Stress and stability of plate-screw fixation and screw fixation in the treatment of Schatzker type IV medial tibial plateau fracture: a comparative finite element study.

Science.gov (United States)

Huang, Xiaowei; Zhi, Zhongzheng; Yu, Baoqing; Chen, Fancheng

2015-11-25

The purpose of this study is to compare the stress and stability of plate-screw fixation and screw fixation in the treatment of Schatzker type IV medial tibial plateau fracture. A three-dimensional (3D) finite element model of the medial tibial plateau fracture (Schatzker type IV fracture) was created. An axial force of 2500 N with a distribution of 60% to the medial compartment was applied to simulate the axial compressive load on an adult knee during single-limb stance. The equivalent von Mises stress, displacement of the model relative to the distal tibia, and displacement of the implants were used as the output measures. The mean stress value of the plate-screw fixation system was 18.78 MPa, which was significantly (P stress value of the triangular fragment in the plate-screw fixation system model was 42.04 MPa, which was higher than that in the screw fixation model (24.18 MPa). But the mean stress of the triangular fractured fragment in the screw fixation model was significantly higher in terms of equivalent von Mises stress (EVMS), x-axis, and z-axis (P < 0.001). This study demonstrated that the load transmission mechanism between plate-screw fixation system and screw fixation system was different and the stability provided by the plate-screw fixation system was superior to the screw fixation system.

Plate Versus Intramedullary Nail Fixation of Anterior Tibial Stress Fractures: A Biomechanical Study.

Science.gov (United States)

Markolf, Keith L; Cheung, Edward; Joshi, Nirav B; Boguszewski, Daniel V; Petrigliano, Frank A; McAllister, David R

2016-06-01

Anterior midtibial stress fractures are an important clinical problem for patients engaged in high-intensity military activities or athletic training activities. When nonoperative treatment has failed, intramedullary (IM) nail and plate fixation are 2 surgical options used to arrest the progression of a fatigue fracture and allow bone healing. A plate will be more effective than an IM nail in preventing the opening of a simulated anterior midtibial stress fracture from tibial bending. Controlled laboratory study. Fresh-frozen human tibias were loaded by applying a pure bending moment in the sagittal plane. Thin transverse saw cuts, 50% and 75% of the depth of the anterior tibial cortex, were created at the midtibia to simulate a fatigue fracture. An extensometer spanning the defect was used to measure the fracture opening displacement (FOD) before and after the application of IM nail and plate fixation constructs. IM nails were tested without locking screws, with a proximal screw only, and with proximal and distal screws. Plates were tested with unlocked bicortical screws (standard compression plate) and locked bicortical screws; both plate constructs were tested with the plate edge placed 1 mm from the anterior tibial crest (anterior location) and 5 mm posterior to the crest. For the 75% saw cut depth, the mean FOD values for all IM nail constructs were 13% to 17% less than those for the saw cut alone; the use of locking screws had no significant effect on the FOD. The mean FOD values for all plate constructs were significantly less than those for all IM nail constructs. The mean FOD values for all plates were 28% to 46% less than those for the saw cut alone. Anterior plate placement significantly decreased mean FOD values for both compression and locked plate constructs, but the mean percentage reductions for locked and unlocked plates were not significantly different from each other for either plate placement. The percentage FOD reductions for all plate

Experimental Fracture Model versus Osteotomy Model in Metacarpal Bone Plate Fixation

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S. Ochman

2011-01-01

Full Text Available Introduction. Osteotomy or fracture models can be used to evaluate mechanical properties of fixation techniques of the hand skeleton in vitro. Although many studies make use of osteotomy models, fracture models simulate the clinical situation more realistically. This study investigates monocortical and bicortical plate fixation on metacarpal bones considering both aforementioned models to decide which method is best suited to test fixation techniques. Methods. Porcine metacarpal bones (=40 were randomized into 4 groups. In groups I and II bones were fractured with a modified 3-point bending test. The intact bones represented a further control group to which the other groups after fixation were compared. In groups III and IV a standard osteotomy was carried out. Bones were fixated with plates monocortically (group I, III and bicortically (group II, IV and tested for failure. Results. Bones fractured at a mean maximum load of 482.8 N ± 104.8 N with a relative standard deviation (RSD of 21.7%, mean stiffness was 122.3 ± 35 N/mm. In the fracture model, there was a significant difference (=0.01 for maximum load of monocortically and bicortically fixed bones in contrast to the osteotomy model (=0.9. Discussion. In the fracture model, because one can use the same bone for both measurements in the intact state and the bone-plate construct states, the impact of inter-individual differences is reduced. In contrast to the osteotomy model there are differences between monocortical and bicortical fixations in the fracture model. Thus simulation of the in vivo situation is better and seems to be suitable for the evaluation of mechanical properties of fixation techniques on metacarpals.

"A" shape plate for open rigid internal fixation of mandible condyle neck fracture.

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Kozakiewicz, Marcin; Swiniarski, Jacek

2014-09-01

Reduction of the fracture is crucial for proper outcome of the treatment. The stability of reduction is closed connected to the method of its fixation. The topic of condylar fracture osteosynthesis still remains highly controversial and challenging. That is why authors decided to propose novel design of the fixating plate and the example of its application. The aim of this study was to present A-shape plate dedicated to rigid fixation of mandible condyle neck fracture. A-shape condylar plate (ACP) design is prepared of 1.0 mm thick titanium alloy (grade 5) sheet: posterior and anterior bars are reinforced by widening to 2.5 mm and anatomically curved along the compression and traction lines in ramus and condylar neck. Superior three-hole-group has triangular organization and located on the level of condylar head. The inferior extensions of the bars are equipped in three holes located at each of lower tails. Connecting bar (2.0 mm wide) connects the first hole of each lower tails closing upper part of ACP in triangular shape. The connecting bar runs along compression line of condylar neck. Holes in ACP has 2.0 mm diameter for locking or normal screws. Height of ACP is 31 mm. The proposed new type of plate was compared by finite element analysis (FEA) to nowadays manufactured 9-hole trapezoid plate as the most similar device. ACP design was evaluated by finite element analysis (FEA) and later applied in patient affected with high condylar neck fracture complicated by fracture of coronoid process. FEA revealed high strength of ACP and more stabile fixation than trapezoid plate. The result was caused by multipoint fixation at three regions of the plate and reinforced bars supported by semi-horizontal connecting bar. Clinical application of ACP was as versatile as makes possible to simultaneous fixation of high condylar neck and coronoid process fracture. Application of proposed A-shape condylar plate would be possible in all levels of neck fractures and can be use

Anterior cervical decompression and fusion with caspar plate fixation

International Nuclear Information System (INIS)

Rehman, L.; Akbar, H.; Das, G.; Hashim, A.S.M.

2013-01-01

Objective: To evaluate the role of anterior cervical decompression and fixation with Caspar plating in cervical spine injury on neurological outcome. Study Design: A case series. Place and Duration of Study: Department of Neurosurgery, Jinnah Postgraduate Medical Centre, Karachi, from July 2008 to March 2011. Methodology: Thirty patients admitted with cervical spine injuries were inducted in the study. All cases were evaluated for their clinical features, level of injury and degree of neurological injury was assessed using Frankel grading. Pre and postoperative record with X-rays and MRI were maintained. Cervical traction was applied to patients with sub-luxation. All patients underwent anterior cervical decompression, fusion and Caspar plate fixation. The follow-up period was 6 months with clinical and radiological assessment. Results: Among 30 patients, 24 (80%) were males and 6 (20%) were females. Age ranged from 15 to 55 years. Causes of injury were road traffic accident (n = 20), fall (n = 8) and assault (n = 2). Commonest mode of injury was road traffic accident (66.6%). Postoperative follow-up showed that pain and neurological deficit were improved in 21 patients. There was no improvement in 7 patients, one patient deteriorated and one expired. All patients developed pain at donor site. Conclusion: Anterior decompression, fusion and fixation with Caspar plate is an effective method with good neurological and radiological outcome. However, it is associated with pain at donor site. (author)

Complications associated with distraction plate fixation of wrist fractures.

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Hanel, Douglas P; Ruhlman, Scott David; Katolik, Leo I; Allan, Christopher H

2010-05-01

This article discusses the major and minor complications of distal plating in the light of a cohort study carried out by the authors, who reviewed all patients undergoing bridge distraction plate fixation of distal radius fractures by three surgeons in a single level I trauma center. The article discusses the effectiveness and the complication rates associated with the technique. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Plate fixation in periprosthetic femur fractures Vancouver type B1-Trochanteric hook plate or subtrochanterical bicortical locking?

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Lenz, Mark; Stoffel, Karl; Kielstein, Heike; Mayo, Keith; Hofmann, Gunther O; Gueorguiev, Boyko

2016-12-01

Proximal plate fixation in periprosthetic femur fractures can be improved by plate anchorage in the greater trochanter (lateral tension band principle) or bicortical locking screw placement beside the prosthesis stem in an embracement configuration. Both concepts were compared in a biomechanical test using a femoral hook plate (hook) or a locking attachment plate (LAP). After bone mineral density (BMD) measurement in the greater trochanter, six pairs of fresh frozen human femora were assigned to two groups and instrumented with cemented hip endoprostheses. A transverse osteotomy was set distal to the tip of the prosthesis, simulating a Vancouver B1 fracture. Each pair was instrumented using a plate tensioner with either hook or LAP construct. Cyclic testing (2Hz) with physiologic profile and monotonically increasing load was performed until catastrophic failure. Plate stiffness was compared in a four-point-bending-test. Paired student's-t-test was used for statistical evaluation (pTrochanteric fixation is highly BMD dependent and may be restricted to major greater trochanteric involvement requiring stabilization. Copyright © 2016 Elsevier Ltd. All rights reserved.

A novel combined method of osteosynthesis in treatment of tibial fractures: a comparative study on sheep with application of rod-through-plate fixator and bone plating.

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Tralman, G; Andrianov, V; Arend, A; Männik, P; Kibur, R T; Nõupuu, K; Uksov, D; Aunapuu, M

2013-04-01

The study compares the efficiency of a new bone fixator combining periostal and intramedullary osteosynthesis to bone plating in treatment of tibial fractures in sheep. Experimental osteotomies were performed in the middle third of the left tibia. Animals were divided into two groups: in one group (four animals) combined osteosynthesis (rod-through-plate fixator, RTP fixator) was applied, and in the other group (three animals) bone plating was used. The experiments lasted for 10 weeks during which fracture union was followed by radiography, and the healing process was studied by blood serum markers reflecting bone turnover and by histological and immunohistochemical investigations. In the RTP fixator group, animals started to load body weight on the operated limbs the next day after the surgery, while in the bone plating group, this happened only on the seventh day. In the RTP fixator group, consolidation of fractures was also faster, as demonstrated by radiographical, histological, and immunohistochemical investigations and in part by blood serum markers for bone formation. It can be concluded that application of RTP fixation is more efficient than plate fixation in the treatment of experimental osteotomies of long bones in sheep. © 2012 Blackwell Verlag GmbH.

Distal femoral osteotomy in genovalgum: internal fixation with blade plate versus casting.

Science.gov (United States)

Makhmalbaf, Hadi; Moradi, Ali; Ganji, Saeid

2014-10-01

To compare the results of two different ways of distal femoral osteotomy stabilization in patients suffering from genuvalgum: internal fixation with plate, and casting. In a non-randomized prospective study, after distal femoral osteotomy with the zigzag method, patients were divided into two groups: long leg casting, and internal fixation with blade plate. For all patients, questionnaires were filled to obtain data. Information such as range of motion, tibiofemoral anatomical angle and complications were recorded. 38 knees with valgus deformity underwent distal femoral supracondylar osteotomy. (8 with plaster cast and 30 with internal fixation using a blade plate). Preoperative range of motion was 129±6° and six months later it was 120±14°. The preoperative tibiofemoral angle was 32±6°; postoperative tibiofemoral angles were 3±3°, 6±2°, and 7±3° just after operation, six months, and two years later, respectively. Although this angle was greater among the group stabilized with a cast, this difference was not statistically significant. In postoperative complications, over-correction was found in five, recorvatom deformity in one, knee stiffness in three and superficial wound infection was recorded in three knees. There is no prominent difference in final range of motion and alignment whether fixation is done with casting or internal fixation. However, the complication rate seems higher in the casting method.

Biomechanical analysis of titanium fixation plates and screws in ...

African Journals Online (AJOL)

hole Y plates with monocortical screws. 150 N incisal occlusal loads were simulated on the models. The commercial ANSYS software was utilized to calculate the Von Mises stresses on fixative appliances. Results: The highest Von Mises stress ...

Plate fixation for proximal chevron osteotomy has greater risk for hallux valgus recurrence than Kirschner wire fixation.

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Park, Chul-Hyun; Ahn, Ji-Yong; Kim, Yu-Mi; Lee, Woo-Chun

2013-06-01

The purpose of this study was to compare the results of hallux valgus surgery between feet fixed with Kirschner wires and those fixed with a plate and screws. Between December 2008 and November 2009, 53 patients (62 feet) were treated with proximal chevron osteotomy and distal soft tissue procedure for symptomatic moderate to severe hallux valgus deformity. Thirty-four patients (41 feet) were stabilised with Kirschner wires (K-wire group) and 19 patients (21 feet) were stabilised with a locking plate (plate group). Clinical results were assessed using American Orthopaedic Foot and Ankle Society (AOFAS) score. Radiographic parameters were compared between these groups. Recurrence rate at the last follow-up was compared between the K-wire and plate groups. Mean AOFAS score was lower in the plate group, however, the difference between the groups was not statistically significant in AOFAS score at the last follow-up. Hallux valgus angle and intermetatarsal angle were significantly larger in the plate group at the last follow-up. Mean 1-2 metatarsal (MT) distance on immediately postoperative radiographs was significant larger in the plate group. Four (9.8 %) of the 41 feet in the K-wire group and 7 (33.3 %) of the 21 feet in the plate group showed hallux valgus recurrence at the last follow-up. The plate group had a significantly higher risk of recurrence than the K-wire group. Fixation of proximal chevron osteotomy using a plate and screws has a greater risk of hallux valgus recurrence than fixation using Kirschner wires.

CAD-CAM plates versus conventional fixation plates for primary mandibular reconstruction: A biomechanical in vitro analysis.

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Rendenbach, Carsten; Sellenschloh, Kay; Gerbig, Lucca; Morlock, Michael M; Beck-Broichsitter, Benedicta; Smeets, Ralf; Heiland, Max; Huber, Gerd; Hanken, Henning

2017-11-01

CAD/CAM reconstruction plates have become a viable option for mandible reconstruction. The aim of this study was to determine whether CAD/CAM plates provide higher fatigue strength compared with conventional fixation systems. 1.0 mm miniplates, 2.0 mm conventional locking plates (DePuy Synthes, Umkirch, Germany), and 2.0 mm CAD/CAM plates (Materialise, Leuven, Belgium/DePuy Synthes) were used to reconstruct a polyurethane mandible model (Synbone, Malans, CH) with cortical and cancellous bone equivalents. Mastication was simulated via cyclic dynamic testing using a universal testing machine (MTS, Bionix, Eden Prairie, MN, USA) until material failure reached a rate of 1 Hz with increasing loads on the left side. No significant difference was found between the groups until a load of 300 N. At higher loads, vertical displacement differed increasingly, with a poorer performance of miniplates (p = 0.04). Plate breakage occurred in miniplates and conventional locking plates. Screw breakage was recorded as the primary failure mechanism in CAD/CAM plates. Stiffness was significantly higher with the CAD/CAM plates (p = 0.04). CAD/CAM plates and reconstruction plates provide higher fatigue strength than miniplates, and stiffness is highest in CAD/CAM systems. All tested fixation methods seem sufficiently stable for mandible reconstruction. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Biomechanical stability of a supra-acetabular pedicle screw internal fixation device (INFIX) vs external fixation and plates for vertically unstable pelvic fractures.

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Vigdorchik, Jonathan M; Esquivel, Amanda O; Jin, Xin; Yang, King H; Onwudiwe, Ndidi A; Vaidya, Rahul

2012-09-27

We have recently developed a subcutaneous anterior pelvic fixation technique (INFIX). This internal fixator permits patients to sit, roll over in bed and lie on their sides without the cumbersome external appliances or their complications. The purpose of this study was to evaluate the biomechanical stability of this novel supraacetabular pedicle screw internal fixation construct (INFIX) and compare it to standard internal fixation and external fixation techniques in a single stance pelvic fracture model. Nine synthetic pelves with a simulated anterior posterior compression type III injury were placed into three groups (External Fixator, INFIX and Internal Fixation). Displacement, total axial stiffness, and the stiffness at the pubic symphysis and SI joint were calculated. Displacement and stiffness were compared by ANOVA with a Bonferroni adjustment for multiple comparisons The mean displacement at the pubic symphysis was 20, 9 and 0.8 mm for external fixation, INFIX and internal fixation, respectively. Plate fixation was significantly stiffer than the INFIX and external Fixator (P = 0.01) at the symphysis pubis. The INFIX device was significantly stiffer than external fixation (P = 0.017) at the symphysis pubis. There was no significant difference in SI joint displacement between any of the groups. Anterior plate fixation is stiffer than both the INFIX and external fixation in single stance pelvic fracture model. The INFIX was stiffer than external fixation for both overall axial stiffness, and stiffness at the pubic symphysis. Combined with the presumed benefit of minimizing the complications associated with external fixation, the INFIX may be a more preferable option for temporary anterior pelvic fixation in situations where external fixation may have otherwise been used.

Posterior column acetabular fracture fixation using a W-shaped angular plate: A biomechanical analysis.

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Ke Su

Full Text Available The purpose of this study was to compare the stability and feasibility of four fixation constructs in a posterior column acetabular fracture: one reconstruction plate, one reconstruction plate and lag screw, two reconstruction plates, and a W-shaped acetabular angular plate.Twenty embalmed cadaveric pelvises with a posterior column acetabular fractures were allocated to one of four groups: 1 a reconstruction plate, 2 a reconstruction plate with a posterior column lag screw, 3 double reconstruction plates, and 4 a W-shaped acetabular angular plate. These constructs were mechanically loaded on a testing machine, and construct stiffness values were measured. Strain gauges were utilized to measure the mechanical behavior in the condition of compressive force.Final stiffness was not different between the two reconstruction plates (445.81±98.30 N/mm and the W-shaped acetabular angular plate (447.43±98.45 N/mm, p = 0.524, both of which were superior to a single reconstruction plate (248.90±61.95 N/mm and a combined plate and lag screw (326.41±94.34 N/mm. Following the fixation of the W-shaped acetabular angular plate, the strain distribution was similar to the intact condition around the acetabulum. The parameters of the W-shaped acetabular angular plate that were observed at the superior region of the acetabulum were less than those of a single reconstruction plate (p<0.05, a single reconstruction plate with lag screw (p<0.05, and two reconstruction plates (p<0.05.The novel W-shaped acetabular angular plate fixation technique was able to provide the biomechanically stiffest construct for stabilization of a posterior column acetabular fracture; it also resulted in a partial restoration of joint loading parameters toward the intact state.

Sternal plate fixation for sternal wound reconstruction: initial experience (Retrospective study

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Musgrave Melinda

2011-04-01

Full Text Available Abstract Background Median sternotomy infection and bony nonunion are two commonly described complications which occur in 0.4 - 5.1% of cardiac procedures. Although relatively infrequent, these complications can lead to significant morbidity and mortality. The aim of this retrospective study is to evaluate the initial experience of a transverse plate fixation system following wound complications associated with sternal dehiscence with or without infection following cardiac surgery. Methods A retrospective chart review of 40 consecutive patients who required sternal wound reconstruction post sternotomy was performed. Soft tissue debridement with removal of all compromised tissue was performed. Sternal debridement was carried using ronguers to healthy bleeding bone. All patients underwent sternal fixation using three rib plates combined with a single manubrial plate (Titanium Sternal Fixation System®, Synthes. Incisions were closed in a layered fashion with the pectoral muscles being advanced to the midline. Data were expressed as mean ± SD, Median (range or number (%. Statistical analyses were made by using Excel 2003 for Windows (Microsoft, Redmond, WA, USA. Results There were 40 consecutive patients, 31 males and 9 females. Twenty two patients (55% were diagnosed with sternal dehiscence alone and 18 patients (45% with associated wound discharge. Thirty eight patients went on to heal their wounds. Two patients developed recurrent wound infection and required VAC therapy. Both were immunocompromised. Median post-op ICU stay was one day with the median hospital stay of 18 days after plating. Conclusion Sternal plating appears to be an effective option for the treatment of sternal wound dehiscence associated with sternal instability. Long-term follow-up and further larger studies are needed to address the indications, benefits and complications of sternal plating.

To evaluate the efficacy of biodegradable plating system for fixation of maxillofacial fractures: A prospective study

OpenAIRE

Bali, Rishi K.; Sharma, Parveen; Jindal, Shalu; Gaba, Shivani

2013-01-01

Aims: The present study was undertaken to evaluate the efficacy of biodegradable plating system for fixation of maxillofacial fractures and to study the morbidity associated with the use of biodegradable plates and screws. Materials and Methods: This prospective study consisted of 10 patients with maxillofacial fractures requiring open reduction and internal fixation. Fractures with infection, comminuted and pathological fractures were excluded. All were plated with biodegradable system (Inio...

Fracture healing using degradable magnesium fixation plates and screws.

Science.gov (United States)

Chaya, Amy; Yoshizawa, Sayuri; Verdelis, Kostas; Noorani, Sabrina; Costello, Bernard J; Sfeir, Charles

2015-02-01

Internal bone fixation devices made with permanent metals are associated with numerous long-term complications and may require removal. We hypothesized that fixation devices made with degradable magnesium alloys could provide an ideal combination of strength and degradation, facilitating fracture fixation and healing while eliminating the need for implant removal surgery. Fixation plates and screws were machined from 99.9% pure magnesium and compared with titanium devices in a rabbit ulnar fracture model. Magnesium device degradation and the effect on fracture healing and bone formation were assessed after 4 weeks. Fracture healing with magnesium device fixation was compared with that of titanium devices using qualitative histologic analysis and quantitative histomorphometry. Micro-computed tomography showed device degradation after 4 weeks in vivo. In addition, 2-dimensional micro-computed tomography slices and histologic staining showed that magnesium degradation did not inhibit fracture healing or bone formation. Histomorphology showed no difference in bone-bridging fractures fixed with magnesium and titanium devices. Interestingly, abundant new bone was formed around magnesium devices, suggesting a connection between magnesium degradation and bone formation. Our results show potential for magnesium fixation devices in a loaded fracture environment. Furthermore, these results suggest that magnesium fixation devices may enhance fracture healing by encouraging localized new bone formation. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Angular-stable locking plate fixation of tibial plateau fractures-clinical and radiological midterm results in 101 patients

OpenAIRE

Sven Mardian; Felix Landmann; Florian Wichlas; Norbert P Haas; Klaus-Dieter Schaser; Philipp Schwabe

2015-01-01

Background: Articular reconstruction and stable fixation of tibial plateau fractures and its various subtypes continue to represent a surgical challenge. Only few trials have studied results following angular stable plate fixation. The present study aimed to investigate the clinical, radiological, functional and quality of life results following tibial plateau fractures using angular stable plate fixation. Materials and Methods: 101 patients were retrospectively studied using functional (...

A customized fixation plate with novel structure designed by topological optimization for mandibular angle fracture based on finite element analysis.

Science.gov (United States)

Liu, Yun-Feng; Fan, Ying-Ying; Jiang, Xian-Feng; Baur, Dale A

2017-11-15

The purpose of this study was to design a customized fixation plate for mandibular angle fracture using topological optimization based on the biomechanical properties of the two conventional fixation systems, and compare the results of stress, strain and displacement distributions calculated by finite element analysis (FEA). A three-dimensional (3D) virtual mandible was reconstructed from CT images with a mimic angle fracture and a 1 mm gap between two bone segments, and then a FEA model, including volume mesh with inhomogeneous bone material properties, three loading conditions and constraints (muscles and condyles), was created to design a customized plate using topological optimization method, then the shape of the plate was referenced from the stress concentrated area on an initial part created from thickened bone surface for optimal calculation, and then the plate was formulated as "V" pattern according to dimensions of standard mini-plate finally. To compare the biomechanical behavior of the "V" plate and other conventional mini-plates for angle fracture fixation, two conventional fixation systems were used: type A, one standard mini-plate, and type B, two standard mini-plates, and the stress, strain and displacement distributions within the three fixation systems were compared and discussed. The stress, strain and displacement distributions to the angle fractured mandible with three different fixation modalities were collected, respectively, and the maximum stress for each model emerged at the mandibular ramus or screw holes. Under the same loading conditions, the maximum stress on the customized fixation system decreased 74.3, 75.6 and 70.6% compared to type A, and 34.9, 34.1, and 39.6% compared to type B. All maximum von Mises stresses of mandible were well below the allowable stress of human bone, as well as maximum principal strain. And the displacement diagram of bony segments indicated the effect of treatment with different fixation systems. The

Anatomically contoured plates for fixation of rib fractures.

Science.gov (United States)

Bottlang, Michael; Helzel, Inga; Long, William B; Madey, Steven

2010-03-01

: Intraoperative contouring of long bridging plates for stabilization of flail chest injuries is difficult and time consuming. This study implemented for the first time biometric parameters to derive anatomically contoured rib plates. These plates were tested on a range of cadaveric ribs to quantify plate fit and to extract a best-fit plating configuration. : Three left and three right rib plates were designed, which accounted for anatomic parameters required when conforming a plate to the rib surface. The length lP over which each plate could trace the rib surface was evaluated on 109 cadaveric ribs. For each rib level 3-9, the plate design with the highest lP value was extracted to determine a best-fit plating configuration. Furthermore, the characteristic twist of rib surfaces was measured on 49 ribs to determine the surface congruency of anatomic plates with a constant twist. : The tracing length lP of the best-fit plating configuration ranged from 12.5 cm to 14.7 cm for ribs 3-9. The corresponding range for standard plates was 7.1-13.7 cm. The average twist of ribs over 8-cm, 12-cm, and 16-cm segments was 8.3 degrees, 20.6 degrees, and 32.7 degrees, respectively. The constant twist of anatomic rib plates was not significantly different from the average rib twist. : A small set of anatomic rib plates can minimize the need for intraoperative plate contouring for fixation of ribs 3-9. Anatomic rib plates can therefore reduce the time and complexity of flail chest stabilization and facilitate spanning of flail segments with long plates.

A cell shrinkage artefact in growth plate chondrocytes with common fixative solutions: importance of fixative osmolarity for maintaining morphology

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MY Loqman

2010-05-01

Full Text Available The remarkable increase in chondrocyte volume is a major determinant in the longitudinal growth of mammalian bones. To permit a detailed morphological study of hypertrophic chondrocytes using standard histological techniques, the preservation of normal chondrocyte morphology is essential. We noticed that during fixation of growth plates with conventional fixative solutions, there was a marked morphological (shrinkage artifact, and we postulated that this arose from the hyper-osmotic nature of these solutions. To test this, we fixed proximal tibia growth plates of 7-day-old rat bones in either (a paraformaldehyde (PFA; 4%, (b glutaraldehyde (GA; 2% with PFA (2% with ruthenium hexamine trichloride (RHT; 0.7%, (c GA (2% with RHT (0.7%, or (d GA (1.3% with RHT (0.5% and osmolarity adjusted to a ‘physiological’ level of ~280mOsm. Using conventional histological methods, confocal microscopy, and image analysis on fluorescently-labelled fixed and living chondrocytes, we then quantified the extent of cell shrinkage and volume change. Our data showed that the high osmolarity of conventional fixatives caused a shrinkage artefact to chondrocytes. This was particularly evident when whole bones were fixed, but could be markedly reduced if bones were sagittally bisected prior to fixation. The shrinkage artefact could be avoided by adjusting the osmolarity of the fixatives to the osmotic pressure of normal extracellular fluids (~280mOsm. These results emphasize the importance of fixative osmolarity, in order to accurately preserve the normal volume/morphology of cells within tissues.

Standard specification for tantalum and tantalum alloy plate, sheet, and strip. ASTM standard

International Nuclear Information System (INIS)

1998-09-01

This specification is under the jurisdiction of ASTM Committee B-10 on Reactive and Refractory Metals and Alloys and is the direct responsibility of Subcommittee B10.03 on Niobium and Tantalum. Current edition approved May 10, 1998 and published September 1998. Originally published as B 708-82. Last previous edition was B 708-92

Locking plate fixation in distal metaphyseal tibial fractures: series of 79 patients

OpenAIRE

Gupta, Rakesh K.; Rohilla, Rajesh Kumar; Sangwan, Kapil; Singh, Vijendra; Walia, Saurav

2009-01-01

Open reduction and internal fixation in distal tibial fractures jeopardises fracture fragment vascularity and often results in soft tissue complications. Minimally invasive osteosynthesis, if possible, offers the best possible option as it permits adequate fixation in a biological manner. Seventy-nine consecutive adult patients with distal tibial fractures, including one patient with a bilateral fracture of the distal tibia, treated with locking plates, were retrospectively reviewed. The 4.5-...

Dual small fragment plating improves screw-to-screw load sharing for mid-diaphyseal humeral fracture fixation: a finite element study.

Science.gov (United States)

Kosmopoulos, Victor; Luedke, Colten; Nana, Arvind D

2015-01-01

A smaller humerus in some patients makes the use of a large fragment fixation plate difficult. Dual small fragment plate constructs have been suggested as an alternative. This study compares the biomechanical performance of three single and one dual plate construct for mid-diaphyseal humeral fracture fixation. Five humeral shaft finite element models (1 intact and 4 fixation) were loaded in torsion, compression, posterior-anterior (PA) bending, and lateral-medial (LM) bending. A comminuted fracture was simulated by a 1-cm gap. Fracture fixation was modelled by: (A) 4.5-mm 9-hole large fragment plate (wide), (B) 4.5-mm 9-hole large fragment plate (narrow), (C) 3.5-mm 9-hole small fragment plate, and (D) one 3.5-mm 9-hole small fragment plate and one 3.5-mm 7-hole small fragment plate. Model A showed the best outcomes in torsion and PA bending, whereas Model D outperformed the others in compression and LM bending. Stress concentrations were located near and around the unused screw holes for each of the single plate models and at the neck of the screws just below the plates for all the models studied. Other than in PA bending, Model D showed the best overall screw-to-screw load sharing characteristics. The results support using a dual small fragment locking plate construct as an alternative in cases where crutch weight-bearing (compression) tolerance may be important and where anatomy limits the size of the humerus bone segment available for large fragment plate fixation.

What is the Effect of 90-Degree Double-Plate Fixation with Grafting on Healing of Humeral Shaft Non-unions

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Mutlu Çobanoğlu

2016-08-01

Full Text Available Objective: Our aim was to investigate the clinical and radiological outcomes of double-plate fixation with grafting in the treatment of non-union of humeral shaft fractures. Materials and Methods: We performed a retrospective chart review of patients operated between 2006 and 2012 due to humeral shaft non-union. Patients undergoing surgery with double-plate fixation were included and those treated with external fixator, single plate, intramedullary nails and patients with pathological fractures and infected non-unions were excluded. Surgical intervention via anterolateral or posterior approach included radial nerve identification, decortication and reestablishment of medullary canal followed by compression plating with double-plate fixation and frequent application of autogenous grafts or allografts. Main outcome measures were success rate of non-union repair, rate of re-intervention and complications, range of motion, assessment of pain Visual analogue scale (VAS and function Disabilities of the arm, shoulder and hand (DASH and overall outcome Stewart-Hundley classification. Results: Ten patients were treated with double-plate fixation. The study group included six females and four males aged 36 to 70 years. Union was achieved within 4.5 and 8 months in all cases. The mean preoperative VAS score of 6.1 decreased to 2, postoperatively, with an associated decrease in the mean DASH score from 74.1 to 23.4. Excellent or good results were obtained in nine cases. There was no incidence of radial nerve palsy or infection. Conclusion: Our study provides level 4 evidence of the effectiveness of treating non-union fractures of the humeral shaft with double-plate fixation and grafting in providing good-to-excellent functional results and high union rate without any significant complication.

Study of the formation process and the characteristics of tantalum layers electrodeposited on Nitinol plates in the 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid

International Nuclear Information System (INIS)

Maho, A.; Delhalle, J.; Mekhalif, Z.

2013-01-01

Highlights: ► Tantalum electrodeposition on Nitinol plates in the [BMP]Tf 2 N ionic liquid at room temperature. ► Generation of intrinsically nanostructured porous tantalum layers in “soft” cathodic current conditions. ► Important impact of substrate nature, working solution composition and electrodeposition duration. ► Primary assessment of surface corrosion resistance and bioactivity. -- Abstract: Thanks to excellent mechanical and biochemical properties, the nickel–titanium shape memory alloy (Nitinol) constitutes an increasingly praised platform material in dental, cardiovascular and orthopedic biomedical devices. In order to strengthen their protective abilities toward corrosion, to reinforce their biocompatibility and to confer them specific osseointegrative capacities, Nitinol plates are covered with a thin tantalum layer by electrodeposition in the 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid. XPS and SEM/EDX analyses highlight the chemical and morphological characteristics of the deposits: notably, these present an intrinsic dimpled nanometric structuration which is particularly remarkable considering the “soft” experimental conditions and very interesting for fundamental and applied bioactive perspectives. The present study investigates the specific and synergic effects of the Ni occurrence on the surface of the Nitinol substrates, the presence of fluorine species in the working bath, and the electrodeposition duration on the resulting formation process, morphology and chemical composition of the tantalum coating. Finally, samples are submitted to electrochemical characterizations and in vitro hydroxyapatite growth tests for a primary assessment of their corrosion resistance and osseoinductive features

Locking plate fixation in distal metaphyseal tibial fractures: series of 79 patients.

Science.gov (United States)

Gupta, Rakesh K; Rohilla, Rajesh Kumar; Sangwan, Kapil; Singh, Vijendra; Walia, Saurav

2010-12-01

Open reduction and internal fixation in distal tibial fractures jeopardises fracture fragment vascularity and often results in soft tissue complications. Minimally invasive osteosynthesis, if possible, offers the best possible option as it permits adequate fixation in a biological manner. Seventy-nine consecutive adult patients with distal tibial fractures, including one patient with a bilateral fracture of the distal tibia, treated with locking plates, were retrospectively reviewed. The 4.5-mm limited-contact locking compression plate (LC-LCP) was used in 33 fractures, the metaphyseal LCP in 27 fractures and the distal medial tibial LCP in the remaining 20 fractures. Fibula fixation was performed in the majority of comminuted fractures (n = 41) to maintain the second column of the ankle so as to achieve indirect reduction and to prevent collapse of the fracture. There were two cases of delayed wound breakdown in fractures fixed with the 4.5-mm LC-LCP. Five patients required primary bone grafting and three patients required secondary bone grafting. All cases of delayed union (n = 7) and nonunion (n = 3) were observed in cases where plates were used in bridge mode. Minimally invasive plate osteosynthesis (MIPO) with LCP was observed to be a reliable method of stabilisation for these fractures. Peri-operative docking of fracture ends may be a good option in severely impacted fractures with gap. The precontoured distal medial tibial LCP was observed to be a better tolerated implant in comparison to the 4.5-mm LC-LCP or metaphyseal LCP with respect to complications of soft tissues, bone healing and functional outcome, though its contour needs to be modified.

Lateral column lengthening using allograft interposition and cervical plate fixation.

Science.gov (United States)

Philbin, Terrence M; Pokabla, Christopher; Berlet, Gregory C

2008-10-01

Lateral column lengthening has been used successfully in the treatment of stage II adult-acquired pes planovalgus deformity. The purpose of this study is to review the union rate when allograft material is used and the osteotomy stabilized with a cervical plate. A retrospective review was performed on 28 feet in 26 patients who underwent correction of stage II pes planovalgus deformity using a lateral column lengthening with allograft tricortical iliac crest stabilized with a cervical plate. Patients were evaluated preoperatively and postoperatively using a modified American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale and the Short Form-12 health survey, as well as radiographically by assessing the talonavicular coverage angle. At a mean follow-up of 9 months, the mean total modified AOFAS score and pain subscore were significantly higher (45.6 and 25.0, respectively) versus preoperatively (27.3 and 11.2, respectively). Graft incorporation occurred in all but one case, and the average length of time to union was 10.06 weeks. Complications included 4 hardware removals, 1 nonunion, 1 graft penetration of the calcaneocuboid joint, and 2 cases of calcaneocuboid joint arthritis. Lateral column lengthening using allograft tricortical iliac crest bone graft with cervical plate fixation is a viable option for the correction of acquired pes planovalgus deformity. Allograft bone avoids donor site morbidity of autogenous iliac crest grafts and was not shown to increase rates of nonunion. Cervical plate fixation avoids the necessity of penetrating the graft with a screw and is associated with high patient satisfaction and radiographic union.

Durability of adhesive bonds to uranium alloys, tungsten, tantalum, and thorium

International Nuclear Information System (INIS)

Childress, F.G.

1975-01-01

Long-term durability of epoxy bonds to alloys of uranium (U-Nb and Mulberry), nickel-plated uranium, thorium, tungsten, tantalum, tantalum--10 percent tungsten, and aluminum was evaluated. Significant strengths remain after ten years of aging; however, there is some evidence of bond deterioration with uranium alloys and thorium stored in ambient laboratory air

Morphological analysis of acromion and hook plate for the fixation of acromioclavicular joint dislocation.

Science.gov (United States)

Yoon, Jong Pil; Lee, Yeon Soo; Song, Geun Soo; Oh, Joo Han

2017-03-01

Acromioclavicular (AC) joint dislocation is a common sports injury. Hook plate fixation is currently widely used to treat this injury, as it can promote the natural healing of the ligament with good clinical outcomes. However, subacromial erosion and impingement are frequently observed post-operatively. It was hypothesized that the morphology and the contact characteristics between the hook portion and the acromion are the main causes of complications after hook plate fixation with the currently available commercial designs. Three-dimensional reconstructed models of the AC joint obtained from the computed tomographic scans of 23 male and 23 female patients (mean age, 61.1 ± 6.3 years) were evaluated, and multiple anatomical parameters were measured. For the subacromial positioning of the hook plate, an actual hook plate (Synthes Inc., West Chester, PA, USA) was scanned, and the contact between the hook plate and the acromion was estimated. The thicknesses of the acromion and distal clavicle were 9.7 ± 1.5 mm (10.7 mm in men; 8.6 mm in women) and 11.3 ± 1.6 mm (11.6 mm in men; 10.0 mm in women), respectively. The width of the acromion was 28.5 ± 3.6 mm. The mean inclination angle between the hook plate and the acromion was 29.3° ± 9.7° (27.9° in men; 30.6° in women). The hook plate made a point contact with the acromion at 9.2 ± 3.3 mm (31.5 %) from the lateral end of the acromion. The results revealed that the hook made a pinpoint contact with the undersurface of the acromion, and this might explain why complications commonly occur after hook plate fixation. The force concentration phenomenon associated with the hook plate of existing designs results from cases of morphological mismatch, such as excessive inclination and improper occupation of the subacromial space.

Low-profile plate fixation in arthrodesis of the first metacarpophalangeal joint

DEFF Research Database (Denmark)

Rasmussen, Claudia; Roos, S; Boeckstyns, M

2011-01-01

case a tenolysis. Follow-up time was 13-92 months (mean 52). There was no correlation between patient satisfaction and position of fusion. We conclude that this technique gives a high rate of union, a short period of immobilization and rehabilitation, and a reliable position at the site of fusion.......Fifty-one consecutive arthrodeses (46 patients) of the first metacarpophalangeal joint were retrospectively reviewed, after fixation with a Leibinger low-profile titanium plate, using a cup-and-cone technique. Primary bone union was achieved in 98%. Three cases required removal of the plate and one...

Navigation-aided visualization of lumbosacral nerves for anterior sacroiliac plate fixation: a case report.

Science.gov (United States)

Takao, Masaki; Nishii, Takashi; Sakai, Takashi; Sugano, Nobuhiko

2014-06-01

Anterior sacroiliac joint plate fixation for unstable pelvic ring fractures avoids soft tissue problems in the buttocks; however, the lumbosacral nerves lie in close proximity to the sacroiliac joint and may be injured during the procedure. A 49 year-old woman with a type C pelvic ring fracture was treated with an anterior sacroiliac plate using a computed tomography (CT)-three-dimensional (3D)-fluoroscopy matching navigation system, which visualized the lumbosacral nerves as well as the iliac and sacral bones. We used a flat panel detector 3D C-arm, which made it possible to superimpose our preoperative CT-based plan on the intra-operative 3D-fluoroscopic images. No postoperative complications were noted. Intra-operative lumbosacral nerve visualization using computer navigation was useful to recognize the 'at-risk' area for nerve injury during anterior sacroiliac plate fixation. Copyright © 2013 John Wiley & Sons, Ltd.

Treatment of midshaft clavicular nonunion with plate fixation and autologous bone grafting

DEFF Research Database (Denmark)

Olsen, Bo Sanderhoff; Vaesel, M T; Søjbjerg, Jens Ole

1995-01-01

We studied the results of 16 consecutive midshaft clavicular nonunions operated on at the Shoulder and Elbow Clinic during the period from 1990 to 1993. All patients were treated with rigid 3.5 mm plate fixation and autologous cancellous bone grafting. Union of the fractures was achieved in all...... except one case, with a reconstruction ratio (restoration of bone length) of 0.96 (range 0.88 to 1.03). At follow-up 12 of 16 patients had returned to their preinjury activity level and according to the Constant score had obtained an excellent result. Two patients were graded as good, one as fair......, and one had a failure. Thirteen of 16 patients were satisfied with the cosmetic outcome, assessing their cosmetic result as either good or excellent. Rigid plate fixation and restoration of clavicular length with autologous cancellous bone graft is recommended for the treatment of symptomatic clavicular...

Fixation of supraglenoid tubercle fractures using distal femoral locking plates in three Warmblood horses.

Science.gov (United States)

Frei, Sina; Fürst, Anton E; Sacks, Murielle; Bischofberger, Andrea S

2016-05-18

Three horses that were presented with supraglenoid tubercle fractures were treated with open reduction and internal fixation using distal femoral locking plates (DFLP). Placing the DFLP caudal to the scapular spine in order to preserve the suprascapular nerve led to a stable fixation, however, it resulted in infraspinatus muscle atrophy and mild scapulohumeral joint instability (case 1). Placing the DFLP cranial to the scapular spine and under the suprascapular nerve resulted in a stable fixation, however, it resulted in severe atrophy of the supraspinatus and infraspinatus muscles and scapulohumeral joint instability (case 2). Placing the DFLP cranial to the scapular spine and slightly overbending it at the suprascapular nerve passage site resulted in the best outcome (case 3). Only a mild degree of supraspinatus and infraspinatus muscle atrophy was apparent, which resolved quickly and with no effect on scapulohumeral joint stability. In all cases, fixation of supraglenoid tubercle fractures using DFLP in slightly different techniques led to stable fixations with good long-term outcome. One case suffered from a mild incisional infection and plates were removed in two horses. Placement of the DFLP cranial to the scapular spine and slightly overbending it at the suprascapular nerve passage prevented major nerve damage. Further cases investigating the degree of muscle atrophy following the use of the DFLP placed in the above-described technique are justified to improve patient outcome.

FUNCTIONAL OUTCOME OF SUPRACONDYLAR FRACTURES OF FEMUR MANAGED BY OPEN REDUCTION AND INTERNAL FIXATION WITH LOCKING COMPRESSION PLATE

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Madhusudhana

2015-10-01

Full Text Available INTRODUCTION : Incidence of distal femur fractures is approximately 37 per 1 , 00,000 person - years.¹Distal femoral fractures has two different injury mechanisms, high energy trauma and low energy trauma. In high - energy trauma, the problem of restoring the function in a destroyed knee joint persists. Complex knee ligament injuries frequently occur additionally to extensive cartilage injuries. In elderly patients, extreme osteoporosis represents a particular problem for anchoring the implant. 2 Supracondylar and inter condylar fractures often are unstable and comminuted and tend to occur in the elderly or those with multiple injuries. Treatment options are many with varied results. The final outcome would depend upon the type of fracture, stabilization of fixation and and perhaps patient general condition. 3 The options for operative treatment are traditional plating techniques that require compression of the implant to the femoral shaft (blade plate, Dynamic Condylar Screw, non - locking condylar buttress plate, antegrade nailing fixation, retrograde nailing, sub muscular locked internal fixation and external fixation. 4 However, as the complexity of fractures needing treatment has changed from simple extra - articular supra - condylar types to inter - condylar and metaphyseal comminuted types, these implants may not be ideal. Double plating, and more recently, locked plating techniques have been advocated 5 . However with double plating there is often extensive soft tissue stripping on both sides of the femur, resulting in reduced blood supply and potential non - union and failure of the implants 6 . The LCP is a single beam construct where the strength of its fixation is equal to the sum of all screw - bone interfaces rather than a single screw’s axial stiffness or pullout resistance as seen in unlocked plates 7,8 . Its unique biomechanical function is based on splinting rather than compression resulting in flexible stabilization

UK DRAFFT - A randomised controlled trial of percutaneous fixation with kirschner wires versus volar locking-plate fixation in the treatment of adult patients with a dorsally displaced fracture of the distal radius

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Brown Jaclyn

2011-09-01

Full Text Available Abstract Background Fractures of the distal radius are extremely common injuries in adults. However, the optimal management remains controversial. In general, fractures of the distal radius are treated non-operatively if the bone fragments can be held in anatomical alignment by a plaster cast or orthotic. However, if this is not possible, then operative fixation is required. There are several operative options but the two most common in the UK, are Kirschner-wire fixation (K-wires and volar plate fixation using fixed-angle screws (locking-plates. The primary aim of this trial is to determine if there is a difference in the Patient-Reported Wrist Evaluation one year following K-wire fixation versus locking-plate fixation for adult patients with a dorsally-displaced fracture of the distal radius. Methods/design All adult patients with an acute, dorsally-displaced fracture of the distal radius, requiring operative fixation are potentially eligible to take part in this study. A total of 390 consenting patients will be randomly allocated to either K-wire fixation or locking-plate fixation. The surgery will be performed in trauma units across the UK using the preferred technique of the treating surgeon. Data regarding wrist function, quality of life, complications and costs will be collected at six weeks and three, six and twelve months following the injury. The primary outcome measure will be wrist function with a parallel economic analysis. Discussion This pragmatic, multi-centre trial is due to deliver results in December 2013. Trial registration Current Controlled Trials ISRCTN31379280 UKCRN portfolio ID 8956

Graft fixation with predetermined tension using a new device, the double spike plate.

Science.gov (United States)

Shino, Konsei; Mae, Tatsuo; Maeda, Akira; Miyama, Takahide; Shinjo, Hirotaka; Kawakami, Hideo

2002-10-01

To biomechanically evaluate a new fixation device, DSP (Double Spike Plate; Meira Corp, Nagoya, Aichi, Japan), for pullout graft fixation. Biomechanical study. A porcine tibia in which 8-mm diameter drill holes had been made from the medial tibial metaphysis to the anterior cruciate ligament attachment was rigidly fixed to a tension analyzer. A quadrupled graft consisting of 2 double-looped bovine tendons was prepared with No. 3 polyester sutures placed distally. The graft was passed through the drill hole, and its proximal loop ends were rigidly fixed to a load cell for monitoring graft tension. The graft's distal ends were connected to the DSP by tying the sutures to the top hole in the DSP. The graft tension was predetermined at 49 N (n = 5) or 98 N (n = 5). This tension was maintained for 5 minutes with a suture passed through the bottom hole of the DSP. The plate was fixed to the tibia by hammering its spikes into the bone under the index tension. Finally, the fixation was completed by inserting a screw. Although the graft tension immediately increased to 69 +/- 11 N or 133 +/- 14 N during hammering, it gradually reduced to 49 +/- 10 N or 100 +/- 7 N 5 minutes later. This study shows that graft fixation under a predetermined tension can be achieved with the DSP.

PEEK versus titanium locking plates for proximal humerus fracture fixation: a comparative biomechanical study in two- and three-part fractures.

Science.gov (United States)

Schliemann, Benedikt; Seifert, Robert; Theisen, Christina; Gehweiler, Dominic; Wähnert, Dirk; Schulze, Martin; Raschke, Michael J; Weimann, Andre

2017-01-01

The high rigidity of metal implants may be a cause of failure after fixation of proximal humerus fractures. Carbon fiber-reinforced polyetheretherketone (PEEK) plates with a modulus similar to human cortical bone may help to overcome this problem. The present study assesses the biomechanical behavior of a PEEK plate compared with a titanium locking plate. Unstable two- and three-part fractures were simulated in 12 pairs of cadaveric humeri and were fixed with either a PEEK or a titanium locking plate using a pairwise comparison. With an optical motion capture system, the stiffness, failure load, plate bending, and the relative motion at the bone-implant interface and at the fracture site were evaluated. The mean load to failure for two- and three-part fracture fixations was, respectively, 191 N (range 102-356 N) and 142 N (range 102-169 N) in the PEEK plate group compared with 286 N (range 191-395 N) and 258 N (range 155-366 N) in the titanium locking plate group. The PEEK plate showed significantly more bending in both the two- and three-part fractures (p PEEK plate showed lower fixation strength and increased motion at the bone-implant interface compared with a titanium locking plate.

Kinetic Study of the Chemical Vapor Deposition of Tantalum in Long Narrow Channels

DEFF Research Database (Denmark)

Mugabi, James Atwoki; Eriksen, Søren; Petrushina, Irina

2016-01-01

A kinetic study of the chemical vapor deposition of tantalum in long narrow channels is done to optimize the industrial process for the manufacture of tantalum coated plate heat exchangers. The developed model fits well at temperatures between 750 and 850 °C, and in the pressure range of25–990 mbar....... According to the model, the predominant tantalum growth species is TaCl3. The temperature is shown to have a pronounced effect onthe morphology and rate of deposition of the tantalum and an apparent change in deposition mechanism occurs between 850–900 °C, resulting in the deposition rate at 900 °C being...

Anterior Z-plate and titanic mesh fixation for acute burst thoracolumbar fracture.

Science.gov (United States)

Xu, Jian-Guang; Zeng, Bing-Fang; Zhou, Wei; Kong, Wei-Qing; Fu, Yi-Shan; Zhao, Bi-Zeng; Zhang, Tao; Lian, Xiao-Feng

2011-04-01

A retrospective study. To evaluate the clinical outcome, effectiveness, and security of the surgical management of acute thoracolumbar burst fracture with corpectomy, titanic mesh autograft, and Z-plate fixation by anterior approach. Many surgical methods were adopted to treat acute burst thoracolumbar fracture. But the optimal surgical management remains controversial. A retrospective review of a consecutive series of 48 patients with thoracolumbar burst fracture treated with anterior corpectomy, titanic mesh autograft, and Z-plate internal fixation was carried out. Preoperative clinical and radiographic data of all cases were originally collected. Surgical indications were motor neurologic deficit and thoracolumbar column instability. Twenty-two patients (45.8%) with acute thoracolumbar burst fractures presented with a neurologic deficit. The postoperative recovery of neural function, restoration of anterior cortex collapse, kyphotic angle, and spinal canal compromise were observed. The preoperative kyphotic angle was improved to a mean of 5.6°, radiographic height restored to 95.8% of the adjacent normal levels, and canal compromise was 0%. None of the patients had neurologic deterioration. Mean follow-up time was 32.4 months (range, 24-47 months). All 22 patients with neurologic deficit demonstrated at least one Frankel grade improvement on final observation, with 16 (73%) patients had accomplished complete neurologic recovery. Forty-six (96%) patients reported minimal or no pain at final follow-up observation, and 40 (83%) patients who had been working before injury returned to original work. The authors considered spinal cord decompression with anterior corpectomy and stability reconstruction with titanic mesh autograft and Z-plate fixation at same time in one incision as an effective technique for unstable thoracolumbar burst fracture with and without neurologic deficit.

A Pitfall in Fixation of Distal Humeral Fractures with Pre-Contoured Locking Compression Plate

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Prakash Jayakumar

2015-04-01

Full Text Available Anatomically precontoured locking plates are intended to facilitate the fixation of articular fractures and particularly those associated with osteoporosis. Fractures of the distal humerus are relatively uncommon injuries where operative intervention can be exceptionally challenging. The distal humeral trochlea provides a very narrow anatomical window through which to pass a fixed-angle locking screw, which must also avoid the olecranon, coronoid, and radial fossae. We describe 3 patients (ages 27, 49, and 73 years with a bicolumnar fracture of the distal humerus where very short distal locking screws were used. Intra-articular screw placement was avoided but loss of fixation occurred in two patients and a third was treated with a prolonged period of immobilization. We postulate that fixed-angle screw trajectories may make it difficult for the surgeon to place screws of adequate length in this anatomically confined region, and may lead to insufficient distal fixation. Surgical tactics should include placement of as many screws as possible into the distal fragment, as long as possible, and that each screw pass through a plate without necessarily locking in.

Trochanteric Fixation With a Third-Generation Cable-Plate System: An Independent Experience.

Science.gov (United States)

Stewart, Andrew D; Abdelbary, Hesham; Beaulé, Paul E

2017-09-01

Greater trochanteric fracture/nonunion can be a devastating complication with significant functional impact after total hip arthroplasty, and their fixation remains a challenge because of the significant forces being transmitted as well as the poor bone quality often associated with these fractures. The objective of this study is to investigate the rates of reoperation and trochanteric nonunion using a third-generation cable-plate system at one center. Thirty-five patients, mean age 72.9 years (range 46-98 years) with 24 women and 11 men, underwent fixation of their fractured greater trochanter using a third-generation cable-plate system. The indications were: periprosthetic fracture (n = 17), complex primary arthroplasty (n = 5), and complex revision arthroplasty (n = 13). Primary outcomes included rates of reoperation and radiographic union. At a mean follow-up of 2.5 years, trochanteric union rate was 62.9% with nonunion rate of 31.4%, and fibrous union in 5.7%. In regard to quality of initial apposition, only 40% achieved a perfect bone on bone reduction. Ten patients (28.6%) had evidence of wire breakage. Five patients (14.3%) required reoperation and removal of the internal fixation because of lateral hip pain. Fixation of the trochanteric fractures remains a challenge with a relatively high reoperation rate. Poor bone quality and capacity to maintain a stable reduction continue to make this complication after total hip arthroplasty a difficult problem to solve. Copyright © 2017. Published by Elsevier Inc.

Distal tibial fracture treated by minimally invasive plate osteosynthesis after external fixation Retrospective clinical and radiographic assessment

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Al. Șerban

2014-02-01

Full Text Available Fractures of the horizontal surface of the distal tibia are known commonly as pylon or plafond fractures, and represent 1-5% of lower extremity fractures, 7-10% of all tibial fractures. The protocol consisted of immediate (within eight to 24 hours open reduction and internal fixation of the fibula, using a fibular plate or one third tubular plate and application of an external fixator spanning the ankle joint. In the second stage, the treatment of proximal and distal tibial fractures with close reduction and MIPPO technique can preserve soft tissue, simplify operative procedure and decrease wound, obtain rigid internal fixation and guarantee early function exercises of ankle joint. In this study we evaluated 22 patients treated in Clinical Emergency Hospital Constanta between April 2012 - July 2013 diagnosed with multifragmentary fractures of the distal tibia. This study evaluates the treatment of complex fractures of distal tibia with locked plate after external fixation. There were 17 males and 5 females of mean age 51,7 years (31-68. The mean follow-up period was 14 weeks. (Ranging from 9-16 weeks. All patients were fully weight bearing at 16 weeks (ranging 9-16 weeks showing radiological union. There were no cases of failures of fixation, or rotational misalignment. No significant complication was observed in our patients. MIPO is an effective method of treatment for distal tibial fractures, reduce surgical trauma and maintain a more biologically favorable environment for fracture healing, reducing risks of infection and nonunion.

Locking internal fixator with minimally invasive plate osteosynthesis for the proximal and distal tibial fractures

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TONG Da-ke

2012-02-01

Full Text Available 【Abstract】Objective: To investigate the efficacy of the locking internal fixator (LIF, which includes the locking compression plate (LCP and the less invasive stable system (LISS, in the proximal and distal tibial fractures. Methods: We did a retrospective study on a total of 98 patients with either proximal or distal tibial fractures from January 2003 to January 2007, who had received the opera- tion with LIF by the minimally invasive plate osteosynthesis (MIPO technique. The data consisted of 43 proximal tibial fractures (type AO41C3 and 55 distal tibial fractures (type AO43C3. Results: No complications were observed in all patients after operation. The mean healing time was 8.4 months (range 5-14 months. Only two cases of delayed union occurred at postoperative 10 months. No infections were reported after the definitive surgery even in the cases of open fractures. All patients reached a full range of motion at postoperative 6 to 9 months and regained the normal functions of knee and ankle joints. Conclusion: Using LIF in MIPO technique is a reliable approach towards the proximal and distal tibial fractures that are not suitable for intramedullary nailing. Key words: Internal fixator; Tibial fractures; Fracture fixation, intramedullary; Bone plates

Alternative technique of cervical spinal stabilization employing lateral mass plate and screw and intra-articular spacer fixation

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Atul Goel

2013-01-01

Full Text Available Aim: The author discusses an alternative technique of segmental cervical spinal fixation. Material and Methods: The subtleties of the technique are discussed on the basis of experience with 3 cases with a follow-up of between 30 and 36 months. Technique: The technique involves debridement of facetal articular cartilage, distraction of facets, jamming of ′Goel spacer′ into the articular cavity and fortification of the fixation by lateral mass plate and screw fixation. The ′double-insurance′ method of fixation is safe for vertebral artery, nerve roots and spinal neural structures and the fixation is strong. Conclusions: The discussed technique is safe and provides a strong fixation and a ground for ultimate arthrodesis.

Unstable metacarpal and phalangeal fractures: treatment by internal fixation using AO mini-fragment plates and screws.

Science.gov (United States)

Mumtaz, Mohammad Umar; Farooq, Muneer Ahmad; Rasool, Altaf Ahmad; Kawoosa, Altaf Ahmad; Badoo, Abdul Rashid; Dhar, Shabir Ahmad

2010-07-01

Accurate open reduction and internal fixation for metacarpal and phalangeal fractures of the hand is required in less than 5% of the patients; otherwise, closed treatment techniques offer satisfactory results in most of these cases as these fractures are stable either before or after closed reduction. AO mini-fragment screws and plates, when used in properly selected cases, can provide rigid fixation, allowing early mobilization of joints and hence good functional results while avoiding problems associated with protruding K-wires and immobilization. The advantages of such internal fixation urged us to undertake such a study in our state where such hand injuries are commonly seen. Forty patients with 42 unstable metacarpal and phalangeal fractures were treated with open reduction and internal fixation using AO mini-fragment screws and plates over a period of three years in a prospective manner. The overall results were good in 78.5% of cases, fair in 19% of cases and poor in 2.5% of cases, as judged according to the criteria of the American Society for Surgery of the Hand. This technique is a reasonable option for treating unstable metacarpal and phalangeal fractures as it provides a highly rigid fixation, which is sufficient to allow early mobilization of the adjacent joints, thus helping to achieve good functional results.

Analysis of clinical efficacy and complications of titanium mini plate internal fixation and reconstructive surgery for patients with orbital fracture

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Yang Liu

2016-07-01

Full Text Available AIM: To analyze the clinical efficacy and complications of titanium mini plate internal fixation and reconstructive surgery for patients with orbital fracture. METHODS: Fifty-seven cases(60 eyeswith orbital fracture from March 2013 to April 2014 in our hospital were researched. According to the random number table method, the patients were divided into observation group(29 cases with 30 eyesand control group(28 cases with 30 eyes. The control group was treated with hydroxyapatite artificial bone plate for internal fixation, and the observation group with titanium mini plate internal fixation and reconstructive surgery. The diplopia grading, grading of ocular movement disorder before and at 1, 3mo after treatment and postoperative complications(prolapse, dislocation, infectionwere compared between the two groups. RESULTS: In both group, all the 60 eyes were healed without scar formation. The rate of diplopia grading as grade 0 1mo postoperatively of observation group and the control groups were 63% and 40%(PPPCONCLUSION: The clinical curative effect of titanium mini plate internal fixation and reconstructive surgery has a good effect for orbital fractures, which can improve the therapeutic effect and reduce the incidence of adverse reactions.

Locking plate fixation provides superior fixation of humerus split type greater tuberosity fractures than tension bands and double row suture bridges.

Science.gov (United States)

Gaudelli, Cinzia; Ménard, Jérémie; Mutch, Jennifer; Laflamme, G-Yves; Petit, Yvan; Rouleau, Dominique M

2014-11-01

This paper aims to determine the strongest fixation method for split type greater tuberosity fractures of the proximal humerus by testing and comparing three fixation methods: a tension band with No. 2 wire suture, a double-row suture bridge with suture anchors, and a manually contoured calcaneal locking plate. Each method was tested on eight porcine humeri. A osteotomy of the greater tuberosity was performed 50° to the humeral shaft and then fixed according to one of three methods. The humeri were then placed in a testing apparatus and tension was applied along the supraspinatus tendon using a thermoelectric cooling clamp. The load required to produce 3mm and 5mm of displacement, as well as complete failure, was recorded using an axial load cell. The average load required to produce 3mm and 5mm of displacement was 658N and 1112N for the locking plate, 199N and 247N for the double row, and 75N and 105N for the tension band. The difference between the three groups was significant (Prow (456N) and tension band (279N) (Prow (71N/mm) and tension band (33N/mm) (Pbiomechanical fixation for split type greater tuberosity fractures. Copyright © 2014 Elsevier Ltd. All rights reserved.

