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Sample records for highly conformal treatment

  1. 3-D conformal radiation therapy - Part I: Treatment planning

    International Nuclear Information System (INIS)

    Burman, Chandra M.; Mageras, Gikas S.

    1997-01-01

    Objective: In this presentation we will look into the basic components of 3-dimensional conformal treatment planning, and will discuss planning for some selected sites. We will also review some current and future trends in 3-D treatment planning. External beam radiation therapy is one of the arms of cancer treatment. In the recent years 3-D conformal therapy had significant impact on the practice of external beam radiation therapy. Conformal radiation therapy shapes the high-dose volume so as to conform to the target volume while minimizing the dose to the surrounding normal tissues. The advances that have been achieved in conformal therapy are in part due to the development of 3-D treatment planning, which in turn has capitalized on 3-D imaging for tumor and normal tissue localization, as well as on available computational power for the calculation of 3-D dose distributions, visualization of anatomical and dose volumes, and numerical evaluation of treatment plans. In this course we will give an overview of how 3-D conformal treatments are designed and transferred to the patient. Topics will include: 1) description of the major components of a 3-D treatment planning system, 2) techniques for designing treatments, 3) evaluation of treatment plans using dose distribution displays, dose-volume histograms and normal tissue complication probabilities, 4) implementation of treatments using shaped blocks and multileaf collimators, 5) verification of treatment delivery using portal films and electronic portal imaging devices. We will also discuss some current and future trends in 3-D treatment planning, such as field shaping with multileaf collimation, computerized treatment plan optimization, including the use of nonuniform beam profiles (intensity modulation), and incorporating treatment uncertainties due to patient positioning errors and organ motion into treatment planning process

  2. 94: Treatment plan optimization for conformal therapy

    International Nuclear Information System (INIS)

    Rosen, I.I.; Lane, R.G.

    1987-01-01

    Computer-controlled conformal radiation therapy techniques can deliver complex treatments utilizing large numbers of beams, gantry angles and beam shapes. Linear programming is well-suited for planning conformal treatments. Given a list of available treatment beams, linear programming calculates the relative weights of the beams such that the objective function is optimized and doses to constraint points are within the prescribed limits. 5 refs.; 3 figs

  3. A high-precision system for conformal intracranial radiotherapy

    International Nuclear Information System (INIS)

    Tome, Wolfgang A.; Meeks, Sanford L.; Buatti, John M.; Bova, Francis J.; Friedman, William A.; Li Zuofeng

    2000-01-01

    Purpose: Currently, optimally precise delivery of intracranial radiotherapy is possible with stereotactic radiosurgery and fractionated stereotactic radiotherapy. We report on an optimally precise optically guided system for three-dimensional (3D) conformal radiotherapy using multiple noncoplanar fixed fields. Methods and Materials: The optically guided system detects infrared light emitting diodes (IRLEDs) attached to a custom bite plate linked to the patient's maxillary dentition. The IRLEDs are monitored by a commercially available stereo camera system, which is interfaced to a personal computer. An IRLED reference is established with the patient at the selected stereotactic isocenter, and the computer reports the patient's current position based on the location of the IRLEDs relative to this reference position. Using this readout from the computer, the patient may be dialed directly to the desired position in stereotactic space. The patient is localized on the first day and a reference file is established for 5 different couch positions. The patient's image data are then imported into a commercial convolution-based 3D radiotherapy planning system. The previously established isocenter and couch positions are then used as a template upon which to design a conformal 3D plan with maximum beam separation. Results: The use of the optically guided system in conjunction with noncoplanar radiotherapy treatment planning using fixed fields allows the generation of highly conformal treatment plans that exhibit a high degree of dose homogeneity and a steep dose gradient. To date, this approach has been used to treat 28 patients. Conclusion: Because IRLED technology improves the accuracy of patient localization relative to the linac isocenter and allows real-time monitoring of patient position, one can choose treatment-field margins that only account for beam penumbra and image resolution without adding margin to account for larger and poorly defined setup uncertainty. This

  4. 3D-conformal radiotherapy treatment of high grade gliomas of malignancy

    International Nuclear Information System (INIS)

    Chon Rivas, Ivonne; Chi Ramirez, Daysi; Alert Silva, Jose; Roca Muchuli, Carlos; Leon Gonzalez, Roberto; Perez Penna, Lourdes

    2009-01-01

    Patients diagnosed with high grade gliomas of malignancy (A), have a high mortality rate, about 10% achieve survivals than one year due to poor local control resulting from the inability of high doses of radiation to tumor volume by dose-limiting provided by healthy peritumoral tissues and structures. 3D conformal radiotherapy (RT-3DC) achieves effective tumoricidal high doses with high precision on the tumor with minimal involvement of critical structures near the tumor target volume. From 2005 until 2008 at INOR, a total of 23 patients with histologically confirmed supratentorial gliomas location, histological subtypes of anaplastic astrocytoma (AA) in 8 patients (35%) and Glioblastoma Multiforme (GBM) in 15 patients (65%), aged between 18 and 65, Karnofski scale of 70 or more and total previous surgical resection in 10 patients (43%) or partial in 13 (57%) were included prospectively in this study. The total tumor dose of 66-70 Gy was prescribed with a daily fractionation of 1.8 Gy. All patients underwent CT images (CT) and MRI (MRI) cranial volumes were defined treatment planning according to the concepts of ICRU 50 and 62 with precise immobilization of the head by thermo deformed mask, CT 3mm cuts planning system and 3D treatment planning. Median survival was better in patients younger than 55 years, with high rates of Karnofski, histology of AA and higher percentage of surgical resection. Median survival (Kaplan-Meier method) obtained was 16 months. Survival at 1 and 2 years was 51% and 28% respectively. The RT-3DC can administer higher doses on the tumor with peritumoral healthy protection structures in selected patients with a diagnosis of AA or GBM, increasing local control and potentially overall survival without exacerbating toxicity, thus demonstrating the dose- response of malignant brain tumors. (Author)

  5. Three-dimensional conformal pancreas treatment: comparison of four- to six-field techniques

    International Nuclear Information System (INIS)

    Higgins, Patrick D.; Sohn, Jason W.; Fine, Robert M.; Schell, Michael C.

    1995-01-01

    Purpose: We compare practical conformal treatment approaches to pancreatic cancer using 6 and 18 MV photons and contrast those approaches against standard techniques. Methods and Materials: A four-field conformal technique for treating pancreas cancer has been developed using nonopposed 18 MV photons. This approach has been extended to 6 MV photon application by the addition of one to two fields. These techniques have been optimized to increase sparing of normal liver and bowel, compared with opposed-field methods, to improve patient tolerance of high doses. In this study we compare these techniques in a simulated tumor model in a cylindrical phantom. Dose-volume analysis is used to quantify differences between the conformal, nonopposed techniques with conformal, opposed field methods. This model is also used to evaluate the effect of 1-2 cm setup errors on dose-volume coverage. Results: Dose-volume analysis demonstrates that five-to-six field conformal treatments using 6 MV photons provides similar or better dose coverage and normal tissue sparing characteristics as an optimized 18 MV, four-field approach when 1-2 cm margins are included for setup uncertainty. All approaches using nonopposed beam geometry provide significant reduction in the volume of tissue encompassed by the 30-50% isodose surfaces, as compared with four-field box techniques. Conclusions: Three-dimensional (3D) conformal treatments can be designed that significantly improve dose-volume characteristics over conventional treatment designs without costing unacceptable amounts of machine time. Further, deep intraabdominal sites can be adequately accessed and treated on intermediate energy machines with a relatively moderate increase in machine time

  6. Results of different modes conformal radiotherapy in treatment of cervical cancer

    International Nuclear Information System (INIS)

    Baranovs'ka, L.M.; Yivankova, V.S.; Khrulenko, T.V.; Skomorokhova, T.V.; Gorelyina, G.L.

    2017-01-01

    Development of techniques for cytotoxic treatment applying different modes of conformal radiotherapy, brachytherapy and high-energy (high dose rate - HDR) is one of the promising areas of optimization and efficiency of conservative treatment of patients with regional forms of cervical cancer. At Radiation Oncology Department, National Cancer Institute, 89 patients with stage 2b-3b cervical cancer, aged 29 to 70, underwent examination and combined radiotherapy course. The patients were divided into 2 main groups (56 patients) depending on the mode of developed conformal radiation therapy, and a control group made up by 33 patients (classic, default conformal radiotherapy). Results. Along with external beam radiotherapy, the patients of Group 2 were provided with conformal radiotherapy carried out by means of the linear accelerator of electrons in the mode of enhanced multi fractionation of irradiation dose applied to the small pelvis area (tumor and lymph efflux channels) with the single tumor dose 1.3 Gy twice per day once 4-6 hours up to the total radiation dose of 45 Gy applied to the small pelvis lymph nodes. The patients of Group 1 and the ones of the control group underwent conformal radiotherapy in the mode of standard fractionation applied to the small pelvis area with the single tumor dose of 1.8 Gy up to the total radiation dose of 45 Gy. Conformal radiotherapy was carried out for the patients of Group 1 associated with chemoradiomodifiers (tegafur, cisplatin). At the stage 2 of combined radiotherapy course, all patients underwent HDR brachytherapy via Co60 source in the mode of the single tumor dose of 5 Gy at point A up to the total radiation dose of 35-40 Gy. Therefore, employing accelerated mode of multifractiation in conformal radiotherapy of patients with regional cervical cancer makes it possible to enhance canrcinocidal irradiation doses applied to a tumor, and an interval between radiotherapy fractions provides conditions for initiation of

  7. Conformal radiation therapy with or without intensity modulation in the treatment of localized prostate cancer

    International Nuclear Information System (INIS)

    Maingon, P.; Truc, G.; Bosset, M.; Peignaux, K.; Ammor, A.; Bolla, M.

    2005-01-01

    Conformal radiation therapy has now to be considered as a standard treatment of localized prostatic adenocarcinomas. Using conformational methods and intensity modulated radiation therapy requires a rigorous approach for their implementation in routine, focused on the reproducibility of the treatment, target volume definitions, dosimetry, quality control, setup positioning. In order to offer to the largest number of patients high-dose treatment, the clinicians must integrate as prognostic factors accurate definition of microscopic extension as well as the tolerance threshold of critical organs. High-dose delivery is expected to be most efficient in intermediary risks and locally advanced diseases. Intensity modulated radiation therapy is specifically dedicated to dose escalation. Perfect knowledge of classical constraints of conformal radiation therapy is required. Using such an approach in routine needs a learning curve including the physicists and a specific quality assurance program. (author)

  8. Conformal three dimensional radiotherapy treatment planning in Lund

    International Nuclear Information System (INIS)

    Knoos, T.; Nilsson, P.; Anders, A.

    1995-01-01

    The use of conformal therapy is based on 3-dimensional treatment planning as well as on methods and routines for 3-dimensional patient mapping, 3-dimensional virtual simulation and others. The management of patients at the Radiotherapy Department at the University Hospital in Lund (Sweden) is discussed. About 2100 new patients are annually treated with external radiotherapy using seven linear accelerators. Three of the accelerators have dual photon energies and electron treatment facilities. A multi-leaf collimator as well as an electronic portal imaging device are available on one machine. Two simulators and an in-house CT-scanner are used for treatment planning. From 1988 to 1992 Scandiplan (Umplan) was used. Since 1992, the treatment planning system is TMS (HELAX AB, Sweden), which is based on the pencil beam algorithm of Ahnesjo. The calculations use patient modulated accelerator specific energy fluence spectra which are compiled with pencil beams from Monte Carlo generated energy absorption kernels. Heterogeneity corrections are performed with results close to conventional algorithms. Irregular fields, either from standard or individual blocks and from multi-leaf collimators are handled by the treatment planning system. The field shape is determined conveniently using the beam's eye view. The final field shape is exported electronically to either the block cutting machine or the multileaf collimator control computer. All patient fields are checked against the beam's eye view during simulation using manual methods. Treatment verification is performed by portal films and in vivo dosimetry with silicon diodes or TL-dosimetry. Up to now, approximately 4400 patients have received a highly individualized 3-dimensional conformal treatment

  9. 3-D conformal radiation therapy - Part II: Computer-controlled 3-D treatment delivery

    International Nuclear Information System (INIS)

    Benedick, A.

    1997-01-01

    Purpose/Objective: This course will describe the use of computer-controlled treatment delivery techniques for treatment of patients with sophisticated conformal therapy. In particular, research and implementation issues related to clinical use of computer-controlled conformal radiation therapy (CCRT) techniques will be discussed. The possible/potential advantages of CCRT techniques will be highlighted using results from clinical 3-D planning studies. Materials and Methods: In recent years, 3-D treatment planning has been used to develop and implement 3-D conformal therapy treatment techniques, and studies based on these conformal treatments have begun to show the promise of conformal therapy. This work has been followed by the development of commercially-available multileaf collimator and computer control systems for treatment machines. Using these (and other) CCRT devices, various centers are beginning to clinically use complex computer-controlled treatments. Both research and clinical CCRT treatment techniques will be discussed in this presentation. General concepts and requirements for CCRT will be mentioned. Developmental and clinical experience with CCRT techniques from a number of centers will be utilized. Results: Treatment planning, treatment preparation and treatment delivery must be approached in an integrated fashion in order to clinically implement CCRT treatment techniques, and the entire process will be discussed. Various CCRT treatment methodologies will be reviewed from operational, dosimetric, and technical points of view. The discussion will concentrate on CCRT techniques which are likely to see rather wide dissemination over the next several years, including particularly the use of multileaf collimators (MLC), dynamic and segmental conformal therapy, conformal field shaping, and other related techniques. More advanced CCRT techniques, such as the use of individualized intensity modulation of beams or segments, and the use of computer

  10. Chronic rectal bleeding after high dose conformal treatment of prostate cancer warrants modification of existing morbidity scales

    International Nuclear Information System (INIS)

    Hanlon, A.L.; Schulthiess, T.E.; Hunt, M.A.; Movsas, B.; Peter, R.; Hanks, G.E.

