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Sample records for relaxing incision knife

  1. Effect of blade configuration, knife action, and intraocular pressure on keratotomy incision depth and shape.

    PubMed

    Melles, G R; Wijdh, R H; Cost, B; Beekhuis, W H; Binder, P S; van Rij, G; Groot, K

    1993-07-01

    For the same diamond blade extension, uphill (centripetal) radial keratotomy incision direction achieves greater depth and consequently greater refractive effect than downhill (centrifugal) incisions. To determine which factors may account for this difference, two uphill and two downhill incisions were made with a double-edged diamond blade set to 90% central pachometry in 26 human donor eyes at 15 or 60 mm Hg. Uphill incisions made with the perpendicular blade had greater mean incision depth than downhill incisions made with the oblique blade at 15 mm Hg (83.6 +/- 3.9% and 68.2 +/- 5.2%) (p < 0.0005) and at 60 mm Hg (86.3 +/- 3.1% and 79.7 +/- 1.7%) (p < 0.0005). Uphill and downhill incisions both made with the perpendicular blade had equal depth (85.4 +/- 4.9% and 83.7 +/- 3.5%) (p > 0.1). The perpendicular blade edge created a straight, and the oblique edge an S- or J-shaped, histological incision configuration. Corneal profile pictures taken during each incision showed the knife to tilt opposite of the incision direction and to move at a constant angle to the limbal plane, producing a smaller optical clear zone (OCZ) in the posterior stroma than intended with uphill incisions. Greater refractive effect with uphill incisions may be explained by the perpendicular blade being more effective in incising corneal lamellae, and the creation of a smaller posterior OCZ. Intraocular pressure variations during surgery may affect achieved incision depth of downhill, but not of uphill, incisions. PMID:8339558

  2. A case of endophthalmitis associated with limbal relaxing incision

    PubMed Central

    Haripriya, Aravind; Syeda, Taranum S

    2012-01-01

    Limbal relaxing incisions (LRIs) are considered a relatively safe procedure with rapid stabilization and absence of infectious complications. Do we need to readdress this last impression? We report a case of nocardia endophthalmitis associated with an exudate at the site of an LRI in a patient who underwent routine cataract surgery. This case, to the best of our knowledge, is the first report of its kind, stressing the need for a cautious approach to the adoption of this method of astigmatic correction. PMID:22569388

  3. A stab in the dark: Design and construction of a novel device for conducting incised knife trauma investigations and its initial test.

    PubMed

    Humphrey, Caitlin; Kumaratilake, Jaliya; Henneberg, Maciej

    2016-05-01

    Knife attacks are commonly seen in Australia and other countries. During forensic investigations the force with which a wound was inflicted is often questioned. The ability to examine resultant trauma and particular weapons at different forces with an experimental device may lead to better interpretations of knife wounds. The objective of this study is to design, construct and test a device to analyse the characteristics and forces involved in knife attacks, particularly incised wounds. The mechanical variables (e.g. force, angle, knife geometry) involved in knife attacks have been considered to design and construct a suitable device which allows these variables to be systematically controlled and varied. A device was designed and constructed from mild steel. This included a pivoting arm and instrumented knife holder. The arm has adjustable angle and weight so that knives can be operated at different calculated forces. A device was successfully constructed and the repeatability of incised knife trauma and its characteristics in skeletal tissues were investigated. A device which allows reproducible and controlled experiments with knife wounds will be advantageous to forensic investigations. In particular, in determining forces and types of weapons associated with particular wounds, identifying or eliminating suspected weapons and more accurately answering the common question: How much force would be required to cause that particular wound. This could help to characterise the perpetrator. The device can be altered to be used in the future to investigate trauma caused by other weapons. PMID:27061866

  4. Factors Influencing Efficacy of Peripheral Corneal Relaxing Incisions during Cataract Surgery

    PubMed Central

    Hirnschall, Nino; Wiesinger, Jörg; Draschl, Petra; Findl, Oliver

    2015-01-01

    Purpose. To evaluate influencing factors on the residual astigmatism after performing peripheral corneal relaxing incisions (PCRIs) during cataract surgery. Methods. This prospective study included patients who were scheduled for cataract surgery with PCRIs. Optical biometry (IOLMaster 500, Carl Zeiss Meditec AG, Germany) was taken preoperatively, 1 week, 4 months, and 1 year postoperatively. Additionally, corneal topography (Atlas model 9000, Carl Zeiss Meditec AG, Germany), ORA (Ocular Response Analyzer, Reichert Ophthalmic Instruments, USA), and autorefraction (Autorefractometer RM 8800 Topcon) were performed postoperatively. Results. Mean age of the study population (n = 74) was 73.5 years (±9.3; range: 53 to 90) and mean corneal astigmatism preoperatively was −1.82 D (±0.59; 1.00 to 4.50). Mean corneal astigmatism was reduced to 1.14 D (±0.67; 0.11 to 3.89) 4 months postoperatively. A partial least squares regression showed that a high eccentricity of the cornea, a large deviation between keratometry and topography, and a high preoperative astigmatism resulted in a larger postoperative error concerning astigmatism. Conclusions. PCRI causes a reduction of preoperative astigmatism, though the prediction is difficult but several factors were found to be a relevant source of error. PMID:26199739

  5. Long-term outcomes of limbal relaxing incisions during cataract surgery: aberrometric analysis

    PubMed Central

    Monaco, Gaspare; Scialdone, Antonio

    2015-01-01

    Purpose To compare the final changes in corneal wavefront aberration by limbal relaxing incisions (LRIs) after cataract surgery. Methods This prospective cumulative interventional nonrandomized case study included cataract and astigmatic patients undergoing LRIs and phaco with intraocular lens implantation. LRIs were planned using Donnenfeld nomogram. The root mean square of corneal wave aberration for total Z(n,i)(1≤n≤8), astigmatism Z(2,±1), coma Z(3–5–7,±1), trefoil Z(3–5–7,±2), spherical Z(4–6–8,0), and higher-order aberration (HOA) Z(3≤n≤8) was examined before and 3 years after surgery (optical path difference-Scan II [OPD-Scan II)]. Uncorrected distance visual acuity and best-corrected distance visual acuity (CDVA) for distance, keratometric cylinder, and variations in average corneal power were also analyzed. Results Sixty-four eyes of 48 patients were included in the study. Age ranged from 42 to 92 years (70.6±8.4 years). After LRIs, uncorrected distance visual acuity and best-corrected distance visual acuity improved statistically (P<0.01). The keratometric cylinder value decreased by 40.1%, but analysis of KP90 and KP135 polar values did not show any decrease that could be statistically confirmed (P=0.22 and P=0.24). No significant changes were detected in root mean square of total (P=0.61) and HOAs (P=0.13) aberrations. LRIs did not induce alteration in central corneal power confirming a 1:1 coupling ratio. Conclusion LRIs determined a nonsignificant alteration of corneal HOA. Therefore, LRIs can be still considered a qualitatively viable mean in those cases where toric intraocular lenses are contraindicated or not available. Yet, the authors raise the question of nonpersonalized nomograms, as in the present study, LRIs did not reach the preset target cylinder. PMID:26357459

  6. Dosimetric and radiobiological comparison of CyberKnife M6™ InCise multileaf collimator over IRIS™ variable collimator in prostate stereotactic body radiation therapy

    PubMed Central

    Kathriarachchi, Vindu; Shang, Charles; Evans, Grant; Leventouri, Theodora; Kalantzis, Georgios

    2016-01-01

    The impetus behind our study was to establish a quantitative comparison between the IRIS collimator and the InCise multileaf collimator (MLC) (Accuray Inc. Synnyvale, CA) for prostate stereotactic body radiation therapy (SBRT). Treatment plans for ten prostate cancer patients were performed on MultiPlan™ 5.1.2 treatment planning system utilizing MLC and IRIS for 36.25 Gy in five fractions. To reduce the magnitude of variations between cases, the planning tumor volume (PTV) was defined and outlined for treating prostate gland only, assuming no seminal vesicle or ex-capsule involvement. Evaluation indices of each plan include PTV coverage, conformity index (CI), Paddick's new CI, homogeneity index, and gradient index. Organ at risk (OAR) dose sparing was analyzed by the bladder wall Dmax and V37Gy, rectum Dmax and V36Gy. The radiobiological response was evaluated by tumor control probability and normal tissue complication probability based on equivalent uniform dose. The dose delivery efficiency was evaluated on the basis of planned monitor units (MUs) and the reported treatment time per fraction. Statistical significance was tested using the Wilcoxon signed rank test. The studies indicated that CyberKnife M6™ IRIS and InCise™ MLC produce equivalent SBRT prostate treatment plans in terms of dosimetry, radiobiology, and OAR sparing, except that the MLC plans offer improvement of the dose fall-off gradient by 29% over IRIS. The main advantage of replacing the IRIS collimator with MLC is the improved efficiency, determined from the reduction of MUs by 42%, and a 36% faster delivery time. PMID:27217626

  7. Dosimetric and radiobiological comparison of CyberKnife M6™ InCise multileaf collimator over IRIS™ variable collimator in prostate stereotactic body radiation therapy.

    PubMed

    Kathriarachchi, Vindu; Shang, Charles; Evans, Grant; Leventouri, Theodora; Kalantzis, Georgios

    2016-01-01

    The impetus behind our study was to establish a quantitative comparison between the IRIS collimator and the InCise multileaf collimator (MLC) (Accuray Inc. Synnyvale, CA) for prostate stereotactic body radiation therapy (SBRT). Treatment plans for ten prostate cancer patients were performed on MultiPlan™ 5.1.2 treatment planning system utilizing MLC and IRIS for 36.25 Gy in five fractions. To reduce the magnitude of variations between cases, the planning tumor volume (PTV) was defined and outlined for treating prostate gland only, assuming no seminal vesicle or ex-capsule involvement. Evaluation indices of each plan include PTV coverage, conformity index (CI), Paddick's new CI, homogeneity index, and gradient index. Organ at risk (OAR) dose sparing was analyzed by the bladder wall Dmax and V37Gy, rectum Dmax and V36Gy. The radiobiological response was evaluated by tumor control probability and normal tissue complication probability based on equivalent uniform dose. The dose delivery efficiency was evaluated on the basis of planned monitor units (MUs) and the reported treatment time per fraction. Statistical significance was tested using the Wilcoxon signed rank test. The studies indicated that CyberKnife M6™ IRIS and InCise™ MLC produce equivalent SBRT prostate treatment plans in terms of dosimetry, radiobiology, and OAR sparing, except that the MLC plans offer improvement of the dose fall-off gradient by 29% over IRIS. The main advantage of replacing the IRIS collimator with MLC is the improved efficiency, determined from the reduction of MUs by 42%, and a 36% faster delivery time. PMID:27217626

  8. A Hot Knife Through Ice-Cream: Earthflow Response to Channel Incision (Or Channel Response to Earthflows?), Eel River Canyon, California

    NASA Astrophysics Data System (ADS)

    Mackey, B. H.; Roering, J. J.; McKean, J. A.

    2007-12-01

    Abundant glacier-like earthflow features are recognized as a primary erosional process in the highly erodable Franciscan Melange of the Eel River Basin, CA. Despite their prominence in this "melting ice-cream" topography, many questions regarding their effects on the long term sediment flux from this rapidly eroding basin remain unresolved. For example, does an earthflow's basal shear zone propagate vertically downwards with vertical river incision? What controls the upslope and lateral extent of individual earthflows? How does the erosive power of a river influence the rate of earthflow movement, or conversely do earthflow toe deposits regulate the rate of river incision? Here we present preliminary findings derived from study of 200km2 of lidar data (1m resolution) covering hillslopes adjacent to 30km of the Eel River. Lidar allows detailed analysis of the interaction between earthflows and the drainage network, and we document how inferred changes in local base level are propagated throughout adjacent hillslopes via earthflow movement. The most active earthflows (determined by field surveying and analysis of aerial photos rectified using lidar- generated digital topography) coincide with locally steep sections of channel, while downstream of the most active flows we frequently observe less-active or dormant earthflows. This observation supports the idea that the locations of the most active earthflows coincide with headward propagating knickpoints in the channel. The rate of earthflow movement appears to slow when an earthflow exhausts the upslope area of easily mobilized sediment. Earthflow toes can protrude directly into the channel, causing the channel to narrow and steepen, and even undercut the opposite bank. Large resistant boulders (>2m diameter) transported by the earthflow accumulate in the streambed and appear to both act as a check on further channel incision and earthflow movement. In contrast, areas adjacent to active earthflows exhibit smooth

  9. Use of a Toric Intraocular Lens and a Limbal-Relaxing Incision for the Management of Astigmatism in Combined Glaucoma and Cataract Surgery

    PubMed Central

    Gibbons, Allister

    2016-01-01

    Purpose We report the surgical management of a patient with glaucoma undergoing cataract surgery with high preexisting astigmatism. A combination of techniques was employed for her astigmatism management. Methods A 76-year-old female with 5.5 dpt of corneal astigmatism underwent surgery in her left eye consisting of one-site trabeculectomy, phacoemulsification, toric intraocular lens implantation and a single inferior limbal-relaxing incision. Results Intraocular pressure control was achieved with no medication at 11 mm Hg; before the filtering procedure, the pressure was 16 mm Hg on two topical drugs. Astigmatism was reduced to 0.75 dpt, and both corrected and uncorrected visual acuity improved. Conclusions Astigmatism management can have a good outcome in combined procedures. We encourage surgeons to address astigmatism in the preoperative planning of patients undergoing glaucoma surgery associated with phacoemulsification. PMID:27293408

  10. Bipolar plasma vaporization using plasma-cutting and plasma-loop electrodes versus cold-knife transurethral incision for the treatment of posterior urethral stricture: a prospective, randomized study

    PubMed Central

    Cai, Wansong; Chen, Zhiyuan; Wen, Liping; Jiang, Xiangxin; Liu, Xiuheng

    2016-01-01

    OBJECTIVE: Evaluate the efficiency and safety of bipolar plasma vaporization using plasma-cutting and plasma-loop electrodes for the treatment of posterior urethral stricture. Compare the outcomes following bipolar plasma vaporization with conventional cold-knife urethrotomy. METHODS: A randomized trial was performed to compare patient outcomes from the bipolar and cold-knife groups. All patients were assessed at 6 and 12 months postoperatively via urethrography and uroflowmetry. At the end of the first postoperative year, ureteroscopy was performed to evaluate the efficacy of the procedure. The mean follow-up time was 13.9 months (range: 12 to 21 months). If re-stenosis was not identified by both urethrography and ureteroscopy, the procedure was considered “successful”. RESULTS: Fifty-three male patients with posterior urethral strictures were selected and randomly divided into two groups: bipolar group (n=27) or cold-knife group (n=26). Patients in the bipolar group experienced a shorter operative time compared to the cold-knife group (23.45±7.64 hours vs 33.45±5.45 hours, respectively). The 12-month postoperative Qmax was faster in the bipolar group than in the cold-knife group (15.54±2.78 ml/sec vs 18.25±2.12 ml/sec, respectively). In the bipolar group, the recurrence-free rate was 81.5% at a mean follow-up time of 13.9 months. In the cold-knife group, the recurrence-free rate was 53.8%. CONCLUSIONS: The application of bipolar plasma-cutting and plasma-loop electrodes for the management of urethral stricture disease is a safe and reliable method that minimizes the morbidity of urethral stricture resection. The advantages include a lower recurrence rate and shorter operative time compared to the cold-knife technique. PMID:26872076

  11. Gamma Knife

    MedlinePlus

    ... results are sent to the Gamma Knife®'s planning computer system. Together, physicians ( radiation oncologists and neurosurgeons) and medical physicists delineate targets and normal anatomical structures. They use a planning computer program to determine the exact spatial relationship between ...

  12. Cold knife cone biopsy

    MedlinePlus

    A cold knife cone biopsy (conization) is surgery to remove a sample of abnormal tissue from the cervix. The ... Cold knife cone biopsy is done to detect cervical cancer or early changes that lead to cancer. ...

  13. Cold knife cone biopsy

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003910.htm Cold knife cone biopsy To use the sharing features on this page, please enable JavaScript. A cold knife cone biopsy (conization) is surgery to remove ...

  14. Incising Tibet

    NASA Astrophysics Data System (ADS)

    Yang, R.; Herman, F.; Fellin, M. G.; Willett, S.; Wang, W.

    2014-12-01

    Convergence between India and Eurasia has produced the Tibetan Plateau, which stands 5 km high over a region of 3 million km2,since collision at ~50 Ma. A key region for understanding the mechanisms and timing of uplift is the SE margin, where major rivers have incised the plateau margin, permitting the use of thermochronometry to time incision. Here we present new (U-Th)/He ages including 17 ages on apatite and 23 on zircon and 12 apatite fission track ages on the southeastern margins of the Plateau to explore rates and timing of incision. All three thermochronometric systems on the Salween suggest a regional change in the last 8 Myr and exhibit progressive younging over ~ 150 km upstream. Apatite (U-Th)/He ages of valley bottom samples from the Mekong become younger upstream whereas apatite fission-track and zircon (U-Th)/He ages show a large scatter from ~ 5 Ma to ~160 Ma, depending on the distance above the thalweg. Similarly, upstream samples north of 290N on the Yangtze yield much younger ages than downstream samples. Inversion of combined thermochronometers reveals a northward propagation of the highest rates of incision along the Salween and Mekong since 8 Ma. These results, together with analysis of river profiles, are best explained by a scenario of plateau incision that occurred in southeastern Tibet before or coeval at 8 Ma. We infer that the southeastern plateau margin was deformed under a complex context with both lateral expansion of the plateau margin and oblique indenting of the India plate localizing shortening and high uplift rates at the corner of the indenter.

  15. The Shoemaker's Knife

    ERIC Educational Resources Information Center

    Thomson, Ian

    2010-01-01

    Archimedes, the famous Greek mathematician, lived from 287 BCE until approximately 212 BCE. He thought that the figure of two semi-circles on a straight line enclosed by a larger semi-circle resembled a shoemaker's knife. Archimedes called this figure an "arbelos" since arbelos is the Greek word for a shoemaker's knife. The author describes the…

  16. Dynamic gamma knife radiosurgery

    NASA Astrophysics Data System (ADS)

    Luan, Shuang; Swanson, Nathan; Chen, Zhe; Ma, Lijun

    2009-03-01

    Gamma knife has been the treatment of choice for various brain tumors and functional disorders. Current gamma knife radiosurgery is planned in a 'ball-packing' approach and delivered in a 'step-and-shoot' manner, i.e. it aims to 'pack' the different sized spherical high-dose volumes (called 'shots') into a tumor volume. We have developed a dynamic scheme for gamma knife radiosurgery based on the concept of 'dose-painting' to take advantage of the new robotic patient positioning system on the latest Gamma Knife C™ and Perfexion™ units. In our scheme, the spherical high dose volume created by the gamma knife unit will be viewed as a 3D spherical 'paintbrush', and treatment planning reduces to finding the best route of this 'paintbrush' to 'paint' a 3D tumor volume. Under our dose-painting concept, gamma knife radiosurgery becomes dynamic, where the patient moves continuously under the robotic positioning system. We have implemented a fully automatic dynamic gamma knife radiosurgery treatment planning system, where the inverse planning problem is solved as a traveling salesman problem combined with constrained least-square optimizations. We have also carried out experimental studies of dynamic gamma knife radiosurgery and showed the following. (1) Dynamic gamma knife radiosurgery is ideally suited for fully automatic inverse planning, where high quality radiosurgery plans can be obtained in minutes of computation. (2) Dynamic radiosurgery plans are more conformal than step-and-shoot plans and can maintain a steep dose gradient (around 13% per mm) between the target tumor volume and the surrounding critical structures. (3) It is possible to prescribe multiple isodose lines with dynamic gamma knife radiosurgery, so that the treatment can cover the periphery of the target volume while escalating the dose for high tumor burden regions. (4) With dynamic gamma knife radiosurgery, one can obtain a family of plans representing a tradeoff between the delivery time and the

  17. Pleuroscopic punch biopsy using insulated-tip diathermic knife-2 for the diagnosis of desmoplastic malignant mesothelioma.

    PubMed

    Masai, Kyohei; Sasada, Shinji; Izumo, Takehiro; Taniyama, Tomoko; Nakamura, Yukiko; Chavez, Christine; Sakurai, Hiroyuki; Tsuta, Koji; Tsuchida, Takaaki

    2013-10-01

    Desmoplastic malignant mesothelioma (DMM) is a rare subtype of malignant pleural mesothelioma (MPM) and is often difficult to distinguish from pleural fibrosis and reactive mesothelial hyperplasia, especially if the biopsy samples are small. We performed full-thickness pleural biopsy on a lesion suspected to be DMM using an insulated-tip diathermic knife-2 (IT knife-2) during flex-rigid pleuroscopy. IT knife-2 is a novel electrosurgical device for endoscopic submucosal dissection in the early gastrointestinal cancer. It consists of a needle knife with 3 short blades at the distal end attached to an insulated ceramic tip. A 54-year-old man presenting with chest wall mass and thickened pleura, in whom a computed tomography-guided percutaneous needle aspiration had remained negative, underwent flex-rigid pleuroscopy for definitive diagnosis. While applying electric current, we used the IT knife-2 to incise the pleura in a circular shape just above the endothoracic fascia. The incised pleura was removed by forceps and examined pathologically. The microscopic examination was compatible with DMM. We discovered that pleuroscopic punch biopsy using IT knife-2 can diagnose DMM. Use of IT knife-2 during flex-rigid pleuroscopy can obtain sufficient samples from densely thickened pleura, which is difficult to diagnose with small biopsies. PMID:24162121

  18. The Knife Machine. Module 15.

    ERIC Educational Resources Information Center

    South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

    This module on the knife machine, one in a series dealing with industrial sewing machines, their attachments, and operation, covers one topic: performing special operations on the knife machine (a single needle or multi-needle machine which sews and cuts at the same time). These components are provided: an introduction, directions, an objective,…

  19. Stereotactic radiosurgery - CyberKnife

    MedlinePlus

    ... slides into a machine that delivers radiation. A robotic arm controlled by a computer moves around you. ... Accuray Incorporated. CyberKnife robotic radiosurgery system patient brochure. 2012. ... Accessed ...

  20. High grade anorectal stricture complicating Crohn's disease: endoscopic treatment using insulated-tip knife

    PubMed Central

    Chon, Hyung Ku; Shin, Ik Sang; Kim, Sang Wook

    2016-01-01

    Endoscopic treatments have emerged as an alternative to surgery, in the treatment of benign colorectal stricture. Unlike endoscopic balloon dilatation, there is limited data on endoscopic electrocautery incision therapy for benign colorectal stricture, especially with regards to safety and long-term patency. We present a case of a 29-year-old female with Crohn's disease who had difficulty in defecation and passing thin stools. A pelvic magnetic resonance imaging scan, gastrograffin enema, and sigmoidoscopy showed a high-grade anorectal stricture. An endoscopic insulated-tip knife incision was successfully performed to resolve the problem. From our experience, we suggest that endoscopic insulated-tip knife treatment may be a feasible and effective modality for patients with short-segment, very rigid, fibrotic anorectal stricture. PMID:27433152

  1. High grade anorectal stricture complicating Crohn's disease: endoscopic treatment using insulated-tip knife.

    PubMed

    Chon, Hyung Ku; Shin, Ik Sang; Kim, Sang Wook; Lee, Soo Teik

    2016-07-01

    Endoscopic treatments have emerged as an alternative to surgery, in the treatment of benign colorectal stricture. Unlike endoscopic balloon dilatation, there is limited data on endoscopic electrocautery incision therapy for benign colorectal stricture, especially with regards to safety and long-term patency. We present a case of a 29-year-old female with Crohn's disease who had difficulty in defecation and passing thin stools. A pelvic magnetic resonance imaging scan, gastrograffin enema, and sigmoidoscopy showed a high-grade anorectal stricture. An endoscopic insulated-tip knife incision was successfully performed to resolve the problem. From our experience, we suggest that endoscopic insulated-tip knife treatment may be a feasible and effective modality for patients with short-segment, very rigid, fibrotic anorectal stricture. PMID:27433152

  2. J incision in neck dissections.

    PubMed

    Acar, A; Dursun, G; Aydin, O; Akbaş, Y

    1998-01-01

    Metastasis in the neck lymph system of primary tumours of the head and neck is frequently seen. In order to prevent this metastasis, neck dissection is carried out by various types of skin incisions. In this study, types of skin incision used in neck dissections were defined, and the advantages, disadvantages and results of J incisions, which have been performed on 320 radical neck dissection patients in our clinic between 1985-1996, were compared with those of other incision types. PMID:9538447

  3. Intralesional Injection of Mitomycin C at Transurethral Incision of Bladder Neck Contracture May Offer Limited Benefit: TURNS Study Group

    PubMed Central

    Redshaw, Jeffrey D.; Broghammer, Joshua A.; Smith, Thomas G.; Voelzke, Bryan B.; Erickson, Bradley A.; McClung, Christopher D.; Elliott, Sean P.; Alsikafi, Nejd F.; Presson, Angela P.; Aberger, Michael E.; Craig, James R.; Brant, William O.; Myers, Jeremy B.

    2015-01-01

    Purpose Injection of mitomycin C may increase the success of transurethral incision of the bladder neck for the treatment of bladder neck contracture. We evaluated the efficacy of mitomycin C injection across multiple institutions. Materials and Methods Data on all patients who underwent transurethral incision of the bladder neck with mitomycin C from 2009 to 2014 were retrospectively reviewed from 6 centers in the TURNS. Patients with at least 3 months of cystoscopic followup were included in the analysis. Results A total of 66 patients underwent transurethral incision of the bladder neck with mitomycin C and 55 meeting the study inclusion criteria were analyzed. Mean ± SD patient age was 64 ± 7.6 years. Dilation or prior transurethral incision of the bladder neck failed in 80% (44 of 55) of patients. Overall 58% (32 of 55) of patients achieved resolution of bladder neck contracture after 1 transurethral incision of the bladder neck with mitomycin C at a median followup of 9.2 months (IQR 11.7). There were 23 patients who had recurrence at a median of 3.7 months (IQR 4.2), 15 who underwent repeat transurethral incision of the bladder neck with mitomycin C and 9 of 15 (60%) who were free of another recurrence at a median of 8.6 months (IQR 8.8), for an overall success rate of 75% (41 of 55). Incision with electrocautery (Collins knife) was predictive of success compared with cold knife incision (63% vs 50%, p=0.03). Four patients experienced serious adverse events related to mitomycin C and 3 needed or are planning cystectomy. Conclusions The efficacy of intralesional injection of mitomycin C at transurethral incision of the bladder neck was lower than previously reported and was associated with a 7% rate of serious adverse events. PMID:25200807

  4. Longitudinal relationship between incisal occlusion and incisal tooth wear.

    PubMed

    Silness, J; Johannessen, G; Røynstrand, T

    1993-02-01

    The purpose of the study was to evaluate the longitudinal relationship between incisal wear of central incisors and the size of vertical overbite (OB) and horizontal overjet (OJ). Stone casts of 51 subjects were used for the determinations. Casts were obtained when the subjects were 15 and 27 years old. Statistical analysis was performed with the t test for paired samples, the chi-square test of association. Pearson's product moment correlation coefficient, and Spearman's rank correlation coefficient. Both overbite and overjet diminished after 12 years, and incisal wear increased. It was concluded that increase in age, incisal wear, vertical overbite and incisal occlusion (OB/OJ) are clinical predictors of wear of maxillary and mandibular central incisors in adolescents. PMID:8451919

  5. Maintaining knife sharpness in industrial meat cutting: A matter of knife or meat cutter ability.

    PubMed

    Karltun, J; Vogel, K; Bergstrand, M; Eklund, J

    2016-09-01

    Knife sharpness is imperative in meat cutting. The aim of this study was to compare the impact of knife blade steel quality with meat cutters' individual ability to maintain the cutting edge sharp in an industrial production setting. Twelve meat cutters in two different companies using three different knives during normal production were studied in this quasi-experimental study. Methods included were measuring knife cutting force before and after knife use, time knives were used, ratings of sharpness and discomfort and interviews. Results showed that the meat cutters' skill of maintaining sharpness during work had a much larger effect on knife sharpness during work than the knife steel differences. The ability was also related to feelings of discomfort and to physical exertion. It was found that meat cutters using more knives were more likely to suffer from discomfort in the upper limbs, which is a risk for developing MSD. PMID:27184316

  6. A sharp knife for high temperatures

    NASA Technical Reports Server (NTRS)

    Heisman, R. M.; Iceland, W. F.

    1978-01-01

    Electrically heated nickel-chrome-steel alloy knife may be used to cut heat resistant plastic felt and similar materials with relative ease. Blade made of commercially available alloy RA 330 retains edge at temperatures as high as 927 C.

  7. Incisal orientation and biting efficiency.

    PubMed

    Ang, K Y; Lucas, Peter W; Tan, H T W

    2006-06-01

    Broad-edged 'spatulate' upper and lower incisors are distinctive of catarrhines and platyrrhines who use them in various ways to peel fruits, remove bark, and strip leaves from branches. The incisors of modern humans not only control the bite size of foods during ingestion, but often grip items in a number of non-food related tasks. Such uses have long been implicated for Neandertals as well. Despite the evolutionary importance of incision and the fact that the incisors feature prominently in clinical dentistry (via orthodontic practices designed both to correct incisal misalignments and adjust their orientation), little is known about what affects their functional efficiency. Few mechanical analyses of incisal action have been published and none that seem to take note of the mechanisms of both fracture and friction at the tooth-food interface. Here, we modeled the incisal tip as a wedge, finding that the efficiency of biting foods that fracture elastically is strongly dependent on both the apex angle of the incisor and the coefficient of friction. Based on apex angle measurements from a small sample of human central incisors, the overall efficiency of upper central incisors is predicted to be greatest when the angle between the apex bisector and the direction of applied force is zero. However, this is complicated greatly by friction, particularly for the lower incisors. The analysis probably applies not only to the use of incisors by humans, but also to some extent to frugivorous primates. This model should clarify the mechanics behind incision and can provide a basic foundation upon which more advanced models can be built on in the future. PMID:16530808

  8. Postoperative Granulomas at Liposuction Incision Sites.

    PubMed

    Weniger, Frederick G; White, Peter F; Barrero Castedo, Carlos E

    2016-02-01

    Since most liposuction incisions heal uneventfully, difficult healing in such incisions must be investigated. In the cases of two gynecomastia liposuction patients in which a water-based lubricating gel was used on the liposuction incisions, the incisions failed to heal. For both patients, workup uncovered palisading granulomas at the lateral inframammary fold incision sites several months after otherwise successful surgeries. These two cases are presented and the previous literature is reviewed, with consideration given to the etiology and prevention of such granulomas. LEVEL OF EVIDENCE 5: Risk. PMID:26647136

  9. 21 CFR 886.4230 - Ophthalmic knife test drum.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ophthalmic knife test drum. 886.4230 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4230 Ophthalmic knife test drum. (a) Identification. An ophthalmic knife test drum is a device intended to test the keenness of ophthalmic...

  10. 21 CFR 886.4230 - Ophthalmic knife test drum.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ophthalmic knife test drum. 886.4230 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4230 Ophthalmic knife test drum. (a) Identification. An ophthalmic knife test drum is a device intended to test the keenness of ophthalmic...

  11. 21 CFR 886.4230 - Ophthalmic knife test drum.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ophthalmic knife test drum. 886.4230 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4230 Ophthalmic knife test drum. (a) Identification. An ophthalmic knife test drum is a device intended to test the keenness of ophthalmic...

  12. 21 CFR 886.4230 - Ophthalmic knife test drum.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic knife test drum. 886.4230 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4230 Ophthalmic knife test drum. (a) Identification. An ophthalmic knife test drum is a device intended to test the keenness of ophthalmic...

  13. 21 CFR 886.4230 - Ophthalmic knife test drum.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ophthalmic knife test drum. 886.4230 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4230 Ophthalmic knife test drum. (a) Identification. An ophthalmic knife test drum is a device intended to test the keenness of ophthalmic...

  14. Gamma Knife Surgery in Trigeminal Neuralgia.

    PubMed

    Wolf, Amparo; Kondziolka, Douglas

    2016-07-01

    Gamma knife surgery (GKS) represents a safe, effective, and relatively durable noninvasive treatment option for patients with trigeminal neuralgia (TN) and recurrent TN. By one year's time, 75% to 90% of patients will have obtained pain relief, defined as Barrow Neurological Institute grades I to IIIB. Similar rates have been demonstrated for patients undergoing a second GKS for recurrent TN. Predictors of durability of GKS in TN include type I TN, post-GKS Barrow Neurological Institute score, and the presence of post-Gamma Knife facial numbness. PMID:27324996

  15. Climatic control of bedrock river incision.

    PubMed

    Ferrier, Ken L; Huppert, Kimberly L; Perron, J Taylor

    2013-04-11

    Bedrock river incision drives the development of much of Earth's surface topography, and thereby shapes the structure of mountain belts and modulates Earth's habitability through its effects on soil erosion, nutrient fluxes and global climate. Although it has long been expected that river incision rates should depend strongly on precipitation rates, quantifying the effects of precipitation rates on bedrock river incision rates has proved difficult, partly because river incision rates are difficult to measure and partly because non-climatic factors can obscure climatic effects at sites where river incision rates have been measured. Here we present measurements of river incision rates across one of Earth's steepest rainfall gradients, which show that precipitation rates do indeed influence long-term bedrock river incision rates. We apply a widely used empirical law for bedrock river incision to a series of rivers on the Hawaiian island of Kaua'i, where mean annual precipitation ranges from 0.5 metres to 9.5 metres (ref. 12)-over 70 per cent of the global range-and river incision rates averaged over millions of years can be inferred from the depth of river canyons and the age of the volcanic bedrock. Both a time-averaged analysis and numerical modelling of transient river incision reveal that the long-term efficiency of bedrock river incision across Kaua'i is positively correlated with upstream-averaged mean annual precipitation rates. We provide theoretical context for this result by demonstrating that our measurements are consistent with a linear dependence of river incision rates on stream power, the rate of energy expenditure by the flow on the riverbed. These observations provide rare empirical evidence for the long-proposed coupling between climate and river incision, suggesting that previously proposed feedbacks among topography, climate and tectonics may occur. PMID:23579679

  16. Durability of Cutting Performance of a Knife and Micro-Structural Change of a Knife Edge

    NASA Astrophysics Data System (ADS)

    Takekoshi, Kunio; Gotoh, Manabu

    The tested knife material here is mainly SUS420J2 (a kind of stainless steel). This kind of knife is very popular for daily use. From SEM observation of the initial state of the knife-edge tip after the burr removal treatment, we find either some burr and/or a micro-groove, or no burr and no micro-groove along the edge-tip. In order to abrade intentionally, the edge of a knife is repeatedly rubbed perpendicularly to the surface of a Japanese cypress woodblock using the durability-testing machine. During this rubbing process, the abrasion and/or crushing of the edge tip are observed by SEM in detail. The frictional load between the knife-edge and the woodblock is measured. Using the cutting-test machine, the cutting performance of the abraded knives is evaluated by the number of cut pieces of paper. It is discovered that the groove evolves and grows on the edge tip with abrading operation. Moreover, it is concluded that both micro-sidewalls of the groove play a role as cutting edges (i. e., the secondary edge) and this secondary edge and the groove width govern the durability of cutting performance of the knife. Especially the groove width governs it most. These conclusions are also valid for the knives made of other materials such as SUS410 and SUP10.

  17. The “Knife-Cut Sign” Revisited

    PubMed Central

    Cohen, Philip R.

    2015-01-01

    Background: The “knife-cut sign” is a distinctive presentation of linear erosive herpes simplex virus infection in immunocompromised patients. Purpose: To describe a man whose herpes simplex virus infection-related skin lesions demonstrated the “knife-cut sign” and to review the characteristics of reported immunosuppressed individuals with “knife-cut” cutaneous herpes simplex virus lesions. Methods: A man with multiple myeloma and post-stem cell transplant cutaneous graft-versus-host disease managed with systemic prednisone and sirolimus developed disseminated cutaneous herpes simplex virus infection with virus-associated linear ulcers of the inguinal folds and the area between his ear and scalp; the lesions at both sites had a distinctive “knife-cut” appearance. Using the PubMed database, an extensive literature search was performed on herpes simplex virus, immunocompromised patient, and “knife-cut sign”. Results: Herpes simplex virus infection-associated skin lesions that demonstrate the “knife-cut sign” present in patients who are immunosuppressed secondary to either an underlying medical condition or a systemic therapy or both. The distinctive virus-related cutaneous lesions appear as linear ulcers and fissures in intertriginous areas, such as the folds in the inguinal area, the vulva, and the abdomen; in addition, other sites include beneath the breast, within the gluteal cleft, and the area between the ear and the scalp. Not only herpes simplex virus-2, but also herpes simplex virus-1 has been observed as the causative viral serotype; indeed, herpes simplex virus-1 has been associated with genital and inframammary lesions in addition to those above the neck. Direct fluorescent antibody testing is a rapid method for confirming the clinically suspected viral infection; however, since false-negative direct fluorescent antibody testing occurred in some of the patients, it may be prudent to also perform viral cultures and possibly lesional

  18. Experimental Bedrock Channel Incision: Scaling, Sculpture and Sediment Transport

    NASA Astrophysics Data System (ADS)

    Johnson, J. P.; Whipple, K. X.

    2004-12-01

    flux (all else held equal) causes renewed incision, but of an even narrower inner channel; increasing the sediment flux leads to inner channel deposition. Where erosion is most vigorous, sediment generally moving as saltating bedload becomes locally suspended by upward-directed mean flow. For example, swirling clouds of "bedload" particles are continuously suspended by vortices developed within potholes such that the upward flux of particles out of the potholes balance the total sediment flux through the flume. Potholes spontaneously form where average bed slope and fluid velocities were highest, dramatically accelerating the local erosion rate. Our experimental potholes are smaller in scale but morphologically strikingly similar to many observed in the field, and include features such as corkscrew grooves down the outside walls and a protruding horn at the pothole center. More generally, abrasion becomes focused in places where the flow is spatially accelerated, such as in scoops and bends with high curvature. The knife-edge margins and spatial distribution of erosional forms indicate abrupt transitions in erosional efficiency that are tightly coupled to near-bed fluid flow patterns, which in turn are strongly influenced by the erosional forms themselves. Our experiments suggest that, in highly sculpted bedrock channels, naturally developed bed roughness presents a physical length scale that is important to controlling the interaction between sediment impacts and the bed, rather than a length scale based explicitly on sediment transport and average flow conditions such as the saltation hop length.

  19. Hillslope-derived blocks retard river incision

    NASA Astrophysics Data System (ADS)

    Shobe, Charles M.; Tucker, Gregory E.; Anderson, Robert S.

    2016-05-01

    The most common detachment-limited river incision models ignore the effects of sediment on fluvial erosion, yet steep reaches of mountain rivers often host clusters of large (>1 m) blocks. We argue that this distribution of blocks is a manifestation of an autogenic negative feedback in which fast vertical river incision steepens adjacent hillslopes, which deliver blocks to the channel. Blocks inhibit incision by shielding the bed and enhancing form drag. We explore this feedback with a 1-D channel-reach model in which block delivery by hillslopes depends on the river incision rate. Results indicate that incision-dependent block delivery can explain the block distribution in Boulder Creek, Colorado. The proposed negative feedback may significantly slow knickpoint retreat, channel adjustment, and landscape response compared to rates predicted by current theory. The influence of hillslope-derived blocks may complicate efforts to extract base level histories from river profiles.

  20. A method for studying knife tool marks on bone.

    PubMed

    Shaw, Kai-Ping; Chung, Ju-Hui; Chung, Fang-Chun; Tseng, Bo-Yuan; Pan, Chih-Hsin; Yang, Kai-Ting; Yang, Chun-Pang

    2011-07-01

    The characteristics of knife tool marks retained on hard tissues can be used to outline the shape and angle of a knife. The purpose of this study was to describe such marks on bone tissues that had been chopped with knives. A chopping stage with a gravity accelerator and a fixed bone platform was designed to reconstruct the chopping action. A digital microscope was also used to measure the knife angle (θ) and retained V-shape tool mark angle (ψ) in a pig skull. The κ value (elasticity coefficient; θ/ψ) was derived and recorded after the knife angle (θ) and the accompanied velocity were compared with the proportional impulsive force of the knife and ψ on the bone. The constant impulsive force revealed a correlation between the V-shape tool mark angle (ψ) and the elasticity coefficient (κ). These results describe the tool marks--crucial in the medicolegal investigation--of a knife on hard tissues. PMID:21480893

  1. Relaxed Intensity

    ERIC Educational Resources Information Center

    Ramey, Kyle

    2004-01-01

    Relaxed intensity refers to a professional philosophy, demeanor, and way of life. It is the key to being an effective educational leader. To be successful one must be relaxed, which means managing stress efficiently, having fun, and enjoying work. Intensity allows one to get the job done and accomplish certain tasks or goals. Educational leaders…

  2. Gamma Knife Radiosurgery for Choroidal Hemangioma

    SciTech Connect

    Kim, Yun Taek; Kang, Se Woong; Lee, Jung-Il

    2011-12-01

    Purpose: Patients with choroidal hemangioma (CH), a benign ocular hamartoma, frequently presents with visual disturbance as a result of exudative retinal detachment (RD), which originates in subretinal fluid accumulation. We report our experience using the Leksell Gamma Knife in the management of symptomatic CH. Methods and Materials: Seven patients with symptomatic CH (circumscribed form in 3 patients and diffuse form in 4) were treated with the Leksell Gamma Knife at our institution during a 7-year period. All patients presented with exudative RD involving the macula that resulted in severe visual deterioration. The prescription dose to the target margin was 10 Gy in all cases. The mean tumor volume receiving the prescription dose was 536 mm{sup 3} (range, 151-1,057). The clinical data were analyzed in a retrospective fashion after a mean follow-up of 34.4 months (range, 9-76). Results: The resolution of exudative RD was achieved within 6 months, and the visual acuity of the affected eye had improved at the latest follow-up examination (p = .018) in all patients. No recurrence of exudative RD occurred. Thinning of the CHs was observed in most patients; however, symptomatic radiation toxicity had not developed in any of the patients. Conclusion: Symptomatic CHs can be safely and effectively managed with Gamma Knife radiosurgery using a marginal dose of 10 Gy.

  3. Optimal incision sites to reduce corneal aberration variations after small incision phacoemulsification cataract surgery

    PubMed Central

    Chu, Ling; Zhao, Jiang-Yue; Zhang, Jin-Song; Meng, Jie; Wang, Ming-Wu; Yang, Ya-Jing; Yu, Jia-Ming

    2016-01-01

    AIM To analyze the effect of steep meridian small incision phacoemulsification cataract surgery on anterior, posterior and total corneal wavefront aberration. METHODS Steep meridian small incision phacoemulsification cataract surgery was performed in age-related cataract patients which were divided into three groups according to the incision site: 12 o'clock, 9 o'clock and between 9 and 12 o'clock (BENT) incision groups. The preoperative and 3-month postoperative root mean square (RMS) values of anterior, posterior and total corneal wavefront aberration including coma, spherical aberration, and total higher-order aberrations (HOAs), were measured by Pentacam scheimpflug imaging. The mean preoperative and postoperative corneal wavefront aberrations were documented. RESULTS Total corneal aberration and total lower-order aberrations decreased significantly in three groups after operation. RMS value of total HOAs decreased significantly postoperatively in the 12 o'clock incision group (P<0.001). Corneal spherical aberration was statistically significantly lower after steep meridian small incision phacoemulsification cataract surgery in BENT incision group (P<0.05) and Pearson correlation analysis indicated that spherical aberration changes had no significant relationship with total astigmatism changes in all three corneal incision location. CONCLUSION Corneal incision of phacoemulsification cataract surgery can affect corneal wavefront aberration. The 12 o'clock corneal incision eliminated more HOAs and the spherical aberrations decreased in BENT incision group obviously when we selected steep meridian small incision. Cataract lens replacement using wavefront-corrected intraocular lens combined with optimized corneal incision site would improve ocular aberration results. PMID:27162725

  4. Caring for Your Incision After Surgery

    MedlinePlus

    ... if the incision pulls apart. Should I avoid sun exposure? A healing scar will darken and become more noticeable if it gets sunburned. Limit your sun exposure for the first 6 months after surgery. When ...

  5. Clear Corneal Incision in Cataract Surgery

    PubMed Central

    Al Mahmood, Ammar M.; Al-Swailem, Samar A.; Behrens, Ashley

    2014-01-01

    Since the introduction of sutureless clear corneal cataract incisions, the procedure has gained increasing popularity worldwide because it offers several advantages over the traditional sutured scleral tunnels and limbal incisions. Some of these benefits include lack of conjunctival trauma, less discomfort and bleeding, absence of suture-induced astigmatism, and faster visual rehabilitation. However, an increasing incidence of postoperative endophthalmitis after clear corneal cataract surgery has been reported. Different authors have shown a significant increase up to 15-fold in the incidence of endophthalmitis following clear corneal incision compared to scleral tunnels. The aim of this report is to review the advantages and disadvantages of clear corneal incisions in cataract surgery, emphasizing on wound construction recommendations based on published literature. PMID:24669142

  6. Clear corneal incision in cataract surgery.

    PubMed

    Al Mahmood, Ammar M; Al-Swailem, Samar A; Behrens, Ashley

    2014-01-01

    Since the introduction of sutureless clear corneal cataract incisions, the procedure has gained increasing popularity worldwide because it offers several advantages over the traditional sutured scleral tunnels and limbal incisions. Some of these benefits include lack of conjunctival trauma, less discomfort and bleeding, absence of suture-induced astigmatism, and faster visual rehabilitation. However, an increasing incidence of postoperative endophthalmitis after clear corneal cataract surgery has been reported. Different authors have shown a significant increase up to 15-fold in the incidence of endophthalmitis following clear corneal incision compared to scleral tunnels. The aim of this report is to review the advantages and disadvantages of clear corneal incisions in cataract surgery, emphasizing on wound construction recommendations based on published literature. PMID:24669142

  7. The oblique mastectomy incision: advantages and outcomes.

    PubMed

    Gronet, Edward M; Halvorson, Eric G

    2014-01-01

    Mastectomy has traditionally been performed using a transverse elliptical incision. The disadvantages of this approach are a potentially visible scar medially and poor subincisional soft-tissue coverage of implants laterally. A more natural and aesthetic result is obtained with an oblique incision running parallel to the pectoralis major muscle fibers. This approach offers women more freedom of choice in clothing as well as the potential for complete subincisional muscle coverage in alloplastic breast reconstruction, in addition to other functional advantages. PMID:24835870

  8. Knife River Indian Villages National Historic Site: Teacher's Guide.

    ERIC Educational Resources Information Center

    National Park Service (Dept. of Interior), Washington, DC. National Register of Historic Places.

    This guide provides history and social studies teachers, at all grade levels, with information and activities about the American Indians of the Northern Plains who lived in the area of the Knife River where it enters the Missouri River. Located in what is now North Dakota, this area is the Knife River Indian Villages National Historic Site. The…

  9. DNA Methylation Modulates Nociceptive Sensitization after Incision

    PubMed Central

    Sun, Yuan; Sahbaie, Peyman; Liang, DeYong; Li, Wenwu; Shi, Xiaoyou; Kingery, Paige; Clark, J. David

    2015-01-01

    DNA methylation is a key epigenetic mechanism controlling DNA accessibility and gene expression. Blockade of DNA methylation can significantly affect pain behaviors implicated in neuropathic and inflammatory pain. However, the role of DNA methylation with regard to postoperative pain has not yet been explored. In this study we sought to investigate the role of DNA methylation in modulating incisional pain and identify possible targets under DNA methylation and contributing to incisional pain. DNA methyltranferase (DNMT) inhibitor 5-Aza-2′-deoxycytidine significantly reduced incision-induced mechanical allodynia and thermal sensitivity. Aza-2′-deoxycytidine also reduced hindpaw swelling after incision, suggesting an anti-inflammatory effect. Global DNA methylation and DNMT3b expression were increased in skin after incision, but none of DNMT1, DNMT3a or DNMT3b was altered in spinal cord or DRG. The expression of proopiomelanocortin Pomc encoding β-endorphin and Oprm1 encoding the mu-opioid receptor were upregulated peripherally after incision; moreover, Oprm1 expression was further increased under DNMT inhibitor treatment. Finally, local peripheral injection of the opioid receptor antagonist naloxone significantly exacerbated incision-induced mechanical hypersensitivity. These results suggest that DNA methylation is functionally relevant to incisional nociceptive sensitization, and that mu-opioid receptor signaling might be one methylation regulated pathway controlling sensitization after incision. PMID:26535894

  10. DNA Methylation Modulates Nociceptive Sensitization after Incision.

    PubMed

    Sun, Yuan; Sahbaie, Peyman; Liang, DeYong; Li, Wenwu; Shi, Xiaoyou; Kingery, Paige; Clark, J David

    2015-01-01

    DNA methylation is a key epigenetic mechanism controlling DNA accessibility and gene expression. Blockade of DNA methylation can significantly affect pain behaviors implicated in neuropathic and inflammatory pain. However, the role of DNA methylation with regard to postoperative pain has not yet been explored. In this study we sought to investigate the role of DNA methylation in modulating incisional pain and identify possible targets under DNA methylation and contributing to incisional pain. DNA methyltranferase (DNMT) inhibitor 5-Aza-2'-deoxycytidine significantly reduced incision-induced mechanical allodynia and thermal sensitivity. Aza-2'-deoxycytidine also reduced hindpaw swelling after incision, suggesting an anti-inflammatory effect. Global DNA methylation and DNMT3b expression were increased in skin after incision, but none of DNMT1, DNMT3a or DNMT3b was altered in spinal cord or DRG. The expression of proopiomelanocortin Pomc encoding β-endorphin and Oprm1 encoding the mu-opioid receptor were upregulated peripherally after incision; moreover, Oprm1 expression was further increased under DNMT inhibitor treatment. Finally, local peripheral injection of the opioid receptor antagonist naloxone significantly exacerbated incision-induced mechanical hypersensitivity. These results suggest that DNA methylation is functionally relevant to incisional nociceptive sensitization, and that mu-opioid receptor signaling might be one methylation regulated pathway controlling sensitization after incision. PMID:26535894

  11. [LASER CONISATION VS. COLD KNIFE CONISATION FOR CIN].

    PubMed

    Karagyozov, I

    2016-01-01

    For the period of 5 years (2008-2012) at the outpatient department and the operation theater of Tokuda hospital 280 conisations were done--135 lasers and 145 cold knifes. Indications for the operation were common, with no specific choice for the aim of comparison. All patients had proven colposcopic or histologic dysplasia of the cervix. The operations were performed 2 or 3 days after menstruation. Laser conisations received local anesthesia and were not hospitalized. Cold knife conisations were done at the operation theater under regional anesthesia, they attended the hospital for 24 hours, had vaginal tapenade and urethral catheter. Indications for the operation were as follows: CIN I-14 laser and 38 cold knife conisations; CIN II-30 laser and 28 cold knife conisations; CIN III--CIS-73 laser and 74 cold knife conisations. The follow up is: 2 months after the operation-colposcopy and every 3 months afterwards--PAP smear and colposcopy for 1 year. PMID:27514128

  12. Natural orifice transluminal endoscopic wedge hepatic resection with a water-jet hybrid knife in a non-survival porcine model

    PubMed Central

    Shi, Hong; Jiang, Sheng-Jun; Li, Bin; Fu, Deng-Ke; Xin, Pei; Wang, Yong-Guang

    2011-01-01

    AIM: To explore the feasibility of a water-jet hybrid knife to facilitate wedge hepatic resection using a natural orifice transluminal endoscopic surgery (NOTES) approach in a non-survival porcine model. METHODS: The Erbe Jet2 water-jet system allows a needleless, tissue-selective hydro-dissection with a pre-selected pressure. Using this system, wedge hepatic resection was performed through three natural routes (trans-anal, trans-vaginal and trans-umbilical) in three female pigs weighing 35 kg under general anesthesia. Entry into the peritoneal cavity was via a 15-mm incision using a hook knife. The targeted liver segment was marked by an APC probe, followed by wedge hepatic resection performed using a water-jet hybrid knife with the aid of a 4-mm transparent distance soft cap mounted onto the tip of the endoscope for holding up the desired plane. The exposed vascular and ductal structures were clipped with Endoclips. Hemostasis was applied to the bleeding cut edges of the liver parenchyma by electrocautery. After the procedure, the incision site was left open, and the animal was euthanized followed by necropsy. RESULTS: Using the Erbe Jet2 water-jet system, trans-anal and trans-vaginal wedge hepatic resection was successfully performed in two pigs without laparoscopic assistance. Trans-umbilical attempt failed due to an unstable operating platform. The incision for peritoneal entry took 1 min, and about 2 h was spent on excision of the liver tissue. The intra-operative blood loss ranged from 100 to 250 mL. Microscopically, the hydro-dissections were relatively precise and gentle, preserving most vessels. CONCLUSION: The Erbe Jet2 water-jet system can safely accomplish non-anatomic wedge hepatic resection in NOTES, which deserves further studies to shorten the dissection time. PMID:21412502

  13. Low-power holmium:YAG laser urethrotomy for urethral stricture disease: comparison of outcomes with the cold-knife technique.

    PubMed

    Atak, Mustafa; Tokgöz, Hüsnü; Akduman, Bülent; Erol, Bülent; Dönmez, Ibrahim; Hancı, Volkan; Türksoy, Ozlem; Mungan, Necmettin Aydın

    2011-11-01

    In this prospective randomized clinical trial, we aimed to evaluate the safety and efficacy of endourethrotomy with holmium:yttrium-aluminium-garnet (HO:YAG) laser and compare the outcomes with the conventional cold-knife urethrotomy. Fifty-one male patients with single, iatrogenic, annular strictures of the urethra were randomly divided into two groups; 21 patients who underwent direct-vision endoscopic urethrotomy with Ho:YAG laser (15 W; 1,200-1,400 mJ; 8-12 Hz) at 12 o'clock position (laser group) and 30 patients who underwent direct-vision endoscopic urethrotomy with cold-knife incision at 12 o'clock position (cold-knife group). The results obtained were analyzed and compared at 3 months, 6 months, 9 months, and 12 months postoperatively by clinical evaluation, uroflowmetry, and retrograde urethrographies. Variables were compared among groups using Fisher's exact and Mann Whitney U tests. There were no differences between two groups in terms of patient age, preoperative Qmax value, stricture location, and length. Operative time was shorter in laser group (16.4 ± 8.04 minutes) when compared with cold-knife group (23.8 ± 5.47 minutes) (p<0.001). Recurrence-free rate at 3 months was similar between two groups (p=0.122). However, recurrence-free rates at 6 months, 9 months, and 12 months were significantly higher in laser group when compared with cold-knife group (p values were 0.045, 0.027, and 0.04, respectively). No intra- or postoperative complications were encountered. Use of Ho:YAG laser in the management of urethral stricture disease is a safe and effective method. In addition, it provides shorter operative time and lower recurrence rate when compared with the conventional technique. PMID:22005159

  14. Relaxation System

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Environ Corporation's relaxation system is built around a body lounge, a kind of super easy chair that incorporates sensory devices. Computer controlled enclosure provides filtered ionized air to create a feeling of invigoration, enhanced by mood changing aromas. Occupant is also surrounded by multidimensional audio and the lighting is programmed to change colors, patterns, and intensity periodically. These and other sensory stimulators are designed to provide an environment in which the learning process is stimulated, because research has proven that while an individual is in a deep state of relaxation, the mind is more receptive to new information.

  15. Comparison of surgically induced astigmatism in various incisions in manual small incision cataract surgery

    PubMed Central

    Jauhari, Nidhi; Chopra, Deepak; Chaurasia, Rajan Kumar; Agarwal, Ashutosh

    2014-01-01

    AIM To determine the surgically induced astigmatism (SIA) in Straight, Frown and Inverted V shape (Chevron) incisions in manual small incision cataract surgery (SICS). METHODS A prospective cross sectional study was done on a total of 75 patients aged 40y and above with senile cataract. The patients were randomly divided into three groups (25 each). Each group received a particular type of incision (Straight, Frown or Inverted V shape incisions). Manual SICS with intraocular lens (IOL) implantation was performed. The patients were compared 4wk post operatively for uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA) and SIA. All calculations were performed using the SIA calculator version 2.1, a free software program. The study was analyzed using SPSS version 15.0 statistical analysis software. RESULTS The study found that 89.5% of patients in Straight incision group, 94.2% in Frown incision group and 95.7% in Inverted V group attained BCVA post-operatively in the range of 6/6 to 6/18. Mean SIA was minimum (-0.88±0.61D×90 degrees) with Inverted V incision which was statistically significant. CONCLUSION Inverted V (Chevron) incision gives minimal SIA. PMID:25540754

  16. Transconjunctival incision for total maxillectomy--an alternative for subciliary incision.

    PubMed

    Goyal, Amit; Tyagi, Isha; Jain, Shilpa; Syal, Rajan; Singh, Alok Pratap; Kapila, Rajeev

    2011-09-01

    A subciliary incision may be associated with various complications of the lower eyelid when it is used during a total maxillectomy. The use of the transconjunctival incision instead is an alternative in suitable patients. The records of 17 patients were reviewed in whom a transconjunctival incision was used during total maxillectomy. These included 13 in whom the Weber-Ferguson incision was used, and 4 who had a sublabial incision. There was mild conjunctival oedema in all the cases during the immediate postoperative period but it did not last for more than two days. Four patients had mild to moderate oedema of the lid that resolved within two days. One had mild ectropion with transient epiphora, which was caused by early removal of the medial canthal sutures. We found the approach to be cosmetically acceptable as it avoids a scar in the subciliary region. The transconjunctival incision can be used in place of the subciliary incision for lateral exposure during total maxillectomy. There are few complications associated with the lower lid, and it has good cosmetic results; if it is combined with a sublabial incision in suitable patients, the maxillectomy is virtually scar-free. PMID:20673694

  17. Knife and impact cutting of lamb bone.

    PubMed

    King, M J

    1999-05-01

    The forces and hence fracture energies required to cut bone are presented in this paper and the merits of cutting with a high speed blade are considered. A plain knife blade was used to cut cancellous and compact lamb bone using three different methods. A microtome was used to produce a range of cut thicknesses which enabled the fracture energy to be separated into friction, surface fracture and plastic deformation energies. A tensile test machine was used to produce thicker off-cuts so that the energy required to cut through full sections of bone could be determined. A high speed rail gun was used to cut at speeds up to 130 m/s. The energy required to cut bone did not change with blade speed. However, the energies measured during the cutting varied over a wide range. In situations in which the surface of the cut bone exhibited a very uneven surface high energy was required, whereas when the resulting cut surface was planar the cutting energy was low. A light weight blade which impacts the bone at high speed will transmit a small impulse to the carcass which may be absorbed without transmitting strain to the muscle/connective tissue. This may allow the development of a high speed knife which will cut bone without excessively damaging the meat surrounding the cut. PMID:22062140

  18. Peripheral dose in ocular treatments with CyberKnife and Gamma Knife radiosurgery compared to proton radiotherapy.

    PubMed

    Zytkovicz, A; Daftari, I; Phillips, T L; Chuang, C F; Verhey, L; Petti, P L

    2007-10-01

    Peripheral radiation can have deleterious effects on normal tissues throughout the body, including secondary cancer induction and cataractogenesis. The aim of this study is to evaluate the peripheral dose received by various regions of the body after ocular treatment delivered with the Model C Gamma Knife, proton radiotherapy with a dedicated ocular beam employing no passive-scattering system, or a CyberKnife unit before and after supplemental shielding was introduced. TLDs were used for stray gamma and x-ray dosimetry, whereas CR-39 dosimeters were used to measure neutron contamination in the proton experiments. Doses to the contralateral eye, neck, thorax and abdomen were measured on our anthropomorphic phantom for a 56 Gy treatment to a 588 mm(3) posterior ocular lesion. Gamma Knife (without collimator blocking) delivered the highest dose in the contralateral eye, with 402-2380 mSv, as compared with 118-234 mSv for CyberKnife pre-shielding, 46-255 mSv for CyberKnife post-shielding and 9-12 mSv for proton radiotherapy. Gamma Knife and post-shielding CyberKnife delivered comparable doses proximal to the treatment site, with 190 versus 196 mSv at the thyroid, whereas protons doses at these locations were less than 10 mSv. Gamma Knife doses decreased dramatically with distance from the treatment site, delivering only 13 mSv at the lower pelvis, comparable to the proton result of 4 to 7 mSv in this region. In contrast, CyberKnife delivered between 117 and 132 mSv to the lower pelvis. In conclusion, for ocular melanoma treatments, a proton beam employing no double scattering system delivers the lowest peripheral doses proximally to the contralateral eye and thyroid when compared to radiosurgery with the Model C Gamma Knife or CyberKnife. At distal locations in the pelvis, peripheral doses delivered with proton and Gamma Knife are of an order of magnitude smaller than those delivered with CyberKnife. PMID:17881812

  19. Peripheral dose in ocular treatments with CyberKnife and Gamma Knife radiosurgery compared to proton radiotherapy

    NASA Astrophysics Data System (ADS)

    Zytkovicz, A.; Daftari, I.; Phillips, T. L.; Chuang, C. F.; Verhey, L.; Petti, P. L.

    2007-09-01

    Peripheral radiation can have deleterious effects on normal tissues throughout the body, including secondary cancer induction and cataractogenesis. The aim of this study is to evaluate the peripheral dose received by various regions of the body after ocular treatment delivered with the Model C Gamma Knife, proton radiotherapy with a dedicated ocular beam employing no passive-scattering system, or a CyberKnife unit before and after supplemental shielding was introduced. TLDs were used for stray gamma and x-ray dosimetry, whereas CR-39 dosimeters were used to measure neutron contamination in the proton experiments. Doses to the contralateral eye, neck, thorax and abdomen were measured on our anthropomorphic phantom for a 56 Gy treatment to a 588 mm3 posterior ocular lesion. Gamma Knife (without collimator blocking) delivered the highest dose in the contralateral eye, with 402-2380 mSv, as compared with 118-234 mSv for CyberKnife pre-shielding, 46-255 mSv for CyberKnife post-shielding and 9-12 mSv for proton radiotherapy. Gamma Knife and post-shielding CyberKnife delivered comparable doses proximal to the treatment site, with 190 versus 196 mSv at the thyroid, whereas protons doses at these locations were less than 10 mSv. Gamma Knife doses decreased dramatically with distance from the treatment site, delivering only 13 mSv at the lower pelvis, comparable to the proton result of 4 to 7 mSv in this region. In contrast, CyberKnife delivered between 117 and 132 mSv to the lower pelvis. In conclusion, for ocular melanoma treatments, a proton beam employing no double scattering system delivers the lowest peripheral doses proximally to the contralateral eye and thyroid when compared to radiosurgery with the Model C Gamma Knife or CyberKnife. At distal locations in the pelvis, peripheral doses delivered with proton and Gamma Knife are of an order of magnitude smaller than those delivered with CyberKnife.

  20. OCT-Documented Incision Features and Natural History of Clear Corneal Incisions Used for Bimanual Microincision Cataract Surgery

    PubMed Central

    Lyles, Graham W.; Cohen, Kenneth L.; Lam, Diana

    2013-01-01

    Purpose Use of anterior segment OCT to identify features and natural history of bimanual incisions used only for phacoemulsification and a main incision used only for intraocular lens insertion. Methods Prospective study of 25 subjects who had uncomplicated bimanual phacoemulsification. The Zeiss Visante OCT identified incisions at 1 day, 1 week, and 1 month postoperatively. The absence or presence of features, endothelial gaping, detachment of the Descemet membrane, endothelial misalignment, epithelial gaping, and/or loss of coaptation, was recorded. Main incision data were compared with bimanual incision data. The difference for each feature, between the main incision and the bimanual incision, at each time point and over time were calculated. Results The most common findings at 1 day, 1 week, and 1 month were main incision endothelial misalignment (52%) and bimanual incision endothelial gape (24%), main incision endothelial misalignment (60%) and bimanual incision endothelial gape (22%), and main incision endothelial misalignment (35%) and bimanual incision endothelial misalignment (14%), respectively. Only at 1 day and 1 week was endothelial misalignment significantly more common in the main incision (P = 0.0352 and 0.0005, respectively). The only other incision feature that differed significantly was endothelial gape, which was more frequent in the bimanual incision at 1 week (P = 0.0391). For each incision feature combined over all time periods, only endothelial misalignment was significantly more prevalent in the main incision (P = 0.0004), whereas endothelial gape was more common in the bimanual incision (P = 0.0352). Conclusions Using OCT, bimanual phacoemulsification did not adversely affect the anatomic incision integrity and healing. PMID:21242779

  1. Feasibility and acute healing of vocal fold microflap incisions in a rabbit model

    PubMed Central

    Suehiro, Atsushi; Bock, Jonathan M.; Hall, Joseph E.; Garrett, C. Gaelyn; Rousseau, Bernard

    2012-01-01

    Objectives The purpose of this study was to: 1) investigate the feasibility of performing mucosal elevation of a vocal fold microflap in a rabbit model, and 2) measure the acute healing of rabbit microflap incisions compared to control vocal folds. Study Design Prospective animal study Methods Ten New Zealand white rabbits were used in this study. All rabbits received a 3mm incision through the epithelium of one vocal fold using a sickle knife and mucosal elevation through this incision using a microlaryngeal fine angled spatula. The contralateral vocal fold was left intact to serve as an internal control. Student t tests were used to investigate differences in epithelial thickness, immunohistochemical staining of CD 45, and inflammatory and pro-fibrotic gene expression between vocal folds undergoing microflap and control. Results Exposure of the rabbit larynx was achieved, allowing for the identification of a surgical plane and the creation of a microflap and elevation of the vocal fold mucosa. Hematoxylin-eosin staining revealed no significant differences in epithelial thickness, immunohistochemistry for CD 45 showed no significant differences in CD 45 positive cells, and quantitative PCR revealed no significant differences in IL-1β, TGFβ-1, or COX-2 gene expression between vocal folds undergoing microflap and control. Conclusions We demonstrate the feasibility of vocal fold microflap surgery in a rabbit model. With the advantage of greater access to primers and antibodies for molecular biological studies, the application of the microflap technique in a small animal model such as rabbit has broad implications for future experimental investigations in laryngology. Level of Evidence Animal Research. PMID:22253007

  2. Minimally Invasive Cardiovascular Surgery: Incisions and Approaches

    PubMed Central

    Langer, Nathaniel B.; Argenziano, Michael

    2016-01-01

    Throughout the modern era of cardiac surgery, most operations have been performed via median sternotomy with cardiopulmonary bypass. This paradigm is changing, however, as cardiovascular surgery is increasingly adopting minimally invasive techniques. Advances in patient evaluation, instrumentation, and operative technique have allowed surgeons to perform a wide variety of complex operations through smaller incisions and, in some cases, without cardiopulmonary bypass. With patients desiring less invasive operations and the literature supporting decreased blood loss, shorter hospital length of stay, improved postoperative pain, and better cosmesis, minimally invasive cardiac surgery should be widely practiced. Here, we review the incisions and approaches currently used in minimally invasive cardiovascular surgery. PMID:27127555

  3. Surface characterization of micro-optical components by Foucault's knife-edge method: the case of a micromirror array.

    PubMed

    Zamkotsian, F; Dohlen, K

    1999-11-01

    As micro-optical components are introduced into optical systems, accurate surface characterization becomes important. We describe a method for quantitative evaluation of surface deformations based on Foucault's knife-edge test. By measurement of local slopes, the surface shape of each mirror in a micromirror array has been reconstructed with a subnanometer accuracy. In addition to low-order deformation (tilt, curvature, astigmatism), each mirror is seen to be palm-tree shaped. This may be explained by strain relaxation in the fabrication process. Measurement on a conventional concave mirror confirms our method. PMID:18324186

  4. Gamma knife radiosurgery for pituitary adenomas.

    PubMed

    Ježková, Jana; Marek, Josef

    2016-09-01

    Pituitary adenomas are frequently occurring intracranial neoplasms. The aim of the treatment of pituitary adenomas is to normalize hormonal hypersecretion, to preserve the normal pituitary function, to reserve or treat impaired pituitary function and to control tumor growth and its mechanical effects on the surrounding structures. Treatment modalities include surgical, medical and radiation therapy. Radiosurgery is mainly used as a secondary line treatment after surgery for residual or recurrent tumors. The antiproliferative effect is achieved by LKG irradiation in more than 90% of patients. Regarding the functioning pituitary adenomas, the manifestation of the treatment effect is slow and depends mainly on the type of adenoma. Gamma knife irradiation is safe when the maximal doses to pituitary and infundibulum are respected. PMID:26899535

  5. The transareolar incision for breast augmentation revisited.

    PubMed

    Kompatscher, Peter; Schuler, Christine; Beer, Gertrude M

    2004-01-01

    Of the various possible incisions for breast augmentation, the transareolar access has gained only limited popularity. The potential side effects of this incision are said to be altered nipple sensation, impaired lactation, an increased rate of infections with capsular fibrosis, well visible scar formation with hypopigmentation, and the need for an additional access in case a breast ptosis correction should prove necessary at a later date. The purpose of this retrospective study was to judge advantages and limitations of transareolar breast augmentation, and to verify whether the reluctant attitude toward this surgical approach is justified. A sample of 18 patients with a transareolar, retropectoral breast augmentation was selected for a retrospective evaluation. The suitability of the technique in general was examined together with early postoperative complications, sensory changes, and late complications on the basis of an evaluation system for cosmetic surgical results. The study showed that only women with an areolar diameter of 3.5 cm or more without pronounced breast ptosis were suitable for the transareolar access. No early infections were noted. The rate of capsular fibrosis was 11%. Two years after breast augmentation, 16 women (89%) judged their breast sensation to be normal, but objective assessment showed that mean pressure and vibration sensation were moderately compromised in all parts of the breast. The scars were of good quality, with very little hypopigmentation. With appropriate patient selection, respecting the advantages and limitations, the transareolar incision has its definite place among the different incisions for breast augmentation. PMID:15164231

  6. Small incision lenticule extraction (SMILE) in 2015.

    PubMed

    Chan, Colin; Lawless, Michael; Sutton, Gerard; Versace, Patrick; Hodge, Chris

    2016-05-01

    Small incision lenticule extraction (SMILE) represents a recent addition to the refractive surgeon's range of procedures. Although there remains a number of similarities to existing techniques in terms of patient selection and treatment parameters, consideration is required to optimise patient outcomes and satisfaction. Here, we review the selection criteria, contraindications, indications and existing published safety and efficacy outcomes. PMID:27156103

  7. Trans-umbilical endoscopic cholecystectomy with a water-jet hybrid-knife: A pilot animal study

    PubMed Central

    Jiang, Sheng-Jun; Shi, Hong; Swar, Gyanendra; Wang, Hai-Xia; Liu, Xiao-Jing; Wang, Yong-Guang

    2013-01-01

    AIM: To investigate the feasibility and safety of Natural orifice trans-umbilical endoscopic cholecystectomy with a water-jet hybrid-knife in a non-survival porcine model. METHODS: Pure natural orifice transluminal endoscopic surgery (NOTES) cholecystectomy was performed on three non-survival pigs, by transumbilical approach, using a water-jet hybrid-knife. Under general anesthesia, the following steps detailed the procedure: (1) incision of the umbilicus followed by the passage of a double-channel flexible endsocope through an overtube into the peritoneal cavity; (2) establishment of pneumoperitoneum; (3) abdominal exploration; (4) endoscopic cholecystectomy: dissection of the gallbladder performed using water jet equipment, ligation of the cystic artery and duct conducted using nylon loops; and (5) necropsy with macroscopic evaluation. RESULTS: Transumbilical endoscopic cholecystectomy was successfully completed in the first and third pig, with minor bleedings. The dissection times were 137 and 42 min, respectively. The total operation times were 167 and 69 min, respectively. And the lengths of resected specimen were 6.5 and 6.1 cm, respectively. Instillation of the fluid into the gallbladder bed produced edematous, distended tissue making separation safe and easy. Reliable ligation using double nylon loops insured the safety of cutting between the loops. There were no intraoperative complications or hemodynamic instability. Uncontrolled introperative bleeding occurred in the second case, leading to the operation failure. CONCLUSION: Pure NOTES trans-umbilical cholecystectomy with a water-jet hybrid-knife appears to be feasible and safe. Further investigation of this technique with long-term follow-up in animals is needed to confirm the preliminary observation. PMID:24187461

  8. Treatment of epidermoid tumors with gamma knife radiosurgery: Case series

    PubMed Central

    Vasquez, Javier A. Jacobo; Fonnegra, Julio R.; Diez, Juan C.; Fonnegra, Andres

    2016-01-01

    Background: Epidermoid tumors (ETs) are benign lesions that are treated mainly by means of surgical resection, with overall good results. External beam radiotherapy is an alternative treatment for those recurrent tumors, in which a second surgery might not be the best choice for the patient. A little information exists about the effectiveness of gamma knife radiosurgery for the treatment of newly diagnosed and recurrent ETs. We present three cases of ETs treated with gamma knife radiosurgery. Case Description: Case 1 is a 21-year-old female with an ET located in the left cerebellopontine angle (CPA) with symptoms related to VIII cranial nerve dysfunction. Symptom control was achieved and maintained after single session radiosurgery with gamma knife. Case 2 is a 59-year-old female patient with the history of trigeminal neuralgia secondary to a recurrent ET located in the left CPA. Significant pain improvement was achieved after treatment with gamma knife radiosurgery. Case 3 is a 29-year-old male patient with a CPA ET causing long lasting trigeminal neuralgia, pain relief was achieved in this patient after gamma knife radiosurgery. Conclusion: Long-term symptom relief was achieved in all three cases proving that gamma knife radiosurgery is a good and safe alternative for patients with recurrent or nonsurgically treated ETs. PMID:26958427

  9. Drainage basins and channel incision on Mars

    PubMed Central

    Aharonson, Oded; Zuber, Maria T.; Rothman, Daniel H.; Schorghofer, Norbert; Whipple, Kelin X.