Use of locking plates for fixation of the greater trochanter in patients with hip replacement

Directory of Open Access Journals (Sweden)

Allison K. Tetreault, BA

2016-12-01

Conclusions: Locking plate technology is a successful method of fixation of the greater trochanter in patients with THA. Postoperative trochanteric pain and reoperation for hardware-related issues remain a challenge.

First Metatarsophalangeal Joint Arthrodesis: A Retrospective Comparison of Crossed-screws, Locking and Non-Locking Plate Fixation with Lag Screw

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Leif Claassen

2017-07-01

Full Text Available Background:Locking plate fixation is increasingly used for first metatarsophalangeal joint (MTP-I arthrodesis. Still there is few comparable clinical data regarding this procedure. Methods:We retrospectively evaluated 60 patients who received an arthrodesis of the MTP-I between January 2008 and June 2010. With 20 patients each we performed a locking plate fixation with lag screw, arthrodesis with crossed-screwsor with a nonlocking plate with lag screw. Results: There were four non-unions in crossed-screws patients and one nonunion in non-locked plate group. All the patients in locking plate group achieved union. 90% of the patients were completely or mildly satisfied in locking plate group, whereas this rate was 80% for patients in both crossed screws and non-locking plate groups. Conclusions: Use of dorsal plating for arthrodesis of MTP1 joint either locking or non-locking were associated with high union rate and acceptable and comparable functional outcome. Although nonunion rate was high using two crossed screws but functional outcome was not significantly different compare to dorsal plating. Level of evidence:Ш, retrospective comparative study

Use of tranexamic acid in dynamic hip screw plate fixation for trochanteric fractures.

Science.gov (United States)

Baruah, Ranjit Kumar; Borah, Pranab Jyoti; Haque, Russel

2016-12-01

To evaluate perioperative blood loss and blood transfusion requirement in patients who underwent dynamic hip screw plate fixation for a stable trochanteric fracture with or without preoperative intravenous tranexamic acid (TXA). 49 men and 11 women (mean age, 56.5 years) who underwent open reduction and internal fixation with a dynamic hip screw plate for a stable trochanteric fracture by a single surgeon were equally randomised to receive either a single dose of intravenous TXA (15 mg/kg) 15 minutes prior to surgery or an equal volume of normal saline by slow infusion. Intra- and post-operative blood loss and the need for blood transfusion were assessed, as was any thromboembolic adverse event. The TXA and control groups were comparable in terms of age, gender, body mass index, blood pressure, pulse rate, time from injury to surgery, operating time, and preoperative haematological data. Blood loss was lower in the TXA than control group intraoperatively (320.3 vs. 403.33 ml, ptrochanteric fractures.

C-2 anterior plate-screw fixation: a quantitative anatomical and morphometric evaluation.

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Senoglu, M; Ozbag, D; Gumusalan, Y

2010-01-01

Discectomy and inter-vertebral body fusion combined with the anterior plate-screw fixa tion is the common procedure in cervical spine surgery. But the anterior plate-screw fixation of the C2 spine has been the uncommon surgical procedure. In this study, we analyze the anatomy of the C2 body relevant to C2 anterior plate-screw fixation. Eighty-six dried C2 spines were evaluated directly for this study. Measurements were made on the C2 body width and midsagittal anteroposterior (AP) depth and the anteroposterior parasagittal depth 5 mm lateral to midline on the inferior endplates, in addition to on the middle body. Measurements also were made of anteroposterior parasagittal vertebral depth with both medial and lateral inclination of 10 degrees, with respect to the parasagittal plane of the vertebral body. The ideal maximum screw length and trajectory was found to be AP medial parasagittal depth of inferior surface of the C2 body [Right: 13.7 +/- 1.4 mm (11.0-17.9), Left: 13.6 +/- 1.5 mm (10.7-17.8)]. We report the measurements of the vertebral body of the C2. We think these measurements provide guidelines for operating on the anterior C2 spine, and enhance the confidence interval for the surgeon (Tab. 3, Fig. 1, Ref. 24).

Distraction osteogenesis using combined locking plate and Ilizarov fixator in the treatment of bone defect: A report of 2 cases

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John Mukhopadhaya

2017-01-01

Full Text Available Distraction osteogenesis and bone transport has been used to reconstruct bone loss defect by allowing new bone to form in the gap. Plate-guided bone transport has been successfully described in literature to treat bone loss defect in the femur, tibia, and mandible. This study reports two cases of fracture of femur with segmental bone loss treated with locking plate fixation and bone transport with Ilizarov ring fixator. At the time of docking, when the transport segment is compressed with bone fragment, the bone fragment is fixed with additional locking or nonlocking screws through the plate. The bone defect size was 7 cm in case 1 and 8 cm in case 2 and the external fixation indexes were 12.7 days/cm and 14 days/cm. No shortening was present in either of our cases. The average radiographic consolidation index was 37 days/cm. Both cases achieved infection-free bone segment regeneration and satisfactorily functional outcome. This technique reduces the duration of external fixation during the consolidation phase, allows correction of length and alignment and provides earlier rehabilitation.

Novel use of hand fracture fixation plates in the surgical stabilisation of flail chest.

LENUS (Irish Health Repository)

Dunlop, Rebecca L E

2010-01-01

Plastic surgeons specialize in working closely with other surgical colleagues to help solve clinical problems. In this case, we performed surgical stabilisation of a large flail chest fragment in conjunction with the cardiothoracic surgical team, using the mini-plating set more commonly used for hand fracture fixation. The use of this fixation system for flail chest has not previously been described, but offers advantages over other reported methods, primarily by dispensing with the need for an extensive thoracotomy incision and by providing robust stabilisation without the presence of prominent hardware.

To evaluate the efficacy of biodegradable plating system for fixation of maxillofacial fractures: A prospective study.

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Bali, Rishi K; Sharma, Parveen; Jindal, Shalu; Gaba, Shivani

2013-07-01

The present study was undertaken to evaluate the efficacy of biodegradable plating system for fixation of maxillofacial fractures and to study the morbidity associated with the use of biodegradable plates and screws. This prospective study consisted of 10 patients with maxillofacial fractures requiring open reduction and internal fixation. Fractures with infection, comminuted and pathological fractures were excluded. All were plated with biodegradable system (Inion CPS) using standard plating principles and observed for a total period of 24 weeks. Characteristics of the fractures, ease of use of bioresorbable plate/screw system and post operative complications were assessed. Of total 10 patients, eight patients were of midface fracture and two pediatric patients with mandibular fracture, with nine male and one female. The mean age was 32.8 years. Out of 20 plates and 68 screws applied to the 10 fractures sites; there were three incidences of screw breakage with no other intraoperative difficulties. Paresthesia of the infraorbital nerve was present in two patients, and recovered completely in four weeks after surgery. Fracture reduction was considered to be satisfactory in all cases. One patient developed postsurgical infection and was managed with oral antibiotics and analgesics. Favorable healing can be observed through the use of biodegradable plates and screws to stabilize selected midface fractures in patients of all ages, as well as mandible fractures in early childhood, however further studies with more sample size are required.

Clinical comparative analysis on unstable pelvic fractures in the treatment with percutaneous sacroiliac screws and sacroiliac joint anterior plate fixation.

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Li, C-L

2014-01-01

To investigate clinical efficacy of unstable pelvic fractures in the treatment with percutaneous sacroiliac screws and sacroiliac joint anterior plate fixation. 64 patients with unstable pelvic fractures were selected in the hospital from January 2008 to June 2011, and were randomly divided into two groups.(32 patients with sacroiliac anterior plate fixation as the control group, and another 32 patients with percutaneous sacroiliac screw internal fixation as the observation group). The perioperative period clinical indicators, postoperative Matta score, postoperative Majeed function score of all patients were compared and analyzed. The operation time, intraoperative blood loss, wound total length, postoperative fever time, duration of hospitalization in the observation group were significantly less than those in the control group. The complication rate (3.1%) in the observation group was lower than that in the control group (21.9%). The rate of Matta score excellent (96.9%) in the observation group was higher than that in the control group (81.2%) after the treatment. The rate of Majeed function score excellent (93.8%) in the observation group was significantly higher than that in the control group (75%) after the treatment. Percutaneous sacroiliac screw internal fixation in the treatment of unstable pelvic fractures has less injury, less bleeding, less pain and rapid recovery which is a safe and effective minimally invasive operation method. The clinical curative effect of percutaneous sacroiliac screw internal fixation is better than anterior plate fixation for the treatment of sacroiliac joint. The full preparation before the surgery and patients with positive can substantially reduce the occurrence of complications rate.

[Extramedullary fixation combined with intramedullary fixation in the surgical reduction of sagittal mandibular condylar fractures].

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Chuanjun, Chen; Xiaoyang, Chen; Jing, Chen

2016-10-01

This study aimed to evaluate the clinical effect of extramedullary fixation combined with intramedullary fixation during the surgical reduction of sagittal mandibular condylar fractures. Twenty-four sagittal fractures of the mandibular condyle in18 patients were fixed by two appliances: intramedullary with one long-screw osteosynthesis or Kirschner wire and extramedullary with one micro-plate. The radiologically-recorded post-operative stability-associated com-plications included the screw/micro-plate loosening, micro-plate twisting, micro-plate fractures, and fragment rotation. The occluding relations, the maximalinter-incisal distances upon mouth opening, and the mandibular deflection upon mouth opening were evaluated based on follow-up clinical examination. Postoperative panoramic X-ray and CT scans showed good repositioning of the fragment, with no redislocation or rotation, no screw/plate loosening, and no plate-twisting or fracture. Clinical examination showed that all patients regained normal mandibular movements, ideal occlusion, and normal maximal inter-incisal distances upon mouth opening. Extramedullary fixation combined with intramedullary fixation is highly recommended for sagittal condylar fractures because of the anti-rotation effect of the fragment and the reasonable place-ment of the fixation appliances.

Fragment-Specific Fixation Versus Volar Locking Plates in Primarily Nonreducible or Secondarily Redisplaced Distal Radius Fractures: A Randomized Controlled Study.

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Landgren, Marcus; Abramo, Antonio; Geijer, Mats; Kopylov, Philippe; Tägil, Magnus

2017-03-01

To compare the patient-reported, clinical, and radiographic outcome of 2 methods of internal fixation in distal radius fractures. Fifty patients, mean age 56 years (range, 21-69 years) with primarily nonreducible or secondarily redisplaced distal radius fractures were randomized to open reduction internal fixation using volar locking plates (n = 25) or fragment-specific fixation (n = 25). The patients were assessed on grip strength, range of motion, patient-reported outcome (Quick Disabilities of the Arm, Shoulder, and Hand), pain (visual analog scale), health-related quality of life (Short Form-12 [SF-12]), and radiographic evaluation. Grip strength at 12 months was the primary outcome measure. At 12 months, no difference was found in grip strength, which was 90% of the uninjured side in the volar plate group and 87% in the fragment-specific fixation group. No differences were found in range of motion and the median Quick Disabilities of the Arm, Shoulder, and Hand score was 5 in both groups. The overall complication rate was significant, 21% in the volar locking plate group, compared with 52% in the fragment-specific group. In treatment of primarily nonreducible or secondarily redisplaced distal radius fractures, volar locking plates and fragment-specific fixation both achieve good and similar patient-reported outcomes, although more complications were recorded in the fragment-specific group. Therapeutic II. Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Electrodepositions on Tantalum in Alkali Halide Melts

DEFF Research Database (Denmark)

Barner, Jens H. Von; Jensen, Annemette Hindhede; Christensen, Erik

2013-01-01

Surface layers of tantalum metal were electrodeposited on steel from K2TaF7-LiF-NaF-KF melts. With careful control of the oxide contents dense and adherent deposits could be obtained by pulse plating. In NaCl-KCl-NaF-Na2CO3 and NaCl-KCl-Na2CO3 melts carbonate ions seems to be reduced to carbon in...

Electrodepositions on Tantalum in alkali halide melts

DEFF Research Database (Denmark)

Barner, Jens H. Von; Jensen, Annemette Hindhede; Christensen, Erik

2012-01-01

Surface layers of tantalum metal were electrodeposited on steel from K 2TaF7-LiF-NaF-KF melts. With careful control of the oxide contents dense and adherent deposits could be obtained by pulse plating. In NaCl-KCl-NaF-Na2CO3 and NaCl-KCl-Na2CO 3 melts carbonate ions seems to be reduced to carbon ...

Vapor deposition of tantalum and tantalum compounds

International Nuclear Information System (INIS)

Trkula, M.

1996-01-01

Tantalum, and many of its compounds, can be deposited as coatings with techniques ranging from pure, thermal chemical vapor deposition to pure physical vapor deposition. This review concentrates on chemical vapor deposition techniques. The paper takes a historical approach. The authors review classical, metal halide-based techniques and current techniques for tantalum chemical vapor deposition. The advantages and limitations of the techniques will be compared. The need for new lower temperature processes and hence new precursor chemicals will be examined and explained. In the last section, they add some speculation as to possible new, low-temperature precursors for tantalum chemical vapor deposition

[Treatment type C fracture of the distal radius with locking compression plate and external fixators].

Science.gov (United States)

Yang, Xiang; Zhao, You-ming; Chen, Lin; Ye, Cong-cong; Guo, Wei-jun; Wang, Bo

2013-12-01

To compare efficacy of unilateral external fixators and locking compression plates in treating type C fractures of the distal radius. From January 2009 to June 2010, 76 patients with distal radius fracture were treated with LCP and external fixators, 54 patients were followed up. Among them, 29 cases were male and 25 cases were female with an average age of 45.31 (ranged, 24 to 68) years old. There were 29 patients in LCP group. According to AO classification, 8 cases were type C1, 7 cases were type C2 and 14 cases were type C3. There were 25 cases in external fixators group. According to AO classification, 6 cases were type C1, 8 cases were type C2 and 11 cases were type C3. Radial height, volar tilt and radial inclination were compared, advanced Gartland-Werley scoring were used to assessed wrist joint function after 6 and 12 months' following up. Two cases were suffered from nail infection in external fixators group. Fifty-four patients were followed up from 12 to 24 months with an average of 21.3 months. Radial height was (9.60 +/- 0.72) mm, volar tilt was (9.55 +/- 0.80) degrees and radial inclination was (21.40 +/- 0.78) degrees in LCP group,while those were (9.40 +/- 0.70) mm, (9.47 +/- 0.71) degrees and (21.20 +/- 0.73) degrees in external fixtors group, and with no statistical significance (P>0.05). Advanced Gartland-Werley score after 6 months' following up was 3.31 +/- 1.17 in LCP group, 5.56 +/- 1.58 in external fixtors group, and with significant difference (t=-5.99,Pmeaning (t=-1.55, P>0.05). LCP and external fixtors can receive good curative effects in treating type C distal radius fracture, and LCP can obtain obviously short-term efficacy, while there is no significant difference between two groups in long-term results. For serious distal radius comminuted fracture which unable to plate internal fixation, external fixators is a better choice.

[EFFECTIVENESS COMPARISON OF CORACOCLAVICULAR LIGAMENT RECONSTRUCTION BETWEEN BY AUTOLOGOUS AND ALLOGENEIC TENDON GRAFTS COMBINED WITH HOOK PLATE FIXATION FOR TREATING ACROMIOCLAVICULAR JOINT DISLOCATION].

Science.gov (United States)

Yin, Fei; Sun, Zhenzhong; Wei, Xuming; Liu, Xueguang; Zhou, Ming; Zhuang, Yin; Song, Sheng

2016-05-08

To compare the effectiveness of coracoclavicular ligament reconstruction between by using autologous plantaris tendon graft combined with hook plate fixation and allogeneic tendon graft combined with hook plate fixation for treating acromiocavicular joint dislocation. Thirty-three patients with acromioclavicular joint dislocation who accorded with the inclusion criteria between January 2013 and June 2014 were assigned into 2 groups. The patients were treated with autologous plantaris tendon graft combined with hook plate fixation in group A ( n =17), and with allogeneic tendon graft combined with hook plate fixation in group B ( n =16). Thirteen-one patients was followed up more than 12 months (15 in group A and 16 in group B). There was no significant difference in gender, age, cause of injury, sides, time between injury and surgery, and type of dislocation ( P >0.05). The assessments included operation time, hospitalization time, hospitalization expenses, shoulder range of motion, gap of acromioclavicular, Constant-Murley scores, and visual analogue scale (VAS) for pain. The operation time of group A was significantly longer than that of group B, and the hospitalization expense was significantly lower than that of group B ( P 0.05). No redislocation of acromioclavicular joint and rejection reaction occurred during follow-up. At last follow-up, there was no significant difference in shoulder range of motion, Constant-Murley score, and VAS score between 2 groups ( P >0.05). Coracoclavicular ligament reconstruction by autologous plantaris tendon or allogeneic tendon graft combined with hook plate fixation for the treatment of acromioclavicular joint dislocation can achieve good effectiveness. The appropriate treatment should be chosen according to the patient's economic situation.

History of internal fixation (part 1): early developments with wires and plates before World War II.

Science.gov (United States)

Hernigou, Philippe; Pariat, Jacques

2017-06-01

Though the date at which an orthopaedic implant was first used cannot be ascertained with any certainty, the fixation of bone fracture using an iron wire was reported for the first time in a French manuscript in 1775. The first techniques of operative fracture treatment were developed at the end of the 18th and in the beginning of the 19th centuries. The use of cerclage wires to fix fractures was the most frequent fixation at this time. The French Berenger-Feraud (1832-1900) had written the first book on internal fixation. However internal fixation of fractures could not become a practical method before Lister had ensured the safety of open reduction and internal fixation in the treatment of fractures. Lister is not only the father of asepsis; he also used metal wires to fix even closed fractures. The first internal fixation by means of a plate and screws was described by Carl Hansmann in 1858 in Hamburg. Nevertheless, Arbuthnot Lane (1892) and Albin Lambotte (1905) are considered to be the founders of this method, which was further developed by Sherman in the first part of the 20th century.

Fixation via dorsal for complex fractures of radius distal with plate P

International Nuclear Information System (INIS)

Rojas, Sandra; Bocanegra, Sergio; Suarez, Fabio

2002-01-01

The existence of multiple alternatives in the handling of the complex fractures of the radius distal it constitutes a reflection of the challenge that these they represent as for the possibility of recovering an appropriate consistency to articulate and orientation and radial height. This prospective study included 13 patients assisted in the hospital military of Bogota, by means of internal fixation with plate π. This treatment alternative, it solves many present inconveniences with other methods and it allows the precocious postoperative rehabilitation

Medial Calcar Support and Radiographic Outcomes of Plate Fixation for Proximal Humeral Fractures

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Shih-Jie Lin

2015-01-01

Full Text Available Plate fixation remains one of the most popular surgical procedures for treating proximal humeral fractures (PHFx; however, substantial rates of complications have been reported in the literature. The objectives of the study were to examine how medial calcar support (MCS affects the radiographic outcomes and to determine the prognostic factors predicting treatment failure. We performed a retrospective cohort study of 89 adult patients who had PHFx and were treated with plate fixation at our institution in 2007–2011. The enrolled patients were separated into two groups according to disruption of medial calcar. Our results revealed an increased rate of poor radiographic outcomes in patients with disrupted medial calcar. Osteonecrosis of the humeral head and redisplacement were the two radiographic outcomes which had a positive causality with disruption of medial calcar (P=0.008 and 0.050, resp.. Deficient medial calcar, inadequate reduction, diabetes mellitus, chronic kidney disease, and chronic liver disease were all significant predictors for the development of osteonecrosis in patients after PHFx surgery. Inadequate reduction was also a predictor for redisplacement. We confirmed that the restoration of medial calcar as well as comorbid conditions plays key roles in treatment of patients having PHFx with disrupted medial calcar.

Comparative study of bridge plate associated to the intramedullary pin and the dynamic compression plate on the experimental osteotomy fixation of femoral in rabbits (Oryctolagus cuniculus). Clinical, radiographic, histological and scintigraphy analyses

International Nuclear Information System (INIS)

Borges, Natalie Ferreira

2011-01-01

The objectives were to benchmark and monitor the fracture healing of femoral osteotomy in rabbits after fixation with dynamic compression plate and bridge plate associated with intramedullary pin. Were used 14 New Zealand rabbits, four months old with mean weight of 3.5 pounds, from the Experimental Farm Professor Helio Barbosa of the Veterinary School of Minas Gerais Federal Univ. (UFMG). The animals were randomly divided into two groups (I and II). All rabbits underwent osteotomy across the middle third of right femur. In the group I was made to fix the osteotomy with the bridge plate (BP) associated with intramedullary pin, introduced the technique of minimal invasion. In group II, we used dynamic compression plate (DCP) via the conventional approach. Both groups were evaluated clinical, radiographic, histologic and scintigraphic findings. Clinical assessments were performed weekly until the 12 th postoperative week and radiographic examinations were performed before, immediately after, at 15, 30, 45, 60 and 90 days. The bone scintigraphy were performed before and at 20, 50 and 90 days after surgery to monitor the bone metabolism qualitatively and quantitatively. Observed perfusion and bone healing process. After 90 days of study, there was histopathologic evaluation of the osteotomized area and the insertion of screws. In the region of the osteotomy was observed predominance of trabecular bone in group I and group II, the predominance of bone osteons, compatible with the original bone. On insertion of the screws did not differ between groups and there was cortical discontinuity, little necrosis and local hemorrhage. The two types of fixation have led to consolidation within the scheduled period, maturing in early fixation with DCP fixation compared with BP. Scintigraphy demonstrated by the indices of activity and image characteristics, the process of bone healing was significantly greater in animals undergoing early fixation with DCP. (author)

Treatment of unstable fractures, dislocations and fracture-dislocations of the cervical spine with Senegas plate fixation

NARCIS (Netherlands)

Moerman, J.; Harth, A.; Trimpont, van I.; Uyttendaele, D.; Verdonk, R.; Claessens, H.A.; Verbeke, S.

1994-01-01

The results of the anterior approach to the cervical spine for the treatment of fractures and dislocations by arthrodesis and Senegas plate fixation are described. Twenty-two patients underwent a one- or two-level arthrodesis of the cervical spine. Their mean age was 42 years. The injuries were

First Metatarsophalangeal Joint Arthrodesis in Hallux Valgus Versus Hallux Rigidus Using Cup and Cone Preparation Compression Screw and Dorsal Plate Fixation.

Science.gov (United States)

Chien, Calvin; Alfred, Terrence; Freihaut, Richard; Pit, Sabrina

2017-10-19

Various techniques have been described for first metatarsophalangeal (MTP) joint arthrodesis. The purpose of this study was to determine if cup and cone preparation by a single surgeon with an interfragmentary screw and dorsal plate fixation provides a comparable union rate in hallux valgus versus hallux rigidus. Our study included all patients who underwent first MTP joint fusions using cup and cone preparation with an interfragmentary compression screw and dorsal plate fixation from 2010 to 2015. We compared union rates in 65 patients with hallux rigidus with 47 who had hallux valgus. One of 65 hallux rigidus cases developed non-union and underwent revision surgery. One of 47 patients in the hallux valgus group developed a painless non-union. All other patients achieved union based on post operative radiographs. Our rate of painful non-union was 1.5% for hallux rigidus and 0% for hallux valgus, which is lower than recent published literature of 7% for hallux valgus and 3.7% for hallux rigidus. We found no difference between the two groups suggesting this method may provide stronger fixation and may be preferable when dealing with hallux valgus. First metatarsophalangeal joint fusion in patients with severe hallux valgus and hallux rigidus, using spherical reamers, compression screw and dorsal plate fixation is equally successful at achieving clinical and radiographic fusion in both hallux valgus and hallux rigidus.

Hook plate fixation for acute acromioclavicular dislocations without coracoclavicular ligament reconstruction: a functional outcome study in military personnel.

Science.gov (United States)

Kumar, Narinder; Sharma, Vyom

2015-08-01

The aim of our study was to evaluate the shoulder function after clavicular hook plate fixation of acute acromioclavicular dislocations (Rockwood type III) in a population group consisting exclusively of high-demand military personnel. This prospective study was carried out at a tertiary care military orthopaedic centre during 2012-2013 using clavicular hook plate for management of acromioclavicular injuries without coracoclavicular ligament reconstruction in 33 patients. All patients underwent routine implant removal after 16 weeks. The functional outcome was assessed at 3, 6 and 12 months after hook plate removal and 2 years from the initial surgery using the Constant Murley and UCLA Scores. All the patients were male serving soldiers and had sustained acromioclavicular joint dislocation (Rockwood type III). Mean age of the patient group was 34.24 years (21-55 years). The mean follow-up period in this study was 23.5 months (20-26 months) after hook plate fixation and an average of 19.9 months (17-22 months) after hook plate removal. The average Constant Score at 3 months after hook plate removal was 60.3 as compared to 83.7 and 90.3 at 6 months and 1 year, respectively, and an average of 91.8 at the last follow-up that was approximately 2 years after initial surgery which was statistically significant (p value acromioclavicular dislocations producing excellent medium-term functional results in high-demand soldiers.

Niobium and tantalum

Science.gov (United States)

Schulz, Klaus J.; Piatak, Nadine M.; Papp, John F.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

2017-12-19

Niobium and tantalum are transition metals that are almost always found together in nature because they have very similar physical and chemical properties. Their properties of hardness, conductivity, and resistance to corrosion largely determine their primary uses today. The leading use of niobium (about 75 percent) is in the production of high-strength steel alloys used in pipelines, transportation infrastructure, and structural applications. Electronic capacitors are the leading use of tantalum for high-end applications, including cell phones, computer hard drives, and such implantable medical devices as pacemakers. Niobium and tantalum are considered critical and strategic metals based on the potential risks to their supply (because current production is restricted to only a few countries) and the significant effects that a restriction in supply would have on the defense, energy, high-tech industrial, and medical sectors.The average abundance of niobium and tantalum in bulk continental crust is relatively low—8.0 parts per million (ppm) niobium and 0.7 ppm tantalum. Their chemical characteristics, such as small ionic size and high electronic field strength, significantly reduce the potential for these elements to substitute for more common elements in rock-forming minerals and make niobium and tantalum essentially immobile in most aqueous solutions. Niobium and tantalum do not occur naturally as pure metals but are concentrated in a variety of relatively rare oxide and hydroxide minerals, as well as in a few rare silicate minerals. Niobium is primarily derived from the complex oxide minerals of the pyrochlore group ((Na,Ca,Ce)2(Nb,Ti,Ta)2(O,OH,F)7), which are found in some alkaline granite-syenite complexes (that is, igneous rocks containing sodium- or potassium-rich minerals and little or no quartz) and carbonatites (that is, igneous rocks that are more than 50 percent composed of primary carbonate minerals, by volume). Tantalum is derived mostly from the

Open-wedge osteotomy using an internal plate fixator in patients with medial-compartment gonarthritis and varus malalignment

DEFF Research Database (Denmark)

Niemeyer, Philipp; Schmal, Hagen; Hauschild, Oliver

2010-01-01

PURPOSE: Our purpose was to evaluate the 3-year clinical results of patients with medial-compartment osteoarthritis of the knee and varus malalignment who underwent open-wedge high tibial osteotomy (HTO) with an internal plate fixator (TomoFix; Synthes, Solothurn, Switzerland). Clinical results a...

Radiographic healing and remodelling of cortical and cancellous bone grafts after rigid plate fixation

International Nuclear Information System (INIS)

Waris, P.; Karaharju, E.; Slaetis, P.; Paavolainen, P.

1980-01-01

Cortical and cancellous interposition grafts, with rigid plate fixation, in the tibiofibular bones of 130 rabbits were followed radiographically for one year. The cancellous grafts healed earlier, but by 12 weeks both graft types had been incorporated, the distal host-graft interface being the last to heal. Progressive cancellous transformation in both the graft and host bone led to an increased over-all bone diameter, a widened medullary canal and a thinned porotic wall. (Auth.)

Treatment of displaced talar neck fractures using delayed procedures of plate fixation through dual approaches.

Science.gov (United States)

Xue, Youdi; Zhang, Hui; Pei, Fuxing; Tu, Chongqi; Song, Yueming; Fang, Yue; Liu, Lei

2014-01-01

Treatment of talar neck fractures is challenging. Various surgical approaches and fixation methods have been documented. Clinical outcomes are often dissatisfying due to inadequate reduction and fixation with high rates of complications. Obtaining satisfactory clinical outcomes with minimum complications remains a hard task for orthopaedic surgeons. In the period from May 2007 to September 2010, a total of 31 cases with closed displaced talar neck fractures were treated surgically in our department. Injuries were classified according to the Hawkins classification modified by Canale and Kelly. Under general anaesthesia with sufficient muscle relaxation, urgent closed reduction was initiated once the patients were admitted; if the procedure failed, open reduction and provisional stabilisation with Kirschner wires through an anteromedial approach with tibiometatarsal external fixation were performed. When the soft tissue had recovered, definitive fixation was performed with plate and screws through dual approaches. The final follow-up examination included radiological analysis, clinical evaluation and functional outcomes which were carried out according to the Ankle-Hindfoot Scale of the American Orthopaedic Foot and Ankle Society (AOFAS), patient satisfaction and SF-36. Twenty-eight patients were followed up for an average of 25 months (range 18-50 months) after the injury. Only two patients had soft tissue complications, and recovery was satisfactory with conservative treatment. All of the fractures healed anatomically without malunion and nonunion, and the average union time was 14 weeks (range 12-24 weeks). Post-traumatic arthritis developed in ten cases, while six patients suffered from avascular necrosis of the talus. Secondary procedures included three cases of subtalar arthrodesis, one case of ankle arthrodesis and one case of total ankle replacement. The mean AOFAS hindfoot score was 78 (range 65-91). According to the SF-36, the average score of the

Mini-plate versus Kirschner wire internal fixation for treatment of metacarpal and phalangeal fractures in Chinese Han population: a meta-analysis.

Science.gov (United States)

Xu, Jiaming; Zhang, Changqing

2014-04-11

This meta-analysis aimed to compare the therapeutic effect of mini-plate versus Kirschner wire (K-wire) internal fixation on the treatment of metacarpal and phalangeal fractures among Chinese Han population. Databases of China National Knowledge Infrastructure (CNKI), Wanfang, Chinese VIP, PubMed, and Embase were retrieved for studies on mini-plate (case group) versus K-wire (control group) internal fixation for the treatment of metacarpal and phalangeal fractures among Chinese Han population. The odds ratio (OR) and standardized mean difference (SMD) at 95% confidence interval (CI) were used for estimating the effects of dichotomous data and continuous data, respectively. All statistical analyses were performed by Review Manager 5.2 software. A total of 18 studies involving 1,375 metacarpal or phalangeal fracture patients (709 cases and 666 controls) were included in the meta-analysis. There were significant differences in fracture healing time (SMD = -1.28; 95% CI: -1.81, -0.76), postoperative infection rate (OR = 0.25; 95% CI: 0.16, 0.39), complication incidence (OR = 0.24; 95% CI: 0.15, 0.38), and surgery time (SMD = 1.57; 95% CI: 0.76, 2.37) between the case and the control group, while no significant difference was found in hospital stays between these two groups (SMD = 0.43; 95% CI: -0.34, 1.20; P = 0.27). For the treatment of metacarpal or phalangeal fracture among Chinese Han population, mini-plate has advantages of shorter healing time and lower infection rate and complication incidence compared with K-wire internal fixation, while a longer surgery time than K-wire. In conclusion, mini-plate is prior than K-wire internal fixation for the treatment of metacarpal or phalangeal fracture among Chinese Han population.

Hydroxyapatite coatings of fracture fixation plates for orthopedic applications

International Nuclear Information System (INIS)

Omar, M.A.; Abdullah, N.S.; Yahya, N.M.; Subuki, I.; Hassan, N.; Mohamad, S.M.

2007-01-01

The plasma sprayed hydroxyapatite (HA) coatings are used on metallic implants to improve their adhesion to bone. The present study investigates the plasma sprayed process of HA on the fracture fixation plates fabricated by metal injection moulding process. The phase and microstructure of the coatings were studied and their microhardness measured. The phase composition of coatings was analyzed by the use of X-ray diffraction method. The homogeneity of the deposit and coating thickness were evaluated using scanning electron microscope (SEM). The results suggest that the nature of the coating morphology, phase and crystallinity changes with respect to the plasma sprayed processing parameters. The XRD revealed the presence of both amorphous and crystalline phases. In addition, the powder particles also melt partially in some region and coating microstructure varied from a porous structure to a smooth glassy structure or a typical lamellar structure. (author)

Zero-profile anchored cage reduces risk of postoperative dysphagia compared with cage with plate fixation after anterior cervical discectomy and fusion.

Science.gov (United States)

Xiao, ShanWen; Liang, ZhuDe; Wei, Wu; Ning, JinPei

2017-04-01

To compare the rate of postoperative dysphagia between zero-profile anchored cage fixation (ZPC group) and cage with plate fixation (CP group) after anterior cervical discectomy and fusion (ACDF). A meta-analysis of cohort studies between zero-profile anchored cage and conventional cage with plate fixation after ACDF for the treatment of cervical diseases from 2008 to May 2016. An extensive search of studies was performed in PubMed, Medline, Embase, Cochrane library and Google Scholar. Dysphagia rate was extracted. Data analysis was conducted with RevMan 5.2. Sixteen trials involving 1066 patients were included in this meta-analysis. The results suggested that the ZPC group were associated with lower incidences of dysphagia than the CP group at postoperative immediately, 2 weeks, 2, 3, 6 and 12 months. In subgroup analysis, although significant differences were only found in the mild dysphagia at 3 and 6 months postoperatively and in the moderate dysphagia at 2 weeks after surgery; the ZPC group had a lower rate of postoperative dysphagia than the CCP group in short, medium and long term follow-up periods. Zero-profile anchored cage had a lower risk of postoperative dysphagia than cage with plate.

Stability of radial head and neck fractures: a biomechanical study of six fixation constructs with consideration of three locking plates.

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Burkhart, Klaus Josef; Mueller, Lars P; Krezdorn, David; Appelmann, Philipp; Prommersberger, Karl J; Sternstein, Werner; Rommens, Pol M

2007-12-01

Open reduction and internal fixation of radial neck fractures can lead to secondary loss of reduction and nonunion due to insufficient stability. Nevertheless, there are only a few biomechanical studies about the stability achieved by different osteosynthesis constructs. Forty-eight formalin-fixed, human proximal radii were divided into 6 groups according to their bone density (measured by dual-energy x-ray absorptiometry). A 2.7-mm gap osteotomy was performed to simulate an unstable radial neck fracture, which was fixed with 3 nonlocking implants: a 2.4-mm T plate, a 2.4-mm blade plate, and 2.0-mm crossed screws, and 3 locking plates: a 2.0-mm LCP T plate, a 2.0-mm 6x2 grid plate, and a 2.0-mm radial head plate. Implants were tested under axial (N/mm) and torsional (Ncm/ degrees ) loads with a servohydraulic materials testing machine. The radial head plate was significantly stiffer than all other implants under axial as well as under torsional loads, with values of 36 N/mm and 13 Ncm/ degrees . The second-stiffest implant was the blade plate, with values of 20 N/mm and 6 Ncm/ degrees . The weakest implants were the 2.0-mm LCP, with values of 6 N/mm and 2 Ncm/ degrees , and the 2.0-mm crossed screws, with values of 18 N/mm and 2 Ncm/ degrees . The 2.4-mm T plate, with values of 14 N/mm and 4 Ncm/ degrees , and the 2.0-mm grid plate, with values of 8 N/mm and 4 Ncm/ degrees came to lie in the midfield. The 2.0-mm angle-stable plates-depending on their design-allow fixation with comparable or even higher stability than the bulky 2.4-mm nonlocking implants and 2.0-mm crossed screws.

Mini-Fragment Fixation Is Equivalent to Bicortical Screw Fixation for Horizontal Medial Malleolus Fractures.

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Wegner, Adam M; Wolinsky, Philip R; Robbins, Michael A; Garcia, Tanya C; Amanatullah, Derek F

2018-05-01

Horizontal fractures of the medial malleolus occur through application of valgus or abduction force through the ankle that creates a tension failure of the medial malleolus. The authors hypothesize that mini-fragment T-plates may offer improved fixation, but the optimal fixation construct for these fractures remains unclear. Forty synthetic distal tibiae with identical osteotomies were randomized into 4 fixation constructs: (1) two parallel unicortical cancellous screws; (2) two parallel bicortical cortical screws; (3) a contoured mini-fragment T-plate with 2 unicortical screws in the fragment and 2 bicortical screws in the shaft; and (4) a contoured mini-fragment T-plate with 2 bicortical screws in the fragment and 2 unicortical screws in the shaft. Specimens were subjected to offset axial tension loading on a servohydraulic testing system and tracked using high-resolution video. Failure was defined as 2 mm of articular displacement. Analysis of variance followed by a Tukey-Kramer post hoc test was used to assess for differences between groups, with significance defined as Pfragment T-plate constructs (239±83 N/mm and 190±37 N/mm) and the bicortical screw construct (240±17 N/mm) were not statistically different. The mean stiffness values of both mini-fragment T-plate constructs and the bicortical screw construct were higher than that of a parallel unicortical screw construct (102±20 N/mm). Contoured T-plate constructs provide stiffer initial fixation than a unicortical cancellous screw construct. The T-plate is biomechanically equivalent to a bicortical screw construct, but may be superior in capturing small fragments of bone. [Orthopedics. 2018; 41(3):e395-e399.]. Copyright 2018, SLACK Incorporated.

[Comparison study on locking compress plate external fixator and standard external fixator for treatment of tibial open fractures].

Science.gov (United States)

Wu, Gang; Luo, Xiaozhong; Tan, Lun; Lin, Xu; Wu, Chao; Guo, Yong; Zhong, Zewei

2013-11-01

To compare the clinical results of locking compress plate (LCP) as an external fixator and standard external fixator for treatment of tibial open fractures. Between May 2009 and June 2012, 59 patients with tibial open fractures were treated with LCP as an external fixator in 36 patients (group A), and with standard external fixator in 23 patients (group B). There was no significant difference in gender, age, cause of injury, affected side, type of fracture, location, and interval between injury and surgery between 2 groups (P > 0.05). The time of fracture healing and incision healing, the time of partial weight-bearing, the range of motion (ROM) of knee and ankle, and complications were compared between 2 groups. The incidence of pin-track infection in group A (0) was significantly lower than that in group B (21.7%) (P=0.007). No significant difference was found in the incidence of superficial infection and deep infection of incision, and the time of incision healing between 2 groups (P > 0.05). Deep vein thrombosis occurred in 5 cases of group A and 2 cases of group B, showing no significant difference (Chi(2)=0.036, P=0.085). All patients were followed up 15.2 months on average (range, 9-28 months) in group A, and 18.6 months on average (range, 9-47 months) in group B. The malunion rate and nonunion rate showed no significant difference between groups A and B (0 versus 13.0% and 0 versus 8.7%, P > 0.05); the delayed union rate of group A (2.8%) was significantly lower than that of group B (21.7%) (Chi(2)=5.573, P=0.018). Group A had shorter time of fracture healing, quicker partial weight-bearing, greater ROM of the knee and ankle than group B (P fracture, and has good patients' compliance, so it is helpful to do functional exercise, improve fracture healing and function recovery, and reduce the complication incidence.

Patient-specific distal radius locking plate for fixation and accurate 3D positioning in corrective osteotomy.

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Dobbe, J G G; Vroemen, J C; Strackee, S D; Streekstra, G J

2014-11-01

Preoperative three-dimensional planning methods have been described extensively. However, transferring the virtual plan to the patient is often challenging. In this report, we describe the management of a severely malunited distal radius fracture using a patient-specific plate for accurate spatial positioning and fixation. Twenty months postoperatively the patient shows almost painless reconstruction and a nearly normal range of motion.

Fixation of displaced subcapital femoral fractures. Compression screw fixation versus double divergent pins.

Science.gov (United States)

Christie, J; Howie, C R; Armour, P C

1988-03-01

One hundred and twenty-seven consecutive patients with displaced subcapital fractures of the femoral neck (Garden Grade III or IV) all under 80 years of age and independently mobile, were randomly allocated to fixation with either double divergent pins or a single sliding screw-plate device. The incidence of non-union and infection in the sliding screw-plate group was significantly higher, and we believe that when internal fixation is considered appropriate multiple pinning should be used. Mobility after treatment was disappointing in about half of the patients, and we feel that internal fixation can only be justified in patients who are physiologically well preserved and who maintain a high level of activity.

COMPUTER-AIDED OPTIMIZATION OF CHOICE AND POSITIONING OF BONE PLATES AND SCREWS USED FOR INTERNAL-FIXATION OF MANDIBULAR FRACTURES

NARCIS (Netherlands)

ROZEMA, FR; BOS, RRM; BOERING, G; VANWILLIGEN, JD

1992-01-01

The present study describes a biomechanical integrated model of the mandibular system in which the maxilla and mandible, the masticatory muscles, and the temporomandibular joints are regarded as one system. In this model, strains in plate-osteosynthesis devices for internal fixation of mandibular

Role of Appositional Screw Fixation in Minimally Invasive Plate Osteosynthesis for Distal Tibial Fracture.

Science.gov (United States)

Yang, Kyu-Hyun; Won, Yougun; Kang, Dong-Hyun; Oh, Jin-Cheol; Kim, Sung-Jun

2015-09-01

To determine the effect of interfragmentary appositional (gap-closing) screw fixation in minimally invasive plate osteosynthesis (MIPO) for distal tibial fractures on the clinical and radiologic results. Prospective nonrandomized study. Level I trauma center. Sixty patients who were diagnosed as distal metadiaphyseal oblique or spiral tibial fracture without displaced articular fragment. Thirty patients (group A) of the 60 patients were treated with MIPO without appositional screw fixation, and the other 30 (group B) were treated with the screw. Radiologic union, clinical union, clinical functional score [American Orthopaedic Foot and Ankle Society (AOFAS) score], and complications. The time for initial callus formation and radiologic union was significantly longer in group A than those in group B (76.8 vs. 58.0 days, P = 0.044; 409 vs. 258.7 days, P = 0.002, respectively). The rate of clinical union during 1 year was significantly higher in group B than in group A (P = 0.0063). Four nonunion patients in group A achieved bone union after placement of an additional bone graft. None of the patients in group B diagnosed with delayed union or nonunion (P fracture promoted callus formation and union rate compared with MIPO without appositional screw fixation. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Internal fixation of mandibular angle fractures: a meta-analysis.

Science.gov (United States)

Regev, Eran; Shiff, Jacob S; Kiss, Alex; Fialkov, Jeffrey A

2010-06-01

The degree of rigidity of internal fixation required for the treatment of mandibular angle fractures has long been at the center of debate in the literature. A statistical comparison between rigid fixation and monocortical fixation has been difficult because of multiple terms, definitions, and technical variations. The purpose of this study was to use the meta-analysis tool to combine information from multiple studies and to compare complication rates for different fixation methods. An English language literature search was conducted for articles on mandibular angle fractures. Information was collected on four variables of interest: compression/noncompression technique, monocortical/bicortical screws, number of plates, and location of plates. Five outcome rates were analyzed: infection, reoperation, hardware removal, malunion, and nonunion. Meta-analyses were run using Comprehensive Meta Analysis, version 2.2.03. Twenty-four studies with relevant data on the variables and outcomes of interest met the inclusion criteria. Significantly higher rates of infection, reoperation, and hardware removal were found for compression compared with noncompression, two plates compared with one plate, and for plates located on both the inferior and superior borders as compared with superior or inferior only. There were also significantly higher infection rates for bicortical screws compared with monocortical screws and higher malunion rates for compression compared with noncompression plating techniques. The results of this meta-analysis found lower complication rates with the use of noncompression, monocortical, and single-plate fixation, supporting the trend toward a single, superiorly placed, monocortical miniplate for fixation of mandibular angle fractures.

Anatomical evidence for the anterior plate fixation of sacroiliac joint.

Science.gov (United States)

Bai, Zhibiao; Gao, Shichang; Liu, Jia; Liang, Anlin; Yu, Weihua

2018-01-01

The iatrogenic injuries to the lumbar nerves during the fixation the sacroiliac (SI) joint fractures with anterior plates were often reported. No specific method had been reported to avoid it. This study was done to find a safer way of placing the anterior plates and screws for treating the sacroiliac (SI) joint fracture and/or dislocation. The research was performed using 8 male and 7 female normal corpse pelvic specimens preserved by 10% formalin solution. Try by measuring the horizontal distance from L4, L5 nerve roots to the sacroiliac joint and perpendicular distance from L4, L5 nerve roots to the ala sacralis, the length of L4, L5 nerve roots from intervertebral foramen to the edge of true pelvis, the diameter of L4, L5 nerve roots. The angles between the sacroiliac joint and sagittal plane were measured on the CT images. The horizontal distance between the lateral side of the anterior branches of L4, L5 nerve roots and the sacroiliac joint decreased gradually from the top to the bottom. The widest distances for L4,5 were 2.1 cm (range, 1.74-2.40) and 2.7 cm (range, 2.34-3.02 cm), respectively. The smallest distances for L4, 5 were 1.2 cm (range, 0.82-1.48 cm) and 1.5 cm (range, 1.08-1.74 cm), respectively. On CT images, the angle between the sacroiliac joint and sagittal plane was about 30°. If we use two anterior plates to fix the sacroiliac joint, It is recommended to place one plate on the superior one third part of the joint, with exposing medially no more than 2.5 cm and the other in the middle one third part of the joint, with elevating periosteum medially no more than 1.5 cm. The screws in the sacrum are advised to incline medially about 30° directing to the true pelvis. Copyright © 2017. Published by Elsevier B.V.

Comparative evaluation of 2.3 mm locking plate system vs conventional 2.0 mm non locking plate system for mandibular condyle fracture fixation: a seven year retrospective study.

Science.gov (United States)

Zhang, J; Wang, X; Wu, R-H; Zhuang, Q-W; Gu, Q P; Meng, J

2015-01-01

This retrospective study evaluated the efficacy of a 2.3 mm locking plate/screw system compared with a 2.0-mm non-locking plate/screw system in fixation of isolated non comminuted mandibular condyle fractures. Surgical records of 101 patients who received either a 2.3 mm locking plate (group A, n = 51) or 2.0 mm non locking plate (group B, n = 50) were analyzed. All patients were followed up to a minimum of 6 months postoperatively and evaluated for hardware related complications, occlusal stability, need for and duration of MMF and mandibular functional results. Four complications occurred in the locking group and eighteen in the non locking group with complication rates equalling 8% and 36% respectively. When comparing the overall results according to plates used, the χ2 test showed a statistically significant difference between the locking and non locking plates (p Mandibular condyle fractures treated with a 2.3 mm locking plate exhibited stable osteosynthesis, were associated with minimal complications and resulted in acceptable mandibular range of motion compared with a 2.0 mm non locking plate.

Computer-assisted preoperative simulation for positioning and fixation of plate in 2-stage procedure combining maxillary advancement by distraction technique and mandibular setback surgery.

Science.gov (United States)

Suenaga, Hideyuki; Taniguchi, Asako; Yonenaga, Kazumichi; Hoshi, Kazuto; Takato, Tsuyoshi

2016-01-01

Computer-assisted preoperative simulation surgery is employed to plan and interact with the 3D images during the orthognathic procedure. It is useful for positioning and fixation of maxilla by a plate. We report a case of maxillary retrusion by a bilateral cleft lip and palate, in which a 2-stage orthognathic procedure (maxillary advancement by distraction technique and mandibular setback surgery) was performed following a computer-assisted preoperative simulation planning to achieve the positioning and fixation of the plate. A high accuracy was achieved in the present case. A 21-year-old male patient presented to our department with a complaint of maxillary retrusion following bilateral cleft lip and palate. Computer-assisted preoperative simulation with 2-stage orthognathic procedure using distraction technique and mandibular setback surgery was planned. The preoperative planning of the procedure resulted in good aesthetic outcomes. The error of the maxillary position was less than 1mm. The implementation of the computer-assisted preoperative simulation for the positioning and fixation of plate in 2-stage orthognathic procedure using distraction technique and mandibular setback surgery yielded good results. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Flexible fixation and fracture healing

DEFF Research Database (Denmark)

Schmal, Hagen; Strohm, Peter C; Jaeger, Martin

2011-01-01

, noncomminuted fractures. External fixation uses external bars for stabilization, whereas internal fixation is realized by subcutaneous placement of locking plates. Both of these "biologic" osteosynthesis methods allow a minimally invasive approach and do not compromise fracture hematoma and periosteal blood...

Minimally invasive plate osteosynthesis for humeral shaft fracture: a reproducible technique with the assistance of an external fixator.

Science.gov (United States)

Lee, Hyun-Joo; Oh, Chang-Wug; Oh, Jong-Keon; Apivatthakakul, Theerachai; Kim, Joon-Woo; Yoon, Jong-Pil; Lee, Dong-Joo; Jung, Jae-Wook

2013-05-01

Minimally invasive plate osteosynthesis (MIPO) has become a popular option for treatment of humeral shaft fractures. However, indirect reduction might risk unpromising results, with mal-alignment/mal-union or nonunion. The purpose of this study was to describe a reproducible MIPO technique that used an external fixator during the procedure as a tool for reduction and maintenance, and to assess the outcomes in patients with humeral shaft fracture. Of 31 consecutive cases of humeral shaft fracture in 30 patients, 29 were included in this study. There were seven simple (type A) and 22 comminuted (type B or C) fractures. After the insertion of one Schanz pin on each proximal and distal humerus, a provisional reduction was achieved by connecting the pins with a monolateral external fixator. The MIPO procedure was then performed over the anterior aspect of the humerus. To evaluate the efficacy of the provisional reduction by external fixator, coronal and sagittal alignments were assessed. We also assessed bony and functional results, including complications, from this technique. There was no case of mal-union >10°, and mean angulation was 1.3° (range 0°-9°) in the coronal plane and 1.2° (range 0°-8°) in the sagittal plane. Twenty-eight of 29 fractures were united, including three delayed unions, with a mean union time of 19.1 weeks (range 12.3-38.4 weeks) and a mean follow-up of 20.8 months (range 13.5-31.0 months). There was one hypertrophic nonunion that healed after fixing with two additional screws. Except one patient with associated injury in the elbow, all patients recovered to pre-injury joint motion. There were two cases of postoperative radial nerve palsy that both recovered completely. We attributed them to manipulation, and not to the Schanz pins or plate fixation. Surgical treatment of humeral shaft fractures with external fixator-assisted reduction and MIPO resulted in excellent reductions and high union rates.

Features of Three- and Four-Part Proximal Humeral Fractures and Outcome of Internal Fixation Using the Philos® Locking Plate

Directory of Open Access Journals (Sweden)

Ali Sadighi

2017-03-01

Full Text Available Background: Proximal humeral fractures are among common types of fractures and remain a challenging issue for surgical management. This study aimed to assess the clinical outcomes and complication rates of three- vs. four-part proximal humeral fractures, treated with internal fixation using the Philos® plate. Material and Methods: In this cohort study, a total of 30 consecutive patients with three-part or four-part proximal humeral fractures based on the Neer classification were included. Surgical treatment was performed with open reduction and internal fixation using the Philos® plate. The constant score was evaluated 6 months later in follow-up. The P<0.05 was considered significant. Results: Four-part fractures were mainly caused by trauma from above, while insults of opposite direction were responsible for more than half of 3 part fractures (P=0.01. Open fractures were only observed in patients with a four-part fracture (P=0.018. No significant differences were noticed regarding gender, cause, and side of the fracture. The presence of other fractures, fracture of the implant, reduction loss, avascular necrosis (AVN of humerus head, rotator cuff injury, and revision surgery were significantly higher in patients with four-part fractures. The mean constant score was 81.40±11.61 and 65.09±16.09 for three-part and four-part fractures, respectively (P=0.006. Conclusion: Open reduction and internal fixation with Philos® plate yield acceptable results in both types of fractures, however, the prognosis of this intervention is poorer four-part fractures.

[Case-control study on effects of external fixation combined with limited internal fixation for the treatment of Pilon fractures of Rüedi-Allgower type III].

Science.gov (United States)

Duan, Da-Peng; You, Wu-Lin; Ji, Le; Zhang, Yong-Tao; Dang, Xiao-Qian; Wang, Kun-Zheng

2014-01-01

To analyze the effects of three surgical operations in the treatment of Pilon fracture of Rüedi-Allgower type III, and put forward the best therapeutic method. The clinical data of 33 patients with Pilon fracture who received surgical operations (plaster immobilization group, 10 cases; distal tibia anatomical plate group, 11 cases; external fixation with limited internal fixation group, 12 cases) from October 2009 to January 2012 were analyzed. There were 5 males and 5 females, ranging in age from 24 to 61 years in the plaster immobilization group. There were 7 males and 4 females, ranging in age from 21 to 64 years in the distal tibia anatomical plate group. There were 7 males and 5 females, ranging in age from 23 to 67 years in the external fixation with limited internal fixation group. The Ankle X-ray of Pilon fracture after operation, ankle score, early and late complications were collected. Bourne system was used to evaluate ankle joint function. After 8 months to 3 years follow-up, it was found that three kinds of treatment had significant differences in the outcomes and complications (P external fixation with limited internal fixation group got the best results. The number of anatomic reduction cases in the external fixation with limited internal fixation group (7 cases) and the distal tibia anatomical plate group (8 cases) was more than the plaster immobilization group (2 cases). According to the ankle score, 8 patients got an excellent result, 3 good and 1 poor in the limited internal fixation group ,which was better than those of distal tibia anatomical plate group (5 excellent, 4 good and 2 poor) and the plaster immobilization group (3 excellent, 4 good and 3 poor). The number of early and late complications in the external fixation with limited internal fixation group was more than those in the plaster immobilization group and the distal tibia anatomical plate group (Pexternal fixation with limited internal fixation in the treatment of Pilon fracture

Tricortical cervical inter-body screw fixation.

Directory of Open Access Journals (Sweden)

Goel A

1997-01-01

Full Text Available A new tricortical method of screw implantation for anterior cervical interbody plate fixation is described. The screws are placed obliquely such that they engage the anterior cortex of the body and traverse through the cortices adjoining the disc space. By this method the screws not only hold the plate firmly with a tricortical purchase, but by virtue of their course stabilize the two adjoining vertebral bodies by themselves. Sixteen patients were treated by this method. In three of these cases only tricortical screws without the metal plate were used for fixation. The advantages of the technique are discussed.

Biomechanical evaluation of the impact of various facet joint lesions on the primary stability of anterior plate fixation in cervical dislocation injuries: a cadaver study: Laboratory investigation.

Science.gov (United States)

Oberkircher, Ludwig; Born, Sebastian; Struewer, Johannes; Bliemel, Christopher; Buecking, Benjamin; Wack, Christina; Bergmann, Martin; Ruchholtz, Steffen; Krüger, Antonio

2014-10-01

Injuries of the subaxial cervical spine including facet joints and posterior ligaments are common. Potential surgical treatments consist of anterior, posterior, or anterior-posterior fixation. Because each approach has its advantages and disadvantages, the best treatment is debated. This biomechanical cadaver study compared the effect of different facet joint injuries on primary stability following anterior plate fixation. Fractures and plate fixation were performed on 15 fresh-frozen intact cervical spines (C3-T1). To simulate a translation-rotation injury in all groups, complete ligament rupture and facet dislocation were simulated by dissecting the entire posterior and anterior ligament complex between C-4 and C-5. In the first group, the facet joints were left intact. In the second group, one facet joint between C-4 and C-5 was removed and the other side was left intact. In the third group, both facet joints between C-4 and C-5 were removed. The authors next performed single-level anterior discectomy and interbody grafting using bone material from the respective thoracic vertebral bodies. An anterior cervical locking plate was used for fixation. Continuous loading was performed using a servohydraulic test bench at 2 N/sec. The mean load failure was measured when the implant failed. In the group in which both facet joints were intact, the mean load failure was 174.6 ± 46.93 N. The mean load failure in the second group where only one facet joint was removed was 127.8 ± 22.83 N. In the group in which both facet joints were removed, the mean load failure was 73.42 ± 32.51 N. There was a significant difference between the first group (both facet joints intact) and the third group (both facet joints removed) (p cadaver study, primary stability of anterior plate fixation for dislocation injuries of the subaxial cervical spine was dependent on the presence of the facet joints. If the bone in one or both facet joints is damaged in the clinical setting, anterior plate

Proximal humeral fractures: the role of calcium sulphate augmentation and extended deltoid splitting approach in internal fixation using locking plates.

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Somasundaram, K; Huber, C P; Babu, V; Zadeh, H

2013-04-01

The aim of our study is to analyse the results of our surgical technique for the treatment of proximal humeral fractures and fracture dislocations using locking plates in conjunction with calcium sulphate bone-substitute augmentation and tuberosity repair using high-strength sutures. We used the extended deltoid-splitting approach for fracture patterns involving displacement of both lesser and greater tuberosities and for fracture-dislocations. Optimal surgical management of proximal humeral fractures remains controversial. Locking plates have become a popular method of fixation. However, failure of fixation may occur if they are used as the sole method of fixation in comminuted fractures, especially in osteopenic bone. We retrospectively analysed 22 proximal humeral fractures in 21 patients; 10 were male and 11 female with an average age of 64.6 years (range 37-77). Average follow-up was 24 months. Eleven of these fractures were exposed by the extended deltoid-splitting approach. Fractures were classified according to Neer and Hertel systems. Preoperative radiographs and computed tomography (CT) scans in three- and four-part fractures were done to assess the displacement and medial calcar length for predicting the humeral head vascularity. According to the Neer classification, there were five two-part, six three-part, five four-part fractures and six fracture-dislocations (two anterior and four posterior). Results were assessed clinically with disabilities of the arm, shoulder and hand (DASH) scores, modified Constant and Murley scores and serial postoperative radiographs. The mean DASH score was 16.18 and the modified Constant and Murley score was 64.04 at the last follow-up. Eighteen out of twenty-two cases achieved good clinical outcome. All the fractures united with no evidence of infection, failure of fixation, malunion, tuberosity failure, avascular necrosis or adverse reaction to calcium sulphate bone substitute. There was no evidence of axillary nerve

Anterior cervical fusion: the role of anterior plating.

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Daffner, Scott D; Wang, Jeffrey C

2009-01-01

Treatment of cervical pathology requires a clear understanding of the biomechanical benefits and limitations of cervical plates, their indications, and their associated complications. The use of anterior cervical plates has evolved significantly since their early application in cervical trauma. They have become widely used for anterior cervical decompression and fusion for cervical spondylosis. Plate design has undergone significant refinement and innovation, from the initial unlocked plates requiring bicortical purchase to the latest rotationally and translationally semiconstrained dynamic plates. Excellent clinical results have been reported for single-level anterior cervical decompression and fusion with or without plate fixation; however, the addition of an anterior cervical plate clearly leads to earlier fusion and better clinical results in longer fusions. Longer fusions should ideally consist of corpectomies and strut grafting because the decreased number of fusion surfaces tends to lead to higher fusion rates. Although anterior plate fixation leads to higher fusion rates in fusions of three or more levels, the associated pseudarthrosis rate is still high. The use of dynamic plates, through increased load sharing across the graft and decreased stress shielding, may improve fusion rates, particularly in long fusions. Nevertheless, adjuvant posterior fixation is recommended for fusions of more than three vertebral levels. Anterior plate fixation may be of particular benefit in the management of traumatic injuries, in revision settings, and in the treatment of smokers. Complications unique to plate fixation include hardware breakage and migration as well as ossification of the adjacent disk levels.

Fracture of an uncemented tantalum patellar component

Directory of Open Access Journals (Sweden)

Nathan L. Grimm, MD

2016-06-01

Full Text Available A 62-year-old man presented with the acute, atraumatic onset of pain 3 years after uncemented right total knee arthroplasty. He complained of new mechanical locking with the knee held in extension on examination and unable to flex the knee. On the plain radiographs, the patellar component peg was fractured and the plate was dislocated. The knee was immobilized, and revision to a cemented 3-peg component was performed. Fracture of a single-peg, tantalum-backed uncemented patellar component has not been described. Clinical suspicion for this should be given in the setting of acute locking. We recommend revision with a cemented polyethylene component.

Use of a percutaneous osteotomy with plate fixation in hallux valgus correction.

