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Sample records for limited internal fixation

  1. Percutaneous limited internal fixation combined with external fixation to treat open pelvic fractures concomitant with perineal lacerations.

    PubMed

    Chen, Linwei; Zhang, Guoyou; Wu, Yaoshen; Guo, Xiaoshan; Yuan, Wen

    2011-12-01

    External fixation combined with colostomy is a traditional management of the pelvic fractures associated with perineal lacerations. However, malunion and dysfunction caused by malreduction and loss of reduction are common. One-stage definitive fixation without soft tissue harassment is requisite for the treatment. The purpose of this study was to assess the outcome of 1-stage definitive fixation by combining percutaneous limited internal fixation and external fixation in the treatment of pelvic fractures with perineal lacerations. Eighteen adults with high-energy unstable pelvic ring fractures associated with perineal lacerations were admitted between June 2003 and December 2010. Mean follow-up was 28 months. After wound closure and colostomy, 10 patients received external fixation and percutaneous screw fixation, and 8 patients underwent external fixation. Demographics, wound and fracture classification, and Injury Severity Score were comparable between the groups (P>.05). Initial reduction quality was comparable between the groups (P=.14), but the loss of reduction during follow-up was more significant in the external fixation group (P=.004). Combined fixation achieved better functional results than external fixation (P=.02). There were 2 cases of superficial wound infection in each group (P=1.0). By combining debridement, wound closure, colostomy, percutaneous limited internal fixation, and external fixation, we improved pelvic fracture recovery while reducing the risk of infection. One-stage definitive fixation is a better choice than external fixation in the treatment of open pelvic fracture concomitant with perineal wound. PMID:22146197

  2. Eighth international congress on nitrogen fixation

    SciTech Connect

    Not Available

    1990-01-01

    This volume contains the proceedings of the Eighth International Congress on Nitrogen Fixation held May 20--26, 1990 in Knoxville, Tennessee. The volume contains abstracts of individual presentations. Sessions were entitled Recent Advances in the Chemistry of Nitrogen Fixation, Plant-microbe Interactions, Limiting Factors of Nitrogen Fixation, Nitrogen Fixation and the Environment, Bacterial Systems, Nitrogen Fixation in Agriculture and Industry, Plant Function, and Nitrogen Fixation and Evolution.

  3. Eighth international congress on nitrogen fixation. Final program

    SciTech Connect

    Not Available

    1990-12-31

    This volume contains the proceedings of the Eighth International Congress on Nitrogen Fixation held May 20--26, 1990 in Knoxville, Tennessee. The volume contains abstracts of individual presentations. Sessions were entitled Recent Advances in the Chemistry of Nitrogen Fixation, Plant-microbe Interactions, Limiting Factors of Nitrogen Fixation, Nitrogen Fixation and the Environment, Bacterial Systems, Nitrogen Fixation in Agriculture and Industry, Plant Function, and Nitrogen Fixation and Evolution.

  4. Internal fixation: a historical review.

    PubMed

    Greenhagen, Robert M; Johnson, Adam R; Joseph, Alison

    2011-08-01

    Internal fixation has become a pillar of surgical specialties, yet the evolution of these devices has been relatively short. The first known description of medical management of a fracture was found in the Edwin Smith Papyrus of Ancient Egypt (circa 2600 bc). The first description of internal fixation in the medical literature was in the 18th century. The advancement of techniques and technology over the last 150 years has helped to preserve both life and function. The pace of advancement continues to accelerate as surgeons continue to seek new technology for osseous fixation. The authors present a thorough review of the history of internal fixation and the transformation into a multibillion dollar industry. PMID:21944395

  5. Bicondylar tibial fractures: Internal or external fixation?

    PubMed

    Kumar, Gunasekaran; Peterson, Nicholas; Narayan, Badri

    2011-03-01

    Bicondylar fractures of the tibia, representing the Schatzker V and VI fractures represent a challenging problem. Any treatment protocol should aim at restoring articular congruity and the metaphyseo-diaphsyeal dissociation (MDD)-both of these are equally important to long-term outcome. Both internal and external fixations have their proponents, and each method of treatment is associated with its unique features and complications. We review the initial and definitive management of these injuries, and the advantages and disadvantages of each method of definitive fixation. We suggest the use of a protocol for definitive management, using either internal or external fixation as deemed appropriate. This protocol is based on the fracture configuration, local soft tissue status and patient condition. In a nutshell, if the fracture pattern and soft tissue status are amenable plate fixation (single or double) is performed, otherwise limited open reduction and articular surface reconstruction with screws and circular frame is performed. PMID:21430865

  6. Distal Humerus Fractures: Open Reduction Internal Fixation.

    PubMed

    Mighell, Mark A; Stephens, Brent; Stone, Geoffrey P; Cottrell, Benjamin J

    2015-11-01

    Distal humerus fractures are challenging injuries for the upper extremity surgeon. However, recent techniques in open reduction internal fixation have been powerful tools in getting positive outcomes. To get such results, the surgeon must be aware of how to properly use these techniques in their respective practices. The method of fixation depends on the fracture, taking the degree of comminution and the restoration of the columns and articular surface into account. This article helps surgeons understand the concepts behind open reduction internal fixation of the distal humerus and makes them aware of pitfalls that may lead to negative results. PMID:26498548

  7. Design and Optimization of Resorbable Silk Internal Fixation Devices

    NASA Astrophysics Data System (ADS)

    Haas, Dylan S.

    Limitations of current material options for internal fracture fixation devices have resulted in a large gap between user needs and hardware function. Metal systems offer robust mechanical strength and ease of implantation but require secondary surgery for removal and/or result in long-term complications (infection, palpability, sensitivity, etc.). Current resorbable devices eliminate the need for second surgery and long-term complications but are still associated with negative host response as well as limited functionality and more difficult implantation. There is a definitive need for orthopedic hardware that is mechanically capable of immediate fracture stabilization and fracture fixation during healing, can safely biodegrade while allowing complete bone remodeling, can be resterilized for reuse, and is easily implantable (self-tapping). Previous work investigated the use of silk protein to produce resorbable orthopedic hardware for non- load bearing fracture fixation. In this study, silk orthopedic hardware was further investigated and optimized in order to better understand the ability of silk as a fracture fixation system and more closely meet the unfulfilled market needs. Solvent-based and aqueous-based silk processing formulations were cross-linked with methanol to induce beta sheet structure, dried, autoclaved and then machined to the desired device/geometry. Silk hardware was evaluated for dry, hydrated and fatigued (cyclic) mechanical properties, in vitro degradation, resterilization, functionalization with osteoinductive molecules and implantation technique for fracture fixation. Mechanical strength showed minor improvements from previous results, but remains comparable to current resorbable fixation systems with the advantages of self-tapping ability for ease of implantation, full degradation in 10 months, ability to be resterilized and reused, and ability to release molecules for osteoinudction. In vivo assessment confirmed biocompatibility, showed

  8. Open reduction and internal fixation compared to closed reduction and external fixation in distal radial fractures

    PubMed Central

    Kopylov, Philippe; Geijer, Mats; Tägil, Magnus

    2009-01-01

    Background and purpose In unstable distal radial fractures that are impossible to reduce or to maintain in reduced position, the treatment of choice is operation. The type of operation and the choice of implant, however, is a matter of discussion. Our aim was to investigate whether open reduction and internal fixation would produce a better result than traditional external fixation. Methods 50 patients with an unstable or comminute distal radius fracture were randomized to either closed reduction and bridging external fixation, or open reduction and internal fixation using the TriMed system. The primary outcome parameter was grip strength, but the patients were followed for 1 year with objective clinical assessment, subjective outcome using DASH, and radiographic examination. Results At 1 year postoperatively, grip strength was 90% (SD 16) of the uninjured side in the internal fixation group and 78% (17) in the external fixation group. Pronation/supination was 150° (15) in the internal fixation group and 136° (20) in the external fixation group at 1 year. There were no differences in DASH scores or in radiographic parameters. 5 patients in the external fixation group were reoperated due to malunion, as compared to 1 in the internal fixation group. 7 other cases were classified as radiographic malunion: 5 in the external fixation group and 2 in the internal fixation group. Interpretation Internal fixation gave better grip strength and a better range of motion at 1 year, and tended to have less malunions than external fixation. No difference could be found regarding subjective outcome. PMID:19857180

  9. Mechanical testing of a device for subcutaneous internal anterior pelvic ring fixation versus external pelvic ring fixation

    PubMed Central

    2014-01-01

    Background Although useful in the emergency treatment of pelvic ring injuries, external fixation is associated with pin tract infections, the patient’s limited mobility and a restricted surgical accessibility to the lower abdomen. In this study, the mechanical stability of a subcutaneous internal anterior fixation (SIAF) system is investigated. Methods A standard external fixation and a SIAF system were tested on pairs of Polyoxymethylene testing cylinders using a universal testing machine. Each specimen was subjected to a total of 2000 consecutive cyclic loadings at 1 Hz with sinusoidal lateral compression/distraction (+/−50 N) and torque (+/− 0.5 Nm) loading alternating every 200 cycles. Translational and rotational stiffness were determined at 100, 300, 500, 700 and 900 cycles. Results There was no significant difference in translational stiffness between the SIAF and the standard external fixation when compared at 500 (p = .089), 700 (p = .081), and 900 (p = .266) cycles. Rotational stiffness observed for the SIAF was about 50 percent higher than the standard external fixation at 300 (p = .005), 500 (p = .020), and 900 (p = .005) cycles. No loosening or failure of the rod-pin/rod-screw interfaces was seen. Conclusions In comparison with the standard external fixation system, the tested device for subcutaneous internal anterior fixation (SIAF) in vitro has similar translational and superior rotational stiffness. PMID:24684828

  10. Acquired localized hypertrichosis induced by internal fixation and plaster cast application.

    PubMed

    Ma, Hui-Jun; Yang, Yang; Ma, Hui-Yong; Jia, Chi-Yu; Li, Ting-Hui

    2013-08-01

    Hypertrichosis refers to increased vellus hair growth and is independent to androgen excess. The acquired localized hypertrichosis (ALH) is one of the typical hypertrichosis, which mainly results from chronic irritation, inflammation, friction, and occlusion by plaster of Paris. Here, we report a young boy who had ALH on his right hand following a closed fracture with internal fixation and plaster cast application. The case is unusual because the hairy area is limited to the operative region of internal fixation. We suggest that the local vascular changes and skin inflammation induced by internal fixation and plaster cast application may be associated with ALH. PMID:24003283

  11. Management of Postoperative Spondylodiscitis with and without Internal Fixation.

    PubMed

    Wang, Xiang; Tao, Hairong; Zhu, Yanhui; Lu, Xiongwei; Hu, Xiaopeng

    2015-01-01

    Postoperative spondylodiscitis is relatively uncommon. This complication is associated with increased cost, and long-term of inability to work, and even morbidity. Although the majority of postoperative spondylodiscitis cases can be well managed by conservative treatment, postoperative spondylodiscitis after internal fixation and those cases that are unresponsive to the conservative treatment present challenges to the surgeon. Here, a review was done to analyze the treatment of postoperative spondylodiscitis with/without internal fixation. This review article suggested that majority of postoperative spondylodiscitis without internal fixation could be cured by conservative treatment. Either posterior or anterior debridement can be used to treat postoperative spondylodiscitis without internal fixation when conservative treatment fails. In addition, minimally invasive debridement and drainage may also be an alternative treatment. In case of postoperative spondylodiscitis after internal fixation, surgical treatment was required. In the cervical spine, it can be well managed by anterior debridement, removal of internal fixation, and reconstruction of the spinal stability by using bone grafting/cage/anterior plate. Postoperative spondylodiscitis after internal fixation is successfully managed by combined anterior debridement, fusion with posterior approach and removal of pedicle screw or extension of pedicle screw beyond the lesion site, in the thoracic and lumbar spine. PMID:26242325

  12. Open Reduction Internal Fixation Poststernotomy Mediastinitis

    PubMed Central

    Dionisopoulos, Tassos

    2013-01-01

    Introduction. Mediastinitis has been reported to complicate 5% of sternotomy surgery. We have adopted an open reduction and rigid internal fixation (ORIF) approach during the conventional rescue surgery in the treatment of mediastinitis. Methods. A retrospective review was performed to compare the outcomes of patients that had an ORIF to correct postoperative mediastinitis following median sternotomy. These were compared with the outcome of the patients that did not undergo ORIF. Results. In the 5-year study period, we reviewed 35 mediastinitis patient charts. Postoperatively, the ORIF patient group remained in the Intensive Care Unit (ICU) and on a ventilator for a mean of 1.5 and 0.75 days, respectively. Patients treated without ORIF spent significantly more days in the ICU (mean of 7.5 days, P < 0.05) and on a ventilator (mean of 2.15 days, P = 0.1). Furthermore, it was found that none of the patients (0%) who underwent ORIF complained of any postoperative sternal instability or pain. Preoperatively, however, these rates were as high as 72%. Conclusions. In the select patient, ORIF can be a safe option in the management of mediastinitis, which we have shown to significantly decrease morbidity and mortality by providing anatomic reduction as well as physiologic stabilization. We have shown that ORIF will improve the quality of life of the patient by minimizing abnormal sternal mobility and pain and will also decrease inpatient costs by decreasing days spent in the ICU and ventilator dependence. PMID:23970966

  13. Diagnosis and rehabilitation of deep wound infection and internal fixation rejection in elbow: A case report.

    PubMed

    Lu, Huiping; Song, Lin; Lin, Ying

    2016-06-01

    This study aims at diagnosis and rehabilitation of a rare case of deep wound infection and internal fixation rejection in elbow. The patient sustained a distal fracture in the humerus 1 year ago, which was internal fixed. The wound always effused and the elbow had pain and swelling; joint motion was limited. Blood sedimentation rate and C reactive protein level increased, bacterial culture suggested deep wound infection, and ultrasound indicated inflammation. The main diagnoses were deep wound infection and internal fixation rejection. Therapeutics interventions were antibiotic agents, physical therapy, operative debridement, incision, drainage, and exercise and physical therapy. One year later, the internal fixation was taken out. His elbow was fully mobilized and the fracture healed. He got back to his former job. When encountered deep wound infection again and again after internal fixation, rejection should be considered. Except for anti-infection treatment, rehabilitation cannot be neglected, or the healing process may be delayed. PMID:27281079

  14. Diagnosis and rehabilitation of deep wound infection and internal fixation rejection in elbow

    PubMed Central

    Lu, Huiping; Song, Lin; Lin, Ying

    2016-01-01

    Abstract This study aims at diagnosis and rehabilitation of a rare case of deep wound infection and internal fixation rejection in elbow. The patient sustained a distal fracture in the humerus 1 year ago, which was internal fixed. The wound always effused and the elbow had pain and swelling; joint motion was limited. Blood sedimentation rate and C reactive protein level increased, bacterial culture suggested deep wound infection, and ultrasound indicated inflammation. The main diagnoses were deep wound infection and internal fixation rejection. Therapeutics interventions were antibiotic agents, physical therapy, operative debridement, incision, drainage, and exercise and physical therapy. One year later, the internal fixation was taken out. His elbow was fully mobilized and the fracture healed. He got back to his former job. When encountered deep wound infection again and again after internal fixation, rejection should be considered. Except for anti-infection treatment, rehabilitation cannot be neglected, or the healing process may be delayed. PMID:27281079

  15. Clinical Results of Internal Fixation of Subcapital Femoral Neck Fractures

    PubMed Central

    Moon, Kyoung Ho; Shin, Joong Sup; Shin, Eun Ho; Ahn, Chi Hoon; Choi, Geon Hong

    2016-01-01

    Background Subcapital femoral neck is known to cause many complications, such as avascular necrosis (AVN) of the femoral head or nonunion, compared with other femoral neck fractures. The purpose of this study was to analyze the incidence of AVN and fixation failures in patients treated with internal fixation using cannulated screws for the subcapital femoral neck fractures. Methods This study targeted a total of 84 cases of subcapital femoral neck fractures that underwent internal fixation using cannulated screws. The average follow-up time after surgery was 36.8 months (range, 24 to 148 months). Results Nine hips (10.7%) showing AVN of the femoral head and 6 hips (7.1%) showing fixation failures were observed. The factors affecting the incidence of AVN of the femoral head after sustaining fractures correlated well with fracture types in the Garden classification (p = 0.030). The factors affecting fixation failure were the degree of reduction (p = 0.001) measured by the Garden alignment index and firm fixation (p = 0.009) assessed using the technique of 3-point fixation through the inferomedial cortical bone of the femoral neck. Conclusions The complication rates for subcapital femoral neck fractures were lower than those previously reported; hence, internal fixation could be a primary treatment option for these fractures. PMID:27247738

  16. MRI analysis of the ISOBAR TTL internal fixation system for the dynamic fixation of intervertebral discs: a comparison with rigid internal fixation

    PubMed Central

    2014-01-01

    Objectives Using magnetic resonance imaging (MRI), we analyzed the efficacy of the posterior approach lumbar ISOBAR TTL internal fixation system for the dynamic fixation of intervertebral discs, with particular emphasis on its effects on degenerative intervertebral disc disease. Methods We retrospectively compared the MRIs of 54 patients who had previously undergone either rigid internal fixation of the lumbar spine or ISOBAR TTL dynamic fixation for the treatment of lumbar spondylolisthesis. All patients had received preoperative and 6-, 12-, and 24-month postoperative MRI scans of the lumbar spine with acquisition of both routine and diffusion-weighted images (DWI). The upper-segment discs of the fusion were subjected to Pfirrmann grading, and the lumbar intervertebral discs in the DWI sagittal plane were manually drawn; the apparent diffusion coefficient (ADC) value was measured. Results ADC values in the ISOBAR TTL dynamic fixation group measured at the 6-, 12-, and 24-month postoperative MRI studies were increased compared to the preoperative ADC values. The ADC values in the ISOBAR TTL dynamic fixation group at 24 months postoperatively were significantly different from the preoperative values (P < 0.05). At 24 months, the postoperative ADC values were significantly different between the rigid fixation group and the ISOBAR TTL dynamic fixation group (P < 0.05). Conclusion MRI imaging findings indicated that the posterior approach lumbar ISOBAR TTL internal fixation system can prevent or delay the degeneration of intervertebral discs. PMID:24898377

  17. Combined Type II Odontoid Fracture with Jefferson's Fracture Treated with Temporary Internal Fixation.

    PubMed

    Pawar, Abhijit Yuvaraj; O'Leary, Patrick F

    2015-12-01

    An 18-year-old male presented after a motor vehicle rollover accident. Computed tomography (CT) scan confirmed the diagnosis of Type II odontoid fracture. Considering the patient's young age and the limitations of C1-C2 fusion including significant loss of cervical rotation, temporary internal fixation with a lateral mass fixation of C1 and pedicle fixation of C2 without fusion was done. CT scan done at 6-month follow-up visit showed healed odontoid fracture and excellent C1-C2 alignment. At ninth postoperative month, internal fixation was removed. Patient had normal movements of cervical spine at 1-year follow-up. Temporary internal fixation can be an important tool in the armamentarium of the surgeon in treating type II odontoid fractures in young adults and children. This strategy avoids the complications halo fixation and immobilizes the unstable C1-C2 segment without fusion. Removal of the internal fixation after healing allows restoration of the rotational motion. PMID:26713132

  18. Effectiveness of external fixator combined with T-plate internal fixation for the treatment of comminuted distal radius fractures.

    PubMed

    Han, L R; Jin, C X; Yan, J; Han, S Z; He, X B; Yang, X F

    2015-01-01

    This study compared the efficacy between external fixator combined with palmar T-plate internal fixation and simple plate internal fixation for the treatment of comminuted distal radius fractures. A total of 61 patients classified as type C according to the AO/ASIF classification underwent surgery for comminuted distal radius fractures. There were 54 and 7 cases of closed and open fractures, respectively. Moreover, 19 patients received an external fixator combined with T-plate internal fixation, and 42 received simple plate internal fixation. All patients were treated successfully during 12-month postoperative follow-up. The follow-up results show that the palmar flexion and dorsiflexion of the wrist, radial height, and palmar angle were significantly better in those treated with the external fixator combined with T-plate compared to those treated with the simple plate only (P < 0.05); however, there were no significant differences in radial-ulnar deviation, wrist range of motion, or wrist function score between groups (P > 0.05). Hence, the effectiveness of external fixator combined with T-plate internal fixation for the treatment of comminuted distal radius fractures was satisfactory. Patients sufficiently recovered wrist, forearm, and hand function. In conclusion, compared to the simple T-plate, the external fixator combined with T-plate internal fixation can reduce the possibility of the postoperative re-shifting of broken bones and keep the distraction of fractures to maintain radial height and prevent radial shortening. PMID:25867441

  19. Anterior subcutaneous internal fixation for treatment of unstable pelvic fractures

    PubMed Central

    2014-01-01

    Background Fractures of the pelvic ring including disruption of the posterior elements in high-energy trauma have both high morbidity and mortality rates. For some injury pattern part of the initial resuscitation includes either external fixation or plate fixation to close the pelvic ring and decrease blood loss. In certain situations – especially when associated with abdominal trauma and the need to perform laparotomies – both techniques may put the patient at risk of either pintract or deep plate infections. We describe an operative approach to percutaneously close and stabilize the pelvic ring using spinal implants as an internal fixator and report the results in a small series of patients treated with this technique during the resuscitation phase. Findings Four patients were treated by subcutaneous placement of an internal fixator. Screw fixation was carried out by minimally invasive placement of two supra-acetabular iliac screws. Afterwards, a subcutaneous transfixation rod was inserted and attached to the screws after reduction of the pelvic ring. All patients were allowed to fully weight-bear. No losses of reduction or deep infections occurred. Fracture healing was uneventful in all cases. Conclusion Minimally invasive fixation is an alternative technique to stabilize the pelvic ring. The clinical results illustrate that this technique is able to achieve good results in terms of maintenance of reduction the pelvic ring. Also, abdominal surgeries no longer put the patient at risk of infected pins or plates. PMID:24606833

  20. Retrospective Comparison of Percutaneous Fixation and Volar Internal Fixation of Distal Radius Fractures

    PubMed Central

    Lozano-Calderón, Santiago A.; Doornberg, Job N.

    2007-01-01

    A change in the practice of a single surgeon provided an opportunity for retrospective comparison of comparable cohorts treated with percutaneous fixation (17 patients) or a volar plate and screws (23 patients) an average of 30 months after surgery. The final evaluation was performed according to the Gartland and Werley and Mayo rating systems and the DASH questionnaire. There were no significant differences on the average scores for the percutaneous and volar plating groups, respectively: Gartland and Werley, 4 vs 5; Mayo, 82 vs 83; and DASH score 13 for both cohorts. Motion, grip, and radiographical parameters were likewise comparable. Volar internal plate and screw fixation can achieve results comparable to percutaneous fixation techniques in the treatment of fractures of the distal radius. PMID:18780085

  1. Open reduction internal fixation of distal clavicle fracture with supplementary button coracoclavicular fixation.

    PubMed

    Hanflik, Andrew; Hanypsiak, Bryan T; Greenspoon, Joshua; Friedman, Darren J

    2014-10-01

    Distal clavicle fractures are common, and no standard treatment exists. Many different surgical modalities exist. This report describes an open reduction internal fixation technique that achieves both plate and coracoclavicular stabilization using a button device. A precontoured superior-lateral plate is secured to the clavicle. A 3.2-mm spade-tipped drill bit is drilled across the clavicle and coracoid, passing through 4 cortices. The button is loaded onto an insertion device, passed across the 4 cortices, and captured on the undersurface of the coracoid under fluoroscopic guidance. This construct is linked to the distal clavicle plate by heavy sutures using a second button that sits in the plate. The lateral locking holes are then filled to finalize fixation. This technique provides for a simplified way to achieve coracoclavicular stabilization when using a plate for fixation of distal clavicle fractures. PMID:25473604

  2. Open Reduction Internal Fixation of Distal Clavicle Fracture With Supplementary Button Coracoclavicular Fixation

    PubMed Central

    Hanflik, Andrew; Hanypsiak, Bryan T.; Greenspoon, Joshua; Friedman, Darren J.

    2014-01-01

    Distal clavicle fractures are common, and no standard treatment exists. Many different surgical modalities exist. This report describes an open reduction internal fixation technique that achieves both plate and coracoclavicular stabilization using a button device. A precontoured superior-lateral plate is secured to the clavicle. A 3.2-mm spade-tipped drill bit is drilled across the clavicle and coracoid, passing through 4 cortices. The button is loaded onto an insertion device, passed across the 4 cortices, and captured on the undersurface of the coracoid under fluoroscopic guidance. This construct is linked to the distal clavicle plate by heavy sutures using a second button that sits in the plate. The lateral locking holes are then filled to finalize fixation. This technique provides for a simplified way to achieve coracoclavicular stabilization when using a plate for fixation of distal clavicle fractures. PMID:25473604

  3. Physiological limitations and the genetic improvement of symbiotic nitrogen fixation

    SciTech Connect

    Gara, F.O.; Manian, S. ); Drevon, J.J. )

    1988-01-01

    The rhizobium legume symbiosis continues to be of strategic importance particularly in the context of food production. As the world population grows, it is necessary that new developments take place in crop improvement. The development and application of new technologies in biological sciences over past years has made the entire area of plant-microbial interaction an exciting and challenging research area to be involved in. In view of the importance of symbiotic nitrogen fixation, it is not surprising that it still represents one of the priority areas for commercial development in agricultural biotechnology. Since this symbiosis involves an association between procaryotic and eucaryhotic partners, it requires of necessity a coordinated and interdisciplinary approach. This book focuses on physiological limitations affecting symbiotic nitrogen fixation and the potential for overcoming such limitations by using genetic technologies.

  4. Open Reduction and Internal Fixation of Mandibular Fracture without Rigid Maxillomandibular Fixation.

    PubMed

    El-Anwar, Mohammad Waheed; Sayed El-Ahl, Magdy Abdalla; Amer, Hazem Saed

    2015-10-01

    Introduction The ability to treat fracture with open reduction and internal fixation (OR/IF) has dramatically revolutionized the approach to mandible fracture. With OR/IF, the postoperative role of rigid maxillomandibular fixation (MMF) has declined, but it is used to maintain proper occlusion until internal fixation of the fracture is achieved. Objective To assess intraoperative manual MMF during OR/IF of selected cases of mandibular fractures. Methods This prospective study was conducted on 80 patients with isolated mandibular fractures managed by OR/IF using two titanium miniplates. The patients were classified into two groups: a control group (40 patients) treated by OR/IF after intraoperative rigid MMF followed by immediate MMF removal, and a study group (40 patients) treated by rigid MMF, which was replaced by temporary intraoperative manual MMF (3MF) until plate fixation. Results There were no significant differences of the postoperative complication and dental occlusion, although a highly significant reduction of operative time was achieved in the 3MF group. Patient who received the 3MF technique had statistically significantly better average intrinsic vertical mouth opening in the early postoperative period (1 week after surgery), and normal mouth opening could be achieved in all cases in both groups 8 weeks after surgery. Conclusions Intraoperative rigid MMF is not mandatory and can be replaced in selected cases of fracture mandible by manual maintenance of proper dental occlusion until hardware fixation, gaining the advantages of shorter operative time and less risk of blood-transmitted diseases to the surgical team and the patient in addition to the benefits of immediate postoperative mandible mobilization. PMID:26491477

  5. Open Reduction and Internal Fixation of Mandibular Fracture without Rigid Maxillomandibular Fixation

    PubMed Central

    El-Anwar, Mohammad Waheed; Sayed El-Ahl, Magdy Abdalla; Amer, Hazem Saed

    2015-01-01

    Introduction The ability to treat fracture with open reduction and internal fixation (OR/IF) has dramatically revolutionized the approach to mandible fracture. With OR/IF, the postoperative role of rigid maxillomandibular fixation (MMF) has declined, but it is used to maintain proper occlusion until internal fixation of the fracture is achieved. Objective To assess intraoperative manual MMF during OR/IF of selected cases of mandibular fractures. Methods This prospective study was conducted on 80 patients with isolated mandibular fractures managed by OR/IF using two titanium miniplates. The patients were classified into two groups: a control group (40 patients) treated by OR/IF after intraoperative rigid MMF followed by immediate MMF removal, and a study group (40 patients) treated by rigid MMF, which was replaced by temporary intraoperative manual MMF (3MF) until plate fixation. Results There were no significant differences of the postoperative complication and dental occlusion, although a highly significant reduction of operative time was achieved in the 3MF group. Patient who received the 3MF technique had statistically significantly better average intrinsic vertical mouth opening in the early postoperative period (1 week after surgery), and normal mouth opening could be achieved in all cases in both groups 8 weeks after surgery. Conclusions Intraoperative rigid MMF is not mandatory and can be replaced in selected cases of fracture mandible by manual maintenance of proper dental occlusion until hardware fixation, gaining the advantages of shorter operative time and less risk of blood-transmitted diseases to the surgical team and the patient in addition to the benefits of immediate postoperative mandible mobilization. PMID:26491477

  6. Perspectives of patients about bioabsorbable internal fixation for maxillofacial fractures

    PubMed Central

    Landes, Constantin; Hoefer, Sebastian H.; Richards, Tereza; Walcher, Felix; Sader, Robert

    2015-01-01

    Purpose: Resorbable/bioabsorbable internal fixation provides effective treatment for maxillofacial fractures and avoids the need for metal hardware removal. We evaluated the initial knowledge, attitudes, subjective demand, and treatment satisfaction of patients concerning bioabsorbable osteofixation for maxillofacial trauma. Materials and Methods: From May 2007 to October 2009, there were 71 patients (63 males and 8 females; mean age: 35 ± 15 years) included in this prospective study. The patients completed preoperative and postoperative (4–6 weeks and 1 year) questionnaires. Results: After receiving information, 70 patients (99%) preferred resorbable/bioabsorbable bone fixation, usually because they preferred to avoid a second operation to remove metal hardware (67 patients [94%]). The higher cost of resorbable/bioabsorbable bone fixation was believed and justified by 41 patients (58%) and not justified by 30 patients (42%). No adverse events were reported by 27 of 34 patients (79%) at 4–6 weeks and by 14 of 21 patients (67%) at 1 year after surgery. Most patients were very satisfied with the outcome of surgery. Conclusion: Patients who have maxillofacial trauma have a high frequency of preference and high satisfaction with resorbable/bioabsorbable than metal osteofixation. Literature review showed increased activity in research and publication worldwide about resorbable bone fixation, suggesting that there may be increased patient demand for resorbable bone fixation in the future. PMID:26981468

  7. Fixation of Radiological Contamination; International Collaborative Development

    SciTech Connect

    Rick Demmer

    2013-03-01

    A cooperative international project was conducted by the Idaho National Laboratory (INL) and the United Kingdom’s National Nuclear Laboratory (NNL) to integrate a capture coating with a high performance atomizing process. The initial results were promising, and lead to further trials. The somewhat longer testing and optimization process has resulted in a product that could be demonstrated in the field to reduce airborne radiological dust and contamination.

  8. Primary internal fixation and soft-tissue reconstruction in the treatment for an open Lisfranc fracture-dislocation.

    PubMed

    Sanli, Ilknur; Hermus, Joris; Poeze, Martijn

    2012-06-01

    The importance of anatomical reduction for improved outcome has been recognised in the management of Lisfranc injuries. Operative fixation is indicated in case of dislocation or unstable ligamentous injury, because discongruity of the Lisfranc joint can lead to deleterious functional outcome. Screws are the recommended method of fixation of the medial en middle column, and K-wires are used for stabilisation of the unstable lateral column. Primary arthrodesis can provide advantages in pure ligamentous injury. In the management of complex open Lisfranc fractures, external fixation with K-wires can be used, but often results in a high percentage of arc deformities and functional limitations. In recent years, there is a progressive change from external to internal fixation in primary stabilisation of open fractures. This case report describes the treatment for a grade III open Lisfranc fracture-dislocation by use of primary internal fixation and soft-tissue reconstruction. PMID:21706153

  9. Open reduction and internal fixation of radial head fractures.

    PubMed

    King, G J; Evans, D C; Kellam, J F

    1991-01-01

    Open reduction and internal fixation of displaced fractures of the radial head were reviewed in 14 elbows. Follow-up averaged 32 months. The average elbow score for Mason type II fractures was 96.8 points, corresponding to 100% good or excellent results. Average flexion was 142.5 degrees, and the mean fixed flexion deformity was 3.9 degrees. There was no loss in grip strength. An almost normal elbow was the expected result. Good or excellent results were achieved in only 33% of Mason type III fractures treated with open reduction and internal fixation. The average elbow score was 72.9 points, and this was statistically significantly different than the Mason type II fractures (p less than 0.05). An associated elbow dislocation did not affect the results significantly, but was associated with a slightly increased fixed flexion deformity. Fractures may be more comminuted than suggested by plain radiographs, and intraoperative decision making is required in deciding between reconstruction or excision of the radial head. Excellent results were obtained provided an anatomical reduction with stable fixation and early range of motion were achieved. If a stable anatomic reduction cannot be obtained, then alternative treatment methods should be considered. PMID:2023039

  10. [Implant materials for the internal fixation of midfacial fractures].

    PubMed

    Stuck, B A; Heller, T

    2011-11-01

    The material used for osteosynthesis plays a crucial role in the management of facial fractures. Plates need to be flexible enough to be bent and should not be palpable through the skin, while ensuring stable fixation und adequate biocompatibility. Although stainless steel was initially the material of choice, titanium has become the standard material due to its superior biocompatibility. While the explantation of titanium plates and screws appears unnecessary in general, it should be considered in cases of dislocation, cosmetic concerns, pain and infection. Due to their limited initial stability and a potential increase in local complications, resorbable materials based on polymeric lactose are used with caution in midfacial fractures in adults. Our own retrospective study comparing the postoperative complications after fixation of lateral midfacial fractures with titanium and resorbable systems demonstrated a low complication rate for both systems (7-8%) and no statistically significant difference between the two. The appropriate material for fixation should be selected based on the localization and severity of the fracture, the experience of the surgeon as well as on the age and overall condition of the patient. PMID:22012485

  11. A new adhesive technique for internal fixation in midfacial surgery

    PubMed Central

    Endres, Kira; Marx, Rudolf; Tinschert, Joachim; Wirtz, Dieter Christian; Stoll, Christian; Riediger, Dieter; Smeets, Ralf

    2008-01-01

    Background The current surgical therapy of midfacial fractures involves internal fixation in which bone fragments are fixed in their anatomical positions with osteosynthesis plates and corresponding screws until bone healing is complete. This often causes new fractures to fragile bones while drilling pilot holes or trying to insert screws. The adhesive fixation of osteosynthesis plates using PMMA bone cement could offer a viable alternative for fixing the plates without screws. In order to achieve the adhesive bonding of bone cement to cortical bone in the viscerocranium, an amphiphilic bone bonding agent was created, analogous to the dentin bonding agents currently on the market. Methods The adhesive bonding strengths were measured using tension tests. For this, metal plates with 2.0 mm diameter screw holes were cemented with PMMA bone cement to cortical bovine bone samples from the femur diaphysis. The bone was conditioned with an amphiphilic bone bonding agent prior to cementing. The samples were stored for 1 to 42 days at 37 degrees C, either moist or completely submerged in an isotonic NaCl-solution, and then subjected to the tension tests. Results Without the bone bonding agent, the bonding strength was close to zero (0.2 MPa). Primary stability with bone bonding agent is considered to be at ca. 8 MPa. Moist storage over 42 days resulted in decreased adhesion forces of ca. 6 MPa. Wet storage resulted in relatively constant bonding strengths of ca. 8 MPa. Conclusion A new amphiphilic bone bonding agent was developed, which builds an optimizied interlayer between the hydrophilic bone surface and the hydrophobic PMMA bone cement and thus leads to adhesive bonding between them. Our in vitro investigations demonstrated the adhesive bonding of PMMA bone cement to cortical bone, which was also stable against hydrolysis. The newly developed adhesive fixing technique could be applied clinically when the fixation of osteosynthesis plates with screws is impossible. With

  12. [Internal fixation of radial shaft fractures: Anatomical and biomechanical principles].

    PubMed

    Bartoníček, J; Naňka, O; Tuček, M

    2015-10-01

    overhang the bone laterally. In a locking plate with a fixed determined trajectory of screws, the locking screws in the central holes of the plate pass off the shaft centre only through a thin interosseous border (medial position), or screws at the ends of the plate are inserted eccentrically (lateral position). Both these techniques reduce stability of internal fixation. Where the plate overlaps the interosseous border, it is difficult to control the mutual rotation of the two main fragments. A shorter LCP plate increases rigidity of fixation, suppresses bone healing and often leads to non-union.Placement of the plate on the lateral surface of the radius is more beneficial from the viewpoint of the bending and torsion stress. Lateral surface of the radius is a tension site, its distal half is not covered by muscles which eliminates the necessity to release them, the interosseous border is not obscured by plate and all this allows a safe control of rotational position of fragments. A properly pre-bent plate follows the physiological curvature of the lateral surface of the radius. Full tightening of standard screws will fix both main fragments firmly to the apex of plate concavity and increase stability of the internal fixation. Due to the shape of the cross-section of the radial shaft, the trajectory of screws is the longest in case of lateral placement of the plate, which increases rotational stability.We place the plate always in a minimal three-hole length on each main fragment. Transverse two-fragment fractures may be fixed with a 2+2 configuration, i.e. with two screws on each main fragment. Fractures with an inter-fragment or comminuted zone are fixed in the 3+3 mode. More extensive comminutions, defects or segmental fractures require 4 plate holes on each fragment, but not more. When drilling screw holes the drill must be directed into the interosseous border. As a result, the screw has the longest trajectory and the best fixation in the bone. Perforation of the

  13. Wire internal fixation: an obsolete, yet valuable method for surgical management of facial fractures

    PubMed Central

    Bouletreau, Pierre; Konsem, Tarcissus; Traoré, Ibraïma; Coulibaly, Antoine Toua; Ouédraogo, Dieudonné

    2014-01-01

    In some developing countries wire is still widely used in facial fractures internal fixation. This study presents the effectiveness and complications of wire osteosynthesis in a university teaching hospital in Burkina Faso and discusses some of its other benefits and disadvantages. Notes of 227 patients with facial fractures treated by wire internal fixation at department of stomatology and maxillofacial surgery of CHU Souro Sanou, Burkina Faso between 2006 and 2010 are reviewed retrospectively. A satisfactory treatment outcome was recorded in 91.2% of the 227 patients. Complications occurred in 8.8% of the patients who had operative site infection (3.1%), malocclusion (1.8%), sensory disturbance (1.8), facial asymmetry (1.3%), delayed bone union (0.9%) or enophtalmos (0.4%). The overall complications rate was 7.4% after mandibular osteosynthesis, 6.9% after Le Fort osteosynthesis and 6.5% after zygoma osteosynthesis. Post operative infections occurred irrespective to the surgical site. The other complications were more specific to the surgical site. Wire internal fixation may be a reasonable alternative for the surgical treatment of non-comminuted facial fractures and those without bone substance loss, in the setting of limited resources. PMID:25237416

  14. Measures and limits of models of fixation selection.

    PubMed

    Wilming, Niklas; Betz, Torsten; Kietzmann, Tim C; König, Peter

    2011-01-01

    Models of fixation selection are a central tool in the quest to understand how the human mind selects relevant information. Using this tool in the evaluation of competing claims often requires comparing different models' relative performance in predicting eye movements. However, studies use a wide variety of performance measures with markedly different properties, which makes a comparison difficult. We make three main contributions to this line of research: First we argue for a set of desirable properties, review commonly used measures, and conclude that no single measure unites all desirable properties. However the area under the ROC curve (a classification measure) and the KL-divergence (a distance measure of probability distributions) combine many desirable properties and allow a meaningful comparison of critical model performance. We give an analytical proof of the linearity of the ROC measure with respect to averaging over subjects and demonstrate an appropriate correction of entropy-based measures like KL-divergence for small sample sizes in the context of eye-tracking data. Second, we provide a lower bound and an upper bound of these measures, based on image-independent properties of fixation data and between subject consistency respectively. Based on these bounds it is possible to give a reference frame to judge the predictive power of a model of fixation selection. We provide open-source python code to compute the reference frame. Third, we show that the upper, between subject consistency bound holds only for models that predict averages of subject populations. Departing from this we show that incorporating subject-specific viewing behavior can generate predictions which surpass that upper bound. Taken together, these findings lay out the required information that allow a well-founded judgment of the quality of any model of fixation selection and should therefore be reported when a new model is introduced. PMID:21931638

  15. Treatment of Spinal Tuberculosis by Debridement, Interbody Fusion and Internal Fixation via Posterior Approach Only.

    PubMed

    Tang, Ming-xing; Zhang, Hong-qi; Wang, Yu-xiang; Guo, Chao-feng; Liu, Jin-yang

    2016-02-01

    Surgical treatment for spinal tuberculosis includes focal tuberculosis debridement, segmental stability reconstruction, neural decompression and kyphotic deformity correction. For the lesions mainly involved anterior and middle column of the spine, anterior operation of debridement and fusion with internal fixation has been becoming the most frequently used surgical technique for the spinal tuberculosis. However, high risk of structural damage might relate with anterior surgery, such as damage in lungs, heart, kidney, ureter and bowel, and the deformity correction is also limited. Due to the organs are in the front of spine, there are less complications in posterior approach. Spinal pedicle screw passes through the spinal three-column structure, which provides more powerful orthopedic forces compared with the vertebral body screw, and the kyphotic deformity correction effect is better in posterior approach. In this paper, we report a 68-year-old male patient with thoracic tuberculosis who underwent surgical treatment by debridement, interbody fusion and internal fixation via posterior approach only. The patient was placed in prone position under general anesthesia. Posterior midline incision was performed, and the posterior spinal construction was exposed. Then place pedicle screw, and fix one side rod temporarily. Make the side of more bone destruction and larger abscess as lesion debridement side. Resect the unilateral facet joint, and retain contralateral structure integrity. Protect the spinal cord, nerve root. Clear sequestrum, necrotic tissue, abscess of paravertebral and intervertebral space. Specially designed titanium mesh cages or bone blocks were implanted into interbody. Fix both side rods and compress both sides to make the mesh cages and bone blocks tight. Reconstruct posterior column structure with allogeneic bone and autologous bone. Using this technique, the procedures of debridement, spinal cord decompression, deformity correction, bone grafting

  16. Treatment of Spinal Tuberculosis by Debridement, Interbody Fusion and Internal Fixation via Posterior Approach Only

    PubMed Central

    Tang, Ming‐xing; Wang, Yu‐xiang; Guo, Chao‐feng; Liu, Jin‐yang

    2016-01-01

    Surgical treatment for spinal tuberculosis includes focal tuberculosis debridement, segmental stability reconstruction, neural decompression and kyphotic deformity correction. For the lesions mainly involved anterior and middle column of the spine, anterior operation of debridement and fusion with internal fixation has been becoming the most frequently used surgical technique for the spinal tuberculosis. However, high risk of structural damage might relate with anterior surgery, such as damage in lungs, heart, kidney, ureter and bowel, and the deformity correction is also limited. Due to the organs are in the front of spine, there are less complications in posterior approach. Spinal pedicle screw passes through the spinal three‐column structure, which provides more powerful orthopedic forces compared with the vertebral body screw, and the kyphotic deformity correction effect is better in posterior approach. In this paper, we report a 68‐year‐old male patient with thoracic tuberculosis who underwent surgical treatment by debridement, interbody fusion and internal fixation via posterior approach only. The patient was placed in prone position under general anesthesia. Posterior midline incision was performed, and the posterior spinal construction was exposed. Then place pedicle screw, and fix one side rod temporarily. Make the side of more bone destruction and larger abscess as lesion debridement side. Resect the unilateral facet joint, and retain contralateral structure integrity. Protect the spinal cord, nerve root. Clear sequestrum, necrotic tissue, abscess of paravertebral and intervertebral space. Specially designed titanium mesh cages or bone blocks were implanted into interbody. Fix both side rods and compress both sides to make the mesh cages and bone blocks tight. Reconstruct posterior column structure with allogeneic bone and autologous bone. Using this technique, the procedures of debridement, spinal cord decompression, deformity correction, bone

  17. Internal fixation of the sternum in median sternotomy dehiscence.

    PubMed

    Chase, C W; Franklin, J D; Guest, D P; Barker, D E

    1999-05-01

    Sternal dehiscence may be defined as separation of the bony sternum and manubrium following median sternotomy. It may occur at any time postoperatively and has various etiologies. Restoration of sternal integrity in sternal dehiscence is a challenging problem, particularly when associated with deep-seated infection. This report reviews a single-stage technique that virtually eliminates the infected sternotomy wound and provides anatomic reduction and stabilization of the sternum. Complete debridement of infected and/or nonviable soft tissue, bone, and cartilage is followed by pulse irrigation. Parallel stainless steel mandibular reconstruction plates are then placed on each side of the remaining sternum and wired together. One or more transmanubrial compression plates may be added. Bilateral pectoralis major musculocutaneous flap advancement and primary skin closure is performed over two to three closed suction drains. From January of 1994 to July of 1996, this technique was used by the same surgeon in 26 male and 4 female patients aged 43 to 78 years (mean = 61). Indications for the operation were sternal dehiscence with infection (osteomyelitis and/or mediastinitis) in 14 patients and sternal dehiscence without infection in 16 patients. All patients survived to discharge with mean time on the ventilator, intensive care unit length of stay, and postoperative length of stay of 0.7, 2, and 8 days, respectively. Choice and duration of antibiotics were based on culture results and operative findings. Subsequent hardware removal was necessary in one patient for hardware loosening and three patients for late periplate infection. A closed wound was eventually achieved in all 30 patients, and sternal stability was restored in 29 patients. In the management of sternal dehiscence, the described technique of internal fixation can provide anatomic sternal reduction and stabilization, elimination of infection, and wound closure in a single-stage operation. Successful outcomes

  18. Open reduction and internal fixation of displaced clavicle fractures in adolescents.

    PubMed

    Hosalkar, Harish S; Parikh, Gaurav; Bomar, James D; Bittersohl, Bernd

    2012-01-01

    The literature available on patient oriented outcomes of operative management for clavicle fractures in adolescents is fairly limited. The purpose of this study was to analyze the potential of open reduction and internal fixation for displaced mid-shaft clavicle fractures in adolescent patients. We reviewed our series of surgical cases performed in 19 adolescents (mean age: 14.6 years) with displaced unilateral clavicle fractures. Baseline data acquisition included demographic and radiographic variables. A Synthes(®) LCP clavicular plate was utilized for fixation in all cases. Follow-up data included functional outcome assessment using the Quick Disability of Arm, Shoulder, and Hand Questionnaire (DASH), the simple shoulder test (SST) and additional binary questions. At a mean follow-up of 16 months, quick DASH scores were 4.0 (range: 0-35.5) and mean number of positive yes responses on the SST for all operative patients was 11 (range: 9-12). All cases proved complete radiological union at the 3-month follow-up. All patients returned to full athletics at a mean time of 14 weeks (range: 12-17 weeks). Two patients had minimal hypertrophic scars while no patient was noted with keloid formation or neurovascular deficit. One patient complained of implant prominence and occasional symptoms of discomfort at the 15 month follow-up and opted for implant removal. This was successfully performed with uneventful full recovery. All patients were fully satisfied with their choice for surgical intervention. Anatomical reduction with internal fixation and early mobilization of adolescent displaced clavicle fractures remains a viable treatment option with predictable results and no major complications in reliable hands. PMID:22577497

  19. Open reduction and internal fixation of displaced clavicle fractures in adolescents

    PubMed Central

    Hosalkar, Harish S.; Parikh, Gaurav; Bomar, James D.; Bittersohl, Bernd

    2011-01-01

    The literature available on patient oriented outcomes of operative management for clavicle fractures in adolescents is fairly limited. The purpose of this study was to analyze the potential of open reduction and internal fixation for displaced mid-shaft clavicle fractures in adolescent patients. We reviewed our series of surgical cases performed in 19 adolescents (mean age: 14.6 years) with displaced unilateral clavicle fractures. Baseline data acquisition included demographic and radiographic variables. A Synthes® LCP clavicular plate was utilized for fixation in all cases. Follow-up data included functional outcome assessment using the Quick Disability of Arm, Shoulder, and Hand Questionnaire (DASH), the simple shoulder test (SST) and additional binary questions. At a mean follow-up of 16 months, quick DASH scores were 4.0 (range: 0–35.5) and mean number of positive yes responses on the SST for all operative patients was 11 (range: 9–12). All cases proved complete radiological union at the 3-month follow-up. All patients returned to full athletics at a mean time of 14 weeks (range: 12–17 weeks). Two patients had minimal hypertrophic scars while no patient was noted with keloid formation or neurovascular deficit. One patient complained of implant prominence and occasional symptoms of discomfort at the 15 month follow-up and opted for implant removal. This was successfully performed with uneventful full recovery. All patients were fully satisfied with their choice for surgical intervention. Anatomical reduction with internal fixation and early mobilization of adolescent displaced clavicle fractures remains a viable treatment option with predictable results and no major complications in reliable hands. PMID:22577497

  20. Femoral neck shortening after internal fixation of a femoral neck fracture.

    PubMed

    Zielinski, Stephanie M; Keijsers, Noël L; Praet, Stephan F E; Heetveld, Martin J; Bhandari, Mohit; Wilssens, Jean Pierre; Patka, Peter; Van Lieshout, Esther M M

    2013-07-01

    This study assesses femoral neck shortening and its effect on gait pattern and muscle strength in patients with femoral neck fractures treated with internal fixation. Seventy-six patients from a multicenter randomized controlled trial participated. Patient characteristics and Short Form 12 and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were collected. Femoral neck shortening, gait parameters, and maximum isometric forces of the hip muscles were measured and differences between the fractured and contralateral leg were calculated. Variables of patients with little or no shortening, moderate shortening, and severe shortening were compared using univariate and multivariate analyses. Median femoral neck shortening was 1.1 cm. Subtle changes in gait pattern, reduced gait velocity, and reduced abductor muscle strength were observed. Age, weight, and Pauwels classification were risk factors for femoral neck shortening. Femoral neck shortening decreased gait velocity and seemed to impair gait symmetry and physical functioning. In conclusion, internal fixation of femoral neck fractures results in permanent physical limitations. The relatively young and healthy patients in our study seem capable of compensating. Attention should be paid to femoral neck shortening and proper correction with a heel lift, as inadequate correction may cause physical complaints and influence outcome. PMID:23823040

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

    PubMed Central

    Sakai, Rina; Matsuura, Terumasa; Tanaka, Kensei; Nakao, Masaki

    2014-01-01

    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. PMID:25136691

  2. Distal Femoral Osteotomy in Genovalgum: Internal Fixation with Blade Plate Versus Casting

    PubMed Central

    Makhmalbaf, Hadi; Moradi, Ali; Ganji, Saeid

    2014-01-01

    Background: To compare the results of two different ways of distal femoral osteotomy stabilization in patients suffering from genuvalgum: internal fixation with plate, and casting. Methods: 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. Results: 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. Conclusions: 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. PMID:25692152

  3. A biomechanical comparison of internal fixation techniques for ankle arthrodesis.

    PubMed

    Clifford, Craig; Berg, Scott; McCann, Kevin; Hutchinson, Byron

    2015-01-01

    The purpose of the present study was to compare the primary bending stiffness characteristics of 5 different ankle arthrodesis fixation techniques: 3 compression screws, an anterior locking plate, a lateral locking plate, an anterior locking plate with a compression screw, and a lateral locking plate with a compression screw. A total of 25 full-scale anatomic models consisting of fourth-generation composite tibiae and tali were tested using an Instron 4505 Universal Testing System. We hypothesized that the use of a compression screw with a locking plate would add considerable stiffness to the fixation construct compared with the use of a locking plate alone. The data have shown that an anterior or lateral plate with a compression screw provides significantly greater stiffness than both a plate and 3 compression screws used individually. No significant difference was seen between the anterior plate with a compression screw and the lateral plate with a compression screw. No significant differences were found among the use of an anterior plate, a lateral plate, or 3 compression screws. We have concluded that when using a locking plate in an anterior or lateral configuration, the addition of a compression screw will considerably increase the primary bending stiffness of ankle arthrodesis. PMID:25116232

  4. Functional outcome after successful internal fixation versus salvage arthroplasty of patients with a femoral neck fracture

    PubMed Central

    Zielinski, Stephanie M.; Keijsers, Noël L.; Praet, Stephan F.E.; Heetveld, Martin J.; Bhandari, Mohit; Wilssens, Jean Pierre; Patka, Peter; Van Lieshout, Esther M.M.

    2014-01-01

    Objectives To determine patient independency, health-related and disease-specific quality of life (QOL), gait pattern, and muscle strength in patients after salvage arthroplasty for failed internal fixation of a femoral neck fracture. Design Secondary cohort study to a randomized controlled trial. Setting Multicenter trial in the Netherlands, including 14 academic and non-academic hospitals Patients Patients after salvage arthroplasty for failed internal fixation of a femoral neck fracture were studied. A comparison was made with patients who healed uneventfully after internal fixation. Intervention None (observatory study) Main outcome measurements Patient characteristics, SF-12, and WOMAC scores were collected. Gait parameters were measured using plantar pressure measurement. Maximum isometric forces of the hip muscles were measured using a handheld dynamometer. Differences between the fractured and contralateral leg were calculated. Groups were compared using univariate analysis. Results Of 248 internal fixation patients (median age 72 years), salvage arthroplasty was performed in 68 patients (27%). Salvage arthroplasty patients had a significantly lower WOMAC score (median 73 versus 90, P=0.016) than patients who healed uneventfully after internal fixation. Health-related QOL (SF-12) and patient independency did not differ significantly between the groups. Gait analysis showed a significantly impaired progression of the center of pressure in the salvage surgery patients (median ratio −8.9 versus 0.4, P=0.013) and a significant greater loss of abduction strength (median −25.4 versus −20.4 N, P=0.025). Conclusion Despite a similar level of dependency and QOL, salvage arthroplasty patients have inferior functional outcome than patients who heal after internal fixation of a femoral neck fracture. PMID:24835623

  5. COMPARISON OF VOLUMES OCCUPIED BY DIFFERENT INTERNAL FIXATION DEVICES FOR FEMORAL NECK FRACTURES

    PubMed Central

    Lauxen, Daniel; Schwartsmann, Carlos Roberto; Silva, Marcelo Faria; Spinelli, Leandro de Freitas; Strohaecker, Telmo Roberto; Souza, Ralf Wellis de; Zimmer, Cinthia Gabriely; Boschin, Leonardo Carbonera; Gonçalves, Ramiro Zilles; Yépez, Anthony Kerbes

    2015-01-01

    Objective: The objective of this paper is to measure the volume occupied by the most widely used internal fixation devices for treating femoral neck fractures, using the first 30, 40 and 50 mm of insertion of each screw as an approximation. The study aimed to observe which of these implants caused least bone aggression. Methods: Five types of cannulated screws and four types of dynamic hip screws (DHS) available on the Brazilian market were evaluated in terms of volume differences through water displacement. Results: Fixation with two cannulated screws presented significantly less volume than shown by DHS, for insertions of 30, 40 and 50 mm (p=0.01, 0.012 and 0.013, respectively), fixation with three screws did not show any statistically significant difference (p= 0.123, 0.08 and 0.381, respectively) and fixation with four cannulated screws presented larger volumes than shown by DHS (p=0.072, 0.161 and 0.033). Conclusions: Fixation of the femoral neck with two cannulated screws occupied less volume than DHS, with a statistically significant difference. The majority of screw combinations did not reach statistical significance, although fixation with four cannulated screws presented larger volumes on average than those occupied by DHS. PMID:27047886

  6. Semi-automatic customization of internal fracture fixation plates.

    PubMed

    Musuvathy, Suraj; Azernikov, Sergei; Fang, Tong

    2011-01-01

    A new method for customization of fixation plates for repairing bone fractures is proposed. Digital models of plates are typically available as CAD models that contain smooth analytic geometry representations including NURBS. With the existing pre-operative planning solutions, these models are converted to polygonal meshes and adapted manually to the patient's bone geometry by the user. Based on the deformed model, physical bending is then performed by the surgeon in operating room. With the proposed approach, CAD models are semi-automatically adapted using NURBS to generate customized plates that conform to the desired region of the bone surface of patients. This enables an efficient and accurate approach that is also computationally suitable for interactive planning applications. Moreover, the patient-specific customized plates can then be produced directly from the adapted CAD models with a standard CNC machine before surgery. This may dramatically reduce time spent in OR, improve precision of the procedure and as a result improve the patient's outcome. PMID:22254380

  7. Impact response and simulation of damaged ulna with internal fixation.

    PubMed

    Coates, Cameron; Goeser, Priya; Coates-Clark, Camille; Jenkins, Mark

    2012-07-01

    The objectives of this work were to explore a methodology that combines static and dynamic finite element (FE) analysis, linear elastic fracture mechanics (LEFM) and experimental methods to investigate a worst-case scenario in which a previously damaged bone plate system is subjected to an impact load. Cadaver ulnas with and without midshaft dynamic compression plates are subjected to a static three-point bend test and loaded such that subcritical crack growth occurs as predicted by a hybrid method that couples LEFM and static FE. The plated and unplated bones are then unloaded and subsequently subjected to a midshaft transverse impact test. A dynamic strain-based FE model is also developed to model the midshaft transverse impact test. The average value of the impact energy required for failure was observed to be 10.53% greater for the plated set. There appears to be a trade-off between impact damage and impact resistance when ulnas are supported by fixation devices. Predictions from the dynamic FE model are shown to corroborate inferences from the experimental approach. PMID:22084055

  8. Evaluation of Bite Force After Open Reduction and Internal Fixation Using Microplates

    PubMed Central

    Kumar, S Tharani; Saraf, Saurabh; Devi, S Prasanna

    2013-01-01

    The primary aim of this study is to determine maximum bite force in molar and incisor regions of healthy individuals, to evaluate the bite force after open reduction and internal fixation of mandibular fractures using micro plates, for a period of up to 6 weeks and to determine the rate of recovery of maximum bite force in an Indian population. PMID:24910656

  9. Internal fixation treatments for intertrochanteric fracture: a systematic review and meta-analysis of randomized evidence

    PubMed Central

    Yu, Jiajie; Zhang, Chao; Li, Ling; Kwong, Joey S. W.; Xue, Li; Zeng, Xiantao; Tang, Li; Li, Youping; Sun, Xin

    2015-01-01

    The relative effects of internal fixation strategies for intertrochanteric fracture after operation remain uncertain. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to address this important issue. We searched PubMed, EMBASE and CENTRAL for RCTs that compared different internal fixation implants in patients with intertrochanteric fracture at 6-month follow-up or longer. We ultimately included 43 trials enrolling 6911 patients; most trials were small in sample sizes and events. Their risk of bias was generally unclear due to insufficient reporting. Because of these, no statistically significant differences were present from most of the comparisons across all the outcomes, and no definitive conclusions can be made. However, a number of trials compared two commonly used internal fixation strategies, gamma nail (GN) and sliding hip screw (SHS). There is good evidence suggesting that, compared to SHS, GN may increase the risk of cut out (OR = 1.87, 95% CI, 1.08 to 3.21), re-operation (OR = 1.61, 95% CI, 1.02 to 2.53), intra-operative (OR = 3.14, 95% CI, 1.34 to 7.35) and later fractures (OR = 3.67, 95% CI, 1.37 to 9.83). Future randomized trials or observational studies that are carefully designed and conducted are warranted to establish the effects of alternative internal fixation strategies for intertrochanteric fracture. PMID:26657600

  10. Internal polarization limits coronagraph contrast

    NASA Astrophysics Data System (ADS)

    Breckinridge, James Bernard; Lam, Wai Sze T.; Chipman, Russell A.

    2015-08-01

    The performance of exoplanet imaging coronagraphs is limited by internal polarization. The point spread function (PSF) of these systems is determined by the details of the opto-mechanical layout selected to package the system and by the highly reflective metal thin films needed to maintain high optical system transmittance. To obtain the high contrast levels needed for terrestrial exoplanet science requires a comprehensive understanding of the vector electromagnetic wave from the source through the system. The literature contains many studies of polarization transmissivity of telescopes and instruments for the purpose of photo-polarimetry. Here we report for the first time the effects of polarization on high-performance image quality.We modeled a typical 2.4-meter Cassegrain telescope system with one 90-degree fold mirror and analyzed the system for polarization aberrations.We find: 1. The image plane irradiance distribution is the linear superposition of four PSF images: One for each of the two orthogonal polarizations and one for each of two cross-product polarization terms. 2. The PSF image is brighter by 9% for one polarization component compared to its orthogonal state. 3. The image of the PSF for orthogonal components are shifted across the focal plane with respect to each other, causing the PSF image for astronomical sources (polarized or unpolarized) to become slightly elongated (elliptical) with a centroid separation of about 0.6 masec. 4. The orthogonally polarized components of unpolarized sources contain different wavefront aberrations, which are separated by approximately 32 milliwaves. This implies that a wavefront correction system cannot optimally correct the aberrations for all polarizations simultaneously. 5. The polarization aberrations couple small parts (~1E-5) of each polarization component of the light into the orthogonal polarization to create highly distorted secondary, or “ghost” PSF image.. The radius of the spatial extent of the 90

  11. Technique of Open Reduction and Internal Fixation of Comminuted Proximal Humerus Fractures With Allograft Femoral Head Metaphyseal Reconstruction.

    PubMed

    Parada, Stephen A; Makani, Amun; Stadecker, Monica J; Warner, Jon J P

    2015-10-01

    Proximal humerus fractures are common injuries that can require operative treatment. Different operative techniques are available, but the hallmark of fixation for 3- and 4-part fractures is a locking-plate-and-screw construct. Despite advances in this technology, obtaining anatomical reduction and fracture union can be difficult, and complications (eg, need for revision) are not uncommon. These issues can be addressed by augmenting the fixation with an endosteally placed fibular allograft. Although biomechanical and clinical results have been good, the technique can lead to difficulties in future revision to arthroplasty, a common consequence of failed open reduction and internal fixation. The technique described, an alternative to placing a long endosteal bone graft, uses a trapezoidal, individually sized pedestal of allograft femoral head to facilitate the reduction and healing of the humeral head and tuberosity fragments in a displaced 3- or 4-part fracture of the proximal humerus. It can be easily incorporated with any plate-and-screw construct and does not necessitate placing more than 1 cm of bone into the humeral intramedullary canal, limiting the negative effects on any future revision to arthroplasty. PMID:26447409

  12. The biocompatibility of materials for internal fixation of fractures.

    PubMed

    Brown, S A; Mayor, M B

    1978-01-01

    Surgically produced fractures of rabbit tibiae were internally stabilized with intramedullary rods of stainless steel (316LVM), titanium (6A1,4V), polyacetal (Delrin), and polyamide (Nylon 101). Periodic radiographs were taken until sacrifice at 16 weeks after fracture. Structural properties of the tibiae were determined in torsion with the rods in situ, and then the tissue was prepared for histology or microradiography. The results demonstrated that fracture remodeling was adversely affected by the metal rods. New bone was seen to have formed over the ends of the metal rods, and cortical bone resorption was observed in the fracture region, suggestive of transfer of mechanical stress to the rods, resulting in stress shielding of the diaphysis. Negligible osseous response to the polymeric rods was observed; fracture callus remodeling was extensive. The torsional test results demonstrated that fractures with polymeric rods were significantly stronger and tougher than those with metallic rods. With the exception of titanium, the strength of healed fractures was inversely related to the elastic moduli of the implant materials. PMID:632318

  13. An electronically instrumented internal fixator for the assessment of bone healing

    PubMed Central

    Kowald, B.; Seide, K.; Aljudaibi, M.; Faschingbauer, M.; Juergens, C.; Gille, J.

    2016-01-01

    Objectives The monitoring of fracture healing is a complex process. Typically, successive radiographs are performed and an emerging calcification of the fracture area is evaluated. The aim of this study was to investigate whether different bone healing patterns can be distinguished using a telemetric instrumented femoral internal plate fixator. Materials and Methods An electronic telemetric system was developed to assess bone healing mechanically. The system consists of a telemetry module which is applied to an internal locking plate fixator, an external reader device, a sensor for measuring externally applied load and a laptop computer with processing software. By correlation between externally applied load and load measured in the implant, the elasticity of the osteosynthesis is calculated. The elasticity decreases with ongoing consolidation of a fracture or nonunion and is an appropriate parameter for the course of bone healing. At our centre, clinical application has been performed in 56 patients suffering nonunion or fracture of the femur. Results A total of 39 cases of clinical application were reviewed for this study. In total, four different types of healing curves were observed: fast healing; slow healing; plateau followed by healing; and non-healing. Conclusion The electronically instrumented internal fixator proved to be valuable for the assessment of bone healing in difficult healing situations. Cost-effective manufacturing is possible because the used electronic components are derived from large-scale production. The incorporation of microelectronics into orthopaedic implants will be an important innovation in future clinical care. Cite this article: B. Kienast, B. Kowald, K. Seide, M. Aljudaibi, M. Faschingbauer, C. Juergens, J. Gille. An electronically instrumented internal fixator for the assessment of bone healing. Bone Joint Res 2016;5:191–197. DOI: 10.1302/2046-3758.55.2000611. PMID:27226357

  14. Enhancement of Apoptosis by Titanium Alloy Internal Fixations during Microwave Treatments for Fractures: An Animal Study

    PubMed Central

    Zhang, Lina; Ye, Dongmei; Feng, Xianxuan; Fu, Tengfei; Bai, Yuehong

    2015-01-01

    Objective Microwaves are used in one method of physical therapy and can increase muscle tissue temperature which is useful for improving muscle, tendon and bone injuries. In the study, we sought to determine whether titanium alloy internal fixations influence apoptosis in tissues subjected to microwave treatments at 2,450 MHz and 40 W during the healing of fractures because this issue is not yet fully understood. Methods In this study, titanium alloy internal fixations were used to treat 3.0-mm transverse osteotomies in the middle of New Zealand rabbits’ femurs. After the operation, 30-day microwave treatments were applied to the 3.0 mm transverse osteotomies 3 days after the operation. The changes in the temperatures of the muscle tissues in front of the implants or the 3.0 mm transverse osteotomies were measured during the microwave treatments. To characterize the effects of titanium alloy internal fixations on apoptosis in the muscles after microwave treatment, we performed TUNEL assays, fluorescent real-time (quantitative) PCR, western blotting analyses, reactive oxygen species (ROS) detection and transmission electron microscopy examinations. Results The temperatures were markedly increased in the animals with the titanium alloy implants. Apoptosis in the muscle cells of the implanted group was significantly more extensive than that in the non-implanted control group at different time points. Transmission electron microscopy examinations of the skeletal muscles of the implanted groups revealed muscular mitochondrial swelling, vacuolization. ROS, Bax and Hsp70 were up-regulated, and Bcl-2 was down-regulated in the implanted group. Conclusion Our results suggest that titanium alloy internal fixations caused greater muscular tissue cell apoptosis following 2,450 MHz, 40 W microwave treatments in this rabbit femur fracture models. PMID:26132082

  15. Biomechanical testing of the LCP--how can stability in locked internal fixators be controlled?

    PubMed

    Stoffel, Karl; Dieter, Ulrich; Stachowiak, Gwidon; Gächter, André; Kuster, Markus S

    2003-11-01

    New plating techniques, such as non-contact plates, have been introduced in acknowledgment of the importance of biological factors in internal fixation. Knowledge of the fixation stability provided by these new plates is very limited and clarification is still necessary to determine how the mechanical stability, e.g. fracture motion, and the risk of implant failure can best be controlled. The results of a study based on in vitro experiments with composite bone cylinders and finite element analysis using the Locking Compression Plate (LCP) for diaphyseal fractures are presented and recommendations for clinical practice are given. Several factors were shown to influence stability both in compression and torsion. Axial stiffness and torsional rigidity was mainly influenced by the working length, e.g. the distance of the first screw to the fracture site. By omitting one screw hole on either side of the fracture, the construct became almost twice as flexible in both compression and torsion. The number of screws also significantly affected the stability, however, more than three screws per fragment did little to increase axial stiffness; nor did four screws increase torsional rigidity. The position of the third screw in the fragment significantly affected axial stiffness, but not torsional rigidity. The closer an additional screw is positioned towards the fracture gap, the stiffer the construct becomes under compression. The rigidity under torsional load was determined by the number of screws only. Another factor affecting construct stability was the distance of the plate to the bone. Increasing this distance resulted in decreased construct stability. Finally, a shorter plate with an equal number of screws caused a reduction in axial stiffness but not in torsional rigidity. Static compression tests showed that increasing the working length, e.g. omitting the screws immediately adjacent to the fracture on both sides, significantly diminished the load causing plastic

  16. Result of Internal Fixation for Stable Femoral Neck Fractures in Elderly Patients

    PubMed Central

    Min, Byung-Woo; Bae, Ki-Cheor; Lee, Si-Wuk; Lee, Seok-Jung; Choi, Jung-Hoon

    2016-01-01

    Purpose This study was conducted to evaluate the results of internal fixation for stable femoral neck fractures occurring in patients over 65 years old. Materials and Methods Between 2008 and 2014, we evaluated 25 patients over 65 years old with Garden type 1 and 2 femoral neck fractures that were treated with internal fixation after a minimum follow up of 1 year. There were 5 males and 20 females and the average age was 72.3 years (range, 65-84 years) at the time of surgery. Fracture site union, horizontal shortening and complications were evaluated as radiographic parameters and change of walking ability (as measured using Koval walking ability score) was investigated as a clinical parameter. Results Union of fracture site was achieved in 24 out of the 25 cases (96.0%). The average length of horizontal shortening was 6.5 mm (range, 0.2-19.7 mm). At final follow up, 3 cases experienced complications: nonunion (n=1), avascular necrosis (n=1), and subtrochanteric fracture after minor trauma (n=1). Walking ability decreased an average of 1 step at the final follow up. Conclusion Internal fixation for stable femoral neck fractures occurring in patients over 65 years showed satisfactory union rates. However, care should be taken with this technique given the possibility of decreased walking ability resulting from horizontal shortening.

  17. [Acetabular fractures in the elderly. Outcome of open reduction and internal fixation].

    PubMed

    Tosounidis, G; Culemann, U; Bauer, M; Holstein, J H; Garcia, P; Kurowski, R; Pizanis, A; Aghayev, E; Pohlemann, T

    2011-08-01

    The aim of this study was to analyze the clinical outcome and incidence of hip arthritis in elderly patients with acetabular fractures. Because of poor bone quality in the elderly, even a low-energy trauma may lead to an acetabular fracture. An anatomical reconstruction of the acetabulum is necessary to achieve sufficient stability also for a potential hip arthroplasty. So far, there is very limited information on the outcome of acetabular fractures in the elderly. During a period of 6 years (2001-2006), 48 patients older than 60 years were admitted to our department with an acetabular fracture. Thirty-nine patients were treated operatively and nine patients non-operatively. Twenty-nine operatively treated patients were followed up. Nineteen of them were assessed using EQ-5D, SF-12 and Merle d'Aubigné questionnaires in addition to their clinical examination. Ten other surgical patients were only examined using the questionnaires. Of the 29 patients that were followed up, 5 underwent total hip arthroplasty due to secondary post-traumatic hip arthritis after open reduction and internal fixation (ORIF). The range of motion of the operated hip was comparable to that of the non-operated contralateral side. However, the internal rotation was found to be slightly decreased at the operated side when compared to the non-operated contralateral side. Merle d'Aubigné score and physical and mental SF-12 score components as well as quality of life were better in patients treated with ORIF compared to those patients that were treated by secondary hip arthroplasty. Regarding the different treatment strategies (ORIF vs primary hip arthroplasty vs non-operative treatment) of acetabular fractures in the elderly, data from the literature are conflicting. Our results indicate that ORIF represents a good treatment option for acetabular fractures in the elderly. In patients that did not develop secondary hip arthritis, a good clinical outcome and quality of life was documented. PMID

  18. Seasonally dependent iron limitation of nitrogen fixation in tropical forests of karst landscapes

    NASA Astrophysics Data System (ADS)

    Winbourne, J. B.; Brewer, S.; Houlton, B. Z.

    2015-12-01

    Limestone tropical forests in karst topography are one of the most poorly studied ecosystems on Earth, and has been substantially cleared by human activities throughout much of Central America. This ecosystem is noted for its high level of plant productivity, biomass, endemism and biological diversity compared to nearby neighboring tropical forests on volcanic rock substrates (Brewer et al. 2002). A question remains as to how limestone tropical forests are able to maintain the high nutrient demands of plant photosynthesis and tree biomass growth. Here, we demonstrate that rates of nitrogen (N) fixation are higher in limestone versus volcanic soil substrates, with direct evidence for the emergence of seasonally dependent iron limitation of N fixation in limestone tropical forest. N fixation rates showed a three-fold increase in response to iron additions, especially during the wet season when N demands of the forest trees are highest. In contrast, adjacent forests growing on the more classical acidic volcanic soils showed no response to iron or other nutrient additions. Biologically available pools of iron were exceedingly low in the limestone forest site, consistent with the complexation of iron under high pH conditions. Biological acquisition of iron, as measured by the concentration of iron chelating compounds (i.e. siderophores), provided additional evidence for iron limitation of microbial processes in limestone tropical forests, where concentrations were six times higher than those at the volcanic site. Our results suggest that the functioning of limestone tropical forest is strongly regulated by interactions between iron, soil pH, and N cycling.

