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Sample records for double bundle anterior

  1. A Comparison between Clinical Results of Selective Bundle and Double Bundle Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Yoo, Yon-Sik; Song, Si Young; Yang, Cheol Jung; Ha, Jong Mun; Kim, Yoon Sang

    2016-01-01

    Purpose The purpose of this study was to compare the clinical outcomes of arthroscopic anatomical double bundle (DB) anterior cruciate ligament (ACL) reconstruction with either selective anteromedial (AM) or posterolateral (PL) bundle reconstruction while preserving a relatively healthy ACL bundle. Materials and Methods The authors evaluated 98 patients with a mean follow-up of 30.8±4.0 months who had undergone DB or selective bundle ACL reconstructions. Of these, 34 cases underwent DB ACL reconstruction (group A), 34 underwent selective AM bundle reconstruction (group B), and 30 underwent selective PL bundle reconstructions (group C). These groups were compared with respect to Lysholm and International Knee Documentation Committee (IKDC) score, side-to-side differences of anterior laxity measured by KT-2000 arthrometer at 30 lbs, and stress radiography and Lachman and pivot shift test results. Pre- and post-operative data were objectively evaluated using a statistical approach. Results The preoperative anterior instability measured by manual stress radiography at 90° of knee flexion in group A was significantly greater than that in groups B and C (all p<0.001). At last follow-up, mean side-to-side instrumented laxities measured by the KT-2000 and manual stress radiography were significantly improved from preoperative data in all groups (all p<0.001). There were no significant differences between the three groups in anterior instability measured by KT-2000 arthrometer, pivot shift, or functional scores. Conclusion Selective bundle reconstruction in partial ACL tears offers comparable clinical results to DB reconstruction in complete ACL tears. PMID:27401652

  2. ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION USING THE DOUBLE-BUNDLE TECHNIQUE – EVALUATION IN THE BIOMECHANICS LABORATORY

    PubMed Central

    D'Elia, Caio Oliveira; Bitar, Alexandre Carneiro; Castropil, Wagner; Garofo, Antônio Guilherme Padovani; Cantuária, Anita Lopes; Orselli, Maria Isabel Veras; Luques, Isabela Ugo; Duarte, Marcos

    2015-01-01

    Objective: The objective of this study was to describe the methodology of knee rotation analysis using biomechanics laboratory instruments and to present the preliminary results from a comparative study on patients who underwent anterior cruciate ligament (ACL) reconstruction using the double-bundle technique. Methods: The protocol currently used in our laboratory was described. Three-dimensional kinematic analysis was performed and knee rotation amplitude was measured on eight normal patients (control group) and 12 patients who were operated using the double-bundle technique, by means of three tasks in the biomechanics laboratory. Results: No significant differences between operated and non-operated sides were shown in relation to the mean amplitudes of gait, gait with change in direction or gait with change in direction when going down stairs (p > 0.13). Conclusion: The preliminary results did not show any difference in the double-bundle ACL reconstruction technique in relation to the contralateral side and the control group. PMID:27027003

  3. Meta-analysis of In vitro and Intra-operative Laxities after Single Bundle and Double Bundle Anterior Cruciate Ligament Reconstructions

    PubMed Central

    Gadikota, Hemanth R; Seon, Jong Keun; Chen, Chih-Hui; Wu, Jia-Lin; Gill, Thomas J; Li, Guoan

    2010-01-01

    Purpose The purpose of this study was to objectively evaluate if the double bundle ACL reconstruction can better restore the normal translational and rotational laxities than the conventional single bundle ACL reconstruction among the reported biomechanical studies. Methods A systematic literature search was conducted to identify in vitro and in vivo (intra-operative) biomechanical studies that compared the laxities (anterior or anteroposterior or rotational) between single and double bundle ACL reconstructions. Due to a large variability among the loading conditions and testing methods used to determine the rotational laxities between the studies, a meta-analysis of rotational laxities was not feasible. Results Seven in vitro and three in vivo studies were included in this analysis based on the predefined inclusion criteria. The overall mean difference calculated by the random effects model in the anteroposterior laxity between the single bundle and double bundle ACL reconstruction techniques at 0°, 30°, 60° and 90° of flexion were 0.99 mm, 0.38 mm, 0.34 mm, and 0.07 mm respectively. No statistical significant difference was noted between the two treatments at all flexion angles. Among the nine studies that compared the rotational laxity of single bundle and double bundle ACL reconstructions, four studies reported that double bundle reconstruction can provide a better rotational control compared to the single bundle reconstruction. The other five studies could not identify any significant difference between the two reconstructions in terms of the rotational laxity. Conclusions Both single and double bundle treatment options for anterior cruciate ligament injury result in similar anteroposterior knee joint laxity at time-zero. No 1 conclusive evidence on the superiority of one reconstruction technique over the other in terms of rotation laxity can be obtained due to several variations in the experimental protocol and the parameters used to measure the

  4. Arthroscopic anatomical double bundle anterior cruciate ligament reconstruction: A prospective longitudinal study

    PubMed Central

    Devgan, Ashish; Singh, Amanpreet; Gogna, Paritosh; Singla, Rohit; Magu, Narender Kumar; Mukhopadhyay, Reetadyuti

    2015-01-01

    Background: Single bundle anterior cruciate ligament (ACL) reconstruction has been the current standard of treatment for ACL deficiency. However, a significant subset of patients continue to report residual symptoms of instability with a poor pivot control. Cadaveric biomechanical studies have shown double bundle (DB) ACL reconstructions to restore the knee kinematics better. This study evaluates the outcome of DB ACL reconstruction. Materials and Methods: 30 consecutive patients who underwent anatomic DB ACL reconstruction were included in this prospective longitudinal study. There were all males with a mean age of 25 ± 7.45 years. All patients were prospectively evaluated using GeNouRoB (GNRB) arthrometer, functional knee scores (International Knee Documentation Committee [IKDC] and Lysholm) and postoperative magnetic resonance imaging (MRI) for comparing the graft orientation and footprint of the reconstructed ACL with that of the normal knee. Results: The average followup was 36.2 months. At the time of final followup the mean Lysholm score was 93.13 ± 3.31. As per the objective IKDC score, 26 patients (86.6%) were in Group A while 4 patients (13.3%) were in Group B. The mean differential anterior tibial translation by GNRB, arthrometer was 1.07 ± 0.8 mm (range 0.1-2.3 mm). All cases had a negative pivot shift test. MRI scans of operated and the contralateral normal knee showed the mean sagittal ACL tibial angle coronal ACL tibial angle and tibial ACL footprint to be in accordance with the values of the contralateral, normal knee. Conclusion: The study demonstrates that DB ACL reconstruction restores the ACL anatomically in terms of size and angle of orientation. However, long term studies are needed to further substantiate its role in decreasing the incidence of early osteoarthritic changes compared to the conventional single bundle reconstructions. PMID:26015600

  5. Twenty-Year Experience of a Double-Bundle Anterior Cruciate Ligament Reconstruction

    PubMed Central

    2015-01-01

    Double-bundle (DB) anterior cruciate ligament (ACL) reconstruction using a four-strand semitendinosus tendon was started in our department in July 1994. The motivation for starting the procedure was that the EndoButton with an inside-out procedure instrument became available in Japan. A review article of our DB ACL reconstruction procedure was summarized for the twentieth anniversary of the surgical procedure. Initial tension setting of the two grafts was changed in the first 8 years to achieve better stability during DB ACL reconstruction. A randomized clinical trial (RCT) was started in July 2002 to clarify superiority of the DB procedure to single-bundle (SB) reconstruction under the concept of anatomic reconstruction. Several anatomic studies were performed to describe normal ACL anatomy, which is essential for realizing anatomic reconstruction. A remnant-preserving technique would be an additional option for our DB procedure to improve reconstruction outcomes. Thus, a new remnant-preserving DB procedure was started in 2012. The reproducibility of the new procedure was investigated using three-dimensional computed tomography images. More complex procedures were performed using a transtibial technique and EndoButtons. Initial tension balancing between the two grafts was important for a better outcome. Superiority of knee stability after the DB compared to that after the SB procedure was clarified by the RCT. However, no patient consensus has been reached on any subjective advantage to the DB procedure. Studies of normal ACL anatomy have left questions unresolved regarding where the two tunnels should be created for direct and indirect insertions based on normal anatomy. A new remnant-preserving DB ACL procedure has been practiced. The procedure was more reproducible with respect to creating the femoral tunnel. DB ACL reconstruction using a semitendinosus tendon is an attractive option when pursuing a better outcome for patients. PMID:26217458

  6. Tension Patterns of the Anteromedial and Posterolateral Grafts in a Double-Bundle Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Wu, Changfu; Noorani, Sabrina; Vercillo, Fabio; Woo, Savio L-Y.

    2009-01-01

    The two functional bundles of the anterior cruciate ligament (ACL), namely, the anteromedial (AM) and posterolateral (PL) bundles, must work in concert to control displacement of the tibia relative to the femur for complex motions. Thus, the replacement graft(s) for a torn ACL should possess similar tension patterns. The objective of the study was to examine whether a double bundle ACL reconstruction with the semitendinosus-gracilis autografts could replicate the tension patterns of those for the intact ACL under controlled in vitro loading conditions. By means of a robotic/universal force moment sensor (UFS) testing system, the in situ force vectors (both magnitude and direction) for the AM and PL bundles of the ACL as well as their respective replacement grafts were determined and compared on nine human cadaveric knees. It was found that double bundle ACL reconstruction could closely replicate the in situ force vectors. Under a 134-N anterior tibial load, the resultant force vectors for the intact ACL and the reconstructed ACL had a difference of 5 to 11 N (p>0.05) in magnitude and 1 to 13° (p>0.05) in direction. Whereas, under combined rotatory loads of 10-N-m valgus and 5-N-m internal tibial torques, the corresponding differences were 10 to 16 N and 4 to 11°, respectively. Again, there were no statistically significant differences except at 30° of flexion where the force vector for the AM graft had a 15° (p<0.05) lower elevation angle than did the AM bundle. PMID:19117065

  7. DOUBLE-BUNDLE ANATOMICAL RECONSTRUCTION OF THE ANTERIOR CRUCIATE LIGAMENT: A PROSPECTIVE STUDY WITH TWO-YEAR FOLLOW-UP

    PubMed Central

    Gali, Julio Cesar; Mod, Maurício Sante Bettio; Mimura, Hélio Massahiro; Kushiyama, Walberto

    2015-01-01

    Objective: To prospectively evaluate the results from double-bundle reconstruction of the anterior cruciate ligament, among patients at our clinic, by means of the 2000 protocol of the International Knee Documentation Committee (IKDC). Study Design: Case series; level of evidence IV. Methods: Fifty-eight patients who underwent anatomical reconstruction of the anterior cruciate ligament using an autologous flexor tendon graft by means of the double-bundle technique were evaluated in accordance with the IKDC 2000 protocol. The patients' ages ranged from 17 to 58 years, with a mean of 35.2 years. The follow-up ranged from 24 to 37 months (mean of 28.9 months). Results: Postoperatively, 89.65% of the pivot-shift test findings were negative. In the final evaluation, 44 (75.86%) of the patients' knees were graded as normal, 13 (22.41%) as nearly normal and one (1.72 %) as abnormal. Conclusion: The technique used was effective in promoting restoration of joint stability, without compromising mobility. PMID:27026982

  8. [Implant-free anterior cruciate ligament reconstruction with the patella ligament and press-fit double bundle technique].

    PubMed

    Hertel, P; Behrend, H

    2010-07-01

    Anterior cruciate ligament (ACL) reconstruction using autologous tendons (BTB patellar tendon, hamstrings, quadriceps tendon) in an implant-free fixation technique is becoming more and more popular due to biological and economical reasons. In 1987 an implant-free press-fit fixation technique of a BTB graft from the medial side of the patellar tendon (via mini-arthrotomy) was introduced and first published during the 4th ESKA Conference 1990 in Stockholm. Special emphasis is given to the anatomical orientation of the BTB graft. During the inside-out femoral press-fit fixation the bone-ligament margin of the graft is placed directly into the femoral insertion line of the natural ACL adapting its double-bundle structure. The graft is fixed by press-fit within the tibial metaphysis and its ligamentous part is secured in the metaphysis by harvested cancellous bone blocks driven into the joint line from the outside. The postoperative regime includes weight-bearing as tolerated and free motion. Out of 159 patients 95 could be seen for follow-up after an average of 10.7 years. The final IKDC knee score revealed 22.1% in group A (very good) and 62.1% in group B (good). The Tegner activity level was 6.8 preinjury and 6.0 postoperatively. The average KT 1,000 side-to-side difference was 1.8 mm. Subjectively no patient complained of instability and 99% of the patients could kneel on hard ground with minimal or no complaints. ACL revision surgery due to graft failure was not necessary in any of the patients. Advantages of the described procedure are a narrow anatomical orientation including the double bundle structure of the ACL, rapid graft incorporation by bone-to-bone healing, lack of bone resorption at the graft-host interface, decreased donor site morbidity, cost-effectiveness and ease of possible revision surgery. PMID:20607510

  9. Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction Using an Outside-in Technique: Two- to Six-Year Clinical and Radiological Follow-up

    PubMed Central

    Sim, Jae Ang; Lee, Yong Seuk; Kim, Kyung Ok; Kim, Jong Keun

    2015-01-01

    Purpose We evaluated the clinical and radiological outcomes of double-bundle anterior cruciate ligament (ACL) reconstruction using an outside-in technique with a follow-up of two- to six-years, especially in terms of the sports activity level and radiological degeneration. Materials and Methods Sixty-seven patients who were available for a minimum two-year follow-up after double-bundle ACL reconstruction using an outside-in technique were retrospectively evaluated. The mean follow-up period was 43.7 months. The knee function and stability were evaluated before the operation, one year after the operation (short-term follow-up), and more than two years after the operation (last follow-up). Results Regarding the knee function, the Lysholm score, International Knee Documentation Committee (IKDC) evaluation, and hop test showed significant improvement. Regarding the stability, the Lachman test, pivot shift test, KT-2000 arthrometer data, and anterior drawer radiographs using Telos showed significant improvement. Regarding the sports activity level, the patients who returned to pre-injury level activity was 68.7% according to the Tegner activity score and 76.1% according to the Cincinnati sports activity scale score. The incidence of aggravated degeneration or development of greater than IKDC grade A degeneration after surgery was 10.4%. Conclusions Double-bundle ACL reconstruction using an outside-in technique showed favorable clinical and radiological outcomes with respect to the knee function and stability, joint degeneraion, and, especially, return to pre-injury sports activity. PMID:25750892

  10. Evaluating the distance between the femoral tunnel centers in anatomic double-bundle anterior cruciate ligament reconstruction using a computer simulation

    PubMed Central

    Tashiro, Yasutaka; Okazaki, Ken; Iwamoto, Yukihide

    2015-01-01

    Purpose We aimed to clarify the distance between the anteromedial (AM) bundle and posterolateral (PL) bundle tunnel-aperture centers by simulating the anatomical femoral tunnel placement during double-bundle anterior cruciate ligament reconstruction using 3-D computer-aided design models of the knee, in order to discuss the risk of tunnel overlap. Relationships between the AM to PL center distance, body height, and sex difference were also analyzed. Patients and methods The positions of the AM and PL tunnel centers were defined based on previous studies using the quadrant method, and were superimposed anatomically onto the 3-D computer-aided design knee models from 68 intact femurs. The distance between the tunnel centers was measured using the 3-D DICOM software package. The correlation between the AM–PL distance and the subject’s body height was assessed, and a cutoff height value for a higher risk of overlap of the AM and PL tunnel apertures was identified. Results The distance between the AM and PL centers was 10.2±0.6 mm in males and 9.4±0.5 mm in females (P<0.01). The AM–PL center distance demonstrated good correlation with body height in both males (r=0.66, P<0.01) and females (r=0.63, P<0.01). When 9 mm was defined as the critical distance between the tunnel centers to preserve a 2 mm bony bridge between the two tunnels, the cutoff value was calculated to be a height of 160 cm in males and 155 cm in females. Conclusion When AM and PL tunnels were placed anatomically in simulated double-bundle anterior cruciate ligament reconstruction, the distance between the two tunnel centers showed a strong positive correlation with body height. In cases with relatively short stature, the AM and PL tunnel apertures are considered to be at a higher risk of overlap when surgeons choose the double-bundle technique. PMID:26170727

  11. Anatomic Double-Bundle Posterior Cruciate Ligament Reconstruction.

    PubMed

    Chahla, Jorge; Nitri, Marco; Civitarese, David; Dean, Chase S; Moulton, Samuel G; LaPrade, Robert F

    2016-02-01

    The posterior cruciate ligament (PCL) is known to be the main posterior stabilizer of the knee. Anatomic single-bundle PCL reconstruction, focusing on reconstruction of the larger anterolateral bundle, is the most commonly performed procedure. Because of the residual posterior and rotational tibial instability after the single-bundle procedure and the inability to restore the normal knee kinematics, an anatomic double-bundle PCL reconstruction has been proposed in an effort to re-create the native PCL footprint more closely and to restore normal knee kinematics. We detail our technique for an anatomic double-bundle PCL reconstruction using Achilles and anterior tibialis tendon allografts. PMID:27284530

  12. Bone Tunnel Diameter Measured with CT after Anterior Cruciate Ligament Reconstruction Using Double-Bundle Auto-Hamstring Tendons: Clinical Implications

    PubMed Central

    Yoon, Soo Jeong; Bae, So Young; Wang, Joon Ho

    2015-01-01

    Objective To evaluate the correlation between bone tunnel diameter after anterior cruciate ligament (ACL) reconstruction measured by computed tomography (CT) using multiplanar reconstruction (MPR) and stability or clinical scores. Materials and Methods Forty-seven patients (41 men and 6 women, mean age: 34 years) who had undergone ACL reconstruction with the double bundle technique using auto-hamstring graft and had subsequently received CT scans immediately after the surgery (T1: range, 1-4 days, mean, 2.5 days) and at a later time (T2: range, 297-644 days, mean, 410.4 days) were enrolled in this study. The diameter of each tunnel (two femoral and two tibial) at both T1 and T2 were independently measured using MPR technique by two radiologists. Stability and clinical scores were evaluated with a KT-2000 arthrometer, International Knee Documentation Committee objective scores, and the Lysholm score. Statistical analysis of the correlation between the diameter at T2 or the interval diameter change ratio ([T2 - T1] / T1) and clinical scores or stability was investigated. Results The tibial bone tunnels for the anteromedial bundles were significantly widened at T2 compared with T1 (observer 1, 0.578 mm to 0.698 mm, p value of < 0.001; observer 2, 0.581 mm to 0.707 mm, p value of < 0.001). There was no significant correlation between the diameter at T2 and stability or clinical scores and between the interval change ratio ([T2 - T1] / T1) and stability or clinical scores (corrected p values for all were 1.0). Intraobserver agreement for measurements was excellent (> 0.8) for both observers. Interobserver agreement for measurement was excellent (> 0.8) except for the most distal portion of the femoral bone tunnel for anterior medial bundle in immediate postoperative CT, which showed moderate agreement (concordance correlation coefficient = 0.6311). Conclusion Neither the diameter nor its change ratio during interval follow-up is correlated with stability or clinical

  13. Comparison of single-bundle versus double-bundle anterior cruciate ligament reconstruction after a minimum of 3-year follow-up: a meta-analysis of randomized controlled trials

    PubMed Central

    Chen, Gang; Wang, Shouguo

    2015-01-01

    Both single-bundle (SB) and double-bundle (DB) procedures have been widely used in the treatment of anterior cruciate ligament (ACL) rupture; however, the optimal repair strategy remains considerably controversial. In this meta-analysis of published studies, we compared the results of these two techniques. After systematic review of electronic databases and websites, a total of 8 RCTs reporting data on 941 subjects were included. The objective and subjective functional recovery outcomes were meta-analyzed. The methodological quality was evaluated using the CBRG scale. The overall pooled data showed superiority in rotational stability, the degree of osteoarthritis (OA) changes, and subjective function score postoperatively in patients managed with DB compared with the SB procedure (pivot shift test, P = 0.02; degree of OA, P = 0.02; Lysholm score, P = 0.04; and Tegner scale, P = 0.002, respectively). However, subgroup analysis suggested no difference between the treatment procedures at long-term follow-up. This meta-analysis demonstrated that the DB technique could result in better rotational stability and higher subjective function score and was effective in preventing OA compared to SB in the mid-term treatment of the injured ACL. Further studies with better design involving larger sample sizes and longer-term follow-up are required. PMID:26628943

  14. A Comparison of Anatomic Double- And Single-bundle Techniques for Anterior Cruciate Ligament Reconstruction, A Prospective Randomized Study with A 5-year Follow-up

    PubMed Central

    Karikis, Ioannis; Desai, Neel; Sernert, Ninni; Rostgard-Christensen, Lars; Kartus, Juri T.

    2016-01-01

    Objectives: The purpose of this study was to compare the mid-term outcome after arthroscopic anterior cruciate ligament (ACL) reconstruction with either the anatomic double-bundle (DB) or anatomic single-bundle (SB) technique using hamstring tendon autografts in an unselected group of patients. Methods: 103 patients (33 women, 70 men; median age, 27 years; range, 18-52 years) were randomized and underwent ACL reconstruction (DB group; n=53 and SB group; n=50). All reconstructions were performed anatomically, identifying the ACL footprints, using the anteromedial portal for the femoral tunnel drilling and utilizing interference screw for tibial and femoral fixation. One blinded observer examined the patients both preoperatively and at follow-up (median, 64 months; range, 55-75 months). Radiographic evaluation of OA was performed using the Ahlbäck, Kellgren-Lawrence and Fairbanks grading systems in the early postoperative period and at follow up. Results: Preoperatively, no differences were found between the study groups apart from the pre-injury Tegner activity level, which was lower in the DB group (p=0.02). Eighty-seven patients (83%) were available for examination at 5-year follow-up. There were no significant differences between the groups in terms of the pivot-shift test, KT-1000 arthrometer laxity measurements, manual Lachman test, One-leg-hop test, Square-hop test, range of motion, Lysholm knee scoring scale, Tegner activity scale and Knee Injury and Osteoarthritis Outcome Score (KOOS). Correspondingly, no differences were found between the groups regarding the presence of OA at follow-up. Both DB and SB groups improved significantly at follow-up compared with the preoperative assessment. Conclusion: At mid-term follow-up of an unselected group of patients, anatomic DB reconstruction was not superior to anatomic SB reconstruction in terms of the pivot-shift test or subjective and objective outcome variables, as seen in this prospective randomized study

  15. Double bundle or single bundle plus extraarticular tenodesis in ACL reconstruction? A CAOS study.

    PubMed

    Monaco, E; Labianca, L; Conteduca, F; De Carli, A; Ferretti, A

    2007-10-01

    Anatomic reconstructions of anterior cruciate ligament (ACL) with double bundle gracilis and semitendonosus tendons graft, reproducing AM and PL bundles, have been introduced to offer a better biomechanical outcome, especially during rotatory loads. On the other hand, many methods of tenodesing the lateral aspect of the tibia to the femur to reduce internal rotation (IR) of the tibia and minimize anterior translation of the tibia relative to the femur as a backup for intra-articular reconstruction, have been also suggested. The goal of this study is to evaluate the effect, on the IR of the tibia, of a lateral reconstruction in addition to a standard single bundle ACL reconstruction as compared with an anatomic double bundle ACL reconstruction. Computer assisted ACL reconstruction has been used because it could be very effective in evaluating the global kinematic performance of the reconstructed knee. We selected 20 consecutive ACL reconstruction procedures to be performed in males in our hospital. Patients were alternately assigned to one of the two groups--group A: standard single bundle ACL reconstruction with doubled gracilis and semitendinosus tendons graft with an arthroscopically assisted two incisions technique and a lateral extraarticular reconstruction; group B: double bundle ACL reconstruction with doubled gracilis and semitendinosus tendons graft with an arthroscopically assisted two incisions technique. In all ACL reconstruction procedures navigation process was performed. Both surgical techniques reduced significantly AP displacement, IR and external rotation (ER) of the tibia respect to pre-operative ACL deficient condition (p<0.05). Comparing the group A after the single bundle reconstruction and the group B after the AM bundle fixation, non differences were found in AP displacement, IR and ER of the tibia (p=0.75, p=0.07 and p=0.07 respectively; power: 0.94). Comparing the group A after the addition of the lateral tenodesis and group B after the PL

  16. Lateral Knee Pain after Outside-in Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction Using the TightRope RT

    PubMed Central

    Kuribayashi, So; Nakayama, Shuichi; Nakazato, Keisuke; Fukubayashi, Toru; Okinaga, Shuji

    2016-01-01

    The anterior cruciate ligament (ACL) TightRope RT (TR) was recently introduced as a novel cortical suspension device for ACL reconstruction. It has an adjustable graft loop that gives the surgeon some advantages during ACL reconstruction. We report three patients who required removal of the TR after an outside-in anatomical ACL reconstruction because of lateral knee pain. We assumed that the knee pain was associated with friction between the TR button of the posterolateral bundle and iliotibial band (ITB). Placing the TR button close to the lateral epicondyle and tissue interposition between the TR button and lateral femoral cortex may be potential risk factors for ITB irritation. Therefore, we recommend not placing the TR button close to the top of the lateral epicondyle and reducing the tissue interposition between the TR button and lateral femoral cortex as much as possible. PMID:26955618

  17. Radiological evidence for the triple bundle anterior cruciate ligament.

    PubMed

    MacKay, James W; Whitehead, Harry; Toms, Andoni P

    2014-10-01

    The anterior cruciate ligament (ACL) has traditionally been described as having two bundles--one anteromedial and one posterolateral. This has been challenged by studies proposing the existence of a third, intermediate, bundle with distinct functional significance, an arrangement that has been described in a number of domesticated animal species. No radiological evidence for the triple bundle ACL has previously been described. A prevalence study was carried out on 73 consecutive human knee magnetic resonance (MR) studies to determine the number of visible bundles, excluding individuals with a history of ACL injury or mucoid degeneration. A triple bundle ACL was demonstrated in 15 out of 73 human knees (20.5%, 95% confidence interval 12.9-31.2%). This is the first radiological description of the human triple bundle ACL. There was MR imaging evidence of a triple bundle ACL in approximately one fifth of human knees in this study. PMID:24890455

  18. Balance Ability and Proprioception after Single-Bundle, Single-Bundle Augmentation, and Double-Bundle ACL Reconstruction

    PubMed Central

    Ma, Yubao; Iwaki, Daisuke; Asaeda, Makoto; Adachi, Nobuo; Ochi, Mitsuo

    2014-01-01

    Purpose. The present study sought to determine the influences of single-bundle (SB), single-bundle augmentation (SBA), and double-bundle (DB) reconstructions on balance ability and proprioceptive function. Methods. 67 patients who underwent a single- or double-bundle ACL reconstruction or a SBA using multistranded autologous hamstring tendons were included in this study with a 1-year follow-up. Body sway and knee kinesthesia (using the threshold to detect passive motion test (TTDPM)) were measured to indicate balance ability and proprioceptive function, respectively. Additionally, within-subject differences in anterior-posterior stability of the tibia and lower extremity muscle strength were evaluated before and after surgery. Results. At 6 and 12 months after surgery, DB reconstruction resulted in better balance and proprioceptive function than SB reconstruction (P < 0.05). Although no significant difference was observed in balance ability or proprioceptive function between the SBA and DB reconstructions, knee stability was significantly better with SBA and DB reconstructions than SB reconstruction (P < 0.05). No significant differences were found in quadriceps and hamstrings strength among the three reconstruction techniques. Conclusions. Our findings consider that joint stability, proprioceptive function, and balance ability were superior with SBA and DB reconstructions compared to SB reconstruction at 6 and 12 months after surgery. PMID:25614884

  19. Partial tears of anterior cruciate ligament: Results of single bundle augmentation

    PubMed Central

    Sabat, Dhananjaya; Kumar, Vinod

    2015-01-01

    Background: Partial tears of the anterior cruciate ligament (ACL) are common and usually present with symptomatic instability. The remnant fibers are usually removed and a traditional ACL reconstruction is done. But with increased understanding of ACL double bundle anatomy, the remnant tissue preservation along with a single bundle augmentation of the torn bundle is also suggested. The purpose of this study was to evaluate the results of selective anatomic augmentation of symptomatic partial ACL tears. Our hypothesis is that this selective augmentation of partial ACL tears could restore knee stability and function. Materials and Methods: Consecutive cases of 314 ACL reconstructions, 40 patients had intact ACL fibers in the location corresponding to the anteromedial (AM) or posterolateral (PL) bundle and were diagnosed as partial ACL tears perioperatively. All patients underwent selective augmentation of the torn bundle, while keeping the remaining fibers intact using autogenous hamstring graft. A total of 38 patients (28 males, 10 females) were available with a minimum of 3 years followup. 26 cases had AM bundle tears and 12 cases had PL bundle tears respectively. Patients were assessed with International Knee Documentation Committee (IKDC) 2000 Knee Evaluation Form, Lysholm score; instrumented knee testing was performed with the arthrometer (KT 2000). Statistical analysis was performed to compare the preoperative and postoperative objective evaluation. Results: At 3 years followup, 31.6% patients were graded A, 65.8% were graded B and 2.6% was graded C at IKDC objective evaluation. Manual laxity tests, Lysholm's score, mean side to side instrumental laxity and Tegner activity score improved significantly. 76% patients returned to preinjury level of sports activity after augmentation. Conclusion: The results of anatomic single bundle augmentation in partial ACL tears are encouraging with excellent improvement in functional scores, side to side laxity and return to

  20. Single-Bundle Versus Double-Bundle Acl Reconstructions in Isolation and in Conjunction with Extra-Articular Iliotibial Band Tenodesis

    PubMed Central

    Butler, Paul D.; Mellecker, Chloe J.; Rudert, M. James; Albright, John P.

    2013-01-01

    Background Intra-articular anterior cruciate ligament (ACL) reconstruction has been the primary treatment option for isolated ACL injuries for many years. An anatomic double-bundle reconstruction has been devised in an effort to improve rotational control. The role of the extra-articular iliotibial band tenodesis in ACL injuries has evolved from primary treatment, to an adjuvant secondary procedure, to being used more selectively in revision ACL reconstructions. Hypotheses: 1) Single-bundle and doublebundle intra-articular ACL reconstructions will both restore pre-injury laxity measurements in an isolated ACL injury cadaver model. 2) The deep iliotibial band structures contribute to rotational control and in a dual ACL + ITB injury cadaver model, ACL reconstruction alone cannot restore rotational control. Study Design Controlled Laboratory Design Methods 17 fresh frozen cadavers received intra-articular reconstructions, seven single-bundle and ten double-bundle; laxity was measured with the ACL intact/ITB intact, ACL reconstructed/ITB intact, after cutting the ITB, and after an ITB tenodesis procedure; laxity measurements of anterior tibial translation(ATT) and internal rotation(IR) were measured following applications of an anterior shear force, an internal torque and a coupled anterior shear force-internal torque at 30 and 90 degrees of flexion. Results Single-bundle and double-bundle ACL reconstructions both restored IR to a native knee state under isolated internal torques and under coupled forces. Both reconstruction techniques also re-established anterior tibial translation to at least the pre-ACL injury level, with over-constraint in the double-bundle subgroup [5.00 (+2.11) to 3.50(+1.18), p-value 0.026] under coupled loads at 30 degrees of flexion. With the individual ACL reconstructions held constant, under coupled forces mean IR increased in the single-bundle subgroup [13.7(+1.1) to 17.6(+1.2), p-value 0.004] and the double-bundle subgroup [9.5(+1.0) to

  1. The contribution of each anterior cruciate ligament bundle to the Lachman test: a cadaver investigation.

    PubMed

    Christel, P S; Akgun, U; Yasar, T; Karahan, M; Demirel, B

    2012-01-01

    The clinical diagnosis of a partial tear of the anterior cruciate ligament (ACL) is still subject to debate. Little is known about the contribution of each ACL bundle during the Lachman test. We investigated this using six fresh-frozen cadaveric lower limbs. Screws were placed in the femora and tibiae as fixed landmarks for digitisation of the bone positions. The femur was secured horizontally in a clamp. A metal hook was screwed to the tibial tubercle and used to apply a load of 150 N directed anteroposteriorly to the tibia to simulate the Lachman test. The knees then received constant axial compression and 3D knee kinematic data were collected by digitising the screw head positions in 30° flexion under each test condition. Measurements of tibial translation and rotation were made, first with the ACL intact, then after sequential cutting of the ACL bundles, and finally after complete division of the ACL. Two-way analysis of variance analysis was performed. During the Lachman test, in all knees and in all test conditions, lateral tibial translation exceeded that on the medial side. With an intact ACL, both anterior and lateral tibial landmarks translated significantly more than those on the medial side (p < 0.001). With sequential division of the ACL bundles, selective cutting of the posterolateral bundle (PLB) did not increase translation of any landmark compared with when the ACL remained intact. Cutting the anteromedial bundle (AMB) resulted in an increased anterior translation of all landmarks. Compared to the intact ACL, when the ACL was fully transected a significant increase in anterior translation of all landmarks occurred (p < 0.001). However, anterior tibial translation was almost identical after AMB or complete ACL division. We found that the AMB confers its most significant contribution to tibial translation during the Lachman test, whereas the PLB has a negligible effect on anterior translation. Section of the PLB had a greater effect on increasing

  2. Two Helpful MRI Signs for Evaluation of Posterolateral Bundle Tears of the Anterior Cruciate Ligament

    PubMed Central

    Volokhina, Yulia V.; Syed, Hasan M.; Pham, Peter H.; Blackburn, Allie K.

