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Sample records for established fixation techniques

  1. Medial Patellofemoral Ligament Reconstruction: Fixation Technique Biomechanics.

    PubMed

    Russo, Franco; Doan, Joshua; Chase, Derek C; Farnsworth, Christine L; Pennock, Andrew T

    2016-05-01

    Introduction The medial patellofemoral ligament (MPFL) is the primary soft-tissue stabilizer of the patella and it is often reconstructed in patients with recurrent patella instability. This biomechanical analysis evaluates the integrity of four methods of MPFL reconstruction subjected to cyclic loading using a porcine model. Methods Four techniques of MPFL reconstruction were analyzed using a 4 mm flexor tendon graft, all with two points of patellar fixation to best recreate the native MPFL anatomy. The four techniques were: (1) interference screw technique, (2) suture anchor technique, (3) converging tunnel technique, and (4) two bone tunnel technique. Maximum load, yield load, and stiffness of the graft fixation/bone complex were analyzed, and statistics were performed with SPSS and significance set at a p-value of < 0.05. Results The converging tunnel technique demonstrated the highest maximum load and yield load, significantly higher than the interference screw or suture anchor groups (p = 0.007). In addition, the converging tunnel technique demonstrated the greatest stiffness with significantly greater stiffness than the two bone tunnel techniques (p = 0.016). Conclusion The combination of strength and stiffness, the avoidance of patella implants, and the creation of a single transosseous tunnel make the converging tunnel technique a desirable technique for MPFL reconstructions. PMID:26190788

  2. 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

  3. Porcine Intestinal Mast Cells. Evaluation of Different Fixatives for Histochemical Staining Techniques Considering Tissue Shrinkage

    PubMed Central

    Rieger, J.; Twardziok, S.; Huenigen, H.; Hirschberg, R.M.; Plendl, J.

    2013-01-01

    Staining of mast cells (MCs), including porcine ones, is critically dependent upon the fixation and staining technique. In the pig, mucosal and submucosal MCs do not stain or stain only faintly after formalin fixation. Some fixation methods are particularly recommended for MC staining, for example the fixation with Carnoy or lead salts. Zinc salt fixation (ZSF) has been reported to work excellently for the preservation of fixation-sensitive antigens. The aim of this study was to establish a reliable histological method for counting of MCs in the porcine intestinum. For this purpose, different tissue fixation and staining methods that also allow potential subsequent immunohistochemical investigations were evaluated in the porcine mucosa, as well as submucosa of small and large intestine. Tissues were fixed in Carnoy, lead acetate, lead nitrate, Zamboni and ZSF and stained subsequently with either polychromatic methylene blue, alcian blue or toluidine blue. For the first time our study reveals that ZSF, a heavy metal fixative, preserves metachromatic staining of porcine MCs. Zamboni fixation was not suitable for histochemical visualization of MCs in the pig intestine. All other tested fixatives were suitable. Alcian blue and toluidine blue co-stained intestinal goblet cells which made a prima facie identification of MCs difficult. The polychromatic methylene blue proved to be the optimal staining. In order to compare MC counting results of the different fixation methods, tissue shrinkage was taken into account. As even the same fixation caused shrinkagedifferences between tissue from small and large intestine, different factors for each single fixation and intestinal localization had to be calculated. Tissue shrinkage varied between 19% and 57%, the highest tissue shrinkage was found after fixation with ZSF in the large intestine, the lowest one in the small intestine after lead acetate fixation. Our study emphasizes that MC counting results from data using different

  4. 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

  5. A new fixation technique for the Lapidus bunionectomy.

    PubMed

    Wang, James C; Riley, Brendan M

    2005-01-01

    Presented here is a preliminary report of 102 patients who underwent first metatarsocuneiform joint arthrodeses performed with external fixation for the correction of hallux valgus. The advantages of using external fixation are the ability to initiate early weightbearing, predictable fusion, and removal of all of the hardware postoperatively. In the 102 patients reported here, the average time to initiation of unassisted full weightbearing was 13.1 days. The average time to fusion was 5.3 weeks, with removal of the external fixator at an average of 5.5 weeks postoperatively. There was no incidence of delayed union or nonunion. There was one case of pin-tract irritation, which resolved with appropriate pin care and a short course of oral antibiotics. External fixation is an effective alternative to traditional internal fixation techniques in metatarsocuneiform joint arthrodesis.

  6. Acrylic Resin Molding Based Head Fixation Technique in Rodents.

    PubMed

    Roh, Mootaek; Lee, Kyungmin; Jang, Il-Sung; Suk, Kyoungho; Lee, Maan-Gee

    2016-01-12

    Head fixation is a technique of immobilizing animal's head by attaching a head-post on the skull for rigid clamping. Traditional head fixation requires surgical attachment of metallic frames on the skull. The attached frames are then clamped to a stationary platform resulting in immobilization of the head. However, metallic frames for head fixation have been technically difficult to design and implement in general laboratory environment. In this study, we provide a novel head fixation method. Using a custom-made head fixation bar, head mounter is constructed during implantation surgery. After the application of acrylic resin for affixing implants such as electrodes and cannula on the skull, additional resins applied on top of that to build a mold matching to the port of the fixation bar. The molded head mounter serves as a guide rails, investigators conveniently fixate the animal's head by inserting the head mounter into the port of the fixation bar. This method could be easily applicable if implantation surgery using dental acrylics is necessary and might be useful for laboratories that cannot easily fabricate CNC machined metal head-posts.

  7. Suture Bridge Fixation Technique for Posterior Cruciate Ligament Avulsion Fracture.

    PubMed

    Lee, Kwang Won; Yang, Dae Suk; Lee, Gyu Sang; Choy, Won Sik

    2015-12-01

    We presented a surgical technique including a suture bridge technique with relatively small incision for the reduction and fixation of posterior ligament avulsion fractures. A suture anchor was used to hold the avulsed fragment and a knotless anchor was used to continuously compress the bony fragment into the fracture site, thereby maintaining reduction during healing.

  8. Callus Formation and Mineralization after Fracture with Different Fixation Techniques: Minimally Invasive Plate Osteosynthesis versus Open Reduction Internal Fixation.

    PubMed

    Xu, Haitao; Xue, Zichao; Ding, Haoliang; Qin, Hui; An, Zhiquan

    2015-01-01

    Minimally invasive plate osteosynthesis(MIPO) has been considered as an alternative for fracture treatment. Previous study has demonstrated that MIPO technique has the advantage of less soft tissue injury compared with open reduction internal fixation (ORIF). However, the comparison of callus formation and mineralization between two plate osteosynthesis methods remains unknown. In this experiment, ulna fracture model was established in 42 beagle dogs. The fractures underwent reduction and internal fixation with MIPO or ORIF. Sequential fluorescent labeling and radiographs were applied to determine new callus formation and mineralization in two groups after operation. At 4, 8 and 12 weeks postoperatively, the animals were selected to be sacrificed and the ulna specimens were analyzed by Micro-CT. The sections were also treated with Masson staining for histological evaluation. More callus formation was observed in MIPO group in early stage of fracture healing. The fracture union rate has no significant difference between two groups. The results indicate that excessive soft tissue stripping may impact early callus formation. As MIPO technique can effectively reduce soft tissue injury with little incision, it is considered to be a promising alternative for fracture fixation.

  9. Callus Formation and Mineralization after Fracture with Different Fixation Techniques: Minimally Invasive Plate Osteosynthesis versus Open Reduction Internal Fixation

    PubMed Central

    Ding, Haoliang; Qin, Hui; An, Zhiquan

    2015-01-01

    Minimally invasive plate osteosynthesis(MIPO) has been considered as an alternative for fracture treatment. Previous study has demonstrated that MIPO technique has the advantage of less soft tissue injury compared with open reduction internal fixation (ORIF). However, the comparison of callus formation and mineralization between two plate osteosynthesis methods remains unknown. In this experiment, ulna fracture model was established in 42 beagle dogs. The fractures underwent reduction and internal fixation with MIPO or ORIF. Sequential fluorescent labeling and radiographs were applied to determine new callus formation and mineralization in two groups after operation. At 4, 8 and 12 weeks postoperatively, the animals were selected to be sacrificed and the ulna specimens were analyzed by Micro-CT. The sections were also treated with Masson staining for histological evaluation. More callus formation was observed in MIPO group in early stage of fracture healing. The fracture union rate has no significant difference between two groups. The results indicate that excessive soft tissue stripping may impact early callus formation. As MIPO technique can effectively reduce soft tissue injury with little incision, it is considered to be a promising alternative for fracture fixation. PMID:26444295

  10. Epidural catheter fixation. A comparison of subcutaneous tunneling versus device fixation technique

    PubMed Central

    Sharma, Ashima; Parasa, Sujay Kumar; Tejvath, Kiran; Ramachandran, Gopinath

    2016-01-01

    Background and Aims: The technique of securing the epidural catheter has a major bearing on the efficacy of epidural analgesia. Specific fixator devices, for e.g., Lockit epidural catheter clamp, which successfully prevents catheter migration, are available. The possibility of catheter snapping and surgical retrieval has been reported with tunneling of catheters. These techniques have not been compared for safety, efficacy and appropriateness of achieving secure epidural catheter fixation in the postoperative period. Material and Methods: A total of 200 patients who required postoperative epidural analgesia were included. They were randomized into two groups: Group I (n = 100) in whom epidural catheters were tunneled vertically in the paravertebral subcutaneous tissue and group II (n = 100) wherein a Lockit device was used to fix the catheter. Likert score was used to quantify patient's comfort during procedure. The techniques were compared for migration, catheter dislodgement, local trauma, catheter snapping and catheter obstruction. Results: 12% of tunneled catheters had migrated significantly outward. 22% of patients had erythema and 77% had significant procedural discomfort in group I. In group II, 3% catheters had kinked and 14% had erythema from device adhesive. Conclusion: Our results support the use of Lockit device as a safe and comfortable fixation device compared to subcutaneous tunneling of catheters. PMID:27006544

  11. Biomechanical evaluation of four different posterior screw and rod fixation techniques for the treatment of the odontoid fractures

    PubMed Central

    Li, Lei; Liu, Wen-Fei; Jiang, Hong-Kun; Li, Yun-Peng

    2015-01-01

    Problems that screw cannot be inserted may occur in screw-rod fixation techniques such as Harms technique. We compared the biomechanical stability imparted to the C-2 vertebrae by four designed posterior screw and rod fixation techniques for the management of odontoid fractures. A three-dimensional finite element model of the odontoid fracture was established by subtracting several unit structures from the normal model from a healthy male volunteer. 4 different fixation techniques, shown as follows: ① C-1 lateral mass and C-2 pedicle screw fixation (Harms technique); ② C-1 lateral mass and unilateral C-2 pedicle screw fixation combined with ipsilateral laminar screw fixation; ③ Unilateral C-1lateral mass combined with ipsilateral C-1 posterior arch, and C-2 pedicle screw fixation; and ④ Unilateral C1 lateral mass screw connected with bilateral C2 pedicle screw fixation was performed on the odontoid fracture model. The model was validated for axial rotation, flexion, extension, lateral bending, and tension for 1.5 Nm. Changes in motion in flexion-extension, lateral bending, and axial rotation were calculated. The finite element model of the odontoid fracture was established in this paper. All of the four screw-rod techniques significantly decreased motion in flexion-extension, lateral bending, and axial rotation, as compared with the destabilized odontoid fracture complex (P<0.05). There was no statistically significant difference in stability among the four screw techniques. We concluded that the first three fixation techniques are recommended to be used as surgical intervention for odontoid fracture, while the last can be used as supplementary for the former three methods. PMID:26309508

  12. Temporary intra-operative reduction techniques for tibial fracture fixation: A review of the literature.

    PubMed

    Beazley, J C; Hull, P

    2010-12-01

    Accurate intra-operative reduction and maintenance of reduction is essential for successful fixation of tibial fractures. Although many tibial fractures can be reduced with minimal manipulation, numerous techniques have been described to facilitate fixation of more difficult fractures. These include use of a traction table, manual traction techniques, temporary distracters, reduction clamps and temporary unicortical plating. This article reviews the literature and assesses the options available for the temporary reduction and maintenance of reduction of tibial fractures prior to definitive fixation.

  13. Hamstring graft fixation in MPFL reconstruction at the patella using a transosseous suture technique.

    PubMed

    Siebold, Rainer; Chikale, Shivanand; Sartory, Nico; Hariri, Nawid; Feil, Sven; Pässler, Hans H

    2010-11-01

    Controversy still exists about fixation methods of a hamstring graft to the patella in case of medial patellofemoral ligament (MPFL) reconstruction. This article presents a surgical technique of hamstring tendon graft fixation to the anatomical MPFL insertion on the patella using transosseous sutures. A superficial bony sulcus is created at the anatomical MPFL insertion site on the medial patellar rim with a bur. A looped hamstring tendon graft is fixed to this superficial sulcus by a pair of nonresorbable transosseous sutures passed across the patella. The retinaculum is sutured on top of the hamstring tendon graft at the level of the patella for additional fixation. The technique avoids bone tunnels as well as hardware at the patella. It reduces the risk of intraoperative or postoperative patella fracture or implant-related complications. The stable transosseous fixation technique allows for early rehabilitation.

  14. Biomechanical analyses of static and dynamic fixation techniques of retrograde interlocking femoral nailing using nonlinear finite element methods.

    PubMed

    Shih, Kao-Shang; Hsu, Ching-Chi; Hsu, Tzu-Pin; Hou, Sheng-Mou; Liaw, Chen-Kun

    2014-02-01

    Femoral shaft fractures can be treated using retrograde interlocking nailing systems; however, fracture nonunion still occurs. Dynamic fixation techniques, which remove either the proximal or distal locking screws, have been used to solve the problem of nonunion. In addition, a surgical rule for dynamic fixation techniques has been defined based on past clinical reports. However, the biomechanical performance of the retrograde interlocking nailing systems with either the traditional static fixation technique or the dynamic fixation techniques has not been investigated by using nonlinear numerical modeling. Three-dimensional nonlinear finite element models were developed, and the implant strength, fixation stability, and contact area of the fracture surfaces were evaluated. Three types of femoral shaft fractures (a proximal femoral shaft fracture, a middle femoral shaft fracture, and a distal femoral shaft fracture) fixed by three fixation techniques (insertion of all the locking screws, removal of the proximal locking screws, or removal of the distal locking screws) were analyzed. The results showed that the static fixation technique resulted in sufficient fixation stability and that the dynamic fixation techniques decreased the failure risk of the implant and produced a larger contact area of the fracture surfaces. The outcomes of the current study could assist orthopedic surgeons in comprehending the biomechanical performances of both static and dynamic fixation techniques. In addition, the surgeons could also select a fixation technique based on the specific patient situation using the numerical outcomes of this study.

  15. Traumatic lumbar hernia repair: a laparoscopic technique for mesh fixation with an iliac crest suture anchor.

    PubMed

    Links, D J R; Berney, C R

    2011-12-01

    Traumatic lumbar hernia (TLH) is a rare presentation. Traditionally, these have been repaired via an open approach. Recurrence can be a problem due to the often limited tissue available for mesh fixation at the inferior aspect of the hernia defect. We report the successful use of bone suture anchors placed in the iliac crest during transperitoneal laparoscopy for mesh fixation to repair a recurrent TLH. This technique may be particularly useful after previous failed attempts at open TLH repair.

  16. New two-point scleral-fixation technique for foldable intraocular lenses with four hollow haptics.

    PubMed

    Liu, He-Ting; Jiang, Zheng-Xuan; Tao, Li-Ming

    2016-01-01

    The study was to report a new two-point scleral-fixation technique for foldable intraocular lenses with four haptics. Lenses were slid into the anterior chamber from a 2.8 mm corneal incision and fixed under two sclera flaps at two opposite points. The postoperative best-corrected visual acuities (BCVAs) of all patients were significantly better than their preoperative BCVA. The results demonstrate that two-point, scleral fixations of foldable, intraocular lenses might be practicable and effective.

  17. Autologous Hamstring Anterior Cruciate Ligament Graft Failure Using the Anteromedial Portal Technique With Suspensory Femoral Fixation

    PubMed Central

    Galdi, Balazs; Reyes, Allan; Brabston, Eugene W.; Levine, William N.

    2015-01-01

    Background: The anteromedial portal technique for drilling of the femoral tunnel during anterior cruciate ligament (ACL) reconstruction has been advocated by many surgeons as allowing improved access to the anatomical footprint. Furthermore, suspensory fixation of soft tissue grafts has become popularized because of complications associated with cross-pin fixation. Concerns regarding the use of both have recently arisen. Purpose: To raise awareness of the increased risk of graft failure when using the anteromedial portal technique with suspensory femoral fixation during ACL reconstruction. Study Design: Cohort study; Level of evidence, 3. Methods: From November 1998 to August 2012, a total of 465 primary ACL reconstructions were performed using quadrupled hamstring autograft tendons, with drilling of the femoral tunnel performed via the transtibial portal. Graft fixation on the femur was achieved with cross-pin fixation, while interference screw fixation was used on the tibia. From September 2012 to October 2013, there were 69 reconstructions performed through an anteromedial portal. While there was no change in graft choice, a change was made to using suspensory femoral fixation. No other surgical or postoperative rehabilitation changes were made. Results: During the 14-year period in which ACL reconstructions were performed via the transtibial portal and with cross-pin fixation, 2 graft failures (0.4% failure rate) were reported. After switching to the anteromedial portal with suspensory fixation, 7 graft failures (10.1% failure rate) were reported over a 13-month period. These were 5 male and 2 female patients, with a mean age of 18.8 years—all elite athletes. The same surgical technique was used in all patients, and all patients had at least an 8 mm–diameter graft. Patients were cleared to return to sport at an average of 8.4 months postoperatively, after completing functional performance tests. Of the 7 patients, 6 sustained a rerupture of the graft within

  18. A comparative study of fixation techniques for type II fractures of the odontoid process.

    PubMed

    Graziano, G; Jaggers, C; Lee, M; Lynch, W

    1993-12-01

    Primary screw fixation of a Type II odontoid fracture or non-union is an attractive alternative to posterior atlanto-axial arthrodesis in that normal cervical motion can be maintained. Eight cervical cadaver spines, ranging in age from 17-90 years, were used for study. Type II fractures of the dens were created using an osteotome. Simulated fractures were fixed using one or two 3.5-mm bone screws. After testing each screw fixation technique, the screws were removed and a posterior C1-C2 brooks sublaminar wiring was performed using four 18-gauge wires with wooden blocks to simulate bone graft. No significant differences were found between bending and torsional stiffnesses for the one-screw and two-screw specimens. No significant differences were found between one- and two-screw fixation when compared with primary C1-C2 wiring in torsion. One- or two-screw fixation was as stiff as primary C1-C2 wiring in bending. One or two screws offers similar stability for fixation for a dens fracture. One- and two-screw fixation is at least as stiff as primary C1-C2 wiring in torsion and one- or two-screw fixation is stiffer than primary C1-C2 wiring in bending. PMID:8303437

  19. Concurrent Minimally Invasive Carpal Tunnel Release Techniques in Distal Radius Open Reduction Internal Fixation.

    PubMed

    Low, O-Wern; Cheah, Andre E J

    2016-02-01

    Carpal tunnel syndrome is a common complication associated with distal radius fractures. Open carpal tunnel release in the same setting as open reduction and internal fixation of distal radius fractures is widely accepted. In this paper, we describe the technical details of a minimally invasive carpal tunnel release in the same setting as the fixation of a distal radius fracture via the same incision. Two options of minimally invasive techniques are described: The Knifelight® (Stryker, Kalamazoo, Michigan, USA) instrument and the single portal carpal tunnel release system (Agee, 3M Healthcare, St Paul, Minnesota, USA). Being well known and accepted techniques of carpal tunnel release, we believe that the techniques described in this paper provide a viable alternative for carpal tunnel release in the setting of distal radius fracture fixation; with the added advantages of the original minimally invasive techniques. PMID:27454517

  20. Aerobic rice mechanization: techniques for crop establishment

    NASA Astrophysics Data System (ADS)

    Khusairy, K. M.; Ayob, H.; Chan, C. S.; Fauzi, M. I. Mohamed; Mohamad Fakhrul, Z. O.; Shahril Shah, G. S. M.; Azlan, O.; Rasad, M. A.; Hashim, A. M.; Arshad, Z.; E, E. Ibrahim; Saifulizan, M. N.

    2015-12-01

    Rice being the staple food crops, hundreds of land races in it makes the diversity of rice crops. Aerobic rice production was introduced which requires much less water input to safeguard and sustain the rice production and conserve water due to decreasing water resources, climatic changes and competition from urban and industrial users. Mechanization system plays an important role for the success of aerobic rice cultivation. All farming activities for aerobic rice production are run on aerobic soil conditions. Row seeder mechanization system is developed to replace conventional seeding technique on the aerobic rice field. It is targeted for small and the large scale aerobic rice farmers. The aero - seeder machine is used for the small scale aerobic rice field, while the accord - seeder is used for the large scale aerobic rice field. The use of this mechanization machine can eliminate the tedious and inaccurate seeding operations reduce labour costs and increases work rate. The machine is easy to operate and it can increase crop establishment rate. It reduce missing hill, increasing planting and crop with high yield can be produce. This machine is designed for low costs maintenance and it is easy to dismantle and assemble during maintenance and it is safe to be used.

  1. 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

  2. Cortical and Standard Trajectory Pedicle Screw Fixation Techniques in Stabilizing Multisegment Lumbar Spine with Low Grade Spondylolisthesis

    PubMed Central

    İnceoğlu, Serkan

    2015-01-01

    Background Cortical screw (CS) fixation has been recently proposed as an alternative to the standard pedicle screw (PS) fixation technique. Biomechanical studies involving individual screw pullout and single level motion segment stabilization showed comparable performance of both techniques. However, whether this new fixation technique can be applied to the stabilization of multilevel lumbar segments with significant destabilization has been unclear. Purpose To compare stability of CS fixation to the traditional PS fixation in an unstable 3 level spondylolisthesis model. Study Design This is a biomechanical study comparing cortical trajectory pedicle screw fixation to traditional trajectory pedicle screw fixation in an unstable cadaveric model using nondestructive flexibility test. Methods Eight fresh frozen cadaveric lumbar spines (T12- S1) were obtained. After intact baseline testing, a 3-level lowgrade spondylolisthesis was simulated at the L1-4. Each specimen was instrumented with the PS and CS fixation systems. Standard nondestructive flexibility test was performed. Range of motion at each level was compared between the constructs during flexion-extension, lateral bending, and axial rotation. Results The destabilization model significantly increased the ROM in all planes (P<0.05). Both fixation techniques provided significant reduction in the ROM (P<0.05). There was no significant difference in ROM between the PS and CS groups in any of planes (P>0.05). Conclusions Cortical trajectory pedicle screw fixation provided stabilization to multilevel lumbar segment with low-grade spondylolisthesis comparable to the standard trajectory pedicle screw construct. PMID:26484009

  3. New two-point scleral-fixation technique for foldable intraocular lenses with four hollow haptics

    PubMed Central

    Liu, He-Ting; Jiang, Zheng-Xuan; Tao, Li-Ming

    2016-01-01

    The study was to report a new two-point scleral-fixation technique for foldable intraocular lenses with four haptics. Lenses were slid into the anterior chamber from a 2.8 mm corneal incision and fixed under two sclera flaps at two opposite points. The postoperative best-corrected visual acuities (BCVAs) of all patients were significantly better than their preoperative BCVA. The results demonstrate that two-point, scleral fixations of foldable, intraocular lenses might be practicable and effective. PMID:27158623

  4. Technique for reduction and percutaneous fixation of U- and H-shaped sacral fractures.

    PubMed

    Ruatti, S; Kerschbaumer, G; Gay, E; Milaire, M; Merloz, P; Tonetti, J

    2013-09-01

    We describe an early reduction and percutaneous fixation technique for isolated sacral fractures. Strong manual traction combined with manual counter-traction on the torso is used to disimpact the fracture. Transcondylar traction is then applied bilaterally and two ilio-sacral screws are inserted percutaneously on each side. Open reduction and fixation, with sacral laminectomy in patients with neurological abnormalities, remains the reference standard. Early reduction and percutaneous fixation ensures restoration of the pelvic parameters while minimising soft-tissue damage and the risk of infection. Decompression procedures can be performed either during the same surgical procedure after changing the installation or after a few days. These complex fractures warrant patient referral to specialised reference centres.

  5. 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.

  6. 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

  7. Novel Longitudinal Plate-Fixation Technique after Gross Resection of the Sternum

    PubMed Central

    Tasoglu, Irfan; Lafci, Gokhan

    2012-01-01

    Herein, we describe a plate-fixation technique as an alternative method to close a fragile or fractured sternum. A 69-year-old obese woman with diabetes mellitus and chronic obstructive pulmonary disease underwent coronary artery bypass grafting. One week postoperatively, sternal instability was detected, and traditional rewiring was performed. A week later, because of multiple sternal fractures, we performed sternal resection, with use of longitudinally affixed titanium plates and figure-8 steel wires for the anterior chest wall. The procedure was uneventful, and, on short-term follow-up, the anterior chest wall was stable. This longitudinal plate-fixation technique can be tailored to each patient. We think that the technique is safe, effective, economical, and easy to implement, and it is readily reproducible. To evaluate any associated risks, long-term follow-up in additional patients is warranted. PMID:22740734

  8. Interference screw fixation and short harvest using flexor digitorum longus (FDL) transfer for posterior tibial tendon dysfunction: a technique.

    PubMed

    Bussewitz, Bradly W; Hyer, Christopher F

    2010-01-01

    Posterior tibial tendon dysfunction is a common clinical entity treated by foot and ankle specialists, and numerous surgical treatments are available to the modern foot and ankle surgeon. Fixation methods are constantly evolving as new products are developed and new uses for existing products are attempted. Interference screw fixation is the gold standard fixation for tendon autograft and allograft in orthopedic sports medicine. The technique that we describe in this article uses a less extensive harvest of the flexor digitorum longus tendon and a sound fixation method using an interference screw positioned in the tarsal navicular. PMID:20797592

  9. Half-bow sliding knot: modified suture technique for scleral fixation using the corneoscleral pocket.

    PubMed

    Chee, Soon-Phaik

    2011-09-01

    A modified suture technique for precise knot placement in the Hoffman corneoscleral pocket technique of scleral fixation is described. Both loops of the polypropylene suture passing from the intraocular device through the sclera and conjunctiva are retrieved from the pocket. A loop of suture is pulled through 3 suture throws made using the second suture loop, forming a half bow. Centration of the intraocular lens (IOL)-capsular bag is checked. If the suture tension is too tight, the surgeon can easily undo the knot of the half-bow knot by pulling it free and can then retie the sliding knot. When the IOL-capsular bag is centered, the suture loop is cut and the free end removed. The second suture end is retrieved from the pocket, and knot tying is completed without further adjustment to the tension. Posterior pressure on the intraocular device centers it and settles the knot within the sclera at the fixation point.

  10. Multiple Looping Technique for Tibial Fixation in Posterior Cruciate Ligament Reconstruction of the Knee

    PubMed Central

    Noh, Jung Ho; Yoon, Kyoung Ho; Song, Sang Jun; Roh, Young Hak; Lee, Jae Woo

    2015-01-01

    The outcomes of posterior cruciate ligament reconstruction may be negatively affected by insufficient tibial tunnel fixation due to relatively lower bone density of the proximal tibia. We introduce a new technique of tibial fixation for posterior cruciate ligament reconstruction using free tendon Achilles allograft that is less affected by the bone density of the tibial metaphysis. PMID:25973367

  11. Medial Patellofemoral Ligament Reconstruction Using a Femoral Loop Button Fixation Technique

    PubMed Central

    Godin, Jonathan A.; Karas, Vasili; Visgauss, Julia D.; Garrett, William E.

    2015-01-01

    Medial patellofemoral ligament (MPFL) reconstruction is a common procedure used to treat both acute and chronic patellar instability. Although many variations of MPFL reconstruction have been described, there is no consensus regarding the optimal surgical technique. We describe a technique for MPFL reconstruction with a looped gracilis tendon autograft using suture anchors to secure the graft to the patella and a suspensory loop button system for fixation to the femur. This technique replicates the native shape of the MPFL while minimizing the risk of patellar fracture and allowing for gradual tensioning of the graft. PMID:26900561

  12. Tram-Track Suture Technique for Pupillary Capture of a Scleral Fixated Intraocular Lens

    PubMed Central

    Kim, Sung In; Kim, Kiseok

    2016-01-01

    Purpose To report a new technique using tram-track suture for pupillary capture of a scleral fixated posterior chamber intraocular lens (PC-IOL) to reposition the tilted IOL. Methods In this prospective interventional case series, we describe a tram-track suture for pupillary capture of a scleral fixated PC-IOL. A long straight needle with double-armed 10-0 polypropylene is passed behind the iris and just above the optic portion (tilted forward) of the IOL. The other straight needle with double-armed 10-0 polypropylene is passed just below the optic portion (tilted backward) of the IOL. After the IOL is repositioned properly, the polypropylene sutures are gently pulled and tied. Results Four eyes of 4 patients underwent tram-track suture for pupillary capture of a scleral fixated PC-IOL. No intra- or postoperative complications were noted, and no pupillary captures were detected during the follow-up period. Conclusions The tram-track suture technique provides good centration and stability of a PC-IOL. This technique is an easy and effective way to reposition pupillary capture of an IOL. Further, it is also minimally invasive as it maintains a closed system. PMID:27462257

  13. Two-Tension-Band Technique in Revision Surgery for Fixation Failure of Patellar Fractures.

    PubMed

    Xue, Zichao; Qin, Hui; Ding, Haoliang; Xu, Haitao; An, Zhiquan

    2016-01-01

    BACKGROUND Failed patellar fracture fixation is rare, and is usually attributed to technical errors. There are no specific details available on how to address this problem. We present our two-tension-band technique for fixing patellar fractures. MATERIAL AND METHODS Between March 2010 and March 2013, 4 men and 2 women with failed fixation patellar fractures were treated in our department. Their average age was 34 years (range 23-49 years). The initial fracture type was C1 in 3, C2 in 1, and C3 in 2, according to the AO classification. The initial fracture patterns included 3 transverse and 3 comminuted fractures. There were no open fractures. All patients underwent internal fixation with a modified anterior tension band (MATB) supplemented with cerclage wiring. All failures were caused by tension bands sliding past the tip of the Kirschner wires. The mean time between the primary and revision operations was 16.2 months (range 2-63 months). We revised the fractures by two-separate-tension-band technique. RESULTS The mean follow-up was 52 months (range 31-67 months). All patients healed radiographically without complications at an average of 14.7 weeks (range 8-20 weeks). The Bostman knee score was excellent in 3 and good in 3. All patients regained full extension and the mean range of flexion was 147.5° (135-155°). CONCLUSIONS Use of this two-tension-band technique can avoid technical errors and provide more secure fixation. We recommend it for both primary and revision surgery of patellar fractures. PMID:27485104

  14. Two-Tension-Band Technique in Revision Surgery for Fixation Failure of Patellar Fractures.

    PubMed

    Xue, Zichao; Qin, Hui; Ding, Haoliang; Xu, Haitao; An, Zhiquan

    2016-01-01

    BACKGROUND Failed patellar fracture fixation is rare, and is usually attributed to technical errors. There are no specific details available on how to address this problem. We present our two-tension-band technique for fixing patellar fractures. MATERIAL AND METHODS Between March 2010 and March 2013, 4 men and 2 women with failed fixation patellar fractures were treated in our department. Their average age was 34 years (range 23-49 years). The initial fracture type was C1 in 3, C2 in 1, and C3 in 2, according to the AO classification. The initial fracture patterns included 3 transverse and 3 comminuted fractures. There were no open fractures. All patients underwent internal fixation with a modified anterior tension band (MATB) supplemented with cerclage wiring. All failures were caused by tension bands sliding past the tip of the Kirschner wires. The mean time between the primary and revision operations was 16.2 months (range 2-63 months). We revised the fractures by two-separate-tension-band technique. RESULTS The mean follow-up was 52 months (range 31-67 months). All patients healed radiographically without complications at an average of 14.7 weeks (range 8-20 weeks). The Bostman knee score was excellent in 3 and good in 3. All patients regained full extension and the mean range of flexion was 147.5° (135-155°). CONCLUSIONS Use of this two-tension-band technique can avoid technical errors and provide more secure fixation. We recommend it for both primary and revision surgery of patellar fractures.

  15. Two-Tension-Band Technique in Revision Surgery for Fixation Failure of Patellar Fractures

    PubMed Central

    Xue, Zichao; Qin, Hui; Ding, Haoliang; Xu, Haitao; An, Zhiquan

    2016-01-01

    Background Failed patellar fracture fixation is rare, and is usually attributed to technical errors. There are no specific details available on how to address this problem. We present our two-tension-band technique for fixing patellar fractures. Material/Methods Between March 2010 and March 2013, 4 men and 2 women with failed fixation patellar fractures were treated in our department. Their average age was 34 years (range 23–49 years). The initial fracture type was C1 in 3, C2 in 1, and C3 in 2, according to the AO classification. The initial fracture patterns included 3 transverse and 3 comminuted fractures. There were no open fractures. All patients underwent internal fixation with a modified anterior tension band (MATB) supplemented with cerclage wiring. All failures were caused by tension bands sliding past the tip of the Kirschner wires. The mean time between the primary and revision operations was 16.2 months (range 2–63 months). We revised the fractures by two-separate-tension-band technique. Results The mean follow-up was 52 months (range 31–67 months). All patients healed radiographically without complications at an average of 14.7 weeks (range 8–20 weeks). The Bostman knee score was excellent in 3 and good in 3. All patients regained full extension and the mean range of flexion was 147.5° (135–155°). Conclusions Use of this two-tension-band technique can avoid technical errors and provide more secure fixation. We recommend it for both primary and revision surgery of patellar fractures. PMID:27485104

  16. Technique and nuances of an S-2 alar iliac screw for lumbosacral fixation in patients with transitional and normal anatomy.

    PubMed

    Ohya, Junichi; Vogel, Todd D; Dhall, Sanjay S; Berven, Sigurd; Mummaneni, Praveen V

    2016-07-01

    S-2 alar iliac (S2AI) screw fixation has recently been recognized as a useful technique for pelvic fixation. The authors demonstrate two cases where S2AI fixation was indicated: one case was a sacral insufficiency fracture following a long-segment fusion in a patient with a transitional S-1 vertebra; the other case involved pseudarthrosis following lumbosacral fixation. S2AI screws offer rigid fixation, low profile, and allow easy connection to the lumbosacral rod. The authors describe and demonstrate the surgical technique and nuances for the S2AI screw in a case with transitional S-1 anatomy and in a case with normal S-1 anatomy. The video can be found here: https://youtu.be/Sj21lk13_aw . PMID:27364429

  17. Scleral Suture-Fixation Technique for One-Piece Acrylic Intraocular Lens

    PubMed Central

    Leung, Ella H.; Mohsenin, Amir; Smiddy, William E.

    2016-01-01

    Purpose To describe a previously published scleral-fixation technique to secure one-piece acrylic intraocular lenses (IOLs) to the sclera. Methods Retrospective, consecutive, non-comparative case series. Patients 16 eyes of 15 patients Results All patients who underwent scleral-fixation of one-piece acrylic IOLs using the loop method from 2014 to 2016 were included. The mean follow-up was 8.1 months. The dislocated one-piece acrylic IOL was repositioned in 8 eyes, a primary implantation was performed in 5 eyes, and the IOL was exchanged in 3 eyes. All IOLs remained well-centered postoperatively. The vision improved from an initial best corrected visual acuity of 0.97 ± 0.74 logMAR (Snellen equivalent ≈20/190) to 0.47 ± 0.49 logMAR (≈20/60, P=0.031) at the last follow-up. The post-operative complications were self-limited. Conclusions The previously reported scleral suture-fixation technique can be readily applied to one-piece acrylic IOLs. PMID:17278543

  18. Strength analysis of clavicle fracture fixation devices and fixation techniques using finite element analysis with musculoskeletal force input.

    PubMed

    Marie, Cronskär

    2015-08-01

    In the cases, when clavicle fractures are treated with a fixation plate, opinions are divided about the best position of the plate, type of plate and type of screw units. Results from biomechanical studies of clavicle fixation devices are contradictory, probably partly because of simplified and varying load cases used in different studies. The anatomy of the shoulder region is complex, which makes it difficult and expensive to perform realistic experimental tests; hence, reliable simulation is an important complement to experimental tests. In this study, a method for finite element simulations of stresses in the clavicle plate and bone is used, in which muscle and ligament force data are imported from a multibody musculoskeletal model. The stress distribution in two different commercial plates, superior and anterior plating position and fixation including using a lag screw in the fracture gap or not, was compared. Looking at the clavicle fixation from a mechanical point of view, the results indicate that it is a major benefit to use a lag screw to fixate the fracture. The anterior plating position resulted in lower stresses in the plate, and the anatomically shaped plate is more stress resistant and stable than a regular reconstruction plate.

  19. 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.

  20. Sutureless, Glueless, Scleral Fixation of Single-Piece and Toric Intraocular Lens: A Novel Technique

    PubMed Central

    Kelkar, Aditya; Shah, Rachana; Kelkar, Jai; Kelkar, Shreekant; Arora, Ekta

    2015-01-01

    Sutureless, glueless, scleral fixation of an intraocular lens is a known technique of fixing a lens in the scleral pockets. However, this technique is applied to single-piece and toric lenses instead of 3-piece lenses, allowing the advantage of the use of premium lenses in patients with poor capsular support. Favourable results without complications of pigment dispersion, iris transillumination defects, dysphotopsia, elevated intraocular pressure, intraocular hemorrhage and cystoid macular edema with a well-centered, stable intraocular lens have been observed in the 3-month postoperative period in both cases. PMID:26327909

  1. Sutureless, Glueless, Scleral Fixation of Single-Piece and Toric Intraocular Lens: A Novel Technique.

    PubMed

    Kelkar, Aditya; Shah, Rachana; Kelkar, Jai; Kelkar, Shreekant; Arora, Ekta

    2015-01-01

    Sutureless, glueless, scleral fixation of an intraocular lens is a known technique of fixing a lens in the scleral pockets. However, this technique is applied to single-piece and toric lenses instead of 3-piece lenses, allowing the advantage of the use of premium lenses in patients with poor capsular support. Favourable results without complications of pigment dispersion, iris transillumination defects, dysphotopsia, elevated intraocular pressure, intraocular hemorrhage and cystoid macular edema with a well-centered, stable intraocular lens have been observed in the 3-month postoperative period in both cases.

  2. Revisiting fixation and embedding techniques for optimal detection of dendritic cell subsets in tissues.

    PubMed

    Accart, Nathalie; Sergi, Florinda; Rooke, Ronald

    2014-09-01

    Organ-specific cell types are maintained by tissue homeostasis and may vary in nature and/or frequency in pathological situations. Moreover, within a cell lineage, some sub-populations, defined by combinations of cell-surface markers, may have specific functions. Dendritic cells are the epitome of such a population as they may be subdivided into discrete sub-groups with defined functions in specific compartments of various organs. Technically, to study the distribution of DC sub-populations, it involves performing multiparametric immunofluorescence on well-conserved organ structures. However, immunodetection may be impacted by protein cross-linking and antigenic epitope masking by the use of 10% neutral-buffered formalin. To circumvent this and to preserve a good morphological tissue structure, we evaluated alternative fixatives such as Periodate Lysine Paraformaldehyde or Tris Zinc fixatives in combination with other embedding techniques. The cryosection protocols were adapted for optimal antigen detection but offered a poor morphological preservation. We therefore developed a new methodology based on Tris Zinc fixative, gelatin-sucrose embedding and freezing. Using multiple DC markers, we demonstrate that this treatment is an optimal protocol for cell-surface marker detection on high-quality tissue sections. PMID:24874853

  3. Biomechanical Evaluation of All-Polyethylene Pegged Bony Ingrowth Glenoid Fixation Techniques on Implant Micromotion.

    PubMed

    Wiater, Brett P; Moravek, James E; Kurdziel, Michael D; Baker, Kevin C; Wiater, J Michael

    2016-01-01

    Newer glenoid components that allow for hybrid cement fixation via traditional cementation of peripheral pegs and bony ingrowth into an interference-fit central peg introduce the possibility of long-term biological fixation. However, little biomechanical work has been done on the initial stability of these components and the various fixation options. We conducted a study in which all-polyethylene glenoid components with a centrally fluted peg were implanted in polyurethane blocks with interference-fit, hybrid cement, and fully cemented fixation (5 per fixation group). Biomechanical evaluation of glenoid loosening, according to ASTM Standard F-2028-12, subjected the glenoids to 50,000 cycles of rim loading, and glenoid component motion was recorded with 2 differential variable reluctance transducers fixed to each glenoid prosthesis. Fully cemented fixation exhibited significantly less mean distraction in comparison with interference-fit fixation (P < .001) and hybrid cement fixation (P < .001). Hybrid cement fixation exhibited significantly less distraction (P < .001), more compression (P < .001), and no significant difference in glenoid translation (P = .793) in comparison with interference-fit fixation. Fully cemented fixation exhibited the most resistance to glenoid motion in comparison with hybrid cement fixation and interference-fit fixation. However, hybrid cement fixation and interference-fit fixation exhibited equivocal motion. Given these results, cementation of peripheral pegs may confer no additional initial stability over that provided by uncemented interference-fit fixation. PMID:27327928

  4. Three-wire fixation technique for displaced fifth metatarsal base fractures.

    PubMed

    Thomas, James L; Davis, Barry C

    2011-01-01

    Fractures of the tuberosity of the fifth metatarsal are the most common type of fifth metatarsal fractures. This particular fracture usually produces low morbidity and low rates of nonunion when treated nonoperatively. However, on occasion, significant displacement, comminution, or significant intra-articular involvement may warrant operative intervention. Multiple techniques have been described for the operative care of this fracture. We present a somewhat simplified fixation method for displaced fifth metatarsal fractures in a small set of patients who were all followed up to final healing of the fracture.

  5. Application of "cinch/tie" technique to robotic-assisted nephropexy for posterior abdominal wall fixation.

    PubMed

    Castle, Scott M; Karnjanawanichkul, Watid; Leveillee, Raymond J

    2012-06-01

    Nephropexy remains standard for symptomatic nephroptosis, and several minimally-invasive techniques have been described. Triangulation sutures placed between the abdominal wall and the renal capsule are often difficult to tie tightly due to the confined working space. We propose a technique modification to fixate the kidney utilizing the da Vinci Surgical System robot and Lapra-Ty absorbable suture clips. Four female patients with symptomatic nephroptosis diagnosed via kidney hypermobility demonstrated on intravenous urography (IVU) underwent robotic-assisted laparoscopic nephropexy (RALNP) from February 2008 to April 2010. After complete mobilization and stripping of perirenal fat, several 0 Vicryl sutures were placed in a "figure of eight" fashion and tied loosely. Subsequently we utilized a Lapra-Ty to tighten the stitch serially and fixate the kidney. The mean age was 46 years (43-52); one patient underwent simultaneous pyeloplasty and one underwent partial nephrectomy in the ipsilateral kidney. There were no intraoperative complications and two postoperative complications, both Clavien grade I. All patients were asymptomatic postoperatively at a mean follow-up of 9.2 months (1-28), and had no evidence of kidney hypermobility on upright IVU or diuretic renal scintigraphy (RS) scan at 6 weeks postoperatively. RALNP is a viable option in the treatment of symptomatic nephroptosis. Secure placement of several "pexing" sutures helps to ensure appropriate security of these itinerant kidneys. Our technique modification corrects kidney hypermobility while improving symptoms related to nephroptosis. PMID:27628279

  6. Triangular Fixation Technique for Bicolumn Restoration in Treatment of Distal Humerus Intercondylar Fracture

    PubMed Central

    Kang, Seung-Hoon; Jeong, Min; Lim, Hae-Seong

    2016-01-01

    Background Distal humerus intercondylar fractures are intra-articular and comminuted fractures involving soft tissue injury. As distal humerus is triangle-shaped, parallel plating coupled with articular fixation would be suitable for bicolumn restoration in treatment of distal humerus intercondylar fracture. Methods This study included 38 patients (15 males and 23 females) who underwent olecranon osteotomy, open reduction and internal fixation with the triangle-shaped cannulated screw and parallel locking plates (triangular fixation technique). Functional results were assessed with the visual analog scale (VAS) scores, Mayo elbow performance (MEP) scores and Disabilities of the Arm, Shoulder and Hand (DASH) questionnaires. Anteroposterior and lateral elbow radiographs were assessed for reduction, alignment, fracture union, posttraumatic arthrosis, and heterotopic ossification, and computed tomography (CT) scans were used to obtain more accurate measurements of articular discrepancy. Results All fractures healed primarily with no loss of reduction. The mean VAS, MEP, and DASH scores of the affected elbow were not significantly different from those of the unaffected elbow (p = 0.140, p = 0.090, and p = 0.262, respectively). The mean degree of flexion was significantly lower in the affected elbow than in the unaffected elbow, but was still considered as functional (p = 0.001, > 100° in 33 of 38 patients). Two cases of articular step-offs (> 2 mm) were seen on follow-up CT scans, but not significantly higher in the affected elbow than in the unaffected elbow (p = 0.657). Binary logistic regression analysis revealed that only Association for Osteosynthesis (AO) type C3 fractures correlated with good/excellent functional outcome (p = 0.012). Complications occurred in 12 of the 38 patients, and the overall reoperation rate for complications was 10.5% (4 of 38 patients). Conclusions Triangular fixation technique for bicolumn restoration was an effective and reliable

  7. Secondary Upper Lid Blepharoplasty: A Clinical Series Using the Tarsal Fixation Technique

    PubMed Central

    Mendelson, Bryan C.

    2015-01-01

    Background: One hundred consecutive secondary upper lid blepharoplasties were reviewed retrospectively to determine the lid characteristics of patients undergoing secondary blepharoplasty and the outcomes of all the procedures, which were performed using a tarsal fixation technique performed by one surgeon. Methods: The median age of the patients was 54 years, and 99 percent of the patients were women. The median time since primary blepharoplasty was 8.7 years (range, 2 to 22 years). At surgery, no additional skin was removed in 37 percent, and the median amount excised in the remainder was only 2 mm. Revision surgery was performed in 13 percent, mainly for incomplete correction of asymmetry (5 percent) or ptosis (4 percent). Nonsurgical complications were mainly ocular (8 percent). There were no cases of persistent postoperative lagophthalmos or dry eyes. Results: The term “postblepharoplasty look” was introduced to describe the different aging changes that follow primary blepharoplasty, mainly dermatochalasis (70 percent), with a high or absent and often poorly defined lid fold, with fat distribution irregularities. The tarsal fixation technique is advantageous in secondary blepharoplasty, as its benefit does not depend on further skin removal, minimizing the risk of lagophthalmos and dry eye syndrome. Lipoinfiltration for volume contouring is another major advance. The higher revision rate in secondary blepharoplasty reflects the incidence of asymmetry, lid ptosis, and scar from the original blepharoplasty, and from ongoing aging. Conclusions: The postblepharoplasty look of patients undergoing secondary upper lid blepharoplasty differs from the lid appearance of patients presenting for primary blepharoplasty. Tarsal fixation and lipoinfiltration are major advances in secondary upper lid blepharoplasty. PMID:25719715

  8. Novel intramedullary-fixation technique for long bone fragility fractures using bioresorbable materials.

    PubMed

    Nishizuka, Takanobu; Kurahashi, Toshikazu; Hara, Tatsuya; Hirata, Hitoshi; Kasuga, Toshihiro

    2014-01-01

    Almost all of the currently available fracture fixation devices for metaphyseal fragility fractures are made of hard metals, which carry a high risk of implant-related complications such as implant cutout in severely osteoporotic patients. We developed a novel fracture fixation technique (intramedullary-fixation with biodegradable materials; IM-BM) for severely weakened long bones using three different non-metallic biomaterials, a poly(l-lactide) (PLLA) woven tube, a nonwoven polyhydroxyalkanoates (PHA) fiber mat, and an injectable calcium phosphate cement (CPC). The purpose of this work was to evaluate the feasibility of IM-BM with mechanical testing as well as with an animal experiment. To perform mechanical testing, we fixed two longitudinal acrylic pipes with four different methods, and used them for a three-point bending test (N = 5). The three-point bending test revealed that the average fracture energy for the IM-BM group (PLLA + CPC + PHA) was 3 times greater than that of PLLA + CPC group, and 60 to 200 times greater than that of CPC + PHA group and CPC group. Using an osteoporotic rabbit distal femur incomplete fracture model, sixteen rabbits were randomly allocated into four experimental groups (IM-BM group, PLLA + CPC group, CPC group, Kirschner wire (K-wire) group). No rabbit in the IM-BM group suffered fracture displacement even under full weight bearing. In contrast, two rabbits in the PLLA + CPC group, three rabbits in the CPC group, and three rabbits in the K-wire group suffered fracture displacement within the first postoperative week. The present work demonstrated that IM-BM was strong enough to reinforce and stabilize incomplete fractures with both mechanical testing and an animal experiment even in the distal thigh, where bone is exposed to the highest bending and torsional stresses in the body. IM-BM can be one treatment option for those with severe osteoporosis. PMID:25111138

  9. COMPLICATIONS OF THE SCREW/WASHER TIBIAL FIXATION TECHNIQUE FOR KNEE LIGAMENT RECONSTRUCTION

    PubMed Central

    Almeida, Alexandre; Roveda, Gilberto; Valin, Márcio Rangel; Almeida, Nayvaldo Couto de; Sartor, Vanderlei; Alves, Soraya Melina

    2015-01-01

    To evaluate the presence of pain at the site of the surgical incision and the need to remove the tibial fixation screw in anterior cruciate ligament (ACL) reconstruction, in relation to sex and body mass index (BMI). Methods: A group of 265 patients who underwent ACL reconstruction with ipsilateral flexor tendon grafts from the thigh in which the tibial fixation technique consisted of using a cortical screw and metal washer, between July 2000 and November 2007, were evaluated. Results: 176 patients were evaluated for an average of 33.3 ± 19.5 months; median of 29.5 months; IIQ: 17-45 months; minimum of 8 and maximum of 87 months. There was no statistical difference regarding complaints of pain at the site of the screw (p = 0.272) and the need to remove the tibial screw (p = 0.633) between sexes. There was no statistical difference regarding complaints of pain at the site of the screw (p = 0.08) and the need to remove the tibial screw (p = 0.379) according to BMI. Conclusion: The pain complaint rate at the screw site from the screw and metal washer method used for tibial fixation in ACL reconstruction was of the order of 25%, and the screw had to be removed in 10.8% of the cases. There was no predominance of pain complaints at the surgical wound between the sexes. There was a greater tendency to complain about pain among patients with BMI < 25. There was no predominance of screw and washer removal between the sexes or between individuals with different BMIs. PMID:27022587

  10. Novel Intramedullary-Fixation Technique for Long Bone Fragility Fractures Using Bioresorbable Materials

    PubMed Central

    Nishizuka, Takanobu; Kurahashi, Toshikazu; Hara, Tatsuya; Hirata, Hitoshi; Kasuga, Toshihiro

    2014-01-01

    Almost all of the currently available fracture fixation devices for metaphyseal fragility fractures are made of hard metals, which carry a high risk of implant-related complications such as implant cutout in severely osteoporotic patients. We developed a novel fracture fixation technique (intramedullary-fixation with biodegradable materials; IM-BM) for severely weakened long bones using three different non-metallic biomaterials, a poly(l-lactide) (PLLA) woven tube, a nonwoven polyhydroxyalkanoates (PHA) fiber mat, and an injectable calcium phosphate cement (CPC). The purpose of this work was to evaluate the feasibility of IM-BM with mechanical testing as well as with an animal experiment. To perform mechanical testing, we fixed two longitudinal acrylic pipes with four different methods, and used them for a three-point bending test (N = 5). The three-point bending test revealed that the average fracture energy for the IM-BM group (PLLA + CPC + PHA) was 3 times greater than that of PLLA + CPC group, and 60 to 200 times greater than that of CPC + PHA group and CPC group. Using an osteoporotic rabbit distal femur incomplete fracture model, sixteen rabbits were randomly allocated into four experimental groups (IM-BM group, PLLA + CPC group, CPC group, Kirschner wire (K-wire) group). No rabbit in the IM-BM group suffered fracture displacement even under full weight bearing. In contrast, two rabbits in the PLLA + CPC group, three rabbits in the CPC group, and three rabbits in the K-wire group suffered fracture displacement within the first postoperative week. The present work demonstrated that IM-BM was strong enough to reinforce and stabilize incomplete fractures with both mechanical testing and an animal experiment even in the distal thigh, where bone is exposed to the highest bending and torsional stresses in the body. IM-BM can be one treatment option for those with severe osteoporosis. PMID:25111138

  11. Rapid complement fixation technique for estimating complement-fixing antigen elution profiles of viruses from gel filtration columns.

    PubMed

    Cornesky, R A; Hammon, W M; Sather, G E; Atchison, R

    1972-07-01

    The complement fixation elution profiles of dengue-2 virus-infected suckling mouse brain supernatant fluids from Sephadex G-200 columns were compared by the antigen end-point titration procedure and by a complement dilution technique. The latter technique was found to be a quick method for approximating the complement-fixing antigen in eluates.

  12. A novel technique of lumbar hernia repair using bone anchor fixation.

    PubMed

    Carbonell, A M; Kercher, K W; Sigmon, L; Matthews, B D; Sing, R F; Kneisl, J S; Heniford, B T

    2005-03-01

    Lumbar hernias are difficult to repair due to their proximity to bone and inadequate surrounding tissue to buttress the repair. We analyzed the outcome of patients undergoing a novel retromuscular lumbar hernia repair technique. The repair was performed in ten patients using a polypropylene or polytetrafluoroethylene mesh placed in an extraperitoneal, retromuscular position with at least 5 cm overlap of the hernia defect. The mesh was fixed with circumferential, transfascial, permanent sutures and inferiorly fixed to the iliac crest by suture bone anchors. Five hernias were recurrent, and five were incarcerated; seven were incisional hernias, and three were posttraumatic. Back and abdominal pain was the most common presenting symptom. Mean hernia size was 227 cm(2) (60-504) with a mesh size of 620 cm(2) (224-936). Mean operative time was 181 min (120-269), with a mean blood loss of 128 ml (50-200). Mean length of stay was 5.2 days (2-10), and morphine equivalent requirement was 200 mg (47-460). There were no postoperative complications or deaths. After a mean follow-up of 40 months (3-99) there have been no recurrences. Our sublay repair of lumbar hernias with permanent suture fixation is safe and to date has resulted in no recurrences. Suture bone anchors ensure secure fixation of the mesh to the iliac crest and may eliminate a common area of recurrence.

  13. Reconstruction of multiplanar deformity of the hindfoot and midfoot with internal fixation techniques.

    PubMed

    Dreher, Thomas; Hagmann, Sebastién; Wenz, Wolfram

    2009-09-01

    Reconstruction surgery of the midand hindfoot is a demanding challenge for foot surgeons. Satisfactory results depend not only on surgical technique and skills but also on the knowledge of underlying disorders, pathomechanics, and indication criteria. The cavovarus foot, the planovalgus foot, and Charcot's foot are some of the most challenging foot deformities, requiring different surgical strategies for their correction. Most of the osteotomies and fusions in children and adults can be fixed with transcutaneous Kirschner wires, which are inexpensive and easy to use and remove. The use of alternative fixation systems such as cannulated screws, compression screws, or angle-stable locking plates depends on patient age, vascular situation, risk for nonunion, and underlying pathology.

  14. Biomechanical Comparison Between Bashti Bone Plug Technique and Biodegradable Screw for Fixation of Grafts in Ligament surgery

    PubMed Central

    Bashti, Kaveh; Tahmasebi, Mohammad N; Kaseb, Hasan; Farahmand, Farzam; Akbar, Mohammad; Mobini, Amir

    2015-01-01

    Background: Ligament reconstruction is a common procedure in orthopedic surgery. Although several popular techniques are currently in use, new methods are proposed for secure fixation of the tendon graft into the bone tunnel. Purposes: We sought to introduce our new technique of Bashti bone plug for fixation of soft tissue graft in anterior cruciate ligament (ACL) reconstruction and to compare its biomechanical features with conventional absorbable interference screw technique in a bovine model. Methods: Twenty pairs of bovine knees were harvested after death. Soft tissue was removed and the Achilles tendon was harvested to be used as an ACL graft. It was secured into the bone tunnel on the tibial side via two different methods: Bashti Bone Plug technique and conventional screw method. Biomechanical strength was measured using 200 N and 300 N cyclic loading on the graft. Pull out strength was also tested until the graft fails. Results: No graft failure was observed after 200 N and 300 N cyclic loading in either fixation methods. When testing for pull out failure, 21 tendons (53%) were torn and 19 tendons (48%) slipped out. No fixation failure occurred, which did not reveal a significant difference between the bone plug or interference screw group (P=0.11). The mean pull out force until failure of the graft was 496±66 N in the screw group and 503±67 N in the bone plug group (P=0.76). Conclusions: Our suggested fixation technique of Bashti bone plug is a native, cheap, and feasible method that provides comparable biomechanical strength with interference screw when soft tissue fixation was attempted in bovine model. PMID:25692166

  15. Locking plate fixation of distal femoral fractures is a challenging technique: a retrospective review

    PubMed Central

    Toro, Giuseppe; Calabrò, Giampiero; Toro, Antonio; de Sire, Alessandro; Iolascon, Giovanni

    2015-01-01

    Summary Distal femoral fractures have typically a bimodal occurrence: in young people due to a high-energy trauma and in older people related to a low-energy trauma. These fractures are associated to a very high morbidity and mortality in elderly. Distal femoral fractures might be treated with plates, intramedullary nails, external fixations, and prosthesis. However, difficulties in fracture healing and the rate of complications are important clinical issues. The purpose of this retrospective review was to present our experience in treatment of distal femoral fracture in a sample of older people in order to evaluate the technical pitfalls and strategies used to face up the fractures unsuccessfully treated with locking plates. We included people aged more than 65 years, with a diagnosis of distal femoral fracture, treated with locking plates. We considered ‘unsuccessfully treated’ the cases with healing problems or hardware failures. Of the 12 patients (9 females and 3 males; mean aged 68.75 ± 3.31 years) included, we observed 3 ‘unsuccessfully cases’, 2 due to nonunions and 1 due to an early hardware failure, all treated using a condylar blade plate with a bone graft. One patient obtained a complete fracture healing after 1 year and in the other cases there was a nonunion. We observed as most common technical pitfalls: inadequate plate lengthening, fracture bridging, and number of locking screws. The use of locking plates is an emerging technique to treat these fractures but it seems more challenging than expected. In literature there is a lack of evidences about the surgical management of distal femoral fractures that is still an important challenge for the orthopaedic surgeon that has to be able to use all the fixation devices available. PMID:27134634

  16. A Technique of Superficial Medial Collateral Ligament Reconstruction Using an Adjustable-Loop Suspensory Fixation Device.

    PubMed

    Deo, Shaneel; Getgood, Alan

    2015-06-01

    This report describes superficial medial collateral ligament reconstruction of the knee using a novel method of graft fixation with the ACL Tightrope RT (Arthrex, Naples, FL). After tibial fixation with either a standard interference screw or staple, femoral fixation of the semitendinosus tendon is performed with the adjustable-loop suspensory fixation device, which allows for both initial graft tensioning and re-tensioning after cyclical knee range of motion. This provides the ability for the graft to accommodate for resultant soft-tissue creep and stress relaxation, thereby allowing for optimal soft-tissue tension and reduction in laxity at the end of the procedure. PMID:26258041

  17. A Technique of Superficial Medial Collateral Ligament Reconstruction Using an Adjustable-Loop Suspensory Fixation Device.