    1996-01-01

    Purpose: Serious late morbidity (Grade (3(4))) from the conformal treatment of prostate cancer has been reported in <1% to 6% of patients. This study demonstrates that the reported frequency of Grade (3(4)) complications varies by the morbidity scale selected and that no existing morbidity scale adequately represents chronic rectal bleeding, which is our most frequent persisting late sequela of high dose conformal treatment. Materials and Methods: Between (5(89)) and (12(93)), 352 patients with T1-3 NXM0 prostate cancers were treated with our 4-field conformal technique without special rectal blocking. This technique includes a 1 cm margin from the CTV to the PTV in all directions. The median follow-up for these patients was 38 mos (4 to 78), and the median ICRU reporting point dose was 74 Gy (63 to 81). Patients are followed at six month intervals, and no patient is lost to follow-up. Three morbidity scales are assessed, the RTOG, the late effects group (LENT), and our modification of the LENT (FC-LENT). This modification registers chronic rectal bleeding requiring more than two coagulations as a grade 3 event. Estimates for Grade (3(4)) late GI complication rates were determined using Kaplan-Meier methodology. Differences in morbidity rates were evaluated using the log-rank test and differences in time to latency of complications were evaluated using the nonparametric Wilcoxon test. The duration of severe symptoms with chronic rectal bleeding is measured from the first to the last transrectal coagulation. Results: Sixteen patients developed Grade (3(4)) complications by one of the three morbidity scales. Two patients required surgery (colostomy, sigmoid resection), 5 required a transfusion, and 9 required more than two coagulations. The median latency to the third coagulation (plus or minus transfusions) was 24 mos (17 to 40). The median duration of bleeding between the first and last coagulation was 6 mos (3 to 25), illustrating the chronicity of this problem

  11. Conformal three dimensional radiotherapy treatment planning in Lund

    Energy Technology Data Exchange (ETDEWEB)

    Knoos, T; Nilsson, P [Lund Univ. (Sweden). Dept. of Radiation Physics; Anders, A [Lund Univ. (Sweden). Dept. of Oncology

    1995-12-01

    The use of conformal therapy is based on 3-dimensional treatment planning as well as on methods and routines for 3-dimensional patient mapping, 3-dimensional virtual simulation and others. The management of patients at the Radiotherapy Department at the University Hospital in Lund (Sweden) is discussed. About 2100 new patients are annually treated with external radiotherapy using seven linear accelerators. Three of the accelerators have dual photon energies and electron treatment facilities. A multi-leaf collimator as well as an electronic portal imaging device are available on one machine. Two simulators and an in-house CT-scanner are used for treatment planning. From 1988 to 1992 Scandiplan (Umplan) was used. Since 1992, the treatment planning system is TMS (HELAX AB, Sweden), which is based on the pencil beam algorithm of Ahnesjo. The calculations use patient modulated accelerator specific energy fluence spectra which are compiled with pencil beams from Monte Carlo generated energy absorption kernels. Heterogeneity corrections are performed with results close to conventional algorithms. Irregular fields, either from standard or individual blocks and from multi-leaf collimators are handled by the treatment planning system. The field shape is determined conveniently using the beam`s eye view. The final field shape is exported electronically to either the block cutting machine or the multileaf collimator control computer. All patient fields are checked against the beam`s eye view during simulation using manual methods. Treatment verification is performed by portal films and in vivo dosimetry with silicon diodes or TL-dosimetry. Up to now, approximately 4400 patients have received a highly individualized 3-dimensional conformal treatment.

  12. Conformal Radiotherapy: Physics, Treatment Planning and Verification. Proceedings book

    Energy Technology Data Exchange (ETDEWEB)

    De Wagter, C [ed.

    1995-12-01

    The goal of conformal radiotherapy is to establish radiation dose distributions that conform tightly to the target volume in view of limiting radiation to normal tissues. Conformal radiotherapy significantly improves both local control and palliation and thus contributes to increase survival and to improve the quality of life. The subjects covered by the symposium include : (1) conformal radiotherapy and multi-leaf collimation; (2) three dimensional imaging; (3) treatment simulation, planning and optimization; (4) quality assurance; and (5) dosimetry. The book of proceedings contains the abstracts of the invited lectures, papers and poster presentations as well as the full papers of these contributions.

  13. Conformal Radiotherapy: Physics, Treatment Planning and Verification. Proceedings book

    International Nuclear Information System (INIS)

    De Wagter, C.

    1995-12-01

    The goal of conformal radiotherapy is to establish radiation dose distributions that conform tightly to the target volume in view of limiting radiation to normal tissues. Conformal radiotherapy significantly improves both local control and palliation and thus contributes to increase survival and to improve the quality of life. The subjects covered by the symposium include : (1) conformal radiotherapy and multi-leaf collimation; (2) three dimensional imaging; (3) treatment simulation, planning and optimization; (4) quality assurance; and (5) dosimetry. The book of proceedings contains the abstracts of the invited lectures, papers and poster presentations as well as the full papers of these contributions

  14. Conformable liquid metal printed epidermal electronics for smart physiological monitoring and simulation treatment

    Science.gov (United States)

    Wang, Xuelin; Zhang, Yuxin; Guo, Rui; Wang, Hongzhang; Yuan, Bo; Liu, Jing

    2018-03-01

    Conformable epidermal printed electronics enabled from gallium-based liquid metals (LMs), highly conductive and low-melting-point alloys, are proposed as the core to achieving immediate contact between skin surface and electrodes, which can avoid the skin deformation often caused by conventional rigid electrodes. When measuring signals, LMs can eliminate resonance problems with shorter time to reach steady state than Pt and gelled Pt electrodes. By comparing the contact resistance under different working conditions, it is demonstrated that both ex vivo and in vivo LM electrode-skin models have the virtues of direct and immediate contact with skin surface without the deformation encountered with conventional rigid electrodes. In addition, electrocardio electrodes composed of conformable LM printed epidermal electronics are adopted as smart devices to monitor electrocardiogram signals of rabbits. Furthermore, simulation treatment for smart defibrillation offers a feasible way to demonstrate the effect of liquid metal electrodes (LMEs) on the human body with less energy loss. The remarkable features of soft epidermal LMEs such as high conformability, good conductivity, better signal stability, and fine biocompatibility represent a critical step towards accurate medical monitoring and future smart treatments.

  15. Treatment accuracy of hypofractionated spine and other highly conformal IMRT treatments

    International Nuclear Information System (INIS)

    Sutherland, B.; Hanlon, P.; Charles, P.

    2011-01-01

    Full text: Spinal cord metastases pose difficult challenges for radiation treatment due to tight dose constraints and a concave PTY. This project aimed to thoroughly test the treatment accuracy of the Eclipse Treatment Planning System (TPS) for highly modulated IMRT treatments, in particular of the thoracic spine, using an Elekta Synergy Linear Accelerator. The increased understanding obtained through different quality assurance techniques allowed recommendations to be made for treatment site commissioning with improved accuracy at the Princess Alexandra Hospital (PAH). Three thoracic spine IMRT plans at the PAH were used for data collection. Complex phantom models were built using CT data, and fields simulated using Monte Carlo modelling. The simulated dose distributions were compared with the TPS using gamma analysis and DYH comparison. High resolution QA was done for all fields using the MatriXX ion chamber array, MapCHECK2 diode array shifted, and the EPlD to determine a procedure for commissioning new treatment sites. Basic spine simulations found the TPS overestimated absorbed dose to bone, however within spinal cord there was good agreement. High resolution QA found the average gamma pass rate of the fields to be 99.1 % for MatriXX, 96.5% for MapCHECK2 shifted and 97.7% for EPlD. Preliminary results indicate agreement between the TPS and delivered dose distributions higher than previously believed for the investigated IMRT plans. The poor resolution of the MatriXX, and normalisation issues with MapCHECK2 leads to probable recommendation of EPlD for future IMRT commissioning due to the high resolution and minimal setup required.

  16. Selection of candidate wells and optimization of conformance treatment design in the Barrancas Field using a 3D conformance simulator

    Energy Technology Data Exchange (ETDEWEB)

    Crosta, Dante; Elitseche, Luis [Repsol YPF (Argentina); Gutierrez, Mauricio; Ansah, Joe; Everett, Don [Halliburton Argentina S.A., Buenos Aires (Argentina)

    2004-07-01

    Minimizing the amount of unwanted water production is an important goal at the Barrancas field. This paper describes a selection process for candidate injection wells that is part of a pilot conformance project aimed at improving vertical injection profiles, reducing water cut in producing wells, and improving ultimate oil recovery from this field. The well selection process is based on a review of limited reservoir information available for this field to determine inter-well communications. The methodology focuses on the best use of available information, such as production and injection history, well intervention files, open hole logs and injectivity surveys. After the candidate wells were selected and potential water injection channels were identified, conformance treatment design and future performance of wells in the selected pilot area were evaluated using a new 3 -D conformance simulator, developed specifically for optimization of the design and placement of unwanted fluid shut-off treatments. Thus, when acceptable history match ing of the pilot area production was obtained, the 3 -D simulator was used to: evaluate the required volume of selected conformance treatment fluid; review expected pressures and rates during placement;. model temperature behavior; evaluate placement techniques, and forecast water cut reduction and incremental oil recovery from the producers in this simulated section of the pilot area. This paper outlines a methodology for selecting candidate wells for conformance treatments. The method involves application of several engineering tools, an integral component of which is a user-friendly conformance simulator. The use of the simulator has minimized data preparation time and allows the running of sensitivity cases quickly to explore different possible scenarios that best represent the reservoir. The proposed methodology provides an efficient means of identifying conformance problems and designing optimized solutions for these individual

  17. Conformation radiotherapy and conformal radiotherapy

    International Nuclear Information System (INIS)

    Morita, Kozo

    1999-01-01

    In order to coincide the high dose region to the target volume, the 'Conformation Radiotherapy Technique' using the multileaf collimator and the device for 'hollow-out technique' was developed by Prof. S. Takahashi in 1960. This technique can be classified a type of 2D-dynamic conformal RT techniques. By the clinical application of this technique, the late complications of the lens, the intestine and the urinary bladder after radiotherapy for the maxillary cancer and the cervical cancer decreased. Since 1980's the exact position and shape of the tumor and the surrounding normal tissues can be easily obtained by the tremendous development of the CT/MRI imaging technique. As a result, various kinds of new conformal techniques such as the 3D-CRT, the dose intensity modulation, the tomotherapy have been developed since the beginning of 1990'. Several 'dose escalation study with 2D-/3D conformal RT' is now under way to improve the treatment results. (author)

  18. Comparing two strategies of dynamic intensity modulated radiation therapy (dIMRT with 3-dimensional conformal radiation therapy (3DCRT in the hypofractionated treatment of high-risk prostate cancer

    Directory of Open Access Journals (Sweden)

    Yartsev Slav

    2008-01-01

    Full Text Available Abstract Background To compare two strategies of dynamic intensity modulated radiation therapy (dIMRT with 3-dimensional conformal radiation therapy (3DCRT in the setting of hypofractionated high-risk prostate cancer treatment. Methods 3DCRT and dIMRT/Helical Tomotherapy(HT planning with 10 CT datasets was undertaken to deliver 68 Gy in 25 fractions (prostate and simultaneously delivering 45 Gy in 25 fractions (pelvic lymph node targets in a single phase. The paradigms of pelvic vessel targeting (iliac vessels with margin are used to target pelvic nodes and conformal normal tissue avoidance (treated soft tissues of the pelvis while limiting dose to identified pelvic critical structures were assessed compared to 3DCRT controls. Both dIMRT/HT and 3DCRT solutions were compared to each other using repeated measures ANOVA and post-hoc paired t-tests. Results When compared to conformal pelvic vessel targeting, conformal normal tissue avoidance delivered more homogenous PTV delivery (2/2 t-test comparisons; p dose, 1–3 Gy over 5/10 dose points; p Conclusion dIMRT/HT nodal and pelvic targeting is superior to 3DCRT in dose delivery and critical structure sparing in the setting of hypofractionation for high-risk prostate cancer. The pelvic targeting paradigm is a potential solution to deliver highly conformal pelvic radiation treatment in the setting of nodal location uncertainty in prostate cancer and other pelvic malignancies.

  19. Three-dimensional (3D) real-time conformal brachytherapy - a novel solution for prostate cancer treatment Part I. Rationale and method

    International Nuclear Information System (INIS)

    Fijalkowski, M.; Bialas, B.; Maciejewski, B.; Bystrzycka, J.; Slosarek, K.

    2005-01-01

    Recently, the system for conformal real-time high-dose-rate brachytherapy has been developed and dedicated in general for the treatment of prostate cancer. The aim of this paper is to present the 3D-conformal real-time brachytherapy technique introduced to clinical practice at the Institute of Oncology in Gliwice. Equipment and technique of 3D-conformal real time brachytherapy (3D-CBRT) is presented in detail and compared with conventional high-dose-rate brachytherapy. Step-by-step procedures of treatment planning are described, including own modifications. The 3D-CBRT offers the following advantages: (1) on-line continuous visualization of the prostate and acquisition of the series of NS images during the entire procedure of planning and treatment; (2) high precision of definition and contouring the target volume and the healthy organs at risk (urethra, rectum, bladder) based on 3D transrectal continuous ultrasound images; (3) interactive on-line dose optimization with real-time corrections of the dose-volume histograms (DVHs) till optimal dose distribution is achieved; (4) possibility to overcome internal prostate motion and set-up inaccuracies by stable positioning of the prostate with needles fixed to the template; (5) significant shortening of overall treatment time; (6) cost reduction - the treatment can be provided as an outpatient procedure. The 3D- real time CBRT can be advertised as an ideal conformal boost dose technique integrated or interdigitated with pelvic conformal external beam radiotherapy or as a monotherapy for prostate cancer. (author)

  20. The treatment of colorectal liver metastases with conformal radiation therapy and regional chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, John M; Lawrence, Theodore S; Walker, Suzette; Kessler, Marc L; Andrews, James C; Ensminger, William D

    1995-05-15

    Purpose: Whole-liver radiation, with or without chemotherapy, has been of modest benefit in the treatment of unresectable hepatic metastases from colorectal cancer. A Phase I/II study combining escalating doses of conformally planned radiation therapy (RT) with intraarterial hepatic (IAH) fluorodeoxyuridine (FdUrd) was performed. Methods and Materials: Twenty-two patients with unresectable hepatic metastases from colorectal cancer, 14 of whom had progressed after previous chemotherapy (2 with prior IAH FdUrd), were treated with concurrent IAH FdUrd (0.2 mg/kg/day) and conformal hepatic radiation therapy (1.5-1.65 Gy/fraction twice a day). The total dose of radiation given to the tumor (48-72.6 Gy) depended on the fraction of normal liver excluded from the high-dose volume. All patients were assessed for response, toxicity, hepatobiliary relapse, and survival. Median potential follow-up was 42 months. Results: Eleven of 22 patients demonstrated an objective response, with the remainder showing stable disease. Actuarial freedom from hepatic progression was 25% at 1 year. The most common acute toxicity was mild to moderate nausea and transient liver function test abnormalities. There were three patients with gastrointestinal bleeding (none requiring surgical intervention) after the completion of treatment. Overall median survival was 20 months. The presence of extrahepatic disease was associated with decreased survival (p < 0.01). Conclusions: Combined conformal radiation therapy and IAH FdUrd can produce an objective response in 50% of patients with hepatic metastases from colorectal cancer. However, response was not durable, and hepatic progression was frequent. Improvements in hepatic tumor control for patients with metastatic colorectal cancer may require higher doses of conformal radiation and/or improved radiosensitization. In an effort to increase radiosensitization, we have recently initiated a clinical trial combining IAH bromodeoxyuridine, a thymidine analog

  1. Conformal treatment of prostate cancer with improved targeting: superior prostate-specific antigen response compared to standard treatment

    Energy Technology Data Exchange (ETDEWEB)

    Corn, Benjamin W; Hanks, Gerald E; Schultheiss, Timothy E; Hunt, Margie A; Lee, W Robert; Coia, Lawrence R

    1995-05-15

    Purpose: Conformal radiation therapy (CRT) decreases the morbidity of prostate cancer treatment, but no published data attest to the improved ability of CRT to control disease. Therefore, we compared Prostate-Specific Antigen (PSA) response at 1 year among similarly staged patients treated by conformal techniques to those treated with conventional approaches, looking for an early indicator of tumor response. Method and Materials: Patients with locally advanced disease were treated by pelvic fields followed by prostate field conedowns; those with early stage/low grade disease received only prostate field irradiation. Between October, 1987 and November, 1991, conventional treatments used rectangular beams with or without corner blocks. Neither urethrography nor immobilization casts were used for conventionally treated patients. Between April, 1989 and December, 1992, conformal treatments have used rigid immobilization and Computed Tomography-based, beams-eye-view field design. As such, our conformal approach allowed improved targeting. Median prescribed doses (minimal doses to the Planning Target Volume) were 70 Gy (66-73 Gy) and 70.2 Gy (64.8-75 Gy) for conventionally and conformally treated patients, respectively. Median daily fraction size was 1.8 Gy for conventional treatment and 2.0 Gy for conformal therapy. Baseline PSA data were available on 170 consecutive patients treated conformally and 90 consecutive patients treated conventionally. Results: Among those receiving only prostatic field irradiation, 12-month PSA values returned to normal in 96% and 85% of conformally and conventionally treated patients, respectively, when normalization was defined as {<=} 4 ng/ml (p < 0.03) and in 76% vs. 55% of patients when PSA normalization was defined as {<=} 1.5 ng/ml (p < 0.02). Among those receiving pelvic irradiation prior to prostatic conedown, PSA normalization ({<=} 4 ng/ml) occurred in 82% and 61% (p < 0.01) of conformally and conventionally treated patients

  2. CT-image based conformal high-dose rate brachytherapy boost in the conservative treatment of stage I - II breast cancer - introducing the procedure

    International Nuclear Information System (INIS)

    Kubaszewska, M.; Skowronek, J.; Chichel, A.; Kanikowski, M.; Dymnicka, M.

