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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. Individualized anterior cruciate ligament surgery: a prospective study comparing anatomic single- and double-bundle reconstruction.

    PubMed

    Hussein, Mohsen; van Eck, Carola F; Cretnik, Andrej; Dinevski, Dejan; Fu, Freddie H

    2012-08-01

    Reconstruction of the anterior cruciate ligament (ACL) has become a commonly performed procedure. However, biomechanical studies have demonstrated that conventional single-bundle ACL reconstruction techniques are only successful in limiting anterior tibial translation but less effective for restoring rotatory laxity. This study aimed to compare the results of single- and double-bundle ACL reconstruction using an anatomic technique, individualized based on the patient's native ACL size. The authors hypothesized that there would be no difference between the results of anatomic single-bundle (ASB) and anatomic double-bundle (ADB) reconstruction when the surgical technique is individualized. Cohort study; Level of evidence, 2. Depending on intraoperative measurements of the ACL insertion site size, patients were selected for either ASB (n = 32) or ADB (n = 69) ACL reconstruction. In all groups, hamstring tendons autograft was used with suspensory fixation on the femoral side and bioabsorbable interference screw fixation on the tibial side. The outcomes were evaluated by an independent blinded observer using the Lysholm score, subjective International Knee Documentation Committee (IKDC) form, KT-1000 arthrometer for anteroposterior stability, and pivot-shift test for rotational stability. The average follow-up was 30 months (range, 26-34 months). There were no statistically significant differences in the baseline demographics of the 2 groups. There was no significant difference between the ADB and ASB groups for Lysholm score (93.9 vs 93.5), subjective IKDC score (93.3 vs 93.1), anterior tibial translation (1.5- vs 1.6-mm side-to-side difference), and pivot shift (92% vs 90% with negative pivot-shift examination). Anatomic double-bundle reconstruction is not superior to anatomic single-bundle reconstruction when an individualized ACL reconstruction technique is used.

  3. Anatomic and nonanatomic double-bundle anterior cruciate ligament reconstruction: an in vivo kinematic analysis.

    PubMed

    Zaffagnini, Stefano; Marcheggiani Muccioli, Giulio Maria; Signorelli, Cecilia; Lopomo, Nicola; Grassi, Alberto; Bonanzinga, Tommaso; Nitri, Marco; Marcacci, Maurilio

    2014-03-01

    There have been no direct in vivo biomechanical comparisons performed between an anatomic double-bundle (ADB) and a nonanatomic double-bundle (NADB) anterior cruciate ligament (ACL) reconstruction. There are differences in kinematic outcomes between ADB and NADB ACL reconstruction techniques. Controlled laboratory study. Twenty-six consecutive patients (mean age, 30 years; range, 18-32 years; 23 men, 3 women; 17 right knees, 9 left knees) with an isolated ACL injury were included in the study. The first 13 consecutive patients underwent NADB reconstruction (combination of a single-bundle and an over-the-top reconstruction), and the following 13 consecutive patients were treated with an ADB approach (using 2 tibial tunnels and 2 femoral tunnels placed in the center of the native femoral and tibial insertion sites). Grafts were pretensioned at 80 N and secured with cortical fixation systems under manual maximum force tension. Standard clinical laxity and pivot-shift tests were quantified at time zero before and after ACL reconstruction by means of a surgical navigation system dedicated to kinematic assessment; displacement of the medial and lateral compartments during the tests was also analyzed. The ADB-reconstructed knees showed a larger preoperative-to-postoperative difference in anterior-posterior tibial plateau displacement of the medial and lateral compartments when compared with the NADB-reconstructed knees during the internal-external rotation test at 30° of flexion (P < .050). No other significant differences in laxity or pivot-shift values were noted. The mean surgical time for ADB reconstruction was significantly higher than that for NABD reconstruction (62 ± 13 and 43 ± 10 minutes, respectively; P < .0001). Results showed a greater anterior-posterior translation of both compartments during the rotational passive laxity test in the ADB reconstruction group or overconstraint caused by the NADB technique. The 2 analyzed double-bundle ACL reconstructions

  4. Outcome of double bundle anterior cruciate ligament reconstruction using crosspin and aperture fixation

    PubMed Central

    Joshi, Deepak; Jain, Vineet; Goyal, Ankit; Bahl, Vibhu; Modi, Prashant; Chaudhary, Deepak

    2014-01-01

    Background: Double bundle anterior cruciate ligament (DBACL) reconstruction is said to reproduce the native anterior cruciate ligament (ACL) anatomy better than single bundle anterior cruciate ligament, whether it leads to better functional results is debatable. Different fixation methods have been used for DBACL reconstruction, the most common being aperture fixation on tibial side and cortical suspensory fixation on the femoral side. We present the results of DBACL reconstruction technique, wherein on the femoral side anteromedial (AM) bundle is fixed with a crosspin and aperture fixation was done for the posterolateral (PL) bundle. Materials and Methods: Out of 157 isolated ACL injury patients who underwent ACL reconstruction, 100 were included in the prospective study. Arthroscopic DBACL reconstruction was done using ipsilateral hamstring autograft. AM bundle was fixed using Transfix (Arthrex, Naples, FL, USA) on the femoral side and bio interference screw (Arthrex, Naples, FL, USA) on the tibial side. PL bundle was fixed on femoral as well as on tibial side with a biointerference screw. Patients were evaluated using KT-1000 arthrometer, Lysholm score, International Knee Documentation Committee (IKDC) Score and isokinetic muscle strength testing. Methods: Out of 157 isolated ACL injury patients who underwent ACL reconstruction, 100 were included in the prospective study. Arthroscopic DBACL reconstruction was done using ipsilateral hamstring autograft. AM bundle was fixed using Transfix (Arthrex, Naples, FL, USA) on the femoral side and bio interference screw (Arthrex, Naples, FL, USA) on the tibial side. PL bundle was fixed on femoral as well as on tibial side with a biointerference screw. Patients were evaluated using KT-1000 arthrometer, Lysholm score, International Knee Documentation Committee (IKDC) Score and isokinetic muscle strength testing. Results: The KT-1000 results were evaluated using paired t test with the P value set at 0.001. At the end of 1

  5. Correlation between Femoral Guidewire Position and Tunnel Communication in Double Bundle Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Lee, Sang Hyuk; Choi, Jun Young; Kim, Dong Hee; Kang, Bun Jung; Nam, Dae Cheol; Yoon, Hong Kwon

    2014-01-01

    Purpose The object of this study was to determine the shortest possible distances of antero-medial (AM) and postero-lateral (PL) guide wire tunnel positions required to prevent femoral bone tunnel communication in double-bundle anterior cruciate ligament (ACL) reconstruction using human cadaver knees. Materials and Methods The centers of femoral AM and PL bundles of 16 cadaveric knees were drilled with guide wires and the distances of guide wires, were measured upon entrance into the bone. Femoral tunnel drilling was performed using transportal technique. The diameters of AM and PL graft were 8 mm and 6 mm, respectively. CT scans were taken on each knee, and 3-dimensional models were constructed to identify the femoral tunnel position and to create AM and PL tunnel virtual cylinders. Thickness of the bone bridge between the two tunnels was measured. Results In four out of six specimens, in which the guide wires were placed at less than or equal to 9 mm, communication was noted. In specimens with guide wires placed at distances greater than or equal to 10 mm, communication was not noted. The two groups showed a statistically significant difference (p=0.008). In cases where the distance between the AM and PL femoral tunnel guide wires was 12 mm, the bone bridge thickness was greater than 2 mm along the tunnel. Conclusion The technique for double bundle-anterior cruciate ligament (DB-ACL) reconstruction that we show here can avoid bone tunnel communication when AM and PL femoral guide wires are placed at least 10 mm apart, and 12 mm should be kept to preserve 2 mm bone bridge thickness. PMID:25323896

  6. Posterior lateral meniscal root tear due to a malpositioned double-bundle anterior cruciate ligament reconstruction tibial tunnel.

    PubMed

    LaPrade, Christopher M; Jisa, Kyle A; Cram, Tyler R; LaPrade, Robert F

    2015-12-01

    The posterior lateral (PL) meniscal root plays an essential role in ensuring the health of the articular cartilage of the knee joint. Injuring the PL meniscal root has been demonstrated to result in significant deleterious changes to tibiofemoral contact mechanics. Anatomic studies have reported that the posterolateral bundle of the anterior cruciate ligament (ACL) and PL root lie in close proximity on the tibial plateau. Therefore, during a double-bundle ACL reconstruction, the PL root may be inadvertently injured during the reaming of the posterior ACL double-bundle reconstruction tibial tunnel that is intended to recreate the posterolateral bundle of the ACL. This case report describes an occurrence of iatrogenic injury to the PL root due to a posteriorly malpositioned double-bundle ACL tibial tunnel. This report is the first known description of this mechanism of injury in the literature. Case report, Level IV.

  7. 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

  8. Effect of graft fixation sequence on knee joint biomechanics in double-bundle anterior cruciate ligament reconstruction.

    PubMed

    Shi, Dongliang; Zhou, Jingbin; Yapici, Can; Linde-Rosen, Monica; Smolinski, Patrick; Fu, Freddie H

    2015-03-01

    To investigate the effect of graft fixation sequence in double-bundle anterior cruciate ligament (ACL) reconstruction on knee biomechanics. Twelve mature porcine knees underwent double-bundle ACL reconstruction with a randomized fixation order of the two graft bundles. The knees were subjected to external loadings of (1) an 89 N anterior tibial load at 30°, 60° and 90° of knee flexion and (2) 4 N-m internal and external tibial torques at 30° and 60° of knee flexion for ACL intact, deficient and reconstructed states. Knee kinematics and in situ graft forces were measured under the applied loads. The anterior tibial translation of the two reconstructions was not different from each other but was significantly different from the intact ACL. There was no difference in internal and external rotations between the intact knees and the reconstructions. At lower flexion angles, the graft that was fixed last (whether anteromedial or posterolateral) tended to carry significantly higher in situ load under anterior tibial loading and tibial torques. While a difference in knee kinematics may not be observable with different graft fixation sequences, fixation sequence can alter the in situ forces that the grafts bear under knee loading.

  9. The effect of graft fixation sequence on force distribution in double-bundle anterior cruciate ligament reconstruction

    PubMed Central

    Chen, Chih-Hui; Gadikota, Hemanth R.; Gill, Thomas J.

    2011-01-01

    Purpose This paper investigated the effect of graft fixation sequence on knee joint biomechanics after a double-bundle ACL reconstruction. Method Two independently published biomechanical studies that investigated the biomechanics of double-bundle ACL reconstructions using similar robotic testing systems were compared. In each study, ten human cadaveric knees were tested under three different conditions: intact, ACL deficient, and ACL reconstructed using a double-bundle technique with the anteromedial (AM) graft fixed at 60° of flexion and the posterolateral (PL) graft fixed at full extension. In one study (Study A), the AM graft was fixed first; while in another study (Study B), the PL graft was fixed first. Knee kinematics, in situ forces of the ACL and the ACL grafts were measured under two loading conditions: an anterior tibial load of 134 N and a combined tibial torques (10 N·m valgus and 5 N·m internal tibial torques) in both studies. Result When AM graft was fixed first, the in situ force of the AM graft was lower than the native AM bundle at all flexion angles. The in situ force in the PL graft, however, was higher than the native PL bundle at all flexion angles. When the PL graft was fixed first, the in situ force of the AM graft was higher than the native AM bundle, while the in situ forces of the PL graft were lower than the native PL bundle at all flexion angles. Both studies demonstrated that the double-bundle ACL reconstructions can closely restore the normal knee joint kinematics. Conclusion Even though the grafts were fixed using similar initial tensions and at same flexion angles, the sequence of fixing the two grafts in a double-bundle ACL reconstruction could alter the in situ forces in the grafts and affect the knee kinematics. These data imply that in clinical application of a double-bundle ACL reconstruction, the sequence of graft fixation should be an important surgical parameter. PMID:21082163

  10. Effects of Remnant Tissue Preservation on Clinical and Arthroscopic Results After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction.

    PubMed

    Kondo, Eiji; Yasuda, Kazunori; Onodera, Jun; Kawaguchi, Yasuyuki; Kitamura, Nobuto

    2015-08-01

    Clinical utility of remnant tissue preservation after single-bundle anterior cruciate ligament (ACL) reconstruction has not been established. In addition, no studies have evaluated the clinical utility of remnant preservation after anatomic double-bundle ACL reconstruction. The study hypotheses were as follows: (1) Subjective and functional clinical results may be comparable between anatomic double-bundle reconstructions that preserve the remnant tissue and those that resect the remnant tissue, (2) postoperative knee stability and the second-look arthroscopic evaluation may be significantly more favorable with the remnant-preserving reconstruction, and (3) the degree of the initial graft coverage may significantly affect postoperative knee stability. Cohort study; Level of evidence, 2. A total of 179 patients underwent anatomic double-bundle ACL reconstruction. Based on the Crain classification of ACL remnant tissue, 81 patients underwent the remnant-preserving procedure (group P) and the remaining 98 patients underwent the remnant-resecting procedure (group R). There were no differences between the 2 groups concerning all background factors, including preoperative knee instability and intraoperative tunnel positions. The patients were followed for 2 years or more. The subjective and functional clinical results were comparable between the 2 reconstruction procedures. Side-to-side anterior laxity was significantly less (P = .0277) in group P (0.9 mm) than in group R (1.5 mm). The pivot-shift test was negative in 89% of group P and 78% of group R patients; the result for group R was significantly lower (P = .0460). In the arthroscopic observations, results for group P were significantly better than for group R concerning postoperative laceration and fibrous tissue coverage of the grafts (P = .0479). Remnant preservation in anatomic double-bundle ACL reconstruction did not significantly improve subjective and functional results in the short-term evaluation, but it

  11. Clinical Results of Technique for Double Bundle Anterior Cruciate Ligament Reconstruction Using Hybrid Femoral Fixation and Retroscrew

    PubMed Central

    Kim, Doo-Sup; Yi, Chang-Ho; Chung, Hoi-Jung

    2011-01-01

    Background Anatomic anterior cruciate ligament (ACL) reconstruction has been presented as a means to more accurately restore the native anatomy of this ligament. This article describes a new method that uses a double bundle to perform ACL reconstruction and to evaluate the clinical outcome. Methods Grafts are tibialis anterior tendon allograft for anteromedial bundle (AMB) and hamstring tendon autograft without detachment of the tibial insertion for posterolateral bundle (PLB). This technique creates 2 tunnels in both the femur and tibia. Femoral fixation was done by hybrid fixation using Endobutton and Rigidfix for AMB and by biointerference screw for PLB. Tibial fixations are done by Retroscrew for AMB and by native insertion of hamstring tendon for PLB. Both bundles are independently and differently tensioned. We performed ACL reconstruction in 63 patients using our new technique. Among them, 47 participated in this study. The patients were followed up with clinical examination, Lysholm scales and International Knee Documentation Committee (IKDC) scoring system and radiological examination with a minimum 12 month follow-up duration. Results Significant improvement was seen on Lachman test and pivot-shift test between preoperative and last follow-up. Only one of participants had flexion contracture about 5 degrees at last follow-up. In anterior drawer test by KT-1000, authors found improvement from average 8.3 mm (range, 4 to 18 mm) preoperatively to average 1.4 mm (range, 0 to 6 mm) at last follow-up. Average Lysholm score of all patients was 72.7 ± 8.8 (range, 54 to 79) preoperatively and significant improvement was seen, score was 92.2 ± 5.3 (range, 74 to 97; p < 0.05) at last follow-up. Also IKDC score was normal in 35 cases, near normal in 11 cases, abnormal in 1 case at last follow-up. Conclusions Our new double bundle ACL reconstruction technique used hybrid fixation and Retroscrew had favorable outcomes. PMID:22162791

  12. Anterior knee symptoms after double-bundle ACL reconstruction with hamstring tendon autografts: an ultrasonographic and power Doppler investigation.

    PubMed

    Kanamoto, Takashi; Tanaka, Yoshinari; Yonetani, Yasukazu; Kita, Keisuke; Amano, Hiroshi; Kusano, Masashi; Hirabayashi, Shinji; Horibe, Shuji

    2015-11-01

    Anterior knee pain related to the donor site is a frequent complication of anterior cruciate ligament reconstruction (ACLR) with bone-patellar tendon-bone autograft tissue. Even when hamstring tendon (HT) grafts are used instead, symptoms such as mild pain and discomfort can still occur. The purpose of this study was to elucidate the pathophysiology of anterior knee symptoms after ACLR with HT autografts. Fifty-seven patients (22 men and 35 women; mean age, 24.7 years) who underwent anatomic double-bundle ACLR with HT autografts were examined 6 months post-operatively. The presence of anterior knee symptoms, anterior knee laxity, range of motion, and muscle strength were assessed. Changes in patellar tendon and infrapatellar fat pad (IFP) morphology and blood flow were also evaluated using ultrasound. Potential variables affecting the presence of anterior knee symptoms were subjected to univariate analysis and multivariate logistic regression analysis to identify independent risk factors. Six months post-operatively, the total incidence of anterior knee symptoms was 56.1 % (32/57). According to univariate analysis, age, quadriceps strength, and increased blood flow in the IFP were significantly associated with the presence of anterior knee symptoms. Multivariate logistic regression analysis revealed that increased blood flow in the IFP was an independent factor for the presence of anterior knee symptoms (odds ratio 5.0; 95 % confidence interval 1.3-19.9). There were no significant findings inside the patellar tendon. Increased blood flow in the IFP was identified as an independent factor for the presence of anterior knee symptoms 6 months after ACLR with HT autografts. The ultrasound evaluation can help to define precisely the origin of anterior knee symptoms after ACLR with HT autografts. Case series with no comparison groups, Level IV.

  13. Prospective randomized clinical evaluation of conventional single-bundle, anatomic single-bundle, and anatomic double-bundle anterior cruciate ligament reconstruction: 281 cases with 3- to 5-year follow-up.

    PubMed

    Hussein, Mohsen; van Eck, Carola F; Cretnik, Andrej; Dinevski, Dejan; Fu, Freddie H

    2012-03-01

    Three different techniques of anterior cruciate ligament (ACL) reconstruction--conventional (transtibial) single bundle (CSB), anatomic single bundle (ASB), and anatomic double bundle (ADB)--have been described. To determine if double-bundle reconstruction is needed to restore rotational stability or if anatomic placement of a single bundle can yield similar results. Randomized controlled trial; Level of evidence, 1. From December 2005 to December 2007, 320 patients were prospectively randomized into 3 groups: ADB, ASB, and CSB reconstruction. The average follow-up was 51.15 months (range, 39-63 months). At the final follow-up, 281 patients were available. In all groups, hamstring tendons were used with suspensory fixation on the femoral side and bioabsorbable interference screw fixation on the tibial side. The outcomes were evaluated by an independent blinded observer using the Lysholm score and subjective International Knee Documentation Committee (IKDC) form. The KT-1000 arthrometer was used to evaluate anteroposterior stability, and the pivot-shift test was used to determine rotational stability. Anatomic single-bundle reconstruction resulted in better anteroposterior and rotational stability than CSB reconstruction (average side-to-side difference for anterior tibial translation was 1.6 mm in the ASB group vs 2.0 mm in the CSB group; P = .002). Negative pivot shift was 66.7% vs 41.7% (P = .003). In other parameters, the differences between groups were not statistically significant. The results of the ADB group were also superior to the ASB group for anteroposterior and rotational stability (average side-to-side difference for anterior tibial translation was 1.2 mm in the ADB group vs 1.6 mm in the ASB group; P = .002). Negative pivot shift was 93.1% vs 66.7%, respectively (P < .001), and range of motion was also significantly different (P = .005). The Lysholm score was 90.9, 91.8, and 93.0 in the CSB, ASB, and ADB groups, respectively. The difference was

  14. 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

  15. Systemic Review of Anatomic Single- Versus Double-Bundle Anterior Cruciate Ligament Reconstruction: Does Femoral Tunnel Drilling Technique Matter?

    PubMed

    Zhang, Yang; Xu, Caiqi; Dong, Shiqui; Shen, Peng; Su, Wei; Zhao, Jinzhong

    2016-09-01

    To provide an up-to-date assessment of the difference between anatomic double-bundle anterior cruciate ligament (ACL) reconstruction (DB-ACLR) and anatomic single-bundle ACL reconstruction (SB-ACLR). We hypothesized that anatomic SB-ACLR using independent femoral drilling technique would be able to achieve kinematic stability as with anatomic DB-ACLR. A comprehensive Internet search was performed to identify all therapeutic trials of anatomic DB-ACLR versus anatomic SB-ACLR. Only clinical studies of Level I and II evidence were included. The comparative outcomes were instrument-measured anterior laxity, Lachman test, pivot shift, clinical outcomes including objective/subjective International Knee Documentation Committee (IKDC) score, Lysholm score, Tegner activity scale and complication rates of extension/flexion deficits, graft failure, and early osteoarthritis. Subgroup analyses were performed for femoral tunnel drilling techniques including independent drilling and transtibial (TT) drilling. Twenty-two clinical trials of 2,261 anatomically ACL-reconstructed patients were included in the meta-analysis. Via TT drilling technique, anatomic DB-ACLR led to improved instrument-measured anterior laxity with a standard mean difference (SMD) of -0.42 (95% confidence interval [CI] = -0.81 to -0.02), less rotational instability measured by pivot shift (SMD = 2.76, 95% CI = 1.24 to 6.16), and higher objective IKDC score with odds ratio (OR) of 2.28 (95% CI = 1.19 to 4.36). Via independent drilling technique, anatomic DB-ACLR yielded better pivot shift (SMD = 2.04, 95% CI = 1.36 to 3.05). Anatomic DB-ACLR also revealed statistical significance in subjective IKDC score compared with anatomic SB-ACLR (SMD = 0.27, 95% CI = 0.05 to 0.49). Anatomic DB-ACLR showed better anterior and rotational stability and higher objective IKDC score than anatomic SB-ACLR via TT drilling technique. Via independent drilling technique, however, anatomic DB-ACLR only showed superiority

  16. Anatomical "C"-shaped double-bundle versus single-bundle anterior cruciate ligament reconstruction in pre-adolescent children with open growth plates.

    PubMed

    Siebold, Rainer; Takada, Tsuyoshi; Feil, Sven; Dietrich, Carmen; Stinton, Shaun K; Branch, Thomas P

    2016-03-01

    To analyse the clinical, rotational and radiological (MRI) results of paediatric anatomical "C-shaped" double-bundle (DB) anterior cruciate ligament (ACL) reconstruction with anteromedial and posteromedial bundle compared to single-bundle (SB) ACL reconstruction. Between 2008 and 2014, 57 consecutive patients received a paediatric ACL reconstruction with open physis and were allocated into two groups, according to the surgical procedure. Transepiphyseal SB technique was used until 2012 and DB consecutively thereafter. Follow-up consisted of a clinical evaluation with assessment of the International Knee Documentation Committee (IKDC) form, the Lysholm knee score, Tegner activity score, KT-1000 arthrometer evaluation, VAS Scores for satisfaction, MRI and testing of rotational stability using a robotic system. The mean time from ACL reconstruction to follow-up was 48.1 ± 15.8 in the SB group (n = 17) and 23.1 ± 13.2 in the DB group (n = 16; p < 0.001). No differences were found in the subjective scores. Biomechanically, there were significant differences identified in the KT-1000 (p < 0.03) and total tibial axial rotation (p < 0.04) when evaluating the reconstructed knee only. Ten of 17 (59%) of the SB patients had a Joint Play Area within the acceptable range of the median healthy knee value compared to 100 % in the DB group. Decreased patient satisfaction was associated with increased total tibial axial rotation. No growth disturbance was observed. Overall, 98% of patients were reached and either examined or interviewed. Re-rupture rate was 3 of 21 (14.3%) for DB and 9 of 35 (25.7%) for SB. All but one re-ruptures (92%) happened in the first 16 postoperative months independent of technique. The re-rupture rate after pre-adolescent ACL reconstruction is too high both historically and in this mixed cohort. Anatomical transepiphyseal DB ACL reconstruction with open physis may result in a reduction in this re-rupture rate, which may be related to a tighter control of

  17. A quantitative technique to create a femoral tunnel at the averaged center of the anteromedial bundle attachment in anatomic double-bundle anterior cruciate ligament reconstruction

    PubMed Central

    2013-01-01

    Background In the anatomic double-bundle ACL reconstruction, 2 femoral tunnel positions are particularly critical to obtain better clinical results. Recently, a few studies have reported quantitative identification methods for posterolateral (PL) bundle reconstruction. Concerning anteromedial (AM) bundle reconstruction, however, no quantitative clinically available methods to insert a guide wire at the center of the direct attachment of the AM mid-substance fibers have been reported to date. Methods First, we determined the center of the femoral attachment of the AM mid-substance fibers using 38 fresh frozen cadaveric knees. Based on this anatomical sub-study, we developed a quantitative clinical technique to insert a guide wire at the averaged center for anatomic double-bundle ACL reconstruction. In the second clinical sub-study with 63 patients who underwent anatomic ACL reconstruction with this quantitative technique, we determined the center of an actually created AM tunnel. Then, we compared the results of the second sub-study with those of the first sub-study to validate the accuracy of the quantitative technique. In both the sub-studies, we determined the center of the anatomical attachment and the tunnel outlet using the “3-dimensional clock” system. The tunnel outlet was evaluated using the “transparent” 3-dimensional computed tomography. Results The averaged center of the direct attachment of the AM bundle midsubstance fibers was located on the cylindrical surface of the femoral intercondylar notch at “10:37” (or “1:23”) o’clock orientation in the distal view and at 5.0-mm from the proximal outlet of the intercondylar notch (POIN) in the lateral view. The AM tunnel actually created in ACL reconstruction was located at “10:41” (or “1:19”) o’clock orientation in the average and at 5.0-mm from the POIN. There was no significant difference between the 2 center locations. Conclusions The quantitative technique enabled us to easily

  18. Comparison of Knee Kinematics After Single-Bundle Anterior Cruciate Ligament Reconstruction via the Medial Portal Technique With a Central Femoral Tunnel and an Eccentric Femoral Tunnel and After Anatomic Double-Bundle Reconstruction: A Human Cadaveric Study.

    PubMed

    Herbort, Mirco; Domnick, Christoph; Raschke, Michael Johannes; Lenschow, Simon; Förster, Tim; Petersen, Wolf; Zantop, Thore

    2016-01-01

    Anatomic femoral tunnel placement in anterior cruciate ligament (ACL) reconstruction is considered to be a key to good primary stability of the knee. There is still no consensus on whether a centrally placed single bundle in the anatomical femoral footprint can compare with anatomic double-bundle (DB) reconstruction. The purpose of this study was to determine knee kinematics after single-bundle ACL reconstruction via the medial portal technique using 2 different femoral tunnel positions and to compare results with those of the anatomic DB technique. The hypotheses were that (1) single-bundle reconstruction using the medial portal technique with a centrally placed femoral tunnel relative to the native footprint (SB-central technique) would more closely restore intact knee kinematics compared with the same reconstruction technique with an eccentric femoral tunnel drilled in the anteromedial bundle footprint (SB-AM technique) and (2) DB reconstruction would result in superior kinematics compared with the SB-central technique. Controlled laboratory study. Knee kinematics was examined in 10 fresh-frozen human cadaveric knees using a robotic/universal force-moment sensor system. Kinematics in simulated pivot-shift and 134-N anterior tibial loading tests were determined in different conditions within the same specimen: (1) intact ACL, (2) deficient ACL, (3) SB-AM, (4) SB-central, and (5) DB. All reconstruction techniques significantly reduced anterior tibial translation (ATT) compared with a deficient ACL at 0°, 15°, 30°, 60°, and 90° in the anterior tibial loading test (P < .01, repeated-measures analysis of variance) and at 0°, 15°, and 30° in the simulated pivot-shift test (P < .001). There were no significant differences in the SB-central group and the DB group compared with the intact ACL. Reconstruction in the SB-AM group resulted in significantly increased ATT compared with the intact ACL in near-to-extension angles in both tests (0°, 15°, and 30°; P

  19. Single- vs. double-bundle anterior cruciate ligament reconstruction: a new aspect of knee assessment during activities involving dynamic knee rotation.

    PubMed

    Czamara, Andrzej; Królikowska, Aleksandra; Szuba, Łukasz; Widuchowski, Wojciech; Kentel, Maciej

    2015-02-01

    Few studies have compared single-bundle (SB) and double-bundle (DB) anterior cruciate ligament reconstruction (ACLR) in the knee joint during activities involving change-of-direction maneuvers and knee rotation. This study examined whether the type of ACLR contributes to postphysiotherapy outcomes, with an emphasis on knee function assessment during activities involving dynamic knee rotation. Fifteen male patients after SB ACLR and 15 male patients after DB ACLR took part in the same physiotherapy program. Twenty-four weeks after ACLR, both groups underwent anterior laxity measurement, pivot shift tests, range of movement and joint circumference measurements, subjective assessment of pain and stability levels in the knee joint, peak torque measurement of the muscles rotating the tibia toward the femur, and a run test with maximal speed and change-of-direction maneuvers. Comparative analysis did not show any differences between the results of anterior tibial translation, pivot shift test, range of movement and joint circumference, and subjective assessment of pain and knee joint stability levels. No differences were noted between the groups in peak torque values obtained from the muscles responsible for internal and external tibial rotation or results of the run test. The data obtained from this study can be used by research teams to monitor and compare the effectiveness of various study protocols involving surgical and physiotherapy treatment. The data are especially useful when combined with the clinical assessment of patients who would like to return to sport.

  20. Iliotibial band irritation caused by the EndoButton after anatomic double-bundle anterior cruciate ligament reconstruction: report of two cases.

    PubMed

    Taketomi, Shuji; Inui, Hiroshi; Hirota, Jinso; Nakamura, Kensuke; Sanada, Takaki; Masuda, Hironari; Tanaka, Sakae; Nakagawa, Takumi

    2013-08-01

    Two patients underwent arthroscopic anatomic double-bundle anterior cruciate ligament (ACL) reconstruction using the EndoButton for femoral fixation. The femoral tunnels were created by the inside-out technique through a far anteromedial portal. The patients postoperatively developed moderate lateral knee pain without instability. At the second-look arthroscopic evaluation, the two EndoButtons were removed. Both patients were completely asymptomatic several months after implant removal, implying that the EndoButtons caused the mechanical irritation in the iliotibial band. This is the first report describing removal of EndoButtons because of pain caused by friction with the iliotibial band. In anatomic ACL reconstruction, if the femoral tunnel exit is positioned near the lateral femoral epicondyle, care should be taken to prevent iliotibial band friction syndrome that could result because of the EndoButton. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Changes in the T2 relaxation value of the tibiofemoral articular cartilage about 6 months after anterior cruciate ligament reconstruction using the double-bundle technique.

    PubMed

    Gheno, Ramon; Yoon, Young Cheol; Wang, Joon H; Kim, Kyunga; Baek, Sun-Y

    2016-01-01

    To evaluate T2 relaxation values (T2RVs) of knee joint cartilage after double-bundle anterior cruciate ligament reconstruction (DB-ACLR) in a 6-month follow-up and to correlate changes between T2RVs with meniscal status and clinical findings. 27 patients who underwent DB-ACLR and MRI before and 6 months after surgery, and 27 control subjects were enrolled. We compared T2RVs of the control vs pre-operative MR and pre-operative vs post-operative MR using 28 subcompartments, including superficial and deep layers. Correlations between T2RV changes with meniscal status and clinical data were examined. The pre-operative T2RV was significantly higher than that of the control group in the medial tibia (posterior-superficial), posterior medial femur (superficial) and posterior lateral femur (superficial and deep). The post-operative T2RV was significantly higher than that of pre-operative T2RV in the posterior medial femur (superficial), medial tibia (anterior-deep and central-deep), lateral femur (anterior-deep, anterior-superficial and central-superficial) and posterior medial femur (deep). Moderate positive correlations between pre-operative and post-operative T2RV changes were found at the posterior medial femur (interval between injury and MR examination, and instability) and posterior lateral femur (Lysholm score). Patients with anterior cruciate ligament injury followed by DB-ACLR presented short-term subcompartment T2RV changes at the medial femur, lateral femur and medial tibia. Meniscal status did not affect T2RV; however, clinical findings influenced T2RV at the posterior grooves of the medial and lateral femoral condyles. Patients submitted to DB-ACLR presented T2RV changes in both femoral and medial tibial condyles 6 months after the surgery, affecting not just the weight-bearing areas, but also the less-weight-bearing areas.

  2. Bone tunnel change develops within two weeks of double-bundle anterior cruciate ligament reconstruction using hamstring autograft: A comparison of different postoperative immobilization periods using computed tomography.

    PubMed

    Shimizu, Ryo; Adachi, Nobuo; Ishifuro, Minoru; Nakamae, Atsuo; Ishikawa, Masakazu; Deie, Masataka; Ochi, Mitsuo

    2017-10-01

    The purpose of this study was to evaluate bone tunnel changes following anterior cruciate ligament (ACL) reconstruction during the early postoperative period using computed tomography (CT), and to understand the impact of postoperative immobilization on these changes. Twenty patients who underwent double-bundle ACL reconstruction using hamstring tendon autografts were included. We subcategorized patients into two groups: patients who underwent isolated ACL reconstruction and had three days of knee immobilization (Group A, n=10); and patients with concomitant meniscus injuries who underwent ACL reconstruction and meniscus repair simultaneously (Group B, n=10) had their knees immobilized for two weeks after surgery. Bone tunnel enlargement was evaluated using CT imaging at one to three days, two weeks, one month, three months and six months after surgery. The cross-sectional area of the femoral and tibial tunnels was measured, and enlargement rate was calculated. The tunnel center location at two weeks after surgery was also evaluated. The mean cross-sectional area adjacent to the joint space of the femoral and tibial tunnels significantly increased immediately after surgery, especially in the first month (P<0.01). However, after one to six months they were not increased (P>0.01). There was no significant difference in tunnel enlargement rate between group A and B. Tunnel center location changed even in the first two weeks. Bone tunnel enlargement following double-bundle ACL reconstruction occurred at an earlier time point after surgery than anticipated. Postoperative immobilization could not prevent bone tunnel enlargement, but might prevent tunnel migration. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. A new behind-remnant approach for remnant-preserving double-bundle anterior cruciate ligament reconstruction compared with a standard approach.

    PubMed

    Muneta, Takeshi; Koga, Hideyuki; Nakamura, Tomomasa; Horie, Masafumi; Watanabe, Toshifumi; Yagishita, Kazuyoshi; Sekiya, Ichiro

    2015-12-01

    To introduce a new behind-remnant approach for double-bundle (DB) anterior cruciate ligament (ACL) reconstruction and to compare the femoral tunnel positions of anteromedial (AM) and posterolateral (PL) bundles between the new and standard procedures by a three-dimensional computed tomography (3D-CT). During DB ACL reconstruction, two approaches for femoral tunnel creation were consecutively practiced from 2010 to 2012. The patients were evaluated retrospectively as a cohort study. A total of 200 primary ACL reconstructions have been performed using a transtibial approach. One approach was a standard approach from the front in which the ACL remnant was peeled off from the attachment, and two guide wires were inserted based on anatomic bony landmarks (standard group). The other approach was a new behind-remnant approach in which the ACL remnant was kept untouched and two guide wires were inserted at the posterior margin of the direct ACL insertion (behind-remnant group). The position of the AM and PL femoral tunnels was expressed on a 3D-CT reconstructive image using the quadrant method with a statistical analysis. The depth of the AM center was 24 ± 6 % (mean and standard deviation) in the standard group and 22 ± 5 % in the behind-remnant group. The height of the AM tunnel center was 22 ± 8 % in the standard group and 31 ± 8 % in the behind-remnant group. The depth of the PL tunnel center was 32 ± 6 % in the standard group and 35 ± 5 % in the behind-remnant group. The height of the PL tunnel center was 47 ± 9 % in the standard group and 55 ± 7 % in the behind-remnant group. The AM and PL femoral tunnels in both groups were created within the normal anatomic footprint of the previous studies. The behind-remnant approach created a significantly lower femoral tunnel for both AM (p = 0.000) and PL tunnels (p = 0.000). The depth of both AM and PL tunnels was not significantly different between the two groups (n.s.). The new behind-remnant procedure is

  4. Volume and contact surface area analysis of bony tunnels in single and double bundle anterior cruciate ligament reconstruction using autograft tendons: in vivo three-dimensional imaging analysis.

    PubMed

    Yang, Jae-Hyuk; Chang, Minho; Kwak, Dai-Soon; Wang, Joon Ho

    2014-09-01

    Regarding reconstruction surgery of the anterior cruciate ligament (ACL), there is still a debate whether to perform a single bundle (SB) or double bundle (DB) reconstruction. The purpose of this study was to analyze and compare the volume and surface area of femoral and tibial tunnels during transtibial SB versus transportal DB ACL reconstruction. A consecutive series of 26 patients who underwent trantibial SB ACL reconstruction and 27 patients with transportal DB ACL reconstruction using hamstring autograft from January 2010 to October 2010 were included in this study. Three-dimensional computed tomography (3D-CT) was taken within one week after operation. The CT bone images were segmented with use of Mimics software v14.0. The obtained digital images were then imported in the commercial package Geomagic Studio v10.0 and SketchUp Pro v8.0 for processing. The femoral and tibial tunnel lengths, diameters, volumes and surface areas were evaluated. A comparison between the two groups was performed using the independent-samples t-test. A p-value less than the significance value of 5% (p < 0.05) was considered statistically significant. Regarding femur tunnels, a significant difference was not found between the tunnel volume for SB technique (1,496.51 ± 396.72 mm(3)) and the total tunnel volume for DB technique (1,593.81 ± 469.42 mm(3); p = 0.366). However, the total surface area for femoral tunnels was larger in DB technique (919.65 ± 201.79 mm(2)) compared to SB technique (810.02 ± 117.98 mm(2); p = 0.004). For tibia tunnels, there was a significant difference between tunnel volume for the SB technique (2,070.43 ± 565.07 mm(3)) and the total tunnel volume for the DB technique (2,681.93 ± 668.09 mm(3); p ≤ 0.001). The tibial tunnel surface area for the SB technique (958.84 ± 147.50 mm(2)) was smaller than the total tunnel surface area for the DB technique (1,493.31 ± 220.79 mm(2); p ≤ 0.001). Although the total femoral tunnel volume was similar between two

  5. Masquerading bundle branch block: a variety of right bundle branch block with left anterior fascicular block.

    PubMed

    Elizari, Marcelo V; Baranchuk, Adrian; Chiale, Pablo A

    2013-01-01

    The so-called 'masquerading' type of right bundle branch block is caused by the simultaneous presence of a high-degree left anterior fascicular block often accompanied with severe left ventricular enlargement and/or fibrotic block in the anterolateral wall of the left ventricle. These conditions tend to reorient the terminal electrical forces of the QRS complex towards the left and upwards, in such a way that the characteristic slurred S wave in lead I becomes smaller or even disappears. In many cases of standard masquerading right bundle branch block, a small Q wave in lead I is present due to the initial forces of the left anterior fascicular block, which are oriented rightwards and inferiorly. However, in some cases, the Q wave in lead I also vanishes, and the mimicking of a left bundle branch block becomes perfect in standard leads. This is commonly associated with an inferior myocardial infarction or severe inferior fibrosis in cardiomyopathies. The typical QRS changes of right bundle branch block may eventually be concealed even in the right precordial leads; under such circumstances, the ECG diagnosis may be mistaken and the right bundle branch block totally missed. The masquerading right bundle branch block carries a poor prognosis, since it always implies the presence of a severe underlying heart disease.

  6. Ultrastructure of the three anterior cruciate ligament bundles.

    PubMed

    Suzuki, Daisuke; Otsubo, Hidenori; Watanabe, Takafumi; Kamiya, Tomoaki; Nagoya, Satoshi; Yamashita, Toshihiko; Shino, Konsei

    2015-10-01

    The anterior cruciate ligament (ACL) can be morphologically separated into not only two, but three bundles: the anteromedial-medial bundle (AM-MB), the anteromedial-lateral bundle (AM-LB), and the posterolateral bundle (PLB). Our hypothesis was that the three bundles differ in their microstructures. The purpose of this study was to clarify the microstructural differences among the three bundles. The normal ACLs of six fresh frozen cadavers were harvested. After the AM-MB, AM-LB, and PLB were identified, their fibril structures were analyzed using a transmission electron microscope. The fibril orientation, distribution pattern, and the mass average diameter of the fibrils (MAD) were compared among the AM-MBs, AM-LBs, and PLBs. The AM-MB and AM-LB fibrils were arranged mostly in the longitudinal direction, while the PLB fibrils were not aligned in a uniform direction. The fibril diameter distribution pattern of AM-MBs showed a bi-modal pattern due to the existence of small-diameter (30-40 nm) and large-diameter fibrils (70-80 nm), while that of the AM-LBs and PLBs had a unimodal pattern with one prominent high peak at a diameter of 50-60 nm. The mean MAD of the AM-MBs (83.2 - 11.2 nm) was significantly larger than that of the PLBs (66.8 - 7.7 nm), while it showed no significant difference compared to that of the AM-LBs (77.6 - 12.3 nm). The three ACL bundles have different ultrastructures. The AM-MB predominantly includes thick, uni-directionally oriented fibrils like tendons, while the PLB consists of thinner, multi-directionally oriented fibrils. The AM-LB shows an intermediate structure between the AM-MB and the PLB.

  7. [Case-control study on clinical effects of arthroscopic single-versus double-bundle ACLs reconstructions].

    PubMed

    Wang, Xiu-Feng; Yang, Guang; Xu, Tie-Feng; Liu, Tie-Min

    2012-11-01

    To compare the clinical results of arthroscopic single and double-bundle ACLs reconstructions. From January 2009 to May 2010,45 patients with anterior cruciate ligament tear were divided into two groups. In the first group,the anterior cruciate ligament were anatomical reconstructed with double-bundle semitendinous tendon, and in the second group the anterior cruciate ligaments were anatomical reconstrucated with single bundle semitendinous tendon. There were 22 patients (15 males and 7 females) in double-bundle group, with an average age of (27.04 +/- 3.68) years; 18 patients (13 males and 5 females) in single bundle group, with an average age of (28.16 +/- 4.76) years. Therapeutic effects between two groups were compared according to the IKDC, Lysholm scoring standards and Lachman test, knee pivot shift test, KT-1000. Twenty-two patients in double-bundle group and 18 patients in single-bundle group were followed-up, and the mean duration was 12 months. The IKDC score of patients in single-bundle group improved from preoperative 41.40 +/- 6.30 to postoperatively 95.70 +/- 3.10, Lysholm score increased from preoperative 47.20 +/- 6.30 to postoperative 94.20 +/- 2.40. And the IKDC score of patients in double-bundle group improved from preoperative 40.90 +/- 6.10 to postoperative 96.10 +/-3.40, Lysholm score increased from preoperative 48.10 +/- 6.50 to postoperative 95.10 +/- 2.49. There was no statistically significant difference between the two groups. The Lachman test was positive in 2 patients (1 patient in double-bundle group and 1 patient in single-bundle group); and pivot shift test was positive in 2 patients (1 patient in double-bundle group and 1 patient in single-bundle group). KT-1000 of patients in double-bundle group was (1.5 +/- 1.2) mm, and (1.9 +/- 1.5) mm in single-bundle group, there were no statistically significant differences between the two groups. Arthroscopic single-bundle reconstruction and double-bundle anterior cruciate ligament

  8. "Anatomic" single-bundle anterior cruciate ligament reconstruction reduces both anterior translation and internal rotation during the pivot shift.

    PubMed

    Porter, Mark D; Shadbolt, Bruce

    2014-12-01

    The ability of single-bundle anterior cruciate ligament (ACL) reconstruction to restore rotational control has been questioned by proponents of the double-bundle technique. The term anatomic positioning has become popularized in recognition of the incorrect positioning sometimes used in the past, which may have contributed to the lack of rotation control. The pivot-shift test remains the most clinically useful measure of ACL deficiency, and it is now possible to measure it both accurately and objectively using computer navigation. Single-bundle ACL reconstruction will reduce anterior translation and internal rotation of the tibia during the pivot-shift test when compared with the contralateral uninjured knee. Descriptive laboratory study. A total of 20 patients with an acute isolated ACL rupture underwent reconstruction with a single-bundle autologous hamstring graft. Computer navigation was used intraoperatively to plot the pivot shift before and after reconstruction. The opposite uninjured knee was used as a control. Statistical analysis was used to compare the pivot shifts before and after surgery. Single-bundle ACL reconstruction produced a significant reduction in anterior translation, from a mean ± SD of 17.4 ± 3.80 mm to 6.4 ± 1.95 mm (P < .001), as well as in internal rotation, from 22.9° ± 5.91° to 7.5° ± 2.96° (P < .001). The anterior translation in the reconstructed knees was similar to the control knees, 6.4 ± 1.95 mm versus 5.6 ± 1.23 mm (P < .148), while the internal rotation was significantly less in the reconstructed knees, 7.5° ± 2.96° versus 11.9° ± 3.36° (P < .05). The values for the coupled movements were used to calculate the length of the radius of curvature, about which the tibia rotates relative to the femur, during the pivot shift. In the control knees, the mean value was 28.9 ± 8.21 mm, while there was extreme variability in the operated knee both before and after surgery. It is possible to reduce both anterior

  9. An in Vivo 3D Computed Tomographic Analysis of Femoral Tunnel Geometry and Aperture Morphology Between Rigid and Flexible Systems in Double-Bundle Anterior Cruciate Ligament Reconstruction Using the Transportal Technique.

    PubMed

    Kim, Jae Gyoon; Chang, Min Ho; Lim, Hong Chul; Bae, Ji Hoon; Lee, Seung Yup; Ahn, Jin Hwan; Wang, Joon Ho

    2015-07-01

    The aim of this study was to compare femoral tunnel length, femoral graft-bending angle, posterior wall breakage, and femoral aperture morphologic characteristics between rigid and flexible systems after double-bundle (DB) anterior cruciate ligament (ACL) reconstruction using the transportal (TP) technique. We evaluated 3-dimensional computed tomography (3D-CT) results for 54 patients who underwent DB ACL reconstruction using the TP technique with either a flexible system (n = 27) or a rigid system (n = 27). The femoral tunnel length, femoral graft-bending angle, posterior wall breakage, femoral tunnel aperture height to width (H:W) ratio, aperture axis angle, and femoral tunnel position were assessed using OsiriX Imaging Software and Geomagic Qualify 2012 (Geomagic, Cary, NC). The mean anteromedial (AM) femoral tunnel length of the flexible group was significantly longer than that of the rigid group (P = .009). The mean femoral graft-bending angles in the flexible group were significantly less acute than those in the rigid group (AM, P < .001; posterolateral [PL], P = .003]. Posterior wall breakage was observed in both groups (P = 1.00). The mean H:W ratios in the rigid group were significantly larger (more elliptical) than those of the flexible group (AM, P < .001; PL, P = .006). The mean aperture axis angle of the PL femoral tunnel in the rigid group was more parallel to the femoral shaft axis than that in the flexible group (P < .001). There were no significant differences in femoral tunnel position between the 2 groups. The AM femoral tunnel length and the AM/PL femoral graft-bending angle of the flexible system were significantly longer and less acute than those of the rigid system. However, the aperture morphologic characteristics of the AM/PL femoral tunnel and the aperture axis angle of the PL femoral tunnel in the rigid system were significantly more elliptical and closer to parallel to the femoral shaft axis than those of the flexible system. Level

  10. Single-bundle versus double-bundle ACL reconstructions in isolation and in conjunction with extra-articular iliotibial band tenodesis.

    PubMed

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

    2013-01-01

    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. 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. Controlled Laboratory Design. 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. 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 12.4(+1.0), p-value 0.009] with the cutting of the

  11. 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

  12. Anterior transposition of the inferior oblique. Anatomic assessment of the neurovascular bundle.

    PubMed

    Stager, D R; Weakley, D R; Stager, D

    1992-03-01

    Anterior transposition of the inferior oblique insertion has been described as an effective procedure for weakening the inferior oblique and for decreasing dissociated vertical deviation. It has been postulated that this occurs by converting the inferior oblique muscle from an elevator to a depressor. We found histologic, radiologic, and clinical evidence that anterior transposition of the inferior oblique muscle converts it to a depressor by means of the firm posterior attachment of the inferior oblique muscle at the site of its neurovascular bundle. This new functional insertion at the neurovascular bundle created by the anterior transposition allows for the depressor effect seen after this procedure.

  13. Single-bundle patellar tendon versus non-anatomical double-bundle hamstrings ACL reconstruction: a prospective randomized study at 8-year minimum follow-up.

    PubMed

    Zaffagnini, Stefano; Bruni, Danilo; Marcheggiani Muccioli, Giulio Maria; Bonanzinga, Tommaso; Lopomo, Nicola; Bignozzi, Simone; Marcacci, Maurilio

    2011-03-01

    The purpose of this study was to compare subjective, objective and radiographic outcome of the lateralized single-bundle bone-patellar tendon-bone autograft with a non-anatomical double-bundle hamstring tendons autograft anterior cruciate ligament (ACL) reconstruction technique at long-term follow-up. Seventy-nine non-consecutive randomized patients (42 men; 37 women) with unilateral ACL insufficiency were prospectively evaluated, before and after ACL reconstruction by means of the above-mentioned techniques, with a minimum follow-up of 8 years (range 8-10 years; mean 8.6 years). In the double-bundle hamstrings technique, we used one tibial and one femoral tunnel combined with one "over-the-top" passage, cortical staple's fixation and we left intact hamstrings' tibial insertion. Patients were evaluated subjectively and objectively, using IKDC score, Tegner level, manual maximum displacement test with KT-2000™ arthrometer. Radiographic evaluation was performed according to IKDC grading system, and re-intervention rate for meniscal lesions was also recorded. The subjective and objective IKDC were similar in both groups while double-bundle hamstrings group showed significantly higher Tegner level (P = 0.0007), higher passive range of motion recovery (P = 0.0014), faster sport resumption (P = 0.0052), lower glide pivot-shift phenomenon (P = 0.0302) and lower re-intervention rate (P = 0.0116) compared with patellar tendon group. Radiographic evaluation showed significant lower objective degenerative changes in double-bundle hamstrings group at final follow-up (P = 0.0056). Although both techniques provide satisfactory results, double-bundle ACL reconstruction shows better functional results, with a faster return to sport activity, a lower re-operation rate and lower degenerative knee changes.

  14. MRI depiction and 3D visualization of three anterior cruciate ligament bundles.

    PubMed

    Otsubo, H; Akatsuka, Y; Takashima, H; Suzuki, T; Suzuki, D; Kamiya, T; Ikeda, Y; Matsumura, T; Yamashita, T; Shino, K

    2017-03-01

    The anterior cruciate ligament (ACL) is divided into three fiber bundles (AM-M: anteromedial-medial, AM-L: anteromedial-lateral, PL: posterolateral). We attempted to depict the three bundles of the human ACL on MRI images and to obtain 3-dimensional visualization of them. Twenty-four knees of healthy volunteers (14 males, 10 females) were scanned by 3T-MRI using the fat suppression 3D coherent oscillatory state acquisition for the manipulation of imaging contrast (FS 3D-COSMIC). The scanned images were reconstructed after the isotropic voxel data, which allows the images to be reconstructed in any plane, was acquired. We conducted statistical examination on the identification rate of the three ACL bundles by 2D planes. Segmentation and 3D visualization of the fiber bundles using volume rendering were performed. The triple-bundle ACL was best depicted in the oblique axial plane. While the AM-M and AM-L bundles were clearly depicted in all cases, the PL bundle was not clearly visualized in two knees (8%). Therefore, the three ACL bundles were depicted in 22 knees (92%). The results of 3D visualization of the fiber arrangement agreed well with macroscopic findings of previous anatomical studies. 3T-MRI and the isotropic voxel data from FS 3D-COSMIC made it possible to demonstrate the identifiable depiction of three ACL bundles in nearly all cases. 3D visualization of the bundles could be a useful tool to understand the ACL fiber arrangement. Clin. Anat. 30:276-283, 2017. 2016 The Authors. Clinical Anatomy published by Wiley Periodicals, Inc. on behalf of American Association of Clinical Anatomists.

  15. Promising short-term results following selective bundle reconstruction in partial anterior cruciate ligament tears.

    PubMed

    Abat, Ferran; Gelber, Pablo Eduardo; Erquicia, Juan I; Pelfort, Xavier; Tey, Marc; Monllau, Juan Carlos

    2013-10-01

    The different functions of the two anterior cruciate ligament (ACL) bundles have increased interest in tears of only one of these two bundles. The purpose of this study was to assess the outcome of selective reconstruction of an injured bundle of isolated anteromedial bundle (AMB) or posterolateral bundle (PLB) tears. Consecutive series of 147 ACL reconstructions was prospectively analyzed. Patients with partial ACL tears who underwent selective bundle reconstructions were studied. Stability was assessed with the Lachman, anterior-drawer and pivot-shift tests and KT-1000. Functional assessment was performed with Lysholm and Tegner questionnaires. The preoperative MRI was analyzed to detect differences from arthroscopic findings. Twenty-eight patients (19%) were included. The minimum follow-up period was 30months. Eighteen had AMB and 10 PLB tears. Only 19% of their MRI's were categorized as partial ACL tears. The Lysholm score improved from 66.1/65.5 to 96.6/95.2 in the AMB/PLB groups, respectively (p<0.001). The same or no more than one level lower Tegner score was restored. The pivot-shift, Lachman and anterior-drawer tests were negative in all cases (p<0.001). Two reconstructed AMBs developed extension loss due to Cyclops lesions and were resolved surgically. The technique provided excellent functional scores with normalized stability and a return to previous level of activity with a low rate of minor complications at a minimum 2.5years' follow-up. Arthroscopic examination was the most reliable tool for properly diagnosing and treating a condition observed in almost one out of every five ACL reconstructed knee in this series. Therapeutic case series; level 4. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. 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

  17. Superconductivity in bundles of double-wall carbon nanotubes.

    PubMed

    Shi, Wu; Wang, Zhe; Zhang, Qiucen; Zheng, Yuan; Ieong, Chao; He, Mingquan; Lortz, Rolf; Cai, Yuan; Wang, Ning; Zhang, Ting; Zhang, Haijing; Tang, Zikang; Sheng, Ping; Muramatsu, Hiroyuki; Kim, Yoong Ahm; Endo, Morinobu; Araujo, Paulo T; Dresselhaus, Mildred S

    2012-01-01

    We present electrical and thermal specific heat measurements that show superconductivity in double-wall carbon nanotube (DWCNT) bundles. Clear evidence, comprising a resistance drop as a function of temperature, magnetoresistance and differential resistance signature of the supercurrent, suggest an intrinsic superconducting transition below 6.8 K for one particular sample. Additional electrical data not only confirm the existence of superconductivity, but also indicate the T(c) distribution that can arise from the diversity in the diameter and chirality of the DWCNTs. A broad superconducting anomaly is observed in the specific heat of a bulk DWCNT sample, which yields a T(c) distribution that correlates well with the range of the distribution obtained from the electrical data. As quasi one dimensionality of the DWCNTs dictates the existence of electronic density of state peaks, confirmation of superconductivity in this material system opens the exciting possibility of tuning the T(c) through the application of a gate voltage.

  18. Differences in the microstructural properties of the anteromedial and posterolateral bundles of the anterior cruciate ligament.

    PubMed

    Skelley, Nathan W; Castile, Ryan M; York, Timothy E; Gruev, Viktor; Lake, Spencer P; Brophy, Robert H

    2015-04-01

    Tissue properties of the anteromedial (AM) and posterolateral (PL) bundles of the anterior cruciate ligament (ACL) have not been previously characterized with real-time dynamic testing. The current study used a novel polarized light technique to measure the material and microstructural properties of the ACL. The AM and PL bundles of the ACL have similar material and microstructural properties. Controlled laboratory study. The AM and PL bundles were isolated from 16 human cadaveric ACLs (11 male, 5 female; average age, 41 years [range, 24-53 years]). Three samples from each bundle were loaded in uniaxial tension, and a custom-built polarized light imaging camera was used to quantify collagen fiber alignment in real time. A bilinear curve fit was applied to the stress-strain data of a quasistatic ramp-to-failure to quantify the moduli in the toe and linear regions. Fiber alignment was quantified at zero strain, the transition point of the bilinear fit, and in the linear portion of the stress-strain curve by computing the degree of linear polarization (DoLP) and angle of polarization (AoP), which are measures of the strength and direction of collagen alignment, respectively. Data were compared using t tests. The AM bundle exhibited significantly larger toe-region (AM 7.2 MPa vs. PL 4.2 MPa; P < .001) and linear-region moduli (AM 27.0 MPa vs. PL 16.1 MPa; P = .017) compared with the PL bundle. Average DoLP values were similar at low strain but were significantly larger (ie, more uniform alignment) for the AM bundle in the linear region of the stress-strain curve (AM 0.22 vs. PL 0.19; P = .036) compared with the PL bundle. The standard deviation AoP values was larger for the PL bundle at both transition (P = .041) and linear-region strain (P = .014), indicating more disperse orientation. Material and microstructural properties of the AM and PL bundles of the ACL differ during loading. The AM bundle possessed higher tissue modulus and failure stress, as well as more

  19. Double-bundle reconstruction cannot restore intact knee kinematics in the ACL/LCL-deficient knee.

    PubMed

    Zantop, Thore; Schumacher, Tobias; Schanz, Steffen; Raschke, Michael J; Petersen, Wolf

    2010-08-01

    The aim of this study was to evaluate the effect of single-bundle (SB) and anatomic double-bundle (DB) anterior cruciate ligament (ACL) reconstruction on the resulting knee kinematics in a simulated clinical setting with ACL rupture and associated extra-articular damage to the lateral structures. It was hypothesized that anatomic DB ACL reconstruction restores the intact knee kinematics in ACL/LCL-deficient knees, whereas SB ACL reconstruction fails to restore the intact knee kinematics. Ten fresh-frozen human cadaver knees were subjected to anterior tibial load of 134 N (simulated KT 1000) and combined rotatory load of 10-Nm valgus and 4-Nm internal tibial torque (simulated pivot shift) using a robotic/UFS testing system. The resulting knee kinematics was determined for intact, ACL/LCL-deficient, SB ACL-reconstructed/LCL-deficient, and DB ACL-reconstructed/LCL-deficient knee. Statistical analysis was performed using a two-way ANOVA test with the level of significance set at P < 0.05. Under a simulated KT 1000 test, anterior tibial translation (ATT) following SB ACL reconstruction was statistically significant at 0 degrees , 30 degrees and 60 degrees of knee flexion when compared to the intact knee. ATT after DB ACL reconstruction showed no statistically significant difference from the intact knee; however, there was a significant difference in SB reconstruction at 0 degrees and 30 degrees of knee flexion. Under a simulated pivot shift test, both SB and DB ACL reconstruction failed to restore the intact knee kinematics. The results of the study did not support our initial hypothesis. Though DB reconstructions were significantly superior to SB reconstruction under simulated KT 1000 test, SB as well as DB reconstruction failed to restore the intact kinematics under simulated pivot shift loads. The clinical relevance of this study is that caution and precise preoperative diagnostics are needed to avoid failure of intra-articular ACL reconstruction if the extra

  20. Comparison of outcome after anatomic double-bundle and antero-medial portal non-anatomic single-bundle reconstruction in ACL-injured patients.