    PubMed

    Deo, Shaneel; Getgood, Alan

    2015-06-01

    This report describes superficial medial collateral ligament reconstruction of the knee using a novel method of graft fixation with the ACL Tightrope RT (Arthrex, Naples, FL). After tibial fixation with either a standard interference screw or staple, femoral fixation of the semitendinosus tendon is performed with the adjustable-loop suspensory fixation device, which allows for both initial graft tensioning and re-tensioning after cyclical knee range of motion. This provides the ability for the graft to accommodate for resultant soft-tissue creep and stress relaxation, thereby allowing for optimal soft-tissue tension and reduction in laxity at the end of the procedure.

  18. A Technique of Superficial Medial Collateral Ligament Reconstruction Using an Adjustable-Loop Suspensory Fixation Device

    PubMed Central

    Deo, Shaneel; Getgood, Alan

    2015-01-01

    This report describes superficial medial collateral ligament reconstruction of the knee using a novel method of graft fixation with the ACL Tightrope RT (Arthrex, Naples, FL). After tibial fixation with either a standard interference screw or staple, femoral fixation of the semitendinosus tendon is performed with the adjustable-loop suspensory fixation device, which allows for both initial graft tensioning and re-tensioning after cyclical knee range of motion. This provides the ability for the graft to accommodate for resultant soft-tissue creep and stress relaxation, thereby allowing for optimal soft-tissue tension and reduction in laxity at the end of the procedure. PMID:26258041

  19. “Two-step” technique with OsiriX™ to evaluate feasibility of C2 pedicle for surgical fixation

    PubMed Central

    Marques, Luis Miguel Sousa; d’Almeida, Gonçalo Neto; Cabral, José

    2016-01-01

    Background: Surgical treatment of craniovertebral junction pathology has evolved considerably in recent decades with the implementation of short atlanto-axial fixation techniques, notwhithstanding increasing neurovascular risks. Also, there is strong evidence that fixation of C2 anatomical pedicle has the best biomechanical profile of the entire cervical spine. However, it is often difficult and misleading, to evaluate anatomical bony and vascular anomalies using the three orthogonal planes (axial, coronal, and sagittal) of CT. Objectives: The authors describe an innovative and simple technique to evaluate the feasibility of C2 pedicle for surgical screw fixation using preoperative planning with the free DICOM (Digital Imaging and Communications in Medicine) software OsiriX™. Materials and Methods: The authors report the applicatin of this novel technique in 5 cases (3 traumatic, 1 Os Odontoideum, and 1 complex congenital malformation) collected from our general case series of the Department in the last 5 years. Results: In this proof of concept study, the pre-operative analysis with the two-step tecnique was detrimental for choosing the surgical tecnique. Detailed post-operative analysis confirmed correct position of C2 screws without cortical breach. There were no complications or mortality reported. Conclusion: This two-step technique is an easy and reliable way to determine the feasibility of C2 pedicle for surgical fixation. The detailed tridimensional radiological preoperative evaluation of craniovertebral junction anatomy is critical to the sucess and safety of this surgeries, and can avoid, to certain degree, expensive intra-operative tridimensional imaging facilities. PMID:27217652

  20. Enhanced Lapidus arthrodesis: crossed screw technique with middle cuneiform fixation further reduces sagittal mobility.

    PubMed

    Galli, Melissa M; McAlister, Jeffrey E; Berlet, Gregory C; Hyer, Christopher F

    2015-01-01

    Persistent medial column sagittal mobility can be encountered despite successful first tarsometatarsal stabilization if fixation has been limited to the first tarsometatarsal joint. The purpose of the present cadaveric research was to quantify the effect of a third point of fixation from the base of the first metatarsal to the middle cuneiform compared with the traditional isolated first tarsometatarsal fixation. Ten matched pairs of below-the-knee specimens, with a known cause of death, sex, ethnicity, and age, height, weight, and body mass index at death, were used for our examination. Portable fluoroscopy aided with the accurate placement of all points of fixation. Measurements of movement were obtained using the validated Klaue device. The 20 matched below-the-knee specimens were from 10 cadavers (2 female and 8 male donors, aged 72.8 ± 9.3 years, body mass index 21.1 ± 4.2 kg/m(2)). The sagittal plane motion of the first ray was 7.45 ± 1.82 mm before fixation. With isolated first tarsometatarsal fixation, the sagittal motion decreased to 4.41 ± 1.51 mm and decreased further to 3.12 ± 1.06 mm, with the addition of middle cuneiform fixation. Statistically significant enhancement of the stability of sagittal first ray motion was noted with the addition of the first metatarsal to middle cuneiform pin, even after simulated Lapidus fixation. Our findings suggest that first metatarsal to middle cuneiform fixation can be beneficial if excessive sagittal motion is present after standard 2-point fixation and can play a role in the prevention of recurrence and complications. PMID:25456344

  1. Biplane double-supported screw fixation (F-technique): a method of screw fixation at osteoporotic fractures of the femoral neck.

    PubMed

    Filipov, Orlin

    2011-10-01

    The present work introduces a method of screw fixation of femoral neck fractures in the presence of osteoporosis, according to an original concept of the establishment of two supporting points for the implants and their biplane positioning in the femoral neck and head. The provision of two steady supporting points for the implants and the highly increased (obtuse) angle at which they are positioned allow the body weight to be transferred successfully from the head fragment onto the diaphysis, thanks to the strength of the screws, with the patient's bone quality being of least importance. The position of the screws allows them to slide under stress with a minimal risk of displacement. The method was developed in search of a solution for those patients for whom primary arthroplasty is contraindicated. The method has been analysed in relation to biomechanics and statics. For the first time, a new function is applied to a screw fixation-the implant is presented as a simple beam with an overhanging end.

  2. Review of techniques for monitoring the healing fracture of bones for implementation in an internally fixated pelvis.

    PubMed

    Wong, Lydia Chwang Yuh; Chiu, Wing Kong; Russ, Matthias; Liew, Susan

    2012-03-01

    Sacral fractures from high-impact trauma often cause instability in the pelvic ring structure. Treatment is by internal fixation which clamps the fractured edges together to promote healing. Healing could take up to 12 weeks whereby patients are bedridden to avoid hindrances to the fracture from movement or weight bearing activities. Immobility can lead to muscle degradation and longer periods of rehabilitation. The ability to determine the time at which the fracture is stable enough to allow partial weight-bearing is important to reduce hospitalisation time. This review looks into different techniques used for monitoring the fracture healing of bones which could lead to possible methods for in situ and non-invasive assessment of healing fracture in a fixated pelvis. Traditional techniques being used include radiology and CT scans but were found to be unreliable at times and very subjective in addition to being non in situ. Strain gauges have proven to be very effective for accurate assessment of fracture healing as well as stability for long bones with external fixators but may not be suitable for an internally fixated pelvis. Ultrasound provides in situ monitoring of stiffness recovery but only assesses local fracture sites close to the skin surface and has only been tested on long bones. Vibration analysis can detect non-uniform healing due to its assessment of the overall structure but may suffer from low signal-to-noise ratio due to damping. Impedance techniques have been used to assess properties of non-long bones but recent studies have only been conducted on non-biological materials and more research needs to be done before it can be applicable for monitoring healing in the fixated pelvis.

  3. Prosthetic mesh "slim-cigarette like" for laparoscopic repair of ventral hernias: a new technique without transabdominal fixation sutures.

    PubMed

    Canton, S A; Merigliano, S; Pasquali, C

    2016-06-01

    Prosthetic mesh rolled up and fixed with stitches like a slim cigarette ("slim-mesh") for laparoscopic ventral hernia (VH) repair is an new technique which allows an easy intraperitoneally introduction, distension and circumferential fixation of a prosthetic mesh without transabdominal fixation sutures even for meshes larger than 16 cm up to 30 cm for the "slim-mesh" repair of wide ventral hernias. We report the technique of laparoscopic repair of VH with "slim-mesh". This technique enables an easy intra-peritoneally introduction of the mesh through the trocar because it reduces consistently its size, it allows a rapid intra-abdominal handling of the mesh and a fast and easy fixation for VH repair. The average time of surgery with "slim-mesh" for treatment of all 28 VH was 97 min ranging from 57 to 160 min. The average time for the repair of the 24 VH smaller than 10 cm was 91 and 135 min for the four VH larger than 10-22 cm. This new surgical technique leads to a reduction of surgical risks avoiding the use of transfascial sutures with the associated complications. This new surgical procedure in our experience is fast, safe, simple and also easily reproducible by surgeons in laparoscopic training. This technique may be used in wide VH (larger than 10-22 cm) that generally require open surgery.

  4. Comparison of Hallux Interphalangeal Joint Arthrodesis Fixation Techniques: A Retrospective Multicenter Study.

    PubMed

    Thorud, Jakob C; Jolley, Tyler; Shibuya, Naohiro; Lew, Eric; Britt, Matthew; Butterfield, Ted; Boike, Alan; Hardy, Mark; Brancheau, Steven P; Motley, Travis; Jupiter, Daniel C

    2016-01-01

    Few studies have investigated the complications that occur after hallux interphalangeal joint arthrodesis. The present study evaluated complications in 152 patients aged 18 to 80 years from 2005 to 2012 from 4 different academic institutions after hallux interphalangeal joint arthrodesis. Overall, 65.8% of the patients had ≥1 complication. Infections occurred in 16.5%, dehiscence in 12.5%, and reoperations in 27.0%. The clinical nonunion rate was ≥17.8%, and the radiographic nonunion rate was ≥13.8%. After logistic regression analysis, only the study site and peripheral neuropathy were associated with having ≥1 complication (p < .01 and p < .05, respectively). Single screw fixation compared with other fixation did not have a statistically significant influence on the postoperative complications. However, when fixation was expanded to 4 categories, single screw fixation had lower infection and reoperation rates than either crossed Kirschner wires or other fixation category but not compared with crossed screws on multivariate logistic regression analysis. Although additional studies are warranted, the findings from the present study might aid in both the prognosis of complications and the support of the use of a single screw over crossed Kirchner wire fixation in hallux interphalangeal joint arthrodesis.

  5. Malik`s Technique of Single Loop Fixation of Posterior Chamber Intraocular Lens in Presence of Partial Capsular Support

    PubMed Central

    Singh Malik, Krishan Pal; Goel, Ruchi; Kishore, Divya; Nagpal, Smriti

    2015-01-01

    Single loop fixation of posterior chamber intraocular lens in the presence of partial capsular support is usually performed by creation of additional scleral flap or tunnel. This extra port may expose the suture holding the intraocular lens or the tucked-in lens haptics to the outside environment thereby increasing the risk of endophthalmitis. We describe a technique of single loop fixation where the scleral tunnel is created adjacent to the site with the absent capsule, the leading haptic is placed on the capsular scaffold, the trailing haptic is tied to 9-0 polypropylene, and the suture is then secured to the inner edge of the scleral lip with enough tension to center the optics and the wound is then closed. The suture knot gets buried within the scleral tunnel with no external communication and does not require a separate port. It is an easy, safe, fast and reproducible technique with a lens tilt of less than 2°. PMID:26962380

  6. Technique for rapid establishment of American lotus in remediation efforts

    SciTech Connect

    Ryon, M. G.; Jett, R. T.; McCracken, M. K.; Morris, G. W.; Roy, W. K.; Fortner, A. M.; Goins, K. N.; Riazi, A. S.

    2013-03-01

    A technique for increasing the establishment rate of American lotus (Nelumbo lutea) and simplifying planting was developed as part of a pond remediation project. Lotus propagation techniques typically require scarification of the seed, germination in heated water, and planting in nursery containers. Then mature (~ 1 yr) nursery-grown stock is transferred to planting site or scarified seed are broadcast applied. Mature plants should grow more quickly, but can be sensitive to handling, require more time to plant, and cost more. Scarified seeds are easier to plant and inexpensive, but have a lag time in growth, can fail to germinate, and can be difficult to site precisely. We developed an intermediate technique using small burlap bags that makes planting easier, provides greater germination success, and avoids lag time in growth. Data on survival and growth from experiments using mature stock, scarified seeds, and bag lotus demonstrate that bag lotus grow rapidly in a variety of conditions, have a high survival rate, can be processed and planted easily and quickly, and are very suitable for a variety of remediation projects

  7. 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.

  8. Arthroscopic Labral Reconstruction of the Hip Using Iliotibial Band Allograft and Front-to-Back Fixation Technique.

    PubMed

    White, Brian J; Herzog, Mackenzie M

    2016-02-01

    Labral repair has been shown to be an effective treatment option with excellent early outcomes; however, in cases of severe labral damage or when the labral tissue is too large or diminutive, labral repair may be less effective. The purpose of this article is to present a modified technique for hip labral reconstruction using iliotibial band allograft tissue and a front-to-back fixation technique. The described technique is modified from the original report of a technique for arthroscopic labral reconstruction. The front-to-back technique allows the surgeon to make a graft that is longer than necessary and cut excess graft after front-to-back fixation, resulting in the correct graft size and a reproducible procedure. Allograft tissue offers several advantages, including the ability to control graft thickness and length, as well as the ability to eliminate donor-site morbidity. This procedure adds to the available techniques for treatment of labral pathology by providing a labral reconstruction technique using allograft tissue.

  9. Arthroscopic Labral Reconstruction of the Hip Using Iliotibial Band Allograft and Front-to-Back Fixation Technique

    PubMed Central

    White, Brian J.; Herzog, Mackenzie M.

    2016-01-01

    Labral repair has been shown to be an effective treatment option with excellent early outcomes; however, in cases of severe labral damage or when the labral tissue is too large or diminutive, labral repair may be less effective. The purpose of this article is to present a modified technique for hip labral reconstruction using iliotibial band allograft tissue and a front-to-back fixation technique. The described technique is modified from the original report of a technique for arthroscopic labral reconstruction. The front-to-back technique allows the surgeon to make a graft that is longer than necessary and cut excess graft after front-to-back fixation, resulting in the correct graft size and a reproducible procedure. Allograft tissue offers several advantages, including the ability to control graft thickness and length, as well as the ability to eliminate donor-site morbidity. This procedure adds to the available techniques for treatment of labral pathology by providing a labral reconstruction technique using allograft tissue. PMID:27073784

  10. Arthroscopic Labral Reconstruction of the Hip Using Iliotibial Band Allograft and Front-to-Back Fixation Technique.

    PubMed

    White, Brian J; Herzog, Mackenzie M

    2016-02-01

    Labral repair has been shown to be an effective treatment option with excellent early outcomes; however, in cases of severe labral damage or when the labral tissue is too large or diminutive, labral repair may be less effective. The purpose of this article is to present a modified technique for hip labral reconstruction using iliotibial band allograft tissue and a front-to-back fixation technique. The described technique is modified from the original report of a technique for arthroscopic labral reconstruction. The front-to-back technique allows the surgeon to make a graft that is longer than necessary and cut excess graft after front-to-back fixation, resulting in the correct graft size and a reproducible procedure. Allograft tissue offers several advantages, including the ability to control graft thickness and length, as well as the ability to eliminate donor-site morbidity. This procedure adds to the available techniques for treatment of labral pathology by providing a labral reconstruction technique using allograft tissue. PMID:27073784

  11. Radiological Evaluation of the Initial Fixation between Cortical Bone Trajectory and Conventional Pedicle Screw Technique for Lumbar Degenerative Spondylolisthesis

    PubMed Central

    Iwatsuki, Koichi; Ohnishi, Yu-Ichiro; Yoshimine, Toshiki

    2016-01-01

    Study Design Retrospective study. Purpose To compare initial fixation using the cortical bone trajectory (CBT) technique versus conventional pedicle screws (PS) in radiographs of postsurgical lumbar degenerative spondylolisthesis. Overview of Literature Few reports have documented the holding strength of CBT technique for spondylolisthesis cases. Methods From October 2009 to June 2014, 21 cases of degenerative spondylolisthesis were surgically treated in our institution. Ten were treated with conventional PS technique and 11 of with CBT technique. Mean lumbar lordosis and percent slippage were evaluated preoperatively, immediately after surgery, and 6 months and 1 year postoperatively using radiographs. We also investigated percent loss of slip reduction. Results There were statistically significant differences between preoperative percent slippage and postoperative slippage in both PS and CBT procedures over 1 year, and both techniques showed good slip reduction. On the other hand, lumbar lordosis did not change significantly in either the PS or CBT groups over 1 year. Conclusions CBT technique showed similarly good initial fixation compared with the PS procedure in the treatment of lumbar degenerative spondylolisthesis. PMID:27114765

  12. An Effective and Feasible Method, “Hammering Technique,” for Percutaneous Fixation of Anterior Column Acetabular Fracture

    PubMed Central

    Zhang, Lihai; Zhang, Wei; Li, Tongtong; Li, Jiantao; Chen, Hua

    2016-01-01

    Objective. The objective of this study was to evaluate the effectiveness and advantages of percutaneous fixation of anterior column acetabular fracture with “hammering technique.” Materials and Methods. We retrospectively reviewed 16 patients with percutaneous fixation of anterior column acetabular fracture with “hammering technique.” There were 11 males and 5 females with an average age of 38.88 years (range: 24–54 years) in our study. Our study included 7 nondisplaced fractures, 6 mild displaced fractures (<2 mm), and 5 displaced fractures (>2 mm). The mean time from injury to surgery was 4.5 days (range: 2–7 days). Results. The average of operation time was 27.56 minutes (range: 15–45 minutes), and the mean blood loss was 55.28 mL (range: 15–100 mL). The mean fluoroscopic time was 54.78 seconds (range: 40–77 seconds). The first pass of the guide wire was acceptable without cortical perforation or intra-articular perforation in 88.89% (16/18) of the procedures, and the second attempt was in 11.11% (2/18). Conclusion. Our study suggested that percutaneous fixation of anterior column acetabular fracture with “hammering technique” acquired satisfying surgical and clinical outcomes. It may be an alternative satisfying treatment for percutaneous fixation of anterior column acetabular fracture by 2D fluoroscopy using a C-arm with less fluoroscopic time. PMID:27493962

  13. Evaluation of a minimally invasive surgical fixation technique for young children with the Concerto Pin cochlear implant system.

    PubMed

    Schnabl, Johannes; Wolf-Magele, Astrid; Pok, Stefan Marcel; Url, Christoph; Zorowka, Patrick; Sprinzl, Georg

    2015-08-01

    In 2011, Med-El (Innsbruck, Austria) introduced a new cochlear implant system, designed to require a minimally invasive surgical technique and allow greater positional flexibility for its fixation on the skull. The Concerto Pin implant system is a good option for patients with thinner bone, such as children and elderly. The aim of this study was to investigate the implant’s stability in children using our minimally invasive surgical technique. This was a prospective, longitudinal study with a single-subject, repeated-examination design. Six children, implanted with a Concerto Pin using our minimally invasive surgical technique between October 2011 and September 2012, were assessed 1, 3 and 6 months after surgery. In each case, the implant remained in a stable position and no adverse events or problems with healing were observed at any time during the investigation. The minimally invasive technique and the method of implant fixation that bypass drilling a deep implant bed constitute a good option for patients with thinner bone, such as children. This clinical study shows the safety and stability of the Concerto Pin implant system using a minimally invasive surgical technique.

  14. Comparison between the fixation of peritoneal dialysis catheters to the peritoneal wall and the conventional placement technique: clinical experience and follow-up of a new implant technique for peritoneal dialysis catheters.

    PubMed

    Io, Hiroaki; Maeda, Kunimi; Sekiguchi, Yoshimi; Shimaoka, Tetsutaro; Aruga, Seiki; Nakata, Junichiro; Nakamoto, Hirotaka; Hotta, Yoko; Koyanagi, Ichiro; Inaba, Masanori; Kanda, Reo; Nakano, Takanori; Wakabayashi, Keiichi; Sasaki, Yuu; Inuma, Jiro; Kaneko, Kayo; Hamada, Chieko; Fukui, Mitsumine; Tomino, Yasuhiko

    2014-01-01

    Peritoneal dialysis (PD) catheters often become severely dislocated, which may lead to malfunction. With the aim of preventing this complication, we have developed a simple method of fixing the catheter downwards in the peritoneal cavity (fixation technique), a technique that does not require a laparoscope. Sixteen patients were implanted using the conventional placement technique and 25 patients were implanted using the fixation technique. The location of the catheter tip was classified from grade 1 (downward, normal) to 5 (dislocated). The frequency of dislocation (defined as the extended time and/or decrease in volume when draining the PD solution) was measured for both the fixation technique and conventional placement technique. There was a significant difference in grade between the fixation technique (2.72 ± 1.01) and conventional technique (3.92 ± 1.31). The time until first dislocation was significantly different between the fixation technique (59.3 ± 48.1 days) and conventional technique (8.8 ± 14.6 days). The time until any dislocation was significantly different between the fixation technique (69.2 ± 41.9 days) and conventional technique (12.9 ± 13.7 days). Complications were not significantly different between the fixation technique and conventional technique. The fixation technique appears to be simple, safe, and useful for preventing severe dislocation and for lengthening the time until dislocation in PD patients.

  15. Least Possible Fixation Techniques of 4-Part Valgus Impacted Fractures of the Proximal Humerus: A Systematic Review

    PubMed Central

    Panagopoulos, Andreas; Tatani, Irini; Ntourantonis, Dimitrios; Seferlis, Ioannis; Kouzelis, Antonis; Tyllianakis, Minos

    2016-01-01

    The valgus-impacted (VI) 4-part fractures are a subset of fractures of the proximal humerus with a unique anatomic configuration characterized by a relatively lower incidence of avascular necrosis after operative intervention. We systematically reviewed clinical studies assessing the benefits and harms of least possible fixation techniques (LPFT) for this unique fracture type. Such information would be potentially helpful in developing an evidence-based approach in the management of these complex injuries. We performed analytic searches of PubMed, Embase, Web of Science, Google Scholar and the Cochrane Library, restricting it to the years 1991-2014. Included studies had to describe outcomes and complications after primary osteosynthesis with any type of LPFT apart from plate-screws and intramedullary nailing. Eligibility criteria were also included English language, more than 5 cases, minimum follow up of one year and report of clinical outcome using at least one relevant score (Constant, Neer or ASES). Based on 292 database hits we identified 12 eligible studies including 190 four-part valgus impacted fractures in 188 patients. All eligible studies were case series composed of min 8 to max 45 patients per study. The gender distribution was 60% (112) female and 40% (76) male. The average age of the patients at the time of injury was 54.5 years. In 8/12 studies an open reduction was used for fracture fixation using different surgical techniques including KW, cerclage wires, cannulated screws and osteosutures. Closed reduction and percutaneous fixation was used in 4 studies. Mean follow-up time ranged from 24 to 69 months. A good functional outcome (constant score >80) was reported in 9/12 studies. The most common complication was avascular necrosis of the humeral head with an overall incidence of 11% (range, 0-26.3%). Total avascular necrosis (AVN) was found in 15/188 patients (7.9%) and was more common in percutaneous techniques and partial AVN in 6/188 (3

  16. A randomized controlled trial on cross-infection control in maxillofacial trauma surgery: a comparison of intermaxillary fixation techniques.

    PubMed

    Pigadas, N; Whitley, S P; Roberts, S A; McAlister, K; Ameerally, P; Avery, C M E

    2008-08-01

    Glove perforations and percutaneous injuries occur commonly during the treatment of facial fractures and reveal the need for safer techniques, especially in intermaxillary fixation. The Rapid IMF device does not use any wires and may provide better cross-infection control than wiring methods. The aim of this study was to test the hypothesis that Rapid IMF is associated with fewer glove perforations/ percutaneous injuries than traditional wiring techniques. The authors carried out a randomized controlled trial which included 120 patients with fractures of the mandible requiring open reduction and fixation. The participants were allocated either to the study group and treated with intraoperative Rapid IMF or to the control group and managed with intraoperative eyelet wire ties. Analysis of the results showed that the Rapid IMF group had significantly fewer glove perforations than the traditional method (0.67 per operation compared with 1.5), (P<0.0001). The incidence of skin-penetrating injuries was the same in both groups (rate 0.02/ procedure). The application of Rapid IMF was significantly faster than wiring (P<0.0001). Minor intraoperative complications were noted in both groups, but more in the Rapid IMF group. Most concerned loosening or fracture of the anchorage ties but the surgical outcome was not affected. Rapid IMF is a safer alternative to wiring methods with significant reduction in glove perforation rates and is quicker to apply than conventional wiring techniques.

  17. Coracoid bone graft osteolysis after Latarjet procedure: A comparison study between two screws standard technique vs mini-plate fixation

    PubMed Central

    Giacomo, Giovanni Di; Costantini, Alberto; de Gasperis, Nicola; De Vita, Andrea; Lin, Bernard K. H.; Francone, Marco; Beccaglia, Mario A. Rojas; Mastantuono, Marco

    2013-01-01

    Aims: One of the reason for Latarjet procedure failure may be coracoid graft osteolysis. In this study, we aimed to understand if a better compression between the coracoid process and the glenoid, using a mini-plate fixation during the Latarjet procedure, could reduce the amount of coracoid graft osteolysis. Materials and Methods: A computed tomography scan analysis of 26 prospectively followed-up patients was conducted after modified Latarjet procedure using mini-plate fixation technique to determine both the location and the amount of coracoid graft osteolysis in them. We then compared our current results with results from that of our previous study without using mini-plate fixation to determine if there is any statistical significant difference in terms of corcacoid bone graft osteolysis between the two surgical techniques. Results: The most relevant osteolysis was represented by the superficial part of the proximal coracoid, whereas the deep part of the proximal coracoid graft is least involved in osteolysis and has best bone healing. The current study showed a significant difference only for the deep part of the distal coracoid with our previous study (P < 0.01). Discussion: To our knowledge, there are no studies in literature that show the causes of coracoid bone graft osteolysis after Latarjet procedure. Conclusion: Our study suggests that there is a significant difference only for the deep part of the distal coracoid in terms of osteolysis. At clinical examination, this difference did not correspond with any clinical findings. Level of Evidence: Level 4. Clinical Relevance: Prospective case series, Treatment study. PMID:23858288

  18. A Novel Technique Using Customized Headgear for Fixation of Rigid External Distraction Device in an Infant With Crouzon Syndrome.

    PubMed

    Hariri, Firdaus; Rahman, Zainal Ariff Abdul; Mahdah, Saridah; Mathaneswaran, Vickneswaran; Ganesan, Dharmendra

    2015-11-01

    Rigid external distraction device is often indicated for superior midfacial advancement in pediatric syndromic craniosynostosis patients. Even though the technique is proven reliable to treat the functional issues related to the craniofacial deformity, major complications associated with its fixation, such as intracranial pin perforation and migration have been reported. We report a novel technique of using a customized headgear to prevent intracranial pin perforation over a very thin temporal bone region in an 8-month-old infant with Crouzon syndrome who underwent monobloc Le Fort III distraction osteogenesis using a combination of bilateral internal and a rigid external distraction device. The customized headgear provides a protective platform at the temporal region thus preventing intracranial pin perforation and allows stable fixation during the early phase of consolidation period to prevent central component relapse. The headgear can be used short term when rigid external distractor is indicated in infant patient but requires close monitoring because of risks of skin necrosis and temporal region indentation. PMID:26594993

  19. 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

  20. Immunogold electron microscopy of soluble proteins: localization of Bet v I major allergen in ultra-thin sections of birch pollen after anhydrous fixation techniques.

    PubMed

    Grote, M

    1991-10-01

    To localize the highly water-soluble major allergen Bet v I in ultra-thin sections of birch pollen, pollen grains were cracked, air-dried, and processed for electron microscopy using one of the following preparation techniques: fixation in aqueous p-formaldehyde + cetylpyridinium chloride; fixation in p-formaldehyde vapor; fixation in benzoquinone vapor; inert dehydration; or no fixation. Afterwards the pollen grains were embedded in Lowicryl K4M resin at low temperature. Ultra-thin sections were cut and incubated with a monoclonal antibody against Bet v I, followed by a gold-labeled secondary antibody. In some experiments, commercial rabbit IgG antibodies against birth pollen allergens were also used, followed by incubation with the protein A-gold complex. Bet v I could be localized only after vapor fixation and in the inert dehydrated specimens. Best preservation of ultrastructure and antigenicity was obtained after p-formaldehyde vapor fixation. Bet v I antibody binding sites were detected only in the cytoplasmic matrix of the pollen grain, never in the pollen wall. Commercial rabbit antibodies bound to cytoplasm and wall of all prepared specimens, even after aqueous fixation. This might be explained by the assumption that these antibodies recognize a variety of antigenic and allergenic structures, not all of which are so highly soluble as Bet v I.

  1. Establishment of microbial eukaryotic enrichment cultures from a chemically stratified antarctic lake and assessment of carbon fixation potential.

    PubMed

    Dolhi, Jenna M; Ketchum, Nicholas; Morgan-Kiss, Rachael M

    2012-01-01

    phototrophic and mixotrophic protists from Lake Bonney. Sampling depths in the water column were chosen based on the location of primary production maxima and protist phylogenetic diversity (4, 11), as well as variability in major abiotic factors affecting protist trophic modes: shallow sampling depths are limited for major nutrients, while deeper sampling depths are limited by light availability. In addition, lake water samples were supplemented with multiple types of growth media to promote the growth of a variety of phototrophic organisms. RubisCO catalyzes the rate limiting step in the Calvin Benson Bassham (CBB) cycle, the major pathway by which autotrophic organisms fix inorganic carbon and provide organic carbon for higher trophic levels in aquatic and terrestrial food webs (12). In this study, we applied a radioisotope assay modified for filtered samples (13) to monitor maximum carboxylase activity as a proxy for carbon fixation potential and metabolic versatility in the Lake Bonney enrichment cultures.

  2. In vitro experiments with an injection technique for cup fixation in total hip arthroplasty.

    PubMed

    Somville, J M; Moldenaers, P F; Mulier, J C; Mewis, J J

    1987-01-01

    A new technique has been developed to position the cup rigidly into the acetabulum during total hip joint replacement. After positioning the flanged cup on the acetabulum by means of screws, a low-viscosity cement is injected through a hole in the rim of the cup. A comparison with the standard cementing technique was made on the basis of in vitro experiments. For this purpose a mold was constructed to produce castings simulating the human acetabulum. The distribution of the cement, the pressure developed in the acetabulum, and the penetration of the cement are compared for the two cementing techniques. PMID:3606358

  3. Biomechanical Evaluation of Interfragmentary Compression At Tibia Plateau Fractures In Vitro Using Different Fixation Techniques: A CONSORT-Compliant Article: Erratum.

    PubMed

    2015-02-01

    [In the article "Biomechanical Evaluation of Interfragmentary Compression At Tibia Plateau Fractures In Vitro Using Different Fixation Techniques: A CONSORT-compliant" article, which appeared in Volume 94, Issue 1 of Medicine, a line denoting dual authorship was omitted. K. Kojima and B. Gueorguiev contributed equally to the article.].

  4. A modified surgical technique for lengthening of a metatarsal using an external fixator.

    PubMed

    Scher, David M; Blyakher, Arkady; Krantzow, Michael

    2010-09-01

    Brachymetatarsia is a congenital or developmental condition that results in a short metatarsal. Problems that arise from this condition can include pain, difficulty with shoe wear, and cosmetic concerns. Multiple techniques have been described that successfully correct the deformity, including both acute and gradual distraction. We describe a modification of the technique of gradual lengthening by way of distraction osteogenesis in which an axial transarticular K-wire is incorporated into a monolateral frame, thereby increasing the stability of the construct and potentially minimizing complications. PMID:21886542

  5. A Modified Surgical Technique for Lengthening of a Metatarsal Using an External Fixator

    PubMed Central

    Blyakher, Arkady; Krantzow, Michael

    2010-01-01

    Brachymetatarsia is a congenital or developmental condition that results in a short metatarsal. Problems that arise from this condition can include pain, difficulty with shoe wear, and cosmetic concerns. Multiple techniques have been described that successfully correct the deformity, including both acute and gradual distraction. We describe a modification of the technique of gradual lengthening by way of distraction osteogenesis in which an axial transarticular K-wire is incorporated into a monolateral frame, thereby increasing the stability of the construct and potentially minimizing complications. PMID:21886542

  6. In vitro biomechanical evaluation of internal fixation techniques on the canine lumbosacral junction

    PubMed Central

    Dillard, Stacy; Roe, Simon

    2015-01-01

    Few biomechanical studies have evaluated the effect of internal stabilization techniques after decompressive surgery on the stability of the canine lumbosacral junction. The purpose of this canine cadaver study is to evaluate the stability of the canine lumbosacral (LS) spine in flexion and extension following laminectomy and discectomy and then stabilization with each of the three techniques: pins and polymethylmethacrylate (P/PMMA), two dorsal locking plates (SOP) or bilateral transarticular facet screws (FACET).Using a cantilever biomechanical system, bending moments were applied to the LS and range of motion (ROM) was recorded via a rotational potentiometer. With 3 Nm, the ROM (n = 4 in each group) for P/PMMA, SOP and FACET were 1.92 ± 0.96°, 2.56 ± 0.55°and 3.18 ± 1.14°, respectively. With moments up to 35 Nm, the P/PMMA specimens appeared stable. Sacroiliac motion in the SOP and FACET groups invalidated further comparisons. Each of the stabilization techniques (P/PMMA, SOP, and FACET) significantly decreased the range of motion in flexion and extension for low bending moments. PMID:26312169

  7. A comparative study of pedicle screw fixation in dorsolumbar spine by freehand versus image-assisted technique: A cadaveric study

    PubMed Central

    Agarwal, Archit; Chauhan, Vijendra; Singh, Deepa; Shailendra, Raghuvanshi; Maheshwari, Rajesh; Juyal, Anil

    2016-01-01

    Background: New and expensive technology such as three-dimensional computer assisted surgery is being used for pedicle screw fixation in dorsolumbar spine. Their availability, expenses and amount of radiation exposure are issues in a developing country. On the contrary, freehand technique of pedicle screw placement utilizes anatomic landmarks and tactile palpation without fluoroscopy or navigation to place pedicle screws. The purpose of this study was to analyze and compare the accuracy of freehand and image-assisted technique to place pedicle screws in the dorsolumbar spine of cadavers by an experienced surgeon and a resident. Evaluation was done using dissection of pedicle and computed tomography (CT) imaging. Materials and Methods: Ten cadaveric dorsolumbar spines were exposed by a posterior approach. Titanium pedicle screws were inserted from D5 to L5 vertebrae by freehand and image-assisted technique on either side by an experienced surgeon and a resident. CT was obtained. A blinded radiologist reviewed the imaging. The spines were then dissected to do a macroscopic examination. Screws, having evidence of cortical perforation of more than 2 mm on CT, were considered to be a significant breach. Results: A total of 260 pedicle screws were placed. The surgeon and the resident placed 130 screws each. Out of 130 screws, both of them placed 65 screws each by freehand and image- assisted technique each. The resident had a rate of 7.69% significant medial and 10.76% significant lateral breach with freehand technique while with image-assisted had a rate of 3.07% significant medial and 9.23% significant lateral breach. The expert surgeon had a rate of 6.15% significant medial and 1.53% significant lateral breach with freehand technique while with image-assisted had a rate of 3.07% significant medial and 6.15% significant lateral breach on CT evaluation. Conclusion: Freehand technique is as good as the image-assisted technique. Under appropriate supervision, residents

  8. Miniarthrotomy assisted percutaneous screw fixation for displaced medial malleolus fractures – A novel technique

    PubMed Central

    Saini, Pramod; Aggrawal, Abhinav; Meena, Sanjay; Trikha, Vivek; Mittal, Samarth

    2014-01-01

    Aim To describe here a technique of miniarthrotomy assisted percutaneous screw insertion for displaced Herscovici type B and C medial malleolar fractures. Method Incision was made centred over the superomedial angle of the ankle mortise, about half a cm medial to tibialis anterior. Arthrotomy was done and reduction obtained. Percuntaneously, two 4 mm cancellous cannulated screws were inserted through medial malleolus. Results and conclusion This approach allows direct visualization of reduction, removal of entrapped soft tissue and preservation of saphenous vein and nerve. PMID:25983507

  9. A freeze substitution fixation-based gold enlarging technique for EM studies of endocytosed Nanogold-labeled molecules.

    PubMed

    He, Wanzhong; Kivork, Christine; Machinani, Suman; Morphew, Mary K; Gail, Anna M; Tesar, Devin B; Tiangco, Noreen E; McIntosh, J Richard; Bjorkman, Pamela J

    2007-10-01

    We have developed methods to locate individual ligands that can be used for electron microscopy studies of dynamic events during endocytosis and subsequent intracellular trafficking. The methods are based on enlargement of 1.4 nm Nanogold attached to an endocytosed ligand. Nanogold, a small label that does not induce misdirection of ligand-receptor complexes, is ideal for labeling ligands endocytosed by live cells, but is too small to be routinely located in cells by electron microscopy. Traditional pre-embedding enhancement protocols to enlarge Nanogold are not compatible with high pressure freezing/freeze substitution fixation (HPF/FSF), the most accurate method to preserve ultrastructure and dynamic events during trafficking. We have developed an improved enhancement procedure for chemically fixed samples that reduced auto-nucleation, and a new pre-embedding gold enlarging technique for HPF/FSF samples that preserved contrast and ultrastructure and can be used for high-resolution tomography. We evaluated our methods using labeled Fc as a ligand for the neonatal Fc receptor. Attachment of Nanogold to Fc did not interfere with receptor binding or uptake, and gold-labeled Fc could be specifically enlarged to allow identification in 2D projections and in tomograms. These methods should be broadly applicable to many endocytosis and transcytosis studies.

  10. Arthroscopic technique for fragment fixation using absorbable pins for osteochondritis dissecans of the humeral capitellum: a report of 4 cases.

    PubMed

    Takeba, Jun; Takahashi, Toshiaki; Hino, Kazunori; Watanabe, Seiji; Imai, Hiroshi; Yamamoto, Haruyasu

    2010-06-01

    This is the first report to describe a method of arthroscopic osteochondral fixation using absorbable pins to treat osteochondritis dissecans (OCD) of the capitellum. Four adolescent baseball players with OCD of the capitellum were treated, and good short-term results were obtained. During this arthroscopic procedure, the elbow was maintained in the maximum flexed position, and posterolateral portals were used to visualize the lesion, perform drilling, and insert the pins. This procedure is less invasive and easier to perform than other fixation procedures that require harvesting or production of autologous bone pegs. This is an effective method of fragment fixation with absorbable pins.

  11. The Mechanics of External Fixation

    PubMed Central

    Rozbruch, S. Robert

    2006-01-01

    External fixation has evolved from being used primarily as a last resort fixation method to becoming a main stream technique used to treat a myriad of bone and soft tissue pathologies. Techniques in limb reconstruction continue to advance largely as a result of the use of these external devices. A thorough understanding of the biomechanical principles of external fixation is useful for all orthopedic surgeons as most will have to occasionally mount a fixator throughout their career. In this review, various types of external fixators and their common clinical applications are described with a focus on unilateral and circular frames. The biomechanical principles that govern bony and fixator stability are reviewed as well as the recommended techniques for applying external fixators to maximize stability. Additionally, we have illustrated methods for managing patients while they are in the external frames to facilitate function and shorten treatment duration. PMID:18751766

  12. CT-based morphometric analysis of C1 laminar dimensions: C1 translaminar screw fixation is a feasible technique for salvage of atlantoaxial fusions

    PubMed Central

    Yew, Andrew; Lu, Derek; Lu, Daniel C.

    2015-01-01

    Background: Translaminar screw fixation has become an alternative in the fixation of the axial and subaxial cervical spine. We report utilization of this approach in the atlas as a salvage technique for atlantoaxial stabilization when C1 lateral mass screws are precluded. To assess the feasibility of translaminar fixation at the atlas, we have characterized the dimensions of the C1 lamina in the general adult population using computed tomography (CT)-based morphometry. Methods: A 46-year-old male with symptomatic atlantoaxial instability secondary to os odontoideum underwent bilateral C1 and C2 translaminar screw/rod fixation as C1 lateral mass fixation was precluded by an anomalous vertebral artery. The follow-up evaluation 2½ years postoperatively revealed an asymptomatic patient without recurrent neck/shoulder pain or clinical signs of instability. To better assess the feasibility of utilizing this approach in the general population, we retrospectively analyzed 502 consecutive cervical CT scans performed over a 3-month period in patients aged over 18 years at a single institution. Measurements of C1 bicortical diameter, bilateral laminar length, height, and angulation were performed. Laminar and screw dimensions were compared to assess instrumentation feasibility. Results: Review of CT imaging found that 75.9% of C1 lamina had a sufficient bicortical diameter, and 63.7% of C1 lamina had sufficient height to accept bilateral translaminar screw placement. Conclusions: CT-based measurement of atlas morphology in the general population revealed that a majority of C1 lamina had sufficient dimensions to accept translaminar screw placement. Although these screws appear to be a feasible alternative when lateral mass screws are precluded, further research is required to determine if they provide comparable fixation strength versus traditional instrumentation methods. PMID:26005585

  13. 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

  14. New Technique for C1 Double-Door Laminoplasty Using Allograft Spacers and Titanium Miniplate Screw Fixation: Technical Report.

    PubMed

    Kim, Seok Woo; Lee, Jae-Hoo; Lee, Ho-Won; Oh, Jae-Keun; Kwak, Yoon-Hae

    2016-03-01

    Although conventional C1 laminectomy is the gold standard for decompression at the atlas, it provides little space for the bone graft to fuse. The fusion area can be extended cranially up to the occipital bone, but it requires sacrificing the function of the craniocervical junction. To date, no reports have focused on surgical techniques for successful decompression and fusion without disruption of the posterior C1 arch while providing enough room for the bone graft to fuse. This study introduces a new technique for C1-C2 fusion and C1 double-door laminoplasty in patients with C1-C2 instability, canal stenosis, and cervical spondylotic myelopathy. A 66-year-old man who had undergone C1-C2 fusion at a local clinic 2 years earlier visited our hospital due to progressive myelopathy. A preoperative computed tomography (CT) scan showed the tip of the odontoid process, extending into the spinal canal. On the axial view of T2-weighted magnetic resonance images, the tip of the odontoid process significantly compressed the spinal cord on the left side. The atlantodental interval was 7 mm on radiography; however, C1-C2 instability was not evident on flexion-extension X-rays due to the previous screw fixation. The patient underwent C1-C2 decompression and fusion surgery with our new surgical technique. The segmental screws were repositioned at C1 and C2, and we performed C1 double-door laminoplasty augmented with an allograft spacer and a titanium miniplate. A marked reduction was seen at postoperative radiograph and CT scan. Neurologic symptoms were relieved dramatically after surgery without any discomfort. No complications were noted. We introduced a new surgical technique that allows bone grafting, decompression, and fusion to be performed without disruption of the posterior C1 arch in the event of C1-C2 canal stenosis combined with instability. This technique may be indicated for other conditions that cause instability and stenosis at the C1-C2 area. PMID:26689563

  15. A simple osmium post-fixation paraffin-embedment technique to identify lipid accumulation in fish liver using medaka (Oryziaslatipes) eggs and eleutheroembryos as lipid rich models.

    PubMed

    Mondon, J A; Howitt, J; Tosiano, M; Kwok, K W H; Hinton, D E

    2011-01-01

    Hepatic lipidosis is a non-specific biomarker of effect from pollution exposure in fish. Fatty liver is often misdiagnosed or overlooked in histological assessments due to the decreasing application of specific fat procedures and stains. For example, ethanol dehydration in standard paraffin processing removes lipids, leaving vacuoles of which the precise nature is unknown. Lipids can be identified using osmium post-fixation in semi-thin resin sections or transmission electron microscopy. However, both are expensive and technically demanding procedures, often not available for routine environmental risk assessment and monitoring programs. The current emphasis to reduce and refine animal toxicity testing, requires refinement of the suite of histopathological techniques currently available to maximize information gained from using fish for toxicity testing and as bio-indicators of environmental quality. This investigation has successfully modified an osmium post-fixation technique to conserve lipids in paraffin-embedded tissues using medaka (Oryzias latipes) eleutheroembryos and eggs (embryos) as lipid rich models.

  16. 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.

  17. Coral surface area quantification-evaluation of established techniques by comparison with computer tomography

    NASA Astrophysics Data System (ADS)

    Naumann, M. S.; Niggl, W.; Laforsch, C.; Glaser, C.; Wild, C.

    2009-03-01

    The surface area of scleractinian corals represents an important reference parameter required for various aspects of coral reef science. However, with advancements in detection accuracy and novel approaches for coral surface area quantification, evaluation of established techniques in comparison with state-of-the-art technology gains importance to coral researchers. This study presents an evaluation of methodological accuracy for established techniques in comparison to a novel approach composed of computer tomography (CT) and 3-dimensional surface reconstruction. The skeleton surface area of reef corals from six genera representing the most common morphological growth forms was acquired by CT and subsequently measured by computer-aided 3-dimensional surface reconstruction. Surface area estimates for the same corals were also obtained by application of four established techniques: Simple and Advanced Geometry, Wax Coating and Planar Projection Photography. Comparison of the resulting area values revealed significant differences between the majority (82%) of established techniques and the CT reference. Genus-specific analysis assigned the highest accuracy to geometric approximations (Simple or Advanced Geometry) for the majority of assessed coral genera (maximum accuracy: 104%; Simple Geometry with Montipora sp.). The commonly used and invasive Wax Coating technique reached intermediate accuracy (47-74%) for the majority of genera, but performed outstanding in the measurement of branching Acropora spp. corals (maximum accuracy: 101%), while the Planar Projection Photography delivered genera-wide low accuracy (12-36%). Comparison of area values derived from established techniques and CT additionally yielded approximation factors (AFs) applicable as factors in the mathematical improvement of surface area estimates by established techniques in relation to CT reference accuracy.

  18. Symbiotic N2-Fixation Estimated by the 15N Tracer Technique and Growth of Pueraria phaseoloides (Roxb.) Benth. Inoculated with Bradyrhizobium Strain in Field Conditions

    PubMed Central

    Sarr, Papa Saliou; Okon, Judith Wase; Begoude, Didier Aime Boyogueno; Araki, Shigeru; Ambang, Zachée; Shibata, Makoto; Funakawa, Shinya

    2016-01-01

    This field experiment was established in Eastern Cameroon to examine the effect of selected rhizobial inoculation on N2-fixation and growth of Pueraria phaseoloides. Treatments consisted of noninoculated and Bradyrhizobium yuanmingense S3-4-inoculated Pueraria with three replications each. Ipomoea batatas as a non-N2-fixing reference was interspersed in each Pueraria plot. All the twelve plots received 2 gN/m2 of 15N ammonium sulfate 10% atom excess. At harvest, dry matter yields and the nitrogen derived from atmospheric N2-fixation (%Ndfa) of inoculated Pueraria were significantly (P < 0.05) higher (81% and 10.83%, resp.) than those of noninoculated Pueraria. The inoculation enhanced nodule dry weight 2.44-fold. Consequently, the harvested N significantly (P < 0.05) increased by 83% in inoculated Pueraria, resulting from the increase in N2-fixation and soil N uptake. A loss of 55 to 60% of the N fertilizer was reported, and 36 to 40% of it was immobilized in soil. Here, we demonstrated that both N2-fixing potential of P. phaseoloides and soil N uptake are improved through field inoculations using efficient bradyrhizobial species. In practice, the inoculation contributes to maximize N input in soils by the cover crop's biomass and represent a good strategy to improve soil fertility for subsequent cultivation. PMID:26904363

  19. Symbiotic N 2 -Fixation Estimated by the (15) N Tracer Technique and Growth of Pueraria phaseoloides (Roxb.) Benth. Inoculated with Bradyrhizobium Strain in Field Conditions.

    PubMed

    Sarr, Papa Saliou; Okon, Judith Wase; Begoude, Didier Aime Boyogueno; Araki, Shigeru; Ambang, Zachée; Shibata, Makoto; Funakawa, Shinya

    2016-01-01

    This field experiment was established in Eastern Cameroon to examine the effect of selected rhizobial inoculation on N2-fixation and growth of Pueraria phaseoloides. Treatments consisted of noninoculated and Bradyrhizobium yuanmingense S3-4-inoculated Pueraria with three replications each. Ipomoea batatas as a non-N2-fixing reference was interspersed in each Pueraria plot. All the twelve plots received 2 gN/m(2) of (15)N ammonium sulfate 10% atom excess. At harvest, dry matter yields and the nitrogen derived from atmospheric N2-fixation (%Ndfa) of inoculated Pueraria were significantly (P < 0.05) higher (81% and 10.83%, resp.) than those of noninoculated Pueraria. The inoculation enhanced nodule dry weight 2.44-fold. Consequently, the harvested N significantly (P < 0.05) increased by 83% in inoculated Pueraria, resulting from the increase in N2-fixation and soil N uptake. A loss of 55 to 60% of the N fertilizer was reported, and 36 to 40% of it was immobilized in soil. Here, we demonstrated that both N2-fixing potential of P. phaseoloides and soil N uptake are improved through field inoculations using efficient bradyrhizobial species. In practice, the inoculation contributes to maximize N input in soils by the cover crop's biomass and represent a good strategy to improve soil fertility for subsequent cultivation. PMID:26904363

  20. [Underlying mechanisms and related techniques of stand establishment of cotton on coastal saline-alkali soil].

    PubMed

    Dong, He-Zhong

    2012-02-01

    Stand establishment is the most difficult step for cotton planting on coastal saline-alkali soil. To establish and improve the techniques for stand establishment is the key in the production of high-yielding cotton on saline-alkali soil. Based on the previous studies and our own research progress in this field, this paper reviewed the effects and the underlying mechanisms of making unequal salt distribution in root zone, increasing soil moisture and temperature, establishing under-mulching greenhouse, and introducing seed coating agent in promoting stand establishment of cotton on saline-alkali soil. It was suggested that under the conditions of the average salt content in topsoil being not able to reduce, improving at least partial root zone environment through the induction of unequal salt distribution in the root zone and increasing soil moisture and temperature could significantly reduce salt injury and improve stand establishment. Flat seeding under plastic mulching on low-salinity soil, furrow seeding with mulching on moderate- or high-salinity soil, early mulching before sowing on rain-fed saline soil, and late sowing of short-season cotton in heat-limited area were the efficient techniques for improving the stand establishment of cotton on coastal saline-alkali soil. This review could provide full guarantee for the cotton stand establishment on coastal saline-alkali soil.

  1. Percutaneous Facet Screw Fixation in the Treatment of Symptomatic Recurrent Lumbar Facet Joint Cyst: A New Technique.

    PubMed

    Amoretti, Nicolas; Gallo, Giacomo; Bertrand, Anne-Sophie; Bard, Robert L; Kelekis, Alexis

    2016-01-01

    We present a case of percutaneous treatment of symptomatic recurrent lumbar facet joint cyst resistant to all medical treatments including facet joint steroid injection. Percutaneous transfacet fixation was then performed at L4-L5 level with a cannulated screw using CT and fluoroscopy guidance. The procedure time was 30 min. Using the visual analog scale (VAS), pain decreased from 9.5, preoperatively, to 0 after the procedure. At 6-month follow-up, an asymptomatic cystic recurrence was observed, which further reduced at the 1-year follow-up. Pain remained stable (VAS at 0) during all follow-ups. CT- and fluoroscopy-guided percutaneous cyst rupture associated with facet screw fixation could be an alternative to surgery in patients suffering from a symptomatic recurrent lumbar facet joint cyst.

  2. Methods and procedures for use of complement-fixation technique in type- and strain-specific diagnosis of influenza*†

    PubMed Central

    Lief, Florence S.; Henle, Werner

    1959-01-01

    It is now well established that there are two kinds of complement-fixing antigens of influenza virus: the soluble, type-specific, antigens, found mainly in infected tissue but also within the virus particle; and the virus, strain-specific, antigens, closely linked with the haemagglutinating component. For true results in complement-fixation testing in influenza, antigens or antisera of the one kind must be free of the other kind. This paper describes in detail the preparation of reagents for such testing and a variety of basic aspects of test procedures. PMID:13651922

  3. Biomechanical Evaluation of Supplemental Percutaneous Lumbo-Sacro-iliac Screws For Spino-pelvic Fixation Following Total Sacrectomy

    PubMed Central

    Le, Vu H.; Heckmann, Nathanael; Jain, Nickul; Wang, Lawrence; Turner, Alexander W. L.; Lee, Thay Q.; Bederman, S. Samuel

    2015-01-01

    Study Design This is a cadaveric biomechanical study evaluating the biomechanical properties of a novel spino-pelvic fixation technique with percutaneous lumbo-sacro-iliac (LSI) screws in an unstable total sacrectomy model. Objective To compare standard posterior dual rod spino-pelvic fixation alone with dual rod fixation supplemented with LSI screw fixation. Summary of Background Data Primary or metastatic tumors of the sacrum requiring a total sacrectomy can result in spino-pelvic instability if inadequate fixation is achieved. Many fixation techniques have been proposed to address this instability. However, to date, an optimal fixation technique has not been established. Methods Ten fresh-frozen cadaveric spino-pelvic specimens were randomized according to bone mineral density (BMD) to either posterior rod fixation (control group) or posterior rod fixation with supplemental LSI screws (LSI group). Following fixation, a total sacrectomy of each specimen was performed. Specimens where then potted and axially loaded in a caudal direction. Stiffness, yield load, energy absorbed at yield load, ultimate load, and energy absorbed at ultimate load were computed. A students t-test was used for statistical analysis with significance set at p<0.05. Results The average age and BMD were not significantly different between the control and LSI groups (age, p=0.255; BMD, p=0.810). After normalizing for BMD, there were no significant differences detected for any of the biomechanical parameters measured between the two fixation techniques: stiffness (p=0.857), yield load (p=0.219), energy at yield load (p=0.293), ultimate load (p=0.407), and energy at ultimate load (p=0.773). However, both fixation techniques were able to withstand physiological loads. Conclusions Our study did not demonstrate any biomechanical advantage for supplemental LSI screw fixation in our axial loading model. However, given the theoretical advantage of this percutaneous technique, further studies are

  4. A Simple Technique for the Positioning of a Patient with an above Knee Amputation for an Ipsilateral Extracapsular Hip Fracture Fixation

    PubMed Central

    Davarinos, N.; Ellanti, P.; McCoy, G.

    2013-01-01

    The positioning of the patient on the fracture table is critical to the successful reduction and operative fixation of hip fractures which are fixed using the dynamic hip screw system (DHS). There is a standard setup which is commonly used with relative ease. Yet the positioning of patients with amputations either above or below knee of the affected side can pose a significant challenge. We describe a novel positioning technique used on a 51-year old patient with a right above knee amputation who sustained an intertrochanteric extracapsular hip fracture. PMID:24416607

  5. Development of an automation technique for the establishment of functional lipid bilayer arrays

    NASA Astrophysics Data System (ADS)

    Hansen, J. S.; Perry, M.; Vogel, J.; Vissing, T.; Hansen, C. R.; Geschke, O.; Emnéus, J.; Nielsen, C. H.

    2009-02-01

    In the present work, a technique for establishing multiple black lipid membranes (BLMs) in arrays of micro structured ethylene tetrafluoroethylene (ETFE) films, and supported by a micro porous material was developed. Rectangular 8 × 8 arrays with apertures having diameters of 301 ± 5 µm were fabricated in ETFE Teflon film by laser ablation using a carbon dioxide laser. Multiple lipid membranes could be formed across the micro structured 8 × 8 array ETFE partitions. Success rates for the establishment of cellulose-supported BLMs across the multiple aperture arrays were above 95%. However, the time course of the membrane thinning process was found to vary considerably between multiple aperture bilayer experiments. An airbrush partition pretreatment technique was developed to increase the reproducibility of the multiple lipid bilayers formation during the time course from the establishment of the lipid membranes to the formation of bilayers. The results showed that multiple lipid bilayers could be reproducible formed across the airbrush-pretreated 8 × 8 rectangular arrays. The ionophoric peptide valinomycin was incorporated into established membrane arrays, resulting in ionic currents that could be effectively blocked by tetraethylammonium. This shows that functional bimolecular lipid membranes were established, and furthermore outlines that the established lipid membrane arrays could host functional membrane-spanning molecules.

  6. A Challenging Case of Limb Salvage Requiring a Combination of Composite Fixation and Masquelet Technique to Address Significant Segmental Bone Loss

    PubMed Central

    Blair, C.; Simela, A. T.; Cross, B. J.

    2015-01-01

    Cases of limb salvage following skeletal trauma involving significant bone loss pose a particular challenge to the reconstructive surgeon. Certain techniques for addressing this complex issue have been advanced in recent years and have met with considerable success. The Masquelet technique involves a staged procedure in which a temporary skeletal stabilization is paired with implantation of an antibiotic spacer and left in place for 6–8 weeks, during which time a “pseudomembrane” forms around the cement spacer. During the second stage of the procedure, the pseudomembrane is incised, the antibiotic spacer removed, and bone graft is placed. We present a case of significant segmental femur loss in a 19-year-old male opting for limb salvage in which a 17-centimeter segmental loss of bone was essentially regrown using a combination of the Masquelet technique with supplemental endosteal fixation. PMID:25789190

  7. Novel labeling technique illustrates transfer of 15N2 from Sphagnum moss to vascular plants via diazotrophic nitrogen fixation

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    We used 15N2 gas to trace nitrogen (N) from biological N2-fixation to vascular plant uptake in an Alberta bog in order to determine if neighboring bog plants acquire recently fixed N from diazotrophs associating with Sphagnum mosses. Recent evidence indicates high rates of N2-fixation in Sphagnum mosses of Alberta bogs (Vile et al. 2013). Our previous work has shown that mosses can assimilate fixed N from associated diazotrophs as evidenced by the high N content of mosses despite minimal inputs from atmospheric deposition, retranslocation, and N mineralization. Therefore, the potential exists for vascular plants to obtain N from ';leaky' tissues of live mosses, however, this phenomenon has not been tested previously. Here we document the potential for relatively rapid transfer to vascular plants of N fixed by Sphagnum moss-associated diazotrophs. We utilized the novel approach of incubating mosses in 15N2 to allow the process of diazotrophic N2-fixation to mechanistically provide the 15N label, which is subsequently transferred to Sphagnum mosses. The potential for vascular bog natives to tap this N was assessed by planting the vascular plants in the labeled moss. Sphagnum mosses (upper 3 cm of live plants) were incubated in the presence of 98 atom % 15N2 gas for 48 hours. Two vascular plants common to Alberta bogs; Picea mariana and Vaccinium oxycoccus were then placed in the labeled mosses, where the mosses served as the substrate. Tissue samples from these plants were collected at three time points during the incubation; prior to 15N2 exposure (to determine natural abundance 15N), and at one and two months after 15N2 exposure. Roots and leaves were separated and run separately on a mass spectrometer to determine 15N concentrations. Sphagnum moss capitula obtained N from N2-fixation (δ15N of -2.43 × 0.40, 122.76 × 23.78, 224.92 × 68.37, 143.74 × 54.38 prior to, immediately after, and at 1 and 2 months after exposure to 15N2, respectively). Nitrogen was

  8. Fixation techniques for the anterior cruciate ligament reconstruction: early follow-up. A systematic review of level I and II therapeutic studies.

    PubMed

    Speziali, Andrea; Delcogliano, Marco; Tei, Matteo; Placella, Giacomo; Bartoli, Matteo; Menghi, Amerigo; Cerulli, Giuliano

    2014-12-01

    The purpose of our study was that to systematically review the fixation techniques for the ACL reconstruction and associated clinical outcomes at the early follow-up. Systematic search on three electronic databases (Cochrane register, Medline and Embase) of fixation devices used for primary ACL reconstruction with doubled semitendinosus and gracilis and bone-patellar tendon-bone autografts in randomized clinical trials of level I and II of evidence published from January 2001 to December 2011. Therapeutic studies collected were with a minimum 12-month follow-up, and the clinical outcomes were evaluated by at least one of International Knee Documentation Committee, Lysholm and Tegner functional scales and at least one of the following knee stability tests: arthrometric AP tibial translation, Lachman test and pivot-shift test. Nineteen articles met the inclusion criteria. At the femoral side cross-pin, metallic interference screw, bioabsorbable interference screw, and suspensory device were used in 32.3, 27.3, 24.8, 15.5% of patients, respectively. At the tibial side fixation was achieved with metallic interference screw, bioabsorbable interference screw, screw and plastic sheath, screw post and cross-pin in 38.7, 31, 15.7, 12.8, and 1.7% of patients, respectively. Side-to-side anterior-posterior tibial translation was 1.9 ± 0.9, 1.5 ± 0.9, 1.5 ± 0.8, 2.2 ± 0.4 mm for metallic interference screw, bioabsorbable screw, cross-pin and suspensory device, respectively. At least two-third of all the patients achieved good-to-excellent clinical outcomes. Rate of failure was 6.1, 3.3, 1.7 and 1.2% for bioabsorbable interference screw, metallic interference screw, cross-pin and suspensory device, respectively. Clinical outcomes are good to excellent in almost two-third of the patients but several pitfalls that affect the current fixation techniques as graft tensioning such as graft-tunnel motion are still unaddressed. PMID:25269758

  9. Comparison of Surgical Outcomes Between Short-Segment Open and Percutaneous Pedicle Screw Fixation Techniques for Thoracolumbar Fractures.