    2008-01-01

    Aim: Breast-conserving surgery (BCS) followed by radiotherapy (RT) has become the standard treatment for the majority of patients with early breast cancer. With regard to boost technique some disagreements are found between groups that are emphasizing the value of electron boost treatment and groups pointing out the value of interstitial brachytherapy (BT) boost treatment. We present the preliminary results in treating selected patients with early-stage breast cancer using high-dose-rate brachytherapy (HD R-BT) as a boost after breast conservation therapy (BCT). Materials/Methods: Between January 2006 and August 2007, a total of 58 female patients with first and second stage breast cancer underwent BCT. This therapeutic procedure involves BCS, whole breast radiation therapy (WBRT) and additional irradiation to the tumour bed (boost) using interstitial HDR-BT via flexible implant tubes. A 10 Gy boost dose was received by all patients. The treatment planning was based on CT-guided 3D (three-dimensional) reconstruction of the surgical clips, implant tubes and critical structures localization (skin and ribs). The accuracy of tumour bed localization, the conformity of planning target volume and treated volume were analyzed. Results: The evaluations of implant parameters involved the use of: dose volume histogram (DVH), the volume encompassed by the 100% reference isodose surface (V100%), the high dose volumecalculation (V150%, V200%, V300%), the dose non-uniformity ratio (DNR), and the conformity index (COIN). Our results were as follows: the mean PTV volume, the mean high dose volume (V150%; V200%; V300%), the DNR and COIN mean value were estimated at 57.38, 42.98, 21.38, 7.90, 0.52 and 0.83 respectively. Conclusions: CT-guided 3D HDR-BT is most appropriate for planning the boost procedure after BT especially in large breast volume, in cases with a deep seated tumour bed, as well as in patients with high risk for local recurrences. This technique reduces the

  3. Monte Carlo conformal treatment planning as an independent assessment

    International Nuclear Information System (INIS)

    Rincon, M.; Leal, A.; Perucha, M.; Carrasco, E.; Sanchez-Doblado, F.; Hospital Univ. Virgen Macarena, Sevilla; Arrans, R.; Sanchez-Calzado, J.A.; Errazquin, L.; Medrano, J.C.

    2001-01-01

    The wide range of possibilities available in Radiotherapy with conformal fields cannot be covered experimentally. For this reason, dosimetrical and planning procedures are based on approximate algorithms or systematic measurements. Dose distribution calculations based on Monte Carlo (MC) simulations can be used to check results. In this work, two examples of conformal field treatments are shown: A prostate carcinoma and an ocular lymphoma. The dose distributions obtained with a conventional Planning System and with MC have been compared. Some significant differences have been found. (orig.)

  4. Comparing two strategies of dynamic intensity modulated radiation therapy (dIMRT) with 3-dimensional conformal radiation therapy (3DCRT) in the hypofractionated treatment of high-risk prostate cancer

    International Nuclear Information System (INIS)

    Yuen, Jasper; Rodrigues, George; Trenka, Kristina; Coad, Terry; Yartsev, Slav; D'Souza, David; Lock, Michael; Bauman, Glenn

    2008-01-01

    To compare two strategies of dynamic intensity modulated radiation therapy (dIMRT) with 3-dimensional conformal radiation therapy (3DCRT) in the setting of hypofractionated high-risk prostate cancer treatment. 3DCRT and dIMRT/Helical Tomotherapy(HT) planning with 10 CT datasets was undertaken to deliver 68 Gy in 25 fractions (prostate) and simultaneously delivering 45 Gy in 25 fractions (pelvic lymph node targets) in a single phase. The paradigms of pelvic vessel targeting (iliac vessels with margin are used to target pelvic nodes) and conformal normal tissue avoidance (treated soft tissues of the pelvis while limiting dose to identified pelvic critical structures) were assessed compared to 3DCRT controls. Both dIMRT/HT and 3DCRT solutions were compared to each other using repeated measures ANOVA and post-hoc paired t-tests. When compared to conformal pelvic vessel targeting, conformal normal tissue avoidance delivered more homogenous PTV delivery (2/2 t-test comparisons; p < 0.001), similar nodal coverage (8/8 t-test comparisons; p = ns), higher and more homogenous pelvic tissue dose (6/6 t-test comparisons; p < 0.03), at the cost of slightly higher critical structure dose (D dose , 1–3 Gy over 5/10 dose points; p < 0.03). The dIMRT/HT approaches were superior to 3DCRT in sparing organs at risk (22/24 t-test comparisons; p < 0.05). dIMRT/HT nodal and pelvic targeting is superior to 3DCRT in dose delivery and critical structure sparing in the setting of hypofractionation for high-risk prostate cancer. The pelvic targeting paradigm is a potential solution to deliver highly conformal pelvic radiation treatment in the setting of nodal location uncertainty in prostate cancer and other pelvic malignancies

  5. Conformal sequestering simplified

    International Nuclear Information System (INIS)

    Schmaltz, Martin; Sundrum, Raman

    2006-01-01

    Sequestering is important for obtaining flavor-universal soft masses in models where supersymmetry breaking is mediated at high scales. We construct a simple and robust class of hidden sector models which sequester themselves from the visible sector due to strong and conformally invariant hidden dynamics. Masses for hidden matter eventually break the conformal symmetry and lead to supersymmetry breaking by the mechanism recently discovered by Intriligator, Seiberg and Shih. We give a unified treatment of subtleties due to global symmetries of the CFT. There is enough review for the paper to constitute a self-contained account of conformal sequestering

  6. Factors influencing incidence of acute grade 2 morbidity in conformal and standard radiation treatment of prostate cancer

    International Nuclear Information System (INIS)

    Hanks, Gerald E.; Schultheiss, Timothy E.; Hunt, Margie A.; Epstein, Barry

    1995-01-01

    Purpose: The fundament hypothesis of conformal radiation therapy is that tumor control can be increased by using conformal treatment techniques that allow a higher tumor dose while maintaining an acceptable level of complications. To test this hypothesis, it is necessary first to estimate the incidence of morbidity for both standard and conformal fields. In this study, we examine factors that influence the incidence of acute grade 2 morbidity in patients treated with conformal and standard radiation treatment for prostate cancer. Methods and Materials: Two hundred and forty-seven consecutive patients treated with conformal technique are combined with and compared to 162 consecutive patients treated with standard techniques. The conformal technique includes special immobilization by a cast, careful identification of the target volume in three dimensions, localization of the inferior border of the prostate using the retrograde urethrogram, and individually shaped portals that conform to the Planning Target Volume (PTV). Univariate analysis compares differences in the incidence of RTOG-EORTC grade two acute morbidity by technique, T stage, age, irradiated volume, and dose. Multivariate logistic regression includes these same variables. Results: In nearly all categories, the conformal treatment group experienced significantly fewer acute grade 2 complications than the standard treatment group. Only volume (prostate ± whole pelvis) and technique (conformal vs. standard) were significantly related to incidence of morbidity on multivariate analysis. When dose is treated as a continuous variable (rather than being dichotomized into two levels), a trend is observed on multivariate analysis, but it does not reach significant levels. The incidence of acute grade 2 morbidity in patients 65 years or older is significantly reduced by use of the conformal technique. Conclusion: The conformal technique is associated with fewer grade 2 acute toxicities for all patients. This

  7. 3-D conformal treatment of prostate cancer to 74 Gy vs. high-dose-rate brachytherapy boost: A cross-sectional quality-of-life survey

    International Nuclear Information System (INIS)

    Vordermark, Dirk

    2006-01-01

    The effects of two modalities of dose-escalated radiotherapy on health-related quality of life (HRQOL) were compared. Forty-one consecutive patients were treated with a 3-D conformal (3-DC) boost to 74 Gy, and 43 with high-dose rate (HDR) brachytherapy boost (2x9 Gy), following 3-D conformal treatment to 46 Gy. Median age was 70 years in both groups, median initial PSA was 7.9 μg/l in 3-DC boost patients and 8.1 μg/l in HDR boost patients. Stage was 7 in 52% and 47%, respectively. HRQOL was assessed cross-sectionally using EORTC QLQ-C30 and organ-specific PR25 modules 3-32 (median 19) and 4-25 (median 14) months after treatment, respectively. Questionnaires were completed by 93% and 97% of patients, respectively. Diarrhea and insomnia scores were significantly increased in both groups. In the PR25 module, scores of 3-DC boost and HDR boost patients for urinary, bowel and treatment-related symptoms were similar. Among responders, 34% of 3-DC boost patients and 86% of HDR boost patients had severe erectile problems. Dose escalation in prostate cancer by either 3-DC boost to 74 Gy or HDR brachytherapy boost appears to result in similar HRQOL profiles

  8. Comparative dosimetric study of three-dimensional conformal, dynamic conformal arc, and intensity-modulated radiotherapy for brain tumor treatment using Novalis system

    International Nuclear Information System (INIS)

    Ding Meisong; Newman, Francis M.S.; Kavanagh, Brian D.; Stuhr, Kelly M.S.; Johnson, Tim K.; Gaspar, Laurie E.

    2006-01-01

    Purpose: To investigate the dosimetric differences among three-dimensional conformal radiotherapy (3D-CRT), dynamic conformal arc therapy (DCAT), and intensity-modulated radiotherapy (IMRT) for brain tumor treatment. Methods and Materials: Fifteen patients treated with Novalis were selected. We performed 3D-CRT, DCAT, and IMRT plans for all patients. The margin for the planning target volume (PTV) was 1 mm, and the specific prescription dose was 90% for all plans. The target coverage at the prescription dose, conformity index (CI), and heterogeneity index were analyzed for all plans. Results: For small tumors (PTV ≤2 cm 3 ), the three dosimetric parameters had approximate values for both 3D-CRT and DCAT plans. The CI for the IMRT plans was high. For medium tumors (PTV >2 to ≤100 cm 3 ), the three plans were competitive with each other. The IMRT plans had a greater CI, better target coverage at the prescription dose, and a better heterogeneity index. For large tumors (PTV >100 cm 3 ), the IMRT plan had good target coverage at the prescription dose and heterogeneity index and approximate CI values as those in the 3D-CRT and DCAT plans. Conclusion: The results of our study have shown that DCAT is suitable for most cases in the treatment of brain tumors. For a small target, 3D-CRT is useful, and IMRT is not recommended. For larger tumors, IMRT is superior to 3D-CRT and very competitive in sparing critical structures, especially for big tumors

  9. 3-D conformal treatment of prostate cancer to 74 Gy vs. high-dose-rate brachytherapy boost: A cross-sectional quality-of-life survey

    Energy Technology Data Exchange (ETDEWEB)

    Vordermark, Dirk [Univ. of Wuerzburg (DE). Dept. of Radiation Oncology] (and others)

    2006-09-15

    The effects of two modalities of dose-escalated radiotherapy on health-related quality of life (HRQOL) were compared. Forty-one consecutive patients were treated with a 3-D conformal (3-DC) boost to 74 Gy, and 43 with high-dose rate (HDR) brachytherapy boost (2x9 Gy), following 3-D conformal treatment to 46 Gy. Median age was 70 years in both groups, median initial PSA was 7.9 {mu}g/l in 3-DC boost patients and 8.1 {mu}g/l in HDR boost patients. Stage was 7 in 52% and 47%, respectively. HRQOL was assessed cross-sectionally using EORTC QLQ-C30 and organ-specific PR25 modules 3-32 (median 19) and 4-25 (median 14) months after treatment, respectively. Questionnaires were completed by 93% and 97% of patients, respectively. Diarrhea and insomnia scores were significantly increased in both groups. In the PR25 module, scores of 3-DC boost and HDR boost patients for urinary, bowel and treatment-related symptoms were similar. Among responders, 34% of 3-DC boost patients and 86% of HDR boost patients had severe erectile problems. Dose escalation in prostate cancer by either 3-DC boost to 74 Gy or HDR brachytherapy boost appears to result in similar HRQOL profiles.

  10. Potential clinical efficacy of intensity-modulated conformal therapy

    International Nuclear Information System (INIS)

    Meeks, Sanford L.; Buatti, John M.; Bova, Francis J.; Friedman, William A.; Mendenhall, William M.; Zlotecki, Robert A.

    1998-01-01

    Purpose: The purpose of this study was to examine the potential benefit of using intensity-modulated conformal therapy for a variety of lesions currently treated with stereotactic radiosurgery or conventional radiotherapy. Methods and Materials: Intensity-modulated conformal treatment plans were generated for small intracranial lesions, as well as head and neck, lung, breast, and prostate cases, using the Peacock Plan[reg] treatment-planning system (Nomos Corporation). For small intracranial lesions, intensity-modulated conformal treatment plans were compared with stereotactic radiosurgery treatment plans generated for patient treatment at the University of Florida Shands Cancer Center. For other sites (head and neck, lung, breast, and prostate), plans generated using the Peacock Plan[reg] were compared with conventional treatment plans, as well as beam's-eye-view conformal treatment plans. Plan comparisons were accomplished through conventional qualitative review of two-dimensional (2D) dose distributions in conjunction with quantitative techniques, such as dose-volume histograms, dosimetric statistics, normal tissue complication probabilities, tumor control probabilities, and objective numerical scoring. Results: For small intracranial lesions, there is little difference between intensity-modulated conformal treatment planning and radiosurgery treatment planning in the conformation of high isodose lines with the target volume. However, stereotactic treatment planning provides a steeper dose gradient outside the target volume and, hence, a lower normal tissue toxicity index. For extracranial sites, objective numerical scores for beam's-eye-view and intensity-modulated conformal planning techniques are superior to scores for conventional treatment plans. The beam's-eye-view planning technique prevents geographic target misses and better excludes healthy tissues from the treatment portal. Compared with scores for the beam's-eye-view planning technique, scores for

  11. Conformity index: A review

    International Nuclear Information System (INIS)

    Feuvret, Loic; Noel, Georges; Mazeron, Jean-Jacques; Bey, Pierre

    2006-01-01

    We present a critical analysis of the conformity indices described in the literature and an evaluation of their field of application. Three-dimensional conformal radiotherapy, with or without intensity modulation, is based on medical imaging techniques, three-dimensional dosimetry software, compression accessories, and verification procedures. It consists of delineating target volumes and critical healthy tissues to select the best combination of beams. This approach allows better adaptation of the isodose to the tumor volume, while limiting irradiation of healthy tissues. Tools must be developed to evaluate the quality of proposed treatment plans. Dosimetry software provides the dose distribution in each CT section and dose-volume histograms without really indicating the degree of conformity. The conformity index is a complementary tool that attributes a score to a treatment plan or that can compare several treatment plans for the same patient. The future of conformal index in everyday practice therefore remains unclear

  12. Optimal 3-D conformal treatment planning of posterior lateral supratentorial tumors

    International Nuclear Information System (INIS)

    Gius, David; Klein, Eric; Oehmke, Fred

    1995-01-01

    Purpose/Objective: The ability to treat the brain to greater doses is limited by normal brain tissue tolerance. With the use of 3-dimensional treatment planning dose escalation will result in increased target dose while sparing normal tissue. Treatment of the supratentorial region of the brain presents several unique difficulties due to the changing contour of the calvarium, which are especially noticeable with treatment to the posterior lateral quadrant. The use of a single wedge beam is sub-optimal and a more appropriate solution would employ a two tier wedge arrangement to better conform the isodoses around the target volume. In the past it has only been possible to use a single wedge during treatment with a single port, however, the dynamic wedge presents the opportunity to employ a two tier wedge system by simultaneously using conventional and dynamic wedging. Methods and Materials: An anthropomorphic phantom with a lesion located in the posterior lateral aspect of the brain where the external surface slopes at a maximum was configured. CT generated contours outlined the external surface, normal anatomy, gross tumor, and target volumes. We used the beam's-eye-view projection from the 3D planning system to derive the conformal beams. A standard opposed lateral and posterior oblique wedge pair beam arrangements, were compared to a three field technique (PA, lateral, and vertex) which used both a single wedge arrangement and a two-tier wedge plan. Treatment plans were evaluated by calculating isodose distribution, DVH, TCP, and NTCP. Each beam arrangement was used to treat our phantom with film placed in between the phantom layers at the tumor levels to confirm the accuracy of the 3-D system calculations. Results: The three field, two-tier wedge technique isodose distribution was significantly superior when compared to the standard 2-D plans, and a moderate improvement over the three field, single wedge technique in terms of conforming dose to the tumor and

  13. Chronic rectal bleeding after high-dose conformal treatment of prostate cancer warrants modification of existing morbidity scales

    International Nuclear Information System (INIS)

    Hanlon, Alexandra L.; Schultheiss, Timothy E.; Hunt, Margie A.; Movsas, Benjamin; Peter, Ruth S.; Hanks, Gerald E.