    PubMed

    Karikis, Ioannis; Ahldén, Mattias; Casut, Abraham; Sernert, Ninni; Kartus, Jüri

    2017-04-01

    The aim of this study was to compare anatomic double-bundle anterior cruciate ligament reconstruction with non-anatomic single-bundle reconstruction. In a prospective consecutive series, 94 unselected patients [45 anatomic double-bundle (ADB) and 49 non-anatomic single-bundle (SB)] underwent ACL reconstruction involving hamstring tendon autograft, interference screw fixation on both the femoral and tibial side and drilling the femoral tunnel(s) through the antero-medial portal in both groups. In the ADB group, the remnants of the ACL were identified and the grafts were placed anatomically. In the SB group, traditional placement of the graft was performed in a less anatomic manner. Pre-operatively, the groups were comparable in terms of age, gender, time between injury and operation and associated injuries. One independent physiotherapist performed all the pre-operative and post-operative assessments. The follow-up period was 26 (22-34) and 24 (23-30) months in the ADB and SB groups, respectively (p = 0.005). At follow-up, 78 % in the ADB group and 74 % in the SB group had a negative pivot-shift test (n.s.). The KT-1000 134N measurements were 2 (-5 to 10.5) and 2 (-4 to 7) mm in the ADB and SB groups, respectively (n.s.). At follow-up, the extension deficit was significantly larger in the ADB group than in the SB group (p = 0.001). The Tegner activity scale was significantly higher in the ADB group both pre-operatively and at follow-up (p = 0.03 and p = 0.004). In overall terms, both groups had improved significantly at the two-year follow-up. In an unselected group of ACL-injured patients, anatomic double-bundle reconstruction did not result in better rotational or antero-posterior stability measurements than antero-medial portal non-anatomic single-bundle reconstruction at the two-year follow-up. III.

  1. The concept of double bundle ACL simulation with a single bundle patellar tendon graft. A cadaveric feasibility study.

    PubMed

    Jacobi, Matthias; Magnussen, Robert A; Villa, Vincent; Demey, Guillaume; Neyret, Philippe

    2012-06-07

    There is significant interest in the restoration of the double-bundle anatomy of the native ACL when performing ACL reconstruction. Possible techniques include those utilizing two separate grafts with independent tunnels and those that attempt to mimic this anatomy with a single graft and fewer tunnels. Many of the latter techniques require specific instrumentation and are technically challenging. We demonstrate that the double-bundle anatomy of the native ACL can theoretically be mimicked by a single-bundle reconstruction. We performed single bundle ACL reconstruction with a bone-patellar tendon-bone (BTB) graft in two cadaveric knees. Both grafts were placed to mimic the native ACL footprints - one reconstruction was performed with rectangular bone blocks and oval tunnels and one was performed utilizing a standard BTB graft and round tunnels. Qualitative assessment of graft behavior was made as the knees were taken through a range of motion. The ACL graft was able to qualitatively mimic the behavior of the native ACL in both knees provided the bone blocks were correctly orientated. ACL reconstruction with a single BTB graft can qualitatively mimic the behavior of the two bundles of the native ACL. The key to ensuring this behavior was noted to be appropriate orientation of the graft in the tunnels. Quantitative biomechanical investigations are necessary to evaluate the impact of graft orientation on function.

  2. Biomechanical characterization of double-bundle femoral press-fit fixation techniques.

    PubMed

    Ettinger, M; Haasper, C; Hankemeier, S; Hurschler, C; Breitmeier, D; Krettek, C; Jagodzinski, M

    2011-03-01

    Press-fit fixation of patellar tendon bone anterior cruciate ligament autografts is an interesting technique because no hardware is necessary. To date, no biomechanical data exist describing an implant-free double-bundle press-fit procedure. The purpose of this study was to characterize the biomechanical properties of three double-bundle press-fit fixations. In a controlled laboratory study, the patellar-, quadriceps- and hamstring tendons of 10 human cadavers (age: 49.2 ± 18.5 years) were used. An inside out press-fit fixation with a knot in the semitendinosus and gracilis tendons (SG) combined with an additional bone block, with two quadriceps tendon bone block grafts (QU) was compared with press-fit fixation of two bone patellar tendon bone block (PT) grafts in 30 porcine femora. Constructs were cyclically stretched and then loaded until failure. Maximum load to failure, stiffness and elongation during failure testing and cyclical loading were investigated. The maximum load to failure was 703 ± 136 N for SG fixation, 632 ± 130 N for QU and 656 ± 127 N for PT fixation. Stiffness of the constructs averaged 138 ± 26 N/mm for SG, 159 ± 74 N/mm for QU, and 154 ± 50 N/mm for PT fixation. Elongation during initial cyclical loading was 1.2 ± 1.4 mm for SG, 2.0 ± 1.4 mm for QU, and 1.0 ± 0.6 mm for PT (significantly larger for PT and QU between the first 5 cycles compared with cycles 15-20th, P < 0.01). All investigated double-bundle fixation techniques were equal in terms of maximum load to failure, stiffness, and elongation. Unlike with single-bundle press-fit fixation techniques that have been published, no difference was observed between pure tendon combined with an additional bone block and tendon bone grafts. All techniques exhibited larger elongation during initial cyclical loading. All three press-fit fixation techniques that were investigated exhibit comparable biomechanical properties. Preconditioning of the constructs

  3. Single-Bundle Anatomic Anterior Cruciate Ligament Reconstruction: Surgical Technique Pearls and Pitfalls.

    PubMed

    Malempati, Chaitu S; Metzler, Adam V; Johnson, Darren L

    2017-01-01

    Anterior cruciate ligament (ACL) ruptures are some of the most common sports-related injuries. Treatment of these injuries with ACL reconstruction has evolved over the last several decades. Anatomic single-bundle ACL reconstruction offers an accurate and reproducible method to reproduce native knee anatomy, restore knee kinematics, and ultimately restore function and decrease long-term degenerative effects. The importance of adequate arthroscopic visualization and a thorough understanding of the native anatomic ACL landmarks are discussed in this article. Furthermore, surgical technique, pearls, pitfalls, potential complications, rehabilitation, and outcomes are reviewed.

  4. [Intervention among patients with right bundle branch block and left anterior hemiblock. Operatory risk (author's transl)].

    PubMed

    Coriat, P; Harari, A; Tarot, J P; Ducardonnet, A; Viars, P

    1981-01-01

    In order to assess the risk of advanced heart block during anesthesia in patients with right bundle branch block and left anterior hemiblock, 35 consecutive patients were monitored throughout the pre-, intra- and postoperative period. As conventional ECG monitoring may only detect advanced atrioventricular block, patients were monitored according to the Holter method which can easily detect even minor changes of atrioventricular conduction namely slight increased PR interval or dropped P wave. All patients were asymptomatic, in normal sinus rhythm without second degree AV block. Surgical procedures were performed under general anesthesia (n = 15) and epidural anesthesia using lidocaine (n = 20). No episode of second or third degree atrioventricular block occurred. The only modifications observed were rare and transient increase of PR, occurring during surgical procedures in 5 patients, always associated with a sinus bradycardia. They immediately regressed at the termination of the sinus bradycardia either spontaneously or following atropine injection, strongly suggesting the responsability of increased vagal tone. Thus general or epidural anesthesia did not compromise infranodal conduction in any of the observed patients. These data indicate that anesthesia can be safely used without prophylactic preoperative insertion of pacemakers in patients with asymptomatic chronic right bundle branch block and left anterior hemi-block.

  5. Associations between isolated bundle tear of anterior cruciate ligament, time from injury to surgery, and clinical tests.

    PubMed

    Fok, August Wai-Ming; Yau, W P

    2014-08-01

    To evaluate the associations between isolated anteromedial (AM) or posterolateral (PL) bundle tear of the anterior cruciate ligament (ACL), the time from injury to surgery, and various clinical tests. 36 women and 189 men aged 16 to 52 (mean, 26.4) years underwent ACL reconstruction of the right (n=107) and left (n=118) knees. Patients were evaluated for the International Knee Documentation Committee Subjective Knee Score, Cincinnati Knee Rating System Score, anterior drawer test, Lachman test, pivot shift test, KT1000 arthrometer measurement, isokinetic muscle tests of the extensors, and functional tests (single leg hop and timed hop test). Examination under anaesthesia (EUA) was also performed, followed by diagnostic arthroscopy. The integrity of the ACL bundles was tested using a probe. The AM and PL bundles were morphologically intact if structurally present, and functionally intact if not lax on probing. Of the 225 patients, 8 had isolated AM bundle tears, 2 had isolated PL bundle tears, and 215 had complete ACL tears in terms of function. The corresponding numbers were 30, 13, and 182 in terms of morphology. Compared with patients with complete ACL tear, the mean time from injury to surgery was significantly shorter in patients with isolated AM or PL bundle tear in terms of function (17.5 vs. 5.6 months, p<0.001) and morphology (17.5 vs. 8.8 months, p<0.001). Compared with patients with complete ACL tear, those with a functionally intact PL bundle had a higher rate of negative pivot shift test in preoperative evaluation (1% vs. 17%, p=0.002) and EUA (1% vs. 63%, p<0.001), and had a higher rate of negative Lachman test in EUA (1% vs. 25%, p=0.02). The time from injury to surgery was shorter in patients with isolated bundle ACL tear. In patients with ACL deficiency, the pivot shift test was useful in detecting an intact PL bundle.

  6. Excess mortality and morbidity associated with right bundle branch and left anterior fascicular block.

    PubMed

    Pine, M B; Oren, M; Ciafone, R; Rosner, B; Hirota, Y; Rabinowitz, B; Abelmann, W H

    1983-05-01

    Excess mortality and morbidity associated with right bundle branch and left anterior fascicular block were evaluated in 108 patients with block (age 74 +/- 10 years, 69% male) and 108 age- and sex-matched control patients with normal conduction. Clinical characteristics were similar initially except for more congestive heart failure in patients with block. Life table analysis revealed a higher 12 year mortality with block, even after omitting patients with moderate or severe congestive heart failure (risk ratio 1.47, p less than 0.05). Compared with control subjects, the group of patients with block had more sudden death and deaths of unknown cause, but a similar number of noncardiac and diagnosed cardiac deaths. More patients with block developed new second and third degree atrioventricular block or new overt coronary artery disease, but this finding did not support prophylactic pacing in asymptomatic patients. The importance of internal controls in assessing the natural history of clinical and electrocardiographic abnormalities is emphasized.

  7. Effect of anteromedial and posterolateral anterior cruciate ligament bundles on resisting medial and lateral tibiofemoral compartment subluxations.

    PubMed

    Gardner, Eric J; Noyes, Frank R; Jetter, Andrew W; Grood, Edward S; Harms, Samuel P; Levy, Martin S

    2015-05-01

    This study analyzed the interaction of the anteromedial and posterolateral portions of the anterior cruciate ligament (ACL) in resisting medial and lateral tibiofemoral compartment subluxations under multiple loading conditions. By use of a 6-df robotic simulator, 10 human cadaveric knees were tested in 3 states: intact ACL, partial ACL (loss of either the anteromedial bundle [AMB] or posterolateral bundle [PLB]), and deficient ACL. The testing profile involved anterior-posterior translation and internal-external rotation, as well as 3 pivot-shift loading conditions with varying internal rotation torque (1- or 5-Nm) and coupled anterior force (35- or 100-N). Digitization of anatomic landmarks provided tibiofemoral compartment translations and centers of tibial rotation. During pivot-shift testing (100-N anterior force, 1-Nm internal rotation torque, and 7-Nm valgus), the lateral and medial compartment anterior translation increased by a mean of 2.5 ± 0.8 mm (P = .016) and 3.4 ± 2.0 mm (P = .001), respectively, on AMB sectioning and 1.3 ± 0.9 mm (P = .329) and 0.6 ± 0.7 mm (P = .544), respectively, on PLB sectioning. Higher internal rotation torque (5 Nm v 1 Nm) on pivot-shift testing reduced central and medial anterior translation after ACL sectioning. There was no change in internal rotation on AMB or PLB sectioning. During the Lachman test (100-N), AMB and PLB sectioning increased central translation by 3.6 ± 1.6 mm (P = .001) and 0.7 ± 0.6 mm (P = .498), respectively. Both ACL bundles function synergistically in resisting medial and lateral compartment subluxations on the Lachman and pivot-shift tests. The AMB provided more restraint to anterior tibial translation during both tests as compared with the PLB. PLB sectioning produced no statistically significant change in anterior translation on the Lachman or pivot-shift test. Neither bundle contributed to resisting internal rotation. An ACL graft designed to duplicate the AMB would theoretically

  8. Microstructural properties and mechanics vary between bundles of the human anterior cruciate ligament during stress-relaxation.

    PubMed

    Castile, Ryan M; Skelley, Nathan W; Babaei, Behzad; Brophy, Robert H; Lake, Spencer P

    2016-01-04

    Previous studies have shown different elastic properties between the anteromedial (AM) and posterolateral (PL) bundles of the human anterior cruciate ligament (ACL). However, it is unknown if the two bundles of the ACL exhibit distinct time-dependent properties and microstructural organization, which have important implications for fully understanding the structure-function relationships of this oft-injured ligament. The goal of this study was to quantify the viscoelastic material properties and collagen fiber alignment of the AM and PL bundles in 16 human ACLs during stress-relaxation mechanical tests using the quasi-linear viscoelastic (QLV) model and a quantitative polarization imaging technique. We hypothesized that the AM and PL bundles would exhibit differences in the instantaneous mechanical and organizational properties (i.e., immediately following a step increase in strain), but similar time-dependent changes during stress-relaxation. Results showed that AM samples exhibited larger peak/equilibrium stresses and less stress-relaxation during a 300-s hold compared to PL samples. The AM bundle demonstrated stronger and more uniform collagen fiber alignment (i.e., higher degree of linear polarization (DoLP) values and less distributed angle of polarization (AoP) values) compared to the PL bundle, and larger changes in alignment strength during the hold. Results suggest that the AM bundle is the more "dominant" bundle, with significantly different mechanical and material properties in stress-relaxation. While more research is needed to better understand how these findings relate to the pathophysiology of ACL tears and can best guide treatment, the findings provide additional insight into the microstructural properties and biomechanics of the human ACL. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Detection of left anterior descending coronary artery disease in patients with left bundle branch block.

    PubMed

    Civelek, A C; Gozukara, I; Durski, K; Ozguven, M A; Brinker, J A; Links, J M; Camargo, E E; Wagner, H N; Flaherty, J T

    1992-12-15

    The detection of coronary artery disease is difficult if a patient has electrocardiographic evidence of left bundle branch block (BBB). Septal blood flow may be reduced in patients with left BBB, despite no angiographic evidence of left anterior descending (LAD) coronary artery disease. We have developed a new method of quantification of Thallium-201 single-photon emission computed tomographic (SPECT) images with the aim of better separating patients with left BBB and LAD disease from those with left BBB alone. The study cohort comprised 8 normal subjects (group I) and 20 patients with left BBB and chest pain who underwent thallium-201 SPECT imaging and coronary angiography. Eight patients (group II) had < or = 50% LAD stenosis, and 12 (group III) had > or = 70% LAD stenosis. Septal abnormality scores on the second short-axis slice from the base were computed, based on comparison of each subject's short-axis circumferential profile with a normal reference curve. This followed a procedure in which each profile was scaled to minimize differences in its absolute level in relation to the reference curve. Septal abnormality scores on stress images were 0.8 +/- 22 for group I, 27 +/- 43 for group II, and 165 +/- 67 for group III (p = 0.15 for group I vs II, and p < 0.0001 between groups I and III, and II and III).(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Finite element study on the anatomic transtibial technique for single-bundle anterior cruciate ligament reconstruction.

    PubMed

    Bae, Ji Yong; Kim, Geon-Hee; Seon, Jong Keun; Jeon, Insu

    2016-05-01

    The anatomic transtibial (TT) technique is proposed as a new approach for single-bundle anterior cruciate ligament (ACL) reconstruction. Geometric models of the anatomic TT and anteromedial (AM) portal techniques were fabricated with a reconstructed knee joint model and virtual surgical operations. Grafts of 7 mm diameter were modeled and inserted into tunnels drilled in each model. In the models, the shape of the graft between the femur and the tibia, the lengths of the bone tunnels, and the femoral graft bending angles were evaluated. To evaluate the biomechanical effects of both techniques on the grafts, the contact pressures and maximum principal stresses in the grafts were calculated using the finite element method. The anatomic TT technique placed the femoral tunnel to the anatomic position of the native ACL femoral attachment site. In addition, it decreased the peak contact pressure and the maximum principal stress at the full extension position of the graft compared with the AM portal technique. The anatomic TT technique may be regarded as a superior surgical technique compared with the conventional TT and AM portal techniques. Because of the easy surgical operation involved, the technique decreases the operation time for ACL reconstruction and it provides a deformation behavior of grafts similar to that in the native ACL in a knee joint. With its few side effects, the anatomic TT technique may considerably help patients.

  11. Morphologic evaluation of remnant anterior cruciate ligament bundles after injury with three-dimensional computed tomography.

    PubMed

    Adachi, Nobuo; Ochi, Mitsuo; Takazawa, Kobun; Ishifuro, Minoru; Deie, Masataka; Nakamae, Atsuo; Kamei, Goki

    2016-01-01

    This study aimed to investigate the morphological patterns of remnant anterior cruciate ligament bundles after injury (ACL remnant) on three-dimensional computed tomography (3DCT) and compare them with those on arthroscopy. Sixty-three patients (33 males and 30 females; mean age 25.2 ± 10.1 years) who had undergone primary ACL reconstruction between March 2011 and December 2012 were included in this study. The average durations between traumas and 3DCT and between 3DCT and surgery were 101.7 ± 87.2 and 38.2 ± 38.7 days, respectively. ACL remnants were classified into four morphological patterns on 3DCT. 3DCT findings were compared with arthroscopic findings with and without probing. The morphological patterns of the ACL remnants on 3DCT were well matched with those on arthroscopy without probing (the concordance rate was 77.8%). However, the concordance rate was reduced to 49.2% when arthroscopic probing was used to confirm the femoral attachment of ACL remnants (p ≤ 0.05). This study demonstrates that the morphological patterns of ACL remnants on 3DCT were well matched with those on arthroscopy without probing. Therefore, the technique can be useful for preoperative planning of the ACL reconstruction or informed consent to the patients. However, for definitive diagnosis, arthroscopic probing is required. IV.

  12. Comparing Transtibial and Anteromedial Drilling Techniques for Single-bundle Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Sukur, Erhan; Akman, , Yunus Emre; Senel, , Ahmet; Unkar, Ethem Ayhan; Topcu, , Huseyin Nevzat; Ozturkmen, , and Yusuf

    2016-01-01

    Background: Among the many factors that determine the outcome following anterior cruciate ligament (ACL) reconstruction, the position of the femoral tunnel is known to be critically important and is still the subject of extensive research. Objective: We aimed to retrospectively compare the outcomes of arthroscopic ACL reconstruction using transtibial (TT) or anteromedial (AMP) drilling techniques for femoral tunnel placement. Methods: ACL reconstruction was performed using the TT technique in 49 patients and the AMP technique in 56 patients. Lachman and pivot-shift tests, the Lysholm Knee Scale, International Knee Documentation Committee (IKDC) score, Tegner activity scale and visual analog scale (VAS) were used for the clinical and functional evaluation of patients. Time to return to normal life and time to jogging were assessed in addition to the radiological evaluation of femoral tunnel placement. Results: In terms of the Lysholm, IKDC, Tegner score, and stability tests, no significant differences were found between the two groups (p > 0.05). Statistical analysis revealed reduced time to return to normal life and jogging in the AMP group (p < 0.05). The VAS score was also significantly reduced in the AMP group (p < 0.05). The position of the femoral tunnel was anatomically appropriate in 51 patients in the AMP group and 5 patients in the TT group. Conclusion: The AMP technique is superior to the TT technique in creating anatomical femoral tunnel placement during single-bundle ACL reconstruction and provides faster recovery in terms of return to normal life and jogging at short-term follow-up. PMID:27733884

  13. Late spontaneous resolution of a double anterior chamber post deep anterior lamellar keratoplasty.

    PubMed

    Passani, Andrea; Sframeli, Angela Tindara; Loiudice, Pasquale; Nardi, Marco

    2017-01-01

    A 31-year-old healthy male underwent deep anterior lamellar keratoplasty with big-bubble technique for treatment of keratoconus in his right eye. One week after surgery, he presented with detachment of the endothelium-Descemet complex with formation of a double anterior chamber, despite the apparent absence of an intraoperative Descemet membrane rupture. A subsequent intervention with the intent to relocate the corneal graft button was not effective, because the detachment appeared again one day later. The authors hypothesized that, at the time of the stromal dissection with big bubble technique, a small amount of air penetrated into the anterior chamber, creating a false pathway through the trabecular meshwork. The aqueous humor then penetrated the graft flowing through the false pathway, causing the endothelium-Descemet detachment. The persistence of that pathway, even after the intervention of graft repositioning, caused the failure of the latter procedure and persistence of the double chamber. We decided to wait and observe. The double anterior chamber spontaneously resolved in approximately three months.

  14. Specific compartmental analysis of cartilage status in double-bundle ACL reconstruction patients: a comparative study using pre- and postoperative MR images.

    PubMed

    Lee, Yong Seuk; Jeong, Yu Mi; Sim, Jae Ang; Kwak, Ji Hoon; Kim, Kwang Hee; Nam, Shin Woo; Lee, Beom Koo

    2013-03-01

    The purpose of this study was to evaluate the changes in the site-specific cartilage status after a double-bundle ACL reconstruction using preoperative and follow-up MR images. Thirty-six knees that underwent a double-bundle ACL reconstruction from 2001 to 2009 with the available preoperative and follow-up magnetic resonance imaging were included. Patients with a meniscal injury were compared with those without a meniscal injury. The cartilage morphology was classified using a 6-grade scale [from 0 = normal thickness and signal, to 6 = diffuse full-thickness loss (>75 % of the region)]. The changes in cartilage status were evaluated at 14 sites. Cartilage changes were observed in all sites and were classified according to the site and degree of change. The majority of changes were grade 0 and 1, which accounted for 68 and 16.8 % of changes, respectively. The patella medial facet and anterolateral and centromedial femoral regions showed significantly more cartilage loss than the posteromedial, centrolateral, anterolateral, and anteromedial tibial regions. No significance was observed between the knees with or without combined injuries (n.s.). On the other hand, knees with or without combined injuries showed a different pattern of cartilage change, as demonstrated by different levels of grade change at sites. The change in cartilage status was minimal after a double-bundle ACL reconstruction. The patella medial facet, lateral femur anterior region, and medial femur central region showed significantly more cartilage loss than the medial tibia posterior, lateral tibia central, lateral tibia anterior, and medial tibia anterior regions. The presence of a combined injury did not affect the cartilage status changes, even though it was underpowered and too short term to assess the influence of the meniscal injury. Case series, Level IV.

  15. Double level arterial injury with neuropraxia following anterior shoulder dislocation.

    PubMed

    Zaraa, Mourad; Sehli, Heithem; Mahjoub, Sabri; Dridi, Moez; Mbarek, Mondher

    2015-12-01

    Vascular and nervous complications are rare after shoulder dislocation. We report the case of a double level arterial injury with neuropraxia following anterior shoulder dislocation that was diagnosed by MultiDetector-row Computed Tomographic (MDCT) angiography and treated by surgical bypass graft and embolectomy. Our case is original, not only because of the rarity of these complications, but also because of the thromboembolism of brachial artery which could be undiagnosed and could compromise prognosis.

  16. Double level arterial injury with neuropraxia following anterior shoulder dislocation

    PubMed Central

    Zaraa, Mourad; Sehli, Heithem; Mahjoub, Sabri; Dridi, Moez; Mbarek, Mondher

    2015-01-01

    Vascular and nervous complications are rare after shoulder dislocation. We report the case of a double level arterial injury with neuropraxia following anterior shoulder dislocation that was diagnosed by MultiDetector-row Computed Tomographic (MDCT) angiography and treated by surgical bypass graft and embolectomy. Our case is original, not only because of the rarity of these complications, but also because of the thromboembolism of brachial artery which could be undiagnosed and could compromise prognosis. PMID:26566344

  17. Prototyping nanorod control: A DNA double helix sheathed within a DNA six-helix bundle.

    PubMed

    Wang, Risheng; Liu, Wenyan; Seeman, Nadrian C

    2009-08-28

    The control of the structure of matter is a key goal of nanoscience. DNA is an exciting molecule for control because it forms programmable intermolecular interactions. Stiff DNA structures, such as the double crossover motif, the tensegrity triangle, and the six-helix bundle (6HB) have been used to produce periodic arrays of DNA components. The 6HB motif consists of six DNA double helices flanking an inner cavity whose diameter is similar to that of a double helix. This motif appears to be an excellent candidate to sheathe and control nanorods by inserting them into the cavity, and then to control the placement and orientation of the rod by controlling the DNA sheath. Here, we prototype this kind of control by using a seventh DNA double helix as the nanorod and fixing it inside the 6HB motif.

  18. Risk of advanced heart block during extradural anaesthesia in patients with right bundle branch block and left anterior hemiblock.

    PubMed

    Coriat, P; Harari, A; Ducardonet, A; Tarot, J P; Viars, P

    1981-05-01

    Electrocardiographic recording by Holter monitoring demonstrated the absence of any modification, however minimal, of the intranodal conduction during surgical procedures under extradural anaesthesia in 20 patients with right bundle branch block (RBBB) and left anterior hemiblock (LAHB) but without symptoms. These data suggest that extradural anaesthesia can be used safely in patients with asymptomatic chronic RBBB and LAHB without prophylactic insertion of pacemakers. However, patients having experienced either syncope or transient Mobitz II second degree AV block are likely to have a trifascicular block and increased risk of advanced heart block during extradural anaesthesia.

  19. Kinematic analysis of the posterior cruciate ligament, part 2: a comparison of anatomic single- versus double-bundle reconstruction.

    PubMed

    Wijdicks, Coen A; Kennedy, Nicholas I; Goldsmith, Mary T; Devitt, Brian M; Michalski, Max P; Årøen, Asbjørn; Engebretsen, Lars; LaPrade, Robert F

    2013-12-01

    A more thorough understanding of the posterior cruciate ligament (PCL) has led to an increase in awareness and treatment of complex PCL injuries. Controversy exists about whether PCL reconstruction (PCLR) using an anatomic single-bundle (aSB) or anatomic double-bundle (aDB) technique is the most effective. An aDB PCLR provides significantly better anterior-posterior and rotatory knee stability compared with an aSB PCLR and more closely recreates normal knee kinematics. Controlled laboratory study. A total of 18 match-paired, cadaveric knees (mean age, 54.8 years; range, 51-59 years; 5 male and 4 female pairs) were used to evaluate the kinematics of an intact PCL, an aSB and aDB PCLR, and a complete sectioned PCL. A 6 degrees of freedom robotic system was used to assess knee stability with a 134-N applied posterior tibial load, 5-N·m external and internal rotation torques, 10-N·m valgus and varus rotation torques, and a coupled 100-N posterior tibial load and 5-N·m external rotation torque at 0°, 15°, 30°, 45°, 60°, 75°, 90°, 105°, and 120°. The aDB PCLR had significantly less posterior translation than the aSB PCLR at all flexion angles of 15° and greater. The largest difference in posterior translation was seen at 105° of flexion, where the aSB PCLR had 5.3 mm (P = .017) more posterior translation than the aDB PCLR. The aDB PCLR also had significantly less internal rotation than the aSB PCLR at all tested angles of 90° and greater. Neither reconstruction was able to fully restore native knee kinematics. An aDB PCLR more closely approximated native knee kinematics when compared with an aSB PCLR. Specifically, the aDB PCLR demonstrated significantly more restraint to posterior translation at flexion angles between 15° and 120° and less internal rotational laxity at high flexion angles 90° to 120°. Comparison of the 2 reconstruction techniques illustrates the time-zero kinematic advantage imparted by the addition of the posteromedial bundle

  20. 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.

  1. Clinical and angiographic importance of right bundle branch block in the setting of acute anterior myocardial infarction.

    PubMed

    Arslan, Uğur; Balcioğlu, Serhat; Tavil, Yusuf; Ozdemir, Murat; Cengel, Atiye

    2008-04-01

    To investigate functional status of patients (Killip class), left ventricular contractility, angiographic anatomy and severity of coronary lesions in patients with and without right bundle branch block (RBBB) in the setting of anterior myocardial infarction (MI). Patients who admitted to coronary care unit with the diagnosis of acute anterior MI between 1999 and 2005 were retrospectively searched from our database. Out of 792 patients, 37 had RBBB (RBBB group) either at admission or in the course of anterior MI. Forty patients who developed no intraventricular conduction defect during the course of anterior MI with the same demographic characteristics were selected as the control group. Out of 37 patients, 30 had RBBB on admission and 7 developed RBBB in the course of acute MI. Left anterior descending artery (LAD) proximal lesion was more commonly detected in the RBBB group [23 (62.2%) vs. 11 (27.5%) patients, p=0.003]. Left ventricular ejection fraction was lower (33.0+/-4.2% vs 36.7+/-4.9%, p=0.003) and end-systolic volume was higher (84.1+/-24.9 ml vs 74.6+/-22.0 ml, p=0.012) in patients with RBBB. Number of patients with high Killip grade (III and IV) was more in the RBBB group [7 (18.9%) vs 3 (7.5%), RR: 1.75, %95 CI 0.92-3.32, p=0.14], and number of patients with Killip grade I was more in the control group [34 (85.0%) vs 22 (59.5%), p=0.012]. Besides mean Killip class was higher in the RBBB group (1.65+/-0.90 vs 1.25+/-0.67, p=0.03). Three patients (8.1%) in the RBBB group and 2 patients (5.0%) in the control group died during hospitalization (p=0.67). Left ventricular ejection fraction decreases and Killip grade increases in case of RBBB in the setting of acute anterior MI. Culprit lesion in patients with RBBB is more commonly a LAD proximal lesion and threatened myocardial tissue is larger in patients with RBBB.

  2. Double bundle tendon graft for rotational stabilization of lunate implant arthroplasty.

    PubMed

    Henry, Mark

    2011-03-01

    Kienbock's disease can lead to unsalvageable collapse of the lunate due to avascular necrosis but with reasonably intact cartilage surfaces preserved at the head of the capitate and lunate fossa of the radius. An emerging alternative to traditional treatments for this stage is lunate implant arthroplasty with a hard material. Although, the problem of osteolysis previously seen with silicone implant arthroplasty is expected to be overcome, stabilization of both the implant and the carpus as a whole remains a challenge. The described surgical technique uses a double bundle tendon graft to stabilize the lunate implant against both excessive translational as well as sagittal plane rotational motions. The strategy also stabilizes the scaphoid and the carpus against intercalated segment instability and collapse.

  3. Spontaneous resolution of double anterior chamber with perforation of Descemet's membrane in deep anterior lamellar keratoplasty.

    PubMed

    Venkatraman, Arvind

    2012-05-01

    Deep anterior lamellar keratoplasty (DALK) using Dr. Anwar's big bubble technique was performed for a patient with granular dystrophy. Intraoperatively, a perforation of the Descemet's membrane (DM) was noted inferonasally. Though the surgery was completed, the donor graft appeared to have an intact endothelium, which was inadvertently left behind by the surgeon. Intraoperatively, there was a perforation of inferonasal DM and surgery was completed by inadvertently placing a donor with an intact endothelium. Postoperatively the patient presented with a complete DM detachment and a resultant double anterior chamber (DAC). In spite of two attempts at an air tamponade on the first and fifth post operative days, the DAC still persisted. Surprisingly, during the 6(th) week follow up visit, there was a complete resolution of the DAC as well as total recovery of vision. This interesting case clearly exemplifies that, in spite of failed attempts at air tamponade, a DM detachment and a DAC due to DM perforation following a DALK procedure can resolve spontaneously with good visual outcome.

  4. The azygos anterior cerebral artery bypass: double reimplantation technique for giant anterior communicating artery aneurysms.

    PubMed

    Mirzadeh, Zaman; Sanai, Nader; Lawton, Michael T

    2011-04-01

    The authors introduce the azygos anterior cerebral artery (ACA) bypass as an option for revascularizing distal ACA territories, as part of a strategy to trap giant anterior communicating artery (ACoA) aneurysms. In this procedure, the aneurysm is exposed with an orbitozygomatic-pterional craniotomy and distal ACA vessels are exposed with a bifrontal craniotomy. The uninvolved contralateral A(2) segment of the ACA serves as a donor vessel for a short radial artery graft. The contralateral pericallosal artery (PcaA) and the callosomarginal artery (CmaA) are connected to the graft in the interhemispheric fissure using the double reimplantation technique. Three anastomoses create an azygos system supplying the entire ACA territory, enabling the surgeon to trap the aneurysm incompletely. Retrograde flow from the CmaA supplies the ipsilateral recurrent artery of Heubner, and the aneurysm lumen thromboses. The azygos bypass was successfully performed to treat a 47-year-old woman with a giant, thrombotic ACoA aneurysm supplied by the A(1) segment of the left ACA, with left PcaA and CmaA originating from the aneurysm base. The authors conclude that the azygos ACA bypass is a novel option for revascularizing PcaA and CmaA, as part of the overall treatment of giant ACoA aneurysms.

  5. Outcome of arthroscopic single-bundle anterior cruciate ligament reconstruction: anteromedial portal technique versus transtibial drilling technique.

    PubMed

    Rezazadeh, S; Ettehadi, H; Vosoughi, A R

    2016-04-01

    Controversies exist about the femoral tunnel preparation technique in anterior cruciate ligament (ACL) reconstruction surgeries. The aim of this study was to evaluate mid-term outcomes of transtibial (TT) technique in comparison with anteromedial portal (AMP) one. Demographic data, height, weight, period of time from injury to surgery, and follow-up duration of patients underwent ACL reconstruction using single-bundle hamstring graft by the senior author between 2007 and 2011 were evaluated, retrospectively. Mid-quadriceps circumference difference, passive range of motion of the joint, anterior drawer test, Lachman test, and pivot shift test were assessed for each case. Function of the knee joint was calculated using International Knee Documentation Committee (IKDC), Lysholm, and Tegner scores. Of 50 cases in the AMP group (age 30.6 ± 6.5), 45 were male and of the 44 patients in the TT group (age 30.0 ± 6.5), forty were male. Mean follow-up times in the AMP and TT group were 18.2 months (range 12-84 months) and 25.7 months (range 16-48 months), respectively. No statistically significant difference was found in mid-quadriceps circumference difference (P = 0.861). Also, functional knee scores (P values of IKDC = 0.329, Lysholm score = 0.08, Tegner = 0.504) and stability tests (P values of anterior drawer test = 0.07, Lachman test = 0.486, pivot shift test = 0.348) did not differ statistically between groups. There is no superiority of AMP technique on TT technique in ACL reconstructive surgeries. It could be suggested that performing a well-done technique, either TT or AMP, may be more important than only choosing a technique.

  6. Biomechanical evaluation of knee kinematics after anatomic single- and anatomic double-bundle ACL reconstructions with medial meniscal repair.

    PubMed

    Lorbach, Olaf; Kieb, Matthias; Domnick, Christoph; Herbort, Mirco; Weyers, Imke; Raschke, Michael; Engelhardt, Martin

    2015-09-01

    To evaluate knee laxity after anatomic ACL reconstruction with additional suture repair of a medial meniscus tear. Kinematics of the intact knee were determined in 12 human cadaver specimens in response to a 134-N anterior tibial load (aTT) and a combined rotatory load of 10 Nm valgus and 4 Nm internal tibial rotation (aTTPS) using a robotic/universal force moment sensor testing system. Subsequently, the ACL was resected following the creation of a standardized tear of the medial meniscus, a standard meniscus repair and an ACL reconstruction using an anatomic single-bundle (6) or an anatomic double-bundle technique (6). Knee kinematics were determined following every sub-step. Significant increase of aTT in the ACL-deficient knee was found (p ≤ 0.001) with a further increase in the ACL-deficient knee with additional medial meniscal rupture (p ≤ 0.001). ACL reconstructions significantly decreased aTT compared with the ACL and meniscus-ruptured knee. No significant differences were seen between the intact knee and the ACL-reconstructed knee with additional meniscal repair (p < 0.05). In response to a simulated pivot shift, aTTPS in the intact knee significantly increased in the ACL-deficient knee and meniscus-ruptured knee (p = 0.005). No significant differences in knee kinematics were found between SB as well as DB ACL reconstruction with additional medial meniscal repair compared with the intact knee. Comparison of SB versus DB ACL reconstruction did not reveal any significant differences in a simulated Lachman test or simulated pivot shift test (n.s.). aTT as well as aTTPS significantly increased with ACL deficiency compared with the intact knee; additional medial meniscal rupture further increased aTT. Anatomic ACL reconstruction with medial meniscal repair did not reveal significant differences in knee kinematics compared with the intact knee. Comparison of anatomic SB versus DB ACL reconstruction with additional repair of the medial meniscus did not show

  7. Knee moment and shear force are correlated with femoral tunnel orientation after single-bundle anterior cruciate ligament reconstruction.

    PubMed

    Wang, Hongsheng; Fleischli, James E; Hutchinson, Ian D; Zheng, Naiquan Nigel

    2014-10-01

    Increasing evidence has shown that anatomic single-bundle anterior cruciate ligament reconstruction (ACLR) better restores normal knee kinematics and functionality than nonanatomic ACLR. Whether anatomic reconstruction results in better knee kinetics during daily activities has not been fully investigated. To assess the relationship between femoral tunnel angle and kinetic parameters of the knee joint during walking after single-bundle ACLR and to compare the radiographic and kinetic results of patients who underwent anatomic ACLR with those of patients who underwent nonanatomic ACLR. Controlled laboratory study. Twenty-one patients who underwent unilateral ACLR were recruited, and 20 healthy subjects from a previous study were used as a control group. All surgical procedures were performed by a single surgeon, 11 using the transtibial (TT) technique and 10 using the anteromedial portal (AMP) technique. Femoral tunnel orientation was measured from posterior-to-anterior radiographs. Dynamic knee joint moments and shear forces during gait were evaluated using 3-dimensional motion analysis and inverse dynamics. Relationships between femoral tunnel angles and kinetic results were evaluated via linear regression. Results were compared between 2 ACLR groups and controls using 1-way analysis of variance. Femoral tunnel angle had significant correlations with peak external knee flexion moment and posterior shear force during early stance. The TT group had a significantly smaller (more vertical) mean femoral tunnel angle (19.4° ± 4.1°) than the AMP group (36.4° ± 5.8°). Significant reductions were found in the normalized peak external knee flexion moment (TT, 0.15 ± 0.12 Nm/kg·m; AMP, 0.25 ± 0.12 Nm/kg·m; control, 0.25 ± 0.16 Nm/kg·m) (P = .032) and posterior shear force (TT, 0.64 ± 0.55 N/kg; AMP, 1.10 ± 0.58 N/kg; control, 1.35 ± 0.55 N/kg) (P = .024) in the TT group compared with controls, but not in the AMP group. Moreover, a significantly greater medial

  8. The difference in clinical outcome of single-bundle anterior cruciate ligament reconstructions with and without remnant preservation: A meta-analysis.

    PubMed

    Tie, Kai; Chen, Liaobin; Hu, Dongcai; Wang, Hua

    2016-08-01

    The aim of this study was to compare the clinical performance and complications between an ACL reconstruction with a remnant-preserving single-bundle technique and a standard single-bundle technique. A search was performed of RCTs comparing the clinical outcomes and complications of ACL reconstruction with remnant-preserving and standard single-bundle techniques during October 2014. Relevant data were extracted and CONSORT was used to assess the methodological quality. Stata/SE 12.0 was used to perform a meta-analysis of the clinical outcomes. Six RCTs were included, with a total of 378 patients: 190 in the remnant-preservation technique group and 188 patients in standard-technique group. Assessing anterior stability, no difference was found between the groups for the KT arthrometer, negative rate of Lachman, and the pivot shift test. Assessing functional outcome, there was no significant difference in IKCD scores and grades or Lysholm score. In terms of complications, the percentage of tibial tunnel enlargement in the group of the remnant-preservation technique was significantly lower, despite no significant difference in the incidence of cyclops lesions. The outcome of single-bundle ACL reconstruction with the remnant-preservation technique is similar to that with the standard technique in terms of anterior stability and functional recovery of the knee. Remnant preservation in ACL reconstruction decreases the percentage of tibial tunnel enlargement. Level of evidence is II. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Comparison of femur tunnel aperture location in patients undergoing transtibial and anatomical single-bundle anterior cruciate ligament reconstruction.

    PubMed

    Lee, Dae-Hee; Kim, Hyun-Jung; Ahn, Hyeong-Sik; Bin, Seong-Il

    2016-12-01

    Although three-dimensional computed tomography (3D-CT) has been used to compare femoral tunnel position following transtibial and anatomical anterior cruciate ligament (ACL) reconstruction, no consensus has been reached on which technique results in a more anatomical position because methods of quantifying femoral tunnel position on 3D-CT have not been consistent. This meta-analysis was therefore performed to compare femoral tunnel location following transtibial and anatomical ACL reconstruction, in both the low-to-high and deep-to-shallow directions. This meta-analysis included all studies that used 3D-CT to compare femoral tunnel location, using quadrant or anatomical coordinate axis methods, following transtibial and anatomical (AM portal or OI) single-bundle ACL reconstruction. Six studies were included in the meta-analysis. Femoral tunnel location was 18 % higher in the low-to-high direction, but was not significant in the deep-to-shallow direction, using the transtibial technique than the anatomical methods, when measured using the anatomical coordinate axis method. When measured using the quadrant method, however, femoral tunnel positions were significantly higher (21 %) and shallower (6 %) with transtibial than anatomical methods of ACL reconstruction. The anatomical ACL reconstruction techniques led to a lower femoral tunnel aperture location than the transtibial technique, suggesting the superiority of anatomical techniques for creating new femoral tunnels during revision ACL reconstruction in femoral tunnel aperture location in the low-to-high direction. However, the mean difference in the deep-to-shallow direction differed by method of measurement. Meta-analysis, Level II.

  10. Assessment of normal ACL double bundle anatomy in standard viewing planes by magnetic resonance imaging.

    PubMed

    Starman, James S; Vanbeek, Corinne; Armfield, Derek R; Sahasrabudhe, Amit; Baker, Champ L; Irrgang, James J; Fu, Freddie H

    2007-05-01

    Anatomical studies show that the native ACL consists of two distinct functional bundles, termed the anteromedial (AM) and posterolateral (PL) bundles. The utility of using routine magnetic resonance imaging (MRI) to distinguish the individual bundles of the ACL has not been evaluated. The purpose of this study was to evaluate the intra- and inter-observer agreement for assessment of the AM and PL bundles using MRI in the axial, coronal, and sagittal viewing planes. We identified a series of patients seen in the senior author's clinic during a 16-month period. Images were independently evaluated in blinded fashion at two separate time points by a musculoskeletal radiologist and two orthopaedic residents. The AM bundle was detected in most planes of view with high frequency and reliability, while detection of the PL bundle was less frequent and had a lower associated reliability. Our results indicate that it is difficult to reliably detect both the AM and PL bundles using a low-field strength magnet with standard planes of view. It has been demonstrated that the ACL may be imaged effectively in planes that are based on the natural course of the ligament, and it is likely that this will also facilitate visualization of the individual AM and PL bundles. The use of additional oblique planes of view offers a potential approach for improved evaluation of the ACL, even with low field strength magnets. Future work in this area may assist in the pre-operative assessment of isolated AM or PL bundle injuries, facilitating a more anatomic approach to ACL reconstruction.

  11. Femoral and Tibial Tunnel Diameter and Bioabsorbable Screw Findings After Double-Bundle ACL Reconstruction in 5-Year Clinical and MRI Follow-up

    PubMed Central

    Kiekara, Tommi; Paakkala, Antti; Suomalainen, Piia; Huhtala, Heini; Järvelä, Timo

    2017-01-01

    Background: Tunnel enlargement is frequently seen in short-term follow-up after anterior cruciate ligament reconstruction (ACLR). According to new evidence, tunnel enlargement may be followed by tunnel narrowing, but the long-term evolution of the tunnels is currently unknown. Hypothesis/Purpose: The hypothesis was that tunnel enlargement is followed by tunnel narrowing caused by ossification as seen in follow-up using magnetic resonance imaging (MRI). The purpose of this study was to evaluate the ossification pattern of the tunnels, the communication of the 2 femoral and 2 tibial tunnels, and screw absorption findings in MRI. Study Design: Case series; Level of evidence, 4. Methods: Thirty-one patients underwent anatomic double-bundle ACLR with hamstring grafts and bioabsorbable interference screw fixation and were followed with MRI and clinical evaluation at 2 and 5 years postoperatively. Results: The mean tunnel enlargement at 2 years was 58% and reduced to 46% at 5 years. Tunnel ossification resulted in evenly narrowed tunnels in 44%, in conical tunnels in 48%, and fully ossified tunnels in 8%. Tunnel communication increased from 13% to 23% in the femur and from 19% to 23% in the tibia between 2 and 5 years and was not associated with knee laxity. At 5 years, 54% of the screws were not visible, with 35% of the screws replaced by a cyst and 19% fully ossified. Tunnel cysts were not associated with worse patient-reported outcomes or knee laxity. Patients with a tibial anteromedial tunnel cyst had higher Lysholm scores than patients without a cyst (93 and 84, P = .03). Conclusion: Tunnel enlargement was followed by tunnel narrowing in 5-year follow-up after double-bundle ACLR. Tunnel communication and tunnel cysts were frequent MRI findings and not associated with adverse clinical evaluation results. PMID:28203605

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

    PubMed Central

    Zeng, Xiangbing; Prehm, Marko

    2016-01-01

    Abstract A quaternary amphiphile with swallow‐tail side groups displays a new bicontinuous thermotropic cubic phase with symmetry Pn 3‾ 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

  13. Reconstruction of compound loss of lateral malleolus and lateral ankle ligaments with double-bundle Achilles tendon-bone allograft.

    PubMed

    Ko, Dukhwan; Jung, Hong-Geun; Kim, Hyeung-June; Cha, Seung-Han; Nam, Kyoung-Mo

    2014-01-01

    Open ankle fracture, including compound loss of the lateral malleolus, lateral ankle ligaments, and overlying skin, is a severe injury and can result in ankle instability and permanent disability. Treatment of this injury is challenging and requires bone grafting and soft tissue reconstruction. In the present report, we describe a unique reconstruction technique for compound loss of the lateral malleolus, lateral ankle ligaments, and the overlying skin using a double-bundle Achilles tendon-bone allograft combined with a reverse sural fasciocutaneous flap. The patient obtained a stable ankle with nearly full range of motion and displayed satisfactory function during the follow-up period.

  14. Human medial forebrain bundle (MFB) and anterior thalamic radiation (ATR): imaging of two major subcortical pathways and the dynamic balance of opposite affects in understanding depression.

    PubMed

    Coenen, Volker A; Panksepp, Jaak; Hurwitz, Trevor A; Urbach, Horst; Mädler, Burkhard

    2012-01-01

    The medial forebrain bundle (MFB), a key structure of reward-seeking circuitry, remains inadequately characterized in humans despite its vast importance for emotional processing and development of addictions and depression. Using Diffusion Tensor Imaging Fiber Tracking (DTI FT) the authors describe potential converging ascending and descending MFB and anterior thalamic radiation (ATR) that may mediate major brain reward-seeking and punishment functions. Authors highlight novel connectivity, such as supero-lateral-branch MFB and ATR convergence, caudally as well as rostrally, in the anterior limb of the internal capsule and medial prefrontal cortex. These anatomical convergences may sustain a dynamic equilibrium between positive and negative affective states in human mood-regulation and its various disorders, especially evident in addictions and depression.

  15. Left ventricular regional contraction abnormalities by echocardiographic speckle tracking in combined right bundle branch with left anterior fascicular block compared to left bundle branch block.

    PubMed

    Leeters, Irene P M; Davis, Ashlee; Zusterzeel, Robbert; Atwater, Brett; Risum, Niels; Søgaard, Peter; Klem, Igor; Nijveldt, Robin; Wagner, Galen S; Gorgels, Anton P M; Kisslo, Joseph

    2016-01-01

    In contrast to LBBB patients less is known about patients with RBBB+LAFB regarding LV contractile abnormalities and the potential role of CRT. This study investigated whether patients with RBBB+LAFB morphology have echocardiographic mechanical strain abnormalities between the inferior and anterior LV walls, similar to abnormalities between septal and lateral walls in LBBB. Ten healthy volunteers with no-BBB, 28 LBBB and 28 RBBB+LAFB heart failure patients were included in this retrospective study. Two-dimensional regional-strains were obtained by speckle-tracking. Scar was assessed by CMR. Response on echo was defined as normal, classical, borderline or other pattern. The number of classical patterns in LBBB was significantly higher than in RBBB+LAFB and no-BBB groups (p<0.001 for both). Contrary, the RBBB+LAFB group showed a significantly higher number of borderline patterns compared to other groups (LBBB: p=0.042, no-block: p=0.012). In addition, RBBB+LAFB patients had more scar than LBBB patients (9.9% vs 3.4%, p=0.041), and the average amount of scar in each wall was also higher in RBBB+LAFB (<5% in LBBB and <16% in RBBB+LAFB). Patients with RBBB+LAFB on ECG and clinical HF demonstrate echocardiographic wall motion abnormalities between inferior and anterior LV walls, similar to abnormalities found between septal and lateral LV walls in patients with LBBB and HF. Fewer patients with RBBB+LAFB showed a classical pattern of opposing wall motion compared to LBBB. Factors that might alter strain patterns in RBBB+LAFB, including the detailed presence or absence of LV scar and coexisting block of the central fascicle, should be assessed in future studies. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Polarisation of Graded Bundles

    NASA Astrophysics Data System (ADS)

    Bruce, Andrew James; Grabowski, Janusz; Rotkiewicz, Mikołaj

    2016-11-01

    We construct the full linearisation functor which takes a graded bundle of degree k (a particular kind of graded manifold) and produces a k-fold vector bundle. We fully characterise the image of the full linearisation functor and show that we obtain a subcategory of k-fold vector bundles consisting of symmetric k-fold vector bundles equipped with a family of morphisms indexed by the symmetric group S_k. Interestingly, for the degree 2 case this additional structure gives rise to the notion of a symplectical double vector bundle, which is the skew-symmetric analogue of a metric double vector bundle. We also discuss the related case of fully linearising N-manifolds, and how one can use the full linearisation functor to ''superise'' a graded bundle.

  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. Double bilobed radial forearm free flap for anterior tongue and floor-of-mouth reconstruction.

    PubMed

    Ko, Alvin B; Lavertu, Pierre; Rezaee, Rod P

    2010-04-01

    We describe what is, to the best of our knowledge, the first use of a double bilobed radial forearm free flap in reconstructive surgery of the tongue and floor of the mouth following bilateral tumor resection. Our patient was a 78-year-old man who had experienced tumor recurrence in the anterior floor of the mouth after previous resection and radiotherapy. Eleven weeks postoperatively, the patient could extend his tongue to his hard palate and past his mandibular alveolus anteriorly. Within 6 months, he was able to tolerate an oral diet of soft food and exhibited understandable speech quality. Although the use of a single bilobed radial forearm flap is widely used after hemiglossectomy, our double bilobed modification extends this technique to anterior tongue and floor-of-mouth defects. This technique provides adequate bulk while allowing for depth of a ventral sulcus that will minimize tethering of the tongue and reduce oral incompetence. We recommend that this technique be included in the armamentarium of any reconstructive head and neck cancer surgeon.

  19. An anterior mediastinal mass: delayed airway compression and using a double lumen tube for airway patency.

    PubMed

    Lee, Jeounghyuk; Rim, Yong Chul; In, Junyong

    2014-06-01

    Perioperative management of patients with an anterior mediastinal mass is difficult. We present a 35-year-old woman who showed delayed compression of the carina and left main bronchus despite no preoperative respiratory signs, symptoms, or radiologic findings due to an anterior mediastinal mass and uneventful stepwise induction of general anesthesia. Even use of a fiberoptic bronchoscope (FB) after induction of anesthesia was not helpful to predict delayed compression of the airway. Therefore, the anesthesiologist and the cardiothoracic surgeon must prepare for unexpected delayed compression of the airway, even in low risk patients who are asymptomatic or mildly symptomatic without postural symptoms or radiographic evidence of significant compression of structures. We also describe successful management for the compressed carina and left main bronchus with a double lumen tube (DLT) as a stent during surgery. FB guided DLT intubation is a possible solution to maintain airway patency.

  20. Septal and anterior reverse mismatch of myocardial perfusion and metabolism in patients with coronary artery disease and left bundle branch block.

    PubMed

    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

    2015-05-01

    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.

  1. [Double fulguration of the bundles of His and Kent for recurrent tachycardia in Wolff-Parkinson-White syndrome].

    PubMed

    Leclercq, J F; Maison-Blanche, P; Cauchemez, B; Bizot, J; Coumel, P; Slama, R

    1986-01-01

    A 59 year old patient with a left postero-septal Kent bundle had daily attacks of reciprocating tachycardia resistant to anti-arrhythmic therapy and was referred for catheter ablation. Kent bundle activity was recorded in the proximal part of the coronary sinus. An endocavitary electric shock delivered at this site suppressed conduction through the Kent bundle for several minutes. Catheter ablation of the His bundle (2 X 200 joules) was then attempted suppressing anterograde conduction for 2 days, after which conduction was reestablished and the reciprocating tachycardia recurred. A second session of catheter ablation was carried out and 2 X 200 joules shocks were delivered in the coronary sinus and 4 to the Bundle of His. Complete anterograde and retrograde atrioventricular block was obtained. Two weeks later, the patient recovered anterograde conduction through the accessory pathway. Retrograde conduction through the Kent bundle was decremental, RP' lengthening with increasing heart rate. Conduction was detected in the His bundle but was insufficient to give rise to reciprocating rhythm. After one year's follow-up the patient was asymptomatic without treatment. Catheter ablation of physiological or accessory conduction pathways provides a valuable alternative to surgical treatment of pre-excitation pathways in the WPW syndrome resistant to medical therapy.

  2. Arthroscopic single-bundle anterior cruciate ligament reconstruction with six-strand hamstring tendon allograft versus bone-patellar tendon-bone allograft.

    PubMed

    Dai, Chengliang; Wang, Fei; Wang, Xiaomeng; Wang, Ruipeng; Wang, Shengjie; Tang, Shiyu

    2016-09-01

    The aim of this study was to compare the clinical outcomes of arthroscopic single-bundle anterior cruciate ligament (ACL) reconstruction with six-strand hamstring tendon (HT) allograft versus bone-patellar tendon-bone (BPTB) allograft. The prospective randomized controlled trial was included 129 patients. Sixty-nine patients received reconstruction with six-strand HT allografts (HT group), whereas 60 patients with BPTB allografts (BPTB group). Outcome assessment included re-rupture findings, International Knee Documentation Committee (IKDC) scores, Lysholm scores, KT-1000 arthrometer, Lachman test, pivot-shift test, range of motion (ROM) and single-leg hop test. At a mean follow-up of 52 months, 113 patients (HT group, 61 patients; BPTB group, 52 patients) completed a minimum 4-year follow-up. Four patients in HT group and six in BPTB group experienced ACL re-rupture (6.2 vs. 10.3 %) and received revision surgery. Significant between-group differences were observed in KT-1000 outcomes and pivot-shift test 1 (1.2 ± 1.5 vs. 1.8 ± 1.3, p = 0.025; positive rate 6.5 vs. 18.9 %, p = 0.036), 2 (1.1 ± 1.4 vs. 1.6 ± 1.2, p = 0.044; 8.1 vs. 20.7 %, p = 0.039), 4 (1.1 ± 1.5 vs. 1.7 ± 1.4, p = 0.031; 9.7 vs. 25 %, p = 0.012) years postoperatively. The outcomes between the two groups were comparable in terms of IKDC scores, Lysholm scores, Lachman test, ROM and single-leg hop test. Six-strand HT allograft achieved superior anteroposterior and rotational stability after single-bundle ACL reconstruction. It is a reasonable graft substitute for ACL reconstruction. II.

  3. A comparison of dynamic rotational knee instability between anatomic single-bundle and over-the-top anterior cruciate ligament reconstruction using triaxial accelerometry.

    PubMed

    Asai, Shigehiro; Maeyama, Akira; Hoshino, Yuichi; Goto, Bunsei; Celentano, Umberto; Moriyama, Shigeaki; Smolinski, Patrick; Fu, Freddie H

    2014-05-01

    Recently, single-bundle (SB) anterior cruciate ligament (ACL) reconstruction has been advanced by the anatomic concept, but the biomechanical outcome of the anatomic method has not been fully investigated, especially for rotational instability. Anatomic SB and the single over-the-top procedures are the treatment of choice for primary cases and revision or skeletally immature cases, respectively. The purpose of this study was to investigate the dynamic rotational instability of anatomic SB and over-the-top reconstruction during a pivot shift test using triaxial accelerometry. Eight fresh frozen human cadaveric knees were used in this study. Rotational instability measurement was conducted during a pivot shift test by the use of a triaxial accelerometer attached to the tibia. The tests were performed in the ACL-intact, ACL-deficient and ACL-reconstructed knees with two different procedures (anatomic SB and over-the-top). The acceleration in three directions and the magnitude of acceleration were measured to evaluate rotational instability and compare between four different knee states. The overall magnitude of acceleration was significantly different (P < 0.01) between the ACL-intact knees and the ACL-deficient knees. Both anatomic SB and over-the-top ACL reconstruction significantly reduced the overall magnitude of acceleration compared to the ACL-deficient knees, but still had larger accelerations compared to the ACL-intact knees. There was no significant difference for the overall magnitude of acceleration between anatomic SB and over-the-top reconstruction procedure. Over-the-top reconstruction provides comparable result to anatomic SB reconstruction in terms of controlling the dynamic rotational stability. Over-the-top reconstruction might be one of the options for revision cases and in skeletally immature patients.

  4. Long-term Evaluation of a Modified Double Staple Technique for Low Anterior Resection.

    PubMed

    Illuminati, G; Carboni, F; Ceccanei, G; Pacilè, M A; Pizzardi, G; Palumbo, P; Vietri, F

    2014-01-01

    When performing low anterior resection for rectal cancer with the double staple technique, -closing the rectum with a linear stapler in the abdomen can be challenging, especially when dealing with a narrow pelvis. For such instances we proposed to modify this technique by pulling the rectal stump through the anus, doing an extra-anal resection of the tumor and linear suture of the rectal stump, before performing a standard, stapled colorectal anastomosis. The purpose of this study was to assess the adequacy of this modification of the double staple technique. Retrospective review of 108 patients undergoing a stapled, low colorectal or coloanal anastomosis, after -eversion, extra-anal resection of the tumor and linear closure of the rectal stump for colorectal cancer, from January 1990 to December 2012. Operative mortality was 0.9%. Fourteen patients (13%) presented early, surgery-related complications -consisting of 7 anastomotic leaks, 5 wound infections, 1 ureteral lesion, and 1 peristomal abscess. Late complications related to surgery included 5 incisional hernias (4.6%), 4 anastomotic strictures (3.7%), 4 neurogenic bladders (3.7%) and 2 fecal incontinences (1.8%). The incidence of local disease recurrence was 10%. Surgical and oncological results validate the proposed modification of the double staple technique, when facing difficulties in suturing the rectum from the abdomen. Copyright© Acta Chirurgica Belgica.