    2015-01-01

    Background: Diagnosis of partial anterior cruciate ligament (ACL) tears is difficult on magnetic resonance imaging (MRI), particularly the isolated tears of the posterolateral bundle. Purpose: To describe 2 MRI signs of partial ACL tear involving the posterolateral bundle on conventional knee MRI sequences, specifically, the “gap” and “footprint” signs. Study Design: Case-control study. Methods: We retrospectively reviewed the MRI appearance of the ACL in 11 patients with arthroscopically proven partial ACL tears isolated to the posterolateral bundle, as well as in 10 patients with arthroscopically proven intact ACLs, and evaluated for the presence of gap and/or footprint signs. Results: There was high degree of sensitivity and specificity associated with the MRI findings of “gap” and “footprint” signs with arthroscopically proven isolated posterolateral bundle tears. Conclusion: Gap and footprint signs are suggestive of posterolateral bundle tear of the ACL, and the presence of 1 or both of these imaging findings should alert the radiologist to the possibility of a posterolateral bundle tear. PMID:26535387

  3. Anatomic Double Bundle single tunnel Foreign Material Free ACL-Reconstruction – a technical note

    PubMed Central

    Felmet, Gernot

    2011-01-01

    Summary The anterior cruciate ligament (ACL) consists of two bundles, the anteromedial (AM) and posterolateral bundle (PM). Double bundle reconstructions appear to give better rotational stability. The usual technique is to make two tunnels in the femur and two in the tibia. This is difficult and in small knees may not even be possible. We have developed a foreign material free press fit fixation for double bundle ACL reconstruction using a single femoral tunnel (R). This is based on the ALL PRESS FIT ACL reconstruction. It is suitable for the most common medium and, otherwise difficult, small sizes of knees. Method: Using diamond edged wet grinding hollow reamers, bone cylinders in different diameters are harvested from the implantation tunnels of the tibia and femur and used for the press fit fixation. Using the press fit technique the graft is first fixed in tibia. It is then similarly fixed under tension in the femoral side with the knee in 120 degree flexion. This is called Bottom To Top Fixation (BTT). On extending the knee the graft tension is self adapting. Depending on the size of the individual knee, the diameter of the femoral bone plug is varied from 8 to 13 mm to achieve an anatomic spread with a double bundle-like insertion. The tibia tunnel can be applied with two 7 or 8 mm diameter tunnels overlapping to a semi oval tunnel between 10 to 13 mm. Results: Since May 2003 we have carried out ACL-reconstructions with Hamstring grafts without foreign material using the ALL PRESS FIT technique. Initially, an 8 mm press fit fixation was used proximally with good results. Since April 2008, the range of diameters was increased up to 13 mm. The results of the Lachman tests have been good to excellent. Results of the Pivot shift test suggested more stability with femoral broader diameters of 9,5 to 13 mm. Conclusions: The foreign material free fixation of ham-string in the ALL PRESS FIT Bottom To Top Fixation is a successful method for ACL Reconstruction. The

  4. Anatomical versus Non-Anatomical Single Bundle Anterior Cruciate Ligament Reconstruction: A Cadaveric Study of Comparison of Knee Stability

    PubMed Central

    Lim, Hong-Chul; Yoon, Yong-Cheol; Wang, Joon-Ho

    2012-01-01

    Background The purpose of this study was to compare the initial stability of anatomical and non-anatomical single bundle anterior cruciate ligament (ACL) reconstruction and to determine which would better restore intact knee kinematics. Our hypothesis was that the initial stability of anatomical single bundle ACL reconstruction would be superior to that of non-anatomical single bundle ACL reconstruction. Methods Anterior tibial translation (ATT) and internal rotation of the tibia were measured with a computer navigation system in seven pairs of fresh-frozen cadaveric knees under two testing conditions (manual maximum anterior force, and a manual maximum anterior force combined with an internal rotational force). Tests were performed at 0, 30, 60, and 90 degrees of flexion with the ACL intact, the ACL transected, and after reconstruction of one side of a pair with either anatomical or non-anatomical single bundle ACL reconstruction. Results Under manual maximal anterior force, both reconstruction techniques showed no significant difference of ATT when compared to ACL intact knee state at 30° of knee flexion (p > 0.05). Under the combined anterior and internal rotatory force, non-anatomical single-bundle ACL reconstruction showed significant difference of ATT compared to those in ACL intact group (p < 0.05). In contrast, central anatomical single bundle ACL reconstruction showed no significant difference of ATT compared to those in ACL intact group (p > 0.05). Internal rotation of the tibia showed no significant difference in the ACL intact, the ACL transected, non-anatomical reconstructed and anatomical reconstructed knees. Conclusions Anatomical single bundle ACL reconstruction restored the initial stability closer to the native ACL under combined anterior and internal rotational forces when compared to non-anatomical ACL single bundle reconstruction. PMID:23205233

  5. Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction With Remnant Preservation Using Outside-In Technique

    PubMed Central

    Lee, Byung-Ill; Kwon, Sai-Won; Choi, Hyung-Suk; Chun, Dong-Il; Kim, Yong-Beom; Kim, Byoung-Min

    2015-01-01

    This report describes a modified anatomic single-bundle anterior cruciate ligament (ACL) reconstruction technique using the FlipCutter guide pin (Arthrex, Naples, FL) as a retrograde drill and a cortical suspensory fixation device (TightRope; Arthrex) with an adjustable graft loop length. Preservation of the ACL remnant as a biological sleeve for the graft is an important issue from the viewpoints of acceleration of revascularization and ligamentization, preservation of the proprioceptive nerve fibers, enhancement of the biological environment for healing, and maintenance of the anchor point at the native tibial attachment, in addition to yielding a lower incidence of tibial bone tunnel enlargement. The goal of our technique is to obtain some advantages of the remnant-preserving technique through an anatomic single-bundle ACL reconstruction, which is performed to minimize damage to the ACL tibial remnant. PMID:26759771

  6. Anatomical Single-bundle Anterior Cruciate Ligament Reconstruction Using a Freehand Transtibial Technique

    PubMed Central

    Nha, Kyung-Wook; Han, Jae-Hwi; Kwon, Jae-Ho; Kang, Kyung-Woon; Park, Hyung-Joon

    2015-01-01

    Purpose In anatomical single-bundle (SB) anterior cruciate ligament (ACL) reconstruction, the traditional transtibial approach can limit anatomical placement of the femoral tunnel. Surgical Technique We present a novel three-point freehand technique that allows for anatomic SB ACL reconstruction with the transtibial technique. Materials and Methods Between January 2012 and December 2012, 55 ACL reconstructions were performed using the three-point freehand technique. All the patients were followed for a minimum of 12 months post-operatively. Clinical evaluation was done using the Lysholm score and International Knee Documentation Committee (IKDC) grade. All patients were analyzed by 3-dimensional computed tomography (3D CT) at 1 week after surgery. Results The mean Lysholm score improved from 68.2±12.7 points preoperatively to 89.2±8.2 points at final follow-up. At final follow-up, the IKDC grade was normal in 42 patients and nearly normal in 13 patients. None of the patients had a positive pivot shift test, anterior drawer test and Lachman test at final follow-up. The anatomical position of the femoral tunnel was confirmed on 3D CT scans. Conclusions The three-point freehand technique for SB transtibial ACL reconstruction is a simple, anatomic technique showing good clinical results. PMID:26060611

  7. Structures and characterizations of bundles of collapsed double-walled carbon nanotubes.

    PubMed

    Zhong, X H; Wang, R; Liu, L B; Kang, M; Wen, Y Y; Hou, F; Feng, J M; Li, Y L

    2012-12-21

    The performance of carbon nanotube fibers (CNTFs) significantly depends on the packing styles of carbon nanotube (CNT) bundles. Revealing the structures and characterizations of CNT bundles is contributive to understanding the structures, properties and even the formation of CNTFs during chemical vapor deposition (CVD) processing. In this paper, bundles consisting of collapsed double-walled carbon nanotubes (CDWNT) in continuous CNTFs fabricated from CVD processing were characterized and analyzed by transmission electronic microscopy (TEM) and x-ray diffraction (XRD). TEM observations show that the continuous CNTFs are composed of CDWNT-bundle units. CDWNT-bundle units of 10-20 nm in thickness contain near numbers of collapsed tubes. The degree of collapse of the CDWNTs varies with their location in the bundle and their own diameter. CDWNT-bundle units pack side by side or face to face, assembling into super-bundles with diameters of 200-300 nm. XRD patterns show that three novel and strong peaks appear at 10°-15°, 21.3° and 23.7°, respectively, corresponding to CDWNT two side pores (10°-15°) and CDWNT layers (21.3° and 23.7°), which indicates the collapsed tube structures in CNTFs are common characterizations. Finally, a collapse mechanism is discussed from the observation and analysis. PMID:23196759

  8. Anatomic Single Bundle Anterior Cruciate Ligament Reconstruction by Low Accessory Anteromedial Portal Technique: An In Vivo 3D CT Study

    PubMed Central

    Lee, Kwang Won; Chi, Yong Joo; Yang, Dae Suk; Kim, Ha Yong; Choy, Won Sik

    2014-01-01

    Purpose Proper femoral tunnel position is important for anatomical reconstruction of the anterior cruciate ligament (ACL). The purpose of this study was to evaluate the positions of femoral and tibial tunnels created using an accessory anteromedial portal technique in single bundle ACL reconstruction. Materials and Methods The femoral tunnel was targeted at the mid-portion of the ACL bundles. We evaluated postoperative computed tomography scans of 32 patients treated by ACL reconstruction using a free-hand low accessory anteromedial portal technique. On the tibial side, the tunnel position was evaluated using Tsukada's method. On the femoral side, the position was evaluated using 1) the quadrant method, 2) Mochizuki's method, 3) Mochizuki's method, and 4) Takahashi's method. Tunnel obliquity was also evaluated. Results The mean tibial tunnel position was located at 44.6%±2.5% anterior from the anterior margin and 48.0%±3.0% in medial from the medial margin. The mean femoral tunnel position was located at the center between the anteromedial and posterolateral bundles: Quadrant method, 26.7%±2.7%/30.0%±2.9%; Watanabe's method, 37.7%±2.5%/26.6%±2.2%; Mochizuki's method, 38.7%±2.7%; Takahashi's method, 21.8%±2.2%. The mean femoral tunnel obliquity was 57.7°±6.2° in the sagittal plane and 49.9°±5.6° in the coronal plane. Conclusions In anatomic single bundle ACL reconstruction, the low anteromedial portal technique can restore accurate position of the native footprint. Accurate femoral tunnel position facilitates recovery of stability and decreases graft failure rate. PMID:24944975

  9. The Correlation of Tunnel Position, Orientation and Tunnel Enlargement in Outside-in Single-Bundle Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Ko, Young Won; Rhee, Seung Jun; Kim, In Woo

    2015-01-01

    Purpose Tunnel widening after anterior cruciate ligament (ACL) reconstruction is a frequently described phenomenon. The possible etiology is multi-factorial with some mechanical and biological factors. Among those, we intended to determine the relation between the location and orientation of the femoral tunnel and the femoral tunnel enlargement after outside-in single-bundle ACL reconstruction. Materials and Methods A retrospective study including 42 patients who received single-bundle ACL reconstruction with the outside-in technique was conducted. Femoral and tibial tunnel locations were evaluated with the quadrant method and bird's-eye view using volume-rendering computed tomography. The angle and diameter of bone tunnel and the degree of tunnel enlargement were evaluated using standard radiographs. Results The degree of femoral tunnel enlargements were 42% and 36% on the anteroposterior (AP) and lateral radiographs, respectively, and the degree of tibial tunnel enlargements were 22% and 23%, respectively. Shallower location of the femoral tunnel was significantly correlated with greater femoral tunnel enlargement on the AP radiograph (r=0.998, p=0.004) and the lateral radiograph (r=0.72, p=0.005) as was the higher location of the femoral tunnel on the AP radiograph (r=-0.47, p=0.01) and the lateral radiograph (r=-0.36, p=0.009) at 12 months after surgery. Conclusions This study revealed that more anterior and higher location and more horizontal orientation of the femoral tunnel in coronal plane could result in widening of the femoral tunnel in outside-in single-bundle ACL reconstruction. PMID:26672479

  10. Change in the Pathologic Supraspinatus: A Three-Dimensional Model of Fiber Bundle Architecture within Anterior and Posterior Regions.

    PubMed

    Kim, Soo Y; Sachdeva, Rohit; Li, Zi; Lee, Dongwoon; Rosser, Benjamin W C

    2015-01-01

    Supraspinatus tendon tears are common and lead to changes in the muscle architecture. To date, these changes have not been investigated for the distinct regions and parts of the pathologic supraspinatus. The purpose of this study was to create a novel three-dimensional (3D) model of the muscle architecture throughout the supraspinatus and to compare the architecture between muscle regions and parts in relation to tear severity. Twelve cadaveric specimens with varying degrees of tendon tears were used. Three-dimensional coordinates of fiber bundles were collected in situ using serial dissection and digitization. Data were reconstructed and modeled in 3D using Maya. Fiber bundle length (FBL) and pennation angle (PA) were computed and analyzed. FBL was significantly shorter in specimens with large retracted tears compared to smaller tears, with the deeper fibers being significantly shorter than other parts in the anterior region. PA was significantly greater in specimens with large retracted tears, with the superficial fibers often demonstrating the largest PA. The posterior region was absent in two specimens with extensive tears. Architectural changes associated with tendon tears affect the regions and varying depths of supraspinatus differently. The results provide important insights on residual function of the pathologic muscle, and the 3D model includes detailed data that can be used in future modeling studies. PMID:26413533

  11. Change in the Pathologic Supraspinatus: A Three-Dimensional Model of Fiber Bundle Architecture within Anterior and Posterior Regions

    PubMed Central

    Kim, Soo Y.; Sachdeva, Rohit; Li, Zi; Lee, Dongwoon; Rosser, Benjamin W. C.

    2015-01-01

    Supraspinatus tendon tears are common and lead to changes in the muscle architecture. To date, these changes have not been investigated for the distinct regions and parts of the pathologic supraspinatus. The purpose of this study was to create a novel three-dimensional (3D) model of the muscle architecture throughout the supraspinatus and to compare the architecture between muscle regions and parts in relation to tear severity. Twelve cadaveric specimens with varying degrees of tendon tears were used. Three-dimensional coordinates of fiber bundles were collected in situ using serial dissection and digitization. Data were reconstructed and modeled in 3D using Maya. Fiber bundle length (FBL) and pennation angle (PA) were computed and analyzed. FBL was significantly shorter in specimens with large retracted tears compared to smaller tears, with the deeper fibers being significantly shorter than other parts in the anterior region. PA was significantly greater in specimens with large retracted tears, with the superficial fibers often demonstrating the largest PA. The posterior region was absent in two specimens with extensive tears. Architectural changes associated with tendon tears affect the regions and varying depths of supraspinatus differently. The results provide important insights on residual function of the pathologic muscle, and the 3D model includes detailed data that can be used in future modeling studies. PMID:26413533

  12. Experimental-computational study of shear interactions within double-walled carbon nanotube bundles.

    PubMed

    Filleter, Tobin; Yockel, Scott; Naraghi, Mohammad; Paci, Jeffrey T; Compton, Owen C; Mayes, Maricris L; Nguyen, Sonbinh T; Schatz, George C; Espinosa, Horacio D

    2012-02-01

    The mechanical behavior of carbon nanotube (CNT)-based fibers and nanocomposites depends intimately on the shear interactions between adjacent tubes. We have applied an experimental-computational approach to investigate the shear interactions between adjacent CNTs within individual double-walled nanotube (DWNT) bundles. The force required to pull out an inner bundle of DWNTs from an outer shell of DWNTs was measured using in situ scanning electron microscopy methods. The normalized force per CNT-CNT interaction (1.7 ± 1.0 nN) was found to be considerably higher than molecular mechanics (MM)-based predictions for bare CNTs (0.3 nN). This MM result is similar to the force that results from exposure of newly formed CNT surfaces, indicating that the observed pullout force arises from factors beyond what arise from potential energy effects associated with bare CNTs. Through further theoretical considerations we show that the experimentally measured pullout force may include small contributions from carbonyl functional groups terminating the free ends of the CNTs, corrugation of the CNT-CNT interactions, and polygonization of the nanotubes due to their mutual interactions. In addition, surface functional groups, such as hydroxyl groups, that may exist between the nanotubes are found to play an unimportant role. All of these potential energy effects account for less than half of the ~1.7 nN force. However, partially pulled-out inner bundles are found not to pull back into the outer shell after the outer shell is broken, suggesting that dissipation is responsible for more than half of the pullout force. The sum of force contributions from potential energy and dissipation effects are found to agree with the experimental pullout force within the experimental error. PMID:22214436

  13. Nonlinear dynamics of bi-layered graphene sheet, double-walled carbon nanotube and nanotube bundle

    NASA Astrophysics Data System (ADS)

    Gajbhiye, Sachin O.; Singh, S. P.

    2016-05-01

    Due to strong van der Waals (vdW) interactions, the graphene sheets and nanotubes stick to each other and form clusters of these corresponding nanostructures, viz. bi-layered graphene sheet (BLGS), double-walled carbon nanotube (DWCNT) and nanotube bundle (NB) or ropes. This research work is concerned with the study of nonlinear dynamics of BLGS, DWCNT and NB due to nonlinear interlayer vdW forces using multiscale atomistic finite element method. The energy between two adjacent carbon atoms is represented by the multibody interatomic Tersoff-Brenner potential, whereas the nonlinear interlayer vdW forces are represented by Lennard-Jones 6-12 potential function. The equivalent nonlinear material model of carbon-carbon bond is used to model it based on its force-deflection relation. Newmark's algorithm is used to solve the nonlinear matrix equation governing the motion of the BLGS, DWCNT and NB. An impulse and harmonic excitations are used to excite these nanostructures under cantilevered, bridged and clamped boundary conditions. The frequency responses of these nanostructures are computed, and the dominant resonant frequencies are identified. Along with the forced vibration of these structures, the eigenvalue extraction problem of armchair and zigzag NB is also considered. The natural frequencies and corresponding mode shapes are extracted for the different length and boundary conditions of the nanotube bundle.

  14. Differences of Intra-Articular Graft Length between Sandwich-Style Reconstruction and Zhao-Style Non-Remnant-Preserving Double-Bundle Reconstruction of Posterior Cruciate Ligament

    PubMed Central

    Xu, Caiqi; Zhao, Song; Dong, Shikui; Zhang, Yang; Zhao, Jinzhong

    2016-01-01

    Appropriate graft length within the joint and inside the osseous tunnel is essential for achieving posterior stability and adequate anchorage strength. Because of the curving path and thickness of the graft in double-bundle posterior cruciate ligament (PCL) reconstruction, especially in double-bundle PCL augmentation (with remnant preservation), the actual intra-articular length of PCL grafts, which remains unknown, may be longer than previously published values. The main purpose of the current study is to measure the actual intra-articular graft length required in sandwich-style PCL reconstruction (remnant-preserving double-bundle PCL augmentation) and Zhao-style non-remnant-preserving double-bundle PCL reconstruction (semi-anatomic double-bundle PCL reconstruction using double-double tunnel with tibial medial and lateral arrangement). Nine matched pairs of intact cadaveric knees were randomized between two groups and respectively received sandwich-style PCL reconstruction (remnant-preserving group) and Zhao-style non-remnant-preserving double-bundle PCL reconstruction (non-remnant-preserving group). The tunnel positions were exactly the same in two groups. The anterolateral (AL) bundle was reconstructed with four-stranded semitendinosus tendon, and the posteromedial (PM) bundle was reconstructed with four-stranded gracilis tendon. For each bundle, the length of the graft portion within the joint was measured. The current study indicated that in remnant-preserving group, the average intra-articular exposed portion was 42.0 mm (SD, 1.3 mm; range, 40.0 mm to 43.4 mm) for the AL bundle and 32.5 mm (SD, 2.9 mm; range, 27.8 mm to 35.8 mm) for the PM bundle. In non-remnant-preserving group, the intra-articular exposed portion was 34.5 mm (SD, 1.0 mm; range, 32.7 mm to 36.0 mm) for the AL bundle and 29.1 mm (SD, 2.1 mm; range, 25.2 mm to 31.9 mm) for the PM bundle. For both the AL and PM bundles, significant differences were found in average intra-articular graft length

  15. Differences of Intra-Articular Graft Length between Sandwich-Style Reconstruction and Zhao-Style Non-Remnant-Preserving Double-Bundle Reconstruction of Posterior Cruciate Ligament.

    PubMed

    Shen, Peng; Li, Xiaoxi; Xu, Caiqi; Zhao, Song; Dong, Shikui; Zhang, Yang; Zhao, Jinzhong

    2016-01-01

    Appropriate graft length within the joint and inside the osseous tunnel is essential for achieving posterior stability and adequate anchorage strength. Because of the curving path and thickness of the graft in double-bundle posterior cruciate ligament (PCL) reconstruction, especially in double-bundle PCL augmentation (with remnant preservation), the actual intra-articular length of PCL grafts, which remains unknown, may be longer than previously published values. The main purpose of the current study is to measure the actual intra-articular graft length required in sandwich-style PCL reconstruction (remnant-preserving double-bundle PCL augmentation) and Zhao-style non-remnant-preserving double-bundle PCL reconstruction (semi-anatomic double-bundle PCL reconstruction using double-double tunnel with tibial medial and lateral arrangement). Nine matched pairs of intact cadaveric knees were randomized between two groups and respectively received sandwich-style PCL reconstruction (remnant-preserving group) and Zhao-style non-remnant-preserving double-bundle PCL reconstruction (non-remnant-preserving group). The tunnel positions were exactly the same in two groups. The anterolateral (AL) bundle was reconstructed with four-stranded semitendinosus tendon, and the posteromedial (PM) bundle was reconstructed with four-stranded gracilis tendon. For each bundle, the length of the graft portion within the joint was measured. The current study indicated that in remnant-preserving group, the average intra-articular exposed portion was 42.0 mm (SD, 1.3 mm; range, 40.0 mm to 43.4 mm) for the AL bundle and 32.5 mm (SD, 2.9 mm; range, 27.8 mm to 35.8 mm) for the PM bundle. In non-remnant-preserving group, the intra-articular exposed portion was 34.5 mm (SD, 1.0 mm; range, 32.7 mm to 36.0 mm) for the AL bundle and 29.1 mm (SD, 2.1 mm; range, 25.2 mm to 31.9 mm) for the PM bundle. For both the AL and PM bundles, significant differences were found in average intra-articular graft length

  16. A Comparison of Arthroscopically Assisted Single and Double Bundle Tibial Inlay Reconstruction for Isolated Posterior Cruciate Ligament Injury

    PubMed Central

    Lee, Dong Chul; Park, Chul Hyun; Kim, Won Ho; Jung, Kwang Am

    2010-01-01

    Background This study evaluated the clinical results of arthroscopically assisted single and double bundle tibial inlay reconstructions of an isolated posterior cruciate ligament (PCL) injury. Methods This study reviewed the data for 14 patients who underwent a single bundle tibial inlay PCL reconstruction (Group A) and 16 patients who underwent a double bundle tibial inlay PCL reconstruction (Group B) between August 1999 and August 2002. The mean follow-up period in groups A and B was 90.5 months and 64 months, respectively. Results The Lysholm knee scores in groups A and B increased from an average of 43.3 ± 7.04 and 44.7 ± 5.02 preoperatively to 88.1 ± 7.32 and 88.7 ± 9.11 points at the final follow-up, respectively. In group A, stress radiography using a Telos device showed that the preoperative mean side-to-side differences (SSDs) of 9.5 ± 1.60 mm at 30° of flexion and 9.8 ± 1.70 mm at 90° of flexion were improved to 2.8 ± 1.19 mm and 3.0 ± 1.1 mm, respectively. In group B, the preoperative SSDs of 10.4 ± 1.50 mm at 30° of flexion and 10.7 ± 1.60 mm at 90° of flexion improved to 2.7 ± 1.15 mm and 2.6 ± 0.49 mm, respectively. There was no significant difference in the clinical scores and radiologic findings between the two groups. Conclusions Single bundle and double bundle PCL reconstructions using the tibial inlay technique give satisfactory clinical results in patients with an isolated PCL injury, and there are no significant differences in the clinical and radiological results between the two techniques. These results suggest that it is unnecessary to perform the more technically challenging double bundle reconstruction using the tibial inlay technique in an isolated PCL injury. PMID:20514264

  17. ANATOMICAL RECONSTRUCTION OF ANTERIOR CRUCIATE LIGAMENT OF THE KNEE: DOUBLE BAND OR SINGLE BAND?

    PubMed Central

    Zanella, Luiz Antonio Zanotelli; Junior, Adair Bervig; Badotti, Augusto Alves; Michelin, Alexandre Froes; Algarve, Rodrigo Ilha; de Quadros Martins, Cesar Antonio

    2015-01-01

    Objective: To evaluate the double-band and single-band techniques for anatomical reconstruction of the anterior cruciate ligament of the knee and demonstrate that the double-band technique not only provides greater anterior stability but also causes less pain and a better subjective patient response. Methods: We selected 42 patients who underwent anterior cruciate ligament reconstruction, by means of either the single-band anatomical reconstruction technique, using flexor tendon grafts with two tunnels, or the double-band anatomical reconstruction technique, using four tunnels and grafts from the semitendinosus and gracilis tendons. All fixations were performed using interference screws. There was no variation in the sample. Before the operation, the objective and subjective IKDC scores, Lysholm score and length of time with the injury were evaluated. All these variables were reassessed six months later, and the KT-1000 correlation with the contralateral knee was also evaluated. Results: There was no significant difference between the two groups in subjective evaluations, but the single-band group showed better results in relation to range of motion and objective evaluations including KT-1000 (with statistical significance). Conclusion: Our study demonstrated that there was no difference between the two groups in subjective evaluations, but better results were found using the single-band anatomical technique, in relation to objective evaluations. PMID:27042621

  18. Formation of a Double Diamond Cubic Phase by Thermotropic Liquid Crystalline Self-Assembly of Bundled Bolaamphiphiles.

    PubMed

    Zeng, Xiangbing; Prehm, Marko; Ungar, Goran; Tschierske, Carsten; Liu, Feng

    2016-07-11

    A quaternary amphiphile with swallow-tail side groups displays a new bicontinuous thermotropic cubic phase with symmetry Pn3‾ m and formed by two interpenetrating networks where cylindrical segments are linked by H bonds at tetrahedral junctions. Each network segment contains two bundles, each containing 12 rod-like mesogens, lying along the segment axis. This assembly leads to the first thermotropic structure of the "double diamond" type. A quantitative geometric model is proposed to explain the occurrence of this rare phase. PMID:27270840

  19. Single bundle anterior cruciate reconstruction does not restore normal knee kinematics at six months: an upright MRI study.

    PubMed

    Nicholson, J A; Sutherland, A G; Smith, F W

    2011-10-01

    Abnormal knee kinematics following reconstruction of the anterior cruciate ligament may exist despite an apparent resolution of tibial laxity and functional benefit. We performed upright, weight-bearing MR scans of both knees in the sagittal plane at different angles of flexion to determine the kinematics of the knee following unilateral reconstruction (n = 12). The uninjured knee acted as a control. Scans were performed pre-operatively and at three and six months post-operatively. Anteroposterior tibial laxity was determined using an arthrometer and patient function by validated questionnaires before and after reconstruction. In all the knees with deficient anterior cruciate ligaments, the tibial plateau was displaced anteriorly and internally rotated relative to the femur when compared with the control contralateral knee, particularly in extension and early flexion (mean lateral compartment displacement: extension 7.9 mm (sd 4.8), p = 0.002 and 30° flexion 5.1 mm (sd 3.6), p = 0.004). In all ten patients underwent post-operative scans. Reconstruction reduced the subluxation of the lateral tibial plateau at three months, with resolution of anterior displacement in early flexion, but not in extension (p = 0.015). At six months, the reconstructed knee again showed anterior subluxation in both the lateral (mean: extension 4.2 mm (sd 4.2), p = 0.021 and 30° flexion 3.2 mm (sd 3.3), p = 0.024) and medial compartments (extension, p = 0.049). Our results show that despite improvement in laxity and functional benefit, abnormal knee kinematics remain at six months and actually deteriorate from three to six months following reconstruction of the anterior cruciate ligament. PMID:21969431

  20. Single-Bundle Anterior Cruciate Ligament Reconstruction with Semitendinosus Tendon Using the PINN-ACL CrossPin System: Minimum 4-Year Follow-up

    PubMed Central

    Baek, Seung-Gil; Lee, Byoung-Joo; Lee, Chang-Hwa

    2015-01-01

    Purpose This study evaluated mid-term results of anterior cruciate ligament (ACL) reconstruction using the PINN-ACL CrossPin system that allowed for short graft fixation. Materials and Methods Forty-three patients underwent single-bundle ACL reconstruction with a 4-strand semitendinosus tendon graft using the PINN-ACL CrossPin system. Femoral fixation was done using the PINN-ACL CrossPin system, and the tibial side was fixed with post-tie and a bioabsorbable interference screw. The mean follow-up period was 50 months. Evaluation was done using the Lachman test, pivot-shift test, International Knee Documentation Committee (IKDC) score and grade. Anterior displacement was assessed. Results There was improvement in the Lachman test and pivot-shift test at final follow-up, form grade II (n=40) or III (n=3) to grade I (n=3) or 0 (n=40) and from grade I (n=20) or II (n=10) to grade I (n=8) or 0 (n=22), respectively. The mean IKDC score was 88.7, and grade A and B were 93.0% at final follow-up. Side-to-side difference was improved from 6.7 mm to 2.1 mm at final follow-up. Complications occurred in 3 patients, a re-ruptured due to trauma at 2 years after surgery and a deep infection and a superficial infection. Conclusions The mid-term follow-up results of ACL reconstruction with the PINN-ACL CrossPin system were satisfactory. The PINN-ACL CrossPin can be considered as a useful instrument for short graft fixation. PMID:25750893

  1. Septal and Anterior Reverse Mismatch of Myocardial Perfusion and Metabolism in Patients With Coronary Artery Disease and Left Bundle Branch Block

    PubMed Central

    Wang, Jian-Guang; Fang, Wei; Yang, Min-Fu; Tian, Yue-Qin; Zhang, Xiao-Li; Shen, Rui; Sun, Xiao-Xin; Guo, Feng; Wang, Dao-Yu; He, Zuo-Xiang

    2015-01-01

    Abstract The effects of left bundle branch block (LBBB) on left ventricular myocardial metabolism have not been well investigated. This study evaluated these effects in patients with coronary artery disease (CAD). Sixty-five CAD patients with complete LBBB (mean age, 61.8 ± 9.7 years) and 65 without LBBB (mean age, 59.9 ± 8.4 years) underwent single photon emission computed tomography, positron emission tomography, and contrast coronary angiography. The relationship between myocardial perfusion and metabolism and reverse mismatch score, and that between QRS length and reverse mismatch score and wall motion score were evaluated. The incidence of left ventricular septum and anterior wall reverse mismatching between the two groups was significantly different (P < 0.001 and P = 0.002, respectively). The incidences of normal myocardial perfusion and metabolism in the left ventricular lateral and inferior walls were also significantly different between the two groups (P < 0.001 and P < 0.001, respectively). The incidence of septal reverse mismatching in patients with mild to moderate perfusion was significantly higher among those with LBBB than among those without LBBB (P < 0.001). In CAD patients with LBBB, septal reverse mismatching was significantly more common among those with mild to moderate perfusion than among those with severe perfusion defects (P = 0.002). The correlation between the septal reverse mismatch score and QRS length was significant (P = 0.026). In patients with CAD and LBBB, septal and anterior reverse mismatching of myocardial perfusion and metabolism was frequently present; the septal reverse mismatch score negatively correlated with the QRS interval. PMID:25997045

  2. Double-blind clinical trial of topical steroids in anterior uveitis.

    PubMed Central

    Dunne, J A; Travers, J P

    1979-01-01

    We present the results of a double-blind trial comparing the efficacy of betamethasone phosphate 0.1%, clobetasone butyrate 0.1%, and placebo in the treatment of acute unilateral nongranulomatous uveitis. The 2 steroids were equally comparable in improvement of the patients' symptoms, though betamethasone phosphate was significantly more effective than clobetasone butyrate in improving the ocular signs of uveitis. However, clobetasone butyrate had significantly less effect on raising intraocular pressure in known steroid responders and ocular hypertensives than did dexamethasone. The use of a bolometer as an objective measure in uveitis was significant only in the more severe cases of uveitis. In comparing the placebo group of patients with those on topical steroids, the former group, though improving, appeared to lag behind by approximately one week. Four cases on placebo, however, had to be withdrawn because of worsening of the condition. Mild cases of anterior uveitis would probably resolve without using topical steroids. PMID:389282

  3. Coracoclavicular ligament reconstruction: biomechanical comparison of tendon graft repairs to a synthetic double bundle augmentation.

    PubMed

    Wellmann, Mathias; Kempka, Jan P; Schanz, Steffen; Zantop, Thore; Waizy, Hazibullah; Raschke, Michael J; Petersen, Wolf

    2009-05-01

    For currently presented anatomical coracoclavicular ligament repairs issues such as autologous tendon graft versus synthetic suture augmentation and the optimum fixation strategies for both types of reconstruction are not solved. The purpose of the study was to compare the biomechanical properties of different tendon graft repairs to the characteristics of a synthetic polyester augmentation. Four anatomical coracoclavicular ligament repairs were biomechanically tested: 5 mm coracoclavicular tendon loop with suture fixation, tendon loop with flip button fixation, tendon loop with interference screw fixation versus a double 1.0-mm polyester repair with flip button fixation. The biomechanical testing included cyclic superio-inferior loading and a subsequent load to failure protocol. The ultimate failure loads were significantly higher for the double polyester/flip button repair (927 N) compared to all tendon repair techniques (maximum 640 N). In contrast the stiffness level was higher for the tendon repairs compared to the polyester/flip button repair (68.7 N/mm) but strongly dependent on the fixation technique (interference screw 97.2 N/mm, flip button 84.9 N/mm, side to side suture 60.9 N/mm). A synthetic coracoclavicular augmentation using a polyester suture provides adequate structural properties compared to a tendon repair. Therefore the decision for a tendon graft should be made by the necessity of a biologic substrate rather than by the assumption of a biomechanical advantage. PMID:19225755

  4. Anatomic Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Murawski, Christopher D.; Wolf, Megan R.; Araki, Daisuke; Muller, Bart; Tashman, Scott

    2013-01-01

    Anatomic anterior cruciate ligament (ACL) reconstruction is common procedure performed by orthopedic surgeons, particularly in association with sports-related injuries. Whereas traditional reconstruction techniques used a single bundle graft that was typically placed in a non-anatomic position, a renewed interest in anatomy has facilitated the popularization of anatomic reconstruction techniques. Recently, a focus has been placed on individualizing ACL surgery based on each patient’s native anatomical characteristics (e.g., insertion site size, notch size, and shape), thereby dictating the ultimate procedure of choice. As subjective outcome measurements have demonstrated varying outcomes with respect to single- versus double-bundle ACL reconstruction, investigators have turned to more objective techniques, such as in vivo kinematics, as a means of evaluating joint motion and cartilage contact mechanics. Further investigation in this area may yield important information with regard to the potential progression to osteoarthritis after ACL reconstruction, including factors affecting or preventing it. PMID:26069663

  5. Double Dissociation Between Action-driven and Perception-driven Conflict Resolution Invoking Anterior versus Posterior Brain Systems

    PubMed Central

    Schulte, Tilman; Müller-Oehring, Eva M.; Vinco, Shara; Hoeft, Fumiko; Pfefferbaum, Adolf; Sullivan, Edith V.

    2009-01-01

    The ability to select and integrate relevant information in the presence of competing irrelevant information can be enhanced by advance information to direct attention and guide response selection. Attentional preparation can reduce perceptual and response conflict, yet little is known about the neural source of conflict resolution, whether it is resolved by modulating neural responses for perceptual selection to emphasize task-relevant information or for action selection to inhibit pre-potent responses to interfering information. We manipulated perceptual information that either matched or did not match the relevant color feature of an upcoming Stroop stimulus and recorded hemodynamic brain responses to these events. Longer reaction times to incongruent than congruent color-word Stroop stimuli indicated conflict; however, conflict was even greater when a color cue correctly predicted the Stroop target’s color (match) than when it did not (nonmatch). A predominantly anterior network was activated for Stroop-match and a predominantly posterior network was activated for Stroop-nonmatch. Thus, when a stimulus feature did not match the expected feature, a perceptually-driven posterior attention system was engaged, whereas when interfering, automatically-processed semantic information required inhibition of pre-potent responses, an action-driven anterior control system was engaged. These findings show a double dissociation of anterior and posterior cortical systems engaging in different types of control for perceptually-driven and action-driven conflict resolution. PMID:19573610

  6. Reliability of Single-leg and Double-leg Balance Tests in Subjects with Anterior Cruciate Ligament Reconstruction and Controls.