    PubMed

    Fu, Zhiguo; Zhang, Xi; Shi, Yaohua; Dong, Qirong

    2016-01-01

    BACKGROUND This study aimed to compare the surgical outcomes between open pedicle screw fixation (OPSF) and percutaneous pedicle screw fixation (PPSF) for the treatment of thoracolumbar fractures, which has received scant research attention to date. MATERIAL AND METHODS Eight-four patients with acute and subacute thoracolumbar fractures who were treated with SSPSF from January 2013 to June 2014 at the Changzhou Hospital of Traditional Chinese Medicine (Changzhou, China) were retrospectively reviewed. The patients were divided into 4 groups: the OPSF with 4 basic screws (OPSF-4) group, the OPSF with 4 basic and 2 additional screws (OPSF-6) group, the PPSF with 4 basic screws (PPSF-4) group, and the PPSF with 4 basic and 2 additional screws (PPSF-6) group. The intraoperative, immediate postoperative, and over 1-year follow-up outcomes were evaluated and compared among these groups. RESULTS Blood loss in the PPSF-4 group and the PPSF-6 group was significantly less than in the OPSF-4 group and the OPSF-6 group (P<0.05). The OPSF-6 group exhibited significantly higher immediate postoperative correction percentage of anterior column height of fractured vertebra than the other 3 groups (P<0.05), and higher correction of sagittal regional Cobb angle and kyphotic angle of injured vertebra than in the PPSF-4 and -6 groups (P<0.05). In addition, there was no significant difference in the correction loss of percentage of anterior column height, and loss of sagittal Cobb angle and kyphotic angle of fractured vertebrae at final follow-up among the 4 groups (P>0.05). CONCLUSIONS OPSF with 6 screws had an advantage in the correction of injured vertebral height and kyphosis, and PPSF reduced the intraoperative blood loss of patients. PMID:27602557

  10. Comparison of Surgical Outcomes Between Short-Segment Open and Percutaneous Pedicle Screw Fixation Techniques for Thoracolumbar Fractures

    PubMed Central

    Fu, Zhiguo; Zhang, Xi; Shi, Yaohua; Dong, Qirong

    2016-01-01

    Background This study aimed to compare the surgical outcomes between open pedicle screw fixation (OPSF) and percutaneous pedicle screw fixation (PPSF) for the treatment of thoracolumbar fractures, which has received scant research attention to date. Material/Methods Eight-four patients with acute and subacute thoracolumbar fractures who were treated with SSPSF from January 2013 to June 2014 at the Changzhou Hospital of Traditional Chinese Medicine (Changzhou, China) were retrospectively reviewed. The patients were divided into 4 groups: the OPSF with 4 basic screws (OPSF-4) group, the OPSF with 4 basic and 2 additional screws (OPSF-6) group, the PPSF with 4 basic screws (PPSF-4) group, and the PPSF with 4 basic and 2 additional screws (PPSF-6) group. The intraoperative, immediate postoperative, and over 1-year follow-up outcomes were evaluated and compared among these groups. Results Blood loss in the PPSF-4 group and the PPSF-6 group was significantly less than in the OPSF-4 group and the OPSF-6 group (P<0.05). The OPSF-6 group exhibited significantly higher immediate postoperative correction percentage of anterior column height of fractured vertebra than the other 3 groups (P<0.05), and higher correction of sagittal regional Cobb angle and kyphotic angle of injured vertebra than in the PPSF-4 and -6 groups (P<0.05). In addition, there was no significant difference in the correction loss of percentage of anterior column height, and loss of sagittal Cobb angle and kyphotic angle of fractured vertebrae at final follow-up among the 4 groups (P>0.05). Conclusions OPSF with 6 screws had an advantage in the correction of injured vertebral height and kyphosis, and PPSF reduced the intraoperative blood loss of patients. PMID:27602557

  11. Multiplane transesophageal echocardiographic acquisition of ascending aortic flow velocities: A comparison with established techniques.

    PubMed

    Harris, S N; Luther, M A; Perrino, A C

    1999-09-01

    Acquisition of ascending aortic flow velocities with monoplane transesophageal echocardiography (TEE) have been problematic because of limitations of available imaging planes and alignment of the Doppler beam with aortic flow. The rotatable imaging array of multiplane TEE (Multi TEE) may provide improved alignment with ascending aortic blood flow. The purpose of this study was to establish the validity of maximal aortic flow velocities (VMax) and velocity time integrals (VTI) obtained by a Multi TEE continuous wave Doppler technique by comparison with those obtained by established echocardiographic techniques, suprasternal Doppler (SSD), and monoplane TEE (Mono TEE). Forty-five patients scheduled for elective surgery were prospectively studied. Multi TEE-obtained VMax and VTI were significantly greater (P <.05), 120 +/- 28.9 cm/s and 25.8 +/- 7 cm, than those obtained by the SSD method, 100.2 +/- 28.6 cm/s and 19.8 +/- 6.8 cm, respectively. Bias analysis revealed that Multi TEE better assessed VMax (mean difference -19.7, SD of the difference of 28 cm/s) and VTI (mean difference -5.9, SD of the difference of 6.4 cm) than the SSD method. Multi TEE exhibited values for VMax 10% or greater than those obtained by SSD in 18 (48. 6%) of 37 patients, and Multi TEE was 10% or greater than SSD in 23 (67%) of 37 patients for VTI determination. Values obtained by Multi TEE and Mono TEE showed close agreement. Multi TEE provides a favorable alignment for continuous wave Doppler interrogation of aortic flow and compared favorably to established techniques. This technique expands the utility of TEE to evaluate aortic valvular function and cardiac performance.

  12. Establishment of C6 brain glioma models through stereotactic technique for laser interstitial thermotherapy research

    PubMed Central

    Shi, Jian; Zhang, Ying; Fu, Wei-ming; Chen, Minjiang; Qiu, Zheng

    2015-01-01

    Objective: To establish C6 brain glioma models using stereotactic technique, and to study effects of laser interstitial thermotherapy (LITT) in rat models of glioma. Methods: C6 glioma cells were cultured in dulbecco's minimum essential medium (DMEM) cell culture medium. The in vitro C6 cell cultures were stereotaxically implanted into the right caudate nucleus of rat brain. Presence of tumor was confirmed with Factor VIII R, hematoxylin–eosin stain, staining of glial fibrillary acid protein, and S-100 immunohistochemistry. After magnetic resonance (MR) scanning and correction of tumor location, the models were divided into groups according to the treating time and laser power (2–10 W). Semiconductor laser optical fibers were inserted in tumors for LITT. Cortex's temperature conducted from the center target was measured using infrared thermograph, and deep-tissue temperature around the target was measured using a thermocouple. Results: Rat C6 gliomas were inoculated with optimized stereotactic technique. These gliomas resembled human glioma in terms of histopathological features. Such models are more reliable and reproducible, with 100% yield of intracranial tumor and no extracranial growth extension. The difference between cortex temperature conducted from center target and deep-tissue temperature around target was not statistically significant. Conclusion: The rat C6 brain glioma model established in the study was a perfect model to study LITT of glioma. Infrared thermograph technique measured temperature conveniently and effectively. The technique is noninvasive, and the obtained data could be further processed using software used in LITT research. To measure deep-tissue temperature, combining thermocouple with infrared thermograph technique would present better results. PMID:25883843

  13. A Novel Murine Model of Established Staphylococcal Bone Infection in the Presence of a Fracture Fixation Plate to Study Therapies Utilizing Antibiotic-laden Spacers after Revision Surgery

    PubMed Central

    Inzana, Jason A.; Schwarz, Edward M.; Kates, Stephen L.; Awad, Hani A.

    2014-01-01

    Mice are the small animal model of choice in biomedical research due to the low cost and availability of genetically engineered lines. However, the devices utilized in current mouse models of implant-associated bone infection have been limited to intramedullary or trans-cortical pins, which are not amenable to treatments involving extensive debridement of a full-thickness bone loss and placement of a segmental antibiotic spacer. To overcome these limitations, we developed a clinically faithful model that utilizes a locking fracture fixation plate to enable debridement of an infected segmental bone defect (full-thickness osteotomy) during a revision surgery, and investigated the therapeutic effects of placing an antibiotic-laden spacer in the segmental bone defect. To first determine the ideal time point for revision following infection, a 0.7 mm osteotomy in the femoral mid-shaft was stabilized with a radiolucent PEEK fixation plate. The defect was inoculated with bioluminescent Staphylococcus aureus, and the infection was monitored over 14 days by bioluminescent imaging (BLI). Osteolysis and reactive bone formation were assessed by X-ray and micro-computed tomography (micro-CT). The active bacterial infection peaked by 5 days post-inoculation, however the stability of the implant fixation became compromised by 10–14 days post-inoculation due to osteolysis around the screws. Thus, day 7 was defined as the ideal time point to perform the revision surgery. During the revision surgery, the infected tissue was debrided and the osteotomy was widened to 3 mm to place a poly-methyl methacrylate spacer, with or without vancomycin. Half of the groups also received systemic vancomycin for the remaining 21 days of the study. The viable bacteria remaining at the end of the study were measured using colony forming unit assays. Volumetric bone changes (osteolysis and reactive bone formation) were directly measured using micro-CT image analysis. Mice that were treated with

  14. An Anterior Cruciate Ligament Reconstruction Technique With 4-Strand Semitendinosus Grafts, Using Outside-In Tibial Tunnel Drilling and Suspensory Fixation Devices

    PubMed Central

    Colombet, Philippe; Graveleau, Nicolas

    2015-01-01

    We describe an anatomic single-bundle anterior cruciate ligament reconstruction using a 4-strand semitendinosus graft fixed with 2 Pullup adjustable suspensory fixation systems (SBM, Lourdes, France). Outside-in full tibial tunnel drilling represents a secure option for length management of the graft. The preferred graft choice is a 4-strand semitendinosus autologous graft. A special technique is used to stitch the graft with a figure-of-8 stitch to load the 4 strands. The Pullup adjustable loop is equipped with 2 buttons of different sizes: a small button for the standard Pullup system on the femoral side and a large button for the Pullup XL system on the tibial side. With this method, graft tension is equally distributed among the 4 strands and the graft cannot bottom out in the tibial tunnel in case of inadequate graft length. PMID:26697313

  15. Mechanical Comparison of Headless Screw Fixation and Locking Plate Fixation for Talar Neck Fractures.

    PubMed

    Karakasli, Ahmet; Hapa, Onur; Erduran, Mehmet; Dincer, Cemal; Cecen, Berivan; Havitcioglu, Hasan

    2015-01-01

    For talar neck fractures, open reduction and internal fixation have been thought to facilitate revascularization and prevent osteonecrosis. Newer screw systems allow for placement of cannulated headless screws, which provide compression by virtue of a variable pitch thread. The present study compared the biomechanical fixation strength of cannulated headless variable-pitch screw fixation and locking plate fixation. A reproducible talar neck fracture was created in 14 fresh cadaver talar necks. Talar head fixation was then performed using 2 cannulated headless variable-pitch 4-mm/5-mm diameter (4/5) screws (Acutrak; Acumed, Hillsboro, OR) and locking plate fixation. Headless variable-pitch screw fixation had lower failure displacement than did locking plate fixation. No statistically significant differences were found in failure stiffness, yield stiffness (p = .655), yield load (p = .142), or ultimate load between the 2 fixation techniques. Cannulated headless variable-pitch screw fixation resulted in better failure displacement than locking plate fixation in a cadaveric talus model and could be considered a viable option for talus fracture fixation. Headless, fully threaded, variable-pitch screw fixation has inherent advantages compared with locking plate fixation, because it might cause less damage to the articular surface and can compress the fracture for improved reduction. Additionally, plate fixation can increase the risk of avascular necrosis owing to the wider incision and dissection of soft tissues.

  16. Nonbridging external fixation of distal radius fractures.

    PubMed

    Eichenbaum, Matthew D; Shin, Eon K

    2010-08-01

    Surgical management of distal radius fractures continues to evolve because of their high incidence in an increasingly active elderly population. Traditional radiocarpal external fixation relies on ligamentotaxis for fracture reduction but has several drawbacks. Nonbridging external fixation has evolved to provide early wrist mobility in the setting of anatomic fracture reduction. Several studies of the nonbridging technique have demonstrated satisfactory results in isolated nonbridging external fixation series and in comparison with traditional spanning external fixation. Nonbridging external fixation for surgical treatment of distal radius fractures can be technically demanding and requires at least 1 cm of intact volar cortex in the distal fracture fragment for successful implementation.

  17. Quantification of the contribution of biological nitrogen fixation to tropical green manure crops and the residual benefit to a subsequent maize crop using 15N-isotope techniques.

    PubMed

    Ramos, M G; Villatoro, M A; Urquiaga, S; Alves, B J; Boddey, R M

    2001-10-01

    In this study the contribution of biological N2 fixation (BNF) to leguminous green manures was quantified in the field at different sites with different 15N methodologies. In the first experiment, conducted on a Terra Roxa soil in Cuba, the BNF contribution to three legumes (Crotalaria juncea, Mucuna aterrima and Canavalia ensiformis) was quantified by applying 15N-labelled ammonium sulphate to the soil. The second experiment was planted in a very low fertility sandy soil near Rio de Janeiro, and the 15N natural abundance technique was applied to quantify BNF in C. juncea, M. niveum and soybean. In both studies the advantages of using several non-N2-fixing reference plants was apparent and despite the much greater accumulation of the C. juncea in the experiment performed on the fertile soil of Cuba, the above ground contributions of BNF at both sites were similar (40-80 kg N x ha(-1)) and greater than for the other legumes. In a further experiment the possible contribution of root-derived N to the soil/plant system of two of the legumes was quantified using a 15N-leaf-labelling technique performed in pots. The results of this study suggested that total below-ground N could constitute as much as 39 to 49% of the total N accumulated by the legume crops. PMID:11566383

  18. A Comparison of Clinical Outcomes of Dislocated Intraocular Lens Fixation between In Situ Refixation and Conventional Exchange Technique Combined with Vitrectomy

    PubMed Central

    Eum, Sun Jung; Kim, Myung Jun; Kim, Hong Kyun

    2016-01-01

    Purpose. To evaluate surgical efficacy of in situ refixation technique for dislocated posterior chamber intraocular lens (PCIOL). Methods. This was a single-center retrospective case series. 34 patients (34 eyes) who underwent sclera fixation for dislocated IOLs combined with vitrectomy were studied. Of 34 eyes, 17 eyes underwent IOL exchange and the other 17 eyes underwent in situ refixation. Results. Mean follow-up period was 6 months. Mean logMAR best corrected visual acuity (BCVA) was not significantly different between the groups 6 months after surgery (0.10 ± 0.03 in the IOL exchange group and 0.10 ± 0.05 in the refixation group; p = 0.065). Surgically induced astigmatism (SIA) was significantly lower in the refixation group (0.79 ± 0.41) than in the IOL exchange group (1.29 ± 0.46) (p = 0.004) at 3 months, which persisted to 6 months (1.13 ± 0.18 in the IOL exchange group and 0.74 ± 0.11 in the refixation group; p = 0.006). Postoperative complications occurred in 3 eyes in the IOL exchange group (17.6%) and 2 eyes in the refixation group (11.8%). However, all of the patients were well managed without additional surgery. Conclusion. The in situ refixation technique should be preferentially considered if surgery is indicated since it seemed to produce a sustained less SIA compared to IOL exchange. PMID:27119019

  19. Ethanol-glycerin fixation with thymol conservation: a potential alternative to formaldehyde and phenol embalming.

    PubMed

    Hammer, Niels; Löffler, Sabine; Feja, Christine; Sandrock, Mara; Schmidt, Wolfgang; Bechmann, Ingo; Steinke, Hanno

    2012-01-01

    Anatomical fixation and conservation are required to prevent specimens from undergoing autolysis and decomposition. While fixation is the primary arrest of the structures responsible for autolysis and decomposition, conservation preserves the state of fixation. Although commonly used, formaldehyde has been classified as carcinogenic to humans. For this reason, an adequate substitute was developed. Ethanol-glycerin fixation and thymol conservation are described and compared with formaldehyde and phenol in this technical report. The setup, tissue qualities, financial aspects, and health concerns of this method are discussed. Ethanol-glycerin fixation and thymol conservation provide outstanding haptic and optic tissue qualities. Typical formaldehyde and phenol effects, such as skin, airway, and eye irritation, as well as carcinogenic effects, can be circumvented by using ethanol-glycerin and thymol instead. Ethanol-glycerin fixation is more expensive than formaldehyde and requires an explosion-proof facility. However, the absence of health effects and its convincing tissue qualities balance these higher costs. Therefore, ethanol-glycerin fixation and thymol conservation provide a potential alternative and complement established fixation techniques. The use of carcinogenic formaldehyde and toxic phenol can be effectively restricted through the use of the described method.

  20. IDENTIFICATION OF CANINE VISCERAL LEISHMANIASIS IN A PREVIOUSLY UNAFFECTED AREA BY CONVENTIONAL DIAGNOSTIC TECHNIQUES AND CELL-BLOCK FIXATION

    PubMed Central

    ABRANTES, Tuanne Rotti; MADEIRA, Maria de Fátima; da SILVA, Denise Amaro; PERIÉ, Carolina dos Santos F. S.; V. MENDES, Artur Augusto; MENEZES, Rodrigo Caldas; SILVA, Valmir Laurentino; FIGUEIREDO, Fabiano Borges

    2016-01-01

    After the report of a second case of canine visceral leishmaniasis (CVL) in São Bento da Lagoa, Itaipuaçu, in the municipality of Maricá, Rio de Janeiro State, an epidemiological survey was carried out, through active search, totaling 145 dogs. Indirect immunofluorescence assay (IFA), enzyme-linked immunosorbent assay (ELISA), and rapid chromatographic immunoassay based on dual-path platform (DPP(r)) were used to perform the serological examinations. The parasitological diagnosis of cutaneous fragments was performed by parasitological culture, histopathology, and immunohistochemistry. In the serological assessment, 21 dogs were seropositive by IFA, 17 by ELISA, and 11 by DPP(r), with sensitivity of 66.7%, 66.7% and 50%, and specificity of 87.2%, 90.2% and 94%, respectively for each technique. The immunohistochemistry of bone marrow using the cell-block technique presented the best results, with six positive dogs found, three of which tested negative by the other parasitological techniques. Leishmania sp. was isolated by parasitological culture in three dogs. The detection of autochthonous Leishmania infantum in Itaipuaçu, and the high prevalence of seropositive dogs confirm the circulation of this parasite in the study area and alert for the risk of expansion in the State of Rio de Janeiro. PMID:26910449

  1. EVALUATION OF PATIENTS UNDERGOING FIXATION OF DIAPHYSEAL HUMERAL FRACTURES USING THE MINIMALLY INVASIVE BRIDGE-PLATE TECHNIQUE

    PubMed Central

    Superti, Mauro José; Martynetz, Fábio; Falavinha, Ricardo Sprenger; Fávaro, Rodrigo Caldonazzo; Boas, Luis Felipe Villas; Filho, Salim Mussi; Martynetz, Juliano; Ribas, Bruno

    2015-01-01

    Objective: The aim was to describe the experience of our group in treating humeral shaft fractures using the bridge–plate technique via an anterior approach. Methods: Seventeen patients with acute diaphyseal humeral fractures with an indication for surgical treatment who were operated in 2006–2010 were evaluated. The AO and Gustilo & Anderson classifications were used. All the patients were operated using the anterior bridge-plate technique and completed a follow–up period of at least twelve months. Results: Sixteen men and one woman were treated. Their mean age was 31.8 years (18–52). Among the injury mechanisms found were: five motorcycle accidents, four car accidents, three fractures due to firearm projectiles, two falls to the ground and finally, with one case each, assault, crushing and being run over. Eight patients had open fractures: two grade I, one grade II, four grade IIIa and one grade IIIb, according to the Gustilo-Anderson classification. In relation to the AO classification, we found: one 12A1, three 12A2, four 12A3, one 12B1, four 12 B2, three 12B3 and one 12C2. The mean postoperative follow-up was 25 months (12–48). As complications, two patients had pain in the elbow and a ROM deficit and one had deep infection. The mean time taken to achieve consolidation was 17.5 weeks. There was no loss of reduction, pseudarthrosis or malunion in this series of patients. Conclusion: The authors believe that the technique described has low rates of complications and morbidity, with good initial results, although the series is limited by the small sample. PMID:27042639

  2. Arthroscopic Meniscal Allograft Transplantation With Soft-Tissue Fixation Through Bone Tunnels

    PubMed Central

    Spalding, Tim; Parkinson, Ben; Smith, Nick A.; Verdonk, Peter

    2015-01-01

    Meniscal allograft transplantation improves clinical outcomes for patients with symptomatic meniscus-deficient knees. We describe an established arthroscopic technique for meniscal allograft transplantation without the need for bone fixation of the meniscal horns. After preparation of the meniscal bed, the meniscus is parachuted into the knee through a silicone cannula and the meniscal horns are fixed with sutures through bone tunnels. The body of the meniscus is then fixed with a combination of all-inside and inside-out sutures. This technique is reliable and reproducible and has clinical outcomes comparable with those of bone plug fixation techniques. PMID:26900554

  3. Stereotactic atlantoaxial transarticular screw fixation.

    PubMed

    Laherty, R W; Kahler, R J; Walker, D G; Tomlinson, F H

    2005-01-01

    Atlantoaxial stabilisation can be performed using a variety of surgical techniques. Developments in spinal instrumentation and stereotactic technology have been incorporated into these procedures. We have recently adopted frameless stereotaxy to assist in such operations. A retrospective study of patients treated by the authors and using frameless stereotaxy from 2001 to 2002 was performed. Each patient underwent pre-operative fine-cut CT in the position of fixation. Using these images, screw trajectory was planned. Stereotaxis and fluoroscopy was utilised during fixation. A post-operative CT was performed. There were nine patients. Bilateral screw placement was achieved in eight. In the remaining case stereotactic planning predicted the single screw fixation. There were no post-operative complications. Post-operative CT showed screw placement corresponding to the planned trajectory in all 17 screws. Stabilisation was achieved in all. Stereotactic atlantoaxial screw fixation is an accessible, safe and accurate method for the management of C1-2 instability. PMID:15639416

  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. Fixation of chiral smectic liquid crystal (S)-(+)-4-(2-methyl-1-butyloyloxy)phenyl 4-[1-(propenoyloxy) butiloxy] benzoate using UV curing techniques

    SciTech Connect

    Afrizal, Nurdelima,; Umeir; Hikam, Muhammad; Soegiyono, Bambang; Riswoko, Asep

    2014-03-24

    Chiral Smectic Liquid Crystal (S)-(+)-4-(2-methyl-1-butyloyloxy)phenyl 4-[1-(propenoyloxy) butiloxy] benzoate has been synthesized using method of steglich esterification at room temperature. The mesomorphic behavior of chiral smectic at 55°C that showed schlieren texture in POM analysis. Fixation of structure chiral smectic liquid crystal by means of photopolymerization of monomer (S)-(+)-4-(2-methyl-1-butyloyloxy)phenyl 4-[1-(propenoyloxy) butiloxy] benzoate under UV irradiation which called UV curing techniques. The curing process using UV 3 lamps 100 volt at 60°C for an hour. The product of photopolymerization could be seen by analysis of FTIR spectra both monomer and polymer. FTIR spectra of monomer, two peaks for ester carbonyl and C-C double bond groups appeared at 1729.09 cm-1and 3123.46 cm{sup −1}. After UV curing process, peak for the carbonyl group at 1729.09 cm{sup −1} decreased and a new peak at 1160.21 cm{sup −1} appeared due to the carbonyl group attached to a C-C bond group and then peak at 3123.46 cm{sup −1} for C-C double bond group was disappeared.

  6. Fixation of chiral smectic liquid crystal (S)-(+)-4-(2-methyl-1-butyloyloxy)phenyl 4-[1-(propenoyloxy) butiloxy] benzoate using UV curing techniques

    NASA Astrophysics Data System (ADS)

    Afrizal, Hikam, Muhammad; Soegiyono, Bambang; Riswoko, Asep; Nurdelima, Umeir

    2014-03-01

    Chiral Smectic Liquid Crystal (S)-(+)-4-(2-methyl-1-butyloyloxy)phenyl 4-[1-(propenoyloxy) butiloxy] benzoate has been synthesized using method of steglich esterification at room temperature. The mesomorphic behavior of chiral smectic at 55°C that showed schlieren texture in POM analysis. Fixation of structure chiral smectic liquid crystal by means of photopolymerization of monomer (S)-(+)-4-(2-methyl-1-butyloyloxy)phenyl 4-[1-(propenoyloxy) butiloxy] benzoate under UV irradiation which called UV curing techniques. The curing process using UV 3 lamps 100 volt at 60°C for an hour. The product of photopolymerization could be seen by analysis of FTIR spectra both monomer and polymer. FTIR spectra of monomer, two peaks for ester carbonyl and C-C double bond groups appeared at 1729.09 cm-1and 3123.46 cm-1. After UV curing process, peak for the carbonyl group at 1729.09 cm-1 decreased and a new peak at 1160.21 cm-1 appeared due to the carbonyl group attached to a C-C bond group and then peak at 3123.46 cm-1 for C-C double bond group was disappeared.

  7. Free Hand Insertion Technique of S2 Sacral Alar-Iliac Screws for Spino-Pelvic Fixation: Technical Note, Acadaveric Study.

    PubMed

    Park, Jong-Hwa; Hyun, Seung-Jae; Kim, Ki-Jeong; Jahng, Tae-Ahn

    2015-12-01

    A rigid spino-pelvic fixation to anchor long constructs is crucial to maintain the stability of long fusion in spinal deformity surgery. Besides obtaining immediate stability and proper biomechanical strength of constructs, the S2 alar-iliac (S2AI) screws have some more advantages. Four Korean fresh-frozen human cadavers were procured. Free hand S2AI screw placement is performed using anatomic landmarks. The starting point of the S2AI screw is located at the midpoint between the S1 and S2 foramen and 2 mm medial to the lateral sacral crest. Gearshift was advanced from the desired starting point toward the sacro-iliac joint directing approximately 20° angulation caudally in sagittal plane and 30° angulation horizontally in the coronal plane connecting the posterior superior iliac spine (PSIS). We made a S2AI screw trajectory through the cancellous channel using the gearshift. We measured caudal angle in the sagittal plane and horizontal angle in the coronal plane. A total of eight S2AI screws were inserted in four cadavers. All screws inserted into the iliac crest were evaluated by C-arm and naked eye examination by two spine surgeons. Among 8 S2AI screws, all screws were accurately placed (100%). The average caudal angle in the sagittal plane was 17.3±5.4°. The average horizontal angle in the coronal plane connecting the PSIS was 32.0±1.8°. The placement of S2AI screws using the free hand technique without any radiographic guidance appears to an acceptable method of insertion without more radiation or time consuming. PMID:26819698

  8. 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

  9. Novel application of an established technique for removing a knotted ureteric stent.

    PubMed

    Tempest, Heidi; Turney, Ben; Kumar, Sunil

    2011-01-01

    This report describes a case whereby a ureteric stent became knotted during removal and lodged within the upper ureter. The authors describe a novel minimally invasive technique to remove the knotted ureteric stent using the holmium laser. PMID:22701009

  10. Established and Emerging Atmospheric Pressure Surface Sampling/Ionization Techniques for Mass Spectrometry

    SciTech Connect

    Van Berkel, Gary J; Pasilis, Sofie P; Ovchinnikova, Olga S

    2008-01-01

    The number and type of atmospheric pressure techniques suitable for sampling analytes from surfaces, forming ions from those analytes, and subsequently transporting those ions into vacuum for interrogation by mass spectrometry has rapidly expanded over the last several years. Moreover, the literature in this area is complicated by an explosion in acronyms for these techniques, many of which provide no information relating to the chemical or physical processes involved. In this review, we sort this vast array of techniques into a relatively few categories on the basis of the approaches used for surface sampling and ionization. For each technique, we explain, as best known, many of the underlying principles of operation, describe representative applications, and in some cases, discuss needed research or advancements and attempt to forecast their future analytical utility.

  11. Intraocular lens fixation with dacron.

    PubMed

    Peyman, G A; Koziol, J E

    1978-10-01

    To overcome the problem of postoperative lens dislocation, we evaluated a new means of lens fixation. Our experimental studies in rabbits and primates demonstrated that Dacron polyethylene terephtalate induced a cellular reaction from either the anterior or posterior iris surface when placed in contact with the iris, thereby establishing a bond between the Dacron fibers and the iris. Dacron mesh can be attached to the distal portion of either the anterior or posterior loops of a Binkhorst iris clip (4-loop) lens. In the rabbit eye, lens fixation occurred within five days; in the primate eye, 30 days. When combined with silk, Dacron produced tissue ingrowth in the primate eye within 14 days. No unwanted reaction occurred in any animal with the Dacron and silk combination. Being biodegradable, the silk induced faster cellular ingrowth than the Dacron. However, Dacron, which is not biodegradable, provided a permanent means of fixation. PMID:155053

  12. 15 CFR 923.42 - State establishment of criteria and standards for local implementation-Technique A.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT COASTAL ZONE MANAGEMENT PROGRAM REGULATIONS... zone. The first such control technique, at subsection 306(d)(11)(A) of the Act, is state establishment... zone subject to the management program and the power to prohibit, modify or condition those...

  13. 15 CFR 923.42 - State establishment of criteria and standards for local implementation-Technique A.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT COASTAL ZONE MANAGEMENT PROGRAM REGULATIONS... zone. The first such control technique, at subsection 306(d)(11)(A) of the Act, is state establishment... zone subject to the management program and the power to prohibit, modify or condition those...

  14. 15 CFR 923.42 - State establishment of criteria and standards for local implementation-Technique A.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT COASTAL ZONE MANAGEMENT PROGRAM REGULATIONS... zone. The first such control technique, at subsection 306(d)(11)(A) of the Act, is state establishment... zone subject to the management program and the power to prohibit, modify or condition those...

  15. 15 CFR 923.42 - State establishment of criteria and standards for local implementation-Technique A.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT COASTAL ZONE MANAGEMENT PROGRAM REGULATIONS... zone. The first such control technique, at subsection 306(d)(11)(A) of the Act, is state establishment... zone subject to the management program and the power to prohibit, modify or condition those...

  16. 15 CFR 923.42 - State establishment of criteria and standards for local implementation-Technique A.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT COASTAL ZONE MANAGEMENT PROGRAM REGULATIONS... zone. The first such control technique, at subsection 306(d)(11)(A) of the Act, is state establishment... zone subject to the management program and the power to prohibit, modify or condition those...

  17. Techniques of Play Activity at Physical Education Classes at Specialized Secondary Educational Establishments

    ERIC Educational Resources Information Center

    Martynova, Victoria A.; Kapustin, Aleksandr G.

    2016-01-01

    The issue is urgent today because at present the organization and content of Physical Education (PE) classes at specialized secondary educational establishments (SSEEs) do not completely meet contemporary requirements. The following negative trends prove that, namely: the physical and psychological health decline in school leavers and students,…

  18. Suspensory Anterior Tibial Fixation in the Anatomic Transtibial Posterior Cruciate Ligament Reconstruction

    PubMed Central

    Elazab, Ashraf; Lee, Yong Seuk; Kang, Seo Goo

    2016-01-01

    The transtibial technique is the most relevant among many surgical techniques for posterior cruciate ligament reconstruction, and many types of fixation devices are used for tibial fixation according to the technique and the length of the graft. However, bone density in the fixation areas should be taken into consideration when choosing the fixation device to achieve rigid and stable fixation. However, density is not a substantial issue for anteromedial cortical fixation using a cortical suspension device. We describe tibial fixation with a TightRope RT (Arthrex, Naples, FL), which is a cortical suspension device, in anatomic transtibial posterior cruciate ligament reconstruction. PMID:27073781

  19. The Role of Neuroimaging Techniques in Establishing Diagnosis, Prognosis and Therapy in Disorders of Consciousness

    PubMed Central

    Gosseries, Olivia; Pistoia, Francesca; Charland-Verville, Vanessa; Carolei, Antonio; Sacco, Simona; Laureys, Steven

    2016-01-01

    Non-communicative brain damaged patients raise important clinical and scientific issues. Here, we review three major pathological disorders of consciousness: coma, the unresponsive wakefulness syndrome and the minimally conscious state. A number of clinical studies highlight the difficulty in making a correct diagnosis in patients with disorders of consciousness based only on behavioral examinations. The increasing use of neuroimaging techniques allows improving clinical characterization of these patients. Recent neuroimaging studies using positron emission tomography, functional magnetic resonance imaging, electroencephalography and transcranial magnetic stimulation can help assess diagnosis, prognosis, and therapeutic treatment. These techniques, using resting state, passive and active paradigms, also highlight possible dissociations between consciousness and responsiveness, and are facilitating a more accurate understanding of brain function in this challenging population. PMID:27347265

  20. 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.

  1. Issues and implications of establishing guidelines for the use of behavioral techniques.

    PubMed Central

    Sajwaj, T

    1977-01-01

    Several guidelines surrounding the use of behavioral procedures have recently appeared, the best of which is that of the National Association of Retarded Citizens (NARC). Some issues and implications of the establishment of guidelines are briefly reviewed in the context of the NARC guidelines. Issues include the factual versus opinion bases for guidelines and the need to continue the development of explicit behavioral criteria for assessing staff competence. Implications for programs include the impact of guidelines on the professional boundaries, administrative decision-making, and budgeting, together with the dangers of expanding the regulatory bureaucracy. Several miscellaneous impacts are noted, including a potential for curbing innovative behavioral technology. PMID:924921

  2. 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

  3. Establishing the skill of climate field reconstruction techniques for precipitation with pseudoproxy experiments

    NASA Astrophysics Data System (ADS)

    Gómez-Navarro, Juan José; Werner, Johannes; Wagner, Sebastian; Luterbacher, Jürg; Zorita, Eduardo

    2015-09-01

    This study aims at assessing the skill of several climate field reconstruction techniques (CFR) to reconstruct past precipitation over continental Europe and the Mediterranean at seasonal time scales over the last two millennia from proxy records. A number of pseudoproxy experiments are performed within the virtual reality of a regional paleoclimate simulation at 45 km resolution to analyse different aspects of reconstruction skill. Canonical Correlation Analysis (CCA), two versions of an Analog Method (AM) and Bayesian hierarchical modeling (BHM) are applied to reconstruct precipitation from a synthetic network of pseudoproxies that are contaminated with various types of noise. The skill of the derived reconstructions is assessed through comparison with precipitation simulated by the regional climate model. Unlike BHM, CCA systematically underestimates the variance. The AM can be adjusted to overcome this shortcoming, presenting an intermediate behaviour between the two aforementioned techniques. However, a trade-off between reconstruction-target correlations and reconstructed variance is the drawback of all CFR techniques. CCA (BHM) presents the largest (lowest) skill in preserving the temporal evolution, whereas the AM can be tuned to reproduce better correlation at the expense of losing variance. While BHM has been shown to perform well for temperatures, it relies heavily on prescribed spatial correlation lengths. While this assumption is valid for temperature, it is hardly warranted for precipitation. In general, none of the methods outperforms the other. All experiments agree that a dense and regularly distributed proxy network is required to reconstruct precipitation accurately, reflecting its high spatial and temporal variability. This is especially true in summer, when a specifically short de-correlation distance from the proxy location is caused by localised summertime convective precipitation events.

  4. Establishment of the genomic in situ hybridization (GISH) technique for analysis in interspecific hybrids of Passiflora.

    PubMed

    Melo, C A F; Silva, G S; Souza, M M

    2015-01-01

    The genomic in situ hybridization (GISH) technique was applied to Passiflora interspecific F1 HD13-133 hybrids (Passiflora sublanceolata x Passiflora foetida) and HD15-101 (Passiflora gardineri x Passiflora gibertii), and the backcrossed hybrids (BC1) HD18-106 and HD18-113 (Passiflora sublanceolata x HD13-133). GISH was performed using genomic probes prepared with the DNA from the paternal genitor, whereas the maternal DNA was used as blocking DNA and employed at various concentrations (20X, 40X, 60X, and 100X) in relation to the probe concentration. At the same time, GISH was applied with the use of simultaneous probes from both genomes, paternal and maternal, that were detected with avidin-FITC and anti-digoxigenin-rhodamine, respectively. Both methodologies allowed the distinguishing of the maternal and paternal genomes, thus confirming the hybrid nature of all the analyzed genotypes. Furthermore, the presence of recombinant chromosomes in BC1 hybrids revealed the occurrence of meiotic recombination in HD13 hybrids. This application of the GISH technique is an important step towards genomic analyses of Passiflora hybrids: it can broaden the phylogenetic and evolutionary studies of the genus and, at the same time, contribute to breeding programs. PMID:25867365

  5. Scaling Analysis Techniques to Establish Experimental Infrastructure for Component, Subsystem, and Integrated System Testing

    SciTech Connect

    Sabharwall, Piyush; O'Brien, James E.; McKellar, Michael G.; Housley, Gregory K.; Bragg-Sitton, Shannon M.

    2015-03-01

    Hybrid energy system research has the potential to expand the application for nuclear reactor technology beyond electricity. The purpose of this research is to reduce both technical and economic risks associated with energy systems of the future. Nuclear hybrid energy systems (NHES) mitigate the variability of renewable energy sources, provide opportunities to produce revenue from different product streams, and avoid capital inefficiencies by matching electrical output to demand by using excess generation capacity for other purposes when it is available. An essential step in the commercialization and deployment of this advanced technology is scaled testing to demonstrate integrated dynamic performance of advanced systems and components when risks cannot be mitigated adequately by analysis or simulation. Further testing in a prototypical environment is needed for validation and higher confidence. This research supports the development of advanced nuclear reactor technology and NHES, and their adaptation to commercial industrial applications that will potentially advance U.S. energy security, economy, and reliability and further reduce carbon emissions. Experimental infrastructure development for testing and feasibility studies of coupled systems can similarly support other projects having similar developmental needs and can generate data required for validation of models in thermal energy storage and transport, energy, and conversion process development. Experiments performed in the Systems Integration Laboratory will acquire performance data, identify scalability issues, and quantify technology gaps and needs for various hybrid or other energy systems. This report discusses detailed scaling (component and integrated system) and heat transfer figures of merit that will establish the experimental infrastructure for component, subsystem, and integrated system testing to advance the technology readiness of components and systems to the level required for commercial

  6. Experience of Delphi technique in the process of establishing consensus on core competencies

    PubMed Central

    Raghav, Pankaja Ravi; Kumar, Dewesh; Bhardwaj, Pankaj

    2016-01-01

    Introduction: The Department of Community Medicine and Family Medicine (CMFM) has been started as a new model for imparting the components of family medicine and delivering health-care services at primary and secondary levels in all six newly established All India Institute of Medical Sciences (AIIMS), but there is no competency-based curriculum for it. The paper aims to share the experience of Delphi method in the process of developing consensus on core competencies of the new model of CMFM in AIIMS for undergraduate medical students in India. Methods: The study adopted different approaches and methods, but Delphi was the most critical method used in this research. In Delphi, the experts were contacted by e-mail and their feedback on the same was analyzed. Results: Two rounds of Delphi were conducted in which 150 participants were contacted in Delphi-I but only 46 responded. In Delphi-II, 26 participants responded whose responses were finally considered for analysis. Three of the core competencies namely clinician, primary-care physician, and professionalism were agreed by all the participants, and the least agreement was observed in the competencies of epidemiologist and medical teacher. The experts having more experience were less consistent as responses were changed from agree to disagree in more than 15% of participants and 6% changed from disagree to agree. Conclusion: Within the given constraints, the final list of competencies and skills for the discipline of CMFM compiled after the Delphi process will provide a useful insight into the development of competency-based curriculum of the subject. PMID:27563586

  7. Medial Closing-Wedge Distal Femoral Osteotomy: Fixation With Proximal Tibial Locking Plate

    PubMed Central

    Tírico, Luís Eduardo Passarelli; Demange, Marco Kawamura; Bonadio, Marcelo Batista; Helito, Camilo Partezani; Gobbi, Riccardo Gomes; Pécora, José Ricardo

    2015-01-01

    Distal femoral varus osteotomy is a well-established procedure for the treatment of lateral compartment cartilage lesions and degenerative disease, correcting limb alignment and decreasing the progression of the pathology. Surgical techniques can be performed with a lateral opening-wedge or medial closing-wedge correction of the deformity. Fixation methods for lateral opening-wedge osteotomies are widely available, and there are various types of implants that can be used for fixation. However, there are currently only a few options of implants for fixation of a medial closing-wedge osteotomy on the market. This report describes a medial, supracondylar, V-shaped, closing-wedge distal femoral osteotomy using a locked anterolateral proximal tibial locking plate that fits anatomically to the medial side of the distal femur. This is a great option as a stable implant for a medial closing-wedge distal femoral osteotomy. PMID:26870647

  8. Eye fixation-related potentials (EFRPs) during object identification.

    PubMed

    Rämä, Pia; Baccino, Thierry

    2010-11-01

    Eye fixation-related potential (EFRP) measures electrical brain activity in response to eye fixations. The aim of the current study was to investigate whether the EFRPs vary during consecutive eye fixations while subjects were performing an object identification task. Eye fixations evoked P1 and N1 components at the occipital and parietal recording sites. The latency of P1 component increased during consecutive fixations. The amplitude of P1 increased and the amplitude of N1 decreased during consecutive fixations. The results indicate that EFRPs are modulated during consecutive fixations, suggesting that the current technique may provide a useful tool to study temporal dynamics of visual perception and processes underlying object identification.

  9. Single-Specimen Technique to Establish the J-Resistance of Linear Viscoelastic Solids with Constant Poisson's Ratio

    NASA Technical Reports Server (NTRS)

    Gutierrez-Lemini, Danton; McCool, Alex (Technical Monitor)

    2001-01-01

    A method is developed to establish the J-resistance function for an isotropic linear viscoelastic solid of constant Poisson's ratio using the single-specimen technique with constant-rate test data. The method is based on the fact that, for a test specimen of fixed crack size under constant rate, the initiation J-integral may be established from the crack size itself, the actual external load and load-point displacement at growth initiation, and the relaxation modulus of the viscoelastic solid, without knowledge of the complete test record. Since crack size alone, of the required data, would be unknown at each point of the load-vs-load-point displacement curve of a single-specimen test, an expression is derived to estimate it. With it, the physical J-integral at each point of the test record may be established. Because of its basis on single-specimen testing, not only does the method not require the use of multiple specimens with differing initial crack sizes, but avoids the need for tracking crack growth as well.

  10. Biomechanical evaluation of maxillary Lefort Ι fracture with bioabsorbable osteosynthesis internal fixation.

    PubMed

    Wu, Wei; Zhou, Jiang; Xu, Chong-Tao; Zhang, Jie; Jin, Yan-Jiao; Sun, Geng-Lin

    2014-12-01

    The aim of this study was to apply biomechanical analysis model to evaluate the effects of bioabsorbable internal fixation devices on maxillary Lefort Ι fracture. CT scan technology and the finite element software (ansys) were used to establish three-dimensional finite element models of five resorbable internal fixation devices in maxillary Lefort Ι fractures. We used the model to calculate the stress of the upper jaw and internal fixation. We further analyzed the stability of fixation under four occlusions. The fixation using two bioabsorbable plates was not stable. The zygomaticomaxillary pillars fixation is more stable than other fixations. The stability of fracture fixation was influenced with the molar occlusion. The current study developed a functional three-dimensional finite element model of bioabsorbable internal fixation and compared the stability of five fixation methods for maxillary Lefort Ι fractures. The results would facilitate the application of bioabsorbable materials in dental clinic.

  11. Protein detection in gels without fixation.

    PubMed

    Joo, Won-A; Speicher, David W

    2007-05-01

    A number of alternative methods are described for detecting proteins in polyacrylamide gels that do not require fixation of the protein either prior to staining or in conjunction with staining. The primary advantage of avoiding fixation is that this makes it easier to remove proteins of interest from the gels for subsequent analysis. In general, the sensitivity of protein detection methods that avoid fixation is lower than for detection methods using fixation. For any given method, sensitivity is dependent on the volume of the protein band within the gel; hence, sensitivity is highest for sharp, narrow bands. Techniques described in this unit include protocols for protein detection in gels by SDS precipitation, preparation of contact blots, staining with imidazole-zinc, and use of the fluorescent labels IAEDANS and fluorescamine. Several additional methods, including the use of tryptophan fluorescence, guide strips, and minimal protein staining, are discussed in the Commentary.

  12. 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

  13. Application of plant growth regulators, a simple technique for improving the establishment success of plant cuttings in coastal dune restoration

    NASA Astrophysics Data System (ADS)

    Balestri, Elena; Vallerini, Flavia; Castelli, Alberto; Lardicci, Claudio

    2012-03-01

    Exogenous application of plant growth regulators (PGRs) may be an effective technique for increasing the rooting ability and the growth of vegetative fragments (cuttings) of plants used in dune restoration programs. Various concentrations (0, 50 and 100 mg l-1) of two auxins, alpha-naphtaleneacetic acid (NAA) and indole-3-butyric acid (IBA), and two cytokinins, 6-furfurylaminopurine (Kinetin) and 6-benzylaminopurine (BAP), were applied separately to cuttings of two widely used species for restoration, Ammophila arenaria and Sporobuls virginicus. Root development and production of new buds in cuttings were examined under laboratory conditions one month after application. Cuttings were also examined one year after transplanting into a sandy substratum under natural conditions, to test for possible long term effects of PGRs on plant establishment success and growth. The response of the two study species to PGRs differed substantially. In A. arenaria the auxin NAA at 100 mg l-1 reduced the time for root initiation and increased the rooting capacity of cuttings, while the cytokinin Kinetin at 50 mg l-1 facilitated root growth. No auxin had effect on rooting or growth of S. virginicus cuttings, but treatment with 100 mg l-1 Kinetin resulted in higher rooting success than the control. One year after planting, the cuttings of A. arenaria treated with 100 mg l-1 NAA showed a higher establishment success (90% vs. 55%) and produced more culms and longer roots than the control; those treated with cytokinins did not differ in the establishment success from the control, but had longer roots, more culms and rhizomes. On the other hand, the cuttings of S. virginicus treated with 100 mg l-1 Kinetin showed a higher establishment success (75% vs. 35%) and had more culms than the control. Therefore, in restoration activities that involved A. arenaria, a pre-treatment of cuttings with NAA would be beneficial, as it allows the production of a higher number of well-developed plants with

  14. Establishment of an operating room committee and a training program to improve aseptic techniques for rodent and large animal surgery.

    PubMed

    Héon, Hélène; Rousseau, Nathalie; Montgomery, Jane; Beauregard, Gilles; Choiniére, Manon

    2006-11-01

    Investigators of our research facility generally accept the concept of asepsis as an important component of adequate surgical care for animals. However, they experience difficulties putting it into practice, especially in the case of rodents. The reasons for this are inconvenience, cost, and lack of training. To better assist investigators in the implementation of aseptic surgical techniques in their laboratories, we have created an Operating Room (OR) Committee modeled after OR committees found in human hospitals. A reconstructive surgeon, a veterinarian, a research scientist, a nurse involved in the training of OR personnel, interns, graduate students, and an animal health technician were chosen as committee members in light of their OR and animal care expertise. The first task of the OR Committee was to establish institutional guidelines for aseptic surgery, taking into account the costs imposed on research budgets by these procedures. The OR Committee also supports a complete training program in aseptic surgery techniques, which consists of lectures, a training manual, videos, and a practical course. Furthermore, when experimental procedures require specialized equipment, the OR Committee collaborates with researchers to develop strategies to achieve asepsis. This OR Committee and the training program proved to be important tools to promote and improve the quality of animal care during surgery.

  15. Proposal for an analytical sequence aimed at establishing sutcco's composition and technique used: research on samples collected in southern Switzerland

    NASA Astrophysics Data System (ADS)

    Cavallo, Giovanni; Moresi, Marco

    2005-06-01

    The paper presents the results of experiments obtained using different analytical techniques (optical and electronic microscopy, infrared spectroscopy, powder X-ray diffraction, X-ray fluorescence, microanalysis) performed on stucco's samples collected in churches and historical buildings in Canton Ticino and Canton Grigioni (Southern Switzerland). The research is principally oriented towards establishing the better analytical sequence for an efficacious characterization of materials and techniques used in making stuccos, in order to satisfy restoration requests. Plastic decorations (stuccoes of 17th and 18th century), imitation marble vertical surfaces - stucco lustro - (19th century) and decorative elements as stucco lustro (17th century) were studied. The experimental data showed the same bottom layer for all the samples; different categories of stucco are distinguishable observing finishing layer characteristics. Petrographic examinations and spectroscopic infrared analyses represent a suitable survey sequence, working on samples of millimetric size (low invasive and high representative criteria for sampling), considering that it is an usual necessity to divide mechanically the different parts of the same material, as for example bottom layer and finishing one, to detect the presence of organic compounds in each layer. More significant results should be obtained employing electron microscope and microanalysis, using the same thin polished section of optical examinations. Mineralogical and chemical analyses performed by X-ray diffraction and X-ray fluorescence require a greater sample availability but in this way it is possible to obtain more complete and representative information specifying compounds bound to alteration processes and/or to previous restoration interventions.

  16. Establishment of optimal scan delay for multi-phase computed tomography using bolus-tracking technique in canine pancreas.

    PubMed

    Choi, Soo-Young; Choi, Ho-Jung; Lee, Ki-Ja; Lee, Young-Won

    2015-09-01

    To establish a protocol for a multi-phase computed tomography (CT) of the canine pancreas using the bolus-tracking technique, dynamic scan and multi-phase CT were performed in six normal beagle dogs. The dynamic scan was performed for 60 sec at 1-sec intervals after the injection (4 ml/sec) of a contrast medium, and intervals from aortic enhancement appearance to aortic, pancreatic parenchymal and portal vein peaks were measured. The multi-phase CT with 3 phases was performed three times using a bolus-tracking technique. Scan delays were 0, 15 and 30 in first multi-phase scan; 5, 20 and 35 in second multi-phase scan; and 10, 25 and 40 sec in third multi-phase scan, respectively. Attenuation values and contrast enhancement pattern were analyzed from the aorta, pancreas and portal vein. The intervals from aortic enhancement appearance to aortic, pancreatic parenchymal and portal vein peaks were 3.8 ± 0.7, 8.7 ± 0.9 and 13.3 ± 1.5 sec, respectively. The maximum attenuation values of the aorta, pancreatic parenchyma and portal vein were present at scan sections with no scan delay, a 5-sec delay and a 10-sec delay, respectively. When a multi-phase CT of the canine pancreas is triggered at aortic enhancement appearance using a bolus-tracking technique, the recommended optimal delay times of the arterial and pancreatic parenchymal phases are no scan delay and 5 sec, respectively. PMID:25843155

  17. 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

  18. 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

  19. 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…

  20. 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.

  1. Acetabular liner fixation by cement.

    PubMed

    Jiranek, William A

    2003-12-01

    Many situations in revision THA require the exchange of a PE liner in the setting of a well-fixed cementless acetabular shell. Unfortunately, a replacement liner is not always available, the locking mechanism of the metal shell may be damaged or incompatible with the desired liner, or the shell is malpositioned. Revision of a well-fixed cementless acetabular shell has been associated with considerable morbidity. This raises several questions: can a new PE liner be fixed in the existing shell using bone cement, and if so, which techniques can improve the end result, and in which patients should they be used? Biomechanical testing of cemented PE liners has shown initial fixation strengths that exceed conventional locking mechanisms. It is not known during what period this initial fixation will fail, but clinical reports with followup of as many as 6 years have shown survival in approximately 90% of cases. These studies have shown the importance of proper patient selection, accurate sizing of the PE liner, careful preparation of the substrate of the liner and the shell, and good cement technique. The potential advantages of this technique are less surgical morbidity, more rapid surgery and patient recovery, the ability to incorporate antibiotics in the cement, and more liner options.

  2. 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

  3. [Vaginal vault fixation and reinforcement of the rectovaginal septum technique for the treatment of vault prolapse associated or not with rectocele].

    PubMed

    Pigne, Alain; Faux, A; Deval, B

    2011-04-01

    The most important current concept in therapeutic management of female genital prolapse is the use of non absorbable prosthesis through a vaginal approach. The application of these surgical techniques to repair prolapse aims to restore the anatomic position of the pelvis, while preserving urinary, bowel and sexual functions. Since 2005, we use the Apogee® prosthesis for the treatment of both the vault prolapse and associated posterior colpocele. The purpose of this paper is the detailed description of the technique of placement of Apogee® prosthetic system, so that it can be useful to clarify the key points of this surgical reconstructive surgical technique and different gestures associated with the placement of this type of prosthesis.

  4. Comparison of enzyme-linked immunosorbent assay (ELISA) technique and complement-fixation test for estimation of cytomegalovirus IgG antibody.

    PubMed

    Booth, J C; Hannington, G; Aziz, T A; Stern, H

    1979-02-01

    The ELISA technique has been found to be reliable for the detection and titration of cytomegalovirus-specific IgG antibody in serum. It is about six times more sensitive than the CF test although some discrepancies were found between the antibody titres determined by the two methods.

  5. PRE-OPERATIVE PLANNING AND SURGICAL TECHNIQUE OF THE OPEN WEDGE SUPRACONDYLAR OSTEOTOMY FOR CORRECTION OF VALGUS KNEE AND FIXATION WITH A FIXED-ANGLE IMPLANT

    PubMed Central

    Paccola, Cleber Antonio Jansen

    2015-01-01

    The step-by-step preoperative planning for supracondylar opening wedge osteotomy of the femur for precise correction of the load axis of the lower limb using a fixed-angle implant (95° AO blade plate) is presented. The surgical technique and the use of a bone graft from the same site for filling in the defect are also presented. PMID:27026976

  6. 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.

  7. 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

  8. Fixation produced by conflict.

    PubMed

    Karsh, E B

    1970-05-15

    All rats given a choice between a rewarded alternative and a conflict alternative (rewarded and punished) developed position fixations when the position of the alternatives was reversed. In contrast, all animals given one rewarded alternative and another nonrewarded (or punished and nonrewarded) alternative learned to choose the rewarded side during 25 successive reversals.

  9. 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)

  10. 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,…

  11. Fixation produced by conflict.

    PubMed

    Karsh, E B

    1970-05-15

    All rats given a choice between a rewarded alternative and a conflict alternative (rewarded and punished) developed position fixations when the position of the alternatives was reversed. In contrast, all animals given one rewarded alternative and another nonrewarded (or punished and nonrewarded) alternative learned to choose the rewarded side during 25 successive reversals. PMID:5444066

  12. Proximal Periprosthetic Femur Fractures: Strategies for Internal Fixation.

    PubMed

    Moloney, Gele B; Toro, Jose B; Helfet, David L; Wellman, David S

    2016-01-01

    As the number of patients living with total hip arthroplasty continues to rise, there will be an increase in periprosthetic fractures requiring surgical treatment. Treatment of periprosthetic femur fractures below a well-fixed hip arthroplasty stem presents a unique set of challenges. A review of the existing literature on surgical technique, including plate selection and configuration, proximal fixation options, and use of allograft, can serve to guide treatment of these challenging injuries. While not conclusive, the literature supports using soft tissue preserving techniques, bicortical proximal fixation, and fixation spanning the length of the femur. PMID:27327912

  13. Arthroscopic fixation of an avulsion fracture of the tibia involving the posterior cruciate ligament: a modified technique in a series of 22 cases.

    PubMed

    Chen, L B; Wang, H; Tie, K; Mohammed, A; Qi, Y J

    2015-09-01

    A total of 22 patients with a tibial avulsion fracture involving the insertion of the posterior cruciate ligament (PCL) with grade II or III posterior laxity were reduced and fixed arthroscopically using routine anterior and double posteromedial portals. A double-strand Ethibond suture was inserted into the joint and wrapped around the PCL from anterior to posterior to secure the ligament above the avulsed bony fragment. Two tibial bone tunnels were created using the PCL reconstruction guide, aiming at the medial and lateral borders of the tibial bed. The ends of the suture were pulled out through the bone tunnels and tied over the tibial cortex between the openings of the tunnels to reduce and secure the bony fragment. Satisfactory reduction of the fracture was checked arthroscopically and radiographically. The patients were followed-up for a mean of 24.5 months (19 to 28). Bone union occurred six weeks post-operatively. At final follow-up, all patients had a negative posterior drawer test and a full range of movement. KT-1000 arthrometer examination showed that the mean post-operative side-to-side difference improved from 10.9 mm (standard deviation (sd) 0.7) pre-operatively to 1.5 mm (sd 0.6) (p = 0.001). The mean Tegner and the International Knee Documentation Committee scores improved significantly (p = 0.001). The mean Lysholm score at final follow-up was 92.0 (85 to 96). We conclude that this technique is convenient, reliable and minimally invasive and successfully restores the stability and function of the knee.

  14. State of awakeness during visual fixation in preterm infants.

    PubMed

    Hack, M; Muszynski, S Y; Miranda, S B

    1981-07-01

    To demonstrate the presence of discriminable awake states in preterm infants, facial behaviors and visual fixation to a single patterned stimulus were recorded. Five healthy preterm infants born at a mean of 29 weeks' gestation were followed from 30 to 35 weeks' postmenstrual age. Behaviors (eye openness, movements, mouthing, and vocalizations) were recorded simultaneously with visual fixation measured by the corneal reflection technique. Test time was determined by the duration of time the infant remained awake before crying or closing eyes. The presence of both quiet awakeness and drowsiness was demonstrated. Younger infants spent more time in drowsiness, whereas older infants had more quiet awakeness. Visual pattern fixation was observed as early as 30 weeks. Fixation time increased with increasing postmenstrual age. More fixation was observed during quiet awakeness than during drowsiness.

  15. Vergence errors: some hitherto unreported aspects of fixation disparity.

    PubMed

    Reading, R W

    1992-07-01

    Measurement of the monocular components of fixation disparity indicated a higher prevalence of asymmetric contributions to the total deviation than previously reported. Furthermore, the exact proportion varied from moment to moment. Two of six subjects showed significant changes in fixation disparity over a period of 1 week. For all six subjects the changes in fixation deviation of one eye were virtually independent of those changes occurring in the other eye. In other words, these monocular variances were uncorrelated. Settings of the monocular components of binocular fixation disparity were accomplished at an accuracy close to that achieved by using a monocular vernier technique. The remaining differences appeared to be due to occasional instabilities during binocular viewing. The usual method of clinical measurement in which only one element is moved is not always equivalent to that determined by summing the two monocular components. The principal process measured by subjective fixation disparity appears to be either oculomotor or localized directional shifts of a monocular nature.