  5. Double-Barrel Remplissage: An Arthroscopic All-Intra-articular Technique Using the Double-Barrel Knot for Anterior Shoulder Instability.

    PubMed

    Bhatia, Deepak N

    2015-02-01

    The arthroscopic remplissage procedure is an effective addition to a standard anterior repair in traumatic anterior shoulder instability associated with large humeral defects. The double-barrel remplissage is an all-intra-articular technique that uses a double-pulley, sliding, and self-retaining knot mechanism called the double-barrel knot. A 70° arthroscope (posterior portal) is necessary for adequate visualization of the humeral defect and the rotator cuff. Trans-tendon anchors (single or double loaded) are inserted into the superior and inferior aspects of the humeral defect through a cannula that is placed posterior to the infraspinatus. Placement of anchors is facilitated by insertion of a guidewire, as well as an anchor sleeve that is threaded over it. The double-barrel knot is formed using the anchors as a double-pulley system, and the knot is tensioned after the anterior repair is complete. Intra-articular visualization confirms adequate approximation and compression of the infraspinatus tendon and capsule into the defect. Advantages include an increased surface area (footprint) for healing and ease of knotting without the necessity for additional subacromial dissection.

  6. Volumetric Damage to the Femoral Physis During Double-Bundle Posterior Cruciate Ligament Reconstruction: A Magnetic Resonance Imaging Computer Modeling Study.

    PubMed

    Shea, Kevin G; Grimm, Nathan L; Nichols, Francesca R; Jacobs, John C

    2015-06-01

    The purpose of this study was to use computer models to evaluate the volume of femoral physeal disruption in double-bundle posterior cruciate ligament (PCL) reconstruction in patients with open physes. Ten skeletally immature patients (6 girls and 4 boys) were selected for this study. The magnetic resonance imaging scans of each patient were converted into a 3-dimensional model using computer-aided design/computer-aided manufacturing software. The software allowed the users to differentiate the epiphyseal, physeal, and metaphyseal tissues. This allowed for quantification of volume removed of each tissue type. Furthermore, we used the 3-dimensional models to simulate an anatomic double-bundle technique using 6-, 7-, 8-, and 9-mm-diameter tunnels. The software method reflects an inside-out drilling technique. For drill holes of all diameters, the posteromedial tunnels exited the knee inferior to the physis, thus avoiding physeal damage. In contrast, all the anterolateral tunnels perforated the physis. The results for the percent of total physis removed are as follows: 6-mm tunnel, 1.79% ± 0.99%; 7-mm tunnel, 2.23% ± 1.19%; 8-mm tunnel, 3.00% ± 1.54%; and 9-mm tunnel, 3.84% ± 1.73%. This computer modeling simulation of double-bundle PCL reconstruction in skeletally immature knees found that the posteromedial tunnel avoided disruption of the distal femoral physis. In contrast, the anterolateral tunnel did disrupt the physis with all drill hole sizes (6 to 9 mm), but all had a less than 4% volume of total physis removed. A clear understanding of the drill hole position may reduce the volume of physeal injury during double-bundle PCL reconstruction. This study shows that physeal disruption of less than the experimental 7% threshold that has been shown to cause physeal arrest may not cause arrest, but this is still speculative. Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  7. Femoral and tibial graft tunnel parameters after transtibial, anteromedial portal, and outside-in single-bundle anterior cruciate ligament reconstruction.

    PubMed

    Osti, Michael; Krawinkel, Alessa; Ostermann, Michael; Hoffelner, Thomas; Benedetto, Karl Peter

    2015-09-01

    Anatomic graft tunnel placement is recommended in anterior cruciate ligament (ACL) reconstruction to restore knee joint stability and function. Transtibial (TT), anteromedial portal (AMP), and outside-in (OI) retrograde drilling surgical techniques have been described for tibial and femoral bone tunnel preparation. The purpose of this study was to evaluate the bone tunnel parameters and compare the ability of 3 different surgical techniques to achieve placement of the ACL femoral and tibial bone tunnels at the center of the native ACL femoral and tibial attachment sites. The hypothesis was that tunnel placement using an AMP or OI technique would result in optimized tunnel parameters and more closely reconstruct the center of the native ACL femoral attachment site. Cohort study; Level of evidence, 3. The study population consisted of 100 patients undergoing anatomic single-bundle ACL reconstruction using multiple-stranded hamstring tendon grafts. In group 1 (n = 36), the femoral tunnel was drilled using a TT surgical technique; in group 2 (n = 32), the femoral tunnel was drilled through an AMP; and in group 3 (n = 32), the femoral tunnel was created by use of an OI technique with retrograde drilling. Computed tomography (CT) scans were obtained postoperatively, and characteristics of femoral and tibial tunnel apertures were correlated to femoral and tibial measurement grid systems. The position of the resulting tibial and femoral bone tunnels for each group was compared with the center of the native ACL attachment sites. There were statistically significant differences (P < .05) for the ACL femoral tunnel between the 3 groups with respect to intercondylar height, total tunnel length, graft fixation length, tunnel axis, and tunnel entry angle. Statistically significant differences (P < .05) were found for the ACL tibial tunnel with respect to anteroposterior tunnel position and sagittal tunnel axis between the TT and both the OI and AMP techniques. The OI surgical

  8. Anatomic Anterolateral Ligament Reconstruction Improves Postoperative Clinical Outcomes Combined with Anatomic Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Qiu, Man; Zhou, Aiguo; Zhang, Jian; Jiang, Dianming

    2016-01-01

    A significant cohort of patients is plagued by postoperative rotational instability after the anatomic anterior cruciate ligament (ACL) reconstruction surgery. Anatomic anterolateral ligament (ALL) reconstruction was performed in this study with the aim to assess the clinical role of ALL in knee’s stability and joint functions. Sixty patients were recruited and divided into three groups to perform the operations of anatomic single-bundle ACL reconstruction, anatomic double-bundle ACL reconstruction, and anatomic single-bundle ACL reconstruction + anterolateral ligament reconstruction, respectively. And then postoperative knee’s stability and joint functions were evaluated to compare the clinical outcomes among the three different kind of operations. The postoperative knee’s stability and joint functions of the anatomic double-bundle ACL reconstruction group and the anatomic single-bundle ACL reconstruction + ALL reconstruction group were better than the anatomic single-bundle ACL reconstruction group. No significant difference was observed between the anatomic double-bundle ACL reconstruction group and the anatomic single-bundle ACL reconstruction + ALL reconstruction group. The anatomic anterolateral ligament reconstruction could improve the clinical outcomes after patients performed the anatomic single-bundle anterior cruciate ligament reconstruction. This indicates that the anterolateral ligament plays a crucial role in knee’s stability and joint function, especially the rotational stability. Key points Anatomic anterolateral ligament reconstruction combined with anatomic anterior cruciate ligament reconstruction was performed to treat the patients with ACL rupture. Compared to the anatomic single-bundle ACL reconstruction group, the anatomic single-bundle ACL reconstruction + ALL reconstruction group achieve a better clinical outcomes. The results suggest that the anterolateral ligament plays a crucial role in knee’s stability and joint function

  9. Kinematic Analysis of Five Different Anterior Cruciate Ligament Reconstruction Techniques.

    PubMed

    Gadikota, Hemanth R; Hosseini, Ali; Asnis, Peter; Li, Guoan

    2015-06-01

    Several anatomical anterior cruciate ligament (ACL) reconstruction techniques have been proposed to restore normal joint kinematics. However, the relative superiorities of these techniques with one another and traditional single-bundle reconstructions are unclear. Kinematic responses of five previously reported reconstruction techniques (single-bundle reconstruction using a bone-patellar tendon-bone graft [SBR-BPTB], single-bundle reconstruction using a hamstring tendon graft [SBR-HST], single-tunnel double-bundle reconstruction using a hamstring tendon graft [STDBR-HST], anatomical single-tunnel reconstruction using a hamstring tendon graft [ASTR-HST], and a double-tunnel double-bundle reconstruction using a hamstring tendon graft [DBR-HST]) were systematically analyzed. The knee kinematics were determined under anterior tibial load (134 N) and simulated quadriceps load (400 N) at 0°, 15°, 30°, 60°, and 90° of flexion using a robotic testing system. Anterior joint stability under anterior tibial load was qualified as normal for ASTR-HST and DBR-HST and nearly normal for SBR-BPTB, SBR-HST, and STDBR-HST as per the International Knee Documentation Committee knee examination form categorization. The analysis of this study also demonstrated that SBR-BPTB, STDBR-HST, ASTR-HST, and DBR-HST restored the anterior joint stability to normal condition while the SBR-HST resulted in a nearly normal anterior joint stability under the action of simulated quadriceps load. The medial-lateral translations were restored to normal level by all the reconstructions. The internal tibial rotations under the simulated muscle load were over-constrained by all the reconstruction techniques, and more so by the DBR-HST. All five ACL reconstruction techniques could provide either normal or nearly normal anterior joint stability; however, the techniques over-constrained internal tibial rotation under the simulated quadriceps load.

  10. Nonarteritic anterior ischemic optic neuropathy and double thrombophilic defect: a new observation.

    PubMed

    Papageorgiou, Eleni; Karamagkiolis, Spyridon; Dimera, Vasiliki

    2012-01-01

    WE REPORT THE FIRST CASE OF NONARTERITIC ANTERIOR ISCHEMIC NEUROPATHY (NAION) ASSOCIATED WITH DOUBLE THROMBOPHILIA: protein S deficiency and prothrombin G20210A mutation. A 58-year-old man is presented including the clinical and laboratory findings, cardiovascular profile and thrombophilia screening. The patient presented with 3/10 vision and an inferior altitudinal defect in the right eye. Funduscopic examination of the right eye revealed a hyperemic optic disk with blurred superior optic disk border and sectoral nerve fiber layer edema. Complete blood count, erythrocyte sedimentation rate and C-reactive protein were normal, suggesting a NAION. A workup of cardiovascular risk factors revealed hyperlipidemia, arterial hypertension and high-risk asymptomatic coronary artery disease. Due to the family history of deep vein thrombosis in the patient's daughter, a thrombophilia screening was additionally performed. The results revealed a double thrombophilic defect, namely congenital protein S deficiency and heterozygosity for prothrombin G20210A mutation, which were also identified in the patient's daughter. Anticoagulant warfarin therapy was initiated and the patient underwent a triple bypass surgery. At three-month follow-up, the right optic disk edema had resolved, leaving a pale superior optic nerve head. Visual acuity in the right eye had slightly improved to 4/10; however, the dense inferior altitudinal field defect had remained unchanged. The patient is currently treated with warfarin, atorvastatin, irbesartan and metoprolol. This case suggests that the first line of investigation in all patients with NAION involves assessment of cardiovascular risk factors. However, careful history taking will identify NAION patients who are eligible for additional thrombophilia screening: young patients without vasculopathic risk factors, bilateral or recurrent NAION, idiopathic or recurrent venous thromboembolism (VTE), positive family history of VTE, and VTE in young age or

  11. Anterior pallidal deep brain stimulation for Tourette's syndrome: a randomised, double-blind, controlled trial.

    PubMed

    Welter, Marie-Laure; Houeto, Jean-Luc; Thobois, Stéphane; Bataille, Benoit; Guenot, Marc; Worbe, Yulia; Hartmann, Andreas; Czernecki, Virginie; Bardinet, Eric; Yelnik, Jerome; du Montcel, Sophie Tezenas; Agid, Yves; Vidailhet, Marie; Cornu, Philippe; Tanguy, Audrey; Ansquer, Solène; Jaafari, Nematollah; Poulet, Emmanuel; Serra, Giulia; Burbaud, Pierre; Cuny, Emmanuel; Aouizerate, Bruno; Pollak, Pierre; Chabardes, Stephan; Polosan, Mircea; Borg, Michel; Fontaine, Denys; Giordana, Bruno; Raoul, Sylvie; Rouaud, Tiphaine; Sauvaget, Anne; Jalenques, Isabelle; Karachi, Carine; Mallet, Luc

    2017-08-01

    Deep brain stimulation (DBS) has been proposed to treat patients with severe Tourette's syndrome, and open-label trials and two small double-blind trials have tested DBS of the posterior and the anterior internal globus pallidus (aGPi). We aimed to specifically assess the efficacy of aGPi DBS for severe Tourette's syndrome. In this randomised, double-blind, controlled trial, we recruited patients aged 18-60 years with severe and medically refractory Tourette's syndrome from eight hospitals specialised in movement disorders in France. Enrolled patients received surgery to implant bilateral electrodes for aGPi DBS; 3 months later they were randomly assigned (1:1 ratio with a block size of eight; computer-generated pairwise randomisation according to order of enrolment) to receive either active or sham stimulation for the subsequent 3 months in a double-blind fashion. All patients then received open-label active stimulation for the subsequent 6 months. Patients and clinicians assessing outcomes were masked to treatment allocation; an unmasked clinician was responsible for stimulation parameter programming, with intensity set below the side-effect threshold. The primary endpoint was difference in Yale Global Tic Severity Scale (YGTSS) score between the beginning and end of the 3 month double-blind period, as assessed with a Mann-Whitney-Wilcoxon test in all randomly allocated patients who received active or sham stimulation during the double-blind period. We assessed safety in all patients who were enrolled and received surgery for aGPi DBS. This trial is registered with ClinicalTrials.gov, number NCT00478842. Between Dec 6, 2007, and Dec 13, 2012, we enrolled 19 patients. We randomly assigned 17 (89%) patients, with 16 completing blinded assessments (seven [44%] in the active stimulation group and nine [56%] in the sham stimulation group). We noted no significant difference in YGTSS score change between the beginning and the end of the 3 month double-blind period

  12. The intentional oblique transection double stapling technique in anterior resection for rectal cancer.

    PubMed

    Kuramoto, Masafumi; Ikeshima, Satoshi; Yamamoto, Kenichiro; Morita, Keisuke; Uchihara, Tomoyuki; Itouyama, Rumi; Yoshimatsu, Shinichi; Shimada, Shinya; Baba, Hideo

    2017-04-01

    The double stapling technique (DST) is an intestinal reconstruction technique that has been widely adopted in anterior resection (AR) for rectal cancer. However, anastomotic leakage (AL) after the operation remains a major concern for colorectal surgeons. The sharp-angled corner of the remnant rectum that is often created by the ordinary DST can be a risk factor for AL. We have developed a new method of performing intentional oblique transection DST (IOT-DST). Using this technique, the anal side of the rectum is intentionally obliquely transected with linear staplers, and the area of the sharp-angled edge is totally punched out with a circular stapler. Between September 2015 and March 2016, we used the IOT-DST technique in the treatment of 15 consecutive rectal cancer patients and experienced no anastomosis-related complications, including leakage and stenosis. IOT-DST is easy to use and less stressful to perform than other techniques. IOT-DST has the potential to become the standard technique for AR in rectal cancer surgery.

  13. Relationships Between Tibiofemoral Contact Forces and Cartilage Morphology at 2 to 3 Years After Single-Bundle Hamstring Anterior Cruciate Ligament Reconstruction and in Healthy Knees.

    PubMed

    Saxby, David John; Bryant, Adam L; Wang, Xinyang; Modenese, Luca; Gerus, Pauline; Konrath, Jason M; Bennell, Kim L; Fortin, Karine; Wrigley, Tim; Cicuttini, Flavia M; Vertullo, Christopher J; Feller, Julian A; Whitehead, Tim; Gallie, Price; Lloyd, David G

    2017-08-01

    Prevention of knee osteoarthritis (OA) following anterior cruciate ligament (ACL) rupture and reconstruction is vital. Risk of postreconstruction knee OA is markedly increased by concurrent meniscal injury. It is unclear whether reconstruction results in normal relationships between tibiofemoral contact forces and cartilage morphology and whether meniscal injury modulates these relationships. Since patients with isolated reconstructions (ie, without meniscal injury) are at lower risk for knee OA, we predicted that relationships between tibiofemoral contact forces and cartilage morphology would be similar to those of normal, healthy knees 2 to 3 years postreconstruction. In knees with meniscal injuries, these relationships would be similar to those reported in patients with knee OA, reflecting early degenerative changes. Cross-sectional study; Level of evidence, 3. Three groups were examined: (1) 62 patients who received single-bundle hamstring reconstruction with an intact, uninjured meniscus (mean age, 29.8 ± 6.4 years; mean weight, 74.9 ± 13.3 kg); (2) 38 patients with similar reconstruction with additional meniscal injury (ie, tear, repair) or partial resection (mean age, 30.6 ± 6.6 years; mean weight, 83.3 ± 14.3 kg); and (3) 30 ligament-normal, healthy individuals (mean age, 28.3 ± 5.2 years; mean weight, 74.9 ± 14.9 kg) serving as controls. All patients underwent magnetic resonance imaging to measure the medial and lateral tibial articular cartilage morphology (volumes and thicknesses). An electromyography-driven neuromusculoskeletal model determined medial and lateral tibiofemoral contact forces during walking. General linear models were used to assess relationships between tibiofemoral contact forces and cartilage morphology. In control knees, cartilage was thicker compared with that of isolated and meniscal-injured ACL-reconstructed knees, while greater contact forces were related to both greater tibial cartilage volumes (medial: R(2) = 0.43, β = 0

  14. Relationships Between Tibiofemoral Contact Forces and Cartilage Morphology at 2 to 3 Years After Single-Bundle Hamstring Anterior Cruciate Ligament Reconstruction and in Healthy Knees

    PubMed Central

    Saxby, David John; Bryant, Adam L.; Wang, Xinyang; Modenese, Luca; Gerus, Pauline; Konrath, Jason M.; Bennell, Kim L.; Fortin, Karine; Wrigley, Tim; Cicuttini, Flavia M.; Vertullo, Christopher J.; Feller, Julian A.; Whitehead, Tim; Gallie, Price; Lloyd, David G.

    2017-01-01

    Background: Prevention of knee osteoarthritis (OA) following anterior cruciate ligament (ACL) rupture and reconstruction is vital. Risk of postreconstruction knee OA is markedly increased by concurrent meniscal injury. It is unclear whether reconstruction results in normal relationships between tibiofemoral contact forces and cartilage morphology and whether meniscal injury modulates these relationships. Hypotheses: Since patients with isolated reconstructions (ie, without meniscal injury) are at lower risk for knee OA, we predicted that relationships between tibiofemoral contact forces and cartilage morphology would be similar to those of normal, healthy knees 2 to 3 years postreconstruction. In knees with meniscal injuries, these relationships would be similar to those reported in patients with knee OA, reflecting early degenerative changes. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Three groups were examined: (1) 62 patients who received single-bundle hamstring reconstruction with an intact, uninjured meniscus (mean age, 29.8 ± 6.4 years; mean weight, 74.9 ± 13.3 kg); (2) 38 patients with similar reconstruction with additional meniscal injury (ie, tear, repair) or partial resection (mean age, 30.6 ± 6.6 years; mean weight, 83.3 ± 14.3 kg); and (3) 30 ligament-normal, healthy individuals (mean age, 28.3 ± 5.2 years; mean weight, 74.9 ± 14.9 kg) serving as controls. All patients underwent magnetic resonance imaging to measure the medial and lateral tibial articular cartilage morphology (volumes and thicknesses). An electromyography-driven neuromusculoskeletal model determined medial and lateral tibiofemoral contact forces during walking. General linear models were used to assess relationships between tibiofemoral contact forces and cartilage morphology. Results: In control knees, cartilage was thicker compared with that of isolated and meniscal-injured ACL-reconstructed knees, while greater contact forces were related to both

  15. Three-Dimensional Reconstruction Computed Tomography Evaluation of Tunnel Location during Single-Bundle Anterior Cruciate Ligament Reconstruction: A Comparison of Transtibial and 2-Incision Tibial Tunnel-Independent Techniques

    PubMed Central

    Ahn, Jin Hwan; Ko, Chun-Suk; Ko, Taeg Su; Kim, Jang Hwan

    2013-01-01

    Background Anatomic tunnel positioning is important in anterior cruciate ligament (ACL) reconstructive surgery. Recent studies have suggested the limitations of a traditional transtibial technique to place the ACL graft within the anatomic tunnel position of the ACL on the femur. The purpose of this study is to determine if the 2-incision tibial tunnel-independent technique can place femoral tunnel to native ACL center when compared with the transtibial technique, as the placement with the tibial tunnel-independent technique is unconstrained by tibial tunnel. Methods In sixty-nine patients, single-bundle ACL reconstruction with preservation of remnant bundle using hamstring tendon autograft was performed. Femoral tunnel locations were measured with quadrant methods on the medial to lateral view of the lateral femoral condyle. Tibial tunnel locations were measured in the anatomical coordinates axis on the top view of the proximal tibia. These measurements were compared with reference data on anatomical tunnel position. Results With the quadrant method, the femoral tunnel centers of the transtibial technique and tibial tunnel-independent technique were located. The mean (± standard deviation) was 36.49% ± 7.65% and 24.71% ± 4.90%, respectively, from the over-the-top, along the notch roof (parallel to the Blumensaat line); and at 7.71% ± 7.25% and 27.08% ± 7.05%, from the notch roof (perpendicular to the Blumensaat line). The tibial tunnel centers of the transtibial technique and tibial tunnel-independent technique were located at 39.83% ± 8.20% and 36.32% ± 8.10%, respectively, of the anterior to posterior tibial plateau depth; and at 49.13% ± 4.02% and 47.75% ± 4.04%, of the medial to lateral tibial plateau width. There was no statistical difference between the two techniques in tibial tunnel position. The tibial tunnel-independent technique used in this study placed femoral tunnel closer to the anatomical ACL anteromedial bundle center. In contrast, the

  16. Anterior Cervical Discectomy and Fusion Using a Double Cylindrical Cage versus an Anterior Cervical Plating System with Iliac Crest Autografts for the Treatment of Cervical Degenerative Disc Disease

    PubMed Central

    Kim, Seong Joon

    2014-01-01

    Objective Anterior cervical discectomy and fusion (ACDF) is often complicated by subsidence, pseudoarthrosis, kyphosis, and graft donor site morbidities. To decrease the occurrence of these complications, various types of cages have been developed. We designed this retrospective study to analyze and compare the efficacy and outcomes of ACDF using double cylindrical cages (DCC) (BK Medical, Seoul, Korea) versus an anterior cervical plating system with autogenous iliac crest grafts. Methods Forty-eight patients were treated with autograft and plating (plate group), and 48 with DCC group from October 2007 to October 2011. We analyzed construct length, cervical lordotic curvarture, the thickness of the prevertebral soft tissue, segmental instability, and clinical outcomes. Results There were no significant differences between the two groups with regard to the decrease in construct length or cervical lodortic curvature at the 3-, 6-, and 12-month follow-ups. The prevertebral soft tissue was thinner in the DCC group than the plate group immediately after surgery and at the 3-, 6-, and 12-month follow-ups. The difference in interspinous distance on flexion-extension was shorter in the plate group than the DCC group at the 3- and 6-month follow-ups. However, there was no significant difference in this distance between the two groups at the 12-month follow-up. Conclusion A double cylindrical cage is a good alternative for fusion in patients with cervical degenerative diseases; the surgical method is relatively simple, allows good synostosis, has less associated prevertebral soft tissue swelling, and complications associated with autografting can be avoided. PMID:24570812

  17. Arthroscopic double-pulley remplissage technique for engaging Hill-Sachs lesions in anterior shoulder instability repairs.

    PubMed

    Koo, Samuel S; Burkhart, Stephen S; Ochoa, Eloy

    2009-11-01

    We present a modified arthroscopic technique used to treat anterior shoulder instability associated with mild glenoid bone loss and a large Hill-Sachs lesion. The procedure aims to convert a bony intra-articular defect into an extra-articular defect by insetting the infraspinatus into the Hill-Sachs lesion. The arthroscopic procedure is performed with the patient in the lateral decubitus position, and the same portals used for anterior instability repair are used for this technique. The sequence of steps involves placing and passing the glenoid anchors and sutures and then waiting to tie the anterior sutures until after the humeral suture anchors have been placed. The subacromial bursa is cleared; then 2 transtendon suture anchors are placed in the Hill-Sachs lesion. Next, the previously placed Bankart repair sutures are tied, and finally, the remplissage sutures are tied in the subacromial space over the infraspinatus by use of the transtendon double-pulley technique. This technique uses the eyelets of the 2 suture anchors as pulleys and creates a double-mattress suture.

  18. Three-Dimensional Reconstruction Computed Tomography Evaluation of the Tunnel Location and Angle in Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction: A Comparison of the Anteromedial Portal and Outside-in Techniques

    PubMed Central

    Kim, Kang-Il; Lee, Sang Hak; Bae, Chanil; Bae, Sung Hae

    2017-01-01

    Purpose The purpose of this study was to compare the geometry and position of the femoral tunnel between the anteromedial portal (AMP) and outside-in (OI) techniques after anatomic single-bundle anterior cruciate ligament (ACL) reconstruction. Materials and Methods We evaluated 82 patients undergoing single-bundle ACL reconstruction with hamstring autografts using either the AMP (n=40) or OI (n=42) technique. The locations of the tunnel apertures were assessed by postoperative 3-dimensional computed tomography imaging. The femoral graft bending angle, femoral tunnel aperture shape, femoral tunnel length, and posterior wall breakage were also measured. Results The mean femoral tunnel position parallel to the Blumensaat line was more caudally positioned in the AMP group than in the OI group (p=0.025) The mean femoral graft angle in the OI group (99.6°±7.1°) was significantly more acute than that of the AMP group (108.9°±10.2°, p<0.001). The mean height/width ratio of the AMP group (1.21±0.20) was significantly more ellipsoidal than that of the OI group (1.07±0.09, p<0.001). Conclusions The mean femoral tunnel position was significantly shallower in the AMP technique than in the OI technique. The OI technique might be more disadvantageous than the AMP technique in terms of the more acute bending angle. PMID:28231643

  19. Double-bubble technique to facilitate Descemet membrane exposure in deep anterior lamellar keratoplasty.

    PubMed

    Shimazaki, Jun

    2010-02-01

    Safe and efficient exposure of Descemet membrane is the key to success in deep anterior lamellar keratoplasty. Although widely used, the big-bubble technique has the drawback of difficulty in maintaining appropriate needle insertion depth in the corneal stroma, resulting in injected air sometimes escaping to the peripheral cornea without separation of Descemet membrane. We describe a variation of the big-bubble technique in which air is injected into the anterior chamber before it is injected into the stroma. By observing the reflection created on the surface of the air, a needle can be inserted deep into the stroma without puncturing Descemet membrane. This allows safe and efficient separation of Descemet membrane. Moreover, air in the anterior chamber can be used as an indicator of successful Descemet membrane separation as air is shifted to the periphery with creation of the big bubble.

  20. Crimp morphology in the ovine anterior cruciate ligament

    PubMed Central

    Zhao, Lei; Thambyah, Ashvin; Broom, Neil

    2015-01-01

    While the crimp morphology in ligaments and tendons has been described in detail in the literature, its relative distribution within the tissue has not been studied, especially in relation to the complex multi-bundle arrangement as is found in the anterior cruciate ligament (ACL). In this study, the crimp morphology of the ovine ACL was examined topologically and with respect to its double-bundle structure. The crimp morphologies were compared with the knee in three knee positions, namely stance, maximum extension and maximum flexion. As a control, the crimp morphology of the ACL free from its bony attachments was determined. In the control samples, the anterior-medial (AM) bundle contained a combination of coarse and fine crimp, whereas the posterior-lateral (PL) bundle manifested only a coarse crimp. Using the extent of crimp loss observed when subjecting the knee to the respective positions, and comparing with the controls, the crimp morphologies show that the AM bundle of the ACL is most active in the stance position, whereas for the maximum extension and flexion positions the PL bundle is most active. We propose that these differences in crimp morphologies have relevance to ACL design and function. PMID:25677165

  1. Double dissociation between action-driven and perception-driven conflict resolution invoking anterior versus posterior brain systems.

    PubMed

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

    2009-11-01

    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.

  2. Functional and computed tomography correlation of femoral and tibial tunnels in single-bundle anterior cruciate ligament reconstruction: Use of accessory anteromedial portal

    PubMed Central

    Mathai, Naveen Joseph; Amaravathi, Rajkumar S; Pavan, KV; Sekaran, Padmanabhan; Sharma, Gaurav; Codanda, Belliappa

    2016-01-01

    Background: An accessory anteromedial portal (AAMP) has been shown to be effective in placing an anatomically ideal femoral tunnel. It is well known that this is due to the independent femoral drilling which is possible with the AAMP. However very little is known regarding the significance of this reconstruction technique in influencing the functional outcomes of anatomic anterior cruciate ligament reconstruction (ACLR). This study documents the influence of tibial and femoral tunnel positions on functional outcomes of anatomic ACLR using the AAMP. Materials and Methods: 41 patients who underwent anatomic ACLR between 2011 and 2013 were included in this prospective cohort study. The primary outcome involved the documentation of femoral and tibial tunnel positions with volume rendering imaging using a three-dimensional computed tomography (3D-CT) done at the end of 1 year. The tunnel position evaluations from the CT images were performed by an independent observer specializing in radiodiagnosis. Functional outcome measures included preoperative and postoperative Lysholm and International Knee Documentation Committee (IKDC) scores (subjective) documented by an independent investigator who was not involved with the surgical procedure, at the end of 1 year. Results: The minimum followup was 1 year. All patients achieved good clinical and functional outcomes postoperatively with no reported complications. Tunnel position evaluations with 3D-CT revealed the average tibial tunnel distance to be 15.5 mm (standard deviation [SD] =2.52) from the anterior border of the tibial plateau and the average femoral tunnel distance to be 14.33 mm (SD = 2.6) from the inferior margin of the medial surface of lateral femoral condyle and 13.72 mm (SD = 2.8) from the posterior margin of the medial surface of lateral femoral condyle. The average tunnel diameters were found to be 7.9 mm (SD = 0.72) for the tibial tunnels and 8.6 mm (SD = 1.07) for the femoral tunnels. Statistically

  3. Anatomic single-bundle anterior cruciate ligament reconstruction using the outside-in femoral tunnel drilling technique: a prospective study and short- to mid-term results.

    PubMed

    Abdelkafy, Ashraf

    2015-03-01

    Anatomic positioning of the femoral and tibial tunnels in the native ACL femoral and tibial footprints requires an independent drilling either via an accessory medial portal (trans-portal drilling) or using an outside-in drilling technique. Conventional trans-tibial drilling (dependant drilling) was found to lack the ability to accurately position the femoral tunnel in the native ACL footprint. The purpose of the current study was to evaluate the functional outcome results of anatomic single-bundle ACLR using the OI femoral tunnel drilling technique. Single surgeon single center prospective case series study. 64 patients having complete ACL tears were included in the current study. Average follow-up was 15.8 months (range 8-25). Objective and subjective IKDC scores, Lysholm knee score, SF-36 score, VAS for patients' satisfaction, VAS for pain and Kellgren and Lawrence (K/L) classification of osteoarthritis were used for follow-up evaluation. Objective IKDC score revealed that 60 patients had grade ''A'' and 4 had grade ''B'', while no single patient had neither grade ''C'' nor ''D''. The average Lysholm Score was 92.4, average subjective IKDC was 91.5. Average SF-36 score was 96.7. The average VAS for operation satisfaction was 9.7. Average VAS for pain was 0.3. Forty-nine patients were classified as normal K/L classification, 7 were grade ''1'', 8 were grade ''2''. Comparing pre-operative and follow-up Objective IKDC, Subjective IKDC, Lysholm, SF-36 and VAS for pain scores revealed statistically significant differences (P value <0.05). Arthroscopic-assisted ACL reconstruction using the outside-in femoral tunnel drilling technique shows a good and satisfactory functional outcome results at short- to mid-term follow-up. Level IV.

  4. Editorial Commentary: The Ribbon Theory. Another Quantum Leap? The Anterior Cruciate Ligament Is Twisted and in Fact a Flat Structure. Or not?

    PubMed

    Hohmann, Erik

    2017-09-01

    Is the double bundle structure of the anterior cruciate ligament (ACL) a myth? Derotation untwists the ACL and results in a flat ribbon structure. However, other researchers dispute this theory and revealed 2 distinct bundles separated by a synovial septum. The answer is simple: we do not know and the evidence is conflicting. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  5. 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

  6. Arthroscopic Double-Row Anterior Stabilization and Bankart Repair for the “High-Risk” Athlete

    PubMed Central

    Moran, Cathal J.; Fabricant, Peter D.; Kang, Richard; Cordasco, Frank A.

    2014-01-01

    In addition to operative intervention for the patient with recurrent shoulder instability, current literature suggests that younger athletic patients unwilling to modify their activities may benefit from an early surgical shoulder stabilization procedure. Although open shoulder stabilization clearly has a role to play in some cases, we believe that further optimization of arthroscopic fixation techniques may allow us to continue to refine the indications for open stabilization. In particular, when an arthroscopic approach is used for capsulolabral repair in relatively high-risk groups, it may be beneficial to use a double-row repair technique. We describe our technique for shoulder stabilization through double-row capsulolabral repair of a soft-tissue Bankart lesion in the high-risk patient with shoulder instability or the patient with a small osseous Bankart lesion. PMID:24749044

  7. Arthroscopic double-row anterior stabilization and bankart repair for the "high-risk" athlete.

    PubMed

    Moran, Cathal J; Fabricant, Peter D; Kang, Richard; Cordasco, Frank A

    2014-02-01

    In addition to operative intervention for the patient with recurrent shoulder instability, current literature suggests that younger athletic patients unwilling to modify their activities may benefit from an early surgical shoulder stabilization procedure. Although open shoulder stabilization clearly has a role to play in some cases, we believe that further optimization of arthroscopic fixation techniques may allow us to continue to refine the indications for open stabilization. In particular, when an arthroscopic approach is used for capsulolabral repair in relatively high-risk groups, it may be beneficial to use a double-row repair technique. We describe our technique for shoulder stabilization through double-row capsulolabral repair of a soft-tissue Bankart lesion in the high-risk patient with shoulder instability or the patient with a small osseous Bankart lesion.

  8. A double dissociation between mood states and personality traits in the anterior cingulate.

    PubMed

    Canli, Turhan; Amin, Zenab; Haas, Brian; Omura, Kazufumi; Constable, R Todd

    2004-10-01

    Neuroticism and extraversion are personality traits associated with negative and positive mood states, respectively, confounding trait and state factors that may affect brain responses to emotional stimuli. The authors dissociated these factors using fMRI and the emotional Stroop attention task: Anterior cingulate (AC) response to positive stimuli varied as a function of personality trait, but not mood state, whereas AC response to negative stimuli varied as a function of mood state, but not personality trait. Negative mood, but not personality trait, also increased the functional connectivity between AC and other regions. Variance in AC activation can thus be ascribed to an intersubject variable (extraversion) when responding to positive stimuli and an intrasubject variable (mood) when responding to negative stimuli. The former may explain stable differences between extraverts and introverts. The latter may provide an adaptive mechanism to expand an individual's dynamic range in response to potentially dangerous or threatening stimuli. Copyright 2004 APA.

  9. Surgical Adjustment of the Guide Pin to Perform a Correct Tibial Tunnel in Anatomical Anterior Cruciate Ligament Single-Bundle Reconstruction.

    PubMed

    Kumar, Bharath S; Andrade, Renato; Leal, Ana; Sarmento, André; Pereira, Hélder; Sevivas, Nuno; Espregueira-Mendes, João

    2016-08-01

    Anatomical positioning of the graft in anterior cruciate ligament reconstruction is important to restore normal knee kinematics and prevent early joint degeneration. Inadequate position of a first attempt to place the guide pin within the center of the tibial footprint may occur. Therefore, its adjustment is important to achieve the anatomical positioning of the graft within the tibial footprint. When the guide pin exits eccentrically in an inadequate position, it is possible to correct it to the center of the footprint. A small tunnel with a 4.5-mm reamer is made and the guide pin is shifted to the center of the footprint. The center of the tunnel can be corrected until 50% and in all direction in relation to the initial drilled tunnel, without additional associated morbidity. Once the correct position of the center is achieved, the guide pin is fixed in the femoral notch roof to guarantee the accurate correction of the axis, without toggling of the guide pin inside the tunnel and metal dusting. The final tunnel is then drilled with the same size of the graft. With this technique it is possible to adjust an eccentrically misplaced guide pin to the center of the footprint without additional morbidity.

  10. Combined in vivo/in vitro method to study anteriomedial bundle strain in the anterior cruciate ligament using a dynamic knee simulator.

    PubMed

    Cassidy, Karla; Hangalur, Gajendra; Sabharwal, Preet; Chandrashekar, Naveen

    2013-03-01

    The mechanism of noncontact anterior cruciate ligament (ACL) injury is not well understood. It is partly because previous studies have been unable to relate dynamic knee muscle forces during sports activities such as landing from a jump to the strain in the ACL. We present a combined in vivo/in vitro method to relate the muscle group forces to ACL strain during jump-landing using a newly developed dynamic knee simulator. A dynamic knee simulator system was designed and developed to study the sagittal plane biomechanics of the knee. The simulator is computer controlled and uses six powerful electromechanical actuators to move a cadaver knee in the sagittal plane and to apply dynamic muscle forces at the insertion sites of the quadriceps, hamstring, and gastrocnemius muscle groups and the net moment at the hip joint. In order to demonstrate the capability of the simulator to simulate dynamic sports activities on cadaver knees, motion capture of a live subject landing from a jump on a force plate was performed. The kinematics and ground reaction force data obtained from the motion capture were input into a computer based musculoskeletal lower extremity model. From the model, the force-time profile of each muscle group across the knee during the movement was extracted, along with the motion profiles of the hip and ankle joints. This data was then programmed into the dynamic knee simulator system. Jump-landing was simulated on a cadaver knee successfully. Resulting strain in the ACL was measured using a differential variable reluctance transducer (DVRT). Our results show that the simulator has the capability to accurately simulate the dynamic sagittal plane motion and the dynamic muscle forces during jump-landing. The simulator has high repeatability. The ACL strain values agreed with the values reported in the literature. This combined in vivo/in vitro approach using this dynamic knee simulator system can be effectively used to study the relationship between sagittal

  11. Fuel bundle

    SciTech Connect

    Lui, C.K.

    1989-04-04

    This patent describes a method of forming a fuel bundle of a nuclear reactor. The method consists of positioning the fuel rods in the bottom plate, positioning the tie rod in the bottom plate with the key passed through the receptacle to the underside of the bottom plate and, after the tie rod is so positioned, turning the tie rod so that the key is in engagement with the underside of the bottom plate. Thereafter mounting the top plate is mounted in engagement with the fuel rods with the upper end of the tie rod extending through the opening in the top plate and extending above the top plate, and the tie rod is secured to the upper side of sid top plate thus simultaneously securing the key to the underside of the bottom plate.

  12. Utility of the Anterior Oblique-Viewing Endoscope and the Double-Balloon Enteroscope for Endoscopic Retrograde Cholangiopancreatography in Patients with Billroth II Gastrectomy

    PubMed Central

    Sen-yo, Manabu; Kaino, Seiji; Suenaga, Shigeyuki; Uekitani, Toshiyuki; Yoshida, Kanako; Harano, Megumi; Sakaida, Isao

    2012-01-01

    Background/Purpose. The difficulties of endoscopic retrograde cholangiopancreatography in patients with Billroth II gastrectomy have been reported. We evaluated the usefulness of an anterior oblique-viewing endoscope and a double-balloon enteroscope for endoscopic retrograde cholangiopancreatography in such patients. Methods. From January 2003 to December 2011, 65 patients with Billroth II gastrectomy were enrolled in this study. An anterior oblique-viewing endoscope was used for all patients. From February 2007, a double-balloon enteroscope was used for the failed cases. The success rate of procedures was compared with those in 20 patients with Billroth II gastrectomy using forward-viewing endoscope or side-viewing endoscope from March 1996 to July 2002 as historical controls. Results. In all patients in whom the papilla was reached (60/65), selective cannulation was achieved. The success rate of selective cannulation and accomplishment of planned procedures in the anterior oblique-viewing endoscope group were both significantly higher than that in the control group (100% versus 70.1%, 100 versus 58.8%, resp.). A double-balloon enteroscope was used in 2 patients, and the papilla could be reached and the planned procedures completed. Conclusions. An anterior oblique-viewing endoscope and double-balloon enteroscope appear to be useful in performing endoscopic retrograde cholangiopancreatography in patients with Billroth II gastrectomy. PMID:23056039

  13. Single-bundle anterior cruciate ligament reconstruction: a biomechanical cadaveric study of a rectangular quadriceps and bone--patellar tendon--bone graft configuration versus a round hamstring graft.

    PubMed

    Herbort, Mirco; Tecklenburg, Katja; Zantop, Thore; Raschke, Michael J; Hoser, Christian; Schulze, Martin; Petersen, Wolf; Fink, Christian

    2013-12-01

    The purposes of this study were to investigate anterior tibial translation under loading conditions after single-bundle (SB) anterior cruciate ligament (ACL) reconstruction using a rectangular tunnel placement strategy with quadriceps and bone--patellar tendon--bone (BPTB) graft and to compare these data with a SB hamstring reconstruction with a round tunnel design. In 9 human cadaveric knees, the knee kinematics were examined with robotic/universal force-moment sensor testing. Within the same specimen, the knee kinematics under simulated pivot-shift and KT-1000 arthrometer (MEDmetric, San Diego, CA) testing were determined at 0°, 15°, 30°, 60°, and 90° of flexion under different conditions: intact knee, ACL-deficient knee, and SB ACL-reconstructed knee. For the SB ACL-reconstructed knee, 3 different SB reconstruction techniques were used: a rectangular tunnel strategy (9 × 5 mm) with quadriceps graft, a rectangular tunnel strategy with BPTB graft, and a round tunnel strategy (7 mm) with hamstring graft. In a simulated Lachman test, a statistically significant difference was found at 0° and 15° of knee flexion between the rectangular reconstruction with quadriceps graft (5.1 ± 1.2 mm and 8.3 ± 2 mm, respectively) or BPTB graft (5.3 ± 1.5 mm and 8 ± 1.9 mm, respectively) and the reconstruction using hamstring graft (7.2 ± 1.4 mm and 12 ± 1.8 mm, respectively) (P = .032 and P = .033, respectively, at 0°; P = .023 and P = .02, respectively, at 15°). On the simulated pivot-shift test at 0° and 15°, rectangular ACL reconstruction with quadriceps graft (3.9 ± 2.1 mm and 6.5 ± 1.7 mm, respectively) or BPTB graft (4.2 ± 1.8 mm and 6.7 ± 1.7 mm, respectively) showed a significantly lower anterior tibial translation when compared with round tunnel reconstruction (5.5 ± 2.1 mm and 7.9 ± 1.9 mm, respectively) (P = .03 and P = .041, respectively, at 0°; P = .042 and P = .046, respectively, at 15°). Under simulated Lachman testing and pivot

  14. Double-layer versus single-layer bone-patellar tendon-bone anterior cruciate ligament reconstruction: a prospective randomized study with 3-year follow-up.

    PubMed

    Mei, Xiaoliang; Zhang, Zhenxiang; Yang, Jingwen

    2016-12-01

    To evaluate the clinical results of a randomized controlled trial of single-layer versus double-layer bone-patellar tendon-bone (BPTB) anterior cruciate ligament (ACL) reconstruction. Fifty-eight subjects who underwent primary ACL reconstruction with a BPTB allograft were prospectively randomized into two groups: single-layer reconstruction (n = 31) and double-layer reconstruction (n = 27). The following evaluation methods were used: clinical examination, KT-1000 arthrometer measurement, muscle strength, Tegner activity score, Lysholm score, subjective rating scale regarding patient satisfaction and sports performance level, graft retear, contralateral ACL tear, and additional meniscus surgery. Forty-eight subjects (24 in single-layer group and 24 in double-layer group) who were followed up for 3 years were evaluated. Preoperatively, there were no differences between the groups. At 3-year follow-up, the Lachman and pivot-shift test results were better in the double-layer group (P = 0.019 and P < 0.0001, respectively). KT measurements were better in the double-layer group (mean 2.9 versus 1.5 mm; P = 0.0025). The Tegner score was also better in the double-layer group (P = 0.024). There were no significant differences in range of motion, muscle strength, Lysholm score, subjective rating scale, graft retear, and secondary meniscal tear. In ACL reconstruction, double-layer BPTB reconstruction was significantly better than single-layer reconstruction regarding anterior and rotational stability at 3-year follow-up. The results of KT measurements and the Lachman and pivot-shift tests were significantly better in the double-layer group, whereas there was no difference in the anterior drawer test results. The Tegner score was also better in the double-layer group; however, there were no differences in the other subjective findings.

  15. Anterior Cruciate Ligament Injury, Reconstruction, and the Optimization of Outcome

    PubMed Central

    Bliss, James Philip

    2017-01-01

    Anterior cruciate ligament reconstruction (ACLR) provides an established surgical intervention to control pathological tibiofemoral translational and rotational movement. ACLR is a safe and reproducible intervention, but there remains an underlying rate of failure to return to preinjury sporting activity levels. Postoperative pathological laxity and graft reinjury remain concerns. Previously, unrecognized meniscal lesions, disruption of the lateral capsule, and extracapsular structures offer potential avenues to treat and to therefore improve kinematic outcome and functional results, following reconstruction. Addressing laterally based injuries may also improve the durability of intraarticular ACLR. Improving the anterior cruciate ligament (ACL) graft replication of the normal ACL attachment points on the femur and the tibia, using either double bundle or anatomical single bundle techniques, improves kinematics, which may benefit outcome and functionality, following reconstruction. PMID:28966384

  16. Lower extremity muscle activation onset times 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

    2016-06-01

    Previous studies mainly focused on muscles at the operated knee after anterior cruciate ligament reconstruction, less on muscles around other joints of the operated and non-operated leg. The aim of this study was to investigate muscle activation onset times during the transition from double-leg stance to single-leg stance in anterior cruciate ligament reconstructed subjects. Lower extremity muscle activation onset times of both legs of 20 fully returned to sport anterior cruciate ligament reconstructed subjects and 20 non-injured control subjects were measured during the transition from double-leg stance to single-leg stance in eyes open and eyes closed conditions. Analysis of covariance (ANCOVA) was used to evaluate differences between groups and differences between legs within both groups, while controlling for peak center of pressure velocity. Significantly delayed muscle activation onset times were found in the anterior cruciate ligament reconstructed group compared to the control group for gluteus maximus, gluteus medius, vastus medialis obliquus, medial hamstrings, lateral hamstrings and gastrocnemius in both eyes open and eyes closed conditions (P<.05). Within the anterior cruciate ligament reconstructed group, no significant different muscle activation onset times were found between the operated and non-operated leg (P>.05). Despite completion of rehabilitation and full return to sport, the anterior cruciate ligament reconstructed group showed neuromuscular control deficits that were not limited to the operated knee joint. Clinicians should focus on relearning multi-segmental anticipatory neuromuscular control strategies after anterior cruciate ligament reconstruction. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Clinical problems with a double tooth and a macrodont in the maxillary anterior area: a case report.

    PubMed

    Ghijselings, Ellen; van Gastel, Jan; Verdonck, An; Carels, Carine

    2014-11-01

    Fusion is defined as the union between dentine and/or enamel of two normally separated teeth. Gemination is the cleavage of the forming dental germ to produce two partial teeth. The distinction between the conditions is often determined by the number of teeth present. However, this can be confused if supernumerary teeth are considered. The present case report describes the treatment of a patient who presented with dental fusion and macrodontia involving both upper central incisors. Besides the central incisors displaying characteristics of macrodonts, tooth 21 also showed aspects of fusion. Management consisted of the extraction of 11 and 21 and orthodontic mesialisation of the maxillary dentition. Treatment was planned in two phases and at the end of the orthodontic phase, the upper anterior teeth were to be reshaped using composite resin. Orthodontic space closure is a treatment option in the clinical management of an extracted maxillary central double and/or macrodontic tooth. As no permanent teeth were absent, it was presumed that the fusion of 21 occurred with a supernumerary tooth. Multidisciplinary treatment following the extraction of maxillary central incisors is reported with special attention to the orthodontic and restorative considerations required to improve the aesthetic outcome.

  18. Postural stability 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

    2015-03-01

    An anterior cruciate ligament injury may lead to deteriorations in postural stability. The goal of this study was to evaluate postural stability during the transition from double-leg stance to single-leg stance of both legs in anterior cruciate ligament injured subjects and non-injured control subjects with a standardized methodology. Fifteen control subjects and 15 anterior cruciate ligament injured subjects (time after injury: mean (SD)=1.4 (0.7) months) participated in the study. Both groups were similar for age, gender, height, weight and body mass index. Spatiotemporal center of pressure outcomes of both legs of each subject were measured during the transition from double-leg stance to single-leg stance 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 single-leg stance phase was significantly increased in the anterior cruciate ligament injured group compared to the control group in the eyes closed condition (P<.001). No significant different postural stability outcomes were found between both legs within both groups (P>.05). No significant differences were found during the transition itself (P>.05). The anterior cruciate ligament injured group showed postural stability deficits during the single-leg stance phase compared to the non-injured control group in the eyes closed condition. Using the non-injured leg as a normal reference when evaluating postural stability of the injured leg may lead to misinterpretations, as no significant differences were found between the injured and non-injured leg of the anterior cruciate ligament injured group. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. F actin bundles in Drosophila bristles. I. Two filament cross-links are involved in bundling

    PubMed Central

    1995-01-01

    Transverse sections though Drosophila bristles reveal 7-11 nearly round, plasma membrane-associated bundles of actin filaments. These filaments are hexagonally packed and in a longitudinal section they show a 12-nm periodicity in both the 1.1 and 1.0 views. From earlier studies this periodicity is attributable to cross-links and indicates that the filaments are maximally cross-linked, singed mutants also have 7-11 bundles, but the bundles are smaller, flattened, and the filaments within the bundles are randomly packed (not hexagonal); no periodicity can be detected in longitudinal sections. Another mutant, forked (f36a), also has 7-11 bundles but even though the bundles are very small, the filaments within them are hexagonally packed and display a 12-nm periodicity in longitudinal section. The singed-forked double mutant lacks filament bundles. Thus there are at least two species of cross-links between adjacent actin filaments. Hints of why two species of cross-links are necessary can be gleaned by studying bristle formation. Bristles sprout with only microtubules within them. A little later in development actin filaments appear. At early stages the filaments in the bundles are randomly packed. Later the filaments in the bundles become hexagonally packed and maximally cross-linked. We consider that the forked proteins may be necessary early in development to tie the filaments together in a bundle so that they can be subsequently zippered together by fascin (the singed gene product). PMID:7622563

  20. Bundle brunch reentrant ventricular tachycardia with two distinct conduction patterns in a patient with complete right bundle branch block.

    PubMed

    Enjoji, Yoshihisa; Mizobuchi, Masahiro; Shibata, Kensaku; Ono, Tsuyoshi; Funatsu, Atsushi; Kanbayashi, Daisuke; Kobayashi, Tomoko; Nakamura, Shigeru

    2006-12-01

    We report a rare case of bundle branch reentrant ventricular tachycardia [BBRVT]. A 67-year-old female was admitted for management of wide QRS tachycardia (right bundle branch block [RBBB] and a southwest axis). The mapping procedure revealed the tachycardia circuit consisted of the left anterior fascicle (LAF) as an antegrade, and the right bundle as a retrograde pathway. She presented RBBB during sinus rhythm. LAF ablation changed the tachycardia configuration to a northwest axis and prolonged the cycle length. Left posterior fascicle ablation terminated the tachycardia, and complete atrioventricular block occurred, which showed the unidirectional conduction over the right bundle.

  1. Anterior cruciate ligament reconstruction: bone-patellar tendon-bone compared with double semitendinosus and gracilis tendon grafts. A prospective, randomized clinical trial.

    PubMed

    Aglietti, Paolo; Giron, Francesco; Buzzi, Roberto; Biddau, Flavio; Sasso, Francesco

    2004-10-01

    The choice of graft for anterior cruciate ligament reconstruction is a matter of debate, with patellar and hamstring tendons being the two most popular autologous graft options. The objective of this study was to determine in a prospective, randomized clinical trial whether two grafts (bone-patellar tendon-bone or doubled hamstring tendons) fixed with modern devices affect the two-year minimum clinical and radiographic outcomes of anterior cruciate ligament reconstruction. One hundred and twenty patients with a chronic unilateral rupture of the anterior cruciate ligament underwent arthroscopically assisted reconstruction with use of either autologous bone-patellar tendon-bone or doubled hamstring tendon grafts, in a strictly alternating manner. Both groups were comparable with regard to demographic data, preoperative activity level, mechanism of injury, interval between the injury and the operation, and the amount of knee laxity present preoperatively. The same well-proven surgical technique and aggressive controlled rehabilitation was used. An independent observer, who was blinded with regard to the involved leg and the type of graft, performed the outcome assessment with use of a visual analog scale, the new International Knee Documentation Committee form, the Knee Injury and Osteoarthritis Outcome Score, the Functional Knee Score for Anterior Knee Pain, and an arthrometric and an isokinetic dynamometric evaluation. Radiographs were also made. At the two-year follow-up evaluation, no differences were found in terms of the visual analog score, the Knee Injury and Osteoarthritis Outcome Score, the new International Knee Documentation Committee subjective and objective evaluation scores, the KT-1000 side-to-side laxity measurements, the Functional Knee Score for Anterior Knee Pain, muscle strength recovery, or return to sports activities. In the bone-patellar tendon-bone group, we found a higher prevalence of postoperative kneeling discomfort (p < 0.01) and an

  2. 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

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

    PubMed

    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.

  4. [Anterior cruciate ligament-plasty using the "U-dos" technique].

    PubMed

    Morales-Trevizo, C; Paz-García, M; Leal-Berumen, I; Leal-Contreras, C; Berumen-Nafarrate, E

    2013-01-01

    The knee is a compound diarthrodial joint, vulnerable to serious injuries such as ligament injuries of: medial collateral ligament, lateral collateral ligament, anterior cruciate ligament and posterior cruciate ligament, as cruciate ligaments limit rotation movement in the joint. The purpose of our study was to create a new technique to treat injuries of the anterior cruciate ligament, which is composed of two bundles--anteromedial and posterolateral--trying to achieve an anatomical reconstruction that allows for a normal biomechanical recovery. This technique reduces the use of fixation material and costs. The diagnosis of anterior cruciate ligament injuries was made with the pivot shift test. There are currently two repair methods for anterior cruciate ligament injuries: single bundle or double bundle repair; none of these techniques is considered as the gold standard, as their results are very similar. This paper describes a technique used for the treatment of anterior cruciate ligament injuries, known as "U-dos", and its clinical results. Cross-sectional, observational study that enrolled 20 patients with total anterior cruciate ligament injuries who underwent anterior cruciate ligament plasty using the "U-dos" technique between June 2009 and June 2010. The technique requires the use of bone bank allograft, in this case of the anterior tibial ligament. Patients were assessed using the Lysholm scale and the pivot shift test. Our results show that all the pivot shift tests were negative and assessments according to the Lysholm scale were from normal to excellent in 95% of cases (19/20). Only one failure was reported, with avulsion of the graft attachment which required a surgical intervention.

  5. Implementing sepsis bundles

    PubMed Central

    Jozwiak, Mathieu; Monnet, Xavier

    2016-01-01

    Sepsis bundles represent key elements of care regarding the diagnosis and treatment of patients with septic shock and allow ones to convert complex guidelines into meaningful changes in behavior. Sepsis bundles endorsed the early goal-directed therapy (EGDT) and their implementation resulted in an improved outcome of septic shock patients. They induced more consistent and timely application of evidence-based care and reduced practice variability. These benefits mainly depend on the compliance with sepsis bundles, highlighting the importance of dedicated performance improvement initiatives, such as multifaceted educational programs. Nevertheless, the interest of early goal directed therapy in septic shock patients compared to usual care has recently been questioned, leading to an update of sepsis bundles in 2015. These new sepsis bundles may also exhibit, as the previous bundles, some limits and pitfalls and the effects of their implementation still needs to be evaluated. PMID:27713890

  6. Anterior cruciate ligament injuries: anatomy, physiology, biomechanics, and management.

    PubMed

    Siegel, Leon; Vandenakker-Albanese, Carol; Siegel, David

    2012-07-01

    Anterior cruciate ligament (ACL) injuries are the most common ligament injury in the United States. These injuries can be career ending for athletes and severely disabling for all individuals. Our objectives are to review the epidemiology of these injuries, as well as ACL biomechanics, anatomy, and nonsurgical and surgical management so that generalists as well as sports medicine physicians, orthopedists, and others will have a better understanding of this serious injury as well as choices in its management. PubMed was used to identify relevant articles. These articles were then used to identify other sources. Anterior cruciate ligament injuries occur more commonly in women than in men due to a variety of anatomical factors. The ACL consists of 2 major bundles, the posterolateral and the anteromedial bundles. Forces transmitted through these bundles vary with knee-joint position. Some patients with ACL injuries may not be candidates for surgery because of serious comorbid medical conditions. However, without surgical repair, the knee generally remains unstable and prone to further injury. There are a variety of surgical decisions that can influence outcomes. Single-bundle versus double-bundle repair, whether to leave the ruptured ACL remnant in the knee, the selection of the graft tissue, graft placement, and whether to use the transtibial, far anteromedial portal, or tibial tunnel-independent technique are choices that must be made. With a sound knowledge of the anatomy and kinetics of the knee, newer improved surgical techniques have been developed that can restore proper knee function and have allowed many athletes to resume their careers. These new techniques have also limited the disability in nonathletes.

  7. Gross, Arthroscopic, and Radiographic Anatomies of the Anterior Cruciate Ligament: Foundations for Anterior Cruciate Ligament Surgery.

    PubMed

    Irarrázaval, Sebastián; Albers, Marcio; Chao, Tom; Fu, Freddie H

    2017-01-01

    The anterior cruciate ligament (ACL) is one of the more studied structures in the knee joint. It is not a tubular structure, but is much narrower in its midsubstance and broader at its ends, producing an hourglass shape. The ACL is composed of 2 functional bundles, the anteromedial and posterolateral bundles, that are named for their location of insertion on the anterior surface of the tibial plateau. Although the relative contribution in terms of total cross-sectional area of the ACL has been noted to be equal in regards to each bundle, dynamically these bundles demonstrate different properties for knee function.

  8. Polycation induced actin bundles.

    PubMed

    Muhlrad, Andras; Grintsevich, Elena E; Reisler, Emil

    2011-04-01

    Three polycations, polylysine, the polyamine spermine and the polycationic protein lysozyme were used to study the formation, structure, ionic strength sensitivity and dissociation of polycation-induced actin bundles. Bundles form fast, simultaneously with the polymerization of MgATP-G-actins, upon the addition of polycations to solutions of actins at low ionic strength conditions. This indicates that nuclei and/or nascent filaments bundle due to attractive, electrostatic effect of polycations and the neutralization of repulsive interactions of negative charges on actin. The attractive forces between the filaments are strong, as shown by the low (in nanomolar range) critical concentration of their bundling at low ionic strength. These bundles are sensitive to ionic strength and disassemble partially in 100 mM NaCl, but both the dissociation and ionic strength sensitivity can be countered by higher polycation concentrations. Cys374 residues of actin monomers residing on neighboring filaments in the bundles can be cross-linked by the short span (5.4Å) MTS-1 (1,1-methanedyl bismethanethiosulfonate) cross-linker, which indicates a tight packing of filaments in the bundles. The interfilament cross-links, which connect monomers located on oppositely oriented filaments, prevent disassembly of bundles at high ionic strength. Cofilin and the polysaccharide polyanion heparin disassemble lysozyme induced actin bundles more effectively than the polylysine-induced bundles. The actin-lysozyme bundles are pathologically significant as both proteins are found in the pulmonary airways of cystic fibrosis patients. Their bundles contribute to the formation of viscous mucus, which is the main cause of breathing difficulties and eventual death in this disorder.