    PubMed

    Kouvelioti, Vasiliki; Kellis, Eleftherios; Kofotolis, Nikolaos; Amiridis, Ioannis

    2015-01-01

    The purpose of this study was to assess the test-retest reliability of postural balance in patients with anterior cruciate ligament reconstruction (ACL) and controls. Ten healthy subjects and 15 individuals with ACL reconstruction performed single-leg and double-leg balance tests. The center of pressure (COP) was recorded using a pressure platform. For the total COP path, the intraclass correlation coefficient (ICC) ranged from 0.79 to 0.91. For the COP standard deviation, the ICCs ranged from 0.68 to 0.94. For the COP velocity, the ICCs ranged from 0.72 to 0.91. The sway area and ellipse scores displayed ICCs values of 0.67 to 0.95 and 0.53 to 0.92, respectively. The ICCs were higher for double leg tests compared with single-stance ones. These results indicate that 30 s balance tests in double and single-leg stance are reliable tools to assess static balance. The use of such tests to monitor rehabilitation programs following ACL reconstruction is recommended. PMID:25649642

  7. Preoperative, intraoperative and postoperative risk factors for anastomotic leakage after laparoscopic low anterior resection with double stapling technique anastomosis

    PubMed Central

    Kawada, Kenji; Sakai, Yoshiharu

    2016-01-01

    Anastomotic leakage (AL) is one of the most devastating complications after rectal cancer surgery. The double stapling technique has greatly facilitated intestinal reconstruction especially for anastomosis after low anterior resection (LAR). Risk factor analyses for AL after open LAR have been widely reported. However, a few studies have analyzed the risk factors for AL after laparoscopic LAR. Laparoscopic rectal surgery provides an excellent operative field in a narrow pelvic space, and enables total mesorectal excision surgery and preservation of the autonomic nervous system with greater precision. However, rectal transection using a laparoscopic linear stapler is relatively difficult compared with open surgery because of the width and limited performance of the linear stapler. Moreover, laparoscopic LAR exhibits a different postoperative course compared with open LAR, which suggests that the risk factors for AL after laparoscopic LAR may also differ from those after open LAR. In this review, we will discuss the risk factors for AL after laparoscopic LAR. PMID:27433085

  8. The Anterior Double-Tilt Precision Attachment Case for Cleft Palate Patients and Accident Victims. Case Reports.

    PubMed

    Feinberg, Edward

    2016-01-01

    Passively retained precision attachment removable partial dentures have been used successfully since the 1920s. Adult cleft palate patients and accident victims often have endured a lifetime of wearing awkward appliances to replace the missing structures that never formed intraorally or were lost in a traumatic accident. These patients tend to be poor candidates for dental implants, even with repeated grafting surgeries. The anterior double-tilt precision attachment case is a great treatment option for adults to restore the missing dental structures. Anterior precision partial dentures are stable appliances in the mouth that are worn 24 hours a day and only removed for hygiene. They can be custom designed for maximum esthetics. They do not require denture paste, and they extend minimally onto the palate. As a result, they do not interfere with musculature, tongue movements, speech and taste. Cleft palate patients and accident victims with poor or non-existent edentulous ridges will have difficulty retaining a denture, so preservation of the existing dentition is essential for comfort and function. Because these prostheses do not apply destructive forces to the abutment teeth, they can last decades with minimal maintenance. PMID:26939155

  9. Factors Predicting Difficulty of Laparoscopic Low Anterior Resection for Rectal Cancer with Total Mesorectal Excision and Double Stapling Technique

    PubMed Central

    Chen, Weiping; Li, Qiken; Fan, Yongtian; Li, Dechuan; Jiang, Lai; Qiu, Pengnian; Tang, Lilong

    2016-01-01

    Background Laparoscopic sphincter-preserving low anterior resection for rectal cancer is a surgery demanding great skill. Immense efforts have been devoted to identifying factors that can predict operative difficulty, but the results are inconsistent. Objective Our study was conducted to screen patients’ factors to build models for predicting the operative difficulty using well controlled data. Method We retrospectively reviewed records of 199 consecutive patients who had rectal cancers 5–8 cm from the anal verge. All underwent laparoscopic sphincter-preserving low anterior resections with total mesorectal excision (TME) and double stapling technique (DST). Data of 155 patients from one surgeon were utilized to build models to predict standardized endpoints (operative time, blood loss) and postoperative morbidity. Data of 44 patients from other surgeons were used to test the predictability of the built models. Results Our results showed prior abdominal surgery, preoperative chemoradiotherapy, tumor distance to anal verge, interspinous distance, and BMI were predictors for the standardized operative times. Gender and tumor maximum diameter were related to the standardized blood loss. Temporary diversion and tumor diameter were predictors for postoperative morbidity. The model constructed for the operative time demonstrated excellent predictability for patients from different surgeons. Conclusions With a well-controlled patient population, we have built a predictable model to estimate operative difficulty. The standardized operative time will make it possible to significantly increase sample size and build more reliable models to predict operative difficulty for clinical use. PMID:26992004

  10. Surgical treatment of simultaneous rupture of the anterior cruciate ligament and the patellar tendon.

    PubMed

    Chiba, Kyohei; Takahashi, Toshiaki; Hino, Kazunori; Watanabe, Seiji; Yamaoka, Gotaro; Shirakata, Haruo; Fujii, Yuko; Miura, Hiromasa

    2013-12-01

    Although the rupture of the anterior cruciate ligament (ACL) is a common sports injury, a simultaneous rupture of the patellar tendon (PT) is relatively rare. We experienced a case in which a patient simultaneously ruptured the ACL, the medial collateral ligament (MCL), and the PT while sliding during a baseball game. We sutured the PT and MCL during the acute stage, and 7 months later we conducted a double-bundle reconstruction of the ACL. To our knowledge, this is the first report of PT repair using only fiber wire thread, and two-phase double-bundle ACL reconstruction. PMID:23288727

  11. Double layer repair of tibialis anterior muscle hernia in a soccer player: a case report and review of the literature

    PubMed Central

    Dönmez, Gürhan; Evrenos, Mustafa Kürsat; Cereb, Meryem; Karanfil, Yigitcan; Doral, Mahmut Nedim

    2015-01-01

    Summary Background muscle herniations usually present in athletes especially in the lower legs; occurring through defects in the deep fascial layer of the muscles and typically seen following local blunt trauma or muscle hypertrophy after strenuous exercise. Management of muscle hernias varies from conservative therapy to surgical repair and usually needs multidisciplinary collaboration for differential diagnosis. Methods herein tibialis anterior muscle hernia in 17-year-old male soccer player was presented. The diagnosis was confirmed with dynamic ultrasonographic views changing with the different movements of the ankle. Since the symptoms were not relieved with conservative methods, surgical repair of the defect was offered. Results we preferred to repair fascial defect with double layer and Mesh graft that were placed over primary suture repair. No complications were reported such as wound or mesh infection postoperatively. The patient was clinically satisfied and returned his previous activity level after 3 months of surgery. After 2 years of follow-up the feature of the bulge was dissolved and player was satisfied with the operation. Conclusion knowledge of the lower extremity muscle herniation is essential for both proper management and/or surgical referral. The importance of protective devices in prevention, dynamic ultrasonography in diagnosis and double layer repair of the fascial defect with Mesh graft in treatment of muscle herniations were highlighted. PMID:26958545

  12. [Masquerading bundle branch block].

    PubMed

    Kukla, Piotr; Baranchuk, Adrian; Jastrzębski, Marek; Bryniarski, Leszek

    2014-01-01

    We here describe a surface 12-lead electrocardiogram (ECG) of a 72-year-old female with a prior history of breast cancer and chemotherapy-induced cardiomyopathy. An echocardiogram revealed left ventricular dysfunction, ejection fraction of 23%, with mild enlarged left ventricle. The 12-lead ECG showed atrial fibrillation with a mean heart rate of about 100 bpm, QRS duration 160 ms, QT interval 400 ms, right bundle branch block (RBBB) and left anterior fascicular block (LAFB). The combination of RBBB features in the precordial leads and LAFB features in the limb leads is known as ''masquerading bundle branch block''. In most cases of RBBB and LAFB, the QRS axis deviation is located between - 80 to -120 degrees. Rarely, when predominant left ventricular forces are present, the QRS axis deviation is near about -90 degrees, turning the pattern into an atypical form. In a situation of RBBB associated with LAFB, the S wave can be absent or very small in lead I. Such a situation is the result of not only purely LAFB but also with left ventricular hypertrophy and/or focal block due to scar (extensive anterior myocardial infarction) or fibrosis (cardiomyopathy). Sometimes, this specific ECG pattern is mistaken for LBBB. RBBB with LAFB may imitate LBBB either in the limb leads (known as 'standard masquerading' - absence of S wave in lead I), or in the precordial leads (called 'precordial masquerading' - absence of S wave in leads V₅ and V₆). Our ECG showed both these types of masquerading bundle branch block - absence of S wave in lead I and in leads V₅ and V₆. PMID:24469750

  13. Lower extremity muscle activation onset times during the transition from double-leg stance to single-leg stance in anterior cruciate ligament injured subjects.

    PubMed

    Dingenen, Bart; Janssens, Luc; Luyckx, Thomas; Claes, Steven; Bellemans, Johan; Staes, Filip F

    2015-12-01

    The goal of this study was to evaluate muscle activation onset times (MAOT) of both legs during a transition task from double-leg stance (DLS) to single-leg stance (SLS) in anterior cruciate ligament injured (ACLI) (n=15) and non-injured control subjects (n=15) with eyes open and eyes closed. Significantly delayed MAOT were found in the ACLI group compared to the control group for vastus lateralis, vastus medialis obliquus, hamstrings medial, hamstrings lateral, tibialis anterior, peroneus longus and gastrocnemius in both vision conditions, for gluteus maximus and gluteus medius with eyes open and for tensor fascia latae with eyes closed. Within the ACLI group, delayed MAOT of tibialis anterior with eyes open and gastrocnemius with eyes closed were found in the injured leg compared to the non-injured leg. All other muscles were not significantly different between legs. In conclusion, the ACLI group showed delayed MAOT not only around the knee, but also at the hip and ankle muscles compared to the non-injured control group. No differences between both legs of the ACLI group were found, except for tibialis anterior and gastrocnemius. These findings indirectly support including central nervous system re-education training to target the underlying mechanisms of these altered MAOT after ACL injury. PMID:26409102

  14. Functional Outcomes of Primary Anterior Cruciate Ligament Reconstruction with Tibialis Anterior Allograft

    PubMed Central

    Başar, Selda; Büyükafşar, Enes; Hazar, Zeynep; Ataoğlu, Baybars; Kanatlı, Ulunay

    2014-01-01

    Objectives: Allografts have potential advantages in primary anterior cruciate ligament reconstruction (ACLR), including the absence of donor site morbidity, shorter operative times, improved cosmesis, and easier rehabilitation. There is limited and conflicting outcome data for ACLR with tibialis anterior allograft. The purpose of this study was to evaluate the functional outcomes of ACLR with tibialis anterior allograft. Methods: We retrospectively evaluated patients underwent ACLR using with tibialis anterior allograft between 2005 and 2013. Totally 12 patients who were performed suspensory fixation technique were included in this study (range: 25-43 years). Exclusion criteria included double bundle, bone tendon bone technique and revision surgery. Clinical outcomes were measured by subject part of International Knee Documentation Committee (IKDC) and Lysholm scores. Results: A significant increase was reported in all the clinical scores. In particular, the IKDC-subjective score increased from a basal value of 45.5±12.7 to 84.3±5.50 at the 12 months' evaluation (p<0.05). The Lysholm score revealed a significant improvement from 49.7±14.2 to 83.5±20.5 at the 12 months' evaluation (p<0.05). Conclusion: ACLR with tibialis anterior allograft is an effective treatment for correcting loss of function and increasing quality of life.

  15. Visualization of Kent bundle position in WPW syndrome using phase analysis

    SciTech Connect

    Nishimura, Y.; Yamamuro, M.; Konishi, T.; Nakano, T.; Takezawa, H.

    1985-05-01

    Multigated blood pool scintigraphy was performed in 20 normal subjects and 20 patients with WPW syndrome. Cardiac imaging was performed in left anterior oblique, right anterior oblique, and left lateral views. In 8 patients with WPW syndrome, gated single photon emission computed tomography (SPECT) was also done. Regional ventricular contraction patterns were evaluated with sequential regional phase mapping. In WPW syndrome, abnormal earlier contraction site could detect at affected ventricular base just below the atrium not seen in normal cases. In three cases double bypass tracts were seen. These abnormal contraction sites were disappeared after blocked conduction with procainamide or surgery. SPECT images were the most reliable to verify the exact position of abnormal contraction sites especially at posterior wall. The authors confirm Kent bundle position in WPW syndrome in 19 cases and conclude: multiprojection or SPECT phase image was suitable method to identify exact position of accessory bypass tract noninvasively; routine left anterior oblique view was not useful position for WPW syndrome.

  16. A multi-scale structural study of the porcine anterior cruciate ligament tibial enthesis

    PubMed Central

    Zhao, Lei; Thambyah, Ashvin; Broom, Neil D

    2014-01-01

    Like the human anterior cruciate ligament (ACL), the porcine ACL also has a double bundle structure and several biomechanical studies using this model have been carried out to show the differential effect of these two bundles on macro-level knee joint function. It is hypothesised that if the different bundles of the porcine ACL are mechanically distinct in function, then a multi-scale anatomical characterisation of their individual enthesis will also reveal significant differences in structure between the bundles. Twenty-two porcine knee joints were cleared of their musculature to expose the intact ACL following which ligament–bone samples were obtained. The samples were fixed in formalin followed by decalcification with formic acid. Thin sections containing the ligament insertion into the tibia were then obtained by cryosectioning and analysed using differential interference contrast (DIC) optical microscopy and scanning electron microscopy (SEM). At the micro-level, the anteromedial (AM) bundle insertion at the tibia displayed a significant deep-rooted interdigitation into bone, while for the posterolateral (PL) bundle the fibre insertions were less distributed and more focal. Three sub-types of enthesis were identified in the ACL and related to (i) bundle type, (ii) positional aspect within the insertion, and (iii) specific bundle function. At the nano-level the fibrils of the AM bundle were significantly larger than those in the PL bundle. The modes by which the AM and PL fibrils merged with the bone matrix fibrils were significantly different. A biomechanical interpretation of the data suggests that the porcine ACL enthesis is a specialized, functionally graded structural continuum, adapted at the micro-to-nano scales to serve joint function at the macro level. PMID:24697495

  17. Anterior Cruciate Ligament Reconstruction in Patients with Generalized Joint Laxity

    PubMed Central

    Kim, Sung-Jae; Kumar, Praveen

    2010-01-01

    Generalized joint laxity is a genetically determined component of overall joint flexibility. The incidence of joint laxity in the overall population is approximately 5% to 20%, and its prevalence is higher in females. Recently it was noticed that individuals with generalized joint laxity are not only prone to anterior cruciate ligament injuries but also have inferior results after a reconstruction. Therefore, an anterior cruciate ligament reconstruction in patients with generalized laxity should be undertaken with caution due to the higher expected failure rate from the complexity of problems associated with this condition. It is also necessary to identify the risk factors for the injury as well as for the post operative outcome in this population. A criterion that includes all the associated components is necessary for the proper screening of individuals for generalized joint laxity. Graft selection for an anterior cruciate reconstruction in patients with ligament laxity is a challenge. According to the senior author, a hamstring autograft is an inferior choice and a double bundle reconstruction with a quadriceps tendon-bone autograft yields better results than a single bundle bone-patella tendon-bone autograft. Future studies comparing the different grafts available might be needed to determine the preferred graft for this subset of patients. Improved results after an anterior cruciate ligament reconstruction can be achieved by proper planning and careful attention to each step beginning from the clinical examination to the postoperative rehabilitation. PMID:20808583

  18. Anatomical reconstruction of the anterior cruciate ligament: a logical approach

    PubMed Central

    Gali, Julio Cesar

    2015-01-01

    We describe the surgical approach that we have used over the last years for anterior cruciate ligament (ACL) reconstruction, highlighting the importance of arthroscopic viewing through the anteromedial portal (AMP) and femoral tunnel drilling through an accessory anteromedial portal (AMP). The AMP allows direct view of the ACL femoral insertion site on the medial aspect of the lateral femoral condyle, does not require guides for anatomic femoral tunnel reaming, prevents an additional lateral incision in the distal third of the thigh (as would be unavoidable when the outside-in technique is used) and also can be used for double-bundle ACL reconstruction. PMID:26417571

  19. Maintaining endotracheal tube cuff pressure at 20 mm Hg to prevent dysphagia after anterior cervical spine surgery; protocol of a double-blind randomised controlled trial

    PubMed Central

    2013-01-01

    Background In anterior cervical spine surgery a retractor is obligatory to approach the spine. Previous studies showed an increase of endotracheal tube cuff pressure after placement of a retractor. It is known that high endotracheal tube cuff pressure increases the incidence of postoperative dysphagia, hoarseness, and sore throat. However, until now no evidence supports the fact whether adjusting the endotracheal tube cuff pressure during anterior cervical spine surgery will prevent this comorbidity. We present the design of a randomized controlled trial to determine whether adjusting endotracheal tube cuff pressure after placement of a retractor during anterior cervical spine surgery will prevent postoperative dysphagia. Methods/design 177 patients (aged 18–90 years) scheduled for anterior cervical spine surgery on 1 or more levels will be included. After intubation, endotracheal tube cuff pressure is manually inflated to 20 mm Hg in all patients. Patients will be randomized into two groups. In the control group endotracheal tube cuff pressure is not adjusted after retractor placement. In the intervention group endotracheal tube cuff pressure after retractor placement is maintained at 20 mm Hg and air is withdrawn when cuff pressure exceeds 20 mm Hg. Endotracheal tube cuff pressure is measured after intubation, before and after placement and removal of the retractor. Again air is inflated if cuff pressure sets below 20 mmHg after removal of the retractor. The primary outcome measure is postoperative dysphagia. Other outcome measures are postoperative hoarseness, postoperative sore throat, degree of dysphagia, length of hospital stay, and pneumonia. The study is a single centre double blind randomized trial in which patients and research nurses will be kept blinded for the allocated treatment during the follow-up period of 2 months. Discussion Postoperative dysphagia occurs frequently after anterior cervical spine surgery. This may be related to high

  20. Comparing Single Versus Double Screw-Rod Anterior Instrumentation for Treating Thoracolumbar Burst Fractures with Incomplete Neurological Deficit: A Prospective, Randomized Controlled Trial.

    PubMed

    Yu, Yu; Wang, Juan; Shao, Gaohai; Wang, Qunbo; Li, Bo

    2016-01-01

    BACKGROUND Following a thoracolumbar burst fracture (TCBF), anterior screw-rods apply pressure upon the graft site. However, there is limited evidence comparing single screw-rod anterior instrumentation (SSRAI) to double screw-rod anterior instrumentation (DSRAI) for TCBFs. Our objective was to compare SSRAI versus DSRAI for TCBFs with incomplete neurological deficit. MATERIAL AND METHODS A total of 51 participants with T11-L2 TCBFs (AO classification: A3) were randomly assigned to receive SSRAI or DSRAI. Key preoperative, perioperative, and postoperative data were collected. Statistical analysis was conducted to determine the independent factors associated with inferior clinical outcomes, as well as the comparative efficacy of SSRAI and DSRAI. RESULTS There were no significant differences in the key demographic and clinical characteristics between the two groups (all p>0.05). Smoking status was significantly associated with inferior three-month and six-month Denis pain scores (Wald statistic=4.246, p=0.039). Both SSRAI and DSRAI were significantly effective in improving three-month and six-month postoperative degree of kyphosis, three-month and six-month postoperative ASIA impairment scale scores, three-month and six-month postoperative Denis pain score, and three-month and six-month postoperative Denis work score (all p<0.001). Although there were no significant differences between DSRAI and SSRAI with respect to all outcomes (all p>0.05), DSRAI displayed significantly longer operating times, as well as significantly larger operative blood losses (both p<0.001). CONCLUSIONS SSRAI may be preferable over DSRAI for TCBFs with incomplete neurological deficit due to its lower operating time and amount of operative blood loss. PMID:27197020

  1. Comparing Single Versus Double Screw-Rod Anterior Instrumentation for Treating Thoracolumbar Burst Fractures with Incomplete Neurological Deficit: A Prospective, Randomized Controlled Trial

    PubMed Central

    Yu, Yu; Wang, Juan; Shao, Gaohai; Wang, Qunbo; Li, Bo

    2016-01-01

    Background Following a thoracolumbar burst fracture (TCBF), anterior screw-rods apply pressure upon the graft site. However, there is limited evidence comparing single screw-rod anterior instrumentation (SSRAI) to double screw-rod anterior instrumentation (DSRAI) for TCBFs. Our objective was to compare SSRAI versus DSRAI for TCBFs with incomplete neurological deficit. Material/Methods A total of 51 participants with T11-L2 TCBFs (AO classification: A3) were randomly assigned to receive SSRAI or DSRAI. Key preoperative, perioperative, and postoperative data were collected. Statistical analysis was conducted to determine the independent factors associated with inferior clinical outcomes, as well as the comparative efficacy of SSRAI and DSRAI. Results There were no significant differences in the key demographic and clinical characteristics between the two groups (all p>0.05). Smoking status was significantly associated with inferior three-month and six-month Denis pain scores (Wald statistic=4.246, p=0.039). Both SSRAI and DSRAI were significantly effective in improving three-month and six-month postoperative degree of kyphosis, three-month and six-month postoperative ASIA impairment scale scores, three-month and six-month postoperative Denis pain score, and three-month and six-month postoperative Denis work score (all p<0.001). Although there were no significant differences between DSRAI and SSRAI with respect to all outcomes (all p>0.05), DSRAI displayed significantly longer operating times, as well as significantly larger operative blood losses (both p<0.001). Conclusions SSRAI may be preferable over DSRAI for TCBFs with incomplete neurological deficit due to its lower operating time and amount of operative blood loss. PMID:27197020

  2. Anatomic Tunnel Placement in Anterior Cruciate Ligament Reconstruction.

    PubMed

    Dhawan, Aman; Gallo, Robert A; Lynch, Scott A

    2016-07-01

    The anatomic anterior cruciate ligament (ACL) reconstruction concept has developed in part from renewed interest in the insertional anatomy of the ACL, using surgical techniques that can reproduce this anatomy reliably and accurately during surgical reconstruction. Several technical tools are available to help identify and place the tibial and femoral grafts anatomically, including arthroscopic anatomic landmarks, a malleable ruler device, and intraoperative fluoroscopy. The changes in technique for anatomic tunnel placement in ACL reconstruction follow recent biomechanical and kinematic data that demonstrate improved time zero characteristics. A better re-creation of native ACL kinematics and biomechanics is achieved with independent femoral drilling techniques that re-create a central footprint single-bundle ACL reconstruction or double-bundle reconstruction. However, to date, limited short-term and long-term clinical outcome data have been reported that support using either of these techniques rather than a transtibial drilling technique. This lack of clear clinical advantage for femoral independent and/or double-bundle techniques may arise because of the potentially offsetting biologic incorporation challenges of these grafts when placed using these techniques or could result from modifications made in traditional endoscopic transtibial techniques that allow improved femoral and tibial footprint restoration. PMID:27243794

  3. His bundle electrography

    MedlinePlus

    ... can be given medicines during the test. Electrocardiogram (ECG) leads are placed on your arms and legs. ... HBE; His bundle recording; Electrogram - His bundle Images ECG References Miller JM, Zipes DP. Diagnosis of cardiac ...

  4. Case report: Double nerve transfer of the anterior and posterior interosseous nerves to treat a high ulnar nerve defect at the elbow.

    PubMed

    Delclaux, S; Aprédoaei, C; Mansat, P; Rongières, M; Bonnevialle, P

    2014-10-01

    Double neurotization of the deep branch of ulnar nerve (DBUN) and superficial branch of ulnar nerve using the anterior interosseous nerve (AIN) and the recurrent (thenar) branch of the median nerve was first described by Battiston and Lanzetta. This article details the postoperative results after 18 months of a patient who underwent this technique using the posterior interosseous nerve (PIN) instead of the recurrent branch of the median nerve for sensory reconstruction. A 35-year-old, right-handed man suffered major trauma to his right upper limb following a serious motor vehicle accident. One year later, a pseudocystic neuroma of the ulnar nerve was evident on ultrasound examination and MRI. After the neuroma had been resected, the nerve defect was estimated at 8 cm. One and a half years after the initial trauma, with the patient still at M0/S0, we transferred the AIN and PIN onto the deep and superficial branches of the ulnar nerve respectively. Nerve recovery was monitored clinically every month and by electromyography (EMG) every three months initially and then every six months. At 18 months postoperative, 5th digit abduction/adduction was 28 mm. Sensation was present at the base of the 5th digit. The patient was graded M3/S2. Clear re-innervation of the abductor digiti minimi was demonstrated by EMG (motor conduction velocity 50 m/s). Given that the ulnar nerve could not be excited at the elbow, this re-innervation had to be the result of the double nerve transfer. Neurotization of the DBUN using the AIN produces functional results as early as 1 year after surgery. Using PIN for sensory neurotization is easy to perform, has no negative consequences for the donor site, and leads to good recovery of sensation (graded as S2) after 18 months. PMID:25260763

  5. Femoral nerve block versus adductor canal block for postoperative pain control after anterior cruciate ligament reconstruction: A randomized controlled double blind study

    PubMed Central

    El Ahl, Mohamed Sayed

    2015-01-01

    Background: The objective of this study was to evaluate the reliability of the postoperative pain control using adductor canal block (ACB) compared that using the femoral nerve block (FNB) in patients with anterior cruciate ligament reconstructions (ACLR). Materials and methods: One hundred and twenty-eight patients who had been scheduled to patellar graft ACLR were included in this double blind study, and were randomly allocated into two groups; group ACB and group FNB (64 patients each). All patients received general anesthesia. At the end of the surgery, patients in group FNB received a FNB and those in group ACB received an ACB. The postoperative pain (visual analog scale [VAS]) and muscle weakness were assessed in the postoperative care unit and every 6 h thereafter for 24 h. The total morphine requirements were also recorded. Results: Patients in group ACB had significantly higher VAS (at 18 h and 24 h), higher morphine consumption, but significantly less quadriceps weakness than those in group FNB. Conclusion: In patients with patellar graft ACLR, the ACB can maintain a higher quadriceps power, but with lesser analgesia compared with the FNB. PMID:26240546

  6. Postural stability deficits during the transition from double-leg stance to single-leg stance in anterior cruciate ligament reconstructed subjects.

    PubMed

    Dingenen, Bart; Janssens, Luc; Claes, Steven; Bellemans, Johan; Staes, Filip F

    2015-06-01

    The goal of this study was to evaluate postural stability during the transition from double-leg stance (DLS) to single-leg stance (SLS) in anterior cruciate ligament reconstructed (ACLR) (n=20) and non-injured control subjects (n=20). All ACLR subjects had fully returned to their pre-injury sport participation. Both groups were similar for age, gender, height, weight, body mass index and activity level. Spatiotemporal center of pressure outcomes of both legs of each subject were measured during the transition from DLS to SLS in eyes open and eyes closed conditions. Movement speed was standardized. The center of pressure displacement after a new stability point was reached during the SLS phase was significantly increased in the ACLR group compared to the control group in the eyes closed condition (P=.001). No significant different postural stability outcomes were found between the operated and non-operated legs. In conclusion, the ACLR group showed postural stability deficits, indicating that these persons may have a decreased ability to stabilize their body after the internal postural perturbation created by the transition from DLS to SLS. The non-operated leg may not be the best reference when evaluating postural stability of the operated leg after ACLR, as no differences were found between legs. PMID:25744596

  7. Bilateral Medial Tibial Plateau Fracture after Arthroscopic Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Cho, Chul Hyun; Lee, Kyung Jae; Jeon, Jong Hyuk

    2015-01-01

    Tibial plateau fractures after arthroscopic anterior cruciate ligament (ACL) reconstruction are rare, and only isolated cases have been reported. The authors describe a case of bilateral medial tibial plateau fracture following a minor motorcycle accident in a patient who underwent arthroscopic ACL reconstruction in the past. Two years and four months before the accident, the patient underwent an arthroscopically assisted ACL reconstruction using double-bundle technique on his left knee at a hospital. He had the same surgery using single-bundle technique on his right knee about eight months ago at another hospital. The fractures in his both involved knees occurred through the tibial tunnel and required open reduction with internal fixation. At three weeks after fixation, a second-look arthroscopy revealed intact ACLs in both knees. At five months follow-up, he was able to walk without instability on physical examination. Follow-up radiographs of the patient showed callus formations with healed fractures. PMID:26060613

  8. Current Trends in Anterior Cruciate Ligament Reconstruction: A Review.

    PubMed

    Vaishya, Raju; Agarwal, Amit Kumar; Ingole, Sachin; Vijay, Vipul

    2015-01-01

    Anterior cruciate ligament reconstruction (ACLR) is an accepted and established surgical technique for anterior cruciate ligament (ACL) injuries and is now being practiced across the globe in increasing numbers. Although most patients get good to excellent results in the short-term after ACLR, its consequences in the long-term in prevention or acceleration of knee osteoarthritis (OA) are not yet well-defined. Still, there are many debatable issues related to ACLR, such as the appropriate timing of surgery, graft selection, fixation methods of the graft, operative techniques, rehabilitation after surgery, and healing augmentation techniques. Most surgeons prefer not to wait long after an ACL injury to do an ACLR, as delayed reconstruction is associated with secondary damages to the intra- and periarticular structures of the knee. Autografts are the preferred choice of graft in primary ACLR, and hamstring tendons are the most popular amongst surgeons. Single bundle ACLR is being practiced by the majority, but double bundle ACLR is getting popular due to its theoretical advantage of providing more anatomical reconstruction. A preferred construct is the interference fixation (Bio-screw) at the tibial site and the suspensory method of fixation at the femoral site. In a single bundle hamstring graft, a transportal approach for creating a femoral tunnel has recently become more popular than the trans-tibial technique. Various healing augmentation techniques, including the platelet rich plasma (PRP), have been tried after ACLR, but there is still no conclusive proof of their efficacy. Accelerated rehabilitation is seemingly more accepted immediately after ACLR. PMID:26697280

  9. Current Trends in Anterior Cruciate Ligament Reconstruction: A Review

    PubMed Central

    Vaishya, Raju; Ingole, Sachin; Vijay, Vipul

    2015-01-01

    Anterior cruciate ligament reconstruction (ACLR) is an accepted and established surgical technique for anterior cruciate ligament (ACL) injuries and is now being practiced across the globe in increasing numbers. Although most patients get good to excellent results in the short-term after ACLR, its consequences in the long-term in prevention or acceleration of knee osteoarthritis (OA) are not yet well-defined. Still, there are many debatable issues related to ACLR, such as the appropriate timing of surgery, graft selection, fixation methods of the graft, operative techniques, rehabilitation after surgery, and healing augmentation techniques. Most surgeons prefer not to wait long after an ACL injury to do an ACLR, as delayed reconstruction is associated with secondary damages to the intra- and periarticular structures of the knee. Autografts are the preferred choice of graft in primary ACLR, and hamstring tendons are the most popular amongst surgeons. Single bundle ACLR is being practiced by the majority, but double bundle ACLR is getting popular due to its theoretical advantage of providing more anatomical reconstruction. A preferred construct is the interference fixation (Bio-screw) at the tibial site and the suspensory method of fixation at the femoral site. In a single bundle hamstring graft, a transportal approach for creating a femoral tunnel has recently become more popular than the trans-tibial technique. Various healing augmentation techniques, including the platelet rich plasma (PRP), have been tried after ACLR, but there is still no conclusive proof of their efficacy. Accelerated rehabilitation is seemingly more accepted immediately after ACLR. PMID:26697280

  10. Fiber bundle endocytoscopy

    PubMed Central

    Hughes, Michael; Chang, Tou Pin; Yang, Guang-Zhong

    2013-01-01

    Endocytoscopy is an optical biopsy technique which uses a miniaturized camera to capture white light microscopy images through an endoscope. We have developed an alternative design that instead relays images to an external camera via a coherent fiber bundle. In this paper we characterize the device and demonstrate microscopy of porcine tissue ex vivo. One advantage of our approach is the ease with which other bundle-compatible imaging modalities can be deployed simultaneously. We show this by acquiring quasi-simultaneous endocytoscopy and fluorescence confocal endomicroscopy images through a single fiber bundle. This opens up possibilities for multi-modal endomicroscopy, combining white light and fluorescence imaging. PMID:24409380

  11. MEGARA fiber bundles

    NASA Astrophysics Data System (ADS)

    Pérez-Calpena, A.; García-Vargas, María. Luisa; Arrillaga, X.; Gil de Paz, A.; Sánchez-Blanco, E.; Martínez-Delgado, I.; Carrera, M. A.; Gallego, J.; Carrasco, E.; Sánchez-Moreno, F. M.; Iglesias-Páramo, J.

    2014-07-01

    MEGARA (Multi Espectrógrafo en GTC de Alta Resolución para Astronomía) is the future optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) for the 10.4-m Gran Telescopio CANARIAS (GTC). MEGARA has three different fiber bundles, the Large Central Bundle covering 12.5 arcsec x 11.3 arcsec on sky, the Small Compact Bundle, of 8.5 arcsec x 6.7 arcsec, and a Fiber MOS positioner system that is able to place up to 100 mini-bundles with 7 fibers each in MOS configuration within a 3.5 arcmin x 3.5 arcmin FOV. The MEGARA focal plane subsystems are located at one of the GTC Folded Cassegrain focal stations. A field lens provides a telecentric focal plane, where the fibers are located. Micro-lenses arrays couple the telescope beam to the collimator focal ratio at the entrance of the fibers. Finally, the fibers, organized in bundles conducted the light from the focal plane to the pseudo-slit plates at the entrance of the MEGARA spectrograph, which shall be located at one of the Nasmyth platforms. This article also summarizes the prototypes already done and describes the set-up that shall be used to integrate fibers and micro-lens and characterize the fiber bundles.

  12. Bundle Binding in Polyelectrolyte Solutions

    SciTech Connect

    Stevens, M.J.

    1999-01-21

    Stiff polyelectrolytes are found to spontaneously form oriented bundles. Conditions under which bundling occurs are found. Molecular dynamics simulations show that divalent counterions are necessary, and the chains must be sufficiently long and stiff. No aggregation occurs for monovalent counterions. For flexible or short chains aggregation occurs, but bundle formation does not. Due to dynamical constraints the systems tend to order into a network of connected bundles, not a single bundle.

  13. Heterotic String Compactification and New Vector Bundles

    NASA Astrophysics Data System (ADS)

    Lin, Hai; Wu, Baosen; Yau, Shing-Tung

    2016-07-01

    We propose a construction of Kähler and non-Kähler Calabi-Yau manifolds by branched double covers of twistor spaces. In this construction we use the twistor spaces of four-manifolds with self-dual conformal structures, with the examples of connected sum of n {mathbb{P}2}s. We also construct K3-fibered Calabi-Yau manifolds from the branched double covers of the blow-ups of the twistor spaces. These manifolds can be used in heterotic string compactifications to four dimensions. We also construct stable and polystable vector bundles. Some classes of these vector bundles can give rise to supersymmetric grand unified models with three generations of quarks and leptons in four dimensions.

  14. Heterotic String Compactification and New Vector Bundles

    NASA Astrophysics Data System (ADS)

    Lin, Hai; Wu, Baosen; Yau, Shing-Tung

    2016-06-01

    We propose a construction of Kähler and non-Kähler Calabi-Yau manifolds by branched double covers of twistor spaces. In this construction we use the twistor spaces of four-manifolds with self-dual conformal structures, with the examples of connected sum of n {P2} s. We also construct K3-fibered Calabi-Yau manifolds from the branched double covers of the blow-ups of the twistor spaces. These manifolds can be used in heterotic string compactifications to four dimensions. We also construct stable and polystable vector bundles. Some classes of these vector bundles can give rise to supersymmetric grand unified models with three generations of quarks and leptons in four dimensions.

  15. Dynamics of flagellar bundling

    NASA Astrophysics Data System (ADS)

    Janssen, Pieter; Graham, Michael

    2010-11-01

    Flagella are long thin appendages of microscopic organisms used for propulsion in low-Reynolds environments. For E. coli the flagella are driven by a molecular motor, which rotates the flagella in a counter-clockwise motion (CCM). When in a forward swimming motion, all flagella bundle up. If a motor reverses rotation direction, the flagella unbundle and the cell makes a tumbling motion. When all motors turn in the same CC direction again, the flagella bundle up, and forward swimming continues. To investigate the bundling, we consider two flexible helices next to each other, as well as several flagella attached to a spherical body. Each helix is modeled as several prolate spheroids connected at the tips by springs. For hydrodynamic interactions, we consider the flagella to made up of point forces, while the finite size of the body is incorporated via Fax'en's laws. We show that synchronization occurs quickly relative to the bundling process. For flagella next to each other, the initial deflection is generated by rotlet interactions generated by the rotating helices. At longer times, simulations show the flagella only wrap once around each other, but only for flagella that are closer than about 4 helix radii. Finally, we show a run-and-tumble motion of the body with attached flagella.