  16. A Novel Fixation System for Acetabular Quadrilateral Plate Fracture: A Comparative Biomechanical Study

    PubMed Central

    Zha, Guo-Chun; Sun, Jun-Ying; Dong, Sheng-Jie; Zhang, Wen; Luo, Zong-Ping

    2015-01-01

    This study aims to assess the biomechanical properties of a novel fixation system (named AFRIF) and to compare it with other five different fixation techniques for quadrilateral plate fractures. This in vitro biomechanical experiment has shown that the multidirectional titanium fixation (MTF) and pelvic brim long screws fixation (PBSF) provided the strongest fixation for quadrilateral plate fracture; the better biomechanical performance of the AFRIF compared with the T-shaped plate fixation (TPF), L-shaped plate fixation (LPF), and H-shaped plate fixation (HPF); AFRIF gives reasonable stability of treatment for quadrilateral plate fracture and may offer a better solution for comminuted quadrilateral plate fractures or free floating medial wall fracture and be reliable in preventing protrusion of femoral head. PMID:25802849

  17. External Fixation: Principles and Applications.

    PubMed

    Bible, Jesse E; Mir, Hassan R

    2015-11-01

    The modularity and ease of application of modern external fixation has expanded its potential use in the management of fractures and other musculoskeletal conditions. In fracture care, it can be used for provisional and definitive fixation. Short-term provisional applications include "damage control" and periarticular fracture fixation. The risk:benefit ratio of added stability needs to be assessed with each fixator. Soft-tissue management is critical during pin insertion to lessen the risk of loosening and infection. Although provisional fixation is safe for early conversion to definitive fixation, several factors affect the timing of definitive surgery, including the initial injury, external fixator stability, infection, and the physiologic state of the patient. PMID:26306568

  18. 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.

  19. 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

  20. 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.

  1. [Fixation of cells for analysis by laser microdissection--comparative studies in forensic trace material].

    PubMed

    Fischer, Elisabeth J; Laberke, Patrick J; Kübler, Eric; Balitzki, Beate

    2012-01-01

    This paper is focused on the preparation of samples for laser microdissection (LM) in forensic casework. In forensic genetics, it is essential to preserve and separate cellular traces during sample preparation, as they are usually gathered in very small amounts and are often contaminated with undesired cells. This is made possible by laser microdissection, a technique developed to cut cells or tissue of a certain type from a microscopical specimen by UV laser and catapult them directly into a PCR reactor. This method minimizes the risk of getting inconclusive, mixed DNA profiles due to contamination by foreign DNA and also supplies information about the cellular origin of a DNA profile. A method for optimized fixation and staining of spermatozoa for laser microdissection was established. Four different fixation methods combined with two staining methods were tested on two different microscope slides. Moreover, the effect of a blocker pen to contain the specimen on the slide was investigated.

  2. A technique to re-establish dose distributions for previously treated brain cancer patients in external beam radiotherapy

    SciTech Connect

    Yue, Ning J.; Knisely, Jonathan; Studholme, Colin; Chen Zhe; Bond, James E.; Nath, Ravinder

    2004-03-31

    Tumor recurrences or new tumors may develop after irradiation of local lesion(s) in the brain, and additional radiotherapy treatments are often needed for previously treated patients. It is critical to re-establish the dose distributions delivered during the previous treatment in the current patient geometry, so that the previous dose distributions can be accurately taken into consideration in the design of the current treatment plan. The difficulty in re-establishing the previous treatment dose distributions in the current patient geometry arises from the fact that the patient position at the time of reirradiation is different from that at the previous treatment session. Simple re-entry of the previous isocenter coordinates, gantry, and couch and collimator angles into the new treatment plan would result in incorrect beam orientations relative to the new patient anatomy, and therefore incorrect display of the previous dose distributions on the current patient anatomy. To address this issue, a method has been developed so that the previous dose distributions can be accurately re-established in the framework of the current brain treatment. The method involves 3 matrix transformations: (1) transformation of beams from machine coordinate system to patient coordinate system in the previous treatment; (2) transformation of beams from patient coordinate system in the previous treatment to patient coordinate system in the current treatment; and (3) transformation of beams from patient coordinate system in the current treatment to machine coordinate system. The transformation matrices used in the second transformation are determined by registration using a mutual information-based algorithm with which the old and new computed tomography (CT) scan sets are registered automatically without human interpretation. A series of transformation matrices are derived to calculate the isocenter coordinates, the gantry, couch, and collimator angles of the beams for the previous

  3. Treatment of Midshaft Clavicle Fractures: Application of Local Autograft With Concurrent Plate Fixation.

    PubMed

    Slette, Erik L; Mikula, Jacob D; Turnbull, Travis Lee; Hackett, Thomas R

    2016-06-01

    Currently, open reduction-internal fixation using contoured plates or intramedullary nails is considered the standard operative treatment for midshaft clavicle fractures because of the immediate rigid stability provided by the fixation device. In addition, autologous iliac crest bone graft has proved to augment osteosynthesis during internal fixation of nonunion fractures through the release of osteogenic factors. The purpose of this article is to describe a surgical technique developed to reduce donor-site morbidity and improve functional and objective outcomes after open reduction-internal fixation with autologous bone graft placement through local autograft harvesting and concurrent plate fixation. PMID:27656378

  4. Retrospective comparison of percutaneous fixation and volar internal fixation of distal radius fractures.

    PubMed

    Lozano-Calderón, Santiago A; Doornberg, Job N; Ring, David

    2008-06-01

    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.

  5. Anatomic Study of Anterior Transdiscal Axial Screw Fixation for Subaxial Cervical Spine Injuries

    PubMed Central

    Ji, Wei; Zheng, Minghui; Qu, Dongbin; Zou, Lin; Chen, Yongquan; Chen, Jianting; Zhu, Qingan

    2016-01-01

    Abstract Anterior transdiscal axial screw (ATAS) fixation is an alternative or supplement to the plate and screw constructs for the upper cervical spine injury. However, no existing literatures clarified the anatomic feasibility of this technique for subaxial cervical spine. Therefore, the objective of this study was to evaluate the anatomical feasibility and to establish guidelines for the use of the ATAS fixation for the subaxial cervical spine injury. Fifty normal cervical spines had radiographs to determine the proposed screw trajectory (the screw length and insertion angle) and the interbody graft-related parameters (the disc height and depth, and the distance between anterior vertebral margin and the screw) for all levels of the subaxial cervical spine. Following screw insertion in 8 preserved human cadaver specimens, surgical simulation and dissection verified the feasibility and safety of the ATAS fixation. Radiographic measurements showed the mean axial screw length and cephalic incline angle of all levels were 41.2 mm and 25.2°, respectively. The suitable depth of the interbody graft was >11.7 mm (the distance between anterior vertebral margin and the screw), but <17.1 mm (disc depth). Except the axial screw length, increase in all the measurements was seen with level up to C5–C6 segment. Simulated procedure in the preserved specimens demonstrated that ATAS fixation could be successfully performed at C2–C3, C3–C4, C4–C5, and C5–C6 levels, but impossible at C6–C7 due to the obstacle of the sternum. All screws were placed accurately. None of the screws penetrated into the spinal canal and caused fractures determined by dissecting the specimens. The anterior transdiscal axial screw fixation, as an alternative or supplementary instrumentation for subaxial cervical spine injuries, is feasible and safe with meticulous surgical planning. PMID:27495016

  6. Bacterial alternative nitrogen fixation systems.

    PubMed

    Joerger, R D; Bishop, P E

    1988-01-01

    The introduction briefly reviews some of the salient features of the well-characterized conventional molybdo-enzyme system for N2 fixation. This is followed by a brief account of the discovery of an alternative N2 fixation system that does not require molybdenum in the N2-fixing bacterum Azotobacter vinelandii. The next section cites observations from the early literature on N2 fixation suggesting may not always require molybdenum. Next, recent evidence for an alternative N2 fixation system in A. vinelandii is discussed. A brief description of our discovery of an alternative nitrogenase which is not a molybdenum or vanadium enzyme is presented, followed by a summary of recent papers describing an alternative vanadium-containing nitrogenase. Available information on the genetics and regulation of alternative N2 fixation systems is discussed. Finally, the possible/probable presence of alternative N2 fixation systems in bacteria other than Azotobacter species is covered.

  7. Lateral Mass Fixation in the Subaxial Cervical Spine.

    PubMed

    Kurd, Mark F; Millhouse, Paul W; Schroeder, Gregory D; Kepler, Christopher K; Vaccaro, Alexander R

    2015-08-01

    The use of lateral mass screws and rods in the subaxial spine has become the standard method of fixation for posterior cervical spine fusions. Multiple techniques have been described for the placement of lateral mass screws, including the Magerl, the Anderson, and the An techniques. While these techniques are all slightly different, the overall goal is to obtain solid bony fixation while avoiding the neurovascular structures. The use of lateral mass screws has been shown to be a safe and effective technique for achieving a posterior cervical fusion.

  8. 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.

  9. Chromium and its speciation in water samples by HPLC/ICP-MS--technique establishing metrological traceability: a review since 2000.

    PubMed

    Markiewicz, Barbara; Komorowicz, Izabela; Sajnóg, Adam; Belter, Magdalena; Barałkiewicz, Danuta

    2015-01-01

    Chromium holds a special position among living organisms because depending on its species it can be either essential or toxic. Cr(VI) even at very low concentrations is harmful and carcinogenic, while Cr(III) is a necessary microelement for cellular metabolism. Therefore, a simple analysis of Cr concentration in collected samples will not be able to distinguish these differences effectively: for a proper chemical analysis we need to perform a reliable detection and quantification of Cr species. Separation and detection of chromium can be accomplished with high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC/ICP-MS) in a one-step. Our review assembles articles published since 2000 regarding chromium speciation in water samples with the use of HPLC/ICP-MS. It addresses the following issues: chromium chemistry, the possibilities of dealing with interferences, metrological aspects, analytical performance and speciated isotope dilution mass spectrometry (SIDMS) which is a definitive measurement method. The authors would like to advocate this hyphenated advanced technique as well as the metrological approach in speciation analysis of chromium.

  10. [Establishment of a method for HLA-DRB genotyping in cord blood by reverse dot-blot hybridization technique].

    PubMed

    Huang, Yi-Ning; Liao, Can; Tang, Xue-Wei; Li, Yan; Xie, Xing-Mei; Zeng, Rui-Ping

    2002-04-01

    The HLA system was discovered by virtue of the fact that it was polymorphic. The impetus for its discovery was the search for polymorphic antigens to match for transplantation, by analogy with the human red cell blood groups. The most usually DNA method of HLA typing is sequence specific oligonucleotides (SSO) and PCR sequence specific primers (SSP). SSO technique is perfectly suited for analyzing large number of samples, it is not suitable for individual or small numbers. The SSP method is ideal for typing individual samples, but it is costly and requires high capacity thermal cycles for larger numbers of samples. To set up a simple, quick, cheap and high resolution DNA method, were collected sixty-three cord blood samples from Guangzhou Cord Blood Bank, got DNA from blood by the traditional guanidine hydrochloride distillation method. Each sample was simultaneously typed by SSOP, PCR-SSP and reverse dot-blot hybridization (RDB) methods. All of typed is success. The results of three DNA methods are consistent each other. 60 HLA-DRB1 alleles could be accurately distinguished with the RDB method. Our results show that RDB method is a simple, quick, cheap and high resolution method for HLA-DRB types. It can be used in any HLA typing.

  11. Biological Nitrogen Fixation In Tropical Dry Forests Of Costa Rica

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Evidence suggests that tropical dry forests (TDF) are not nitrogen (N) deficient. This evidence includes: high losses of gaseous nitrogen during the rainy season, high ecosystem soil N stocks and high N concentrations in leaves and litterfall. Its been commonly hypothesized that biological nitrogen fixation is responsible for the high availability of N in tropical soils. However, the magnitude of this flux has rarely if ever been measured in tropical dry forests. Because of the high cost of fixing N and the ubiquity of N fixing legume trees in the TDF, at the individual tree level symbiotic fixation should be a strategy down-regulated by the plant. Our main goal was to determine the rates of and controls over symbiotic N fixation. We hypothesized that legume tree species employ a facultative strategy of nitrogen fixation and that this process responds to changes in light availability, soil moisture and nutrient supply. We tested this hypothesis both on naturally established trees in a forest and under controlled conditions in a shade house by estimating the quantities of N fixed annually using the 15N natural abundance method, counting nodules, and quantifying (field) or manipulating (shade house) the variation in important environmental variables (soil nutrients, soil moisture, and light). We found that in both in our shade house experiment and in the forest, nodulation varied among different legume species. For both settings, the 15N natural abundance approach successfully detected differences in nitrogen fixation among species. The legume species that we studied were able to regulate fixation depending on the environmental conditions. They showed to have different strategies of nitrogen fixation that follow a gradient of facultative to obligate fixation. Our data suggest that there exists a continuum of nitrogen fixation strategies among species. Any efforts to define tropical legume trees as a functional group need to incorporate this variation.

  12. Salivary bacterial fingerprints of established oral disease revealed by the Human Oral Microbe Identification using Next Generation Sequencing (HOMINGS) technique

    PubMed Central

    Belstrøm, Daniel; Paster, Bruce J.; Fiehn, Nils-Erik; Bardow, Allan; Holmstrup, Palle

    2016-01-01

    Background and objective The composition of the salivary microbiota, as determined using various molecular methods, has been reported to differentiate oral health from diseases. Thus, the purpose of this study was to utilize the newly developed molecular technique HOMINGS (Human Oral Microbe Identification using Next Generation Sequencing) for comparison of the salivary microbiota in patients with periodontitis, patients with dental caries, and orally healthy individuals. The hypothesis was that this method could add on to the existing knowledge on salivary bacterial profiles in oral health and disease. Design Stimulated saliva samples (n=30) were collected from 10 patients with untreated periodontitis, 10 patients with untreated dental caries, and 10 orally healthy individuals. Salivary microbiota was analyzed using HOMINGS and statistical analysis was performed using Kruskal–Wallis test with Benjamini–Hochberg's correction. Results From a total of 30 saliva samples, a mean number of probe targets of 205 (range 120–353) were identified, and a statistically significant higher mean number of targets was registered in samples from patients with periodontitis (mean 220, range 143–306) and dental caries (mean 221, range 165–353) as compared to orally healthy individuals (mean 174, range 120–260) (p=0.04 and p=0.04). Nine probe targets were identified with a different relative abundance between groups (p<0.05). Conclusions Cross-sectional comparison of salivary bacterial profiles by means of HOMINGS analysis showed that different salivary bacterial profiles were associated with oral health and disease. Future large-scale prospective studies are needed to evaluate if saliva-based screening for disease-associated oral bacterial profiles may be used for identification of patients at risk of acquiring periodontitis and dental caries. PMID:26782357

  13. 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

  14. Time Savings and Surgery Task Load Reduction in Open Intraperitoneal Onlay Mesh Fixation Procedure

    PubMed Central

    Roy, Sanjoy; Hammond, Jeffrey; Panish, Jessica; Shnoda, Pullen; Savidge, Sandy; Wilson, Mark

    2015-01-01

    Background. This study assessed the reduction in surgeon stress associated with savings in procedure time for mechanical fixation of an intraperitoneal onlay mesh (IPOM) compared to a traditional suture fixation in open ventral hernia repair. Study Design. Nine general surgeons performed 36 open IPOM fixation procedures in porcine model. Each surgeon conducted two mechanical (using ETHICON SECURESTRAPTM Open) and two suture fixation procedures. Fixation time was measured using a stopwatch, and related surgeon stress was assessed using the validated SURG-TLX questionnaire. T-tests were used to compare between-group differences, and a two-sided 95% confidence interval for the difference in stress levels was established using nonparametric methodology. Results. The mechanical fixation group demonstrated an 89.1% mean reduction in fixation time, as compared to the suture group (p < 0.00001). Surgeon stress scores measured using SURG-TLX were 55.5% lower in the mechanical compared to the suture fixation group (p < 0.001). Scores in five of the six sources of stress were significantly lower for mechanical fixation. Conclusions. Mechanical fixation with ETHICON SECURESTRAPTM Open demonstrated a significant reduction in fixation time and surgeon stress, which may translate into improved operating efficiency, improved performance, improved surgeon quality of life, and reduced overall costs of the procedure. PMID:26240834

  15. 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.

  16. Arthroscopic Fixation of Glenoid Rim Fractures After Reduction by Labral Repair.

    PubMed

    Voleti, Pramod B; Camp, Christopher L; Sinatro, Alec L; Dines, Joshua S

    2016-04-01

    Surgical fixation of displaced, intra-articular glenoid fractures represents a clinical challenge. These fractures have traditionally been treated through open approaches to the glenohumeral joint; however, the morbidity associated with open surgery may be reduced with arthroscopic techniques. Previously described arthroscopic methods commonly use clamps and/or Kirschner wires to obtain and maintain provisional fixation. We describe our technique for minimally invasive, arthroscopic fixation of glenoid rim fractures using labral repair as an indirect reduction maneuver, followed by final fixation with an extra-articular screw. This method is safe, efficient, and reliable, and it can be used to approach a variety of intra-articular glenoid fractures. PMID:27462537

  17. 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

  18. Primary Water Stress Corrosion Cracks in Nickel Alloy Dissimilar Metal Welds: Detection and Sizing Using Established and Emerging Nondestructive Examination Techniques

    SciTech Connect

    Braatz, Brett G.; Cumblidge, Stephen E.; Doctor, Steven R.; Prokofiev, Iouri

    2012-12-31

    The U.S. Nuclear Regulatory Commission has established the Program to Assess the Reliability of Emerging Nondestructive Techniques (PARENT) as a follow-on to the international cooperative Program for the Inspection of Nickel Alloy Components (PINC). The goal of PINC was to evaluate the capabilities of various nondestructive evaluation (NDE) techniques to detect and characterize surface-breaking primary water stress corrosion cracks in dissimilar-metal welds (DMW) in bottom-mounted instrumentation (BMI) penetrations and small-bore (≈400-mm diameter) piping components. A series of international blind round-robin tests were conducted by commercial and university inspection teams. Results from these tests showed that a combination of conventional and phased-array ultrasound techniques provided the highest performance for flaw detection and depth sizing in dissimilar metal piping welds. The effective detection of flaws in BMIs by eddy current and ultrasound shows that it may be possible to reliably inspect these components in the field. The goal of PARENT is to continue the work begun in PINC and apply the lessons learned to a series of open and blind international round-robin tests that will be conducted on a new set of piping components including large-bore (≈900-mm diameter) DMWs, small-bore DMWs, and BMIs. Open round-robin testing will engage universities and industry worldwide to investigate the reliability of emerging NDE techniques to detect and accurately size flaws having a wide range of lengths, depths, orientations, and locations. Blind round-robin testing will invite testing organizations worldwide, whose inspectors and procedures are certified by the standards for the nuclear industry in their respective countries, to investigate the ability of established NDE techniques to detect and size flaws whose characteristics range from easy to very difficult to detect and size. This paper presents highlights of PINC and reports on the plans and progress for

  19. Emotion words affect eye fixations during reading.

    PubMed

    Scott, Graham G; O'Donnell, Patrick J; Sereno, Sara C

    2012-05-01

    Emotion words are generally characterized as possessing high arousal and extreme valence and have typically been investigated in paradigms in which they are presented and measured as single words. This study examined whether a word's emotional qualities influenced the time spent viewing that word in the context of normal reading. Eye movements were monitored as participants read sentences containing an emotionally positive (e.g., lucky), negative (e.g., angry), or neutral (e.g., plain) word. Target word frequency (high or low) was additionally varied to help determine the temporal locus of emotion effects, with interactive results suggesting an early lexical locus of emotion processing. In general, measures of target fixation time demonstrated significant effects of emotion and frequency as well as an interaction. The interaction arose from differential effects with negative words that were dependent on word frequency. Fixation times on emotion words (positive or negative) were consistently faster than those on neutral words with one exception-high-frequency negative words were read no faster than their neutral counterparts. These effects emerged in the earliest eye movement measures, namely, first and single fixation duration, suggesting that emotionality, as defined by arousal and valence, modulates lexical processing. Possible mechanisms involved in processing emotion words are discussed, including automatic vigilance and desensitization, both of which imply a key role for word frequency. Finally, it is important that early lexical effects of emotion processing can be established within the ecologically valid context of fluent reading.

  20. Biomechanical Concepts for Fracture Fixation.

    PubMed

    Bottlang, Michael; Schemitsch, Christine E; Nauth, Aaron; Routt, Milton; Egol, Kenneth A; Cook, Gillian E; Schemitsch, Emil H

    2015-12-01

    Application of the correct fixation construct is critical for fracture healing and long-term stability; however, it is a complex issue with numerous significant factors. This review describes a number of common fracture types and evaluates their currently available fracture fixation constructs. In the setting of complex elbow instability, stable fixation or radial head replacement with an appropriately sized implant in conjunction with ligamentous repair is required to restore stability. For unstable sacral fractures with vertical or multiplanar instabilities, "standard" iliosacral screw fixation is not sufficient. Periprosthetic femur fractures, in particular Vancouver B1 fractures, have increased stability when using 90/90 fixation versus a single locking plate. Far cortical locking combines the concept of dynamization with locked plating to achieve superior healing of a distal femur fracture. Finally, there is no ideal construct for syndesmotic fracture stabilization; however, these fractures should be fixed using a device that allows for sufficient motion in the syndesmosis. In general, orthopaedic surgeons should select a fracture fixation construct that restores stability and promotes healing at the fracture site, while reducing the potential for fixation failure.

  1. Lagged Syndesmotic Fixation: Our Clinical Experience.

    PubMed

    Kwaadu, Kwasi Yiadom; Fleming, Justin James; Salmon, Trudy

    2015-01-01

    Ankle fractures are very common, and although algorithms are in place for osseous management, consensus has not been reached regarding treatment of associated ligamentous injuries. Although tibiofibular syndesmotic stabilization can be done using different forms of fixation, the biomedical literature has long emphasized the risk of long-term restriction of ankle mobility with the use of lagged transfixation. However, when reduction cannot be maintained with positional fixation, we found that lagging the syndesmotic screw helped to maintain the reduction without causing functional restriction. In this report, we describe our experience with patients who had undergone lagged tibiofibular transfixation and were available for short- to intermediate-term follow-up to assess ankle function. A total of 31 patients (32.63% of 95 consecutive patients) were available at a mean of 34.87 (range 18 to 52) months to complete the American Orthopedic Foot and Ankle Society ankle-hindfoot questionnaire. The mean score was 88.38 (range 42 to 100) points at a mean follow-up interval of 34.87 (range 18 to 52) months. Of 31 patients, 19 had an AOFAS score of 90 points, 9 an AOFAS score of 80 to 89 points, 2 an AOFAS score of 60 to 69 points, and 1 an AOFAS score of <60 points. Because all syndesmotic screws were placed using the lag technique, unrestricted motion compared with the uninjured limb was used as the endpoint. All subjects had unrestricted motion compared with the uninjured limb, refuting the assertion that lagged syndesmotic screw fixation confers more restriction in ankle kinematics than positional syndesmotic fixation. PMID:25736445

  2. Lagged Syndesmotic Fixation: Our Clinical Experience.

    PubMed

    Kwaadu, Kwasi Yiadom; Fleming, Justin James; Salmon, Trudy

    2015-01-01

    Ankle fractures are very common, and although algorithms are in place for osseous management, consensus has not been reached regarding treatment of associated ligamentous injuries. Although tibiofibular syndesmotic stabilization can be done using different forms of fixation, the biomedical literature has long emphasized the risk of long-term restriction of ankle mobility with the use of lagged transfixation. However, when reduction cannot be maintained with positional fixation, we found that lagging the syndesmotic screw helped to maintain the reduction without causing functional restriction. In this report, we describe our experience with patients who had undergone lagged tibiofibular transfixation and were available for short- to intermediate-term follow-up to assess ankle function. A total of 31 patients (32.63% of 95 consecutive patients) were available at a mean of 34.87 (range 18 to 52) months to complete the American Orthopedic Foot and Ankle Society ankle-hindfoot questionnaire. The mean score was 88.38 (range 42 to 100) points at a mean follow-up interval of 34.87 (range 18 to 52) months. Of 31 patients, 19 had an AOFAS score of 90 points, 9 an AOFAS score of 80 to 89 points, 2 an AOFAS score of 60 to 69 points, and 1 an AOFAS score of <60 points. Because all syndesmotic screws were placed using the lag technique, unrestricted motion compared with the uninjured limb was used as the endpoint. All subjects had unrestricted motion compared with the uninjured limb, refuting the assertion that lagged syndesmotic screw fixation confers more restriction in ankle kinematics than positional syndesmotic fixation.

  3. Arthroscopic Fixation of Tibial Spine Avulsion Fracture in Open Physis

    PubMed Central

    Chouhan, Varun

    2016-01-01

    Introduction: Arthroscopic fixation of tibial spine fracture in patients with open physis without damaging the growth plate is very important. We have described a very simple and effective technique for the first time in this article. Case report: A 16-year-old boy sustained avulsion fractures of tibial spine while playing. He was treated arthroscopically with excellent results. Conclusion: Arthroscopic fixation of tibial spine fracture in patients with open physis with two cannulated screws perpendicular to each other is a very simple technique providing strong construct, and allowing early mobilization without risk of damage to the growth plate. PMID:27703945

  4. 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... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1290 Fixation device. (a) Identification. A fixation device is an AC-powered device intended for use as a fixation target for the patient...

  5. 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)

  6. Changes in biomolecular profile in a single nucleolus during cell fixation.

    PubMed

    Kuzmin, Andrey N; Pliss, Artem; Prasad, Paras N

    2014-11-01

    Fixation of biological sample is an essential technique applied in order to "freeze" in time the intracellular molecular content. However, fixation induces changes of the cellular molecular structure, which mask physiological distribution of biomolecules and bias interpretation of results. Accurate, sensitive, and comprehensive characterization of changes in biomolecular composition, occurring during fixation, is crucial for proper analysis of experimental data. Here we apply biomolecular component analysis for Raman spectra measured in the same nucleoli of HeLa cells before and after fixation by either formaldehyde solution or by chilled ethanol. It is found that fixation in formaldehyde does not strongly affect the Raman spectra of nucleolar biomolecular components, but may significantly decrease the nucleolar RNA concentration. At the same time, ethanol fixation leads to a proportional increase (up to 40%) in concentrations of nucleolar proteins and RNA, most likely due to cell shrinkage occurring in the presence of coagulant fixative. Ethanol fixation also triggers changes in composition of nucleolar proteome, as indicated by an overall reduction of the α-helical structure of proteins and increase in the concentration of proteins containing the β-sheet conformation. We conclude that cross-linking fixation is a more appropriate protocol for mapping of proteins in situ. At the same time, ethanol fixation is preferential for studies of RNA-containing macromolecules. We supplemented our quantitative Raman spectroscopic measurements with mapping of the protein and lipid macromolecular groups in live and fixed cells using coherent anti-Stokes Raman scattering nonlinear optical imaging.

  7. The use of rigid internal fixation in the surgical management of cervical spondylosis.

    PubMed

    Kwon, Brian K; Vaccaro, Alexander R; Grauer, Jonathan N; Beiner, John M

    2007-01-01

    In the surgical management of cervical spondylosis, the application of rigid internal fixation can enhance the immediate stability of the cervical spine. The sophistication of such internal fixation systems and the indications for their use are continuously evolving. A sound understanding of regional anatomy, biomechanics, and kinematics within the cervical spine is essential for the safe and effective application of internal fixation. Numerous options currently exist for anterior cervical plating systems; some lock the screws to the plate rigidly (constrained), whereas others allow for some rotational or translational motion between the screw and plate (semiconstrained). The role of anterior fixation in single and multilevel fusions is still the subject of some controversy. Long anterior cervical reconstructions may require additional posterior fixation to reliably promote fusion. Rigid fixation in the posterior cervical spine can be achieved with lateral mass screws or pedicle screws. Although lateral mass screws provide excellent fixation within the subaxial cervical spine, the regional anatomy of C2 and C7 often make it difficult to place such screws, and pedicle screws at these levels are advocated. Pedicle screws achieve fixation into both the anterior and posterior column and are arguably the most stable form of rigid internal fixation within the cervical spine. Familiarity with these internal fixation techniques can be an extremely valuable tool for the spine surgeon managing these degenerative disorders of the cervical spine.

  8. Percutaneous Lumbopelvic Fixation for Reduction and Stabilization of Sacral Fractures With Spinopelvic Dissociation Patterns

    PubMed Central

    Quinnan, Stephen M.

    2016-01-01

    Summary: Sacral fractures that result in spinopelvic dissociation are unstable injuries that are often treated surgically, with iliosacral screw fixation and/or lumbopelvic fixation from L4 to the pelvis. Open lumbopelvic fixation allows for direct fracture reduction and immediate postoperative weight bearing, but is associated with a relatively high wound complication rate. Open surgery often takes several hours and can be associated with significant blood loss, and therefore may not be well tolerated physiologically in these patients who often have multiple injuries. We developed a percutaneous lumbopelvic reduction and fixation technique to address these issues. PMID:26894767

  9. An injectable cementing screw for fixation in osteoporotic bone.

    PubMed

    McKoy, B E; An, Y H

    2000-01-01

    With the aging population, osteoporosis and osteoporotic fractures are becoming more prevalent. Adequate screw fixation in this type of bone is difficult. Screws are often cemented in bone to help obtain purchase. However, current cementing techniques do not ensure implant stability. Here we present a new cannulated screw with side ports that can be injected with polymethylmethacylate (PMMA) for fixation in osteoporotic bone. We compared the ultimate holding power of this cannulated screw injected with PMMA to a solid screw with the same dimensions secured with PMMA by the standard technique. Both screws were placed into embalmed and fresh frozen lumbar vertebral bodies and pulled out using a mechanical testing system. The cannulated screw had a 278% greater holding power compared to the standard screw (p < 0.006). The cannulated screw provided a significant increase in holding power in osteoporotic bone. This novel screw is promising for fixation in osteoporotic bone and warrants clinical evaluation.

  10. Tips of the trade #38. The Herbert screw in closed reduction and internal fixation of the Jones fracture.

    PubMed

    Traina, S M; McElhinney, J P

    1991-08-01

    A technique of using a cannulated Herbert screw is presented for addressing the troublesome Jones fracture. This closed intramedullary fixation technique allows early healing without many of the screw head problems encountered in the more traditional AO screw techniques.

  11. Denitrification and N2 fixation in the Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Deutsch, Curtis; Gruber, Nicolas; Key, Robert M.; Sarmiento, Jorge L.; Ganachaud, Alexandre

    2001-06-01

    We establish the fixed nitrogen budget of the Pacific Ocean based on nutrient fields from the recently completed World Ocean Circulation Experiment (WOCE). The budget includes denitrification in the water column and sediments, nitrogen fixation, atmospheric and riverine inputs, and nitrogen divergence due to the large-scale circulation. A water column denitrification rate of 48±5 Tg N yr -1 is calculated for the Eastern Tropical Pacific using N* [Gruber and Sarmiento, 1997] and water mass age tracers. On the basis of rates in the literature, we estimate sedimentary denitrification to remove an additional 15±3 Tg N yr-1. We then calculate the total nitrogen divergence due to the large scale circulation through the basin, composed of flows through a zonal transect at 32°S, and through the Indonesian and Bering straits. Adding atmospheric deposition and riverine fluxes results in a net divergence of nitrogen from the basin of -4±12 Tg N yr-1. Pacific nitrogen fixation can be extracted as a residual component of the total budget, assuming steady state. We find that nitrogen fixation would have to contribute 59±14 Tg N yr-1 in order to balance the Pacific nitrogen budget. This result is consistent with the tentative global extrapolations of Gruber and Sarmiento [1997], based on nitrogen fixation rates estimated for the North Atlantic. Our estimated mean areal fixation rate is within the range of direct and geochemical rate estimates from a single location near Hawaii [Karl et al., 1997]. Pacific nitrogen fixation occurs primarily in the western part of the subtropical gyres where elevated N* signals are found. These regions are also supplied with significant amounts of iron via atmospheric dust deposition, lending qualitative support to the hypothesis that nitrogen fixation is regulated in part by iron suppy.

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

    PubMed

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

    2016-02-01

    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.

  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. Hiatus Hernia Repair with Bilateral Oesophageal Fixation.

    PubMed

    Mendis, Rajith; Cheung, Caran; 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

  15. Effects of tissue fixation on coherent anti-Stokes Raman scattering images of brain

    NASA Astrophysics Data System (ADS)

    Galli, Roberta; Uckermann, Ortrud; Koch, Edmund; Schackert, Gabriele; Kirsch, Matthias; Steiner, Gerald

    2014-07-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy is an emerging multiphoton technique for the label-free histopathology of the central nervous system, by imaging the lipid content within the tissue. In order to apply the technique on standard histology sections, it is important to know the effects of tissue fixation on the CARS image. Here, we report the effects of two common fixation methods, namely with formalin and methanol-acetone, on mouse brain and human glioblastoma tissue. The variations induced by fixation on the CARS contrast and intensity were compared and interpreted using Raman microspectroscopy. The results show that, whenever unfixed cryosections cannot be used, fixation with formalin constitutes an alternative which does not deteriorate substantially the contrast generated by the different brain structures in the CARS image. Fixation with methanol-acetone strongly modifies the tissue lipid content and is therefore incompatible with the CARS imaging.

  16. Dynamic Distraction External Fixation for Contracture of the Metacarpophalangeal Joint.

    PubMed

    Seigerman, Daniel A; Tan, Virak

    2015-12-01

    Metacarpophalangeal (MP) joint contractures are common after traumatic injury, and can be difficult to manage. After surgical capsulectomy, it remains challenging to maintain motion that was obtained at the time of surgery. Our group uses a novel, prefabricated digital external fixator to provide both distraction, and motion therapy across the MP joint after surgical treatment of MP contracture. The purpose of this technique is to demonstrate the effectiveness of an adjunctive dynamic distraction external fixator for the maintenance of joint motion after surgical treatment of MP contractures of the border digits. PMID:26280472

  17. Alkaline fixation drastically improves the signal of in situ hybridization

    PubMed Central

    Basyuk, Eugenia; Bertrand, Edouard; Journot, Laurent

    2000-01-01

    In situ hybridization (ISH) is widely used to detect DNA and RNA sequences within the cell and tissue sections. The important step in performing this technique is tissue fixation. We investigated the influence of the pH of the fixative on the outcome of ISH. Our studies indicate that alkaline formaldehyde dramatically increases the ISH signal with RNA probes. The increase in signal was observed for detection of low as well as for high abundance messages. The sensitivity of the method was increased 5- to 6-fold. PMID:10773094

  18. Modified Technique of Tibial Tuberosity Transfer.

    PubMed

    Pemmaraju, Gopalakrishna; Raad, Abbas; Kotecha, Amit; Chugh, Sanjiv; Mughal, Ejaz

    2015-08-01

    Tibial tuberosity transfer is a well-established procedure in the treatment of patellar instability and in selected cases of anterior knee pain. Several techniques have been advocated in the literature. Some of the common complications associated with this procedure have been pain and discomfort due to prominent screw heads, necessitating their removal; nonunion and delayed union of the osteotomy; and failure of fixation. Tibial fractures have also been reported in some case reports. We present our technique of tibial tuberosity transfer using two 4-mm cannulated screws for stabilization of the tuberosity fragment. We have used this technique either for isolated tibial tuberosity transfer or as part of a combined procedure along with medial patellofemoral ligament reconstruction in treating patellar instability. Using this technique, we have encountered no patients with wound problems, nonunion, delayed union, or loss of fixation and only 1 patient with a metal work problem needing a second procedure for its removal. We attribute our good outcomes to the preservation of the soft-tissue attachments to the tuberosity fragment; minimal soft-tissue dissection, which allows rapid bony consolidation of the osteotomy, which in turn allows accelerated rehabilitation; and the use of 4-mm cannulated screws for fixation of the osteotomy, minimizing the potential for metal work problems. PMID:26759775

  19. Polymer cable/grip-plate system with locking screws for stable fixation to promote healing of trochanteric osteotomies or fractures in revision total hip arthroplasty.

    PubMed

    Berend, Keith R; Willen, Jacob L; Morris, Michael J; Adams, Joanne B; Lombardi, Adolph V

    2014-11-01

    Multiple methods have been proposed to establish stable fixation to promote healing of trochanteric osteotomies or fractures in revision total hip arthroplasty (revTHA), from wiring techniques through cable-plate systems with or without supplemental locking screws. The purpose of this study is to report the clinical results of a single cable-plate system with locked screw fixation in revTHA. Between 2009 and 2012, 27 grip-plates (Supercable® System, Kinamed Inc., Camarillo, CA) were used in 26 patients in 27 revTHA procedures. Utilization was 12 1-hole (50 mm) grip-plates, 10 2-hole (135 mm) grip-plates, four 4-hole (190 mm) grip-plates, and one 6-hole (245 mm) grip-plate. There were 14 women and 12 men. Age averaged 63.2 years and BMI averaged 29.4 kg/m2. At average 2.5 year follow-up, grip-plate fixation was considered successful in 22 hips (81%) with five failures. Three failures consisted of 50 mm/short grip-plates used in one trochanteric slide, and two intraoperative trochanteric fractures during revTHA. The two additional failures were related to pre-revision trochanteric avulsion from bony necrosis of the proximal femur. An additional three grip-plates were removed electively for soft-tissue irritation and pain but with successful fixation and bony healing. Thus 70% of hips were free of reoperation related to the grip-plate. All other hips had successful fixation and the grip-plate was not symptomatic. In this study, the cable-grip system and isoelastic Supercables provided reliable fixation for adequate healing of difficult ETO and trochanteric fractures with an 81% rate of mechanical success with radiographic and clinical healing observed.

  20. Nitrogen fixation in the mucus of Red Sea corals.

    PubMed

    Grover, Renaud; Ferrier-Pagès, Christine; Maguer, Jean-François; Ezzat, Leila; Fine, Maoz

    2014-11-15

    Scleractinian corals are essential constituents of tropical reef ecological diversity. They live in close association with diazotrophs [dinitrogen (N2)-fixing microbes], which can fix high rates of N2. Whether corals benefit from this extrinsic nitrogen source is still under debate. Until now, N2 fixation rates have been indirectly estimated using the acetylene reduction assay, which does not permit assessment of the amount of nitrogen incorporated into the different compartments of the coral holobiont. In the present study, the (15)N2 technique was applied for the first time on three Red Sea coral species. Significant (15)N enrichment was measured in particles released by corals to the surrounding seawater. N2 fixation rates were species specific and as high as 1.6-2 ng N day(-1) l(-1). However, no significant enrichment was measured in the symbiotic dinoflagellates or the coral host tissues, suggesting that corals do not benefit from diazotrophic N2 fixation.

  1. Hydroponic Growth and the Nondestructive Assay for Dinitrogen Fixation 1

    PubMed Central

    Imsande, John; Ralston, Edward J.

    1981-01-01

    Hydroponic growth medium must be well buffered if it is to support sustained plant growth. Although 1.0 millimolar phosphate is commonly used as a buffer for hydroponic growth media, at that concentration it is generally toxic to a soybean plant that derives its nitrogen solely from dinitrogen fixation. On the other hand, we show that 1.0 to 2.0 millimolar 2-(N-morpholino)ethanesulfonic acid, pKa 6.1, has excellent buffering capacity, and it neither interferes with nor contributes nutritionally to soybean plant growth. Furthermore, it neither impedes nodulation nor the assay of dinitrogen fixation. Hence, soybean plants grown hydroponically on a medium supplemented with 1.0 to 2.0 millimolar 2-(N-morpholino)ethanesulfonic acid and 0.1 millimolar phosphate achieve an excellent rate of growth and, in the absence of added fixed nitrogen, attain a very high rate of dinitrogen fixation. Combining the concept of hydroponic growth and the sensitive acetylene reduction technique, we have devised a simple, rapid, reproducible assay procedure whereby the rate of dinitrogen fixation by individual plants can be measured throughout the lifetime of those plants. The rate of dinitrogen fixation as measured by the nondestructive acetylene reduction procedure is shown to be approximately equal to the rate of total plant nitrogen accumulation as measured by Kjeldahl analysis. Because of the simplicity of the procedure, one investigator can readily assay 50 plants individually per day. PMID:16662112

  2. Effects of fixative and fixation time on the extraction and polymerase chain reaction amplification of RNA from paraffin-embedded tissue. Comparison of two housekeeping gene mRNA controls.

    PubMed

    Foss, R D; Guha-Thakurta, N; Conran, R M; Gutman, P

    1994-09-01

    A number of reports have indicated that RNA recovered from paraffin-embedded tissue can be used as a substrate in the polymerase chain reaction (PCR). Although it is established that RNA in paraffin-embedded tissue undergoes significant degradation, the specific contributions of different fixatives and fixation times to this degradation are not known. Mouse splenic tissue was harvested and fixed immediately for 2, 8, or 24 h in either formalin, Omnifix II, or Carnoy's fixative and then processed and embedded in paraffin. RNA was extracted from deparaffinized cubes of tissue using an adaptation of the technique described by Chomczynski and Sacchi. RNA was reverse transcribed using a random hexamer primed reaction. PCR amplification for cDNAs of the housekeeping genes glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and hypoxanthine phosphoribosyltransferase (HPRT) mRNAs was then performed. Although GAPDH amplification is used routinely on fresh and frozen tissues, we show that the presence of DNA contamination in the RNA preparations limits its usefulness in paraffin-embedded tissue. Amplifiable HPRT mRNA sequences were detected in nine of 12 samples fixed in Omnifix II, in four of 12 samples fixed in Carnoy's fixative, and in none of 12 formalin-fixed samples. Because of primer selection to preclude amplification of genomic HPRT, DNA contamination is not an issue when HPRT is amplified. Thus, HPRT represents the control system of choice for the evaluation of RNA in PET. The techniques described provide a rapid, uniform, and reproducible method of obtaining RNA from PET for molecular analysis, but they indicate limited utility for retrospective analysis of archival tissues. PMID:7981889

  3. Complications in operative fixation of calcaneal fractures

    PubMed Central

    Li, Ying; Bao, Rong-Hua; Jiang, Zhi-Qiang; Wu, Huo-Yan

    2016-01-01

    Objective: The purpose of this study focused on a number of factors that have been implicated in calcaneal complications and find the incidence of wound complications. Methods: This was a retrospective study. A total of 162 patients (176 feet) who underwent calcaneal fractures between 2007 and 2012 were included. The patient’s personal details, age, time from injury to surgery, cause of injury, type of fracture, operative details, operating and tourniquet times were collected from hospital computers and paper records. Evidence of complications including wound infection, wound necrosis, pain, malunion, nonunion, impingement, loss of fixation, ect were studied. Results: Forty-seven of one hundred and seventy-six fractures (26.704%) had complications, wound infection was noted in seven fractures (3.977%), twelve fractures developed necrosis (6.818%), 14 fractures (7.955%) developed pain. Malunion was found in five fractures (2.841%), nonunion in two fractures (1.136%) and loss of fixation in four fractures (2.272%). Three neurologic injury was also seen in our study (1.705%). Operating time, time from injury to surgery and type of fracture had some association with complications in operative fixation of calcaneal fractures, which showed a statistically significant improvement (P=0.000, 0.031, 0.020, respectively), but there were no evidence that age and tourniquet time affect the incidence of complication after calcaneal fracture surgery (P=0.119, 0.682, respectively). Conclusions: Despite developments in the surgical treatment of calcaneal fracture, wound complications still remain inevitable. Advanced imaging techniques, less invasive surgical procedures, wealth of anatomical knowledge, surgical experience and better postoperative care should be ensured.

  4. Complications in operative fixation of calcaneal fractures

    PubMed Central

    Li, Ying; Bao, Rong-Hua; Jiang, Zhi-Qiang; Wu, Huo-Yan

    2016-01-01

    Objective: The purpose of this study focused on a number of factors that have been implicated in calcaneal complications and find the incidence of wound complications. Methods: This was a retrospective study. A total of 162 patients (176 feet) who underwent calcaneal fractures between 2007 and 2012 were included. The patient’s personal details, age, time from injury to surgery, cause of injury, type of fracture, operative details, operating and tourniquet times were collected from hospital computers and paper records. Evidence of complications including wound infection, wound necrosis, pain, malunion, nonunion, impingement, loss of fixation, ect were studied. Results: Forty-seven of one hundred and seventy-six fractures (26.704%) had complications, wound infection was noted in seven fractures (3.977%), twelve fractures developed necrosis (6.818%), 14 fractures (7.955%) developed pain. Malunion was found in five fractures (2.841%), nonunion in two fractures (1.136%) and loss of fixation in four fractures (2.272%). Three neurologic injury was also seen in our study (1.705%). Operating time, time from injury to surgery and type of fracture had some association with complications in operative fixation of calcaneal fractures, which showed a statistically significant improvement (P=0.000, 0.031, 0.020, respectively), but there were no evidence that age and tourniquet time affect the incidence of complication after calcaneal fracture surgery (P=0.119, 0.682, respectively). Conclusions: Despite developments in the surgical treatment of calcaneal fracture, wound complications still remain inevitable. Advanced imaging techniques, less invasive surgical procedures, wealth of anatomical knowledge, surgical experience and better postoperative care should be ensured. PMID:27648028

  5. CO(2) Fixation in Opuntia Roots.

    PubMed

    Ting, I P; Dugger, W M

    1966-03-01

    Nonautotrophic CO(2) metabolism in Opuntia echinocarpa roots was studied with techniques of manometry and radiometry. The roots were grown in a one-quarter strength nutrient solution for several days; the distal 2 cm was used for physiological studies. The roots assimilated significant quantities of (14)CO(2) and appeared to show a crassulacean-type acid metabolism with respect to quality and quantity. Most of the (14)C activity was associated with the distal portion of the elongating root indicating correlation with metabolic activity. The (14)CO(2) assimilation was comparable to a crassulacean leaf succulent, but 3 times greater than that found for stem tissue of the same Opuntia species.The rates of O(2) and CO(2) exchange and estimated CO(2) fixation were 180, 123, and 57 mul/g per hour. A respiratory quotient of 0.66 was found.The products of (14)CO(2) fixation were similar in most respects to reported experiments with leaf succulents. Equilibration of the predominant malic acid with isocitric, succinic, and fumaric acids was not evident. The latter observation was interpreted as metabolic isolation of the fixation products rather than poor citric acid cycle activity.A rapid turnover of the fixed (14)CO(2) was measured by following decarboxlyation kinetics and by product analysis after a postincubation period. The first order rate constant for the steady state release was 4.4 x 10(-3) min(-1) with a half-time of 157.5 minutes. Amino acids decayed at a more rapid rate than organic acids.

  6. Phase-contrast Hounsfield units of fixated and non-fixated soft-tissue samples

    SciTech Connect

    Willner, Marian; Fior, Gabriel; Marschner, Mathias; Birnbacher, Lorenz; Schock, Jonathan; Braun, Christian; Fingerle, Alexander A.; Noël, Peter B.; Rummeny, Ernst J.; Pfeiffer, Franz; Herzen, Julia; Rozhkova, Elena A.

    2015-08-31

    X-ray phase-contrast imaging is a novel technology that achieves high soft-tissue contrast. Although its clinical impact is still under investigation, the technique may potentially improve clinical diagnostics. In conventional attenuation-based X-ray computed tomography, radiological diagnostics are quantified by Hounsfield units. Corresponding Hounsfield units for phase-contrast imaging have been recently introduced, enabling a setup-independent comparison and standardized interpretation of imaging results. Thus far, the experimental values of few tissue types have been reported; these values have been determined from fixated tissue samples. This study presents phase-contrast Hounsfield units for various types of non-fixated human soft tissues. A large variety of tissue specimens ranging from adipose, muscle and connective tissues to liver, kidney and pancreas tissues were imaged by a grating interferometer with a rotating-anode X-ray tube and a photon-counting detector. In addition, we investigated the effects of formalin fixation on the quantitative phase-contrast imaging results.

  7. Phase-contrast Hounsfield units of fixated and non-fixated soft-tissue samples

    DOE PAGES

    Willner, Marian; Fior, Gabriel; Marschner, Mathias; Birnbacher, Lorenz; Schock, Jonathan; Braun, Christian; Fingerle, Alexander A.; Noël, Peter B.; Rummeny, Ernst J.; Pfeiffer, Franz; et al

    2015-08-31

    X-ray phase-contrast imaging is a novel technology that achieves high soft-tissue contrast. Although its clinical impact is still under investigation, the technique may potentially improve clinical diagnostics. In conventional attenuation-based X-ray computed tomography, radiological diagnostics are quantified by Hounsfield units. Corresponding Hounsfield units for phase-contrast imaging have been recently introduced, enabling a setup-independent comparison and standardized interpretation of imaging results. Thus far, the experimental values of few tissue types have been reported; these values have been determined from fixated tissue samples. This study presents phase-contrast Hounsfield units for various types of non-fixated human soft tissues. A large variety of tissuemore » specimens ranging from adipose, muscle and connective tissues to liver, kidney and pancreas tissues were imaged by a grating interferometer with a rotating-anode X-ray tube and a photon-counting detector. In addition, we investigated the effects of formalin fixation on the quantitative phase-contrast imaging results.« less

  8. 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.

  9. 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.

  10. The influence of alternative plant propagation and stand establishment techniques on survival and growth of eastern cottonwood (Populus deltoides Bartr.) clones.

    SciTech Connect

    Kaczmarek, Donald J.; et. al.,

    2014-02-09

    Four eastern cottonwood clones, including standard operational clone ST66 and three advanced clonal selections were produced and included in a test utilizing five different plant propagation methods. Despite relatively large first-year growth differences among clones, all clones demonstrated similar responses to the treatments and clone 9 cutting treatment interactions were generally non-significant. The effects of changing cutting lengths are consistent with previous studies which indicated the potential for increased plant survival and growth with increased cutting lengths. Differences in stored carbohydrate reserves alone do not appear to completely control first-year growth and development of cuttings. First-year growth of 51 cm long cuttings planted 30.5 cm deep was greater than the same cuttings planted 48 cm deep. Stem form of plants derived from whip-tip propagation did not differ from plants derived from standard, unrooted cuttings. This propagation method offers the potential of far greater production capacity from a cutting orchard and rapid bulk-up of new or limited clones. Stand uniformity assessments suggest that surviving trees of each individual cutting treatment exhibit similar levels of growth variation. Optimization of plantation establishment techniques has the potential to increase growth of young Populus plantations.

  11. Complications of rigid internal fixation.

    PubMed

    Campbell, Chris A; Lin, Kant Y

    2009-03-01

    Over the past 20 years, there have been many advances in the development of bone fixation systems used in the practice of craniomaxillofacial surgery. As surgical practices have evolved, the complications of each technologic advance have changed accordingly. Interfragmentary instability of interosseous wiring has been replaced by the risk of exposure, infection, and palpability of plate and screw fixation systems. The improved rigidity of plate fixation requires anatomic alignment of fracture fragments. Failure to obtain proper alignment has led to the phenomenon known as "open internal fixation" of fracture fragments without proper reduction. The size of the plates has decreased to minimize palpability and exposure. However limitations in their application have been encountered due to the physiologic forces of the muscles of mastication and bone healing. In the pediatric population, the long-standing presence of plates in the cranial vault resulted in reports of transcranial migration and growth restriction. These findings led to the development of resorbable plating systems, which are associated with self-limited plate palpability and soft tissue inflammatory reactions. Any rigid system including these produces growth restriction in varying amounts. In this discussion, we review the reported complication rates of miniplating and microplating systems as well as absorptive plating systems in elective and traumatic craniofacial surgery.

  12. 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

  13. Binocular Fixation Disparity in Single Word Displays

    ERIC Educational Resources Information Center

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

    2009-01-01

    It has been claimed that the recognition of words displayed in isolation is affected by the precise location at which they are fixated. However, this putative role for fixation location has yet to be reconciled with the finding from reading research that binocular fixations are often misaligned and, therefore, more than 1 location in a word is…

  14. Shift of visual fixation dependent on background illumination.

    PubMed

    Barash, S; Melikyan, A; Sivakov, A; Tauber, M

    1998-05-01

    Visual fixation, the act of maintaining the eyes directed toward a location of interest, is a highly skilled behavior necessary for high-level vision in primates. In spite of its significance, visual fixation is not well understood; it is not even clear what attributes of the visual input are used to control fixation. Here we show, in four Macaca fascicularis monkeys, that the position the eyes assume during fixation depends on the luminance of the background. Dark background yields fixation positions that are shifted upward with respect to the fixation positions obtained with a dimly illuminated, featureless background. This phenomenon was observed previously in a nutshell by Snodderly; here first we rigorously establish its existence by testing proper controls. We then study the properties of this upshift of the fixation position. We show that, although the size of the upshift varies between monkeys, for all monkeys the upshift is larger than the radius of the fovea. Hence, if the background is dim, the eyes are positioned during fixation so that the target does not fall on the fovea. The size of the upshift remains almost unchanged while the eyes fixate at different orbital positions; thus the upshift is not caused by orbital mechanics. The upshift clearly is present even at the first days of training, but with additional training in fixation with dark background, the upshift increases in size. The upshift rotates with the head. The upshift increases gradually with decreasing levels of background luminosity. Luminosity, not visual contrast, is indeed the primary variable determining the size of the upshift. The contribution of a unit area of the retina to the upshift decreases as inverse square root of distance from the target; therefore, it is the perifoveal region of the retina that mostly contributes to the upshift, while the far periphery has little influence. The upshift can be induced or be canceled in the midst of a fixation by changing the background

  15. Visual responses of neurones in cat superior colliculus in relation to fixation of targets.

    PubMed Central

    Peck, C K

    1989-01-01

    1. Visually elicited discharges were recorded from single cells in the intermediate and deep layers of the superior colliculus of alert, trained cats. With the behavioural protocols used, vigorous and consistent visual responses to the onset and offset of small, stationary targets were encountered in all layers of the colliculus. In addition, the responses of many cells depended on the behavioural context in which the response occurred. Specifically, thirty-nine cells were encountered in which discharge was contingent upon prolonged fixation of the visual stimulus. Thirty of these were located in the intermediate and deep layers and comprised 22% of the 134 isolated cells which were not related to saccadic eye movement. 2. Fixation-related cells showed sustained increases or decreases in firing during fixation of a visual target. Responses to presentation of a visual target at the same retinal location, without active fixation by the animal, were either absent, much weaker, or had extremely variable latencies. 3. Changes in activity were well established by the end of the fixation saccade. The neuronal response was sustained if fixation was sustained. Moreover, the neuronal response began to decrease before the onset of the saccade which broke fixation even though the receptive field location of the target had not yet changed. 4. In these neurones, the discharge rate was not a function of the position of the eye in the orbit. 5. Neurones in which the discharge rate was suppressed during fixation had larger receptive fields than cells in which the discharge rate was enhanced during fixation. There were fewer fixation-suppressed cells (n = 7, 5%) than fixation-activated cells (n = 23, 17%). PMID:2607434

  16. Computer-assisted percutaneous scaphoid fixation: concepts and evolution.

    PubMed

    Smith, Erin J; Ellis, Randy E; Pichora, David R

    2013-11-01

    Background The treatment for undisplaced scaphoid waist fractures has evolved from conventional cast immobilization to percutaneous screw insertion. Percutaneous fixation reduces some of the risks of open surgery, but can be technically demanding and carries the risk of radiation exposure. Recently, computer-assisted percutaneous scaphoid fixation (CAPSF) has been gaining interest. Materials and Methods Conventional percutaneous scaphoid fixation is performed under fluoroscopic guidance and involves insertion of a guide wire along the length of the scaphoid to facilitate placement of a cannulated screw. Adapting computer-assisted techniques for scaphoid fixation poses several unique challenges including patient tracking and registration. Results To date, five groups have successfully implemented systems for CAPSF. These systems have implemented wrist immobilization strategies to resolve the issue of patient tracking and have developed unique guidance techniques incorporating 2D fluoroscope, cone-beam CT, and ultrasound, to circumvent patient-based registration. Conclusions Computer-aided percutaneous pinning of scaphoid waist fractures can significantly reduce radiation exposure and has the potential to improve the accuracy of this procedure. This article reviews the rationale for, and the evolution of, CAPSF and describes the key principles of computer-assisted technology.

  17. Problems and Promises of Assaying the Genetic Potential for Nitrogen Fixation in the Marine Environment

    PubMed

    Zehr; Capone

    1996-11-01

    Nitrogen fixation in the sea has attracted the attention of ecologists for decades. Much is known about the habitats in which it occurs and some of the factors that limit N2 fixation activity in different environments, but we still know little about the organisms that fix nitrogen, and what limits the growth and distribution of these organisms in marine environments. Molecular biology technological developments have provided tools for detecting and characterizing N2-fixing organisms in the environment. These techniques hold great promise for unraveling the mysteries and paradoxes of N2 fixation in the sea. In this review, we address the theoretical basis for the use of a molecular approach to N2 fixation, highlight the strengths and weaknesses of the approach, and provide case studies that demonstrate the potential contribution of molecular biology approaches to studies of N2 fixation in the sea.

  18. Establishment of the 1st World Health Organization International Standard for Plasmodium falciparum DNA for nucleic acid amplification technique (NAT)-based assays

    PubMed Central

    Padley, David J; Heath, Alan B; Sutherland, Colin; Chiodini, Peter L; Baylis, Sally A

    2008-01-01

    Background In order to harmonize results for the detection and quantification of Plasmodium falciparum DNA by nucleic acid amplification technique (NAT)-based assays, a World Health Organization (WHO) collaborative study was performed, evaluating a series of candidate standard preparations. Methods Fourteen laboratories from 10 different countries participated in the collaborative study. Four candidate preparations based upon blood samples parasitaemic for P. falciparum were evaluated in the study. Sample AA was lyophilized, whilst samples BB, CC and DD were liquid/frozen preparations. The candidate standards were tested by each laboratory at a range of dilutions in four independent assays, using both qualitative and quantitative NAT-based assays. The results were collated and analysed statistically. Results Twenty sets of data were returned from the participating laboratories and used to determine the mean P. falciparum DNA content for each sample. The mean log10 "equivalents"/ml were 8.51 for sample AA, 8.45 for sample BB, 8.35 for sample CC, and 5.51 for sample DD. The freeze-dried preparation AA, was examined by accelerated thermal degradation studies and found to be highly stable. Conclusion On the basis of the collaborative study, the freeze-dried material, AA (NIBSC code No. 04/176) was established as the 1st WHO International Standard for P. falciparum DNA NAT-based assays and has been assigned a potency of 109 International Units (IU) per ml. Each vial contains 5 × 108 IU, equivalent to 0.5 ml of material after reconstitution. PMID:18652656

  19. A 4:1 stoichiometric binding and stabilization of mitoxantrone-parallel stranded G-quadruplex complex established by spectroscopy techniques.

    PubMed

    Pradeep, Tarikere Palakashan; Barthwal, Ritu

    2016-09-01

    Small molecule ligands which specifically bind and stabilize G-quadruplex structures in telomeric ends inhibit the activity of telomerase enzyme, an important marker for cancer. Understanding of the binding mode of ligand-G quadruplex complex is important for evaluating relative efficacy of anti-tumor drugs. The present study is focused on interaction of anti-tumor drug mitoxantrone (MTX) with tetra-molecular parallel stranded G-quadruplex sequence d-TTGGGGT using absorbance, fluorescence and circular dichroism spectroscopy techniques. Absorbance of mitoxantrone shows hypochromism up to MTX (D)/DNA quadruplex (N) ratio ~5, followed by hyperchromism up to D/N=0.21 accompanied by a red shift of 15nm. The fluorescence emission of MTX shows decrease up to D/N ~5 and then increases with red shift of 8nm. The two observed fluorescent lifetimes, 0.17ns (91%) and 0.44ns (9%), indicate dual binding mode. Absence of isobestic and isoemissive point indicates presence of multiple complexes. Circular Dichroism spectra showing positive induced band at 645nm and two exciton bands centered at 619 and 664nm suggest binding of mitoxantrone as a dimer. Proton NMR studies show intermolecular MTX-MTX short contacts confirming existence of stacked dimer of MTX. Thermal melting transitions of DNA saturate at D/N=4 with ΔTm=25°C. The results establish highly specific external groove binding of 4 molecules of mitoxantrone as two dimers at two distinct sites of DNA. PMID:27362369

  20. Influence of Target Parameters on Fixation Stability in Normal and Strabismic Monkeys

    PubMed Central

    Pirdankar, Onkar H.; Das, Vallabh E.