  19. Treatment of Edentulous Mandibular Fractures with Rigid Internal Fixation: Case Series and Literature Review

    PubMed Central

    Franciosi, Edgardo; Mazzaro, Eduardo; Larranaga, Juan; Rios, Alfredo; Picco, Pedro; Figari, Marcelo

    2014-01-01

    The aim of the study is to analyze the effectiveness of rigid internal fixation (RIF) for treating edentulous mandibular fractures. Because of the low incidence of fractures in edentulous mandible, there is no consensus of the optimal treatment for it. This study included all edentulous patients with mandibular fracture diagnosis, who were treated with internal fixation at the Hospital Italiano de Buenos Aires from November 1991 to July 2011. Data such as age, gender, etiology and location of fracture, surgical approach, type of osteosynthesis used, and postoperative complications were analyzed. A total of 18 patients, 76.2 years mean age, 12 females (66.6%), presented a total of 35 mandibular fractures. The mandibular body was the most common localization of the fractures. Twenty-five fractures received surgical treatment with RIF, mainly approached extraorally. Reconstruction plates were the most common type of fixation used. Fracture reduction was considered satisfactory in 96.5%, with 22.2% of complications and 11.1% of reoperations needed. Open reduction and RIF demonstrated to be a reliable method for treating edentulous mandibular fractures. Nevertheless, there is lack of high-level recommendation publication to support this. PMID:24624255

  20. Open Reduction and Internal Fixation of Intraarticular Fractures of the Humerus: Evaluation of 33 Cases

    PubMed Central

    Mardanpour, Keykhosro; Rahbar, Mahtab

    2013-01-01

    Background Standard treatment of type C elbow fractures is open reduction and internal fixation using reconstruction plates and pins. Objectives The aim of this study was to evaluate the functional outcome following internal fixation of intraarticular fractures of the distal humerus (AO Type C) with a minimum follow-up of three years. A retrospective evaluation was undertaken. Patients and Methods Thirty-three patients (28 males, 5 females; mean age 34.3years) type C elbow fractures were treated and observed over a period of three years. Six fractures were open and 27 closed; causes were falls (7 cases), traffic accidents (22 cases) and altercation (4 cases). All operations were performed using a posterior approach with an olecranon osteotomy. Mean duration of follow-up was 18 months (range 6–36). Mean duration of fracture healing was 2.3 months (range 2–4). Functional outcomes were assessed by Jupiter criteria. Results Excellent results were found in 69.7% (23 cases), very good reaults and good results were found in the remaining 30.3% (10 cases). Three of 33 patients 9% (3 cases) presented postoperative complications. No patient exhibited symptoms of ulnar nerve injury following surgery. One patient had cubitusvarus deformities and one case had heterotopic ossification. One patient had malunion and one case had deep infection. Conclusions Complications were minimal and outcomes were satisfactory in patients with type C distal humerus fractures who underwent bilateral plate fixation via a posterior approach. PMID:24350136

  1. Causes and managements of postoperative complications after degenerative scoliosis treatments with internal fixation

    PubMed Central

    Yang, Yong-Hong; Zheng, Jie; Lou, Shu-Liang

    2014-01-01

    Objective: To investigate the causes and managements of early postoperative complications of degenerative scoliosis (DS) treated with internal pedicle screw fixation. Methods: From Jan 2000 to Apr 2013, 325 DS patients treated with internal pedicle screw fixation in our hospital were retrospectively involved. The categories, causes, managements and outcomes of early postoperative complications were statistically analyzed. Results: Early postoperative complications occurred in 10.76% of the patients including 16 cases of lower limb numb or pain, 6 cases of decreased lower limb sensitivity and motor functions, which accounted for 62.86% of all complications, followed by incision infections (4/35, 11.43%) and rare cases of cerebrospinal fluid leakage, cardiac and renal inadequacy, urinary system and pulmonary infections. The incidence of overall complications (19.79%, p = 0.001) and nerve injuries (11.46%, p = 0.000) were significantly higher in long-segment than in short-segment fixations. Improper screw implanting, over correction of scoliosis and insufficient blood supply of the spinal cord during operation were risk factors for early postoperative complications and most of them were cured by anti-infection medication, incision dressing change, nerve nourishment, adjusting the screws and anti-osteoporosis treatments within 6 months after surgery. Only three cases with severe nerve injury did not improve until the 6 months postoperative follow-up. Conclusions: Most of the postoperative complications in our DS patients disappeared within 6 months after surgery and more than half of complications were nerve injuries. PMID:25550945

  2. Nitrogen limitation and nitrogen fixation during alkane biodegradation in a sandy soil.

    PubMed Central

    Toccalino, P L; Johnson, R L; Boone, D R

    1993-01-01

    We investigated nutrient limitations during hydrocarbon degradation in a sandy soil and found that fixed nitrogen was initially a limiting nutrient but that N limitation could sometimes be overcome by N2 fixation. Hydrocarbon biodegradation was examined in an unsaturated sandy soil incubated aerobically at 20 degrees C with propane or butane and various added nutrients. Propane and butane degradation proceeded similarly during the first 3 months of incubation. That is, bacteria in soil amended with N oxidized these hydrocarbons more rapidly than in controls without nutrient additions or in soil with added phosphate or trace minerals. Both propane- and butane-amended soil apparently became N limited after the initial available inorganic N was utilized, as indicated by a decrease in the rates of hydrocarbon degradation. After 3 months, propane and butane degradation proceeded differently. Bacteria in propane-degrading soil apparently remained N limited because propane degradation rates stayed low unless more N was added. In contrast, bacteria in butane-degrading soil appeared to overcome their N limitation because butane degradation rates later increased regardless of whether more N was added. Analyses of total N and acetylene reduction assays supported this apparent surplus of N in butane-amended soil. Total N was significantly (P < 0.01) higher in soil incubated with butane and no N amendments than in soil incubated with propane, even when the latter was amended with N. Acetylene reduction occurred only in butane-amended soil. These results indicate that N2 fixation occurred in butane-amended soil but not in propane-amended soil. PMID:8215369

  3. Bioburden after S. aureus Inoculation in Type-1 Diabetic Rats Undergoing Internal Fixation

    PubMed Central

    Brown, Nga L.; Rose, Michael B.; Blueschke, Gert; Cho, Eugenia H.; Schoenfisch, Mark H.; Erdmann, Detlev; Klitzman, Bruce

    2014-01-01

    Fracture stabilization in the diabetic patient is associated with higher complication rates, particularly infection and impaired wound healing, which can lead to major tissue damage, osteomyelitis, and higher amputation rates. With an increasing prevalence of diabetes and an aging population, the risks of infection of internal fixation devices are expected to grow. Although numerous retrospective clinical studies have identified a relationship between diabetes and infection, currently there are few animal models that have been used to investigate postoperative surgical site infections associated with internal fixator implantation and diabetes. We therefore refined the protocol for inducing hyperglycemia and compared the bacterial burden in controls to pharmacologically induced type-1 diabetic rats after undergoing internal fracture plate fixation and Staphylococcus aureus surgical site inoculation. Using an initial series of streptozotocin doses, followed by optional additional doses to reach a target blood glucose range of 300–600 mg/dl, we reliably induced diabetes in 100% of the rats (n=16) who maintained a narrow hyperglycemic range 14 days after onset of diabetes (466 ± 16 mg/dl, mean ± SEM; coefficient of variation = 0.15). With respect to our primary endpoint, we quantified a significantly higher infectious burden in inoculated diabetic animals (median 3.2 × 1010 CFU/mg dry tissue) when compared to inoculated non-diabetics (7.2 × 104 CFU/mg dry tissue). These data support our hypothesis that uncontrolled diabetes adversely affects the immune system’s ability to clear S. aureus associated with internal hardware. PMID:25158718

  4. Posterior internal fixation plus vertebral bone implantation under navigational aid for thoracolumbar fracture treatment

    PubMed Central

    ZHOU, WEI; KONG, WEIQING; ZHAO, BIZHEN; FU, YISHAN; ZHANG, TAO; XU, JIANGUANG

    2013-01-01

    The aim of this study was to investigate the method of posterior thoracolumbar vertebral pedicle screw reduction and fixation combined with vertebral bone implantation via the affected vertebral body under navigational aid for the treatment of thoracolumbar fractures. The efficacy of the procedure was also measured. Between June 2005 and March 2011, posterior thoracolumbar vertebral pedicle screw reduction and fixation plus artificial bone implantation via the affected vertebral pedicle under navigational aid was used to treat 30 patients with thoracolumbar fractures, including 18 males and 12 females, ranging in age from 21 to 57 years. Compared with the values prior to surgery, intraspinal occupation, vertebral height ratio and Cobb angle at the follow-up were significantly improved. At the long-term follow-up, the postoperative Cobb angle loss was <1° and the anterior vertebral body height loss was <2 mm. Posterior thoracolumbar vertebral pedicle screw reduction and fixation combined with vertebral bone implantation via the affected vertebral body under navigational aid may increase the accuracy and safety of surgery, and it is an ideal method of internal implantation. Bone implantation via the affected vertebral body may increase vertebral stability. PMID:23935737

  5. Open reduction and internal fixation of posterior pilon fractures with buttress plate

    PubMed Central

    Chen, Da-wei; Li, Bing; Aubeeluck, Ashwin; Yang, Yun-feng; Zhou, Jia-qian; Yu, Guang-rong

    2014-01-01

    Objective: Posterior pilon fractures are rare injuries and have not yet gained well recognition. The purpose of this study was to present the treatment outcome for patients with posterior pilon fractures treated with buttress plate. Method: In this retrospective study we identified patients with posterior pilon fractures of the distal tibia who had undergone open reduction and internal fixation at our institute. Between January 2007 and December 2009, 10 patients (mean age, 46.5 years) who had undergone buttress plating via either a posterolateral approach or a dual posterolateral-posteromedial approach, were selected. All 10 patients were available for follow-up. The clinical outcome was evaluated with the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and the visual analogue scale (VAS). The radiological evaluation was performed using the osteoarthritis-score (OA-score). Results: Satisfactory reduction and stable fixation were accomplished in all patients. At a mean follow-up of 36.2 months, all patients had good radiological results and showed satisfactory clinical recovery. The mean AOFAS sore was 87.8, the mean OA-score was 0.6, and the mean VAS scores during rest, active motion, and weight-bearing walking were 0.6, 0.8, and 1.4, respectively. Conclusion: Buttress plating for posterior pilon fractures gave satisfactory clinical outcomes. It also ensured rigid fixation which in turn enabled earlier postoperative mobilization. Level of Evidence IV, Retrospective Study. PMID:24644421

  6. Assessment of nutrient limitation on the primary production and N2 fixation across the tropical Atlantic

    NASA Astrophysics Data System (ADS)

    Ridame, C.; Mills, M. M.; Davey, M.; Laroche, J.; Geider, R.

    2003-04-01

    In the surface layer of the Tropical North Atlantic, Saharan dust inputs, as a source of iron and phosphate, might preferentially stimulate the growth of diazotrophs. The availability of iron, essential for the synthesis of the nitrogenase enzyme, and/or phosphorus through dust inputs is suspected to impose additional control on N_2 fixation in these waters chronically low in dissolved inorganic nitrogen. Here, we present results from the cruise M-55 (October--November 2002, SOLAS Program) in the tropical Atlantic (11^oN) between Curacao and Cameroon that address this hypothesis. The studied area was particularly interesting because it is characterized by a nutrient gradient from oligotrophic waters (Caribbean Sea) to upwelling dominated regions (NW Africa) and is also subject to a strong lateral gradient of inputs from Saharan mineral aerosol. Using trace metal clean methods, nutrient addition bioassays were used to asses which nutrient (N, P, and Fe) most likely limits of phytoplankton biomass, primary productivity and dinitrogen fixation in incubation experiments along the transect. An additional Saharan dust treatment, considered as a proxy for Saharan aerosol, was used to simulate an atmospheric Saharan dust input into the surface layer.

  7. The history of internal fixation of proximal femur fractures Ernst Pohl-the genius behind.

    PubMed

    Bartoníček, Jan; Rammelt, Stefan

    2014-11-01

    The most frequently used implants for internal fixation of proximal femoral fractures are currently the dynamic hip screw and the intramedullary hip nail. However, little has been written about one of the pioneers in this field, a German genius, the designer Ernst Pohl (1876-1962). Without his involvement the concepts of intramedullary nailing coined by Gerhard Küntscher, Richard Maatz and other surgeons could hardly have been implemented. Through his achievements Pohl has rightly merited his pre-eminent position in the history of bone surgery. This article outlines the extraordinary contribution of Ernst Pohl to the development of skeletal surgery and radiology, as well as other medical disciplines. PMID:24687268

  8. Sphagnum N and P Stoichiometry Indicates P-limitation on N2 Fixation in Ombrotrophic Bogs

    NASA Astrophysics Data System (ADS)

    Zivkovic, T.; Moore, T. R.; Disney, K.

    2015-12-01

    Biological N2 fixation is an important N input in ombrotrophic, nutrient poor and Sphagnum dominated bogs. As an energetically costly process, by which each N2 molecule is fixed to a cost of 16ATP molecules, N2 fixation might be P limited process. In this study we tested whether moss P and N concentrations, and N:P ratios could explain N2 fixation in the top 6cm photosynthetically active Sphagnum moss across eight ombrotrophic bogs along south-north geographical gradient in Ontario and Quebec. Under constant environmental conditions, we incubated subsamples of the surface Sphagnum mosses by using both, acetylene reduction assays (ARA) and 15N2 enriched method to measure N2 fixation rates. Same subsamples were later analyzed for N and P concentrations. Our preliminary data show that the increase of P concentration within moss capitula is related to a significant linear increase of ARA rates (R2=0.18, p<0.0001, N=150). N:P ratios showed a significant negative linear relationship with ARA (R2=0.34, p<0.0001, N=150) indicating that P limitation in the photosynthetically active part of mosses in bogs may also indicate P limitation on microbial N2 fixation

  9. A new non-endoscopic intraoral approach for open reduction and internal fixation of subcondylar fractures of the mandible.

    PubMed

    Hakim, Samer George; Trankle, Thomas; Kimmerle, Harald; Sieg, Peter; Jacobsen, Hans-Christian

    2014-10-01

    Open reduction and internal fixation (ORIF) of subcondylar fractures of the mandible is a widely accepted treatment concept aimed at reconstruction of the vertical height of the mandibular ramus and restoration of occlusion. Here, we describe new instruments designed for ORIF via an intraoral approach using a single inverted y-miniplate. The special design allows sufficient visualisation of the fracture site and enables the establishment of a standardised procedure for the treatment of both dislocated and non-dislocated fractures. Several manoeuvres are described and some clinical cases are presented. Challenges frequently met during ORIF of subcondylar fractures via the intraoral approach such as limited exposure and visual control of fracture site can be overcome using the instruments-kit presented, which help to optimise this treatment. PMID:24613104

  10. The role of reduction and internal fixation of Lisfranc fracture–dislocations: a systematic review of the literature

    PubMed Central

    Stavlas, Panagiotis; Roberts, Craig S.; Xypnitos, Fragiskos N.

    2010-01-01

    A systematic review of the literature was performed in order to evaluate the role of reduction and internal fixation in the management of Lisfranc joint fracture–dislocations. Articles were extracted from the Pubmed database and the retrieved reports were included in the study only if pre-specified eligibility criteria were fulfilled. Eleven articles were eligible for the final analysis, reporting data for the management of 257 patients. Injuries of the first three metatarsal rays were treated by closed reduction and internal fixation with screws in 16.3% of the patients, open reduction and internal fixation with screws in 66.5% and open reduction and internal fixation with Kirschner wires (K-wires) in 17.1% of the patients. The preferred method for the stabilisation of the fourth and fifth metatarsal rays was K-wires. Screw-related complications were common and were reported in 16.1% of the cases. The mean American Orthopaedic Foot and Ankle Society midfoot score was 78.1 points. Post-traumatic radiographic arthritis was reported in 49.6% of the patients, but only in 7.8% of them it was severe enough to warrant an arthrodesis. We conclude that open reduction and internal fixation of the first three metatarsal rays with screws is a reliable method for the management of Lisfranc injuries. This can be complemented by K-wires application in the fourth and fifth metatarsal rays if needed. PMID:20683593

  11. A Comparison of Internal Fixation and Bipolar Hemiarthroplasty for the Treatment of Reverse Oblique Intertrochanteric Femoral Fractures in Elderly Patients

    PubMed Central

    Park, Bong-Ju; Min, Woong-Bae

    2015-01-01

    Purpose To compare the clinical and radiological results between internal fixation using the proximal femoral nail system and bipolar hemiarthroplasty (BHA) in reverse oblique intertrochanteric hip fractures in elderly patients. Materials and Methods From January 2005 to July 2012, we reviewed the medical records of 53 patients who had been treated surgically for reverse oblique intertrochanteric fracture and had been followed-up on for a minimum of two years. All patients were ≥70 years of age, and divided into two groups for retrospective evaluation. One group was treated with internal fixation using the proximal femoral nail system (31 cases), and the other group was treated with BHA (22 cases). Results Early ambulation postoperatively and less pain at postoperative three month were significantly superior in the BHA group. However, by 24 months postoperatively, the internal fixation group exhibited higher Harris scores and correspondingly less pain than the BHA group. There were no significant differences in union rate, duration of hospitalization or lateral wall fracture healing between the two groups. Four patients in the internal fixation group underwent reoperation. Conclusion In the treatment of intertrochanteric fracture of the reverse oblique type, open reduction and internal fixation should be considered to be the better choice for patients with good health and bone quality. However, in cases of severe comminition of fracture and poor bone quality, BHA is an alternative offering advantages including early ambulation, less pain at early stages, and a lower risk of reoperation.

  12. Assessment of sagittal split ramus osteotomy rigid internal fixation techniques using a finite element method.

    PubMed

    Albougha, S; Darwich, K; Darwich, M A; Albogha, M H

    2015-07-01

    In this study, finite element analysis (FEA) was used to evaluate nine rigid internal fixation techniques for sagittal split ramus osteotomy. To achieve this, a computed tomography (CT) scan of a healthy patient was obtained and used to generate the geometry of a half-mandible. The geometries of bicortical screws, miniplates, and monocortical screws were designed and combined with the mandible in nine models simulating various techniques. Four models used bicortical screws in various arrangements and four used miniplates of various designs. One model represented a hybrid technique. A load of 500 N was applied to the posterior teeth and FEA was applied. The most stable techniques were the hybrid technique and a single straight miniplate, presenting the least displacement among all models. Bicortical screws, while presenting reasonable stability, showed high strain areas near the anterior ramus ridge, superoposterior to the screws, implying a risk of bone fracture in this area. On the other hand, the T-shaped and double Y-shaped miniplates were associated with high von Mises stresses that would impair their rigidity, especially where angles appeared in their designs. We recommend the use of a single straight miniplate because it provides sufficient stable fixation with minimal risks or disadvantages. PMID:25766461

  13. Finite element analysis of three patterns of internal fixation of fractures of the mandibular condyle.

    PubMed

    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. PMID:22981343

  14. Treatment of Humeral Shaft Fractures: Minimally Invasive Plate Osteosynthesis Versus Open Reduction and Internal Fixation

    PubMed Central

    Esmailiejah, Ali Akbar; Abbasian, Mohammad Reza; Safdari, Farshad; Ashoori, Keyqobad

    2015-01-01

    Background: The optimal technique for operative fixation of humeral shaft fractures remains controversial and warrants research. Objectives: The purpose of the current study was to compare the functional and clinical outcomes of conventional open reduction and internal fixation (ORIF) with minimally invasive plate osteosynthesis (MIPO) in patients with fractures in two-third distal humeral shaft. Patients and Methods: In the current prospective case-control study, 65 patients with humeral shaft fractures were treated using ORIF (33 patients) or MIPO (32 patients). Time of surgery, time of union, incidence of varus deformity and complications were compared between the two groups. Also, the university of California-Los Angeles (UCLA) shoulder rating scale and Mayo Elbow performance score (MEPS) were used to compare the functional outcomes between the two groups. Results: The median of union time was shorter in the MIPO group (4 months versus 5 months). The time of surgery and functional outcomes based on the UCLA and MEPS scores were the same. The incidence of varus deformity was more than 5° and was higher and the incidence of nonunion, infection and iatrogenic radial nerve injury were lower in the MIPO group; however, the differences were not significant. Conclusions: Due to the shorter union time, to some extent less complication rate and comparable functional and clinical results, the authors recommend to use the MIPO technique in treating the mid-distal humeral shaft fracture. PMID:26543844

  15. Hemiarthroplasty or internal fixation for intracapsular displaced femoral neck fractures: randomised controlled trial

    PubMed Central

    2007-01-01

    Objective To compare the functional results after displaced fractures of the femoral neck treated with internal fixation or hemiarthroplasty. Design Randomised trial with blinding of assessments of functional results. Setting University hospital. Participants 222 patients; 165 (74%) women, mean age 83 years. Inclusion criteria were age above 60, ability to walk before the fracture, and no major hip pathology, regardless of cognitive function. Interventions Closed reduction and two parallel screws (112 patients) and bipolar cemented hemiarthroplasty (110 patients). Follow-up at 4, 12, and 24 months. Main outcome measures Hip function (Harris hip score), health related quality of life (Eq-5d), activities of daily living (Barthel index). In all cases high scores indicate better function. Results Mean Harris hip score in the hemiarthroplasty group was 8.2 points higher (95% confidence interval 2.8 to 13.5 points, P=0.003) at four months and 6.7 points (1.5 to 11.9 points, P=0.01) higher at 12 months. Mean Eq-5d index score at 24 months was 0.13 higher in the hemiarthroplasty group (0.01 to 0.25, P=0.03). The Eq-5d visual analogue scale was 8.7 points higher in the hemiarthroplasty group after 4 months (1.9 to 15.6, P=0.01). After 12 and 24 months the percentage scoring 95 or 100 on the Barthel index was higher in the hemiarthroplasty group (relative risk 0.67, 0.47 to 0.95, P=0.02. and 0.63, 0.42 to 0.94, P=0.02, respectively). Complications occurred in 56 (50%) patients in the internal fixation group and 16 (15%) in the hemiarthroplasty group (3.44, 2.11 to 5.60, P<0.001). In each group 39 patients (35%) died within 24 months (0.98, 0.69 to 1.40, P=0.92) Conclusions Hemiarthroplasty is associated with better functional outcome than internal fixation in treatment of displaced fractures of the femoral neck in elderly patients. Trial registration NCT00464230. PMID:18056740

  16. Light-Limited Growth Rate Modulates Nitrate Inhibition of Dinitrogen Fixation in the Marine Unicellular Cyanobacterium Crocosphaera watsonii

    PubMed Central

    Garcia, Nathan S.; Hutchins, David A.

    2014-01-01

    Biological N2 fixation is the dominant supply of new nitrogen (N) to the oceans, but is often inhibited in the presence of fixed N sources such as nitrate (NO3−). Anthropogenic fixed N inputs to the ocean are increasing, but their effect on marine N2 fixation is uncertain. Thus, global estimates of new oceanic N depend on a fundamental understanding of factors that modulate N source preferences by N2-fixing cyanobacteria. We examined the unicellular diazotroph Crocosphaera watsonii (strain WH0003) to determine how the light-limited growth rate influences the inhibitory effects of fixed N on N2 fixation. When growth (µ) was limited by low light (µ = 0.23 d−1), short-term experiments indicated that 0.4 µM NH4+ reduced N2-fixation by ∼90% relative to controls without added NH4+. In fast-growing, high-light-acclimated cultures (µ = 0.68 d−1), 2.0 µM NH4+ was needed to achieve the same effect. In long-term exposures to NO3−, inhibition of N2 fixation also varied with growth rate. In high-light-acclimated, fast-growing cultures, NO3− did not inhibit N2-fixation rates in comparison with cultures growing on N2 alone. Instead NO3− supported even faster growth, indicating that the cellular assimilation rate of N2 alone (i.e. dinitrogen reduction) could not support the light-specific maximum growth rate of Crocosphaera. When growth was severely light-limited, NO3− did not support faster growth rates but instead inhibited N2-fixation rates by 55% relative to controls. These data rest on the basic tenet that light energy is the driver of photoautotrophic growth while various nutrient substrates serve as supports. Our findings provide a novel conceptual framework to examine interactions between N source preferences and predict degrees of inhibition of N2 fixation by fixed N sources based on the growth rate as controlled by light. PMID:25503244

  17. Fractures of the radial head treated by internal fixation: late results in 26 cases.

    PubMed

    Esser, R D; Davis, S; Taavao, T

    1995-01-01

    Twenty-six patients, ranging in age from 14 to 57 years (average 29 years), were evaluated an average of 7 years and 4 months (range 1-14 years) after open reduction and internal fixation of a displaced radial head fracture. Using Mason's classification, there were 11 type II fractures, 9 type III fractures, and 6 type IV fractures with associated dislocation of the elbow. Seven patients had ipsilateral extremity injuries that included fractures of the coronoid process, capitellum, humerus, and distal radius. Using the Broberg and Morrey elbow score, good or excellent results were achieved in all Mason type II and type III fractures. Four of the six Mason type IV fractures were rated good or excellent. Fair results were obtained in two patients who had an associated dislocation of the elbow and multiple ipsilateral extremity injuries. In these two patients, secondary excision of the radial head relieved pain and yielded some improvement in flexion and forearm rotation. PMID:7562154

  18. Use of the trochanteric flip osteotomy to facilitate internal fixation of a femoral head fracture.

    PubMed

    Gillespie, James A; Marsh, Andrew G; Patil, Sanjeev R

    2016-01-01

    We report the case of a 42-year-old male who suffered a fracture-dislocation of the femoral head. After a closed reduction of the hip, this proceeded to an open reduction with internal fixation of the fractured femoral head, in addition to labral repair and micro-fracture of an articular cartilage defect. After considering the risks to the femoral head blood supply, the trochanteric flip osteotomy was used. This provided ample and safe exposure. At 14 months follow-up, the patient-reported outcome measures are favourable: modified Harris Hip Score (81/100), the non-arthritic hip score (92.5/100) and SF-12 (41/48). PMID:27470013

  19. Use of the trochanteric flip osteotomy to facilitate internal fixation of a femoral head fracture

    PubMed Central

    Gillespie, James A.; Marsh, Andrew G.; Patil, Sanjeev R.

    2016-01-01

    We report the case of a 42-year-old male who suffered a fracture–dislocation of the femoral head. After a closed reduction of the hip, this proceeded to an open reduction with internal fixation of the fractured femoral head, in addition to labral repair and micro-fracture of an articular cartilage defect. After considering the risks to the femoral head blood supply, the trochanteric flip osteotomy was used. This provided ample and safe exposure. At 14 months follow-up, the patient-reported outcome measures are favourable: modified Harris Hip Score (81/100), the non-arthritic hip score (92.5/100) and SF-12 (41/48). PMID:27470013

  20. Internal Versus External Fixation for the Treatment of Distal Radial Fractures

    PubMed Central

    Zhang, Qingyu; Liu, Fanxiao; Xiao, Zhenyun; Li, Zhenfeng; Wang, Bomin; Dong, Jinlei; Han, Yong; Zhou, Dongsheng; Li, Jianmin

    2016-01-01

    Abstract Although a serious of meta-analyses have been published to compare the effects of internal versus external fixation (IF vs EF) for treating distal radial fractures (DRF), no consensus was obtained. By performing a systematic review of overlapping meta-analyses comparing IF versus EF for the treatment of distal radial fractures, we attempted to evaluate the methodology and reporting quality of these meta-analyses, interpret the source of discordant results, and therefore determine the dominant strategy for the treatment of distal radial fractures based on the best evidence currently. An electronic databases search was conducted in MEDLINE, Embase, and Cochrane library to retrieve meta-analyses comparing IF versus EF for treating DRF. Reference lists of relevant literatures were also screened manually to retrieve additional ones. Two investigators independently assessed the eligibility of retrieved articles using predefined inclusion and exclusion criteria. All characteristics as well as outcome variables including functional outcomes, range of motion, radiological results, and complication rates with relevant heterogeneity information presented in each included study were extracted. Heterogeneity was thought to be significant when I2 > 50%. We adopted the Oxford Levels of Evidence and the Assessment of Multiple Systematic Reviews (AMSTAR) Instrument to assess the methodological quality of every included study, and applied the Jadad decision algorithm to select studies with more likely reliable conclusions. A total of 8 studies met the inclusion criteria. The AMSTAR scores ranged from 5 to 9 with a median of 7.75. Following the Jadad algorithm, the meta-analyses with most reliable results can be selected based on the search strategies and application of selection. Finally, 2 meta-analyses with most RCTs and highest AMSTAR scores were selected in this systematic review of overlapping meta-analysis. The best available evidence suggested that compared with

  1. Retromandibular approach in the management of condylar fractures by open reduction and internal fixation a prospective study

    PubMed Central

    Kshirsagar, Rajesh; Singh, Vikram; Pawar, Sudhir; Shah, Rahul

    2015-01-01

    Aim: To evaluate the efficacy and safety of the retromandibular approach in the management of condylar fractures by open reduction and internal fixation (ORIF). Materials and Methods: A total of 20 patients with unilateral mandibular condylar fractures underwent ORIF using retromandibular approach. Pertinent data were collected and subjected to evaluation. Results: The retromandibular approach was found to be expeditious in adequately exposing the fracture site and enabling ORIF. The anatomic reduction of the fractured segments and the fixation was satisfactory in all the cases. Average duration of surgery was 39 min (range: 17-56 min) for satisfactory exposure, reduction, and fixation of each condylar fracture. Conclusion: The retromandibular approach provides adequate exposure of the subcondylar region and should be considered as commendable alternative in the management of condylar fractures. PMID:27390493

  2. RuBP limitation of photosynthetic carbon fixation during NH sub 3 assimilation: Interactions between photosynthesis, respiration, and ammonium assimilation in N-limited green algae

    SciTech Connect

    Elrifi, I.R.; Holmes, J.J.; Weger, H.G.; Mayo, W.P.; Turpin, D.H. )

    1988-06-01

    The effects of ammonium assimilation on photosynthetic carbon fixation and O{sub 2} exchange were examined in two species of N-limited green algae, Chlorella pyrenoidosa and Selenastrum minutum. Under light-saturating conditions, ammonium assimilation resulted in a suppression of photosynthetic carbon fixation by S. minutum but not by C. pyrenoidosa. These different responses are due to different relationships between cellular ribulose bisphosphate (RuBP) concentration and the RuBP binding site density of ribulose bisphosphate carboxylase/oxygenase (Rubisco). In both species, ammonium assimilation resulted in a decrease in RuBP concentration. In S. minutum the concentration fell below the RuBP binding site density of Rubisco, indicating RuBP limitation of carboxylation. In contrast, RuBP concentration remained above the binding site density in C. pyrenoidosa. Compromising RuBP regeneration in C. pyrenoidosa with low light resulted in an ammonium-induced decrease in RuBP concentration below the RuBP binding site density of Rubisco. This resulted in a decrease in photosynthetic carbon fixation. In both species, ammonium assimilation resulted in a larger decrease in net O{sub 2} evolution than in carbon fixation. Mass spectrometric analysis shows this to be a result of an increase in the rate of mitochondrial respiration in the light.

  3. Percutaneous Reduction and Fixation with Kirschner Wires versus Open Reduction Internal Fixation for the Management of Calcaneal Fractures: A Meta-Analysis

    PubMed Central

    Wu, Jianbin; Zhou, Feiya; Yang, Lei; Tan, Jun

    2016-01-01

    The aim of our meta-analysis was to compare outcomes for two surgical treatments of calcaneal fractures, percutaneous reduction and fixation with Kirschner wires (PRFK) and open reduction internal fixation (ORIF), with the intent of evaluating the quality of evidence to inform practice. Search of MEDLINE, Cochrane and CNKI databases to identify randomized controlled trials (RCTs) comparing PRKF and ORIF on the following outcomes: post-operative function, complications and quality of the reduction. Odd ratios (OR) and weighted mean differences were pooled using either a fixed-effects or random-effects model, depending on the heterogeneity of the trials included in the analysis. Eighteen RCTs provided the data from 1407 patients. PRFK was associated with a lower risk of surgical wound complications, and ORIF with better post-operative function, angle of Gissane, calcaneal height, and calcaneal width. There were no statistically significant differences between the techniques with regards to post-operative Böhler’s angle. PRFK does not provide a substantive advantage over ORIF for the treatment of calcaneal fractures in adults. PRFK may, however, yield comparable functional outcomes to ORIF for closed Sanders type II calcaneal fractures but with less complication related to surgical wound healing. PMID:27457262

  4. Proximal tibial fractures with impending compartment syndrome managed by fasciotomy and internal fixation: A retrospective analysis of 15 cases

    PubMed Central

    Sharma, Naveen; Singh, Varun; Agrawal, Ashish; Bhargava, Rakesh

    2015-01-01

    Background: Proximal tibia fractures with compartment syndrome present a challenge for orthopedic surgeons. More often than not these patients are subjected to multiple surgeries and are complicated by infection osteomyelitis and poor rehabilitation. There is no consensus in the management of these fractures. Most common mode is to do early fasciotomy with external fixation, followed by second stage definitive fixation. We performed a retrospective study of proximal tibia fractures with impending compartment syndrome treated by single stage fasciotomy and internal fixation. Results in terms of early fracture union, minimum complications and early patient mobilization were very good. Materials and Methods: Fifteen patients who were operated between July 2011 and June 2012 were selected for the study. All documents from their admission until the last followup in December 2013 were reviewed, data regarding complications collected and results were evaluated using Oxford Knee scoring system. Results: At the final outcome, there was anatomical or near anatomical alignment with no postoperative problems with range of motion of near complete flexion (>120) in all patients within 3 months. 13 patients started full weight bearing walking at 3 months. Delayed union in two patients and skin necrosis in one patient was observed. Conclusions: Since the results are encouraging and the rehabilitation time is much less when compared to conventional approaches, it is recommended using this protocol to perform early fasciotomy with the definitive internal fixation as single stage surgery to obtain excellent followup results and to reduce rehabilitation time, secondary trauma, expense of treatment and infection rate. PMID:26538755

  5. Internal Fixation Versus Nonoperative Treatment for Displaced 3-Part or 4-Part Proximal Humeral Fractures in Elderly Patients: A Meta-Analysis of Randomized Controlled Trials

    PubMed Central

    Li, Jing; Chen, Aimin

    2013-01-01

    Background A few studies focused on open reduction and internal fixation (ORIF) or nonoperative treatment of displaced 3-part or 4-part proximal humeral fractures in elderly patients have been published, all of whom had a low number of patients. In this meta-analysis of randomized controlled trials (RCTs), we aimed to assess the effect of ORIF or nonoperative treatment of displaced 3-part or 4-part proximal humeral fractures in elderly patients on the clinical outcomes and re-evaluate of the potential benefits of conservative treatment. Methods We searched PubMed and the Cochrane Central Register of Controlled Trials databases for randomized controlled trials comparing ORIF and nonoperative treatment of displaced 3-part or 4-part proximal humeral fractures in elderly patients. Our outcome measures were the Constant scores. Results: Three randomized controlled trials with a total of 130 patients were identified and analyzed. The overall results based on fixed-effect model did not support the treatment of open reduction and internal fixation to improve the functional outcome when compared with nonoperative treatment for treating elderly patients with displaced 3-part or 4-part proximal humeral fractures (WMD −0.51, 95% CI: −7.25 to 6.22, P = 0.88, I2 = 0%). Conclusions Although our meta-analysis did not support the treatment of open reduction and internal fixation to improve the functional outcome when compared with nonoperative treatment for treating elderly patients with displaced 3-part or 4-part proximal humeral fractures, this result must be considered in the context of variable patient demographics. Only a limited recommendation can be made based on current data. Considering the limitations of included studies, a large, well designed trial that incorporates the evaluation of clinically relevant outcomes in participants with different underlying risks of shoulder function is required to more adequately assess the role for ORIF or nonoperative

  6. Bio-Environment-Induced Degradation and Failure of Internal Fixation Implants.

    PubMed

    Zhou, Yan; Perkins, Luke A; Wang, Guodong; Zhou, Dongsheng; Liang, Hong

    2015-01-01

    Internal fixations provide fast healing but their failure remains problematic to patients. Here, we report an experimental study in failure of three typical cases of metals: a bent intramedullary stainless steel nail, a broken exterior pure Ti plate, and a broken intramedullary stainless steel nail. Characterization of the bent nail indicates that those metals are vulnerable to corrosion with the evidence of increased surface roughness and embrittlement. Depredated surface of the Ti plate resulted debris particles in the surrounding tissue of 15.2 ± 6.5 μm in size. Nanoparticles were observed in transmission electron microscope. The electron diffraction pattern of the debris indicates a combination of nanocrystalline and amorphous phases. The failure mode of the broken nail made of stainless steel was found to be fatigue initiated from the surface. This study clearly shows the biological-attack induced surface degradation resulting in debris and fatigue. Future design and selection of implant materials should consider such factors for improvement. PMID:26501330

  7. Bio-Environment-Induced Degradation and Failure of Internal Fixation Implants

    PubMed Central

    Zhou, Yan; Perkins, Luke A.; Wang, Guodong; Zhou, Dongsheng; Liang, Hong

    2015-01-01

    Internal fixations provide fast healing but their failure remains problematic to patients. Here, we report an experimental study in failure of three typical cases of metals: a bent intramedullary stainless steel nail, a broken exterior pure Ti plate, and a broken intramedullary stainless steel nail. Characterization of the bent nail indicates that those metals are vulnerable to corrosion with the evidence of increased surface roughness and embrittlement. Depredated surface of the Ti plate resulted debris particles in the surrounding tissue of 15.2 ± 6.5 μm in size. Nanoparticles were observed in transmission electron microscope. The electron diffraction pattern of the debris indicates a combination of nanocrystalline and amorphous phases. The failure mode of the broken nail made of stainless steel was found to be fatigue initiated from the surface. This study clearly shows the biological-attack induced surface degradation resulting in debris and fatigue. Future design and selection of implant materials should consider such factors for improvement. PMID:26501330

  8. The mechanical and morphological properties of bone beneath internal fixation plates of differing rigidity.

    PubMed

    Claes, L

    1989-01-01

    The internal fixation of diaphyseal fractures by bone plates is a well recognized treatment. The normal physiological stress of bone is reduced by plates that cause a negative balance of bone-remodeling processes. Many investigators have shown that the degree of stress protection is dependent on the rigidity of the plates. It was the aim of this study to quantify mechanical and morphological changes at different locations in a plated diaphyseal bone as a function of differing plate rigidity. Two types of plates with the same size but different materials were used. The stainless steel plates had a modulus of elasticity and bending stiffness 3.2 times higher than the carbon fiber reinforced carbon plates. Both types of plates were applied to the intact right and left femora of six foxhounds for 6 months. The stiffer stainless steel plates led to a significantly higher bone loss and correspondingly greater loss of mechanical properties. These effects were greatest directly beneath the plate and less with increasing distance from the plate. PMID:2918416

  9. Bioabsorbable fish scale for the internal fixation of fracture: a preliminary study.

    PubMed

    Chou, Cheng-Hung; Chen, Yong-Guei; Lin, Chien-Chen; Lin, Shang-Ming; Yang, Kai-Chiang; Chang, Shih-Hsin

    2014-09-01

    Fish scales, which consist of type I collagen and hydroxyapatite (HA), were used to fabricate a bioabsorbable bone pin in this study. Fresh fish scales were decellularized and characterized to provide higher biocompatibility. The mechanical properties of fish scales were tested, and the microstructure of an acellular fish scale was examined. The growth curve of a myoblastic cell line (C2C12), which was cultured on the acellular fish scales, implied biocompatibility in vitro, and the morphology of the cells cultured on the scales was observed using scanning electron microscopy (SEM). A bone pin made of decellularized fish scales was used for the internal fixation of femur fractures in New Zealand rabbits. Periodic X-ray evaluations were obtained, and histologic examinations were performed postoperatively. The present results show good cell growth on decellularized fish scales, implying great biocompatibility in vitro. Using SEM, the cell morphology revealed great adhesion on a native, layered collagen structure. The Young's modulus was 332 ± 50.4 MPa and the tensile strength was 34.4 ± 6.9 MPa for the decellularized fish scales. Animal studies revealed that a fish-scale-derived bone pin improved the healing of bone fractures and degraded with time. After an 8-week implantation, the bone pin integrated with the adjacent tissue, and new extracellular matrix was synthesized around the implant. Our results proved that fish-scale-derived bone pins are a promising implant material for bone healing and clinical applications. PMID:25211643

  10. Clinical outcome of arthrodesis of the ankle using rigid internal fixation with cancellous screws.

    PubMed

    Monroe, M T; Beals, T C; Manoli, A

    1999-04-01

    Thirty consecutive patients underwent arthrodesis of the ankle using rigid internal fixation with cancellous screws between 1992 and 1996. One patient died of causes unrelated to the surgery before bony union. Primary fusion occurred in 27 of the remaining 29 patients (93%). The average time to primary union was 9 weeks. Two patients developed a delayed union and were treated with an additional bone-grafting procedure. Ultimately, each of the 29 patients went on to fusion. Use of tobacco during the postoperative period had no apparent effect on the rate of fusion or time to fusion. Twenty-five patients were available for clinical evaluation at an average of 24 months after surgery. Subjective evaluation using questionnaires revealed a high level of satisfaction. All patients stated that they would undergo the procedure again. The mean postoperative score on the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale was 81 points, compared with 48 points preoperatively (of a possible 100). Constant pain was the reason given by all patients for seeking treatment. After the arthrodesis, pain was reported as absent in 13 and occasional in 12 patients. All patients noted less pain in the hindfoot after fusion of the ankle. Active litigation and Workers' Compensation claims during the perioperative period had a significant negative effect on scores on the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale and seemed to decrease patients' perceived ability to return to work. PMID:10229278

  11. The Relationship of the Facial Nerve to the Condylar Process: A Cadaveric Study with Implications for Open Reduction Internal Fixation

    PubMed Central

    Barham, H. P.; Collister, P.; Eusterman, V. D.; Terella, A. M.

    2015-01-01

    Introduction. The mandibular condyle is the most common site of mandibular fracture. Surgical treatment of condylar fractures by open reduction and internal fixation (ORIF) demands direct visualization of the fracture. This project aimed to investigate the anatomic relationship of the tragus to the facial nerve and condylar process. Materials and Methods. Twelve fresh hemicadavers heads were used. An extended retromandibular/preauricular approach was utilized, with the incision being based parallel to the posterior edge of the ramus. Measurements were obtained from the tragus to the facial nerve and condylar process. Results. The temporozygomatic division of the facial nerve was encountered during each approach, crossing the mandible at the condylar neck. The mean tissue depth separating the facial nerve from the condylar neck was 5.5 mm (range: 3.5 mm–7 mm, SD 1.2 mm). The upper division of the facial nerve crossed the posterior border of the condylar process on average 2.31 cm (SD 0.10 cm) anterior to the tragus. Conclusions. This study suggests that the temporozygomatic division of the facial nerve will be encountered in most approaches to the condylar process. As visualization of the relationship of the facial nerve to condyle is often limited, recognition that, on average, 5.5 mm of tissue separates condylar process from nerve should help reduce the incidence of facial nerve injury during this procedure. PMID:26421016

  12. Mechanical analysis of a rodent segmental bone defect model: the effects of internal fixation and implant stiffness on load transfer.

    PubMed

    Yavari, S Amin; van der Stok, J; Ahmadi, S M; Wauthle, R; Schrooten, J; Weinans, H; Zadpoor, A A

    2014-08-22

    Segmental bone defect animal models are often used for evaluating the bone regeneration performance of bone substituting biomaterials. Since bone regeneration is dependent on mechanical loading, it is important to determine mechanical load transfer after stabilization of the defect and to study the effects of biomaterial stiffness on the transmitted load. In this study, we assess the mechanical load transmitted over a 6mm femur defect that is stabilized with an internal PEEK fixation plate. Subsequently, three types of selective laser melted porous titanium implants with different stiffness values were used to graft the defect (five specimens per group). In one additional group, the defect was left empty. Micro strain gauges were used to measure strain values at four different locations of the fixation plate during external loading on the femoral head. The load sharing between the fixation plate and titanium implant was highly variable with standard deviations of measured strain values between 31 and 93% of the mean values. As a consequence, no significant differences were measured between the forces transmitted through the titanium implants with different elastic moduli. Only some non-significant trends were observed in the mean strain values that, consistent with the results of a previous finite element study, implied the force transmitted through the implant increases with the implant stiffness. The applied internal fixation method does not standardize mechanical loading over the defect to enable detecting small differences in bone regeneration performances of bone substituting biomaterials. In conclusion, the fixation method requires further optimization to reduce the effects of the operative procedure and make the mechanical loading more consistent and improve the overall sensitivity of this rat femur defect model. PMID:24882739

  13. Treatment of stress fracture of the olecranon in throwing athletes with internal fixation through a small incision

    PubMed Central

    2012-01-01

    The present study is a report of retrospective case series of stress fracture of the olecranon. Six patients presented posterior elbow pain in throwing in baseball and softball, but fracture was not diagnosed in radiographs. We detected stress fracture of the olecranon using computed tomographic (CT) scan and treated the patient with internal fixation with a headless cannulated double threaded screw through a small skin incision. All patients returned to competitive level without elbow complaints after the operation. When throwing athletes present with unusual posterior elbow pain and no significant findings on radiographs, a CT scan examination should be performed. We recommend surgical treatment of internal fixation with a screw through a small skin incision, as a good option for stress fracture of the olecranon in order to allow early return to sports activity in competitive athletes. PMID:23241173

  14. Evaluation of trapezoidal-shaped 3-D plates for internal fixation of mandibular subcondylar fractures in adults

    PubMed Central

    Chaudhary, Manoj; Pant, Harshvardhan; Singh, Manpreet; Vashistha, Arpit; Kaur, Gagandeep

    2015-01-01

    Aims The purpose of this study is to evaluate the clinical results and to assess the efficacy, stability, and rigidity of trapezoidal 3-D plates for osteosynthesis in adult mandibular subcondylar fracture patients. Methods This study included 15 cases of trauma having mandibular subcondylar fractures, in which open reduction and internal fixation are indicated. After selecting patient according to the inclusion criteria, all patients underwent open reduction and rigid fixation. Fracture was then stabilized using 4 hole, 2.0 mm trapezoidal-shaped 3-D titanium plates using retromandibular incision. Postoperative clinical examination was carried out on 3rd day; 1st, 2nd, and 4th weeks; and 3rd and 6th months. Results The results of this study suggest that the fixation of mandibular subcondylar fracture with trapezoidal-shaped 3-D plates provides three-dimensional stability and carries low morbidity. Conclusion Patients with gross displacement of condylar fragment, major reduction in posterior facial height, and deranged occlusion can be successfully managed by open reduction of condylar fracture and its fixation using 3-D plates. PMID:26587378

  15. Fibular Strut Graft Augmentation for Open Reduction and Internal Fixation of Proximal Humerus Fractures

    PubMed Central

    Saltzman, Bryan M.; Erickson, Brandon J.; Harris, Joshua D.; Gupta, Anil K.; Mighell, Mark; Romeo, Anthony A.

    2016-01-01

    Background: Proximal humerus fractures are common problems plaguing the elderly population. Purpose: The purposes of this study were to determine the outcomes of fibular strut allografts in treatment of proximal humerus fractures with open reduction internal fixation (ORIF) and to present the authors’ preferred surgical technique. The hypothesis was that the use of fibular strut allografts in treating proximal humerus fractures with ORIF will provide low reoperation rates with acceptable outcomes. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review was registered with PROSPERO and performed with PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines using 3 publicly available free databases. Therapeutic clinical outcome investigations reporting arthroscopic elbow outcomes with levels of evidence 1 through 4 were eligible for inclusion. All study, subject, and surgical technique demographics were analyzed and compared between continents and countries. Statistics were calculated using Student t tests, 1-way analysis of variance, chi-square tests, and 2-proportion Z tests. Results: Four studies met the inclusion criteria. While there is great heterogeneity existing in the literature surrounding use of a fibular strut allograft as an adjunct to ORIF of proximal humerus fractures, current evidence shows a humeral head screw penetration rate of 3.7% with acceptable functional outcome scores, with a reoperation rate of 4.4% at a weighted mean 80.78 weeks (1.55 years) of postoperative follow-up. Conclusion: There is great heterogeneity that exists in the literature surrounding the use of a fibular strut allograft as an adjunct to ORIF of proximal humerus fractures. Current evidence shows a screw penetration rate of 3.7% with acceptable functional outcome scores, demonstrating fibular strut allograft is a viable option for treating proximal humerus fractures. PMID:27504463

  16. Variation of plate fixation for mandibular advancement with intraoral vertical ramus osteotomy using endoscopically assisted intraoral rigid or semi-rigid internal fixation: Case series study: Postoperative condylar seating control for mandibular advancement.

    PubMed

    Hara, Shingo; Mitsugi, Masaharu; Tatemoto, Yukihiro

    2015-12-01

    The purpose of the present study was to evaluate the safety and efficacy associated with mandibular advancement by intraoral vertical ramus osteotomy (IVRO) with endoscopically assisted intraoral rigid or semi-rigid internal fixation. The study sample included all patients who had undergone an mandibular advancement by IVRO procedure with endoscopically assisted intraoral plate fixation from September 2008 to May 2012. An mandibular advancement by IVRO with endoscopically assisted intraoral rigid or semi-rigid internal fixation was used for mandibular advancement. The patients were analyzed prospectively, with more than 2 years of follow-up, and were evaluated in terms of functional results, postoperative complications, and skeletal stability. A total of 14 patients (bilateral, 7 patients with class II; unilateral, 7 patients with asymmetry) were included in the present study. The average degree of mandibular advancement was 5.5 ± 1.9 mm (range, 3-9 mm). Both the occlusal relationship and facial appearance in all patients were significantly improved by the surgical-orthodontic treatment, with no major harmful clinical symptoms. In addition, one-screw semi-rigid fixation could control postoperative passive condylar seating. This study showed that mandibular advancement by IVRO with endoscopically assisted, intraoral semi-rigid internal fixation offers a promising treatment alternative for patients with skeletal class II malocclusion or facial asymmetry. PMID:26610634

  17. Limited photosynthetic electron flow but no CO2 fixation in Chlamydomonas mutants lacking photosystem I.

    PubMed

    Cournac, L; Redding, K; Bennoun, P; Peltier, G

    1997-10-13

    By measuring O2 and CO2 exchange in mutants of the green alga Chlamydomonas reinhardtii in which genes encoding the reaction center of photosystem I (psaA or psaB) have been deleted, we found that a photosystem II-dependent electron flow using O2 as the final acceptor can be sustained in the light. However, in contrast with recent reports using other Chlamydomonas mutants (B4 and F8), we show here that CO2 fixation does not occur in the absence of photosystem I. By deleting the psaA gene in both B4 and F8 strains, we conclude that the ability of these mutants to fix CO2 in the light is due to the presence of residual amounts of photosystem I. PMID:9369234

  18. Internal fixation of distal tibiofibular syndesmotic injuries: a systematic review with meta-analysis.

    PubMed

    Wang, Chen; Ma, Xin; Wang, Xu; Huang, Jiazhang; Zhang, Chao; Chen, Li

    2013-09-01

    No consensus had been reached about the optimal method for syndesmotic fixation. The present study analysed syndesmotic fixation based on the highest level of clinical evidence in order to obtain more reliable results. Medline, Embase and Cochrane database were searched through the OVID retrieval engine. Manual searching was undertaken afterward to identify additional studies. Only randomized controlled trials (RCT) and prospective comparative studies were selected for final inclusion. Study screening and data extraction were completed independently by two reviewers. All study characteristics were summarized into a table. The extracted data were used for data analysis. Twelve studies were finally included: six of them were RCTs, two were quasi-randomized studies and four were prospective comparative studies. Four comparisons with traditional metallic screw were identified in terms of bioabsorbable screws, tricortical fixation method, suture-button device as well as non-fixation choice in low syndesmotic injuries. Both absorbable screws and the tricortical fixation method showed almost no better results than traditional quadricortical metallic screw (p > 0.05). Additionally, existing studies could not illustrate their efficiency of reducing hardware removal rate. The suture button technique had significantly better functional score (p = 0.003), ankle motion (p = 0.02), time to full weightbearing (p < 0.0001) and much less complications (p = 0.0008) based on short and intermediate term follow-up data. Transfixation in low syndesmotic injuries showed poorer results than the non fixed group in all outcome measurements, but didn't reach a significant level (p > 0.05). The present evidence still couldn't find superior performance of the bioabsorbable screw and tricortical fixation method. Their true effects in decreasing second operation rate need further specific studies. Better results of the suture-button made it a promising technique, but it still needs long

  19. The retromandibular transparotid approach for reduction and rigid internal fixation using two locking miniplates in mandibular condylar neck fractures.

    PubMed

    Kanno, T; Sukegawa, S; Tatsumi, H; Nariai, Y; Ishibashi, H; Furuki, Y; Sekine, J

    2014-02-01

    We evaluated the safety, efficacy, and morbidity associated with the treatment of displaced mandibular condylar neck fractures using a retromandibular transparotid approach to reduce and rigidly fix using two 2.0-mm locking miniplates. Our surgical inclusion criteria were: patient selection of open reduction and fixation, displaced unilateral condylar fractures with derangement of occlusion, and bilateral condylar fractures with an anterior open bite. The study group consisted of 19 patients who underwent surgery for 19 mandibular condylar neck fractures; patients were analyzed prospectively, with more than 6 months of follow-up, and were evaluated in terms of functional results, scar formation, postoperative complications, and stability of fixation. The results showed that functional occlusion identical to the preoperative condition and correct anatomical reduction of the condylar segments in centric occlusion, followed by immediate functional recovery, was achieved in all patients. No patient suffered from any major or permanent complication postoperatively, although there were two cases (11%) of temporary facial nerve palsy, which resolved completely within 3 months. Surgical scars were barely visible. The retromandibular transparotid approach with open reduction and rigid internal fixation for displaced condylar neck fractures of the mandible is a feasible and safe, minimally invasive surgical technique that provides reliable clinical results. PMID:24070772

  20. The use of fibrin and gelatin fixation to repair a kinked internal carotid artery in carotid endarterectomy

    PubMed Central

    Kubota, Hisashi; Sanada, Yasuhiro; Tanikawa, Rokuya; Kato, Amami

    2016-01-01

    Background: The kinking of the internal carotid artery (ICA) after final closure in carotid endarterectomy (CEA) is thought to be uncommon. When it occurs, it is mandatory to reconstruct ICA to preserve normal blood flow. We herein present a case in which a fixation technique was applied to repair an ICA that became kinked during CEA. Case Description: A 68-year-old man presented with cerebral infarction due to an artery-to-artery embolism from the right cervical ICA stenosis. CEA was performed 12 days after admission. After final closure, a distal portion of ICA was found to have been kinked following plaque resection in CEA procedure. Fixation with fibrin glue and gelatin was used to reinforce the arterial wall and repair the kink. Postoperative magnetic resonance angiography demonstrated the release of the kink in ICA. Conclusion: Fixation with fibrin and gelatin is a salvage armamentarium that can be considered in CEA for the repair of kinked or tortuous ICA. PMID:27308092

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

    PubMed Central

    2012-01-01

    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. PMID:22280557

  2. Closed reduction and internal fixation for intertrochanteric femoral fractures is safer and more efficient using two fluoroscopes simultaneously.

    PubMed

    Brin, Y S; Palmanovich, E; Aliev, E; Laver, L; Yaacobi, E; Nyska, M; Kish, B J

    2014-07-01

    The purpose of the study was to assess whether using two fluoroscopes simultaneously in closed reduction and internal fixation of a stable intertrochanteric fracture reduces radiation and operation time. Patients who sustained a stable intertrochanteric femoral fracture were operated in our institution with closed reduction and internal fixation. They were randomly allocated to be operated with the assistance of one or two fluoroscopes. With one device, the radiology technician controlled and moved it to the desired anterior-posterior or axial view. With two fluoroscopes, one was positioned in the anterior-posterior view and the other in the axial view, both controlled by the surgeon. Total radiation and operation time were collected for all patients and compared between the two groups. A total of 27 patients participated in the study. One fluoroscope was used for 13 surgeries and two in 14. Total radiation time was shorter with two fluoroscopes compared to the use of one (36.6±8.6s versus 51.2±18.9s, respectively; p<0.02), as was total operation time (24.3±4.2min and 34.7±11.9min, respectively; p<0.01). Working simultaneously with two fluoroscopic devices is safer for the medical team in the operating theatre, because it decreases the patient's radiation exposure, wound exposure time, and anaesthesia time. It saves operating room time and fluoroscopy personnel during the operation. When operating on hip fractures that are planned to be reduced and fixated, we recommend working with two fluoroscopes simultaneously. PMID:24656301

  3. Parallel analysis of finite element model controlled trial and retrospective case control study on percutaneous internal fixation for vertical sacral fractures

    PubMed Central

    2013-01-01

    Background Although percutaneous posterior-ring tension-band metallic plate and percutaneous iliosacral screws are used to fix unstable posterior pelvic ring fractures, the biomechanical stability and compatibility of both internal fixation techniques for the treatment of Denis I, II and III type vertical sacral fractures remain unclear. Methods Using CT and MR images of the second generation of Chinese Digitized Human “male No. 23”, two groups of finite element models were developed for Denis I, II and III type vertical sacral fractures with ipsilateral superior and inferior pubic ramus fractures treated with either a percutaneous metallic plate or a percutaneous screw. Accordingly, two groups of clinical cases that were fixed using the above-mentioned two internal fixation techniques were retrospectively evaluated to compare postoperative effect and function. Parallel analysis was performed with a finite element model controlled trial and a case control study. Results The difference of the postoperative Majeed standards and outcome rates between two case groups was no statistically significant (P > 0.05). Accordingly, the high values of the maximum displacements/stresses of the plate-fixation model group approximated those of the screw-fixation model group. However, further simulation of Denis I, II and III type fractures in each group of models found that the biomechanics of the plate-fixation models became increasingly stable and compatible, whereas the biomechanics of the screw-fixation models maintained tiny fluctuations. When treating Denis III fractures, the biomechanical effects of the pelvic ring of the plate-fixation model were better than the screw-fixation model. Conclusions Percutaneous plate and screw fixations are both appropriate for the treatment of Denis I and II type vertical sacral fractures; whereas percutaneous plate fixation appears be superior to percutaneous screw fixation for Denis III type vertical sacral fracture. Biomechanical

  4. Hybrid Anterolateral Approach for Open Reduction and Internal Fixation of Femoral Neck Fractures.

    PubMed

    Vopat, Bryan G; Daniels, Alan H; Lareau, Craig R; Christino, Melissa A; Kane, Patrick M; Hayda, Roman A; Born, Christopher T

    2015-07-01

    Displaced femoral neck fractures in physiologically young patients are best treated with anatomic reduction and stable fixation. Several surgical approaches to the femoral neck have previously been described, although they are fraught with disadvantages such as poor visualization, the need for 2 incisions, and risk of injury to the lateral femoral cutaneous nerve and branches of the medial femoral circumflex artery. The authors' hybrid anterolateral approach to the hip allows for excellent visualization of femoral neck fractures and for placement of plate and/or screw constructs through a single incision. This surgical technique additionally minimizes risk to neurovascular structures. PMID:26186310

  5. Photoelastic stress analysis of internal fixation techniques for femur shaft crack

    NASA Astrophysics Data System (ADS)

    Liu, Tong; Chai, Gin B.; Asundi, Anand K.; Murugiah, Arumaaran

    2001-06-01

    In this paper, a photoelastic stress analysis is carried out for a cracked femur bone with compression plate fixation. A loading rig has been designed and manufactured to apply forces in the physical directions on the 2D modal of the femur bone based on a single-leg-stance. Three femur models made of photoelastic materials had been fabricated with three configurations and loaded. A recently developed three- load to phase shifting method is adopted to extract the full-field quantitative information from the fringe patterns of the loaded models. A comparison shows that the configuration where the screws point away from each other had the best effectiveness.

  6. Technical tips for (dry) arthroscopic reduction and internal fixation of distal radius fractures.

    PubMed

    Del Piñal, Francisco

    2011-10-01

    Contrary to general belief, arthroscopic assisted reduction in distal radius fractures can be done in an expeditious manner and with minimal consumption of operating room resources. This article presents the steps for a pleasant arthroscopic experience in detail. The technique proposed combines the benefits of rigid fixation with volar locking plates (for the extra-articular component) and arthroscopic control of the reduction (for the articular component). It is important that the operation be carried out using the dry arthroscopic technique. However, arthroscopy is just an addition to conventional methods. Thorough knowledge of and facility with classic techniques of distal radius fracture treatment is essential for a good result. PMID:21971058

  7. Diurnal variation in the coupling of photosynthetic electron transport and carbon fixation in iron-limited phytoplankton in the NE subarctic Pacific

    NASA Astrophysics Data System (ADS)

    Schuback, Nina; Flecken, Mirkko; Maldonado, Maria T.; Tortell, Philippe D.

    2016-02-01

    Active chlorophyll a fluorescence approaches, including fast repetition rate fluorometry (FRRF), have the potential to provide estimates of phytoplankton primary productivity at an unprecedented spatial and temporal resolution. FRRF-derived productivity rates are based on estimates of charge separation in reaction center II (ETRRCII), which must be converted into ecologically relevant units of carbon fixation. Understanding sources of variability in the coupling of ETRRCII and carbon fixation provides physiological insight into phytoplankton photosynthesis and is critical for the application of FRRF as a primary productivity measurement tool. In the present study, we simultaneously measured phytoplankton carbon fixation and ETRRCII in the iron-limited NE subarctic Pacific over the course of a diurnal cycle. We show that rates of ETRRCII are closely tied to the diurnal cycle in light availability, whereas rates of carbon fixation appear to be influenced by endogenous changes in metabolic energy allocation under iron-limited conditions. Unsynchronized diurnal oscillations of the two rates led to 3.5-fold changes in the conversion factor between ETRRCII and carbon fixation (Kc / nPSII). Consequently, diurnal variability in phytoplankton carbon fixation cannot be adequately captured with FRRF approaches if a constant conversion factor is applied. Utilizing several auxiliary photophysiological measurements, we observed that a high conversion factor is associated with conditions of excess light and correlates with the increased expression of non-photochemical quenching (NPQ) in the pigment antenna, as derived from FRRF measurements. The observed correlation between NPQ and Kc / nPSII requires further validation but has the potential to improve estimates of phytoplankton carbon fixation rates from FRRF measurements alone.

  8. Diurnal variation in the coupling of photosynthetic electron transport and carbon fixation in iron-limited phytoplankton in the NE subarctic Pacific

    NASA Astrophysics Data System (ADS)

    Schuback, N.; Flecken, M.; Maldonado, M. T.; Tortell, P. D.

    2015-10-01

    Active chlorophyll a fluorescence approaches, including fast repetition rate fluorometry (FRRF), have the potential to provide estimates of phytoplankton primary productivity at unprecedented spatial and temporal resolution. FRRF-derived productivity rates are based on estimates of charge separation at PSII (ETRRCII), which must be converted into ecologically relevant units of carbon fixation. Understanding sources of variability in the coupling of ETRRCII and carbon fixation provides physiological insight into phytoplankton photosynthesis, and is critical for the application of FRRF as a primary productivity measurement tool. In the present study, we simultaneously measured phytoplankton carbon fixation and ETRRCII in the iron-limited NE subarctic Pacific, over the course of a diurnal cycle. We show that rates of ETRRCII are closely tied to the diurnal cycle in light availability, whereas rates of carbon fixation appear to be influenced by endogenous changes in metabolic energy allocation under iron-limited conditions. Unsynchronized diurnal oscillations of the two rates led to 3.5 fold changes in the conversion factor coupling ETRRCII and carbon fixation (Φe:C / nPSII). Consequently, diurnal variability in phytoplankton carbon fixation cannot be adequately captured with FRRF approaches if a constant conversion factor is applied. Utilizing several auxiliary photophysiological measurements, we observed that a high conversion factor is associated with conditions of excess light, and correlates with the expression of non-photochemical quenching (NPQ) in the pigment antenna, as derived from FRRF measurements. The observed correlation between NPQ and the conversion factor Φe:C / nPSII has the potential to improve estimates of phytoplankton carbon fixation rates from FRRF measurements alone.

  9. Transmasseteric antero-parotid facelift approach for open reduction and internal fixation of condylar fractures

    PubMed Central

    2015-01-01

    Surgical approaches to the condylar fracture include intraoral, preauricular, submandibular, and retromandibular approaches. Each approach has its own advantages and disadvantages. When a patient needs esthetic results and an intraoral approach is not feasible, the transmasseteric antero-parotid facelift approach is considered. This approach permits direct exposure and allow the surgeon to fixate the fractured unit tangentially. Tangential fixation is critical to osteosynthesis. Disadvantages of the transmasseteric antero-parotid facelift approach include damage to the facial nerve and a longer operation time. However, after the initial learning curve, facial nerve damage can be avoided and operation time may decrease. We report three cases of subcondylar fractures that were treated with a transmasseteric antero-parotid facelift approach. Among these, two cases had trivial complications that were easily overcome. Instead of dissecting through the parotid gland parenchyma, the transmasseteric antero-parotid facelift approach uses transmasseteric dissection and reduces facial nerve damage more than the retromandibular transparotid approach. The esthetic result is superior to that of other approaches. PMID:26131433

  10. Regional alterations in long bone 85Sr clearance produced by internal fixation devices. Part II. Histomorphometry.

    PubMed

    Simmons, D J; Daum, W J; Calhoun, J H

    1988-01-01

    The effects of each of the surgical stages involved in compression plating on the development of cortical thinning and porosity were assessed in the intact midshaft, stress-shielded femoral segments of adult mongrel dogs 6 months postoperatively. The data were evaluated in terms of a postsurgical tetracycline-based measure of remodeling and terminal 85Sr clearance (SrC) values for the plated segments of bone. Drilling had no effect on any parameter. Screw application was associated with minimal cortical thinning (p less than 0.05), while plate fixation clearly promoted thinning (p less than 0.01) and porosity (p less than 0.05). The percentage of labeled osteons, a measure of remodeling activity, increased only after plate fixation (p less than 0.05), and the labeling patterns suggested that most osteons had formed during the first 4 postsurgical months. That none of these changes were correlated with the 6-month SrC values suggests that the development of plate-induced osteopenia involves disparate histomorphometric time constants, rather than lack of any association. PMID:3225712

  11. Internal emitter limits for iodine, radium and radon daughters

    SciTech Connect

    Schlenker, R.A.

    1984-08-15

    This paper identifies some of the issues which arise in the consideration of the derivation of new limits on exposure to internal emitters. Basic and secondary radiation protection limits are discussed. Terms are defined and applied to the limitation of risk from stochastic effects. Non-stochastic data for specific internal emitters (/sup 131/I and the radium isotopes) are presented. Emphasis is placed on the quantitative aspects of the limit setting problem. 65 references, 2 figures, 12 tables.

  12. Biomechanical study in polyurethane mandibles of different metal plates and internal fixation techniques, employed in mandibular angle fractures.

    PubMed

    Semeghini Guastaldi, Fernando Pozzi; Hochuli-Vieira, Eduardo; Guastaldi, Antonio Carlos

    2014-11-01

    The aim of this study was to perform a physicochemical and morphological characterization and compare the mechanical behavior of an experimental Ti-Mo alloy to the analogous metallic Ti-based fixation system, for mandibular angle fractures. Twenty-eight polyurethane mandibles were uniformly sectioned on the left angle. These were divided into 4 groups: group Eng 1P, one 2.0-mm plate and 4 screws 6 mm long; group Eng 2P, two 2.0-mm plates, the first fixed with 4 screws 6 mm long and the second with 4 screws 12 mm long. The same groups were created for the Ti-15Mo alloy. Each group was subjected to linear vertical loading at the first molar on the plated side in a mechanical testing unit. Means and standard deviations were compared with respect to statistical significance using ANOVA. The chemical composition of the Ti-15Mo alloy was close to the nominal value. The mapping of Mo and Ti showed a homogeneous distribution. SEM of the screw revealed machining debris. For the plates, only the cpTi plate undergoes a surface treatment. The metallographic analysis reveals granular microstructure, from the thermomechanical trials. A statistically significant difference was found (P < 0.05) when the comparison between both internal fixation techniques was performed. The 2P technique showed better mechanical behavior than 1P. PMID:25340696

  13. A prospective study of midfoot osteotomy combined with adjacent joint sparing internal fixation in treatment of rigid pes cavus deformity

    PubMed Central

    2014-01-01

    Background Midfoot osteotomy has been previously confirmed to be a good method to correct pes cavus. How to fix the osteotomy and which point to choose for the procedure has been a focus for most surgeons. The aim of this study was to analyse the outcomes of a series of patients who had been treated for pes cavus deformity using midfoot osteotomy combined with adjacent joint sparing internal fixation. Materials and methods Between 2008 and 2012, 17 patients with a mean age of 16.8 years (12–36 years) were tracked after treatment by midfoot osteotomy combined with adjacent joint sparing internal fixation with three cannulated screws between the Lisfranc line and Cyma line. Clinical outcomes were assessed by measuring improvements of appearance and function, American Orthopedic Foot and Ankle Society (AOFAS) scores, and radiographic changes. Results The mean follow-up time was 25.3 months (range, 10–50). The mean healing time from the osteotomy was 7.8 weeks (range, 6–12). The appearance and weight-bearing function were significantly improved in all patients. At a final follow-up, the mean AOFAS score was 75.8/100 points (range, 63–90). The mean Meary's angle, calcaneal pitch angle, tibiotalar angle, and Hibb's angle values improved from 26.3 to 5.5, 44.5 to 28.3, 133.1 to 100.8 and 66.9 to 41.1, respectively. Adjacent joints presented no obviously arthritic degeneration at the follow-up. Subjectively, 94.1% of patients were very satisfied or satisfied with minor reservations. Objective outcomes were excellent or good in 88.2% of feet. Conclusion For the treatment of rigid pes cavus deformity, extra-articular midfoot osteotomy combined with adjacent joint sparing internal fixation is effective and safe. This surgical technique is especially effective with low rates of arthritic degeneration and joint stiffness in the adjacent joints and little reduction of ankle and foot flexibility. PMID:24898481

  14. The factors affecting outcome after non-vascular bone grafting and internal fixation for nonunion of the scaphoid.

    PubMed

    Ramamurthy, C; Cutler, L; Nuttall, D; Simison, A J M; Trail, I A; Stanley, J K

    2007-05-01

    This study identified variables which influence the outcome of surgical management on 126 ununited scaphoid fractures managed by internal fixation and non-vascular bone grafting. The site of fracture was defined by a new method: the ratio of the length of the proximal fragment to the sum of the lengths of both fragments, calculated using specific views in the plain radiographs. Bone healing occurred in 71% (89) of cases. Only the site of nonunion (p = 1 x 10(-6)) and the delay to surgery (p = 0.001) remained significant on multivariate analysis. The effect of surgical delay on the probability of union increased as the fracture site moved proximally. A prediction model was produced by stepwise logistic regression analysis, enabling the surgeon to predict the success of surgery where the site of the nonunion and delay to surgery is known. PMID:17540748

  15. Open reduction-internal fixation of a navicular body fracture with dorsal displacement of the first and second cuneiforms: a case report.

    PubMed

    Andersen, Robert C; Neiderer, Katherine; Martin, Billy; Dancho, James

    2013-01-01

    Body fractures of the tarsal navicular are relatively uncommon. To date, there is little literature discussing a navicular body fracture with dorsal subluxation of the first and second cuneiforms over the navicular. This case study presents a 30-year-old patient with this injury. He underwent open reduction internal fixation of the navicular body fracture successfully but failed adequate reduction of the navicular cuneiform joint after ligamentous reconstruction. After revisional surgery, he also failed 6 weeks of percutanous pinning with Kirschner-wire fixation. When comparing the literature of a similar injury, the Lisfranc fracture disclocation, the same principles may apply. One should consider rigid open reduction internal fixation or even primary fusion to treat disclocation of the naviculocuneiform joint following a navicular body fracture. PMID:23697734

  16. An in vivo evaluation of PLLA/PLLA-gHA nano-composite for internal fixation of mandibular bone fractures.

    PubMed

    Peng, Weihai; Zheng, Wei; Shi, Kai; Wang, Wangshu; Shao, Ying; Zhang, Duo

    2015-12-01

    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. PMID:26551378

  17. Internal fixation of fractures of the shaft of the humerus by dynamic compression plate or intramedullary nail: A prospective study

    PubMed Central

    Raghavendra, S; Bhalodiya, Haresh P

    2007-01-01

    Background: The indications for surgical management of fractures of the shaft of the humerus are clear, but selecting the right implant for internal fixation of humeral fractures has been a dilemma. Materials and Methods: Thirty-six patients (mean age 40.53 years) with fractures of the shaft of the humerus were followed for 12 to 24 months in a prospective study. Eighteen patients each underwent open reduction and internal fixation with compression plating and ante grade interlock nailing. Clinical and radiographic outcome measures included fracture healing, shoulder and elbow functions, need for additional procedures and any complication such as infection and recovery of radial nerve palsy. The results were analyzed statistically using the SPSS 11.5 software, with parametric and nonparametric tests. Results: Nine of the fractures treated with compression plating and seven of those treated with interlock nailing achieved union within six months. Though there was no significant difference in union time between the treatment groups, patients operated with interlock nailing underwent more number of secondary bone grafting procedures to obtain union (six against two). There were 12 patients (66.6%) with excellent and good results in the plating group compared to four patients (25%) in the nailing group. Interlock nailing was associated with significant reduction in shoulder function (P=0.03) and in overall results (P=0.02). Conclusion: Though there was no significant difference between plating or nailing in terms of time to union, compression plating is the preferred method in the majority of fractures of the shaft of the humerus with better preservation of joint function and lesser need for secondary bone grafting for union. PMID:21139747

  18. Limits on oxygen concentration in the prebiological atmosphere and the rate of abiotic fixation of nitrogen

    NASA Astrophysics Data System (ADS)

    Kasting, J. F.; Walker, J. C. G.

    1981-02-01

    Two possible scenarios in early terrestrial atmospheric evolution are examined using a one-dimensional chemistry and flow model of the atmosphere. In each case the production of oxygen results from photolysis of H2O followed by the escape of hydrogen to space. In case 1 the rate of release of reduced volcanic gases is assumed to be greater than the oxygen production rate in leading to ground-level-oxygen concentrations on the order of 10 to the -13th PAL (present atmospheric level). In case 2, the volcanic reduced gas source is omitted, as in the case during an extended period of decreased tectonic activity. The oxygen concentration would then have been limited to about 4 x 10 to the -8th PAL by reaction with dissolved ferrous iron in the early oceans. The case 1 atmosphere is reducing, and the case 2 atmosphere oxidizing, based on the relative concentrations of reduced versus oxidized radical species present in the troposphere. The NO produced by lightning discharges is converted primarily to HNO in case 1 and to HNO3 in case 2.