  16. Linear duals of graded bundles and higher analogues of (Lie) algebroids

    NASA Astrophysics Data System (ADS)

    Bruce, Andrew James; Grabowska, Katarzyna; Grabowski, Janusz

    2016-03-01

    Graded bundles are a class of graded manifolds which represent a natural generalisation of vector bundles and include the higher order tangent bundles as canonical examples. We present and study the concept of the linearisation of graded bundle which allows us to define the notion of the linear dual of a graded bundle. They are examples of double structures, graded-linear (GL) bundles, including double vector bundles as a particular case. On GL-bundles we define what we shall call weighted algebroids, which are to be understood as algebroids in the category of graded bundles. They can be considered as a geometrical framework for higher order Lagrangian mechanics. Canonical examples are reductions of higher tangent bundles of Lie groupoids. Weighted algebroids represent also a generalisation of VB-algebroids as defined by Gracia-Saz & Mehta and the LA-bundles of Mackenzie. The resulting structures are strikingly similar to Voronov's higher Lie algebroids, however our approach does not require the initial structures to be defined on supermanifolds.

  17. Bundled monocapillary optics

    DOEpatents

    Hirsch, Gregory

    2002-01-01

    A plurality of glass or metal wires are precisely etched to form the desired shape of the individual channels of the final polycapillary optic. This shape is created by carefully controlling the withdrawal speed of a group of wires from an etchant bath. The etched wires undergo a subsequent operation to create an extremely smooth surface. This surface is coated with a layer of material which is selected to maximize the reflectivity of the radiation being used. This reflective surface may be a single layer of material, or a multilayer coating for optimizing the reflectivity in a narrower wavelength interval. The collection of individual wires is assembled into a close-packed multi-wire bundle, and the wires are bonded together in a manner which preserves the close-pack configuration, irrespective of the local wire diameter. The initial wires are then removed by either a chemical etching procedure or mechanical force. In the case of chemical etching, the bundle is generally segmented by cutting a series of etching slots. Prior to removing the wire, the capillary array is typically bonded to a support substrate. The result of the process is a bundle of precisely oriented radiation-reflecting hollow channels. The capillary optic is used for efficiently collecting and redirecting the radiation from a source of radiation which could be the anode of an x-ray tube, a plasma source, the fluorescent radiation from an electron microprobe, a synchrotron radiation source, a reactor or spallation source of neutrons, or some other source.

  18. Bioengineered anterior cruciate ligament

    NASA Technical Reports Server (NTRS)

    Altman, Gregory (Inventor); Kaplan, David (Inventor); Vunjak-Novakovic, Gordana (Inventor); Martin, Ivan (Inventor)

    2001-01-01

    The present invention provides a method for producing an anterior cruciate ligament ex vivo. The method comprises seeding pluripotent stem cells in a three dimensional matrix, anchoring the seeded matrix by attachment to two anchors, and culturing the cells within the matrix under conditions appropriate for cell growth and regeneration, while subjecting the matrix to one or more mechanical forces via movement of one or both of the attached anchors. Bone marrow stromal cells are preferably used as the pluripotent cells in the method. Suitable matrix materials are materials to which cells can adhere, such as a gel made from collagen type I. Suitable anchor materials are materials to which the matrix can attach, such as Goinopra coral and also demineralized bone. Optimally, the mechanical forces to which the matrix is subjected mimic mechanical stimuli experienced by an anterior cruciate ligament in vivo. This is accomplished by delivering the appropriate combination of tension, compression, torsion, and shear, to the matrix. The bioengineered ligament which is produced by this method is characterized by a cellular orientation and/or matrix crimp pattern in the direction of the applied mechanical forces, and also by the production of collagen type I, collagen type III, and fibronectin proteins along the axis of mechanical load produced by the mechanical forces. Optimally, the ligament produced has fiber bundles which are arranged into a helical organization. The method for producing an anterior cruciate ligament can be adapted to produce a wide range of tissue types ex vivo by adapting the anchor size and attachment sites to reflect the size of the specific type of tissue to be produced, and also adapting the specific combination of forces applied, to mimic the mechanical stimuli experienced in vivo by the specific type of tissue to be produced. The methods of the present invention can be further modified to incorporate other stimuli experienced in vivo by the

  19. Anterolateral Ligament of the Knee: Back to the Future in Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Bonasia, Davide Edoardo; D’Amelio, Andrea; Pellegrino, Pietro; Rosso, Federica; Rossi, Roberto

    2015-01-01

    Although the importance of the anterolateral stabilizing structures of the knee in the setting of anterior cruciate ligament (ACL) injuries has been recognized since many years, most of orthopedic surgeons do not take into consideration the anterolateral structures when performing an ACL reconstruction. Anatomic single or double bundle ACL reconstruction will improve knee stability, but a small subset of patients may experience some residual anteroposterior and rotational instability. For this reason, some researchers have turned again towards the anterolateral aspect of the knee and specifically the anterolateral ligament. The goal of this review is to summarize the existing knowledge regarding the anterolateral ligament of the knee, including anatomy, histology, biomechanics and imaging. In addition, the most common anterolateral reconstruction/tenodesis techniques are described together with their respective clinical outcomes. PMID:26330991

  20. Monad constructions of omalous bundles

    NASA Astrophysics Data System (ADS)

    Henni, Abdelmoubine Amar; Jardim, Marcos

    2013-12-01

    We consider a particular class of holomorphic vector bundles relevant for supersymmetric string theory, called omalous, over nonsingular projective varieties. We use monads to construct examples of such bundles over 3-fold hypersurfaces in P4, complete intersection Calabi-Yau manifolds in Pk, blow-ups of P2 at n distinct points, and products Pm×Pn.

  1. Bundle Security Protocol for ION

    NASA Technical Reports Server (NTRS)

    Burleigh, Scott C.; Birrane, Edward J.; Krupiarz, Christopher

    2011-01-01

    This software implements bundle authentication, conforming to the Delay-Tolerant Networking (DTN) Internet Draft on Bundle Security Protocol (BSP), for the Interplanetary Overlay Network (ION) implementation of DTN. This is the only implementation of BSP that is integrated with ION.

  2. ORNL rod-bundle heat-transfer test data. Volume 6. Thermal-hydraulic test facility experimental data report for test 3. 05. 5B - double-ended cold-leg break simulation

    SciTech Connect

    Mullins, C.B.; Felde, D.K.; Sutton, A.G.; Gould, S.S.; Morris, D.G.; Robinson, J.J.; Schwinkendorf, K.N.

    1982-05-18

    Thermal-Hydraulic Test Facility (THTF) Test 3.05.5B was conducted by members of the ORNL PWR Blowdown Heat Transfer Separate-Effects Program on July 3, 1980. The objective of the program is to investigate heat transfer phenomena believed to occur in PWRs during accidents, including small and large break loss-of-coolant accidents. Test 3.05.5B was designed to provide transient thermal-hydraulics data in rod bundle geometry under reactor accident-type conditions. Reduced instrument responses are presented. Also included are uncertainties in the instrument responses, calculated mass flows, and calculated rod powers.

  3. Fiber bundle phase conjugate mirror

    SciTech Connect

    Ward, Benjamin G.

    2012-05-01

    An improved method and apparatus for passively conjugating the phases of a distorted wavefronts resulting from optical phase mismatch between elements of a fiber laser array are disclosed. A method for passively conjugating a distorted wavefront comprises the steps of: multiplexing a plurality of probe fibers and a bundle pump fiber in a fiber bundle array; passing the multiplexed output from the fiber bundle array through a collimating lens and into one portion of a non-linear medium; passing the output from a pump collection fiber through a focusing lens and into another portion of the non-linear medium so that the output from the pump collection fiber mixes with the multiplexed output from the fiber bundle; adjusting one or more degrees of freedom of one or more of the fiber bundle array, the collimating lens, the focusing lens, the non-linear medium, or the pump collection fiber to produce a standing wave in the non-linear medium.

  4. Cable Bundle Wire Derating

    NASA Technical Reports Server (NTRS)

    Lundquist, Ray A.; Leidecker, Henning

    1998-01-01

    The allowable operating currents of electrical wiring when used in the space vacuum environment is predominantly determined by the maximum operating temperature of the wire insulation. For Kapton insulated wire this value is 200 C. Guidelines provided in the Goddard Space Flight Center (GSFC) Preferred Parts List (PPL) limit the operating current of wire within vacuum to ensure the maximum insulation temperature is not exceeded. For 20 AWG wire, these operating parameters are: (1) 3.7 amps per wire; (2) bundle of 15 or more wires; (3) 70 C environment: and (4) vacuum of 10(exp -5) torr or less. To determine the behavior and temperature of electrical wire at different operating conditions, a thermal vacuum test was performed on a representative electrical harness of the Hubble Space Telescope (HST) power distribution system. This paper describes the test and the results.

  5. Cable Bundle Wire Derating

    NASA Technical Reports Server (NTRS)

    Lundquist, Ray A.; Leidecker, Henning

    1999-01-01

    The allowable operating currents of electrical wiring when used in the space vacuum environment is predominantly determined by the maximum operating temperature of the wire insulation. For Kapton insulated wire this value is 200 degree C. Guidelines provided in the Goddard Space Flight Center (GSFC) Preferred Parts List (PPL) limit the operating current of wire within vacuum to ensure the maximum insulation temperature is not exceeded. For 20 AWG wire, these operating parameters are: (1) 3.7 amps per wire (2) bundle of 15 or more wires (3) 70 C environment (4) vacuum of 10(exp -5) torr or less To determine the behavior and temperature of electrical wire at different operating conditions, a thermal vacuum test was performed on a representative electrical harness of the Hubble Space Telescope (HST) power distribution system. This paper describes the test and the results.

  6. Cable Bundle Wire Derating

    NASA Technical Reports Server (NTRS)

    Lundquist, Ray A.; Leidecker, Henning

    1998-01-01

    The allowable operating currents of electrical wiring when used in the space vacuum environment is predominantly determined by the maximum operating temperature of the wire insulation. For Kapton insulated wire this value is 200 C. Guidelines provided in the Goddard Space Flight Center (GSFC) Preferred Parts List (PPL) limit the operating current of wire within vacuum to ensure the maximum insulation temperature is not exceeded. For 20 AWG wire, these operating parameters are: 3.7 amps per wire, bundle of 15 or more wires, 70 C environment, and vacuum of 10(exp -5) torr or less. To determine the behavior and temperature of electrical wire at different operating conditions, a thermal vacuum test was performed on a representative electrical harness of the Hubble Space Telescope (HST) power distribution system. This paper describes the test and the results.

  7. Design and rationale of a multicentre, randomised, double-blind, placebo-controlled clinical trial to evaluate the effect of vitamin D on ventricular remodelling in patients with anterior myocardial infarction: the VITamin D in Acute Myocardial Infarction (VITDAMI) trial

    PubMed Central

    Tuñón, José; González-Hernández, Ignacio; Llanos-Jiménez, Lucía; Alonso-Martín, Joaquín; Escudier-Villa, Juan M; Tarín, Nieves; Cristóbal, Carmen; Sanz, Petra; Pello, Ana M; Aceña, Álvaro; Carda, Rocío; Orejas, Miguel; Tomás, Marta; Beltrán, Paula; Calero Rueda, Marta; Marcos, Esther; Serrano-Antolín, José María; Gutiérrez-Landaluce, Carlos; Jiménez, Rosa; Cabezudo, Jorge; Curcio, Alejandro; Peces-Barba, Germán; González-Parra, Emilio; Muñoz-Siscart, Raquel; González-Casaus, María Luisa; Lorenzo, Antonio; Huelmos, Ana; Goicolea, Javier; Ibáñez, Borja; Hernández, Gonzalo; Alonso-Pulpón, Luis M; Farré, Jerónimo; Lorenzo, Óscar; Mahíllo-Fernández, Ignacio; Egido, Jesús

    2016-01-01

    Introduction Decreased plasma vitamin D (VD) levels are linked to cardiovascular damage. However, clinical trials have not demonstrated a benefit of VD supplements on left ventricular (LV) remodelling. Anterior ST-elevation acute myocardial infarction (STEMI) is the best human model to study the effect of treatments on LV remodelling. We present a proof-of-concept study that aims to investigate whether VD improves LV remodelling in patients with anterior STEMI. Methods and analysis The VITamin D in Acute Myocardial Infarction (VITDAMI) trial is a multicentre, randomised, double-blind, placebo-controlled trial. 144 patients with anterior STEMI will be assigned to receive calcifediol 0.266 mg capsules (Hidroferol SGC)/15 days or placebo on a 2:1 basis during 12 months. Primary objective: to evaluate the effect of calcifediol on LV remodelling defined as an increase in LV end-diastolic volume ≥10% (MRI). Secondary objectives: change in LV end-diastolic and end-systolic volumes, ejection fraction, LV mass, diastolic function, sphericity index and size of fibrotic area; endothelial function; plasma levels of aminoterminal fragment of B-type natriuretic peptide, galectin-3 and monocyte chemoattractant protein-1; levels of calcidiol (VD metabolite) and other components of mineral metabolism (fibroblast growth factor-23 (FGF-23), the soluble form of its receptor klotho, parathormone and phosphate). Differences in the effect of VD will be investigated according to the plasma levels of FGF-23 and klotho. Treatment safety and tolerability will be assessed. This is the first study to evaluate the effect of VD on cardiac remodelling in patients with STEMI. Ethics and dissemination This trial has been approved by the corresponding Institutional Review Board (IRB) and National Competent Authority (Agencia Española de Medicamentos y Productos Sanitarios (AEMPS)). It will be conducted in accordance with good clinical practice (International Council for Harmonisation of

  8. Evaluating big deal journal bundles.

    PubMed

    Bergstrom, Theodore C; Courant, Paul N; McAfee, R Preston; Williams, Michael A

    2014-07-01

    Large commercial publishers sell bundled online subscriptions to their entire list of academic journals at prices significantly lower than the sum of their á la carte prices. Bundle prices differ drastically between institutions, but they are not publicly posted. The data that we have collected enable us to compare the bundle prices charged by commercial publishers with those of nonprofit societies and to examine the types of price discrimination practiced by commercial and nonprofit journal publishers. This information is of interest to economists who study monopolist pricing, librarians interested in making efficient use of library budgets, and scholars who are interested in the availability of the work that they publish. PMID:24979785

  9. Evaluating big deal journal bundles

    PubMed Central

    Bergstrom, Theodore C.; Courant, Paul N.; McAfee, R. Preston; Williams, Michael A.

    2014-01-01

    Large commercial publishers sell bundled online subscriptions to their entire list of academic journals at prices significantly lower than the sum of their á la carte prices. Bundle prices differ drastically between institutions, but they are not publicly posted. The data that we have collected enable us to compare the bundle prices charged by commercial publishers with those of nonprofit societies and to examine the types of price discrimination practiced by commercial and nonprofit journal publishers. This information is of interest to economists who study monopolist pricing, librarians interested in making efficient use of library budgets, and scholars who are interested in the availability of the work that they publish. PMID:24979785

  10. Tube bundle system

    PubMed Central

    Marchewka, W.; Mohamed, K.; Addis, J.; Karnack, F.

    2015-01-01

    A tube bundle system (TBS) is a mechanical system for continuously drawing gas samples through tubes from multiple monitoring points located in an underground coal mine. The gas samples are drawn via vacuum pump to the surface and are typically analyzed for oxygen, methane, carbon dioxide and carbon monoxide. Results of the gas analyses are displayed and recorded for further analysis. Trends in the composition of the mine atmosphere, such as increasing methane or carbon monoxide concentration, can be detected early, permitting rapid intervention that prevents problems, such as a potentially explosive atmosphere behind seals, fire or spontaneous combustion. TBS is a well-developed technology and has been used in coal mines around the world for more than 50 years. Most longwall coal mines in Australia deploy a TBS, usually with 30 to 40 monitoring points as part of their atmospheric monitoring. The primary uses of a TBS are detecting spontaneous combustion and maintaining sealed areas inert. The TBS might also provide mine atmosphere gas composition data after a catastrophe occurs in an underground mine, if the sampling tubes are not damaged. TBSs are not an alternative to statutory gas and ventilation airflow monitoring by electronic sensors or people; rather, they are an option to consider in an overall mine atmosphere monitoring strategy. This paper describes the hardware, software and operation of a TBS and presents one example of typical data from a longwall coal mine PMID:26306052

  11. Reconnection of superfluid vortex bundles.

    PubMed

    Alamri, Sultan Z; Youd, Anthony J; Barenghi, Carlo F

    2008-11-21

    Using the vortex filament model and the Gross-Pitaevskii nonlinear Schroedinger equation, we show that bundles of quantized vortex lines in He II are structurally robust and can reconnect with each other maintaining their identity. We discuss vortex stretching in superfluid turbulence and show that, during the bundle reconnection process, kelvin waves of large amplitude are generated, in agreement with the finding that helicity is produced by nearly singular vortex interactions in classical Euler flows. PMID:19113421

  12. Phacoemulsification in anterior megalophthalmos.

    PubMed

    Lee, Graham A; Hann, Joshua V; Braga-Mele, Rosa

    2006-07-01

    This case outlines the phacoemulsification technique used to overcome the challenge of the hyperdeep anterior chamber, weak zonules, abnormal anterior capsule, and large capsular bag. Key steps included trypan blue staining of the anterior capsule, a large capsulorhexis, prolapse of the nucleus into the anterior chamber with phacoemulsification anterior to the capsulorhexis, and a posterior chamber-placed iris-clip intraocular lens. Successful visual rehabilitation is achievable in these anatomically challenging eyes. PMID:16857490

  13. Bundle Formation in Biomimetic Hydrogels.

    PubMed

    Jaspers, Maarten; Pape, A C H; Voets, Ilja K; Rowan, Alan E; Portale, Giuseppe; Kouwer, Paul H J

    2016-08-01

    Bundling of single polymer chains is a crucial process in the formation of biopolymer network gels that make up the extracellular matrix and the cytoskeleton. This bundled architecture leads to gels with distinctive properties, including a large-pore-size gel formation at very low concentrations and mechanical responsiveness through nonlinear mechanics, properties that are rarely observed in synthetic hydrogels. Using small-angle X-ray scattering (SAXS), we study the bundle formation and hydrogelation process of polyisocyanide gels, a synthetic material that uniquely mimics the structure and mechanics of biogels. We show how the structure of the material changes at the (thermally induced) gelation point and how factors such as concentration and polymer length determine the architecture, and with that, the mechanical properties. The correlation of the gel mechanics and the structural parameters obtained from SAXS experiments is essential in the design of future (synthetic) mimics of biopolymer networks. PMID:27409975

  14. Cohomology of line bundles: Applications

    NASA Astrophysics Data System (ADS)

    Blumenhagen, Ralph; Jurke, Benjamin; Rahn, Thorsten; Roschy, Helmut

    2012-01-01

    Massless modes of both heterotic and Type II string compactifications on compact manifolds are determined by vector bundle valued cohomology classes. Various applications of our recent algorithm for the computation of line bundle valued cohomology classes over toric varieties are presented. For the heterotic string, the prime examples are so-called monad constructions on Calabi-Yau manifolds. In the context of Type II orientifolds, one often needs to compute cohomology for line bundles on finite group action coset spaces, necessitating us to generalize our algorithm to this case. Moreover, we exemplify that the different terms in Batyrev's formula and its generalizations can be given a one-to-one cohomological interpretation. Furthermore, we derive a combinatorial closed form expression for two Hodge numbers of a codimension two Calabi-Yau fourfold.

  15. Ossicle in Anterior Cruciate Ligament: A Rare Occurrence

    PubMed Central

    Singh, Amanpreet; Gogna, Paritosh

    2014-01-01

    The occurrence of an intra-articular ossicle is not rare in the knee, with reports suggesting the existence of meniscal osscile. There are also reports describing the attachment of the posterolateral bundle of the anterior cruciate ligament (ACL) to an accessory ossicle. However, despite an extensive search of the English literature we did not find much written about an intrasubstance ossicle in the ACL. We present the case of a 13-year-old male with an intrasubstance ossicle in the anteromedial bundle of the ACL of his right knee. PMID:24822144

  16. Anterior vaginal wall repair

    MedlinePlus

    ... Cystocele Anterior vaginal wall repair (surgical treatment of urinary incontinence) - series References Lentz GM. Anatomic defects of the ... 72. Read More Anterior Inflatable artificial sphincter Stress urinary incontinence Urinary catheters Urinary incontinence - injectable implant Urinary incontinence - ...

  17. Chirality and equilibrium biopolymer bundles.

    PubMed

    Grason, Gregory M; Bruinsma, Robijn F

    2007-08-31

    We use continuum theory to show that chirality is a key thermodynamic control parameter for the aggregation of biopolymers: chirality produces a stable disperse phase of hexagonal bundles under moderately poor solvent conditions, as has been observed in in vitro studies of F actin [O. Pelletier et al., Phys. Rev. Lett. 91, 148102 (2003)]. The large characteristic radius of these chiral bundles is not determined by a mysterious long-range molecular interaction but by in-plane shear elastic stresses generated by the interplay between a chiral torque and an unusual, but universal, nonlinear gauge term in the strain tensor of ordered chains that is imposed by rotational invariance. PMID:17931038

  18. Exploring Bundling Theory with Geometry

    ERIC Educational Resources Information Center

    Eckalbar, John C.

    2006-01-01

    The author shows how instructors might successfully introduce students in principles and intermediate microeconomic theory classes to the topic of bundling (i.e., the selling of two or more goods as a package, rather than separately). It is surprising how much students can learn using only the tools of high school geometry. To be specific, one can…

  19. PDS4 Bundle Creation Governance Using BPMN

    NASA Astrophysics Data System (ADS)

    Radulescu, C.; Levoe, S. R.; Algermissen, S. S.; Rye, E. D.; Hardman, S. H.

    2015-06-01

    The AMMOS-PDS Pipeline Service (APPS) provides a Bundle Builder tool, which governs the process of creating, and ultimately generates, PDS4 bundles incrementally, as science products are being generated.

  20. Beta-peptide bundles with fluorous cores.

    PubMed

    Molski, Matthew A; Goodman, Jessica L; Craig, Cody J; Meng, He; Kumar, Krishna; Schepartz, Alanna

    2010-03-24

    We reported recently that certain beta-peptides self-assemble spontaneously into cooperatively folded bundles whose kinetic and thermodynamic metrics mirror those of natural helix bundle proteins. The structures of four such beta-peptide bundles are known in atomic detail. These structures reveal a solvent-sequestered, hydrophobic core stabilized by a unique arrangement of leucine side chains and backbone methylene groups. Here we report that this hydrophobic core can be re-engineered to contain a fluorous subdomain while maintaining the characteristic beta-peptide bundle fold. Like alpha-helical bundles possessing fluorous cores, fluorous beta-peptide bundles are stabilized relative to hydrocarbon analogues and undergo cold denaturation. Beta-peptide bundles with fluorous cores represent the essential first step in the synthesis of orthogonal protein assemblies that can sequester selectively in an interstitial membrane environment. PMID:20196598

  1. Quantum Bundles and Their Symmetries

    NASA Astrophysics Data System (ADS)

    Balachandran, A. P.; Marmo, G.; Simoni, A.; Sparano, G.

    Wave functions in the domain of observables such as the Hamiltonian are not always smooth functions on the classical configuration space Q. Rather, they are often best regarded as functions on a G bundle EG over Q or as sections of an associated bundle. If H is a classical group which acts on Q, its quantum version HG, which acts on EG, is not always H, but an extension of H by G. A powerful and physically transparent construction of EG and HG, where G=U(1) and H1(Q, Z)=0, has been developed using the path space {P}. ({P} consists of paths on Q from a fixed point.) In this paper we show how to construct EG and HG when G is U(1) or U(1)×π1(Q) and there is no restriction on H1(Q, Z). The method is illustrated with concrete examples, such as a system of charges and monopoles. We argue also that {P} is a sort of superbundle from which a large variety of bundles can be obtained by imposing suitable equivalence relations.

  2. Pressure Drop Characteristics in Tight-Lattice Bundles for Reduced-Moderation Water Reactors

    NASA Astrophysics Data System (ADS)

    Tamai, Hidesada; Kureta, Masatoshi; Yoshida, Hiroyuki; Akimoto, Hajime

    The reduced-moderation water reactor (RMWR) consists of several distinctive structures; a triangular tight-lattice configuration and a double-flat core. In order to design the RMWR core from the point of view of thermal-hydraulics, an evaluation method on pressure drop characteristics in the rod bundles at the tight-lattice configuration is required. In this study, calculated results by the Martinelli-Nelson's and Hancox's correlations were compared with experimental results in 4×5 rod bundles and seven-rod bundles. Consequently, the friction loss in two-phase flows becomes smaller at the tight-lattice configuration with the hydraulic diameter less than about 3mm. This reason is due to the difference of the configuration between the multi-rod bundle and the circular tube and due to the effect of the small hydraulic diameter on the two-phase multiplier.

  3. Arabidopsis VILLIN2 and VILLIN3 are required for the generation of thick actin filament bundles and for directional organ growth.

    PubMed

    van der Honing, Hannie S; Kieft, Henk; Emons, Anne Mie C; Ketelaar, Tijs

    2012-03-01

    In plant cells, actin filament bundles serve as tracks for myosin-dependent organelle movement and play a role in the organization of the cytoplasm. Although virtually all plant cells contain actin filament bundles, the role of the different actin-bundling proteins remains largely unknown. In this study, we investigated the role of the actin-bundling protein villin in Arabidopsis (Arabidopsis thaliana). We used Arabidopsis T-DNA insertion lines to generate a double mutant in which VILLIN2 (VLN2) and VLN3 transcripts are truncated. Leaves, stems, siliques, and roots of vln2 vln3 double mutant plants are twisted, which is caused by local differences in cell length. Microscopy analysis of the actin cytoskeleton showed that in these double mutant plants, thin actin filament bundles are more abundant while thick actin filament bundles are virtually absent. In contrast to full-length VLN3, truncated VLN3 lacking the headpiece region does not rescue the phenotype of the vln2 vln3 double mutant. Our results show that villin is involved in the generation of thick actin filament bundles in several cell types and suggest that these bundles are involved in the regulation of coordinated cell expansion. PMID:22209875

  4. Arabidopsis VILLIN2 and VILLIN3 Are Required for the Generation of Thick Actin Filament Bundles and for Directional Organ Growth[C][W

    PubMed Central

    van der Honing, Hannie S.; Kieft, Henk; Emons, Anne Mie C.; Ketelaar, Tijs

    2012-01-01

    In plant cells, actin filament bundles serve as tracks for myosin-dependent organelle movement and play a role in the organization of the cytoplasm. Although virtually all plant cells contain actin filament bundles, the role of the different actin-bundling proteins remains largely unknown. In this study, we investigated the role of the actin-bundling protein villin in Arabidopsis (Arabidopsis thaliana). We used Arabidopsis T-DNA insertion lines to generate a double mutant in which VILLIN2 (VLN2) and VLN3 transcripts are truncated. Leaves, stems, siliques, and roots of vln2 vln3 double mutant plants are twisted, which is caused by local differences in cell length. Microscopy analysis of the actin cytoskeleton showed that in these double mutant plants, thin actin filament bundles are more abundant while thick actin filament bundles are virtually absent. In contrast to full-length VLN3, truncated VLN3 lacking the headpiece region does not rescue the phenotype of the vln2 vln3 double mutant. Our results show that villin is involved in the generation of thick actin filament bundles in several cell types and suggest that these bundles are involved in the regulation of coordinated cell expansion. PMID:22209875

  5. Parallel transport on principal bundles over stacks

    NASA Astrophysics Data System (ADS)

    Collier, Brian; Lerman, Eugene; Wolbert, Seth

    2016-09-01

    In this paper we introduce a notion of parallel transport for principal bundles with connections over differentiable stacks. We show that principal bundles with connections over stacks can be recovered from their parallel transport thereby extending the results of Barrett, Caetano and Picken, and Schreiber and Waldorf from manifolds to stacks. In the process of proving our main result we simplify Schreiber and Waldorf's original definition of a transport functor for principal bundles with connections over manifolds and provide a more direct proof of the correspondence between principal bundles with connections and transport functors.

  6. Cotangent bundle reduction and Poincaré-Birkhoff normal forms

    NASA Astrophysics Data System (ADS)

    Çiftçi, Ünver; Waalkens, Holger; Broer, Henk W.

    2014-02-01

    In this paper we study a systematic and natural construction of canonical coordinates for the reduced space of a cotangent bundle with a free Lie group action. The canonical coordinates enable us to compute Poincaré-Birkhoff normal forms of relative equilibria using standard algorithms. The case of simple mechanical systems with symmetries is studied in detail. As examples we compute Poincaré-Birkhoff normal forms for a Lagrangian equilateral triangle configuration of a three-body system with a Morse-type potential and the stretched-out configuration of a double spherical pendulum.

  7. [Isolated anterior cervical hypertrichosis].

    PubMed

    Monteagudo, B; Cabanillas, M; de las Heras, C; Cacharrón, J M

    2009-01-01

    Anterior cervical hypertrichosis was described by Trattner and coworkers in 1991. It consists of a of hair at the anterior cervical level just above the laryngeal prominence. To date, only 28 cases of anterior cervical hypertrichosis have been reported. Although it is normally an isolated finding, it may be associated with mental retardation, hallux valgus, retinal disorders, other hair disorders, facial dysmorphism, or sensory and motor peripheral neuropathy. We report the case of a 27-year-old woman who presented with this condition as an isolated finding. PMID:19268113

  8. Global analysis of bundle behavior in pressurized water reactor specific CORA experiments

    SciTech Connect

    Hering, W. ); Minato, Kazuo; Nagase, Fumihisa )

    1993-04-01

    At Kernforschungszentrum Karlsruhe, out-of-pile bundle experiments are performed in the CORA facility to investigate the behavior of light water reactor fuel elements during severe fuel damage accidents. To analyze the phenomena observed during the tests, such as claddin failure, oxidation, and deformation, as well as their influence on the post test bundle state, four pressurized water reactor specific tests are selected: CORA-2, CORA-3, CORA-5, and CORA-12. From each of these tests, a detailed global analysis using all the measured temperatures, pressures, and fluid compositions as well as videoscope information has been performed. To describe the post test bundle state quantitatively, axial profiles of the bundle cross-section area, the damage state of the rods, the average cladding oxidation, and the damage to the pellets are measured. The effects of CORA-specific components on the bundle melt progression and the measured axial profiles are identified and assessed. Most of the observations during the tests as well as the post test bundle state can be explained by the established common sequence of phenomena. For a better understanding of the melt progression, some physical phenomena, such as the energy release associated with the double-sided oxidation of the cladding, the melt release, or the melt relocation, must be analyzed in detail.

  9. Damping Properties of the Hair Bundle

    NASA Astrophysics Data System (ADS)

    Baumgart, Johannes; Kozlov, Andrei S.; Risler, Thomas; Hudspeth, A. J.

    2011-11-01

    The viscous liquid surrounding a hair bundle dissipates energy and dampens oscillations, which poses a fundamental physical challenge to the high sensitivity and sharp frequency selectivity of hearing. To identify the mechanical forces at play, we constructed a detailed finite-element model of the hair bundle. Based on data from the hair bundle of the bullfrog's sacculus, this model treats the interaction of stereocilia both with the surrounding liquid and with the liquid in the narrow gaps between the individual stereocilia. The investigation revealed that grouping stereocilia in a bundle dramatically reduces the total drag. During hair-bundle deflections, the tip links potentially induce drag by causing small but very dissipative relative motions between stereocilia; this effect is offset by the horizontal top connectors that restrain such relative movements at low frequencies. For higher frequencies the coupling liquid is sufficient to assure that the hair bundle moves as a unit with a low total drag. This work reveals the mechanical characteristics originating from hair-bundle morphology and shows quantitatively how a hair bundle is adapted for sensitive mechanotransduction.

  10. Fock modules and noncommutative line bundles

    NASA Astrophysics Data System (ADS)

    Landi, Giovanni

    2016-09-01

    To a line bundle over a noncommutative space there is naturally associated a Fock module. The algebra of corresponding creation and annihilation operators is the total space algebra of a principal U(1) -bundle over the noncommutative space. We describe the general construction and illustrate it with examples.

  11. Net order optimization in analog net bundles

    NASA Astrophysics Data System (ADS)

    Jambor, Thomas; Schreiner, Lars; Olbrich, Markus; Barke, Erich

    2005-06-01

    This paper presents a new approach to optimize net order in analog busses. It is used for the PARasitic SYmmetric router (PARSY), which routes net bundles, e.g. busses or differential pairs, maintaining parasitic symmetry and limiting differential coupling. The router is mainly devoted to analog signal interconnect but can also be used for critical digital busses. Net bundles have a fixed order, because wire crossing is not allowed in net bundle segments to enforce symmetry. Wires inside net bundle segments are generated by module generators. Connecting cell terminals to the first or the last net bundle segment is complex, because the cell terminals can vary in geometry and placement. Therefore, an assignment between nets and wires (net order) in a segment is required. This assignment does not affect the order in which nets or net bundles are routed sequentially. The optimization objective for the connections from net bundle segments to terminals is to minimize the number of crossings and the length difference, while maintaining symmetry if possible. Therefore, a net order has to be calculated, which globally optimizes these criteria for all terminal connections. Different net orders can be computed from the placement of terminals, which have to be connected to a net bundle segment. An additional order is calculated from these net orders, which contains the most characteristic features of all net orders. For all net orders costs are evaluated, and the one with the lowest cost is chosen.

  12. Delay Tolerant Networking - Bundle Protocol Simulation

    NASA Technical Reports Server (NTRS)

    SeGui, John; Jenning, Esther

    2006-01-01

    In this paper, we report on the addition of MACHETE models needed to support DTN, namely: the Bundle Protocol (BP) model. To illustrate the useof MACHETE with the additional DTN model, we provide an example simulation to benchmark its performance. We demonstrate the use of the DTN protocol and discuss statistics gathered concerning the total time needed to simulate numerous bundle transmissions.

  13. Line bundle embeddings for heterotic theories

    NASA Astrophysics Data System (ADS)

    Nibbelin, Stefan Groot; Ruehle, Fabian

    2016-04-01

    In heterotic string theories consistency requires the introduction of a non-trivial vector bundle. This bundle breaks the original ten-dimensional gauge groups E8 × E8 or SO(32) for the supersymmetric heterotic string theories and SO(16) × SO(16) for the non-supersymmetric tachyon-free theory to smaller subgroups. A vast number of MSSM-like models have been constructed up to now, most of which describe the vector bundle as a sum of line bundles. However, there are several different ways of describing these line bundles and their embedding in the ten-dimensional gauge group. We recall and extend these different descriptions and explain how they can be translated into each other.

  14. Review of evolution of tunnel position in anterior cruciate ligament reconstruction

    PubMed Central

    Rayan, Faizal; Nanjayan, Shashi Kumar; Quah, Conal; Ramoutar, Darryl; Konan, Sujith; Haddad, Fares S

    2015-01-01

    Anterior cruciate ligament (ACL) rupture is one of the commonest knee sport injuries. The annual incidence of the ACL injury is between 100000-200000 in the United States. Worldwide around 400000 ACL reconstructions are performed in a year. The goal of ACL reconstruction is to restore the normal knee anatomy and kinesiology. The tibial and femoral tunnel placements are of primordial importance in achieving this outcome. Other factors that influence successful reconstruction are types of grafts, surgical techniques and rehabilitation programmes. A comprehensive understanding of ACL anatomy has led to the development of newer techniques supplemented by more robust biological and mechanical concepts. In this review we are mainly focussing on the evolution of tunnel placement in ACL reconstruction, focusing on three main categories, i.e., anatomical, biological and clinical outcomes. The importance of tunnel placement in the success of ACL reconstruction is well researched. Definite clinical and functional data is lacking to establish the superiority of the single or double bundle reconstruction technique. While there is a trend towards the use of anteromedial portals for femoral tunnel placement, their clinical superiority over trans-tibial tunnels is yet to be established. PMID:25793165

  15. Preliminary report: NIF laser bundle review

    SciTech Connect

    Tietbohl, G.L.; Larson, D.W.; Erlandson, A.C.