    2016-01-01

    Purpose The purpose of this study was to assess the effect of fixation target parameters on fixation instability in strabismic monkeys. Methods One normal and three exotropic monkeys were presented with four differently shaped fixation targets, with three diameters, during monocular or binocular viewing. Fixation targets were white on a black background or vice versa. Binocular eye movements were recorded using the magnetic search coil technique and fixation stability quantified by calculating the bivariate contour ellipse area (BCEA). Results Fixation instability was greater in all the strabismic monkeys compared with the normal monkey. During monocular viewing, strabismic monkeys showed significantly greater instability in the covered eye compared to the fixating eye. Multifactorial ANOVA suggested statistically significant target parameter influences, although effect sizes were small. Thus, a disk-shaped target resulted in greater instability than other target shapes in the viewing eyes of the normal monkey and two of three strabismic monkeys. A similar target-shape effect was also observed in the covered eye. Least instability was elicited with a 0.5° target in the normal monkey and a 1.0° target in the strabismic monkeys, both in the viewing and the covered eye. Target/background polarity effects were idiosyncratic. In strabismic monkeys, stability of the fixating eye during binocular viewing was not different from the stability of the same eye during monocular viewing. Conclusions Abnormal drifts and nystagmus contribute to increased fixation instability in strabismic monkeys. Target parameters (shape and size) that influence fixation stability in a normal animal also affected fixation stability in our sample of strabismic monkeys. PMID:26968739

  1. Prevention of Thumb Web Space Contracture With Multiplanar External Fixation.

    PubMed

    Harper, Carl M; Iorio, Matthew L

    2016-09-01

    Thumb web space contracture following hand trauma can be disabling with numerous reconstructive procedures existing to correct the resultant deformity. Following marked soft tissue injury to the hand we utilized the Stryker Hoffmann II Micro External Fixator System to link the first and second metacarpals by a multiplanar system using 1.6 or 2.0 mm self-drilling half-pins and 3 mm carbon fiber connecting rods. This facilitated placement of the thumb in maximal palmar abduction as well as allowed adjustment of thumb position throughout the postoperative period. This technique was performed on 5 patients. Two patients were treated with a first web space external fixator for table saw injuries to the radial aspect of the hand. An additional 2 patients were treated with a first web space external fixator following metacarpophalangeal joint capsular release in the setting of thermal burns. A fifth patient underwent second ray amputation, trapeziectomy and trapezoidectomy for squamous cell carcinoma with subsequent stabilization with the external fixator. The external fixator was left in place until soft tissues were healed (average 5.5 wk). The patients were allowed to mobilize their hand in as much as the external fixator allowed, and no device-associated complications were noted. Thumb web space was preserved with passive and supple thumb circumduction and web space abduction/adduction in all patients at an average follow-up of 5 months. The average Quick Dash Score was 35±5 and the average Modern Activity Subjective Survey of 2007 was 30±8.

  2. Prevention of Thumb Web Space Contracture With Multiplanar External Fixation.

    PubMed

    Harper, Carl M; Iorio, Matthew L

    2016-09-01

    Thumb web space contracture following hand trauma can be disabling with numerous reconstructive procedures existing to correct the resultant deformity. Following marked soft tissue injury to the hand we utilized the Stryker Hoffmann II Micro External Fixator System to link the first and second metacarpals by a multiplanar system using 1.6 or 2.0 mm self-drilling half-pins and 3 mm carbon fiber connecting rods. This facilitated placement of the thumb in maximal palmar abduction as well as allowed adjustment of thumb position throughout the postoperative period. This technique was performed on 5 patients. Two patients were treated with a first web space external fixator for table saw injuries to the radial aspect of the hand. An additional 2 patients were treated with a first web space external fixator following metacarpophalangeal joint capsular release in the setting of thermal burns. A fifth patient underwent second ray amputation, trapeziectomy and trapezoidectomy for squamous cell carcinoma with subsequent stabilization with the external fixator. The external fixator was left in place until soft tissues were healed (average 5.5 wk). The patients were allowed to mobilize their hand in as much as the external fixator allowed, and no device-associated complications were noted. Thumb web space was preserved with passive and supple thumb circumduction and web space abduction/adduction in all patients at an average follow-up of 5 months. The average Quick Dash Score was 35±5 and the average Modern Activity Subjective Survey of 2007 was 30±8. PMID:27203276

  3. Biomechanical analysis on transverse tibial fixation in anterior cruciate ligament reconstructions☆

    PubMed Central

    Filho, Edmar Stieven; Mendes, Mariane Henseler Damaceno; Claudino, Stephanie; Baracho, Filipe; Borges, Paulo César; da Cunha, Luiz Antonio Munhoz

    2015-01-01

    Objective To verify whether the combination of tibial cross pin fixation and femoral screw fixation presents biomechanical advantages when compared to femoral cross pin fixation and tibial screw fixation for the reconstruction of the anterior cruciate ligament (ACL). Methods Thirty-eight porcine knees and bovine extensor digitorum tendons were used as the graft materials. The tests were performed in three groups: (1) standard, used fourteen knees, and the grafts were fixated with the combination of femoral cross pin and a tibial screw; (2) inverted, used fourteen knees with an inverted combination of tibial cross pin and a femoral screw; (3) control, ten control tests performed with intact ACL. After the grafts fixation, all the knees were subjected to tensile testing to determine yield strength and ultimate strength. Results There was no statistically significant difference in survival techniques in regard to strength, yield load and tension. There was a higher survival compared in the standard curves of yield stress (p < 0.05). Conclusion There is no biomechanical advantage, observed in animal models testing, in the combination of tibial cross pin fixation and femoral screw when compared to femoral cross pin fixation and tibial screw. PMID:26229913

  4. 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

  5. Fixation method does not affect restoration of rotation center in hip replacements: A single-site retrospective study

    PubMed Central

    2012-01-01

    Background Aseptic loosening is one of the greatest problems in hip replacement surgery. The rotation center of the hip is believed to influence the longevity of fixation. The aim of this study was to compare the influence of cemented and cementless cup fixation techniques on the position of the center of rotation because cemented cup fixation requires the removal of more bone for solid fixation than the cementless technique. Methods We retrospectively compared pre- and post-operative positions of the hip rotation center in 25 and 68 patients who underwent artificial hip replacements in our department in 2007 using cemented or cementless cup fixation, respectively, with digital radiographic image analysis. Results The mean horizontal and vertical distances between the rotation center and the acetabular teardrop were compared in radiographic images taken pre- and post-operatively. The mean horizontal difference was −2.63 mm (range: -11.00 mm to 10.46 mm, standard deviation 4.23 mm) for patients who underwent cementless fixation, and −2.84 mm (range: -10.87 to 5.30 mm, standard deviation 4.59 mm) for patients who underwent cemented fixation. The mean vertical difference was 0.60 mm (range: -20.15 mm to 10.00 mm, standard deviation 3.93 mm) and 0.41 mm (range: -9.26 mm to 6.54 mm, standard deviation 3.58 mm) for the cementless and cemented fixation groups, respectively. The two fixation techniques had no significant difference on the position of the hip rotation center in the 93 patients in this study. Conclusions The hip rotation center was similarly restored using either the cemented or cementless fixation techniques in this patient cohort, indicating that the fixation technique itself does not interfere with the position of the center of rotation. To completely answer this question further studies with more patients are needed. PMID:22686355

  6. 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

  7. 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

  8. STIFF ELBOW TREATMENT BY INTERPOSING ARTHROPLASTY ASSOCIATED TO HINGED EXTERNAL FIXATOR

    PubMed Central

    Miyazaki, Alberto Naoki; Fregoneze, Marcelo; Santos, Pedro Doneux; Silva, Luciana Andrade da; Junior, Nelson Gennaro; Checchia, Sergio Luiz

    2015-01-01

    Objective: Assess the results of the elbow/fascia lata interposing arthroplasty technique associated to the use of a hinged external fixator in the treatment of stiff elbow. Methods: Between 2001 and 2006, five cases of stiff elbow were operated and followed up by the Shoulder and Elbow Group of the Santa Casa Misericórdia de São Paulo Medical Sciences School, establishing the following as inclusion criteria: patients with below-functional elbow range of motion associated to degeneration on that joint, for whom total prosthesis had not been indicated. Patients' ages ranged from 21 to 55 years (mean: 38). Male gender was prevalent (four cases), and, in all cases, the dominant side was operated. Concerning etiology, two cases of infectious arthritis sequels, one post-trauma sequel, and two rheumatoid arthritis were found. Preoperative range of motion ranged from 20° to 30° of flexion-extension; in two cases, fixed contracture existed in flexion at 30° and 65°. The patients were assessed according to Bruce-modified AMA criteria. Results: The mean follow up time was 54 months. All patients showed improvement of the Bruce index, which, preoperatively, was 43.5, increasing to 88.2 postoperatively. We found two excellent cases, one good, one fair, and one poor. Conclusion: Fascia lata interposing arthroplasty associated to the use of a dynamic external fixator on stiff elbows is a feasible alternative for patients not indicated to total elbow arthroplasty. PMID:27022516

  9. Awake craniotomy using electromagnetic navigation technology without rigid pin fixation.

    PubMed

    Morsy, Ahmed A; Ng, Wai Hoe

    2015-11-01

    We report our institutional experience using an electromagnetic navigation system, without rigid head fixation, for awake craniotomy patients. The StealthStation® S7 AxiEM™ navigation system (Medtronic, Inc.) was used for this technique. Detailed preoperative clinical and neuropsychological evaluations, patient education and contrast-enhanced MRI (thickness 1.5mm) were performed for each patient. The AxiEM Mobile Emitter was typically placed in a holder, which was mounted to the operating room table, and a non-invasive patient tracker was used as the patient reference device. A monitored conscious sedation technique was used in all awake craniotomy patients, and the AxiEM Navigation Pointer was used for navigation during the procedure. This offers the same accuracy as optical navigation, but without head pin fixation or interference with intraoperative neurophysiological techniques and surgical instruments. The application of the electromagnetic neuronavigation technology without rigid head fixation during an awake craniotomy is accurate, and offers superior patient comfort. It is recommended as an effective adjunctive technique for the conduct of awake surgery.

  10. Awake craniotomy using electromagnetic navigation technology without rigid pin fixation.

    PubMed

    Morsy, Ahmed A; Ng, Wai Hoe

    2015-11-01

    We report our institutional experience using an electromagnetic navigation system, without rigid head fixation, for awake craniotomy patients. The StealthStation® S7 AxiEM™ navigation system (Medtronic, Inc.) was used for this technique. Detailed preoperative clinical and neuropsychological evaluations, patient education and contrast-enhanced MRI (thickness 1.5mm) were performed for each patient. The AxiEM Mobile Emitter was typically placed in a holder, which was mounted to the operating room table, and a non-invasive patient tracker was used as the patient reference device. A monitored conscious sedation technique was used in all awake craniotomy patients, and the AxiEM Navigation Pointer was used for navigation during the procedure. This offers the same accuracy as optical navigation, but without head pin fixation or interference with intraoperative neurophysiological techniques and surgical instruments. The application of the electromagnetic neuronavigation technology without rigid head fixation during an awake craniotomy is accurate, and offers superior patient comfort. It is recommended as an effective adjunctive technique for the conduct of awake surgery. PMID:26249245

  11. Passive archwires for intermaxillary fixation in surgical cases: a clinical report.

    PubMed

    Alessandri Bonetti, Giulio; Incerti Parenti, Serena; Gracco, Antonio

    2011-01-01

    In intraoperative intermaxillary fixation (IMF), bonding a minimally adapted, rectangular, stainless steel, preformed archwire directly to the teeth with a light-cured composite resin can offer many benefits to clinicians and patients. The procedure is easier and less time-consuming than conventional bracket placement, the risk of occlusal interference is reduced and the patient's comfort is increased. With the use of composite resin, the wire fits buccal tooth surfaces accurately, thus creating a completely passive anchor unit. Crimpable hooks can be easily adjusted along the archwire, thus establishing different directions of postoperative elastic traction. Furthermore, this technique eliminates soft tissue injuries and tooth root damage, which are risks associated with the use of miniscrews for IMF. In this clinical report, we describe the case of a 50-year-old man, who required a passive anchor unit to assist IMF before undergoing maxillomandibular advancement to treat severe obstructive sleep apnea syndrome.

  12. Functional Nanoscale Imaging of Synaptic Vesicle Cycling with Superfast Fixation.

    PubMed

    Schikorski, Thomas

    2016-01-01

    Functional imaging is the measurement of structural changes during an ongoing physiological process over time. In many cases, functional imaging has been implemented by tracking a fluorescent signal in live imaging sessions. Electron microscopy, however, excludes live imaging which has hampered functional imaging approaches on the ultrastructural level. This barrier was broken with the introduction of superfast fixation. Superfast fixation is capable of stopping and fixing membrane traffic at sufficient speed to capture a physiological process at a distinct functional state. Applying superfast fixation at sequential time points allows tracking of membrane traffic in a step-by-step fashion.This technique has been applied to track labeled endocytic vesicles at central synapses as they pass through the synaptic vesicle cycle. At synapses, neurotransmitter is released from synaptic vesicles (SVs) via fast activity-dependent exocytosis. Exocytosis is coupled to fast endocytosis that retrieves SVs components from the plasma membrane shortly after release. Fluorescent FM dyes that bind to the outer leaflet of the plasma membrane enter the endocytic vesicle during membrane retrieval and remain trapped in endocytic vesicles have been widely used to study SV exo-endocytic cycling in live imaging sessions. FM dyes can also be photoconverted into an electron-dense diaminobenzidine polymer which allows the investigation of SV cycling in the electron microscope. The combination of FM labeling with superfast fixation made it possible to track the fine structure of endocytic vesicles at 1 s intervals. Because this combination is not specialized to SV cycling, many other cellular processes can be studied. Furthermore, the technique is easy to set up and cost effective.This chapter describes activity-dependent FM dye labeling of SVs in cultured hippocampal neurons, superfast microwave-assisted fixation, photoconversion of the fluorescent endocytic vesicles, and the analysis of

  13. Complement-Fixation Analysis of Four Subtypes of Foot-and-Mouth Disease Virus Type A

    PubMed Central

    Lobo, C. A.; Cowan, K. M.; Hanson, R. P.

    1973-01-01

    Complement-fixation patterns were established for four subtypes of foot-and-mouth disease virus by block assays against homologous and heterologous antiserum. Inhibition of fixation by excess antigen was observed in most homologous systems but rarely in the heterologous systems. The heterologous antibody titers were, in all instances, considerably lower than those for the homologous systems. Although relatively high dilutions of antiserum may be desirable for subtyping, higher concentrations of antibody should be used for determining serological types. PMID:4356470

  14. Robot-assisted Anterior Odontoid Screw Fixation: A Case Report.

    PubMed

    Tian, Wei; Wang, Han; Liu, Ya-Jun

    2016-08-01

    Anterior odontoid screw fixation has been proved to be effective but technically challenging because the difficult approach is associated with high risks of screw malposition and damage to surrounding vital structures. Navigation techniques are therefore increasingly being used to improve safety and accuracy. However, no robot-assisted odontoid screw fixation has yet been reported. We here report a 61-year-old woman with a type II dens fracture on whom anterior odontoid screw fixation was performed under the guidance of a newly developed robotic system (TiRobot, co-designed by Beijing Jishuitan Hospital and TINAVI Medical Technologies). One odontoid screw was safely and accurately placed, the calculated deviation between the planned and actual positions being 0.9 mm. No intraoperative complications were identified and the patient was discharged on Day 5. Follow-up studies after 2 weeks showed good clinical and radiological results. We believe this is the first reported case of robot-assisted anterior odontoid screw fixation. We consider that complicated procedures can become feasible, safe and accurate using TiRobot systems.

  15. Robot-assisted Anterior Odontoid Screw Fixation: A Case Report.

    PubMed

    Tian, Wei; Wang, Han; Liu, Ya-Jun

    2016-08-01

    Anterior odontoid screw fixation has been proved to be effective but technically challenging because the difficult approach is associated with high risks of screw malposition and damage to surrounding vital structures. Navigation techniques are therefore increasingly being used to improve safety and accuracy. However, no robot-assisted odontoid screw fixation has yet been reported. We here report a 61-year-old woman with a type II dens fracture on whom anterior odontoid screw fixation was performed under the guidance of a newly developed robotic system (TiRobot, co-designed by Beijing Jishuitan Hospital and TINAVI Medical Technologies). One odontoid screw was safely and accurately placed, the calculated deviation between the planned and actual positions being 0.9 mm. No intraoperative complications were identified and the patient was discharged on Day 5. Follow-up studies after 2 weeks showed good clinical and radiological results. We believe this is the first reported case of robot-assisted anterior odontoid screw fixation. We consider that complicated procedures can become feasible, safe and accurate using TiRobot systems. PMID:27627725

  16. A mini external fixator for hand and finger fractures constructed from readily available materials.

    PubMed

    Walter, Frank L; Papandrea, Rick F

    2011-12-01

    Phalangeal and metacarpal fractures with severe comminution and/or soft tissue compromise can present a challenge for the orthopedic surgeon. Maintaining viability of the soft tissues while providing rigid fixation of bony injuries is the goal when treating these injuries. Commercially available mini external fixators can help to achieve these goals. However, these devices are costly and are not always available when the surgeon needs them. In this technique study, we discuss the implementation of a mini external fixator using readily available implements in the operating room that is efficient, cost effective, and easy to apply.

  17. 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.

  18. Modeling fixation locations using spatial point processes.

    PubMed

    Barthelmé, Simon; Trukenbrod, Hans; Engbert, Ralf; Wichmann, Felix

    2013-10-01

    Whenever eye movements are measured, a central part of the analysis has to do with where subjects fixate and why they fixated where they fixated. To a first approximation, a set of fixations can be viewed as a set of points in space; this implies that fixations are spatial data and that the analysis of fixation locations can be beneficially thought of as a spatial statistics problem. We argue that thinking of fixation locations as arising from point processes is a very fruitful framework for eye-movement data, helping turn qualitative questions into quantitative ones. We provide a tutorial introduction to some of the main ideas of the field of spatial statistics, focusing especially on spatial Poisson processes. We show how point processes help relate image properties to fixation locations. In particular we show how point processes naturally express the idea that image features' predictability for fixations may vary from one image to another. We review other methods of analysis used in the literature, show how they relate to point process theory, and argue that thinking in terms of point processes substantially extends the range of analyses that can be performed and clarify their interpretation.

  19. 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.

  20. 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.

  1. Effect of pin location on stability of pelvic external fixation.

    PubMed

    Kim, W Y; Hearn, T C; Seleem, O; Mahalingam, E; Stephen, D; Tile, M

    1999-04-01

    Pelvic external fixators allow two locations of pin purchase: anterosuperior (into the iliac crest) and anteroinferior (into the supraacetabular dense bone, between the anterior superior and anterior inferior iliac spine). The purpose of this study was to compare the stability of these two methods of fixation on Tile Type B1 (open book) and C (unstable) pelvic injuries. Five unembalmed cadaveric pelves (mean age, 68 years; four males and one female) were loaded vertically in a servohydraulic testing machine in a standing posture. The AO tubular system and Orthofix were used. On each pelvis, a Type B1 injury was simulated. Each external fixator was applied in each location in random order. Cyclic loads were applied through the sacral body to a maximum of approximately 200 N while force and displacement of the pelvic ring were recorded digitally. Sacroiliac joint motion was quantified tridimensionally with displacement transducers, mounted on the sacrum and contacting a target fixed to the posterior superior iliac spine. A Type C injury was created and augmented with two iliosacral lag screws, and the tests were repeated. For the Type B1 injuries with anteroinferior pin purchase, the mean stiffness was 201.2 N/mm for the AO frame and 203.2 N/mm for the Orthofix. For the anterosuperior frames the mean stiffness was 143.9 N/mm for the AO frame and 163.3 N/mm for the Orthofix. For Type B1 and Type C injuries, the anteroinferior location of pin purchase resulted in significantly reduced sacroiliac joint separation. There were no significant differences between the frame types. Dissection of the preinserted anatomic specimen revealed no evidence of injury to the lateral femoral cutaneous nerve after blunt dissection and drilling with protective drill sleeves. It is concluded that the anteroinferior location of external fixation pins is a safe technique with the potential for increased stability of fixation.

  2. The course of bone healing is influenced by the initial shear fixation stability.

    PubMed

    Schell, H; Epari, D R; Kassi, J P; Bragulla, H; Bail, H J; Duda, G N

    2005-09-01

    Fracture healing is influenced by fixation stability and experimental evidence suggests that the initial mechanical conditions may determine the healing outcome. We hypothesised that mechanical conditions influence not only the healing outcome, but also the early phase of fracture healing. Additionally, it was hypothesised that decreased fixation stability characterised by an increased shear interfragmentary movement results in a delay in healing. Sixty-four sheep underwent a mid-shaft tibial osteotomy which was treated with either a rigid or a semi-rigid external fixator. Animals were sacrificed at 2, 3, 6 and 9 weeks postoperatively and the fracture callus was analysed using radiological, biomechanical and histological techniques. The tibia treated with semi-rigid fixation showed inferior callus stiffness and quality after 6 weeks. At 9 weeks, the calluses were no longer distinguishable in their mechanical competence. The calluses at 9 weeks produced under rigid fixation were smaller and consisted of a reduced fibrous tissue component. These results demonstrate that the callus formation over the course of healing differed both morphologically and in the rate of development. In this study, we provide evidence that the course of healing is influenced by the initial fixation stability. The semi-rigid fixator did not result in delayed healing, but a less optimal healing path was taken. An upper limit of stability required for successful healing remains unknown, however a limit by which healing is less optimal has been determined.

  3. Tibial press-fit fixation of the hamstring tendons for ACL-reconstruction.

    PubMed

    Jagodzinski, M; Scheunemann, K; Knobloch, K; Albrecht, K; Krettek, C; Hurschler, C; Zeichen, J

    2006-12-01

    Press-fit fixation of patellar tendon bone anterior cruciate ligament autografts is an interesting technique because no hardware is necessary to achieve fixation. Up till the present point, there is no biomechanical data available for the tibial press-fit fixation of the hamstring tendons. Hamstring tendons of 21 human cadavers (age: 41.9 +/- 13.1 years) were used. A press-fit fixation with looped semitendinosus and gracilis tendons secured by a tape (T) over a bone bridge, or by a baseball-stitched suture (S), was compared with degradable interference screw fixation (I) in 21 porcine tibiae. The constructs were cyclically strained and subsequently loaded to failure. The maximum load to failure, stiffness, and elongation during cyclical loading were measured. The maximum load to failure was highest for the T-fixation at 970 +/- 83 N, followed by the I-fixation with 544 +/- 109 N, and the S-fixation with 402 +/- 78 N (P < 0.03). Stiffness of the constructs averaged 78 +/- 13 N/mm for T, 108 +/- 18 N/mm for S, and 162 +/- 27 N/mm for I (P < 0.03). Elongation during initial cyclical loading was 2.0 +/- 0.6 mm for T, 3.3 +/- 1.1 mm for S, and 1.4 +/- 0.5 mm for I (S inferior to I and T, P<0.05). Elongation between the 20th and 1,500th loading cycle was lower for T (2.2 +/- 0.7 mm) compared with I (4.1 +/- 2.7 mm) and S (4.8 +/- 0.7 mm; P < 0.001). The T-fixation technique exhibited a significantly higher failure load than the S-, and I- techniques. All techniques exhibited larger elongation during initial cyclical loading than is reported in the literature for grafts with bone blocks. Only one technique (T) showed satisfactory elongation behavior during long-term cyclic loading. Interference screw fixation demonstrated significantly higher stiffness. Only one of the investigated techniques (T) seemed to exhibit adequate mechanical properties necessary for early aggressive rehabilitation programs.

  4. 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...

  5. 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...

  6. 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...

  7. 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

  8. Microsaccades counteract visual fading during fixation.

    PubMed

    Martinez-Conde, Susana; Macknik, Stephen L; Troncoso, Xoana G; Dyar, Thomas A

    2006-01-19

    Our eyes move continually, even while we fixate our gaze on an object. If fixational eye movements are counteracted, our perception of stationary objects fades completely, due to neural adaptation. Some studies have suggested that fixational microsaccades refresh retinal images, thereby preventing adaptation and fading. However, other studies disagree, and so the role of microsaccades remains unclear. Here, we correlate visibility during fixation to the occurrence of microsaccades. We asked subjects to indicate when Troxler fading of a peripheral target occurs, while simultaneously recording their eye movements with high precision. We found that before a fading period, the probability, rate, and magnitude of microsaccades decreased. Before transitions toward visibility, the probability, rate, and magnitude of microsaccades increased. These results reveal a direct link between suppression of microsaccades and fading and suggest a causal relationship between microsaccade production and target visibility during fixation.

  9. Staged Columnar Fixation of Bicondylar Tibial Plateaus: A Cheaper Alternative to External Fixation.

    PubMed

    Perdue, Aaron; Greenberg, Sarah E; Sathiyakumar, Vasanth; Thakore, Rachel V; Mir, Hassan R; Obremskey, William T; Sethi, Manish K

    2016-01-01

    The objective of this study was to compare complication rates and costs of staged columnar fixation (SCF) to external fixation for bicondylar tibial plateau fractures. Patients who received SCF or temporary external fixation across a 3-year period at a major level I trauma center underwent a retrospective chart review for associated complications. Fisher's exact analysis was used to determine any statistical difference in complication rates between both groups. However, there was no significant difference in complication rates between the SCF and external fixator groups. Average medial plate costs for SCF were $2131 compared with an average external fixator cost of $4070 (p < .0001). Given that all patients with external fixation undergo eventual medial and lateral plating, savings with SCF include $4070 plus operative costs for removing the fixator. As our health care system focuses on cost-cutting efforts, orthopaedic trauma surgeons must explore cheaper and equally effective treatment alternatives. PMID:27082883

  10. Imaging infrared spectroscopy for fixation-free liver tumor detection

    NASA Astrophysics Data System (ADS)

    Coe, James V.; Chen, Zhaomin; Li, Ran; Butke, Ryan; Miller, Barrie; Hitchcock, Charles L.; Allen, Heather C.; Povoski, Stephen P.; Martin, Edward W.

    2014-03-01

    Infrared (IR) imaging spectroscopy of human liver tissue slices has been used to identify and characterize a liver metastasis of breast origin (mucinous carcinoma) which was surgically removed from a consenting patient and frozen without formalin fixation or dehydration procedures, so that lipids and water remain in the tissues. Previously, a set of IR metrics was determined for tumors in fixation-free liver tissues facilitating a k-means cluster analysis differentiating tumor from nontumor. Different and more in depth aspects of these results are examined in this work including three metric color imaging, differencing for lipid identification, and a new technique to simultaneously fit band lineshapes and their 2nd derivatives in order to better characterize protein changes.

  11. 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.

  12. Arthroscopic 4-Point Suture Fixation of Anterior Cruciate Ligament Tibial Avulsion Fractures

    PubMed Central

    Boutsiadis, Achilleas; Karataglis, Dimitrios; Agathangelidis, Filon; Ditsios, Konstantinos; Papadopoulos, Pericles

    2014-01-01

    Tibial eminence avulsion fractures are rare injuries occurring mainly in adolescents and young adults. When necessary, regardless of patient age, anatomic reduction and stable internal fixation are mandatory for fracture healing and accurate restoration of normal knee biomechanics. Various arthroscopically assisted fixation methods with sutures, anchors, wires, or screws have been described but can be technically demanding, thus elongating operative times. The purpose of this article is to present a technical variation of arthroscopic suture fixation of anterior cruciate ligament avulsion fractures. Using thoracic drain needles over 2.4-mm anterior cruciate ligament tibial guidewires, we recommend the safe and easy creation of four 2.9-mm tibial tunnels at different angles and at specific points. This technique uses thoracic drain needles as suture passage cannulas and offers 4-point fixation stability, avoiding potential complications of bony bridge fracture and tunnel connection. PMID:25685674

  13. Management of extra-articular fractures of the distal tibia: intramedullary nailing versus plate fixation.

    PubMed

    Casstevens, Chris; Le, Toan; Archdeacon, Michael T; Wyrick, John D

    2012-11-01

    Intramedullary nailing and plate fixation represent two viable approaches to internal fixation of extra-articular fractures of the distal tibia. Although both techniques have demonstrated success in maintaining reduction and promoting stable union, they possess distinct advantages and disadvantages that require careful consideration during surgical planning. Differences in soft-tissue health and construct stability must be considered when choosing between intramedullary nailing and plating of the distal tibia. Recent advances in intramedullary nail design and plate-and-screw fixation systems have further increased the options for management of these fractures. Current evidence supports careful consideration of the risk of soft-tissue complications, residual knee pain, and fracture malalignment in the context of patient and injury characteristics in the selection of the optimal method of fixation.

  14. Comparison of palmar fixed-angle plate fixation with K-wire fixation of distal radius fractures (AO A2, A3, C1) in elderly patients.

    PubMed

    Goehre, F; Otto, W; Schwan, S; Mendel, T; Vergroesen, P P; Lindemann-Sperfeld, L

    2014-03-01

    The objective of this prospective, randomized, controlled trial was to compare the results of two operative techniques used for the treatment of unstable distal radius fractures in elderly patients classified as AO types A2, A3, and C1. Patients were treated with either fixed-angle volar plates or K-wires using a combined Kapandji and Willenegger technique. The functional results were determined after 3, 6, and 12 months. We included 40 patients aged over 65 years. Twenty-one patients were treated with plate fixation and 19 with K-wire fixation. The functional results, after 1 year, were nearly the same in both treatment groups, suggesting that either method is suitable for the treatment of unstable distal radius fractures of AO types A2, A3, and C1 in elderly patients. Sixteen of 21 patients with plate fixation and 17 of 19 patients with K-wire fixation present good results as assessed by the Castaing score. The median DASH score was three in both groups after 1 year. The patients with plate fixation were able to resume activities of daily living 4 weeks earlier. The most common complication was an intermediate post-traumatic median nerve irritation. Both methods are suitable for the treatment of elderly patients with unstable distal radius fractures of AO types A2, A3, and C1. If early functional post-operative care is important, palmar fixed-angle plate fixation is an ideal treatment approach. Otherwise, K-wire fixation is an effective, minimally invasive method with comparable clinical results.

  15. 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

  16. The challenging image-guided abdominal mass biopsy: established and emerging techniques 'if you can see it, you can biopsy it'.

    PubMed

    Sainani, Nisha I; Arellano, Ronald S; Shyn, Paul B; Gervais, Debra A; Mueller, Peter R; Silverman, Stuart G

    2013-08-01

    Image-guided percutaneous biopsy of abdominal masses is among the most commonly performed procedures in interventional radiology. While most abdominal masses are readily amenable to percutaneous biopsy, some may be technically challenging for a number of reasons. Low lesion conspicuity, small size, overlying or intervening structures, motion, such as that due to respiration, are some of the factors that can influence the ability and ultimately the success of an abdominal biopsy. Various techniques or technologies, such as choice of imaging modality, use of intravenous contrast and anatomic landmarks, patient positioning, organ displacement or trans-organ approach, angling CT gantry, triangulation method, real-time guidance with CT fluoroscopy or ultrasound, sedation or breath-hold, pre-procedural image fusion, electromagnetic tracking, and others, when used singularly or in combination, can overcome these challenges to facilitate needle placement in abdominal masses that otherwise would be considered not amenable to percutaneous biopsy. Familiarity and awareness of these techniques allows the interventional radiologist to expand the use of percutaneous biopsy in clinical practice, and help choose the most appropriate technique for a particular patient.

  17. 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

  18. Dinitrogen fixation in aphotic oxygenated marine environments

    PubMed Central

    Rahav, Eyal; Bar-Zeev, Edo; Ohayon, Sarah; Elifantz, Hila; Belkin, Natalia; Herut, Barak; Mulholland, Margaret R.; Berman-Frank, Ilana

    2013-01-01

    We measured N2 fixation rates from oceanic zones that have traditionally been ignored as sources of biological N2 fixation; the aphotic, fully oxygenated, nitrate (NO−3)-rich, waters of the oligotrophic Levantine Basin (LB) and the Gulf of Aqaba (GA). N2 fixation rates measured from pelagic aphotic waters to depths up to 720 m, during the mixed and stratified periods, ranged from 0.01 nmol N L−1 d−1 to 0.38 nmol N L−1 d−1. N2 fixation rates correlated significantly with bacterial productivity and heterotrophic diazotrophs were identified from aphotic as well as photic depths. Dissolved free amino acid amendments to whole water from the GA enhanced bacterial productivity by 2–3.5 fold and N2 fixation rates by ~2-fold in samples collected from aphotic depths while in amendments to water from photic depths bacterial productivity increased 2–6 fold while N2 fixation rates increased by a factor of 2 to 4 illustrating that both BP and heterotrophic N2 fixation were carbon limited. Experimental manipulations of aphotic waters from the LB demonstrated a significant positive correlation between transparent exopolymeric particle (TEP) concentrations and N2 fixation rates. This suggests that sinking organic material and high carbon (C): nitrogen (N) micro-environments (such as TEP-based aggregates or marine snow) could support high heterotrophic N2 fixation rates in oxygenated surface waters and in the aphotic zones. Indeed, our calculations show that aphotic N2 fixation accounted for 37 to 75% of the total daily integrated N2 fixation rates at both locations in the Mediterranean and Red Seas with rates equal or greater to those measured from the photic layers. Moreover, our results indicate that that while N2 fixation may be limited in the surface waters, aphotic, pelagic N2 fixation may contribute significantly to new N inputs in other oligotrophic basins, yet it is currently not included in regional or global N budgets. PMID:23986748

  19. Combining of small fragment screws and large fragment plates for open reduction and internal fixation of periprosthetic humeral fractures.

    PubMed

    Seybold, Dominik; Citak, Mustafa; Königshausen, Matthias; Gessmann, Jan; Schildhauer, Thomas A

    2011-10-01

    Operative treatment of periprosthetic humeral fractures in elderly patients with osteoporotic bone requires a stable fixations technique. The combination of 3.5 cortical screws with washers in a 4.5 Arbeitsgemeinschaft für Osteosynthesefragen, Limited-contact dynamic compression plate or Locking plate, allows a stable periprosthetic fixation with the small 3.5 screws and 4.5 screws above and below the prosthesis, respectively. This combination is a cost-effective technique to treat periprosthetic humeral fractures.

  20. All-Suture Transosseous Repair for Rotator Cuff Tear Fixation Using Medial Calcar Fixation

    PubMed Central

    Aramberri-Gutiérrez, Mikel; Martínez-Menduiña, Amaia; Valencia-Mora, María; Boyle, Simon

    2015-01-01

    We describe an all-suture transosseous repair technique used in the management of rotator cuff tears by means of an all-suture anchor secured on the intra-articular side of the humeral calcar. The technique uses an anterior cruciate ligament guide to ensure accurate positioning of the tunnels, avoiding the articular cartilage and minimizing risk to the neurovascular structures. The distal end of the guide is inserted through a rotator interval portal and passed down to the axillary pouch. The proximal end of the guide is approximated to the greater tuberosity at the cuff footprint, and a complete transosseous tunnel is created with a 2.4-mm drill. An all-suture implant is inserted through this tunnel down to the calcar, and its deployment is visualized under arthroscopy. Gentle traction is applied to the anchor, resulting in a 4-mm concertina of the suture anchor that rests opposed to the medial cortex. The major advantage of this technique is the fixation strength gained from the biomechanically superior cortical bone of the calcar. Furthermore, this method permits greater preservation of bone surface area at the level of the footprint for a larger tendon-to-bone healing surface. This technique also provides an excellent alternative in revision situations. PMID:26052495

  1. Establishing operations

    PubMed Central

    Michael, Jack

    1993-01-01

    The first two books on behavior analysis (Skinner, 1938; Keller & Schoenfeld, 1950) had chapter-length coverage of motivation. The next generation of texts also had chapters on the topic, but by the late 1960s it was no longer being given much treatment in the behavior-analytic literature. The present failure to deal with the topic leaves a gap in our understanding of operant functional relations. A partial solution is to reintroduce the concept of the establishing operation, defined as an environmental event, operation, or stimulus condition that affects an organism by momentarily altering (a) the reinforcing effectiveness of other events and (b) the frequency of occurrence of that part of the organism's repertoire relevant to those events as consequences. Discriminative and motivative variables can be distinguished as follows: The former are related to the differential availability of an effective form of reinforcement given a particular type of behavior; the latter are related to the differential reinforcing effectiveness of environmental events. An important distinction can also be made between unconditioned establishing operations (UEOs), such as food deprivation and painful stimulation, and conditioned establishing operations (CEOs) that depend on the learning history of the organism. One type of CEO is a stimulus that has simply been paired with a UEO and as a result may take on some of the motivative properties of that UEO. The warning stimulus in avoidance procedures is another important type of CEO referred to as reflexive because it establishes its own termination as a form of reinforcement and evokes the behavior that has accomplished such termination. Another CEO is closely related to the concept of conditional conditioned reinforcement and is referred to as a transitive CEO, because it establishes some other stimulus as a form of effective reinforcement and evokes the behavior that has produced that other stimulus. The multiple control of human

  2. 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

  3. Immaturity of Visual Fixations in Dyslexic Children.

    PubMed

    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.

  4. 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

  5. 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.

  6. SU-C-BRD-05: Implementation of Incident Learning in the Safety and Quality Management of Radiotherapy: The Primary Experience in a New Established Program with Advanced Techniques

    SciTech Connect

    Yang, R; Wang, J

    2014-06-15

    Purpose: To explore the implementation and effectiveness of incident learning for the safety and quality of radiotherapy in a new established radiotherapy program with advanced technology. Methods: Reference to the consensus recommendations by American Association of Physicist in Medicine, an incident learning system was specifically designed for reporting, investigating, and learning of individual radiotherapy incidents in a new established radiotherapy program, with 4D CBCT, Ultrasound guided radiotherapy, VMAT, gated treatment delivered on two new installed linacs. The incidents occurring in external beam radiotherapy from February, 2012 to January, 2014 were reported. Results: A total of 33 reports were analyzed, including 28 near misses and 5 incidents. Among them, 5 originated in imaging for planning, 25 in planning, 1 in plan transfer, 1 in commissioning and 1 in treatment delivery. Among them, three near misses originated in the safety barrier of the radiotherapy process. In terms of error type, 1 incident was classified as wrong patient, 7 near misses/incidents as wrong site, 6 as wrong laterality, 5 as wrong dose, 7 as wrong prescription, and 7 as suboptimal plan quality. 5 incidents were all classified as grade 1/2 of dosimetric severity, 1 as grade 0, and the other 4 as grade 1 of medical severity. For the causes/contributory factors, negligence, policy not followed, inadequate training, failure to develop an effective plan, and communication contributed to 19, 15, 12, 5 and 3 near misses/incidents, respectively. The average incident rate per 100 patients treated was 0.4; this rate fell to 0.28% in the second year from 0.56% in the first year. The rate of near miss fell to 1.24% from 2.22%. Conclusion: Effective incident learning can reduce the occurrence of near miss/incidents, enhance the culture of safety. Incident learning is an effective proactive method for improving the quality and safety of radiotherapy.

  7. Fixational eye movements in amblyopia and strabismus.

    PubMed

    Ciuffreda, K J; Kenyon, R V; Stark, L

    1979-11-01

    Horizontal eye position was monitored using a photoelectric method during monocular and binocular fixation in four patients having amblyopia without strabismus, thirteen patients having constant strabismus with amblyopia, and five patients having intermittent strabismus. Four abnormalities of fixation were found: increased drift, saccadic intrusions, manifest nystagmus, and latent nystagmus. Increased drift was related to the presence of amblyopia, while saccadic intrusions and nystagmus were related to the presence of strabismus. Understanding dynamic aspects of oculomotor control can provide insight into clinical assessment of fixation in amblyopia and strabismus.

  8. Internal fixation in a combat theater hospital.

    PubMed

    Large, Thomas M; Bonds, Cale; Howard, Michael

    2013-08-01

    Limited data are available on the use of internal fixation in combat zone hospitals. The authors performed a retrospective review of 713 surgical cases during 2 Operation Enduring Freedom deployments to a Level III theater hospital in 2007 and 2009 to 2010. The epidemiology and short- to intermediate-term outcomes of patients treated with internal fixation devices were studied. The authors found that, with judicious use, internal fixation under a damage control protocol in a combat theater hospital can be performed with acceptable complication rates. PMID:23937739

  9. 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

  10. 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.

  11. 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

  12. eSeeTrack--visualizing sequential fixation patterns.

    PubMed

    Tsang, Hoi Ying; Tory, Melanie; Swindells, Colin

    2010-01-01

    We introduce eSeeTrack, an eye-tracking visualization prototype that facilitates exploration and comparison of sequential gaze orderings in a static or a dynamic scene. It extends current eye-tracking data visualizations by extracting patterns of sequential gaze orderings, displaying these patterns in a way that does not depend on the number of fixations on a scene, and enabling users to compare patterns from two or more sets of eye-gaze data. Extracting such patterns was very difficult with previous visualization techniques. eSeeTrack combines a timeline and a tree-structured visual representation to embody three aspects of eye-tracking data that users are interested in: duration, frequency and orderings of fixations. We demonstrate the usefulness of eSeeTrack via two case studies on surgical simulation and retail store chain data. We found that eSeeTrack allows ordering of fixations to be rapidly queried, explored and compared. Furthermore, our tool provides an effective and efficient mechanism to determine pattern outliers. This approach can be effective for behavior analysis in a variety of domains that are described at the end of this paper.

  13. Fiber-mutant technique can augment gene transduction efficacy and anti-tumor effects against established murine melanoma by cytokine-gene therapy using adenovirus vectors.

    PubMed

    Okada, Yuka; Okada, Naoki; Nakagawa, Shinsaku; Mizuguchi, Hiroyuki; Kanehira, Makiko; Nishino, Naoko; Takahashi, Koichi; Mizuno, Nobuyasu; Hayakawa, Takao; Mayumi, Tadanori

    2002-03-01

    Melanoma cells are relatively resistant to adenovirus vector (Ad)-mediated gene transfer due to the low expression of Coxsackie-adenovirus receptor (CAR), which acts as a primitive Ad-receptor. Therefore, extremely high doses of Ad are required for effective gene therapy against melanoma. In the present study, we investigated whether fiber-mutant Ad containing the Arg-Gly-Asp (RGD) sequence in the fiber knob could promote gene delivery and anti-tumor effects in the murine B16 BL6 tumor model. B16 BL6 cells (in vitro) and tumors (in vivo) infected with RGD fiber-mutant Ad containing a tumor necrosis factor alpha gene (Ad-RGD-TNFalpha) produced more TNFalpha than those infected with conventional Ad-TNFalpha. In addition, Ad-RGD-TNFalpha required about one-tenth the dosage of Ad-TNFalpha for induction of equal therapeutic effects upon intratumoral injection into established B16 BL6 tumors. Furthermore, the combination of both TNFalpha- and interleukin 12-expressing RGD fiber-mutant Ads exhibited more effective tumor regression than the Ad expressing each alone. These results suggested that the fiber-mutant for altering Ad-tropism is a very potent technology for advancing gene therapy for melanoma. PMID:11809531

  14. Local bleaching thresholds established by remote sensing techniques vary among reefs with deviating bleaching patterns during the 2012 event in the Arabian/Persian Gulf.

    PubMed

    Shuail, Dawood; Wiedenmann, Jörg; D'Angelo, Cecilia; Baird, Andrew H; Pratchett, Morgan S; Riegl, Bernhard; Burt, John A; Petrov, Peter; Amos, Carl

    2016-04-30

    A severe bleaching event affected coral communities off the coast of Abu Dhabi, UAE in August/September, 2012. In Saadiyat and Ras Ghanada reefs ~40% of the corals showed signs of bleaching. In contrast, only 15% of the corals were affected on Delma reef. Bleaching threshold temperatures for these sites were established using remotely sensed sea surface temperature (SST) data recorded by MODIS-Aqua. The calculated threshold temperatures varied between locations (34.48 °C, 34.55 °C, 35.05 °C), resulting in site-specific deviations in the numbers of days during which these thresholds were exceeded. Hence, the less severe bleaching of Delma reef might be explained by the lower relative heat stress experienced by this coral community. However, the dominance of Porites spp. that is associated with the long-term exposure of Delma reef to elevated temperatures, as well as the more pristine setting may have additionally contributed to the higher coral bleaching threshold for this site.

  15. Local bleaching thresholds established by remote sensing techniques vary among reefs with deviating bleaching patterns during the 2012 event in the Arabian/Persian Gulf.

    PubMed

    Shuail, Dawood; Wiedenmann, Jörg; D'Angelo, Cecilia; Baird, Andrew H; Pratchett, Morgan S; Riegl, Bernhard; Burt, John A; Petrov, Peter; Amos, Carl

    2016-04-30

    A severe bleaching event affected coral communities off the coast of Abu Dhabi, UAE in August/September, 2012. In Saadiyat and Ras Ghanada reefs ~40% of the corals showed signs of bleaching. In contrast, only 15% of the corals were affected on Delma reef. Bleaching threshold temperatures for these sites were established using remotely sensed sea surface temperature (SST) data recorded by MODIS-Aqua. The calculated threshold temperatures varied between locations (34.48 °C, 34.55 °C, 35.05 °C), resulting in site-specific deviations in the numbers of days during which these thresholds were exceeded. Hence, the less severe bleaching of Delma reef might be explained by the lower relative heat stress experienced by this coral community. However, the dominance of Porites spp. that is associated with the long-term exposure of Delma reef to elevated temperatures, as well as the more pristine setting may have additionally contributed to the higher coral bleaching threshold for this site. PMID:26971815

  16. 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.

  17. 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

  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. Three-dimensional stabilization provided by the external spinal fixator compared to two internal fixation devices: a biomechanical in vitro flexibility study.

    PubMed

    Lund, Teija; Nydegger, Thomas; Rathonyi, Gabor; Nolte, Lutz-Peter; Schlenzka, Dietrich; Oxland, Thomas R

    2003-10-01

    We performed an in vitro study to investigate the stabilization (i.e. motion reduction) provided by the external spinal fixator (ESF), and to compare the three configurations of the ESF with two internal fixation techniques. Six human cadaveric lumbar spine specimens (L3-S1) were subjected to multidirectional flexibility testing in six configurations: (1) intact, (2) ESF in neutral, (3) ESF in distraction, (4) ESF in compression, (5) translaminar facet screw fixation, and (6) internal transpedicular fixation. Both the ESF and the internal fixation systems stabilized the specimens from L4 to S1. In each testing configuration, pure bending moments of flexion-extension, bilateral axial rotation, and bilateral lateral bending were applied to the uppermost vertebra stepwise to a maximum of 10 Nm. The rigid body motion between the vertebrae was measured using an optoelectronic camera system, and custom software was used to calculate the intervertebral rotations. For each applied motion in all testing configurations, the total range of motion (ROM) of L4-S1 is reported. All three ESF configurations stabilized the spine significantly when compared to the intact specimen. The ESF in compression provided significantly more stabilization in flexion-extension than the two other ESF configurations, but no other significant differences were found between the three ESF modes. In flexion-extension the ESF stabilized the spine significantly when compared with the two internal fixation devices. Only in bilateral lateral bending was the ESF inferior to internal transpedicular fixation in providing stabilization. The results of the present study suggest that the ESF provides a high degree of stabilization for preoperative assessment of selected low back pain patients. Whether other non-mechanical factors affect the pain relief experienced by the patients remains unknown.

  20. Applications of In Ovo Technique for the Optimal Development of the Gastrointestinal Tract and the Potential Influence on the Establishment of Its Microbiome in Poultry.

    PubMed

    Roto, Stephanie M; Kwon, Young Min; Ricke, Steven C

    2016-01-01

    As the current poultry production system stands, there is a period of time when newly hatched chicks are prevented from access to feed for approximately 48-72 h. Research has indicated that this delay in feeding may result in decreased growth performance when compared to chicks that are fed immediately post-hatch. To remedy this issue, in ovo methodology may be applied in order to supply the embryo with additional nutrients prior to hatching and those nutrients will continue to be utilized by the chick post-hatch during the fasting period. Furthermore, in ovo injection of various biologics have been researched based on the ability of not only supplying the chick embryo with additional nutrients that would promote improved growth but also compounds that may benefit the future health of the chicken host. Such compounds include various immunostimulants, live beneficial bacteria, prebiotics, and synbiotics. However, it is important to determine the site and age of the in ovo injection for the most productive effects. The primary focus of the current review is to address these two issues [the most effective site(s) and age(s) of in ovo injection] as well as provide the framework for the development of the gastrointestinal tract (GIT) of the chick embryo. Additionally, recent research suggests the colonization of the microbiota in the developing chick may occur during the late stages of embryogenesis. Therefore, we will also discuss the potentials of the in ovo injection method in establishing a healthy and diverse community of microorganisms to colonize the developing GIT that will provide both protection from pathogen invasion and improvement in growth performance to developing chicks. PMID:27583251

  1. Applications of In Ovo Technique for the Optimal Development of the Gastrointestinal Tract and the Potential Influence on the Establishment of Its Microbiome in Poultry

    PubMed Central

    Roto, Stephanie M.; Kwon, Young Min; Ricke, Steven C.

    2016-01-01

    As the current poultry production system stands, there is a period of time when newly hatched chicks are prevented from access to feed for approximately 48–72 h. Research has indicated that this delay in feeding may result in decreased growth performance when compared to chicks that are fed immediately post-hatch. To remedy this issue, in ovo methodology may be applied in order to supply the embryo with additional nutrients prior to hatching and those nutrients will continue to be utilized by the chick post-hatch during the fasting period. Furthermore, in ovo injection of various biologics have been researched based on the ability of not only supplying the chick embryo with additional nutrients that would promote improved growth but also compounds that may benefit the future health of the chicken host. Such compounds include various immunostimulants, live beneficial bacteria, prebiotics, and synbiotics. However, it is important to determine the site and age of the in ovo injection for the most productive effects. The primary focus of the current review is to address these two issues [the most effective site(s) and age(s) of in ovo injection] as well as provide the framework for the development of the gastrointestinal tract (GIT) of the chick embryo. Additionally, recent research suggests the colonization of the microbiota in the developing chick may occur during the late stages of embryogenesis. Therefore, we will also discuss the potentials of the in ovo injection method in establishing a healthy and diverse community of microorganisms to colonize the developing GIT that will provide both protection from pathogen invasion and improvement in growth performance to developing chicks. PMID:27583251

  2. Critical importance of appropriate fixation conditions for faithful imaging of receptor microclusters

    PubMed Central

    Stanly, Tess A.; Fritzsche, Marco; Banerji, Suneale; García, Esther; Bernardino de la Serna, Jorge; Jackson, David G.

    2016-01-01

    ABSTRACT Receptor clustering is known to trigger signalling events that contribute to critical changes in cellular functions. Faithful imaging of such clusters by means of fluorescence microscopy relies on the application of adequate cell fixation methods prior to immunolabelling in order to avoid artefactual redistribution by the antibodies themselves. Previous work has highlighted the inadequacy of fixation with paraformaldehyde (PFA) alone for efficient immobilisation of membrane-associated molecules, and the advantages of fixation with PFA in combination with glutaraldehyde (GA). Using fluorescence microscopy, we here highlight how inadequate fixation can lead to the formation of artefactual clustering of receptors in lymphatic endothelial cells, focussing on the transmembrane hyaluronan receptors LYVE-1 and CD44, and the homotypic adhesion molecule CD31, each of which displays their native diffuse surface distribution pattern only when visualised with the right fixation techniques, i.e. PFA/GA in combination. Fluorescence recovery after photobleaching (FRAP) confirms that the artefactual receptor clusters are indeed introduced by residual mobility. In contrast, we observed full immobilisation of membrane proteins in cells that were fixed and then subsequently permeabilised, irrespective of whether the fixative was PFA or PFA/GA in combination. Our study underlines the importance of choosing appropriate sample preparation protocols for preserving authentic receptor organisation in advanced fluorescence microscopy. PMID:27464671

  3. Critical importance of appropriate fixation conditions for faithful imaging of receptor microclusters.

    PubMed

    Stanly, Tess A; Fritzsche, Marco; Banerji, Suneale; García, Esther; Bernardino de la Serna, Jorge; Jackson, David G; Eggeling, Christian

    2016-01-01

    Receptor clustering is known to trigger signalling events that contribute to critical changes in cellular functions. Faithful imaging of such clusters by means of fluorescence microscopy relies on the application of adequate cell fixation methods prior to immunolabelling in order to avoid artefactual redistribution by the antibodies themselves. Previous work has highlighted the inadequacy of fixation with paraformaldehyde (PFA) alone for efficient immobilisation of membrane-associated molecules, and the advantages of fixation with PFA in combination with glutaraldehyde (GA). Using fluorescence microscopy, we here highlight how inadequate fixation can lead to the formation of artefactual clustering of receptors in lymphatic endothelial cells, focussing on the transmembrane hyaluronan receptors LYVE-1 and CD44, and the homotypic adhesion molecule CD31, each of which displays their native diffuse surface distribution pattern only when visualised with the right fixation techniques, i.e. PFA/GA in combination. Fluorescence recovery after photobleaching (FRAP) confirms that the artefactual receptor clusters are indeed introduced by residual mobility. In contrast, we observed full immobilisation of membrane proteins in cells that were fixed and then subsequently permeabilised, irrespective of whether the fixative was PFA or PFA/GA in combination. Our study underlines the importance of choosing appropriate sample preparation protocols for preserving authentic receptor organisation in advanced fluorescence microscopy. PMID:27464671

  4. Methanol fixation of plant tissue for Scanning Electron Microscopy improves preservation of tissue morphology and dimensions

    PubMed Central

    2013-01-01

    Background It is well known that preparation of biological (plant and animal) tissues for Scanning Electron Microscopy (SEM) by chemical fixation and critical point drying results in shrinkage of tissues, often by up to 20-30%, depending on the tissue type and fixation protocol used. We sought to identify a protocol that would preserve tissue size and morphology better than standard chemical fixatives and dehydration regimes. We compared a range of processing techniques by quantifying changes in tissue size and recording details of surface morphology using leaf tissues from three commonly studied species; Arabidopsis thaliana, barley and cotton. Results All processing protocols altered tissue dimensions. Methanol fixation and dehydration, followed by a further short (1 h) dehydration step in ethanol and critical point drying (which was based on a previously published method), preserved tissue dimensions most consistently of all protocols tested, although it did cause 8% shrinkage in all three species. This protocol was also best for preservation of surface morphology in all three species. We outline a recommended protocol and advise that the method is best trialled for different tissues, especially thicker or larger samples. Conclusions This study shows that simultaneous fixation and dehydration in methanol followed by ethanol results in better preservation of dimensions and morphology of critical point dried plant tissues than other fixation and dehydration procedures. It is a quick and simple method, and requires standard SEM preparation equipment. PMID:24083940

  5. SR and LR Union Suture for the Treatment of Myopic Strabismus Fixus: Is Scleral Fixation Necessary?

    PubMed Central

    Lam, Carol P. S.; Yam, Jason C. S.; Lau, Flora H. S.; Fan, Dorothy S. P.; Wong, C. Y.; Yu, Christopher B. O.; Lau, Winnie W. Y.

    2015-01-01

    Purpose. To evaluate and compare the effectiveness of scleral fixation SR and LR union suture and nonscleral fixation union suture for the treatment of myopic strabismus fixus. Methods. Retrospective review of 32 eyes of 22 patients with myopic strabismus fixus who had undergone union suture of superior rectus (SR) and lateral rectus (LR) with or without scleral fixation, and follow-up longer than 6 months at Hong Kong Eye Hospital from 2006 to 2013. Surgical techniques and outcomes in terms of ocular alignment are analyzed. Results. There is significant overall improvement both in postoperative angle of esodeviation (P < 0.01) and postoperative range of movement (P = 0.042). Comparing between the sclera fixation group (11 eyes) versus nonscleral fixation group (21 eyes), the postoperative horizontal deviation, the postoperative vertical deviation, successful outcome, and the change in horizontal deviation were not significantly different (P > 0.05). Conclusions. Union suture of SR and LR is an effective procedure in correcting myopic strabismus fixus. Fixation of the union suture to the sclera does not improve surgical outcome. PMID:25954751

  6. 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…

  7. External Fixation of Open Humerus Factures

    PubMed Central

    Marsh, JL; Mahoney, Craig R; Steinbronn, Dave

    1999-01-01

    Fifteen patients with open shaft of humerus fractures were treated with a monolateral external fixator. Nine patients presented with nerve palsies. Two radial nerves were disrupted and required grafting. Of the seven others, six spontaneously recovered and one brachial plexus partially improved. All fractures healed. The average duration of external fixation was 21 weeks. Four patients required additional procedures prior to healing (external fixator reapplication - 2, plating and bone grafting - 2). Two of these four experienced breakage of 4.5 mm external fixation pins. Eight patients developed pin tract infections, which all resolved with local care and antibiotics. Thirteen patients were contacted at an average of 63 months after injury. Eleven reported they were satisfied with their result, nine had no functional limits, and eight reported no pain. PMID:10847515

  8. 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

  9. 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

  10. 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.

  11. 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

  12. New analytical technique for establishing the quality of Soil Organic Matter affected by a wildfire. A first approach using Fourier transform ion cyclotron resonance mass spectrometry

    NASA Astrophysics Data System (ADS)

    Jiménez-Morillo, Nicasio T.; González-Pérez, José A.; Waggoner, Derek C.; Almendros, Gonzalo; González-Vila, Francisco J.; Hatcher, Patrick G.

    2016-04-01

    Introduction: Fire is one of the most important modulator factors of the environment and the forest. It is able to induce chemical and biological shifts and these, in turn, can alter the physical properties of soil. Generally, fire affects the most reactive fraction, soil organic matter (SOM) (González-Pérez et al., 2004) resulting in changes to several soil properties and functions. To study changes in SOM following a wildfire, researchers can count on several traditional as well as new analytical techniques. One of the most recently employed techniques is Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). This new powerful ultra-high resolution mass spectral technique, together with graphic interpretation tools such as van Krevelen diagrams (Kim et al, 2003), may be used to shed light on alterations caused by the burning of SOM. The objective of this research is to study fire impacts on SOM, using a sandy soil collected under a Cork oak (Quercus suber) in Doñana National Park, Southwest Spain. that was affected by a wildfire in August 2012. Methods: The impact of fire on SOM was studied in various different sieve fractions (coarse, 1-2 mm, and fine, <0.05 mm) collected in a burned area and an adjacent unburned control site with the same physiographic conditions. Alkaline extracts of SOM from each soil sample were examined using a Bruker Daltonics 12 Tesla Apex Qe FT-ICR-MS equipped with an Apollo II ESI ion source (operating in negative ion mode). The ESI voltages were optimized for each sample, and all spectra were internally calibrated following the procedure of (Sleighter and Hatcher, 2007), after which, peaks were assigned unique molecular formulas using a MatLab script written in house by Dr. Wassim Obeid of Old Dominion University. Results: The van Krevelen diagrams together with the relative intensity of each chemical compound, both obtained by FT-ICR-MS, allowed us to assess SOM quality for each sample and size fractions. The

  13. New analytical technique for establishing the quality of Soil Organic Matter affected by a wildfire. A first approach using Fourier transform ion cyclotron resonance mass spectrometry

    NASA Astrophysics Data System (ADS)

    Jiménez-Morillo, Nicasio T.; González-Pérez, José A.; Waggoner, Derek C.; Almendros, Gonzalo; González-Vila, Francisco J.; Hatcher, Patrick G.