  9. Bundle Branch Block

    MedlinePlus

    ... your heart to pump blood efficiently through your circulatory system. There's no specific treatment for bundle branch block itself. However, any underlying health condition that caused bundle branch block, such as heart disease, will need to be treated. In most people, ...

  10. "Bundling" in Learning.

    ERIC Educational Resources Information Center

    Spiegel, U.; Templeman, J.

    1996-01-01

    Applies the literature of bundling, tie-in sales, and vertical integration to higher education. Students are often required to purchase a package of courses, some of which are unrelated to their major. This kind of bundling policy can be utilized as a profit-maximizing strategy for universities exercising a degree of monopolistic power. (12…

  11. 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

  12. 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

    Arts, Mark P; Rettig, Thijs C D; de Vries, Jessica; Wolfs, Jasper F C; in't Veld, Bas A

    2013-09-25

    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. 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. Postoperative dysphagia occurs frequently after anterior cervical spine surgery. This may be related to high endotracheal tube cuff pressure. Whether

  13. 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

  14. Microsurgically critical anomaly of the anterior communicating artery complex during the pterional approach to a ruptured aneurysm: double fenestration of the proximal A2 segments.

    PubMed

    Namiki, Jun; Doumoto, Youichi

    2003-06-01

    A 50-year-old man presented with a ruptured aneurysm of the anterior communicating artery (ACoA) complex anomaly with the neck of the aneurysm located in the upper ACoA. The right pterional approach was performed 2 days after admission. Retraction of the frontal lobe exposed the lower half of the ACoA complex consisting of the origins of the bilateral A2 segments, and the apparent neck of the aneurysm was clipped. However, further exposure of the bilateral A2 segments revealed double fenestration of the proximal A2 segments, a subtype of duplication of the ACoA accompanied by a bridging artery between the upper and lower ACoA. The limited visualization of this ACoA complex anomaly with an aneurysm had led to the proximal origin of the bridging artery being mistaken for the neck of the aneurysm. Such double fenestration of the proximal A2 segments is a microsurgically critical anomaly of the ACoA complex, because the bridging artery mimics the neck of an aneurysm when visualized by the pterional approach.

  15. Accurate Positioning of Femoral and Tibial Tunnels in Single Bundle Anterior Cruciate Ligament Reconstruction Using the Indigenously Made Bernard and Hurtle Grid on a Transparency Sheet and C-arm.

    PubMed

    Kumar, Sudeep; Kumar, Anup; Kumar, Ravi

    2017-06-01

    Many factors determine the outcome of the anterior cruciate ligament reconstruction surgery. The single most important factor, also well within the control of a surgeon, is tunnel placement. It is difficult to accurately determine the center of the anterior cruciate ligament foot print, and many a times it is also difficult to accurately define the intercondylar and bifurcate ridge. This makes determination of the accurate entry point of the guidewire difficult. We have printed our indigenously formed grid (equidistant boxes) on an old-fashioned transparency sheet. We use a fluoroscopy (C-arm) shot intraoperatively in the lateral position and superimpose this sheet to determine the position of the guidewire by calculating the percentage of boxes. We aim at 27.7% in proximal to distal and 37.5% in anterior to posterior on the femur side and 45% in front to back and medial to lateral on the tibial side. C-arm is freely available, but the inbuilt grid facility may be available in only the higher version of C-arms. Our indigenously designed grid can be easily used across the globe with ease to achieve accuracy in tunnel placement without violating anatomy and without any extra cost.

  16. Comparison between Nintendo Wii Fit and conventional rehabilitation on functional performance outcomes after hamstring anterior cruciate ligament reconstruction: prospective, randomized, controlled, double-blind clinical trial.

    PubMed

    Baltaci, Gul; Harput, Gulcan; Haksever, Bunyamin; Ulusoy, Burak; Ozer, Hamza

    2013-04-01

    The aim of this prospective, randomized, controlled, double-blind clinical trial was to compare the outcomes, including knee strength, balance, coordination, proprioception and response time, of Nintendo Wii Fit with those of conventional rehabilitation on the subjects with anterior cruciate ligament reconstruction. Thirty volunteer subjects were enrolled in either Wii Fit (n = 15; mean age, 29 ± 7 years) or conventional rehabilitation (n = 15; mean age, 29 ± 6 years) programmes from the first week up to 12th weeks of the operation. Endoscopic reconstruction of a completely ruptured ACL was performed by using graft harvested from hamstrings. Each subject underwent an individual therapeutic programme. Functional examinations included the measurements of the balance using modified star excursion balance test, coordination, proprioception and response time using functional squat system and strength of flexor and extensor muscles of the involved and uninvolved leg using an isokinetic machine. There was no significant difference between Wii Fit and conventional group in terms of isokinetic knee strength at 12th week, and dynamic balance, and functional squat tests including coordination, proprioception and response time at first, 8th and 12th weeks of the rehabilitation. Two different 12-week-physiotherapy programmes following ACL reconstruction have the same affect on muscle strength, dynamic balance and functional performance values in both groups. We considered that the practice of Wii Fit activities like conventional rehabilitation could also address physical therapy goals, which included improving visual-perceptual processing, coordination, proprioception and functional mobility.

  17. Forest Residues Bundling Project

    Treesearch

    U.S. Forest Service

    2007-01-01

    During the summer of 2003, the U.S. Forest Service conducted an evaluation of biomass bundling for forest residue extraction. This CD provides a report of the project results, a video documentary project record, and a collection of images from the project. Additional information is available at:

  18. Oral vitamins C and E as additional treatment in patients with acute anterior uveitis: a randomised double masked study in 145 patients

    PubMed Central

    van Rooij, J.; Schwartzenberg, S.; Mulder, P.; Baarsma, S.

    1999-01-01

    AIM—To investigate the effect of additional oral vitamins C and E on acute anterior uveitis.
METHODS—A placebo controlled double masked study on the effect of vitamin C 500 mg in combination with vitamin E 100 mg twice daily in 145 patients with acute anterior uveitis. As a primary end point variable, laser cell/flare measurements were performed. Best corrected and stenopeic visual acuity (VA) testing and clinical variable scores were measured.
RESULTS—Laser flare measurements (ph/s) before treatment were 207.1 (SD 258) in the vitamin group and 143.6 (156) in the placebo group. After 3 days corresponding values were 80.2 (129) and 54.7 (82), after 7 days 89.2 (187) (12.5) and 85.8 (208), after 14 days 47.1 (109.5) and 40.5 (116) after 28 days 23.1 (53.6) and 23.1 (48), and after 56 days 15.6 (26) and 15.3 (17). There was no significant difference in time trend between the two treatment groups (RMANOVA; p = 0.53). Baseline VA (logMAR) was 0.106 (0.241) in the vitamin group and 0.128 (0.456) in the placebo group. VA after 3 days was 0.236 (0.293) and 0.344 ( 0.489), after 7 days 0.204 (0.292) and 0.292 (0.479), after 14 days 0.162 (0.274) and 0.193 (0.454), after 28 days 0.096 (0.232) and 0.158 (0.436), and 0.026 (0.213) and 0.106 (0.437) after 56 days. Although no significant difference in time trend was detected, evaluation of the VA data of the last time point (56 days) by means of the Mann-Whitney test showed a significantly better VA in the vitamin group (p = 0.01).
CONCLUSIONS—There was no significant effect of vitamins C and E on laser flare measurements. The significant effect of the oral vitamins on visual acuity at 8 weeks after start of the oral vitamins C and E may indicate a protective effect in patients with acute anterior uveitis.

 PMID:10535857

  19. 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.

  20. Is the Grafted Tendon Shifted Anteriorly in the Femoral Tunnel at the Postremodeling Phase After Anterior Cruciate Ligament Reconstruction? A Clinical MRI Study

    PubMed Central

    Onodera, Jun; Yasuda, Kazunori; Masuda, Tetsuro; Tanabe, Yoshie; Kitamura, Nobuto; Yagi, Tomonori; Kondo, Eiji

    2017-01-01

    Background: Based on previous in vitro studies, it has been commonly believed that during anterior cruciate ligament (ACL) reconstruction with hamstring tendon, the grafted tendon is shifted anteriorly in the tunnel permanently after the graft is anchored to the tunnel wall. However, this has not been proven by in vivo studies. Hypothesis: At 1 year after anatomic double-bundle ACL reconstruction, the grafted tendons may not be shifted anteriorly in the femoral tunnel but anchored to the bony wall at the center of the tunnel. Study Design: Case series; Level of evidence, 4. Methods: Participants consisted of 40 patients who underwent anatomic double-bundle ACL reconstruction. The grafted tendons located in the femoral tunnel were examined 1 year after surgery using 2 different magnetic resonance imaging (MRI) protocols. In the first substudy, with 20 patients, the grafted tendon location was evaluated on an inclined sagittal multiplanar reconstruction (MPR) image taken using a standard T2-weighted protocol. In the second substudy with the remaining 20 patients, tendon location was evaluated on a pure axial MPR image taken using a VISTA (volume isotropic turbo spin echo acquisition) protocol. Results: On the inclined sagittal T2-weighted images of the anteromedial (AM) graft, the anterior width of the newly formed fibrous tissue, which surrounded the tendon graft, was significantly greater than the posterior width (P = .001). The center of the grafted tendon was slightly (mean, 2.5% of the tunnel diameter) but significantly (P = .0310) shifted posteriorly from the tunnel center. On the axial T2-VISTA images, the center of the AM graft was slightly but significantly shifted posteriorly (3.9%; P = .022) and medially (5.5%; P = .002) from the tunnel center. The center of the posterolateral (PL) graft was not significantly shifted to any direction from the center of the tunnel. Conclusion: The grafted tendons were not shifted anteriorly in the femoral tunnel 1 year

  1. Bundling of bacterial flagella

    NASA Astrophysics Data System (ADS)

    Powers, Thomas R.; van Parys, Annemarie J.; Breuer, Kenneth S.

    2002-03-01

    In bacterial chemotaxis, cells such as E. coli drift up chemical gradients by means of a directed random walk. Near the beginning of each step of a walk, the rotating helical flagella which propel the cell form a bundle. Using macroscopic experiments and numerical calculations, we study the viscous flows set up by two rotating helices. Our work illustrates the importance of geometry; for example, left-handed helices rotating counter-clockwise when viewed from the distal ends will inter-penetrate and synchronize when the pitch is shorter than the circumference. When the same helices turn clockwise, they fail to inter-penetrate.

  2. Bundle Formation in Polyelectrolyte Brushes

    NASA Astrophysics Data System (ADS)

    Günther, J. U.; Ahrens, H.; Förster, S.; Helm, C. A.

    2008-12-01

    Bundle formation of the vertically oriented polyelectrolytes within polyelectrolyte brushes is studied with x-ray reflectivity and grazing-incidence diffraction as a function of grafting density and ion concentration. At 0.8 Molar monomer concentration and without added salt, a bundle consists of two chains and is 50 Å long. On the addition of up to 1M CsCl, the aggregation number increases up to 15 whereas the bundle length approaches a limiting value, 20 Å. We suggest that the bundle formation is determined by a balance between long-ranged electrostatic repulsion, whose range and amplitude is decreased on salt addition, and short-ranged attraction.

  3. 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.

  4. 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.

  5. 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.

  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: (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.

  7. 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.

  8. Fiber bundle phase conjugate mirror

    DOEpatents

    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.

  9. Arthroscopic Control for Safe and Secure Seating of Suspensory Devices for Femoral Fixation in Anterior Cruciate Ligament Reconstruction Using Three Different Techniques

    PubMed Central

    Kang, Seo Goo; Lee, Yong Seuk

    2017-01-01

    Purpose The purpose of this study was to evaluate the efficacy of our technique that allows direct visualization of seating of suspensory devices in anterior cruciate ligament (ACL) reconstruction. Materials and Methods Three different suspensory devices (TightRope RT, RetroButton, and EndoButton) were used in ACL reconstruction using 3 different techniques (outside-in, anteromedial [AM] portal, and transtibial techniques). Positioning of a guiding material and seating pattern of the suspensory devices were evaluated according to the surgical technique and suspensory device used. Results On the transtibial technique, 21 of total 26 cases (81%) of single bundle reconstructions and 22 of total 22 cases (100%) of double bundle reconstructions required superolateral capsulotomy where buttons were found in 21 of total 21 cases (100%) and 17 of 22 cases (77%), respectively. On the AM portal technique, all patients required capsulotomy and the button was found in only 18 of total 32 cases (56%) even after capsulotomy. On the outside-in technique, all patients required capsulotomy and the button was found in 86 of total 86 cases (100%). Conclusions Our technique for direct visualization of seating of the suspensory devices was more effective in outside-in and single bundle transtibial ACL reconstruction. However, it was less effective in double bundle transtibial and AM portal ACL reconstructions. PMID:28231646

  10. 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.

  11. 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

  12. 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.

  13. 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

  14. Structure of the acrosomal bundle.

    PubMed

    Schmid, Michael F; Sherman, Michael B; Matsudaira, Paul; Chiu, Wah

    2004-09-02

    In the unactivated Limulus sperm, a 60- micro m-long bundle of actin filaments crosslinked by the protein scruin is bent and twisted into a coil around the base of the nucleus. At fertilization, the bundle uncoils and fully extends in five seconds to support a finger of membrane known as the acrosomal process. This biological spring is powered by stored elastic energy and does not require the action of motor proteins or actin polymerization. In a 9.5-A electron cryomicroscopic structure of the extended bundle, we show that twist, tilt and rotation of actin-scruin subunits deviate widely from a 'standard' F-actin filament. This variability in structural organization allows filaments to pack into a highly ordered and rigid bundle in the extended state and suggests a mechanism for storing and releasing energy between coiled and extended states without disassembly.

  15. Fabrication of electrospun nanofibers bundles

    NASA Astrophysics Data System (ADS)

    Ye, Junjun; Sun, Daoheng

    2007-12-01

    Aligned nanofibers, filament bundle composed of large number of nanofibers have potential applications such as bio-material, composite material etc. A series of electrospinning experiments have been conducted to investigate the electrospinning process,in which some parameters such as polymer solution concentration, bias voltage, distance between spinneret and collector, solution flow rate etc have been setup to do the experiment of nanofibers bundles construction. This work firstly reports electrospun nanofiber bundle through non-uniform electrical field, and nanofibers distributed in different density on electrodes from that between them. Thinner nanofibers bundle with a few numbers of nanofiber is collected for 3 seconds; therefore it's also possible that the addressable single nanofiber could be collected to bridge two electrodes.

  16. Atrio-His bundle tracts.

    PubMed Central

    Brechenmacher, C

    1975-01-01

    The atrio-His bundle tracts are very rare; only two have been found in 687 hearts studied histologically. These tracts have a similar appearance to those of the atrioventricular bundle and form a complete bypass of the atrioventricular node. In their presence the electrocardiogram may show a short or normal PR interval. They may be responsible for some cases of very rapid ventricular response to supraventricular arrhythmias. Images PMID:1191446

  17. Microstructure Variations in the Soft-Hard Tissue Junction of the Human Anterior Cruciate Ligament.

    PubMed

    Zhao, Lei; Lee, Peter V S; Ackland, David C; Broom, Neil D; Thambyah, Ashvin

    2017-09-01

    The role of the sub-bundles in the anterior cruciate ligament (ACL) has been defined, such that the anterior-medial bundle directly resists anterior tibial translation while the posterior lateral bundle is involved in rotational stability. With regards to this biomechanical function, much of the previous work on bundle-specific morphology has been carried out on the macroscale, with much less attention given to the micro-to-ultrastructural scalar levels. This is especially true of the enthesis and its microstructure, a biomechanically significant region that has been largely neglected in the published literature dealing with ACL sub-bundle anatomy. In this study, the human ACL tibial enthesis was investigated at multiple scalar levels using differential interference contrast and scanning electron microscopies with the aim of determining whether the sub-bundle ligament structure, and its known macroscale function, is consistent with its micro-architecture at the ligament-bone junction. The investigation found that different ligament insertion morphologies exist between the two bundles, where the AM bundle has more intense interdigitation with the bone matrix than that of the PL bundle. The results suggest that such structure-function relationships, especially across scalar-levels, provide new insight into the significance of the sub-bundle anatomy of the ACL. Anat Rec, 300:1547-1559, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  18. Connections on decorated path space bundles

    NASA Astrophysics Data System (ADS)

    Chatterjee, Saikat; Lahiri, Amitabha; Sengupta, Ambar N.

    2017-02-01

    For a principal bundle P → M equipped with a connection A ¯ , we study an infinite dimensional bundle PA¯ dec P over the space of paths on M, with the points of PA¯ dec P being horizontal paths on P decorated with elements of a second structure group. We construct parallel transport processes on such bundles and study holonomy bundles in this setting.

  19. Bundle Formation in Biomimetic Hydrogels.

    PubMed

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

    2016-08-08

    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.

  20. 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.

  1. Bundle Branch Reentrant Ventricular Tachycardia

    PubMed Central

    Mazur, Alexander; Kusniec, Jairo; Strasberg, Boris

    2005-01-01

    Bundle branch reentrant (BBR) tachycardia is an uncommon form of ventricular tachycardia (VT) incorporating both bundle branches into the reentry circuit. The arrhythmia is usually seen in patients with an acquired heart disease and significant conduction system impairment, although patients with structurally normal heart have been described. Surface ECG in sinus rhythm (SR) characteristically shows intraventricular conduction defects. Patients typically present with presyncope, syncope or sudden death because of VT with fast rates frequently above 200 beats per minute. The QRS morphology during VT is a typical bundle branch block pattern, usually left bundle branch block, and may be identical to that in SR. Prolonged His-ventricular (H-V) interval in SR is found in the majority of patients with BBR VT, although some patients may have the H-V interval within normal limits. The diagnosis of BBR VT is based on electrophysiological findings and pacing maneuvers that prove participation of the His- Purkinje system in the tachycardia mechanism. Radiofrequency catheter ablation of a bundle branch can cure BBR VT and is currently regarded as the first line therapy. The technique of choice is ablation of the right bundle. The reported incidence of clinically significant conduction system impairment requiring implantation of a permanent pacemaker varies from 0% to 30%. Long-term outcome depends on the underlying cardiac disease. Patients with poor systolic left ventricular function are at risk of sudden death or death from progressive heart failure despite successful BBR VT ablation and should be considered for an implantable cardiovertor-defibrillator. PMID:16943949

  2. Anterior temporal lobe white matter abnormal signal (ATLAS) as an indicator of seizure focus laterality in temporal lobe epilepsy: comparison of double inversion recovery, FLAIR and T2W MR imaging.

    PubMed

    Morimoto, Emiko; Kanagaki, Mitsunori; Okada, Tomohisa; Yamamoto, Akira; Mori, Nobuyuki; Matsumoto, Riki; Ikeda, Akio; Mikuni, Nobuhiro; Kunieda, Takeharu; Paul, Dominik; Miyamoto, Susumu; Takahashi, Ryosuke; Togashi, Kaori

    2013-01-01

    To investigate the diagnostic capability of anterior temporal lobe white matter abnormal signal (ATLAS) for determining seizure focus laterality in temporal lobe epilepsy (TLE) by comparing different MR sequences. This prospective study was approved by the institutional review board and written informed consent was obtained. Three 3D sequences (double inversion recovery (DIR), fluid-attenuated inversion recovery (FLAIR) and T2-weighted imaging (T2WI)) and two 2D sequences (FLAIR and T2WI) were acquired at 3 T. Signal changes in the anterior temporal white matter of 21 normal volunteers were evaluated. ATLAS laterality was evaluated in 21 TLE patients. Agreement of independent evaluations by two neuroradiologists was assessed using κ statistics. Differences in concordance between ATLAS laterality and clinically defined seizure focus laterality were analysed using McNemar's test with multiple comparisons. Pre-amygdala high signals (PAHS) were detected in all volunteers only on 3D-DIR. Inter-evaluator agreement was moderate to almost perfect for each sequence. Correct diagnosis of seizure laterality was significantly more frequent on 3D-DIR than on any other sequences (P ≤ 0.031 for each evaluator). The most sensitive sequence for detecting ATLAS laterality was 3D-DIR. ATLAS laterality on 3D-DIR can be a good indicator for determining seizure focus localization in TLE.

  3. Anterior cruciate ligament reconstruction practice patterns by NFL and NCAA football team physicians.

    PubMed

    Erickson, Brandon J; Harris, Joshua D; Fillingham, Yale A; Frank, Rachel M; Bush-Joseph, Charles A; Bach, Bernard R; Cole, Brian J; Verma, Nikhil N

    2014-06-01

    This study aimed to determine practice patterns for National Football League (NFL) and National Collegiate Athletic Association (NCAA) Division I football team orthopaedic surgeons regarding management of anterior cruciate ligament (ACL) tears in elite, young, and middle-aged recreational athletes. Two hundred sixty-seven NFL and NCAA Division I team orthopaedic surgeons were surveyed through an online survey. A 9-question survey assessed surgeon experience, graft choice, femoral tunnel drilling access, number of graft bundles, and rehabilitation after ACL reconstruction. One hundred thirty-seven team orthopaedic surgeons (51%) responded (mean experience 16.75 ± 8.7 years). Surgeons performed 82 ± 50 ACL reconstructions in 2012. One hundred eighteen surgeons (86%) would use bone-patellar tendon-bone (BPTB) autografts to treat their starting running backs. Ninety (67%) surgeons drill the femoral tunnel through an accessory anteromedial portal (26% through a transtibial portal). Only 1 surgeon prefers a double-bundle to a single-bundle reconstruction. Seventy-seven (55.8%) surgeons recommend waiting at least 6 months before return to sport, whereas 17 (12.3%) wait at least 9 months. No surgeon recommends waiting 12 months or more before return to sport. Eighty-eight (64%) surgeons do not recommend a brace for their starting running backs during sport once they return to play. BPTB is the most frequently used graft for ACL reconstruction by NFL and NCAA Division I team physicians in their elite-level running backs. Nearly all surgeons always use a single-bundle technique, and most do not recommend a brace on return to sport in running backs. Return to sport most commonly occurs at least 6 months postoperatively, with some surgeons requiring a normal examination and normal return-to-sport testing (single leg hop). Copyright © 2014 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  4. Procedure for dispersing fiber bundles

    NASA Technical Reports Server (NTRS)

    Padilla, D.

    1974-01-01

    Fiber bundles are dispersed and fibers are cleaned within enclosed container; therefore, safety clothing, masks, and eye protection are not required. Procedure also could be used wherever materials, such as fiberglass or insulation, require dispersion, fluffing, or cleaning. Process could be automated into continuous operation for handling large quantities of fiber.

  5. 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…

  6. 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.

  7. 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

  8. Thermal conversion of bundled carbon nanotubes into graphitic ribbons.

    PubMed

    Gutiérrez, H R; Kim, U J; Kim, J P; Eklund, P C

    2005-11-01

    High temperature heat treatment (HTT) of bundled single-walled carbon nanotubes (SWNTs) in vacuum ( approximately 10(-5) Torr) has been found to lead to the formation of two types of graphitic nanoribbons (GNRs), as observed by high-resolution transmission electron microscopy. Purified SWNT bundles were first found to follow two evolutionary steps, as reported previously, that is, tube coalescence (HTT approximately 1400 degrees C) and then massive bond rearrangement (HTT approximately 1600 degrees C), leading to the formation of bundled multiwall nanotubes (MWNTs) with 3-12 shells. At HTT > 1800 degrees C, we find that these MWNTs collapse into multishell GNRs. The first type of GNR we observed is driven by the collapse of diameter-doubled single-wall nanotubes, and their production is terminated at HTT approximately 1600 degrees C when the MWNTs also start to form. We propose that the collapse is driven by van der Waals forces between adjacent tubes in the same bundle. For HTT > 2000 degrees C, the heat-treated material is found to be almost completely in the multishell GNR form.

  9. Subroutine bundls, a fortran IV program to determine schreinemakers bundles

    NASA Astrophysics Data System (ADS)

    Linde, J.; Andrew, A. S.

    Given an entire set of relevant balanced equations, BUNDLS and associated subroutines select all invariant points and order univariant lines around these points. Invariant points are formed by taking every set of m absent phases from each reaction. All revelant univariant lines are ordered around each invariant point by a direct application of the rules of Schreinemakers. The program also calculates true angular values for PT, P-μ x1 or μ y-μ x diagrams.

  10. A bundle gerbe construction of a spinor bundle from the smooth free loop of a vector bundle

    NASA Astrophysics Data System (ADS)

    Ambler, Stuart

    A bundle gerbe is constructed from an oriented smooth vector bundle of even rank with a fiberwise inner product, over a compact connected orientable smooth manifold with Riemannian metric. From a trivialization of the bundle gerbe is constructed an irreducible Clifford module bundle, a spinor bundle over the smooth free loop space of the manifold. First, a Clifford algebra bundle over the loop space is constructed from the vector bundle. A polarization class bundle is constructed, choosing continuously over each point of the loop space a polarization class of Lagrangian subspaces of the complexification of the real vector space from which the Clifford algebra is made. Being unable to choose a Lagrangian subspace continuously from the polarization class over each point, the thesis constructs a bundle gerbe over the loop space of the base manifold to encode over each loop all such subspaces, along with the isomorphisms between the Fock spaces made from them, resulting from their being in the same polarization class. The vanishing of the Dixmier-Douady class of the bundle gerbe implies that the latter has a trivialization, from which is constructed a spinor bundle.

  11. Double dissociation of the anterior and posterior dorsomedial caudate-putamen in the acquisition and expression of associative learning with the nicotine stimulus.

    PubMed

    Charntikov, Sergios; Pittenger, Steven T; Swalve, Natashia; Li, Ming; Bevins, Rick A

    2017-07-15

    Tobacco use is the leading cause of preventable deaths worldwide. This habit is not only debilitating to individual users but also to those around them (second-hand smoking). Nicotine is the main addictive component of tobacco products and is a moderate stimulant and a mild reinforcer. Importantly, besides its unconditional effects, nicotine also has conditioned stimulus effects that may contribute to the tenacity of the smoking habit. Because the neurobiological substrates underlying these processes are virtually unexplored, the present study investigated the functional involvement of the dorsomedial caudate putamen (dmCPu) in learning processes with nicotine as an interoceptive stimulus. Rats were trained using the discriminated goal-tracking task where nicotine injections (0.4 mg/kg; SC), on some days, were paired with intermittent (36 per session) sucrose deliveries; sucrose was not available on interspersed saline days. Pre-training excitotoxic or post-training transient lesions of anterior or posterior dmCPu were used to elucidate the role of these areas in acquisition or expression of associative learning with nicotine stimulus. Pre-training lesion of p-dmCPu inhibited acquisition while post-training lesions of p-dmCPu attenuated the expression of associative learning with the nicotine stimulus. On the other hand, post-training lesions of a-dmCPu evoked nicotine-like responding following saline treatment indicating the role of this area in disinhibition of learned motor behaviors. These results, for the first time, show functionally distinct involvement of a- and p-dmCPu in various stages of associative learning using nicotine stimulus and provide an initial account of neural plasticity underlying these learning processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Evolution of growth modes for polyelectrolyte bundles.

    PubMed

    Lai, Ghee Hwee; Coridan, Rob; Zribi, Olena V; Golestanian, Ramin; Wong, Gerard C L

    2007-05-04

    Multivalent ions induce attractions between polyelectrolytes, but lead to finite-sized bundles rather than macroscopic phase separation. The kinetics of aggregation and bundle formation of actin is tracked using two different fluorescently labeled populations of F-actin. It is found that the growth mode of these bundles evolves with time and salt concentration, varying from an initial lateral growth to a longitudinal one at later stages. The results suggest that kinetics play a role in bundle growth, but not in the lateral size of bundles, which is constant for linear and branched topologies.

  13. Anatomic characteristics and radiographic references of the anterolateral and posteromedial bundles of the posterior cruciate ligament.

    PubMed

    Osti, Michael; Tschann, Peter; Künzel, Karl Heinz; Benedetto, Karl Peter

    2012-07-01

    Anatomic graft tunnel placement is reported to be essential in double-bundle posterior cruciate ligament (PCL) reconstruction. A measurement system that correlates anatomy and radiographs is lacking so far. To define the femoral and tibial attachments of the anterolateral (AL) and posteromedial (PM) bundles and to correlate them with digital and radiographic images to establish a radiographic anatomy based on anatomic landmarks and evaluate whether radiographs can serve as an accurate method for intraoperative and postoperative assessments of tunnel placement. Descriptive laboratory study. Fifteen human cadaveric knee specimens were used. After preparation, the insertion areas of the 2 fiber bundles were marked with colorants, and high-definition digital images were obtained. With radiopaque tubes placed in the center of each bundle's footprint, anteroposterior and lateral radiographs were created. A measurement grid system was superimposed to determine the position of the AL and PM bundles' femoral and tibial insertion areas on both digital images and radiographs. The measurement zones were numbered 1 to 16, starting in the anterosuperior corner and ending in the posteroinferior corner. On radiographs and digital images, the femoral centers of the AL and PM bundles were found in zones 2 and 7, respectively. The tibial centers of the AL and PM bundles were found at 47.88% and 50.93%, respectively, of the total mediolateral diameter, 83.09% and 92.29%, respectively, of the total anteroposterior diameter, and 3.53 mm and 8.57 mm, respectively, inferior from the tibial plateau on radiographs. This study provides a geometric characterization of the AL and PM bundles of the PCL and establishes a reliable and feasible correlation system between anatomy and radiography based on anatomic landmarks. Accurate definition of the insertion sites of the PCL is essential for anatomic double-bundle reconstruction. The results of our study may be used as a reference for

  14. Alpha 2 LASSO Data Bundles

    DOE Data Explorer

    Gustafson, William Jr; Vogelmann, Andrew; Endo, Satoshi; Toto, Tami; Xiao, Heng; Li, Zhijin; Cheng, Xiaoping; Kim, Jinwon; Krishna, Bhargavi

    2015-08-31

    The Alpha 2 release is the second release from the LASSO Pilot Phase that builds upon the Alpha 1 release. Alpha 2 contains additional diagnostics in the data bundles and focuses on cases from spring-summer 2016. A data bundle is a unified package consisting of LASSO LES input and output, observations, evaluation diagnostics, and model skill scores. LES input include 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.

  15. Reflooding of tight lattice bundles

    SciTech Connect

    Veteau, J.M.; Digonnet, A.; Deruaz, R. . Centre d'Etudes Nucleaires de Grenoble)

    1994-07-01

    Results regarding analytical bottom reflooding experiments in a 37- and a 127-heater rod bundle are presented for two different tight lattices. A comparison between these two geometries and with the standard pressurized water reactor (PWR) array shows a degradation of cooling efficiency when the cross section of the subchannels is decreased. The core heat sinks (guide thimbles and water tubes'') are seen to have a noticeable influence on the overall cooling of the bundle, and it is confirmed that a combined top/bottom injection does not significantly improve cooling efficiency. Calculations with CATHARE 1.3 code adjusted for the standard PWR array are presented (zero heat sinks), but results have to be confirmed over a wider range of parameters.

  16. 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

    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

    2016-08-05

    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. 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. to evaluate the effect of calcifediol on LV remodelling defined as an increase in LV end-diastolic volume ≥10% (MRI). 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. 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 Technical Requirements for Pharmaceuticals for Human Use - Good Clinical Practice (ICH

  17. 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

  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. A case report of different degrees of the left anterior, septal and posterior fascicular branch block.

    PubMed

    Sun, Huaqun; Hong, Yupeng; Jin, Tao

    2015-03-01

    We present a rare case of various conduction defects involving the left anterior, septal, and posterior branch in one patient. The different degrees of block of anterior, septal, and posterior fascicular of the left bundle branch indicate pathological changes in left ventricle. However, the values of this electrocardiographic presentation indicating the left ventricular function still need more investigations.

  20. Gauge transformations and fiber bundle theory

    NASA Astrophysics Data System (ADS)

    Socolovsky, M.

    1991-09-01

    The relationship between the group Γ of pure gauge transformations of Atiyah, Hitchin, and Singer [Proc. R. Soc. London Ser. A 362, 425 (1978)] of a principal fiber bundle and the group G of gauge transformations consisting of the direct product of the local gauge groups on the base space is studied. Γ is an invariant subgroup of G and the quotient G/Γ is identified with the group of inequivalent gauge transformations. In the framework of the category of principal fiber bundles with connections, a natural explanation for the relevance of the group Γ in the classical and quantum theories of gauge fields is presented. The paper is made self-contained by an introductory discussion of the concepts of principal coordinate fiber bundle (gauge fixed principal fiber bundle) and principal fiber bundle, and of the equivalence between the three different versions of the group of vertical automorphisms of the bundle.

  1. Bundled pipe speeds offshore laying

    SciTech Connect

    Brockbank, J. )

    1990-05-07

    Technology which allows pipelines to be installed in bundles is expediting pipelay operations in the North Sea. This paper reports how the piggyback system was recently used on 60 km of North Sea gas pipelines for three major projects. For 7 years the practice of installing two or more pipelines in one operation has become an established practice for North Sea offshore oil and gas projects. The technique, commonly referred to as a piggyback operation, reduces installation costs, improves operation reliability, and cuts maintenance time.

  2. Microtubule Bundling and Shape Transitions

    NASA Astrophysics Data System (ADS)

    Needleman, Daniel

    2005-03-01

    Microtubules (MTs) are hollow cylindrical polymers composed of heterodimers of the protein tubulin that align end-to-end in the MT wall, forming linear protofilaments that interact laterally. Placing MTs under osmotic pressure causes them to reversibly buckle to a noncircular shape and pack into rectangular bundles at a critical osmotic pressure; further increases in pressure continue to distort MTs elastically. At higher osmotic pressures stressing polymers may be forced into the MT lumen causing the MTs to revert to a circle cross-section and pack into hexagonal bundles. This SAXRD-osmotic stress study provides a probe of the inter-protofilament bond strength and gives insight into the mechanisms by which microtubule associated proteins and the cancer chemotherapeutic drug Taxol stabilize MTs. We present further measurements of the mechanical properties of MT walls, MT-MT interactions, and the entry of polymers into the microtubule lumen. Supported by NSF DMR- 0203755, NIH GM-59288 and NS-13560, and CTS-0103516. SSRL is supported by the U.S. DOE.

  3. 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

  4. Are central line bundles and ventilator bundles effective in critically ill neonates and children?

    PubMed

    Smulders, Charlotte A; van Gestel, Josephus P J; Bos, Albert P

    2013-08-01

    Central line-associated bloodstream infections (CLABSI) and ventilator-associated pneumonia (VAP) are common problems in adult, pediatric (PICU) and neonatal (NICU) intensive care unit patients. Care bundles have been developed to prevent these hospital-acquired infections and to provide best possible care. Studies in adults have proven that care bundles contribute to a decrease in CLABSI and VAP rates. The purpose of this literature review was to critically appraise the known evidence of the effectiveness of central line bundles and ventilator bundles in PICU and NICU patients. The number of publications of central line bundles and ventilator bundles in PICU and NICU patients is limited compared to adults. Ten studies in PICU patients demonstrated a significant decrease in the CLABSI or VAP rate after implementation of the bundle. Two studies in neonates demonstrated a reduction in the CLABSI rate after implementation of the central line bundle. No studies on the effectiveness of the ventilator bundle in neonates were found. Bundle elements differed between studies, and their scientific basis was not as robust as in adults. Monitoring of compliance to bundle elements seems required for optimal reduction of CLABSI and VAP. Bundle components that focus on maintenance of a central line probably are important to prevent CLABSI in children.

  5. His bundle recordings in bradycardia-dependent AV block induced by premature beats.

    PubMed Central

    Castellanos, A; Khuddus, S A; Sommer, L S; Sung, R J; Myerburg, R J

    1975-01-01

    Symptomatic bradycardia-independent atrioventricular block occurred in a patient with right bundle-branch block, left anterior hemiblock, and prolonged HV interval. The arrhythmia, triggered by a spontaneous or induced premature beats, appeared when the post-extrasystolic PP and HH intervals increased to a critical value. Reinitiation of atrioventricular conduction required the presence of ventricular escapes. Bradycardia-dependent atrioventricular block was related to either an enhanced or slightly rising slope of diastolic depolarization, or to a decrease in membrane responsiveness. The patient also, most probably, had tachycardia-dependent atrioventricular block. Both types of conduction disturbance occurred in the same part of the intraventricular conducting system, either in the low His bundle or left bundle-branch or its posteroinferior division. It is suggested that the electrophysiological study of cases with prolonged HV intervals should include procedures which can expose bradycardia-dependent atrioventricular block. PMID:1148054

  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. 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.

  8. 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.

  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. 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.

  11. Critical heat flux predictions in rod bundles

    SciTech Connect

    Kao, S.P.; Kazimi, M.S.

    1983-01-01

    The prediction of critical heat flux (CHF) in rod bundles has been studied with both subchannel and bundle-average methods. The correlations of Biasi, Bowring, CISE-4, and Barnett were considered. The General Electric 9-rod bundle CHF data were used in the comparisons. Calculations were performed by the two-fluid subchannel code THERMIT-2. The results indicate that the subchannel method yields more conservative CHF predictions than the bundleaverage method. This is attributed to the two-phase turbulent mixing phenomenon in the bundle, which can be modeled only on a subchannel basis. The results also indicate that the CISE-4 correlation had the smallest error in prediction of transition boiling for both subchannel and bundle-average methods.

  12. Predictors of Revision Surgery After Primary Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Yabroudi, Mohammad A.; Björnsson, Haukur; Lynch, Andrew D.; Muller, Bart; Samuelsson, Kristian; Tarabichi, Majd; Karlsson, Jón; Fu, Freddie H.; Harner, Christopher D.; Irrgang, James J.

    2016-01-01

    Background: Revision anterior cruciate ligament (ACL) reconstruction surgery occurs in 5% to 15% of individuals undergoing ACL reconstruction. Identifying predictors for revision ACL surgery is of essence in the pursuit of creating adequate prevention programs and to identify individuals at risk for reinjury and revision. Purpose: To determine predictors of revision ACL surgery after failed primary ACL reconstruction. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 251 participants (mean age ± SD, 26.1 ± 9.9 years) who had undergone primary ACL reconstruction 1 to 5 years earlier completed a comprehensive survey to determine predictors of revision ACL surgery at a mean 3.4 ± 1.3 years after the primary ACL reconstruction. Potential predictors that were assessed included subject characteristics (age at the time of surgery, time from injury to surgery, sex, body mass index, preinjury activity level, return to sport status), details of the initial injury (mechanism; concomitant injury to other ligaments, menisci, and cartilage), surgical details of the primary reconstruction (Lachman and pivot shift tests under anesthesia, graft type, femoral drilling technique, reconstruction technique), and postoperative course (length of rehabilitation, complications). Univariate and multivariate logistic regression analyses were performed to identify factors that predicted the need for revision ACL surgery. Results: Overall, 21 (8.4%) subjects underwent revision ACL surgery. Univariate analysis showed that younger age at the time of surgery (P = .003), participation in sports at a competitive level (P = .023), and double-bundle ACL reconstruction (P = .024) predicted increased risk of revision ACL surgery. Allograft reconstructions also demonstrated a trend toward greater risk of revision ACL surgery (P = .076). No other variables were significantly associated with revision ACL surgery. Multivariate analysis revealed that revision ACL surgery was

  13. Anatomical two-bundle versus Rosenberg's isometric bi-socket ACL reconstruction: a biomechanical comparison in laxity match pretension.

    PubMed

    Mae, Tatsuo; Shino, Konsei; Matsumoto, Norinao; Hamada, Masayuki; Yoneda, Minoru; Nakata, Ken

    2007-04-01

    It is not well known how much tension should be applied to ACL graft at the time of graft fixation. As a step to determine the optimal initial tension, it is indispensable to know the graft tension to restore normal anterior-posterior (A-P) laxity (laxity match pretension, LMP). The objective was to determine the LMP in ACL reconstruction for the anatomical two-bundle technique and for the Rosenberg's isometric bi-socket one, and to compare these two techniques in LMP. Twenty-four patients with unilateral chronic ACL insufficiency were divided into the following two groups. The anatomical two-bundle technique was performed on 12 patients via two femoral tunnels at 9 and 10 o'clock or 2 and 3 o'clock on the posterior margin of the notch and two tibial tunnels (Group A), while the Rosenberg's isometric bi-socket reconstruction was performed on the remaining 12 patients through two femoral tunnels at 10 and 11 o'clock or 1 and 2 o'clock and one wider tibial tunnel (Group B). After two doubled semitendinosus grafts were fixed with two EndoButton-CL s on the femur, they were temporarily fixed to the tension-adjustable force gauge on the tibia, respectively. The total tension applied to grafts was set at 10, 20, 30, 40, or 50 N at 20 degrees of knee flexion, and the A-P laxity was measured by applying A-P drawer load of 134 N at 20 degrees of flexion. By comparing the measured laxity with that for the opposite healthy knee, the tension to restore the normal A-P laxity (LMP) was estimated. The mean LMP of 7.3 N in Group A was significantly smaller than that of 25.8 N in Group B. The anatomical two-bundle technique makes it possible to more effectively restore A-P stability with lower initial tension than the isometric Rosenberg's bi-socket reconstruction.

  14. 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.

  15. Validation of fuel bundle mechanical performance code ETOILE with bundle/duct interaction experimental data

    SciTech Connect

    Nakagawa, Masatoshi )

    1993-04-01

    Validation of the ETOILE code through a comparison with experimental bundle/duct interaction (BDI) data is discussed. ETOILE is a newly developed three-dimensional finite element program that uses a new analytical method to predict distortions and mechanical behavior in wire-wrapped-type fuel-pin bundles during irradiation in liquid-metal fast breeder reactor cores. Comparisons between the ETOILE solutions and the experimental data for bundle stiffnesses and minimum pin-to-pin and pin-to-duct clearances under bundle compression suggest that BDI performance can be predicted reasonably well with a suitable choice of friction coefficient and initial spiral wire displacement. Application of the code in the analysis of the mechanical behavior of soft bundles with distributed wireless pins is also presented to demonstrate the effectiveness of this design in reducing the interaction forces between a fuel-pin bundle and a duct wall under bundle compression. Agreement with the experimental data is fairly good for the reduction in bundle stiffness when the configuration is changed from the normal bundle to the soft bundle.

  16. 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.

  17. Effective diffusion on Riemannian fiber bundles

    NASA Astrophysics Data System (ADS)

    Valdes, Carlos Valero

    2015-02-01

    The purpose of this paper is to provide equations to model the evolution of effective diffusion over a Riemannian fiber bundle (under the hypothesis of infinite diffusion rate along compact fibers). These equations are obtained by projecting the diffusion equation onto the base manifold of the fiber bundle. The projection (or dimensional reduction) is achieved by integrating the diffusion equation along the fibers of the bundle. This work generalizes an put into a general framework previous work on effective diffusion over channels and the interfaces between curved surfaces.

  18. Noncommutative Circle Bundles and New Dirac Operators

    NASA Astrophysics Data System (ADS)

    Dąbrowski, Ludwik; Sitarz, Andrzej

    2013-02-01

    We study spectral triples over noncommutative principal U(1) bundles. Basing on the classical situation and the abstract algebraic approach, we propose an operatorial definition for a connection and compatibility between the connection and the Dirac operator on the total space and on the base space of the bundle. We analyze in details the example of the noncommutative three-torus viewed as a U(1) bundle over the noncommutative two-torus and find all connections compatible with an admissible Dirac operator. Conversely, we find a family of new Dirac operators on the noncommutative tori, which arise from the base-space Dirac operator and a suitable connection.

  19. PDGF-alpha receptor and myelin basic protein mRNAs are not coexpressed by oligodendrocytes in vivo: a double in situ hybridization study in the anterior medullary velum of the neonatal rat.

    PubMed

    Butt, A M; Hornby, M F; Ibrahim, M; Kirvell, S; Graham, A; Berry, M

    1997-01-01

    Platelet-derived growth factor (PDGF) is a growth-regulatory dimer with A and B subunits. PDGF-AA, acting via PDGF receptors of the alpha-unit subtype (PDGF-alphaR), is implicated in the differentiation of oligodendrocyte precursors and in the survival of newly formed oligodendrocytes, which gradually lose expression of PDGF-alphaR. However, it is unclear whether terminally differentiated oligodendrocytes express PDGF-alphaR in vivo. To address this question, and to help clarify the role of PDGF-AA in late oligodendrocyte differentiation, we have used double in situ hybridization with digoxigenin- and fluorescein-labeled riboprobes to relate PDGF-alphaR mRNA and myelin basic protein (MBP) mRNA expression in the isolated intact anterior medullary velum (AMV) of rats ages Postnatal Day (P) 10-12 and P30-32. In parallel experiments, AMV were immunolabeled with the oligodendrocyte-specific monoclonal antibody Rip to provide information on oligodendrocyte development and the extent of myelination. At P10, the AMV contained tracts in which axons ranged from unmyelinated to fully myelinated, whereas myelination was complete in P30-32 AMV. The first oligodendrocytes to express MBP mRNA or Rip were promyelinating oligodendrocytes, which had a "star-burst" morphology and had not yet begun to form myelin sheaths. As myelination proceeded, MBP mRNA became dispersed throughout oligodendrocyte units, comprising cell somata, processes, and internodal myelin sheaths. By P30-32, MBP mRNA had been redistributed to the myelin sheaths only, reflecting a change in the site of protein synthesis in mature myelinated axon tracts. At no stage of oligodendrocyte differentiation did we observe cellular coexpression of mRNA for PDGFalphaR and MBP. Our results indicated that oligodendrocytes lost the expression of PDGFalphaR prior to gaining that of myelin gene products, and preclude an action of PDGF-AA on Rip+/MBP+ star-burst promyelinating oligodendrocytes. The spatial and temporal

  20. 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.

  1. SU(5) heterotic Standard Model bundles

    NASA Astrophysics Data System (ADS)

    Andreas, Björn; Hoffmann, Norbert

    2012-04-01

    We construct a class of stable SU(5) bundles on an elliptically fibered Calabi-Yau threefold with two sections, a variant of the ordinary Weierstrass fibration, which admits a free involution. The bundles are invariant under the involution, solve the topological constraint imposed by the heterotic anomaly equation and give three generations of Standard Model fermions after symmetry breaking by Wilson lines of the intermediate SU(5) GUT-group to the Standard Model gauge group. Among the solutions we find some which can be perturbed to solutions of the Strominger system. Thus these solutions provide a step toward the construction of phenomenologically realistic heterotic flux compactifications via non-Kähler deformations of Calabi-Yau geometries with bundles. This particular class of solutions involves a rank two hidden sector bundle and does not require background fivebranes for anomaly cancellation.

  2. 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.

  3. Cross Flow Boiling in Tube Bundles.

    DTIC Science & Technology

    1982-10-01

    subsequent corrosion induced failure of the heating tube , an understanding of the fluid motion and heat transfer behavior in confined spaces will be...1-1982A U Cross Flowing Boiling in Tube Bundles Annual Technical Report October 1982 LOD S.C. Yao Associate Professor Department of Mechanical...Subtitle) S. TYPE OF REPORT & PERIOD COVERED Annual Technical Report CROSS FLOW BOILING IN TUBE BUNDLES Aug. 1, 1981 to Aug. 1, 1982 - 6. PERFORMING ORG

  4. Torsional Behavior of Axonal Microtubule Bundles

    PubMed Central

    Lazarus, Carole; Soheilypour, Mohammad; Mofrad, Mohammad R.K.

    2015-01-01

    Axonal microtubule (MT) bundles crosslinked by microtubule-associated protein (MAP) tau are responsible for vital biological functions such as maintaining mechanical integrity and shape of the axon as well as facilitating axonal transport. Breaking and twisting of MTs have been previously observed in damaged undulated axons. Such breaking and twisting of MTs is suggested to cause axonal swellings that lead to axonal degeneration, which is known as “diffuse axonal injury”. In particular, overstretching and torsion of axons can potentially damage the axonal cytoskeleton. Following our previous studies on mechanical response of axonal MT bundles under uniaxial tension and compression, this work seeks to characterize the mechanical behavior of MT bundles under pure torsion as well as a combination of torsional and tensile loads using a coarse-grained computational model. In the case of pure torsion, a competition between MAP tau tensile and MT bending energies is observed. After three turns, a transition occurs in the mechanical behavior of the bundle that is characterized by its diameter shrinkage. Furthermore, crosslink spacing is shown to considerably influence the mechanical response, with larger MAP tau spacing resulting in a higher rate of turns. Therefore, MAP tau crosslinking of MT filaments protects the bundle from excessive deformation. Simultaneous application of torsion and tension on MT bundles is shown to accelerate bundle failure, compared to pure tension experiments. MAP tau proteins fail in clusters of 10–100 elements located at the discontinuities or the ends of MT filaments. This failure occurs in a stepwise fashion, implying gradual accumulation of elastic tensile energy in crosslinks followed by rupture. Failure of large groups of interconnecting MAP tau proteins leads to detachment of MT filaments from the bundle near discontinuities. This study highlights the importance of torsional loading in axonal damage after traumatic brain injury

  5. Is It Complete Left Bundle Branch Block? Just Ablate the Right Bundle.

    PubMed

    Ali, Hussam; Lupo, Pierpaolo; Foresti, Sara; De Ambroggi, Guido; Epicoco, Gianluca; Fundaliotis, Angelica; Cappato, Riccardo

    2017-03-01

    Complete left bundle branch block (LBBB) is established according to standard electrocardiographic criteria. However, functional LBBB may be rate-dependent or can perpetuate during tachycardia due to repetitive concealed retrograde penetration of impulses through the contralateral bundle "linking phenomenon." In this brief article, we present two patients with basal complete LBBB in whom ablating the right bundle unmasked the actual antegrade conduction capabilities of the left bundle. These cases highlight intriguing overlap between electrophysiological concepts of complete block, linking, extremely slow, and concealed conduction.

  6. Hierarchical Assembly of a Dual-responsive Macroscopic Insulated Molecular Wire Bundle in a Gradient System

    PubMed Central

    Sheng, Yujie; Chen, Qibin; Yao, Junyao; Wang, Ying; Liu, Honglai

    2015-01-01

    Here, we report the hierarchical self-assembly of a cationic gemini amphiphile, Azo 1, in a composition gradient solution generated using solvent evaporation. As the gradient solution is formed, Azo 1 forms nanorods in the lower region of the solution. Depending on solvent composition, these nanorods can further develop into nanofibres, which can then intertwine to form double helices and other types of nanohelices in the upper region of the solution. Finally, a macroscopic wire bundle is formed via the fusion of nanohelices; this ribbon-like bundle exhibits elasticity and linear ohmic resistance properties. More intriguingly, this bundle exhibits photoresponsive properties that affect its deformation and conductivity, as well as a rapid electroresponse that affects its conductivity, indicating that it is feasible to control the charge pathway. PMID:25588881

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

    PubMed

    Hirano, Mayumi; Hirano, Katsuya

    2016-02-11

    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.

  8. 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

  9. 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.

  10. Buckling behavior of individual and bundled microtubules.

    PubMed

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

    2015-04-07

    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

  11. The histology of retinal nerve fiber layer bundles and bundle defects.

    PubMed

    Radius, R L; Anderson, D R

    1979-05-01

    The fiber bundle striations recognized clinically in normal monkey eyes appear to be bundles of axons compartmentalized within glial tunnels formed by Müller's-cell processes, when viewed histologically. The dark boundaries that separate individual bundles are the broadened foot endings of these cells near the inner surface of the retina. Within one week after focal retinal photocoagulation, characteristic fundus changes could be seen in experimental eyes. In histologic sections of the involved retina, there was marked cystic degeneration of the retinal nerve fiber layer. Within one month, atrophy of distal axon segments was complete. With the drop-out of damaged axons and thinning of individual fiber bundles, retinal striations became less prominent. The resulting fundus picture in these experimental eyes is similar to fiber bundle defects that can be seen clinically in various neuro-ophthalmic disorders.

  12. UNUSUAL MICROTUBULAR PATTERNS AND THREE-DIMENSIONAL MOVEMENT OF MEALYBUG SPERM AND SPERM BUNDLES

    PubMed Central

    Ross, Jean; Robison, W. Gerald

    1969-01-01

    The spermatozoon of the mealybug Pseudococcus obscurus Essig is a filamentous cell (0.25 µ by 300 µ) 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 µ 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 µ by 750 µ 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

  13. 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.

  14. Spectral bundles and the DRY-Conjecture

    NASA Astrophysics Data System (ADS)

    Andreas, Björn; Curio, Gottfried

    2012-04-01

    Supersymmetric heterotic string models, built from a Calabi-Yau threefold X endowed with a stable vector bundle V, usually start from a phenomenologically motivated choice of a bundle Vv in the visible sector, the spectral cover construction on an elliptically fibered X being a prominent example. The ensuing anomaly mismatch between c2(Vv) and c2(X), or rather the corresponding differential forms, is often 'solved', on the cohomological level, by including a fivebrane. This leads to the question whether the difference can be alternatively realized by a further stable bundle. The 'DRY'-conjecture of Douglas, Reinbacher and Yau in math.AG/0604597 gives a sufficient condition on cohomology classes on X to be realized as the Chern classes of a stable sheaf. In 1010.1644 [hep-th], we showed that infinitely many classes on X exist for which the conjecture is true. In this note, we give the sufficient condition for the mentioned fivebrane classes to be realized by a further stable bundle in the hidden sector. Using a result obtained in 1011.6246 [hep-th], we show that corresponding bundles exist, thereby confirming this version of the DRY-Conjecture.

  15. The NEtherlands Cervical Kinematics (NECK) Trial. Cost-effectiveness of anterior cervical discectomy with or without interbody fusion and arthroplasty in the treatment of cervical disc herniation; a double-blind randomised multicenter study

    PubMed Central

    2010-01-01

    Background Patients with cervical radicular syndrome due to disc herniation refractory to conservative treatment are offered surgical treatment. Anterior cervical discectomy is the standard procedure, often in combination with interbody fusion. Accelerated adjacent disc degeneration is a known entity on the long term. Recently, cervical disc prostheses are developed to maintain motion and possibly reduce the incidence of adjacent disc degeneration. A comparative cost-effectiveness study focused on adjacent segment degeneration and functional outcome has not been performed yet. We present the design of the NECK trial, a randomised study on cost-effectiveness of anterior cervical discectomy with or without interbody fusion and arthroplasty in patients with cervical disc herniation. Methods/Design Patients (age 18-65 years) presenting with radicular signs due to single level cervical disc herniation lasting more than 8 weeks are included. Patients will be randomised into 3 groups: anterior discectomy only, anterior discectomy with interbody fusion, and anterior discectomy with disc prosthesis. The primary outcome measure is symptomatic adjacent disc degeneration at 2 and 5 years after surgery. Other outcome parameters will be the Neck Disability Index, perceived recovery, arm and neck pain, complications, re-operations, quality of life, job satisfaction, anxiety and depression assessment, medical consumption, absenteeism, and costs. The study is a randomised prospective multicenter trial, in which 3 surgical techniques are compared in a parallel group design. Patients and research nurses will be kept blinded of the allocated treatment for 2 years. The follow-up period is 5 years. Discussion Currently, anterior cervical discectomy with fusion is the golden standard in the surgical treatment of cervical disc herniation. Whether additional interbody fusion or disc prothesis is necessary and cost-effective will be determined by this trial. Trial Registration Netherlands

  16. 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.

  17. 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

  18. Modulating Sound with Acoustic Metafiber Bundles.

    PubMed

    Xia, Jian-Ping; Sun, Hong-Xiang; Yuan, Shou-Qi

    2017-08-15

    Acoustic metamaterials and metasurfaces provide great flexibility for manipulating sound waves and promise unprecedented functionality, ranging from transformation acoustics, acoustic cloaking, acoustic imaging to acoustic rerouting. However, the design of artificial structures with both broad bandwidth and multifunctionality remains challenging with traditional design approaches. Here we present a design and realization of a broadband acoustic metafiber bundle. Very different from previously reported acoustic metamaterials and metasurfaces, not only the metafiber structure is simple, flexible and tunable, but also the metafiber bundle has the advantages of broad bandwidth, high transmission, no resonance-induced energy loss and unchangeable output wavefront owing to eigenmodes in the passbands of the metafiber. Besides, it could also achieve arbitrary complex modulations of cylindrical and plane acoustic wavefronts. The metafiber bundles realize the exciting multifunctionality of both acoustic metamaterials and metasurfaces in a broad frequency range, which provides diverse routes to design novel acoustic devices with versatile applications.

  19. 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.

  20. Contour based object detection using part bundles

    PubMed Central

    Lu, ChengEn; Adluru, Nagesh; Ling, Haibin; Zhu, Guangxi; Latecki, Longin Jan

    2016-01-01

    In this paper we propose a novel framework for contour based object detection from cluttered environments. Given a contour model for a class of objects, it is first decomposed into fragments hierarchically. Then, we group these fragments into part bundles, where a part bundle can contain overlapping fragments. Given a new image with set of edge fragments we develop an efficient voting method using local shape similarity between part bundles and edge fragments that generates high quality candidate part configurations. We then use global shape similarity between the part configurations and the model contour to find optimal configuration. Furthermore, we show that appearance information can be used for improving detection for objects with distinctive texture when model contour does not sufficiently capture deformation of the objects.

  1. 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.

  2. 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.

  3. The turtle thalamic anterior entopeduncular nucleus shares connectional and neurochemical characteristics with the mammalian thalamic reticular nucleus.

    PubMed

    Kenigfest, Natalia; Belekhova, Margarita; Repérant, Jacques; Rio, Jean Paul; Ward, Roger; Vesselkin, Nikolai

    2005-10-01

    Neurochemical and key connectional characteristics of the anterior entopeduncular nucleus (Enta) of the turtle (Testudo horsfieldi) were studied by axonal tracing techniques and immunohistochemistry of parvalbumin, gamma-aminobutyric acid (GABA) and glutamic acid decarboxylase (GAD). We showed that the Enta, which is located within the dorsal peduncle of the lateral forebrain bundle (Pedd), has roughly topographically organized reciprocal connections with the dorsal thalamic visual nuclei, the nucleus rotundus (Rot) and dorsal lateral geniculate nucleus (GLd). The Enta receives projections from visual telencephalic areas, the anterior dorsal ventricular ridge and dorsolateral cortex/pallial thickening. Most Enta neurons contained GABA and parvalbumin, and some of them were retrogradely labeled when the tracer was injected into the visual dorsal thalamic nuclei. Further experiments using double immunofluorescence revealed colocalization of GAD and parvalbumin in the vast majority of Enta neurons, and many of these cells showed retrograde labeling with Fluoro-gold injected into the Rot and/or GLd. According to these data, the Enta may be considered as a structural substrate for recurrent inhibition of the visual thalamic nuclei. Based on morphological and neurochemical similarity of the turtle Enta, caiman Pedd nucleus, the superior reticular nucleus in birds, and the thalamic reticular nucleus in mammals, we suggest that these structures represent a characteristic component which is common to the thalamic organization in amniotes.