    1997-01-01

    coagulations. The median duration of bleeding for those patients requiring multiple procedures was 7 months (range 3-33) and the median latency was 22 months (range 9-40). The 5-year actuarial rate of Grade (3(4)) complications by each scale are: RTOG 0.7%, LENT 2%, and FC-LENT 6%. The rate of chronic rectal bleeding increases with increasing dose and is low in patients treated with conventional techniques owing to lower doses. Conclusion: Chronic rectal bleeding requiring any blood transfusion(s) or multiple coagulation procedures is our most frequently observed complication. This complication appears late in follow-up and is present for a long duration. We believe this justifies the inclusion of chronic rectal bleeding requiring multiple coagulation procedures as a Grade 3 event in future morbidity scales. Our data illustrate that published Grade (3(4)) morbidity rates are highly dependent on the morbidity scale selected, as our data show 0.7% RTOG, 2% LENT, and 6% FC-LENT. Obviously, a uniform scale is required that includes the newly recognized serious late effects associated with the conformal treatment of prostate cancer

  14. Multilayer conformal applicator for microwave heating and brachytherapy treatment of superficial tissue disease.

    Science.gov (United States)

    Juang, T; Stauffer, P R; Neuman, D G; Schlorff, J L

    2006-11-01

    The purpose of this study was to construct and perform preliminary functionality evaluations of a multilayer conformal applicator with provisions for thermal monitoring, tight conformity and simultaneous microwave heating and brachytherapy treatment of large-area contoured surfaces. The multilayer conformal applicator consists of thermal monitoring catheters for fibre-optic monitoring of skin temperatures, a waterbolus, a PCB microwave antenna array, a dielectric spacer for brachytherapy considerations, brachytherapy catheters for delivering HDR radiation and an inflatable air bladder for improving conformity to contoured surfaces. The applicator also includes an elastic attachment structure to hold the applicator securely in place on the patient. The conformity of the applicator to irregular surfaces was evaluated through CT imaging of the applicator fitted onto a life-sized human torso phantom. The fluid flow dynamics of the waterbolus, which impact the effectiveness of temperature control, were evaluated with thermometry during a 19 degrees C step change temperature of the circulating water. CT imaging showed improved conformity to the torso phantom surface following the application of gentle inward pressure from inflating the outer air bladder. Only a small number of 1-5 mm sized air gaps separated the conformal applicator and tissue surface. Thermometry testing of the bolus fluid flow dynamics demonstrated temperature uniformity within +/-0.82 degrees C across a 19 x 34 x 0.6 cm area bolus and +/-0.85 degrees C across a large 42 x 32 x 0.6 cm area bolus. CT scans of the applicator confirmed that the applicator conforms well to complex body contours and should maintain good conformity and positional stability even when worn on a mobile patient. Thermometry testing of two different waterbolus geometries demonstrated that uniform circulation and temperature control can be maintained throughout large, complex bolus shapes.

  15. Replacement between conformity and counter-conformity in consumption decisions.

    Science.gov (United States)

    Chou, Ting-Jui; Chang, En-Chung; Dai, Qi; Wong, Veronica

    2013-02-01

    This study assessed, in a Chinese context, how self-esteem interacts with perceived similarity and uniqueness to yield cognitive dissonance, and whether the dissonance leads to self-reported conformity or counter-conformity behavior. Participants were 408 respondents from 4 major Chinese cities (M age = 33.0 yr., SD = 4.3; 48% men). Self-perceptions of uniqueness, similarity, cognitive dissonance, self-esteem and need to behave in conformity or counter-conformity were measured. A theoretical model was assessed in four situations, relating the ratings of self-esteem and perceived similarity/uniqueness to the way other people at a wedding were dressed, and the resultant cognitive dissonance and conformity/ counter-conformity behavior. Regardless of high or low self-esteem, all participants reported cognitive dissonance when they were told that they were dressed extremely similarly to or extremely differently from the other people attending the wedding. However, the conforming/counter-conforming strategies used by participants to resolve the cognitive dissonance differed. When encountering dissonance induced by the perceived extreme uniqueness of dress, participants with low self-esteem tended to say they would dress next time so as to conform with the way others were dressed, while those with high self-esteem indicated they would continue their counter-conformity in attire. When encountering dissonance induced by the perceived extreme similarity to others, both those with high and low self-esteem tended to say they would dress in an unorthodox manner to surprise other people in the future.

  16. Acute toxicity in pelvic radiotherapy; a randomised trial of conformal versus conventional treatment

    International Nuclear Information System (INIS)

    Tait, Diana M.; Nahum, Alan E.; Meyer, Lesley C.; Law, Matthew; Dearnaley, David P.; Horwich, Alan; Mayles, W. Philip; Yarnold, John R.

    1997-01-01

    Background: A prospective, randomized clinical trial to assess the effect of reducing the volume of irradiated normal tissue on acute reactions in pelvic radiotherapy accrued 266 evaluable patients between 1988 and 1993. Purpose: This is the definitive analysis to assess the differences between the conformal and conventional arms of the trial. Materials and methods: In both arms, patients were treated with 6 MV X-rays using a 3-field technique (in all but 5 cases) consisting of an anterior and two wedged lateral or posterior oblique fields; in the conventional arm, rectangular fields were employed, whereas in the conformal arm, the fields were shaped with customized blocks drawn according to the beam's-eye-view of the target volume. The most common dosage was 65 Gy in 2-Gy fractions 5 times a week, although a subgroup (of ca. bladder patients) were treated with 30-36 Gy in once-a-week 6 Gy fractions. Each patient completed a comprehensive acute toxicity scoring questionnaire concentrating on bowel and bladder problems, tiredness and nausea, before the start of treatment, weekly during and for 3 weeks after the end of treatment and then monthly for a further 2 months. Compliance was excellent. Results: There were no differences between the patients in the two arms with respect to age, gender, tumour type (52% prostate, 41% bladder, 5% rectum, 2% other) fractionation/dosage, anterior field size, weight, or baseline symptoms. Substantial differences in normal-tissue volumes (rectum, bladder, etc.) were achieved: median high-dose volume (HDV) of 689 cm 3 for the conformal technique versus 792 cm 3 for the conventional. A clear pattern of an increase in symptoms during RT, followed by a decrease after RT, was observed for the patient group as a whole. However, a very extensive analysis has not revealed any (statistically) significant differences between the two arms in level of symptoms, nor in medication prescribed. The disparity between our findings and those of other

  17. High precision conformal radiotherapy employing conservative margins in childhood benign and low-grade brain tumours

    International Nuclear Information System (INIS)

    Jalali, Rakesh; Budrukkar, Ashwini; Sarin, Rajiv; Sharma, Dayananda S.

    2005-01-01

    Background and purpose: To report local control and follow up outcome data of high precision conformal radiotherapy in childhood brain tumours. Materials and methods: Between December 1999 and December 2002, 26 children (17 boys and 9 girls, median age 11.5 years) with incompletely excised or recurrent benign and low-grade brain tumours [13 craniopharyngiomas, 11 low-grade gliomas (LGG) and 2 others] were treated with three-dimensional (3D) conformal radiotherapy (CRT) (12 patients) and stereotactic conformal radiotherapy (SCRT) (14 patients). Gross tumour volume (GTV) included neuro-imaging based visible tumour and/or resected tumour bed. Clinical target volume (CTV) consisted of GTV + 5 mm margin and planning target volume (PTV) consisted of additional 5 mm margin for CRT and 2 mm for SCRT. Treatment was delivered with 3-9 conformal fixed fields to a median dose of 54 Gy/30 fractions. Results: The actuarial 2 and 3 year disease free and overall survival was 96 and 100%, respectively (median follow up: 25 months, range 12-47 months). Radiological follow up available in 25 patients revealed complete response in 1, partial regression in 10, stable disease in 13 and progression in 1 patient (within the CTV). One patient with craniopharyngioma on a routine imaging revealed a mild asymptomatic cyst enlargement, which resolved with conservative management. A patient with chiasmatic glioma developed cystic degeneration and hydrocephalus 9 months after SCRT requiring cyst drainage and placement of a ventriculoperitoneal shunt. Conclusion: High-precision conformal techniques delivering irradiation to a computer generated target volume employing 7-10 mm 3D margins beyond the visible tumour and/or resected tumour bed appear to be safe in children with incompletely resected or recurrent benign and low-grade brain tumours, based on these data

  18. Predicting treatment related imaging changes (TRICs) after radiosurgery for brain metastases using treatment dose and conformality metrics.

    Science.gov (United States)

    Taylor, B Frazier; Knisely, Jonathan P; Qian, Jack M; Yu, James B; Chiang, Veronica L

    2016-01-01

    Treatment-related imaging changes (TRICs) after stereotactic radiosurgery (SRS) involves the benign transient enlargement of radiographic lesions after treatment. Identifying the radiation dose volumes and conformality metrics associated with TRICs for different post-treatment periods would be helpful and improve clinical decision making. 367 metastases in 113 patients were treated using Gamma Knife SRS between 1/1/2007-12/31/2009. Each metastasis was measured at each imaging follow-up to detect TRICs (defined as ≥ 20% increase in volume). Fluctuations in small volume lesions (less than 108 mm 3 ) were ignored given widely variable conformity indices (CI) for small volumes. The Karolinska Adverse Radiation Effect (KARE) factor, Paddick's CI, Shaw's CI, tumor volume (TV), 10 Gy (V10) and 12 Gy (V12) volumes, and prescription isodose volume (PIV) were calculated. From 0-6 months, all measures correlated with the incidence of TRICs (p<.001), except KARE, which was inversely correlated. During the 6-12 month period all measures except KARE were still correlated. Beyond 12 months, no correlation was found between any of the measures and the development of TRICs. All metrics except KARE were associated with TRICs from 0-12 months only. Additional patient and treatment factors may become dominant at greater times after SRS.

  19. Conformal Coating of Cobalt-Nickel Layered Double Hydroxides Nanoflakes on Carbon Fibers for High-performance Electrochemical Energy Storage Supercapacitor Devices

    KAUST Repository

    Warsi, Muhammad Farooq

    2014-07-01

    High specific capacitance coupled with the ease of large scale production is two desirable characteristics of a potential pseudo-supercapacitor material. In the current study, the uniform and conformal coating of nickel-cobalt layered double hydroxides (CoNi0.5LDH,) nanoflakes on fibrous carbon (FC) cloth has been achieved through cost-effective and scalable chemical precipitation method, followed by a simple heat treatment step. The conformally coated CoNi0.5LDH/FC electrode showed 1.5 times greater specific capacitance compared to the electrodes prepared by conventional non-conformal (drop casting) method of depositing CoNi0.5LDH powder on the carbon microfibers (1938 Fg-1 vs 1292 Fg-1). Further comparison of conformally and non-conformally coated CoNi0.5LDH electrodes showed the rate capability of 79%: 43% capacity retention at 50 Ag-1 and cycling stability 4.6%: 27.9% loss after 3000 cycles respectively. The superior performance of the conformally coated CoNi0.5LDH is mainly due to the reduced internal resistance and fast ionic mobility between electrodes as compared to non-conformally coated electrodes which is evidenced by EIS and CV studies. © 2014 Elsevier Ltd.

  20. Conformal Coating of Cobalt-Nickel Layered Double Hydroxides Nanoflakes on Carbon Fibers for High-performance Electrochemical Energy Storage Supercapacitor Devices

    KAUST Repository

    Warsi, Muhammad Farooq; Shakir, Imran; Shahid, Muhammad; Sarfraz, Mansoor M.; Nadeem, Muhammad Tahir; Gilani, Zaheer Abbas

    2014-01-01

    High specific capacitance coupled with the ease of large scale production is two desirable characteristics of a potential pseudo-supercapacitor material. In the current study, the uniform and conformal coating of nickel-cobalt layered double hydroxides (CoNi0.5LDH,) nanoflakes on fibrous carbon (FC) cloth has been achieved through cost-effective and scalable chemical precipitation method, followed by a simple heat treatment step. The conformally coated CoNi0.5LDH/FC electrode showed 1.5 times greater specific capacitance compared to the electrodes prepared by conventional non-conformal (drop casting) method of depositing CoNi0.5LDH powder on the carbon microfibers (1938 Fg-1 vs 1292 Fg-1). Further comparison of conformally and non-conformally coated CoNi0.5LDH electrodes showed the rate capability of 79%: 43% capacity retention at 50 Ag-1 and cycling stability 4.6%: 27.9% loss after 3000 cycles respectively. The superior performance of the conformally coated CoNi0.5LDH is mainly due to the reduced internal resistance and fast ionic mobility between electrodes as compared to non-conformally coated electrodes which is evidenced by EIS and CV studies. © 2014 Elsevier Ltd.

  1. Postoperative Chemotherapy Followed by Conformal Concomitant Chemoradiotherapy in High-Risk Gastric Cancer

    International Nuclear Information System (INIS)

    Quero, Laurent; Bouchbika, Zineb; Kouto, Honorine; Baruch-Hennequin, Valerie; Gornet, Jean-Marc; Munoz, Nicolas; Cojean-Zelek, Isabelle; Houdart, Remi; Panis, Yves; Valleur, Patrice; Aparicio, Thomas; Maylin, Claude; Hennequin, Christophe

    2012-01-01

    Purpose: To analyze the efficacy, toxicity, and pattern of relapse after adjuvant cisplatin-based chemotherapy followed by three-dimensional irradiation and concomitant LV5FU2 chemotherapy (high-dose leucovorin and 5-fluorouracil bolus plus continuous infusion) in the treatment of completely resected high-risk gastric cancer. Methods and Materials: This was a retrospective analysis of 52 patients with high-risk gastric cancer initially treated by total/partial gastrectomy and lymphadenectomy between January 2002 and June 2007. Median age was 54 years (range, 36–75 years). Postoperative treatment consisted of 5-fluorouracil and cisplatin chemotherapy. Adjuvant chemotherapy was followed by three-dimensional conformal radiotherapy in the tumor bed and regional lymph nodes at 4500 cGy/25 fractions in association with concomitant chemotherapy. Concomitant chemotherapy consisted of a 2-h infusion of leucovorin (200 mg/m²) followed by a bolus of 5-fluorouracil (400 mg/m²) and then a 44-h continuous infusion of 5-fluorouracil (2400–3600 mg/m²) given every 14 days, for three cycles (LV5FU2 protocol). Results: Five-year overall and disease-free survival were 50% and 48%, respectively. Distant metastases and peritoneal spread were the most frequent sites of relapse (37% each). After multivariate analysis, only pathologic nodal status was significantly associated with disease-free and overall survival. Acute toxicities were essentially gastrointestinal and hematologic. One myocardial infarction and one pulmonary embolism were also reported. Eighteen patients had a radiotherapy program interruption because of acute toxicity. All patients but 2 have completed radiotherapy. Conclusion: Postoperative cisplatin-based chemotherapy followed by conformal radiotherapy in association with concurrent 5-fluorouracil seemed to be feasible and resulted in successful locoregional control.