    2002-01-01

    Measurements acquired by the Mars Orbiter Laser Altimeter on board the Mars Global Surveyor indicate that large drainage systems on Mars have geomorphic characteristics inconsistent with prolonged erosion by surface runoff. We find the topography has not evolved to an expected equilibrium terrain form, even in areas where runoff incision has been previously interpreted. By analogy with terrestrial examples, groundwater sapping may have played an important role in the incision. Longitudinally flat floor segments may provide a direct indication of lithologic layers in the bedrock, altering subsurface hydrology. However, it is unlikely that floor levels are entirely due to inherited structures due to their planar cross-cutting relations. These conclusions are based on previously unavailable observations, including extensive piece-wise linear longitudinal profiles, frequent knickpoints, hanging valleys, and small basin concavity exponents. PMID:16578863

  10. Drainage basins and channel incision on Mars.

    PubMed

    Aharonson, Oded; Zuber, Maria T; Rothman, Daniel H; Schorghofer, Norbert; Whipple, Kelin X

    2002-02-19

    Measurements acquired by the Mars Orbiter Laser Altimeter on board the Mars Global Surveyor indicate that large drainage systems on Mars have geomorphic characteristics inconsistent with prolonged erosion by surface runoff. We find the topography has not evolved to an expected equilibrium terrain form, even in areas where runoff incision has been previously interpreted. By analogy with terrestrial examples, groundwater sapping may have played an important role in the incision. Longitudinally flat floor segments may provide a direct indication of lithologic layers in the bedrock, altering subsurface hydrology. However, it is unlikely that floor levels are entirely due to inherited structures due to their planar cross-cutting relations. These conclusions are based on previously unavailable observations, including extensive piece-wise linear longitudinal profiles, frequent knickpoints, hanging valleys, and small basin concavity exponents. PMID:16578863

  11. Gamma Knife radiosurgery for intracranial hemangioblastoma.

    PubMed

    Silva, Danilo; Grabowski, Mathew M; Juthani, Rupa; Sharma, Mayur; Angelov, Lilyana; Vogelbaum, Michael A; Chao, Samuel; Suh, John; Mohammadi, Alireza; Barnett, Gene H

    2016-09-01

    Gamma knife radiosurgery (GKRS) has become a treatment option for intracranial hemangioblastomas, especially in patients with poor clinical status and also high-risk surgical candidates. The objective of this study was to analyze clinical outcome and tumor control rates. Retrospective chart review revealed 12 patients with a total of 20 intracranial hemangioblastomas treated with GKRS from May 1998 until December 2014. Kaplan-Meier plots were used to calculate the actuarial local tumor control rates and rate of recurrence following GKRS. Univariate analysis, including log rank test and Wilcoxon test were used on the Kaplan-Meier plots to evaluate the predictors of tumor progression. Two-tailed p value of <0.05 was considered as significant. Median follow-up was 64months (2-184). Median tumor volume pre-GKRS was 946mm(3) (79-15970), while median tumor volume post-GKRS was 356mm(3) (30-5404). Complications were seen in two patients. Tumor control rates were 100% at 1year, 90% at 3years, and 85% at 5years, using the Kaplan-Meier method. There were no statistically significant univariate predictors of progression identified, although there was a trend towards successful tumor control in solid tumors (p=0.07). GKRS is an effective and safe option for treating intracranial hemangioblastoma with favorable tumor control rates. PMID:27422585

  12. Gamma knife radiosurgery in 11 hemangioblastomas.

    PubMed

    Niemelä, M; Lim, Y J; Söderman, M; Jääskeläinen, J; Lindquist, C

    1996-10-01

    One suprasellar, one mesencephalic, and nine cerebellar hemangioblastomas were treated with the gamma knife in 10 patients (median age 48 years) in Stockholm between 1978 and 1993. Four patients had von Hippel-Lindau disease, a dominant inherited trait predisposing to multiple hemangioblastomas. Six hemangioblastomas were treated with radiotherapy at a median margin dose of 25 Gy (20-35 Gy) before 1990 and the next five with a median of 10 Gy (5-19 Gy). Computerized tomography or magnetic resonance images were available for 10 of the 11 hemangioblastomas at a median follow-up time of 26 months (4-68 months) after radiosurgery. The solid part of six hemangioblastomas shrank in a median of 30 months, whereas four hemangioblastomas were unchanged at a median of 14 months. Five hemangioblastomas had an adjoining cyst and three of these cysts had to be evacuated after radiosurgery. One solitary hemangioblastoma later developed a de novo cyst that also needed evacuation. One patient with two cerebellar hemangioblastomas (margin dose 25 Gy each) developed edema at 6 months and required a shunt and prolonged corticosteroid treatment. The combined follow-up data of the 23 hemangioblastomas in 15 patients from previous literature and the present series indicate that, first, a solitary small- or medium-sized hemangioblastoma usually shrinks or stops growing after radiosurgery. The recommended margin dose is 10 to 15 Gy. Second, the adjoining cyst often does not respond to radiosurgery but requires later, sometimes repeated evacuation. PMID:8814161

  13. Minimizing the Submandibular Incision in Endoscopic Subcondylar Fracture Repair.

    PubMed

    Aboelatta, Yasser Abdallah; Elbarbary, Amir S; Abdelazeem, Sarah; Massoud, Karim S; Safe, Ikram I

    2015-12-01

    Endoscope-assisted treatment of mandibular condylar fractures is an evolving surgical technique of this controversial subject. The approach is performed through an intraoral and additional submandibular incision. This study presents a technique for minimizing the length of the optional submandibular incision. Ten patients with displaced subcondylar fractures and malocclusion underwent endoscope-assisted open reduction and internal fixation (ORIF). A limited (<1 cm) submandibular incision (dissected under endoscopic guidance from within) was needed in eight patients to complement the intraoral incision and facilitate the reduction in the fractures. Satisfactory small scar could be obtained in all patients with neither wound complications nor facial nerve injuries. Our technique depends on dissection first then incision. Performing the external incision after complete intraoral dissection is safe for the facial nerve and minimizes scarring markedly. This very limited submandibular incision facilitates reduction in relatively difficult cases and enables clear visualization of posterior border of the mandible to confirm adequate fracture reduction. PMID:26576236

  14. The use of a surgical incision management system on vascular surgery incisions: a pilot study.

    PubMed

    Weir, Gregory

    2014-06-01

    Health care-associated infections in hospitals, including surgical site infections, contribute significantly to morbidity as well as mortality. Surgical incision management (SIM) using negative pressure wound therapy (Prevena™ Incision Management System, Kinetic Concepts, Inc., San Antonio, TX, USA) is designed to cover and protect closed surgical incisions from external factors including infectious sources and local trauma, while negative pressure removes fluid and infectious material from the surgical incision. A prospective case-control study assessed wound complications in patients undergoing vascular bypass procedures, where both femoral areas were incised to gain access to the femoral arteries. SIM was placed on one femoral area while a standard postoperative wound dressing was placed on the contralateral femoral area. Eight patients were included in this pilot study. All of them required bilateral femoral artery access. During the follow-up period patients were monitored for wound complications. All wound complications requiring surgical intervention were considered significant. No significant wound complications occurred in wounds treated with SIM, compared with three significant complications in control wounds. These preliminary data would suggest a potential reduction in wound complications and no observed increase in haemorrhage in high-risk patients with severe co-morbidities undergoing vascular surgery. PMID:24851730

  15. Development of an air knife to remove seed coat fragments during lint cleaning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An air knife is a tool commonly used to blow off debris in a manufacturing line. The knife may also be used to break the attachment force between a lint cleaner saw and a seed coat fragment (SCF) with attached fiber, and remove them. Work continued on evaluating an auxiliary air knife mounted on t...

  16. Anomalous primary radiation from the Leksell Gamma Knife Unit.

    PubMed

    Shearer, D R; Roventine, W A; Coy, S R

    1994-12-01

    The Leksell Gamma Knife Unit, Type U, utilizes 201 separate 60Co sources intersecting at a common focus for radiosurgical treatment of the brain. It has been generally understood that all primary unattenuated radiation beams are confined within the protective housing during all phases of Gamma Knife operation. We have found that when the unit's shielding door is lowered for treatment, twelve primary beams exit the unit's door opening. Furthermore, in the original Gamma Knife unit design, two of the twelve primary beams failed to be attenuated by either the unit base or the unit wings. This has implications for the design of structural shielding and the protection of personnel during emergency procedures. Engineering modifications to eliminate the problem are discussed. PMID:7960787

  17. Minimum-incision metatarsal ray resection: an observational case series.

    PubMed

    Roukis, Thomas S

    2010-01-01

    This report describes the results of 17 metatarsal ray resections performed through a minimal incision in 13 consecutive patients. Each patient underwent minimum-incision metatarsal ray resection for either definitive treatment or as the index incision and drainage procedure followed by transmetatarsal amputation. There were 10 male and 3 female patients with a mean age of 68.8 +/- 8.5 years (range, 59-83 years). Twelve patients had diabetes mellitus and 7 had critical limb ischemia. There were 11 right feet and 6 left feet involved, and 3 second, 3 third, 3 fourth, and 8 fifth minimum-incision metatarsal ray resections performed. Direct primary-incision closure was performed 7 times (1 with adjacent percutaneous metatarsal osteotomy), delayed primary closure was performed 4 times (1 with external fixation), and conversion to a transmetatarsal amputation was performed 2 times. Fourteen of 17 minimum-incision metatarsal ray resections were deemed successful. Two failures occurred when skin necrosis developed from excessive tension along the incision line requiring conversion to a transmetatarsal amputation, and the other occurred in a patient with unreconstructed critical limb ischemia who underwent multiple repeated incision and drainage procedures and vascular bypass with ultimate healing via secondary intent. When properly performed in patients with adequate vascular inflow, minimum-incision metatarsal ray resection as the definitive procedure or in conjunction with an incision and drainage for unsalvageable toe infection or gangrene represents a safe, simple, useful technique. PMID:20123288

  18. Breathing and Relaxation

    MedlinePlus

    ... Top Doctors in the Nation Departments & Divisions Home Health Insights Stress & Relaxation Breathing and Relaxation Breathing and Relaxation Make ... Management Assess Your Stress Coping Strategies Identifying ... & Programs Health Insights Doctors & Departments Research & Science Education & Training Make ...

  19. Repeat Gamma Knife Radiosurgery for Trigeminal Neuralgia

    SciTech Connect

    Aubuchon, Adam C.; Chan, Michael D.; Lovato, James F.; Balamucki, Christopher J.; Ellis, Thomas L.; Tatter, Stephen B.; McMullen, Kevin P.; Munley, Michael T.; Deguzman, Allan F.; Ekstrand, Kenneth E.; Bourland, J. Daniel; Shaw, Edward G.

    2011-11-15

    Purpose: Repeat gamma knife stereotactic radiosurgery (GKRS) for recurrent or persistent trigeminal neuralgia induces an additional response but at the expense of an increased incidence of facial numbness. The present series summarized the results of a repeat treatment series at Wake Forest University Baptist Medical Center, including a multivariate analysis of the data to identify the prognostic factors for treatment success and toxicity. Methods and Materials: Between January 1999 and December 2007, 37 patients underwent a second GKRS application because of treatment failure after a first GKRS treatment. The mean initial dose in the series was 87.3 Gy (range, 80-90). The mean retreatment dose was 84.4 Gy (range, 60-90). The dosimetric variables recorded included the dorsal root entry zone dose, pons surface dose, and dose to the distal nerve. Results: Of the 37 patients, 81% achieved a >50% pain relief response to repeat GKRS, and 57% experienced some form of trigeminal dysfunction after repeat GKRS. Two patients (5%) experienced clinically significant toxicity: one with bothersome numbness and one with corneal dryness requiring tarsorraphy. A dorsal root entry zone dose at repeat treatment of >26.6 Gy predicted for treatment success (61% vs. 32%, p = .0716). A cumulative dorsal root entry zone dose of >84.3 Gy (72% vs. 44%, p = .091) and a cumulative pons surface dose of >108.5 Gy (78% vs. 44%, p = .018) predicted for post-GKRS numbness. The presence of any post-GKRS numbness predicted for a >50% decrease in pain intensity (100% vs. 60%, p = .0015). Conclusion: Repeat GKRS is a viable treatment option for recurrent trigeminal neuralgia, although the patient assumes a greater risk of nerve dysfunction to achieve maximal pain relief.

  20. Repeat Gamma Knife surgery for vestibular schwannomas

    PubMed Central

    Lonneville, Sarah; Delbrouck, Carine; Renier, Cécile; Devriendt, Daniel; Massager, Nicolas

    2015-01-01

    Background: Gamma Knife (GK) surgery is a recognized treatment option for the management of small to medium-sized vestibular schwannoma (VS) associated with high-tumor control and low morbidity. When a radiosurgical treatment fails to stop tumor growth, repeat GK surgery can be proposed in selected cases. Methods: A series of 27 GK retreatments was performed in 25 patients with VS; 2 patients underwent three procedures. The median time interval between GK treatments was 45 months. The median margin dose used for the first, second, and third GK treatments was 12 Gy, 12 Gy, and 14 Gy, respectively. Six patients (4 patients for the second irradiation and 2 patients for the third irradiation) with partial tumor regrowth were treated only on the growing part of the tumor using a median margin dose of 13 Gy. The median tumor volume was 0.9, 2.3, and 0.7 cc for the first, second, and third treatments, respectively. Stereotactic positron emission tomography (PET) guidance was used for dose planning in 6 cases. Results: Mean follow-up duration was 46 months (range 24–110). At the last follow-up, 85% of schwannomas were controlled. The tumor volume decreased, remained unchanged, or increased after retreatment in 15, 8, and 4 cases, respectively. Four patients had PET during follow-up, and all showed a significant metabolic decrease of the tumor. Hearing was not preserved after retreatment in any patients. New facial or trigeminal palsy did not occur after retreatment. Conclusions: Our results support the long-term efficacy and low morbidity of repeat GK treatment for selected patients with tumor growth after initial treatment. PMID:26500799

  1. Effect of surface roughness on contact pressure of static seals (Sealing characteristics of knife-edge seals)

    NASA Astrophysics Data System (ADS)

    Matsuzaki, Yoshio; Hosokawa, Kazuo; Funabashi, Koichi

    1992-09-01

    The sealing mechanism of knife-edge seals was investigated experimentally by varying the width of the flat area on the apex of the knife edge. The most suitable shape of the knife edge with the lowest compressive force for sealing was determined, and a new type of knife edge was developed.

  2. Relaxation Assessment with Varied Structured Milieu (RELAX).

    ERIC Educational Resources Information Center

    Cassel, Russell N.; Cassel, Susie L.

    1983-01-01

    Describes Relaxation Assessment with Varied Structured Milieu (RELAX), a clinical program designed to assess the degree to which an individual is able to demonstrate self-control for overall general relaxation. The program is designed for use with the Cassel Biosensors biofeedback equipment. (JAC)

  3. Minimal inframammary incision for breast augmentation

    PubMed Central

    Fanous, Nabil; Tawilé, Caroline; Brousseau, Valérie J

    2008-01-01

    The inframammary approach in breast augmentation, still the most popular technique among plastic surgeons, has always been hampered by the undesirable appearance of its scar. The present paper describes a modified approach to inframammary augmentation with saline-filled prostheses. This approach uses a very short incision, thus resulting in a much less noticeable scar. The surgical technique is easy to learn, simple to execute, does not necessitate any special equipment and gives consistent results. Decreasing the scar length to an absolute minimum ensures higher patient and surgeon satisfaction. PMID:19554159

  4. PROSPECTIVE COMPARATIVE STUDY BETWEEN PROXIMAL TRANSVERSE INCISION AND THE CONVENTIONAL LONGITUDINAL INCISIONS FOR CARPAL TUNNEL RELEASE

    PubMed Central

    Teixeira Alves, Marcelo de Pinho

    2015-01-01

    Carpal tunnel syndrome (CTS) is a pathological condition frequently seen in orthopedic consultation offices. It is most common compressive neuropathy and also the one most often treated surgically. CTS is usually diagnosed clinically, through the clinical history, physical examination (Tinel, Phalen and Durkan tests) and complementary examinations, and more specifically, nerve conduction studies. Ultrasound scans and magnetic resonance imaging may also be used. Conservative treatment is reserved for patients presenting with mild symptoms, with little incapacitation, who show good response to non-steroidal or steroidal anti-inflammatory drugs, physiotherapy and lifestyle changes. Surgical treatment is more frequent, and a variety of techniques are used. The goal of the surgery is to decompress the carpal tunnel and, by sectioning the transverse carpal ligament, release the median nerve. The aim of this paper was to compare surgical treatment of CTS by means of a transverse mini-incision made proximally to the carpal canal, with the classic longitudinal incision over the carpal canal. The mini-incision technique was shown to be less invasive and equally effective for treating CTS, with less morbidity than with the classic longitudinal incision. PMID:27022592

  5. Optical Coherence Tomography of Clear Corneal Incisions for Cataract Surgery

    PubMed Central

    Schallhorn, Julie M.; Tang, Maolong; Li, Yan; Song, Jonathan C.; Huang, David

    2008-01-01

    Purpose To study the architecture of clear corneal incisions for phacoemulsification cataract surgery using optical coherence tomography (OCT). Setting University-based cornea practice. Methods A prospective study of twenty eyes of twenty patients one month after cataract surgery performed by two experienced surgeons. Temporal clear corneal single-plane incisions were made with 3-mm metal keratomes; five of the twenty eyes received sutures for wound closure. Each eye was scanned before and 1 month after surgery with a prototype high-speed anterior segment OCT system (Carl Zeiss Meditec Inc.). The OCT scans were repeated 3 times during the same visit. The length of the corneal incision, thickness of the cornea, and position of the incision (distance from the external wound edge to the scleral spur) were measured using a computer caliper. The angle of the incision relative to the corneal surface was then calculated. Results The mean corneal incision length was 1.81±0.27mm, the mean corneal thickness at the incision was 747±67µm, and the mean distance between the incision and the scleral spur was 1.46±0.24mm. The average angle of the incision was 26.8±5.5°. The measurements were repeatable to within 0.072mm (pooled standard deviation) for the incision length, 11µm for the corneal thickness, and 0.042mm for the position of the incision. There was no statistically significant difference in any of the parameters between eyes with sutures and those without. Conclusions OCT provides an excellent way to evaluate corneal incisions in cataract surgery postoperatively. Measurements of wound dimensions using OCT are highly repeatable. PMID:18721720

  6. Manual Small Incision Cataract Surgery: A Review.

    PubMed

    Venkatesh, Rengaraj; Chang, David F; Muralikrishnan, Radhakrishnan; Hemal, Kenia; Gogate, Pariskshit; Sengupta, Sabyasachi

    2012-01-01

    We aim at reviewing published peer-reviewed studies that evaluate the safety and efficacy of manual small incision cataract surgery (MSICS). Literature searches of the PubMed and the Cochrane Library databases were conducted with no date restrictions; the searches were limited to articles published in English only. All publications with at least level II and III evidence were studied and surgical techniques were analyzed. MSICS was also compared with phacoemulsification and large incision extracapsular cataract surgery (ECCE) with respect to visual outcome, surgery time, cost, intra and postoperative complications and suitability for high volume surgical practices in the developing world.The overall safety profile of MSICS was found to be excellent with intra and postoperative complication rates comparable to phacoemulsification and ECCE. Multiple studies reported the safety and efficacy of MSICS for complicated cases, such as brunescent and white cataract and cataracts associated with phacolytic and phacomorphic glaucoma. Compared to phacoemulsification MSICS was associated with lower and shorter operative times. Visual outcomes were excellent and comparable to phacoemulsification with up to 6 months follow up.The literature provides outcome analysis of a variety of different MSICS techniques. As a whole, MSICS provides excellent outcomes with a low rate of surgical and postoperative complications. Particularly in the developing world, MSICS appears to provide outcomes that are of comparable quality to phacoemulsification at a much lower cost. PMID:26107133

  7. "Fist, Stick, Knife, Gun": Getting Real in Upward Bound.

    ERIC Educational Resources Information Center

    Pace, Barbara G.; Adkins, Theresa A.

    2002-01-01

    Describes how a teacher found literature for Upward Bound students. Presents Geoffrey Canada's "Fist, Stick, Knife, Gun: A Personal History of Violence in America" as a nonfiction work to provide clarity and connections that might not have been available in a fictional work, yet it had elements of literary fiction that made the text engaging. (SG)

  8. Electromagnetic tracker accuracy in the CyberKnife suite

    NASA Astrophysics Data System (ADS)

    Wilson, Emmanuel; Slack, Rebecca; Banovac, Filip; Dieterich, Sonja; Zhang, Hui; Cleary, Kevin

    2006-03-01

    Electromagnetic trackers have found inroads into medical applications as a tool for navigation in recent years. Their susceptibility to interference from both electromagnetic and ferromagnetic sources have prompted several accuracy assessment studies in past years. To the best of our knowledge, this is the first accuracy study conducted to characterize measurement accuracy of an NDI AURORA electromagnetic tracker within a CyberKnife radiosurgery suite. CyberKnife is a frameless, stereotactic radiosurgery device used to ablate tumors within the brain, spine and in recent years, the chest and abdomen. This paper uses a data collection protocol to collect uniformly distributed data points within a subset of the AURORA measurement volume in a CyberKnife suite. The key aim of the study is to determine the extent to which large metal components of the CyberKnife stereotactic radiosurgery device and robot mount contribute to overall system performance for the AURORA electromagnetic device. A secondary goal of the work is to determine the variation in accuracy and device behavior with the presence of ionizing radiation when the LINAC is turned on.

  9. The Shoemaker's Knife--An Approach of the Polya Type.

    ERIC Educational Resources Information Center

    Libeskind, Shlomo; Lott, Johnny W.

    1984-01-01

    Archimedes' shoemaker's knife problem is interesting in its own right and also allows the demonstration of heuristic teaching ideas and a different method of doing a routine construction. The focus in the article is on the thought processes involved and questions asked when attempting proofs with the problem. (MNS)

  10. 40. Main fuses and knife switch for power to the ...

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

    40. Main fuses and knife switch for power to the bridge, located in the control house. This is one of two located at either end of the main electrical panel (photograph 41). Facing east. - Henry Ford Bridge, Spanning Cerritos Channel, Los Angeles-Long Beach Harbor, Los Angeles, Los Angeles County, CA

  11. Investigation of waste glass pouring behavior over a knife edge

    SciTech Connect

    Ebadian, M.A.

    1998-01-01

    The development of vitrification technology for converting radioactive waste into a glass solid began in the early 1960s. Some problems encountered in the vitrification process are still waiting for a solution. One of them is wicking. During pouring, the glass stream flows down the wall of the pour spout until it reaches an angled cut in the wall. At this point, the stream is supposed to break cleanly away from the wall of the pour spout and fall freely into the canister. However, the glass stream is often pulled toward the wall and does not always fall into the canister, a phenomenon known as wicking. Phase 1 involves the assembly, construction, and testing of a melter capable of supplying molten glass at operational flow rates over a break-off point knife edge. Phase 2 will evaluate the effects of glass and pour spout temperatures as well as glass flow rates on the glass flow behavior over the knife edge. Phase 3 will identify the effects on wicking resulting from varying the knife edge diameter and height as well as changing the back-cut angle of the knife edge. The following tasks were completed in FY97: Design the experimental system for glass melting and pouring; Acquire and assemble the melter system; and Perform initial research work.

  12. Strong alkalinization of Chara cell surface in the area of cell wall incision as an early event in mechanoperception.

    PubMed

    Bulychev, Alexander A; Alova, Anna V; Bibikova, Tatiana N

    2013-11-01

    Mechanical wounding of cell walls occurring in plants under the impact of pathogens or herbivores can be mimicked by cell wall incision with a glass micropipette. Measurements of pH at the surface of Chara corallina internodes following microperforation of cell wall revealed a rapid (10-30s) localized alkalinization of the apoplast after a lag period of 10-20s. The pH increase induced by incision could be as large as 3 pH units and relaxed slowly, with a halftime up to 20min. The axial pH profile around the incision zone was bell-shaped and localized to a small area, extending over a distance of about 100μm. The pH response was suppressed by lowering cell turgor upon the replacement of artificial pond water (APW) with APW containing 50mM sorbitol. Stretching of the plasma membrane during its impression into the cell wall defect is likely to activate the Ca(2+) channels, as evidenced from sensitivity of the incision-induced alkalinization to the external calcium concentration and to the addition of Ca(2+)-channel blockers, such as La(3+), Gd(3+), and Zn(2+). The maximal pH values attained at the incision site (~10.0) were close to pH in light-dependent alkaline zones of Chara cells. The involvement of cytoskeleton in the origin of alkaline patch was documented by observations that the incision-induced pH transients were suppressed by the inhibitors of microtubules (oryzalin and taxol) and, to a lesser extent, by the actin inhibitor (cytochalasin B). The results indicate that the localized increase in apoplastic pH is an early event in mechanoperception and depends on light, cytoskeleton, and intracellular calcium. PMID:23850637

  13. The technical evolution of gamma knife radiosurgery for arteriovenous malformations.

    PubMed

    Lunsford, L Dade; Niranjan, Ajay; Kano, Hideyuki; Kondziolka, Douglas

    2013-01-01

    Gamma Knife stereotactic radiosurgery was first applied for the treatment of an intracranial arteriovenous malformation (AVM) in 1968. Using biplane angiography to target a small-volume, deep-seated lesion, photons were cross-fired on the pathological shunt. The AVM was obliterated within 3 years. This began a cautious introduction of Gamma Knife radiosurgery in the 1970s. As the Gamma Knife technology spread to sites in Europe, South America and the USA in the 1980s, AVM radiosurgery became a primary indication. During the early years the usual standard was to deliver a single radiosurgical isocenter to the target defined by 2-dimensional angiography. Most patients had small-volume AVMs unsuitable for surgical excision. Over time the technique of Gamma Knife AVM surgery evolved to include: careful patient selection, discussion of appropriate treatment strategies, anticonvulsant administration for lobar locations and intraoperative targeting using both high-resolution axial plane imaging--usually magnetic resonance imaging--coupled with biplane digital subtraction angiography. High-speed computer dose planning integrated with more detailed imaging strategies facilitated conformal radiation delivery in a single treatment session coupled with high selectivity of the dose delivered. Multiple isocenters became routine. Long-term follow-up care included serial imaging evaluations to assess the response and to detect complications. Imaging was critical to confirm the desired radiobiological response--complete obliteration. Long-term follow-up after obliteration confirmed that AVM radiosurgery had a high success rate for properly selected patients and a risk-benefit profile that substantiated patient safety. Twenty-year results after Gamma Knife radiosurgery for AVMs are currently available. Established roles have been found for pediatric cases and for larger-volume AVMs unsuitable for surgical removal. The role and technique of embolization prior to radiosurgery continue

  14. Knife mill operating factors effect on switchgrass particle size distributions

    SciTech Connect

    Bitra, V.S.P.; Womac, A.R.; Yang, Y.T.; Igathinathane, C.; Miu, P.I; Chevanan, Nehru; Sokhansanj, Shahabaddine

    2009-06-01

    Biomass particle size impacts handling, storage, conversion, and dust control systems. Switchgrass (Panicum virgatum L.) particle size distributions created by a knife mill were determined for integral classifying screen sizes from 12.7 to 50.8 mm, operating speeds from 250 to 500 rpm, and mass input rates from 2 to 11 kg/min. Particle distributions were classified with standardized sieves for forage analysis that included horizontal sieving motion with machined-aluminum sieves of thickness proportional to sieve opening dimensions. Then, a wide range of analytical descriptors were examined to mathematically represent the range of particle sizes in the distributions. Correlation coefficient of geometric mean length with knife mill screen size, feed rate, and speed were 0.872, 0.349, and 0.037, respectively. Hence, knife mill screen size largely determined particle size of switchgrass chop. Feed rate had an unexpected influence on particle size, though to a lesser degree than screen size. The Rosin Rammler function fit the chopped switchgrass size distribution data with an R2 > 0.982. Mass relative span was greater than 1, which indicated a wide distribution of particle sizes. Uniformity coefficient was more than 4.0, which indicated a large assortment of particles and also represented a well-graded particle size distribution. Knife mill chopping of switchgrass produced strongly fine skewed mesokurtic particles with 12.7 25.4 mm screens and fine skewed mesokurtic particles with 50.8 mm screen. Results of this extensive analysis of particle sizes can be applied to selection of knife mill operating parameters to produce a particular size of switchgrass chop, and will serve as a guide for relations among the various analytic descriptors of biomass particle distributions.

  15. Visualizing morphological changes of clear corneal cataract incisions with optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Rao, Bin; Zhang, Jun; Taban, Mehran; McDonnell, Peter J.; Chen, Zhongping

    2004-07-01

    Dynamic morphological changes of clear corneal cataract incisions are studied with Optical Coherence Tomography (OCT). Two opposite types of dynamic incision wound behaviors are documented. A stable incision angle range is found to be existent for single-planed, clear corneal cataract incisions. When well pressurized, incision angles within this stable range result in well-apposed incision edges that resist gapping while incision angles falling outside this range have a larger tendency for wound leakage. It is also shown that a two-planed incision can effectively expand the stable range. For incision angles outside the stable range, the farther the incision angle is away from stable range, the larger the gap between incision wound edges when well pressurized. Thus, incision construction method has a major impact on the self-sealing capability of the incision wounds. In this investigation, OCT has been demonstrated as an effective modality for imaging and monitoring corneal surgery.

  16. Detrital Zircon Record of Colorado River Incision

    NASA Astrophysics Data System (ADS)

    Kimbrough, D.; Grove, M.; Gehrels, G.; Dorsey, R.; House, K. P.; Howard, K.; Pearthree, P. A.; Spencer, J. E.; Mahoney, B.

    2007-05-01

    The Colorado River is a large, youthful, unequilibrated continental drainage system the base-level for which was established rather abruptly between 5 and 6 million years ago in conjunction with Gulf of California rifting and establishment of the modern river course through the western Grand Canyon and lower Colorado river region. New laser ablation ICPMS detrital zircon U-Pb analyses (~3000) from ~40 samples provide insight into details relating to the cause, timing and consequences of river inception. These samples encompass (1) the modern Colorado River delta, (2) major tributaries including the Green, "Grand", San Juan, Little Colorado and Gila rivers (3) late Miocene to Pliocene sediments along the lower Colorado (4) late Miocene to Pleistocene deltaic and fluvial sediments of the Imperial and Palm Spring Groups in the western Salton Trough, and (5) late Miocene- early Pliocene Bidahochi Formation of eastern Arizona. Data from the western Salton Trough and modern delta yield strata yield remarkably homogeneous age distributions that indicate there was little evolution in Colorado River sediment composition since 5.3 Ma. Detrital zircon is dominated by a mix of local southwest US cratonal basement (1.7 and 1.4 Ga) plus reworked supracrustal sequences of the Colorado Plateau that provide Neoproterozoic, 1.1 Ga, and early Paleozoic zircons. A relative paucity of Grenville-age grains in the earliest part of the delta sequence may reflect an early stage of the modern river prior to deep incision through Colorado Plateau erg deposits. The strong homogeneity of the detrital zircon record from late Miocene to the present is consistent with the `lake spillover model' for inception and integration of the modern Colorado River drainage. Abrupt integration of the lower Colorado River after 5.6 Ma is clearly recorded by detrital zircon ages from the laucustrine Bouse Formation and Bullhead alluvium aggradational package. Fluvial-laucustrine deposits of the Bidahochi

  17. Comparison of O-Type HybridKnife to Conventional Knife in Endoscopic Submucosal Dissection for Gastric Mucosal Lesions

    PubMed Central

    Huang, Rui; Yan, Honglin; Ren, Gui; Pan, Yanglin; Zhang, Linhui; Liu, Zhiguo; Guo, Xuegang; Wu, Kaichun

    2016-01-01

    Abstract Endoscopic submucosal dissection (ESD) has been accepted as a minimal invasive alternative to surgery for localized superficial gastrointestinal neoplasms recently. However, the procedure remains to be technically challenging and time consuming. A new dissecting knife with partially insulated tip has been recently developed with built-in injection capability. The purpose of this study was to investigate whether the efficiency of ESD procedure could be improved with this new device. A total of 78 patients, who underwent ESD with gastric mucosal lesions including flat type polyps, adenoma or early gastric cancer, were randomly assigned to either ESD with O-type HybridKnife or conventional ESD knives without waterjet. Procedure time and related factors of ESD were analyzed. ESD procedure time was 43.0 (interquartile range, IQR 27.0–60.0) minutes in HybridKnife group compared to 60.5 (IQR 44.0–86.3) minutes in the control group (P = 0.001). There was no difference in the clinical outcome and the adverse event rate. The former demonstrated more favorable results in lesions ≤4 cm of specimen size (P ≤ 0.0001) and when located in the distal stomach (P = 0.001), also in lesions with fibrosis (P = 0.008). Multivariate regression analysis showed that O-type Knife (P ≤ 0.0001), specimen size (P ≤ 0.0001), and fibrosis (P ≤ 0.0001) were independent predictors of procedure time. The O-type HybridKnife yielded faster procedure time compared to the conventional knives in gastric ESD with a similar safety profile. PMID:27043675

  18. Comparison of O-Type HybridKnife to Conventional Knife in Endoscopic Submucosal Dissection for Gastric Mucosal Lesions.

    PubMed

    Huang, Rui; Yan, Honglin; Ren, Gui; Pan, Yanglin; Zhang, Linhui; Liu, Zhiguo; Guo, Xuegang; Wu, Kaichun

    2016-03-01

    Endoscopic submucosal dissection (ESD) has been accepted as a minimal invasive alternative to surgery for localized superficial gastrointestinal neoplasms recently. However, the procedure remains to be technically challenging and time consuming. A new dissecting knife with partially insulated tip has been recently developed with built-in injection capability. The purpose of this study was to investigate whether the efficiency of ESD procedure could be improved with this new device. A total of 78 patients, who underwent ESD with gastric mucosal lesions including flat type polyps, adenoma or early gastric cancer, were randomly assigned to either ESD with O-type HybridKnife or conventional ESD knives without waterjet. Procedure time and related factors of ESD were analyzed. ESD procedure time was 43.0 (interquartile range, IQR 27.0-60.0) minutes in HybridKnife group compared to 60.5 (IQR 44.0-86.3) minutes in the control group (P = 0.001). There was no difference in the clinical outcome and the adverse event rate. The former demonstrated more favorable results in lesions ≤4 cm of specimen size (P ≤ 0.0001) and when located in the distal stomach (P = 0.001), also in lesions with fibrosis (P = 0.008). Multivariate regression analysis showed that O-type Knife (P ≤ 0.0001), specimen size (P ≤ 0.0001), and fibrosis (P ≤ 0.0001) were independent predictors of procedure time. The O-type HybridKnife yielded faster procedure time compared to the conventional knives in gastric ESD with a similar safety profile. PMID:27043675

  19. Modeling the Evolution of Incised Streams: III. Model Application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Incision and ensuing widening of alluvial stream channels is widespread in the midsouth and midwestern United States and represents an important form of channel adjustment. Two accompanying papers have presented a robust computational model for simulating the long-term evolution of incised and resto...

  20. The stream channel incision syndrome and water quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Watershed development often triggers channel incision, which accounts for 60-90% of sediments leaving many disturbed watersheds. Impacts of such incision on water quality processes and the implication of such impairment on stream biota are relevant to issues associated with establishing total maxim...

  1. Wound Hypoxia in Deep Tissue after Incision in the Rats

    PubMed Central

    Kang, Sinyoung; Lee, Dongchul; Theusch, Brett E.; Arpey, Christopher J.; Brennan, Timothy J.

    2013-01-01

    Our previous studies using rat models of incisional pain have demonstrated that tissue lactate levels increase and pH decreases for several days after incision, suggesting the presence of an ischemic-like condition. The purpose of this study was to evaluate the time course and the extent of tissue hypoxia that develops in incised muscle and skin. We directly measured oxygen tension at several time points after incisions of the gastrocnemius muscle, the paraspinal skin, and the plantar hindpaw in anesthetized rats using an oxygen-sensitive microelectrode. In vivo hypoxia of the incised tissues was also evaluated immunohistochemically using a hypoxia marker pimonidazole hydrochloride. To minimized inter-subject variability, unincised contralateral tissues were used as a control. Tissue oxygen tension was decreased in both skeletal muscle and skin compared to control, for several days after incision: when measured directly, oxygen tension decreased immediately and remained low for several days after incisions. Pimonidazole immunostaining revealed hypoxic areas in incised muscle and skin for several days. By postoperative day 10, tissue oxygen tension recovered to that of control tissue. These results support the evidence that a hypoxic condition is present in deep tissue after incisions and that an ischemic-like mechanism may contribute to postoperative pain. PMID:23926943

  2. Single-incision laparoscopic sigmoidectomy and rectopexy case series.

    PubMed

    Adair, James; Gromski, Mark A; Nagle, Deborah

    2011-08-01

    Single-incision laparoscopic surgery has recently been investigated as a novel approach to colorectal pathology. This article describes 3 cases of single-incision laparoscopic sigmoidectomy with rectopexy for the treatment of rectal prolapse. We demonstrate our surgical approach and results from these initial patients treated with this novel technique. PMID:21810504

  3. Incision into the eastern Andean Plateau during Pliocene cooling.

    PubMed

    Lease, Richard O; Ehlers, Todd A

    2013-08-16

    Canyon incision into mountain topography is commonly used as a proxy for surface uplift driven by tectonic or geodynamic processes, but climatic changes can also instigate incision. The ~1250-kilometer (km)-long eastern margin of the Andean Plateau hosts a series of 1.5- to 2.5-km-deep canyons that cross major deformation zones. Using (U-Th)/He thermochronology, we document a transition from Miocene faulting to Pliocene canyon incision across the northeastern plateau margin. Regionally, widespread Pliocene incision into the eastern plateau margin is concurrent with a shift in global climate from early Pliocene warmth to late Pliocene cooling. Enhanced moisture transport onto the Andean Plateau driven by sea surface temperature changes during cooling is the likely pacemaker for canyon incision. PMID:23950534

  4. First Canadian experience with robotic single-incision pyeloplasty: Comparison with multi-incision technique

    PubMed Central

    Law, Jeffrey; Rowe, Neal; Archambault, Jason; Nastis, Sofia; Sener, Alp; Luke, Patrick P.

    2016-01-01

    Introduction: We compared the outcomes of single-incision, robot-assisted laparoscopic pyeloplasty vs. multiple-incision pyeloplasty using the da Vinci robotic system. Methods: We reviewed all consecutive robotic pyeloplasties by a single surgeon from January 2011 to August 2015. A total of 30 procedures were performed (16 single:14 multi-port). Two different single-port devices were compared: the GelPort (Applied Medical, Rancho Santa Margarita, CA) and the Intuitive single-site access port (Intuitive Surgical, Sunnyvale, CA). Results: Patient demographics were similar between the two groups. Mean operating time was similar among the single and multi-port groups (225.2 min vs. 198.9 minutes [p=0.33]). There was no significant difference in length of hospital stay in either group (86.2 hr vs. 93.2 hr [p=0.76]). There was no difference in success rates or postoperative complications among groups. Conclusions: Single-port robotic pyeloplasty is non-inferior to multiple-incision robotic surgery in terms of operative times, hospitalization time, success rates, and complications. Verifying these results with larger cohorts is required prior to the wide adoption of this technique. Ongoing objective measurements of cosmesis and patient satisfaction are being evaluated. PMID:27217850

  5. Influence of Incision Location on Transmitter Loss, Healing, Incision Lengths, Suture Retention, and Growth of Juvenile Chinook Salmon

    SciTech Connect

    Panther, Jennifer L.; Brown, Richard S.; Gaulke, Greggory L.; Woodley, Christa M.; Deters, Katherine A.

    2010-05-11

    In this study, conducted by Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers, Portland District, we measured differences in survival and growth, incision openness, transmitter loss, wound healing, and erythema among abdominal incisions on the linea alba, lateral and parallel to the linea alba (muscle-cutting), and following the underlying muscle fibers (muscle-sparing). A total of 936 juvenile Chinook salmon were implanted with both Juvenile Salmon Acoustic Tracking System transmitters (0.43 g dry) and passive integrated transponder tags. Fish were held at 12°C (n = 468) or 20°C (n = 468) and examined once weekly over 98 days. We found survival and growth did not differ among incision groups or between temperature treatment groups. Incisions on the linea alba had less openness than muscle-cutting and muscle-sparing incisions during the first 14 days when fish were held at 12°C or 20°C. Transmitter loss was not different among incision locations by day 28 when fish were held at 12°C or 20°C. However, incisions on the linea alba had greater transmitter loss than muscle-cutting and muscle-sparing incisions by day 98 at 12°C. Results for wound closure and erythema differed among temperature groups. Results from our study will be used to improve fish-tagging procedures for future studies using acoustic or radio transmitters.

  6. A noninvasive eye fixation monitoring system for CyberKnife radiotherapy of choroidal and orbital tumors

    SciTech Connect

    Daftari, I. K.; Petti, P. L.; Larson, D. A.; O'Brien, J. M.; Phillips, T. L.

    2009-03-15

    A new noninvasive monitoring system for fixing the eye has been developed to treat orbital and choroidal tumors with CyberKnife-based radiotherapy. This device monitors the eye during CT/MRI scanning and during treatment. The results of this study demonstrate the feasibility of the fixation light system for CyberKnife-based treatments of orbital and choroidal tumors and supports the idea that larger choroidal melanomas and choroidal metastases could be treated with CyberKnife without implanting fiducial markers.

  7. Testing bedrock incision models: Holocene channel evolution, High Cascades, Oregon

    NASA Astrophysics Data System (ADS)

    Sweeney, K. E.; Roering, J. J.; Fonstad, M. A.

    2013-12-01

    There is abundant field evidence that sediment supply controls the incision of bedrock channels by both protecting the bed from incision and providing tools to incise the bed. Despite several theoretical models for sediment-dependent bedrock abrasion, many investigations of natural channel response to climatic, lithologic, or tectonic forcing rely on the stream power model, which does not consider the role of sediment. Here, we use a well-constrained fluvial channel cut into a Holocene lava flow in the High Cascades, Oregon to compare incision predictions of the stream power model and of the full physics of theoretical models for saltation-abrasion incision by bedload and suspended load. The blocky andesite of Collier lava flow erupted from Collier Cone ~1500 years ago, paving over the existing landscape and erasing fine-scale landscape dissection. Since the eruption, a 6 km stream channel has been incised into the lava flow. The channel is comprised of three alluvial reaches with sediment deposits up to 2 m thick and two bedrock gorges with incision of up to 8 m, with larger magnitude incision in the upstream gorge. Abraded forms such as flutes are present in both gorges. Given the low magnitude and duration of modern snowmelt flow in the channel, it is likely that much of the incision was driven by sediment-laden outburst floods from the terminus of Collier Glacier, which is situated just upstream of the lava flow and has produced two outburst floods in the past 100 years. This site is well suited for comparing incision models because of the relatively uniform lithology of the lava flow and our ability to constrain the timing and depth of incision using the undissected lava surface above the channel as an initial condition. Using a simple finite difference scheme with airborne-Lidar-derived pre-incision topography as an initial condition, we predict incision in the two gorges through time with both stream power and sediment-dependent models. Field observations

  8. A Simple Approach to Specimen Retrieval via Posterior Colpotomy Incision

    PubMed Central

    Menderes, Gulden; Tower, Amanda M.; Silasi, Dan-Arin; Azodi, Masoud

    2015-01-01

    Introduction: Posterior colpotomy incision for specimen retrieval is infrequently used in gynecologic laparoscopic surgery unless a concomitant hysterectomy is performed. We aim to describe a simple and unique technique for creating the colpotomy incision and to describe intraoperative and postoperative outcomes. Methods: Fifty patients underwent adnexal specimen retrieval through a posterior colpotomy incision. After devascularization and detachment of the adnexal specimen, the posterior cul-de-sac was visualized. The colpotomy incision was created by introducing a 12- or 15-mm laparoscopic trocar through the vagina into the posterior vaginal fornix under direct visualization. Specimens were placed into laparoscopic bags and removed through the vagina. The colpotomy incision was closed vaginally. Charts were reviewed for intraoperative and postoperative outcomes. Results: Twenty-nine women underwent adnexal surgery for an adnexal mass, 14 women underwent surgery for pelvic pain, and 7 women underwent adnexal surgery for primary prevention of malignancy. The specimens removed ranged in size from 2 to 16 cm (mean 5.7). The mean time patients were under anesthesia was 103 minutes (SD 57.3). There were no operative complications related to the colpotomy incision and no cases of postoperative vaginal cellulitis or pelvic infection were reported. Only 1 woman with a prior vaginal delivery reported dyspareunia postoperatively. Conclusion: This simple technique for posterior colpotomy incision can easily be added to the gynecologic surgeon's armamentarium and can be safely used for most women. PMID:25901107

  9. Development of knife-edge ridges on ion-bombarded surfaces

    NASA Astrophysics Data System (ADS)

    Holmes-Cerfon, Miranda; Zhou, Wei; Bertozzi, Andrea L.; Brenner, Michael P.; Aziz, Michael J.

    2012-10-01

    We demonstrate in both laboratory and numerical experiments that ion bombardment of a modestly sloped surface can create knife-edge like ridges with extremely high slopes. Small pre-fabricated pits expand under ion bombardment, and the collision of two such pits creates knife-edge ridges. Both laboratory and numerical experiments show that the pit propagation speed and the precise shape of the knife edge ridges are universal, independent of initial conditions, as has been predicted theoretically. These observations suggest a method of fabrication in which a surface is pre-patterned so that it dynamically evolves to a desired target pattern made of knife-edge ridges.

  10. A knife-edge array field emission cathode

    SciTech Connect

    Lee, B.

    1994-08-01

    many cathode applications require a new type of cathode that is able to produce short pulsed electron beams at high emission current. Gated field emitter arrays of micrometer size are recognized as candidates to meet this need and have become the research focus of vacuum microelectronics. Existing fabrication methods produce emitters that are limited either in frequency response or in current emission. One reason is that the structure of these emitters are not sufficiently optimized. In this study, the author investigated the factors that affect the performance of field emitters. An optimum emitter structure, the knife-edge field emitter array, was developed from the analysis. Large field enhancement factor, large effective emission area, and small emitter capacitance are the advantages of the structure. The author next explored various options of fabricating the knife-edge emitter structure. He proposed a unique thin film process procedure and developed the fabrication techniques to build the emitters on (110) silicon wafers. Data from the initial cathode tests showed very low onset voltages and Fowler-Nordheim type emission. Emission simulation based on the fabricated emitter structure indicated that the knife-edge emitter arrays have the potential to produce high performance in modulation frequency and current emission. Several fabrication issues that await further development are discussed and possible solutions are suggested.

  11. Therapeutic advances: Single incision laparoscopic hepatopancreatobiliary surgery

    PubMed Central

    Chang, Stephen Kin Yong; Lee, Kai Yin

    2014-01-01

    Single-port laparoscopic surgery (SPLS) is proposed to be a step towards minimizing the invasiveness of surgery, and has since gained popularity in several surgical sub-specialties including hepatopancreatobiliary surgery. SPLS has since been applied to cholecystectomy, liver resection as well as pancreatectomy for a multitude of pathologies. Benefits of SPLS over conventional multi-incision laparoscopic surgery include improved cosmesis and potentially post-operative pain at specific time periods and extra-umbilical sites. However, it is also associated with longer operating time, increased rate of complications, and increased rate of port-site hernia. There is no significant difference between length of hospital stay. SPLS has a significant learning curve that affects operating time, rate of conversion and rate of complications. In this article, we review the literature on SPLS in hepatobiliary surgery - cholecystectomy, hepatectomy and pancreatectomy, and offer tips on overcoming potential technical obstacles and minimizing the complications when performing SPLS - surgeon position, position of port and instruments, instrument crossing position, standard hand grip vs reverse hand grip, snooker cue guide position, prevention of incisional hernia. SPLS is a promising direction in laparoscopic surgery, and we recommend step-wise progression of applications of SPLS to various hepatopancreatobiliary surgeries to ensure safe adoption of the surgical technique. PMID:25339820

  12. Direct measures of mechanical energy for knife mill size reduction

    SciTech Connect

    Bitra, V.S.P.; Womac, A.R.; Igathinathane, C.; Miu, P.I; Yang, Y.T.; Smith, D.R.; Chevanan, Nehru; Sokhansanj, Shahabaddine

    2009-08-01

    Lengthy straw/stalk of biomass may not be directly fed into grinders such as hammer mills and disc refiners. Hence, biomass needs to be preprocessed using coarse grinders like a knife mill to allow for efficient feeding in refiner mills without bridging and choking. Size reduction mechanical energy was directly measured for switchgrass (Panicum virgatum L.), wheat straw (Triticum aestivum L.), and corn stover (Zea mays L.) in an instrumented knife mill. Direct power inputs were determined for different knife mill screen openings from 12.7 to 50.8 mm, rotor speeds between 250 and 500 rpm, and mass feed rates from 1 to 11 kg/min. Overall accuracy of power measurement was calculated to be 0.003 kW. Total specific energy (kWh/Mg) was defined as size reduction energy to operate mill with biomass. Effective specific energy was defined as the energy that can be assumed to reach the biomass. The difference is parasitic or no-load energy of mill. Total specific energy for switchgrass, wheat straw, and corn stover chopping increased with knife mill speed, whereas, effective specific energy decreased marginally for switchgrass and increased for wheat straw and corn stover. Total and effective specific energy decreased with an increase in screen size for all the crops studied. Total specific energy decreased with increase in mass feed rate, but effective specific energy increased for switchgrass and wheat straw, and decreased for corn stover at increased feed rate. For knife mill screen size of 25.4 mm and optimum speed of 250 rpm, optimum feed rates were 7.6, 5.8, and 4.5 kg/min for switchgrass, wheat straw, and corn stover, respectively, and the corresponding total specific energies were 7.57, 10.53, and 8.87 kWh/Mg and effective specific energies were 1.27, 1.50, and 0.24 kWh/Mg for switchgrass, wheat straw, and corn stover, respectively. Energy utilization ratios were calculated as 16.8%, 14.3%, and 2.8% for switchgrass, wheat straw, and corn stover, respectively. These

  13. MTF measurement of IRFPA based on double-knife edge scanning method

    NASA Astrophysics Data System (ADS)

    Ying, Cheng-ping; Wu, Bin; Wang, Heng-fei; Shi, Xue-shun; Liu, Hong-yuan

    2013-09-01

    Modulation transfer function (MTF) is one of the most important parameters of infrared focal plane array (IRFPA). A double-knife edge scanning method is proposed for MTF measurement of IRFPA. In this method, a double-knife edge was used as a target, and the IRFPA under test was positioned in the focal plane of the imaging optical system by a 3-axis translation stage. With an IRFPA data acquisition system, the image of the double-knife edge was restored. By scanning in the direction orthogonal to the double-knife edge image, edge spread function (ESF) curve of each pixel swept across the knife-edge image was obtained. MTF could be calculated from the subsequent fitting, differential and Fourier transformation procedures. With double-knife edge scanning, two ESF curves of double-knife edge were obtained simultaneously, and symmetry of the two ESF curves could be used to evaluate the verticality between photosensitive surface of IRFPA and optical axis of the double-knife edge imaging system. In addition, this method can be used to judge the existing of interference from outside such as vibration, stray light and electrical noise. A measurement facility for IRFPA's MTF based on double-knife edge scanning method was also established in this study. The facility is composed of double-knife edge imaging optical system, 3-axis translation stage and data acquisition system, et al. As the kernel of the facility, the double-knife edge imaging optical system mainly comprises two symmetrical parabolic mirrors coating with reflective material, and the magnification of the optical system is 1 with an operation wavelength range of (1˜14) μm.

  14. 11. REPRESENTATIVE DETAIL VIEW OF RAILING (INCISED PATTERN IS USED ...

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

    11. REPRESENTATIVE DETAIL VIEW OF RAILING (INCISED PATTERN IS USED ON BOTH SIDES OF THE PARAPET) - Central of Georgia Railway, Bay Street Viaduct, U.S. 17 & Bay Street, spanning Central of Georgia Railroad, Savannah, Chatham County, GA

  15. Single-Incision Laparoscopic Combined Cholecystectomy and Appendectomy

    PubMed Central

    Chen, Yongsheng; Kong, Jing

    2014-01-01

    Background and Objectives: Single-incision laparoscopic surgery is becoming more widely used, but few combined procedures have been reported. Herein we share our experience with single-incision laparoscopic combined cholecystectomy and appendectomy. Methods: We reviewed data from 26 patients who underwent single-incision laparoscopic combined cholecystectomy and appendectomy between May 1, 2009 and June 1, 2013 at Shengjing Hospital. All the procedures were performed with conventional laparoscopic instruments placed through a single operating portal of entry created within the umbilicus. Results: All the operations were successfully completed without conversion to conventional laparoscopic or open surgery. No intraoperative complications occurred. Patients were satisfied with the therapeutic and cosmetic outcomes. Conclusions: Single-incision laparoscopic combined cholecystectomy and appendectomy appear to be a technically feasible alternative to the standard laparoscopic procedure in simultaneous management of coexisting benign gallbladder and appendix pathologies. Larger studies are required to confirm these findings. PMID:25392641

  16. Cyclic steps incised on experimental bedrock

    NASA Astrophysics Data System (ADS)

    Yokokawa, M.; Kyogoku, A.; Kotera, A.; Izumi, N.

    2013-12-01

    the step shape has been predicted by the mathematical model (Izumi et al., 2012). Among three cases of sediment supply: 1 g/sec, 3 g/sec, and 6 g/sec with fixed water discharge (52 g/sec), the erosion rate was maximized in the cases of the sediment supply of 3 g/sec both in the cement-sand-water ratios of 2:150:50 and 3:150:50. The erosion rate is higher in the case of the moderate amount of sediment supply rather than in the case of the largest amount of sediment supply in which the alluvial cover effect inhibited erosion. This result is consistent with that observed in previous studies (Sklar & Dietrich, 2004; Johnson & Whipple, 2010). References Izumi, N., Yokokawa, M. & Parker G. 2012. Cyclic step morphology formed on bedrock. Annual Journal of Hydraulic Engineering 68(4) : I_955-I_960. Johnson, J.P.L. & Whipple, K.X. 2010. Evaluating the controls of shear stress, sediment supply, alluvial cover, and channel morphology on experimental bedrock incision rate. Journal of Geophysical Research 115, F02018, doi:10.1029/2009JF001335. Sklar, L.S. & Dietrich, W.E. 2004. A mechanistic model for river incision into bedrock by sultating bedload. Water Resources Re-search 40, W06301, doi:10.1029/2003WR002496.

  17. Incision of the Colorado River in southern Utah - insights from channel profiles, local incision rates, and modeling of lithologic controls

    NASA Astrophysics Data System (ADS)

    Cook, K.; Whipple, K.; Heimsath, A.

    2009-04-01

    The Colorado River and its tributaries in southern Utah and northern Arizona provide an opportunity to study the propagation of bedrock incision through a large heterogeneous fluvial network, as the system is continuing to adjust to the baselevel fall responsible for the Grand Canyon. Although the carving of the Grand Canyon was largely complete by ~1 Ma, the canyon ends at Lee's Ferry and the incision history of Colorado River system upstream of the associated large knickpoint has been the subject of debate. In conjunction with existing incision rate estimates based on the dating of strath terraces, we use longitudinal profiles of the Colorado and tributaries between Marble Canyon and Cataract Canyon to investigate the incision history of the Colorado in this region. We find that all but two of the tributaries in this region steepen as they enter the Colorado River. The consistent presence of oversteepened reaches with similar elevation drops in the lower section of these channels, and their coincidence within a corridor of high local relief along the Colorado, suggest that the tributaries are steepening in response to an episode of increased incision rate on the Colorado River. This analysis is supported by available incision rate data, as the spatial distribution of incision rates predicted by the channel profiles is consistent with existing rate estimates. The two analyzed tributaries that show no evidence for this incision pulse, Trachyte Creek and Bullfrog Creek, have smoothly concave profiles and do not contain knickpoints. In order to evaluate the significance of these anomalous channel profiles, we measure in situ 10Be concentrations on four gravel-covered strath surfaces elevated from 1 m to 110 m above Trachyte Creek. The surfaces yield exposure ages that range from approximately 2.5 ka to 267 ka and suggest incision rates that vary between 350 and 600 m/my. These incision rates are similar to other rates determined within the high-relief corridor, and

  18. Orchiopexy through a single high transverse scrotal incision

    PubMed Central

    Khirallah, Mohammad G.; Elafifi, Mahmoud A.; Elbatarny, Akram M.; Elsharaby, Ahmed M.

    2015-01-01

    Background: Palpable Undescended Testis (PUT) represents a common paediatric problem in many premature and some mature infants. There are several surgical techniques to correct PUT either through combined inguinal and scrotal incision or single transverse scrotal incision. This study assessed single high transverse scrotal incision for the management of PUT as regards to feasibility, postoperative success and final cosmetic results. Materials and Methods: One hundred twenty patients were managed at the Paediatric Surgery Department of Tanta University Hospital with PUT during the period from March 2010 to March 2014. They were all operated at the age of 6-12 months. We excluded recurrent cases, and cases older than 12 months. Through high transverse scrotal incision, the layers were divided, and the canal entered through the external ring, dissecting the PUT and bringing it through the incision. Hernia sac, if present, was ligated at the neck. Creation of the dartos pouch was then made through the same incision. All infants were followed-up at 1 month, 2 months and 6 months to detect any re-ascended cases, testicular atrophy and the final cosmetic appearance. Results: A total of 140 PUTs were operated upon in 120 patients. PUT was bilateral in 20 patients, right-sided in 65 cases and left-sided in 35 cases. Thirty testes were located at the external ring; the others were located within the inguinal canal. No cases needed a redo operation, and there was no case of postoperative testicular atrophy. Conclusion: Single high transverse incision was sufficient to deal with PUT especially, in young infants (age 6 months) with no need for conversion in most cases to the traditional two incisions technique, and good long term follow-up and a better cosmetic results. PMID:25659553

  19. Differential stream incision in the Oregon Coast Range

    SciTech Connect

    Personius, S.F. )

    1993-04-01

    Stream incision rates are used to determine rates and styles of late quaternary deformation of the Oregon Coast Range, in the forearc of the Cascadia subduction zone. Bedrock incision rates were obtained along westward-flowing streams, from the Umpqua river in a central western Oregon to the North Fork Nehalem River in northwestern Oregon. Incision measurements were restricted mostly to nontidal reaches that are more than 20--40 km inland from the coast, to exclude areas affected by eustatic changes in sea level. Most strath ages were determined indirectly by radiocarbon dating of detrital charcoal sampled from alluvium that overlies the straths. A few incision measurements were made on straths that underlie higher, less well preserved terrace remnants. The ages of some of these higher straths were determined by thermoluminescence (TL) dating. These ages are less constrained than those established with radiocarbon dating, but they appear to yield similar rates of incision. The difference in age between the overlying sediments and the age of strath abandonment is unknown, but several lines of evidence indicate that sediment mobilization and deposition most likely were concurrent with cutting of the strath. Numerous strath height measurements indicate that rates of incision are fairly uniform along many kilometers of individual Coast Range streams, regardless of the type of bedrock traversed. Such uniform incision rates do not support the landward tilting of the Coast Range as postulated by other studies. However, regional differences in incision apparent in northern Oregon may be explained by differential uplift caused by north-south compression in the overriding North American plate, or by changes in the geometry of the subducting Juan de Fuca plate.

  20. Tensile Properties of the Murine Ventral Vertical Midline Incision

    PubMed Central

    Carlson, Mark A.; Chakkalakal, Dennis

    2011-01-01

    Background In clinical surgery, the vertical midline abdominal incision is popular but associated with healing failures. A murine model of the ventral vertical midline incision was developed in order to study the healing of this incision type. Methodology/Principal Findings The strength of the wild type murine ventral abdominal wall in the midline was contained within the dermis; the linea alba made a negligible contribution. Unwounded abdominal wall had a downward trend (nonsignificant) in maximal tension between 12 and 29 weeks of age. The incision attained 50% of its final strength by postoperative day 40. The maximal tension of the ventral vertical midline incision was nearly that of unwounded abdominal wall by postwounding day 60; there was no difference in unwounded vs. wounded maximal tension at postwounding day 120. Conclusions/Significance After 120 days of healing, the ventral vertical midline incision in the wild type mouse was not significantly different from age-matched nonwounded controls. About half of the final incisional strength was attained after 6 weeks of healing. The significance of this work was to establish the kinetics of wild type incisional healing in a model for which numerous genotypes and genetic tools would be available for subsequent study. PMID:21915298

  1. [Incisions for biaxial and coaxial microincision cataract surgery].

    PubMed

    Müller, M; Kohnen, T

    2010-02-01

    Microincision cataract surgery (MICS) represents a new level in the development of cataract surgery. Phacoemulsification with intraocular lens (IOL) implantation via incisions of incision cataract surgery, the advantages of MICS are less corneal astigmatism and fewer corneal surface irregularities, with favorable implications for visual quality and early rehabilitation. In the effort toward smaller incisions, special interest should be given to wound integrity, especially regarding the risk of endophthalmitis. With limited corneal elastic capacity, irreversible expansion of the incision with tissue laceration may occur. Smaller incisions are superior only if they cause less trauma. This requires an optimized relationship between incision size and manipulation during IOL implantation as well as attention to safety issues. MICS offers a platform for new benchmarks in phacoemulsification. PMID:20107810

  2. A geometric analysis of mastectomy incisions: Optimizing intraoperative breast volume

    PubMed Central

    Chopp, David; Rawlani, Vinay; Ellis, Marco; Johnson, Sarah A; Buck, Donald W; Khan, Seema; Bethke, Kevin; Hansen, Nora; Kim, John YS

    2011-01-01

    INTRODUCTION: The advent of acellular dermis-based tissue expander breast reconstruction has placed an increased emphasis on optimizing intraoperative volume. Because skin preservation is a critical determinant of intraoperative volume expansion, a mathematical model was developed to capture the influence of incision dimension on subsequent tissue expander volumes. METHODS: A mathematical equation was developed to calculate breast volume via integration of a geometrically modelled breast cross-section. The equation calculates volume changes associated with excised skin during the mastectomy incision by reducing the arc length of the cross-section. The degree of volume loss is subsequently calculated based on excision dimensions ranging from 35 mm to 60 mm. RESULTS: A quadratic relationship between breast volume and the vertical dimension of the mastectomy incision exists, such that incrementally larger incisions lead to a disproportionally greater amount of volume loss. The vertical dimension of the mastectomy incision – more so than the horizontal dimension – is of critical importance to maintain breast volume. Moreover, the predicted volume loss is more profound in smaller breasts and primarily occurs in areas that affect breast projection on ptosis. CONCLUSIONS: The present study is the first to model the relationship between the vertical dimensions of the mastectomy incision and subsequent volume loss. These geometric principles will aid in optimizing intra-operative volume expansion during expander-based breast reconstruction. PMID:22654531

  3. Water table fluctuations near an incised stream, Walnut Creek, Iowa

    USGS Publications Warehouse

    Schilling, K.E.; Zhang, Y.-K.; Drobney, P.

    2004-01-01

    Incised channels are common features in many agricultural watersheds, but the effects of channel incision on riparian water table conditions have been poorly documented. In this study, we evaluate the water table fluctuations in the floodplain near an incised stream (Walnut Creek, Iowa) and investigate the roles that channel incision and variable recharge play in modifying the water table configuration in the floodplain. Groundwater flows from higher landscape positions towards Walnut Creek under hydraulic gradients that were steepest near the upland/floodplain contact and in the near-stream riparian zone. Annually, water table fluctuations on the floodplain were greatest in wells located 30 m from the creek, midway between the creek and upland. Water levels monitored continuously during a runoff event indicated that bank storage was confined to a narrow zone adjacent to the channel. A steady-state, one-dimensional analytical model was developed to describe the shape of the water table surface near an incised stream and evaluate how variable groundwater recharge and channel bed lowering has affected the shape of the water table surface. Results from this study have implications for managing the riparian buffers of incised streams with successful establishment dependent upon matching buffer vegetation to riparian water table conditions. ?? 2003 Elsevier B.V. All rights reserved.

  4. Two-dimensional light-distribution measurement with a 90 deg cornered knife edge

    NASA Astrophysics Data System (ADS)

    Pernick, B. J.

    1993-07-01

    An aperture-scanning technique for determining a two-dimensional light distribution is described. Results are obtained by moving a wedge-shaped, knife-edge aperture and comparing measurements from adjacent scans. The scanning procedure described herein overcomes deficiencies inherent in alternative methods that use a two-dimensional detector array or one-dimensional motion of a knife-edge aperture.

  5. Study of internal energy flows in dipole vortex beams by knife edge test

    NASA Astrophysics Data System (ADS)

    Singh, Brijesh Kumar; Bahl, Monika; Mehta, Dalip Singh; Senthilkumaran, Paramasivam

    2013-04-01

    The rotation of Poynting vector in dipole vortex beam (DVB) during propagation has been experimentally detected in a knife edge test. The dipole vortex beam is generated, when a collimated laser beam is incident on a phase mask, displayed on spatial light modulator (SLM) in reflection mode. The knife edge test reveals dipole configurations through strikingly distinct intensity intrusions in the geometrical shadow region.

  6. Removing seed coat fragments with a lint cleaner grid bar air knife

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seed coat fragments (SCF) in ginned lint cause spinning problems at the textile mill and undesirable defects in finished goods. Work continued on developing an air knife that may help remove SCF from ginned lint. The air knife is mounted on the 1st lint cleaner grid bar of a saw-type lint cleaner,...

  7. Gamma Knife 3-D dose distribution near the area of tissue inhomogeneities by normoxic gel dosimetry

    SciTech Connect

    Isbakan, Fatih; Uelgen, Yekta; Bilge, Hatice; Ozen, Zeynep; Agus, Onur; Buyuksarac, Bora

    2007-05-15

    The accuracy of the Leksell GammaPlan registered , the dose planning system of the Gamma Knife Model-B, was evaluated near tissue inhomogeneities, using the gel dosimetry method. The lack of electronic equilibrium around the small-diameter gamma beams can cause dose calculation errors in the neighborhood of an air-tissue interface. An experiment was designed to investigate the effects of inhomogeneity near the paranosal sinuses cavities. The homogeneous phantom was a spherical glass balloon of 16 cm diameter, filled with MAGIC gel; i.e., the normoxic polymer gel. Two hollow PVC balls of 2 cm radius, filled with N{sub 2} gas, represented the air cavities inside the inhomogeneous phantom. For dose calibration purposes, 100 ml gel-containing vials were irradiated at predefined doses, and then scanned in a MR unit. Linearity was observed between the delivered dose and the reciprocal of the T2 relaxation time constant of the gel. Dose distributions are the results of a single shot of irradiation, obtained by collimating all 201 cobalt sources to a known target in the phantom. Both phantoms were irradiated at the same dose level at the same coordinates. Stereotactic frames and fiducial markers were attached to the phantoms prior to MR scanning. The dose distribution predicted by the Gamma Knife planning system was compared with that of the gel dosimetry. As expected, for the homogeneous phantom the isodose diameters measured by the gel dosimetry and the GammaPlan registered differed by 5% at most. However, with the inhomogeneous phantom, the dose maps in the axial, coronal and sagittal planes were spatially different. The diameters of the 50% isodose curves differed 43% in the X axis and 32% in the Y axis for the Z=90 mm axial plane; by 44% in the X axis and 24% in the Z axis for the Y=90 mm coronal plane; and by 32% in the Z axis and 42% in the Y axis for the X=92 mm sagittal plane. The lack of ability of the GammaPlan registered to predict the rapid dose fall off, due

  8. Gamma Knife 3-D dose distribution near the area of tissue inhomogeneities by normoxic gel dosimetry.

    PubMed

    Isbakan, Fatih; Ulgen, Yekta; Bilge, Hatice; Ozen, Zeynep; Agus, Onur; Buyuksarac, Bora

    2007-05-01

    The accuracy of the Leksell GammaPlan, the dose planning system of the Gamma Knife Model-B, was evaluated near tissue inhomogeneities, using the gel dosimetry method. The lack of electronic equilibrium around the small-diameter gamma beams can cause dose calculation errors in the neighborhood of an air-tissue interface. An experiment was designed to investigate the effects of inhomogeneity near the paranosal sinuses cavities. The homogeneous phantom was a spherical glass balloon of 16 cm diameter, filled with MAGIC gel; i.e., the normoxic polymer gel. Two hollow PVC balls of 2 cm radius, filled with N2 gas, represented the air cavities inside the inhomogeneous phantom. For dose calibration purposes, 100 ml gel-containing vials were irradiated at predefined doses, and then scanned in a MR unit. Linearity was observed between the delivered dose and the reciprocal of the T2 relaxation time constant of the gel. Dose distributions are the results of a single shot of irradiation, obtained by collimating all 201 cobalt sources to a known target in the phantom. Both phantoms were irradiated at the same dose level at the same coordinates. Stereotactic frames and fiducial markers were attached to the phantoms prior to MR scanning. The dose distribution predicted by the Gamma Knife planning system was compared with that of the gel dosimetry. As expected, for the homogeneous phantom the isodose diameters measured by the gel dosimetry and the GammaPlan differed by 5% at most. However, with the inhomogeneous phantom, the dose maps in the axial, coronal and sagittal planes were spatially different. The diameters of the 50% isodose curves differed 43% in the X axis and 32% in the Y axis for the Z =90 mm axial plane; by 44% in the X axis and 24% in the Z axis for the Y=90 mm coronal plane; and by 32% in the Z axis and 42% in the Y axis for the X=92 mm sagittal plane. The lack of ability of the GammaPlan to predict the rapid dose fall off, due to the air cavities behind or near the

  9. First experience with a new negative pressure incision management system on surgical incisions after cardiac surgery in high risk patients

    PubMed Central

    2011-01-01

    Background Sternal wound infection remains a serious potential complication after cardiac surgery. A recent development for preventing wound complications after surgery is the adjunctive treatment of closed incisions with negative pressure wound therapy. Suggested mechanisms of preventive action are improving the local blood flow, removing fluids and components in these fluids, helping keep the incision edges together, protecting the wound from external contamination and promoting incision healing. This work reports on our initial evaluation and clinical experience with the Prevena™Incision Management System, a recently introduced new negative pressure wound therapy system specifically developed for treating closed surgical incisions and helping prevent potential complications. We evaluated the new treatment on sternal surgical incisions in patients with multiple co-morbidities and consequently a high risk for wound complications. Methods The Prevena™incision management system was used in 10 patients with a mean Fowler risk score of 15.1 [Range 8-30]. The negative pressure dressing was applied immediately after surgery and left in place for 5 days with a continuous application of -125 mmHg negative pressure. Wounds and surrounding skin were inspected immediately after removal of the Prevena™ incision management system and at day 30 after surgery. Results Wounds and surrounding skin showed complete wound healing with the absence of skin lesions due to the negative pressure after removal of the Prevena™ dressing. No device-related complications were observed. No wound complications occurred in this high risk group of patients until at least 30 days after surgery. Conclusions The Prevena™system appears to be safe, easy to use and may help achieve uncomplicated wound healing in patients at risk of developing wound complications after cardiothoracic surgery. PMID:22145641

  10. A randomised controlled trial of mini incision or conventional incision for saphenous vein harvesting in patients undergoing myocardial revascularization

    PubMed Central

    Gontijo de Deus, Kleber; Diogo Filho, Augusto; Cesar Santos, Paulo

    2016-01-01

    Objective Compare the evolution regarding the complications concerning two types of incision (conventional × mini-incision), for saphenectomy in patients that go under myocardial revascularization or otherwise known as coronary artery bypass surgery. Methods In January 2012 to August 2013, 66 patients were prospectively selected for coronary artery bypass with cardiopulmonary bypass surgery. These were divided into two groups: Conventional and Mini-Incision, with 33 patients in each group chosen in a random fashion and with knowledge of which technique to be used being presented only at the start of the surgery. In the conventional group, the patients received an incision to the lower member of 7–10 cm. The patients in the Mini-Incision group received an incision to the lower member of 3–4 cm, both performed without the use of any special material. Results The groups were similar in terms of clinical data and in the preoperative period. Males made up a greater part of the group with 63.7% and 81.9% in groups C and M, respectively. Among the complications analysed, edema (p = 0.011), hematoma (p = 0.020), dehiscence (p = 0.012) and infection (p = 0.012), were significantly greater in group C when compared to group M. When the matter comes to the variable in relation to the risk of Surgical Site Infections (SSI), no difference was found between the groups. Conclusion Coronary artery bypass surgery with mini-incision for saphenectomy, demonstrated a lower rate for preoperative complications when compared to saphenectomy under conventional incision procedures. PMID:27006766

  11. Fluvial incision into bedrock: Insights from morphometric analysis and numerical modeling of gorges incising glacial hanging valleys (Western Alps, France)

    NASA Astrophysics Data System (ADS)

    Valla, Pierre G.; van der Beek, Peter A.; Lague, Dimitri

    2010-06-01

    Bedrock gorges incising glacial hanging valleys potentially allow measurements of fluvial bedrock incision in mountainous relief. Using digital elevation models, topographic maps, and field reconnaissance, we identified and characterized 30 tributary hanging valleys incised by gorges near their confluence with trunk streams in the Romanche watershed, French Western Alps. Longitudinal profiles of these tributaries are all convex and have abrupt knickpoints at the upper limit of oversteepened gorge reaches. We reconstructed initial glacial profiles from glacially polished bedrock knobs surrounding the gorges in order to quantify the amount of fluvial incision and knickpoint retreat. From morphometric analyses, we find that mean channel gradients and widths, as well as knickpoint retreat rates, display a drainage area dependence modulated by bedrock lithology. However, there appears to be no relation between horizontal retreat and vertical downwearing of knickpoints. Assuming a postglacial origin of these gorges, our results imply high postglacial fluvial incision (0.5-15 mm yr-1) and knickpoint retreat (1-200 mm yr-1) rates that are, however, consistent with previous estimates. Numerical modeling was used to test the capacity of different fluvial incision models to predict the inferred evolution of the gorges. Results from simple end-member models suggest transport-limited behavior of the bedrock gorges. A more sophisticated model including dynamic width adjustment and sediment-dependent incision rates predicts present-day channel geometry only if a significant supply of sediment from the gorge sidewalls (˜10 mm yr-1) is triggered by gorge deepening, combined with pronounced inhibition of bedrock incision by sediment transport and deposition.

  12. Corrections to the knife-edge based reconstruction scheme of tightly focused light beams.

    PubMed

    Huber, C; Orlov, S; Banzer, P; Leuchs, G

    2013-10-21

    The knife-edge method is an established technique for profiling light beams. It was shown, that this technique even works for tightly focused beams, if the material and geometry of the probing knife-edges are chosen carefully. Furthermore, it was also reported recently that this method fails, when the knife-edges are made from pure materials. The artifacts introduced in the reconstructed beam shape and position depend strongly on the edge and input beam parameters, because the knife-edge is excited by the incoming beam. Here we show, that the actual beam shape and spot size of tightly focused beams can still be derived from knife-edge measurements for pure edge materials and different edge thicknesses by adapting the analysis method of the experimental data taking into account the interaction of the beam with the edge. PMID:24150349

  13. PRESAGE 3D dosimetry accurately measures Gamma Knife output factors

    NASA Astrophysics Data System (ADS)

    Klawikowski, Slade J.; Yang, James N.; Adamovics, John; Ibbott, Geoffrey S.

    2014-12-01

    Small-field output factor measurements are traditionally very difficult because of steep dose gradients, loss of lateral electronic equilibrium, and dose volume averaging in finitely sized detectors. Three-dimensional (3D) dosimetry is ideal for measuring small output factors and avoids many of these potential challenges of point and 2D detectors. PRESAGE 3D polymer dosimeters were used to measure the output factors for the 4 mm and 8 mm collimators of the Leksell Perfexion Gamma Knife radiosurgery treatment system. Discrepancies between the planned and measured distance between shot centers were also investigated. A Gamma Knife head frame was mounted onto an anthropomorphic head phantom. Special inserts were machined to hold 60 mm diameter, 70 mm tall cylindrical PRESAGE dosimeters. The phantom was irradiated with one 16 mm shot and either one 4 mm or one 8 mm shot, to a prescribed dose of either 3 Gy or 4 Gy to the 50% isodose line. The two shots were spaced between 30 mm and 60 mm apart and aligned along the central axis of the cylinder. The Presage dosimeters were measured using the DMOS-RPC optical CT scanning system. Five independent 4 mm output factor measurements fell within 2% of the manufacturer’s Monte Carlo simulation-derived nominal value, as did two independent 8 mm output factor measurements. The measured distances between shot centers varied by ±0.8 mm with respect to the planned shot displacements. On the basis of these results, we conclude that PRESAGE dosimetry is excellently suited to quantify the difficult-to-measure Gamma Knife output factors.