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Díaz Fernández, Rodrigo

2017-09-20

With hundreds of operative methods described for correction of hallux valgus we can state that the ideal surgical treatment is still controversial. The Bösch technique has been used as a percutaneous way of correcting hallux valgus deformities with the use of a pin fixation. The aim of this study is to evaluate a new method of fixation by using a percutaneous locking plate. Between June 2013 and January 2015, 24 consecutive percutaneous subcapital osteotomies of the first metatarsal bone were performed for the treatment of painful hallux valgus deformities in 24 patients. Additional surgical procedures included DMMO's (Distal Metatarsal Minimally-Invasive Osteotomies) in 12 of the operated feet (44.44%); minor digits were corrected in 7 cases (25.9%). An Akin procedure was performed in 81% of cases and all cases underwent an adductor hallucis tenotomy. All patients were clinically assessed using the AOFAS score. Radiographic measures included the preoperative and postoperative values of the Hallux Valgus Angle (HVA), Intermetatarsal Angle (IMA), and the Distal Metatarsal Articular Angle (DMAA). The mean correction achieved improved for AHV from 36.57±7.1 to 12.22±8.69°, for IMA from 13.8±1.59 to 7.08±2.72 and for DMAA from 13.98±7.38 to 6.07±4.99. Clinically, scores on the AOFAS scale improved from a 45.8±9.6 to 91.29±9.8. Although healing of the osteotomies was observed radiographically within 6 to 12 weeks, two cases (8.3%) exhibited delayed healing. There were no cases of nonunion. There were no superficial or deep infections or wound healing problems. Plate had to be removed in 3 cases (12.5%). This technique modification is an acceptable procedure to correct hallux valgus in patients with a moderate level of deformity. Level IV. Copyright © 2017 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

Early Experience with Biodegradable Fixation of Pediatric Mandibular Fractures

OpenAIRE

Mazeed, Ahmed Salah; Shoeib, Mohammed Abdel-Raheem; Saied, Samia Mohammed Ahmed; Elsherbiny, Ahmed

2014-01-01

This clinical study aims to evaluate the stability and efficiency of biodegradable self-reinforced poly-l/dl-lactide (SR-PLDLA) plates and screws for fixation of pediatric mandibular fractures. The study included 12 patients (3–12 years old) with 14 mandibular fractures. They were treated by open reduction and internal fixation by SR-PLDLA plates and screws. Maxillomandibular fixation was maintained for 1 week postoperatively. Clinical follow-up was performed at 1 week, 6 weeks, 3 months, and...

Computer-assisted preoperative simulation for positioning and fixation of plate in 2-stage procedure combining maxillary advancement by distraction technique and mandibular setback surgery

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Hideyuki Suenaga

2016-01-01

Conclusion: The implementation of the computer-assisted preoperative simulation for the positioning and fixation of plate in 2-stage orthognathic procedure using distraction technique and mandibular setback surgery yielded good results.

Analysis and an overview of fixators in medicine and the methods of processing materials for producing fixators

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Dalibor Milojko Đenadić

2013-06-01

Full Text Available The fixator is a medical device that provides support to fractured biological structures. Metal biomaterials are mainly used for replacing broken or damaged hard tissues such as bones because of their high strenght, toughness and corrosion resistance. Materials such as stainless steel, titanium and aluminium alloys (Ti-6Al-4V, cobalt and chromium alloys, composite materials and other biocompatible materials are used in orthopedy for the stabilization of connective tissue injuries or as a substitute for the bone tissues. Fixators are classified according to the place of installation to external and internal fixators. Widely used medical fixators are pins, rods plates, screws, pipes, wires, nails and external fixators. Conventional and non-conventional methods of processing are used in the production process for all types of fixators. Introduction Fixators are medical devices manufactured to support damaged biological structures. In the field of orthopedic surgery that deals with skeletal disorders such as bone, spine, joints, muscles and tendons injuries and diseases, various metals, titanium and cobalt alloys etc. are used to stabilize the supporting tissue injuries or as a substitute for bone tissues. Metallic implants are frequently used in orthopedic surgery as joint prosthesis (hip, knee and elbow fracture fixation devices (plates, screws, external fixators and devices for the fixation of the spine. In principle, fixators are devided into external and internal ones, depending on the place of installation (outside or inside the body. The most common types of medical fixators are pins, rods and plates. This paper presents some of the most common materials used for the production of fixators, their processing and possibilties of use in medicine for various purposes. Types of fixators and materials used for their production Nowadays, biocompatible materials are usually used for the production of fixators and implants. These materials show good

[Double-plate fixation via combined approaches for the treatment of old tibial plateau fractures of Schatzker type IV].

Science.gov (United States)

Tan, Hong-Lue; Dai, Peng-Yi; Liu, Wei-Feng; Yuan, Yan-Hao

2017-10-25

To explore the clinical efficacy of double-plate fixation for the treatment of old tibial plateau fractures with Schatzker type IV through anterior midline and posteromedial approaches. From July 2013 to July 2015, 15 patients with old tibial plateau fractures were treated with internal fixation using locking reconstructive plate for the posteromedial fragment and anatomical locking plate for anteromedial fragment through antero midline and posteromedial approaches. There were 9 males and 6 females, with an average age of 49.2 years old (ranged, 21 to 61 years old). Eight patients had injured in the left side and 7 in the right side. According to Schatzker classification, all patients were type IV. The mean interval from injury to operation was 26.5 days (ranged, 21 to 65 days). The main clinical symptoms before operation were knee joint swelling, pain, deformity and limitation of motion. The X-ray and CT confirmed the fracture type. The indexes such as tibial plateau tibial shaft angle (TPA), femoral tibial angle (FTA) and posterior slope angle (PSA) were compared between immediate postoperation and final follow-up using postoperative X-ray film. The knee functions were evaluated using the HSS (Hospital for Special Surgery) knee score system. Two patients had incision complications which healed by correct treatment, 1 patient had traumatic arthritis. All patients were followed up for mean 16.6 months (ranged, 13 to 24 months). No infections, deep venous thrombosis, implant loosening and breakage, fragment displacement, plateau surface collapse and bone nonunion found. The bone union time ranged from 3 to 8 months (mean 6.07 months) after operation. The average immediate postoperative value of TPA, FTA and PSA were(86.81±1.67)°, (168.00±3.29)° and(10.20±1.47)° respectively; and(86.47±1.67)°, (168.53±3.03)° and (10.54±1.21)° respectively at the final follow-up evaluation, showing no statistical differences( P >0.05). According to the HSS score system, 26

Electrorecovery of tantalum in molten fluorides

International Nuclear Information System (INIS)

Espinola, A.; Dutra, A.J.B.; Silva, F.T. da

1988-01-01

Considering the privileged situation of Brazil as a productor of tantaliferous minerals, the authors have in view the development of a technology for production of metallic tantalum via molten salts electrolysis; this has the advantage of improving the aggregate value of exportation products, additionally to tantalum oxide and tantalum concentrates. Having in view the preliminary determintion of better conditions of temperature, electrolyte composition and current density for this process, electrolysis were conducted with a solvent composed of an eutetic mixture of lithium, sodium and potassium fluoride for dipotassium fluotantalate and occasionally for tantalum oxide. Current efficiencies as high as 83% were obtained in favoured conditions. (author) [pt

Dual-energy X-ray absorptiometry and force-plate analysis of gait in dogs with healed femora after leg-lengthening plate fixation

International Nuclear Information System (INIS)

Muir, P.; Markel, M.D.; Bogdanske, J.J.; Johnson, K.A.

1995-01-01

Dual-energy x-ray absorptiometry was used to measure bone mineral density of four regions in healed femora of nine dogs after fracture fixation with a leg-lengthening plate. Six to 85 months (mean, 46 months) after surgery, the bone mineral density of healed femora was not significantly different from the contralateral uninjured femora (P > .05; power = 0.8 at delta = 15%). Radiolucencies around the proximal screws, apparently associated with screw loosening, were seen on radiographic views of the healed femora of three dogs. In one of these dogs, one screw in the proximal metaphysis had broken. Force-plate analysis of gait was also performed on dogs at the time of bone mineral density measurement. Peak vertical force was decreased in the pelvic limb with the healed fracture compared with the contralateral unoperated limb (P < 0.05). Clinically apparent lameness in three dogs did not appear to be associated with altered bone mineral density and may have been caused by hip osteoarthritis, a nondisplaced hairline diaphyseal fracture, and screw loosening in conjunction with extensive post-traumatic soft tissue injury

Tantalum-based semiconductors for solar water splitting.

Science.gov (United States)

Zhang, Peng; Zhang, Jijie; Gong, Jinlong

2014-07-07

Solar energy utilization is one of the most promising solutions for the energy crises. Among all the possible means to make use of solar energy, solar water splitting is remarkable since it can accomplish the conversion of solar energy into chemical energy. The produced hydrogen is clean and sustainable which could be used in various areas. For the past decades, numerous efforts have been put into this research area with many important achievements. Improving the overall efficiency and stability of semiconductor photocatalysts are the research focuses for the solar water splitting. Tantalum-based semiconductors, including tantalum oxide, tantalate and tantalum (oxy)nitride, are among the most important photocatalysts. Tantalum oxide has the band gap energy that is suitable for the overall solar water splitting. The more negative conduction band minimum of tantalum oxide provides photogenerated electrons with higher potential for the hydrogen generation reaction. Tantalates, with tunable compositions, show high activities owning to their layered perovskite structure. (Oxy)nitrides, especially TaON and Ta3N5, have small band gaps to respond to visible-light, whereas they can still realize overall solar water splitting with the proper positions of conduction band minimum and valence band maximum. This review describes recent progress regarding the improvement of photocatalytic activities of tantalum-based semiconductors. Basic concepts and principles of solar water splitting will be discussed in the introduction section, followed by the three main categories regarding to the different types of tantalum-based semiconductors. In each category, synthetic methodologies, influencing factors on the photocatalytic activities, strategies to enhance the efficiencies of photocatalysts and morphology control of tantalum-based materials will be discussed in detail. Future directions to further explore the research area of tantalum-based semiconductors for solar water splitting

Process for the production of a tantalum and niobium bearing concentrate from a tantalum and niobium bearing ferro-alloy

International Nuclear Information System (INIS)

Deweck, J.; Van, H.

1980-01-01

In a process for the production of a tantalum and niobium bearing concentrate from a tantalum and niobium bearing ferro-alloy containing tantalum and niobium as carbide, by treating the ferro-alloy in molten state with a controlled amount of an oxidizing agent in order to slag at least most of the tantalum and at least part of the niobium and by separting the so obtained slag phase from the metal phase, the improvement which comprises using air, oxygen enriched air or oxygen as oxidizing agent and adjusting the iron content to the ferro-alloy by adding at least 70% by weight of iron prior to the step of forming the slag so that at least most of the tantalum carbide is dissolved in the molten ferro-alloy

Tantalum: A strategic metal; Tantalo: Un metal estrategico

Energy Technology Data Exchange (ETDEWEB)

Lopez-Lopez, G.; Lopez-Lopez, J.; Garcia-Yagues, M. R.

2009-07-01

In nature, the main source of tantalum is an isomorphous series of minerals containing oxides of tantalum, niobium, iron and manganese, which are collectively known as columbine-tantalite (coltan). Upgraded Ta{sub 2}O{sub 5}-containing tin slags are also used as a secondary source of tantalum. Coltan, either naturally occurring or synthetically produced as concentrates from tin slags, are digested with hydrofluoric and sulphuric acid at an elevated temperature. the aqueous solution of ta-Nb in hydrofluoric acid is extracted in several continuously operating mixer-settler systems or extraction columns with an organic solvent like methyl isobutyl ketone. The organic phase is then scrubbed with 6-15 N H{sub 2}SO{sub 4} to separate the niobium from the tantalum by selective stripping. The tantalum salt is extracted from the organic phase with water or diluted aqueous ammonium fluoride solution, the demands of the solid tantalum capacitor industry for high quality, high surface area tantalum powders have driven improvements in the sodium reduction of K{sub 2}TaF{sub 7}. The much-improved chemistry reflects the many modifications to the process put in place after 1990 and the subsequent improvements in the electrical quality as measured by the performance of tantalum capacitors. (Author) 5 refs.

Mineral-deposit model for lithium-cesium-tantalum pegmatites

Science.gov (United States)

Bradley, Dwight C.; McCauley, Andrew D.; Stillings, Lisa L.

2017-06-20

derived by fractional crystallization. In cases where a parental granite pluton is not exposed, one is inferred to lie at depth. Lithium-cesium-tantalum LCT pegmatite melts are enriched in fluxing components including H2O, F, P, and B, which depress the solidus temperature, lower the density, and increase rates of ionic diffusion. This, in turn, enables pegmatites to form thin dikes and massive crystals despite having a felsic composition and temperatures that are significantly lower than ordinary granitic melts. Lithium-cesium-tantalum pegmatites crystallized at remarkably low temperatures (about 350–550 °C) in a remarkably short time (days to years).Lithium-cesium-tantalum pegmatites form in orogenic hinterlands as products of plate convergence. Most formed during collisional orogeny (for example, Kings Mountain district, North Carolina). Specific causes of LCT pegmatite-related magmatism could include: ordinary arc processes; over thickening of continental crust during collision or subduction; slab breakoff during or after collision; slab delamination before, during, or after collision; and late collisional extensional collapse and consequent decompression melting. Lithium-cesium-tantalum pegmatite deposits are present in all continents including Antarctica and in rocks spanning 3 billion years of Earth history. The global age distribution of LCT pegmatites is similar to those of common pegmatites, orogenic granites, and detrital zircons. Peak times of LCT pegmatite genesis at about 2640, 1800, 960, 485, and 310 Ma (million years before present) correspond to times of collisional orogeny and supercontinent assembly. Between these pulses were long intervals when few or no LCT pegmatites formed. These minima overlap with supercontinent tenures at ca. 2450–2225, 1625–1000, 875–725, and 250–200 Ma.Exploration and assessment for LCT pegmatites are guided by a number of observations. In frontier areas where exploration has been minimal at best, the key first

Treatment of Displaced Sacroiliac Fracture Using the Lateral Window for Short Plate Buttress Reduction and Percutaneous Sacroiliac Screw Fixation.

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Colin Murphy

2016-04-01

Full Text Available Fractures through the sacroiliac joint are very challenging to treat, technically difficult to reduce through closed methods on account of the multiaxial displacement of fractures fragments, frequently occur in very unwell patients, and have poor outcomes if malreduction is present. We describe a technique utilising the lateral window and a short buttress plate to reduce and stabilize the fragments prior to percutaneous fixation with sacroiliac screws.

Formation of nickel-tantalum compounds in tantalum fluoride halide melts

International Nuclear Information System (INIS)

Matychenko, Eh.S.; Zalkind, O.A.; Kuznetsov, B.Ya.; Orlov, V.M.; Sukhorzhevskaya, S.L.

2001-01-01

Interaction of nickel with NaCl-K 2 TaF 7 melt (14 mol.%) at 750 deg C was studied, the composition of intermetallic compounds formed in Ni-Ta system being analyzed, using the methods of chemical and X-ray phase analyses, IR spectroscopy. It was ascertained that composition of intermetallic compounds (Ni 3 Ta, Ni 2 Ta) depends on K 2 TaF 7 concentration in the melt, metallic tantalum additions, nickel substrate thickness and experiment duration. The mechanism of currentless deposition of tantalum on nickel was considered and the assumption was made that disproportionation reaction lies in the basis of the process [ru

Tantalum powder consolidation, modeling and properties

International Nuclear Information System (INIS)

Bingert, S.R.; Vargas, V.D.; Sheinberg, H.C.

1996-01-01

A systematic approach was taken to investigate the consolidation of tantalum powders. The effects of sinter time, temperature and ramp rate; hot isostatic pressing (HIP) temperature and time; and powder oxygen content on consolidation density, kinetics, microstructure, crystallographic texture, and mechanical properties have been evaluated. In general, higher temperatures and longer hold times resulted in higher density compacts with larger grain sizes for both sintering and HIP'ing. HIP'ed compacts were consistently higher in density than sintered products. The higher oxygen content powders resulted in finer grained, higher density HIP'ed products than the low oxygen powders. Texture analysis showed that the isostatically processed powder products demonstrated a near random texture. This resulted in isotropic properties in the final product. Mechanical testing results showed that the HIP'ed powder products had consistently higher flow stresses than conventionally produced plates, and the sintered compacts were comparable to the plate material. A micromechanics model (Ashby HIP model) has been employed to predict the mechanisms active in the consolidation processes of cold isostatic pressing (CIP), HIP and sintering. This model also predicts the density of the end product and whether grain growth should be expected under the applied processing conditions

Comparison of Internal Fixations for Distal Clavicular Fractures Based on Loading Tests and Finite Element Analyses

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Rina Sakai

2014-01-01

Full Text Available It is difficult to apply strong and stable internal fixation to a fracture of the distal end of the clavicle because it is unstable, the distal clavicle fragment is small, and the fractured region is near the acromioclavicular joint. In this study, to identify a superior internal fixation method for unstable distal clavicular fracture, we compared three types of internal fixation (tension band wiring, scorpion, and LCP clavicle hook plate. Firstly, loading tests were performed, in which fixations were evaluated using bending stiffness and torsional stiffness as indices, followed by finite element analysis to evaluate fixability using the stress and strain as indices. The bending and torsional stiffness were significantly higher in the artificial clavicles fixed with the two types of plate than in that fixed by tension band wiring (P<0.05. No marked stress concentration on the clavicle was noted in the scorpion because the arm plate did not interfere with the acromioclavicular joint, suggesting that favorable shoulder joint function can be achieved. The stability of fixation with the LCP clavicle hook plate and the scorpion was similar, and plate fixations were stronger than fixation by tension band wiring.

Miniplate fixation of Le Fort I osteotomies.

Science.gov (United States)

Rosen, H M

1986-12-01

The use of rigid, internal, three-dimensional fixation using vitallium bone plates in 28 consecutive Le Fort I osteotomies is presented. A minimum follow-up period of 6 months was required for inclusion in this patient group. Maxillary movements included advancements (17), intrusions (9), lengthenings (5), and retrusions (2). The majority of maxillae were moved in more than one plane of space. Technical details, complications, and relapse potential are discussed. Advantages of rigid plate fixation include marked reductions in the length of intermaxillary fixation with light training elastics only. Immediate postoperative airway problems are thereby eliminated. Six months of follow-up would appear to indicate a low potential for osseous relapse when compared to wire osteosynthesis, regardless of the direction of maxillary movement. The major disadvantage is the decreased ability of postoperative orthodontics to move dento-osseous segments if skeletal occlusal disharmony persists postoperatively. For this reason, close attention to preoperative planning and operative technique is critical for the success of this fixation method.

Dynamic compression plate (DCP) fixation of propagating medial condylar fractures of the third metacarpal/metatarsal bone in 30 racehorses: retrospective analysis (1990-2005).

Science.gov (United States)

Goodrich, L R; Nixon, A J; Conway, J D; Morley, P S; Bladon, B M; Hogan, P M

2014-11-01

An in-depth review of dynamic compression plate (DCP) fixation of propagating medial condyle fractures of the third metacarpus or metatarsus has not been previously reported. To describe the technique, evaluate short-term outcome and long-term race performance of racehorses that underwent DCP fixation for repair of propagating or spiralling medial condylar fractures of the third metacarpal (McIII) or metatarsal (MtIII) bone. Retrospective case series. The surgical case records of 30 horses with propagating fractures of the medial condyle of McIII or MtIII were reviewed. Medical information included: age, breed, sex, presentation, how injury occurred (racing or training), surgical treatment and post operative complications. Racing information included: starts, top 3 placing and career earnings. Long propagating fractures of the medial condyle of Mc/tIII were identified in 23 Thoroughbred (TB) and 7 Standardbred (STB) racehorses. The fracture spiralled proximally in 22 of 30 cases (73%). Standardbreds had a higher propensity for hindlimb involvement (71%), whereas TBs tended to have more front limb involvement (61%). Twelve of 30 (40%) horses raced post surgery. Career earnings were significantly lower for TB horses with medial condylar fractures; $34,916 when compared with the national average of $60,841 (P≤0.03). Overall, horses having DCP fixation for medial condylar fractures had less starts post surgery (3.1 TBs and 5.8 STBs) compared with the national average (7 TBs and 17.3 STBs) and decreased lifetime starts 13.4 (TBs) compared with 17.3 nationally. Propagating medial condyle fractures can be repaired with plate fixation to potentially lessen the risk of catastrophic fracture destabilisation and return to racing can be expected in 40% of horses. Further prospective studies are warranted comparing lag screw fixation with DCP fixation for repair of severe medial condylar fractures of the metacarpus/metatarsus. © 2013 The Authors. Equine Veterinary Journal

Locking plate versus external fixation for type C distal radius fractures: A meta-analysis of randomized controlled trials

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Dong Wang

2018-04-01

Full Text Available Purpose: Distal radial fracture is one of the most common fractures. Up to now, locking plates (LP and external fixation (EF are two conventional surgical approaches to type C radius fracture. Which method is superior has not yet reached a consensus. We try to assess the clinical effectiveness of the two interventions by this meta-analysis. Methods: We used network to search the PubMed, Embase, and Cochrane Medical Library of randomized controlled clinical trials about the type C distal radius fractures performed according to the search strategy mentioned in Cochrane Handbook 5.1.0 from Jan. 2005 to Jan. 2016. Patients in the experimental group were used LP, in the control group were included EF and other surgical approaches. Publication language was restricted to English. Studies that patient population and surgical indication did not define had been excluded. Studies must report at least one of the outcomes as follow: radial inclination, palmar tilt, ulnar variance, range of wrist flexion and extension, and range of wrist supination and pronation. The trials in which participants included children were excluded. We used Jadad study scores to appraise the study. Results: Seven studies included 162 patients (LP group and 190 patients (EF group. We compared the radial inclination, palmar tilt, ulnar variance, range of wrist flexion and extension, and range of wrist supination and pronation. The radial inclination were revealed a difference favoring LP over EF [WMD = 1.84, 95% CI (0.17, 3.50, p = 0.03] and the palmar tilt and ulnar variance was no significant difference between the two groups [(WMD = 3.61, 95% CI (0.00, 7.23, p = 0.05; WMD = 0.05, 95% CI (−0.99, 1.09, p = 0.93]. The functional activities of range of flexion and extension and range of supination and pronation between the two groups was no difference [WMD = 10.04, 95% CI (−6.88, 26.96, p = 0.24; WMD = 12.53, 95% CI (−9.99, 35.06, p = 0.28]. Conclusion

In vivo analysis of acromioclavicular joint motion after hook plate fixation using three-dimensional computed tomography.

Science.gov (United States)

Kim, Yoon Sang; Yoo, Yon-Sik; Jang, Seong Wook; Nair, Ayyappan Vijayachandran; Jin, Hyonki; Song, Hyun-Seok

2015-07-01

The clavicle hook plate can be used to treat acromioclavicular and coracoclavicular ligament injury or distal clavicular fracture with comminution. However, the hook plate can induce subacromial impingement, resulting in discomfort from the hardware. Our inclusion criteria were (1) men and women aged older than 20 years and (2) the presence of comminuted distal clavicular fractures (Neer type IIB) fixed with a hook plate (Synthes, Oberdorf, Switzerland). Three-dimensional computed tomography was obtained before removal of the hook plate. Seven patients were enrolled prospectively. The mean age was 42 years (range, 24-60 years). Zero degree images and abduction images were obtained. The sagittal cut surface was obtained 5 mm medial from the distal clavicle. The equator of the cut surface of the clavicle was compared with the full abduction model to analyze rotation. The center of the cut surface of the clavicle was compared with the full abduction model to analyze translation. The average difference in rotation of the distal clavicle between both shoulders was 16° (range, 3°-22°; P = .001). The mean difference in anterior translation of the distal clavicle was 2.2 mm (range, -0.7 to 5.6 mm; P = .030). Hook plate fixation at the acromioclavicular joint causes decreased internal rotation and increased anterior translation of the distal clavicle with respect to the medial acromion, indicating that the scapula relative to the thorax has decreased posterior tilting and increased external rotation in shoulders fixed using a hook plate. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Anterior fixation of the axis.

Science.gov (United States)

Traynelis, Vincent C; Fontes, Ricardo B V

2010-09-01

Although anterior fixation of the axis is not commonly performed, plate fixation of C2 is an important technique for treating select upper cervical traumatic injuries and is also useful in the surgical management of spondylosis. To report the technique and outcomes of C2 anterior plate fixation for a series of patients in which the majority presented with symptomatic degenerative spondylosis. Forty-six consecutive patients underwent single or multilevel fusions over a 7-year period; 30 of these had advanced degenerative disease manifested by myelopathy or deformity. Exposure was achieved with rostral extension of the standard anterior cervical exposure via careful soft tissue dissection, mobilization of the superior thyroid artery, and the use of a table-mounted retractor. It was not necessary to remove the submandibular gland, section the digastric muscle, or make additional skin incisions. Screws were placed an average of 4.6 mm (+/- 2.3 mm) from the inferior C2 endplate with a mean sagittal trajectory of 15.7 degrees (+/- 7.6 degrees). Short- and long-term procedure-related mortality was 4.4%, and perioperative morbidity was 8.9%. Patients remained intubated an average of 2.5 days following surgery. Dysphagia was initially reported by 15.2% of patients but resolved by the 8th postoperative week in all patients. Arthrodesis was achieved in all patients available for long-term follow-up. Multilevel fusions were not associated with longer hospitalization or morbidity. Anterior plate fixation of the axis for degenerative disease can be accomplished with acceptable morbidity employing an extension of the standard anterolateral route.

[Case-control study on minimally invasive percutaneous locking compression plate internal fixation for the treatment of type II and III pilon fractures].

Science.gov (United States)

Zhang, Zhi-Da; Ye, Xiu-Yi; Shang, Li-Yong; Xu, Rong-Ming; Zhu, Yan-Zhao

2011-12-01

To explore the clinical efficacy of delayed open reduction and internal fixation with minimally invasive percutaneous locking compression plate for the treatment of type II and III Pilon fractures. From January 2007 to September 2009, 32 patients with type II and III Pilon fractures were treated with open reduction and anatomic plate fixation (AP group) and minimally invasive percutaneous locking compression plate osteosynthesis (LCP group). There were 11 males and 6 females in AP group, with an average age of (37.4 +/- 13.3) years (ranged, 19 to 55 years). And there were 10 males and 5 females in LCP group, with an average age of (34.6 +/- 11.3) years(ranged, 21 to 56 years). The operating time, fracture healing time, aligned angulation and ankle function were compared between the two groups. All the patients were followed up, and the during ranged from 12 to 25 months, with a mean of (15.0 +/- 1.7) months. The average operation time was (76.5 +/- 8.3) min for AP group and (58.3 +/- 3.4) min for LCP group; the average time of fracture healing was (20.5 +/- 0.4) weeks for AP group and (15.7 +/- 0.2) weeks for LCP group; the total angulation between anterior posterior film and lateral film was averaged (6.6 +/- 0.5) degrees for AP group and (3.6 +/- 0.2) degrees for LCP group. As to above index, the results of LCP group were better than those of AP group (P ankle joint, the results of LCP group were better than those of AP group in ankle joint pain, wakling and ankle joint function (P fracture with less invasion, faster bone union, more stabilized fixation, quicker recovery of ankle function and fewer complications, which is more advantaged for type II and III Pilon fractures.

Hydride Olefin complexes of tantalum and niobium

NARCIS (Netherlands)

Klazinga, Aan Hendrik

1979-01-01

This thesis describes investigations on low-valent tantalum and niobium hydride and alkyl complexes, particularly the dicyclopentadienyl tantalum hydride olefin complexes Cp2Ta(H)L (L=olefin). ... Zie: Summary

Human bone ingrowth into a porous tantalum acetabular cup

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Gregory N. Haidemenopoulos

2017-11-01

Full Text Available Porous Tantalum is increasingly used as a structural scaffold in orthopaedic applications. Information on the mechanisms of human bone ingrowth into trabecular metal implants is rather limited. In this work we have studied, qualitatively, human bone ingrowth into a retrieved porous tantalum monoblock acetabular cup using optical microscopy, scanning electron microscopy and energy dispersive X-ray analysis. According to the results and taking into account the short operational life (4 years of the implant, bone ingrowth on the acetabular cup took place in the first two-rows of porous tantalum cells to an estimated depth of 1.5 to 2 mm. The bone material, grown inside the first raw of cells, had almost identical composition with the attached bone on the cup surface, as verified by the same Ca:P ratio. Bone ingrowth has been a gradual process starting with Ca deposition on the tantalum struts, followed by bone formation into the tantalum cells, with gradual densification of the bone tissue into hydroxyapatite. A critical step in this process has been the attachment of bone material to the tantalum struts following the topology of the porous tantalum scaffold. These results provide insight to the human bone ingrowth process into porous tantalum implants.

Cuttable plate fixation for small breed dogs with radius and ulna fractures: Retrospective study of 31 dogs.

Science.gov (United States)

Watrous, Gwyneth K; Moens, Noel M M

2017-04-01

This retrospective study evaluated complication rates for radius and ulna fractures in small breed dogs in which 1.5 mm to 2.7 mm cuttable bone plates were used for internal fixation. The medical records of all cases from 2004 to 2011 that were presented to our clinic were reviewed. Inclusion criteria were: dogs with body weight dogs met the inclusion criteria. Of 25 dogs that were available for follow-up, all achieved union, minor complications occurred in 9, and major complications occurred in 8. External coaptation was responsible for complications in 8 cases and the need for coaptation needs to be investigated. Excluding minor complications, 32% of patients required at least 1 additional surgery or additional hospitalization. All but 2 of the dogs returned to full function. The 1.5 mm straight plate was successfully used in all dogs with a body weight of 0.9 to 2.6 kg.

EXPERIMENTAL APPROVAL OF COMBINED FIXATION FOR FEMUR LENGTHENING

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M. A. Stepanov

2017-01-01

Full Text Available Elimination of congenital shortening of lower limb still remains a complex and unsolved orthopaedic task which requires an improved fixation technique as well as adjusted tactics of treatment and rehabilitation procedures.Purpose of the study — experimental approval of femur lengthening technique by external fixation with Ilizarov apparatus and internal fixation by plate.Materials and methods. Femur lengthening was performed in 6 mongrel dogs. Average animal age was 1,5±0,3 years, average weight — 20±5 kg, femur length — 22±2 sm. External apparatus with two supports and a titanium plate of an original design were applied under general anesthesia on the right femur of animals. Lengthening was performed manually at a rate of1 mm per day in 4 stages at a distance of 10% from initial segment length. External apparatus was removed on the last day of distraction after locking the plate. X-ray examination was done on the day of surgery, in 7, 14 and 25 days from the onset of distraction as well as in 14, 30, 60 and 90 days after completion of distraction and removal of external apparatus. Three animals were taken out of experiment in 30 days of fixation, remaining three animals — in 90 days. After euthanasia the authors performed autopsy of the organic femur complex and tissues contacting the plate.Results. The use of operated limb was not restricted during the whole distraction period. The authors observed first roentgenological signs of distraction osteogenesis on 7th day of lengthening. By the end of distraction period, at 25th day, shadows of regenerates demonstrated longitudinal striated structures in all cases. Median lucency area of 1–5 mm was located diagonally and across the regenerate or was intermittent. In 60 days of fixation X-rays demonstrated homogeneous regenerate. External fixation index was 13,9±1,5 days/sm (p≤0,05. The authors observed no cases of implants fracture or deformity during the experiment

Preparation of potassium-reduced tantalum powders

International Nuclear Information System (INIS)

Kolosov, V.N.; Miroshnichenko, M.N.; Orlov, V.M.; Prokhorova, T.Yu.

2005-01-01

Characteristics of tantalum powders prepared by reduction of molten potassium heptafluorotantalate with liquid potassium are studied in a temperature range of 750 - 850 deg C using potassium chloride as a flux at a ratio of K 2 TaF 7 : KCl = 1, 2, and 3. The use of potassium as a reducing agent facilitates washing of tantalum powders for impurity salt removal, reduces sodium content and leakage currents in the anodes. As compared to sodium process, the potassium reduction results in a high yield of sponge material, a decrease in the specific surface area and yield of tantalum powder suitable for manufacture of capacitor anodes [ru

Mechanical design optimization of bioabsorbable fixation devices for bone fractures.

Science.gov (United States)

Lovald, Scott T; Khraishi, Tariq; Wagner, Jon; Baack, Bret

2009-03-01

Bioabsorbable bone plates can eliminate the necessity for a permanent implant when used to fixate fractures of the human mandible. They are currently not in widespread use because of the low strength of the materials and the requisite large volume of the resulting bone plate. The aim of the current study was to discover a minimally invasive bioabsorbable bone plate design that can provide the same mechanical stability as a standard titanium bone plate. A finite element model of a mandible with a fracture in the body region is subjected to bite loads that are common to patients postsurgery. The model is used first to determine benchmark stress and strain values for a titanium plate. These values are then set as the limits within which the bioabsorbable bone plate must comply. The model is then modified to consider a bone plate made of the polymer poly-L/DL-lactide 70/30. An optimization routine is run to determine the smallest volume of bioabsorbable bone plate that can perform and a titanium bone plate when fixating fractures of this considered type. Two design parameters are varied for the bone plate design during the optimization analysis. The analysis determined that a strut style poly-L-lactide-co-DL-lactide plate of 690 mm2 can provide as much mechanical stability as a similar titanium design structure of 172 mm2. The model has determined a bioabsorbable bone plate design that is as strong as a titanium plate when fixating fractures of the load-bearing mandible. This is an intriguing outcome, considering that the polymer material has only 6% of the stiffness of titanium.

Computer-assisted preoperative simulation for positioning of plate fixation in Lefort I osteotomy: A case report

Directory of Open Access Journals (Sweden)

Hideyuki Suenaga

2016-06-01

Full Text Available Computed tomography images are used for three-dimensional planning in orthognathic surgery. This facilitates the actual surgery by simulating the surgical scenario. We performed a computer-assisted virtual orthognathic surgical procedure using optically scanned three-dimensional (3D data and real computed tomography data on a personal computer. It helped maxillary bone movement and positioning and the titanium plate temporary fixation and positioning. This simulated the surgical procedure, which made the procedure easy, and we could perform precise actual surgery and could forecast the postsurgery outcome. This simulation method promises great potential in orthognathic surgery to help surgeons plan and perform operative procedures more precisely.

Surgical plate fixation of multiple rib fractures: a case report.

Science.gov (United States)

Mitev, Konstantin; Neziri, Dashurie; Stoicovski, Emil; Mitrev, Zan

2018-05-29

The healthcare system in developing countries is limited; particularly, medical specialties such as emergency and trauma medicine are underdeveloped. Consequently, trauma injuries sustained in traffic accidents result in chronic morbidity more often than similar cases in developed countries. Multiple rib fractures induce significant patient morbidity. Current international guidelines recommend a multidisciplinary, surgery-based treatment approach to achieve optimal clinical benefit. We admitted a 41-year-old Albanian man to our emergency department following a pedestrian-vehicle accident 5 days earlier. He presented with severe upper thoracic pain, chest deformity, dyspnea, tachycardia, subcutaneous emphysema, and hematoma. Chest radiography pointed to hypoventilated lung fields and a minor pleural effusion. Computed tomographic scans indicated displaced fractures of right lateral ribs 5 -11, hyperdensity regions from bone fragments, and pulmonary contusion. The treatment consisted of surgical fixation of ribs 7-10 using titanium reconstruction plates and cortical locking screws. The patient's clinical condition rapidly improved postoperatively. Follow-up at 6 weeks confirmed a full return to preoperative daily activities and a high quality of life. In this case report, we present a novel and promising development in the field of trauma medicine in the Republic of Macedonia. Trauma injuries can be treated via advanced multidisciplinary medical care according to international standards, allowing optimal health recovery.

Early Experience with Biodegradable Fixation of Pediatric Mandibular Fractures.

Science.gov (United States)

Mazeed, Ahmed Salah; Shoeib, Mohammed Abdel-Raheem; Saied, Samia Mohammed Ahmed; Elsherbiny, Ahmed

2015-09-01

This clinical study aims to evaluate the stability and efficiency of biodegradable self-reinforced poly-l/dl-lactide (SR-PLDLA) plates and screws for fixation of pediatric mandibular fractures. The study included 12 patients (3-12 years old) with 14 mandibular fractures. They were treated by open reduction and internal fixation by SR-PLDLA plates and screws. Maxillomandibular fixation was maintained for 1 week postoperatively. Clinical follow-up was performed at 1 week, 6 weeks, 3 months, and 12 months postoperatively. Radiographs were done at 1 week, 3 months, and 12 months postoperatively to observe any displacement and fracture healing. All fractures healed both clinically and radiologically. No serious complications were reported in the patients. Normal occlusion was achieved in all cases. Biodegradable osteofixation of mandibular fractures offers a valuable clinical solution for pediatric patients getting the benefit of avoiding secondary surgery to remove plates, decreasing the hospital stay, further painful procedures, and psychological impact.

Dynamic plate osteosynthesis for fracture stabilization: how to do it

Directory of Open Access Journals (Sweden)

Juerg Sonderegger

2010-01-01

Full Text Available Plate osteosynthesis is one treatment option for the stabilization of long bones. It is widely accepted to achieve bone healing with a dynamic and biological fixation where the perfusion of the bone is left intact and micromotion at the fracture gap is allowed. The indications for a dynamic plate osteosynthesis include distal tibial and femoral fractures, some midshaft fractures, and adolescent tibial and femoral fractures with not fully closed growth plates. Although many lower limb shaft fractures are managed successfully with intramedullary nails, there are some important advantages of open-reduction-and-plate fixation: the risk of malalignment, anterior knee pain, or nonunion seems to be lower. The surgeon performing a plate osteosynthesis has the possibility to influence fixation strength and micromotion at the fracture gap. Long plates and oblique screws at the plate ends increase fixation strength. However, the number of screws does influence stiffness and stability. Lag screws and screws close to the fracture site reduce micromotion dramatically. Dynamic plate osteosynthesis can be achieved by applying some simple rules: long plates with only a few screws should be used. Oblique screws at the plate ends increase the pullout strength. Two or three holes at the fracture site should be omitted. Lag screws, especially through the plate, must be avoided whenever possible. Compression is not required. Locking plates are recommended only in fractures close to the joint. When respecting these basic concepts, dynamic plate osteosynthesis is a safe procedure with a high healing and a low complication rate. 

Resorbable versus titanium plates for orthognathic surgery.

Science.gov (United States)

Agnihotry, Anirudha; Fedorowicz, Zbys; Nasser, Mona; Gill, Karanjot S

2017-10-04

Recognition of some of the limitations of titanium plates and screws used for the fixation of bones has led to the development of plates manufactured from bioresorbable materials. Whilst resorbable plates appear to offer clinical advantages over metal plates in orthognathic surgery, concerns remain about the stability of fixation and the length of time required for their degradation and the possibility of foreign body reactions. This review compares the use of titanium versus bioresorbable plates in orthognathic surgery and is an update of the Cochrane Review first published in 2007. To compare the effects of bioresorbable fixation systems with titanium systems used during orthognathic surgery. Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 20 January 2017); the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 11) in the Cochrane Library (searched 20 January 2017); MEDLINE Ovid (1946 to 20 January 2017); and Embase Ovid (1980 to 20 January 2017). We searched the US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (clinicaltrials.gov; searched 20 January 2017), and the World Health Organization International Clinical Trials Registry Platform (searched 20 January 2017) for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. Randomised controlled trials comparing bioresorbable versus titanium fixation systems used for orthognathic surgery in adults. Two review authors independently screened the results of the electronic searches, extracted data and assessed the risk of bias of the included studies. We resolved disagreement by discussion. Clinical heterogeneity between the included trials precluded pooling of data, and only a descriptive summary is presented. This review included two trials, involving 103 participants, one comparing titanium with resorbable plates and screws and

Fabrication of a tantalum-clad tungsten target for KENS

International Nuclear Information System (INIS)

Kawai, Masayoshi; Kikuchi, Kenji; Kurishita, Hiroaki; Li, J.-F.; Furusaka, Michihiro

2001-01-01

Since the cold neutron source intensity of KENS (the spallation neutron source at High Energy Accelerator Research Organization) was decreased into about a third of the designed value because a cadmium liner at the cold neutron source deformed and obstructed the neutron beam line, the target-moderator-and-reflector assembly (TMRA) has been replaced by a new one aimed at improving the neutron performance and recovering the cold neutron source. The tantalum target has also been replaced by a tantalum-clad tungsten one. In order to bond the tantalum-clad with the tungsten block, a hot isostatic press (HIP) process was applied and optimized. It was found that gaseous interstitial impurity elements severely attacked tantalum and embrittled, and that the getter materials such as zirconium and tantalum were effective to reduce the embrittlement

[Application of the anatomic plate and trapezoid plate in comminuted intertrochanteric fracture combined with trochanteric coronal position fracture: a controlled clinical trial].

Science.gov (United States)

Zhen, Ping; Liu, Xing-Yan; Gao, Ming-Xuan; Tian, Qi

2010-05-01

To investigate the therapeutic effect and operative characteristic of the anatomic plate and trapezoid plate for treament of the comminuted intertrochanteric fracture combined with trochanteric coronal position fracture. From Jan. 1998 to Mar. 2007, 57 patients suffered from comminuted intertrochanteric fracture combined with trochanteric coronal position fracture were randomly divided into two groups, 21 patients in trapezoid plate group were treated with the trapezoid compression plate, included 11 males and 10 females with an average age of 41.8 years; and 36 patients in anatomic plate group were treated with the anatomic plate, included 17 males and 19 females with an average age of 42.1 years. All of the 57 fractures were A3 type according to AO classification. The functions of hip joints were evaluated according to the Harris hip functional standard score. All 57 patients were followed-up for 5 months to 9 years and 3 months with an average of 4.8 years. The healing time of the fractures was from 8 to 20 weeks with an average of 12.8 weeks. The results of Harris scoring showed the pain scores of the anatomic plate group were higher than that of the trapezoid plate group (P 0.05). In unstable comminuted intertrochanteric fracture combined with trochanteric coronal position fracture, the lateral wall of trochanteric is often destroyed. The anatomic plate and the trapeziod compression plate can provide effective internal fixation, while many othere internal fixation methods were limited in this kind of fracture. As compared with the anatomic plate fixation, the trapezoid compression plate fixation of comminuted intertrochanteric fracture combined with trochanteric coronal position fracture have several advantages, such as fewer complications, faster union of fracture and earlier recovery of joint functions.

Evaluation and reduction of magnetic resonance imaging artifacts induced by distinct plates for osseous fixation: an in vitro study @ 3T.

Science.gov (United States)

Rendenbach, Carsten; Schoellchen, Maximilian; Bueschel, Julie; Gauer, Tobias; Sedlacik, Jan; Kutzner, Daniel; Vallittu, Pekka K; Heiland, Max; Smeets, Ralf; Fiehler, Jens; Siemonsen, Susanne

2018-05-02

To analyze Magnetic Resonance Imaging (MRI) artifact induced at 3 Tesla by bioresorbable, titanium and glass fiber reinforced composite (GFRC) plates for osseous reconstruction. Fixation plates including bioresorbable polymers (Inion CPS, Inion Oy, Tampere, Finland; Rapidsorb, DePuy Synthes, Umkirch, Germany; Resorb X, Gebrueder KLS Martin GmbH, Tuttlingen, Germany), Glass fiber reinforced composite (Skulle Implants Oy, Turku, Finland) and titanium plates of varying thickness and design (DePuy Synthes, Umkirch, Germany) were embedded in agarose gel and a 3T MRI was performed using a standard protocol for head and neck imaging including T1w and T2w sequences. Additionally, different artifact reducing sequence techniques (slice encoding for metal artifact reduction (SEMAC) & ultrashort echotime (UTE)) were used and their impact on the extent of artifacts evaluated for each material. All titanium plates induced significantly more artefacts than resorbable plates in T1w and T2w sequences. Glass fiber-reinforced composites induced the least artefacts in both sequences. The total extent of artefacts increased with plate thickness and height. Plate thickness had no influence on the percentage of overestimation in all three dimensions. Titanium induced artefacts were significantly reduced by both artifact reducing sequence techniques. Polylactide, glass fiber-reinforced composite and magnesium plates produce less susceptibility artefacts in MRI compared to titanium, while the dimensions of titanium plates directly influence artifact extension. SEMAC and UTE significantly reduce metal artefacts at the expense of image resolution.

21 CFR 886.3100 - Ophthalmic tantalum clip.

Science.gov (United States)

2010-04-01

... blood vessels in the eye. (b) Classification. Class II (special controls). The device is exempt from the...) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3100 Ophthalmic tantalum clip. (a) Identification. An ophthalmic tantalum clip is a malleable metallic device intended to be implanted permanently...

Operative fixation of chest wall fractures: an underused procedure?

Science.gov (United States)

Richardson, J David; Franklin, Glen A; Heffley, Susan; Seligson, David

2007-06-01

Chest wall fractures, including injuries to the ribs and sternum, usually heal spontaneously without specific treatment. However, a small subset of patients have fractures that produce overlying bone fragments that may produce severe pain, respiratory compromise, and, if untreated mechanically, result in nonunion. We performed open reduction and internal fixation on seven patients with multiple rib fractures-five in the initial hospitalization and two delayed--as well as 35 sternal fractures (19 immediate fixation and 16 delayed). Operative fixation was accomplished using titanium plates and screws in both groups of patients. All patients with rib fractures did well; there were no major complications or infections, and no plates required removal. Clinical results were excellent. There was one death in the sternal fracture group in a patient who was ventilator-dependent preoperatively and extubated himself in the early postoperative period. Otherwise, the results were excellent, with no complications occurring in this group. Three patients had their plates removed after boney union was achieved. No evidence of infection or nonunion occurred. The excellent results achieved in the subset of patients with severe chest wall deformities treated initially at our institution and those referred from outside suggest that operative fixation is a useful modality that is likely underused.

Sol–gel synthesis of tantalum oxide and phosphonic acid-modified carbon nanotubes composite coatings on titanium surfaces

International Nuclear Information System (INIS)

Maho, Anthony; Detriche, Simon; Delhalle, Joseph; Mekhalif, Zineb

2013-01-01

composite coatings on titanium plates by sol–gel co-deposition. ► Synthesis and incorporation of MWCNTs bearing bisphosphonic acid moieties. ► Stronger “tantalum capture agent” effect of phosphonic-modified MWCNTs comparing to oxidized ones. ► Bioactivity of the resulting biomaterial qualitatively assessed by in vitro growth tests of hydroxyapatite

Sol–gel synthesis of tantalum oxide and phosphonic acid-modified carbon nanotubes composite coatings on titanium surfaces

Energy Technology Data Exchange (ETDEWEB)

Maho, Anthony [Laboratory of Chemistry and Electrochemistry of Surfaces, University of Namur (FUNDP), Rue de Bruxelles 61, B-5000 Namur (Belgium); Fonds pour la Formation à la Recherche dans l' Industrie et dans l' Agriculture (FRIA), Rue d' Egmont 5, B-1000 Bruxelles (Belgium); Detriche, Simon; Delhalle, Joseph [Laboratory of Chemistry and Electrochemistry of Surfaces, University of Namur (FUNDP), Rue de Bruxelles 61, B-5000 Namur (Belgium); Mekhalif, Zineb, E-mail: zineb.mekhalif@fundp.ac.be [Laboratory of Chemistry and Electrochemistry of Surfaces, University of Namur (FUNDP), Rue de Bruxelles 61, B-5000 Namur (Belgium)

2013-07-01

/carbon nanotube composite coatings on titanium plates by sol–gel co-deposition. ► Synthesis and incorporation of MWCNTs bearing bisphosphonic acid moieties. ► Stronger “tantalum capture agent” effect of phosphonic-modified MWCNTs comparing to oxidized ones. ► Bioactivity of the resulting biomaterial qualitatively assessed by in vitro growth tests of hydroxyapatite.

Valence electronic structure of tantalum carbide and nitride

Institute of Scientific and Technical Information of China (English)

FAN; ChangZeng

2007-01-01

The valence electronic structures of tantalum carbide (TaC) and tantalum nitride (TaN) are studied by using the empirical electronic theory (EET). The results reveal that the bonds of these compounds have covalent, metallic and ionic characters. For a quantitative analysis of the relative strength of these components, their ionicities have been calculated by implanting the results of EET to the PVL model. It has been found that the ionicity of tantalum carbide is smaller than that of tantalum nitride. The EET results also reveal that the covalent electronic number of the strongest bond in the former is larger than that of the latter. All these suggest that the covalent bond of TaC is stronger than that of TaN, which coincides to that deduced from the first-principles method.……

Valence electronic structure of tantalum carbide and nitride

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

@@ The valence electronic structures of tantalum carbide (TaC) and tantalum nitride (TaN) are studied by using the empirical electronic theory (EET). The results reveal that the bonds of these compounds have covalent, metallic and ionic characters. For a quantitative analysis of the relative strength of these components, their ionicities have been calculated by implanting the results of EET to the PVL model. It has been found that the ionicity of tantalum carbide is smaller than that of tantalum nitride. The EET results also reveal that the covalent electronic number of the strongest bond in the former is larger than that of the latter. All these suggest that the covalent bond of TaC is stronger than that of TaN, which coincides to that deduced from the first-principles method.

Efficacy of Tantalum Tungsten Alloys for Diffusion Barrier Applications

Science.gov (United States)

Smathers, D. B.; Aimone, P. R.

2017-12-01

Traditionally either Niobium, Tantalum or a combination of both have been used as diffusion barriers in Nb3Sn Multi-filament wire. Vanadium has also been used successfully but the ultimate RRR of the copper is limited unless an external shell of Niobium is included. Niobium is preferred over Tantalum when alternating current losses are not an issue as the Niobium will react to form Nb3Sn. Pure Tantalum tends to deform irregularly requiring extra starting thickness to ensure good barrier qualities. Our evaluations showed Tantalum lightly alloyed with 3 wt% Tungsten is compatible with the wire drawing process while deforming as well as or better than pure Niobium. Ta3wt%W has been processed as a single barrier and as a distributed barrier to fine dimensions. In addition, the higher modulus and strength of the Tantalum Tungsten alloy improves the overall tensile properties of the wire.

Uptake and retention of insufflated tantalum by lymph nodes

International Nuclear Information System (INIS)

Kilpper, R.W.; Bianco, A.; Gibb, F.R.; Landman, S.; Morrow, P.E.

1976-01-01

A nonsacrifice, radiographic technique is presented for evaluating the lymph node uptake of radiographically dense materials from the lungs of beagle dogs into which the material was insufflated. With tantalum as the contrast agent, lymph nodes sometimes become visible within 2 days after exposure when the insufflation resulted in radiographic ''alveolarization'' of some of the tantalum. Localization of the material within the nodes was observed in subsequent radiographs as well as persistent retention after as much as 1 year. Through the use of preinsufflation control films and tantalum foils of varying thickness, densitometric methods for determining the amount of tantalum within the lymph nodes are being investigated. Tantalum-182 is being used to follow the lung retention of the material as well as to verify estimates of burdens in harvested nodes. Preliminary lymphokinetic data are presented from experiments utilizing powders of 1 and 5 μm (mean) particle sizes

Extraction of Tantalum from locally sourced Tantalite using ...

African Journals Online (AJOL)

acer

Extraction of Tantalum from locally sourced Tantalite using ... ABSTRACT: The ability of polyethylene glycol solution to extract tantalum from locally .... metal ion in question by the particular extractant. ... Loparite, a rare-earth ore (Ce, Na,.

Tantalum high-temperature oxidation kinetics

International Nuclear Information System (INIS)

Grigor'ev, Yu.M.; Sarkisyan, A.A.; Merzhanov, A.G.

1981-01-01

Kinetics of heat release and scale growth during tantalum oxidation within 650-1300 deg C temperature range in oxygen-containing media is investigated. Kinetic equations and temperature and pressure dependences of constants are ound Applicability of the kinetic Lorie mechanism for the description of the tantalum oxidation kinetics applicably to rapid-passing processes is shown. It is stated that the process rate (reaction ability) is determined by adsorption desorption factors on the external surface of the ''protective'' oxide for the ''linear'' oxidation stage [ru

Modeling the mechanical behavior of tantalum

International Nuclear Information System (INIS)

Lee, B.J.; Ahzi, S.

1997-01-01

A crystal plasticity model is proposed to simulate the large plastic deformation and texture evolution in tantalum over a wide range of strain rates. In the model, a modification of the viscoplastic power law for slip and a Taylor interaction law for polycrystals are employed, which account for the effects of strain hardening, strain-rate hardening, and thermal softening. A series of uniaxial compression tests in tantalum at strain rates ranging from 10 -3 to 10 4 s -1 were conducted and used to verify the model's simulated stress-strain response. Initial and evolved deformation textures were also measured for comparison with predicted textures from the model. Applications of this crystal plasticity model are made to examine the effect of different initial crystallographic textures in tantalum subjected to uniaxial compression deformation or biaxial tensile deformation

Evaluation of the optimal plate position for the fixation of supraglenoid tubercle fractures in warmbloods.

Science.gov (United States)

Frei, Sina; Geyer, Hans; Hoey, Seamus; Fuerst, Anton E; Bischofberger, Andrea S

2017-03-20

To determine scapular cortex thickness, distal scapular bone density and describe the exact suprascapular nerve course to evaluate the best plate position for the fixation of supraglenoid tubercle fractures in horses. Twelve equine cadaveric shoulders were examined with computed tomography. Computed tomography morphometry and density measurements (Hounsfield units [HU]) of the scapula were recorded. Statistical comparisons were made between the cranial and caudal aspects of the scapula. Dissection of each shoulder was performed and the suprascapular nerve course was described morphometrically and morphologically. The suprascapular nerve was found on the periosteum and embedded in connective tissue at the cranial aspect of the scapula. It ramified proximally and distally into the supraspinatus muscle, coursed caudolaterally at a median of 2 cm (1-2 cm) distal to the scapular spine and ramified proximally and distally into the infraspinatus muscle. The scapular cortex measurements (HU) cranially were significantly larger than caudally at most levels of the scapula. The bone density of the distal scapula cranially (651.3 ± 104.2) was significantly lower than caudally (745.7 ± 179.1). For surgical access to the supraglenoid tubercle, knowledge of the anatomy is important. It is easiest to avoid the suprascapular nerve at the most cranial aspect of the scapula, where it has not yet ramified. For a stable fixation, knowledge of the characteristics of the equine scapula, such as scapular cortex thickness, is important.

Reaction of tantalum-alkyne complexes with isocyanates or acyl cyanides

International Nuclear Information System (INIS)

Kataoka, Yasutaka; Oguchi, Yoshiyuki; Yoshizumi, Kazuyuki; Miwatashi, Seiji; Takai, Kazuhiko; Utimoto, Kiitiro

1992-01-01

Treatment of alkynes with low-valent tantalum derived from TiCl 5 and zinc produces tantalum-alkyne complexes (not isolated), which react in situ with phenyl isocyanate (or butyl isocyanate) to give (E)-α, β-unsaturated amides stereoselectively. The tantalum-alkyne complexes also react with acyl cyanides in the presence of BF 3 ·OEt 2 to give α-cyanohydrins. In both reactions, filtration of the reaction mixture containing the tantalum-alkyne complexes before addition of isocyanates (or acyl cyanides) is indispensable to obtain good yields. (author)

Study of electrochemical behaviour of tantalum in molten alkali metal chlorides

International Nuclear Information System (INIS)

Bajmakov, A.N.; Ezrokhina, A.M.; Sashinina, O.A.; Shkol'nikov, S.N.

1985-01-01

Equilibrium potentials of metallic tantalum in the melt TaCl 5 +KCl-NaCl are studied. Are average degree of tantalum ion oxidation, which are in equilibrium with metallic tantalum, is determined. Anodic behaviour of tantalum in equimolar mixture of potassium and sodium chlorides with Ta and F ion additions is considered. An average degree of oxidation of Ta ions, which transfer into the melt, depending on current density, is determined. It is established that tantalum is dissolved in the regime of diffusional kinetics. It is shown that tantalum corrodes in equimolar mixture of potassium and sodiUm chlorides, at that, corrosion rate increases with introdUction of Ta and F ions into solution. The corrosion is of electrochemical nature and it proceeds in the regime of diffusional kinetics

Plate Fixation With Autogenous Calcaneal Dowel Grafting Proximal Fourth and Fifth Metatarsal Fractures: Technique and Case Series.

Science.gov (United States)

Seidenstricker, Chad L; Blahous, Edward G; Bouché, Richard T; Saxena, Amol

Metaphyseal and proximal diaphyseal fractures of the lateral column metatarsals can have problems with healing. In particular, those involving the fifth metatarsal have been associated with a high nonunion rate with nonoperative treatment. Although intramedullary screw fixation results in a high union rate, delayed healing and complications can occur. We describe an innovative technique to treat both acute and chronic injuries involving the metatarsal base from the metaphysis to the proximal diaphyseal bone of the fourth and fifth metatarsals. The surgical technique involves evacuation of sclerotic bone at the fracture site, packing the fracture site with compact cancellous bone, and plate fixation. In our preliminary results, 4 patients displayed 100% radiographic union at a mean of 4.75 (range 4 to 6) weeks with no incidence of refracture, at a mean follow-up point of 3.5 (range 1 to 5) years. The early results with our small series suggest that this technique is a useful treatment choice for metaphyseal and proximal diaphyseal fractures of the fourth and fifth metatarsals. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

External fixation is more suitable for intra-articular fractures of the distal radius in elderly patients

Science.gov (United States)

Ma, Chuang; Deng, Qiang; Pu, Hongwei; Cheng, Xinchun; Kan, Yuhua; Yang, Jing; Yusufu, Aihemaitijiang; Cao, Li

2016-01-01

The purpose of this study was to compare the functional outcomes, psychological impact, and complication rates associated with external fixation and volar or dorsal plating in relation to the functional parameters following treatment of intra-articular fractures of the distal radius (IFDR) in patients older than 65 years. We hypothesized that using volar or dorsal plating would improve functional outcomes, but that it would be associated with more complications and equivalent functional outcomes when compared with the external fixation group. A total of 123 consecutive patients suffering from IFDR were recruited into the study. The patients were measured for clinical, radiological, and psychosocial functioning outcomes and were followed up after 1 week and 3, 6 and 12 months. After 3 months, the plating group had better pronation (P=0.001), supination, (P=0.047) and extension (P=0.043) scores. These differences were somewhat attenuated by 6 months and disappeared at 1 year. The plating group had a greater occurrence of wound infection (P=0.043), tendonitis, (P=0.024) and additional surgery compared with the external fixation group. The only TNO-AZL Adult Quality of Life scores in the plating group that were lower than those in the external fixation group were in the “gross motor” category (walking upstairs, bending over, walking 500 yards; P=0.023). Internal fixation was more advantageous than external fixation in the early rehabilitation period; after 1 year the outcomes were similar. The plating group showed significantly higher levels of wound infection and tendonitis and had a greater need for additional surgeries. PMID:27408765

Dielectric properties of tantalum powder with broccoli-like morphology

Energy Technology Data Exchange (ETDEWEB)

Baba, Masahiko [Department of Energy Science and Technology, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Suzuki, Ryosuke O [Department of Energy Science and Technology, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)

2005-04-19

Metallic tantalum powder with broccoli-like morphology, consisting of spherical fine particles and of long rods or thin plates, was prepared in a hundred gram scale by calcium reduction of Ta{sub 2}O{sub 5} in molten CaCl{sub 2}. The properties as electrolytic capacitor were evaluated in comparison with commercial powder obtained by Na reduction and with powder consisting of only fine particles obtained by Ca reduction. The capacitance was larger than that of conventional powder with the same surface area, because the broccoli-like powder showed a strong resistance against shrinkage during high temperature annealing due to the framework of branches. The powder with new broccoli-like morphology can circumvent the conventional treatments for grain size control and gas removal.

Dielectric properties of tantalum powder with broccoli-like morphology

International Nuclear Information System (INIS)

Baba, Masahiko; Suzuki, Ryosuke O.

2005-01-01

Metallic tantalum powder with broccoli-like morphology, consisting of spherical fine particles and of long rods or thin plates, was prepared in a hundred gram scale by calcium reduction of Ta 2 O 5 in molten CaCl 2 . The properties as electrolytic capacitor were evaluated in comparison with commercial powder obtained by Na reduction and with powder consisting of only fine particles obtained by Ca reduction. The capacitance was larger than that of conventional powder with the same surface area, because the broccoli-like powder showed a strong resistance against shrinkage during high temperature annealing due to the framework of branches. The powder with new broccoli-like morphology can circumvent the conventional treatments for grain size control and gas removal

Tantalum oxide thin films as protective coatings for sensors

DEFF Research Database (Denmark)

Christensen, Carsten; Reus, Roger De; Bouwstra, Siebe

1999-01-01

Reactively sputtered tantalum oxide thin films have been investigated as protective coatings for aggressive media exposed sensors. Tantalum oxide is shown to be chemically very robust. The etch rate in aqueous potassium hydroxide with pH 11 at 140°C is lower than 0.008 Å h-l. Etching in liquids...... with pH values in the range from pH 2 to 11 have generally given etch rates below 0.04 Å h-l. On the other hand patterning is possible in hydrofluoric acid. Further, the passivation behaviour of amorphous tantalum oxide and polycrystalline Ta2O5 is different in buffered hydrofluoric acid. By ex situ...... annealing O2 in the residual thin-film stress can be altered from compressive to tensile and annealing at 450°C for 30 minutes gives a stress-free film. The step coverage of the sputter deposited amorphous tantalum oxide is reasonable, but metallization lines are hard to cover. Sputtered tantalum oxide...