    1995-08-31

    As requested in the guidance memo {sup 1}, this committe determined whether there are compelling reasons to recommend a change from the NIF CDR baseline laser. The baseline bundle design based on a tradeoff between cost and technical risk, which is replicated four times to create the required 192 beams. The baseline amplifier design uses bottom loading 1{times}4 slab and flashlamp cassettes for amplifier maintenance and large vacuum enclosures (2.5m high {times} 7m wide in cross-section for each of the two spatial filters in each of the four bundles. The laser beams are arranged in two laser bays configured in a u-shape around the target area. The entire bundle review effort was performed in a very short time (six weeks) and with limited resources (15 personnel part-time). This should be compared to the effort that produced the CDR design (12 months, 50 to 100 personnel). This committee considered three alternate bundle configurations (2{times}2, 4{times}2, and 4{times}4 bundles), and evaluated each bundle against the baseline design using the seven requested issues in the guidance memo: Cost; schedule; performance risk; maintainability/operability; hardware failure cost exposure; activation; and design flexibility. The issues were reviewed to identify differences between each alternate bundle configuration and the baseline.

  16. Prioritary omalous bundles on Hirzebruch surfaces

    NASA Astrophysics Data System (ADS)

    Aprodu, Marian; Marchitan, Marius

    2016-01-01

    An irreducible algebraic stack is called unirational if there exists a surjective morphism, representable by algebraic spaces, from a rational variety to an open substack. We prove unirationality of the stack of prioritary omalous bundles on Hirzebruch surfaces, which implies also the unirationality of the moduli space of omalous H-stable bundles for any ample line bundle H on a Hirzebruch surface (compare with Costa and Miro-Ŕoig, 2002). To this end, we find an explicit description of the duals of omalous rank-two bundles with a vanishing condition in terms of monads. Since these bundles are prioritary, we conclude that the stack of prioritary omalous bundles on a Hirzebruch surface different from P1 ×P1 is dominated by an irreducible section of a Segre variety, and this linear section is rational (Ionescu, 2015). In the case of the space quadric, the stack has been explicitly described by N. Buchdahl. As a main tool we use Buchdahl's Beilinson-type spectral sequence. Monad descriptions of omalous bundles on hypersurfaces in P4, Calabi-Yau complete intersection, blowups of the projective plane and Segre varieties have been recently obtained by A.A. Henni and M. Jardim (Henni and Jardim, 2013), and monads on Hirzebruch surfaces have been applied in a different context in Bartocci et al. (2015).

  17. Both the middle temporal gyrus and the ventral anterior temporal area are crucial for multimodal semantic processing: distortion-corrected fMRI evidence for a double gradient of information convergence in the temporal lobes.

    PubMed

    Visser, Maya; Jefferies, Elizabeth; Embleton, Karl V; Lambon Ralph, Matthew A

    2012-08-01

    Most contemporary theories of semantic memory assume that concepts are formed from the distillation of information arising in distinct sensory and verbal modalities. The neural basis of this distillation or convergence of information was the focus of this study. Specifically, we explored two commonly posed hypotheses: (a) that the human middle temporal gyrus (MTG) provides a crucial semantic interface given the fact that it interposes auditory and visual processing streams and (b) that the anterior temporal region-especially its ventral surface (vATL)-provides a critical region for the multimodal integration of information. By utilizing distortion-corrected fMRI and an established semantic association assessment (commonly used in neuropsychological investigations), we compared the activation patterns observed for both the verbal and nonverbal versions of the same task. The results are consistent with the two hypotheses simultaneously: Both MTG and vATL are activated in common for word and picture semantic processing. Additional planned, ROI analyses show that this result follows from two principal axes of convergence in the temporal lobe: both lateral (toward MTG) and longitudinal (toward the anterior temporal lobe). PMID:22621260

  18. Contraction of cross-linked actomyosin bundles

    NASA Astrophysics Data System (ADS)

    Yoshinaga, Natsuhiko; Marcq, Philippe

    2012-08-01

    Cross-linked actomyosin bundles retract when severed in vivo by laser ablation, or when isolated from the cell and micromanipulated in vitro in the presence of ATP. We identify the timescale for contraction as a viscoelastic time τ, where the viscosity is due to (internal) protein friction. We obtain an estimate of the order of magnitude of the contraction time τ ≈ 10-100 s, consistent with available experimental data for circumferential microfilament bundles and stress fibers. Our results are supported by an exactly solvable, hydrodynamic model of a retracting bundle as a cylinder of isotropic, active matter, from which the order of magnitude of the active stress is estimated.

  19. Actively Contracting Bundles of Polar Filaments

    NASA Astrophysics Data System (ADS)

    Kruse, K.; Jülicher, F.

    2000-08-01

    We introduce a phenomenological model to study the properties of bundles of polar filaments which interact via active elements. The stability of the homogeneous state, the attractors of the dynamics in the unstable regime, and the tensile stress generated in the bundle are discussed. We find that the interaction of parallel filaments can induce unstable behavior and is responsible for active contraction and tension in the bundle. The interaction between antiparallel filaments leads to filament sorting. Our model could apply to simple contractile structures in cells such as stress fibers.

  20. Requirements for contractility in disordered cytoskeletal bundles

    NASA Astrophysics Data System (ADS)

    Lenz, Martin; Gardel, Margaret L.; Dinner, Aaron R.

    2012-03-01

    Actomyosin contractility is essential for biological force generation, and is well understood in highly organized structures such as striated muscle. Additionally, actomyosin bundles devoid of this organization are known to contract both in vivo and in vitro, which cannot be described by standard muscle models. To narrow down the search for possible contraction mechanisms in these systems, we investigate their microscopic symmetries. We show that contractile behavior requires non-identical motors that generate large-enough forces to probe the nonlinear elastic behavior of F-actin. This suggests a role for filament buckling in the contraction of these bundles, consistent with recent experimental results on reconstituted actomyosin bundles.

  1. Congenital anterior urethral diverticulum.

    PubMed

    Singh, Sanjeet Kumar; Ansari, Ms

    2014-09-01

    Congenital anterior urethral diverticulum (CAUD) may be found all along the anterior urethra and may present itself at any age, from infant to adult. Most children with this condition present with difficulty in initiating micturition, dribbling of urine, poor urinary stream, or urinary tract infection. A careful history will reveal that these children never had a good urinary stream since birth, and the telltale sign is a cystic swelling of the penile urethra. In this paper, we present two cases of CAUD that were managed by excision of the diverticulum with primary repair. PMID:26328174

  2. Characteristic classes associated to Q-bundles

    NASA Astrophysics Data System (ADS)

    Kotov, Alexei; Strobl, Thomas

    2015-10-01

    A Q-manifold is a graded manifold endowed with a vector field of degree 1 squaring to zero. We consider the notion of a Q-bundle, that is, a fiber bundle in the category of Q-manifolds. To each homotopy class of "gauge fields" (sections in the category of graded manifolds) and each cohomology class of a certain subcomplex of forms on the fiber we associate a cohomology class on the base. As any principal bundle yields canonically a Q-bundle, this construction generalizes Chern-Weil classes. Novel examples include cohomology classes that are locally de Rham differential of the integrands of topological sigma models obtained by the AKSZ-formalism in arbitrary dimensions. For Hamiltonian Poisson fibrations one obtains a characteristic 3-class in this manner. We also relate the framework to equivariant cohomology and Lecomte's characteristic classes of exact sequences of Lie algebras.

  3. Quantum Bundle Description of Quantum Projective Spaces

    NASA Astrophysics Data System (ADS)

    Ó Buachalla, Réamonn

    2012-12-01

    We realise Heckenberger and Kolb's canonical calculus on quantum projective ( N - 1)-space C q [ C p N-1] as the restriction of a distinguished quotient of the standard bicovariant calculus for the quantum special unitary group C q [ SU N ]. We introduce a calculus on the quantum sphere C q [ S 2 N-1] in the same way. With respect to these choices of calculi, we present C q [ C p N-1] as the base space of two different quantum principal bundles, one with total space C q [ SU N ], and the other with total space C q [ S 2 N-1]. We go on to give C q [ C p N-1] the structure of a quantum framed manifold. More specifically, we describe the module of one-forms of Heckenberger and Kolb's calculus as an associated vector bundle to the principal bundle with total space C q [ SU N ]. Finally, we construct strong connections for both bundles.

  4. Robust incoherent fiber optic bundle decoder

    NASA Technical Reports Server (NTRS)

    Roberts, Hilary E. (Inventor); DePlachett, Charles P. (Inventor); Deason, Brent E. (Inventor); Pilgrim, Robert A. (Inventor); Sanford, Harold S. (Inventor)

    2003-01-01

    Apparatus and method for calibrating an incoherent fiber optic bundle for use in transmitting visual or infrared coherent images. The apparatus includes a computer, a computer video monitor, an objective lens adjacent to the input end of the bundle, a second lens adjacent the output end of the bundle, and a CCD camera. The camera transmits video data to the monitor to produce an illuminated fiber optic image. The coordinates for the center of each fiber is found through an imaging process and the output fibers coordinates are related to the input fiber coordinates and processed in the computer to produce a mapping lookup-table (LUT) unique to the specific fiber bundle. Remapping of the LUT due to changes in the lens focus, CCD camera, or the addition of an infrared filter is accomplished by a software utility in the computer.

  5. [Toxic anterior segment syndrome].

    PubMed

    Cornut, P-L; Chiquet, C

    2011-01-01

    Toxic anterior segment syndrome (TASS) is a general term used to describe acute, sterile postoperative inflammation due to a non-infectious substance that accidentally enters the anterior segment at the time of surgery and mimics infectious endophthalmitis. TASS most commonly occurs acutely following anterior segment surgery, typically 12-72h after cataract extraction. Anterior segment inflammation is usually quite severe with hypopyon. Endothelial cell damage is common, resulting in diffuse corneal edema. No bacterium is isolated from ocular samples. The causes of TASS are numerous and difficult to isolate. Any device or substance used during the surgery or in the immediate postoperative period may be implicated. The major known causes include: preservatives in ophthalmic solutions, denatured ophthalmic viscosurgical devices, bacterial endotoxin, and intraocular lens-induced inflammation. Clinical features of infectious and non-infectious inflammation are initially indistinguishable and TASS is usually diagnosed and treated as acute endophthalmitis. It usually improves with local steroid treatment but may result in chronic elevation of intraocular pressure or irreversible corneal edema due to permanent damage of trabecular meshwork or endothelial cells. PMID:21176994

  6. Sealed fiber-optic bundle feedthrough

    DOEpatents

    Tanner, Carol E.

    2002-01-01

    A sealed fiber-optic bundle feedthrough by which a multitude of fiber-optic elements may be passed through an opening or port in a wall or structure separating two environments at different pressures or temperatures while maintaining the desired pressure or temperature in each environment. The feedthrough comprises a rigid sleeve of suitable material, a bundle of individual optical fibers, and a resin-based sealing material that bonds the individual optical fibers to each other and to the rigid sleeve.

  7. Unusual microtubular patterns and three-dimensional movement of mealybug sperm and sperm bundles.

    PubMed

    Ross, J; Robison, W G

    1969-02-01

    The spermatozoon of the mealybug Pseudococcus obscurus Essig is a filamentous cell (0.25 micro by 300 micro) which exhibits three-dimensional flagellations throughout most of its length. It has microtubules (200 A diameter) and a threadlike nuclear core (0.07-0.09 micro diameter) which extend almost its entire length, but apparently it has no mitochondria, centrioles, typical flagellum, or acrosome. The microtubules are arranged in two and a half concentric rings and total 56 in the most actively motile region but form two or three concentric rings with totals of 28 or 56 tubules, respectively, in less active regions. The relation of unusual microtubular patterns to the 9 + 2 complex and to flagellar motion is discussed. Mealybug spermatozoa are transmitted to the female in motile bundles which are approximately 1.3 micro by 750 micro and have four regions: (1) an anterior corkscrew region; (2) a region which contains approximately 16 spermatozoa; (3) a region of amorphous content; and (4) an endpiece. Bundle motility originates from the synchronous movements of its spermatozoa which appear to be arranged in two concentric multistranded helices. The spermatozoa provide both forward and gyratory motions of the bundle, and the corkscrew complements bundle propulsion by converting part of the rotation into forward movement. PMID:5761921

  8. Simulating Topological Defects in Twisted Fiber Bundles

    NASA Astrophysics Data System (ADS)

    Bruss, Isaac R.; Grason, Gregory M.

    2012-02-01

    Twisted bundles are a common motif found in naturally occurring structures of self-assembled fibers, such as collagen and fibrin. By understanding the general principles governing such organizations, new synthetic materials--from the nano to the macroscale--may also be realized. Recently, continuum elasticity theory has been applied to describe generic twisted fiber bundles. This has revealed a relation between a bundle's twist and the presence of topological defects in the cross-sectional packing of the fibers. Here we employ numerical simulations to examine this interdependence. We model a bundle's cross-section as beads confined to a plane. The interactions between beads is governed by a modified Lennard-Jones potential that accounts for the effects of twist. We observe configurations that range from perfect hexagonal packing for cases of no twist, to defect populated structures above a critical amount of twist. For small bundles of less than ˜100 beads, there exists a discrete spectrum of energy ground states corresponding to integer numbers of five-fold disclinations. For larger bundles, we hope to uncover what types of defect arrangements effectively screen the stresses caused by twist, and compare these to current predictions of the internal organization of collagen fibrils.

  9. The mitochondrial outer membrane is not a major diffusion barrier for ADP in mouse heart skinned fibre bundles.

    PubMed

    Kongas, Olav; Wagner, Marijke J; ter Veld, Frank; Nicolay, Klaas; van Beek, Johannes H G M; Krab, Klaas

    2004-03-01

    The response of mitochondrial oxygen consumption to ADP in saponin-skinned cardiac fibre bundles has an apparent Km an order of magnitude higher than that in isolated mitochondria. Here we report that incubating skinned cardiac fibre bundles from wild-type mice or double-knockout mice lacking both cytosolic and mitochondrial creatine kinase (CK) with CK and creatine or with yeast hexokinase and glucose as extramitochondrial ADP-producing systems decreases the apparent Km of the bundles for ADP severalfold. We conclude that the affinity of mitochondria for ADP in mouse heart is of the same order of magnitude as that of isolated mitochondria, while the high apparent Km of the bundles is caused by diffusion gradients outside the mitochondria. PMID:14722773

  10. Myosin di-phosphorylation and peripheral actin bundle formation as initial events during endothelial barrier disruption

    PubMed Central

    Hirano, Mayumi; Hirano, Katsuya

    2016-01-01

    The phosphorylation of the 20-kD myosin light chain (MLC) and actin filament formation play a key role in endothelial barrier disruption. MLC is either mono- or di-phosphorylated (pMLC and ppMLC) at T18 or S19. The present study investigated whether there are any distinct roles of pMLC and ppMLC in barrier disruption induced by thrombin. Thrombin induced a modest bi-phasic increase in pMLC and a robust mono-phasic increase in ppMLC. pMLC localized in the perinuclear cytoplasm during the initial phase, while ppMLC localized in the cell periphery, where actin bundles were formed. Later, the actin bundles were rearranged into stress fibers, where pMLC co-localized. Rho-kinase inhibitors inhibited thrombin-induced barrier disruption and peripheral localization of ppMLC and actin bundles. The double, but not single, mutation of phosphorylation sites abolished the formation of peripheral actin bundles and the barrier disruption, indicating that mono-phosphorylation of MLC at either T18 or S19 is functionally sufficient for barrier disruption. Namely, the peripheral localization, but not the degree of phosphorylation, is suggested to be essential for the functional effect of ppMLC. These results suggest that MLC phosphorylation and actin bundle formation in cell periphery are initial events during barrier disruption. PMID:26863988

  11. Buckling Behavior of Individual and Bundled Microtubules

    PubMed Central

    Soheilypour, Mohammad; Peyro, Mohaddeseh; Peter, Stephen J.; Mofrad, Mohammad R.K.

    2015-01-01

    As the major structural constituent of the cytoskeleton, microtubules (MTs) serve a variety of biological functions that range from facilitating organelle transport to maintaining the mechanical integrity of the cell. Neuronal MTs exhibit a distinct configuration, hexagonally packed bundles of MT filaments, interconnected by MT-associated protein (MAP) tau. Building on our previous work on mechanical response of axonal MT bundles under uniaxial tension, this study is focused on exploring the compression scenarios. Intracellular MTs carry a large fraction of the compressive loads sensed by the cell and therefore, like any other column-like structure, are prone to substantial bending and buckling. Various biological activities, e.g., actomyosin contractility and many pathological conditions are driven or followed by bending, looping, and buckling of MT filaments. The coarse-grained model previously developed in our lab has been used to study the mechanical behavior of individual and bundled in vivo MT filaments under uniaxial compression. Both configurations show tip-localized, decaying, and short-wavelength buckling. This behavior highlights the role of the surrounding cytoplasm and MAP tau on MT buckling behavior, which allows MT filaments to bear much larger compressive forces. It is observed that MAP tau interconnections improve this effect by a factor of two. The enhanced ability of MT bundles to damp buckling waves relative to individual MT filaments, may be interpreted as a self-defense mechanism because it helps axonal MTs to endure harsher environments while maintaining their function. The results indicate that MT filaments in a bundle do not buckle simultaneously implying that the applied stress is not equally shared among the MT filaments, that is a consequence of the nonuniform distribution of MAP tau proteins along the bundle length. Furthermore, from a pathological perspective, it is observed that axonal MT bundles are more vulnerable to failure in

  12. Nerve Bundles and Deep Dyspareunia in Endometriosis.

    PubMed

    Williams, Christina; Hoang, Lien; Yosef, Ali; Alotaibi, Fahad; Allaire, Catherine; Brotto, Lori; Fraser, Ian S; Bedaiwy, Mohamed A; Ng, Tony L; Lee, Anna F; Yong, Paul J

    2016-07-01

    The etiology of deep dyspareunia in endometriosis is unclear. Our objective was to determine whether nerve bundle density in the cul-de-sac/uterosacrals (zone II) is associated with deep dyspareunia in women with endometriosis. We conducted a blinded retrospective immunohistochemistry study (n = 58) at a tertiary referral center (2011-2013). Patients were stringently phenotyped into a study group and 2 control groups. The study group (tender endometriosis, n = 29) consisted of patients with deep dyspareunia, a tender zone II on examination, and an endometriosis lesion in zone II excised at surgery. Control group 1 (nontender endometriosis, n = 17) consisted of patients without deep dyspareunia, a nontender zone II on examination, and an endometriosis lesion in zone II excised at surgery. Control group 2 (tender nonendometriosis, n = 12) consisted of patients with deep dyspareunia, a tender zone II on examination, and a nonendometriosis lesion (eg, normal histology) in zone II excised at surgery. Protein gene product 9.5 (PGP9.5) immunohistochemistry was performed to identify nerve bundles (nerve fibers surrounded by perineurium) in the excised zone II lesion. PGP9.5 nerve bundle density (bundles/high powered field [HPF]) was then scored by a pathologist blinded to the group. We found a significant difference in PGP9.5 nerve bundle density between the 3 groups (analysis of variance, F2,55 = 6.39, P = .003). Mean PGP9.5 nerve bundle density was significantly higher in the study group (1.16 ± 0.56 bundles/HPF [±standard deviation]) compared to control group 1 (0.65 ± 0.36, Tukey test, P = .005) and control group 2 (0.72 ± 0.56, Tukey test, P = .044). This study provides evidence that neurogenesis in the cul-de-sac/uterosacrals may be an etiological factor for deep dyspareunia in endometriosis. PMID:26711313

  13. Mechanism of Actin Filament Bundling by Fascin

    SciTech Connect

    Jansen, Silvia; Collins, Agnieszka; Yang, Changsong; Rebowski, Grzegorz; Svitkina, Tatyana; Dominguez, Roberto

    2013-03-07

    Fascin is the main actin filament bundling protein in filopodia. Because of the important role filopodia play in cell migration, fascin is emerging as a major target for cancer drug discovery. However, an understanding of the mechanism of bundle formation by fascin is critically lacking. Fascin consists of four {beta}-trefoil domains. Here, we show that fascin contains two major actin-binding sites, coinciding with regions of high sequence conservation in {beta}-trefoil domains 1 and 3. The site in {beta}-trefoil-1 is located near the binding site of the fascin inhibitor macroketone and comprises residue Ser-39, whose phosphorylation by protein kinase C down-regulates actin bundling and formation of filopodia. The site in {beta}-trefoil-3 is related by pseudo-2-fold symmetry to that in {beta}-trefoil-1. The two sites are {approx}5 nm apart, resulting in a distance between actin filaments in the bundle of {approx}8.1 nm. Residue mutations in both sites disrupt bundle formation in vitro as assessed by co-sedimentation with actin and electron microscopy and severely impair formation of filopodia in cells as determined by rescue experiments in fascin-depleted cells. Mutations of other areas of the fascin surface also affect actin bundling and formation of filopodia albeit to a lesser extent, suggesting that, in addition to the two major actin-binding sites, fascin makes secondary contacts with other filaments in the bundle. In a high resolution crystal structure of fascin, molecules of glycerol and polyethylene glycol are bound in pockets located within the two major actin-binding sites. These molecules could guide the rational design of new anticancer fascin inhibitors.

  14. Anterior mandibular ameloblastoma

    PubMed Central

    Bhandarwar, Ajay H.; Bakhshi, Girish D.; Borisa, Ashok D.; Wagh, Amol; Kapoor, Rajat; Kori, Channabasappa G.

    2012-01-01

    Ameloblastoma is a benign odontogenic tumor. These are usually asymptomatic until a large size is attained. Ameloblastoma has tendency to spread locally and has a high recurrence rate. Majority of ameloblastomas (80%) arise from the mandible. Ameloblastoma arising from anterior mandibular region (symphysis-menti) is rare. Very few cases of midline anterior ameloblastomas are reported in the literature. They often require wide local excision. Reconstruction of mandible in these cases is challenging. We present a case of mandibular ameloblastoma arising from symphysis-menti. Patient underwent wide surgical excision of the tumor followed by immediate reconstruction using free fibular vascular flap, stabilized with titanium reconstructive plates. A brief case report ands review of literature is presented. PMID:24765429

  15. Anterior urethral stricture review

    PubMed Central

    Stein, Marshall J.

    2013-01-01

    Male anterior urethral stricture disease is a commonly encountered condition that presents to many urologists. According to a National Practice Survey of Board Certified Urologist in the United States most urologists treat on average 6-20 urethral strictures yearly. Many of those same urologists surveyed treat with repeated dilation or internal urethrotomy, despite continual recurrence of the urethral stricture. In point of fact, the urethroplasty despite its high success rate, is underutilized by many practicing urologists. Roughly half of practicing urologist do not perform urethroplasty in the United States. Clearly, the reconstructive ladder for urethral stricture management that was previously described in the literature may no longer apply in the modern era. The following article reviews the etiology, diagnosis, management and comparisons of treatment options for anterior urethral strictures. PMID:26816721

  16. Anterior perineal sinus.

    PubMed

    Oliver, G C; Rubin, R J; Salvati, E P; Eisenstat, T E; Lott, J

    1991-09-01

    Each year we treat several patients with an anterior perineal sinus tract. They do not conform to commonly encountered perineal problems such as pilonidal disease, epidermal cysts, hidradenitis, fistulous abscess, or inflammatory bowel disease. In an effort to improve understanding of the problem and its clinical significance, we reviewed our practice records for the period from 1968 through 1988. Fifty-six patients underwent surgery for an anterior perineal sinus tract. In 31 patients, the clinical and pathologic condition defied classical diagnostic categorization. We have termed these lesions "anterior perineal sinuses." Their clinical characteristics, treatment, and pathologic assessment from the body of this report. Male predominance (87 percent) and midlife presentation (average age, 44 years) characterized this group. Local symptoms were present from several weeks to several years prior to treatment. Local anesthesia (74 percent) and limited surgery (100 percent) resulted in complete healing in all patients (average, 7 weeks). A 15 percent recurrence rate was noted. The pathologic evaluation demonstrated acute and chronic dermal and subcutaneous inflammation. The etiology of this process remains uncertain. Its predominance along the median raphe suggests a congenital midline inclusion disorder. PMID:1914743

  17. [Cerebral white matter bundle measurements by magnetic resonance imaging].

    PubMed

    Yoshii, F; Duara, R

    1989-04-01

    The width of the anterior whole white matter bundle (AWM), interhemispheric (AWM-TER), and intrahemispheric (AWM-TRA) components at the level of the foramen of Monro on horizontal inversion recovery (IR) magnetic resonance (MR) scans were measured in 32 healthy males. The mean age of subjects were 54.4 +/- 18.8, ranged 25 to 83 years old. MR scans were performed using a 0.5 Tesla superconductive magnet, with inversion time of 400 msec, repetition time of 2.1 sec and echo time of 35 msec. The slice thickness was 10mm. Horizontal maximum internal skull diameter (HISD) at the same level was also measured and normalized values of AWM, AWM-TER, AWM-TRA were calculated by dividing the width of AWM, AWM-TER, AWM-TRA by the width of HISD. When absolute values of each AWM width were compared between right and left sides, there were no differences in AWM and AWM-TER. However, AWM-TRA of the right side was significantly wider than that of the left side (t = 4.28, p less than 0.001). The width of AWM was not correlated with age, but the width of AWM-TER showed a significant decline in the left (r = -0.36, p = 0.04) and non-significant trend to decline in the right side (r = -0.33, p = 0.07). The width of AWM-TRA of the left side was tended to decrease with age. Normalized values of AWM, AWM-TER, AWM-TRA showed a similar results as that of the absolute values. The measurement of the white matter bundle width provide some insights into the connectivity of the brain.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2612107

  18. Anterior clinoid mucocele presenting with orbital apex syndrome

    PubMed Central

    Wang, Anthony C.; Than, Khoi D.; Ramnath, Suresh; Pandey, Aditya S.

    2013-01-01

    Background: Pneumatized anterior clinoid process is a common anatomic variant. Mucocele formation is a known complication of clinoid drilling during certain intracranial operations; however, mucoceles of pneumatized anterior clinoid processes have been found to spontaneously occur. Case Description: A 44-year-old male presented with complaints of left-sided retro-orbital pain, double vision, and numbness over the upper face and scalp on the left side of 1-week duration. On examination, he was found to develop cranial nerve III, IV, and VI palsies with pupillary sparing, ophthalmic division cranial nerve V dysfunction, and eventually, the onset of vision loss. Conclusions: We report a case of spontaneous anterior clinoid process mucocele presenting with orbital apex syndrome. This was treated successfully with anterior clinoidectomy for decompression. PMID:23772333

  19. Photothermal imaging through coherent infrared bundles

    NASA Astrophysics Data System (ADS)

    Milstein, Yonat; Tepper, Michal; Harrington, James A.; Ben David, Moshe; Gannot, Israel

    2011-03-01

    This study aims to develop a photothermal imaging system through a coherent infrared bundle. This system will be used to determine the oxygenation level of various tissues, suspected malignant tissues in particular. The oxygenation estimation is preformed using a computerized algorithm. In order to evaluate the system, different bundle configurations were used for the determination of the optimal one. Bundle transmittance and the algorithm's estimation ability were measured, measurements were performed using agar phantoms consisting of varying ratios of Methylene Blue and ICG. A bundle consisting of 19 Teflon waveguides with a of 1.1mm was found to be the optimal configuration with an RMS of the error of 9.38%. At a second stage the system was validated on blood samples with varying oxygenation levels and there oxygenation levels were estimated. This stage had an RMS of the error of 10.16% for the oxygenation level estimation for samples with a 50% oxygenation level and higher. Once the basic system was validated successfully on agar phantoms and blood samples a portable system was designed and built in order to fit the system for portable use. The portable system consists of a white light illuminating source followed by filters transmitting certain wavelengths, a transmitting fiber, a thermal imaging bundle and a portable thermal camera. This portable system will be evaluated in order to have an adequate portable system for implementing the method out of the lab.

  20. The electrochemical properties of bundles of single-walled nanotubes

    SciTech Connect

    Zawodzinski, T.A. Jr.; Haridoss, P.; Uribe, F.A.

    1998-12-31

    This is the final report of a Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The authors studied electrochemical properties of single-walled fullerene nanotube bundles. The materials exhibited a highly anisotropic conductivity. Electrochemical cycling in solutions of alkyl ammonium salts in propylene carbonate revealed that the nanotubes are stable to at least {+-}1.5 V and have a fairly high accessible surface area. Double-layer charging currents of approximately 30 farads per gram were observed. This is on the same order of magnitude, though somewhat lower, than state-of-the-art values for ultra-capacitor materials. Electrochemical insertion of lithium was attempted. Though several features were observed in a slow cyclic voltammetric scan, these features were not reversible, indicating little reversible insertion. Several possible reasons for this behavior are discussed.

  1. Tapered fiber bundle couplers for high-power fiber amplifiers

    NASA Astrophysics Data System (ADS)

    Sliwinska, Dorota; Kaczmarek, Pawel; Abramski, Krzysztof M.

    2014-12-01

    In this work, we would like to demonstrate our results on performing (6+1)x1 tapered fiber bundle combiners using a trielectrode fiber splicing system. In our combiners we have used 9/80 μm (core/clad) diameter fibers as single-mode signal input ports. Using this fiber, instead of a conventional 9/125 μm single-mode fiber allowed us to reduce the taper ratio and therefore significantly increase the signal transmission. We have also performed power combiner which is based on the LMA fibers: input signal fiber 20/125μm and passive double clad fiber 25/300 μm at the output.

  2. Positional relationships between the masticatory muscles and their innervating nerves with special reference to the lateral pterygoid and the midmedial and discotemporal muscle bundles of temporalis

    PubMed Central

    AKITA, KEIICHI; SHIMOKAWA, TAKASHI; SATO, TATSUO

    2000-01-01

    For an accurate assessment of jaw movement, it is crucial to understand the comprehensive formation of the masticatory muscles with special reference to the relationship to the disc of the temporomandibular joint. Detailed dissection was performed on 26 head halves of 14 Japanese cadavers in order to obtain precise anatomical information of the positional relationships between the masticatory muscles and the branches of the mandibular nerve. After complete removal of the bony elements, the midmedial muscle bundle in all specimens and the discotemporal muscle bundle in 6 specimens, derivatives of the temporalis, which insert into the disc were observed. On the anterior area of the articular capsule and the disc of the temporomandibular joint, the upper head of the lateral pterygoid, the midmedial muscle bundle of temporalis and the discotemporal bundle of temporalis were attached mediolaterally, and in 3 specimens the posterosuperior margin of the zygomaticomandibularis was attached to the anterolateral area of the disc. It is suggested that these muscles and muscle bundles contribute to various mandibular movements. Although various patterns of the positional relationships between the muscles and muscle bundles and the their innervating nerves are observed in the present study, relative positional relationships of the muscles and muscle bundles and of nerves of the mandibular nerve are consistent. A possible scheme of the developmental formation of the masticatory muscles based on the findings of the positional relationships between the muscles and the nerves is presented. PMID:11005720

  3. Spindle neurons of the human anterior cingulate cortex

    NASA Technical Reports Server (NTRS)

    Nimchinsky, E. A.; Vogt, B. A.; Morrison, J. H.; Hof, P. R.; Bloom, F. E. (Principal Investigator)

    1995-01-01

    The human anterior cingulate cortex is distinguished by the presence of an unusual cell type, a large spindle neuron in layer Vb. This cell has been noted numerous times in the historical literature but has not been studied with modern neuroanatomic techniques. For instance, details regarding the neuronal class to which these cells belong and regarding their precise distribution along both ventrodorsal and anteroposterior axes of the cingulate gyrus are still lacking. In the present study, morphological features and the anatomic distribution of this cell type were studied using computer-assisted mapping and immunocytochemical techniques. Spindle neurons are restricted to the subfields of the anterior cingulate cortex (Brodmann's area 24), exhibiting a greater density in anterior portions of this area than in posterior portions, and tapering off in the transition zone between anterior and posterior cingulate cortex. Furthermore, a majority of the spindle cells at any level is located in subarea 24b on the gyral surface. Immunocytochemical analysis revealed that the neurofilament protein triple was present in a large percentage of these neurons and that they did not contain calcium-binding proteins. Injections of the carbocyanine dye DiI into the cingulum bundle revealed that these cells are projection neurons. Finally, spindle cells were consistently affected in Alzheimer's disease cases, with an overall loss of about 60%. Taken together, these observations indicate that the spindle cells of the human cingulate cortex represent a morphological subpopulation of pyramidal neurons whose restricted distribution may be associated with functionally distinct areas.

  4. A Kinetic Model of Active Extensile Bundles

    NASA Astrophysics Data System (ADS)

    Goldstein, Daniel; Chakraborty, Bulbul; Baskaran, Aparna

    Recent experiments in active filament networks reveal interesting rheological properties (Dan Chen: APS March Meeting 2015 D49.00001). This system consumes ATP to produce an extensile motion in bundles of microtubules. This extension then leads to self generated stresses and spontaneous flows. We propose a minimal model where the activity is modeled by self-extending bundles that are part of a cross linked network. This network can reorganize itself through buckling of extending filaments and merging events that alter the topology of the network. We numerically simulate this minimal kinetic model and examine the emergent rheological properties and determine how stresses are generated by the extensile activity. We will present results that focus on the effects of confinement and network connectivity of the bundles on stress fluctuations and response of an active gel.

  5. Extremal Bundles on Calabi-Yau Threefolds

    NASA Astrophysics Data System (ADS)

    Gao, Peng; He, Yang-Hui; Yau, Shing-Tung

    2015-06-01

    We study constructions of stable holomorphic vector bundles on Calabi-Yau threefolds, especially those with exact anomaly cancellation which we call extremal. By going through the known databases we find that such examples are rare in general and can be ruled out for the spectral cover construction for all elliptic threefolds. We then introduce a general Hartshorne-Serre construction and use it to find extremal bundles of general ranks and study their stability, as well as computing their Chern numbers. Based on both existing and our new constructions, we revisit the DRY conjecture for the existence of stable sheaves on Calabi-threefolds, and provide theoretical and numerical evidence for its correctness. Our construction can be easily generalized to bundles with no extremal conditions imposed.

  6. Hydrodynamic interaction of bacterial flagella - flagellar bundling

    NASA Astrophysics Data System (ADS)

    Lim, Sookkyung

    2013-11-01

    Flagellar bundling is an important aspect of locomotion in bacteria such as Escherichia coli. To study the hydrodynamic behavior of helical flagella, we present a computational model that is based on the geometry of the bacterial flagellar filament at the micrometer scale. We consider two model flagella, each of which has a rotary motor at its base with the rotation rate of the motor set at 100 Hz. Bundling occurs when both flagella are left-handed helices turning counterclockwise (when viewed from the nonmotor end of the flagellum looking back toward the motor) or when both flagella are right-handed helices turning clockwise. Helical flagella of the other combinations of handedness and rotation direction do not bundle. In this work we use the generalized immersed boundary method combined with the unconstrained Kirchhoff rod theory, which allows us to study the complicated hydrodynamics of flagellar behavior. This is a joint work with Charlie Peskin at NYU. NSF

  7. Carbon nanotube bundles under electric field perturbations

    NASA Astrophysics Data System (ADS)

    Hammes, I.; Latgé, A.

    2012-03-01

    Here we address the important role played by electric fields applied in carbon nanotube bundles in providing convenient scenarios for their use in electronic devices. We show that a gap modulation may be derived depending on the bundle configuration and the details of the applied field configuration. The system is described by a tight binding Hamiltonian and the Green function formalism is used to calculate the local density of states. Small bundles were used to validate our model on the basis of ab initio calculations. Further analysis shows that the number of tubes, geometrical configuration details and field intensities may be controlled to tune the electronic structure close to the Fermi energy, envisaging atomic-scale devices.