  14. Minimal incision posterior approach levator plication for aponeurotic ptosis

    PubMed Central

    Ng, D S; Chan, E; Ko, S T

    2015-01-01

    Purpose To assess the efficacy and predictability of a minimal incision posterior approach levator plication technique for correction of involutional ptosis. Method Retrospective chart review of patients with involutional aponeurotic ptosis underwent minimal incision posterior approach levator plication technique between August 2013 and June 2014 by a single surgeon. The upper lid was double everted, and the conjunctiva and Muller's muscle layers were incised vertically until the levator aponeurosis could be identified. The incision(s) was similar to performing incision and curettage of chalazion, except that the site was above the tarsal plate and extended towards the fornix. Then insertion of aponeurosis was dissected away from the anterior tarsal surface, and the more superiorly located levator was plicated on it with double arm suture(s). No tissue was excised in this procedure. Surgical success was defined as a postoperative margin reflex distance (MRD)>2 mm and<4.5 mm, interlid height<1 mm and satisfactory contour. Results Forty-four lids of 27 patients were included. Preoperative mean MRD was 0.48 +/− 0.56 mm. Severe ptosis of MRD<1 mm was present in 34/44 patients (77.3%). The postoperative mean MRD was 2.49 +/− 0.53 mm, and mean improvement was 2.02 +/− 0.61 mm, which was statistically significant (P<0.001). The overall success rate was 38/44 (86.4%). Conclusions Minimal incision posterior approach to levator plication was effective for the correction of aponeurotic ptosis with moderate to good levator function. PMID:25613849

  15. MCNP-based computational model for the Leksell Gamma Knife

    SciTech Connect

    Trnka, Jiri; Novotny, Josef Jr.; Kluson, Jaroslav

    2007-01-15

    We have focused on the usage of MCNP code for calculation of Gamma Knife radiation field parameters with a homogenous polystyrene phantom. We have investigated several parameters of the Leksell Gamma Knife radiation field and compared the results with other studies based on EGS4 and PENELOPE code as well as the Leksell Gamma Knife treatment planning system Leksell GammaPlan (LGP). The current model describes all 201 radiation beams together and simulates all the sources in the same time. Within each beam, it considers the technical construction of the source, the source holder, collimator system, the spherical phantom, and surrounding material. We have calculated output factors for various sizes of scoring volumes, relative dose distributions along basic planes including linear dose profiles, integral doses in various volumes, and differential dose volume histograms. All the parameters have been calculated for each collimator size and for the isocentric configuration of the phantom. We have found the calculated output factors to be in agreement with other authors' works except the case of 4 mm collimator size, where averaging over the scoring volume and statistical uncertainties strongly influences the calculated results. In general, all the results are dependent on the choice of the scoring volume. The calculated linear dose profiles and relative dose distributions also match independent studies and the Leksell GammaPlan, but care must be taken about the fluctuations within the plateau, which can influence the normalization, and accuracy in determining the isocenter position, which is important for comparing different dose profiles. The calculated differential dose volume histograms and integral doses have been compared with data provided by the Leksell GammaPlan. The dose volume histograms are in good agreement as well as integral doses calculated in small calculation matrix volumes. However, deviations in integral doses up to 50% can be observed for large

  16. MCNP-based computational model for the Leksell gamma knife.

    PubMed

    Trnka, Jiri; Novotny, Josef; Kluson, Jaroslav

    2007-01-01

    We have focused on the usage of MCNP code for calculation of Gamma Knife radiation field parameters with a homogenous polystyrene phantom. We have investigated several parameters of the Leksell Gamma Knife radiation field and compared the results with other studies based on EGS4 and PENELOPE code as well as the Leksell Gamma Knife treatment planning system Leksell GammaPlan (LGP). The current model describes all 201 radiation beams together and simulates all the sources in the same time. Within each beam, it considers the technical construction of the source, the source holder, collimator system, the spherical phantom, and surrounding material. We have calculated output factors for various sizes of scoring volumes, relative dose distributions along basic planes including linear dose profiles, integral doses in various volumes, and differential dose volume histograms. All the parameters have been calculated for each collimator size and for the isocentric configuration of the phantom. We have found the calculated output factors to be in agreement with other authors' works except the case of 4 mm collimator size, where averaging over the scoring volume and statistical uncertainties strongly influences the calculated results. In general, all the results are dependent on the choice of the scoring volume. The calculated linear dose profiles and relative dose distributions also match independent studies and the Leksell GammaPlan, but care must be taken about the fluctuations within the plateau, which can influence the normalization, and accuracy in determining the isocenter position, which is important for comparing different dose profiles. The calculated differential dose volume histograms and integral doses have been compared with data provided by the Leksell GammaPlan. The dose volume histograms are in good agreement as well as integral doses calculated in small calculation matrix volumes. However, deviations in integral doses up to 50% can be observed for large

  17. Gamma knife for obsessive compulsive disorder: can it be detrimental?

    PubMed

    Tripathi, Manjul; Mukherjee, Kanchan; Chhabra, Rajesh; Radotra, Ishan; Singh, Apinder P; Radotra, Bishan

    2014-01-01

    Functional neurological disorders (FND) have been a challenge to treat both for neurologists and neurosurgeons. Various ablative as well as non-ablative techniques have been used to treat these disorders. Gamma knife radiosurgery (GKRS) is also being practised to treat refractory obsessive- compulsive disorder (OCD). The subsequent complications of GKRS reported have been variable, with headache being the most common. We discuss here a rare complication of 'late onset radiation necrosis in bilateral caudate nuclei' in a patient after receiving GKRS three years back. This case highlights the need to be more cautious before administering ablative procedures in patients suffering with functional disorders. PMID:25050687

  18. Unusual clinical case: extraluminal manifestation of a tapeworm from the eviscerated midline incision in a post-surgery patient.

    PubMed

    Dural, Ahmet Cem; Celik, Muhammet Ferhat; Temizgonul, Baha; Unsal, Mustafa Gokhan; Akarsu, Cevher; Gonenc, Murat; Kalayci, Mustafa Uygar; Alis, Halil

    2015-04-01

    Taenia saginata infestation is one of the most common cestode infestations in humans, that may cause gastrointestinal tract related complications as a result of obstruction, perforation or anastomotic leakage. A 55-year-old male patient who was receiving palliative chemotherapy for stage IV gastric cancer was admitted to the emergency department for abdominal pain. A hollow viscus organ perforation was diagnosed and an emergency surgery was performed. On postoperative day 5, the patient's midline incision eviscerated and a moving taenia emerged, with abundant particulated fluid from the incision line. The patient was admitted for abdominal surgery due to suspected bowel perforation. During the abdominal exploration, a relaxed purse stitch of the feeding tube was observed and no other bowel perforations were seen. The patient underwent two planned surgery for abdominal cavity lavage after the removal of cestode. Unfortunately, the patient died sixteen days after his admission to the intensive care unit. This is the first case describing an extraluminal manifestation of a tapeworm in a midline incision from evisceration without intestinal perforation. PMID:25881535

  19. Lateral Erosion Encourages Vertical Incision in a Bimodal Alluvial River

    NASA Astrophysics Data System (ADS)

    Gran, K. B.

    2015-12-01

    Sand can have a strong impact on gravel transport, increasing gravel transport rates by orders of magnitude as sand content increases. Recent experimental work by others indicates that adding sand to an armored bed can even cause armor to break-up and mobilize. These two elements together help explain observations from a bimodal sand and gravel-bedded river, where lateral migration into sand-rich alluvium breaks up the armor layer, encouraging further incision into the bed. Detailed bedload measurements were coupled with surface and subsurface grain size analyses and cross-sectional surveys in a seasonally-incised channel carved into the upper alluvial fan of the Pasig-Potrero River at Mount Pinatubo, Philippines. Pinatubo erupted in 1991, filling valleys draining the flanks of the volcano with primarily sand-sized pyroclastic flow debris. Twenty years after the eruption, sand-rich sediment inputs are strongly seasonal, with most sediment input to the channel during the rainy season. During the dry season, flow condenses from a wide braided planform to a single-thread channel in most of the upper basin, extending several km onto the alluvial fan. This change in planform creates similar unit discharge ranges in summer and winter. Lower sediment loads in the dry season drive vertical incision until the bed is sufficiently armored. Incision proceeds downstream in a wave, with increasing sediment transport rates and decreasing grain size with distance downstream, eventually reaching a gravel-sand transition and return to a braided planform. Incision depths in the gravel-bedded section exceeded 3 meters in parts of a 4 km-long study reach, a depth too great to be explained by predictions from simple winnowing during incision. Instead, lateral migration into sand-rich alluvium provides sufficient fine sediment to break up the armor surface, allowing incision to start anew and increasing the total depth of the seasonally-incised valley. Lateral migration is recorded in a

  20. Episodic incision of the Colorado River in Glen Canyon, Utah

    USGS Publications Warehouse

    Garvin, C.D.; Hanks, T.C.; Finkel, R.C.; Heimsath, A.M.

    2005-01-01

    Incision rates of the Colorado River are integral to understanding the development of the Colorado Plateau. Here we calculate episodic incision rates of the Colorado River based on absolute ages of two levels of Quaternary deposits adjacent to Glen Canyon, Utah, along the north flank of Navajo Mountain. Minimum surface ages are determined by a combination of cosmogenic radionuclide surface exposure ages, uranium series and soil-development formation times. Bedrock incision rates of the Colorado River between c. 500 ka and c. 250 ka, and c. 250 ka to present are c. 0??4 m ka-1 and c. 0??7 m ka-1, respectively. These rates are more than double the rates reported in the Grand Canyon, suggesting that the Colorado River above Lees Ferry is out of equilibrium with the lower section of the river. We also determine incision rates of two tributaries to the Colorado River. Oak Creek and Bridge Creek flow off Navajo Mountain into Glen Canyon from the southeast. Oak Creek and Bridge Creek both have incision rates of c. 0??6 m ka-1 over the past c. 100 ka at points about 9 km away from the main stem of the Colorado River. Copyright ?? 2005 John Wiley & Sons, Ltd.

  1. H incision--method of choice for radical neck dissection.

    PubMed

    Kambic, V; Sĭrca, A

    1977-05-01

    To prevent skin necrosis, fistula formation and rupture of the carotid arteries after RND, vascularization of the skin of the neck has been considered. The neck vessels (in cadavers) were injected with coloured media and specimens of the skin were cleared (Spalteholz method). The arteries supplying the skin of the neck followed in general an obviously longitudinal course: one group of cutaneous arteries descending from the branches of the external carotid; another group ascending from the branches of the subclavian artery. The upper and lower groups of arteries joined approximately in the middle of the neck. The density of cutaneous arteries in the neck was much poorer than in the facial skin. On the basis of these anatomic data, an incision for RND has been proposed in the form of an H or three-quarter H, in which the transverse line of the incision follows the least vascularized skin region of the neck, without interrupting the great skin vessels. Incisions in the form of a Z or a double Y, OR McFee's incision, do not fulfil this requirement. The authors also report the results of wound healing after RND in 184 patients who were operated in the period fron 1968 to 1975 at the E. N. T. clinic of Ljubljana, where the H incision or one of its modifications was used. PMID:864314

  2. TEACHING NEUROMUSCULAR RELAXATION.

    ERIC Educational Resources Information Center

    NORRIS, JEANNE E.; STEINHAUS, ARTHUR H.

    THIS STUDY ATTEMPTED TO FIND OUT WHETHER (1) THE METHODS FOR ATTAINING NEUROMUSCULAR RELAXATION THAT HAVE PROVED FRUITFUL IN THE ONE-TO-ONE RELATIONSHIP OF THE CLINIC CAN BE SUCCESSFULLY ADAPTED TO THE TEACHER-CLASS RELATIONSHIP OF THE CLASSROOM AND GYMNASIUM, AND (2) NEUROMUSCULAR RELAXATION CAN BE TAUGHT SUCCESSFULLY BY AN APPROPRIATELY TRAINED…

  3. Mechanism of rotational relaxation.

    NASA Technical Reports Server (NTRS)

    Polanyi, J. C.; Woodall, K. B.

    1972-01-01

    A model is presented which describes the characteristic pattern of relaxation of a nonthermal rotational distribution of hydrogen halide, peaked initially at high rotational quantum number J, to a thermal distribution without generating a peak at intermediate J. A method for correcting infrared chemiluminiscence data for modest rotational relaxation is also suggested.

  4. Dosimetrical evaluation of Leksell Gamma Knife 4C radiosurgery unit

    NASA Astrophysics Data System (ADS)

    Sajeev, Thomas; Mustafa, Mohamed M.; Supe, Sanjay S.

    2011-01-01

    A number of experiments was performed using standard protocols, in order to evaluate the dosimetric accuracy of Leksell Gamma Knife 4C unit. Verification of the beam alignment has been performed for all collimators using solid plastic head phantom and Gafchromic™ type MD-55 films. The study showed a good agreement of Leksell Gammaplan calculated dose profiles with experimentally determined profiles in all three axes. Isocentric accuracy is verified using a specially machined cylindrical aluminium film holder tool made with very narrow geometric tolerances aligned between trunnions of 4 mm collimator. Considering all uncertainties in all three dimensions, the estimated accuracy of the unit was 0.1 mm. Dose rate at the centre point of the unit has been determined according to the IAEA, TRS-398 protocol, using Unidose-E (PTW-Freiburg, Germany) with a 0.125 cc ion chamber, over a period of 6 years. The study showed that the Leksell Gamma Knife 4C unit is excellent radiosurgical equipment with high accuracy and precision, which makes it possible to deliver larger doses of radiation, within the limits defined by national and international guidelines, applicable for stereotactic radiosurgery procedures.

  5. Endoscopic treatment for pancreatic diseases: Needle-knife-guided cannulation via the minor papilla

    PubMed Central

    Wang, Wei; Gong, Biao; Jiang, Wei-Song; Liu, Lei; Bielike, Kouken; Xv, Bin; Wu, Yun-Lin

    2015-01-01

    AIM: To determine the efficacy and safety of meticulous cannulation by needle-knife. METHODS: Three needle-knife procedures were used to facilitate cannulation in cases when standard cannulation techniques failed. A total of 104 cannulations via the minor papilla attempted in 74 patients at our center between January 2008 and June 2014 were retrospectively reviewed. RESULTS: Standard methods were successful in 79 cannulations. Of the 25 cannulations that could not be performed by standard methods, 19 were performed by needle-knife, while 17 (89.5%) were successful. Needle-knife use improved the success rate of cannulation [76.0%, 79/104 vs 92.3%, (79 + 17)/104; P = 0.001]. When the 6 cases not appropriate for needle-knife cannulation were excluded, the success rate was improved further (80.6%, 79/98 vs 98.0%, 96/98; P = 0.000). There were no significant differences in the rates of post-endoscopic retrograde cholangiopancreatography adverse events between the group using standard methods alone and the group using needle-knife after failure of standard methods (4.7% vs 10.5%, P = 0.301). CONCLUSION: The needle-knife procedure may be an alternative method for improving the success rate of cannulation via the minor papilla, particularly when standard cannulation has failed. PMID:26019460

  6. The problem of insufficient incisal display: a case presentation.

    PubMed

    Castillo, Rodrigo

    2010-01-01

    Enhancement of facial beauty is one of the primary elective goals of patients seeking dental care. Frequently, improvements in natural beauty can be expected to follow restoration of ideal relationships between the denture and the facial soft tissues. A very important feature in a youthful appearance is the incisal tooth display; the amount of maxillary incisal exposure gradually decreases with age, accompanied by a gradual increase in mandibular incisal exposure. However, this problem could be present in young people where the effects of age should not be apparent yet. There are some other factors that could accelerate this process. The present case illustrates the improvement and rejuvenation of an unesthetic young smile through restorative treatment. PMID:20589259

  7. Management of insertional Achilles tendinopathy through a Cincinnati incision

    PubMed Central

    Carmont, Michael R; Maffulli, Nicola

    2007-01-01

    Background About 10% of patients not responding to 3–6 months of conservative management for insertional Achilles tendinopathy undergo surgery. Traditionally, surgery of the Achilles tendon is performed through longitudinal extensile incisions. Such surgery is prone to the complications of wound healing, wound breakdown and iatrogenic nerve injury. Methods We describe our current method of exposure of the Achilles tendon insertion and debridement of the peritendinous and tendon tissue with osteotomy of the calcaneum through a transverse skin incision at the level of the Achilles insertion. Results This method has been used since 2002 on over 40 patients for exposure of the Achilles tendon insertion and the distal Achilles tendon. Conclusion The Cincinnati incision allows adequate exposure, has minimal risk of symptomatic iatrogenic nerve injury, and has minimal problems related to the scar. PMID:17697370

  8. Force modeling for incision surgery into tissue with haptic application

    NASA Astrophysics Data System (ADS)

    Kim, Pyunghwa; Kim, Soomin; Choi, Seung-Hyun; Oh, Jong-Seok; Choi, Seung-Bok

    2015-04-01

    This paper presents a novel force modeling for an incision surgery into tissue and its haptic application for a surgeon. During the robot-assisted incision surgery, it is highly urgent to develop the haptic system for realizing sense of touch in the surgical area because surgeons cannot sense sensations. To achieve this goal, the force modeling related to reaction force of biological tissue is proposed in the perspective on energy. The force model describes reaction force focused on the elastic feature of tissue during the incision surgery. Furthermore, the force is realized using calculated information from the model by haptic device using magnetorheological fluid (MRF). The performance of realized force that is controlled by PID controller with open loop control is evaluated.

  9. [Dorso-ventral continuous irrigation using the Incise Pouch].

    PubMed

    Dittrich, K; Kriwanek, S; Armbruster, C

    1993-01-01

    Dorso-ventral lavage procedures in the treatment of abdominal sepsis are often complicated by technical and nursing problems. With the help of the Incise Pouch, which consists of an adhesive foil with a plastic bag around it, we have succeeded in solving the main problems of the dorso-ventral lavage procedure. (1) All the lavage solution is collected in the bag and drawn into a vacuum pump. The suction drains are placed directly in the bag. This enables us to measure the lavage solution exactly. (2) There is no leakage of liquid into the bed, so that the patient remains dry. (3) The danger of intestinal fistulas or intraabdominal bleeding caused by suction drains is eliminated (by putting them into the bag of the Incise Pouch). If reexploration of the abdominal cavity ("on demand" or planned) is done, the Incise Pouch remains in position. This method makes early diagnosis and treatment of postoperative complications possible. PMID:8326812

  10. Very long-term incision dynamics of big rivers

    NASA Astrophysics Data System (ADS)

    Grimaud, Jean-Louis; Chardon, Dominique; Beauvais, Anicet

    2014-11-01

    Constraining large-scale incision dynamics of shield and post-rift margin domains is key to understanding the sediment routing system over the overwhelming part of the continental surface. Based on dated and regionally correlated incision markers from West Africa, we reconstruct for the first time the entire paleo-long profiles of big rivers such as the Niger at ca. 24, 11 and 6 Ma, as well as the Eocene topography those rivers have dissected. The results provide boundary conditions and calibration for surface process models and paleodrainage dynamics. Though spatially and temporally variable, incision remained mostly below 10 m/my with a mean around 5 m/my. The spatial stability of both the river outlets and divides imposed maintenance or increasing concavity of the river long profiles through time, resulting from spatially contrasted adjustment of river segments bounded by recurrent lithogenic knickzones that persisted since 24 Ma. Drainages evolved preferentially by very slow slope decrease or uniform incision in between the stationary knickzones of evolving amplitude, with apparently no relation to base level change. Therefore, knickzone height or position may not simply reflect the transient response of big rivers to base level fall as predicted by stream-power incision river models. This may also challenge uplift histories of deep continental interiors retrieved from river long profiles inversion relying on such models. Very slow incision allowed amplification of the Hoggar hot spot swell and flexural uplift of the continental margin to be recorded by river long profiles, emphasizing the potential of big non-orogenic rivers as gauges of dynamic topography.

  11. [Evolution and Development Trend of Lung Cancer Surgical Incision].

    PubMed

    Xie, Dong; Chen, Chang; Jiang, Gening

    2016-06-20

    Minimally invasive, safe and tumor-free are the main principles of the choice of surgical incision in lung cancer surgery. In recent years, with the advances in minimally invasive techniques, single-port video assisted thoracic surgery (VATS), robot-assisted thoracoscopic (RATS), suboxiphoid single-port VATS, simultaneous bilateral VATS pulmonary resection, are emerging approaches, single-port VATS has become one of the most exciting new developments in minimally invasive thoracic surgery in recent years. This paper reviews the evolution and trends of surgical incision in lung cancer surgery. PMID:27335293

  12. A new glove port for single incision procedure

    PubMed Central

    Ko, Yoon Song; Yoon, Sam Youl; Han, Hyung Joon; Yim, Tae Wan

    2015-01-01

    Single-incision laparoscopic surgery has gained increasing attention due to its potential to improve the benefits of laparoscopic surgery. However, inconvenience remains for inexperienced surgeons during surgery when instruments conflict with each other, and a glove port is used hesitantly for such diagnosis related groups (DRG) because of its high cost. Authors made a new glove port by an odd surgical gloves and one wound protectors. This glove port is ease to make besides being convenient to us, and inexpensive. This new glove port has the benefit of easy utilization and cost effectiveness for surgeons performing single-incision laparoscopic surgery. PMID:26576410

  13. Development of knife-edge field emission cathodes on (110) silicon wafers

    NASA Astrophysics Data System (ADS)

    Lee, Bo; Barasch, E. F.; Mazumdar, T.; McIntyre, P. M.; Pang, Y.; Trost, H.-J.

    1993-04-01

    Knife-edge field emission cathodes have been fabricated on (110) silicon wafers. The emitter structure consists of an array of razor shaped silicon knife edges standing up on silicon substrates. The radii of the sharp edges seen with SEM are less than 250 Å; the height of the knife edges is 5 to 8 μm; and the gate-emitter spacing is ˜0.1 μm. Because of the very small gate-emitter spacing and the large height/width ratio of the emitter, the structure resembles an optimized emitter geometry concluded from our study. The fabrication process and results are presented.

  14. Application of a cervical low incision in the functional neck dissection of thyroid papillary carcinoma

    PubMed Central

    XU, JIAJIE; CHEN, CHAO; ZHENG, CHUANMING; WANG, KEJING; SHANG, JINBIAO; FANG, XIANHUA; GE, MINGHUA; TAN, ZHUO

    2016-01-01

    The present study aimed to discuss the advantage of the application of a cervical low incision for functional neck dissection in patients with thyroid papillary carcinoma. The study was a retrospective analysis of 87 thyroid papillary carcinoma patients; cervical low incision in the functional neck dissection was applied for 47 cases and the classic ‘L’ incision was applied for 40 cases. The different integrity, surgical time, blood loss and the aesthetic property of the incision were compared between the cervical low incision and the classic ‘L’ incision for lateral neck dissection of thyroid cancer. The postoperative pathological diagnosis was that the average total amount and the region II lymph nodes of the unilateral neck dissection were 33 and 10 for the cervical low incision group, and 32 and 11 for the classic ‘L’ incision group, respectively (P>0.05). The average unilateral neck dissection times were 87 and 58 min for the cervical low incision group and the classic ‘L’ incision group, respectively (P<0.05). The blood loss of the cervical low incision group was 67 ml, while the loss for the classic ‘L’ incision group was 61 ml (P>0.05). The postoperative incision of the cervical low incision group was smaller and more concealing. Additionally, the cosmetic deformities were milder for an inconspicuous cervical scar, and the sensation was improved for the patients in comparison with the classic ‘L’ incision group. These results suggest that the application of cervical low incision for functional neck dissection in thyroid papillary carcinoma patients aids in reducing postoperative complications, without increasing recurrence rates. Therefore, the classic ‘L’ incision can be replaced by the cervical low incision. PMID:27073645

  15. Imaging and investigating the effects of incision angle of clear corneal cataract surgery with optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Rao, Bin; Zhang, Jun; Taban, Mehran; McDonnell, Peter J.; Chen, Zhongping

    2003-12-01

    Effects of incision angle in construction of clear corneal cataract incision are studied with optical coherence tomography (OCT). A stable incision angle range is found to be existent for single-planed, clear corneal cataract incisions. When well pressurized, incision angles within this stable range result in well-apposed incision edges that resist gapping while incision angles falling outside this range have a larger tendency for wound leakage. It is also shown that a two-planed incision can effectively expand the stable range. For incision angles outside the stable range, the farther the incision angle is away from stable range, the larger the gap between incision wound edges when well pressurized. These findings emphasize the significance of incision construction to the self-sealing property of clear corneal cataract incisions. Finally, we demonstrate that OCT could be an effective modality for imaging and monitoring corneal surgery.

  16. INVESTIGATION OF WASTE GLASS POURING PROCESS OVER A KNIFE EDGE

    SciTech Connect

    M.A. Ebadian, Ph.D.

    1999-01-01

    Vitrification is the process of capturing radioactive waste in glass. The Savannah River Site's (SRS) Defense Waste Processing Facility (DWPF) is one of the facilities using the vitrification technology to treat and immobilize radioactive waste. The objective of the project is to investigate the pouring behavior of molten glass over a pour spout knife edge. Experiments are run using simulant glass containing the same chemical formulation as the radioactive sludge glass, but without radioactive contaminants. The purpose of these tests is to obtain actual glass data that, when combined with previous cold data from other fluids, will provide an overall understanding of the physics of liquids flowing over a pour spout and knife edge, A specific objective is to verify computational fluid dynamics (CFD) models with a range of liquid data with particular emphasis on glass so as to provide confidence in use of these CFD models for designing a new improved pour spout for the DWPF melter. The work to be performed at FIU-HCET includes assembling the melting and pouring system that mimics the DWPF melter and determining the key parameters that may influence wicking. Information from the FIU-HCET melter tests will lead to better operating guidelines for the DWPF melter so as to avoid wicking. During FY98, a bench-scale melter complete with pour spout and a knife edge was designed and assembled at FIU-HCET. Initially, the system was tested with glycerine. Subsequently, glass provided by SRS was used for experimentation. Flow visualization tests were performed with the melter in FY98 to investigate the pouring behavior of molten glass over a pour spout model simulating a DWPF pour spout of the original design. Simulant glass containing the same chemical formulation as sludge glass but without radioactive contaminants was used in the tests. All the tasks and milestones mentioned in the PTP for the project were accomplished. The project completed its second year, and this document

  17. Stereotactic radiosurgery using the gamma knife for acoustic neuromas

    SciTech Connect

    Foote, R.L.; Coffey, R.J.; Swanson, J.W.

    1995-07-15

    The purpose of this investigation was to assess the efficacy and toxicity of stereotactic radiosurgery using the gamma knife for acoustic neuromas. Between January 1990 and January 1993, 36 patients with acoustic neuromas were treated with stereotactic radiosurgery using the gamma knife. The median maximum tumor diameter was 21 mm (range: 6-32 mm). Tumor volumes encompasses within the prescribed isodose line varied from 266 to 8,667 mm{sup 3} (median: 3,135 mm{sup 3}). Tumors {<=} 20 mm in maximum diameter received a dose of 20 Gy to the margin, tumors between 21 and 30 mm received 18 Gy, and tumors > 30 mm received 16 Gy. The dose was prescribed to the 50% isodose line in 31 patients and to the 45%, 55%, 60%, 70%, and 80% isodose line in one patient each. Nine tumors (26%) were smaller, and 26 tumors (74%) were unchanged. No tumor had progressed. The 1- and 2-year actuarial incidences of facial neuropathy were 52.2% and 66.5%, respectively. The 1- and 2-year actuarial incidences of trigeminal neuropathy were 33.7% and 58.9%, respectively. The 1- and 2-year actuarial incidence of facial or trigeminal neuropathy (or both) was 60.8% and 81.7%, respectively. Multivariate analysis revealed that the following were associated with the time of onset or worsening of facial weakness or trigeminal neuropathy: (a) patients < age 65 years, (b) dose to the tumor margin, (c) maximum tumor diameter {>=} 21 mm, (d) use of the 18 mm collimator, and (e) use of > five isocenters. The 1- and 2-year actuarial rates of preservation of useful hearing (Gardner-Robertson class I or II) were 100% and 41.7% {plus_minus} 17.3, respectively. Stereotactic radiosurgery using the gamma knife provides short-term control of acoustic neuromas when a dose of 16 to 20 Gy to the tumor margin is used. Preservation of useful hearing can be accomplished in a significant proportion of patients. 30 refs., 5 tabs.

  18. Single-incision pediatric endosurgery in newborns and infants

    PubMed Central

    Kozlov, Yury; Novozhilov, Vladimir; Baradieva, Polina; Krasnov, Pavel; Kovalkov, Konstantin; Muensterer, Oliver J

    2015-01-01

    This study focuses on the successful application of single-incision pediatric endosurgery in the treatment of congenital anomalies and acquired diseases in neonates and infants. The purpose of this scientific review consists in highlighting the spectrum, indications, applicability, and effectiveness of single-port endosurgery in children during the first 3 postnatal months. PMID:26566478

  19. Learning micro incision surgery without the learning curve

    PubMed Central

    Navin, Shoba; Parikh, Rajul

    2008-01-01

    We describe a method of learning micro incision cataract surgery painlessly with the minimum of learning curves. A large-bore or standard anterior chamber maintainer (ACM) facilitates learning without change of machine or preferred surgical technique. Experience with the use of an ACM during phacoemulsification is desirable. PMID:18292624

  20. Single-incision laparoscopic surgery for biliary tract disease

    PubMed Central

    Chuang, Shu-Hung; Lin, Chih-Sheng

    2016-01-01

    Single-incision laparoscopic surgery (SILS), or laparoendoscopic single-site surgery, has been employed in various fields to minimize traumatic effects over the last two decades. Single-incision laparoscopic cholecystectomy (SILC) has been the most frequently studied SILS to date. Hundreds of studies on SILC have failed to present conclusive results. Most randomized controlled trials (RCTs) have been small in scale and have been conducted under ideal operative conditions. The role of SILC in complicated scenarios remains uncertain. As common bile duct exploration (CBDE) methods have been used for more than one hundred years, laparoscopic CBDE (LCBDE) has emerged as an effective, demanding, and infrequent technique employed during the laparoscopic era. Likewise, laparoscopic biliary-enteric anastomosis is difficult to carry out, with only a few studies have been published on the approach. The application of SILS to CBDE and biliary-enteric anastomosis is extremely rare, and such innovative procedures are only carried out by a number of specialized groups across the globe. Herein we present a thorough and detailed analysis of SILC in terms of operative techniques, training and learning curves, safety and efficacy levels, recovery trends, and costs by reviewing RCTs conducted over the past three years and two recently updated meta-analyses. All existing literature on single-incision LCBDE and single-incision laparoscopic hepaticojejunostomy has been reviewed to describe these two demanding techniques. PMID:26811621

  1. Phenomenon of mucous retention in the incisive canal.

    PubMed

    Keith, D A

    1979-11-01

    Mucous glands are rarely found in the anterior palate but may be observed in the incisive canal. A case history is presented of a lesion that resembled a nasopalatine cyst both clinically and radiographically but which was in fact an intra-bony extravasation phenomenon. PMID:290778

  2. Cosmetic selection of skin incision for resection of choledochal cyst in young female patients

    PubMed Central

    Choi, Jong-Woo; Ha, Tae-Yong; Song, Gi-Won; Jung, Dong-Hwan

    2016-01-01

    Backgrounds/Aims Open surgery for choledochal cyst has a disadvantage of skin incision scar from operative wound, which can be a definite disadvantage especially in young female patients. This study focused on the cosmetic aspect of skin incision for resection of choledochal cyst in young female patients. Methods During a 2-year study period, 11 adult female patients aged less than 40 years underwent primary resection of choledochal cyst by a single surgeon. The cosmetic effect of two types of skin incision was evaluated. Results The patients underwent mini-laparotomy through either a right subcostal incision (n=8) or an upper midline incision (n=3). The mean length of skin incision was 10 cm for right subcostal incisions and 9 cm for upper midline incisions. It took approximately 1 hour to repair the operative wound meticulously in both groups. At the 6 month to 1 year follow-up, a slight bulge on the skin scar was observed in 3 (37.5%) patients of the right subcostal incision group and 1 (33.3%) patient of the upper midline incision group. Conclusions The results of this preliminary study support the claim that cosmetic effect of the upper midline incision for CCD surgery appears to be non-inferior to that of the right subcostal incision if the incision is placed accurately and repaired very meticulously. PMID:27621750

  3. Z skin incision in reduced-port surgery for colorectal cancer

    PubMed Central

    FUJINO, SHIKI; MIYOSHI, NORIKATSU; OHUE, MASAYUKI; NOURA, SHINGO; FUJIWARA, YOSHIYUKI; HIGASHIYAMA, MASAHIKO; YANO, MASAHIKO

    2016-01-01

    Laparoscopic surgery for colorectal cancer (CRC) has recently gained in popularity due to the fewer trocars and shorter incision, leading to reduced wound pain and improved cosmetic outcome. In July, 2013, reduced-port surgery (RPS) was introduced and has been performed thereafter in our hospital. An umbilical incision is used for a main port in RPS, through which the specimen is removed and the anastomosis is performed. In order to make the incision shorter, we introduced the Z skin incision in RPS. In this study, we aimed to discuss this method and evaluate the short-term outcome. Among CRC patients undergoing RPS, Z skin incision (n=14) was compared to conventional skin incision (n=15). The clinical and surgical factors were evaluated and there were no significant differences in terms of gender, age, body mass index, tumor site, procedure, operative time, blood loss or complications between the two groups. The median incision length at the umbilicus was significantly shorter in the Z incision group (P=0.004). Particularly in functional end-to-end anastomosis, the median incision length was 2.5 cm in the Z skin incision group and 4.0 cm in the conventional incision group (P=0.018). In conclusion, Z skin incision is a useful technique for achieving an effective length of skin incision in RPS for CRC. PMID:27073675

  4. Late Quaternary rates of stream incision in Northeast Peloponnese, Greece

    NASA Astrophysics Data System (ADS)

    Karymbalis, Efthimios; Papanastassiou, Dimitrios; Gaki-Papanastassiou, Kalliopi; Ferentinou, Maria; Chalkias, Christos

    2016-05-01

    This study focuses on defining rates of fluvial incision for the last 580±5 kyr along valley systems of eight streams that drain the eastern part of the northern Peloponnese. The streams are developed on the uplifted block of the offshore-running Xylokastro normal fault, one of the main faults bounding the southern edge of the Gulf of Corinth half-graben, and have incised a set of ten uplifted marine terraces having an amphitheatric shape. These terraces range in age from 60±5 kyr to 580±5 kyr and have been mapped in detail and correlated with late Pleistocene oxygen-isotope stages of high sea-level stands by previous studies. The terraces were used in this paper as reference surfaces in order to define fluvial incision rates at the lower reaches of the studied streams. To evaluate incision rates, thirty-three topographic valley cross-sections were drawn using fieldwork measurements as well as using a highly accurate (2×2 cell size) Digital Elevation Model (DEM) at specific locations where streams cut down the inner edges of the marine terraces. For each cross-section the ratio of valley floor width to valley height (Vf) and long-term mean stream incision rates were estimated for the last 580±5 kyr, while rock uplift rates were estimated for the last 330±5 kyr. The geomorphic evolution of the valleys on the uplifted block of the Xylokastro fault has been mainly driven by the lithology of the bedrock, sea level fluctuations during the late Quaternary, and incision of the channels due to the tectonic uplift. Stream incision rates range from 0.10±0.1 mm/yr for the last 123±7 kyr to 1.14±0.1 mm/yr for the last 310±5 kyr and are gradually greater from east to west depending on the distance from the trace of the fault. Downcutting rates are comparable with the rock uplift rates, which range from 0.4±0.02 mm/yr to 1.49±0.12 mm/yr, over the last 330±5 kyr.

  5. Late Quaternary rates of stream incision in Northeast Peloponnese, Greece

    NASA Astrophysics Data System (ADS)

    Karymbalis, Efthimios; Papanastassiou, Dimitrios; Gaki-Papanastassiou, Kalliopi; Ferentinou, Maria; Chalkias, Christos

    2016-09-01

    This study focuses on defining rates of fluvial incision for the last 580±5 kyr along valley systems of eight streams that drain the eastern part of the northern Peloponnese. The streams are developed on the uplifted block of the offshore-running Xylokastro normal fault, one of the main faults bounding the southern edge of the Gulf of Corinth half-graben, and have incised a set of ten uplifted marine terraces having an amphitheatric shape. These terraces range in age from 60±5 kyr to 580±5 kyr and have been mapped in detail and correlated with late Pleistocene oxygen-isotope stages of high sea-level stands by previous studies. The terraces were used in this paper as reference surfaces in order to define fluvial incision rates at the lower reaches of the studied streams. To evaluate incision rates, thirty-three topographic valley cross-sections were drawn using fieldwork measurements as well as using a highly accurate (2×2 cell size) Digital Elevation Model (DEM) at specific locations where streams cut down the inner edges of the marine terraces. For each cross-section the ratio of valley floor width to valley height (Vf) and long-term mean stream incision rates were estimated for the last 580±5 kyr, while rock uplift rates were estimated for the last 330±5 kyr. The geomorphic evolution of the valleys on the uplifted block of the Xylokastro fault has been mainly driven by the lithology of the bedrock, sea level fluctuations during the late Quaternary, and incision of the channels due to the tectonic uplift. Stream incision rates range from 0.10±0.1 mm/yr for the last 123±7 kyr to 1.14±0.1 mm/yr for the last 310±5 kyr and are gradually greater from east to west depending on the distance from the trace of the fault. Downcutting rates are comparable with the rock uplift rates, which range from 0.4±0.02 mm/yr to 1.49±0.12 mm/yr, over the last 330±5 kyr.

  6. A modular Geant4 model of Leksell Gamma Knife Perfexion™

    NASA Astrophysics Data System (ADS)

    Pipek, J.; Novotný, J.; Novotný, J., Jr.; Kozubíková, P.

    2014-12-01

    This work presents a Monte Carlo model of Leksell Gamma Knife Perfexion as well as the main parameters of the dose distribution in the standard phantom obtained using this model. The model is developed in the Geant4 simulation toolkit in a modular way which enables its reuse in other Perfexion studies. Large phase space files were created, containing particles that are entering the inner machine cavity after being transported through the collimation system. All 14 output factors of the machine and effective output factors for both the 4 mm (0.830 ± 0.009) and 8 mm (0.921 ± 0.004) collimators were calculated. Dose profiles along the main axes are also included for each collimator size. All results are compared to the values obtained from the treatment planning system, from experiments, and from other Monte Carlo models.

  7. A modular Geant4 model of Leksell Gamma Knife Perfexion™.

    PubMed

    Pipek, J; Novotný, J; Novotný, J; Kozubíková, P

    2014-12-21

    This work presents a Monte Carlo model of Leksell Gamma Knife Perfexion as well as the main parameters of the dose distribution in the standard phantom obtained using this model. The model is developed in the Geant4 simulation toolkit in a modular way which enables its reuse in other Perfexion studies. Large phase space files were created, containing particles that are entering the inner machine cavity after being transported through the collimation system. All 14 output factors of the machine and effective output factors for both the 4 mm (0.830 ± 0.009) and 8 mm (0.921 ± 0.004) collimators were calculated. Dose profiles along the main axes are also included for each collimator size. All results are compared to the values obtained from the treatment planning system, from experiments, and from other Monte Carlo models. PMID:25415510

  8. Gamma knife radiosurgery for medically refractory idiopathic trigeminal neuralgia.

    PubMed

    Kang, J H; Yoon, Y S; Kang, D W; Chung, S S; Chang, J W

    2008-01-01

    Gamma knife radiosurgery (GKS) has been generally considered as a viable therapeutic option for the management of medically refractory idiopathic trigeminal neuralgia (TN). We reviewed our experience with GKS in patients with TN. Between Feb 1996 and May 2006, 77 patients with medical refractory idiopathic TN were treated using GKS. Thirty-six patients who had undergone other previous procedures, previous GKS, or had brain stem lesion, atypical symptoms, were excluded from this study. Pain improvement was achieved in 38 of the patients with TN (pain response rate 92.7%). Twenty-three patients were pain free and 15 had reduced pain. There were no serious complications. We think that GKS is an effective treatment option for patients with medical refractory idiopathic TN. PMID:18642631

  9. In-line digital holography with double knife edge

    NASA Astrophysics Data System (ADS)

    Ramirez, Claudio; Iemmi, Claudio; Campos, Juan

    2015-06-01

    We study and test a new technique for in-line digital holography which avoids the formation of the conjugate images. Inline digital holography is based in a common path configuration. In this case, the hologram is produced by the interference between the reference wave front and the diffracted wave front by an almost transparent object. Twin images are obtained with obscured rings that difficult the determination of the best focusing plane. To avoid the conjugated image, the information of the magnitude and phase of the wave front are needed. In a recent work a new in-line digital holography technique was proposed. In this method the object is illuminated with a collimated wave front. A plane, close to the particles distribution is imaged onto a CCD by means of a convergent lens and at the same time, a knife edge is placed in the focal plane of the lens in order to block half of spatial frequency spectrum. In this way, by means of a numerical processing performed on the Fourier plane, it is possible to eliminate one of the components (real or conjugate) of the reconstructed images nevertheless it is observed a tiny deformation of the resulting hologram image. To compensate this effect, we propose a new configuration in which we implement the knife edge technique on both parts of the spectrum at the same time. Finally in the computer, we process the holograms to build one complete without deformation. This hologram is used to recover the wave front at different planes without the influence of the conjugate image.

  10. Thoracoscopic surgery via a single-incision subxiphoid approach is associated with less postoperative pain than single-incision transthoracic or three-incision transthoracic approaches for spontaneous pneumothorax

    PubMed Central

    Wang, Bing-Yen; Chang, Yin-Chun; Chang, Yih-Chen; Wang, Kung-Min; Lin, Ching-Hsiung; Lin, Sheng-Hao

    2016-01-01

    Background Comparison of the degree of postoperative pain associated with different thoracoscopic surgical techniques for spontaneous pneumothorax has never reported. In this study we compared perioperative outcomes and degrees of postoperative pain associated with single-incision subxiphoid thoracoscopic surgery, single-incision transthoracic thoracoscopic surgery and three-incision transthoracic thoracoscopic surgery for spontaneous pneumothorax. Methods During the period August 2013 to September 2015, fifty-seven consecutive patients with spontaneous pneumothorax were treated via single-incision subxiphoid thoracoscopic surgery, single-incision transthoracic thoracoscopic surgery or three-incision transthoracic thoracoscopic surgery. Demographic data, operative time, operative blood loss, length of hospital stay, duration of chest tube drainage, postoperative complications, and numeric pain rating scale scores were collected from the medical records for analysis. Results Among the 57 patients, 14 received single-incision subxiphoid thoracoscopic surgery, 26 underwent single-incision transthoracic surgery and 17 received three-incision thoracoscopic surgery. In all patients, surgeries were completed without the need for conversion to open surgery. Patients who underwent the single-incision subxiphoid procedure had significantly lower 1-, 8-, 24- and 32-hour postoperative pain scale scores than patients who underwent the other two procedures. The average and maximum pain scale scores during the first 24 hours were lowest in the single-incision subxiphoid group (P<0.0001). Conclusions Single-incision subxiphoid thoracoscopic surgery is associated with significantly lower postoperative pain intensity than transthoracic approaches and therefore may provide an alternative surgical technique for patients with spontaneous pneumothorax. PMID:27014474

  11. A novel technique of anesthesia induction in supine position with impaled knife in the back

    PubMed Central

    Kumar, Ajay; Saha, Kamales Kumar; Jagiasi, Bharat; Saha, Kakalee K

    2015-01-01

    Current technique of airway management for impaled knife in the back includes putting the patient in lateral position and intubation. We present here a novel technique of anesthesia induction (intubation and central line insertion) in a patient with impaled knife in the back which is simple and easily reproducible. This technique can be used for single lung ventilation using double lumen tube or bronchial blocker also if desired. PMID:25849698

  12. A novel technique of anesthesia induction in supine position with impaled knife in the back.

    PubMed

    Kumar, Ajay; Saha, Kamales Kumar; Jagiasi, Bharat; Saha, Kakalee K

    2015-01-01

    Current technique of airway management for impaled knife in the back includes putting the patient in lateral position and intubation. We present here a novel technique of anesthesia induction (intubation and central line insertion) in a patient with impaled knife in the back which is simple and easily reproducible. This technique can be used for single lung ventilation using double lumen tube or bronchial blocker also if desired. PMID:25849698

  13. Peripheral dose measurement for CyberKnife radiosurgery with upgraded linac shielding.

    PubMed

    Chuang, Cynthia F; Larson, David A; Zytkovicz, Andrea; Smith, Vernon; Petti, Paula L

    2008-04-01

    The authors investigated the peripheral dose reduction for CyberKnife radiosurgery treatments after the installation of a linac shielding upgrade. As in a previous investigation, the authors considered two treatment plans, one for a hypothetical target in the brain and another for a target in the thorax, delivered to an anthropomorphic phantom. The results of the prior investigation showed that the CyberKnife delivered significantly higher peripheral doses than comparable model C Gamma Knife or IMRT treatments. Current measurements, after the linac shielding upgrade, demonstrate that the additional shielding decreased the peripheral dose, expressed as a percentage of the delivered monitor units (MU), by a maximum of 59%. The dose reduction was greatest for cranial-caudal distances from the field edge less than 30 cm, and at these distances, the CyberKnife peripheral dose, expressed as a percentage of the delivered MU, is now comparable to that measured for the other treatment modalities in our previous investigation. For distances between 30 and 70 cm from the field edge, the additional shielding reduced the peripheral dose by between 20% and 55%. At these distances, the CyberKnife peripheral dose remains higher than doses measured in our previous study for the model C Gamma Knife and IMRT. PMID:18491544

  14. Lifting incise drapes off the skin during wound closure can cause contamination.

    PubMed

    Makki, D; Probert, N; Gedela, V; Kustos, I; Thonse, R; Banim, R

    2015-05-01

    Incise drapes adhere well to skin and reduce bacterial migration into the wound. We took skin swabs before and after the application of incise drapes during 49 hip and knee arthroplasty procedures. Contamination was detected under incise drapes in four cases (8.1%) and consisted mainly of skin flora. We conclude that it is important to clean the skin again with antiseptics if the incise drape is removed by the surgeon. PMID:26292465

  15. Modified pocket incision: a simplified technique for astigmatism control and wound closure.

    PubMed

    Kansas, P G

    1989-01-01

    Advantages of small incision cataract surgery are widely known whether performed with phacoemulsification or manual fragmentation (phacofracture). A modified pocket incision technique that allows predictable astigmatism control without reliance on expensive intraoperative keratometers is described. This technique requires less dissection than the pocket incision and is less likely to bleed. PMID:2646435

  16. What can we learn from fluvial incision in high mountains?

    NASA Astrophysics Data System (ADS)

    Fuchs, Margret; Gloaguen, Richard; Krbetschek, Matthias

    2013-04-01

    High and actively deforming mountain ranges attract the attention of geoscientists as they provide natural laboratories of fast evolving process-response systems. Tectonic compressional settings, often linked to perpendicular extension, control the topographic growth and hence, erosion, transport pathways and sedimentation. High altitude differences within short horizontal distances promote material re-organisation and high rates of surface processes. Furthermore, high mountains constitute orographic barriers that affect atmospheric circulations as well as host different climate regimes similar to those of widely separated latitudinal belts. Both cause a high sensitivity of surface processes to changes in climatic conditions. However, feedbacks between climatic and tectonic forcing are complex. Additionally, the dominance of one or the other varies in space and also over time, inheriting various traces of the paleo-morphodynamic conditions to the subsequent process regimes. To unravel the forces driving the evolution of relief in active mountains, numerous studies employ the drainage network of the corresponding mountains as a proxy of landscape evolution. Especially the rates of river incision provide a powerful tool to characterize the surface response and infer causes behind it. Several parameters of river incision are available to describe the fluvial incision at individual sites (e.g. terrace incision rates), along the river course (e.g. longitudinal river profiles, Hack index) and in its perpendicular dimension (e.g. valley cross sections, valley shape ratios). But they require careful interpretation. They are sensitive to both, climatic and tectonic forcing. Therefore, the synopsis of such indices for fluvial incision is essential to evaluate the role of climatic versus tectonic forcing. Here, we use the Panj river system, the major river draining the Pamir mountains of Central Asia, as an example. The Panj experiences high altitude changes of more than 4000

  17. Big Blocks and River Incision: A Numerical Modeling Perspective

    NASA Astrophysics Data System (ADS)

    Shobe, C. M.; Tucker, G. E.; Anderson, R. S.

    2015-12-01

    Sediment supply dynamics affect fluvial erosion in steep landscapes. Workers have explored the effects of changing sediment flux and uniform grain size on incision processes and distribution of alluvial cover. However, sediment supplied to real rivers is often highly heterogeneous in size, especially in rapidly eroding landscapes where supply processes may range from landslides to rockfall to moraine incision. We hypothesize that the pace of landscape evolution depends on the sediment size distribution supplied to rapidly eroding channels. Rivers that quickly cut steep-walled canyons may incite a negative feedback on incision by receiving an increased supply of large, immobile blocks from the canyon walls that shield significant portions of the bed from erosion. We use a 1-D numerical model that combines mass-flux continuum treatment of several grain size classes with tracking of discrete large blocks to explore fluvial response to changing grain size distribution. We compare simulations with and without a feedback between channel incision rate and the supply rate of large blocks from adjacent hillslopes. This reflects the hypothesis that slopes will be steeper and more prone to releasing large blocks when the channel at their base is eroding rapidly. Comparing model predictions with field observations shows that our models can successfully reproduce the distribution of blocks in natural channels. Results suggest that in landscapes with access to large blocks, fluvial incision may be slowed as increasing amounts of immobile material are supplied from adjacent hillslopes and canyon walls. This can act to stall knickpoint retreat in such rivers and slow the pace of landscape adjustment. The importance of channel armoring by blocks is governed by competition between two timescales: the time required for significant block cover to accumulate in the channel and the time required for blocks to abrade, fragment, or weather down to transportable sizes. Model results also

  18. Differential Uplift and Incision of the Yakima River Terraces

    NASA Astrophysics Data System (ADS)

    Bender, A. M.; Amos, C. B.; Bierman, P. R.; Rood, D. H.; Sorsby, S. J.; Kelsey, H. M.; Ladinsky, T. C.

    2014-12-01

    The Yakima fold and thrust belt comprises 12 reverse-faulted folds deforming Miocene basalts of the ~14,000 km2 Columbia River Plateau in central Washington State. Contemporary N to NE-directed shortening of ~1-2 mm/yr occurs across the belt, but the distribution of Quaternary deformation among the individual Yakima folds and faults is unclear. The Yakima River incises roughly normal to several of these structures south of Ellensburg, WA, where topography mimics structural relief and fluvial incision may be a proxy for differential rock uplift. Here, we combine LiDAR analysis, field mapping, and cosmogenic isochron burial ages of gravels above strath terraces to quantify the rate of Quaternary incision through two of these folds, Manastash and Umtanum Ridges. We mapped terraces flanking the Yakima River at five levels—individual terraces consist of mixed rock-type river gravel deposits capping basalt straths. We sampled eight terrace gravels for isochron burial dating utilizing cosmogenic 10Be and 26Al to determine terrace ages and calculate incision rates. Preliminary isochron burial ages from two sampled terraces yield mid-to-early Quaternary ages for terraces ~60 and ~15 m above the modern Yakima River (1.08 ± 0.29 Ma and 1.59 ± 0.25 Ma, respectively). Although these ages overlap within error (1s), the younger, higher terrace lies within the core of the Manastash Ridge anticline, while the lower, older deposit occurs in the intervening syncline north of Umtanum Ridge. Corresponding incision rates are < 0.10 mm/yr, and are consistent with differential uplift of the Manastash Ridge anticline, despite large age uncertainties resulting from the narrow range of relatively low 10Be concentrations for analyzed samples. We are processing additional samples to reduce burial age uncertainties, and characterize incision and uplift rates on six more strath terraces spanning heights of ~5-100 m above the active channel, distributed across the Manastash and Umtanum Ridge

  19. Dielectric relaxation time spectroscopy.

    PubMed

    Paulson, K S; Jouravleva, S; McLeod, C N

    2000-11-01

    A new mathematical method is developed to recover the permittivity relaxation spectrum of living tissue from measurements of the real and imaginary parts of the impedance. Aiming to derive information about electrical properties of living tissue without the prior selection of any impedance model, the procedure calculates the relaxation time distribution. It provides new characteristic independent parameters: time constants, their distribution, and the amplitudes of the associated dispersion. As the beta-dispersion is the most important in the area of electrical impedance spectroscopy of tissue, the paper gives an estimate of the essential frequency range to cover the whole relaxation spectrum in that area. Results are presented from both simulation and known lumped--constant element circuit. PMID:11077745

  20. Observation of Phase Objects by Using an X-ray Microscope with a Foucault Knife-Edge

    SciTech Connect

    Watanabe, N.; Sasaya, T.; Imai, Y.; Iwata, S.; Zama, K.; Aoki, S.

    2011-09-09

    An x-ray microscope with a zone plate was assembled at the synchrotron radiation source of BL3C, Photon Factory. A Foucault knife-edge was set at the back focal plate of the objective zone plate and phase retrieval was tested by scanning the knife-edge. A preliminary result shows that scanning the knife-edge during exposure was effective for phase retrieval. Phase-contrast tomography was investigated using differential projection images calculated from two Schlieren images with the oppositely oriented knife-edges. Fairly good reconstruction images of polystyrene beads and spores could be obtained.

  1. Observation of Phase Objects by Using an X-ray Microscope with a Foucault Knife-Edge

    NASA Astrophysics Data System (ADS)

    Watanabe, N.; Sasaya, T.; Imai, Y.; Iwata, S.; Zama, K.; Aoki, S.

    2011-09-01

    An x-ray microscope with a zone plate was assembled at the synchrotron radiation source of BL3C, Photon Factory. A Foucault knife-edge was set at the back focal plate of the objective zone plate and phase retrieval was tested by scanning the knife-edge. A preliminary result shows that scanning the knife-edge during exposure was effective for phase retrieval. Phase-contrast tomography was investigated using differential projection images calculated from two Schlieren images with the oppositely oriented knife-edges. Fairly good reconstruction images of polystyrene beads and spores could be obtained.

  2. The incision-excision technique in minor auricular deformities.

    PubMed

    Heppt, Werner J

    2004-11-01

    In 1972, in the search for a method to cope with all deformities in protruding ears and other common minor auricular deformities, Claus Walter published a surgical technique based on various incisions and excisions of the cartilage. The procedure consists of a complete separation of the auricle into two parts, combined with remodeling of antihelical, helical, and lobular structures without use of adjusting sutures. Thus, even in patients with stiff and unyielding cartilage and in revisional surgery, pleasing aesthetic results may be achieved. The recurrence rate has found to be reduced markedly. Considering all pros and cons and optional surgical modifications, the incision-excision technique can be adopted for every protruding ear as well as for lop ears, moderate cup ear deformities, and secondary revisions. Because of the extent of cartilage dissection, this technique is not recommended for beginners but should be restricted to experienced surgeons with profound knowledge of basic remodeling procedures. PMID:15778916

  3. Small-incision manual extracapsular cataract extraction using selective hydrodissection.

    PubMed

    Blumenthal, M; Ashkenazi, I; Assia, E; Cahane, M

    1992-10-01

    Hydrodissection is a technique in which balanced salt solution is injected through a cannula into various layers of a cataractous lens to separate the lens lamella in a nonspecific location. Selective hydrodissection allows separation of the lens lamella at different desired anatomical layers. The technique allows the smallest possible nucleus, ie, the hard-core nucleus, to be hydroexpressed as a separate entity, requiring, correspondingly, a relatively small capsulorhexis and limbal incision. Then, in a second maneuver, the epinucleus, which engulfs the hardcore nucleus to form the adult nucleus, also can be aspirated or hydroexpressed as a whole. Selective hydrodissection permits scleral incision and stitchless surgery in planned extracapsular cataract extraction and also may serve as an intermediate step for surgeons who wish to convert to or learn phacoemulsification techniques. PMID:1436973

  4. Resonant Laser Incisions: Molecular Targets Using the Free Electron Laser

    NASA Astrophysics Data System (ADS)

    Reinisch, Lou; Bryant, Grady; Ossoff, Robert H.

    1996-03-01

    Laser ablation of tissue for medical incisions is normally concerned with the energy absorption and the subsequent vaporization of intracellular water. Using Fourier transform infrared spectroscopy, we have identified specific non-water resonances within tissues. Then, using the Vanderbilt Free Electron Laser (wavelength tunable from 2 to 10 microns) and our Computer Assisted Surgical Techniques program (to standardize the laser delivery), we have targeted specific molecular resonances for laser incisions and tissue removal. Using both acute and chronic studies, we can map out the resonant action spectrum to improve surgical outcomes. We have modeled these ablation mechanisms and working to establish the link between these ablation mechanisms and wound healing. This work has been supported, in part, by a grant from the Department of Defense, Medical Free Electron Laser Program, ONR Grant #N000149411023.

  5. Dual-incision laparoscopic spleen-preserving distal pancreatectomy

    PubMed Central

    Kim, Eun Young; You, Young Kyoung; Kim, Dong Goo; Lee, Soo Ho; Han, Jae Hyun; Park, Sung Kyun; Na, Gun Hyung

    2015-01-01

    Laparoscopic spleen-preserving distal pancreatectomy has been widely performed for benign and borderline malignancy in the body or tail of the pancreas when there are not oncologic indications for splenectomy. As the need for minimally invasive procedures to reduce postoperative morbidity and improve the quality of life is increasing, many surgeons have attempted to reduce the number of trocars and incision size to minimize access trauma and scarring. Single-port laparoscopic spleen-preserving distal pancreatectomy is the result of these efforts; however it has many limitations such as technical difficulty and prolonged operation time. In this article, we report the first case of dual-incision laparoscopic spleen-preserving distal pancreatectomy, proving that it can be a safe and feasible minimally invasive procedure for benign or borderline malignant tumors in the body or tail of the pancreas. PMID:25741499

  6. Modified Lanz incision in appendicectomy - the surgical trainees best friend.

    PubMed

    O'Neill, S; Abdelaziz, E A; Andrabi, S I

    2010-01-01

    Appendicitis is one of the commonest acute surgical diseases and treatment by appendicectomy is the most frequently performed surgical procedure in the western world. After obtaining adequate basic surgical experience, an open appendicectomy is an ideal procedure for junior surgical trainees to develop their operative skills and despite a reduction in training hours, recent figures suggest that surgical SHOs still perform about 30% of these cases. Although they are clearly routine and suitable for junior staff to perform under supervision, as many as 20% of appendicectomies, are for a variety of reasons considered difficult. We aim to be the first to present a modified Lanz incision that we believe provides not only a cosmetic scar but also is placed more frequently over the base of the appendix. It gives adequate access in difficult cases and we feel this is the most appropriate incision for a trainee to use when performing an appendicectomy. PMID:19897062

  7. Gamma Knife radiosurgery with CT image-based dose calculation.

    PubMed

    Xu, Andy Yuanguang; Bhatnagar, Jagdish; Bednarz, Greg; Niranjan, Ajay; Kondziolka, Douglas; Flickinger, John; Lunsford, L Dade; Huq, M Saiful

    2015-01-01

    The Leksell GammaPlan software version 10 introduces a CT image-based segmentation tool for automatic skull definition and a convolution dose calculation algorithm for tissue inhomogeneity correction. The purpose of this work was to evaluate the impact of these new approaches on routine clinical Gamma Knife treatment planning. Sixty-five patients who underwent CT image-guided Gamma Knife radiosurgeries at the University of Pittsburgh Medical Center in recent years were retrospectively investigated. The diagnoses for these cases include trigeminal neuralgia, meningioma, acoustic neuroma, AVM, glioma, and benign and metastatic brain tumors. Dose calculations were performed for each patient with the same dose prescriptions and the same shot arrangements using three different approaches: 1) TMR 10 dose calculation with imaging skull definition; 2) convolution dose calculation with imaging skull definition; 3) TMR 10 dose calculation with conventional measurement-based skull definition. For each treatment matrix, the total treatment time, the target coverage index, the selectivity index, the gradient index, and a set of dose statistics parameters were compared between the three calculations. The dose statistics parameters investigated include the prescription isodose volume, the 12 Gy isodose volume, the minimum, maximum and mean doses on the treatment targets, and the critical structures under consideration. The difference between the convolution and the TMR 10 dose calculations for the 104 treatment matrices were found to vary with the patient anatomy, location of the treatment shots, and the tissue inhomogeneities around the treatment target. An average difference of 8.4% was observed for the total treatment times between the convolution and the TMR algorithms. The maximum differences in the treatment times, the prescription isodose volumes, the 12 Gy isodose volumes, the target coverage indices, the selectivity indices, and the gradient indices from the convolution

  8. Lung Resection Using Transumbilical Incision: An Animal Survival Study

    PubMed Central

    Yin, Shun-Ying; Yen-Chu; Wu, Yi-Cheng; Liu, Chien-Ying; Hsieh, Ming-Ju; Yuan, Hsu-Chia; Ko, Po-Jen

    2015-01-01

    Introduction: Transumbilical single-port surgery is a potentially less invasive approach to many types of abdominal surgeries and offers better cosmetic outcomes than conventional 3-port laparoscopic surgery. It avoids the complication of intercostal neuralgia and may reduce the risk of pulmonary complications after video-assisted thoracic surgery. This study evaluated the feasibility of transumbilical lung wedge resection. Methods: Lung resection was performed in 11 beagle dogs weighing 5.9 to 8.5 kg. A 3-cm umbilical incision and one diaphragmatic incision were made, and an endoscopic stapler was used. The diaphragmatic incisions were repaired under video guidance using a V-Loc knotless suturing device (Covidien, Mansfield, Massachusetts). Animals were monitored daily for signs of postoperative infection. White blood cell count, C-reactive protein level, and IL-6 level were measured in all animals. Animals were euthanized 14 days after surgery and underwent necropsy evaluation. Results: Accurate lung resection was achieved in 10 of 11 animals during a median operative time of 98 minutes (range 60–165). In 1 animal, transumbilical lung resection was not possible and was converted to thoracotomy. All animals survived without major postoperative complications. At necropsy, evidence of uneventful healing of the stapled resection margin and diaphragmatic wound were found. There was no evidence of vital organ injury or intrathoracic infection. Conclusion: A transumbilical approach to thoracic cavity exploration and stapled lung resection is technically feasible. Primary suturing of the diaphragmatic incision is a simple and effective means of diaphragmatic wound closure. This may be an alternative to video-assisted thoracic surgery for the management of simple thoracic disease. PMID:25848173

  9. Single-Incision Laparoscopic Colon and Rectal Surgery

    PubMed Central

    Keller, Deborah S.; Haas, Eric M.

    2015-01-01

    Single-incision laparoscopic surgery (SILS) was introduced to further the enhanced outcomes of multiport laparoscopy. Multiple studies have demonstrated the safety and feasibility of SILS for both benign and malignant colorectal disease. SILS provides the potential for improved cosmesis, postoperative outcomes, and patient quality of life. However, widespread use has been limited by technical demands and lack of an evidence and competency-based curriculum. PMID:26491404

  10. Mini incision open pyeloplasty - Improvement in patient outcome

    PubMed Central

    Singh, Vishwajeet; Garg, Manish; Sharma, Pradeep; Sinha, Rahul Janak; Kumar, Manoj

    2015-01-01

    ABSTRACT Purpose: To assess the subjective and objective outcomes of mini-incision dismembered Anderson-Hynes pyeloplasty in the treatment of primary ureteropelvic junction obstruction (UPJO). Materials and Methods: Between January 2008 to January 2013, Anderson-Hynes pyeloplasty was performed in 71 patients diagnosed with primary UPJO. Small subcostal muscle splitting incision was used in all cases. Sixteen patients with renal calculi underwent concomitant pyelolithotomy. Subjective outcome was assessed using visual pain analogue score (VAS). For objective assessment, the improvement in differential renal function (DRF) and radio-tracer wash out time (T1/2) on Tc-99m DTPA scan and decrease in hydronephrosis (HDN) on renal ultrasound (USG) and urography (IVU) were assessed. Results: Mean incision length was 5.2 cm. The average operating time and postoperative hospital stay was 63 (52-124) minutes and 2.5 (2–6) days respectively. Concomitant renal calculi were successfully removed in all the patients. Overall complication rates were 8.4% and overall success rate was 98.6% at median follow-up of 16 months. There was significant improvement in pain score (p=0.0001) and significant decrease in HDN after the procedure. While preoperative mean T1/2 was 26.7±6.4 minutes, postoperative half-time decreased to 7.8±4.2 minutes at 6 months and to 6.7±3.3 minutes at 1 year. Mean pre-operative DRF was 26.45% and it was 31.38% and 33.19% at 6 months and 1 year respectively. Conclusions: Mini-incision pyeloplasty is a safe and effective technique with combined advantage of high success rates of standard open pyeloplasty with decreased morbidity of laparoscopic approach. Excellent functional and objective outcomes can be achieved without extra technical difficulty. PMID:26689518

  11. Pleistocene drainage incision in the upper Mississippi Valley Driftless Area

    SciTech Connect

    Knox, J.C.

    1985-01-01

    The deep dissection of the Wisconsin Driftless Area and topographically similar, but glaciated areas in adjacent states is generally acknowledged to have occurred during the Pleistocene, but the precise chronology has been poorly understood. The distribution of pre-Illinoian glacial outwash gravels on uplands and valley side benches near the Mississippi River, on the western margin of the Wisconsin Driftless Area, indicates that the major incision (50-60 m) of drainage had occurred during the very early Pleistocene. Deposits in cut-off valley meanders, a common feature in the lower reaches of Driftless Area rivers, provide a basis for relative dating of the valley incision. The cut-offs appear to have evolved episodically when, at various times during the Pleistocene, glacial debris blocked the drainages of the Mississippi and Wisconsin Rivers causing massive alluviation of side valley tributaries. A radiocarbon date of 21,910 +/- 350 year B.P., representing a buried soil horizon at 22 m depth and about 9 m above the bedrock floor of a cut-off valley meander and 18 m above the bedrock floor of the adjacent present-day valley, supports stratigraphic interpretations that suggest modest valley incision into bedrock probably occurred during the Illinoian and may have also occurred during the early Wisconsinan.

  12. Bedrock incision by bedload: insights from direct numerical simulations

    NASA Astrophysics Data System (ADS)

    Aubert, Guilhem; Langlois, Vincent J.; Allemand, Pascal

    2016-04-01

    Bedload sediment transport is one of the main processes that contribute to bedrock incision in a river and is therefore one of the key control parameters in the evolution of mountainous landscapes. In recent years, many studies have addressed this issue through experimental setups, direct measurements in the field, or various analytical models. In this article, we present a new direct numerical approach: using the classical methods of discrete-element simulations applied to granular materials, we explicitly compute the trajectories of a number of pebbles entrained by a turbulent water stream over a rough solid surface. This method allows us to extract quantitatively the amount of energy that successive impacts of pebbles deliver to the bedrock, as a function of both the amount of sediment available and the Shields number. We show that we reproduce qualitatively the behaviour observed experimentally by Sklar and Dietrich (2001) and observe both a "tool effect" and a "cover effect". Converting the energy delivered to the bedrock into an average long-term incision rate of the river leads to predictions consistent with observations in the field. Finally, we reformulate the dependency of this incision rate with Shields number and sediment flux, and predict that the cover term should decay linearly at low sediment supply and exponentially at high sediment supply.

  13. Surgical robot for single-incision laparoscopic surgery.

    PubMed

    Choi, Hyundo; Kwak, Ho-Seong; Lim, Yo-An; Kim, Hyung-Joo

    2014-09-01

    This paper introduces a novel surgical robot for single-incision laparoscopic surgeries. The robot system includes the cone-type remote center-of-motion (RCM) mechanism and two articulated instruments having a flexible linkage-driven elbow. The RCM mechanism, which has two revolute joints and one prismatic joint, is designed to maintain a stationary point at the apex of the cone shape. By placing the stationary point on the incision area, the mechanism allows a surgical instrument to explore the abdominal area through a small incision point. The instruments have six articulated joints, including an elbow pitch joint, which make the triangulation position for the surgery possible inside of the abdominal area. The presented elbow pitch structure is similar to the slider-crank mechanism but the connecting rod is composed of a flexible leaf spring for high payload and small looseness error. We verified the payload of the robot is more than 10 N and described preliminary experiments on peg transfer and suture motion by using the proposed surgical robot. PMID:24835120

  14. Erosive dynamics of channels incised by subsurface water flow

    NASA Astrophysics Data System (ADS)

    Lobkovsky, Alexander E.; Smith, Braunen E.; Kudrolli, Arshad; Mohrig, David C.; Rothman, Daniel H.

    2007-09-01

    We propose a dynamical model for channels incised into an erodible bed by subsurface water flow. The model is validated by the time-resolved topographic measurements of channel growth in a laboratory-scale experiment. Surface heights in the experiment are measured via a novel laser-aided imaging technique. The erosion rate in the model is composed of diffusive and advective components as well as a simple driving term due to the seeping water. Steady driving conditions may exist whenever channels are incised into a flat and level erodible bed by a water table replenished via steady (on average) rainfall. Under such steady driving conditions, the model predicts an asymptotically self-similar growing shape for the channel transects. Conversely, given a transect shape that evolved under steady driving conditions and an estimate of the erosion rate at the bottom of the channel, granular transport coefficients can be inferred from the static channel shape. We report an estimate of these transport coefficients for a system of ravines incised into unconsolidated sand in the Apalachicola River basin, Florida.

  15. Air kerma based dosimetry calibration for the Leksell Gamma Knife

    SciTech Connect

    Meltsner, Sheridan Griffin; DeWerd, Larry A.

    2009-02-15

    No accepted official protocol exists for the dosimetry of the Leksell Gamma Knife registered (GK) stereotactic radiosurgery device. Establishment of a dosimetry protocol has been complicated by the unique partial-hemisphere arrangement of 201 individual {sup 60}Co beams simultaneously focused on the treatment volume and by the rigid geometry of the GK unit itself. This article proposes an air kerma based dosimetry protocol using either an in-air or in-acrylic phantom measurement to determine the absorbed dose rate of fields of the 18 mm helmet of a GK unit. A small-volume air ionization chamber was used to make measurements at the physical isocenter of three GK units. The absorbed dose rate to water was determined using a modified version of the AAPM Task Group 21 protocol designed for use with {sup 60}Co-based teletherapy machines. This experimentally determined absorbed dose rate was compared to the treatment planning system (TPS) absorbed dose rate. The TPS used with the GK unit is Leksell GammaPlan. The TPS absorbed dose rate at the time of treatment is the absorbed dose rate determined by the physicist at the time of machine commissioning decay corrected to the treatment date. The TPS absorbed dose rate is defined as absorbed dose rate to water at the isocenter of a water phantom with a radius of 8 cm. Measurements were performed on model B and C Gamma Knife units. The absorbed dose rate to water for the 18 mm helmet determined using air-kerma based calculations is consistently between 1.5% and 2.9% higher than the absorbed dose rate provided by the TPS. These air kerma based measurements allow GK dosimetry to be performed with an established dosimetry protocol and without complications arising from the use of and possible variations in solid phantom material. Measurements were also made with the same ionization chamber in a spherical acrylic phantom for comparison. This methodology will allow further development of calibration methods appropriate for the

  16. Size reduction of high- and low-moisture corn stalks by linear knife grid system

    SciTech Connect

    Womac, A.R.; Igathinathane, C.; Sokhansanj, Shahabaddine; Narayan, S.

    2009-04-01

    High- and low-moisture corn stalks were tested using a linear knife grid size reduction device developed for first-stage size reduction. The device was used in conjunction with a universal test machine that quantified shearing stress and energy characteristics for forcing a bed of corn stalks through a grid of sharp knives. No published engineering performance data for corn stover with similar devices are available to optimize performance; however, commercial knife grid systems exist for forage size reduction. From the force displacement data, mean and maximum ultimate shear stresses, cumulative and peak mass-based cutting energies for corn stalks, and mean new surface area-based cutting energies were determined from 4 5 refill runs at two moisture contents (78.8% and 11.3% wet basis), three knife grid spacings (25.4, 50.8, and 101.6 mm), and three bed depths (50.8, 101.6, and 152.4 mm). In general, the results indicated that peak failure load, ultimate shear stress, and cutting energy values varied directly with bed depth and inversely with knife grid spacing. Mean separation analysis established that high- and low-moisture conditions and bed depths 101.6 mm did not differ significantly (P < 0.05) for ultimate stress and cutting energy values, but knife grid spacing were significantly different. Linear knife grid cutting energy requirements for both moisture conditions of corn stalks were much smaller than reported cutting energy requirements. Ultimate shear stress and cutting energy results of this research should aid the engineering design of commercial scale linear knife gird size reduction equipment for various biomass feedstocks.

  17. RELAX: detecting relaxed selection in a phylogenetic framework.

    PubMed

    Wertheim, Joel O; Murrell, Ben; Smith, Martin D; Kosakovsky Pond, Sergei L; Scheffler, Konrad

    2015-03-01

    Relaxation of selective strength, manifested as a reduction in the efficiency or intensity of natural selection, can drive evolutionary innovation and presage lineage extinction or loss of function. Mechanisms through which selection can be relaxed range from the removal of an existing selective constraint to a reduction in effective population size. Standard methods for estimating the strength and extent of purifying or positive selection from molecular sequence data are not suitable for detecting relaxed selection, because they lack power and can mistake an increase in the intensity of positive selection for relaxation of both purifying and positive selection. Here, we present a general hypothesis testing framework (RELAX) for detecting relaxed selection in a codon-based phylogenetic framework. Given two subsets of branches in a phylogeny, RELAX can determine whether selective strength was relaxed or intensified in one of these subsets relative to the other. We establish the validity of our test via simulations and show that it can distinguish between increased positive selection and a relaxation of selective strength. We also demonstrate the power of RELAX in a variety of biological scenarios where relaxation of selection has been hypothesized or demonstrated previously. We find that obligate and facultative γ-proteobacteria endosymbionts of insects are under relaxed selection compared with their free-living relatives and obligate endosymbionts are under relaxed selection compared with facultative endosymbionts. Selective strength is also relaxed in asexual Daphnia pulex lineages, compared with sexual lineages. Endogenous, nonfunctional, bornavirus-like elements are found to be under relaxed selection compared with exogenous Borna viruses. Finally, selection on the short-wavelength sensitive, SWS1, opsin genes in echolocating and nonecholocating bats is relaxed only in lineages in which this gene underwent pseudogenization; however, selection on the functional

  18. Relaxation techniques for stress

    MedlinePlus

    ... Know. February 2013. Available at: nccih.nih.gov/health/stress/relaxation.htm . Accessed September 21, 2015. National Center ... A.D.A.M. Editorial team. Related MedlinePlus Health Topics Stress Browse the Encyclopedia A.D.A.M., Inc. ...

  19. Bedrock River Incision Following Aggradation: Observations from the Waipaoa River Regarding Tributary Response to Mainstem Incision and the Role of Paleotopography

    NASA Astrophysics Data System (ADS)

    Crosby, B. T.; Whipple, K. X.

    2005-12-01

    Following a period of valley-filling aggradation, the form and extent of subsequent alluvial and bedrock incision is governed by the pre-aggradation topography and the position of the channel at the time of incision. We present findings from an extensive along-stream survey of the Waihuka Stream, a tributary to the Waipaoa River on the North Island of New Zealand. Never glaciated, this basin aggraded 5 to 25 m of coarse alluvial sediment during the last glacial period, creating an extensive and distinctive valley-fill surface. ~18 ka, aggradation ceased and a subsequent pulse of fluvial incision abandoned the aggradational surface. At present, the river gorge is incised 25 to 60 m into alluvial fill and mudstone bedrock beneath the top of the aggradational surface. Using a laser range-finder and GPS-enabled GIS surveying tool, we surveyed ~17 km of the Waihuka Stream (4.8×106 m2 to 6.3×107 m2). We collected a longitudinal profile and the relative elevations of fill and strath surfaces exposed in channel banks. We also surveyed a total of ~9 km in 14 tributaries to the Waihuka. Drainage areas of tributaries ranged between 5×105 m2 and 9.9×106 m2. In the Waihuka, we find that the amount of bedrock incision depends on whether the incising channel locally lowered through alluvial fill to reoccupy the preaggradation channel or whether it locally had to cut an entirely new valley into bedrock. Reaches dominated by bedrock incision were observed where alluvial fan deposits laterally shifted the mainstem channel out of the paleovalley and against the opposite bedrock hillslope. The along-stream variation in bed erodability forced by whether the re-incising channel encountered bedrock or alluvium had a significant effect on the propagation of the incision signal into tributaries. Where the channel dominantly re-incised alluvial fill, tributaries have stepped but not dramatically over-steepened longitudinal profiles that appear to be adjusting to the new base-level. In

  20. Measurement of Gamma Knife registered helmet factors using MOSFETs

    SciTech Connect

    Kurjewicz, Laryssa; Berndt, Anita

    2007-03-15

    The relative dose rate for the different Gamma Knife registered helmets (4, 8, 14, and 18 mm) is characterized by their respective helmet factors. Since the plateau of the dose profile for the 4 mm helmet is at most 1 mm wide, detector choices are limited. Traditionally helmet factors have been measured using 1x1x1 mm{sup 3} thermoluminescent dosimeters (TLDs). However, these are time-consuming, cumbersome measurements. This article investigates the use of metal-oxide-semiconductor field effect transistors (MOSFETs) (active area of 0.2x0.2 mm{sup 2}) as a more accurate and convenient dosimeter. Their suitability for these measurements was confirmed by basic characterization measurements. Helmet factors were measured using both MOSFETs and the established TLD approach. A custom MOSFET cassette was designed in analogy to the Elekta TLD cassette (Elekta Instruments AB) for use with the Elekta dosimetry sphere. Although both dosimeters provided values within 3% of the manufacturer's suggestion, MOSFETs provided superior accuracy and precision, in a fraction of the time required for the TLD measurements. Thus, MOSFETs proved to be a reasonable alternative to TLDs for performing helmet factor measurements.