Tantalum oxide thin films as protective coatings for sensors

DEFF Research Database (Denmark)

Christensen, Carsten; Reus, Roger De; Bouwstra, Siebe

1999-01-01

Reactively sputtered tantalum oxide thin-films have been investigated as protective coating for aggressive media exposed sensors. Tantalum oxide is shown to be chemically very robust. The etch rate in aqueous potassium hydroxide with pH 11 at 140°C is lower than 0.008 Å/h. Etching in liquids with p......H values in the range from pH 2-11 have generally given etch rates below 0.04 Å/h. On the other hand patterning is possible in hydrofluoric acid. Further, the passivation behaviour of amorphous tantalum oxide and polycrystalline Ta2O5 is different in buffered hydrofluoric acid. By ex-situ annealing in O2...... the residual thin-film stress can be altered from compressive to tensile and annealing at 450°C for 30 minutes gives a stress-free film. The step coverage of the sputter deposited amorphous tantalum oxide is reasonable, but metallisation lines are hard to cover. Sputtered tantalum oxide exhibits high...

Phenomenological effets of tantalum incorporation into diamond films: Experimental and first principle studies

Energy Technology Data Exchange (ETDEWEB)

Ullah, Mahtab, E-mail: mahtabullah@bzu.edu.pk [Department of Physics, Bahauddin Zakariya University Multan (Pakistan); Rana, Anwar Manzoor; Ahmad, E. [Department of Physics, Bahauddin Zakariya University Multan (Pakistan); Raza, Rizwan [Department of Physics, COMSATS Institute of Information Technology, Lahore-54000 (Pakistan); Hussain, Fayyaz [Department of Physics, Bahauddin Zakariya University Multan (Pakistan); Hussain, Akhtar; Iqbal, Muhammad [Theoretical Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)

2016-09-01

Graphical abstract: - Highlights: • Fabrication of tantalum incorporated diamonds films using HFCVD technique. • Decrease in resistivity by increasing tantalum content in diamond thin films. • Electronic structure calculations of tantalum incorporated diamonds films through VASP code. • A rise of bond length and bond angles by addition of tantalum in the diamond lattice. • Confirmation of decrease of resistivity by adding tantalum due to creation of impurity states in the bandgap. - Abstract: Tantalum (Ta) incorporated diamond films are synthesized on silicon substrate by chemical vapor deposition under gas mixture of CH{sub 4} + H{sub 2}. Characterizations of the resulting films indicate that morphology and resistivity of as-grown diamond films are significantly influenced by the process parameters and the amount of tantalum incorporated in the diamond films. XRD plots reveal that diamond films are composed of TaC along with diamond for higher concentration of tantalum and Ta{sub 2}C phases for lower concentration of tantalum. EDS spectra confirms the existence of tantalum in the diamond films. Resistivity measurements illustrate a sudden fall of about two orders of magnitude by the addition of tantalum in the diamond films. Band structure of Ta-incorporated diamond has been investigated based on density functional theory (DFT) using VASP code. Band structure calculations lead to the semiconducting behavior of Ta-incorporated diamond films because of the creation of defects states inside the band gap extending towards conduction band minimum. Present DFT results support experimental trend of resistivity that with the incorporation of tantalum into diamond lattice causes a decrease in the resistivity of diamond films so that tantalum-incorporated diamond films behave like a good semiconductor.

Contributions of retinal input and phenomenal representation of a fixation object to the saccadic gap effect.

Science.gov (United States)

Ueda, Hiroshi; Takahashi, Kohske; Watanabe, Katsumi

2013-04-19

The saccadic "gap effect" refers to a phenomenon whereby saccadic reaction times (SRTs) are shortened by the removal of a visual fixation stimulus prior to target presentation. In the current study, we investigated whether the gap effect was influenced by retinal input of a fixation stimulus, as well as phenomenal permanence and/or expectation of the re-emergence of a fixation stimulus. In Experiment 1, we used an occluded fixation stimulus that was gradually hidden by a moving plate prior to the target presentation, which produced the impression that the fixation stimulus still remained and would reappear from behind the plate. We found that the gap effect was significantly weakened with the occluded fixation stimulus. However, the SRT with the occluded fixation stimulus was still shorter in comparison to when the fixation stimulus physically remained on the screen. In Experiment 2, we investigated whether this effect was due to phenomenal maintenance or expectation of the reappearance of the fixation stimulus; this was achieved by using occluding plates that were an identical color to the background screen, giving the impression of reappearance of the fixation stimulus but not of its maintenance. The result showed that the gap effect was still weakened by the same degree even without phenomenal maintenance of the fixation stimulus. These results suggest that the saccadic gap effect is modulated by both retinal input and subjective expectation of re-emergence of the fixation stimulus. In addition to oculomotor mechanisms, other components, such as attentional mechanisms, likely contribute to facilitation of the subsequent action. Copyright © 2013 Elsevier Ltd. All rights reserved.

Tantalum strength model incorporating temperature, strain rate and pressure

Science.gov (United States)

Lim, Hojun; Battaile, Corbett; Brown, Justin; Lane, Matt

Tantalum is a body-centered-cubic (BCC) refractory metal that is widely used in many applications in high temperature, strain rate and pressure environments. In this work, we propose a physically-based strength model for tantalum that incorporates effects of temperature, strain rate and pressure. A constitutive model for single crystal tantalum is developed based on dislocation kink-pair theory, and calibrated to measurements on single crystal specimens. The model is then used to predict deformations of single- and polycrystalline tantalum. In addition, the proposed strength model is implemented into Sandia's ALEGRA solid dynamics code to predict plastic deformations of tantalum in engineering-scale applications at extreme conditions, e.g. Taylor impact tests and Z machine's high pressure ramp compression tests, and the results are compared with available experimental data. Sandia National Laboratories is a multi program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

The global tantalum industry and Sons of Gwalia Ltd

International Nuclear Information System (INIS)

Paull, D.

2002-01-01

Sons of Gwalia Ltd., in Perth Australia is a long-term supplier of tantalum (Ta), a valuable rare metal with adequate supply. Tantalum is soft and ductile with high melting and boiling points and a low co-efficient of thermal expansion. It has excellent capacity to store and release electrical charge and offers exceptional resistance to corrosion. Its' main use is in consumer electronics such as mobile phones, laptop computers, DVD players, personal video recorders and MP-3 players. For automotive electronics, tantalum is used for air-bags, audio systems, navigation systems, anti-lock break systems and under the hood vehicle management systems. The super alloy is also in demand by the aerospace industry and for turbine blades for power stations. The total demand of Tantalum in 2000 was 5 million lbs. Demand growth has increased steadily since 1993 with perhaps a slight increase in the past 5 years. Resources are estimated at a 125 year supply based on year 2000 production rates. 41 per cent of the world supply of tantalum is obtained from Australia, 13 per cent from Africa, 16 per cent from America, 22 per cent from Asia. The Greenbushes mine in Australia is the world's largest tantalum mine with 80 million lbs Ta, followed by Australia's Wodgina Mine with 50 million lbs Ta. Both mines are expected to be operational for the next 25 years. 12 figs

PREPARATION OF TANTALUM CARBIDE FROM AN ORGANOMETALLIC PRECURSOR

Directory of Open Access Journals (Sweden)

C. P. SOUZA

1999-03-01

Full Text Available In this work we have synthesized an organometallic oxalic precursor from tantalum oxide. This oxide was solubilized by heating with potassium hydrogen sulfate. In order to precipitate Ta2O5.nH2O, the fused mass obtained was dissolved in a sulfuric acid solution and neutralized with ammonia. The hydrated tantalum oxide precipitated was dissolved in an equimolar solution of oxalic acid/ammonium oxalate. The synthesis and the characterization of the tantalum oxalic precursor are described. Pyrolysis of the complex in a mixture of hydrogen and methane at atmospheric pressure was studied. The gas-solid reaction made it possible to obtain tantalum carbide, TaC, in the powder form at 1000oC. The natural sintering of TaC powder in an inert atmosphere at 1400°C during 10 hours, under inert atmosphere made it possible to densify the carbide to 96% of the theoretical value.

Force-dominated non-equilibrium oxidation kinetics of tantalum

International Nuclear Information System (INIS)

Kar, Prasenjit; Wang, Ke; Liang, Hong

2008-01-01

Using a combined electrochemical and mechanical manipulation technique, we compared the equilibrium and non-equilibrium oxidation processes and states of tantalum. Experimentally, a setup was developed with an electrochemical system attached to a sliding mechanical configuration capable of friction force measurement. The surface chemistry of a sliding surface, i.e., tantalum, was modified through the electrolyte. The mechanically applied force was fixed and the dynamics of the surface was monitored in situ through a force sensor. The formation of non-equilibrium oxidation states of tantalum was found in oxidation limiting environment of acetic acid. An oxidative environment of deionized water saturated with KCl was used as comparison. We proposed a modified Arrhenius-Eyring equation in which the mechanical factor was considered. We found that the mechanical energy induced the non-stable-state reactions leading to metastable oxidation states of tantalum. This equation can be used to predict mechanochemical reactions that are important in many industrial applications

Indications and outcome of Open Reduction and Internal Fixation of ...

African Journals Online (AJOL)

Background: Open reduction and internal fixation (ORIF) is a well-established surgical treatment of fractures worldwide. However, the indications and modes of stabilization of long bone fractures vary and are evolving .The general trend now is towards fixation with locked intramedullary nail (i.m nail) rather than plate and ...

Electronic structure and charge transport in nonstoichiometric tantalum oxide

Science.gov (United States)

Perevalov, T. V.; Gritsenko, V. A.; Gismatulin, A. A.; Voronkovskii, V. A.; Gerasimova, A. K.; Aliev, V. Sh; Prosvirin, I. A.

2018-06-01

The atomic and electronic structure of nonstoichiometric oxygen-deficient tantalum oxide TaO x<2.5 grown by ion beam sputtering deposition was studied. The TaO x film content was analyzed by x-ray photoelectron spectroscopy and by quantum-chemistry simulation. TaO x is composed of Ta2O5, metallic tantalum clusters and tantalum suboxides. A method for evaluating the stoichiometry parameter of TaO x from the comparison of experimental and theoretical photoelectron valence band spectra is proposed. The charge transport properties of TaO x were experimentally studied and the transport mechanism was quantitatively analyzed with four theoretical dielectric conductivity models. It was found that the charge transport in almost stoichiometric and nonstoichiometric tantalum oxide can be consistently described by the phonon-assisted tunneling between traps.

Titrimetric determination of tungsten in its alloys with tantalum

International Nuclear Information System (INIS)

Elinson, S.V.; Nezhnova, T.I.

1982-01-01

Titrimetric method of tungsten determination in tantalum base alloys has been developed. The method permits to determine 5-10% tungsten in the alloys with relative standard deviation of 0.013. The conditions are created by application of precipitation from homogeieous solutions or by the method of appearing reagents at pH values, which condition gradual hydrolytic precipitation of tantalum, and sodium tungstate remains in the solution and is not sorbed on tantalum hydroxide. After separation of tantalum oxide tungsten is precipitated in the form of lead tungstate by the excess of ti trated solution of lead salt during boiling and then at the background of lead tungstate precipitate without its separation lead excess is titrated by EDTA in the presence of mixed indicator-4-(2-pyridylazo)resocinol and xylenole orange in acetate buffer solution

Preparation of tantalum targets of known thicknesses

International Nuclear Information System (INIS)

Alexander, J.R.; Wirth, H.L.

1985-01-01

A series of carbon-backed tantalum targets were produced in a heavy ion sputtering system with a Penning ion source. The target thicknesses were then measured using the alpha-ray energy loss method. The resulting tabulated measurements were reproducible and make possible the production of carbon-backed tantalum targets with pre-determined thicknesses ranging from 20 μg/cm 2 to 1 mg/cm 2 . (orig.)

REVERSE ENGINEERING OF THE MITKOVIC TYPE INTERNAL FIXATOR FOR LATERAL TIBIAL PLATEAU

Directory of Open Access Journals (Sweden)

Nikola Vitković

2015-12-01

Full Text Available In orthopaedic surgery it is very important to use proper fixation techniques in the treatment of various medical conditions, i.e. bone fractures or other traumas. If an internal fixation method, such as plating, is required, it is possible to use Dynamic Compression Plates (DCP or Locking Compression Plates (LCP and their variants. For DCP implants it is important to match the patient's bone shape with the most possible accuracy, so that the most frequent implant bending is applied in the surgery. For LCP implants it is not so important to match the patient’s bone shape, but additional locking screw holes are required. To improve the geometrical accuracy and anatomical correctness of the shape of DCP and to improve the LCP geometric definition, new geometrical modelling methods for the Mitkovic type internal fixator for Lateral Tibia Plateau are developed and presented in this research. The presented results are quite promising; it can be concluded that these methods can be applied to the creation of geometrical models of internal fixator customized for the given patient or optimized for a group of patients with required geometrical accuracy and morphological correctness.

Producing tantalum or columbium powder

International Nuclear Information System (INIS)

Rerat, C.F.

1979-01-01

A process is described for the production of tantalum or columbium powder with a high yield within a desired range of particle sizes. A molten salt bath of a double salt comprising either an alkali metal tantalum fluoride or an alkali metal columbium fluoride and a relatively large amount of alkali metal halide diluent salt to act as a heat sink is initially maintained at a temperature a little above the liquidus temperature of the salt mixture. A liquid alkali metal at a comparatively low temperature is added to the continuously stirred bath at a high mass flow rate, and reduces the double salt, producing tantalum or columbium. The reaction is exothermic and causes the temperature to rise rapidly to a desired final reaction temperature within the range 760 to 1000 0 . The liquid alkali metal is thereafter fed at a high mass flow rate to complete the reaction quickly at the final reaction temperature. Forced cooling at a heat extraction rate not less than 42 kilojoules/min./kg. of double salt is used during at least a portion of the reaction cycle at a rate sufficient to maintain the final reaction temperature within a desired range. (author)

Bacterial adherence to tantalum versus commonly used orthopedic metallic implant materials.

Science.gov (United States)

Schildhauer, Thomas A; Robie, Bruce; Muhr, Gert; Köller, Manfred

2006-07-01

Evaluation of bacterial adhesion to pure tantalum and tantalum-coated stainless steel versus commercially pure titanium, titanium alloy (Ti-6Al-4V), and grit-blasted and polished stainless steel. Experimental in vitro cell culture study using Staphylococcus aureus and Staphylococcus epidermidis to evaluate qualitatively and quantitatively bacterial adherence to metallic implants. A bacterial adhesion assay was performed by culturing S. aureus (ATCC 6538) and S. epidermidis (clinical isolate) for one hour with tantalum, tantalum-coated stainless steel, titanium, titanium alloy, grit-blasted and polished stainless steel metallic implant discs. Adhered living and dead bacteria were stained using a 2-color fluorescence assay. Adherence was then quantitatively evaluated by fluorescence microscopy and digital image processing. Qualitative adherence of the bacteria was analyzed with a scanning electron microscope. The quantitative data were related to the implant surface roughness (Pa-value) as measured by confocal laser scanning microscopy. Bacterial adherence of S. aureus varied significantly (p = 0.0035) with the type of metallic implant. Pure tantalum presented with significantly (p titanium alloy, polished stainless steel, and tantalum-coated stainless steel. Furthermore, pure tantalum had a lower, though not significantly, adhesion than commercially pure titanium and grit-blasted stainless steel. Additionally, there was a significantly higher S. aureus adherence to titanium alloy than to commercially pure titanium (p = 0.014). S. epidermidis adherence was not significantly different among the tested materials. There was no statistically significant correlation between bacterial adherence and surface roughness of the tested implants. Pure tantalum presents with a lower or similar S. aureus and S. epidermidis adhesion when compared with commonly used materials in orthopedic implants. Because bacterial adhesion is an important predisposing factor in the development of

Evaluation of Bone Atrophy After Treatment of Forearm Fracture Using Nonlinear Finite Element Analysis: A Comparative Study of Locking Plates and Conventional Plates.

Science.gov (United States)

Matsuura, Yusuke; Rokkaku, Tomoyuki; Suzuki, Takane; Thoreson, Andrew Ryan; An, Kai-Nan; Kuniyoshi, Kazuki

2017-08-01

Forearm diaphysis fractures are usually managed by open reduction internal fixation. Recently, locking plates have been used for treatment. In the long-term period after surgery, some patients present with bone atrophy adjacent to the plate. However, a comparison of locking and conventional plates as a cause of atrophy has not been reported. The aim of this study was to investigate long-term bone atrophy associated with use of locking and conventional plates for forearm fracture treatment. In this study we included 15 patients with forearm fracture managed by either locking or conventional plates and with more than 5 years of follow-up. Computed tomographic imaging of both forearms was performed to assess bone thickness and local bone mineral density and to predict bone strength without plate reinforcement based on finite element analysis. Mean patient age at surgery was 48.0 years. Eight patients underwent reduction with fixed locking plates and were followed up for a mean of 79.5 months; the remaining 7 patients were treated with conventional plates and were followed up for a mean of 105.0 months. Compared with the conventional plate group, the locking plate group had the same fractured limb-contralateral limb ratio of cortex bone thickness, but had significantly lower ratios of mineral density adjacent to the plate and adjusted bone strength. This study demonstrated bone atrophy after locking plate fixation for forearm fractures. Treatment plans for forearm fracture should take into consideration the impact of bone atrophy long after plate fixation. Therapeutic IV. Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Tantalum markers in radiography

International Nuclear Information System (INIS)

Aronson, A.S.; Jonsson, N.; Alberius, P.

1985-01-01

The biocompatibility of two types of radiopaque tantalum markers was evaluated histologically. Reactions to pin markers (99.9% purity) and spherical markers (95.2% purity) were investigated after 3-6 weeks in rabbits and 5-48 weeks in children with abnormal growth. Both marker types were firmly attached to bone trabeculae; this was most pronounced in rabbit bone, and no adverse macroscopic reactions were observed. Microscopically, no reactions or only slight fibrosis of bone tissue were detected, while soft tissues only demonstrated a minor inflammatory reaction. Nevertheless, the need for careful preparation and execution of marker implantations is stressed, and particularly avoidance iof the use of emery in sharpening of cannulae. The bioinertness of tantalum was reconfirmed as was its suitability for use as skeletal and soft tissue radiographic markers. (orig.)

Dynamic material properties of refractory metals: tantalum and tantalum/tungsten alloys

International Nuclear Information System (INIS)

Furnish, M.D.; Lassila, D.H.; Chhabildas, L.C.; Steinberg, D.J.

1996-01-01

We have made a careful set of impact wave-profile measurements (16 profiles) on tantalum and tantalum-tungsten alloys at relatively low stresses (to 15 GPa). Alloys used were Ta 96.5 W 3.5 and Ta 86.5 W 13.5 (wt%) with oxygen contents of 30 endash 70 ppm. Information available from these experiments includes Hugoniot, elastic limits, loading rates, spall strength, unloading paths, reshock structure and specimen thickness effects. Hugoniot and spall properties are illustrated, and are consistent with expectations from earlier work. Modeling the tests with the Steinberg-Guinan-Lund rate-dependent material model provides for an excellent match of the shape of the plastic loading wave. The release wave is not well modeled due to the absence of the dynamic Bauschinger effect. There is also a discrepancy between experiments and calculations regarding the relative timing of the elastic and plastic waves that may be due to texture effects. copyright 1996 American Institute of Physics

Longitudinal recovery following distal radial fractures managed with volar plate fixation.

Science.gov (United States)

Stinton, S B; Graham, P L; Moloney, N A; Maclachlan, L R; Edgar, D W; Pappas, E

2017-12-01

To synthesise the literature and perform a meta-analysis detailing the longitudinal recovery in the first two years following a distal radius fracture (DRF) managed with volar plate fixation. Three databases were searched to identify relevant articles. Following eligibility screening and quality assessment, data were extracted and outcomes were assimilated at the post-operative time points of interest. A state-of-the-art longitudinal mixed-effects meta-analysis model was employed to analyse the data. The search identified 5698 articles, of which 46 study reports met the selection criteria. High levels of disability and impairment were reported in the immediate post-operative period with subsequently a rapid initial improvement followed by more gradual improvement for up to one year. The results highlight that the period associated with the greatest physical recovery is in the first three months and suggest that the endpoint of treatment outcomes is best measured at one year post-surgery. Clinically meaningful improvements in outcomes can be expected for 12 months, after which progress plateaus and reaches normal values. This paper adopted a novel approach to meta-analyses in that the research question was of a longitudinal nature, which required a unique method of statistical analysis. Cite this article: Bone Joint J 2017;99-B:1665-76. ©2017 The British Editorial Society of Bone & Joint Surgery.

Relationship between plate removal and Soong grading following surgery for fractured distal radius

NARCIS (Netherlands)

Selles, Caroline A.; Reerds, Sam T. H.; Roukema, Gert; van der Vlies, Kees H.; Cleffken, Berry I.; Schep, Niels W. L.

2018-01-01

The aim of this study was to determine the relationship between volar plate removal and the Soong classification following fixation for fractured distal radius. In this retrospective cohort study, all consecutive patients who had volar plate fixation for a distal radius fracture in 2011-2015 were

Fabrication of a Tantalum-Based Josephson Junction for an X-Ray Detector

Science.gov (United States)

Morohashi, Shin'ichi; Gotoh, Kohtaroh; Yokoyama, Naoki

2000-06-01

We have fabricated a tantalum-based Josephson junction for an X-ray detector. The tantalum layer was selected for the junction electrode because of its long quasiparticle lifetime, large X-ray absorption efficiency and stability against thermal cycling. We have developed a buffer layer to fabricate the tantalum layer with a body-centered cubic structure. Based on careful consideration of their superconductivity, we have selected a niobium thin layer as the buffer layer for fabricating the tantalum base electrode, and a tungsten thin layer for the tantalum counter electrode. Fabricated Nb/AlOx-Al/Ta/Nb and Nb/Ta/W/AlOx-Al/Ta/Nb Josephson junctions exhibited current-voltage characteristics with a low subgap leakage current.

Open reduction and cranial bone plate fixation of fractures involving the distal aspect of the radius and ulna in miniature- and toy-breed dogs: 102 cases (2008-2015).

Science.gov (United States)

De Arburn Parent, Rebecca; Benamou, Jérôme; Gatineau, Matthieu; Clerfond, Pierre; Planté, Jérôme

2017-06-15

OBJECTIVE To determine outcomes and complication rates of open reduction and cranial bone plate fixation of fractures involving the distal aspect of the radius and ulna in miniature- and toy-breed dogs. DESIGN Retrospective case series. ANIMALS 102 miniature- and toy-breed dogs (105 fractures) weighing ≤ 7 kg (15.4 lb) that had undergone open reduction and cranial bone plate fixation of a fracture involving the distal aspect of the radius and ulna from 2008 through 2015. PROCEDURES Medical records were reviewed and information extracted regarding dog and fracture characteristics, surgical variables, and follow-up examination data (including postoperative complications). Postoperative radiographs were examined for distal fragment size, implant placement, apposition, alignment, and healing stage. A long-term follow-up questionnaire was completed by telephone interview with dog owners at least 6 months after surgery. RESULTS Mean length of the distal bone fragment in all fractures was 19.2 mm, with a mean distal-to-total radial length ratio of 0.21. At last follow-up examination (typically 6 weeks after surgery), 97 (95%) dogs had no signs of lameness; minor lameness was identified in 5 (5%) dogs. Complications developed in 26 (25%) fractures (23 [22%] minor and 3 [3%] major complications). Sixty-eight of 71 (96%) owners rated the overall and long-term outcome as excellent and 3 (4%) as good; 68 of 71 (96%) dogs reportedly had no signs of residual lameness. CONCLUSIONS AND CLINICAL RELEVANCE Open reduction and cranial bone plate fixation for the treatment of radius-ulna fractures in miniature- and toy-breed dogs provided an excellent outcome with a low complication rate.

International Thermonuclear Experimental Reactor (ITER) divertor plate performance and lifetime considerations

International Nuclear Information System (INIS)

Mattas, R.F.

1990-03-01

The ITER divertor plate performance during the technology phase of operation has been analyzed. High-Z materials, such as tungsten and tantalum, have been considered as plasma side materials, and refractory metal alloys, Ta-10W, TZM, Nb-1Zr, and V-15Cr-5Ti, plus copper alloys have been considered as the structural materials. The fatigue lifetime have been predicted for structural plates and for duplex plates with the plasma side material bonded to the structure. The results indicate that refractory alloys have a comparable or improved performance to copper alloys. Peak allowable heat fluxes for these analyses are in the range of 15--20 MW/m 2 for 2 mm thick structural plates and 7--11 MW/m 2 for 4 mm thick duplex plates. 4 refs., 55 figs., 6 tabs

Open reduction and internal fixation of osteoporotic acetabular fractures through the ilio-inguinal approach: use of buttress plates to control medial displacement of the quadrilateral surface.

Science.gov (United States)

Peter, Robin E

2015-01-01

The number of acetabular fractures in the geriatric population requiring open reduction and internal fixation is increasing. Fractures with medial or anterior displacement are the most frequent types, and via the ilio-inguinal approach buttress plates have proved helpful to maintain the quadrilateral surface or medial acetabular wall. Seven to ten hole 3.5 mm reconstruction plates may be used as buttress plates, placed underneath the usual pelvic brim plate. This retrospective study presents our results with this technique in 13 patients at a minimum follow-up of 12 months (average, 31 months). 85% of the patients had a good result. The early onset of post-traumatic osteoarthritis necessitated total hip arthroplasty in two patients (15%) at 12 and 18 months follow-up, respectively. This treatment option should be considered in the surgeon's armamentarium when fixing these challenging cases. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biomechanical comparison of double-row locking plates versus single- and double-row non-locking plates in a comminuted metacarpal fracture model.

Science.gov (United States)

Gajendran, Varun K; Szabo, Robert M; Myo, George K; Curtiss, Shane B

2009-12-01

Open or unstable metacarpal fractures frequently require open reduction and internal fixation. Locking plate technology has improved fixation of unstable fractures in certain settings. In this study, we hypothesized that there would be a difference in strength of fixation using double-row locking plates compared with single- and double-row non-locking plates in comminuted metacarpal fractures. We tested our hypothesis in a gap metacarpal fracture model simulating comminution using fourth-generation, biomechanical testing-grade composite sawbones. The metacarpals were divided into 6 groups of 15 bones each. Groups 1 and 4 were plated with a standard 6-hole, 2.3-mm plate in AO fashion. Groups 2 and 5 were plated with a 6-hole double-row 3-dimensional non-locking plate with bicortical screws aimed for convergence. Groups 3 and 6 were plated with a 6-hole double-row 3-dimensional locking plate with unicortical screws. The plated metacarpals were then tested to failure against cantilever apex dorsal bending (groups 1-3) and torsion (groups 4-6). The loads to failure in groups 1 to 3 were 198 +/- 18, 223 +/- 29, and 203 +/- 19 N, respectively. The torques to failure in groups 4 to 6 were 2,033 +/- 155, 3,190 +/- 235, and 3,161 +/- 268 N mm, respectively. Group 2 had the highest load to failure, whereas groups 5 and 6 shared the highest torques to failure (p row plates had equivalent bending and torsional stiffness, significantly higher than observed for the single-row non-locking plate. No other statistical differences were noted between groups. When subjected to the physiologically relevant forces of apex dorsal bending and torsion in a comminuted metacarpal fracture model, double-row 3-dimensional non-locking plates provided superior stability in bending and equivalent stability in torsion compared with double-row 3-dimensional locking plates, whereas single-row non-locking plates provided the least stability.

Work hardening and plastic equation of state of tantalum

International Nuclear Information System (INIS)

Gypen, L.A.; Aernoudt, E.; Deruyttere, A.

1983-01-01

The influence of cold deformation on the thermal and athermal components of the flow stress of tantalum was investigated. Up to high deformation levels the strain hardening is due only to the development of internal stress fields; the effective stress remains almost constant. The athermal strain hardening of tantalum is parabolic at low deformation levels (epsilon < 0.5) and linear at high deformation levels, as for other bcc metals. Hart's plastic equation of state is shown to be valid for tantalum at room temperature in the whole deformation range investigated (from epsilon = 0.005 to epsilon = 2.8). (author)

[Effectiveness of arthroscopic treatment of anterior cruciate ligament tibial eminence avulsion fracture with non-absorbable suture fixation combined with mini-plate].

Science.gov (United States)

Wang, Suiyuan; Xiao, Yang; Tong, Zuoming; Li, Guiqiu; Jiang, Juhua; Yao, Jinghui; Wu, Zhiyong; Li, Tengfei; Wu, Qun

2013-09-01

To evaluate the surgical techniques and effectiveness of arthroscopic treatment of anterior cruciate ligament (ACL) tibial eminence avulsion fracture with non-absorbable suture fixation combined with the miniplate. Between January 2009 and March 2012, 32 patients with ACL tibial eminence avulsion fractures were treated. There were 18 males and 14 females, aged 12-40 years (mean, 17.5 years). The injury causes included traffic accident injury in 15 cases, sport injury in 6 cases, and falling injury in 11 cases. The time from injury to operation ranged 7-18 days with an average of 9.5 days. Before operation, the results of Lachman test were all positive; the Lysholm score was 52.13 +/- 4.22 and the International Knee Documentation Committee (IKDC) score was 44.82 +/- 2.44. According to Meyers-McKeever classification criteria, there were 12 cases of type II and 20 cases of type III. After arthroscopic poking reduction of fracture, tibial eminence avulsion fractures were fixed with the Ethibond non-absorbable sutures bypass figure-of-eight tibial tunnel combined with the metacarpal and phalangeal mini-plate. Primary healing was obtained in all incisions; no joint infection or skin necrosis occurred after operation. All patients were followed up with an average time of 22.4 months (range, 12-50 months). The patients showed negative Lachman test at 12 weeks after operation. Except 3 patients having knee extension limitation at last follow-up, the knee extension range of motion (ROM) was normal in the other patients; the knee flexion ROM was normal in all patients. The Lysholm score and IKDC score were significantly improved to 94.19 +/- 0.93 and 94.35 +/- 1.22 at last follow-up, showing significant differences when compared with preoperative values (t = 55.080, P = 0.000; t = 101.715, P = 0.000). The arthroscopic treatment of ACL tibial eminence avulsion fracture with Ethibond non-absorbable suture fixation combined with mini-plate is an effective procedure with the

Advances in the chemical vapor deposition (CVD) of Tantalum

DEFF Research Database (Denmark)

Mugabi, James Atwoki; Eriksen, Søren; Christensen, Erik

2014-01-01

The chemical stability of tantalum in hot acidic media has made it a key material in the protection of industrial equipment from corrosion under such conditions. The Chemical Vapor Deposition of tantalum to achieve such thin corrosion resistant coatings is one of the most widely mentioned examples...

Multi-scale Modeling of Plasticity in Tantalum.

Energy Technology Data Exchange (ETDEWEB)

Lim, Hojun [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Battaile, Corbett Chandler. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Carroll, Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Buchheit, Thomas E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Boyce, Brad [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Weinberger, Christopher [Drexel Univ., Philadelphia, PA (United States)

2015-12-01

In this report, we present a multi-scale computational model to simulate plastic deformation of tantalum and validating experiments. In atomistic/ dislocation level, dislocation kink- pair theory is used to formulate temperature and strain rate dependent constitutive equations. The kink-pair theory is calibrated to available data from single crystal experiments to produce accurate and convenient constitutive laws. The model is then implemented into a BCC crystal plasticity finite element method (CP-FEM) model to predict temperature and strain rate dependent yield stresses of single and polycrystalline tantalum and compared with existing experimental data from the literature. Furthermore, classical continuum constitutive models describing temperature and strain rate dependent flow behaviors are fit to the yield stresses obtained from the CP-FEM polycrystal predictions. The model is then used to conduct hydro- dynamic simulations of Taylor cylinder impact test and compared with experiments. In order to validate the proposed tantalum CP-FEM model with experiments, we introduce a method for quantitative comparison of CP-FEM models with various experimental techniques. To mitigate the effects of unknown subsurface microstructure, tantalum tensile specimens with a pseudo-two-dimensional grain structure and grain sizes on the order of millimeters are used. A technique combining an electron back scatter diffraction (EBSD) and high resolution digital image correlation (HR-DIC) is used to measure the texture and sub-grain strain fields upon uniaxial tensile loading at various applied strains. Deformed specimens are also analyzed with optical profilometry measurements to obtain out-of- plane strain fields. These high resolution measurements are directly compared with large-scale CP-FEM predictions. This computational method directly links fundamental dislocation physics to plastic deformations in the grain-scale and to the engineering-scale applications. Furthermore, direct

Newly designed anterolateral and posterolateral locking anatomic plates for lateral tibial plateau fractures: a finite element study.

Science.gov (United States)

Chen, Pengbo; Lu, Hua; Shen, Hao; Wang, Wei; Ni, Binbin; Chen, Jishizhan

2017-02-23

Lateral column tibial plateau fracture fixation with a locking screw plate has higher mechanical stability than other fixation methods. The objectives of the present study were to introduce two newly designed locking anatomic plates for lateral tibial plateau fracture and to demonstrate their characteristics of the fixation complexes under the axial loads. Three different 3D finite element models of the lateral tibial plateau fracture with the bone plates were created. Various axial forces (100, 500, 1000, and 1500 N) were applied to simulate the axial compressive load on an adult knee during daily life. The equivalent maps of displacement and stress were output, and relative displacement was calculated along the fracture lines. The displacement and stresses in the fixation complexes increased with the axial force. The equivalent displacement or stress map of each fixation under different axial forces showed similar distributing characteristics. The motion characteristics of the three models differed, and the max-shear stress of trabecula increased with the axial load. These two novel plates could fix lateral tibial plateau fractures involving anterolateral and posterolateral fragments. Motions after open reduction and stable internal fixation should be advised to decrease the risk of trabecular microfracture. The relative displacement of the posterolateral fragments is different when using anterolateral plate and posterolateral plate, which should be considered in choosing the implants for different posterolateral plateau fractures.

Use of sulfoxides for extraction-gravimetric determination of niobium and tantalum

International Nuclear Information System (INIS)

Nikolaev, A.I.; Babkin, A.G.; Tkachenko, V.G.

1977-01-01

An extraction-gravimetrical technique has been developed for determination of niobium and tantalum. The technique permits simultaneous extraction of tantalum and its concentrating in the aqueous phase; the range of Ta concentrations determined is essentially wider than in case of the routine gravimetric methods. The technique is based upon the fact, that tantalum is extracted by sulfoxides from fluorine-sulphate solutions at lower concentration of Hf and at lower ratios between the volumes of organic and aqueous phases than niobium. Two subsequent extractions by 1M sulfoxide solutions provide for practically complete transfer of tantalum into the organic phase, whereas extraction of niobium is only 3-20%. Sufficient recovery of Ta and Nb from organic phases is provided by re-extraction by NH 4 F solution. The technique is suitable for niobium and tantalum determination at the ratios of their pentoxides from 1:100 to 100:1. The disturbing influence of Fe(3) is suppressed by reductions to Fe(2)

Biomechanical analysis of titanium fixation plates and screws in ...

African Journals Online (AJOL)

2015-08-10

Aug 10, 2015 ... values on fixative appliances were predicted by means of. 3D FEA. The highest ... such as poor resistance to torsional forces, poor rigidity, and poor stability in ... the adequacy of mathematical models to relate mechanical factors such as ... the risk of bacterial contamination, scarring, postoperative edema ...

Spectrographic determination of impurities in high-purity tantalum oxide and niobium oxide

International Nuclear Information System (INIS)

Anderson, S.T.G.; Russell, G.M.

1990-01-01

The development of spectrographic methods by direct current arc excitation and carrier distillation for the determination of impurities in tantalum and niobium oxides are described. Iron, silicon, aluminium, titanium, calcium, silver, tin, magnesium, and manganese can be determined in tantalum oxide and niobium oxide in concentrations ranging from 3 to 300 p.p.m. Niobium can be determined in tantalum oxide in concentrations ranging from 10 to 300 p.p.m. Tantalum cannot be determined in niobium oxide, and tungsten cannot be determined in either matrix as a result of the absence of sensitive lines in the spectra of these elements. Relative standard deviations of analyte element concentrations are in the region of 0,18 for tantalum oxide samples, and 0,13 for niobium oxide samples. A detailed laboratory method is included. 4 figs., 4 tabs., 3 refs

Fixed-angle plates in patella fractures - a pilot cadaver study

Directory of Open Access Journals (Sweden)

Wild M

2011-01-01

Full Text Available Abstract Objective Modified anterior tension wiring with K-wires and cannulated lag screws with anterior tension wiring are currently the fixation of choice for patellar fractures. Failure of fixation, migration of the wires, postoperative pain and resulting revision surgery, however, are not uncommon. After preliminary biomechanical testing of a new fixed-angle plate system especially designed for fixation of patella fractures the aim of this study was to evaluate the surgical and anatomical feasibility of implanting such a plate-device at the human patella. Methods In six fresh unfixed female cadavers without history of previous fractures around the knee (average age 88.8 years a bilateral fixed-angle plate fixation of the patella was carried out after previous placement of a transverse central osteotomy. Operative time, intra-operative problems, degree of retropatellar arthritis (following Outerbridge, quality of reduction and existence of any intraarticular screw placement have been raised. In addition, lateral and anteroposterior radiographs of all specimens were made. Results Due to the high average age of 88.8 years no patella showed an unimpaired retropatellar articular surface and all were severely osteoporotic, which made a secure fixation of the reduction forceps during surgery difficult. The operation time averaged 49 minutes (range: 36-65. Although in postoperative X-rays the fracture gap between the fragments was still visible, the analysis of the retropatellar surface showed no residual articular step or dehiscence > 0.5 mm. Also in a total of 24 inserted screws not one intraarticular malposition was found. No intraoperative complications were noticed. Conclusions Osteosynthesis of a medial third patella fracture with a bilateral fixed-angle plate-device is surgically and anatomically feasible without difficulties. Further studies have to depict whether the bilateral fixed-angle plate-osteosynthesis of the patella displays

Separation of niobium and tantalum by paper chromatography and their following spectrographic determination

International Nuclear Information System (INIS)

Moroshkina, T.M.; Peres Sanfiel', F.

1975-01-01

The paper presents the results of an investigation into the use of water-saturated furfural to separate niobium and tantalum in a 1:1 ratio by means of ascending paper chromatography. The influence of sulphuric acid, ammonium fluoride and hydrofluoric acid concentrations on the completeness of the niobium and tantalum separation was investigated, the extent of the separation being checked by a spectral method. The results indicate that the use of furfural creates favourable conditions for niobium and tantalum separation. The purest tantalum is obtained at concentrations of sulphuric acid 600 k/l, hydrofluoric acid 4.6% and ammonium fluoride 30 g/l. To obtain pure niobium the acid concentrations remain the same but the quantity of ammonium fluoride is doubled. The fluoride ion concentration has a significant effect on the completeness of niobium and tantalum separation. The variation coefficient for the niobium determination is 14%, for the tantalum determination 1O% (author)

Removal of internal fixation--the effect on patients' complaints: a study of 66 cases of removal of internal fixation after malleolar fractures

DEFF Research Database (Denmark)

Jacobsen, S; Honnens de Lichtenberg, M; Jensen, C M

1994-01-01

To estimate the effect of removal of internal fixation after treatment of malleolar fractures on postoperatively presented complaints, we retrospectively evaluated 66 patients by their records and by personal questionnaires. Of all the patients, 89.4% had one or more complaints. These were...... typically soreness over implant and cicatrix, reduced movement of the ankle joint, and strain-related pain. About 75% of these patients reported improvement after removal. The AO mode of fixation, i.e., typically by lateral semitubular plating and transsyndesmotic screw and a medial screw or pins...... period. We conclude that removal of internal fixation after malleolar fractures is indicated when common types of complaints are presented....

Delayed Foreign Body Reaction Caused by Bioabsorbable Plates Used for Maxillofacial Fractures

Directory of Open Access Journals (Sweden)

Hong Bae Jeon

2016-01-01

Full Text Available BackgroundBioabsorbable plates and screws are commonly used to reduce maxillofacial bones, particularly in pediatric patients because they degrade completely without complications after bone healing. In this study, we encountered eight cases of a delayed foreign body reaction after surgical fixation with bioabsorbable plates and screws.MethodsA total of 234 patients with a maxillofacial fracture underwent surgical treatment from March 2006 to October 2013, in which rigid fixation was achieved with the Inion CPS (Inion, Tampere, Finland plating system in 173 patients and Rapidsorb (Synthes, West Chester, PA, USA in 61 patients. Their mean age was 35.2 years (range, 15-84 years. Most patients were stabilized with two- or three-point fixation at the frontozygomatic suture, infraorbital rim, and anterior wall of the maxilla.ResultsComplications occurred in eight (3.4% of 234 patients, including palpable, fixed masses in six patients and focal swelling in two patients. The period from surgical fixation to the onset of symptoms was 9-23 months. Six patients with a mass underwent secondary surgery for mass removal. The masses contained fibrous tissue with a yellow, grainy, cloudy fluid and remnants of an incompletely degraded bioabsorbable plate and screws. Their histological findings demonstrated a foreign body reaction.ConclusionsInadequate degradation of bioabsorbable plates caused a delayed inflammatory foreign body reaction requiring secondary surgery. Therefore, it is prudent to consider the possibility of delayed complications when using bioabsorbable plates and surgeons must conduct longer and closer follow-up observations.

Stress analysis of implant-bone fixation at different fracture angle

Science.gov (United States)

Izzawati, B.; Daud, R.; Afendi, M.; Majid, MS Abdul; Zain, N. A. M.; Bajuri, Y.

2017-10-01

Internal fixation is a mechanism purposed to maintain and protect the reduction of a fracture. Understanding of the fixation stability is necessary to determine parameters influence the mechanical stability and the risk of implant failure. A static structural analysis on a bone fracture fixation was developed to simulate and analyse the biomechanics of a diaphysis shaft fracture with a compression plate and conventional screws. This study aims to determine a critical area of the implant to be fractured based on different implant material and angle of fracture (i.e. 0°, 30° and 45°). Several factors were shown to influence stability to implant after surgical. The stainless steel, (S. S) and Titanium, (Ti) screws experienced the highest stress at 30° fracture angle. The fracture angle had a most significant effect on the conventional screw as compared to the compression plate. The stress was significantly higher in S.S material as compared to Ti material, with concentrated on the 4th screw for all range of fracture angle. It was also noted that the screws closest to the intense concentration stress areas on the compression plate experienced increasing amounts of stress. The highest was observed at the screw thread-head junction.

A STUDY ON PROXIMAL HUMERAL FRACTURES STABILISED WITH PHILOS PLATE

Directory of Open Access Journals (Sweden)

Praveen Sivakumar K

2017-02-01

Full Text Available BACKGROUND Techniques for treating complex proximal humeral fractures vary and include fixations using tension bands, percutaneous pins, bone suture, T-plates, intramedullary nails, double tubular plates, hemiarthroplasty, plant tan humerus fixator plates, Polaris nails and blade plates. Complications of these techniques include cutout or back out of the screws and plates, avascular necrosis, nonunion, malunion, nail migration, rotator cuff impairment and impingement syndromes. Insufficient anchorage from conventional implants may lead to early loosening and failure, especially in osteoporotic bones. In general, nonoperative treatment of displaced three and four-part fractures of the proximal humerus leads to poor outcome due to intraarticular nature of injury and inherent instability of the fragments. Comminuted fractures of the proximal humerus are at risk of fixation failure, screw loosening and fracture displacement. Open reduction and internal fixation with conventional plate and screws has been associated with unacceptably high incidence of screw pull out. PHILOS (the proximal humeral internal locking system plate is an internal fixation system that enables angled stabilisation with multiple interlocking screws for fractures of the proximal humerus. MATERIALS AND METHODS 30 patients with proximal humerus fractures who were admitted in the Department of Orthopaedics, Government General Hospital, Kakinada, during the period November 2014 - November 2016 were taken up for study according to inclusion criteria. All patients were treated with PHILOS plate. These proximal humerus fractures were classified according to Neer’s classification. Patients were followed up at 6 weeks, 12 weeks and 6 months’ interval. Functional outcomes for pain, range of motion and muscle power and function were assessed using the Constant-Murley scoring system. Collected data analysed with independent t-test and ANNOVA test. RESULTS The outcome of the study was 1

HIP (hot isostatic pressing) sintering of Tantalum (Ta) and tantalum carbide (TaC) powder mixture: relations between microstructure and properties

International Nuclear Information System (INIS)

Valin, F.; Schnedecker, M.

1994-01-01

HIP sintering at 1630 C and 195 MPa, during 2 hours, can be used for complete densification of mixtures of commercial tantalum carbide and tantalum powders. HIPed material properties are depending upon initial compositions. For C/Ta ratios inferior to 80%, the monocarbide structure is preserved. A partial ordering of the carbon vacancies will result, for TaC(0.80), in microhardness maximization. The microstructurally homogenous TaC(0.45) shows an excellent toughness. 2 figs., 2 refs

Treatment of segmental tibial fractures with supercutaneous plating.

Science.gov (United States)

He, Xianfeng; Zhang, Jingwei; Li, Ming; Yu, Yihui; Zhu, Limei

2014-08-01

Segmental tibial fractures usually follow a high-energy trauma and are often associated with many complications. The purpose of this report is to describe the authors' results in the treatment of segmental tibial fractures with supercutaneous locking plates used as external fixators. Between January 2009 and March 2012, a total of 20 patients underwent external plating (supercutaneous plating) of the segmental tibial fractures using a less-invasive stabilization system locking plate (Synthes, Paoli, Pennsylvania). Six fractures were closed and 14 were open (6 grade IIIa, 2 grade IIIb, 4 grade II, and 2 grade I, according to the Gustilo classification). When imaging studies confirmed bone union, the plates and screws were removed in the outpatient clinic. Average time of follow-up was 23 months (range, 12-47 months). All fractures achieved union. Median time to union was 19 weeks (range, 12-40 weeks) for the proximal fractures and 22 weeks (range, 12-42 weeks) for the distal fractures. Functional results were excellent in 17 patients and good in 3. Delayed union of the fracture occurred in 2 patients. All patients' radiographs showed normal alignment. No rotational deformities and leg shortening were seen. No incidences of deep infection or implant failures occurred. Minor screw tract infection occurred in 2 patients. A new 1-stage protocol using supercutaneous plating as a definitive fixator for segmental tibial fractures is less invasive, has a lower cost, and has a shorter hospitalization time. Surgeons can achieve good reduction, soft tissue reconstruction, stable fixation, and high union rates using supercutaneous plating. The current patients obtained excellent knee and ankle joint motion and good functional outcomes and had a comfortable clinical course. Copyright 2014, SLACK Incorporated.

Preparation of potassium tantalum fluoride from tantalum hydroxide

International Nuclear Information System (INIS)

Silva, F.T. da; Espinola, A.; Dutra, A.J.B.

1987-01-01

Potassium tantalum fluoride (K 2 TaF 7 ) is an intermediary product in the processing of tantaliferous materials; it is the basic raw material for both reduction processes in use presently: reduction by metallic sodium and electrolysis in molten halides. It is normally obtained from a fluorotantalic acid solution to which potassium ions are added the precipitation of white acicular crystals of K 2 TaF 7 . The conditions for precipitation and recrystallization were studied, and crystal characterization were done by scanning electron microscopy, X-ray diffraction and thermogravimetric and thermodifferential analyses. (Author) [pt

Evaluation of Fibular Fracture Type vs Location of Tibial Fixation of Pilon Fractures.

Science.gov (United States)

Busel, Gennadiy A; Watson, J Tracy; Israel, Heidi

2017-06-01

Comminuted fibular fractures can occur with pilon fractures as a result of valgus stress. Transverse fibular fractures can occur with varus deformation. No definitive guide for determining the proper location of tibial fixation exists. The purpose of this study was to identify optimal plate location for fixation of pilon fractures based on the orientation of the fibular fracture. One hundred two patients with 103 pilon fractures were identified who were definitively treated at our institution from 2004 to 2013. Pilon fractures were classified using the AO/OTA classification and included 43-A through 43-C fractures. Inclusion criteria were age of at least 18 years, associated fibular fracture, and definitive tibial plating. Patients were grouped based on the fibular component fracture type (comminuted vs transverse), and the location of plate fixation (medial vs lateral) was noted. Radiographic outcomes were assessed for mechanical failures. Forty fractures were a result of varus force as evidenced by transverse fracture of the fibula and 63 were due to valgus force with a comminuted fibula. For the transverse fibula group, 14.3% mechanical complications were noted for medially placed plate vs 80% for lateral plating ( P = .006). For the comminuted fibular group, 36.4% of medially placed plates demonstrated mechanical complications vs 16.7% for laterally based plates ( P = .156). Time to weight bearing as tolerated was also noted to be significant between groups plated medially and laterally for the comminuted group ( P = .013). Correctly assessing the fibular component for pilon fractures provides valuable information regarding deforming forces. To limit mechanical complications, tibial plates should be applied in such a way as to resist the original deforming forces. Level of Evidence Level III, comparative study.

Computational modelling of long bone fractures fixed with locking plates - How can the risk of implant failure be reduced?

LENUS (Irish Health Repository)

Nassiri, M

2013-03-01

The Locking Compression Plate (LCP) is part of a new plate generation requiring an adapted surgical technique and new thinking about commonly used concepts of internal fixation using plates. Knowledge of the fixation stability provided by these new plates is very limited and clarification is still necessary to determine how the mechanical stability and the risk of implant failure can best be controlled.

Examination of the damage and failure response of tantalum and copper under varied shock loading conditions

Energy Technology Data Exchange (ETDEWEB)

Bronkhorst, Curt A [Los Alamos National Laboratory; Dennis - Koller, Darcie [Los Alamos National Laboratory; Cerreta, Ellen K [Los Alamos National Laboratory; Gray Ill, George T [Los Alamos National Laboratory; Bourne, Neil [AWE-ALDERMASTON

2010-12-16

A number of plate impact experiments have been conducted on high purity polycrystalline tantalum and copper samples using graded flyer plate configurations to alter the loading profile. These experiments are designed in a way so that a broad range of damage regimes are probed. The results show that the nucleation of damage primarily occurs at the grain boundaries of the materials. This affords us the opportunity to propose a porosity damage nucleation criterion which begins to account for the length scales of the microstructure (grain size distribution) and the mechanical response of the grain boundary regions (failure stress distribution). This is done in the context of a G-T-N type model for the ductile damage and failure response of both the materials examined. The role of micro-inertial effects on the porosity growth process is also considered.

Sacroiliac screw fixation for tile B fractures.

NARCIS (Netherlands)

Bosch, E.W. van den; Zwienen, C.M. van; Hoek van Dijke, G.A.; Snijders, C.J.; Vugt, A.B. van

2003-01-01

BACKGROUND: The purpose of this comparative cadaveric study was to investigate whether the stability of partially unstable pelvic fractures can be improved by combining plate fixation of the symphysis with a posterior sacroiliac screw. METHODS: In six specimens, a Tile B1 (open-book) pelvic fracture

The effects of fixation of the ulna to the radius in young foals

International Nuclear Information System (INIS)

Clem, M.F.; DeBowes, R.M.; Douglass, J.P.; Leipold, H.W.; Chalman, J.A.

1988-01-01

The effects of radioulnar fixation were studied in 21 Quarter horse foals by applying a bone plate to the caudal aspect of the proximal part of the ulna, with screws engaging both the radius and the ulna. The plates were applied at 1 month of age in six foals (group I), 5 months of age in six foals (group II), and 7 months of age in three foals (group III). Six foals underwent sham operations at 1 month of age to serve as controls (group IV). Ulnar dysplasia and elbow subluxation developed in all treated foals. The magnitude of ulnar dysplasia was inversely related to the patient's age at fixation and was accompanied by degenerative joint disease and lameness in foals undergoing fixation at 1 and 5 months of age. Removal of the fixation appliances 16 weeks after implantation in three foals from each of groups I and II failed to reverse the degree of ulnar dysplasia. Although foals undergoing fixation at 7 months of age (group III) were not lame, radiographic evidence of subluxation and subtle degenerative changes in the articular cartilage of the treated elbow did develop. Recommendations for avoidance of radioulnar fixation were developed from these observations

Improving greater trochanteric reattachment with a novel cable plate system.

Science.gov (United States)

Baril, Yannick; Bourgeois, Yan; Brailovski, Vladimir; Duke, Kajsa; Laflamme, G Yves; Petit, Yvan

2013-03-01

Cable-grip systems are commonly used for greater trochanteric reattachment because they have provided the best fixation performance to date, even though they have a rather high complication rate. A novel reattachment system is proposed with the aim of improving fixation stability. It consists of a Y-shaped fixation plate combined with locking screws and superelastic cables to reduce cable loosening and limit greater trochanter movement. The novel system is compared with a commercially available reattachment system in terms of greater trochanter movement and cable tensions under different greater trochanteric abductor application angles. A factorial design of experiments was used including four independent variables: plate system, cable type, abductor application angle, and femur model. The test procedure included 50 cycles of simultaneous application of an abductor force on the greater trochanter and a hip force on the femoral head. The novel plate reduces the movements of a greater trochanter fragment within a single loading cycle up to 26%. Permanent degradation of the fixation (accumulated movement based on 50-cycle testing) is reduced up to 46%. The use of superelastic cables reduces tension loosening up to 24%. However this last improvement did not result in a significant reduction of the grater trochanter movement. The novel plate and cables present advantages over the commercially available greater trochanter reattachment system. The plate reduces movements generated by the hip abductor. The superelastic cables reduce cable loosening during cycling. Both of these positive effects could decrease the risks related to grater trochanter non-union. Copyright © 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

Bronchography by tantalum aerosols, an experimental investigation of lung clearance and retention

International Nuclear Information System (INIS)

Causse, Andre.

1974-01-01

Lung clearance of tantalum used as contrast medium has been studied in three animal species: rat, monkey and cat. In rats and monkeys, 80 to 90 percent of the inhaled tantalum was removed with a half life of 10 to 30 hr, but the residual fraction was removed with a half life longer than 100 days; consequently persistent roentgenographic pictures could be observed. These results were in accordance with those obtained by other authors studying dogs and men (accidental inhalation of radioactive tantalum). In cats, about 98 percent was removed with a half life of 15 hr and the remaining fraction with a half life of 18 days. In the three species, the physiological lung clearance mechanisms did not seem disturbed. Microscopic examination showed the peribronchiolar localisation of remaining tantalum in rats and monkeys, with proliferation of granulomes and fibrotic reaction. These results must induce to the greatest care when using tantalum in man in order to outline peripheral airways [fr

Percutaneous Intramedullary Screw Fixation of Distal Fibula Fractures: A Case Series and Systematic Review

NARCIS (Netherlands)

Loukachov, Vladimir V.; Birnie, Merel F. N.; Dingemans, Siem A.; de Jong, Vincent M.; Schepers, Tim

2017-01-01

The current reference standard for unstable ankle fractures is open reduction and internal fixation using a plate and lag screws. This approach requires extensive dissection and wound complications are not uncommon. The use of intramedullary screw fixation might overcome these issues. The aim of our

Material removal mechanisms in electrochemical-mechanical polishing of tantalum

International Nuclear Information System (INIS)

Gao, F.; Liang, H.

2009-01-01

Material removal mechanisms in tantalum chemical-mechanical polishing (CMP) and electrochemical-mechanical polishing (ECMP) were investigated using the single frequency electrochemical impedance spectroscopy (EIS). Through measuring the impedance of the tantalum surface, the single frequency EIS scan made it possible to observe the CMP and ECMP processes in situ. The impedance results presented competing mechanisms of removal and formation of a surface oxide layer of tantalum. Analysis indicated that the thickness of the oxide layer formed during polishing was related to the mechanical power correlated to the friction force and the rotating speed. Furthermore, the rate of growth and removal of the oxide film was a function of the mechanical power. This understanding is beneficial for optimization of CMP and ECMP processes.

Photo field emission spectroscopy of the tantalum band structure

International Nuclear Information System (INIS)

Kleint, Ch.; Radon, T.

1978-01-01

Photo field emission (PFE) currents of clean and barium covered tantalum tips have been measured with single lines of the mercury arc spectrum and phase-sensitive detection. Field strength and work function were determined from Fowler-Nordheim plots of the FE currents. Shoulders in the PFE current-voltage characteristics could be correlated to transitions in the band structure of tantalum according to a recently proposed two-step PFE model. A comparison with the relativistic calculations of Mattheiss and the nonrelativistic bands of Petroff and Viswanathan shows that Mattheiss' bands are more appropriate. Beside direct transitions several nondirect transitions from the different features composing the upper two density of states maxima below the Fermi edge of tantalum have been found. (Auth.)

Biomechanical analysis of acromioclavicular joint dislocation treated with clavicle hook plates in different lengths.

Science.gov (United States)

Shih, Cheng-Min; Huang, Kui-Chou; Pan, Chien-Chou; Lee, Cheng-Hung; Su, Kuo-Chih

2015-11-01

Clavicle hook plates are frequently used in clinical orthopaedics to treat acromioclavicular joint dislocation. However, patients often exhibit acromion osteolysis and per-implant fracture after undergoing hook plate fixation. With the intent of avoiding future complications or fixation failure after clavicle hook plate fixation, we used finite element analysis (FEA) to investigate the biomechanics of clavicle hook plates of different materials and sizes when used in treating acromioclavicular joint dislocation. Using finite element analysis, this study constructed a model comprising four parts: clavicle, acromion, clavicle hook plate and screws, and used the model to simulate implanting different types of clavicle hook plates in patients with acromioclavicular joint dislocation. Then, the biomechanics of stainless steel and titanium alloy clavicle hook plates containing either six or eight screw holes were investigated. The results indicated that using a longer clavicle hook plate decreased the stress value in the clavicle, and mitigated the force that clavicle hook plates exert on the acromion. Using a clavicle hook plate material characterized by a smaller Young's modulus caused a slight increase in the stress on the clavicle. However, the external force the material imposed on the acromion was less than the force exerted on the clavicle. The findings of this study can serve as a reference to help orthopaedic surgeons select clavicle hook plates.

Biomechanical analysis of the fixation systems for anterior column and posterior hemi-transverse acetabular fractures.

Science.gov (United States)

Lei, Jianyin; Dong, Pengfei; Li, Zhiqiang; Zhu, Feng; Wang, Zhihua; Cai, Xianhua

2017-05-01

The aim of this study was to evaluate the biomechanical properties of common fixation systems for complex acetabular fractures. A finite element (FE) pelvic model with anterior column and posterior hemi-transverse acetabular fractures was created. Three common fixation systems were used to fix the posterior wall acetabular fractures: 1. Anterior column plate combined with posterior column screws (group I), 2. Anterior column plate combined with quadrilateral area screws (group II) and 3. Double-column plates (group III). And 600 N, representing the body weight, was loaded on the upper surface of the sacrum to simulate the double-limb stance. The amounts of total and relative displacements were compared between the groups. The total amount of displacement was 2.76 mm in group II, 2.81 mm in group III, and 2.83 mm in group I. The amount of relative displacement was 0.0078 mm in group II, 0.0093 mm in group III and 0.014 mm in group I. Our results suggested that all fixation systems enhance biomechanical stability significantly. Anterior column plate combined with quadrilateral area screws has quite comparable results to double column plates, they were superior to anterior column plate combined with posterior screws. Copyright © 2017 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

Development of technology of high-purity compounds of tantalum and niobium with octanol use

International Nuclear Information System (INIS)

Majorov, V.G.; Nikolaev, A.I.; Kopkov, V.K.; Baklanova, I.V.; Safonova, L.A.

2001-01-01

Effect of composition of solutions and extractant expenditure on tantalum and niobium distribution during extraction by octanol and purification of tantalum and niobium extracts from impurities was studied. Scheme was developed according to which samples of high-pure tantalum and niobium pentaoxides were prepared [ru

The Chemical Vapour Deposition of Tantalum - in long narrow channels

DEFF Research Database (Denmark)

Mugabi, James Atwoki

protective layers of tantalum because of the process’ ability to coat complex geometries and its relative ease to control. This work focuses on studying the CVD of tantalum in long narrow channels with the view that the knowledge gained during the project can be used to optimise the commercial coating...... and that there is a major change in morphology between 850 – 900 °C. The effects of system pressure and precursor partial pressure are also studied, and were found to have relevance to the tantalum distribution along the substrates but little effect on the structural morphology of the deposited layer. In the implemented...

Synthesis and characterization of tantalum organometallic complexes. Catalytic activity for olefins

International Nuclear Information System (INIS)

Baley, A.S.