  8. Porous Silicon and Denim Fiber Bundle Characterization

    NASA Astrophysics Data System (ADS)

    Deuro, Randi Ellen

    My thesis research aims to characterize and exploit materials in an efficient, rapid, non-destructive manner. Part I of this document summarizes my research on porous silicon (pSi) design, fabrication, and surface modification for use as a novel chemical sensor. The optimization of fabrication process parameters (etching time, etching solution, electrode shape, and the fixing process) on pSi photoluminescence (PL) is presented. I have also investigated the effects of analyte vapors (acetonitrile, toluene, methanol, acetone) on the pSi PL and surface chemistry using luminescence and Fourier-transform infrared (FT-IR) spectroscopy and microscopy methods. The mechanism and benefits of one method of pSi surface modification and protection (ultraviolet (UV) hydrosilylation) will also be presented. Finally, high thorough-put methods of pSi sensor production are described. In Part II of this document, I introduce a novel technique for analyzing and discriminating among denim fiber bundles. An investigation into the benefits of luminescence-based multispectral imaging (LMSI) for denim fiber bundle identification has been conducted. I explore the power of nitromethane (CH 3NO2) based quenching in fiber bundle classification and identify the quenching mechanism. The luminescence spectra (450 - 850 nm) and images from the denim fiber bundles were obtained while exciting at 325 nm or 405 nm. Here, LMSI data were recorded in < 10 s and subsequently assessed by principal component analysis (PCA) and rendered red, green, blue (RGB) component histograms. The results show that LMSI data can be used to rapidly and uniquely classify all the fiber bundle types studied in this research. These non-destructive techniques eliminate extensive sample preparation and allow for rapid multispectral image collection, analysis, and assessment. The quenching data also revealed that the dye molecules within the individual fiber bundles exhibited dramatically different accessibilities to CH 3NO2.

  9. Infrared imaging with fiber optic bundles

    NASA Astrophysics Data System (ADS)

    Hilton, Albert R., Sr.; McCord, James; Thompson, W. S.; LeBlanc, Richard A.

    2003-09-01

    Efforts have resumed to improve the image quality of infrared imaging bundles formed at AMI using the ribbon stacking method. The C4 glass has been used to reduce core size, increase packing density and improve flexibility. Ribbons are formed from unclad fiber wound on a drum with pitch, ribbon count and spacing between ribbons computer controlled. A small portion of each ribbon is compressed and fused using thin, dilute Epoxy. Unfortunately, the Epoxy, serving as a clad, absorbs most all the LWIR energy making the bundles unsuited for 8-12 μm cameras. The ribbons are removed from the drum and stacked, one on top of the other observing proper orientation to form the bundle. A typical 1 meter bundle is formed from 50-70 count ribbons for a total of 2500-4900 fibers, made from 2.5-4.9 Km of C4 fiber. Typical core diameters are 60-80 μm. Active surface area ranges from 60-70%. Infrared resolution images formed using a NIR tube camera equipped with a special relay lens demonstrates the resolution limit for the bundle. Currently, the limit is about 10 lp/mm. The bundle end is imaged in the 3-5 μm Agema 210 camera using an Amtir 1 F/1 meniscus, coated 3-5 μm. Video images taken in natural light of an individual, easily recognizable at 50 feet, will be shown. Results of careful evaluation carried out at Lockheed Martin in Orlando using a high performance Raytheon Galileo camera will be presented.

  10. Partial tearing of the anterior cruciate ligament: diagnosis and treatment

    PubMed Central

    Temponi, Eduardo Frois; de Carvalho Júnior, Lúcio Honório; Sonnery-Cottet, Bertrand; Chambat, Pierre

    2015-01-01

    Partial tears of the anterior cruciate ligament (ACL) are common and represent 10–27% of the total. The main reasons for attending to cases of non-torn bundles are biomechanical, vascular and proprioceptive. Continued presence of the bundle also serves as protection during the healing process. There is controversy regarding the definition of these injuries, which is based on anatomy, clinical examination, translation measurements, imaging examinations and arthroscopy. The way in which it is treated will depend on the existing laxity and instability. Conservative treatment is optional for cases without instability, with a focus on motor rehabilitation. Surgical treatment is a challenge, since it requires correct positioning of the bone tunnels and conservation of the remnants of the torn bundle. The pivot shift test under anesthesia, the magnetic resonance findings, the previous level and type of sports activity and the arthroscopic appearance and mechanical properties of the remnants will aid the orthopedist in the decision-making process between conservative treatment, surgical treatment with strengthening of the native ACL (selective reconstruction) and classical (anatomical) reconstruction. PMID:26229890

  11. Bundling in semiflexible polymers: A theoretical overview.

    PubMed

    Benetatos, Panayotis; Jho, YongSeok

    2016-06-01

    Supramolecular assemblies of polymers are key modules to sustain the structure of cells and their function. The main elements of these assemblies are charged semiflexible polymers (polyelectrolytes) generally interacting via a long(er)-range repulsion and a short(er)-range attraction. The most common supramolecular structure formed by these polymers is the bundle. In the present paper, we critically review some recent theoretical and computational advances on the problem of bundle formation, and point a few promising directions for future work. PMID:26813628

  12. Scaling Shift in Multicracked Fiber Bundles

    NASA Astrophysics Data System (ADS)

    Manca, Fabio; Giordano, Stefano; Palla, Pier Luca; Cleri, Fabrizio

    2014-12-01

    Bundles of fibers, wires, or filaments are ubiquitous structures in both natural and artificial materials. We investigate the bundle degradation induced by an external damaging action through a theoretical model describing an assembly of parallel fibers, progressively damaged by a random population of cracks. Fibers in our model interact by means of a lateral linear coupling, thus retaining structural integrity even after substantial damage. Monte Carlo simulations of the Young's modulus degradation for increasing crack density demonstrate a remarkable scaling shift between an exponential and a power-law regime. Analytical solutions of the model confirm this behavior, and provide a thorough understanding of the underlying physics.

  13. Crosstalk analysis of carbon nanotube bundle interconnects.

    PubMed

    Zhang, Kailiang; Tian, Bo; Zhu, Xiaosong; Wang, Fang; Wei, Jun

    2012-01-01

    Carbon nanotube (CNT) has been considered as an ideal interconnect material for replacing copper for future nanoscale IC technology due to its outstanding current carrying capability, thermal conductivity, and mechanical robustness. In this paper, crosstalk problems for single-walled carbon nanotube (SWCNT) bundle interconnects are investigated; the interconnect parameters for SWCNT bundle are calculated first, and then the equivalent circuit has been developed to perform the crosstalk analysis. Based on the simulation results using SPICE simulator, the voltage of the crosstalk-induced glitch can be reduced by decreasing the line length, increasing the spacing between adjacent lines, or increasing the diameter of SWCNT. PMID:22340628

  14. Scaling shift in multicracked fiber bundles.

    PubMed

    Manca, Fabio; Giordano, Stefano; Palla, Pier Luca; Cleri, Fabrizio

    2014-12-19

    Bundles of fibers, wires, or filaments are ubiquitous structures in both natural and artificial materials. We investigate the bundle degradation induced by an external damaging action through a theoretical model describing an assembly of parallel fibers, progressively damaged by a random population of cracks. Fibers in our model interact by means of a lateral linear coupling, thus retaining structural integrity even after substantial damage. Monte Carlo simulations of the Young's modulus degradation for increasing crack density demonstrate a remarkable scaling shift between an exponential and a power-law regime. Analytical solutions of the model confirm this behavior, and provide a thorough understanding of the underlying physics. PMID:25554893

  15. German bundle shear - cold test results

    SciTech Connect

    Kunze, P.

    1986-01-01

    In the planned Federal Republic of Germany (FRG) reprocessing plant, the mechanical decladding of the fuel elements will be done with a bundle shear. This shear was designed and built with Thyssen Henschel by adapting the experiences of the Wiederaufarbeitungsanlage Karlsruhe (WAK), the FRG reprocessing pilot plant. The tests included boiling water reactor (BWR) and pressurized water reactor (PWR) dummy elements filled with porcelain as well as steel fuel rod simulators. During the test period with prototype bundle shear, some technical improvements have been found that refer both to operating conditions and to remote handling. In 1987 the acceptance tests will be run.

  16. Tibialis Anterior Tendon Transfer.

    PubMed

    Mulhern, Jennifer L; Protzman, Nicole M; Brigido, Stephen A

    2016-01-01

    Tendon transfer procedures are used commonly for the correction of soft tissue imbalances and instabilities. The complete transfer and the split transfer of the tibialis anterior tendon are well-accepted methods for the treatment of idiopathic equinovarus deformity in children and adults. Throughout the literature, complete and split transfer have been shown to yield significant improvements in ankle and foot range of motion and muscle function. At present, there is insufficient evidence to recommend one procedure over the other, although the split procedure has been advocated for consistently achieving inversion to eversion muscle balance without overcorrection. PMID:26590723

  17. RecA bundles mediate homology pairing between distant sisters during DNA break repair

    NASA Astrophysics Data System (ADS)

    Lesterlin, Christian; Ball, Graeme; Schermelleh, Lothar; Sherratt, David J.

    2014-02-01

    DNA double-strand break (DSB) repair by homologous recombination has evolved to maintain genetic integrity in all organisms. Although many reactions that occur during homologous recombination are known, it is unclear where, when and how they occur in cells. Here, by using conventional and super-resolution microscopy, we describe the progression of DSB repair in live Escherichia coli. Specifically, we investigate whether homologous recombination can occur efficiently between distant sister loci that have segregated to opposite halves of an E. coli cell. We show that a site-specific DSB in one sister can be repaired efficiently using distant sister homology. After RecBCD processing of the DSB, RecA is recruited to the cut locus, where it nucleates into a bundle that contains many more RecA molecules than can associate with the two single-stranded DNA regions that form at the DSB. Mature bundles extend along the long axis of the cell, in the space between the bulk nucleoid and the inner membrane. Bundle formation is followed by pairing, in which the two ends of the cut locus relocate at the periphery of the nucleoid and together move rapidly towards the homology of the uncut sister. After sister locus pairing, RecA bundles disassemble and proteins that act late in homologous recombination are recruited to give viable recombinants 1-2-generation-time equivalents after formation of the initial DSB. Mutated RecA proteins that do not form bundles are defective in sister pairing and in DSB-induced repair. This work reveals an unanticipated role of RecA bundles in channelling the movement of the DNA DSB ends, thereby facilitating the long-range homology search that occurs before the strand invasion and transfer reactions.

  18. RecA bundles mediate homology pairing between distant sisters during DNA break repair.

    PubMed

    Lesterlin, Christian; Ball, Graeme; Schermelleh, Lothar; Sherratt, David J

    2014-02-13

    DNA double-strand break (DSB) repair by homologous recombination has evolved to maintain genetic integrity in all organisms. Although many reactions that occur during homologous recombination are known, it is unclear where, when and how they occur in cells. Here, by using conventional and super-resolution microscopy, we describe the progression of DSB repair in live Escherichia coli. Specifically, we investigate whether homologous recombination can occur efficiently between distant sister loci that have segregated to opposite halves of an E. coli cell. We show that a site-specific DSB in one sister can be repaired efficiently using distant sister homology. After RecBCD processing of the DSB, RecA is recruited to the cut locus, where it nucleates into a bundle that contains many more RecA molecules than can associate with the two single-stranded DNA regions that form at the DSB. Mature bundles extend along the long axis of the cell, in the space between the bulk nucleoid and the inner membrane. Bundle formation is followed by pairing, in which the two ends of the cut locus relocate at the periphery of the nucleoid and together move rapidly towards the homology of the uncut sister. After sister locus pairing, RecA bundles disassemble and proteins that act late in homologous recombination are recruited to give viable recombinants 1-2-generation-time equivalents after formation of the initial DSB. Mutated RecA proteins that do not form bundles are defective in sister pairing and in DSB-induced repair. This work reveals an unanticipated role of RecA bundles in channelling the movement of the DNA DSB ends, thereby facilitating the long-range homology search that occurs before the strand invasion and transfer reactions. PMID:24362571

  19. Laser-guided placement of the tibial guide in the transtibial technique for anterior cruciate ligament reconstruction.

    PubMed

    Takahashi, Toshiaki; Takeda, Haruhiko; Watanabe, Seiji; Yamamoto, Haruyasu

    2009-02-01

    In anterior cruciate ligament (ACL) reconstruction, it is important to determine the location and direction of the femoral bone tunnel when using the transtibial technique. Accurately identifying the anatomic location at which to make the femoral bone tunnel for double-bundle ACL reconstruction is not a straightforward procedure. We describe a new method in which the centrum of the femoral tunnel is marked with an awl and a laser beam-guided technique is used to place the tibial pin. This procedure allows us to mark the desired location of the femoral tunnel before drilling the tibial bone tunnel when using the transtibial technique. This is the first report of a laser-guided technique used in arthroscopic surgery. We used a laser beam to determine the location of the femoral tunnel--the anatomic site needed to perform the intra-articular drilling in the tibia. In this technique, a laser pointer is set at the tibial guide, which reflects the laser beam and illuminates the point where the femoral bone tunnel should be made. Our method offers an easy and accurate way to reconfirm the tibial placement before drilling. PMID:19171283

  20. Uveitis (acute anterior)

    PubMed Central

    2010-01-01

    Introduction Anterior uveitis is rare, with an annual incidence of 12/100,000 population, although it is more common in Finland (annual incidence of 23/100,000), probably because of genetic factors, such as high frequency of HLA–B27 in the population. It is often self-limiting, but can, in some cases, lead to complications such as posterior synechiae, cataract, glaucoma, and chronic uveitis. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical question: What are the effects of anti-inflammatory eye drops on acute anterior uveitis? We searched: Medline, Embase, The Cochrane Library and other important databases up to November 2009 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found six systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: corticosteroids, mydriatics, and non-steroidal anti-inflammatory drug eye drops. PMID:21736765

  1. Social Bundles: Thinking through the Infant Body

    ERIC Educational Resources Information Center

    Brownlie, Julie; Leith, Valerie M. Sheach

    2011-01-01

    Drawing on a UK research study on immunization, this article investigates parents' understandings of the relationship between themselves, their infants, other bodies, the state, and cultural practices--material and symbolic. The article argues that infant bodies are best thought of as always social bundles, rather than as biobundles made social…

  2. High precision optical fiber bundle displacement sensor

    NASA Astrophysics Data System (ADS)

    Cao, Hui-min; Chen, You-ping; Zhang, Gang; Zhou, Zu-de

    2006-02-01

    A noncontact optical fiber bundle displacement sensor with nanometer resolution and low drift is proposed. The principle of the sensor is based on reflective intensity modulation technique. The optical fiber bundle probe contains one transmitting bundle and two receiving bundles. There are 727 identical glass optical fibers with a diameter of 50μm arranged in a concentric random pattern at the probe end. The diameter of the probe coated with a thin stainless ferrule is as small as 2.5mm. A carrier amplifier system is adopted to reduce dc drift and the interference of ambient stray light. The disturbance caused by fluctuation of light source and variation of target surface reflectivity is eliminated by taking a ratio of two receiving signals. The thermal drifts from two photoelectric signal processing circuits cancel out each other by using elements with identical specifications for both photodetector-amplifier chains. The sensitivity of the sensor is 5.9mV/nm over a linear range of 700-2300μm with a nonlinearity of 1%. The achieved resolution is 1nm/square root Hz; over a dynamic bandwidth of 10KHz and the dynamic range is 286dB. It has been proved that the sensor run sufficiently well when used with nano-technological instruments.

  3. The Bundled Payments for Care Improvement Initiative.

    PubMed

    Hirsch, Joshua A; Leslie-Mazwi, Thabele M; Barr, Robert M; McGinty, Geraldine; Nicola, Gregory N; Silva, Ezequiel; Manchikanti, Laxmaiah

    2016-05-01

    The Affordable Care Act enters its fifth year firmly entrenched in our national consciousness. One method that has entered the vernacular for achieving cost savings is accountable care. There are other approaches that are less well known. The Bundled Payments for Care Improvement Initiative has the potential to significantly impact neurointerventionalists. We review that initiative here. PMID:25829366

  4. Interplanetary Overlay Network Bundle Protocol Implementation

    NASA Technical Reports Server (NTRS)

    Burleigh, Scott C.

    2011-01-01

    The Interplanetary Overlay Network (ION) system's BP package, an implementation of the Delay-Tolerant Networking (DTN) Bundle Protocol (BP) and supporting services, has been specifically designed to be suitable for use on deep-space robotic vehicles. Although the ION BP implementation is unique in its use of zero-copy objects for high performance, and in its use of resource-sensitive rate control, it is fully interoperable with other implementations of the BP specification (Internet RFC 5050). The ION BP implementation is built using the same software infrastructure that underlies the implementation of the CCSDS (Consultative Committee for Space Data Systems) File Delivery Protocol (CFDP) built into the flight software of Deep Impact. It is designed to minimize resource consumption, while maximizing operational robustness. For example, no dynamic allocation of system memory is required. Like all the other ION packages, ION's BP implementation is designed to port readily between Linux and Solaris (for easy development and for ground system operations) and VxWorks (for flight systems operations). The exact same source code is exercised in both environments. Initially included in the ION BP implementations are the following: libraries of functions used in constructing bundle forwarders and convergence-layer (CL) input and output adapters; a simple prototype bundle forwarder and associated CL adapters designed to run over an IPbased local area network; administrative tools for managing a simple DTN infrastructure built from these components; a background daemon process that silently destroys bundles whose time-to-live intervals have expired; a library of functions exposed to applications, enabling them to issue and receive data encapsulated in DTN bundles; and some simple applications that can be used for system checkout and benchmarking.

  5. An Alternative Bundle-to-Bundle Suturing Technique for Repairing Fresh Achilles Tendon Rupture.

    PubMed

    Zhao, Jingjing; Yu, Bin; Xie, Ming; Huang, Ruokun; Xiao, Kai

    2016-01-01

    The main concern about conventional Achilles tendon repair surgical techniques is how to maintain the initial strength of the ruptured Achilles tendon through complicated suturing methods. The primary surgical problem lies in the properties of the soft tissue; the deterioration of the Achilles tendon, especially in its elasticity; and the surface lubricity of the local tissues. In the present study, we describe an innovative bundle-to-bundle suturing method that addresses these potential problems. PMID:26970908

  6. Anterior hip pain.

    PubMed

    O'Kane, J W

    1999-10-15

    Anterior hip pain is a common complaint with many possible causes. Apophyseal avulsion and slipped capital femoral epiphysis should not be overlooked in adolescents. Muscle and tendon strains are common in adults. Subsequent to accurate diagnosis, strains should improve with rest and directed conservative treatment. Osteoarthritis, which is diagnosed radiographically, generally occurs in middle-aged and older adults. Arthritis in younger adults should prompt consideration of an inflammatory cause. A possible femoral neck stress fracture should be evaluated urgently to prevent the potentially significant complications associated with displacement. Patients with osteitis pubis should be educated about the natural history of the condition and should undergo physical therapy to correct abnormal pelvic mechanics. "Sports hernias," nerve entrapments and labral pathologic conditions should be considered in athletic adults with characteristic presentations and chronic symptoms. Surgical intervention may allow resumption of pain-free athletic activity. PMID:10537384

  7. Sperm Bundles in the Seminal Vesicles of Sexually Mature Lasius Ant Males

    PubMed Central

    Burnett, William E.; Heinze, Jürgen

    2014-01-01

    In many insects, sperm cells are produced in bundles with their heads being held together by a glycoprotein matrix secreted by a cyst cell. Mature sperm cells in the seminal vesicles are usually free, but in sawflies and several other insects, such structures (spermatodesmata) remain intact and sperm cells may be ejaculated as bundles. Here we report the occurrence of spermatodesmata in mature males of the ant Lasius pallitarsis. Microscopic investigations of the abdominal contents of males immediately prior to their nuptial flights showed that the anterior ends of numerous sperm cells were embedded in an oval-shaped 20 by 30 micrometer extracellular fibrous cap. Individual sperm ranged in length from 55 to 75 micrometers with an average overall length of 65 micrometers. The bulb-shaped heads of the sperm were relatively small, only about 1.5 micrometers in length and about 1.1 micrometers in diameter. The diameter of the sperm tails was approximately 1 micrometer. Observations of live preparations of the spermatodesmata showed increasingly active undulating wave-like movement of the sperm tails as the slide preparations aged. This appears to be the first case of sperm bundles being present in the seminal vesicles of mature ant males – males that are immediately poised to complete their nuptial mating flight. PMID:24671307

  8. The Pronator Quadratus and Distal Anterior Interosseous Nerve: A Cadaveric Study

    PubMed Central

    Hinds, Richard M.; Gottschalk, Michael B.; Capo, John T.

    2015-01-01

    Background The pronator quadratus (PQ) muscle is an important and commonly encountered structure in surgery of the wrist. A thorough understanding of the anatomy of the PQ and the anterior interosseous nerve (AIN), which innervates the PQ, is important, particularly during distal radius fracture osteosynthesis and distal AIN transfer to deep branch of the ulnar nerve. Furthermore, there is a paucity of literature regarding sex differences in the morphology of these structures. We describe the morphology of the PQ and AIN and compare PQ and AIN findings in male and female specimens. Methods Twenty-five cadaveric upper extremities underwent loupe-aided dissection of the volar forearm with identification of the AIN and PQ. A digital photograph taken perpendicular to the volar surface of the forearm was used to measure the PQ and assess AIN morphology using ImageJ (National Institutes of Health; Bethesda, MD). Comparisons between male and female specimens were performed. Results Of the 25 specimens, 84% appeared as a single trapezoidal muscle bundle, with the remaining 16% demonstrating a double-bundle morphology. The PQ was a mean 3.8 ± 0.5 cm in radial-ulnar width and 4.6 ± 0.7 cm in proximal-distal length with a mean thickness, area, and volume of 0.6 ± 0.2 cm, 18.2 ± 4.8 cm2, and 10.5 ± 3.7 cm3, respectively. The PQ branch of the AIN was a mean 3.8 ± 1.1 cm long and had a mean diameter of 1.4 ± 0.2 mm. Male specimens demonstrated significantly greater radial-ulnar width (p = 0.005), area (p = 0.006), and volume (p = 0.033) of the PQ, as well as a greater distance from the radial styloid to the distal arborization of the AIN (p = 0.005) compared with female specimens. Conclusions The current study informs hand surgeons of the morphologic variability and sexual dimorphism of the PQ and AIN and may help guide operative planning. PMID:26261744

  9. [Anterior cervical hypertrichosis: case report].

    PubMed

    Orozco-Gutiérrez, Mario H; Sánchez-Corona, José; García-Ortiz, José E; Castañeda-Cisneros, Gema; Dávalos-Rodríguez, Nory O; Corona-Rivera, Jorge R; García-Cruz, Diana

    2016-10-01

    The non-syndromic anterior cervical hypertrichosis (OMIM N° 600457) is a genetic disorder characterized by a patch of hair at the level of the laryngeal prominence. We present a 12-year-old boy with anterior cervical hypertrichosis and mild generalized hypertrichosis. He has no neurological, ophthalmological or skeletal anomalies. The clinical follow up is 10 years. PMID:27606653

  10. Oxidation induced stress-rupture of fiber bundles

    SciTech Connect

    Lara-Curzio, E.

    1997-03-01

    The effect of oxidation on the stress-rupture behavior of fiber bundles was modeled. It is shown that oxidation-induced fiber strength degradation results in the delayed failure of the associated fiber bundle and that the fiber bundle strength decreases with time as t{sup {minus}1/4}. It is also shown that the temperature dependence of the bundle loss of strength reflects the thermal dependence of the mechanism controlling the oxidation of the fibers. The effect of gauge length on the fiber bundle strength was also analyzed. Numerical examples are presented for the special case of Nicalon{trademark} fibers.

  11. Multiwalled carbon nanotube reinforced biomimetic bundled gel fibres.

    PubMed

    Kim, Young-Jin; Yamamoto, Seiichiro; Takahashi, Haruko; Sasaki, Naruo; Matsunaga, Yukiko T

    2016-08-19

    This work describes the fabrication and characterization of hydroxypropyl cellulose (HPC)-based biomimetic bundled gel fibres. The bundled gel fibres were reinforced with multiwalled carbon nanotubes (MWCNTs). A phase-separated aqueous solution with MWCNT and HPC was transformed into a bundled fibrous structure after being injected into a co-flow microfluidic device and applying the sheath flow. The resulting MWCNT-bundled gel fibres consist of multiple parallel microfibres. The mechanical and electrical properties of MWCNT-bundled gel fibres were improved and their potential for tissue engineering applications as a cell scaffold was demonstrated. PMID:27200527

  12. Emitters of N-photon bundles.

    PubMed

    Muñoz, C Sánchez; Del Valle, E; Tudela, A González; Müller, K; Lichtmannecker, S; Kaniber, M; Tejedor, C; Finley, J J; Laussy, F P

    2014-07-01

    Controlling the ouput of a light emitter is one of the basic tasks of photonics, with landmarks such as the laser and single-photon sources. The development of quantum applications makes it increasingly important to diversify the available quantum sources. Here, we propose a cavity QED scheme to realize emitters that release their energy in groups, or "bundles" of N photons, for integer N. Close to 100% of two-photon emission and 90% of three-photon emission is shown to be within reach of state of the art samples. The emission can be tuned with system parameters so that the device behaves as a laser or as a N-photon gun. The theoretical formalism to characterize such emitters is developed, with the bundle statistics arising as an extension of the fundamental correlation functions of quantum optics. These emitters will be useful for quantum information processing and for medical applications. PMID:25013456

  13. Phase Slips in Oscillatory Hair Bundles

    PubMed Central

    Roongthumskul, Yuttana; Shlomovitz, Roie; Bruinsma, Robijn; Bozovic, Dolores

    2013-01-01

    Hair cells of the inner ear contain an active amplifier that allows them to detect extremely weak signals. As one of the manifestations of an active process, spontaneous oscillations arise in fluid immersed hair bundles of in vitro preparations of selected auditory and vestibular organs. We measure the phase-locking dynamics of oscillatory bundles exposed to low-amplitude sinusoidal signals, a transition that can be described by a saddle-node bifurcation on an invariant circle. The transition is characterized by the occurrence of phase slips, at a rate that is dependent on the amplitude and detuning of the applied drive. The resultant staircase structure in the phase of the oscillation can be described by the stochastic Adler equation, which reproduces the statistics of phase slip production. PMID:25167040

  14. Phase slips in oscillatory hair bundles.

    PubMed

    Roongthumskul, Yuttana; Shlomovitz, Roie; Bruinsma, Robijn; Bozovic, Dolores

    2013-04-01

    Hair cells of the inner ear contain an active amplifier that allows them to detect extremely weak signals. As one of the manifestations of an active process, spontaneous oscillations arise in fluid immersed hair bundles of in vitro preparations of selected auditory and vestibular organs. We measure the phase-locking dynamics of oscillatory bundles exposed to low-amplitude sinusoidal signals, a transition that can be described by a saddle-node bifurcation on an invariant circle. The transition is characterized by the occurrence of phase slips, at a rate that is dependent on the amplitude and detuning of the applied drive. The resultant staircase structure in the phase of the oscillation can be described by the stochastic Adler equation, which reproduces the statistics of phase slip production. PMID:25167040

  15. Covariance and the hierarchy of frame bundles

    NASA Technical Reports Server (NTRS)

    Estabrook, Frank B.

    1987-01-01

    This is an essay on the general concept of covariance, and its connection with the structure of the nested set of higher frame bundles over a differentiable manifold. Examples of covariant geometric objects include not only linear tensor fields, densities and forms, but affinity fields, sectors and sector forms, higher order frame fields, etc., often having nonlinear transformation rules and Lie derivatives. The intrinsic, or invariant, sets of forms that arise on frame bundles satisfy the graded Cartan-Maurer structure equations of an infinite Lie algebra. Reduction of these gives invariant structure equations for Lie pseudogroups, and for G-structures of various orders. Some new results are introduced for prolongation of structure equations, and for treatment of Riemannian geometry with higher-order moving frames. The use of invariant form equations for nonlinear field physics is implicitly advocated.

  16. Phase Slips in Oscillatory Hair Bundles

    NASA Astrophysics Data System (ADS)

    Roongthumskul, Yuttana; Shlomovitz, Roie; Bruinsma, Robijn; Bozovic, Dolores

    2013-04-01

    Hair cells of the inner ear contain an active amplifier that allows them to detect extremely weak signals. As one of the manifestations of an active process, spontaneous oscillations arise in fluid immersed hair bundles of in vitro preparations of selected auditory and vestibular organs. We measure the phase-locking dynamics of oscillatory bundles exposed to low-amplitude sinusoidal signals, a transition that can be described by a saddle-node bifurcation on an invariant circle. The transition is characterized by the occurrence of phase slips, at a rate that is dependent on the amplitude and detuning of the applied drive. The resultant staircase structure in the phase of the oscillation can be described by the stochastic Adler equation, which reproduces the statistics of phase slip production.

  17. Are Medicare bundles in your future?

    PubMed

    Mulvany, Chad

    2015-08-01

    To ensure they are well-positioned for an expansion by the Centers for Medicare & Medicaid Services of bundled payment, hospitals that are not participants in the Bundled Payments for Care Improvement initiative should take the following steps: Understand which organizations in their markets are already participating and which might participate. Understand care utilization patterns within their care delivery networks and how those patterns affect cost per episode. Identify high-quality, cost-efficient postacute care providers and begin collaborating with them to further improve outcomes. Educate discharging physicians about the impact that choices related to postacute settings have on both beneficiary out-of-pocket obligations and overall cost of care. PMID:26548136

  18. Hierarchical scaling law for the strength of composite fibre bundles

    NASA Astrophysics Data System (ADS)

    Pimenta, Soraia; Pinho, Silvestre T.

    2013-06-01

    This paper presents an analytical model for size effects on the longitudinal tensile strength of composite fibre bundles. The strength of individual fibres is modelled by a Weibull distribution, while the matrix (or fibre-matrix interface) is represented through a perfectly plastic shear-lag model. A probabilistic analysis of the failure process in hierarchical bundles (bundles of bundles) is performed, so that a scaling law relating the strength distributions and characteristic lengths of consecutive bundle levels is derived. An efficient numerical scheme (based on asymptotic limits) is proposed, hence coupon-sized bundle strength distributions are obtained almost instantaneously. Parametric studies show that both fibre and matrix properties are critical for bundle strength; model predictions at different scales are validated against experimental results available in the literature.

  19. Uncovering Ecosystem Service Bundles through Social Preferences

    PubMed Central

    Martín-López, Berta; Iniesta-Arandia, Irene; García-Llorente, Marina; Palomo, Ignacio; Casado-Arzuaga, Izaskun; Amo, David García Del; Gómez-Baggethun, Erik; Oteros-Rozas, Elisa; Palacios-Agundez, Igone; Willaarts, Bárbara; González, José A.; Santos-Martín, Fernando; Onaindia, Miren; López-Santiago, Cesar; Montes, Carlos

    2012-01-01

    Ecosystem service assessments have increasingly been used to support environmental management policies, mainly based on biophysical and economic indicators. However, few studies have coped with the social-cultural dimension of ecosystem services, despite being considered a research priority. We examined how ecosystem service bundles and trade-offs emerge from diverging social preferences toward ecosystem services delivered by various types of ecosystems in Spain. We conducted 3,379 direct face-to-face questionnaires in eight different case study sites from 2007 to 2011. Overall, 90.5% of the sampled population recognized the ecosystem’s capacity to deliver services. Formal studies, environmental behavior, and gender variables influenced the probability of people recognizing the ecosystem’s capacity to provide services. The ecosystem services most frequently perceived by people were regulating services; of those, air purification held the greatest importance. However, statistical analysis showed that socio-cultural factors and the conservation management strategy of ecosystems (i.e., National Park, Natural Park, or a non-protected area) have an effect on social preferences toward ecosystem services. Ecosystem service trade-offs and bundles were identified by analyzing social preferences through multivariate analysis (redundancy analysis and hierarchical cluster analysis). We found a clear trade-off among provisioning services (and recreational hunting) versus regulating services and almost all cultural services. We identified three ecosystem service bundles associated with the conservation management strategy and the rural-urban gradient. We conclude that socio-cultural preferences toward ecosystem services can serve as a tool to identify relevant services for people, the factors underlying these social preferences, and emerging ecosystem service bundles and trade-offs. PMID:22720006

  20. Alpha1 LASSO data bundles Lamont, OK

    DOE Data Explorer

    Gustafson, William Jr; Vogelmann, Andrew; Endo, Satoshi; Toto, Tami; Xiao, Heng; Li, Zhijin; Cheng, Xiaoping; Krishna, Bhargavi (ORCID:000000018828528X)

    2016-08-03

    A data bundle is a unified package consisting of LASSO LES input and output, observations, evaluation diagnostics, and model skill scores. LES input includes model configuration information and forcing data. LES output includes profile statistics and full domain fields of cloud and environmental variables. Model evaluation data consists of LES output and ARM observations co-registered on the same grid and sampling frequency. Model performance is quantified by skill scores and diagnostics in terms of cloud and environmental variables.

  1. Stable vector bundles and string theory

    SciTech Connect

    Gomez, Tomas L.; Sols, Ignacio; Lukic, Sergio

    2009-05-06

    In [4], Braun, He, Ovrut and Pantev proposed a model of string theory (based on the Calabi-Yau 3-fold X) whose low energy limit predicts certain properties of the Standard Model of particle Physics. This model depends on two vector bundles that have to be stable. We calculate the ample cone of X, and prove that one of them is stable, and the other one is not.

  2. Carbon Nanotube Bundle Array Cold Cathodes for THz Vacuum Tube Sources

    NASA Astrophysics Data System (ADS)

    Manohara, Harish M.; Toda, Risaku; Lin, Robert H.; Liao, Anna; Bronikowski, Michael J.; Siegel, Peter H.

    2009-12-01

    We present high performance cold cathodes composed of arrays of carbon nanotube bundles that routinely produce > 15 A/cm2 at applied fields of 5 to 8 V/µm without any beam focusing. They have exhibited robust operation in poor vacuums of 10-6 to 10-4 Torr- a typically achievable range inside hermetically sealed microcavities. A new double-SOI process was developed to monolithically integrate a gate and additional beam tailoring electrodes. The ability to design the electrodes for specific requirements makes carbon nanotube field emission sources extremely flexible. The lifetime of these cathodes is found to be affected by two effects: a gradual decay of emission due to anode sputtering, and catastrophic failure because of dislodging of CNT bundles at high fields ( > 10 V/µm).

  3. An analytical fiber bundle model for pullout mechanics of root bundles

    NASA Astrophysics Data System (ADS)

    Cohen, D.; Schwarz, M.; Or, D.