  1. Gamma Knife radiosurgery for the treatment of cavernous sinus hemangiomas

    PubMed Central

    XU, QINGSHENG; SHEN, JIAN; FENG, YIPING; ZHAN, RENYA

    2016-01-01

    The present retrospective study aimed to analyze the outcome of patients with cavernous sinus hemangioma (CSH) treated with Gamma Knife radiosurgery (GKS). Between August 2011 and April 2014, 7 patients with CSHs underwent GKS. GKS was performed as the sole treatment option in 5 patients, whilst partial resection had been performed previously in 1 patient and biopsy had been performed in 1 patient. The mean volume of the tumors at the time of GKS was 12.5±10.2 cm3 (range, 5.3–33.2 cm3), and the median prescription of peripheral dose was 14.0 Gy (range, 10.0–15.0 Gy). The mean follow-up period was 20 months (range, 6–40 months). At the last follow-up, the lesion volume had decreased in all patients, and all cranial neuropathies observed prior to GKS had improved. There were no radiation-induced neuropathies or complications during the follow-up period. GKS appears to be an effective and safe treatment modality for the management of CSHs. PMID:26893777

  2. Class characteristics of serrated knife stabs to cartilage.

    PubMed

    Pounder, Derrick J; Cormack, Lesley; Broadbent, Elizabeth; Millar, John

    2011-06-01

    A total of 136 stab wounds were made in cartilage with 8 serrated knives and 72 stabs with 4 nonserrated knives. The walls of the stab track were documented by photography, cast with dental impression material, and the casts photographed. Staining the translucent cartilage surface with blue or green food dye improved photography. Serrated blades produced striations on cartilage in all stabbings. Patterns of blade serration beyond the broad categories of coarse and fine were recognizable. The overall pattern of striations was "irregularly regular." The distance between the blade-spine wound end and the first serration striation is a class characteristic of the knife which produced the defect, as are distances to the subsequent serration striations, which become ever close together and eventually merge near the blade-edge wound end. Serrated knives may be ground (scalloped) on either the left side or the right side of the blade and this class characteristic is identifiable from the walls of the wound track, on which the scalloped blade surface produces broad ridges and narrow striation valleys, with a reverse image on the opposing wound wall. A drop point serrated blade consistently produced an additional oblique mark angled from the blade-spine wound end, accurately reflecting the shape of the blade tip, and representing a chatter mark. PMID:20407362

  3. Ruptured Pseudoaneurysm after Gamma Knife Surgery for Vestibular Schwannoma

    PubMed Central

    MURAKAMI, Mamoru; KAWARABUKI, Kentaro; INOUE, Yasuo; OHTA, Tsutomu

    2016-01-01

    Ruptured aneurysms of anterior inferior cerebellar artery (AICA) after radiotherapy for vestibular schwannoma (VS) are rare, and no definite treatment has been established for distal AICA pseudoaneurysms. We describe a 61-year-old man who underwent Gamma Knife surgery (GKS) for left VS. Follow-up magnetic resonance imaging (MRI) revealed partial regression of the tumor. Twelve years after GKS, he suffered from subarachnoid hemorrhage. Initial angiogram showed no vascular lesions; second left vertebral angiogram, 10 days after admission, demonstrated a pseudoaneurysm in the lateral pontine segment of the left AICA. The proximal portion of the AICA was occluded by a coil. Postoperative MRI revealed an infarction on the left side of the pons and brachium pontis. Although the patient suffered from mild postoperative cerebellar ataxia and facial and abducens nerve palsy, he was discharged 1 month postoperatively requiring no assistance with activities of daily living. Twelve months later, he recovered satisfactorily with a modified Rankin Scale grade of 1, and no recanalization of the aneurysm was found on MR angiography. Endovascular parent artery occlusion for ruptured aneurysms at distal AICA carries the risk of brain stem infarction, but should be considered when no other option is available such as after radiotherapy for VS. PMID:26667081

  4. Numerical modeling of tectonically driven river dynamics and deposition in an upland incised valley

    NASA Astrophysics Data System (ADS)

    Bianchi, Valeria; Salles, Tristan; Ghinassi, Massimiliano; Billi, Paolo; Dallanave, Edoardo; Duclaux, Guillaume

    2015-07-01

    Within upstream reaches of incised valleys, fluvial sedimentation occurs where it is controlled by interaction between climate and tectonics. This study focuses on a Plio-Pleistocene fluvial paleovalley, which drained the northeastern margin of Siena basin (northern Apennines, Italy). Valley filling resulted from the interaction between river drainage and active normal faults striking perpendicular and parallel to the main valley. Through numerical modeling, this study aims to refine temporal and spatial mesoscale deposit variations, which highlight the upset of fluvial architectures derived from the interplay between the river system and uplift. Geomorphological and hydrodynamic parameter calibration was performed integrating field studies with paleohydraulic and paleomagnetic data. The numerical model simulates the evolution of valley formation with the development of (i) a pre-tectonic steady state system, followed by (ii) a syntectonic aggradation and avulsion phase, and (iii) a post-tectonic relaxation phase. The syntectonic phase shows fine sediment back-filling upstream of the uplifted area and coarse sediment down-filling downstream of the upwarping. The recorded aggradations are asynchronous with upstream deposition preceding downstream deposition.

  5. Some effects of the microtome knife and electron beam on methacrylate-embedded thin sections.

    PubMed

    MOORE, D H; MORGAN, C; ROSE, H M

    1956-07-25

    A technique for the examination of specimens at low electron beam intensity has been presented. Sections micrographed with this technique showed numerous knife scratches and frequently contained bands running parallel to the knife edge. Banding with an average spacing of 0.2 micro appeared to result from periodic distortion produced by impact of the knife. At the beam intensities customarily employed, differential sublimation and probably flow of the methacrylate resulted in obliteration of the bands and all but the deepest knife scratches. In addition, changes in the size, shape, and orientation of certain structures were noted. Artifacts resulting from incineration or sublimation of tissue components fixed in formalin were illustrated, and the suggestion was made that such instability to the electron beam accounted in part for the differences observed in osmium- and formalin-fixed tissues. The deformation revealed in serial sections was discussed, and it was pointed out that shortening in the axis perpendicular to the knife edge was associated with elongation in the axis parallel to the cutting edge, the elongation usually occurring locally without change in the width of the section. It was noted that the material causing contamination of the surface of sections during examination exhibited no structure but caused progressive loss of contrast. PMID:13357516

  6. Shielding requirements on-site loading and acceptance testing on the Leksell gamma knife.

    PubMed

    Maitz, A H; Lunsford, L D; Wu, A; Lindner, G; Flickinger, J C

    1990-02-01

    On August 14, 1987, the first stereotactic radiosurgical procedure using the gamma knife was performed in North America. Located in a self-contained radiosurgical suite in the basement of Presbyterian-University Hospital in Pittsburgh, Pennsylvania. This device uses 201 highly focused beams 60Co for the single-treatment closed-skull irradiation of brain lesions localized by stereotactic techniques (radiosurgery). One hundred and fifty-two patients with intracranial arteriovenous malformations or brain tumors were treated in the first year of operation. The Presbyterian University Hospital of Pittsburgh gamma knife is the first such unit in which the 60Co sources were loaded on-site. This effort required us to solve some difficult and unusual problems encountered during site preparation, delivery, and loading of the unit in a busy hospital setting. The solutions developed enabled installation and use of the gamma knife with minimal disruption of hospital activities while maintaining acceptable levels of exposure to radiation. Environmental surveys performed during the loading of the 201 radioactive sources (total, 219 TBq) confirmed that on-site loading is possible and practical. Our experience in the design, construction, and implementation of the first North American gamma knife supports the practicality and safety of on-site loading and may be of value in the planning and development of future gamma knife installations. PMID:2406231

  7. Hair Dye and Hair Relaxers

    MedlinePlus

    ... For Consumers Consumer Information by Audience For Women Hair Dye and Hair Relaxers Share Tweet Linkedin Pin it More sharing ... products. If you have a bad reaction to hair dyes and relaxers, you should: Stop using the ...

  8. Influence of Incision Location on Transmitter Loss, Healing, Survival, Growth, and Suture Retention of Juvenile Chinook Salmon

    SciTech Connect

    Panther, Jennifer L.; Brown, Richard S.; Gaulke, Greg L.; Deters, Katherine A.; Woodley, Christa M.; Eppard, M. Brad

    2011-11-01

    Fisheries research involving surgical implantation of transmitters necessitates the use of methods that minimize transmitter loss and fish mortality and optimize healing of the incision. We evaluated the effects of three incision locations on transmitter loss, healing, survival, growth, and suture retention in juvenile Chinook salmon Oncorhynchus tshawytscha. The three incision locations were (1) on the linea alba (LA incision), (2) adjacent and parallel to the LA (muscle-cutting [MC] incision), and (3) extending from the LA towards the dorsum at a 45° angle, between the parallel lines of myomeres (muscle-sparing [MS] incision). A Juvenile Salmon Acoustic Telemetry System acoustic transmitter (0.44 g in air) and a passive integrated transponder tag (0.10 g in air) were implanted into each fish (total N = 936 fish). The fish were held at 12°C or 20°C and were examined weekly for 98 d. The progression of healing among incision locations and the variability in transmitter loss made it difficult to identify one incision location as the best choice. The LA incisions had a much smaller wound extent (area of visible subepidermal tissue) than MC and MS incisions during the first 28 d of the study. In both temperature treatments, apposition of incisions through day 14 was better for LA incisions than for MC and MS incisions. However, MC and MS incisions were less likely than LA incisions to reopen over time and thus were less likely to allow transmitter loss through the incision.

  9. Dielectric Relaxation of Hexadeutero Dimethylsulfoxide

    NASA Astrophysics Data System (ADS)

    Betting, H.; Stockhausen, M.

    1999-11-01

    The dielectric relaxation parameters of the title substance (DMSO-d6) in its pure liquid state are determined from meas-urements up to 72 GHz at 20°C in comparison to protonated DMSO. While the relaxation strengths do not differ, the relax-ation time of DMSO-d 6 is significantly longer (21.3 ps) than that of DMSO (19.5 ps).

  10. Relaxation in Physical Education Curricula.

    ERIC Educational Resources Information Center

    Coville, Claudia A.

    1979-01-01

    A theoretical framework for incorporating relaxation instruction in the physical education curriculum is presented based on the assumption that relaxation is a muscular-skeletal skill benefitting general motor skill acquisition. Theoretical principles, a definition of relaxation, and an analysis of stages of skill development are also used in the…

  11. Relaxation phenomena in disordered systems

    NASA Astrophysics Data System (ADS)

    Sciortino, F.; Tartaglia, P.

    1997-02-01

    In this article we discuss how the assumptions of self-similarity imposed on the distribution of independently relaxing modes, as well as on their amplitude and characteristic times, manifest in the global relaxation phenomena. We also review recent applications of such approach to the description of relaxation phenomena in microemulsions and molecular glasses.

  12. A Comparison of Relaxation Strategies.

    ERIC Educational Resources Information Center

    Matthews, Doris B.

    Some researchers argue that all relaxation techniques produce a single relaxation response while others support a specific-effects hypothesis which suggests that progressive relaxation affects the musculoskeletal system and that guided imagery affects cognitive changes. Autogenics is considered a technique which is both somatic and cognitive. This…

  13. Jael syndrome: removal of a knife blade impacted in the maxillofacial region under local anaesthesia

    PubMed Central

    Dominguete, Paulo Roberto; Matos, Bruno Figueiredo; Meyer, Tufi Neder; Oliveira, Lucinei Roberto

    2013-01-01

    The presence of retained foreign bodies in the maxillofacial region as a consequence of penetrating injuries from knives is poorly documented in the scientific literature. This manuscript reports the case of a 30-year-old Caucasian with a knife blade lodged in the maxillofacial skeleton. Following clinical and radiographic exams, it was determined that the object had penetrated through the left nostril and nasal septum, in the direction of the right maxillary sinus, and remained impacted without causing injury to important anatomical structures. After systemic assessment and determination of the exact location of the knife blade, the object was removed in an outpatient setting under local anaesthesia. This manuscript aims to report a rare case of a transfacial penetrating injury involving a knife blade that was removed in an outpatient setting while also discussing the proper conduct and treatment options for similar cases in the context of a brief literature review. PMID:23580680

  14. Acute necrosis after Gamma Knife surgery in vestibular schwannoma leading to multiple cranial nerve palsies.

    PubMed

    Kapitza, Sandra; Pangalu, Athina; Horstmann, Gerhard A; van Eck, Albert T; Regli, Luca; Tarnutzer, Alexander A

    2016-08-01

    We discuss a rare acute complication after Gamma Knife therapy (Elekta AB, Stockholm, Sweden) in a single patient. A 52-year-old woman presented with vertigo, facial weakness and hearing loss emerging 48hours following Gamma Knife radiosurgery for a right-sided vestibular schwannoma. Neurological examination 6days after symptom onset showed right-sided facial palsy, spontaneous left-beating nystagmus and pathologic head-impulse testing to the right. Pure-tone audiogram revealed right-sided sensorineural hearing loss. A diagnosis of acute vestibulocochlear and facial neuropathy was made. Brain MRI demonstrated focal contrast sparing within the schwannoma, likely related to acute radiation necrosis. Acute multiple cranial neuropathies of the cerebellopontine angle after Gamma Knife treatment should raise suspicion of acute tissue damage within the schwannoma and should result in urgent MRI. Treatment with steroids may be considered based on accompanying swelling and edema. PMID:26947104

  15. [Acupoint position and manipulation of needle knife treating shoulder bi syndrome].

    PubMed

    Zhao, Li; Guo, Changqing

    2016-03-01

    With Jianyu (LI 15), Jianliao (TE 14) and Jianzhen (SI 9) for instance, the three acupoints used to treat shoulder bi syndrome by needle knife, and through traceability and researching constant structure, the acupoint position, insertion trace, manipulation and clinical significance of needle knife medicine were discussed. Accurate position is one of the characteristics of acupoints selection of needle knife medicine. As for the acupoints selection method, the mean of body surface localization is always used. The phanerous or palpable bone processes, muscles and tendons are taken as positioning marks; pressing areas where appear sour, numb, or distensible and other sensations is considered as the principle of press positioning. So acupoints position method is the combination of observation and palpation. Different insertion methods can effectively relieve the accretive bursae synovialis, tendon, joint capsule and the compressed nerve, so that shoulder bi syndrome is relieved. PMID:27344840

  16. [Stereotactic Body Radiotherapy with CyberKnife®for Liver Metastases from Colorectal Cancer].

    PubMed

    Mihara, Koki; Kaihara, Masaki; Sunahori, Sayaka; Yamashiro, Naotsugu; Nishiya, Shin; Ito, Yasuhiro; Funakoshi, Kazuto; Egawa, Tomohisa; Tsukamoto, Nobuhiro; Nagashima, Atsushi

    2015-10-01

    For treatment of colorectal liver metastases, liver resection is recommended for resectable cases in the clinical guidelines for colorectal cancer. On the other hand, there are currently no data supporting the efficacy of radiation therapy as a topical treatment, and this treatment can therefore not presently be recommended. With CyberKnife®, it is possible to perform stereotactic radiation therapy using a linear accelerator with high accuracy, even for lesions in the trunk area such as liver metastases. Between December 2009 and September 2014 in our hospital, we performed radiation treatment using CyberKnife® for 14 cases with 22 colorectal liver metastases. As a result, we obtained response and local control rates of 76.2%and 81.0%, respectively. Moreover, no advanced adverse events were observed. Thus, we consider that CyberKnife® treatment for colorectal liver metastases is effective as a topical treatment, with low invasiveness and high safety. PMID:26489566

  17. Metal Fatigue Causing Cystoscope Rupture During Bladder Neck Incision

    PubMed Central

    Fernandez, Alfonso

    2011-01-01

    The modern cystoscope is the result of the advancement in technology in numerous areas and is an invaluable tool that allows the urologist to perform a number of diagnostic and therapeutic procedures. Although various degrees of endoscope failure have been widely reported, instrument breakage that leads to a foreign body has not. While performing a bladder neck stricture incision for a 72-year-old male patient with a previous radical prostatectomy for prostate cancer and a resulting bladder neck stricture, we documented a major 17-French cystoscope malfunction and a resulting foreign body that was retrieved from the bladder using a 22-French scope and alligator forceps. PMID:21985739

  18. Conjunctival inclusion cysts following small incision cataract surgery.

    PubMed

    Narayanappa, Shylaja; Dayananda, S; Dakshayini, M; Gangasagara, Suresh Babu; Prabhakaran, Venkatesh C

    2010-01-01

    The occurrence of acquired conjunctival inclusion cysts following various ophthalmic surgeries such as strabismus surgery, scleral buckling, pars plana vitrectomy, ptosis surgery and phacoemulsification has been reported. We report two cases of conjunctival inclusion cysts following manual Small Incision Cataract Surgery (SICS) in two male patients aged 65 and 67 years. The cysts originated from the scleral tunnel used for manual SICS. Both were treated by excision and confirmed histopathologically. No recurrence was noted at three months follow-up. To our knowledge, conjunctival inclusion cysts following SICS have not been reported previously. Careful reflection of conjunctiva during tunnel construction and posterior chamber intraocular lens implantation may prevent their occurrence. PMID:20689201

  19. Review of single incision laparoscopic surgery in colorectal surgery

    PubMed Central

    Madhoun, Nisreen; Keller, Deborah S; Haas, Eric M

    2015-01-01

    As surgical techniques continue to move towards less invasive techniques, single incision laparoscopic surgery (SILS), a hybrid between traditional multiport laparoscopy and natural orifice transluminal endoscopic surgery, was introduced to further the enhanced outcomes of multiport laparoscopy. The safety and feasibility of SILS for both benign and malignant colorectal disease has been proven. SILS provides the potential for improved cosmesis, postoperative pain, recovery time, and quality of life at the drawback of higher technical skill required. In this article, we review the history, describe the available technology and techniques, and evaluate the benefits and limitations of SILS for colorectal surgery in the published literature. PMID:26478673

  20. Wound construction in manual small incision cataract surgery

    PubMed Central

    Haldipurkar, S S; Shikari, Hasanain T; Gokhale, Vishwanath

    2009-01-01

    The basis of manual small incision cataract surgery is the tunnel construction for entry to the anterior chamber. The parameters important for the structural integrity of the tunnel are the self-sealing property of the tunnel, the location of the wound on the sclera with respect to the limbus, and the shape of the wound. Cataract surgery has gone beyond just being a means to get the lens out of the eye. Postoperative astigmatism plays an important role in the evaluation of final outcome of surgery. Astigmatic consideration, hence, forms an integral part of incisional considerations prior to surgery. PMID:19075401

  1. Gamma knife surgery for epilepsy related to hypothalamic hamartomas.

    PubMed

    Régis, Jean; Scavarda, Didier; Tamura, Manabu; Villeneuve, Nathalie; Bartolomei, Fabrice; Brue, Thierry; Morange, Isabelle; Dafonseca, David; Chauvel, Patrick

    2007-06-01

    Numerous neurosurgical approaches are available for children presenting with hypothalamic hamartomas (HHs) associated with severe epilepsy. A concern regarding the impairment of short-term memory after resective surgery is promoting the exploration of less invasive alternatives like radiosurgery. Gamma knife radiosurgery (GKS) can lead to a real reversal of the epileptic encephalopathy. Three years after radiosurgery, 60% of the children have an excellent result with complete seizure cessation in 40% and rare nondisabling seizures in 20%, often in association with dramatic behavioral and cognitive improvement. No permanent neurologic complications have thus far been reported. Rare transient cases of poikilothermia have been observed. GKS is clearly the safer approach for these difficult patients. Young patients with severe epilepsy and neurocognitive comorbidity must be treated by using a curative approach as early as possible. Topological type (according to our original classification) is the major feature for selection of the best treatment strategy. Type I HH deeply embedded in the hypothalamus is treated safely and efficiently by GKS. Type II HH can be resected by either endoscopic or transcallosal approaches or treated by GKS depending on the parent's choice and severity of epilepsy. In small type III HH, GKS is the safer procedure because of the very close relationship to the fornix and mammillary bodies. Types V (rarely epileptic) and IV are frequently operable by disconnection. Very large type VI (or mixed type) with a large component above the floor of the third ventricle must be disconnected, and then the upper remnant is best treated by GKS using a staged technique. Overall, when the lesion is sufficiently small, GKS offers a rate of seizure control comparable to microsurgery but with much lower risk. The disadvantage of radiosurgery is its delayed action. Longer follow-up is mandatory for a reliable evaluation of the role of GKS. PMID:17544950

  2. Salvage Gamma Knife Stereotactic Radiosurgery for Surgically Refractory Trigeminal Neuralgia

    SciTech Connect

    Little, Andrew S.; Shetter, Andrew G. Shetter, Mary E.; Kakarla, Udaya K.; Rogers, C. Leland

    2009-06-01

    Purpose: To evaluate the clinical outcome of patients with surgically refractory trigeminal neuralgia (TN) treated with rescue gamma knife radiosurgery (GKRS). Methods and Materials: Seventy-nine patients with typical TN received salvage GKRS between 1997 and 2002 at the Barrow Neurological Institute (BNI). All patients had recurrent pain following at least one prior surgical intervention. Prior surgical interventions included percutaneous destructive procedures, microvascular decompression (MVD), or GKRS. Thirty-one (39%) had undergone at least two prior procedures. The most common salvage dose was 80 Gy, although 40-50 Gy was typical in patients who had received prior radiosurgery. Pain outcome was assessed using the BNI Pain Intensity Score, and quality of life was assessed using the Brief Pain Inventory. Results: Median follow-up after salvage GKRS was 5.3 years. Actuarial analysis demonstrated that at 5 years, 20% of patients were pain-free and 50% had pain relief. Pain recurred in patients who had an initial response to GKRS at a median of 1.1 years. Twenty-eight (41%) required a subsequent surgical procedure for recurrence. A multivariate Cox proportional hazards model suggested that the strongest predictor of GKRS failure was a history of prior MVD (p=0.029). There were no instances of serious morbidity or mortality. Ten percent of patients developed worsening facial numbness and 8% described their numbness as 'very bothersome.' Conclusions: GKRS salvage for refractory TN is well tolerated and results in long-term pain relief in approximately half the patients treated. Clinicians may reconsider using GKRS to salvage patients who have failed prior MVD.

  3. Adaptive hypofractionated gamma knife radiosurgery for a large brainstem metastasis

    PubMed Central

    Sinclair, Georges; Bartek, Jiri; Martin, Heather; Barsoum, Pierre; Dodoo, Ernest

    2016-01-01

    Background: To demonstrate how adaptive hypofractionated radiosurgery by gamma knife (GK) can be successfully utilized to treat a large brainstem metastasis - a novel approach to a challenging clinical situation. Case Description: A 42-year-old woman, diagnosed with metastatic nonsmall cell lung cancer in July 2011, initially treated with chemotherapy and tyrosine kinase inhibitors, developed multiple brain metastases March 2013, with subsequent whole brain radiotherapy, after which a magnetic resonance imaging (MRI) showed a significant volume regression of all brain metastases. A follow-up MRI in October 2013 revealed a growing brainstem lesion of 26 mm. Linear accelerator-based radiotherapy and microsurgery were judged contraindicated, why the decision was made to treat the patient with three separate radiosurgical sessions during the course of 1 week, with an 18% tumor volume reduction demonstrated after the last treatment. Follow-up MRI 2.5 months after her radiosurgical treatment showed a tumor volume reduction of 67% compared to the 1st day of treatment. Later on, the patient developed a radiation-induced perilesional edema although without major clinical implications. An MRI at 12 months and 18-fluoro-deoxyglucose positron emission tomography of the brain at 13 months showed decreased edema with no signs of tumor recurrence. Despite disease progression during the last months of her life, the patient's condition remained overall acceptable. Conclusion: GK-based stereotactic adaptive hypofractionation proved to be effective to achieve tumor control while limiting local adverse reactions. This surgical modality should be considered when managing larger brain lesions in critical areas. PMID:26958430

  4. Gamma Knife Radiosurgery for the Treatment of Cystic Cerebral Metastases

    SciTech Connect

    Ebinu, Julius O.; Lwu, Shelly; Monsalves, Eric; Arayee, Mandana; Chung, Caroline; Laperriere, Normand J.; Kulkarni, Abhaya V.; Goetz, Pablo; Zadeh, Gelareh

    2013-03-01

    Purpose: To assess the role of Gamma Knife radiosurgery (GKRS) in the treatment of nonsurgical cystic brain metastasis, and to determine predictors of response to GKRS. Methods: We reviewed a prospectively maintained database of brain metastases patients treated at our institution between 2006 and 2010. All lesions with a cystic component were identified, and volumetric analysis was done to measure percentage of cystic volume on day of treatment and consecutive follow-up MRI scans. Clinical, radiologic, and dosimetry parameters were reviewed to establish the overall response of cystic metastases to GKRS as well as identify potential predictive factors of response. Results: A total of 111 lesions in 73 patients were analyzed; 57% of lesions received prior whole-brain radiation therapy (WBRT). Lung carcinoma was the primary cancer in 51% of patients, 10% breast, 10% colorectal, 4% melanoma, and 26% other. Fifty-seven percent of the patients were recursive partitioning analysis class 1, the remainder class 2. Mean target volume was 3.3 mL (range, 0.1-23 mL). Median prescription dose was 21 Gy (range, 15-24 Gy). Local control rates were 91%, 63%, and 37% at 6, 12, and 18 months, respectively. Local control was improved in lung primary and worse in patients with prior WBRT (univariate). Only lung primary predicted local control in multivariate analysis, whereas age and tumor volume did not. Lesions with a large cystic component did not show a poorer response compared with those with a small cystic component. Conclusions: This study supports the use of GKRS in the management of nonsurgical cystic metastases, despite a traditionally perceived poorer response. Our local control rates are comparable to a matched cohort of noncystic brain metastases, and therefore the presence of a large cystic component should not deter the use of GKRS. Predictors of response included tumor subtype. Prior WBRT decreased effectiveness of SRS for local control rates.

  5. Clinical outcomes following salvage Gamma Knife radiosurgery for recurrent glioblastoma

    PubMed Central

    Larson, Erik W; Peterson, Halloran E; Lamoreaux, Wayne T; MacKay, Alexander R; Fairbanks, Robert K; Call, Jason A; Carlson, Jonathan D; Ling, Benjamin C; Demakas, John J; Cooke, Barton S; Lee, Christopher M

    2014-01-01

    Glioblastoma multiforme (GBM) is the most common malignant primary brain tumor with a survival prognosis of 14-16 mo for the highest functioning patients. Despite aggressive, multimodal upfront therapies, the majority of GBMs will recur in approximately six months. Salvage therapy options for recurrent GBM (rGBM) are an area of intense research. This study compares recent survival and quality of life outcomes following Gamma Knife radiosurgery (GKRS) salvage therapy. Following a PubMed search for studies using GKRS as salvage therapy for malignant gliomas, nine articles from 2005 to July 2013 were identified which evaluated rGBM treatment. In this review, we compare Overall survival following diagnosis, Overall survival following salvage treatment, Progression-free survival, Time to recurrence, Local tumor control, and adverse radiation effects. This report discusses results for rGBM patient populations alone, not for mixed populations with other tumor histology grades. All nine studies reported median overall survival rates (from diagnosis, range: 16.7-33.2 mo; from salvage, range: 9-17.9 mo). Three studies identified median progression-free survival (range: 4.6-14.9 mo). Two showed median time to recurrence of GBM. Two discussed local tumor control. Six studies reported adverse radiation effects (range: 0%-46% of patients). The greatest survival advantages were seen in patients who received GKRS salvage along with other treatments, like resection or bevacizumab, suggesting that appropriately tailored multimodal therapy should be considered with each rGBM patient. However, there needs to be a randomized clinical trial to test GKRS for rGBM before the possibility of selection bias can be dismissed. PMID:24829861

  6. The guillotine knife: a novel tool for safe endoscopic cutting of intracranial membranes.

    PubMed

    El Damaty, Ahmed; Manwaring, Jotham C; Schroeder, Henry W S

    2014-09-01

    This article describes a new endoscopic cutting tool that acts like a guillotine. It enables safe cutting of membranes overlying neurovascular structures because the footplate protects these structures from inadvertent injury. The footplate is introduced under the membrane, elevating it slightly, and then the membrane is cut while pushing the blade down into the footplate. The guillotine knife has been used in various endoscopic procedures such as septostomies, arachnoid cyst fenestrations, colloid cysts resections, and fenestrations of other intraventricular membranes. The authors think that the guillotine knife is a useful addition to the neuroendoscopic armamentarium. PMID:24926646

  7. Transurethral incision of prostate compared with transurethral resection of prostate in 132 matching cases.

    PubMed

    Orandi, A

    1987-10-01

    In a prospective project during a 2-year period 132 patients with bladder outlet obstruction who were candidates for transurethral incision of the prostate were managed alternately by transurethral incision and transurethral resection of the prostate. Both operations were compared in matched patients. The results and complications favored transurethral incision, although there was no statistical significance except for the high incidence of bladder neck contracture after transurethral resection (p equals 0.028). PMID:2443728

  8. Correlation between Corneal Endothelial Cell Loss and Location of Phacoemulsification Incision

    PubMed Central

    Gharaee, Hamid; Kargozar, Abbas; Daneshvar-Kakhki, Ramin; Sharepour, Maria; Hassanzadeh, Samira

    2011-01-01

    Purpose To assess the relationship between corneal endothelial cell loss after phacoemulsification and the location of the clear corneal incision. Methods A total of 92 patients (92 eyes) with senile cataracts who met the study criteria were included in this cross sectional study and underwent phacoemulsification. The incision site was determined based on the steep corneal meridian according to preoperative keratometry. Endothelial cell density was measured using specular microscopy in the center and 3 mm from the center of the cornea in the meridian of the incisions (temporal, superior, and superotemporal). Phacoemulsification was performed by a single surgeon using the phaco chop technique through a 3.2 mm clear cornea incision. Endothelial cell loss (ECL) was evaluated 1 week, and 1 and 3 months postoperatively. Results At all time points during follow-up, ECL was comparable among the 3 incision sites, both in the central cornea and in the meridian of the incision (P > 0.05 for all comparisons). However, 3 months postoperatively, mean central ECL with superior incisions and mean sectoral ECL with temporal incisions were slightly higher. Superotemporal incisions entailed slightly less ECL than the other 2 groups. Overall, one month after surgery, mean central ECL was 10.8% and mean ECL in the sector of the incisions was 14.0%. Axial length and effective phaco time (EFT) were independent predictors of postoperative central ECL (P values 0.005 and < 0.0001, respectively). Conclusion A superotemporal phacoemulsification incision may entail less ECL as compared to other incisions (although not significantly different). The amount of central ECL may be less marked in patients with longer axial lengths and with procedures utilizing less EFT. PMID:22454701

  9. Single incision laparoscopic liver resection (SILL) – a systematic review

    PubMed Central

    Benzing, Christian; Krenzien, Felix; Atanasov, Georgi; Seehofer, Daniel; Sucher, Robert; Zorron, Ricardo; Pratschke, Johann; Schmelzle, Moritz

    2015-01-01

    Background: Today, minimally invasive liver resections for both benign and malignant tumors are routinely performed. Recently, some authors have described single incision laparoscopic liver resection (SILL) procedures. Since SILL is a relatively young branch of laparoscopy, we performed a systematic review of the current literature to collect data on feasibility, perioperative results and oncological outcome. Methods: A literature research was performed on Medline for all studies that met the eligibility criteria. Titles and abstracts were screened by two authors independently. A study was included for review if consensus was obtained by discussion between the authors on the basis of predefined inclusion criteria. A thorough quality assessment of all included studies was performed. Data were analyzed and tabulated according to predefined outcome measures. Synthesis of the results was achieved by narrative review. Results: A total of 15 eligible studies were identified among which there was one prospective cohort study and one randomized controlled trial comparing SILL to multi incision laparoscopic liver resection (MILL). The rest were retrospective case series with a maximum of 24 patients. All studies demonstrated convincing results with regards to feasibility, morbidity and mortality. The rate of wound complications and incisional hernia was low. The cosmetic results were good. Conclusions: This is the first systematic review on SILL including prospective trials. The results of the existing studies reporting on SILL are favorable. However, a large body of scientific evidence on the field of SILL is missing, further randomized controlled studies are urgently needed. PMID:26734538

  10. Single-incision laparoscopic surgery for colorectal cancer

    PubMed Central

    Hirano, Yasumitsu; Hattori, Masakazu; Douden, Kenji; Ishiyama, Yasuhiro; Hashizume, Yasuo

    2016-01-01

    AIM: To determine the effect of single-incision laparoscopic colectomy (SILC) for colorectal cancer on short-term clinical and oncological outcomes by comparison with multiport conventional laparoscopic colectomy (CLC). METHODS: A systematic review was performed using MEDLINE for the time period of 2008 to December 2014 to retrieve all relevant literature. The search terms were “laparoscopy”, “single incision”, “single port”, “single site”, “SILS”, “LESS” and “colorectal cancer”. Publications were included if they were randomized controlled trials, case-matched controlled studies, or comparative studies, in which patients underwent single-incision (SILS or LESS) laparoscopic colorectal surgery. Studies were excluded if they were non-comparative, or not including surgery involving the colon or rectum. A total of 15 studies with 589 patients who underwent SILC for colorectal cancer were selected. RESULTS: No significant differences between the groups were noted in terms of mortality or morbidity. The benefit of the SILC approach included reduction in conversion rate to laparotomy, but there were no significant differences in other short-term clinical outcomes between the groups. Satisfactory oncological surgical quality was also demonstrated for SILC for the treatment of colorectal cancer with a similar average lymph node harvest and proximal and distal resection margin length as multiport CLC. CONCLUSION: SILC can be performed safely with similar short-term clinical and oncological outcomes as multiport CLC. PMID:26843918

  11. Sutureless cataract incision closure using laser-activated tissue glues

    NASA Astrophysics Data System (ADS)

    Eaton, Alexander M.; Bass, Lawrence S.; Libutti, Steven K.; Schubert, Herman D.; Treat, Michael R.

    1991-06-01

    With the advent of phacoemulsification and foldable intraocular lenses, there is renewed interest in sutureless cataract wound. We report the use of laser activated tissue glues for the closure of scleral tunnel cataract incisions. Two glue mixtures were tested in enucleated porcine eyes. Glue A was composed of hyaluronic acid, human albumin, and indocyanine green dye. Glue B contained hyaluronic acid, chondroitin sulfate, human albumin, and indocyanine green dye. A Spectra Physics diode laser (808 nm) with a power density of 7-1 1 watts/cm2 was used for glue activation. Wound bursting pressures, as determined by the presence of fluid at the wound margin, was significantly higher with both glue combinations than without the glue (Pincisions.

  12. Rapid incision of the Colorado River in Glen Canyon - insights from channel profiles, local incision rates, and modeling of lithologic controls

    USGS Publications Warehouse

    Cook, K.L.; Whipple, K.X.; Heimsath, A.M.; Hanks, T.C.

    2009-01-01

    The Colorado River system in southern Utah and northern Arizona is continuing to adjust to the baselevel fall responsible for the carving of the Grand Canyon. Estimates of bedrock incision rates in this area vary widely, hinting at the transient state of the Colorado and its tributaries. In conjunction with these data, we use longitudinal profiles of the Colorado and tributaries between Marble Canyon and Cataract Canyon to investigate the incision history of the Colorado in this region. We find that almost all of the tributaries in this region steepen as they enter the Colorado River. The consistent presence of oversteepened reaches with similar elevation drops in the lower section of these channels, and their coincidence within a corridor of high local relief along the Colorado, suggest that the tributaries are steepening in response to an episode of increased incision rate on the mainstem. This analysis makes testable predictions about spatial variations in incision rates; these predictions are consistent with existing rate estimates and can be used to guide further studies. We also present cosmogenic nuclide data from the Henry Mountains of southern Utah. We measured in situ 10Be concentrations on four gravel-covered strath surfaces elevated from 1 m to 110 m above Trachyte Creek. The surfaces yield exposure ages that range from approximately 2??5 ka to 267 ka and suggest incision rates that vary between 350 and 600 m/my. These incision rates are similar to other rates determined within the high-relief corridor. Available data thus support the interpretation that tributaries of the Colorado River upstream of the Grand Canyon are responding to a recent pulse of rapid incision on the Colorado. Numerical modeling of detachment-limited bedrock incision suggests that this incision pulse is likely related to the upstream-dipping lithologic boundary at the northern edge of the Kaibab upwarp. ?? 2009 John Wiley & Sons, Ltd.

  13. An episode of rapid bedrock channel incision during the last glacial cycle, measured with 10Be

    USGS Publications Warehouse

    Reusser, L.; Bierman, P.; Pavich, M.; Larsen, J.; Finkel, R.

    2006-01-01

    We use 10Be to infer when, how fast, and why the Susquehanna River incised through bedrock along the U.S. Atlantic seaboard, one of the world's most prominent and ancient passive margins. Although the rate at which large rivers incise rock is a fundamental control on the development of landscapes, relatively few studies have directly measured how quickly such incision occurs either in tectonically active environments or along passive margins. Exposure ages of fluvially carve d, bedrock strath terraces, preserved along the lower Susquehanna River, demonstrate that even along a passive margin, large rivers are capable of incising through rock for short periods of time at rates approaching those recorded in tectonically active regions, such as the Himalayas. Over eighty samples, collected along and between three prominent levels of strath terraces within Holtwood Gorge, indicate that the Susquehanna River incised more than 10 meters into the Appalachian Piedmont during the last glacial cycle. Beginning ???36 ka, incision rates increased dramatically, and remained elevated until ???14 ka. The northern half of the Susquehanna basin was glaciated during the late Wisconsinan; however, similar rates and timing of incision occurred in the unglaciated Potomac River basin immediately to the south. The concurrence of incision periods on both rivers suggests that glaciation and associated meltwater were not the primary drivers of incision. Instead, it appears that changing climatic conditions during the late Pleistocene promoted an increase in the frequency and magnitude of flood events capable of exceeding thresholds for rock detachment and bedrock erosion, thus enabling a short-lived episode of rapid incision into rock. Although this study has constraine d the timing and rate of bedrock incision along the largest river draining the Atlantic passive margin, the dates alone cannot explain fully why, or by what processes, this incision occurred. However, cosmogenic dating offers

  14. Paraglacial fluvial bedrock incision in postglacial landscapes: the NW Scottish Highlands

    NASA Astrophysics Data System (ADS)

    Whitbread, Katie; Jansen, John; Bishop, Paul; Fabel, Derek

    2010-05-01

    Glacial landscape forms are inherited by rivers following deglaciation. Hillslopes and valley floors configured by glacial erosion control the distribution of bedrock channels and potential sites for fluvial incision. The importance of 'stream power' parameters, channel slope and drainage area (discharge), in controlling the rate of incision is widely accepted, but the rate, timing and mechanisms of incision have yet to be quantified in these settings. The dual controls of glacially conditioned bedrock slopes and sediment supply set two of the key boundary conditions for temporally and spatially dynamic fluvial bedrock incision. Measurement of incision rates in these settings is key to understanding the influence of controls on fluvial erosion, and the role of the process in long-term evolution of deglaciated landscapes. In tectonically-passive, hard-rock terrains, such as the Scottish Highlands, incisional fluvial features such as bedrock channels, gorges and waterfalls are common on glacially carved valley steps. Here we report preliminary data on fluvial incision rates measured with cosmogenic 10Be. Our results confirm a postglacial age of bedrock straths in the NW Scottish Highlands and indicate a vertical incision rate of 0.3 mm/yr into resistant quartzites. Further work will explore erosion mechanisms and rates of incision across the Scottish Highlands, and assess controls on fluvial incision, including the potential role of paraglacial sediment.

  15. Safety of cesarean delivery through placental incision in patients with anterior placenta previa

    PubMed Central

    Hong, Deok-Ho; Kim, Eugene; Kyeong, Kyu-Sang; Hong, Seung Hwa

    2016-01-01

    Objective To demonstrate the safety of fetal delivery through placental incision in a placenta previa pregnancy. Methods We examined the medical records of 80 women with singleton pregnancy diagnosed with placenta previa who underwent cesarean section between May 2010 and May 2015 at the Department of Obstetrics and Gynecology, Chungbuk National University Hospital. Among the women with placenta previa, those who did not have the placenta in the uterine incision site gave birth via conventional uterine incision, while those with anterior placenta previa or had placenta attached to the uterine incision site gave birth via uterine incision plus placental incision. We compared the postoperative hemoglobin level and duration of hospital stay for the mother and newborn of the two groups. Results There was no difference between the placental incision group and non-incision group in terms of preoperative and postoperative hemoglobin change, the amount of blood transfusions required by the mother, newborns with 1-min or 5-min Apgar scores below 7 points or showing signs of acidosis on umbilical cord blood gas analysis result of pH below 7.20. Moreover, neonatal hemoglobin levels did not differ between the two groups. Conclusion Fetal delivery through placental incision during cesarean section for placenta previa pregnancy does not negatively influence the prognosis of the mother or the newborn, and therefore, is considered a safe surgical technique. PMID:27004200

  16. Comparison of fibrin glue and suture in the healing of teat incisions in lactating goats.

    PubMed

    Alan, M; Yener, Z; Tasal, I; Bakir, B

    2008-05-01

    The aims of this study were to investigate whether fibrin glue can be used to close experimentally induced incisions of the teat (mammary papillae) in lactating goats and to compare the healing of the glued with the sutured incisions. Four clinically healthy lactating dairy goats, namely 8 mammary papillae were used. After surgical preparation of the papillae, a 3.5 cm long incision of each papilla was made through skin, muscular layer and mucosa into the papillary sinus. The wounds in the right papillae in all goats were closed with U-shaped uninterrupted 00 chromic catgut sutures. The wounds in the left papillae in all goats were closed, using fibrin glue. One incision was seen to be dehisced and fistulous one day after in fibrin glued teats. The animals were slaughtered 8 days after surgical manipulation. The mammary papillae were removed and examined in the viewpoint on gross and microscopic findings. The healing of wounds was slower and feeble in glued mammary papillary incisions, however faster and stronger in sutured incisions on day 8 after operations. But, available outcomes like less tissue thickness and positive cosmetic results could be obtained byfibrin glue used on mammary papillary incisions, which are very important for teats to be milked by hand and milking machine. Results suggest that it is advisable to use only one or two simple interrupted sutures in teat incisions glued with fibrin to prevent the dehiscence but with a more reliable healing than the sutured incisions. PMID:18547021

  17. MAGAT gel and EBT2 film-based dosimetry for evaluating source plugging-based treatment plan in Gamma Knife stereotactic radiosurgery.

    PubMed

    Natanasabapathi, Gopishankar; Subbiah, Vivekanandhan; Kale, Shashank Sharad; Rath, Goura Kishor; Senthilkumaran, S; Thulkar, Sanjay; Subramani, Vellaiyan; Laviraj, M A; Bisht, Raj Kishor; Mahapatra, A K

    2012-01-01

    This work illustrates a procedure to assess the overall accuracy associated with Gamma Knife treatment planning using plugging. The main role of source plugging or blocking is to create dose falloff in the junction between a target and a critical structure. We report the use of MAGAT gel dosimeter for verification of an experimental treatment plan based on plugging. The polymer gel contained in a head-sized glass container simulated all major aspects of the treatment process of Gamma Knife radiosurgery. The 3D dose distribution recorded in the gel dosimeter was read using a 1.5T MRI scanner. Scanning protocol was: CPMG pulse sequence with 8 equidistant echoes, TR = 7 s, echo step = 14 ms, pixel size = 0.5mm × 0.5mm, and slice thickness of 2 mm. Using a calibration relationship between absorbed dose and spin-spin relaxation rate (R2), we converted R2 images to dose images. Volumetric dose comparison between treatment planning system (TPS) and gel measurement was accomplished using an in-house MATLAB-based program. The isodose overlay of the measured and computed dose distribution on axial planes was in close agreement. Gamma index analysis of 3D data showed more than 94% voxel pass rate for different tolerance criteria of 3%/2 mm, 3%/1 mm and 2%/2 mm. Film dosimetry with GAFCHROMIC EBT 2 film was also performed to compare the results with the calculated TPS dose. Gamma index analysis of film measurement for the same tolerance criteria used for gel measurement evaluation showed more than 95% voxel pass rate. Verification of gamma plan calculated dose on account of shield is not part of acceptance testing of Leksell Gamma Knife (LGK). Through this study we accomplished a volumetric comparison of dose distributions measured with a polymer gel dosimeter and Leksell GammaPlan (LGP) calculations for plans using plugging. We propose gel dosimeter as a quality assurance (QA) tool for verification of plug-based planning. PMID:23149780

  18. Development of an air-knife system for highly reproducible fabrication of polydimethylsiloxane microstencils

    NASA Astrophysics Data System (ADS)

    Choi, Jin Ho; Kim, Gyu Man

    2015-08-01

    In this study, an air-knife system was developed for the automated fabrication of polymer microstencils with microscale perforated patterns. Blowing compressed N2 gas through the air knife provided a uniform laminar gas flow of high intensity suitable for perforating holes in the stencil. The polydimethylsiloxane (PDMS) stencil was replicated from a master mold prepared by photolithography. When the prepolymer of PDMS was spin-coated onto the master mold, a thin layer of the prepolymer remained on top of the master's structure and consequently prevented the formation of the perforated patterns. This residual layer was easily removed by the presented air knife. The air-knife system controlled the flow rate of N2 gas and the conveying speed of the master mold; therefore, the system possessed high reproducibility compared to manual gas blowing. Its use reduced the fabrication time for perforated biocompatible polymer microstencils, allowing for their mass production via an automated system. The validity of this suggested method was proven through experiments and was evaluated by application in various fields.

  19. Stereotactic ablative radiotherapy with CyberKnife for advanced thymic carcinoma: a case report

    PubMed Central

    Fan, C.Y.; Huang, W.Y.; Jen, Y.M.; Lin, M.J.; Lin, K.T.

    2015-01-01

    Thymic carcinoma is a rare but lethal mediastinal cancer. The optimal treatment for advanced thymic carcinoma is not yet established. This report is the first known of stereotactic ablative radiotherapy (sabr) with CyberKnife (Accuray, Sunnyvale, CA, U.S.A.) as definitive therapy for thymic carcinoma. The patient, a 70-year-old woman with thymic carcinoma, invasion into neighboring organs, and pleural metastases—underwent CyberKnife sabr at 40 Gy in 5 fractions for two lesions, one in the thymus and one in the right paraspinal pleura. After 61 months of observation, a partial response was observed in the irradiated fields. However, disease progression in the non-irradiated pleura was noted. The patient underwent salvage CyberKnife sabr for the four initially nonirradiated pleural lesions. Computed tomography images obtained 10 months after the salvage therapy revealed a partial response. The patient is living, with progression-free irradiated lesions and no radiation-related toxicity. CyberKnife sabr is feasible for patients who are unable to undergo either surgery or conventionally fractionated radiation therapy. PMID:26628883

  20. Dose De-Escalation With Gamma Knife Radiosurgery in the Treatment of Choroidal Melanoma

    SciTech Connect

    Schirmer, Clemens M.; Chan, Michael; Mignano, John; Duker, Jay; Melhus, Christopher S.; Williams, Lloyd B.; Wu, Julian K.; Yao, Kevin C.

    2009-09-01

    Purpose: Single-fraction targeted radiation therapy delivered by the Leksell Gamma Knife system is a minimally invasive treatment option for choroidal melanoma that has been used as an alternative to enucleation, proton beam therapy, or brachytherapy. Previously reported Gamma Knife series involved the treatment of choroidal melanomas with a dose of 40 to 50 Gy at the tumor margin. We report our institutional experience using a significantly lower dose. Methods and Materials: Fourteen patients with choroidal melanoma were treated with the Leksell Gamma Knife at our institution over a 7-year period. The treatment and clinical data were analyzed in a retrospective fashion after a mean follow-up of 32.2 months. Results: The mean dose to the tumor margin was 22.2 {+-} 2.4 Gy (range, 20- 25 Gy). Mean treated tumor volume was 1.1 {+-} 1.2 cc. Local control was achieved in 13 cases (93%). In 1 patient both intraocular spread and distant metastatic disease developed after treatment. Visual function of the affected eye was preserved in 5 patients (36%) at latest follow-up, in 9 patients (64%) visual loss ensued. Mild to moderate radiation toxicity developed in 8 patients. Conclusions: Choroidal melanoma can be safely and effectively treated using Leksell Gamma Knife stereotactic radiosurgery with a marginal dose of less than 25 Gy.

  1. 18. DETAIL OF COMBINATION HANDWASH SINK/KNIFE STERILIZER ON SPLITTERS' PLATFORM; ...

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

    18. DETAIL OF COMBINATION HANDWASH SINK/KNIFE STERILIZER ON SPLITTERS' PLATFORM; KNIVES AND CLEAVERS WERE CLEANED FREQUENTLY BY DIPPING THEM INTO STEAM-HEATED WATER IN THE RECTANGULAR TANK; NOTE FOOT-OPERATED FAUCETS - Rath Packing Company, Beef Killing Building, Sycamore Street between Elm & Eighteenth Streets, Waterloo, Black Hawk County, IA

  2. Chief Dull Knife Community Is Strengthening the Northern Cheyenne Language and Culture.

    ERIC Educational Resources Information Center

    Littlebear, Richard E.

    2003-01-01

    Language revitalization programs should focus on whether they want to teach the language, teach about the language, teach with the language, or teach the language for academic credit. A program at Chief Dull Knife College (Montana) teaches the Cheyenne language using the Total Physical Response method, which replicates the manner in which first…

  3. CT-Guided Fiducial Placement for CyberKnife Stereotactic Radiosurgery: An Initial Experience

    SciTech Connect

    Sotiropoulou, Evangelia; Stathochristopoulou, Irene; Stathopoulos, Konstantinos; Verigos, Kosmas; Salvaras, Nikolaos; Thanos, Loukas

    2010-06-15

    CyberKnife frameless image-guided radiosurgery has become a widely used system for parenchymal extracranial lesions. Gold fiducials are required for the planning and aiming of CyberKnife therapy. We report our initial experience and describe the technique of positioning tumor markers, under CT guidance. We conducted a retrospective review of 105 patients who were referred for CyberKnife stereotactic radiosurgery at Iatropolis CyberKnife Center in Athens. All patients underwent percutaneous fiducial placement via CT guidance. At the desired location, the 18-G needle was advanced into or near the tumor. Data collected included number and locations of fiducials placed and complications experienced to date. One hundred five patients underwent fiducial placement under CT guidance and a total number of 319 gold seeds were implanted. We experienced one episode of pneumothorax that required drainage, one mild pneumothorax, and three episodes of perifocal pulmonary hemorrhage. In conclusion, fiducial implantation under CT guidance appears to be a safe and efficient procedure, as long as it is performed by an experienced interventional radiologist.

  4. "Liquid Knife" to Fabricate Patterning Single-Crystalline Perovskite Microplates toward High-Performance Laser Arrays.

    PubMed

    Feng, Jiangang; Yan, Xiaoxu; Zhang, Yifan; Wang, Xuedong; Wu, Yuchen; Su, Bin; Fu, Hongbin; Jiang, Lei

    2016-05-01

    A facile and effective "liquid knife" is created by controlling the dewetting process of the liquid precursor, yielding patterning single-crystalline perovskite microplates with uniform size, precise positioning, high quality, and low lasing thresholds. The sizes and location of single-crystalline perovskite are controllable, leading to mode-tunable lasing emission and patterned lasers. PMID:27000628

  5. Quantitative phase tomography by using x-ray microscope with Foucault knife-edge scanning filter

    NASA Astrophysics Data System (ADS)

    Watanabe, Norio; Tsuburaya, Yuji; Shimada, Akihiro; Aoki, Sadao

    2016-01-01

    Quantitative phase tomography was evaluated by using a differential phase microscope with a Foucault knife-edge scanning filter. A 3D x-ray phase image of polystyrene beads was obtained at 5.4 keV. The reconstructed refractive index was fairly good agreement with the Henke's tabulated data.

  6. Implementation of a quantitative Foucault knife-edge method by means of isophotometry

    NASA Astrophysics Data System (ADS)

    Zhevlakov, A. P.; Zatsepina, M. E.; Kirillovskii, V. K.

    2014-06-01

    Detailed description of stages of computer processing of the shadowgrams during implementation of a modern quantitative Foucault knife-edge method is presented. The map of wave-front aberrations introduced by errors of an optical surface or a system, along with the results of calculation of the set of required characteristics of image quality, are shown.

  7. The Effects of Swedish Knife Model on Students' Understanding of the Digestive System

    ERIC Educational Resources Information Center

    Cerrah Ozsevgec, Lale; Artun, Huseyin; Unal, Melike

    2012-01-01

    This study was designed to examine the effect of Swedish Knife Model on students' understanding of digestive system. A simple experimental design (pretest-treatment-posttest) was used in the study and internal comparison of the results of the one group was made. The sample consisted of 40 7th grade Turkish students whose ages range from 13 to 15.…

  8. Whole-procedure clinical accuracy of Gamma Knife treatments of large lesions

    SciTech Connect

    Ma Lijun; Chuang, Cynthia; Descovich, Martina; Petti, Paula; Smith, Vernon; Verhey, Lynn

    2008-11-15

    The mechanical accuracy of Gamma Knife radiosurgery based on single-isocenter measurement has been established to within 0.3 mm. However, the full delivery accuracy for Gamma Knife treatments of large lesions has only been estimated via the quadrature-sum analysis. In this study, the authors directly measured the whole-procedure accuracy for Gamma Knife treatments of large lesions to examine the validity of such estimation. The measurements were conducted on a head-phantom simulating the whole treatment procedure that included frame placement, computed tomography imaging, treatment planning, and treatment delivery. The results of the measurements were compared with the dose calculations from the treatment planning system. Average agreements of 0.1-1.6 mm for the isodose lines ranging from 25% to 90% of the maximum dose were found despite potentially large contributing uncertainties such as 3-mm imaging resolution, 2-mm dose grid size, 1-mm frame registration, multi-isocenter deliveries, etc. The results of our measurements were found to be significantly smaller (>50%) than the calculated value based on the quadrature-sum analysis. In conclusion, Gamma Knife treatments of large lesions can be delivered much more accurately than predicted from the quadrature-sum analysis of major sources of uncertainties from each step of the delivery chain.

  9. Gentlemen (and ladies), choose your weapons: Gamma knife vs. linear accelerator radiosurgery.

    PubMed

    Stieber, Volker W; Bourland, J Daniel; Tome, Wolfgang A; Mehta, Minesh P

    2003-04-01

    This article compares and contrasts Gamma Knife radiosurgery with linear accelerator-based radiosurgery; where appropriate, Cyberknife technology is discussed. Topics covered are: positioning of the head (invasive versus non-invasive positioning systems); collimator construction; beam properties; beam arrangements; treatment planning; and issues regarding manpower (including a discussion of patient repositioning during treatment), machine availability, and financial considerations. PMID:12680787

  10. Endoscopic Submucosal Dissection Using a Novel Versatile Knife: An Animal Feasibility Study (with Video)

    PubMed Central

    Kwon, Chang-Il; Kim, Gwangil; Kim, Won Hee; Ko, Kwang Hyun; Hong, Sung Pyo; Jeong, Seok; Lee, Don Haeng

    2014-01-01

    Background/Aims In order to reduce the procedure time and the number of accessory changes during endoscopic submucosal dissection (ESD), we developed a novel versatile knife, which has the combined advantages of several conventional knives. The aim of this study was to compare the efficacy, safety, and histological quality of ESD performed using this novel versatile knife and a combination of several conventional knives. Methods This was an in vivo animal study comparing two different modalities of ESD in mini-pigs. Completion time of each resection was documented, and the resected specimens were retrieved and evaluated for completeness. To assess the quality control of the procedures and adverse events, detailed histopathological examinations were performed. Results A total of 18 specimens were dissected by ESD safely and easily (nine specimens using the new versatile knife; nine specimens by mixing conventional knives). All resections were completed as en bloc resections. There was no significant difference in procedure time between the 2 modalities (456 seconds vs. 355 seconds, p=0.258) and cutting speed (1.983 mm2/sec vs. 1.57 mm2/sec, p=1.000). The rate of adverse events and histological quality did not statistically differ between the modalities. Conclusions ESD with a versatile knife appeared to be an easy, safe, and technically efficient method. PMID:25505721

  11. Relaxing music for anxiety control.

    PubMed

    Elliott, Dave; Polman, Remco; McGregor, Richard

    2011-01-01

    The purpose of this investigation was to determine the characteristics of relaxing music for anxiety control. Undergraduate students (N=84) were instructed to imagine themselves in an anxiety producing situation while listening to a selection of 30 music compositions. For each composition, level of relaxation, the factors that either enhanced or detracted from its relaxing potential and the emotional labels attached were assessed. Participants were also asked to state which music components (e.g., tempo, melody) were most conducive to relaxation. Additional information was obtained through the use of a focus group of 6 undergraduate music students. This paper presents details on the characteristics of relaxing-music for anxiety control and emotional labels attached to the relaxing compositions. Furthermore, an importance value has been attached to each of the music components under scrutiny, thus providing an indication of which music components should receive greatest attention when selecting music for anxiety control. PMID:22097099

  12. The Umbilical Benz Incision for Reduced Port Surgery in Pediatric Patients

    PubMed Central

    Amano, Hizuru; Kawashima, Hiroshi; Deie, Kyoichi; Murase, Naruhiko; Makita, Satoshi; Yokota, Kazuki; Tanaka, Yujiro

    2015-01-01

    Background and Objectives: For reduced port surgery in pediatric patients, the initial umbilical incision plays an important role in both functional ability and cosmetic impact. Larger umbilical incisions enable better manipulation of forceps, extraction of larger surgical specimens, and easier exteriorization of the intestine for anastomosis. We have pursued an incision of the small pediatric umbilicus that allows for enlargement of the orifice of the abdominal opening with preservation of the natural umbilical profile. This article aims to present a new umbilical incision technique and describe the outcomes. Methods: We devised a new umbilical incision technique for reduced port surgery in pediatric patients. Our incision is made in an inverted Y shape (Benz incision), allowing for access port device insertion. The Benz incision technique was applied between November 2010 and May 2014 and was retrospectively studied. Results: Seventy-five patients underwent Benz incisions. The median age of all patients was 6 years 6 months (range, 26 days to 18 years), and the median body weight was 21.7 kg (range, 3.1–54.3 kg). Benz incisions were applied for various procedures, including reduced port surgery with hepaticojejunostomy for congenital biliary dilatation, portojejunostomy for biliary atresia, Meckel diverticulectomy, tumor resection, varicocelectomy, cholecystectomy, splenectomy, ileus surgery, ileocecal resection, and total colectomy. All patients were successfully treated, without a significant increase in operating time or severe complications. The cosmetic profile of the umbilicus was maintained after surgery. Conclusion: The Benz incision is a feasible, effective, and scarless approach for reduced port surgery in pediatric patients whose umbilical rings are too small for the conventional approach. PMID:25848185

  13. Renormalized reaction and relaxation rates

    NASA Astrophysics Data System (ADS)

    Gorbachev, Yuriy E.

    2016-06-01

    Impact of the non-equilibrium on the reaction and relaxation rates (called as generalized relaxation rates - GRR), for the spatially inhomogeneous gas mixture is considered. Discarding the assumption that the 'chemical' part of the collisional integral is a small correction to non-reactive part, the expression for the zero-order GRR is derived. They are represented as a renormalization of the traditional reaction and relaxation rates, which means mixing of all corresponding processes. Thus all reactions and relaxation processes are entangled.

  14. Effects of pinacidil on changes to the microenvironment around the incision site, of a skin/muscle incision and retraction, in a rat model of postoperative pain

    PubMed Central

    CAO, SU; QIN, YINBIN; CHEN, JUNJIE; SHEN, SHIREN

    2015-01-01

    The aim of the present study was to evaluate the influence of the microenvironment around an incision site, on peripheral and central sensitization. The effects of pinacidil activation of ATP-sensitive potassium (KATP) channels prior to skin/muscle incision and retraction (SMIR) surgery were assessed. A total of 24 male Sprague Dawley rats were randomly assigned to four groups: Control, sham (incision operation), SMIR (incision plus retraction 1 h after the skin/muscle incision) and pinacidil (SMIR plus pinacidil). The rats in the pinacidil group were intraperitoneally injected with pinacidil prior to the SMIR procedure. The mechanical withdrawal threshold (MWT) was determined at each time point. The microvessel density (MVD) value was determined by immunohistochemistry, and western blotting was performed to analyze the relative protein expression levels of nerve growth factor (NGF), glucose transporter protein-1 (GLUT1) and C-jun N-terminal kinases. There was a significant reduction in the levels of MVD, GLUT1 and MWT following SMIR surgery as compared with the incision alone, and a significant increase in the NGF protein expression levels. In the SMIR group, the MVD value was significantly increased seven days after surgery, as compared with three days after surgery. Additionally, intraperitoneal administration of pinacidil prior to the SMIR surgery inhibited the SMIR-induced reduction in MWT and MVD and attenuated the SMIR-induced GLUT1 reduction. The results of the present study suggest that the microenvironment around an incision site may affect the development of peripheral and central sensitization. In addition, pinacidil had an inhibitory effect on the formation of the inflammatory microenvironment around the incision site through activation of KATP channels, thereby inhibiting peripheral and central sensitization. PMID:25760986

  15. Nucleus management in manual small incision cataract surgery by phacosection.

    PubMed

    Ravindra, M S

    2009-01-01

    Nucleus management is critical in manual small incision cataract surgery (MSICS), as the integrity of the tunnel, endothelium and posterior capsule needs to be respected. Several techniques of nucleus management are in vogue, depending upon the specific technique of MSICS. Nucleus can be removed in toto or bisected or trisected into smaller segments. The pressure in the eye can be maintained at the desired level with the use of an anterior chamber maintainer or kept at atmospheric levels. In MSICS, unlike phacoemulsification, there is no need to limit the size of the tunnel or restrain the size of capsulorrhexis. Large well-structured tunnels and larger capsulorrhexis provide better control on the surgical maneuvers. Safety and simplicity of MSICS has made it extremely popular. The purpose of this article is to describe nucleus management by phacosection in MSICS. PMID:19075409

  16. Mandibular incisive canal in relation to periapical surgery

    PubMed Central

    Bilginaylar, Kani; Orhan, Kaan; Uyanik, Lokman Onur

    2016-01-01

    The aim of the present paper is to emphasize the importance of the mandibular interforaminal neurovascular bundle with a case and make a warning to dentists and surgeons during oral and maxillofacial surgeries, such as implant replacement, bone harvesting, genioplasty, open reduction of a mandibular fracture, and cyst enucleations at this region. In this paper, we present a 58-year-old male who referred with pain and a tingling sensation on the left lower lip. After radiographical, extraoral and intraoral examinations, findings indicated the lesion to be a cyst which was related with a periapical lesion of the canine tooth and extracted socket of first premolar tooth. After removal of a cyst, the mandibular incisive nerve was documented which was in relation to cyst cavity. PMID:27041907

  17. Comparative analyses of linac and Gamma Knife radiosurgery for trigeminal neuralgia treatments

    NASA Astrophysics Data System (ADS)

    Ma, L.; Kwok, Y.; Chin, L. S.; Yu, C.; Regine, W. F.

    2005-11-01

    Dedicated linac-based radiosurgery has been reported for trigeminal neuralgia treatments. In this study, we investigated the dose fall-off characteristics and setup error tolerance of linac-based radiosurgery as compared with standard Gamma Knife radiosurgery. In order to minimize the errors from different treatment planning calculations, consistent imaging registration, dose calculation and dose volume analysis methods were developed and implemented for both Gamma Knife and linac-based treatments. Intra-arc setup errors were incorporated into the treatment planning process of linac-based deliveries. The effects of intra-arc setup errors with increasing number of arcs were studied and benchmarked against Gamma Knife deliveries with and without plugging patterns. Our studies found equivalent dose fall-off properties between Gamma Knife and linac-based radiosurgery given a sufficient number of arcs (>7) and small intra-arc errors (<0.5 mm) were satisfied for linac-based deliveries. Increasing the number of arcs significantly decreased the variations in the dose fall-off curve at the low isodose region (e.g. from 40% to 10%) and also improved dose uniformity at the high isodose region (e.g. from 70% to 90%). As the number of arcs increased, the effects of intra-arc setup errors on the dose fall-off curves decreased. Increasing the number of arcs also reduced the integral dose to the distal normal brain tissues. In conclusion, linac-based radiosurgery produces equivalent dose fall-off characteristics to Gamma Knife radiosurgery with a high number of arcs. However, one must note the increased treatment time for a large number of arcs and isocentre accuracies.

  18. A 1-D morphodynamic model of postglacial valley incision

    NASA Astrophysics Data System (ADS)

    Tunnicliffe, Jon F.; Church, Michael

    2015-11-01

    Chilliwack River is typical of many Cordilleran valley river systems that have undergone dramatic Holocene degradation of valley fills that built up over the course of Pleistocene glaciation. Downstream controls on base level, mainly blockage of valleys by glaciers, led to aggradation of significant glaciofluvial and glaciolacustrine valley fills and fan deposits, subsequently incised by fluvial action. Models of such large-scale, long-term degradation present a number of important challenges since the evolution of model parameters, such as the rate of bedload transport and grain size characteristics, are governed by the nature of the deposit. Sediment sampling in the Chilliwack Valley reveals a complex sequence of very coarse to fine textural modes. We present a 1-D numerical morphodynamic model for the river-floodplain system tailored to conditions in the valley. The model is adapted to dynamically adjust channel width to optimize sediment transporting capacity and to integrate relict valley fill material as the channel incises through valley deposits. Sensitivity to model parameters is studied using four principal criteria: profile concavity, rate of downstream grain size fining, bed surface sand content, and the timescale to equilibrium. Model results indicate that rates of abrasion and coarsening of the grain size distributions exert the strongest controls on all of the interrelated model performance criteria. While there are a number of difficulties in satisfying all model criteria simultaneously, results indicate that 1-D models of valley bottom sedimentary systems can provide a suitable framework for integrating results from sediment budget studies and chronologies of sediment evacuation established from dating.

  19. SINGLE-INCISION VIDEOLAPAROSCOPIC APPENDECTOMY WITH CONVENTIONAL VIDEOLAPAROSCOPY EQUIPMENT

    PubMed Central

    PINHEIRO, Rodrigo Nascimento; SOUSA, Renato Costa; CASTRO, Fernanda Mesquita de Brito; de ALMEIDA, Roberta Oliveira; GOUVEIA, Gustavo de Castro; de OLIVEIRA, Viviane Rezende

    2014-01-01

    Background Acute appendicitis is the most common surgical emergency in daily practice, and is approached laparoscopically in many centers. Efforts have been undertaken for the development of minimally invasive techniques that reduce tissue trauma and offer improved cosmetic results, one of such being the single-incision laparoscopic surgery (SILS). Aim To present a minimally invasive technique for appendectomy (SILS) undertaken with conventional instruments. Method Eleven patients were treated in the emergency care center presenting abdominal pain in the right iliac fossa that was suggestive of appendicitis. Diagnostic investigation was subsequently conducted, including physical examination, laboratory and imaging exams (CT scan with intravenous contrast or total abdominal ultrasound), and the results were consistent with acute appendicitis. Thus, after consent, these patients underwent SILS appendectomy under general anesthesia with three trocars (two 10 mm and one 5 mm), using conventional and optical laparoscopic tweezers (10 mm, 30º). The base and pedicle of the appendix were ligated with titanium LT 400 clips. The procedure occurred uneventfully. Inclusion criteria were absence of diffuse peritonitis, BMI (body mass index) less than 35 and absence of serious comorbidities or sepsis. Results Seven men and four women were operated with average age of 25.7 years and underwent appendectomy through this technique. Mean procedure duration was of 37.2 min. Regarding surgical findings, three had appendicitis in stage 1, four in stage 2 and four in stage 3. All patients improved well, without surgical complications, and did not require conversion to open surgery or conventional laparoscopy technique. Conclusion Appendectomy conducted through Single Incision Laparoscopic Surgery is a feasible and promising technique that can be performed with conventional laparoscopic instruments. PMID:24676296

  20. Comet Bursting Through Relaxation

    NASA Astrophysics Data System (ADS)

    Jacobson, Seth A.; Scheeres, D. J.

    2012-10-01

    Comets may be excited and occupy non-principal axis (complex) rotation states for a large fraction of their lifetimes. Many comet nuclei have been identified or are suspected to occupy non-principal axis (complex) rotation [Belton 2005, etc.] as well as have evolving rotation rates [Belton 2011, etc.]. Comet orbits drive these rotation states through cycles of excitation due to surface jets and relaxation due to time variable internal stresses that dissipate energy in the anelastic comet interior. Furthermore, relaxation from complex rotation can increase the loads along the symmetry axis of prolate comets. These loads stretch the body along the symmetry axis and may be the cause of the characteristic ``bowling pin’’ shape and eventually may lead to failure. This is an alternative model for comet bursting. Each cycle deposits only a small amount of energy and stress along the axis, but this process is repeated every orbit during which jets are activated. Our model for the evolution of comet nuclei includes torques due to a number of discrete jets located on the surface based on Neishtadt et al. [2002]. The model also includes internal dissipation using an approach developed by Sharma et al. [2005] and Vokrouhlicky et al. [2009]. These equations are averaged over the instantaneous spin state and the heliocentric orbit so the long-term evolution of the comet can be determined. We determine that even after the inclusion of internal dissipation there still exist non-principal axis equilibrium states for certain jet geometries. For ranges of dissipation factors and jet geometries, prolate comets are found to occupy states that have time variable internal loads over long time periods. These periodic loadings along the symmetry axis may lead to ``necking’’ as the body extends along the axis to release the stress and eventually disruption.

  1. MRI-based polymer gel dosimetry for validating plans with multiple matrices in Gamma Knife stereotactic radiosurgery.

    PubMed

    Gopishankar, N; Watanabe, Yoichi; Subbiah, Vivekanandhan

    2011-01-01

    One of treatment planning techniques with Leksell GammaPlan (LGP) for Gamma Knife stereotactic radiosurgery (GKSRS) uses multiple matrices with multiple dose prescriptions. Computational complexity increases when shots are placed in multiple matrices with different grid sizes. Hence, the experimental validation of LGP calculated dose distributions is needed for those cases. For the current study, we used BANG3 polymer gel contained in a head-sized glass bottle to simulate the entire treatment process of GKSRS. A treatment plan with three 18 mm shots and one 8 mm shot in separate matrices was created with LGP. The prescribed maximum dose was 8 Gy to three shots and 16 Gy to one of the 18 mm shots. The 3D dose distribution recorded in the gel dosimeter was read using a Siemens 3T MRI scanner. The scanning parameters of a CPMG pulse sequence with 32 equidistant echoes were as follows: TR = 7 s, echo step = 13.6 ms, field-of-view = 256 mm × 256 mm, and pixel size = 1 mm × 1 mm. Interleaved acquisition mode was used to obtain 15 to 45 2-mm-thick slices. Using a calibration relationship between absorbed dose and the spin-spin relaxation rate (R2), we converted R2 images to dose images. MATLAB-based in-house programs were used for R2 estimation and dose comparison. Gamma-index analysis for the 3D data showed gamma values less than unity for 86% of the voxels. Through this study we accomplished the first application of polymer gel dosimetry for a true comparison between measured 3D dose distributions and LGP calculations for plans using multiple matrices for multiple targets. PMID:21587176

  2. Stepladder incision technique for radical excision of suprasternal thyroglossal duct remnant.

    PubMed

    Ceccanti, Silvia; Frediani, Simone; Morgante, Debora; Iaconelli, Romina; Mele, Ermelinda; Cozzi, Denis A

    2011-10-01

    Thyroglossal duct remnant localized to the suprasternal notch is an exceedingly rare condition. We report on a novel case occurring in an 8-year-old girl who presented with acute onset of a suprasternal abscess. After incision and drainage, a Sistrunk procedure was successfully carried out using 2 stepladder incisions. This approach combined optimal surgical exposure and satisfactory cosmesis. PMID:22008349

  3. Minimizing Surgically Induced Astigmatism at the Time of Cataract Surgery Using a Square Posterior Limbal Incision

    PubMed Central

    Ernest, Paul; Hill, Warren; Potvin, Richard

    2011-01-01

    Purpose. To compare the surgically induced astigmatism from clear corneal and square posterior limbal incisions at the time of cataract surgery. Methods. Surgically induced astigmatism was calculated for a set of eyes after cataract surgery using a temporal 2.2 mm square posterior limbal incision. Results were compared to similar available data from surgeons using clear corneal incisions of similar size. Results. Preoperative corneal astigmatism averaged 1.0 D and was not significantly different between the incision types. Surgically induced astigmatism with the 2.2 mm posterior limbal incision averaged 0.25 ± 0.14 D, significantly lower in magnitude than the aggregate surgically induced astigmatism produced by the 2.2 mm clear corneal incision (0.68 ± 0.49 D). Conclusion. The 2.2 mm square posterior limbal incision induced significantly less, and significantly less variable, surgically induced astigmatism relative to a similar-sized clear corneal incision. This is likely to improve refractive outcomes, particularly important with regard to premium intraocular lenses. PMID:22132310

  4. Turkish surgeons’ experiences and perception about single-incision laparoscopic surgery

    PubMed Central

    Aktimur, Recep; Çetinkünar, Süleyman; Yıldırım, Kadir

    2016-01-01

    Objective: We aimed to show Turkish surgeons’ current status of experience and perception about single-incision laparoscopic surgery. Material and Methods: The experience and perception of general surgeons, who were members of the Turkish Surgical Association (3.5%, 116/3312), about single-incision laparoscopic surgery were analyzed according to demographic characteristics and a self-report questionnaire with the following four domains: surgeons’ perception regarding the performance of single-incision laparoscopic surgery in their clinical practice; their experience of laparoscopic surgery; education, experience, and attitude for single-incision laparoscopic surgery; and the reason for performing/not performing single-incision laparoscopic surgery in their practice. Results: There were no significant factors affecting Turkish surgeons’ preference of surgical approach. Although, most surgeons performing single-incision laparoscopic surgery were educated (72.2%), the dominant factor driven them to perform this surgery seemed to be personal achievement and satisfaction (57%). Most surgeons who did not perform single-incision laparoscopic surgery were not interested to do so and considered it unnecessary (62.1%). In addition, the need for special equipment and training were dominant barriers (61%). Conclusion: It seems that Turkish surgeons’ perception to perform single-incision laparoscopic surgery was more related to their personal achievement and satisfaction. PMID:27436932

  5. Incisal margin condition after LEEP for cervical intraepithelial neoplasia patients and prognosis

    PubMed Central

    Chen, Hong; Liu, Xiufeang; Xu, Lina

    2016-01-01

    The aim of the study was to examine the relationship between incisal condition after loop electrosurgical excision procedure (LEEP) operation for cervical intraepithelial neoplasia (CIN) patients and prognosis. A study of high-risk incisal margin positive cases was also performed. We compared the differences in the prognosis of the 1-year follow-up visit in the 120 CIN patients admitted to the hospital during the period from April 2013 to April 2014. A total of 43 cases of positive incisal margin (35.8%), and 77 negative cases were included in the study. The differences in age, course of disease, and CIN level between the two groups showed no statistical significance (P>0.05). In the positive group, the positive ratio was significantly higher than that of the negative group (P<0.05). The positive incisal margin showed a significant positive correlation with human papillomavirus (HPV) positivity (r=0.327, P=0.035). The condition of most patients with positive incisal margin and HPV was critical, which was followed by positive incisal margin and negative HPV. The patients with the best prognosis were those with significant negative incisal margin as well as HPV (P<0.05). In conclusion, the positive incisal margin after LEEP operation was associated with relapse of the disease. Thus, considering the HPV test into consideration is valuable for the prognosis of the disease. PMID:27446314

  6. Double incision wound healing bioassay using Hamelia patens from El Salvador.

    PubMed

    Gomez-Beloz, Alfredo; Rucinski, James C; Balick, Michael J; Tipton, Camille

    2003-10-01

    Hamelia patens Jacq. (Rubiaceae) has received little attention in the laboratory for its wound healing ability even though it is commonly used as a treatment for wounds throughout Central America. A double incision wound healing bioassay was carried out with a crude extract of Hamelia patens collected from El Salvador. Animals were divided into three groups. Group I (n = 14) had the left incision treated with 5% (w/w) Hamelia patens and the contralateral side with petroleum jelly (PJ). Group II (n = 14) had the left incision treated with 10% (w/w) ointment and the contralateral side with petroleum jelly. Group III (n = 10) had the left incision treated with petroleum jelly and the contralateral side left untreated. Breaking strength of the incisions was measured on day 7 and day 12. For Groups I and II, there was no significant difference between treatment and control incisions at day 7. On day 12, there was a significant difference between the treated and control incisions for Groups I and II. There was no significant difference between petroleum jelly and untreated incisions for Group III on day 7 and day 12. Hamelia patens does increase breaking strength of wounds significantly more than the control group. Further wound healing studies of this plant are warranted. PMID:12963138

  7. Measuring the Longitudinal NMR Relaxation Rates of Fast Relaxing Nuclei Using a Signal Eliminating Relaxation Filter

    NASA Astrophysics Data System (ADS)

    Hansen, D. Flemming; Led, Jens J.