1990-11-01

Synthesis of monoaryloxy (alcoxy) neopentyl compounds is investigated. The tantalum-oxygen bond is formed by two parallel ways from TaCl 5 or TaR 2 Cl 3 with R = neopentyl and the tantalum carbon bond from a neopentyl derivative of the main series. Some compounds were isolated and characterized by NMR, elemental analysis and sometimes X-ray structure, some others are characterized in solution only. Catalytic effect is tested by ethylene dimerization and olefin polymerization. Reactivity of tantalum aryloxy neopentyl in respect to complexing and chelating ligands is studied for preparation of neopentylidene complexes

Comparative study of bridge plate associated to the intramedullary pin and the dynamic compression plate on the experimental osteotomy fixation of femoral in rabbits (Oryctolagus cuniculus). Clinical, radiographic, histological and scintigraphy analyses; Estudo comparativo da placa em ponte associada ao pino intramedular e da placa de compressao dinamica na fixacao de osteotomia experimental em femur de coelhos (Oryctolagus cuniculus). Analises clinica, radiografica, histologica e cintilografica

Energy Technology Data Exchange (ETDEWEB)

Borges, Natalie Ferreira

2011-07-01

The objectives were to benchmark and monitor the fracture healing of femoral osteotomy in rabbits after fixation with dynamic compression plate and bridge plate associated with intramedullary pin. Were used 14 New Zealand rabbits, four months old with mean weight of 3.5 pounds, from the Experimental Farm Professor Helio Barbosa of the Veterinary School of Minas Gerais Federal Univ. (UFMG). The animals were randomly divided into two groups (I and II). All rabbits underwent osteotomy across the middle third of right femur. In the group I was made to fix the osteotomy with the bridge plate (BP) associated with intramedullary pin, introduced the technique of minimal invasion. In group II, we used dynamic compression plate (DCP) via the conventional approach. Both groups were evaluated clinical, radiographic, histologic and scintigraphic findings. Clinical assessments were performed weekly until the 12{sup th} postoperative week and radiographic examinations were performed before, immediately after, at 15, 30, 45, 60 and 90 days. The bone scintigraphy were performed before and at 20, 50 and 90 days after surgery to monitor the bone metabolism qualitatively and quantitatively. Observed perfusion and bone healing process. After 90 days of study, there was histopathologic evaluation of the osteotomized area and the insertion of screws. In the region of the osteotomy was observed predominance of trabecular bone in group I and group II, the predominance of bone osteons, compatible with the original bone. On insertion of the screws did not differ between groups and there was cortical discontinuity, little necrosis and local hemorrhage. The two types of fixation have led to consolidation within the scheduled period, maturing in early fixation with DCP fixation compared with BP. Scintigraphy demonstrated by the indices of activity and image characteristics, the process of bone healing was significantly greater in animals undergoing early fixation with DCP. (author)

Additively manufactured porous tantalum implants

NARCIS (Netherlands)

Wauthle, Ruben; Van Der Stok, Johan; Yavari, Saber Amin; Van Humbeeck, Jan; Kruth, Jean Pierre; Zadpoor, Amir Abbas; Weinans, Harrie; Mulier, Michiel; Schrooten, Jan

2015-01-01

The medical device industry's interest in open porous, metallic biomaterials has increased in response to additive manufacturing techniques enabling the production of complex shapes that cannot be produced with conventional techniques. Tantalum is an important metal for medical devices because of

Tribological performance of polycrystalline tantalum-carbide-incorporated diamond films on silicon substrates

Science.gov (United States)

Ullah, Mahtab; Rana, Anwar Manzoor; Ahmed, E.; Malik, Abdul Sattar; Shah, Z. A.; Ahmad, Naseeb; Mehtab, Ujala; Raza, Rizwan

2018-05-01

Polycrystalline tantalum-carbide-incorporated diamond coatings have been made on unpolished side of Si (100) wafer by hot filament chemical vapor deposition process. Morphology of the coatings has been found to vary from (111) triangular-facetted to predominantly (111) square-faceted by increasing the concentration of tantalum carbide. The results have been compared to those of a diamond reference coating with no tantalum content. An increase in roughness has been observed with the increase of tantalum carbide (TaC) due to change in morphology of the diamond films. It is noticed that roughness of the coatings increases as grains become more square-faceted. It is found that diamond coatings involving tantalum carbide are not as resistant as diamond films with no TaC content and the coefficient of friction for such coatings with microcrystalline grains can be manipulated to 0·33 under high vacuum of 10-7 Torr. Such a low friction coefficient value enhances tribological behavior of unpolished Si substrates and can possibly be used in sliding applications.

Displaced proximal humeral fractures: an Indian experience with locking plates

Directory of Open Access Journals (Sweden)

Aggarwal Sameer

2010-08-01

Full Text Available Abstract Background The treatment of displaced proximal humerus fractures, especially in elderly, remains controversial. The objective of this study was to evaluate functional outcome of locking plate used for fixation of these fractures after open reduction. We also attempted to evaluate the complications and predictors of loss of fixation for such an implant. Methods Over two and a half years, 56 patients with an acute proximal humerus fracture were managed with locking plate osteosynthesis. 47 of these patients who completed a minimum follow up of 1 year were evaluated using Constant score calculation. Statistical analysis was done using SPSS 16 and a p value of less than 0.05 was taken as statistically significant. Results The average follow up period was around 21.5 months. Outcomes were excellent in 17%, good in 38.5%, moderate in 34% while poor in 10.5%. The Constant score was poorer for AO-OTA type 3 fractures as compared to other types. The scores were also inferior for older patients (> 65 years old. Complications included screw perforation of head, AVN, subacromial impingement, loss of fixation, axillary nerve palsy and infection. A varus malalignment was found to be a strong predictor of loss of fixation. Conclusion Locking plate osteosynthesis leads to satisfactory functional outcomes in all the patients. Results are better than non locking plates in osteoporotic fractures of the elderly. However the surgery has steep learning curve and various complications could be associated with its use. Nevertheless we believe that a strict adherence to the principles of locking plate use can ensure good result in such challenging fractures.

An investigation of tantalum and niobium contents by nuclear technique

International Nuclear Information System (INIS)

Patmasiriwat, N.

1981-01-01

The objective of this experimental study was to find suitable nuclear techniques to determine the quantities of niobium and tantalum in columbite. The study has been performed by using radioisotope X-ray fluorescent technique (X RF) and neutron activation analysis (NAA). The results showed a good agreement between these two techniques. Nevertheless, with NAA, if there is uranium in the sample, the spectrum of niobium will be interfered. So practically, on the basis of accuracy and speed of determination, X-ray fluorescence is more suitable than NAA to determine the quantity of niobium while tantalum is preferable to use NAA. The detection limit of niobium and tantalum using the above techniques are 0.661% and 0.1 mg respectively

Outcome of 28 open pilon fractures with injury severity-based fixation.

Science.gov (United States)

Danoff, Jonathan R; Saifi, Comron; Goodspeed, David C; Reid, J Spence

2015-04-01

Open pilon fracture management and treatment poses a significant challenge to orthopedic surgeons. The purpose of this study was to determine patient outcomes for open pilon fractures based on wound complication and infection rates, as well as subjective outcome instruments. This was a retrospective consecutive case series of 28 fractures with Orthopaedic Trauma Association (OTA)-type 43-B and 43-C open pilon fractures. Mean length of follow-up was 36 months and minimum of 1 year. Ten fractures were Gustilo and Anderson grade IIIB, and the remaining fractures were grades I-IIIA. Patients were initially treated with spanning external fixation and staged wound debridement followed by osteosynthesis of the articular surface. Metaphyseal fixation was by either plate fixation or Ilizarov frame. The primary outcome was the incidence of deep tissue infection requiring surgery. Secondary outcomes included the incidence of other complications (nonunion, malunion, amputation) and functional outcomes (Short Musculoskeletal Functional Assessment Questionnaire and AAOS Foot and Ankle Questionnaire). Four patients developed deep tissue infections, three in the internal fixation group and one in the Ilizarov group, and all were treated successfully with staged debridement. There were two delayed unions required bone grafting, and infection-free union was ultimately achieved in all fractures. Two patients underwent arthrodesis secondary to post-traumatic arthritis, while no patients experienced malunions or amputations. The use of staged wound debridement in conjunction with either plate fixation or Ilizarov frame achieves low rates of wound infection and stable fixation after anatomic joint reconstruction for OTA-type 43-B and 43-C open pilon fractures.

Hydrogen adsorption on skeletal rhodium-tantalum electrodes-catalysts

International Nuclear Information System (INIS)

Tsinstevich, V.M.; Krejnina, N.M.

1975-01-01

Skeleton rhodium-tantalic catalyst electrodes with a tantalum mass percentage of 0 to 100 have been obtained by the methodology of Crupp and others. The hydrogen adsorption is studied through the method of removing the galvano-static and potentiodynamic curves of charging in sulfuric acid and potassium hydroxide. It has been discovered that the maximum adsorption ability relatively to the hydrogen can be observed in an alloy with a 5% tantalum contents. The energetic characteristics of the alloys are higher in alkali than in acid

Comparison of reconstruction plate screw fixation and percutaneous cannulated screw fixation in treatment of Tile B1 type pubic symphysis diastasis: a finite element analysis and 10-year clinical experience.

Science.gov (United States)

Yu, Ke-He; Hong, Jian-Jun; Guo, Xiao-Shan; Zhou, Dong-Sheng

2015-09-22

The objective of this study is to compare the biomechanical properties and clinical outcomes of Tile B1 type pubic symphysis diastasis (PSD) treated by percutaneous cannulated screw fixation (PCSF) and reconstruction plate screw fixation (RPSF). Finite element analysis (FEA) was used to compare the biomechanical properties between PCSF and RPSF. CT scan data of one PSD patient were used for three-dimensional reconstructions. After a validated pelvic finite element model was established, both PCSF and RPSF were simulated, and a vertical downward load of 600 N was loaded. The distance of pubic symphysis and stress were tested. Then, 51 Tile type B1 PSD patients (24 in the PCSF group; 27 in the RPSF group) were reviewed. Intra-operative blood loss, operative time, and the length of the skin scar were recorded. The distance of pubic symphysis was measured, and complications of infection, implant failure, and revision surgery were recorded. The Majeed scoring system was also evaluated. The maximum displacement of the pubic symphysis was 0.408 and 0.643 mm in the RPSF and PCSF models, respectively. The maximum stress of the plate in RPSF was 1846 MPa and that of the cannulated screw in PCSF was 30.92 MPa. All 51 patients received follow-up at least 18 months post-surgery (range 18-54 months). Intra-operative blood loss, operative time, and the length of the skin scar in the PCSF group were significantly different than those in the RPSF group. No significant differences were found in wound infection, implant failure, rate of revision surgery, distance of pubic symphysis, and Majeed score. PCSF can provide comparable biomechanical properties to RPSF in the treatment of Tile B1 type PSD. Meanwhile, PCSF and RPSF have similar clinical and radiographic outcomes. Furthermore, PCSF also has the advantages of being minimally invasive, has less blood loss, and has shorter operative time and skin scar.

Locking plates in distal humerus fractures: study of 43 patients

Directory of Open Access Journals (Sweden)

Gupta Rakesh Kumar

2013-08-01

Full Text Available 【Abstract】Objective: The treatment of multi-fragmentary, intraarticular fractures of the distal humerus is difficult, even in young patients with bone of good quality. Small distal fragment, diminished bone mineral quality and increased trauma-associated joint destruction make stable joint reconstruction more problematic. The anatomically preshaped locking plates allow angular stable fixation for these complex fractures. We evaluated functional results of patients treated with open reduction and internal fixation with distal humerus locking plates for complex distal hu-merus fractures. Methods: Forty-three consecutive patients with ar-ticular fractures of the distal humerus were treated by open reduction and internal fixation with AO distal humerus plate system and locking reconstruction plates. Forty patients were available for the final outcome analysis. According to AO/ASIF classification, there were 2 cases of type A2, 4 cases of type A3, 1 case of type B1, 1 case of type B2, 14 cases of type C1, 7 cases of type C2 and 11 cases of type C3. Open reduction with triceps splitting technique was used in all patients. The clinical and radiographic follow-up was performed and outcome measures included pain assessment, range of motion, and Mayo elbow performance score. Results: Forty patients were available for the final outcome analysis. There were 29 males and 11 females with an average age of 38.4 years (18-73 years. Clinical and ra-diological consolidation of the fracture was observed in all cases at an average of 11.6 weeks (9-14 weeks. The average follow-up was 12 months (10-18 months. Using the Mayo elbow performance score the results obtained were graded as excellent or good results in 33 patients (82.5%. One pa-tient had superficial infection, and 4 had myositis ossificans. There were no cases of primary malposition or secondary displacement, implant failure or ulnar neuropathy. Conclusion: Anatomically preshaped distal humerus locking

Minimally invasive percutaneous plate fixation of distal tibia fractures.

LENUS (Irish Health Repository)

Bahari, Syah

2007-10-01

We report a series of 42 patients reviewed at a mean of 19.6 months after treatment of distal tibial and pilon fractures using the AO distal tibia locking plate with a minimally invasive percutaneous plate osteosynthesis (MIPPO) technique. Mean time to union was 22.4 weeks. All fractures united with acceptable alignment and angulation. Two cases of superficial infection were noted, with one case of deep infection. Mean SF36 score was 85 and mean AOFAS score was 90 at a mean of 19 months follow-up. We report satisfactory outcomes with the use of the AO distal tibia locking plate in treatment of unstable distal tibial fractures. Eighty-nine percent of the patients felt that they were back to their pre injury status and 95% back to their previous employment.

New technique for fixing rib fracture with bioabsorbable plate.

Science.gov (United States)

Oyamatsu, Hironori; Ohata, Norihisa; Narita, Kunio

2016-09-01

Fixation of a bone fracture with a bioabsorbable plate made of poly-L-lactide and hydroxyapatite has received attention. We adopted this technique for a rib fracture by bending the plate into a U-shape and fixing it with suture through the holes in the mesh of the plate and holes that are drilled in the edge of the fractured rib. The suture is also wound around the plate. © The Author(s) 2016.

Effect of sputtering parameters and substrate composition on the structure of tantalum thin films

Energy Technology Data Exchange (ETDEWEB)

Hallmann, Lubica, E-mail: lubica.hallmann@zzm.uzh.c [Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zürich (Switzerland); Ulmer, Peter [Institute of Geochemistry and Petrology, ETH Zürich (Switzerland)

2013-10-01

The crystallographic properties of tantalum films deposited as a bioactive coating on Co–Cr–Mo and Ti–Al–Nb alloys have been investigated. The desired tough and ductile alpha phase of tantalum has been obtained by DC magnetron sputtering on Co–Cr–Mo and Ti–Al–Nb substrates. The thickness of the tantalum layer was between 20 and 600 nm. The crystallographic structure of tantalum thin film was dependent on the sputtering parameters such as DC power, bias voltage and gas impurities. Oxygen is an important factor for the stabilization of the tantalum alpha phase on Co–Cr–Mo substrate. The crystallographic structure and texture of tantalum thin films was found to be additionally dependent on the substrate composition. For Ti–Al–Nb substrate, oxygen content was not an important factor for the stabilization of the alpha phase. The observed shift of X-ray diffraction peaks to lower 2(θ) is an indication of stress evolving during the sputtering process and was dependent on bias voltage and oxygen content of the carrier gas.

Ilizarov external fixation versus plate osteosynthesis in the management of extra-articular fractures of the distal tibia.

Science.gov (United States)

Fadel, Mohamed; Ahmed, Mohamed Ali; Al-Dars, Ahmed Mounir; Maabed, Mustafa Ahmed; Shawki, Hashem

2015-03-01

The purpose of this study was to evaluate the outcome of Ilizarov external fixation (IE) versus dynamic compression plate (PO) in the management of extra-articular distal tibial fractures. Between 2010 and 2011, extra-articular distal tibial fractures in 40 consecutive patients met the inclusion criteria. They were classified according to AO classification fracture type A (A1, A2, and A3). In a randomized method, two equal groups were managed using either IE or PO. PO was performed using open reduction and internal fixation (ORIF) and DCP through anterolateral approach. IE was done using Ilizarov frame. For the PO group, non-weight bearing ambulation was permitted on the second postoperative day but partial weight bearing was permitted according to the progression in union criteria clinically and radiologically. For the IE group, weight bearing started as tolerated from the first postoperative day. Physiotherapy and pin-site care was performed by the patient themselves. Modified Mazur ankle score was applied to IE (excellent 10, good 10) and in PO (excellent 2, good 8, poor 6). Data were statically analysed using (Mann-Whitney test). The rate of healing in the IE group (average 130) was higher than the PO (average 196.5); plus, there were no cases of delayed union or nonunion in the IE group (p value 0.003). It was found that IE compared with PO provides provision of immediate weight bearing as tolerated following postoperative recovery, irrespective of radiological or clinical healing with no infection, deformity or non-union.

Experimental lumbar spine fusion with novel tantalum-coated carbon fiber implant

DEFF Research Database (Denmark)

Li, Haisheng; Zou, Xuenong; Woo, Charlotte

2007-01-01

the possibility of coating a biocompatible metal layer on top of the carbon fiber material, to improve its biological performance. Tantalum was chosen because of its bone compatibility, based on our previous studies. A novel spinal fusion cage was fabricated by applying a thin tantalum coating on the surface...

Effects of rigid fixation on the growing neurocranium of immature rabbits.

Science.gov (United States)

Sanus, Galip Zihni; Tanriverdi, Taner; Kacira, Tibet; Jackson, Ian T

2007-03-01

The improved intraoperative long-term skeletal stability achieved with rigid fixation techniques has led to their widespread popularity and application. However, experimental studies have revealed some drawbacks related to metallic implants and long-term results of clinical studies, especially in pediatric patients, has confirmed the results of experimental studies. Our aim in this experimental study using an infant rabbit model is to answer the following question: "Does short-term skeletal stability cause long-term growth inhibition?" Forty, 9-day-old New Zealand white albino rabbits were divided into four groups: 1) experimental, n=6: plated across the right coronal suture and two screws on each side of the left coronal suture; 2) re-operation, n=6: the same materials as group I were placed, and only the plate was removed at the end of 1 month; 3) sham, n=6: sham control with simulated surgery and two screws on each side of the left coronal suture; 4) control, n=2: no operation. The animals were killed 6 months after microplate application, and the skulls were evaluated both grossly and cephalometrically. Gross examination showed that the plates and the screws were covered by bony overgrowth and caused bony irregularity and regional bone degeneration. The parietal bones on the plated sides became striated and lost their concave shape. Cephalometric analysis demonstrated overt mastoid tip deviation toward, or shortening of cranionasal length on, the side with rigid fixation. We conclude from our study that rigid fixation during skeletal development causes growth retardation and should not be used in the growing child.

Application of biodegradable plates for treating pediatric mandibular fractures.

Science.gov (United States)

An, Jingang; Jia, Pengcheng; Zhang, Yi; Gong, Xi; Han, Xiaodong; He, Yang

2015-05-01

We assessed the clinical results of a biodegradable plate system for the internal fixation of mandibular fractures in children, and observed the imaging features of fracture healing and bone changes around the biodegradable plates and screws during follow-up. We enrolled 39 patients (22 male, 17 female, average age 4 years 10 months) with different mandibular fractures. We used 2.0-mm resorbable plates to repair the fractures. Postoperative follow-up ranged from 6 months to 5 years; average follow-up was 1 year 2 months. The outcome measures identified and assessed included facial symmetry, mouth opening, occlusal relationship, infection, nonunion, malunion, and plate dehiscence. We fixed 42 fractures with 43 resorbable plates; the fracture site of one patient (aged 11 years 3 months) was fixed with two plates. Two patients developed small fistulas at the intraoral incision 2 months after surgery; the fistulas healed after 1 month without special treatment. In the other patients, the incision healed well, there was facial symmetry, mouth opening was >35 mm, and occlusion was good. Follow-up computed tomography examination data were available for 20 cases, and revealed different degrees of radiolucency indicating that osteolysis had occurred. Radiolucency was observed around the resorbable plates 1 month after the surgery. The extent and depth of the radiolucent region were obvious within 1 year of surgery. In the second year, there were obvious repairs, with the bony defect areas becoming shallower. After 2 years, the bony defect areas had almost disappeared. Biodegradable fixation devices are safe and efficient for treating pediatric mandibular fractures. Osteolysis commonly follows biodegradable fixation of pediatric mandibular fractures, and has no adverse effect on fracture healing. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Tantalum(V) impurity extraction by octanol from niobium(V) fluoride solutions

International Nuclear Information System (INIS)

Majorov, V.G.; Nikolaev, A.I.; Kopkov, V.K.

2002-01-01

The conditions of the niobium and tantalum extraction separation by octanol in the fluoride solutions, depending on the metals and free hydrofluoric acid concentration as well as on the organic and water phases voluminous relation, are studied for the purpose of developing the technology of niobium deep purification from the tantalum impurities. The technological scheme of the niobium solutions(V) extraction purification from the tantalum impurities(V), which provides for obtaining the niobium oxide(V), containing less than 0.005 mass % Ta 2 O 5 , is proposed on the basis of the established optimal separation conditions. The possibility of using the developed technology by the pyrochlore reprocessing is indicated [ru

Behaviour of tantalum- and ceramics implants in the organism

International Nuclear Information System (INIS)

Reich, M.

1987-01-01

Studies of human and animal tissues after the use of orthopaedic implants were carried out by means of instrumental neutron activation analysis (INAA), as well as studies on the corrosion behaviour of tantalum by means of tracer techniques. After the use of an Al 2 O 3 -ceramic-metal compound prosthesis of the hip joint samples from the joint capsule and the Fascia Lata of 9 patients were studied. The measured Al amounts in the capsule tissues were greater than the normal values by up to 3 orders of magnitude. The corrosion experiment with tantalum was carried out in Ringer's solution as a model of body fluids. Local and systemic changes because of tantalum implants in animal experiments showed massive local stress of the contact tissue as a result of corrosion. Along with this, increased values of Ta were found in the spleen and the liver. (orig./RB) [de

Carbon monoxide and carbon dioxide interaction with tantalum

International Nuclear Information System (INIS)

Belov, V.D.; Ustinov, Yu.K.; Komar, A.P.

1978-01-01

The adsorption of carbon monoxide and carbon dioxide on tantalum and the dissolution of these gases in the adsorbent at T >= 300 K have been studied. The flash-filament method (FFM) in a monopole mass-spectrometer and a field emission microscopy was used in the same apparatus. Carbon monoxide and carbon dioxide dissociate on the tantalum surface, carbon monoxide being desorbed in both cases during the flash. The desorption curves of CO reveal three different binding states: two of them (α and β' 1 ) for the adsorbed particles whereas the high temperature desorption state relates to the adsorbate dissolved in the metal. For the β' 1 state of CO the activation energy, the pre-exponential factor and the kinetic order in the kinetic equation of desorption have been estimated. They turned out to be E = 110 kcal/mol, C = 3 X 10 12 sec -1 , and γ = 1. The activation energy of diffusion for CO in tantalum and the energy of outgassing for the metal were found to be 9.4 and 49 kcal/mole, respectively. (Auth.)

Carbon monoxide and carbon dioxide interaction with tantalum

Energy Technology Data Exchange (ETDEWEB)

Belov, V D; USTINOV, YU K; KOMAR, A P [AN SSSR, LENINGRAD. FIZIKO-TEKHNICHESKIJ INST.

1978-03-01

The adsorption of carbon monoxide and carbon dioxide on tantalum and the dissolution of these gases in the adsorbent at T >= 300 K have been studied. The flash-filament method (FFM) in a monopole mass-spectrometer and a field emission microscopy was used in the same apparatus. Carbon monoxide and carbon dioxide dissociate on the tantalum surface, carbon monoxide being desorbed in both cases during the flash. The desorption curves of CO reveal three different binding states: two of them (..cap alpha.. and ..beta..'/sub 1/) for the adsorbed particles whereas the high temperature desorption state relates to the adsorbate dissolved in the metal. For the ..beta..'/sub 1/ state of CO the activation energy, the pre-exponential factor and the kinetic order in the kinetic equation of desorption have been estimated. They turned out to be E = 110 kcal/mol, C = 3 X 10/sup 12/ sec/sup -1/, and ..gamma.. = 1. The activation energy of diffusion for CO in tantalum and the energy of outgassing for the metal were found to be 9.4 and 49 kcal/mole, respectively.

Niobium and tantalum

International Nuclear Information System (INIS)

Polupanova, L.I.; Volkova, G.A.

1983-01-01

General mineralogical-geochemical and analytical characteristics of niobium and tantalum are presented. Potentialities of any analytical methods for determining these elements in various geologic samples are estimated. The following specific techniques are described: neutron + activation determination of Ta, fluorescence X-radiometric determination of Nb and Ta, fluorescence X-ray spectral determination of Nb and Ta, spectrographic determination of Nb and Ta, gravimetric determination of Nb and Ta, their extraction-photometric determination with various reagents (crystal violet, rhodamine 6 Y, butylrhodamine B)

Non-invasive head fixation for external irradiation of tumors of the head and neck

International Nuclear Information System (INIS)

Bale, R.J.; Sweeney, R.; Nevinny, M.; Auer, T.; Bluhm, A.; Lukas, P.; Vogele, M.; Thumfart, W.F.

1998-01-01

Purpose: To fully utilize the technical capabilities of radiation diagnostics and planning, a precise and reproducible method of head fixation is a prerequisite. Method: We have adapted the Vogele-Bale-Hohner (VBH) head holder (Wellhoefer Dosimetrie, Schwarzenbruck, Germany), originally designed for frameless stereotactic operations, to the requirements of external beam radiotherapy. A precise and reproducible head fixation is attained by an individualized vacuum upper-dental cast which is connected over 2 hydraulic arms to an adjustable head- and rigid base-plate. Radiation field and patient alignment lasers are marked on a relocatable clear PVC localization box. Results: The possibility of craniocaudal adjustment of the head plate on the base plate allows the system to adapt to the actucal position of the patient on the raditherapy couch granting tensionless repositioning. The VBH head holder has proven itself to be a precise yet practicable method of head fixation. Duration of mouthpiece production and daily repositioning is comparable to that of the thermoplastic mask. Conclusion: The new head holder is in routine use at our hospital and quite suitable for external beam radiation of patients with tumors of the head and neck. (orig.) [de

Variability in dynamic properties of tantalum : spall, attenuation and load/unload.

Energy Technology Data Exchange (ETDEWEB)

Furnish, Michael David; Reinhart, William Dodd; Trott, Wayne Merle; Vogler, Tracy John; Chhabildas, Lalit Chandra

2005-07-01

A suite of impact experiments was conducted to assess spatial and shot-to-shot variability in dynamic properties of tantalum. Samples had a uniform refined {approx}20 micron grain structure with a strong axisymmetric [111] crystallographic texture. Two experiments performed with sapphire windows (stresses of approximately 7 and 12 GPa) clearly showed elastic-plastic loading and slightly hysteretic unloading behavior. An HEL amplitude of 2.8 GPa (corresponding to Y 1.5 GPa) was observed. Free-surface spall experiments showed clear wave attenuation and spallation phenomena. Here, loading stresses were {approx} 12.5 GPa and various ratios of impactor to target thicknesses were used. Spatial and shot-to-shot variability of the spall strength was {+-} 20%, and of the HEL, {+-} 10%. Experiments conducted with smaller diameter flyer plates clearly showed edge effects in the line and point VISAR records, indicating lateral release speeds of roughly 5 km/s.

Microstructures and phase transformations in interstitial alloys of tantalum

International Nuclear Information System (INIS)

Dahmen, U.

1979-01-01

The analysis of microstructures, phases, and possible ordering of interstitial solute atoms is fundamental to an understanding of the properties of metal-interstitial alloys in general. As evidenced by the controversies on phase transformations in the particular system tantalum--carbon, our understanding of this class of alloys is inferior to our knowledge of substitutional metal alloys. An experimental clarification of these controversies in tantalum was made. Using advanced techniques of electron microscopy and ultrahigh vacuum techology, an understanding of the microstructures and phase transformations in dilute interstitial tantalum--carbon alloys is developed. Through a number of control experiments, the role and sources of interstitial contamination in the alloy preparation (and under operating conditions) are revealed. It is demonstrated that all previously published work on the dilute interstitially ordered phase Ta 64 C can be explained consistently in terms of ordering of the interstitial contaminants oxygen and hydrogen, leading to the formation of the phases Ta 12 O and Ta 2 H

Structural characterisation of oxygen diffusion hardened alpha-tantalum PVD-coatings on titanium.

Science.gov (United States)

Hertl, C; Koll, L; Schmitz, T; Werner, E; Gbureck, U

2014-08-01

Titanium substrates were coated with tantalum layers of 5 μm thickness using physical vapour deposition (PVD). The tantalum layers showed a (110)-preferred orientation. The coated samples were hardened by oxygen diffusion. Using X-ray diffraction the crystallographic structure of the tantalum coatings was characterised, comparing untreated and diffusion hardened specimen conditions. Oxygen depth profiles were determined by glow discharge spectrometry. The hardening effect of the heat treatment was examined by Vickers microhardness testing. The increase of surface hardness caused by oxygen diffusion was at least 50%. Copyright © 2014 Elsevier B.V. All rights reserved.

Biological Response of Human Bone Marrow-Derived Mesenchymal Stem Cells to Commercial Tantalum Coatings with Microscale and Nanoscale Surface Topographies

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Skoog, Shelby A.; Kumar, Girish; Goering, Peter L.; Williams, Brian; Stiglich, Jack; Narayan, Roger J.

2016-06-01

Tantalum is a promising orthopaedic implant coating material due to its robust mechanical properties, corrosion resistance, and excellent biocompatibility. Previous studies have demonstrated improved biocompatibility and tissue integration of surface-treated tantalum coatings compared to untreated tantalum. Surface modification of tantalum coatings with biologically inspired microscale and nanoscale features may be used to evoke optimal tissue responses. The goal of this study was to evaluate commercial tantalum coatings with nanoscale, sub-microscale, and microscale surface topographies for orthopaedic and dental applications using human bone marrow-derived mesenchymal stem cells (hBMSCs). Tantalum coatings with different microscale and nanoscale surface topographies were fabricated using a diffusion process or chemical vapor deposition. Biological evaluation of the tantalum coatings using hBMSCs showed that tantalum coatings promote cellular adhesion and growth. Furthermore, hBMSC adhesion to the tantalum coatings was dependent on surface feature characteristics, with enhanced cell adhesion on sub-micrometer- and micrometer-sized surface topographies compared to hybrid nano-/microstructures. Nanostructured and microstructured tantalum coatings should be further evaluated to optimize the surface coating features to promote osteogenesis and enhance osseointegration of tantalum-based orthopaedic implants.

The evaluation of hydroxyapatite (HA) coated and uncoated porous tantalum for biomedical material applications

International Nuclear Information System (INIS)

Safuan, Nadia; Sukmana, Irza; Kadir, Mohammed Rafiq Abdul; Noviana, Deni

2014-01-01

Porous tantalum has been used as an orthopedic implant for bone defects as it has a good corrosion resistance and fatigue behaviour properties. However, there are some reports on the rejection of porous Ta after the implantation. Those clinical cases refer to the less bioactivity of metallic-based materials. This study aims to evaluate hydroxyapatite coated and uncoated porous Tantalum in order to improve the biocompatibility of porous tantalum implant and osseointegration. Porous tantalum was used as metallic-base substrate and hydroxyapatite coating has been done using plasma-spraying technique. Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM) techniques were utilizes to investigate the coating characteristics while Confocal Raman Microscopy to investigate the interface and image. The effect of coating to the corrosion behaviour was assessed by employing potentiodynamic polarization tests in simulated body fluid at 37±1 °C. Based on SEM and FESEM results, the morphologies as well the weight element consists in the uncoated and hydroxyapatite coated porous tantalum were revealed. The results indicated that the decrease in corrosion current density for HA coated porous Ta compared to the uncoated porous Ta. This study concluded that by coating porous tantalum with HA supports to decrease the corrosion rate of pure porous.

The Evaluation of Hydroxyapatite (HA) Coated and Uncoated Porous Tantalum for Biomedical Material Applications

Science.gov (United States)

Safuan, Nadia; Sukmana, Irza; Kadir, Mohammed Rafiq Abdul; Noviana, Deni

2014-04-01

Porous tantalum has been used as an orthopedic implant for bone defects as it has a good corrosion resistance and fatigue behaviour properties. However, there are some reports on the rejection of porous Ta after the implantation. Those clinical cases refer to the less bioactivity of metallic-based materials. This study aims to evaluate hydroxyapatite coated and uncoated porous Tantalum in order to improve the biocompatibility of porous tantalum implant and osseointegration. Porous tantalum was used as metallic-base substrate and hydroxyapatite coating has been done using plasma-spraying technique. Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM) techniques were utilizes to investigate the coating characteristics while Confocal Raman Microscopy to investigate the interface and image. The effect of coating to the corrosion behaviour was assessed by employing potentiodynamic polarization tests in simulated body fluid at 37±1 °C. Based on SEM and FESEM results, the morphologies as well the weight element consists in the uncoated and hydroxyapatite coated porous tantalum were revealed. The results indicated that the decrease in corrosion current density for HA coated porous Ta compared to the uncoated porous Ta. This study concluded that by coating porous tantalum with HA supports to decrease the corrosion rate of pure porous.

Evaluation of residual stress in sputtered tantalum thin-film

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Al-masha’al, Asa’ad, E-mail: asaad.al@ed.ac.uk; Bunting, Andrew; Cheung, Rebecca

2016-05-15

Highlights: • Tantalum thin-films have been deposited by DC magnetron sputtering system. • Thin-film stress is observed to be strongly influenced by sputtering pressure. • Transition towards the compressive stress is ascribed to the annealing at 300 °C. • Expose thin-film to air ambient or ion bombardment lead to a noticeable change in the residual stress. - Abstract: The influence of deposition conditions on the residual stress of sputtered tantalum thin-film has been evaluated in the present study. Films have been deposited by DC magnetron sputtering and curvature measurement method has been employed to calculate the residual stress of the films. Transitions of tantalum film stress from compressive to tensile state have been observed as the sputtering pressure increases. Also, the effect of annealing process at temperature range of 90–300 °C in oxygen ambient on the residual stress of the films has been studied. The results demonstrate that the residual stress of the films that have been deposited at lower sputtering pressure has become more compressive when annealed at 300 °C. Furthermore, the impact of exposure to atmospheric ambient on the tantalum film stress has been investigated by monitoring the variation of the residual stress of both annealed and unannealed films over time. The as-deposited films have been exposed to pure Argon energy bombardment and as result, a high compressive stress has been developed in the films.

Valgus osteotomy of the tibia with a Puddu plate combined with anterior cruciate ligament reconstruction

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Albuquerque Roberto Freire da Mota e

2003-01-01

Full Text Available Anterior knee instability associated with a varus deformity is a complex condition with several treatment possibilities. Among these, anterior cruciate ligament (ACL associated to a simultaneous valgus tibial osteotomy is a increasing indication. This simultaneous procedure adds technical issues to those related to the isolated surgeries. Thus, the osteotomy plane and location of fixation hardware shouldn?t conflict with tibial tunnel and ACL graft fixation. Authors analyze the relations between a opening tibial valgus osteotomy stabilized with a Puddu plate and ACL reconstruction with a patellar tendon graft fixated with interference screws in 10 human cadaver knees. A straight oblique tibial osteotomy starting on the medial tibial cortex and oriented laterally and proximally was performed on all knees with a 10mm opening medially and stabilized with a Puddu plate on the most posterior aspect of the medial tibia, and a tibial tunnel drilled 50° to tibial plateau. With this technique there was no intersection between tibial tunnel or interference screw and the osteotomy or the plate fixation screws.

The clinical application of absorbable intramedullary nail and claw plate on treating multiple rib fractures.

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Chai, X; Lin, Q; Ruan, Z; Zheng, J; Zhou, J; Zhang, J

2013-08-01

The absorption intramedullary nail and claw plate indications and efficacy were investigated in the treatment of a life-threatening multiple rib fractures. A retrospective analysis of 248 surgically treated rib fracture patients was performed who admitted to our hospital from March 2007 to December 2012. Intramedullary nailing was performed in 28 cases, a claw-type bone plate was fixed in 141 cases, and a combination of both was fixed in 79 cases. All internal fixation patients were clinically cured except 1 patient died 14 days after a massive pulmonary embolism. The patients with flail chest and floating chest wall causing respiratory and circulatory disorders were promptly corrected. Routine follow-up was from 1 to 2 years, displaced fractures were in 2 cases, and there were 11 cases of internal fixation and extraction. Internal fixation is a simple and reliable method for the treatment of multiple rib fractures. Both internal fixation materials have their pros and cons but the claw bone plate is more robust. The actual selection of appropriate treatment options helps to improve the treatment efficacy.

Mid-term functional outcome after the internal fixation of distal radius fractures

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Phadnis Joideep

2012-01-01

Full Text Available Abstract Background Distal radius fracture is a common injury with a variety of operative and non-operative management options. There remains debate as to the optimal treatment for a given patient and fracture. Despite the popularity of volar locking plate fixation, there are few large cohort or long term follow up studies to justify this modality. Our aim was to report the functional outcome of a large number of patients at a significant follow up time after fixation of their distal radius with a volar locking plate. Methods 180 patients with 183 fractures and a mean age of 62.4 years were followed up retrospectively at a mean of 30 months (Standard deviation = 10.4. Functional assessment was performed using the Disabilities of the Arm, Shoulder and Hand (DASH and modified MAYO wrist scores. Statistical analysis was performed to identify possible variables affecting outcome and radiographs were assessed to determine time to fracture union. Results The median DASH score was 2.3 and median MAYO score was 90 for the whole group. Overall, 133 patients (74% had a good or excellent DASH and MAYO score. Statistical analysis showed that no specific variable including gender, age, fracture type, post-operative immobilisation or surgeon grade significantly affected outcome. Complications occurred in 27 patients (15% and in 11 patients were major (6%. Conclusion This single centre large population series demonstrates good to excellent results in the majority of patients after volar locking plate fixation of the distal radius, with complication rates comparable to other non-operative and operative treatment modalities. On this basis we recommend this mode of fixation for distal radius fractures requiting operative intervention.

Tantalum oxide-based compounds as new non-noble cathodes for polymer electrolyte fuel cell

International Nuclear Information System (INIS)

Ishihara, Akimitsu; Tamura, Motoko; Matsuzawa, Koichi; Mitsushima, Shigenori; Ota, Ken-ichiro

2010-01-01

Tantalum oxide-based compounds were examined as new non-noble cathodes for polymer electrolyte fuel cell. Tantalum carbonitride powder was partially oxidized under a trace amount of oxygen gas at 900 o C for 4 or 8 h. Onset potential for oxygen reduction reaction (ORR) of the specimen heat-treated for 8 h was 0.94 V vs. reversible hydrogen electrode in 0.1 mol dm -3 sulfuric acid at 30 o C. The partial oxidation of tantalum carboniride was effective to enhance the catalytic activity for the ORR. The partially oxidized specimen with highest catalytic activity had ca. 5.25 eV of ionization potential, indicating that there was most suitable strength of the interaction of oxygen and tantalum on the catalyst surface.

Aspects of internal fixation of fractures in porotic bone. Principles, technologies and procedures using locked plate screws.

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Perren, S M; Linke, B; Schwieger, K; Wahl, D; Schneider, E

2005-01-01

Fractures of the bones of elderly people occur more often and have a more important effect because of a generally diminished ability to coordinate stance and walking. These fractures occur at a lower level of load because of lack of strength of the porotic bone. Prompt recovery of skeletal support function is essential to avoid respiratory and circulatory complications in the elderly. To prevent elderly people from the risks of being bedridden, demanding internal fixation of fractures is required. The weak porotic bone and the high level of uncontrolled loading after internal fixation pose complex problems. A combination of several technical elements of design, application and aftercare in internal fixation are proposed. Internal fixators with locked screws improve the biology and the mechanics of internal fixation. When such fixators are used as elevated splints they may stimulate early callus formation because of their flexibility, the limit of flexibility being set by the demands of resistance and function of the limb. Our own studies of triangulation of locked screws have demonstrated their beneficial effects and unexpected limitations.

A study for an electrolytic reduction of tantalum oxide in a LiCl-Li2O molten salt

International Nuclear Information System (INIS)

Park, Sung Bin; Park, Byung Heung; Seo, Chung Seok; Kang, Dae Seung; Kwon, Seon Gil; Park, Seong Won

2005-01-01

Korea Atomic Energy Research Institute (KAERI) has developed the Advanced Spent Fuel Conditioning Process (ACP) to be an innovative technology for handling the PWR spent fuel. As part of ACP, the electrolytic reduction process (ER process) is the electrochemical reduction process of uranium oxide to uranium metal in a molten salt. The ER process has advantages in a technical stability, an economic potential and a good proliferation resistance. KAERI has reported on the good experimental results of an electrochemical reduction of the uranium oxide in a 20 kg HM/batch lab-scale. The ER process can be applicable to the reduction of other metal oxides. Metal tantalum powder has attracted attention for a variety of applications. A tantalum capacitor made from superfine and pliable tantalum powders is very small in size and it has a higher-capacitance part, therefore it is useful for microelectronic devices. By the ER process the metal tantalum can be obtained from tantalum pentoxide. In this work, a 40 g Ta 2 O 5 /batch electrochemical reactor was used for the synthesis of the metal tantalum. From the results of the cyclic voltammograms for the Ta 2 O 5 -LiCl-Li 2 O system, the mechanism of the tantalum reduction in a molten LiCl-Li 2 O salt system was investigated. Tantalum pentoxide is chemically reduced to tantalum metal by the lithium metal which is electrochemically deposited into an integrated cathode assembly in the LiCl-Li 2 O molten salt. The experiments for the tantalum reduction were performed with a chronopotentiometry in the reactor cell, the reduced products were analyzed from an analysis of the X-ray diffraction (XRD), scanning electron microscope and energy dispersive X-ray (SEM-EDX). From the results, the electrolytic reduction process is applicable to the synthesis of metal tantalum

Finite element analysis of the three different posterior malleolus fixation strategies in relation to different fracture sizes.

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Anwar, Adeel; Lv, Decheng; Zhao, Zhi; Zhang, Zhen; Lu, Ming; Nazir, Muhammad Umar; Qasim, Wasim

2017-04-01

Appropriate fixation method for the posterior malleolar fractures (PMF) according to the fracture size is still not clear. Aim of this study was to evaluate the outcomes of the different fixation methods used for fixation of PMF by finite element analysis (FEA) and to compare the effect of fixation constructs on the size of the fracture computationally. Three dimensional model of the tibia was reconstructed from computed tomography (CT) images. PMF of 30%, 40% and 50% fragment sizes were simulated through computational processing. Two antero-posterior (AP) lag screws, two postero-anterior (PA) lag screws and posterior buttress plate were analysed for three different fracture volumes. The simulated loads of 350N and 700N were applied to the proximal tibial end. Models were fixed distally in all degrees of freedom. In single limb standing condition, the posterior plate group produced the lowest relative displacement (RD) among all the groups (0.01, 0.03 and 0.06mm). Further nodal analysis of the highest RD fracture group showed a higher mean displacement of 4.77mm and 4.23mm in AP and PA lag screws model (p=0.000). The amounts of stress subjected to these implants, 134.36MPa and 140.75MPa were also significantly lower (p=0.000). There was a negative correlation (p=0.021) between implant stress and the displacement which signifies a less stable fixation using AP and PA lag screws. Progressively increasing fracture size demands more stable fixation construct because RD increases significantly. Posterior buttress plate produces superior stability and lowest RD in PMF models irrespective of the fragment size. Copyright © 2017 Elsevier Ltd. All rights reserved.

Advantages of external hybrid fixators for treating Schatzker V-VI tibial plateau fractures: A retrospective study of 40 cases.

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Gross, J-B; Gavanier, B; Belleville, R; Coudane, H; Mainard, D

2017-10-01

Proximal tibia fractures make up 1% of all fractures in adults. The fractures classified as Schatzker V and VI fractures can compromise knee structure and function. They are challenging to treat and often have complications. While plate fixation is the gold standard, the resulting infection rate has led us to favor external hybrid fixation. The aims of this study were to assess the radiographic and functional outcomes along with the complication rate when using this method and to compare them to historical plate fixation data. This was a retrospective study of 40 patients. The complications, quality of reduction, IKS, Lysholm and Rasmussen functional scores at the latest follow-up and factors affecting the functional outcome were evaluated. These parameters were compared to published results from plate fixation studies. The deep infection rate was 2.5%. The union rate was 80%. Satisfactory reduction was obtained in 70% of cases; however, 52% of patients had malunion. The mean IKS score was 73.74, the mean Rasmussen score was 22.85 and the mean Lysholm score was 75.53. Age, reduction at latest follow-up, mechanical axis and anteroposterior laxity had a significant effect on the functional outcome. Despite the malunion rate being higher than other studies, the functional outcomes were nearly identical based on the variables measured. There are several advantages associated with using a hybrid external fixator: shorter operative time, less bleeding, shorter hospital stays and lower infection rate. Hybrid external fixation is a reliable fracture fixation method that leads to satisfactory functional outcomes, while reducing the infection rate and allowing arthroplasty to be performed in the future if needed. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Rate of Improvement following Volar Plate Open Reduction and Internal Fixation of Distal Radius Fractures

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Chris Dillingham

2011-01-01

Full Text Available Purpose. To determine recovery timeline of unstable distal radius fractures treated by open reduction and internal fixation with a locking volar plate. Methods. Data was collected prospectively on a consecutive series of twenty-seven patients during routine post-operative visits at 2 and 6 weeks, and 3, 6, 12 and 24 months. Range of motion measures and grip strength for both wrists were recorded. Results. Greatest gains were made within the first 3 months after surgery. Supination and pronation returned more quickly than flexion or extension, with supination and pronation both at 92% of the uninjured wrist at 3 months. Only flexion improved significantly between 3 and 6 months. All wrist motions showed some improvement until 1 year. Grip strength returned to 94% of the uninjured wrist by 12 months. Conclusions. Range of motion improvement will be greatest between 2 weeks and 3 months, with improvement continuing until 12 months. Grip strength should return to near normal by one year. Function and pain will improve, but not return to normal by the end of 12 months. Clinical Relevance. These results provide the surgeon with information that can be shared with patients on the anticipated timeline for normal recovery of function and strength.

Recent advances in P/M-tantalum products

International Nuclear Information System (INIS)

Kumar, P.; Uhlenhut, H.

2001-01-01

The metallurgical grade tantalum powder is used for producing parts and mill products. Some of the key requirements include purity, physical characteristics (flow, fill density and compressibility) and interstitial contents. A process to produce 99.99 % pure tantalum powder with less than 150 ppm oxygen has been developed. This powder was consolidated into metallurgical products via conventional P/M processing; resulting products had high purity and low oxygen. It also retained fine grain-size and uniform properties inherent in P/M-derived products. In addition, the desired crystallographic texture was obtained by controlled thermo-mechanical processing (TMP) of the consolidated powder. Fully dense products of this powder were tested for various applications, such as deep drawing, sputtering, ballistics and capacitors. Critical functional requirements in these applications along with the results of evaluations are discussed. (author)

Tantalum and niobium carbides obtention by carbothermic reduction of columbotantalite ores

International Nuclear Information System (INIS)

Gordo, E.; Garcia-Carcedo, F.; Torralba, J.M.

1998-01-01

Tantalum and niobium carbides are characterized by its high hardness and chemical corrosion resistance. Both carbides, but mainly TaC, are used in hard metals (sintered carbides), together with their carbides, to manufacture cutting tools and dies in special machining applications involving mechanical shock at high temperature. Its use as reinforcement of wear resistant materials through powder metallurgy techniques are being investigated. However, the use of TaC is usually limited because of its high cost. Therefore tantalum carbide with niobium content, which is cheaper, is used. In this work the obtention of complex tantalum and niobium carbides from a Spanish columbotantalite ore is studied through relatively cheap and simple process as it is carbothermic reduction. Concentration of the ore, its reduction and the characterization of products are described. (Author) 11 refs

Operative Fixation of Rib Fractures Indications, Techniques, and Outcomes.

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Galos, David; Taylor, Benjamin; McLaurin, Toni

2017-01-01

Rib fractures are extremely common injuries and vary in there severity from single nondisplaced fractures to multiple segmental fractures resulting in flail chest and respiratory compromise. Historically, rib fractures have been treated conservatively with pain control and respiratory therapy. However this method may not be the best treatment modality in all situations. Operative fixation of select rib fractures has been increasing in popularity especially in patients with flail chest and respiratory compromise. Newer techniques use muscle sparing approaches and precontoured locking plate technology to obtain stable fixation and allow improved respiration. Current reports shows that rib fracture fixation offers the benefits of improved respiratory mechanics and improved pain control in the severe chest wall injury with resultant improvement in patient outcomes by decreasing time on the ventilator, time in the intensive care unit, and overall hospital length of stay.

Unconventional fixation Thoracolumbar fractures using round hole boneplates and transpedicular screws

International Nuclear Information System (INIS)

Behairy, Yaser M.

2001-01-01

In an attempt to contain the high cost of commercially available pediclescrew systems, several authors have used unconventional alternatives such aslocally made plates or dynamic compression plates (DCP) along with cancellousscrews for transpedicular fixation of the thoracolumbar spine. These plates,however, allow for a wide range of motion at the plate-screw interphase andthe construct does not provide stability in the sagittal plane. Round holebone plates, on the other hand, allow much less mobility at the plate-screwinterphase and the final construct offers better stability in the sagittalplane. Our objective was to determine the clinical, radiologic and functionalstatus of patients who underwent posterior fracture fixation using round holebone plates and cancellous screws and evaluate the construct's ability tomaintain reduction of the fracture. This was a postoperative follow-up ofpatients with fractures around the thoracolumbar junction fixed using roundhole bone plates and cancellous transpedicular screws. Round hole bone platesalong with 6.5 mm transpedicular cancellous screws were used for posteriorspinal instrumentation in neurologically intact patients with isolatedunstable fractures of the last thoracic or first lumbar vertebra. Seventeenpatients were included in this study. There mean follow-up was 10 months(range 5 to 12). All had evidence of fusion at a mean of 5 months (range 4 to7). No patients had breakage or loosening of the screws and none had breakageof the plate. The mean kyphosis angle at the fracture site was 34 degreepreoperatively, -4 degree in the immediate postoperative period, and 3 degreeon final follow-up radiographs. The percentage loss of anterior vertebralbody height was 51% in the immediate postoperative period and 16% on finalfollow-up radiographs. The use of round hole bone plates along with 6.5 mmcancellous screws inserted into the pedicles provides an angle-stableconstruct that allows for better stability in the sagittal plane

Comparative study of tantalum deposition by chemical vapor deposition and electron beam vacuum evaporation

International Nuclear Information System (INIS)

Spitz, J.; Chevallier, J.

1975-01-01

The coating by tantalum of steel parts has been carried out by the two following methods: chemical vapor deposition by hydrogen reduction of TaCl 5 (temperature=1100 deg C, pressure=200 mmHg, H 2 /TaCl 5 =10); electron beam vacuum evaporation. In this case Ta was firstly condensed by ion plating (P(Ar)=5x10 -3 up to 2x10 -2 mmHg; U(c)=3 to -4kV and J(c)=0.2 to 1mAcm -2 ) in order to ensure a good adhesion between deposit and substrate; then by vacuum condensation (substrate temperature: 300 to 650 deg C) to ensure that the coating is impervious to HCl an H 2 SO 4 acids. The advantages and inconveniences of each method are discussed [fr

Radiographic Outcomes of Dorsal Distraction Distal Radius Plating for Fractures With Dorsal Marginal Impaction.

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Huish, Eric G; Coury, John G; Ibrahim, Mohamed A; Trzeciak, Marc A

2017-04-01

The purpose of this study is to compare radiographic outcomes of patients treated with dorsal spanning plates with previously reported normal values of radiographic distal radius anatomy and compare the results with prior publications for both external fixation and internal fixation with volar locked plates. Patients with complex distal radius fractures including dorsal marginal impaction pattern necessitating dorsal distraction plating at the discretion of the senior authors (M.A.T. and M.A.I.) from May 30, 2013, to December 29, 2015, were identified and included in the study. Retrospective chart and radiograph review was performed on 19 patients, 11 male and 8 female, with mean age of 47.83 years (22-82). No patients were excluded from the study. All fractures united prior to plate removal. The average time the plate was in place was 80.5 days (49-129). Follow-up radiographs showed average radial inclination of 20.5° (13.2°-25.5°), radial height of 10.7 mm (7.5-14 mm), ulnar variance of -0.3 mm (-2.1 to 3.1 mm), and volar tilt of 7.9° (-3° to 15°). One patient had intra-articular step-off greater than 2 mm. Dorsal distraction plating of complex distal radius fractures yields good radiographic results with minimal complications. In cases of complex distal radius fractures including dorsal marginal impaction where volar plating is not considered adequate, a dorsal distraction plate should be considered as an alternative to external fixation due to reduced risk for infection and better control of volar tilt.

Osteosynthesis of the diaphysis of the humeral with plates - Series of cases

International Nuclear Information System (INIS)

Reyes Reyes, Claudia Juliana; Valencia Chamorro, Martha Patricia; Garcia Gonzalez, Luis Alejandro

2005-01-01

Humeral shaft fractures may be treated in various ways. When surgical treatment is preferred, both plates and intramedullary nails are available and feasible options; the latter have recently gained popularity. We present the results of a case series of humeral fractures treated by open reduction and plate fixation with DCP plates, the results are described in terms of union rate, function, satisfaction, and complications. Thirty patients were included, with ages from 18 to 74 years, with mean follow-up time of 35 months; twelve patients were treated for delayed or non-union after orthopedic treatment. There was one case of nonunion, and one of iatrogenic neurapraxia of the radial nerve. Mobility and strength were excellent. All patients reported to be satisfied with the treatment and its result. We discuss that plate fixation for humeral shaft fractures is a predictable choice, with low complication rate and high union rate

An alternative method in mandibular fracture treatment: bone graft use instead of a plate.

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Alagöz, Murat Sahin; Uysal, Ahmet Cagri; Sensoz, Omer

2008-03-01

In the treatment of the mandibular fractures, one of the main principles is to use the least amount of foreign material. We present an alternative technique that the bone grafts harvested from the fracture borders or from the iliac crest were used instead of plates and the fixation was done with screws. In the study including 24 mandible fractures, the bone grafts harvested from the fracture borders were used in the 10 favorable fractures and the bone grafts harvested from the iliac crest were used in the 14 unfavorable fractures. In the combined mandible fractures, four fractures were fixated with titanium plates and the other side with the bone graft. The patients, who were followed up for 12 to 20 months, were evaluated with macroscopic occlusion, panoramic graphs, and three-dimensional computerized tomographs. The advantage of this technique of fixation with the autogenous tissue is reduced infection rates and reduced operation costs. In the pediatric patients, the second session operation of plate removal is not necessary.

Dorsal bridge plating or transarticular screws for Lisfranc fracture dislocations.

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Kirzner, N; Zotov, P; Goldbloom, D; Curry, H; Bedi, H

2018-04-01

Aims The aim of this retrospective study was to compare the functional and radiological outcomes of bridge plating, screw fixation, and a combination of both methods for the treatment of Lisfranc fracture dislocations. Patients and Methods A total of 108 patients were treated for a Lisfranc fracture dislocation over a period of nine years. Of these, 38 underwent transarticular screw fixation, 45 dorsal bridge plating, and 25 a combination technique. Injuries were assessed preoperatively according to the Myerson classification system. The outcome measures included the American Orthopaedic Foot and Ankle Society (AOFAS) score, the validated Manchester Oxford Foot Questionnaire (MOXFQ) functional tool, and the radiological Wilppula classification of anatomical reduction. Results Significantly better functional outcomes were seen in the bridge plate group. These patients had a mean AOFAS score of 82.5 points, compared with 71.0 for the screw group and 63.3 for the combination group (p bridge plate group, 38.1 in the screw group, and 45.5 in the combination group (p bridge plating have better functional and radiological outcomes than those treated with transarticular screws or a combination technique. Cite this article: Bone Joint J 2018;100-B:468-74.

SURGICAL MANAGEMENT OF TRAUMATIC MANUBRIO-STERNAL DISLOCATION WITH LOCKING COMPRESSION PLATE; A CASE REPORT AND REVIEW OF LITERATURE

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FAREED AHMED SHAIKH

2017-05-01

Full Text Available Background: Manubriosternal joint dislocation as a result of trauma is rare with only few case reports published in literature. Materials that have been used for fixation of displaced manubriosternal joint are steel wires, polydioxanone ropes, and plates with screws. Case: We present a case of manubriosternal dislocation in which fixation was done with locking compression plate. This is a case of 32 years old lady with history of road traffic accident, car ran over her chest. She had bilateral lung contusions with multiple rib fractures on right side and manubriosternal joint dislocation of type-I. Patient was initially stabilized in high dependency unit, and once her contusions got better, she underwent fixation of her manubriosternal dislocation with locking compression plate. Post-operatively she remained pain free and was discharged home. Conclusion: This case is an important addition to literature regarding options that can be used for fixation of manubriosternal joint dislocation.

Micro/Nano Structural Tantalum Coating for Enhanced Osteogenic Differentiation of Human Bone Marrow Stem Cells.

Science.gov (United States)

Ding, Ding; Xie, Youtao; Li, Kai; Huang, Liping; Zheng, Xuebin

2018-04-03

Recently, tantalum has been attracting much attention for its anticorrosion resistance and biocompatibility, and it has been widely used in surface modification for implant applications. To improve its osteogenic differentiation of human bone marrow stem cells (hBMSCs), a micro/nano structure has been fabricated on the tantalum coating surface through the combination of anodic oxidation and plasma spraying method. The morphology, composition, and microstructure of the modified coating were comprehensively studied by employing scanning electron microscopy (SEM), X-ray diffraction (XRD) as well as transmission electron microscopy (TEM). The effects of hierarchical structures as well as micro-porous structure of tantalum coating on the behavior for human bone marrow stem cells (hBMSCs) were evaluated and compared at both cellular and molecular levels in vitro. The experimental results show that a hierarchical micro/nano structure with Ta₂O₅ nanotubes spread onto a micro-scale tantalum coating has been fabricated successfully, which is confirmed to promote cell adhesion and spreading. Besides, the hierarchical micro/nano tantalum coating can provide 1.5~2.1 times improvement in gene expression, compared with the micro-porous tantalum coating. It demonstrates that it can effectively enhance the proliferation and differentiation of hBMSCs in vitro.

Micro/Nano Structural Tantalum Coating for Enhanced Osteogenic Differentiation of Human Bone Marrow Stem Cells

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Ding Ding

2018-04-01

Full Text Available Recently, tantalum has been attracting much attention for its anticorrosion resistance and biocompatibility, and it has been widely used in surface modification for implant applications. To improve its osteogenic differentiation of human bone marrow stem cells (hBMSCs, a micro/nano structure has been fabricated on the tantalum coating surface through the combination of anodic oxidation and plasma spraying method. The morphology, composition, and microstructure of the modified coating were comprehensively studied by employing scanning electron microscopy (SEM, X-ray diffraction (XRD as well as transmission electron microscopy (TEM. The effects of hierarchical structures as well as micro-porous structure of tantalum coating on the behavior for human bone marrow stem cells (hBMSCs were evaluated and compared at both cellular and molecular levels in vitro. The experimental results show that a hierarchical micro/nano structure with Ta2O5 nanotubes spread onto a micro-scale tantalum coating has been fabricated successfully, which is confirmed to promote cell adhesion and spreading. Besides, the hierarchical micro/nano tantalum coating can provide 1.5~2.1 times improvement in gene expression, compared with the micro-porous tantalum coating. It demonstrates that it can effectively enhance the proliferation and differentiation of hBMSCs in vitro.

Random Vibration Testing of Advanced Wet Tantalum Capacitors

Science.gov (United States)

Teverovsky, Alexander

2015-01-01

Advanced wet tantalum capacitors allow for improved performance of power supply systems along with substantial reduction of size and weight of the systems that is especially beneficial for space electronics. Due to launch-related stresses, acceptance testing of all space systems includes random vibration test (RVT). However, many types of advanced wet tantalum capacitors cannot pass consistently RVT at conditions specified in MIL-PRF-39006, which impedes their use in space projects. This requires a closer look at the existing requirements, modes and mechanisms of failures, specifics of test conditions, and acceptance criteria. In this work, different lots of advanced wet tantalum capacitors from four manufacturers have been tested at step stress random vibration conditions while their currents were monitored before, during, and after the testing. It has been shown that the robustness of the parts and their reliability are mostly due to effective self-healing processes and limited current spiking or minor scintillations caused by RVT do not increase the risk of failures during operation. A simple model for scintillations events has been used to simulate current spiking during RVT and optimize test conditions. The significance of scintillations and possible effects of gas generation have been discussed and test acceptance criteria for limited current spiking have been suggested.