  19. Osteosynthesis of ununited femoral neck fracture by internal fixation combined with iliac crest bone chips and muscle pedicle bone grafting

    PubMed Central

    Baksi, D D; Pal, A K; Baksi, D P

    2016-01-01

    Background: Ununited femoral neck fracture is seen commonly in developing countries due to delayed presentation or failure of primary internal fixation. Such fractures, commonly present with partial or total absorption of femoral neck, osteonecrosis of femoral head in 8–30% cases with upward migration of trochanter posing problem for osteosynthesis, especially in younger individuals. Several techniques for treatment of such conditions are described like osteotomies or nonvascularied cortical or cancellous bone grafting provided varying degrees of success in terms of fracture union but unsatisfactory long term results occurred due to varying incidence of avascular necrosis (AVN) of femoral head. Moreover, in presence of AVN of femoral head neither free fibular graft nor cancellous bone graft is satisfactory. The vascularied bone grafting by deep circumflex iliac artery based on iliac crest bone grafting, free vascularied fibular grafting and muscle pedicle periosteal grafting showed high incidence of success rate. Osteosynthesis is the preferred treatment of choice in ununited femoral neck fracture in younger individuals. Materials and Methods: Of the 293 patients operated during the period from June 1977 to June 2009, 42 were lost to followup. Seven patients with gluteus medius muscle pedicle bone grafting (MPBG) were excluded. Thus, out of 244 patients, 208 (85.3%) untreated nonunion and 36 (14.7%) following failure of primary internal fixation were available for studies. Time interval between the date of injury and operation in untreated nonunion cases was mean 6.5 months and in failed internal fixation cases was mean 11.2 months. Ages of the patients varied from 16 to 55 years. Seventy patients had partial and 174 had subtotal absorption of the femoral neck. Evidence of avascular necrosis (AVN) femoral head was found histologically in 135 (54.3%) and radiologically in 48 (19.7%) patients. The patients were operated by open reduction of fracture, cannulated hip

  20. Mechanical testing of internal fixation devices: A theoretical and practical examination of current methods.

    PubMed

    Grant, Caroline A; Schuetz, Michael; Epari, Devakar

    2015-11-26

    Successful healing of long bone fractures is dependent on the mechanical environment created within the fracture, which in turn is dependent on the fixation strategy. Recent literature reports have suggested that locked plating devices are too stiff to reliably promote healing. However, in vitro testing of these devices has been inconsistent in both method of constraint and reported outcomes, making comparisons between studies and the assessment of construct stiffness problematic. Each of the methods previously used in the literature were assessed for their effect on the bending of the sample and concordant stiffness. The choice of outcome measures used in in vitro fracture studies was also assessed. Mechanical testing was conducted on seven hole locked plated constructs in each method for comparison. Based on the assessment of each method the use of spherical bearings, ball joints or similar is suggested at both ends of the sample. The use of near and far cortex movement was found to be more comprehensive and more accurate than traditional centrally calculated interfragmentary movement values; stiffness was found to be highly susceptible to the accuracy of deformation measurements and constraint method, and should only be used as a within study comparison method. The reported stiffness values of locked plate constructs from in vitro mechanical testing is highly susceptible to testing constraints and output measures, with many standard techniques overestimating the stiffness of the construct. This raises the need for further investigation into the actual mechanical behaviour within the fracture gap of these devices. PMID:26477405

  1. Modern trends in internal fixation of femoral shaft fractures in children. A critical review.

    PubMed

    Parsch, K D

    1997-04-01

    Elastic intramedullary (IM) devices, which avoid the physeal region like Nancy and Ender nails do, can be used in children younger than even 4 years without compromising the trochanter physis or risking an avascular necrosis. Intramedullary fixation of femoral shaft fractures leads to satisfactory results of alignment and union. Prerequisites for intramedullary closed nailing are a traction table, especially for older children and adolescents, and an image intensifer. Interlocking IM, Ender, and Nancy nails all have the equal advantage of early weight bearing and reduced hospitalization time compared with traction and cast management. Küntscher or interlocking nails should only be used in adolescents close to the end of growth to avoid growth arrest of the trochanterocervical physis. Küntscher nails and interlocking IM nails are both associated with the small but troublesome risk of avascular necrosis. Ender and Nancy nails, with retrograde or antegrade pinning, have a low complication rate and a short learning curve for surgeons. Overgrowth in late controls after IM rodding of shaft fractures is about the same as the other types of treatment with an average overgrowth of 7 mm. Short hospital stay for children with IM nails reduces cost of treatment to about one half compared with in-hospital traction and cast management. PMID:9165440

  2. Biomechanical Evaluation of Four Methods for Internal Fixation of Comminuted Subtrochanteric Fractures

    PubMed Central

    Wang, Jie; Ma, Jian-xiong; Jia, Hao-bo; Chen, Yang; Yang, Yang; Ma, Xin-long

    2016-01-01

    Abstract Subtrochanteric fractures are common and result in significant morbidity and mortality. Various kinds of implants have been used to fix it. The aim of this study was to compare the biomechanical performance of PFN, DHS, DCS, and the PFLP in the treatment of subtrochanteric comminuted fractures. A total of 32 antiseptic human femurs from 16 donors were randomly allocated to 4 groups for fixation with PFN, DHS, DCS, and PFLP. A 2-cm cylindrical bone fragment was removed 1 cm below the lesser trochanter to simulate OTA/AO 32-C3.2 post instrumentation fracture. All specimens in single-leg stance situation were preloaded 5 times at 100 N in the axial direction to eliminate the time effect of relaxation and settling, followed by cyclic testing at a rate of 1 Hz with stepwise increasing load. Keeping the valley load at a constant level of 100 N during the entire cyclic test, the peak load, starting at 200 N, was increased by 100 N at 300-cycle steps until a maximum of 1500 cycles or until failure of the bone-implant construct occurred. Each specimen was kept unloaded under 100 N compression for 30 minutes between the 300-cycle steps. Femoral head displacement after 1500 cycles was 1.09 mm ± 0.13 for PFN, 1.78 mm ± 0.25 for DHS, 2.63 mm ± 0.46 for DCS, and 2.26 mm ± 0.16 for PFLP, with significant difference between any 2 implants (P < 0.01). The required load to reach 1-mm femoral head displacement was 563.04 N ± 158.34 for PFN, 485.73 N ± 147.27 for DHS, 258.44 N ± 97.23 for DCS, and 332.68 N ± 100.34 for PFLP. Significant differences were detected between any 2 implants (P < 0.001), except between DCS and PFLP and between DHS and PFN. The number of cycles until 1-mm femoral head displacement was 1458 ± 277 for PFN, 908 ± 184 for DHS, 369 ± 116 for DCS, and 603 ± 162 for PFLP. Significant differences were detected between any 2 implants (P < 0.01), except

  3. Biomechanical Evaluation of Four Methods for Internal Fixation of Comminuted Subtrochanteric Fractures.

    PubMed

    Wang, Jie; Ma, Jian-Xiong; Jia, Hao-Bo; Chen, Yang; Yang, Yang; Ma, Xin-Long

    2016-05-01

    Subtrochanteric fractures are common and result in significant morbidity and mortality. Various kinds of implants have been used to fix it. The aim of this study was to compare the biomechanical performance of PFN, DHS, DCS, and the PFLP in the treatment of subtrochanteric comminuted fractures.A total of 32 antiseptic human femurs from 16 donors were randomly allocated to 4 groups for fixation with PFN, DHS, DCS, and PFLP. A 2-cm cylindrical bone fragment was removed 1 cm below the lesser trochanter to simulate OTA/AO 32-C3.2 post instrumentation fracture. All specimens in single-leg stance situation were preloaded 5 times at 100 N in the axial direction to eliminate the time effect of relaxation and settling, followed by cyclic testing at a rate of 1 Hz with stepwise increasing load. Keeping the valley load at a constant level of 100 N during the entire cyclic test, the peak load, starting at 200 N, was increased by 100 N at 300-cycle steps until a maximum of 1500 cycles or until failure of the bone-implant construct occurred. Each specimen was kept unloaded under 100 N compression for 30 minutes between the 300-cycle steps.Femoral head displacement after 1500 cycles was 1.09 mm ± 0.13 for PFN, 1.78 mm ± 0.25 for DHS, 2.63 mm ± 0.46 for DCS, and 2.26 mm ± 0.16 for PFLP, with significant difference between any 2 implants (P < 0.01). The required load to reach 1-mm femoral head displacement was 563.04 N ± 158.34 for PFN, 485.73 N ± 147.27 for DHS, 258.44 N ± 97.23 for DCS, and 332.68 N ± 100.34 for PFLP. Significant differences were detected between any 2 implants (P < 0.001), except between DCS and PFLP and between DHS and PFN. The number of cycles until 1-mm femoral head displacement was 1458 ± 277 for PFN, 908 ± 184 for DHS, 369 ± 116 for DCS, and 603 ± 162 for PFLP. Significant differences were detected between any 2 implants (P < 0.01), except between DCS and

  4. Evaluation of three-dimensional printing for internal fixation of unstable pelvic fracture from minimal invasive para-rectus abdominis approach: a preliminary report

    PubMed Central

    Zeng, Canjun; Xiao, Jidong; Wu, Zhanglin; Huang, Wenhua

    2015-01-01

    Objective: The aim of this study is to evaluate the efficacy and feasibility of three-dimensional printing (3D printing) assisted internal fixation of unstable pelvic fracture from minimal invasive para-rectus abdominis approach. Methods: A total of 38 patients with unstable pelvic fractures were analyzed retrospectively from August 2012 to February 2014. All cases were treated operatively with internal fixation assisted by three-dimensional printing from minimal invasive para-rectus abdominis approach. Both preoperative CT and three-dimensional reconstruction were performed. Pelvic model was created by 3D printing. Data including the best entry points, plate position and direction and length of screw were obtained from simulated operation based on 3D printing pelvic model. The diaplasis and internal fixation were performed by minimal invasive para-rectus abdominis approach according to the optimized dada in real surgical procedure. Matta and Majeed score were used to evaluate currative effects after operation. Results: According to the Matta standard, the outcome of the diaplasis achieved 97.37% with excellent and good. Majeed assessment showed 94.4% with excellent and good. The imageological examination showed consistency of internal fixation and simulated operation. The mean operation time was 110 minutes, mean intraoperative blood loss 320 ml, and mean incision length 6.5 cm. All patients have achieved clinical healing, with mean healing time of 8 weeks. Conclusion: Three-dimensional printing assisted internal fixation of unstable pelvic fracture from minimal invasive para-rectus abdominis approach is feasible and effective. This method has the advantages of trauma minimally, bleeding less, healing rapidly and satisfactory reduction, and worthwhile for spreading in clinical practice. PMID:26550226

  5. Does Extraction or Retention of the Wisdom Tooth at the Time of Surgery for Open Reduction and Internal Fixation of the Mandible Alter the Patient Outcome?

    PubMed

    Hammond, Douglas; Parmar, Sat; Whitty, Justin; Pigadas, Nick

    2015-12-01

    Whether to extract or retain wisdom teeth present in a fracture line is a controversial topic. This study reviewed the records of all patients who had mandibular wisdom teeth at the time of the injury, and had an open reduction and internal fixation procedure between January 2009 and January 2012. The cohort of patients who concomitantly had their wisdom tooth extracted at the time of fixation had a greater complication rate (24.3%) compared with patients who did not (14.9%). This suggests that if third molars in the line of a fracture have caries, are fractured, show signs of pericoronitis, are periodontally involved, or are interfering with the occlusion are extracted at the time of fixation, this will increase the incidence of complications. PMID:26576231

  6. Biomechanical comparison of three types of internal fixation in a type C zone II pelvic fracture model

    PubMed Central

    Wu, Tao; Chen, Wei; Li, Xu; Zhang, Qi; Lv, Hong-Zhi; Zhang, Ying-Ze

    2015-01-01

    Objective: This study aimed to compare the stability of Tile C pelvic fractures fixed with two iliosacral (IS) screws, tension band plate (TBP), and minimally invasive adjustable plate (MIAP). Methods: Six embalmed specimens of adult pelvis were used. The soft tissue was removed from the specimens, but spines from the fourth lumbar vertebra to the proximal one-third of both femurs were retained. The pubic symphysis, bilateral sacroiliac joints and ligaments, bilateral hip joints, bilateral sacrotuberous ligaments, and bilateral sacrospinous ligaments were intact. Tile C pelvic fractures were created on the specimens. The symphysis pubis was fixed with a plate, and the fracture on the posterior pelvic ring was fixed with three types of internal fixation in a randomized block design. The specimens were placed in a biomechanical machine at a standing neutral posture. A cyclic vertical load of up to 500N was applied, and displacement was recorded. Shifts in the fracture gap were measured by a grating displacement sensor. Results: Under different vertical loads, the shift in the fracture gap and displacement of the pelvic fractures fixed with two IS screws were similar to those in fractures fixed with MIAP. However, the shift in the fracture gap and displacement of fractures fixed with MIAP was significantly smaller than those of fractures fixed with TBP. Conclusion: The stability of the Tile C pelvic fractures fixed with MIAP was similar to that of fractures fixed with IS screws. MIAP performed better than TBP under vertical load. PMID:25932113

  7. Clinical results of reversed V-shaped high tibial corticotomy with minimally invasive surgery without internal fixation devices.

    PubMed

    Madadi, Firooz; Eajazi, Alireza; Madadi, Firoozeh; Daftari Besheli, Laleh; Rokni, Reza; Abbasian, Mohammad Reza; Bigdeli, Mohammad Reza

    2010-06-01

    High tibial osteotomy is a method of treating knee osteoarthritis due to genu varum in advanced stages. High tibial osteotomy-associated problems continue to be reported. The purpose of this study was to investigate the clinical results of a new, innovative method of high tibial osteotomy with 3- to 13-year follow-up. Between 1996 and 2006, our new surgical method was performed on 293 patients with medial compartment osteoarthritis and genu varum. All patients were examined preoperatively, 6 months postoperatively, and at final follow-up. The Hospital for Special Surgery Knee Scoring System (HSS) was used at final follow-up, and limb alignment and patient satisfaction were reassessed. Immediate postoperative complications included varus recurrence, knee instability, and peroneal nerve palsy, and no signs of tibial nonunion or infection were observed. At final follow-up, 3 cases of genu recurvatum, 2 cases of peroneal nerve palsy, and 25 cases of loss of correction were observed. Average postoperative HSS score was 85 (range, 47-97), and 97.8% of the patients were satisfied. This new method is a good alternative for the correction of genu varum because it requires a small incision, is soft tissue friendly, is a corticotomy instead of an osteotomy, requires no internal or external fixation devices, has a shorter duration and an acceptable complication and recurrence rate, and results in satisfactory HSS scores and higher patient satisfaction rates. PMID:20806771

  8. Biomechanical in vitro evaluation of three stable internal fixation techniques used in sagittal osteotomy of the mandibular ramus: a study in sheep mandibles

    PubMed Central

    de OLIVERA, Leandro Benetti; SANT'ANA, Eduardo; MANZATO, Antonio José; GUERRA, Fábio Luis Bunemer; ARNETT, G. William

    2012-01-01

    Among the osteotomies performed in orthognathic surgery, the sagittal osteotomy of the mandibular ramus (SOMR) is the most common, allowing a great range of movements and stable internal fixation (SIF), therefore eliminating the need of maxillomandibular block in the postoperative period. Objectives: The purpose of this study was to evaluate the biomechanical resistance of three national systems used for SIF in SOMR in sheep mandibles. Material and methods: The study was performed in 30 sheep hemi-mandibles randomly divided into 3 experimental groups, each containing 10 hemi-mandibles. The samples were measured to avoid discrepancies and then subjected to SOMR with 5-mm advancement. In group I, 2.0x12 mm screws were used for fixation, inserted in an inverted "L" pattern (inverted "L" group). In group II, fixation was performed with two 2.0x12 mm screws, positioned in a linear pattern and a 4-hole straight miniplate and four 2.0x6.0 mm monocortical screws (hybrid group). In group III, fixation was performed with two 4-hole straight miniplates and eight 2.0x6.0 mm monocortical screws (mini plate group). All materials used for SIF were supplied by Osteosin - SIN. The hemimandibles were subjected to vertical linear load test by Kratos K2000MP mechanical testing unit for loading registration and displacement. Results: All groups showed similar resistance during mechanical test for loading and displacement, with no statistically significant differences between groups according to analysis of variance. Conclusion: These results indicate that the three techniques of fixation are equally effective for clinical fixation of SOMR. PMID:23032203

  9. Biomechanical Comparison of Two Kinds of Internal Fixation in a Type C Zone II Pelvic Fracture Model

    PubMed Central

    Wu, Tao; Chen, Wei; Zhang, Qi; Zheng, Zhan-Le; Lyu, Hong-Zhi; Cui, Yun-Wei; Cheng, Xiao-Dong; Zhang, Ying-Ze; Yang, Yan-Jiang

    2015-01-01

    Background: Unstable pelvic fractures are complex and serious injuries. Selection of a fixation method for these fractures remains a challenging problem for orthopedic surgeons. This study aimed to compare the stability of Tile C pelvic fractures fixed with two iliosacral (IS) screws and minimally invasive adjustable plate (MIAP) combined with one IS screw. Methods: This study was a biomechanical experiment. Six embalmed specimens of the adult pelvis were used. The soft tissue was removed from the specimens, and the spines from the fourth lumbar vertebra to the proximal one-third of both femurs were retained. The pubic symphysis, bilateral sacroiliac joints and ligaments, bilateral hip joints, bilateral sacrotuberous ligaments, and bilateral sacrospinous ligaments were intact. Tile C pelvic fractures were made on the specimens. The symphysis pubis was fixed with a plate, and the fracture on the posterior pelvic ring was fixed with two kinds of internal fixation in turn. The specimens were placed in a biomechanical machine at a standing neutral posture. A cyclic vertical load of up to 500 N was applied, and displacement was recorded. Shifts in the fracture gap were measured by a grating displacement sensor. Statistical analysis used: Paired-samples t-test. Results: Under the vertical load of 100, 200, 300, 400, and 500 N, the average displacement of the specimens fixed with MIAP combined with one IS screw was 0.46, 0.735, 1.377, 1.823, and 2.215 mm, respectively, which was significantly lower than that of specimens fixed with two IS screws under corresponding load (P < 0.05). Under the vertical load of 500 N, the shift in the fracture gap of specimens fixed with MIAP combined with one IS screw was 0.261 ± 0.095 mm, and that of specimens fixed with two IS screws was 0.809 ± 0.170 mm. The difference was significant (P < 0.05). Conclusion: The stability of Tile C pelvic fractures fixed with MIAP combined with one IS screw was better than that fixed with two IS screws

  10. Limited Unilateral Decompression and Pedicle Screw Fixation with Fusion for Lumbar Spinal Stenosis with Unilateral Radiculopathy: A Retrospective Analysis of 25 Cases

    PubMed Central

    Zhang, Li; Miao, Hai-xiong; Wang, Yong; Chen, An-fu; Zhang, Tao

    2015-01-01

    Objective Lumbar spinal stenosis is conventionally treated with surgical decompression. However, bilateral decompression and laminectomy is more invasive and may not be necessary for lumbar stenosis patients with unilateral radiculopathy. We aimed to report the outcomes of unilateral laminectomy and bilateral pedicle screw fixation with fusion for patients with lumbar spinal stenosis and unilateral radiculopathy. Methods Patients with lumbar spinal stenosis with unilateral lower extremity radiculopathy who received limited unilateral decompression and bilateral pedicle screw fixation were included and evaluated using visual analog scale (VAS) pain and the Oswestry Disability Index (ODI) scores preoperatively and at follow-up visits. Ligamentum flavum thickness of the involved segments was measured on axial magnetic resonance images. Results Twenty-five patients were included. The mean preoperative VAS score was 6.6±1.6 and 4.6±3.1 for leg and back pain, respectively. Ligamentum flavum thickness was comparable between the symptomatic and asymptomatic side (p=0.554). The mean follow-up duration was 29.2 months. The pain in the symptomatic side lower extremity (VAS score, 1.32±1.2) and the back (VAS score, 1.75±1.73) significantly improved (p=0.000 vs. baseline for both). The ODI improved significantly postoperatively (6.60±6.5; p=0.000 vs. baseline). Significant improvement in VAS pain and ODI scores were observed in patients receiving single or multi-segment decompression fusion with fixation (p<0.01). Conclusion Limited laminectomy and unilateral spinal decompression followed by bilateral pedicle screw fixation with fusion achieves satisfactory outcomes in patients with spinal stenosis and unilateral radiculopathy. This procedure is less damaging to structures that are important for maintaining posterior stability of the spine. PMID:26279816

  11. Comparison of modified Thiel embalming and ethanol-glycerin fixation in an anatomy environment: Potentials and limitations of two complementary techniques.

    PubMed

    Hammer, Niels; Löffler, Sabine; Bechmann, Ingo; Steinke, Hanno; Hädrich, Carsten; Feja, Christine

    2015-01-01

    Thiel-fixed specimens have outstandingly lifelike visual and haptic properties. However, the original Thiel method is expensive and requires an elaborate setup. It is therefore of principal interest to modify the Thiel method in order to make it available to a broader user group. A modified Thiel embalming method will be described in detail and compared to ethanol-glycerin fixation with the help of illustrative examples. The visual properties, haptic properties, the usability for performing histological investigations, costs and potential health aspects will be considered. Tissues fixed with the modified Thiel technique gave results similar to the original method, providing more realistic visual and haptic properties than ethanol-glycerin embalming. However, Thiel fixation is significantly more expensive and requires more precautions to minimize potential health hazards than ethanol-glycerin-fixed tissues. In contrast to ethanol-glycerin-fixed specimens, the Thiel-fixed specimens are not suitable for histological investigations. Both modes of fixation are inappropriate for biomechanical testing. Modified Thiel embalming simplifies the availability of body donors with lifelike properties and has cost-saving advantages to the original technique. Thiel-embalmed body donors are ideally suited for clinical workshops but have restrictions for student dissection courses in facilities with limited storage space, air circulation or technical staff. Vice versa, ethanol-glycerin-fixed body donors are well suited for student dissection courses in such an environment but are limited in their use for clinical workshops. Modified Thiel embalming therefore ideally complements ethanol-glycerin fixation in order to provide customized solutions for clinical workshops and student dissection courses in a wide range of applications. PMID:24706536

  12. The successes and limitations of international law and the International Court of Justice.

    PubMed

    Suter, Keith

    2004-01-01

    The first two sections of this article deal with the irony that international law has severe limitations, yet it also has a good record for compliance. The third section introduces the International Court of Justice (ICJ), and the fourth section deals specifically with the limitations of the ICJ. The article concludes with some ideas for action. Its main point is that international law is often a neglected topic, even by non-governmental organisations (NGOs). International law needs to be brought in from the cold, and there should be more support from the NGO community for the ICJ. PMID:15688885

  13. Prophylactic radiotherapy against heterotopic ossification following internal fixation of acetabular fractures: a comparative estimate of risk

    PubMed Central

    Nasr, P; Yip, G; Scaife, J E; House, T; Thomas, S J; Harris, F; Owen, P J; Hull, P

    2014-01-01

    Objective: Radiotherapy (RT) is effective in preventing heterotopic ossification (HO) around acetabular fractures requiring surgical reconstruction. We audited outcomes and estimated risks from RT prophylaxis, and alternatives of indometacin or no prophylaxis. Methods: 34 patients underwent reconstruction of acetabular fractures through a posterior approach, followed by a 8-Gy single fraction. The mean age was 44 years. The mean time from surgery to RT was 1.1 days. The major RT risk is radiation-induced fatal cancer. The International Commission on Radiological Protection (ICRP) method was used to estimate risk, and compared with a method (Trott and Kemprad) specifically for estimating RT risk for benign disease. These were compared with risks associated with indometacin and no prophylaxis. Results: 28 patients (82%) developed no HO; 6 developed Brooker Class I; and none developed Class II–IV HO. The ICRP method suggests a risk of fatal cancer in the range of 1 in 1000 to 1 in 10,000; the Trott and Kemprad method suggests 1 in 3000. For younger patients, this may rise to 1 in 2000; and for elderly patients, it may fall to 1 in 6000. The risk of death from gastric bleeding or perforation from indometacin is 1 in 180 to 1 in 900 in older patients. Without prophylaxis risk of death from reoperation to remove HO is 1 in 4000 to 1 in 30,000. Conclusion: These results are encouraging, consistent with much larger series and endorse our multidisciplinary management. Risk estimates can be used in discussion with patients. Advances in knowledge: The risk from RT prophylaxis is small, it is safer than indometacin and substantially overlaps with the range for no prophylaxis. PMID:25089852

  14. Effects of Low-Dose Microwave on Healing of Fractures with Titanium Alloy Internal Fixation: An Experimental Study in a Rabbit Model

    PubMed Central

    Zhang, Han; Fu, Tengfei; Jiang, Lan; Bai, Yuehong

    2013-01-01

    Background Microwave is a method for improving fracture repair. However, one of the contraindications for microwave treatment listed in the literature is surgically implanted metal plates in the treatment field. The reason is that the reflection of electromagnetic waves and the eddy current stimulated by microwave would increase the temperature of magnetic implants and cause heat damage in tissues. Comparing with traditional medical stainless steel, titanium alloy is a kind of medical implants with low magnetic permeability and electric conductivity. But the effects of microwave treatment on fracture with titanium alloy internal fixation in vivo were not reported. The aim of this article was to evaluate the security and effects of microwave on healing of a fracture with titanium alloy internal fixation. Methods Titanium alloy internal fixation systems were implanted in New Zealand rabbits with a 3.0 mm bone defect in the middle of femur. We applied a 30-day microwave treatment (2,450MHz, 25W, 10 min per day) to the fracture 3 days after operation. Temperature changes of muscle tissues around implants were measured during the irradiation. Normalized radiographic density of the fracture gap was measured on the 10th day and 30th day of the microwave treatment. All of the animals were killed after 10 and 30 days microwave treatment with histologic and histomorphometric examinations performed on the harvested tissues. Findings The temperatures did not increase significantly in animals with titanium alloy implants. The security of microwave treatment was also supported by histology of muscles, nerve and bone around the implants. Radiographic assessment, histologic and histomorphometric examinations revealed significant improvement in the healing bone. Conclusion Our results suggest that, in the healing of fracture with titanium alloy internal fixation, a low dose of microwave treatment may be a promising method. PMID:24086626

  15. The injuries to the fourth and fifth tarsometatarsal joints: A review of the surgical management by internal fixation, arthrodesis and arthroplasty

    PubMed Central

    Yu, Xiao; Pang, Qing-jiang; Yu, Guang-rong

    2013-01-01

    The surgical management to the injuries of the fourth and fifth tarsometatarsal (TMT) joints is controversial. We briefly review the anatomical characteristics to the injuries, the diagnosis, as well as the individualized treatment of the injuries of the fourth and fifth TMT joints by open reduction and internal fixation, TMT arthrodesis and arthroplasty. We conclude that open reduction and internal fixation is the recommended option for acute injuries, while arthrodesis can be used in cases of malunion of the fourth and fifth TMT joints with gross pain or arthritic changes and obvious structural deformity. Arthroplasty is an effective salvage operation mainly used in high-demand patients with severe TMT arthritis. Finally, we propose a recommended treatment algorithm (based on the literature and our experience), taking into account the specific indications for internal fixation, TMT arthrodesis and arthroplasty to optimize the individualized treatment. Data sources/Study selection Data from survey reports, descriptive, cross-sectional and longitudinal studies published from 2002 to 2012 on the topic of the injuries to the fourth and fifth tarsometatarsal joint on human and radiography studies were included. Data Extraction The data was extracted from online resources of American Orthopaedic Foot & Ankle Society, American Academy of Orthopaedic Surgeons, US National Library of Medicine, The MEDLINE. Conclusion It is important to comprehend the specific anatomical characteristics and grasp the strict indications, advantages and disadvantages of the ORIF, TMT arthrodesis and arthroplasty to optimize the individualized treatment of the fourth and fifth TMT joints injuries in a maximum extent. PMID:24353608

  16. A comparative study of internal fixation and prosthesis replacement for radial head fractures of Mason type III

    PubMed Central

    Ruan, Hong-Jiang; Liu, Jun-Jian; Zeng, Bing-fang

    2007-01-01

    Although several treatment options for radial head fractures are available, no clear solutions exist. In this study we therefore compare open reduction and internal fixation (ORIF) with bipolar radial head prosthesis replacement in treatment of radial head fractures of Mason type III. Cement stem and bipolar radial prosthesis were used to treat 12 fresh cases and two old cases of Mason type III radial head fracture. As a control group, another eight cases of radial head type III fracture were treated with ORIF with cannulated screws and Kirschner (K) wires. The 14 patients who received radial head prosthesis replacement were followed-up for 15.9 months (range 10–27 months). According to elbow functional evaluation criteria by Broberg and Morrey, we found excellent results in nine cases, good in four, and fair in one. Mean follow-up of the eight cases in the ORIF group was 14 months (range 10–21 months), with good results in one case, fair in four, and poor in three. The result was good or excellent in 92.9% of prosthesis replacement patients and in 12.5% of ORIF patients. This difference is statistically significant (P = 0.0004; Fisher’s exact test). We concluded that bipolar radial head prosthesis replacement is better than ORIF in treatment of Mason type III radial head fracture. Electronic Supplementary Material The online version of this article (doi:10.1007/s00264-007-0453-3) contains supplementary material, which is available to authorized users. PMID:17938924

  17. The Correlation between the Fracture Types and the Complications after Internal Fixation of the Femoral Neck Fractures

    PubMed Central

    Jo, Suenghwan; Lee, Hyeon Jun

    2016-01-01

    Purpose This study aims to determine the correlation between the fracture patterns and the complications in patients with femoral neck fracture treated with internal fixation. Materials and Methods The study comprises 45 patients with femoral neck fracture treated with multiple screws or compression hip screw between May 2008 and April 2012. The mean age was 48 years at the time of the surgery and the mean duration from initial injury to surgery was 20 hours. The fracture patterns were identified according to the anatomical location, the Garden classification and the Pauwels classification. The occurrence of nonunion and avascular necrosis were reviewed with clinical results including Harris hip score and Lunceford hip function test. The correlation between the fracture pattern and occurrence of complications were analyzed. Results Fracture site union was achieved in 40 hips with the average union time of 17 weeks. Five nonunions occurred which showed high likelihood to occur in subcapital type, displaced (Garden stage III or IV) and Pauwels type III fractures (P<0.05). Avascular necrosis was developed in 10 hips which was mostly in subcapital type and Pauwels type III fracture but no statistical significance was found (P>0.05). The mean Harris hip score was 91 points, and Lunceford functional results were excellent in 15 hips, good in 24, fair in 4 and poor in 2. Conclusion There was high risk of nonunion in subcapital type fracture, displaced fracture (Garden stage III and IV) and vertically oriented fracture (Pauwels type III). Careful attention is needed in these fracture types.

  18. Outcomes of anterolateral thigh-free flaps and conversion from external to internal fixation with bone grafting in gustilo type IIIB open tibial fractures.

    PubMed

    Lee, Jae Hoon; Chung, Duke Whan; Han, Chung Soo

    2012-09-01

    The purpose of this study was to analyze the utility and the clinical outcomes of anterolateral thigh (ALT)-free flaps and conversion from external to internal fixation with plating and bone grafting in Gustilo type IIIB open tibial fractures. A total of 21 patients were analyzed retrospectively. The mean follow-up period was 18 months and the mean age was 46.7 years. There were 18 men and three women. The mean time from injury to flap coverage was 11.6 days. The mean size of flaps used was 15.3 × 8.2 cm. The mean size of bone defects was 2.26 cm. Segmental bone defects were observed in 5 five cases, for which bone transport or vascularized fibular graft were performed. When flaps were successful and the fracture sites did not have any evidence of infection, internal fixation with plates and bone grafting were performed. Flaps survived in 20 cases. In the 20 cases with successful flaps, two cases developed osteomyelitis, but the 20 cases achieved solid bone union at a mean of 8.6 months after the injury, salvaging the lower extremity in 100% of the cases. At the last follow-up, 9 nine cases were measured excellent or good; 6, fair; and 6, poor in the functional assessment based on the method developed by Puno et al. ALT- free flaps to cover soft tissue defects in Gustilo type IIIB open tibial fractures are considered as useful option for the treatment of composite defects. In addition, conversion to internal fixation and bone grafting can be an alternative method in order to reduce the risk of complications and inconvenience of external fixators. PMID:22434519

  19. Inverted Internal Limiting Membrane Flap For Large Traumatic Macular Holes.

    PubMed

    Abou Shousha, Mohsen Ahmed

    2016-01-01

    The aim of the study was to assess the role of inverted internal limiting membrane flap as a treatment option for large traumatic macular holes.This is a prospective noncomparative study in which 12 eyes with large traumatic macular holes (basal diameter of 1300-2800 μm) since 3 to 6 months were subjected to standard 23-gauge vitrectomy with removal of the posterior hyaloid, brilliant blue G (BBG)-assisted internal limiting membrane peeling in a circular fashion keeping it attached to the edge of the hole to create a flap. At the end of the surgery, air fluid exchange was done with inversion of the internal limiting membrane flap inside the macular hole using the soft tipped cannula and sulfur hexafluoride 20% as tamponade. The main follow-up measures are the best corrected visual acuity and the optical coherence tomography for 6 to 9 months.All the included eyes had a closed hole from the first week postoperative and along the follow-up period (6-9 months). The best corrected visual acuity improved from 20/2000 to 20/200 with a median of 20/400 preoperatively to 20/400 to 20/50 with a median of 20/100 at the end of follow-up period.Inverted internal limiting membrane flap is a good adjuvant to standard vitrectomy in the management of large traumatic macular holes that led to the 100% closure rate and improvement of best corrected visual acuity. PMID:26817894

  20. Burnei’s “double X" internal fixation technique for supracondylar humerus fractures in children: indications, technique, advantages and alternative interventions

    PubMed Central

    Georgescu, I; Gavriliu, S; Pârvan, A; Martiniuc, A; Japie, E; Ghiță, R; Drăghici, I; Hamei, S; Ţiripa, I; El Nayef, T; Dan, D

    2013-01-01

    Background. The Study and Research Group in Pediatric Orthopedics-2012 initated this retrospective study due to the fact that in Romania and in other countries, the numerous procedures do not ensure the physicians a definite point of view related to the therapeutic criteria in the treatment of supracondylar fractures. That is why the number of complications and their severity brought into notice these existent deficiencies. In order to correct some of these complications, cubitus varus or valgus, Prof. Al. Pesamosca communicated a paper called "Personal procedure in the treatment of posttraumatic cubitus varus" at the County Conference from Bacău, in June 24, 1978. This procedure has next been made popular by Prof. Gh. Burnei and his coworkers by operating patients with cubitus varus or valgus due to supracondylar humeral fractures and by presenting papers related to the subject at the national and international congresses. The latest paper regarding this problem has been presented at the 29th Annual Meeting of the European Pediatric Orthopedic Society in Zagreb, Croatia, April 7-10, 2010, being titled “Distal humeral Z-osteotomy for posttraumatic cubitus varus or valgus", having as authors Gh. Burnei, Ileana Georgescu, Ştefan Gavriliu, Costel Vlad and Daniela Dan. As members of this group, based on the performed studies, we wish to make popular this type of osteosynthesis, which ensures a tight fixation, avoids complications and allows a rapid postoperative activity. Introduction. The acknowledged treatment for these types of fractures is the orthopedic one and it must be accomplished as soon as possible, in the first 6 hours, by reduction and cast immobilization or by closed or open reduction and fixation, using one of the several methods (Judet, Boehler, Kapandji, San Antonio, San Diego, Burnei’s double X technique). The exposed treatment is indicated in irreducible supracondylar humeral fractures, in reducible, but unstable type, in polytraumatized

  1. Long-term growth and alignment after occipitocervical and atlantoaxial fusion with rigid internal fixation in young children.

    PubMed

    Kennedy, Benjamin C; D'Amico, Randy S; Youngerman, Brett E; McDowell, Michael M; Hooten, Kristopher G; Couture, Daniel; Jea, Andrew; Leonard, Jeffrey; Lew, Sean M; Pincus, David W; Rodriguez, Luis; Tuite, Gerald F; Diluna, Michael L; Brockmeyer, Douglas L; Anderson, Richard C E

    2016-01-01

    of these growth patterns or alignment were evident. CONCLUSIONS These results demonstrate that most young children undergoing AA and OC fusion with rigid internal fixation continue to have good cervical alignment and continued growth within the fused levels during a prolonged follow-up period. However, some variability in vertical growth and alignment exists, highlighting the need to continue close long-term follow-up. PMID:26451720

  2. Wedgeless 'V' shaped distal femoral osteotomy with internal fixation for genu valgum in adolescents and young adults.

    PubMed

    Gupta, Vikas; Kamra, Gaurav; Singh, Davinder; Pandey, Ketan; Arora, Sumit

    2014-06-01

    The treatment of angular malalignment includes restoration of normal mechanical axis alignment and joint orientation.The supracondylar wedgeless distal femoral 'V' osteotomy, as a treatment modality, is sparsely explored in the literature. This study was conducted at a tertiary level teaching referral hospital from October 2010 to September 2012. Forty six lower limbs (in 30 patients) were operated with a wedgeless 'V' osteotomy that was fixed with a buttress 'L' plate. The pre-operative deformity, post-operative correction and knee range of movement were noted. Mobilisation was started at 3 weeks after surgery and full weight-bearing was allowed at 3 months. The knee score by Bostman et al. was used for functional outcome. The mean age of the patients in our study was 16.9 years (range: 15 years to 23 years). The patients were followed up for a mean period of 19.8 months (range, 15 months to 29 months). The mean radiological tibiofemoral angle was 22.2 degrees (range, 16 degrees to 29 degrees) before surgery, that improved to a mean postoperative value of 5.1 degrees (range, 0 degrees to 10 degrees) (p < 0.001). The mean preoperative lateral distal femoral angle was 79.23 degrees that improved to a mean value of 89.13 degrees after surgery (p < 0.001). The mean mechanical axis deviation was 19.56 mm before surgery that improved to a mean postoperative value of 3.7 mm (p < 0.001). All patients reached a correction of the deformity and 44 cases out of a total of 46 had an excellent functional outcome, 2 patients had a good functional outcome. None had an unsatisfactory outcome. Two cases had a deep wound infection that subsided after implant removal. None of the cases had other complications. The distal femoral 'V' shaped osteotomy is a simple procedure for the correction of genu valgum in individuals nearing skeletal maturity and is easy to perform. It has the advantage of being wedgeless as it does not cause limb length discrepancy. Internal fixation helps in

  3. A 1-piece shape-metal nitinol intramedullary internal fixation device for arthrodesis of the proximal interphalangeal joint in neuropathic patients with diabetes.

    PubMed

    Roukis, Thomas S

    2009-06-01

    A common complication associated with diabetes is the development of a rigid structural lesser toe contracture, which, when combined with peripheral sensory neuropathy, can lead to ulceration, infection, and amputation. Surgical correction of lesser toe contractures in persons with diabetes has been advocated to decrease the potential for ulceration and amputation. Lesser toe proximal interphalangeal joint arthrodesis employing myriad joint preparation and fixation methods is commonly performed to correct a rigid structural toe contracture. The author performed a retrospective, observational, cohort study involving 10 patients (30 toes) with diabetes, dense peripheral neuropathy, and rigid structural toe contracture treated with a 1-piece shape-memory Nitinol intramedullary internal fixation device for arthrodesis of the proximal interphalangeal joint. Successful fusion was achieved in 28 of 30 toes (93%), with a stable nonunion achieved in the remainder. Complications that arose occurred early in the author's experience with this implant and consisted of secondary contracture of the distal interphalangeal joint (23%), displaced fixation (13%), and malunion (7%). No patient developed ulceration, and no additional surgery has been required to date. When properly performed, the use of this implant for arthrodesis of the proximal interphalangeal joint in neuropathic patients with diabetes appears safe and reliable. PMID:19825764

  4. Open reduction and internal fixation of extracapsular mandibular condyle fractures: a long-term clinical and radiological follow-up of 25 patients

    PubMed Central

    2014-01-01

    Background During the last 2 decades, many studies on the treatment of mandibular condyle fracture have been published. The incidence of mandibular condyle fractures is variable, ranging from 17.5% to 52% of all mandibular fractures. This retrospective study evaluated the long-term clinical and radiological outcomes after surgical treatment of 25 patients with a total of 26 extracapsular condyle fractures. Methods We used 2 types of surgical approaches, the retromandibular retroparotid or preauricular approach. Three kinds of rigid internal fixation plates were used—single plate, double plate, and trapezoidal plate. The following post-operative clinical parameters were evaluated: dental occlusion, facial nerve functionality, skin scarring, and temporomandibular joint functionality. All patients underwent post-operative orthopanoramic radiography and computed tomography. The patients were also monitored for complications such as Frey’s syndrome, infection, salivary fistula, plate fracture, and permanent paralysis of the facial nerve; the patient’s satisfaction was also recorded. Results Of the 25 patients, 80% showed occlusion recovery, 88% had no facial nerve injury, and 88% presented good surgical skin scarring. The patients showed early complete recovery of temporomandibular joint functionality and 72% of them were found to be asymptomatic. The postoperative radiographs of all patients indicated good recovery of the anatomical condylar region, and 80% of them had no postoperative complications. The average degree of patient satisfaction was 8.32 out of 10. Our results confirm that the technique of open reduction and internal fixation in association with postoperative functional rehabilitation therapy should be considered for treating patients with extracapsular condylar fractures. Conclusion The topic of condylar injury has generated more discussion and controversy than any other topic in the field of maxillofacial trauma. We confirm that open reduction and

  5. Combined medial column primary arthrodesis, middle column open reduction internal fixation, and lateral column pinning for treatment of Lisfranc fracture-dislocation injuries.

    PubMed

    Boffeli, Troy J; Pfannenstein, Ryan R; Thompson, Jonathan C

    2014-01-01

    Lisfranc fracture-dislocation can be a devastating injury with significant long-term sequelae, including degenerative joint disease, progressive arch collapse, and chronic pain that can be potentiated if not effectively treated. We present a case to demonstrate our preferred surgical approach, consisting of combined medial column primary arthrodesis, middle column open reduction internal fixation, and lateral column pinning, with the primary goal of minimizing common long-term complications associated with Lisfranc injuries. We present the case of a typical patient treated according to this combined surgical approach to highlight our patient selection criteria, rationale, surgical technique, and operative pearls. A 36-year-old male who had sustained a homolateral Lisfranc fracture-dislocation injury after falling from a height initially underwent fasciotomy for foot compartment syndrome. The subsequent repair 16 days later involved primary first tarsometatarsal joint fusion, open reduction internal fixation of the second and third tarsometatarsal joints, and temporary pinning of the fourth and fifth tarsometatarsal joints. He progressed well postoperatively, exhibiting an American College of Foot and Ankle Surgeons forefoot score of 90 of 100 at 1 year after surgery with no need for subsequent treatment. Lisfranc fracture-dislocations often exhibit primary dislocation to the medial column and are conducive to arthrodesis to stabilize the tarsometatarsal complex. The middle column frequently involves comminuted intra-articular fractures and will often benefit from less dissection required for open reduction internal fixation instead of primary fusion. We propose that this surgical approach is a viable alternative technique for primary treatment of Lisfranc fracture-dislocation injuries. PMID:24846158

  6. The Immediate Effects of Different Types of Ankle Support Introduced 6 Weeks After Surgical Internal Fixation for Ankle Fracture on Gait and Pain: A Randomized Crossover Trial.

    PubMed

    Keene, David J; Willett, Keith; Lamb, Sarah E

    2016-03-01

    Study Design Randomized 3-treatment, 3-period crossover trial. Background There is variation in clinical practice regarding the type of ankle support used to aid recovery after ankle fracture internal fixation surgery. Objective To determine the immediate effects of different ankle supports commonly issued to patients 6 weeks after surgery. Methods Participants were 18 adults, 6 weeks after internal fixation for transsyndesmotic/infrasyndesmotic fracture, in a major trauma center in the UK. Interventions were a stirrup brace and walker boot compared with Tubigrip. Outcomes were (1) step-length and single-limb support time asymmetry (percentage comparing injured and uninjured limbs), (2) step width, (3) gait velocity, and (4) pain during walking (visual analog scale, 0-100). Results Participants (mean ± SD age, 47 ± 14 years) included 8 women and 10 men, 6 weeks after surgical internal fixation for ankle fracture. Single-limb support time asymmetry reduced by 3% (95% confidence interval [CI]: 0%, 6%; P = .02) in the stirrup brace and by 5% (95% CI: 2%, 7%; P = .001) in the walker boot compared with Tubigrip. Step width was 1.2 cm (95% CI: 0.6, 1.7; P<.001) wider in the walker boot than in Tubigrip. Self-reported pain was lower in the walker boot (5/100) and in the stirrup brace (13/100) compared to the Tubigrip (18/100, P = .03). No significant differences were found in the effects of the supports on step-length asymmetry between the walker boot or stirrup brace and Tubigrip. Conclusion At 6 weeks after surgical internal fixation for ankle fracture, pain and single-limb support time asymmetry over a short distance and for a short-term walk were immediately reduced with the use of a walker boot use and, to a lesser extent, a stirrup-brace compared to Tubigrip. Step width also widened in a walker boot, which may confer some additional gait stability. These results apply to immediate effects, so studies with longer-term follow-up are now indicated. The trial was

  7. Expansive Open-Door Cervical Laminoplasty: In Situ Reconstruction of Extensor Muscle Insertion on the C2 Spinous Process Combined With Titanium Miniplates Internal Fixation

    PubMed Central

    Cheng, Zhaohui; Chen, Weishan; Yan, Shigui; Li, Wanli; Qian, Shengjun

    2015-01-01

    Abstract Retrospective cohort study. To evaluate efficacy and relevant problems of in situ reconstruction of extensor muscle insertion on the C2 spinous process combined with titanium miniplates internal fixation in expansive open-door cervical laminoplasty in order to improve surgical treatment effect. Expansive open-door cervical laminoplasty has been widely applied in clinical practice, but there are a series of postoperative problems. Therefore, decreasing postoperative complications in order to more effectively relieve symptoms remains a subject for additional research. From October 2011 to September 2013, a total of 60 patients who suffered cervical canal stenosis were treated by expansive open-door laminoplasty with in situ reconstruction of extensor muscle insertion on the C2 spinous process combined with titanium miniplates internal fixation. Changes of cervical curvature index (CI) and range of motion (ROM) were calculated using data from preoperative and postoperative cervical spine X-ray examinations. Clinical function was scored using the Japanese Orthopedics Association Scoring System (JOA) and the neck disability index (NDI). The mean CI before the operation and at 1-year postoperation were 10.49% ± 3.93% and 14.14 ± 2.85 (P < 0.05). The mean ROM values were 43.35 ± 7.55 before the operation, 34.83 ± 7.41 at 1-year postoperation (P < 0.05). The NDI scores decreased from 19.42 ± 4.12 to 7.37 ± 2.58, and the JOA scores increased from 8.87 ± 1.99 to 13.55 ± 1.72, representing significant improvement (P < 0.05). One patient had postoperative C5 nerve root palsy and completely recovered 1 month later. Neither collapse nor door closure in the open-door side occurred in any of the patients. Expansive open-door cervical laminoplasty with in situ reconstruction of extensor muscle insertion on the C2 spinous process combined with titanium miniplates internal fixation is a safe and effective surgical method

  8. Retinal Damage Induced by Internal Limiting Membrane Removal

    PubMed Central

    Gelman, Rachel; Stevenson, William; Prospero Ponce, Claudia; Agarwal, Daniel; Christoforidis, John Byron

    2015-01-01

    The internal limiting membrane (ILM), the basement membrane of the Müller cells, serves as the interface between the vitreous body and the retinal nerve fiber layer. It has a fundamental role in the development, structure, and function of the retina, although it also is a pathologic component in the various vitreoretinal disorders, most notably in macular holes. It was not until understanding of the evolution of idiopathic macular holes and the advent of idiopathic macular hole surgery that the idea of adjuvant ILM peeling in the treatment of tractional maculopathies was explored. Today intentional ILM peeling is a commonly applied surgical technique among vitreoretinal surgeons as it has been found to increase the rate of successful macular hole closure and improve surgical outcomes in other vitreoretinal diseases. Though ILM peeling has refined surgery for tractional maculopathies, like all surgical procedures it is not immune to perioperative risk. The essential role of the ILM to the integrity of the retina and risk of trauma to retinal tissue spurs suspicion with regard to its routine removal. Several authors have investigated the retinal damage induced by ILM peeling and these complications have been manifested across many different diagnostic studies. PMID:26425355

  9. Limitation of total hip arthroplasty of the acetabular roof by press-fit without screw fixation: discussion of a biomechanical study.

    PubMed

    Kanda, Akio; Kaneko, Kazuo; Obayashi, Osamu; Mogami, Atsuhiko; Iwase, Hideaki

    2013-05-01

    In total hip arthroplasty of the acetabular roof fixed by press-fit without screw fixation, there is little possibility for loosening to occur, because it is difficult for wear debris to enter between the cup and the acetabular roof, as screw holes are not present. However, stability is provided only by contact. In the case of acetabular dysplasia, it is not well understood whether sufficient initial fixation power is provided. We performed a torsion test and a lever-out test. In the torsion test, in the case of a normal hip joint, as the cup grew bigger, the fixation power tended to increase in strength. In the acetabular dysplasia model, with cups of each size, as the protrusion angle increased, the fixation power of the cup tended to become weak. When the protrusion angle approaches 15 degrees, we must use a cup that is 4 mm larger than the original cup to achieve the same initial fixation power. Furthermore, when the protrusion angle is 15 degrees in cups that are over 48 mm in size, we obtain fixation power that is theoretically adequate, but when small cups, for example, 46 mm in size are set with protrusion, the initial fixation power decreases significantly, and we cannot obtain a fixation power that is theoretically adequate. PMID:23412291

  10. 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.

    PubMed

    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. PMID:26528936

  11. Arterial Injury to the Profunda Femoris Artery following Internal Fixation of a Neck of Femur Fracture with a Compression Hip Screw

    PubMed Central

    2013-01-01

    We report the case of an 82-year-old woman who developed extensive proximal thigh swelling and persistent anaemia following internal fixation of an extracapsular neck of femur fracture with a dynamic hip screw (DHS). This was revealed to be a pseudoaneurysm of a branch of profunda femoris artery on angiography. Her case was further complicated by a concurrent pulmonary embolism (PE). She underwent endovascular coil embolisation of the pseudoaneurysm. An IVC filter was inserted and the patient was fully anticoagulated once it had been ensured that there was no active bleeding. In this case, we review the potential for anatomical variations in the blood supply to this region and discuss treatment options for a complicated patient. We recommend that a pseudoaneurysm should be part of a differential diagnosis for postoperative patients with anaemia refractory to blood transfusion so as not to miss this rare but potentially serious complication. PMID:24455367

  12. Surgical Fixation of Sternal Fractures: Preoperative Planning and a Safe Surgical Technique Using Locked Titanium Plates and Depth Limited Drilling

    PubMed Central

    Schulz-Drost, Stefan; Oppel, Pascal; Grupp, Sina; Schmitt, Sonja; Carbon, Roman Th.; Mauerer, Andreas; Hennig, Friedrich F.; Buder, Thomas

    2015-01-01

    Different ways to stabilize a sternal fracture are described in literature. Respecting different mechanisms of trauma such as the direct impact to the anterior chest wall or the flexion-compression injury of the trunk, there is a need to retain each sternal fragment in the correct position while neutralizing shearing forces to the sternum. Anterior sternal plating provides the best stability and is therefore increasingly used in most cases. However, many surgeons are reluctant to perform sternal osteosynthesis due to possible complications such as difficulties in preoperative planning, severe injuries to mediastinal organs, or failure of the performed method. This manuscript describes one possible safe way to stabilize different types of sternal fractures in a step by step guidance for anterior sternal plating using low profile locking titanium plates. Before surgical treatment, a detailed survey of the patient and a three dimensional reconstructed computed tomography is taken out to get detailed information of the fracture’s morphology. The surgical approach is usually a midline incision. Its position can be described by measuring the distance from upper sternal edge to the fracture and its length can be approximated by the summation of 60 mm for the basis incision, the thickness of presternal soft tissue and the greatest distance between the fragments in case of multiple fractures. Performing subperiosteal dissection along the sternum while reducing the fracture, using depth limited drilling, and fixing the plates prevents injuries to mediastinal organs and vessels. Transverse fractures and oblique fractures at the corpus sterni are plated longitudinally, whereas oblique fractures of manubrium, sternocostal separation and any longitudinally fracture needs to be stabilized by a transverse plate from rib to sternum to rib. Usually the high convenience of a patient is seen during follow up as well as a precise reconstruction of the sternal morphology. PMID

  13. Modification of the sinus tarsi approach for open reduction and plate fixation of intra-articular calcaneus fractures: the limits of proximal extension based upon the vascular anatomy of the lateral calcaneal artery.

    PubMed

    Femino, John E; Vaseenon, Tanawat; Levin, David A; Yian, Edward H

    2010-01-01

    The treatment of displaced calcaneal fractures remains controversial. Early surgical management to restore articular congruence and the structural function of the calcaneus is widely accepted as the best way to avoid the negative consequences of malunion. Concerns remain however regarding the best approach for reducing and maintaining reduction of these complex fractures, while minimizing the risk of surgical complications. The potential for serious wound complications is a major concern, particularly breakdown of the lateral calcaneal skin flap with the extensile lateral approach. Various approaches have been developed to try and balance the need for direct reduction of the articular surface while minimizing the potential for wound complications. Palmer originally described a laterally based approach through the sinus tarsi for direct visualization of the articular surface for reduction. He and others have found this approach to be useful and reasonably safe. At times, however, it may be necessary to extend the limits of a small incision over the sinus tarsi to treat adjacent fractures or to aid reduction in more complex fractures. In addition, a limited sinus tarsi incision without elevation of the lateral calcaneal skin flap does not allow for plate fixation, a notable advantage of the extensile lateral approach, particularly in gaining reduction of the body of the calcaneus. The authors have used an extended sinus tarsi approach to include placement of plate percutaneously beneath the lateral calcaneal skin flap through a sinus tarsi approach, and to treat adjacent fractures and soft tissue injuries. A clinical series of 13 patients (including 7 chronic smokers and 1 with diabetes and vascular disease) with closed displaced intra-articular calcaneal fractures (Sanders types II and III) were treated by open reduction and internal fixation via this approach. Adjacent fractures were treated through the same incision. Two patients developed wound complications. No

  14. The International Baccalaureate and "Growth Scepticism": A "Social Limits" Framework

    ERIC Educational Resources Information Center

    Bunnell, Tristan

    2011-01-01

    The number of schools offering the programmes of the International Baccalaureate (IB) hit 3000 in July 2010. Since 2004 the IB has aimed for further growth within a "wider access" and "greater impact" paradigm. A "further" 7000 schools are expected to be involved by 2020. However, there is now considerable concern about growth, especially within…

  15. Latarjet Fixation

    PubMed Central

    Alvi, Hasham M.; Monroe, Emily J.; Muriuki, Muturi; Verma, Rajat N.; Marra, Guido; Saltzman, Matthew D.

    2016-01-01

    Background: Attritional bone loss in patients with recurrent anterior instability has successfully been treated with a bone block procedure such as the Latarjet. It has not been previously demonstrated whether cortical or cancellous screws are superior when used for this procedure. Purpose: To assess the strength of stainless steel cortical screws versus stainless steel cannulated cancellous screws in the Latarjet procedure. Study Design: Controlled laboratory study. Methods: Ten fresh-frozen matched-pair shoulder specimens were randomized into 2 separate fixation groups: (1) 3.5-mm stainless steel cortical screws and (2) 4.0-mm stainless steel partially threaded cannulated cancellous screws. Shoulder specimens were dissected free of all soft tissue and a 25% glenoid defect was created. The coracoid process was osteomized, placed at the site of the glenoid defect, and fixed in place with 2 parallel screws. Results: All 10 specimens failed by screw cutout. Nine of 10 specimens failed by progressive displacement with an increased number of cycles. One specimen in the 4.0-mm screw group failed by catastrophic failure on initiation of the testing protocol. The 3.5-mm screws had a mean of 274 cycles (SD, ±171 cycles; range, 10-443 cycles) to failure. The 4.0-mm screws had a mean of 135 cycles (SD, ±141 cycles; range, 0-284 cycles) to failure. There was no statistically significant difference between the 2 types of screws for cycles required to cause failure (P = .144). Conclusion: There was no statistically significant difference in energy or cycles to failure when comparing the stainless steel cortical screws versus partially threaded cannulated cancellous screws. Clinical Relevance: Latarjet may be performed using cortical or cancellous screws without a clear advantage of either option. PMID:27158630

  16. 14 CFR 121.513 - Flight time limitations: Overseas and international operations: airplanes.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Flight time limitations: Overseas and...: CERTIFICATION AND OPERATIONS OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Flight Time Limitations: Supplemental Operations § 121.513 Flight time limitations: Overseas and international...

  17. 14 CFR 121.513 - Flight time limitations: Overseas and international operations: airplanes.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Flight time limitations: Overseas and...: CERTIFICATION AND OPERATIONS OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Flight Time Limitations: Supplemental Operations § 121.513 Flight time limitations: Overseas and international...

  18. 14 CFR 121.513 - Flight time limitations: Overseas and international operations: airplanes.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Flight time limitations: Overseas and...: CERTIFICATION AND OPERATIONS OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Flight Time Limitations: Supplemental Operations § 121.513 Flight time limitations: Overseas and international...

  19. Orthopedic prosthesis fixation.

    PubMed

    Park, J B

    1992-01-01

    The fixation of orthopedic implants has been one of the most difficult and challenging problems. The fixation can be achieved via: (a) direct mechanical fixation using screws, pins, wires, etc.; (b) passive or interference mechanical fixation where the implants are allowed to move or merely positioned onto the tissue surfaces; (c) bone cement fixation which is actually a grouting material; (d) biological fixation by allowing tissues to grow into the interstices of pores or textured surfaces of implants; (e) direct chemical bonding between implant and tissues; or (f) any combination of the above techniques. This article is concerned with various fixation techniques including the potential use of electrical, pulsed electromagnetic field, chemical stimulation using calcium phosphates for the enhancement of tissue ingrowth, direct bonding with bone by glass-ceramics and resorbable particle impregnated bone cement to take advantages of both the immediate fixation offered by the bone cement and long term fixation due to tissue ingrowth. PMID:1449228

  20. A Biomechanical Comparison of Three 1.5-mm Plate and Screw Configurations and a Single 2.0-mm Plate for Internal Fixation of a Mandibular Condylar Fracture

    PubMed Central

    Aquilina, Peter; Parr, William C.H.; Chamoli, Uphar; Wroe, Stephen; Clausen, Philip

    2014-01-01

    The most stable pattern of internal fixation for mandibular condyle fractures is an area of ongoing discussion. This study investigates the stability of three patterns of plate fixation using readily available, commercially pure titanium implants. Finite element models of a simulated mandibular condyle fracture were constructed. The completed models were heterogeneous in bone material properties, contained approximately 1.2 million elements and incorporated simulated jaw adducting musculature. Models were run assuming linear elasticity and isotropic material properties for bone. No human subjects were involved in this investigation. The stability of the simulated condylar fracture reduced with the different implant configurations, and the von Mises stresses of a 1.5-mm X-shaped plate, a 1.5-mm rectangular plate, and a 1.5-mm square plate (all Synthes (Synthes GmbH, Zuchwil, Switzerland) were compared. The 1.5-mm X plate was the most stable of the three 1.5-mm profile plate configurations examined and had comparable mechanical performance to a single 2.0-mm straight four-hole plate. This study does not support the use of rectangular or square plate patterns in the open reduction and internal fixation of mandibular condyle fractures. It does provide some support for the use of a 1.5-mm X plate to reduce condylar fractures in selected clinical cases. PMID:25136411

  1. A hinged external fixator for complex elbow dislocations: A multicenter prospective cohort study

    PubMed Central

    2011-01-01

    Background Elbow dislocations can be classified as simple or complex. Simple dislocations are characterized by the absence of fractures, while complex dislocations are associated with fractures of the radial head, olecranon, or coronoid process. The majority of patients with these complex dislocations are treated with open reduction and internal fixation (ORIF), or arthroplasty in case of a non-reconstructable radial head fracture. If the elbow joint remains unstable after fracture fixation, a hinged elbow fixator can be applied. The fixator provides stability to the elbow joint, and allows for early mobilization. The latter may be important for preventing stiffness of the joint. The aim of this study is to determine the effect of early mobilization with a hinged external elbow fixator on clinical outcome in patients with complex elbow dislocations with residual instability following fracture fixation. Methods/Design The design of the study will be a multicenter prospective cohort study of 30 patients who have sustained a complex elbow dislocation and are treated with a hinged elbow fixator following fracture fixation because of residual instability. Early active motion exercises within the limits of pain will be started immediately after surgery under supervision of a physical therapist. Outcome will be evaluated at regular intervals over the subsequent 12 months. The primary outcome is the Quick Disabilities of the Arm, Shoulder, and Hand score. The secondary outcome measures are the Mayo Elbow Performance Index, Oxford Elbow Score, pain level at both sides, range of motion of the elbow joint at both sides, radiographic healing of the fractures and formation of periarticular ossifications, rate of secondary interventions and complications, and health-related quality of life (Short-Form 36). Discussion The outcome of this study will yield quantitative data on the functional outcome in patients with a complex elbow dislocation and who are treated with ORIF and

  2. 78 FR 57674 - Order Limiting Operations at Newark Liberty International Airport

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-19

    ... waivers to the usage requirement except under the most unusual circumstances. \\1\\ 78 FR 28280, 28281 (May... Federal Aviation Administration Order Limiting Operations at Newark Liberty International Airport AGENCY... authorizations (slots) at Newark Liberty International Airport (EWR) due to construction at the airport...

  3. Coordination of International Exchange and Training Programs--the Opportunities and Limitations

    ERIC Educational Resources Information Center

    Hovey, J. Allan, Jr.

    1978-01-01

    Limitations of and opportunities for interagency coordination and data sharing among Federal international exchange and training programs are discussed in this article, based on a General Accounting Office (GAO) study. Included are the GAO's recommendations to the International Communication Agency (ICA). (JMD)

  4. 14 CFR 121.513 - Flight time limitations: Overseas and international operations: airplanes.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Flight time limitations: Overseas and international operations: airplanes. 121.513 Section 121.513 Aeronautics and Space FEDERAL AVIATION...: airplanes. In place of the flight time limitations in §§ 121.503 through 121.511, a certificate...

  5. Bohler’s angle’s role in assessing the injury severity and functional outcome of internal fixation for displaced intra-articular calcaneal fractures: a retrospective study

    PubMed Central

    2013-01-01

    Background Controversy exits over the role of Böhler’s angle in assessing the injury severity of displaced intra-articular calcaneal fractures and predicting the functional outcome following internal fixation. This study aims to investigate whether a correlation exists between Böhler’s angle and the injury severity of displaced calcaneal fractures, and between surgical improvement of Böhler’s angle and functional outcome. Methods Patients treated operatively for unilateral closed displaced intra-articular calcaneal fractures from January 1, 2004 to March 31, 2008 were identified. The Böhler’s angles of both calcaneus were measured, and the measurement of the uninjured foot was used as its normal control. The difference in the value of Böhler’s angle measured preoperatively or postoperatively between the angle of the injured foot and that of the contralateral calcaneus were calculated, respectively. The change in Böhler’s angle by ratio was calculated by dividing the difference value of Böhler’s angle between bilateral calcaneus by its normal control. The injury severity was assessed according to Sanders classification. The functional outcomes were assessed using American Orthopaedic Foot & Ankle Society hindfoot scores. Results 274 patients were included into the study with a mean follow-up duration of 71 months. According to Sanders classification, the fracture pattern included 105 type II, 121 type III and 48 type IV fractures. According to American Orthopaedic Foot & Ankle Society hindfoot scoring system, the excellent, good, fair and poor results were achieved in 104, 132, 27, and 11 patients, respectively. The preoperative Böhler’s angle, difference value of Böhler’s angle between bilateral calcaneus, and change in Böhler’s angle by ratio each has a significant correlation with Sanders classification (rs=−0.178, P=0.003; rs=−0.174, P=0.004; rs=−0.172, P=0.005, respectively), however, is not correlated with functional outcome

  6. Global solution for a kinetic chemotaxis model with internal dynamics and its fast adaptation limit

    NASA Astrophysics Data System (ADS)

    Liao, Jie

    2015-12-01

    A nonlinear kinetic chemotaxis model with internal dynamics incorporating signal transduction and adaptation is considered. This paper is concerned with: (i) the global solution for this model, and, (ii) its fast adaptation limit to Othmer-Dunbar-Alt type model. This limit gives some insight to the molecular origin of the chemotaxis behaviour. First, by using the Schauder fixed point theorem, the global existence of weak solution is proved based on detailed a priori estimates, under quite general assumptions. However, the Schauder theorem does not provide uniqueness, so additional analysis is required to be developed for uniqueness. Next, the fast adaptation limit of this model is derived by extracting a weak convergence subsequence in measure space. For this limit, the first difficulty is to show the concentration effect on the internal state. Another difficulty is the strong compactness argument on the chemical potential, which is essential for passing the nonlinear kinetic equation to the weak limit.

  7. Core-halo limit and internal dynamics of high intensity beams

    SciTech Connect

    Nghiem, P. A. P.; Valette, M.; Chauvin, N.; Pichoff, N.; Uriot, D.

    2015-08-15

    The dynamics of high-intensity beams largely depends on their internal space charge forces. These forces are responsible of non-linear coupling, emittance growth, and halo generation. They contribute to shape the beam density profile. As a consequence, an analysis of this profile can be a precious indicator capable of revealing the internal dynamics of the beam. This paper recalls the precise core-halo limit determination proposed earlier, then studies its behavior through a wide range of beam profiles, and finally shows its relevance as an indicator of the limit separating the two space charge field regimes of the core and the halo.

  8. Kennedy Space Center Fixation Tube (KFT)

    NASA Technical Reports Server (NTRS)

    Richards, Stephanie E.; Levine, Howard G.; Romero, Vergel

    2016-01-01

    Experiments performed on the International Space Station (ISS) frequently require the experimental organisms to be preserved until they can be returned to earth for analysis in the appropriate laboratory facility. The Kennedy Fixation Tube (KFT) was developed to allow astronauts to apply fixative, chemical compounds that are often toxic, to biological samples without the use of a glovebox while maintaining three levels of containment (Fig. 1). KFTs have been used over 200 times on-orbit with no leaks of chemical fixative. The KFT is composed of the following elements: a polycarbonate main tube where the fixative is loaded preflight, the sample tube where the plant or other biological specimens is placed during operations, the expansion plug, actuator, and base plug that provides fixative containment (Fig. 2). The main tube is pre-filled with 25 mL of fixative solution prior to flight. When actuated, the specimen contained within the sample tube is immersed with approximately 22 mL (+/- 2 mL) of the fixative solution. The KFT has been demonstrated to maintain its containment at ambient temperatures, 4degC refrigeration and -100 C freezing conditions.

  9. 14 CFR 121.513 - Flight time limitations: Overseas and international operations: airplanes.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Flight time limitations: Overseas and international operations: airplanes. 121.513 Section 121.513 Aeronautics and Space FEDERAL AVIATION...: CERTIFICATION AND OPERATIONS OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Flight...

  10. Cost of external fixation vs external fixation then nailing in bone infection

    PubMed Central

    Emara, Khaled Mohamed; Diab, Ramy Ahmed; Ghafar, Khaled Abd EL

    2015-01-01

    AIM: To study the cost benefit of external fixation vs external fixation then nailing in treatment of bone infection by segment transfer. METHODS: Out of 71 patients with infected nonunion tibia treated between 2003 and 2006, 50 patients fitted the inclusion criteria (26 patients were treated by external fixation only, and 24 patients were treated by external fixation early removal after segment transfer and replacement by internal fixation). Cost of inpatient treatment, total cost of inpatient and outpatient treatment till full healing, and the weeks of absence from school or work were calculated and compared between both groups. RESULTS: The cost of hospital stay and surgery in the group of external fixation only was 22.6 ± 3.3 while the cost of hospital stay and surgery in the group of early external fixation removal and replacement by intramedullary nail was 26.0 ± 3.2. The difference was statistically significant regarding the cost of hospital stay and surgery in favor of the group of external fixation only. The total cost of medical care (surgery, hospital stay, treatment outside the hospital including medications, dressing, physical therapy, outpatient laboratory work, etc.) in group of external fixation only was 63.3 ± 15.1, and total absence from work was 38.6 ± 6.6 wk. While the group of early removal of external fixation and replacement by IM nail, total cost of medical care was 38.3 ± 6.4 and total absence from work or school was 22.7 ± 4.1. The difference was statistically significant regarding the total cost and absence from work in favor of the group of early removal and replacement by IM nail. CONCLUSION: Early removal of external fixation and replacement by intramedullary nail in treatment of infected nonunion showed more cost effectiveness. Orthopaedic society needs to show the cost effectiveness of different procedures to the community, insurance, and health authorities. PMID:25621219

  11. Dose limits to the lens of the eye: International Basic Safety Standards and related guidance.

    PubMed

    Boal, T J; Pinak, M

    2015-06-01

    The International Atomic Energy Agency (IAEA) safety requirements: 'General Safety Requirements Part 3--Radiation protection and safety of radiation sources: International Basic Safety Standards' (BSS) was approved by the IAEA Board of Governors at its meeting in September 2011, and was issued as General Safety Requirements Part 3 in July 2014. The equivalent dose limit for the lens of the eye for occupational exposure in planned exposure situations was reduced from 150 mSv year(-1) to 20 mSv year(-1), averaged over defined periods of 5 years, with no annual dose in a single year exceeding 50 mSv. This reduction in the dose limit for the lens of the eye followed the recommendation of the International Commission on Radiological Protection in its statement on tissue reactions of 21 April 2011. IAEA has developed guidance on the implications of the new dose limit for the lens of the eye. This paper summarises the process that led to the inclusion of the new dose limit for the lens of the eye in the BSS, and the implications of the new dose limit. PMID:25816264

  12. Fixation of distal radius fractures in adults: a review.

    PubMed

    Obert, L; Rey, P-B; Uhring, J; Gasse, N; Rochet, S; Lepage, D; Serre, A; Garbuio, P

    2013-04-01

    In patients for whom function is a priority, anatomic reduction and stable fixation are prerequisites for good outcomes. Several therapeutic options exist, including orthopedic treatment and internal fixation with pins (intra- and extrafocal), external fixation which may or may not bridge the wrist, and different internal fixation techniques with dorsal or palmar plates using or not, locking screws. Arthroscopy may be necessary in case of articular fracture. In the presence of significant metaphyseal bone defects, filling of the comminution with phosphocalcic cements provides better graft stability. The level of evidence is too low to allow recommending one type of fixation for one type of fracture; and different fixation options to achieve stable reduction exist, each with its own specific complications. With the new generations of palmar plate, secondary displacement is becoming a thing of the past. PMID:23518070

  13. Benthic N2 fixation in coral reefs and the potential effects of human-induced environmental change.

    PubMed

    Cardini, Ulisse; Bednarz, Vanessa N; Foster, Rachel A; Wild, Christian

    2014-05-01

    Tropical coral reefs are among the most productive and diverse ecosystems, despite being surrounded by ocean waters where nutrients are in short supply. Benthic dinitrogen (N2) fixation is a significant internal source of "new" nitrogen (N) in reef ecosystems, but related information appears to be sparse. Here, we review the current state (and gaps) of knowledge on N2 fixation associated with coral reef organisms and their ecosystems. By summarizing the existing literature, we show that benthic N2 fixation is an omnipresent process in tropical reef environments. Highest N2 fixation rates are detected in reef-associated cyanobacterial mats and sea grass meadows, clearly showing the significance of these functional groups, if present, to the input of new N in reef ecosystems. Nonetheless, key benthic organisms such as hard corals also importantly contribute to benthic N2 fixation in the reef. Given the usually high coral coverage of healthy reef systems, these results indicate that benthic symbiotic associations may be more important than previously thought. In fact, mutualisms between carbon (C) and N2 fixers have likely evolved that may enable reef communities to mitigate N limitation. We then explore the potential effects of the increasing human interferences on the process of benthic reef N2 fixation via changes in diazotrophic populations, enzymatic activities, or availability of benthic substrates favorable to these microorganisms. Current knowledge indicates positive effects of ocean acidification, warming, and deoxygenation and negative effects of increased ultraviolet radiation on the amount of N fixed in coral reefs. Eutrophication may either boost or suppress N2 fixation, depending on the nutrient becoming limiting. As N2 fixation appears to play a fundamental role in nutrient-limited reef ecosystems, these assumptions need to be expanded and confirmed by future research efforts addressing the knowledge gaps identified in this review. PMID:24967086

  14. Benthic N2 fixation in coral reefs and the potential effects of human-induced environmental change

    PubMed Central

    Cardini, Ulisse; Bednarz, Vanessa N; Foster, Rachel A; Wild, Christian

    2014-01-01

    Tropical coral reefs are among the most productive and diverse ecosystems, despite being surrounded by ocean waters where nutrients are in short supply. Benthic dinitrogen (N2) fixation is a significant internal source of “new” nitrogen (N) in reef ecosystems, but related information appears to be sparse. Here, we review the current state (and gaps) of knowledge on N2 fixation associated with coral reef organisms and their ecosystems. By summarizing the existing literature, we show that benthic N2 fixation is an omnipresent process in tropical reef environments. Highest N2 fixation rates are detected in reef-associated cyanobacterial mats and sea grass meadows, clearly showing the significance of these functional groups, if present, to the input of new N in reef ecosystems. Nonetheless, key benthic organisms such as hard corals also importantly contribute to benthic N2 fixation in the reef. Given the usually high coral coverage of healthy reef systems, these results indicate that benthic symbiotic associations may be more important than previously thought. In fact, mutualisms between carbon (C) and N2 fixers have likely evolved that may enable reef communities to mitigate N limitation. We then explore the potential effects of the increasing human interferences on the process of benthic reef N2 fixation via changes in diazotrophic populations, enzymatic activities, or availability of benthic substrates favorable to these microorganisms. Current knowledge indicates positive effects of ocean acidification, warming, and deoxygenation and negative effects of increased ultraviolet radiation on the amount of N fixed in coral reefs. Eutrophication may either boost or suppress N2 fixation, depending on the nutrient becoming limiting. As N2 fixation appears to play a fundamental role in nutrient-limited reef ecosystems, these assumptions need to be expanded and confirmed by future research efforts addressing the knowledge gaps identified in this review. PMID:24967086

  15. Fixation: A Bibliography.

    ERIC Educational Resources Information Center

    Pedrini, D. T.; Pedrini, Bonnie C.