    2001-08-01

    A new experiment for selective determination of the relaxation rates of fast relaxing NMR signals is presented. The experiment is derived from the conventional inversion recovery experiment by substituting the 180° inversion pulse of this experiment with a signal eliminating relaxation filter (SERF) consisting of three 180° pulses separated by two variable delays, Δ1 and Δ2. The SERF experiment allows a selective suppression of signals with relaxation rates below a given limit while monitoring the relaxation of faster relaxing signals. The experiment was tested on a sample of 20% oxidized plastocyanin from Anabaena variabilis, where the fast exchange of an electron between the reduced (diamagnetic) and the oxidized (paramagnetic) form results in a series of average signals with widely different relaxation rates. To ensure an optimum extraction of information from the experimental data, the relaxation rates were obtained from the SERF experiment by a simultaneous analysis of all the FIDs of the experiment using a fast linear prediction model method developed previously. The reliability of the relaxation rates obtained from the SERF experiment was confirmed by a comparison of the rates with the corresponding rates obtained from a conventional inversion recovery experiment.

  8. The effect and clinical application of homemade tracheotomy incision nursing pads.

    PubMed

    Yao, Yachun; Xu, Li; Du, Kun; Zhang, Jiajun

    2014-09-01

    To investigate the effect and clinical application of the homemade tracheotomy incision nursing pads. 83 patients suffering tracheotomy were randomly divided into experimental and control groups. The experimental group was treated with the homemade tracheotomy incision nursing pads, and the control group was treated with the traditional tracheotomy nursing pads. Subsequently, the number of nursing pads used in 2 weeks, tracheotomy incision bacterial colonies and the comfort of patient between the two groups of pads was compared. The number of nursing pads used by the experimental group was smaller than the control group, and the tracheotomy incision bacterial colonies in the experimental group were fewer than the control group (P < 0.01). However, the differences observed for the skin irritation and gas permeability between the two groups were not statistically significant (P > 0.05). Thus, the results show that the effect of homemade tracheotomy incision nursing pads is greater compared to the traditional nursing pads. PMID:24633484

  9. Pulmonary function after transverse or midline incision in patients with obstructive pulmonary disease.

    PubMed

    Becquemin, J P; Piquet, J; Becquemin, M H; Melliere, D; Harf, A

    1985-01-01

    Atelectasis and bronchopneumonia occur frequently in patients undergoing aorto-iliac reconstructive surgery. Transverse (T) incisions in upper abdominal surgery are thought to be followed by fewer pulmonary complications than midline incisions (M) but reports remain controversial. We studied the incidence of postoperative pulmonary complications and lung dysfunction after T and M incisions for aorto-iliac surgery in 13 patients with chronic obstructive pulmonary disease (COPD) and 13 control patients with normal lungs (C). For all subjects, we evaluated (1) postoperative clinical or radiological pulmonary events; (2) preoperatively and on postoperative days 2 (D2), 5 (D5), 9 (D9) and 12 (D12) - the forced expiratory volume in 1 s (FEV1), vital capacity (VC), alveolar-arterial oxygen difference (AaPO2), and (3) convenience for the surgeon. Operatively, aortic exposure was excellent with both incisions. Bronchopneumonia occurred only after M in five patients (1 C, 4 COPD). In contrast with the control patients in whom no difference was found between T and M incisions, the FEV1 of COPD patients was significantly less impaired with T than with M incisions (p less than 0.005 on D2 and p less than 0.05 on D5). VC decreased similarly with both incisions on D2 but on D5 the improvement was less with M (p less than 0.005). Changes in AaPO2 were more marked on D2 and D5 for the COPD patients with M incisions. We conclude that (1) in patients with chronic obstructive pulmonary disease, laparotomy with a transverse incision was associated with better postoperative lung function and fewer pulmonary complications; (2) in patients without pulmonary disease, midline and transverse incisions were equivalent. PMID:2933436

  10. Gamma Knife surgical treatment for partially embolized cerebral arteriovenous malformations.

    PubMed

    Huo, Xiaochuan; Jiang, Yuhua; Lv, Xianli; Yang, Hongchao; Zhao, Yang; Li, Youxiang

    2016-03-01

    OBJECT A combination of embolization and radiosurgery is used as a common strategy for the treatment of large and complex cerebral arteriovenous malformations (AVMs). This study presents the experiences of partially embolized cerebral AVMs followed by Gamma Knife surgery (GKS) and assesses predictive factors for AVM obliteration and hemorrhage. METHODS The interventional neuroradiology database that was reviewed included 404 patients who underwent AVM embolization. Using this database, the authors retrospectively analyzed all partially embolized AVM cases followed by GKS for a residual nidus. Except for cases of complete AVM obliteration, the authors excluded all patients with radiological follow-up of less than 2 years. Logistic regression analysis was used to analyze the predictive factors related to AVM obliteration and hemorrhage following GKS. Kaplan-Meier analysis was used to evaluate the obliteration with a cutoff AVM nidus volume of 3 cm(3) and 10 cm(3). RESULTS One hundred sixty-two patients qualified for the study. The median patient age was 26 years and 48.8% were female. Hemorrhage presented as the most common symptom (48.1%). The median preembolization volume of an AVM was 14.3 cm(3). The median volume and margin dose for GKS were 10.92 cm(3) and 16.0 Gy, respectively. The median radiological and clinical follow-up intervals were 47 and 79 months, respectively. The annual hemorrhage rate was 1.71% and total obliteration rate was 56.8%. Noneloquent area (p = 0.004), superficial location (p < 0.001), decreased volume (p < 0.001), lower Spetzler-Martin grade (p < 0.001), lower Virginia Radiosurgery AVM Scale (RAS; p < 0.001), lower Pollock-Flickinger score (p < 0.001), lower modified Pollock-Flickinger score (p < 0.001), increased maximum dose (p < 0.001), and increased margin dose (p < 0.001) were found to be statistically significant in predicting the probability of AVM obliteration in the univariate analysis. In the multivariate analysis, only volume

  11. Two-year experience with the commercial Gamma Knife Check software.

    PubMed

    Xu, Andy Yuanguang; Bhatnagar, Jagdish; Bednarz, Greg; Novotny, Josef; Flickinger, John; Lunsford, L Dade; Huq, M Saiful

    2016-01-01

    The Gamma Knife Check software is an FDA approved second check system for dose calculations in Gamma Knife radiosurgery. The purpose of this study was to evaluate the accuracy and the stability of the commercial software package as a tool for independent dose verification. The Gamma Knife Check software version 8.4 was commissioned for a Leksell Gamma Knife Perfexion and a 4C unit at the University of Pittsburgh Medical Center in May 2012. Independent dose verifications were performed using this software for 319 radiosurgery cases on the Perfexion and 283 radiosurgery cases on the 4C units. The cases on each machine were divided into groups according to their diagnoses, and an averaged absolute percent dose difference for each group was calculated. The percentage dose difference for each treatment target was obtained as the relative difference between the Gamma Knife Check dose and the dose from the tissue maximum ratio algorithm (TMR 10) from the GammaPlan software version 10 at the reference point. For treatment plans with imaging skull definition, results obtained from the Gamma Knife Check software using the measurement-based skull definition method are used for comparison. The collected dose difference data were also analyzed in terms of the distance from the treatment target to the skull, the number of treatment shots used for the target, and the gamma angles of the treatment shots. The averaged percent dose differences between the Gamma Knife Check software and the GammaPlan treatment planning system are 0.3%, 0.89%, 1.24%, 1.09%, 0.83%, 0.55%, 0.33%, and 1.49% for the trigeminal neuralgia, acoustic neuroma, arteriovenous malformation (AVM), meningioma, pituitary adenoma, glioma, functional disorders, and metastasis cases on the Perfexion unit. The corresponding averaged percent dose differences for the 4C unit are 0.33%, 1.2%, 2.78% 1.99%, 1.4%, 1.92%, 0.62%, and 1.51%, respectively. The dose difference is, in general, larger for treatment targets in the

  12. Transurethral optical-laser knife and probe director for lateral firing laser probes

    NASA Astrophysics Data System (ADS)

    Malek, Reza S.

    1994-02-01

    Laser energy has been used by many for transurethral incision of small, obstructive prostates, vesical neck contractures, and urethral strictures. The customary techniques of moving the tip of the laser fiber through a cystoscope with a conventional laser guide, almost tangentially to the tissue to be incised, or drilling radially arranged holes in the scar, or both, have been cumbersome and imprecise. To provide exact control of the laser fiber and precise delivery of laser energy, a new guide was devised. It conducts the quartz fiber through the sheath and along the lens of an optical urethrotome. The tip of the quartz fiber contacts the tissue at an angle of 20 degree(s). KTP/532 laser energy is used to perform internal urethrotomy for urethral stricture, transurethral incision of postoperative contracture of the vesical neck, and transurethral incision of the small prostate under constant visual control.

  13. Corneal Optical Quality Following Sub 1.8 mm Micro-Incision Cataract Surgery vs. 2.2 mm Mini-Incision Coaxial Phacoemulsification

    PubMed Central

    Alió, Jorge L.; Elkady, Bassam; Ortiz, Dolores

    2010-01-01

    Purpose: To study and compare the effects of the micro-incision cataract surgery (MICS-sub 1.8 mm) and miniincision coaxial phacoemulsification (2.2 mm) on the optical quality of the cornea characterized in terms of corneal aberrations. Materials and Methods: Fifty eyes underwent MICS and 50 mini-incision phacoemulsification, by the same surgeon. Both types of cataract surgery were performed using low ultrasound power and through a clear corneal incision, placed on the steepest corneal meridian ranging from 1.6 to 1.8 in MICS (Group I) and from 2.12 to 2.3 mm in mini-incision coaxial phacoemulsification (Group II). Seidel and Zernike aberration coefficients and RMS values were obtained for a 6-mm pupil preoperatively and one month after surgery. Results: The corneal astigmatism did not show statistically significant changes in either of the two groups: (MICS: –0.73 ± 0.63, –0.65 ± 0.53 D, P = 0.25), (mini-incision phacoemulsification; –1.21 ± 1.52, –1.00 ± 1.19 D, P = 0.12). The total RMS remained unchanged after MICS (1.77 ± 1.7, 1.65 ± 1.3 μm, P = 0.18) and mini-incision phacoemulsification (2.00 ± 1.87, 2.09 ± 1.8 μm, P = 0.41). Statistically significant changes were found for coma (P = 0.004) and higher-order aberrations (P < 0.001), showing MICS significantly less changes in cornea. Conclusions: Both MICS and mini-incision phacoemulsification do not degrade the optical quality of the cornea. Both surgeries do not induce a modification of the corneal astigmatism, even in the axis. It seems that 2 mm is the limit around which no optical changes are induced by cataract surgery in the human cornea. PMID:20543945

  14. Bipolar plasma vaporization versus monopolar TUR and “cold-knife" TUI in secondary bladder neck sclerosis – An evidence based, retrospective critical comparison in a single center clinical setting

    PubMed Central

    Moldoveanu, C; Geavlete, B; Jecu, M; Stanescu, F; Adou, L; Bulai, C; Ene, C; Geavlete, P

    2014-01-01

    Introduction: A long term, retrospective study was performed aiming to outline a critical comparison concerning the efficacy, safety and durability of the bipolar plasma vaporization (BPV), standard monopolar transurethral resection (TUR) and “cold-knife" “star" transurethral incision (TUI) in secondary bladder neck sclerosis (BNS) cases. Materials & Methods: Of the 126 patients included in the trial based on maximum flow rate (Qmax) below 10 mL/s and International Prostate Symptom Score (IPSS) over 19, classical resection was performed in 46 cases, “cold-knife" TUI in 37 cases and bipolar vaporization in 43 patients. The evaluation protocol comprised IPSS, QoL (quality of life) score, Qmax and PVR (post-voiding residual urinary volume) assessment performed at 1, 3, 6, 12, 18 and 24 months after the initial intervention. Results: Significant intraoperative complications (capsular perforation – 8.7%; bleeding – 4.3%) occurred secondary to monopolar resection. “Star" TUI was the fastest technique, followed by plasma-button vaporization (7.2 and 11.4 versus 16.5 minutes). BPV and TUI patients benefitted from the shortest catheterization periods (0.75 and 1 versus 2.0 days) and hospital stays (1.0 and 1.25 versus 2.0 days). Immediate postoperative adverse events consisted of hematuria (6.5% of the TUR cases) and acute urinary retention (8.1% of the TUI group). Significantly higher long term BNS recurrence rates requiring re-treatment were established in the TUI (18.7%) and TUR (12.8%) series by comparison to BPV (5.4%). Among patients that completed the follow-up protocol, equivalent IPSS, QoL, Qmax and PVR features were determined in the 3 study arms. Conclusions: The plasma vaporization approach was confirmed as a successful match to conventional TUR and “cold-knife" TUI in terms of surgical safety profile, postoperative recovery, therapeutic durability and urodynamic and symptom score parameters. PMID:24653766

  15. Brain relaxation and cerebrospinal fluid pressure during craniotomy for resection of supratentorial mass lesions.

    PubMed

    Turner, C R; Losasso, T J; Muzzi, D A; Weglinski, M R

    1996-04-01

    Neurosurgery can be complicated by the clinical situation commonly referred to as "tight brain," in which the brain presses against the inner table of the skull or protrudes through the craniotomy site. We report here a retrospective study of 32 patients who had undergone elective craniotomy for resection of supratentorial mass lesions. We determined the relationship between lumbar cerebrospinal fluid pressure (CSFP) and brain relaxation and whether brain relaxation varies with anesthetic technique. Patients had received one of four anesthetic techniques: 1 MAC isoflurane (ISO), 1 MAC desflurane (DES), 50% N2O with 0.5 MAC ISO, or 50% N2O with 0.5 MAC DES. Lumbar CSFP had been recorded before the induction of anesthesia (baseline) and immediately prior to dural incision. Charts were retrospectively reviewed for evidence of tight brain, which was considered present if mannitol had been administered, CSF had been drained via the lumbar needle, or the surgical dictation noted the brain was tight at the time of dural incision. Tight brain occurred in 10 of 32 patients. CSFP (mean +/- SD) was significantly greater in the tight than in the nontight group both at baseline (11 +/- 5 vs. 8 +/- 3 mm Hg, p < 0.05) and immediately prior to dural incision (13 +/- 7 vs. 9 +/- 4 mm Hg, p < 0.05). Tight brain did not occur in any patient with CSFP < 6 mm Hg, but it did occur in all patients with CSFP > 17 mm Hg. Within the range of 6-17 mm Hg, CSFP was not predictive of brain relaxation. Tight brain was more common in patients receiving 1 MAC ISO or DES (9 of 20 patients; 45%) than in patients receiving 0.5 MAC ISO or DES with 50% N2O (1 of 12 patients; 8%, p < 0.05). We conclude that in patients undergoing elective craniotomy for resection of a supratentorial mass lesion, brain relaxation is not predictive of CSFP. Although CSFP values at the extremes of the observed distribution ( > 17 mm Hg or < 6 mm Hg) did correlate with brain relaxation, within the range of 6-17 mm Hg, CSFP

  16. Evaluation of holmium laser versus cold knife in optical internal urethrotomy for the management of short segment urethral stricture

    PubMed Central

    Jain, Sudhir Kumar; Kaza, Ram Chandra Murthy; Singh, Bipin Kumar

    2014-01-01

    Objectives: Sachse cold knife is conventionally used for optical internal urethrotomy intended to manage urethral strictures and Ho: YAG laser is an alternative to it. The aim of this study was to evaluate the role of urethral stricture treatment outcomes, efficacy, and complications using cold knife and Ho: YAG (Holmium laser) for optical internal urethrotomy Materials and Methods: In this prospective study included, 90 male patients age >18 years, with diagnosis of urethral stricture admitted for internal optical urethrotomy during April 2010 to March 2012. The patients were randomized into two groups containing 45 patients each using computer generated random number. In group A (Holmium group), internal urethrotomy was done with Holmium laser and in group B (Cold knife group) Sachse cold knife was used. Patients were followed up for 6 months after surgery in Out Patient Department on 15, 30 and 180 post-operative days. At each follow up visit physical examination, and uroflowmetry was performed along with noting complaints, if any. Results: The peak flow rates (PFR) were compared between the two groups on each follow up. At 180 days (6 month interval) the difference between mean of PFR for Holmium and Cold knife group was statistically highly significant (P < 0.001). Complications were seen in 12.22% of cases. Conclusion: Both modalities are effective in providing immediate relief to patients with single and short segment (<2 cm long) urethral strictures but more sustained response was attained with Cold knife urethrotomy. PMID:25371611

  17. Stress Relaxation of Magnetorheological Fluids

    NASA Astrophysics Data System (ADS)

    Li, W. H.; Chen, G.; Yeo, S. H.; Du, H.

    In this paper, the experimental and modeling study and analysis of the stress relaxation characteristics of magnetorheological (MR) fluids under step shear are presented. The experiments are carried out using a rheometer with parallel-plate geometry. The applied strain varies from 0.01% to 100%, covering both the pre-yield and post-yield regimes. The effects of step strain, field strength, and temperature on the stress modulus are addressed. For small step strain ranges, the stress relaxation modulus G(t,γ) is independent of step strain, where MR fluids behave as linear viscoelastic solids. For large step strain ranges, the stress relaxation modulus decreases gradually with increasing step strain. Morever, the stress relaxation modulus G(t,γ) was found to obey time-strain factorability. That is, G(t,γ) can be represented as the product of a linear stress relaxation G(t) and a strain-dependent damping function h(γ). The linear stress relaxation modulus is represented as a three-parameter solid viscoelastic model, and the damping function h(γ) has a sigmoidal form with two parameters. The comparison between the experimental results and the model-predicted values indicates that this model can accurately describe the relaxation behavior of MR fluids under step strains.

  18. De Qeurvian Tenosynovitis: Clinical Outcomes of Surgical Treatment with Longitudinal and Transverse Incision

    PubMed Central

    Abrisham, Syyed Jalil; Karbasi, Mohammad Hosein Akhavan; Zare, Jalil; Behnamfar, Zahra; Tafti, Arefah Dehghani; Shishesaz, Behzad

    2011-01-01

    Objectives De Quervain disease is a mechanical tenosynovitis due to inadequacy volume between abductor pollicis longus, extensor pollicis brevis and their tunnel. Treatment methods include immobilization, steroid injections, and operation. For the first time Fritz De Quervain described surgical treatment of this disease. Since then, various ways of treatment have been reported. The purpose of this study is to compare the clinical outcomes of a longitudinal incision with a transverse incision in De Quervain disease. Methods This was a randomized controlled clinical trial conducted in three hospitals in Iran, Yazd from March 2003 to September 2008. One hundred-twenty patients with De Quervain disease who did not respond to conservative treatment were operated with two different incisions. The patients were followed for three months to compare the surgical outcomes. Results During a three month follow-up, a significant difference was shown between the two methods (p=0.03). Results of surgical treatment with longitudinal incision were excellent (only 5 hypertrophic scars), but there were 13 postoperative complaints with transverse incision. Conclusion According to our findings, longitudinal incision in surgical treatment of De Quervain disease is better than transverse incision. PMID:22043391

  19. Incidence of Port-Site Incisional Hernia After Single-Incision Laparoscopic Surgery

    PubMed Central

    Rainville, Harvey; Ikedilo, Ojinika; Vemulapali, Pratibha

    2014-01-01

    Background and Objectives: Single-incision laparoscopic surgery is gaining popularity among minimally invasive surgeons and is now being applied to a broad number of surgical procedures. Although this technique uses only 1 port, the diameter of the incision is larger than in standard laparoscopic surgery. The long-term incidence of port-site hernias after single-incision laparoscopic surgery has yet to be determined. Methods: All patients who underwent a single-incision laparoscopic surgical procedure from May 2008 through May 2009 were included in the study. Single-incision laparoscopic surgical operations were performed either by a multiport technique or with a 3-trocar single-incision laparoscopic surgery port. The patients were seen at 30 to 36 months' follow-up, at which time they were examined for any evidence of port-site incisional hernia. Patients found to have hernias on clinical examination underwent repairs with mesh. Results: A total of 211 patients met the criteria for inclusion in the study. The types of operations included were cholecystectomy, appendectomy, sleeve gastrectomy, gastric banding, Nissen fundoplication, colectomy, and gastrojejunostomy. We found a port-site hernia rate of 2.9% at 30 to 36 months' follow-up. Conclusion: Port-site incisional hernia after single-incision laparoscopic surgical procedures remains a major setback for patients. The true incidence remains largely unknown because most patients are asymptomatic and therefore do not seek surgical aid. PMID:24960483

  20. Quality of linear incisions performed by dental students using Er:YAG laser in soft tissue

    NASA Astrophysics Data System (ADS)

    Novelli, Moacyr Domingos; Vasques, Mayra Torres; Meneguzzo, Daiane Thaís; Aranha, Ana Cecília Corrêa; Corrêa, Luciana

    2008-02-01

    Introduction: New technologies in dental practice, such as laser, have enabled new strategies to be established in dental education. The aim of this study was to analyze the difficulties that dental students encountered with performing surgical incisions using Er:YAG laser (LE), and the morphology of these incisions. Material and Methods: Sixteen undergraduate dental students and ten dental professionals (DP) enrolled at The Master of Science Program in Laser Dentistry were asked to perform 15 incisions using an LE and 15 with a conventional scalpel. The incisions were compared, based on the shape factor (relation between area and perimeter), which was obtained by a digital image system and by a morphometry software. Data was submitted to statistical analysis of variance (p 0.05). Results: Considering the incisions performed by scalpel, DP showed statistically significant differences (p < 0.01) in relation to control group (CG). Considering the LE, all groups showed significant differences (p<0.0001) in relation to CG, especially the DP group. The main laser technical failures were performing an incision that was not in a straight line, without defined borders, using an inconstant cutting speed, and absence of suction and water jet appliances. None of the groups performed adequate incisions using LE. Conclusion: Greater emphasis is required in relating laser therapy practice to the physical properties of laser, particularly for dental professionals that specialize in laser.

  1. Histologic evaluation of porcine skin incisions produced by CO2 laser, electrosurgery, and scalpel.

    PubMed

    Arashiro, D S; Rapley, J W; Cobb, C M; Killoy, W J

    1996-10-01

    The purpose of this study was to histologically compare the healing of porcine skin incisions made by CO2 laser, electrosurgery, and conventional scalpel. Incisions were made on the dorsal thorax of two microswine at staggered time intervals allowing the harvest of specimens at 0, 4, 7, 14, and 21 days postsurgery at the time of sacrifice. Each of the following histologic zones were identified and measured for both laser and electrosurgery incisions: (1) zone of tissue ablation. (2) zone of thermal necrosis, and (3) width of surface damage. The depth of cut and width of surface opening was measured for the scalpel incision. Furthermore, for each specimen, the presence and character of inflammatory cell infiltrate was noted, as well as the relative times at which bridging of the incision by connective tissue and coverage of the wound by an intact epithelial layer had occurred. Results showed that in this wound-healing model, the scalpel incisions produced more defined borders, healed more rapidly, and resulted in less collateral tissue damage than those produced by CO2 laser or electrosurgery. It was also noted that to create a wound 1.29 mm in depth required at least five passes of the laser beam within the same line of incision using 206.4 J/cm2 (6 W, continuous mode). PMID:9084320

  2. MECHANICAL RESISTANCE OF THE PATELLAR LIGAMENT AFTER REMOVAL OF THE MIDDLE THIRD THROUGH EITHER ONE LONGITUDINAL INCISION OR TWO MINI-TRANSVERSE INCISIONS

    PubMed Central

    De Lazari, Leandro Calil; Paccola, Cleber Antonio Jansen

    2015-01-01

    Objective: To evaluate the resistance and regeneration of the patellar ligament after harvesting a graft for reconstruction of the anterior cruciate ligament, using the traditional technique of a single longitudinal skin incision or a technique of two transverse mini-incisions, in sheep. Methods: Ten sheep were used. In the right knee, we removed the graft using the traditional method, and in the left knee, using the two-incision method. The animals were observed for six months. The specimens (patellar ligament, tibia and patella) were adapted to the mechanical test machine for ligament resistance tests. Results: No difference was found between the two proposed techniques in relation to the regeneration and resistance of the patellar ligament. However, we observed that shortening of the patellar ligament occurred in both groups, and that suturing of the superficial fascia of the patellar ligament did not influence the regeneration of the patellar ligament, according to the histology. Conclusion: The technique using two incisions in the skin presents the same patterns of regeneration and resistance of the remaining patellar ligament as shown by the traditional technique of a single, longitudinal incision. PMID:27022540

  3. Use of Closed Incision Management with Negative Pressure Therapy for Complex Cardiac Patients

    PubMed Central

    2016-01-01

    Background: In patients with major comorbidities undergoing complex cardiothoracic surgery, incision management is critical. This retrospective review evaluated negative pressure over closed sternal incisions in cardiac patients with multiple comorbidities within 30 days post-median sternotomy. Methods: Records of post-sternotomy patients treated with Prevena™ Incision Management System (KCI, an Acelity company, San Antonio, TX), a closed incision negative pressure therapy (ciNPT), were reviewed from September 2010 through September 2014. Data collected included demographics, major comorbidities, types of surgery, relevant medical history, incision length, therapy duration, time to follow-up, and incision complications. Descriptive statistics were computed for continuous variables, frequency, and percentages for categorical variables. Results: Twenty-seven patients were treated with ciNPT between September 2010 and September 2014. The mean patient age was 62.5 (SD 7.9), and the mean body mass index (BMI) was 38.5 (SD 4.4) kg/m2. Risk factors included obesity (BMI ≥ 30 kg/m2, 27/27; 100%), diabetes (25/27; 92.6%), hypertension (16/27; 59.3%), and 20/27 patients (74%) had ≥ 5 comorbidities. Mean ciNPT duration was 5.6 (SD 0.9) days. Within 30 days post-surgery, 21/27 (77.8%) patients had intact incisions with good reapproximation. Two patients experienced minor dehiscences; four cases of superficial cellulitis were treated and resolved. One patient with a dehiscence was readmitted for intravenous antibiotics and five patients were managed successfully with antibiotics as outpatients. All patients had intact incisions with good skin approximation at final follow-up. Conclusions: In this retrospective study of post-sternotomy patients at high risk of developing complications, ciNPT over closed sternal incisions resulted in favorable outcomes within 30 days of surgery. PMID:27026831

  4. Small Incision Lenticule Extraction for Postkeratoplasty Myopia and Astigmatism

    PubMed Central

    Ibrahim, Osama; Shehata, Kitty; Abdalla, Moones F.

    2016-01-01

    Purpose. To evaluate the visual and refractive outcomes after small incision lenticule extraction (SMILE) for treating myopia and myopic astigmatism after penetrating keratoplasty (PKP). Design. Case-series. Methods. Ten eyes of 10 patients with previous PKP and residual myopic astigmatism for whom pentacam imaging and thickness measurements were acceptable for laser vision correction. Manifest refraction (MR), uncorrected distance visual acuity (UDVA), and corrected distance visual acuity (CDVA) were obtained preoperatively and one day, one week, and one, 3, and 6 months postoperatively. Cases were operated on the VisuMax® femtosecond laser platform with 500 kHz repetition rate. Results. The mean correction ratio for spherical errors was 0.84 ± 0.19 D and for the mean refractive spherical equivalent (MRSE) was 0.79 ± 0.13 D. Vector analysis showed a mean astigmatism reduction at the intended axis of 67 ± 25.25%, a correction index of 0.81 ± 0.21, and an overall mean percentage of success of astigmatism surgery of 53 ± 37.9%. The postoperative MRSE was stable throughout the 6-month follow-up period. The efficacy index was 0.93 and the safety index was 1.12. Conclusion. SMILE for correction of post-PKP myopia and astigmatism is effective, safe, and stable with moderate accuracy and predictability. Centration of the treatment within the grafts was easily performed. PMID:27446606

  5. Caesarean in mare by Marcenac incision under local anaesthesia

    PubMed Central

    Ninu, A. R; Saxena, A. C; Sivanarayanan, T. B; Remya, V; Binsila, B. K; Maiti, S. K; Zama, M. M. S

    2015-01-01

    A nulliparous non-descript mare was presented with a complaint of dystocia. The mare was recumbent and physical examination revealed that the animal was in shock. There was no straining and foetal forelimbs were visible outside the vulva. The foetus was dead as there was no pedal reflex. Vaginal examination revealed anterior presentation with dorso-sacral position and rigid lateral head deviation. Pre-operatively, the mare was given 5 ml Tetanus toxoid and 3 g Ceftriaxone as intramuscular injection, and 5 ml Dexamethasone in 15 L of 5% Dextrose Normal Saline (DNS) as intravenous (i/v) infusion. As pelvic space was inadequate and the mal posture was not correctable, manual correction or foetotomy could not be attempted and therefore caesarean section was planned. Condition of the animal warranted the use of local anaesthetic infiltration instead of general anesthesia. Post-operative care included intravenous fluids, anti-inflammatory/analgesics and daily antiseptic dressing. The owner reported uneventful recovery. The authors would like to conclude the case as a rare emergency caesarean in equine where the surgery was done with animal in lateral recumbency employing a Marcenac incision under local anaesthesia. PMID:27175164

  6. Computer guidance system for single-incision bimanual robotic surgery.

    PubMed

    Carbone, Marina; Turini, Giuseppe; Petroni, Gianluigi; Niccolini, Marta; Menciassi, Arianna; Ferrari, Mauro; Mosca, Franco; Ferrari, Vincenzo

    2012-01-01

    The evolution of surgical robotics is following the progress of developments in Minimally Invasive Surgery (MIS), which is moving towards Single-Incision Laparoscopic Surgery (SILS) procedures. The complexity of these techniques has favored the introduction of robotic surgical systems. New bimanual robots, which are completely inserted into the patient's body, have been proposed in order to enhance the surgical gesture in SILS procedures. However, the limited laparoscopic view and the focus on the end-effectors, together with the use of complex robotic devices inside the patient's abdomen, may lead to unexpected collisions, e.g., between the surrounding anatomical organs not involved in the intervention and the surgical robot. This paper describes a computer guidance system, based on patient-specific data, designed to provide intraoperative navigation and assistance in SILS robotic interventions. The navigator has been tested in simulations of some of the surgical tasks involved in a cholecystectomy, using a synthetic anthropomorphic mannequin. The results demonstrate the usability and efficacy of the navigation system, underlining the importance of avoiding unwanted collisions between the robot arms and critical organs. The proposed computer guidance software is able to integrate any bimanual surgical robot design. PMID:22687053

  7. Experience of single-incision laparoscopy in children

    PubMed Central

    Ming, Yung Ching; Yang, Wendy; Chen, Jeng Chang; Chang, Pei Yeh; Lai, Jin Yao

    2016-01-01

    CONTEXT: Laparoscopic surgery is commonly used for the treatment of many pediatric surgical diseases at our department. Single-incision laparoscopic surgery (SILS) is well-known for its cosmetic benefit. We, hereby, present our experience of SILS and evaluate its efficacy. MATERIALS AND METHODS: From July 2012 to June 2014, 78 patients aged less than 18 years who underwent SILS were retrospectively evaluated. There were 44 males and 34 females, with a mean age of 10.3 years. The procedures included appendectomy (n = 64), reduction of intussusception (n = 8), removal of an intestinal foreign body (n = 3), and Meckel's diverticulectomy (n = 3). We compared the patients who underwent SILS with those who underwent conventional laparoscopic surgery (CLS), regarding these procedures. The parameters for analysis included the patient's demographic data, surgical indication, complications, operative time, and length of hospital stay. CONCLUSION: SILS is comparable to CLS regarding two major procedures, namely, appendectomy and reduction of intussusception. There were no significant differences between the two groups regarding the patients' demographic data, complications, and length of hospital stay. According to our experience of SILS, it could be a feasible and safe procedure for the treatment of various pediatric surgical diseases. However, large prospective randomized studies are needed to identify the differences between SIL and CLS. PMID:27279396

  8. Surface electromyography analysis of blepharoptosis correction by transconjunctival incisions.

    PubMed

    Tu, Lung-Chen; Wu, Ming-Chya; Chu, Hsueh-Liang; Chiang, Yi-Pin; Kuo, Chih-Lin; Li, Hsing-Yuan; Chang, Chia-Ching

    2016-06-01

    Upper eyelid movement depends on the antagonistic actions of orbicularis oculi muscle and levator aponeurosis. Blepharoptosis is an abnormal drooping of upper eyelid margin with the eye in primary position of gaze. Transconjunctival incisions for upper eyelid ptosis correction have been a well-developed technique. Conventional prognosis however depends on clinical observations and lacks of quantitatively analysis for the eyelid muscle controlling. This study examines the possibility of using the assessments of temporal correlation in surface electromyography (SEMG) as a quantitative description for the change of muscle controlling after operation. Eyelid SEMG was measured from patients with blepharoptosis preoperatively and postoperatively, as well as, for comparative study, from young and aged normal subjects. The data were analyzed using the detrended fluctuation analysis method. The results show that the temporal correlation of the SEMG signals can be characterized by two indices associated with the correlation properties in short and long time scales demarcated at 3ms, corresponding to the time scale of neural response. Aging causes degradation of the correlation properties at both time scales, and patient group likely possess more serious correlation degradation in long-time regime which was improved moderately by the ptosis corrections. We propose that the temporal correlation in SEMG signals may be regarded as an indicator for evaluating the performance of eyelid muscle controlling in postoperative recovery. PMID:26990614

  9. Small incision cataract surgery: Complications and mini-review.

    PubMed

    Gogate, Parikshit M

    2009-01-01

    This article reviews the literature on manual small incision cataract surgery (MSICS) and its complications. Various articles on MSICS published in indexed journals were reviewed, as well as the sections on complications of MSICS. The Pubmed search engine on the Internet was used to find out articles published since 1985 on MSICS in any language in indexed journals. Books published by Indian authors and the website of Indian Journal of Ophthalmology were also referred to. MSICS has become very popular technique of cataract surgery in India, and it is often used as an alternative to phacoemulsification. Studies on its efficacy and safety for cataract surgery show that, being a variant of extracapsular cataract surgery, MSICS also has similar intraoperative and postoperative complications. The considerable handling inside the anterior chamber during nucleus delivery increase the chances of iris injury, striate keratitis, and posterior capsular rupture. The surgeon has to be extra careful in the construction of the scleral tunnel and to achieve a good capsulorrhexis. Postoperative inflammation and corneal edema are rare if surgeons have the expertise and patience. The final astigmatism is less than that in the extracapsular cataract surgery and almost comparable to that in phacoemulsification. There is, however, a concern of posterior capsular opacification in the long term, which needs to be addressed. Although MSICS demands skill and patience from the cataract surgeon, it is a safe, effective, and economical alternative to competing techniques and can be the answer to tackle the large backlog of blindness due to cataract. PMID:19075410

  10. Small Incision Lenticule Extraction for Postkeratoplasty Myopia and Astigmatism.

    PubMed

    Massoud, Tamer H; Ibrahim, Osama; Shehata, Kitty; Abdalla, Moones F

    2016-01-01

    Purpose. To evaluate the visual and refractive outcomes after small incision lenticule extraction (SMILE) for treating myopia and myopic astigmatism after penetrating keratoplasty (PKP). Design. Case-series. Methods. Ten eyes of 10 patients with previous PKP and residual myopic astigmatism for whom pentacam imaging and thickness measurements were acceptable for laser vision correction. Manifest refraction (MR), uncorrected distance visual acuity (UDVA), and corrected distance visual acuity (CDVA) were obtained preoperatively and one day, one week, and one, 3, and 6 months postoperatively. Cases were operated on the VisuMax® femtosecond laser platform with 500 kHz repetition rate. Results. The mean correction ratio for spherical errors was 0.84 ± 0.19 D and for the mean refractive spherical equivalent (MRSE) was 0.79 ± 0.13 D. Vector analysis showed a mean astigmatism reduction at the intended axis of 67 ± 25.25%, a correction index of 0.81 ± 0.21, and an overall mean percentage of success of astigmatism surgery of 53 ± 37.9%. The postoperative MRSE was stable throughout the 6-month follow-up period. The efficacy index was 0.93 and the safety index was 1.12. Conclusion. SMILE for correction of post-PKP myopia and astigmatism is effective, safe, and stable with moderate accuracy and predictability. Centration of the treatment within the grafts was easily performed. PMID:27446606

  11. Knife-edge test for characterization of subnanometer deformations in micro-optical surfaces

    NASA Astrophysics Data System (ADS)

    Zamkotsian, Frederic; Dohlen, Kjetil; Lanzoni, Patrick; Mazzanti, Silvio; Michel, Marie-Laurence; Buat, Veronique; Burgarella, Denis

    1999-11-01

    Development of accurate surface characterization methods is essential for testing micro-optical components, such as micro- opto-electro-mechanical systems (MOEMS), for use in complex optical systems. We consider using an array of 16 micrometer- wide micro-mirrors as programmable slits for astronomical multi-object spectroscopy, and propose a new method based upon Foucault's knife-edge test to characterize local surface deformations of individual micro-mirrors. By measuring local slopes, the surface shape of each mirror in a micro-mirror array has been reconstructed with a sub-nanometer accuracy. In addition to low-order deformation (tilt, curvature, astigmatism), each mirror is seen to be palm-tree shaped. We have checked the validity of our knife-edge test by the micro- characterization of a conventional spherical mirror.

  12. Cutting a Drop of Water Pinned by Wire Loops Using a Superhydrophobic Surface and Knife

    PubMed Central

    Yanashima, Ryan; García, Antonio A.; Aldridge, James; Weiss, Noah; Hayes, Mark A.; Andrews, James H.

    2012-01-01

    A water drop on a superhydrophobic surface that is pinned by wire loops can be reproducibly cut without formation of satellite droplets. Drops placed on low-density polyethylene surfaces and Teflon-coated glass slides were cut with superhydrophobic knives of low-density polyethylene and treated copper or zinc sheets, respectively. Distortion of drop shape by the superhydrophobic knife enables a clean break. The driving force for droplet formation arises from the lower surface free energy for two separate drops, and it is modeled as a 2-D system. An estimate of the free energy change serves to guide when droplets will form based on the variation of drop volume, loop spacing and knife depth. Combining the cutting process with an electrofocusing driving force could enable a reproducible biomolecular separation without troubling satellite drop formation. PMID:23029297

  13. Three-dimensional radiation dosimetry for gamma knife using a gel dosimeter

    NASA Astrophysics Data System (ADS)

    Hussain, Kazi Muazzam

    The use of three-dimensional radiation dosimetry has been limited. With the use of water phantoms and ionization chambers, it has been possible to determine three dimensional dose distributions on a gross scale for cobalt 60 and linear accelerator sources. This method has been somewhat useful for traditional radiotherapy. There is, however, a need for more precise dosimetry, particularly with stereotactic radiosurgery. Most gamma knife facilities use either thermoluminescant dosimetry or film, neither of which provides three dimensional dose distributions. To overcome this limitation, we have developed a gel dosimetry system that relies on the production of a ferric ion-xylenol orange colored complex. This work demonstrates the use of laser light and a detector to quantify radiation-induced colorimetric changes in absorbance for the gel dosimeter. The absorbance has been reconstructed by the back projection technique to demonstrate the applicability of the gel dosimeter to gamma knife 3D-dose distributions.

  14. Rapid late pleistocene incision of Atlantic passive-margin river gorges

    USGS Publications Warehouse

    Reusser, L.J.; Bierman, P.R.; Pavich, M.J.; Zen, E.-A.; Larsen, J.; Finkel, R.

    2004-01-01

    The direct and secondary effects of rapidly changing climate caused large rivers draining the Atlantic passive margin to incise quickly into bedrock beginning about 35,000 years ago. Measured in samples from bedrock fluvial terraces, 10-beryllium shows that both the Susquehanna and Potomac Rivers incised 10- to 20-meter-deep gorges along steep, convex lower reaches during the last glacial cycle. This short-lived pulse of unusually rapid downcutting ended by 13,000 to 14,000 years ago. The timing and rate of downcutting are similar on the glaciated Susquehanna and unglaciated Potomac Rivers, indicating that regional changes, not simply glacial melt-water, initiated incision.

  15. Rapid Late Pleistocene Incision of Atlantic Passive-Margin River Gorges

    NASA Astrophysics Data System (ADS)

    Reusser, Luke J.; Bierman, Paul R.; Pavich, Milan J.; Zen, E.-an; Larsen, Jennifer; Finkel, Robert

    2004-07-01

    The direct and secondary effects of rapidly changing climate caused large rivers draining the Atlantic passive margin to incise quickly into bedrock beginning about 35,000 years ago. Measured in samples from bedrock fluvial terraces, 10-beryllium shows that both the Susquehanna and Potomac Rivers incised 10- to 20-meter-deep gorges along steep, convex lower reaches during the last glacial cycle. This short-lived pulse of unusually rapid downcutting ended by 13,000 to 14,000 years ago. The timing and rate of downcutting are similar on the glaciated Susquehanna and unglaciated Potomac Rivers, indicating that regional changes, not simply glacial meltwater, initiated incision.

  16. Towards achieving small-incision cataract surgery 99.8% of the time.

    PubMed

    Thomas, R; Kuriakose, T; George, R

    2000-06-01

    A surgical approach designed to reliably attain the modern goal of small incision cataract surgery 99.8% of the time is described. Phacoemulsification as well as a manual small incision technique is utilised to achieve the desired outcome as often as possible and for all types of cataracts. The logic, and required surgical steps are described and illustrated. This surgical technique allows the advantages of small incision surgery to be reliably achieved. The method is flexible and allows decisions and steps to be modified depending on the skill and comfort zone of the individual surgeon. PMID:11116514

  17. TH-A-9A-06: Inverse Planning of Gamma Knife Radiosurgery Using Natural Physical Models

    SciTech Connect

    Riofrio, D; Ma, L; Zhou, J; Luan, S

    2014-06-15

    Purpose: Treatment-planning systems rely on computer intensive optimization algorithms in order to provide radiation dose localization. We are investigating a new optimization paradigm based on natural physical modeling and simulations, which tend to evolve in time and find the minimum energy state. In our research, we aim to match physical models with radiation therapy inverse planning problems, where the minimum energy state coincides with the optimal solution. As a prototype study, we have modeled the inverse planning of Gamma Knife radiosurgery using the dynamic interactions between charged particles and demonstrate the potential of the paradigm. Methods: For inverse planning of Gamma Knife radiosurgery: (1) positive charges are uniformly placed on the surface of tumors and critical structures. (2) The Gamma Knife dose kernels of 4mm, 8mm and 16mm radii are modeled as geometric objects with variable charges. (3) The number of shots per each kernel radii is obtained by solving a constrained integer-linear problem. (4) The shots are placed into the tumor volume and move under electrostatic forces. The simulation is performed until internal forces are zero or maximum iterations are reached. (5) Finally, non-negative least squares (NNLS) is used to calculate the beam-on times for each shot. Results: A 3D C-shaped tumor surrounding a spherical critical structure was used for testing the new optimization paradigm. These tests showed that charges spread out evenly covering the tumor while keeping distance from the critical structure, resulting in a high quality plan. Conclusion: We have developed a new paradigm for dose optimization based on the simulation of physical models. As prototype studies, we applied electrostatic models to Gamma Knife radiosurgery and demonstrated the potential of the new paradigm. Further research and fine-tuning of the model are underway. NSF CBET-0853157.

  18. An intermediate term benefits and complications of gamma knife surgery in management of glomus jugulare tumor.

    PubMed

    Hafez, Raef F A; Morgan, Magad S; Fahmy, Osama M

    2016-01-01

    Glomus tumors are rare skull base slow-growing, hypervascular neoplasms that frequently involve critical neurovascular structures, and delay in diagnosis is frequent. Surgical removal is rarely radical and is usually associated with morbidity or mortality. Gamma knife surgery (GKS) has gained an increasing dependable role in the management of glomus jugulare tumors, with high rate of tumor growth control, preserving or improving clinical status and with limited complications. This study aims to evaluate intermediate term benefits and complications of gamma knife surgery in management of twenty-two patients bearing growing glomus jugulare tumors at the International Medical Center (IMC), Cairo, Egypt, between 2005 and 2011. The mean follow-up period was 56 months (range 36-108 months); there were 3 males, 19 females; mean age was 43.6 years; 15 patients had GKS as the primary treatment; 2 patients had surgical residuals; 2 had previous radiation therapy; and 3 previously underwent endovascular embolization. The average tumor volume was 7.26 cm3, and the mean marginal dose was 14.7 Gy. Post gamma knife surgery through the follow-up period neurological status was improved in 12 patients, 7 showed stable clinical condition and 3 patients developed new moderate deficits. Tumor volume post GKS was unchanged in 13 patients, decreased in 8, and showed tumor regrowth in 1 patient. Tumor progression-free survival in our studied patients was 95.5% at 5 and 7 years of the follow-up period post GKS. Gamma knife surgery could be used safely and effectively with limited complications as a primary management tool in the treatment of glomus jugulare tumors controlling tumor growth with preserving or improving clinical status especially those who do not have significant cranial or cervical extension, elderly, and surgically unfit patients; moreover, it is safe and highly effective as adjuvant therapy as well. PMID:26879488

  19. [CyberKnife robotic stereotactic radiotherapy: technical aspects and medical indications].

    PubMed

    Bondiau, P-Y; Bénézery, K; Beckendorf, V; Peiffert, D; Gérard, J-P; Mirabel, X; Noël, A; Marchesi, V; Lacornerie, T; Dubus, F; Sarrazin, T; Herault, J; Marcié, S; Angellier, G; Lartigau, E

    2007-11-01

    In 2006, 3 sites have been selected by the Institut national of cancer (Lille, Nancy et Nice) to evaluate a radiotherapy robot, the CyberKnife. This machine, able to track mobile tumours in real time, gives new possibilities in the field of extra cranial stereotactic radiotherapy. Functionalities and medico economical issues of the machine will be evaluated during 2 years on the 3 sites. PMID:18029216

  20. Differential phase microscope and micro-tomography with a Foucault knife-edge scanning filter

    NASA Astrophysics Data System (ADS)

    Watanabe, N.; Hashizume, J.; Goto, M.; Yamaguchi, M.; Tsujimura, T.; Aoki, S.

    2013-10-01

    An x-ray differential phase microscope with a Foucault knife-edge scanning filter was set up at the bending magnet source BL3C, Photon Factory. A reconstructed phase profile from the differential phase image of an aluminium wire at 5.36 keV was fairly good agreement with the numerical simulation. Phase tomography of a biological specimen, such as an Artemia cyst, could be successfully demonstrated.

  1. Simulation of DNA Supercoil Relaxation.

    PubMed

    Ivenso, Ikenna D; Lillian, Todd D

    2016-05-24

    Several recent single-molecule experiments observe the response of supercoiled DNA to nicking endonucleases and topoisomerases. Typically in these experiments, indirect measurements of supercoil relaxation are obtained by observing the motion of a large micron-sized bead. The bead, which also serves to manipulate DNA, experiences significant drag and thereby obscures supercoil dynamics. Here we employ our discrete wormlike chain model to bypass experimental limitations and simulate the dynamic response of supercoiled DNA to a single strand nick. From our simulations, we make three major observations. First, extension is a poor dynamic measure of supercoil relaxation; in fact, the linking number relaxes so fast that it cannot have much impact on extension. Second, the rate of linking number relaxation depends upon its initial partitioning into twist and writhe as determined by tension. Third, the extensional response strongly depends upon the initial position of plectonemes. PMID:27224483

  2. CyberKnife therapy of 24 multiple brain metastases from lung cancer: A case report

    PubMed Central

    YANG, GUIQING; WANG, YISHAN; WANG, YUANYUAN; LIN, SIXIANG; SUN, DONGNING

    2013-01-01

    Brain metastasis is a significant cause of morbidity and mortality and a critical complication of non-central nervous system primary carcinoma. The present study describes the clinical case of a 46-year-old male with lung cancer and life-threatening brain metastases. The patient was diagnosed with lung cancer with a clinical stage of T2N0M1 (stage IV). Six months after the initial diagnosis and administration of conformal radiotherapy combined with three cycles of chemotherapy, an enhanced computed tomography (CT) scan of the brain revealed abnormalities with double-dosing of intravenous contrast. The CT scan identified >24 lesions scattered in the whole brain. The patient was treated with three-fraction Cyberknife radiotherapy at 22 Gy, delivered to the brain metastases at the Center for Tumor Treatment of People’s Liberation Army 107th Hospital. Following CyberKnife therapy, a CT scan of the brain revealed that most of the tumors had disappeared with almost no residual traces. The stereotactic radiosurgery (SRS) conducted using CyberKnife, an image-guided frameless robotic technology for whole-body radiosurgery, had produced a marked response. The present case report demonstrates that CyberKnife therapy plays a significant role in the management of multiple meta-static brain tumors. PMID:24137362

  3. Near-field ray calculation for multiple knife-edge diffraction

    NASA Astrophysics Data System (ADS)

    Whitteker, J. H.

    1984-08-01

    A new ray approximation for calculating the diffraction attenuation due to several knife edges takes into account the wave-normal direction of the diffracted wave in the near field, using the Fresnel approximation. The theory is intended for terrestrial radio wave propagation and for other situations where obstructions are nearly collinear. The far-field form of the wave is adopted, as in asymptotic theories, but the focal line of the diffracted ray pencil coincides with the diffracting edge only in the limit as the field point moves deep into the geometric shadow. In general, the ray passes above the diffracting edges rather than through them. The theory is developed for knife edges only, but may be adaptable to other shapes of diffracting obstruction. In the examples given, the calculated attenuations are much more accurate than if the far-field approximation is assumed, but less accurate than if the complete Fresnel integration is done. In a comparison with the complete Fresnel integration, the difference turns out to be less than 1 dB for five or fewer knife edges.

  4. Selective source blocking for Gamma Knife radiosurgery of trigeminal neuralgia based on analytical dose modelling.

    PubMed

    Li, Kaile; Ma, Lijun

    2004-08-01

    We have developed an automatic critical region shielding (ACRS) algorithm for Gamma Knife radiosurgery of trigeminal neuralgia. The algorithm selectively blocks 201 Gamma Knife sources to minimize the dose to the brainstem while irradiating the root entry area of the trigeminal nerve with 70-90 Gy. An independent dose model was developed to implement the algorithm. The accuracy of the dose model was tested and validated via comparison with the Leksell GammaPlan (LGP) calculations. Agreements of 3% or 3 mm in isodose distributions were found for both single-shot and multiple-shot treatment plans. After the optimized blocking patterns are obtained via the independent dose model, they are imported into the LGP for final dose calculations and treatment planning analyses. We found that the use of a moderate number of source plugs (30-50 plugs) significantly lowered (approximately 40%) the dose to the brainstem for trigeminal neuralgia treatments. Considering the small effort involved in using these plugs, we recommend source blocking for all trigeminal neuralgia treatments with Gamma Knife radiosurgery. PMID:15379025

  5. An investigation of eye lens dose for gamma knife treatments of trigeminal neuralgia.

    PubMed

    Ma, L; Chin, L; Sarfaraz, M; Shepard, D; Yu, C

    2000-01-01

    Stereotactic Gamma Knife radiosurgery has been widely used for treating trigeminal neuralgia (TN). A single large fractional dose of 7000 to 9000 cGy is commonly prescribed as the maximum dose for these treatments. For this reason, if a small percentage of the prescribed dose such as 2-3% scattered to the eye, it could reach or even exceed the tolerance dose of the lens. For several TN cases, we found that the Leksell Gamma Plan system calculates the lens dose about 0.5-2% of the maximum dose independent of the use of eye shielding. These dose values are significantly high and it motivated us to investigate the lens dose for the TN patients treated with stereotactic Gamma Knife radiosurgery. Phantom studies and in vivo dosimetry measurements were carried out for six patients treated at our institution. The average dose to the lens ipsilateral to the treated nerve was measured to be 7.7+/-0.6 cGy. Based on the biological model of Lyman and Emami [Int. J. Radiat. Oncol. Biol. Phys. 21, 109-122 (1991)], the probability of the lens complication (cataract) was determined to be 0.1%. Our findings suggest that few TN patients would develop cataracts after receiving Gamma Knife radiosurgery. PMID:11674826

  6. Electric Field Screening by the Proximity of Two Knife-Edge Field Emitters of Finite Width

    NASA Astrophysics Data System (ADS)

    Wong, P.; Tang, W.; Lau, Y. Y.; Hoff, B.

    2015-11-01

    Field emitter arrays have the potential to provide high current density, low voltage operation, and high pulse repetition for radar and communication. It is well known that packing density of the field emitter arrays significantly affect the emission current. Previously we calculated analytically the electric field profile of two-dimensional knife-edge cathodes with arbitrary separation by using a Schwarz-Christoffel transformation. Here we extend this previous work to include the finite width of two identical emitters. From the electric field profile, the field enhancement factor, thereby the severity of the electric field screening, are determined. It is found that for two identical emitters with finite width, the magnitude of the electric field on the knife-edge cathodes depends strongly on the ratio h / a and h / r , where h is the height of the knife-edge cathode, 2a is the distance between the cathodes, and 2 r represents their width. Particle-in-cell simulations are performed to compare with the analytical results on the emission current distribution. P. Y. Wong was supported by a Directed Energy Summer Scholar internship at Air Force Research Laboratory, Kirtland AFB, and by AFRL Award No. FA9451-14-1-0374.

  7. A simple method of independent treatment time verification in gamma knife radiosurgery using integral dose

    SciTech Connect

    Jin Jianyue; Drzymala, Robert; Li Zuofeng

    2004-12-01

    The purpose of this study is to develop a simple independent dose calculation method to verify treatment plans for Leksell Gamma Knife radiosurgery. Our approach uses the total integral dose within the skull as an end point for comparison. The total integral dose is computed using a spreadsheet and is compared to that obtained from Leksell GammaPlan registered . It is calculated as the sum of the integral doses of 201 beams, each passing through a cylindrical volume. The average length of the cylinders is estimated from the Skull-Scaler measurement data taken before treatment. Correction factors are applied to the length of the cylinder depending on the location of a shot in the skull. The radius of the cylinder corresponds to the collimator aperture of the helmet, with a correction factor for the beam penumbra and scattering. We have tested our simple spreadsheet program using treatment plans of 40 patients treated with Gamma Knife registered in our center. These patients differ in geometry, size, lesion locations, collimator helmet, and treatment complexities. Results show that differences between our calculations and treatment planning results are typically within {+-}3%, with a maximum difference of {+-}3.8%. We demonstrate that our spreadsheet program is a convenient and effective independent method to verify treatment planning irradiation times prior to implementation of Gamma Knife radiosurgery.

  8. Bulk flow coupled to a viscous interfacial film sheared by a rotating knife edge

    NASA Astrophysics Data System (ADS)

    Raghunandan, Aditya; Rasheed, Fayaz; Hirsa, Amir; Lopez, Juan

    2015-11-01

    The measurement of the interfacial properties of highly viscous biofilms, such as DPPC (the primary component of lung surfactant), present on the surface of liquids (bulk phase) continues to attract significant attention. Most measurement techniques rely on shearing the interfacial film and quantifying its viscous response in terms of a surface (excess) viscosity at the air-liquid interface. The knife edge viscometer offers a significant advantage over other approaches used to study highly viscous films as the film is directly sheared by a rotating knife edge in direct contact with the film. However, accurately quantifying the viscous response is non-trivial and involves accounting for the coupled interfacial and bulk phase flows. Here, we examine the nature of the viscous response of water insoluble DPPC films sheared in a knife edge viscometer over a range of surface packing, and its influence on the strength of the coupled bulk flow. Experimental results, obtained via Particle Image Velocimetry in the bulk and at the surface (via Brewster Angle Microscopy), are compared with numerical flow predictions to quantify the coupling across hydrodynamic flow regimes, from the Stokes flow limit to regimes where flow inertia is significant. Supported by NNX13AQ22G, National Aeronautics and Space Administration.

  9. Stereotactic radiosurgery of prostate cancer - dose distribution for VMAT and CyberKnife techniques

    NASA Astrophysics Data System (ADS)

    Ślosarek, Krzysztof; Osewski, Wojciech; Grządziel, Aleksandra; Stąpór-Fudzińska, Małgorzata; Szlag, Marta

    2016-06-01

    New capabilities of biomedical accelerators allow for very precise depositing of the radiation dose and imaging verification during the therapy. In addition, computer algorithms calculating dose distributions are taking into account the increasing number of physical effects. Therefore, administration of high dose fractionation, which is consistent with radiobiology used in oncology, becomes safer and safer. Stereotactic radiosurgery (SRS), which is very precise irradiation with high dose fractionation is increasingly widespread use in radiotherapy of prostate cancer. For this purpose different biomedical accelerators are used. The aim of this study is to compare dose distributions for two techniques: VMAT and CyberKnife. Statistical analysis was performed for the two groups of patients treated by VMAT technique (25 patients), and CyberKnife technique (15 patients). The analysis shows that the dose distributions are comparable, both in the treated area (prostate) and in the critical organs (rectum, urinary bladder, femoral heads). The results show that stereotactic radiosurgery of prostate cancer can be carried out on CyberKnife accelerator as well as on the classical accelerator with the use of VMAT technique.

  10. Statistical bounds and maximum likelihood performance for shot noise limited knife-edge modeled stellar occultation

    NASA Astrophysics Data System (ADS)

    McNicholl, Patrick J.; Crabtree, Peter N.

    2014-09-01

    Applications of stellar occultation by solar system objects have a long history for determining universal time, detecting binary stars, and providing estimates of sizes of asteroids and minor planets. More recently, extension of this last application has been proposed as a technique to provide information (if not complete shadow images) of geosynchronous satellites. Diffraction has long been recognized as a source of distortion for such occultation measurements, and models subsequently developed to compensate for this degradation. Typically these models employ a knife-edge assumption for the obscuring body. In this preliminary study, we report on the fundamental limitations of knife-edge position estimates due to shot noise in an otherwise idealized measurement. In particular, we address the statistical bounds, both Cramér- Rao and Hammersley-Chapman-Robbins, on the uncertainty in the knife-edge position measurement, as well as the performance of the maximum-likelihood estimator. Results are presented as a function of both stellar magnitude and sensor passband; the limiting case of infinite resolving power is also explored.

  11. Experimental and computational studies on Coanda nozzle flow for the air knife application

    NASA Astrophysics Data System (ADS)

    Kwon, Soon-Bum; Lee, Dong-Won; Kwon, Young-Doo

    2007-05-01

    To control the film thickness of zinc in the process of continuous hot-dip galvanizing, it is known from the early days that the gas wiping through an air knife is the most effective one. The gas wiping using in galvanizing process brings about a problem of splashing from the strip edge for a certain high speed of coating. So, in the present study, the effects of the deflection angle of Coanda nozzle on jet structure and the distribution of impinging pressure at the plate surface are investigated numerically and experimentally. In numerical analysis, the governing equations consisted of three-dimensional time dependent full Navier-Stokes equations, standard k-ɛ turbulence model to solve turbulent stress and so on are employed. In experiment, 16 channel pressure scanning valve and 3-axis auto traversing unit are used to measure the impinging pressure at the strip surface. As a result, it is found that the smaller the deflection angle for the same nozzle slit of air knife is, the larger the impinging pressure is. To reduce the size of separation bubble and to enhance the cutting ability, it is recommendable to use an air knife with the Coanda nozzle.

  12. Retrospective evaluation of CTV to PTV margins using CyberKnife in patients with thoracic tumors.

    PubMed

    Floriano, Alejandro; García, Rafael; Moreno, Ramon; Sánchez-Reyes, Alberto

    2014-01-01

    The objectives of this study were to estimate global uncertainty for patients with thoracic tumors treated in our center using the CyberKnife VSI after placement of fiducial markers and to compare our findings with the standard CTV to PTV margins used to date. Datasets for 16 patients (54 fractions) treated with the CyberKnife and the Synchrony Respiratory Tracking System were analyzed retrospectively based on CT planning, tracking information, and movement data generated and saved in the logs files by the system. For each patient, we analyzed all the main uncertainty sources and assigned a value. We also calculated an expanded global uncertainty to ensure a robust estimation of global uncertainty and to enable us to determine the position of 95% of the CTV points with a 95% confidence level during treatment. Based on our estimation of global uncertainty and compared with our general mar- gin criterion (5 mm in all three directions: superior/inferior [SI], anterior/posterior [AP], and lateral [LAT]), 100% were adequately covered in the LAT direction, as were 94% and 94% in the SI and AP directions. We retrospectively analyzed the main sources of uncertainty in the CyberKnife process patient by patient. This individualized approach enabled us to estimate margins for patients with thoracic tumors treated in our unit and compare the results with our standard 5 mm margin.  PMID:25493508

  13. Analysis of clinical efficacy of CyberKnife® treatment for locally advanced pancreatic cancer

    PubMed Central

    Song, Yongchun; Yuan, Zhiyong; Li, Fengtong; Dong, Yang; Zhuang, Hongqing; Wang, Jingsheng; Chen, Huaming; Wang, Ping

    2015-01-01

    Objective To evaluate the efficacy and safety of CyberKnife® treatment for locally-advanced pancreatic cancer (LAPC). Methods The efficacy of CyberKnife® treatment was analyzed in 59 LAPC patients treated between October 2006 and September 2014. The median tumor volume was 27.1 mL (13.0–125.145 mL). The median prescribed dose was 45 Gy (35–50 Gy), delivered in 5 fractions (3–8 fractions). The overall survival (OS) rates and freedom from local progression (FFLP) rates were estimated using the Kaplan–Meier survival curve. Results The median follow-up for all patients was 10.9 months (3.2–48.7 months) and 15.6 months (3.9–37.6 months) among surviving patients. The median OS was 12.5 months, and the 1-year and 2-year survival rates were 53.9% and 35.1%, respectively. The 1-year FFLP rate was 90.8% based on the computed tomography (CT) evaluation. Grade 1–2 acute and late-stage gastrointestinal (GI) reactions were observed in 61% of the patients. One patient experienced grade 3 toxicity. Conclusion Excellent clinical efficacy was obtained after treatment of LAPC using CyberKnife®, with minimal toxicity. PMID:26109866

  14. Stereotactic radiosurgery of the brain using the first United States 201 cobalt-60 source gamma knife

    SciTech Connect

    Lunsford, L.D.; Flickinger, J.; Lindner, G.; Maitz, A.

    1989-02-01

    The first United States 201 cobalt-60 source gamma knife for stereotactic radiosurgery of brain tumors and arteriovenous malformations became operational at the University of Pittsburgh on August 14, 1987. Four and one-half years of intensive planning, regulatory agency review, and analysis of published results preceded the first radiosurgical procedure. Installation of this 18,000-kg device and loading of the 201 cobalt-60 sources posed major challenges in engineering, architecture, and radiophysics. In the first 4 months of operation, we treated 52 patients (29 with arteriovenous malformations, 19 with extra-axial neoplasms of the skull base, and 4 with intra-axial malignant tumors). Most patients either had lesions considered inoperable or had residual lesions after attempted surgical resection. Neither surgical mortality nor significant morbidity was associated with gamma knife radiosurgery. As compared with treatment by conventional intracranial surgery (craniotomy), the average length of stay for radiosurgery was reduced by 4 to 14 days, and hospital charges were reduced by as much as 65%. Based on both the previously published results of treatment of more than 2,000 patients worldwide and on our initial clinical experience, we believe that gamma knife stereotactic radiosurgery is a therapeutically effective and economically sound alternative to more conventional neurosurgical procedures, in selected cases.

  15. Ribbons of semithin sections: an advanced method with a new type of diamond knife.

    PubMed

    Blumer, Michael J F; Gahleitner, P; Narzt, T; Handl, C; Ruthensteiner, B

    2002-10-15

    Complete series of semithin sections are imperative for 3-D reconstruction, but with traditional microtomy techniques it is difficult and time-consuming to trace stained and labeled structures. In the present study we introduce a method for making and collecting ribbons of semithin sections with a new, commercial available diamond knife (histo-jumbo-diamond knife, Diatome AG, Biel, Switzerland). The special feature of the diamond knife is the large water bath (boat) into which a glass slide can be dipped. The method has distinct advantages and the handling is simple. The resin block is trimmed into a truncated pyramid. Contact glue is applied to the leading face of the pyramid, which makes sections stick together to form a ribbon. Following sectioning, the ribbons are mounted onto glass slides and aligned in parallel. Stretching out and drying the ribbons on a hot plate is the final step of the method. Major advantages of this method are the perfect alignment of sections with identical orientation of structures, the completeness of series, and the significant saving of time. This facilitates tracing of stained and labeled structures, yielding quick 3-D reconstruction. Semithin sections can be cut from 0.5 to 2 micro m and several ribbons can be mounted side by side onto the slide. Two examples are presented to illustrate the advantages of the method. PMID:12351202

  16. Selective source blocking for Gamma Knife radiosurgery of trigeminal neuralgia based on analytical dose modelling

    NASA Astrophysics Data System (ADS)

    Li, Kaile; Ma, Lijun

    2004-08-01

    We have developed an automatic critical region shielding (ACRS) algorithm for Gamma Knife radiosurgery of trigeminal neuralgia. The algorithm selectively blocks 201 Gamma Knife sources to minimize the dose to the brainstem while irradiating the root entry area of the trigeminal nerve with 70-90 Gy. An independent dose model was developed to implement the algorithm. The accuracy of the dose model was tested and validated via comparison with the Leksell GammaPlan (LGP) calculations. Agreements of 3% or 3 mm in isodose distributions were found for both single-shot and multiple-shot treatment plans. After the optimized blocking patterns are obtained via the independent dose model, they are imported into the LGP for final dose calculations and treatment planning analyses. We found that the use of a moderate number of source plugs (30-50 plugs) significantly lowered (~40%) the dose to the brainstem for trigeminal neuralgia treatments. Considering the small effort involved in using these plugs, we recommend source blocking for all trigeminal neuralgia treatments with Gamma Knife radiosurgery.

  17. A technique to sharpen the beam penumbra for Gamma Knife radiosurgery

    NASA Astrophysics Data System (ADS)

    Guerrero, M.; Li, X. Allen; Ma, Lijun

    2003-06-01

    In stereotactic radiosurgery, a narrow beam penumbra is often desired for producing steep dose fall-off between the target volume and adjacent critical structures. Due to limited source sizes and the scattering effects, the physical penumbra of the Gamma Knife (GK) is often restricted to a width of 1-2 mm. In this work, we developed a technique to further reduce the beam penumbra and improve the dose profile for the Gamma Knife delivery. Under this technique, a conic filter is inserted into an individual plug collimator of a GK helmet to flatten the beam profile. Monte Carlo calculations were carried out to simulate the GK geometry of the individual plug collimator and to optimize the physical shapes of the filters. The calculations were performed for a series of filter shapes with different collimator sizes. Our results show that a proper filter significantly reduces the single GK beam penumbra width (defined as the distance from the 90% to 50% isodose lines) by 30-60%. The beam intensity is reduced by about 20-50% when the filter is used. A treatment plan was developed for a trigeminal neuralgia case by commissioning the filtered beam profile for Leksell Gamma Plan (version 5.31). Compared with the conventional treatment plan, a significant improvement was found on the critical structure sparing and on the target dose uniformity. In conclusion, the proposed technique is feasible and effective in sharpening the beam penumbra for Gamma Knife beam profiles.

  18. Quality of life following living donor nephrectomy comparing classical flank incision and anterior vertical mini-incision.

    PubMed

    Jackobs, Steffan; Becker, Thomas; Lück, Rainer; Jäger, Mark D; Nashan, Björn; Gwinner, Wilfried; Schwarz, Anke; Klempnauer, Jürgen; Neipp, Michael

    2005-11-01

    In this study we focused on the quality of life and satisfaction of living kidney donors comparing traditional lumbar (LDN) and mini-incision donor nephrectomy (MIDN). From May 1996 to December 2002, 174 donor nephrectomies including 127 cases of LDN and 47 cases of MIDN were performed. Donors were evaluated using the SF-36 quality-of-life survey as well as a questionnaire dealing with donors' attitude towards kidney donation, financial burdens, pain, cosmetic satisfaction and duration of sick leave. Our donors achieved comparable or even higher scores in all the SF-36 categories in comparison to the general US population. Following MIDN, quality of life tended to be superior compared to that of LDN donors; however, statistical significance was reached only in one of the eight categories. Duration of sick leave following surgery was in favor of MIDN compared to LDN donors. Statistically significant differences favoring MIDN were observed regarding postoperative hospital stay and cosmetic satisfaction. The procedure would be again undergone by 94 of LDN and 97% of MIDN donors. Open-donor nephrectomy is a safe and cost-effective procedure. Introduction of the here-described MIDN has led to comparable or even improved results compared to LDN. PMID:16180026

  19. Dating the incision of the Yangtze River gorge at the First Bend using three-nuclide burial ages

    NASA Astrophysics Data System (ADS)

    McPhillips, Devin; Hoke, Gregory D.; Liu-Zeng, Jing; Bierman, Paul R.; Rood, Dylan H.; Niedermann, Samuel

    2016-01-01

    Incision of the Yangtze River gorge is widely interpreted as evidence for lower crustal flow beneath the southeast margin of the Tibetan Plateau. Previous work focused on the onset of incision, but the duration of incision remains unknown. Here we present cosmogenic nuclide burial ages of sediments collected from caves on the walls of the gorge that show the gorge was incised ~1 km sometime between 18 and 9 Ma. Thereafter, incision slowed substantially. We resolve middle Miocene burial ages by using three nuclides and accounting for in situ muogenic production. This approach explains the absolute concentrations of 10Be, 26Al, and 21Ne, as well as 26Al/10Be and 21Ne/10Be ratios. A declining incision rate challenges existing geodynamic interpretations by suggesting that either (1) surface uplift has ceased immediately south of the plateau margin or (2) gorge incision is not a useful proxy for the timing of surface uplift.

  20. Late Cenozoic Colorado River Incision and Implications for Neogene Uplift of the Colorado Rockies

    NASA Astrophysics Data System (ADS)

    Aslan, A.; Karlstrom, K. E.; Kirby, E.; Heizler, M. T.

    2012-12-01

    Basalt flows and volcanic ashes serve as a datum for calculating post-10 Ma river incision rates in western Colorado. The main picture that emerges from the data is one of regional variability of incision rates, which we hypothesize to reflect differential uplift of the Colorado Rockies during the Neogene. Maximum rates (90-180 m/Ma) and magnitudes (750-1500 m) of river incision are recorded between Grand Mesa and Glenwood Canyon, and in the Flat Tops. Minimum rates (<30 m/Ma) and magnitudes (<250 m) of river incision are associated post-Laramide normal faults within the Browns Park-Sand Wash basin in northwestern Colorado and in Middle Park of north-central Colorado. Differential uplift of the Colorado Rockies during the late Cenozoic can be inferred by comparing incision rates and magnitudes at locations upstream and downstream of knickzones. Along the Colorado River, post-10 Ma incision rates and magnitudes incision remain fairly constant (rates >100 m/Ma; magnitudes >1000 m) from Grand Mesa upstream to Gore Canyon, and then decrease markedly in Middle Park (rates <10 m/Ma; magnitudes <100 m) across the Gore Canyon knickzone. Normal-faulting of ca. 10 Ma deposits in Middle Park shows that incision rate variations partly reflect late Cenozoic faulting. Along the Yampa River, post-10 Ma incision rates and magnitudes are low (rates 15-27 m/Ma; magnitudes < 230 m) immediately upstream of Yampa Canyon, and then increase significantly (rates 96-132 m/Ma; magnitudes ~1250 m) upstream near the headwaters. We interpret this upstream increase in river incision rate and magnitude to reflect Neogene uplift of the Yampa River headwaters relative to its lower reaches. Lastly, differential late Cenozoic uplift of the Colorado Rockies is suggested by differences in the timing of regional exhumation and river incision within different drainage basins. Colorado River incision and regional exhumation occurred between 9.8 and 7.8 Ma. In contrast, Yampa River incision began between

  1. HYDROLOGY OF CENTRAL GREAT BASIN MEADOW ECOSYSTEMS – EFFECTS OF STREAM INCISION

    EPA Science Inventory

    Riparian wet meadow complexes in the mountains of the central Great Basin are scarce, ecologically important systems that are threatened by stream incision. Our interdisciplinary group has investigated 1) the interrelationships of geomorphology, hydrology, and vegetation; and 2) ...

  2. Secondary rhinoplasty using flying-bird and vestibular tornado incisions for unilateral cleft lip patients.

    PubMed

    Matsuya, Tokuzo; Iida, Seiji; Kogo, Mikihiko

    2003-08-01

    To correct the nasal deformity in cleft lip patients, a new procedure of open rhinoplasty using a "flying-bird" incision in the nostril tip with a vestibule "tornado"-shaped incision in the cleft side is presented. The newly designed vestibular incision produces effective vestibular advancement with the freed lower lateral cartilage. The flying-bird incision makes it possible to produce a suitable nostril tip appearance with symmetrical external nostril vestibules. If the vestibular defect after flap advancement is wide, a full-thickness skin graft is used to give priority for making a good external nostril shape. This procedure is useful for most cleft lip noses, particularly in cases of moderate to severe deformity. PMID:12900595

  3. Stratigraphy of the Mississippi-Alabama shelf and the Mobile River incised-valley system

    USGS Publications Warehouse

    Kindinger, Jack G.; Balson, Peter S.; Flocks, James G.

    1994-01-01

    The Holocene incised-valley fill (estuarine facies) underlying Mobile Buy fit well into the conceptual facies model of a microtidal wave-dominated estuary. The model does not fit as well, however, with the rapidly transgressed shelf portion of the incised valley. The down dip section does not contain a clearly identifiable (from seismic profiles) estuarine facies; the valley fill is primarily fluvial and is overlain by marine shoals. In the Mobile River incised valley, the distal portion of the valley was rapidly drowned, allowing the thin estuarine facies to be reworked. The proximal portion was drowned more slowly, leaving the estuarine facies intact. Thus, the single incised valley contains two very different types of fill.

  4. A "bicycle-handlebar" type of incision for primary and secondary abdominoplasty.

    PubMed

    Baroudi, R; Moraes, M

    1995-01-01

    The authors register a revision of the literature regarding the types of low transversal pubic incisions used in abdominoplasty. Since 1987, the traditional open W-type incision changed to a new type called the bicycle handlebar. In this procedure, the pubic segment remains in a lower line at the level of the pubic hair, while the lateral limbs are in a high position. The anterior superior iliac spine is used as reference. Different types of procedures where the umbilical skin hole reaches the pubic incision are described and illustrated. This procedure is also used in secondary abdominoplasty. In all cases, the incision's new position should remain hidden under a bathing suit. PMID:7484469

  5. Single-incision laparoscopic-assisted ileal resection for adult intussusception

    PubMed Central

    Yu, Hong; Wu, Shuodong; Zhu, Renzhong; Yu, Xiaopeng

    2016-01-01

    Adult intussusception is rare and laparotomy is required in most of the cases due to the potential pathologic underlying reasons. Although it is technically challenging, single-incision laparoscopic surgery can work as an alternative to laparotomy. Here we report the case of a 45-year-old man with intermittent right lower quadrant abdominal pain for 1 month. Abdominal enhanced computed tomography (CT) scan was performed and ileo-ileal intussusception was found, with lipoma as a likely leading point. Ileal resection was performed using the single-incision laparoscopic-assisted technique. Multiple trocars in the umbilical incision technique and conventional instruments were used. After identification of the ileo-ileal intussusception, the involved small bowel was extracted from the umbilical incision, and resection and anastomosis were performed extracoporeally. The operation time was 65 min and the post-operative hospital stay was 2 days. The patient recovered uneventfully, with better cosmetic results. PMID:27073316

  6. Effects of incision and irradiation on regional lymph node metastasis in carcinoma of the hamster tongue

    SciTech Connect

    Ohtake, K.; Shingaki, S.; Nakajima, T. )

    1990-07-01

    The effects of incision and irradiation on regional lymph node metastasis in DMBA-induced squamous cell carcinomas of the hamster tongue are reported. Metastasis to the submandibular lymph nodes was confirmed histologically in 48.0% of the animals. The incidence of lymph node metastasis was significantly increased (65.9%) after repeated incisions of tongue carcinomas. Three gray whole-body irradiation also increased the rate of metastasis from 31.0% to 46.3%. Higher incidences of lymphatic vessel invasion after incision and concomitant lymph node metastasis in the lymphatic invasion-positive group indicated a stepwise relationship leading to an increase in lymph node metastasis after incision. Because of the high incidence of metastases and close resemblance to human carcinomas in the tumor cell deposition and establishment of metastatic foci, DMBA-induced tongue carcinoma with invasion may serve as an experimental model of human oral carcinomas.