  4. Unified Bundling and Registration of Brain White Matter Fibers

    PubMed Central

    Xu, Qing; Anderson, Adam W.; Gore, John C.

    2011-01-01

    Magnetic resonance diffusion tensor imaging is being widely used to reconstruct brain white matter fiber tracts. To characterize structural properties of the tracts, reconstructed fibers are often grouped into bundles that correspond to coherent anatomic structures. For further group analysis of fiber bundles, it is desirable that corresponding bundles from different studies are coregistered. To address these needs simultaneously, a unified fiber bundling and registration (UFIBRE) framework is proposed in this work. The framework is based on maximizing a posteriori Bayesian probabilities using an expectation maximization algorithm. Given a set of segmented template bundles and a whole-brain target fiber set, the UFIBRE algorithm optimally bundles the target fibers and registers them with the template. The bundling component in the UFIBRE algorithm simplifies fiber-based registration into bundle-to-bundle registration, and the registration component in turn guides the bundling process to find bundles consistent with the template. Experiments with in vivo data demonstrate that the estimated bundles have an ∼80% consistency with ground truth and the root mean square error between their bundle medial axes is less than one voxel. The proposed algorithm is highly efficient, offering potential routine use for group analysis of white matter fibers. PMID:19336300

  5. 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.

  6. 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.

  7. Bilateral Anterior Shoulder Dislocation

    PubMed Central

    Siu, Yuk Chuen; Lui, Tun Hing

    2014-01-01

    Introduction: Unilateral anterior shoulder dislocation is one of the most common problems encountered in orthopedic practice. However, simultaneous bilateral anterior dislocation of the shoulders is quite rare. Case Presentation: We report a case of a 75-year-old woman presented with simultaneous bilateral anterior shoulder dislocation following a trauma, complicated with a traction injury to the posterior cord of the brachial plexus. Conclusions: Bilateral anterior shoulder dislocation is very rare. The excessive traction force during closed reduction may lead to nerve palsy. Clear documentation of neurovascular status and adequate imaging before and after a reduction should be performed. PMID:25685749

  8. Laughter-induced left bundle branch block.

    PubMed

    Chow, Grant V; Desai, Dipan; Spragg, David D; Zakaria, Sammy

    2012-10-01

    We present the case of a patient with ischemic heart disease and intermittent left bundle branch block, reproducibly induced by laughter. Following treatment of ischemia with successful deployment of a drug-eluting stent, no further episodes of inducible LBBB were seen. Transient ischemia, exacerbated by elevated intrathoracic pressure during laughter, may have contributed to onset of this phenomenon.

  9. Meromorphic Higgs bundles and related geometries

    NASA Astrophysics Data System (ADS)

    Dalakov, Peter

    2016-11-01

    The present note is mostly a survey on the generalised Hitchin integrable system and moduli spaces of meromorphic G-Higgs bundles. We also fill minor gaps in the existing literature, outline a calculation of the infinitesimal period map and review some related geometries.

  10. Fluxes, bundle gerbes and 2-Hilbert spaces

    NASA Astrophysics Data System (ADS)

    Bunk, Severin; Szabo, Richard J.

    2017-10-01

    We elaborate on the construction of a prequantum 2-Hilbert space from a bundle gerbe over a 2-plectic manifold, providing the first steps in a programme of higher geometric quantisation of closed strings in flux compactifications and of M5-branes in C-fields. We review in detail the construction of the 2-category of bundle gerbes and introduce the higher geometrical structures necessary to turn their categories of sections into 2-Hilbert spaces. We work out several explicit examples of 2-Hilbert spaces in the context of closed strings and M5-branes on flat space. We also work out the prequantum 2-Hilbert space associated with an M-theory lift of closed strings described by an asymmetric cyclic orbifold of the SU(2) WZW model, providing an example of sections of a torsion gerbe on a curved background. We describe the dimensional reduction of M-theory to string theory in these settings as a map from 2-isomorphism classes of sections of bundle gerbes to sections of corresponding line bundles, which is compatible with the respective monoidal structures and module actions.

  11. Mobility of Taxol in Microtubule Bundles

    NASA Astrophysics Data System (ADS)

    Ross, J.

    2003-06-01

    Mobility of taxol inside microtubules was investigated using fluorescence recovery after photobleaching (FRAP) on flow-aligned bundles. Bundles were made of microtubules with either GMPCPP or GTP at the exchangeable site on the tubulin dimer. Recovery times were sensitive to bundle thickness and packing, indicating that taxol molecules are able to move laterally through the bundle. The density of open binding sites along a microtubule was varied by controlling the concentration of taxol in solution for GMPCPP samples. With > 63% sites occupied, recovery times were independent of taxol concentration and, therefore, inversely proportional to the microscopic dissociation rate, k_{off}. It was found that 10*k_{off} (GMPCPP) ~ k_{off} (GTP), consistent with, but not fully accounting for, the difference in equilibrium constants for taxol on GMPCPP and GTP microtubules. With < 63% sites occupied, recovery times decreased as ~ [Tax]^{-1/5} for both types of microtubules. We conclude that the diffusion of taxol along the microtubule interior is hindered by rebinding events when open sites are within ~7 nm of each other.

  12. 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…

  13. Bundled preparation of skin antisepsis decreases the risk of cardiac implantable electronic device-related infection.

    PubMed

    Chen, Huang-Chung; Chen, Mien-Cheng; Chen, Yung-Lung; Tsai, Tzu-Hsien; Pan, Kuo-Li; Lin, Yu-Sheng

    2016-06-01

    To evaluate the efficacy of bundled skin antiseptic preparation to prevent cardiac implantable electronic device (CIED) infections. From January 2010 to November 2013, 665 consecutive patients were divided into two groups according to the strategy of skin preparation. In Period 1 (January 2010 to June 2012), 395 patients received the standard skin antiseptic preparation. In Period 2 (July 2012 to November 2013), 270 patients received a triple-step skin antiseptic preparation, 'bundled skin antiseptic preparation', consisting of applying 75% alcohol over anterior chest on the night before the index day, povidone-iodine 10 min before operation, and the standard skin antiseptic preparation before incision. During follow-up, the occurrence of CIED infection was recorded. Multiple logistic regression analysis was used to determinate the risk factors of CIED infection. During a mean follow-up of 26.9 ± 16.2 months, 20 episodes of CIED infection developed in 19 patients (2.9%), and the incidence of minor and major infection episodes was 2.2% and 0.8%, respectively. Patients with the bundled skin antiseptic preparation had a significantly lower incidence of CIED infection, compared with patients with the standard preparation (0.7 vs. 4.3%, P = 0.007). In multivariate analysis, pocket haematoma (P = 0.020), atrial fibrillation (P = 0.033), and complex procedures (P = 0.047) were independent predictors for CIED infection. In contrast, the bundled skin antiseptic preparation was a significant predictor against CIED infection (P = 0.014). Pocket haematoma was the most important risk factor for CIED infection. The bundled skin antiseptic preparation strategy significantly reduced the risk of minor CIED infection. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  14. 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

  15. 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.

  16. Computational models of hair cell bundle mechanics: III. 3-D utricular bundles.

    PubMed

    Silber, Joe; Cotton, John; Nam, Jong-Hoon; Peterson, Ellengene H; Grant, Wally

    2004-11-01

    Six utricular hair bundles from a red-eared turtle are modeled using 3-D finite element analysis. The mechanical model includes shear deformable stereocilia, realignment of all forces during force load increments, and tip and lateral link inter-stereocilia connections. Results show that there are two distinct bundle types that can be separated by mechanical bundle stiffness. The more compliant group has fewer total stereocilia and short stereocilia relative to kinocilium height; these cells are located in the medial and lateral extrastriola. The stiff group are located in the striola. They have more stereocilia and long stereocilia relative to kinocilia heights. Tip link tensions show parallel behavior in peripheral columns of the bundle and serial behavior in central columns when the tip link modulus is near or above that of collagen (1x10(9) N/m(2)). This analysis shows that lumped parameter models of single stereocilia columns can show some aspects of bundle mechanics; however, a distributed, 3-D model is needed to explore overall bundle behavior.

  17. How to Perform Permanent His Bundle Pacing: Tips and Tricks.

    PubMed

    Vijayaraman, Pugazhendhi; Dandamudi, Gopi

    2016-12-01

    Right ventricular pacing can cause ventricular dyssynchrony and result in reduced left ventricular systolic function and heart failure. Permanent His bundle pacing is a more physiologic form of pacing, but can be technically challenging. In this article, we describe our technique for permanent His bundle pacing including special considerations and limitations associated with His bundle pacing. © 2016 Wiley Periodicals, Inc.

  18. 76 FR 61365 - Bundled Payments for Care Improvement Initiative

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-04

    ... 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 Improvement.../patient-care-models/bundled-payments-for-care-improvement.html . Application Submission Deadline:...

  19. Turkish and Native English Academic Writers' Use of Lexical Bundles

    ERIC Educational Resources Information Center

    Öztürk, Yusuf; Köse, Gül Durmusoglu

    2016-01-01

    Lexical bundles such as "on the other hand" and "as a result of" are extremely common and important in academic discourse. The appropriate use of lexical bundles typical of a specific academic discipline is important for writers and the absence of such bundles may not sound fluent and native-like. Recent studies (e.g. Adel…

  20. 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

  1. Effect of Calcium Phosphate–Hybridized Tendon Graft in Anatomic Single-Bundle ACL Reconstruction in Goats

    PubMed Central

    Mutsuzaki, Hirotaka; Fujie, Hiromichi; Nakajima, Hiromi; Fukagawa, Makoto; Nomura, Shunsuke; Sakane, Masataka

    2016-01-01

    Background: We previously developed a novel technique using an alternate soaking process that improves tendon-bone healing by hybridizing the tendon graft with calcium phosphate (CaP). However, the effects of the CaP-hybridized tendon graft on anatomic single-bundle anterior cruciate ligament (ACL) reconstruction remain unclear. Purpose: To determine the effects of CaP-hybridized tendon grafts compared with untreated tendon grafts 6 months after anatomic single-bundle ACL reconstruction using a goat model. Study Design: Controlled laboratory study. Methods: Animals were divided into a CaP group (n = 5 goats) and a control group (n = 5 goats), and we analyzed (1) knee kinematics and in situ forces under applied anterior tibial loads of 50 N and internal tibial torque of 2.0 N·m in the grafts at full extension and at 60° and 90° of knee flexion, (2) the mean percentage of bone tunnel enlargement using computed tomography (CT), and (3) the histology of the tendon-bone interface. Results: The in situ forces under applied anterior tibial loads of 50 N at 60° and 90° of knee flexion in the CaP group were greater than those in the control group (P < .05). The red safranin-O–stained area, indicating glycosaminoglycans in the cartilage layers at the joint aperture sites of the anterior femoral and posterior tibial bone tunnel, was greater in the CaP group than that in the control group (P < .05). The lengths of the nonbonding gap area between the anterior femoral and posterior tibial bone tunnels in the control group were greater than those in the CaP group (P < .05). No significant difference could be detected in the mean percentage of bone tunnel enlargement between the 2 groups. Conclusion: The CaP-hybridized tendon graft enhanced tendon-bone healing at the joint aperture site in both anterior femoral and posterior tibial tunnels 6 months after anatomic single-bundle ACL reconstruction in goats. The in situ forces under applied anterior tibial loads at greater

  2. 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.

  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.

  4. Irreducible vector bundles on some elliptic non-Kahler threefolds

    NASA Astrophysics Data System (ADS)

    Brînzănescu, Vasile; Vuletescu, Victor

    2015-05-01

    We study rank-2 vector bundles on non-Kähler threefolds π : X → B, which are elliptic principal bundles with at least one non-zero Chern class over a complex surface B with no curves. In this case, we prove that every rank-2 irreducible vector bundle on X is a pull-back from B up to a twist by a line bundle. These 2-vector bundles are, via the Kobayashi-Hitchin correspondence, solutions of the Yang-Mills equations on the threefold X.

  5. Elastocapillary bundling of high aspect-ratio metallic glass nanowires

    NASA Astrophysics Data System (ADS)

    Hu, Zhonglue; Uzun, Ceren; Dong, Ziye; Li, Wei; Bernussi, Ayrton A.; Kumar, Golden

    2017-07-01

    Collapsing and bundling of wet nanostructures can be a desirable or an unwanted phenomenon depending on the target application. We study the effect of the aspect-ratio and solvent surface tension on bundling of Pt-based metallic glass nanowires prepared by thermoplastic molding. The results show that the bundling can be quantitatively described by the competition between the Laplacian capillary force and the elastic restoring force. Supercritical CO2 drying can prevent bundling to form vertically aligned metallic glass nanowires with high aspect-ratios (>15). Optical measurements and simulations reveal that the diffuse reflectance of metallic glass nanowires strongly depends on their profile (vertical or bundled).

  6. Anterior cruciate ligament (ACL) injury

    MedlinePlus

    Cruciate ligament injury - anterior; ACL injury; Knee injury - anterior cruciate ligament (ACL) ... knee. It prevents the knee from bending out. Anterior cruciate ligament (ACL) is in the middle of the knee. ...

  7. Anterior Cruciate Ligament (ACL) Injuries

    MedlinePlus

    ... Week of Healthy Breakfasts Shyness Anterior Cruciate Ligament (ACL) Injuries KidsHealth > For Teens > Anterior Cruciate Ligament (ACL) ... and Recovery Coping With an ACL Injury About ACL Injuries A torn anterior cruciate ligament (ACL) is ...

  8. Care bundles reduce readmissions for COPD.

    PubMed

    Matthews, Healther; Tooley, Cathy; Nicholls, Carol; Lindsey-Halls, Anna

    In 2011, the respiratory nursing team at the James Paget University Hospital Foundation Trust were considering introducing a discharge care bundle for patients admitted with an acute exacerbation of chronic obstructive pulmonary disease. At the same time, the trust was asking for applications for Commissioning for Quality and Innovation schemes (CQUINs). These are locally agreed packages of quality improvement goals and indicators, which, if achieved in total, enable the provider to earn its full CQUIN payment. A CQUIN scheme should address the three domains of quality, safety and effectiveness, patient experience and also show innovation. This article discusses how the care bundle was introduced and how, over a 12-month period, it showed tangible results in improving the care pathway for COPD patients as well as reducing readmissions and saving a significant amount of money.

  9. 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.

  10. 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.

  11. Type IIB flux compactifications on twistor bundles

    NASA Astrophysics Data System (ADS)

    Imaanpur, Ali

    2014-02-01

    We construct a U(1) bundle over N(1,1), usually considered as an SO(3) bundle on CP2, and show that type IIB supergravity can be consistently compactified over it. With the five form flux turned on, there is a solution for which the metric becomes Einstein. We further turn on 3-form fluxes and show that there is a one parameter family of solutions. In particular, there is a limiting solution of large 3-form fluxes for which two U(1) fiber directions of the metric shrink to zero size. We also discuss compactifications over N(1,1) to AdS3. All solutions turn out to be non-supersymmetric.

  12. Non-abelian higher gauge theory and categorical bundle

    NASA Astrophysics Data System (ADS)

    Viennot, David

    2016-12-01

    A gauge theory is associated with a principal bundle endowed with a connection permitting to define horizontal lifts of paths. The horizontal lifts of surfaces cannot be defined into a principal bundle structure. An higher gauge theory is an attempt to generalize the bundle structure in order to describe horizontal lifts of surfaces. A such attempt is particularly difficult for the non-abelian case. Some structures have been proposed to realize this goal (twisted bundle, gerbes with connection, bundle gerbe, 2-bundle). Each of them uses a category in place of the total space manifold of the usual principal bundle structure. Some of them replace also the structure group by a category (more precisely a Lie crossed module viewed as a category). But the base space remains still a simple manifold (possibly viewed as a trivial category with only identity arrows). We propose a new principal categorical bundle structure, with a Lie crossed module as structure groupoid, but with a base space belonging to a bigger class of categories (which includes non-trivial categories), that we called affine 2-spaces. We study the geometric structure of the categorical bundles built on these categories (which are a more complicated structure than the 2-bundles) and the connective structures on these bundles. Finally we treat an example interesting for quantum dynamics which is associated with the Bloch wave operator theory.

  13. Uncovering ecosystem service bundles through social preferences.

    PubMed

    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.

  14. Alpha1 LASSO data bundles Lamont, OK

    SciTech Connect

    Gustafson, William Jr; Vogelmann, Andrew; Endo, Satoshi; Toto, Tami; Xiao, Heng; Li, Zhijin; Cheng, Xiaoping; Krishna, Bhargavi

    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.

  15. 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

  16. [Anterior tarsal tunnel syndrome].

    PubMed

    Miliam, Palle B; Basse, Peter N

    2009-03-30

    Anterior tarsal tunnel syndrome is a rare entrapment neuropathy of the deep peroneal nerve beneath the extensor retinaculum of the ankle. It may be rare because it is underrecognized clinically.We present a case regarding a 29-year-old man, drummer, who for one and a half year experienced clinical symptoms of anterior tarsal tunnel syndrome. A surgical decompression of the anterior tarsal tunnel was performed, and at the check three months later the symptoms where gone. One year after, there were still no symptoms.

  17. [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.

  18. Diagnostic accuracy of exercise thallium-201 single-photon emission computed tomography in patients with left bundle branch block.

    PubMed

    Larcos, G; Gibbons, R J; Brown, M L

    1991-09-15

    Recent reports have proposed that abnormal apical or anterior wall perfusion with exercise thallium-201 imaging may increase diagnostic accuracy for disease of the left anterior descending artery in patients with left bundle branch block (LBBB). To evaluate these suggestions, 83 patients with LBBB who underwent thallium-201 single-photon emission computed tomography and coronary angiography within an interval of 3 months were retrospectively reviewed. There were 59 men and 24 women aged 33 to 84 years (mean 65). Myocardial perfusion to the apex, anterior wall and anterior septum were scored qualitatively by consensus of 2 experienced observers and by quantitative analysis in comparison with a normal data base. The sensitivity, specificity and accuracy of perfusion defects in these segments were then expressed according to angiographic findings. Significant stenosis of vessels within the left anterior descending artery territory was present in 38 patients. By receiver-operator characteristic analysis, a fixed or reversible defect within the apex by the qualitative method was the best criterion for coronary artery disease. However, although highly sensitive (79 and 85% by the qualitative and quantitative methods, respectively), an apical defect was neither specific (38 and 16%, respectively), nor accurate (57 and 46%, respectively). Perfusion abnormalities in the anterior wall and septum were also of limited diagnostic accuracy. Thus, modified interpretative criteria in patients with LBBB are not clinically useful in the assessment of left anterior descending artery disease.

  19. Diagnostic accuracy of exercise thallium-201 single-photon emission computed tomography in patients with left bundle branch block

    SciTech Connect

    Larcos, G.; Gibbons, R.J.; Brown, M.L. )

    1991-09-15

    Recent reports have proposed that abnormal apical or anterior wall perfusion with exercise thallium-201 imaging may increase diagnostic accuracy for disease of the left anterior descending artery in patients with left bundle branch block (LBBB). To evaluate these suggestions, 83 patients with LBBB who underwent thallium-201 single-photon emission computed tomography and coronary angiography within an interval of 3 months were retrospectively reviewed. There were 59 men and 24 women aged 33 to 84 years (mean 65). Myocardial perfusion to the apex, anterior wall and anterior septum were scored qualitatively by consensus of 2 experienced observers and by quantitative analysis in comparison with a normal data base. The sensitivity, specificity and accuracy of perfusion defects in these segments were then expressed according to angiographic findings. Significant stenosis of vessels within the left anterior descending artery territory was present in 38 patients. By receiver-operator characteristic analysis, a fixed or reversible defect within the apex by the qualitative method was the best criterion for coronary artery disease. However, although highly sensitive (79 and 85% by the qualitative and quantitative methods, respectively), an apical defect was neither specific (38 and 16%, respectively), nor accurate (57 and 46%, respectively). Perfusion abnormalities in the anterior wall and septum were also of limited diagnostic accuracy. Thus, modified interpretative criteria in patients with LBBB are not clinically useful in the assessment of left anterior descending artery disease.

  20. Development of Strengthened Bundle High Temperature Superconductors

    SciTech Connect

    Lue, J.W.; Lubell, M.S.; Demko, J.A.; Tomsic, M.; Sinha, U.

    1997-12-31

    In the process of developing high temperature superconducting (HTS) transmission cables, it was found that mechanical strength of the superconducting tape is the most crucial property that needs to be improved. It is also desirable to increase the current carrying capacity of the conductor so that fewer layers are needed to make the kilo-amp class cables required for electric utility usage. A process has been developed by encapsulating a stack of Bi-2223/Ag tapes with a silver or non-silver sheath to form a strengthened bundle superconductor. This process was applied to HTS tapes made by the Continuous Tube Forming and Filling (CTFF) technique pursued by Plastronic Inc. and HTS tapes obtained from other manufacturers. Conductors with a bundle of 2 to 6 HTS tapes have been made. The bundled conductor is greatly strengthened by the non-silver sheath. No superconductor degradation as compared to the sum of the original critical currents of the individual tapes was seen on the finished conductors.

  1. 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

  2. Modelling packing interactions in parallel helix bundles: pentameric bundles of nicotinic receptor M2 helices.

    PubMed

    Sankararamakrishnan, R; Sansom, M S

    1995-11-01

    The transbilayer pore of the nicotinic acetylcholine receptor (nAChR) is formed by a pentameric bundle of M2 helices. Models of pentameric bundles of M2 helices have been generated using simulated annealing via restrained molecular dynamics. The influence of: (a) the initial C alpha template; and (b) screening of sidechain electrostatic interactions on the geometry of the resultant M2 helix bundles is explored. Parallel M2 helices, in the absence of sidechain electrostatic interactions, pack in accordance with simple ridges-in-grooves considerations. This results in a helix crossing angle of ca. +12 degrees, corresponding to a left-handed coiled coil structure for the bundle as a whole. Tilting of M2 helices away from the central pore axis at their C-termini and/or inclusion of sidechain electrostatic interactions may perturb such ridges-in-grooves packing. In the most extreme cases right-handed coiled coils are formed. An interplay between inter-helix H-bonding and helix bundle geometry is revealed. The effects of changes in electrostatic screening on the dimensions of the pore mouth are described and the significance of these changes in the context of models for the nAChR pore domain is discussed.

  3. 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.

  4. The diverse effects of mechanical loading on active hair bundles

    PubMed Central

    Ó Maoiléidigh, Dáibhid; Nicola, Ernesto M.; Hudspeth, A. J.

    2012-01-01

    Hair cells in the auditory, vestibular, and lateral-line systems of vertebrates receive inputs through a remarkable variety of accessory structures that impose complex mechanical loads on the mechanoreceptive hair bundles. Although the physiological and morphological properties of the hair bundles in each organ are specialized for detecting the relevant inputs, we propose that the mechanical load on the bundles also adjusts their responsiveness to external signals. We use a parsimonious description of active hair-bundle motility to show how the mechanical environment can regulate a bundle’s innate behavior and response to input. We find that an unloaded hair bundle can behave very differently from one subjected to a mechanical load. Depending on how it is loaded, a hair bundle can function as a switch, active oscillator, quiescent resonator, or low-pass filter. Moreover, a bundle displays a sharply tuned, nonlinear, and sensitive response for some loading conditions and an untuned or weakly tuned, linear, and insensitive response under other circumstances. Our simple characterization of active hair-bundle motility explains qualitatively most of the observed features of bundle motion from different organs and organisms. The predictions stemming from this description provide insight into the operation of hair bundles in a variety of contexts. PMID:22308449

  5. Prenatal muscle fiber development and bundle structure in beef and dairy cattle.

    PubMed

    Albrecht, E; Lembcke, C; Wegner, J; Maak, S

    2013-08-01

    were developed. The size of primary bundles nearly doubled from 6 mo of gestation to birth in all breeds. In summary, differences among breeds in the early fetal muscle fiber development were detected in contractile differentiation and partly in muscle fiber bundle structure. A prolonged secondary fiber generation and altered contractile differentiation may be involved in breed differences of postnatal muscle development.

  6. 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. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  7. Effects of knee flexion angle and loading conditions on the end-to-end distance of the posterior cruciate ligament: a comparison of the roles of the anterolateral and posteromedial bundles.

    PubMed

    Wang, Joon Ho; Kato, Yuki; Ingham, Sheila J M; Maeyama, Akira; Linde-Rosen, Monica; Smolinski, Patrick; Fu, Freddie H; Harner, Christopher

    2014-12-01

    It is commonly accepted that the anterolateral (AL) bundle of the posterior cruciate ligament (PCL) is tight in flexion and that the posteromedial (PM) bundle is tight in extension. However, a recent in vivo study showed that both bundles were tight in extension. To investigate the effects of knee flexion angle, rotational torque, and anterior/posterior translational force on the end-to-end distance between the femoral and tibial insertion sites of each bundle of the PCL. Descriptive laboratory study. Cadaveric knees (10 specimens) were mounted on a robotic system, and the relative positional data between the femur and tibia were acquired during passive flexion/extension, with an applied 5-N·m rotational torque and an applied 89-N translational force. The bony surface and PCL insertion data were acquired with a 3-dimensional scanner after gross dissection and were superimposed onto the positional data. The end-to-end distance between the 2 PCL insertion sites of the femur and tibia was measured. The end-to-end distance increased from full extension to 90° for both the AL (9.2 ± 1.8 mm; from 30.0 to 39.2 mm) and PM bundles (5.8 ± 2.2 mm; from 32.0 to 37.7 mm). With an internal rotational torque, the end-to-end distance of the PM bundle increased significantly (P < .05) at 0°, 30°, and 60° of knee flexion. Under a posterior translational force at 90° of knee flexion, the length of both bundles increased to their longest measurements (AM bundle: 40.6 ± 4.2 mm; PM bundle: 38.4 ± 3.8 mm). The end-to-end distance of the AL and PM bundles of the PCL increased in flexion, and this pattern was maintained during tests with posterior translational force. The PM bundle was more affected by the rotational torque than was the AL bundle. Both bundles of the PCL may serve a greater functional role in flexion than in extension. The PM bundle might be more important for the control of rotation than the AL bundle. Posterior translation at 90° of knee flexion could be the

  8. 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.

  9. Symptomatic Type IV Dual Left Anterior Descending Coronary Artery

    PubMed Central

    Papadopoulos, Kyriacos; Georgiou, Georgios M.; Nicolaides, Evagoras

    2016-01-01

    Dual left anterior descending coronary artery is a rare congenital anomaly with 4 subtypes. Double left anterior descending coronary artery originating from the left main stem and the right coronary artery (type IV dual left anterior descending artery) has been reported to occur in 0.01% to 0.7% of patients undergoing cardiac catheterization. We report a case of a 49-year-old woman who was found to have this anomaly during coronary angiography. The patient had been complaining of chest pain that mimics angina pectoris and exercise tolerance test was positive for myocardial ischemia. PMID:28203572

  10. The avalanche process of the fiber bundle model with defect

    NASA Astrophysics Data System (ADS)

    Hao, Da-Peng; Tang, Gang; Xia, Hui; Xun, Zhi-Peng; Han, Kui

    2017-04-01

    In order to explore the impacts of defect on the tensile fracture process of materials, the fiber bundle model with defect is constructed based on the classical fiber bundle model. In the fiber bundle model with defect, the two key parameters are the mean size and the density of defects. In both uniform and Weibull threshold distributions, the mean size and density all bring impacts on the threshold distribution of fibers. By means of analytical approximation and numerical simulation, we show that the two key parameters of the model have substantial effects on the failure process of the bundle. From macroscopic view, the defect described by the altering of threshold distribution of fibers will has a significant impact on the mechanical properties of the bundle. While in microscopic scale, the statistical properties of the model are still harmonious with the classical fiber bundle model.

  11. Expansion and Polarity Sorting in Microtubule-Dynein Bundles

    NASA Astrophysics Data System (ADS)

    Zemel, A.; Mogilner, A.

    Interactions of multiple molecular motors with dynamicpolymers, such as actin and microtubules, form the basis for many processes in the cell cytoskeleton. One example is the active `sorting' of microtubule bundles by dynein molecular motors into aster-like arrays of microtubules; in these bundles dynein motors cross-link and slide neighboring microtubules apart. A number of models have been suggested to quantify the active dynamics of cross-linked bundles of polar filaments. In the case of densely packed bundles, however, a major complication arises from the fact that each microtubule interacts with multiple neighboring filaments. To explicitly take these interactions into account we performed detailed computer simulations in which the equations of motion for all microtubules in the bundle were iteratively solved. Our simulations demonstrate the phenomenon of polarity sorting and reveal the variable-rate of the concurrent bundle expansion and its dependence on the nature of the microtubule-motor interactions.

  12. Cooperativity and Frustration in Protein-Mediated Parallel Actin Bundles

    NASA Astrophysics Data System (ADS)

    Shin, Homin; Drew, Kirstin R. Purdy; Bartles, James R.; Wong, Gerard C. L.; Grason, Gregory M.

    2009-12-01

    We examine the mechanism of bundling of cytoskeletal actin filaments by two representative bundling proteins, fascin and espin. Small-angle x-ray studies show that increased binding from linkers drives a systematic overtwist of actin filaments from their native state, which occurs in a linker-dependent fashion. Fascin bundles actin into a continuous spectrum of intermediate twist states, while espin only allows for untwisted actin filaments and fully overtwisted bundles. Based on a coarse-grained, statistical model of protein binding, we show that the interplay between binding geometry and the intrinsic flexibility of linkers mediates cooperative binding in the bundle. We attribute the respective continuous (discontinuous) bundling mechanisms of fascin (espin) to difference in the stiffness of linker bonds themselves.

  13. A Tannakian approach to dimensional reduction of principal bundles

    NASA Astrophysics Data System (ADS)

    Álvarez-Cónsul, Luis; Biswas, Indranil; García-Prada, Oscar

    2017-08-01

    Let P be a parabolic subgroup of a connected simply connected complex semisimple Lie group G. Given a compact Kähler manifold X, the dimensional reduction of G-equivariant holomorphic vector bundles over X × G / P was carried out in Álvarez-Cónsul and García-Prada (2003). This raises the question of dimensional reduction of holomorphic principal bundles over X × G / P. The method of Álvarez-Cónsul and García-Prada (2003) is special to vector bundles; it does not generalize to principal bundles. In this paper, we adapt to equivariant principal bundles the Tannakian approach of Nori, to describe the dimensional reduction of G-equivariant principal bundles over X × G / P, and to establish a Hitchin-Kobayashi type correspondence. In order to be able to apply the Tannakian theory, we need to assume that X is a complex projective manifold.

  14. Monopoles and Modifications of Bundles over Elliptic Curves

    NASA Astrophysics Data System (ADS)

    Levin, Andrey M.; Olshanetsky, Mikhail A.; Zotov, Andrei V.

    2009-06-01

    Modifications of bundles over complex curves is an operation that allows one to construct a new bundle from a given one. Modifications can change a topological type of bundle. We describe the topological type in terms of the characteristic classes of the bundle. Being applied to the Higgs bundles modifications establish an equivalence between different classical integrable systems. Following Kapustin and Witten we define the modifications in terms of monopole solutions of the Bogomolny equation. We find the Dirac monopole solution in the case R × (elliptic curve). This solution is a three-dimensional generalization of the Kronecker series. We give two representations for this solution and derive a functional equation for it generalizing the Kronecker results. We use it to define Abelian modifications for bundles of arbitrary rank. We also describe non-Abelian modifications in terms of theta-functions with characteristic.

  15. 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

  16. Morphology selection via geometric frustration in chiral filament bundles.

    PubMed

    Hall, Douglas M; Bruss, Isaac R; Barone, Justin R; Grason, Gregory M

    2016-07-01

    In assemblies, the geometric frustration of a locally preferred packing motif leads to anomalous behaviours, from self-limiting growth to defects in the ground state. Here, we demonstrate that geometric frustration selects the equilibrium morphology of cohesive bundles of chiral filaments, an assembly motif critical to a broad range of biological and synthetic nanomaterials. Frustration of inter-filament spacing leads to optimal shapes of self-twisting bundles that break the symmetries of packing and of the underlying inter-filament forces, paralleling a morphological instability in spherical two-dimensional crystals. Equilibrium bundle morphology is controlled by a parameter that characterizes the relative costs of filament bending and the straining of cohesive bonds between filaments. This parameter delineates the boundaries between stable, isotropic cylindrical bundles and anisotropic, twisted-tape bundles. We also show how the mechanical and interaction properties of constituent amyloid fibrils may be extracted from the mesoscale dimensions of the anisotropic bundles that they form.

  17. 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

  18. Knee laxity control in revision anterior cruciate ligament reconstruction versus anterior cruciate ligament reconstruction and lateral tenodesis: clinical assessment using computer-assisted navigation.

    PubMed

    Colombet, Philippe

    2011-06-01

    Rotational laxity control is one of the different options to improve functional results after anterior cruciate ligament reconstruction. Lateral extra-articular tenodesis has been proposed to reduce the rotational laxity, especially in challenging situations such as revision reconstruction after biological failure. We currently lack the practical clinical tools to objectively assess knee rotational laxities. Addition of a lateral tenodesis to anatomic single-bundle anterior cruciate ligament reconstruction with hamstring tendon graft could improve the knee laxity control, particularly the internal rotation, compared with a standard single-bundle anterior cruciate ligament reconstruction. Controlled laboratory study. Twenty patients underwent navigated anatomic anteromedial bundle revision anterior cruciate ligament reconstruction with addition of percutaneous extra-articular tenodesis using the same hamstring tendon graft. The navigation was used to optimize femoral and tibial tunnel positions and to measure the knee kinematics in response to the anterior drawer test, Lachman test, maximum internal/external rotation test, and pivot-shift test. All patients underwent revision after failure without any technical error found or new trauma. Two sequential reconstruction protocols were used to assess the contribution of the extra-articular tenodesis and single anteromedial bundle anterior cruciate ligament reconstruction to restrain tibial translations and coupled axial rotation occurring with the manually performed clinical laxity tests. In group A, the intra-articular reconstruction was fixed first and then the lateral tenodesis was fixed, and in group B, the protocol was reversed. Measurements were performed before the reconstruction, after the first part was fixed, and after the second part was fixed in each protocol. At 90° of flexion, addition of lateral tenodesis had a significant effect on coupled internal rotation (P = .003). Addition of the intra

  19. Higher order mechanics on graded bundles

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    In this paper we develop a geometric approach to higher order mechanics on graded bundles in both, the Lagrangian and Hamiltonian formalism, via the recently discovered weighted algebroids. We present the corresponding Tulczyjew triple for this higher order situation and derive in this framework the phase equations from an arbitrary (also singular) Lagrangian or Hamiltonian, as well as the Euler-Lagrange equations. As important examples, we geometrically derive the classical higher order Euler-Lagrange equations and analogous reduced equations for invariant higher order Lagrangians on Lie groupoids.

  20. 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.

  1. Local load-sharing fiber bundle model in higher dimensions

    NASA Astrophysics Data System (ADS)

    Sinha, Santanu; Kjellstadli, Jonas T.; Hansen, Alex

    2015-08-01

    We consider the local load-sharing fiber bundle model in one to five dimensions. Depending on the breaking threshold distribution of the fibers, there is a transition where the fracture process becomes localized. In the localized phase, the model behaves as the invasion percolation model. The difference between the local load-sharing fiber bundle model and the equal load-sharing fiber bundle model vanishes with increasing dimensionality with the characteristics of a power law.

  2. Heat Transfer Analysis in Wire Bundles for Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Rickman, S. L.; Iamello, C. J.

    2016-01-01

    Design of wiring for aerospace vehicles relies on an understanding of "ampacity" which refers to the current carrying capacity of wires, either, individually or in wire bundles. Designers rely on standards to derate allowable current flow to prevent exceedance of wire temperature limits due to resistive heat dissipation within the wires or wire bundles. These standards often add considerable margin and are based on empirical data. Commercial providers are taking an aggressive approach to wire sizing which challenges the conventional wisdom of the established standards. Thermal modelling of wire bundles may offer significant mass reduction in a system if the technique can be generalized to produce reliable temperature predictions for arbitrary bundle configurations. Thermal analysis has been applied to the problem of wire bundles wherein any or all of the wires within the bundle may carry current. Wire bundles present analytical challenges because the heat transfer path from conductors internal to the bundle is tortuous, relying on internal radiation and thermal interface conductance to move the heat from within the bundle to the external jacket where it can be carried away by convective and radiative heat transfer. The problem is further complicated by the dependence of wire electrical resistivity on temperature. Reduced heat transfer out of the bundle leads to higher conductor temperatures and, hence, increased resistive heat dissipation. Development of a generalized wire bundle thermal model is presented and compared with test data. The steady state heat balance for a single wire is derived and extended to the bundle configuration. The generalized model includes the effects of temperature varying resistance, internal radiation and thermal interface conductance, external radiation and temperature varying convective relief from the free surface. The sensitivity of the response to uncertainties in key model parameters is explored using Monte Carlo analysis.

  3. Isomonodromic Deformations and Very Stable Vector Bundles of Rank Two

    NASA Astrophysics Data System (ADS)

    Biswas, Indranil; Heu, Viktoria; Hurtubise, Jacques

    2017-08-01

    For the universal isomonodromic deformation of an irreducible logarithmic rank two connection over a smooth complex projective curve of genus at least two, consider the family of holomorphic vector bundles over curves underlying this universal deformation. In a previous work we proved that the vector bundle corresponding to a general parameter of this family is stable. Here we prove that the vector bundle corresponding to a general parameter is in fact very stable, meaning it does not admit any nonzero nilpotent Higgs field.

  4. Complete bundle moduli reduction in heterotic string compactifications

    NASA Astrophysics Data System (ADS)

    Curio, Gottfried

    2012-05-01

    A major problem in discussing heterotic string models is the stabilisation of the many vector bundle moduli via the superpotential generated by world-sheet instantons. In arXiv:1110.6315 we have discussed the method to make a discrete twist in a large and much discussed class of vector bundles such that the generation number gets new contributions (which can be tuned suitably) and at the same time the space of bundle moduli of the new, twisted bundle is a proper subspace (where the 'new', non-generic twist class exists) of the original bundle moduli space; one thus gets a model, closely related to the original model one started with, but with enhanced flexibility in the generation number and where on the other hand the number of bundle moduli is somewhat reduced. Whereas in the previous paper the emphasis was on examples for the new flexibility in the generation number we here classify and describe explicitly the twists and give the precise reduction formula (for the number of moduli) for SU(5) bundles leading to an SU(5) GUT group in four dimensions. Finally we give various examples where the bundle moduli space is reduced completely: the superpotential for such rigid bundles becomes a function of the complex structure moduli alone (besides the exponential Kahler moduli contribution).

  5. 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.

  6. Isothermal microcalorimetry, a tool for probing SWNT bundles.

    PubMed

    Marquis, Renaud; Greco, Carla; Schultz, Patrick; Meunier, Stéphane; Mioskowski, Charles

    2009-11-01

    The bundling state of several dry single-walled carbon nanotube (SWNT) samples is compared using isothermal microcalorimetry (IMC). So as to get different dry samples with various bundling states, the pristine SWNTs were pretreated with a solution of an aromatic amphiphile with or without sonication, washed and dried before being studied by IMC. The bundling state of the different SWNT samples, which was first analyzed by TEM, was then correlated to the obtained IMC data thanks to the interpretation of the observed energy transfer phenomena. From our results, IMC appears to be an interesting technique for the surface probing of dry SWNT samples, and herein for the evaluation of the bundling state.

  7. Economic Analyses in Anterior Cruciate Ligament Reconstruction: A Qualitative and Systematic Review.

    PubMed

    Saltzman, Bryan M; Cvetanovich, Gregory L; Nwachukwu, Benedict U; Mall, Nathan A; Bush-Joseph, Charles A; Bach, Bernard R

    2016-05-01

    As the health care system in the United States (US) transitions toward value-based care, there is an increased emphasis on understanding the cost drivers and high-value procedures within orthopaedics. To date, there has been no systematic review of the economic literature on anterior cruciate ligament reconstruction (ACLR). To evaluate the overall evidence base for economic studies published on ACLR in the orthopaedic literature. Data available on the economics of ACLR are summarized and cost drivers associated with the procedure are identified. Systematic review. All economic studies (including US-based and non-US-based) published between inception of the MEDLINE database and October 3, 2014, were identified. Given the heterogeneity of the existing evidence base, a qualitative, descriptive approach was used to assess the collective results from the economic studies on ACLR. When applicable, comparisons were made for the following cost-related variables associated with the procedure for economic implications: outpatient versus inpatient surgery (or outpatient vs overnight hospital stay vs >1-night stay); bone-patellar tendon-bone (BPTB) graft versus hamstring (HS) graft source; autograft versus allograft source; staged unilateral ACLR versus bilateral ACLR in a single setting; single- versus double-bundle technique; ACLR versus nonoperative treatment; and other unique comparisons reported in single studies, including computer-assisted navigation surgery (CANS) versus traditional surgery, early versus delayed ACLR, single- versus double-incision technique, and finally the costs of ACLR without comparison of variables. A total of 24 studies were identified and included; of these, 17 included studies were cost identification studies. The remaining 7 studies were cost utility analyses that used economic models to investigate the effect of variables such as the cost of allograft tissue, fixation devices, and physical therapy, the percentage and timing of revision

  8. Oscillatory characteristics of carbon nanotubes inside carbon nanotube bundles

    NASA Astrophysics Data System (ADS)

    Ansari, R.; Alipour, A.; Sadeghi, F.

    2012-12-01

    This article presents a comprehensive study on the mechanics of carbon nanotubes (CNTs) oscillating in CNT bundles. Using the continuum approximation along with Lennard-Jones (LJ) potential function, new semi-analytical expressions in terms of double integrals are presented to evaluate van der Waals (vdW) potential energy and interaction force upon which the equation of motion is directly solved. The obtained potential expression enables one to arrive at a new semi-analytical formula for the exact evaluation of oscillation frequency. Also, an algebraic frequency formula is extracted on the basis of the simplifying assumption of constant vdW force. Based on the present expressions, a thorough study on various aspects of operating frequencies under different system parameters is given, which permits fresh insight into the problem. The strong dependence of oscillation frequency on system parameters, such as the extrusion distance and initial velocity of the core as initial conditions for the motion is indicated. Interestingly, a specific initial velocity is found at which the oscillation frequency is independent of the core length. In addition, a relation between this specific initial velocity and the escape velocity is disclosed.

  9. Bundled tungsten oxide nanowires under thermal processing

    NASA Astrophysics Data System (ADS)

    Sun, Shibin; Zhao, Yimin; Xia, Yongde; Zou, Zengda; Min, Guanghui; Zhu, Yanqiu

    2008-07-01

    Ultra-thin W18O49 nanowires were initially obtained by a simple solvothermal method using tungsten chloride and cyclohexanol as precursors. Thermal processing of the resulting bundled nanowires has been carried out in air in a tube furnace. The morphology and phase transformation behavior of the as-synthesized nanowires as a function of annealing temperature have been characterized by x-ray diffraction and electron microscopy. The nanostructured bundles underwent a series of morphological evolution with increased annealing temperature, becoming straighter, larger in diameter, and smaller in aspect ratio, eventually becoming irregular particles with size up to 5 µm. At 500 °C, the monoclinic W18O49 was completely transformed to monoclinic WO3 phase, which remains stable at high processing temperature. After thermal processing at 400 °C and 450 °C, the specific surface areas of the resulting nanowires dropped to 110 m2 g-1 and 66 m2 g-1 respectively, compared with that of 151 m2 g-1 for the as-prepared sample. This study may shed light on the understanding of the geometrical and structural evolution occurring in nanowires whose working environment may involve severe temperature variations.

  10. 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.

  11. Confinement-Dependent Friction in Peptide Bundles

    PubMed Central

    Erbaş, Aykut; Netz, Roland R.

    2013-01-01

    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

  12. 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.

  13. Bundled capillary electrophoresis using microstructured fibres.

    PubMed

    Rogers, Benjamin; Gibson, Graham T T; Oleschuk, Richard D

    2011-01-01

    Joule heating, arising from the electric current passing through the capillary, causes many undesired effects in CE that ultimately result in band broadening. The use of narrow-bore capillaries helps to solve this problem as smaller cross-sectional area results in decreased Joule heating and the rate of heat dissipation is increased by the larger surface-to-volume ratio. Issues arising from such small capillaries, such as poor detection sensitivity, low loading capacity and high flow-induced backpressure (complicating capillary loading) can be avoided by using a bundle of small capillaries operating simultaneously that share buffer reservoirs. Microstructured fibres, originally designed as waveguides in the telecommunication industry, are essentially a bundle of parallel ∼5 μm id channels that extend the length of a fibre having otherwise similar dimensions to conventional CE capillaries. This work presents the use of microstructured fibres for CZE, taking advantage of their relatively high surface-to-volume ratio and the small individual size of each channel to effect highly efficient separations, particularly for dye-labelled peptides.

  14. Histological analysis of the tibial anterior cruciate ligament insertion.

    PubMed

    Oka, Shinya; Schuhmacher, Peter; Brehmer, Axel; Traut, Ulrike; Kirsch, Joachim; Siebold, Rainer

    2016-03-01

    This study was performed to investigate the morphology of the tibial anterior cruciate ligament (ACL) by histological assessment. The native (undissected) tibial ACL insertion of six fresh-frozen cadaveric knees was cut into four sagittal sections parallel to the long axis of the medial tibial spine. For histological evaluation, the slices were stained with haematoxylin and eosin, Safranin O and Russell-Movat pentachrome. All slices were digitalized and analysed at a magnification of 20×. The anterior tibial ACL insertion was bordered by a bony anterior ridge. The most medial ACL fibres inserted from the medial tibial spine and were adjacent to the articular cartilage of the medial tibial plateau. Parts of the bony insertions of the anterior and posterior horns of the lateral meniscus were in close contact with the lateral part of the tibial ACL insertion. A small fat pad was located just posterior to the functional ACL fibres. The anterior-posterior length of the medial ACL insertion was an average of 10.8 ± 1.1 mm compared with the lateral, which was only 6.2 ± 1.1 mm (p < 0.001). There were no central or posterolateral inserting ACL fibres. The shape of the bony tibial ACL insertion was 'duck-foot-like'. In contrast to previous findings, the functional mid-substance fibres arose from the most posterior part of the 'duck-foot' in a flat and 'c-shaped' way. The most anterior part of the tibial ACL insertion was bordered by a bony anterior ridge and the most medial by the medial tibial spine. No posterolateral fibres nor ACL bundles have been found histologically. This histological investigation may improve our understanding of the tibial ACL insertion and may provide important information for anatomical ACL reconstruction.

  15. The mischievous bundle: a case of varying degrees of right bundle branch block on alternate beats during exercise stress testing.

    PubMed

    Singh, Sukhvinder

    2013-05-01

    A 78-year-old male was referred for exercise stress testing. He developed incomplete right bundle branch block during first stage of exercise and later on developed incomplete and complete right bundle branch block on alternate beats (2:1). During first minute of recovery he developed complete right bundle branch block on all beats (1:1). At 3 minutes of recovery, baseline electrocardiographic pattern was resumed. Variable degree of right bundle branch block on alternate beats is a rare phenomenon. The plausible mechanisms responsible for this phenomenon are being discussed. ©2012, Wiley Periodicals, Inc.

  16. Coherent hollow-core waveguide bundles for thermal imaging.

    PubMed

    Gal, Udi; Harrington, James; Ben-David, Moshe; Bledt, Carlos; Syzonenko, Nicholas; Gannot, Israel

    2010-09-01

    There has been very little work done in the past to extend the wavelength range of fiber image bundles to the IR range. This is due, in part, to the lack of IR transmissive fibers with optical and mechanical properties analogous to the oxide glass fibers currently employed in the visible fiber bundles. Our research is aimed at developing high-resolution hollow-core coherent IR fiber bundles for transendoscopic infrared imaging. We employ the hollow glass waveguide (HGW) technology that was used successfully to make single-HGWs with Ag/AgI thin film coatings to form coherent bundles for IR imaging. We examine the possibility of developing endoscopic systems to capture thermal images using hollow waveguide fiber bundles adjusted to the 8-10?mum spectral range and investigate the applicability of such systems. We carried out a series of measurements in order to characterize the optical properties of the fiber bundles. These included the attenuation, resolution, and temperature response. We developed theoretical models and simulation tools that calculate the light propagation through HGW bundles, and which can be used to calculate the optical properties of the fiber bundles. Finally, the HGW fiber bundles were used to transmit thermal images of various heated objects; the results were compared with simulation results. The experimental results are encouraging, show an improvement in the resolution and thermal response of the HGW fiber bundles, and are consistent with the theoretical results. Nonetheless, additional improvements in the attenuation of the bundles are required in order to be able to use this technology for medical applications.

  17. Metallic Conductive Nanowires Elaborated by PVD Metal Deposition on Suspended DNA Bundles.

    PubMed

    Brun, Christophe; Elchinger, Pierre-Henri; Nonglaton, Guillaume; Tidiane-Diagne, Cheikh; Tiron, Raluca; Thuaire, Aurélie; Gasparutto, Didier; Baillin, Xavier

    2017-09-01

    Metallic conductive nanowires (NWs) with DNA bundle core are achieved, thanks to an original process relying on double-stranded DNA alignment and physical vapor deposition (PVD) metallization steps involving a silicon substrate. First, bundles of DNA are suspended with a repeatable process between 2 µm high parallel electrodes with separating gaps ranging from 800 nm to 2 µm. The process consists in the drop deposition of a DNA lambda-phage solution on the electrodes followed by a naturally evaporation step. The deposition process is controlled by the DNA concentration within the buffer solution, the drop volume, and the electrode hydrophobicity. The suspended bundles are finally metallized with various thicknesses of titanium and gold by a PVD e-beam evaporation process. The achieved NWs have a width ranging from a few nanometers up to 100 nm. The electrical behavior of the achieved 60 and 80 nm width metallic NWs is shown to be Ohmic and their intrinsic resistance is estimated according to different geometrical models of the NW section area. For the 80 nm width NWs, a resistance of about few ohms is established, opening exploration fields for applications in microelectronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    PubMed

    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.

  19. 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

  20. Surgical management of partial tears of the anterior cruciate ligament.

    PubMed

    Papalia, Rocco; Franceschi, Francesco; Zampogna, Biagio; Tecame, Andrea; Maffulli, Nicola; Denaro, Vincenzo

    2014-01-01

    Partial anterior cruciate ligament (ACL) tears involving the posterolateral (PL) bundle can lead to rotatory laxity of the knee, while tears involving the anteromedial (AM) bundle result in abnormal anteroposterior laxity of the knee. In this systematic review, we examine the best evidence on the management of partial tears of the ACL. A comprehensive search of several databases was performed from the inception of the database to December 2011, using various combinations of keywords focusing on clinical outcomes of human patients who had partial tears of ACL and who had undergone ACL augmentation. We evaluated the methodological quality of each article using the Coleman Methodology Score. Ten articles published in peer-reviewed journals were identified (392 males and 242 females), with a mean modified Coleman methodology of 66.1 ± 10.2. Only two studies compared standard ACL reconstruction and augmentation techniques. No study has a sample large enough to allow establishing guidelines. Validated and standardized proprioception assessment methods should be used to report outcomes. Imaging outcomes should be compared to functional outcomes, and a control group consisting of traditional complete ACL reconstruction should be present. There is a need to perform appropriately powered randomized controlled trials presenting clinical outcome with homogeneous score systems to allow accurate statistical analysis. ACL augmentation technique, preserving the intact AM or PL bundle of the ACL, is encouraging but currently available evidences are too weak to support his routine use in clinical practice.

  1. Presenting Lexical Bundles for Explicit Noticing with Schematic Linguistic Representation

    ERIC Educational Resources Information Center

    Thomson, Haidee Elizabeth

    2016-01-01

    Lexical bundles are essential for fluency, but their incompleteness is a stumbling block for learners. In this study, two presentation methods to increase awareness of lexical bundles through explicit noticing are explored and compared with incidental exposure. The three conditions in this study were as follows: noticing with schematic linguistic…

  2. Lexical Bundles in University Spoken and Written Registers

    ERIC Educational Resources Information Center

    Biber, Douglas; Barbieri, Federica

    2007-01-01

    Lexical bundles--recurrent sequences of words--are important building blocks of discourse in spoken and written registers. Previous research has shown that lexical bundles are especially prevalent in university classroom teaching, where they serve three major discourse functions: stance expressions, discourse organizers, and referential…

  3. Vibration of Tube Bundles in Cross Water Flow

    NASA Astrophysics Data System (ADS)

    Dikarev, I. M.; Loshkareva, E. A.; Kartuesova, A. Yu.

    2017-03-01

    Results of vibration testing of an experimental tube bundle of 72 tubes of diameter 0.012 m in the case of cooling-water flow across the tubes with different versions of installation of baffles are described. The influence of the displacement of the baffles on the parameters of vibration of the tube bundle is determined.

  4. 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.

  5. 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…

  6. 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.

  7. Lexical Bundles in University Spoken and Written Registers

    ERIC Educational Resources Information Center

    Biber, Douglas; Barbieri, Federica

    2007-01-01

    Lexical bundles--recurrent sequences of words--are important building blocks of discourse in spoken and written registers. Previous research has shown that lexical bundles are especially prevalent in university classroom teaching, where they serve three major discourse functions: stance expressions, discourse organizers, and referential…

  8. As Can Be Seen: Lexical Bundles and Disciplinary Variation

    ERIC Educational Resources Information Center

    Hyland, Ken

    2008-01-01

    An important component of fluent linguistic production is control of the multi-word expressions referred to as clusters, chunks or bundles. These are extended collocations which appear more frequently than expected by chance, helping to shape meanings in specific contexts and contributing to our sense of coherence in a text. Bundles have begun to…

  9. Lexical Bundles in L1 and L2 Academic Writing

    ERIC Educational Resources Information Center

    Chen, Yu-Hua; Baker, Paul

    2010-01-01

    This paper adopts an automated frequency-driven approach to identify frequently-used word combinations (i.e., "lexical bundles") in academic writing. Lexical bundles retrieved from one corpus of published academic texts and two corpora of student academic writing (one L1, the other L2), were investigated both quantitatively and qualitatively.…

  10. Interprofessional Perspectives on ABCDE Bundle Implementation: A Focus Group Study.

    PubMed

    Boehm, Leanne M; Vasilevskis, Eduard E; Mion, Lorraine C

    The ABCDE bundle is a multifaceted, interprofessional intervention that is associated with reduced ventilator and delirium days as well as increased likelihood of mobility in intensive care. The aim of this study is to describe organizational domains that contribute to variation in ABCDE bundle implementation as reported by intensive care unit providers and to examine the capability of a conceptual framework for identifying variation in ABCDE bundle implementation. We conducted 2 separate focus groups that included nurses, respiratory therapists, occupational and physical therapists (N = 16) from the surgical and medical intensive care units at 1 academic medical center. All participants had experience performing ABCDE bundle activities. Variation in how the ABCDE bundle was interpreted and executed within and across disciplines was noted. Organizational facets, the physical environment, labor quantity and quality, task burden, provider attitudes, and patient characteristics were noted to influence ABCDE bundle execution. The difficulty coordinating and implementing early mobility was emphasized. The number of disciplines required to perform an activity and individual component complexity was reported to influence ABCDE bundle implementation. Nurses repeatedly described challenges with coordinating care across disciplines. Small tests of change, adequate staffing, interprofessional training and protocol development efforts, and role modeling may be effective methods for successful ABCDE bundle implementation.

  11. Method of pressure pulse cleaning a tube bundle heat exchanger

    SciTech Connect

    Scharton, T.D.; Taylor, G.B.

    1987-04-07

    A method is described of removing the products of corrosion, oxidation, sedimentation and comparable chemical reactions collectively known as sludge which settle on the bottom of a tube bundle heat exchange and form a pile of sludge. The tube bundle heat exchanger is characterized by a tube bundle heat exchanger wall and a thick metal plate known as a tube sheet near the lower portion of the tube bundle heat exchanger wall's interior surface. The tube sheet serves to support the lower ends of a multiplicity of heat exchanger tubes within the tube bundle heat exchanger. The tube bundle heat exchange wall further comprises a multiplicity of small holes known as hand holes, manways, drain lines and vents, located around its circumference and above the tube sheet. The method is described of removing the pile of sludge which settles on the tube sheet comprising: a. locating at least one air-gun type pressure pulse shock wave source outside the tube bundle heat exchanger so as to be able to introduce pressure pulse shock waves through one or more of the multiplicity of hand holes, manways, drain lines and vents; and b. filling the tube bundle heat exchanger with a liquid to a level above the pile of sludge.

  12. Computational imaging through a fiber-optic bundle

    NASA Astrophysics Data System (ADS)

    Lodhi, Muhammad A.; Dumas, John Paul; Pierce, Mark C.; Bajwa, Waheed U.

    2017-05-01

    Compressive sensing (CS) has proven to be a viable method for reconstructing high-resolution signals using low-resolution measurements. Integrating CS principles into an optical system allows for higher-resolution imaging using lower-resolution sensor arrays. In contrast to prior works on CS-based imaging, our focus in this paper is on imaging through fiber-optic bundles, in which manufacturing constraints limit individual fiber spacing to around 2 μm. This limitation essentially renders fiber-optic bundles as low-resolution sensors with relatively few resolvable points per unit area. These fiber bundles are often used in minimally invasive medical instruments for viewing tissue at macro and microscopic levels. While the compact nature and flexibility of fiber bundles allow for excellent tissue access in-vivo, imaging through fiber bundles does not provide the fine details of tissue features that is demanded in some medical situations. Our hypothesis is that adapting existing CS principles to fiber bundle-based optical systems will overcome the resolution limitation inherent in fiber-bundle imaging. In a previous paper we examined the practical challenges involved in implementing a highly parallel version of the single-pixel camera while focusing on synthetic objects. This paper extends the same architecture for fiber-bundle imaging under incoherent illumination and addresses some practical issues associated with imaging physical objects. Additionally, we model the optical non-idealities in the system to get lower modelling errors.

  13. 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.

  14. Active Amplification by Spontaneous Hair Bundle Oscillations

    NASA Astrophysics Data System (ADS)

    Jülicher, Frank

    2003-05-01

    In a quiet environment, the ears of many vertebrates emit so-called spontaneous oto-acoustic emissions as manifestations of active processes in the inner ear. It has been suggested that the ear employs dynamical systems which are self-tuned to the critical point of an oscillating instability or Hopf bifurcation. It has recently been demonstrated that hair bundles, which are the mechanosensitive elements of sensory hair cells in the bull frog's sacculum, have the ability to generate noisy oscillations. In the presence of noise, the Hopf bifurcation of an oscillator is concealed by the noise, however the principal signatures remain, such as frequency selectivity and nonlinear response. Using the observed autocorrelation function and the linear response function, the activity of the noisy oscillator can be characterized by its violation of the fluctuation-dissipation theorem.

  15. 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.

  16. Bundled automobile insurance coverage and accidents.

    PubMed

    Li, Chu-Shiu; Liu, Chwen-Chi; Peng, Sheng-Chang

    2013-01-01

    This paper investigates the characteristics of automobile accidents by taking into account two types of automobile insurance coverage: comprehensive vehicle physical damage insurance and voluntary third-party liability insurance. By using a unique data set in the Taiwanese automobile insurance market, we explore the bundled automobile insurance coverage and the occurrence of claims. It is shown that vehicle physical damage insurance is the major automobile coverage and affects the decision to purchase voluntary liability insurance coverage as a complement. Moreover, policyholders with high vehicle physical damage insurance coverage have a significantly higher probability of filing vehicle damage claims, and if they additionally purchase low voluntary liability insurance coverage, their accident claims probability is higher than those who purchase high voluntary liability insurance coverage. Our empirical results reveal that additional automobile insurance coverage information can capture more driver characteristics and driving behaviors to provide useful information for insurers' underwriting policies and to help analyze the occurrence of automobile accidents.