    Fixation and regression were considered complementary by Freud. You tend to regress to a point of fixation. They are both opposed to progression. In the general area, Anna Freud has written (The Ego and the Mechanisms of Defence. London: Hogarth and the Psycho-Analytic Institute, 1937), Sears has evaluated (Survey of Objective Studies of…

  16. Open reduction and internal fixation versus casting for highly comminuted and intra-articular fractures of the distal radius (ORCHID): protocol for a randomized clinical multi-center trial

    PubMed Central

    2011-01-01

    Background Fractures of the distal radius represent the most common fracture in elderly patients, and often indicate the onset of symptomatic osteoporosis. A variety of treatment options is available, including closed reduction and plaster casting, K-wire-stabilization, external fixation and open reduction and internal fixation (ORIF) with volar locked plating. The latter is widely promoted by clinicians and hardware manufacturers. Closed reduction and cast stabilization for six weeks is a simple, convenient, and ubiquitously available intervention. In contrast, ORIF requires hospitalization, but allows for functional rehabilitation. Given the lack of randomized controlled trials, it remains unclear whether ORIF leads to better functional outcomes one year after injury than closed reduction and casting. Methods/Design ORCHID (Open reduction and internal fixation versus casting for highly comminuted intra-articular fractures of the distal radius) is a pragmatic, randomized, multi-center, clinical trial with two parallel treatment arms. It is planned to include 504 patients in 15 participating centers throughout Germany over a three-year period. Patients are allocated by a central web-based randomization tool. The primary objective is to determine differences in the Short Form 36 (SF-36) Physical Component Score (PCS) between volar locked plating and closed reduction and casting of intraarticular, comminuted distal radius fractures in patients > 65 years of age one year after the fracture. Secondary outcomes include differences in other SF-36 dimensions, the EuroQol-5D questionnaire, the Disability of the Arm, Shoulder, and Hand (DASH) instrument. Also, the range of motion in the affected wrist, activities of daily living, complications (including secondary ORIF and revision surgery), as well as serious adverse events will be assessed. Data obtained during the trial will be used for later health-economic evaluations. The trial architecture involves a central

  17. Intermaxillary fixation screws versus Erich arch bars in mandibular fractures: A comparative study and review of literature

    PubMed Central

    Qureshi, Ahtesham Ahmad; Reddy, Umesh K.; Warad, N. M.; Badal, Sheeraz; Jamadar, Amjad Ali; Qurishi, Nilofar

    2016-01-01

    Objective: Various techniques have been employed from time to time to achieve maxillomamdibular fixation. Although arch bars provide an effective and versatile means of maxillomandibular fixation, their use is not without shortcomings. However the introduction of intermaxillary fixation screws (IMF) has eliminated many of these issues of arch bars. The aim of the present study was to compare the advantages and disadvantages of intermaxillary fixation screws over the Erich arch bars in mandibular fractures. Materials and Methods: Sixty dentulous patients who reported to Department of Oral and Maxillofacial Surgery, Al-Ameen Dental College and Hospital, Bijapur with mandibular fractures and required intermaxillary fixation as a part of treatment plan followd by open reduction and internal fixation under GA were selected and randomly divided into 2 groups of 30 patients each that is Group A and Group B. Group A included patients who received intermaxillary fixation with Erich arch bars. Group B includes patients who received intermaxillary fixation with IMF Screws. The parameters compared in both the groups included, surgical time taken, gloves perforation, post-operative occlusion, IMF stability, oral hygiene, patient acceptance and comfort and non-vitality characteristics. Results: The average surgical time taken and gloves perforations were more in Group A,the patient acceptance and oral hygiene was better in Group B, there was not much statistically significant difference in postoperative occlusion and IMF stability in both groups. Accidental root perforation was the only limitation of IMF screws. Conclusion: Intermaxillary fixation with IMF screws is more efficacious compared to Erich arch bars in the treatment of mandibular fractures.

  18. Simulating the effect of SFCL on limiting the internal fault of synchronous machine

    NASA Astrophysics Data System (ADS)

    Kheirizad, I.; Varahram, M. H.; Jahed-Motlagh, M. R.; Rahnema, M.; Mohammadi, A.

    2008-02-01

    In this paper, we have modelled a synchronous generator with internal one phase to ground fault and then the performance of this machine with internal one phase to ground fault have been analyzed. The results show that if the faults occur in vicinity of machine's terminal, then we would have serious damages. To protect the machine from this kind of faults we have suggested integrating a SFCL (superconducting fault current limiter) into the machine's model. The results show that the fault currents in this case will reduce considerably without influencing the normal operation of the machine.

  19. Periprosthetic fracture fixation in osteoporotic bone.

    PubMed

    Lenz, Mark; Lehmann, Wolfgang; Wähnert, Dirk

    2016-06-01

    Fixation techniques of periprosthetic fractures are far from ideal although the number of this entity is rising. The presence of an intramedullary implant generates its own fracture characteristics since stiffness is altered along the bone shaft and certain implant combinations affect load resistance of the bone. Influencing factors are cement fixation of the implant, intramedullary locking and extramedullary or intramedullary localization of the implant and the cortical thickness of the surrounding bone. Cerclage wires are ideally suited to fix radially displaced fragments around an intramedullary implant but they are susceptible to axial and torsional load. Screws should be added if these forces have to be neutralized. Stability of the screw fixation itself can be enhanced by embracement configuration around the intramedullary implant. Poor bone stock quality, often being present in metaphyseal areas limits screw fixation. Cement augmentation is an attractive option in this field to enhance screw purchase. PMID:27338227

  20. Histologic and Histometric Analysis of Bone Repair at the Site of Mandibular Body Osteotomy and at the Bone-Screw Interface After Using a Biodegradable 2.0-mm Internal Fixation System.

    PubMed

    Sverzut, Cassio Edvard; de Matos, Fernando Pando; Trivellato, Alexandre Elias; Kato, Rogerio Bentes; Sverzut, Alexander Tadeu; Taba Junior, Mario; de Rezende Duek, Eliana Aparecida; de Oliveira, Paulo Tambasco

    2015-06-01

    The aim of the study was to evaluate histologically and histometrically the bone repair at the mandibular body osteotomy and at the bone-screw interface after using a biodegradable 2.0-mm internal fixation system. Six dogs were subjected to an osteotomy in the mandibular body, which was stabilized by applying a fixation device manufactured with poly-L-DL-lactic acid (70:30). The dogs were euthanized at 2 and 18 weeks. Each screw was sectioned along its long axis, and the osteotomy sites were divided into 3 parts: the upper part was labeled the tension third (TT); the lower part, compression third (CT); and the part between the TT and CT, intermediary third (IT). Histologic analysis showed areas of direct contact between the screw surface and the parent lamellar bone at 2 weeks. At 18 weeks, 3 microscopically distinct layers at the bone-screw interface were noted. At the osteotomy sites, union between the bone fragments was observed at 18 weeks. Statistically significant differences in the newly formed bone among TT, IT, and CT (P = 0.019) were observed. In conclusion, the biomechanical environment created by the biodegradable IF system used in this study facilitated bone repair at the osteotomy site. PMID:26080160

  1. Inverted internal limiting membrane flap technique for very large macular hole

    PubMed Central

    Khodani, Mitali; Bansal, Pooja; Narayanan, Raja; Chhablani, Jay

    2016-01-01

    AIM To assess the anatomical and visual outcome of idiopathic macular holes greater than 1000 µm using the inverted internal limiting membrane flap technique. METHODS This retrospective case series included 5 eyes of 5 patients with idiopathic macular hole with base diameter greater than 1000 µm who underwent inverted internal limiting membrane flap technique along with standard 23G pars plans vitrectomy with posterior hyaloid detachment and fluid gas exchange with 12%-14% perfluoropropane (C3F8). Preoperative and postoperative visual acuity and spectral domain optical coherence tomography images were evaluated. The main outcome measures were visual outcome and macular hole closure. RESULTS Mean age was 63.2±8.4y with all 5 subjects being females. Mean duration of symptoms was 11±14mo with a mean postoperative follow up of 13.2±13mo. The mean base diameter of the macular holes was 1420±84.8 µm (1280-1480 µm). Type 1 closure was achieved in four out of five patients, while one patient had type 2 closure using the inverted internal limiting membrane (ILM) flap technique. Median baseline BCVA was 0.79 logMAR (Snellen's equivalent 20/120) and median final BCVA 0.6 logMAR (Snellen's equivalent 20/80) with mean visual improvement of approximately three lines improvement. No complications related to surgical procedure were noted. CONCLUSION The inverted internal limiting membrane flap technique may be promising for very large macular holes with high rate of macular closure and good visual outcome. PMID:27588280

  2. The cause of 2S Diapason screw breakage after internal lumbar fixation: studies of the mechanical and material properties of the implant.

    PubMed

    Kolasa, P; Grabarczyk, J; Depczyk, T

    2002-08-30

    In the years 1994-99, unstable fractures of the lumbar spine were surgically treated with interbody fixation in the Department of Neurosurgery at the Nicholas Copernicus Voivodeship Specialized Hospital in Łódź, using stabilizers manufactured by various companies. Complications in the form of stabilizer breakage were observed in 1 case out of 22. The aim of the present study was to ascertain the reason why the Stryker 2S Diapason screws broke. Tests performed to measure the material and mechanical properties of the implant did not show any signs of material fatigue, nor were any material defects discovered. However, a scanning microscope investigation confirmed the hypothesis that the material had crumbled due to overload. This discovery led to the decision that screws would be mounted in the bodies of the vertebrae in a manner decreasing implant load. PMID:17679886

  3. Rapid internal dose magnitude estimation in emergency situations using annual limits on intake (ALI) comparisons.

    PubMed

    Sugarman, Stephen L; Toohey, Richard; Goans, Ronald; Christensen, Doran; Wiley, Albert

    2010-06-01

    It is crucial to integrate health physics into the medical management of radiation illness or injury. The key to early medical management is not necessarily radiation dose calculation and assignment, but radiation dose magnitude estimation. The magnitude of the dose can be used to predict potential biological consequences and the corresponding need for medical intervention. It is, therefore, imperative that physicians and health physicists have the necessary tools to help guide this decision making process. All internal radiation doses should be assigned using proper dosimetry techniques, but the formal internal dosimetry process often takes time that may delay treatment, thus reducing the efficacy of some medical countermeasures. Magnitudes of inhalation or ingestion intakes or intakes associated with contaminated wounds can be estimated by applying simple rules of thumb to sample results or direct measurements and comparing the outcome to known limits for a projection of dose magnitude. Although a United States regulatory unit, the annual limit on intake (ALI) is based on committed dose, and can therefore be used as a comparison point. For example, internal dose magnitudes associated with contaminated wounds can be estimated by comparing a direct wound measurement taken soon after the injury to the product of the ingestion ALI and the associated f1 value (the fractional uptake from the small intestine to the blood). International Commission on Radiation Protection Publication 96, as well as other resources, recommends treatment based on ALI determination. Often, treatment decisions have to be made with limited information. However, one can still perform dose magnitude estimations in order to help effectively guide the need for medical treatment by properly assessing the situation and appropriately applying basic rules of thumb. PMID:20445387

  4. Photographic fixative poisoning

    MedlinePlus

    Photographic developer poisoning; Hydroquinone poisoning; Quinone poisoning; Sulfite poisoning ... Hydroquinones Quinones Sodium thiosulfate Sodium sulfite/bisulfite Boric acid Photographic fixative can also break down (decompose) to form sulfur dioxide gas.

  5. Methanotrophy Induces Nitrogen Fixation in Boreal Mosses

    NASA Astrophysics Data System (ADS)

    Tiirola, M. A.

    2014-12-01

    Many methanotrophic bacterial groups fix nitrogen in laboratory conditions. Furthermore, nitrogen (N) is a limiting nutrient in many environments where methane concentrations are highest. Despite these facts, methane-induced N fixation has previously been overlooked, possibly due to methodological problems. To study the possible link between methanotrophy and diazotrophy in terrestrial and aquatic habitats, we measured the co-occurrence of these two processes in boreal forest, peatland and stream mosses using a stable isotope labeling approach (15 N2 and 13 CH4 double labeling) and sequencing of the nifH gene marker. N fixation associated with forest mosses was dependent on the annual N deposition, whereas methane stimulate N fixation neither in high (>3 kg N ha -1 yr -1) nor low deposition areas, which was in accordance with the nifH gene sequencing showing that forest mosses (Pleurozium schreberi and Hylocomium splendens ) carried mainly cyanobacterial N fixers. On the other extreme, in stream mosses (Fontinalis sp.) methane was actively oxidized throughout the year, whereas N fixation showed seasonal fluctuation. The co-occurrence of the two processes in single cell level was proven by co-localizing both N and methane-carbon fixation with the secondary ion mass spectrometry (SIMS) approach. Methanotrophy and diazotrophy was also studied in peatlands of different primary successional stages in the land-uplift coast of Bothnian Bay, in the Siikajoki chronosequence, where N accumulation rates in peat profiles indicate significant N fixation. Based on experimental evidence it was counted that methane-induced N fixation explained over one-third of the new N input in the younger peatland successional stages, where the highest N fixation rates and highest methane oxidation activities co-occurred in the water-submerged Sphagnum moss vegetation. The linkage between methanotrophic carbon cycling and N fixation may therefore constitute an important mechanism in the rapid

  6. An Isolated Displaced Fracture of the Coracoid Process Treated with Open reduction and internal fixation - A Case Report and Review of Literature

    PubMed Central

    Archik, Shreedhar; Nanda, Saurav Narayan; Tripathi, Sanjay; Choudhari, Ashlesh; Rajadhyaksha, Harshada

    2016-01-01

    Introduction: Isolated coracoid fractures are rare and few scattered cases are reported in literature. Coracoid fractures can be missed and the treatment for coracoid process fractures is still controversial. The case presented here is of an isolated coracoid process fracture which was treated surgically. Case Report: A 15-years old male presented after 4 days of injury complaining of persistent pain in the right shoulder following a jerk during bowling. Physical examination revealed tenderness in the left shoulder. There was pain on abduction and external rotation. The neurovascular examination was normal. Osseous avulsion of the distal tip of the coracoid process was confirmed by CT and MRI. The short head of the biceps and coracobrachialis was attached to the avulsed tip, while the pectoralis minor was attached to the coracoid base. The case was managed by open reduction and fixation with a 3.5mm cannulated screw and washer. Conclusion: Isolated coracoid fracture is a rare entity causing impairment of upper limb movement. It can be diagnosed more accurately by MRI scan and CT scan. In case of young highly demanding individuals like athletes surgical management may be a better option as compared to conservative treatment to achieve early use of the extremity, good radiological union and clinical function. PMID:27299123

  7. Limiter

    DOEpatents

    Cohen, S.A.; Hosea, J.C.; Timberlake, J.R.

    1984-10-19

    A limiter with a specially contoured front face is provided. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution. This limiter shape accommodates the various power scrape-off distances lambda p, which depend on the parallel velocity, V/sub parallel/, of the impacting particles.

  8. Overcoming Organizational Fixation: Creating and Sustaining an Innovation Culture

    ERIC Educational Resources Information Center

    Stempfle, Joachim

    2011-01-01

    Fixation on established paradigms and practices can severely limit the capability of organizations to change, thereby jeopardizing the ability of organizations to keep up with changes in their environment and new technological developments. Overcoming organizational fixation is therefore a requirement for any organization that strives to achieve…

  9. Assessment of the influence of Laser phototherapy on the bone repair process of complete fractures in tibiae of rabbits stabilized with semi-rigid internal fixation treated with or without MTA graft: a histological study

    NASA Astrophysics Data System (ADS)

    Soares, Luiz G. P.; Silva, Aline C. P.; Silva, Anna Paula L. T.; Neves, Bruno Luiz R. C.; Santos, Nicole R. S.; dos Santos, Jean N.; Pinheiro, Antonio L. B.

    2016-03-01

    Beside biomaterials, Laser phototherapy has shown positive effects as auxiliary therapy in bone repair process, especially when involving large bone losses. The aim of this histological study was to evaluate, by light microscopy, the influence of laser phototherapy on the repair of complete tibial fractures in rabbits treated or not with semi-rigid internal fixation and Mineral Trioxide Aggregate - MTA graft. Twelve Rabbits were randomly divided into four groups with three animals each. After general anesthesia, complete fractures were created in one tibia with a carborundum disk. All animals (groups I-IV) had the fracture stabilized with semi-rigid fixation (wire osteosynthesis - WO). Group I was routinely fixed with WO; groups II and IV fracture was filled by blood clot and MTA implant. In Groups III and IV fracture was filled by blood clot and further irradiated with laser (λ780 nm, 70 mW, CW, Φ = 0.04 cm2, 20.4 J/cm2, per session, t = 300s, 142.8 J/cm2 per treatment). The phototherapy protocol was applied immediately after the surgery and repeated each 48 hours during 15 days. Animal death occurred on the 30th postoperative day. After removal of the specimens, the samples were routinely processed, stained with HE and evaluated by light microscopy. Histologically, the group treated with MTA graft and irradiated with laser showed the fracture filled by a more organized and mature trabecular bone, when compared with all other groups. From the results of the present study, it may be concluded that the association of Laser phototherapy + MTA graft in fractures treated with WO improved bone repair when compared with fractures treated only with WO.

  10. Limiter

    DOEpatents

    Cohen, Samuel A.; Hosea, Joel C.; Timberlake, John R.

    1986-01-01

    A limiter with a specially contoured front face accommodates the various power scrape-off distances .lambda..sub.p, which depend on the parallel velocity, V.sub..parallel., of the impacting particles. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution.

  11. History of POIC Capabilities and Limitations to Conduct International Space Station Payload Operations

    NASA Technical Reports Server (NTRS)

    Grimaldi, Rebecca; Horvath, Tim; Morris, Denise; Willis, Emily; Stacy, Lamar; Shell, Mike; Faust, Mark; Norwood, Jason

    2011-01-01

    Payload science operations on the International Space Station (ISS) have been conducted continuously twenty-four hours per day, 365 days a year beginning February, 2001 and continuing through present day. The Payload Operations Integration Center (POIC), located at the Marshall Space Flight Center in Huntsville, Alabama, has been a leader in integrating and managing NASA distributed payload operations. The ability to conduct science operations is a delicate balance of crew time, onboard vehicle resources, hardware up-mass to the vehicle, and ground based flight control team manpower. Over the span of the last ten years, the POIC flight control team size, function, and structure has been modified several times commensurate with the capabilities and limitations of the ISS program. As the ISS vehicle has been expanded and its systems changed throughout the assembly process, the resources available to conduct science and research have also changed. Likewise, as ISS program financial resources have demanded more efficiency from organizations across the program, utilization organizations have also had to adjust their functionality and structure to adapt accordingly. The POIC has responded to these often difficult challenges by adapting our team concept to maximize science research return within the utilization allocations and vehicle limitations that existed at the time. In some cases, the ISS and systems limitations became the limiting factor in conducting science. In other cases, the POIC structure and flight control team size were the limiting factors, so other constraints had to be put into place to assure successful science operations within the capabilities of the POIC. This paper will present the POIC flight control team organizational changes responding to significant events of the ISS and Shuttle programs.

  12. Improving Carbon Fixation Pathways

    PubMed Central

    Ducat, Daniel C.

    2012-01-01

    A recent resurgence in basic and applied research on photosynthesis has been driven in part by recognition that fulfilling future food and energy requirements will necessitate improvements in crop carbon-fixation efficiencies. Photosynthesis in traditional terrestrial crops is being reexamined in light of molecular strategies employed by photosynthetic microbes to enhance the activity of the Calvin cycle. Synthetic biology is well-situated to provide original approaches for compartmentalizing and enhancing photosynthetic reactions in a species independent manner. Furthermore, the elucidation of alternative carbon-fixation routes distinct from the Calvin cycle raises possibilities that alternative pathways and organisms can be utilized to fix atmospheric carbon dioxide into useful materials. PMID:22647231

  13. Improving carbon fixation pathways

    SciTech Connect

    Ducat, DC; Silver, PA

    2012-08-01

    A recent resurgence in basic and applied research on photosynthesis has been driven in part by recognition that fulfilling future food and energy requirements will necessitate improvements in crop carbon-fixation efficiencies. Photosynthesis in traditional terrestrial crops is being reexamined in light of molecular strategies employed by photosynthetic microbes to enhance the activity of the Calvin cycle. Synthetic biology is well-situated to provide original approaches for compartmentalizing and enhancing photosynthetic reactions in a species independent manner. Furthermore, the elucidation of alternative carbon-fixation routes distinct from the Calvin cycle raises possibilities that novel pathways and organisms can be utilized to fix atmospheric carbon dioxide into useful materials.

  14. Development of mathematical pediatric phantoms for internal dose calculations: designs, limitations, and prospects

    SciTech Connect

    Cristy, M.

    1980-01-01

    Mathematical phantoms of the human body at various ages are employed with Monte Carlo radiation transport codes for calculation of photon specific absorbed fractions. The author has developed a pediatric phantom series based on the design of the adult phantom, but with explicit equations for each organ so that organ sizes and marrow distributions could be assigned properly. Since the phantoms comprise simple geometric shapes, predictive dose capability is limited when geometry is critical to the calculation. Hence, there is a demand for better phantom design in situations where geometry is critical, such as for external irradiation or for internal emitters with low energy photons. Recent advances in computerized axial tomography (CAT) present the potential for derivation of anatomical information, which is so critical to development of phantoms, and ongoing developmental work on compuer architecture to handle large arrays for Monte Carlo calculations should make complex-geometry dose calculations economically feasible within this decade.

  15. Assessing the Performance Limits of Internal Coronagraphs Through End-to-End Modeling

    NASA Technical Reports Server (NTRS)

    Krist, John E.; Belikov, Ruslan; Pueyo, Laurent; Mawet, Dimitri P.; Moody, Dwight; Trauger, John T.; Shaklan, Stuart B.

    2013-01-01

    As part of the NASA ROSES Technology Demonstrations for Exoplanet Missions (TDEM) program, we conducted a numerical modeling study of three internal coronagraphs (PIAA, vector vortex, hybrid bandlimited) to understand their behaviors in realistically-aberrated systems with wavefront control (deformable mirrors). This investigation consisted of two milestones: (1) develop wavefront propagation codes appropriate for each coronagraph that are accurate to 1% or better (compared to a reference algorithm) but are also time and memory efficient, and (2) use these codes to determine the wavefront control limits of each architecture. We discuss here how the milestones were met and identify some of the behaviors particular to each coronagraph. The codes developed in this study are being made available for community use. We discuss here results for the HBLC and VVC systems, with PIAA having been discussed in a previous proceeding.

  16. Update: Biological Nitrogen Fixation.

    ERIC Educational Resources Information Center

    Wiseman, Alan; And Others

    1985-01-01

    Updates knowledge on nitrogen fixation, indicating that investigation of free-living nitrogen-fixing organisms is proving useful in understanding bacterial partners and is expected to lead to development of more effective symbioses. Specific areas considered include biochemistry/genetics, synthesis control, proteins and enzymes, symbiotic systems,…

  17. The Fixation of Nitrogen.

    ERIC Educational Resources Information Center

    Andrew, S. P. S.

    1978-01-01

    Discusses the fixation of atmospheric nitrogen in the form of ammonia as one of the foundations of modern chemical industry. The article describes ammonia production and synthesis, purifying the hydrogen-nitrogen mix, nitric acid production, and its commericial plant. (HM)

  18. Exposure limits for nanoparticles: report of an international workshop on nano reference values.

    PubMed

    van Broekhuizen, Pieter; van Veelen, Wim; Streekstra, Willem-Henk; Schulte, Paul; Reijnders, Lucas

    2012-07-01

    This article summarizes the outcome of the discussions at the international workshop on nano reference values (NRVs), which was organized by the Dutch trade unions and employers' organizations and hosted by the Social Economic Council in The Hague in September 2011. It reflects the discussions of 80 international participants representing small- and medium-size enterprises (SMEs), large companies, trade unions, governmental authorities, research institutions, and non-governmental organizations (NGOs) from many European countries, USA, India, and Brazil. Issues that were discussed concerned the usefulness and acceptability of precaution-based NRVs as a substitute for health-based occupational exposure limits (OELs) and derived no-effect levels (DNELs) for manufactured nanoparticles (NPs). Topics concerned the metrics for measuring NPs, the combined exposure to manufactured nanomaterials (MNMs) and process-generated NPs, the use of the precautionary principle, the lack of information about the presence of nanomaterials, and the appropriateness of soft regulation for exposure control. The workshop concluded that the NRV, as an 8-h time-weighted average, is a comprehensible and useful instrument for risk management of professional use of MNMs with a dispersible character. The question remains whether NRVs, as advised for risk management by the Dutch employers' organization and trade unions, should be under soft regulation or that a more binding regulation is preferable. PMID:22752096

  19. Amoco-Cadiz and limitation of liability for oil spill pollution: domestic and international solutions

    SciTech Connect

    Rosenthal, L.; Raper, C.

    1985-01-01

    On March 16, 1978, the supertanker Amoco Cadiz ran aground off the French coast after its steering gear failed in a storm. The ship spilled crude oil over 130 miles of the Brittany coast, severely damaging beaches and fishing grounds. It was the worst vessel-source oil pollution accident in the history of tanker transportation. In 1983, multiple suits arising from the accident were consolidated in the US District Court for the Northern District of Illinois. The court issued its interlocutory decision on liability on April 18, 1984. It held that Standard Oil Company and two of its subsidiaries were liable without limitation for the damage caused by the accident. This note first discusses the extent of environmental damage suffered when the oil spill occurred, and the legal significance of the case. It then reviews the court's findings of fact and conclusions of law. After a summary of American and international law applicable to such accidents, the note analyzes the decision. It concludes with suggestions for improving the present domestic and international legal systems regarding oil spill pollution. 291 references.

  20. [Stabilizing the pelvic ring with the external fixator. Biomechanical studies and clinical experiences].

    PubMed

    Egbers, H J; Draijer, F; Havemann, D; Zenker, W

    1992-11-01

    Experimental studies were performed on anatomic pelvis specimens. In different series of experiments the positioning of the screws and the assembly of the external fixator were changed. We tried fixing the external fixator to the screws at varying distances from the body surface. For stabilisation of the fractured pelvic girdle a self-constructed "bow fixator", fixed to supra-acetabular screws with proximal compression and distal traction showed the best results. Homogeneous distribution of the pressure could be achieved on the unstable dorsal pelvic ring structures. In clinical routine we used the triangular external fixator, which in the experimental situation yielded results close to those of the bow fixator. External fixation of the pelvic girdle has been performed 128 times since 1977, in January 1991 a prospective study was started. For Tile type B injuries the external fixator itself represents an effective, minimally invasive system, but type C fractures often require an additional internal fixation of the dorsal lesion. PMID:1475122

  1. Emerging Techniques for Posterior Fixation of the Lumbar Spine.

    PubMed

    Verma, Kushagra; Boniello, Anthony; Rihn, Jeffrey

    2016-06-01

    Pedicle screw fixation is the preferred method of posterior fusion in lumbar spinal surgery. The technique provides three-column support of the vertebrae, contributing to the biomechanical strength of the construct. However, open pedicle screw fixation often necessitates wide posterior exposure and dissection with soft-tissue disruption of the facet joint. Alternative posterior fixation techniques have been developed to reduce surgical time, soft-tissue dissection, disruption of the adjacent facet joint capsule, neurologic risk, and implant cost. Results of these techniques are comparable to those of standard pedicle screw fixation systems. Certain patients, especially those at a lower risk of nonunion or those who require posterior fixation only as an adjunct to anterior column support, may benefit from the shorter surgical time and limited posterior exposure of the alternative techniques. However, the decreased rigidity of these alternative constructs can result in excessive motion, which can lead to nonunion and early hardware failure. PMID:27077477

  2. Cementless fixation in total knee arthroplasty: past, present, and future.

    PubMed

    Meneghini, R Michael; Hanssen, Arlen D

    2008-10-01

    Cementless fixation in total knee arthroplasty (TKA) has had limited use in recent decades due to past failures in the early generation of cementless designs. Screw track osteolysis, poor polyethylene, and metal-backed patellar component failures contributed to a controversial track record and created a reluctance to embrace cementless fixation in TKA; however, these failure mechanisms are correctable. In addition, there is renewed interest in cementless fixation due to the recent development of improved biomaterials, particularly highly porous metals and highly crosslinked polyethylene, as well as time-saving advantages and long-term osseointegration of cementless fixation. There are long-term reports of successful designs of cementless knee arthroplasty that are nearly equal to the results of cemented designs. This article discusses the past history, current long-term results, and future of cementless fixation in TKA. PMID:18979934

  3. Novel posterior fixation keratoprosthesis

    NASA Astrophysics Data System (ADS)

    Lacombe, Emmanuel

    1992-08-01

    The keratoprosthesis is the last solution for corneally blind patients that cannot benefit from corneal transplants. Keratoprostheses that have been designed to be affixed anteriorly usually necessitate multi-step surgical procedures and are continuously subjected to the extrusion forces generated by the positive intraocular pressure; therefore, clinical results in patients prove inconsistent. We proposed a novel keratoprosthesis concept that utilizes posterior corneal fixation which `a priori' minimizes the risk of aqueous leakage and expulsion. This prosthesis is implanted in a single procedure thereby reducing the number of surgical complications normally associated with anterior fixation devices. In addition, its novel design makes this keratoprosthesis implantable in phakic eyes. With an average follow-up of 13 months (range 3 to 25 months), our results on 21 cases are encouraging. Half of the keratoprostheses were implanted in severe burn cases, with the remainder in cases of pseudo- pemphigus. Good visual results and cosmetic appearance were obtained in 14 of 21 eyes.

  4. Sludge fixation and stabilization

    SciTech Connect

    Smith, R.H.

    1982-08-03

    The physical and chemical fixation and stabilization of waste products from a sulfur-fuel burning unit through controlled crystallization of dissolved calcium sulfite. A low ph calcium sulfite solution is added to the waste containing aqueous sludge produced by a gas desulfurization unit thereby raising the ph of the calcium sulfite to crystalize the calcium sulfite and bind and encapsulate the waste products into a solid mass.

  5. CARBON DIOXIDE FIXATION.

    SciTech Connect

    FUJITA,E.

    2000-01-12

    Solar carbon dioxide fixation offers the possibility of a renewable source of chemicals and fuels in the future. Its realization rests on future advances in the efficiency of solar energy collection and development of suitable catalysts for CO{sub 2} conversion. Recent achievements in the efficiency of solar energy conversion and in catalysis suggest that this approach holds a great deal of promise for contributing to future needs for fuels and chemicals.

  6. Low Carbon Costs of Nitrogen Fixation in Tropical Dry Forests

    NASA Astrophysics Data System (ADS)

    Gei, M. G.; Powers, J. S.

    2015-12-01

    Legume tree species with the ability to fix nitrogen (N) are highly diverse and widespread across tropical forests but in particular in the dry tropics. Their ecological success in lower latitudes has been called a "paradox": soil N in the tropics is thought to be high, while acquiring N through fixation incurs high energetic costs. However, the long held assumptions that N fixation is limited by photosynthate and that N fixation penalizes plant productivity have rarely been tested, particularly in legume tree species. We show results from three different experiments where we grew eleven species of tropical dry forest legumes. We quantified plant biomass and N fixation using nodulation and the 15N natural isotope abundance (Ndfa or nitrogen derived from fixation). These data show little evidence for costs of N fixation in seedlings grown under different soil fertility, light regimes, and with different microbial communities. Seedling productivity did not incur major costs because of N fixation: indeed, the average slope between Ndfa and biomass was positive (range in slopes: -0.03 to 0.3). Moreover, foliar N, which varied among species, was tightly constrained and not correlated with Ndfa. This finding implies that legume species have a target N that does not change depending on N acquisition strategies. The process of N fixation in tropical legumes may be more carbon efficient than previously thought. This view is more consistent with the hyperabundance of members of this family in tropical ecosystems.

  7. Speed limit in internal space of domain walls via all-order effective action of moduli motion

    NASA Astrophysics Data System (ADS)

    Eto, Minoru; Hashimoto, Koji

    2016-03-01

    We find that motion in internal moduli spaces of generic domain walls has an upper bound for its velocity. Our finding is based on our generic formula for all-order effective actions of internal moduli parameter of domain wall solitons. It is known that the Nambu-Goldstone mode Z associated with spontaneous breaking of translation symmetry obeys a Nambu-Goto effective Lagrangian √{1 -(∂0Z )2 } detecting the speed of light (|∂0Z |=1 ) in the target spacetime. Solitons can have internal moduli parameters as well, associated with a breaking of internal symmetries such as a phase rotation acting on a field. We obtain, for generic domain walls, an effective Lagrangian of the internal moduli ɛ to all orders in (∂ɛ ). The Lagrangian is given by a function of the Nambu-Goto Lagrangian: L =g (√{1 +(∂μɛ )2 }). This shows generically the existence of an upper bound on ∂0ɛ , i.e., a speed limit in the internal space. The speed limit exists even for solitons in some nonrelativistic field theories, where we find that ɛ is a type I Nambu-Goldstone mode that also obeys a nonlinear dispersion to reach the speed limit. This offers a possibility of detecting the speed limit in condensed matter experiments.

  8. Can retinal microtrauma by internal limiting membrane peeling cause retinal angiomatosis proliferans?

    PubMed Central

    Rishi, Pukhraj; Dhupper, Maneesh; Rishi, Ekta

    2011-01-01

    A 32-year-old male presented with decreased vision in right eye since 1 month following trauma with plastic ball. Best-corrected visual acuity (BCVA) was 20/160 in right eye and 20/20 in left. Right eye examination revealed angle recession, choroidal rupture, and macular hole. He underwent vitrectomy, internal limiting membrane (ILM) peeling, and 14% C3F8 gas injection. After 6 weeks, BCVA was 20/30; fundus showed macular hole closure. Six months after surgery, fundus revealed retinal vascular lesions suggestive of stage I RAP-like lesions; vision was maintained. Clinical findings were confirmed on Video ICGA, FFA, and OCT. The patient was periodically reviewed and lesions were nonprogressive until last follow-up, 13 months after surgery. It seems quite probable that ILM peeling may have caused retinal microtrauma leading to the formation of RAP-like lesions. What factors lead to such an event is as yet not clearly understood. Hence, larger studies with a longer follow-up are warranted to better understand these findings. PMID:22279405

  9. Viscoat Assisted Inverted Internal Limiting Membrane Flap Technique for Large Macular Holes Associated with High Myopia

    PubMed Central

    Song, Zongming; Li, Mei; Liu, Junjie; Hu, Xuting; Hu, Zhixiang

    2016-01-01

    Purpose. To investigate the surgical outcomes of Viscoat® assisted inverted internal limiting membrane (ILM) flap technique for large macular holes (MHs) associated with high myopia. Design. Prospective, interventional case series. Methods. Fifteen eyes of 15 patients with high myopia underwent vitrectomy and Viscoat assisted inverted ILM flap technique to treat MH without RD. Patients were followed up over 6 months. The main outcome measures were MH closure evaluated by optical coherence tomography (OCT) and best-corrected visual acuities (BCVAs). Result. MH closure was observed in all eyes (100%) following the initial surgery. Type 1 closure was observed in 13 eyes (86.7%); type 2 closure was observed in the remaining 2 eyes (13.3%). Compared to the preoperative baseline, the mean BCVA (logarithm of the minimum angle of resolution) improved significantly at 3 months and 6 months after surgery (P = 0.025, 0.019, resp.). The final BCVA improved in 10 eyes (66.7%), remained unchanged in 3 eyes (20.0%), and worsened in 2 eyes (13.3%). Conclusion. Vitrectomy combined with Viscoat assisted inverted ILM flap technique is an effective treatment for large MHs in highly myopic eyes. It may increase the success rate of the initial surgery and enhance the anatomical and functional outcomes. PMID:27047686

  10. Biomechanical Study of Acetabular Tridimensional Memoryalloy Fixation System

    NASA Astrophysics Data System (ADS)

    Liu, Xin-Wei; Xu, Shuo-Gui; Zhang, Yun-Tong; Zhang, Chun-Cai

    2011-07-01

    We developed the acetabular tridimensional memoryalloy fixation system (ATMFS), which is made of NiTi shape memory alloy, according to the specific mechanical properties of biological memory material, NiTi shape memory alloy and measured distribution of contact area and pressure between the acetabulum and the femoral head of cadaveric pelvis. Seven formalin-preserved cadaveric pelves were used for this investigation. Pressure-sensitive film was used to measure contact area and pressure within the anterior, superior, and posterior regions of the acetabulum. The pelves were loaded under the following four conditions: (1) intact; (2) following a creation posterior wall fracture defect; (3) following reduction and standard internal fixation with reconstruction plate; and (4) following reduction and internal fixation with a new shape memory alloy device named ATMFS. A posterior wall fracture was created along an arc of 40° to 90° about the acetabulur rim. Creation of a posterior wall defect resulted in increased load in the superior acetabulum (1485 N) as compared to the intact condition (748 N, P = 0.009). Following reduction and internal fixation, the load distributed to the superior acetabulum (1545 N) was not statistically different from the defect condition. Following the fixation with ATMFS, the load seen at the superior region of the actabulum (964 N) was familiar with fixation with reconstruction plate and was not different from intact state ( P = 0.45). These data indicate that the use of ATMFS as a fracture internal fixation device resulted a partial restoration of joint loading parameters toward the intact state. ATMFS fixation may result in a clinical benefit.

  11. Fiber-matrix interface studies on bioabsorbable composite materials for internal fixation of bone fractures. I. Raw material evaluation and measurement of fiber-matrix interfacial adhesion.

    PubMed

    Slivka, M A; Chu, C C; Adisaputro, I A

    1997-09-15

    The objective of this study was to characterize and evaluate the performance of various fiber-matrix composite systems by studying the mechanical, thermal, and physical properties of the fiber and matrix components, and by studying the fiber-matrix interface adhesion strength using both microbond and fragmentation methods. The composites studies were poly(L-lactic acid) (PLLA) matrix reinforced with continuous fibers of either nonabsorbable AS4 carbon (C), absorbable calcium phosphate (CaP), poly(glycolic acid) (PGA), or chitin. Carbon and CaP single fibers had high Young's moduli and failed in a brittle manner. PGA and chitin single fibers had relatively lower Young's moduli and relatively higher ductility. Upon in vitro hydrolysis, CaP fibers retained 17% of their tensile strength and 39% of their Young's modulus after 12 h, PCA fibers retained 10% of their tensile strength and 52% of their Young's modulus after 16 days, and chitin fibers retained 87% of their tensile strength and 130% of their Young's modulus after 25 days. PLLA films had much lower strength and Young's moduli, but much higher ductility relative to the single fibers. Using the microbond method, the initial fiber-matrix interfacial shear strength (IFSS) of C/PLLA and CaP/PLLA microcomposites was 33.9 and 12.6 MPa, respectively. Upon in vitro hydrolysis, C/PLLA retained 49% of IFSS after 15 days and CaP/PLLA retained 46% of IFSS after 6 h. Using a fiber fragmentation method, the initial IFSS of C/PLLA, CaP/PLLA, and chitin/ PLLA was 22.2, 15.6, and 28.3 MPa, respectively. The performance of carbon fibers and C/PLLA composites was superior to the other fibers and fiber/PLLA systems, but the carbon fiber was nonabsorbable. CaP had the most suitable modulus of the absorbable fibers for fixing cortical bone fracture, but its rapid deterioration of mechanical properties and loss of IFSS limits its use. PGA and chitin fibers had suitable mechanical properties and their retention for fixing cancellous

  12. A Thickened Coracohumeral Ligament and Superomedial Capsule Limit Internal Rotation of the Shoulder Joint: Report of Three Cases

    PubMed Central

    Koide, Masashi; Hamada, Junichiro; Hagiwara, Yoshihiro; Kanazawa, Kenji; Suzuki, Kazuaki

    2016-01-01

    Adhesive capsulitis of the shoulder (also known as frozen shoulder) is a painful and disabling disorder with an estimated prevalence ranging from 2% to 5% in the general population. Although the precise pathogenesis of frozen shoulder is unclear, thickened capsule and coracohumeral ligament (CHL) have been documented to be one of the most specific manifestations. The thickened CHL has been understood to limit external rotation of the shoulder, and restriction of internal rotation of the shoulder has been believed to be related to posterior capsular tightness. In this paper, three cases of refractory frozen shoulder treated through arthroscopic release of a contracted capsule including CHL were reported. Two cases in which there is recalcitrant severe restriction of internal rotation after manipulation under anesthesia (MUA) were finally treated with arthroscopic surgery. Although MUA could release the posterior capsule, internal rotation did not improve in our cases. After release of the thickened CHL, range of motion of internal rotation was significantly improved. This report demonstrates the role of the thickened CHL in limiting the internal rotation of the shoulder. We highlight the importance of release of thickened CHL in addition to the pancapsular release, in case of severe limitation of internal rotation of shoulder. PMID:27123353

  13. Photoreceptor Outer Segment on Internal Limiting Membrane after Macular Hole Surgery: Implications for Pathogenesis

    PubMed Central

    Grinton, Michael E.; Sandinha, Maria T.; Steel, David H.W.

    2015-01-01

    Purpose This report presents a case, which highlights key principles in the pathophysiology of macular holes. It has been hypothesized that anteroposterior (AP) and tangential vitreous traction on the fovea are the primary underlying factors causing macular holes [Nischal and Pearson; in Kanski and Bowling: Clinical Ophthalmology: A Systemic Approach, 2011, pp 629–631]. Spectral domain optical coherence tomography (OCT) has subsequently corroborated this theory in part but shown that AP vitreofoveal traction is the more common scenario [Steel and Lotery: Eye 2013;27:1–21]. Methods This study was conducted as a single case report. Results A 63-year old female presented to her optician with blurred and distorted vision in her left eye. OCT showed a macular hole with a minimum linear diameter of 370 µm, with persistent broad vitreofoveal attachment on both sides of the hole edges. The patient underwent combined left phacoemulsification and pars plana vitrectomy, internal limiting membrane (ILM) peel and gas injection. The ILM was examined by electron microscopy and showed the presence of a cone outer segment on the retinal side. Post-operative OCT at 11 weeks showed a closed hole with recovery of the foveal contour and good vision. Conclusion Our case shows the presence of a photoreceptor outer segment on the retinal side of the ILM and reinforces the importance of tangential traction in the development of some macula holes. The case highlights the theory of transmission of inner retinal forces to the photoreceptors via Müller cells and how a full thickness macular hole defect can occur in the absence of AP vitreomacular traction. PMID:26557083

  14. A unifying framework for dinitrogen fixation in the terrestrial biosphere.

    PubMed

    Houlton, Benjamin Z; Wang, Ying-Ping; Vitousek, Peter M; Field, Christopher B

    2008-07-17

    Dinitrogen (N(2)) fixation is widely recognized as an important process in controlling ecosystem responses to global environmental change, both today and in the past; however, significant discrepancies exist between theory and observations of patterns of N(2) fixation across major sectors of the land biosphere. A question remains as to why symbiotic N(2)-fixing plants are more abundant in vast areas of the tropics than in many of the mature forests that seem to be nitrogen-limited in the temperate and boreal zones. Here we present a unifying framework for terrestrial N(2) fixation that can explain the geographic occurrence of N(2) fixers across diverse biomes and at the global scale. By examining trade-offs inherent in plant carbon, nitrogen and phosphorus capture, we find a clear advantage to symbiotic N(2) fixers in phosphorus-limited tropical savannas and lowland tropical forests. The ability of N(2) fixers to invest nitrogen into phosphorus acquisition seems vital to sustained N(2) fixation in phosphorus-limited tropical ecosystems. In contrast, modern-day temperatures seem to constrain N(2) fixation rates and N(2)-fixing species from mature forests in the high latitudes. We propose that an analysis that couples biogeochemical cycling and biophysical mechanisms is sufficient to explain the principal geographical patterns of symbiotic N(2) fixation on land, thus providing a basis for predicting the response of nutrient-limited ecosystems to climate change and increasing atmospheric CO(2). PMID:18563086

  15. Comparison of the mechanical performance of trochanteric fixation devices.

    PubMed

    Hersh, C K; Williams, R P; Trick, L W; Lanctot, D; Athanasiou, K

    1996-08-01

    The transtrochanteric surgical approach to the hip is commonly used, especially for revision hip surgery. Failure of the trochanter to heal can lead to hardware failure, persistent pain, and limp. Rigid internal fixation is needed in this approach to achieve an adequate rate of healing. Newer cable and cable grip systems have been designed to improve trochanteric fixation, but have not been compared to the older Charnley wire fixation techniques. In this study, an in vitro mechanical method previously used to test wire fixation methods was used to compare wire, cable, and cable grip fixation methods. A quasistatic mechanical distraction device was used to compare structural stiffness, load to clinical failure, energy to clinical failure, and maximum load resisted by the fixation devices. The cable grip system was found to be stiffer, to resist a larger load to mechanical failure at 1-cm displacement, and to absorb a greater amount of energy to clinical failure when compared with the other systems. These data suggest that use of the cable grip fixation method should result in improved clinical success compared with the Charnley wire technique. PMID:8769467

  16. Nitrogen fixation apparatus

    DOEpatents

    Chen, Hao-Lin

    1984-01-01

    A method and apparatus for achieving nitrogen fixation includes a volumetric electric discharge chamber. The volumetric discharge chamber provides an even distribution of an electron beam, and enables the chamber to be maintained at a controlled energy to pressure (E/p) ratio. An E/p ratio of from 5 to 15 kV/atm of O.sub.2 /cm promotes the formation of vibrationally excited N.sub.2. Atomic oxygen interacts with vibrationally excited N.sub.2 at a much quicker rate than unexcited N.sub.2, greatly improving the rate at which NO is formed.

  17. Treatment of Unstable Thoracolumbar Fractures through Short Segment Pedicle Screw Fixation Techniques Using Pedicle Fixation at the Level of the Fracture: A Finite Element Analysis

    PubMed Central

    Li, Changqing; Zhou, Yue; Wang, Hongwei; Liu, Jun; Xiang, Liangbi

    2014-01-01

    Objective To compare the von Mises stresses of the internal fixation devices among different short segment pedicle screw fixation techniques to treat thoracic 12 vertebral fractures, especially the mono-segment pedicle screw fixation and intermediate unilateral pedicle screw fixation techniques. Methods Finite element methods were utilised to investigate the biomechanical comparison of the four posterior short segment pedicle screw fixation techniques (S4+2: traditional short-segment 4 pedicle screw fixation [SPSF]; M4+2: mono-segment pedicle screw fixation; I6+2: intermediate bilateral pedicle screw fixation; and I5+2: intermediate unilateral pedicle screw fixation). Results The range of motion (ROM) in flexion, axial rotation, and lateral bending was the smallest in the I6+2 fixation model, followed by the I5+2 and S4+2 fixation models, but lateral bending was the largest in the M4+2 fixation model. The maximal stress of the upper pedicle screw is larger than the lower pedicle screw in S4+2 and M4+2. The largest maximal von Mises stress was observed in the upper pedicle screw in the S4+2 and M4+2 fixation models and in the lower pedicle screw in the I6+2 and I5+2 fixation models. The values of the largest maximal von Mises stress of the pedicle screws and rods during all states of motion were 263.1 MPa and 304.5 MPa in the S4+2 fixation model, 291.6 MPa and 340.5 MPa in the M4+2 fixation model, 182.9 MPa and 263.2 MPa in the I6+2 fixation model, and 269.3 MPa and 383.7 MPa in the I5+2 fixation model, respectively. Comparing the stress between different spinal loadings, the maximal von Mises stress of the implants were observed in flexion in all implanted models. Conclusion Additional bilateral pedicle screws at the level of the fracture to SPSF may result in a stiffer construct and less von Mises stress for pedicle screws and rods. The largest maximal von Mises stress of the pedicle screws during all states of motion were observed in the mono-segment pedicle

  18. National and International School Performance Studies: What Can They Do, What Are Their Limits?

    ERIC Educational Resources Information Center

    Baumert, Jurgen; Koller, Olaf

    2000-01-01

    Summarizes the most important results of two international studies, the Educational Careers and Psychosocial Development in Youth (ECPDY) and the Third International Mathematics and Science Study (TIMSS). Addresses the problems of measuring school achievement and determining social behavior and other attributes. (CMK)

  19. Anticipatory eye fixations reveal tool knowledge for tool interaction.

    PubMed

    Belardinelli, Anna; Barabas, Marissa; Himmelbach, Marc; Butz, Martin V

    2016-08-01

    Action-oriented eye-tracking studies have shown that eye fixations reveal much about current behavioral intentions. The eyes typically fixate those positions of a tool or an object where the fingers will be placed next, or those positions in a scene, where obstacles need to be avoided to successfully reach or transport a tool or object. Here, we asked to what extent eye fixations can also reveal active cognitive inference processes, which are expected to integrate bottom-up visual information with internal knowledge for planning suitable object interactions task-dependently. In accordance to the available literature, we expected that task-relevant knowledge will include sensorimotor, semantic, and mechanical aspects. To investigate if and in which way this internal knowledge influences eye fixation behavior while planning an object interaction, we presented pictures of familiar and unfamiliar tools and instructed participants to either pantomime 'lifting' or 'using' the respective tool. When confronted with unfamiliar tools, participants fixated the tool's effector part closer and longer in comparison with familiar tools. This difference was particularly prominent during 'using' trials when compared with 'lifting' trials. We suggest that this difference indicates that the brain actively extracts mechanical information about the unknown tool in order to infer its appropriate usage. Moreover, the successive fixations over a trial indicate that a dynamic, task-oriented, active cognitive process unfolds, which integrates available tool knowledge with visually gathered information to plan and determine the currently intended tool interaction. PMID:27068808

  20. 75 FR 9017 - Orders Limiting Scheduled Operations at John F. Kennedy International Airport, LaGuardia Airport...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-26

    ... CFR Sec. 93.227 (DCA); 74 FR 51648 (Oct. 7, 2009) (EWR); 74 FR 51650 (Oct. 7, 2009) (JFK); 74 FR 51653... Airport, LaGuardia Airport and Newark Liberty International Airport; High Density Rule at Reagan National... Density Rule and orders limiting scheduled operations at the airports, slots must be used at least...

  1. Risk of Anterior Cruciate Ligament Fatigue Failure Is Increased by Limited Internal Femoral Rotation During In Vitro Repeated Pivot Landings

    PubMed Central

    Beaulieu, Mélanie L.; Wojtys, Edward M.; Ashton-Miller, James A.

    2015-01-01

    Background A reduced range of hip internal rotation is associated with increased peak anterior cruciate ligament (ACL) strain and risk for injury. It is unknown, however, whether limiting the available range of internal femoral rotation increases the susceptibility of the ACL to fatigue failure. Hypothesis Risk of ACL failure is significantly greater in female knee specimens with a limited range of internal femoral rotation, smaller femoral-ACL attachment angle, and smaller tibial eminence volume during repeated in vitro simulated single-leg pivot landings. Study Design Controlled laboratory study. Methods A custom-built testing apparatus was used to simulate repeated single-leg pivot landings with a 4×-body weight impulsive load that induces knee compression, knee flexion, and internal tibial torque in 32 paired human knee specimens from 8 male and 8 female donors. These test loads were applied to each pair of specimens, in one knee with limited internal femoral rotation and in the contralateral knee with femoral rotation resisted by 2 springs to simulate the active hip rotator muscles’ resistance to stretch. The landings were repeated until ACL failure occurred or until a minimum of 100 trials were executed. The angle at which the ACL originates from the femur and the tibial eminence volume were measured on magnetic resonance images. Results The final Cox regression model (P = .024) revealed that range of internal femoral rotation and sex of donor were significant factors in determining risk of ACL fatigue failure. The specimens with limited range of internal femoral rotation had a failure risk 17.1 times higher than did the specimens with free rotation (P = .016). The female knee specimens had a risk of ACL failure 26.9 times higher than the male specimens (P = .055). Conclusion Limiting the range of internal femoral rotation during repetitive pivot landings increases the risk of an ACL fatigue failure in comparison with free rotation in a cadaveric model

  2. Technical tips: dualplate fixation technique for comminuted proximal humerus fractures.

    PubMed

    Choi, Sungwook; Kang, Hyunseong; Bang, Hyeongsig

    2014-08-01

    The authors report dualplate fixation technique for providing stable fixation in comminuted proximal humerus fractures. This technique has been used for proximal humerus fractures with metaphyseal comminution and provides excellent anatomical reduction and neck shaft angle (NSA). The recently locking plate is clinically more widely used due to its small size, low rigidity, high elasticity, and biomechanical properties such as fixed initial angle and rotational stability. However, in severely comminuted complex type proximal metaphyseal humerus fractures, the use of locking plate alone does not provide stable fixation, leading to complications such as varus collapse, anterior-posterior angulation, screw cutout, nonunion, malunion, and metal failure. Therefore, a more robust and enhanced fixation method, the dual plating technique using the locking compression plate (Proximal Humeral Internal Locking System and Variable Angle Locking Compression Plate) was developed. PMID:24813097

  3. Fixation versus hemiarthroplasty for undisplaced intracapsular hip fractures.

    PubMed

    Parker, Martyn J; White, Andrew; Boyle, Adrian

    2008-07-01

    The conventional treatment for an undisplaced intracapsular hip fracture is internal fixation. A possible alternative treatment is replacement hemiarthroplasty. We have compared the outcomes of an age, sex and co-morbidity matched cohort of 346 patients who have had their undisplaced intracapsular hip fracture treated using cannulated screws with a group of 346 patients who have had a displaced intracapsular fracture treated using a hemiarthroplasty. Patients treated by internal fixation had a shorter operation time (43 versus 67 min), reduced orthopaedic ward stay (11 versus 15 days), lower incidence of peri-operative complications (24 versus 81), and a lower 1-year mortality (19% versus 26%). Additional benefits for the fixation group were less pain at 1 year, less reduction in mobility and lower dependence on walking aids. All these differences were statistically significant. Hemiarthroplasty had a lower re-admission rate (43 versus 14 cases) and re-operation rate (59 versus 22 cases). These results support the use of internal fixation for undisplaced intracapsular fractures and confirm that the final outcome for an undisplaced intracapsular hip fracture is significantly better than for a displaced intracapsular fracture, despite a higher re-operation rate after internal fixation. PMID:18407277

  4. Vitrectomy and internal limiting membrane peeling for macular folds secondary to hypotony in myopes

    PubMed Central

    Nadal, Jeroni; Carreras, Elisa; Canut, Maria Isabel; Barraquer, Rafael I

    2015-01-01

    Background Hypotony maculopathy (HM) changes may persist, and visual acuity remains poor, despite normalization of intraocular pressure (IOP). The aim of this study was to evaluate the visual and anatomical results of pars plana vitrectomy (PPV), internal limiting membrane (ILM) peeling, and 20% SF6 gas tamponade in five myopic patients with HM. Methods This retrospective interventional study was conducted at the Barraquer Center of Ophthalmology, a tertiary care center in Barcelona, Spain, and included five eyes from five consecutive patients (aged 55.4±13.1 years) with HM caused by different conditions. All the patients were treated with 23-gauge PPV, ILM peeling, and 20% SF6 gas tamponade. Preoperative and postoperative evaluation was performed using anterior and posterior biomicroscopy and best corrected visual acuity (BCVA) by logMAR charts. Results Before surgery, median spherical equivalent was −13.1 (range −7, −19) diopters of myopia. Preoperatively, four cases presented IOP <6.5 mmHg for 3 (range 2–8) weeks. In three of these four cases, IOP >6.5 mmHg was achieved over 16 (range 16–28) weeks, without resolution of HM; increased IOP was not achieved in the remaining case treated 2 weeks after diagnosis of HM. One case presented IOP >6.5 mmHg with HM for 28 weeks before surgery. Preoperative BCVA was 0.7 (range 0.26–2.3) logMAR, and 0.6 (range 0.3–0.7) logMAR and 0.5 (range 0.2–1) logMAR, respectively, at 4 and 12 months after surgery. There was no statistically significant difference between preoperative and postoperative BCVA. Hyper-pigmentation lines in the macular area were observed in three cases with hypotony. These lines progressed after surgery despite resolution of the retinal folds in the three cases, and BCVA decreased in parallel in two of these cases. Conclusion PPV with ILM peeling followed by gas tamponade is a good alternative for the treatment of HM in myopic patients. However, persistent choroidal folds may compromise BCVA

  5. Diurnal variation in n(2) fixation and photosynthesis by aquatic blue-green algae.

    PubMed

    Peterson, R B; Friberg, E E; Burris, R H

    1977-01-01

    Rates of (14)CO(2) fixation, O(2) evolution, and N(2) fixation (acetylene reduction) by natural populations of blue-green algae recovered from Lake Mendota were measured at frequent intervals between sunrise and sunset. Photosynthesis and N(2) fixation were depressed during midday when light intensity was greatest. As the light intensity rose, most of the algal population migrated to deeper, light-limited waters where radiation damage would be diminished. As the relative rate of N(2) fixation compared to CO(2) fixation increases with depth, it is suggested that the algae maintain balanced growth by migrating vertically via buoyancy regulation. High concentrations of dissolved O(2) in lake water may inhibit N(2) fixation by enhancing photorespiration. Several factors such as photosynthetic rate, light intensity, dissolved O(2), species composition, and vertical and horizontal migration all affect observed rates of in situ N(2) fixation. PMID:16659792

  6. Diurnal Variation in N2 Fixation and Photosynthesis by Aquatic Blue-Green Algae 1

    PubMed Central

    Peterson, Richard B.; Friberg, Eugene E.; Burris, R. H.

    1977-01-01

    Rates of 14CO2 fixation, O2 evolution, and N2 fixation (acetylene reduction) by natural populations of blue-green algae recovered from Lake Mendota were measured at frequent intervals between sunrise and sunset. Photosynthesis and N2 fixation were depressed during midday when light intensity was greatest. As the light intensity rose, most of the algal population migrated to deeper, light-limited waters where radiation damage would be diminished. As the relative rate of N2 fixation compared to CO2 fixation increases with depth, it is suggested that the algae maintain balanced growth by migrating vertically via buoyancy regulation. High concentrations of dissolved O2 in lake water may inhibit N2 fixation by enhancing photorespiration. Several factors such as photosynthetic rate, light intensity, dissolved O2, species composition, and vertical and horizontal migration all affect observed rates of in situ N2 fixation. PMID:16659792

  7. Biomechanical Analysis of the Fixation System for T-Shaped Acetabular Fracture

    PubMed Central

    Fan, Yanping; Lei, Jianyin; Zhu, Feng; Li, Zhiqiang; Chen, Weiyi; Liu, Ximing

    2015-01-01

    This study aims to evaluate the biomechanical mechanism of fixation systems in the most frequent T-shaped acetabular fracture using finite element method. The treatment of acetabular fractures was based on extensive clinical experience. Three commonly accepted rigid fixation methods (double column reconstruction plates (P × 2), anterior column plate combined with posterior column screws (P + PS), and anterior column plate combined with quadrilateral area screws (P + QS)) were chosen for evaluation. On the basis of the finite element model, the biomechanics of these fixation systems were assessed through effective stiffness levels, stress distributions, force transfers, and displacements along the fracture lines. All three fixation systems can be used to obtain effective functional outcomes. The third fixation system (P + QS) was the optimal method for T-shaped acetabular fracture. This fixation system may reduce many of the risks and limitations associated with other fixation systems. PMID:26495030

  8. 77 FR 1549 - Order Limiting Scheduled Operations at Newark Liberty International Airport

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-10

    ... runway construction project at John F. Kennedy International Airport.\\1\\ \\1\\ 74 FR 52838 (Oct. 14, 2009... grant general waivers to the usage requirement except under the most unusual circumstances. \\3\\ 76...

  9. Characteristics of Fixational Eye Movements in People With Macular Disease

    PubMed Central

    Kumar, Girish; Chung, Susana T. L.

    2014-01-01

    Purpose. Fixation stability is known to be poor for people with macular disease and has been suggested as a contributing factor for the poor visual performance of these individuals. In this study, we examined the characteristics of the different components of fixational eye movements and determined the component that plays a major role in limiting fixation stability in people with macular disease. Methods. Sixteen observers with macular disease and 14 older adults with normal vision (control observers) monocularly fixated a small cross presented using a Rodenstock scanning laser ophthalmoscope, for trials of 30 seconds. The retinal image and the position of the cross on the retina were recorded digitally. Eye movements were extracted from the recorded videos at a sampling rate of 540 Hz using a cross-correlation technique. A velocity criterion of 8°/s was used to differentiate between slow drifts and microsaccades. Results. Observers with macular disease demonstrated higher fixation instability, larger amplitudes of slow drifts and microsaccades, and lower drift velocities, when compared with older adults with normal vision. The velocity and the rate of microsaccades were comparable between the two groups of observers. Multiple linear regression analysis showed that the amplitude of microsaccades, and to a smaller extent, the amplitude of slow drifts, play a major role in limiting fixation stability. Conclusions. Fixation stability in people with macular disease is primarily limited by the amplitude of microsaccades, implying that rehabilitative strategies targeted at reducing the amplitude of microsaccades should improve fixation stability, and may lead to improved visual functions. PMID:25074769

  10. External fixation of distal radius fractures.

    PubMed

    Slutsky, David J

    2007-12-01

    External fixation has been used for the treatment of distal radius fractures for more than 50 years. Although the fixator configurations have undergone considerable modification over time, the type of fixator itself is not as important as the underlying principles that provide the foundation for external fixation. Although volar plate fixation is currently in vogue, the indications for external fixation remain largely unchanged. Newer fixator designs have also expanded the traditional usage to include nonbridging applications that allow early wrist motion. The following discussion focuses on the myriad uses for external fixation as well as the shortcomings and potential pitfalls. PMID:18070654

  11. Fixation by active accommodation

    NASA Astrophysics Data System (ADS)

    Pahlavan, Kourosh; Uhlin, Tomas; Eklundh, Jan-Olof

    1992-11-01

    The field of computer vision has long been interested in disparity as the cue for the correspondence between stereo images. The other cue to correspondence, blur, and the fact that vergence is a combination of the two processes, accommodative vergence and disparity vergence, have not been equally appreciated. Following the methodology of active vision that allows the observer to control all his visual parameters, it is quite natural to take advantage of the powerful combination of these two processes. In this article, we try to elucidate such an integration and briefly analyze the cooperation and competition between accommodative vergence and disparity vergence on one hand and disparity and blur stimuli on the other hand. The human fixation mechanism is used as a guide-line and some virtues of this mechanism are used to implement a model for vergence in isolation. Finally, some experimental results are reported.

  12. Biomechanical characteristics of C1-2 cable fixations.

    PubMed

    Dickman, C A; Crawford, N R; Paramore, C G

    1996-08-01

    and graft site. After the specimen was fatigued, the axes of rotation became more widely dispersed but were usually still localized near the cable and graft site. Adequate healing requires satisfactory control of C1-2 motion. Therefore, some adjunctive fixation is advocated to supplement the control of motion after C1-2 cable fixation (that is, a cervical collar, a halo brace, or rigid internal fixation with transarticular screws). PMID:8755762

  13. Visual recovery in cortical blindness is limited by high internal noise.

    PubMed

    Cavanaugh, Matthew R; Zhang, Ruyuan; Melnick, Michael D; Das, Anasuya; Roberts, Mariel; Tadin, Duje; Carrasco, Marisa; Huxlin, Krystel R

    2015-01-01

    Damage to the primary visual cortex typically causes cortical blindness (CB) in the hemifield contralateral to the damaged hemisphere. Recent evidence indicates that visual training can partially reverse CB at trained locations. Whereas training induces near-complete recovery of coarse direction and orientation discriminations, deficits in fine motion processing remain. Here, we systematically disentangle components of the perceptual inefficiencies present in CB fields before and after coarse direction discrimination training. In seven human CB subjects, we measured threshold versus noise functions before and after coarse direction discrimination training in the blind field and at corresponding intact field locations. Threshold versus noise functions were analyzed within the framework of the linear amplifier model and the perceptual template model. Linear amplifier model analysis identified internal noise as a key factor differentiating motion processing across the tested areas, with visual training reducing internal noise in the blind field. Differences in internal noise also explained residual perceptual deficits at retrained locations. These findings were confirmed with perceptual template model analysis, which further revealed that the major residual deficits between retrained and intact field locations could be explained by differences in internal additive noise. There were no significant differences in multiplicative noise or the ability to process external noise. Together, these results highlight the critical role of altered internal noise processing in mediating training-induced visual recovery in CB fields, and may explain residual perceptual deficits relative to intact regions of the visual field. PMID:26389544

  14. Extra Corporeal Fixation of Fractured Mandibular Condyle

    PubMed Central

    Shenoy K, Vandana; Kengagsubbiah, Srivatsa; V, Sathyabhama; Priya, Vishnu

    2014-01-01

    Condylar fracture is the second most common site in the mandibular fractures. Motor vehicle accident and fall are the major causes of such fractures. Because of the anatomical weakness of the condyle and the shape of the condylar head the antero-medial dislocation of the condyle is common. Open reduction and closed reduction is always debatable. The open reduction will bring back the normal function much earlier than closed reduction. Medially dislocated condylar fracture fragments are always managed with open method. In superior or high condylar fractures,exact reduction with conventional open reduction can be difficult due to the limited surgical and visual fields. In such cases extracorporeal fixation of condyle using vertical ramus osteotomy may be better choice to achieve perfect alignment and absolute maintaince of vertical height of the ramus and facial symmetry. We here present a case of extracorporeal fixation of unilateral left high condylar fracture. PMID:25386546

  15. 76 FR 283 - International Fisheries; Pacific Tuna Fisheries; Vessel Capacity Limit in the Purse Seine Fishery...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-04

    .... SUPPLEMENTARY INFORMATION: On September 3, 2010, NMFS published a proposed rule in the Federal Register (75 FR... the Federal Register (70 FR 19004), which, among other things, established a fleet capacity limit of 8...; Pacific Tuna Fisheries; Vessel Capacity Limit in the Purse Seine Fishery in the Eastern Pacific...

  16. Intramedullary Fixation of Clavicle Fractures: Anatomy, Indications, Advantages, and Disadvantages.

    PubMed

    Eichinger, Josef K; Balog, Todd P; Grassbaugh, Jason A

    2016-07-01

    Historically, management of displaced midshaft clavicle fractures has consisted of nonsurgical treatment. However, recent literature has supported surgical repair of displaced and shortened clavicle fractures. Several options exist for surgical fixation, including plate and intramedullary (IM) fixation. IM fixation has the potential advantages of a smaller incision and decreased dissection and soft-tissue exposure. For the last two decades, the use of Rockwood and Hagie pins represented the most popular form of IM fixation, but concerns exist regarding stability and complications. The use of alternative IM implants, such as Kirschner wires, titanium elastic nails, and cannulated screws, also has been described in limited case series. However, concerns persist regarding the complications associated with the use of these implants, including implant failure, migration, skin complications, and construct stability. Second-generation IM implants have been developed to reduce the limitations of earlier IM devices. Although anatomic and clinical studies have supported IM fixation of midshaft clavicle fractures, further research is necessary to determine the optimal fixation method. PMID:27227985

  17. International Collaboration in Organizations Promoting Geography Education: Exploring Success and Acknowledging Limitations

    ERIC Educational Resources Information Center

    Donert, Karl; Hay, Iain; Theobald, Rebecca; Valiunaite, Vita; Wakefield, Kelly

    2011-01-01

    Effective teaching about many of the geographical issues now confronting Earth and humanity requires collective approaches and shared solutions. It follows, therefore, that there is a need to better understand the basis of and process for sustaining successful international collaboration among geography educators. This paper first examines some of…

  18. The limits of levels: Understanding the International Adult Literacy Surveys (IALS)

    NASA Astrophysics Data System (ADS)

    St. Clair, Ralf

    2012-12-01

    The International Adult Literacy Survey (IALS), an initiative of the Organization for Economic Cooperation and Development (OECD), was carried out in the early to mid-1990s across more than 20 countries. It was followed in the early years of the 21st century by the Adult Literacy and Life Skills (ALL) survey and the Programme for the International Assessment of Adult Competencies (PIAAC, currently in data analysis). This article reviews the philosophical basis, theoretical underpinnings and data analysis of the original and subsequent IALS-based surveys. The purpose is to inform users of the survey data of what the surveys can, and cannot, provide. The author argues that the key use of these surveys is providing insights into population-level distribution of one form of literacy, namely a particular kind of text consumption in a developed society. He also points out the challenges regarding the use of the survey series for making international comparisons, for documenting change over time and for representing broad models of literacy. The tendency to use the survey findings for these uses is considered by the author as a misuse of the data, which leaves the potential of the IALS surveys to provide insights into the effectiveness and equity of different educational systems largely untapped.

  19. Molecular Biology of Nitrogen Fixation

    ERIC Educational Resources Information Center

    Shanmugam, K. T.; Valentine, Raymond C.

    1975-01-01

    Reports that as a result of our increasing knowledge of the molecular biology of nitrogen fixation it might eventually be possible to increase the biological production of nitrogenous fertilizer from atmospheric nitrogen. (GS)

  20. 75 FR 54078 - International Fisheries; Pacific Tuna Fisheries; Vessel Capacity Limit in the Purse Seine Fishery...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-03

    ... April 12, 2005, a final rule was published in the Federal Register (70 FR 19004), which, among other... FR 61046, November 23, 2009). NMFS initially considered including a provision that would rank purse...; Pacific Tuna Fisheries; Vessel Capacity Limit in the Purse Seine Fishery in the Eastern Pacific...

  1. The internal disruption as hard Magnetohydrodynamic limit of 1/2 sawtooth like activity in large helical device

    SciTech Connect

    Varela, J.; Watanabe, K. Y.; Ohdachi, S.

    2012-08-15

    Large helical device (LHD) inward-shifted configurations are unstable to resistive MHD pressure-gradient-driven modes. Sawtooth like activity was observed during LHD operation. The main drivers are the unstable modes 1/2 and 1/3 in the middle and inner plasma region which limit the plasma confinement efficiency of LHD advanced operation scenarios. The aim of the present research is to study the hard MHD limit of 1/2 sawtooth like activity, not observed yet in LHD operation, and to predict its effects on the device performance. Previous investigations pointed out this system relaxation can be an internal disruption [J. Varela et al., 'Internal disruptions and sawtooth like activity in LHD,' 38th EPS Conference on Plasma Physics (2011), P5.077]. In the present work, we simulate an internal disruption; we study the equilibria properties before and after the disruptive process, its effects on the plasma confinement efficiency during each disruptive phase, the relation between the n/m = 1/2 hard MHD events and the soft MHD events, and how to avoid or reduce their adverse effects. The simulation conclusions point out that the large stochastic region in the middle plasma strongly deforms and tears the flux surfaces when the pressure gradient increases above the hard MHD limit. If the instability reaches the inner plasma, the iota profiles will be perturbed near the plasma core and three magnetic islands can appear near the magnetic axis. If the instability is strong enough to link the stochastic regions in the middle plasma (around the half minor radius {rho}) and the plasma core ({rho}<0.25), an internal disruption is driven.

  2. Innovative strategies for transforming internal medicine residency training in resource-limited settings: the Mozambique experience.

    PubMed

    Mocumbi, Ana Olga; Carrilho, Carla; Aronoff-Spencer, Eliah; Funzamo, Carlos; Patel, Sam; Preziosi, Michael; Lederer, Philip; Tilghman, Winston; Benson, Constance A; Badaró, Roberto; Nguenha, A; Schooley, Robert T; Noormahomed, Emília V

    2014-08-01

    With approximately 4 physicians per 100,000 inhabitants, Mozambique faces one of the most severe health care provider shortages in Sub-Saharan Africa. The lack of sufficient well-trained medical school faculty is one of Mozambique's major barrier to producing new physicians annually. A partnership between the Universidade Eduardo Mondlane and the University of California, San Diego, has addressed this challenge with support from the Medical Education Partnership Initiative. After an initial needs assessment involving questionnaires and focus groups of residents, and working with key members from the Ministry of Health, the Medical Council, and Maputo Central Hospital, a set of interventions was designed. The hospital's internal medicine residency program was chosen as the focus for the plan. Interventions included curriculum design, new teaching methodologies, investment in an informatics infrastructure for access to digital references, building capacity to support clinical research, and providing financial incentives to retain junior faculty. The number of candidates entering the internal medicine residency program has increased, and detailed monitoring and evaluation is measuring the impact of these changes on the quality of training. These changes are expected to improve the long-term quality of postgraduate training in general through dissemination to other departments. They also have the potential to facilitate equitable distribution of specialists nationwide by expanding postgraduate training to other hospitals and universities. PMID:25072585

  3. Study of Internal Dump Stability of Dudhichua Open Cast Project, Northern Coalfields Limited, India

    NASA Astrophysics Data System (ADS)

    Sengupta, S.; Roy, I.

    2015-04-01

    Dudhichua Open Cast Project is one of the prestigious projects of Northern Coalfields Limited, India; with total mineable coal reserves of approximately 400 million tonnes and corresponding 1,700 million m3 volume of waste rock i.e. overburden material. Accommodating this waste dump masses in the limited space of the de-coaled portion of the quarry is considered as one of the major challenges to the mine operators. It has been reported that this mine is facing frequent slope failures of waste rock dumps which is of great concern to the mine management in view of unsafe working condition. To tackle the above problem, a detailed investigation was carried out to propose a stable dump profile which will cater to the land economics and safety aspects of the mine. A detailed investigation along with recommendation of optimum design for dragline dump profile along with shovel-dumper-dump profile is presented in this paper.

  4. Failed Fixation in Atrophic Mandibular Fractures: The Case against Miniplates.

    PubMed

    Madsen, Matthew J; Kushner, George M; Alpert, Brian

    2011-09-01

    Despite advances in the treatment of the fractured atrophic edentulous mandible, treatment continues to be difficult. Patient management is more complicated due to patients often being elderly with more complex medical problems. Rigid internal fixation has greatly improved outcomes with shorter treatment times, yet a consensus has yet to be reached regarding which method yields the most predictable results. Options include using small miniplates to larger reconstruction plates. Although each method has advantages, we present our experience with retreatment of failed miniplate fixation using load-bearing reconstruction plates of fractured atrophic edentulous mandibles. PMID:22942943

  5. Fixation duration surpasses pupil size as a measure of memory load in free viewing

    PubMed Central

    Meghanathan, Radha Nila; van Leeuwen, Cees; Nikolaev, Andrey R.