  2. Trickle-Down Preferences: Preferential Conformity to High Status Peers in Fashion Choices

    Science.gov (United States)

    Galak, Jeff; Gray, Kurt; Elbert, Igor; Strohminger, Nina

    2016-01-01

    How much do our choices represent stable inner preferences versus social conformity? We examine conformity and consistency in sartorial choices surrounding a common life event of new norm exposure: relocation. A large-scale dataset of individual purchases of women’s shoes (16,236 transactions) across five years and 2,007 women reveals a balance of conformity and consistency, moderated by changes in location socioeconomic status. Women conform to new local norms (i.e., average heel size) when moving to relatively higher status locations, but mostly ignore new local norms when moving to relatively lower status locations. In short, at periods of transition, it is the fashion norms of the rich that trickle down to consumers. These analyses provide the first naturalistic large-scale demonstration of the tension between psychological conformity and consistency, with real decisions in a highly visible context. PMID:27144595

  3. Trickle-Down Preferences: Preferential Conformity to High Status Peers in Fashion Choices.

    Directory of Open Access Journals (Sweden)

    Jeff Galak

    Full Text Available How much do our choices represent stable inner preferences versus social conformity? We examine conformity and consistency in sartorial choices surrounding a common life event of new norm exposure: relocation. A large-scale dataset of individual purchases of women's shoes (16,236 transactions across five years and 2,007 women reveals a balance of conformity and consistency, moderated by changes in location socioeconomic status. Women conform to new local norms (i.e., average heel size when moving to relatively higher status locations, but mostly ignore new local norms when moving to relatively lower status locations. In short, at periods of transition, it is the fashion norms of the rich that trickle down to consumers. These analyses provide the first naturalistic large-scale demonstration of the tension between psychological conformity and consistency, with real decisions in a highly visible context.

  4. Trickle-Down Preferences: Preferential Conformity to High Status Peers in Fashion Choices.

    Science.gov (United States)

    Galak, Jeff; Gray, Kurt; Elbert, Igor; Strohminger, Nina

    2016-01-01

    How much do our choices represent stable inner preferences versus social conformity? We examine conformity and consistency in sartorial choices surrounding a common life event of new norm exposure: relocation. A large-scale dataset of individual purchases of women's shoes (16,236 transactions) across five years and 2,007 women reveals a balance of conformity and consistency, moderated by changes in location socioeconomic status. Women conform to new local norms (i.e., average heel size) when moving to relatively higher status locations, but mostly ignore new local norms when moving to relatively lower status locations. In short, at periods of transition, it is the fashion norms of the rich that trickle down to consumers. These analyses provide the first naturalistic large-scale demonstration of the tension between psychological conformity and consistency, with real decisions in a highly visible context.

  5. Dose conformation to the spine during palliative treatments using dynamic wedges

    Energy Technology Data Exchange (ETDEWEB)

    Ormsby, Matthew A., E-mail: Matthew.Ormsby@usoncology.com [West Texas Cancer Center at Medical Center Hospital, Odessa, TX (United States); Herndon, R. Craig; Kaczor, Joseph G. [West Texas Cancer Center at Medical Center Hospital, Odessa, TX (United States)

    2013-07-01

    Radiation therapy is commonly used to alleviate pain associated with metastatic disease of the spine. Often, isodose lines are manipulated using dynamic or physical wedges to encompass the section of spine needing treatment while minimizing dose to normal tissue. We will compare 2 methods used to treat the entire thoracic spine. The first method treats the thoracic spine with a single, nonwedged posterior-anterior (PA) field. Dose is prescribed to include the entire spine. Isodose lines tightly conform to the top and bottom vertebrae, but vertebrae between these 2 received more than enough coverage. The second method uses a combination of wedges to create an isodose line that mimics the curvature of the thoracic spine. This “C”-shaped curvature is created by overlapping 2 fields with opposing dynamic wedges. Machine constraints limit the treatment length and therefore 2 isocenters are used. Each of the 2 PA fields contributes a portion of the total daily dose. This technique creates a “C”-shaped isodose line that tightly conforms to the thoracic spine, minimizing normal tissue dose. Spinal cord maximum dose is reduced, as well as mean dose to the liver, esophagus, and heart.

  6. Bolus electron conformal therapy for the treatment of recurrent inflammatory breast cancer: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Michelle M., E-mail: mmkim@mdanderson.org [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Kudchadker, Rajat J.; Kanke, James E.; Zhang, Sean; Perkins, George H. [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States)

    2012-07-01

    The treatment of locoregionally recurrent breast cancer in patients who have previously undergone radiation therapy is challenging. Special techniques are often required that both eradicate the disease and minimize the risks of retreatment. We report the case of a patient with an early-stage left breast cancer who developed inflammatory-type recurrence requiring re-irradiation of the chest wall using bolus electron conformal therapy with image-guided treatment delivery. The patient was a 51-year-old woman who had undergone lumpectomy, axillary lymph node dissection, and adjuvant whole-breast radiation therapy for a stage I left breast cancer in June 1998. In March 2009, she presented at our institution with biopsy-proven recurrent inflammatory carcinoma and was aggressively treated with multi-agent chemotherapy followed by mastectomy that left a positive surgical margin. Given the patient's prior irradiation and irregular chest wall anatomy, bolus electron conformal therapy was used to treat her chest wall and draining lymphatics while sparing the underlying soft tissue. The patient still had no evidence of disease 21 months after treatment. Our results indicate that bolus electron conformal therapy is an accessible, effective radiation treatment approach for recurrent breast cancer in patients with irregular chest wall anatomy as a result of surgery. This approach may complement standard techniques used to reduce locoregional recurrence in the postmastectomy setting.

  7. Effect of Concurrent High-Dose Cisplatin Chemotherapy and Conformal Radiotherapy on Cervical Esophageal Cancer Survival

    International Nuclear Information System (INIS)

    Huang Shaohui; Lockwood, Gina; Brierley, James; Cummings, Bernard; Kim, John; Wong, Rebecca; Bayley, Andrew; Ringash, Jolie

    2008-01-01

    Purpose: To determine whether a change in treatment policy to conformal, elective nodal radiotherapy and concurrent high-dose cisplatin improved survival for cervical esophageal cancer patients. Methods and Materials: All cervical esophageal cancer patients treated between 1997 and 2005 were restaged (1983 American Joint Committee on Cancer criteria). Patients treated before 2001 (previous cohort [PC]) were compared with those treated from 2001 onward (recent cohort [RC]). The PC institutional chemoradiotherapy protocol was 54 Gy in 20 fractions within 4 weeks, with 5-fluorouracil (1,000 mg/m 2 ) on Days 1-4 and either mitomycin C (10 mg/m 2 ) or cisplatin (75 mg/m 2 ) on Day 1. The RC institutional chemoradiotherapy protocol was conformal radiotherapy, 70 Gy in 35 fractions within 7 weeks, to the primary tumor and elective nodes, with high-dose cisplatin (100 mg/m 2 ) on Days 1, 22, and 43. Results: The median follow-up was 3.1 years (PC, 8.1 and RC, 2.3). Of 71 patients (25 women and 46 men), 21 of 29 in the PC and 29 of 42 in the RC were treated curatively (curative subgroup, n = 50). Between the two groups, no differences in overall survival or locoregional relapse-free survival were seen. The overall survival rate at 2 and 5 years was 35% (range, 24-47%) and 21% (range, 12-32%) in the whole group and 46% (range 32-60%) and 28% (range, 15-42%) in the curative group, respectively. In the curative group, no statistically significant prognostic factors were found. Trends toward better locoregional relapse-free survival were seen in women (2-year rate, 73% vs. for men, 36%; p = 0.08) and in patients aged >64 years (2-year rate, 68% vs. age ≤64 years, 34%; p = 0.10). Conclusion: No survival improvement could be demonstrated after changing the treatment policy to high-dose cisplatin-based, conventionally fractionated conformal chemoradiotherapy. Female gender and older age might predict for better outcomes

  8. Conformity index for brain cancer patients

    International Nuclear Information System (INIS)

    Petkovska, Sonja; Tolevska, Cveta; Kraleva, Slavica; Petreska, Elena

    2010-01-01

    The purpose of this study is to present the level of conformity achieved by using 3D conformal radiotherapy for brain cancer patients. Conformity index is a helpful quantitative tool for assessing (evaluating) the quality of a treatment plan. Treatment plans made for ninety patients with brain tumor are worked on this paper. The patients are in supine position and immobilized with thermoplastic masks for the head. Computed tomography data sets with 5 mm scan thickness are used to create a 3D image. All structures of interest are contoured. In order to obtain an optimal dose distribution, treatment fields are fit around target volume with set-up margins of 7mm in each direction. The conformity index values are between 1.21 and 2.04. Value of 1.8 is exceeded in eighteen cases; nine of them are bigger than 1.9 and only three of them are above 2. The target volume for each of these extreme CI values is ideal covered (between 95% and 105% of the prescribed dose). The most acceptable conformity index value in this paper belongs to the plan with the lowest minimal dose (84.7%). It can be concluded that conformity index is necessary but not sufficient factor for assessing radiation treatment plan conformity. To be able to estimate the acceptability of some treatment plan in daily practice, additional information as minimal, maximal and mean dose into target volume, as well as health tissues coverage must be taken into account.(Author)

  9. Rectal bleeding after conformal 3D treatment of prostate cancer: time to occurrence, response to treatment and duration of morbidity

    International Nuclear Information System (INIS)

    Teshina, Teruki; Hanks, Gerald E.; Peters, Ruth S.; Hanlon, Alexandra L.; Schultheiss, Timothy E.

    1996-01-01

    Purpose: Late rectal bleeding is the most common sequelae of high dose 3D conformal treatment (3DCRT) for prostate cancer and limits attempts to improve local control by dose escalation. The clinical course of this complication is reported including time to onset, response to treatment, duration of morbidity and risk factor analysis by multivariate analysis. Materials and Methods: From March, 1989 to June 1996, 670 patients with prostate cancer were treated with 3DCRT. Eighty-nine patients developed grade 2 or 3 complications due to rectal bleeding and are analyzed (Grade 2 LENT scale, Grade 3 Fox Chase modification of LENT including >2 coagulations as Grade 3). They are compared to 581 patients without Grade 2,3 morbidity in multivariate analysis. Time to development, response to initial and retreatment and duration of morbidity are tabulated. Results: The median time to occurrence is not significantly different (p=.09) for Grade 2 (13 mo. range 4-41 mo.) compared to Grade 3 (18 mo. range 4-40 mo.). The corresponding median duration of symptoms >Grade 1 were significantly different (p=.0001) being 1 month (range 1-<12) versus 10 months (1-34) respectively. The response to treatment and retreatment is shown in Table 1. For Grade 2 complications medication or coagulation was highly effective as initial or retreatment resolving 66 of 73 patients. For Grade 3 a few responded to only transfusion and with multiple coagulations and medication (12(16)) patients improved to ≤ Grade 1. Multivariate analysis demonstrates that dose is the only significant factor associated with Grade 2 (LENT) (p=.01) or Grade 3 (FC-LENT) (p=.01) complication. Lack of response to treatment was associated with hypertension on univariate analysis only. Of 7 non-responders to treatment of Grade 2 bleeding, 3 have died of intercurrent disease at 10, 19 and 26 months while 4 are alive with continuing Grade 2 bleeding at 26, 34, 41 and 45 months after onset. Of 4 non-responders to treatment of

  10. Rectal bleeding after conformal 3D treatment of prostate cancer: Time to occurrence, response to treatment and duration of morbidity

    International Nuclear Information System (INIS)

    Teshima, Teruki; Hanks, Gerald E.; Hanlon, Alexandra L.; Peter, Ruth S.; Schultheiss, Timothy E.

    1997-01-01

    Purpose: Rectal bleeding is the most common late sequelae of high-dose 3D conformal treatment (3DCRT) for prostate cancer and may limit attempts to improve local control by dose escalation. The clinical course of this complication is reported including time to onset, response to treatment, duration of morbidity, and multivariate analysis for predictors. Methods and Materials: From March 1989 to June 1995, 670 patients with prostate cancer were treated with 3DCRT at Fox Chase Cancer Center. Eighty-nine patients developed Grade 2 or Grade 3 complications due to rectal bleeding and are analyzed. Multivariate analysis results for predictors of Grade 2 and 3 rectal bleeding are reported as well as time to development, response to initial and retreatment, and duration of morbidity. Results: The median time to occurrence is not significantly different (p = 0.09) for Grade 2 (13 months, range 4-41 months) compared to Grade 3 rectal bleeding (18 months, range 4-40 months), while the corresponding median duration of symptoms was significantly different (p < 0.0001) being 1 month (range 1-12) vs. 10 months (1-34) for Grade 2 and Grade 3 bleeding, respectively. For Grade 2 bleeding, medication or coagulation was highly effective as initial or retreatment resolving 66 of 73 patients. For Grade 3 bleeding, three patients responded without medication following blood transfusion only, while with multiple coagulations and medication 12 of 16 patients improved to ≤ Grade 1. Multivariate analysis demonstrates that dose is the only significant factor associated with Grade 2 (p = 0.01) or Grade 3 (p = 0.01) rectal bleeding. Of seven nonresponders to treatment for Grade 2 bleeding, three have died of intercurrent disease at 10, 19, and 26 months, while four are alive with continuing Grade 2 bleeding at 12, 14, 15, and 30 months after onset. The four nonresponders to treatment for Grade 3 bleeding continue to bleed 1, 9, 32, and 35 months after the third coagulation despite continuing

  11. SU-E-T-538: Lung SBRT Dosimetric Comparison of 3D Conformal and RapidArc Planning

    International Nuclear Information System (INIS)

    Jiang, R; Zhan, L; Osei, E

    2015-01-01

    Purpose: Dose distributions of RapidArc Plan can be quite different from standard 3D conformal radiation therapy. SBRT plans can be optimized with high conformity or mimic the 3D conformal treatment planning with very high dose in the center of the tumor. This study quantifies the dosimetric differences among 3D conformal plan; flattened beam and FFF beam RapidArc Plans for lung SBRT. Methods: Five lung cancer patients treated with 3D non-coplanar SBRT were randomly selected. All the patients were CT scanned with 4DCT to determine the internal target volume. Abdominal compression was applied to minimize respiratory motion for SBRT patients. The prescription dose was 48 Gy in 4 fractions. The PTV coverage was optimized by two groups of objective function: one with high conformity, another mimicking 3D conformal dose distribution with high dose in the center of PTV. Optimization constraints were set to meet the criteria of the RTOG-0915 protocol. All VMAT plans were optimized with the RapidArc technique using four full arcs in Eclipse treatment planning system. The RapidArc SBRT plans with flattened 6MV beam and 6MV FFF beam were generated and dosimetric results were compared with the previous treated 3D non-coplanar plans. Results: All the RapidArc plans with flattened beam and FFF beam had similar results for the PTV and OARs. For the high conformity optimization group, The DVH of PTV exhibited a steep dose fall-off outside the PTV compared to the 3D non-coplanar plan. However, for the group mimicking the 3D conformal target dose distribution, although the PTV is very similar to the 3D conformal plan, the ITV coverage is better than 3D conformal plan. Conclusion: Due to excellent clinical experiences of 3D conformal SBRT treatment, the Rapid Arc optimization mimicking 3D conformal planning may be suggested for clinical use