    2016-04-01

    Introduction: Fire is one of the most important modulator factors of the environment and the forest. It is able to induce chemical and biological shifts and these, in turn, can alter the physical properties of soil. Generally, fire affects the most reactive fraction, soil organic matter (SOM) (González-Pérez et al., 2004) resulting in changes to several soil properties and functions. To study changes in SOM following a wildfire, researchers can count on several traditional as well as new analytical techniques. One of the most recently employed techniques is Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). This new powerful ultra-high resolution mass spectral technique, together with graphic interpretation tools such as van Krevelen diagrams (Kim et al, 2003), may be used to shed light on alterations caused by the burning of SOM. The objective of this research is to study fire impacts on SOM, using a sandy soil collected under a Cork oak (Quercus suber) in Doñana National Park, Southwest Spain. that was affected by a wildfire in August 2012. Methods: The impact of fire on SOM was studied in various different sieve fractions (coarse, 1-2 mm, and fine, <0.05 mm) collected in a burned area and an adjacent unburned control site with the same physiographic conditions. Alkaline extracts of SOM from each soil sample were examined using a Bruker Daltonics 12 Tesla Apex Qe FT-ICR-MS equipped with an Apollo II ESI ion source (operating in negative ion mode). The ESI voltages were optimized for each sample, and all spectra were internally calibrated following the procedure of (Sleighter and Hatcher, 2007), after which, peaks were assigned unique molecular formulas using a MatLab script written in house by Dr. Wassim Obeid of Old Dominion University. Results: The van Krevelen diagrams together with the relative intensity of each chemical compound, both obtained by FT-ICR-MS, allowed us to assess SOM quality for each sample and size fractions. The

  14. Nitrogen fixation and CO/sub 2/ metabolism: proceedings

    SciTech Connect

    Ludden, P.W.; Burris, J.E.

    1985-01-01

    Photosynthesis and nitrogen fixation are key metabolic processes which lead to the production of reduced carbon and nitrogen compounds. These compounds are essential for the maintenance and continuation of life on earth. In this volume many recent advances in the study of nitrogen fixation and photosynthetic carbon dioxide fixation are presented. The papers were presented in seven sessions. These sessions were the biochemistry of the legume nodule, genetics and molecular biology of nitrogen fixation, enzymes and cofactors involved in inorganic nitrogen reductions, aspects of nitrogen fixation by associations and symbioses, physiology of free-living nitrogen fixers, interactions between carbon metabolism and nitrogen fixation, photorespiration in plants, and photosynthetic carbon fixation. (DT)

  15. 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

  16. 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

  17. 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.

  18. Multifaceted Investigation of Metabolites During Nitrogen Fixation in Medicago via High Resolution MALDI-MS Imaging and ESI-MS

    NASA Astrophysics Data System (ADS)

    Gemperline, Erin; Jayaraman, Dhileepkumar; Maeda, Junko; Ané, Jean-Michel; Li, Lingjun

    2015-01-01

    Legumes have developed the unique ability to establish a symbiotic relationship with soil bacteria known as rhizobia. This interaction results in the formation of root nodules in which rhizobia thrive and reduce atmospheric dinitrogen into plant-usable ammonium through biological nitrogen fixation (BNF). Owing to the availability of genetic information for both of the symbiotic partners, the Medicago truncatula- Sinorhizobium meliloti association is an excellent model for examining the BNF process. Although metabolites are important in this symbiotic association, few studies have investigated the array of metabolites that influence this process. Of these studies, most target only a few specific metabolites, the roles of which are either well known or are part of a well-characterized metabolic pathway. Here, we used a multifaceted mass spectrometric (MS) approach to detect and identify the key metabolites that are present during BNF using the Medicago truncatula- Sinorhizobium meliloti association as the model system. High mass accuracy and high resolution matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) Orbitrap instruments were used in this study and provide complementary results for more in-depth characterization of the nitrogen-fixation process. We used well-characterized plant and bacterial mutants to highlight differences between the metabolites that are present in functional versus nonfunctional nodules. Our study highlights the benefits of using a combination of mass spectrometric techniques to detect differences in metabolite composition and the distributions of these metabolites in plant biology.

  19. Use of a locking compression plate as an external fixator for repair of a tarsometatarsal fracture in a bald eagle (Haliaeetus leucocephalus).

    PubMed

    Montgomery, Ronald D; Crandall, Elizabeth; Bellah, Jamie R

    2011-06-01

    We describe the successful treatment of a tarsometatarsal fracture in a mature bald eagle (Haliaeetus leucocephalus) using a locking compression plate as an external fixator. The anatomy of the area (inelastic dermis and minimal subcutaneous space) and the high forces placed on a fracture at that site necessitated a unique approach to fixation. The unconventional use of a locking compression plate as an external fixator was minimally invasive, well tolerated by the eagle, and provided adequate stability in opposing fracture forces. This technique may serve as a method of fixation for tarsometatarsal fractures in other large avian species.

  20. Use of a locking compression plate as an external fixator for repair of a tarsometatarsal fracture in a bald eagle (Haliaeetus leucocephalus).

    PubMed

    Montgomery, Ronald D; Crandall, Elizabeth; Bellah, Jamie R

    2011-06-01

    We describe the successful treatment of a tarsometatarsal fracture in a mature bald eagle (Haliaeetus leucocephalus) using a locking compression plate as an external fixator. The anatomy of the area (inelastic dermis and minimal subcutaneous space) and the high forces placed on a fracture at that site necessitated a unique approach to fixation. The unconventional use of a locking compression plate as an external fixator was minimally invasive, well tolerated by the eagle, and provided adequate stability in opposing fracture forces. This technique may serve as a method of fixation for tarsometatarsal fractures in other large avian species. PMID:21877449

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. Collaborative study for establishment of a European Pharmacopoei Biological Reference Preparation (BRP) for B19 virus DNA testing of plasma pools by nucleic acid amplification technique.

    PubMed

    Nübling, C M; Daas, A; Buchheit, K H

    2004-01-01

    The goal of the collaborative study was to calibrate the B19 DNA content of a candidate Biological Reference Preparation (BRP) that is intended to be used for the validation of the analytical procedure, as threshold control and/or as quantitative reference material in the Nucleic Acid Amplification Technique (NAT) test of plasma pools for detection of B19 contamination. The candidate BRP was calibrated against the 1st International Standard for B19 DNA NAT assays. According to the European Pharmacopoeia monograph Human anti-D immunoglobulin, the threshold control needs to have a titre of 10( 4) IU/ml of B19 virus DNA. The lyophilised candidate BRP was prepared from 0.5 ml aliquots of a plasma pool spiked with B19 virus. The B19 virus originated from a "B19 virus window phase" blood donation (anti-B19 negative, B19-DNA high titre positive) and was diluted in a plasma pool tested negative by both serological and NAT assays for Hepatitis B Virus, Hepatitis C Virus and Human Immunodeficiency Virus 1 to obtain a B19-DNA concentration level in the range of 10( 6) copies/ml. The residual water content of the lyophilised candidate BRP was determined as 0.98 +/- 0.65% (mean +/- relative standard deviation). Sixteen laboratories (Official Medicine Control Laboratories, manufacturers of plasma derivatives, NAT test laboratories and NAT kit manufacturers) from nine countries participated. Participants were requested to test the candidate BRP and the International Standard (99/800) in four independent test runs on different days using their in-house qualitative and/or quantitative NAT methods. Sixteen laboratories reported results. Thirteen laboratories reported results from qualitative assays and 5 laboratories reported results from quantitative assays. Two laboratories reported results from both types of assay. For the qualitative assays a weighted combined potency of 5.64 log( 10) IU/ml with 95 per cent confidence limits of +/- 0.17 log( 10) which corresponds to 67 to 150

  6. Collaborative study for establishment of a European Pharmacopoei Biological Reference Preparation (BRP) for B19 virus DNA testing of plasma pools by nucleic acid amplification technique.

    PubMed

    Nübling, C M; Daas, A; Buchheit, K H

    2004-01-01

    The goal of the collaborative study was to calibrate the B19 DNA content of a candidate Biological Reference Preparation (BRP) that is intended to be used for the validation of the analytical procedure, as threshold control and/or as quantitative reference material in the Nucleic Acid Amplification Technique (NAT) test of plasma pools for detection of B19 contamination. The candidate BRP was calibrated against the 1st International Standard for B19 DNA NAT assays. According to the European Pharmacopoeia monograph Human anti-D immunoglobulin, the threshold control needs to have a titre of 10( 4) IU/ml of B19 virus DNA. The lyophilised candidate BRP was prepared from 0.5 ml aliquots of a plasma pool spiked with B19 virus. The B19 virus originated from a "B19 virus window phase" blood donation (anti-B19 negative, B19-DNA high titre positive) and was diluted in a plasma pool tested negative by both serological and NAT assays for Hepatitis B Virus, Hepatitis C Virus and Human Immunodeficiency Virus 1 to obtain a B19-DNA concentration level in the range of 10( 6) copies/ml. The residual water content of the lyophilised candidate BRP was determined as 0.98 +/- 0.65% (mean +/- relative standard deviation). Sixteen laboratories (Official Medicine Control Laboratories, manufacturers of plasma derivatives, NAT test laboratories and NAT kit manufacturers) from nine countries participated. Participants were requested to test the candidate BRP and the International Standard (99/800) in four independent test runs on different days using their in-house qualitative and/or quantitative NAT methods. Sixteen laboratories reported results. Thirteen laboratories reported results from qualitative assays and 5 laboratories reported results from quantitative assays. Two laboratories reported results from both types of assay. For the qualitative assays a weighted combined potency of 5.64 log( 10) IU/ml with 95 per cent confidence limits of +/- 0.17 log( 10) which corresponds to 67 to 150

  7. Applying Cross-Pin System in Both Femoral and Tibial Fixation in Anterior Cruciate Ligament Reconstruction Using Hamstring Tendons.

    PubMed

    Qi, Wei; Liu, Yujie; Xue, Jing; Li, Haifeng; Wang, Junliang; Qu, Feng

    2015-10-01

    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

  8. THE ROLE OF FIBRIN GLUE AND SUTURE ON THE FIXATION OF ULTRA FROZEN PRESERVED MENISCUS TRANSPLANTATION IN RABBITS

    PubMed Central

    Reckers, Leandro José; Fagundes, Djalma José; Pozo Raymundo, José Luiz; Granata Júnior, Geraldo Sérgio de Mello; Moreira, Márcia Bento; Paiva, Vanessa Carla; Negrini Fagundes, Anna Luiza; Cohen, Moises

    2015-01-01

    Objective: To evaluate the ability of fibrin adhesive in promoting the meniscus fixation within two, four and eight weeks compared to the conventional soft-tissue suture technique. Materials and Methods: 36 right medial menisci of rabbits preserved at negative 73° Celsius for 30 days were transplanted to animals of the same sample and fixed with soft-tissue suture or fibrin glue. After 2, 4 or 8 weeks, the appearance of the menisci and the quality of fixation were macroscopically checked and evaluated by a scoring system. The findings were subjected to the statistical study of variance analysis (p ≤ 0.05%). Results: The deep-frozen meniscus preservation maintained the integrity of the meniscus transplant, and, macroscopically, there was no significant reduction of the length of the meniscus in all post-transplant periods (p = 0.015). The menisci fixed with fibrin showed slight changes in color and surface roughness. There were no signs of rejection or infection in both groups. Suture fixation scoring was superior (p = 0.015) in all periods (80% of total fixation) as compared to the setting promoted by fibrin (20% of total fixation). Conclusion: The homologous transplantation of the meniscus of rabbits experienced various degrees of integration to the knee according to the fixation method; the surgical soft tissues suturing technique was shown to be superior in the evaluation of scores compared to the fixation with fibrin adhesive. PMID:27004186

  9. 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

  10. Hip Labral Reconstruction: The "Kite Technique" for Improved Efficiency and Graft Control.

    PubMed

    Bhatia, Sanjeev; Chahla, Jorge; Dean, Chase S; Ellman, Michael B

    2016-04-01

    Although the merits of labral reconstruction have been well established, the technical difficulty of presently used reconstruction techniques-particularly with graft passage and fixation-limit its efficacy and potentiates the risk of iatrogenic damage within the hip joint. The unwieldy nature of a floating labral graft anchored on one end may impede accurate fixation of the other end, which is critical for restoration of the fluid hip seal and preservation of graft integrity. In this technique narrative, we present a "kite technique" for introduction, control, and efficient fixation of a labral reconstruction graft. The principles of this method are founded on the belief that a soft-tissue graft in an arthroscopic environment is much easier to guide into position with 2 control sutures using a pulley system similar to flying a kite with 2 fly lines. Although we herein detail the technique as it applies to labral reconstruction in the hip, the concept of the kite technique may also be employed in arthroscopic-assisted soft-tissue reconstructions of other joints. PMID:27354954

  11. Design Fixation in the Wild: Design Environments and Their Influence on Fixation

    ERIC Educational Resources Information Center

    Youmans, Robert J.

    2011-01-01

    Many studies of design fixation ask designers to work in controlled laboratory or classroom environments, but innovative design work frequently occurs in dynamic, social environments. The two studies reviewed in this paper investigated how three independent variables likely to be present in many design environments affect design fixation. The…

  12. Fixation location effects on fixation durations during reading: an inverted optimal viewing position effect.

    PubMed

    Vitu, F; McConkie, G W; Kerr, P; O'Regan, J K

    2001-01-01

    Previous research has found that words are identified most quickly when the eyes are near their center (the Optimal Viewing Position effect). A study was conducted to determine whether this same phenomenon is observed during reading, as revealed by a relationship between fixation position in a word and the duration of the fixation. An analysis of three large existing corpora of eye movement data, two from adults and one from children, showed a surprising inverted Optimal Viewing Position curve: mean fixation duration is greatest, rather than lowest, when the eyes were at the centers of words. From this phenomenon, we suggest an alternative explanation to the fixation duration trade-off effect in word refixations [O'Regan & Lévy-Schoen, Attention and performance XII: the psychology of reading (1987)]; the phenomenon also contradicts expectations of both oculomotor and cognitive theories of eye movement control. Attempts to test alternative explanations led to the discovery of another phenomenon, the Saccade Distance effect: mean fixation durations vary with the distance of the prior fixation from the currently-fixated word, being longer with greater distances. The durations of fixations in reading are complexly determined, with influences both from language and perceptual/oculomotor levels.

  13. Late extensor pollicis longus rupture following plate fixation in Galeazzi fracture dislocation.

    PubMed

    Sabat, Dhananjaya; Dabas, Vineet; Dhal, Anil

    2014-07-01

    Late rupture of extensor pollicis longus (EPL) tendon after Galeazzi fracture dislocation fixation is an unknown entity though it is a well-established complication following distal radius fractures. We report the case of a 55-year old male who presented with late EPL tendon rupture 4 months following internal fixation of Galeazzi fracture dislocation with a Locking Compression Plate (LCP). He was managed with extensor indicis proprius (EIP) transfer to restore thumb extension. At 4 years followup, functional result of the transfer was good. We identify possible pitfalls with this particular patient and discuss how to avoid them in future.

  14. Automatic versus manual lymphocyte fixation: impact on dose estimation using the cytokinesis-block micronucleus assay.

    PubMed

    Beinke, Christina; Port, Matthias; Abend, Michael

    2015-03-01

    The lymphocyte cytokinesis-block micronucleus (CBMN) assay is a biodosemeter for the exposure to ionizing radiation. We examined the feasibility to implement a fully automated cell harvesting system for binucleate lymphocyte (BN) fixation. We compared fully automated versus manual BN fixation and evaluated its relevance on the accuracy of dose estimates using the CBMN. First, dose-response curves based on X-ray irradiated blood samples of ten healthy donors (0-4 Gy, dose rate 1.0 Gy/min) were established. BN was either prepared manually or fully automatically using the Hanabi cell harvester system PII. Slides were finally scored following an automatic or semi-automatic approach using the Metafer4 platform. The variance was calculated per dose and separately for each of the four fixation and scoring combinations. Thereafter, a serial of 16 blood samples of unknown exposure doses (0-3.9 Gy X-ray) was analyzed. Employing the four fixation and scoring combinations, we compared the number of dose estimates lying outside the ±0.5 Gy interval and the mean absolute difference (MAD) and examined sensitivity, specificity and accuracy of doses merged into binary dose categories of clinical significance. Irrespective of the fixation procedure, we observed at doses ≤1.0 Gy about 2-4 times higher median variances for the automated scoring procedure over the semi-automated approach (p ≤ 0.03). The lowest median variance was observed for automatic fixation + semi-automated scoring (135) which was even 2 times lower relative to manual fixation + semi-automated scoring (276, p = 0.04). These differences became negligible after doses >1.0 Gy. For the automatic fixation procedure, we also observed a tendency toward borderline significant higher numbers of dose estimates falling into the ±0.5 Gy interval (25 %, p = 0.08) and lower MAD values (50 %, p = 0.09), which was predominantly caused by the accuracy of dose assessment >1.0 Gy. Regarding the

  15. Updated Outcomes of Prophylactic Femoral Fixation.

    PubMed

    Kreul, Sarah M; Sorger, Joel I; Rajamanickam, Victoria P; Heiner, John P

    2016-01-01

    Despite an increasing number of patients with metastatic bone disease (MBD), minimal data exist regarding outcomes of patients undergoing prophylactic femoral fixation for MBD when compared with other frequently performed orthopedic operations, such as hemiarthroplasty of the femur. The authors performed a retrospective database review evaluating these procedures due to similar operative times and patient populations and also reviewed common comorbidities such as body mass index (BMI). The goal was to provide updated results of prophylactic femoral fixation and evaluate whether certain patient risk factors (eg, BMI) altered 30-day survival for patients with MBD. The authors reviewed 1849 patients with and without MBD treated by prophylactic fixation and hemiarthroplasty from 2006 to 2011 identified in the American College of Surgeons National Surgical Quality Improvement Program database. There were no significant differences in complications between patients undergoing surgical treatment for impending or actual femoral fracture. In addition, there were no differences between the 217 patients with MBD in either the hemiarthroplasty or prophylactic fixation groups because the rate of death within 30 days postoperatively was 5.56% and 3.30%, respectively (P=.526). When comparing BMI, obese patients had higher rates of wound infection, and underweight patients were more likely to develop pneumonia or die within 30 days postoperatively. Patients with impending femur fractures benefit from prophylactic fixation and perform as well in the short term as patients undergoing hemiarthroplasty. Certain BMI categories (underweight or obese) contributed to poorer outcomes. These findings provide updated information for discussing risks and benefits with surgical candidates.

  16. Note upon steady visual fixation and repeated auditory stimulation in meditation and the laboratory.

    PubMed

    Piggins, D; Morgan, D

    1977-04-01

    The techniques of steady visual fixation and repetitious auditory input are used in the laboratory for investigating perceptual phenomena and in yoga and meditation for facilitating altered states of awareness. Phenomena related to mild sensory deprivation are reported in both circumstances.

  17. Extraperiosteal Dual Plate Fixation of Acute Mid-Shaft Clavicle Fractures: A Technical Trick.

    PubMed

    Shannon, Steven F; Chen, Xiaobin; Torchia, Michael; Schoch, Bradley

    2016-10-01

    Historically, surgical treatment of acute mid-shaft clavicle fractures has excellent outcomes with low rates of nonunion. More complex fracture patterns with significant comminution may limit the fixation that can be obtained with a single plate. The authors describe the surgical technique and case series of patients treated with extraperiosteal dual plating for acute mid-shaft clavicle fractures.

  18. The Role of Symbiotic Nitrogen Fixation in Sustainable Production of Biofuels

    PubMed Central

    Biswas, Bandana; Gresshoff, Peter M.

    2014-01-01

    With the ever-increasing population of the world (expected to reach 9.6 billion by 2050), and altered life style, comes an increased demand for food, fuel and fiber. However, scarcity of land, water and energy accompanied by climate change means that to produce enough to meet the demands is getting increasingly challenging. Today we must use every avenue from science and technology available to address these challenges. The natural process of symbiotic nitrogen fixation, whereby plants such as legumes fix atmospheric nitrogen gas to ammonia, usable by plants can have a substantial impact as it is found in nature, has low environmental and economic costs and is broadly established. Here we look at the importance of symbiotic nitrogen fixation in the production of biofuel feedstocks; how this process can address major challenges, how improving nitrogen fixation is essential, and what we can do about it. PMID:24786096

  19. Modified arthroscopic suture fixation of a displaced tibial eminence fracture.

    PubMed

    Lehman, Ronald A; Murphy, Kevin P; Machen, M Shaun; Kuklo, Timothy R

    2003-02-01

    This study describes a new arthroscopic method using a whip-stitch technique for treating a displaced type III tibial eminence fracture. A 12-year-old girl who sustained a displaced type III tibial eminence fracture was treated with arthroscopic fixation using the Arthrosew disposable suture device (Surgical Dynamics, Norwalk, CT) to place a whip stitch into the anterior cruciate ligament (ACL). The Arthrex ACL guide (Arthrex, Naples, FL) was used to reduce the avulsed tibial spine fragment. Sutures were then passed through the tibial tunnel and secured over a bony bridge with the knee in 20 degrees of flexion. At 9 months, the patient has a full range of motion with normal Lachman and anterior drawer testing, and she has returned to competitive basketball. Radiographs show complete fracture healing. KT-1000 and isokinetic testing at 9-month follow-up show only minimal side-to-side differences. The Arthrosew device provides a significant advantage in the treatment of type III and IV fractures of the tibial eminence by obtaining arthroscopic fixation within the substance of the ACL, thus obviating arthrotomy and hardware placement. This technique also restores the proper length and tension to the ACL, and provides a simplified, reproducible method of treatment for this injury.

  20. Determinants of eye-fixation duration.

    PubMed

    Salthouse, T A; Ellis, C L

    1980-06-01

    Four variables that might be presumed to contribute to the duration of an eye fixation were investigated in a series of seven experiments. These variables were stimulus processing time, relative emphasis on speed or accuracy, sequential dependencies across successive fixations, and amplitude of the preceding and following saccades. The pattern of results suggested a two-component model to account for the duration of single eye-fixations. One component is the minimum pause time of the eye, estimated to be about 200 msec without any stimulus processing. The second component involves stimulus processing, estimated to require a minimum of 50 to 100 msec, but subject to a number of influences that can substantially increase or decrease this duration. Although the authors did not generate this model to account for eye movements in complex tasks such as reading, they speculate about how complications could be added.

  1. Control and Functions of Fixational Eye Movements

    PubMed Central

    Rucci, Michele; Poletti, Martina

    2016-01-01

    Humans and other species explore a visual scene by rapidly shifting their gaze 2-3 times every second. Although the eyes may appear immobile in the brief intervals in between saccades, microscopic (fixational) eye movements are always present, even when attending to a single point. These movements occur during the very periods in which visual information is acquired and processed and their functions have long been debated. Recent technical advances in controlling retinal stimulation during normal oculomotor activity have shed new light on the visual contributions of fixational eye movements and their degree of control. The emerging body of evidence, reviewed in this article, indicates that fixational eye movements are important components of the strategy by which the visual system processes fine spatial details, enabling both precise positioning of the stimulus on the retina and encoding of spatial information into the joint space-time domain.

  2. Biomechanical Evaluation of Plate Versus Lag Screw Only Fixation of Distal Fibula Fractures.

    PubMed

    Misaghi, Amirhossein; Doan, Josh; Bastrom, Tracey; Pennock, Andrew T

    2015-01-01

    Traditional fixation of unstable Orthopaedic Trauma Association type B/C ankle fractures consists of a lag screw and a lateral or posterolateral neutralization plate. Several studies have demonstrated the clinical success of lag screw only fixation; however, to date no biomechanical comparison of the different constructs has been performed. The purpose of the present study was to evaluate the biomechanical strength of these different constructs. Osteotomies were created in 40 Sawbones(®) distal fibulas and reduced using 1 bicortical 3.5-mm stainless steel lag screw, 2 bicortical 3.5-mm lag screws, 3 bicortical 3.5-mm lag screws, or a single 3.5-mm lag screw coupled with a stainless steel neutralization plate with 3 proximal cortical and 3 distal cancellous screws. The constructs were tested to determine the stiffness in lateral bending and rotation and failure torque. No significant differences in lateral bending or rotational stiffness were detected between the osteotomies fixed with 3 lag screws and a plate. Constructs fixed with 1 lag screw were weaker for both lateral bending and rotational stiffness. Osteotomies fixed with 2 lag screws were weaker in lateral bending only. No significant differences were found in the failure torque. Compared with lag screw only fixation, plate fixation requires larger incisions and increased costs and is more likely to require follow-up surgery. Despite the published clinical success of treating simple Orthopaedic Trauma Association B/C fractures with lag screw only fixation, many surgeons still have concerns about stability. For noncomminuted, long oblique distal fibula fractures, lag screw only fixation techniques offer construct stiffness similar to that of traditional plate and lag screw fixation. PMID:25990534

  3. Biomechanical Evaluation of Plate Versus Lag Screw Only Fixation of Distal Fibula Fractures.

    PubMed

    Misaghi, Amirhossein; Doan, Josh; Bastrom, Tracey; Pennock, Andrew T

    2015-01-01

    Traditional fixation of unstable Orthopaedic Trauma Association type B/C ankle fractures consists of a lag screw and a lateral or posterolateral neutralization plate. Several studies have demonstrated the clinical success of lag screw only fixation; however, to date no biomechanical comparison of the different constructs has been performed. The purpose of the present study was to evaluate the biomechanical strength of these different constructs. Osteotomies were created in 40 Sawbones(®) distal fibulas and reduced using 1 bicortical 3.5-mm stainless steel lag screw, 2 bicortical 3.5-mm lag screws, 3 bicortical 3.5-mm lag screws, or a single 3.5-mm lag screw coupled with a stainless steel neutralization plate with 3 proximal cortical and 3 distal cancellous screws. The constructs were tested to determine the stiffness in lateral bending and rotation and failure torque. No significant differences in lateral bending or rotational stiffness were detected between the osteotomies fixed with 3 lag screws and a plate. Constructs fixed with 1 lag screw were weaker for both lateral bending and rotational stiffness. Osteotomies fixed with 2 lag screws were weaker in lateral bending only. No significant differences were found in the failure torque. Compared with lag screw only fixation, plate fixation requires larger incisions and increased costs and is more likely to require follow-up surgery. Despite the published clinical success of treating simple Orthopaedic Trauma Association B/C fractures with lag screw only fixation, many surgeons still have concerns about stability. For noncomminuted, long oblique distal fibula fractures, lag screw only fixation techniques offer construct stiffness similar to that of traditional plate and lag screw fixation.

  4. The effect of altered macroclimate on N-fixation by boreal feather mosses

    PubMed Central

    Gundale, Michael J.; Wardle, David A.; Nilsson, Marie-Charlotte

    2012-01-01

    Plant productivity is predicted to increase in boreal forests owing to climate change, but this may depend on whether N inputs from biological N-fixation also increases. We evaluated how alteration of climatic factors affects N input from a widespread boreal N-fixer, i.e. cyanobacteria associated with the feather moss Pleurozium schreberi. In each of 10 forest stands in northern Sweden, we established climate-change plots, including a control (ambient climate) plot and three plots experiencing a +2°C temperature increase, an approximately threefold reduction in precipitation frequency, and either 0.07, 0.29 or 1.16 times normal summer precipitation. We monitored N-fixation in these plots five times between 2007 and 2009, and three times in 2010 after climate treatments ended to assess their recovery. Warmer temperatures combined with less frequent precipitation reduced feather moss moisture content and N-fixation rates regardless of total precipitation. After climate treatments ended, recovery of N-fixation rates occurred on the scale of weeks to months, suggesting resilience of N-fixation to changes in climatic conditions. These results suggest that modelling of biological N-inputs in boreal forests should emphasize precipitation frequency and evaporative water loss in conjunction with elevated temperature rather than absolute changes in mean precipitation. PMID:22696285

  5. The effect of altered macroclimate on N-fixation by boreal feather mosses.

    PubMed

    Gundale, Michael J; Wardle, David A; Nilsson, Marie-Charlotte

    2012-10-23

    Plant productivity is predicted to increase in boreal forests owing to climate change, but this may depend on whether N inputs from biological N-fixation also increases. We evaluated how alteration of climatic factors affects N input from a widespread boreal N-fixer, i.e. cyanobacteria associated with the feather moss Pleurozium schreberi. In each of 10 forest stands in northern Sweden, we established climate-change plots, including a control (ambient climate) plot and three plots experiencing a +2°C temperature increase, an approximately threefold reduction in precipitation frequency, and either 0.07, 0.29 or 1.16 times normal summer precipitation. We monitored N-fixation in these plots five times between 2007 and 2009, and three times in 2010 after climate treatments ended to assess their recovery. Warmer temperatures combined with less frequent precipitation reduced feather moss moisture content and N-fixation rates regardless of total precipitation. After climate treatments ended, recovery of N-fixation rates occurred on the scale of weeks to months, suggesting resilience of N-fixation to changes in climatic conditions. These results suggest that modelling of biological N-inputs in boreal forests should emphasize precipitation frequency and evaporative water loss in conjunction with elevated temperature rather than absolute changes in mean precipitation.

  6. The importance of fixation procedures on DNA template and its suitability for solution-phase polymerase chain reaction and PCR in situ hybridization.

    PubMed

    O'Leary, J J; Browne, G; Landers, R J; Crowley, M; Healy, I B; Street, J T; Pollock, A M; Murphy, J; Johnson, M I; Lewis, F A

    1994-04-01

    Conventional solution-phase polymerase chain reaction (PCR) and in situ PCR/PCR in situ hybridization are powerful tools for retrospective analysis of fixed paraffin wax-embedded material. Amplification failure using these techniques is now encountered in some centres using archival fixed tissues. Such 'failures' may not only be due to absent target DNA sequences in the tissues, but may be a direct effect of the type of fixative, fixation time and/or fixation temperature used. The type of nucleic acid extraction procedure applied will also influence amplification results. This is particularly true with in situ PCR/PCR in situ hybridization. To examine these effects in solution-phase PCR, beta-globin gene was amplified in 100 mg pieces of tonsillar tissue fixed in Formal saline, 10% formalin, neutral buffered formaldehyde, Carnoy's Bouin's, buffered formaldehyde sublimate, Zenker's, Helly's and glutaraldehyde at 0 to 4 degrees C, room temperature and 37 degrees C fixation temperatures and for fixation periods of 6, 24, 48 and 72 hours and 1 week. DNA extraction procedures used were simple boiling and 5 days' proteinase K digestion at 37 degrees C. Amplified product was visible primarily yet variably from tissue fixed in neutral buffered formaldehyde and Carnoy's, whereas fixation in mercuric chloride-based fixatives produced consistently negative results. Room temperature and 37 degrees C fixation temperature appeared most conducive to yielding amplifiable DNA template. Fixation times of 24 and 48 hours in neutral buffered formaldehyde and Carnoy's again favoured amplification.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. What's left? An eye movement study of the influence of interword spaces to the left of fixation during reading.

    PubMed

    Jordan, Timothy R; McGowan, Victoria A; Paterson, Kevin B

    2013-06-01

    In English and other alphabetic systems read from left to right, the useful information acquired during each fixational pause is generally reported to extend 14-15 character spaces to the right of each fixation, but only 3-4 character spaces to the left, and certainly no farther than the beginning of the fixated word. However, this leftward extent is remarkably small and seems inconsistent with the general bilateral symmetry of vision. Accordingly, in the present study we investigated the influence of a fundamental component of text to the left of fixation-interword spaces-using a well-established eyetracking paradigm in which invisible boundaries were set up along individual sentence displays that were then read. Each boundary corresponded to the leftmost edge of a word in a sentence, so that as the eyes crossed a boundary, interword spaces in the text to the left of that word were obscured (by inserting a letter x). The proximity of the obscured text during each fixational pause was maintained at one, two, three, or four interword spaces from the left boundary of each fixated word. Normal fixations, regressions, and progressive saccades were disrupted when the obscured text was up to three interword spaces (an average of over 12 character spaces) away from the fixated word, while four interword spaces away produced no disruption. These findings suggest that influential information from text is acquired during each fixational pause from much farther leftward than is generally realized and that this information contributes to normal reading performance. Implications of these findings for reading are discussed.

  8. Engineering the Cyanobacterial Carbon Concentrating Mechanism for Enhanced CO2 Capture and Fixation

    SciTech Connect

    Sandh, Gustaf; Cai, Fei; Shih, Patrick; Kinney, James; Axen, Seth; Salmeen, Annette; Zarzycki, Jan; Sutter, Markus; Kerfeld, Cheryl

    2011-06-02

    In cyanobacteria CO2 fixation is localized in a special proteinaceous organelle, the carboxysome. The CO2 fixation enzymes are encapsulated by a selectively permeable protein shell. By structurally and functionally characterizing subunits of the carboxysome shell and the encapsulated proteins, we hope to understand what regulates the shape, assembly and permeability of the shell, as well as the targeting mechanism and organization of the encapsulated proteins. This knowledge will be used to enhance CO2 fixation in both cyanobacteria and plants through synthetic biology. The same strategy can also serve as a template for the production of modular synthetic bacterial organelles. Our research is conducted using a variety of techniques such as genomic sequencing and analysis, transcriptional regulation, DNA synthesis, synthetic biology, protein crystallization, Small Angle X-ray Scattering (SAXS), protein-protein interaction assays and phenotypic characterization using various types of cellular imaging, e.g. fluorescence microscopy, Transmission Electron Microscopy (TEM), and Soft X-ray Tomography (SXT).

  9. The Weak Link in Anterior Cruciate Ligament Reconstruction: What is the Evidence for Graft Fixation Devices?

    PubMed

    Campbell, Kirk A; Looze, Christopher; Bosco, Joseph A; Strauss, Eric J

    2016-03-01

    Anterior cruciate ligament (ACL) rupture is a common injury that mostly affects young adults. The mechanisms of injury and surgical treatment have been extensively studied in both the laboratory and clinical arenas; however, great controversy still exists in regards to the best surgical technique, graft choice, and graft fixation device. In the area graft fixation, multiple breakthroughs have occurred in terms of fixation devices. These devices generally fall within the broad categories of interference screw, cross-pins, or cortical-based devices. Furthermore, some of these devices are available in either metal or bioabsorbable materials, which adds to the already great variety of options. Although biomechanically these devices have been shown to be able to withstand the typical forces experienced by the ACL graft during the early phases of rehabilitation before the graft has fully incorporated into the bone, little is known about the clinical outcomes. It is well recognized that graft fixation is the weakest link in the early postoperative period after ACL reconstruction. This review of the outcomes of ACL fixation devices explores some of the evidence available for the different devices. PMID:26977545

  10. Comparison of two-transsacral-screw fixation versus triangular osteosynthesis for transforaminal sacral fractures.

    PubMed

    Min, Kyong S; Zamorano, David P; Wahba, George M; Garcia, Ivan; Bhatia, Nitin; Lee, Thay Q

    2014-09-01

    Transforaminal pelvic fractures are high-energy injuries that are translationally and rotationally unstable. This study compared the biomechanical stability of triangular osteosynthesis vs 2-transsacral-screw fixation in the repair of a transforaminal pelvic fracture model. A transforaminal fracture model was created in 10 cadaveric lumbopelvic specimens. Five of the specimens were stabilized with triangular osteosynthesis, which consisted of unilateral L5-to-ilium lumbopelvic fixation and ipsilateral iliosacral screw fixation. The remaining 5 were stabilized with a 2-transsacral-screw fixation technique that consisted of 2 transsacral screws inserted across S1. All specimens were loaded cyclically and then loaded to failure. Translation and rotation were measured using the MicroScribe 3D digitizing system (Revware Inc, Raleigh, North Carolina). The 2-transsacral-screw group showed significantly greater stiffness than the triangular osteosynthesis group (2-transsacral-screw group, 248.7 N/mm [standard deviation, 73.9]; triangular osteosynthesis group, 125.0 N/mm [standard deviation, 66.9]; P=.02); however, ultimate load and rotational stiffness were not statistically significant. Compared with triangular osteosynthesis fixation, the use of 2 transsacral screws provides a comparable biomechanical stability profile in both translation and rotation. This newly revised 2-transsacral-screw construct offers the traumatologist an alternative method of repair for vertical shear fractures that provides biplanar stability. It also offers the advantage of percutaneous placement in either the prone or supine position.

  11. RANDOMIZED PROSPECTIVE STUDY COMPARING TRANSVERSE AND EXTRACORTICAL FIXATION IN ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

    PubMed Central

    da Silva Guarilha, Eduardo; de Andrade Fígaro Caldeira, Paulo Roberto; de Almeida Lira Neto, Ozorio; Navarro, Marcelo Schmidt; Milani, Antonio; Filho, Mario Carneiro

    2015-01-01

    Objective: This study had the objective of prospectively comparing transverse fixation (Cross-Pin™) with extracortical fixation (EZLoc™) for the femur, in surgical reconstruction of the anterior cruciate ligament, from a clinical, biomechanical and functional point of view. Methods: Between April 2007 and November 2009, 50 patients with acute or chronic anterior cruciate ligament injuries underwent arthroscopic reconstruction using the homologous flexor tendons (gracilis and semitendinosus). Randomization of the femoral fixation method was done by means of a draw at the time of the procedure. Patients were excluded if they presented multiple ligament lesions, fractures, previous surgery, autoimmune disease and impairment of the contralateral knee. The Lysholm scale, SF36 quality-of-life questionnaire and KT1000™ arthrometer were used. Results: After a mean follow-up of 18.1 months, there were no statistically significant differences between the groups regarding the Lysholm scale and KT1000™ measurements. However, the SF36 questionnaire showed a statistical difference such that transverse fixation was superior regarding pain and vitality. Conclusion: Both techniques were shown to be efficient for transfemoral fixation, but with almost no statistically significant difference between them. We believe that new studies will be necessary for better understanding of these differences. PMID:27042646

  12. Examination of rotational fixation of the femoral component in total hip arthroplasty. A mechanical study of micromovement and acoustic emission.

    PubMed

    Sugiyama, H; Whiteside, L A; Kaiser, A D

    1989-12-01

    Rotational loosening has recently emerged as an important cause of failure of the femoral component of total hip arthroplasties. This study was designed to investigate the role played by torsional loads in loosening of cementless femoral components and to evaluate three cementing techniques involving a combination of canal irrigation, manual insertion, and vacuum mixing combined with pressure injection of the cement for their ability to improve rotational fixation. Rotational micromotion and subsidence were measured in 24 preserved human anatomic specimen femora. Acoustic emission (AE) technique was applied as a non-destructive method for evaluating material failure during loading. From the micromovement data, torque to 50 mu subsidence and torque to failure were surprisingly low with cementless fixation and with poor cement technique but were markedly improved with pulsed irrigation. Further improvement was achieved by pressure injection and vacuum mixing of the cement. However, AE was detected even in the most carefully performed cement specimens under torsional-loading conditions commonly occurring in daily activities. These signs of microfailure of the cement mantle at relatively low torsional loads suggest that the mode of failure of deeply penetrated cement is by microfracture of the cement mantle. The poor performance suggests that cementless fixation of intramedullary stems provides unsatisfactory fixation against torsional loading. There is need for major improvements in fixation mechanisms and techniques. The signs of failure of the cement mantle at normally occurring torsional loads suggest that even the best cement technique is prone to failure in torsion when exposed to normal daily use. PMID:2582663

  13. Gaze shifts and fixations dominate gaze behavior of walking cats.

    PubMed

    Rivers, T J; Sirota, M G; Guttentag, A I; Ogorodnikov, D A; Shah, N A; Beloozerova, I N

    2014-09-01

    Vision is important for locomotion in complex environments. How it is used to guide stepping is not well understood. We used an eye search coil technique combined with an active marker-based head recording system to characterize the gaze patterns of cats walking over terrains of different complexity: (1) on a flat surface in the dark when no visual information was available, (2) on the flat surface in light when visual information was available but not required for successful walking, (3) along the highly structured but regular and familiar surface of a horizontal ladder, a task for which visual guidance of stepping was required, and (4) along a pathway cluttered with many small stones, an irregularly structured surface that was new each day. Three cats walked in a 2.5-m corridor, and 958 passages were analyzed. Gaze activity during the time when the gaze was directed at the walking surface was subdivided into four behaviors based on speed of gaze movement along the surface: gaze shift (fast movement), gaze fixation (no movement), constant gaze (movement at the body's speed), and slow gaze (the remainder). We found that gaze shifts and fixations dominated the cats' gaze behavior during all locomotor tasks, jointly occupying 62-84% of the time when the gaze was directed at the surface. As visual complexity of the surface and demand on visual guidance of stepping increased, cats spent more time looking at the surface, looked closer to them, and switched between gaze behaviors more often. During both visually guided locomotor tasks, gaze behaviors predominantly followed a repeated cycle of forward gaze shift followed by fixation. We call this behavior "gaze stepping". Each gaze shift took gaze to a site approximately 75-80cm in front of the cat, which the cat reached in 0.7-1.2s and 1.1-1.6 strides. Constant gaze occupied only 5-21% of the time cats spent looking at the walking surface.

  14. Gaze shifts and fixations dominate gaze behavior of walking cats.

    PubMed

    Rivers, T J; Sirota, M G; Guttentag, A I; Ogorodnikov, D A; Shah, N A; Beloozerova, I N

    2014-09-01

    Vision is important for locomotion in complex environments. How it is used to guide stepping is not well understood. We used an eye search coil technique combined with an active marker-based head recording system to characterize the gaze patterns of cats walking over terrains of different complexity: (1) on a flat surface in the dark when no visual information was available, (2) on the flat surface in light when visual information was available but not required for successful walking, (3) along the highly structured but regular and familiar surface of a horizontal ladder, a task for which visual guidance of stepping was required, and (4) along a pathway cluttered with many small stones, an irregularly structured surface that was new each day. Three cats walked in a 2.5-m corridor, and 958 passages were analyzed. Gaze activity during the time when the gaze was directed at the walking surface was subdivided into four behaviors based on speed of gaze movement along the surface: gaze shift (fast movement), gaze fixation (no movement), constant gaze (movement at the body's speed), and slow gaze (the remainder). We found that gaze shifts and fixations dominated the cats' gaze behavior during all locomotor tasks, jointly occupying 62-84% of the time when the gaze was directed at the surface. As visual complexity of the surface and demand on visual guidance of stepping increased, cats spent more time looking at the surface, looked closer to them, and switched between gaze behaviors more often. During both visually guided locomotor tasks, gaze behaviors predominantly followed a repeated cycle of forward gaze shift followed by fixation. We call this behavior "gaze stepping". Each gaze shift took gaze to a site approximately 75-80cm in front of the cat, which the cat reached in 0.7-1.2s and 1.1-1.6 strides. Constant gaze occupied only 5-21% of the time cats spent looking at the walking surface. PMID:24973656

  15. 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. PMID:27563602

  16. 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.

  17. Screening Prosopis (mesquite) germplasm for biomass production and nitrogen fixation

    SciTech Connect

    Felker, P.; Cannell, G.H.; Clark, P.R.; Osborn, J.F.

    1980-01-01

    The nitrogen-fixing trees of the genus Prosopis (mesquite or algaroba) are well adapted to the semi-arid and often saline regions of the world. These trees may produce firewood or pods for livestock food, they may stabilize sand dunes and they may enrich the soil by production of leaf litter supported by nitrogen fixation. A collection of nearly 500 Prosopis accessions representing North and South American and African germplasm has been established. Seventy of these accessions representing 14 taxa are being grown under field conditions where a 30-fold range in biomass productivity among accessions has been estimated. In a greehouse experiment, 13 Prosopis taxa grew on nitrogen-free medium nodulated, and had a 10-fold difference in nitrogen fixation (acetylene reduction). When Prosopis is propagated by seed the resulting trees are extremely variable in growth rate and presence or absence of thorns. Propagation of 6 Prosopis taxa by stem cuttings has been achieved with low success (1 to 10%) in field-grown plants and with higher success (50 to 100%) with young actively growing greenhouse plants.

  18. Diffusion tensor imaging of ex vivo cervical spinal cord specimens: the immediate and long term effects of fixation on diffusivity

    PubMed Central

    Kim, T. H.; Zollinger, L.; Shi, X. F.; Rose, J.; Jeong, E-K.

    2010-01-01

    Diffusion Tensor imaging (DTI) is an emerging noninvasive method for evaluating tissue microstructure, but is highly susceptible to in vivo motion artifact. Ex vivo experiments on fixed tissues are needed to improve DTI techniques, which require fixed tissue specimens. Several efforts have been made to study the effect of fixation on both human and mouse tissue, with varying results. Four human cervical cords and three segments of pig vivo cervical spinal cord specimens were imaged both before and after tissue fixation using 3D multi-shot diffusion weighted imaging (ms-DWEPI). Fixation caused a significant decrease in the longitudinal diffusivity while the relative anisotropy (RA), and radial diffusivity remained unaffected. Additionally, once adequately preserved the diffusivity parameters of fixed tissue remain constant over time. Fixation has important effects on the diffusivity of tissue specimens. These findings have important implications for the determination of tissue microstructure and function using DTI technologies. PMID:19051255

  19. 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)

  20. Fixational saccades during grating detection and discrimination.

    PubMed

    Spotorno, Sara; Masson, Guillaume S; Montagnini, Anna

    2016-01-01

    We investigated the patterns of fixational saccades in human observers performing two classical perceptual tasks: grating detection and discrimination. First, participants were asked to detect a vertical or tilted grating with one of three spatial frequencies and one of four luminance contrast levels. In the second experiment, participants had to discriminate the spatial frequency of two supra-threshold gratings. The gratings were always embedded in additive, high- or low-contrast pink noise. We observed that the patterns of fixational saccades were highly idiosyncratic among participants. Moreover, during the grating detection task, the amplitude and the number of saccades were inversely correlated with stimulus visibility. We did not find a systematic relationship between saccade parameters and grating frequency, apart from a slight decrease of saccade amplitude during grating discrimination with higher spatial frequencies. No consistent changes in the number and amplitude of fixational saccades with performance accuracy were reported. Surprisingly, during grating detection, saccade number and amplitude were similar in grating-with-noise and noise-only displays. Grating orientation did not affect substantially saccade direction in either task. The results challenge the idea that, when analyzing low-level spatial properties of visual stimuli, fixational saccades can be adapted in order to extract task-relevant information optimally. Rather, saccadic patterns seem to be overall modulated by task context, stimulus visibility and individual variability.

  1. 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.

  2. Acuity, crowding, reading and fixation stability.

    PubMed

    Falkenberg, Helle K; Rubin, Gary S; Bex, Peter J

    2007-01-01

    People with age-related macular disease frequently experience reading difficulty that could be attributed to poor acuity, elevated crowding or unstable fixation associated with peripheral visual field dependence. We examine how the size, location, spacing and instability of retinal images affect the visibility of letters and words at different eccentricities. Fixation instability was simulated in normally sighted observers by randomly jittering single or crowded letters or words along a circular arc of fixed eccentricity. Visual performance was assessed at different levels of instability with forced choice measurements of acuity, crowding and reading speed in a rapid serial visual presentation paradigm. In the periphery: (1) acuity declined; (2) crowding increased for acuity- and eccentricity-corrected targets; and (3), the rate of reading fell with acuity-, crowding- and eccentricity-corrected targets. Acuity and crowding were unaffected by even high levels of image instability. However, reading speed decreased with image instability, even though the visibility of the component letters was unaffected. The results show that reading performance cannot be standardised across the visual field by correcting the size, spacing and eccentricity of letters or words. The results suggest that unstable fixation may contribute to reading difficulties in people with low vision and therefore that rehabilitation may benefit from fixation training.

  3. Behind the discovery of "Nissenbaum's fixative".

    PubMed

    Nissenbaum, G

    2001-01-01

    The author describes the serendipitous discovery, conception, development, and history of Nissenbaum's Fixative while an undergraduate biology major in the early 1950s. The subsequent uses, applications, and modifications over the past forty-seven years are also described. Some of the modifications omitted from his short original paper are mentioned. Highlights of his subsequent career in the field of medicine are noted.

  4. A Complication of Posterior Malleolar Fracture Fixation.

    PubMed

    Patel, Ankit; Charles, Loren; Ritchie, James

    2016-01-01

    We present a case of tibial nerve impingement by an anteroposterior screw inserted for stabilization of a posterior malleolar fracture. This specific complication has not previously been described in published studies, although numerous reports have described various forms of peripheral nerve entrapment. We discuss the merits of fixation of these fractures using a posterolateral approach.

  5. 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

  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 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...

  8. 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...

  9. 21 CFR 888.3010 - Bone fixation cerclage.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 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, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 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 888.3010 - Bone fixation cerclage.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 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...

  12. 21 CFR 868.5770 - Tracheal tube fixation device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Tracheal tube fixation device. 868.5770 Section... (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...

  13. 21 CFR 868.5770 - Tracheal tube fixation device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Tracheal tube fixation device. 868.5770 Section... (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...

  14. 21 CFR 868.5770 - Tracheal tube fixation device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Tracheal tube fixation device. 868.5770 Section... (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...

  15. 21 CFR 868.5770 - Tracheal tube fixation device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tracheal tube fixation device. 868.5770 Section... (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...

  16. 21 CFR 868.5770 - Tracheal tube fixation device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Tracheal tube fixation device. 868.5770 Section... (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...

  17. Effectiveness of interference screw fixation in ulnar collateral ligament reconstruction.

    PubMed

    Nissen, Carl W

    2008-07-01

    Ulnar collateral ligament disruptions of the elbow are increasingly common for athletes involved in overhead sports. One newer reconstructive technique combines the use of a biotenodesis screw for ulnar fixation with the docking procedure for humeral fixation referred to as the DANE procedure. Biomechanical evaluations have determined that the combined procedure has properties similar to previous methods, but few comparative clinical studies have been performed. The current study compares the DANE procedure to a traditional method of ulnar collateral ligament reconstruction with a medium range follow-up. Twelve ulnar collateral ligament reconstructions were observed for a minimum of 21 months. Six reconstructions were performed using bone tunnels on the ulna. The other 6 used a biotenodesis interference screw on the ulna. Both groups used the docking procedure on the humerus. Identical rehabilitation phases were followed by both groups. Attention was paid not only to the time to return to play and the level able to be returned to but also to interoperative differences, including tourniquet time. We concluded that the DANE reconstruction is an appropriate and effective method. Results are similar to those achieved with a traditional reconstructive method. The study also demonstrates that tourniquet time and, therefore, operative time is less for the DANE procedure.

  18. An external fixation method and device to study fracture healing in rats.

    PubMed

    Mark, Hans; Bergholm, Jan; Nilsson, Anders; Rydevik, Björn; Strömberg, Lennart

    2003-08-01

    We wished to establish a reproducible model for fracture fixation to be used in fracture healing research and therefore developed an external fixation construct and surgical procedure adapted to Sprague-Dawley rats. We evaluated the mechanical properties of the construct in brass rods and rat bone, in an Instron test machine with axial and transverse loading, and the in vivo performance. We found that the mechanical properties of the construct in brass rods were predictable and could be repeated in rat femora. In all tests, the axial load was about 10 times the transverse for the same degree of deformation. The stiffness among fixators was uniform. 1 mm pins caused about 50% less stiffness than 1.2 mm pins in axial loading of rat bone (p < 0.001) and brass rods (p < 0.001) as well as in transverse loading of brass rods (p < 0.001). Loosening of 1 or 2 screws that lock the pins to the fixator reduced stiffness by about 50% in axial loading of rat bone (p = 0.009) and brass rods (p = 0.05). A change in the distance between the bone surface and the fixator was linearly related to the stiffness in axial loading of rat bone (p < 0.001) and brass rods (p < 0.001) and in transverse loading of brass rods (p < 0.001). If the bone ends touched each other, the axial stiffness of the construct increased almost 10 times (265 N/mm), as compared to a fracture gap size of 2 mm (31 N/mm). In vivo experiments had a complication rate of less than 10% when we used 1.2 mm pins, 6 mm offset and rats weighing 350-450 g. Our method and device for experimental external fixation of rat femora are reliable and the findings are reproducible. These can be used in bone repair and fracture healing research. PMID:14521302

  19. Femoral Aperture Fixation Improves Anterior Cruciate Ligament Graft Function When Added to Cortical Suspensory Fixation

    PubMed Central

    Porter, Mark D.; Shadbolt, Bruce

    2016-01-01

    Background: Recommendations for bone tunnel placement during anterior cruciate ligament (ACL) reconstruction have become more precise. However, these recommendations differ neither with the choice of graft nor with the method of fixation used. The influence of the method of femoral fixation used on the biomechanical function of a soft tissue ACL graft remains unknown. Hypothesis: Our null hypothesis was that adding femoral aperture fixation to femoral cortical fixation, using the same bone tunnels, will not alter the control of anterior translation (AT) and internal rotation (IR) during ACL reconstruction using a hamstring graft. Study Design: Controlled laboratory study. Methods: A total of 22 patients with an acute isolated ACL rupture underwent reconstruction using a single-bundle autologous hamstring graft. Computer navigation was used intraoperatively to plot the AT and IR during the pivot-shift test before reconstruction, after ACL reconstruction using cortical suspensory fixation, and after the addition of femoral aperture fixation. Statistical analysis (analysis of variance) was used to compare the AT and IR during the pivot shift at each stage in the procedure. Results: Before ACL reconstruction, the mean (±SD) AT was 14.2 ± 7.3 mm and mean IR was 17.2° ± 5.5°. After reconstruction using femoral cortical suspension, these figures were significantly reduced to 6.2 ± 3.5 mm and 12.5° ± 3.20°, respectively (P < .001). The addition of the aperture fixation was associated with a further significant reduction to 4.6 ± 3.2 mm and 10.4° ± 2.7°, respectively (P < .001). Conclusion: The addition of femoral aperture fixation to suspensory fixation results in a significant reduction in both the AT and IR that occurs during the pivot-shift assessment immediately after ACL reconstruction using autologous hamstring graft. Clinical Relevance: The most precise positioning of bone tunnels during soft tissue ACL reconstruction needs to take into consideration

  20. Femoral Aperture Fixation Improves Anterior Cruciate Ligament Graft Function When Added to Cortical Suspensory Fixation

    PubMed Central

    Porter, Mark D.; Shadbolt, Bruce

    2016-01-01

    Background: Recommendations for bone tunnel placement during anterior cruciate ligament (ACL) reconstruction have become more precise. However, these recommendations differ neither with the choice of graft nor with the method of fixation used. The influence of the method of femoral fixation used on the biomechanical function of a soft tissue ACL graft remains unknown. Hypothesis: Our null hypothesis was that adding femoral aperture fixation to femoral cortical fixation, using the same bone tunnels, will not alter the control of anterior translation (AT) and internal rotation (IR) during ACL reconstruction using a hamstring graft. Study Design: Controlled laboratory study. Methods: A total of 22 patients with an acute isolated ACL rupture underwent reconstruction using a single-bundle autologous hamstring graft. Computer navigation was used intraoperatively to plot the AT and IR during the pivot-shift test before reconstruction, after ACL reconstruction using cortical suspensory fixation, and after the addition of femoral aperture fixation. Statistical analysis (analysis of variance) was used to compare the AT and IR during the pivot shift at each stage in the procedure. Results: Before ACL reconstruction, the mean (±SD) AT was 14.2 ± 7.3 mm and mean IR was 17.2° ± 5.5°. After reconstruction using femoral cortical suspension, these figures were significantly reduced to 6.2 ± 3.5 mm and 12.5° ± 3.20°, respectively (P < .001). The addition of the aperture fixation was associated with a further significant reduction to 4.6 ± 3.2 mm and 10.4° ± 2.7°, respectively (P < .001). Conclusion: The addition of femoral aperture fixation to suspensory fixation results in a significant reduction in both the AT and IR that occurs during the pivot-shift assessment immediately after ACL reconstruction using autologous hamstring graft. Clinical Relevance: The most precise positioning of bone tunnels during soft tissue ACL reconstruction needs to take into consideration

  1. Right visual field advantage in parafoveal processing: evidence from eye-fixation-related potentials.

    PubMed

    Simola, Jaana; Holmqvist, Kenneth; Lindgren, Magnus

    2009-11-01

    Readers acquire information outside the current eye fixation. Previous research indicates that having only the fixated word available slows reading, but when the next word is visible, reading is almost as fast as when the whole line is seen. Parafoveal-on-foveal effects are interpreted to reflect that the characteristics of a parafoveal word can influence fixation on a current word. Prior studies also show that words presented to the right visual field (RVF) are processed faster and more accurately than words in the left visual field (LVF). This asymmetry results either from an attentional bias, reading direction, or the cerebral asymmetry of language processing. We used eye-fixation-related potentials (EFRP), a technique that combines eye-tracking and electroencephalography, to investigate visual field differences in parafoveal-on-foveal effects. After a central fixation, a prime word appeared in the middle of the screen together with a parafoveal target that was presented either to the LVF or to the RVF. Both hemifield presentations included three semantic conditions: the words were either semantically associated, non-associated, or the target was a non-word. The participants began reading from the prime and then made a saccade towards the target, subsequently they judged the semantic association. Between 200 and 280ms from the fixation onset, an occipital P2 EFRP-component differentiated between parafoveal word and non-word stimuli when the parafoveal word appeared in the RVF. The results suggest that the extraction of parafoveal information is affected by attention, which is oriented as a function of reading direction.

  2. Posterior Wall Blowout During Anterior Cruciate Ligament Reconstruction: Suspensory Cortical Fixation With a Screw and Washer Post.

    PubMed

    Mitchell, Justin J; Chahla, Jorge; Dean, Chase S; Menge, Travis J; Vap, Alexander R; Cram, Tyler R; LaPrade, Robert F

    2016-06-01

    Posterior wall blowout can be a devastating intraoperative complication in anterior cruciate ligament reconstruction. This loss of osseous containment can cause difficulty with graft fixation and can potentially lead to early graft failure if unrecognized and left untreated. If cortical blowout occurs despite careful planning and proper surgical technique, a thorough knowledge of the local anatomy and surgical salvage options is paramount to ensure positive patient outcomes. This article highlights our preferred salvage technique using suspensory cortical fixation with a screw and washer construct. PMID:27656377

  3. Combining of small fragment screws and large fragment plates for open reduction and internal fixation of periprosthetic humeral fractures

    PubMed Central

    Seybold, Dominik; Citak, Mustafa; Königshausen, Matthias; Gessmann, Jan; Schildhauer, Thomas A.

    2011-01-01

    Operative treatment of periprosthetic humeral fractures in elderly patients with osteoporotic bone requires a stable fixations technique. The combination of 3.5 cortical screws with washers in a 4.5 Arbeitsgemeinschaft für Osteosynthesefragen, Limited-contact dynamic compression plate or Locking plate, allows a stable periprosthetic fixation with the small 3.5 screws and 4.5 screws above and below the prosthesis, respectively. This combination is a cost-effective technique to treat periprosthetic humeral fractures. PMID:22223961

  4. Fixation-coexistence transition in spatial populations

    NASA Astrophysics Data System (ADS)

    Dall'Asta, Luca; Caccioli, Fabio; Beghè, Deborah

    2013-01-01

    Balancing selection is a special case of frequency-dependent selection that is known to be the major force for the maintenance of biodiversity and polymorphism in natural populations. In finite populations, genetic drift eventually drives the population to fixation to the detriment of biodiversity. The interplay between selection and genetic drift is much richer in spatially extended populations, where the local density of individuals can be low even in the limit of infinitely large systems. We consider the limit of low local density of individuals (strong genetic drift) that is well represented by a modified voter model. We show analytically the existence of a non-equilibrium phase transition between a region in which fixation always occurs and a coexistence phase for a one-dimensional system. We also provide a characterization of the dynamical properties of the system, in particular for what concerns the coarsening behavior and the speed of propagation of heterozygosity above the threshold.