  17. Cyclic hardening in bundled actin networks.

    PubMed

    Schmoller, K M; Fernández, P; Arevalo, R C; Blair, D L; Bausch, A R

    2010-01-01

    Nonlinear deformations can irreversibly alter the mechanical properties of materials. Most soft materials, such as rubber and living tissues, display pronounced softening when cyclically deformed. Here we show that, in contrast, reconstituted networks of crosslinked, bundled actin filaments harden when subject to cyclical shear. As a consequence, they exhibit a mechano-memory where a significant stress barrier is generated at the maximum of the cyclic shear strain. This unique response is crucially determined by the network architecture: at lower crosslinker concentrations networks do not harden, but soften showing the classic Mullins effect known from rubber-like materials. By simultaneously performing macrorheology and confocal microscopy, we show that cyclic shearing results in structural reorganization of the network constituents such that the maximum applied strain is encoded into the network architecture.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. Localized Statistics for DW-MRI Fiber Bundle Segmentation.

    PubMed

    Lankton, Shawn; Melonakos, John; Malcolm, James; Dambreville, Samuel; Tannenbaum, Allen

    2008-01-01

    We describe a method for segmenting neural fiber bundles in diffusion-weighted magnetic resonance images (DWMRI). As these bundles traverse the brain to connect regions, their local orientation of diffusion changes drastically, hence a constant global model is inaccurate. We propose a method to compute localized statistics on orientation information and use it to drive a variational active contour segmentation that accurately models the non-homogeneous orientation information present along the bundle. Initialized from a single fiber path, the proposed method proceeds to capture the entire bundle. We demonstrate results using the technique to segment the cingulum bundle and describe several extensions making the technique applicable to a wide range of tissues.

  5. 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

  6. Big things come in bundled packages: implications of bundled payment systems in health care reimbursement reform.

    PubMed

    Delisle, Dennis R

    2013-01-01

    With passage of the Affordable Care Act, the ever-evolving landscape of health care braces for another shift in the reimbursement paradigm. As health care costs continue to rise, providers are pressed to deliver efficient, high-quality care at flat to minimally increasing rates. Inherent systemwide inefficiencies between payers and providers at various clinical settings pose a daunting task for enhancing collaboration and care coordination. A change from Medicare's fee-for-service reimbursement model to bundled payments offers one avenue for resolution. Pilots using such payment models have realized varying degrees of success, leading to the development and upcoming implementation of a bundled payment initiative led by the Center for Medicare and Medicaid Innovation. Delivery integration is critical to ensure high-quality care at affordable costs across the system. Providers and payers able to adapt to the newly proposed models of payment will benefit from achieving cost reductions and improved patient outcomes and realize a competitive advantage.

  7. Anterior cruciate ligament repair - slideshow

    MedlinePlus

    ... this page: //medlineplus.gov/ency/presentations/100230.htm Anterior cruciate ligament repair - Series—Normal anatomy To use the sharing ... to slide 5 out of 5 Overview The anterior cruciate ligament (ACL) is a ligament in the center of ...

  8. Editorial Commentary: Renaissance of Primary Anterior Cruciate Ligament Repair: Is History Repeating Itself?

    PubMed

    Hohmann, Erik

    2016-12-01

    In a comparative Level III study, Achtnich et al. compared suture anchor repair of acute proximal anterior cruciate ligament avulsion tears with single-bundle anterior cruciate ligament reconstruction with the quadrupled semitendinosus tendon. Short-term follow-up at a mean of 28 months showed that the between-group differences were not different. These results are encouraging but not different from other published series 25+ years ago. Only time will tell whether the long-term outcomes are identical and whether these techniques will also die a slow death. Hopefully history is not repeating itself.

  9. Asynchrony of the early maturation of white matter bundles in healthy infants: quantitative landmarks revealed noninvasively by diffusion tensor imaging.

    PubMed

    Dubois, Jessica; Dehaene-Lambertz, Ghislaine; Perrin, Muriel; Mangin, Jean-François; Cointepas, Yann; Duchesnay, Edouard; Le Bihan, Denis; Hertz-Pannier, Lucie

    2008-01-01

    Normal cognitive development in infants follows a well-known temporal sequence, which is assumed to be correlated with the structural maturation of underlying functional networks. Postmortem studies and, more recently, structural MR imaging studies have described qualitatively the heterogeneous spatiotemporal progression of white matter myelination. However, in vivo quantification of the maturation phases of fiber bundles is still lacking. We used noninvasive diffusion tensor MR imaging and tractography in twenty-three 1-4-month-old healthy infants to quantify the early maturation of the main cerebral fascicles. A specific maturation model, based on the respective roles of different maturational processes on the diffusion phenomena, was designed to highlight asynchronous maturation across bundles by evaluating the time-course of mean diffusivity and anisotropy changes over the considered developmental period. Using an original approach, a progression of maturation in four relative stages was determined in each tract by estimating the maturation state and speed, from the diffusion indices over the infants group compared with an adults group on one hand, and in each tract compared with the average over bundles on the other hand. Results were coherent with, and extended previous findings in 8 of 11 bundles, showing the anterior limb of the internal capsule and cingulum as the most immature, followed by the optic radiations, arcuate and inferior longitudinal fascicles, then the spinothalamic tract and fornix, and finally the corticospinal tract as the most mature bundle. Thus, this approach provides new quantitative landmarks for further noninvasive research on brain-behavior relationships during normal and abnormal development.

  10. 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.

  11. 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.

  12. Short term results of anterior cruciate ligament augmentation in professional and amateur athletes.

    PubMed

    Yazdi, Hamidreza; Torkaman, Ali; Ghahramani, Morteza; Moradi, Amin; Nazarian, Ara; Ghorbanhoseini, Mohammad

    2017-06-01

    Anterior cruciate ligament (ACL) reconstruction is a widely accepted procedure; however, controversies exist about ACL augmentation. The purpose of this study was to assess the clinical outcomes of ACL augmentation in professional and amateur athletes with isolated single bundle ACL tears. A consecutive series of professional and amateur athletes with partial ACL tears who underwent selective bundle reconstruction were analyzed. Stability was assessed with the Lachman test, anterior-drawer test, pivot-shift test and KT-1000 arthrometer. Functional assessment was performed using the subjective Lysholm questionnaire. Fifty-six patients were enrolled. The mean follow-up period was 19.3 months. All patients had posterolateral bundle (PLB) tears, and no anteromedial bundle (AMB) tears were found. The Lysholm score improved significantly from 78 (SD = 2.69) preoperatively to 96 (SD = 3.41) postoperatively (P value <0.0001). The pivot-shift test, Lachman test and anterior-drawer test results were negative in all cases postoperatively. Anterior tibial translation from neutral was 4.9 mm (SD = 2.7) preoperatively, and decreased significantly to 2.1 (SD = 0.6) postoperatively, measured with a KT-1000 arthrometer (P value <0.00001). In this study, we showed that ACL augmentation had good results in symptomatic professional and amateur athletes, and although further studies are needed to investigate long-term results, we recommend this surgery for all symptomatic athletic patients, especially those who would like to maintain an active lifestyle. Level of evidence IV.

  13. 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

  14. Anterior tarsal tunnel syndrome.

    PubMed

    DiDomenico, Lawrence A; Masternick, Eric B

    2006-07-01

    Compression of the deep peroneal nerve is commonly referred to as anterior tarsal tunnel syndrome. Although rare, this syndrome remains poorly diagnosed. The syndrome is characterized by pain, weakness, and sensory changes of the foot and ankle. Non-operative measures should be attempted to reduce or remove the external compression along the anterior aspect of the foot and ankle. Other options include shoe modifications, cortisone injections,and physical therapy. If conservative management fails to relieve the symptoms, surgical decompression of the entrapped nerve can be performed. The deep peroneal nerve is released from compressive forces in the entrapment site. This can be performed at the more proximal level at the extensor retinaculum or more distally at the level of the tarsal metatarsal site.

  15. [Anterior pseudodiverticulum after laryngectomy].

    PubMed

    Pitzer, G; Oursin, C; Wolfensberger, M

    1998-01-01

    An anterior neopharyngeal pseudodiverticulum is a mucosal pouch located between the tongue and hypopharynx due to an epiglottis-like posterior tissue band that forms after total laryngectomy. This condition has rarely been mentioned in literature. Incidence, symptoms, treatment, and possible etiologic factors were examined. Twenty post-laryngectomy patients were questioned about swallowing disorders and were examined clinically and by barium swallow. Eleven patients were found to have a pseudodiverticulum, of which 9 patients suffered from dysphagia. We found no correlation between the formation of a pseudodiverticulum and radiotherapy or post-laryngectomy complications. All symptomatic patients were treated by dissecting the posterior tissue band endoscopically with a CO2-laser, bringing complete relief of symptoms in 8 of 9 patients. Our study showed that the anterior pseudodiverticulum can be a frequent cause of dysphagia after laryngectomy. It can easily be diagnosed clinically and radiologically. Endoscopic treatment with a CO2-laser is simple and effective.

  16. Cost-Effectiveness of a Central Venous Catheter Care Bundle

    PubMed Central

    Halton, Kate A.; Cook, David; Paterson, David L.; Safdar, Nasia; Graves, Nicholas

    2010-01-01

    Background A bundled approach to central venous catheter care is currently being promoted as an effective way of preventing catheter-related bloodstream infection (CR-BSI). Consumables used in the bundled approach are relatively inexpensive which may lead to the conclusion that the bundle is cost-effective. However, this fails to consider the nontrivial costs of the monitoring and education activities required to implement the bundle, or that alternative strategies are available to prevent CR-BSI. We evaluated the cost-effectiveness of a bundle to prevent CR-BSI in Australian intensive care patients. Methods and Findings A Markov decision model was used to evaluate the cost-effectiveness of the bundle relative to remaining with current practice (a non-bundled approach to catheter care and uncoated catheters), or use of antimicrobial catheters. We assumed the bundle reduced relative risk of CR-BSI to 0.34. Given uncertainty about the cost of the bundle, threshold analyses were used to determine the maximum cost at which the bundle remained cost-effective relative to the other approaches to infection control. Sensitivity analyses explored how this threshold alters under different assumptions about the economic value placed on bed-days and health benefits gained by preventing infection. If clinicians are prepared to use antimicrobial catheters, the bundle is cost-effective if national 18-month implementation costs are below $1.1 million. If antimicrobial catheters are not an option the bundle must cost less than $4.3 million. If decision makers are only interested in obtaining cash-savings for the unit, and place no economic value on either the bed-days or the health benefits gained through preventing infection, these cost thresholds are reduced by two-thirds. Conclusions A catheter care bundle has the potential to be cost-effective in the Australian intensive care setting. Rather than anticipating cash-savings from this intervention, decision makers must be prepared

  17. Compartment pressure monitoring during anterior cruciate ligament reconstruction.

    PubMed

    Amendola, A; Faber, K; Willits, K; Miniaci, A; Labib, S; Fowler, P

    1999-09-01

    A prospective double blind randomized study was carried out using 20 healthy males with anterior cruciate ligament (ACL) insufficiency undergoing bone-patellar tendon-bone ACL reconstruction. The subjects were randomized into either water or saline irrigation and then underwent identical reconstructive procedures using an arthroscopic pump. Continuous preoperative, intraoperative, and postoperative pressures were monitored using the slit catheter technique. Blood pressure and compartment pressure measurements were continuously recorded and noted at all stages of the procedure. Mean preoperative anterior and posterior compartment pressures were similar in both groups. No significant differences were noted between the anterior and posterior compartments of each group. No difference between water and saline irrigation was identified throughout the procedure. In both groups, postoperative pressures were slightly lower in the anterior and posterior compartments compared with preoperative pressures, but not significantly.

  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. Alignment of inducible vascular progenitor cells on a micro-bundle scaffold improves cardiac repair following myocardial infarction.

    PubMed

    Jamaiyar, Anurag; Wan, Weiguo; Ohanyan, Vahagn; Enrick, Molly; Janota, Danielle; Cumpston, Devan; Song, Hokyung; Stevanov, Kelly; Kolz, Christopher L; Hakobyan, Tatev; Dong, Feng; Newby, Bi-Min Zhang; Chilian, William M; Yin, Liya

    2017-07-01

    Ischemic heart disease is still the leading cause of death even with the advancement of pharmaceutical therapies and surgical procedures. Early vascularization in the ischemic heart is critical for a better outcome. Although stem cell therapy has great potential for cardiovascular regeneration, the ideal cell type and delivery method of cells have not been resolved. We tested a new approach of stem cell therapy by delivery of induced vascular progenitor cells (iVPCs) grown on polymer micro-bundle scaffolds in a rat model of myocardial infarction. iVPCs partially reprogrammed from vascular endothelial cells (ECs) had potent angiogenic potential and were able to simultaneously differentiate into vascular smooth muscle cells (SMCs) and ECs in 2D culture. Under hypoxic conditions, iVPCs also secreted angiogenic cytokines such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) as measured by enzyme-linked immunosorbent assay (ELISA). A longitudinal micro-scaffold made from poly(lactic-co-glycolic acid) was sufficient for the growth and delivery of iVPCs. Co-cultured ECs and SMCs aligned well on the micro-bundle scaffold similarly as in the vessels. 3D cell/polymer micro-bundles formed by iVPCs and micro-scaffolds were transplanted into the ischemic myocardium in a rat model of myocardial infarction (MI) with ligation of the left anterior descending artery. Our in vivo data showed that iVPCs on the micro-bundle scaffold had higher survival, and better retention and engraftment in the myocardium than free iVPCs. iVPCs on the micro-bundles promoted better cardiomyocyte survival than free iVPCs. Moreover, iVPCs and iVPC/polymer micro-bundles treatment improved cardiac function (ejection fraction and fractional shortening, endocardial systolic volume) measured by echocardiography, increased vessel density, and decreased infarction size [endocardial and epicardial infarct (scar) length] better than untreated controls at 8 weeks after MI

  20. Is Remnant Preservation Truly Beneficial to Anterior Cruciate Ligament Reconstruction Healing? Clinical and Magnetic Resonance Imaging Evaluations of Remnant-Preserved Reconstruction.

    PubMed

    Naraoka, Takuya; Kimura, Yuka; Tsuda, Eiichi; Yamamoto, Yuji; Ishibashi, Yasuyuki

    2017-04-01

    Remnant-preserved anterior cruciate ligament (ACL) reconstruction was introduced to improve clinical outcomes and biological healing. However, the effects of remnant preservation and the influence of the delay from injury until reconstruction on the outcomes of this technique are still uncertain. Purpose/Hypothesis: The purposes of this study were to evaluate whether remnant preservation improved the clinical outcomes and graft incorporation of ACL reconstruction and to examine the influence of the delay between ACL injury and reconstruction on the usefulness of remnant preservation. We hypothesized that remnant preservation improves clinical results and accelerates graft incorporation and that its effect is dependent on the delay between ACL injury and reconstruction. Cohort study; Level of evidence, 2. A total of 151 consecutive patients who underwent double-bundle ACL reconstruction using a semitendinosus graft were enrolled in this study: 74 knees underwent ACL reconstruction without a remnant (or the remnant was <25% of the intra-articular portion of the graft; NR group), while 77 knees underwent ACL reconstruction with remnant preservation (RP group). These were divided into 4 subgroups based on the time from injury to surgery: phase 1 was <3 weeks (n = 24), phase 2 was 3 to less than 8 weeks (n = 70), phase 3 was 8 to 20 weeks (n = 32), and phase 4 was >20 weeks (n = 25). Clinical measurements, including KT-1000 arthrometer side-to-side anterior tibial translation measurements, were assessed at 3, 6, 12, and 24 months after reconstruction. Magnetic resonance imaging evaluations of graft maturation and graft-tunnel integration of the anteromedial and posterolateral bundles were assessed at 3, 6, and 12 months after reconstruction. There was no difference in side-to-side anterior tibial translation between the NR and RP groups. There was also no difference in graft maturation between the 2 groups. Furthermore, the time from ACL injury until reconstruction did

  1. Onset of recent exertional dyspnoea in a firefighter with left bundle-branch block

    PubMed Central

    De Rosa, Roberto; Ratti, Gennaro; Lamberti, Monica

    2014-01-01

    Background The presence of a left bundle-branch block (LBBB) among firefighters raises questions about stratifying risk of subsequent cardiovascular events as this conduction disorder may mask underlying coronary artery disease. This report describes the case of a firefighter with a history LBBB with exertional dyspnoea of recent onset after work activity. Case report A 39-year-old male firefighter with LBBB developed exertional dyspnoea after a prolonged session of work. ECG and treadmill test only showed a permanent LBBB; echocardiography and myocardial scintigraphy did not add to this. However, multislice CT (MSCT) showed a significant stenosis in the mid-left anterior descending artery (LAD). Coronary angiography confirmed the stenosis with subsequent placement of a coronary stent. Conclusions An occupational physician should take into account that factors such as age and low cardiovascular risk do not always exclude heart disease, especially when there are conduction system abnormalities that can mask possible coronary artery disease. PMID:25352387

  2. "Bundling" HIV prevention: integrating services to promote synergistic gain.

    PubMed

    Ickovics, Jeannette R

    2008-03-01

    Bundling is defined as the aggregation of services to increase effectiveness (i.e., creating synergy of effort). The purpose of this commentary is to review the utilization and potential benefits of bundling in its application to HIV prevention. Review of the literature to provide a broad perspective on the concept of bundling and specific examples of bundling in HIV prevention. Benefits, challenges and directions are considered. To be effective, bundling must offer strategic advantage: greater value, less cost. It provides an opportunity to target multiple risk behaviors simultaneously for synergistic gain. Technological advances including rapid HIV tests permit noninvasive sampling in clinical and non-clinical settings. Bundling of HIV prevention provides an opportunity to reach high-risk persons who are asymptomatic and/or may not otherwise seek care by eliminating barriers to prevention. We must implement programs that work and consider innovative approaches to stem the AIDS epidemic; bundling provides one such opportunity to create an efficient paradigm targeting multiple risk behaviors simultaneously.

  3. 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

  4. The neurofibrovascular bundle of the inferior oblique muscle as its ancillary origin.

    PubMed Central

    Stager, D R

    1996-01-01

    PURPOSE: To establish that the neurofibrovascular bundle (NFVB) of the inferior oblique muscle (IO) has ligamentous qualities that enable it to function as an ancillary origin to the muscle. Also, to show that the NFVB does function as the ancillary origin for the IO muscle, particularly when recessing and anteriorly transposing its insertion. METHODS: Fresh (no formaldehyde preservative) cadaver and patient eyes were studied anatomically, histologically, and physiologically. Eighteen orbits were dissected to isolate the IO, the inferior rectus (IR), and the NFVB to demonstrate the linear course of the NFVB and its adjacent fibrous bands. The shape of the muscle was documented. Coronal sections of the two whole, intact orbits were analyzed histologically. Light and electron microscopic sections of an autopsy specimen and a surgical specimen were used to evaluate the capsule of the NFVB and the adjacent fibrous bands near the anterior portion of the NFVB and their attachment to the IR and IO muscle capsules. The elastic modulus was measured in six in situ and six in vitro cadaver NFVB specimens and in six in vivo surgical cases at the time of denervation of the NFVB. For additional comparison, four in vitro cadaver superior oblique tendons were similarly tested. Six eyes that developed recurrent IO overaction following an anterior transposition procedure were surgically explored to determine what structure was serving as its ancillary origin. RESULTS: Gross anatomic and microscopic studies showed a linear orientation of the NFVB with adjacent fibrous bands anteriorly joining the IO and IR muscle capsules. The surgical specimens of the anterior portion of the NFVB show about 50% nerve and 50% fibrocollagenous capsule with the collagen fibers aligned parallel to the NFVB. The elastic modulus was highest (stiffest) in surgical specimens of the NFVB and in situ cadaver NFVB, followed by in vitro cadaver NFVB and, finally, in vitro cadaver superior oblique tendon. In

  5. Two-state approach to stochastic hair bundle dynamics

    NASA Astrophysics Data System (ADS)

    Clausznitzer, Diana; Lindner, Benjamin; Jülicher, Frank; Martin, Pascal

    2008-04-01

    Hair cells perform the mechanoelectrical transduction of sound signals in the auditory and vestibular systems of vertebrates. The part of the hair cell essential for this transduction is the so-called hair bundle. In vitro experiments on hair cells from the sacculus of the American bullfrog have shown that the hair bundle comprises active elements capable of producing periodic deflections like a relaxation oscillator. Recently, a continuous nonlinear stochastic model of the hair bundle motion [Nadrowski , Proc. Natl. Acad. Sci. U.S.A. 101, 12195 (2004)] has been shown to reproduce the experimental data in stochastic simulations faithfully. Here, we demonstrate that a binary filtering of the hair bundle's deflection (experimental data and continuous hair bundle model) does not change significantly the spectral statistics of the spontaneous as well as the periodically driven hair bundle motion. We map the continuous hair bundle model to the FitzHugh-Nagumo model of neural excitability and discuss the bifurcations between different regimes of the system in terms of the latter model. Linearizing the nullclines and assuming perfect time-scale separation between the variables we can map the FitzHugh-Nagumo system to a simple two-state model in which each of the states corresponds to the two possible values of the binary-filtered hair bundle trajectory. For the two-state model, analytical expressions for the power spectrum and the susceptibility can be calculated [Lindner and Schimansky-Geier, Phys. Rev. E 61, 6103 (2000)] and show the same features as seen in the experimental data as well as in simulations of the continuous hair bundle model.

  6. Systematic evaluation of bundled SPC water for biomolecular simulations.

    PubMed

    Gopal, Srinivasa M; Kuhn, Alexander B; Schäfer, Lars V

    2015-04-07

    In bundled SPC water models, the relative motion of groups of four water molecules is restrained by distance-dependent potentials. Bundled SPC models have been used in hybrid all-atom/coarse-grained (AA/CG) multiscale simulations, since they enable to couple atomistic SPC water with supra-molecular CG water models that effectively represent more than a single water molecule. In the present work, we systematically validated and critically tested bundled SPC water models as solvent for biomolecular simulations. To that aim, we investigated both thermodynamic and structural properties of various biomolecular systems through molecular dynamics (MD) simulations. Potentials of mean force of dimerization of pairs of amino acid side chains as well as hydration free energies of single side chains obtained with bundled SPC and standard (unrestrained) SPC water agree closely with each other and with experimental data. Decomposition of the hydration free energies into enthalpic and entropic contributions reveals that in bundled SPC, this favorable agreement of the free energies is due to a larger degree of error compensation between hydration enthalpy and entropy. The Ramachandran maps of Ala3, Ala5, and Ala7 peptides are similar in bundled and unrestrained SPC, whereas for the (GS)2 peptide, bundled water leads to a slight overpopulation of extended conformations. Analysis of the end-to-end distance autocorrelation times of the Ala5 and (GS)2 peptides shows that sampling in more viscous bundled SPC water is about two times slower. Pronounced differences between the water models were found for the structure of a coiled-coil dimer, which is instable in bundled SPC but not in standard SPC. In addition, the hydration of the active site of the serine protease α-chymotrypsin depends on the water model. Bundled SPC leads to an increased hydration of the active site region, more hydrogen bonds between water and catalytic triad residues, and a significantly slower exchange of water

  7. Dark-field illuminated reflectance fiber bundle endoscopic microscope

    NASA Astrophysics Data System (ADS)

    Liu, Xuan; Huang, Yong; Kang, Jin U.

    2011-04-01

    We propose a reflectance fiber bundle microscope using a dark-field illumination configuration for applications in endoscopic medical imaging and diagnostics. Our experiment results show that dark-field illumination can effectively suppress strong specular reflection from the proximal end of the fiber bundle. We realized a lateral resolution of 4.4 μm using the dark-field illuminated fiber bundle configuration. To demonstrate the feasibility of using the system to study cell morphology, we obtained still and video images of two thyroid cancer cell lines. Our results clearly allow differentiation of different cancer cell types.

  8. Critical switching impulse breakdown of long bundle-conductor gaps

    SciTech Connect

    Rizk, F.A.M.

    1996-01-01

    The paper presents a generalized physical approach to account for the effect of bundle geometry on critical switching impulse strength of long air gaps. The model covers phase-to-ground as well as phase-to-phase insulation. It has been applied to conventional symmetrical bundles as well as to more complex open configurations. The effect of bundle conductors was investigated for the following basic configurations: conductor-plane, conductor-rod, conductor-tower leg, conductor-tower window as well as phase-to-phase, within a wide range of clearances. The model is compared with previous analytical approaches as well as to extensive experimental results.

  9. Bundle duct interaction studies for fuel assemblies. [LMFBR

    SciTech Connect

    Hsia, H.T.S.; Kaplan, S.

    1981-06-01

    It is known that the wire-wrapped rods and duct in an LMFBR are undergoing a gradual structural distortion from the initially uniform geometry under the combined effects of thermal expansion and irradiation induced swelling and creep. These deformations have a significant effect on flow characteristics, thus causing changes in thermal behavior such as cladding temperature and temperature distribution within a bundle. The temperature distribution may further enhance or retard irradiation induced deformation of the bundle. This report summarizes the results of the continuing effort in investigating the bundle-duct interaction, focusing on the need for the large development plant.

  10. Characterization of a space orbited incoherent fiber optic bundle

    NASA Technical Reports Server (NTRS)

    Dewalt, Stephen A.; Taylor, Edward W.

    1993-01-01

    The results of a study performed to determine the effects of adverse space environments on a bundle of over 1800 optical fibers orbited for 69 months are reported. Experimental results are presented on an incoherent fiber optic bundle oriented in low Earth orbit aboard the Long Duration Exposure Facility (LDEF) satellite as part of the Space Environment Effects Experiment (M0006). Measurements were performed to determine if space induced radiation effects changed the fiber bundle characteristics. Data demonstrating the success of light transmitting fibers to withstand the adverse space environment are presented.

  11. Structural Transitions of F-Actin:Espin Bundles

    NASA Astrophysics Data System (ADS)

    Purdy, Kirstin; Bartles, James; Wong, Gerard

    2006-03-01

    Espin is an actin bundling protein involved in the formation of the parallel bundles of filamentous actin in hair cell stereocilia. Mutations in espin are implicated in deafness phenotypes in mice and humans. We present measurements of the F-actin structures induced by wild type and by mutated espin obtained via small angle x-ray scattering and fluorescence microscopy. We found that wild type espin induced a paracrystalline hexagonal array of twisted F-actin, whereas the mutated espin only condensed the F-actin into a nematic-like phase. The possibility of coexisting nematic and bundled actin in mixtures containing both mutant and wild type espins was also investigated.

  12. Repair of Chronic Tibialis Anterior Tendon Rupture With a Major Defect Using Gracilis Allograft.

    PubMed

    Burton, Alex; Aydogan, Umur

    2016-08-01

    Tibialis anterior tendon (TAT) rupture is an uncommon injury, however, it can cause substantial deficit. Diagnosis is often delayed due to lack of initial symptoms; yet loss of function over time typically causes the patient to present for treatment. This delay usually ends up with major defects creating a great technical challenge for the operating surgeon. We present a novel technique and operative algorithm for the management of chronic TAT ruptures with a major gap after a delayed diagnosis not otherwise correctable with currently described techniques in the literature. This technique has been performed in 4 cases without any complications with fairly successful functional outcomes. For the reconstruction of chronic TAT rupture with an average delay of nine weeks after initial injury and gap of greater than 10 cm, a thorough operative algorithm was implemented in 4 patients using a double bundle gracilis allograft. Patients were then kept nonweightbearing for 6 weeks followed by weightbearing as tolerated. They began physical therapy with a focus on ankle exercises and gradual return to normal activity at 8 weeks, with resistance training exercises allowed at 12 weeks. At a mean follow-up time of 24.5 months, all patients reported significant pain relief with normal gait pattern. There were no reported intra- or postoperative complications. The average Foot and Ankle Ability Measure score increased to 90 from 27.5 in the postoperative period. All patients were able to return their previous activity levels. Gracilis allograft reconstruction as used in this study is a viable and reproducible alternative to primary repair with postoperative results being favorable without using complex tendon transfer techniques or autograft use necessitating the functional sacrifice of transferred or excised tendon. To the best of our knowledge, this is the first study demonstrating a successful technique and operative algorithm of gracilis allograft reconstruction of the TAT

  13. Anterior knee pain.

    PubMed

    LLopis, Eva; Padrón, Mario

    2007-04-01

    Anterior knee pain is a common complain in all ages athletes. It may be caused by a large variety of injuries. There is a continuum of diagnoses and most of the disorders are closely related. Repeated minor trauma and overuse play an important role for the development of lesions in Hoffa's pad, extensor mechanism, lateral and medial restrain structures or cartilage surface, however usually an increase or change of activity is referred. Although the direct relation of cartilage lesions, especially chondral, and pain is a subject of debate these lesions may be responsible of early osteoarthrosis and can determine athlete's prognosis. The anatomy and biomechanics of patellofemoral joint is complex and symptoms are often unspecific. Transient patellar dislocation has MR distinct features that provide evidence of prior dislocation and rules our complication. However, anterior knee pain more often is related to overuse and repeated minor trauma. Patella and quadriceps tendon have been also implicated in anterior knee pain, as well as lateral or medial restraint structures and Hoffa's pad. US and MR are excellent tools for the diagnosis of superficial tendons, the advantage of MR is that permits to rule out other sources of intraarticular derangements. Due to the complex anatomy and biomechanic of patellofemoral joint maltracking is not fully understood; plain films and CT allow the study of malalignment, new CT and MR kinematic studies have promising results but further studies are needed. Our purpose here is to describe how imaging techniques can be helpful in precisely defining the origin of the patient's complaint and thus improve understanding and management of these injuries.

  14. A study of bacterial flagellar bundling.

    PubMed

    Flores, Heather; Lobaton, Edgar; Méndez-Diez, Stefan; Tlupova, Svetlana; Cortez, Ricardo

    2005-01-01

    Certain bacteria, such as Escherichia coli (E. coli) and Salmonella typhimurium (S. typhimurium), use multiple flagella often concentrated at one end of their bodies to induce locomotion. Each flagellum is formed in a left-handed helix and has a motor at the base that rotates the flagellum in a corkscrew motion. We present a computational model of the flagellar motion and their hydrodynamic interaction. The model is based on the equations of Stokes flow to describe the fluid motion. The elasticity of the flagella is modeled with a network of elastic springs while the motor is represented by a torque at the base of each flagellum. The fluid velocity due to the forces is described by regularized Stokeslets and the velocity due to the torques by the associated regularized rotlets. Their expressions are derived. The model is used to analyze the swimming motion of a single flagellum and of a group of three flagella in close proximity to one another. When all flagellar motors rotate counterclockwise, the hydrodynamic interaction can lead to bundling. We present an analysis of the flow surrounding the flagella. When at least one of the motors changes its direction of rotation, the same initial conditions lead to a tumbling behavior characterized by the separation of the flagella, changes in their orientation, and no net swimming motion. The analysis of the flow provides some intuition for these processes.

  15. Nursing Care Management: Influence on Bundled Payments.

    PubMed

    Lentz, Shaynie; Luther, Brenda

    Fragmented and uncoordinated care is the third highest driver of U.S. healthcare costs. Although less than 10% of patients experience uncoordinated care, these patients represent 36% of total healthcare costs; care management interaction makes a significant impact on the utilization of healthcare dollars. A literature search was conducted to construct a model of care coordination for elective surgical procedures by collecting best practices for acute, transitions, and post-acute care periods. A case study was used to demonstrate the model developed. Care management defines care coordination as a model of care to address improving patient and caregiver engagement, communication across settings of care, and ultimately improved patient outcomes of care. Nurse-led care coordination in the presurgical, inpatient, and post-acute care settings requires systems change and administrative support to effectively meet the goals of the Affordable Care Act of reducing redundancy and costs while improving the patient experience. Nursing is the lynchpin of care management processes in all settings of care; thus, this model of care coordination for elective surgical admissions can provide nursing care management leaders a comprehensive view of coordinating care for these patient across settings of care during the predetermined time period of care. As bundled payment structures increasingly affect hospital systems, nursing leaders need to be ready to create or improve their care management processes; care coordination is one such process requiring immediate attention.

  16. Controlled production of aligned-nanotube bundles

    NASA Astrophysics Data System (ADS)

    Terrones, M.; Grobert, N.; Olivares, J.; Zhang, J. P.; Terrones, H.; Kordatos, K.; Hsu, W. K.; Hare, J. P.; Townsend, P. D.; Prassides, K.; Cheetham, A. K.; Kroto, H. W.; Walton, D. R. M.

    1997-07-01

    Carbon nanotubes might be usefully employed in nanometre-scale engineering and electronics. Electrical conductivity measurements on the bulk material, on individual multi-walled and single-walled nanotubes and on bundles of single-walled nanotubes have revealed that they may behave as metallic, insulating or semiconducting nanowires, depending on the method of production-which controls the degree of graphitization, the helicity and the diameter. Measurements of Young's modulus show that single nanotubes are stiffer than commercial carbon fibres. Methods commonly used to generate nanotubes-carbon-arc discharge techniques, catalytic pyrolysis of hydrocarbons and condensed-phase electrolysis-generally suffer from the drawbacks that polyhedral particles are also formed and that the dimensions of the nanotubes are highly variable. Here we describe a method for generating aligned carbon nanotubes by pyrolysis of 2-amino-4,6-dichloro-s-triazine over thin films of a cobalt catalyst patterned on a silica substrate by laser etching. The use of a patterned catalyst apparently encourages the formation of aligned nanotubes. The method offers control over length (up to about 50μm) and fairly uniform diameters (30-50nm), as well as producing nanotubes in high yield, uncontaminated by polyhedral particles.

  17. Concise Care Bundles In Acute Medicine

    PubMed Central

    Kivlin, Jude; Altemimi, Harith

    2015-01-01

    The Queen Elizabeth Hospital in King's Lynn, Norfolk is a 488 bed hospital providing services to approximately 331,000 people across 750 square miles. In 2012 a need was recognised for documentation (pathways) in a practical format to increase usage of national guidelines and facilitate adherence to best practice (gold standards of care) that could be easily version controlled, auditable and provide support in clinical decision-making by junior doctors. BMJ Action Sets[1] fulfilled the brief with expert knowledge, version control and support, though they were deemed too lengthy and unworkable in fast paced settings like the medical assessment unit; they formed the base creation of concise care bundles (CCB). CCB were introduced for 21 clinical presentations and one procedure. Outcomes were fully audited and showed significant improvement in a range of measures, including an increase in completions of CHADVASC score in atrial fibrillation, antibiotics prescribed per protocol in chronic obstructive pulmonary disease (COPD), and Blatchford score recorded for patients presenting with upper gastrointestinal bleed. PMID:26734437

  18. Correlation of expression of the actin filament-bundling protein espin with stereociliary bundle formation in the developing inner ear.

    PubMed

    Li, Huawei; Liu, Hong; Balt, Steve; Mann, Sabine; Corrales, C Eduardo; Heller, Stefan

    2004-01-01

    The vertebrate hair cell is named for its stereociliary bundle or hair bundle that protrudes from the cell's apical surface. Hair bundles mediate mechanosensitivity, and their highly organized structure plays a critical role in mechanoelectrical transduction and amplification. The prototypical hair bundle is composed of individual stereocilia, 50-300 in number, depending on the animal species and on the type of hair cell. The assembly of stereocilia, in particular, the formation during development of individual rows of stereocilia with descending length, has been analyzed in great morphological detail. Electron microscopic studies have demonstrated that stereocilia are filled with actin filaments that are rigidly cross-linked. The growth of individual rows of stereocilia is associated with the addition of actin filaments and with progressively increasing numbers of cross-bridges between actin filaments. Recently, a mutation in the actin filament-bundling protein espin has been shown to underlie hair bundle degeneration in the deaf jerker mouse, subsequently leading to deafness. Our study was undertaken to investigate the appearance and developmental expression of espin in chicken inner ear sensory epithelia. We found that the onset of espin expression correlates with the initiation and growth of stereocilia bundles in vestibular and cochlear hair cells. Intense espin immunolabeling of stereocilia was colocalized with actin filament staining in all types of hair cells at all developmental stages and in adult animals. Our analysis of espin as a molecular marker for actin filament cross-links in stereocilia is in full accordance with previous morphological studies and implicates espin as an important structural component of hair bundles from initiation of bundle assembly to mature chicken hair cells.

  19. Anterior vitrectomy for shallow anterior chamber after cataract extraction.

    PubMed

    Dottan, S; Levartovsky, S; Oliver, M

    1982-06-01

    Pars plana anterior vitrectomy was performed in 9 patients with shallow anterior chamber after cataract extraction. Five patients had choroidal and/or ciliary body effusion (CCBE), and 4 had aphakic pupillary block (APB). Vitrectomy was performed only after medical treatment failed to restore a normal anterior chamber depth. In all patients the anterior chamber restored during surgery and remained so thereafter, although in patients with CCBE, the fundal pathology subsided days or even months later. The only surgical complication was a longstanding cystoid macular oedema in one patient. Pars plana vitrectomy would appear to have advantages over other surgical techniques, in similar circumstances.

  20. Bundles of Norms About Teen Sex and Pregnancy.

    PubMed

    Mollborn, Stefanie; Sennott, Christie

    2015-09-01

    Teen pregnancy is a cultural battleground in struggles over morality, education, and family. At its heart are norms about teen sex, contraception, pregnancy, and abortion. Analyzing 57 interviews with college students, we found that "bundles" of related norms shaped the messages teens hear. Teens did not think their communities encouraged teen sex or pregnancy, but normative messages differed greatly, with either moral or practical rationalizations. Teens readily identified multiple norms intended to regulate teen sex, contraception, abortion, childbearing, and the sanctioning of teen parents. Beyond influencing teens' behavior, norms shaped teenagers' public portrayals and post hoc justifications of their behavior. Although norm bundles are complex to measure, participants could summarize them succinctly. These bundles and their conflicting behavioral prescriptions create space for human agency in negotiating normative pressures. The norm bundles concept has implications for teen pregnancy prevention policies and can help revitalize social norms for understanding health behaviors. © The Author(s) 2014.

  1. National Partnership for Maternal Safety: Consensus Bundle on Obstetric Hemorrhage.

    PubMed

    Main, Elliott K; Goffman, Dena; Scavone, Barbara M; Low, Lisa Kane; Bingham, Debra; Fontaine, Patricia L; Gorlin, Jed B; Lagrew, David C; Levy, Barbara S

    2015-07-01

    Hemorrhage is the most frequent cause of severe maternal morbidity and preventable maternal mortality and therefore is an ideal topic for the initial national maternity patient safety bundle. These safety bundles outline critical clinical practices that should be implemented in every maternity unit. They are developed by multidisciplinary work groups of the National Partnership for Maternal Safety under the guidance of the Council on Patient Safety in Women's Health Care. The safety bundle is organized into four domains: Readiness, Recognition and Prevention, Response, and Reporting and System Learning. Although the bundle components may be adapted to meet the resources available in individual facilities, standardization within an institution is strongly encouraged. References contain sample resources and "Potential Best Practices" to assist with implementation.

  2. National Partnership for Maternal Safety Consensus Bundle on Obstetric Hemorrhage.

    PubMed

    Main, Elliott K; Goffman, Dena; Scavone, Barbara M; Low, Lisa Kane; Bingham, Debra; Fontaine, Patricia L; Gorlin, Jed B; Lagrew, David C; Levy, Barbara S

    2015-01-01

    Hemorrhage is the most frequent cause of severe maternal morbidity and preventable maternal mortality and therefore is an ideal topic for the initial national maternity patient safety bundle. These safety bundles outline critical clinical practices that should be implemented in every maternity unit. They are developed by multidisciplinary work groups of the National Partnership for Maternal Safety under the guidance of the Council on Patient Safety in Women's Health Care. The safety bundle is organized into 4 domains: Readiness, Recognition and Prevention, Response, and Reporting and Systems Learning. Although the bundle components may be adapted to meet the resources available in individual facilities, standardization within an institution is strongly encouraged. References contain sample resources and "Potential Best Practices" to assist with implementation.

  3. National Partnership for Maternal Safety: consensus bundle on obstetric hemorrhage.

    PubMed

    Main, Elliott K; Goffman, Dena; Scavone, Barbara M; Low, Lisa Kane; Bingham, Debra; Fontaine, Patricia L; Gorlin, Jed B; Lagrew, David C; Levy, Barbara S

    2015-07-01

    Hemorrhage is the most frequent cause of severe maternal morbidity and preventable maternal mortality and therefore is an ideal topic for the initial national maternity patient safety bundle. These safety bundles outline critical clinical practices that should be implemented in every maternity unit. They are developed by multidisciplinary work groups of the National Partnership for Maternal Safety under the guidance of the Council on Patient Safety in Women's Health Care. The safety bundle is organized into four domains: Readiness, Recognition and Prevention, Response, and Reporting and System Learning. Although the bundle components may be adapted to meet the resources available in individual facilities, standardization within an institution is strongly encouraged. References contain sample resources and "Potential Best Practices" to assist with implementation.

  4. 15. VIEW OF SHINGLES BUNDLED, PLACED ON PALLET, AND READIED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. VIEW OF SHINGLES BUNDLED, PLACED ON PALLET, AND READIED FOR FORKLIFT OPERATOR TO MOVE PALLET OF SHINGLES TO LOADING DOCK - Lester Shingle Mill, 1602 North Eighteenth Street, Sweet Home, Linn County, OR

  5. SEU43 fuel bundle shielding analysis during spent fuel transport

    SciTech Connect

    Margeanu, C. A.; Ilie, P.; Olteanu, G.

    2006-07-01

    The basic task accomplished by the shielding calculations in a nuclear safety analysis consist in radiation doses calculation, in order to prevent any risks both for personnel protection and impact on the environment during the spent fuel manipulation, transport and storage. The paper investigates the effects induced by fuel bundle geometry modifications on the CANDU SEU spent fuel shielding analysis during transport. For this study, different CANDU-SEU43 fuel bundle projects, developed in INR Pitesti, have been considered. The spent fuel characteristics will be obtained by means of ORIGEN-S code. In order to estimate the corresponding radiation doses for different measuring points the Monte Carlo MORSE-SGC code will be used. Both codes are included in ORNL's SCALE 5 programs package. A comparison between the considered SEU43 fuel bundle projects will be also provided, with CANDU standard fuel bundle taken as reference. (authors)

  6. Effects of Tau on Flow-Aligned Microtubule Bundles

    NASA Astrophysics Data System (ADS)

    Ross, Jennifer L.; Kuchnir Fygenson, D.

    2003-03-01

    Microtubules are cylindrical crystals of the protein tubulin with 17nm inner diameter and 25nm outer diameter. Recent structural studies suggest that the microtubule wall may be porous to small molecules. We have investigated the mobility of molecules in bundles of flow aligned microtubules. We find the spacing between the microtubules in the bundle is increased by the addition of tau, a microtubule associated protein. In the absence of tau, flow can be used to make tightly packed bundles of microtubules. Adding tau causes the tight bundles to swell and separate. We use fluorescence recovery after photobleaching (FRAP) to quantify the mobility of a taxol, a small drug that binds to the microtubule interior.

  7. Improved Conjugate Gradient Bundle Adjustment of Dunhuang Wall Painting Images

    NASA Astrophysics Data System (ADS)

    Hu, K.; Huang, X.; You, H.

    2017-09-01

    Bundle adjustment with additional parameters is identified as a critical step for precise orthoimage generation and 3D reconstruction of Dunhuang wall paintings. Due to the introduction of self-calibration parameters and quasi-planar constraints, the structure of coefficient matrix of the reduced normal equation is banded-bordered, making the solving process of bundle adjustment complex. In this paper, Conjugate Gradient Bundle Adjustment (CGBA) method is deduced by calculus of variations. A preconditioning method based on improved incomplete Cholesky factorization is adopt to reduce the condition number of coefficient matrix, as well as to accelerate the iteration rate of CGBA. Both theoretical analysis and experimental results comparison with conventional method indicate that, the proposed method can effectively conquer the ill-conditioned problem of normal equation and improve the calculation efficiency of bundle adjustment with additional parameters considerably, while maintaining the actual accuracy.

  8. A macroscopic scale model of bacterial flagellar bundling

    PubMed Central

    Kim, MunJu; Bird, James C.; Van Parys, Annemarie J.; Breuer, Kenneth S.; Powers, Thomas R.

    2003-01-01

    Escherichia coli and other bacteria use rotating helical filaments to swim. Each cell typically has about four filaments, which bundle or disperse depending on the sense of motor rotation. To study the bundling process, we built a macroscopic scale model consisting of stepper motor-driven polymer helices in a tank filled with a high-viscosity silicone oil. The Reynolds number, the ratio of viscous to elastic stresses, and the helix geometry of our experimental model approximately match the corresponding quantities of the full-scale E. coli cells. We analyze digital video images of the rotating helices to show that the initial rate of bundling is proportional to the motor frequency and is independent of the characteristic relaxation time of the filament. We also determine which combinations of helix handedness and sense of motor rotation lead to bundling. PMID:14671319

  9. Assembly of mm-scale macrobridges with carbon nanotube bundles

    NASA Astrophysics Data System (ADS)

    Cao, Anyuan; Ajayan, P. M.; Ramanath, G.

    2003-07-01

    We report a chemical vapor deposition method for in situ bridging of mm-scale metal-contact patterns with bundles of multiwalled carbon nanotubes. The nanotube bundles synthesized from a hexane-ferrocene-thiophene mixture have a diameter of <50 μm and lengths up to millimeters, typically consisting of tens to hundreds of aligned nanotubes. These bundles are transported to the downstream end of the furnace, where they are captured by relief patterns of metal-contact tips. We can control the orientation and length of the nanotube bridges by preorganizing the metal tips to receive the bundles. This method is amenable to both scaling up, e.g., to create large-area arrays of nanotubes with contact electrodes, as well as scaling down, e.g., to bridge closely spaced contact structures.

  10. Uveitis (acute anterior).

    PubMed

    Islam, Niaz; Pavesio, Carlos

    2010-04-08

    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. 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). 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. 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.

  11. Unified description of interactions in terms of composite fiber bundles

    NASA Astrophysics Data System (ADS)

    Tresguerres, Romualdo

    2002-09-01

    We claim that a composite fiber bundle satisfactorily serves as the geometrical structure underlying gauge theories of spacetime groups, such as the Poincaré gauge theory. A trivial extension of the approach to include internal symmetries also provides a unique mathematical scheme in which gravitation and the remaining forces are put together and treated in a common fiber bundle language. The result is a homogeneous characterization of interactions, gravity included, exclusively by means of connections.

  12. Performance-based bundled payments: potential benefits and burdens.

    PubMed

    Satin, David J; Miles, Justin

    2009-10-01

    Performance-based bundled payments have emerged as the most recent iteration of pay for performance. These are programs in which providers are paid a single fee for a set of evidenced-based services related to a diagnosis. The payments are typically linked to outcomes as well as other quality measures. This paper reviews two prominent bundled payment programs--PROMETHEUS and ProvenCare--and discusses the potential pitfalls of these approaches.

  13. Generalized holomorphic bundles and the B-field action

    NASA Astrophysics Data System (ADS)

    Hitchin, Nigel

    2011-01-01

    On a generalized complex manifold, there is an associated definition of a generalized holomorphic bundle, introduced by Gualtieri. In the case of an ordinary complex structure, this notion yields an object which we call a co-Higgs bundle, and we consider the B-field action of a closed form of type (1,1), both local and global. The effect makes contact with both Nahm's equations and holomorphic gerbes.

  14. The evaluation of muscle recovery after anatomical single-bundle ACL reconstruction using a quadriceps autograft.

    PubMed

    Iriuchishima, Takanori; Ryu, Keinosuke; Okano, Tatsumasa; Suruga, Makoto; Aizawa, Shin; Fu, Freddie H

    2017-05-01

    The purpose of this study was to reveal the degree of muscle recovery and report the clinical results of anatomical single-bundle ACL reconstruction using a quadriceps autograft. Twenty subjects undergoing anatomical single-bundle ACL reconstruction using a quadriceps autograft were included in this study. A 5-mm-wide, 8-cm-long graft, involving the entire layer of the quadriceps tendon, was harvested without bone block. The average graft diameter was 8.1 ± 1.4 mm. An initial tension of 30 N was applied. The femoral tunnel was created from the far-medial portal. Each femoral and tibial tunnel was created close to the antero-medial bundle insertion site. For the evaluation of muscle recovery (quadriceps and hamstring), a handheld dynamometer was used. The evaluation of muscle recovery was performed pre-operatively, and at 3, 6, 9, and 12 months after surgery. Muscle recovery data were calculated as a percentage of leg strength in the non-operated leg. Anterior tibial translation (ATT), pivot shift test, and IKDC score were evaluated. The average quadriceps strength pre-operatively, and at 3, 6, 9, and 12 months after ACL reconstruction was 90.5 ± 19, 67.8 ± 21.4, 84 ± 17.5, and 85.1 ± 12.6 %, respectively. The average hamstring strength pre-operatively, and at 3, 6, 9, and 12 months after ACL reconstruction was 99.5 ± 13.7, 78.7 ± 11.4, 90.5 ± 19, and 96.7 ± 13.8 %, respectively. ATT pre-operatively and at 12 months after surgery was 5.4 ± 1.3 and 1.0 ± 0.8 mm, respectively. No subjects exhibited positive pivot shift after surgery. Within 6 months following surgery, quadriceps hypotrophy was observed in all subjects. However, the hypotrophy had recovered at 12 months following surgery. No subjects complained of donor site pain after surgery. Anatomical single-bundle ACL reconstruction using a quadriceps autograft resulted in equivalent level of muscle recovery and knee stability when compared with previously reported ACL

  15. Optical system design of subminiature endoscope with imaging fiber bundle

    NASA Astrophysics Data System (ADS)

    Lv, Juan; Xue, Bin; Li, Ting; He, Ying-hong; Ma, Xiao-long; Yan, Xing-tao

    2016-10-01

    A new subminiature endoscope which used for reconnaissance and diagnosis has been designed. This subminiature endoscope is designed based on imaging fiber bundle and consist of the front object lens whose aperture is only 0.5mm, imaging fiber bundle and the post coupling lens. It realized by using subminiature optical systems . The FOV(field of view) and the focal length of the front object lens are 50° and 0.59mm. And the object distance, F number and detected imaging high of the front object lens are 3mm, 6 and 0.5mm. The total number of the imaging fiber bundle are 10000 and it's pixel cell size is 5 μm. The effective aperture of the imaging fiber bundle is 0.46mm. The post coupling lens has a reduction ratio of 1.73. It's object distance and imaging height are 5mm and 0.8mm. The Numerical Aperture (NA) of the front object lens, imaging fiber bundle and the post coupling lens are matching will. The coupling efficiency of the imaging fiber bundle is above 93% and the system's design result can meet the need of the limit resolution of the imaging fiber. This kind of the fiber endoscope has the peculiarity of wide FOV, fine imaging quality, compact configuration, low finished cost and etc. It is meaningful to realize the objective of miniaturization, batch-type production and high imaging quality of the endoscope.

  16. Tapered fiber bundles for combining high-power diode lasers.

    PubMed

    Kosterin, Andrey; Temyanko, Valery; Fallahi, Mahmoud; Mansuripur, Masud

    2004-07-01

    Tapered fiber bundles are often used to combine the output power of several semiconductor lasers into a multimode optical fiber for the purpose of pumping fiber lasers and amplifiers. It is generally recognized that the brightness of such combiners does not exceed the brightness of the individual input fibers. We report that the brightness of the tapered fibers (and fiber bundles) depends on both the taper ratio and the mode-filling properties of the beams launched into the individual fibers. Brightness, therefore, can be increased by selection of sources that fill a small fraction of the input fiber's modal capacity. As proof of concept, we present the results of measurements on tapered fiber-bundle combiners having a low-output étendue. Under low mode-filling conditions per input multimode fiber (i.e., fraction of filled modes < or =0.29), we report brightness enhancements of 8.0 dB for 19 x 1 bundles, 6.7 dB for 7 x 1 bundles, and 4.0 dB for 3 x 1 combiners. Our measured coupling efficiency variations of approximately 1%-2% among the various fibers in a given bundle confirm the uniformity and quality of the fabricated devices.

  17. Plantain fibre bundles isolated from Colombian agro-industrial residues.

    PubMed

    Gañán, Piedad; Zuluaga, Robin; Restrepo, Adriana; Labidi, Jalel; Mondragon, Iñaki

    2008-02-01

    Comestible fruit production from Musaceas plants is an important economical activity in developing countries like Colombia. However, it generates a large amount of agro-industrial residues. Some of them are a potential resource of natural fibres, which can be used as reinforcement for composite materials. In this work, a series of commercial plantain (Musa AAB, cv "Dominico Harton") fibre bundles extracted from pseudostem, leaf sheath and rachis agricultural wastes were analyzed. Mechanical decortication and biological retting processes were used during fiber extraction. No significant differences in composition of vascular bundles were observed for both extraction processes. Gross morphological characteristics and mechanical behavior have been evaluated. Conducting tissues with spiral-like arrangement are observed attached to fibre bundles. This fact suggests a big amount of these tissues in commercial plantain plants. Both used extraction methods are not enough to remove them. Pseudostem fibre bundles have higher specific strength and modulus and lower strain at break than leaf sheath and rachis fibre bundles, having values comparable to other lignocellulosic fibres bundles.

  18. Laser speckle imaging of atherosclerotic plaques through optical fiber bundles

    PubMed Central

    Nadkarni, Seemantini K.; Bouma, Brett E.; Yelin, Dvir; Gulati, Amneet; Tearney, Guillermo J.

    2009-01-01

    Laser speckle imaging (LSI), a new technique that measures an index of plaque viscoelasticity, has been investigated recently to characterize atherosclerotic plaques. These prior studies demonstrated the diagnostic potential of LSI for detecting high-risk plaques and were conducted ex vivo. To conduct intracoronary LSI in vivo, the laser speckle pattern must be transmitted from the coronary wall to the image detector in the presence of cardiac motion. Small-diameter, flexible optical fiber bundles, similar to those used in coronary angioscopy, may be incorporated into an intravascular catheter for this purpose. A key challenge is that laser speckle is influenced by inter-fiber leakage of light, which may be exacerbated during bundle motion. In this study, we tested the capability of optical fiber bundles to transmit laser speckle patterns obtained from atherosclerotic plaques and evaluated the influence of motion on the diagnostic accuracy of fiber bundle-based LSI. Time-varying helium-neon laser speckle images of aortic plaques were obtained while cyclically moving the flexible length of the bundle to mimic coronary motion. Our results show that leached fiber bundles may reliably transmit laser speckle images in the presence of cardiac motion, providing a viable option to conduct intracoronary LSI. PMID:19021396

  19. Hydraulic testing of accelerator-production-of-tritium rod bundles

    SciTech Connect

    Spatz, T.L.; Siebe, D.A.

    1999-01-01

    Hydraulic tests have been performed on small pitch-to-diameter-ratio rod bundles using light water (1.7 < P/D < 1.17, and d = 3.175 mm). Flows cover the range from greater-than-nominal Reynolds numbers (fully turbulent) to low-speed laminar flows. Differential pressure measurements were made across the support plates holding the rod bundles, across the rod bundles, and across the entire assembly. Flow rates, temperatures, and gauge pressures also were measured. The data from these hydraulic tests have been compared to correlating literature for tightly pitched rod bundles. The prototypic geometry of these tests did not compare directly to any geometry found in the literature because of the variety of subchannels along the outer wall of the rod bundle. Under that constraint, there was excellent comparison of the rod-bundle friction factor with those factors given in the literature. The results show a large range of the Reynolds number over which the flow is in transition from laminar to turbulent (e.g., 580 < Re{sub Tr} < 13,000). Also presented is the comparison of the overall rung pressure drop to a solution based on hydraulic-resistance handbook calculations.

  20. Scheimpflug imaging in anterior megalophthalmos

    PubMed Central

    Nemeth, Gabor; Hassan, Ziad; Berta, Andras; Modis, Laszlo

    2013-01-01

    We report an anterior megalophthalmos case with decreased corneal thickness and show the findings using Scheimpflug imaging. A 25-year-old male was diagnosed with anterior megalophthalmos. In both eyes, enlarged corneal length was measured. Beside a comparatively good visual acuity, a thin but clear cornea, a fairly deep anterior chamber, and central lens opacity were found. Scheimpflug images were taken using Pentacam HR. Scheimpflug-based imaging can provide us new data at the examination of this syndrome affecting the whole anterior segment. PMID:23275220

  1. A compactification of the moduli space of principal Higgs bundles over singular curves

    NASA Astrophysics Data System (ADS)

    Lo Giudice, Alessio; Pustetto, Andrea

    2016-12-01

    A principal Higgs bundle (P , ϕ) over a singular curve X is a pair consisting of a principal bundle P and a morphism ϕ : X →Ad P ⊗ ΩX1. We construct the moduli space of principal Higgs G-bundles over an irreducible singular curve X using the theory of decorated vector bundles. More precisely, given a faithful representation ρ : G → Sl(V) of G, we consider principal Higgs bundles as triples (E , q , φ) , where E is a vector bundle with rk(E) = dim V over the normalization X ˜ of X, q is a parabolic structure on E and φ :Ea,b → L is a morphism of bundles, L being a line bundle and Ea,b ≑(E⊗a) ⊕ b a vector bundle depending on the Higgs field ϕ and on the principal bundle structure.

  2. 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.

  3. Combustor having mixing tube bundle with baffle arrangement for directing fuel

    DOEpatents

    Hughes, Michael John; McConnaughhay, Johnie Franklin

    2016-08-23

    A combustor includes a tube bundle that extends radially across at least a portion of the combustor. The tube bundle includes an upstream surface axially separated from a downstream surface, and a plurality of tubes extend from the upstream surface through the downstream surface to provide fluid communication through the tube bundle. A barrier extends radially inside the tube bundle between the upstream and downstream surfaces, and a baffle extends axially inside the tube bundle between the upstream surface and the barrier.

  4. Histones bundle F-actin filaments and affect actin structure.

    PubMed

    Blotnick, Edna; Sol, Asaf; Muhlrad, Andras

    2017-01-01

    Histones are small polycationic proteins complexed with DNA located in the cell nucleus. Upon apoptosis they are secreted from the cells and react with extracellular polyanionic compounds. Actin which is a polyanionic protein, is also secreted from necrotic cells and interacts with histones. We showed that both histone mixture (histone type III) and the recombinant H2A histone bundles F-actin, increases the viscosity of the F-actin containing solution and polymerizes G-actin. The histone-actin bundles are relatively insensitive to increase of ionic strength, unlike other polycation, histatin, lysozyme, spermine and LL-37 induced F-actin bundles. The histone-actin bundles dissociate completely only in the presence of 300-400 mM NaCl. DNA, which competes with F-actin for histones, disassembles histone induced actin bundles. DNase1, which depolymerizes F- to G-actin, actively unbundles the H2A histone induced but slightly affects the histone mixture induced actin bundles. Cofilin decreases the amount of F-actin sedimented by low speed centrifugation, increases light scattering and viscosity of F-actin-histone mixture containing solutions and forms star like superstructures by copolymerizing G-actin with H2A histone. The results indicate that histones are tightly attached to F-actin by strong electrostatic and hydrophobic forces. Since both histones and F-actin are present in the sputum of patients with cystic fibrosis, therefore, the formation of the stable histone-actin bundles can contribute to the pathology of this disease by increasing the viscosity of the sputum. The actin-histone interaction in the nucleus might affect gene expression.