  12. Structural investigation of ribonuclease A conformational preferences using high pressure protein crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Kurpiewska, Katarzyna, E-mail: kurpiews@chemia.uj.edu.pl [Jagiellonian University, Faculty of Chemistry, Department of Crystal Chemistry and Crystal Physics, Protein Crystallography Group, Ingardena 3, 30-060 Kraków (Poland); Dziubek, Kamil; Katrusiak, Andrzej [Adam Mickiewicz University, Faculty of Chemistry, Department of Materials Chemistry, Umultowska 89b, 61-61 Poznań (Poland); Font, Josep [School of Medical Science, University of Sydney, NSW 2006 (Australia); Ribò, Marc; Vilanova, Maria [Universitat de Girona, Laboratorid’Enginyeria de Proteïnes, Departament de Biologia, Facultat de Ciències, Campus de Montilivi, 17071 Girona (Spain); Lewiński, Krzysztof [Jagiellonian University, Faculty of Chemistry, Department of Crystal Chemistry and Crystal Physics, Protein Crystallography Group, Ingardena 3, 30-060 Kraków (Poland)

    2016-04-01

    Highlights: • A unique crystallographic studies of wild-type and mutated form of the same protein under high pressure. • Compressibility of RNase A molecule is significantly affected by a single amino acid substitution. • High pressure protein crystallography helps understanding protein flexibility and identify conformational substrates. - Abstract: Hydrostatic pressure in range 0.1–1.5 GPa is used to modify biological system behaviour mostly in biophysical studies of proteins in solution. Due to specific influence on the system equilibrium high pressure can act as a filter that enables to identify and investigate higher energy protein conformers. The idea of the presented experiments is to examine the behaviour of RNase A molecule under high pressure before and after introduction of destabilizing mutation. For the first time crystal structures of wild-type bovine pancreatic ribonuclease A and its markedly less stable variant modified at position Ile106 were determined at different pressures. X-ray diffraction experiments at high pressure showed that the secondary structure of RNase A is well preserved even beyond 0.67 GPa at room temperature. Detailed structural analysis of ribonuclease A conformation observed under high pressure revealed that pressure influences hydrogen bonds pattern, cavity size and packing of molecule.

  13. Structural investigation of ribonuclease A conformational preferences using high pressure protein crystallography

    International Nuclear Information System (INIS)

    Kurpiewska, Katarzyna; Dziubek, Kamil; Katrusiak, Andrzej; Font, Josep; Ribò, Marc; Vilanova, Maria; Lewiński, Krzysztof

    2016-01-01

    Highlights: • A unique crystallographic studies of wild-type and mutated form of the same protein under high pressure. • Compressibility of RNase A molecule is significantly affected by a single amino acid substitution. • High pressure protein crystallography helps understanding protein flexibility and identify conformational substrates. - Abstract: Hydrostatic pressure in range 0.1–1.5 GPa is used to modify biological system behaviour mostly in biophysical studies of proteins in solution. Due to specific influence on the system equilibrium high pressure can act as a filter that enables to identify and investigate higher energy protein conformers. The idea of the presented experiments is to examine the behaviour of RNase A molecule under high pressure before and after introduction of destabilizing mutation. For the first time crystal structures of wild-type bovine pancreatic ribonuclease A and its markedly less stable variant modified at position Ile106 were determined at different pressures. X-ray diffraction experiments at high pressure showed that the secondary structure of RNase A is well preserved even beyond 0.67 GPa at room temperature. Detailed structural analysis of ribonuclease A conformation observed under high pressure revealed that pressure influences hydrogen bonds pattern, cavity size and packing of molecule.

  14. A computer-controlled conformal radiotherapy system. III: graphical simulation and monitoring of treatment delivery

    International Nuclear Information System (INIS)

    Kessler, Marc L.; McShan, Daniel L.; Fraass, Benedick A.

    1995-01-01

    Purpose: Safe and efficient delivery of radiotherapy using computer-controlled machines requires new procedures to design and verify the actual delivery of these treatments. Graphical simulation and monitoring techniques for treatment delivery have been developed for this purpose. Methods and Materials: A graphics-based simulator of the treatment machine and a set of procedures for creating and manipulating treatment delivery scripts are used to simulate machine motions, detect collisions, and monitor machine positions during treatment. The treatment delivery simulator is composed of four components: a three-dimensional dynamic model of the treatment machine; a motion simulation and collision detection algorithm, user-interface widgets that mimic the treatment machine's control and readout devices; and an icon-based interface for creating and manipulating treatment delivery scripts. These components are used in a stand-alone fashion for interactive treatment delivery planning and integrated with a machine control system for treatment implementation and monitoring. Results: A graphics-based treatment delivery simulator and a set of procedures for planning and monitoring computer-controlled treatment delivery have been developed and implemented as part of a comprehensive computer-controlled conformal radiotherapy system. To date, these techniques have been used to design and help monitor computer-controlled treatments on a radiotherapy machine for more than 200 patients. Examples using these techniques for treatment delivery planning and on-line monitoring of machine motions during therapy are described. Conclusion: A system that provides interactive graphics-based tools for defining the sequence of machine motions, simulating treatment delivery including collision detection, and presenting the therapists with continual visual feedback from the treatment machine has been successfully implemented for routine clinical use as part of an overall system for computer

  15. Development of novel conformity indices for quantitative comparison of radiation treatment plans

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Min; Park, So Yeon; Wu, Hong Gyun; Ye, Sung Joon; Kim, Jin Ho; Kim, Jung In [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2013-11-15

    The conformity index (CI) is an indicator to assess the degree of congruence between a shape of reference isodose volume (VRI) and a shape of the target volume (TV). Two concepts are included in the CI, which are the target coverage and the degree of normal tissue sparing in the proximity of the target. Even though this could be verified by a manual review of dose distributions calculated on patient CT images slice by slice, detailed comparisons among several treatment plans would be inconvenient. The conformity could be also verified by reviewing dose-volume histograms (DVHs) of each structure calculated by treatment planning system (TPS). The prerequisite for this is the contouring of not only organs at risk (OARs) but also every structure in a patient body, which is not practical in the clinic. Therefore, a value possible to quantify the conformity was needed, and various studies on CI have been performed. Various CIs have been developed since 1993. Most of them are based on the calculation of the volumes except for the CI suggested by Wu et al. and Cheung et al. which were based on the distance. The aim of this study was to develop new CIs based on the calculations of angles and distances. The CI angle based on the analysis of the angle differences as well as the CIabs{sub d}istance and the CIdistance based on the analysis of the distances between the TV and the VRI were developed and evaluated in this study. The CI distance with Sornatomedins better performances than the CIangle and the CIabs{sub d}istance as well as the conventional CIs in various situations.

  16. Incidence of and factors related to late complications in conformal and conventional radiation treatment of cancer of the prostate

    Energy Technology Data Exchange (ETDEWEB)

    Schultheiss, Timothy E; Hanks, Gerald E; Hunt, Margie A; Lee, W Robert

    1995-06-15

    Purpose: The fundament hypothesis of conformal radiation therapy is that tumor control can be increased by using conformal treatment techniques that allow a higher tumor dose while maintaining an acceptable level of complications. To test this hypothesis, it is necessary first to estimate the incidence of morbidity for both standard and conformal fields. In this study, we examine factors that influence the incidence of late Grade 3 and 4 morbidity in patients treated with conformal and standard radiation treatment for prostate cancer. Methods and Materials: Six hundred sixteen consecutive patients treated with conformal or standard techniques between 1986 and 1994 to doses greater than 65 Gy and with more than 3 months follow-up were analyzed. No patients treated with prostatectomies were included in the analysis. The conformal technique includes special immobilization by a cast, careful identification of the target volume in three dimensions, localization of the inferior border of the prostate using a retrograde urethrogram, and individually shaped portals that conform to the Planning Target Volume (PTV). Multivariate analysis using a proportional hazards model compares differences in the incidence of Radiation Therapy Oncology Group/European Organization for Research and Center Treatment (RTOG/EORTC) Grade 3 and 4 late gastrointestinal (GI) and genitourinary (GU) morbidity by technique, T-stage, grade, age, hormonal treatment, irradiated volume, dose, and comorbid conditions. Grade 3 rectal bleeding was defined as requiring three or more cautery procedures. Results: The overall actuarial incidence of genitourinary (GU) toxicities at 5 years was 3.4%, with the crude incidence being six cases in 616 patients satisfying the selection criteria; for gastrointestinal (GI) toxicities, the overall actuarial incidence was 2.7%, with the crude incidence being 13 cases out of 616 patients. The average time to complication for our patients was 12.8 months for GI toxicity and

  17. Dose escalation using conformal high-dose-rate brachytherapy improves outcome in unfavorable prostate cancer.

    Science.gov (United States)

    Martinez, Alvaro A; Gustafson, Gary; Gonzalez, José; Armour, Elwood; Mitchell, Chris; Edmundson, Gregory; Spencer, William; Stromberg, Jannifer; Huang, Raywin; Vicini, Frank

    2002-06-01

    To overcome radioresistance for patients with unfavorable prostate cancer, a prospective trial of pelvic external beam irradiation (EBRT) interdigitated with dose-escalating conformal high-dose-rate (HDR) prostate brachytherapy was performed. Between November 1991 and August 2000, 207 patients were treated with 46 Gy pelvic EBRT and increasing HDR brachytherapy boost doses (5.50-11.5 Gy/fraction) during 5 weeks. The eligibility criteria were pretreatment prostate-specific antigen level >or=10.0 ng/mL, Gleason score >or=7, or clinical Stage T2b or higher. Patients were divided into 2 dose levels, low-dose biologically effective dose 93 Gy (149 patients). No patient received hormones. We used the American Society for Therapeutic Radiology and Oncology definition for biochemical failure. The median age was 69 years. The mean follow-up for the group was 4.4 years, and for the low and high-dose levels, it was 7.0 and 3.4 years, respectively. The actuarial 5-year biochemical control rate was 74%, and the overall, cause-specific, and disease-free survival rate was 92%, 98%, and 68%, respectively. The 5-year biochemical control rate for the low-dose group was 52%; the rate for the high-dose group was 87% (p failure. The Radiation Therapy Oncology Group Grade 3 gastrointestinal/genitourinary complications ranged from 0.5% to 9%. The actuarial 5-year impotency rate was 51%. Pelvic EBRT interdigitated with transrectal ultrasound-guided real-time conformal HDR prostate brachytherapy boost is both a precise dose delivery system and a very effective treatment for unfavorable prostate cancer. We demonstrated an incremental beneficial effect on biochemical control and cause-specific survival with higher doses. These results, coupled with the low risk of complications, the advantage of not being radioactive after implantation, and the real-time interactive planning, define a new standard for treatment.

  18. The intercomparison of the dose distributions between conformation techniques with pions and photons

    International Nuclear Information System (INIS)

    Karasawa, K.; Nakagawa, K.; Akanuma, A.

    1990-01-01

    To compare conformation radiation treatment with pions vs photons, dose volume histograms (DVH) to the critical organs, including the spinal cord, kidney, and intestine, were examined in a patient with retroperitoneal soft tissue sarcoma. For photon conformation treatment, the following techniques were used: 360 degree rotation conformation technique (photon conformation), 4 fixed field technique (photon 4-field), and 2-axis conformation technique (photon 2-axial conformation). According to the DVH reduction method, complication probability was estimated. The concave portion of the target was conformed by pion conformation treatment, but not by photon conformation treatment. Pion conformation for the intestine showed the best DVH, whereas photon 4-field technique showed the worst DVH. For the kidney, pion conformation showed better DVH as compared with any other photon conformation treatment technique. In the spinal cord, photon 2-axial conformation was far superior, followed by pion conformation and then photon conformation and 4-field technique. A 2-axial technique showed a bigger inhomogeneity inside the target volume which is critical in curative treatment. TD 50 was 72 Gy for pion conformation, 53 Gy for photon conformation, 51 Gy for photon 4-field, and 68 Gy for photon 2-axial conformation. Complication probabilities for these conformation techniques at 60 Gy were 3%, 85%, 97%, and 9%. In view of tumor control probabilities, pion seems to have the biggest therapeutic ratio among these techniques. (N.K.)

  19. Intensity-modulated radiotherapy (IMRT) and conventional three-dimensional conformal radiotherapy for high-grade gliomas: Does IMRT increase the integral dose to normal brain?

    International Nuclear Information System (INIS)

    Hermanto, Ulrich; Frija, Erik K.; Lii, MingFwu J.; Chang, Eric L.; Mahajan, Anita; Woo, Shiao Y.

    2007-01-01

    Purpose: To determine whether intensity-modulated radiotherapy (IMRT) treatment increases the total integral dose of nontarget tissue relative to the conventional three-dimensional conformal radiotherapy (3D-CRT) technique for high-grade gliomas. Methods and Materials: Twenty patients treated with 3D-CRT for glioblastoma multiforme were selected for a comparative dosimetric evaluation with IMRT. Original target volumes, organs at risk (OAR), and dose-volume constraints were used for replanning with IMRT. Predicted isodose distributions, cumulative dose-volume histograms of target volumes and OAR, normal tissue integral dose, target coverage, dose conformity, and normal tissue sparing with 3D-CRT and IMRT planning were compared. Statistical analyses were performed to determine differences. Results: In all 20 patients, IMRT maintained equivalent target coverage, improved target conformity (conformity index [CI] 95% 1.52 vs. 1.38, p mean by 19.8% and D max by 10.7%), optic chiasm (D mean by 25.3% and D max by 22.6%), right optic nerve (D mean by 37.3% and D max by 28.5%), and left optic nerve (D mean by 40.6% and D max by 36.7%), p ≤ 0.01. This was achieved without increasing the total nontarget integral dose by greater than 0.5%. Overall, total integral dose was reduced by 7-10% with IMRT, p < 0.001, without significantly increasing the 0.5-5 Gy low-dose volume. Conclusions: These results indicate that IMRT treatment for high-grade gliomas allows for improved target conformity, better critical tissue sparing, and importantly does so without increasing integral dose and the volume of normal tissue exposed to low doses of radiation

  20. Direct tumor in vivo dosimetry in highly-conformal radiotherapy: A feasibility study of implantable MOSFETs for hypofractionated extracranial treatments using the Cyberknife system

    International Nuclear Information System (INIS)

    Scalchi, Paolo; Righetto, Roberto; Cavedon, Carlo; Francescon, Paolo; Colombo, Federico

    2010-01-01

    Purpose: In highly-conformal radiotherapy, due to the complexity of both beam configurations and dose distributions, traditional in vivo dosimetry is unpractical or even impossible. The ideal dosimeter would be implanted inside the planning treatment volume so that it can directly measure the total delivered dose during each fraction with no additional uncertainty due to calculation models. The aim of this work is to verify if implantable metal oxide semiconductors field effect transistors (MOSFETs) can achieve a sufficient degree of dosimetric accuracy when used inside extracranial targets undergoing radiotherapy treatments using the Cyberknife system. Methods: Based on the preliminary findings of this study, new prototypes for high dose fractionations were developed to reduce the time dependence for long treatment delivery times. These dosimeters were recently cleared and are marketed as DVS-HFT. Multiple measurements were performed using both Virtual Water and water phantoms to characterize implantable MOSFETs under the Cyberknife beams, and included the reference-dosimetry consistency, the dependence of the response on the collimator size, on the daily delivered dose, and the time irradiation modality. Finally a Cyberknife prostate treatment simulation using a body phantom was conducted, and both MOSFET and ionization readings were compared to Monte Carlo calculations. The feasibility analysis was conducted based on the ratios of the absorbed dose divided by the dose reading, named as ''further calibration factor'' (FCF). Results: The average FCFs resulted to be 0.98 for the collimator dependence test, and about 1.00 for the reference-dosimetry test, the dose-dependence test, and the time-dependence test. The average FCF of the prostate treatment simulation test was 0.99. Conclusions: The obtained results are well within DVS specifications, that is, the factory calibration is still valid for such kind of treatments using the Cyberknife system, with no need of

  1. Effect of High-Pressure Treatment on Catalytic and Physicochemical Properties of Pepsin.

    Science.gov (United States)

    Wang, Jianan; Bai, Tenghui; Ma, Yaping; Ma, Hanjun

    2017-10-11

    For a long time, high-pressure treatment has been used to destroy the compact structures of natural proteins in order to promote subsequent enzymatic hydrolysis. However, there are few reports evaluating the feasibility of directly improving the catalytic capability of proteases by using high-pressure treatments. In this study, the effects of high-pressure treatment on the catalytic capacity and structure of pepsin were investigated, and the relationship between its catalytic properties and changes in its physicochemical properties was explored. It was found that high-pressure treatment could lead to changes of the sulfhydryl group/disulfide bond content, hydrophobicity, hydrodynamic radius, intrinsic viscosity, and subunit composition of pepsin, and the conformational change of pepsin resulted in improvement to its enzymatic activity and hydrolysis efficiency, which had an obvious relationship with the high-pressure treatment conditions.