    2015-01-01

    Oculomotor behavior reveals, not only the acquisition of visual information at fixation, but also the accumulation of information in memory across subsequent fixations. Two candidate measures were considered as indicators of such dynamic visual memory load: fixation duration and pupil size. While recording these measures, we displayed an arrangement of 3, 4 or 5 targets among distractors. Both occurred in various orientations. Participants searched for targets and reported whether in a subsequent display one of them had changed orientation. We determined to what extent fixation duration and pupil size indicate dynamic memory load, as a function of the number of targets fixated during the search. We found that fixation duration reflects the number of targets, both when this number is within and above the limit of working memory capacity. Pupil size reflects the number of targets only when it exceeds the capacity limit. Moreover, the duration of fixations on successive targets but not on distractors increases whereas pupil size does not. The increase in fixation duration with number of targets both within and above working memory capacity suggests that in free viewing fixation duration is sensitive to actual memory load as well as to processing load, whereas pupil size is indicative of processing load only. Two alternative models relating visual attention and working memory are considered relevant to these results. We discuss the results as supportive of a model which involves a temporary buffer in the interaction of attention and working memory. PMID:25653606

  6. Visual fixation in the vegetative state: an observational case series PET study

    PubMed Central

    2010-01-01

    Background Assessment of visual fixation is commonly used in the clinical examination of patients with disorders of consciousness. However, different international guidelines seem to disagree whether fixation is compatible with the diagnosis of the vegetative state (i.e., represents "automatic" subcortical processing) or is a sufficient sign of consciousness and higher order cortical processing. Methods We here studied cerebral metabolism in ten patients with chronic post-anoxic encephalopathy and 39 age-matched healthy controls. Five patients were in a vegetative state (without fixation) and five presented visual fixation but otherwise showed all criteria typical of the vegetative state. Patients were matched for age, etiology and time since insult and were followed by repeated Coma Recovery Scale-Revised (CRS-R) assessments for at least 1 year. Sustained visual fixation was considered as present when the eyes refixated a moving target for more than 2 seconds as defined by CRS-R criteria. Results Patients without fixation showed metabolic dysfunction in a widespread fronto-parietal cortical network (with only sparing of the brainstem and cerebellum) which was not different from the brain function seen in patients with visual fixation. Cortico-cortical functional connectivity with visual cortex showed no difference between both patient groups. Recovery rates did not differ between patients without or with fixation (none of the patients showed good outcome). Conclusions Our findings suggest that sustained visual fixation in (non-traumatic) disorders of consciousness does not necessarily reflect consciousness and higher order cortical brain function. PMID:20504324

  7. The Compressible Viscous Surface-Internal Wave Problem: Stability and Vanishing Surface Tension Limit

    NASA Astrophysics Data System (ADS)

    Jang, Juhi; Tice, Ian; Wang, Yanjin

    2016-05-01

    This paper concerns the dynamics of two layers of compressible, barotropic, viscous fluid lying atop one another. The lower fluid is bounded below by a rigid bottom, and the upper fluid is bounded above by a trivial fluid of constant pressure. This is a free boundary problem: the interfaces between the fluids and above the upper fluid are free to move. The fluids are acted on by gravity in the bulk, and at the free interfaces we consider both the case of surface tension and the case of no surface forces. We establish a sharp nonlinear global-in-time stability criterion and give the explicit decay rates to the equilibrium. When the upper fluid is heavier than the lower fluid along the equilibrium interface, we characterize the set of surface tension values in which the equilibrium is nonlinearly stable. Remarkably, this set is non-empty, i.e., sufficiently large surface tension can prevent the onset of the Rayleigh-Taylor instability. When the lower fluid is heavier than the upper fluid, we show that the equilibrium is stable for all non-negative surface tensions and we establish the zero surface tension limit.

  8. Arthroscopy Assisted Percutaneous Fixation of Ideberg Type Iii Glenoid Fractures

    PubMed Central

    Acharya, Prashant; Arora, Bakul; Pinto, Nelson

    2015-01-01

    Introduction: Intra-articular glenoid fractures are extremely rare and may be associated with other injuries. Traditionally open reduction and internal fixation has been recommended in displaced intra-articular glenoid fractures. However open reduction is difficult and it may not be possible to address the associated intra-articular soft tissue injuries. A few reports of arthroscopic assisted fixation of these fractures have been recently published. We are reporting a case of Ideberg type 3 glenoid fracture and its treatment. Case Report: We are presenting our case where a 52 year old man presented with Type 3 intra-articular glenoid fracture. The fracture was fixed percutaneously under simultaneous arthroscopic and fluoroscopic guidance. Conclusion: Intra-articular glenoid fractures are uncommon and difficult to treat. Arthroscopy assisted percutaneous fixation technique can be a valuable adjunct for the surgeon in dealing with not only the fracture but also the associated soft-tissue injuries. PMID:27299041

  9. Internal photomechanical fracture of spatially limited absorbers irradiated by short laser pulses

    NASA Astrophysics Data System (ADS)

    Paltauf, Guenther; Schmidt-Kloiber, Heinz

    1998-05-01

    A photomechanical damage mechanism in abosrbing regions or particles surrounded by a non-abosrbing medium after irradiation with a short laser pulse is investigated experimentally and theoretically. In tissue, such absorbers are for example melanosomes, blood vessels or tatoo pigments. It follows from theoretical considerations that the photoacoustic wave caused by irradiation of a spatially limited volume contains both compressive and tensile stress. Experiments were performed to test whether these tensile stresses cause cavitation in absorbers of spherical or cylindrical shape. High-speed video images of liquid spheres or gelatin cylinders (diameters 200 to 300 micrometer) suspended in oil showed that cavitation occurs at the center of the spheres or on the cylinder axis, respectively, shortly after irradiation with a light pulse (6 ns duration) from an optical parametric oscillator. The cavitation effect was observed at maximum temperatures below and above the boiling point and at ratios of the absorber size on the absorption length larger and smaller than one. The experimental findings are supported by theoretical calculations, from which strong tensile stresses are predicted in the interior of the absorbers, even if the values of acoustic impedance inside and outside the absorbing volume are equal. The reported effect is believed to cause damage to absorbers if the pulse duration is short enough to provide stress confinement, that is if the time an acoustic wave needs to cross the abosrbing region is longer than the pulse duration. For small absorbers such as melanosomes with a size of about 1 micrometer this requires a laser pulse duration in the picosecond regime.

  10. Intermittent internal fixation with a locking plate to preserve epiphyseal growth function during limb-salvage surgery in a child with osteosarcoma of the distal femur: a case report.

    PubMed

    Mei, Jiong; Ni, Ming; Jia, Guang-Yao; Chen, Yan-Xi; Zhu, Xiao-Zhong

    2015-05-01

    Limb shortening is a problem associated with surgery for osteosarcoma of the lower extremity in adolescents, as the tumors frequently occur near the epiphysis. Herein we report the use of a less invasive stabilization system (LISS) and an intermittent fixation method to preserve the growth function of epiphysis in an 11-year-old patient with an osteosarcoma of the distal femur.The 11-year-old male presented with left knee enlargement and pain for 2 weeks, and magnetic resonance imaging (MRI) and biopsy were consistent with osteosarcoma of the left distal femur. After preoperative chemotherapy, en bloc tumor resection was performed with margins based on MRI findings preserving the epiphyseal growth plate, the tumor cavity was filled with inactivated bone and bone cement, and a LISS was used to stabilize the femur. Aggressive postoperative chemotherapy was given. Approximately 105 weeks after surgery radiography showed that the distal end of the plate had moved superior to the epiphysis along with bone growth. Locking screws were placed in the distal part of the LISS plate to stabilize the re-implanted bone, and external fixation was not needed.The patient was able to walk with the crutches 1 week postoperatively, and bear weight on the extremity 6 weeks postoperatively. At 6 years after surgery, the patient's height had increased 52 cm, shortening of the affected limb was only 1 cm, and the circumference of the affected limb was 2 cm smaller than that of the contralateral limb. There was no significant discomfort in the affected limb, and there was no gait abnormality. The patient could jump and run, and could participate in sports including basketball and badminton to the same degree as his peers.In summary, the novel method of bone reconstruction and fixation provided good results in a child with an osteosarcoma of the distal femur. This fixation method preserves the osteogenic function of the epiphysis and restored bone integrity simultaneously, and

  11. The International Limits and Population at Risk of Plasmodium vivax Transmission in 2009

    PubMed Central

    Guerra, Carlos A.; Howes, Rosalind E.; Patil, Anand P.; Gething, Peter W.; Van Boeckel, Thomas P.; Temperley, William H.; Kabaria, Caroline W.; Tatem, Andrew J.; Manh, Bui H.; Elyazar, Iqbal R. F.; Baird, J. Kevin; Snow, Robert W.; Hay, Simon I.

    2010-01-01

    development and control, P. vivax remains more widely distributed than P. falciparum and is a potential cause of morbidity and mortality amongst the 2.85 billion people living at risk of infection, the majority of whom are in the tropical belt of CSE Asia. The probability of infection is reduced massively across Africa by the frequency of the Duffy negative trait, but transmission does occur on the continent and is a concern for Duffy positive locals and travellers. The final map provides the spatial limits on which the endemicity of P. vivax transmission can be mapped to support future cartographic-based burden estimations. PMID:20689816

  12. Ankle Injury Management (AIM): design of a pragmatic multi-centre equivalence randomised controlled trial comparing Close Contact Casting (CCC) to Open surgical Reduction and Internal Fixation (ORIF) in the treatment of unstable ankle fractures in patients over 60 years

    PubMed Central

    2014-01-01

    Background Ankle fractures account for 9% of all fractures with a quarter of these occurring in adults over 60 years. The short term disability and long-term consequences of this injury can be considerable. Current opinion favours open reduction and internal fixation (ORIF) over non-operative treatment (fracture manipulation and the application of a standard moulded cast) for older people. Both techniques are associated with complications but the limited published research indicates higher complication rates of fracture malunion (poor position at healing) with casting. The aim of this study is to compare ORIF with a modification of existing casting techniques, Close Contact Casting (CCC). We propose that CCC may offer an equivalent functional outcome to ORIF and avoid the risks associated with surgery. Methods/Design This study is a pragmatic multi-centre equivalence randomised controlled trial. 620 participants will be randomised to receive ORIF or CCC after sustaining an isolated displaced unstable ankle fracture. Participants will be recruited from a minimum of 20 National Health Service (NHS) acute hospitals throughout England and Wales. Participants will be aged over 60 years and be ambulatory prior to injury. Follow-up will be at six weeks and six months after randomisation. The primary outcome is the Olerud & Molander Ankle Score, a functional patient reported outcome measure, at 6 months. Follow-up will also include assessments of mobility, ankle range of movement, health related quality of life and complications. The six-month follow-up will be conducted face-to-face by an assessor blinded to the allocated intervention. A parallel economic evaluation will consider both a health service and a broader societal perspective including the individual and their family. In order to explore patient experience of their treatment and recovery, a purposive sample of 40 patients will also be interviewed using a semi-structured interview schedule between 6-10

  13. Missing nitrogen fixation in the Benguela region

    NASA Astrophysics Data System (ADS)

    Wasmund, Norbert; Struck, Ulrich; Hansen, Anja; Flohr, Anita; Nausch, Günther; Grüttmüller, Annett; Voss, Maren

    2015-12-01

    Opposing opinions on the importance of nitrogen fixation in the northern Benguela upwelling region provoked us to investigate the magnitude of nitrogen fixation in front of northern Namibia and southern Angola. Measurements of nitrogen fixation rates using the 15N method at 66 stations during seven cruises from 2008 to 2014 showed that, in general, the 15N content in the biomass did not increase after tracer incubation with 15N2, indicating that no nitrogen fixation occurred. Correspondingly, the filamentous nitrogen-fixing cyanobacterium Trichodesmium was almost not present. The abundant picocyanobacteria did obviously not perform nitrogen fixation to a significant degree. The artificial improvement of conditions for nitrogen fixation in mesocosm experiments, including phosphate and iron additions and a warmer temperature, failed to induce nitrogen fixation. A plausible explanation of these findings is a lack of conditioned cells for nitrogen fixation in the Benguela region.

  14. First metatarsophalangeal joint arthrodesis: current fixation options.

    PubMed

    Moon, Jared L; McGlamry, Michael C

    2011-04-01

    This article reviews the current literature on first metatarsophalangeal joint arthrodesis rates using various forms of fixation, as well as reviewing biomechanical studies comparing the strengths of the different fixation options that are available. PMID:21669346

  15. Complement fixation test to C. burnetii

    MedlinePlus

    ... ency/article/003520.htm Complement fixation test to C burnetii To use the sharing features on this ... JavaScript. The complement fixation test to Coxiella burnetii ( C burnetti ) is a blood test that checks for ...

  16. The use of silk-based devices for fracture fixation

    NASA Astrophysics Data System (ADS)

    Perrone, Gabriel S.; Leisk, Gary G.; Lo, Tim J.; Moreau, Jodie E.; Haas, Dylan S.; Papenburg, Bernke J.; Golden, Ethan B.; Partlow, Benjamin P.; Fox, Sharon E.; Ibrahim, Ahmed M. S.; Lin, Samuel J.; Kaplan, David L.

    2014-03-01

    Metallic fixation systems are currently the gold standard for fracture fixation but have problems including stress shielding, palpability and temperature sensitivity. Recently, resorbable systems have gained interest because they avoid removal and may improve bone remodelling due to the lack of stress shielding. However, their use is limited to paediatric craniofacial procedures mainly due to the laborious implantation requirements. Here we prepare and characterize a new family of resorbable screws prepared from silk fibroin for craniofacial fracture repair. In vivo assessment in rat femurs shows the screws to be self-tapping, remain fixed in the bone for 4 and 8 weeks, exhibit biocompatibility and promote bone remodelling. The silk-based devices compare favourably with current poly-lactic-co-glycolic acid fixation systems, however, silk-based devices offer numerous advantages including ease of implantation, conformal fit to the repair site, sterilization by autoclaving and minimal inflammatory response.

  17. Fixation properties of subdivided populations with balancing selection.

    PubMed

    Lombardo, Pierangelo; Gambassi, Andrea; Dall'Asta, Luca

    2015-03-01

    In subdivided populations, migration acts together with selection and genetic drift and determines their evolution. Building upon a recently proposed method, which hinges on the emergence of a time scale separation between local and global dynamics, we study the fixation properties of subdivided populations in the presence of balancing selection. The approximation implied by the method is accurate when the effective selection strength is small and the number of subpopulations is large. In particular, it predicts a phase transition between species coexistence and biodiversity loss in the infinite-size limit and, in finite populations, a nonmonotonic dependence of the mean fixation time on the migration rate. In order to investigate the fixation properties of the subdivided population for stronger selection, we introduce an effective coarser description of the dynamics in terms of a voter model with intermediate states, which highlights the basic mechanisms driving the evolutionary process. PMID:25871077

  18. Weakly Supervised Human Fixations Prediction.

    PubMed

    Zhang, Luming; Li, Xuelong; Nie, Liqiang; Yang, Yi; Xia, Yingjie

    2016-01-01

    Automatically predicting human eye fixations is a useful technique that can facilitate many multimedia applications, e.g., image retrieval, action recognition, and photo retargeting. Conventional approaches are frustrated by two drawbacks. First, psychophysical experiments show that an object-level interpretation of scenes influences eye movements significantly. Most of the existing saliency models rely on object detectors, and therefore, only a few prespecified categories can be discovered. Second, the relative displacement of objects influences their saliency remarkably, but current models cannot describe them explicitly. To solve these problems, this paper proposes weakly supervised fixations prediction, which leverages image labels to improve accuracy of human fixations prediction. The proposed model hierarchically discovers objects as well as their spatial configurations. Starting from the raw image pixels, we sample superpixels in an image, thereby seamless object descriptors termed object-level graphlets (oGLs) are generated by random walking on the superpixel mosaic. Then, a manifold embedding algorithm is proposed to encode image labels into oGLs, and the response map of each prespecified object is computed accordingly. On the basis of the object-level response map, we propose spatial-level graphlets (sGLs) to model the relative positions among objects. Afterward, eye tracking data is employed to integrate these sGLs for predicting human eye fixations. Thorough experiment results demonstrate the advantage of the proposed method over the state-of-the-art. PMID:26168451

  19. Understanding Nitrogen Fixation

    SciTech Connect

    Paul J. Chirik

    2012-05-25

    synthesis of ammonia, NH{sub 3}, from its elements, H{sub 2} and N{sub 2}, via the venerable Haber-Bosch process is one of the most significant technological achievements of the past century. Our research program seeks to discover new transition metal reagents and catalysts to disrupt the strong N {triple_bond} N bond in N{sub 2} and create new, fundamental chemical linkages for the construction of molecules with application as fuels, fertilizers and fine chemicals. With DOE support, our group has discovered a mild method for ammonia synthesis in solution as well as new methods for the construction of nitrogen-carbon bonds directly from N{sub 2}. Ideally these achievements will evolve into more efficient nitrogen fixation schemes that circumvent the high energy demands of industrial ammonia synthesis. Industrially, atmospheric nitrogen enters the synthetic cycle by the well-established Haber-Bosch process whereby N{sub 2} is hydrogenated to ammonia at high temperature and pressure. The commercialization of this reaction represents one of the greatest technological achievements of the 20th century as Haber-Bosch ammonia is responsible for supporting approximately 50% of the world's population and serves as the source of half of the nitrogen in the human body. The extreme reaction conditions required for an economical process have significant energy consequences, consuming 1% of the world's energy supply mostly in the form of pollution-intensive coal. Moreover, industrial H{sub 2} synthesis via the water gas shift reaction and the steam reforming of methane is fossil fuel intensive and produces CO{sub 2} as a byproduct. New synthetic methods that promote this thermodynamically favored transformation ({Delta}G{sup o} = -4.1 kcal/mol) under milder conditions or completely obviate it are therefore desirable. Most nitrogen-containing organic molecules are derived from ammonia (and hence rely on the Haber-Bosch and H{sub 2} synthesis processes) and direct synthesis from

  20. Limited internal radiation exposure associated with resettlements to a radiation-contaminated homeland after the Fukushima Daiichi nuclear disaster.

    PubMed

    Tsubokura, Masaharu; Kato, Shigeaki; Nihei, Masahiko; Sakuma, Yu; Furutani, Tomoyuki; Uehara, Keisuke; Sugimoto, Amina; Nomura, Shuhei; Hayano, Ryugo; Kami, Masahiro; Watanobe, Hajime; Endo, Yukou

    2013-01-01

    Resettlement to their radiation-contaminated hometown could be an option for people displaced at the time of a nuclear disaster; however, little information is available on the safety implications of these resettlement programs. Kawauchi village, located 12-30 km southwest of the Fukushima Daiichi nuclear power plant, was one of the 11 municipalities where mandatory evacuation was ordered by the central government. This village was also the first municipality to organize the return of the villagers. To assess the validity of the Kawauchi villagers' resettlement program, the levels of internal Cesium (Cs) exposures were comparatively measured in returnees, commuters, and non-returnees among the Kawauchi villagers using a whole body counter. Of 149 individuals, 5 villagers had traceable levels of Cs exposure; the median detected level was 333 Bq/body (range, 309-1050 Bq/kg), and 5.3 Bq/kg (range, 5.1-18.2 Bq/kg). Median annual effective doses of villagers with traceable Cs were 1.1 x 10(-2) mSv/y (range, 1.0 x 10(-2)-4.1 x 10(-2) mSv/y). Although returnees had higher chances of consuming locally produced vegetables, Cochran-Mantel-Haenszel test showed that their level of internal radiation exposure was not significantly higher than that in the other 2 groups (p=0.643). The present findings in Kawauchi village imply that it is possible to maintain internal radiation exposure at very low levels even in a highly radiation-contaminated region at the time of a nuclear disaster. Moreover, the risks for internal radiation exposure could be limited with a strict food control intervention after resettlement to the radiation-contaminated village. It is crucial to establish an adequate number of radio-contaminated testing sites within the village, to provide immediate test result feedback to the villagers, and to provide education regarding the importance of re-testing in reducing the risk of high internal radiation exposure. PMID:24312602

  1. Limited Internal Radiation Exposure Associated with Resettlements to a Radiation-Contaminated Homeland after the Fukushima Daiichi Nuclear Disaster

    PubMed Central

    Tsubokura, Masaharu; Kato, Shigeaki; Nihei, Masahiko; Sakuma, Yu; Furutani, Tomoyuki; Uehara, Keisuke; Sugimoto, Amina; Nomura, Shuhei; Hayano, Ryugo; Kami, Masahiro; Watanobe, Hajime; Endo, Yukou

    2013-01-01

    Resettlement to their radiation-contaminated hometown could be an option for people displaced at the time of a nuclear disaster; however, little information is available on the safety implications of these resettlement programs. Kawauchi village, located 12–30 km southwest of the Fukushima Daiichi nuclear power plant, was one of the 11 municipalities where mandatory evacuation was ordered by the central government. This village was also the first municipality to organize the return of the villagers. To assess the validity of the Kawauchi villagers’ resettlement program, the levels of internal Cesium (Cs) exposures were comparatively measured in returnees, commuters, and non-returnees among the Kawauchi villagers using a whole body counter. Of 149 individuals, 5 villagers had traceable levels of Cs exposure; the median detected level was 333 Bq/body (range, 309–1050 Bq/kg), and 5.3 Bq/kg (range, 5.1–18.2 Bq/kg). Median annual effective doses of villagers with traceable Cs were 1.1 x 10-2 mSv/y (range, 1.0 x 10-2-4.1 x 10-2 mSv/y). Although returnees had higher chances of consuming locally produced vegetables, Cochran-Mantel-Haenszel test showed that their level of internal radiation exposure was not significantly higher than that in the other 2 groups (p=0.643). The present findings in Kawauchi village imply that it is possible to maintain internal radiation exposure at very low levels even in a highly radiation-contaminated region at the time of a nuclear disaster. Moreover, the risks for internal radiation exposure could be limited with a strict food control intervention after resettlement to the radiation-contaminated village. It is crucial to establish an adequate number of radio-contaminated testing sites within the village, to provide immediate test result feedback to the villagers, and to provide education regarding the importance of re-testing in reducing the risk of high internal radiation exposure. PMID:24312602

  2. Options for acetabular fixation surfaces.

    PubMed

    Klika, Alison K; Murray, Trevor G; Darwiche, Hussein; Barsoum, Wael K

    2007-01-01

    Aseptic loosening is the most common cause for revision total hip arthroplasty (THA). Due to poor long-term results with cemented acetabular components, cementless implants that rely on biologic fixation became popular in the United States for both primary and revision procedures in the early 1980s. Cementless acetabular components used in THA have been reported to have superior radiographic performance compared with cemented fixation, although the optimal method of acetabular fixation remains controversial. Cementless acetabular components require initial implant stability to allow for bone ingrowth and remodeling into the acetabular shell, providing long-term durability of the prosthesis. Many improved implant materials are available to facilitate bone growth and remodeling, including the 3 most common surface treatments; fibermesh, sintered beads, and plasma spray coatings. Recently added to these are porous metal surfaces, which have increased porosity and optimal pore sizes when compared with titanium fibermesh. The most studied of these materials is the titanium fibermesh fixation surface, which has demonstrated a mechanical failure rate of 1% at 10 to 15 years. This technology utilizes the diffusion bonding process to attach fiber metal pads to a titanium substrate using heat and pressure. The sintered bead fixation surface offers a porous coating of various sizes of spherical beads, achieved by the sintering process, and has been shown to provide long-term fixation. While there are less long-term published data regarding the titanium plasma spray surface, its early results have provided evidence of its durability, even in the face of significant osteolysis. The most recently added alternative fixation surface is porous tantalum metal, which offers potentially greater bone ingrowth and bone graft incorporation due to its high porosity (80%) and low modulus of elasticity (3 MPa). Porous tantalum implants have shown early favorable clinical results and have

  3. Tissue fixation and the effect of molecular fixatives on downstream staining procedures.

    PubMed

    Howat, William J; Wilson, Beverley A

    2014-11-01

    It is impossible to underplay the importance of fixation in histopathology. Whether the scientist is interested in the extraction of information on lipids, proteins, RNA or DNA, fixation is critical to this extraction. This review aims to give a brief overview of the current "state of play" in fixation and focus on the effect fixation, and particularly the effect of the newer brand of "molecular fixatives" have on morphology, histochemistry, immunohistochemistry and RNA/DNA analysis. A methodology incorporating the creation of a fixation tissue microarray for the study of the effect of fixation on histochemistry is detailed. PMID:24561827

  4. Revisiting trends in wetness and dryness in the presence of internal climate variability and water limitations over land

    NASA Astrophysics Data System (ADS)

    Kumar, Sanjiv; Allan, Richard P.; Zwiers, Francis; Lawrence, David M.; Dirmeyer, Paul A.

    2015-12-01

    A theoretically expected consequence of the intensification of the hydrological cycle under global warming is that on average, wet regions get wetter and dry regions get drier (WWDD). Recent studies, however, have found significant discrepancies between the expected pattern of change and observed changes over land. We assess the WWDD theory in four climate models. We find that the reported discrepancy can be traced to two main issues: (1) unforced internal climate variability strongly affects local wetness and dryness trends and can obscure underlying agreement with WWDD, and (2) dry land regions are not constrained to become drier by enhanced moisture divergence since evaporation cannot exceed precipitation over multiannual time scales. Over land, where the available water does not limit evaporation, a "wet gets wetter" signal predominates. On seasonal time scales, where evaporation can exceed precipitation, trends in wet season becoming wetter and dry season becoming drier are also found.

  5. Limitations of Condensed Teaching Strategies to Develop Hand-Held Cardiac Ultrasonography Skills in Internal Medicine Residents.

    PubMed

    Wilkinson, Jeffrey S; Barake, Walid; Smith, Chris; Thakrar, Amar; Johri, Amer M

    2016-08-01

    Advances in ultrasonographic technology have allowed for hand-held cardiac ultrasonography (HHCU) units that fit into a physician's laboratory coat. Recently, studies to educate internal medicine residents have shown promise. The optimal duration and methodology for teaching HHCU skills has not been established. Over a 1-year period, internal medicine residents were recruited during their cardiology ward rotation into a single-centre nonblinded randomized trial. The 2 condensed teaching strategies were (1) a conventional ward-based program and (2) a technology-driven simulation-based strategy. Outcomes were evaluated by (1) an objective structured clinical examination (OSCE) to evaluate interpretation ability (assessing both type I and type II error rates) and (2) demonstration of HHCU skills graded by 2 level III echocardiographers. Twenty-four internal medicine residents were randomized. After teaching, the conventional teaching group had a significant absolute increase in the ability to make a singular correct diagnosis (20%; P < 0.001). In the technology arm, making a singular correct diagnosis increased 24% from baseline (P = 0.001). Interpretation skill was not significantly different between groups. The false-positive rate increased by an absolute 14% and 17% in the conventional and technology groups, respectively (P = 0.079 and P = 0.008). Our findings suggest that HHCU interpretation skills improve after either a conventional ward-based or a technology-driven approach. However, our study emphasizes the important limitations of both teaching programs, because we detected a trend toward an increase in the false-positive rate after both approaches. This suggests that a short duration of training may not be sufficient for HHCU to be performed in a safe manner. PMID:26860772

  6. Percutaneous Screw Fixation of Crescent Fracture-Dislocation of the Sacroiliac Joint.

    PubMed

    Shui, Xiaolong; Ying, Xiaozhou; Mao, Chuanwan; Feng, Yongzeng; Chen, Linwei; Kong, Jianzhong; Guo, Xiaoshan; Wang, Gang

    2015-11-01

    Crescent fracture-dislocation of the sacroiliac joint (CFDSIJ) is a type of lateral compression pelvic injury associated with instability. Open reduction and internal fixation is a traditional treatment of CFDSIJ. However, a minimally invasive method has never been reported. The purpose of this study was to assess the outcome of closed reduction and percutaneous fixation for different types of CFDSIJ and present their clinical outcome. The authors reviewed 117 patients diagnosed with CFDSIJ between July 2003 and July 2013. Closed reduction and percutaneous fixation was performed in 73 patients. Treatment selection was based on Day's fracture classification. For type I fractures, fixation perpendicular to the fracture line were performed. For type II fractures, crossed fixation was performed. For type III fractures, fixation was performed with iliosacral screws. Forty-four patients were treated by open reduction and plate fixation. Demographics, fracture pattern distribution, blood loss, incision lengths, revision surgeries, radiological results, and functional scores were compared. All 117 patients were followed for more than 6 months (mean, 14 months [range, 6-24 months]). Blood loss, extensive exposure, duration of posterior ring surgery, duration of hospital stay, and infection rates were lower in the closed group (P<.01). Patients in the closed group achieved better functional performance (P<.01). There were no significant differences in reduction quality (P=.32), revision surgery rates (P=.27), and iatrogenic neurologic injuries (P=.2) between the 2 groups. The authors' results indicate that closed reduction and percutaneous fixation is a safe and effective surgical method for CFDSIJ. PMID:26558677

  7. Serum albumin and fixation failure with cannulated hip screws in undisplaced intracapsular femoral neck fracture.

    PubMed

    Riaz, O; Arshad, R; Nisar, S; Vanker, R

    2016-07-01

    Introduction Internal fixation of undisplaced intracapsular femoral neck fractures with cannulated hip screws is a widely accepted surgical technique, despite reported failure rates of 12%-19%. This study determined whether preoperative serum albumin levels are linked to fixation failure. Methods We retrospectively reviewed 251 consecutive undisplaced intracapsular femoral neck fracture patients treated with cannulated hip screws in a district general hospital. Preoperative albumin levels were measured, and the fixation technique, classification and posterior tilt on radiography assessed. Fixation failure was defined as a screw cut, avascular necrosis (AVN) or non-union. Results Of the patients, 185 were female and 66 male. The mean age was 77 years (range 60-101 years). Thirty seven (15%) patients had fixation failure: 10 (4%) due to AVN; 12 (5%) due to non-union; and 15 (6%) due to fixation collapse. Low serum albumin levels were significantly associated with failure (p=0.01), whereas gender (p=0.56), operated side (p=0.62), age (p=0.34) and screw configuration (p=0.42) were not. A posterior tilt angle greater than 20° on lateral radiography significantly predicted failure (p=0.002). Conclusions Preoperative serum albumin is an independent predictor of cannulated hip screw fixation failure in undisplaced femoral neck fractures. Nutritional status should therefore be considered when deciding between surgical fixation and arthroplasty to avoid the possibility of revision surgery, along with an increased risk of morbidity and mortality. PMID:27055409

  8. Conversion efficiency limits and bandgap designs for multi-junction solar cells with internal radiative efficiencies below unity.

    PubMed

    Zhu, Lin; Mochizuki, Toshimitsu; Yoshita, Masahiro; Chen, Shaoqiang; Kim, Changsu; Akiyama, Hidefumi; Kanemitsu, Yoshihiko

    2016-05-16

    We calculated the conversion-efficiency limit ηsc and the optimized subcell bandgap energies of 1 to 5 junction solar cells without and with intermediate reflectors under 1-sun AM1.5G and 1000-sun AM1.5D irradiations, particularly including the impact of internal radiative efficiency (ηint) below unity for realistic subcell materials on the basis of an extended detailed-balance theory. We found that the conversion-efficiency limit ηsc significantly drops when the geometric mean ηint* of all subcell ηint in the stack reduces from 1 to 0.1, and that ηsc degrades linearly to logηint* for ηint* below 0.1. For ηint*<0.1 differences in ηsc due to additional intermediate reflectors became very small if all subcells are optically thick for sun light. We obtained characteristic optimized bandgap energies, which reflect both ηint* decrease and AM1.5 spectral gaps. These results provide realistic efficiency targets and design principles. PMID:27409948

  9. Low rates of nitrogen fixation in eastern tropical South Pacific surface waters.

    PubMed

    Knapp, Angela N; Casciotti, Karen L; Berelson, William M; Prokopenko, Maria G; Capone, Douglas G

    2016-04-19

    An extensive region of the Eastern Tropical South Pacific (ETSP) Ocean has surface waters that are nitrate-poor yet phosphate-rich. It has been proposed that this distribution of surface nutrients provides a geochemical niche favorable for N2fixation, the primary source of nitrogen to the ocean. Here, we present results from two cruises to the ETSP where rates of N2fixation and its contribution to export production were determined with a suite of geochemical and biological measurements. N2fixation was only detectable using nitrogen isotopic mass balances at two of six stations, and rates ranged from 0 to 23 µmol N m(-2)d(-1)based on sediment trap fluxes. Whereas the fractional importance of N2fixation did not change, the N2-fixation rates at these two stations were several-fold higher when scaled to other productivity metrics. Regardless of the choice of productivity metric these N2-fixation rates are low compared with other oligotrophic locations, and the nitrogen isotope budgets indicate that N2fixation supports no more than 20% of export production regionally. Although euphotic zone-integrated short-term N2-fixation rates were higher, up to 100 µmol N m(-2)d(-1), and detected N2fixation at all six stations, studies of nitrogenase gene abundance and expression from the same cruises align with the geochemical data and together indicate that N2fixation is a minor source of new nitrogen to surface waters of the ETSP. This finding is consistent with the hypothesis that, despite a relative abundance of phosphate, iron may limit N2fixation in the ETSP. PMID:26976587

  10. Evolution of the Hoffmann Fixators.

    PubMed

    Seligson, David

    2015-09-01

    Dr. Raoul Hoffmann of Geneva, Switzerland with the collaboration of Henri Jaquet developed the original Hoffmann external fixateur as a system for treating broken bones without necessarily opening a fracture site to reposition the bone ends. This system has evolved to a more flexible, modular concept with input from surgeons and engineers. In this chapter the modifications of the Hoffmann family of fixators are traced and the important steps in the development of the concept and the instrumentation emphasized. PMID:26458297

  11. Fixation strategies for retinal immunohistochemistry.

    PubMed

    Stradleigh, Tyler W; Ishida, Andrew T

    2015-09-01

    Immunohistochemical and ex vivo anatomical studies have provided many glimpses of the variety, distribution, and signaling components of vertebrate retinal neurons. The beauty of numerous images published to date, and the qualitative and quantitative information they provide, indicate that these approaches are fundamentally useful. However, obtaining these images entailed tissue handling and exposure to chemical solutions that differ from normal extracellular fluid in composition, temperature, and osmolarity. Because the differences are large enough to alter intercellular and intracellular signaling in neurons, and because retinae are susceptible to crush, shear, and fray, it is natural to wonder if immunohistochemical and anatomical methods disturb or damage the cells they are designed to examine. Tissue fixation is typically incorporated to guard against this damage and is therefore critically important to the quality and significance of the harvested data. Here, we describe mechanisms of fixation; advantages and disadvantages of using formaldehyde and glutaraldehyde as fixatives during immunohistochemistry; and modifications of widely used protocols that have recently been found to improve cell shape preservation and immunostaining patterns, especially in proximal retinal neurons. PMID:25892361

  12. Fixation Strategies For Retinal Immunohistochemistry

    PubMed Central

    Stradleigh, Tyler W.; Ishida, Andrew T.

    2015-01-01

    Immunohistochemical and ex vivo anatomical studies have provided many glimpses of the variety, distribution, and signaling components of vertebrate retinal neurons. The beauty of numerous images published to date, and the qualitative and quantitative information they provide, indicate that these approaches are fundamentally useful. However, obtaining these images entailed tissue handling and exposure to chemical solutions that differ from normal extracellular fluid in composition, temperature, and osmolarity. Because the differences are large enough to alter intercellular and intracellular signaling in neurons, and because retinae are susceptible to crush, shear, and fray, it is natural to wonder if immunohistochemical and anatomical methods disturb or damage the cells they are designed to examine. Tissue fixation is typically incorporated to guard against this damage and is therefore critically important to the quality and significance of the harvested data. Here, we describe mechanisms of fixation; advantages and disadvantages of using formaldehyde and glutaraldehyde as fixatives during immunohistochemistry; and modifications of widely used protocols that have recently been found to improve cell shape preservation and immunostaining patterns, especially in proximal retinal neurons. PMID:25892361

  13. The Role of Minimally Invasive Plate Osteosynthesis in Rib Fixation: A Review

    PubMed Central

    Bemelman, Michael; van Baal, Mark; Yuan, Jian Zhang; Leenen, Luke

    2016-01-01

    More than a century ago, the first scientific report was published about fracture fixation with plates. During the 1950’s, open reduction and plate fixation for fractures were standardized by the founders of Arbeitsgemeinschaft für osteosynthesefragen/Association for the Study of Internal Fixation. Since the introduction of plate fixation for fractures, several plates and screws have been developed, all with their own characteristics. To accomplice more fracture stability, it was thought the bigger the plate, the better. The counter side was a compromised blood supply of the bone, often resulting in bone necrosis and ultimately delayed or non-union. With the search and development of new materials and techniques for fracture fixation, less invasive procedures have become increasingly popular. This resulted in the minimally invasive plate osteosynthesis (MIPO) technique for fracture fixation. With the MIPO technique, procedures could be performed with smaller incisions and thus with less soft tissue damage and a better preserved blood supply. The last 5 years rib fixation has become increasingly popular, rising evidence has become available suggesting that surgical rib fixation improves outcome of patients with a flail chest or isolated rib fractures. Many surgical approaches for rib fixation have been described in the old literature, however, most of these techniques are obscure nowadays. Currently mostly large incisions with considerable surgical insult are used to stabilize rib fractures. We think that MIPO deserves a place in the surgical treatment of rib fractures. We present the aspects of diagnosis, preoperative planning and operative techniques in regard to MIPO rib fixation. PMID:26889439

  14. Tissue fixation and the effect of molecular fixatives on downstream staining procedures

    PubMed Central

    Howat, William J.; Wilson, Beverley A.

    2014-01-01

    It is impossible to underplay the importance of fixation in histopathology. Whether the scientist is interested in the extraction of information on lipids, proteins, RNA or DNA, fixation is critical to this extraction. This review aims to give a brief overview of the current “state of play” in fixation and focus on the effect fixation, and particularly the effect of the newer brand of “molecular fixatives” have on morphology, histochemistry, immunohistochemistry and RNA/DNA analysis. A methodology incorporating the creation of a fixation tissue microarray for the study of the effect of fixation on histochemistry is detailed. PMID:24561827

  15. An oculomotor continuum from exploration to fixation

    PubMed Central

    Otero-Millan, Jorge; Macknik, Stephen L.; Langston, Rachel E.; Martinez-Conde, Susana

    2013-01-01

    During visual exploration, saccadic eye movements scan the scene for objects of interest. During attempted fixation, the eyes are relatively still but often produce microsaccades. Saccadic rates during exploration are higher than those of microsaccades during fixation, reinforcing the classic view that exploration and fixation are two distinct oculomotor behaviors. An alternative model is that fixation and exploration are not dichotomous, but are instead two extremes of a functional continuum. Here, we measured the eye movements of human observers as they either fixed their gaze on a small spot or scanned natural scenes of varying sizes. As scene size diminished, so did saccade rates, until they were continuous with microsaccadic rates during fixation. Other saccadic properties varied as function of image size as well, forming a continuum with microsaccadic parameters during fixation. This saccadic continuum extended to nonrestrictive, ecological viewing conditions that allowed all types of saccades and fixation positions. Eye movement simulations moreover showed that a single model of oculomotor behavior can explain the saccadic continuum from exploration to fixation, for images of all sizes. These findings challenge the view that exploration and fixation are dichotomous, suggesting instead that visual fixation is functionally equivalent to visual exploration on a spatially focused scale. PMID:23533278

  16. INTRAOPERATIVE SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY IMAGING AFTER INTERNAL LIMITING MEMBRANE PEELING IN IDIOPATHIC EPIRETINAL MEMBRANE WITH CONNECTING STRANDS

    PubMed Central

    NAM, DONG HEUN; DESOUZA, PHILIP J.; HAHN, PAUL; TAI, VINCENT; SEVILLA, MONICA B.; TRAN-VIET, DU; CUNEFARE, DAVID; FARSIU, SINA; IZATT, JOSEPH A.; TOTH, CYNTHIA A.

    2015-01-01

    Purpose To report the intraoperative optical coherence tomography findings in idiopathic epiretinal membrane (ERM) with connecting strands and to describe the postoperative outcomes. Methods A retrospective, case series study within a prospective observational intraoperative optical coherence tomography imaging study was performed. Epiretinal membranes with connecting strands were characterized on preoperative spectral domain optical coherence tomography images and assessed against corresponding intraoperative (after internal limiting membrane [ILM] peeling) and postoperative spectral domain optical coherence tomography images. Results Eleven locations of the connecting strands in 7 eyes were studied. The connecting strands had visible connections from the inner retinal surface to the ERM in all locations, and the reflectivity was moderate in 8 locations and high in 3 locations. After ERM and ILM peeling, disconnected strands were identified in all of the intraoperative optical coherence tomography images. The reflectivity of the remaining intraoperative strands was higher than that of the preoperative lesions and appeared as “finger-like” and branching projections. The remaining disconnected lesions were contiguous with the inner retinal layers. Postoperatively, the intraoperative lesions disappeared completely in all locations, and recurrent formation of ERM was not identified in any eyes. Conclusion In ERM eyes with connecting strands, intraoperative spectral domain optical coherence tomography imaging showed moderately to highly reflective sub-ILM finger-like lesions that persist immediately after membrane and ILM peeling. Postoperatively, the hyperreflective lesions disappeared spontaneously without localized nerve fiber layer loss. The sub-ILM connecting strands may represent glial retinal attachments. PMID:25829349

  17. Analysis of operational, institutional and international limitations for alternative fuel vehicles and technologies: Means/methods for implementing changes

    NASA Astrophysics Data System (ADS)

    1992-07-01

    This project focused upon the development of an approach to assist public fleet managers in evaluating the characteristics and availability of alternative fuels (AF's) and alternative fuel vehicles (AFV's) that will serve as possible replacements for vehicles currently serving the needs of various public entities. Also of concern were the institutional/international limitations for alternative fuels and alternative fuel vehicles. The City of Detroit and other public agencies in the Detroit area were the particular focus for the activities. As the development and initial stages of use of alternative fuels and alternative fuel vehicles proceeds, there will be an increasing need to provide information and guidance to decision-makers regarding differences in requirements and features of these fuels and vehicles. There will be differences in requirements for servicing, managing, and regulating. There will also be misunderstanding and misperception. There have been volumes of data collected on AFV'S, and as technology is improved, new data is constantly added. There are not, however, condensed and effective sources of information for public vehicle fleet managers on vehicle and equipment sources, characteristics, performance, costs, and environmental benefits. While theoretical modeling of public fleet requirements has been done, there do not seem to be readily available 'practical'. There is a need to provide the best possible information and means to minimize the problems for introducing the effective use of alternative fuels and alternative fuel vehicles.

  18. Analysis of operational, institutional and international limitations for alternative fuel vehicles and technologies: Means/methods for implementing changes

    SciTech Connect

    Not Available

    1992-07-01

    This project focused upon the development of an approach to assist public fleet managers in evaluating the characteristics and availability of alternative fuels (AF`s) and alternative fuel vehicles (AFV`s) that will serve as possible replacements for vehicles currently serving the needs of various public entities. Also of concern were the institutional/international limitations for alternative fuels and alternative fuel vehicles. The City of Detroit and other public agencies in the Detroit area were the particular focus for the activities. As the development and initial stages of use of alternative fuels and alternative fuel vehicles proceeds, there will be an increasing need to provide information and guidance to decision-makers regarding differences in requirements and features of these fuels and vehicles. There wig be true differences in requirements for servicing, managing, and regulating. There will also be misunderstanding and misperception. There have been volumes of data collected on AFV`S, and as technology is improved, new data is constantly added. There are not, however, condensed and effective sources of information for public vehicle fleet managers on vehicle and equipment sources, characteristics, performance, costs, and environmental benefits. While theoretical modeling of public fleet requirements has been done, there do not seem to be readily available ``practical``. There is a need to provide the best possible information and means to minimize the problems for introducing the effective use of alternative fuels and alternative fuel vehicles.

  19. Relationship between Peeled Internal Limiting Membrane Area and Anatomic Outcomes following Macular Hole Surgery: A Quantitative Analysis.

    PubMed

    Goker, Yasin Sakir; Koc, Mustafa; Yuksel, Kemal; Yazici, Ahmet Taylan; Demir, Abdulvahit; Gunes, Hasan; Ozpinar, Yavuz

    2016-01-01

    Purpose. To quantitatively evaluate the effects of peeled internal limiting membrane (ILM) area and anatomic outcomes following macular hole surgery using spectral domain optical coherence tomography (SD-OCT). Methods. Forty-one eyes in 37 consecutive patients with idiopathic, Gass stage 3-4 macular hole (MH) were enrolled in this retrospective comparative study. All patients were divided into 2 groups according to anatomic success or failure. Basal MH diameter, peeled ILM area, and MH height were calculated using SD-OCT. Other prognostic parameters, including age, stage, preoperative BCVA, and symptom duration were also assessed. Results. Thirty-two cases were classified as anatomic success, and 9 cases were classified as anatomic failure. Peeled ILM area was significantly wider and MH basal diameter was significantly less in the anatomic success group (p = 0.024 and 0.032, resp.). Other parameters did not demonstrate statistical significance. Conclusion. The findings of the present study show that the peeled ILM area can affect the anatomic outcomes of MH surgery. PMID:27413544

  20. Relationship between Peeled Internal Limiting Membrane Area and Anatomic Outcomes following Macular Hole Surgery: A Quantitative Analysis

    PubMed Central

    Goker, Yasin Sakir; Koc, Mustafa; Yuksel, Kemal; Yazici, Ahmet Taylan; Gunes, Hasan; Ozpinar, Yavuz

    2016-01-01

    Purpose. To quantitatively evaluate the effects of peeled internal limiting membrane (ILM) area and anatomic outcomes following macular hole surgery using spectral domain optical coherence tomography (SD-OCT). Methods. Forty-one eyes in 37 consecutive patients with idiopathic, Gass stage 3-4 macular hole (MH) were enrolled in this retrospective comparative study. All patients were divided into 2 groups according to anatomic success or failure. Basal MH diameter, peeled ILM area, and MH height were calculated using SD-OCT. Other prognostic parameters, including age, stage, preoperative BCVA, and symptom duration were also assessed. Results. Thirty-two cases were classified as anatomic success, and 9 cases were classified as anatomic failure. Peeled ILM area was significantly wider and MH basal diameter was significantly less in the anatomic success group (p = 0.024 and 0.032, resp.). Other parameters did not demonstrate statistical significance. Conclusion. The findings of the present study show that the peeled ILM area can affect the anatomic outcomes of MH surgery. PMID:27413544

  1. A high-resolution study of surfactant partitioning and kinetic limitations for two-component internally mixed aerosols

    NASA Astrophysics Data System (ADS)

    Suda, S. R.; Petters, M. D.

    2013-12-01

    Atmospheric aerosols serve as cloud condensation nuclei (CCN), altering cloud properties and ultimately affecting climate through their effect on the radiative balance. Aerosol CCN activity depends in part on aerosol composition and surfactant compounds are of particular interest because surfactants are enriched at the water/air interface, resulting in a radial concentration gradient within the aqueous droplet. Accurate treatment of the surfactant concentration gradient complicates the otherwise straightforward predictions of CCN activity for aerosols of known composition. To accurately evaluate predictions made by theory, laboratory studies investigating the relationship between critical supersaturation and dry diameter of particles that include surfactants require significant reduction in measurement uncertainty for both water-uptake and CCN measurements. Furthermore, uncertainties remain regarding kinetic limitations to surfactant partitioning that could result in deviation from predictions based on equilibrium thermodynamics. This study attempts to address some of these issues through high-resolution analysis of CCN activity of two-component mixed surfactant/non-surfactant aerosols at different internal mixing ratios performed with and without a water-uptake time delay to ascertain whether or not the observed effects are kinetically limited. We present new data for the aerosols consisting of 1) the ionic surfactant sodium dodecyl sulfate (SDS) with ammonium sulfate, 2) SDS with sodium chloride and 3) the strong non-ionic fluorosurfactant Zonyl with an organic proxy glucose. As a point of reference we also evaluated the mixture of ammonium sulfate with glucose. Aerosol activation diameters were determined using CCN analysis in conjunction with scanning mobility size classification and high sheath-to-aerosol flow ratios. This resulted in CCN-derived kappa values that could be determined within +/-5% relative error. To test whether dynamic surfactant partitioning

  2. Overcoming fixation with repeated memory suppression.

    PubMed

    Angello, Genna; Storm, Benjamin C; Smith, Steven M

    2015-01-01

    Fixation (blocks to memories or ideas) can be alleviated not only by encouraging productive work towards a solution, but, as the present experiments show, by reducing counterproductive work. Two experiments examined relief from fixation in a word-fragment completion task. Blockers, orthographically similar negative primes (e.g., ANALOGY), blocked solutions to word fragments (e.g., A_L_ _GY) in both experiments. After priming, but before the fragment completion test, participants repeatedly suppressed half of the blockers using the Think/No-Think paradigm, which results in memory inhibition. Inhibiting blockers did not alleviate fixation in Experiment 1 when conscious recollection of negative primes was not encouraged on the fragment completion test. In Experiment 2, however, when participants were encouraged to remember negative primes at fragment completion, relief from fixation was observed. Repeated suppression may nullify fixation effects, and promote creative thinking, particularly when fixation is caused by conscious recollection of counterproductive information. PMID:24575886

  3. Distribution of nitrogen fixation and nitrogenase-like sequences amongst microbial genomes

    PubMed Central

    2012-01-01

    Background The metabolic capacity for nitrogen fixation is known to be present in several prokaryotic species scattered across taxonomic groups. Experimental detection of nitrogen fixation in microbes requires species-specific conditions, making it difficult to obtain a comprehensive census of this trait. The recent and rapid increase in the availability of microbial genome sequences affords novel opportunities to re-examine the occurrence and distribution of nitrogen fixation genes. The current practice for computational prediction of nitrogen fixation is to use the presence of the nifH and/or nifD genes. Results Based on a careful comparison of the repertoire of nitrogen fixation genes in known diazotroph species we propose a new criterion for computational prediction of nitrogen fixation: the presence of a minimum set of six genes coding for structural and biosynthetic components, namely NifHDK and NifENB. Using this criterion, we conducted a comprehensive search in fully sequenced genomes and identified 149 diazotrophic species, including 82 known diazotrophs and 67 species not known to fix nitrogen. The taxonomic distribution of nitrogen fixation in Archaea was limited to the Euryarchaeota phylum; within the Bacteria domain we predict that nitrogen fixation occurs in 13 different phyla. Of these, seven phyla had not hitherto been known to contain species capable of nitrogen fixation. Our analyses also identified protein sequences that are similar to nitrogenase in organisms that do not meet the minimum-gene-set criteria. The existence of nitrogenase-like proteins lacking conserved co-factor ligands in both diazotrophs and non-diazotrophs suggests their potential for performing other, as yet unidentified, metabolic functions. Conclusions Our predictions expand the known phylogenetic diversity of nitrogen fixation, and suggest that this trait may be much more common in nature than it is currently thought. The diverse phylogenetic distribution of nitrogenase

  4. Molecular fixative enables expression microarray analysis of microdissected clinical cervical specimens.

    PubMed

    Li, Gerald; van Niekerk, Dirk; Miller, Dianne; Ehlen, Thomas; Garnis, Cathie; Follen, Michele; Guillaud, Martial; Macaulay, Calum

    2014-04-01

    Formalin-fixed tissue has been a mainstay of clinical pathology laboratories, but formalin alters many biomolecules, including nucleic acids and proteins. Meanwhile, frozen tissues contain better-preserved biomolecules, but tissue morphology is affected, limiting their diagnostic utility. Molecular fixatives promise to bridge this gap by simultaneously preserving morphology and biomolecules, enabling clinical diagnosis and molecular analyses on the same specimen. While previous reports have broadly evaluated the use of molecular fixative in various human tissues, we present here the first detailed assessment of the applicability of molecular fixative to both routine histopathological diagnosis and molecular analysis of cervical tissues. Ten specimens excised via the loop electrosurgical excision procedure, which removes conical tissue samples from the cervix, were cut into alternating pieces preserved in either formalin or molecular fixative. Cervical specimens preserved in molecular fixative were easily interpretable, despite featuring more eosinophilic cytoplasm and more recognizable chromatin texture than formalin-fixed specimens. Immunohistochemical staining patterns of p16 and Ki-67 were similar between fixatives, although Ki-67 staining was stronger in the molecular fixative specimens. The RNA of molecular fixative specimens from seven cases representing various dysplasia grades was assessed for utility in expression microarray analysis. Cluster analysis and scatter plots of duplicate samples suggest that data of sufficient quality can be obtained from as little as 50ng of RNA from molecular fixative samples. Taken together, our results show that molecular fixative may be a more versatile substitute for formalin, simultaneously preserving tissue morphology for clinical diagnosis and biomolecules for immunohistochemistry and gene expression analysis. PMID:24412268

  5. Two-Pin Fixation of Proximal Interphalangeal Joint Fusion for Hammertoe Correction.

    PubMed

    Boffeli, Troy J; Thompson, Jonathan C; Tabatt, Jessica A

    2016-01-01

    Single-pin external Kirschner wire (K-wire) fixation has traditionally been a mainstay in proximal interphalangeal joint fusion for central hammertoe repair. Concerns over cosmesis, inconvenience, pin tract infection, hardware failure, nonunion, and early hardware removal have led to the development of implantable internal fixation devices. Although numerous implantable devices are now available and represent viable options for hammertoe repair, they are costly and often pose a challenge in the event removal becomes necessary. An alternative fixation option not typically used is a 2-pin K-wire fixation technique. The perceived advantage of obtaining 2 points of fixation compared with 1 across the fusion site is improved stability against the rotational and bending forces, thus decreasing the potential for pin-related complications. A retrospective assessment of 91 consecutive hammertoe repairs consisting of proximal interphalangeal joint fusion with 2-pin fixation in 60 patients was performed. The K-wires were removed at 6 weeks postoperatively, and the overall postoperative follow-up duration was 28.56 (range 1.40 to 86.83) months. Of the 91 digits, 89 (98%) did not encounter a complication postoperatively and 2 (2.20%) had sustained loosened or broken hardware. No postoperative infection was encountered. The low incidence of complications observed supports the 2-pin K-wire fixation technique as a low-cost and viable construct for proximal interphalangeal joint fusion hammertoe repair. PMID:26878808

  6. Nitrogen fixation method and apparatus

    DOEpatents

    Chen, H.L.

    1983-08-16

    A method and apparatus for achieving nitrogen fixation includes a volumetric electric discharge chamber. The volumetric discharge chamber provides an even distribution of an electron beam, and enables the chamber to be maintained at a controlled energy to pressure (E/p) ratio. An E/p ratio of from 5 to 15 kV/atm of O[sub 2]/cm promotes the formation of vibrationally excited N[sub 2]. Atomic oxygen interacts with vibrationally excited N[sub 2] at a much quicker rate than unexcited N[sub 2], greatly improving the rate at which NO is formed. 1 fig.

  7. Image recorder with microwave fixation

    SciTech Connect

    Hosono, N.; Isaka, K.

    1984-11-13

    The present invention is directed to improvement in an image recorder for recording developed images or toner images by microwave fixation. According to the invention there is used a novel thermoplastic developer comprising of two components. The first component contains a dielectric material which is able to absorb microwave and generate heat by dielectric loss. The second component contains magnetic loss exothermic material. The microwave absorbing power of the first component is improved by heating the first component with heat generated from the second component.

  8. Nitrogen fixation method and apparatus

    DOEpatents

    Chen, Hao-Lin

    1983-01-01

    A method and apparatus for achieving nitrogen fixation includes a volumetric electric discharge chamber. The volumetric discharge chamber provides an even distribution of an electron beam, and enables the chamber to be maintained at a controlled energy to pressure (E/p) ratio. An E/p ratio of from 5 to 15 kV/atm of O.sub.2 /cm promotes the formation of vibrationally excited N.sub.2. Atomic oxygen interacts with vibrationally excited N.sub.2 at a much quicker rate than unexcited N.sub.2, greatly improving the rate at which NO is formed.

  9. Proposed Use of the Computer as a Tool to Aid Analysis of Properties of Materials in Fixators of Spine

    PubMed Central

    Santos, Antonio; Moreira, Fernando

    2014-01-01

    With objective of analyzing the mechanical behavior of the internal fixators of spine and of the bony structure, the pieces and the group were made (it structures bony x internal fixator) with the aid a software of solid modeling. The materials used in the rehearsals had been the titanium, now in the market and a castor oil polyurethane destined to the development of you implant bony. PMID:24825938

  10. Do Fixation Cues Ensure Fixation Accuracy in Split-Fovea Studies of Word Recognition?

    ERIC Educational Resources Information Center

    Jordan, Timothy R.; Paterson, Kevin B.; Kurtev, Stoyan; Xu, Mengyun

    2009-01-01

    Many studies have claimed that hemispheric processing is split precisely at the foveal midline and so place great emphasis on the precise location at which words are fixated. These claims are based on experiments in which a variety of fixation procedures were used to ensure fixation accuracy but the effectiveness of these procedures is unclear. We…

  11. The sustentaculum tali screw fixation for the treatment of Sanders type II calcaneal fracture: A finite element analysis

    PubMed Central

    Pang, Qing-Jiang; Yu, Xiao; Guo, Zong-Hui

    2014-01-01

    Objective: In the surgery of calcaneal fracture, whether the sustentaculum tali screw should always be placed is widely controversial. The aim of this study was to explore the necessity and function of the sustentaculum tali screw placement for the treatment of Sanders type II calcaneal fracture. Methods: The finite element analysis was used in this study. After the establishment of the finite element model of Sanders type II calcaneal fracture, the two internal fixation simulations were designed. In one model, the AO calcaneal plate was simulated on the lateral side of the calcanues with 7 screws being fixated at different position of the plate. In the other model, the calcaneus was fixated with the same AO calcaneal plate together with an additional screw being infiltrated into the sustentaculum tali. The two models were simulated under the same loading and the displacement of the fracture line and the stress distribution in the two models were calculated respectively. Results: The maximum principal stress focused on the cortical bone of sustentaculum tali in both the models under the same loading. The displacement of the fracture line, the maximum principal stress of calcaneus and internal fixation system in the model with sustentaculum screw fixation were smaller than that in the model without sustentaculum screw fixation. The stress in the model with sustentaculum screw fixation was more dispersed. Conclusions: The placement of sustentaculum tali screw is essential for fixation of type II calcaneal fracture to achieve the biomechanical stability. PMID:25225534

  12. Carbon fixation by basalt-hosted microbial communities

    PubMed Central

    Orcutt, Beth N.; Sylvan, Jason B.; Rogers, Daniel R.; Delaney, Jennifer; Lee, Raymond W.; Girguis, Peter R.

    2015-01-01

    Oceanic crust is a massive potential habitat for microbial life on Earth, yet our understanding of this ecosystem is limited due to difficulty in access. In particular, measurements of rates of microbial activity are sparse. We used stable carbon isotope incubations of crustal samples, coupled with functional gene analyses, to examine the potential for carbon fixation on oceanic crust. Both seafloor-exposed and subseafloor basalts were recovered from different mid-ocean ridge and hot spot environments (i.e., the Juan de Fuca Ridge, the Mid-Atlantic Ridge, and the Loihi Seamount) and incubated with 13C-labeled bicarbonate. Seafloor-exposed basalts revealed incorporation of 13C-label into organic matter over time, though the degree of incorporation was heterogeneous. The incorporation of 13C into biomass was inconclusive in subseafloor basalts. Translating these measurements into potential rates of carbon fixation indicated that 0.1–10 nmol C g-1rock d-1 could be fixed by seafloor-exposed rocks. When scaled to the global production of oceanic crust, this suggests carbon fixation rates of 109–1012 g C year-1, which matches earlier predictions based on thermodynamic calculations. Functional gene analyses indicate that the Calvin cycle is likely the dominant biochemical mechanism for carbon fixation in basalt-hosted biofilms, although the reductive acetyl-CoA pathway and reverse TCA cycle likely play some role in net carbon fixation. These results provide empirical evidence for autotrophy in oceanic crust, suggesting that basalt-hosted autotrophy could be a significant contributor of organic matter in this remote and vast environment. PMID:26441854

  13. Carbon fixation by basalt-hosted microbial communities.

    PubMed

    Orcutt, Beth N; Sylvan, Jason B; Rogers, Daniel R; Delaney, Jennifer; Lee, Raymond W; Girguis, Peter R

    2015-01-01

    Oceanic crust is a massive potential habitat for microbial life on Earth, yet our understanding of this ecosystem is limited due to difficulty in access. In particular, measurements of rates of microbial activity are sparse. We used stable carbon isotope incubations of crustal samples, coupled with functional gene analyses, to examine the potential for carbon fixation on oceanic crust. Both seafloor-exposed and subseafloor basalts were recovered from different mid-ocean ridge and hot spot environments (i.e., the Juan de Fuca Ridge, the Mid-Atlantic Ridge, and the Loihi Seamount) and incubated with (13)C-labeled bicarbonate. Seafloor-exposed basalts revealed incorporation of (13)C-label into organic matter over time, though the degree of incorporation was heterogeneous. The incorporation of (13)C into biomass was inconclusive in subseafloor basalts. Translating these measurements into potential rates of carbon fixation indicated that 0.1-10 nmol C g(-1) rock d(-1) could be fixed by seafloor-exposed rocks. When scaled to the global production of oceanic crust, this suggests carbon fixation rates of 10(9)-10(12) g C year(-1), which matches earlier predictions based on thermodynamic calculations. Functional gene analyses indicate that the Calvin cycle is likely the dominant biochemical mechanism for carbon fixation in basalt-hosted biofilms, although the reductive acetyl-CoA pathway and reverse TCA cycle likely play some role in net carbon fixation. These results provide empirical evidence for autotrophy in oceanic crust, suggesting that basalt-hosted autotrophy could be a significant contributor of organic matter in this remote and vast environment. PMID:26441854

  14. Heterotrophic organisms dominate nitrogen fixation in the South Pacific Gyre

    PubMed Central

    Halm, Hannah; Lam, Phyllis; Ferdelman, Timothy G; Lavik, Gaute; Dittmar, Thorsten; LaRoche, Julie; D'Hondt, Steven; Kuypers, Marcel MM

    2012-01-01

    Oceanic subtropical gyres are considered biological deserts because of the extremely low availability of nutrients and thus minimum productivities. The major source of nutrient nitrogen in these ecosystems is N2-fixation. The South Pacific Gyre (SPG) is the largest ocean gyre in the world, but measurements of N2-fixation therein, or identification of microorganisms involved, are scarce. In the 2006/2007 austral summer, we investigated nitrogen and carbon assimilation at 11 stations throughout the SPG. In the ultra-oligotrophic waters of the SPG, the chlorophyll maxima reached as deep as 200 m. Surface primary production seemed limited by nitrogen, as dissolved inorganic carbon uptake was stimulated upon additions of 15N-labeled ammonium and leucine in our incubation experiments. N2-fixation was detectable throughout the upper 200 m at most stations, with rates ranging from 0.001 to 0.19 nM N h−1. N2-fixation in the SPG may account for the production of 8–20% of global oceanic new nitrogen. Interestingly, comparable 15N2-fixation rates were measured under light and dark conditions. Meanwhile, phylogenetic analyses for the functional gene biomarker nifH and its transcripts could not detect any common photoautotrophic diazotrophs, such as, Trichodesmium, but a prevalence of γ-proteobacteria and the unicellular photoheterotrophic Group A cyanobacteria. The dominance of these likely heterotrophic diazotrophs was further verified by quantitative PCR. Hence, our combined results show that the ultra-oligotrophic SPG harbors a hitherto unknown heterotrophic diazotrophic community, clearly distinct from other oceanic gyres previously visited. PMID:22170429

  15. Experimental study in order to assess the effects of limited periosteum stripping on the fracture healing and to compare osteosynthesis using plates and screws with intramedullary Kirschner wire fixation.

    PubMed

    Neagu, Tiberiu Paul; Enache, Valentin; Cocoloş, Ion; Ţigliş, Mirela; Cobilinschi, Cristian; Ţincu, Radu

    2016-01-01

    There are many studies that investigate indirect and direct fracture healing but few mention the effect of periosteum stripping on consolidation of fractures. Most of these studies use only one method of osteosynthesis for each group. Therefore, we reported a new developed murine model in order to assess if limited periosteum stripping influence significantly the quality of the fracture healing process by comparing two different osteosynthesis methods to reduce simultaneously bilateral femur fractures. We applied the experimental protocol for a number of 12 rats. We used plates and screws to reduce femoral osteotomy for the right hind limb and intramedullary Kirschner wire for the left hind limb. Clinical, radiological and histological assessments were made for a period of eight weeks. The absence of a healthy hind limb led to a slower healing process based on the histological findings and to implant failure based on radiological findings. In summary, complete fracture healing was not achieved during this experimental study. Therefore, we consider that future studies are needed for a better understanding of the effects of periosteum removal on the fracture healing process. PMID:27516016

  16. Occipital condyle to cervical spine fixation in the pediatric population.

    PubMed

    Kosnik-Infinger, Libby; Glazier, Steven S; Frankel, Bruce M

    2014-01-01

    Fixation at the craniovertebral junction (CVJ) is necessary in a variety of pediatric clinical scenarios. Traditionally an occipital bone to cervical fusion is preformed, which requires a large amount of hardware to be placed on the occiput of a child. If a patient has previously undergone a posterior fossa decompression or requires a decompression at the time of the fusion procedure, it can be difficult to anchor a plate to the occipital bone. The authors propose a technique that can be used when faced with this difficult challenge by using the occipital condyle as a point of fixation for the construct. Adult cadaveric and a limited number of case studies have been published using occipital condyle (C-0) fixation. This work was adapted for the pediatric population. Between 2009 and 2012, 4 children underwent occipital condyle to axial or subaxial spine fixation. One patient had previously undergone posterior fossa surgery for tumor resection, and 1 required decompression at the time of operation. Two patients underwent preoperative deformity reduction using traction. One child had a Chiari malformation Type I. Each procedure was performed using polyaxial screw-rod constructs with intraoperative neuronavigation supplemented by a custom navigational drill guide. Smooth-shanked 3.5-mm polyaxial screws, ranging in length from 26 to 32 mm, were placed into the occipital condyles. All patients successfully underwent occipital condyle to cervical spine fixation. In 3 patients the construct extended from C-0 to C-2, and in 1 from C-0 to T-2. Patients with preoperative halo stabilization were placed in a cervical collar postoperatively. There were no new postoperative neurological deficits or vascular injuries. Each patient underwent postoperative CT, demonstrating excellent screw placement and evidence of solid fusion. Occipital condyle fixation is an effective option in pediatric patients requiring occipitocervical fusion for treatment of deformity and/or instability at

  17. Molecular evidence for sediment nitrogen fixation in a temperate New England estuary

    PubMed Central

    Newell, Silvia E.; Pritchard, Kaitlyn R.; Foster, Sarah Q.

    2016-01-01

    Primary production in coastal waters is generally nitrogen (N) limited with denitrification outpacing nitrogen fixation (N2-fixation). However, recent work suggests that we have potentially underestimated the importance of heterotrophic sediment N2-fixation in marine ecosystems. We used clone libraries to examine transcript diversity of nifH (a gene associated with N2-fixation) in sediments at three sites in a temperate New England estuary (Waquoit Bay, Massachusetts, USA) and compared our results to net sediment N2 fluxes previously measured at these sites. We observed nifH expression at all sites, including a site heavily impacted by anthropogenic N. At this N impacted site, we also observed mean net sediment N2-fixation, linking the geochemical rate measurement with nifH expression. This same site also had the lowest diversity (non-parametric Shannon = 2.75). At the two other sites, we also detected nifH transcripts, however, the mean N2 flux indicated net denitrification. These results suggest that N2-fixation and denitrification co-occur in these sediments. Of the unique sequences in this study, 67% were most closely related to uncultured bacteria from various marine environments, 17% to Cluster III, 15% to Cluster I, and only 1% to Cluster II. These data add to the growing body of literature that sediment heterotrophic N2-fixation, even under high inorganic nitrogen concentrations, may be an important yet overlooked source of N in coastal systems. PMID:26977375

  18. Nitrogen Inputs via Nitrogen Fixation in Northern Plants and Soils

    NASA Astrophysics Data System (ADS)

    Thorp, N. R.; Wieder, R. K.; Vile, M. A.

    2015-12-01

    Dominated by cold and often acidic water logged environments, mineralization of organic matter is slow in the majority of northern ecosystems. Measures of extractable ammonium and nitrate are generally low and can be undetectable in peat pore waters. Despite this apparent nitrogen limitation, many of these environments produce deep deposits of soil organic matter. Biological nitrogen fixation carried out by autotrophic and heterotrophic diazotrophs associated with cryptograms provides the majority of known nitrogen inputs in these northern ecosystems. Nitrogen fixation was assessed in a variety of northern soils within rhizospheres of dominant plant communities. We investigated the availability of this newly fixed nitrogen to the vascular plant community in nitrogen limited northern plant communities. We tracked nitrogen flow from 15N2 gas fixed in Sphagnum mosses into tissues of two native vascular plant species, boreal cranberry (Vaccinium oxycoccus) and black spruce (Picea mariana). 15N-labeled Sphagnum microcosms were grown within variable mesh size exclusion/inclusion fabrics in a nitrogen addition experiment in situ in order to investigate the role of mycorrhizal fungi in the uptake of newly fixed nitrogen. Up to 24% of daily fixed 15N label was transferred to vascular plant tissues during 2 months. Nitrogen addition resulted in decreased N2 fixation rates; however, with higher nitrogen availability there was a higher rate of 15N label uptake into the vascular plants, likely the result of increased production of dissolved organic nitrogen. Reliance on mycorrhizal networks for nitrogen acquisition was indicated by nitrogen isotope fractionation patterns. Moreover, N2 fixation activities in mosses were stimulated when vascular plants were grown in moss microcosms versus "moss only" treatments. Results indicate that bog vascular plants may derive considerable nitrogen from atmospheric N2 biologically fixed within Sphagnum mosses. This work demonstrates that

  19. Biochemical Approaches to Improved Nitrogen Fixation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improving symbiotic nitrogen fixation by legumes has emerged again as an important topic on the world scene due to the energy crisis and lack of access to nitrogen fertilizer in developing countries. We have taken a biochemical genomics approach to improving symbiotic nitrogen fixation in legumes. L...

  20. 21 CFR 886.1290 - Fixation device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Fixation device. 886.1290 Section 886.1290 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1290 Fixation device. (a) Identification. A...

  1. 21 CFR 886.1290 - Fixation device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Fixation device. 886.1290 Section 886.1290 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1290 Fixation device. (a) Identification. A...

  2. 21 CFR 886.1290 - Fixation device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Fixation device. 886.1290 Section 886.1290 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1290 Fixation device. (a) Identification. A...

  3. Whole Animal Perfusion Fixation for Rodents

    PubMed Central

    Gage, Gregory J.; Kipke, Daryl R.; Shain, William

    2012-01-01

    The goal of fixation is to rapidly and uniformly preserve tissue in a life-like state. While placing tissue directly in fixative works well for small pieces of tissue, larger specimens like the intact brain pose a problem for immersion fixation because the fixative does not reach all regions of the tissue at the same rate 5,7. Often, changes in response to hypoxia begin before the tissue can be preserved 12. The advantage of directly perfusing fixative through the circulatory system is that the chemical can quickly reach every corner of the organism using the natural vascular network. In order to utilize the circulatory system most effectively, care must be taken to match physiological pressures 3. It is important to note that physiological pressures are dependent on the species used. Techniques for perfusion fixation vary depending on the tissue to be fixed and how the tissue will be processed following fixation. In this video, we describe a low-cost, rapid, controlled and uniform fixation procedure using 4% paraformaldehyde perfused via the vascular system: through the heart of the rat to obtain the best possible preservation of the brain for immunohistochemistry. The main advantage of this technique (vs. gravity-fed systems) is that the circulatory system is utilized most effectively. PMID:22871843

  4. Combined use of Ilizarov external fixation and Papineau technique for septic pseudoarthrosis of the distal tibia in a patient with diabetes mellitus

    PubMed Central

    Koutsostathis, Stefanos D.; Lepetsos, Panagiotis; Polyzois, Vasilios D.; Pneumaticos, Spyros G.; Macheras, George A.

    2014-01-01

    The surgical treatment of open pilon fractures has a high complication rate especially in diabetic patients. In this article, we present a case of an infected tibial non-union after an open reduction and internal fixation in a diabetic patient, treated with Ilizarov external fixation combined with Papineau technique. Combined use of external fixation and Papineau technique can provide an alternative option for the treatment of septic pseudoarthrosis of the distal tibia. PMID:24563728

  5. Combined use of Ilizarov external fixation and Papineau technique for septic pseudoarthrosis of the distal tibia in a patient with diabetes mellitus.

    PubMed

    Koutsostathis, Stefanos D; Lepetsos, Panagiotis; Polyzois, Vasilios D; Pneumaticos, Spyros G; Macheras, George A

    2014-01-01

    The surgical treatment of open pilon fractures has a high complication rate especially in diabetic patients. In this article, we present a case of an infected tibial non-union after an open reduction and internal fixation in a diabetic patient, treated with Ilizarov external fixation combined with Papineau technique. Combined use of external fixation and Papineau technique can provide an alternative option for the treatment of septic pseudoarthrosis of the distal tibia. PMID:24563728

  6. Outcome comparison of Lisfranc injuries treated through dorsal plate fixation versus screw fixation

    PubMed Central

    Hu, Sun-jun; Chang, Shi-min; Li, Xiao-hua; Yu, Guang-rong

    2014-01-01

    OBJECTIVE: The objective of this prospective study was to test whether the treatment of Lisfranc injuries with open reduction and dorsal plate fixation would have the same or better functional outcomes as treatment with standard trans-articular screw fixation. METHODS: Sixty patients with primarily isolated Lisfranc joint injury were treated by open reduction and dorsal plate fixation or standard screw fixation. The patients were followed on average for 31 months. Evaluation was performed with patients' chief complaint, clinical examination, radiography, and AOFAS Midfoot Scale. RESULTS: Thirty two patients were treated with open reduction and dorsal plate fixation, and twenty eight patients were treated with open reduction and screw fixation. After two years follow-up, the mean AOFAS Midfoot score was 83.1 points in the dorsal plate fixation group and 78.5 points in the screw fixation group (p<0.01). Of the dorsal plate fixation group, radiographic analysis revealed anatomic reduction in twenty-nine patients (90.6%, 29/32) and nonanatomic reduction in three patients. Of the screw fixation group, radiographic analysis revealed anatomic reduction in twenty-three patients and nonanatomic reduction in five patients (82.1%, 23/28). CONCLUSIONS: Open reduction and dorsal plate fixation for a dislocated Lisfranc injury do have better short and median term outcome and a lower reoperation rate than standard screw ORIF. In our experience, we recommend using dorsal plate in ORIF on dislocated Lisfranc injuries. Level of Evidence II, Prospective Comparative Study. PMID:25538478

  7. Soil nutrients, land use history and species composition interact to influence tropical N2 fixation

    NASA Astrophysics Data System (ADS)

    Batterman, S. A.; Hall, J.; Van Breugel, M.; Hedin, L. O.