  5. MR imaging and cervical fixation devices: evaluation of ferromagnetism, heating, and artifacts at 1.5 Tesla.

    PubMed

    Shellock, F G

    1996-01-01

    The purpose of this study was to assess ferromagnetism, heating, and artifacts for cervical fixation devices exposed to a 1.5 T MR system. Cervical fixation devices (three halos, one tong and two halo vests) were evaluated for compatibility with MR procedures. Ferromagnetism was determined using a previously described technique. Heating was evaluated by measuring temperatures at various positions on the cervical fixation devices while applied to a volunteer subject before and during the use of various pulse sequences, including an magnetization transfer contrast (MTC) sequence. Artifacts associated with routine clinical MR imaging of the cervical spine were qualitatively evaluated with the cervical fixation devices applied to a volunteer subject. None of the devices displayed attraction to the magnetic field. The temperature changes were +/-1.5 degrees C in each instance. The MTC pulse sequence produced a sensation of "heating" the skull pins that may have been caused by vibration of the cervical fixation device. The MR images of the cervical spine were obtained without apparent artifacts using each routine, clinical pulse sequence. The lack of ferromagnetism, negligible heating, and capability of obtaining diagnostically acceptable studies of the cervical spine indicate that MR imaging performed at 1.5 T or less may be conducted safely in patients with each of the cervical fixation devices tested using conventional pulse sequences. PMID:9071001

  6. Reading with a filtered fovea: the influence of visual quality at the point of fixation during reading.

    PubMed

    Jordan, Timothy R; McGowan, Victoria A; Paterson, Kevin B

    2012-12-01

    Reading relies critically on processing text in foveal vision during brief fixational pauses, and high-quality visual input from foveal text is fundamental to theories of reading. However, the quality of visual input from foveal text that is actually functional for reading and the effects of this input on reading performance are unclear. To investigate these issues, a moving, gaze-contingent foveal filtering technique was developed to display areas of text within foveal vision that provided only coarse, medium, or fine scale visual input during each fixational pause during reading. Normal reading times were unaffected when foveal text up to three characters wide at the point of fixation provided any one visual input (coarse, medium, or fine). Wider areas of coarse visual input lengthened reading times, but reading still occurred, and normal reading times were completely unaffected when only medium or fine visual input extended across the entire fovea. Further analyses revealed that each visual input had no effect on the number of fixations made when normal text was read, that adjusting fixation durations helped preserve reading efficiency for different visual inputs, and that each visual input had virtually no effect on normal saccades. These findings indicate that, despite the resolving power of foveal vision and the emphasis placed on high-quality foveal visual input by theories of reading, normal reading functions with similar success using a range of restricted visual inputs from foveal text, even at the point of fixation. Some implications of these findings for theories of reading are discussed.

  7. The Stability of Human Eye Orientation During Visual Fixation

    NASA Technical Reports Server (NTRS)

    Ott, Dietmar; Seidman, Scott H.; Leigh, R. John

    1992-01-01

    Using the magnetic search coil technique, gaze stability in the horizontal, vertical and torsional planes was measured binocularly in human subjects during visual fixation. Horizontal and vertical eye rotations exhibited a mixture of slow drifts and resetting microsaccades yielding an average standard deviation of 0.11 and 0.10 deg. respectively. In contrast, torsional rotations showed unsystematic smooth drifts with fewer saccades yielding an average standard deviation of 0.18 deg. The lower precision of gaze control in the torsional plane may reflect (1) a discrepancy between the encoding of retinal images in two dimensions but of ocular motor control signals in three dimensions, and (2) the visual consequences of ocular drifts in the torsional plane, which differ from those in the horizontal and vertical planes.

  8. "False" migration of rigid fixation appliances in pediatric craniofacial surgery.

    PubMed

    Papay, F A; Hardy, S; Morales, L; Walker, M; Enlow, D

    1995-07-01

    Osseous fixation techniques have been widely used to provide rigid stabilization in the craniofacial skeleton. Reported sequelae of its usage has been limited to palpation of the screw-plate system and radiological imaging artifacts. Over the past 3 years we have identified miniplates, microplates, and wire sutures on the inner cranial table of the growing child. The observation of "false" migration of these appliances has provided the impetus to review these patients in more detail. Twenty patients underwent secondary cranial remodeling within a two-year period; 7 of these patients were seen to have "false" migration. There were no untoward sequelae in removal of these appliances, and no adverse neurological symptoms were seen.

  9. Fracture biology, biomechanics, and internal fixation.

    PubMed

    Trostle, S S; Markel, M D

    1996-03-01

    The success of orthopedic surgery in ruminants is directly related to the surgeon's knowledge and understanding of bone physiology and mechanics. The relationship of the macro and micro structure and function of bone as it relates to fracture physiology and repair is discussed. A basic review of the biomechanical principles of bone, bone fracture, and fracture repair are presented. The clinical and biomechanical principles of internal fixation are described for fracture repair in ruminants.

  10. Advantages and disadvantages of pinless external fixation.

    PubMed

    Thomas, S R; Giele, H; Simpson, A H

    2000-12-01

    The AO pinless external fixator (PEF) uses trocar tipped clamps to grip the outer tibial cortex rather than pins to transfix it. Its main advantage is to avoid further contamination of the medullary canal in open tibial fractures where a nail may subsequently be used. We tested the anatomical safety of this device and its effect on plastic surgical procedures compared with a standard unilateral external fixator (UEF).The PEF and UEF were placed on two amputated limbs which were then dissected. Structures at risk were traced on ten cadaver limbs. We found that important anatomical structures were endangered by the PEF and that safe zones could not always be defined. The UEF avoided these structures. Plastic surgical approaches were made more difficult by the PEF which imposed limitations on local flap design and endangered the arterial perforators which supply them. We conclude that safety is compromised by the PEF because margins for error are small. It poses additional problems in soft tissue reconstruction and highlights the need for co-operation between plastic surgical and orthopaedic teams in choice of fixation device.

  11. Operational momentum affects eye fixation behaviour.

    PubMed

    Klein, E; Huber, S; Nuerk, H C; Moeller, K

    2014-01-01

    The operational momentum effect (OM) indicates an association of mental addition with a rightward spatial bias, whereas subtraction is associated with a leftward bias. To evaluate the assumed attentional origin of the OM effect, we evaluated not only participants' relative estimation error in a task requiring them to locate addition and subtraction results on a given number line but also their eye-fixation behaviour. Furthermore, to investigate the situatedness of spatial-numerical associations, the orientation of the number line (left-to-right vs. right-to left) was manipulated. OM biases in participants' explicit number line estimations and more implicit eye-fixation behaviour are integrated into a two-process hypothesis of the OM effect suggesting a first rough spatial anticipation followed by an evaluation/correction process. This account not only is capable of accounting for the results observed for participants' relative estimation error but is also corroborated by the eye-fixation results. Importantly, the fact that all effects were found independent of the orientation of the number line indicates that spatial-numerical associations such as the OM effect may not be hard-wired associations of spatial and numerical representations but rather reflect influences of situatedness on numerical cognition. PMID:24716442

  12. Integrated effect of stimulation at fixation points on EFRP (eye-fixation related brain potentials).

    PubMed

    Kazai, K; Yagi, A

    1999-06-01

    The purpose of this study was to investigate the integrated effect of stimulation at the fixation points just before and just after saccadic eye-movement (saccade) on eye-fixation related brain potentials (EFRP: P75 and N105). Checkerboard patterns were used as stimuli. In Experiment 1, changes in check sizes between two fixation points enhanced the amplitude of P75, while changes in the phases of patterns between the two points did not affect EFRP. This result showed that EFRP was affected by two fixation points, and that changes in the retinal image between the two points did not necessarily affect EFRP. In Experiment 2, the relationship between EFRP and check size was investigated in detail. A second order relationship between logarithm of check size and the latency of P75, and a linear relationship between logarithm of check size and the amplitude of N105 were found. The effect of check size on the amplitude of P75 which might explain the increased amplitude of P75 observed in Experiment 1 did not appear. These results suggest that EFRP might reflect relative higher processing than peripheral stimulation at one fixation point.

  13. Distinguishing between target and nontarget fixations in a visual search task using fixation-related potentials.

    PubMed

    Brouwer, Anne-Marie; Reuderink, Boris; Vincent, Joris; van Gerven, Marcel A J; van Erp, Jan B F

    2013-01-01

    The P300 event-related potential (ERP) can be used to infer whether an observer is looking at a target or not. Common practice in P300 experiments and applications is that observers are asked to fixate their eyes while stimuli are presented. We investigated the possibility to differentiate between single target and nontarget fixations in a target search task involving eye movements by using EEG epochs synchronized to fixation onset (fixation-related potentials: FRPs). Participants systematically scanned search displays consisting of six small Landolt Cs in search of Cs with a particular orientation. After each search display, they indicated whether and where target Cs had been presented. As expected, an FRP component consistent with the P300 reliably distinguished between target and nontarget fixations. It was possible to classify single FRPs into target and nontarget FRPs above chance (on average 62% correct, where 50% would be chance). These results are the first step to practical applications such as covertly monitoring observers' interests and supporting search tasks.

  14. Evaluation of 3 Fixation Devices for Tibial-Sided Anterior Cruciate Ligament Graft Backup Fixation.

    PubMed

    Verioti, Christopher A; Sardelli, Matthew C; Nguyen, Tony

    2015-07-01

    We conducted a study to biomechanically evaluate 3 methods of tibial-sided fixation for anterior cruciate ligament reconstruction: fully threaded interference screw only, interference screw backed with 4.75-mm SwiveLock anchor, and fully threaded bio-interference screw backed with 4.5-mm bicortical screw (all Arthrex). Thirty skeletally mature porcine tibiae were used. The first group was prepared by graft fixation within the tibial tunnel using only an interference screw. The second and third groups included an interference screw with 2 types of secondary fixation: 4.5-mm bicortical post and SwiveLock anchor. Mechanical testing consisted of 500 cycles between 50 and 250 N at 1 Hz, followed by a pull to failure conducted at 20 mm per minute. Ultimate load-to-failure testing demonstrated the largest mean (SD) load tolerated in the post/washer group, 1148 (186) N, versus the SwiveLock group, 1007 (176) N, and the screw-only group, 778 (139) N. There was no statistical difference between the 2 backup fixation groups. Use of a SwiveLock anchor as backup fixation at the tibial side in soft-tissue anterior cruciate ligament reconstruction is a safe, effective alternative to a bicortical post and provides statistically equivalent pullout strength with unlikely requirement for future hardware removal.

  15. 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

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

    PubMed

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

    2015-12-11

    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.

  17. Fixational instability and natural image statistics: implications for early visual representations.

    PubMed

    Rucci, Michele; Casile, Antonino

    2005-01-01

    Under natural viewing conditions, small movements of the eye, head and body prevent the maintenance of a steady direction of gaze. It is known that stimuli tend to fade when they are stabilized on the retina for several seconds. However, it is unclear whether the physiological motion of the retinal image serves a visual purpose during the brief periods of natural visual fixation. This study examines the impact of fixational instability on the statistics of the visual input to the retina and on the structure of neural activity in the early visual system. We show that fixational instability introduces a component in the retinal input signals that, in the presence of natural images, lacks spatial correlations. This component strongly influences neural activity in a model of the LGN. It decorrelates cell responses even if the contrast sensitivity functions of simulated cells are not perfectly tuned to counter-balance the power-law spectrum of natural images. A decorrelation of neural activity at the early stages of the visual system has been proposed to be beneficial for discarding statistical redundancies in the input signals. The results of this study suggest that fixational instability might contribute to the establishment of efficient representations of natural stimuli.

  18. Ultrasound Biomicroscopy Comparison of Ab Interno and Ab Externo Intraocular Lens Scleral Fixation.

    PubMed

    Horiguchi, Lie; Garcia, Patricia Novita; Malavazzi, Gustavo Ricci; Allemann, Norma; Gomes, Rachel L R

    2016-01-01

    Purpose. To compare ab interno and ab externo scleral fixation of posterior chamber intraocular lenses (PCIOL) using ultrasound biomicroscopy (UBM). Methods. Randomized patients underwent ab externo or ab interno scleral fixation of a PCIOL. Ultrasound biomicroscopy was performed 3 to 6 months postoperatively, to determine PCIOL centration, IOL distance to the iris at 12, 3, 6, and 9 hours, and haptics placement in relation to the ciliary sulcus. Results. Fifteen patients were enrolled in the study. The ab externo technique was used in 7 eyes (46.6%) and the ab interno in 8 eyes (53.3%). In the ab externo technique, 14 haptics were located: 4 (28.57%) in the ciliary sulcus; 2 (14.28%) anterior to the sulcus; and 8 (57.14%) posterior to the sulcus, 6 in the ciliary body and 2 posterior to the ciliary body. In the ab interno group, 4 haptics (25.0%) were in the ciliary sulcus, 2 (12.50%) anterior to the sulcus, and 10 (75.0%) posterior to the sulcus, 4 in the ciliary body and 6 posterior to the ciliary body. Conclusions. Ab externo and ab interno scleral fixation techniques presented similar results in haptic placement. Ab externo technique presented higher vertical tilt when compared to the ab interno.

  19. Ultrasound Biomicroscopy Comparison of Ab Interno and Ab Externo Intraocular Lens Scleral Fixation

    PubMed Central

    Horiguchi, Lie; Garcia, Patricia Novita; Malavazzi, Gustavo Ricci; Allemann, Norma

    2016-01-01

    Purpose. To compare ab interno and ab externo scleral fixation of posterior chamber intraocular lenses (PCIOL) using ultrasound biomicroscopy (UBM). Methods. Randomized patients underwent ab externo or ab interno scleral fixation of a PCIOL. Ultrasound biomicroscopy was performed 3 to 6 months postoperatively, to determine PCIOL centration, IOL distance to the iris at 12, 3, 6, and 9 hours, and haptics placement in relation to the ciliary sulcus. Results. Fifteen patients were enrolled in the study. The ab externo technique was used in 7 eyes (46.6%) and the ab interno in 8 eyes (53.3%). In the ab externo technique, 14 haptics were located: 4 (28.57%) in the ciliary sulcus; 2 (14.28%) anterior to the sulcus; and 8 (57.14%) posterior to the sulcus, 6 in the ciliary body and 2 posterior to the ciliary body. In the ab interno group, 4 haptics (25.0%) were in the ciliary sulcus, 2 (12.50%) anterior to the sulcus, and 10 (75.0%) posterior to the sulcus, 4 in the ciliary body and 6 posterior to the ciliary body. Conclusions. Ab externo and ab interno scleral fixation techniques presented similar results in haptic placement. Ab externo technique presented higher vertical tilt when compared to the ab interno. PMID:27293878

  20. 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

  1. Ab-interno scleral suture loop fixation with cow-hitch knot in posterior chamber intraocular lens decentration

    PubMed Central

    Can, Ertuğrul; Koçak, Nurullah; Yücel, Özlem Eşki; Gül, Adem; Öztürk, Hilal Eser; Sayın, Osman

    2016-01-01

    Aim of Study: To describe a simplified ab-interno cow-hitch suture fixation technique for repositioning decentered posterior chamber intraocular lens (PC IOL). Materials and Methods: Two cases are presented with the surgical correction of decentered and subluxated IOL. Ab-interno scleral suture fixation technique with hitch-cow knot in the eye was performed with a ciliary sulcus guide instrument and 1 year follow-up was completed. Results: Both of the patients had well centered lenses postoperatively. Corrected distant and near visual acuities of the patients were improved. There was no significant postoperative complication. In the follow-up period of 1 year, no evidence of suture erosion was found. Conclusions: Ab-interno scleral suture loop fixation with hitch-cow knot in the eye was effective in repositioning decentered or subluxated PC IOLs with excellent postoperative centered lenses and visual outcomes. PMID:27050346

  2. [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

  3. Weigners fixative-an alternative to formalin fixation for histology with improved preservation of nucleic acids.

    PubMed

    Klopfleisch, R; von Deetzen, M; Weiss, A Th; Weigner, J; Weigner, F; Plendl, J; Gruber, A D

    2013-01-01

    Formalin fixation and paraffin embedding (FFPE) is the standard method for tissue storage in histopathology. However, FFPE has disadvantages in terms of user health, environment, and nucleic acid integrity. Weigners fixative has been suggested as an alternative for embalming cadavers in human and veterinary anatomy. The present study tested the applicability of Weigners for histology and immunohistochemistry and the preservation of nucleic acids. To this end, a set of organs was fixed for 2 days and up to 6 months in Weigners (WFPE) or formalin. WFPE tissues from the skin, brain, lymphatic tissues, liver, and muscle had good morphologic preservation, comparable to formalin fixation. The quality of kidney and lung samples was inferior to FFPE material due to less accentuated nuclear staining and retention of proteinaceous interstitial fluids. Azan, Turnbull blue, toluidin, and immunohistochemical stainings for CD79a, cytokeratin, vimentin, and von Willebrand factor led to comparable results with both fixates. Of note, immunohistochemical detection of CD3 was possible after 6 months in WFPE but not in FFPE tissues. mRNA, miRNA, and DNA from WFPE tissues had superior quality and allowed for amplification of miRNA, 400-bp-long mRNA, and 1000-bp-long DNA fragments after 6 months of fixation in WFPE. In summary, Weigners fixative is a nonhazardous alternative to formalin, which provides a good morphologic preservation of most organs, a similar sensitivity for protein detection, and a superior preservation of nucleic acids. Weigners may therefore be a promising alternative to cryopreservation and may be embraced by people affected by formalin allergies.

  4. Fast and asymptotic computation of the fixation probability for Moran processes on graphs.

    PubMed

    Alcalde Cuesta, F; González Sequeiros, P; Lozano Rojo, Á

    2015-03-01

    Evolutionary dynamics has been classically studied for homogeneous populations, but now there is a growing interest in the non-homogeneous case. One of the most important models has been proposed in Lieberman et al. (2005), adapting to a weighted directed graph the process described in Moran (1958). The Markov chain associated with the graph can be modified by erasing all non-trivial loops in its state space, obtaining the so-called Embedded Markov chain (EMC). The fixation probability remains unchanged, but the expected time to absorption (fixation or extinction) is reduced. In this paper, we shall use this idea to compute asymptotically the average fixation probability for complete bipartite graphs K(n,m). To this end, we firstly review some recent results on evolutionary dynamics on graphs trying to clarify some points. We also revisit the 'Star Theorem' proved in Lieberman et al. (2005) for the star graphs K(1,m). Theoretically, EMC techniques allow fast computation of the fixation probability, but in practice this is not always true. Thus, in the last part of the paper, we compare this algorithm with the standard Monte Carlo method for some kind of complex networks.

  5. Transscleral fixation of closed loop haptic acrylic posterior chamber intraocular lens in aphakic nonvitrectomized eyes

    PubMed Central

    Agrawal, Siddharth; Singh, Vinita; Gupta, Sanjiv Kumar; Misra, Nibha; Srivastava, Rajat M

    2015-01-01

    Purpose: To evaluate the outcome of transscleral fixation of closed loop haptic acrylic posterior chamber intraocular lens (PCIOL) in aphakia in nonvitrectomized eyes. Materials and Methods: Patients with postcataract surgery aphakia, trauma with posterior capsule injury, subluxated crystalline lens, and per operative complications where sulcus implantation was not possible were included over a 1-year period. Scleral fixation of acrylic hydrophilic PCIOL was performed according to the described technique, and the patients were evaluated on the day 1, 3, 14, and at 3 and 12 months postoperatively for IOL centration, pseudophakodonesis, change in best-corrected visual acuity (BCVA), and any other complications. Results: Out of twenty-nine eyes of 24 patients, who completed the study, 25 (86.2%) eyes had improved, 2 (6.9%) eyes showed no change, and 2 (6.9%) eyes had worsening of BCVA. Three (10.3%) eyes developed postoperative complications. A significant improvement in mean BCVA (P < 0.0001) was observed after the procedure. Mean duration of follow-up was 26.2 months (range 22–35 months). Conclusion: The use of closed loop haptic acrylic IOL for scleral fixation appears to be safe and effective alternative to conventional scleral fixated polymethyl methacrylate intraocular lenses. PMID:26576522

  6. Fast and asymptotic computation of the fixation probability for Moran processes on graphs.

    PubMed

    Alcalde Cuesta, F; González Sequeiros, P; Lozano Rojo, Á

    2015-03-01

    Evolutionary dynamics has been classically studied for homogeneous populations, but now there is a growing interest in the non-homogeneous case. One of the most important models has been proposed in Lieberman et al. (2005), adapting to a weighted directed graph the process described in Moran (1958). The Markov chain associated with the graph can be modified by erasing all non-trivial loops in its state space, obtaining the so-called Embedded Markov chain (EMC). The fixation probability remains unchanged, but the expected time to absorption (fixation or extinction) is reduced. In this paper, we shall use this idea to compute asymptotically the average fixation probability for complete bipartite graphs K(n,m). To this end, we firstly review some recent results on evolutionary dynamics on graphs trying to clarify some points. We also revisit the 'Star Theorem' proved in Lieberman et al. (2005) for the star graphs K(1,m). Theoretically, EMC techniques allow fast computation of the fixation probability, but in practice this is not always true. Thus, in the last part of the paper, we compare this algorithm with the standard Monte Carlo method for some kind of complex networks. PMID:25625871

  7. Retrograde intramedullary fixation of long bone fractures through ipsilateral traumatic amputation sites.

    PubMed

    Wagner, Scott C; Chi, Benjamin B; Gordon, Wade T; Potter, Benjamin K

    2015-06-01

    The technique of retrograde intramedullary fixation of fractures through open traumatic amputations has not been previously described. We performed a retrospective case series at a tertiary-care military hospital setting. Ten patients met inclusion criteria. All were male, and all were injured through improvised explosive device. Outcome measures included the incidence of fracture nonunion, osteomyelitis or acute infection, heterotopic ossification (HO), as well as successful prosthesis fitting and ambulation. Average time to fixation after injury and amputation closure was 11.7 and 12.2 days, respectively. Follow-up averaged 20.2 months. The radiographic union rate was 100%, and time to osseous union averaged 7.5 months. One patient had an amputation site infection requiring revision, but none of the nails was removed for infectious reasons. HO occurred in 7 patients, and 2 patients required revision for symptomatic HO. All patients were successfully fitted with prostheses and able to ambulate. To our knowledge, this is the only series in the literature to specifically describe retrograde intramedullary fixation of long bone fractures through the zone of traumatic amputation sites. The infectious risk is relatively low, whereas the union rate (100%) and successful prosthesis fitting are high. For patients with similar injuries, retrograde intramedullary fixation through the zone of amputation is a viable treatment option.

  8. Glutaraldehyde fixation preserves the trend of elasticity alterations for endothelial cells exposed to TNF-α.

    PubMed

    Targosz-Korecka, Marta; Brzezinka, Grzegorz Daniel; Danilkiewicz, Joanna; Rajfur, Zenon; Szymonski, Marek

    2015-03-01

    Among the users of atomic force microscopy based techniques, there is an ongoing discussion, whether cell elasticity measurements performed on fixed cells could be used for determination of the relative elasticity changes of the native (unfixed) cells subjected to physiologically active external agents. In this article, we present a case, for which the legitimacy of cell fixation for elasticity measurements is justified. We provide an evidence that the alterations of cell elasticity triggered by tumor necrosis factor alpha (TNF-α) in EA.hy926 endothelial cells are preserved after glutaraldehyde (GA) fixation. The value of post-fixation elasticity parameter is a product of the elasticity parameter obtained for living cells and a constant value, dependent on the GA concentration. The modification of the initial value of elasticity parameter caused by remodeling of the cortical actin cytoskeleton is reflected in the elasticity measurements performed on fixed cells. Thus, such fixation procedure may be particularly helpful for experiments, where the influence of an external agent on the cell cortex should be assessed and AFM measurements of living cells are problematic or better statistics is needed.

  9. PreFix™ external fixator used to treat a floating shoulder injury caused by gunshot wound.

    PubMed

    Vogels, J; Pommier, N; Cursolle, J-C; Belin, C; Tournier, C; Durandeau, A

    2014-10-01

    Open fractures of the shoulder are extremely rare, and their treatment is a major challenge for surgeons. Only cases encountered in military settings have been reported thus far. Such fractures are often the result of ballistic trauma, which causes extensive damage to both bony and soft tissues. Since these injuries are associated with a high risk of infection and the presence of comminuted fractures, external fixation is necessary for repair. Use of external fixators and revascularization techniques has reduced the number of cases requiring shoulder amputation or disarticulation. Injury to the proximal extremity of the humerus, acromion, and clavicle further complicates the treatment. No published studies have described the assembly of external fixators for fractures in the scapular region with significant bone loss. In addition, no cases have been described in civilian settings. However, with an increase in urban violence and the traffic of illegal arms, civilian surgeons are now encountering an increasing number of patients with these injuries. In this report, we not only present a rare case of floating shoulder injury in a civilian setting but also provide an overview of the existing treatment strategies for this type of trauma, with special focus on the use of external fixators in elective shoulder arthrodesis and on military cases. PMID:25267396

  10. C2 nerve dysfunction associated with C1 lateral mass screw fixation.

    PubMed

    Huang, Da-geng; Hao, Ding-jun; Li, Guang-lin; Guo, Hao; Zhang, Yu-chen; He, Bao-rong

    2014-11-01

    The C1 lateral mass screw technique is widely used for atlantoaxial fixation. However, C2 nerve dysfunction may occur as a complication of this procedure, compromising the quality of life of affected patients. This is a review of the topic of C2 nerve dysfunction associated with C1 lateral mass screw fixation and related research developments. The C2 nerve root is located in the space bordered superiorly by the posterior arch of C1 , inferiorly by the C2 lamina, anteriorly by the lateral atlantoaxial joint capsule, and posteriorly by the anterior edge of the ligamentum flavum. Some surgeons suggest cutting the C2 nerve root during C1 lateral mass screw placement, whereas others prefer to preserve it. The incidence, clinical manifestations, causes, management, and prevention of C2 nerve dysfunction associated with C(1) lateral mass screw fixation are reviewed. Sacrifice of the C2 nerve root carries a high risk of postoperative numbness, whereas postoperative nerve dysfunction can occur when it has been preserved. Many surgeons have been working hard on minimizing the risk of postoperative C2 nerve dysfunction associated with C1 lateral mass screw fixation. PMID:25430709

  11. Fugitive dust control experiments using soil fixatives on vehicle traffic surfaces

    SciTech Connect

    Winberg, M.R.; Wixom, V.E.

    1992-08-01

    This report presents the results of engineering scale dust control experiments using soil fixative for contamination control during handling of transuranic waste. These experiments focused on controlling dust during retrieval operations of buried waste where waste and soil are intimately mixed. Sources of dust generation during retrieval operations include digging, dumping, and vehicle traffic. Because contaminants are expected to attach to soil particles and move with the generated dust, control of the dust spread may be the key to contamination control. Dust control techniques examined in these experiments include the use of soil fixatives to control generation of fugitive dusts during vehicle traffic operations. Previous experiments conducted in FY 1990 included testing of the soil fixative, ENTAC. These experiments showed that ENTAC was effective in controlling dust generation but had several undesirable properties such as slow cure times and clogged the pumps and application nozzles. Therefore, other products would have to be evaluated to find a suitable candidate. As a result, two soil fixatives were tested in these present experiments, COHEREX-PM, an asphalt emulsion product manufactured by Witco Corporation and FLAMBINDER, a calcium lignosulfonate product manufactured by Flambeau Corporation. The results of the experiments include product performance and recommended application methods for application in a field deployable contamination control unit to be built in FY 1993.

  12. Instillation and Fixation Methods Useful in Mouse Lung Cancer Research.

    PubMed

    Limjunyawong, Nathachit; Mock, Jason; Mitzner, Wayne

    2015-01-01

    The ability to instill live agents, cells, or chemicals directly into the lung without injuring or killing the mice is an important tool in lung cancer research. Although there are a number of methods that have been published showing how to intubate mice for pulmonary function measurements, none are without potential problems for rapid tracheal instillation in large cohorts of mice. In the present paper, a simple and quick method is described that enables an investigator to carry out such instillations in an efficient manner. The method does not require any special tools or lighting and can be learned with very little practice. It involves anesthetizing a mouse, making a small incision in the neck to visualize the trachea, and then inserting an intravenous catheter directly. The small incision is quickly closed with tissue adhesive, and the mice are allowed to recover. A skilled student or technician can do instillations at an average rate of 2 min/mouse. Once the cancer is established, there is frequently a need for quantitative histologic analysis of the lungs. Traditionally pathologists usually do not bother to standardize lung inflation during fixation, and analyses are often based on a scoring system that can be quite subjective. While this may sometime be sufficiently adequate for gross estimates of the size of a lung tumor, any proper stereological quantification of lung structure or cells requires a reproducible fixation procedure and subsequent lung volume measurement. Here we describe simple reliable procedures for both fixing the lungs under pressure and then accurately measuring the fixed lung volume. The only requirement is a laboratory balance that is accurate over a range of 1 mg-300 g. The procedures presented here thus could greatly improve the ability to create, treat, and analyze lung cancers in mice. PMID:26381993

  13. Rinsing of allograft bone does not improve implant fixation

    PubMed Central

    2013-01-01

    Background and purpose Impacted morselized allograft bone is a well-established method for reconstructing bone defects at revision surgery. However, the incorporation of bone graft is not always complete, and a substantial volume of fibrous tissue has been found around grafted implants. We hypothesized that rinsing the bone graft may improve graft incorporation by removing the majority of immunogenic factors present in blood, marrow, and fat. Methods We implanted a cylindrical (10- × 6-mm) porous-coated Ti implant into each proximal tibia of 12 dogs. The implants were surrounded by a 2.5-mm gap into which morselized fresh frozen allograft bone was impacted. The bone graft was either (1) untreated or (2) rinsed in 37°C saline for 3 × 1 min. After 4 weeks, the animals were killed and implant fixation was evaluated by mechanical push-out and histomorphometry. Results The groups (rinsed vs. control) were similar regarding mechanical implant fixation (mean (SD)): shear strength (MPa) 2.7 (1.0) vs. 2.9 (1.2), stiffness (MPa/mm) 15 (6.7) vs. 15 (5.6), and energy absorption (kJ/m2) 0.5 (0.2) vs. 0.6 (0.4), The same was evident for the new bone formation on the implant surface and around the implant: ongrowth (%) 6 vs. 7 and ingrowth (%) 9 vs. 9. Although not statistically significant, a 61% reduction in fibrous tissue ongrowth and 50% reduction in ingrowth were found in the rinsed group. Interpretation Within the limits of this experimental model, we did not detect any benefits of rinsing morselized allograft bone prior to impaction grafting. PMID:23621809

  14. Ocular Fixation Abnormality in Patients with Autism Spectrum Disorder.

    PubMed

    Shirama, Aya; Kanai, Chieko; Kato, Nobumasa; Kashino, Makio

    2016-05-01

    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 individuals were consistent regardless of the presence or absence of a fixation target in the controls, but not in the ASD group. Additionally, fixation stability did not correlate with an ability to suppress reflexive saccades measured by an antisaccade task. These findings suggest that ASD adults have deficits in converting alternative sensory information, such as retinal signals in the peripheral visual field or extraretinal signals, to motor commands when the foveal information is unavailable. PMID:26739354

  15. The serological diagnosis of Mycoplasma pneumoniae infection: a comparison of complement fixation, haemagglutination and immunofluorescence.

    PubMed Central

    Rousseau, S. A.; Tettmar, R. E.

    1985-01-01

    A total of 193 sera were examined for antibody to Mycoplasma pneumoniae by three techniques - complement fixation (CF), haemagglutination (HA) and immunofluorescence (IF), the last method being used to assess IgM, IgG and IgA antibodies. The most reliable single test for diagnosis was HA, and the most useful combination of tests was HA with IF (IgM and IgG). The IgA IF was not found to be diagnostically helpful. PMID:3934260

  16. Gaze shifts and fixations dominate gaze behavior of walking cats

    PubMed Central

    Rivers, Trevor J.; Sirota, Mikhail G.; Guttentag, Andrew I.; Ogorodnikov, Dmitri A.; Shah, Neet A.; Beloozerova, Irina N.

    2014-01-01

    Vision is important for locomotion in complex environments. How it is used to guide stepping is not well understood. We used an eye search coil technique combined with an active marker-based head recording system to characterize the gaze patterns of cats walking over terrains of different complexity: (1) on a flat surface in the dark when no visual information was available, (2) on the flat surface in light when visual information was available but not required, (3) along the highly structured but regular and familiar surface of a horizontal ladder, a task for which visual guidance of stepping was required, and (4) along a pathway cluttered with many small stones, an irregularly structured surface that was new each day. Three cats walked in a 2.5 m corridor, and 958 passages were analyzed. Gaze activity during the time when the gaze was directed at the walking surface was subdivided into four behaviors based on speed of gaze movement along the surface: gaze shift (fast movement), gaze fixation (no movement), constant gaze (movement at the body’s speed), and slow gaze (the remainder). We found that gaze shifts and fixations dominated the cats’ gaze behavior during all locomotor tasks, jointly occupying 62–84% of the time when the gaze was directed at the surface. As visual complexity of the surface and demand on visual guidance of stepping increased, cats spent more time looking at the surface, looked closer to them, and switched between gaze behaviors more often. During both visually guided locomotor tasks, gaze behaviors predominantly followed a repeated cycle of forward gaze shift followed by fixation. We call this behavior “gaze stepping”. Each gaze shift took gaze to a site approximately 75–80 cm in front of the cat, which the cat reached in 0.7–1.2 s and 1.1–1.6 strides. Constant gaze occupied only 5–21% of the time cats spent looking at the walking surface. PMID:24973656

  17. Machining of a bioactive nanocomposite orthopedic fixation device.

    PubMed

    Sparnell, Amie; Aniket; El-Ghannam, Ahmed

    2012-08-01

    Bioactive ceramics bond to bone and enhance bone formation. However, they have poor mechanical properties which restrict their machinability as well as their application as load bearing implants. The goal of this study was to machine bioactive fixation screws using a silica-calcium phosphate nanocomposite (SCPC50). The effect of compact pressure, holding time, and thermal treatment on the microstructure, machinability, and mechanical properties of SCPC50 cylinders were investigated. Samples prepared by powder metallurgy technique at compact pressure range of 100-300 MPa and treated at 900°C/1 h scored a poor machinability rating of (1/5) due to the significant formation of amorphous silicate phase at the grain boundaries. On the other hand, lowering of compact pressure and sintering temperature to 30 MPa/3 h and 700°C/2 h, respectively, minimized the formation of the amorphous phase and raised the machinability rating to (5/5). The modulus of elasticity and ultimate strength of machinable SCPC50 were 10.8 ± 2.0 GPa and 72.8 ± 22.8 MPa, respectively, which are comparable to the corresponding values for adult human cortical bone. qRT-PCR analyses showed that bone cells attached to SCPC50 significantly upregulated osteocalcin mRNA expression as compared to the cells on Ti-6Al-4V. Moreover, cells attached to SCPC50 produced mineralized bone-like tissue within 8 days. On the other hand, cells attached to Ti-6Al-4V failed to produce bone mineral under the same experimental conditions. Results of the study suggest that machinable SCPC50 has the potential to serve as an attractive new material for orthopedic fixation devices.

  18. Transient cortical excitation at the onset of visual fixation.

    PubMed

    Rajkai, Csaba; Lakatos, Peter; Chen, Chi-Ming; Pincze, Zsuzsa; Karmos, Gyorgy; Schroeder, Charles E

    2008-01-01

    Primates actively examine the visual world by rapidly shifting gaze (fixation) over the elements in a scene. Despite this fact, we typically study vision by presenting stimuli with gaze held constant. To better understand the dynamics of natural vision, we examined how the onset of visual fixation affects ongoing neuronal activity in the absence of visual stimulation. We used multiunit activity and current source density measurements to index neuronal firing patterns and underlying synaptic processes in macaque V1. Initial averaging of neural activity synchronized to the onset of fixation suggested that a brief period of cortical excitation follows each fixation. Subsequent single-trial analyses revealed that 1) neuronal oscillation phase transits from random to a highly organized state just after the fixation onset, 2) this phase concentration is accompanied by increased spectral power in several frequency bands, and 3) visual response amplitude is enhanced at the specific oscillatory phase associated with fixation. We hypothesize that nonvisual inputs are used by the brain to increase cortical excitability at fixation onset, thus "priming" the system for new visual inputs generated at fixation. Despite remaining mechanistic questions, it appears that analysis of fixation-related responses may be useful in studying natural vision.

  19. Stoppa Approach for Anterior Plate Fixation in Unstable Pelvic Ring Injury

    PubMed Central

    Choo, Suk Kyu; Kim, Jung-Jae; Lee, Mark

    2016-01-01

    Background The Stoppa (intrapelvic) approach has been introduced for the treatment of pelvic-acetabular fractures; it allows easy exposure of the pelvic brim, where the bone quality is optimal for screw fixation. The purpose of our study was to investigate the surgical outcomes of unstable pelvic ring injuries treated using the Stoppa approach for stable anterior ring fixation. Methods We analyzed 22 cases of unstable pelvic ring injury treated with plate fixation of the anterior ring with the Stoppa approach. We excluded cases of nondisplaced rami fracture, simple symphyseal diastasis, and parasymphyseal fractures, which can be easily treated with other techniques. The average age of the study patients was 41 years (range, 23 to 61 years). There were 10 males and 12 females. According to the Young and Burgess classification, there were 12 lateral compression, 4 anteroposterior compression, and 6 vertical shear fracture patterns. The fracture location on the anterior ring was near the iliopectineal eminence in all cases and exposure of the pelvic brim was required for plate fixation. All patients were placed in the supine position. For anterior plate fixation, all screws were applied to the anterior ramus distally and directed above the hip joint proximally. Radiologic outcomes were assessed by union time and quality of reduction by Matta method. The Merle d'Aubigne-Postel score was used to evaluate the functional results. Results The average radiologic follow-up period was 16 months (range, 10 to 51 months). All fractures united at an average of 3.5 months (range, 3 to 5 months). According to the Matta method, the quality of reduction was classified as follows: 16 anatomical (73%) and 6 nearly anatomical (27%) reductions. There were no cases of screw or implant loosening before bone healing. The functional results were classified as 7 excellent (32%), 12 good (55%), and 3 fair (13%) by the Merle d'Aubigne-Postel score. There were no wound complications

  20. 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

  1. 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.

  2. Atlantoaxial Rotatory Fixation in Adults Patient

    PubMed Central

    Jeon, Sei Woong; Moon, Seung Myung; Choi, Sun Kil

    2009-01-01

    Atlantoaxial rotatory fixation (AARF) in adult is a rare disorder that occurs followed by a trauma. The patients were presented with painful torticollis and a typical 'cock robin' position of the head. The clinical diagnosis is generally difficult and often made in the late stage. In some cases, an irreducible or chronic fixation develops. We reported a case of AARF in adult patient which was treated by immobilization with conservative treatment. A 25-year-old female was presented with a posterior neck pain and limitation of motion of cervical spine after a traffic accident. She had no neurological deficit but suffered from severe defect on the scalp and multiple thoracic compression fractures. Plain radiographs demonstrated torticollis, lateral shift of odontoid process to one side and widening of one side of C1-C2 joint space. Immobilization with a Holter traction were performed and analgesics and muscle relaxants were given. Posterior neck pain and limitation of the cervical spine's motion were resolved. Plain cervical radiographs taken at one month after the injury showed that torticollis disappeared and the dens were in the midline position. The authors reported a case of type I post-traumatic AARF that was successfully treated by immobilization alone. PMID:19444353

  3. Influence of tree canopy on N₂ fixation by pasture legumes and soil rhizobial abundance in Mediterranean oak woodlands.

    PubMed

    Carranca, C; Castro, I V; Figueiredo, N; Redondo, R; Rodrigues, A R F; Saraiva, I; Maricato, R; Madeira, M A V

    2015-02-15

    Symbiotic N2 fixation is of primordial significance in sustainable agro-forestry management as it allows reducing the use of mineral N in the production of mixed stands and by protecting the soils from degradation. Thereby, on a 2-year basis, N2 fixation was evaluated in four oak woodlands under Mediterranean conditions using a split-plot design and three replicates. (15)N technique was used for determination of N2 fixation rate. Variations in environmental conditions (temperature, rainfall, radiation) by the cork tree canopy as well as the age of stands and pasture management can cause great differences in vegetation growth, legume N2 fixation, and soil rhizobial abundance. In the present study, non-legumes dominated the swards, in particular beneath the tree canopy, and legumes represented only 42% of total herbage. A 2-fold biomass reduction was observed in the oldest sown pasture in relation to the medium-age sward (6 t DW ha(-1)yr(-1)). Overall, competition of pasture growth for light was negligible, but soil rhizobial abundance and symbiotic N2 fixation capacity were highly favored by this environmental factor in the spring and outside the influence of tree canopy. Nitrogen derived from the atmosphere was moderate to high (54-72%) in unsown and sown swards. Inputs of fixed N2 increased from winter to spring due to more favorable climatic conditions (temperature and light intensity) for both rhizobia and vegetation growths. Assuming a constant fixation rate at each seasonal period, N2 fixation capacity increased from about 0.10 kg N ha(-1) per day in the autumn-winter period to 0.15 kg N ha(-1) per day in spring. Belowground plant material contributed to 11% of accumulated N in pasture legumes and was not affected by canopy. Size of soil fixing bacteria contributed little to explain pasture legumes N.

  4. Plasticity of fixation in patients with central vision loss.

    PubMed

    Tarita-Nistor, Luminita; González, Esther G; Markowitz, Samuel N; Steinbach, Martin J

    2009-11-01

    The aim of this study was to explore the plasticity of fixation in patients with central vision loss. Most of these patients use preferred retinal loci (PRLs) in the healthy eccentric part of the retina to fixate, but fixation stability and retinal location are not always optimal for best visual performance. This study examined whether fixation stability and a new PRL location can be trained and whether these changes in ocular motor control transfer into better reading performance. Six patients with age-related macular degeneration participated in the study. Fixation stability measurements, microperimetry, and auditory biofeedback training were performed with the MP-1 microperimeter. The auditory biofeedback was used during five 1-h long training sessions to improve fixation and relocate the PRL. Fixation location and stability were recorded while viewing four different targets: a cross, a letter, a word, and a nine-cycle radial grating. Visual acuity was assessed with the Early Treatment Diabetic Retinopathy Study (ETDRS) chart and reading performance with the MNRead test. The results showed that all patients developed a new PRL in an optimal location for reading, and they were able to use it consistently while viewing different targets. Fixation stability improved 53% after training. Learning transferred to the old PRL even though fixation stability at this location was not trained. All these improvements in ocular motor control translated into better reading performance: reading speed improved 38% and reading acuity and critical print size gained two lines. We conclude that the ability of the ocular motor system to fixate is flexible in patients with central vision loss: a new PRL can be trained, fixation stability can be improved, and learning transfers to an untrained location. These gains in ocular motor control result in better visual performance. This property can be successfully used to optimize the residual vision of patients with central vision loss.

  5. [Arthroscopic fracture fixation of intercondylar eminence in children using instrumentarium for the reconstruction of anterior cruciate ligament].

    PubMed

    Sleczka, Paweł; Krzywoń, Jerzy; Ambrozy, Wojciech

    2010-01-01

    In our article we introduce a proposal of intercondylar tibial eminence fracture in children management. When dealing with II and III type fracture according to Mes and McKeever classification, we would like to suggest artroscopic fracture fixation with the help of a tension band wiring technique using single bundle reconstruction set of anterior cruciate ligament.The method mentioned above was presented on two cases managed in our ward. Stable fixation of this type fracture allows for quick mobilization and physiotherapy of a patient. It appears to be the key element to full recovery in articular surface fracture. PMID:21648155

  6. Visualization of the effects of electron microscopy fixatives on the structure of hydrated epidermal hairs of tomato (lycopersicum peruvianum) as revealed by soft x-ray contact microscopy

    NASA Astrophysics Data System (ADS)

    Stead, Anthony D.; Cotton, Robin A.; Page, Anton M.; Dooley, Mike D.; Ford, Thomas W.

    1993-01-01

    In order to examine the ultrastructure of biological specimens by electron microscopy it is necessary to stabilize the highly labile cellular contents before embedding and sectioning the specimens. This is commonly achieved by treating the tissues with various chemical fixatives. The assessment of the efficacy of these fixative is usually based upon the appearance of the specimen under the microscope although this is somewhat intuitive as the ultrastructure of the living cell cannot be studied. Previous studies, in which the structure of epidermal hairs has been followed under the light microscope as the commonly used fixatives are perfused into the tissue, have shown that the cellular contents are drastically rearranged by these fixatives. This paper describes the effects of some of the commonly used fixatives on cell ultrastructure using firstly electron microscopy and secondly soft x-ray contact microscopy. The latter technique allows not only direct comparisons of the effects of the fixatives but also allows living, hydrated specimens to be imaged so that the true ultrastructural effects of the fixatives can be seen and compared to the ultrastructure of the living material.

  7. Phosphoribulokinase mediates nitrogenase-induced carbon dioxide fixation gene repression in Rhodobacter sphaeroides

    PubMed Central

    Farmer, Ryan M.

    2015-01-01

    In many organisms there is a balance between carbon and nitrogen metabolism. These observations extend to the nitrogen-fixing, nonsulfur purple bacteria, which have the classic family of P(II) regulators that coordinate signals of carbon and nitrogen status to regulate nitrogen metabolism. Curiously, these organisms also possess a reverse mechanism to regulate carbon metabolism based on cellular nitrogen status. In this work, studies in Rhodobacter sphaeroides firmly established that the activity of the enzyme that catalyses nitrogen fixation, nitrogenase, induces a signal that leads to repression of genes encoding enzymes of the Calvin–Benson–Bassham (CBB) CO2 fixation pathway. Additionally, genetic and metabolomic experiments revealed that NADH-activated phosphoribulokinase is an intermediate in the signalling pathway. Thus, nitrogenase activity appears to be linked to cbb gene repression through phosphoribulokinase. PMID:26306848

  8. Effect of insecticides and phenolics on nitrogen fixation by Nostoc linckia

    SciTech Connect

    Megharaj, M.; Venkateswarlu, K.; Rao, A.S.

    1988-08-01

    The nitrogen-fixing blue-green algae (cyanobacteria) significantly influence the nitrogen economy of temperate and tropical soils. Although the genera Nostoc and Tolypothrix have been particularly implicated in the fixation of significantly large amounts of atmospheric nitrogen, these diazotrophs received little attention in relation to insecticide treatment and the available few reports do not indicate a permanent deleterious effect of insecticides on their nitrogenase activity. As it has been well established that the effect of insecticides on nitrogen fixation by cyanobacteria is independent of that on growth, an attempt was, therefore, made to determine the influence of four insecticides (monocrotophos, quinalphos, cypermethrin and fenvalerate) and four phenolics (p-nitrophenol (PNP), m-nitrophenol (MNP), 2,4-dinitrophenol (DNP) and catechol) on nitrogen-fixing capacity of N.linckia, isolated from a black soil.

  9. Phosphoribulokinase mediates nitrogenase-induced carbon dioxide fixation gene repression in Rhodobacter sphaeroides.

    PubMed

    Farmer, Ryan M; Tabita, F Robert

    2015-11-01

    In many organisms there is a balance between carbon and nitrogen metabolism. These observations extend to the nitrogen-fixing, nonsulfur purple bacteria, which have the classic family of P(II) regulators that coordinate signals of carbon and nitrogen status to regulate nitrogen metabolism. Curiously, these organisms also possess a reverse mechanism to regulate carbon metabolism based on cellular nitrogen status. In this work, studies in Rhodobacter sphaeroides firmly established that the activity of the enzyme that catalyses nitrogen fixation, nitrogenase, induces a signal that leads to repression of genes encoding enzymes of the Calvin-Benson-Bassham (CBB) CO2 fixation pathway. Additionally, genetic and metabolomic experiments revealed that NADH-activated phosphoribulokinase is an intermediate in the signalling pathway. Thus, nitrogenase activity appears to be linked to cbb gene repression through phosphoribulokinase.

  10. Measurement of symbiotic nitrogen-fixation in leguminous host-plants grown in heavy metal-contaminated soils amended with sewage sludge.

    PubMed

    Obbard, J P; Jones, K C

    2001-01-01

    Rates of nitrogen fixation by Rhizobium in symbiosis with leguminous host-plants including white clover, broad bean and peas have been established in soils that have been amended experimentally with heavy metal-contaminated sewage sludges. Results from 15N-dilution experiments for the measurement of N2 fixation have shown that adverse heavy metal effects are apparent on symbiotic N2 fixation rates for white clover grown in inter-specific competition with ryegrass under mixed sward conditions, compared to white clover grown in pure sward. Further experiments on broad bean and pea indicated a significant, but minor-inhibitory metal-related effect on the rate of N2 fixation compared to untreated soils and soils amended with a relatively uncontaminated sludge. The implications of the results with respect to sludge utilisation in agriculture are discussed.

  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. Carbon sequestration in soybean crop soils: the role of hydrogen-coupled CO2 fixation

    NASA Astrophysics Data System (ADS)

    Graham, A.; Layzell, D. B.; Scott, N. A.; Cen, Y.; Kyser, T. K.

    2011-12-01

    Conversion of native vegetation to agricultural land in order to support the world's growing population is a key factor contributing to global climate change. However, the extent to which agricultural activities contribute to greenhouse gas emissions compared to carbon storage is difficult to ascertain, especially for legume crops, such as soybeans. Soybean establishment often leads to an increase in N2O emissions because N-fixation leads to increased soil available N during decomposition of the low C:N legume biomass. However, soybean establishment may also reduce net greenhouse gas emissions by increasing soil fertility, plant growth, and soil carbon storage. The mechanism behind increased carbon storage, however, remains unclear. One explanation points to hydrogen coupled CO2 fixation; the process by which nitrogen fixation releases H2 into the soil system, thereby promoting chemoautotrophic carbon fixation by soil microbes. We used 13CO2 as a tracer to track the amount and fate of carbon fixed by hydrogen coupled CO2 fixation during one-year field and laboratory incubations. The objectives of the research are to 1) quantify rates of 13CO2 fixation in soil collected from a field used for long-term soybean production 2) examine the impact of H2 gas concentration on rates of 13CO2 fixation, and 3) measure changes in δ13C signature over time in 3 soil fractions: microbial biomass, light fraction, and acid stable fraction. If this newly-fixed carbon is incorporated into the acid-stable soil C fraction, it has a good chance of contributing to long-term soil C sequestration under soybean production. Soil was collected in the field both adjacent to root nodules (nodule soil) and >3cm away (root soil) and labelled with 13CO2 (1% v/v) in the presence and absence of H2 gas. After a two week labelling period, δ13C signatures already revealed differences in the four treatments of bulk soil: -17.1 for root, -17.6 for nodule, -14.2 for root + H2, and -6.1 for nodule + H2

  13. What is new in distal femur periprosthetic fracture fixation?

    PubMed

    Tosounidis, Theodoros H; Giannoudis, Peter V

    2015-12-01

    Distal femoral periprosthetic fractures are on the rise. Increased mortality of these injuries is also evident from recent data. Their incidence and risk factors have been extensively reported in the past but new data are being available that merit attention. The increased incidence and the even higher projected incidence should direct the focus of future strategies to the education of surgeons, relevant capacity of hospital and reconfiguration of health care resources. New and potentially modifiable risk factors should be taken into consideration to the informed consent process and new studies should be developed to clarify the causative relationship of the new risk factors such as the peptic ulcer disease and the COPD. The main internal fixation techniques remain the lateral locking plating and the retrograde intramedullary nailing. New techniques in plating are the supplementary medial plate in selected cases and the far cortical locking. Nailing is considered a valid option especially in fractures located well above the anterior flange of the femoral component of the arthroplasty. Results and outcomes from good quality studies are still sparse regarding the comparison between plating and nailing. Interprosthetic fractures constitute an entity that is lately gaining considerable attention. The best method of management of these injuries is still evolving with considerable amount of work being done in the clinical and biomechanical level.

  14. Simple clearing technique as species determination tool in blowfly larvae.

    PubMed

    Niederegger, Senta; Wartenberg, Nelly; Spiess, Roland; Mall, Gita

    2011-03-20

    A simple clearing technique is presented by which species specific structures and organs of blowfly larvae can easily be visualized and displayed without any danger of mechanical damages or dislocations of delicate formations and without fixation of the object.

  15. 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

  16. 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

    internal rotation during a simulated pivot shift (combined 5 N-m internal rotation and 10 N-m valgus torques) were recorded between 0° and 60°. Kinematic changes were measured and compared to the native state for all reconstructed and sectioned states. Results: Anterolateral ligament reconstruction at all graft fixation angles significantly reduced internal rotation of the knee with respect to the ACLR with sectioned ALL state at all knee flexion angles beyond 30° (Figure 1). However, ALLR overconstrained the knee joint at each tested ALL graft fixation angle and through all tested knee flexion angles beyond 15° during simulated internal rotation torque and pivot shift tests (Figure 1). Furthermore, no significant difference was observed between the different graft fixation angles on the kinematics of the knee with respect to anterior drawer, pivot shift and internal rotation. Conclusion: Anatomic ALLR in conjunction with an ACLR overconstrained internal rotation of the knee joint at flexion angles beyond 15° regardless of graft fixation angle. The surgical technique and indications for this procedure should be investigated further and it is recommended that ALLR be used with caution.

  17. 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.…

  18. 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)

  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. Modeling evolution using the probability of fixation: history and implications.

    PubMed

    McCandlish, David M; Stoltzfus, Arlin

    2014-09-01

    Many models of evolution calculate the rate of evolution by multiplying the rate at which new mutations originate within a population by a probability of fixation. Here we review the historical origins, contemporary applications, and evolutionary implications of these "origin-fixation" models, which are widely used in evolutionary genetics, molecular evolution, and phylogenetics. Origin-fixation models were first introduced in 1969, in association with an emerging view of "molecular" evolution. Early origin-fixation models were used to calculate an instantaneous rate of evolution across a large number of independently evolving loci; in the 1980s and 1990s, a second wave of origin-fixation models emerged to address a sequence of fixation events at a single locus. Although origin fixation models have been applied to a broad array of problems in contemporary evolutionary research, their rise in popularity has not been accompanied by an increased appreciation of their restrictive assumptions or their distinctive implications. We argue that origin-fixation models constitute a coherent theory of mutation-limited evolution that contrasts sharply with theories of evolution that rely on the presence of standing genetic variation. A major unsolved question in evolutionary biology is the degree to which these models provide an accurate approximation of evolution in natural populations.

  1. 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.

  2. 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...

  3. 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

  4. Rapid resonance Raman microspectroscopy to probe carbon dioxide fixation by single cells in microbial communities

    PubMed Central

    Li, Mengqiu; Canniffe, Daniel P; Jackson, Philip J; Davison, Paul A; FitzGerald, Simon; Dickman, Mark J; Burgess, J Grant; Hunter, C Neil; Huang, Wei E

    2012-01-01

    Photosynthetic microorganisms play crucial roles in aquatic ecosystems and are the major primary producers in global marine ecosystems. The discovery of new bacteria and microalgae that play key roles in CO2 fixation is hampered by the lack of methods to identify hitherto-unculturable microorganisms. To overcome this problem we studied single microbial cells using stable-isotope probing (SIP) together with resonance Raman (RR) microspectroscopy of carotenoids, the light-absorbing pigments present in most photosynthetic microorganisms. We show that fixation of 13CO2 into carotenoids produces a red shift in single-cell RR (SCRR) spectra and that this SCRR–SIP technique is sufficiently sensitive to detect as little as 10% of 13C incorporation. Mass spectrometry (MS) analysis of labelled cellular proteins verifies that the red shift in carotenoid SCRR spectra acts as a reporter of the 13C content of single cells. Millisecond Raman imaging of cells in mixed cultures and natural seawater samples was used to identify cells actively fixing CO2, demonstrating that the SCRR–SIP is a noninvasive method for the rapid and quantitative detection of CO2 fixation at the single cell level in a microbial community. The SCRR–SIP technique may provide a direct method for screening environmental samples, and could help to reveal the ecophysiology of hitherto-unculturable microorganisms, linking microbial species to their ecological function in the natural environment. PMID:22113377

  5. Fixation and escape times in stochastic game learning

    NASA Astrophysics Data System (ADS)

    Realpe-Gomez, John; Szczesny, Bartosz; Dall'Asta, Luca; Galla, Tobias

    2012-10-01

    Evolutionary dynamics in finite populations is known to fixate eventually in the absence of mutation. We here show that a similar phenomenon can be found in stochastic game dynamical batch learning, and investigate fixation in learning processes in a simple 2×2 game, for two-player games with cyclic interaction, and in the context of the best-shot network game. The analogues of finite populations in evolution are here finite batches of observations between strategy updates. We study when and how such fixation can occur, and present results on the average time-to-fixation from numerical simulations. Simple cases are also amenable to analytical approaches and we provide estimates of the behaviour of so-called escape times as a function of the batch size. The differences and similarities with escape and fixation in evolutionary dynamics are discussed.

  6. Time course of visual information utilization during fixations in reading.

    PubMed

    Blanchard, H E; McConkie, G W; Zola, D; Wolverton, G S

    1984-02-01

    College students read short texts from a cathode-ray tube as their eye movements were being monitored. During selected fixations, the text was briefly masked and then it reappeared with one word changed. Subjects often were unaware that the word had changed. Sometimes they reported seeing the first presented word, sometimes the second presented word, and sometimes both. When only one word was reported, two factors were found to determine which one it was: the length of time a word was present during the fixation and the predictability of a word in its context. The results suggested that visual information is utilized for reading at a crucial period during the fixation and that this crucial period can occur at different times on different fixations. The pattern of responses suggested that the first letter of a word is not utilized before other letters and that letters are not scanned from left to right during a fixation.

  7. Laminar screw fixation in the subaxial cervical spine: A report on three cases

    PubMed Central

    Tanabe, Hironori; Aota, Yoichi; Saito, Tomoyuki

    2016-01-01

    Although laminar screw fixation is often used at the C2 and C7 levels, only few previous case reports have presented the use of laminar screws at the C3-C6 levels. Here, we report a novel fixation method involving the use of practical laminar screws in the subaxial spine. We used laminar screws in the subaxial cervical spine in two cases to prevent vertebral artery injury and in one case to minimize exposure of the lamina. This laminar screw technique was successful in all three cases with adequate spinal rigidity, which was achieved without complications. The use of laminar screws in the subaxial cervical spine is a useful option for posterior fusion of the cervical spine. PMID:27795952

  8. Stress fractures of the femur after ACL reconstruction with transfemoral fixation.

    PubMed

    Arriaza, Rafael; Señaris, Jose; Couceiro, Gonzalo; Aizpurua, Jesus

    2006-11-01

    The ACL reconstruction with hamstring tendons has become increasingly popular, in part because it is assumed that the complication rate associated with the technique and their severity are lower than with patellar tendon. Two cases of stress reaction of the medial supracondylar area of the femur after ACL reconstruction with hamstring tendons using BioTransfix (Arthrex, Naples, FL, USA) devices for fixation within femur are presented. Both patients were professional athletes (one soccer and one basketball player), and it is hypothesized that the accelerated rehabilitation program used might have represented a risk factor for stress fractures when associated with the guide pin exit hole in the medial femoral cortex. To our knowledge, no such cases have been published to date, but it is important to consider this possibility if an unexplained pain arises in the rehabilitation process of an ACL reconstruction using transfemoral fixation.

  9. Establishing Rapport with Deviant Groups

    ERIC Educational Resources Information Center

    Berk, Richard A.; Adams, Joseph M.

    1970-01-01

    Techniques recommended for establishing and maintaining rapport with deviant groups focus on overcoming problems of social distance and mistrust. Although based on experience with juvenile delinquents and drug addicts, the suggestions made are held to offer potential for wider applicability. (RJ)

  10. Arthroscopic fixation of cell free polymer-based cartilage implants with a bioinspired polymer surface on the hip joint: a cadaveric pilot study.