  2. A computer-controlled conformal radiotherapy system. IV: Electronic chart

    International Nuclear Information System (INIS)

    Fraass, Benedick A.; McShan, Daniel L.; Matrone, Gwynne M.; Weaver, Tamar A.; Lewis, James D.; Kessler, Marc L.

    1995-01-01

    Purpose: The design and implementation of a system for electronically tracking relevant plan, prescription, and treatment data for computer-controlled conformal radiation therapy is described. Methods and Materials: The electronic charting system is implemented on a computer cluster coupled by high-speed networks to computer-controlled therapy machines. A methodical approach to the specification and design of an integrated solution has been used in developing the system. The electronic chart system is designed to allow identification and access of patient-specific data including treatment-planning data, treatment prescription information, and charting of doses. An in-house developed database system is used to provide an integrated approach to the database requirements of the design. A hierarchy of databases is used for both centralization and distribution of the treatment data for specific treatment machines. Results: The basic electronic database system has been implemented and has been in use since July 1993. The system has been used to download and manage treatment data on all patients treated on our first fully computer-controlled treatment machine. To date, electronic dose charting functions have not been fully implemented clinically, requiring the continued use of paper charting for dose tracking. Conclusions: The routine clinical application of complex computer-controlled conformal treatment procedures requires the management of large quantities of information for describing and tracking treatments. An integrated and comprehensive approach to this problem has led to a full electronic chart for conformal radiation therapy treatments

  3. Conformal Radiotherapy in the Treatment of Advanced Juvenile Nasopharyngeal Angiofibroma With Intracranial Extension: An Institutional Experience

    International Nuclear Information System (INIS)

    Chakraborty, Santam; Ghoshal, Sushmita; Patil, Vijay Maruti; Oinam, Arun Singh; Sharma, Suresh C.

    2011-01-01

    Purpose: To describe the results of conformal radiotherapy in advanced juvenile nasopharyngeal angiofibroma in a tertiary care institution. Methods and Materials: Retrospective chart review was conducted for 8 patients treated with conformal radiotherapy between 2006 and 2009. The median follow-up was 17 months. All patients had Stage IIIB disease with intracranial extension. Radiotherapy was considered as treatment because patients were deemed inoperable owing to extensive intracranial/intraorbital extension or proximity to optic nerve. All but 1 patient were treated with intensity-modulated radiotherapy using seven coplanar fields. Median (range) dose prescribed was 39.6 (30-46) Gy. Actuarial analysis of local control and descriptive analysis of toxicity profile was conducted. Results: Despite the large and complex target volume (median planning target volume, 292 cm 3 ), intensity-modulated radiotherapy achieved conformal dose distributions (median van't Reit index, 0.66). Significant sparing of the surrounding organs at risk was obtained. No significant Grade 3/4 toxicities were experienced during or after treatment. Actual local control at 2 years was 87.5%. One patient died 1 month after radiotherapy secondary to massive epistaxis. The remaining 7 patients had progressive resolution of disease and were symptom-free at last follow-up. Persistent rhinitis was the only significant toxicity, seen in 1 patient. Conclusions: Conformal radiotherapy results in good local control with minimal acute and late side effects in juvenile nasopharyngeal angiofibromas, even in the presence of advanced disease.

  4. A dose homogeneity and conformity evaluation between ViewRay and pinnacle-based linear accelerator IMRT treatment plans

    International Nuclear Information System (INIS)

    Saenz, Daniel L.; Paliwal, Bhudatt R.; Bayouth, John E.

    2014-01-01

    ViewRay, a novel technology providing soft-tissue imaging during radiotherapy is investigated for treatment planning capabilities assessing treatment plan dose homogeneity and conformity compared with linear accelerator plans. ViewRay offers both adaptive radiotherapy and image guidance. The combination of cobalt-60 ( 60 Co) with 0.35 Tesla magnetic resonance imaging (MRI) allows for magnetic resonance (MR)-guided intensity-modulated radiation therapy (IMRT) delivery with multiple beams. This study investigated head and neck, lung, and prostate treatment plans to understand what is possible on ViewRay to narrow focus toward sites with optimal dosimetry. The goal is not to provide a rigorous assessment of planning capabilities, but rather a first order demonstration of ViewRay planning abilities. Images, structure sets, points, and dose from treatment plans created in Pinnacle for patients in our clinic were imported into ViewRay. The same objectives were used to assess plan quality and all critical structures were treated as similarly as possible. Homogeneity index (HI), conformity index (CI), and volume receiving 60 Co ViewRay treatments planned with its Monte Carlo treatment planning software were comparable with 6 MV plans computed with convolution superposition algorithm on Pinnacle treatment planning system. (author)

  5. A dose homogeneity and conformity evaluation between ViewRay and pinnacle-based linear accelerator IMRT treatment plans.

    Science.gov (United States)

    Saenz, Daniel L; Paliwal, Bhudatt R; Bayouth, John E

    2014-04-01

    ViewRay, a novel technology providing soft-tissue imaging during radiotherapy is investigated for treatment planning capabilities assessing treatment plan dose homogeneity and conformity compared with linear accelerator plans. ViewRay offers both adaptive radiotherapy and image guidance. The combination of cobalt-60 (Co-60) with 0.35 Tesla magnetic resonance imaging (MRI) allows for magnetic resonance (MR)-guided intensity-modulated radiation therapy (IMRT) delivery with multiple beams. This study investigated head and neck, lung, and prostate treatment plans to understand what is possible on ViewRay to narrow focus toward sites with optimal dosimetry. The goal is not to provide a rigorous assessment of planning capabilities, but rather a first order demonstration of ViewRay planning abilities. Images, structure sets, points, and dose from treatment plans created in Pinnacle for patients in our clinic were imported into ViewRay. The same objectives were used to assess plan quality and all critical structures were treated as similarly as possible. Homogeneity index (HI), conformity index (CI), and volume receiving ViewRay treatments planned with its Monte Carlo treatment planning software were comparable with 6 MV plans computed with convolution superposition algorithm on Pinnacle treatment planning system.

  6. A dose homogeneity and conformity evaluation between ViewRay and pinnacle-based linear accelerator IMRT treatment plans

    Directory of Open Access Journals (Sweden)

    Daniel L Saenz

    2014-01-01

    Full Text Available ViewRay, a novel technology providing soft-tissue imaging during radiotherapy is investigated for treatment planning capabilities assessing treatment plan dose homogeneity and conformity compared with linear accelerator plans. ViewRay offers both adaptive radiotherapy and image guidance. The combination of cobalt-60 (Co-60 with 0.35 Tesla magnetic resonance imaging (MRI allows for magnetic resonance (MR-guided intensity-modulated radiation therapy (IMRT delivery with multiple beams. This study investigated head and neck, lung, and prostate treatment plans to understand what is possible on ViewRay to narrow focus toward sites with optimal dosimetry. The goal is not to provide a rigorous assessment of planning capabilities, but rather a first order demonstration of ViewRay planning abilities. Images, structure sets, points, and dose from treatment plans created in Pinnacle for patients in our clinic were imported into ViewRay. The same objectives were used to assess plan quality and all critical structures were treated as similarly as possible. Homogeneity index (HI, conformity index (CI, and volume receiving <20% of prescription dose (DRx were calculated to assess the plans. The 95% confidence intervals were recorded for all measurements and presented with the associated bars in graphs. The homogeneity index (D5/D95 had a 1-5% inhomogeneity increase for head and neck, 3-8% for lung, and 4-16% for prostate. CI revealed a modest conformity increase for lung. The volume receiving 20% of the prescription dose increased 2-8% for head and neck and up to 4% for lung and prostate. Overall, for head and neck Co-60 ViewRay treatments planned with its Monte Carlo treatment planning software were comparable with 6 MV plans computed with convolution superposition algorithm on Pinnacle treatment planning system.

  7. The New Nitinol Conformable Self-Expandable Metal Stents for Malignant Colonic Obstruction: A Pilot Experience as Bridge to Surgery Treatment

    Directory of Open Access Journals (Sweden)

    Roberto Di Mitri

    2014-01-01

    Full Text Available Introduction. Self-expandable metal stents (SEMS are a nonsurgical option for treatment of malignant colorectal obstruction also as a bridge to surgery approach. The new nitinol conformable stent has improved clinical outcomes in these kinds of patients. We report a pilot experience with nitinol conformable SEMS placement as bridge to surgery treatment in patients with colorectal obstruction. Materials and Methods. Between April and August 2012, we collected data on colonic nitinol conformable SEMS placement in a cohort of consecutive symptomatic patients, with malignant colorectal obstruction, who were treated as a bridge to surgery. Technical success, clinical success, and adverse events were recorded. Results. Ten patients (7 male (70%, with a mean age of 69.2 ± 10.1, were evaluated. The mean length of the stenosis was 3.6 ± 0.6 cm. Five patients (50% were treated on an emergency basis. The median time from stent placement to surgery was 16 days (interquartile range 7–21. Technical and clinical success was achieved in all patients with a significant early improvement of symptoms. No adverse events due to the SEMS placement were observed. Conclusion. This pilot study confirmed the important role of nitinol conformable SEMS as a bridge to surgery option in the treatment of symptomatic malignant colorectal obstruction.

  8. Conformal Nets II: Conformal Blocks

    Science.gov (United States)

    Bartels, Arthur; Douglas, Christopher L.; Henriques, André

    2017-08-01

    Conformal nets provide a mathematical formalism for conformal field theory. Associated to a conformal net with finite index, we give a construction of the `bundle of conformal blocks', a representation of the mapping class groupoid of closed topological surfaces into the category of finite-dimensional projective Hilbert spaces. We also construct infinite-dimensional spaces of conformal blocks for topological surfaces with smooth boundary. We prove that the conformal blocks satisfy a factorization formula for gluing surfaces along circles, and an analogous formula for gluing surfaces along intervals. We use this interval factorization property to give a new proof of the modularity of the category of representations of a conformal net.

  9. Comparison of static conformal field with multiple noncoplanar arc techniques for stereotactic radiosurgery or stereotactic radiotherapy

    International Nuclear Information System (INIS)

    Hamilton, Russell J.; Kuchnir, Franca T.; Sweeney, Patrick; Rubin, Steven J.; Dujovny, Manuel; Pelizzari, Charles A.; Chen, George T. Y.

    1995-01-01

    Purpose: Compare the use of static conformal fields with the use of multiple noncoplanar arcs for stereotactic radiosurgery or stereotactic radiotherapy treatment of intracranial lesions. Evaluate the efficacy of these treatment techniques to deliver dose distributions comparable to those considered acceptable in current radiotherapy practice. Methods and Materials: A previously treated radiosurgery case of a patient presenting with an irregularly shaped intracranial lesion was selected. Using a three-dimensional (3D) treatment-planning system, treatment plans using a single isocenter multiple noncoplanar arc technique and multiple noncoplanar conformal static fields were generated. Isodose distributions and dose volume histograms (DVHs) were computed for each treatment plan. We required that the 80% (of maximum dose) isodose surface enclose the target volume for all treatment plans. The prescription isodose was set equal to the minimum target isodose. The DVHs were analyzed to evaluate and compare the different treatment plans. Results: The dose distribution in the target volume becomes more uniform as the number of conformal fields increases. The volume of normal tissue receiving low doses (> 10% of prescription isodose) increases as the number of static fields increases. The single isocenter multiple arc plan treats the greatest volume of normal tissue to low doses, approximately 1.6 times more volume than that treated by four static fields. The volume of normal tissue receiving high (> 90% of prescription isodose) and intermediate (> 50% of prescription isodose) doses decreases by 29 and 22%, respectively, as the number of static fields is increased from four to eight. Increasing the number of static fields to 12 only further reduces the high and intermediate dose volumes by 10 and 6%, respectively. The volume receiving the prescription dose is more than 3.5 times larger than the target volume for all treatment plans. Conclusions: Use of a multiple noncoplanar

  10. Theoretical investigation of the conformational space of baicalin.

    Science.gov (United States)

    Martínez Medina, Juan J; Ferrer, Evelina G; Williams, Patricia A M; Okulik, Nora B

    2017-09-01

    Flavonoids are a large group of polyphenolic compounds ubiquitously present in plants. They are important components of human diet. They are recognized as potential drug candidates to be used in the treatment and prevention of a lot of pathological disorders, due to their protective effects. Baicalin (7-glucuronic acid 5, 6-dihydroxyflavone) is one of the main single active constituents isolated from the dried roots of Scutellaria baicalensis Georgi. The great interest on this flavonoid is due to its various pharmacological properties, such as antioxidant, antimicrobial, anti-inflammatory, anticancer and so on, and its high accumulation in the roots of S. baicalensis. The aim of our work was to analyze the geometric and electronic properties of baicalin conformers (BCL), thus performing a complete search on the conformational space of this flavonoid in gas phase and in aqueous solution. The results indicate that the conformational space of baicalin is formed by eight conformers in gas phase and five conformers in aqueous solution optimized at B3LYP/6-311++G** theory level. BCLa2 TT and BCLa1 TT conformers have low stability in gas phase and very high stability in aqueous solution. This variation is related to a modification in the τ 1 angle that represents the relative position of the glucuronide unit respect to the central rings of the flavan nucleus (A and C). This modification was successfully explained by examining the changes in the hydrogen bond (HB) interactions that occur in the region around the hydroxyl group located in position 6 of ring A. Besides, the molecular electrostatic potential (MEP) and frontier molecular orbital (FMO) analyses indicate that BCLa2 TT and BCLa1 TT conformers are the most favorable conformers for interacting with positively charged species (such as metal ions) in aqueous media (such as biological fluids). Copyright © 2017 Elsevier Inc. All rights reserved.