    2011-12-01

    Symbiotic di-nitrogen fixation plays an important role in terrestrial biogeochemical cycles as it can bring in large quantities of nitrogen into ecosystems and provide the nitrogen required for individual plant growth in nitrogen limited environments. Of particular interest is how fixation interacts with nitrogen and phosphorus cycles in heterogeneous tropical forests. Recent advances on this topic using plants grown in a shadehouse show that the interaction of nitrogen and phosphorus control fixation at the level of individual plants and that plants adjust nutrient acquisition strategies with some successes at overcoming nutrient limitation on biomass growth depending on nutrient availability and the strategy employed (Batterman et al. unpublished). Exactly how these results translate to biodiverse tropical forests with heterogeneous resource availabilities and a history of land use disturbances, however, remains largely unresolved. We surveyed fixation across a chronosequence of forest stands in Panama that were at various stages of recovery from the abandonment of cattle pasture. Stands ranged in age from new secondary regrowth to mature forest. We examined nine common species of putative N2 fixing trees and lianas for nodulation, tree size, and abundance for four stands each of four forest ages to determine if species differ in strategies and function. In addition, we measured light availability to each tree and total and bioavailable phosphorus and nitrogen for each stand to examine the interactions of fixation with these biogeochemical cycles. Results were scaled to estimate stand level fixation. We found unique patterns in fixation that contrasted with predictions based on evidence of how fixation interacts with land use and biogeochemical cycles in extra-tropical forests. Soil nutrients showed unexpected patterns in availability across the chronosequence and interacted with fixation. Finally, species displayed distinct differences in temporal patterns in

  8. Optimizing Stability in Femoral Neck Fracture Fixation.

    PubMed

    Ye, Ye; Hao, Jiandong; Mauffrey, Cyril; Hammerberg, E Mark; Stahel, Philip F; Hak, David J

    2015-10-01

    Optimizing stability of femoral neck fracture fixation is important in obtaining a successful outcome. The mechanical problems and strategies for achieving optimal stability differ depending on patients' age and degree of osteoporosis. Femoral neck fractures in younger adults usually result from high-energy trauma and have a vertical fracture pattern. Strategies for optimizing fixation stability in this group include placing additional screws at right angles to the fracture plane and medial buttress plate augmentation. In elderly patients, screw position relative to the intact cortical femoral neck bone is of critical importance. Additional strategies for optimizing fixation stability in this group include the concept of length stable fixation, use of adjunctive calcium phosphate cement, and use of novel fixed angle fixation implants. PMID:26488776

  9. Visual Fixation in Chiari Type II Malformation

    PubMed Central

    Salman, Michael S.; Sharpe, James A.; Lillakas, Linda; Dennis, Maureen; Steinbach, Martin J.

    2011-01-01

    Chiari type II malformation is a congenital deformity of the hindbrain. Square wave jerks are horizontal involuntary saccades that interrupt fixation. Cerebellar disorders may be associated with frequent square wave jerks or saccadic oscillations such as ocular flutter. The effects of Chiari type II malformation on visual fixation are unknown. We recorded eye movements using an eye tracker in 21 participants with Chiari type II malformation, aged 8 to 19 years while they fixated a target for 1 minute. Thirty-eight age-matched healthy participants served as controls. Square wave jerks’ parameters were similar in the 2 groups. Saccadic oscillations were not seen. Chiari type II malformation is not associated with pathological square wave jerks or abnormal saccadic oscillations. The congenital nature of this deformity may permit compensation that preserves stable visual fixation. Alternatively, the deformity of Chiari type II malformation may spare parts of the cerebellum that usually cause fixation instability when damaged. PMID:19182152

  10. Subperiosteal brow lifts without fixation.

    PubMed

    Troilius, Carl

    2004-11-01

    Most surgeons today advocate an endoscopic subperiosteal brow lift for surgical correction of the upper third of the face. At the author's clinic, this operation has been performed since 1994 and the subgaleal bicoronal brow lift is no longer used. In earlier investigations, the author showed that the subperiosteal approach (n = 60) gives a better result than the subgaleal method (n = 60) when compared 1 year after surgery. In the literature, however, there are no published data regarding the long-term results of subperiosteal brow lifts. The author took material from his earlier investigations and looked at the same patients 5 years postoperatively. He compared the subperiosteal approach (n = 30) with the subgaleal brow lift (n = 15) and found that after 5 years the brows of the subgaleal patients were on the same level as they were before surgery, but in the group of subperiosteal brow lifts, almost all of the brows were higher 5 years after surgery than they were 1 year after surgery, with a mean increase in height of 2.5 mm. These findings led the author to the question whether scalp fixation was necessary at all when performing a subperiosteal brow lift. He performed 20 subperiosteal endoscopic brow lifts where scalp fixation was not used at all, relying only on changing the balance of muscle vectors around the eyebrows. Using a computerized instrument, measurements were made of the distance between the medial canthus and the top of the eyebrow, the midpupil and the top of the eyebrow, and the lateral canthus and the top of the eyebrow. All patients were measured before and 1 year after surgery. The author found an increase of the vertical height from the midpupil to the top of the brow, with an average increase of 3.9 mm. There were no differences between patients who had only a brow lift and those who had a brow lift and an upper blepharoplasty at the same time. The author concludes that for most cases where an increased vertical height of the brows of more

  11. Abnormal Fixational Eye Movements in Amblyopia

    PubMed Central

    Shaikh, Aasef G.; Otero-Millan, Jorge; Kumar, Priyanka; Ghasia, Fatema F.

    2016-01-01

    Purpose Fixational saccades shift the foveal image to counteract visual fading related to neural adaptation. Drifts are slow eye movements between two adjacent fixational saccades. We quantified fixational saccades and asked whether their changes could be attributed to pathologic drifts seen in amblyopia, one of the most common causes of blindness in childhood. Methods Thirty-six pediatric subjects with varying severity of amblyopia and eleven healthy age-matched controls held their gaze on a visual target. Eye movements were measured with high-resolution video-oculography during fellow eye-viewing and amblyopic eye-viewing conditions. Fixational saccades and drifts were analyzed in the amblyopic and fellow eye and compared with controls. Results We found an increase in the amplitude with decreased frequency of fixational saccades in children with amblyopia. These alterations in fixational eye movements correlated with the severity of their amblyopia. There was also an increase in eye position variance during drifts in amblyopes. There was no correlation between the eye position variance or the eye velocity during ocular drifts and the amplitude of subsequent fixational saccade. Our findings suggest that abnormalities in fixational saccades in amblyopia are independent of the ocular drift. Discussion This investigation of amblyopia in pediatric age group quantitatively characterizes the fixation instability. Impaired properties of fixational saccades could be the consequence of abnormal processing and reorganization of the visual system in amblyopia. Paucity in the visual feedback during amblyopic eye-viewing condition can attribute to the increased eye position variance and drift velocity. PMID:26930079

  12. Phytoplankton carbon fixation, chlorophyll-biomass and diagnostic pigments in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Poulton, Alex J.; Holligan, Patrick M.; Hickman, Anna; Kim, Young-Nam; Adey, Tim R.; Stinchcombe, Mark C.; Holeton, Claire; Root, Sarah; Woodward, E. Malcolm S.

    2006-07-01

    We have made daily measurements of phytoplankton pigments, size-fractionated (<2 and >2-μm) carbon fixation and chlorophyll- a concentration during four Atlantic Meridional Transect (AMT) cruises in 2003-04. Surface rates of carbon fixation ranged from <0.2-mmol C m -3 d -1 in the subtropical gyres to 0.2-0.5-mmol C m -3 d -1 in the tropical equatorial Atlantic. Significant intercruise variability was restricted to the subtropical gyres, with higher chlorophyll- a concentrations and carbon fixation in the subsurface chlorophyll maximum during spring in either hemisphere. In surface waters, although picoplankton (<2-μm) represented the dominant fraction in terms of both carbon fixation (50-70%) and chlorophyll- a (80-90%), nanoplankton (>2-μm) contributions to total carbon fixation (30-50%) were higher than to total chlorophyll- a (10-20%). However, in the subsurface chlorophyll maximum picoplankton dominated both carbon fixation (70-90%) and chlorophyll- a (70-90%). Thus, in surface waters chlorophyll-normalised carbon fixation was 2-3 times higher for nanoplankton and differences in picoplankton and nanoplankton carbon to chlorophyll- a ratios may lead to either higher or similar growth rates. These low chlorophyll-normalised carbon fixation rates for picoplankton may also reflect losses of fixed carbon (cell leakage or respiration), decreases in photosynthetic efficiency, grazing losses during the incubations, or some combination of all these. Comparison of nitrate concentrations in the subsurface chlorophyll maximum with estimates of those required to support the observed rates of carbon fixation (assuming Redfield stoichiometry) indicate that primary production in the chlorophyll maximum may be light rather than nutrient limited.

  13. Biomechanical failure of metacarpal fracture resorbable plate fixation.

    PubMed

    Lionelli, Gerald T; Korentager, Richard A

    2002-08-01

    Metacarpal fractures are a relatively common hand injury that may require operative intervention to ensure adequate reduction and stabilization. The use of permanent hardware, although acceptable, may lead to complications and an increased number of surgical procedures. The use of resorbable hardware such as poly-L-lactic acid and polyglycolic acid copolymer plates and screws may circumvent some of these complications. In vitro studies have demonstrated that the biomechanical characteristics of these resorbable plates may provide the rigid fixation necessary to allow for union of metacarpal fractures in vivo. However, limited clinical data are available regarding the success of their use in this application. The authors present what they believe is the first reported case of the failure of a poly-L-lactic acid and polyglycolic acid copolymer miniplate after use in the fixation of a metacarpal shaft fracture. PMID:12187350

  14. Complement fixation by rheumatoid factor.

    PubMed Central

    Tanimoto, K; Cooper, N R; Johnson, J S; Vaughan, J H

    1975-01-01

    The capacity for fixation and activation of hemolytic complement by polyclonal IgM rheumatoid factors (RF) isolated from sera of patients with rheumatoid arthritis and monoclonal IgM-RF isolated from the cryoprecipitates of patients with IgM-IgG mixed cryoglobulinemia was examined. RF mixed with aggregated, reduced, and alkylated human IgG (Agg-R/A-IgG) in the fluid phase failed to significantly reduce the level of total hemolytic complement, CH50, or of individual complement components, C1, C2, C3, and C5. However, sheep erythrocytes (SRC) coated with Agg-R/A-IgG or with reduced and alkylated rabbit IgG anti-SRC antibody were hemolyzed by complement in the presence of polyclonal IgM-RF. Human and guinea pig complement worked equally well. The degree of hemolysis was in direct proportion to the hemagglutination titer of the RF against the same coated cells. Monoclonal IgM-RF, normal human IgM, and purified Waldenström macroglobulins without antiglobulin activity were all inert. Hemolysis of coated SRC by RF and complement was inhibited by prior treatment of the complement source with chelating agents, hydrazine, cobra venom factor, specific antisera to C1q, CR, C5, C6, or C8, or by heating at 56 degrees C for 30 min. Purified radiolabeled C4, C3, and C8 included in the complement source were bound to hemolysed SRC in direct proportion to the degree of hemolysis. These data indicate that polyclonal IgM-RF fix and activate complement via the classic pathway. The system described for assessing complement fixation by isolated RF is readily adaptable to use with whole human serum. PMID:1078825

  15. Functional ecology of free-living nitrogen fixation: A contemporary perspective

    USGS Publications Warehouse

    Reed, Sasha C.; Cleveland, Cory C.; Townsend, Alan R.

    2011-01-01

    Nitrogen (N) availability is thought to frequently limit terrestrial ecosystem processes, and explicit consideration of N biogeochemistry, including biological N2 fixation, is central to understanding ecosystem responses to environmental change. Yet, the importance of free-living N2 fixation—a process that occurs on a wide variety of substrates, is nearly ubiquitous in terrestrial ecosystems, and may often represent the dominant pathway for acquiring newly available N—is often underappreciated. Here, we draw from studies that investigate free-living N2 fixation from functional, physiological, genetic, and ecological perspectives. We show that recent research and analytical advances have generated a wealth of new information that provides novel insight into the ecology of N2 fixation as well as raises new questions and priorities for future work. These priorities include a need to better integrate free-living N2 fixation into conceptual and analytical evaluations of the N cycle's role in a variety of global change scenarios.

  16. Early Experience with Biodegradable Fixation of Pediatric Mandibular Fractures.

    PubMed

    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. PMID:26269728

  17. Dorsal Buttress Plate Fixation of Ulnar Carpometacarpal Joint Fracture Dislocations.

    PubMed

    Tan, En Si; Chao, Tay Shian

    2016-06-01

    We propose a method for open reduction and internal fixation of early and unstable ulnar (fourth and/or fifth) carpometacarpal joint (CMCJ) fracture subluxations or dislocations using a dorsal buttress plate. In ulnar CMCJ fracture dislocations, the metacarpal has a tendency to displace dorsally and proximally when there is an axial load. Using the dorsal buttress plate method of fixation, a plate is fixed proximally to the hamate, aligned parallel and dorsal to the metacarpal to act as a buttress, to resist this movement. To preserve the fourth and the fifth CMCJ mobility, the distal end of the plate is not fixed to the metacarpal base. We illustrate the use of this technique on 4 patients who had different patterns of injury at the ulnar CMCJ. All patients regained excellent range of motion and function. None of the patients had redisplacement or nonunion of fracture. The dorsal buttress plate is a viable option for fixation of early and unstable ulnar CMCJ fracture subluxations or dislocations. PMID:27077465

  18. Salient in space, salient in time: Fixation probability predicts fixation duration during natural scene viewing.

    PubMed

    Einhäuser, Wolfgang; Nuthmann, Antje

    2016-09-01

    During natural scene viewing, humans typically attend and fixate selected locations for about 200-400 ms. Two variables characterize such "overt" attention: the probability of a location being fixated, and the fixation's duration. Both variables have been widely researched, but little is known about their relation. We use a two-step approach to investigate the relation between fixation probability and duration. In the first step, we use a large corpus of fixation data. We demonstrate that fixation probability (empirical salience) predicts fixation duration across different observers and tasks. Linear mixed-effects modeling shows that this relation is explained neither by joint dependencies on simple image features (luminance, contrast, edge density) nor by spatial biases (central bias). In the second step, we experimentally manipulate some of these features. We find that fixation probability from the corpus data still predicts fixation duration for this new set of experimental data. This holds even if stimuli are deprived of low-level images features, as long as higher level scene structure remains intact. Together, this shows a robust relation between fixation duration and probability, which does not depend on simple image features. Moreover, the study exemplifies the combination of empirical research on a large corpus of data with targeted experimental manipulations. PMID:27627736

  19. Immaturity of Visual Fixations in Dyslexic Children

    PubMed Central

    Tiadi, Aimé; Gérard, Christophe-Loïc; Peyre, Hugo; Bui-Quoc, Emmanuel; Bucci, Maria Pia

    2016-01-01

    To our knowledge, behavioral studies recording visual fixations abilities in dyslexic children are scarce. The object of this article is to explore further the visual fixation ability in dyslexics compared to chronological age-matched and reading age-matched non-dyslexic children. Fifty-five dyslexic children from 7 to 14 years old, 55 chronological age-matched non-dyslexic children and 55 reading age-matched non-dyslexic children participated to this study. Eye movements from both eyes were recorded horizontally and vertically by a video-oculography system (EyeBrain® T2). The fixation task consisted in fixating a white-filled circle appearing in the center of the screen for 30 s. Results showed that dyslexic children produced a significantly higher number of unwanted saccades than both groups of non-dyslexic children. Moreover, the number of unwanted saccades significantly decreased with age in both groups of non-dyslexic children, but not in dyslexics. Furthermore, dyslexics made more saccades during the last 15 s of fixation period with respect to both groups of non-dyslexic children. Such poor visual fixation capability in dyslexic children could be due to impaired attention abilities, as well as to an immaturity of the cortical areas controlling the fixation system. PMID:26924975

  20. Closed Reduction and Percutaneous Fixation of Calcaneal Fractures in Children.

    PubMed

    Feng, Yongzeng; Yu, Yang; Shui, Xiaolong; Ying, Xiaozhou; Cai, Leyi; Hong, Jianjun

    2016-07-01

    Open reduction and internal fixation has been widely used to treat displaced intra-articular calcaneus fractures in children. However, the complications of surgical trauma and the wound created through the extended lateral approach cannot be ignored. This study analyzed the outcomes of displaced intra-articular calcaneal fractures in children treated with closed reduction and percutaneous fixation. Medical records of pediatric patients who had displaced intra-articular calcaneus fractures and underwent closed reduction and percutaneous fixation at the study institution between January 2008 and January 2013 were reviewed. Preoperative radiographs and computed tomography scans were used to evaluate and classify the fractures. Clinical outcomes and radiographic findings were assessed at postoperative follow-up. The study included 14 displaced intra-articular calcaneal fractures in 11 patients (7 boys and 4 girls). Mean patient age was 11.18 years (range, 6-16 years), and average follow-up time was 42.8 months postoperatively (range, 12-72 months). There were 6 tongue-type fractures and 8 joint depression-type fractures, based on the Essex-Lopresti classification, and there were 11 type II and 3 type III fractures, based on the Sanders classification. Average Böhler angle was 8.00° (range, -5° to 18°) preoperatively and 30.79° (range, 26° to 40°) postoperatively (P<.001). Average subjective American Orthopaedic Foot and Ankle Society hindfoot score was 65.7 (range, 52-68). No patients had wound breakdown or infection. In the treatment of displaced intra-articular calcaneal fractures in pediatric patients, closed reduction and percutaneous fixation achieved good outcomes, with few complications. [Orthopedics. 2016; 39(4):e744-e748.]. PMID:27111072

  1. [Histologic finding of fracture healing using external fixation and its clinical significance].

    PubMed

    Stürmer, K M

    1984-06-01

    The histology of bone healing under external fixation of fractures is studied in 2 human bone specimen and in the sheep's tibia. Primary bone healing occurs under absolute stable fixation. The regular course shows secundary bone healing by endosteal and periosteal callus formation, caused by motion in the fracture gap. Nonunion results, if motion is not big enough to induce callus formation and if motion is too big to allow primary bone healing. So one of the main problems in external fixation of fractures is to find out the adequate dose of stability and motion in the fracture gap. External fixation does not disturb the vascular supply of bone. Intramedullary vessels, that are cut during the osteotomy of the sheep's tibia, are perfectly regenerated 4-5 weeks later. In the surroundings of the Schanz' screws, cortical remodelling is the biomechanical response of bone to strees, which is generated by external fixation. This cortical remodelling can reduce compression, originally applied to the bone. The indication and the timing for a change to internal fixation is discussed. PMID:6474602

  2. Arthroscopic fixation of type III acromioclavicular dislocations.

    PubMed

    Somers, Jan F A; Van der Linden, Dietert

    2007-10-01

    Type III Acromio-Clavicular Joint dislocations can be treated successfully by surgical stabilisation in situ, with or without reconstruction of the coracoclavicular ligaments. The authors describe a simple and reliable mode of fixation, performed arthroscopically. The technique can be used for in situ fixation, or as part of an arthroscopically assisted Weaver and Dunn procedure. Using a metallic anchor loaded with a braided polyfilament suture, a strong and reliable fixation of the clavicle to the coracoid process is obtained. No hardware removal is necessary. Concomitant glenohumeral pathology can be treated simultaneously. PMID:18019910

  3. Seasonal patterns of periphyton nitrogen fixation in calcareous wetlands

    NASA Astrophysics Data System (ADS)

    Liao, X.; Inglett, P.

    2011-12-01

    Periphyton mats are an ecologically important component of the Everglades ecosystem and plays various vital ecological functions. However, nitrogen fixation of periphyton, has received little attention throughout much of the Everglades system. The objective of this study was to characterize the seasonal pattern of periphyton N2 fixation in the Hole-in-the-Donut (HID) of Florida Everglades, where farmed marl prairie wetlands have been restored through complete soil removal (CSR) to reduce nutrient levels. Two restored areas (i.e., cleared in 2000 and 2003) and a reference (natural and unfarmed) marl prairie wetland sites were selected in the HID. Seven times of sampling were performed across the wet and dry season during the 2010 and 2011. The annual fixed nitrogen was approximately 0.4gN m-2 yr-1 in the restored sites which was higher in the reference site (~0.2gN m-2 yr-1). All the three sites showed similar seasonal patterns of N2 fixation that is higher values were observed in the wet season; but the peak value was one month later in reference sits (i.e., September) comparing to the restored areas (i.e., July). The peak of periphyton AR rates in the 2000- and 2003-restored areas appeared in July (i.e., wet season) within the range of 20-79 nmols g-1dw h-1 and 31-53nmols g-1dw h-1, respectively. In contrast, the peak of reference site was observed in September with the range of 2-5 nmols g-1dw h-1. Stable N isotopic ratios (i.e., δ15N) also varied with time but didn't show consistent seasonal pattern as nitrogen fixation. N2 fixation positively correlated with periphyton total phosphorus (TP) and negatively correlated with total nitrogen and phosphorus molar ratios (TN:TP), indicating that N2 fixation would be a indicator of nutrient limitation. In general, δ15N was negatively correlated with nitrogenase activity but the correlation became weakened in the wet season, especially in the flooded July and September, which would be explained by other environmental

  4. 76 FR 19517 - Orders Limiting Scheduled Operations at John F. Kennedy International Airport, LaGuardia Airport...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-07

    ....\\1\\ \\1\\ 75 FR 9017 (Feb. 26, 2010). ATA also stated the National Oceanic and Atmospheric...\\ 14 CFR 93.227 (DCA); 74 FR 51648 (Oct. 7, 2009) (EWR); 74 FR 51650 (Oct. 7, 2009) (JFK); 74 FR 51653... Airport, LaGuardia Airport, and Newark Liberty International Airport; High Density Rule at Reagan...

  5. 77 FR 68196 - Orders Limiting Operations at John F. Kennedy International Airport, LaGuardia Airport, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-15

    ... CFR 93.227 (DCA); 74 FR 51648 (Oct. 7, 2009) (EWR); 74 FR 51650 (Oct. 7, 2009) (JFK); 77 FR 30585 (May...Guardia Airport, and Newark Liberty International Airport; High Density Rule at Reagan Washington National... operations took several days after the storm. FAA Analysis Under the FAA's High Density Rule at DCA...

  6. Improving the Early Literacy Skills of Students at Risk for Internalizing or Externalizing Behaviors with Limited Reading Skills

    ERIC Educational Resources Information Center

    Harris, Pamela J.; Oakes, Wendy Peia; Lane, Kathleen Lynne; Rutherford, Robert B., Jr.

    2009-01-01

    Eight first-grade students with either internalizing or externalizing behavioral risk factors participated in a supplemental reading intervention for 30 min per day. The intervention package consisted of three main components: instruction in word recognition, fluency, and appropriate behavior. A multiple-baseline design was employed to assess…

  7. Complications of Absorbable Fixation in Maxillofacial Surgery: A Meta-Analysis

    PubMed Central

    Yang, Liya; Xu, Meibang; Jin, Xiaolei; Xu, Jiajie; Lu, Jianjian; Zhang, Chao; Tian, Tian; Teng, Li

    2013-01-01

    Background The use of titanium during maxillofacial fixation is limited due to its palpability, mutagenic effects and interference with imaging, which lead to the requirement for subsequent removal. The use of a biologically absorbable fixation material will potentially eliminate these limitations. In this meta-analysis, we analyzed the complications of absorbable fixation in maxillofacial surgery. Methods We performed a systematic search of PubMed, Embase, Cochrane Central Register of Systematic Reviews and Cochrane Central Register of Controlled Trials for trials published through December 2012. Data extracted from literature were analyzed with Review manager 5.0.24. Results Relevant data was extracted from 20 studies (1673 participants) and revealed that patients in the absorbable group had significantly more complications than those in the titanium group (RR = 1.20; 95% CI: 1.02–1.42; P = 0.03) in all enrolled maxillofacial surgeries. For bimaxillary operation subgroup, the absorbable fixation group did not have a significant increase in complications when compared with the titanium group (RR = 1.89; 95% CI: 0.85–4.22; P = 0.12). There was no significant difference observed between the absorbable and titanium groups receiving a bilateral sagittal split ramus osteotomy (BSSRO) (RR = 1.45; 95% CI: 0.84–2.48; P = 0.18) and Le Fort I osteotomy (RR = 0.65; 95% CI: 0.34–1.23; P = 0.18). The combined results of the five trials revealed that the absorbable group had a significantly lower rate of complications compared to the titanium group (RR = 0.71; 95% CI: 0.52–0.97; P = 0.03) in fracture fixation. Conclusion This meta-analysis shows that absorbable fixation systems used for fixation in maxillofacial surgery do not have adequate safety profiles. Subgroup indicated the safety of absorbable fixation systems was superior during fracture fixation. The absorbable fixation systems tend to have a similar favorable safety

  8. Nitrogen Fixation Tolerance to Soil Water Deficit Among Commercial Cultivars and breeding Lines of Peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peanut is often grown in the U.S. on sandy soil with limited water holding capacity. Since nitrogen fixation activity of other grain legume species, and some peanut cultivars, has been found to be especially sensitive to soil drying, this study was undertaken to examine a possible limitation in U.S...

  9. A simple method of intramedullary fixation for proximal interphalangeal arthrodesis.

    PubMed

    Canales, Michael B; Razzante, Mark C; Ehredt, Duane J; Clougherty, Coleman O

    2014-01-01

    Lesser digital arthrodesis has become one of the most widely used techniques in foot and ankle surgery. When performing digital arthrodesis, surgeons have an abundance of options for implantable devices. We provide information on a simple method of achieving successful arthrodesis. An intramedullary Kirschner wire is implanted into the proximal phalanx with the intermediate phalanx compressed over the wire for rigid internal fixation to avoid the use of an external device. We have had results similar to those from the published data of more expensive implants. PMID:24846156

  10. Scaphoid Fracture Fixation with an Acutrak(®) Screw.

    PubMed

    Loving, Vilert A; Richardson, Michael L

    2006-01-01

    We report a case of fixation of a scaphoid fracture using an Acutrak(®) screw. This screw is cannulated and headless, which allows it to be implanted below the surface of the bone. It uses the same concept of variable thread pitch as the Herbert screw, but unlike the Herbert screw, is fully threaded, with continuously varying pitch along its length. This variable pitch creates constant compression across a fracture as the screw is advanced, and gives the screw its unique appearance. This feature may improve internal holding power, as well as allow a fracture or osteotomy site to lie anywhere along the length of the screw. PMID:27298683

  11. Amputated Lower Limb Fixation to the Fracture Table.

    PubMed

    Gamulin, Axel; Farshad, Mazda

    2015-11-01

    Fractures of the proximal and diaphyseal femur are frequently internally fixed using a fracture table with fracture reduction obtained by traction and adequate rotation exerted on the slightly abducted extremity. Although rare, these fractures may occur on an amputated limb. If so, standard use of a fracture table is not possible. To address this situation, the authors describe a simple novel technique allowing rigid fixation of the amputated limb to the traction device of the fracture table that provides accurate control of reduction in all planes. PMID:26558660

  12. Neural correlates of fixation duration in natural reading: Evidence from fixation-related fMRI.

    PubMed

    Henderson, John M; Choi, Wonil; Luke, Steven G; Desai, Rutvik H

    2015-10-01

    A key assumption of current theories of natural reading is that fixation duration reflects underlying attentional, language, and cognitive processes associated with text comprehension. The neurocognitive correlates of this relationship are currently unknown. To investigate this relationship, we compared neural activation associated with fixation duration in passage reading and a pseudo-reading control condition. The results showed that fixation duration was associated with activation in oculomotor and language areas during text reading. Fixation duration during pseudo-reading, on the other hand, showed greater involvement of frontal control regions, suggesting flexibility and task dependency of the eye movement network. Consistent with current models, these results provide support for the hypothesis that fixation duration in reading reflects attentional engagement and language processing. The results also demonstrate that fixation-related fMRI provides a method for investigating the neurocognitive bases of natural reading. PMID:26151101

  13. Transcriptional profiling of nitrogen fixation in Azotobacter vinelandii.

    PubMed

    Hamilton, Trinity L; Ludwig, Marcus; Dixon, Ray; Boyd, Eric S; Dos Santos, Patricia C; Setubal, João C; Bryant, Donald A; Dean, Dennis R; Peters, John W

    2011-09-01

    Most biological nitrogen (N(2)) fixation results from the activity of a molybdenum-dependent nitrogenase, a complex iron-sulfur enzyme found associated with a diversity of bacteria and some methanogenic archaea. Azotobacter vinelandii, an obligate aerobe, fixes nitrogen via the oxygen-sensitive Mo nitrogenase but is also able to fix nitrogen through the activities of genetically distinct alternative forms of nitrogenase designated the Vnf and Anf systems when Mo is limiting. The Vnf system appears to replace Mo with V, and the Anf system is thought to contain Fe as the only transition metal within the respective active site metallocofactors. Prior genetic analyses suggest that a number of nif-encoded components are involved in the Vnf and Anf systems. Genome-wide transcription profiling of A. vinelandii cultured under nitrogen-fixing conditions under various metal amendments (e.g., Mo or V) revealed the discrete complement of genes associated with each nitrogenase system and the extent of cross talk between the systems. In addition, changes in transcript levels of genes not directly involved in N(2) fixation provided insight into the integration of central metabolic processes and the oxygen-sensitive process of N(2) fixation in this obligate aerobe. The results underscored significant differences between Mo-dependent and Mo-independent diazotrophic growth that highlight the significant advantages of diazotrophic growth in the presence of Mo. PMID:21724999

  14. Ocular Fixation Abnormality in Patients with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Shirama, Aya; Kanai, Chieko; Kato, Nobumasa; Kashino, Makio

    2016-01-01

    We examined the factors that influence ocular fixation control in adults with autism spectrum disorder (ASD) including sensory information, individuals' motor characteristics, and inhibitory control. The ASD group showed difficulty in maintaining fixation especially when there was no fixation target. The fixational eye movement characteristics of…

  15. Tibial rotational osteotomy with intramedullary nail fixation

    PubMed Central

    Stevens, Peter M.

    2009-01-01

    There are several theoretic advantages of using intramedullary rod fixation for tibial osteotomy fixation. We performed a retrospective review of patients who were treated with a mid-diaphyseal osteotomy of the tibia fixed with an intramedullary rod for isolated, symptomatic tibial torsion. Forty patients (59 tibias) were included in the study and were followed for a minimum of 12 months or until rod removal (average follow-up 22.6 months). Major complication rate was 8.5%, which is comparable to alternative methods of fixation. We believe that intramedullary rods are a safe alternative for fixation of tibial rotational osteotomy in patients with physeal closure. PMID:19941168

  16. A simple and inexpensive external fixator.

    PubMed

    Noor, M A

    1988-11-01

    A simple and inexpensive external fixator has been designed. It is constructed of galvanized iron pipe and mild steel bolts and nuts. It can easily be manufactured in a hospital workshop with a minimum of tools. PMID:3267638

  17. Recurrent carpal tunnel syndrome, epineural fibrous fixation, and traction neuropathy.

    PubMed

    Hunter, J M

    1991-08-01

    This article has reviewed recurrent carpal tunnel syndrome, epineural fibrous fixation, and traction neuropathy of the median nerve. The problems surrounding the diagnosis and treatment of recurrent CTS have been discussed at length. The percent of failures from traditional open ligament surgery is observed to be high, and will become more prevalent as more casual treatments are carried out. This article makes a positive statement with reference to mobilization of the median nerve and anatomic restoration of the transverse carpal ligament. Fibrous fixation of the median nerve is a product of life and function. All cases are different, reflecting the strength, abilities, and personalities of the patients. A bottom line is drawn on these patients, where the summation of the problems of life become symptomatic and disabling. Epineural fibrous fixations induce median nerve traction, governed by hand, wrist, and forearm movements. Traction and tension suggest the intermittent disturbance of nerve nutrition and nerve conduction as the elastic limits of the nerve are approached. These factors accumulate and, in time, cause traction neuropathies with pain. This is followed by a reduced work capability. This impairment can be reversed by surgical nerve mobilization followed by functional nerve gliding therapy. A background history injury to the hand and wrist may be significant, as well as factors such as overuse and misuse of the hand and extremity. Prior to surgery, the careful application of diagnostic stress tests are essential, for the differential diagnosis of fixation traction and positional peripheral neuropathies. Nerve mobilization supported by magnification and the techniques of hand surgery has been successful by the methods discussed and has permitted, importantly, the restoration of the anatomic retinaculum for the flexor tendon system. This can be restored in carpal tunnel surgery and reconstructed with basic ligament material in recurrent carpal tunnel

  18. Tamponade following sternoclavicular dislocation surgical fixation.

    PubMed

    Bensafi, H; Laffosse, J-M; Taam, S A; Molinier, F; Chaminade, B; Puget, J

    2010-05-01

    The authors report a case of posterior sternoclavicular dislocation surgically reduced and stabilized with tenodesis, according to the Burrows technique completed by temporary wire fixation. The patient presented postoperative pericardiac tamponade appearing progressively from brachiocephalic blood vessels bleeding. Emergency drainage was surgically placed associated with removal of the material, thus curing the patient. This complication, although exceptional, formally contraindicates the use of wire fixation in surgery of the sternoclavicular joint. PMID:20488152

  19. Tips and Tricks in Mallet Fracture Fixation.

    PubMed

    Chin, Yuin Cheng; Foo, Tun-Lin

    2016-10-01

    We describe three steps to aid fracture assessment and fixation in the extensor block pin technique for mallet fractures. The first step is the use of fluoroscopy in the initial assessment to determine indication for fixation. Next is the use of supplementary extension block pin to control larger dorsal fragments. The third technique described details the steps of open reduction of nascently malunited fractures. PMID:27595969

  20. Effects of prolonged formalin fixation on diagnostic immunohistochemistry in domestic animals.

    PubMed

    Webster, Joshua D; Miller, Margaret A; Dusold, Dee; Ramos-Vara, José

    2009-08-01

    Immunohistochemistry (IHC) is routinely used in diagnostic pathology to detect infectious agents, to immunophenotype neoplastic cells, and to prognosticate neoplastic diseases. Formalin fixation is considered a limiting factor for IHC because formalin can cross-link antigens and mask epitopes. Prolonged formalin fixation is presumed to result in decreased antigen detection; however, this effect has only been evaluated with a few antibodies. The goal of this study was to evaluate the effect of prolonged formalin fixation on the immunohistochemical detection of 61 different antigens. Approximately 5-mm-thick tissue slices were fixed in 10% neutral-buffered formalin. Tissue slices were removed from formalin, processed, and paraffin-embedded at 1-day, 3-day, and then at approximately 1-week intervals. IHC was performed on all sections in tandem after all tissues were processed. Immunoreactions were evaluated by three pathologists according to a four-tier grading system. Immunoreactivity of cytokeratin 7, high-molecular-weight cytokeratin, and laminin was diminished by prolonged formalin fixation. However, immunohistochemical reactivity remained moderate to strong with up to 7 weeks of fixation for all other antibodies. These results suggest that prolonged formalin fixation has minimal effects on antigen detection for most commonly used antibodies. These results further validate the use of IHC in diagnostic pathology. PMID:19398606

  1. Shape modifications of porous hydroxyapatite prostheses to improve rigid implant fixation: Experience in 12 cases

    PubMed Central

    Rienzo, Alessandro Di; Iacoangeli, Maurizio; di Somma, Lucia G. M.; Alvaro, Lorenzo; Nocchi, Niccolò; Scerrati, Massimo

    2012-01-01

    Background: Various methods of fixation have been described for custom made hydroxyapatite cranial implants. Their poor malleability limits most of the common used fixation techniques because of the high risk of cranioplasty's fracturing or higher exposure to infections. We present our experience with a new fixation technique, based on an appositely premodified hydroxyapatite implants. Methods: In a 2-year time period, 12 patients underwent cranioplasty by a modified custom made porous hydroxyapatite implant. Once the three-dimensional computer model of the prostheses was performed, three semicircular extensions placed at strategic positions were drawn and the final prosthesis was realized. At surgery, holes fitting the extensions were drilled into the skull borders and the implant was easily embedded inside the defect. Small titanium meshes overlying the extensions were fixed by screws to the surrounding bone. Results: A minimal increase of operative times was recorded, with drilling and fixation requiring additional 30 and 15 minutes, respectively. Optimal contact between cranioplasty and skull borders was always observed at control computed tomography (CT) scans. Permanent rigid fixation was obtained in all cases, with good functional and aesthetic results at follow-up. Conclusions: Modifications of hydroxyapatite implants are obtained without additional costs. The minimal increase of operative times is largely counterbalanced by optimal fixation results. Finally, the bone drilling and the immediate proximity of bone to prosthesis might enhance the potential for osteogenesis and osteointegration. PMID:23372977

  2. Biotic nitrogen fixation in the bryosphere is inhibited more by drought than warming.

    PubMed

    Whiteley, Jonathan A; Gonzalez, Andrew

    2016-08-01

    The boreal forest is of particular interest to climate change research due to its large circumpolar distribution and accumulated soil carbon pool. Carbon uptake in this ecosystem is nitrogen (N)-limited, therefore factors affecting carbon or nitrogen dynamics in the boreal forest can have consequences for global climate. We used a 2-year field experiment to investigate the response of biotic nitrogen fixation by cyanobacteria associated with boreal forest bryophytes, in a factorial experiment combining simulated climate change with habitat fragmentation treatments. We simulated climate change conditions using open-top greenhouse chambers in the field, which increased mean and maximum temperatures, and created a precipitation gradient from ambient levels in the center to extreme drought conditions at the periphery of the chamber. The dry patches near the chamber walls exhibited almost no N-fixation, despite having similar densities of cyanobacteria (predominantly Stigonema sp.) as other patches. Rates of N-fixation were best explained by a model containing moisture, fragmentation, cyanobacteria density and time; warming was not a significant variable affecting N-fixation. There was no significant interaction between warming and fragmentation. These results suggest that cyanobacteria responded physiologically to drought by reducing N-fixation activity long before any changes in density. Ecosystem processes, such as N-fixation, can respond in the short term to environmental change much more rapidly than changes in the underlying community structure. Such rapid physiological responses may occur faster than demographic insurance effects of biodiversity. PMID:27098528

  3. Symbiotic Nitrogen Fixation and the Challenges to Its Extension to Nonlegumes

    PubMed Central

    Mus, Florence; Crook, Matthew B.; Garcia, Kevin; Garcia Costas, Amaya; Geddes, Barney A.; Kouri, Evangelia D.; Paramasivan, Ponraj; Ryu, Min-Hyung; Oldroyd, Giles E. D.; Poole, Philip S.; Udvardi, Michael K.; Voigt, Christopher A.

    2016-01-01

    Access to fixed or available forms of nitrogen limits the productivity of crop plants and thus food production. Nitrogenous fertilizer production currently represents a significant expense for the efficient growth of various crops in the developed world. There are significant potential gains to be had from reducing dependence on nitrogenous fertilizers in agriculture in the developed world and in developing countries, and there is significant interest in research on biological nitrogen fixation and prospects for increasing its importance in an agricultural setting. Biological nitrogen fixation is the conversion of atmospheric N2 to NH3, a form that can be used by plants. However, the process is restricted to bacteria and archaea and does not occur in eukaryotes. Symbiotic nitrogen fixation is part of a mutualistic relationship in which plants provide a niche and fixed carbon to bacteria in exchange for fixed nitrogen. This process is restricted mainly to legumes in agricultural systems, and there is considerable interest in exploring whether similar symbioses can be developed in nonlegumes, which produce the bulk of human food. We are at a juncture at which the fundamental understanding of biological nitrogen fixation has matured to a level that we can think about engineering symbiotic relationships using synthetic biology approaches. This minireview highlights the fundamental advances in our understanding of biological nitrogen fixation in the context of a blueprint for expanding symbiotic nitrogen fixation to a greater diversity of crop plants through synthetic biology. PMID:27084023

  4. Symbiotic Nitrogen Fixation and the Challenges to Its Extension to Nonlegumes.

    PubMed

    Mus, Florence; Crook, Matthew B; Garcia, Kevin; Garcia Costas, Amaya; Geddes, Barney A; Kouri, Evangelia D; Paramasivan, Ponraj; Ryu, Min-Hyung; Oldroyd, Giles E D; Poole, Philip S; Udvardi, Michael K; Voigt, Christopher A; Ané, Jean-Michel; Peters, John W

    2016-07-01

    Access to fixed or available forms of nitrogen limits the productivity of crop plants and thus food production. Nitrogenous fertilizer production currently represents a significant expense for the efficient growth of various crops in the developed world. There are significant potential gains to be had from reducing dependence on nitrogenous fertilizers in agriculture in the developed world and in developing countries, and there is significant interest in research on biological nitrogen fixation and prospects for increasing its importance in an agricultural setting. Biological nitrogen fixation is the conversion of atmospheric N2 to NH3, a form that can be used by plants. However, the process is restricted to bacteria and archaea and does not occur in eukaryotes. Symbiotic nitrogen fixation is part of a mutualistic relationship in which plants provide a niche and fixed carbon to bacteria in exchange for fixed nitrogen. This process is restricted mainly to legumes in agricultural systems, and there is considerable interest in exploring whether similar symbioses can be developed in nonlegumes, which produce the bulk of human food. We are at a juncture at which the fundamental understanding of biological nitrogen fixation has matured to a level that we can think about engineering symbiotic relationships using synthetic biology approaches. This minireview highlights the fundamental advances in our understanding of biological nitrogen fixation in the context of a blueprint for expanding symbiotic nitrogen fixation to a greater diversity of crop plants through synthetic biology. PMID:27084023

  5. Fixational eye movements predict visual sensitivity.

    PubMed

    Scholes, Chris; McGraw, Paul V; Nyström, Marcus; Roach, Neil W

    2015-10-22

    During steady fixation, observers make small fixational saccades at a rate of around 1-2 per second. Presentation of a visual stimulus triggers a biphasic modulation in fixational saccade rate-an initial inhibition followed by a period of elevated rate and a subsequent return to baseline. Here we show that, during passive viewing, this rate signature is highly sensitive to small changes in stimulus contrast. By training a linear support vector machine to classify trials in which a stimulus is either present or absent, we directly compared the contrast sensitivity of fixational eye movements with individuals' psychophysical judgements. Classification accuracy closely matched psychophysical performance, and predicted individuals' threshold estimates with less bias and overall error than those obtained using specific features of the signature. Performance of the classifier was robust to changes in the training set (novel subjects and/or contrasts) and good prediction accuracy was obtained with a practicable number of trials. Our results indicate a tight coupling between the sensitivity of visual perceptual judgements and fixational eye control mechanisms. This raises the possibility that fixational saccades could provide a novel and objective means of estimating visual contrast sensitivity without the need for observers to make any explicit judgement. PMID:26468244

  6. Maxwellian Eye Fixation during Natural Scene Perception

    PubMed Central

    Duchesne, Jean; Bouvier, Vincent; Guillemé, Julien; Coubard, Olivier A.

    2012-01-01

    When we explore a visual scene, our eyes make saccades to jump rapidly from one area to another and fixate regions of interest to extract useful information. While the role of fixation eye movements in vision has been widely studied, their random nature has been a hitherto neglected issue. Here we conducted two experiments to examine the Maxwellian nature of eye movements during fixation. In Experiment 1, eight participants were asked to perform free viewing of natural scenes displayed on a computer screen while their eye movements were recorded. For each participant, the probability density function (PDF) of eye movement amplitude during fixation obeyed the law established by Maxwell for describing molecule velocity in gas. Only the mean amplitude of eye movements varied with expertise, which was lower in experts than novice participants. In Experiment 2, two participants underwent fixed time, free viewing of natural scenes and of their scrambled version while their eye movements were recorded. Again, the PDF of eye movement amplitude during fixation obeyed Maxwell's law for each participant and for each scene condition (normal or scrambled). The results suggest that eye fixation during natural scene perception describes a random motion regardless of top-down or of bottom-up processes. PMID:23226987

  7. Maxwellian eye fixation during natural scene perception.

    PubMed

    Duchesne, Jean; Bouvier, Vincent; Guillemé, Julien; Coubard, Olivier A

    2012-01-01

    When we explore a visual scene, our eyes make saccades to jump rapidly from one area to another and fixate regions of interest to extract useful information. While the role of fixation eye movements in vision has been widely studied, their random nature has been a hitherto neglected issue. Here we conducted two experiments to examine the Maxwellian nature of eye movements during fixation. In Experiment 1, eight participants were asked to perform free viewing of natural scenes displayed on a computer screen while their eye movements were recorded. For each participant, the probability density function (PDF) of eye movement amplitude during fixation obeyed the law established by Maxwell for describing molecule velocity in gas. Only the mean amplitude of eye movements varied with expertise, which was lower in experts than novice participants. In Experiment 2, two participants underwent fixed time, free viewing of natural scenes and of their scrambled version while their eye movements were recorded. Again, the PDF of eye movement amplitude during fixation obeyed Maxwell's law for each participant and for each scene condition (normal or scrambled). The results suggest that eye fixation during natural scene perception describes a random motion regardless of top-down or of bottom-up processes. PMID:23226987

  8. Variable Nitrogen Fixation in Wild Populus.

    PubMed

    Doty, Sharon L; Sher, Andrew W; Fleck, Neil D; Khorasani, Mahsa; Bumgarner, Roger E; Khan, Zareen; Ko, Andrew W K; Kim, Soo-Hyung; DeLuca, Thomas H

    2016-01-01

    The microbiome of plants is diverse, and like that of animals, is important for overall health and nutrient acquisition. In legumes and actinorhizal plants, a portion of essential nitrogen (N) is obtained through symbiosis with nodule-inhabiting, N2-fixing microorganisms. However, a variety of non-nodulating plant species can also thrive in natural, low-N settings. Some of these species may rely on endophytes, microorganisms that live within plants, to fix N2 gas into usable forms. Here we report the first direct evidence of N2 fixation in the early successional wild tree, Populus trichocarpa, a non-leguminous tree, from its native riparian habitat. In order to measure N2 fixation, surface-sterilized cuttings of wild poplar were assayed using both 15N2 incorporation and the commonly used acetylene reduction assay. The 15N label was incorporated at high levels in a subset of cuttings, suggesting a high level of N-fixation. Similarly, acetylene was reduced to ethylene in some samples. The microbiota of the cuttings was highly variable, both in numbers of cultured bacteria and in genetic diversity. Our results indicated that associative N2-fixation occurred within wild poplar and that a non-uniformity in the distribution of endophytic bacteria may explain the variability in N-fixation activity. These results point to the need for molecular studies to decipher the required microbial consortia and conditions for effective endophytic N2-fixation in trees. PMID:27196608

  9. Variable Nitrogen Fixation in Wild Populus

    PubMed Central

    Doty, Sharon L.; Sher, Andrew W.; Fleck, Neil D.; Khorasani, Mahsa; Bumgarner, Roger E.; Khan, Zareen; Ko, Andrew W. K.; Kim, Soo-Hyung; DeLuca, Thomas H.

    2016-01-01

    The microbiome of plants is diverse, and like that of animals, is important for overall health and nutrient acquisition. In legumes and actinorhizal plants, a portion of essential nitrogen (N) is obtained through symbiosis with nodule-inhabiting, N2-fixing microorganisms. However, a variety of non-nodulating plant species can also thrive in natural, low-N settings. Some of these species may rely on endophytes, microorganisms that live within plants, to fix N2 gas into usable forms. Here we report the first direct evidence of N2 fixation in the early successional wild tree, Populus trichocarpa, a non-leguminous tree, from its native riparian habitat. In order to measure N2 fixation, surface-sterilized cuttings of wild poplar were assayed using both 15N2 incorporation and the commonly used acetylene reduction assay. The 15N label was incorporated at high levels in a subset of cuttings, suggesting a high level of N-fixation. Similarly, acetylene was reduced to ethylene in some samples. The microbiota of the cuttings was highly variable, both in numbers of cultured bacteria and in genetic diversity. Our results indicated that associative N2-fixation occurred within wild poplar and that a non-uniformity in the distribution of endophytic bacteria may explain the variability in N-fixation activity. These results point to the need for molecular studies to decipher the required microbial consortia and conditions for effective endophytic N2-fixation in trees. PMID:27196608

  10. WRIST ARTHRODESIS WITH MINIMAL FIXATION PRESERVING THE CARPOMETACARPAL JOINTS

    PubMed Central

    Pardini, Arlindo Gomes; Pádua Gonçalves, Rodolfo Fonseca; Freitas, Afrânio Donato; Chaves, Antonio Barbosa

    2015-01-01

    Objective: Wrist arthrodesis is a surgical procedure that should always be considered in cases of pathological conditions in which anatomical and functional structures are altered. In general, the results are very satisfactory, particularly for pain relief, and in the majority of cases, there is considerable functional improvement. Various techniques have been described, with different methods of internal fixation, most of which include the carpometacarpal joints in the fusion. The objective of this study was to evaluate the results from wrist arthrodesis using a technique that is simpler, more biological, less expensive, and does not involve the carpometacarpal joints. Methods: Fifteen patients with wrist arthrodesis were evaluated (six with sequelae from trauma, four with rheumatoid arthritis, three with Kienbock grade IV, one with Preiser and one with panarthrosis). The technique consisted of using an iliac bone plate and internal fixation with Kirschner wires, avoiding the carpometacarpal joints. Results: The evaluation was based on consolidation time (93% in seven weeks); movements of the fingers and pronosupination; pinch and grasp strength; functional evaluation through the DASH, pain and patient satisfaction questionnaires. In general, the results were similar to those of other, more aggressive techniques, and the non-inclusion of the carpometacarpal joints did not affect the final result. Conclusion: Wrist arthrodesis with fixation using Kirschner wires and an iliac bone plate, preserving the carpometacarpal joints, gives good or excellent results that are not inferior to those of other techniques that have been described. However, it presents major advantages over other methods: it is less aggressive and cheaper, and does not have the inconvenience and complications associated with the use of plates and screws. PMID:27022522

  11. The limits of crop productivity

    NASA Technical Reports Server (NTRS)

    Bugbee, Bruce; Monje, Oscar

    1992-01-01

    The component processes that govern yield limits in food crops are reviewed and how each process can be individually measured is described. The processes considered include absorption of photosynthetic radiation by green tissue, carbon-fixation efficiency in photosynthesis, carbon use efficiency in respiration, biomass allocation to edible products, and efficiency of photosynthesis and respiration. The factors limiting yields in optimal environments are considered.

  12. Nitrogen fixation and nitrogen transformations in marine symbioses.

    PubMed

    Fiore, Cara L; Jarett, Jessica K; Olson, Nathan D; Lesser, Michael P

    2010-10-01

    Many marine organisms have coevolved symbiotic relationships with nitrogen-fixing bacteria in nitrogen limited environments such as coral reefs. In addition, some of these organisms also harbor microbes that carry out nitrification and denitrification. Prokaryotes involved in nitrogen fixation and other nitrogen transformations are symbionts in a range of eukaryotic hosts in the marine environment including shipworms, diatoms, corals and sponges. Molecular genetic approaches, and other analytical techniques, have provided exciting new insights into symbiont diversity and the relationship between host and symbiont. We review the current state of knowledge of these symbioses and highlight important avenues for future studies. PMID:20674366

  13. Nitrogen Fixation in Denitrified Marine Waters

    PubMed Central

    Fernandez, Camila; Farías, Laura; Ulloa, Osvaldo

    2011-01-01

    Nitrogen fixation is an essential process that biologically transforms atmospheric dinitrogen gas to ammonia, therefore compensating for nitrogen losses occurring via denitrification and anammox. Currently, inputs and losses of nitrogen to the ocean resulting from these processes are thought to be spatially separated: nitrogen fixation takes place primarily in open ocean environments (mainly through diazotrophic cyanobacteria), whereas nitrogen losses occur in oxygen-depleted intermediate waters and sediments (mostly via denitrifying and anammox bacteria). Here we report on rates of nitrogen fixation obtained during two oceanographic cruises in 2005 and 2007 in the eastern tropical South Pacific (ETSP), a region characterized by the presence of coastal upwelling and a major permanent oxygen minimum zone (OMZ). Our results show significant rates of nitrogen fixation in the water column; however, integrated rates from the surface down to 120 m varied by ∼30 fold between cruises (7.5±4.6 versus 190±82.3 µmol m−2 d−1). Moreover, rates were measured down to 400 m depth in 2007, indicating that the contribution to the integrated rates of the subsurface oxygen-deficient layer was ∼5 times higher (574±294 µmol m−2 d−1) than the oxic euphotic layer (48±68 µmol m−2 d−1). Concurrent molecular measurements detected the dinitrogenase reductase gene nifH in surface and subsurface waters. Phylogenetic analysis of the nifH sequences showed the presence of a diverse diazotrophic community at the time of the highest measured nitrogen fixation rates. Our results thus demonstrate the occurrence of nitrogen fixation in nutrient-rich coastal upwelling systems and, importantly, within the underlying OMZ. They also suggest that nitrogen fixation is a widespread process that can sporadically provide a supplementary source of fixed nitrogen in these regions. PMID:21687726

  14. What is the potential for dark CO2 fixation in the facultative crassulacean acid metabolism species Talinum triangulare?

    PubMed

    Herrera, Ana; Ballestrini, Caín; Montes, Enrique

    2015-02-01

    In obligate Crassulacean acid metabolism (CAM) plants, dark CO2 fixation is almost the sole route of CO2 fixation and, under drought, continues for long periods. In contrast, in plants of the facultative CAM species Talinum triangulare under experimental drought, dark CO2 fixation provides a small proportion of the daily assimilation observed in watered plants and occurs only for a few days, after which almost nil CO2 fixation is observed. Under field conditions, with a practically unlimited substrate volume, drought-induced CAM might operate for a longer period and make a higher contribution to daily CO2 fixation. Greenhouse-grown plants of T. triangulare were subjected to low and nearly constant soil water content; the operation of CAM was assessed through the measurement of nocturnal proton accumulation and dark CO2 fixation. Dark CO2 fixation appeared 19d after the onset of drought; its contribution during three months of experiment to daily CO2 assimilation ranged from 0.5 to 30.7% with a mean of 13.5%. Twenty days after the beginning of treatment, nocturnal proton accumulation increased six times and remained high for over three months. In spite of low soil water content, leaves did not engage in dark CO2 fixation all the time but dark CO2 fixation was large enough to produce an increase in relative (13)C composition of mature leaves compared to watered plants but not to the value in short-term drought experiments. Leaf anatomical characteristics may guarantee the achievement of higher rates of dark CO2 fixation but results evidence the occurrence of a limit to the expression of CAM that remains to be determined. PMID:25462967

  15. Anatomic Anterolateral Ligament Reconstruction of the Knee Leads to Overconstraint at any Fixation Angle

    PubMed Central

    Schon, Jason; Brady, Alex; Moatshe, Gilbert; Cruz, Raphael; Chahla, Jorge; Dornan, Grant; Turnbull, Travis L.; Engebretsen, Lars

    2016-01-01

    Objectives: Anterior cruciate ligament (ACL) tears are one of the most common injuries among athletes. However, the ability to fully restore rotational stability with ACL reconstruction (ACLR) remains a challenge because up to 25% of patients may present with a residual pivot shift following surgery. Advocacy for reconstruction of the anterolateral ligament (ALL) is rapidly increasing because biomechanical studies have reported that the ALL is a significant contributor to internal rotational stability of the knee. Although several graft fixation angles for the anatomic ALL reconstruction (ALLR) have been reported in literature, none have been biomechanically validated. Therefore, the purpose of this study was to assess the effect of ALLR graft fixation angle on knee joint kinematics in the clinically relevant setting of a concomitant ACLR. The goal was to find the optimal knee flexion angle for fixation of the ALLR graft that would most accurately restore native knee kinematics without introducing overconstraint to the knee. It was hypothesized that all fixation angles would significantly reduce rotational laxity compared to the sectioned ALL state and that fixation at 30° would best reproduce native joint kinematics. Methods: Eight non-paired fresh-frozen human cadaveric knees with no prior injury, surgical history, or gross anatomic abnormality were evaluated with a 6 degree-of-freedom robotic system. Each specimen underwent a full kinematic assessment in each of the following states: 1) intact, 2) anatomic single-bundle (SB) ACLR with intact ALL, 3) anatomic SB ACLR with sectioned ALL, 4) 7 anatomic SB ACLR and ALLR states utilizing ALL graft fixation knee flexion angles of 0°, 15°, 30°, 45°, 60°, 75° and 90°, and 5) sectioned ACL and ALL. Internal rotation during a 5 N-m internal rotation torque and anterior displacement during an 88 N anterior load were recorded at 15° intervals between 0° and 120° of knee flexion. Axial plane displacement and

  16. One-stage posterior C2 and C3 pedicle screw fixation or combined anterior C2-C3 fusion for the treatment of unstable hangman’s fracture

    PubMed Central

    LIU, JINGCHEN; LI, YE; WU, YUNTAO

    2013-01-01

    The present study aimed to evaluate the effect of using one-stage posterior C2 and C3 pedicle screw fixation or combined anterior C2-C3 fusion in the treatment of unstable hangman’s fracture. A total of 13 patients with unstable hangman’s fractures underwent C2 and C3 pedicle screw fixation, lamina interbody fusion or combined anterior C2-C3 fusion and imaging examinations to evaluate the fracture fixation and healing condition at three days and three months following surgery. Postoperative X-ray and computed tomography (CT) results showed high fracture reduction, good internal fixation position and reliable fracture fixation. The three-month postoperative CT showed good vertebral fracture healing. C2 and C3 pedicle screw fixation has a good curative effect in the treatment of unstable hangman’s fracture. The direct fixation of the fracture enables early ambulation by the patients. PMID:23408668

  17. Posterior Fixation Techniques in the Subaxial Cervical Spine

    PubMed Central

    Ghori, Ahmer; Makanji, Heeren; Cha, Thomas

    2015-01-01

    This article reviews the historical context, indications, techniques, and complications of four posterior fixation techniques to stabilize the subaxial cervical spine. Specifically, posterior wiring, laminar screw fixation, lateral mass fixation, and pedicle screw fixation are among the common methods of operative fixation of the subaxial cervical spine. While wiring and laminar screw fixation are now rarely used, both lateral mass and pedicle screw fixation are technically challenging and present the risk of significant complications if performed incorrectly. With a sound understanding of anatomy and rigorous preoperative evaluation of bony structures, both lateral mass and pedicle screw fixation provide a safe and reliable method for subaxial cervical spine fixation. PMID:26594602

  18. [Visual fixation features after treatment of exudative age macular degeneration].

    PubMed

    Surguch, V K; Surnina, Z V; Sizova, M V

    2011-01-01

    Changes of visual fixation in patients with choroidal neovascularitation (CNV) associated with age macular degeneration (AMD) after bevacizumab are studied. 45 patients (45 eyes) with active CNV treated with intravitreal bevacizumab were enrolled into the study. Visual fixation was studied before and 3-6 months after treatment using original method that included fundus foto and fluorescein angiography. Fixation relative to fovea and lesion was evaluated. Foveal fixation beyond lesion was found in 9%, foveal fixation within lesion--in 47%, extrafoveal fixation beyond lesion--in 18%, extrafoveal fixation within lesion--in 26% of patients. Changes of fixation localization after treatment was found in 24% patients. Examination of visual fixation may be useful for prognosis of anti-VEGF treatment efficacy in patients with CNV. PMID:21721271

  19. Pars plana vitrectomy combined with internal limiting membrane peeling for recurrent macular edema due to branch retinal vein occlusion after antivascular endothelial growth factor treatments

    PubMed Central

    Shirakata, Yukari; Fukuda, Kouki; Fujita, Tomoyoshi; Nakano, Yuki; Nomoto, Hiroyuki; Yamaji, Hidetaka; Shiraga, Fumio; Tsujikawa, Akitaka

    2016-01-01

    Purpose To evaluate the anatomic and functional outcomes of pars plana vitrectomy combined with internal limiting membrane peeling for recurrent macular edema (ME) due to branch retinal vein occlusion (BRVO) after intravitreal injections of antivascular endothelial growth factor (anti-VEGF) agents. Methods Twenty-four eyes of 24 patients with treatment-naive ME from BRVO were treated with intravitreal injections of anti-VEGF agents. Recurred ME was treated with pars plana vitrectomy combined with internal limiting membrane peeling. Results After the surgery, ME was significantly reduced at 1 month (P=0.031) and the reduction increased with time (P=0.007 at the final visit). With the reduction in ME, treated eyes showed a slow improvement in visual acuity (VA). At the final visit, improvement in VA was statistically significant compared with baseline (P=0.048). The initial presence of cystoid spaces, serous retinal detachment, or subretinal hemorrhage under the fovea, as well as retinal perfusion status, showed no association with VA improvement. However, the presence of epiretinal membrane showed a significant association with the visual recovery. Although eyes without epiretinal membrane showed visual improvement (−0.10±0.32 in logarithm of the minimum angle of resolution [logMAR]), eyes with epiretinal membrane showed greater visual improvement (−0.38±0.12 in logMAR, P=0.012). Conclusion For recurrent ME due to BRVO after anti-VEGF treatment, particularly when accompanied by epiretinal membrane, pars plana vitrectomy combined with internal limiting membrane peeling might be a possible treatment option. PMID:26917950

  20. Limited and time-delayed internal resource allocation generates oscillations and chaos in the dynamics of citrus crops

    NASA Astrophysics Data System (ADS)

    Ye, Xujun; Sakai, Kenshi

    2013-12-01

    Alternate bearing or masting is a yield variability phenomenon in perennial crops. The complex dynamics in this phenomenon have stimulated much ecological research. Motivated by data from an eight-year experiment with forty-eight individual trees, we explored the mechanism inherent to these dynamics in Satsuma mandarin (Citrus unshiu Marc.). By integrating high-resolution imaging technology, we found that the canopy structure and reproduction output of individual citrus crops are mutually dependent on each other. Furthermore, it was revealed that the mature leaves in early season contribute their energy to the fruiting of the current growing season, whereas the younger leaves show a delayed contribution to the next growing season. We thus hypothesized that the annual yield variability might be caused by the limited and time-delayed resource allocation in individual plants. A novel lattice model based on this hypothesis demonstrates that this pattern of resource allocation will generate oscillations and chaos in citrus yield.

  1. Limited and time-delayed internal resource allocation generates oscillations and chaos in the dynamics of citrus crops

    SciTech Connect

    Ye, Xujun; Sakai, Kenshi

    2013-12-15

    Alternate bearing or masting is a yield variability phenomenon in perennial crops. The complex dynamics in this phenomenon have stimulated much ecological research. Motivated by data from an eight-year experiment with forty-eight individual trees, we explored the mechanism inherent to these dynamics in Satsuma mandarin (Citrus unshiu Marc.). By integrating high-resolution imaging technology, we found that the canopy structure and reproduction output of individual citrus crops are mutually dependent on each other. Furthermore, it was revealed that the mature leaves in early season contribute their energy to the fruiting of the current growing season, whereas the younger leaves show a delayed contribution to the next growing season. We thus hypothesized that the annual yield variability might be caused by the limited and time-delayed resource allocation in individual plants. A novel lattice model based on this hypothesis demonstrates that this pattern of resource allocation will generate oscillations and chaos in citrus yield.

  2. International neurocognitive normative study: neurocognitive comparison data in diverse resource-limited settings: AIDS Clinical Trials Group A5271.

    PubMed

    Robertson, K; Jiang, H; Evans, S R; Marra, C M; Berzins, B; Hakim, J; Sacktor, N; Silva, M Tulius; Campbell, T B; Nair, A; Schouten, J; Kumwenda, J; Supparatpinyo, K; Tripathy, S; Kumarasamy, N; la Rosa, A; Montano, S; Mwafongo, A; Firnhaber, C; Sanne, I; Naini, L; Amod, F; Walawander, A

    2016-08-01

    Infrastructure for conducting neurological research in resource-limited settings (RLS) is limited. The lack of neurological and neuropsychological (NP) assessment and normative data needed for clinical interpretation impedes research and clinical care. Here, we report on ACTG 5271, which provided neurological training of clinical site personnel and collected neurocognitive normative comparison data in diverse settings. At ten sites in seven RLS countries, we provided training for NP assessments. We collected normative comparison data on HIV- participants from Brazil (n = 240), India (n = 480), Malawi (n = 481), Peru (n = 239), South Africa (480), Thailand (n = 240), and Zimbabwe (n = 240). Participants had a negative HIV test within 30 days before standardized NP exams were administered at baseline and 770 at 6 months. Participants were enrolled in eight strata, gender (female and male), education (<10 and ≥10 years), and age (<35 and ≥35 years). Of 2400 enrolled, 770 completed the 6-month follow-up. As expected, significant between-country differences were evident in all the neurocognitive test scores (p < 0.0001). There was variation between the age, gender, and education strata on the neurocognitive tests. Age and education were important variables for all tests; older participants had poorer performance, and those with higher education had better performance. Women had better performance on verbal learning/memory and speed of processing tests, while men performed better on motor tests. This study provides the necessary neurocognitive normative data needed to build infrastructure for future neurological and neurocognitive studies in diverse RLS. These normative data are a much-needed resource for both clinicians and researchers. PMID:26733457

  3. Revision surgery for nonunion after early failure of fixation of fractures of the distal humerus.

    PubMed

    Ali, A; Douglas, H; Stanley, D

    2005-08-01

    Sixteen patients who underwent a revision operation for nonunion of fractures of the distal humerus following previous internal fixation were reviewed at a mean follow-up of 39 months (8 to 69). The Mayo elbow performance score was excellent in 11, good in two, fair in two and poor in one. In 15 patients union was achieved and in one with an infected nonunion a subsequent bone graft was necessary in order to obtain union.Age, gender, a history of smoking, mechanism of the injury and the AO classification of the initial fracture did not correlate with the development of nonunion. In 12 patients (75%), the initial fixation was assessed as being suboptimal. The primary surgery was regarded as adequate in only three patients. Our findings suggest that the most important determinant of nonunion of a distal humeral fracture after surgery is the adequacy of fixation. PMID:16049248

  4. S1PR4 Signaling Attenuates ILT 7 Internalization To Limit IFN-α Production by Human Plasmacytoid Dendritic Cells.

    PubMed

    Dillmann, Christina; Ringel, Christian; Ringleb, Julia; Mora, Javier; Olesch, Catherine; Fink, Annika F; Roberts, Edward; Brüne, Bernhard; Weigert, Andreas

    2016-02-15

    Plasmacytoid dendritic cells (pDCs) produce large amounts of type I IFN in response to TLR7/9 ligands. This conveys antiviral effects, activates other immune cells (NK cells, conventional DCs, B, and T cells), and causes the induction and expansion of a strong inflammatory response. pDCs are key players in various type I IFN-driven autoimmune diseases such as systemic lupus erythematosus or psoriasis, but pDCs are also involved in (anti-)tumor immunity. The sphingolipid sphingosine-1-phosphate (S1P) signals through five G-protein-coupled receptors (S1PR1-5) to regulate, among other activities, immune cell migration and activation. The present study shows that S1P stimulation of human, primary pDCs substantially decreases IFN-α production after TLR7/9 activation with different types of CpG oligodeoxynucleotides or tick-borne encephalitis vaccine, which occurred in an S1PR4-dependent manner. Mechanistically, S1PR4 activation preserves the surface expression of the human pDC-specific inhibitory receptor Ig-like transcript 7. We provide novel information that Ig-like transcript 7 is rapidly internalized upon receptor-mediated endocytosis of TLR7/9 ligands to allow high IFN-α production. This is antagonized by S1PR4 signaling, thus decreasing TLR-induced IFN-α secretion. At a functional level, attenuated IFN-α production failed to alter Ag-driven T cell proliferation in pDC-dependent T cell activation assays, but shifted cytokine production of T cells from a Th1 (IFN-γ) to a regulatory (IL-10) profile. In conclusion, S1PR4 agonists block human pDC activation and may therefore be a promising tool to restrict pathogenic IFN-α production. PMID:26783340

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

    PubMed

    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. PMID:27070124

  6. The use of external fixators in the immobilization of pediatric fractures.

    PubMed

    Norman, D; Peskin, B; Ehrenraich, A; Rosenberg, N; Bar-Joseph, G; Bialik, V

    2002-09-01

    The use of external fixation in the immobilization of diaphyseal and metaphyseal fractures in children is still controversial, as these fractures are generally managed by immediate plaster casting, by traction followed by casting, by various methods of internal fixation, including the recently developed flexible rods, and by plating. Between 1982 and 1998, we treated 64 children with fractures of the long bones of the lower limb using external fixation, 44 of whom were available for follow-up (46 fractures). Their average age on the day of injury was 8.l years. Average follow-up extended for 4 years. The external fixation used was left in place for an average of 67 days. Full range of movement was achieved in 42 children (44 limbs). The longitudinal axis was anatomically correct (<5 degrees angulation) in 40 children (42 limbs). Due to malalignment of the fracture (15 degrees varus) in one child, tibial osteotomy was performed 4 years after fracture healing. There was no leg length discrepancy in 38 children, and shortening of >2 cm was measured in the fractured limbs of 2 children. We found the use of external fixators to be easy, quick, with a short learning curve, and appropriate for comminuted and closed fractures of the long bones, and especially for children with polytrauma. PMID:12228797

  7. What are the minimum requirements for ketogenic diet services in resource-limited regions? Recommendations from the International League Against Epilepsy Task Force for Dietary Therapy.

    PubMed

    Kossoff, Eric H; Al-Macki, Nabil; Cervenka, Mackenzie C; Kim, Heung D; Liao, Jianxiang; Megaw, Katherine; Nathan, Janak K; Raimann, Ximena; Rivera, Rocio; Wiemer-Kruel, Adelheid; Williams, Emma; Zupec-Kania, Beth A

    2015-09-01

    Despite the increasing use of dietary therapies for children and adults with refractory epilepsy, the availability of these treatments in developing countries with limited resources remains suboptimal. One possible contributory factor may be the costs. There is often reported a significant perceived need for a large ketogenic diet team, supplements, laboratory studies, and follow-up visits to provide this treatment. The 2009 Epilepsia Consensus Statement described ideal requirements for a ketogenic diet center, but in some situations this is not feasible. As a result, the International League Against Epilepsy (ILAE) Task Force on Dietary Therapy was asked to convene and provide practical, cost-effective recommendations for new ketogenic diet centers in resource-limited regions of the world. PMID:26033161

  8. Chemical and physical basics of routine formaldehyde fixation

    PubMed Central

    Thavarajah, Rooban; Mudimbaimannar, Vidya Kazhiyur; Elizabeth, Joshua; Rao, Umadevi Krishnamohan; Ranganathan, Kannan

    2012-01-01

    Formaldehyde is the widely employed fixative that has been studied for decades. The chemistry of fixation has been studied widely since the early 20th century. However, very few studies have been focused on the actual physics/chemistry aspect of process of this fixation. This article attempts to explain the chemistry of formaldehyde fixation and also to study the physical aspects involved in the fixation. The factors involved in the fixation process are discussed using well documented mathematical and physical formulae. The deeper understanding of these factors will enable pathologist to optimize the factors and use them in their favor. PMID:23248474

  9. Chemical and physical basics of routine formaldehyde fixation.

    PubMed

    Thavarajah, Rooban; Mudimbaimannar, Vidya Kazhiyur; Elizabeth, Joshua; Rao, Umadevi Krishnamohan; Ranganathan, Kannan

    2012-09-01

    Formaldehyde is the widely employed fixative that has been studied for decades. The chemistry of fixation has been studied widely since the early 20(th) century. However, very few studies have been focused on the actual physics/chemistry aspect of process of this fixation. This article attempts to explain the chemistry of formaldehyde fixation and also to study the physical aspects involved in the fixation. The factors involved in the fixation process are discussed using well documented mathematical and physical formulae. The deeper understanding of these factors will enable pathologist to optimize the factors and use them in their favor. PMID:23248474

  10. Biometric recognition via fixation density maps

    NASA Astrophysics Data System (ADS)

    Rigas, Ioannis; Komogortsev, Oleg V.

    2014-05-01

    This work introduces and evaluates a novel eye movement-driven biometric approach that employs eye fixation density maps for person identification. The proposed feature offers a dynamic representation of the biometric identity, storing rich information regarding the behavioral and physical eye movement characteristics of the individuals. The innate ability of fixation density maps to capture the spatial layout of the eye movements in conjunction with their probabilistic nature makes them a particularly suitable option as an eye movement biometrical trait in cases when free-viewing stimuli is presented. In order to demonstrate the effectiveness of the proposed approach, the method is evaluated on three different datasets containing a wide gamut of stimuli types, such as static images, video and text segments. The obtained results indicate a minimum EER (Equal Error Rate) of 18.3 %, revealing the perspectives on the utilization of fixation density maps as an enhancing biometrical cue during identification scenarios in dynamic visual environments.