  7. Modeling post-wildfire fluvial incision and terrace formation

    NASA Astrophysics Data System (ADS)

    Rengers, F. K.; Tucker, G. E.

    2013-12-01

    Wildfires often lead to rapid erosion, sedimentation, and morphologic change. One of the challenges in developing quantitative models of post-fire landscape dynamics is a lack of high-quality datasets that document fluvial system evolution in the years to decades following a destructive fire. This study takes advantage of a natural experiment in post-fire fluvial incision to explore how the magnitude and timing of large flow events following a wildfire can change fluvial channel patterns. The study site is the Spring Creek watershed located in the foothills of central Colorado approximately 26 miles southwest of Denver, Colorado. The site burned during the Buffalo Creek wildfire, which was contained in May 1996. Within the Spring Creek watershed, 79% of the basin was burned and 63% of the burned area was considered high severity (Moody and Martin, 2001). In July 1996 a large rain storm hit the burned watershed and 110 mm of rain fell in one hour (Jarrett, 2001). This storm was larger than the estimated 100-year rainfall intensity of 60 mm/hr. Due to the increased surface erodibility after the wildfire, rapid erosion occurred within the watershed, while the main valley of Spring Creek aggraded with up to 2 m of sediment after this storm. Spring Creek has been incising through this post-wildfire sediment since the 1996 storm, and the terraces from this initial storm are still prevalent and identifiable along the valley. Repeated measurements of valley cross-sections since 1996 provide a comprehensive dataset for testing models of fluvial-system evolution on a decadal time scale. We hypothesize that the current channel pattern results from the specific sequence of rain events that occurred within the four years after the initial 1996 storm filled the valley with sediment. This hypothesis was tested using a two-dimensional coupled model of shallow-water flow, sediment transport, and topographic evolution. Discharge data were obtained from a stream gage installed at

  8. Phacoemulsification versus small incision cataract surgery in patients with uveitis

    PubMed Central

    Bhargava, Rahul; Kumar, Prachi; Sharma, Shiv Kumar; Kumar, Manoj; Kaur, Avinash

    2015-01-01

    AIM To compare the safety and efficacy of phacoemulsification and small incision cataract surgery (SICS) in patients with uveitic cataract. METHODS In a prospective, randomized multi-centric study, consecutive patients with uveitic cataract were randomized to receive phacoemulsification or manual SICS by either of two surgeons well versed with both the techniques. A minimum inflammation free period of 3mo (defined as less than 5 cells per high power field in anterior chamber) was a pre-requisite for eligibility for surgery. Superior scleral tunnel incisions were used for both techniques. Improvement in visual acuity post-operatively was the primary outcome measure and the rate of post-operative complications and surgical time were secondary outcome measures, respectively. Means of groups were compared using t-tests. One way analysis of variance (ANOVA) was used when there were more than two groups. Chi-square tests were used for proportions. Kaplan Meyer survival analysis was done and means for survival time was estimated at 95% confidence interval (CI). A P value of <0.05 was considered statistically significant. RESULTS One hundred and twenty-six of 139 patients (90.6%) completed the 6-month follow-up. Seven patients were lost in follow up and another six excluded due to either follow-up less than six months (n=1) or inability implant an intraocular lens (IOL) because of insufficient capsular support following posterior capsule rupture (n=5). There was significant improvement in vision after both the procedures (paired t-test; P<0.001). On first postoperative day, uncorrected distance visual acuity (UDVA) was 20/63 or better in 31 (47%) patients in Phaco group and 26 (43.3%) patients in SICS group (P=0.384). The mean surgically induced astigmatism (SIA) was 0.86±0.34 dioptres (D) in the phacoemulsification group and 1.16±0.28 D in SICS group. The difference between the groups was significant (t-test, P=0.002). At 6mo, corrected distance visual acuity (CDVA) was

  9. The Deckled Incision: Study Protocol for a Randomized Controlled Trial

    PubMed Central

    Lord, Sarah J; Ngo, Quan

    2016-01-01

    Background Scar visibility is multifactorial and skin closure technique is thought to play an important role. It is an established principle in plastic surgery that Z plasties generally reduce scar contracture by breaking up the lines of tension in a wound. As an extension of this principle, it is postulated that irregular “deckled” skin incisions made during tumor excision would produce aesthetically superior scars. Objective The primary objective of this study is to assess both the clinician and patient opinion of scar quality using the Patient and Observer Scar Assessment Scale (POSAS). Secondary objectives include the proportion of scars judged as good by the both the patient and clinician (less than or equal to 5 on the overall PSOAS scale), the number of adverse events, and the proportion of the scar visible at 1 meter. Methods The deckling study will be a patient-blinded, simple randomized controlled trial (RCT) at a single center institution. The two groups will be equally allocated on a 1:1 ratio into the control and treatment arms. All patients greater than 18 years of age undergoing a plastic surgery procedure involving excision of skin lesions will be enrolled. Any patients requiring re-excision through the wound or undergoing injectable corticosteroid therapy will be excluded. A total of 500 patients will be enrolled. The patients will be followed-up at 1 week, 3 months, and 6 months post-operatively. Results The study is expected to begin enrolment in August 2016. We anticipate that the deckling study group will have superior scar outcomes when compared to the straight line incision. From clinical experience this is especially true for lesions involving the face and in those areas of the skin that have undergone radiation therapy. The study will be funded by the Plastics and Reconstructive Surgery Department at St Vincent’s Hospital, Sydney, Australia. Ethics approval has been obtained for the study. Conclusion: We believe this will be an

  10. Open mini-incision parathyroidectomy for solitary parathyroid adenoma.

    PubMed

    Kelly, Ciaran W P; Eng, Chee-Yean; Quraishi, M Shahed

    2014-03-01

    Parathyroid surgery is the acceptable definitive treatment for primary hyperparathyroidism (pHPT) due to parathyroid adenoma. Open mini-incision parathyroidectomy (O-MIP) has an excellent cure rate and minimal morbidity. We aim to demonstrate the safety, efficacy and subjective patient satisfaction of O-MIP and investigate the accuracy of pre-operative radiological localisation in relation to operative findings. A retrospective review of patients who underwent O-MIP for pHPT due to solitary parathyroid adenoma from April 2006 to August 2012 was performed. All patients were initially investigated by an endocrinologist to confirm pHPT with pre-operative localisation imaging using ultrasound scan (USS) and 99mTc-sestamibi (MIBI). One hundred and fifty consecutive patients were included with a median age of 62 years. Pre-operative USS and MIBI scans were concordant in 71 % of cases. In combined modality (USS and MIBI), localisation was 94.8 % accurate. There was 95.5 % identification of parathyroid tissue confirmed by intra-operative frozen section. Ninety-one percent of patients were treated as a day case. The median operative time was 60 min. The mean pre-operative calcium level was 2.98 mmol/l, and the short-to-medium term mean calcium level was 2.49 (Paired t test, p < 0.001). There was no significant complication. O-MIP confers significant advantages over the traditional gold standard treatment of bilateral neck exploration. Accurate localisation is the key to successful O-MIP. In experienced hands, ultrasound and MIBI may be the only pre-operative investigations required for accurate localisation. PMID:23653305

  11. Central corneal thickness changes following manual small incision cataract surgery

    PubMed Central

    Aribaba, Olufisayo Temitayo; Adenekan, Olusesan Adetunji; Onakoya, Adeola Olukorede; Rotimi-Samuel, Adekunle; Olatosi, John Olutola; Musa, Kareem Olatunbosun; Oyefeso, Akinyele Oyedele; Akinsola, Folashade Bolanle

    2015-01-01

    Aim To determine changes in post-cataract surgery central corneal thickness (CCT) at Lagos University Teaching Hospital by assessing the time it takes for the cornea to return to its preoperative thickness value. Methods This study is a prospective, hospital-based open within-patient controlled study with the unoperated eye controlling for the operated one. Results Two hundred patients with 400 eyes were analyzed, with bilateral mature cataract in 47.0%. All the patients had manual small incision cataract surgery with posterior chamber intraocular lens implant. There is an increase in mean baseline CCT from 520.6±20.3 μm by 76.9 μm (597.9±30.4 μm) 24 hours after cataract surgery followed by relative reduction in the mean CCT to 555.2±24.7 μm and 525.1±19.7 μm at 2 weeks and 12 weeks, respectively. Increase in mean CCT in the unoperated and contralateral eyes were recorded in this study. Conclusion There was a transient increase in corneal thickness following cataract surgery with subsequent decrease to preoperative thickness by 12th and fourth week in the operated and unoperated eyes, respectively. Corneal manipulations during cataract surgery must be minimal to reduce visual rehabilitation time to barest minimum. Postoperative refraction will be better at eighth week to 12th week considering the time it takes for the CCT to return to its stable preoperative values. PMID:25653497

  12. Feasibility of single-incision laparoscopic cholecystectomy for acute cholecystitis

    PubMed Central

    Ikumoto, Taro; Yamagishi, Hidetsugu; Iwatate, Mineo; Sano, Yasushi; Kotaka, Masahito; Imai, Yasuo

    2015-01-01

    AIM: To assess the safety of single-incision laparoscopic cholecystectomy (SILC) for acute cholecystitis. METHODS: All patients who underwent SILC at Sano Hospital (Kobe, Japan) between January 2010 and December 2014 were included in this retrospective study. Clinical data related to patient characteristics and surgical outcomes were collected from medical records. The parameters for assessing the safety of the procedure included operative time, volume of blood loss, achievement of the critical view of safety, use of additional trocars, conversion to laparotomy, intraoperative and postoperative complications, and duration of postoperative hospital stay. Patient backgrounds were statistically compared between those with and without conversion to laparotomy. RESULTS: A total of 100 patients underwent SILC for acute cholecystitis during the period. Preoperative endoscopic treatment was performed for suspected choledocholithiasis in 41 patients (41%). The mean time from onset of acute cholecystitis was 7.7 d. According to the Updated Tokyo Guidelines (TG13) for the severity of cholecystitis, 86 and 14 patients had grade I and grade II acute cholecystitis, respectively. The mean operative time was 87.4 min. The mean estimated blood loss was 80.6 mL. The critical view of safety was obtained in 89 patients (89%). Conversion laparotomy was performed in 12 patients (12%). Postoperative complications of Clavien-Dindo grade III or greater were observed in 4 patients (4%). The mean duration of postoperative hospital stay was 5.7 d. Patients converted from SILC to laparotomy tended to have higher days after onset. CONCLUSION: SILC is feasible for acute cholecystitis; in addition, early surgical intervention may reduce the risk of laparotomy conversion. PMID:26722614

  13. Accuracy and stability of positioning in radiosurgery: long-term results of the Gamma Knife system.

    PubMed

    Heck, Bernhard; Jess-Hempen, Anja; Kreiner, Hans Jürg; Schöpgens, Hans; Mack, Andreas

    2007-04-01

    The primary aim of this investigation was to determine the long term overall accuracy of an irradiation position of Gamma Knife systems. The mechanical accuracy of the system as well as the overall accuracy of an irradiation position was examined by irradiating radiosensitive films. To measure the mechanical accuracy, the GafChromic film was fixed by a special tool at the unit center point (UCP). For overall accuracy the film was mounted inside a phantom at a target position given by a two-dimensional cross. Its position was determined by CT or MRI scans, a treatment was planned to hit this target by use of the standard planning software and the radiation was finally delivered. This procedure is named "system test" according to DIN 6875-1 and is equivalent to a treatment simulation. The used GafChromic films were evaluated by high resolution densitometric measurements. The Munich Gamma Knife UCP coincided within x; y; z: -0.014 +/- 0.09 mm; 0.013 +/- 0.09 mm; -0.002 +/- 0.06 mm (mean +/- SD) to the center of dose distribution. There was no trend in the measured data observed over more than ten years. All measured data were within a sphere of 0.2 mm radius. When basing the target definition in the system test on MRI scans, we obtained an overall accuracy of an irradiation position in the x direction of 0.21 +/- 0.32 mm and in the y direction 0.15 +/- 0.26 mm (mean +/- SD). When a CT-based target definition was used, we measured distances in x direction 0.06 +/- 0.09 mm and in y direction 0.04 +/- 0.09 mm (mean +/- SD), respectively. These results were compared with those obtained with a Gamma Knife equipped with an automatic positioning system (APS) by use of a different phantom. This phantom was found to be slightly less accurate due to its mechanical construction and the soft fixation into the frame. The phantom related position deviation was found to be about +/- 0.2 mm, and therefore the measured accuracy of the APS Gamma Knife was evidently less precise by

  14. Channel Incision and Suspended Sediment Delivery at Caspar Creek, Mendocino County, California.

    NASA Astrophysics Data System (ADS)

    Dewey, N. J.; Lisle, T. E.; Reid, L. M.

    2003-12-01

    Tributary and headwater valleys in the Caspar Creek watershed, in coastal Mendocino County, California, show signs of incision along much of their lengths. An episode of incision followed initial-entry logging which took place between 1860 and 1906. Another episode of incision cut into skid-trails created for second-entry logging in the 1970's. Gullies resulting from both of these episodes of incision are sensitive to hydrologic fluctuations and feature active headcuts, deepening plungepools, and unstable banks, which continue to contribute sediment to the Caspar Creek channel network. Headcuts are numerous in each channel. In some cases headcuts define the upstream extent of an incised reach; in many cases headcuts migrate up previously incised reaches, increasing the depth of incision. Surveys indicate that bank retreat, plunge pool deepening, and headcut retreat all contributed sediment to the channels between 2000 and 2003. Since bank walls have considerably more surface area than headwalls per given length of channel, and headcuts have largely migrated into positions temporarily constrained by resistant lips, bankwall retreat appears to be a more significant chronic source of sediment than headwall retreat. Stream gage records show that some channels consistently deliver higher levels of suspended sediment than others. In comparing channels, ongoing levels of suspended sediment delivery correlate well with total amount of exposed channel bank (depth of incision integrated over length of channel) in the reaches upstream of stream gages. On an annual to decadal time-scale, rates of suspended sediment delivery per unit area of catchment correlate better with the amount of exposed bank area in reaches upstream of stream gages, than with the volume of sediment delivered by landslide events, with total catchment area, or with peak storm flow per unit area. The correlation between amount of exposed bank area and ongoing levels of suspended sediment delivery is

  15. The prevalence of mandibular incisive nerve canal and to evaluate its average location and dimension in Indian population

    PubMed Central

    Ramesh, A. S.; Rijesh, K.; Sharma, Aruna; Prakash, R.; Kumar, Arun; Karthik

    2015-01-01

    Aim: The aim of this study was to find the prevalence of the mandibular incisive canal, evaluate its location and dimensions using cone beam computer tomography (CBCT) in Indian population. Materials and Methods: CBCT scan images of 120 subjects were analyzed for the presence of the mandibular incisive canal, its location, size, and its length. The distance between the incisive canal and the buccal and lingual plate of the alveolar bone, and the distance from the canal to the inferior border of the mandible were also measured to position the canal in the mandible. Results: About 71.66% of the CBCT scans of Indian subjects examined showed the presence of the Incisive canal, of which 48.33% exhibited canals bilaterally and 23.33% showed unilateral canals. 28.33% of the subjects CBCT scans did not exhibit the presence of incisive nerve canal. The average length of the incisive canal was 10.173 mm. The average diameter of the Incisive canal in the CBCT scans was 2.578 mm. The distance from the Inferior border of the mandible to (a) the origin of the Incisive canal was 9.425 mm and (b) to the apex of the Incisive canal was 9.095 mm. The distance from the buccal cortex of the mandible to (a) the origin of the incisive canal was 1.48 mm and (b) to the apex of the incisive canal was 4.476 mm. The distance from the lingual cortex of the mandible to (a) the origin of the incisive canal was 4.464 mm and (b) to the apex of the incisive canal was 5.561 mm. Conclusion: The presence, location, and dimensions of the mandibular incisive canal are an additional required data that needs to be elicited before planning an inter-foraminal placement of implants. PMID:26538925

  16. Controls on aggradation and incision in the NE Negev, Israel, since the middle Pleistocene

    DOE PAGESBeta

    Matmon, A.; Elfasi, S.; Hidy, A. J.; Geller, Y.; Porat, N.; Team, ASTER

    2016-02-23

    Here, we investigated the mid-Pleistocene to recent aggradation-incision pattern of two drainage systems (Nahal Peres and Nahal Tahmas) in the hyperarid north eastern Negev desert, southern Israel. Although these drainage systems drain into the tectonically active Dead Sea basin, lake level fluctuations cannot account for the aggradation-incision pattern as bedrock knickpoints disconnect the investigated parts of these drainage systems from base level influence. We applied geomorphic mapping, soil stratigraphy, optically stimulated luminescence (OSL) and cosmogenic (in situ 10Be) exposure dating to reconstruct cycles of aggradation and incision of alluvial terraces and to study their temporal association with regional periods ofmore » humidity and aridity and global glacial-interglacial cycles. The spatial and temporal relationships between the alluvial units suggest changes in the drainage system behavior since the middle Pleistocene, and show a pattern in which prolonged periods of sediment aggradation alternated with short periods of rapid and intense degradation through erosion and incision into sediment and bedrock. We obtain ages for several Pleistocene-Holocene periods of incision: ~ 1.1 Ma, ~ 300 ka, ~ 120 ka, ~ 20 ka, ~ 12 ka and ~ 2 ka. Although broadly synchronous, the Nahal Peres and Nahal Tahmas systems exhibit temporal differences in aggradation and incision.« less

  17. Evaluation of four suture materials for surgical incision closure in Siberian sturgeon

    USGS Publications Warehouse

    Boone, S. Shaun; Hernandez, Sonia M.; Camus, Alvin C.; Peterson, Douglas C.; Jennings, Cecil A.; Shelton, James L.; Divers, Stephen J.

    2015-01-01

    The visual and microscopic tissue reactions to the absorbable monofilament Monocryl, absorbable monofilament triclosan-coated Monocryl-Plus, absorbable multifilament Vicryl, and nonabsorbable monofilament Prolene were evaluated for their use of surgical closure in Siberian Sturgeon Acipenser baerii. Postoperative assessments were conducted at 1, 2, 8, 12, and 26 and 55 weeks to visually evaluate the surgical incision for suture retention, incision healing, erythema, and swelling. Incisions were also assessed microscopically at 1, 2, and 8 weeks for necrosis, inflammation, hemorrhage, and fibroplasia. The results indicated that incisions closed with either Vicryl or Prolene suture materials were more likely to exhibit more erythema or incomplete healing compared with those closed with Monocryl or Monocryl-Plus. The surgical implantation of a transmitter in the coelomic cavity did not significantly affect the response variables among the four suture materials. Monocryl or Monocryl-Plus were equally effective and superior to other suture materials used for closing surgical incisions in Siberian Sturgeon or closely related species of sturgeon. Furthermore, Monocryl or Monocryl-Plus may decrease the risk of transmitter expulsion through the incision, as surgical wounds appear to heal faster and exhibit less erythema compared with those closed with Vicryl.

  18. Temperature-controlled laser-soldering system and its clinical application for bonding skin incisions.

    PubMed

    Simhon, David; Gabay, Ilan; Shpolyansky, Gregory; Vasilyev, Tamar; Nur, Israel; Meidler, Roberto; Hatoum, Ossama Abu; Katzir, Abraham; Hashmonai, Moshe; Kopelman, Doron

    2015-01-01

    Laser tissue soldering is a method of repairing incisions. It involves the application of a biological solder to the approximated edges of the incision and heating it with a laser beam. A pilot clinical study was carried out on 10 patients who underwent laparoscopic cholecystectomy. Of the four abdominal incisions in each patient, two were sutured and two were laser soldered. Cicatrization, esthetical appearance, degree of pain, and pruritus in the incisions were examined on postoperative days 1, 7, and 30. The soldered wounds were watertight and healed well, with no discharge from these wounds or infection. The total closure time was equal in both methods, but the net soldering time was much shorter than suturing. There was no difference between the two types of wound closure with respect to the pain and pruritus on a follow-up of one month. Esthetically, the soldered incisions were estimated as good as the sutured ones. The present study confirmed that temperature-controlled laser soldering of human skin incisions is clinically feasible, and the results obtained were at least equivalent to those of standard suturing. PMID:26720882

  19. Temperature-controlled laser-soldering system and its clinical application for bonding skin incisions

    NASA Astrophysics Data System (ADS)

    Simhon, David; Gabay, Ilan; Shpolyansky, Gregory; Vasilyev, Tamar; Nur, Israel; Meidler, Roberto; Hatoum, Ossama Abu; Katzir, Abraham; Hashmonai, Moshe; Kopelman, Doron

    2015-12-01

    Laser tissue soldering is a method of repairing incisions. It involves the application of a biological solder to the approximated edges of the incision and heating it with a laser beam. A pilot clinical study was carried out on 10 patients who underwent laparoscopic cholecystectomy. Of the four abdominal incisions in each patient, two were sutured and two were laser soldered. Cicatrization, esthetical appearance, degree of pain, and pruritus in the incisions were examined on postoperative days 1, 7, and 30. The soldered wounds were watertight and healed well, with no discharge from these wounds or infection. The total closure time was equal in both methods, but the net soldering time was much shorter than suturing. There was no difference between the two types of wound closure with respect to the pain and pruritus on a follow-up of one month. Esthetically, the soldered incisions were estimated as good as the sutured ones. The present study confirmed that temperature-controlled laser soldering of human skin incisions is clinically feasible, and the results obtained were at least equivalent to those of standard suturing.

  20. Watershed-scale modeling of streamflow change in incised montane meadows

    NASA Astrophysics Data System (ADS)

    Essaid, Hedeff I.; Hill, Barry R.

    2014-03-01

    Land use practices have caused stream channel incision and water table decline in many montane meadows of the Western United States. Incision changes the magnitude and timing of streamflow in water supply source watersheds, a concern to resource managers and downstream water users. The hydrology of montane meadows under natural and incised conditions was investigated using watershed simulation for a range of hydrologic conditions. The results illustrate the interdependence between: watershed and meadow hydrology; bedrock and meadow aquifers; and surface and groundwater flow through the meadow for the modeled scenarios. During the wet season, stream incision resulted in less overland flow and interflow and more meadow recharge causing a net decrease in streamflow and increase in groundwater storage relative to natural meadow conditions. During the dry season, incision resulted in less meadow evapotranspiration and more groundwater discharge to the stream causing a net increase in streamflow and a decrease in groundwater storage relative to natural meadow conditions. In general, for a given meadow setting, the magnitude of change in summer streamflow and long-term change in watershed groundwater storage due to incision will depend on the combined effect of: reduced evapotranspiration in the eroded meadow; induced groundwater recharge; replenishment of dry season groundwater storage depletion in meadow and bedrock aquifers by precipitation during wet years; and groundwater storage depletion that is not replenished by precipitation during wet years.

  1. Relaxation schemes for Chebyshev spectral multigrid methods

    NASA Technical Reports Server (NTRS)

    Kang, Yimin; Fulton, Scott R.

    1993-01-01

    Two relaxation schemes for Chebyshev spectral multigrid methods are presented for elliptic equations with Dirichlet boundary conditions. The first scheme is a pointwise-preconditioned Richardson relaxation scheme and the second is a line relaxation scheme. The line relaxation scheme provides an efficient and relatively simple approach for solving two-dimensional spectral equations. Numerical examples and comparisons with other methods are given.

  2. Phase transitions in semidefinite relaxations

    PubMed Central

    Javanmard, Adel; Montanari, Andrea; Ricci-Tersenghi, Federico

    2016-01-01

    Statistical inference problems arising within signal processing, data mining, and machine learning naturally give rise to hard combinatorial optimization problems. These problems become intractable when the dimensionality of the data is large, as is often the case for modern datasets. A popular idea is to construct convex relaxations of these combinatorial problems, which can be solved efficiently for large-scale datasets. Semidefinite programming (SDP) relaxations are among the most powerful methods in this family and are surprisingly well suited for a broad range of problems where data take the form of matrices or graphs. It has been observed several times that when the statistical noise is small enough, SDP relaxations correctly detect the underlying combinatorial structures. In this paper we develop asymptotic predictions for several detection thresholds, as well as for the estimation error above these thresholds. We study some classical SDP relaxations for statistical problems motivated by graph synchronization and community detection in networks. We map these optimization problems to statistical mechanics models with vector spins and use nonrigorous techniques from statistical mechanics to characterize the corresponding phase transitions. Our results clarify the effectiveness of SDP relaxations in solving high-dimensional statistical problems. PMID:27001856

  3. Phase transitions in semidefinite relaxations.

    PubMed

    Javanmard, Adel; Montanari, Andrea; Ricci-Tersenghi, Federico

    2016-04-19

    Statistical inference problems arising within signal processing, data mining, and machine learning naturally give rise to hard combinatorial optimization problems. These problems become intractable when the dimensionality of the data is large, as is often the case for modern datasets. A popular idea is to construct convex relaxations of these combinatorial problems, which can be solved efficiently for large-scale datasets. Semidefinite programming (SDP) relaxations are among the most powerful methods in this family and are surprisingly well suited for a broad range of problems where data take the form of matrices or graphs. It has been observed several times that when the statistical noise is small enough, SDP relaxations correctly detect the underlying combinatorial structures. In this paper we develop asymptotic predictions for several detection thresholds, as well as for the estimation error above these thresholds. We study some classical SDP relaxations for statistical problems motivated by graph synchronization and community detection in networks. We map these optimization problems to statistical mechanics models with vector spins and use nonrigorous techniques from statistical mechanics to characterize the corresponding phase transitions. Our results clarify the effectiveness of SDP relaxations in solving high-dimensional statistical problems. PMID:27001856

  4. Characterization of non-Gaussian mid-infrared free-electron laser beams by the knife-edge method

    NASA Astrophysics Data System (ADS)

    Qin, Yu; Nakajima, Takashi; Zen, Heishun; Wang, Xiaolong; Kii, Toshiteru; Ohgaki, Hideaki

    2014-09-01

    We report the characterization of mid-infrared free-electron laser (FEL) beams at the wavelength of 11 μm by the knife-edge method. From the knife-edge data we find that the FEL beam has a non-Gaussian shape. To represent the non-Gaussian beam shape we employ two methods: fitting the knife-edge data to some analytical functions with a few free parameters and numerical smoothing of the knife-edge data. Both methods work equally well. Using those data we can reconstruct the two-dimensional (2D) beam profiles at different positions around the focus by assuming that the 2D intensity distribution function is separable in x (horizontal) and y (vertical) directions. Using the 2D beam profiles at different positions around the focus, we find that the beam propagation factor (M2 factor) is ∼1.1 in both x and y directions. As a cross-check, we also carry out the burn pattern experiment to find that the behavior of the focused FEL beam along the propagation is consistent with the results obtained by the knife-edge method.

  5. A simple and effective method for validation and measurement of collimator output factors for Leksell Gamma Knife® Perfexion™

    NASA Astrophysics Data System (ADS)

    Ma, Lijun; Kjäll, Per; Novotny, Josef Jr; Nordström, Håkan; Johansson, Jonas; Verhey, Lynn

    2009-06-01

    Accurate determination of collimator output factors is important for Leksell Gamma Knife radiosurgery. The new Leksell Gamma Knife® Perfexion™ system has a completely redesigned collimator system and the collimator output factors are different from the other Leksell Gamma Knife® models. In this study, a simple method was developed to validate the collimator output factors specifically for Leksell Gamma Knife® Perfexion™. The method uses double-shot exposures on a single film to eliminate repeated setups and the necessity to acquire dose calibration curves required for the traditional film exposure method. Using the method, the collimator output factors with respect to the 16 mm collimator were measured to be 0.929 ± 0.009 and 0.817 ± 0.012 for the 8 mm and the 4 mm collimator, respectively. These values are in agreement (within 2%) with the default values of 0.924 and 0.805 in the Leksell Gamma Plan® treatment planning system. These values also agree with recently published results of 0.917 (8 mm collimator) and 0.818 (4 mm collimator) obtained from the traditional methods. Given the efficiency of the method, measurement and validation of the collimator output factors can be readily adopted in commissioning and quality assurance of a Leksell Gamma Knife® Perfexion™ system.

  6. A Precise 6 Ma Start Date for Fluvial Incision of the Northeastern Colorado Plateau Canyonlands

    NASA Astrophysics Data System (ADS)

    Thomson, S. N.; Soreghan, G. S.; Reiners, P. W.; Peyton, S. L.; Murray, K. E.

    2015-12-01

    Outstanding questions regarding late Cenozoic Colorado Plateau landscape evolution include: (1) the relative roles of isostatic rebound as result Colorado River incision versus longer-term geodynamic processes in driving overall rock uplift of the plateau; and (2) whether incision was triggered by river integration or by a change in deep-seated mantle lithosphere dynamics. A key to answering these questions is to date more precisely the onset of incision to refine previous estimates of between 6 and 10 Ma. We present new low-temperature thermochronologic results from bedrock and deep borehole samples in the northeastern Colorado Plateau to show that rapid river incision began here at 6 Ma (5.93±0.66 Ma) with incision rates increasing from 15-50 m/Myr to 160-200 m/Myr. The onset time is constrained independently by both inverse time-temperature modeling and by the break-in-slope in fission track age-elevation relationships. This new time constraint has several important implications. First, the coincidence in time with 5.97-5.3 Ma integration of the lower Colorado River through the Grand Canyon to the Gulf of California strongly favors downstream river integration triggering carving of the canyonlands of the upper Colorado River system. Second, it implies integration of the entire Colorado River system in less than 2 million years. Third, rock uplift of the plateau driven by the flexural isostatic response to river incision is restricted to just the last 6 Ma, as is associated increased sediment budget. Fourth, incision starting at 6 Ma means that previous estimates of upper Colorado River incision rates based on 10-12 Ma basalt datum levels are too low. This also changes the dependency of measured time interval on incision rate from a non-steady-state negative power-law dependence (exponent of -0.24) to a near steady-state dependence (exponent of 0.07) meaning that long-term upper Colorado river incision rates can provide a reliable proxy for rock uplift rates.

  7. Posterior corneal curvature changes following Refractive Small Incision Lenticule Extraction

    PubMed Central

    Ganesh, Sri; Patel, Utsav; Brar, Sheetal

    2015-01-01

    Purpose To compare the posterior corneal curvature changes, in terms of corneal power and asphercity, following Refractive Small Incision Lenticule Extraction (ReLEx SMILE) procedure for low, moderate, and high myopia. Methods This retrospective, non randomized, comparative, interventional trial; included 52 eyes of 26 patients, divided in three groups: low myopia (myopia ≤3 D [diopters] spherical equivalent [SE]), moderate myopia (myopia >3 D and <6 D SE), and high myopia (myopia ≥6 D SE). All patients were treated for myopia and myopic astigmatism using ReLEx SMILE. The eyes were examined pre-operatively and 3 months post-operatively using SCHWIND SIRIUS, a three-dimensional rotating Scheimpflug camera with a Placido disc topographer to assess corneal changes with regard to keratometric power and asphericity of the cornea. Results A statistically significant increase in mean keratometric power in the 3, 5, and 7 mm zones of the posterior corneal surface compared with its pre-ReLEx SMILE value was detected after 3 months in the moderate myopia group (pre-operative [pre-op] −6.14±0.23, post-operative [post-op] −6.29±0.22, P<0.001) and high myopia group (pre-op −6.19±0.16, post-op −6.4±0.18, P<0.001), but there was no significant change in keratometric power of the posterior surface in the low myopia group (pre-op −5.87±0.17, post-op −6.06±0.29, P=0.143). Asphericity (Q-value) of the posterior surface changed significantly (P<0.001) after ReLEx SMILE in the moderate myopia group in the 3, 5, and 7 mm zones, and in the high myopia group in the 3 and 7 mm zones; but there was no significant change in the Q-value in the low myopia group in all three zones (pre-op 0.23±0.43, post-op −0.40±0.71, P=0.170), and in the high myopia group in the 5 mm zone (P=0.228). Conclusion ReLEx SMILE causes significant changes in posterior corneal keratometric power and asphericity in moderate and high myopia, but the effect is subtle and insignificant in low

  8. Global relaxation of superconducting qubits

    SciTech Connect

    Ojanen, T.; Niskanen, A. O.; Nakamura, Y.; Abdumalikov, A. A. Jr.

    2007-09-01

    We consider coupled quantum two-state systems (qubits) exposed to a global relaxation process. The global relaxation refers to the assumption that qubits are coupled to the same quantum bath with approximately equal strengths, appropriate for long-wavelength environmental fluctuations. We show that interactions do not spoil the picture of Dicke's subradiant and super-radiant states where quantum interference effects lead to striking deviations from the independent relaxation picture. Remarkably, the system possess a stable entangled state and a state decaying faster than single qubit excitations. We propose a scheme for how these effects can be experimentally accessed in superconducting flux qubits and, possibly, used in constructing long-lived entangled states.

  9. Shoreline relaxation at pocket beaches

    NASA Astrophysics Data System (ADS)

    Turki, Imen; Medina, Raul; Kakeh, Nabil; González, Mauricio

    2015-09-01

    A new physical concept of relaxation time is introduced in this research as the time required for the beach to dissipate its initial perturbation. This concept is investigated using a simple beach-evolution model of shoreline rotation at pocket beaches, based on the assumption that the instantaneous change of the shoreline plan-view shape depends on the long-term equilibrium plan-view shape. The expression of relaxation time is developed function of the energy conditions and the physical characteristics of the beach; it increases at longer beaches having coarse sediments and experiencing low-energy conditions. The relaxation time, calculated by the developed model, is validated by the shoreline observations extracted from video images at two artificially embayed beaches of Barcelona (NW Mediterranean) suffering from perturbations of sand movement and a nourishment project. This finding is promising to estimate the shoreline response and useful to improve our understanding of the dynamic of pocket beaches and their stability.

  10. Multigrid Methods for Mesh Relaxation

    SciTech Connect

    O'Brien, M J

    2006-06-12

    When generating a mesh for the initial conditions for a computer simulation, you want the mesh to be as smooth as possible. A common practice is to use equipotential mesh relaxation to smooth out a distorted computational mesh. Typically a Laplace-like equation is set up for the mesh coordinates and then one or more Jacobi iterations are performed to relax the mesh. As the zone count gets really large, the Jacobi iteration becomes less and less effective and we are stuck with our original unrelaxed mesh. This type of iteration can only damp high frequency errors and the smooth errors remain. When the zone count is large, almost everything looks smooth so relaxation cannot solve the problem. In this paper we examine a multigrid technique which effectively smooths out the mesh, independent of the number of zones.

  11. Ellipsoidal Relaxation of Deformed Vesicles

    NASA Astrophysics Data System (ADS)

    Yu, Miao; Lira, Rafael B.; Riske, Karin A.; Dimova, Rumiana; Lin, Hao

    2015-09-01

    Theoretical analysis and experimental quantification on the ellipsoidal relaxation of vesicles are presented. The current work reveals the simplicity and universal aspects of this process. The Helfrich formula is shown to apply to the dynamic relaxation of moderate-to-high tension membranes, and a closed-form solution is derived which predicts the vesicle aspect ratio as a function of time. Scattered data are unified by a time scale, which leads to a similarity behavior, governed by a distinctive solution for each vesicle type. Two separate regimes in the relaxation are identified, namely, the "entropic" and the "constant-tension" regimes. The bending rigidity and the initial membrane tension can be simultaneously extracted from the data analysis, posing the current approach as an effective means for the mechanical analysis of biomembranes.

  12. Relaxed Poisson cure rate models.

    PubMed

    Rodrigues, Josemar; Cordeiro, Gauss M; Cancho, Vicente G; Balakrishnan, N

    2016-03-01

    The purpose of this article is to make the standard promotion cure rate model (Yakovlev and Tsodikov, ) more flexible by assuming that the number of lesions or altered cells after a treatment follows a fractional Poisson distribution (Laskin, ). It is proved that the well-known Mittag-Leffler relaxation function (Berberan-Santos, ) is a simple way to obtain a new cure rate model that is a compromise between the promotion and geometric cure rate models allowing for superdispersion. So, the relaxed cure rate model developed here can be considered as a natural and less restrictive extension of the popular Poisson cure rate model at the cost of an additional parameter, but a competitor to negative-binomial cure rate models (Rodrigues et al., ). Some mathematical properties of a proper relaxed Poisson density are explored. A simulation study and an illustration of the proposed cure rate model from the Bayesian point of view are finally presented. PMID:26686485

  13. Structural Analysis of Different Incision Sizes and Stromal Hydration in Cataract Surgery Using Anterior Segment Optical Coherence Tomography

    PubMed Central

    Bang, Jong-Wook; Lee, Jong-Hyun; Kim, Jin-Hyoung

    2015-01-01

    Purpose To analyze healing changes of corneal wounds of different corneal incision sizes with or without stromal hydration in cataract surgery using anterior segment optical coherence tomography. Methods Cataract surgeries were performed by a single surgeon and 2.2- and 2.8-mm corneal incisions were made using a diamond blade (ME-759; Meyco, Biel-Bienne, Swiss). Patients were divided into four groups according to incision size (2.2 and 2.8 mm), and with/without stromal hydration. Fifteen eyes were assigned to each group and incision wounds were measured using anterior segment optical coherence tomography at 2 hours, 1 day, 1 week, 1 month, and 3 months postoperatively. Corneal thickness, incision length and incision angle were measured and existence of epithelial, endothelial gaping and Descemet's membrane detachment was evaluated. Results Incision thickness was greater in the group with stromal hydration than in the group without on operation day (p < 0.05). Stromal hydration exerted greater influence in the 2.2-mm incision group than in the 2.8-mm incision group. Corneal thickness decreased more rapidly in the stromal hydration group than in the group with no hydration (p = 0.022). Endothelial gaping was greater in the 2.2-mm incision group than in the 2.8-mm incision group 1 day, 1 month, and 3 months after surgery (p = 0.035, p = 0.009, and p = 0.008, respectively). No other statistical significance was observed between the two groups (2.2 and 2.8 mm) during follow-up regarding corneal thickness, epithelial gaping and Descemet's membrane detachment. Conclusions Corneal wounds with a smaller incision could be more vulnerable to external stimuli such as stromal hydration and are less stable than those with a larger incision. PMID:25646057

  14. A mixed relaxed clock model

    PubMed Central

    2016-01-01

    Over recent years, several alternative relaxed clock models have been proposed in the context of Bayesian dating. These models fall in two distinct categories: uncorrelated and autocorrelated across branches. The choice between these two classes of relaxed clocks is still an open question. More fundamentally, the true process of rate variation may have both long-term trends and short-term fluctuations, suggesting that more sophisticated clock models unfolding over multiple time scales should ultimately be developed. Here, a mixed relaxed clock model is introduced, which can be mechanistically interpreted as a rate variation process undergoing short-term fluctuations on the top of Brownian long-term trends. Statistically, this mixed clock represents an alternative solution to the problem of choosing between autocorrelated and uncorrelated relaxed clocks, by proposing instead to combine their respective merits. Fitting this model on a dataset of 105 placental mammals, using both node-dating and tip-dating approaches, suggests that the two pure clocks, Brownian and white noise, are rejected in favour of a mixed model with approximately equal contributions for its uncorrelated and autocorrelated components. The tip-dating analysis is particularly sensitive to the choice of the relaxed clock model. In this context, the classical pure Brownian relaxed clock appears to be overly rigid, leading to biases in divergence time estimation. By contrast, the use of a mixed clock leads to more recent and more reasonable estimates for the crown ages of placental orders and superorders. Altogether, the mixed clock introduced here represents a first step towards empirically more adequate models of the patterns of rate variation across phylogenetic trees. This article is part of the themed issue ‘Dating species divergences using rocks and clocks’. PMID:27325829

  15. A mixed relaxed clock model.

    PubMed

    Lartillot, Nicolas; Phillips, Matthew J; Ronquist, Fredrik

    2016-07-19

    Over recent years, several alternative relaxed clock models have been proposed in the context of Bayesian dating. These models fall in two distinct categories: uncorrelated and autocorrelated across branches. The choice between these two classes of relaxed clocks is still an open question. More fundamentally, the true process of rate variation may have both long-term trends and short-term fluctuations, suggesting that more sophisticated clock models unfolding over multiple time scales should ultimately be developed. Here, a mixed relaxed clock model is introduced, which can be mechanistically interpreted as a rate variation process undergoing short-term fluctuations on the top of Brownian long-term trends. Statistically, this mixed clock represents an alternative solution to the problem of choosing between autocorrelated and uncorrelated relaxed clocks, by proposing instead to combine their respective merits. Fitting this model on a dataset of 105 placental mammals, using both node-dating and tip-dating approaches, suggests that the two pure clocks, Brownian and white noise, are rejected in favour of a mixed model with approximately equal contributions for its uncorrelated and autocorrelated components. The tip-dating analysis is particularly sensitive to the choice of the relaxed clock model. In this context, the classical pure Brownian relaxed clock appears to be overly rigid, leading to biases in divergence time estimation. By contrast, the use of a mixed clock leads to more recent and more reasonable estimates for the crown ages of placental orders and superorders. Altogether, the mixed clock introduced here represents a first step towards empirically more adequate models of the patterns of rate variation across phylogenetic trees.This article is part of the themed issue 'Dating species divergences using rocks and clocks'. PMID:27325829

  16. Statistical mechanics of violent relaxation

    NASA Technical Reports Server (NTRS)

    Spergel, David N.; Hernquist, Lars

    1992-01-01

    We propose a functional that is extremized through violent relaxation. It is based on the Ansatz that the wave-particle scattering during violent dynamical processes can be approximated as a sequence of discrete scattering events that occur near a particle's perigalacticon. This functional has an extremum whose structure closely resembles that of spheroidal stellar systems such as elliptical galaxies. The results described here, therefore, provide a simple framework for understanding the physical nature of violent relaxation and support the view that galaxies are structured in accord with fundamental statistical principles.

  17. Relaxation dynamics of branched polymers

    NASA Astrophysics Data System (ADS)

    Ghosh, Arnav

    The Rouse model for star polymers was successfully derived by solving the differential equations governing the net force acting on each bead in a star polymer chain. As opposed to a linear polymer, where we have N unique roots for N beads, in the case of star polymers, there are only 2 Na+1 unique roots and all odd unique roots (except the last root corresponding to the branch point) starting with the first root have a multiplicity of f-1. The relaxation time of the pth unique Rouse mode of a star polymer varies as (2Na + 1)2/p2. Since alternate Rouse modes in a star polymer have a multiplicity of f-1, they add to the terminal modulus of the star polymers and the terminal modulus, G(tau) ends up being proportional to f-1 (besides being inversely proportional to N, which is also the case with linear polymers). A self-consistent theory for the relaxation of entangled star polymers was developed based on the work done by Colby and Rubinstein on linear blends. This theory considers the duality of relaxation dynamics (direct stress relaxation and indirect relaxation by release of constraints) and models the relaxation due to constraint release R(t) based on Dean's approach in solving the vibration frequencies of glassy chains with random spring constants. In our case, the mobilities of beads were considered to be random and based on the relative weight of the prefactor of a Maxwell function, a group of which was fitted to the stress relaxation function mu(t) of a star polymer (proposed and derived by Doi). The tube dilation model for star and comb polymers was investigated in detail and predictions compared to rheological data from polypropylene, polybutadiene and polystyrene comb polymers along with PEP star polymers. The relaxation time from the Tube Dilation Model was compared with the classical Tube Model and was shown to have an extra power dependence on the fraction of the comb backbone.

  18. Initial Experience Using Closed Incision Negative Pressure Therapy after Immediate Postmastectomy Breast Reconstruction

    PubMed Central

    Sigalove, Steven R.; Maxwell, G. Patrick

    2016-01-01

    Summary: Although immediate postmastectomy breast reconstruction is favored over delayed reconstruction, it remains associated with high complication rates. Potential complications include seroma formation, dehiscence, infection, and tissue necrosis along incision edges. Closed incision negative pressure therapy (ciNPT; Prevena Incision Management System, KCI, an Acelity company, San Antonio, Tex.) has been reported to help hold incision edges together, protect incisions from external contamination, and remove fluid and infectious material. We investigated outcomes of applying ciNPT with a customizable dressing over closed incisions in 13 patients (25 breasts) who received immediate postmastectomy reconstruction as part of 2-stage expander/implant breast reconstruction. Nipple-sparing mastectomy was performed on 14 breasts, reduction-pattern mastectomy on 6 breasts, and skin-sparing mastectomy on 5 breasts. All breasts had ciNPT with a customizable dressing applied over the entire clean closed incision immediately after surgery at −125 mmHg for an average of 4.3 days. At 3-month follow-up, 24 of the 25 (96%) breasts had achieved healing. Delayed hematoma occurred on postoperative day 13 in 1 breast in the nipple-sparing mastectomy group and resolved. In the reduction-pattern mastectomy group, superficial dehiscence occurred on 3 breasts and resolved with local wound care. One breast in that group developed flap necrosis requiring surgical revision. Less drainage was observed in attached closed-suction drains, so time to drain removal was reduced from an estimated average of 12–14 days to 8.2 days. Based on the initial experience in this study, larger studies are warranted to evaluate the use of ciNPT with customizable or peel-and-place dressings after immediate postmastectomy breast reconstruction. PMID:27536498

  19. Cephalad-caudad versus transverse blunt expansion of the low transverse uterine incision during cesarean delivery.

    PubMed

    Xodo, Serena; Saccone, Gabriele; Cromi, Antonella; Ozcan, Pinar; Spagnolo, Emanuela; Berghella, Vincenzo

    2016-07-01

    It is imperative to have evidence-based guidelines for cesarean delivery. The aim of this meta-analysis was to evaluate the effectiveness of a cephalad-caudad compared to transverse blunt expansion of the uterine incision to reduce blood loss in women who underwent low-segment transverse cesarean delivery. We therefore performed a systematic search in electronic databases from their inception until March 2016. We included all randomized trials comparing cephalad-caudad versus transverse (control group) blunt expansion of the uterine incision in women who underwent a low transverse cesarean delivery. The primary outcome was postpartum blood loss, defined as the mean amount of blood loss (mL). Two trials (921 women) were analyzed. After the transverse uterine incision in the lower uterine segment with the scalpel, the uterine incision was then bluntly expanded by the designated method. Blunt expansion of the primary incision was derived by placing the index fingers of the operating surgeon into the incision and pulling the fingers apart laterally (transverse group) or cephalad (cephalad-caudad group). Women who were randomized in the cephalad-caudad group had lower: mean of postpartum blood loss, hemoglobin drop and hematocrit drop 24h after cesarean, unintended extension, uterine vessels injury, blood loss >1500mL and need for additional stitches. There was no statistically significant difference in the incidence of blood loss >1000mL, in the operating time and in post-operative pain. In conclusion, expansion of the uterine incision with fingers in a cephalad-caudad direction is associated with better maternal outcomes and, therefore, should be preferred to transverse expansion during a cesarean delivery. PMID:27180273

  20. Trochlear Nerve Schwannoma Treated with Gamma Knife after Excision: A Case Report and Review of the Literature

    PubMed Central

    Inoue, Takuro; Shima, Ayako; Hirai, Hisao; Suzuki, Fumio; Matsuda, Masayuki

    2015-01-01

    Trochlear nerve schwannomas are extremely rare. We present a surgically excised case of trochlear nerve schwannoma followed by Gamma Knife (ELEKTA, Stockholm, Sweden) after histologic confirmation. A 52-year-old man presented with diplopia, gait disturbance, and sensory disturbance. Magnetic resonance imaging demonstrated a large cystic mass at ambient cistern on the right side. Subtotal excision followed by Gamma Knife surgery was undertaken. His neurologic symptoms disappeared with radiologic reduction in size at 15-month follow-up. Because Gamma Knife can manage trochlear nerve schwannomas well, surgical excision should be reserved for large ones and limited to subcapsular or subtotal removal with the expectation of possible recovery of neurologic dysfunction. PMID:26623236

  1. SU-E-T-536: Inhomogeneity Correction in Planning of Gamma Knife Treatments for Acoustic Schwannoma

    SciTech Connect

    Lu, L; Gupta, N; Hessler, J; Liu, A; Weldon, M; McGregor, J; Ammirati, M; Guiou, M; Xia, F; Grecula, J

    2014-06-01

    Purpose: To find out the dose difference on targets and organs at risk for the treatment of acoustic schwannoma if the inhomogeneity correction (Convolution algorithm) is applied. Methods: Images of patients treated for acoustic schwannoma with Gamma Knife using TMR 10 algorithm were retrieved from database and replanned with Convolution and TMR 10 algorithm respectively. These patients were treated using a preplan scheme in following: (1) Before the actual treatment day, using the MRI image that was taken without a head frame on the patient's skull, a pre-treatment plan was made based on the default skull coordinates in the Gamma Knife treatment planning system (LGP); (2) then on treatment day, a head frame was placed on the patient's skull, and a CT image was taken. The CT image with head frame was registered and fused with the completed preplan; (3) the treatment plan was finalized and the treatment was delivered. To find out the dosimetry impact of inhomogeneity correction, we used the retrieved CT images to replan the treatment using Convolution algorithm in LGP software version 10.1.1. The dose distributions and the dose volume histograms for targets and OARs were compared for these two dose calculation algorithms. Results: The dose calculated with the Convolution algorithm in general is slightly lower than the one from TMR 10 around the boney area. The effect from the inhomogeneity correction is observable but not significant, and varies with the location of the tumor. Conclusion: Inhomogeneity correction slightly improve the dose accuracy for acoustic schwannoma Gamma Knife treatments although the correction may not be very significant. Our Result provides evidence for dose prescription adjustment to treat acoustic schwannoma. The actual clinical outcome of switching from using TMR10 to using Convolution needs to be further investigated.

  2. Clinical Evaluation of Targeting Accuracy of Gamma Knife Radiosurgery in Trigeminal Neuralgia

    SciTech Connect

    Massager, Nicolas Abeloos, Laurence; Devriendt, Daniel; Op de Beeck, Marc; Levivier, Marc

    2007-12-01

    Purpose: The efficiency of radiosurgery is related to its highly precise targeting. We assessed clinically the targeting accuracy of radiosurgical treatment with the Leksell Gamma Knife for trigeminal neuralgia. We also studied the applied radiation dose within the area of focal contrast enhancement on the trigeminal nerve root following radiosurgery. Methods and Materials: From an initial group of 78 patients with trigeminal neuralgia treated with gamma knife radiosurgery using a 90-Gy dose, we analyzed a subgroup of 65 patients for whom 6-month follow-up MRI showed focal contrast enhancement of the trigeminal nerve. Follow-up MRI was spatially coregistered to the radiosurgical planning MRI. Target accuracy was assessed from deviation of the coordinates of the intended target compared with the center of enhancement on postoperative MRI. Radiation dose delivered at the borders of contrast enhancement was evaluated. Results: The median deviation of the coordinates between the intended target and the center of contrast enhancement was 0.91 mm in Euclidean space. The radiation doses fitting within the borders of the contrast enhancement of the trigeminal nerve root ranged from 49 to 85 Gy (median value, 77 {+-} 8.7 Gy). Conclusions: The median deviation found in clinical assessment of gamma knife treatment for trigeminal neuralgia is low and compatible with its high rate of efficiency. Focal enhancement of the trigeminal nerve after radiosurgery occurred in 83% of our patients and was not associated with clinical outcome. Focal enhancement borders along the nerve root fit with a median dose of 77 {+-} 8.7 Gy.

  3. Implementation of Monte Carlo Dose calculation for CyberKnife treatment planning

    NASA Astrophysics Data System (ADS)

    Ma, C.-M.; Li, J. S.; Deng, J.; Fan, J.

    2008-02-01

    Accurate dose calculation is essential to advanced stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT) especially for treatment planning involving heterogeneous patient anatomy. This paper describes the implementation of a fast Monte Carlo dose calculation algorithm in SRS/SRT treatment planning for the CyberKnife® SRS/SRT system. A superposition Monte Carlo algorithm is developed for this application. Photon mean free paths and interaction types for different materials and energies as well as the tracks of secondary electrons are pre-simulated using the MCSIM system. Photon interaction forcing and splitting are applied to the source photons in the patient calculation and the pre-simulated electron tracks are repeated with proper corrections based on the tissue density and electron stopping powers. Electron energy is deposited along the tracks and accumulated in the simulation geometry. Scattered and bremsstrahlung photons are transported, after applying the Russian roulette technique, in the same way as the primary photons. Dose calculations are compared with full Monte Carlo simulations performed using EGS4/MCSIM and the CyberKnife treatment planning system (TPS) for lung, head & neck and liver treatments. Comparisons with full Monte Carlo simulations show excellent agreement (within 0.5%). More than 10% differences in the target dose are found between Monte Carlo simulations and the CyberKnife TPS for SRS/SRT lung treatment while negligible differences are shown in head and neck and liver for the cases investigated. The calculation time using our superposition Monte Carlo algorithm is reduced up to 62 times (46 times on average for 10 typical clinical cases) compared to full Monte Carlo simulations. SRS/SRT dose distributions calculated by simple dose algorithms may be significantly overestimated for small lung target volumes, which can be improved by accurate Monte Carlo dose calculations.

  4. Verification of Gamma Knife extend system based fractionated treatment planning using EBT2 film

    SciTech Connect

    Natanasabapathi, Gopishankar; Bisht, Raj Kishor

    2013-12-15

    Purpose: This paper presents EBT2 film verification of fractionated treatment planning with the Gamma Knife (GK) extend system, a relocatable frame system for multiple-fraction or serial multiple-session radiosurgery.Methods: A human head shaped phantom simulated the verification process for fractionated Gamma Knife treatment. Phantom preparation for Extend Frame based treatment planning involved creating a dental impression, fitting the phantom to the frame system, and acquiring a stereotactic computed tomography (CT) scan. A CT scan (Siemens, Emotion 6) of the phantom was obtained with following parameters: Tube voltage—110 kV, tube current—280 mA, pixel size—0.5 × 0.5 and 1 mm slice thickness. A treatment plan with two 8 mm collimator shots and three sectors blocking in each shot was made. Dose prescription of 4 Gy at 100% was delivered for the first fraction out of the two fractions planned. Gafchromic EBT2 film (ISP Wayne, NJ) was used as 2D verification dosimeter in this process. Films were cut and placed inside the film insert of the phantom for treatment dose delivery. Meanwhile a set of films from the same batch were exposed from 0 to 12 Gy doses for calibration purposes. An EPSON (Expression 10000 XL) scanner was used for scanning the exposed films in transparency mode. Scanned films were analyzed with inhouse written MATLAB codes.Results: Gamma index analysis of film measurement in comparison with TPS calculated dose resulted in high pass rates >90% for tolerance criteria of 1%/1 mm. The isodose overlay and linear dose profiles of film measured and computed dose distribution on sagittal and coronal plane were in close agreement.Conclusions: Through this study, the authors propose treatment verification QA method for Extend frame based fractionated Gamma Knife radiosurgery using EBT2 film.

  5. Spin relaxation in disordered media

    NASA Astrophysics Data System (ADS)

    Dzheparov, F. S.

    2011-10-01

    A review is given on theoretical grounds and typical experimental appearances of spin dynamics and relaxation in solids containing randomly distributed nuclear and/or electronic spins. Brief content is as follows. Disordered and magnetically diluted systems. General outlines of the spin transport theory. Random walks in disordered systems (RWDS). Observable values in phase spin relaxation, free induction decay (FID). Interrelation of longitudinal and transversal relaxation related to dynamics of occupancies and phases. Occupation number representation for equations of motion. Continuum media approximation and inapplicability of moment expansions. Long-range transitions vs percolation theory. Concentration expansion as a general constructive basis for analytical methods. Scaling properties of propagators. Singular point. Dynamical and kinematical memory in RWDS. Ways of regrouping of concentration expansions. CTRW and semi-phenomenology. Coherent medium approximation for nuclear relaxation via paramagnetic impurities. Combining of memory functions and cumulant expansions for calculation of FID. Path integral representations for RWDS. Numerical simulations of RWDS. Spin dynamics in magnetically diluted systems with low Zeeman and medium low dipole temperatures. Cluster expansions, regularization of dipole interactions and spectral dynamics.

  6. Theory of nuclear magnetic relaxation

    NASA Technical Reports Server (NTRS)

    Mcconnell, J.

    1983-01-01

    A theory of nuclear magnetic interaction is based on the study of the stochastic rotation operator. The theory is applied explicitly to relaxation by anisotropic chemical shift and to spin-rotational interactions. It is applicable also to dipole-dipole and quadrupole interactions.

  7. NMR Relaxation and Petrophysical Properties

    NASA Astrophysics Data System (ADS)

    Fleury, Marc

    2011-03-01

    NMR relaxation is routinely used in the field of geosciences to give basic petrophysical properties such as porosity, pore size distribution, saturation etc. In this tutorial, we focus on the pore size distribution deduced from NMR. We recall the basic principle used in the interpretation of the NMR signal and compare the results with other standard petrophysical techniques such as mercury pore size distribution, BET specific surface measurements, thin section visualizations. The NMR pore size distribution is a unique information available on water saturated porous media and can give similar results as MICP in certain situations. The scaling of NMR relaxation time distribution (s) into pore sizes (μm) requires the knowledge of the surface relaxivity (μm/s) and we recommend using specific surface measurements as an independent determination of solid surface areas. With usual surface relaxivities, the NMR technique can explore length-scales starting from nano-meters and ending around 100 μm. Finally, we will introduce briefly recent techniques sensitive to the pore to pore diffusional exchange, providing new information on the connectivity of the pore network, but showing another possibility of discrepancy in the determination of pore size distribution with standard techniques.

  8. Distributed Relaxation for Conservative Discretizations

    NASA Technical Reports Server (NTRS)

    Diskin, Boris; Thomas, James L.

    2001-01-01

    A multigrid method is defined as having textbook multigrid efficiency (TME) if the solutions to the governing system of equations are attained in a computational work that is a small (less than 10) multiple of the operation count in one target-grid residual evaluation. The way to achieve this efficiency is the distributed relaxation approach. TME solvers employing distributed relaxation have already been demonstrated for nonconservative formulations of high-Reynolds-number viscous incompressible and subsonic compressible flow regimes. The purpose of this paper is to provide foundations for applications of distributed relaxation to conservative discretizations. A direct correspondence between the primitive variable interpolations for calculating fluxes in conservative finite-volume discretizations and stencils of the discretized derivatives in the nonconservative formulation has been established. Based on this correspondence, one can arrive at a conservative discretization which is very efficiently solved with a nonconservative relaxation scheme and this is demonstrated for conservative discretization of the quasi one-dimensional Euler equations. Formulations for both staggered and collocated grid arrangements are considered and extensions of the general procedure to multiple dimensions are discussed.

  9. Ellipsoidal relaxation of electrodeformed vesicles

    NASA Astrophysics Data System (ADS)

    Yu, Miao; Lin, Hao; Lira, Rafael; Dimova, Rumiana; Riske, Karin

    2015-11-01

    Electrodeformation has been extensively applied to investigate the mechanical behavior of vesicles and cells. While the deformation process often exhibits complex behavior and reveals interesting physics, the relaxation process post-pulsation is equally intriguing yet less frequently studied. In this work theoretical analysis and experimental quantification on the ellipsoidal relaxation of vesicles are presented, which reveal the simplicity and universal aspects of this process. The Helfrich formula, which is derived only for equilibrated shapes, is shown to be applicable to dynamic situations such as in relaxation. A closed-form solution is derived which predicts the vesicle aspect ratio as a function of time. Scattered data are unified by a timescale, which leads to a similarity behavior, governed by a distinctive solution for each vesicle type. Two separate regimes in the relaxation are identified, namely, the ``entropic'' and the ``constant-tension'' regime. The bending rigidity and the initial membrane tension can be simultaneously extracted from the data/model analysis, posing the current approach as an effective means for the mechanical analysis of biomembranes.

  10. Choosing a skeletal muscle relaxant.

    PubMed

    See, Sharon; Ginzburg, Regina

    2008-08-01

    Skeletal muscle relaxants are widely used in treating musculoskeletal conditions. However, evidence of their effectiveness consists mainly of studies with poor methodologic design. In addition, these drugs have not been proven to be superior to acetaminophen or nonsteroidal anti-inflammatory drugs for low back pain. Systematic reviews and meta-analyses support using skeletal muscle relaxants for short-term relief of acute low back pain when nonsteroidal anti-inflammatory drugs or acetaminophen are not effective or tolerated. Comparison studies have not shown one skeletal muscle relaxant to be superior to another. Cyclobenzaprine is the most heavily studied and has been shown to be effective for various musculoskeletal conditions. The sedative properties of tizanidine and cyclobenzaprine may benefit patients with insomnia caused by severe muscle spasms. Methocarbamol and metaxalone are less sedating, although effectiveness evidence is limited. Adverse effects, particularly dizziness and drowsiness, are consistently reported with all skeletal muscle relaxants. The potential adverse effects should be communicated clearly to the patient. Because of limited comparable effectiveness data, choice of agent should be based on side-effect profile, patient preference, abuse potential, and possible drug interactions. PMID:18711953

  11. Relaxation properties in classical diamagnetism

    NASA Astrophysics Data System (ADS)

    Carati, A.; Benfenati, F.; Galgani, L.

    2011-06-01

    It is an old result of Bohr that, according to classical statistical mechanics, at equilibrium a system of electrons in a static magnetic field presents no magnetization. Thus a magnetization can occur only in an out of equilibrium state, such as that produced through the Foucault currents when a magnetic field is switched on. It was suggested by Bohr that, after the establishment of such a nonequilibrium state, the system of electrons would quickly relax back to equilibrium. In the present paper, we study numerically the relaxation to equilibrium in a modified Bohr model, which is mathematically equivalent to a billiard with obstacles, immersed in a magnetic field that is adiabatically switched on. We show that it is not guaranteed that equilibrium is attained within the typical time scales of microscopic dynamics. Depending on the values of the parameters, one has a relaxation either to equilibrium or to a diamagnetic (presumably metastable) state. The analogy with the relaxation properties in the Fermi Pasta Ulam problem is also pointed out.

  12. "Stressing" Relaxation in the Classroom.

    ERIC Educational Resources Information Center

    Prager-Decker, Iris

    A rationale is offered for incorporating relaxation training in elementary school classroom activities. Cited are research studies which focus on the reaction of children to stressful life changes and resulting behavioral and physical disorders. A list is given of significant life events which may be factors in causing diseases or misbehavior in…

  13. Relaxation times estimation in MRI

    NASA Astrophysics Data System (ADS)

    Baselice, Fabio; Caivano, Rocchina; Cammarota, Aldo; Ferraioli, Giampaolo; Pascazio, Vito

    2014-03-01

    Magnetic Resonance Imaging is a very powerful techniques for soft tissue diagnosis. At the present, the clinical evaluation is mainly conducted exploiting the amplitude of the recorded MR image which, in some specific cases, is modified by using contrast enhancements. Nevertheless, spin-lattice (T1) and spin-spin (T2) relaxation times can play an important role in many pathology diagnosis, such as cancer, Alzheimer or Parkinson diseases. Different algorithms for relaxation time estimation have been proposed in literature. In particular, the two most adopted approaches are based on Least Squares (LS) and on Maximum Likelihood (ML) techniques. As the amplitude noise is not zero mean, the first one produces a biased estimator, while the ML is unbiased but at the cost of high computational effort. Recently the attention has been focused on the estimation in the complex, instead of the amplitude, domain. The advantage of working with real and imaginary decomposition of the available data is mainly the possibility of achieving higher quality estimations. Moreover, the zero mean complex noise makes the Least Square estimation unbiased, achieving low computational times. First results of complex domain relaxation times estimation on real datasets are presented. In particular, a patient with an occipital lesion has been imaged on a 3.0T scanner. Globally, the evaluation of relaxation times allow us to establish a more precise topography of biologically active foci, also with respect to contrast enhanced images.

  14. Climate-sensitive feedbacks between hillslope processes and fluvial erosion in sediment-driven incision models

    NASA Astrophysics Data System (ADS)

    Skov, Daniel S.; Egholm, David L.

    2016-04-01

    Surface erosion and sediment production seem to have accelerated globally as climate cooled in the Late Cenozoic, [Molnar, P. 2004, Herman et al 2013]. Glaciers emerged in many high mountain ranges during the Quaternary, and glaciation therefore represents a likely explanation for faster erosion in such places. Still, observations and measurements point to increases in erosion rates also in landscapes where erosion is driven mainly by fluvial processes [Lease and Ehlers (2013), Reusser (2004)]. Flume experiments and fieldwork have shown that rates of incision are to a large degree controlled by the sediment load of streams [e.g. Sklar and Dietrich (2001), Beer and Turowski (2015)]. This realization led to the formulation of sediment-flux dependent incision models [Sklar and Dietrich (2004)]. The sediment-flux dependence links incision in the channels to hillslope processes that supply sediment to the channels. The rates of weathering and soil transport on the hillslopes are processes that are likely to respond to changing temperatures, e.g. because of vegetation changes or the occurrence of frost. In this study, we perform computational landscape evolution experiments, where the coupling between fluvial incision and hillslope processes is accounted for by coupling a sediment-flux-dependent model for fluvial incision to a climate-dependent model for weathering and hillslope sediment transport. The computational experiments first of all demonstrate a strong positive feedback between channel and hillslope processes. In general, faster weathering leads to higher rates of channel incision, which further increases the weathering rates, mainly because of hillslope steepening. Slower weathering leads to the opposite result. The experiments also demonstrate, however, that the feedbacks vary significantly between different parts of a drainage network. For example, increasing hillslope sediment production may accelerate incision in the upper parts of the catchment, while at

  15. Randomized, Clinical Trial on Diathermy and Scalpel Incisions in Elective General Surgery

    PubMed Central

    Talpur, Altaf Ahmed; Khaskheli, Abdul Basir; Kella, Nandlal; Jamal, Akmal

    2015-01-01

    Background: Since a long time skin incisions have routinely been made with scalpels. Now a day there is a shift in trend from this method to electrosurgical skin incisions. However, fear of bad scars and improper wound healing has prevented its wide spread use. This Study aimed to compare both methods of skin incisions for different variables. Objectives: The aim of this study was to examine incisional time, blood loss during incision and postoperative wound complications and pain with both methods of skin incision. Patients and Methods: A prospective, comparative and randomized study was conducted at different hospitals of Hyderabad and Nawabshah, Pakistan from 1st of December 2009 to 30th of November 2011. The study included patients of either sex above the age of five years with general surgical pathology who were to undergo surgery. these candidates were randomly put into two groups. In Group A patients incision was made with a scalpel and in group B with diathermy. Data was analyzed for age, sex, comorbid illness, incisional time, blood loss during incision making and postoperative pain and wound complications. Results: A total of 283 patients completed the follow-up and were included in the final analysis. Group A comprised of 143 (50.53%) patients; 83 (58%) males and 60 (42%) females with a mean age of 36.03 years. Amongst the 140 patients of group B, there were 85 (60.7%) males and 55 (39.3%) females with a mean age of 36.52 years. Twenty-five (17.48%) patients of group A and 27 (19.28%) of group B had comorbid illnesses. Mean incision time was 8.9025-sec/cm2 for group A and 7.3057 sec/cm2 for group B patients. Mean blood loss during incision making was 1.8262 mL/cm2 and 1.1346 mL/cm2 for group A and B patients, respectively. Pain was 5.2957 for group A patients on day one and 3.1181 for group B patients. Pain score was 2.1049 and 1.6206 on day two and 0.8191 and 0.7192 on day five, for group A and B patients, respectively. Postoperative wound complications

  16. Fractionated Stereotactic Gamma Knife Radiosurgery for Medial Temporal Lobe Epilepsy: A Case Report.

    PubMed

    Park, Hye Ran; Chung, Hyun-Tai; Lee, Sang Kun; Kim, Dong Gyu; Paek, Sun Ha

    2016-04-01

    An 18-year-old left-handed male harbored intractable medial temporal lobe epilepsy (MTLE) underwent fractionated gamma knife surgery (GKS) instead of open surgery, considering the mental retardation and diffuse cerebral dysfunction. GKS treatment parameters were: target volume, 8.8 cm(3); total marginal dose, 24 Gy in 3 fractionations at the 50% isodose line. The patient has been free from seizures since 9 months after GKS, with notable improvement in cognitive outcome. Fractionated GKS could be considered as a safe tool for seizure control and neuropsychological improvement in patients with MTLE. PMID:27122996

  17. Benchmark Experiment of Dose Rate Distributions Around the Gamma Knife Medical Apparatus

    SciTech Connect

    Oishi, K.; Kosako, K.; Kobayashi, Y.; Sonoki, I.

    2014-06-15

    Dose rate measurements around a gamma knife apparatus were performed by using an ionization chamber. Analyses have been performed by using the Monte Carlo code MCNP-5. The nuclear library used for the dose rate distribution of {sup 60}Co was MCPLIB04. The calculation model was prepared with a high degree of fidelity, such as the position of each Cobalt source and shielding materials. Comparisons between measured results and calculated ones were performed, and a very good agreement was observed. It is concluded that the Monte Carlo calculation method with its related nuclear data library is very effective for such a complicated radiation oncology apparatus.

  18. Benchmark Experiment of Dose Rate Distributions Around the Gamma Knife Medical Apparatus

    NASA Astrophysics Data System (ADS)

    Oishi, K.; Kosako, K.; Kobayashi, Y.; Sonoki, I.

    2014-06-01

    Dose rate measurements around a gamma knife apparatus were performed by using an ionization chamber. Analyses have been performed by using the Monte Carlo code MCNP-5. The nuclear library used for the dose rate distribution of 60Co was MCPLIB04. The calculation model was prepared with a high degree of fidelity, such as the position of each Cobalt source and shielding materials. Comparisons between measured results and calculated ones were performed, and a very good agreement was observed. It is concluded that the Monte Carlo calculation method with its related nuclear data library is very effective for such a complicated radiation oncology apparatus.

  19. Phantom Positioning Variation in the Gamma Knife® Perfexion Dosimetry

    NASA Astrophysics Data System (ADS)

    Costa, N. A.; Potiens, M. P. A.; Saraiva, C. W. C.

    2016-07-01

    The use of small volume ionization chamber has become required for the dosimetry of equipments that use small radiation fields such as the Gamma Knife® Perfexion (GKP) unit. In this work, a pinpoint ionization chamber was inserted into the dosimetry phantom and measurements were performed with the phantom in different positions, in order to verify if the change in the phantom positioning affects the dosimetry of the GKP. Four different phantom positions were performed. The variation in the result is within the range allowed for the dosimetry of a GKP equipment.

  20. Fractionated Stereotactic Gamma Knife Radiosurgery for Medial Temporal Lobe Epilepsy: A Case Report

    PubMed Central

    Park, Hye Ran; Chung, Hyun-Tai; Lee, Sang Kun; Kim, Dong Gyu

    2016-01-01

    An 18-year-old left-handed male harbored intractable medial temporal lobe epilepsy (MTLE) underwent fractionated gamma knife surgery (GKS) instead of open surgery, considering the mental retardation and diffuse cerebral dysfunction. GKS treatment parameters were: target volume, 8.8 cm3; total marginal dose, 24 Gy in 3 fractionations at the 50% isodose line. The patient has been free from seizures since 9 months after GKS, with notable improvement in cognitive outcome. Fractionated GKS could be considered as a safe tool for seizure control and neuropsychological improvement in patients with MTLE. PMID:27122996

  1. Mathematical model parameters for describing the particle size spectra of knife-milled corn stover

    SciTech Connect

    Bitra, V.S.P; Womac, A.R.; Yang, Y.T.; Miu, P.I.; Igathanathane, C.

    2009-09-01

    Particle size distributions of Corn stover (Zea mays L.) created by a knife mill were determined using integral classifying screens with sizes from 12.7 to 50.8 mm, operating at speeds from 250 to 500 rpm, and mass input rates ranging from 1 to 9 kg min_1. Particle distributions were classified using American Society of Agricultural and Biological Engineers (ASABE) standardised sieves for forage analysis that incorporated a horizontal sieving motion. The sieves were made from machined-aluminium with their thickness proportional to the sieve opening dimensions. A wide range of analytical descriptors that could be used to mathematically represent the range of particle sizes in the distributions were examined. The correlation coefficients between geometric mean length and screen size, feed rate, and speed were 0.980, 0.612, and _0.027, respectively. Screen size and feed rate directly influenced particle size, whereas operating speed had a weak indirect relation with particle size. The Rosin Rammler equation fitted the chopped corn stover size distribution data with coefficient of determination (R2) > 0.978. This indicated that particle size distribution of corn stover was well-fit by the Rosin Rammler function. This can be attributed to the fact that Rosin Rammler expression was well suited to the skewed distribution of particle sizes. Skewed distributions occurred when significant quantities of particles, either finer or coarser, existed or were removed from region of the predominant size. The mass relative span was slightly greater than 1, which indicated that it was a borderline narrow to wide distribution of particle sizes. The uniformity coefficient was <4.0 for 19.0 50.8 mm screens, which indicated particles of relatively uniform size. Knife mill chopping of corn stover produced fine-skewed mesokurtic particles with 12.7 50.8 mm screens. Size-related parameters, namely, geometric mean length, Rosin Rammler size parameter, median length, effective length, and

  2. Radiation shielding evaluation based on five years of data from a busy CyberKnife center.

    PubMed

    Yang, Jun; Feng, Jing

    2014-01-01

    We examined the adequacy of existing shielding guidelines using five-year clinical data from a busy CyberKnife center. From June 2006 through July 2011, 1,370 patients were treated with a total of 4,900 fractions and 680,691 radiation beams using a G4 CyberKnife. Prescription dose and total monitor units (MU) were analyzed to estimate the shielding workload and modulation factor. In addition, based on the beam's radiation source position, targeting position, MU, and beam collimator size, the MATLAB program was used to project each beam toward the shielding barrier. The summation of the projections evaluates the distribution of the shielding load. On average, each patient received 3.6 fractions, with an average 9.1 Gy per fraction prescribed at the 71.1% isodose line, using 133.7 beams and 6,200 MU. Intracranial patients received an average of 2.7 fractions, with 8.6 Gy per fraction prescribed at the 71.4% isodose line, using 133 beams and 5,083 MU. Extracranial patients received an average of 3.94 fractions, with 9.2 Gy per frac- tion prescribed at the 71% isodose line, using 134 beams and 6,514 MU. Most- used collimator sizes for intracranial patients were smaller (7.5 to 20 mm) than for extracranial patients (20 to 40 mm). Eighty-five percent of the beams exited through the floor, and about 40% of the surrounding wall area received no direct beam. For the rest of the wall, we found "hot" areas that received above-average MU. The locations of these areas were correlated with the projection of the nodes for extracranial treatments. In comparison, the beam projections on the wall were more spread for intracranial treatments. The maximum MU any area received from intracranial treatment was less than 0.25% of total MU used for intracranial treatments, and was less than 1.2% of total MU used for extracranial treatments. The combination of workload, modulation factor, and use factor in our practice are about tenfold less than recommendations in the existing CyberKnife

  3. X-ray Phase Imaging Microscopy with Two-Dimensional Knife-Edge Filters

    NASA Astrophysics Data System (ADS)

    Choi, Jaeho; Park, Yong-Sung

    2012-04-01

    A novel scheme of X-ray differential phase imaging was implemented with an array source and a two-dimensional Foucault knife-edge (2DFK). A pinhole array lens was employed to manipulate the X-ray beam on the Fourier space. An emerging biaxial scanning procedure was also demonstrated with the periodic 2DFK. The differential phase images (DPIs) of the midrib in a leaf of a rose bush were visualized to verify the phase imaging of biological specimens by the proposed method. It also has features of depicting multiple-stack phase images, and rendering morphological DPIs, because it acquires pure phase information.