Superconducting properties and uniaxial strain characteristics of Nb3Sn fiber-reinforced superconductors with tantalum reinforcement fibers

International Nuclear Information System (INIS)

Arai, Kazuaki; Umeda, Masaichi; Agatsuma, Koh; Tateishi, Hiroshi

1998-01-01

We have been developing fiber-reinforced superconductors (FRS) for high-field and large-scale magnets. Tungsten fibers have been selected as the reinforcement fiber for FRS so far because tungsten has the highest elastic modulus of approximately 400 GPa which can minimize the strain from electromagnetic force. The preparation process of FRS consists of sputtering deposition and heat treatment because it may be difficult to apply drawing methods to materials of high-elastic modulus such as tungsten. Tantalum has high elastic modulus of 178 GPa and its thermal expansion coefficient that is closer to that of Nb 3 Sn than tungsten's, which means prestrain in Nb 3 Sn in FRS is reduced by adopting tantalum fibers. Tantalum has been used as barriers between bronze and copper in conventional Nb 3 Sn superconductors which are usually prepared with drawing process despite of the tantalum's high elastic modulus. That implies drawing process may be applied to prepare FRS with tantalum reinforcement fibers. In this paper, FRS using tantalum fibers prepared with sputtering process are described with making comparison with FRS of tungsten to clarify the basic properties of FRS using tantalum fibers. Depth profiles in Nb 3 Sn layer in FRS were measured to examine reaction between superconducting layers and reinforcement fibers. Superconducting properties including strain and stress characteristics were shown. Those data will contribute to design of FRS using tantalum reinforcement fibers with adopts the drawing processes. (author)

Sliding-screw plate fixation of proximal femoral fractures: Radiographic assessment

Energy Technology Data Exchange (ETDEWEB)

Sartoris, D.J.; Resnick, D.; Kerr, R.; Goergen, T.

1985-07-01

The sliding compression screw-sideplate combination is currently the most widely employed device for internal fixation of stable and unstable intertrochanteric fractures of the femur. The normal and abnormal radiographic appearances of this device in the immediate post-operative period are discussed. Potential long-term complications including mal- or non-union, intra-articular penetration, metal failure, rotation of the proximal fracture fragment, disengagement, trochanteric bursitis, leg length discrepancy, delayed cervical stress fracture, and ischemic necrosis are reviewed.

Sliding-screw plate fixation of proximal femoral fractures: Radiographic assessment

International Nuclear Information System (INIS)

Sartoris, D.J.; Resnick, D.; California Univ., San Diego, La Jolla; Kerr, R.; Goergen, T.

1985-01-01

The sliding compression screw-sideplate combination is currently the most widely employed device for internal fixation of stable and unstable intertrochanteric fractures of the femur. The normal and abnormal radiogrpahic appearances of this device in the immediate post-operative period are discussed. Potential long-term complications including mal- or non-union, intra-articular penetration, metal failure, rotation of the proximal fracture fragment, disengagement, trochanteric bursitis, leg length discrepancy, delayed cervical stress fracture, and ischemic necrosis are reviewed. (orig.)

Heat adaptation of bioabsorbable craniofacial plates: a critical review of science and technology.

Science.gov (United States)

Pietrzak, William S

2009-11-01

Bioabsorbable fixation plates often require adaptation to the bone. This is typically accomplished by heating the plates to above the glass transition temperature and placing the softened plates against the bone or a prebent template until cool. Upon cooling, the plates regain stiffness and can be attached to bone to obtain anatomic fixation. This procedure is both efficient and effective and has been used throughout the craniofacial skeleton. There are many types of equipment available to heat the plates, each with advantages and disadvantages. Although a conceptually simple process, there are several nuances that have been reported in the literature, including transient effects on plate mechanical properties, memory effects, differences between wet and dry heating, and others. Upon the backdrop of the overwhelming clinical success of heat adaptation, this review critically evaluates the method and provides a comprehensive examination and explanation of the basic science and technology involved. This should help give surgeons a better understanding of the process that can help improve their use and further advance the technology.

Electromigration of hydrogen and deuterium in vanadium, niobium, and tantalum

International Nuclear Information System (INIS)

Jensen, C.L.

1977-10-01

The electric mobility and effective valence of hydrogen and deuterium in vanadium, niobium, tantalum and three niobium-tantalum alloys were measured. A resistance technique was used to directly determine the electric mobility of hydrogen and deuterium at 30 0 C while a steady-state method was used to measure the effective valence. The use of mass spectrographic techniques on a single specimen which contained both hydrogen and deuterium greatly increased the precision with which the isotope effect in the effective valence could be measured

Comparison of the mechanical properties between tantalum and nickel-titanium foams implant materials for bone ingrowth applications

International Nuclear Information System (INIS)

Sevilla, P.; Aparicio, C.; Planell, J.A.; Gil, F.J.

2007-01-01

Metallic porous materials are designed to allow the ingrowth of living tissue inside the pores and to improve the mechanical anchorage of the implant. In the present work, tantalum and nickel-titanium porous materials have been characterized. The tantalum foams were produced by vapour chemical deposition (CVD/CVI) and the NiTi foams by self-propagating high temperature synthesis (SHS). The former exhibited an open porosity ranging between 65 and 73% and for the latter it ranged between 63 and 68%. The pore sizes were between 370 and 440 μm for tantalum and between 350 and 370 μm for nickel-titanium. The Young's modulus in compression of the foams studied, especially for tantalum, were very similar to those of cancellous bone. This similitude may be relevant in order to minimize the stress shielding effect in the load transfer from the implant to bone. The strength values for NiTi foam are higher than for tantalum, especially of the strain to fracture which is about 23% for NiTi and only 8% for tantalum. The fatigue endurance limit set at 10 8 cycles is about 7.5 MPa for NiTi and 13.2 MPa for tantalum. The failure mechanisms have been studied by scanning electron microscopy

OUTCOME OF LOCKING PLATES IN DISTAL TIBIA FRACTURES TREATMENT

OpenAIRE

Lokesh; Dayanand; Deepak; Hemanth

2016-01-01

INTRODUCTION Most of these fractures except intra-articular fractures are treated with interlocking nail. 1,2 These nails are a boon for these fractures. But as the fracture nears to the joint stability the fracture fixation will be compromised due to malreduction and alignment, it leads to increased chances of delayed and nonunion. 3 Locking anatomical plates are evaluated for anatomical and relative stability fixation. Since then most intra and near intra-articul...

Treatment of reducible unstable fractures of the distal radius: randomized clinical study comparing the locked volar plate and external fixator methods: study protocol.

Science.gov (United States)

Raduan Neto, Jorge; de Moraes, Vinicius Ynoe; Gomes Dos Santos, João B; Faloppa, Flávio; Belloti, João Carlos

2014-03-05

Various treatments are available for reducible unstable fractures of the distal radius, such as closed reduction combined with fixation by external fixator (EF), and rigid internal fixation using a locked volar plate (VP). Although there are studies comparing these methods, there is no conclusive evidence indicating which treatment is best. The hypothesis of this study is that surgical treatment with a VP is more effective than EF from the standpoint of functional outcome (patient-reported). The study is randomized clinical trial with parallel groups and a blinded evaluator and involves the surgical interventions EF and VP. Patients will be randomly assigned (assignment ratio 1:1) using sealed opaque envelopes. This trial will include consecutive adult patients with an acute (up to 15 days) displaced, unstable fracture of the distal end of the radius of type A2, A3, C1, C2 or C3 by the Arbeitsgemeinschaft für Osteosynthesefragen-Association for the Study of Internal Fixation classification and type II or type III by the IDEAL32 classification, without previous surgical treatments of the wrist. The surgical intervention assigned will be performed by three surgical specialists familiar with the techniques described. Evaluations will be performed at 2, and 8 weeks, 3, 6 and 12 months, with the primary outcomes being measured by the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and measurement of pain (Visual Analog Pain Scale and digital algometer). Secondary outcomes will include radiographic parameters, objective functional evaluation (goniometry and dynamometry), and the rate of complications and method failure according to the intention-to-treat principle. Final postoperative evaluations (6 and 12 months) will be performed by independent blinded evaluators. For the Student's t-test, a difference of 10 points in the DASH score, with a 95% confidence interval, a statistical power of 80%, and 20% sampling error results in 36 patients per group

Spectrochemical determination of tantalum in plutonium metal using direct current plasma emission spectrometry

International Nuclear Information System (INIS)

Fadeff, S.K.; Morris, W.F.

1983-01-01

Tantalum is determined by direct current plasma spectrometry after separation of plutonium from solution as PuF 3 . After centrifugation of the PuF 3 precipitate, a low level of plutonium remains in solution in sufficient quantity to cause spectral interferences. It is necessary to determine the plutonium by dc plasma spectrometry and apply a correction to determine low tantalum concentrations with good accuracy and precision. Tantalum can be determined down to 0.4 ppM in solution with a relative standard deviation of 10 percent. Better precision can be achieved at higher concentrations. The procedure is simple and convenient for glovebox work. 5 references, 1 figure, 1 table

Bone remodeling around cementless tantalum cups

NARCIS (Netherlands)

Grillo, J. -C.; Flecher, X.; Bouvenot, J.; Argenson, J. -N.

2008-01-01

Purpose of the study.-Most studies have reported a significant decrease in periacetabular bone stock one year after implantation of a cementless cup. The purpose of this work was to study the bone-implant interface of the tantalum cup using plain X-rays and dual-energy X-ray absorptiometry (DEXA).

The recovery of tin, and the production of niobium pentoxide and potassium tantalum fluoride, from a tin slag

International Nuclear Information System (INIS)

Iorio, G.; Tyler, M.S.

1987-01-01

This report describes the results of testwork on the recovery of tin, niobium, and tantalum from a tin slag. The slag, which consisted mainly of amorphous silica, with varying amounts of calcuim, magnesium, manganese, iron, and aluminium, contained an average of 8,8 per cent niobium pentoxide and 6,2 per cent tantalum pentoxide. The metallic tin-ion phase was removed from the crushed slag by magnetic separation. The slag was then leached with hydrochloric acid to remove magnesium, calcium, aluminium, iron, manganese, and the remainder of the tin. Leaching with sodium hydroxide for the removal of silica and phosphorous was followed by a final leach with hydrochloric acid for the removal of sodium. The upgraded concentrate thus obtained was purified by leaching with hydrofluoric acid, solvent extraction of niobium and tantalum into tri-n-butyl phosphate and methyl isobutyl ketone, and selective stripping of niobium with sulphuric acid and tantalum with ammonium floride. Niobium pentoxide and potassium tantalum fluoride were then precipitated by the addition of ammonium hydroxide and potassium fluoride to the respective strip liquors. The overall recoveries in the upgraded concentrate were 98 per cent for tantalum and 92 per cent for niobium. Dissolutions and recoveries of over 99 per cent were obtained for both tantalum and niobium in the purification steps. The niobium pentoxide and potassium tantalum fluoride precipitates obtained were of high purity

Biomechanical Property of a Newly Designed Assembly Locking Compression Plate: Three-Dimensional Finite Element Analysis

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Jiang-Jun Zhou

2017-01-01

Full Text Available In this study, we developed and validated a refined three-dimensional finite element model of middle femoral comminuted fracture to compare the biomechanical stability after two kinds of plate fixation: a newly designed assembly locking compression plate (NALCP and a locking compression plate (LCP. CT data of a male volunteer was converted to middle femoral comminuted fracture finite element analysis model. The fracture was fixated by NALCP and LCP. Stress distributions were observed. Under slow walking load and torsion load, the stress distribution tendency of the two plates was roughly uniform. The anterolateral femur was the tension stress area, and the bone block shifted toward the anterolateral femur. Maximum stress was found on the lateral border of the number 5 countersink of the plate. Under a slow walking load, the NALCP maximum stress was 2.160e+03 MPa and the LCP was 8.561e+02 MPa. Under torsion load, the NALCP maximum stress was 2.260e+03 MPa and the LCP was 6.813e+02 MPa. Based on those results of finite element analysis, the NALCP can provide adequate mechanical stability for comminuted fractures, which would help fixate the bone block and promote bone healing.

Laser welding of a beryllium/tantalum collimator

International Nuclear Information System (INIS)

Lingenfelter, A.C.; Anglin, C.D.

1985-01-01

This report describes the methods utilized in the fabrication of a collimator from 0.001 inch thick beryllium and tantalum foil. The laser welding process proved to be an acceptable method for joining the beryllium in a standing edge joint configuration

Intercalated compounds of niobium and tantalum dicalcogenides

International Nuclear Information System (INIS)

Wypych, F.

1988-01-01

The synthesis of niobium and tantalum lamellar compounds and its intercalated derivatives is described. The intercalated compounds with lithium, with alkaline metal and with metals of the first-row transition are studied, characterized by X-ray diffraction. (C.G.C.) [pt

A preliminary deposit model for lithium-cesium-tantalum (LCT) pegmatites

Science.gov (United States)

Bradley, Dwight; McCauley, Andrew

2013-01-01

This report is part of an effort by the U.S. Geological Survey to update existing mineral deposit models and to develop new ones. We emphasize practical aspects of pegmatite geology that might directly or indirectly help in exploration for lithium-cesium-tantalum (LCT) pegmatites, or for assessing regions for pegmatite-related mineral resource potential. These deposits are an important link in the world’s supply chain of rare and strategic elements, accounting for about one-third of world lithium production, most of the tantalum, and all of the cesium.

The Additively Manufactured Porous NiTi and Ti-6Al-4V in Mandibular Reconstruction: Introducing the Stiffness-Matched and the Variable Stiffness Options for the Reconstruction Plates

Science.gov (United States)

Jahadakbar, Ahmadreza

Mandibular reconstruction surgery is a part of treatment for cancer, tumor, and all the cases that involve segmental defects. One of the most common approaches for the reconstruction surgery is to resect the segmental defect and use a double barrel fibula graft to fill the resected region and recover the mandible's normal functions, such as chewing. The grafted bone is connected to the host mandible, using the standard of the care Ti-6Al-4V fixation plates. The fixation plates are available in the form of prefabricated plates and also patient-specific plates in the market. Due to the high stiffness of the Ti-6Al-4V plates in comparison with the mandible bone and the grafted bone, the loading distribution on the whole reconstructed mandible will be different from a healthy mandible. The high stiffness fixation hardware carries a great portion of the loading and causes stress shielding on the grafted bone and the surrounding host bone. Based on the bone remodeling theory, the stress shielding on the cortical bone causes bone resorption and may lead to implant failure. A solution to reduce the risk of implant failure is to use a low stiffness biocompatible material for the mandibular fixation plates. We have proposed the use of stiffness-matched, porous NiTi fixation plates either in the form of patient-specific or prefabricated, instead of the standard of the care Ti-6Al-4V plates. NiTi is a biocompatible material that has a low stiffness in comparison with Ti-6Al-4V and also benefits from the superelastic feature. Superelasticity, which can also be found in bone tissues, allows the material to recover large strains (up to 8%) and increases the shock absorption. In this thesis, we have evaluated the use of proposed fixation hardware by comparing it with a healthy mandible and a reconstructed mandible using the standard method. To this end, first different models including a healthy mandible, a reconstructed mandible using patient-specific Ti-6Al-4V fixation hardware

Effects of hook plate on shoulder function after treatment of acromioclavicular joint dislocation.

Science.gov (United States)

Chen, Chang-Hong; Dong, Qi-Rong; Zhou, Rong-Kui; Zhen, Hua-Qing; Jiao, Ya-Jun

2014-01-01

Internal fixation with hook plate has been used to treat acromioclavicular joint dislocation. This study aims to evaluate the effect of its use on shoulder function, to further analyze the contributing factors, and provide a basis for selection and design of improved internal fixation treatment of the acromioclavicular joint dislocation in the future. A retrospective analysis was performed on patients treated with a hook plate for acromioclavicular joint dislocation in our hospital from January 2010 to February 2013. There were 33 cases in total, including 25 males and 8 females, with mean age of 48.27 ± 8.7 years. There were 29 cases of Rockwood type III acromioclavicular dislocation, 4 cases of type V. The Constant-Murley shoulder function scoring system was used to evaluate the shoulder function recovery status after surgery. Anteroposterior shoulder X-ray was used to assess the position of the hook plate, status of acromioclavicular joint reduction and the occurrence of postoperative complications. According to the Constant-Murley shoulder function scoring system, the average scores were 78 ± 6 points 8 to 12 months after the surgery and before the removal of the hook plate, the average scores were 89 ± 5 minutes two months after the removal of hook plate. Postoperative X-ray imaging showed osteolysis in 10 cases (30.3%), osteoarthritis in six cases (18.1%), osteolysis associated with osteoarthritis in four cases(12.1%), and steel hook broken in one case (3%). The use of hook plate on open reduction and internal fixation of the acromioclavicular joint dislocation had little adverse effect on shoulder function and is an effective method for the treatment of acromioclavicular joint dislocation. Osteoarthritis and osteolysis are the two common complications after hook plate use, which are associated with the impairment of shoulder function. Shoulder function will be improved after removal of the hook plate.

Pedicle screw-rod fixation: a feasible treatment for dogs with severe degenerative lumbosacral stenosis.

Science.gov (United States)

Tellegen, Anna R; Willems, Nicole; Tryfonidou, Marianna A; Meij, Björn P

2015-12-07

Degenerative lumbosacral stenosis is a common problem in large breed dogs. For severe degenerative lumbosacral stenosis, conservative treatment is often not effective and surgical intervention remains as the last treatment option. The objective of this retrospective study was to assess the middle to long term outcome of treatment of severe degenerative lumbosacral stenosis with pedicle screw-rod fixation with or without evidence of radiological discospondylitis. Twelve client-owned dogs with severe degenerative lumbosacral stenosis underwent pedicle screw-rod fixation of the lumbosacral junction. During long term follow-up, dogs were monitored by clinical evaluation, diagnostic imaging, force plate analysis, and by using questionnaires to owners. Clinical evaluation, force plate data, and responses to questionnaires completed by the owners showed resolution (n = 8) or improvement (n = 4) of clinical signs after pedicle screw-rod fixation in 12 dogs. There were no implant failures, however, no interbody vertebral bone fusion of the lumbosacral junction was observed in the follow-up period. Four dogs developed mild recurrent low back pain that could easily be controlled by pain medication and an altered exercise regime. Pedicle screw-rod fixation offers a surgical treatment option for large breed dogs with severe degenerative lumbosacral stenosis with or without evidence of radiological discospondylitis in which no other treatment is available. Pedicle screw-rod fixation alone does not result in interbody vertebral bone fusion between L7 and S1.

A PROSPECTIVE STUDY ON FUNCTIONAL OUTCOME OF HUMERUS SHAFT FRACTURES TREATED WITH OPEN REDUCTION AND INTERNAL FIXATION WITH DYNAMIC COMPRESSION PLATE AND SCREWS

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Vidyadhar S. Donimath

2017-12-01

Full Text Available BACKGROUND Fracture of the humerus shaft accounts to 3% to 5% of all fractures. Majority of the fractures are unstable due to distraction force of the gravity in the upper limb and strong muscle contraction leading to displacement. Internal fixation and early mobilisation is more stressed on than splinting and prolonged immobilisation to allow earlier mobilisation and rapid return to work. The aim of the study was to study the union rates and the functional outcome and complications associated with shaft humerus fractures in KIMS Hospital. MATERIALS AND METHODS A prospective study which was carried out from October 2015 to September 2017 in Karnataka Institute of Medical Sciences, Hubballi, Karnataka State, India. In this study period, 25 cases of fracture shaft of the humerus were treated by open reduction and internal fixation using DCP. Skeletally mature patients with fresh humerus diaphysis fractures were included in the study. Pathological fractures and Tscherne grade 2 and above, Gustilo Anderson type2 and above were excluded from the study. RESULTS In our series of 25 cases, there were 21 men and 4 women with average age of 42.5 years. Sixteen (64% cases were due to RTA and with predominance of right side. Transverse fractures were most common that is 15 (60% patients. Eleven (31% cases were having associated injuries. 92% of the fractures united with good to excellent outcome. There were 2 (8% cases of non-union due to infection and comminution. CONCLUSION Open reduction and internal fixation with dynamic compression plate is still the standard treatment of choice for fracture shaft of humerus achieving excellent to good functional outcome.

Oxidation and Volatilization from Tantalum Alloy T-222 During Air Exposure

Energy Technology Data Exchange (ETDEWEB)

Smolik, Galen Richard; Petti, David Andrew; Sharpe, John Phillip; Schuetz, Stanley Thomas

2000-10-01

Tantalum alloys are one of the refractory metals with renewed consideration for high temperatures in fusion reactor applications. Tantalum alloys perform well in protective environments but oxidized readily in gases containing higher oxygen levels. In addition, the radioactive isotope Ta-182 would be produced in tantalum and could be a significant contributor to dose if mobilized. Other isotopes of importance are produced from tungsten and hafnium. Mobilization of activated products during an accident with air ingress is therefore a safety issue. In this study, we measured the extent of oxidation and mobilization from tantalum alloy T-222 oxidized in flowing air between 500 and 1200°C. This alloy nominally contains 10 wt% tungsten, 2.5 wt% hafnium and 0.01 wt% carbon. We found that the mobilization of Ta and Hf was closely linked to the occurrence of oxide spalling. These elements showed no migration from the test chamber. Some W was mobilized by volatilization as evidenced by transport from the chamber. Tungsten volatilization could occur primarily during initial stages of oxidation before an oxide scale forms and impedes the process. The mobilization of Ta and W are presented in terms of the mass flux (g/m 2 -h) as a function of test temperature. These measurements along with specific designs, activation calculations, and accident scenarios provide information useful for dose calculations of future fusion devices

Oxidation and Volatilization from Tantalum Alloy T-222 During Air Exposure

Energy Technology Data Exchange (ETDEWEB)

Smolik, G.R.; Petti, D.A.; Sharpe, J.P.; Schuetz, S.T.

2000-10-31

Tantalum alloys are one of the refractory metals with renewed consideration for high temperatures in fusion reactor applications. Tantalum alloys perform well in protective environments but oxidized readily in gases containing higher oxygen levels. In addition, the radioactive isotope Ta-182 would be produced in tantalum and could be a significant contributor to dose if mobilized. Other isotopes of importance are produced from tungsten and hafnium. Mobilization of activated products during an accident with air ingress is therefore a safety issue. In this study, we measured the extent of oxidation and mobilization from tantalum alloy T-222 oxidized in flowing air between 500 and 1200 C. This alloy nominally contains 10 wt% tungsten, 2.5 wt% hafnium and 0.01 wt% carbon. We found that the mobilization of Ta and Hf was closely linked to the occurrence of oxide spalling. These elements showed no migration from the test chamber. Some W was mobilized by volatilization as evidenced by transport from the chamber. Tungsten volatilization could occur primarily during initial stages of oxidation before an oxide scale forms and impedes the process. The mobilization of Ta and W are presented in terms of the mass flux (g/m 2 -h) as a function of test temperature. These measurements along with specific designs, activation calculations, and accident scenarios provide information useful for dose calculations of future fusion devices.

Recovery of hafnium radioisotopes from a proton irradiated tantalum target

International Nuclear Information System (INIS)

Taylor, W.A.; Garcia, J.G.; Hamilton, V.T.; Heaton, R.C.; Jamriska, D.J.; Ott, M.A.; Philips, D.R.; Radzinski, S.D.

1998-01-01

The 178m2 Hf nucleus, with its long half-life (31 y) and high-spin isomeric state (16 + ) is desired for new and exotic nuclear physics studies. The Los Alamos Radioisotope Program irradiated a kilogram of natural tantalum at the Los Alamos Meson Physics Facility in early 1981. After fifteen years of decay, this target was ideal for the recovery of 178m2 Hf. There was more than a millicurie of 178m2 Hf produced during this irradiation and there has been a sufficient period of time for most of the other hafnium radioisotopes to decayed away. Traditionally, separation techniques for recovering hafnium isotopes from tantalum targets employ solvent extractions with reagents that are considered hazardous. These techniques are no longer condoned because they generate a mixed-waste (radioactive and hazardous components) that can not be treated for disposal. In this paper we describe a new and unique procedure for the recovery of hafnium radioisotopes from a highly radioactive, proton irradiated, tantalum target using reagents that do not contribute a hazardous waste component. (author)

A Novel Method for Assessment of Polyethylene Liner Wear in Radiopaque Tantalum Acetabular Cups

DEFF Research Database (Denmark)

Troelsen, Anders; Greene, Meridith E; Ayers, David C

2015-01-01

Conventional radiostereometric analysis (RSA) for wear is not possible in patients with tantalum cups. We propose a novel method for wear analysis in tantalum cups. Wear was assessed by gold standard RSA and the novel method in total hip arthroplasty patients enrolled in a randomized controlled...

Catalytic Hydroamination of Alkynes and Norbornene with Neutral and Cationic Tantalum Imido Complexes

Science.gov (United States)

Anderson, Laura L.; Arnold, John; Bergman, Robert G.

2005-01-01

Several tantalum imido complexes have been synthesized and shown to efficiently catalyze the hydroamination of internal and terminal alkynes. An unusual hydroamination/hydroarylation reaction of norbornene catalyzed by a highly electrophilic cationic tantalum imido complex is also reported. Factors affecting catalyst activity and selectivity are discussed along with mechanistic insights gained from stoichiometric reactions. PMID:15255680

Free flap reconstructions of tibial fractures complicated after internal fixation.

Science.gov (United States)

Nieminen, H; Kuokkanen, H; Tukiainen, E; Asko-Seljavaara, S

1995-04-01

The cases of 15 patients are presented where microvascular soft-tissue reconstructions became necessary after internal fixation of tibial fractures. Primarily, seven of the fractures were closed. Eleven fractures had originally been treated by open reduction and internal fixation using plates and screws, and four by intramedullary nailing. All of the patients suffered from postoperative complications leading to exposure of the bone or fixation material. The internal fixation material was removed and radical revision of dead and infected tissue was carried out in all cases. Soft tissue reconstruction was performed using a free microvascular muscle flap (11 latissimus dorsi, three rectus abdominis, and one gracilis). In eight cases the nonunion of the fracture indicated external fixation. The microvascular reconstruction was successful in all 15 patients. In one case the recurrence of deep infection finally indicated a below-knee amputation. In another case, chronic infection with fistulation recurred postoperatively. After a mean follow-up of 26 months the soft tissue coverage was good in all the remaining 13 cases. All the fractures united. Microvascular free muscle flap reconstruction of the leg is regarded as a reliable method for salvaging legs with large soft-tissue defects or defects in the distal leg. If after internal fixation of the tibial fracture the osteosynthesis material or fracture is exposed, reconstruction of the soft-tissue can successfully be performed by free flap transfer. By radical revision, external fixation, bone grafting, and a free flap the healing of the fracture can be achieved.

Swelling and tensile properties of EBR-II-irradiated tantalum alloys for space reactor applications

International Nuclear Information System (INIS)

Grossbeck, M.L.; Wiffen, F.W.

1985-01-01

The tantalum alloys T-111, ASTAR-811C, Ta-10 W, and unalloyed tantalum were examined following EBR-II irradiation to a fluence of 1.7 x 10 26 neutrons/m 2 (E > 0.1 MeV) at temperatures from 650 to 950 K. Swelling was found to be negligible for all alloys; only tantalum was found to exhibit swelling, 0.36%. Tensile testing revealed that irradiated T-111 and Ta-10 W are susceptible to plastic instability, but ASTAR-811C and tantalum were not. The tensile properties of ASTAR-811C appeared adequate for current SP-100 space nuclear reactor designs. Irradiated, oxygen-doped T-111 exhibited no plastic deformation, and the abrupt failure was intergranular in nature. The absence of plastic instability in ASTAR-811C is encouraging for alloys containing carbide precipitates. These fine precipitates might prevent dislocation channeling, which leads to plastic instability in many bcc metals after irradiation. 10 refs., 13 figs., 8 tabs

Minimally invasive treatment of pilon fractures with a low profile plate: preliminary results in 17 cases.

Science.gov (United States)

Borens, Olivier; Kloen, Peter; Richmond, Jeffrey; Roederer, Goetz; Levine, David S; Helfet, David L

2009-05-01

To determine the results of "biologic fixation" with a minimally invasive plating technique using a newly designed low profile "Scallop" plate in the treatment of pilon fractures. Retrospective case series. A tertiary referral center. Seventeen patients were treated between 1999 and 2001 for a tibial plafond fracture at the Hospital for Special Surgery with a newly designed low-profile plate. Eleven of the fractures (65%) were high-energy injuries. Two fractures were open. Staged surgical treatment with open reduction and fixation of the fibular fracture and application of an external fixator was performed in 12 cases. As soon as the soft tissues and swelling allowed, i.e. skin wrinkling, the articular surface was reconstructed and simply reduced, if necessary through an small incision, and the articular block was fixed to the diaphysis using a medially placed, percutaneously introduced flat scallop plate. In the remaining five cases the operation was performed in one session. Time to healing and complications including delayed union, non-union, instrument failure, loss of fixation, infection, quality of reduction and number of reoperations were evaluated. Quality of results and outcome were graded using the ankle-hindfoot-scale and a modified rating system. All patients went on to bony union at an average time of 14 weeks. There were no plate failures or loss of fixation/reduction. Two superficial wound-healing problems resolved with local wound care. At an average follow up of 17 months (range 6-29 months) eight patients (47%) had an excellent result; seven (41%) had a fair result whereas two (12%) had a poor result. The average ankle-hindfoot-score was 86.1 (range 61-100). Four patients have had the hardware removed and one of them is awaiting an ankle arthrodesis. Based on these initial results, it appears that a minimally invasive surgical technique including new low profile plate can decrease soft tissue problems while leading to fracture healing and

Sputter deposition of tantalum-nitride films on copper using an rf-plasma

International Nuclear Information System (INIS)

Walter, K.C.; Fetherston, R.P.; Sridharan, K.; Chen, A.; Shamim, M.M.; Conrad, J.R.

1994-01-01

A tantalum-nitride film was successfully deposited at ambient temperature on copper with a modified ion-assisted-deposition (IAD) technique. The process uses an argon and nitrogen plasma to sputter deposit from a tantalum rf-cathode and ion implant the deposited film simultaneously. Both argon and nitrogen ions are used for sputtering and ion implantation. Auger spectroscopy and x-ray diffraction were used to characterize the resulting film

Posterior coronal plating for tibial fractures: technique and advantages

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Montu Jain

2014-04-01

Full Text Available Objective:Tibial shaft fractures are straightforward to treat but when associated with soft tissue injury particularly at the nail entry/plate insertion site or there is significant comminution proximally or a large butterfly fragment/a second split component in the posterior coronal plane, it is a challenge to the treating surgeon. The aim of the present report is to describe the technique of posterior coronal plating in such a scenario and its advantages. Methods:Between July 2008 and June 2011, 12 patients were pro spectively treated by this approach using 4.5 mm broad dynamic compression plates. Results:The time of bony consolidation and full weight bearing averaged 21.7 weeks (range, 16-26 weeks. Patients were followed up for at least 24 months (range, 24-48 months. At 1 year postoper atively, no loss in reduction or alignment was observed. Mean Hospital for Lower Extremity Measurement Functional Score was 72.8 (range, 64-78. All patients were satisfied with their treatment outcomes. Conclusion:Direct posterior approach and fixation using prone position helps to visualise the fracture fragments and provide rigid fixation. The approach is simple and extensile easily, apart from advantages of less soft tissue and hardware problems compared to standard medial or lateral plating. Key words: Tibial fractures; Bone plates; Orthopedic procedures

A Novel Biodegradable Polycaprolactone Fixator for Osteosynthesis Surgery of Rib Fracture: In Vitro and in Vivo Study

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Yi-Hsun Yu

2015-11-01

Full Text Available Osteosynthesis surgery for rib fractures is controversial and challenging. This study developed a noval poly(ε-caprolactone (PCL-based biodegradable “cable-tie” fixator for osteosynthesis surgery for rib fractures. A biodegradable fixator specifically for fractured ribs was designed and fabricated by a micro-injection molding machine in our laboratory. The fixator has three belts that could be passed through matching holes individually. The locking mechanism allows the belt movement to move in only one direction. To examine the in vitro biomechanical performance, ribs 3–7 from four fresh New Zealand rabbits were employed. The load to failure and stress-strain curve was compared in the three-point bending test among native ribs, titanium plate-fixed ribs, and PCL fixator-fixed ribs. In the in vivo animal study, the sixth ribs of New Zealand rabbits were osteotomized and osteosynthesis surgery was performed using the PCL fixator. Outcomes were assessed by monthly X-ray examinations, a final micro-computed tomography (CT scan, and histological analysis. The experimental results suggested that the ribs fixed with the PCL fixator were significantly less stiff than those fixed with titanium plates (p < 0.05. All ribs fixed with the PCL fixators exhibited union. The bridging callus was confirmed by gross, radiographic micro-three-dimensional (3D CT, and histological examinations. In addition, there was no significant inflammatory response of the osteotomized ribs or the PCL-rib interface during application. The novel PCL fixator developed in this work achieves satisfactory results in osteosynthesis surgery for rib fractures, and may provide potential applications in other orthopedic surgeries.

Review of tantalum and niobium alloy production

International Nuclear Information System (INIS)

Buckman, R.W. Jr.

1984-01-01

This paper concentrates on the current state of niobium- and tantalum-base alloy production. The materials requirements, alloy compositions of interest, and production status are discussed. Finally, a list of developments needed to support the SP-100 program will be identified. A bibliography is included

Biomechanical evaluation of an integrated fixation cage during fatigue loading: a human cadaver study.

Science.gov (United States)

Palepu, Vivek; Peck, Jonathan H; Simon, David D; Helgeson, Melvin D; Nagaraja, Srinidhi

2017-04-01

OBJECTIVE Lumbar cages with integrated fixation screws offer a low-profile alternative to a standard cage with anterior supplemental fixation. However, the mechanical stability of integrated fixation cages (IFCs) compared with a cage with anterior plate fixation under fatigue loading has not been investigated. The purpose of this study was to compare the biomechanical stability of a screw-based IFC with a standard cage coupled with that of an anterior plate under fatigue loading. METHODS Eighteen functional spinal units were implanted with either a 4-screw IFC or an anterior plate and cage (AP+C) without integrated fixation. Flexibility testing was conducted in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) on intact spines, immediately after device implantation, and post-fatigue up to 20,000 cycles of FE loading. Stability parameters such as range of motion (ROM) and lax zone (LZ) for each loading mode were compared between the 2 constructs at multiple stages of testing. In addition, construct loosening was quantified by subtracting post-instrumentation ROM from post-fatigue ROM. RESULTS IFC and AP+C configurations exhibited similar stability (ROM and LZ) at every stage of testing in FE (p ≥ 0.33) and LB (p ≥ 0.23) motions. In AR, however, IFCs had decreased ROM compared with AP+C constructs at pre-fatigue (p = 0.07) and at all post-fatigue time points (p ≤ 0.05). LZ followed a trend similar to that of ROM in AR. ROM increased toward intact motion during fatigue cycling for AP+C and IFC implants. IFC specimens remained significantly (p < 0.01) more rigid than specimens in the intact condition during fatigue for each loading mode, whereas AP+C construct motion did not differ significantly (p ≥ 0.37) in FE and LB and was significantly greater (p < 0.01) in AR motion compared with intact specimens after fatigue. Weak to moderate correlations (R 2 ≤ 56%) were observed between T-scores and construct loosening, with lower T

Change in lattice parameter of tantalum due to dissolved hydrogen

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Gyanendra P. Tiwari

2012-06-01

Full Text Available The volume expansion of tantalum due to the dissolved hydrogen has been determined using Bragg equation. The hydrogen was dissolved in the pure tantalum metal at constant temperature (360 °C and constant pressure (132 mbar by varying the duration of hydrogen charging. The amount of dissolved hydrogen was within the solid solubility limit. The samples with different hydrogen concentration were analyzed by X-ray diffraction technique. Slight peak shifts as well as peak broadening were observed. The relative changes of lattice parameters plotted against the hydrogen concentration revealed that the lattice parameters varied linearly with the hydrogen concentration.

[Short-term curative effects of Tantalum rod treatment in early avascular necrosis].

Science.gov (United States)

Ye, Fu-Sheng; Ni, Zhe-Ji; Chu, Xiao-Bing; He, Bang-Jian; Li, Ju; Tong, Pei-Jian

2013-08-01

To explore the recent clinical curative effect of Tantalum rod in treating the early avascular necrosis. From January 2008 to November 2008, the 25 patients (39 hips) with early avascular necrosis accepted tantalum rod placement and included 9 males (11 hips) and 16 females (28 hips) with an average age of 37 years old ranging from 18 to 74 years old. Four patients (6 hips) caused by Alcoholic, 6 patients (8 hips) by hormone, 2 cases (2 hips) by traumatic, 13 cases (23 hips) by idiopathic. Steinberg preoperative stage involved 7 hips in period I, 24 hips in period II, 8 hips in period III. Curative effect analysis included preoperative and postoperative Harris score, radiographic changes and hip replacement for follow-up to accept the end of the femoral head survival rate. All patients were followed up for 6 to 47 months (averaged 37.4 months). All 12 hips imaging appeard progress,including tantalum rod exit in 1 hip, hip hemiarthroplasty collapse in 3 hips, the area increased to avascular necrosis in 8 hips. Six hips accepted total hip replacement, including imaging progress in 5 hips (41.7%, 5/12), no imaging progress in 1 hip (3.7%,1/27). All hips' Kaplan-Meier survival curves showed 6-month survival rate was (97.4 +/- 2.5)% after tantalum stick insertion, 1-year survival rate was (94.7 +/- 3.6), and 2-year survival rate was (88.6 +/- 5.4)%, 3-year survival rate was (72.5 +/- 11.2). It is effective for treatment of avascular necrosis of femoral head in Steinberg I and II by Tantalum rod, and it can effectively relieve femoral head replacement time.

Ender’s Nail fixation in paediatric femoral shaft fractures.

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Rajeev Dwivedi

2013-12-01

Flynn criteria 34 had excellent and 6 had satisfactory results. No poor results were seen. Conclusion: Ender’s nail fixation can be preferred method of treatment for femoral shaft fractures in age group 5 -15 years as the results are excellent and satisfactory. It is technically simple and can be done in a closed manner. It spares the vascularity and growth plate.

Clinical efficacy of open reduction and semirigid internal fixation in management of displaced pediatric mandibular fractures: A series of 10 cases and surgical guidelines

OpenAIRE

Samir Joshi; Rajesh Kshirsagar; Akshay Mishra; Rahul Shah

2015-01-01

Aim: To evaluate the efficacy of open reduction and semirigid internal fixation in the management of displaced pediatric mandibular fractures. Method: Ten patients with displaced mandibular fractures treated with 1.5 mm four holed titanium mini-plate and 4 mm screws which were removed within four month after surgery. Results: All cases showed satisfactory bone healing without any growth disturbance. Conclusion: Open reduction and rigid internal fixation (ORIF) with 1.5 mm titanium mini- plate...

The effects of argon ion bombardment on the corrosion resistance of tantalum

Science.gov (United States)

Ramezani, A. H.; Sari, A. H.; Shokouhy, A.

2017-02-01

Application of ion beam has been widely used as a surface modification method to improve surface properties. This paper investigates the effect of argon ion implantation on surface structure as well as resistance against tantalum corrosion. In this experiment, argon ions with energy of 30 keV and in doses of 1 × 1017-10 × 1017 ions/cm2 were used. The surface bombardment with inert gases mainly produces modified topography and morphology of the surface. Atomic Force Microscopy was also used to patterned the roughness variations prior to and after the implantation phase. Additionally, the corrosion investigation apparatus wear was applied to compare resistance against tantalum corrosion both before and after ion implantation. The results show that argon ion implantation has a substantial impact on increasing resistance against tantalum corrosion. After the corrosion test, scanning electron microscopy (SEM) analyzed the samples' surface morphologies. In addition, the elemental composition is characterized by energy-dispersive X-ray (EDX) analysis. The purpose of this paper was to obtain the perfect condition for the formation of tantalum corrosion resistance. In order to evaluate the effect of the ion implantation on the corrosion behavior, potentiodynamic tests were performed. The results show that the corrosion resistance of the samples strongly depends on the implantation doses.

An exploration in mineral supply chain mapping using tantalum as an example

Science.gov (United States)

Soto-Viruet, Yadira; Menzie, W. David; Papp, John F.; Yager, Thomas R.

2013-01-01

This report uses the supply chain of tantalum (Ta) to investigate the complexity of mineral and metal supply chains in general and show how they can be mapped. A supply chain is made up of all the manufacturers, suppliers, information networks, and so forth, that provide the materials and parts that go into making up a final product. The mineral portion of the supply chain begins with mineral material in the ground (the ore deposit); extends through a series of processes that include mining, beneficiation, processing (smelting and refining), semimanufacture, and manufacture; and continues through transformation of the mineral ore into concentrates, refined mineral commodities, intermediate forms (such as metals and alloys), component parts, and, finally, complex products. This study analyses the supply chain of tantalum beginning with minerals in the ground to many of the final goods that contain tantalum.

Assembly of tantalum porous films with graded oxidation profile from size-selected nanoparticles

Science.gov (United States)

Singh, Vidyadhar; Grammatikopoulos, Panagiotis; Cassidy, Cathal; Benelmekki, Maria; Bohra, Murtaza; Hawash, Zafer; Baughman, Kenneth W.; Sowwan, Mukhles

2014-05-01

Functionally graded materials offer a way to improve the physical and chemical properties of thin films and coatings for different applications in the nanotechnology and biomedical fields. In this work, design and assembly of nanoporous tantalum films with a graded oxidation profile perpendicular to the substrate surface are reported. These nanoporous films are composed of size-selected, amorphous tantalum nanoparticles, deposited using a gas-aggregated magnetron sputtering system, and oxidized after coalescence, as samples evolve from mono- to multi-layered structures. Molecular dynamics computer simulations shed light on atomistic mechanisms of nanoparticle coalescence, which govern the films porosity. Aberration-corrected (S) TEM, GIXRD, AFM, SEM, and XPS were employed to study the morphology, phase and oxidation profiles of the tantalum nanoparticles, and the resultant films.

Functional outcome of Schatzker type V and VI tibial plateau fractures treated with dual plates

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G Thiruvengita Prasad

2013-01-01

Full Text Available Background: Dual plate fixation in comminuted bicondylar tibial plateau fractures remains controversial. Open reduction and internal fixation, specifically through compromised soft tissues, has historically been associated with major wound complications. Alternate methods of treatment have been described, each with its own merits and demerits. We performed a retrospective study to evaluate the functional outcome of lateral and medial plate fixation of Schatzker type V and VI fractures through an anterolateral approach, and a medial minimally invasive approach or a posteromedial approach. Materials and Methods: We treated 46 tibial plateau fractures Schatzker type V and VI with lateral and medial plates through an anterolateral approach and a medial minimal invasive approach over an 8 years period. Six patients were lost to followup. Radiographs in two planes were taken in all cases. Immediate postoperative radiographs were assessed for quality of reduction and fixation. The functional outcome was evaluated according to the Oxford Knee Score criteria on followup. Results: Forty patients (33 men and 7 women who completed the followup were included in the study. There were 20 Schatzker type V fractures and 20 Schatzker type VI fractures. The mean duration of followup was 4 years (range 1-8 years. All patients had a satisfactory articular reduction defined as ≤2 mm step-off or gap as assessed on followup. All patients had a good coronal and sagittal plane alignment, and articular width as assessed on supine X-rays of the knee in the anteroposterior (AP and lateral views. The functional outcome, as assessed by the Oxford Knee Score, was excellent in 30 patients and good in 10 patients. All patients returned to their pre-injury level of activity and employment. There were no instances of deep infection. Conclusions: Dual plate fixation of severe bicondylar tibial plateau fractures is an excellent treatment option as it provides rigid fixation and

Transarticular fixation by hook plate versus coracoclavicular stabilization by single multistrand titanium cable for acute Rockwood grade-V acromioclavicular joint dislocation: a case-control study.

Science.gov (United States)

Gao, You-Shui; Zhang, Yue-Lei; Ai, Zi-Sheng; Sun, Yu-Qiang; Zhang, Chang-Qing; Zhang, Wei

2015-11-19

Hook plate (HP) is popularly used for acute and severely displaced acromioclavicular (AC) dislocations. However, subacromial impingement and acromion osteolysis induced by transarticular fixation are notorious. The current case-control study was to compare transarticular fixation by HP to coracoclavicular (CC) stabilization by single multistrand titanium cable (MSTC). Between January 2006 and August 2009, 24 patients with acute AC dislocations were surgically treated by open reduction and transarticular fixation with HP. These patients were matched to a series of 24 patients, who were managed by CC stabilization with MSTC in the same period. All AC dislocations were graded as Rockwood type V. Implant was removed 8-12 months after the primary operation in all patients, and 12 months at least were needed to assess the maintenance of AC joint. Functional results were evaluated before implant removal as well as in the last follow-up based on Constant-Murley criteria. There were no differences of demographic data including age, dominant gender and side, injury-to-surgery interval, operation time and follow-up period. In terms of functionality, Constant score was 95.8 ± 4.1 in MSTC group, while 76.7 ± 8.0 in HP group before implant removal (P acromioclavicular joint presented in 16 patients (66.7%) in patients treated by HP, while it was found in only 3 patients (12.5%) treated by MSTC (P acromioclavicular dislocation both before and after removal of the implant. Hardware removal is of great benefits for functional improvement in patients treated by HP.

Bone plate composed of a ternary nano-hydroxyapatite/polyamide 66/glass fiber composite: biomechanical properties and biocompatibility.

Science.gov (United States)

Qiao, Bo; Li, Jidong; Zhu, Qingmao; Guo, Shuquan; Qi, Xiaotong; Li, Weichao; Wu, Jun; Liu, Yang; Jiang, Dianming

2014-01-01

An ideal bone plate for internal fixation of bone fractures should have good biomechanical properties and biocompatibility. In this study, we prepared a new nondegradable bone plate composed of a ternary nano-hydroxyapatite/polyamide 66/glass fiber (n-HA/PA66/GF) composite. A breakage area on the n-HA/PA66/GF plate surface was characterized by scanning electron microscopy. Its mechanical properties were investigated using bone-plate constructs and biocompatibility was evaluated in vitro using bone marrow-derived mesenchymal stem cells. The results confirmed that adhesion between the n-HA/PA66 matrix and the glass fibers was strong, with only a few fibers pulled out at the site of breakage. Fractures fixed by the n-HA/PA66/GF plate showed lower stiffness and had satisfactory strength compared with rigid fixation using a titanium plate. Moreover, the results with regard to mesenchymal stem cell morphology, MTT assay, Alizarin Red S staining, enzyme-linked immunosorbent assay, and reverse transcription polymerase chain reaction for alkaline phosphatase and osteocalcin showed that the n-HA/PA66/GF composite was suitable for attachment and proliferation of mesenchymal stem cells, and did not have a negative influence on matrix mineralization or osteogenic differentiation of mesenchymal stem cells. These observations indicate that the n-HA/PA66/GF plate has good biomechanical properties and biocompatibility, and may be considered a new option for internal fixation in orthopedic surgery.

OUTCOME OF LOCKING PLATES IN DISTAL TIBIA FRACTURES TREATMENT

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Lokesh

2016-05-01

Full Text Available INTRODUCTION Most of these fractures except intra-articular fractures are treated with interlocking nail. 1,2 These nails are a boon for these fractures. But as the fracture nears to the joint stability the fracture fixation will be compromised due to malreduction and alignment, it leads to increased chances of delayed and nonunion. 3 Locking anatomical plates are evaluated for anatomical and relative stability fixation. Since then most intra and near intra-articular fractures are fixed with these plates with minimally invasive percutaneous plate osteosynthesis method, these plates have given excellent result 4 . But again these plates have some disadvantages 5 . This study is done to see the outcome of locking plates in distal tibia fracture. METHODS This study is done in the Department of Orthopaedics, Bangalore Medical College, Bangalore. This study is done from 2013 to 2015. 30 patients who came to outpatient department were treated with locking plates. All patients above 16 years having distal third tibia fracture are included. All open fractures except type 1 and elderly above 60 years and pathological fractures are excluded in our study. All patients were followed up for initial 5 months, thereafter, once in 3 months, for clinical and radiological evaluation of union status, knee range of motion, ankle range of motion and other complications. Assessment of the patient with functional recovery was done with American Orthopaedic Foot and Ankle Surgery(AOFAS 6 minimum 5 months after injury. RESULTS Majority of the patients are from age group 18-29 years (50%. Average age group was 30 years. Majority of the patients were males 80.6% (25. All fractures were closed fractures except 2 cases which are type 1. There were 12 cases of AO type A, 8 patients were AO type B and 10 patients were type C. Majority of the patients had fracture due to road traffic accidents, 74%. All fractures were united by the end of 20 weeks. There was delayed union in

New Sesame equation of state for tantalum

International Nuclear Information System (INIS)

Greeff, C. W.; Johnson, J. D.

2000-01-01

A new Sesame equation of state (EOS) table has been created for tantalum. This EOS incorporates new high pressure Hugoniot data and diamond anvil cell compression data. The new EOS gives better agreement with this data as well as with sound speeds and Hugoniot curves of porous samples

Cast and hipped gamma titanium aluminum alloys modified by chromium, boron, and tantalum

International Nuclear Information System (INIS)

Huang, Shyhchin.

1993-01-01

A cast body is described of a chromium, boron, and tantalum modified titanium aluminum alloy, said alloy consisting essentially of titanium, aluminum, chromium, boron, and tantalum in the following approximate atomic ratio: Ti-Al 45-50 Cr 1-3 Ta 1-8 B 0.1-0.3 , and said alloy having been prepared by casting the alloy to form said cast body and by HIPping said body

Tantalum-based multilayer coating on cobalt alloys in total hip and knee replacement

Energy Technology Data Exchange (ETDEWEB)

Balagna, C., E-mail: cristina.balagna@polito.it [Institute of Materials Engineering and Physics, Applied Science and Technology Department, Politecnico di Torino, Corso Duca degli Abruzzi 24,10129 Torino (Italy); Faga, M.G. [Istituto di Scienza e Tecnologia dei Materiali Ceramici, Consiglio Nazionale delle Ricerche, Strada delle Cacce 73, 10135 Torino (Italy); Spriano, S. [Institute of Materials Engineering and Physics, Applied Science and Technology Department, Politecnico di Torino, Corso Duca degli Abruzzi 24,10129 Torino (Italy)

2012-05-01

Cobalt-chromium-molybdenum (CoCrMo) alloys are widely used in total hip and knee joint replacement, due to high mechanical properties and resistance to wear and corrosion. They are able to form efficient artificial joints by means of coupling metal-on-polymer or metal-on-metal contacts. However, a high concentration of stress and direct friction between surfaces leads to the formation of polyethylene wear debris and the release of toxic metal ions into the human body, limiting, as a consequence, the lifetime of implants. The aim of this research is a surface modification of CoCrMo alloys in order to improve their biocompatibility and to decrease the release of metal ions and polyethylene debris. Thermal treatment in molten salts was the process employed for the deposition of tantalum-enriched coating. Tantalum and its compounds are considered biocompatible materials with low ion release and high corrosion resistance. Three different CoCrMo alloys were processed as substrates. An adherent coating of about 1 {mu}m of thickness, with a multilayer structure consisting of two tantalum carbides and metallic tantalum was deposited. The substrates and modified layers were characterized by means of structural, chemical and morphological analysis. Moreover nanoindentation, scratch and tribological tests were carried out in order to evaluate the mechanical behavior of the substrates and coating. The hardness of the coated samples increases more than double than the untreated alloys meanwhile the presence of the coating reduced the wear volume and rate of about one order of magnitude. - Highlights: Black-Right-Pointing-Pointer Thermal treatment in molten salts deposits a Ta-based coating on Co-based alloys. Black-Right-Pointing-Pointer Coating is composed by one or two tantalum carbides and/or metallic tantalum. Black-Right-Pointing-Pointer The coating structure depends on thermal temperature and substrates carbon content. Black-Right-Pointing-Pointer Coating is able to

Poisoning Experiments Aimed at Discriminating Active and Less-Active Sites of Silica-Supported Tantalum Hydride for Alkane Metathesis

KAUST Repository

Saggio, Guillaume

2010-10-04

Only 50% of the silica-supported tantalum hydride sites are active in the metathesis of propane. Indeed, more than 45% of the tantalum hydride can be eliminated by a selective oxygen poisoning of inactive sites with no significant decrease in the global turnover. Conversely, cyclopentane induces no such selective poisoning. Hence, the active tantalum hydride sites that show greater resistance to oxygen poisoning correspond to the νTa-H bands of higher wavenumbers, particularly that at 1860cm-1. These active tantalum hydride sites should correspond to tris- or monohydride species relatively far from silica surface oxygen atoms. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recovery of metal values and hydrofluoric acid from tantalum and columbium waste sludge

International Nuclear Information System (INIS)

Bielecki, E.; Romberger, K.; Bakke, B.; Hobin, M.A.; Clark, C.

1992-01-01

A metallurgical processing system for economically recovering metal values, such as columbium, tantalum, thorium, and uranium from dilute source solids, such as digestion sludges, by a series of steps including: (1) slurrying the source solids with dilute hydrofluoric acid to produce a solid phase and a liquid phase containing dissolved tantalum and columbium, then extracting tantalum and/or columbium from the liquid phase by means of a liquid ion-exchange process and then, additionally; (2) roasting the solid phase with sulfuric acid to recover and recycle hydrofluoric acid, leaching the roasted solids with dilute sulfuric acid to produce a disposable solid phase and a liquid phase containing thorium and uranium, and extracting thorium and uranium from the liquid phase by means of a liquid-liquid amine extraction process

Tantalum-containing Z-phase in 12%Cr martensitic steels

DEFF Research Database (Denmark)

Danielsen, Hilmar Kjartansson; Hald, John

2009-01-01

Z-phases in tantalum-containing 12%Cr steels have been investigated. In 12%Cr steel without any Nb or V, the formation of CrTaN Z-phases was observed. In 12%Cr steel which also contained V, the Ta entered Z-phase as a minor element, Cr(V,Ta)N. The crystal structure of Cr(V,Ta)N seems to be identi......Z-phases in tantalum-containing 12%Cr steels have been investigated. In 12%Cr steel without any Nb or V, the formation of CrTaN Z-phases was observed. In 12%Cr steel which also contained V, the Ta entered Z-phase as a minor element, Cr(V,Ta)N. The crystal structure of Cr(V,Ta)N seems...

An Overview of Internal and External Fixation Methods for the Diabetic Charcot Foot and Ankle.

Science.gov (United States)

Ramanujam, Crystal L; Zgonis, Thomas

2017-01-01

Diabetic Charcot neuroarthropathy (DCN) of the foot and ankle is a challenging disease with regard to clinical presentation, pathogenesis, and prognosis. Its surgical management is equally difficult to interpret based on the wide array of options available. In the presence of an ulceration or concomitant osteomyelitis, internal fixation by means of screws, plates, or intramedullary nailing needs to be avoided when feasible. External fixation becomes a great surgical tool when managing DCN with concomitant osteomyelitis. This article describes internal and external fixation methods along with available literature to enlighten surgeons faced with treating this complex condition. Copyright © 2016 Elsevier Inc. All rights reserved.

Evaluation of corrosion behaviour of tantalum coating obtained by low pressure chemical vapor deposition using electrochemical polarization

Science.gov (United States)

Levesque, A.; Bouteville, A.; de Baynast, H.; Laveissière, B.

2002-06-01

antalum coatings are elaborated on titanium substrates through Low Pressure Chemical Vapor Deposition from tantalum pentachloride-hydrogen gaseous phase at a deposition temperature of 800 °C and a total pressure of 3.3 mbar. The aim of this paper is to evaluate the effectiveness of this tantalum coating in corrosive solution. Optical Microscopy and Scanning Electron Microscopy observations reveal that deposits are of 1.7 μm in thickness and conformal. The corrosion resistance of tantalum coated titanium substrates is quantified through standard potentiodynamic polarization method. Even for tantalum coatings exhibiting some defects as pores, the corrosion current density is as low as 0.25 mA/cm^2.in very agressive solutions like kroll reagent (HN03/HF).

Effectiveness of plate augmentation for femoral shaft nonunion after nailing

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Chin-Jung Lin

2012-08-01

Conclusion: Plate augmentation with retention of the nail with autologous bone grafting may be an effective and reliable alternative in treating nonunion of the femoral shaft fracture after open reduction and internal fixation with intramedullary nail.

Effect of Reverse Bias Stress on Leakage Currents and Breakdown Voltages of Solid Tantalum Capacitors

Science.gov (United States)

Teverovsky, Alexander A.

2011-01-01

The majority of solid tantalum capacitors are produced by high-temperature sintering of a fine tantalum powder around a tantalum wire followed by electrolytic anodization that forms a thin amorphous Ta2O5 dielectric layer and pyrolysis of manganese nitrite on the oxide to create a conductive manganese dioxide electrode. A contact to tantalum wire is used as anode terminal and to the manganese layer as a cathode terminal of the device. This process results in formation of an asymmetric Ta -- Ta2O5 -- MnO2 capacitor that has different characteristics at forward (positive bias applied to tantalum) and reverse (positive bias applied to manganese cathode) voltages. Reverse bias currents might be several orders of magnitude larger than forward leakage currents so I-V characteristics of tantalum capacitors resemble characteristics of semiconductor rectifiers. Asymmetric I-V characteristics of Ta -- anodic Ta2O5 systems have been observed at different top electrode materials including metals, electrolytes, conductive polymers, and manganese oxide thus indicating that this phenomenon is likely related to the specifics of the Ta -- Ta2O5 interface. There have been multiple attempts to explain rectifying characteristics of capacitors employing anodic tantalum pentoxide dielectrics. A brief review of works related to reverse bias (RB) behavior of tantalum capacitors shows that the mechanism of conduction in Ta -- Ta2O5 systems is still not clear and more testing and analysis is necessary to understand the processes involved. If tantalum capacitors behave just as rectifiers, then the assessment of the safe reverse bias operating conditions would be a relatively simple task. Unfortunately, these parts can degrade with time under reverse bias significantly, and this further complicates analysis of the I-V characteristics and establishing safe operating areas of the parts. On other hand, time dependence of reverse currents might provide additional information for investigation of

A FUNCTIONAL EVALUATION STUDY OF DISTAL FEMORAL FRACTURES FIXED WITH DISTAL FEMORAL LOCKING PLATE

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Manikumar C. J

2017-04-01

Full Text Available BACKGROUND Fractures of the distal femur present considerable challenges in management. Older patients especially women sustain fractures due to osteoporosis. Supracondylar fractures of femur have a bimodal distribution. They account for 6% of all femur fractures and 31% if hip fractures were excluded. Nearly, 50% of distal femur intra-articular fractures are open fractures. Before 1970, most supracondylar fractures were treated nonoperatively; however, difficulties were often encountered including persistent angulatory deformity, knee joint incongruity, loss of knee motion and delayed mobilisation. The trend of open reduction and internal fixation has become evident in recent years with good results being obtained with AO blade plate, dynamic condylar screw, intramedullary supracondylar nail and locking compression plate. Elderly patients and osteoporosis pose difficulty in treating intra-articular fractures of the lower end of femur. Loss of stable fixation is of great concern in these cases. Hence, locking compression plate use has an advantage in these patients. MATERIALS AND METHODS In this study, 20 patients with closed fracture of distal femur were studied. All the cases were treated at the Department of Orthopaedics, Rangaraya Medical College/Government General Hospital, Kakinada, Andhra Pradesh, between November 2013 and November 2015. The method used for fracture fixation was open reduction and internal fixation with distal femoral locking plate. The duration of follow up ranged from 3 months to 24 months. All the fractures in this series were posttraumatic. The patients were functionally evaluated with Neer’s scoring system. 1 RESULTS Twenty distal femoral fractures were treated with distal femoral locking plates. 15 patients were males and 5 patients were females. The median age was 47 years ranging from 28-70 years. 16 of the fractures were caused by road traffic accidents and 2 were due to fall, 2 were due to assault. 12 patients

Self-reinforced bioresorbable poly-L/DL-lactide [SR-P(L/DL)LA] 70/30 miniplates and miniscrews are reliable for fixation of anterior mandibular fractures: a pilot study.

Science.gov (United States)

Ylikontiola, Leena; Sundqvuist, Kai; Sàndor, George K B; Törmälä, Pertti; Ashammakhi, Nureddin

2004-03-01

Bioresorbable osteofixation devices are being increasingly used in orthognathic surgery and in cases of trauma to avoid problems associated with conventional metal osteofixation devices. The aim of this clinical study was to assess the reliability and efficacy of bioresorbable self-reinforced poly-L/DL-lactide (SR-P(L/DL)LA 70/30) plates and screws in the fixation of mandibular fractures in adults. Ten patients (20 to 49 years old) with isolated anterior mandibular parasymphyseal fractures were treated by means of open reduction and internal fixation using SR-P(L/DL)LA 70/30 bioresorbable plates and screws. During the minimum of 6 months of follow-up, no problems were encountered except for 1 case where a plate became exposed intraorally and infected. This required debridement and later excision of the exposed part of the plate. Despite this setback the fractured bone healed well. SR-P(L/DL)LA 70/30 plates and screws are reliable for internal fixation of anterior mandibular fractures in adults. Proper soft tissue coverage should be ensured to avoid plate exposure. Should implant exposure occur, it might be necessary to excise the exposed part after fracture healing (6-8 weeks postoperatively).

Clustering of transmutation elements tantalum, rhenium and osmium in tungsten in a fusion environment

Science.gov (United States)

You, Yu-Wei; Kong, Xiang-Shan; Wu, Xuebang; Liu, C. S.; Fang, Q. F.; Chen, J. L.; Luo, G.-N.