  5. Numerical modeling of anisotropic fiber bundle behavior in oxygenators.

    PubMed

    Bhavsar, Sonya S; Schmitz-Rode, Thomas; Steinseifer, Ulrich

    2011-11-01

    Prediction of flow patterns through oxygenator fiber bundles can allow shape optimization so that efficient gas exchange occurs with minimal thrombus formation and hemolysis. Computational fluid dynamics (CFD) simulations can be used to predict three-dimensional flow velocities and flow distribution from spatially dependent variables and they allow estimations of erythrocyte residence time within the fiber bundle. This study builds upon previous work to develop an accurate numerical model for oxygenators, which would allow for accelerated iterations in oxygenator shape and diffuser plate design optimization. Hollow fiber flow channels were developed to permit experimental calculation of fluid permeability in two directions: main flow along the hollow fiber and perpendicular to the hollow fibers. Commercial software was used to develop three-dimensional CFD models of the experimental flow channels and an anisotropic porous media model for oxygenators from these experimental results. The oxygenator model was used to predict pressure loss throughout the device, visualize blood distribution within the fiber bundle, and estimate erythrocyte residence time within the bundle. Experimental flow channels measurements produced a streamwise permeability of 1.143e(-8) m(2) and transverse permeability of 2.385e(-9) m(2) . These permeabilities, coupled with previous work with volume porosity, were used to develop the numerical model of anisotropic behavior through porous fiber bundles, which indicated a more uniform flow field throughout the oxygenator. Incorporation of known anisotropic fiber bundle behavior in previous numerical models more accurately represents fluid behavior through an oxygenator fiber bundle. CFD coupled with experimental validation can produce a powerful tool for oxygenator design and development.

  6. [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.

  7. The effect of anterior cruciate ligament reconstruction on kinematics of the knee with combined anterior cruciate ligament injury and subtotal medial meniscectomy: an in vitro robotic investigation.

    PubMed

    Seon, Jong Keun; Gadikota, Hemanth R; Kozanek, Michal; Oh, Luke S; Gill, Thomas J; Li, Guoan

    2009-02-01

    The aims of this study were to determine: (1) the kinematic effect of subtotal medial meniscectomy on the anterior cruciate ligament (ACL)-deficient knee and (2) the effect of ACL reconstruction on kinematics of the knee with combined ACL deficiency and subtotal medial meniscectomy under anterior tibial and simulated quadriceps loads. Eight human cadaveric knees were sequentially tested using a robotic testing system under 4 conditions: intact, ACL deficiency, ACL deficiency with subtotal medial meniscectomy, and single-bundle ACL reconstruction using a bone-patellar tendon-bone graft. Knee kinematics were measured at 0 degrees, 15 degrees, 30 degrees, 60 degrees, and 90 degrees of flexion under an anterior tibial load of 130 N and a quadriceps muscle load of 400 N. Subtotal medial meniscectomy in the ACL-deficient knee significantly increased anterior and lateral tibial translations under the anterior tibial and quadriceps loads (P < .05). These kinematic changes were larger at high flexion (>or=60 degrees) than at low flexion angles. ACL reconstruction in knees with ACL deficiency and subtotal medial meniscectomy significantly reduced the increased anterior tibial translation, but could not restore anterior translation to the intact level with differences ranging from 2.6 mm at 0 degrees to 5.5 mm at 30 degrees of flexion. ACL reconstruction did not significantly affect the medial-lateral translation and internal-external tibial rotation in the presence of subtotal meniscectomy. Subtotal medial meniscectomy in knees with ACL deficiency altered knee kinematics, especially at high flexion angles. ACL reconstruction significantly reduced the increased tibial translation in knees with combined ACL deficiency and subtotal medial meniscectomy, but could not restore the knee kinematics to the intact knee level. This study suggests that meniscus is an important secondary stabilizer against anterior and lateral tibial translations and should be preserved in the setting of

  8. Verification of the FBR fuel bundle-duct interaction analysis code BAMBOO by the out-of-pile bundle compression test with large diameter pins

    NASA Astrophysics Data System (ADS)

    Uwaba, Tomoyuki; Ito, Masahiro; Nemoto, Junichi; Ichikawa, Shoichi; Katsuyama, Kozo

    2014-09-01

    The BAMBOO computer code was verified by results for the out-of-pile bundle compression test with large diameter pin bundle deformation under the bundle-duct interaction (BDI) condition. The pin diameters of the examined test bundles were 8.5 mm and 10.4 mm, which are targeted as preliminary fuel pin diameters for the upgraded core of the prototype fast breeder reactor (FBR) and for demonstration and commercial FBRs studied in the FaCT project. In the bundle compression test, bundle cross-sectional views were obtained from X-ray computer tomography (CT) images and local parameters of bundle deformation such as pin-to-duct and pin-to-pin clearances were measured by CT image analyses. In the verification, calculation results of bundle deformation obtained by the BAMBOO code analyses were compared with the experimental results from the CT image analyses. The comparison showed that the BAMBOO code reasonably predicts deformation of large diameter pin bundles under the BDI condition by assuming that pin bowing and cladding oval distortion are the major deformation mechanisms, the same as in the case of small diameter pin bundles. In addition, the BAMBOO analysis results confirmed that cladding oval distortion effectively suppresses BDI in large diameter pin bundles as well as in small diameter pin bundles.

  9. External Verification of the Bundle Adjustment in Photogrammetric Software Using the Damped Bundle Adjustment Toolbox

    NASA Astrophysics Data System (ADS)

    Börlin, Niclas; Grussenmeyer, Pierre

    2016-06-01

    The aim of this paper is to investigate whether the Matlab-based Damped Bundle Adjustment Toolbox (DBAT) can be used to provide independent verification of the BA computation of two popular software—PhotoModeler (PM) and PhotoScan (PS). For frame camera data sets with lens distortion, DBAT is able to reprocess and replicate subsets of PM results with high accuracy. For lens-distortion-free data sets, DBAT can furthermore provide comparative results between PM and PS. Data sets for the discussed projects are available from the authors. The use of an external verification tool such as DBAT will enable users to get an independent verification of the computations of their software. In addition, DBAT can provide computation of quality parameters such as estimated standard deviations, correlation between parameters, etc., something that should be part of best practice for any photogrammetric software. Finally, as the code is free and open-source, users can add computations of their own.

  10. Time-dependent fiber bundles with local load sharing.

    PubMed

    Newman, W I; Phoenix, S L

    2001-02-01

    Fiber bundle models, where fibers have random lifetimes depending on their load histories, are useful tools in explaining time-dependent failure in heterogeneous materials. Such models shed light on diverse phenomena such as fatigue in structural materials and earthquakes in geophysical settings. Various asymptotic and approximate theories have been developed for bundles with various geometries and fiber load-sharing mechanisms, but numerical verification has been hampered by severe computational demands in larger bundles. To gain insight at large size scales, interest has returned to idealized fiber bundle models in 1D. Such simplified models typically assume either equal load sharing (ELS) among survivors, or local load sharing (LLS) where a failed fiber redistributes its load onto its two nearest flanking survivors. Such models can often be solved exactly or asymptotically in increasing bundle size, N, yet still capture the essence of failure in real materials. The present work focuses on 1D bundles under LLS. As in previous works, a fiber has failure rate following a power law in its load level with breakdown exponent rho. Surviving fibers under fixed loads have remaining lifetimes that are independent and exponentially distributed. We develop both new asymptotic theories and new computational algorithms that greatly increase the bundle sizes that can be treated in large replications (e.g., one million fibers in thousands of realizations). In particular we develop an algorithm that adapts several concepts and methods that are well-known among computer scientists, but relatively unknown among physicists, to dramatically increase the computational speed with no attendant loss of accuracy. We consider various regimes of rho that yield drastically different behavior as N increases. For 1/2< or =rho< or =1, ELS and LLS have remarkably similar behavior (they have identical lifetime distributions at rho=1) with approximate Gaussian bundle lifetime statistics and a

  11. Statistical evaluation of fiber bundle imagery of wavelength multiplexing

    NASA Astrophysics Data System (ADS)

    Zhang, Yixin

    1994-09-01

    The effects of the wavelength multiplexing on the quality of an image transferred through a fiber bundle system is discussed by using the information capacity of an imaging system. The image transfer through a conventional fiber bundle can be thought of as a discrete sampling of the illuminance of the image at the entrance and of the bundle by each fiber element. This discrete sampling limits the band width of signals which can be transmitted. Also, the ends of the component fibers form an obtrusive pattern in the received image. Because, in the dispersion fiber bundle system, each fiber integrates the flux falling upon its entrance aperture, the entire picture format dispersion scan is reproduced at the frequency response characteristic of a uniform disk whose diameter is equal to that of the component fibers. Also, the individual fiber ends are thus blurred out and the obtrusive pattern formed by them is destroyed. It is shown, in theory, that the use of a dispersion method makes it possible to reduce the value of the light transmission nonuniformity contrast and to improve the resolution of fiber bundle image system, respectively.

  12. Dynamic response of fiber bundle under transverse impact.

    SciTech Connect

    Lu, Wei-Yang; Song, Bo

    2010-03-01

    There has been a very high demand in developing efficient soft body armors to protect the military and law enforcement personnel from ballistic or explosive attack. As a basic component in the soft body armor, fibers or fiber bundles play a key role in the performance against ballistic impact. In order to study the ballistic-resistant mechanism of the soft body armor, it is desirable to understand the dynamic response of the fiber bundle under transverse impact. Transverse wave speed is one important parameter because a faster transverse wave speed can make the impact energy dissipate more quickly. In this study, we employed split Hopkinson pressure bar (SHPB) to generate constant high-speed impact on a Kevlar fiber bundle in the transverse direction. The deformation of the fiber bundle was photographed with high-speed digital cameras. The transverse wave speeds were experimentally measured at various transverse impact velocities. The experimental results can also be used to quantitatively verify the current analytical models or to develop new models to describe the dynamic response of fiber bundle under transverse impact.

  13. Geometric Frustration Selects Morphology in Chiral Filament Bundles

    NASA Astrophysics Data System (ADS)

    Hall, Douglas; Bruss, Isaac; Barone, Justin; Grason, Gregory

    Assemblies of twisted filaments appear in a range of biological contexts, from extracellular filament bundles to amyloid fibrils. Owing to numerous distinctions in molecular structures and interactions underlying these diverse assemblies, a framework to predict and classify the basic mechanisms of structure formation in twisted filament assemblies is still lacking. In this study, we model how the size and shape of self-assembled fibers are controlled by competition between the elastic costs of inter-filament frustration, bending deformation of filaments and bundle surface energy. Exploiting a geometric mapping between inter-filament packing in twisted bundles and packing on positively-curved 2D surfaces, we show that the anisotropy of the bundle cross-section is determined by a single parameter describing the competition between elastic and bending costs. We compare the continuum model's predictions for stability of cylindrical and tape-like twisted morphologies to numerical simulations of cohesive filament bundles and observations of micron-scale amyloid fibers assembled from hydrolyzed protein fragments. Nsf (CAREER) DMR-0955760.

  14. Improvements to Wire Bundle Thermal Modeling for Ampacity Determination

    NASA Technical Reports Server (NTRS)

    Rickman, Steve L.; Iannello, Christopher J.; Shariff, Khadijah

    2017-01-01

    Determining current carrying capacity (ampacity) of wire bundles in aerospace vehicles is critical not only to safety but also to efficient design. Published standards provide guidance on determining wire bundle ampacity but offer little flexibility for configurations where wire bundles of mixed gauges and currents are employed with varying external insulation jacket surface properties. Thermal modeling has been employed in an attempt to develop techniques to assist in ampacity determination for these complex configurations. Previous developments allowed analysis of wire bundle configurations but was constrained to configurations comprised of less than 50 elements. Additionally, for vacuum analyses, configurations with very low emittance external jackets suffered from numerical instability in the solution. A new thermal modeler is presented allowing for larger configurations and is not constrained for low bundle infrared emissivity calculations. Formulation of key internal radiation and interface conductance parameters is discussed including the effects of temperature and air pressure on wire to wire thermal conductance. Test cases comparing model-predicted ampacity and that calculated from standards documents are presented.

  15. Consensus Bundle on Maternal Mental Health: Perinatal Depression and Anxiety.

    PubMed

    Kendig, Susan; Keats, John P; Hoffman, M Camille; Kay, Lisa B; Miller, Emily S; Moore Simas, Tiffany A; Frieder, Ariela; Hackley, Barbara; Indman, Pec; Raines, Christena; Semenuk, Kisha; Wisner, Katherine L; Lemieux, Lauren A

    Perinatal mood and anxiety disorders are among the most common mental health conditions encountered by women of reproductive age. When left untreated, perinatal mood and anxiety disorders can have profound adverse effects on women and their children, ranging from increased risk of poor adherence to medical care, exacerbation of medical conditions, loss of interpersonal and financial resources, smoking and substance use, suicide, and infanticide. Perinatal mood and anxiety disorders are associated with increased risks of maternal and infant mortality and morbidity and are recognized as a significant patient safety issue. In 2015, the Council on Patient Safety in Women's Health Care convened an interdisciplinary workgroup to develop an evidence-based patient safety bundle to address maternal mental health. The focus of this bundle is perinatal mood and anxiety disorders. The bundle is modeled after other bundles released by the Council on Patient Safety in Women's Health Care and provides broad direction for incorporating perinatal mood and anxiety disorder screening, intervention, referral, and follow-up into maternity care practice across health care settings. This commentary provides information to assist with bundle implementation.

  16. Consensus Bundle on Maternal Mental Health: Perinatal Depression and Anxiety.

    PubMed

    Kendig, Susan; Keats, John P; Hoffman, M Camille; Kay, Lisa B; Miller, Emily S; Moore Simas, Tiffany A; Frieder, Ariela; Hackley, Barbara; Indman, Pec; Raines, Christena; Semenuk, Kisha; Wisner, Katherine L; Lemieux, Lauren A

    2017-03-01

    Perinatal mood and anxiety disorders are among the most common mental health conditions encountered by women of reproductive age. When left untreated, perinatal mood and anxiety disorders can have profound adverse effects on women and their children, ranging from increased risk of poor adherence to medical care, exacerbation of medical conditions, loss of interpersonal and financial resources, smoking and substance use, suicide, and infanticide. Perinatal mood and anxiety disorders are associated with increased risks of maternal and infant mortality and morbidity and are recognized as a significant patient safety issue. In 2015, the Council on Patient Safety in Women's Health Care convened an interdisciplinary workgroup to develop an evidence-based patient safety bundle to address maternal mental health. The focus of this bundle is perinatal mood and anxiety disorders. The bundle is modeled after other bundles released by the Council on Patient Safety in Women's Health Care and provides broad direction for incorporating perinatal mood and anxiety disorder screening, intervention, referral, and follow-up into maternity care practice across health care settings. This commentary provides information to assist with bundle implementation.

  17. Ecosystem service bundles for analyzing tradeoffs in diverse landscapes.

    PubMed

    Raudsepp-Hearne, C; Peterson, G D; Bennett, E M

    2010-03-16

    A key challenge of ecosystem management is determining how to manage multiple ecosystem services across landscapes. Enhancing important provisioning ecosystem services, such as food and timber, often leads to tradeoffs between regulating and cultural ecosystem services, such as nutrient cycling, flood protection, and tourism. We developed a framework for analyzing the provision of multiple ecosystem services across landscapes and present an empirical demonstration of ecosystem service bundles, sets of services that appear together repeatedly. Ecosystem service bundles were identified by analyzing the spatial patterns of 12 ecosystem services in a mixed-use landscape consisting of 137 municipalities in Quebec, Canada. We identified six types of ecosystem service bundles and were able to link these bundles to areas on the landscape characterized by distinct social-ecological dynamics. Our results show landscape-scale tradeoffs between provisioning and almost all regulating and cultural ecosystem services, and they show that a greater diversity of ecosystem services is positively correlated with the provision of regulating ecosystem services. Ecosystem service-bundle analysis can identify areas on a landscape where ecosystem management has produced exceptionally desirable or undesirable sets of ecosystem services.

  18. A statistical model of protein binding in parallel actin bundles

    NASA Astrophysics Data System (ADS)

    Shin, Homin; Grason, Gregory; Purdy Drew, Kirstin; Wong, Gerard

    2010-03-01

    We propose a coarse-grained lattice model of cross-linking proteins in parallel actin bundles. Based on this model that captures the interplay between geometrical frustration of binding and the intrinsic flexibility of filaments and linkers, we predict a unique regular ground-state structure of fully cross-linked bundles. We also discuss the linker-dependent thermodynamic transition of actin filaments from their native state to the overtwisted state and map out the ``twist-state'' phase diagram in terms of linker flexibility as well as the chemical potential. A flexible linker regime exhibits a continuous spectrum of intermediate twist states, while a stiff linker regime only allows for untwisted actin filaments and fully overtwisted bundles. Our predictions compare well with small-angle scattering studies of bundles formed in the presence of two types of reconstituted cross-linking proteins, fascin and espin. Additionally, this study reveals how subtle differences in crosslinking agents themselves may be used by cells to achieve self-organized bundles with dramatically different properties.

  19. Measuring geometric frustration in twisted inextensible filament bundles

    NASA Astrophysics Data System (ADS)

    Panaitescu, Andreea; Grason, Gregory M.; Kudrolli, Arshad

    2017-05-01

    We investigate with experiments and mapping the structure of a hexagonally ordered filament bundle that is held near its ends and progressively twisted around its central axis. The filaments are free to slide relative to each other and are further held under tension-free boundary conditions. Measuring the bundle packing with micro x-ray imaging, we find that the filaments develop the helical rotation Ω imposed at the boundaries. We then show that the observed structure is consistent with a mapping of the filament positions to disks packed on a dual non-Euclidean surface with a Gaussian curvature which increases with twist. We further demonstrate that the mean interfilament distance is minimal on the surface, which can be approximated by a hemisphere with an effective curvature Keff=3 Ω2 . Examining the packing on the dual surface, we analyze the geometric frustration of packing in twisted bundles and find the core to remain relatively hexagonally ordered with interfilament strains growing from the bundle center, driving the formation of defects at the exterior of highly twisted bundles.

  20. Variable recruitment in bundles of miniature pneumatic artificial muscles.

    PubMed

    DeLaHunt, Sylvie A; Pillsbury, Thomas E; Wereley, Norman M

    2016-09-13

    The natural compliance and force generation properties of pneumatic artificial muscles (PAMs) allow them to operate like human muscles in anthropomorphic robotic manipulators. Traditionally, manipulators use a single PAM or multiple PAMs actuated in unison in place of a human muscle. However, these standard manipulators can experience significant efficiency losses when operated outside their target performance ranges at low actuation pressures. This study considers the application of a variable recruitment control strategy to a parallel bundle of miniature PAMs as an attempt to mimic the selective recruitment of motor units in a human muscle. Bundles of miniature PAMs are experimentally characterized, their actuation behavior is modeled, and the efficiency gains and losses associated with the application of a variable recruitment control strategy are assessed. This bio-inspired control strategy allows muscle bundles to operate the fewest miniature PAMs necessary to achieve a desired performance objective, improving the muscle bundle's operating efficiency over larger ranges of force generation and displacement. The study also highlights the need for improved PAM fabrication techniques to facilitate the production of identical miniature PAMs for inclusion in muscle bundles.

  1. Hair-bundle friction from transduction channels' gating forces

    NASA Astrophysics Data System (ADS)

    Bormuth, Volker; Barral, Jérémie; Joanny, Jean-François; Jülicher, Frank; Martin, Pascal

    2015-12-01

    Hearing starts when sound-evoked mechanical vibrations of the hair-cell bundle activate mechanosensitive ion channels, giving birth to an electrical signal. As for any mechanical system, friction impedes movements of the hair bundle and thus constrains the sensitivity and frequency selectivity of auditory transduction. We have shown recently that the opening and closing of the transduction channels produce internal frictional forces that can dominate viscous drag on the micrometer-sized hair bundle and thus provide a major source of damping [2]. We develop here a physical theory of passive hair-bundle mechanics that explains the origin of channel friction. We show that channel friction can be understood quantitatively by coupling the dynamics of the conformational change associated with channel gating to tip-link tension. As a result, varying channel properties affects friction, with faster channels producing smaller friction. The analysis emphasizes the dual role of transduction channels' gating forces, which affect both hair-bundle stiffness and drag. Friction originating from gating of ion channels is a general concept that is relevant to all mechanosensitive channels.

  2. Consensus Bundle on Maternal Mental Health: Perinatal Depression and Anxiety.

    PubMed

    Kendig, Susan; Keats, John P; Hoffman, M Camille; Kay, Lisa B; Miller, Emily S; Simas, Tiffany A Moore; Frieder, Ariela; Hackley, Barbara; Indman, Pec; Raines, Christena; Semenuk, Kisha; Wisner, Katherine L; Lemieux, Lauren A

    2017-03-01

    Perinatal mood and anxiety disorders are among the most common mental health conditions encountered by women of reproductive age. When left untreated, perinatal mood and anxiety disorders can have profound adverse effects on women and their children, ranging from increased risk of poor adherence to medical care, exacerbation of medical conditions, loss of interpersonal and financial resources, smoking and substance use, suicide, and infanticide. Perinatal mood and anxiety disorders are associated with increased risks of maternal and infant mortality and morbidity and are recognized as a significant patient safety issue. In 2015, the Council on Patient Safety in Women's Health Care convened an interdisciplinary work group to develop an evidence-based patient safety bundle to address maternal mental health. The focus of this bundle is perinatal mood and anxiety disorders. The bundle is modeled after other bundles released by the Council on Patient Safety in Women's Health Care and provides broad direction for incorporating perinatal mood and anxiety disorder screening, intervention, referral, and follow-up into maternity care practice across health care settings. This commentary provides information to assist with bundle implementation. © 2017 by the American College of Nurse-Midwives.

  3. Surgical Management of Neurovascular Bundle in Uterine Fibroid Pseudocapsule

    PubMed Central

    Malvasi, Antonio; Hurst, Brad S.; Tsin, Daniel A.; Davila, Fausto; Dominguez, Guillermo; Dell'edera, Domenico; Cavallotti, Carlo; Negro, Roberto; Gustapane, Sarah; Teigland, Chris M.; Mettler, Liselotte

    2012-01-01

    The uterine fibroid pseudocapsule is a fibro-neurovascular structure surrounding a leiomyoma, separating it from normal peripheral myometrium. The fibroid pseudocapsule is composed of a neurovascular network rich in neurofibers similar to the neurovascular bundle surrounding a prostate. The nerve-sparing radical prostatectomy has several intriguing parallels to myomectomy. It may serve either as a useful model in modern fibroid surgical removal, or it may accelerate our understanding of the role of the fibrovascular bundle and neurotransmitters in the healing and restoration of reproductive potential after intracapsular myomectomy. Surgical innovations, such as laparoscopic or robotic myomectomy applied to the intracapsular technique with magnification of the fibroid pseudocapsule surrounding a leiomyoma, originated from the radical prostatectomy method that highlighted a careful dissection of the neurovascular bundle to preserve sexual functioning after prostatectomy. Gentle uterine leiomyoma detachment from the pseudocapsule neurovascular bundle has allowed a reduction in uterine bleeding and uterine musculature trauma with sparing of the pseudocapsule neuropeptide fibers. This technique has had a favorable impact on functionality in reproduction and has improved fertility outcomes. Further research should determine the role of the myoma pseudocapsule neurovascular bundle in the formation, growth, and pathophysiological consequences of fibroids, including pain, infertility, and reproductive outcomes. PMID:22906340

  4. Abnormal cingulum bundle development in autism: a probabilistic tractography study.

    PubMed

    Ikuta, Toshikazu; Shafritz, Keith M; Bregman, Joel; Peters, Bart D; Gruner, Patricia; Malhotra, Anil K; Szeszko, Philip R

    2014-01-30

    There is now considerable evidence that white matter abnormalities play a role in the neurobiology of autism. Little research has been directed, however, at understanding (a) typical white matter development in autism and how this relates to neurocognitive impairments observed in the disorder. In this study we used probabilistic tractography to identify the cingulum bundle in 21 adolescents and young adults with Autism Spectrum Disorder (ASD), and 21 age- and sex-matched healthy volunteers. We investigated group differences in the relationships between age and fractional anisotropy, a putative measure of white matter integrity, within the cingulum bundle. Moreover, in a preliminary investigation, we examined the relationship between cingulum fractional anisotropy and executive functioning using the Behavior Rating Inventory of Executive Function (BRIEF). The ASD participants demonstrated significantly lower fractional anisotropy within the cingulum bundle compared to the typically developing volunteers. There was a significant group-by-age interaction such that the ASD group did not show the typical age-associated increases in fractional anisotropy observed among healthy individuals. Moreover, lower fractional anisotropy within the cingulum bundle was associated with worse BRIEF behavioral regulation index scores in the ASD group. The current findings implicate a dysregulation in cingulum bundle white matter development occurring in late adolescence and early adulthood in ASD, and suggest that greater disturbances in this trajectory are associated with executive dysfunction in ASD.

  5. Ecosystem service bundles for analyzing tradeoffs in diverse landscapes

    PubMed Central

    Raudsepp-Hearne, C.; Peterson, G. D.; Bennett, E. M.

    2010-01-01

    A key challenge of ecosystem management is determining how to manage multiple ecosystem services across landscapes. Enhancing important provisioning ecosystem services, such as food and timber, often leads to tradeoffs between regulating and cultural ecosystem services, such as nutrient cycling, flood protection, and tourism. We developed a framework for analyzing the provision of multiple ecosystem services across landscapes and present an empirical demonstration of ecosystem service bundles, sets of services that appear together repeatedly. Ecosystem service bundles were identified by analyzing the spatial patterns of 12 ecosystem services in a mixed-use landscape consisting of 137 municipalities in Quebec, Canada. We identified six types of ecosystem service bundles and were able to link these bundles to areas on the landscape characterized by distinct social–ecological dynamics. Our results show landscape-scale tradeoffs between provisioning and almost all regulating and cultural ecosystem services, and they show that a greater diversity of ecosystem services is positively correlated with the provision of regulating ecosystem services. Ecosystem service-bundle analysis can identify areas on a landscape where ecosystem management has produced exceptionally desirable or undesirable sets of ecosystem services. PMID:20194739

  6. [The double ventricular response phenomenon in 2 cases of Wolff-Parkinson-White syndrome].

    PubMed

    Guize, L; Meilhac, B; Cabanis, C; Di Mattéo, J; Maurice, P

    1978-02-01

    The authors report two cases of "true" consecutive double ventricular response caused by a single premature atrial stimulation; both were young men with Wolff-Parkinson-White syndrome. In both cases, the presence of a bundle of Kent was confirmed. The phenomenon of double ventricular response arising successively from the bundle of Kent and node-His pathway is rare, being mentioned in only two cases in the literature. It is only found when there is the combination of a good bundle of Kent, fair forward conduction, and a relative ventricle-His retrograde block. Amongst the other mechanisms for double ventricular repsonse, re-entry from branch to branch presents the most difficult differential diagnosis. From our observations, the forward characteristics of the spread through the bundle of His which always procedes the bundle of His which always precedes the second ventricular complex have been confirmed, especially in view of the freat variation in the position of this potential which can easily be explained by variations in intra-nodal conduction. In one of these cases, the atriogram, taken after the second ventriculogram, was provided by retrograde activity in the bundle of Kent.

  7. The Role of Fibers in the Femoral Attachment of the Anterior Cruciate Ligament in Resisting Tibial Displacement

    PubMed Central

    Kawaguchi, Yasuyuki; Kondo, Eiji; Takeda, Ryo; Akita, Keiichi; Yasuda, Kazunori; Amis, Andrew A.

    2015-01-01

    Purpose The purpose was to clarify the load-bearing functions of the fibers of the femoral anterior cruciate ligament (ACL) attachment in resisting tibial anterior drawer and rotation. Methods A sequential cutting study was performed on 8 fresh-frozen human knees. The femoral attachment of the ACL was divided into a central area that had dense fibers inserting directly into the femur and anterior and posterior fan-like extension areas. The ACL fibers were cut sequentially from the bone: the posterior fan-like area in 2 stages, the central dense area in 4 stages, and then the anterior fan-like area in 2 stages. Each knee was mounted in a robotic joint testing system that applied tibial anteroposterior 6-mm translations and 10° or 15° of internal rotation at 0° to 90° of flexion. The reduction of restraining force or moment was measured after each cut. Results The central area resisted 82% to 90% of the anterior drawer force; the anterior fan-like area, 2% to 3%; and the posterior fan-like area, 11% to 15%. Among the 4 central areas, most load was carried close to the roof of the intercondylar notch: the anteromedial bundle resisted 66% to 84% of the force and the posterolateral bundle resisted 16% to 9% from 0° to 90° of flexion. There was no clear pattern for tibial internal rotation, with the load shared among the posterodistal and central areas near extension and mostly the central areas in flexion. Conclusions Under the experimental conditions described, 66% to 84% of the resistance to tibial anterior drawer arose from the ACL fibers at the central-proximal area of the femoral attachment, corresponding to the anteromedial bundle; the fan-like extension fibers contributed very little. This work did not support moving a single-bundle ACL graft to the side wall of the notch or attempting to cover the whole attachment area if the intention was to mimic how the natural ACL resists tibial displacements. Clinical Relevance There is ongoing debate about how best

  8. High thermodynamic stability of parametrically designed helical bundles

    SciTech Connect

    Huang, Po -Ssu; Oberdorfer, Gustav; Xu, Chunfu; Pei, Xue Y.; Nannenga, Brent L.; Rogers, Joseph M.; DiMaio, Frank; Gonen, Tamir; Luisi, Ben; Baker, David

    2014-10-24

    Here we describe a procedure for designing proteins with backbones produced by varying the parameters in the Crick coiled coil–generating equations. Combinatorial design calculations identify low-energy sequences for alternative helix supercoil arrangements, and the helices in the lowest-energy arrangements are connected by loop building. We design an antiparallel monomeric untwisted three-helix bundle with 80-residue helices, an antiparallel monomeric right-handed four-helix bundle, and a pentameric parallel left-handed five-helix bundle. The designed proteins are extremely stable (extrapolated ΔGfold > 60 kilocalories per mole), and their crystal structures are close to those of the design models with nearly identical core packing between the helices. The approach enables the custom design of hyperstable proteins with fine-tuned geometries for a wide range of applications.

  9. Betti numbers of graded modules and cohomology of vector bundles

    NASA Astrophysics Data System (ADS)

    Eisenbud, David; Schreyer, Frank-Olaf

    2009-07-01

    In the remarkable paper Graded Betti numbers of Cohen-Macaulay modules and the multiplicity conjecture, Mats Boij and Jonas Soederberg conjectured that the Betti table of a Cohen-Macaulay module over a polynomial ring is a positive linear combination of Betti tables of modules with pure resolutions. We prove a strengthened form of their conjectures. Applications include a proof of the Multiplicity Conjecture of Huneke and Srinivasan and a proof of the convexity of a fan naturally associated to the Young lattice. With the same tools we show that the cohomology table of any vector bundle on projective space is a positive rational linear combination of the cohomology tables of what we call supernatural vector bundles. Using this result we give new bounds on the slope of a vector bundle in terms of its cohomology.

  10. System for supporting bundled tube segments within a combustor

    DOEpatents

    Melton, Patrick Benedict

    2016-03-01

    A system for supporting bundled tube segments within a combustor includes an annular sleeve that extends circumferentially and axially within the combustor, a support lug that extends radially inward from the annular sleeve and an annular support frame that is disposed within the annular sleeve. The annular support frame includes an inner ring portion, an outer ring portion and a plurality of spokes that extend radially between the inner and outer ring portions. The inner ring portion, the outer ring portion and the plurality of spokes define an annular array of openings for receiving a respective bundled tube segment. The inner ring portion is connected to each bundled tube segment and the outer ring portion is coupled to the support lug.

  11. High-order synchronization of hair cell bundles

    NASA Astrophysics Data System (ADS)

    Levy, Michael; Molzon, Adrian; Lee, Jae-Hyun; Kim, Ji-Wook; Cheon, Jinwoo; Bozovic, Dolores

    2016-12-01

    Auditory and vestibular hair cell bundles exhibit active mechanical oscillations at natural frequencies that are typically lower than the detection range of the corresponding end organs. We explore how these noisy nonlinear oscillators mode-lock to frequencies higher than their internal clocks. A nanomagnetic technique is used to stimulate the bundles without an imposed mechanical load. The evoked response shows regimes of high-order mode-locking. Exploring a broad range of stimulus frequencies and intensities, we observe regions of high-order synchronization, analogous to Arnold Tongues in dynamical systems literature. Significant areas of overlap occur between synchronization regimes, with the bundle intermittently flickering between different winding numbers. We demonstrate how an ensemble of these noisy spontaneous oscillators could be entrained to efficiently detect signals significantly above the characteristic frequencies of the individual cells.

  12. Magnetic Propulsion of Microswimmers with DNA-Based Flagellar Bundles

    PubMed Central

    2016-01-01

    We show that DNA-based self-assembly can serve as a general and flexible tool to construct artificial flagella of several micrometers in length and only tens of nanometers in diameter. By attaching the DNA flagella to biocompatible magnetic microparticles, we provide a proof of concept demonstration of hybrid structures that, when rotated in an external magnetic field, propel by means of a flagellar bundle, similar to self-propelling peritrichous bacteria. Our theoretical analysis predicts that flagellar bundles that possess a length-dependent bending stiffness should exhibit a superior swimming speed compared to swimmers with a single appendage. The DNA self-assembly method permits the realization of these improved flagellar bundles in good agreement with our quantitative model. DNA flagella with well-controlled shape could fundamentally increase the functionality of fully biocompatible nanorobots and extend the scope and complexity of active materials. PMID:26821214

  13. Rheology of semiflexible bundle networks with transient linkers.

    PubMed

    Müller, Kei W; Bruinsma, Robijn F; Lieleg, Oliver; Bausch, Andreas R; Wall, Wolfgang A; Levine, Alex J

    2014-06-13

    We present a theoretical and computational analysis of the rheology of networks made up of bundles of semiflexible filaments bound by transient cross-linkers. Such systems are ubiquitous in the cytoskeleton and can be formed in vitro using filamentous actin and various cross-linkers. We find that their high-frequency rheology is characterized by a scaling behavior that is quite distinct from that of networks of the well-studied single semiflexible filaments. This regime can be understood theoretically in terms of a length-scale-dependent bending modulus for bundles. Next, we observe new dissipative dynamics associated with the shear-induced disruption of the network at intermediate frequencies. Finally, at low frequencies, we encounter a region of non-Newtonian rheology characterized by power-law scaling. This regime is dominated by bundle dissolution and large-scale rearrangements of the network driven by equilibrium thermal fluctuations.

  14. High-order synchronization of hair cell bundles

    PubMed Central

    Levy, Michael; Molzon, Adrian; Lee, Jae-Hyun; Kim, Ji-wook; Cheon, Jinwoo; Bozovic, Dolores

    2016-01-01

    Auditory and vestibular hair cell bundles exhibit active mechanical oscillations at natural frequencies that are typically lower than the detection range of the corresponding end organs. We explore how these noisy nonlinear oscillators mode-lock to frequencies higher than their internal clocks. A nanomagnetic technique is used to stimulate the bundles without an imposed mechanical load. The evoked response shows regimes of high-order mode-locking. Exploring a broad range of stimulus frequencies and intensities, we observe regions of high-order synchronization, analogous to Arnold Tongues in dynamical systems literature. Significant areas of overlap occur between synchronization regimes, with the bundle intermittently flickering between different winding numbers. We demonstrate how an ensemble of these noisy spontaneous oscillators could be entrained to efficiently detect signals significantly above the characteristic frequencies of the individual cells. PMID:27974743

  15. High thermodynamic stability of parametrically designed helical bundles

    DOE PAGES

    Huang, Po -Ssu; Oberdorfer, Gustav; Xu, Chunfu; ...

    2014-10-24

    Here we describe a procedure for designing proteins with backbones produced by varying the parameters in the Crick coiled coil–generating equations. Combinatorial design calculations identify low-energy sequences for alternative helix supercoil arrangements, and the helices in the lowest-energy arrangements are connected by loop building. We design an antiparallel monomeric untwisted three-helix bundle with 80-residue helices, an antiparallel monomeric right-handed four-helix bundle, and a pentameric parallel left-handed five-helix bundle. The designed proteins are extremely stable (extrapolated ΔGfold > 60 kilocalories per mole), and their crystal structures are close to those of the design models with nearly identical core packing between themore » helices. The approach enables the custom design of hyperstable proteins with fine-tuned geometries for a wide range of applications.« less

  16. IKKε inhibits PKC to promote Fascin-dependent actin bundling

    PubMed Central

    Ogura, Yosuke; Misaki, Kazuyo; Maeda, Takuya; Kimpara, Akiyo; Yonemura, Shigenobu; Hayashi, Shigeo

    2016-01-01

    Signaling molecules have pleiotropic functions and are activated by various extracellular stimuli. Protein kinase C (PKC) is activated by diverse receptors, and its dysregulation is associated with diseases including cancer. However, how the undesired activation of PKC is prevented during development remains poorly understood. We have previously shown that a protein kinase, IKKε, is active at the growing bristle tip and regulates actin bundle organization during Drosophila bristle morphogenesis. Here, we demonstrate that IKKε regulates the actin bundle localization of a dynamic actin cross-linker, Fascin. IKKε inhibits PKC, thereby protecting Fascin from inhibitory phosphorylation. Excess PKC activation is responsible for the actin bundle defects in IKKε-deficient bristles, whereas PKC is dispensable for bristle morphogenesis in wild-type bristles, indicating that PKC is repressed by IKKε in wild-type bristle cells. These results suggest that IKKε prevents excess activation of PKC during bristle morphogenesis. PMID:27578797

  17. Muon Bundles as a Sign of Strangelets from the Universe

    NASA Astrophysics Data System (ADS)

    Kankiewicz, P.; Rybczyński, M.; Włodarczyk, Z.; Wilk, G.

    2017-04-01

    Recently, the CERN ALICE experiment observed muon bundles of very high multiplicities in its dedicated cosmic ray (CR) run, thereby confirming similar findings from the LEP era at CERN (in the CosmoLEP project). Originally, it was argued that they apparently stem from the primary CRs with a heavy masses. We propose an alternative possibility arguing that muonic bundles of highest multiplicity are produced by strangelets, hypothetical stable lumps of strange quark matter infiltrating our universe. We also address the possibility of additionally deducing their directionality which could be of astrophysical interest. Significant evidence for anisotropy of arrival directions of the observed high-multiplicity muonic bundles is found. Estimated directionality suggests their possible extragalactic provenance.

  18. Magnetic Propulsion of Microswimmers with DNA-Based Flagellar Bundles.

    PubMed

    Maier, Alexander M; Weig, Cornelius; Oswald, Peter; Frey, Erwin; Fischer, Peer; Liedl, Tim

    2016-02-10

    We show that DNA-based self-assembly can serve as a general and flexible tool to construct artificial flagella of several micrometers in length and only tens of nanometers in diameter. By attaching the DNA flagella to biocompatible magnetic microparticles, we provide a proof of concept demonstration of hybrid structures that, when rotated in an external magnetic field, propel by means of a flagellar bundle, similar to self-propelling peritrichous bacteria. Our theoretical analysis predicts that flagellar bundles that possess a length-dependent bending stiffness should exhibit a superior swimming speed compared to swimmers with a single appendage. The DNA self-assembly method permits the realization of these improved flagellar bundles in good agreement with our quantitative model. DNA flagella with well-controlled shape could fundamentally increase the functionality of fully biocompatible nanorobots and extend the scope and complexity of active materials.

  19. Stable parabolic Higgs bundles as asymptotically stable decorated swamps

    NASA Astrophysics Data System (ADS)

    Beck, Nikolai

    2016-06-01

    Parabolic Higgs bundles can be described in terms of decorated swamps, which we studied in a recent paper. This description induces a notion of stability of parabolic Higgs bundles depending on a parameter, and we construct their moduli space inside the moduli space of decorated swamps. We then introduce asymptotic stability of decorated swamps in order to study the behaviour of the stability condition as one parameter approaches infinity. The main result is the existence of a constant, such that stability with respect to parameters greater than this constant is equivalent to asymptotic stability. This implies boundedness of all decorated swamps which are semistable with respect to some parameter. Finally, we recover the usual stability condition of parabolic Higgs bundles as asymptotic stability.

  20. Packing defects and the width of biopolymer bundles.

    PubMed

    Gov, Nir S

    2008-07-01

    The formation of bundles composed of actin filaments and cross-linking proteins is an essential process in the maintenance of the cells' cytoskeleton. It has also been recreated by in-vitro experiments, where actin networks are routinely produced to mimic and study the cellular structures. It has been observed that these bundles seem to have a well-defined width distribution, which has not been adequately described theoretically. We propose here that packing defects of the filaments, quenched and random, contribute an effective repulsion that counters the cross-linking adhesion energy and leads to a well-defined bundle width. This is a two-dimensional strain-field version of the classic Rayleigh instability of charged droplets.

  1. Preparation of superhydrophobic poly-p-phenylenebenzobisoxazole (PBO) fiber bundles

    NASA Astrophysics Data System (ADS)

    Jiang, Zai X.; Geng, Lin; Huang, Yu D.

    2011-02-01

    According to the reformed Cassie-Baxter equation, the superhydrophobic phenylenebenzobisoxazole (PBO) fiber bundle boats were fabricated from mimicking the lotus leaf venation using chemical surface modifications and roughness introduction. Water contact angles as high as 152.3° were achieved for PBO fiber bundles. Furthermore, the loading capacities of the superhydrophobic PBO fiber bundle boats were also measured. And the highest loading weight, 8.36 g, was obtained by the boats treated with 2.0 wt.% (heptadecafluoro-1,1,2,2,-tetradecyl)trimethoxysilane (HFTES). The large loading capacities were believed to arise from the air film surrounding the superhydrophobic surfaces of boats. The results of this study presented new applications of artificial hydrophobic surfaces in areas of miniature aquatic devices.

  2. Assessment of anterolateral rotatory instability in the anterior cruciate ligament-deficient knee using an open magnetic resonance imaging system.

    PubMed

    Okazaki, Ken; Miura, Hiromasa; Matsuda, Shuich; Yasunaga, Takefumi; Nakashima, Hideaki; Konishi, Kozo; Iwamoto, Yukihide; Hashizume, Makoto

    2007-07-01

    In the clinical evaluation of the anterior cruciate ligament-deficient knee, anterolateral rotatory instability is assessed by manual tests such as the pivot-shift test, which is subjective and not quantitative. The anterolateral rotatory instability in an anterior cruciate ligament-deficient knee can be quantified by our newly developed method using open magnetic resonance imaging. Controlled laboratory study. Eighteen subjects with anterior cruciate ligament-deficient knees and 18 with normal knees were recruited. We administered the Slocum anterolateral rotatory instability test in the open magnetic resonance imaging scanner and scanned the sagittal view of the knee. The anterior displacements of the tibia at the medial and lateral compartments were measured. Furthermore, we examined 14 anterior cruciate ligament-deficient knees twice to assess intraobserver and interobserver reproducibility and evaluated the difference and interclass correlation coefficient of 2 measures. In the anterior cruciate ligament-deficient knee, displacement was 14.4 +/- 5.5 mm at the lateral compartment and 1.6 +/- 2.3 mm at the medial compartment; in the normal knee, displacement was 0.7 +/- 1.9 mm and -1.1 +/- 1.2 mm, respectively. The difference and interclass correlation coefficient between 2 repeated measures at the lateral compartment were 1.0 +/- 0.7 mm and .98 for intraobserver reproducibility and 1.1 +/- 0.7 mm and .91 for interobserver reproducibility. This method is useful to assess the anterolateral rotatory instability of the anterior cruciate ligament-deficient knee. This method can be used in the clinical assessment of anterior cruciate ligament stability, such as comparing studies of graft positions or 2-bundle anatomic reconstruction and the conventional 1-bundle technique.

  3. Fiber bundle design for an integrated wearable artificial lung.

    PubMed

    Madhani, Shalv P; Frankowski, Brian J; Federspiel, William J

    2017-02-07

    Mechanical ventilation and ECMO are the only viable treatment options for lung failure patients at the end stage, including ARDS and COPD. These treatments however are associated with high morbidity and mortality due to long wait times for lung transplant. Contemporary clinical literature has shown ambulation improves post-transplant outcomes in lung failure patients. Given this, we are developing the PAAL, a truly wearable artificial lung that allows for ambulation. In this study, we targeted 180 ml/min oxygenation and determined the form factor for a hollow fiber membrane (HFM) bundle for the PAAL.Based on a previously published mass transfer correlation we modeled oxygenation efficiency as a function of fiber bundle diameter. Three benchmark fiber bundles were fabricated to validate the model through in-vitro blood gas exchange at blood flow rates from 1 to 4 L/min according to ASTM standards. We used the model to determine a final design, which was characterized in-vitro through a gas exchange as well as a hemolysis study at 3.5 L/minThe percent difference between model predictions and experiment for the benchmark bundles ranged from 3% to 17.5% at the flowrates tested. Using the model, we predicted a 1.75 inch diameter bundle with 0.65 m surface area would produce 180 ml/min at 3.5 L/min blood flow rate. The oxygenation efficiency was 278 ml/min/m and the Normalized Index of Hemolysis (NIH) was less than 0.05g/100L. Future work involves integrating this bundle into the PAAL for which an experimental prototype is under development in our laboratory.

  4. Reorganization of actin filament bundles in living fibroblasts

    PubMed Central

    1984-01-01

    We investigated how actin bundles assemble, disassemble, and reorganize during cell movement. Living chick embryonic fibroblasts were microinjected with actin molecules that had been fluorescently labeled with tetramethylrhodamine. We found that the fluorescent analogue of actin can be used successfully by both existing and newly formed cellular structures. Using time-lapse photography coupled to image- intensified fluorescence microscopy, we were able to detect various patterns of reorganization in motile cells. Assembly of stress fibers occurred near both the leading and the trailing ends of the cell. The initial structure appeared as discrete spots that subsequently extended into stress fibers. The extension occurred unidirectionally. The site of initiation near the leading edge remained stationary relative to the substrate during subsequent cell advancement. However, the orientation of the fiber could change according to the direction of cell movement. In addition, existing stress fibers could merge or fragment. The shortening of stress fibers can occur from either end of the fiber. Shortening from the proximal end (centrifugal shortening) was accompanied by a decrease in fluorescence intensity, as if the bundle were disassembling, and usually led to the total disappearance of the bundle. Shortening from the distal end (centripetal shortening), on the other hand, is usually accompanied by an increase in fluorescence intensity at the distal end of the bundle, as if this end had pulled loose from its attachment and retracted toward the center of the cell. Besides stress fibers, arc-like actin bundles have also been detected in spreading cells. These observations can explain how the organization of actin bundles coordinates with cell movement, and how stress fibers reach a highly regular pattern in static cells. PMID:6541223

  5. Dunkl Operators as Covariant Derivatives in a Quantum Principal Bundle

    NASA Astrophysics Data System (ADS)

    Durdevich, Micho; Sontz, Stephen Bruce

    2013-05-01

    A quantum principal bundle is constructed for every Coxeter group acting on a finite-dimensional Euclidean space E, and then a connection is also defined on this bundle. The covariant derivatives associated to this connection are the Dunkl operators, originally introduced as part of a program to generalize harmonic analysis in Euclidean spaces. This gives us a new, geometric way of viewing the Dunkl operators. In particular, we present a new proof of the commutativity of these operators among themselves as a consequence of a geometric property, namely, that the connection has curvature zero.

  6. Capture and manipulation of hybrid DNAs by carbon nanotube bundles.

    PubMed

    Li, Zhenhai; Yang, Wei

    2010-05-14

    When approached from both sides, a piece of single-duplex-single DNA may be drawn into the inlets of two bundles of carbon nanotubes. This provides opportunities to manipulate the DNA by two bundles of nanotubes. The capture and manipulation processes envisaged above are simulated by molecular dynamics in this work. The radius of the carbon nanotube and the ambient temperature show the effects on the spontaneous insertion of DNA strands. This procedure, if successful, could be used for capturing expectant sdsDNAs, with subsequent manipulation to pull or to unzip the captured DNA.

  7. One-sided ejaculation of echidna sperm bundles.

    PubMed

    Johnston, S D; Smith, B; Pyne, M; Stenzel, D; Holt, W V

    2007-12-01

    We report for the first time an unusual ejaculatory mechanism in the short-beaked echidna in which each side of the bilaterally symmetrical, rosettelike glans penis is used alternately, with the other being shut down. This is unparalleled in mammals but is reminiscent of the use of hemipenes in squamate reptiles, providing further reproductive evidence of a sauropsidian lineage in the Monotremata. Further, we describe the occurrence of motile sperm bundles in ejaculated echidna semen and provide scanning electron micrographs of their morphology. Sperm bundling appears to confer increased sperm motility, which may provide the potential for sperm competition between males.

  8. Phase Transition to Bundles of Flexible Supramolecular Polymers

    NASA Astrophysics Data System (ADS)

    Huisman, B. A. H.; Bolhuis, P. G.; Fasolino, A.

    2008-05-01

    We report Monte Carlo simulations of the self-assembly of supramolecular polymers based on a model of patchy particles. We find a first-order phase transition, characterized by hysteresis and nucleation, toward a solid bundle of polymers, of length much greater than the average gas phase length. We argue that the bundling transition is the supramolecular equivalent of the sublimation transition, which results from a weak chain-chain interaction. We provide a qualitative equation of state that gives physical insight beyond the specific values of the parameters used in our simulations.

  9. Chern-Simons functional under gauge transformations on flat bundles

    NASA Astrophysics Data System (ADS)

    Byun, Yanghyun; Kim, Joohee

    2017-01-01

    We describe the effect of a gauge transformation on the Chern-Simons functional in a thorough and unifying manner. We use the assumptions that the structure group is compact and connected and, in particular, that the principal bundle is flat. The Chern-Simons functional we consider is the one defined by choosing a flat reference connection. The most critical step in arriving at the main result is to show both the existence and the uniqueness of a cohomology class on the adjoint bundle such that it is the class of the so-called Maurer-Cartan 3-form when restricted to each fiber.

  10. On Some Transverse Geometrical Structures of Lifted Foliation to Its Conormal Bundle

    PubMed Central

    Ida, Cristian; Oană, Alexandru

    2015-01-01

    We consider the lift of a foliation to its conormal bundle and some transverse geometrical structures associated with this foliation are studied. We introduce a good vertical connection on the conormal bundle and, moreover, if the conormal bundle is endowed with a transversal Cartan metric, we obtain that the lifted foliation to its conormal bundle is a Riemannian one. Also, some transversally framed f(3, ε)-structures of corank 2 on the normal bundle of lifted foliation to its conormal bundle are introduced and an almost (para)contact structure on a transverse Liouville distribution is obtained. PMID:25834835

  11. In vivo posterior cruciate ligament elongation in running activity after anatomic and non-anatomic anterior cruciate ligament reconstruction.

    PubMed

    Tang, Jing; Thorhauer, Eric; Bowman, Karl; Fu, Freddie H; Tashman, Scott

    2017-04-01

    The goals of this study were to (1) investigate the in vivo elongation behaviour of the posterior cruciate ligament (PCL) during running in the uninjured knee and (2) evaluate changes in PCL elongation during running after anatomic or non-anatomic anterior cruciate ligament (ACL) reconstruction. Seventeen unilateral ACL-injured subjects were recruited after undergoing anatomic (n = 9) or non-anatomic (n = 8) ACL reconstruction. Bilateral high-resolution CT scans were obtained to produce 3D models. Anterolateral (AL) and posteromedial (PM) bundles insertion sites of the PCL were identified on the 3D CT scan reconstructions. Dynamic knee function was assessed during running using a dynamic stereo X-ray (DSX) system. The lengths of the AL and PM bundles were estimated from late swing through mid-stance. The contralateral knees served as normal controls. Control knees demonstrated a slight decrease in AL bundle and a significant decrease in PM bundle length following foot strike. Length and elongation patterns of the both bundles of the PCL in the anatomic ACL reconstruction group were similar to the controls. However, the change in dynamic PCL length was significantly greater in the non-anatomic group than in the anatomic reconstruction group after foot strike (p < 0.05). The AL bundle length decreased slightly, and the PM bundle length significantly decreased after foot strike during running in uninjured knees. Anatomic ACL reconstruction maintained normal PCL elongation patterns more effectively than non-anatomic ACL reconstruction during high-demand, functional loading. These results support the use of anatomic ACL reconstruction to achieve normal knee function in high-demand activities. Case-control study, Level III.

  12. Are accessory hearing structures linked to inner ear morphology? Insights from 3D orientation patterns of ciliary bundles in three cichlid species

    PubMed Central

    2014-01-01

    Background Cichlid fishes show considerable diversity in swim bladder morphology. In members of the subfamily Etroplinae, the connection between anterior swim bladder extensions and the inner ears enhances sound transmission and translates into an improved hearing ability. We tested the hypothesis that those swim bladder modifications coincide with differences in inner ear morphology and thus compared Steatocranus tinanti (vestigial swim bladder), Hemichromis guttatus (large swim bladder without extensions), and Etroplus maculatus (intimate connection between swim bladder and inner ears). Methodology and results We applied immunostaining together with confocal imaging and scanning electron microscopy for the investigation of sensory epithelia, and high-resolution, contrast-enhanced microCT imaging for characterizing inner ears in 3D, and evaluated otolith dimensions. Compared to S. tinanti and H. guttatus, inner ears of E. maculatus showed an enlargement of all three maculae, and a particularly large lacinia of the macula utriculi. While our analysis of orientation patterns of ciliary bundles on the three macula types using artificially flattened maculae uncovered rather similar orientation patterns of ciliary bundles, interspecific differences became apparent when illustrating the orientation patterns on the 3D models of the maculae: differences in the shape and curvature of the lacinia of the macula utriculi, and the anterior arm of the macula lagenae resulted in an altered arrangement of ciliary bundles. Conclusions Our results imply that improved audition in E. maculatus is associated not only with swim bladder modifications but also with altered inner ear morphology. However, not all modifications in E. maculatus could be connected to enhanced auditory abilities, and so a potential improvement of the vestibular sense, among others, also needs to be considered. Our study highlights the value of analyzing orientation patterns of ciliary bundles in their intact 3

  13. 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)

  14. 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)

  15. Defect-driven shape instabilities in cohesive filament bundles

    NASA Astrophysics Data System (ADS)

    Bruss, Isaac; Grason, Gregory

    When defects are incorporated into the lattice of a flexible 2D crystalline membrane, it buckles into a new configuration. Specifically, 5- and 7-fold disclinations produce conical- and saddle-like geometries respectively. For bundles composed of a crystalline array of cohesive flexible filaments, we propose a similar phenomena of defect-induced buckling. This revelation is fueled by a recently discovered mapping between the metric properties of a curved surface, and the inter-filament spacing within a deformed bundle. Using a combination of continuum elasticity theory and numerical simulations, we investigate the effects of defects in the cross section on a bundle's global structure. We find that positive disclinations promote the twisting of filaments around a central axis within the bundle, while negative disclinations promote twisting around two parallel axes simultaneously. Both instabilities are interpreted by means of their equivalent Gaussian curvature, and map appropriately to the the corresponding membrane responses. Additionally, for 5-fold disclinations we uncover a new equilibria structure, torsional wrinkling, with the intriguing ability to focus gradients in filament tilt much like curvature-focusing for the analogous membrane. NSF (CAREER) DMR-0955760.

  16. Fuel bundle design for enhanced usage of plutonium fuel

    DOEpatents

    Reese, Anthony P.; Stachowski, Russell E.

    1995-01-01

    A nuclear fuel bundle includes a square array of fuel rods each having a concentration of enriched uranium and plutonium. Each rod of an interior array of the rods also has a concentration of gadolinium. The interior array of rods is surrounded by an exterior array of rods void of gadolinium. By this design, usage of plutonium in the nuclear reactor is enhanced.

  17. Fiber-bundle formalism for quantization in curved spaces

    NASA Astrophysics Data System (ADS)

    Wyrozumski, Tomasz

    1990-08-01

    We set up a geometrical formulation of the canonical quantization of a free Klein-Gordon field on a gravitational background. We introduce the notion of the Bogolubov bundle as the principal fiber bundle over the space of all Cauchy surfaces belonging to some fixed foliation of space-time, with the Bogolubov group as the structure group, as a tool in considering local Bogolubov transformations. Sections of the associated complex structure bundle have the meaning of attaching Hilbert spaces to Cauchy surfaces. We single out, as physical, sections defined by the equation of parallel transport on the Bogolubov bundle. The connection is then subjected to a certain nonlinear differential equation. We find a particular solution, which happens to coincide with a formula given by Parker for Robertson-Walker space-times. Finally, we adopt the adiabatic hypothesis as the physical input to the formalism and fix in this way a free parameter in the connection. Concluding, we comment on a possible geometrical interpretation of the regularization of the stress-energy tensor and on generalizations of the formalism toward quantum gravity.

  18. Metabolite Diffusion into Bundle Sheath Cells from C4 Plants

    PubMed Central

    Weiner, Hendrik; Burnell, James N.; Woodrow, Ian E.; Heldt, Hans W.; Hatch, Marshall D.

    1988-01-01

    The present studies provide the first measurements of the resistance to diffusive flux of metabolites between mesophyll and bundle sheath cells of C4 plants. Species examined were Panicum miliaceum, Urochloa panicoides, Atriplex spongiosa, and Zea mays. Diffusive flux of metabolites into isolated bundle sheath cells was monitored by following their metabolic transformation. Evidence was obtained that the observed rapid fluxes occurred via functional plasmodesmata. Diffusion constants were determined from the rate of transformation of limiting concentrations of metabolites via cytosolic enzymes with high potential velocities and favorable equilibrium constants. Values on a leaf chlorophyll basis ranged between 1 and 5 micromoles per minute per milligram of chlorophyll per millimolar gradient depending on the molecular weight of the metabolite and the source of bundle sheath cells. Diffusion of metabolites into these cells was unaffected by a wide variety of compounds including respiratory inhibitors, monovalent and divalent cations, and plant hormones, but it was interrupted by treatments inducing cell plasmolysis. The molecular weight exclusion limit for permeation of compounds into bundle sheath cells was in the range of 850 to 900. These cells provide an ideal system for the quantitative study of plasmodesmatal function. PMID:16666390

  19. Non-Euclidean geometry of twisted filament bundle packing

    PubMed Central

    Bruss, Isaac R.; Grason, Gregory M.