    PubMed

    Lahner, Matthias; Duif, Christian; Ficklscherer, Andreas; Kaps, Christian; Kalwa, Lukas; Seidl, Tobias

    2014-01-01

    This study investigates the adhesion capacity of a polyglycolic acid- (PGA-) hyaluronan scaffold with a structural modification based on a planar polymer (PM) surface in a cadaver cartilage defect model. Two cadaver specimens were used to serially test multiple chondral matrices. In a cadaver hip model, cell free polymer-based cartilage implants with a planar bioinspired PM surface (PGA-PM-scaffolds) were implanted arthroscopically on 10 mm × 15 mm full-thickness femoral hip cartilage lesions. Unprocessed cartilage implants without a bioinspired PM surface were used as control group. The cartilage implants were fixed without and with the use of fibrin glue on femoral hip cartilage defects. After 50 movement cycles and removal of the distraction, a rearthroscopy was performed to assess the outline attachment and integrity of the scaffold. The fixation techniques without and with fibrin fixation showed marginal differences for outline attachment, area coverage, scaffold integrity, and endpoint fixation after 50 cycles. The PGA-PM-scaffolds with fibrin fixation achieved a higher score in terms of the attachment, integrity, and endpoint fixation than the PGA-scaffold on the cartilage defect. Relating to the outline attachment, area coverage, scaffold integrity, and endpoint fixation, the fixation with PGA-PM-scaffolds accomplished significantly better results compared to the PGA-scaffolds (P = 0.03752, P = 0.03078, P = 0.00512, P = 0.00512). PGA-PM-scaffolds demonstrate increased observed initial fixation strength in cadaver femoral head defects relative to PGA-scaffold, particularly when fibrin glue is used for fixation.

  11. Arthroscopic Fixation of Cell Free Polymer-Based Cartilage Implants with a Bioinspired Polymer Surface on the Hip Joint: A Cadaveric Pilot Study

    PubMed Central

    Lahner, Matthias; Duif, Christian; Ficklscherer, Andreas; Kaps, Christian; Kalwa, Lukas; Seidl, Tobias

    2014-01-01

    This study investigates the adhesion capacity of a polyglycolic acid- (PGA-) hyaluronan scaffold with a structural modification based on a planar polymer (PM) surface in a cadaver cartilage defect model. Two cadaver specimens were used to serially test multiple chondral matrices. In a cadaver hip model, cell free polymer-based cartilage implants with a planar bioinspired PM surface (PGA-PM-scaffolds) were implanted arthroscopically on 10 mm × 15 mm full-thickness femoral hip cartilage lesions. Unprocessed cartilage implants without a bioinspired PM surface were used as control group. The cartilage implants were fixed without and with the use of fibrin glue on femoral hip cartilage defects. After 50 movement cycles and removal of the distraction, a rearthroscopy was performed to assess the outline attachment and integrity of the scaffold. The fixation techniques without and with fibrin fixation showed marginal differences for outline attachment, area coverage, scaffold integrity, and endpoint fixation after 50 cycles. The PGA-PM-scaffolds with fibrin fixation achieved a higher score in terms of the attachment, integrity, and endpoint fixation than the PGA-scaffold on the cartilage defect. Relating to the outline attachment, area coverage, scaffold integrity, and endpoint fixation, the fixation with PGA-PM-scaffolds accomplished significantly better results compared to the PGA-scaffolds (P = 0.03752, P = 0.03078, P = 0.00512, P = 0.00512). PGA-PM-scaffolds demonstrate increased observed initial fixation strength in cadaver femoral head defects relative to PGA-scaffold, particularly when fibrin glue is used for fixation. PMID:25247185

  12. In vivo bone tunnel remodeling in symptomatic patients after ACL reconstruction: a retrospective comparison of articular and extra-articular fixation

    PubMed Central

    Mathis, Dominic T.; Rasch, Helmut; Hirschmann, Michael T.

    2015-01-01

    Summary Background there is only a paucity of studies dealing with bone remodeling within the tunnels after anterior cruciate ligament (ACL) reconstruction. The objective of this study was to evaluate the influence of tendon graft type and surgical fixation technique on bone tunnel remodeling in patients with symptomatic knees after ACL reconstruction. Methods in a retrospective study 99mTc-HDP bone tracer uptake (BTU) in SPECT/CT of 57 knees with symptoms of pain and/or instability after ACL reconstruction was investigated. All 57 knees were subdivided according their anatomy (femur and tibia), fixation (articular versus extra-articular fixation) and graft types into eight groups: femoral-articular versus extra-articular fixation using bone-patellar tendon-bone (BPTB) and hamstring autografts; tibial-articular versus extra-articular fixation using patellar tendon and hamstring autografts; BTU grading for each area of the localisation scheme were recorded. Tunnel diameter and length was measured in the CT scans. Results BTU was higher for the articular fixation in the femur and for the extra-articular fixation in the tibial tunnel. Patellar tendon graft fixation showed a significantly higher BTU in the superior-lateral and posterior-central area of the tibia, meaning the areas of the tibial tunnel near the entrance into the joint. Tunnel enlargement correlated significantly with increased BTU (p<0.05). Conclusion assessment of in vivo bone tunnel remodelling in symptomatic patients after ACL reconstruction revealed different patterns of BTU with regards to graft and fixation method. PMID:26958543

  13. 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

  14. Surgical outcome following arthroscopic fixation of acromioclavicular joint disruption with the tightrope device.

    PubMed

    Thiel, Eric; Mutnal, Amar; Gilot, Gregory J

    2011-07-07

    The objective of this study was to evaluate the preliminary radiographic and clinical results of grade IV and V acromioclavicular joint disruption repair using the arthroscopic Arthrex acromioclavicular TightRope (Naples, Florida) fixation technique. Numerous procedures have been described for surgical management of acromioclavicular joint disruption. The TightRope device involves an arthroscopic technique that allows nonrigid anatomic fixation of the acromioclavicular joint. A cohort of 10 men and 2 women with a mean age of 43 years (range, 25-61 years) underwent the acromioclavicular joint TightRope procedure between April 2007 and October 2009. Eleven patients had either Rockwood grade IV or V disruptions and 1 sustained a distal third clavicle fracture with acromioclavicular joint disruption. Data was collected from a chart review. Patients were evaluated clinically, radiographically, by the simple shoulder test, and by overall satisfaction. There were 2 failures of reduction and 1 loss of reduction at final radiographic follow-up. The rate of fixation failure was 16.6%. All patients had >110° of total elevation. The majority of patients obtained satisfactory functional results according to the Simple Shoulder Test averaging 11 of 12 questions answered positively (range, 7-12; standard deviation, 1.50) and 11 of 12 patients were satisfied with the procedure. At final phone interview at approximately 2 years postoperatively, 6 patients were lost to follow-up. The remaining patients were all satisfied with the procedure and no patients reported subjective loss of reduction or deterioration of function. Simple Shoulder Test average was maintained with 11 of 12 positively answered questions (range, 7-12; standard deviation, 2.0) This case series revealed a high rate of fixation failure with the TightRope system. Still, most patients were satisfied with the procedure and achieved high functional shoulder results.

  15. 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

  16. Failed distal biceps tendon repair using a single-incision EndoButton technique and its successful treatment: case report.

    PubMed

    Desai, Shaunak S; Larkin, Brian J; Najibi, Soheil

    2010-12-01

    Surgical repair has become a mainstay in the treatment of ruptures of the distal biceps tendon and multiple surgical techniques have been described advocating anatomic or near-anatomic repair. Fixation with an EndoButton technique has been shown to have superior fixation strength and durable clinical outcomes. Here, we describe a case of failed EndoButton fixation of the distal biceps tendon, and its successful treatment. PMID:21115300

  17. A Meta-Analysis for Postoperative Complications in Tibial Plafond Fracture: Open Reduction and Internal Fixation Versus Limited Internal Fixation Combined With External Fixator.

    PubMed

    Wang, Dong; Xiang, Jian-Ping; Chen, Xiao-Hu; Zhu, Qing-Tang

    2015-01-01

    The treatment of tibial plafond fractures is challenging to foot and ankle surgeons. Open reduction and internal fixation and limited internal fixation combined with an external fixator are 2 of the most commonly used methods of tibial plafond fracture repair. However, conclusions regarding the superior choice remain controversial. The present meta-analysis aimed to quantitatively compare the postoperative complications between open reduction and internal fixation and limited internal fixation combined with an external fixator for tibial plafond fractures. Nine studies with 498 fractures in 494 patients were included in the present study. The meta-analysis found no significant differences in bone healing complications (risk ratio [RR] 1.17, 95% confidence interval [CI] 0.68 to 2.01, p = .58], nonunion (RR 1.09, 95% CI 0.51 to 2.36, p = .82), malunion or delayed union (RR 1.24, 95% CI 0.57 to 2.69, p = .59), superficial (RR 1.56, 95% CI 0.43 to 5.61, p = .50) and deep (RR 1.89, 95% CI 0.62 to 5.80) infections, arthritis symptoms (RR 1.20, 95% CI 0.92 to 1.58, p = .18), or chronic osteomyelitis (RR 0.31, 95% CI 0.05 to 1.84, p = .20) between the 2 groups.

  18. Comparison of open reduction internal fixation and conservative treatment plus open reduction internal fixation for calcaneal fractures

    PubMed Central

    Pan, Yongmiao; Yuan, Linyi; Ye, Chengfeng

    2014-01-01

    To compare the effect of open reduction internal fixation and conservative treatment combined with open reduction internal fixation for subjects with calcaneal fractures, 130 patients with calcaneal fractures were divided into observation group and control group. Observation group were treated with open reduction internal fixation and conservative treatment, control group treated as open reduction internal fixation. The healing related indicators, daily life activities ability score of observation group after treatment 6 months were significantly higher than that of the control group, there was no significant difference for the healing rate of excellent and good rate, the daily life activities ability score after one and three year between two groups. Open reduction internal fixation combined with conservative treatment in treatment of calcaneal fractures can clear anatomic structure and have fast function recovery. Thus, it should be as the preferred method for the treatment of calcaneal fractures. PMID:25550973

  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. Immunofluorescence Microscopy of Schizosaccharomyces pombe Using Chemical Fixation.

    PubMed

    Hagan, Iain M

    2016-01-01

    Establishing the subcellular distribution of molecules of interest and the dynamics of their spatial control underpins all areas of cell and developmental biology. Although the ability to monitor the distribution of fluorescent fusion proteins has revolutionized cell and developmental biology, indirect immunofluorescence microscopy of fixed samples remains an essential complement to this approach. Immunofluorescence is often a more appropriate approach for the study of subcellular architecture. It avoids potential artifacts caused by studying fusion proteins, which might show altered function under stressful imaging conditions. Furthermore, the quantitative analysis of multiple cells in an unperturbed population by immunofluorescence invariably provides a more accurate assessment of the spatial and temporal control of a particular process than does the analysis of individual cells that is the hallmark of live-cell imaging. Parallel studies of living and fixed cells often provide complementary data sets, both of which can be considered necessary for a comprehensive understanding of molecular function. This protocol provides a method for the visualization of the Schizosaccharomyces pombe microtubule cytoskeleton by indirect immunofluorescence microscopy following chemical fixation with formaldehyde and glutaraldehyde. It includes discussion of common modifications used to monitor the distribution of other fission yeast antigens and forms a basis from which to develop protocols to localize new molecules of interest. PMID:27371599

  1. Versatile microfluidic complement fixation test for disease biomarker detection.

    PubMed

    Li, Man; Shi, ZhuanZhuan; Fang, Can; Gao, AnXiu; Li, Chang Ming; Yu, Ling

    2016-04-15

    The complement fixation test (CFT) is a serological test that can be used to detect the presence of specific antibodies or antigens to diagnose infections, particularly diseases caused by microbes that are not easily detected by standard culture methods. We report here, for the first time, a poly(dimethylsiloxane) (PDMS)/glass slide hybrid microfluidic device that was used to manipulate the solution compartment and communication within the microchannel to establish sampler and indicator systems of CFT. Two types of on-chip CFT, solution-based and solid phase agar-based assays, were successfully demonstrated for biomarker carcinoembryonic antigen (CEA) and recombinant avian influenza A (rH7N9) virus protein detection. In addition, the feasibility of the on-chip CFT in assaying real biopsy was successfully demonstrated by specifically detecting rH7N9 and CEA in human serum. The results demonstrated that the miniaturized assay format significantly reduced the assay time and sample consumption. Exemption from protein immobilization, blocking, complicated washing steps and expensive enzyme/fluorescein conjugates highlights the merits of on-chip CFT over ELISA. Most attractively, the on-chip agar-based CFT results can be imaged and analysed by smartphone, strengthening its point-of-care application potential. We anticipate that the on-chip CFT reported herein will be a useful supplemental or back-up tool for on-chip immunoassays such as ELISA for disease diagnosis and food inspection. PMID:27016440

  2. Fixation method with high-orientation accuracy for optical terminals in space

    NASA Astrophysics Data System (ADS)

    Bauer, Dietrich; Lober, K.; Seeliger, Reinhard

    1991-12-01

    The LEO-Terminal of the ESA project SILEX (Semiconductor Intersateffite Link EXperiment) must provide a high pointing accuracy to be able to establish an optical inter orbit communication link. An alignment accuracy of 0.01° is required at the interface to the host satellite including the interface structure of the terminal to provide the necessary open loop pointing accuracy for acquisition of the counter terminal. Perturbations during launch, thermoelastic deformation and long term shrinking of the interface structure material CFRP are the determining sources of misalignment. The critical tilting of the interface structure can be reduced by means of slots for the fixation bolts, allowing translatoric movements at the interface fixation points in proper directions. Perpendicular movements to the selected direction (e.g. thermoelastic deformation and vibration during launch) must be strictly suppressed to avoid tilting in the plane of the attachment points at the interface satellite to terminal. Interface adapters at each connection will be used to overcome the problem of integrating the terminal with the tight toleranced fixation slots on the host satellite. One side of the adapters fixed to the terminal interface structure will provide the tight toleranced slots. The other side of the adapter will provide holes with sufficient large tolerances for the bolts used for the fixing of the terminal to the host satellite. These bolts are designed to fix the terminal rigidly under all environmental conditions by friction.

  3. 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

  4. Sporicidal activity of chemical and physical tissue fixation methods.

    PubMed Central

    Vardaxis, N J; Hoogeveen, M M; Boon, M E; Hair, C G

    1997-01-01

    AIMS: The effects of alcohol based fixation and microwave stimulated alcohol fixation were investigated on spores of Bacillus stearothermophilus and Bacillus subtilis (var. niger). METHODS: Spores were exposed to 10% formalin, or different concentrations of various alcohol containing fixatives (Kryofix/Spuitfix). Adequate controls were also set up in conjunction with the test solutions. The spores were immersed with and without adjunctive microwave stimulation in the various solutions tested. Possible surviving spores were recovered in revival broth and after incubation, and Gram staining viable counts were performed. RESULTS: Alcohol based fixatives did not have a sporicidal effect on B stearothermophilus or B subtilis (var. niger) spores, and microwave stimulated alcohol fixation at 450 W and up to 75 degrees C did not have a sporicidal effect. CONCLUSIONS: When alcohol based fixatives are used for fixation, precautions should be taken with the material thus treated, as it may contain viable spores or other pathogens, which are destroyed after 24 hours of formalin treatment. Of the physicochemical methods tested involving microwaving, none was successful in eliminating viable spores from the test material. PMID:9215128

  5. Regulation of Development and Nitrogen Fixation in Anabaena

    SciTech Connect

    James W. Golden

    2008-10-17

    The regulation of development and cellular differentiation is important for all multicellular organisms. The nitrogen-fixing filamentous cyanobacterium Anabaena (also Nostoc) sp. PCC 7120 (hereafter Anabaena) provides a model of multicellular microbial development and pattern formation. Anabaena reduces N2 to ammonia in specialized terminally differentiated cells called heterocysts. A one-dimensional developmental pattern of single heterocysts regularly spaced along filaments of photosynthetic vegetative cells is established to form a multicellular organism composed of these two interdependent cell types. This multicellular growth pattern, the distinct phylogeny of cyanobacteria, and the suspected antiquity of heterocyst development make this an important model system. Our long-term goal is to understand the regulatory network required for heterocyst development and nitrogen fixation. This project is focused on two key aspects of heterocyst regulation: one, the mechanism by which HetR controls the initiation of differentiation, and two, the cis and trans acting factors required for expression of the nitrogen-fixation (nif) genes. HetR is thought to be a central regulator of heterocyst development but the partners and mechanisms involved in this regulation are unknown. Our recent results indicate that PatS and other signals that regulate heterocyst pattern cannot interact, directly or indirectly, with a R223W mutant of HetR. We plan to use biochemical and genetic approaches to identify proteins that interact with the HetR protein, which will help reveal the mechanisms underlying its regulation of development. Our second goal is to determine how the nif genes are expressed. It is important to understand the mechanisms controlling nif genes since they represent the culmination of the differentiation process and the essence of heterocyst function. The Anabaena genome lacks the genes required for expression of nif genes present in other organisms such as rpoN (sigma 54

  6. Regulation of Development and Nitrogen Fixation in Anabaena

    SciTech Connect

    James W Golden

    2004-08-05

    The nitrogen-fixing filamentous cyanobacterium Anabaena sp. strain PCC 7120 is being used as a simple model of microbial development and pattern formation in a multicellular prokaryotic organism. Anabaena reduces atmospheric nitrogen to ammonia in highly specialized, terminally differentiated cells called heterocysts. Anabaena is an important model system because of the multicellular growth pattern, the suspected antiquity of heterocyst development, and the contribution of fixed nitrogen to the environment. We are especially interested in understanding the molecular signaling pathways and genetic regulation that control heterocyst development. In the presence of an external source of reduced nitrogen, the differentiation of heterocysts is inhibited. When Anabaena is grown on dinitrogen, a one-dimensional developmental pattern of single heterocysts separated by approximately ten vegetative cells is established to form a multicellular organism composed of two interdependent cell types. The goal of this project is to understand the signaling and regulatory pathways that commit a vegetative cell to terminally differentiate into a nitrogen-fixing heterocyst. Several genes identified by us and by others were chosen as entry points into the regulatory network. Our research, which was initially focused on transcriptional regulation by group 2 sigma factors, was expanded to include group 3 sigma factors and their regulators after the complete Anabaena genome sequence became available. Surprisingly, no individual sigma factor is essential for heterocyst development. We have used the isolation of extragenic suppressors to study genetic interactions between key regulatory genes such as patS, hetR, and hetC in signaling and developmental pathways. We identified a hetR R223W mutation as a bypass suppressor of patS overexpression. Strains containing the hetR R223W allele fail to respond to pattern formation signals and overexpression of this allele results in a lethal phenotype

  7. Pediatric anterior cruciate ligament femoral fixation: the trans-iliotibial band endoscopic portal for direct visualization of ideal button placement.

    PubMed

    Mistovich, R Justin; O'Toole, Patrick O J; Ganley, Theodore J

    2014-06-01

    Pediatric and adolescent anterior cruciate ligament reconstruction is a commonly performed procedure that has been increasing in incidence. Multiple techniques for graft fixation have been described. Button-based femoral cortical suspension fixation of the anterior cruciate ligament graft allows for fast, secure fixation with strong load-to-failure biomechanical properties. The biomechanical properties of button-based femoral cortical suspension fixation are especially beneficial with soft-tissue grafts such as hamstring autografts. Confirmation of a successfully flipped button can be achieved with intraoperative fluoroscopy or indirect viewing; however, these techniques do not provide direct visualization of the flipped button. Our trans-iliotibial band endoscopic portal allows the surgeon to safely and directly visualize the flipped button on the lateral femoral cortex and ensure that there is no malpositioning in the form of an incompletely flipped button or from soft-tissue interposition between the button and the lateral femoral cortex. This portal therefore allows for direct visual confirmation that the button is fully flipped and resting flush against the femoral cortex, deep to the iliotibial band and vastus lateralis.

  8. Fixation of proximal humeral prostheses and rotational micromotion.

    PubMed

    Harris, T E; Jobe, C M; Dai, Q G

    2000-01-01

    Twenty pairs of cadaveric humeri were used to compare the rotational stability of proximal humeral prostheses fixed by proximal cementation with the stability offered by press fit or full cementation. For each proximally cemented specimen, only the upper portion of the prosthesis was coated with cement. For the fully cemented specimens, a cement restrictor was used just distal to the prosthesis, and a finger-packing technique was used to fill the proximal humeral medullary canal. Torque was applied to the Morse taper of the prostheses, and rotational micromotion was measured at the level of the osteotomy. In each of 11 pairs of cadaveric humeri, one side was press fit and the contralateral side was proximally cemented; in each of 9 pairs, proximal cementation was compared with full cementation. Proximally cemented prostheses' micromotion was significantly less than that of press-fit prostheses (P = .0016). There was no difference in micromotion between proximal cementation and full cementation (P = .82). Proximal cementation increased initial fixation over press fit. Full cementation did not increase rotational stability.

  9. Photoactivated methods for enabling cartilage-to-cartilage tissue fixation

    NASA Astrophysics Data System (ADS)

    Sitterle, Valerie B.; Roberts, David W.

    2003-06-01

    The present study investigates whether photoactivated attachment of cartilage can provide a viable method for more effective repair of damaged articular surfaces by providing an alternative to sutures, barbs, or fibrin glues for initial fixation. Unlike artificial materials, biological constructs do not possess the initial strength for press-fitting and are instead sutured or pinned in place, typically inducing even more tissue trauma. A possible alternative involves the application of a photosensitive material, which is then photoactivated with a laser source to attach the implant and host tissues together in either a photothermal or photochemical process. The photothermal version of this method shows potential, but has been almost entirely applied to vascularized tissues. Cartilage, however, exhibits several characteristics that produce appreciable differences between applying and refining these techniques when compared to previous efforts involving vascularized tissues. Preliminary investigations involving photochemical photosensitizers based on singlet oxygen and electron transfer mechanisms are discussed, and characterization of the photodynamic effects on bulk collagen gels as a simplified model system using FTIR is performed. Previous efforts using photothermal welding applied to cartilaginous tissues are reviewed.

  10. Bilateral sacrospinous fixation without hysterectomy: 18-month follow-up

    PubMed Central

    Şentürk, Mehmet Baki; Güraslan, Hakan; Çakmak, Yusuf; Ekin, Murat

    2015-01-01

    Objective The aim of this study was to evaluate the results of bilateral sacrospinous fixation (SSF), which was performed with surgical mesh interposition and bilateral vaginal repair. Material and Methods Twenty-two patients underwent SSF between 2010 and 2012, and the results were evaluated retrospectively. The results at preoperative and postoperative 6th, 12th, and 18th months of the pelvic organ prolapse quantification system (POP-Q) and the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire-12 (PISQ-12) were compared using Friedman and Wilcoxon Signed Ranks tests. Values of p<0.05 and <0.01 were considered statistically significant. Results According to the POP-Q, significant healing was observed on all vaginal vault points (p=0.001), and no prolapse was observed until the 18-month follow-up stage. There were also prominent patients who felt satisfactory with respect to their sexual life according to PISQ-12 (p=0.001). Conclusion This technique appears to provide an adequate clinical resolution, and it may be the primary surgical option for women with pelvic organ prolapse. PMID:26097393

  11. Dark Fixation of CO2 by Crassulacean Plants

    PubMed Central

    Sutton, B. G.; Osmond, C. B.

    1972-01-01

    Malic acid isolated from Bryophyllum pinnatum (Lamk.) Oken (B. calycinum Salisb.), Bryophyllum tubiflorum Harv., Kalanchoë diagremontiana Hamet et Perrier and Sedum guatamalense Hemsl. after dark 14CO2 fixation was degraded by an in vitro NADP-malic enzyme technique. In the short term (5 to 30 seconds) the malic acid was almost exclusively labeled in the C-4 carboxyl carbon (greater than 90%). The percentage of 14C in the C-4 carboxyl of malic acid declined slowly with time, reaching 70% in B. tubiflorum and 54% in B. pinnatum after 14 hours of exposure to 14CO2. It was found that malic acid-adapted Lactobacillus arabinosus may seriously underestimate the C-4 carboxyl component of label in malic acid-14C. The amount of substrate which the bacteria can completely metabolize was easily exceeded; there was a significant level of randomization of label even when β-decarboxylation proceeded to completion, and in extended incubation periods, more than 25% of label was removed from malic acid-U-14C. The significance of these findings in relation to pathways of carbohydrate metabolism and malic acid synthesis in Crassulacean acid metabolism is discussed. PMID:16658174

  12. Fixation and chemical analysis of single fog and rain droplets

    NASA Astrophysics Data System (ADS)

    Kasahara, M.; Akashi, S.; Ma, C.-J.; Tohno, S.

    Last decade, the importance of global environmental problems has been recognized worldwide. Acid rain is one of the most important global environmental problems as well as the global warming. The grasp of physical and chemical properties of fog and rain droplets is essential to make clear the physical and chemical processes of acid rain and also their effects on forests, materials and ecosystems. We examined the physical and chemical properties of single fog and raindrops by applying fixation technique. The sampling method and treatment procedure to fix the liquid droplets as a solid particle were investigated. Small liquid particles like fog droplet could be easily fixed within few minutes by exposure to cyanoacrylate vapor. The large liquid particles like raindrops were also fixed successively, but some of them were not perfect. Freezing method was applied to fix the large raindrops. Frozen liquid particles existed stably by exposure to cyanoacrylate vapor after freezing. The particle size measurement and the elemental analysis of the fixed particle were performed in individual base using microscope, and SEX-EDX, particle-induced X-ray emission (PIXE) and micro-PIXE analyses, respectively. The concentration in raindrops was dependent upon the droplet size and the elapsed time from the beginning of rainfall.

  13. Fat Embolism Syndrome After Femur Fracture Fixation: a Case Report

    PubMed Central

    Akoh, Craig C; Schick, Cameron; Otero, Jesse; Karam, Matthew

    2014-01-01

    Fat embolism syndrome (FES) is a multi-organ disorder with potentially serious sequelae that is commonly seen in the orthopaedic patient population after femur fractures. The major clinical features of FES include hypoxia, pulmonary dysfunction, mental status changes, petechiae, tachycardia, fever, thrombocytopenia, and anemia. Due to technological advances in supportive care and intramedullary reaming techniques, the incidence of FES has been reported as low as 0.5 percent. Here, we present a rare case of FES with cerebral manifestations. A previously healthy 24-year old nonsmoking male was admitted to our hospital after an unrestrained head-on motor vehicle collision. The patient's injuries included a left olecranon fracture and closed bilateral comminuted midshaft femur fractures. The patient went on to develop cerebral fat embolism syndrome (CFES) twelve hours after immediate bilateral intramedullary nail fixation. His symptoms included unresponsiveness, disconjugate gaze, seizures, respiratory distress, fever, anemia, thrombocytopenia, and visual changes. Head computed tomography and brain magnetic resonance imaging showed pathognomonic white-matter punctate lesions and watershed involvement. With early recognition and supportive therapy and seizure therapy, the patient went on to have complete resolution of symptoms without cognitive sequelae. PMID:25328460

  14. Recovering of carbon fixation in a eucalyptus site after felling

    NASA Astrophysics Data System (ADS)

    Rodrigues, A. M.; Pita, G. P. A.; Mateus, A.; Santos Pereira, J.

    2009-04-01

    Espirra site (38°38'N,8°36'W) is located in a 300ha Eucalyptus globulus plantation, with a Mediterranean type climate with a mean annual precipitation of 709mm and a mean annual air temperature of 15.9°C. The plantation was established in 1986 with about 1100 trees ha-1. A 33m observation tower was installed in 2002, with an ultrasonic Gill anemometer R2, an open path analyzer IRGA LI-7500 and a microclimate unit at its top. A harvesting of trees was made at the end of the 2nd rotation period, from November to December 2006. During the last four years of the second rotation the coppice were 20m height. Harvesting was planned in order to initiate a new 12 year productive cycle. In October 2008 a first thinning was made in three fourths of emerging stems from stumps. At this stage the forest trees had a mean height of 6m. For the 2002-2006 period, mean annual values of carbon net ecosystem exchange (NEE), gross production(GPP) and ecosystem respiration(Reco) were -533.3 gCm-2, 1628.6 gCm-2 and 1095.2 gCm-2. Seasonal patterns of carbon fixation for the five years showed a decrease in July-August periods due to highest air temperatures, atmospheric water vapour deficits and stomata partial closure to prevent water transpiration losses. For the period 2002-2006, the dry year of 2005 with a precipitation of about 390 mm, corresponded to the smaller carbon fixation of 390 gCm-2. Similarly, values of Reco, GPP and estimated leaf area index (less than three) were also minimal in 2005. Water use efficiency, WUE (ratio GPP/precipitation) was maximum in summer periods and in driest years, reaching values of about 12g/L-1. Recovery of carbon sink capacity, after the felling, begun after August 2007. The 2007 and 2008 annual NEE values were respectively 105.8 gCm-2 and -35.78 gCm-2. This negative value of NEE for 2008 is indicative of a carbon sink recovery. Annual Reco values for 2007 and 2008 were respectively 1059.03 gCm-2 and 1148.21 gCm-2. For GPP the annual values of

  15. 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

  16. Pupil size dynamics during fixation impact the accuracy and precision of video-based gaze estimation.

    PubMed

    Choe, Kyoung Whan; Blake, Randolph; Lee, Sang-Hun

    2016-01-01

    Video-based eye tracking relies on locating pupil center to measure gaze positions. Although widely used, the technique is known to generate spurious gaze position shifts up to several degrees in visual angle because pupil centration can change without eye movement during pupil constriction or dilation. Since pupil size can fluctuate markedly from moment to moment, reflecting arousal state and cognitive processing during human behavioral and neuroimaging experiments, the pupil size artifact is prevalent and thus weakens the quality of the video-based eye tracking measurements reliant on small fixational eye movements. Moreover, the artifact may lead to erroneous conclusions if the spurious signal is taken as an actual eye movement. Here, we measured pupil size and gaze position from 23 human observers performing a fixation task and examined the relationship between these two measures. Results disclosed that the pupils contracted as fixation was prolonged, at both small (<16s) and large (∼4min) time scales, and these pupil contractions were accompanied by systematic errors in gaze position estimation, in both the ellipse and the centroid methods of pupil tracking. When pupil size was regressed out, the accuracy and reliability of gaze position measurements were substantially improved, enabling differentiation of 0.1° difference in eye position. We confirmed the presence of systematic changes in pupil size, again at both small and large scales, and its tight relationship with gaze position estimates when observers were engaged in a demanding visual discrimination task.

  17. Pupil size dynamics during fixation impact the accuracy and precision of video-based gaze estimation.

    PubMed

    Choe, Kyoung Whan; Blake, Randolph; Lee, Sang-Hun

    2016-01-01

    Video-based eye tracking relies on locating pupil center to measure gaze positions. Although widely used, the technique is known to generate spurious gaze position shifts up to several degrees in visual angle because pupil centration can change without eye movement during pupil constriction or dilation. Since pupil size can fluctuate markedly from moment to moment, reflecting arousal state and cognitive processing during human behavioral and neuroimaging experiments, the pupil size artifact is prevalent and thus weakens the quality of the video-based eye tracking measurements reliant on small fixational eye movements. Moreover, the artifact may lead to erroneous conclusions if the spurious signal is taken as an actual eye movement. Here, we measured pupil size and gaze position from 23 human observers performing a fixation task and examined the relationship between these two measures. Results disclosed that the pupils contracted as fixation was prolonged, at both small (<16s) and large (∼4min) time scales, and these pupil contractions were accompanied by systematic errors in gaze position estimation, in both the ellipse and the centroid methods of pupil tracking. When pupil size was regressed out, the accuracy and reliability of gaze position measurements were substantially improved, enabling differentiation of 0.1° difference in eye position. We confirmed the presence of systematic changes in pupil size, again at both small and large scales, and its tight relationship with gaze position estimates when observers were engaged in a demanding visual discrimination task. PMID:25578924

  18. Pitfalls during biomechanical testing - Evaluation of different fixation methods for measuring tendons endurance properties.

    PubMed

    Hangody, Gy; Pánics, G; Szebényi, G; Kiss, R; Hangody, L; Pap, K

    2016-03-01

    The goal of the study was to find a proper technique to fix tendon grafts into an INSTRON loading machine. From 8 human cadavers, 40 grafts were collected. We removed the bone-patella tendon-bone grafts, the semitendinosus and gracilis tendons, the quadriceps tendon-bone grafts, the Achilles tendons, and the peroneus longus tendons from each lower extremity. We tested the tendon grafts with five different types of fixation devices: surgical thread (Premicron 3), general mounting clamp, wire mesh, cement fixation, and a modified clamp for an INSTRON loading machine. The mean failure load in case of surgical thread fixation was (381N ± 26N). The results with the general clamp were (527N ± 45N). The wire meshes were more promising (750N ± 21N), but did not reach the outcomes we desired. Easy slippages of the ends of the tendons from the cement encasements were observed (253N ± 18N). We then began to use Shi's clamp that could produce 977N ± 416N peak force. We combined Shi's clamp with freezing of the graft and the rupture of the tendon itself demonstrated an average force of 2198 N ± 773N. We determined that our modified frozen clamp fixed the specimens against high tensile forces.

  19. Influence of cementless cup surface on stability and bone fixation 2 years after total hip arthroplasty.

    PubMed

    Urbański, Wiktor; Krawczyk, Artur; Dragan, Szymon Ł; Kulej, Mirosław; Dragan, Szymon F

    2012-01-01

    Loss of fixation between bone and implant surface is one of the main treatment problems in total hip arthroplasty. It might lead to implant instability, bone loss and treatment failure resulting in revision surgery. Surface modification is a method for improving bone response to implant and increasing implant osseointegration. However, the currently applied modifications such as hydroxyapatite coatings do not meet expectation and do not provide good clinical result. The object of the study was to evaluate the influence of acetabular cup surface modification on fixation and bone remodelling in total hip arthroplasty. Clinical and radiological outcomes were evaluated in patients two years after cementless total hip replacement. Two groups were compared: patients with acetabular component with uncoated titanium surface and patients with hydroxyapatite-coated acetabular surface. Hips X-rays were analysed for early signs of losing stability of acetabular cups. Two years after surgery the analysis of X-rays did not reveal any statistical differences in stability, migration of acetabular components of endoprosthesis between both groups. No differences were also observed in bone remodelling around implants. Particularly high percentage of cups, i.e. 17.64%, were classified into the group with high risk of early implant loosening, i.e., the group with HA coatings. Hydroxyapatite coatings on titanium cementless acetabular cups implanted by press-fit technique have no influence on their stability, bone-implant fixation and the remodelling of bone surrounding an implant two years after surgery.

  20. The reverse abdominal reduction and the 'waistcoating' procedure for the correction of the fixated Pfannenstiel incision.

    PubMed

    Harrison, Douglas H

    2016-05-01

    The principles of a standard abdominal reduction are well understood; this technique has been used for many years. However, a reverse abdominal reduction may be considered in some cases, for example, continued weight loss, and thus skin redundancy on the upper abdomen in patients who have already undergone abdominal reduction and upper abdomen improvement in patients requiring a mastopexy or breast reduction simultaneously. Reverse abdominal reduction is rarely mentioned in the medical literature, but it can prove successful; although the scar across the lower sternum has often been considered to be unsatisfactory, often it does not prove to be so. Thus, this procedure can be proven to be successful in suitable cases. Secondly, the Pfannenstiel incision, if not satisfactorily repaired in the first instance, can become fixated to the abdominal wall; this fixation along with the inevitable migration of skin and fat at its cephalic edge causes a rather displeasing contour defect when wearing tight-fitting swimwear. The principle of the waistcoating procedure is essentially to chamfer the fat cephalically; this procedure is employed for removing the Pfannenstiel scar from the abdominal wall. The principle is simple and effective and can be applied in cases with fixated scars. These two aforementioned principles are not commonly used, but they can prove particularly effective in suitable cases. We illustrate the principles. PMID:26966077

  1. The reverse abdominal reduction and the 'waistcoating' procedure for the correction of the fixated Pfannenstiel incision.

    PubMed

    Harrison, Douglas H

    2016-05-01

    The principles of a standard abdominal reduction are well understood; this technique has been used for many years. However, a reverse abdominal reduction may be considered in some cases, for example, continued weight loss, and thus skin redundancy on the upper abdomen in patients who have already undergone abdominal reduction and upper abdomen improvement in patients requiring a mastopexy or breast reduction simultaneously. Reverse abdominal reduction is rarely mentioned in the medical literature, but it can prove successful; although the scar across the lower sternum has often been considered to be unsatisfactory, often it does not prove to be so. Thus, this procedure can be proven to be successful in suitable cases. Secondly, the Pfannenstiel incision, if not satisfactorily repaired in the first instance, can become fixated to the abdominal wall; this fixation along with the inevitable migration of skin and fat at its cephalic edge causes a rather displeasing contour defect when wearing tight-fitting swimwear. The principle of the waistcoating procedure is essentially to chamfer the fat cephalically; this procedure is employed for removing the Pfannenstiel scar from the abdominal wall. The principle is simple and effective and can be applied in cases with fixated scars. These two aforementioned principles are not commonly used, but they can prove particularly effective in suitable cases. We illustrate the principles.

  2. Osteosynthesis in Distal Radius Fractures with Conventional Bridging External Fixator; Tips and Tricks for Getting Them Right

    PubMed Central

    Chilakamary, Vamshi Krishna; Koppolu, Kiran Kumar; Rapur, Shivaprasad

    2016-01-01

    Background Distal radius fractures are the commonest fractures occurring in the upper extremity, accounting for 15-20% of patients treated in emergency department. Although distal radial fractures were described 200 years ago, they still remain as unsolved fractures with no clear guidelines. It is often reported that anatomical reduction has a bearing on the functional outcome. Aim To study the management of distal end radius fracture by utilizing the principle of ligamentotaxis where in the reduction obtained by closed means is maintained by external fixator till solid bony union occurs. Materials and Methods A total of 26 cases were selected for study by scrutiny of the inclusion and exclusion criteria. Most of our cases were treated with external fixator within 8 hrs of injury. Small A.O external fixator (bridging ex-fix) with 2 pins each in radius and 2nd metacarpal percutaneously was used for all the cases. Selective k wire fixation was done in cases of instability. Fixator was removed after 6 weeks. Guided physiotherapy was ensured in all the cases. Patients were followed up for an average of 9 months. Results Modified Gartland and Werley scoring system was used to evaluate the overall functional results. Excellent to good results were achieved in 88.45% of our cases while fair result was in 11.54 %. One case had pin loosening and two other cases had malunion. Conclusion External fixator used for ligamentotaxis is an effective method of treating unstable extraarticular and complex intraarticular fractures of distal radius. Improved anatomical restoration with early rehabilitation has produced favourable functional outcome in our series. The complications like pin tract infection is rare due to the availability of superior antibiotics and sterile surgical technique. complications like wrist and finger stiffness has improved with physiotherapy. PMID:26894133

  3. The Glubran 2 glue for mesh fixation in Lichtenstein's hernia repair: a double-blind randomized study

    PubMed Central

    Dąbrowiecki, Stanisław; Pierściński, Stanisław

    2012-01-01

    Introduction With an average incidence rate of 11%, chronic pain is considered the most serious complication of inguinal hernioplasty after surgical site infection. One of the proposed solutions to this problem is to use tissue adhesive for mesh fixation, which helps prevent nerve and tissue damage. Aim The goal of this study was to compare mesh fixation with the use of sutures vs. adhesive in Lichtenstein's inguinal hernia repair in a randomized, double-blind one-center study. Material and methods The study group consisted of 41 males with primary inguinal hernia undergoing Lichtenstein's repair (20 – adhesive; 21 – suture) and remaining in follow-up from July 2008 to November 2010. Randomization took place during the operation. The follow-up was performed by one surgeon (blinded) according to a pre-agreed schedule; the end-of-study unblinding was performed during the last follow-up visit, usually 16 months postoperatively. Results In 1 patient from the “adhesive” group, a recurrence was observed one year after the initial repair. The early postoperative pain was less intense in this group. In later postoperative periods the method of mesh fixation had no influence on the pain experienced by the patient. Other complications were not correlated with the method of mesh fixation. Conclusions In this randomized, one-center double-blind clinical study of males with primary inguinal hernia it has been show during follow-up that the use of Glubran 2 cyanoacrylate adhesive for mesh implant fixation yields similar recurrence and chronic pain rates as the classical suture technique. In the early postoperative period, the pain reported by these patients was relatively weaker; patients undergoing adhesive mesh fixation experienced a quicker return to daily household activities. PMID:23256009

  4. Novel retrograde puncture method to establish preperitoneal space for laparoscopic direct inguinal hernia repair with internal ring suturing

    PubMed Central

    Jiang, H.; Ma, R.; Zhang, X.

    2016-01-01

    The aim of this study was to explore the clinical efficacy of a novel retrograde puncture approach to establish a preperitoneal space for laparoscopic direct inguinal hernia repair with inguinal ring suturing. Forty-two patients who underwent laparoscopic inguinal hernia repair with retrograde puncture for preperitoneal space establishment as well as inguinal ring suturing between August 2013 and March 2014 at our hospital were enrolled. Preperitoneal space was successfully established in all patients, with a mean establishment time of 6 min. Laparoscopic repairs were successful in all patients, with a mean surgical time of 26±15.1 min. Mean postoperative hospitalization duration was 3.0±0.7 days. Two patients suffered from postoperative local hematomas, which were relieved after puncturing and drainage. Four patients had short-term local pain. There were no cases of chronic pain. Patients were followed up for 6 months to 1 year, and no recurrence was observed. Our results demonstrate that preperitoneal space established by the retrograde puncture technique can be successfully used in adult laparoscopic hernioplasty to avoid intraoperative mesh fixation, and thus reduce medical costs. PMID:27191609

  5. The advantages of combining sonotopogram with indication and fixation in invasive ultrasound.

    PubMed

    Pilecki, Zbigniew; Pilecki, Grzegorz; Ciekalski, Jacek; Dzielicki, Józef; Jakubowski, Wiesław

    2012-09-01

    The usefulness of sonotopogram, that is mapping of the operated area basing on ultrasound, is obvious and currently unquestionable. It is performed in order to improve safety level of a patient treated by means of invasive techniques. It constitutes an excellent complement of the Perioperative Control Card. At the beginning it was used in sonosurgical procedures, with time it has become an element of all surgical techniques. It undergoes multiple changes depending on the surgeon's needs. A particularly interesting phenomenon is the combination of the invasive techniques in order to facilitate the performance of medical procedures. Because of some relationship we are going to present the combination of sonotopogram with fixation and indication techniques. They are puncture techniques which are relatively rarely used in invasive ultrasound and surgical procedures. It seems that this results from the ignorance of their potential and the technique of their performance. Great simplicity makes them universal and allows to combine them freely. This simple combinations can be extended practically endlessly - similarly to domino bricks. For example, the next element of the technique combining can be the removal of an indicated and fixated element or a nailing. It is an excellent example of the complementarity rule - it should facilitate the understanding of Allin1 techniques and sonosurgery and also help in everyday practice of doctors performing invasive procedures. The use of these methods should be propagated not only in ultrasound but also in everyday medical practice in all the specialties. The presentation of the examples of particular techniques and their combination enables to bring closer their practical use.

  6. Tibial Fixation Properties of a Continuous-Loop ACL Hamstring Graft Construct with Suspensory Fixation in Porcine Bone.

    PubMed

    Smith, Patrick A; DeBerardino, Thomas M

    2015-12-01

    The aim of this article is to compare tibial fixation strength of suspensory fixation for a quadrupled semitendinosus continuous loop all-inside anterior cruciate ligament (ACL) construct versus a doubled semitendinosus and gracilis graft fixated with an interference screw. Biomechanical testing was conducted using human hamstring allografts and porcine tibias. Constructs were cycled from 50 to 250 N for 500 cycles followed by a pull to failure. The average load to failure of tibial suspensory fixation of the all-inside continuous loop construct (1,012 N) was statistically different compared with the tibial interference screw group (612 N) (p < 0.001). The cyclic displacement of the continuous loop construct (2.5 mm) was not statistically different from the interference screw construct (1.9 mm). For both the groups, approximately half the overall cyclic displacement occurred with the first cycle. Tibial side suspensory fixation of a novel all-inside continuous loop hamstring graft provided suitable strength for tibial fixation for ACL reconstruction. The continuous loop construct had a significantly higher load to failure compared with the use of an interference screw, and cyclic loading was comparable. Use of hamstring soft tissue grafts is very common for ACL reconstruction. An all-inside ACL reconstruction is based on a continuous loop construct utilizing a single semitendinosus graft that is quadrupled employing suspensory fixation on both the femoral and tibial side. Suspensory fixation on the femoral side been previously reported, but this is the first report of strength of this method of suspensory fixation on the tibia. PMID:25347056

  7. Minimally Invasive Mini Open Split-Muscular Percutaneous Pedicle Screw Fixation of the Thoracolumbar Spine

    PubMed Central

    Ulutaş, Murat; Seçer, Mehmet; Çelik, Suat Erol

    2015-01-01

    We prospectively assessed the feasibility and safety of a new percutaneous pedicle screw (PPS) fixation technique for instrumentation of the thoracic and lumbar spine in this study. All patients were operated in the prone position under general anesthesia. A 6 to 8 cm midline skin incision was made and wide subcutaneous dissection was performed. The paravertebral muscles were first dissected subperiosteally into the midline incision of the fascia for lumbar microdiscectomy with transforaminal lumbar interbody fusion cage implantation. After the secondary paramedian incisions on the fascia, the PPSs were inserted via cleavage of the multifidus muscles directly into the pedicles under fluoroscopy visualization. A total of 35 patients underwent surgery with this new surgical technique. The control group for operative time, blood loss and analgesic usage consisted of 35 randomly selected cases from our department. The control group underwent surgery via conventional pedicle screw instrumentation with paramedian fusion. All patients in the minimal invasive surgery series were ambulatory with minimal pain on the first postoperative day. The operation time and blood loss and the postoperative analgesic consumption were significantly less with this new technique. In conclusion, the minimal invasive mini open split-muscular percutaneous pedicle screw fixation technique is safe and feasible. It can be performed via a short midline skin incision and can also be combined with interbody fusion, causing minimal pain without severe muscle damage. PMID:25874062

  8. Minimally invasive mini open split-muscular percutaneous pedicle screw fixation of the thoracolumbar spine.

    PubMed

    Ulutaş, Murat; Seçer, Mehmet; Çelik, Suat Erol

    2015-03-01

    We prospectively assessed the feasibility and safety of a new percutaneous pedicle screw (PPS) fixation technique for instrumentation of the thoracic and lumbar spine in this study. All patients were operated in the prone position under general anesthesia. A 6 to 8 cm midline skin incision was made and wide subcutaneous dissection was performed. The paravertebral muscles were first dissected subperiosteally into the midline incision of the fascia for lumbar microdiscectomy with transforaminal lumbar interbody fusion cage implantation. After the secondary paramedian incisions on the fascia, the PPSs were inserted via cleavage of the multifidus muscles directly into the pedicles under fluoroscopy visualization. A total of 35 patients underwent surgery with this new surgical technique. The control group for operative time, blood loss and analgesic usage consisted of 35 randomly selected cases from our department. The control group underwent surgery via conventional pedicle screw instrumentation with paramedian fusion. All patients in the minimal invasive surgery series were ambulatory with minimal pain on the first postoperative day. The operation time and blood loss and the postoperative analgesic consumption were significantly less with this new technique. In conclusion, the minimal invasive mini open split-muscular percutaneous pedicle screw fixation technique is safe and feasible. It can be performed via a short midline skin incision and can also be combined with interbody fusion, causing minimal pain without severe muscle damage. PMID:25874062

  9. Decision-making in information seeking on texts: an eye-fixation-related potentials investigation.

    PubMed

    Frey, Aline; Ionescu, Gelu; Lemaire, Benoit; López-Orozco, Francisco; Baccino, Thierry; Guérin-Dugué, Anne

    2013-01-01

    Reading on a web page is known to be not linear and people need to make fast decisions about whether they have to stop or not reading. In such context, reading, and decision-making processes are intertwined and this experiment attempts to separate them through electrophysiological patterns provided by the Eye-Fixation-Related Potentials technique (EFRPs). We conducted an experiment in which EFRPs were recorded while participants read blocks of text that were semantically highly related, moderately related, and unrelated to a given goal. Participants had to decide as fast as possible whether the text was related or not to the semantic goal given at a prior stage. Decision making (stopping information search) may occur when the paragraph is highly related to the goal (positive decision) or when it is unrelated to the goal (negative decision). EFRPs were analyzed on and around typical eye fixations: either on words belonging to the goal (target), subjected to a high rate of positive decisions, or on low frequency unrelated words (incongruent), subjected to a high rate of negative decisions. In both cases, we found EFRPs specific patterns (amplitude peaking between 51 to 120 ms after fixation onset) spreading out on the next words following the goal word and the second fixation after an incongruent word, in parietal and occipital areas. We interpreted these results as delayed late components (P3b and N400), reflecting the decision to stop information searching. Indeed, we show a clear spill-over effect showing that the effect on word N spread out on word N + 1 and N + 2.

  10. Decision-making in information seeking on texts: an eye-fixation-related potentials investigation

    PubMed Central

    Frey, Aline; Ionescu, Gelu; Lemaire, Benoit; López-Orozco, Francisco; Baccino, Thierry; Guérin-Dugué, Anne

    2013-01-01

    Reading on a web page is known to be not linear and people need to make fast decisions about whether they have to stop or not reading. In such context, reading, and decision-making processes are intertwined and this experiment attempts to separate them through electrophysiological patterns provided by the Eye-Fixation-Related Potentials technique (EFRPs). We conducted an experiment in which EFRPs were recorded while participants read blocks of text that were semantically highly related, moderately related, and unrelated to a given goal. Participants had to decide as fast as possible whether the text was related or not to the semantic goal given at a prior stage. Decision making (stopping information search) may occur when the paragraph is highly related to the goal (positive decision) or when it is unrelated to the goal (negative decision). EFRPs were analyzed on and around typical eye fixations: either on words belonging to the goal (target), subjected to a high rate of positive decisions, or on low frequency unrelated words (incongruent), subjected to a high rate of negative decisions. In both cases, we found EFRPs specific patterns (amplitude peaking between 51 to 120 ms after fixation onset) spreading out on the next words following the goal word and the second fixation after an incongruent word, in parietal and occipital areas. We interpreted these results as delayed late components (P3b and N400), reflecting the decision to stop information searching. Indeed, we show a clear spill-over effect showing that the effect on word N spread out on word N + 1 and N + 2. PMID:23966913

  11. Biomechanical optimization of different fixation modes for a proximal femoral L-osteotomy

    PubMed Central

    Tai, Ching-Lung; Chen, Weng-Pin; Chen, Hsih-Hao; Lin, Chien-Yu; Lee, Mel S

    2009-01-01

    Background Numerous proposed surgical techniques have had minimal success in managing greater trochanter overgrowth secondary to retarded growth of the femoral capital epiphysis. For reconstruction of residual hip deformities, a novel type of proximal femur L-osteotomy was performed with satisfactory results. Although the clinical outcome was good, the biomechanical characteristics of the femur after such an osteotomy have not been clearly elucidated. Therefore, this study presents a three dimensional finite element analysis designed to understand the mechanical characteristics of the femur after the L-osteotomy. Methods A patient with left hip dysplasia was recruited as the study model for L-osteotomy. The normal right hip was used as a reference for performing the corrective surgery. Four FEA models were constructed using different numbers of fixation screws but the same osteotomy lengths together with four FEA models with the same number of fixation screws but different osteotomy lengths. The von Mises stress distributions and femoral head displacements were analyzed and compared. Results The results revealed the following: 1). The fixation devices (plate and screws) sustained most of the external loading, and the peak value of von Mises stress on the fixation screws decreased with an increasing number of screws. 2). Additional screws are more beneficial on the proximal segment than on the distal segment for improving the stability of the postoperative femur. 3). The extent of osteotomy should be limited because local stress might be concentrated in the femoral neck region with increasing length of the L-osteotomy. Conclusion Additional screw placement on the proximal segment improves stability in the postoperative femur. The cobra-type plate with additional screw holes in the proximal area might improve the effectiveness of L-osteotomies. PMID:19744345

  12. Early open reduction and internal fixation of the disrupted pelvic ring.

    PubMed

    Goldstein, A; Phillips, T; Sclafani, S J; Scalea, T; Duncan, A; Goldstein, J; Panetta, T; Shaftan, G

    1986-04-01

    Early open reduction and internal fixation (ORIF) of extremity fractures in patients with multiple injuries has been demonstrated to be safe, improve survival, and decrease the incidence of respiratory failure. Complications leading to abandonment of planned operative fixation and death in several patients with pelvic fractures led us to initiate a policy of early ORIF of the disrupted pelvic ring. Early ORIF of the pelvis was performed in 15 multiply injured patients between May 1984 and August 1985. Patients ranged in age from 13 to 79 years, their Hospital Trauma Index-ISS scores ranged from 14 to 68, and number of preoperative transfusions ranged from 0 to 42. Types of fractures were A-P compression, two, lateral compression, one, vertical shear, seven, complex, two, and acetabulum with ring disruption, three. All patients were resuscitated, transported in pneumatic antishock garments, and evaluated by abdominal and pelvic CT scan (in two patients following celiotomy). Preoperative angiograms to assess retroperitoneal hemorrhage in eight patients resulted in identification and control of significant bleeding in five. The mean time from injury to pelvic stabilization was 38 hours. Seven patients underwent ORIF within the first 24 hours. In most cases simultaneous anterior and posterior internal fixation was performed with the patient in the lateral decubitus position. Excluding associated procedures, operative time averaged 5.1 hours. Intra-operative transfusions averaged 4 units (range, 0-11). Rigid fixation was achieved in all patients. Most patients were out of bed by the third postoperative day. No patient developed respiratory failure. Two patients developed wound infections. Modification of our technique has avoided this complication in the latter part of this series.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Integration and Fixation Preferences of Human and Mouse Endogenous Retroviruses Uncovered with Functional Data Analysis

    PubMed Central

    Pini, Alessia; Chiaromonte, Francesca; Makova, Kateryna D.

    2016-01-01

    Endogenous retroviruses (ERVs), the remnants of retroviral infections in the germ line, occupy ~8% and ~10% of the human and mouse genomes, respectively, and affect their structure, evolution, and function. Yet we still have a limited understanding of how the genomic landscape influences integration and fixation of ERVs. Here we conducted a genome-wide study of the most recently active ERVs in the human and mouse genome. We investigated 826 fixed and 1,065 in vitro HERV-Ks in human, and 1,624 fixed and 242 polymorphic ETns, as well as 3,964 fixed and 1,986 polymorphic IAPs, in mouse. We quantitated >40 human and mouse genomic features (e.g., non-B DNA structure, recombination rates, and histone modifications) in ±32 kb of these ERVs’ integration sites and in control regions, and analyzed them using Functional Data Analysis (FDA) methodology. In one of the first applications of FDA in genomics, we identified genomic scales and locations at which these features display their influence, and how they work in concert, to provide signals essential for integration and fixation of ERVs. The investigation of ERVs of different evolutionary ages (young in vitro and polymorphic ERVs, older fixed ERVs) allowed us to disentangle integration vs. fixation preferences. As a result of these analyses, we built a comprehensive model explaining the uneven distribution of ERVs along the genome. We found that ERVs integrate in late-replicating AT-rich regions with abundant microsatellites, mirror repeats, and repressive histone marks. Regions favoring fixation are depleted of genes and evolutionarily conserved elements, and have low recombination rates, reflecting the effects of purifying selection and ectopic recombination removing ERVs from the genome. In addition to providing these biological insights, our study demonstrates the power of exploiting multiple scales and localization with FDA. These powerful techniques are expected to be applicable to many other genomic investigations

  14. Experimental and Numerical Analysis of Screw Fixation in Anterior Cruciate Ligament Reconstruction

    NASA Astrophysics Data System (ADS)

    Chizari, Mahmoud; Wang, Bin; Snow, Martyn; Barrett, Mel

    2008-09-01

    This paper reports the results of an experimental and finite element analysis of tibial screw fixation in anterior cruciate ligament (ACL) reconstruction. The mechanical properties of the bone and tendon graft are obtained from experiments using porcine bone and bovine tendon. The results of the numerical study are compared with those from mechanical testing. Analysis shows that the model may be used to establish the optimum placement of the tunnel in anterior cruciate ligament reconstruction by predicting mechanical parameters such as stress, strain and displacement at regions in the tunnel wall.

  15. The Role of Personality and Team-Based Product Dissection on Fixation Effects

    ERIC Educational Resources Information Center

    Toh, Christine; Miller, Scarlett; Kremer, Gül E. Okudan

    2013-01-01

    Design fixation has been found to be complex in its definition and expression, but it plays an important role in design idea generation. Identifying the factors that influence fixation is crucial in understanding how to enhance the design process and reduce the negative effects of fixation. One way to potentially mitigate fixation is through…

  16. Fixation of tritium in a highly stable polymer form

    DOEpatents

    Steinberg, Meyer; Colombo, Peter; Pruzansky, Jacob

    1977-01-01

    A method for the fixation of tritium comprising reacting tritiated water with calcium carbide to produce calcium hydroxide and tritiated acetylene, polymerizing the acetylene, and then incorporating the polymer in a solidifying matrix.

  17. Eye Position Changes during Reading Fixations are Spatially Selective

    PubMed Central

    Inhoff, Albrecht W.; Solomon, Matthew S.; Seymour, Bradley A.; Radach, Ralph

    2008-01-01

    Intra-fixation location changes were measured when one-line sentences written in lower or aLtErNaTiNg case were read. Intra-fixation location changes were common and their size was normally distributed except for a relatively high proportion of fixations without a discernible location change. Location changes that did occur were systematically biased toward the right when alternating case was read. Irrespective of case type, changes of the right eye were biased toward the right at the onset of sentence reading, and this spatial bias decreased as sentence reading progressed from left to right. The left eye showed a relatively stable right-directed bias. These results show that processing demands can pull the two fixated eyes in the same direction and that the response to this pull can differ for the right and left eye. PMID:18313717

  18. Light response of nitrogen fixation in Lake Valencia, Venezuela

    SciTech Connect

    Lewis, W.M. Jr.; Levine, S.N.

    1984-07-01

    Water samples from six depths in the upper water column of Lake Valencia, Venezuela, were incubated in situ with acetylene at several depths corresponding to different light exposures. On five dates there was sufficient nitrogen fixation to define the light-response curve for samples taken at 2 and 100 cm. The light response of nitrogen fixation was modeled successfully with an equation previously developed for the light response of photosynthesis. All parameter values of the response curves for samples originating at a given depth were relatively stable across dates, but differed between depths. Rates of increase of N fixation with irradiance in the subsaturation range (..cap alpha..) were much lower than is typical of photosynthesis. While the general shape of nitrogen fixation curves was similar to that of photosynthesis curves, critical parameters were more sensitive to the light history (depth of origin) of cells than would be expected for photosynthesis.

  19. Fixation systems of greater trochanteric osteotomies: biomechanical and clinical outcomes.

    PubMed

    Jarit, Gregg J; Sathappan, Sathappan S; Panchal, Anand; Strauss, Eric; Di Cesare, Paul E

    2007-10-01

    The development of cerclage systems for fixation of greater trochanteric osteotomies has progressed from monofilament wires to multifilament cables to cable grip and cable plate systems. Cerclage wires and cables have various clinical indications, including fixation for fractures and for trochanteric osteotomy in hip arthroplasty. To achieve stable fixation and eventual union of the trochanteric osteotomy, the implant must counteract the destabilizing forces associated with pull of the peritrochanteric musculature. The material properties of cables and cable grip systems are superior to those of monofilament wires; however, potential complications with the use of cables include debris generation and third-body polyethylene wear. Nevertheless, the cable grip system provides the strongest fixation and results in lower rates of nonunion and trochanteric migration. Cable plate constructs show promise but require further clinical studies to validate their efficacy and safety.

  20. Eye position changes during reading fixations are spatially selective.

    PubMed

    Inhoff, Albrecht W; Solomon, Matthew S; Seymour, Bradley A; Radach, Ralph

    2008-03-01

    Intra-fixation location changes were measured when one-line sentences written in lower or aLtErNaTiNg case were read. Intra-fixation location changes were common and their size was normally distributed except for a relatively high proportion of fixations without a discernible location change. Location changes that did occur were systematically biased toward the right when alternating case was read. Irrespective of case type, changes of the right eye were biased toward the right at the onset of sentence reading, and this spatial bias decreased as sentence reading progressed from left to right. The left eye showed a relatively stable right-directed bias. These results show that processing demands can pull the two fixated eyes in the same direction and that the response to this pull can differ for the right and left eye.