  11. Periprosthetic femoral fracture--a biomechanical comparison between Vancouver type B1 and B2 fixation methods.

    PubMed

    Moazen, Mehran; Mak, Jonathan H; Etchels, Lee W; Jin, Zhongmin; Wilcox, Ruth K; Jones, Alison C; Tsiridis, Eleftherios

    2014-03-01

    Current clinical data suggest a higher failure rate for internal fixation in Vancouver type B1 periprosthetic femoral fracture (PFF) fixations compared to long stem revision in B2 fractures. The aim of this study was to compare the biomechanical performance of several fixations in the aforementioned fractures. Finite element models of B1 and B2 fixations, previously corroborated against in vitro experimental models, were compared. The results indicated that in treatment of B1 fractures, a single locking plate can be without complications provided partial weight bearing is followed. In case of B2 fractures, long stem revision and bypassing the fracture gap by two femoral diameters are recommended. Considering the risk of single plate failure, long stem revision could be considered in all comminuted B1 and B2 fractures. PMID:24035619

  12. Image-guided percutaneous internal fixation of sacral fracture.

    PubMed

    Kinon, Merritt D; Desai, Rupen; Loriaux, Daniel; Houten, John K

    2016-01-01

    Percutaneous iliosacral screw placement is a technically challenging procedure with a significant complication profile for misplaced screws. The use of stereotactic image guidance has been shown to provide superior accuracy in the placement of spinal instrumentation. Here, the authors describe a novel application of O-arm technology (Medtronic Sofamor Danek, Memphis, TN, USA) to help safely place iliosacral screws for the treatment of a traumatic sacral fracture. PMID:26433323

  13. Evaluating Detection Limits of Next-Generation Sequencing for the Surveillance and Monitoring of International Marine Pests

    PubMed Central

    Pochon, Xavier; Bott, Nathan J.; Smith, Kirsty F.; Wood, Susanna A.

    2013-01-01

    Most surveillance programmes for marine invasive species (MIS) require considerable taxonomic expertise, are laborious, and are unable to identify species at larval or juvenile stages. Therefore, marine pests may go undetected at the initial stages of incursions when population densities are low. In this study, we evaluated the ability of the benchtop GS Junior™ 454 pyrosequencing system to detect the presence of MIS in complex sample matrices. An initial in-silico evaluation of the mitochondrial cytochrome c oxidase subunit I (COI) and the nuclear small subunit ribosomal DNA (SSU) genes, found that multiple primer sets (targeting a ca. 400 base pair region) would be required to obtain species level identification within the COI gene. In contrast a single universal primer set was designed to target the V1–V3 region of SSU, allowing simultaneous PCR amplification of a wide taxonomic range of MIS. To evaluate the limits of detection of this method, artificial contrived communities (10 species from 5 taxonomic groups) were created using varying concentrations of known DNA samples and PCR products. Environmental samples (water and sediment) spiked with one or five 160 hr old Asterias amurensis larvae were also examined. Pyrosequencing was able to recover DNA/PCR products of individual species present at greater than 0.64% abundance from all tested contrived communities. Additionally, single A. amurensis larvae were detected from both water and sediment samples despite the co-occurrence of a large array of environmental eukaryotes, indicating an equivalent sensitivity to quantitative PCR. NGS technology has tremendous potential for the early detection of marine invasive species worldwide. PMID:24023913

  14. Evaluating detection limits of next-generation sequencing for the surveillance and monitoring of international marine pests.

    PubMed

    Pochon, Xavier; Bott, Nathan J; Smith, Kirsty F; Wood, Susanna A

    2013-01-01

    Most surveillance programmes for marine invasive species (MIS) require considerable taxonomic expertise, are laborious, and are unable to identify species at larval or juvenile stages. Therefore, marine pests may go undetected at the initial stages of incursions when population densities are low. In this study, we evaluated the ability of the benchtop GS Junior™ 454 pyrosequencing system to detect the presence of MIS in complex sample matrices. An initial in-silico evaluation of the mitochondrial cytochrome c oxidase subunit I (COI) and the nuclear small subunit ribosomal DNA (SSU) genes, found that multiple primer sets (targeting a ca. 400 base pair region) would be required to obtain species level identification within the COI gene. In contrast a single universal primer set was designed to target the V1-V3 region of SSU, allowing simultaneous PCR amplification of a wide taxonomic range of MIS. To evaluate the limits of detection of this method, artificial contrived communities (10 species from 5 taxonomic groups) were created using varying concentrations of known DNA samples and PCR products. Environmental samples (water and sediment) spiked with one or five 160 hr old Asterias amurensis larvae were also examined. Pyrosequencing was able to recover DNA/PCR products of individual species present at greater than 0.64% abundance from all tested contrived communities. Additionally, single A. amurensis larvae were detected from both water and sediment samples despite the co-occurrence of a large array of environmental eukaryotes, indicating an equivalent sensitivity to quantitative PCR. NGS technology has tremendous potential for the early detection of marine invasive species worldwide. PMID:24023913

  15. Preauricular transmasseteric anteroparotid approach for extracorporeal fixation of mandibular condyle fractures

    PubMed Central

    Gali, Rajasekhar; Devireddy, Sathya Kumar; Venkata, Kishore Kumar Rayadurgam; Kanubaddy, Sridhar Reddy; Nemaly, Chaithanyaa; Dasari, Mallikarjuna

    2016-01-01

    Introduction: Free grafting or extracorporeal fixation of traumatically displaced mandibular condyles is sometimes required in patients with severe anteromedial displacement of condylar head. Majority of the published studies report the use of a submandibular, retromandibular or preauricular incisions for the access which have demerits of limited visibility, access and potential to cause damage to facial nerve and other parotid gland related complications. Purpose: This retrospective clinical case record study was done to evaluate the preauricular transmasseteric anteroparotid (P-TMAP) approach for open reduction and extracorporeal fixation of displaced and dislocated high condylar fractures of the mandible. Patients and Methods: This retrospective study involved search of clinical case records of seven patients with displaced and dislocated high condylar fractures treated by open reduction and extracorporeal fixation over a 3-year period. The parameters assessed were as follows: a) the ease of access for retrieval, reimplantation and fixation of the proximal segment; b) the postoperative approach related complications; c) the adequacy of anatomical reduction and stability of fixation; d) the occlusal changes; and the e) TMJ function and radiological changes. Results: Accessibility and visibility were good. Accurate anatomical reduction and fixation were achieved in all the patients. The recorded complications were minimal and transient. Facial nerve (buccal branch) palsy was noted in one patient with spontaneous resolution within 3 months. No cases of sialocele or Frey's syndrome were seen. Conclusion: The P-TMAP approach provides good access for open reduction and extracorporeal fixation of severely displaced condylar fractures. It facilitates retrieval, transplantation, repositioning, fixing the condyle and also reduces the chances of requirement of a vertical ramus osteotomy. It gives straight-line access to condylar head and ramus thereby permitting

  16. Assessment of external fixator reusability using load- and cycle-dependent tests.

    PubMed

    Matsuura, Maiko; Lounici, Smain; Inoue, Nozomu; Walulik, Stephen; Chao, Edmund Y S

    2003-01-01

    No standard method has been established for investigating repeated use of an external fixator. The purpose of the current study was to establish a fatigue testing method for assessing fixator frame reuse. A unilateral DynaFix trade mark external fixator system was tested using high-load and low-cycle (900-150 N at 5 Hz) and low-load and high-cycle (450-100 N at 10 Hz) tests (assumed one use of 500,000 and 1 million cycles, respectively). These loading conditions were selected to simulate single clinical use and to satisfy Food and Drug Administration requirements. In the high-load low-cycle test, substantial failure of the serrated joint occurred before completion of the first simulated use. In the low-load high-cycle test, all fixators completed three simulated clinical uses without failure, although (1/4) of the serrated joint components had hairline cracks. The high-load low-cycle test identified the fixator components which should be examined and replaced if reuse of the fixator is to be considered. Wear and deformation of the set screw on the rotary joint and telescoping mechanisms were observed in the low-load high-cycle test but not in the high-load low-cycle test. Therefore, if the unilateral DynaFix trade mark fixators are being considered for reusability, the number of reuses should be limited as the whole structure of the device will experience fatigue damage as the loading cycle increases. PMID:12579028

  17. Anatomic Locking Plate Fixation for Scaphoid Nonunion

    PubMed Central

    Yeung, Just; Sapienza, Anthony

    2016-01-01

    Nonunion can occur relatively frequently after scaphoid fracture and appears to be associated with severity of injury. There have been a number of techniques described for bone grafting with or without screw fixation to facilitate fracture healing. However, even with operative fixation of scaphoid fractures with bone grafting nonunion or malunion rates of 5 to 10 percent are still reported. This is the first report of an anatomic locking plate for scaphoid fracture repair in a 25-year-old right hand dominant healthy male. PMID:27366338

  18. Evaluation of kidney bean yield and nitrogen fixation under low soil nitrogen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    U.S. Kidney bean cultivars as a group have limited genetic diversity. They also require more intensive crop management than most other bean market classes. The objective of this study was to evaluate biological nitrogen fixation and seed yield in a diverse group of kidney lines. A 250 line Andean be...

  19. Association of nitrogen fixation to water use efficiency and yield traits of peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improvement of N2 fixation might be an effective strategy in peanut breeding for high yield under drought stress conditions. However, under water limited conditions peanut varieties having high water-use efficiency (WUE) are favorable. A pot experiment was conducted under greenhouse conditions at ...

  20. The Impact of Type of Examples on Originality: Explaining Fixation and Stimulation Effects

    ERIC Educational Resources Information Center

    Agogué, Marine; Kazakçi, Akin; Hatchuel, Armand; Le Masson, Pascal; Weil, Benoit; Poirel, Nicolas; Cassotti, Mathieu

    2014-01-01

    There are obstacles to creativity: one of them is called fixation effect, the fact that some knowledge about existing or obvious solutions is spontaneously activated and constrains the generation of new solutions. Converging evidence in cognitive psychology has indicated that the ability to generate original ideas can be limited by recently…

  1. Applying Cross-Pin System in Both Femoral and Tibial Fixation in Anterior Cruciate Ligament Reconstruction Using Hamstring Tendons

    PubMed Central

    Qi, Wei; Liu, Yujie; Xue, Jing; Li, Haifeng; Wang, Junliang; Qu, Feng

    2015-01-01

    Use of the RigidFix Cross Pin System (DePuy Mitek, Raynham, MA) is a popular technique for femoral fixation of grafts in anterior cruciate ligament reconstruction (ACLR). However, tibial fixation is still limited to the use of interference screws and post fixation, and few surgeons apply the femoral RigidFix system in tibial fixation. Meanwhile, tunnel enlargement is still a problem that affects the outcome of ACLR with hamstring grafts. We have used the femoral RigidFix system in femoral and tibial fixation. The rod top of the guide frame should be placed under the level of the subchondral bone at the proximal end of the tibial tunnel to ensure that the pins will not be inserted into the joint. The pins are inserted through the center of the lateral tibia. Using our technique, the fixation points of the femur and tibia are close to the anterior cruciate ligament insertions, and full contact of the graft with the tunnel wall can be accomplished. On the basis of our preliminary observations and investigation, we are optimistic about the prospect of performing ACLR using the RigidFix system in femoral and tibial fixation. PMID:26697293

  2. Inner ear tissue preservation by rapid freezing: improving fixation by high-pressure freezing and hybrid methods.

    PubMed

    Bullen, A; Taylor, R R; Kachar, B; Moores, C; Fleck, R A; Forge, A

    2014-09-01

    In the preservation of tissues in as 'close to life' state as possible, rapid freeze fixation has many benefits over conventional chemical fixation. One technique by which rapid freeze-fixation can be achieved, high pressure freezing (HPF), has been shown to enable ice crystal artefact-free freezing and tissue preservation to greater depths (more than 40 μm) than other quick-freezing methods. Despite increasingly becoming routine in electron microscopy, the use of HPF for the fixation of inner ear tissue has been limited. Assessment of the quality of preservation showed routine HPF techniques were suitable for preparation of inner ear tissues in a variety of species. Good preservation throughout the depth of sensory epithelia was achievable. Comparison to chemically fixed tissue indicated that fresh frozen preparations exhibited overall superior structural preservation of cells. However, HPF fixation caused characteristic artefacts in stereocilia that suggested poor quality freezing of the actin bundles. The hybrid technique of pre-fixation and high pressure freezing was shown to produce cellular preservation throughout the tissue, similar to that seen in HPF alone. Pre-fixation HPF produced consistent high quality preservation of stereociliary actin bundles. Optimising the preparation of samples with minimal artefact formation allows analysis of the links between ultrastructure and function in inner ear tissues. PMID:25016142

  3. Inner ear tissue preservation by rapid freezing: Improving fixation by high-pressure freezing and hybrid methods

    PubMed Central

    Bullen, A.; Taylor, R.R.; Kachar, B.; Moores, C.; Fleck, R.A.; Forge, A.

    2014-01-01

    In the preservation of tissues in as ‘close to life’ state as possible, rapid freeze fixation has many benefits over conventional chemical fixation. One technique by which rapid freeze-fixation can be achieved, high pressure freezing (HPF), has been shown to enable ice crystal artefact-free freezing and tissue preservation to greater depths (more than 40 μm) than other quick-freezing methods. Despite increasingly becoming routine in electron microscopy, the use of HPF for the fixation of inner ear tissue has been limited. Assessment of the quality of preservation showed routine HPF techniques were suitable for preparation of inner ear tissues in a variety of species. Good preservation throughout the depth of sensory epithelia was achievable. Comparison to chemically fixed tissue indicated that fresh frozen preparations exhibited overall superior structural preservation of cells. However, HPF fixation caused characteristic artefacts in stereocilia that suggested poor quality freezing of the actin bundles. The hybrid technique of pre-fixation and high pressure freezing was shown to produce cellular preservation throughout the tissue, similar to that seen in HPF alone. Pre-fixation HPF produced consistent high quality preservation of stereociliary actin bundles. Optimising the preparation of samples with minimal artefact formation allows analysis of the links between ultrastructure and function in inner ear tissues. PMID:25016142

  4. The importance of regulation of nitrogen fixation

    NASA Astrophysics Data System (ADS)

    Menge, D. N.

    2012-12-01

    from systematic forest inventory data can be explained by a concomitant switch from predominantly facultative N-fixing trees to predominantly obligate N-fixing trees. This transition in the dominant N-fixing strategy would have important consequences for the rate at which CO2 fertilization can occur and the extent of N surplus in different biomes. These theoretical and forest inventory results suggest that greater knowledge of BNF strategies would greatly increase our understanding of the distribution of N fixers and ecosystem responses to global change. I will finish the talk with a brief literature synthesis that attempts to draw generalizations about BNF strategies. With the limited data available, actinorhizal symbioses in temperate environments appear to be obligate but rhizobial symbioses appear to employ different strategies in different environments. From these results it is unclear whether the strategy is more strongly influenced by the microbes, the plants, or the environments in which the symbiosis has evolved; answering this question would point toward the best ways to incorporate N fixation into global ecosystem models.

  5. Dinitrogen fixation associated with shoots of aquatic carnivorous plants: is it ecologically important?

    PubMed Central

    Sirová, Dagmara; Šantrůček, Jiří; Adamec, Lubomír; Bárta, Jiří; Borovec, Jakub; Pech, Jiří; Owens, Sarah M.; Šantrůčková, Hana; Schäufele, Rudi; Štorchová, Helena; Vrba, Jaroslav

    2014-01-01

    Background and Aims Rootless carnivorous plants of the genus Utricularia are important components of many standing waters worldwide, as well as suitable model organisms for studying plant–microbe interactions. In this study, an investigation was made of the importance of microbial dinitrogen (N2) fixation in the N acquisition of four aquatic Utricularia species and another aquatic carnivorous plant, Aldrovanda vesiculosa. Methods 16S rRNA amplicon sequencing was used to assess the presence of micro-organisms with known ability to fix N2. Next-generation sequencing provided information on the expression of N2 fixation-associated genes. N2 fixation rates were measured following 15N2-labelling and were used to calculate the plant assimilation rate of microbially fixed N2. Key Results Utricularia traps were confirmed as primary sites of N2 fixation, with up to 16 % of the plant-associated microbial community consisting of bacteria capable of fixing N2. Of these, rhizobia were the most abundant group. Nitrogen fixation rates increased with increasing shoot age, but never exceeded 1·3 μmol N g–1 d. mass d–1. Plant assimilation rates of fixed N2 were detectable and significant, but this fraction formed less than 1 % of daily plant N gain. Although trap fluid provides conditions favourable for microbial N2 fixation, levels of nif gene transcription comprised <0·01 % of the total prokaryotic transcripts. Conclusions It is hypothesized that the reason for limited N2 fixation in aquatic Utricularia, despite the large potential capacity, is the high concentration of NH4-N (2·0–4·3 mg L–1) in the trap fluid. Resulting from fast turnover of organic detritus, it probably inhibits N2 fixation in most of the microorganisms present. Nitrogen fixation is not expected to contribute significantly to N nutrition of aquatic carnivorous plants under their typical growth conditions; however, on an annual basis the plant–microbe system can supply nitrogen in the order of

  6. Cr3+-doped fluorides and oxides: role of internal fields and limitations of the Tanabe-Sugano approach.

    PubMed

    Trueba, A; García-Lastra, J M; Garcia-Fernandez, P; Aramburu, J A; Barriuso, M T; Moreno, M

    2011-11-24

    This work is aimed at clarifying the changes on optical spectra of Cr(3+) impurities due to either a host lattice variation or a hydrostatic pressure, which can hardly be understood by means of the usual Tanabe-Sugano (TS) approach assuming that the Racah parameter, B, grows when covalency decreases. For achieving this goal, the optical properties of Cr(3+)-doped LiBaF(3) and KMgF(3) model systems have been explored by means of high level ab initio calculations on CrF(6)(3-) units subject to the electric field, E(R)(r), created by the rest of the lattice ions. These calculations, which reproduce available experimental data, indicate that the energy, E((2)E), of the (2)E(t(2g)(3)) → (4)A(2)(t(2g)(3)) emission transition is nearly independent of the host lattice. By contrast, the energy difference corresponding to (4)A(2)(t(2g)(3)) → (4)T(1)(t(2g)(2)e(g)(1)) and (4)A(2)(t(2g)(3)) → (4)T(2)(t(2g)(2)e(g)(1)) excitations, Δ((4)T(1); (4)T(2)), is shown to increase on passing from the normal to the inverted perovskite host lattice despite the increase in covalency, a fact which cannot be accounted for through the usual TS model. Similarly, when the Cr(3+)-F(-) distance, R, is reduced both Δ((4)T(1); (4)T(2)) and the covalency are found to increase. By analyzing the limitations of the usual model, we found surprising results that are shown to arise from the deformation of both 3d(Cr) and ligand orbitals in the antibonding e(g) orbital, which has a σ character and is more extended than the π t(2g) orbital. By contrast, because of the higher stiffness of the t(2g) orbital, the dependence of E((2)E) with R basically follows the corresponding variation of covalency in that level. Bearing in mind the similarities of the optical properties displayed by Cr(3+) impurities in oxides and fluorides, the present results can be useful for understanding experimental data on Cr(3+)-based gemstones where the local symmetry is lower than cubic. PMID:21981751

  7. TECHNICAL NOTE: Thermal modelling of shape memory alloy fixator for medical application

    NASA Astrophysics Data System (ADS)

    Song, C.; Campbell, P. A.; Frank, T. G.; Cuschieri, A.

    2002-04-01

    Shape memory alloy has been recently used for tissue fixation in minimal access surgery (MAS). It offers an alternative to conventional thread-based suturing of human tissue, with the advantage that its deployment is faster and requires fewer surgical skills. To minimize the damage to surrounding tissue, thermal analysis of tissue-fixator interactions has been done to optimize the heating method, and to predict the heating effect and affected range. The finite-difference method has been used to solve the one-dimensional transient heat transfer problem, with fixator-tissue conduction boundary condition, and the finite-element method was used to build a three-dimensional model for the design optimization. The predicted temperature responses of tissue are considered within a safety range. Tissue temperature drops quickly after heating, and the affected tissue is limited to a layer 1 mm thick next to the fixator. Further in vivo animal studies on the use of the shape memory alloy fixator are ongoing for future applications of tissue suturing in MAS.

  8. High potential of nitrogen fixation in pristine, ombrotrophic bogs in Southern Patagonia

    NASA Astrophysics Data System (ADS)

    Knorr, Klaus-Holger; Horn, Marcus A.; Bahamonde Aguilar, Nelson A.; Borken, Werner

    2015-04-01

    Nitrogen (N) input in pristine peatlands occurs via natural input of inorganic N through atmospheric deposition or biological dinitrogen (N2) fixation. However, N2 fixation is to date mostly attributed to bacteria and algae associated to Sphagnum and its contribution to plant productivity and peat buildup has been often underestimated in previous studies. Based on net N storage, exceptionally low N deposition, and high abundance of vascular plants at pristine peatlands in Southern Patagonia, we hypothesized that there must be a high potential of non-symbiotic N2 fixation not limited to the occurrence of Sphagnum. To this end, we chose two ombrotrophic bogs with spots that are dominated either by Sphagnum or by vascular, cushion-forming plants and sampled peat from different depths for incubation with 15N2 to determine N2 fixation potentials. Moreover, we analyzed 15N2 fixation by a nodule-forming, endemic conifer inhabiting the peatlands. Results from 15N2 uptake were compared to the conventional approach to study N2 fixation by the acetylene reduction assay (ARA). Using 15N2 as a tracer, high non-symbiotic N2 fixation rates of 0.3-1.4 μmol N g-1 d-1 were found down to 50 cm under micro-oxic conditions (2 vol.%) in samples from both plots either covered by Sphagnum magellanicum or by vascular cushion plants. Peat N concentrations suggested a higher potential of non-symbiotic N2 fixation under cushion plants, likely because of the availability of easily decomposable organic compounds as substrates and oxic conditions in the rhizosphere. In the Sphagnum plots, high N2 fixation below 10 cm depth would rather reflect a potential fixation that may switch on during periods of low water levels when oxygen penetrates deeper into the peat. 15N natural abundance of live Sphagnum from 0-10 cm pointed to N uptake solely from atmospheric deposition and non-symbiotic N2 fixation. 15N signatures of peat from the cushion plant plots indicated additional N supply from N

  9. Biomechanical comparison of four mandibular angle fracture fixation techniques.

    PubMed

    Muñante-Cardenas, Jose Luis; Passeri, Luis Augusto

    2015-06-01

    The aim of this study was to make a comparison of the biomechanical behavior of four different internal fixation systems for mandibular angle fractures. A total of 40 polyurethane mandible replicas were employed with different fixation methods: group 1SP, one 2.0-mm four-hole miniplate; group 2PPL, two 2.0-mm four-hole parallel miniplates; group 3DP, one 3D 2.0-mm four-hole miniplate; and group 3DPP, one 3D 2.0-mm eight-hole miniplate. Each group was subjected to incisal or homolateral molar region loading. The load resistance values were measured at load application causing tip displacement of 1, 3, and 5 mm, and at the time at which the system achieves its maximum strength (MS). Means and standard deviations were compared among groups using analysis of variance and the Tukey test. Group 2PPL showed higher strength for all the displacements. For incisal loading, no statistically significant differences were found between groups 1SP, 3DP, and 3DPP. For molar loading, group 1SP and 3DPP showed statistically significant differences. For MS testing, group 1SP and 2PPL showed statistically significant differences in incisal loading; group 1SP and 3DP showed no statistically significant differences; and group 3DPP showed lower values of strength. Two parallel miniplates provide the most favorable mechanical behavior under the conditions tested. PMID:26000083

  10. Biomechanical Comparison of Four Mandibular Angle Fracture Fixation Techniques

    PubMed Central

    Muñante-Cardenas, Jose Luis; Passeri, Luis Augusto

    2014-01-01

    The aim of this study was to make a comparison of the biomechanical behavior of four different internal fixation systems for mandibular angle fractures. A total of 40 polyurethane mandible replicas were employed with different fixation methods: group 1SP, one 2.0-mm four-hole miniplate; group 2PPL, two 2.0-mm four-hole parallel miniplates; group 3DP, one 3D 2.0-mm four-hole miniplate; and group 3DPP, one 3D 2.0-mm eight-hole miniplate. Each group was subjected to incisal or homolateral molar region loading. The load resistance values were measured at load application causing tip displacement of 1, 3, and 5 mm, and at the time at which the system achieves its maximum strength (MS). Means and standard deviations were compared among groups using analysis of variance and the Tukey test. Group 2PPL showed higher strength for all the displacements. For incisal loading, no statistically significant differences were found between groups 1SP, 3DP, and 3DPP. For molar loading, group 1SP and 3DPP showed statistically significant differences. For MS testing, group 1SP and 2PPL showed statistically significant differences in incisal loading; group 1SP and 3DP showed no statistically significant differences; and group 3DPP showed lower values of strength. Two parallel miniplates provide the most favorable mechanical behavior under the conditions tested. PMID:26000083

  11. Feasibility of purely endoscopic intramedullary fixation of mandibular condyle fractures.

    PubMed

    Frake, Paul C; Goodman, Joseph F; Joshi, Arjun S

    2015-01-01

    The investigators of this study hypothesized that fractures of the mandibular condyle can be repaired using short-segment intramedullary implants and purely endoscopic surgical technique, using a basic science, human cadaver model in an academic center. Endoscopic instrumentation was used through a transoral mucosal incision to place intramedullary implants of 2 cm in length into osteotomized mandibular condyles. The surgical maneuvers that required to insert these implants, including condyle positioning, reaming, implant insertion, and seating of the mandibular ramus, are described herein. Primary outcome was considered as successful completion of the procedure. Ten cadaveric mandibular condyles were successfully repaired with rigid intramedullary internal fixation without the use of external incisions. Both insertion of a peg-type implant and screwing a threaded implant into the condylar head were possible. The inferior portion of the implant remained exposed, and the ramus of the mandible was manipulated into position on the implant using retraction at the sigmoid notch. The results of this study suggest that purely endoscopic repair of fractures of the mandibular condyle is possible by using short-segment intramedullary titanium implants and a transoral endoscopic approach without the need for facial incisions or punctures. The biomechanical advantages of these intramedullary implants, including improved strength and resistance to mechanical failure compared with miniplates, have been recently established. The combination of improved implant design and purely endoscopic technique may allow for improved fixation and reduced surgical- and implant-related morbidity in the treatment of condylar fractures. PMID:25534058

  12. Biomechanical comparison of three fixation techniques used for four-corner arthrodesis.

    PubMed

    Kraisarin, J; Dennison, D G; Berglund, L J; An, K N; Shin, A Y

    2011-09-01

    Clinical results following four-corner arthrodesis vary and suggest that nonunion may be related to certain fixation techniques. The purpose of our study was to examine the displacement between the lunate and capitate following a simulated four-corner arthrodesis with the hypothesis that three types of fixation (Kirschner wires, dorsal circular plate, and a locked dorsal circular plate) would allow different amounts of displacement during simulated wrist flexion and extension. Cadaver wrists with simulated four-corner arthrodeses were loaded cyclically either to implant failure or until the lunocapitate displacement exceeded 1 mm. The locked dorsal circular plate group was significantly more stable than the dorsal circular plate and K-wire groups (p = 0.018 and p = 0.006). While these locked dorsal circular plates appear to be very stable our results are limited only to the biomechanical behavior of these fixation techniques within a cadaver model. PMID:21636620

  13. Carbon and energy fixation of great duckweed Spirodela polyrhiza growing in swine wastewater.

    PubMed

    Wang, Wenguo; Yang, Chuang; Tang, Xiaoyu; Zhu, Qili; Pan, Ke; Cai, Denggao; Hu, Qichun; Ma, Danwei

    2015-10-01

    The ability to fix carbon and energy in swine wastewater of duckweeds was investigated using Spirodela polyrhiza as the model species. Cultures of S. polyrhiza were grown in dilutions of both original swine wastewater (OSW) and anaerobic digestion effluent (ADE) based on total ammonia nitrogen (TAN). Results showed that elevated concentrations of TAN caused decreased growth, carbon fixation, and energy production rates, particularly just after the first rise in two types of swine wastewater. Also, OSW was more suitable for S. polyrhiza cultivation than ADE. Maximum carbon and energy fixation were achieved at OSW-TAN concentrations of 12.08 and 13.07 mg L(-1), respectively. Photosynthetic activity of S. polyrhiza could be inhibited by both nutrient stress (in high-concentration wastewater) and nutrient limitation (in low-concentration wastewater), affecting its growth and ability for carbon-energy fixation. PMID:26036587

  14. Inactivation, sequence, and lacZ fusion analysis of a regulatory locus required for repression of nitrogen fixation genes in Rhodobacter capsulatus.

    PubMed Central

    Kranz, R G; Pace, V M; Caldicott, I M

    1990-01-01

    Transcription of the genes that code for proteins involved in nitrogen fixation in free-living diazotrophs is typically repressed by high internal oxygen concentrations or exogenous fixed nitrogen. The DNA sequence of a regulatory locus required for repression of Rhodobacter capsulatus nitrogen fixation genes was determined. It was shown that this locus, defined by Tn5 insertions and by ethyl methanesulfonate-derived mutations, is homologous to the glnB gene of other organisms. The R. capsulatus glnB gene was upstream of glnA, the gene for glutamine synthetase, in a glnBA operon. beta-Galactosidase expression from an R. capsulatus glnBA-lacZ translational fusion was increased twofold in cells induced by nitrogen limitation relative to that in cells under nitrogen-sufficient conditions. R. capsulatus nifR1, a gene that was previously shown to be homologous to ntrC and that is required for transcription of nitrogen fixation genes, was responsible for approximately 50% of the transcriptional activation of this glnBA fusion in cells induced under nitrogen-limiting conditions. R. capsulatus GLNB, NIFR1, and NIFR2 (a protein homologous to NTRB) were proposed to transduce the nitrogen status in the cell into repression or activation of other R. capsulatus nif genes. Repression of nif genes in response to oxygen was still present in R. capsulatus glnB mutants and must have occurred at a different level of control in the regulatory circuit. Images FIG. 4 FIG. 5 PMID:2152916

  15. Diazotrophy in the Deep: Measuring Rates and Identifying Biological Mediators of N2 fixation in Deep-Sea Sediments

    NASA Astrophysics Data System (ADS)

    Dekas, A. E.; Fike, D. A.; Chadwick, G.; Connon, S. A.; Orphan, V. J.

    2013-12-01

    Biological N2 fixation (the conversion of N2 to NH3) is the largest natural source of bioavailable nitrogen to the biosphere, and dictates the rate of community productivity in many nitrogen-limited environments. Deep-sea sediments are traditionally not thought to host N2 fixation, however evidence from a metagenomics dataset targeting deep-sea methanotrophic archaea (ANME) suggested their ability to fix N2 (Pernthaler, et al., PNAS 2008). Using stable isotope labeling experiments and FISH-NanoSIMS, a technique which allows the visualization of isotopic composition within phylogenetically identified cells on the nanometer scale, we demonstrated that the ANME are capable of N2 fixation (Dekas et al., Science 2009). In the present work, we use FISH-NanoSIMS and bulk Isotope Ratio Mass Spectrometry (IRMS) to show that the ANME are the most significant source of new nitrogen at a Costa Rican methane seep. This suggests that the ANME may play a significant role in N2 fixation in methane seeps worldwide. We expand our investigation of deep-sea diazotrophy to include diverse habitats, including sulfide- and carbon-rich whalefalls, and observe that N2 fixation is widespread in sediments on the seafloor. Outside of methane seeps, N2 fixation appears to be mediated by a diversity of anaerobic microbes potentially including methanogens and sulfate reducing bacteria. Interestingly, deep-sea N2 fixation often occurs in the presence of high levels of NH4+. Our observations challenge long-held hypotheses about where and when N2 fixation occurs, and suggest a bigger role for N2 fixation on the seafloor - and potentially the deep-biosphere - than previously realized.

  16. WHITE LUPIN NITROGEN FIXATION UNDER PHOSPHORUS DEFICIENCY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    White lupin is highly adapted to growth in a low P environment. The objective of the present study was to evaluate whether white lupin grown under P-stress has adaptations in nodulation and N2 fixation that facilitate continued functioning. Nodulated plants were grown in silica sand supplied with N-...

  17. Trichodesmium and nitrogen fixation in the Kuroshio

    NASA Astrophysics Data System (ADS)

    Shiozaki, T.; Takeda, S.; Itoh, S.; Kodama, T.; Liu, X.; Hashihama, F.; Furuya, K.

    2015-07-01

    Nitrogen fixation in the Kuroshio influences nitrogen balance in the North Pacific Ocean. The genus Trichodesmium is recognized as a major diazotroph in the Kuroshio. Although its abundance is higher in the Kuroshio than in adjacent waters, the reason for this difference remains unclear. The present study investigated the abundance of Trichodesmium spp. and nitrogen fixation together with concentrations of dissolved iron and phosphate, whose availabilities potentially control diazotrophy, in the Kuroshio and its marginal seas. We performed the observations near the Miyako Islands, which form part of the Ryukyu Islands, situated along the Kuroshio, since satellite analysis suggested that material transport could occur from the islands to the Kuroshio. Trichodesmium spp. bloomed (> 20 000 filaments L-1) near the Miyako Islands, and the abundance was high in the Kuroshio and the Kuroshio bifurcation region of the East China Sea, but was low in the Philippine Sea. The abundance of Trichodesmium spp. was significantly correlated with the total nitrogen fixation activity. The surface concentrations of dissolved iron (0.19-0.89 nM) and phosphate (< 3-36 nM) were similar for all of the study areas, indicating that the nutrient distribution could not explain the spatial differences in Trichodesmium spp. abundance and nitrogen fixation. We used a numerical model to simulate the transportation of water around the Ryukyu Islands to the Kuroshio. Our results indicate that Trichodesmium growing around the islands situated along the Kuroshio is potentially important for determining diazotrophy in this region.

  18. Binocular Fixation in the Newborn Baby

    ERIC Educational Resources Information Center

    Slater, Alan M.; Findlay, John M.

    1975-01-01

    Three experiments are reported in which 15 babies were presented with visual stimuli which varied in shape and distance from the eye. Results indicated that the majority of subjects binocularly fixated all three stimuli and it was concluded that the newborn baby has the basic requirements for binocular vision. (Author/GO)

  19. Bone cement improves suture anchor fixation.

    PubMed

    Giori, Nicholas J; Sohn, David H; Mirza, Faisal M; Lindsey, Derek P; Lee, Arthur T

    2006-10-01

    Suture anchor fixation failure can occur if the anchor pulls out of bone. We hypothesized that suture anchor fixation can be augmented with polymethylmethacrylate cement, and that polymethylmethacrylate can be used to improve fixation in a stripped anchor hole. Six matched cadaveric proximal humeri were used. On one side, suture anchors were placed and loaded to failure using a ramped cyclic loading protocol. The stripped anchor holes then were injected with approximately 1 cc polymethylmethacrylate, and anchors were replaced and tested again. In the contralateral humerus, polymethylmethacrylate was injected into anchor holes before anchor placement and testing. In unstripped anchors, polymethylmethacrylate increased the number of cycles to failure by 34% and failure load by 71% compared with anchors not augmented with polymethylmethacrylate. Polymethylmethacrylate haugmentation of stripped anchors increased the cycles to failure by 31% and failure load by 111% compared with unstripped uncemented anchors. No difference was found in cycles to failure or failure load between cemented stripped anchors and cemented unstripped anchors. Polymethylmethacrylate can be used to augment fixation, reducing the risk of anchor pull-out failure, regardless whether the suture anchor hole is stripped or unstripped. PMID:16702922

  20. Introduction to Lumbosacral and Sacropelvic Fixation Strategies.

    PubMed

    Hsieh, Patrick C; Mummaneni, Praveen V

    2016-07-01

    We are pleased to present this Neurosurgical Focus video supplement on lumbosacral and sacropelvic fixation strategies. Despite advancement in surgical techniques and technologies in spine, achieving consistent solid fusion across the lumbosacral junction remains a major challenge. The anatomy of the lumbosacral junction allows for a higher range of motion compared to other areas of the thoracolumbar spine. The L5-S1 interspace is exposed to significant shear forces. As a result, complications such as pseudoarthrosis, screw pull-out, implant fracture, or sacral fractures can occur. Complications are particularly seen in long fusion constructs ending across the lumbosacral junction. To reduce these complications, various lumbosacral and sacropelvic fixation techniques have been developed and utilized. The current supplement is intended to provide instructional videos that illustrate several current techniques for lumbosacral and sacropelvic fixation. The collection includes techniques for anterior L5-S1 interbody fusion, minimally invasive L5-S1 interbody fusions, lumbosacral pedicle screw placement, sacroiliac fusion, and sacro-alar-iliac screw placement. The authors of the videos in the supplement have provided detailed narration and video illustration to describe the nuances of the various open and minimally invasive techniques for lumbosacral and sacral-pelvic fixation. We are pleased to have such a collection of quality video illustration from experts in the field. It's been our privilege to serve as guest editors for this supplement and we believe that you will enjoy the contents of this supplement. PMID:27364425

  1. Postmortem inflation and fixation of human lungs

    PubMed Central

    Wright, B. M.; Slavin, G.; Kreel, L.; Callan, K.; Sandin, Brenda

    1974-01-01

    Wright, B. M., Slavin, G., Kreel, L., Callan, K., and Sandin, Brenda (1974).Thorax, 29, 189-194. Postmortem inflation and fixation of human lungs. A method of fixing lungs by inflating them with heated formalin vapour is described. This method facilitates postmortem correlations between radiographic and histological appearances. Images PMID:4598582

  2. Bacterial N2-fixation in mangrove ecosystems: insights from a diazotroph–mangrove interaction

    PubMed Central

    Alfaro-Espinoza, Gabriela; Ullrich, Matthias S.

    2015-01-01

    Mangrove forests are highly productive ecosystems but represent low nutrient environments. Nitrogen availability is one of the main factors limiting mangrove growth. Diazotrophs have been identified as key organisms that provide nitrogen to these environments. N2-fixation by such organisms was found to be higher in the mangrove roots than in surrounding rhizosphere. Moreover, previous studies showed that mangroves grew better in the presence of N2-fixers indicating a potentially mutualistic relationship. However, the molecular signals and mechanisms that govern these interactions are still poorly understood. Here we present novel insights in the interaction of a diazotroph with a mangrove species to improve our understanding of the molecular and ecophysiological relationship between these two organisms under controlled conditions. Our results showed that Marinobacterium mangrovicola is a versatile organism capable of competing with other organisms to survive for long periods in mangrove soils. N2-fixation by this bacterium was up-regulated in the presence of mangrove roots, indicating a possible beneficial interaction. The increase in N2-fixation was limited to cells of the exponential growth phase suggesting that N2-fixation differs over the bacterial growth cycle. Bacterial transformants harboring a transcriptional nifH::gusA fusion showed that M. mangrovicola successfully colonized mangrove roots and simultaneously conducted N2-fixation. The colonization process was stimulated by the lack of an external carbon source suggesting a possible mutualistic relationship. M. mangrovicola represents an interesting genetically accessible diazotroph, which colonize mangrove roots and exhibit higher N2-fixation in the presence of mangrove roots. Consequently, we propose this microorganism as a tool to study molecular interactions between N2-fixers and mangrove plants and to better understand how changes in the environment could impact these important and relatively unknown

  3. Bacterial N2-fixation in mangrove ecosystems: insights from a diazotroph-mangrove interaction.

    PubMed

    Alfaro-Espinoza, Gabriela; Ullrich, Matthias S

    2015-01-01

    Mangrove forests are highly productive ecosystems but represent low nutrient environments. Nitrogen availability is one of the main factors limiting mangrove growth. Diazotrophs have been identified as key organisms that provide nitrogen to these environments. N2-fixation by such organisms was found to be higher in the mangrove roots than in surrounding rhizosphere. Moreover, previous studies showed that mangroves grew better in the presence of N2-fixers indicating a potentially mutualistic relationship. However, the molecular signals and mechanisms that govern these interactions are still poorly understood. Here we present novel insights in the interaction of a diazotroph with a mangrove species to improve our understanding of the molecular and ecophysiological relationship between these two organisms under controlled conditions. Our results showed that Marinobacterium mangrovicola is a versatile organism capable of competing with other organisms to survive for long periods in mangrove soils. N2-fixation by this bacterium was up-regulated in the presence of mangrove roots, indicating a possible beneficial interaction. The increase in N2-fixation was limited to cells of the exponential growth phase suggesting that N2-fixation differs over the bacterial growth cycle. Bacterial transformants harboring a transcriptional nifH::gusA fusion showed that M. mangrovicola successfully colonized mangrove roots and simultaneously conducted N2-fixation. The colonization process was stimulated by the lack of an external carbon source suggesting a possible mutualistic relationship. M. mangrovicola represents an interesting genetically accessible diazotroph, which colonize mangrove roots and exhibit higher N2-fixation in the presence of mangrove roots. Consequently, we propose this microorganism as a tool to study molecular interactions between N2-fixers and mangrove plants and to better understand how changes in the environment could impact these important and relatively unknown

  4. 21 CFR 888.3020 - Intramedullary fixation rod.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Intramedullary fixation rod. 888.3020 Section 888.3020 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3020 Intramedullary fixation rod. (a) Identification. An intramedullary fixation rod...

  5. 21 CFR 888.3020 - Intramedullary fixation rod.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Intramedullary fixation rod. 888.3020 Section 888.3020 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3020 Intramedullary fixation rod. (a) Identification. An intramedullary fixation rod...

  6. Unfixing Design Fixation: From Cause to Computer Simulation

    ERIC Educational Resources Information Center

    Dong, Andy; Sarkar, Somwrita

    2011-01-01

    This paper argues that design fixation, in part, entails fixation at the level of meta-representation, the representation of the relation between a representation and its reference. In this paper, we present a mathematical model that mimics the idea of how fixation can occur at the meta-representation level. In this model, new abstract concepts…

  7. 21 CFR 868.5770 - Tracheal tube fixation device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5770 Tracheal tube fixation device. (a) Identification. A tracheal tube fixation device is a device used to hold a tracheal tube in... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Tracheal tube fixation device. 868.5770...

  8. 21 CFR 868.5770 - Tracheal tube fixation device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5770 Tracheal tube fixation device. (a) Identification. A tracheal tube fixation device is a device used to hold a tracheal tube in... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tracheal tube fixation device. 868.5770...

  9. 21 CFR 888.3010 - Bone fixation cerclage.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bone fixation cerclage. 888.3010 Section 888.3010...) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3010 Bone fixation cerclage. (a) Identification. A bone fixation cerclage is a device intended to be implanted that is made of alloys, such...

  10. 21 CFR 888.3010 - Bone fixation cerclage.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Bone fixation cerclage. 888.3010 Section 888.3010...) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3010 Bone fixation cerclage. (a) Identification. A bone fixation cerclage is a device intended to be implanted that is made of alloys, such...

  11. 21 CFR 868.5770 - Tracheal tube fixation device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5770 Tracheal tube fixation device. (a) Identification. A tracheal tube fixation device is a device used to hold a tracheal tube in... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Tracheal tube fixation device. 868.5770...

  12. [Three-dimensional Finite Element Analysis of Biomechanical Effect of Rigid Fixation and Elastic Fixation on Lumbar Interbody Fusion].

    PubMed

    Wei, Jiangbo; Song, Yueming; Liu, Limin; Zhou, Chunguan; Yang, Xi

    2015-04-01

    This study was aimed to compare the mechanical characteristics under different physiological load conditions with three-dimensional finite element model of rigid fixation and elastic fixation in the lumbar. We observed the stress distribution characteristics of a sample of healthy male volunteer modeling under vertical, flexion and extension torque situation. The outcomes showed that there existed 4-6 times pressure on the connecting rod of rigid fixation compared with the elastic fixations under different loads, and the stress peak and area of force on elastic fixation were much higher than that of the rigid fixations. The elastic fixation has more biomechanical advantages than rigid fixation in promoting interbody lumbar fusion after surgery. PMID:26211247

  13. Occupational radiation dose to eyes from endoscopic retrograde cholangiopancreatography procedures in light of the revised eye lens dose limit from the International Commission on Radiological Protection

    PubMed Central

    Gallagher, A; Malone, L; O’Reilly, G

    2013-01-01

    Objective: Endoscopic retrograde cholangiopancreatography (ERCP) is a common procedure that combines the use of X-ray fluoroscopy and endoscopy for examination of the bile duct. Published data on ERCP doses are limited, including staff eye dose from ERCP. Occupational eye doses are of particular interest now as the International Commission on Radiological Protection (ICRP) has recommended a reduction in the dose limit to the lens of the eye. The aim of this study was to measure occupational eye doses obtained from ERCP procedures. Methods: A new eye lens dosemeter (EYE-D™, Radcard, Krakow, Poland) was used to measure the ERCP eye dose, Hp(3), at two endoscopy departments in Ireland. A review of radiation protection practice at the two facilities was also carried out. Results: The mean equivalent dose to the lens of the eye of a gastroenterologist is 0.01 mSv per ERCP procedure with an undercouch X-ray tube and 0.09 mSv per ERCP procedure with an overcouch X-ray tube. Staff eye dose normalised to patient kerma area product is also presented. Conclusion: Staff eye doses in ERCP have the potential to exceed the revised ICRP limit of 20 mSv per annum when an overcouch X-ray tube is used. The EYE-D dosemeter was found to be a convenient method for measuring lens dose. Eye doses in areas outside of radiology departments should be kept under review, particularly in light of the new ICRP eye dose limit. Advances in knowledge: Occupational eye lens doses from ERCP procedures have been established using a new commercially available dedicated Hp(3) dosemeter. PMID:23385992

  14. A new perspective on environmental controls of marine nitrogen fixation

    NASA Astrophysics Data System (ADS)

    Landolfi, A.; Koeve, W.; Dietze, H.; Kähler, P.; Oschlies, A.

    2015-06-01

    Growing slowly, marine N2 fixers are generally expected to be competitive only where nitrogen (N) supply is low relative to that of phosphorus (P) with respect to the cellular N:P ratio (R) of nonfixing phytoplankton. This is at odds with observed high N2 fixation rates in the oligotrophic North Atlantic where the ratio of nutrients supplied to the surface is elevated in N relative to the average R (16:1). In this study, we investigate several mechanisms to solve this puzzle: iron limitation, phosphorus enhancement by preferential remineralization or stoichiometric diversity of phytoplankton, and dissolved organic phosphorus (DOP) utilization. Combining resource competition theory and a global coupled ecosystem-circulation model, we find that the additional N and energy investments required for exoenzymatic breakdown of DOP give N2 fixers a competitive advantage in oligotrophic P-starved regions. Accounting for this mechanism expands the ecological niche of N2 fixers also to regions where the nutrient supply is high in N relative to R, yielding, in our model, a pattern consistent with the observed high N2 fixation rates in the oligotrophic North Atlantic.

  15. Femoral neck fracture fixation: rigidity of five techniques compared.

    PubMed Central

    Mackechnie-Jarvis, A C

    1983-01-01

    Artificial cadaveric femoral neck fractures were internally fixed with five different devices and subjected to cyclical loading of 0-1.0 kilonewtons (approximately one body weight) whilst in an anatomical position. Displacement of the proximal fragment was detected by a transducer and charted. Bone strength was assessed by a preliminary control loading phase on the intact bone. Efficiency of each fracture fixator could then be directly compared by the relative movement in each case. Five specimens each were tested with Moore's Pins, Trifin Nail, Garden Screws and a sliding screw-plate (OEC Ltd). By the criteria of the experiment, which put a severe shearing load on the implant, none of these devices reliably bore the representative body weight. An extended barrel-plate, which supported the sliding screw almost up to the fracture line, was then made. This device, employing some of Charnley's concepts, tolerated body weight in four cases out of five. PMID:6887186

  16. Oxygen-Poor Microzones as Potential Sites of Microbial N2 Fixation in Nitrogen-Depleted Aerobic Marine Waters

    PubMed Central

    Paerl, Hans W.; Prufert, Leslie E.

    1987-01-01

    The nitrogen-deficient coastal waters of North Carolina contain suspended bacteria potentially able to fix N2. Bioassays aimed at identifying environmental factors controlling the development and proliferation of N2 fixation showed that dissolved organic carbon (as simple sugars and sugar alcohols) and particulate organic carbon (derived from Spartina alterniflora) additions elicited and enhanced N2 fixation (nitrogenase activity) in these waters. Nitrogenase activity occurred in samples containing flocculent, mucilage-covered bacterial aggregates. Cyanobacterium-bacterium aggregates also revealed N2 fixation. In all cases bacterial N2 fixation occurred in association with surficial microenvironments or microzones. Since nitrogenase is oxygen labile, we hypothesized that the aggregates themselves protected their constituent microbes from O2. Microelectrode O2 profiles revealed that aggregates had lower internal O2 tensions than surrounding waters. Tetrazolium salt (2,3,5-triphenyl-3-tetrazolium chloride) reduction revealed that patchy zones existed both within microbes and extracellularly in the mucilage surrounding microbes where free O2 was excluded. Triphenyltetrazolium chloride reduction also strongly inhibited nitrogenase activity. These findings suggest that N2 fixation is mediated by the availability of the appropriate types of reduced microzones. Organic carbon enrichment appears to serve as an energy and structural source for aggregate formation, both of which were required for eliciting N2 fixation responses of these waters. Images PMID:16347337

  17. Assessment of specimen fixation in a surgical pathology service.

    PubMed Central

    Start, R. D.; Cross, S. S.; Smith, J. H.

    1992-01-01

    The quality of specimen fixation was examined within a routine diagnostic histopathology service. For each specimen the adequacy of fixation was assessed and the transit time between operating theatre and the laboratory was measured. Preliminary fixation was found to be inadequate in 25% of specimens and some form of manipulation to assist fixation was required in 36% of specimens. The mean transit time was 22 (SD 10.7) hours. Specimen fixation and transport are additional factors to consider in quality assurance of histopathology. PMID:1306049

  18. Dark Carbon Fixation: An Important Process in Lake Sediments

    PubMed Central

    Santoro, Ana Lúcia; Bastviken, David; Gudasz, Cristian; Tranvik, Lars; Enrich-Prast, Alex

    2013-01-01

    Close to redox boundaries, dark carbon fixation by chemoautotrophic bacteria may be a large contributor to overall carbon fixation. Still, little is known about the relative importance of this process in lake systems, in spite the potentially high chemoautotrophic potential of lake sediments. We compared rates of dark carbon fixation, bacterial production and oxygen consumption in sediments from four Swedish boreal and seven tropical Brazilian lakes. Rates were highly variable and dark carbon fixation amounted up to 80% of the total heterotrophic bacterial production. The results indicate that non-photosynthetic carbon fixation can represent a substantial contribution to bacterial biomass production, especially in sediments with low organic matter content. PMID:23776549

  19. Comparison of Locked Volar Plating Versus Pinning and External Fixation in the Treatment of Unstable Intraarticular Distal Radius Fractures

    PubMed Central

    Katt, Brian A.; Carothers, Joshua T.

    2007-01-01

    Introduction We retrospectively compared the outcomes of open reduction and internal fixation (ORIF) with volar locking plate versus standard external fixation and percutaneous pinning in treating similar unstable distal radius fractures with a minimum 2-year follow-up. Methods The ORIF group included 41 patients with an average follow-up of 29 months. The external fixation group comprised 14 patients with an average follow-up of 33 months. Average age at presentation was 45 years in the external fixation group and 48 years in the ORIF group. The male/female ratios were 16:25 among the ORIF group and 6:8 in the external fixation group. The two groups were compared for clinical and functional outcomes measured by the disabilities of the arm, shoulder, and hand (DASH) score. Pain scores were similar. Radiographic measurements were also evaluated between groups. Results Final ranges of motion and grip strengths were similar between the two groups. The mean DASH score of the locked volar plate group was 9 compared to 23 for the external fixation group. Radiographically, volar tilt and radial length were significantly better in the patients treated with ORIF. The ORIF group required less therapy visits. No complications occurred in the locked volar plate group whereas two patients had pin tract infections and one had prolonged finger stiffness in the external fixation group. Conclusion Locked volar plating compares favorably to external fixation and pinning for amenable fracture patterns. Whereas grip and range-of-motion data were similar, DASH scores, frequency of rehabilitation, and some radiographic parameters were superior in patients treated with ORIF. PMID:18780086

  20. Assessment of visual fixation in vegetative and minimally conscious states

    PubMed Central

    2014-01-01

    Background Visual fixation plays a key role in the differentiation between vegetative state/unresponsive wakefulness (VS/UWS) syndrome and minimally conscious state (MCS). However, the use of different stimuli changes the frequency of visual fixation occured in patients, thereby possibly affecting the accuracy of the diagnosis. In order to establish a standardized assessment of visual fixation in patients in disorders of consciousness (DOC), we compared the frequency of visual fixation elicited by mirror,a ball and a light. Method Visual fixation was assessed in eighty-one post-comatose patients diagnosed with a MCS or VS/UWS. Occurrence of fixation to different stimuli was analysis used Chi-square testing. Result 40 (49%) out of the 81 patients showed fixation to visual stimuli. Among those, significantly more patients (39, 48%) had visual fixation elicited by mirror compared to a ball (23, 28%) and mirror compared to a light (20, 25%). Conclusion The use of a mirror during the assessment of visual fixation showed higher positive response rate, compared to other stimuli in eliciting a visual fixating response. Therefore, fixation elicited by a mirror can be a very sensitive and accurate test to differentiate the two disorders of consciousness. PMID:25027769

  1. Minimum exposure limits and measured relationships between the vitamin D, erythema and international commission on non-ionizing radiation protection solar ultraviolet.

    PubMed

    Downs, Nathan; Parisi, Alfio; Butler, Harry; Turner, Joanna; Wainwright, Lisa

    2015-01-01

    The International Commission on Non-Ionizing Radiation Protection (ICNIRP) has established guidelines for exposure to ultraviolet radiation in outdoor occupational settings. Spectrally weighted ICNIRP ultraviolet exposures received by the skin or eye in an 8 h period are limited to 30 J m(-2). In this study, the time required to reach the ICNIRP exposure limit was measured daily in 10 min intervals upon a horizontal plane at a subtropical Australian latitude over a full year and compared with the effective Vitamin D dose received to one-quarter of the available skin surface area for all six Fitzpatrick skin types. The comparison of measured solar ultraviolet exposures for the full range of sky conditions in the 2009 measurement period, including a major September continental dust event, show a clear relationship between the weighted ICNIRP and the effective vitamin D dose. Our results show that the horizontal plane ICNIRP ultraviolet exposure may be used under these conditions to provide minimum guidelines for the healthy moderation of vitamin D, scalable to each of the six Fitzpatrick skin types. PMID:25407011

  2. Managing the technological edge: the UNESCO International Computation Centre and the limits to the transfer of computer technology, 1946-61.

    PubMed

    Nofre, David

    2014-07-01

    The spread of the modern computer is assumed to have been a smooth process of technology transfer. This view relies on an assessment of the open circulation of knowledge ensured by the US and British governments in the early post-war years. This article presents new historical evidence that question this view. At the centre of the article lies the ill-fated establishment of the UNESCO International Computation Centre. The project was initially conceived in 1946 to provide advanced computation capabilities to scientists of all nations. It soon became a prize sought by Western European countries like The Netherlands and Italy seeking to speed up their own national research programs. Nonetheless, as the article explains, the US government's limitations on the research function of the future centre resulted in the withdrawal of European support for the project. These limitations illustrate the extent to which US foreign science policy could operate as (stealth) industrial policy to secure a competitive technological advantage and the prospects of US manufacturers in a future European market. PMID:24908797

  3. Contribution of mono and polysaccharides to heterotrophic N2 fixation at the eastern Mediterranean coastline

    PubMed Central

    Rahav, E.; Giannetto, M. J.; Bar-Zeev, E.

    2016-01-01

    N2 fixation should be a critical process in the nitrogen-poor surface water of the eastern Mediterranean Sea. Despite favorable conditions, diazotroph abundance and N2 fixation rates remains low for reasons yet explained. The main goal of this study was to investigate the limiting nutrients for diazotrophy in this oligotrophic environment. Hence, we conducted dedicated bottle-microcosms with eastern Mediterranean Sea water that were supplemented with mono and polysaccharides as well as inorganic nitrogen and phosphorous. Our results indicate that the diazotrophic community expressing nifH was primarily represented by heterotrophic Proteobacteria. N2 fixation and heterotrophic bacterial activity increased up-to tenfold following two days of dark incubations, once seawater was supplemented with organic carbon substrate in the form of glucose (monosaccharides) or gum-xanthan (polysaccharide surrogate). Furthermore, our results point that carbon-rich polysaccharides, such as transparent exopolymer particles, enhance heterotrophic N2 fixation, by forming microenvironments of intense metabolic activity, high carbon: nitrogen ratio, and possibly low O2 levels. The conclusions of this study indicate that diazotrophs in the eastern Mediterranean coast are primarily limited by organic carbon substrates, as possibly in many other marine regions. PMID:27306501

  4. Interrami intraoral fixation technique for severe mandibular rifle fragmented bullet injury management.

    PubMed

    Shuker, Sabri T

    2013-07-01

    Interrami intraoral Kirschner wire fixation technique is presented for the reduction, stabilization, and immobilization of a pulverized and avulsed lower jaw caused by rifle fragmented bullet injuries. This indirect mandibular war injury fixation technique was tolerated by the patients and tissue more than any indirect external fixation. In addition, it is easier than open reduction using large bone plates for disrupted ballistics mandibular injury defects. An interrami intraoral fixation is appropriate for severely disrupted mandibular hard and soft tissues, and has been adapted in cases of mass casualties and limited resources. Benefits of use include limited hospital beds and fewer follow-up visits. Rifle fragmented bullet injuries need more attention for several reasons: not only because of the higher mortality and devastating nature of the injuries, but also because these injuries are responsible for an unreported type of bullet biomechanism wounding in the craniofacial region. In turn, this necessitates specialized victim management. The survival rates depend on immediate proper execution of airway, breathing, and circulation, which become more complicated as it relates to airway compromise and oropharyngeal hemorrhage resuscitation. Survival is predicated on the implementation of feasible, sensible, life-saving techniques that are applied at the appropriate time. PMID:23851763

  5. Contribution of mono and polysaccharides to heterotrophic N2 fixation at the eastern Mediterranean coastline.

    PubMed

    Rahav, E; Giannetto, M J; Bar-Zeev, E

    2016-01-01

    N2 fixation should be a critical process in the nitrogen-poor surface water of the eastern Mediterranean Sea. Despite favorable conditions, diazotroph abundance and N2 fixation rates remains low for reasons yet explained. The main goal of this study was to investigate the limiting nutrients for diazotrophy in this oligotrophic environment. Hence, we conducted dedicated bottle-microcosms with eastern Mediterranean Sea water that were supplemented with mono and polysaccharides as well as inorganic nitrogen and phosphorous. Our results indicate that the diazotrophic community expressing nifH was primarily represented by heterotrophic Proteobacteria. N2 fixation and heterotrophic bacterial activity increased up-to tenfold following two days of dark incubations, once seawater was supplemented with organic carbon substrate in the form of glucose (monosaccharides) or gum-xanthan (polysaccharide surrogate). Furthermore, our results point that carbon-rich polysaccharides, such as transparent exopolymer particles, enhance heterotrophic N2 fixation, by forming microenvironments of intense metabolic activity, high carbon: nitrogen ratio, and possibly low O2 levels. The conclusions of this study indicate that diazotrophs in the eastern Mediterranean coast are primarily limited by organic carbon substrates, as possibly in many other marine regions. PMID:27306501

  6. Occupational radiation dose to eyes from interventional radiology procedures in light of the new eye lens dose limit from the International Commission on Radiological Protection

    PubMed Central

    Walsh, C; Gallagher, A; Dowling, A; Guiney, M; Ryan, J M; McEniff, N; O'Reilly, G

    2015-01-01

    Objective: In 2011, the International Commission on Radiological Protection (ICRP) recommended a substantial reduction in the equivalent dose limit for the lens of the eye, in line with a reduced threshold of absorbed dose for radiation-induced cataracts. This is of particular relevance in interventional radiology (IR) where it is well established that staff doses can be significant, however, there is a lack of data on IR eye doses in terms of Hp(3). Hp(3) is the personal dose equivalent at a depth of 3 mm in soft tissue and is used for measuring lens dose. We aimed to obtain a reliable estimate of eye dose to IR operators. Methods: Lens doses were measured for four interventional radiologists over a 3-month period using dosemeters specifically designed to measure Hp(3). Results: Based on their typical workloads, two of the four interventional radiologists would exceed the new ICRP dose limit with annual estimated doses of 31 and 45 mSv to their left eye. These results are for an “unprotected” eye, and for IR staff who routinely wear lead glasses, the dose beneath the glasses is likely to be significantly lower. Staff eye dose normalized to patient kerma–area product and eye dose per procedure have been included in the analysis. Conclusion: Eye doses to IR operators have been established using a dedicated Hp(3) dosemeter. Estimated annual doses have the potential to exceed the new ICRP limit. Advances in knowledge: We have estimated lens dose to interventional radiologists in terms of Hp(3) for the first time in an Irish hospital setting. PMID:25761211

  7. Inverted Internal Limiting Membrane Flap Technique for Repair of Large Macular Holes: A Short-term Follow-up of Anatomical and Functional Outcomes

    PubMed Central

    Chen, Zhe; Zhao, Chan; Ye, Jun-Jie; Wang, Xu-Qian; Sui, Rui-Fang

    2016-01-01

    Background: Inverted internal limiting membrane (ILM) flap technique has recently been reported in a limited number of studies as an effective surgical technique for the management of large macular holes (MHs) with fair MH closure rates as well as gains in visual acuity. In the current study, longitudinal changes in multi-focal electroretinogram (mfERG) responses, best-corrected visual acuity (BCVA) and spectral-domain optical coherence tomography (SD-OCT) were evaluated in eyes with large MHs managed by this technique. Methods: A prospective noncontrolled interventional study of eight patients (eight eyes) with large MHs (minimum diameter >400 μm) was conducted. All MHs were treated with pars plana vitrectomy and indocyanine green-assisted inverted ILM flap technique. SD-OCT images were used to assess the anatomical outcomes of surgery while BCVA and mfERG were used to evaluate the functional outcomes during a 3-month follow-up. Results: All patients underwent successful intended manipulation and translocation of the ILM flap without flap dislocation and achieved complete anatomical closure. Partial microstructural reconstruction, demonstrated on SD-OCT as restoration of the external limiting membrane and the ellipsoid zone, was observed in all cases as early as 1 month after surgery. Functionally, as compared to baseline, all patients showed improvements in BCVA and all but one in mfERG response during follow-up. However, Pearson's test revealed no significant correlations between BCVA and mfERG responses of the fovea and of the macular area at each evaluation time point. Conclusions: Inverted ILM flap technique appeares to be a safe and effective approach for the management of large idiopathic MHs with favorable short-term anatomical and functional results. Postoperative reconstruction of the microstructure generally shows good consistency with improvements in both BCVA and mfERG response, of which the latter might be a supplement for the former in

  8. Suture Button Fixation Treatment of Chronic Lisfranc Injury in Professional Dancers and High-Level Athletes.

    PubMed

    Charlton, Timothy; Boe, Chelsea; Thordarson, David B

    2015-12-01

    Chronic Lisfranc injury is a subtle and severe injury in high-level athletes, including dancers. This patient population is generally intolerant of intra-articular screw fixation and can develop significant post-traumatic arthritis with potentially career ending complications. Flexible fixation with suture-button devices provides potential restoration of physiologic motion at the joint, with appropriate support for healing that may facilitate return to en pointe activities for dancers. We hypothesized that the suture-button device would restore motion at the Lisfranc joint and allow for return to activities in this particular population without the limitations and complications of rigid fixation. We operated on seven dancers and high-level athletes with diagnosed Lisfranc injuries by installing a suture-button device. All patients had failed conservative management after late presentation. They were allowed to return to sport in 6 months, preoperative and postoperative American Orthopaedic Foot and Ankle Score (AOFAS) foot scores were obtained, and patients were followed for a minimum of 15 months. All seven returned to full activities in 6 months, with radiographic evidence of fixation and no complications to date. AOFAS foot scores improved from an average of 65 preoperatively to an average of 97 postoperatively at latest follow-up. It is concluded that flexible fixation with suture-button type device represents a viable alternative to screw fixation or fusion that may allow dancers and athletes to return to previous levels of activity after Lisfranc injury. This case series represents to our knowledge the first application of this device to a unique population that requires flexibility at the Lisfranc joint for performance. PMID:26641700

  9. Fixation performance of an ultrasonically fused, bioresorbable osteosynthesis implant: A biomechanical and biocompatibility study.

    PubMed

    Augat, P; Robioneck, P B; Abdulazim, A; Wipf, F; Lips, K S; Alt, V; Schnettler, R; Heiss, C

    2016-01-01

    Bioresorbable implants may serve as an alternative option for the fixation of bone fractures. Because of their minor inherent mechanical properties and insufficient anchorage within bone bioresorbable implants have so far been limited to mechanically nondemanding fracture types. By briefly liquefying the surface of the biomaterial during insertion, bioresorbable implants can be ultrasonically fused with bone to improve their mechanical fixation. The objective of this study was to investigate the biomechanical fixation performance and in vivo biocompatibility of an ultrasonically fused bioresorbable polymeric pin (SonicPin). First, we biomechanically compared the fused pin with press fitted metallic and bioresorbable polymeric implants for quasi-static and fatigue strength under shear and tensile loading in a polyurethane foam model. Second, fused implants were inserted into cancellous bovine bone and tested biomechanically to verify the reproducibility of their fusion behavior. Finally, the fused pins were tested in a lapine model of femoral condyle osteotomies and were histologically examined by light and transmission electron microscopy. While comparable under static shear loads, fixation performance of ultrasonically fused pins was significantly (p = 0.001) stronger under tensile loading than press fit implants and showed no pull-out. Both bioresorbable implants withstood comparable fatigue shear strength, but less than the K-wire. In bovine bone the ultrasonic fusion process worked highly reproducible and provided consistent mechanical fixation. In vivo, the polymeric pin produced no notable foreign body reactions or resorption layers. Ultrasonic fusion of polymeric pins achieved adequate and consistent mechanical fixation with high reproducibility and exhibits good short-term resorption and biocompatibility. PMID:25678144

  10. A Simple, High-Precision, High-Sensitivity Tracer Assay for N(inf2) Fixation

    PubMed Central

    Montoya, J. P.; Voss, M.; Kahler, P.; Capone, D. G.

    1996-01-01

    We describe a simple, precise, and sensitive experimental protocol for direct measurement of N(inf2) fixation using the conversion of (sup15)N(inf2) to organic N. Our protocol greatly reduces the limit of detection for N(inf2) fixation by taking advantage of the high sensitivity of a modern, multiple-collector isotope ratio mass spectrometer. This instrument allowed measurement of N(inf2) fixation by natural assemblages of plankton in incubations lasting several hours in the presence of relatively low-level (ca. 10 atom%) tracer additions of (sup15)N(inf2) to the ambient pool of N(inf2). The sensitivity and precision of this tracer method are comparable to or better than those associated with the C(inf2)H(inf2) reduction assay. Data obtained in a series of experiments in the Gotland Basin of the Baltic Sea showed excellent agreement between (sup15)N(inf2) tracer and C(inf2)H(inf2) reduction measurements, with the largest discrepancies between the methods occurring at very low fixation rates. The ratio of C(inf2)H(inf2) reduced to N(inf2) fixed was 4.68 (plusmn) 0.11 (mean (plusmn) standard error, n = 39). In these experiments, the rate of C(inf2)H(inf2) reduction was relatively insensitive to assay volume. Our results, the first for planktonic diazotroph populations of the Baltic, confirm the validity of the C(inf2)H(inf2) reduction method as a quantitative measure of N(inf2) fixation in this system. Our (sup15)N(inf2) protocols are comparable to standard C(inf2)H(inf2) reduction procedures, which should promote use of direct (sup15)N(inf2) fixation measurements in other systems. PMID:16535283

  11. Climatic and Grazing Controls on Biological Soil Crust Nitrogen Fixation in Semi-arid Ecosystems

    NASA Astrophysics Data System (ADS)

    Schwabedissen, S. G.; Reed, S.; Lohse, K. A.; Magnuson, T. S.

    2014-12-01

    Nitrogen, next to water, is believed to be the main limiting resource in arid and semi-arid ecosystems. Biological soil crusts (biocrusts) -a surface community of mosses, lichens and cyanobacteria-have been found to be the main influx of "new" nitrogen (N) into many dryland ecosystems. Controls on biocrust N fixation rates include climate (temperature and moisture), phosphorus availability, and disturbance factors such as trampling, yet a systematic examination of climatic and disturbance controls on biocrusts communities is lacking. Biocrust samples were collected along an elevation gradient in the Reynolds Creek Experimental Watershed near Murphy, Idaho. Four sites were selected from a sagebrush steppe ecosystem with precipitation ranging from ≤250mm/yr to ≥1100mm/yr. Each site included 5 grazed plots and one historic exclosure plot that has been free from grazing for more than 40 years. Five samples each were collected from under plants and from interplant spaces from the grazed plots and exclosures and analyzed for potential N fixation using an acetylene reduction assay. We hypothesized that N fixation rates would be the highest in the exclosures of the two middle sites along the elevation gradient, due to the lack of disturbance and optimal temperature and moisture, respectively. As predicted, results showed higher rates of potential N fixation in exclosures than non-exclosures at a mid-elevation 8.4 ± 3.1 kg N/ha/yr in the exclosures compared to 1.8 ± 1.5 kg N/ha/yr indicating that grazing may reduce N fixation activity. Interestingly, rates were 2-5 times lower under plant canopies compared to interplant spaces at all but the highest elevation site. Findings from our study suggest that biocrust N fixation may be a dominant input of N into theses dryland systems and, in line with our hypotheses, that climate, location within the landscape, and disturbance may interact to regulate the rates of this fundamental ecosystem process.

  12. Use of Ilizarov Fixator for Grade III B Open Olecranon Fracture: a Case Report and Surgical Technique

    PubMed Central

    Sharad Nemade, Pradip; Dash, Kumar Kaushik; Patwardhan, Tanvi Yeshwant; Londhe, Pravin Vasant

    2015-01-01

    Introduction: External fixator application can be difficult for olecranon fractures in presence of large degloving injuries. We describe use of simple Ilizarov ring fixator construct for grade IIIB open olecranon fracture management. Case Report: A 45-year-old female with Grade III B open comminuted olecranon fracture (30*15cm degloving area) and ulnar nerve palsy was treated with a novel ring fixator construct. Two cut-end olive wires were passed from the proximal olecranon across the fracture site in intramedullary fashion exiting dorsally at mid-ulnar level through healthy skin and were attached to an Ilizarov half ring secured by perpendicular wires. The olive wires were tensioned, achieving compression and stability. Range of motion (ROM) exercises could be started quickly as the elbow was not spanned. Wound healed after skin grafting and at one-year follow-up the patient has good functional results (PRE 7, DASH 9.48), elbow ROM 10°-130°, 75° pronation and 85° supination. The patient returned to pre-injury occupational activities and had no pain. At three-year follow-up, the x-ray and CT showed union of olecranon fragment with well-maintained congruency. Conclusion: Internal fixation in most cases may be precluded by the soft tissue trauma and risk of infection. In addition, the small proximal fragment precludes a stable external fixation. In this technique, the hardware is kept away from the open wound allowing better wound inspection and care. The intramedullary olive wires provide compression and stability, and thus allow early ROM. Ilizarov half-ring and olive wire fixation can be an useful option for management of high grade open olecranon fractures because of its advantages, viz. stable fixation, minimal internal hardware, optimal wound care, immediate initiation of range of motion, and good outcome. PMID:27299012

  13. In vitro biomechanical evaluation of sagittal split osteotomy fixation with a specifically designed miniplate.

    PubMed

    Pereira Filho, V A; Iamashita, H Y; Monnazzi, M S; Gabrielli, M F R; Vaz, L G; Passeri, L A

    2013-03-01

    Recent studies have evaluated many methods of internal fixation for sagittal split ramus osteotomy (SSRO), aiming to increase stability of the bone segments while minimizing condylar displacement. The purpose of this study was to evaluate, through biomechanical testing, the stability of the fixation comparing a specially designed bone plate to other two commonly used methods. Thirty hemimandibles were separated into three equal groups. All specimens received SSRO. In Group I the osteotomies were fixed with three 15 mm bicortical positional screws in an inverted-L pattern with an insertion angle of 90°. In Group II, fixation was carried out with a four-hole straight plate and four 6mm monocortical screws. In Group III, fixation was performed with an adjustable sagittal plate and eight 6mm monocortical screws. Hemimandibles were submitted to vertical compressive loads, by a mechanical testing unit. Averages and standard deviations were submitted to analysis of variance using the Tukey test with a 5% level of significance. Bicortical screws presented the greatest values of loading resistance. The adjustable miniplate demonstrated 60% lower resistance compared to bicortical screws. Group II presented on average 40% less resistant to the axial loading. PMID:22898312

  14. Nitrogen fixation in a non-heterocystous cyanobacterial mat from a mountain river

    NASA Astrophysics Data System (ADS)

    Berrendero, Esther; Valiente, Eduardo Fernández; Perona, Elvira; Gómez, Claudia L.; Loza, Virginia; Muñoz-Martín, M. Ángeles; Mateo, Pilar

    2016-08-01

    In situ nitrogen fixation was investigated in a cyanobacterial mat growing on the bed of rocks of the Muga River, Spain. The filamentous non-heterocystous cyanobacterium Schizothrix dominated the mat, showing nitrogenase activity in the light at similar rates to those found in nearby heterocystous Rivularia colonies. N2 fixation in the light was significantly increased by an inhibitor of PSII and oxygen evolution, DCMU (3-[3,4-dichlorophenyl]-1,1-dimethylurea), and anaerobic conditions. However, no nitrogenase activity was found in the dark. Addition of fructose as a respiratory substrate induced nitrogenase activity in samples incubated under aerobic conditions in the dark but not in anaerobic conditions. Microelectrode oxygen profiles showed internal microaerobic microzones where nitrogen fixation might concentrate. Analyses of the 16S rRNA gene revealed only the presence of sequences belonging to filamentous non-heterocystous cyanobacteria. nifH gene diversity showed that the major phylotypes also belonged to this group. One of the three strains isolated from the Schizothrix mat was capable of fixing N2 and growing in the absence of combined N. This was consistent with the nifH gene analysis. These results suggest a relevant contribution of non-heterocystous cyanobacteria to nitrogen fixation in these mats.