    2011-09-01

    Roots in soil contribute to the mechanical stability of slopes. Estimation of root reinforcement is challenging because roots form complex biological networks whose geometrical and mechanical characteristics are difficult to characterize. Here we describe an analytical model that builds on simple root descriptors to estimate root reinforcement. Root bundles are modeled as bundles of heterogeneous fibers pulled along their long axes neglecting root-soil friction. Analytical expressions for the pullout force as a function of displacement are derived. The maximum pullout force and corresponding critical displacement are either derived analytically or computed numerically. Key model inputs are a root diameter distribution (uniform, Weibull, or lognormal) and three empirical power law relations describing tensile strength, elastic modulus, and length of roots as functions of root diameter. When a root bundle with root tips anchored in the soil matrix is pulled by a rigid plate, a unique parameter, ?, that depends only on the exponents of the power law relations, dictates the order in which roots of different diameters break. If ? < 1, small roots break first; if ? > 1, large roots break first. When ? = 1, all fibers break simultaneously, and the maximum tensile force is simply the roots' mean force times the number of roots in the bundle. Based on measurements of root geometry and mechanical properties, the value of ? is less than 1, usually ranging between 0 and 0.7. Thus, small roots always fail first. The model shows how geometrical and mechanical characteristics of roots and root diameter distribution affect the pullout force, its maximum and corresponding displacement. Comparing bundles of roots that have similar mean diameters, a bundle with a narrow variance in root diameter will result in a larger maximum force and a smaller displacement at maximum force than a bundle with a wide diameter distribution. Increasing the mean root diameter of a bundle without

  4. Bundled payment fails to gain a foothold In California: the experience of the IHA bundled payment demonstration.

    PubMed

    Ridgely, M Susan; de Vries, David; Bozic, Kevin J; Hussey, Peter S

    2014-08-01

    To determine whether bundled payment could be an effective payment model for California, the Integrated Healthcare Association convened a group of stakeholders (health plans, hospitals, ambulatory surgery centers, physician organizations, and vendors) to develop, through a consensus process, the methods and means of implementing bundled payment. In spite of a high level of enthusiasm and effort, the pilot did not succeed in its goal to implement bundled payment for orthopedic procedures across multiple payers and hospital-physician partners. An evaluation of the pilot documented a number of barriers, such as administrative burden, state regulatory uncertainty, and disagreements about bundle definition and assumption of risk. Ultimately, few contracts were signed, which resulted in insufficient volume to test hypotheses about the impact of bundled payment on quality and costs. Although bundled payment failed to gain a foothold in California, the evaluation provides lessons for future bundled payment initiatives. PMID:25092835

  5. Anterior radical debridement and anterior instrumentation in tuberculosis spondylitis.

    PubMed

    Benli, I Teoman; Acaroğlu, Emre; Akalin, Serdar; Kiş, Mahmut; Duman, Evrim; Un, Ahmet

    2003-04-01

    The conventional procedure in the treatment of vertebral tuberculosis is drainage of the abscess, curettage of the devitalized vertebra and application of an antituberculous chemotherapy regimen. Posterior instrumentation results are encouraging in the prevention or treatment of late kyphosis; however, a second-stage operation is needed. Recently, posterolateral or transpedicular drainage without anterior drainage or posterior instrumentation following anterior drainage in the same session has become the preferred treatment, in order that kyphotic deformity can be avoided. Information on the use of anterior instrumentation along with radical debridement and fusion is scarce. This study reports on the surgical results of 63 patients with Pott's disease who underwent anterior radical debridement with anterior fusion and anterior instrumentation (23 patients with Z-plate and 40 patients with CDH system). Average age at the time of operation was 46.8+/-13.4 years. Average duration of follow-up was 50.9+/-12.9 months. Local kyphosis was measured preoperatively, postoperatively and at the last follow-up visit as the angle between the upper and lower end plates of the collapsed vertebrae. Vertebral collapse, destruction, cold abscess, and canal compromise were assessed on magnetic resonance (MR) images. It was observed that the addition of anterior instrumentation increased the rate of correction of the kyphotic deformity (79.7+/-20.1%), and was effective in maintaining it, with an average loss of 1.1 degrees +/-1.7 degrees. Of the 25 patients (39.7%) with neurological symptoms, 20 (80%) had full and 4 (16%) partial recoveries. There were very few intraoperative and postoperative complications (major vessel complication: 3.2%; secondary non-specific infection: 3.2%). Disease reactivation was not seen with the employment of an aggressive chemotherapy regimen. It was concluded that anterior instrumentation is a safe and effective method in the treatment of tuberculosis

  6. Force-generation and dynamic instability of microtubule bundles

    PubMed Central

    Laan, Liedewij; Husson, Julien; Munteanu, E. Laura; Kerssemakers, Jacob W. J.; Dogterom, Marileen

    2008-01-01

    Individual dynamic microtubules can generate pushing or pulling forces when their growing or shrinking ends are in contact with cellular objects such as the cortex or chromosomes. These microtubules can operate in parallel bundles, for example when interacting with mitotic chromosomes. Here, we investigate the force-generating capabilities of a bundle of growing microtubules and study the effect that force has on the cooperative dynamics of such a bundle. We used an optical tweezers setup to study microtubule bundles growing against a microfabricated rigid barrier in vitro. We show that multiple microtubules can generate a pushing force that increases linearly with the number of microtubules present. In addition, the bundle can cooperatively switch to a shrinking state, due to a force-induced coupling of the dynamic instability of single microtubules. In the presence of GMPCPP, bundle catastrophes no longer occur, and high bundle forces are reached more effectively. We reproduce the observed behavior with a simple simulation of microtubule bundle dynamics that takes into account previously measured force effects on single microtubules. Using this simulation, we also show that a constant compressive force on a growing bundle leads to oscillations in bundle length that are of potential relevance for chromosome oscillations observed in living cells. PMID:18577596

  7. Anterior Repair with Processed Dermis

    MedlinePlus Videos and Cool Tools

    Anterior Repair with Axis® Tutoplast® Processed Dermis and Digitex® - Performed by Dr. Manish Patel Click Here to view the BroadcastMed, Inc. Privacy Policy and Legal Notice © 2016 BroadcastMed, Inc. ...

  8. Anterior Knee Pain (Chondromalacia Patellae).

    ERIC Educational Resources Information Center

    Garrick, James G.

    1989-01-01

    This article presents a pragmatic approach to the definition, diagnosis, and management of anterior knee pain. Symptoms and treatment are described. Emphasis is on active involvement of the patient in the rehabilitation exercise program. (IAH)

  9. Synchronization of Spontaneous Active Motility of Hair Cell Bundles

    PubMed Central

    Zhang, Tracy-Ying; Ji, Seung; Bozovic, Dolores

    2015-01-01

    Hair cells of the inner ear exhibit an active process, believed to be crucial for achieving the sensitivity of auditory and vestibular detection. One of the manifestations of the active process is the occurrence of spontaneous hair bundle oscillations in vitro. Hair bundles are coupled by overlying membranes in vivo; hence, explaining the potential role of innate bundle motility in the generation of otoacoustic emissions requires an understanding of the effects of coupling on the active bundle dynamics. We used microbeads to connect small groups of hair cell bundles, using in vitro preparations that maintain their innate oscillations. Our experiments demonstrate robust synchronization of spontaneous oscillations, with either 1:1 or multi-mode phase-locking. The frequency of synchronized oscillation was found to be near the mean of the innate frequencies of individual bundles. Coupling also led to an improved regularity of entrained oscillations, demonstrated by an increase in the quality factor. PMID:26540409

  10. Synchronization of Spontaneous Active Motility of Hair Cell Bundles.

    PubMed

    Zhang, Tracy-Ying; Ji, Seung; Bozovic, Dolores

    2015-01-01

    Hair cells of the inner ear exhibit an active process, believed to be crucial for achieving the sensitivity of auditory and vestibular detection. One of the manifestations of the active process is the occurrence of spontaneous hair bundle oscillations in vitro. Hair bundles are coupled by overlying membranes in vivo; hence, explaining the potential role of innate bundle motility in the generation of otoacoustic emissions requires an understanding of the effects of coupling on the active bundle dynamics. We used microbeads to connect small groups of hair cell bundles, using in vitro preparations that maintain their innate oscillations. Our experiments demonstrate robust synchronization of spontaneous oscillations, with either 1:1 or multi-mode phase-locking. The frequency of synchronized oscillation was found to be near the mean of the innate frequencies of individual bundles. Coupling also led to an improved regularity of entrained oscillations, demonstrated by an increase in the quality factor. PMID:26540409

  11. Mechanics of Individual Keratin Bundles in Living Cells

    PubMed Central

    Nolting, Jens-Friedrich; Möbius, Wiebke; Köster, Sarah

    2014-01-01

    Along with microtubules and microfilaments, intermediate filaments are a major component of the eukaryotic cytoskeleton and play a key role in cell mechanics. In cells, keratin intermediate filaments form networks of bundles that are sparser in structure and have lower connectivity than, for example, actin networks. Because of this, bending and buckling play an important role in these networks. Buckling events, which occur due to compressive intracellular forces and cross-talk between the keratin network and other cytoskeletal components, are measured here in situ. By applying a mechanical model for the bundled filaments, we can access the mechanical properties of both the keratin bundles themselves and the surrounding cytosol. Bundling is characterized by a coupling parameter that describes the strength of the linkage between the individual filaments within a bundle. Our findings suggest that coupling between the filaments is mostly complete, although it becomes weaker for thicker bundles, with some relative movement allowed. PMID:25468348

  12. The proteome of mouse vestibular hair bundles over development

    PubMed Central

    Krey, Jocelyn F.; Sherman, Nicholas E.; Jeffery, Erin D; Choi, Dongseok; Barr-Gillespie, Peter G.

    2015-01-01

    Development of the vertebrate hair bundle is a precisely orchestrated event that culminates in production of a tightly ordered arrangement of actin-rich stereocilia and a single axonemal kinocilium. To understand how the protein composition of the bundle changes during development, we isolated bundles from young (postnatal days P4-P6) and mature (P21-P25) mouse utricles using the twist-off method, then characterized their constituent proteins using liquid-chromatography tandem mass spectrometry with data-dependent acquisition. Using MaxQuant and label-free quantitation, we measured relative abundances of proteins in both bundles and in the whole utricle; comparison of protein abundance between the two fractions allows calculation of enrichment in bundles. These data, which are available via ProteomeXchange with identifier PXD002167, will be useful for examining the proteins present in mammalian vestibular bundles and how their concentrations change over development. PMID:26401315

  13. Historical dynamics in ecosystem service bundles.

    PubMed

    Renard, Delphine; Rhemtulla, Jeanine M; Bennett, Elena M

    2015-10-27

    Managing multiple ecosystem services (ES), including addressing trade-offs between services and preventing ecological surprises, is among the most pressing areas for sustainability research. These challenges require ES research to go beyond the currently common approach of snapshot studies limited to one or two services at a single point in time. We used a spatiotemporal approach to examine changes in nine ES and their relationships from 1971 to 2006 across 131 municipalities in a mixed-use landscape in Quebec, Canada. We show how an approach that incorporates time and space can improve our understanding of ES dynamics. We found an increase in the provision of most services through time; however, provision of ES was not uniformly enhanced at all locations. Instead, each municipality specialized in providing a bundle (set of positively correlated ES) dominated by just a few services. The trajectory of bundle formation was related to changes in agricultural policy and global trends; local biophysical and socioeconomic characteristics explained the bundles' increasing spatial clustering. Relationships between services varied through time, with some provisioning and cultural services shifting from a trade-off or no relationship in 1971 to an apparent synergistic relationship by 2006. By implementing a spatiotemporal perspective on multiple services, we provide clear evidence of the dynamic nature of ES interactions and contribute to identifying processes and drivers behind these changing relationships. Our study raises questions about using snapshots of ES provision at a single point in time to build our understanding of ES relationships in complex and dynamic social-ecological systems. PMID:26460005

  14. Systematic Bundle Adjustment of HRSC Image Data

    NASA Astrophysics Data System (ADS)

    Bostelmann, J.; Schmidt, R.; Heipke, C.

    2012-07-01

    The European Mars Express mission was launched in June 2003 and sent into orbit around Mars. On board the orbiter is the German High Resolution Stereo Camera (HRSC). This multi-line sensor images the Martian surface with a resolution of up to 12m per pixel in three dimensions and provides RGB and infra-red color information. The usage of the stereoscopic image information for the improvement of the observed position and attitude information via bundle adjustment is important to derive high quality 3D surface models, color orthoimages and other data products. In many cases overlapping image strips of different orbits can be used to form photogrammetric blocks, thus allowing the simultaneous adjustment of the exterior orientation data. This reduces not only local, but also regional inconsistencies in the data. With the growing number of HRSC image strips in this ongoing mission, the size and complexity of potential blocks is increasing. Therefore, a workflow has been built up for the systematic improvement of the exterior orientation using single orbit strips and regional blocks. For a successful bundle adjustment of blocks using multiple image strips a sufficient number of tie points in the overlapping area is needed. The number of tie points depends mainly on the geometric and radiometric quality of the images. This is considered by detailed analysis of the tie point accuracy and distribution. The combination of methods for image pre-processing, tie point matching, bundle adjustment and evaluation of the results in an automated workflow allows for all HRSC images a global assessment of the quality and a systematic selection of data for larger blocks.

  15. Chemical vapor infiltration of carbon fiber bundles

    SciTech Connect

    Currier, R.P.; Devlin, D.J.; Barbero, R.S.

    1992-12-31

    Chemical vapor infiltration in carbon fiber bundles is studied under isothermal conditions over the temperature range 1000--1090 C at a nominal pressure of 300 Torr. Pyrolytic decomposition of methane is used in the infiltration experiments with carbon weight gain data obtained continuously from thermogravimetric analysis. The sensitivity of the infiltration dynamics to initial yarn porosity and to spatial variations in fiber positioning are explored. Results indicate that small changes in initial porosity can have significant impact on the weight gain above the solid phase percolation threshold.

  16. Chemical vapor infiltration of carbon fiber bundles

    SciTech Connect

    Currier, R.P.; Devlin, D.J.; Barbero, R.S.

    1992-01-01

    Chemical vapor infiltration in carbon fiber bundles is studied under isothermal conditions over the temperature range 1000--1090 C at a nominal pressure of 300 Torr. Pyrolytic decomposition of methane is used in the infiltration experiments with carbon weight gain data obtained continuously from thermogravimetric analysis. The sensitivity of the infiltration dynamics to initial yarn porosity and to spatial variations in fiber positioning are explored. Results indicate that small changes in initial porosity can have significant impact on the weight gain above the solid phase percolation threshold.

  17. Compression of a bundle of light rays.

    PubMed

    Marcuse, D

    1971-03-01

    The performance of ray compression devices is discussed on the basis of a phase space treatment using Liouville's theorem. It is concluded that the area in phase space of the input bundle of rays is determined solely by the required compression ratio and possible limitations on the maximum ray angle at the output of the device. The efficiency of tapers and lenses as ray compressors is approximately equal. For linear tapers and lenses the input angle of the useful rays must not exceed the compression ratio. The performance of linear tapers and lenses is compared to a particular ray compressor using a graded refractive index distribution. PMID:20094478

  18. Bohr-Sommerfeld Lagrangians of moduli spaces of Higgs bundles

    NASA Astrophysics Data System (ADS)

    Biswas, Indranil; Gammelgaard, Niels Leth; Logares, Marina

    2015-08-01

    Let X be a compact connected Riemann surface of genus at least two. Let MH(r, d) denote the moduli space of semistable Higgs bundles on X of rank r and degree d. We prove that the compact complex Bohr-Sommerfeld Lagrangians of MH(r, d) are precisely the irreducible components of the nilpotent cone in MH(r, d) . This generalizes to Higgs G-bundles and also to the parabolic Higgs bundles.

  19. Evaluation of the effect of joint constraints on the in situ force distribution in the anterior cruciate ligament.

    PubMed

    Livesay, G A; Rudy, T W; Woo, S L; Runco, T J; Sakane, M; Li, G; Fu, F H

    1997-03-01

    The function of the anterior cruciate ligament was investigated for different conditions of kinematic constraint placed on the intact knee using a six-degree-of-freedom robotic manipulator combined with a universal force-moment sensor. To do this, the in situ forces and force distribution within the porcine anterior cruciate ligament during anterior tibial loading up to 100 N were compared at 30, 60, and 90 degrees of flexion under: (a) unconstrained, five-degree-of-freedom knee motion, and (b) constrained, one-degree-of-freedom motion (i.e., anterior translations only). The robotic/universal force-moment sensor testing system was used to both apply the specified external loading to the intact joint and measure the resulting kinematics. After tests of the intact knee were completed, all soft tissues except the anterior cruciate ligament were removed, and these motions were reproduced such that the in situ force and force distribution could be determined. No significant differences in the magnitude of in situ forces in the anterior cruciate ligament were found between the unconstrained and constrained testing conditions. In contrast, the direction of in situ force changed significantly; the force vector in the unconstrained case was more parallel with the direction of the applied tibial load. In addition, the distribution of in situ force between the anteromedial and posterolateral bundles of the ligament was nearly equal for all flexion angles for the unconstrained case, whereas the anteromedial bundle carried higher forces than the posterolateral bundle at both 60 and 90 degrees of flexion for the constrained case. This demonstrates that the constraint conditions placed on the joint have a significant effect on the apparent role of the anterior cruciate ligament. Specifically, constraining joint motion to one degree of freedom significantly alters both the direction and distribution of the in situ force in the ligament from that observed for unconstrained joint

  20. Robust Mapping of Incoherent Fiber-Optic Bundles

    NASA Technical Reports Server (NTRS)

    Roberts, Harry E.; Deason, Brent E.; DePlachett, Charles P.; Pilgrim, Robert A.; Sanford, Harold S.

    2007-01-01

    A method and apparatus for mapping between the positions of fibers at opposite ends of incoherent fiber-optic bundles have been invented to enable the use of such bundles to transmit images in visible or infrared light. The method is robust in the sense that it provides useful mapping even for a bundle that contains thousands of narrow, irregularly packed fibers, some of which may be defective. In a coherent fiber-optic bundle, the input and output ends of each fiber lie at identical positions in the input and output planes; therefore, the bundle can be used to transmit images without further modification. Unfortunately, the fabrication of coherent fiber-optic bundles is too labor-intensive and expensive for many applications. An incoherent fiber-optic bundle can be fabricated more easily and at lower cost, but it produces a scrambled image because the position of the end of each fiber in the input plane is generally different from the end of the same fiber in the output plane. However, the image transmitted by an incoherent fiber-optic bundle can be unscrambled (or, from a different perspective, decoded) by digital processing of the output image if the mapping between the input and output fiber-end positions is known. Thus, the present invention enables the use of relatively inexpensive fiber-optic bundles to transmit images.

  1. Force-strain relation of bundles of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Xiao, Tan; Ren, Yu; Wu, Ping; Liao, Kin

    2006-07-01

    The force-strain relation and tensile strength of carbon nanotube bundles are studied based on the assumption that the tensile strength of individual carbon nanotubes (CNTs) obeys the Weibull distribution, with nonlinear stress-strain behavior. The Weibull modulus of the CNT that characterizes the dispersion of tensile strength can be estimated in terms of the maximum sustained force and the failure strain of the bundle. Bundles of single-walled carbon nanotubes (SWNTs) were subjected to tensile testing using a nanomechanical testing device. Results show that the nonlinear behavior of SWNTs does affect the force-strain relation of SWNT bundles, more apparent at large strain.

  2. Bundle formation in parallel aligned polymers with competing interactions

    NASA Astrophysics Data System (ADS)

    Dutta, Sandipan; Benetatos, P.; Jho, Y. S.

    2016-04-01

    Aggregation of like-charged polymers is widely observed in biological- and soft-matter systems. In many systems, bundles are formed when a short-range attraction of diverse physical origin like charge bridging, hydrogen bonding or hydrophobic interaction, overcomes the longer-range charge repulsion. In this letter, we present a general mechanism of bundle formation in these systems as the breaking of the translational invariance in parallel aligned polymers with competing interactions of this type. We derive a criterion for finite-sized bundle formation as well as for macroscopic phase separation (formation of infinite bundles).

  3. Myocardial blood flow assessment with 82rubidium-PET imaging in patients with left bundle branch block

    PubMed Central

    Falcão, Andréa; Chalela, William; Giorgi, Maria Clementina; Imada, Rodrigo; Soares, José; Do Val, Renata; Oliveira, Marco Antonio; Izaki, Marisa; Filho, Roberto Kalil; Meneghetti, José C

    2015-01-01

    OBJECTIVES: Perfusion abnormalities are frequently seen in Single Photon Emission Computed Tomography (SPECT) when a left bundle branch block is present. A few studies have shown decreased coronary flow reserve in the left anterior descending territory, regardless of the presence of coronary artery disease. OBJECTIVE: We sought to investigate rubidium-82 (82Rb) positron emission tomography imaging in the assessment of myocardial blood flow and coronary flow reserve in patients with left bundle branch block. METHODS: Thirty-eight patients with left bundle branch block (GI), median age 63.5 years, 22 (58%) female, 12 with coronary artery disease (≥70%; GI-A) and 26 with no evidence of significant coronary artery disease (GI-B), underwent rest-dipyridamole stress 82Rb-positron emission tomography with absolute quantitative flow measurements using Cedars-Sinai software (mL/min/g). The relative myocardial perfusion and left ventricular ejection fraction were assessed in 17 segments. These parameters were compared with those obtained from 30 patients with normal 82Rb-positron emission tomography studies and without left bundle branch block (GII). RESULTS: Stress myocardial blood flow and coronary flow reserve were significantly lower in GI than in GII (p<0.05). The comparison of coronary flow reserve between GI-A and GI-B showed that it was different from the global coronary flow reserve (p<0.05) and the stress flow was significantly lower in the anterior than in the septal wall for both groups. Perfusion abnormalities were more prevalent in GI-A (p=0.06) and the left ventricular ejection fraction was not different between GI-A and GI-B, whereas it was lower in GI than in GII (p<0.001). CONCLUSION: The data confirm that patients with left bundle branch block had decreased myocardial blood flow and coronary flow reserve and coronary flow reserve assessed by 82Rb-positron emission tomography imaging may be useful in identifying coronary artery disease in patients with

  4. Constrained ripple optimization of Tokamak bundle divertors

    SciTech Connect

    Hively, L.M.; Rome, J.A.; Lynch, V.E.; Lyon, J.F.; Fowler, R.H.; Peng, Y-K.M.; Dory, R.A.

    1983-02-01

    Magnetic field ripple from a tokamak bundle divertor is localized to a small toroidal sector and must be treated differently from the usual (distributed) toroidal field (TF) coil ripple. Generally, in a tokamak with an unoptimized divertor design, all of the banana-trapped fast ions are quickly lost due to banana drift diffusion or to trapping between the 1/R variation in absolute value vector B ..xi.. B and local field maxima due to the divertor. A computer code has been written to optimize automatically on-axis ripple subject to these constraints, while varying up to nine design parameters. Optimum configurations have low on-axis ripple (<0.2%) so that, now, most banana-trapped fast ions are confined. Only those ions with banana tips near the outside region (absolute value theta < or equal to 45/sup 0/) are lost. However, because finite-sized TF coils have not been used in this study, the flux bundle is not expanded.

  5. Tangent Bundle Elastica and Computer Vision.

    PubMed

    Ben-Shahar, Ohad; Ben-Yosef, Guy

    2015-01-01

    Visual curve completion, an early visual process that completes the occluded parts between observed boundary fragments (a.k.a. inducers), is a major problem in perceptual organization and a critical step toward higher level visual tasks in both biological and machine vision. Most computational contributions to solving this problem suggest desired perceptual properties that the completed contour should satisfy in the image plane, and then seek the mathematical curves that provide them. Alternatively, few studies (including by the authors) have suggested to frame the problem not in the image plane but rather in the unit tangent bundleR (2) × S(1), the space that abstracts the primary visual cortex, where curve completion allegedly occurs. Combining both schools, here we propose and develop a biologically plausible theory of elastica in the tangent bundle that provides not only perceptually superior completion results but also a rigorous computational prediction that inducer curvatures greatly affects the shape of the completed curve, as indeed indicated by human perception. PMID:26353216

  6. Development boiling to sprinkled tube bundle

    NASA Astrophysics Data System (ADS)

    Kracík, Petr; Pospíšil, Jiří

    2016-03-01

    This paper presents results of a studied heat transfer coefficient at the surface of a sprinkled tube bundle where boiling occurs. Research in the area of sprinkled exchangers can be divided into two major parts. The first part is research on heat transfer and determination of the heat transfer coefficient at sprinkled tube bundles for various liquids, whether boiling or not. The second part is testing of sprinkle modes for various tube diameters, tube pitches and tube materials and determination of individual modes' interface. All results published so far for water as the falling film liquid apply to one to three tubes for which the mentioned relations studied are determined in rigid laboratory conditions defined strictly in advance. The sprinkled tubes were not viewed from the operational perspective where there are more tubes and various modes may occur in different parts with various heat transfer values. The article focuses on these processes. The tube is located in a low-pressure chamber where vacuum is generated using an exhauster via ejector. The tube consists of smooth copper tubes of 12 mm diameter placed horizontally one above another.

  7. Emitters of N-photon bundles

    NASA Astrophysics Data System (ADS)

    Muñoz, C. Sánchez; Del Valle, E.; Tudela, A. González; Müller, K.; Lichtmannecker, S.; Kaniber, M.; Tejedor, C.; Finley, J. J.; Laussy, F. P.

    2014-07-01

    Controlling the output of a light emitter is one of the basic tasks in photonics, with landmarks such as the development of the laser and single-photon sources. The ever growing range of quantum applications is making it increasingly important to diversify the available quantum sources. Here, we propose a cavity quantum electrodynamics scheme to realize emitters that release their energy in groups (or `bundles') of N photons (where N is an integer). Close to 100% of two-photon emission and 90% of three-photon emission is shown to be within reach of state-of-the-art samples. The emission can be tuned with the system parameters so that the device behaves as a laser or as an N-photon gun. Here, we develop the theoretical formalism to characterize such emitters, with the bundle statistics arising as an extension of the fundamental correlation functions of quantum optics. These emitters will be useful for quantum information processing and for medical applications.

  8. Confinement-dependent friction in peptide bundles.

    PubMed

    Erbaş, Aykut; Netz, Roland R

    2013-03-19

    Friction within globular proteins or between adhering macromolecules crucially determines the kinetics of protein folding, the formation, and the relaxation of self-assembled molecular systems. One fundamental question is how these friction effects depend on the local environment and in particular on the presence of water. In this model study, we use fully atomistic MD simulations with explicit water to obtain friction forces as a single polyglycine peptide chain is pulled out of a bundle of k adhering parallel polyglycine peptide chains. The whole system is periodically replicated along the peptide axes, so a stationary state at prescribed mean sliding velocity V is achieved. The aggregation number is varied between k = 2 (two peptide chains adhering to each other with plenty of water present at the adhesion sites) and k = 7 (one peptide chain pulled out from a close-packed cylindrical array of six neighboring peptide chains with no water inside the bundle). The friction coefficient per hydrogen bond, extrapolated to the viscous limit of vanishing pulling velocity V → 0, exhibits an increase by five orders of magnitude when going from k = 2 to k = 7. This dramatic confinement-induced friction enhancement we argue to be due to a combination of water depletion and increased hydrogen-bond cooperativity. PMID:23528088

  9. Anterior Orbit and Adnexal Amyloidosis

    PubMed Central

    Al Hussain, Hailah; Edward, Deepak P.

    2013-01-01

    Purpose: To describe six cases of anterior orbital and adnexal amyloidosis and to report on proteomic analysis to characterize the nature of amyloid in archived biopsies in two cases. Materials and Methods: The clinical features, radiological findings, pathology, and outcome of six patients with anterior orbit and adnexal amyloidosis were retrieved from the medical records. The biochemical nature of the amyloid was determined using liquid chromatography/mass spectroscopy archived paraffin-embedded tissue in two cases. Results: Of the six cases, three had unilateral localized anterior orbit and lacrimal gland involvement. Four of the six patients were female with an average duration of 12.8 years from the time of onset to presentation eyelid infiltration by amyloid caused ptosis in five cases. CT scan in patients with lacrimal gland involvement (n = 3) demonstrated calcified deformable anterior orbital masses and on pathological exmaintionamyloid and calcific deposits replaced the lacrimal gland acini. Ptosis repair was performed in three patients with good outcomes. One patient required repeated debulking of the mass and one patient had recurrenct disease. Proteomic analysis revealed polyclonal IgG-associated amyloid deposition in one patient and AL kappa amyloid in the second patient. Conclusion: Amyloidosis of the anterior orbit and lacrimal gland can present with a wide spectrum of findings with good outcomes after surgical excision. The nature of amyloid material can be precisely determined in archival pathology blocks using diagnostic proteomic analysis. PMID:24014979

  10. Combined posterior flap and anterior suspended flap dacryocystorhinostomy: A modification of external dacryocystorhinostomy

    PubMed Central

    Deka, Amarendra; Saikia, S. P.; Bhuyan, S. K.

    2010-01-01

    Background: External dacryocystorhinostomy (DCR) remains a reliable surgical technique for the treatment of obstruction of lacrimal drainage system beyond the common canalicular opening. Aim: To describe a simple modified double flap external DCR technique. Materials and Methods: Ninety six consecutive cases of chronic dacryocystitis with or without mucocele were selected irrespective of age and sex. In a modification to routine external DCR, a modified technique was followed, where both anterior and posterior flaps of lacrimal sac and nasal mucosa are created and sutured. Two double armed sutures were used to join the edges of anterior flaps, and elevate them anteriorly to avoid adhesion or apposition with underlying sutured posterior flaps, and to approximate the deep plane of the wound. Results: At the end of average follow-up period of 13 months, we observed 98.9% objective and 96.8% subjective success rates. The average operation time was 45 minutes. No significant intraoperative or postoperative complications were noticed. Conclusion: We believe that combined posterior flap and anterior suspended flap DCR technique is simple to perform and has the advantage of both double flap DCR and anterior suspension of anterior flaps. The results of the study showed the efficacy of this simple modification. PMID:20606867

  11. RNase sensitivity of an anterior morphogenetic determinant in an insect egg (Smittia sp., Chironomidae, Diptera).

    PubMed Central

    Kandler-Singer, I; Kalthoff, K

    1976-01-01

    In chironomid midges, the development of head and thorax in the embryo requires the function of cytoplasmic determinants localized near the anterior pole of the egg. Experimental inactivation of these determinants causes a dramatic switch in the developmental program of the embryo. Instead of the normal segment pattern, the aberrant pattern "double abdomen" is formed. Head, thorax, and anterior abdominal segments are then replaced by an additional set of posterior abdominal segments joined in mirror image symmetry to the original abdomen. Such double abdomens have been produced, with a maximum yield of 29%, by application of RNase (ribonuclease I, ribonucleate 3'-pyrimidino-oligonucleotidohydrolase, EC 3.1.4.22) to the anterior pole region of the egg. This was achieved by microinjection or puncturing the eggs during submersion in RNase. Control experiments with inactive RNase S fragments reliably proved that double abdomen formation resulted from RNase activity. Neither application of other enzymes to the anterior pole region nor application of RNase to other egg regions produced double abdomens in significant yields. The effects of RNase concentration and stage of development were determined. The data from these and earlier experiments are compatible with the idea that stored cytoplasmic RNP particles act as anterior determinants. Similarities to genetically caused switches in developmental pathways (homeotic mutations) are discussed. Images PMID:1068484

  12. Hair bundle profiles along the chick basilar papilla

    PubMed Central

    DUNCAN, R. K.; ILE, K. E.; DUBIN, M. G.; SAUNDERS, J. C.

    2001-01-01

    Cochlear hair cells play a central role in the transduction of sound into neural output. Anatomical descriptions of these cells, and their protruding hair bundles, are of fundamental interest since hair cell transduction is dependent on hair bundle micromechanics and hair bundle micromechanics depends on hair bundle morphology. In this paper, we describe quantitatively changes in the staircase profile of the hair bundle along the apical portion of the chick's basilar papilla. Images of hair cells from 8 discretely dissected segments of the apical 3rd of the basilar papilla were archived, and the profile contour outlined by the tips of the stereocilia was digitised and curves were fitted by linear and power equations. The hair bundles of tall hair cells exhibited both linear and curvilinear profiles, which were equally distributed along the papilla. All short hair cells in our sample had straight contours. The differences in hair bundle shape among the tall hair cells may lead to differential susceptibility to injury and some variance in the current-displacement transduction curves due to differences in the translation of forces throughout the hair bundle. PMID:11215761

  13. Molecular Architecture of the Chick Vestibular Hair Bundle

    PubMed Central

    Shin, Jung-Bum; Krey, Jocelyn F.; Hassan, Ahmed; Metlagel, Zoltan; Tauscher, Andrew N.; Pagana, James M.; Sherman, Nicholas E.; Jeffery, Erin D.; Spinelli, Kateri J.; Zhao, Hongyu; Wilmarth, Phillip A.; Choi, Dongseok; David, Larry L.; Auer, Manfred; Barr-Gillespie, Peter G.

    2012-01-01

    Hair bundles of the inner ear have a unique structure and protein composition that underlies their sensitivity to mechanical stimulation. Using mass spectrometry, we identified and quantified >1100 proteins, present from a few to 400,000 copies per stereocilium, from purified chick bundles; 336 of these were significantly enriched in bundles. Bundle proteins that we detected have been shown to regulate cytoskeleton structure and dynamics, energy metabolism, phospholipid synthesis, and cell signaling. Three-dimensional imaging using electron tomography allowed us to count the number of actin-actin crosslinkers and actin-membrane connectors; these values compared well to those obtained from mass spectrometry. Network analysis revealed several hub proteins, including RDX (radixin) and SLC9A3R2 (NHERF2), which interact with many bundle proteins and may perform functions essential for bundle structure and function. The quantitative mass spectrometry of bundle proteins reported here establishes a framework for future characterization of dynamic processes that shape bundle structure and function. PMID:23334578

  14. Molecular architecture of the chick vestibular hair bundle.

    PubMed

    Shin, Jung-Bum; Krey, Jocelyn F; Hassan, Ahmed; Metlagel, Zoltan; Tauscher, Andrew N; Pagana, James M; Sherman, Nicholas E; Jeffery, Erin D; Spinelli, Kateri J; Zhao, Hongyu; Wilmarth, Phillip A; Choi, Dongseok; David, Larry L; Auer, Manfred; Barr-Gillespie, Peter G

    2013-03-01

    Hair bundles of the inner ear have a specialized structure and protein composition that underlies their sensitivity to mechanical stimulation. Using mass spectrometry, we identified and quantified >1,100 proteins, present from a few to 400,000 copies per stereocilium, from purified chick bundles; 336 of these were significantly enriched in bundles. Bundle proteins that we detected have been shown to regulate cytoskeleton structure and dynamics, energy metabolism, phospholipid synthesis and cell signaling. Three-dimensional imaging using electron tomography allowed us to count the number of actin-actin cross-linkers and actin-membrane connectors; these values compared well to those obtained from mass spectrometry. Network analysis revealed several hub proteins, including RDX (radixin) and SLC9A3R2 (NHERF2), which interact with many bundle proteins and may perform functions essential for bundle structure and function. The quantitative mass spectrometry of bundle proteins reported here establishes a framework for future characterization of dynamic processes that shape bundle structure and function. PMID:23334578

  15. Amplitude death of coupled hair bundles with stochastic channel noise

    NASA Astrophysics Data System (ADS)

    Kim, Kyung-Joong; Ahn, Kang-Hun

    2014-04-01

    Hair cells conduct auditory transduction in vertebrates. In lower vertebrates such as frogs and turtles, due to the active mechanism in hair cells, hair bundles (stereocilia) can be spontaneously oscillating or quiescent. Recently an amplitude death phenomenon has been proposed [K.-H. Ahn, J. R. Soc. Interface, 10, 20130525 (2013)] as a mechanism for auditory transduction in frog hair-cell bundles, where sudden cessation of the oscillations arises due to the coupling between nonidentical hair bundles. The gating of the ion channel is intrinsically stochastic due to the stochastic nature of the configuration change of the channel. The strength of the noise due to the channel gating can be comparable to the thermal Brownian noise of hair bundles. Thus, we perform stochastic simulations of the elastically coupled hair bundles. In spite of stray noisy fluctuations due to its stochastic dynamics, our simulation shows the transition from collective oscillation to amplitude death as interbundle coupling strength increases. In its stochastic dynamics, the formation of the amplitude death state of coupled hair bundles can be seen as a sudden suppression of the displacement fluctuation of the hair bundles as the coupling strength increases. The enhancement of the signal-to-noise ratio through the amplitude death phenomenon is clearly seen in the stochastic dynamics. Our numerical results demonstrate that the multiple number of transduction channels per hair bundle is an important factor to the amplitude death phenomenon, because the phenomenon may disappear for a small number of transduction channels due to strong gating noise.

  16. Bundled slaty cleavage in laminated argillite, north-central minnesota

    USGS Publications Warehouse

    Southwick, D.L.

    1987-01-01

    Exceptional bundled slaty cleavage (defined herein) has been found in drill cores of laminated, folded, weakly metamorphosed argillite at several localities in the early Proterozoic Animikie basin of north-central Minnesota. The cleavage domains are more closely spaced within the cleavage bundles than outside them, the mean tectosilicate grain size of siltstone layers, measured normal to cleavage, is less in the cleavage bundles than outside them, and the cleavage bundles are enriched in opaque phases and phyllosilicates relative to extra-bundle segments. These facts suggest that pressure solution was a major factor in bundle development. If it is assumed that opaque phases have been conserved during pressure solution, the modal differences in composition between intra-bundle and extra-bundle segments of beds provide a means for estimating bulk material shortening normal to cleavage. Argillite samples from the central part of the Animikie basin have been shortened a minimum of about 22%, as estimated by this method. These estimates are similar to the shortening values derived from other strain markers in other rock types interbedded with the argillite, and are also consistent with the regional pattern of deformation. ?? 1987.