  4. C-shaped Incision for Far-Lateral Suboccipital Approach: Anatomical Study and Clinical Correlation.

    PubMed

    Lau, Tsz; Reintjes, Stephen; Olivera, Raul; van Loveren, Harry R; Agazzi, Siviero

    2015-03-01

    Background The standard incision for far-lateral suboccipital approaches has been the classic "reverse hockey stick." Although that incision provides ample exposure, concern has been raised that excessive muscle dissection and skin elevation might lead to accumulation of cerebrospinal fluid (CSF) under the flap with increased risk of CSF leak. We hypothesize that the C-shaped incision can minimize the amount of muscle dissection and provide optimal exposure and surgical outcomes. Objective To describe the anatomical dissection for the C-shaped incision and clinical application of the C-shaped incision for the far-lateral approach. Methods A retrospective analysis of all the patients operated on at our center using this approach for the treatment of aneurysm of the posterior inferior cerebellar artery (PICA) from 2005 to 2011. Results of clinical and operative outcome are evaluated. Surgical techniques are described in detail. Cadaveric dissections using the C-shaped incision were performed to assess the exposure of the far-lateral suboccipital area. Results Eleven consecutive patients who had undergone this procedure were selected. All patients underwent clipping of PICA aneurysms. Nine patients (82%) presented with ruptured aneurysms and subarachnoid hemorrhage. All of them underwent suboccipital craniectomy and C1 laminectomy. The dura mater was closed in a watertight fashion in 10 patients (91%). No CSF leak or pseudomeningocele were reported. In nine SAH patients, two (22%) had postoperative dysphagia and required long-term percutaneous endoscopic gastrostomy tube placement. One patient (11%) had chronic respiratory failure and required a tracheostomy. Three patients (33%) developed hydrocephalus and required a ventriculoperitoneal shunt. Conclusions The C-shaped incision is a valid alternative to the classic reverse hockey-stick incision to gain exposure for far-lateral craniotomies. Knowing the anatomy and dissection techniques can provide an easy

  5. Controls on aggradation and incision in the NE Negev, Israel, since the middle Pleistocene

    NASA Astrophysics Data System (ADS)

    Matmon, A.; Elfassi, S.; Hidy, A.; Geller, Y.; Porat, N.

    2016-05-01

    We investigated the mid-Pleistocene to recent aggradation-incision pattern of two drainage systems (Nahal Peres and Nahal Tahmas) in the hyperarid north eastern Negev desert, southern Israel. Although these drainage systems drain into the tectonically active Dead Sea basin, lake level fluctuations cannot account for the aggradation-incision pattern as bedrock knickpoints disconnect the investigated parts of these drainage systems from base level influence. We applied geomorphic mapping, soil stratigraphy, optically stimulated luminescence (OSL) and cosmogenic (in situ 10Be) exposure dating to reconstruct cycles of aggradation and incision of alluvial terraces and to study their temporal association with regional periods of humidity and aridity and global glacial-interglacial cycles. The spatial and temporal relationships between the alluvial units suggest changes in the drainage system behavior since the middle Pleistocene, and show a pattern in which prolonged periods of sediment aggradation alternated with short periods of rapid and intense degradation through erosion and incision into sediment and bedrock. We obtain ages for several Pleistocene-Holocene periods of incision: ~ 1.1 Ma, ~ 300 ka, ~ 120 ka, ~ 20 ka, ~ 12 ka and ~ 2 ka. Although broadly synchronous, the Nahal Peres and Nahal Tahmas systems exhibit temporal differences in aggradation and incision. Hyperarid conditions have persisted in the region at least since the middle Pleistocene, as evidenced by gypsic-salic soils that ubiquitously cap the investigated alluvial terraces. This observation is consistent with other observations throughout the Negev indicating prolonged aridity. Thus, alternation between sediment aggradation and degradation cannot be correlated in a simple and straightforward way to climatic changes. We explain the temporal differences in aggradation and incision between Nahal Peres and Nahal Tahmas as resulting from the differences in stream gradient, basin hypsometry, and drainage

  6. The role of sideport incision in astigmatism change after cataract surgery

    PubMed Central

    Theodoulidou, Sofia; Asproudis, Ioannis; Kalogeropoulos, Christos; Athanasiadis, Aristidis; Aspiotis, Miltiadis

    2015-01-01

    Purpose To study the changes in corneal astigmatism after cataract surgery when the sideport incision is performed at a predetermined location away from the tunnel incision. Setting General Hospital of Piraeus “Tzaneio”, Attiki, Greece. Materials and methods A total of 333 eyes with corneal astigmatism ≤1.5 diopters (D) underwent cataract surgery. A three-step superotemporal clear corneal incision for the right eye and a superonasal clear corneal incision for the left eye (3.0 mm) was made, while the sideport incision was located at <90°, 90°–110°, and >110°. Keratometric data were measured with corneal topography EyeSys Vista 2000 pre- and postoperatively at the 1st and 6th month. Surgically induced astigmatism was calculated by vector analysis. We noted all cases in which a change >0.5 D in corneal astigmatic power occurred, as well as a change >20° in axis torque, despite axis direction. Results After multiple logistic regression analysis was conducted, cases with >110° distance between the tunnel and sideport incision had 2.22 times (P=0.021) greater likelihood for having changed >0.5 D in astigmatic power at the 1st month and 3.45 times (P=0.031) at the 6th month postoperatively, as compared with cases with a 90°–110° distance between the tunnel and sideport incision. As for the change in the astigmatic axis, cases with <90° distance had a 4.18 times greater likelihood for having a change >20° (P<0.001) (preoperative to 1st month) as compared with cases having 90°–110° of distance. Conclusion For surgeons that operate only from the superior position, we propose that in order to produce an incision that is as “astigmatically neutral” as possible, they should perform the sideport incision at a 90°–110° distance. PMID:26346741

  7. Transurethral optical laser knife and probe director for lateral firing laser probes

    NASA Astrophysics Data System (ADS)

    Malek, Reza S.

    1993-05-01

    Laser energy has been used by many for transurethral incision of small, obstructive prostates, vesical neck contractures, and urethral strictures. The customary techniques of moving the tip of the laser fiber through a cystoscope with a conventional laser guide, almost tangentially to the tissue to be incised, or drilling radially arranged holes in the scar, or both, have been cumbersome and imprecise. To provide exact control of the laser fiber and precise delivery of laser energy, a new guide was devised. It conducts the quartz fiber through the sheath and along the lens of an optical urethrotome. The tip of the quartz fiber contacts the tissue at an angle of 20 degree(s). KTP/532 laser energy is used to perform internal urethrotomy for urethral stricture, transurethral incision of postoperative contracture of the vesical neck, and transurethral incision of the small prostate under constant visual control. Recently, a straight version of this guide, called probe director, was devised to conduct the newly marketed lateral firing laser probes. This probe director allows precise control of such a probe within the prostatic urethral lumen and excellent maneuverability of the probe during transurethral laser prostatectomy.

  8. Silicon knife-edge taper waveguide for ultralow-loss spot-size converter fabricated by photolithography

    NASA Astrophysics Data System (ADS)

    Takei, R.; Suzuki, M.; Omoda, E.; Manako, S.; Kamei, T.; Mori, M.; Sakakibara, Y.

    2013-03-01

    For ultralow-loss and polarization-insensitive spot-size converters (SSCs) on a silicon platform, we propose and demonstrate a silicon knife-edge taper waveguide with a gradual decrease in height as well as width toward the taper end. The taper was fabricated using a double-patterning method involving i-line stepper photolithography and angled sidewall dry-etching. The SSC, with the knife-edge taper covered with a polymer secondary core, exhibited mode conversion losses of 0.35 and 0.21 dB for transverse electric-like and transverse magnetic-like modes, respectively.

  9. The use of a Leksell-BRW adapter for linac radiosurgery as an adjunct to Gamma Knife treatment

    NASA Astrophysics Data System (ADS)

    Ekstrand, Kenneth E.; Hinson, William H.; Bourland, J. Daniel; de Guzman, Allan F.; Stieber, Volker W.; Tatter, Steven B.; Ellis, Thomas L.

    2003-12-01

    We have investigated the use of an adapter that permits the use of a Leksell coordinate frame with a linear accelerator stereotactic radiosurgery system based on the Brown-Robert-Wells (BRW) design. This device is useful when lesions that are planned for treatment on a Leksell Gamma Knife system are found to be inaccessible to the Gamma Knife. We have found that with this device objects within a head phantom can be targeted by the linear accelerator within an accuracy of approximately 1 mm.

  10. Dual daughter strand incision is processive and increases the efficiency of DNA mismatch repair.

    PubMed

    Hermans, Nicolaas; Laffeber, Charlie; Cristovão, Michele; Artola-Borán, Mariela; Mardenborough, Yannicka; Ikpa, Pauline; Jaddoe, Aruna; Winterwerp, Herrie H K; Wyman, Claire; Jiricny, Josef; Kanaar, Roland; Friedhoff, Peter; Lebbink, Joyce H G

    2016-08-19

    DNA mismatch repair (MMR) is an evolutionarily-conserved process responsible for the repair of replication errors. In Escherichia coli, MMR is initiated by MutS and MutL, which activate MutH to incise transiently-hemimethylated GATC sites. MMR efficiency depends on the distribution of these GATC sites. To understand which molecular events determine repair efficiency, we quantitatively studied the effect of strand incision on unwinding and excision activity. The distance between mismatch and GATC site did not influence the strand incision rate, and an increase in the number of sites enhanced incision only to a minor extent. Two GATC sites were incised by the same activated MMR complex in a processive manner, with MutS, the closed form of MutL and MutH displaying different roles. Unwinding and strand excision were more efficient on a substrate with two nicks flanking the mismatch, as compared to substrates containing a single nick or two nicks on the same side of the mismatch. Introduction of multiple nicks by the human MutLα endonuclease also contributed to increased repair efficiency. Our data support a general model of prokaryotic and eukaryotic MMR in which, despite mechanistic differences, mismatch-activated complexes facilitate efficient repair by creating multiple daughter strand nicks. PMID:27174933

  11. Force modeling for incisions into various tissues with MRF haptic master

    NASA Astrophysics Data System (ADS)

    Kim, Pyunghwa; Kim, Soomin; Park, Young-Dai; Choi, Seung-Bok

    2016-03-01

    This study proposes a new model to predict the reaction force that occurs in incisions during robot-assisted minimally invasive surgery. The reaction force is fed back to the manipulator by a magneto-rheological fluid (MRF) haptic master, which is featured by a bi-directional clutch actuator. The reaction force feedback provides similar sensations to laparotomy that cannot be provided by a conventional master for surgery. This advantage shortens the training period for robot-assisted minimally invasive surgery and can improve the accuracy of operations. The reaction force modeling of incisions can be utilized in a surgical simulator that provides a virtual reaction force. In this work, in order to model the reaction force during incisions, the energy aspect of the incision process is adopted and analyzed. Each mode of the incision process is classified by the tendency of the energy change, and modeled for realistic real-time application. The reaction force model uses actual reaction force information with three types of actual tissues: hard tissue, medium tissue, and soft tissue. This modeled force is realized by the MRF haptic master through an algorithm based on the position and velocity of a scalpel using two different control methods: an open-loop algorithm and a closed-loop algorithm. The reaction forces obtained from the proposed model are compared with a desired force in time domain.

  12. Lateral cutaneous femoral nerve blockade-limited skin incision coverage in hip arthroplasty.

    PubMed

    Davies, A; Crossley, Ap; Harper, Mw; O'Loughlin, Ej

    2014-09-01

    This paper seeks to assess the potential use of blocking the lateral cutaneous femoral nerve (LCN) for patients undergoing hip surgery. In this study, ultrasound guidance was used to specifically block the LCN using a small volume of local anaesthetic in 20 healthy volunteer anaesthetists. An orthopaedic surgeon then drew lines on the volunteers reflecting three common cutaneous incision lines (anterolateral, lateral, and posterior approach) for hip arthroplasty using an ultraviolet reflecting pen invisible in normal lighting. The relationship between the anaesthesia produced by this block and the marked incision lines was then assessed. More than half (32 of 60) of the drawn incision lines fell completely outside of the anaesthesia produced by the LCN block. Of the remaining incision lines drawn, most were less than half covered by LCN blockade with only three lines more than 50% covered and none more than 75% covered. The skin anaesthesia produced by LCN blockade was usually anterior and inferior to the surgical lines marked. This significant lack of overlap between common hip arthroplasty incision lines and the anaesthesia produced by blockade of the lateral cutaneous femoral nerve draws into question the utility of this block for hip surgery. PMID:25233177

  13. Dielectric relaxations in aliphatic polyesters

    NASA Astrophysics Data System (ADS)

    Sen, Sudeepto

    2001-07-01

    The dielectric technique was used to study the relaxation processes of five linear aliphatic polyesters. The polyesters studied were poly (ethylene succinate/adipate) or PESA, poly (trimethylene succinate/adipate) or PTSA, poly (butylene succinate/adipate) or PBSA, poly (ethylene succinate) or PES, and poly (ethylene adipate) or PEA. Three of the polyesters were copolymers (PESA, PTSA, and PBSA), and the remaining two (PES and PEA) were homopolymers. Two of the five were amorphous (PESA and PTSA), and the remaining three (PBSA, PES, and PEA) were semicrystalline. All the five polyesters were synthesized in the laboratory using a poly-condensation reaction between a series of aliphatic diols and diesters. The succinic and adipic groups in the copolymers are in equimolar amounts. The polymers were characterized by differential scanning calorimetry and density measurements. Elemental analysis done on the polymers confirmed that their compositions matched theoretical estimates. The relaxation processes were studied dielectrically using an IMASS time domain dielectric spectrometer (TDS) and an HP 4284A LCR meter. Together they allowed a frequency range from 0.001 Hz to 1 MHz. Typically in the subglass region, good data were obtained between 0.01 Hz and 100 kHz. In the glass transition region, good data were occasionally available over the entire range. Two relaxation processes were detected in the subglass temperature region for all the polymers, and in the case of the copolymers PTSA and PBSA, they were also well resolved. Both the processes showed Arrhenius behavior with modest activation energies characteristic of subglass processes in general. They also progressively merged with increasing temperature, which implies a lower activation energy for the faster process which is consistent with the current understanding of relaxation phenomena. The glass transition region of all the polymers also showed a merging of the dominant alpha relaxation with the subglass

  14. Steady incision of Grand Canyon at the million year timeframe: a case for mantle-driven differential uplift

    USGS Publications Warehouse

    Crow, Ryan S; Karl Karlstrom; Laura Crossey; Richard Young; Michael Ort; Yemane Asmerom; Victor Polyak; Andrew Darling

    2014-01-01

    The Grand Canyon region provides an excellent laboratory to examine the interplay between river incision, magmatism, and the geomorphic and tectonic processes that shape landscapes. Here we apply U-series, Ar–Ar, and cosmogenic burial dating of river terraces to examine spatial variations in incision rates along the 445 km length of the Colorado River through Grand Canyon. We also analyze strath terrace sequences that extend to heights of several hundred meters above the river, and integrate these with speleothem constrained maximum incision rates in several reaches to examine any temporal incision variations at the million-year time frame. This new high-resolution geochronology shows temporally steady long-term incision in any given reach of Grand Canyon but significant variations along its length from 160 m/Ma in the east to 101 m/Ma in the west. Spatial and temporal patterns of incision, and the long timescale of steady incision rule out models where geomorphic controls such as climate oscillations, bedrock strength, sediment load effects, or isostatic response to differential denudation are the first order drivers of canyon incision. The incision pattern is best explained by a model of Neogene and ongoing epeirogenic uplift due to an eastward propagating zone of increased upper mantle buoyancy that we infer from propagation of Neogene basaltic volcanism and a strong lateral gradient in modern upper mantle seismic structure.

  15. A signature of transience in bedrock river incision rates over timescales of 10(4)-10(7) years.

    PubMed

    Finnegan, Noah J; Schumer, Rina; Finnegan, Seth

    2014-01-16

    Measured rates of river incision into bedrock are commonly interpreted as proxies for rates of rock uplift (see refs 1 and 2, for example) and indices of the strength of climatic forcing of erosion over time (see refs 3 and 4, for example). This approach implicitly assumes that river incision rates are in equilibrium with external forcings over a wide range of timescales. Here we directly test this assumption by examining the temporal scaling of bedrock river incision from 155 independent measurements of river incision compiled from 14 sites. Of these sites, 11 exhibit a negative power-law dependence of bedrock river incision rate on measurement interval, a relationship that is apparent over timescales of 10(4)-10(7) years and is independent of tectonic and geomorphic setting. Thus, like rates of sediment accumulation, rates of river incision into bedrock exhibit non-steady-state behaviour even over very long measurement intervals. Non-steady-state behaviour can be explained by episodic hiatuses in river incision triggered by alluvial deposition, if such hiatuses have a heavy-tailed length distribution. Regardless of its cause, the dependence of incision rate on measurement interval complicates efforts to infer tectonic or climatic forcing from changes in rates of river incision over time or from comparison of rates computed over different timescales. PMID:24429636

  16. Comparison of the effects of 23-gauge and 25-gauge microincision vitrectomy blade designs on incision architecture

    PubMed Central

    Inoue, Makoto; Abulon, Dina Joy K; Hirakata, Akito

    2014-01-01

    Purpose To compare the effects of different 23- and 25-gauge microincision vitrectomy trocar cannula entry systems on incision architecture. Methods We tested one ridged microvitreoretinal (MVR), one non-ridged MVR, one pointed beveled, and one round-tipped beveled blade (n=10 per blade design per incision type). Each blade’s straight and oblique incision architecture was assessed in a silicone disc simulating the sclera. Wound leakage under pressure and endoscopic observations were conducted on sclerotomy sites of isolated porcine eyes (n=4 per blade design) after simulated vitrectomy. Results Differences in blade design created distinct incision architecture. Incisions were linear with the ridged MVR blade, flattened “M-shaped” with the non-ridged MVR blade, asymmetrical chevron-shaped with the pointed beveled blade, and curved with the round-tipped beveled blade. With the exception of oblique entry incision thickness, both MVR blade designs created thinner incisions than the beveled blades at entry and exit sites. Only the ridged MVR blade created incisions with no leakage. Vitreous incarceration was observed with all trocar cannula systems. Conclusion Wound closure in porcine eyes was similar with all blades despite differences in incision architecture. Wound leakage occurred at low to moderate infusion pressures with most blades; no wound leakage was observed with ridged MVR blades. PMID:25429201

  17. Scar due to skin incision for screw fixation through the transbuccal approach after sagittal split ramus osteotomy.

    PubMed

    Muto, Toshitaka

    2012-05-01

    Most rigid fixation techniques after sagittal split ramus osteotomies of the mandible involve the transbuccal approach. A skin incision in the cheek carries with it possible undesirable sequelae, such as noticeable scarring. The aim of this study was to investigate whether there is scarring in the face after this technique. For screw insertion, a 5-mm stab incision was performed on 40 Japanese patients (20 men and 20 women) with class III occlusion. After surgery, gross examination (via the naked eyes) of the skin incision was performed monthly for 1 year by the same oral surgeon. In all cases, the skin incision had disappeared by 1 year after the surgery. PMID:22627425

  18. Steady incision of Grand Canyon at the million year timeframe: A case for mantle-driven differential uplift

    NASA Astrophysics Data System (ADS)

    Crow, Ryan; Karlstrom, Karl; Darling, Andrew; Crossey, Laura; Polyak, Victor; Granger, Darryl; Asmerom, Yemane; Schmandt, Brandon

    2014-07-01

    The Grand Canyon region provides an excellent laboratory to examine the interplay between river incision, magmatism, and the geomorphic and tectonic processes that shape landscapes. Here we apply U-series, Ar-Ar, and cosmogenic burial dating of river terraces to examine spatial variations in incision rates along the 445 km length of the Colorado River through Grand Canyon. We also analyze strath terrace sequences that extend to heights of several hundred meters above the river, and integrate these with speleothem constrained maximum incision rates in several reaches to examine any temporal incision variations at the million-year time frame. This new high-resolution geochronology shows temporally steady long-term incision in any given reach of Grand Canyon but significant variations along its length from 160 m/Ma in the east to 101 m/Ma in the west. Spatial and temporal patterns of incision, and the long timescale of steady incision rule out models where geomorphic controls such as climate oscillations, bedrock strength, sediment load effects, or isostatic response to differential denudation are the first order drivers of canyon incision. The incision pattern is best explained by a model of Neogene and ongoing epeirogenic uplift due to an eastward propagating zone of increased upper mantle buoyancy that we infer from propagation of Neogene basaltic volcanism and a strong lateral gradient in modern upper mantle seismic structure.

  19. Equivalent Relaxations of Optimal Power Flow

    SciTech Connect

    Bose, S; Low, SH; Teeraratkul, T; Hassibi, B

    2015-03-01

    Several convex relaxations of the optimal power flow (OPF) problem have recently been developed using both bus injection models and branch flow models. In this paper, we prove relations among three convex relaxations: a semidefinite relaxation that computes a full matrix, a chordal relaxation based on a chordal extension of the network graph, and a second-order cone relaxation that computes the smallest partial matrix. We prove a bijection between the feasible sets of the OPF in the bus injection model and the branch flow model, establishing the equivalence of these two models and their second-order cone relaxations. Our results imply that, for radial networks, all these relaxations are equivalent and one should always solve the second-order cone relaxation. For mesh networks, the semidefinite relaxation and the chordal relaxation are equally tight and both are strictly tighter than the second-order cone relaxation. Therefore, for mesh networks, one should either solve the chordal relaxation or the SOCP relaxation, trading off tightness and the required computational effort. Simulations are used to illustrate these results.

  20. The laparotomy incision: a technique to facilitate capsulorhexis in microincision cataract surgery.

    PubMed

    O'Connor, Jeremy C; O'Connell, Eamon D; Sciscio, Andrea; Mulhern, Mark G

    2008-01-01

    Microincision cataract surgery is a new technique in the development of cataract surgery and is not without difficulties. Creation of the continuous curvilinear capsulorhexis as performed in conventional coaxial phacoemulsification surgery does not apply as readily. The authors describe a method for initiating the continuous curvilinear capsulorhexis (the laparotomy incision) using only an inexpensive 25-gauge bent needle cystototome. The technique involves a long linear incision in the anterior capsule down the belly of the lens as a means of initiating the capsulorhexis. Advantages of the technique include the creation of a large capsular flap, which allows easier completion of the continuous curvilinear capsulorhexis through a smaller range of movement, avoiding "oar locking" in the small incision and creation of striae in the cornea. It also allows better maintenance of anterior chamber depth, minimizing risk of radial tears. PMID:19065989

  1. Rapid late Pleistocene incision of Atlantic passive-margin river gorges.

    PubMed

    Reusser, Luke J; Bierman, Paul R; Pavich, Milan J; Zen, E-an; Larsen, Jennifer; Finkel, Robert

    2004-07-23

    The direct and secondary effects of rapidly changing climate caused large rivers draining the Atlantic passive margin to incise quickly into bedrock beginning about 35,000 years ago. Measured in samples from bedrock fluvial terraces, 10-beryllium shows that both the Susquehanna and Potomac Rivers incised 10- to 20-meter-deep gorges along steep, convex lower reaches during the last glacial cycle. This short-lived pulse of unusually rapid down-cutting ended by 13,000 to 14,000 years ago. The timing and rate of downcutting are similar on the glaciated Susquehanna and unglaciated Potomac Rivers, indicating that regional changes, not simply glacial meltwater, initiated incision. PMID:15273389

  2. Endoscopy-assisted resection of a submandibular gland mass via a thyroidectomy incision.

    PubMed

    Kim, Jin Pyeong; Park, Jung Je; Park, Hyun Woo; Woo, Seung Hoon

    2015-09-01

    Submandibular gland excision is traditionally performed via the transcervical approach. In an effort to avoid or reduce visible scarring and nerve injury, diverse innovative surgical trials have been conducted. We report the case of a submandibular gland mass that was endoscopically resected through a thyroidectomy incision. The patient was a 56-year-old woman with a long-standing right-sided submandibular gland mass and a smaller thyroid gland mass that was recently discovered on a routine checkup. The thyroid mass was managed with a total thyroidectomy. The submandibular mass was resected with endoscopic assistance through the thyroidectomy incision with an ultrasonic scalpel. The resection was successful, and the patient experienced no acute complications such as neural injury, hematoma, or seroma formation. Upon healing of the thyroidectomy scar, the cosmetic result was excellent. We conclude that endoscopic resection of a submandibular gland mass through a thyroidectomy incision is a feasible option that results in excellent surgical and cosmetic outcomes. PMID:26401679

  3. Triple, double- and single-incision laparoscopic cholecystectomy: a prospective study

    PubMed Central

    Sabuncuoglu, Mehmet Zafer; Benzin, Mehmet Fatih; Cakir, Tugrul; Sozen, Isa; Sabuncuoglu, Aylin

    2014-01-01

    Purpose: Advances in laparoscopic techniques have enabled complicated intra-abdominal surgical procedures to be made with less trauma and a better cosmetic appearance. The techniques have been developed by decreasing the number of incisions in conventional laparoscopic procedures in order to increase patient satisfaction. The aim of this study was to compare the results of cholecystectomies made with 3, 2 or a single incision. Method: A total of 95 cholecystectomy patients from Elbistan State Hospital and Suleyman Demirel University Hospital between 2011 and 2013 were prospectively evaluated. The patients were separated into 3 groups as triple incision laparoscopic cholecystectomy (TILC), double incision laparoscopic cholecystectomy (DILC) and single incision laparoscopic cholecystectomy (SILC). Patients were evaluated in respect of demographic characteristics, operation time, success rate, analgesia requirement, length of hospital stay and patient satisfaction. Results: Successful procedures were completed in 40 TILC, 40 DILC and 15 SILC cases. Transfer to open cholecystectomy was not required in any case. The mean duration of operation was 71 mins (range, 55-120 mins) for SILC cases, 45 mins (range, 32-125 mins) for DILC cases and 42 mins (range, 29-96 mins) for TILC cases. The mean time for the SILC cases was statistically significantly longer than the other two groups (p < 0.000). Conclusions: At a comparable level with DILC and TILC, single incision laparosccopic cholecystectomy is a method which can be used without incurring any extra costs or requiring additional instrumentation or training and which has good cosmetic results and a low requirement for analgesia. PMID:25419372

  4. Sequence stratigraphic and tectonic controls on Shannon incised-valley distribution, Hartzog Draw, Wyoming

    SciTech Connect

    Sullivan, M.D.; Van Wagoner, J.C.; Jennette, D.C.

    1996-12-31

    The Upper Cretaceous Shannon Sandstone in the Powder River Basin, Wyoming is interpreted as stacked tidal bars infilling northwest-southeast trending incised valleys. The Shannon Sandstone can be subdivided into 3 sequences: Copenhagen Blue, Crimson Red, and Canary Yellow. The Copenhagen Blue sequence boundary is a regional unconformity at the base of the Shannon Sandstone marked by distal tidal-bar deposits resting on offshore mudstones of the Cody. The overlying Crimson Red sequence is the main reservoir interval at Hartzog Draw and is composed of proximal tidal-bar deposits. The highly erosional Canary Yellow sequence boundary forms the trap at Hartzog Draw by juxtaposing the reservoir sandstones of the Crimson Red sequence with the overlying offshore mudstones of the Canary Yellow sequence. The Shannon Sandstone is therefore an erosional remnant of originally more extensive tide-dominated deltas deposited within northwest-southeast trending incised valleys. The orientation and distribution of the Shannon incised valleys is the result of the interplay between tectonics and eustacy. During lowstand incised valley development the orientation of fluvial systems incising the shelf was strongly controlled by pre-existing northwest-southeast trending structural elements in the basin. During the subsequent sea-level rise the shoreline backstepped in a landward direction. The shoreline also gradually rotated from an east-west orientation during the lowstand to a north-south orientation during the highstand systems tract. Ultimately the highstand shorelines were located over 160 kms landward of the lowstand shorelines and oriented subparallel to the lowstand incised valleys.

  5. Sequence stratigraphic and tectonic controls on Shannon incised-valley distribution, Hartzog Draw, Wyoming

    SciTech Connect

    Sullivan, M.D.; Van Wagoner, J.C.; Jennette, D.C. )

    1996-01-01

    The Upper Cretaceous Shannon Sandstone in the Powder River Basin, Wyoming is interpreted as stacked tidal bars infilling northwest-southeast trending incised valleys. The Shannon Sandstone can be subdivided into 3 sequences: Copenhagen Blue, Crimson Red, and Canary Yellow. The Copenhagen Blue sequence boundary is a regional unconformity at the base of the Shannon Sandstone marked by distal tidal-bar deposits resting on offshore mudstones of the Cody. The overlying Crimson Red sequence is the main reservoir interval at Hartzog Draw and is composed of proximal tidal-bar deposits. The highly erosional Canary Yellow sequence boundary forms the trap at Hartzog Draw by juxtaposing the reservoir sandstones of the Crimson Red sequence with the overlying offshore mudstones of the Canary Yellow sequence. The Shannon Sandstone is therefore an erosional remnant of originally more extensive tide-dominated deltas deposited within northwest-southeast trending incised valleys. The orientation and distribution of the Shannon incised valleys is the result of the interplay between tectonics and eustacy. During lowstand incised valley development the orientation of fluvial systems incising the shelf was strongly controlled by pre-existing northwest-southeast trending structural elements in the basin. During the subsequent sea-level rise the shoreline backstepped in a landward direction. The shoreline also gradually rotated from an east-west orientation during the lowstand to a north-south orientation during the highstand systems tract. Ultimately the highstand shorelines were located over 160 kms landward of the lowstand shorelines and oriented subparallel to the lowstand incised valleys.

  6. Comparison of surgically induced astigmatism between horizontal and X-pattern sutures in the scleral tunnel incisions for manual small incision cataract surgery

    PubMed Central

    Eslami, Yadollah; Mirmohammadsadeghi, Arash

    2015-01-01

    Background: Two types of popular scleral tunnel sutures in the manual small incision cataract surgery (MSICS) are horizontal and X-pattern sutures. Surgically induced corneal astigmatism (SIA) is a useful indicator of the suturing effect. Aims: To compare SIA between horizontal and X-pattern sutures in the scleral tunnel incisions for MSICS. Design: Prospective, nonrandomized comparative trial. Materials and Methods: After superior scleral tunnel incision and capsulorhexis, the nucleus was prolapsed into the anterior chamber and delivered. The wound was sutured with either horizontal or X-pattern suture. The simulated keratometry values were derived from the corneal topography preoperatively and 1.5 and 3 months postoperatively. Statistical Analysis: The SIA was calculated by Cartesian coordinates based analysis. Results: Sixty-four patients (32 patients in each group) were included in the study. In the horizontal suture group, the SIA centroid values at 1.5 and 3 months after the surgery were 0.87 × 1° and 1.11 × 180°, respectively, showing induction of against-the-rule astigmatism. In the X-pattern suture group, the SIA centroid values at 1.5 and 3 months after the surgery were 0.61 × 97° and 0.66 × 92°, respectively, showing induction of mild with-the-rule astigmatism. The difference between the amount of SIA at 1.5 and 3 months after surgery was small. Conclusion: In the MSICS, the X-pattern sutures were preferred to the horizontal sutures in the patients without significant preoperative steepening in line with the central meridian of the incision. In the cases with significant preoperative steepening, sutureless surgery or horizontal sutures were preferred. Corneal astigmatism in the patients undergoing MSICS was stable at 1.5 months after the surgery. PMID:26458479

  7. Computation of the Knife-Edge Cusp of a Rising Bubble in a Viscoelastic Fluid

    NASA Astrophysics Data System (ADS)

    You, Ruobo; Haj-Hariri, Hossein

    2006-11-01

    We consider the buoyant rise of an originally-spherical bubble through a viscoelastic fluid. Experiments have demonstrated that the sharp trailing edge could develop a three dimensional cusp of ``knife-like'' shape under certain conditions (high capillary number, large drop size). In order to understand the complex physics of this phenomenon, we have conducted a linear, three-dimensional temporal stability analysis of a computationally-obtained axisymmetric cusped bubble. The in-house time-accurate code is control-volume based and uses a body-fitted grid. Flux-difference splitting is employed to handle large Deborah numbers. Artificial compressibility is used for time marching. The resulting eigenanalysis shows the only linearly-unstable mode to be the one with azimuthal wavenumber of 2. The eigenvalue is real and the nature of instability is an exchange of stability. Thus an axisymmetric cusp can indeed develop into a knife-like shape. An investigation of the energy production and dissipation for the disturbances shows that the normal pressure gradient of the base-state along the free surface plays an important role in the evolution of the instability.

  8. Successful CyberKnife Irradiation of 1000 cc Hemicranial Meningioma: 6-year Follow-up

    PubMed Central

    Golanov, Andrey V.; Antipina, Natalia; Gorlachev, Gennady

    2015-01-01

    Meningiomas are common benign tumors with accepted treatment approaches and usually don't challenge healthcare specialists. We present a case of a huge unresectable hemicranial meningioma, which was successfully treated with hypofractionated irradiation. A male patient, sixty-two years of age, suffered for over 12 years from headaches, facial deformity, right eye displacement, right eye movement restriction, right-sided ptosis, and facial hypoesthesia. MRI and CT studies revealed an extended hemicranial meningioma. Prior to irradiation, the patient underwent four operations. Eventually, the tumor was irradiated with the CyberKnife in August 2009. Tumor volume composed 1085 cc. The mean dose of 35.3 Gy was delivered in 7 fractions (31.5 Gy at 72% isodose line comprising 95% of tumor volume). The patient was followed during six years and experienced only mild (Grade 1-2 CTCAE) acute skin and mucosa reactions. During the follow-up period, we observed target volume shrinkage for 17% (for 26% after excluding hyperostosis) and regression of intracranial hypertension signs. Due to the extreme volume and complex shape of the tumor, spreading along the surface of the hemisphere as well as an optic nerve involvement, the case presented would not be generally considered suitable for irradiation, especially for hypofractionation. We regard this clinical situation not as a treatment recommendation, but as a demonstration of the underestimated possibilities of hypofractionation regimen and CyberKnife system, both of which are limited with our habit of conventional treatments. PMID:26719827

  9. Initial Experience with the Extracorporeal HIFU Knife with 49 Patients: Japanese Experience

    NASA Astrophysics Data System (ADS)

    Ganaha, F.; Okuno, T.; Lee, C. O.; Shimizu, T.; Osako, K.; Oka, S.; Lee, K. H.; Chen, W. Z.; Zhu, H.; Park, S. H.; Qi, Z.; Shi, D.; Song, H. S.

    2005-03-01

    Forty nine patients with 63 tumours were treated with the Chongqing Haifu knife, as an adjunct to intra-arterial chemoinfusion. Treatment targets included breast (20 lesions), liver (16), bone (8), lymph-node (6), soft tissue (4), lung and pleura (4), pancreas (2), kidney (2) and adrenal gland (1). Follow-up contrast MRI was performed at 3 weeks to assess the effects of HIFU ablation. All cases completed the planned treatment. Of 25 lesions treated with the intention of complete tumour ablation, complete necrosis was obtained in 19 lesions (76%) including 4 secondary success cases. Among 32 lesions having partial and palliative treatment, tumour size was decreased in 6 lesions (21%), and good pain control was obtained in 6 out of 7 patients (86%). Skin injury was the most common complication after HIFU (16%), and was mostly a superficial dermal burn that did not necessitate any treatment. However, there was one patient with deep skin injury at an operation scar which resulted in skin perforation. Other adverse events included soft tissue swelling, prolonged fever, anorexia, persistent pain, shortness of the breath, sacroiliac joint fracture and prolonged diarrhoea. In our limited experience, superficial lesions (e.g. breast cancer, bone, soft tissue, lymph-node and pleural metastasis) appear to be good candidates for HIFU treatment. There appears to be a role for the HIFU knife in pain control for patients with bone metastasis and pancreatic cancer.

  10. Dose distribution transfer from CyberKnife to Varian treatment planning system

    NASA Astrophysics Data System (ADS)

    Osewski, W.; Ślosarek, K.; Karaszewska, B.

    2014-03-01

    The aim of this paper was to introduce one of the options of the locally developed DDcon.exe which gives the possibility to transfer the dose distribution from CyberKnife (Accuray) treatment planning system (CK TPS) to Varian treatment planning system (Eclipse TPS, Varian). DICOM format is known as a universal format for medical data. The dose distribution is stored as RTdose file in DICOM format, so there should be a possibility to transfer it between different treatment planning systems. Trying to transfer RTdose file from CK TPS to Eclipse TPS the error message occurs. That's because the RTdose file in CK TPS is connected with Structure_Set_Sequence against Eclipse TPS where it's connected with RT_Plan_Sequence. To make it transferable RTdose file from CK TPS have to be 'disconnected' from Structure_Set_Sequence and 'connected' with RT_Plan_Sequence. This is possible thanks DDcon software which creates new RTdose file by changing proper DICOM tags in original RTdose file. New homemade software gives us an opportunity to transfer dose distribution from CyberKnife TPS to TPS Eclipse. This method opens new possibilities to combine or compare different treatment techniques in Varian TPS.

  11. Effect of a cathodic knife edge on the PFMA-1 pinch performance

    NASA Astrophysics Data System (ADS)

    Mannucci, S.; Mostacci, D.; Rocchi, F.; Sumini, M.; Angeli, E.; Tartari, A.

    2009-05-01

    This paper presents some experimental results obtained with the plasma focus PFMA-1 operated at about 20.5 kV, corresponding to a total capacitor bank energy of about 70 kJ, with 4He as working gas and pressure ranging between 50 and 3000 Pa. The aim of the study is the assessment of the differences in pinch performance with and without the adoption of a cathodic knife edge with the role of improving the electrical breakdown and the formation of the initial plasma layer. The pinch performance is estimated with the introduction of a voltage quality factor, which is related to the overvoltage intensity during the pinch, and of a current dip factor, correlated with the sudden total current reduction. More than 1500 shots have been analyzed with a semiautomated numerical special procedure. It is found that the improvement in the pinch efficiency with the use of a cathodic knife edge in these experiments can be even higher than a factor of 2.

  12. Stereotactic gamma knife radiosurgery. Initial North American experience in 207 patients

    SciTech Connect

    Lunsford, L.D.; Flickinger, J.; Coffey, R.J. )

    1990-02-01

    The first North American gamma knife for stereotactic radiosurgery of brain tumors and arteriovenous malformations entered the therapeutic armamentarium at the University of Pittsburgh (Pa) on August 14, 1987. In this article, we report our initial testing and subsequent experience with this technique. In the first 16 months of operation, 207 patients were treated (113 had arteriovenous malformations, 78 had extra-axial skull base neoplasms, 9 had glial neoplasms, and 7 had metastatic tumors). The patients' lesions either were considered previously as inoperable or were residual lesions after attempted surgical resection, or the radiosurgery was performed after the patient declined surgical excision. Gamma radiosurgery was associated with no surgical mortality and no significant early morbidity, and the results were encouraging during the minimum follow-up period of 6 months. Compared with treatment by conventional intracranial surgery (craniotomy), both the average length of stay and hospital charges for radiosurgery were significantly lower. Our initial experience further suggests that stereotactic radiosurgery using the gamma knife is a therapeutically effective and economically sound alternative to microneurosurgical removal of selected intracranial tumors and vascular malformations.

  13. Gamma Knife Radiosurgery as a Therapeutic Strategy for Intracranial Sarcomatous Metastases

    SciTech Connect

    Flannery, Thomas; Kano, Hideyuki; Niranjan, Ajay M.Ch.; Monaco, Edward A.; Flickinger, John C.; Kofler, Julia; Lunsford, L. Dade; Kondziolka, Douglas

    2010-02-01

    Purpose: To determine the indication and outcomes for Gamma Knife stereotactic radiosurgery (GKSRS) in the care of patients with intracranial sarcomatous metastases. Methods and Materials: Data from 21 patients who underwent radiosurgery for 60 sarcomatous intracranial metastases (54 parenchymal and 6 dural-based) were studied. Nine patients had radiosurgery for solitary tumors and 12 for multiple tumors. The primary pathology was metastatic leiomyosarcoma (4 patients), osteosarcoma (3 patients), soft-tissue sarcoma (5 patients), chondrosarcoma (2 patients), alveolar soft part sarcoma (2 patients), and rhabdomyosarcoma, Ewing's sarcoma, liposarcoma, neurofibrosarcoma, and synovial sarcoma (1 patient each). Twenty patients received multimodality management for their primary tumor, and 1 patient had no evidence of systemic disease. The mean tumor volume was 6.2 cm{sup 3} (range, 0.07-40.9 cm{sup 3}), and a median margin dose of 16 Gy was administered. Three patients had progressive intracranial disease despite fractionated whole-brain radiotherapy before SRS. Results: A local tumor control rate of 88% was achieved (including patients receiving boost, up-front, and salvage SRS). New remote brain metastases developed in 7 patients (33%). The median survival after diagnosis of intracranial metastasis was 16 months, and the 1-year survival rate was 61%. Conclusions: Gamma Knife radiosurgery was a well-tolerated and initially effective therapy in the management of patients with sarcomatous intracranial metastases. However, many patients, including those who also received fractionated whole-brain radiotherapy, developed progressive new brain disease.

  14. Dosimetric characterization of CyberKnife radiosurgical photon beams using polymer gels

    SciTech Connect

    Pantelis, E.; Antypas, C.; Petrokokkinos, L.; Karaiskos, P.; Papagiannis, P.; Kozicki, M.; Georgiou, E.; Sakelliou, L.; Seimenis, I.

    2008-06-15

    Dose distributions registered in water equivalent, polymer gel dosimeters were used to measure the output factors and off-axis profiles of the radiosurgical photon beams employed for CyberKnife radiosurgery. Corresponding measurements were also performed using a shielded silicon diode commonly employed for CyberKnife commissioning, the PinPoint ion chamber, and Gafchromic EBT films, for reasons of comparison. Polymer gel results of this work for the output factors of the 5, 7.5, and 10 mm diameter beams are (0.702{+-}0.029), (0.872{+-}0.039), and (0.929{+-}0.041), respectively. Comparison of polymer gel and diode measurements shows that the latter overestimate output factors of the two small beams (5% for the 5 mm beam and 3% for the 7.5 mm beams). This is attributed to the nonwater equivalence of the high atomic number silicon material of the diode detector. On the other hand, the PinPoint chamber is found to underestimate output factors up to 10% for the 5 mm beam due to volume averaging effects. Polymer gel and EBT film output factor results are found in close agreement for all beam sizes, emphasizing the importance of water equivalence and fine detector sensitive volume for small field dosimetry. Relative off-axis profile results are in good agreement for all dosimeters used in this work, with noticeable differences observed only in the PinPoint estimate of the 80%-20% penumbra width, which is relatively overestimated.

  15. Stereotactic body radiotherapy using CyberKnife for locally advanced unresectable and metastatic pancreatic cancer

    PubMed Central

    Su, Ting-Shi; Liang, Ping; Lu, Huan-Zhen; Liang, Jian-Ning; Liu, Jian-Min; Zhou, Ying; Gao, Ying-Chuan; Tang, Min-Yang

    2015-01-01

    AIM: To evaluate the efficacy and toxicity of stereotactic body radiotherapy using CyberKnife for locally advanced unresectable and metastatic pancreatic cancer. METHODS: From June 2010 to May 2014, 25 patients with locally advanced unresectable and metastatic pancreatic cancer underwent stereotactic body radiotherapy. Nine patients presented with unresectable locally advanced disease and 16 had metastatic disease. Primary end-points of this study were overall survival, relief of abdominal pain, and toxicity. RESULTS: Fourteen patients were treated with a total dose of 30-36 Gy in three fractions and the remainder with 40-48 Gy in four fractions. Median follow-up was 11 mo (range: 2-25 mo). The median survival duration calculated from the time of stereotactic body radiotherapy for the entire group, the locally advanced group, and the metastatic group was 9.0 mo, 13.5 mo, and 8.5 mo, respectively. Overall survival was 37% and 18% at one and two years, respectively. Abdominal pain relief was achieved within 2 wk of completing radiotherapy in the patients who received successful palliation (13 of 20 patients had significant pain). Five patients (20%) had grade 1 nausea, and one (4%) had grade 2 nausea. No acute grade 3+ toxicity was seen. CONCLUSION: Stereotactic body radiotherapy using the CyberKnife system is a promising, noninvasive, palliative treatment with acceptable toxicity for locally advanced unresectable and metastatic pancreatic cancer. PMID:26185389

  16. Treatment of high numbers of brain metastases with Gamma Knife radiosurgery: a review.

    PubMed

    Hatiboglu, Mustafa Aziz; Tuzgen, Saffet; Akdur, Kerime; Chang, Eric L

    2016-04-01

    Effectiveness of stereotactic radiosurgery (SRS) has been shown in patients with one to four brain metastases. Work has been done to evaluate the role of SRS alone treatment without whole-brain radiation therapy in patients with more than four metastases. A recent multiinstitutional JLGK 0901 prospective study revealed the class-2 evidence that SRS without whole-brain radiation therapy is an effective treatment for patients up to 10 metastatic lesions. Several retrospective studies exist to show the efficacy and safety of SRS for patients with even more than 10 lesions. However, patient selection is very critical for SRS alone treatment. The PubMed database was searched using combinations of search terms and synonyms for multiple brain metastases, Gamma Knife and SRS published between January 1, 2005 and January 1, 2015 in order to address the effectiveness of Gamma Knife for patients with multiple brain metastases. Good performance status, controlled primary disease, total treated tumor volume of 15 cm(3) or less have been found to be significant predictors for survival among patients with two or more brain lesions. The data suggest that SRS can be used and whole brain radiation therapy can be withheld in selected patients with multiple lesions to avoid acute or chronic adverse effects, especially neurocognitive decline, without causing survival disadvantage. In this review, we assessed the evidence for SRS treatment of patients with multiple brain metastases. PMID:26811300

  17. Modification of a Standard Thoracoabdominal Incision to Preserve Collaterals to Adamkiewicz Artery.

    PubMed

    Takahara, Shingo; Kanda, Keisuke; Kawatsu, Satoshi; Yoshioka, Ichiro; Fujiwara, Hidenori; Adachi, Osamu; Akiyama, Masatoshi; Kumagai, Kiichiro; Kawamoto, Shunsuke; Ota, Hideki; Saiki, Yoshikatsu

    2016-09-01

    We report a case of a 35-year-old male who underwent thoracoabdominal aortic repair of a chronic dissecting aortic aneurysm, Crawford extent II. Preoperative computed tomography showed thrombosis of almost all intercostal arteries. Precise diagnostic assessment demonstrated the Adamkiewicz artery originating from the left lateral thoracic artery and subscapular artery, which would have been at risk after using a standard Stoney's incision, thus potentially causing paraplegia or paraparesis due to spinal cord ischemia. We modified the lateral thoracic incision anteriorly and successfully preserved the collateral arteries without impairing the spinal cord function. PMID:27549554

  18. Cenozoic incision history of the Little Colorado River and its role in carving Grand Canyon

    NASA Astrophysics Data System (ADS)

    Karlstrom, K. E.

    2015-12-01

    Multi-stage incision/denudation history for the southwestern Colorado Plateau involved: carving of 70-30 Ma Laramide paleotopography controlled by strike valleys at the base of retreating cliffs, 25-15 Ma incision of an East Kaibab paleovalley that cut to about half the modern depth of eastern Grand Canyon, and 5-6 Ma integration of the Colorado River (CR) through Grand Canyon. A synthesis of Little Colorado River (LCR) incision history informs aspects of each episode. Refined evidence for the first two episodes is from new thermochronology modeling that shows post-Laramide NE cliff retreat and a 35-25 Ma LCR paleovalley that flowed NW across the Kaibab uplift. Next was 16-14 Ma playa/ marsh deposition of Lower Bidahochi Formation, 13-8 Ma non-deposition, and 6-8 fluvial upper Bidahochi Formation with base level defined by Hopi Buttes maars. Little denudation in the LCR valley from 16 to 6 Ma is documented by similar elevations of 16 and 6 Ma paleo baselevels. The third pulse of regional incision/denudation was associated with integration of the CR across the Vermillion Cliffs after 5-6 Ma. Earliest integration reoccupied the East Kaibab paleocanyon, inferred from thermochronology to have been at ~1500-1700 m elevation at 15 Ma. Topographically inverted dated basalt mesas in the LCR headwater region show steady incision of 43 m/Ma since 6 Ma. New 2 Ma sanidine ages for Crooked Ridge and Blue Point ash show ~100 m/Ma differential incision across the LCR knickpoint over the last ~ 2 Ma: ~400 m (~200 m/Ma) at the confluence, 400-500 m (200-250 m/Ma) at the projected confluence of Crooked Ridge and the LCR, 220 m (110 m/Ma) for topographically inverted basalt mesas in LCR tributaries in the central reaches, and 116-204 m (61-43 m/Ma) in the headwaters. Headwater uplift of the Rocky Mountains likely facilitated CR integration; post-2 Ma differential incision in the LCR may reflect a combination of regional mantle-driven epeirogenic uplift and additional mantle

  19. [Advance of femtosecond small incision lenticule extraction (SMILE) in clinic application].

    PubMed

    Liang, Gang; Zhang, Fengju

    2016-01-01

    Femtosecond small incision lenticule extraction (SMILE) had been performed in clinic more than 5 years in China. With the gradual development of the technology, SMILE has caused more and more attention because of the remarkable clinical effect, micro incision, minimally invasive and refractive stability. The reuse of the refractive lenticule (RL) from SMILE has recently become extensive focus, which brings potential method to corneal refractive surgery from subtraction to addition. This review has clarified the technology of SMILE on the aspects of corneal refractive correct, the clinical effect of reuse the materials (RL), the basis of related research and the possible improvement in the future. PMID:26899224

  20. Trap-Door Incision for Penetrating Thoracic Trauma: An Obsolete Approach?

    PubMed Central

    Fabregues Olea, Ana; Perez-Diaz, Dolores; Turégano Fuentes, Fernando

    2014-01-01

    Penetrating injuries to the subclavian vessels are uncommon and very severe lesions. They are difficult to expose and carry a high mortality. “Trap-door” incisions have lately been dismissed as too mutilating for the occasional victim of a penetrating thoracic trauma with massive bleeding difficult that is to expose. We present a case of severe bleeding from a stab wound in the left subclavicular area in a heavy-built patient where a “trap-door” incision proved inevitable to expose and repair the injury, and most probably saved his life. PMID:25165611

  1. Incision of the Yangtze River at the First Bend Determined by Three-Nuclide Burial Dating

    NASA Astrophysics Data System (ADS)

    McPhillips, D. F.; Hoke, G. D.; Rood, D. H.; Bierman, P. R.

    2015-12-01

    On the southeast margin of the Tibetan Plateau, the evolution of the Yangtze River and its major tributaries has become an important source of data for investigating geodynamics. In particular, the timing of river incision is frequently interpreted as a proxy for the timing of surface uplift in the absence of structural evidence. We investigate the timing of the incision of the gorge at the First Bend using cosmogenic nuclide burial dating of coarse, quartz sediments from caves. Sediments were deposited when the caves were near river level and subsequently abandoned as the river incised. To resolve burial ages >5 Ma, we measured the radionuclides 10Be and 26Al, and the stable nuclide 21Ne. Results from 4 caves show that 26Al and 10Be concentrations are an order of magnitude lower in abandoned cave samples than in a river-level cave sample where deposition is active (10Be: 1.3x104 and 3.4x105 at/g). In contrast, 26Al/10Be ratios in all caves are ≥6.2 and indistinguishable within error. 21Ne concentrations range from 2.1x106 to 7.8x106 at/g. The results are consistent with an old age for the abandoned cave deposits, such that most of the radionuclides initially present have decayed and the concentrations that we measure today are the result of millions of years of exposure to muons. We solve for burial ages, taking into account in situ muogenic production, and find that the majority of the gorge (1 km) was likely incised between ~12 and 9 Ma. The results also require that the rate of river incision declined after the gorge was cut below the lowest elevation cave at 9 Ma. Inverse modeling of published low-temperature thermochronology (Ouimet et al., 2010) supports our burial age results. River capture near the First Bend, which likely integrated the modern Yangtze, likely occurred prior to the mid-Miocene incision of the gorge. In view of the geographic position of the First Bend—just downslope from the southeast margin of the Plateau—it is difficult to explain

  2. Plasmon-mediated energy relaxation in graphene

    NASA Astrophysics Data System (ADS)

    Ferry, D. K.; Somphonsane, R.; Ramamoorthy, H.; Bird, J. P.

    2015-12-01

    Energy relaxation of hot carriers in graphene is studied at low temperatures, where the loss rate may differ significantly from that predicted for electron-phonon interactions. We show here that plasmons, important in the relaxation of energetic carriers in bulk semiconductors, can also provide a pathway for energy relaxation in transport experiments in graphene. We obtain a total loss rate to plasmons that results in energy relaxation times whose dependence on temperature and density closely matches that found experimentally.

  3. Plasmon-mediated energy relaxation in graphene

    SciTech Connect

    Ferry, D. K.; Somphonsane, R.; Ramamoorthy, H.; Bird, J. P.

    2015-12-28

    Energy relaxation of hot carriers in graphene is studied at low temperatures, where the loss rate may differ significantly from that predicted for electron-phonon interactions. We show here that plasmons, important in the relaxation of energetic carriers in bulk semiconductors, can also provide a pathway for energy relaxation in transport experiments in graphene. We obtain a total loss rate to plasmons that results in energy relaxation times whose dependence on temperature and density closely matches that found experimentally.

  4. Correlation and prediction uncertainties in the CyberKnife Synchrony respiratory tracking system

    SciTech Connect

    Pepin, Eric W.; Wu, Huanmei; Zhang, Yuenian; Lord, Bryce

    2011-07-15

    Purpose: The CyberKnife uses an online prediction model to improve radiation delivery when treating lung tumors. This study evaluates the prediction model used by the CyberKnife radiation therapy system in terms of treatment margins about the gross tumor volume (GTV). Methods: From the data log files produced by the CyberKnife synchrony model, the uncertainty in radiation delivery can be calculated. Modeler points indicate the tracked position of the tumor and Predictor points predict the position about 115 ms in the future. The discrepancy between Predictor points and their corresponding Modeler points was analyzed for 100 treatment model data sets from 23 de-identified lung patients. The treatment margins were determined in each anatomic direction to cover an arbitrary volume of the GTV, derived from the Modeler points, when the radiation is targeted at the Predictor points. Each treatment model had about 30 min of motion data, of which about 10 min constituted treatment time; only these 10 min were used in the analysis. The frequencies of margin sizes were analyzed and truncated Gaussian normal functions were fit to each direction's distribution. The standard deviation of each Gaussian distribution was then used to describe the necessary margin expansions in each signed dimension in order to achieve the desired coverage. In this study, 95% modeler point coverage was compared to 99% modeler coverage. Two other error sources were investigated: the correlation error and the targeting error. These were added to the prediction error to give an aggregate error for the CyberKnife during treatment of lung tumors. Results: Considering the magnitude of 2{sigma} from the mean of the Gaussian in each signed dimension, the margin expansions needed for 95% modeler point coverage were 1.2 mm in the lateral (LAT) direction and 1.7 mm in the anterior-posterior (AP) direction. For the superior-inferior (SI) direction, the fit was poor; but empirically, the expansions were 3.5 mm

  5. Viscoelastic Relaxation of Lunar Basins

    NASA Astrophysics Data System (ADS)

    Mohit, P. S.; Phillips, R. J.

    2004-12-01

    The large lunar impact basins provide a unique glimpse into early lunar history. Here we investigate the possibility that the relief of the oldest lunar basins (with the exception of South-Pole Aitken) has decayed through viscous relaxation. We identify nine ancient multi-ring basins with very low relief and low-amplitude Bouguer and free-air gravity anomalies. The characteristics of these basins are consistent with either 1) relaxation of topographic relief by ductile flow (e.g. Solomon et al., 1982) or 2) obliteration of basin topography during crater collapse immediately following impact. Both scenarios require that the basins formed early in lunar history, when the Moon was hot. The latter possibility appears to be unlikely due to the great topographic relief of South Pole-Aitken basin (SPA), the largest and oldest impact basin on the Moon (with the possible exception of the putative Procellarum basin; Wilhelms, 1987). On the other hand, the thin crust beneath SPA may not have allowed ductile flow in its lower portions, even for a hot Moon, implying that a thicker crust is required beneath other ancient basins for the hypothesis of viscous relaxation to be tenable. Using a semi-analytic, self-gravitating viscoelastic model, we investigate the conditions necessary to produce viscous relaxation of lunar basins. We model topographic relaxation for a crustal thickness of 30 km, using a dry diabase flow law for the crust and dry olivine for the mantle. We find that the minimum temperature at the base of the crust (Tb) permitting nearly complete relaxation of topography by ductile flow on a timescale < 108 yrs is 1400 K, corresponding to a heat flow of 55mW/m2, into the crust. Ductile flow in the lower crust becomes increasingly difficult as the crustal thickness decreases. The crust beneath SPA, thinned by the impact, is only 15-20 km thick and would require Tb ≥ 1550 K for relaxation to occur. The fact that SPA has maintained high-amplitude relief suggests that

  6. Kinetic activation-relaxation technique.

    PubMed

    Béland, Laurent Karim; Brommer, Peter; El-Mellouhi, Fedwa; Joly, Jean-François; Mousseau, Normand

    2011-10-01

    We present a detailed description of the kinetic activation-relaxation technique (k-ART), an off-lattice, self-learning kinetic Monte Carlo (KMC) algorithm with on-the-fly event search. Combining a topological classification for local environments and event generation with ART nouveau, an efficient unbiased sampling method for finding transition states, k-ART can be applied to complex materials with atoms in off-lattice positions or with elastic deformations that cannot be handled with standard KMC approaches. In addition to presenting the various elements of the algorithm, we demonstrate the general character of k-ART by applying the algorithm to three challenging systems: self-defect annihilation in c-Si (crystalline silicon), self-interstitial diffusion in Fe, and structural relaxation in a-Si (amorphous silicon). PMID:22181304

  7. Models of violently relaxed galaxies

    NASA Astrophysics Data System (ADS)

    Merritt, David; Tremaine, Scott; Johnstone, Doug

    1989-02-01

    The properties of spherical self-gravitating models derived from two distribution functions that incorporate, in a crude way, the physics of violent relaxation are investigated. The first distribution function is identical to the one discussed by Stiavelli and Bertin (1985) except for a change in the sign of the 'temperature', i.e., e exp(-aE) to e exp(+aE). It is shown that these 'negative temperature' models provide a much better description of the end-state of violent relaxation than 'positive temperature' models. The second distribution function is similar to the first except for a different dependence on angular momentum. Both distribution functions yield single-parameter families of models with surface density profiles very similar to the R exp 1/4 law. Furthermore, the central concentration of models in both families increases monotonically with the velocity anisotropy, as expected in systems that formed through cold collapse.

  8. Shear Relaxations of Confined Liquids.

    NASA Astrophysics Data System (ADS)

    Carson, George Amos, Jr.

    Ultrathin (<40 A) films of octamethylcyclotetrasiloxane (OMCTS), hexadecane, and dodecane were subjected to linear and non-linear oscillatory shear between flat plates. Shearing frequencies of 0.1 to 800 s^{-1} were applied at pressures from zero to 0.8 MPa using a surface rheometer only recently developed. In most cases the plates were atomically smooth mica surfaces; the role of surface interactions was examined by replacing these with alkyl chain monolayers. OMCTS and hexadecane were examined at a temperature about 5 Celsius degrees above their melting points and tended to solidify. Newtonian plateaus having enormous viscosities were observed at low shear rates. The onset of shear thinning implied relaxation times of about 0.1 s in the linear structure of the confined liquids. Large activation volumes (~80 nm ^3) suggested that shear involved large-scale collective motion. Dodecane was studied at a much higher temperature relative to its melting point and showed no signs of impending solidification though it exhibited well-defined regions of Newtonian response and power law shear thinning. When treated with molecular sieves before use, dodecane had relaxation times which were short (0.02 s) compared to hexadecane, but still exhibited large-scale collective motion. When treated with silica gel, an unexplained long -time relaxation (10 s) was seen in the Newtonian viscosity of dodecane. The relaxation time of the linear structure, 0.005 s was very small, and the storage modulus was unresolvable. The small activation volume (7nm^3) indicated a much lower level of collective motion. The activation volume remained small when dodecane was confined between tightly bound, low energy, alkyl monolayers. At low strains the storage and loss moduli became very large (>10^4 Pa), probably due to interactions with flaws in the monolayers. Dramatic signs of wall slip were observed at large strains even at low pressures.

  9. Dynamic Relaxation of Financial Indices

    NASA Astrophysics Data System (ADS)

    Shen, J.; Zheng, B.; Lin, H.; Qiu, T.

    The dynamic relaxation of the German DAX both before and after a large price-change is investigated. The dynamic behavior is characterized by a power law. At the minutely time scale, the exponent p governing the power-law behavior takes a same value before and after the large price change, while at the daily time scale, it is different. Numerical simulations of an interacting EZ herding model are performed for comparison.

  10. Shear relaxations of confined liquids

    SciTech Connect

    Carson, G.A. Jr.

    1992-01-01

    Ultrathin (<40 [angstrom]) films of octamethylcyclotetrasiloxane (OMCTS), hexadecane, and dodecane were subjected to linear and non-linear oscillatory shear between flat plates. Shearing frequencies of 0.1 to 800 s[sup [minus]1] were applied at pressures from zero to 0.8 MPa using a surface rheometer only recently developed. In most cases the plates were atomically smooth mica surfaces; the role of surface interactions was examined by replacing these with alkyl chain monolayers. OMCTS and hexadecane were examined at a temperature about 5 Celcius degrees above their melting points and tended to solidify. Newtonian plateaus having enormous viscosities were observed at low shear rates. The onset of shear thinning implied relaxation times of about 0.1 s in the linear structure of the confined liquids. Large activation volumes ([approximately]80 nm[sup 3]) suggested that shear involved large-scale collective motion. Dodecane was studied at a much higher temperature relative to its melting point and showed no signs of impending solidification though it exhibited well-defined regions of Newtonian response and power law shear thinning. When treated with molecular sieves before use, dodecane had relaxation times which were short (0.02 s) compared to hexadecane, but still exhibited large-scale collective motion. When treated with silica gel, an unexplained long-time relaxation (10 s) was seen in the Newtonian viscosity of dodecane. The relaxation time of the linear structure, 0.005 s was very small, and the storage modulus was unresolvable. The small activation volume (7 nm[sup 3]) indicated a much lower level of collective motion. The activation volume remained small when dodecane was confined between tightly bound, low energy, alkyl monolayers. At low strains the storage and loss moduli became very large (>10[sup 4] Pa), probably due to interactions with flaws in the monolayers. Dramatic signs of wall slip were observed at large strains even at low pressures.

  11. Relaxation: A Fourth "R" for Education.

    ERIC Educational Resources Information Center

    Frederick, A. B.

    Relaxation training helps the individual handle tension through concentrating upon efficient use of muscles. A program of progressive relaxation can be easily incorporated into elementary and secondary schools. Objectives of such a program include the following: (a) to learn to relax technically for purposes of complete rest (deep muscle…

  12. Comparative evaluation of fracture resistance of Ceramic Veneer with three different incisal design preparations - An In-vitro Study

    PubMed Central

    Jankar, Ajit S; Kale, Yogesh; Kangane, Suresh; Ambekar, Anand; Sinha, Manish; Chaware, Sachin

    2014-01-01

    Background: Ceramic veneer fracture has occurred mainly at the incisal edge of the veneer because of greater stress. This study compares and evaluates the fracture resistance ceramic veneers with three different incisal preparations. Materials & Methods: 15 human permanent maxillary central incisor extracted were selected which were divided into three groups of 5 each having a different Incial design Preparation. Group 1: No Incisal reduction with facio- incisal bevel, Group 2 : 1 mm incisal reduction with butt joint, Group 3 : 1 mm incisal reduction with 1 mm height of Palatal chamfer. It was found that Group III had greater fracture resistance as compared to Group I and Group II. Group I had least fracture resistance as compared to Group II and III. Group II had greater fracture resistance as compared to Group I but less than Group III. Results: Ceramic veneer with 1mm incisal reduction with 1mm height of palatal chamfer showed highest fracture resistance as compared to 1mm incisal reduction with butt joint and no incisal reduction with facial-incisal bevel, in order to achieve better esthetic and functional results. Conclusion: The palatal chamfer margin results in preservation of some peripheral enamel layer, which eliminates the micro leakage at the palatal margin-restoration interface and also effectively counteracting shear stress. This design provides a definite seat for cementation. How to cite the article: Jankar AS, Kale Y, Kangane S, Ambekar A, Sinha M, Chaware S. Comparative evaluation of fracture resistance of Ceramic Veneer with three different incisal design preparations - An In-vitro Study. J Int Oral Health 2014;6(1):48-54. PMID:24653603

  13. Arresting relaxation in Pickering Emulsions

    NASA Astrophysics Data System (ADS)

    Atherton, Tim; Burke, Chris

    2015-03-01

    Pickering emulsions consist of droplets of one fluid dispersed in a host fluid and stabilized by colloidal particles absorbed at the fluid-fluid interface. Everyday materials such as crude oil and food products like salad dressing are examples of these materials. Particles can stabilize non spherical droplet shapes in these emulsions through the following sequence: first, an isolated droplet is deformed, e.g. by an electric field, increasing the surface area above the equilibrium value; additional particles are then adsorbed to the interface reducing the surface tension. The droplet is then allowed to relax toward a sphere. If more particles were adsorbed than can be accommodated by the surface area of the spherical ground state, relaxation of the droplet is arrested at some non-spherical shape. Because the energetic cost of removing adsorbed colloids exceeds the interfacial driving force, these configurations can remain stable over long timescales. In this presentation, we present a computational study of the ordering present in anisotropic droplets produced through the mechanism of arrested relaxation and discuss the interplay between the geometry of the droplet, the dynamical process that produced it, and the structure of the defects observed.

  14. Spin relaxation in metallic ferromagnets

    NASA Astrophysics Data System (ADS)

    Berger, L.

    2011-02-01

    The Elliott theory of spin relaxation in metals and semiconductors is extended to metallic ferromagnets. Our treatment is based on the two-current model of Fert, Campbell, and Jaoul. The d→s electron-scattering process involved in spin relaxation is the inverse of the s→d process responsible for the anisotropic magnetoresistance (AMR). As a result, spin-relaxation rate 1/τsr and AMR Δρ are given by similar formulas, and are in a constant ratio if scattering is by solute atoms. Our treatment applies to nickel- and cobalt-based alloys which do not have spin-up 3d states at the Fermi level. This category includes many of the technologically important magnetic materials. And we show how to modify the theory to apply it to bcc iron-based alloys. We also treat the case of Permalloy Ni80Fe20 at finite temperature or in thin-film form, where several kinds of scatterers exist. Predicted values of 1/τsr and Δρ are plotted versus resistivity of the sample. These predictions are compared to values of 1/τsr and Δρ derived from ferromagnetic-resonance and AMR experiments in Permalloy.

  15. Flood magnitude frequency and lithologic control on bedrock river incision in post-orogenic terrain

    NASA Astrophysics Data System (ADS)

    Jansen, John D.

    2006-12-01

    Mixed bedrock-alluvial rivers-bedrock channels lined with a discontinuous alluvial cover-are key agents in the shaping of mountain belt topography by bedrock fluvial incision. Whereas much research focuses upon the erosional dynamics of such rivers in the context of rapidly uplifting orogenic landscapes, the present study investigates river incision processes in a post-orogenic (cratonic) landscape undergoing extremely low rates of incision (< 5 m/Ma). River incision processes are examined as a function of substrate lithology and the magnitude and frequency of formative flows along Sandy Creek gorge, a mixed bedrock-alluvial stream in arid SE-central Australia. Incision is focused along a bedrock channel with a partial alluvial cover arranged into riffle-pool macrobedforms that reflect interactions between rock structure and large-flood hydraulics. Variations in channel width and gradient determine longitudinal trends in mean shear stress ( τb) and therefore also patterns of sediment transport and deposition. A steep and narrow, non-propagating knickzone (with 5% alluvial cover) coincides with a resistant quartzite unit that subdivides the gorge into three reaches according to different rock erodibility and channel morphology. The three reaches also separate distinct erosional styles: bedrock plucking (i.e. detachment-limited erosion) prevails along the knickzone, whereas along the upper and lower gorge rock incision is dependent upon large formative floods exceeding critical erosion thresholds ( τc) for coarse boulder deposits that line 70% of the channel thalweg (i.e. transport-limited erosion). The mobility of coarse bed materials (up to 2 m diameter) during late Holocene palaeofloods of known magnitude and age is evaluated using step-backwater flow modelling in conjunction with two selective entrainment equations. A new approach for quantifying the formative flood magnitude in mixed bedrock-alluvial rivers is described here based on the mobility of a key

  16. Relation between Direct Observation of Relaxation and Self-Reported Mindfulness and Relaxation States

    ERIC Educational Resources Information Center

    Hites, Lacey S.; Lundervold, Duane A.

    2013-01-01

    Forty-four individuals, 18-47 (MN 21.8, SD 5.63) years of age, took part in a study examining the magnitude and direction of the relationship between self-report and direct observation measures of relaxation and mindfulness. The Behavioral Relaxation Scale (BRS), a valid direct observation measure of relaxation, was used to assess relaxed behavior…

  17. Effects of Progressive Relaxation versus Biofeedback-Assisted Relaxation with College Students.

    ERIC Educational Resources Information Center

    See, John D.; Czerlinsky, Thomas

    1990-01-01

    Examined use of biofeedback, relaxation training, or both in a college relaxation class with an enrollment of 33 students. Results indicated students receiving relaxation training plus biofeedback improved significantly more on psychological variables than did students receiving only relaxation training. (Author/ABL)

  18. Dynamics of Glass Relaxation at Room Temperature

    NASA Astrophysics Data System (ADS)

    Welch, Roger C.; Smith, John R.; Potuzak, Marcel; Guo, Xiaoju; Bowden, Bradley F.; Kiczenski, T. J.; Allan, Douglas C.; King, Ellyn A.; Ellison, Adam J.; Mauro, John C.

    2013-06-01

    The problem of glass relaxation under ambient conditions has intrigued scientists and the general public for centuries, most notably in the legend of flowing cathedral glass windows. Here we report quantitative measurement of glass relaxation at room temperature. We find that Corning® Gorilla® Glass shows measurable and reproducible relaxation at room temperature. Remarkably, this relaxation follows a stretched exponential decay rather than simple exponential relaxation, and the value of the stretching exponent (β=3/7) follows a theoretical prediction made by Phillips for homogeneous glasses.

  19. Time of relaxation in dusty plasma model

    NASA Astrophysics Data System (ADS)

    Timofeev, A. V.

    2015-11-01

    Dust particles in plasma may have different values of average kinetic energy for vertical and horizontal motion. The partial equilibrium of the subsystems and the relaxation processes leading to this asymmetry are under consideration. A method for the relaxation time estimation in nonideal dusty plasma is suggested. The characteristic relaxation times of vertical and horizontal motion of dust particles in gas discharge are estimated by analytical approach and by analysis of simulation results. These relaxation times for vertical and horizontal subsystems appear to be different. A single hierarchy of relaxation times is proposed.

  20. Properties of damage-dependent DNA incision by nucleotide excision repair in human cell-free extracts.

    PubMed Central

    Calsou, P; Salles, B

    1994-01-01

    Nucleotide excision repair (NER) is the primary mechanism for the removal of many lesions from DNA. This repair process can be broadly divided in two stages: first, incision at damaged sites and second, synthesis of new DNA to replace the oligonucleotide removed by excision. In order to dissect the repair mechanism, we have recently devised a method to analyze the incision reaction in vitro in the absence of repair synthesis (1). Damage-specific incisions take place in a repair reaction in which mammalian cell-free extracts are mixed with undamaged and damaged plasmids. Most of the incision events are accompanied by excision. Using this assay, we investigated here various parameters that specifically affect the level of damage-dependent incision activity by cell-free extracts in vitro. We have defined optimal conditions for the reaction and determined the kinetics of the incision with cell-free extracts from human cells. We present direct evidence that the incision step of NER is ATP-dependent. In addition, we observe that Mn2+ but no other divalent cation can substitute for Mg2+ in the incision reaction. Images PMID:7800483

  1. Efficacy of Single-Suture Incision Closures in Tagged Juvenile Chinook Salmon Exposed to Simulated Turbine Passage

    SciTech Connect

    Boyd, James W.; Deters, Katherine A.; Brown, Richard S.; Eppard, M. B.

    2011-09-01

    Reductions in the size of acoustic transmitters implanted in migrating juvenile salmonids have resulted in the use of a shorter incision-one that may warrant only a single suture for closure. However, it is not known whether a single suture will sufficiently hold the incision closed when fish are decompressed and when outward pressure is placed on the surgical site during turbine passage through hydroelectric dams. The objective of this study was to evaluate the effectiveness of single-suture incision closures on five response variables in juvenile Chinook salmon Oncorhynchus tshawytscha that were subjected to simulated turbine passage. An acoustic transmitter (0.43 g in air) and a passive integrated transponder tag (0.10 g in air) were implanted in each fish; the 6-mm incisions were closed with either one suture or two sutures. After exposure to simulated turbine passage, none of the fish exhibited expulsion of transmitters. In addition, the percentage of fish with suture tearing, incision tearing, or mortal injury did not differ between treatments. Expulsion of viscera through the incision was higher among fish that received one suture (12%) than among fish that received two sutures (1%). The higher incidence of visceral expulsion through single-suture incisions warrants concern. Consequently, for cases in which tagged juvenile salmonidsmay be exposed to turbine passage, we do not recommend the use of one suture to close 6-mm incisions associated with acoustic transmitter implantation.

  2. DISTURBANCE, STREAM INCISION, AND CHANNEL EVOLUTION: THE ROLES OF EXCESS TRANSPORT CAPACITY AND BOUNDARY MATERIALS IN CONTROLLING CHANNEL RESPONSE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Channel incision is part of denudation, drainage-network development, and landscape evolution. Large, anthropogenic disturbances, similar to large or catastrophic “natural” events, greatly compress time scales for incision and related processes by creating enormous imbalances between upstream sedime...

  3. Unusual fast secondary relaxation in metallic glass

    PubMed Central

    Wang, Q.; Zhang, S.T.; Yang, Y.; Dong, Y.D.; Liu, C.T.; Lu, J.

    2015-01-01

    The relaxation spectrum of glassy solids has long been used to probe their dynamic structural features and the fundamental deformation mechanisms. Structurally complicated glasses, such as molecular glasses, often exhibit multiple relaxation processes. By comparison, metallic glasses have a simple atomic structure with dense atomic packing, and their relaxation spectra were commonly found to be simpler than those of molecular glasses. Here we show the compelling evidence obtained across a wide range of temperatures and frequencies from a La-based metallic glass, which clearly shows two peaks of secondary relaxations (fast versus slow) in addition to the primary relaxation peak. The discovery of the unusual fast secondary relaxation unveils the complicated relaxation dynamics in metallic glasses and, more importantly, provides us the clues which help decode the structural features serving as the ‘trigger' of inelasticity on mechanical agitations. PMID:26204999

  4. Rehabilitation of an incised stream using plant materials: the dominance of geomorphic processes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Restoration of potentially species-rich stream ecosystems in physically unstable environments is challenging, and few attempts have been scientifically evaluated. A 2-km reach of an incised, sand-bed stream in northern Mississippi was treated with large wood structures and willow plantings to trigg...