  15. A Novel Technique for Closed Reduction and Fixation of Paediatric Calcaneal Fracture Dislocation Injuries

    PubMed Central

    Faroug, Radwane; Stirling, Paul; Ali, Farhan

    2013-01-01

    Paediatric calcaneal fractures are rare injuries usually managed conservatively or with open reduction and internal fixation (ORIF). Closed reduction was previously thought to be impossible, and very few cases are reported in the literature. We report a new technique for closed reduction using Ilizarov half-rings. We report successful closed reduction and screwless fixation of an extra-articular calcaneal fracture dislocation in a 7-year-old boy. Reduction was achieved using two Ilizarov half-ring frames arranged perpendicular to each other, enabling simultaneous application of longitudinal and rotational traction. Anatomical reduction was achieved with restored angles of Bohler and Gissane. Two K-wires were the definitive fixation. Bony union with good functional outcome and minimal pain was achieved at eight-weeks follow up. ORIF of calcaneal fractures provides good functional outcome but is associated with high rates of malunion and postoperative pain. Preservation of the unique soft tissue envelope surrounding the calcaneus reduces the risk of infection. Closed reduction prevents distortion of these tissues and may lead to faster healing and mobilisation. Closed reduction and screwless fixation of paediatric calcaneal fractures is an achievable management option. Our technique has preserved the soft tissue envelope surrounding the calcaneus, has avoided retained metalwork related complications, and has resulted in a good functional outcome. PMID:23819090

  16. Nitrogen fixation in a non-heterocystous cyanobacterial mat from a mountain river.

    PubMed

    Berrendero, Esther; Valiente, Eduardo Fernández; Perona, Elvira; Gómez, Claudia L; Loza, Virginia; Muñoz-Martín, M Ángeles; Mateo, Pilar

    2016-01-01

    In situ nitrogen fixation was investigated in a cyanobacterial mat growing on the bed of rocks of the Muga River, Spain. The filamentous non-heterocystous cyanobacterium Schizothrix dominated the mat, showing nitrogenase activity in the light at similar rates to those found in nearby heterocystous Rivularia colonies. N2 fixation in the light was significantly increased by an inhibitor of PSII and oxygen evolution, DCMU (3-[3,4-dichlorophenyl]-1,1-dimethylurea), and anaerobic conditions. However, no nitrogenase activity was found in the dark. Addition of fructose as a respiratory substrate induced nitrogenase activity in samples incubated under aerobic conditions in the dark but not in anaerobic conditions. Microelectrode oxygen profiles showed internal microaerobic microzones where nitrogen fixation might concentrate. Analyses of the 16S rRNA gene revealed only the presence of sequences belonging to filamentous non-heterocystous cyanobacteria. nifH gene diversity showed that the major phylotypes also belonged to this group. One of the three strains isolated from the Schizothrix mat was capable of fixing N2 and growing in the absence of combined N. This was consistent with the nifH gene analysis. These results suggest a relevant contribution of non-heterocystous cyanobacteria to nitrogen fixation in these mats. PMID:27476439

  17. Nitrogen fixation in a non-heterocystous cyanobacterial mat from a mountain river

    PubMed Central

    Berrendero, Esther; Valiente, Eduardo Fernández; Perona, Elvira; Gómez, Claudia L.; Loza, Virginia; Muñoz-Martín, M. Ángeles; Mateo, Pilar

    2016-01-01

    In situ nitrogen fixation was investigated in a cyanobacterial mat growing on the bed of rocks of the Muga River, Spain. The filamentous non-heterocystous cyanobacterium Schizothrix dominated the mat, showing nitrogenase activity in the light at similar rates to those found in nearby heterocystous Rivularia colonies. N2 fixation in the light was significantly increased by an inhibitor of PSII and oxygen evolution, DCMU (3-[3,4-dichlorophenyl]-1,1-dimethylurea), and anaerobic conditions. However, no nitrogenase activity was found in the dark. Addition of fructose as a respiratory substrate induced nitrogenase activity in samples incubated under aerobic conditions in the dark but not in anaerobic conditions. Microelectrode oxygen profiles showed internal microaerobic microzones where nitrogen fixation might concentrate. Analyses of the 16S rRNA gene revealed only the presence of sequences belonging to filamentous non-heterocystous cyanobacteria. nifH gene diversity showed that the major phylotypes also belonged to this group. One of the three strains isolated from the Schizothrix mat was capable of fixing N2 and growing in the absence of combined N. This was consistent with the nifH gene analysis. These results suggest a relevant contribution of non-heterocystous cyanobacteria to nitrogen fixation in these mats. PMID:27476439

  18. A Pediatric Comminuted Talar Fracture Treated by Minimal K-Wire Fixation Without Using a Tourniquet

    PubMed Central

    Inal, Sermet; Inal, Canan

    2014-01-01

    Background Pediatric comminuted talar fractures are reported to be rare, and treatment options such as minimal internal K-wire fixation without using a tourniquet to prevent avascular necrosis have not previously been investigated. Case Description We report a case of a comminuted talar body and a non-displaced neck fracture with dislocation of the tibiotalar, talonavicular and subtalar joints with bimalleolar epiphyseal fractures in an 11-year-old boy due to a fall from height. We present radiological findings, the surgical procedure and clinical outcomes of minimal internal K-wire fixation without using a tourniquet. Literature Review Avascular necrosis rates are reported to be between 0 % and 66 % after fractures of the neck of the talus and the talar body in children. The likelihood of developing avascular necrosis increases with the severity of the fracture. Clinical Relevance To avoid avascular necrosis in a comminuted talar fracture accompanied by tibiotalar, talonavicular, subtalar dislocations and bimalleolar epiphyseal fractures, a minimal internal K-wire fixation without the use of a tourniquet was performed. The outcome was evaluated by the American Orthopedic Foot and Ankle Society score (AOFAS). A score of 90 (excellent) was found at the end of the second year of follow up. Radiology revealed preservation of the joint with no evidence of avascular necrosis, and clinical findings revealed a favorable functional outcome after two years. Level of Evidence 4 PMID:25328479

  19. Local Structure Fixation in the Composite Manufacturing Chain

    NASA Astrophysics Data System (ADS)

    Girdauskaite, Lina; Krzywinski, Sybille; Rödel, Hartmut; Wildasin-Werner, Andrea; Böhme, Ralf; Jansen, Irene

    2010-12-01

    Compared to metal materials, textile reinforced composites show interesting features, but also higher production costs because of low automation rate in the manufacturing chain at this time. Their applicability is also limited due to quality problems, which restrict the production of complex shaped dry textile preforms. New technologies, design concepts, and cost-effective manufacturing methods are needed in order to establish further fields of application. This paper deals with possible ways to improve the textile deformation process by locally applying a fixative to the structure parallel to the cut. This hinders unwanted deformation in the textile stock during the subsequent stacking and formation steps. It is found that suitable thermoplastic binders, applied in the appropriate manner do not restrict formation of the textile and have no negative influence on the mechanical properties of the composite.

  20. Environmental Forcing of Nitrogen Fixation in the Eastern Tropical and Sub-Tropical North Atlantic Ocean

    PubMed Central

    Rijkenberg, Micha J. A.; Langlois, Rebecca J.; Mills, Matthew M.; Patey, Matthew D.; Hill, Polly G.; Nielsdóttir, Maria C.; Compton, Tanya J.; LaRoche, Julie; Achterberg, Eric P.

    2011-01-01

    During the winter of 2006 we measured nifH gene abundances, dinitrogen (N2) fixation rates and carbon fixation rates in the eastern tropical and sub-tropical North Atlantic Ocean. The dominant diazotrophic phylotypes were filamentous cyanobacteria, which may include Trichodesmium and Katagnymene, with up to 106 L−1 nifH gene copies, unicellular group A cyanobacteria with up to 105 L−1 nifH gene copies and gamma A proteobacteria with up to 104 L−1 nifH gene copies. N2 fixation rates were low and ranged between 0.032–1.28 nmol N L−1 d−1 with a mean of 0.30±0.29 nmol N L−1 d−1 (1σ, n = 65). CO2-fixation rates, representing primary production, appeared to be nitrogen limited as suggested by low dissolved inorganic nitrogen to phosphate ratios (DIN:DIP) of about 2±3.2 in surface waters. Nevertheless, N2 fixation rates contributed only 0.55±0.87% (range 0.03–5.24%) of the N required for primary production. Boosted regression trees analysis (BRT) showed that the distribution of the gamma A proteobacteria and filamentous cyanobacteria nifH genes was mainly predicted by the distribution of Prochlorococcus, Synechococcus, picoeukaryotes and heterotrophic bacteria. In addition, BRT indicated that multiple a-biotic environmental variables including nutrients DIN, dissolved organic nitrogen (DON) and DIP, trace metals like dissolved aluminum (DAl), as a proxy of dust inputs, dissolved iron (DFe) and Fe-binding ligands as well as oxygen and temperature influenced N2 fixation rates and the distribution of the dominant diazotrophic phylotypes. Our results suggest that lower predicted oxygen concentrations and higher temperatures due to climate warming may increase N2 fixation rates. However, the balance between a decreased supply of DIP and DFe from deep waters as a result of more pronounced stratification and an enhanced supply of these nutrients with a predicted increase in deposition of Saharan dust may ultimately determine the consequences of climate

  1. Mesh fixation alternatives in laparoscopic ventral hernia repair.

    PubMed

    Muysoms, Filip E; Novik, Bengt; Kyle-Leinhase, Iris; Berrevoet, Frederik

    2012-12-01

    Since the introduction of laparoscopic ventral hernia repair, there has been an ongoing dispute over the optimal method of fixating the mesh against the abdominal wall. In general, one could say that the more penetrating the fixation used, the stronger the fixation, but at the cost of increased acute postoperative pain. The occurrence of chronic pain in some patients has led to the search for less permanent penetrating fixation, but without risking a less stable mesh fixation and increased recurrences due to shift or shrinkage of the mesh. Avoiding transfascial sutures by using a double crown of staples has been proposed and recently absorbable fixation devices have been developed. Some surgeons have proposed fixation with glue to reduce the number of staples, or even eliminate them entirely. The continuously increasing multitude of marketed meshes and fixating devices leads to unlimited options in mesh fixation combination and geometry. Therefore, we will never be able to get a clear view on the benefits and pitfalls of every specific combination. Clearance of the anterior abdominal wall from peritoneal fatty tissue and correct positioning of the mesh with ample overlap of the hernia defect are possibly as important as the choice of mesh and fixation. Other topics that are involved in successful outcomes but not addressed in this article are adequate training in the procedure, appropriate selection of patients, and careful adhesiolysis to minimize accidental visceral injuries. PMID:23225589

  2. New insights into the evolutionary history of biological nitrogen fixation

    PubMed Central

    Boyd, Eric S.; Peters, John W.

    2013-01-01

    Nitrogenase, which catalyzes the ATP-dependent reduction of dinitrogen (N2) to ammonia (NH3), accounts for roughly half of the bioavailable nitrogen supporting extant life. The fundamental requirement for fixed forms of nitrogen for life on Earth, both at present and in the past, has led to broad and significant interest in the origin and evolution of biological N2 fixation. One key question is whether the limited availability of fixed nitrogen was a factor in life's origin or whether there were ample sources of fixed nitrogen produced by abiotic processes or delivered through the weathering of bolide impact materials to support this early life. If the latter, the key questions become what were the characteristics of the environment that precipitated the evolution of this oxygen sensitive process, when did this occur, and how was its subsequent evolutionary history impacted by the advent of oxygenic photosynthesis and the rise of oxygen in the Earth's biosphere. Since the availability of fixed sources of nitrogen capable of supporting early life is difficult to glean from the geologic record, there are limited means to get direct insights into these questions. Indirect insights, however, can be gained through phylogenetic studies of nitrogenase structural gene products and additional gene products involved in the biosynthesis of the complex metal-containing prosthetic groups associated with this enzyme complex. Insights gained from such studies, as reviewed herein, challenge traditional models for the evolution of biological nitrogen fixation and provide the basis for the development of new conceptual models that explain the stepwise evolution of this highly complex life sustaining process. PMID:23935594

  3. Sinus tarsi approach with trans-articular fixation for displaced intra-articular fractures of the calcaneus.

    PubMed

    Ebraheim, N A; Elgafy, H; Sabry, F F; Freih, M; Abou-Chakra, I S

    2000-02-01

    The charts and radiographs of 99 patients with 106 intraarticular fractures of the calcaneus were retrospectively reviewed. There were 75 men and 24 women. The average age was forty-two (range, 17 to 81). Fifty-seven of the fractures were left and 49 were right. The mechanism of injury was a fall from a height in 69 patients and motor vehicle accident in 30 patients. According to Sanders classification, seventy-one cases (67%) had type II fractures, 25 cases (23.6%) had type III, and ten cases (9.4%) had type IV. All the patients had operative management through a limited sinus tarsi approach with minimal fixation of the fracture with one or several pins. One of the pins was usually applied from the talus to the calcaneus through the fracture after reduction of the posterior facet. Nine cases (8.5%) developed postoperative infection, four cases (3.8%) had superficial wound infection, four cases (3.8%) had pin tract infection and one case (0.9%) had osteomylitis. Our follow-up at an average of 29 months (range, 12 to 84 months) showed that the American Orthopedic Foot and Ankle Society, Ankle-Hindfoot Score for the all group was 77.6 (range, 31-91). Forty-one fractures (38.8%) were graded excellent, 39 fractures (36.7%) good, 14 fractures (13.2%) fair, and 12 fractures (11.3%) were failures. Although radiological degenerative changes in the subtalar joint were seen in 41 cases (38.7%), only six cases (5.6%) required subsequent subtalar fusion. The authors conclude that the operative method used in the current study which followed the principle of minimal soft tissue damage and minimal internal fixation may be a good option for management of calcaneus fractures. PMID:10694021

  4. Rib Fracture Fixation Restores Inspiratory Volume and Peak Flow in a Full Thorax Human Cadaveric Breathing Model

    PubMed Central

    Slobogean, Gerard P.; Kim, Hyunchul; Russell, Joseph P.; Stockton, David J.; Hsieh, Adam H.; O’Toole, Robert V.

    2015-01-01

    Background: Multiple rib fractures cause significant pain and potential for chest wall instability. Despite an emerging trend of surgical management of flail chest injuries, there are no studies examining the effect of rib fracture fixation on respiratory function. Objectives: Using a novel full thorax human cadaveric breathing model, we sought to explore the effect of flail chest injury and subsequent rib fracture fixation on respiratory outcomes. Patients and Methods: We used five fresh human cadavers to generate negative breathing models in the left thorax to mimic physiologic respiration. Inspiratory volumes and peak flows were measured using a flow meter for all three chest wall states: intact chest, left-sided flail chest (segmental fractures of ribs 3 - 7), and post-fracture open reduction and internal fixation (ORIF) of the chest wall with a pre-contoured rib specific plate fixation system. Results: A wide variation in the mean inspiratory volumes and peak flows were measured between specimens; however, the effect of a flail chest wall and the subsequent internal fixation of the unstable rib fractures was consistent across all samples. Compared to the intact chest wall, the inspiratory volume decreased by 40 ± 19% in the flail chest model (P = 0.04). Open reduction and internal fixation of the flail chest returned the inspiratory volume to 130 ± 71% of the intact chest volumes (P = 0.68). A similar 35 ± 19% decrease in peak flows was seen in the flail chest (P = 0.007) and this returned to 125 ± 71% of the intact chest following ORIF (P = 0.62). Conclusions: Negative pressure inspiration is significantly impaired by an unstable chest wall. Restoring mechanical stability of the fractured ribs improves respiratory outcomes similar to baseline values. PMID:26848471

  5. Analysis of operational, institutional and international limitations for alternative fuel vehicles and technologies: Means/methods for implementing changes. [Public fleet groups--information needs

    SciTech Connect

    Not Available

    1992-07-01

    This project focused upon the development of an approach to assist public fleet managers in evaluating the characteristics and availability of alternative fuels (AF's) and alternative fuel vehicles (AFV's) that will serve as possible replacements for vehicles currently serving the needs of various public entities. Also of concern were the institutional/international limitations for alternative fuels and alternative fuel vehicles. The City of Detroit and other public agencies in the Detroit area were the particular focus for the activities. As the development and initial stages of use of alternative fuels and alternative fuel vehicles proceeds, there will be an increasing need to provide information and guidance to decision-makers regarding differences in requirements and features of these fuels and vehicles. There wig be true differences in requirements for servicing, managing, and regulating. There will also be misunderstanding and misperception. There have been volumes of data collected on AFV'S, and as technology is improved, new data is constantly added. There are not, however, condensed and effective sources of information for public vehicle fleet managers on vehicle and equipment sources, characteristics, performance, costs, and environmental benefits. While theoretical modeling of public fleet requirements has been done, there do not seem to be readily available practical''. There is a need to provide the best possible information and means to minimize the problems for introducing the effective use of alternative fuels and alternative fuel vehicles.

  6. Will rising CO2 influence how nutrients interact to control tropical N2-fixation?

    NASA Astrophysics Data System (ADS)

    Trierweiler, A.; Winter, K.; Wright, S. J.; Wurzburger, N.; Hedin, L.

    2013-12-01

    The response of terrestrial tropical carbon sinks to increasing CO2 is a pressing question in biogeochemistry. Limitation of nutrients such as N may constrain these sinks. Biological N2-fixation, an important biogeochemical process that provides new nitrogen to ecosystems, potentially plays an important role in supporting tropical carbon sinks. Despite the importance of N2-fixation to the linked nitrogen and carbon cycles, we know little about how nutrient limitation of the process of biological N2-fixation, itself, will affect tropical fixation and N2-fixing plants. While rising CO2 levels may increase tree growth and N2-fixation when nutrients are abundant, at the same time, the increased growth may force N2-fixing plants into phosphorus (P) and molybdenum (Mo) limitation, both elements that are scarce in tropical forests and critical to N2-fixers. This study improves our understanding on what controls fixation through a series of greenhouse and in situ field experiments. First, we used a greenhouse experiment where we manipulated CO2 levels combined with a field study in forest gaps. In the greenhouse study we grew a N2-fixing seedling and a non-fixing seedling at pre-industrial (280 ppm), current (400 ppm), and double (800 ppm) CO2 concentrations with and without P, Mo, or both. In the year-long field study, we applied the same nutrient treatments to seedlings planting in natural light gaps and ambient CO2. To supplement our year-long seedling experiment, we also examined 11 years of growth data from a long-term N x P x K factorial fertilization experiment also on the Gigante Peninsula. In the greenhouse study, we found nutrient limitation was minimal at pre-industrial CO2 levels, but that limitation appeared with increasing CO2. Phosphorus limitation of tree growth and N2-fixation significantly increased with higher CO2. The additions of Mo and P together allowed for even greater growth and fixation, suggesting Mo-P co-limitation at elevated CO2. Compared to

  7. C1-c2 pedicle screw fixation for treatment of old odontoid fractures.

    PubMed

    Qi, Lei; Li, Mu; Zhang, Shuai; Si, Haipeng; Xue, Jingsong

    2015-02-01

    Nonunion and C1-C2 instability of odontoid fractures usually result from delayed diagnosis and inappropriate treatment. However, the available treatment options for odontoid fractures remain controversial. The authors evaluated the effectiveness of internal screw fixation via the C1 and C2 pedicle in cases of old odontoid fractures. This retrospective study included 21 patients with old odontoid fractures (13 men and 8 women; mean age, 46.5 years; range, 24-69 years). Internal screw fixation via the C1 and C2 pedicle was performed in all patients. Fracture reduction and C1-C2 fusion were assessed with imaging. The neck pain visual analog scale score and cervical spinal cord functional Japanese Orthopaedic Association score (for those who had cervical spinal cord injury) were used to evaluate the effectiveness of treatment. Postoperative complications were recorded. Postoperative imaging showed that the C1-C2 dislocation was satisfactorily repositioned in all patients. Bone fusion was observed 1 year after surgery in all patients. No loosening or breaking of internal fixation occurred. The preoperative neck pain visual analog scale score was 5.9±1.5 and improved significantly to 1.8±0.8 after surgery (P<.001). The Japanese Orthopaedic Association score in patients with cervical spinal injury (n=14) was 9.2±1.9 and also significantly improved to 13.8±1.9 at the last follow-up examination (P<.001), with an average improvement rate of 61.0%. No iatrogenic vertebral artery injury or severe spinal cord injury occurred. Screw fixation via the C1 and C2 pedicle was found to be an effective and safe surgical approach for the treatment of old odontoid fractures with C1-C2 dislocation or instability. PMID:25665108

  8. Effect of Interactions Among Algae on Nitrogen Fixation by Blue-Green Algae (Cyanobacteria) in Flooded Soils

    PubMed Central

    Wilson, John T.; Greene, Sarah; Alexander, Martin

    1979-01-01

    Nitrogen fixation (C2H2 reduction) by algae in flooded soil was limited by interactions within the algal community. Nitrogen fixation by either indigenous algae or Tolypothrix tenuis was reduced severalfold by a dense suspension of the green alga Nephrocytium sp. Similarly, interactions between the nitrogen-fixing alga (cyanobacterium) Aulosira 68 and natural densities of indigenous algae limited nitrogen-fixing activity in one of two soils examined. This was demonstrated by developing a variant of Aulosira 68 that was resistant to the herbicide simetryne at concentrations that prevented development of indigenous algae. More nitrogen was fixed by the resistant variant in flooded soil containing herbicide than was fixed in herbicide-free soil by either the indigenous algae or indigenous algae plus the parent strain of Aulosira. Interference from indigenous algae may hamper the development of nitrogen-fixing algae introduced into rice fields in attempts to increase biological nitrogen fixation. PMID:16345463

  9. Quantifying the effect of fire disturbance on free-living nitrogen fixation in tropical ecosystems

    NASA Astrophysics Data System (ADS)

    De Oliveira Bomfim, B.; Silva, L. C. R.; Marimon-Junior, B. H.; Marimon, B.; Horwath, W. R.; Neves, L.

    2015-12-01

    Tropical forests and savannas are among the most important biomes on Earth, supporting more than half of all plant and animal species on the planet. Despite growing interest in biogeochemical processes that affect tropical forest dynamics, many, including biological nitrogen fixation (BNF), are still poorly understood. Free-living N-fixers are thought to play a key role in tropical ecosystems, alleviating N and P limitation, supporting above and below ground biomass production, as well as carbon storage in plants and soil, but this influence has yet to be quantified. Of particular interest, the spatial distribution and identity of free-living BNF under disturbance regimes that commonly lead to the conversion of forests to savannas is currently unknown. To address this critical gap in knowledge, we measured free-living BNF quantifying rates of N fixation under contrasting fire regimes in the Amazon-Cerrado transition of central Brazil. Samples were collected in 4 ha of floodable forests affected by fire and 1 ha of unburned (seasonally flooded) forest located at the Araguaia State Park, Mato Grosso State, Brazil. Free-living N-fixation rates were measured by both 15N2 (98 atom% 15N) and acethylene reduction assay (ARA). Samples were incubated in the field and left in the dark at room temperature for 12 hours. In the next few weeks we will quantify N fixation rates that will be presented in the upcoming AGU meeting.

  10. Percutaneous Transpedicular Fixation: Technical tips and Pitfalls of Sextant and Pathfinder Systems

    PubMed Central

    Hassan, Ahmed Salah Aldin

    2016-01-01

    Study Design The efficacy of the operative techniques, possible benefits as well as pitfalls and limitations of the techniques are discussed. Potential drawbacks are also detected. Purpose This study aims to report indications, techniques, and our experience with the use of the Sextant and PathFinder percutaneous transpedicular screw fixation systems. Overview of Literature Percutaneous pedicle screw insertion is a novel technique. Successful percutaneous placement of pedicle screws requires surgical skill and experience because of lack of anatomic surface landmarks. Fluoroscopy-guided percutaneous placement of pedicle screws is effective. Many systems are now available. Methods We conducted a prospective operative and postoperative analysis of 40 patients with absolute indication for thoracic or lumbar instability between January 2009 and June 2013. All procedures were performed with the Sextant (group A) and PathFinder (group B) systems under fluoroscopic guidance. Operative techniques are discussed and the results compared. Results Percutaneous transpedicular screw fixation minimizes the morbidity associated with open techniques without compromising the quality of fixation. A total of 190 screws were inserted. There was no additional morbidity. Postoperative computed tomography images and plain X-rays were analyzed. Reduction of visual analog scale scores of back pain was evident. Conclusions Fluoroscopy-guided percutaneous pedicular screws are feasible and can be safely done. Current systems allow multi-segmental fixation with significantly less difficulties. The described techniques have acceptable intra- and postoperative complication rates, and overall sufficient pain control with early mobilization of patients. PMID:26949466

  11. Key role of symbiotic dinitrogen fixation in tropical forest secondary succession.

    PubMed

    Batterman, Sarah A; Hedin, Lars O; van Breugel, Michiel; Ransijn, Johannes; Craven, Dylan J; Hall, Jefferson S

    2013-10-10

    Forests contribute a significant portion of the land carbon sink, but their ability to sequester CO2 may be constrained by nitrogen, a major plant-limiting nutrient. Many tropical forests possess tree species capable of fixing atmospheric dinitrogen (N2), but it is unclear whether this functional group can supply the nitrogen needed as forests recover from disturbance or previous land use, or expand in response to rising CO2 (refs 6, 8). Here we identify a powerful feedback mechanism in which N2 fixation can overcome ecosystem-scale deficiencies in nitrogen that emerge during periods of rapid biomass accumulation in tropical forests. Over a 300-year chronosequence in Panama, N2-fixing tree species accumulated carbon up to nine times faster per individual than their non-fixing neighbours (greatest difference in youngest forests), and showed species-specific differences in the amount and timing of fixation. As a result of fast growth and high fixation, fixers provided a large fraction of the nitrogen needed to support net forest growth (50,000 kg carbon per hectare) in the first 12 years. A key element of ecosystem functional diversity was ensured by the presence of different N2-fixing tree species across the entire forest age sequence. These findings show that symbiotic N2 fixation can have a central role in nitrogen cycling during tropical forest stand development, with potentially important implications for the ability of tropical forests to sequester CO2. PMID:24037375

  12. Postmortem MRI of Human Brain Hemispheres: T2 Relaxation Times during Formaldehyde Fixation

    PubMed Central

    Dawe, Robert J.; Bennett, David A.; Schneider, Julie A.; Vasireddi, Sunil K.; Arfanakis, Konstantinos

    2009-01-01

    Unlike in vivo imaging, postmortem MRI allows for invasive examination of the tissue specimen immediately following the MR scan. However, natural tissue decomposition and chemical fixation cause the postmortem tissue’s MRI properties to be different from those found in vivo. Moreover, these properties change as postmortem fixation time elapses. The goal of this study was to characterize the T2 relaxation changes that occur over time in cadaveric human brain hemispheres during fixation. Five hemispheres immersed in formaldehyde solution were scanned on a weekly basis for three months postmortem, and once again at six months postmortem. The T2 relaxation times were measured throughout the hemispheres. Over time, T2 values near the edges of the hemispheres decreased rapidly after death, while T2 values of deep tissue decreased more slowly. This difference is likely due to the relatively large distance from the hemisphere surface, and other barriers limiting diffusion of formaldehyde molecules to deep tissues. In addition, T2 values in deep tissue did not continuously decay to a plateau, but instead reached a minimum and then increased to a plateau. This final increase may be due to the effects of prolonged tissue decomposition, a hypothesis that is supported by numerical simulations of the fixation process. PMID:19189294

  13. Key role of symbiotic dinitrogen fixation in tropical forest secondary succession

    NASA Astrophysics Data System (ADS)

    Batterman, Sarah A.; Hedin, Lars O.; van Breugel, Michiel; Ransijn, Johannes; Craven, Dylan J.; Hall, Jefferson S.

    2013-10-01

    Forests contribute a significant portion of the land carbon sink, but their ability to sequester CO2 may be constrained by nitrogen, a major plant-limiting nutrient. Many tropical forests possess tree species capable of fixing atmospheric dinitrogen (N2), but it is unclear whether this functional group can supply the nitrogen needed as forests recover from disturbance or previous land use, or expand in response to rising CO2 (refs 6, 8). Here we identify a powerful feedback mechanism in which N2 fixation can overcome ecosystem-scale deficiencies in nitrogen that emerge during periods of rapid biomass accumulation in tropical forests. Over a 300-year chronosequence in Panama, N2-fixing tree species accumulated carbon up to nine times faster per individual than their non-fixing neighbours (greatest difference in youngest forests), and showed species-specific differences in the amount and timing of fixation. As a result of fast growth and high fixation, fixers provided a large fraction of the nitrogen needed to support net forest growth (50,000kg carbon per hectare) in the first 12years. A key element of ecosystem functional diversity was ensured by the presence of different N2-fixing tree species across the entire forest age sequence. These findings show that symbiotic N2 fixation can have a central role in nitrogen cycling during tropical forest stand development, with potentially important implications for the ability of tropical forests to sequester CO2.

  14. Vascular complications after the treatment with Ilizarov external fixators.

    PubMed

    Polak, W G; Pawlowski, S; Skora, J; Morasiewicz, L; Janczak, D; Oleszkiewicz, M; Szyber, P

    2001-05-01

    Iatrogenic vascular injuries from external fixation in orthopaedics and traumatology are frequent. Three cases of vascular injuries after the treatment with Ilizarov external fixators were treated at our institution. These include two cases of pseudoaneurysms and one case of acute ischaemia of the lower limb. Two patients became symptomatic only after removal of the fixator. In all cases, the diagnosis was made by color flow duplex sonography. All vascular injuries needed surgical repair. PMID:11417287

  15. Genetic regulation of nitrogen fixation in rhizobia.

    PubMed Central

    Fischer, H M

    1994-01-01

    This review presents a comparison between the complex genetic regulatory networks that control nitrogen fixation in three representative rhizobial species, Rhizobium meliloti, Bradyrhizobium japonicum, and Azorhizobium caulinodans. Transcription of nitrogen fixation genes (nif and fix genes) in these bacteria is induced primarily by low-oxygen conditions. Low-oxygen sensing and transmission of this signal to the level of nif and fix gene expression involve at least five regulatory proteins, FixL, FixJ, FixK, NifA, and RpoN (sigma 54). The characteristic features of these proteins and their functions within species-specific regulatory pathways are described. Oxygen interferes with the activities of two transcriptional activators, FixJ and NifA. FixJ activity is modulated via phosphorylation-dephosphorylation by the cognate sensor hemoprotein FixL. In addition to the oxygen responsiveness of the NifA protein, synthesis of NifA is oxygen regulated at the level of transcription. This type of control includes FixLJ in R. meliloti and FixLJ-FixK in A. caulinodans or is brought about by autoregulation in B. japonicum. NifA, in concert with sigma 54 RNA polymerase, activates transcription from -24/-12-type promoters associated with nif and fix genes and additional genes that are not directly involved in nitrogen fixation. The FixK proteins constitute a subgroup of the Crp-Fnr family of bacterial regulators. Although the involvement of FixLJ and FixK in nifA regulation is remarkably different in the three rhizobial species discussed here, they constitute a regulatory cascade that uniformly controls the expression of genes (fixNOQP) encoding a distinct cytochrome oxidase complex probably required for bacterial respiration under low-oxygen conditions. In B. japonicum, the FixLJ-FixK cascade also controls genes for nitrate respiration and for one of two sigma 54 proteins. Images PMID:7968919

  16. Role of soft tissues in metacarpal fracture fixation.

    PubMed

    Ouellette, Elizabeth Anne; Dennis, Jay J; Milne, Edward L; Latta, Loren L; Makowski, Anna-Lena

    2003-07-01

    The contribution of soft tissues in stabilizing fracture fixation in metacarpals is appreciated clinically, but no quantitative biomechanical study of their role has been done. All previous studies of fracture fixation in vitro have been done on metacarpals denuded of soft tissues. To quantify the role of soft tissues in metacarpal fracture fixation, the biomechanical effectiveness of four fixation devices was examined in human cadaver metacarpals with and without soft tissues. Values were compared for three nonrigid methods (expandable intramedullary fixation devices, crossed Kirschner wires, and single half-pin frames) and one rigid method (dorsal plates) in 45 disarticulated metacarpals stripped of soft tissues (denuded) and in 46 metacarpals in whole hands with all soft tissues remaining (intact). Mechanical testing to complete failure in three-point apex dorsal bending was done in all specimens. Ultimate moment (strength) of each of the four fixation methods was significantly greater in intact specimens than in denuded specimens. Crossed Kirschner wires were most stable in intact specimens, and dorsal plates were more stable in denuded specimens. The results show that soft tissues contribute to the strength of fracture fixation. Clinically, surgeons may be able to use a less invasive fixation method than plating without compromising the strength of metacarpal fixation in patients whose soft tissues are not severely disrupted and the fracture configuration allows. Plating may offer optimum stability in patients whose soft tissues are damaged severely and provide less strengthening of the fracture construct. PMID:12838068

  17. Impact of Infection on Fracture Fixation.

    PubMed

    Willey, Michael; Karam, Matthew

    2016-04-01

    Surgical site infection can be a devastating complication that results in significant morbidity in patients who undergo operative fixation of fractures. Reducing the rate of infection and wound complications in high-risk trauma patients by giving early effective antibiotics, improving soft tissue management, and using antiseptic techniques is a common topic of discussion. Despite heightened awareness, there has not been a significant reduction in surgical site infection over the past 40 years. Patients should be treated aggressively to eliminate or suppress the infection, heal the fracture if there is a nonunion, and maintain the function of the patient. PMID:26772944

  18. Assessment of carbon fibre composite fracture fixation plate using finite element analysis.

    PubMed

    Saidpour, Seyed H

    2006-07-01

    In the internal fixation of fractured bone by means of bone-plates fastened to the bone on its tensile surface, an on-going concern has been the excessive stress shielding of the bone by the excessively-stiff stainless-steel plate. The compressive stress shielding at the fracture-interface immediately after fracture-fixation delays callus formation and bone healing. Likewise, the tensile stress shielding in the layer of bone underneath the plate can cause osteoporosis and decrease in tensile strength of this layer. In this study a novel forearm internal fracture fixation plate made from short carbon fibre reinforced plastic (CFRP) was used in an attempt to address the problem. Accordingly, it has been possible to analyse the stress distribution in the composite plates using finite-element modelling. A three-dimensional, quarter-symmetric finite element model was generated for the plate system. The stress state in the underlying bone was examined for several loading conditions. Based on the analytical results the composite plate system is likely to reduce stress-shielding effects at the fracture site when subjected to bending and torsional loads. The design of the plate was further optimised by reducing the width around the innermost holes. PMID:16732432

  19. Anaerobic CO2 fixation by the acetogenic bacterium Moorella thermoacetica

    SciTech Connect

    Hu, P; Rismani-Yazdi, H; Stephanopoulos, G

    2013-05-16

    Anaerobic bacteria such as Moorella thermoacetica have the capacity of fixing carbon dioxide with carbon monoxide and hydrogen for the production of ethanol, acetic acid, and other useful chemicals. In this study, we evaluated the fixation of CO2 for the production of acetic acid, as a product in its own right but also as precursor for lipid synthesis by oleaginous organisms. We achieved maximum cell optical density of 11.3, acetic acid titer of 31 g/L, and productivity of 0.55 g/L-h at CO mass-transfer rate of 83 mM/h. We also showed electron availability by CO mass transfer limited the process at CO mass transfer rates lower than 30 mM/h. Further enhancement of mass-transfer rate removed such limitations in favor of biological kinetics as main limitation. This work underlines the potential of microbial processes for converting syngas to fuel and chemical products in processes suitable for distributed feedstock utilization. (c) 2013 American Institute of Chemical Engineers AIChE J, 59: 3176-3183, 2013

  20. TREATMENT OF POST-TRAUMATIC HUMERAL FRACTURES AND COMPLICATIONS USING THE OSTEOLINE® EXTERNAL FIXATOR: A TREATMENT OPTION

    PubMed Central

    de Azevedo, Marcos Coelho; de Azevedo, Gualter Maldonado; Hayashi, Alexandre Yoshio; Dourado Nascimento, Paulo Emilio

    2015-01-01

    To evaluate the results obtained from treatment of humeral shaft fractures and their complications using the Osteoline® uniplanar external fixator. Methods: The radiographic and functional results from 78 patients with humeral shaft fractures treated using the uniplanar external fixation technique were retrospectively assessed. The patients' ages ranged from 23 to 71 years, with a mean of 47 years. Male patients predominated (79%). Out of the 78 patients, 45 presented open fractures, 14 presented pseudarthrosis and six presented synthesis failure. There were no losses during the follow-up and all the patients were discharged after fracture consolidation and functional recovery. The results were evaluated based on the studies by Catagni, as good, fair or poor. Results: Fracture consolidation was observed in 98% of the cases treated with uniplanar external fixation. Only one pseudarthrosis case required conversion to rigid internal fixation and autologous bone grafting. At the end of the treatment, all the patients were discharged with consolidated fractures, without pain, and good limb function. Conclusion: The external fixation described in this paper was shown to be an efficient and safe method for treating humeral shaft fractures and their complications. It preserved the local biological status and enabled passive and active movement immediately after surgery. PMID:27027026

  1. Periprosthetic femoral fractures around well fixed implants: a simple method of fixation using LC-DCP with trochanteric purchase.

    PubMed

    Sen, Ramesh; Prasad, Prabhudev; Kumar, Senthil; Nagi, Onkarnath

    2007-04-01

    Periprosthetic fractures of the femur are among the most serious complications in hip surgery. Various classifications have been suggested. At present the Vancouver classification system probably comes closest to the ideal. Most authors recommend internal fixation of the fractures in well-fixed implants (Vancouver type B1). However as the fixation to the proximal fragment has always been a problem, many types of fixation devices have been used. This retrospective study was done to evaluate the efficacy of an LC-DCP with trochanteric purchase, in the fixation of Vancouver type B1 periprosthetic femoral fractures. Our study included 12 patients, 7 male and 5 female with a mean age of 73 years (range: 57 to 91). One patient died due to complications not related to surgery and in another patient the plate was found broken with a loose implant, which was revised. All cases were primary arthroplasties. A long broad LC-DCP was used for the fixation. Purchase in the proximal fragment was obtained with screws in the greater trochanter. Ten fractures united in an average period of 7 months. The mean duration of follow-up was 6.5 years. The final results were evaluated using the Harris hip score. The mean Harris hip score was 85 with a range of 75 to 94. PMID:17515232

  2. Clinical results of resection arthrodesis by triangular external fixation for posttraumatic arthrosis of the ankle joint in 89 cases

    PubMed Central

    2009-01-01

    The methods for ankle arthrodesis differ significantly, probably a sign that no method is clearly superior to others. In the last ten years there is a clear favour toward internal fixation. We retrospectively evaluate the technique and evaluate the clinical long term results of external fixation in a triangular frame. Patients and Methods From 1994 to 2001 a consecutive series of 95 patients with end stage arthritis of the ankle joint were treated. Retrospectively the case notes were evaluated regarding trauma history, medical complaints, further injuries and illnesses, walking and pain status and occupational issues and the clinical examination before arthrodesis. Mean age at the index procedure was 45.4 years (18-82), 67 patients were male (70.5%). Via a bilateral approach the malleoli and the joint surfaces were resected. An AO fixator was applied with two Steinmann-nails inserted with approximately 8 cm distance in the distal tibia, one in the neck of the talus and one in the dorsal calcaneus. The fixator was removed after approximately 12 weeks. Follow up examination at mean 4.4 years included a standardised questionnaire and a clinical examination including the criteria of the AOFAS-Score and radiographs. Results: Due to different complications, 8 (8.9%) further surgical procedures were necessary including 1 below knee amputation. In 4 patients a non-union of the ankle arthrodesis developed (4.5%). The mean AOFAS score improved from 20.8 to 69.3 points. Conclusion Non-union rates and clinical results of arthrodesis by triangular external fixation of the ankle joint do not differ to internal fixation methods. The complication rate and the reduced patient comfort reserve this method mainly for infected arthritis and complicated soft tissue situations. PMID:19258207

  3. Nitrogen Fixation and Hydrogen Metabolism in Cyanobacteria

    PubMed Central

    Bothe, Hermann; Schmitz, Oliver; Yates, M. Geoffrey; Newton, William E.

    2010-01-01

    Summary: This review summarizes recent aspects of (di)nitrogen fixation and (di)hydrogen metabolism, with emphasis on cyanobacteria. These organisms possess several types of the enzyme complexes catalyzing N2 fixation and/or H2 formation or oxidation, namely, two Mo nitrogenases, a V nitrogenase, and two hydrogenases. The two cyanobacterial Ni hydrogenases are differentiated as either uptake or bidirectional hydrogenases. The different forms of both the nitrogenases and hydrogenases are encoded by different sets of genes, and their organization on the chromosome can vary from one cyanobacterium to another. Factors regulating the expression of these genes are emerging from recent studies. New ideas on the potential physiological and ecological roles of nitrogenases and hydrogenases are presented. There is a renewed interest in exploiting cyanobacteria in solar energy conversion programs to generate H2 as a source of combustible energy. To enhance the rates of H2 production, the emphasis perhaps needs not to be on more efficient hydrogenases and nitrogenases or on the transfer of foreign enzymes into cyanobacteria. A likely better strategy is to exploit the use of radiant solar energy by the photosynthetic electron transport system to enhance the rates of H2 formation and so improve the chances of utilizing cyanobacteria as a source for the generation of clean energy. PMID:21119016

  4. Fixation of basicervical and related fractures

    PubMed Central

    2009-01-01

    We prospectively studied 42 patients in order to identify a group of proximal femoral fractures having liability for axial and rotational instability, and to present results of their fixation using the dynamic hip screw (DHS) with derotation screw (DRS). At 12 months postoperatively, patients were functionally evaluated and the radiological outcome was analysed. All fractures united within an average period of 11.5 weeks. The mean sliding distance was 5.5 mm and mean shortening of the limbs was 2 mm. According to the criteria of Kyle et al. (J Bone Joint Surg [Am] 61-A:216–221), 39 patients obtained excellent results, two good and one fair. We conclude that the AO types B2.1, A1.1, A2.1, A2.2 and A2.3 have a common instability denominator and therefore should be treated alike. The sliding component of the DHS allows solid fixation of the two major fragments in two planes and the DRS in the third plane. PMID:19475407

  5. Nitrogen fixation: key genetic regulatory mechanisms.

    PubMed

    Martinez-Argudo, I; Little, R; Shearer, N; Johnson, P; Dixon, R

    2005-02-01

    The necessity to respond to the level of fixed nitrogen and external oxygen concentrations and to provide sufficient energy for nitrogen fixation imposes common regulatory principles amongst diazotrophs. The NifL-NifA system in Azotobacter vinelandii integrates the signals of redox, fixed-nitrogen and carbon status to regulate nif transcription. Multidomain signalling interactions between NifL and NifA are modulated by redox changes, ligand binding and interaction with the signal-transduction protein GlnK. Under adverse redox conditions (excess oxygen) or when fixed nitrogen is in excess, NifL forms a complex with NifA in which transcriptional activation is prevented. Oxidized NifL forms a binary complex with NifA to inhibit NifA activity. When fixed nitrogen is in excess, the non-covalently modified form of GlnK interacts with NifL to promote the formation of a GlnK-NifL-NifA ternary complex. When the cell re-encounters favourable conditions for nitrogen fixation, it is necessary to deactivate the signals to ensure that the NifL-NifA complex is dissociated so that NifA is free to activate transcription. This is achieved through interactions with 2-oxoglutarate, a key metabolic signal of the carbon status, which binds to the N-terminal GAF (cGMP-specific and stimulated phosphodiesterases, Anabaena adenylate cyclases and Escherichia coli FhlA) domain of NifA. PMID:15667291

  6. Hiatus Hernia Repair with Bilateral Oesophageal Fixation

    PubMed Central

    Martin, David

    2015-01-01

    Background. Despite advances in surgical repair of hiatus hernias, there remains a high radiological recurrence rate. We performed a novel technique incorporating bilateral oesophageal fixation and evaluated outcomes, principally symptom improvement and hernia recurrence. Methods. A retrospective study was performed on a prospective database of patients undergoing hiatus hernia repair with bilateral oesophageal fixation. Retrospective and prospective quality of life (QOL), PPI usage, and patient satisfaction data were obtained. Hernia recurrence was assessed by either barium swallow or gastroscopy. Results. 87 patients were identified in the database with a minimum of 3 months followup. There were significant improvements in QOL scores including GERD HRQL (29.13 to 4.38, P < 0.01), Visick (3 to 1), and RSI (17.45 to 5, P < 0.01). PPI usage decreased from a median of daily to none, and there was high patient satisfaction (94%). 57 patients were assessed for recurrence with either gastroscopy or barium swallow, and one patient had evidence of recurrence on barium swallow at 45 months postoperatively. There was an 8% complication rate and no mortality or oesophageal perforation. Conclusions. This study demonstrates that our technique is both safe and effective in symptom control, and our recurrence investigations demonstrate at least short term durability. PMID:26065030

  7. Fast fixation with a generic network structure

    NASA Astrophysics Data System (ADS)

    Baxter, Gareth J.; Blythe, Richard A.; McKane, Alan J.

    2012-09-01

    We investigate the dynamics of a broad class of stochastic copying processes on a network that includes examples from population genetics (spatially structured Wright-Fisher models), ecology (Hubbell-type models), linguistics (the utterance selection model), and opinion dynamics (the voter model) as special cases. These models all have absorbing states of fixation where all the nodes are in the same state. Earlier studies of these models showed that the mean time when this occurs can be made to grow as different powers of the network size by varying the degree distribution of the network. Here we demonstrate that this effect can also arise if one varies the asymmetry of the copying dynamics while holding the degree distribution constant. In particular, we show that the mean time to fixation can be accelerated even on homogeneous networks when certain nodes are very much more likely to be copied from than copied to. We further show that there is a complex interplay between degree distribution and asymmetry when they may covary, and that the results are robust to correlations in the network or the initial condition.

  8. Do Low 15N Values in Paleozoic Epeiric Basins Indicate High Rates of N Fixation?

    NASA Astrophysics Data System (ADS)

    Tuite, M. L.; Macko, S. A.

    2011-12-01

    As a consequence of the high energetic requirements of dinitrogen (N2) fixation, organic N produced by diazotrophic microorganisms typically exhibits δ15N values similar to atmospheric N2 (approximately 0%). Because the δ15N of organic-rich Paleozoic epeiric basin sediments often has values in the vicinity of 0%, it is frequently asserted that N2 fixation was the primary source of new reactive N for productivity. There are two broad reasons why recourse to widespread and intensive N fixation as the primary source of the organic N is problematic. First, there are substantial physiological and ecological constraints on marine N fixation that limit its extent in modern oceans primarily to open ocean basins. Second, preservation of an unaltered isotopic signature of diazotrophy in underlying sediments is not a likely outcome of oxic and anoxic diagenetic alteration and repeated cycles of mineralization and assimilation. Constraining the sources of reactive N for primary productivity is critical to understanding the N cycle in Paleozoic epeiric seas. In this study we report δ15N values from high organic matter Middle Ordovician through Late Devonian dysoxic and euxinic basinal sediments. We propose a nitrogen isotope mass balance model that incorporates the microbial ecology of a stratified water column and the biochemical stoichiometry of primary production and organic matter diagenesis. Results from the model support our contention that high rates of N fixation over extended time periods were not the cause of depleted nitrogen isotope values in organic-rich Paleozoic basinal sediments. Rather, the depleted values were a consequence of a diminished role for nitrification and subsequent N loss via denitrification and anammox, and the preferential preservation of a substantially 15N-depleted chlorophyll-influenced lipid fraction. The model may be applicable to earlier and later geological periods where high organic matter sediments feature depleted δ15N values.

  9. Molecular Ecological and Stable Isotopic Studies of Nitrogen Fixation in Modern Microbial Mats

    NASA Technical Reports Server (NTRS)

    Bebout, B. M.; Crumbliss, L. L.; DesMarais, D. J.; Hogan, M. E.; Omoregie, E.; Turk, K. A.; Zehr, J. P.

    2003-01-01

    Nitrogen is usually the element limiting biological productivity in the marine environment. Microbial mats, laminated microbial communities analogous to some of the oldest forms of life on Earth, are often the sites of high rates of N fixation (the energetically expensive conversion of atmospheric dinitrogen into a biologically useful form). The N fixing enzyme nitrogenase is generally considered to be of ancient origin, and is widely distributed throughout the Bacterial and Archaeal domains of life, indicating an important role for this process over evolutionary time. The stable isotopic signature of N fixation is purportedly recognizable in organic matter (ancient kerogens as well as present-day microbial mats) as a delta (15)N(sub organic) near zero. We studied two microbial mats exhibiting different rates of N fixation in order to better understand the impact of N fixation on the delta (15)N (sub organic) of the mats, as well as what organisms are important in this process. Mats dominated by the cyanobacterium Microcoleus chthonoplastes grow in permanently submerged hypersaline salterns, and exhibit low rates of N fixation, whereas mats dominated by the cyanobacterium Lyngbya spp grow in an intertidal area, and exhibit rates of N fixation an order of magnitude higher. To examine successional stages in mat growth, both developing and established mats at each location were sampled. PCR and RT-PCR based approaches were used to identify, respectively, the organisms containing nifH (one of the genes that encode nitrogenase) as well as those expressing nifH in these mats. Both mats exhibited a distinct diel cycle of N fixation, with highest rates occurring at night. The delta (15)N(sub organic) of the subtidal Microcoleus mats is near zero whereas the delta (15)N(sub organic) is slightly more positive (+ 2-3%), in the intertidal Lyngbya mats, an interesting difference in view of the fact that overall rates of activity in the intertidal mats are much higher that those

  10. Global changes in the transcript and metabolic profiles during symbiotic nitrogen fixation in phosphorus-stressed common bean plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) deficiency is widespread in regions where the common bean (Phaseolus vulgaris L.), the most important legume for human consumption, is produced and is perhaps the factor that most limits nitrogen (N) fixation. Global gene expression and metabolome approaches were used to investigate t...

  11. Nitrogen fixation in boreal peatlands: the effects of increased N deposition on N2-fixation

    NASA Astrophysics Data System (ADS)

    Popma, J. M.; Wieder, R.; Lamers, L.; Vile, M. A.

    2013-12-01

    Boreal peatlands are of great importance to global carbon and nitrogen cycling. While covering only 3-4 % of the terrestrial surface, they account for 25-30 % of the world's soil C and 9-15 % of the world's soil N. In Western Canada atmospheric dry deposition rates are extremely low: approximately 1 kg N ha-1 yr-1. Though these systems have been functioning as net sinks over the past 11,000 years, natural and anthropogenic disturbances might compromise the historical balance of C and N. Biological N2-fixation has recently been shown to represent a very significant input of N into these systems, contributing to 62% of total N in Western Canada. Interactions between N deposition and biological N2-fixation are as yet, unknown, but the impact of elevated deposition of N-compounds from increased industrial expansion of oil sands mining to peatlands, is concerning. Given that nitrogenase, the enzyme responsible for catalyzing N2-fixation, is energetically costly when active, enhanced inputs of atmospheric N deposition could be a major determinant for enzyme activity and rates of biological N input to these bogs. Understanding interactions between N deposition and N2 fixation in boreal peatlands can aid in predicting the consequences of increased N deposition and setting critical loads. We conducted a field-fertilization experiment in a poor fen in Alberta, Canada, to determine the effects of enhanced N deposition on a dominant fen species Sphagnum angustifolium. The experiment consisted of seven N treatments: Control, 0, 5, 10, 15, 20 and 25 kg N ha-1 y1, n=3. N2-fixation was measured during summer 2012 and 2013 using the acetylene reduction assay (ARA). ARA rates were converted to rates of N2-fixation by calibrating ARA with paired 15N2-incubations. In both 2012 and 2013, with increasing N deposition from 0 kg N ha-1 yr-1 to 25 kg N ha-1 yr-1, rates of N2 fixation decreased, with highest rates in the 0 kg N ha-1 yr-1 treatment mosses (54.2 × 1.40; 48.58 × 7.12 kg N ha

  12. 21 CFR 888.3020 - Intramedullary fixation rod.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intramedullary fixation rod. 888.3020 Section 888.3020 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... (bone marrow) canal of long bones for the fixation of fractures. (b) Classification. Class II....

  13. CRISP: A Computational Model of Fixation Durations in Scene Viewing

    ERIC Educational Resources Information Center

    Nuthmann, Antje; Smith, Tim J.; Engbert, Ralf; Henderson, John M.

    2010-01-01

    Eye-movement control during scene viewing can be represented as a series of individual decisions about where and when to move the eyes. While substantial behavioral and computational research has been devoted to investigating the placement of fixations in scenes, relatively little is known about the mechanisms that control fixation durations.…

  14. FIXATION OF FISH TISSUES. IN: THE LABORATORY FISH.

    EPA Science Inventory

    This chapter deals with the fixation of fish tissues and whole fish. Traditionally, fixation has been applied to animal tissues mainly for histological or pathological studies. Development of new molecular and immunologic tools now allows tissue and cellular localization of nucle...

  15. Sacroiliac screw fixation: A mini review of surgical technique

    PubMed Central

    Alvis-Miranda, Hernando Raphael; Farid-Escorcia, Hector; Alcalá-Cerra, Gabriel; Castellar-Leones, Sandra Milena; Moscote-Salazar, Luis Rafael

    2014-01-01

    The sacral percutaneous fixation has many advantages but can be associated with a significant exposure to X-ray radiation. Currently, sacroiliac screw fixation represents the only minimally invasive technique to stabilize the posterior pelvic ring. It is a technique that should be used by experienced surgeons. We present a practical review of important aspects of this technique. PMID:25336831

  16. 21 CFR 878.3250 - External facial fracture fixation appliance.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false External facial fracture fixation appliance. 878.3250 Section 878.3250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... External facial fracture fixation appliance. (a) Identification. An external facial fracture...

  17. 21 CFR 878.3250 - External facial fracture fixation appliance.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false External facial fracture fixation appliance. 878.3250 Section 878.3250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... External facial fracture fixation appliance. (a) Identification. An external facial fracture...

  18. 21 CFR 878.3250 - External facial fracture fixation appliance.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false External facial fracture fixation appliance. 878.3250 Section 878.3250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... External facial fracture fixation appliance. (a) Identification. An external facial fracture...

  19. Cultivar effects on nitrogen fixation in peas and lentils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing nitrogen fixation in legume crops could increase cropping productivity and reduce nitrogen fertilizer use. Studies have found that crop genotype, rhizobial strain, and occasionally genotype-specific interactions affect N fixation, but this knowledge has not yet been used to evaluate or br...

  20. Monitoring in vivo load transmission through an external fixator.

    PubMed

    Grasa, J; Gómez-Benito, M J; González-Torres, L A; Asiaín, D; Quero, F; García-Aznar, J M

    2010-03-01

    This work presents a portable non-invasive external fixator to assess and monitor fracture healing in real time. To evaluate the potential of this fixator, a transverse osteotomy was performed in the tibia of six adult sheep (mean age 3+/-0.5 years and weight 63+/-5 kg). The fractures were stabilized by a specially designed unilateral external fixator, which was instrumented by means of a set of strain gauges. Strains in the external surface of the fixator were monitored during all the healing process. A wireless, remote monitoring of the implant was developed through a specially designed external telemetric device. The strain gauges were arranged in two different half-bridge Wheatstone configurations, allowing easy post-processing of the signal. Thus, bending loads were measured in two planes of the external fixator acting as a load cell. The load through the fixator was evaluated for the gait cycle during all the healing process. Full weight bearing of the injured leg was observed from the beginning. The load transmission mechanism in the fixator was quite similar in all operated tibias and radiographic images showed a successful healing in all animals. Although the fixator has only been tested in an animal model, after further testing this system may have clinical potential. PMID:20052616

  1. 21 CFR 872.4880 - Intraosseous fixation screw or wire.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intraosseous fixation screw or wire. 872.4880 Section 872.4880 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES.... (a) Identification. An intraosseous fixation screw or wire is a metal device intended to be...

  2. Humor Preference as a Function of Preoedipal Fixation.

    ERIC Educational Resources Information Center

    Juni, Samuel

    1982-01-01

    Psychoanalytic theory predicts that humor preference is a derivative of unresolved childhood conflicts. Analyzed students' (N=104) Rorschach protocols to yield measures of preoedipal fixation. Students ranked jokes from most to least funny. Results showed that the ranking of jokes was a function of the fixation measures for women only. (Author/RC)

  3. Core Concepts: Orthopedic Intern Curriculum Boot Camp.

    PubMed

    Seeley, Mark A; Kazarian, Erick; King, Brandon; Biermann, Janet S; Carpenter, James E; Caird, Michelle S; Irwin, Todd A

    2016-01-01

    Orthopedic surgical interns must gain a broad array of clinical skills in a short time. However, recent changes in health care have limited resident-patient exposures. With the reported success of simulation training in the surgical literature, the American Board of Orthopaedic Surgery (ABOS) and Residency Review Committee for Orthopaedic Surgery have required that surgical simulation training be a component of the intern curricula in orthopedic surgical residencies. This study examined the short-term effectiveness of an orthopedic "intern boot camp" covering 7 of 17 simulation training concept modules published by the ABOS. Eight orthopedic post-graduate year 1 (PGY-1) residents (study group) completed a structured 3-month curriculum and were compared with 7 post-graduate year 2 (PGY-2) residents (comparison group) who had just completed their orthopedic surgical internship. Seven core skills were assessed using both task-specific and global rating scales. The PGY-1 residents demonstrated a statistically significant improvement in all 7 modules with respect to their task-specific pre-test scores: sterile technique (P=.001), wound closure (P<.001), knot tying (P=.017), casting and splinting (P<.001), arthrocentesis (P=.01), basics of internal fixation (P<.001), and compartment syndrome evaluation (P=.004). After the camp, PGY-1 and -2 scores in task-specific measures were not significantly different. A 3-month simulation-based boot camp instituted early in orthopedic internship elevated a variety of clinical skills to levels exhibited by PGY-2 residents. PMID:26730688

  4. Unicortical versus bicortical locked plate fixation in midshaft clavicle fractures.

    PubMed

    Bravman, Jonathan T; Taylor, Michal L; Baldini, Todd; Vidal, Armando F

    2015-05-01

    Higher rates of poor outcomes in displaced midshaft clavicle fractures treated nonoperatively have recently been reported. Along with expanding indications for operative fixation and increasing application of locked plate constructs, it is unknown whether complications related to bicortical penetration of the clavicle can be avoided using unicortical fixation. The purpose of this study is to compare the biomechanical properties of unicortical and bicortical fixation in precontoured vs manually contoured locking clavicle plates. Forty-eight Sawbone composite human clavicle specimens (item #3408; Pacific Research Laboratories, Vashon, Washington) with a midshaft clavicle osteotomy were reduced and plated in 8 specimens each using a bicortical and unicortical fixation for each of 3 locked plate constructs (3.5-mm LCP Reconstruction Plate; 3.5-mm LCP Superior Clavicle Plate; 3.5-mm LCP Superior Anterior Clavicle Plate; Synthes, Inc, West Chester, Pennsylvania). Specimens were tested for stiffness in axial torsion and cantilever bending and then loaded to failure in 3-point bending. Data were analyzed using 2-way analysis of variance and Tukey's test (P<.05). No significant differences were found between unicortical and bicortical fixation in failure load, cantilever bending, and cross body stiffness. Bicortical fixation was significantly stiffer than unicortical fixation in torsion only for the same plates. Significant differences also existed between plates in torsion. Unicortical locked plate fixation may be a reasonable option in the treatment of displaced midshaft clavicle fracture fixation to avoid complications associated with posteroinferior hardware penetration following clavicle fracture fixation based on the biomechanical performance of these constructs. However, it remains unclear whether these differences will be clinically significant. PMID:25970369

  5. Uncertainties of Nitrogen Fixation in a Dynamic Global Vegetation Model

    NASA Astrophysics Data System (ADS)

    Steinkamp, Joerg; Werner, Christian; Weber, Bettina; Hickler, Thomas

    2015-04-01

    Nitrogen is an essential nutrient for life on earth. However, most of it is in the form of dinitrogen (N2) unutilizable to life and only few organisms are able to break the triple bond, fix the nitrogen and thus make it available for cycling in the biosphere through "fixation". In most state-of-the-art dynamic global vegetation models (DGVMs) including a nitrogen cycle, N fixation is simulated by the Cleveland et al. (1999) algorithm (O-CN, LPJ-GUESS, CLM), that correlates annual N fixation to evapotranspiration rates or net primary production. Nevertheless, this algorithm has two major uncertainties, which are investigated by us: 1. The algorithm is based on annual fixation rates that are then applied uniformly throughout the year. However, in nature nitrogen fixation is an expensive process, which occurs only under favorable conditions. Here we compare the annual fixation values evenly distributed over the year with daily-derived fixation values based on a modified version of the Cleveland algorithm. We postulate that in higher latitudinal regions with seasonal climate as well as in regions with a distinct dry/wet season, modeled growth is enhanced by daily derived values compared to evenly distributed values, whereas in tropical regions hardly any difference will be visible. 2. One distinguishes between symbiotic and unsymbiotic nitrogen fixation, where the first one is associated with higher plants as symbionts supplying the fixers with carbohydrates, whereas the second, unsymbiotic is performed by so-called cryptogamic covers (CC). We found that the fixation by CC is underrepresented by the Cleveland algorithm, and a correction thus leads to enhanced growth in forested regions of higher latitudes that feature substantial CC fractions. Overall, the improvements of the algorithm proposed by us are expected to better reflect the reality of nitrogen fixation and cause an increased growth of vegetation, especially in higher northern latitudes.

  6. Neural Correlates of Fixation Duration during Real-world Scene Viewing: Evidence from Fixation-related (FIRE) fMRI.

    PubMed

    Henderson, John M; Choi, Wonil

    2015-06-01

    During active scene perception, our eyes move from one location to another via saccadic eye movements, with the eyes fixating objects and scene elements for varying amounts of time. Much of the variability in fixation duration is accounted for by attentional, perceptual, and cognitive processes associated with scene analysis and comprehension. For this reason, current theories of active scene viewing attempt to account for the influence of attention and cognition on fixation duration. Yet almost nothing is known about the neurocognitive systems associated with variation in fixation duration during scene viewing. We addressed this topic using fixation-related fMRI, which involves coregistering high-resolution eye tracking and magnetic resonance scanning to conduct event-related fMRI analysis based on characteristics of eye movements. We observed that activation in visual and prefrontal executive control areas was positively correlated with fixation duration, whereas activation in ventral areas associated with scene encoding and medial superior frontal and paracentral regions associated with changing action plans was negatively correlated with fixation duration. The results suggest that fixation duration in scene viewing is controlled by cognitive processes associated with real-time scene analysis interacting with motor planning, consistent with current computational models of active vision for scene perception. PMID:25436668

  7. Irreversibly increased nitrogen fixation in Trichodesmium experimentally adapted to elevated carbon dioxide

    PubMed Central

    Hutchins, David A.; Walworth, Nathan G.; Webb, Eric A.; Saito, Mak A.; Moran, Dawn; McIlvin, Matthew R.; Gale, Jasmine; Fu, Fei-Xue

    2015-01-01

    Nitrogen fixation rates of the globally distributed, biogeochemically important marine cyanobacterium Trichodesmium increase under high carbon dioxide (CO2) levels in short-term studies due to physiological plasticity. However, its long-term adaptive responses to ongoing anthropogenic CO2 increases are unknown. Here we show that experimental evolution under extended selection at projected future elevated CO2 levels results in irreversible, large increases in nitrogen fixation and growth rates, even after being moved back to lower present day CO2 levels for hundreds of generations. This represents an unprecedented microbial evolutionary response, as reproductive fitness increases acquired in the selection environment are maintained after returning to the ancestral environment. Constitutive rate increases are accompanied by irreversible shifts in diel nitrogen fixation patterns, and increased activity of a potentially regulatory DNA methyltransferase enzyme. High CO2-selected cell lines also exhibit increased phosphorus-limited growth rates, suggesting a potential advantage for this keystone organism in a more nutrient-limited, acidified future ocean. PMID:26327191

  8. Irreversibly increased nitrogen fixation in Trichodesmium experimentally adapted to elevated carbon dioxide

    NASA Astrophysics Data System (ADS)

    Hutchins, David A.; Walworth, Nathan G.; Webb, Eric A.; Saito, Mak A.; Moran, Dawn; McIlvin, Matthew R.; Gale, Jasmine; Fu, Fei-Xue

    2015-09-01

    Nitrogen fixation rates of the globally distributed, biogeochemically important marine cyanobacterium Trichodesmium increase under high carbon dioxide (CO2) levels in short-term studies due to physiological plasticity. However, its long-term adaptive responses to ongoing anthropogenic CO2 increases are unknown. Here we show that experimental evolution under extended selection at projected future elevated CO2 levels results in irreversible, large increases in nitrogen fixation and growth rates, even after being moved back to lower present day CO2 levels for hundreds of generations. This represents an unprecedented microbial evolutionary response, as reproductive fitness increases acquired in the selection environment are maintained after returning to the ancestral environment. Constitutive rate increases are accompanied by irreversible shifts in diel nitrogen fixation patterns, and increased activity of a potentially regulatory DNA methyltransferase enzyme. High CO2-selected cell lines also exhibit increased phosphorus-limited growth rates, suggesting a potential advantage for this keystone organism in a more nutrient-limited, acidified future ocean.

  9. Methane-Stimulated Benthic Marine Nitrogen Fixation at Deep-Sea Methane Seeps

    NASA Astrophysics Data System (ADS)

    Dekas, A. E.; Orphan, V.

    2011-12-01

    Biological nitrogen fixation (the conversion of N2 to NH3) is a critical process in the oceans, counteracting the production of N2 gas by dissimilatory bacterial metabolisms and providing a source of bioavailable nitrogen to many nitrogen-limited ecosystems. Although current measurements of N2 production and consumption in the oceans indicate that the nitrogen cycle is not balanced, recent findings on the limits of nitrogen fixation suggest that the perceived imbalance is an artifact of an incomplete assessment of marine diazotrophy. One currently poorly studied and potentially underappreciated habitat for diazotrophic organisms is the sediments of the deep-sea. In the present study we investigate the distribution and magnitude of benthic marine diazotrophy at several active deep-sea methane seeps (Mound 12, Costa Rica; Eel River Basin, CA, USA; Hydrate Ridge, OR, USA; and Monterey Canyon, CA, USA). Using 15N2 and 15NH4 sediment incubation experiments followed by single-cell (FISH-NanoSIMS) and bulk isotopic analysis (EA-IRMS), we observed total protein synthesis (15N uptake from 15NH4) and nitrogen fixation (15N update from 15N2). The highest rates of nitrogen fixation observed in the methane seep sediment incubation experiments were over an order of magnitude greater than those previously published from non-seep deep-sea sediments (Hartwig and Stanley, Deep-Sea Research, 1978, 25:411-417). However, methane seep diazotrophy appears to be highly spatially variable, with sediments exhibiting no nitrogen fixation originating only centimeters away from sediments actively incorporating 15N from 15N2. The greatest spatial variability in diazotrophy was observed with depth in the sediment, and corresponded to steep gradients in sulfate and methane. The maximum rates of nitrogen fixation were observed within the methane-sulfate transition zone, where organisms mediating the anaerobic oxidation of methane are typically in high abundance. Additionally, incubation

  10. Oxygen relations of nitrogen fixation in cyanobacteria.

    PubMed Central

    Fay, P

    1992-01-01

    The enigmatic coexistence of O2-sensitive nitrogenase and O2-evolving photosynthesis in diazotrophic cyanobacteria has fascinated researchers for over two decades. Research efforts in the past 10 years have revealed a range of O2 sensitivity of nitrogenase in different strains of cyanobacteria and a variety of adaptations for the protection of nitrogenase from damage by both atmospheric and photosynthetic sources of O2. The most complex and apparently most efficient mechanisms for the protection of nitrogenase are incorporated in the heterocysts, the N2-fixing cells of cyanobacteria. Genetic studies indicate that the controls of heterocyst development and nitrogenase synthesis are closely interrelated and that the expression of N2 fixation (nif) genes is regulated by pO2. Images PMID:1620069

  11. VAC® for external fixation of flail chest

    PubMed Central

    Winge, Rikke; Berg, Jais O.; Albret, Rikke; Krag, Christen

    2012-01-01

    A large aterior chest wall defect following tumor resection was reconstructed with a Gore-Tex® membrane and a combined musculocutaneous rectus femoris and tensor fasciae latae free flap. Subsequent paradoxical respiration impeded weaning from the ventilator. Appliance of Vacuum Assisted Closure® (VAC®) resulted in immediate chest wall stability and a decrease in the patient's need for respiratory support. Shortly thereafter, the VAC® was discontinued and the patient was discharged from the intensive care unit (ICU). This case report is the first to describe the successful use of VAC® as an adjuvant to a one-stage procedure for large thoracic wall reconstruction, allowing sufficient temporary external fixation to eliminate paradoxical respiration and plausibly shorten the stay in the ICU. No adverse effects on flap healing or haemodynamics were recorded. It is likely that external VAC® can improve thoracic stability and pulmonary function in a patient with flail chest and decrease the need for mechanical ventilation. PMID:24765464

  12. VAC® for external fixation of flail chest.

    PubMed

    Winge, Rikke; Berg, Jais O; Albret, Rikke; Krag, Christen

    2012-05-29

    A large aterior chest wall defect following tumor resection was reconstructed with a Gore-Tex® membrane and a combined musculocutaneous rectus femoris and tensor fasciae latae free flap. Subsequent paradoxical respiration impeded weaning from the ventilator. Appliance of Vacuum Assisted Closure® (VAC®) resulted in immediate chest wall stability and a decrease in the patient's need for respiratory support. Shortly thereafter, the VAC® was discontinued and the patient was discharged from the intensive care unit (ICU). This case report is the first to describe the successful use of VAC® as an adjuvant to a one-stage procedure for large thoracic wall reconstruction, allowing sufficient temporary external fixation to eliminate paradoxical respiration and plausibly shorten the stay in the ICU. No adverse effects on flap healing or haemodynamics were recorded. It is likely that external VAC® can improve thoracic stability and pulmonary function in a patient with flail chest and decrease the need for mechanical ventilation. PMID:24765464

  13. Osteochondritis Dessicans- Primary Fixation using Bioabsorbable Implants

    PubMed Central

    Galagali, Anand; Rao, Muralidhar

    2012-01-01

    Introduction: Osteochondritis dessicans (OCD) is a localized condition where a section of articular cartilage and underlying subchondral bone separate from the joint surface. It is important to diagnose unstable OCD early and fix the fragments primarily as the results of any surgical management at late presentations are guarded. Use of bioabsorbable implants for fixing OCD is recent and we report one such case in grade IV OCD. Case Report: We present a 14 year old girl who came with a history of acute pain, swelling, inability to bear weight on the right knee following a dance practice. MRI showed stage IV osteochondral fragment measuring 20x 8mm lying free. This was primarily fixed with bioabsorbable implants. 10 months follow up showed excellent clinical and functional results. Conclusion: This case highlights the advantages of early primary fixation whenever possible. By far, to our knowledge, this is the first case of successful treatment of stage IV OCD using bioabsorbable implants.

  14. Technique tip: percutaneous fixation of partial incongruous Lisfranc injuries in athletes.

    PubMed

    Bleazey, Scott T; Brigido, Stephen A; Protzman, Nicole M

    2013-06-01

    Open reduction with screw fixation is considered the standard surgical approach for injuries of the Lisfranc complex in athletes. However, multiple incisions are required, which increase the risk for postoperative complications. We present a novel percutaneous reduction and solid screw fixation technique that may be a viable option to address partial incongruous injuries of the Lisfranc complex in athletes. At our institution, no intraoperative or postoperative complications have been encountered. Screw breakage did not occur. Reduction of the second metatarsal was considered anatomic across all patients. All patients have returned to their respective sport without limitation. The percutaneous approach appears to decrease complications while the targeting-reduction guide appears to precisely reduce the injury. Consequently, outcomes have been more consistent and predictable. The authors note that this percutaneous approach is specific to partial incongruous injuries of the Lisfranc complex. When presented with more extensive injuries, the authors advocate an open approach. PMID:23631892

  15. Robust biological nitrogen fixation in a model grass-bacterial association.

    PubMed

    Pankievicz, Vânia C S; do Amaral, Fernanda P; Santos, Karina F D N; Agtuca, Beverly; Xu, Youwen; Schueller, Michael J; Arisi, Ana Carolina M; Steffens, Maria B R; de Souza, Emanuel M; Pedrosa, Fábio O; Stacey, Gary; Ferrieri, Richard A

    2015-03-01

    Nitrogen-fixing rhizobacteria can promote plant growth; however, it is controversial whether biological nitrogen fixation (BNF) from associative interaction contributes to growth promotion. The roots of Setaria viridis, a model C4 grass, were effectively colonized by bacterial inoculants resulting in a significant enhancement of growth. Nitrogen-13 tracer studies provided direct evidence for tracer uptake by the host plant and incorporation into protein. Indeed, plants showed robust growth under nitrogen-limiting conditions when inoculated with an ammonium-excreting strain of Azospirillum brasilense. (11)C-labeling experiments showed that patterns in central carbon metabolism and resource allocation exhibited by nitrogen-starved plants were largely reversed by bacterial inoculation, such that they resembled plants grown under nitrogen-sufficient conditions. Adoption of S. viridis as a model should promote research into the mechanisms of associative nitrogen fixation with the ultimate goal of greater adoption of BNF for sustainable crop production. PMID:25645593

  16. The design and performance of an experimental external fixation device with load transducers.

    PubMed

    Draper, E R; Wallace, A L; Strachan, R K; Hughes, S P; Nicol, A C; Paul, J P

    1995-12-01

    It is becoming increasingly common that fracture healing is modelled in the laboratory with an osteotomy in the diaphysis of the ovine tibia. External fixation is often used to hold the bones in these models, presenting the problem that the loads on such devices are poorly understood. To help investigate this, a unilateral device has been developed which is capable of measuring the two components of load considered to be the most important, that of axial compression and bending in the plane of the fixator. The device was found to be a rigid system and easy to apply, with the in-vivo measurements being straightforward. The estimated limits of error of the compression transducer are +37.9 N and -21.4 N and those of the bending transducer are +3.6 Nm and -4.2 Nm. Preliminary measurements showed the maximum load during normal walking to 345 N compression and 28 Nm in-plane bending. PMID:8564157

  17. Phase-contrast Hounsfield units of fixated and non-fixated soft-tissue samples<