  17. Properties of microtubule bundles induced by Glyceraldehyde-3-phosphate dehydrogenase

    NASA Astrophysics Data System (ADS)

    Somers, Marijke; Engelborghs, Yves

    1991-05-01

    The binding of Glyceraldehyde-3-phosphate dehydrogenase (GAPDH; E.C. 1.2.1.12) to microtubules causes the microtubules to assemble into large bundles. This bundling can be considered as a further step in the assembly of supramolecular structures. The rate of bundle formation, after addition of GAPDH to preformed microtubules, is not dependent on the GAPDH concentration and reflects bundling kinetics. Bundle disassembly can be studied by the addition of 1 mM adenosine 5'-(β, -imidotri-phosphate) (AMPPNP) to bundled microtubules, and is extremely fast. Bundling reduces the rate of association of tubulin dimers to microtubules, as well as the dissocation from the microtubles. Both rates are reduced to the same extent. This is in agreement with the fact that the critical concentration of tubulin is practically not influenced by the binding of the enzyme. Adding microtubule associated proteins (at I=0.1 M) does not appreciably influence the affinity for GAPDH, but reduces bundle formation possibly for sterical reasons.

  18. Lexical Bundles: Facilitating University "Talk" in Group Discussions

    ERIC Educational Resources Information Center

    Heng, Chan Swee; Kashiha, Hadi; Tan, Helen

    2014-01-01

    Group discussion forms an integral language experience for most language learners, providing them with an opportunity to express themselves in a naturalistic setting. Multi-word expressions are commonly used and one of them is lexical bundles. Lexical bundles are types of extended collocations that occur more commonly than we expect; they are…

  19. His bundle pacing: Initial experience and lessons learned.

    PubMed

    Deshmukh, Amrish; Deshmukh, Pramod

    2016-01-01

    Direct His bundle pacing provides the most physiologic means of artificial pacing of the ventricles with a preserved His-Purkinje system and may play a role in patients with a diseased intrinsic conduction system. We describe our initial motivations and experience with permanent direct His bundle pacing and important lessons learned since that time. PMID:27591359

  20. 76 FR 61365 - Bundled Payments for Care Improvement Initiative

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-04

    ... 25, 2011 we published a notice requesting applications in the Federal Register [76 FR 53137] to... HUMAN SERVICES Centers for Medicare & Medicaid Services Bundled Payments for Care Improvement Initiative.... SUMMARY: This notice extends the deadlines for the submission of the Bundled Payments for Care...

  1. Targeted Anterior Gland Focal Therapy-a Novel Treatment Option for a Better Defined Disease.

    PubMed

    Tay, Kae Jack; Villers, Arnauld; Polascik, Thomas J

    2016-10-01

    The goal of focal therapy is to achieve long-term oncological control by eradicating only the clinically significant focus/foci of cancer within the prostate, while preserving erectile function and continence. Anterior prostate cancers may have a PZ or TZ origin and share commonalities in location and biology. While anterior prostate cancers previously constituted a diagnostic blind spot in the prostate and were often not detected or discovered late, with the rapid dissemination of advanced imaging and biopsy techniques, they can now be identified at an earlier, organ-confined stage due to MR imaging and targeted biopsies. Due to their anterior location, they represent a therapeutic target that allows for thorough ablation of the cancer focus/foci with an adequate margin while remaining far from the neurovascular bundles bilaterally. However, the TZ origin cancers are mostly anterior to the distal urethra close to the apex and the striated sphincter. Men having early stage anterior cancers may represent good candidates to achieve a balance between oncological control and functional preservation with focal therapy. Thus, this class of tumor based on location, along with the proposed treatment, represents a novel form of targeted image-guided therapy. PMID:27502428

  2. Bundling of bovine and brine shrimp (Artemia) microtubules in vitro.

    PubMed

    MacRae, T H

    1984-06-01

    Cell-free extracts from embryos of the brine shrimp (Artemia) induced bundling of bovine microtubules assembled in the presence of glycerol and Mg++. Sedimentation of microtubules through sucrose cushions and subsequent electrophoresis revealed that bundling occurred independently of accessory proteins tightly bound to the microtubules. Bovine microtubules containing microtubule-associated proteins (MAPS) or assembled with taxol did not bundle. The unusual polymerization properties of homogeneous Artemia tubulin, bundling in the absence of added factors and the small number of microtubules assembled in crude embryo extracts upon addition of taxol precluded a complete comparative study of Artemia and bovine microtubule bundling. Interesting properties of the in vitro assembly of Artemia microtubules were, however, elaborated and putative Artemia MAPs were observed as a consequence of the work with brine shrimp embryos. PMID:6744423

  3. Assembly of hair bundles, an amazing problem for cell biology.

    PubMed

    Barr-Gillespie, Peter-G

    2015-08-01

    The hair bundle--the sensory organelle of inner-ear hair cells of vertebrates--exemplifies the ability of a cell to assemble complex, elegant structures. Proper construction of the bundle is required for proper mechanotransduction in response to external forces and to transmit information about sound and movement. Bundles contain tightly controlled numbers of actin-filled stereocilia, which are arranged in defined rows of precise heights. Indeed, many deafness mutations that disable hair-cell cytoskeletal proteins also disrupt bundles. Bundle assembly is a tractable problem in molecular and cellular systems biology; the sequence of structural changes in stereocilia is known, and a modest number of proteins may be involved. PMID:26229154

  4. Voltage- and calcium-dependent motility of saccular hair bundles

    NASA Astrophysics Data System (ADS)

    Quiñones, Patricia M.; Meenderink, Sebastiaan W. F.; Bozovic, Dolores

    2015-12-01

    Active bundle motility, which is hypothesized to supply feedback for mechanical amplification of signals, is thought to enhance sensitivity and sharpen tuning in vestibular and auditory organs. To study active hair bundle motility, we combined high-speed camera recordings of bullfrog sacculi, which were mounted in a two-compartment chamber, and voltage-clamp of the hair cell membrane potential. Using this paradigm, we measured three types of bundle motions: 1) spontaneous oscillations which can be analyzed to measure the physiological operating range of the transduction channel; 2) a sustained quasi-static movement of the bundle that depends on membrane potential; and 3) a fast, transient and asymmetric movement that resets the bundle position and depends on changes in the membrane potential. These data support a role for both calcium and voltage in the transduction-channel function.

  5. Genetic algorithm for bundle adjustment in aerial panoramic stitching

    NASA Astrophysics Data System (ADS)

    Zhang, Chunxiao; Wen, Gaojin; Wu, Chunnan; Wang, Hongmin; Shang, Zhiming; Zhang, Qian

    2015-03-01

    This paper presents a genetic algorithm for bundle adjustment in aerial panoramic stitching. Compared with the conventional LM (Levenberg-Marquardt) algorithm for bundle adjustment, the proposed bundle adjustment combining the genetic algorithm optimization eliminates the possibility of sticking into the local minimum, and not requires the initial estimation of desired parameters, naturally avoiding the associated steps, that includes the normalization of matches, the computation of homography transformation, the calculations of rotation transformation and the focal length. Since the proposed bundle adjustment is composed of the directional vectors of matches, taking the advantages of genetic algorithm (GA), the Jacobian matrix and the normalization of residual error are not involved in the searching process. The experiment verifies that the proposed bundle adjustment based on the genetic algorithm can yield the global solution even in the unstable aerial imaging condition.

  6. Vision, healing brush, and fiber bundles

    NASA Astrophysics Data System (ADS)

    Georgiev, Todor

    2005-03-01

    The Healing Brush is a tool introduced for the first time in Adobe Photoshop (2002) that removes defects in images by seamless cloning (gradient domain fusion). The Healing Brush algorithms are built on a new mathematical approach that uses Fibre Bundles and Connections to model the representation of images in the visual system. Our mathematical results are derived from first principles of human vision, related to adaptation transforms of von Kries type and Retinex theory. In this paper we present the new result of Healing in arbitrary color space. In addition to supporting image repair and seamless cloning, our approach also produces the exact solution to the problem of high dynamic range compression of17 and can be applied to other image processing algorithms.

  7. Extendability of parallel sections in vector bundles

    NASA Astrophysics Data System (ADS)

    Kirschner, Tim

    2016-01-01

    I address the following question: Given a differentiable manifold M, what are the open subsets U of M such that, for all vector bundles E over M and all linear connections ∇ on E, any ∇-parallel section in E defined on U extends to a ∇-parallel section in E defined on M? For simply connected manifolds M (among others) I describe the entirety of all such sets U which are, in addition, the complement of a C1 submanifold, boundary allowed, of M. This delivers a partial positive answer to a problem posed by Antonio J. Di Scala and Gianni Manno (2014). Furthermore, in case M is an open submanifold of Rn, n ≥ 2, I prove that the complement of U in M, not required to be a submanifold now, can have arbitrarily large n-dimensional Lebesgue measure.

  8. Geometries and applications of active fiber bundles

    NASA Astrophysics Data System (ADS)

    Giglmayr, Josef

    2001-10-01

    Active fiber bundles (FBs) are aimed to model photonic switching and processing in 3-D without the restrictions of the photonic technology. The 2-D photonic architectures are assumed to be implemented by networks of directional couplers (DCs) and Mach-Zehnder interferometers (MZIs), respectively. For the implementation several crucial problems are expected: (1) proper operation of the spatial couplers/switches (nonblocking interconnections) and (2) coupling in the interstage interconnection section mainly caused by parallel and crossing fibers/waveguides (WGs). For the design of proper operating switches (refinement of couplers) the application of decoupling concepts of modern control theory is proposed. The final goal is to translate the refined couplers into integrated photonic architectures rather than into additional lightwave circuits (LWCs) which simply would increase the coupling. The decoupling concepts are reviewed. The paper is an attempt to prepare for applying well-known system engineering concepts to the upcoming technology of photonics.

  9. Advanced tube-bundle rocket thrust chamber

    NASA Technical Reports Server (NTRS)

    Kazaroff, John M.; Pavli, Albert J.

    1990-01-01

    An advanced rocket thrust chamber for future space application is described along with an improved method of fabrication. Potential benefits of the concept are improved cyclic life, reusability, and performance. Performance improvements are anticipated because of the enhanced heat transfer into the coolant which will enable higher chamber pressure in expander cycle engines. Cyclic life, reusability and reliability improvements are anticipated because of the enhanced structural compliance inherent in the construction. The method of construction involves the forming of the combustion chamber with a tube-bundle of high conductivity copper or copper alloy tubes, and the bonding of these tubes by an electroforming operation. Further, the method of fabrication reduces chamber complexity by incorporating manifolds, jackets, and structural stiffeners while having the potential for thrust chamber cost and weight reduction.

  10. Emitters of N-photon bundles

    PubMed Central

    Muñoz, C. Sánchez; del Valle, E.; Tudela, A. González; Müller, K.; Lichtmannecker, S.; Kaniber, M.; Tejedor, C.; Finley, J.J.; Laussy, F.P.

    2014-01-01

    Controlling the ouput of a light emitter is one of the basic tasks of photonics, with landmarks such as the laser and single-photon sources. The development of quantum applications makes it increasingly important to diversify the available quantum sources. Here, we propose a cavity QED scheme to realize emitters that release their energy in groups, or “bundles” of N photons, for integer N. Close to 100% of two-photon emission and 90% of three-photon emission is shown to be within reach of state of the art samples. The emission can be tuned with system parameters so that the device behaves as a laser or as a N-photon gun. The theoretical formalism to characterize such emitters is developed, with the bundle statistics arising as an extension of the fundamental correlation functions of quantum optics. These emitters will be useful for quantum information processing and for medical applications. PMID:25013456

  11. Fiber bundle model under fluid pressure

    NASA Astrophysics Data System (ADS)

    Amitrano, David; Girard, Lucas

    2016-03-01

    Internal fluid pressure often plays an important role in the rupture of brittle materials. This is a major concern for many engineering applications and for natural hazards. More specifically, the mechanisms through which fluid pressure, applied at a microscale, can enhance the failure at a macroscale and accelerate damage dynamics leading to failure remains unclear. Here we revisit the fiber bundle model by accounting for the effect of fluid under pressure that contributes to the global load supported by the fiber bundle. Fluid pressure is applied on the broken fibers, following Biot's theory. The statistical properties of damage avalanches and their evolution toward macrofailure are analyzed for a wide range of fluid pressures. The macroscopic strength of the new model appears to be strongly controlled by the action of the fluid, particularly when the fluid pressure becomes comparable with the fiber strength. The behavior remains consistent with continuous transition, i.e., second order, including for large pressure. The main change concerns the damage acceleration toward the failure that is well modeled by the concept of sweeping of an instability. When pressure is increased, the exponent β characterizing the power-law distribution avalanche sizes significantly decreases and the exponent γ characterizing the cutoff divergence when failure is approached significantly increases. This proves that fluid pressure plays a key role in failure process acting as destabilization factor. This indicates that macrofailure occurs more readily under fluid pressure, with a behavior that becomes progressively unstable as fluid pressure increases. This may have considerable consequences on our ability to forecast failure when fluid pressure is acting.

  12. Fiber bundle model under fluid pressure.

    PubMed

    Amitrano, David; Girard, Lucas

    2016-03-01

    Internal fluid pressure often plays an important role in the rupture of brittle materials. This is a major concern for many engineering applications and for natural hazards. More specifically, the mechanisms through which fluid pressure, applied at a microscale, can enhance the failure at a macroscale and accelerate damage dynamics leading to failure remains unclear. Here we revisit the fiber bundle model by accounting for the effect of fluid under pressure that contributes to the global load supported by the fiber bundle. Fluid pressure is applied on the broken fibers, following Biot's theory. The statistical properties of damage avalanches and their evolution toward macrofailure are analyzed for a wide range of fluid pressures. The macroscopic strength of the new model appears to be strongly controlled by the action of the fluid, particularly when the fluid pressure becomes comparable with the fiber strength. The behavior remains consistent with continuous transition, i.e., second order, including for large pressure. The main change concerns the damage acceleration toward the failure that is well modeled by the concept of sweeping of an instability. When pressure is increased, the exponent β characterizing the power-law distribution avalanche sizes significantly decreases and the exponent γ characterizing the cutoff divergence when failure is approached significantly increases. This proves that fluid pressure plays a key role in failure process acting as destabilization factor. This indicates that macrofailure occurs more readily under fluid pressure, with a behavior that becomes progressively unstable as fluid pressure increases. This may have considerable consequences on our ability to forecast failure when fluid pressure is acting. PMID:27078437

  13. Historical dynamics in ecosystem service bundles

    PubMed Central

    Renard, Delphine; Rhemtulla, Jeanine M.; Bennett, Elena M.

    2015-01-01

    Managing multiple ecosystem services (ES), including addressing trade-offs between services and preventing ecological surprises, is among the most pressing areas for sustainability research. These challenges require ES research to go beyond the currently common approach of snapshot studies limited to one or two services at a single point in time. We used a spatiotemporal approach to examine changes in nine ES and their relationships from 1971 to 2006 across 131 municipalities in a mixed-use landscape in Quebec, Canada. We show how an approach that incorporates time and space can improve our understanding of ES dynamics. We found an increase in the provision of most services through time; however, provision of ES was not uniformly enhanced at all locations. Instead, each municipality specialized in providing a bundle (set of positively correlated ES) dominated by just a few services. The trajectory of bundle formation was related to changes in agricultural policy and global trends; local biophysical and socioeconomic characteristics explained the bundles’ increasing spatial clustering. Relationships between services varied through time, with some provisioning and cultural services shifting from a trade-off or no relationship in 1971 to an apparent synergistic relationship by 2006. By implementing a spatiotemporal perspective on multiple services, we provide clear evidence of the dynamic nature of ES interactions and contribute to identifying processes and drivers behind these changing relationships. Our study raises questions about using snapshots of ES provision at a single point in time to build our understanding of ES relationships in complex and dynamic social-ecological systems. PMID:26460005

  14. Characterization of bundled and individual triple-walled carbon nanotubes by resonant Raman spectroscopy.

    PubMed

    Hirschmann, Thomas Ch; Araujo, Paulo T; Muramatsu, Hiroyuki; Zhang, Xu; Nielsch, Kornelius; Kim, Yoong Ahm; Dresselhaus, Mildred S

    2013-03-26

    The optical characterization of bundled and individual triple-walled carbon nanotubes was studied for the first time in detail by using resonant Raman spectroscopy. In our approach, the outer tube of a triple-walled carbon nanotube system protects the two inner tubes (or equivalently the inner double-walled carbon nanotube) from external environment interactions making them a partially isolated system. Following the spectral changes and line-widths of the radial breathing modes and G-band by performing laser energy dependent Raman spectroscopy, it is possible to extract important information as regards to the electronic and vibrational properties, tube diameters, wall-to-wall distances, radial breathing mode, and G-band resonance evolutions as well as high-curvature intertube interactions in isolated double- and triple-walled carbon nanotube systems. PMID:23311296

  15. His bundle recordings in right bundle-branch block coexisting with iatrogenic right ventricular pre-excitation

    PubMed Central

    Castellanos, Agustin; Castillo, Cesar A.

    1972-01-01

    Iatrogenic right ventricular pre-excitation failed to abolish right bundle-branch block in two patients. When `exclusive' His bundle pacing was performed, the QRS complexes, St-V, and St-LVE intervals were similar to the ventricular deflections, H-V, and V-LVE (intervals) recorded during sinus rhythm. `Exclusive' pacing of the ordinary muscle at the right ventricular inflow tract produced a complete left bundle-branch block pattern without abnormal left axis deviation. Pacing of both His bundle and ordinary muscle yielded combination complexes in which the right bundle-branch block pattern persisted. The ventricular activation process was studied in these beats, as well as during the right and left bundle-branch block induced by coupled atrial stimulation. It appeared as if certain areas of the right septal surface behaved, electrophysiologically, as if they belonged to the left ventricle. Impulses emerging from these sites were not propagated to the right ventricular free wall. The latter was activated by the excitation front emerging through the left bundle system. During right bundle-branch block the endocardium of the right ventricular inflow was activated before the peak of the R in V1. Bipolar leads, 1 mm apart (with the possible exception of the ones over the tricuspid valve), were helpful in mapping the spread of activation in the human heart. Images PMID:18610233

  16. The TALE class homeobox gene Smed-prep defines the anterior compartment for head regeneration.

    PubMed

    Felix, Daniel A; Aboobaker, A Aziz

    2010-04-01

    Planaria continue to blossom as a model system for understanding all aspects of regeneration. They provide an opportunity to understand how the replacement of missing tissues from preexisting adult tissue is orchestrated at the molecular level. When amputated along any plane, planaria are capable of regenerating all missing tissue and rescaling all structures to the new size of the animal. Recently, rapid progress has been made in understanding the developmental pathways that control planarian regeneration. In particular Wnt/beta-catenin signaling is central in promoting posterior fates and inhibiting anterior identity. Currently the mechanisms that actively promote anterior identity remain unknown. Here, Smed-prep, encoding a TALE class homeodomain, is described as the first gene necessary for correct anterior fate and patterning during planarian regeneration. Smed-prep is expressed at high levels in the anterior portion of whole animals, and Smed-prep(RNAi) leads to loss of the whole brain during anterior regeneration, but not during lateral regeneration or homeostasis in intact worms. Expression of markers of different anterior fated cells are greatly reduced or lost in Smed-prep(RNAi) animals. We find that the ectopic anterior structures induced by abrogation of Wnt signaling also require Smed-prep to form. We use double knockdown experiments with the S. mediterranea ortholog of nou-darake (that when knocked down induces ectopic brain formation) to show that Smed-prep defines an anterior fated compartment within which stem cells are permitted to assume brain fate, but is not required directly for this differentiation process. Smed-prep is the first gene clearly implicated as being necessary for promoting anterior fate and the first homeobox gene implicated in establishing positional identity during regeneration. Together our results suggest that Smed-prep is required in stem cell progeny as they form the anterior regenerative blastema and is required for

  17. Combining classical and molecular approaches elaborates on the complexity of mechanisms underpinning anterior regeneration.

    PubMed

    Evans, Deborah J; Owlarn, Suthira; Tejada Romero, Belen; Chen, Chen; Aboobaker, A Aziz

    2011-01-01

    The current model of planarian anterior regeneration evokes the establishment of low levels of Wnt signalling at anterior wounds, promoting anterior polarity and subsequent elaboration of anterior fate through the action of the TALE class homeodomain PREP. The classical observation that decapitations positioned anteriorly will regenerate heads more rapidly than posteriorly positioned decapitations was among the first to lead to the proposal of gradients along an anteroposterior (AP) axis in a developmental context. An explicit understanding of this phenomenon is not included in the current model of anterior regeneration. This raises the question what the underlying molecular and cellular basis of this temporal gradient is, whether it can be explained by current models and whether understanding the gradient will shed light on regenerative events. Differences in anterior regeneration rate are established very early after amputation and this gradient is dependent on the activity of Hedgehog (Hh) signalling. Animals induced to produce two tails by either Smed-APC-1(RNAi) or Smed-ptc(RNAi) lose anterior fate but form previously described ectopic anterior brain structures. Later these animals form peri-pharyngeal brain structures, which in Smed-ptc(RNAi) grow out of the body establishing a new A/P axis. Combining double amputation and hydroxyurea treatment with RNAi experiments indicates that early ectopic brain structures are formed by uncommitted stem cells that have progressed through S-phase of the cell cycle at the time of amputation. Our results elaborate on the current simplistic model of both AP axis and brain regeneration. We find evidence of a gradient of hedgehog signalling that promotes posterior fate and temporarily inhibits anterior regeneration. Our data supports a model for anterior brain regeneration with distinct early and later phases of regeneration. Together these insights start to delineate the interplay between discrete existing, new, and then

  18. Pseudogout: A Rare Cause of Acute Arthritis Following Arthroscopic Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Zaman, Mahvash; Sabir, Numaera; Charalambous, Charalambos P.

    2015-01-01

    We report a case of an acute pseudogout attack following single-bundle anterior cruciate ligament (ACL) reconstruction in a 35-year-old man. At the initial reconstruction surgery, he was found to have early degenerative changes mainly in the lateral compartment. He presented with acute onset pain and swelling following reconstruction of the ACL. Arthroscopic irrigation was performed and the synovial fluid was positive for calcium pyrophosphate crystals. A pseudogout attack must be considered in the differential diagnosis in cases of acute onset pain and swelling after arthroscopic surgery, especially with the background of degenerative knee changes, and this may signify a poorer long-term outcome. PMID:26389074

  19. Effectiveness of Hair Bundle Motility as the Cochlear Amplifier

    PubMed Central

    Sul, Bora; Iwasa, Kuni H.

    2009-01-01

    Abstract The effectiveness of hair bundle motility in mammalian and avian ears is studied by examining energy balance for a small sinusoidal displacement of the hair bundle. The condition that the energy generated by a hair bundle must be greater than energy loss due to the shear in the subtectorial gap per hair bundle leads to a limiting frequency that can be supported by hair-bundle motility. Limiting frequencies are obtained for two motile mechanisms for fast adaptation, the channel re-closure model and a model that assumes that fast adaptation is an interplay between gating of the channel and the myosin motor. The limiting frequency obtained for each of these models is an increasing function of a factor that is determined by the morphology of hair bundles and the cochlea. Primarily due to the higher density of hair cells in the avian inner ear, this factor is ∼10-fold greater for the avian ear than the mammalian ear, which has much higher auditory frequency limit. This result is consistent with a much greater significance of hair bundle motility in the avian ear than that in the mammalian ear. PMID:19917218

  20. Mechanical Amplification Exhibited by Quiescent Saccular Hair Bundles

    PubMed Central

    Roongthumskul, Yuttana; Bozovic, Dolores

    2015-01-01

    Spontaneous oscillations exhibited by free-standing hair bundles from the Bullfrog sacculus suggest the existence of an active process that might underlie the exquisite sensitivity of the sacculus to mechanical stimulation. However, this spontaneous activity is suppressed by coupling to an overlying membrane, which applies a large mechanical load on the bundle. How a quiescent hair bundle utilizes its active process is still unknown. We studied the dynamics of motion of individual hair bundles under different offsets in the bundle position, and observed the occurrence of spikes in hair-bundle motion, associated with the generation of active work. These mechanical spikes can be evoked by a sinusoidal stimulus, leading to an amplified movement of the bundle with respect to the passive response. Amplitude gain reached as high as 100-fold at small stimulus amplitudes. Amplification of motion decreased with increasing amplitude of stimulation, ceasing at ∼6–12 pN stimuli. Results from numerical simulations suggest that the adaptation process, mediated by myosin 1c, is not required for the production of mechanical spikes. PMID:25564852

  1. Spontaneous Oscillation by Hair Bundles of the Bullfrog's Sacculus

    PubMed Central

    Martin, Pascal; Bozovic, D.; Choe, Y.; Hudspeth, A. J.

    2007-01-01

    One prominent manifestation of mechanical activity in hair cells is spontaneous otoacoustic emission, the unprovoked emanation of sound by an internal ear. Because active hair-bundle motility probably constitutes the active process of non-mammalian hair cells, we investigated the ability of hair bundles in the bullfrog's sacculus to produce oscillations that might underlie spontaneous otoacoustic emissions. When maintained in the ear's normal ionic milieu, many bundles oscillated spontaneously through distances as great as 80 nm at frequencies of 5-50 Hz. Whole-cell recording disclosed that the positive phase of movement was associated with the opening of transduction channels. Gentamicin, which blocks transduction channels, reversibly arrested oscillation; drugs that affect the cAMP phosphorylation pathway and might influence myosin's activity altered the rate of oscillation. Increasing the Ca2+ concentration rendered oscillations faster and smaller until they were suppressed; lowering the Ca2+ concentration moderately with chelators had the opposite effect. When a bundle was offset with a stimulus fiber, oscillations were transiently suppressed but gradually resumed. Loading a bundle by partial displacement clamping, which simulated the presence of the accessory structures to which a bundle is ordinarily attached, increased the frequency and diminished the magnitude of oscillation. These observations accord with a model in which oscillations arise from the interplay of the hair bundle's negative stiffness with the activity of adaptation motors and with Ca2+-dependent relaxation of gating springs. PMID:12805294

  2. Mechanical amplification exhibited by quiescent saccular hair bundles.

    PubMed

    Roongthumskul, Yuttana; Bozovic, Dolores

    2015-01-01

    Spontaneous oscillations exhibited by free-standing hair bundles from the Bullfrog sacculus suggest the existence of an active process that might underlie the exquisite sensitivity of the sacculus to mechanical stimulation. However, this spontaneous activity is suppressed by coupling to an overlying membrane, which applies a large mechanical load on the bundle. How a quiescent hair bundle utilizes its active process is still unknown. We studied the dynamics of motion of individual hair bundles under different offsets in the bundle position, and observed the occurrence of spikes in hair-bundle motion, associated with the generation of active work. These mechanical spikes can be evoked by a sinusoidal stimulus, leading to an amplified movement of the bundle with respect to the passive response. Amplitude gain reached as high as 100-fold at small stimulus amplitudes. Amplification of motion decreased with increasing amplitude of stimulation, ceasing at ∼6-12 pN stimuli. Results from numerical simulations suggest that the adaptation process, mediated by myosin 1c, is not required for the production of mechanical spikes. PMID:25564852

  3. Spontaneous oscillation by hair bundles of the bullfrog's sacculus.

    PubMed

    Martin, Pascal; Bozovic, D; Choe, Y; Hudspeth, A J

    2003-06-01

    One prominent manifestation of mechanical activity in hair cells is spontaneous otoacoustic emission, the unprovoked emanation of sound by an internal ear. Because active hair bundle motility probably constitutes the active process of nonmammalian hair cells, we investigated the ability of hair bundles in the bullfrog's sacculus to produce oscillations that might underlie spontaneous otoacoustic emissions. When maintained in the normal ionic milieu of the ear, many bundles oscillated spontaneously through distances as great as 80 nm at frequencies of 5-50 Hz. Whole-cell recording disclosed that the positive phase of movement was associated with the opening of transduction channels. Gentamicin, which blocks transduction channels, reversibly arrested oscillation; drugs that affect the cAMP phosphorylation pathway and might influence the activity of myosin altered the rate of oscillation. Increasing the Ca 2+ concentration rendered oscillations faster and smaller until they were suppressed; lowering the Ca 2+ concentration moderately with chelators had the opposite effect. When a bundle was offset with a stimulus fiber, oscillations were transiently suppressed but gradually resumed. Loading a bundle by partial displacement clamping, which simulated the presence of the accessory structures to which a bundle is ordinarily attached, increased the frequency and diminished the magnitude of oscillation. These observations accord with a model in which oscillations arise from the interplay of the hair bundle's negative stiffness with the activity of adaptation motors and with Ca 2+-dependent relaxation of gating springs. PMID:12805294

  4. Equivariant algebraic vector bundles over representations of reductive groups: theory.

    PubMed Central

    Masuda, M; Petrie, T

    1991-01-01

    Let G be a reductive algebraic group and let B be an affine variety with an algebraic action of G. Everything is defined over the field C of complex numbers. Consider the trivial G-vector bundle B x S = S over B where S is a G-module. From the endomorphism ring R of the G-vector bundle S a construction of G-vector bundles over B is given. The bundles constructed this way have the property that when added to S they are isomorphic to F + S for a fixed G-module F. For such a bundle E an invariant rho(E) is defined that lies in a quotient of R. This invariant allows us to distinguish nonisomorphic G-vector bundles. This is applied to the case where B is a G-module and, in that case, an invariant of the underlying equivariant variety is given too. These constructions and invariants are used to produce families of inequivalent G-vector bundles over G-modules and families of inequivalent G actions on affine spaces for some finite and some connected semisimple groups. PMID:11607220

  5. Stochastic Molecular Transport on Microtubule Bundles with Structural Defects

    NASA Astrophysics Data System (ADS)

    Gramlich, M. W.; Tabei, S. M. Ali

    Intracellular transport involves complex coordination of multiple components such as: the cytoskeletal network and molecular motors. Perturbations in this process can amplify over time and space, thereby affecting transport. One little studied component of transport are structural defects in the cytoskeletal network. In this talk we will present a stochastic model of the interaction of the molecular motor, kinesin-1, and a bundled cystoskeletal network of microtubules, and explicitly explore the role of microtubule ends (a type of defect) on long-range transport. We will show how different types of end distributions can ultimately result in the same observed transport behavior for bundles. We compare transport on completely uniform bundles, found in the axon, to completely random bundles, found in dendrites. Because of the un-biased random bundle nature, defects affect transport on dendrite bundles more than on uniform bundles in the axon. Further, defects act as large spatial-scale traps that result in random wait-times which have been assumed in previous models.

  6. Measurement of depletion-induced force in microtubule bundles

    NASA Astrophysics Data System (ADS)

    Hilitski, Fiodar; Ward, Andrew; Dogic, Zvonimir

    2014-03-01

    Microtubule (MT) bundles formed in the presence of non-adsorbing polymers - poly-ethylene glycol (PEG) or Dextran - are widely used in experimental active matter systems. However, many properties of such MT bundles have not been studied experimentally. In this work, we combine optical trapping techniques with an umbrella sampling method in order to measure the depletion force acting on individual microtubule in the axial direction within the bundle. We find depletion force is independent of bundle overlap length and measure its magnitude to be on the order of tens of kB/T μm. We explore the dependence of the depletion force on concentration of depletant (PEG 20K) as well as K+ ions (necessary for screening electrostatic repulsion between MT filaments). We also verify additivity of depletion interaction and confirm that force is increased by a factor of two for three-MT bundles. Additionally, our experimental technique allows us to probe interactions between MTs within the bundle. Experimental data suggests that filaments in the bundle interact only hydrodynamically when depletant concentrations are low enough; however, we observe onset of solid-like friction when osmotic pressure is increased above a certain threshold.

  7. Steric Effects Induce Geometric Remodeling of Actin Bundles in Filopodia.

    PubMed

    Dobramysl, Ulrich; Papoian, Garegin A; Erban, Radek

    2016-05-10

    Filopodia are ubiquitous fingerlike protrusions, spawned by many eukaryotic cells, to probe and interact with their environments. Polymerization dynamics of actin filaments, comprising the structural core of filopodia, largely determine their instantaneous lengths and overall lifetimes. The polymerization reactions at the filopodial tip require transport of G-actin, which enter the filopodial tube from the filopodial base and diffuse toward the filament barbed ends near the tip. Actin filaments are mechanically coupled into a tight bundle by cross-linker proteins. Interestingly, many of these proteins are relatively short, restricting the free diffusion of cytosolic G-actin throughout the bundle and, in particular, its penetration into the bundle core. To investigate the effect of steric restrictions on G-actin diffusion by the porous structure of filopodial actin filament bundle, we used a particle-based stochastic simulation approach. We discovered that excluded volume interactions result in partial and then full collapse of central filaments in the bundle, leading to a hollowed-out structure. The latter may further collapse radially due to the activity of cross-linking proteins, hence producing conical-shaped filament bundles. Interestingly, electron microscopy experiments on mature filopodia indeed frequently reveal actin bundles that are narrow at the tip and wider at the base. Overall, our work demonstrates that excluded volume effects in the context of reaction-diffusion processes in porous networks may lead to unexpected geometric growth patterns and complicated, history-dependent dynamics of intermediate metastable configurations. PMID:27166814

  8. Bundling actin filaments from membranes: some novel players

    PubMed Central

    Thomas, Clément

    2012-01-01

    Progress in live-cell imaging of the cytoskeleton has significantly extended our knowledge about the organization and dynamics of actin filaments near the plasma membrane of plant cells. Noticeably, two populations of filamentous structures can be distinguished. On the one hand, fine actin filaments which exhibit an extremely dynamic behavior basically characterized by fast polymerization and prolific severing events, a process referred to as actin stochastic dynamics. On the other hand, thick actin bundles which are composed of several filaments and which are comparatively more stable although they constantly remodel as well. There is evidence that the actin cytoskeleton plays critical roles in trafficking and signaling at both the cell cortex and organelle periphery but the exact contribution of actin bundles remains unclear. A common view is that actin bundles provide the long-distance tracks used by myosin motors to deliver their cargo to growing regions and accordingly play a particularly important role in cell polarization. However, several studies support that actin bundles are more than simple passive highways and display multiple and dynamic roles in the regulation of many processes, such as cell elongation, polar auxin transport, stomatal and chloroplast movement, and defense against pathogens. The list of identified plant actin-bundling proteins is ever expanding, supporting that plant cells shape structurally and functionally different actin bundles. Here I review the most recently characterized actin-bundling proteins, with a particular focus on those potentially relevant to membrane trafficking and/or signaling. PMID:22936939

  9. The double massa intermedia

    PubMed Central

    Baydin, Serhat; Gungor, Abuzer; Baran, Oguz; Tanriover, Necmettin; Rhoton, Albert L.

    2016-01-01

    Background: To describe the rare finding of a double massa intermedia (MI). Typically, the MI (interthalamic adhesion) is a single bridge of gray matter connecting the medial surfaces of the thalami. Methods: Twelve formalin- and alcohol-fixed human third ventricles were examined from superior to inferior by fiber dissection technique under ×6 to ×40 magnifications and with the endoscope. Results: In all hemispheres, the anterior and posterior commissure were defined. The MI, which bridges the medial surfaces of the thalami, was defined in all hemispheres. In one hemisphere, there was a second bridge between the thalami, located posteroinferior to the common MI. Endoscopic view confirmed that there was a second MI in this specimen. The MI usually traverses the third ventricle posterior to the foramen of Monro and connects the paired thalami. The MI is an important landmark during endoscopic and microscopic surgeries of the third ventricle. Although a double MI is very rare, surgeons should be aware of the possibility in their surgical planning. Conclusion: The surgeon should be aware of the possibility of a double MI to avoid confusion during third ventricle surgery. PMID:27127695

  10. Anterior spinal cord syndrome of unknown etiology

    PubMed Central

    Klakeel, Merrine; Thompson, Justin; McDonald, Frank

    2015-01-01

    A spinal cord injury encompasses a physical insult to the spinal cord. In the case of anterior spinal cord syndrome, the insult is a vascular lesion at the anterior spinal artery. We present the cases of two 13-year-old boys with anterior spinal cord syndrome, along with a review of the anatomy and vasculature of the spinal cord and an explanation of how a lesion in the cord corresponds to anterior spinal cord syndrome. PMID:25552812