    2012-01-01

    Densely packed and twisted assemblies of filaments are crucial structural motifs in macroscopic materials (cables, ropes, and textiles) as well as synthetic and biological nanomaterials (fibrous proteins). We study the unique and nontrivial packing geometry of this universal material design from two perspectives. First, we show that the problem of twisted bundle packing can be mapped exactly onto the problem of disc packing on a curved surface, the geometry of which has a positive, spherical curvature close to the center of rotation and approaches the intrinsically flat geometry of a cylinder far from the bundle center. From this mapping, we find the packing of any twisted bundle is geometrically frustrated, as it makes the sixfold geometry of filament close packing impossible at the core of the fiber. This geometrical equivalence leads to a spectrum of close-packed fiber geometries, whose low symmetry (five-, four-, three-, and twofold) reflect non-Euclidean packing constraints at the bundle core. Second, we explore the ground-state structure of twisted filament assemblies formed under the influence of adhesive interactions by a computational model. Here, we find that the underlying non-Euclidean geometry of twisted fiber packing disrupts the regular lattice packing of filaments above a critical radius, proportional to the helical pitch. Above this critical radius, the ground-state packing includes the presence of between one and six excess fivefold disclinations in the cross-sectional order. PMID:22711799

  20. Anisotropic Turbulence Modeling for Accurate Rod Bundle Simulations

    SciTech Connect

    Baglietto, Emilio

    2006-07-01

    An improved anisotropic eddy viscosity model has been developed for accurate predictions of the thermal hydraulic performances of nuclear reactor fuel assemblies. The proposed model adopts a non-linear formulation of the stress-strain relationship in order to include the reproduction of the anisotropic phenomena, and in combination with an optimized low-Reynolds-number formulation based on Direct Numerical Simulation (DNS) to produce correct damping of the turbulent viscosity in the near wall region. This work underlines the importance of accurate anisotropic modeling to faithfully reproduce the scale of the turbulence driven secondary flows inside the bundle subchannels, by comparison with various isothermal and heated experimental cases. The very low scale secondary motion is responsible for the increased turbulence transport which produces a noticeable homogenization of the velocity distribution and consequently of the circumferential cladding temperature distribution, which is of main interest in bundle design. Various fully developed bare bundles test cases are shown for different geometrical and flow conditions, where the proposed model shows clearly improved predictions, in close agreement with experimental findings, for regular as well as distorted geometries. Finally the applicability of the model for practical bundle calculations is evaluated through its application in the high-Reynolds form on coarse grids, with excellent results. (author)

  1. Fiber-bundle formalism for quantization in curved spaces

    SciTech Connect

    Wyrozumski, T. )

    1990-08-15

    We set up a geometrical formulation of the canonical quantization of a free Klein-Gordon field on a gravitational background. We introduce the notion of the Bogolubov bundle as the principal fiber bundle over the space of all Cauchy surfaces belonging to some fixed foliation of space-time, with the Bogolubov group as the structure group, as a tool in considering local Bogolubov transformations. Sections of the associated complex structure bundle have the meaning of attaching Hilbert spaces to Cauchy surfaces. We single out, as physical, sections defined by the equation of parallel transport on the Bogolubov bundle. The connection is then subjected to a certain nonlinear differential equation. We find a particular solution, which happens to coincide with a formula given by Parker for Robertson-Walker space-times. Finally, we adopt the adiabatic hypothesis as the physical input to the formalism and fix in this way a free parameter in the connection. Concluding, we comment on a possible geometrical interpretation of the regularization of the stress-energy tensor and on generalizations of the formalism toward quantum gravity.

  2. Get ready: Bundled payments are in your future.

    PubMed

    2015-09-01

    The Centers for Medicare & Medicaid Services' (CMS') mandatory bundled payment pilot project makes clear that the agency intends to reform Medicare reimbursement. Hospitals in 75 geographic areas are required to participate in a five-year pilot project that puts them at risk for the cost of hip and knee replacements from the time of surgery until 90 days after discharge. Already, more than 6,500 providers are participating in the Bundled Payments for Care Improvement project, a voluntary program where participants can choose from 48 clinical episodes and four models. Even if they won't be part of a bundled payments arrangement, case managers need to shift their thinking to prepare for the future of reimbursement by developing close working relationships with post-acute providers, knowing the services and quality delivered by post-acute providers, and being aware of the costs for the entire episode of care. Case managers will not be able to handle all the responsibilities necessary in a bundled payment arrangement if they have large caseloads.

  3. Wire bundle formed into grids with minute interstices

    NASA Technical Reports Server (NTRS)

    Todd, H. H.

    1965-01-01

    Deforming the ends of a bundle of closely packed parallel wires to restrict the interstices to substantially uniform and minute dimensions produces grids or filters for ion engines. Porous metal structures made by this process are also used as fuel cell electrodes, diffusion membranes, and catalysts.

  4. Self-adjointness of the Gaffney Laplacian on Vector Bundles

    NASA Astrophysics Data System (ADS)

    Bandara, Lashi; Milatovic, Ognjen

    2015-12-01

    We study the Gaffney Laplacian on a vector bundle equipped with a compatible metric and connection over a Riemannian manifold that is possibly geodesically incomplete. Under the hypothesis that the Cauchy boundary is polar, we demonstrate the self-adjointness of this Laplacian. Furthermore, we show that negligible boundary is a necessary and sufficient condition for the self-adjointness of this operator.

  5. Product Bundling and Shared Information Goods: A Pricing Exercise

    ERIC Educational Resources Information Center

    Morrison, William G.

    2016-01-01

    In this article, the author describes an exercise in which two pricing problems (product bundling and the sharing of digital information goods) can be understood using the same analytical approach. The exercise allows students to calculate the correct numerical answers with relative ease, while the teaching plan demonstrates the importance of the…

  6. Exposure Control Using Adaptive Multi-Stage Item Bundles.

    ERIC Educational Resources Information Center

    Luecht, Richard M.

    This paper presents a multistage adaptive testing test development paradigm that promises to handle content balancing and other test development needs, psychometric reliability concerns, and item exposure. The bundled multistage adaptive testing (BMAT) framework is a modification of the computer-adaptive sequential testing framework introduced by…

  7. Formation and Dissociation of Sperm Bundles in Monotremes.

    PubMed

    Nixon, Brett; Ecroyd, Heath; Dacheux, Jean-Louis; Dacheux, Francoise; Labas, Valerie; Johnston, Steve D; Jones, Russell C

    2016-10-01

    Because monotremes are the earliest offshoot of the mammalian lineage, the platypus and short-beaked echidna were studied as model animals to assess the origin and biological significance of adaptations considered unique to therian mammals: epididymal sperm maturation and subsequent capacitation. We show that spermatozoa from both species assemble into bundles of approximately 100 cells during passage through the epididymis and that an epididymal protein-secreted protein, acidic, cysteine-rich (osteonectin; SPARC)-is involved in bundle formation. The bundles persisted during incubation in vitro for at least 1 h under conditions that capacitate therian spermatozoa, and then underwent a time-dependent dissociation to release spermatozoa capable of fertilization. Only after this dissociation could the spermatozoa bind to the perivitelline membrane of a hen's egg, display an altered form of motility reminiscent of hyperactivation, and be induced to undergo an acrosome reaction. It is concluded that the development of sperm bundles in the monotreme epididymis mandates that they require a time-dependent process to be capable of fertilizing an ovum. However, because this functional end point was achieved without overt changes in protein tyrosine phosphorylation (a hallmark of capacitation in therians), it is concluded that the process in monotremes is distinctly different from capacitation in therian mammals.

  8. Chest drain care bundle: Improving documentation and safety.

    PubMed

    Hutton, Joe; Graham, Selina

    2015-01-01

    Chest drain insertion is a common advanced procedure with a significant associated risk of pain, distress, and complications. Nationally, audit and recommendations from leading bodies have highlighted a number of safety concerns around chest drain insertion. Audit work has demonstrated poor levels of documentation; particularly around use of premedication, use of ultrasound guidance and consent. This has obvious potential consequences for patient safety and thus is an important target for improvement work. This project quantifies current standards of documentation and aims to improve this through a combination of accessible and easy to read guidelines, education, and the introduction of a chest drain insertion bundle. National best practice standards were identified through review of national guidance. Drain insertion was prospectively analysed over a three month period to establish baseline standards of documentation. This initial work was presented and a bundle and clinical guidelines produced. Chest drain insertion was then reaudited and assessed for improvement. Results demonstrated an improvement in many areas of documentation, pushing local results above the national average. However, only 40% of cases used the new bundle due to a mixture of staff rotation and an unexpectedly high proportion of drains inserted in non targeted areas including the emergency department, theatre, and intensive care. Despite this, the introduction of accessible guidance and bundle has significantly improved chest drain insertion documentation to the benefit of all.

  9. Almost Lie structures on an anchored Banach bundle

    NASA Astrophysics Data System (ADS)

    Cabau, P.; Pelletier, F.

    2012-11-01

    Under appropriate assumptions, we generalize the concept of linear almost Poisson structures, almost Lie algebroids, almost differentials in the framework of Banach anchored bundles and the relation between these objects. We then obtain an adapted formalism for mechanical systems which is illustrated by the evolutionary problem of the "Hilbert snake" as exposed in Pelletier and Saffidine (2011) [9].

  10. A comprehensive in-pile test of PWR fuel bundle

    NASA Astrophysics Data System (ADS)

    Kang, Rixin; Zhang, Shucheng; Chen, Dianshan

    1991-02-01

    An in-pile test of PWR fuel bundle has been conducted in HWRR at IAE of China. This paper describes the structure of the test bundle (3 × 3-2), fabrication process and quality control of the fuel rod, irradiation conditions and the main Post Irradiation Examination (PIE) results. The test fuel bundle was irradiated under the PWR operation and water chemistry conditions with an average linear power of 381 W/cm and reached an average burnup of 25010 MWd/tU of the fuel bundle. After the test, destructive and non-destructive examination of the fuel rods was conducted at hot laboratories. The fission gas release was 10.4-23%. The ridge height of cladding was 3 to 8 μm. The hydrogen content of the cladding was 80 to 140 ppm. The fuel stack height was increased by 2.9 to 3.3 mm. The relative irradiation growth was about 0.11 to 0.17% of the fuel rod length. During the irradiation test, no fuel rod failure or other abnormal phenomena had been found by the on-line fuel failure monitoring system of the test loop and water sampling analysis. The structure of the test fuel assembly was left undamaged without twist and detectable deformation.

  11. 3-dimensional bundle adjustments in industrial metrology: A comparison

    SciTech Connect

    Gaydosh, M.; LeCocq, C.; Ruland, R.; Wand, B.

    1992-07-01

    Several theodolite measurement systems are available for use in the industrial metrology market. Many of them offer a rigorous 3-dimensional bundle adjustment routine. In this paper several systems in use and available for evaluation purposes at the Stanford Linear Accelerator Center will be tested and their results compared.

  12. Fission Yeast Scp3 Potentially Maintains Microtubule Orientation through Bundling

    PubMed Central

    Ozaki, Kanako; Chikashige, Yuji; Hiraoka, Yasushi; Matsumoto, Tomohiro

    2015-01-01

    Microtubules play important roles in organelle transport, the maintenance of cell polarity and chromosome segregation and generally form bundles during these processes. The fission yeast gene scp3+ was identified as a multicopy suppressor of the cps3-81 mutant, which is hypersensitive to isopropyl N-3-chlorophenylcarbamate (CIPC), a poison that induces abnormal multipolar spindle formation in higher eukaryotes. In this study, we investigated the function of Scp3 along with the effect of CIPC in the fission yeast Schizosaccharomyces pombe. Microscopic observation revealed that treatment with CIPC, cps3-81 mutation and scp3+ gene deletion disturbed the orientation of microtubules in interphase cells. Overexpression of scp3+ suppressed the abnormal orientation of microtubules by promoting bundling. Functional analysis suggested that Scp3 functions independently from Ase1, a protein largely required for the bundling of the mitotic spindle. A strain lacking the ase1+ gene was more sensitive to CIPC, with the drug affecting the integrity of the mitotic spindle, indicating that CIPC has a mitotic target that has a role redundant with Ase1. These results suggested that multiple systems are independently involved to ensure microtubule orientation by bundling in fission yeast. PMID:25767875

  13. A Method of Assembling Compact Coherent Fiber-Optic Bundles

    NASA Technical Reports Server (NTRS)

    Martin, Stefan; Liu, Duncan; Levine, Bruce Martin; Shao, Michael; Wallace, James

    2007-01-01

    A method of assembling coherent fiber-optic bundles in which all the fibers are packed together as closely as possible is undergoing development. The method is based, straightforwardly, on the established concept of hexagonal close packing; hence, the development efforts are focused on fixtures and techniques for practical implementation of hexagonal close packing of parallel optical fibers.

  14. Masquerading Bundle Branch Block: A Poor Prognostic Sign Revisited

    PubMed Central

    Dhanse, Suheil; Kareem, Hashir; Devasia, Tom

    2016-01-01

    Masquerading bundle branch block is a rare but important finding on the Electrocardiogram (ECG). It is an indication of severe and diffuse conduction system disease and usually indicates poor prognosis. The precordial leads show a Right Bundle Branch Block (RBBB) pattern while the limb leads resemble a Left Bundle Branch Block (LBBB). This finding on an ECG is almost invariably associated with severe underlying heart disease. It is extremely important to be aware of this finding as it is a marker of poor cardiac outcomes. We report the case of a 68-year-old gentleman, who presented with progressive dyspnoea on exertion over three months. ECG showed a broad QRS complex with a RBBB pattern on the precordial leads and a LBBB pattern on the limb leads (suggestive of masquerading bundle branch block). A coronary angiogram revealed severe Triple Vessel Disease (TVD). The patient was scheduled for an early Coronary Artery By-Pass Grafting Surgery. However, his clinical condition deteriorated and he died while awaiting the surgery. PMID:27790494

  15. Appraising Lexical Bundles in Mathematics Classroom Discourse: Obligation and Choice

    ERIC Educational Resources Information Center

    Herbel-Eisenmann, Beth; Wagner, David

    2010-01-01

    Working from a large corpus of transcripts from secondary mathematics classrooms, we identify patterns of speech that encode interpersonal positioning. We extend our analysis from a previous article (Herbel-Eisenmann, Wagner & Cortes, Educ Stud Math, 2010, in press), in which we introduced a concept from corpus linguistics--a "lexical bundle,"…

  16. Hair Cells: Bundles, Tuning, Transduction—A Moderated Discussion

    NASA Astrophysics Data System (ADS)

    Karavitaki, K. Domenica; Ricci, Anthony J.

    2011-11-01

    A discussion moderated by the authors on the topic "Hair Cells: Bundles, Tuning, Transduction" was held on 17 July 2011 at the 11th International Mechanics of Hearing Workshop in Williamstown, Massachusetts. The paper provides an edited transcript of the session.

  17. Product Bundling and Shared Information Goods: A Pricing Exercise

    ERIC Educational Resources Information Center

    Morrison, William G.

    2016-01-01

    In this article, the author describes an exercise in which two pricing problems (product bundling and the sharing of digital information goods) can be understood using the same analytical approach. The exercise allows students to calculate the correct numerical answers with relative ease, while the teaching plan demonstrates the importance of the…

  18. Vertical, Bubbly, Cross-Flow Characteristics over Tube Bundles

    NASA Astrophysics Data System (ADS)

    Iwaki, C.; Cheong, K. H.; Monji, H.; Matsui, G.

    2005-12-01

    Two-phase flow over tube bundles is commonly observed in shell and tube-type heat exchangers. However, only limited amount of data concerning flow pattern and void fraction exists due to the flow complexity and the difficulties in measurement. The detailed flow structure in tube bundles needs to be understood for reliable and effective design. Therefore, the objective of this study was to clarify the two-phase structure of cross-flow in tube bundles by PIV. Experiments were conducted using two types of models, namely in-line and staggered arrays with a pitch-to-diameter ratio of 1.5. Each test section contains 20 rows of five 15 mm O.D. tubes in each row. The experiment’s data were obtained under very low void fraction (α<0.02). Liquid and gas velocity data in the whole flow field were measured successfully by optical filtering and image processing. The structures of bubbly flow in the two different configurations of tube bundles were described in terms of the velocity vector field, turbulence intensity and void fraction.

  19. Double helicenes

    NASA Astrophysics Data System (ADS)

    Bachrach, Steven M.

    2016-12-01

    The even double helicenes with 4-12 phenyl groups in each helix were examined at B3LYP-D3/6-311G(d). The double helicenes with 4-10 phenyl rings are less than twice as strained as their component helicenes; the strain results from twisting about the shared naphthyl moiety, with accompanying loss of aromaticity. These compounds should be reasonable synthetic targets, and computed NMR shifts are provided to aid in their characterization.

  20. Coolant mixing in LMFBR rod bundles and outlet plenum mixing transients. Progress report

    SciTech Connect

    Todreas, N.E.; Golay, M.W.; Wold, L.

    1981-02-01

    Four tasks are reported on: bundle geometry (wrapped and bare rods), subchannel geometry (bare rods), LMFBR outlet plenum flow mixing, and theoretical determination of local temperature fields in LMFBR fuel rod bundles. (DLC)

  1. 76 FR 53137 - Bundled Payments for Care Improvement Initiative: Request for Applications

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-25

    ... HUMAN SERVICES Centers for Medicare & Medicaid Services Bundled Payments for Care Improvement Initiative... of the initial four models under the Bundled Payments for Care Improvement initiative beginning in... described on the CMS Innovation Center Web site...

  2. Electron diffraction and microscopy of single-wall carbon nanotube bundles produced by different methods

    NASA Astrophysics Data System (ADS)

    Colomer, J.-F.; Henrard, L.; Lambin, Ph.; van Tendeloo, G.

    2002-05-01

    The atomic structure of single-wall carbon nanotube bundles produced by three different techniques (laser ablation, electric arc discharge and catalytic chemical vapor deposition (CCVD)) has been characterized by electron diffraction and microscopy. Information on the helicity and the lattice packing has been obtained. Concerning the helicity, small bundles produced by CCVD exhibit only one or two tube helicities within a single bundle. The diffraction patterns of laser-ablation produced bundles also present well-defined but more diversified chiralities within a single bundle. By contrast the data acquired on bundles formed by arc discharge show a more diffuse pattern, characteristic of a random chirality dispersion within a single bundle. Concerning the lattice packing, informations are obtained via a detailed study of the equatorial line of the diffraction pattern for bundles produced by the three techniques. This electron diffraction study is completed by high-resolution electron microscopy.

  3. 76 FR 8368 - Price Index Adjustments for Contribution and Expenditure Limits and Lobbyist Bundling Disclosure...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-14

    ... Price Index Adjustments for Contribution and Expenditure Limits and Lobbyist Bundling Disclosure... limits and lobbyist bundling disclosure threshold. SUMMARY: As mandated by provisions of the Federal...'' or ``the Commission'') is adjusting certain contribution and expenditure limits and the lobbyist...

  4. [Successful use of an AED following anterior myocardial infarction].

    PubMed

    Harding, Ulf; Reifferscheid, Florian; von Olshausen, Klaus

    2007-05-01

    A participant of the annual Hamburg marathon collapses on the finish line. Medics at the scene find a conscious patient and prepare transport to the finish area medical center. During transport the patient becomes unconscious and pulseless. The medics immediately perform basic life support and cardiopulmonary resuscitation (CPR). An automated external defibrillator (AED) is attached and after analysis of the patient}s heart rhythm the patient is defibrillated twice. The ambulance service reach the scene with a delay. The emergency physician}s ECG shows ventricular fibrillation (VF) and two more defibrillations are delivered. Return of spontaneous circulation can be achieved. After stabilisation the patient is taken to hospital by ambulance. The ECG shows an anterior myocardial infarction and right bundle-branch block. The coronary angioplasty (PTCA) shows single-vessel disease with complete stenosis of the proximal part of the anterior interventricular branch. Revasucarisation is successful and a coronary stent is applied. The patient survives neurologically intact. This case report demonstrates the importance of readily available AED and specially trained medics. By immediately using the AED this patient was defibrillated before the ambulance service and emergency physician arrived at the scene. Spontaneous circulation was restored.

  5. Double Ramification Cycles and Quantum Integrable Systems

    NASA Astrophysics Data System (ADS)

    Buryak, Alexandr; Rossi, Paolo

    2016-03-01

    In this paper, we define a quantization of the Double Ramification Hierarchies of Buryak (Commun Math Phys 336:1085-1107, 2015) and Buryak and Rossi (Commun Math Phys, 2014), using intersection numbers of the double ramification cycle, the full Chern class of the Hodge bundle and psi-classes with a given cohomological field theory. We provide effective recursion formulae which determine the full quantum hierarchy starting from just one Hamiltonian, the one associated with the first descendant of the unit of the cohomological field theory only. We study various examples which provide, in very explicit form, new (1+1)-dimensional integrable quantum field theories whose classical limits are well-known integrable hierarchies such as KdV, Intermediate Long Wave, extended Toda, etc. Finally, we prove polynomiality in the ramification multiplicities of the integral of any tautological class over the double ramification cycle.

  6. Pressure and Flow Relations in Vascular Bundles of the Tomato Plant

    PubMed Central

    Dimond, A. E.

    1966-01-01

    In the tomato plant water flows through primary xylem in accordance with Poiseuille's law. This relation and the analogy between Poiseuille's and Ohm's law were employed to calculate rates of flow and differences in pressure within vascular bundles when transpiration rates from individual leaves were known. The resistance of vascular bundles to flow was calculated from a modification of Poiseuille's law and from measurements of vessels in all bundles. The rates of flow in all bundles were derived from a set of simultaneous linear equations of flow, written to correspond with the nature of the vascular network. Values of the difference in pressure associated with flow in bundles were derived from resistances and flow rates in individual bundles. These agreed substantially with values observed in a comparable plant. In large bundles, vessels occur in a frequency distribution that is approximately normal with respect either to the logarithms of their radii or to the fourth power of their radii. The largest vessels in a bundle transport most of the water when they are functioning. The tomato plant contains 2 types of vascular bundle. The large bundles of the stem form a network by joining above each node in combinations of 2 at a time. The small bundles of the stem and petiolar bundles are independent of other bundles from their origins at junctions to their termini. The small bundles offer high resistance to flow, whereas the resistance of large bundles is low. The average conductance of large bundles decreases from the base to the apex of the stem. That of small vascular bundles remains low and more or less constant throughout the plant. Only a small difference in pressure is required to maintain flow in large bundles. For lower leaves, the driving pressure required to move water to the base of a petiole is considerably less than that which moves water through petioles. The difference in pressure that maintains flow increases steadily for successively higher nodes

  7. Bacterial flagella rotating in bundles: a study in helical geometry.

    PubMed Central

    Macnab, R M

    1977-01-01

    Bacterial flagella are semi-rigid helices that undergo true rotation. In peritrichously flagellated bacteria (e.g., Escherichia and Salmonella) there are many flagella on each cell; during translational cell movement these operate as a coordinated bundle that actively disperses upon reversal of the rotation sense. The dynamic behavior of a set of helices originating on separate rotational axes is explored by a working model, geometrical analysis, and hydrodynamic calculations. A critical relationship exists between the interaxial separation and phase difference of parallel helices with overlapping domains; in the subcritical case the filaments are not intertwisted, whereas in the supercritical case they are intertwisted in the same sense (left-handed) as the helices, with one twist per helical turn. During counter-clockwise rotation (the sense operative in forward swimming) any preexisting twists of this kind are automatically cancelled and the helices brought progressively into phase. Hydrodynamic calculations suggest that some wrapping then occurs in a right-handed sense, opposite to that of the helices; this necessitates a distortion from true helical geometry which is minimized by maintaining a coaxial in-phase relationship. A highly coordinated helical bundle results that is capable of operating smoothly for an indefinite period, in agreement with the observed behavior of swimming bacteria. During reverse rotation, the supercritical case develops to cause jamming of the bundle, as has been observed with bacteria in high-viscosity medium. The explosive dispersal of the bundle during reversal in low-viscosity medium is a consequence of a complicating phenomenon, namely, a drastic change in flagellar quaternary structure. The overall conclusion is that bundle formation and function are perfectly compatible with a rotational mechanism for the individual flagella. Images PMID:264676

  8. Infinitesimal moduli of G2 holonomy manifolds with instanton bundles

    NASA Astrophysics Data System (ADS)

    de la Ossa, Xenia; Larfors, Magdalena; Svanes, Eirik E.

    2016-11-01

    We describe the infinitesimal moduli space of pairs ( Y, V) where Y is a manifold with G 2 holonomy, and V is a vector bundle on Y with an instanton connection. These structures arise in connection to the moduli space of heterotic string compactifications on compact and non-compact seven dimensional spaces, e.g. domain walls. Employing the canonical G 2 cohomology developed by Reyes-Carrión and Fernández and Ugarte, we show that the moduli space decomposes into the sum of the bundle moduli {H}_{{overset{ěe }{d}}_A}^1(Y,End(V)) plus the moduli of the G 2 structure preserving the instanton condition. The latter piece is contained in {H}_{overset{ěe }{d}θ}^1(Y,TY) , and is given by the kernel of a map overset{ěe }{F} which generalises the concept of the Atiyah map for holomorphic bundles on complex manifolds to the case at hand. In fact, the map overset{ěe }{F} is given in terms of the curvature of the bundle and maps {H}_{overset{ěe }{d}θ}^1(Y,TY) into {H}_{{overset{ěe }{d}}_A}^2(Y,End(V)) , and moreover can be used to define a cohomology on an extension bundle of TY by End( V). We comment further on the resemblance with the holomorphic Atiyah algebroid and connect the story to physics, in particular to heterotic compactifications on ( Y, V) when α' = 0.

  9. Lower complication rates for cranioplasty with peri-operative bundle.

    PubMed

    Le, Catherine; Guppy, Kern H; Axelrod, Yekaterina V; Hawk, Mark W; Silverthorn, James; Inacio, Maria C; Akins, Paul T

    2014-05-01

    The overall benefits of craniectomy must include procedural risks from cranioplasty. Cranioplasty carries a high risk of surgical site infections (SSI) particularly with antibiotic resistant bacteria. The goal of this study was to measure the effect of a cranioplasty bundle on peri-operative complications. The authors queried a prospective, inpatient neurosurgery database at Kaiser Sacramento Medical Center for craniectomy and cranioplasty over a 7 year period. 57 patients who underwent cranioplasties were identified. A retrospective chart review was completed for complications, including surgical complications such as SSI, wound dehiscence, and re-do cranioplasty. We measured cranioplasty complication rates before and after implementation of a peri-operative bundle, which consisted of peri-operative vancomycin (4 doses), a barrier dressing through post-operative day (POD) 3, and de-colonization of the surgical incision using topical chlorhexidine from POD 4 to 7. The rate of MRSA colonization in cranioplasty patients is three times higher than the average seen on ICU admission screening (19% vs. 6%). The cranioplasty surgical complication rate was 22.8% and SSI rate was 10.5%. The concurrent SSI rate for craniectomy was 1.9%. Organisms isolated were methicillin-resistant Staphylococcus aureus (4), methicillin-sensitive S. aureus (1), Propionibacterium acnes (1), and Escherichia coli (1). Factors associated with SSI were peri-operative vancomycin (68.6% vs. 16.7%, p=0.0217). Complication rates without (n=21) and with (n=36) the bundle were: SSI (23.8% vs. 2.8%, p=0.0217) and redo cranioplasty (19% vs. 0%, p=0.0152). Bundle use did not affect rates for superficial wound dehiscence, seizures, or hydrocephalus. The cranioplasty bundle was associated with reduced SSI rates and the need for re-do cranioplasties. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Central line maintenance bundles and CLABSIs in ambulatory oncology patients.

    PubMed

    Rinke, Michael L; Bundy, David G; Chen, Allen R; Milstone, Aaron M; Colantuoni, Elizabeth; Pehar, Miriana; Herpst, Cynthia; Fratino, Lisa; Miller, Marlene R

    2013-11-01

    Pediatric oncology patients are frequently managed with central lines as outpatients, and these lines confer significant morbidity in this immune-compromised population. We aimed to investigate whether a multidisciplinary, central line maintenance care bundle reduces central line-associated bloodstream infections (CLABSIs) and bacteremias in ambulatory pediatric oncology patients. We conducted an interrupted time-series study of a maintenance bundle concerning all areas of central line care. Each of 3 target groups (clinic staff, homecare agency nurses, and patient families) (1) received training on the bundle and its importance, (2) had their practice audited, and (3) were shown CLABSI rates through graphs, in-service training, and bulletin boards. CLABSI and bacteremia person-time incidence rates were collected for 23 months before and 24 months after beginning the intervention and were compared by using a Poisson regression model. The mean CLABSI rate decreased by 48% from 0.63 CLABSIs per 1000 central line days at baseline to 0.32 CLABSIs per 1000 central line days during the intervention period (P = .005). The mean bacteremia rate decreased by 54% from 1.27 bacteremias per 1000 central line days at baseline to 0.59 bacteremias per 1000 central line days during the intervention period (P < .001). Implementation of a multidisciplinary, central line maintenance care bundle significantly reduced CLABSI and bacteremia person-time incidence rates in ambulatory pediatric oncology patients with central lines. Further research is needed to determine if maintenance care bundles reduce ambulatory CLABSIs and bacteremia in other adult and pediatric populations.

  11. Central Line Maintenance Bundles and CLABSIs in Ambulatory Oncology Patients

    PubMed Central

    Bundy, David G.; Chen, Allen R.; Milstone, Aaron M.; Colantuoni, Elizabeth; Pehar, Miriana; Herpst, Cynthia; Fratino, Lisa; Miller, Marlene R.

    2013-01-01

    OBJECTIVE: Pediatric oncology patients are frequently managed with central lines as outpatients, and these lines confer significant morbidity in this immune-compromised population. We aimed to investigate whether a multidisciplinary, central line maintenance care bundle reduces central line–associated bloodstream infections (CLABSIs) and bacteremias in ambulatory pediatric oncology patients. METHODS: We conducted an interrupted time-series study of a maintenance bundle concerning all areas of central line care. Each of 3 target groups (clinic staff, homecare agency nurses, and patient families) (1) received training on the bundle and its importance, (2) had their practice audited, and (3) were shown CLABSI rates through graphs, in-service training, and bulletin boards. CLABSI and bacteremia person-time incidence rates were collected for 23 months before and 24 months after beginning the intervention and were compared by using a Poisson regression model. RESULTS: The mean CLABSI rate decreased by 48% from 0.63 CLABSIs per 1000 central line days at baseline to 0.32 CLABSIs per 1000 central line days during the intervention period (P = .005). The mean bacteremia rate decreased by 54% from 1.27 bacteremias per 1000 central line days at baseline to 0.59 bacteremias per 1000 central line days during the intervention period (P < .001). CONCLUSIONS: Implementation of a multidisciplinary, central line maintenance care bundle significantly reduced CLABSI and bacteremia person-time incidence rates in ambulatory pediatric oncology patients with central lines. Further research is needed to determine if maintenance care bundles reduce ambulatory CLABSIs and bacteremia in other adult and pediatric populations. PMID:24101764

  12. Geometric principles in the assembly of α-helical bundles.

    PubMed

    Pratap, J V; Luisi, B F; Calladine, C R

    2013-06-28

    α-Helical coiled coils are usually stabilized by hydrophobic interfaces between the two constituent α-helices, in the form of 'knobs-into-holes' packing of non-polar residues arranged in repeating heptad patterns. Here we examine the corresponding 'hydrophobic cores' that stabilize bundles of four α-helices. In particular, we study three different kinds of bundle, involving four α-helices of identical sequence: two pack in a parallel and one in an anti-parallel orientation. We point out that the simplest way of understanding the packing of these 4-helix bundles is to use Crick's original idea that the helices are held together by 'hydrophobic stripes', which are readily visualized on the cylindrical surface lattice of the α-helices; and that the 'helix-crossing angle'--which determines, in particular, whether supercoiling is left- or right-handed--is fixed by the slope of the lattice lines that contain the hydrophobic residues. In our three examples the constituent α-helices have hydrophobic repeat patterns of 7, 11 and 4 residues, respectively; and we associate the different overall conformations with 'knobs-into-holes' packing along the 7-, 11- and 4-start lines, respectively, of the cylindrical surface lattices of the constituent α-helices. For the first two examples, all four interfaces between adjacent helices are geometrically equivalent; but in the third, one of the four interfaces differs significantly from the others. We provide a geometrical explanation for this non-equivalence in terms of two different but equivalent ways of assembling this bundle, which may possibly constitute a bistable molecular 'switch' with a coaxial throw of about 12 Å. The geometrical ideas that we deploy in this paper provide the simplest and clearest description of the structure of helical bundles. In an appendix, we describe briefly a computer program that we have devised in order to search for 'knobs-into-holes' packing between α-helices in proteins.

  13. 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.

  14. Coupling a sensory hair-cell bundle to cyber clones enhances nonlinear amplification

    PubMed Central

    Barral, Jérémie; Dierkes, Kai; Lindner, Benjamin; Jülicher, Frank; Martin, Pascal

    2010-01-01

    The vertebrate ear benefits from nonlinear mechanical amplification to operate over a vast range of sound intensities. The amplificatory process is thought to emerge from active force production by sensory hair cells. The mechano-sensory hair bundle that protrudes from the apical surface of each hair cell can oscillate spontaneously and function as a frequency-selective, nonlinear amplifier. Intrinsic fluctuations, however, jostle the response of a single hair bundle to weak stimuli and seriously limit amplification. Most hair bundles are mechanically coupled by overlying gelatinous structures. Here, we assayed the effects of mechanical coupling on the hair-bundle amplifier by combining dynamic force clamp of a hair bundle from the bullfrog’s saccule with real-time stochastic simulations of hair-bundle mechanics. This setup couples the hair bundle to two virtual hair bundles, called cyber clones, and mimics a situation in which the hair bundle is elastically linked to two neighbors with similar characteristics. We found that coupling increased the coherence of spontaneous hair-bundle oscillations. By effectively reducing noise, the synergic interplay between the hair bundle and its cyber clones also enhanced amplification of sinusoidal stimuli. All observed effects of coupling were in quantitative agreement with simulations. We argue that the auditory amplifier relies on hair-bundle cooperation to overcome intrinsic noise limitations and achieve high sensitivity and sharp frequency selectivity. PMID:20404191

  15. Exploring Differential Bundle Functioning in Mathematics by Gender: The Effect of Hierarchical Modelling

    ERIC Educational Resources Information Center

    Ong, Yoke Mooi; Williams, Julian; Lamprianou, Iasonas

    2013-01-01

    Researchers interested in exploring substantive group differences are increasingly attending to bundles of items (or testlets): the aim is to understand how gender differences, for instance, are explained by differential performances on different types or bundles of items, hence differential bundle functioning (DBF). Some previous work has…

  16. Coupling a sensory hair-cell bundle to cyber clones enhances nonlinear amplification.

    PubMed

    Barral, Jérémie; Dierkes, Kai; Lindner, Benjamin; Jülicher, Frank; Martin, Pascal

    2010-05-04

    The vertebrate ear benefits from nonlinear mechanical amplification to operate over a vast range of sound intensities. The amplificatory process is thought to emerge from active force production by sensory hair cells. The mechano-sensory hair bundle that protrudes from the apical surface of each hair cell can oscillate spontaneously and function as a frequency-selective, nonlinear amplifier. Intrinsic fluctuations, however, jostle the response of a single hair bundle to weak stimuli and seriously limit amplification. Most hair bundles are mechanically coupled by overlying gelatinous structures. Here, we assayed the effects of mechanical coupling on the hair-bundle amplifier by combining dynamic force clamp of a hair bundle from the bullfrog's saccule with real-time stochastic simulations of hair-bundle mechanics. This setup couples the hair bundle to two virtual hair bundles, called cyber clones, and mimics a situation in which the hair bundle is elastically linked to two neighbors with similar characteristics. We found that coupling increased the coherence of spontaneous hair-bundle oscillations. By effectively reducing noise, the synergic interplay between the hair bundle and its cyber clones also enhanced amplification of sinusoidal stimuli. All observed effects of coupling were in quantitative agreement with simulations. We argue that the auditory amplifier relies on hair-bundle cooperation to overcome intrinsic noise limitations and achieve high sensitivity and sharp frequency selectivity.

  17. Exploring Differential Bundle Functioning in Mathematics by Gender: The Effect of Hierarchical Modelling

    ERIC Educational Resources Information Center

    Ong, Yoke Mooi; Williams, Julian; Lamprianou, Iasonas

    2013-01-01

    Researchers interested in exploring substantive group differences are increasingly attending to bundles of items (or testlets): the aim is to understand how gender differences, for instance, are explained by differential performances on different types or bundles of items, hence differential bundle functioning (DBF). Some previous work has…

  18. A Nerve Conduit Containing a Vascular Bundle and Implanted With Bone Marrow Stromal Cells and Decellularized Allogenic Nerve Matrix.

    PubMed

    Kaizawa, Yukitoshi; Kakinoki, Ryosuke; Ikeguchi, Ryosuke; Ohta, Soichi; Noguchi, Takashi; Takeuchi, Hisataka; Oda, Hiroki; Yurie, Hirofumi; Matsuda, Shuichi

    2017-02-16

    Cells, scaffolds, growth factors, and vascularity are essential for nerve regeneration. Previously, we reported that the insertion of a vascular bundle and the implantation of bone marrow-derived mesenchymal stem cells (BM-MSCs) into a nerve conduit promoted peripheral nerve regeneration. In this study, the efficacy of nerve conduits containing a vascular bundle, BM-MSCs, and thermally decellularized allogenic nerve matrix (DANM) was investigated using a rat sciatic nerve model with a 20-mm defect. Lewis rats were used as the sciatic nerve model and for the preparation of BM-MSCs, and Dark Agouti rats were used for the preparation of the DANM. The revascularization and the immunogenicity of the DANM were investigated histologically. The regeneration of nerves through nerve conduits containing vessels, BM-MSCs, and DANM (VBD group) was evaluated based on electrophysiological, morphometric, and reinnervated muscle weight measurements and compared with that of vessel-containing conduits that were implanted with BM-MSCs (VB group). The DANM that was implanted into vessel-containing tubes (VCTs) was revascularized by neovascular vessels that originated from the inserted vascular bundle 5-7 days after surgery. The number of CD8+ cells found in the DANM in the VCT was significantly smaller than that detected in the untreated allogenic nerve segment. The regenerated nerve in the VBD group was significantly superior to that in the VB group with regard to the amplitude of the compound muscle action potential detected in the pedal adductor muscle; the number, diameter, and myelin thickness of the myelinated axons; and the tibialis anterior muscle weight at 12 and 24 weeks. The additional implantation of the DANM into the BM-MSC-implanted VCT optimized the axonal regeneration through the conduit. Nerve conduits constructed with vascularity, cells, and scaffolds could be an effective strategy for the treatment of peripheral nerve injuries with significant segmental defects.

  19. Isopeptide bonds of the major pilin protein BcpA influence pilus structure and bundle formation on the surface of Bacillus cereus

    SciTech Connect

    Hendrickx, Antoni P.A.; Poor, Catherine B.; Jureller, Justin E.; Budzik, Jonathan M.; He, Chuan; Schneewind, Olaf

    2012-09-05

    Bacillus cereus strains elaborate pili on their surface using a mechanism of sortase-mediated cross-linking of major and minor pilus components. Here we used a combination of electron microscopy and atomic force microscopy to visualize these structures. Pili occur as single, double or higher order assemblies of filaments formed from monomers of the major pilin, BcpA, capped by the minor pilin, BcpB. Previous studies demonstrated that within assembled pili, four domains of BcpA -- CNA{sub 1}, CNA{sub 2}, XNA and CNA{sub 3} -- each acquire intramolecular lysine-asparagine isopeptide bonds formed via catalytic glutamic acid or aspartic acid residues. Here we showed that mutants unable to form the intramolecular isopeptide bonds in the CNA2 or CNA3 domains retain the ability to form pilus bundles. A mutant lacking the CNA{sub 1} isopeptide bond assembled deformed pilin subunits that failed to associate as bundles. X-ray crystallography revealed that the BcpA variant Asp{sup 312}Ala, lacking an aspartyl catalyst, did not generate the isopeptide bond within the jelly-roll structure of XNA. The Asp{sup 312}Ala mutant was also unable to form bundles and promoted the assembly of deformed pili. Thus, structural integrity of the CNA{sub 1} and XNA domains are determinants for the association of pili into higher order bundle structures and determine native pilus structure.

  20. [Double responses].

    PubMed

    Motté, G; Dinanian, S; Sebag, C; Drieu, L; Slama, M

    1995-12-01

    Double response is a rare electrocardiographic phenomenon requiring two atrioventricular conduction pathways with very different electrophysiological properties. Double ventricular responses are the usual manifestation: an atrial depolarisation (spontaneous or provoked, anticipated or not) is followed by a first ventricular response dependent on an accessory pathway or a rapid nodal pathway and then a second response resulting from sufficiently delayed transmission through a nodal pathway for the ventricles to have recovered their excitability when the second wave of activation reaches them. A simple curiosity when isolated and occurring under unusual conditions, particularly during electrophysiological investigation of the Wolff-Parkinson-White syndrome, the double response may initiate symptomatic non-reentrant junctional tachycardia when associated with nodal duality and repeating from atria in sinus rhythm. The functional incapacity and resistance to antiarrhythmic therapy may require referral for ablation of the slow pathway.

  1. Steady-state stiffness of utricular hair cells depends on macular location and hair bundle structure

    PubMed Central

    Spoon, Corrie; Moravec, W. J.; Rowe, M. H.; Grant, J. W.

    2011-01-01

    Spatial and temporal properties of head movement are encoded by vestibular hair cells in the inner ear. One of the most striking features of these receptors is the orderly structural variation in their mechanoreceptive hair bundles, but the functional significance of this diversity is poorly understood. We tested the hypothesis that hair bundle structure is a significant contributor to hair bundle mechanics by comparing structure and steady-state stiffness of 73 hair bundles at varying locations on the utricular macula. Our first major finding is that stiffness of utricular hair bundles varies systematically with macular locus. Stiffness values are highest in the striola, near the line of hair bundle polarity reversal, and decline exponentially toward the medial extrastriola. Striolar bundles are significantly more stiff than those in medial (median: 8.9 μN/m) and lateral (2.0 μN/m) extrastriolae. Within the striola, bundle stiffness is greatest in zone 2 (106.4 μN/m), a band of type II hair cells, and significantly less in zone 3 (30.6 μN/m), which contains the only type I hair cells in the macula. Bathing bundles in media that break interciliary links produced changes in bundle stiffness with predictable time course and magnitude, suggesting that links were intact in our standard media and contributed normally to bundle stiffness during measurements. Our second major finding is that bundle structure is a significant predictor of steady-state stiffness: the heights of kinocilia and the tallest stereocilia are the most important determinants of bundle stiffness. Our results suggest 1) a functional interpretation of bundle height variability in vertebrate vestibular organs, 2) a role for the striola in detecting onset of head movement, and 3) the hypothesis that differences in bundle stiffness contribute to diversity in afferent response dynamics. PMID:21918003

  2. Heterotic warped Eguchi-Hanson spectra with five-branes and line bundles

    NASA Astrophysics Data System (ADS)

    Carlevaro, Luca; Nibbelink, Stefan Groot

    2013-10-01

    We consider heterotic strings on a warped Eguchi-Hanson space with five-brane and line bundle gauge fluxes. The heterotic string admits an exact CFT description in terms of an asymmetrically gauged WZW model, in a specific double scaling limit in which the blow-up radius and the string scale are sent to zero simultaneously. This allows us to compute the perturbative 6D spectra for these models in two independent fashions: i) Within the supergravity approximation we employ a representation dependent index; ii) In the double scaling limit we determine all marginal vertex operators of the coset CFT. To achieve agreement between the supergravity and the CFT spectra, we conjecture that the untwisted and the twisted CFT states correspond to the same set of hyper multiplets in supergravity. This is in a similar spirit as a conjectured duality between asymptotically linear dilaton CFTs and little string theory living on NS-five-branes. As the five-brane charge is non-vanishing, heterotic (anti-)five-branes have to be added in order to cancel irreducible gauge anomalies. The local spectra can be combined in such a way that supersymmetry is preserved on the compact resolved orbifold by choosing the local gauge fluxes appropriately.

  3. Preprosthetic movement of anterior teeth.

    PubMed

    Melsen, B

    1982-05-01

    Preprosthetic movement of anterior teeth is often performed on patients with missing anterior teeth, providing a better basis for subsequent bridgework. This can often be achieved by horizontal tooth movements of a tipping or translatory art whilst other patients present problems of a vertical nature with a deep overbite inconsistent with a healthy periodontal status. Intrusive tooth movements are needed as changes in facial height are not tolerated. The importance of understanding the biological basis for tooth movements in the planning of the biomechanics is stressed. Forces should be monitored according to the amount of general and local bone loss.

  4. A study of ventricular contraction sequence in complete right bundle branch block by phase analysis.

    PubMed

    Takeda, T; Toyama, H; Iida, K; Masuoka, T; Ajisaka, R; Kuga, K; Satoh, M; Sugahara, S; Jin, W; Ishikawa, N

    1991-03-01

    Twenty-four patients with complete right bundle branch block (CRBBB) combined with and without left axis deviation (LAD) on ECG, were compared with 17 normal subjects to evaluate the right ventricular contraction sequence and pattern in detail. Blood pool scintigrams were obtained in the left anterior oblique projection, and these images were analyzed by first component Fourier harmonics. In the normal subjects, the phase value distribution representing the pattern of ventricular contraction was almost homogeneous in both the right and left ventricles (RV & LV). In the CRBBB patients without LAD, the phase images showed apparent phase delay in the right ventricle. In the CRBBB patients with LAD, the phase images showed many different contraction patterns varying from normal to RV phase delay, owing to the effects of the hemi-block. Quantitative analysis of the absolute values, showed that the mean (RV-LV) value was 6.6 +/- 8.4 msec in the normal subjects. In the CRBBB patients without LAD, the duration of the QRS complex correlated with the mean (RV-LV) value, whereas no difference was observed between the duration of the QRS complex and the standard deviation of the right ventricle. Using phase analysis the degree of the RBBB can be determined from the phase images, and can be quantitatively analyzed as in electrical studies.

  5. Intravenous dipyridamole thallium-201 SPECT imaging in patients with left bundle branch block

    SciTech Connect

    Rockett, J.F.; Wood, W.C.; Moinuddin, M.; Loveless, V.; Parrish, B. )

    1990-06-01

    Tl-201 exercise imaging in patients with left bundle branch block (LBBB) has proven to be indeterminate for significant left anterior descending (LAD) coronary artery stenosis because of the presence of immediate septal perfusion defects with redistribution on delayed images in almost all cases. Tl-201 redistribution occurs regardless of the presence or absence of LAD stenosis. Nineteen patients having LBBB were evaluated with dipyridamole Tl-201 SPECT. Fourteen of these subjects had normal dipyridamole Tl-201 SPECT imaging. Three patients had normal coronary angiograms. None of the remaining 11 patients with normal dipyridamole Tl-201 SPECT images was found to have clinical coronary artery disease in a 5-11 month follow-up period. Five patients had abnormal septal perfusion. Four underwent coronary angiography. One had a significant LAD stenosis. The single patient with septal redistribution who refused to undergo coronary angiography died shortly thereafter of clinical coronary artery disease. This preliminary work suggests that dipyridamole Tl-201 SPECT may be more useful for excluding LAD stenosis in patients with LBBB than Tl-201 exercise imaging.

  6. Hierarchical mordenite zeolite nano-rods bundles favourable to bulky molecules

    NASA Astrophysics Data System (ADS)

    Dai, Guang; Hao, Wenming; Xiao, Huan; Ma, Jinghong; Li, Ruifeng

    2017-10-01

    Hierarchical mordenite zeolite nano-rods bundles were successfully synthesized by a novel approach of using organosilane functioned fumed silica as silicon source. The organic moiety linked on the surface of fumed silica inhibits the growth of zeolite crystal into large size, leading to the nano-rods assembled bundles. The mordenite nanorods bundles exhibited significantly improved mesitylene adsorption capacity compared with the conventional mordenite. As a catalyst, the hierarchical mordenite nanorods bundles showed remarkable catalytic performance in the benzylation of mesitylene by benzyl chloride, due to the efficient diffusion rate and improved accessibility of the active sites in the hierarchical mordenite nanorods bundles.

  7. Nanostructured Composites: Effective Mechanical Property Determination of Nanotube Bundles

    NASA Technical Reports Server (NTRS)

    Saether, E.; Pipes, R. B.; Frankland, S. J. V.

    2002-01-01

    Carbon nanotubes naturally tend to form crystals in the form of hexagonally packed bundles or ropes that should exhibit a transversely isotropic constitutive behavior. Although the intratube axial stiffness is on the order of 1 TPa due to a strong network of delocalized bonds, the intertube cohesive strength is orders of magnitude less controlled by weak, nonbonding van der Waals interactions. An accurate determination of the effective mechanical properties of nanotube bundles is important to assess potential structural applications such as reinforcement in future composite material systems. A direct method for calculating effective material constants is developed in the present study. The Lennard-Jones potential is used to model the nonbonding cohesive forces. A complete set of transverse moduli are obtained and compared with existing data.

  8. Quantum Turbulence: Vortex Bundle Collapse and Kolmogorov Spectrum

    NASA Astrophysics Data System (ADS)

    Nemirovskii, Sergey K.

    2016-12-01

    The statement of problem is motivated by the idea of modeling the classical turbulence with a set of chaotic quantized vortex filaments in superfluids. Among various arguments supporting the idea of quasi-classic behavior of quantum turbulence, the strongest, probably, is the k dependence of the spectra of energy, E(k)∝ k^{-5/3} obtained in numerical simulations and experiments. At the same time, the mechanism of classical vs. quantum turbulence is not clarified and the source of the k^{-5/3} dependence is unclear. In this work, we concentrated on the nonuniform vortex bundles. This choice is related to the actively discussed question concerning a role of collapses in the vortex dynamics in formation of turbulent spectra. We demonstrate that the nonuniform vortex bundles, which appear in result of nonlinear vortex dynamics, generates an energy spectrum which is close to the Kolmogorov dependence ∝ k^{-5/3}.

  9. Determining impacts and factors in ventilator-associated pneumonia bundle.

    PubMed

    Rodrigues, Ana Natesia; Fragoso, Luciana Vládia E Cavalhedo; Beserra, Francisca de Melo; Ramos, Islane Costa

    2016-01-01

    Assessing the determining impacts and factors in ventilator-associated pneumonia (VAP) bundle. descriptive retrospective longitudinal study, with quantitative approach, held at a public teaching hospital. Collection held between May 2014 and April 2015. Patients of the ICU with VAP participated in the research. For organizing data, the Microsoft Excel 2010 program was used. A critical analysis between the data collected and infection rates was performed. The survey was approved under no. 566,136. an increase in the incidence of VAP after implementing the bundle was observed; the prevalent pathogens were gram-negative bacteria. Deaths were equal to or greater than 50%. Changes of professionals and lack of supplies were determining factors. in this context, the need for permanent qualification of the team is emphasized, with the purpose of promoting the adherence to the protocol and preventing VAP.

  10. Buckling of a fiber bundle embedded in epoxy

    NASA Technical Reports Server (NTRS)

    Hahn, H. T.; Sohi, M. M.

    1986-01-01

    Buckling of a fiber bundle embedded in epoxy resin was studied to gain insight into compressive failure mechanisms in unidirectional composites. The fibers used were E-glass, T300 graphite, T700 graphite, and P75 graphite. These fibers were combined with two different resins: Epon 815/V140 and Epon 828/Z. In both resins the failure mode of the bundle was found to be microbuckling of fibers for the first three types of fibers; however, the high-modulus P75 fibers failed in shear without any sign of microbuckling. The strains at which microbuckling occurred were higher than the compressive failure strains of the corresponding unidirectional composites. In the soft resin, Epon 815/V140, fibers buckled at lower strains than in the stiff resin, Epon 828/Z. The buckling strains and the segment lengths followed the trends predicted for a single filament embedded in an infinite matrix.

  11. Medical catheters thermally manipulated by fiber optic bundles

    DOEpatents

    Chastagner, P.

    1992-10-06

    A maneuverable medical catheter comprising a flexible tube having a functional tip is described. The catheter is connected to a control source. The functional tip of the catheter carries a plurality of temperature activated elements arranged in parallel and disposed about the functional tip and held in spaced relation at each end. These elements expand when they are heated. A plurality of fiber optic bundles, each bundle having a proximal end attached to the control source and a distal end attached to one of the elements carry light into the elements where the light is absorbed as heat. By varying the optic fiber that is carrying the light and the intensity of the light, the bending of the elements can be controlled and thus the catheter steered. In an alternate embodiment, the catheter carries a medical instrument for gathering a sample of tissue. The instrument may also be deployed and operated by thermal expansion and contraction of its moving parts. 10 figs.

  12. Medical catheters thermally manipulated by fiber optic bundles

    DOEpatents

    Chastagner, Philippe

    1992-01-01

    A maneuverable medical catheter comprising a flexible tube having a functional tip. The catheter is connected to a control source. The functional tip of the catheter carries a plurality of temperature activated elements arranged in parallel and disposed about the functional tip and held in spaced relation at each end. These elements expand when they are heated. A plurality of fiber optic bundles, each bundle having a proximal end attached to the control source and a distal end attached to one of the elements carry light into the elements where the light is absorbed as heat. By varying the optic fiber that is carrying the light and the intensity of the light, the bending of the elements can be controlled and thus the catheter steered. In an alternate embodiment, the catheter carries a medical instrument for gathering a sample of tissue. The instrument may also be deployed and operated by thermal expansion and contraction of its moving parts.

  13. Synthesis of bundled tungsten oxide nanowires with controllable morphology

    SciTech Connect

    Sun Shibin Zou Zengda; Min Guanghui

    2009-05-15

    Bundled tungsten oxide nanowires with controllable morphology were synthesized by a simple solvothermal method with tungsten hexachloride (WCl{sub 6}) as precursor and cyclohexanol as solvent. The as-synthesized products were systematically characterized by using scanning electron microscopy, X-ray diffraction and transition electron microscopy. Brunauer-Emmett-Teller gas-sorption measurements were also employed. Accompanied by an apparent drop of specific surface area from 151 m{sup 2} g{sup -1} for the longer nanowires synthesized using a lower concentration of WCl{sub 6} to 106 m{sup 2} g{sup -1} for the shorter nanowires synthesized using a higher concentration of WCl{sub 6}, a dramatically morphological evolution was also observed. With increasing concentration of tungsten hexachloride (WCl{sub 6}) in cyclohexanol, the nanostructured bundles became larger, shorter and straighter, and finally a block-shape product occurred.

  14. Bundle adjustment with raw inertial observations in UAV applications

    NASA Astrophysics Data System (ADS)

    Cucci, Davide Antonio; Rehak, Martin; Skaloud, Jan

    2017-08-01

    It is well known that accurate aerial position and attitude control is beneficial for image orientation in airborne photogrammetry. The aerial control is traditionally obtained by Kalman filtering/smoothing inertial and GNSS observations prior to the bundle-adjustment. However, in Micro Aerial Vehicles this process may result in poor attitude determination due to the limited quality of the inertial sensors, large alignment uncertainty and residual correlations between sensor biases and initial attitude. We propose to include the raw inertial observations directly into the bundle-adjustment instead of as position and attitude weighted observations from a separate inertial/GNSS fusion step. The necessary observation models are derived in detail within the context of the so called ;Dynamic Networks;. We examine different real world cases and we show that the proposed approach is superior to the established processing pipeline in challenging scenarios such as mapping in corridors and in areas where the reception of GNSS signals is denied.

  15. Bundled multi-tube nozzle for a turbomachine

    DOEpatents

    Lacy, Benjamin Paul; Ziminsky, Willy Steve; Johnson, Thomas Edward; Zuo, Baifang; York, William David; Uhm, Jong Ho

    2015-09-22

    A turbomachine includes a compressor, a combustor operatively connected to the compressor, an end cover mounted to the combustor, and an injection nozzle assembly operatively connected to the combustor. The injection nozzle assembly includes a cap member having a first surface that extends to a second surface. The cap member further includes a plurality of openings. A plurality of bundled mini-tube assemblies are detachably mounted in the plurality of openings in the cap member. Each of the plurality of bundled mini-tube assemblies includes a main body section having a first end section and a second end section. A fluid plenum is arranged within the main body section. A plurality of tubes extend between the first and second end sections. Each of the plurality of tubes is fluidly connected to the fluid plenum.

  16. Curved Space-Times by Crystallization of Liquid Fiber Bundles

    NASA Astrophysics Data System (ADS)

    Hélein, Frédéric; Vey, Dimitri

    2017-01-01

    Motivated by the search for a Hamiltonian formulation of Einstein equations of gravity which depends in a minimal way on choices of coordinates, nor on a choice of gauge, we develop a multisymplectic formulation on the total space of the principal bundle of orthonormal frames on the 4-dimensional space-time. This leads quite naturally to a new theory which takes place on 10-dimensional manifolds. The fields are pairs of ((α ,ω ),π), where (α ,ω ) is a 1-form with coefficients in the Lie algebra of the Poincaré group and π is an 8-form with coefficients in the dual of this Lie algebra. The dynamical equations derive from a simple variational principle and imply that the 10-dimensional manifold looks locally like the total space of a fiber bundle over a 4-dimensional base manifold. Moreover this base manifold inherits a metric and a connection which are solutions of a system of Einstein-Cartan equations.

  17. Dimer model for Tau proteins bound in microtubule bundles

    NASA Astrophysics Data System (ADS)

    Hall, Natalie; Kluber, Alexander; Hayre, N. Robert; Singh, Rajiv; Cox, Daniel

    2013-03-01

    The microtubule associated protein tau is important in nucleating and maintaining microtubule spacing and structure in neuronal axons. Modification of tau is implicated as a later stage process in Alzheimer's disease, but little is known about the structure of tau in microtubule bundles. We present preliminary work on a proposed model for tau dimers in microtubule bundles (dimers are the minimal units since there is one microtubule binding domain per tau). First, a model of tau monomer was created and its characteristics explored using implicit solvent molecular dynamics simulation. Multiple simulations yield a partially collapsed form with separate positively/negatively charged clumps, but which are a factor of two smaller than required by observed microtubule spacing. We argue that this will elongate in dimer form to lower electrostatic energy at a cost of entropic ``spring'' energy. We will present preliminary results on steered molecular dynamics runs on tau dimers to estimate the actual force constant. Supported by US NSF Grant DMR 1207624.

  18. Computing exact bundle compliance control charts via probability generating functions.

    PubMed

    Chen, Binchao; Matis, Timothy; Benneyan, James

    2016-06-01

    Compliance to evidenced-base practices, individually and in 'bundles', remains an important focus of healthcare quality improvement for many clinical conditions. The exact probability distribution of composite bundle compliance measures used to develop corresponding control charts and other statistical tests is based on a fairly large convolution whose direct calculation can be computationally prohibitive. Various series expansions and other approximation approaches have been proposed, each with computational and accuracy tradeoffs, especially in the tails. This same probability distribution also arises in other important healthcare applications, such as for risk-adjusted outcomes and bed demand prediction, with the same computational difficulties. As an alternative, we use probability generating functions to rapidly obtain exact results and illustrate the improved accuracy and detection over other methods. Numerical testing across a wide range of applications demonstrates the computational efficiency and accuracy of this approach.

  19. CAT reconstruction and potting comparison of a LMFBR fuel bundle

    SciTech Connect

    Betten, P.R.; Tow, D.M.

    1984-04-01

    A standard Liquid Metal Fast Breeder Reactor (LMFBR) subassembly used in the Experimental Breeder Reactor II (EBR-II) was investigated, by remote techniques, for fuel bundle</