2017-08-01

The formation of transmutation solute-rich precipitates has been reported to seriously degrade the mechanical properties of tungsten in a fusion environment. However, the underlying mechanisms controlling the formation of the precipitates are still unknown. In this study, first-principles calculations are therefore performed to systemically determine the stable structures and binding energies of solute clusters in tungsten consisting of tantalum, rhenium and osmium atoms as well as irradiation-induced vacancies. These clusters are known to act as precursors for the formation of precipitates. We find that osmium can easily segregate to form clusters even in defect-free tungsten alloys, whereas extremely high tantalum and rhenium concentrations are required for the formation of clusters. Vacancies greatly facilitate the clustering of rhenium and osmium, while tantalum is an exception. The binding energies of vacancy-osmium clusters are found to be much higher than those of vacancy-tantalum and vacancy-rhenium clusters. Osmium is observed to strongly promote the formation of vacancy-rhenium clusters, while tantalum can suppress the formation of vacancy-rhenium and vacancy-osmium clusters. The local strain and electronic structure are analyzed to reveal the underlying mechanisms governing the cluster formation. Employing the law of mass action, we predict the evolution of the relative concentration of vacancy-rhenium clusters. This work presents a microscopic picture describing the nucleation and growth of solute clusters in tungsten alloys in a fusion reactor environment, and thereby explains recent experimental phenomena.

Silicon transport in sputter-deposited tantalum layers grown under ion bombardment

International Nuclear Information System (INIS)

Gallais, P.; Hantzpergue, J.J.; Remy, J.C.; Roptin, D.

1988-01-01

Tantalum was sputter deposited on (111) Si substrate under low-energy ion bombardment in order to study the effects of the ion energy on the silicon transport into the Ta layer. The Si substrate was heated up to 500 0 C during growth. For ion energies up to 180 eV silicon is not transported into tantalum and the growth temperature has no effect. An ion bombardment energy of 280 eV enhances the transport of silicon throughout the tantalum layer. Growth temperatures up to 300 0 C have no effect on the silicon transport which is mainly enhanced by the ion bombardment. For growth temperatures between 300 and 500 0 C, the silicon transport is also enhanced by the thermal diffusion. The experimental depth distribution of silicon is similar to the theoretical depth distribution calculated for the case of an interdiffusion. The ion-enhanced process of silicon transport is characterized by an activation energy of 0.4 eV. Silicon into the layers as-grown at 500 0 C is in both states, amorphous silicide and microcrystalline cubic silicon

Fixation distance and fixation duration to vertical road signs.

Science.gov (United States)

Costa, Marco; Simone, Andrea; Vignali, Valeria; Lantieri, Claudio; Palena, Nicola

2018-05-01

The distance of first-fixation to vertical road signs was assessed in 22 participants while driving a route of 8.34 km. Fixations to road signs were recorded by a mobile eye-movement-tracking device synchronized to GPS and kinematic data. The route included 75 road signs. First-fixation distance and fixation duration distributions were positively skewed. Median distance of first-fixation was 51 m. Median fixation duration was 137 ms with a modal value of 66 ms. First-fixation distance was linearly related to speed and fixation duration. Road signs were gazed at a much closer distance than their visibility distance. In a second study a staircase procedure was used to test the presentation-time threshold that lead to a 75% accuracy in road sign identification. The threshold was 35 ms, showing that short fixations to a road signs could lead to a correct identification. Copyright © 2018 Elsevier Ltd. All rights reserved.

Obtainment of tantalum oxide from national ores

International Nuclear Information System (INIS)

Pinatti, D.G.; Ribeiro, S.; Martins, A.H.

1988-01-01

The experimental results of tantalum oxides (Ta 2 O 5 ) obtainment from Brazilian ores of tantalite and columbite are described. This study is a part of the technologic and scientific research design of refractory metals (Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W) and correlate ceramics. (C.G.C.) [pt

Tantalum coating of porous carbon scaffold supplemented with autologous bone marrow stromal stem cells for bone regeneration in vitro and in vivo.

Science.gov (United States)

Wei, Xiaowei; Zhao, Dewei; Wang, Benjie; Wang, Wei; Kang, Kai; Xie, Hui; Liu, Baoyi; Zhang, Xiuzhi; Zhang, Jinsong; Yang, Zhenming

2016-03-01

Porous tantalum metal with low elastic modulus is similar to cancellous bone. Reticulated vitreous carbon (RVC) can provide three-dimensional pore structure and serves as the ideal scaffold of tantalum coating. In this study, the biocompatibility of domestic porous tantalum was first successfully tested with bone marrow stromal stem cells (BMSCs) in vitro and for bone tissue repair in vivo. We evaluated cytotoxicity of RVC scaffold and tantalum coating using BMSCs. The morphology, adhesion, and proliferation of BMSCs were observed via laser scanning confocal microscope and scanning electron microscopy. In addition, porous tantalum rods with or without autologous BMSCs were implanted on hind legs in dogs, respectively. The osteogenic potential was observed by hard tissue slice examination. At three weeks and six weeks following implantation, new osteoblasts and new bone were observed at the tantalum-host bone interface and pores. At 12 weeks postporous tantalum with autologous BMSCs implantation, regenerated trabecular equivalent to mature bone was found in the pore of tantalum rods. Our results suggested that domestic porous tantalum had excellent biocompatibility and could promote new bone formation in vivo. Meanwhile, the osteogenesis of porous tantalum associated with autologous BMSCs was more excellent than only tantalum implantation. Future clinical studies are warranted to verify the clinical efficacy of combined implantation of this domestic porous tantalum associated with autologous BMSCs implantation and compare their efficacy with conventional autologous bone grafting carrying blood vessel in patients needing bone repairing. © 2016 by the Society for Experimental Biology and Medicine.

Complications and functional outcome after internal fixation of dorsally displaced distal radial fractures

DEFF Research Database (Denmark)

Bove, Jeppe; Viberg, Bjarke; Wied Greisen, Pernille

Background: Recently there has been an increasing interest in open reduction and internal fixation of distal radius fractures. Even so further studies are still needed. Purpose: To document the functional outcome and identify complica- tions among patients treated with a volar locking plate (DVR...

Porous tantalum coatings prepared by vacuum plasma spraying enhance bmscs osteogenic differentiation and bone regeneration in vitro and in vivo.

Directory of Open Access Journals (Sweden)

Ze Tang

Full Text Available Tantalum, as a potential metallic implant biomaterial, is attracting more and more attention because of its excellent anticorrosion and biocompatibility. However, its significantly high elastic modulus and large mechanical incompatibility with bone tissue make it unsuitable for load-bearing implants. In this study, porous tantalum coatings were first successfully fabricated on titanium substrates by vacuum plasma spraying (VPS, which would exert the excellent biocompatibility of tantalum and alleviate the elastic modulus of tantalum for bone tissue. We evaluated cytocompatibility and osteogenesis activity of the porous tantalum coatings using human bone marrow stromal cells (hBMSCs and its ability to repair rabbit femur bone defects. The morphology and actin cytoskeletons of hBMSCs were observed via electron microscopy and confocal, and the cell viability, proliferation and osteogenic differentiation potential of hBMSCs were examined quantitatively by PrestoBlue assay, Ki67 immunofluorescence assay, real-time PCR technology and ALP staining. For in vivo detection, the repaired femur were evaluated by histomorphology and double fluorescence labeling 3 months postoperation. Porous tantalum coating surfaces promoted hBMSCs adhesion, proliferation, osteogenesis activity and had better osseointegration and faster new bone formation rate than titanium coating control. Our observation suggested that the porous tantalum coatings had good biocompatibility and could enhance osseoinductivity in vitro and promote new bone formation in vivo. The porous tantalum coatings prepared by VPS is a promising strategy for bone regeneration.

Nonunion of the humerus following intramedullary nailing treated by Ilizarov hybrid fixation.

Science.gov (United States)

Raschke, M; Khodadadyan, C; Maitino, P D; Hoffmann, R; Südkamp, N P

1998-02-01

A case of a posttraumatic humeral shaft nonunion, after intramedullary stabilization with a Seidel nail, is presented. Severe osteoporosis, an oligotrophic nonunion, subclinical infection, and adhesive capsulitis of the glenohumeral joint were present. Due to the subclinical infection and severe osteoporosis, other major invasive therapeutic options such as intramedullary nailing or compression plating and bone grafting were not applicable. Nonoperative treatment was also not indicated secondary to the pain and disability present. External fixation with the Ilizarov hybrid fixator seemed to offer a minimally invasive treatment modality without the need of additional bone grafting. After fourteen weeks of "callus massage," consisting of closed alternating compression and distraction with an Ilizarov hybrid fixator, osseous consolidation was achieved. Eight months after Ilizarov treatment the patient had returned to work as a mechanic. At the one-year follow-up examination, the patient presented pain free and with near normal shoulder and elbow motion, with stable osseous consolidation of the humerus. In some cases of nonunion of the humerus shaft, when standard treatment options are not recommended, external fixation with an Ilizarov hybrid fixator may offer a salvage procedure with a successful clinical outcome.

[Biomechanical analysis on healing process of sagittal fracture of the mandibular condyle after rigid fixation].

Science.gov (United States)

Jing, Jie; Qu, Ai-li; Ding, Xiao-mei; Hei, Yu-na

2015-04-01

To analyze the biomechanical healing process on rigid fixation of sagittal fracture of the mandibular condyle (SFMC), and to provide guidelines for surgical treatment. Three-dimensional finite element model (3D-FEAM) of mandible and condyle was established. The right condyle was simulated as SFMC with 0.1 mm space across the condyle length ways. The 3D-FEAM of rigid fixation was established. The biomechanical factors such as stress distribution of condylar surface, displacement around fracture, stress on the plate and stress shielding were calculated during 0, 4, 8 and 12-week after rigid fixation. The maximum equivalent stress of normal condyle was located at the area of middle 1/3 of condylar neck. The maximum equivalent stress at 0-week after fixation was 23 times than that on normal condyle. They were located at the condylar stump and the plate near inferior punctual areas of fracture line. There were little stress on the other areas. The maximum equivalent stress at 4, 8 and 12-week was approximately 6 times than that on normal condyle. They were located at the areas same as the area at 0-week. There were little stress on the other areas at the condyle. The maximum total displacement and maximum total corner were increased 0.57-0.75 mm and 0.01-0.09° respectively during healing process. The maximum equivalent stress at 0-week on the condylar trump was 5-6 times compared with that at 4, 8, and 12-week. The maximum equivalent stress, maximum total displacement and maximum total corner on the fractured fragment were not changed significantly during healing process. The maximum equivalent stress at 0-week on the plate was 7-9 times compared with that at 4, 8, 12-week. The stress of the condyle and stress shielding of the plate may be the reasons of absorbing and rebuilding on the condyle in healing process of SFMC. The biomechanical parameters increase obviously at 4-week after fixation. Elastic intermaxillary traction is necessary to decrease total displacement

Antimicrobial activity of tantalum oxide coatings decorated with Ag nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Cao, Huiliang, E-mail: hlc@mail.sic.ac.cn; Meng, Fanhao; Liu, Xuanyong, E-mail: xyliu@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

2016-07-15

Silver plasma immersion ion implantation was used to decorate silver nanoparticles (Ag NPs) on tantalum oxide (TO) coatings. The coatings acted against bacterial cells (Staphylococcus epidermidis) in the dark by disrupting their integrity. The action was independent of silver release and likely driven by the electron storage capability of the Schottky barriers established at the interfaces between Ag NPs and the TO support. Moreover, no apparent side effect on the adhesion and differentiation of rat bone mesenchymal stem cells was detected when using Ag NPs-modified TO coatings. These results demonstrate that decoration of tantalum oxide using Ag NPs could be a promising procedure for improving the antibacterial properties for orthopedic and dental implants.

EVALUATION OF FUNCTIONAL OUTCOME AFTER OPEN REDUCTION AND INTERNAL FIXATION OF DISTAL FEMUR FRACTURES BY LOCKING COMPRESSION PLATE

Directory of Open Access Journals (Sweden)

L. Lokanadha Rao

2016-09-01

Full Text Available BACKGROUND In the supra and intercondylar fractures of femur particularly with intra articular extension, patient may develop stiffness of knee, shortening, rotational deformities, internal derangement of knee with instability, varus and valgus deformities which affect patient’s routine lifestyle. If these cases were treated with locking compression plate, the results obtained were successful, superior, timesaving providing early ambulation and least disability improving the functional outcome. MATERIALS AND METHODS This is a prospective interventional study. This study includes 25 supracondylar and intercondylar fractures of femur (both Muller’s Type ‘A’, Type B and Type ‘C’ fractures treated with open reduction and internal fixation by Locking Compression Plate in the Department of Orthopaedics, King George Hospital, Visakhapatnam from September 2013 to September 2015. There are 16 males and 9 females with age ranging from 20 to 80 years with an average of 44.6 years. Average age for males is 28.9 years and average age for females is 25 years. 18 fractures were due to road traffic accidents and 6 cases are due to fall from significant heights, 1 case due to simple fall from standing (osteoporosis. 15 cases were in right femur (60% and 10 cases were in left femur (40%. RESULTS 25 cases were included in the study. There is an increase in the rate of union, decreased time taken for union, increased knee range of motion, decreased time for weight-bearing, postoperative complications and duration for hospital stay. CONCLUSION LCP proved to be a good implant which could take the challenges like poor bone stock, severe comminution both metaphyseal and articular and prove successful. The locking head screws distally have prevented varus collapse, even in cases of osteoporosis. The Condylar LCP can be used in either an open or a minimally invasive manner.

Adult periarticular locking plates for the treatment of pediatric and adolescent subtrochanteric hip fractures.

Science.gov (United States)

Sanders, Samuel; Egol, Kenneth A

2009-01-01

Two cases are presented in which adult, precontoured, lower-extremity periarticular locking plates were utilized for fixation of subtrochanteric femur fractures in pediatric patients. Recognition of the fact that a distal tibial locking plate in a small child and a proximal tibial locking plate in an adolescent anatomically ft the proximal femur in each case may provide a surgeon treating subtrochanteric hip fractures in this population increased options for operative stabilization.

Activation analysis of trace amounts of rare earth in high purity tantalum

International Nuclear Information System (INIS)

Ishibashi, Wataru; Saito, Shinichi; Hirayama, Tooru.

1975-01-01

It is necessary to separate rare earth from tantalum by rapid methods in order to remove effects of a strong radioactivity and a short half-life. Tantalum is extracted with 10%N-lauryl (trialkylmethyl) amino-benzene pre-equilibrated with a solution of 9 M hydrochloric and 0.15 M hydrofluoric acid. A non-radioactive rare earth element is added to this aqueous solution, a precipitate of trace amounts of radioactive rare earth in aqueous solution is formed by this addition of rare earth. Some factors in the determination are: 1) the effect of the irradiation position of the sample in the atomic reactor, 2) the effect on the extraction with 10%N-lauryl (trialkylmethyl) amino-benzene for the radioactive rare earth, 3) the effect of the concentration of hydrofluoric acid, ammonia water and nitric acid on co-precipitation. As a result of the investigation we obtained the following satisfactory results: 1) Rare earth was not effected by the extraction of tantalum with 10%N-lauryl (trialkylmethyl) amino-benzene. 2) The recovery of rare earth by co-precipitation increases when an ammonium ion coexists, and when the concentration of hydrofluoric acid decreases, but the recovery decreases with the increase of nitric acid concentration. 3) The time required for the extraction is 9 hours. In case of determination for dysprosium, tantalum extracted with 10%N-lauryl (trialkylmethyl) amino-benzene before activation and the time for separation is 2 hours. (auth.)

Minimally invasive treatment of pilon fractures with a low profile plate: preliminary results in 17 cases

NARCIS (Netherlands)

Borens, Olivier; Kloen, Peter; Richmond, Jeffrey; Roederer, Goetz; Levine, David S.; Helfet, David L.

2009-01-01

To determine the results of "biologic fixation" with a minimally invasive plating technique using a newly designed low profile "Scallop" plate in the treatment of pilon fractures. Retrospective case series. A tertiary referral center. Seventeen patients were treated between 1999 and 2001 for a

Synthesis and characterization of polystyrene embolization particles doped with tantalum oxide nanoparticles for X-ray contrast.

Science.gov (United States)

Morrison, Rachel; Thompson, James; Bird, Luke; Hill, Mark A; Townley, Helen

2015-08-01

Radiopaque and fluorescent embolic particles have been synthesized and characterised to match the size of vasculature found in tumours to ensure effective occlusion of the vessels. A literature search showed that the majority of vessels surrounding a tumour were less than 50 µm and therefore polydispersed polystyrene particles with a peak size of 50 µm have been synthesised. The embolic particles contain 5-8 nm amorphous tantalum oxide nanoparticles which provide X-ray contrast. Embolic particles containing up to 9.4 wt% tantalum oxide were prepared and showed significant contrast compared to the undoped polystyrene particles. The X-ray contrast of the embolic particles was shown to be linear (R(2) = 0.9) with respect to the concentration of incorporated tantalum nanoparticles. A model was developed which showed that seventy-five 50 µm embolic particles containing 10% tantalum oxide could provide the same contrast as 5 cm of bone. Therefore, the synthesized particles would provide sufficient X-ray contrast to enable visualisation within a tumour.

Acromioclavicular joint reconstruction by coracoid process transfer augmented with hook plate.

Science.gov (United States)

Wang, Yeming; Zhang, Jianguo

2014-06-01

Various techniques have been reported for the treatment of chronic acromioclavicular (AC) joint separation. The purpose of this study was to evaluate the results of surgical construction of coracoclavicular ligament using coracoid process transfer augmented with a hook plate fixation. Twenty-one patients treated with coracoid process transfer augmented with a hook plate fixation for chronic type III and V AC injuries were retrospectively analysed in 2003-2009. The age of the patients ranged from 23 to 58 years with an average age of 41.6 years. The patients were followed up clinically and radiographically, with an average of 33.0 months. Functional status and the ability to return to work were recorded during follow-up. Constant score and visual analogue scale (VAS) for pain were measured. The mean Constant score has increased from 70.9 points preoperatively to 90.7 points at follow-up. The mean VAS score has decreased from 4.7 preoperatively to 1.2 at follow-up. The average abduction was 172°, forward flexion was 170° and external rotation was 56°. There were 10 excellent results, 10 good results and one fair result. All patients had resumed their job or returned to original sport activity at mean 3.7 months postoperatively. No reduction loss was observed after plate removal and the final follow-up. Despite retrospective nature of the study, the outcomes of surgical construction with process transfer augmented with hook plate fixation are promising for chronic type III and V AC injuries. Therapeutic level IV. Retrospective case series, treatment study. Copyright © 2014 Elsevier Ltd. All rights reserved.

Potentiometric determination of the tungsten content of tantalum-tungsten alloys with chromium II

International Nuclear Information System (INIS)

Gavra, Z.; Ronen, S.; Levin, R.

1977-05-01

A method was developed for the potentiometric determination of the tungsten content of tantalum-tungsten alloys of different compositions. These were dissolved under conditions that enabled the tungsten content to be determined with chromium (II). Phosphoric acid was selected as a suitable complexing agent for the prevention of the precipitation of tungsten and tantalum compounds. The use of chromium (II) required an oxygen-tight system and therefore the work was carried out in suitable vessels for storage and tritation

Niobium, tantalum and titanium extraction from natural and technogenic raw materials of the Kola Peninsula by liquid-liquid extraction methods

International Nuclear Information System (INIS)

Kassikova, N.I.; Kassikov, A.G.; Balabanov, Yu.I.; Petrov, V.B.; Kalinnikov, V.T.

2003-01-01

Such rare metals as niobium and tantalum are important strategic materials underlying many of the modern advanced technologies. Since the extraction and processing of rare metal concentrates from own deposits has diminished abruptly in recent years, it is essential to look into the possibility of extracting these elements from various production wastes. This work discusses liquid-liquid extraction and purification of niobium, tantalum and titanium from process solutions of loparite, perovskite and sphene concentrate decomposition with sulphuric and hydrochloric acids; niobium from lithium niobate production wastes decomposed by hydrochloric acid; and tantalum from tantalum capacitor and heat-resistant alloy wastes. (Original)

Tantalum X-ray contrast media, by M.G. Zuev and L.P. Larionov (Ekaterinburg: UrO RAN, 2002. 155 p.)

International Nuclear Information System (INIS)

Zhuravleva, E.Yu.

2004-01-01

The monograph of M.G. Zuev and L.P. Larionov Tantalum X-ray contrast media (Solid state chemistry for medicine series) is discussed. The monograph includes information on physical and chemical properties of tantalum, rare earths, and their oxides, phase compositions and phase diagrams of M 2 O 3 -Ta 2 O 5 (M - rare earths) systems is performed. Data on preclinical tests of yttrium orthotantalate and lanthanum orthotantalate as X-ray contrast media are given. Procedures for the production of X-ray contrast media involving tantalum oxide, rare earth tantalate and tantalum powder are described [ru

Minimally invasive treatment of tibial pilon fractures through arthroscopy and external fixator-assisted reduction.

Science.gov (United States)

Luo, Huasong; Chen, Liaobin; Liu, Kebin; Peng, Songming; Zhang, Jien; Yi, Yang

2016-01-01

The aim of this study was to evaluate the clinical outcome of tibial pilon fractures treated with arthroscopy and assisted reduction with an external fixator. Thirteen patients with tibial pilon fractures underwent assisted reduction for limited lower internal fixation with an external fixator under arthroscopic guidance. The weight-bearing time was decided on the basis of repeat radiography of the tibia 3 months after surgery. Postoperative ankle function was evaluated according to the Mazur scoring system. Healing of fractures was achieved in all cases, with no complications such as severe infection, skin necrosis, or an exposed plate. There were 9 excellent, 2 good, and 2 poor outcomes, scored according to the Mazur system. The acceptance rate was 85%. Arthroscopy and external fixator-assisted reduction for the minimally invasive treatment of tibial pilon fractures not only produced less trauma but also protected the soft tissues and blood supply surrounding the fractures. External fixation could indirectly provide reduction and effective operative space for arthroscopic implantation, especially for AO type B fractures and partial AO type C1 fractures.

Preparation of tantalum carbide layers on carbon using the metalliding process

Energy Technology Data Exchange (ETDEWEB)

Massot, L. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France)], E-mail: massot@chimie.ups-tlse.fr; Chamelot, P. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France); Winterton, P. [UFR Langues vivantes, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France); Taxil, P. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France)

2009-03-05

This work concerns the preparation of tantalum carbide films on carbon-based substrates using the metalliding process in LiF/NaF molten medium (60-40 mol%), containing tantalum heptafluorotantalate ions TaF{sub 7}{sup 2-}, in the 800-900 deg. C temperature range. The process uses a metalliding cell symbolised as: (+) C, TaC{sub x}/LiF-NaF-K{sub 2}TaF{sub 7}/Ta (-) involving the dissolution of Ta at the anode and the reduction of Ta ions in TaC{sub x} at the cathode. The experiments of this process were performed with different carbon substrates as cathodic material: graphite, glassy carbon and carbon braid. Samples analysis (SEM-EDS and XRD) after metalliding showed the formation of tantalum carbides (TaC and Ta{sub 2}C) at the surface of the substrate at a relatively low temperature. A kinetic study, based on the control of the cathodic reaction by the intermetallic diffusion, allowed the diffusion parameters, such as Ta/C diffusion coefficient, to be determined at several temperatures. Furthermore, the results are shown to be independent of the type of carbon substrate.

KNEE CARTILAGE AND SYNOVIAL MEMBRANE STRUCTURAL CHANGES DURING TIBIA DISTRACTION WITH PLATING

Directory of Open Access Journals (Sweden)

T. A. Stupina

2017-01-01

Full Text Available Purpose of the study — to analyze the changes in knee articular cartilage and synovial membrane during distraction external fixation of the tibia in combination with plating.Material and methods. Articular cartilage and synovial membrane of the knee joint were studied using histomorphometry methods in 9 mongrel dogs during distraction external fixation of the tibia combined with plating. Tibia and fibula osteotomies were performed at the border of middle and upper third, plate was fixed on tibia diaphysis. Lengthening was achieved at rate of 1 mm per day in four stages during 21–28 days. Animals were withdrawn from experiment in 30 and 90 days. After autopsy of knee joints the authors excised sections of synovial membrane from suprapatellar area, articular cartilage with underlying subchondral bone from loadable surface of femoral condyles. Thickness of articular cartilage, its area and volumetric density of chondrocytes was measured, proportion of chondrocytes within isogenic groups from the overall number of chondrocytes as well as proportion of empty lacunae. In synovial membrane the authors measured thickness of surface layer and numeric density of micro vessels. Articular cartilage of 5 intact animals was used as a control group.Results. After 30 days of plate fixation a hyperplasia of the integument layer, mild synovitis, and hypervascularization were observed in synovial membrane. Density of micro vessels increased to 363.93±33.71 (control group — 335.05±28.88. The authors also observed subperineural and endoneural edema as well as destruction of nerve fibers in subsynovial layer. Articular cartilage retained the zonal structure. Destructive changes were manifested by fibers separation in the superficial part of surface zone and by partial loss of chondrocytes. The following parameters were reduced: cartilage thickness, area and volumetric density of chondrocytes, proportion of isogenic groups; empty lacunae exceeded the values in

Conflict minerals from the Democratic Republic of the Congo: global tantalum processing plants, a critical part of the tantalum supply chain

Science.gov (United States)

Papp, John F.

2014-01-01

The U.S. Geological Survey (USGS) analyzes mineral and metal supply chains to identify and describe major components of mineral and metal material flows from ore extraction, through intermediate forms, to a final product. Supply chain analyses may be used (1) to identify risks to the United States associated with the supply of critical and strategic minerals and metals and (2) to provide greater supply chain transparency so that policymakers have the fact-based information needed to formulate public policy. This fact sheet focuses on the post-mining/pre-consumer-product part of the tantalum supply chain. The USGS National Minerals Information Center (NMIC) has been asked by governmental and non-governmental organizations to provide information about tantalum, tin, tungsten, and gold (collectively known as “3TG minerals”) processing facilities worldwide in response to U.S. legislation aimed at identifying and removing the supply chain links between the trade in these minerals and civil unrest in the Democratic Republic of the Congo and adjacent countries.

Niobium Nb and tantalum Ta

International Nuclear Information System (INIS)

Busev, A.I.; Tiptsova, V.G.; Ivanov, V.M.

1978-01-01

The basic methods for determining niobium and tantalum in various objects are described. Nb and Ta are separated with the aid of N-benzoyl-N-phenylhydroxylamine by precipitating Nb(5) from a tartaric acid solution with subsequent precipitation of Ta from the filtrate. The gravimetric determination of Nb and Ta in steels is based on their quantitative separation from a diluted solution by way of hydrolysis with subsequent after-precipitation with phenylarsonic acid (in the absence of W). The gravimetric determination of Nb in the presence of W is carried out with the aid of Cupferron. To determine Nb in its carbide, Nb(5) reduced to Nb(3) is titrated with a solution of K 2 Cr 2 O 7 in the presence of phenyl-anthranilic acid. The photometric determination of Nb in tungsten-containing steels and in ores containing Ti, W, Mo and Cr is based on the rhodanide method. Nb is determined in alloys with Zr and Ti photometrically with the aid of 4-(2-pyridylazo)-resorcin and in alloyed steels with the aid of benzhydroxamic acid. The latter complex is extracted with chloroform. This method is used to determine Nb in rocks. The photometric determination of Ta in TiCl 4 is carried out with the aid of pyrogallol, in commercial niobium with the aid of methyl violet, and in steel with the aid of 4-(-pyridylazo)-resorcin. Also described is the polarographic determination of Nb in tantalum pentoxide

Less invasive plate osteosynthesis in humeral shaft fractures.

Science.gov (United States)

Apivatthakakul, Theerachai; Phornphutkul, Chanakarn; Laohapoonrungsee, Anupong; Sirirungruangsarn, Yuddhasert

2009-12-01

Stable internal fixation of the humeral shaft by less invasive percutaneous plate insertion using two separate (proximal and distal) incisions, indirect reduction by closed manipulation and fixation to preserve the soft tissue and blood supply at the fracture zone. Early mobilization of the shoulder and elbow to ensure a good functional outcome. Humeral shaft fractures (classified according to AO classification as: 12-A, B, C). Humeral shaft fractures extending to the proximal or distal shaft, small or deformed medullary canal or open growth plate. Humeral shaft fractures with primary radial nerve palsy. Proximal humeral shaft fractures extending to the humeral head. Distal humeral fractures extending to the elbow joint. Two incisions proximal and distal to the fracture zone are used. A 3-cm proximal incision lies between the lateral border of the proximal part of the biceps and the medial border of the deltoid. Distally, a 3-cm incision is made along the lateral border of the biceps. The interval between biceps and brachialis is identified. The biceps is retracted medially to expose the musculocutaneous nerve. The brachialis muscle has dual innervation, the medial half being innervated by the musculocutaneous nerve and the lateral half by the radial nerve. The brachialis is split longitudinally at its midline. The musculocutaneous nerve is retracted along with the medial half of the brachialis, while the lateral half of the brachialis serves as a cushion to protect the radial nerve. A deep subbrachial tunnel is created from the distal to the proximal incision. The selected plate is tied with a suture to a hole at the tip of the tunneling instrument for pulling the plate back along the prepared track. The plate is aligned in the correct position on the anterior surface of the humerus. Traction is applied and the fracture reduced to restore alignment by image intensifier, followed by plate fixation with at least two bicortical locking screws or three bicortical

Clinical efficacy of open reduction and semirigid internal fixation in management of displaced pediatric mandibular fractures: A series of 10 cases and surgical guidelines

Directory of Open Access Journals (Sweden)

Samir Joshi

2015-01-01

Full Text Available Aim: To evaluate the efficacy of open reduction and semirigid internal fixation in the management of displaced pediatric mandibular fractures. Method: Ten patients with displaced mandibular fractures treated with 1.5 mm four holed titanium mini-plate and 4 mm screws which were removed within four month after surgery. Results: All cases showed satisfactory bone healing without any growth disturbance. Conclusion: Open reduction and rigid internal fixation (ORIF with 1.5 mm titanium mini- plates and 4 mm screws is a reliable and safe method in treatment of displaced paediatric mandibular fractures.

Clinical efficacy of open reduction and semirigid internal fixation in management of displaced pediatric mandibular fractures: a series of 10 cases and surgical guidelines.

Science.gov (United States)

Joshi, Samir; Kshirsagar, Rajesh; Mishra, Akshay; Shah, Rahul

2015-01-01

To evaluate the efficacy of open reduction and semirigid internal fixation in the management of displaced pediatric mandibular fractures. Ten patients with displaced mandibular fractures treated with 1.5 mm four holed titanium mini-plate and 4 mm screws which were removed within four month after surgery. All cases showed satisfactory bone healing without any growth disturbance. Open reduction and rigid internal fixation (ORIF) with 1.5 mm titanium mini- plates and 4 mm screws is a reliable and safe method in treatment of displaced paediatric mandibular fractures.

Case history of tantalum-weld cracking

International Nuclear Information System (INIS)

Knorovsky, G.A.

1982-01-01

Tantalum welding is normally a routine operation. Of course, the routine involves careful cleaning beforehand, and welding in an atmosphere which excludes reactive gases (O 2 , N 2 , H 2 ). Recently a weld cracking problem was encountered at SNLA despite the fact that normal precautions had been taken. This account reviews what happened, the analytical procedures followed to determine the unusual source of the problem, and the remedy which solved the problem

Hot tungsten plate based ionizer for cesium plasma in a multi-cusp field experiment

International Nuclear Information System (INIS)

Patel, Amitkumar D.; Sharma, Meenakshee; Ramasubramanian, Narayanan; Chattopadhyay, Prabal K.

2015-01-01

In a newly proposed basic experiment, contact-ionized cesium ions will be confined by a multi cups magnetic field configuration. The cesium ion will be produced by impinging collimated neutral atoms on an ionizer consisting of the hot tungsten plate. The temperature of the tungsten plate will also be made high enough (∼2700 K) such that it will contribute electrons also to the plasma. It is expected that at this configuration the cesium plasma would be really quiescent and would be free from even the normal drift waves observed in the classical Q-machines. For the ionizer a design based on F. F. Chen's design was made. This ionizer is very fine machining and exotic material like Tungsten plate, Molybdenum screws, rings, and Boron Nitride ceramics etc. The fine and careful machining of these materials was very hard. In this paper, the experience about to join the tungsten wire to molybdenum plate and alloy of tantalum and molybdenum ring is described. In addition experimental investigations have been made to measure 2D temperature distribution profile of the Tungsten hot plate using infrared camera and the uniformity of temperature distribution over the hot plate surface is discussed. (author)

A novel tantalum-based sol-gel packed microextraction syringe for highly specific enrichment of phosphopeptides in MALDI-MS applications.

Science.gov (United States)

Çelikbıçak, Ömür; Atakay, Mehmet; Güler, Ülkü; Salih, Bekir

2013-08-07

A new tantalum-based sol-gel material was synthesized using a unique sol-gel synthesis pathway by PEG incorporation into the sol-gel structure without performing a calcination step. This improved its chemical and physical properties for the high capacity and selective enrichment of phosphopeptides from protein digests in complex biological media. The specificity of the tantalum-based sol-gel material for phosphopeptides was evaluated and compared with tantalum(V) oxide (Ta2O5) in different phosphopeptide enrichment applications. The tantalum-based sol-gel and tantalum(V) oxide were characterized in detail using FT-IR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM), and also using a surface area and pore size analyzer. In the characterization studies, the surface morphology, pore volume, crystallinity of the materials and PEG incorporation into the sol-gel structure to produce a more hydrophilic material were successfully demonstrated. The X-ray diffractograms of the two different materials were compared and it was noted that the broad signals of the tantalum-based sol-gel clearly represented the amorphous structure of the sol-gel material, which was more likely to create enough surface area and to provide more accessible tantalum atoms for phosphopeptides to be easily adsorbed when compared with the neat and more crystalline structure of Ta2O5. Therefore, the phosphopeptide enrichment performance of the tantalum-based sol-gels was found to be remarkably higher than the more crystalline Ta2O5 in our studies. Phosphopeptides at femtomole levels could be selectively enriched using the tantalum-based sol-gel and detected with a higher signal-to-noise ratio by matrix-assisted laser desorption/ionization-mass spectrometer (MALDI-MS). Moreover, phosphopeptides in a tryptic digest of non-fat bovine milk as a complex real-world biological sample were retained with higher yield using a tantalum-based sol-gel. Additionally, the sol-gel material

Intractable Chronic Low-Back Pain Caused by Ligamentopathia Treated Using a Spinous Process Plate (S-plate

Directory of Open Access Journals (Sweden)

Yu-ichiro Ohnishi

2010-03-01

Full Text Available We report a case of intractable chronic low-back pain in a gymnast that was caused by ligamentopathia in the interspinous region of the lumbar vertebrae. Sprained interspinous ligaments are a common mechanical cause of acute low-back pain in athletes. Although conservative therapy is generally effective in such cases, in this case it was not. The patient experienced severe low-back pain during lumbar flexion with tension between the L5/S interspinous ligaments. We performed interspinous fixation by using a spinous process plate system, which has been developed for short in situ fusions, and following which the low-back pain resolved. Conservative therapy for low-back pain caused by ligamentopathia is first-line choice, but interspinous fixation with instrumentation might be recommended in intractable cases with conservative therapy.

Hot pressing of nanocrystalline tantalum using high frequency induction heating and pulse plasma sintering

Science.gov (United States)

Jakubowicz, J.; Adamek, G.; Sopata, M.; Koper, J. K.; Siwak, P.

2017-12-01

The paper presents the results of nanocrystalline powder tantalum consolidation using hot pressing. The authors used two different heating techniques during hot pressing: high-frequency induction heating (HFIH) and pulse plasma sintering (PPS). A comparison of the structure, microstructure, mechanical properties and corrosion resistance of the bulk nanocrystalline tantalum obtained in both techniques was performed. The nanocrystalline powder was made to start from the microcrystalline one using the high-energy ball milling process. The nanocrystalline powder was hot-pressed at 1000 °C, whereas, for comparison, the microcrystalline powder was hot pressed up to 1500 °C for proper consolidation. The authors found that during hot pressing, the powder partially reacts with the graphite die covered by boron nitride, which facilitated punches and powder displacement in the die during densification. Tantalum carbide and boride in the nanocrystalline material was found, which can improve the mechanical properties. The hardness of the HFIH and PPS nanocrystalline tantalum was as high as 625 and 615 HV, respectively. The microstructure was more uniform in the PPS nanomaterial. The corrosion resistance in both cases deteriorated, in comparison to the microcrystalline material, while the PPS material corrosion resistance was slightly better than that of the HFIH one.

Functional Outcomes After Temporary Bridging With Locking Plates in Lisfranc Injuries

NARCIS (Netherlands)

van Koperen, Paul J.; de Jong, Vincent M.; Luitse, Jan S. K.; Schepers, Tim

2016-01-01

The standard operative treatment of Lisfranc fracture dislocations currently consists of open reduction and transarticular fixation. Recently, bridge plating has been used more often. Using joint spanning, the reduced fracture dislocation is temporary stabilized to minimize articular damage. The

Comparison of Neck Screw and Conventional Fixation Techniques in Mandibular Condyle Fractures Using 3-Dimensional Finite Element Analysis.

Science.gov (United States)

Conci, Ricardo Augusto; Tomazi, Flavio Henrique Silveira; Noritomi, Pedro Yoshito; da Silva, Jorge Vicente Lopes; Fritscher, Guilherme Genehr; Heitz, Claiton

2015-07-01

To compare the mechanical stress on the mandibular condyle after the reduction and fixation of mandibular condylar fractures using the neck screw and 2 other conventional techniques according to 3-dimensional finite element analysis. A 3-dimensional finite element model of a mandible was created and graphically simulated on a computer screen. The model was fixed with 3 different techniques: a 2.0-mm plate with 4 screws, 2 plates (1 1.5-mm plate and 1 2.0-mm plate) with 4 screws, and a neck screw. Loads were applied that simulated muscular action, with restrictions of the upper movements of the mandible, differentiation of the cortical and medullary bone, and the virtual "folds" of the plates and screws so that they could adjust to the condylar surface. Afterward, the data were exported for graphic visualization of the results and quantitative analysis was performed. The 2-plate technique exhibited better stability in regard to displacement of fractures, deformity of the synthesis materials, and minimum and maximum tension values. The results with the neck screw were satisfactory and were similar to those found when a miniplate was used. Although the study shows that 2 isolated plates yielded better results compared with the other groups using other fixation systems and methods, the neck screw could be an option for condylar fracture reduction. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Cobalt and tantalum tracers measured by activation analysis in sediment transport studies

Energy Technology Data Exchange (ETDEWEB)

Groot, A.J. de [Institute for Soil Fertility, Haren (Netherlands); Allersma, E [Delft Hydraulics Laboratory, Delft (Netherlands); Bruin, M de; Houtman, J P.W. [Reactor Institute, Delft (Netherlands)

1970-09-15

The paper proposes certain principles of research to be used in investigating the origin and transport of fine-grained sediments in rivers and sea arms in connection with siltation problems of harbours and navigation channels. An element, which either does not occur in the sediment or only occurs in minute quantities, is fixed to the mud from the river or sea arm. After the material is marked it is returned to the water course where it mixes with the solids moving naturally. At specified points throughout the water course sediment samples are taken to determine the marking element by activation analysis. This gives an insight into the flow path of the suspended matter. The selection and successful application of tracers that can be measured by activation analysis depends on the sensitivity of detection, the natural occurrence of the relevant elements in the sediments under investigation and the fixation capacity of the tracer to the various grain size fractions. Further, the influence of the added element on the sedimentation behaviour of the mud in suspension and on the desorption properties must be considered. The irradiation of Co and Ta with thermal neutrons gives rise to a very sensitive evaluation of the original elements present. The fixation process of Co is restricted to sediments with special characteristics; Ta, however, can adhere tightly to any sediment. Tantalum also has the advantage that its natural content in sediments is very low. Large quantities (several per cent by weight) can adhere to the sediment without changing the sedimentation properties to an appreciable extent. Hardly any losses occur during leaching experiments simulating natural conditions. A detailed treatment is given of the chemical aspects of the method, including the behaviour of the elements used in the light of the general environmental processes of sediment constituents in deltaic systems. Finally, the scope and limits of the method are discussed. (author)

Cobalt and Tantalum Tracers Measured by Activation Analysis in Sediment Transport Studies

Energy Technology Data Exchange (ETDEWEB)

Groot, A.J. de [Institute for Soil Fertility, Haren (Netherlands); Allersma, E. [Delft Hydraulics Laboratory, Delft (Netherlands); Bruin, M. de; Houtman, J. P.W. [Reactor Institute, Delft (Netherlands)

1970-09-15

The paper proposes certain principles of research to be used in investigating the origin and transport of fine-grained sediments in rivers and sea arms in connection with siltation problems of harbours and navigation channels. An element, which either does not occur in the sediment or only occurs in minute quantities, is fixed to the mud from the river or sea arm. After the material is marked it is returned to the water course where it mixes with the solids moving naturally. At specified points throughout the water course sediment samples are taken to determine the marking element by activation analysis. This gives an insight into the flow path of the suspended matter. The selection and successful application of tracers that can be measured by activation analysis depends on the sensitivity of detection, the natural occurrence of the relevant elements in the sediments under investigation and the fixation capacity of the tracer to the various grain size fractions. Further, the influence of the added element on the sedimentation behaviour of the mud in suspension and on the desorption properties must be considered. The irradiation of Co and Ta with thermal neutrons gives rise to a very sensitive evaluation of the original elements present. The fixation process of Co is restricted to sediments with special characteristics; Ta, however, can adhere tightly to any sediment. Tantalum also has the advantage that its natural content in sediments is very low. Large quantities (several per cent by weight) can adhere to the sediment without changing the sedimentation properties to an appreciable extent. Hardly any losses occur during leaching experiments simulating natural conditions. A detailed treatment is given of the chemical aspects of the method, including the behaviour of the elements used in the light of the general environmental processes of sediment constituents in deltaic systems. Finally, the scope and limits of the method are discussed. (author)

Functional Recovery Following Pertrochanteric Hip Fractures Fixated with the Dynamic Hip Screw vs. the Percutaneous Compression Plate

Directory of Open Access Journals (Sweden)

Yocheved Laufer

2005-01-01

Full Text Available The Dynamic Hip Screw (DHS is currently the most frequently used implant for the treatment of pertrochanteric hip fractures. The Percutaneous Compression Plate (PCCP is a recently developed, alternative device that involves minimal invasive surgery. The objective of the present study was to compare functional recovery following these two surgical procedures. A total of 76 consecutive elderly subjects (mean age and standard deviation, 80.6 ± 5.5 following pertrochanteric hip fracture fixation were evaluated prospectively. Functional recovery was assessed 3 and 12 weeks and 2 years following surgery. Differences between groups 3 weeks postsurgery were found only in pain level during ambulation and in the weight-bearing capability of the operated extremity, which were both in favor of the PCCP. By 3 months, both groups had improved in all measures, but did not reach their preinjury level of independence. However, the PCCP group ambulated with fewer assistive devices and demonstrated better recovery of basic activities of daily living (BADL. While the majority of the subjects from both groups ambulated independently 2 years postsurgery, the PCCP group exhibited less pain during ambulation, was more independent in ADL, and required fewer assistive devices for ambulation. To summarize, the PCCP presents enhanced short- and long-term recovery of functional abilities in comparison to DHS. However, given the limited number of patients, further studies are necessary to substantiate these results.

IER-297 CED-2: Final Design for Thermal/Epithermal eXperiments with Jemima Plates with Polyethylene and Hafnium

Energy Technology Data Exchange (ETDEWEB)

Nelson, A. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Percher, C. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zywiec, W. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Heinrichs, D. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2018-01-11

This report presents the final design (CED-2) for IER-297, and focuses on 15 critical configurations using highly enriched uranium (HEU) Jemima plates moderated by polyethylene with and without hafnium diluent. The goal of the U.S. Nuclear Criticality Safety Program’s Thermal/Epithermal eXperiments (TEX) is to design and conduct new critical experiments to address high priority nuclear data needs from the nuclear criticality safety and nuclear data communities, with special emphasis on intermediate energy (0.625 eV – 100 keV) assemblies that can be easily modified to include various high priority diluent materials. The TEX (IER 184) CED-1 Report [1], completed in 2012, demonstrated the feasibility of meeting the TEX goals with two existing NCSP fissile assets, plutonium Zero Power Physics Reactor (ZPPR) plates and highly enriched uranium (HEU) Jemima plates. The first set of TEX experiments will focus on using the plutonium ZPPR plates with polyethylene moderator and tantalum diluents.

TiO2 effect on break-down of low-grade tantalum-niobium concentrates in the process of sulphatization

International Nuclear Information System (INIS)

Petrova, N.V.; Popov, A.D.; Mulenko, V.N.

1982-01-01

The effect of TiO 2 additive or materials containing it on tantalum-niobate decomposition in the process of sulphatization is investigated. It is shown that favourable effect of titanium dioxide in the process of sulphatization is especially noticeable in reprocessing of hard-brokening down tantalum-niobium concentrates with low Nb:Ta ratio etc. Chemical composition and type of tantalum-niobium mineralization of enrichment products used in the given investigation is presented. It is stated that the degree of concentrate break-down under similar sulphatization conditions (t=230 deg C; tau=2 h) essentially depends on the quantity of the introduced titanium dioxide. It is shown that sulphatization in the presence of titanium dioxide additive or materials containing it permits to exercise practically complete break-down of lean tantalum-niobium raw material, to avoid application of complexers in leaching of sulphatization products

[Conventional plate osteosynthesis].

Science.gov (United States)

Klaue, K

2010-02-01

Consolidation of bone is an essential clinical problem when treating fractures, fixing osteotomies and fusing joints. In most cases, the means of fixation are plates and screws. The goal is functional postoperative therapy by moving the adjacent joints and thus avoiding the deleterious disadvantages of long-lasting articular immobilization. Pre-operative planning, surgical approach, a good understanding of the precise mechanics of the structure and the biological answer for the various tissues are prerequisites of successful osteosynthesis. The choice of implants and the application of their versatility, as well as their adaptation to individual cases are the key to good results.

Electron microprobe analysis of tantalum--nitride thin films

International Nuclear Information System (INIS)

Stoltz, D.L.; Starkey, J.P.

1979-06-01

Quantitative chemical analysis of 500- and 2000-angstrom tantalum--nitride films on glass substrates has been accomplished using an electron microprobe x-ray analyzer. In order to achieve this analysis, modifications to the microprobe were necessary. A description of the calibration procedure, the method of analysis, and the quantitative results are discussed

Poisoning Experiments Aimed at Discriminating Active and Less-Active Sites of Silica-Supported Tantalum Hydride for Alkane Metathesis

KAUST Repository

Saggio, Guillaume; Taoufik, Mostafa; Basset, Jean-Marie; Thivolle-Cazat, Jean

2010-01-01

Only 50% of the silica-supported tantalum hydride sites are active in the metathesis of propane. Indeed, more than 45% of the tantalum hydride can be eliminated by a selective oxygen poisoning of inactive sites with no significant decrease

Corrosion resistance of high-performance materials titanium, tantalum, zirconium

CERN Document Server

2012-01-01

Corrosion resistance is the property of a material to resist corrosion attack in a particular aggressive environment. Although titanium, tantalum and zirconium are not noble metals, they are the best choice whenever high corrosion resistance is required. The exceptionally good corrosion resistance of these high–performance metals and their alloys results from the formation of a very stable, dense, highly adherent, and self–healing protective oxide film on the metal surface. This naturally occurring oxide layer prevents chemical attack of the underlying metal surface. This behavior also means, however, that high corrosion resistance can be expected only under neutral or oxidizing conditions. Under reducing conditions, a lower resistance must be reckoned with. Only very few inorganic and organic substances are able to attack titanium, tantalum or zirconium at ambient temperature. As the extraordinary corrosion resistance is coupled with an excellent formability and weldability these materials are very valua...

Rapid maxillary distraction protocol utilizing the halo distraction system and rigid internal fixation.

Science.gov (United States)

Baker, Stephen B; Reid, Russell R; Burkey, Brooke; Bartlett, Scott P

2007-09-01

To shorten head frame wear time associated with external halo distraction (HD), we have adapted a protocol for maxillary distraction with the halo system that integrates plate fixation. All patients had a history of cleft lip and/or palate and maxillary retrusion > or = 8 mm. Five patients treated with this protocol and followed for at least 1 year were included in this study. The protocol included a 3-day latency period, variable maxillary distraction, and removal of the halo device with simultaneous rigid internal fixation. Two patients had a variable period of maxillomandibular fixation (MMF), which maintained the maxillary advancement and idealized intercuspal position while permitting further callus maturation. Cephalographs were obtained preoperatively, immediately following distractor removal, and 1 year after rigid internal fixation. The mean age at time of surgery was 18.7 years. The maxillary deficiency ranged from 8 to 15 mm (mean = 10.6 mm). All five patients demonstrated excellent occlusion. Cephalometric analysis 1-year post rigid internal fixation revealed minimal (maxillary distraction followed by MMF to maintain maxillary advancement may reduce halo device wear to 1 to 2 weeks. MMF optimizes occlusion by forcing the maxillary teeth into maximal intercuspal position. Rigid fixation is not only associated with less long-term relapse compared to nonrigid forms of fixation, but also minimizes the incidence of nonunion. This treatment protocol provides the advancement possible with distraction osteogenesis and the accuracy of orthognathic surgery, thereby minimizing external head frame wear.

Technological challenges in extractive metallurgy and refining of niobium, tantalum and preparation of their alloys

International Nuclear Information System (INIS)

Mirji, K.V.; Sheela; Saibaba, N.

2016-01-01

Manufacturing of refractory and reactive metals, their alloys and fabricated products has been always difficult due to their high affinity with atmospheric gases, stringent specifications and exhaustive quality requirements. In the field of development of these materials, Nuclear Fuel Complex (NFC), Hyderabad has been at the fore front in accepting the challenges for the advancement of technological growth. Extensive developments have been carried out during the last few decades in the field of niobium, tantalum, zirconium etc in the form of pure metal, their compounds and alloys. Over the period of time, efforts have been made for developing sophisticated facilities along with trained man power for manufacturing of critical items for which technical knowhow is not available either with private industries or any other organizations in the country. In the field of reactive metals, though general theory is well established, production is intriguing and requires expert handling on the field. At NFC, efforts were put towards industrial adoptability of the useful knowledge gained from lab scale to reliable production scale. Comprehensive study was conducted to systematically study the effects of various process parameters starting from ore to the metals and their alloys, equipment were modified for ease of operation with stress on recycling/reusing of the waste and handling of effluents. However scale of operation and therefore cost of production has been matter of concern in the field of tantalum and niobium. Electron beam refining is used for production of highly pure reactive and refractory metals like tantalum, niobium, zirconium etc. and their alloys under high vacuum. Special Materials Plant (SMP) at Nuclear Fuel Complex, Hyderabad has developed processes for production of niobium oxide, tantalum oxide, tantalum metal powder, tantalum anodes/capacitors, potassium tantalum fluoride, Nb thermit, Nb metal granules, RRR grade niobium, Nb base alloys such as Zr

Biomechanical optimization of different fixation modes for a proximal femoral L-osteotomy

Directory of Open Access Journals (Sweden)

Chen Hsih-Hao

2009-09-01

Full Text Available Abstract Background Numerous proposed surgical techniques have had minimal success in managing greater trochanter overgrowth secondary to retarded growth of the femoral capital epiphysis. For reconstruction of residual hip deformities, a novel type of proximal femur L-osteotomy was performed with satisfactory results. Although the clinical outcome was good, the biomechanical characteristics of the femur after such an osteotomy have not been clearly elucidated. Therefore, this study presents a three dimensional finite element analysis designed to understand the mechanical characteristics of the femur after the L-osteotomy. Methods A patient with left hip dysplasia was recruited as the study model for L-osteotomy. The normal right hip was used as a reference for performing the corrective surgery. Four FEA models were constructed using different numbers of fixation screws but the same osteotomy lengths together with four FEA models with the same number of fixation screws but different osteotomy lengths. The von Mises stress distributions and femoral head displacements were analyzed and compared. Results The results revealed the following: 1. The fixation devices (plate and screws sustained most of the external loading, and the peak value of von Mises stress on the fixation screws decreased with an increasing number of screws. 2. Additional screws are more beneficial on the proximal segment than on the distal segment for improving the stability of the postoperative femur. 3. The extent of osteotomy should be limited because local stress might be concentrated in the femoral neck region with increasing length of the L-osteotomy. Conclusion Additional screw placement on the proximal segment improves stability in the postoperative femur. The cobra-type plate with additional screw holes in the proximal area might improve the effectiveness of L-osteotomies.

Use of a Tantalum Liner to Reduce Bore Erosion and Increase Muzzle Velocity in Two-Stage Light Gas Guns

Science.gov (United States)

Bogdanoff, David W.

2015-01-01

Muzzle velocities and gun erosion predicted by earlier numerical simulations of two stage light gas guns with steel gun tubes were in good agreement with experimental values. In a subsequent study, simulations of high performance shots were repeated with rhenium (Re) gun tubes. Large increases in muzzle velocity (2 - 4 km/sec) were predicted for Re tubes. In addition, the hydrogen-produced gun tube erosion was, in general, predicted to be zero with Re tubes. Tantalum (Ta) has some mechanical properties superior to those of Re. Tantalum has a lower modulus of elasticity than Re for better force transmission from the refractory metal liner to an underlying thick wall steel tube. Tantalum also has greater ductility than Re for better survivability during severe stress/strain cycles. Also, tantalum has been used as a coating or liner in military powder guns with encouraging results. Tantalum has, however, somewhat inferior thermal properties to those of rhenium, with a lower melting point and lower density and thermal conductivity. The present study was undertaken to see to what degree the muzzle velocity gains of rhenium gun tubes (over steel tubes) could be achieved with tantalum gun tubes. Nine high performance shots were modeled with a new version of our CFD gun code for steel, rhenium and tantalum gun tubes. For all except the highest velocity shot, the results with Ta tubes were nearly identical with those for Re tubes. Even for the highest velocity shot, the muzzle velocity gain over a steel tube using Ta was 82% of the gain obtained using Re. Thus, the somewhat inferior thermal properties of Ta (when compared to those of Re) translate into only very slightly poorer overall muzzle velocity performance. When this fact is combined with the superior mechanical properties of Ta and the encouraging performance of Ta liners/coatings in military powder guns, tantalum is to be preferred over Re as a liner/coating material for two stage light gas guns to increase muzzle

Evaluation of Ferrite Chip Beads as Surge Current Limiters in Circuits with Tantalum Capacitors

Science.gov (United States)

Teverovsky, Alexander

2014-01-01

Limiting resistors are currently required to be connected in series with tantalum capacitors to reduce the risk of surge current failures. However, application of limiting resistors decreases substantially the efficiency of the power supply systems. An ideal surge current limiting device should have a negligible resistance for DC currents and high resistance at frequencies corresponding to transients in tantalum capacitors. This work evaluates the possibility of using chip ferrite beads (FB) as such devices. Twelve types of small size FBs from three manufacturers were used to evaluate their robustness under soldering stresses and at high surge current spikes associated with transients in tantalum capacitors. Results show that FBs are capable to withstand current pulses that are substantially greater than the specified current limits. However, due to a sharp decrease of impedance with current, FBs do not reduce surge currents to the required level that can be achieved with regular resistors.

Surface chemistry and cytotoxicity of reactively sputtered tantalum oxide films on NiTi plates

Energy Technology Data Exchange (ETDEWEB)

McNamara, K. [Materials and Surface Science Institute, University of Limerick, Limerick (Ireland); Department of Physics & Energy, University of Limerick, Limerick (Ireland); Kolaj-Robin, O.; Belochapkine, S.; Laffir, F. [Materials and Surface Science Institute, University of Limerick, Limerick (Ireland); Gandhi, A.A. [Materials and Surface Science Institute, University of Limerick, Limerick (Ireland); Department of Physics & Energy, University of Limerick, Limerick (Ireland); Tofail, S.A.M., E-mail: tofail.syed@ul.ie [Materials and Surface Science Institute, University of Limerick, Limerick (Ireland); Department of Physics & Energy, University of Limerick, Limerick (Ireland)

2015-08-31

NiTi, an equiatomic alloy containing nickel and titanium, exhibits unique properties such as shape memory effect and superelasticity. NiTi also forms a spontaneous protective titanium dioxide (TiO{sub 2}) layer that allows its use in biomedical applications. Despite the widely perceived biocompatibility there remain some concerns about the sustainability of the alloy's biocompatibility due to the defects in the TiO{sub 2} protective layer and the presence of high amount of sub-surface Ni, which can give allergic reactions. Many surface treatments have been investigated to try to improve both the corrosion resistance and biocompatibility of this layer. For such purposes, we have sputter deposited tantalum (Ta) oxide thin films onto the surface of the NiTi alloy. Despite being one of the promising metals for biomedical applications, Ta, and its various oxides and their interactions with cells have received relatively less attention. The oxidation chemistry, crystal structure, morphology and biocompatibility of these films have been investigated. In general, reactive sputtering especially in the presence of a low oxygen mixture yields a thicker film with better control of the film quality. The sputtering power influenced the surface oxidation states of Ta. Both microscopic and quantitative cytotoxicity measurements show that Ta films on NiTi are biocompatible with little to no variation in cytotoxic response when the surface oxidation state of Ta changes. - Highlights: • Reactive sputtering in low oxygen mixture yields thicker better quality films. • Sputtering power influenced surface oxidation states of Ta. • Cytotoxicity measurements show Ta films on NiTi are biocompatible. • Little to no variation in cytotoxic response when oxidation state changes.

Radiographic examination of tracheal strictures by means of powdered tantalum

International Nuclear Information System (INIS)

Scheel, W.; Dippmann, A.

1979-01-01

This report deals with the diagnostic value of a tracheobronchography with powdered tantalum in 5 patients who suffer from a severe stricture of the trachea. The own experiences with this method are described. (orig.) [de

Tantalum Nitride Electron-Selective Contact for Crystalline Silicon Solar Cells

KAUST Repository

Yang, Xinbo; Aydin, Erkan; Xu, Hang; Kang, Jingxuan; Hedhili, Mohamed N.; Liu, Wenzhu; Wan, Yimao; Peng, Jun; Samundsett, Christian; Cuevas, Andres; De Wolf, Stefaan

2018-01-01

novel electron‐selective, passivating contact for c‐Si solar cells is presented. Tantalum nitride (TaN x ) thin films deposited by atomic layer deposition are demonstrated to provide excellent electron‐transporting and hole‐blocking properties

Twinning anisotropy of tantalum during nanoindentation

Energy Technology Data Exchange (ETDEWEB)

Goel, Saurav, E-mail: S.GOEL@qub.ac.uk [School of Mechanical and Aerospace Engineering, Queen' s University, Belfast, BT9 5AH (United Kingdom); Beake, Ben [Micro Materials Limited, Willow House, Yale Business Village, Ellice Way, Wrexham LL13 7YL (United Kingdom); Dalton Research Institute, Manchester Metropolitan University, Manchester, M15GD (United Kingdom); Chan, Chi-Wai [School of Mechanical and Aerospace Engineering, Queen' s University, Belfast, BT9 5AH (United Kingdom); Haque Faisal, Nadimul [School of Engineering, Robert Gordon University, Garthdee Road, Aberdeen AB10 7GJ (United Kingdom); Dunne, Nicholas [School of Mechanical and Aerospace Engineering, Queen' s University, Belfast, BT9 5AH (United Kingdom)

2015-03-11

Unlike other BCC metals, the plastic deformation of nanocrystalline Tantalum (Ta) during compression is regulated by deformation twinning. Whether or not this twinning exhibits anisotropy was investigated through simulation of displacement-controlled nanoindentation test using molecular dynamics (MD) simulation. MD data was found to correlate well with the experimental data in terms of surface topography and hardness measurements. The mechanism of the transport of material was identified due to the formation and motion of prismatic dislocations loops (edge dislocations) belonging to the 1/2〈111〉 type and 〈100〉 type Burgers vector family. Further analysis of crystal defects using a fully automated dislocation extraction algorithm (DXA) illuminated formation and migration of twin boundaries on the (110) and (111) orientation but not on the (010) orientation and most importantly after retraction all the dislocations disappeared on the (110) orientation suggesting twinning to dominate dislocation nucleation in driving plasticity in tantalum. A significant finding was that the maximum shear stress (critical Tresca stress) in the deformation zone exceeded the theoretical shear strength of Ta (Shear modulus/2π~10.03 GPa) on the (010) orientation but was lower than it on the (110) and the (111) orientations. In light of this, the conventional lore of assuming the maximum shear stress being 0.465 times the mean contact pressure was found to break down at atomic scale.