  5. Outcomes of single-stage total arch replacement via clamshell incision

    PubMed Central

    2011-01-01

    Background Treatment of complex aortic pathologies involving the transverse arch with extensive involvement of the descending aorta remains a surgical challenge. Since clamshell incision provides superior exposure of the entire thoracic aorta, we evaluated the use of this technique for single-stage total arch replacement by arch vessel reconstruction. Methods The arch-first technique combined with clamshell incision was used in 38 cases of aneurysm and aortic disease in 2008 and 2009. Extensive total arch replacement was used with clamshell incision for reconstruction of arch vessels under deep hypothermic circulatory arrest. Results Overall 30-day mortality was 13%. The mean operating time was approximately 8 hours. Deep hypothermia resulted in mean CPB time exceeding 4.5 hours and mean duration of circulatory arrest was 25 minutes. The overall postoperative temporary and permanent neurologic dysfunction rates were 3% and 3% for elective and 3% and 0% for emergency surgery, respectively. All patients except the five who died in hospital were discharged without nursing care after an average post-operative hospital stay of 35 days. Conclusions The arch-first technique, combined with clamshell incision, provides expeditious replacement of the thoracic aorta with an acceptable duration of hypothermic circulatory arrest and minimizes the risk of retrograde atheroembolism by using antegrade perfusion. PMID:21933402

  6. The impact of surgical site occurrences and the role of closed incision negative pressure therapy.

    PubMed

    Willy, Christian; Engelhardt, Michael; Stichling, Marcus; Grauhan, Onnen

    2016-09-01

    Surgical site occurrences are observed in up to 60% of inpatient surgical procedures in industrialised countries. The most relevant postoperative complication is surgical site infection (SSI) because of its impact on patient outcomes and enormous treatment costs. Literature reviews ('SSI', 'deep sternal wound infections' (DSWI), 'closed incision negative pressure wound therapy' (ciNPT) were performed by electronically searching MEDLINE (PubMed) and subsequently using a 'snowball' method of continued searches of the references in the identified publications. Search criteria included publications in all languages, various study types and publication in a peer-reviewed journal. The SSI literature search identified 1325, the DSWI search 590 and the ciNPT search 103 publications that fulfilled the search criteria. Patient-related SSI risk factors (diabetes mellitus, obesity, smoking, hypertension, female gender) and operation-related SSI risk factors (re-exploration, emergency operations, prolonged ventilation, prolonged operation duration) exist. We found that patient- and operation-related SSI risk factors were often different for each speciality and/or operative procedure. Based on the evidence, we found that high-risk incisions (sternotomy and incisions in extremities after high-energy open trauma) are principally recommended for ciNPT use. In 'lower'-risk incisions, the addition of patient-related or operation-related risk factors justifies the application of ciNPT. PMID:27547962

  7. [Forensic medical evaluation of stab-incised wounds caused by knives with point defects].

    PubMed

    Krupin, K N; Leonov, S V

    2011-01-01

    The present experimental study allowed to characterize specific signs of stab-incised wounds caused by knives with operational point defects. Diagnostic coefficients calculated for these macro- and microscopic features facilitate differential diagnostics of the injuries and make it possible to identify a concrete stabbing/cutting weapon with which the wound was inflicted.. PMID:21866847

  8. Wound healing studies of skin incisions in animal models: laser soldering versus other bonding methods

    NASA Astrophysics Data System (ADS)

    Simhon, David; Vasilyev, Tamar; Brosh, Tamar; Nevo, Zvi; Tennenbaum, Tamar; Kariv, Naam; Katzir, Abraham

    2003-06-01

    In the past, we have successfully used laser soldering for bonding cuts in the skin of medium and large size animal models. In this work, we have used the same method for bonding cuts on the backs of rabbits and mature pigs model. Cuts were created in dorsally depilated skins of rabbits and mature pigs. 47% bovine serum albumin (BSA) solder was applied onto the approximated edges of each cut, using a special approximation device. An infrared fiberoptic CO2 laser system was used to heat a spot on the cut, under good temperature control, to 65°C for 10 seconds. Other glued or sutured cuts, served as controls. Immediate tensile strength measurements were done on bonded incisions in rabbit skins. We found that laser soldered incisions exhibited similar strength to one bonded by cayanoacrylate glue. No dehiscence of wound edges was found in both treatments. The laser soldering procedure was 25% faster then suturing. A 14-day follow up of the bonded pig skin incisions was carried out, using punch biopsies. We found better aesthetic appearance of the soldered incisions. We observed better and faster wound repair in the laser-soldered scars, using histological and molecular staining. The temperature controlled laser soldering offers immediate strength similar to that of cyanoacrylate glues and better aesthetic and wound healing properties, in comparison to suturing techniques. We have clearly demonstrated the potential of this novel technique, which will pave thw way for clinical studies.

  9. Comparison of Minimal Skin Incision Technique in Living Kidney Transplantation and Conventional Kidney Transplantation

    PubMed Central

    Kim, Sang-Dong; Kim, Ji-Il; Moon, In-Sung; Park, Sun-Cheol

    2016-01-01

    Background: Recently, the most common incision for kidney transplantation (KT) is an inverted J-shaped incision known as the “hockey-stick.” However, demands for minimally invasive surgery in KT are increasing as in other various fields of surgery. Hence, we evaluated whether there is difference between minimal skin incision technique in kidney transplantation (MIKT) and conventional KT (CKT). Methods: Between June 2006 and March 2013, a total of 452 living kidney transplant patients were enrolled. The MIKT group included 17 young unmarried women whose body mass index was <25 kg/m2 and had no anatomic variation. The CKT group included 435 patients. The MIKT operation technique restricted to the 10 cm-sized skin incision in the lower right abdomen from laterally below the anterior superior iliac spine to the midline just above the pubis was performed. We compared the baseline clinical characteristics and postoperative results between two groups. For proper comparison, propensity score matching was implemented. Results: There was no difference in graft function, survival, and postoperative complication rate between MIKT and CKT groups (all P > 0.05). The 5-year graft survival was 92.3% and 85.7% in MIKT and CKT groups, respectively (P = 0.786). Conclusions: Our results indicated that MIKT showed more favorable cosmetic results, and there were no statistical differences in various postoperative factors including graft function, survival, and complications compared with CKT. Hence, we suggested that MIKT is an appropriate method for selected patients in living KT. PMID:27064035

  10. The influence of incisal malocclusion on the social attractiveness of young adults in Finland.

    PubMed

    Kerosuo, H; Hausen, H; Laine, T; Shaw, W C

    1995-12-01

    The aim of this study was to investigate the importance of dentofacial appearance on the perceived social attractiveness of young adults in Finland. The dental arrangements studied were incisal crowding, median diastema, protruding incisors, and ideal incisal occlusion. Facial photographs of six young adults were obtained and modified, so that for each face, four different dental arrangements could be portrayed. The photographs were shown to 1007 Finnish students to estimate social and personal characteristics of the person in the photograph. Dental arrangement had a significant influence on the perceived beauty and success of the persons. Test faces with incisal crowding and median diastema were ranked as significantly less intelligent, beautiful and sexually attractive, and judged to belong to lower social class than the same faces with ideal occlusion. Protruded incisors did not affect the ratings compared to ideal occlusion. On the average, female test faces were judged more favourably than the male ones. The results indicate that among Finnish students conspicuous incisal crowding or spacing represent a social disadvantage compared to normal or protruded incisors. PMID:8682167

  11. Groundwater-surface water interaction in the riparian zone of an incised channel, Walnut Creek, Iowa

    USGS Publications Warehouse

    Schilling, K.E.; Li, Z.; Zhang, Y.-K.

    2006-01-01

    Riparian zones of many incised channels in agricultural regions are cropped to the channel edge leaving them unvegetated for large portions of the year. In this study we evaluated surface and groundwater interaction in the riparian zone of an incised stream during a spring high flow period using detailed stream stage and hydraulic head data from six wells, and water quality sampling to determine whether the riparian zone can be a source of nitrate pollution to streams. Study results indicated that bank storage of stream water from Walnut Creek during a large storm water runoff event was limited to a narrow 1.6 m zone immediately adjacent to the channel. Nitrate concentrations in riparian groundwater were highest near the incised stream where the unsaturated zone was thickest. Nitrate and dissolved oxygen concentrations and nitrate-chloride ratios increased during a spring recharge period then decreased in the latter portion of the study. We used MODFLOW and MT3DMS to evaluate dilution and denitrification processes that would contribute to decreasing nitrate concentrations in riparian groundwater over time. MT3DMS model simulations were improved with a denitrification rate of 0.02 1/d assigned to the floodplain sediments implying that denitrification plays an important role in reducing nitrate concentrations in groundwater. We conclude that riparian zones of incised channels can potentially be a source of nitrate to streams during spring recharge periods when the near-stream riparian zone is largely unvegetated. ?? 2005 Elsevier B.V. All rights reserved.

  12. Does Transumbilical Incision Influence Surgical Site Infection Rates of the Laparoscopic Sigmoidectomy and Anterior Resection?

    PubMed

    Yamamoto, Masashi; Tanaka, Keitaro; Asakuma, Mitsuhiro; Kondo, Keisaku; Isii, Masatsugu; Hamamoto, Hiroki; Okuda, Junji; Uchiyama, Kazuhisa

    2015-12-01

    Laparoscopic surgery is widespread and is safe and effective for the management of patients with colorectal cancer. However, surgical site infection (SSI) remains an unresolved complication. The present study investigated the comparative effect of supraumbilical incision versus transumbilical incision (TU) on the incidence of SSI in patients undergoing laparoscopic surgery for colon cancer. Medical records from patients with colorectal cancer who underwent laparoscopic sigmoid and rectosigmoid colon surgeries with either supraumbilical incision (n = 150) or TU (n = 150) were retrospectively reviewed. There was no difference in demographics, comorbidities, or operative variables between the two groups. The transumbilical group and the supraumbilical group were comparable with regards to overall SSI (6.0% vs 4.0%; P = 0.4062), superficial SSI (6.0% vs 3.3%; P = 0.2704), and deep SSI (0% vs 0.7%; P = 0.2385). SSI developed after laparoscopic sigmoid and rectosigmoid colon cancer surgery in 15 (5.0%) of the 300 patients. Of these superficial SSI, all wounds were in the left lower quadrant incision, and the transumbilical port sites did not become infected. Univariate analysis failed to identify any risk factors for SSI. Avoidance of the umbilicus offers no benefit with regard to SSI compared with TU. PMID:26736159

  13. RELATIONSHIPS OF MEADOW VEGETATION TO GROUNDWATER DEPTH: EFFECTS OF PRECIPITATION VARIABILITY AND STREAM INCISION

    EPA Science Inventory

    The composition of riparian meadow vegetation is controlled by access to groundwater. Depth to groundwater is controlled by meadow architecture and water source, and changes in either meadow architecture or water source through stream incision or changes in annual precipitation c...

  14. 9 CFR 310.11 - Cleaning of hog carcasses before incising.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Cleaning of hog carcasses before incising. 310.11 Section 310.11 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT... AND VOLUNTARY INSPECTION AND CERTIFICATION POST-MORTEM INSPECTION § 310.11 Cleaning of hog...

  15. Mussel-inspired nanofibrous sheet for suture-less stomach incision surgery.

    PubMed

    Jiang, J; Wan, W; Ge, L; Bu, S; Zhong, W; Xing, M

    2015-05-21

    We report a dopamine-based crosslinker-conjugated gelatin/polycaprolactone nanofibrous sheet. The nanosheet was then employed to treat stomach incisions without sutures during surgery. The mussel-inspired nanosheets, combining the advantages adhesion and tissue repair, show promise for use in treatments of fragile tissues and to avoid suture-caused stress concentration. PMID:25912340

  16. Successful Retrieval of a Retained Capsule Endoscope with Single Incision Laparoscopic Surgery

    PubMed Central

    Tashiro, Yoshihiko; Kawai, Masaya; Takehara, Kazuhiro; Munakata, Shinya; Ishiyama, Shun; Sugimoto, Kiichi; Takahashi, Makoto; Kojima, Yutaka; Goto, Michitoshi; Tomiki, Yuichi; Shibuya, Tomoyoshi; Osada, Taro; Watanabe, Sumio; Sakamoto, Kazuhiro

    2014-01-01

    Capsule endoscopy (CE) is commonly used for examining and diagnosing gastrointestinal disease, especially small bowel disease. Capsule retention is a well-known and significant complication of CE and requires surgical or endoscopic removal. Most reports described the retrieval of retained CE via laparotomy. We report a case of successful retrieval of the capsule using single incision laparoscopic surgery. PMID:25028577

  17. One- Versus Two-Incision Technique for Distal Biceps Tendon Repair

    PubMed Central

    Johnson, Timothy S.; Johnson, David C.; Allen, Answorth A.; Weiland, Andrew J.; Cavanaugh, John; Noonan, Dennis; Lyman, Stephen

    2008-01-01

    There are several techniques that have been described for distal biceps tendon repair but there is still controversy regarding the optimal technique. Our hypothesis is that the single-incision technique will have a similar complication rate and functionally equivalent restoration of function compared with the two-incision approach. A retrospective review of consecutive biceps tendon repairs was performed at one institution over a 5-year period. Thirty-six patients met the inclusion criteria and 26 were available for follow-up including subjective assessment, physical examination, and strength testing. Patients were divided into two groups based on the surgical approach utilized: 12 patients underwent single-incision repair and 14 had a two-incision repair. The average follow-up was 33 months (minimum 13; maximum 75). There were no statistically significant differences in regards to flexion strength or endurance, supination strength or endurance, or complication rates between the two techniques. In conclusion, both surgical techniques led to adequate restoration of strength with a low complication rate. Both techniques are safe to perform and should be guided by surgeon comfort with the approach. PMID:18815854

  18. TRPV1, but not TRPA1, in primary sensory neurons contributes to cutaneous incision-mediated hypersensitivity

    PubMed Central

    2013-01-01

    Background Mechanisms underlying postoperative pain remain poorly understood. In rodents, skin-only incisions induce mechanical and heat hypersensitivity similar to levels observed with skin plus deep incisions. Therefore, cutaneous injury might drive the majority of postoperative pain. TRPA1 and TRPV1 channels are known to mediate inflammatory and nerve injury pain, making them key targets for pain therapeutics. These channels are also expressed extensively in cutaneous nerve fibers. Therefore, we investigated whether TRPA1 and TRPV1 contribute to mechanical and heat hypersensitivity following skin-only surgical incision. Results Behavioral responses to mechanical and heat stimulation were compared between skin-incised and uninjured, sham control groups. Elevated mechanical responsiveness occurred 1 day post skin-incision regardless of genetic ablation or pharmacological inhibition of TRPA1. To determine whether functional changes in TRPA1 occur at the level of sensory neuron somata, we evaluated cytoplasmic calcium changes in sensory neurons isolated from ipsilateral lumbar 3–5 DRGs of skin-only incised and sham wild type (WT) mice during stimulation with the TRPA1 agonist cinnamaldehyde. There were no changes in the percentage of neurons responding to cinnamaldehyde or in their response amplitudes. Likewise, the subpopulation of DRG somata retrogradely labeled specifically from the incised region of the plantar hind paw showed no functional up-regulation of TRPA1 after skin-only incision. Next, we conducted behavior tests for heat sensitivity and found that heat hypersensitivity peaked at day 1 post skin-only incision. Skin incision-induced heat hypersensitivity was significantly decreased in TRPV1-deficient mice. In addition, we conducted calcium imaging with the TRPV1 agonist capsaicin. DRG neurons from WT mice exhibited sensitization to TRPV1 activation, as more neurons (66%) from skin-incised mice responded to capsaicin compared to controls (46%), and the

  19. Rock slope response to fluvial incision in the central Swiss Alps

    NASA Astrophysics Data System (ADS)

    Leith, Kerry; Fox, Matthew; Moore, Jeffrey R.

    2016-04-01

    The longitudinal profile of rivers intersecting the Rhone Valley in the central Swiss Alps suggests the development of topography throughout much of this region has been dominated by interglacial fluvial incision and ongoing tectonic uplift with only minimal glacial erosion since the mid-Pleistocene transition. Evidence indicates bedrock river incision during this period reflects a base level fall of between 500 m and 800 m (depending on the degree of overdeepening following an early period of enhanced glacial incision). This observation raises important questions regarding the preservation, or development of hillslope morphologies through multiple glacial-interglacial cycles. Since the pioneering works of Richter (1900) and Penck and Brückner (1909), Alpine geomorphologists have commented on a sequence of between three and five moderately dipping matched terraces that converge toward inferred paleo-river channels up to 800 m above the axis of many valleys. Here, we use a combination of integral analysis, forward streampower models, and a new method of topographic analysis based on high resolution LiDAR DEMs in order to test the correspondence of valley morphologies in this formerly glaciated landscape, with hillslope processes initiated by fluvial incision up to 700,000 years ago. Results indicate topography adjacent to reaches subjected to transient fluvial incision is characterized by a coherent region of consistently steep slopes, while narrow gorges correspond to rapid incision close to the Rhone valley since MIS 5. A majority of hillslopes converge to our initial fluvial valley floor, or the location of propagating knickpoints. The correspondence between intermediate-level terraces and modeled stages of river incision is, however, currently unclear. These results offer a unique insight into the long-term response of bedrock slopes to varying rates of base level fall, and the cumulative impact of glacial erosion on Alpine valley walls since MIS 11. Penck, A

  20. The Role of Incision and Sedimentation in Continental Gravity Gliding - Insight from Numerical Modelling

    NASA Astrophysics Data System (ADS)

    Riad, H.; Messager, G.; Nivihre, B.

    2010-12-01

    Large scale gravity gliding are usually observed in deltas and passive margins. They imply the rigid translation of a body down a slope, with coeval upslope extension and downslope contraction. Displacement vectors are parallel to a buried detachment plane gently dipping basinward (1-5°). Field examples suggest that gravity gliding could be found in continental domains but contrary to oceanic environments, upslope sedimentation and pore fluid overpressure do not play a major role. These lacks must be compensated. This study investigates mechanisms generating gravity gliding in a continental domains through the use of a two-dimensional (2D) finite-element model and a 2D analytical failure analysis. We focus on the role of tectonic uplifts and the subsequent fluvial incision and sedimentation at the toes of the slopes. The geometries of the numerical models are based on a field example in the Andean foothills of Argentina. Gravity gliding occurs along the long limb of an asymmetric crustal-scale anticline, above a 1000 m depth salt layers. The numerical models simulate the deformations and estimate quantitatively the circumstances under which failure at the head and toe of the frictional-plastic sedimentary cover initiates. Analytical solutions give simplified approximation of the numerical results taking into account many configurations with various values of the incision, sedimentation, internal friction angle and thickness of the décollement layer. The principal effect of the incision and sedimentation is to reduce and strengthen the downslope resistance to the contractional failure. Consequently, the magnitude of the critical slope for which the gravity gliding initiates, is reduced by the incision and is increased by the sedimentation. Results show that large-scale gravity gliding can be found in continental domains as a consequence of tectonic uplifts and where overburden thickness is lower than 2000 m. Incision facilitates and localizes the gliding

  1. External sclerostomy with the femtosecond laser versus a surgical knife in rabbits

    PubMed Central

    Shi, Yao; Yang, Xiao-Bo; Dai, Neng-Li; Long, Hua; Lu, Pei-Xiang; Jin, Ling; Jiang, Fa-Gang

    2012-01-01

    AIM To experimentally compare the external sclerostomy produced using a femtosecond laser with that made by a surgical knife and to evaluate the healing patterns, efficacy and technical advantages of femtosecond laser sclerostomy. METHODS In a prospective randomized, controlled, masked-observer study, 10 pigmented rabbits underwent external sclerostomy with a femtosecond laser in the right eye; 10 additional rabbits underwent sclerostomy with a surgical superblade in the right eye. Clinical characteristics, which included bleb morphology and intraocular pressure, were recorded for 1 month after surgery. Six additional rabbits underwent external femtosecond laser sclerostomy in the right eye and mechanical sclerostomy in the left eye and were killed at day 14 after surgery. Histologic staining, immunohistochemistry and scanning electron microscopy were subsequently performed to assess the morphology of the filtering fistula. The titanium-sapphire femtosecond laboratory laser was operating at a repetition rate of 1 kHz, 0.4 mJ pulse energy, a central wavelength of 800nm and a pulse duration of 50 femtoseconds. Mann-Whitney and Kaplan-Meier tests were used for statistical analysis. RESULTS Successful complete sclerostomy was achieved in each laser-treated eye which was hit only once by the laser. The laser treated time was approximately 15s-16s. In the laser-treated group (n=16), 2 eyes (12%) developed mild hyphema at the site of entry and 8 eyes (50%) showed transient edema in the corneal periphery adjacent to the laser impact zone. The differences between the groups in duration of function blebs and pressure reduction were statistically significant (P=0.025 and 0.016, respectively). The success rate of the laser-treated group was significantly higher than the knife group (P=0.005). Histologically, the subconjunctival connective tissue was loosely arranged with partially patent sclerostomy in the laser-treated eyes at postoperative day 14. This contrasted with the

  2. CyberKnife Boost for Patients with Cervical Cancer Unable to Undergo Brachytherapy

    PubMed Central

    Haas, Jonathan Andrew; Witten, Matthew R.; Clancey, Owen; Episcopia, Karen; Accordino, Diane; Chalas, Eva

    2012-01-01

    Standard radiation therapy for patients undergoing primary chemosensitized radiation for carcinomas of the cervix usually consists of external beam radiation followed by an intracavitary brachytherapy boost. On occasion, the brachytherapy boost cannot be performed due to unfavorable anatomy or because of coexisting medical conditions. We examined the safety and efficacy of using CyberKnife stereotactic body radiotherapy (SBRT) as a boost to the cervix after external beam radiation in those patients unable to have brachytherapy to give a more effective dose to the cervix than with conventional external beam radiation alone. Six consecutive patients with anatomic or medical conditions precluding a tandem and ovoid boost were treated with combined external beam radiation and CyberKnife boost to the cervix. Five patients received 45 Gy to the pelvis with serial intensity-modulated radiation therapy boost to the uterus and cervix to a dose of 61.2 Gy. These five patients received an SBRT boost to the cervix to a dose of 20 Gy in five fractions of 4 Gy each. One patient was treated to the pelvis to a dose of 45 Gy with an external beam boost to the uterus and cervix to a dose of 50.4 Gy. This patient received an SBRT boost to the cervix to a dose of 19.5 Gy in three fractions of 6.5 Gy. Five percent volumes of the bladder and rectum were kept to ≤75 Gy in all patients (i.e., V75 Gy ≤ 5%). All of the patients remain locally controlled with no evidence of disease following treatment. Grade 1 diarrhea occurred in 4/6 patients during the conventional external beam radiation. There has been no grade 3 or 4 rectal or bladder toxicity. There were no toxicities observed following SBRT boost. At a median follow-up of 14 months, CyberKnife radiosurgical boost is well tolerated and efficacious in providing a boost to patients with cervix cancer who are unable to undergo brachytherapy boost. Further follow-up is required to see if these results remain

  3. Reduction of Long-Term Bedrock Incision Efficiency by Short-Term Alluvial Cover Intermittency

    NASA Astrophysics Data System (ADS)

    Lague, D.

    2009-12-01

    Rapid mountain river incision through bedrock is an inherently stochastic process resulting from the long-term summation of flow and sediment discharge events at very variable rates and frequency. While the actual incision processes remains difficult to apprehend in situ and are the subject of ongoing research, there is no ambiguity on the inhibiting effect of a thick alluvial cover (several meters) on bed incision. This alluvial cover thickness strongly fluctuates as a function of stochastic supply of sediment by hillslopes, modulated by sediment transport and storage in the drainage network. Here, I study how this short-term stochasticity propagates into the long-term reduction of bedrock incision efficiency (the cover effect) at geological timescales, and how the upscaled cover model compare to existing empirical models. I introduce a new numerical model (SSTRIM, Stochastic Sediment Transport and River Incision Model) that resolves sediment transport and bedrock incision at daily timescales over a channel reach consisting of several trapezoidal cross-sections linked together. The model is run for thousands of years until a steady-state geometry is reached under the prevailing uplift, sediment supply and water discharge rates. The model incorporates (i) a stochastic sediment supply mimicking the pdf of sediment volume supplied by landsliding, (ii) a transport threshold and daily stochastic variations in water discharge, (iii) a freely evolving channel width and slope; (iv) an explicit treatment of alluvial thickness variations and corresponding bed incision reduction. Bed and bank incision are calculated as a function of bed and bank shear stress. Model results predict the existence of 2 cover dynamics regime: one in which the bed is almost permanently partially covered by sediment, and on in which intermittency dominates. In this later case, the cover effect operates over long-term by modulating the proportion of time where the channel is fully or not covered

  4. Comparison of different approaches to the surgical treatment of penile fractures: quicker return to sexual function with longitudinal incisions.

    PubMed

    Xu, M X; Zhou, Z; Yao, H J; Zhang, K; Da, J; Zhang, M; Wang, Z; Lu, M J

    2016-07-01

    The objective of this study was to compare the long-term clinical outcomes from longitudinal incisions and subcoronal circumferential degloving incisions in the surgical treatment of penile fractures. From July 2001 to July 2014, 23 patients were identified with penile fractures. Fourteen patients underwent longitudinal incisions after ultrasound localization; nine patients underwent subcoronal circumferential degloving incisions. Sexual function was evaluated preoperatively and postoperatively using an abridged International Index of Erectile Function (IIEF) questionnaire. The mean (±s.d.) operative time was 19.1 (±3.9) min in the longitudinal incision group and was 45.1 (±6.5) min in the subcoronal circumferential degloving incision group (P<0.05). The mean (±s.d.) times required to recover sexual function were 35.6 (±6.0) days in the longitudinal incision group and 54.0 (±5.8) days in the circumferential incision group (P<0.05). Six months postoperatively, the erectile functions of all cases were comparable to the level preoperatively except three patients. One patient from each group reported symptoms associated with mild ED, but they experienced satisfying sexual orgasms after psychotherapy for 2 months. Another patient's score on the IIEF-5 declined from 25 to 24 points in the circumferential incision group 10 months postoperatively, and this was associated with maintaining an erection after vaginal penetration. In conclusion, the longitudinal incision may allow quicker return to sexual function but not necessarily improved the long-term clinical outcomes. Furthermore, postoperative psychosocial nursing and psychotherapy should receive more attention. PMID:27193065

  5. Bedrock gorges incising glacial hanging valleys (Western Alps, France): results from morphometric analysis, numerical modeling and 10Be cosmogenic dating

    NASA Astrophysics Data System (ADS)

    Valla, Pierre G.; van der Beek, Peter A.; Lague, Dimitri; Carcaillet, Julien

    2010-05-01

    Bedrock gorges are frequent features in glacial or post-glacial landscapes and allow measurements of fluvial bedrock incision in mountainous relief. Using digital elevation models, aerial photographs, topographic maps and field reconnaissance in the Pelvoux-Ecrins Massif (French Western Alps), we have identified ~30 tributary hanging valleys incised by gorges toward their confluence with the trunk streams. Longitudinal profiles of these tributaries are all convex and have abrupt knickpoints at the upper limit of oversteepened gorge reaches. From morphometric analyses, we find that mean channel gradients and widths, as well as knickpoint retreat rates, display a drainage-area dependence modulated by bedrock lithology. However, there appears to be no relation between horizontal retreat and vertical downwearing of knickpoints. Numerical modeling has been performed to test the capacity of different fluvial incision models to predict the inferred evolution of the gorges. Results from simple end-member models suggest transport-limited behavior of the bedrock gorges. Using a more sophisticated model including dynamic width adjustment and sediment-dependent incision rates, we show that bedrock gorge evolution requires significant supply of sediment from the gorge sidewalls triggered by gorge deepening, combined with pronounced inhibition of bedrock incision by sediment transport and deposition. We then use in-situ produced 10Be cosmogenic nuclides to date and quantify bedrock gorge incision into a single glacial hanging valley (Gorge du Diable). We have sampled gorge sidewalls and the active channel bed to derive both long-term and present-day incision rates. 10Be ages of sidewall profiles reveal rapid incision through the late Holocene (ca 5 ka), implying either delayed initiation of gorge incision after final ice retreat from internal Alpine valleys at ca 12 ka, or post-glacial surface reburial of the gorge. Both modeling results and cosmogenic dating suggest that

  6. Dynamic base level and deterministic climate forcing as a possible explanation for transience in bedrock river incision rates

    NASA Astrophysics Data System (ADS)

    Gallen, S. F.; Pazzaglia, F. J.; Wegmann, K. W.; Pederson, J. L.; Gardner, T. W.

    2014-12-01

    Records of bedrock river incision are commonly used to infer rock uplift under the assumption that rates of these two processes match over the long term (>105 yrs). A recent compilation of 14 bedrock river incision records, however, illustrates a dependence of rate on measured interval on time scales approaching 107 yrs, a characteristic that we term the fluvial Sadler effect. The process(es) responsible for such a fluvial Sadler effect over long time scales is unknown, but it is argued to arise because hiatuses in fluvial incision follow a stochastic, heavy-tailed distribution. If correct, linking river incision and rock uplift becomes more complicated than previously thought. Motivated by pervasive evidence in support of non-stochastic, quasi-cyclic climate forcing as modulating rates of bedrock river incision, we explore the degree to which the fluvial Sadler effect may instead arise by such deterministic forcing. We demonstrate that river incision rate is inherently a time dependent measurement, because the reference frame from which it is calculated (the river profile) is dynamic and not fixed with respect to the geoid. Out of necessity, the modern river profile is often used to calculate river incision. Even when uplift is steady and uniform and incision is modulated by quasi-cyclic, deterministic forcing, the use of this static reference systematically biases calculations of river incision producing a dependence of rate on measured interval that is similar to expectations for a stochastic, heavy-tailed distribution. In such cases, the fluvial Sadler effect persists at all time scales, but is largely minimized at times greater than one period of the longest quasi-cyclic forcing. We conclude that bedrock river incision rate, when modulated by deterministic climatic forcing, provides a reliable proxy for rock uplift rate given integration across at least one glacial-interglacial cycle (>105 yrs) and consideration of the correct local base level datum.

  7. Minimally invasive percutaneous endoscopic 2 levels adjacent lumbar discectomy through 1 portal skin incision: Preliminary study

    PubMed Central

    Kim, Hyeun Sung; Ju, Chang Il; Kim, Seok Won; Kim, Jong Gyue; Lee, Seung Myung; Kim, Byoung Wook

    2015-01-01

    Background: Acute lumbar disc herniation can occur in every lumbar intervertebral disc space and in multiple levels simultaneously. In the cases of 2 levels adjacent lumbar disc herniations of severe unilateral radiculopathic leg pain caused by compression of the nerve roots, respectively, multiple incision or long incision is generally needed for simultaneous removal of disc fragment in 2 levels. Objectives: We proposed the minimally invasive one portal skin incision endoscopic discectomy is effective and safe method to treat 2 levels adjacent lumbar disc herniation. Materials and Methods: We have experimented total 8 cases of 2 levels adjacent lumbar disc herniation having unilateral radiculopathic pain respectively. All cases are 2 levels adjacent lumbar disc herniation. We have tried a percutaneous endoscopic transforaminal approach through minimal one portal skin incision and remove the two herniated disc materials in the adjacent levels. Results: The L2-L3 level was involved in 2 patients, L3-L4 level in 6 patients, while the L4-L5 level was involved in 7 patients, L5-S1 level in 1 patient. The mean follow-up was 18.5 months. The mean visual analogue score (VAS) of the patients prior to surgery was 7.75, and the mean postoperative VAS was 2.375. According to Macnab's criteria, 3 patients had excellent results, 4 patients had good results, 1 patient had fair results, and no patient had a poor result; satisfactory results were obtained in 87.5% of the cases. Conclusion: The percutaneous endoscopic transforaminal approach through 1 skin portal incision could be effective surgical method in unilateral adjacent 2 levels lumbar disc herniation. PMID:25972937

  8. Mini-incision microdissection testicular sperm extraction: a useful technique for men with cryptozoospermia.

    PubMed

    Alrabeeah, K; Witmer, J; Ruiz, S; AlMalki, A; Phillips, S; Zini, A

    2016-03-01

    Microdissection testicular sperm extraction (micro-TESE) was developed to minimize the testicular injury associated with multiple open TESEs. We sought to evaluate a mini-incision micro-TESE in men with cryptozoospermia and non-obstructive azoospermia (NOA). We conducted a retrospective study of 26 consecutive men with NOA and cryptozoospermia who underwent a primary (first) micro-TESE between March 2015 and August 2015. Final assessment of sperm recovery (reported on the day of intra-cytoplasmic sperm injection (ICSI)) was recorded as (i) successful (available spermatozoa for ICSI) or (ii) unsuccessful (no spermatozoa for ICSI). The decision to perform a mini-incision micro-TESE (with limited unilateral micro-dissection) or standard/extensive (with unilateral or bilateral micro-dissection) was guided by the intra-operative identification of sperm recovery (≥5 spermatozoa) from the first testicle. Overall, sperm recovery was successful in 77% (20/26) of the men. In 37% of the men (8/26), the mini-incision micro-TESE was successful (positive sperm recovery). The remaining 18 men required a standard (extensive) microdissection: 61% (11/18) underwent a unilateral and 39% (7/18) a bilateral micro-TESE. We found that 90% (9/10) of the men with cryptozoospermia and 63% (10/16) of the men with NOA underwent a unilateral (mini or standard micro-TESE). The mini-incision micro-TESE allowed for successful sperm recovery in 60% (6/10) of the men with cryptozoospermia and 13% (2/16) of the men with NOA. The data demonstrate that a mini-incision micro-TESE together with rapid intra-operative assessment and identification of spermatozoa recovery can be useful in men undergoing microTESE, particularly, men with cryptozoospermia. PMID:26743017

  9. High magnitude and rapid incision from river capture: Rhine River, Switzerland

    NASA Astrophysics Data System (ADS)

    Yanites, Brian J.; Ehlers, Todd A.; Becker, Jens K.; Schnellmann, Michael; Heuberger, Stefan

    2013-06-01

    Landscape evolution is controlled by the development and organization of drainage basins. As a landscape evolves, drainage reorganization events can occur via river capture or piracy, whereby one river basin grows at the expense of another. The river downstream of a capture location will generate a transient topographic response as the added water discharge increases sediment transport and erosion efficiency. This erosional response will propagate upstream through both the captured and original river basins. Here we focus on quantifying the impact of drainage reorganization along the Rhine/Aare River system (~45,000 km2) during the late Pliocene/early Pleistocene, where gravel remnants indicate total incision of ~650 m during the last ~4.2 Myr in the region of the recent Aare-Rhine confluence. We develop a numerical model of drainage capture to quantify the range of possible magnitudes of erosion and the transient river response resulting from the reorganization of the Rhine River. The model accounts for both fluvial incision and sediment transport. Our model estimates 400-800 m of river elevation change (lowering profiles) during the last ~4 Myr due to river capture events, providing an important component to the recent exhumation budget of the Swiss Alpine Foreland. The model indicates a rapid response to capture events (re-equilibration timescale of ~1 Myr). The predicted incision magnitudes are consistent with incision measured from the elevation of Pliocene and early Pleistocene river gravels, suggesting that across northern Switzerland, a significant amount of incision can be explained by drainage reorganization.

  10. Pfannenstiel incision for intact specimen extraction in laparoscopic transperitoneal radical nephrectomy: a longitudinal prospective outcome study

    PubMed Central

    Binsaleh, Saleh; Alomar, Mohammad; Madbouly, Khaled

    2015-01-01

    OBJECTIVES: To evaluate the intra- and postoperative outcomes of patients undergoing laparoscopic radical nephrectomy with intact specimen extraction through a Pfannenstiel transverse suprapubic incision. METHODS: Prospective follow-up of 26 laparoscopic transperitoneal radical nephrectomies for suspected renal tumors in which the kidneys were extracted via a Pfannenstiel lower abdominal transverse incision. RESULTS: The mean operating time was 152.3 (80–255) minutes, and the mean blood loss was 90 (20–300) ml. The mean extraction time was 20.4 (12–35) minutes. The mean weight of the removed specimen was 631.5 (190–1505) grams, and the mean longest diameter of the extracted specimen was 17.4 (9–25) cm. The mean extraction incision size was 10.7 (7–16) cm. No open surgical conversions were necessary. Pain control was excellent, with minimal intravenous morphine equivalent narcotic use by patients: 15.7 (0–31) mg in the recovery room, 33.8 (0–127) mg on the first postoperative day and 8.7 (0–60) mg in the first week after discharge. The patients experienced a short duration to full ambulation and normal dietary intake. Postoperative follow-up visits were recorded for at least six months. The patients reported a high cosmetic satisfaction rate of 97.7% (60–100). No late postoperative complications were observed related to the extraction site. CONCLUSIONS: The operative specimen can be extracted via a low transverse Pfannenstiel incision during radical laparoscopic nephrectomy. This incision ensures the extraction of large specimens while preserving the aesthetic and functional advantages of laparoscopy without increasing the cancer risk. The absence of muscle cutting maintains the integrity of the abdominal wall and elicits minimal pain. No postoperative incisional hernias or keloid formations were observed. PMID:26222816

  11. Contribution of the Chemokine CCL2 to Mechanical Hypersensitivity Following Surgical Incision in Rats

    PubMed Central

    Peters, Christopher M.; Eisenach, James C.

    2010-01-01

    Background Neural-glial signaling in the spinal cord may underlie pain and sensitization after peripheral injury. Here we test the role of a glial activator, the chemokine CCL2 on mechanical hypersensitivity following plantar incision in a rat model of postoperative pain. Methods Twenty four hours after hindpaw incision rats were intrathecally administered an anti-CCL2 neutralizing antibody (3 μg and 10 μg) or control IgG (10 μg). Mechanical hypersensitivity was assessed acutely and for several days following administration of anti-CCL2 antibody using von Frey filaments. Immunohistochemical analysis was conducted on spinal cord sections to examine the effects of treatment on measures of microglial activation including levels of ionized calcium binding adaptor molecule 1 (IBA1) and phosphorylated p38 mitogen activated protein kinase. Results Neutralization of spinal CCL2 acutely reversed mechanical hypersensitivity within 30 minutes in a dose dependent manner. A single administration also produced a sustained decrease in mechanical hypersensitivity 48 and 72 hours following incision. Anti-CCL2 antibody reduced microglial activation as measured by the levels of IBA1 immunoreactivity and the number of microglia containing phosphorylated p38 mitogen activated protein kinase 48 hours following incision but not within 30 minutes of administration. Conclusions These results provide evidence that CCL2 contributes to the maintenance of mechanical hypersensitivity following plantar incision and establishes a role for neural glial signaling in postoperative pain. The long term effects of anti-CCL2 treatment correlate with reduced microglial activation. Spinal blockade of CCL2 may serve as a useful therapy for the treatment of certain aspects of postoperative pain. PMID:20395830

  12. Relaxation phenomenon in composite materials

    NASA Astrophysics Data System (ADS)

    Moznine, R. El.; Blanc, F.; Lieutier, M.; Lefort, A.

    1998-08-01

    Dielectric measurement characteristics such as the dissipation factor, relative permittivity and conductivity as a function of temperature and frequency have been achieved on composite materials based on different epoxy resins filled with alumina inclusions. The analysis of the results show the presence of porosity and inhomogeneity in these materials. The study of the dissipation factor, as a function of temperature at high frequencies, has shown an unexpected absorption phenomenon in materials designed to be utilized as electrical insulators. The identification of the entities responsible for this relaxation shows that the entities result from one of the components of the material. These results can also confirm the inhomogeneity of the materials.

  13. Image compression using constrained relaxation

    NASA Astrophysics Data System (ADS)

    He, Zhihai

    2007-01-01

    In this work, we develop a new data representation framework, called constrained relaxation for image compression. Our basic observation is that an image is not a random 2-D array of pixels. They have to satisfy a set of imaging constraints so as to form a natural image. Therefore, one of the major tasks in image representation and coding is to efficiently encode these imaging constraints. The proposed data representation and image compression method not only achieves more efficient data compression than the state-of-the-art H.264 Intra frame coding, but also provides much more resilience to wireless transmission errors with an internal error-correction capability.

  14. Optical knife-edge displacement sensor for high-speed atomic force microscopy

    SciTech Connect

    Braunsmann, Christoph; Schäffer, Tilman E.; Prucker, Veronika

    2014-03-10

    We show that an optical knife-edge technique can be used to detect the parallel shift of an object with sub-nanometer resolution over a wide bandwidth. This allows to design simple, contact-free, and high-speed displacement sensors that can be implemented in high-speed atomic force microscope scanners. In an experimental setup, we achieved a root-mean-square sensor noise of 0.8 nm within a bandwidth from 1 Hz to 1.1 MHz. We used this sensor to detect and correct the nonlinear z-piezo displacement during force curves acquired with rates of up to 5 kHz. We discuss the fundamental resolution limit and the linearity of the sensor.

  15. Noncontact measurement of liquid-surface properties with knife-edge electric field tweezers technique

    NASA Astrophysics Data System (ADS)

    Shimokawa, Yuji; Sakai, Keiji

    2013-06-01

    We have developed a technique for the simultaneous measurement of the surface tension and the viscosity of a liquid in a noncontact manner. In this method, a small linear deformation of the liquid surface is induced by a local dielectric force that is brought about by a knife-edge electrode. The surface tension and the viscosity are obtained from the shape of the induced meniscus and from the dynamic response of the surface, respectively. The surface tension obtained was examined in comparison with the values measured by the Wilhelmy plate method. We also measured time constants of the surface deformation for a variety of standard viscosity samples and obtained the relation between the time constant and the viscosity. The demonstrated advantage of the system is the ability to uniquely determine the surface tension and the viscosity.

  16. In situ tomography of femtosecond optical beams with a holographic knife-edge

    NASA Astrophysics Data System (ADS)

    Strohaber, J.; Kaya, G.; Kaya, N.; Hart, N.; Kolomenskii, A. A.; Paulus, G. G.; Schuessler, H. A.

    2011-07-01

    We present an in situ beam characterization technique to analyze femtosecond optical beams in a folded version of a 2f-2f setup. This technique makes use of a two-dimensional spatial light modulator (SLM) to holographically redirect radiation between different diffraction orders. This manipulation of light between diffraction orders is carried out locally within the beam. Because SLMs can withstand intensities of up to I˜1011 W/cm2, this makes them suitable for amplified femtosecond radiation. The flexibility of the SLM was demonstrated by producing a diverse assortment of ``soft apertures'' that are mechanically difficult or impossible to reproduce. We test our method by holographically knife-edging and tomographically reconstructing both continuous wave and broadband radiation in transverse optical modes.

  17. Noncontact measurement of liquid-surface properties with knife-edge electric field tweezers technique.

    PubMed

    Shimokawa, Yuji; Sakai, Keiji

    2013-06-01

    We have developed a technique for the simultaneous measurement of the surface tension and the viscosity of a liquid in a noncontact manner. In this method, a small linear deformation of the liquid surface is induced by a local dielectric force that is brought about by a knife-edge electrode. The surface tension and the viscosity are obtained from the shape of the induced meniscus and from the dynamic response of the surface, respectively. The surface tension obtained was examined in comparison with the values measured by the Wilhelmy plate method. We also measured time constants of the surface deformation for a variety of standard viscosity samples and obtained the relation between the time constant and the viscosity. The demonstrated advantage of the system is the ability to uniquely determine the surface tension and the viscosity. PMID:23848774

  18. Gamma knife surgery for a hemangioma of the cavernous sinus in a child.

    PubMed

    Murphy, Rory K J; Reynolds, Matthew R; Mansur, David B; Smyth, Matthew D

    2013-01-01

    Cavernous sinus (CS) hemangiomas are rare vascular abnormalities that constitute 0.4%-2% of all lesions within the CS. Cavernous sinus hemangiomas are high-flow vascular tumors that tend to hemorrhage profusely during resection, leading to incomplete resection and high morbidity and mortality. While Gamma Knife surgery (GKS) has proven to be an effective treatment of CS hemangiomas in the adult population, few reports of GKS for treatment of CS hemangiomas exist in the pediatric literature. Here, the authors present the first case of a 15-year-old girl with a biopsy-proven CS hemangioma who achieved complete resolution of her symptoms and a complete imaging-defined response following GKS. If suspicion for a CS hemangioma is high in a pediatric patient, GKS may be considered as an effective treatment modality, thus avoiding the morbidities of open resection. PMID:23082966

  19. [Characteristics of gunshot wounds caused by the special forces shooting knife (NRS and NRS-2)].

    PubMed

    Isakov, V D; Dyskin, E A; Panchuk, Iu P; Zlodeev, N A

    2004-01-01

    Gunshot wounds of skin and long cortical bones inflicted by the special intelligence knife (NRS and NRS-2: special silent cartridges SP-3 and SP-4) from different distances were examined. Stereomicroscopy, emission spectral analysis, contact-diffusion method and regression- step-by-step analysis were made use of within the case study. A lack of mechanical, thermal or chemical impact from firing gas and of fire soot as well as presence of particles of rubber, copper and sealing varnish, i.e. the most informative shot products, were found to be the main distinctive features in the said wounds. The data obtained can be used in the differential diagnosis of a type and model of the used gun. PMID:15648916

  20. Supernova hemorrhage: obliterative hemorrhage of brain arteriovenous malformations following γ knife radiosurgery.

    PubMed

    Alexander, Matthew D; Hetts, Steven W; Young, William L; Halbach, Van V; Dowd, Christopher F; Higashida, Randall T; English, Joey D

    2012-09-01

    Hemorrhage represents the most feared complication of cerebral arteriovenous malformations (AVMs) in both untreated patients and those treated with gamma knife radiosurgery. Radiosurgery does not immediately lead to obliteration of the malformation, which often does not occur until years following treatment. Post-obliteration hemorrhage is rare, occurring months to years after radiosurgery, and has been associated with residual or recurrent AVM despite prior apparent nidus elimination. Three cases are reported of delayed intracranial hemorrhage in patients with cerebral AVMs treated with radiosurgery in which no residual AVM was found on catheter angiography at the time of delayed post-treatment hemorrhage. That the pathophysiology of these hemorrhages involves progressive venous outflow occlusion is speculated and the possible mechanistic link to subsequent vascular rupture is discussed. PMID:21990534

  1. Electromagnetic Casimir forces of parabolic cylinder and knife-edge geometries

    SciTech Connect

    Graham, Noah; Shpunt, Alexander; Kardar, Mehran; Emig, Thorsten; Rahi, Sahand Jamal; Jaffe, Robert L.

    2011-06-15

    An exact calculation of electromagnetic scattering from a perfectly conducting parabolic cylinder is employed to compute Casimir forces in several configurations. These include interactions between a parabolic cylinder and a plane, two parabolic cylinders, and a parabolic cylinder and an ordinary cylinder. To elucidate the effect of boundaries, special attention is focused on the 'knife-edge' limit in which the parabolic cylinder becomes a half-plane. Geometrical effects are illustrated by considering arbitrary rotations of a parabolic cylinder around its focal axis, and arbitrary translations perpendicular to this axis. A quite different geometrical arrangement is explored for the case of an ordinary cylinder placed in the interior of a parabolic cylinder. All of these results extend simply to nonzero temperatures.

  2. An analysis of simplified solutions for multiple knife-edge diffraction

    NASA Astrophysics Data System (ADS)

    Giovaneli, C. L.

    1984-03-01

    A consideration of the diffraction angles used for the case of two knife-edge obstacles shows the pessimism of the solution proposed by Deygout in the determination of the total path loss when the hills have the same individual loss and are close to each other. This consideration is used to discuss a new approximation to compute the multiple diffraction losses of VHF/UHF radio waves over sharp ridges or hills, which yields very good estimates of the received signal level. The analytical basis for the method of Deygout, taking into account the rigorous spectral diffraction theory outside the transition regions surrounding the shadow boundaries, is used to explain the suggested modification. Two example paths are presented and an error smaller than 0.9 dB between the predictions and the measured values has been reported.

  3. Right thoracoabdominal stab injury penetrating the liver and gallbladder: case report and lessons in penetrating knife wounds to the chest and abdomen

    PubMed Central

    Griffiths, Ewen A; Mohamed, Ahmed; Ball, Chris S

    2010-01-01

    The authors report a patient who suffered a penetrating knife injury to the right thoracoabdominal region which penetrated through the liver and both sides of the gallbladder. This injury was treated successfully by laparotomy and cholecystectomy. PMID:22778183

  4. Gamma Knife Radiosurgery for Skull Base Meningiomas: Long-Term Radiologic and Clinical Outcome

    SciTech Connect

    Han, Jung Ho; Kim, Dong Gyu Chung, Hyun-Tai; Park, Chul-Kee; Paek, Sun Ha; Kim, Chae-Yong; Jung, Hee-Won

    2008-12-01

    Purpose: To analyze the long-term outcomes in patients with skull base meningiomas (SBMNGs) treated with Gamma Knife radiosurgery (GKRS). Methods and Materials: Of the 98 consecutive patients with SBMNGs treated with GKRS between 1998 and 2002, 63 were followed up for more than 48 months. The mean ({+-}SD) age of the patients was 50 {+-} 12 years, the mean tumor volume was 6.5 cm{sup 3} (range, 0.5-18.4 cm{sup 3}), the mean marginal dose was 12.6 Gy (range, 7.0-20.0 Gy), and the mean follow-up duration was 77 {+-} 18 months. The mean number of shots was 13.7 {+-} 3.8. The tumor volume was decreased at the last follow-up in 28 patients (44.4%) and increased in 6 (9.6%). The actuarial tumor control rate was 90.2% at 5 years. No notable prognostic factor related to tumor control was identified. Ten patients (15.9%) with a cranial neuropathy showed unfavorable outcomes. The rate of improvement in patients with a cranial neuropathy was 45.1%. Age >70 years was likely correlated with an unfavorable outcome in patients with cranial neuropathy (odds ratio = 0.027; p = 0.025; 95% confidence interval 0.001-0.632). Cavernous sinus location was significantly associated with improvement of a cranial neuropathy (odds ratio = 7.314; p = 0.007; 95% confidence interval 1.707-31.34). Conclusions: Gamma Knife radiosurgery is an effective modality for the treatment of SBMNGs and provides favorable outcomes in patients with cranial neuropathy, even in the long-term follow-up period. However, radiosurgery for patients with no or only mild symptoms should be performed cautiously because neither complication rate is low enough to be negligible, especially in elderly patients. A cranial neuropathy by MNGs involving the cavernous sinus seems to have a higher chance of improvement after radiosurgery than other SBMNGs.

  5. Bulk density and compaction behavior of knife mill chopped switchgrass,wheat straw, and corn stover

    SciTech Connect

    Chevanan, Nehru; Womac, A.R.; Bitra, V.S.P.; Igathinathane, C.; Yang, Y.T.; Miu, P.I; Sokhansanj, Shahabaddine

    2009-08-01

    Bulk density of comminuted biomass significantly increased by vibration during handling and transportation, and by normal pressure during storage. Compaction characteristics affecting the bulk density of switchgrass, wheat straw, and corn stover chopped in a knife mill at different operating conditions and using four different classifying screens were studied. Mean loose-filled bulk densities were 67.5 18.4 kg/m3 for switchgrass, 36.1 8.6 kg/m3 for wheat straw, and 52.1 10.8 kg/m3 for corn stover. Mean tapped bulk densities were 81.8 26.2 kg/m3 for switchgrass, 42.8 11.7 kg/m3 for wheat straw, and 58.9 13.4 kg/m3 for corn stover. Percentage changes in compressibility due to variation in particle size obtained from a knife mill ranged from 64.3 to 173.6 for chopped switchgrass, 22.2 51.5 for chopped wheat straw and 42.1 117.7 for chopped corn stover within the tested consolidation pressure range of 5 120 kPa. Pressure and volume relationship of chopped biomass during compression with application of normal pressure can be characterized by the Walker model and Kawakita and Ludde model. Parameter of Walker model was correlated to the compressibility with Pearson correlation coefficient greater than 0.9. Relationship between volume reduction in chopped biomass with respect to number of tappings studied using Sone s model indicated that infinite compressibility was highest for chopped switchgrass followed by chopped wheat straw and corn stover. Degree of difficulty in packing measured using the parameters of Sone s model indicated that the chopped wheat straw particles compacted very rapidly by tapping compared to chopped switchgrass and corn stover. These results are very useful for solving obstacles in handling bulk biomass supply logistics issues for a biorefinery.

  6. Evaluation of GAFCHROMIC registered EBT film for CyberKnife registered dosimetry

    SciTech Connect

    Wilcox, Ellen E.; Daskalov, George M.

    2007-06-15

    External beam therapy (EBT) GAFCHROMIC registered film is evaluated for dosimetry and characterization of the CyberKnife registered radiation beams. Percentage depth doses, lateral beam profiles, and output factors are measured in solid water using EBT GAFCHROMIC registered film (International Specialty Products, Wayne, NJ) for the 6 MV radiation beams of diameter 5 to 60 mm produced by the CyberKnife registered (Accuray, Sunnyvale, CA). The data are compared to those measured with the PTW 60008 diode and the Wellhofer CC01 ion chamber in water. For the small radiation field sizes used in stereotactic radiosurgery, lateral electronic disequilibrium and steep dose gradients exist in a large portion of these fields, requiring the use of high-resolution measurement techniques. For small beams, the detector size approaches the dimensions of the beam and adversely affects measurement accuracy in regions where the gradient varies across the detector. When film is the detector, the scanning system is usually the resolution-limiting component. Radiographic films based upon silver halide (AgH) emulsions are widely used for relative dosimetry of external radiation treatment beams in the megavoltage energy range, because of their good spatial resolution and capability to provide integrated dosimetry over two dimensions. Film dosimetry, however, has drawbacks due to its steep energy dependence at low photon energies as well as film processor and densitometer artifacts. EBT radiochromic film, introduced in 2004 specifically for IMRT dosimetry, may be a detector of choice for the characterization of small radiosurgical beams, because of its near-tissue equivalence, radiation beam energy independence, high spatial resolution, and self developing properties. For radiation beam sizes greater than 10 mm, the film measurements were identical to those of the diode and ion chamber. For the smaller beam diameters of 7.5 and 5 mm, however, there were differences in the data measured with

  7. Gamma Knife irradiation method based on dosimetric controls to target small areas in rat brains

    SciTech Connect

    Constanzo, Julie; Paquette, Benoit; Charest, Gabriel; Masson-Côté, Laurence; Guillot, Mathieu

    2015-05-15

    Purpose: Targeted and whole-brain irradiation in humans can result in significant side effects causing decreased patient quality of life. To adequately investigate structural and functional alterations after stereotactic radiosurgery, preclinical studies are needed. The purpose of this work is to establish a robust standardized method of targeted irradiation on small regions of the rat brain. Methods: Euthanized male Fischer rats were imaged in a stereotactic bed, by computed tomography (CT), to estimate positioning variations relative to the bregma skull reference point. Using a rat brain atlas and the stereotactic bregma coordinates obtained from CT images, different regions of the brain were delimited and a treatment plan was generated. A single isocenter treatment plan delivering ≥100 Gy in 100% of the target volume was produced by Leksell GammaPlan using the 4 mm diameter collimator of sectors 4, 5, 7, and 8 of the Gamma Knife unit. Impact of positioning deviations of the rat brain on dose deposition was simulated by GammaPlan and validated with dosimetric measurements. Results: The authors’ results showed that 90% of the target volume received 100 ± 8 Gy and the maximum of deposited dose was 125 ± 0.7 Gy, which corresponds to an excellent relative standard deviation of 0.6%. This dose deposition calculated with GammaPlan was validated with dosimetric films resulting in a dose-profile agreement within 5%, both in X- and Z-axes. Conclusions: The authors’ results demonstrate the feasibility of standardizing the irradiation procedure of a small volume in the rat brain using a Gamma Knife.

  8. Development of a 3-dimensional dosimetry system for Leksell Gamma Knife Perfexion

    NASA Astrophysics Data System (ADS)

    Yoon, KyoungJun; Kwak, JungWon; Lee, DoHeui; Cho, ByungChul; Lee, SangWook; Ahn, SeungDo

    2015-07-01

    The purpose of our study is to develop a new, 3-dimensional dosimetry system to verify the accuracy of dose deliveries in Leksell Gamma Knife Perfexion (LGKP) (Elekta, Norcross, GA, USA). The instrument consists of a moving head phantom, an embedded thin active layer and a CCD camera system and was designed to be mounted to LGKP. As an active material concentrically located in the hemispheric head phantom, we choose Gafchromic EBT3 films and Gd2O2S:Tb phosphor sheets for dosimetric measurements. Also, to compensate for the lack of backscatter, we located a 1-cm-thick poly methyl methacrylate (PMMA) plate downstream of the active layer. The PMMA plate was transparent to scintillation light to reach the CCD with 1200 × 1200 pixels and a 5.2 µm pitch. With this system, 300 images with a 0.2-mm slice gap were acquired under each of three collimator setups, i.e. 4-mm, 8-mm, and 16-mm, respectively. The 2D projected images taken by the CCD camera were compared with the dose distributions measured by the EBT3 films under the same conditions. All 2D distributions were normalized to the maximum values derived by fitting peaks for each collimator setup. The differences in the full widths at half maximum (FWHM) of 2D profiles between CCD images and film doses were measured to be less than 0.3-mm. The scanning task for all peak regions took less than three minutes with the new instrument. So it can be utilized as a QA tool for the Gamma knife radiosurgery system instead of film dosimetry, the use of which requires much more time and many more resources.

  9. Leksell Gamma Knife treatment for pilocytic astrocytomas: long-term results.

    PubMed

    Simonova, Gabriela; Kozubikova, Petra; Liscak, Roman; Novotny, Josef

    2016-07-01

    OBJECTIVE The purpose of this study was to evaluate long-term treatment results, radiation-related toxicity, and prognostic factors for the progression-free survival (PFS) of patients with pilocytic astrocytomas treated by means of stereotactic radiosurgery with a Leksell Gamma Knife. METHODS A total of 25 patients with pilocytic astrocytomas underwent Gamma Knife surgery during the period 1992-2002. The median target volume was 2700 mm(3) (range 205-25,000 mm(3)). The 18 patients treated with 5 daily fractions received a median minimum target dose of 25 Gy. Doses for the 2 patients treated with 10 fractions over 5 days (2 fractions delivered on the same day at least 6 hours apart) were 23 and 28 Gy. For the 5 patients treated with a single fraction, the minimum target dose ranged from 13 to 20 Gy (median 16 Gy). RESULTS Complete regression occurred in 10 patients (40%) and partial regression in 10 patients (40%). The 10-year overall survival rate was 96% and the 10-year PFS rate was 80%. Target volume appeared to be a significant prognostic factor for PFS (p = 0.037). Temporary Grade 3 toxicity appeared in 2 patients (8%), and these patients were treated with corticosteroids for 2 months. Permanent Grade 4 toxicity appeared in 2 patients (8%) and was associated with neurocognitive dysfunction. In these 2 individuals, the neurocognitive dysfunction was also felt to be in part the result of the additional therapeutic interventions (4 in one case and 6 in the other) required to achieve durable control of their tumors. CONCLUSIONS Radiosurgery represents an alternative treatment modality for small residual or recurrent volumes of pilocytic astrocytomas and provides long-term local control. Target volume appears to be the most important factor affecting PFS. PMID:26991883

  10. CyberKnife-based prostate cancer patient radioablation – early results of irradiation in 200 patients

    PubMed Central

    Napieralska, Aleksandra; Namysł-Kaletka, Agnieszka; Głowacki, Grzegorz; Grabińska, Kinga; Woźniak, Grzegorz; Stąpór-Fudzińska, Małgorzata

    2015-01-01

    Introduction Prostrate cancer (PC) is one of the most common malignancies and is frequently treated with an 8-week course of radiotherapy. CyberKnife (CK) based radioablation enables completion of therapy within 5-9 days. The aim of this study is an evaluation of the effectiveness and tolerance of CyberKnife-based radioablation in prostate cancer patients. Material and methods 200 PC patients (94 low risk [LR], 106 intermediate risk [IR]) underwent CK irradiation every other day (fraction dose [fd] 7.25 Gy, total dose [TD] 36.25 Gy, time 9 days). PSA varied from 1.1 to 19.5 (median 7.7) and T stage from T1c to T2c. The percentage of patients with Androgen Deprivation Therapy (ADT), GI (gastrointestinal) and GU (genitourinary) toxicity (EORTC/RTOG scale), and PSA were checked at 1, 4 and 8 months, and thereafter every 6 months – up to a total of 26 months – post-treatment. Results The percentage of patients without ADT increased from 47.5% to 94.1% after 26 months. The maximum percentage of acute G3 adverse effects was 0.6% for GI, 1% for GU and G2 – 2.1% for GI and 8.5% for GU. No late G3 toxicity was observed. The maximum percentage of late G2 toxicity was 0.7% for GI and 3.4% for GU. Median PSA decreased from 7.7 to 0.1 ng/ml during FU. One patient relapsed and was treated with salvage brachytherapy. Conclusions We conclude that CK-based radioablation in low and intermediate risk PC patients is an effective treatment modality enabling OTT reduction and presents a very low percentage of adverse effects. PMID:26568868

  11. Real-time Cherenkov emission portal imaging during CyberKnife® radiotherapy.

    PubMed

    Roussakis, Yiannis; Zhang, Rongxiao; Heyes, Geoff; Webster, Gareth; Mason, Suzannah; Green, Stuart; Pogue, Brian; Dehghani, Hamid

    2015-11-21

    The feasibility of real-time portal imaging during radiation therapy, through the Cherenkov emission (CE) effect is investigated via a medical linear accelerator (CyberKnife(®)) irradiating a partially-filled water tank with a 60 mm circular beam. A graticule of lead/plywood and a number of tissue equivalent materials were alternatively placed at the beam entrance face while the induced CE at the exit face was imaged using a gated electron-multiplying-intensified-charged-coupled device (emICCD) for both stationary and dynamic scenarios. This was replicated on an Elekta Synergy(®) linear accelerator with portal images acquired using the iViewGT(™) system. Profiles across the acquired portal images were analysed to reveal the potential resolution and contrast limits of this novel CE based portal imaging technique and compared against the current standard. The CE resolution study revealed that using the lead/plywood graticule, separations down to 3.4  ±  0.5 mm can be resolved. A 28 mm thick tissue-equivalent rod with electron density of 1.69 relative to water demonstrated a CE contrast of 15% through air and 14% through water sections, as compared to a corresponding contrast of 19% and 12% using the iViewGT(™) system. For dynamic scenarios, video rate imaging with 30 frames per second was achieved. It is demonstrated that CE-based portal imaging is feasible to identify both stationary and dynamic objects within a CyberKnife(®) radiotherapy treatment field. PMID:26513015

  12. Real-time Cherenkov emission portal imaging during CyberKnife® radiotherapy

    NASA Astrophysics Data System (ADS)

    Roussakis, Yiannis; Zhang, Rongxiao; Heyes, Geoff; Webster, Gareth; Mason, Suzannah; Green, Stuart; Pogue, Brian; Dehghani, Hamid

    2015-11-01

    The feasibility of real-time portal imaging during radiation therapy, through the Cherenkov emission (CE) effect is investigated via a medical linear accelerator (CyberKnife®) irradiating a partially-filled water tank with a 60 mm circular beam. A graticule of lead/plywood and a number of tissue equivalent materials were alternatively placed at the beam entrance face while the induced CE at the exit face was imaged using a gated electron-multiplying-intensified-charged-coupled device (emICCD) for both stationary and dynamic scenarios. This was replicated on an Elekta Synergy® linear accelerator with portal images acquired using the iViewGT™ system. Profiles across the acquired portal images were analysed to reveal the potential resolution and contrast limits of this novel CE based portal imaging technique and compared against the current standard. The CE resolution study revealed that using the lead/plywood graticule, separations down to 3.4  ±  0.5 mm can be resolved. A 28 mm thick tissue-equivalent rod with electron density of 1.69 relative to water demonstrated a CE contrast of 15% through air and 14% through water sections, as compared to a corresponding contrast of 19% and 12% using the iViewGT™ system. For dynamic scenarios, video rate imaging with 30 frames per second was achieved. It is demonstrated that CE-based portal imaging is feasible to identify both stationary and dynamic objects within a CyberKnife® radiotherapy treatment field.

  13. CyberKnife Radiosurgery – Value as an Adjunct to Surgical Treatment of HCC?

    PubMed Central

    Schoenberg, Markus; Khandoga, Andrey; Stintzing, Sebastian; Trumm, Christoph; Schiergens, Tobias Simon; Angele, Martin; op den Winkel, Mark; Werner, Jens; Rentsch, Markus

    2016-01-01

    Introduction CyberKnife radiosurgery (CK) is an effective tool for the treatment of malignancies. Its greatest potential is in high-dose radiosurgery delivered to targets in organs that move with respiration, e.g., liver tumors. For hepatocellular carcinoma (HCC), however, surgical treatment (resection, transplantation) is most likely to produce long-term survival; for non-resectable tumors, therapies other than radiosurgery are typically recommended. This study evaluated the long-lasting anti-tumor effects of CK combined with surgery in patients with HCC. Materials and methods  Eighteen patients (three women, 15 men) were included in this prospective observational study. They received 21 single-fraction CK treatments (26 Gy). Patient characteristics, treatment effects, tumor response (according to the Response Evaluation Criteria In Solid Tumors (RECIST) grading) and survival were measured for a median period of 29 months. Results Local tumor control was achieved in 15 patients, with complete and partial remission observed in 10 and five patients, respectively. One patient was treated for two separate lesions in one session, and one received three treatments each separated by two-year intervals; both patients are tumor-free. Two patients showed minimal response, and in one patient local tumor viability could not be excluded by MRI. Nine patients had HCC recurrence, all distant to the treated site. Nine patients died during follow-up, including two with clear relation to tumor progress. Tumor-free survival was 79.4% after one year and 29.8% after three years, and the corresponding overall survival was 84.8% and 66%. Conclusion  This study shows the high effectiveness of single-session frameless CyberKnife radiosurgery for treatment of hepatocellular carcinoma and reconfirms previous results of fractioned radiotherapy of HCC. It also demonstrates the potential of radiosurgery to be combined with surgical concepts. PMID:27284498

  14. An efficient method of measuring the 4 mm helmet output factor for the Gamma Knife

    NASA Astrophysics Data System (ADS)

    Ma, Lijun; Li, X. Allen; Yu, Cedric X.

    2000-03-01

    It is essential to have accurate measurements of the 4 mm helmet output factor in the treatment of trigeminal neuralgia patients using the Gamma Knife. Because of the small collimator size and the sharp dose gradient at the beam focus, this measurement is generally tedious and difficult. We have developed an efficient method of measuring the 4 mm helmet output factor using regular radiographic films. The helmet output factor was measured by exposing a single Kodak XV film in the standard Leksell spherical phantom using the 18 mm helmet with 30-40 of its plug collimators replaced by the 4 mm plug collimators. The 4 mm helmet output factor was measured to be 0.876 ± 0.009. This is in excellent agreement with our EGS4 Monte Carlo simulated value of 0.876 ± 0.005. This helmet output factor value also agrees with more tedious TLD, diode and radiochromic film measurements that were each obtained using two separate measurements with the 18 mm helmet and the 4 mm helmet respectively. The 4 mm helmet output factor measured by the diode was 0.884 ± 0.016, and the TLD measurement was 0.890 ± 0.020. The radiochromic film measured value was 0.870 ± 0.018. Because a single-exposure measurement was performed instead of a double-exposure measurement, most of the systematic errors that appeared in the double-exposure measurements due to experimental setup variations were cancelled out. Consequently, the 4 mm helmet output factor is more precisely determined by the single-exposure approach. Therefore, routine measurement and quality assurance of the 4 mm helmet output factor of the Gamma Knife could be efficiently carried out using the proposed single-exposure technique.

  15. Relaxation damping in oscillating contacts

    PubMed Central

    Popov, M.; Popov, V.L.; Pohrt, R.

    2015-01-01

    If a contact of two purely elastic bodies with no sliding (infinite coefficient of friction) is subjected to superimposed oscillations in the normal and tangential directions, then a specific damping appears, that is not dependent on friction or dissipation in the material. We call this effect “relaxation damping”. The rate of energy dissipation due to relaxation damping is calculated in a closed analytic form for arbitrary axially-symmetric contacts. In the case of equal frequency of normal and tangential oscillations, the dissipated energy per cycle is proportional to the square of the amplitude of tangential oscillation and to the absolute value of the amplitude of normal oscillation, and is dependent on the phase shift between both oscillations. In the case of low frequency tangential oscillations with superimposed high frequency normal oscillations, the dissipation is proportional to the ratio of the frequencies. Generalization of the results for macroscopically planar, randomly rough surfaces as well as for the case of finite friction is discussed. PMID:26549011

  16. Relaxation damping in oscillating contacts

    NASA Astrophysics Data System (ADS)

    Popov, M.; Popov, V. L.; Pohrt, R.

    2015-11-01

    If a contact of two purely elastic bodies with no sliding (infinite coefficient of friction) is subjected to superimposed oscillations in the normal and tangential directions, then a specific damping appears, that is not dependent on friction or dissipation in the material. We call this effect “relaxation damping”. The rate of energy dissipation due to relaxation damping is calculated in a closed analytic form for arbitrary axially-symmetric contacts. In the case of equal frequency of normal and tangential oscillations, the dissipated energy per cycle is proportional to the square of the amplitude of tangential oscillation and to the absolute value of the amplitude of normal oscillation, and is dependent on the phase shift between both oscillations. In the case of low frequency tangential oscillations with superimposed high frequency normal oscillations, the dissipation is proportional to the ratio of the frequencies. Generalization of the results for macroscopically planar, randomly rough surfaces as well as for the case of finite friction is discussed.

  17. Incision of the Three Rivers Region, southeastern Tibetan Plateau, using low-temperature thermochronometry

    NASA Astrophysics Data System (ADS)

    Yang, Rong; Herman, Frédéric; Giuditta Fellin, Maria; Valla, Pierre G.; Willett, Sean; Wang, Wei

    2014-05-01

    The time and geodynamic processes of building the Tibetan Plateau are still controversial despite decades of studies. The Three Rivers Region (TRR: (Yangtze, Mekong and Salween rivers), located at the southeastern margin of the Tibetan plateau in China, is characterized by spectacular erosion and relief increase where the old low-relief landscape defining the Tibetan plateau surface is currently being incised by drainage networks. Rapid fluvial incision by the three major rivers and their tributaries has created deep and narrow gorges up to 2 to 3 km in depth along this portion of the plateau margin, promoting efficient hillslope response. However, timing, forcing magnitude and potential triggers for this erosional response are still debated and require precise quantification of landscape evolution in the TRR area. In this study, we report new apatite (U-Th)/He (AHe) and apatite fission track (AFT) ages from this region, collected mainly along the main trunk rivers with the objective of constraining the propagation of river incision from the plateau margin into its interior. Our AHe data range from ~1 to >80 Ma, while our AFT ages are between ~3 and 50 Ma. Old thermochronology ages >20 Ma indicate slow long-term erosion on the Tibetan plateau, while most of the ages along the trunk channels are younger than 10-15 Ma and clearly indicate exhumation related to plateau incision. Zircons are currently being analyzed by (U-Th)/He dating to get better timing for the onset of plateau incision. Composite age-elevation relationships from the three different rivers reveal mean exhumation rates of ~0.15-0.25 km/Ma (AFT and AHe, respectively), for the Mekong river, and apparently higher rates for the Salween and Yangtze rivers (0.7 and 0.4 km/Ma, respectively). After compiling the existing low-temperature thermochronologic data, we used a linear inversion method to investigate the exhumation history in both space and time using the method of Fox et al. (2013). Our results show

  18. Late Quaternary stream incision rates due to tectonic uplift in North Peloponnese, Greece

    NASA Astrophysics Data System (ADS)

    Karymbalis, E.; Ferentinou, M.; Gaki-Papanastassiou, K.; Papanastassiou, D.; Maroukian, H.

    2012-04-01

    This study focuses on defining rates of fluvial incision for the last 350kyrs along valley systems of eight streams (those of Trikalitikos, Katharoneri, Seliandros, Elisson, Assopos, Zapantis, Raizanis and Xerias) that drain the eastern part of the tectonically uplifting area of north Peloponnese. The relationship between incision due to tectonic uplift and surface erosion along these streams is also investigated. The studied rivers have a S.SW-N.NE flow direction and discharge into the Gulf of Corinth. They are developed on the uplifted block of the offshore extension of the Xylokastro normal fault which is one of the main south bounding faults of the elongated asymmetric graben of Gulf of Corinth. A series of ten uplifted marine terraces, ranging in elevation from 10 to 400m, lie on the hanging wall of the Xylokastro normal fault, which have been recognized, mapped in detail and correlated with Late Pleistocene oxygen-isotope stages of high sea-level stands and with global sea-level fluctuations by previous studies. The uplifted Late Pleistocene marine terraces of known age were used as reference surfaces in order to determine fluvial incision rates for the last 350kyrs. The lower reaches of the study streams cut down through these marine terraces To evaluate the incision rates on the uplifted block of the Xylokastro fault 33 topographic cross sections were constructed perpendicular to the valleys at specific locations where streams cut down the marine terraces as close as possible to their inner edges because these points correspond precisely to the age of the palaeo-shoreline during the interglacial stage. The sections were drawn through fieldwork measurements as well as using a digital elevation model (DEM) produced by detailed topographic diagrams at the scale of 1:5,000. These marine platforms allow the reconstruction of the geometry and age of the former (prior the formation of the valley) surface that represents the hypothesized topography in the absence

  19. Dependence of the seal property of ConFlat-type flanges on the fine dimensions of the knife edge

    NASA Astrophysics Data System (ADS)

    Kurokouchi, Satoshi; Shinoda, Satsuo; Morita, Shinsaku

    2003-03-01

    The shape of the sealing face on ConFlat-type flanges has not been addressed at all in the International Standards Organization standards, yet it is the distinct shape of the sealing face on the flange, generally referred to as the "knife edge" that primarily distinguishes the ConFlat sealing system. Results of profiling on the sealing face of 70 mm diameter ConFlat-type flanges, provided by ten individual manufacturers, reveal that while all the sealing faces share a common 20deg angle on the taper face, there are variations in the tip radius of the knife edge, and in the angle of the counterslope against the 20deg taper face. In flange tightening tests using the ConFlat flanges, the tip radius was observed to influence flange penetration into the gasket. It was also determined that the knife edges of all the test flanges were plastically deformed to some extent in the process of tightening twice at a torque of 120 kgf cm. The knife-edge shape was neither found to be dependent on the magnitude of deformation, nor did the deformation have an observable influence on the seal property. In order to closely investigate the dependence of the ConFlat-type flange seal property on the fine shape of its sealing face, four types of 152 mm diameter flanges, each with a different knife-edge shape, were subjected to flange tightening tests. The results indicated that flanges with a small tip radius and a small counterslope angle maintained a satisfactory seal ability, even when applied tightening torque was lower, but had difficulty retaining sealing stability under an elevated temperature. On the other hand, flanges with a large tip radius or large counterslope angle on the knife edge had an advantage in terms of seal stability in baking conditions, but required relatively higher tightening torque to attain secure sealing. To evaluate the tip radius and the counterslope angle at which the flange seal capability and the sealing stability at an elevated temperature are in goo

  20. Using fill terraces to understand incision rates and evolution of the Colorado River in eastern Grand Canyon, Arizona

    NASA Astrophysics Data System (ADS)

    Pederson, Joel L.; Anders, Matt D.; Rittenhour, Tammy M.; Sharp, Warren D.; Gosse, John C.; Karlstrom, Karl E.

    2006-06-01

    The incision and aggradation of the Colorado River in eastern Grand Canyon through middle to late Quaternary time can be traced in detail using well-exposed fill terraces dated by a combination of optically stimulated luminescence, uranium series, and cosmogenic nuclide dating. This fluvial history provides the best bedrock incision rate for this important landscape and highlights the complications and advantages of fill terrace records for understanding river long-profile evolution and incision. The use of fill terraces, as distinct from strath terraces, for calculating incision rates is complicated by the cyclic alluviation and incision they record. In the example of the Grand Canyon this has led to various rates being reported by different workers and rates that tend to be overestimates in shorter records. We illustrate that a meaningful long-term bedrock incision rate of ˜140 m/m.y. can be extracted from the Grand Canyon record by linking episodes when the Colorado River is floored on bedrock. Variable incision rates reported in the greater region may be, to some degree, due to inconsistent calculations. Our data also highlight that the Colorado River has been a mixed alluvial-bedrock river through both time and space and has been a bedrock river for less than half of its Pleistocene history. This strong temporal variation, combined with the varying bedrock the river encounters on its path, heightens the challenge of understanding the tectonic, climatic, and drainage integration controls on the form and evolution of the Colorado River's long profile.