The physicochemical/biological properties of porous tantalum and the potential surface modification techniques to improve its clinical application in dental implantology

Energy Technology Data Exchange (ETDEWEB)

Liu, Yindong [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu (China); Bao, Chongyun, E-mail: cybao9933@scu.edu.cn [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu (China); Wismeijer, Daniel [Department of Oral Implantology and Prosthetic Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute Amsterdam, VU University Amsterdam and University of Amsterdam, Amsterdam (Netherlands); Wu, Gang, E-mail: g.wu@acta.nl [Department of Oral Implantology and Prosthetic Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute Amsterdam, VU University Amsterdam and University of Amsterdam, Amsterdam (Netherlands)

2015-04-01

More rapid restoration and more rigid functionality have been pursued for decades in the field of dental implantology. Under such motivation, porous tantalum has been recently introduced to design a novel type of dental implant. Porous tantalum bears interconnected porous structure with pore size ranging from 300 to 600 μm and a porosity of 75–85%. Its elastic modulus (1.3–10 GPa) more closely approximates that of natural cortical (12–18 GPa) and cancellous bone (0.1–0.5 GPa) in comparison with the most commonly used dental materials, such as titanium and titanium alloy (106–115 GPa). Porous tantalum is highly corrosion-resistant and biocompatible. It can significantly enhance the proliferation and differentiation of primary osteoblasts derived from elderly people than titanium. Porous tantalum can allow bone ingrowth and establish not only osseointegration but also osseoincorporation, which will significantly enhance the secondary stability of implants in bone tissue. In this review, we summarize the physicochemical, mechanical and biological properties of porous tantalum. We further discuss the performance of current tantalum dental implants and present the methodologies of surface modifications in order to improve their biological performance.

The physicochemical/biological properties of porous tantalum and the potential surface modification techniques to improve its clinical application in dental implantology

International Nuclear Information System (INIS)

Liu, Yindong; Bao, Chongyun; Wismeijer, Daniel; Wu, Gang

2015-01-01

More rapid restoration and more rigid functionality have been pursued for decades in the field of dental implantology. Under such motivation, porous tantalum has been recently introduced to design a novel type of dental implant. Porous tantalum bears interconnected porous structure with pore size ranging from 300 to 600 μm and a porosity of 75–85%. Its elastic modulus (1.3–10 GPa) more closely approximates that of natural cortical (12–18 GPa) and cancellous bone (0.1–0.5 GPa) in comparison with the most commonly used dental materials, such as titanium and titanium alloy (106–115 GPa). Porous tantalum is highly corrosion-resistant and biocompatible. It can significantly enhance the proliferation and differentiation of primary osteoblasts derived from elderly people than titanium. Porous tantalum can allow bone ingrowth and establish not only osseointegration but also osseoincorporation, which will significantly enhance the secondary stability of implants in bone tissue. In this review, we summarize the physicochemical, mechanical and biological properties of porous tantalum. We further discuss the performance of current tantalum dental implants and present the methodologies of surface modifications in order to improve their biological performance

Micro/Nano Structural Tantalum Coating for Enhanced Osteogenic Differentiation of Human Bone Marrow Stem Cells

OpenAIRE

Ding Ding; Youtao Xie; Kai Li; Liping Huang; Xuebin Zheng

2018-01-01

Recently, tantalum has been attracting much attention for its anticorrosion resistance and biocompatibility, and it has been widely used in surface modification for implant applications. To improve its osteogenic differentiation of human bone marrow stem cells (hBMSCs), a micro/nano structure has been fabricated on the tantalum coating surface through the combination of anodic oxidation and plasma spraying method. The morphology, composition, and microstructure of the modified coating were co...

Spark plasma sintering of tantalum carbide

International Nuclear Information System (INIS)

Khaleghi, Evan; Lin, Yen-Shan; Meyers, Marc A.; Olevsky, Eugene A.

2010-01-01

A tantalum carbide powder was consolidated by spark plasma sintering. The specimens were processed under various temperature and pressure conditions and characterized in terms of relative density, grain size, rupture strength and hardness. The results are compared to hot pressing conducted under similar settings. It is shown that high densification is accompanied by substantial grain growth. Carbon nanotubes were added to mitigate grain growth; however, while increasing specimens' rupture strength and final density, they had little effect on grain growth.

Delayed Esophageal Pseudodiverticulum after Anterior Cervical Spine Fixation: Report of 2 Cases

Directory of Open Access Journals (Sweden)

Ali Sadrizadeh

2015-03-01

Full Text Available Introduction: Although perforation of the esophagus, in the anterior cervical spine fixation, is well established, cases with delayed onset, especially cases that present pseudodiverticulum, are not common. In addition, management of the perforation in this situation is debated.  Case Report:   Delayed esophageal pseudodiverticulum was managed in two patients with a history of anterior spine fixation. Patients were operated on, the loose plate and screws were extracted, the wall of the diverticulum was excised, the perforation on the nasogastric tube was suboptimally repaired, and a closed suction drain was placed there. The NGT was removed on the 7th day and barium swallow demonstrated no leakage at the operation site; therefore, oral feeding was started without any problem.  Conclusion:  In cases with delayed perforation, fistula, or diverticulum removal of anterior fixation instruments, gentle repair of the esophageal wall without persistence on definitive and optimal perforation closure, wide local drainage, early enteral nutrition via NGT, and antibiotic prescription is suggested.

Plasma-sprayed tantalum/alumina cermets

International Nuclear Information System (INIS)

Kramer, C.M.

1977-12-01

Cermets of tantalum and alumina were fabricated by plasma spraying, with the amount of alumina varied from 0 to 65 percent (by volume). Each of four compositions was then measured for tensile strength, elastic modulus, and coefficient of thermal expansion. In general, strength and strain to failure decreased with increasing alumina content: 62 MPa for 100 percent Ta to 19 MPa for 35 v percent Ta. A maximum of 0.1 percent strain was observed for the sprayed 100 percent Ta specimens. The coefficient of thermal expansion measured for the pure Ta was 6.2 (10 -6 )/K

Partial molar volumes of hydrogen and deuterium in niobium, vanadium, and tantalum

International Nuclear Information System (INIS)

Peterson, D.T.; Herro, H.M.

1983-01-01

The partial molar volumes of hydrogen and deuterium were measured in vanadium, niobium, and tantalum by a differential pressure technique. One-half of an electrolytically charged sample plat was compressed between hardened steel blocks in a hydraulic press. The activity of hydrogen in the hig pressure region was raised and caused hydrogen to diffuse into the low pressure region. The partia molar volume was calculated from the ratio of the hydrogen concentrations in the high and low pressure regions of the sample. Small isotope effects were found in the partial molar volume. Hydrogen had the larger volume in niobium and tantalum, but the reverse was true in vanadium

Tin(2) difluoride and antimony(3) trifluoride as fluorine donors in reactions with tantalum halides in various solvents

International Nuclear Information System (INIS)

Kokunov, Yu.V.; Ershova, M.M.; Razgonyaeva, G.A.; Buslaev, Yu.A.

2001-01-01

The reactions of SnF 2 , SbF 3 with TaF 5 and TaCl 5 in acetonitrile and dimethylsulfoxide were studied by means of 19 F and 119 Sn NMR. SnF 2 and SbF 3 were established to be donors of fluorine ions for the tantalum(5). It was found that the anion and cation tantalum fluorochloride complexes were formed in acetonitrile, and [TaF 6 ] - was dominated in dimethylsulfoxide. In the solution the tin(2) is present as fluorine-containing polymer cations. Dimethylsulfoxide, as distinct from acetonitrile, leads to disproportionation of tantalum fluorochlorides [ru

Redox Chemisty of Tantalum Clusters on Silica Characterized by X-ray Absorption Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Nemana,S.; Gates, B.

2006-01-01

SiO{sub 2}-supported clusters of tantalum were synthesized from adsorbed Ta(CH{sub 2}Ph){sub 5} by treatment in H{sub 2} at 523 K. The surface species were characterized by X-ray absorption spectroscopy (extended X-ray absorption fine structure (EXAFS) spectroscopy and X-ray absorption near edge spectroscopy (XANES)) and ultraviolet-visible spectroscopy. The EXAFS data show that SiOO{sub 2}-supported tantalum clusters were characterized by a Ta-Ta coordination number of approximately 2, consistent with the presence of tritantalum clusters, on average. When these were reduced in H{sub 2} and reoxidized in O{sub 2}, the cluster nuclearity remained essentially unchanged, although reduction and oxidation occurred, respectively, as shown by XANES and UV-vis spectra; in the reoxidation, the tantalum oxidation state change was approximately two electronic charges per tritantalum cluster. The data demonstrate an analogy between the chemistry of group 5 metals on the SiO{sub 2} support and their chemistry in solution, as determined by the group of Cotton.

Plating versus wiring for fixation of traumatic rib and sternal fractures

Directory of Open Access Journals (Sweden)

Mostafa Kamel Abd-Elnaim

2017-12-01

Conclusions: Plating of rib and sternal fractures had better outcome than wiring, regarding better chest wall stability and restoration of chest contour; also it had shorter intensive care unit, hospital and ventilator days.

Upgrading tantalum and niobium oxides content in Bangka tin slag with double leaching

Science.gov (United States)

Soedarsono, J. W.; Permana, S.; Hutauruk, J. K.; Adhyputra, R.; Rustandi, A.; Maksum, A.; Widana, K. S.; Trinopiawan, K.; Anggraini, M.

2018-03-01

Tantalum has become one of the 14 types of critical materials where the level of its availability is assumed as the midterm critical metal. Benefits of the element tantalum in the electronics field increased the deficit balance of supply / demand, as more variations of electronic products developed. The tantalum experts calculated the level of availability until 2020. Base on the previous studies, tin slag is a secondary source of tantalum and niobium. This study uses tin slag from Bangka, Indonesia, abbreviated, Bangka Tin Slag (BTS). BTS was roasted, water quenched and sieved, abbreviated BTS-RQS.BTS was roasted, water quenched and sieved, abbreviated BTS-RQS.BTS-RQS was roasted at a temperature 700□C given sample code BTS-R700QS, while roasted at 800°C given sample code BTS-R800QS.A variable leaching experiment on BTS-R700QS was solvent concentration variable and on BTS-R800QS was time variable. The entire residue was characterized by X-Ray Fluorescence (XRF), and the optimum results are on the BTS-R800QS leaching into 5 M NaOH for 20 min followed by 5M HCl for 50 min, with content of Ta2O5 and Nb2O51.56% and 1.11%, respectively. The result of XRF measurement showed was the increasing of TNO content due to the increasing solvent concentration and time of acid leaching. The discussion of thermodynamics this study used was HSC Chemistry 6 as a supporting data.

Evaluation of Polymer Hermetically Sealed Tantalum Capacitors

Science.gov (United States)

Teverovsky, Alexander A.

2014-01-01

Polymer cathode tantalum capacitors have lower ESR (equivalent series resistance) compared to other types of tantalum capacitors and for this reason have gained popularity in the electronics design community. Their use allows improved performance of power supply systems along with substantial reduction of size and weight of the components used. However, these parts have poor thermal stability and can degrade in humid environments. Polymer hermetically sealed (PHS) capacitors avoid problems related to environmental degradation of molded case parts and can potentially replace current wet and solid hermetically sealed capacitors. In this work, PHS capacitors manufactured per DLA LAM DWG#13030 are evaluated for space applications. Several lots of capacitors manufactured over period from 2010 to 2014 were tested for the consistency of performance, electrical and thermal characteristics, highly accelerated life testing, and robustness under reverse bias and random vibration conditions. Special attention was given to analysis of leakage currents and the effect of long-term high temperature storage on capacitors in as is condition and after hermeticity loss. The results show that PHS capacitors might be especially effective for low-temperature applications or for system requiring a cold start-up. Additional screening and qualification testing have been recommended to assure the necessary quality of capacitors for space projects.

Does the titanium plate fixation of symphyseal fracture affect mandibular growth?

Science.gov (United States)

Bayram, Burak; Yilmaz, Alev Cetinsahin; Ersoz, Esra; Uckan, Sina

2012-11-01

The effect of metallic fixation on growth is a major concern in children and is not yet clear. The aim of this study was to evaluate the effect of metallic fixation of mandibular symphyseal fracture on mandibular growth.Eighteen 90-day-old growing white New Zealand rabbits weighing 1.6 to 2.5 kg were included in this study and divided into 2 groups of 9 subjects. In the experimental group, animals underwent mandibular osteotomy, simulating a symphyseal fracture on the midline of mandibular symphysis. The bone segments were fixed with microplates and microscrews (1.6 mm).In the control group, the same surgical incision without performing symphyseal osteotomy was conducted, and 2 screws were inserted on each side of the symphyseal midline.Digital cephalometric and submentovertex radiographs were taken before the operation and at postoperative 6 months for each animal in 2 groups, and cephalometric measurements were performed. The distance between the centers of the head of 2 screws measured at the end of surgery in the control group was compared with measurements at 6 months after surgery. Obtained data were statistically analyzed.There is no statistically significant difference between the 2 groups for growth amount of both sides of the mandible. Difference of ANS-Id (the most anterior points of nasal bone, the most anterior point on the alveolar bone between the lower incisors) and Cd-Id (the uppermost and most distal point of the mandibular condyle, the most anterior point on the alveolar bone between the lower incisors) values of the 2 groups is not statistically significant (P > 0.05).The distance between the 2 screws at the first application significantly increased at the postoperative sixth month (P mandibular symphyseal fracture does not affect the vertical and sagittal mandibular growth in growing rabbits.

Comparison of circummandibular wiring with resorbable bone plates in pediatric mandibular fractures.

Science.gov (United States)

Saikrishna, D; Gupta, Nimish

2010-06-01

Pediatric patients present a unique challenge to maxillofacial surgeons in terms of their treatment planning as well as in their functional and nutritional needs which are different from that of adult patients. Early literature has advocated conservative closed management of pediatric fractures to prevent complications. However recent advances in maxillofacial surgery has enabled us to use biodegradable plates and screws, which overcomes the limitations of metallic plates. We present a comparison of two cases of parasymphysis fracture treated with circum-mandibular wiring and biodegradable plate fixation their outcome in terms of fracture healing and functional stability.

Reverse Less Invasive Stabilization System (LISS) Plating for Proximal Femur Fractures in Poliomyelitis Survivors: A Report of Two Cases.

Science.gov (United States)

Yao, Chen; Jin, Dongxu; Zhang, Changqing

2017-11-15

BACKGROUND Poliomyelitis is a neuromuscular disease which causes muscle atrophy, skeletal deformities, and disabilities. Treatment of hip fractures on polio-affect limbs is unique and difficult, since routine fixation methods like nailing may not be suitable due to abnormal skeletal structures. CASE REPORT We report one femoral neck fracture and one subtrochanteric fracture in polio survivors successfully treated with reverse less invasive stabilization system (LISS) plating technique. Both fractures were on polio-affected limbs with significant skeletal deformities and low bone density. A contralateral femoral LISS plate was applied upside down to the proximal femur as an internal fixator after indirect or direct reduction. Both patients had uneventful bone union and good functional recovery. CONCLUSIONS Reverse LISS plating is a safe and effective technique to treat hip fractures with skeletal deformities caused by poliomyelitis.

Establishment of an analytical procedure for the determination of niobium and tantalum in minerals containing these elements using X-ray fluorescence technique

International Nuclear Information System (INIS)

Nguyen Xuan Chien

2003-01-01

The study of determination of niobium, tantalum in mineral and tin slags using X-ray fluorescence spectrometry was carried out. Analytical samples of powder and pellet were prepared. the interference of the major accompanied elements in sample with the determination of niobium and tantalum was also studied. The analysis of niobium and tantalum in mineral and in tin slags samples was given in this work. (author)

MINIMUM INCISION PERCUTANEOUS PLATE OSTEOSYNTHESIS FOR DISTAL FIBULAR FRACTURES: A PROSPECTIVE STUDY

Directory of Open Access Journals (Sweden)

Ramkumar Reddy

2015-09-01

Full Text Available Distal fibular fractures are usually communitted and most of the times osteoporotic especially if they are occurring in females and in geriatric age group. These fractures are usu ally associated with other fractures, which necessitates them to be fixed accurately. Owing to the fact that distal fragment is subcutaneous with scanty soft tissue over bone, which pose these fracture fixations become difficult by open methods in view of wound healing. A prospective study of 26 patients with distal fibular fractures were treated with MIPPO with hook plate were healed with less complications and better outcome. With this background we suggest a minimally invasive incision over proximal frag ment where sufficient soft tissue cover is present. From there pushing the special hook plate subperiosteally to distal fragment, hooking the tip of fibula and fixing the proximal fragment after reduction gives a simple and effective stable fixation

Finite element analysis of three patterns of internal fixation of fractures of the mandibular condyle.

Science.gov (United States)

Aquilina, Peter; Chamoli, Uphar; Parr, William C H; Clausen, Philip D; Wroe, Stephen

2013-06-01

The most stable pattern of internal fixation for fractures of the mandibular condyle is a matter for ongoing discussion. In this study we investigated the stability of three commonly used patterns of plate fixation, and constructed finite element models of a simulated mandibular condylar fracture. The completed models were heterogeneous in the distribution of bony material properties, contained about 1.2 million elements, and incorporated simulated jaw-adducting musculature. Models were run assuming linear elasticity and isotropic material properties for bone. This model was considerably larger and more complex than previous finite element models that have been used to analyse the biomechanical behaviour of differing plating techniques. The use of two parallel 2.0 titanium miniplates gave a more stable configuration with lower mean element stresses and displacements over the use of a single miniplate. In addition, a parallel orientation of two miniplates resulted in lower stresses and displacements than did the use of two miniplates in an offset pattern. The use of two parallel titanium plates resulted in a superior biomechanical result as defined by mean element stresses and relative movement between the fractured fragments in these finite element models. Copyright © 2012 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Surgical treatment of proximal humerus fractures using PHILOS plate

Directory of Open Access Journals (Sweden)

Vijay Sharma

2014-10-01

Full Text Available 【Abstract】Objective: To evaluate functional outcome and complications of open reduction and internal fixation with proximal humeral internal locking system (PHILOS plate for proximal humerus fractures. Methods: We reviewed 51 patients who underwent open reduction and internal fixation with PHILOS plate between the years 2007 to 2012. There were 35 men and 16 women with a mean age of 38 years (range 24-68. There were 41 patients in the age group of <60 years and 10 patients in the age group of >60 years. According to Neer classification system, 8, 15 and 23 patients had 2-part, 3-part, and 4-part fractures, respectively and 5 patients had 4-part fracture dislocation. All surgeries were carried out at our tertiary care trauma centre. Functional evaluation of the shoulder at final follow-up was done using Constant-Murley score. Results: The mean follow-up period was 30 months (range 12-44 months. Two patients were lost to followup. Of the remaining 49 patients, all fractures were united clinically and radiologically. The mean time for radiological union was 12 weeks (range 8-20 weeks. At the final follow-up the mean Constant-Murley score was 79 (range 50-100. The results were excellent in 25 patients, good in 13 patients, fair in 6 atients and poor in 5 patients. During the follow-up, four cases of varus malunion, one case of subacromial impingement, one case of deep infection, one case of intraarticular screw penetration and one case of failure of fi xation were noted. No cases of avascular necrosis, hardware failure, locking screw loosening or nonunion were noted. Conclusion: PHILOS provides stable fixation in proximal humerus fractures. To prevent potential complications like avascular necrosis, meticulous surgical dissection to preserve vascularity of humeral head is necessary. Key words: Proximal humerus fracture; Fracture fixation, internal; Proximal humeral internal locking system

Origins of Beta Tantalum in Sputtered Coatings

National Research Council Canada - National Science Library

Mulligan, C

2001-01-01

.... Some of the most recent work has attempted to relate the energetics (i.e., atom/ion energy) of the plasma to the alpha right arrow beta transition. It has been shown that the energetics of the plasma can relate to the most crucial sputtering parameters. The most significant feature of the use of plasma energy to explain the alpha right arrow beta transition is that it relates the formation of beta-tantalum to a quantifiable measure.

An in vivo evaluation of PLLA/PLLA-gHA nano-composite for internal fixation of mandibular bone fractures.

Science.gov (United States)

Peng, Weihai; Zheng, Wei; Shi, Kai; Wang, Wangshu; Shao, Ying; Zhang, Duo

2015-11-09

Internal fixation of bone fractures using biodegradable poly(L-lactic-acid) (PLLA)-based materials has attracted the attention of many researchers. In the present study, 36 male beagle dogs were randomly assigned to two groups: PLLA/PLLA-gHA (PLLA-grafted hydroxyapatite) group and PLLA group. PLLA/PLLA-gHA and PLLA plates were embedded in the muscular bags of the erector spinae and also implanted to fix mandibular bone fractures in respective groups. At 1, 2, 3, 6, 9, and 12 months postoperatively, the PLLA/PLLA-gHA and PLLA plates were evaluated by adsorption and degradation tests, and the mandibles were examined through radiographic analysis, biomechanical testing, and histological analysis. The PLLA/PLLA-gHA plates were non-transparent and showed a creamy white color, and the PLLA plates were transparent and faint yellow in color. At all time points following surgery, adsorption and degradation of the PLLA/PLLA-gHA plates were significantly less than those of the PLLA plates, and the lateral and longitudinal bending strengths of the surgically treated mandibles of the beagle dogs in the PLLA/PLLA-gHA group were significantly greater than those of the PLLA group and reached almost the value of intact mandibles at 12 months postoperatively. Additionally, relatively rapid bone healing was observed in the PLLA/PLLA-gHA group with the formation of new lamellar bone tissues at 12 months after the surgery. The PLLA/PLLA-gHA nano-composite can be employed as a biodegradable material for internal fixation of mandibular bone fractures.

An in vivo evaluation of PLLA/PLLA-gHA nano-composite for internal fixation of mandibular bone fractures

International Nuclear Information System (INIS)

Peng, Weihai; Shi, Kai; Wang, Wangshu; Shao, Ying; Zhang, Duo; Zheng, Wei

2015-01-01

Internal fixation of bone fractures using biodegradable poly(L-lactic-acid) (PLLA)-based materials has attracted the attention of many researchers. In the present study, 36 male beagle dogs were randomly assigned to two groups: PLLA/PLLA-gHA (PLLA-grafted hydroxyapatite) group and PLLA group. PLLA/PLLA-gHA and PLLA plates were embedded in the muscular bags of the erector spinae and also implanted to fix mandibular bone fractures in respective groups. At 1, 2, 3, 6, 9, and 12 months postoperatively, the PLLA/PLLA-gHA and PLLA plates were evaluated by adsorption and degradation tests, and the mandibles were examined through radiographic analysis, biomechanical testing, and histological analysis. The PLLA/PLLA-gHA plates were non-transparent and showed a creamy white color, and the PLLA plates were transparent and faint yellow in color. At all time points following surgery, adsorption and degradation of the PLLA/PLLA-gHA plates were significantly less than those of the PLLA plates, and the lateral and longitudinal bending strengths of the surgically treated mandibles of the beagle dogs in the PLLA/PLLA-gHA group were significantly greater than those of the PLLA group and reached almost the value of intact mandibles at 12 months postoperatively. Additionally, relatively rapid bone healing was observed in the PLLA/PLLA-gHA group with the formation of new lamellar bone tissues at 12 months after the surgery. The PLLA/PLLA-gHA nano-composite can be employed as a biodegradable material for internal fixation of mandibular bone fractures. (paper)

Salvage of tibial pilon fractures using fusion of the ankle with a 90 degrees cannulated blade-plate: a preliminary report.

Science.gov (United States)

Morgan, S J; Thordarson, D B; Shepherd, L E

1999-06-01

Six patients with ankle joint destruction and delayed metaphyseal union after tibial plafond fracture were surgically treated with tibiotalar arthrodesis and metaphyseal reconstruction, using a fixed-angle cannulated blade-plate. The procedure was performed through a posterior approach in five cases and a lateral approach in one case. The subtalar joint was preserved in all cases. Metaphyseal union and a stable arthrodesis were obtained in all cases without loss of fixation and with no mechanical failure of the blade-plate. Union was obtained in an average of 26 weeks. No secondary procedures were required to obtain union. All six patients were ambulatory at last follow-up. Stable internal fixation for simultaneous tibiotalar fusion and metaphyseal reconstruction can be achieved with a cannulated blade-plate while preserving the subtalar joint in complex plafond fractures.

A Novel Murine Model of Established Staphylococcal Bone Infection in the Presence of a Fracture Fixation Plate to Study Therapies Utilizing Antibiotic-laden Spacers after Revision Surgery

Science.gov (United States)

Inzana, Jason A.; Schwarz, Edward M.; Kates, Stephen L.; Awad, Hani A.

2014-01-01

Mice are the small animal model of choice in biomedical research due to the low cost and availability of genetically engineered lines. However, the devices utilized in current mouse models of implant-associated bone infection have been limited to intramedullary or trans-cortical pins, which are not amenable to treatments involving extensive debridement of a full-thickness bone loss and placement of a segmental antibiotic spacer. To overcome these limitations, we developed a clinically faithful model that utilizes a locking fracture fixation plate to enable debridement of an infected segmental bone defect (full-thickness osteotomy) during a revision surgery, and investigated the therapeutic effects of placing an antibiotic-laden spacer in the segmental bone defect. To first determine the ideal time point for revision following infection, a 0.7 mm osteotomy in the femoral mid-shaft was stabilized with a radiolucent PEEK fixation plate. The defect was inoculated with bioluminescent Staphylococcus aureus, and the infection was monitored over 14 days by bioluminescent imaging (BLI). Osteolysis and reactive bone formation were assessed by X-ray and micro-computed tomography (micro-CT). The active bacterial infection peaked by 5 days post-inoculation, however the stability of the implant fixation became compromised by 10–14 days post-inoculation due to osteolysis around the screws. Thus, day 7 was defined as the ideal time point to perform the revision surgery. During the revision surgery, the infected tissue was debrided and the osteotomy was widened to 3 mm to place a poly-methyl methacrylate spacer, with or without vancomycin. Half of the groups also received systemic vancomycin for the remaining 21 days of the study. The viable bacteria remaining at the end of the study were measured using colony forming unit assays. Volumetric bone changes (osteolysis and reactive bone formation) were directly measured using micro-CT image analysis. Mice that were treated with

2014 NEPP Tasks Update for Ceramic and Tantalum Capacitors

Science.gov (United States)

Teverovsky, Alexander A.

2014-01-01

Presentation describes recent development in research on MnO2, wet, and polymer tantalum capacitors. Low-voltage failures in multilayer ceramic capacitors and techniques to reveal precious metal electrode (PME) and base metal electrode (BME) capacitors with cracks are discussed. A voltage breakdown technique is suggested to select high quality low-voltage BME ceramic capacitors.

Treatment of unstable sacral fractures with percutaneous reconstruction plate internal fixation Tratamento de fraturas sacrais instáveis com reconstrução percutânea com fixação de placa interna

Directory of Open Access Journals (Sweden)

Hong-Wei Chen

2012-05-01

Full Text Available PURPOSE: To study the effects of percutaneous reconstruction plate internal fixation in the treatment of unstable sacral fractures. METHODS: Percutaneous reconstruction plate internal fixation was applied on 21 cases of unstable sacral fracture (15 males and six females, at age range of 16-65 years, mean 38.3 years including four cases of Denis Zone I, 14 cases of Zone II and three cases of Zone III. In operation, an arc incision (about 3-5 cm long was made along the iliac crest on the outside border of posterior superior iliac spine (PSIS on both sides, and then the plate was transported from the wounded side to the opposite one through the subcutaneous tunnel. RESULTS: The mean incision length, operation time, intraoperative blood loss was 4.3cm, 45.2min, and 160.8ml respectively. All these patients were followed up for 12-33 months (average 16.3 months, which showed no incision infection, intraoperative neurovascular injury, internal fixation loose or breakage, disunion, or obvious lower limb length inequality. The function result was rated as excellent in six cases, good in 12 and fair in 3, with excellence rate of 85.7%, according to the Majeed scoring system. CONCLUSION: Percutaneous reconstruction plate internal fixation is an ideal surgical approach to unstable sacral fractures, as it is easy, safe, causing less trauma and fewer complications, and conducive to quicker recovery.OBJETIVO: Estudar os efeitos da reconstrução percutânea com fixação de placa interna no tratamento de fraturas sacrais instáveis. MÉTODOS: A reconstrução percutânea com fixação de placa interna foi aplicada em 21 casos de fratura sacral instável (15 homens e seis mulheres, com idade variando entre 16 e 65 anos, média de 38,3 anos incluindo quatro casos de Zona I de Denis, 14 casos de Zona II e três casos de Zona III. No ato operatório, uma incisão arqueada (cerca de 3 a 5cm de comprimento foi feita ao longo da crista ilíaca na borda externa da

Synergistic helium and deuterium blistering in tungsten–tantalum composites

International Nuclear Information System (INIS)

Dias, M.; Mateus, R.; Catarino, N.; Franco, N.; Nunes, D.; Correia, J.B.; Carvalho, P.A.; Hanada, K.; Sârbu, C.

2013-01-01

Abstruct: Tungsten–tantalum composites with 10 and 20 at.% Ta were prepared by ball milling W powder with Ta fibers and by consolidating the milled materials with spark plasma sintering. The composites were implanted at room temperature with He + (30 keV with a fluence 5 × 10 21 at/m 2 ) and/or D + (15 keV with a fluence 5 × 10 21 at/m 2 ) ion beams. The materials were studied by scanning and high-resolution transmission electron microscopy, both coupled with energy dispersive X-ray spectroscopy, and by X-ray diffraction, Rutherford backscattering spectrometry and nuclear reaction analysis. The microstructure observations revealed that the milling operation resulted in severe fragmentation of the Ta fibers. Furthermore, during the consolidation process the Ta phase acted as oxygen getter and reduced the W oxide present in the original material. The surface of the tungsten–tantalum composites implanted with D + remained essentially unaltered, while the materials implanted with He + evidenced blisters on the Ta-rich regions. D retention in the composites increased with He + pre-implantation

Intrascleral IOL Fixation.

Science.gov (United States)

Jacob, Soosan

2017-01-01

Intrascleral sutureless intraocular lens (IOL) fixation utilizes direct haptic fixation within the sclera in eyes with deficient capsular support. This has advantages of long-term stability, good control of tilt and decentration, and lesser pseudophakodonesis. This review summarizes various techniques for intrascleral haptic fixation, results, complications, adaptations in special situations, modifications of the technique, combination surgeries, and intrascleral capsular bag fixation techniques (glued capsular hook). Copyright 2017 Asia-Pacific Academy of Ophthalmology.

Use of the bioactive resorbable plate system for zygoma and zygomatic arch replacement and fixation with modified Crockett's method for maxillectomy: A technical note.

Science.gov (United States)

Sukegawa, Shintaro; Kanno, Takahiro; Shibata, Akane; Matsumoto, Kenichi; Sukegawa-Takahashi, Yuka; Sakaida, Kyousuke; Furuki, Yoshihiko

2017-07-01

As a surgical approach targeting the pterygopalatine fossa following maxillary cancer due to tumor invasion, Crockett's method is conventional and useful. However, if the tumor is confined to the area between the maxilla and pterygopalatine fossa, it is not necessary to include the zygomatico-orbital in the access osteotomy, and the orbital floor may be preserved. Depending on the range of tumor invasion, the current study reports a more minimally invasive, modified Crockett's surgery that may be considered, which includes resection with modified osteotomy lines and repositioning with fixation of the zygoma and zygomatic arch following maxillary cancer ablation. In addition, the majority of patients with advanced maxillary cancer may require postoperative radiotherapy or chemoradiotherapy following maxillectomy according to several guidelines. Therefore, using a low-profile bioactive resorbable plate system as a method of repositioning and fixing the resected and preserved zygoma and zygomatic arch may be more effective in this modified Crockett's method for maxillectomy.

Using external and internal locking plates in a two-stage protocol for treatment of segmental tibial fractures.

Science.gov (United States)

Ma, Ching-Hou; Tu, Yuan-Kun; Yeh, Jih-Hsi; Yang, Shih-Chieh; Wu, Chin-Hsien

2011-09-01

The tibial segmental fractures usually follow high-energy trauma and are often associated with many complications. We designed a two-stage protocol for these complex injuries. The aim of this study was to assess the outcome of tibial segmental fractures treated according to this protocol. A prospective series of 25 consecutive segmental tibial fractures were treated using a two-stage procedure. In the first stage, a low-profile locking plate was applied as an external fixator to temporarily immobilize the fractures after anatomic reduction had been achieved followed by soft-tissue reconstruction. The second stage involved definitive internal fixation with a locking plate using a minimally invasive percutaneous plate osteosynthesis technique. The median follow-up was 32 months (range, 20-44 months). All fractures achieved union. The median time for the proximal fracture union was 23 weeks (range, 12-30 weeks) and that for distal fracture union was 27 weeks (range, 12-46 weeks; p = 0.08). Functional results were excellent in 21 patients and good in 4 patients. There were three cases of delayed union of distal fracture. Valgus malunion >5 degrees occurred in two patients, and length discrepancy >1 cm was observed in two patients. Pin tract infection occurred in three patients. Use of the two-stage procedure for treatment of segmental tibial fractures is recommended. Surgeons can achieve good reduction with stable temporary fixation, soft-tissue reconstruction, ease of subsequent definitive fixation, and high union rates. Our patients obtained excellent knee and ankle joint motion, good functional outcomes, and a comfortable clinical course.

Fine target of deuterium

International Nuclear Information System (INIS)

Diaz Diaz, J.; Granados Gonzalez, C. E.; Gutierrez Bernal, R.

1959-01-01

A fine target of deuterium on a tantalum plate by the absorption method is obtained. In order to obtain the de gasification temperature an induction generator of high frequency is used and the deuterium pass is regulated by means of a palladium valve. Two vacuum measures are available, one to measure the high vacuum in the de gasification process of the tantalum plate and the other, for low vacuum, to measure the deuterium inlet in the installation and the deuterium pressure change in the installation after the absorption in the tantalum plate. A target of 48 μ gr/cm 2 thick is obtained. (Author) 1 refs

Fine target of deuterium; Blanco fino de deuterio

Energy Technology Data Exchange (ETDEWEB)

Diaz Diaz, J; Granados Gonzalez, C E; Gutierrez Bernal, R

1959-07-01

A fine target of deuterium on a tantalum plate by the absorption method is obtained. In order to obtain the de gasification temperature an induction generator of high frequency is used and the deuterium pass is regulated by means of a palladium valve. Two vacuum measures are available, one to measure the high vacuum in the de gasification process of the tantalum plate and the other, for low vacuum, to measure the deuterium inlet in the installation and the deuterium pressure change in the installation after the absorption in the tantalum plate. A target of 48 {mu} gr/cm{sup 2} thick is obtained. (Author) 1 refs.

Shock compression and quasielastic release in tantalum

International Nuclear Information System (INIS)

Johnson, J.N.; Hixson, R.S.; Tonks, D.L.; Gray, G.T. III

1994-01-01

Previous studies of quasielastic release in shock-loaded FCC metals have shown a strong influence of the defect state on the leading edge, or first observable arrival, of the release wave. This is due to the large density of pinned dislocation segments behind the shock front, their relatively large pinning separation, and a very short response time as determined by the drag coefficient in the shock-compressed state. This effect is entirely equivalent to problems associated with elastic moduli determination using ultrasonic methods. This is particularly true for FCC metals, which have an especially low Peierls stress, or inherent lattice resistance, that has little influence in pinning dislocation segments and inhibiting anelastic deformation. BCC metals, on the other hand, have a large Peierls stress that essentially holds dislocation segments in place at low net applied shear stresses and thus allows fully elastic deformation to occur in the complete absence of anelastic behavior. Shock-compression and release experiments have been performed on tantalum (BCC), with the observation that the leading release disturbance is indeed elastic. This conclusion is established by examination of experimental VISAR records taken at the tantalum/sapphire (window) interface in a symmetric-impact experiment which subjects the sample to a peak longitudinal stress of approximately 7.3 GPa, in comparison with characteristic code calculations. copyright 1994 American Institute of Physics

Periprosthetic Vancouver type B1 and C fractures treated by locking-plate osteosynthesis

DEFF Research Database (Denmark)

Froberg, Lonnie; Troelsen, Anders; Brix, Michael

2012-01-01

Historically, the treatment of periprosthetic femoral fractures (PFFs) has been associated with a high frequency of complications and reoperations. The preferred treatment is internal fixation, a revision of the femoral stem, or a combination of both. An improved understanding of plate use during...

Reduction and temporary stabilization of Tile C pelvic ring injuries using a posteriorly based external fixation system.

Science.gov (United States)

Martin, Murphy P; Rojas, David; Mauffrey, Cyril

2017-12-05

Tile C pelvic ring injuries are challenging to manage even in the most experienced hands. The majority of such injuries can be managed using percutaneous reduction techniques, and the posterior ring can be stabilized using percutaneous transiliac-transsacral screw fixation. However, a subgroup of patients present with inadequate bony corridors, significant sacral zone 2 comminution or significant lateral/vertical displacement of the hemipelvis through a complete sacral fracture. Percutaneous strategies in such circumstances can be dangerous. Those patients may benefit from prone positioning and open reduction of the sacral fracture with fixation through tension band plating or lumbo-pelvic fixation. Soft tissue handling is critical, and direct reduction techniques around the sacrum can be difficult due to the complex anatomy and the fragile nature of the sacrum making clamp placement and tightening a challenge. In this paper, we propose a mini-invasive technique of indirect reduction and temporary stabilization, which is soft tissue friendly and permits maintenance of reduction during definitive fixation surgical.

Determination of tantalum in standard steels by INAA and absorption spectrophotometry

Energy Technology Data Exchange (ETDEWEB)

Obrusnik, I; Posta, S [Ustav Jaderneho Vyzkumu, Rez (Czechoslovakia)

1978-02-14

Two analytical methods, instrumental neutron activation analysis (INAA) and absorption spectrophotometry with malachite green, have been used for the determination of tantalum in standard steels produced by the Research Institute of CKD Prague - steels No. 167 and No. 169 with expected concentrations of Ta 0.01% and 0.03%, respectively. INAA method consisted of irradiation of steel samples (chips) in a nuclear reactor and Ge(Li) ..gamma..-ray spectrometry after a cooling period of one month. A spectrophotometric determination is based on the extraction of ionic associate of TaF/sub 6//sup -/ with malachite green into Oenzene from a solution of diluted sulphuric acid and hydrofluoric acid. The results obtained by the two methods are in a good agreement. However, INAA method is more sensitive and precise then spectrophotometry for the determination of tantalum in steels in the above-mentioned concentration ranges.

Determination of tantalum in standard steels by INAA and absorption spectrophotometry

International Nuclear Information System (INIS)

Obrusnik, I.; Posta, S.

1978-01-01

Two analytical methods, instrumental neutron activation analysis (INAA) and absorption spectrophotometry with malachite green, have been used for the determination of tantalum in standard steels produced by the Research Institute of CKD Prague - steels No. 167 and No. 169 with expected concentrations of Ta 0.01% and 0.03%, respectively. INAA method consisted of irradiation of steel samples (chips) in a nuclear reactor and Ge(Li) γ-ray spectrometry after a cooling period of one month. A spectrophotometric determination is based on the extraction of ionic associate of TaF 6 - with malachite green into Oenzene from a solution of diluted sulphuric acid and hydrofluoric acid. The results obtained by the two methods are in a good agreement. However, INAA method is more sensitive and precise then spectrophotometry for the determination of tantalum in steels in the above-mentioned concentration ranges. (author)

An in vitro biomechanical comparison of hydroxyapatite coated and uncoated ao cortical bone screws for a limited contact: dynamic compression plate fixation of osteotomized equine 3rd metacarpal bones.

Science.gov (United States)

Durham, Myra E; Sod, Gary A; Riggs, Laura M; Mitchell, Colin F

2015-02-01

To compare the monotonic biomechanical properties of a broad 4.5 mm limited contact-dynamic compression plate (LC-DCP) fixation secured with hydroxyapatite (HA) coated cortical bone screws (HA-LC-DCP) versus uncoated cortical bone screws (AO-LC-DCP) to repair osteotomized equine 3rd metacarpal (MC3) bones. Experimental. Adult equine cadaveric MC3 bones (n = 12 pair). Twelve pairs of equine MC3 were divided into 3 test groups (4 pairs each) for: (1) 4 point bending single cycle to failure testing; (2) 4 point bending cyclic fatigue testing; and (3) torsional single cycle to failure testing. For the HA-LC-DCP-MC3 construct, an 8-hole broad LC-DCP (Synthes Ltd, Paoli, PA) was secured on the dorsal surface of each randomly selected MC3 bone with a combination of four 5.5 mm and four 4.5 mm HA-coated cortical screws. For the AO-LC-DCP-MC3 construct, an 8-hole 4.5 mm broad LC-DCP was secured on the dorsal surface of the contralateral MC3 bone with a combination of four 5.5 mm and four 4.5 mm uncoated cortical screws. All MC3 bones had mid-diaphyseal osteotomies. Mean test variable values for each method were compared using a paired t-test within each group. Significance was set at P < .05. Mean yield load, yield bending moment, composite rigidity, failure load, and failure bending moment, under 4 point bending, single cycle to failure, of the HA-LC-DCP fixation were significantly greater than those of the AO-LC-DCP fixation. Mean ± SD values for the HA-LC-DCP and the AO-LC-DCP fixation techniques, respectively, in single cycle to failure under 4 point bending were: yield load, 26.7 ± 2.15 and 16.3 ± 1.38 kN; yield bending moment, 527.4 ± 42.4 and 322.9 ± 27.2 N-m; composite rigidity, 5306 ± 399 and 3003 ± 300 N-m/rad; failure load, 40.6 ± 3.94 and 26.5 ± 2.52 kN; and failure bending moment, 801.9 ± 77.9 and 522.9 ± 52.2 N-m. Mean cycles to failure in 4 point bending of the HA

Diffusion-Cooled Tantalum Hot-Electron Bolometer Mixers

Science.gov (United States)

Skalare, Anders; McGrath, William; Bumble, Bruce; LeDuc, Henry

2004-01-01

A batch of experimental diffusion-cooled hot-electron bolometers (HEBs), suitable for use as mixers having input frequencies in the terahertz range and output frequencies up to about a gigahertz, exploit the superconducting/normal-conducting transition in a thin strip of tantalum. The design and operation of these HEB mixers are based on mostly the same principles as those of a prior HEB mixer that exploited the superconducting/normal- conducting transition in a thin strip of niobium and that was described elsewhere.

Less-invasive stabilization of rib fractures by intramedullary fixation: a biomechanical evaluation.

Science.gov (United States)

Bottlang, Michael; Helzel, Inga; Long, William; Fitzpatrick, Daniel; Madey, Steven

2010-05-01

This study evaluated intramedullary fixation of rib fractures with Kirschner wires and novel ribs splints. We hypothesized that rib splints can provide equivalent fixation strength while avoiding complications associated with Kirschner wires, namely wire migration and cutout. The durability, strength, and failure modes of rib fracture fixation with Kirschner wires and rib splints were evaluated in 22 paired human ribs. First, intact ribs were loaded to failure to determine their strength. After fracture fixation with Kirschner wires and rib splints, fixation constructs were dynamically loaded to 360,000 cycles at five times the respiratory load to determine their durability. Finally, constructs were loaded to failure to determine residual strength and failure modes. All constructs sustained dynamic loading without failure. Dynamic loading caused three times more subsidence in Kirschner wire constructs (1.2 mm +/- 1.4 mm) than in rib splint constructs (0.4 mm +/- 0.2 mm, p = 0.09). After dynamic loading, rib splint constructs remained 48% stronger than Kirschner wire constructs (p = 0.001). Five of 11 Kirschner wire constructs failed catastrophically by cutting through the medial cortex, leading to complete loss of stability and wire migration through the lateral cortex. The remaining six constructs failed by wire bending. Rib splint constructs failed by development of fracture lines along the superior and interior cortices. No splint construct failed catastrophically, and all splint constructs retained functional reduction and fixation. Because of their superior strength and absence of catastrophic failure mode, rib splints can serve as an attractive alternative to Kirschner wires for intramedullary stabilization of rib fractures, especially in the case of posterior rib fractures where access for plating is limited.

Tantalum acetabular augments in one-stage exchange of infected total hip arthroplasty: a case-control study.

Science.gov (United States)

Klatte, Till Orla; Kendoff, Daniel; Sabihi, Reza; Kamath, Atul F; Rueger, Johannes M; Gehrke, Thorsten

2014-07-01

During the one-stage exchange procedure for periprosthetic joint infection (PJI) after total hip arthroplasty (THA), acetabular defects challenge reconstructive options. Porous tantalum augments are an established tool for addressing acetabular destruction in aseptic cases, but their utility in septic exchange is unknown. This retrospective case-control study presents the initial results of tantalum augmentation during one-stage exchange for PJI. Primary endpoints were rates of re-infection and short-term complications associated with this technique. Study patients had no higher risk of re-infection with equivalent durability at early follow-up with a re-infection rate in both groups of 4%. In conclusion, tantalum augments are a viable option for addressing acetabular defects in one-stage exchange for septic THA. Further study is necessary to assess long-term durability when compared to traditional techniques for acetabular reconstruction. Copyright © 2014 Elsevier Inc. All rights reserved.

Biomechanical investigation of an alternative concept to angular stable plating using conventional fixation hardware.

Science.gov (United States)

Windolf, Markus; Klos, Kajetan; Wähnert, Dirk; van der Pol, Bas; Radtke, Roman; Schwieger, Karsten; Jakob, Roland P

2010-05-21

Angle-stable locking plates have improved the surgical management of fractures. However, locking implants are costly and removal can be difficult. The aim of this in vitro study was to evaluate the biomechanical performance of a newly proposed crossed-screw concept ("Fence") utilizing conventional (non-locked) implants in comparison to conventional LC-DCP (limited contact dynamic compression plate) and LCP (locking compression plate) stabilization, in a human cadaveric diaphyseal gap model. In eight pairs of human cadaveric femora, one femur per pair was randomly assigned to receive a Fence construct with either elevated or non-elevated plate, while the contralateral femur received either an LCP or LC-DCP instrumentation. Fracture gap motion and fatigue performance under cyclic loading was evaluated successively in axial compression and in torsion. Results were statistically compared in a pairwise setting. The elevated Fence constructs allowed significantly higher gap motion compared to the LCP instrumentations (axial compression: p concept can be of interest in cases were angle-stable implants are unavailable and can lead to new strategies in implant design.

[Comparison of external fixation with or without limited internal fixation for open knee fractures].

Science.gov (United States)

Li, K N; Lan, H; He, Z Y; Wang, X J; Yuan, J; Zhao, P; Mu, J S

2018-03-01

Objective: To explore the characteristics and methods of different fixation methods and prevention of open knee joint fracture. Methods: The data of 86 cases of open knee joint fracture admitted from January 2002 to December 2015 in Department of Orthopaedics, Affiliated Hospital of Chengdu University were analyzed retrospectively.There were 65 males and 21 females aged of 38.6 years. There were 38 cases treated with trans articular external fixation alone, 48 cases were in the trans articular external fixation plus auxiliary limited internal fixation group. All the patients were treated according to the same three stages except for different fixation methods. Observation of external fixation and fracture fixation, fracture healing, wound healing and treatment, treatment and related factors of infection control and knee function recovery. χ(2) test was used to analyze data. Results: Eleven patients had primary wound healing, accounting for 12.8%. Seventy-five patients had two wounds healed, accounting for 87.2%. Only 38 cases of trans articular external fixator group had 31 cases of articular surface reduction, accounting for 81.6%; Five cases of trans articular external fixator assisted limited internal fixation group had 5 cases of poor reduction, accounting for 10.4%; There was significant difference between the two groups (χ(2)=44.132, P external fixation group, a total of 23 cases of patients with infection, accounted for 60.5% of external fixation group; trans articular external fixation assisted limited internal fixation group there were 30 cases of patients with infection, accounting for the assistance of external fixator and limited internal fixation group 62.5%; There was significant difference between the two groups(χ(2)=0.035, P >0.05). Five cases of fracture nonunion cases of serious infection, patients voluntarily underwent amputation. The Lysholm Knee Scale: In the external fixation group, 23 cases were less than 50 points, accounting for 60

Biodegradable fixation of mandibular fractures in children: stability and early results.

Science.gov (United States)

Yerit, Kaan C; Hainich, Sibylle; Enislidis, Georg; Turhani, Dritan; Klug, Clemens; Wittwer, Gert; Ockher, Michael; Undt, Gerhard; Kermer, Christian; Watzinger, Franz; Ewers, Rolf

2005-07-01

The aim of this study was to assess the safety and efficiency of biodegradable self-reinforced (SR-PLDLA) bone plates and screws in open reduction and internal fixation of mandible fractures in children. Thirteen patients (5 female, 8 male; mean age 12 years, range 5-16 years) were operated on various fractures of the mandible (2 symphyseal, 6 parasymphyseal, 4 body, 3 angle, 1 ramus, 2 condylar fractures). The mean follow-up time was 26.4 months (range 10.9-43.4 months). Intermaxillary fixation was applied in cases with concomitant condylar fractures up to 3 weeks. Primary healing of the fractured mandible was observed in all patients. Postoperative complications were minor and transient. The outcome of the operations was not endangered. Adverse tissue reactions to the implants, malocclusion, and growth restrictions did not occur during the observation period. Pediatric patients benefit from the advantages of resorbable materials, especially from faster mobilization and the avoidance of secondary removal operations. Based on these preliminary results, self-reinforced fixation devices are safe and efficient in the treatment of pediatric mandible fractures. However, further clinical investigations are necessary to evaluate the long-term reliability.

Rapid synthesis of tantalum oxide dielectric films by microwave microwave-assisted atmospheric chemical vapor deposition

International Nuclear Information System (INIS)

Ndiege, Nicholas; Subramanian, Vaidyanathan; Shannon, Mark A.; Masel, Richard I.

2008-01-01

Microwave-assisted chemical vapor deposition has been used to generate high quality, high-k dielectric films on silicon at high deposition rates with film thicknesses varying from 50 nm to 110 μm using inexpensive equipment. Characterization of the post deposition products was performed by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Auger electron spectroscopy and Raman spectroscopy. Film growth was determined to occur via rapid formation and accumulation of tantalum oxide clusters from tantalum (v) ethoxide (Ta(OC 2 H 5 ) 5 ) vapor on the deposition surface

Effect of oxygen deficiency on electronic properties and local structure of amorphous tantalum oxide thin films

Energy Technology Data Exchange (ETDEWEB)

Denny, Yus Rama [Department of Physics Education, University of Sultan Ageng Tirtayasa, Banten 42435 (Indonesia); Firmansyah, Teguh [Department of Electrical Engineering, University of Sultan Ageng Tirtayasa, Banten 42435 (Indonesia); Oh, Suhk Kun [Department of Physics, Chungbuk National University, Cheongju 28644 (Korea, Republic of); Kang, Hee Jae, E-mail: hjkang@cbu.ac.kr [Department of Physics, Chungbuk National University, Cheongju 28644 (Korea, Republic of); Yang, Dong-Seok [Department of Physics Education, Chungbuk National University, Cheongju 28644 (Korea, Republic of); Heo, Sung; Chung, JaeGwan; Lee, Jae Cheol [Analytical Engineering Center, Samsung Advanced Institute of Technology, Suwon 16678 (Korea, Republic of)

2016-10-15

Highlights: • The effect of oxygen flow rate on electronic properties and local structure of tantalum oxide thin films was studied. • The oxygen deficiency induced the nonstoichiometric state a-TaOx. • A small peak at 1.97 eV above the valence band side appeared on nonstoichiometric Ta{sub 2}O{sub 5} thin films. • The oxygen flow rate can change the local electronic structure of tantalum oxide thin films. - Abstract: The dependence of electronic properties and local structure of tantalum oxide thin film on oxygen deficiency have been investigated by means of X-ray photoelectron spectroscopy (XPS), Reflection Electron Energy Loss Spectroscopy (REELS), and X-ray absorption spectroscopy (XAS). The XPS results showed that the oxygen flow rate change results in the appearance of features in the Ta 4f at the binding energies of 23.2 eV, 24.4 eV, 25.8, and 27.3 eV whose peaks are attributed to Ta{sup 1+}, Ta{sup 2+}, Ta{sup 3+}/Ta{sup 4+}, and Ta{sup 5+}, respectively. The presence of nonstoichiometric state from tantalum oxide (TaOx) thin films could be generated by the oxygen vacancies. In addition, XAS spectra manifested both the increase of coordination number of the first Ta-O shell and a considerable reduction of the Ta-O bond distance with the decrease of oxygen deficiency.

REVISION ANKLE SYNDESMOSIS FIXATION - FUNCTIONAL OUTCOME AFTER TIGHTROPE ® FIXATION

Directory of Open Access Journals (Sweden)

Sendhilvelan Rajagopalan

2016-07-01

Full Text Available BACKGROUND Syndesmotic disruptions are often seen in ankle fractures. Malreduction of these fractures can result in arthritis and instability. A proportion of these patients with malreduction require revision fixation. This study presents the results of revision fixation in such patients, using the Ankle TightRope ® (Arthrex system. METHODS Between January 2000 to December 2009, 124 patients who underwent ankle fracture fixations with syndesmotic stabilisation were analysed. Out of 124 patients, 8 patients were diagnosed with failure of primary stabilisation (based on radiological and clinical criteria and subjected to revision fixation using the Ankle TightRope ® (Arthrex system. Followup was done at periodic time intervals of 3, 6 and 12 months. Both clinical and radiological assessment was performed. Complications and duration of hospital stay was recorded. Functional evaluation was performed using the American Orthopaedic Foot and Ankle Society (AOFAS scoring system. RESULTS Five patients had good results, one satisfactory and two had poor outcomes. CONCLUSIONS Ankle TightRope ® fixation is an alternative method of stabilisation in patients who require revision syndesmosis fixation. Further studies are required to evaluate this method of revision stabilisation as compared to screws.

[Contact characteristics research of acetabular weight-bearing area with different internal fixation methods after compression fracture of acetabular dome].

Science.gov (United States)

Xu, Bowen; Zhang, Qingsong; An, Siqi; Pei, Baorui; Wu, Xiaobo

2017-08-01

To establish the model of compression fracture of acetabular dome, and to measure the contact characteristics of acetabular weight-bearing area of acetabulum after 3 kinds of internal fixation. Sixteen fresh adult half pelvis specimens were randomly divided into 4 groups, 4 specimens each group. Group D was the complete acetabulum (control group), and the remaining 3 groups were prepared acetabular dome compression fracture model. The fractures were fixed with reconstruction plate in group A, antegrade raft screws in group B, and retrograde raft screws in group C. The pressure sensitive films were attached to the femoral head, and the axial compression test was carried out on the inverted single leg standing position. The weight-bearing area, average stress, and peak stress were measured in each group. Under the loading of 500 N, the acetabular weight-bearing area was significantly higher in group D than in other 3 groups ( P area were significantly higher in group B and group C than in group A, and the average stress and peak stress were significantly lower than in group A ( P 0.05). For the compression fracture of the acetabular dome, the contact characteristics of the weight-bearing area can not restore to the normal level, even if the anatomical reduction and rigid internal fixation were performed; compared with the reconstruction plate fixation, antegrade and retrograde raft screws fixations can increase the weight-bearing area, reduce the average stress and peak stress, and reduce the incidence of traumatic arthritis.

Hydroxyaromatic compounds of tantalum, tungsten, and the lighter actinides

International Nuclear Information System (INIS)

Gfaller, H.

1980-01-01

Some hydroxyaromatic compounds of the elements tantalum, tungsten, thorium and uranium were prepared as well as the basic materials for these synthesis processes, i.e. metal halides and metal alkoxides. The hydroxyaromatic compounds were studied by elemental analysis, IR spectroscopy, 1 H-NMR spectroscopy (if soluble in suitable solvents) and, in some cases, by X-ray fine structure analysis. (orig./EF) [de

Mass transfer modeling on the separation of tantalum and niobium from dilute hydrofluoric media through a hollow fiber supported liquid membrane

International Nuclear Information System (INIS)

Buachuang, Duenphen; Ramakul, Prakorn; Leepipatpiboon, Natchanun; Pancharoen, Ura

2011-01-01

Highlights: → Simultaneous separation of tantalum and niobium from the mixture solution. → An extraction through a hollow fiber supported liquid membrane (HFSLM). → The effect on tantalum removal found from Aliquat 336. → The mathematical model focusing on the extraction side of the liquid membrane system was presented. → The mass transfer coefficients of the aqueous feed (k i ) and the organic membrane phase (k m ) for the system were estimated as 1.19 x 10 -5 and 1.39 x 10 -7 cm/s, respectively. → Experimental data and theoretical values were found to be in good agreement when the concentration of Aliquat336 in the membrane phase was below 4% (v/v). - Abstract: The separation of a mixture of tantalum and niobium in dilute hydrofluoric media via hollow fiber supported liquid membrane (HFSLM) was examined. Quaternary ammonium salt (Aliquat336) diluted in kerosene was used as a carrier. The various effects on the transport and separation of tantalum and niobium were studied: concentration of hydrofluoric acid in the feed solution, concentration of the carrier (Aliquat336) in the membrane phase, types of stripping solutions (NaClO 4 , thiourea and HCl) and their concentration. The extraction of tantalum in the membrane phase from 0.3 M hydrofluoric acid (HF) by 3% (v/v) Aliquat336 was achieved by leaving niobium in the feed solution. Quantitative recovery of tantalum was achieved by 0.2 M NaClO 4 . Furthermore, a mathematical model focusing on the extraction side of the liquid membrane system was presented in order to predict the concentration of tantalum at different times. The mass transfer coefficients of the aqueous feed (k i ) and the organic membrane phase (k m ) were estimated as 1.19 x 10 -5 and 1.39 x 10 -7 cm/s, respectively. Therefore, the mass transfer limiting step is the diffusion of tantalum-Aliquat336 through the liquid membrane. Moreover, mass transfer modeling was performed and the validity of the developed model evaluated. Experimental

Mass transfer modeling on the separation of tantalum and niobium from dilute hydrofluoric media through a hollow fiber supported liquid membrane

Energy Technology Data Exchange (ETDEWEB)

Buachuang, Duenphen [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330 (Thailand); Ramakul, Prakorn [Department of Chemical Engineering, Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom 73000 (Thailand); Leepipatpiboon, Natchanun [Chromatography and Separation Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Pancharoen, Ura, E-mail: ura.p.@chula.ac.th [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330 (Thailand)

2011-09-29

Highlights: > Simultaneous separation of tantalum and niobium from the mixture solution. > An extraction through a hollow fiber supported liquid membrane (HFSLM). > The effect on tantalum removal found from Aliquat 336. > The mathematical model focusing on the extraction side of the liquid membrane system was presented. > The mass transfer coefficients of the aqueous feed (k{sub i}) and the organic membrane phase (k{sub m}) for the system were estimated as 1.19 x 10{sup -5} and 1.39 x 10{sup -7} cm/s, respectively. > Experimental data and theoretical values were found to be in good agreement when the concentration of Aliquat336 in the membrane phase was below 4% (v/v). - Abstract: The separation of a mixture of tantalum and niobium in dilute hydrofluoric media via hollow fiber supported liquid membrane (HFSLM) was examined. Quaternary ammonium salt (Aliquat336) diluted in kerosene was used as a carrier. The various effects on the transport and separation of tantalum and niobium were studied: concentration of hydrofluoric acid in the feed solution, concentration of the carrier (Aliquat336) in the membrane phase, types of stripping solutions (NaClO{sub 4}, thiourea and HCl) and their concentration. The extraction of tantalum in the membrane phase from 0.3 M hydrofluoric acid (HF) by 3% (v/v) Aliquat336 was achieved by leaving niobium in the feed solution. Quantitative recovery of tantalum was achieved by 0.2 M NaClO{sub 4}. Furthermore, a mathematical model focusing on the extraction side of the liquid membrane system was presented in order to predict the concentration of tantalum at different times. The mass transfer coefficients of the aqueous feed (k{sub i}) and the organic membrane phase (k{sub m}) were estimated as 1.19 x 10{sup -5} and 1.39 x 10{sup -7} cm/s, respectively. Therefore, the mass transfer limiting step is the diffusion of tantalum-Aliquat336 through the liquid membrane. Moreover, mass transfer modeling was performed and the validity of the

Outcome after open reduction and internal fixation of intraarticular fractures of the calcaneum without the use of bone grafts

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Pendse Aniruddha

2006-01-01

Full Text Available Background: Intraarticular fractures of calcaneum are commenest type of calcaneal fractures. Lots of controversies exist about the ideal management for them. The focus is now shifting on operative management by open reduction and internal fixation for these fractures with or without the use of bone grafts. Method: Thirty intraarticular fractures classified by Essex Lopresti radiological classification, were treated by open reduction and fixation. The patients were followed over a mean period of 30 months (25-40 months. Results: All the fractures united at a mean duration of 14 weeks. 86% patients had excellent functional outcome with one patient having fair and one having poor functional outcome. Conclusion: Open reduction and internal fixation with plate is a good method for treatment of intraarticular fractures of calcaneum to achieve anatomical restoration of articular surface under vision, stable fixation, early mobilization and an option for primary subtalar arthrodesis if deemed necessary.

Evaluation of the syndesmotic-only fixation for Weber-C ankle fractures with syndesmotic injury.