  11. A computer-controlled conformal radiotherapy system I: overview

    International Nuclear Information System (INIS)

    Fraass, Benedick A.; McShan, Daniel L.; Kessler, Marc L.; Matrone, Gwynne M.; Lewis, James D.; Weaver, Tamar A.

    1995-01-01

    Purpose: Equipment developed for use with computer-controlled conformal radiotherapy (CCRT) treatment techniques, including multileaf collimators and/or computer-control systems for treatment machines, are now available. The purpose of this work is to develop a system that will allow the safe, efficient, and accurate delivery of CCRT treatments as routine clinical treatments, and permit modifications of the system so that the delivery process can be optimized. Methods and Materials: The needs and requirements for a system that can fully support modern computer-controlled treatment machines equipped with multileaf collimators and segmental or dynamic conformal therapy capabilities have been analyzed and evaluated. This analysis has been used to design and then implement a complete approach to the delivery of CCRT treatments. Results: The computer-controlled conformal radiotherapy system (CCRS) described here consists of a process for the delivery of CCRT treatments, and a complex software system that implements the treatment process. The CCRS system described here includes systems for plan transfer, treatment delivery planning, sequencing of the actual treatment delivery process, graphical simulation and verification tools, as well as an electronic chart that is an integral part of the system. The CCRS system has been implemented for use with a number of different treatment machines. The system has been used clinically for more than 2 years to perform CCRT treatments for more than 200 patients. Conclusions: A comprehensive system for the implementation and delivery of computer-controlled conformal radiation therapy (CCRT) plans has been designed and implemented for routine clinical use with multisegment, computer-controlled, multileaf-collimated conformal therapy. The CCRS system has been successfully implemented to perform these complex treatments, and is considered quite important to the clinical use of modern computer-controlled treatment techniques

  12. Factors influencing conformity index in radiotherapy for non-small cell lung cancer.

    LENUS (Irish Health Repository)

    Brennan, Sinead M

    2010-01-01

    The radiotherapy conformity index (CI) is a useful tool to quantitatively assess the quality of radiotherapy treatment plans, and represents the relationship between isodose distributions and target volume. A conformity index of unity implies high planning target volume (PTV) coverage and minimal unnecessary irradiation of surrounding tissues. We performed this analysis to describe the CI for lung cancer 3-dimensional conformal radiotherapy (3DCRT) and to identify clinical and technical determinants of CI, as it is not known which factors are associated with good quality 3D conformal radiotherapy treatment planning. Radiotherapy treatment plans from a database of 52 patients with inoperable Stage 1 to 3b lung cancer, on a hypofractionated 3DCRT trial were evaluated. A CI was calculated for all plans using the definition of the ICRU 62:CI = (TV\\/PTV), which is the quotient of the treated volume (TV) and the PTV. Data on patient, tumor, and planning variables, which could influence CI, were recorded and analyzed. Mean CI was 2.01 (range = 1.06-3.8). On univariate analysis, PTV (p = 0.023), number of beams (p = 0.036), medial vs. lateral tumor location (p = 0.016), and increasing tumor stage (p = 0.041) were associated with improved conformity. On multiple regression analysis, factors found to be associated with CI included central vs. peripheral tumor location (p = 0.041) and PTV size (p = 0.058). The term 3DCRT is used routinely in the literature, without any indication of the degree of conformality. We recommend routine reporting of conformity indices. Conformity indices may be affected by both planning variables and tumor factors.

  13. TH-EF-BRB-04: 4π Dynamic Conformal Arc Therapy Dynamic Conformal Arc Therapy (DCAT) for SBRT

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, T; Long, T; Tian, Z.; Yan, Y; Jiang, S; Gu, X [UT Southwestern Medical Center, Dallas, TX (United States); Modiri, A; Sawant, A [University of Maryland in Baltimore, Baltimore, MD (United States)

    2016-06-15

    Purpose: To develop an efficient and effective trajectory optimization methodology for 4π dynamic conformal arc treatment (4π DCAT) with synchronized gantry and couch motion; and to investigate potential clinical benefits for stereotactic body radiation therapy (SBRT) to breast, lung, liver and spine tumors. Methods: The entire optimization framework for 4π DCAT inverse planning consists of two parts: 1) integer programming algorithm and 2) particle swarm optimization (PSO) algorithm. The integer programming is designed to find an optimal solution for arc delivery trajectory with both couch and gantry rotation, while PSO minimize a non-convex objective function based on the selected trajectory and dose-volume constraints. In this study, control point interaction is explicitly taken into account. Beam trajectory was modeled as a series of control points connected together to form a deliverable path. With linear treatment planning objectives, a mixed-integer program (MIP) was formulated. Under mild assumptions, the MIP is tractable. Assigning monitor units to control points along the path can be integrated into the model and done by PSO. The developed 4π DCAT inverse planning strategy is evaluated on SBRT cases and compared to clinically treated plans. Results: The resultant dose distribution of this technique was evaluated between 3D conformal treatment plan generated by Pinnacle treatment planning system and 4π DCAT on a lung SBRT patient case. Both plans share the same scale of MU, 3038 and 2822 correspondingly to 3D conformal plan and 4π DCAT. The mean doses for most of OARs were greatly reduced at 32% (cord), 70% (esophagus), 2.8% (lung) and 42.4% (stomach). Conclusion: Initial results in this study show the proposed 4π DCAT treatment technique can achieve better OAR sparing and lower MUs, which indicates that the developed technique is promising for high dose SBRT to reduce the risk of secondary cancer.

  14. Clinical Studies on conformal radiotherapy combined with epidermal ...

    African Journals Online (AJOL)

    in second-line treatment of non-small cell lung cancer ... receptor-tyrosine kinase inhibitor (EGFR-TKI) in the second-line treatment of non-small cell ... were divided into two groups: 106 patients were treated with conformal ... Conformal radiotherapy, Targeted therapy, Survival rate .... regression model was used for survival.

  15. Dosimetric Verification and Evaluation of the 3-D Conformal Parotid Gland-Sparing Irradiation Technique for Bilateral Neck Treatment at University Hospital Centre Zagreb

    International Nuclear Information System (INIS)

    Kovacevic, N; Hrsak, H.; Bibic, J.

    2011-01-01

    3-D Conformal Parotid Gland-Sparing Irradiation Technique for Bilateral Neck (ConPas) is an alternative to Intensity-modulated radiotherapy (IMRT), and is in routine use at University Hospital Centre Rebro (KBC-Rebro), Zagreb. This technique includes highly asymmetric wedged conformal multi-leaf fields and demands very precise application. The aim of this paper is to present the dosimetric verification method of ConPas (and evaluation of ConPas applicability) as performed at KBC, taking into account the precision of the Treatment Planning System (TPS), possibilities of linear accelerator and patient set-up error. Results for two patients are shown in some details.ConPas is a rather sophisticated method and demands high precision in the whole radiotherapy process. Verification of ConPas using IMRT Verification Matrix Phantom shows good agreement between measured and predicted doses inside and outside PTV regions of the head and neck. Furthermore, a careful track of the positioning during the treatment shows that the overall set-up error is very small (practically negligible). When possible, one parotid gland may be partially spared, and therefore its function preserved at least to some extent. (author)

  16. Microscopic silicon-based lateral high-aspect-ratio structures for thin film conformality analysis

    International Nuclear Information System (INIS)

    Gao, Feng; Arpiainen, Sanna; Puurunen, Riikka L.

    2015-01-01

    Film conformality is one of the major drivers for the interest in atomic layer deposition (ALD) processes. This work presents new silicon-based microscopic lateral high-aspect-ratio (LHAR) test structures for the analysis of the conformality of thin films deposited by ALD and by other chemical vapor deposition means. The microscopic LHAR structures consist of a lateral cavity inside silicon with a roof supported by pillars. The cavity length (e.g., 20–5000 μm) and cavity height (e.g., 200–1000 nm) can be varied, giving aspect ratios of, e.g., 20:1 to 25 000:1. Film conformality can be analyzed with the microscopic LHAR by several means, as demonstrated for the ALD Al 2 O 3 and TiO 2 processes from Me 3 Al/H 2 O and TiCl 4 /H 2 O. The microscopic LHAR test structures introduced in this work expose a new parameter space for thin film conformality investigations expected to prove useful in the development, tuning and modeling of ALD and other chemical vapor deposition processes

  17. Dose escalation using conformal high-dose-rate brachytherapy improves outcome in unfavorable prostate cancer

    International Nuclear Information System (INIS)

    Martinez, Alvaro A.; Gustafson, Gary; Gonzalez, Jose; Armour, Elwood; Mitchell, Chris; Edmundson, Gregory; Spencer, William; Stromberg, Jannifer; Huang, Raywin; Vicini, Frank

    2002-01-01

    Purpose: To overcome radioresistance for patients with unfavorable prostate cancer, a prospective trial of pelvic external beam irradiation (EBRT) interdigitated with dose-escalating conformal high-dose-rate (HDR) prostate brachytherapy was performed. Methods and Materials: Between November 1991 and August 2000, 207 patients were treated with 46 Gy pelvic EBRT and increasing HDR brachytherapy boost doses (5.50-11.5 Gy/fraction) during 5 weeks. The eligibility criteria were pretreatment prostate-specific antigen level ≥10.0 ng/mL, Gleason score ≥7, or clinical Stage T2b or higher. Patients were divided into 2 dose levels, low-dose biologically effective dose 93 Gy (149 patients). No patient received hormones. We used the American Society for Therapeutic Radiology and Oncology definition for biochemical failure. Results: The median age was 69 years. The mean follow-up for the group was 4.4 years, and for the low and high-dose levels, it was 7.0 and 3.4 years, respectively. The actuarial 5-year biochemical control rate was 74%, and the overall, cause-specific, and disease-free survival rate was 92%, 98%, and 68%, respectively. The 5-year biochemical control rate for the low-dose group was 52%; the rate for the high-dose group was 87% (p<0.001). Improvement occurred in the cause-specific survival in favor of the brachytherapy high-dose level (p=0.014). On multivariate analysis, a low-dose level, higher Gleason score, and higher nadir value were associated with increased biochemical failure. The Radiation Therapy Oncology Group Grade 3 gastrointestinal/genitourinary complications ranged from 0.5% to 9%. The actuarial 5-year impotency rate was 51%. Conclusion: Pelvic EBRT interdigitated with transrectal ultrasound-guided real-time conformal HDR prostate brachytherapy boost is both a precise dose delivery system and a very effective treatment for unfavorable prostate cancer. We demonstrated an incremental beneficial effect on biochemical control and cause

  18. Conformal coating of amorphous silicon and germanium by high pressure chemical vapor deposition for photovoltaic fabrics

    Science.gov (United States)

    Ji, Xiaoyu; Cheng, Hiu Yan; Grede, Alex J.; Molina, Alex; Talreja, Disha; Mohney, Suzanne E.; Giebink, Noel C.; Badding, John V.; Gopalan, Venkatraman

    2018-04-01

    Conformally coating textured, high surface area substrates with high quality semiconductors is challenging. Here, we show that a high pressure chemical vapor deposition process can be employed to conformally coat the individual fibers of several types of flexible fabrics (cotton, carbon, steel) with electronically or optoelectronically active materials. The high pressure (˜30 MPa) significantly increases the deposition rate at low temperatures. As a result, it becomes possible to deposit technologically important hydrogenated amorphous silicon (a-Si:H) from silane by a simple and very practical pyrolysis process without the use of plasma, photochemical, hot-wire, or other forms of activation. By confining gas phase reactions in microscale reactors, we show that the formation of undesired particles is inhibited within the microscale spaces between the individual wires in the fabric structures. Such a conformal coating approach enables the direct fabrication of hydrogenated amorphous silicon-based Schottky junction devices on a stainless steel fabric functioning as a solar fabric.

  19. Optimization of stereotactically-guided conformal treatment planning of sellar and parasellar tumors, based on normal brain dose volume histograms

    International Nuclear Information System (INIS)

    Perks, Julian R.; Jalali, Rakesh; Cosgrove, Vivian P.; Adams, Elizabeth J.; Shepherd, Stephen F.; Warrington, Alan P.; Brada, Michael

    1999-01-01

    Purpose: To investigate the optimal treatment plan for stereo tactically-guided conformal radiotherapy (SCRT) of sellar and parasellar lesions, with respect to sparing normal brain tissue, in the context of routine treatment delivery, based on dose volume histogram analysis. Methods and Materials: Computed tomography (CT) data sets for 8 patients with sellar- and parasellar-based tumors (6 pituitary adenomas and 2 meningiomas) have been used in this study. Treatment plans were prepared for 3-coplanar and 3-, 4-, 6-, and 30-noncoplanar-field arrangements to obtain 95% isodose coverage of the planning target volume (PTV) for each plan. Conformal shaping was achieved by customized blocks generated with the beams eye view (BEV) facility. Dose volume histograms (DVH) were calculated for the normal brain (excluding the PTV), and comparisons made for normal tissue sparing for all treatment plans at ≥80%, ≥60%, and ≥40% of the prescribed dose. Results: The mean volume of normal brain receiving ≥80% and ≥60% of the prescribed dose decreased by 22.3% (range 14.8-35.1%, standard deviation σ = 7.5%) and 47.6% (range 25.8-69.1%, σ 13.2%), respectively, with a 4-field noncoplanar technique when compared with a conventional 3-field coplanar technique. Adding 2 further fields, from 4-noncoplanar to 6-noncoplanar fields reduced the mean normal brain volume receiving ≥80% of the prescribed dose by a further 4.1% (range -6.5-11.8%, σ = 6.4%), and the volume receiving ≥60% by 3.3% (range -5.5-12.2%, σ = 5.4%), neither of which were statistically significant. Each case must be considered individually however, as a wide range is seen in the volume spared when increasing the number of fields from 4 to 6. Comparing the 4- and 6-field noncoplanar techniques to a 30-field conformal field approach (simulating a dynamic arc plan) revealed near-equivalent normal tissue sparing. Conclusion: Four to six widely spaced, fixed-conformal fields provide the optimum class solution

  20. The comparison of 5-field conformal radiotherapy techniques for the treatment of prostate cancer: The best for femoral head sparing

    International Nuclear Information System (INIS)

    Zare, Mahkameh; Lashkari, Marzieh; Ghalehtaki, Reza; Ghasemi, Arash; Dehghan Manshadi, Hamidreza; Mir, Ali; Noorollahi, Somayeh; Alamolhoda, Mahboobeh

    2016-01-01

    External radiotherapy is a standard treatment procedure for localized prostate cancer. Given the relatively high long term survival treatment complications have been brought in center of attention. In this planning study, between 2012 and 2014, CT simulation data of 90 consecutive high-risk prostate cancer patients were collected. In the first phase, all were planned for whole pelvis irradiation up to 46Gy in 23 daily fractions. In the second phase, only the prostate gland was the target of radiation. Next, the subjects were divided randomly into three groups and each received a unique 5field conformal radiation plan including Plan A (Gantry angle: 0, 60, 120, 240, and 300), Plan B (Gantry angles: 0, 90, 120, 240, and 270) and Plan C (Gantry angles: 0, 60, 90, 270, and 300). The total dose was 70Gy. For each patient, the rectum, bladder, and both femoral heads were contoured as the at risk organs (OAR). From dose volume histograms, the proportional dose of PTV V100, the bladder and rectum V80 and V90 and femoral head V50 and V100 were calculated in all subjects and compared across plans. A statistically significant difference in the femoral head V50 and V100 was found between our studied 5field plans so that in Plan A (beam angles: 0, 60, 120, 240 and 300) less dose was received by both heads of femur. This study suggests that 5 field treatment planning including an anterior, two anterior oblique and two posterior oblique portals to be more proper for 3D conformal radiotherapy in order to spare femoral head with acceptable PTV coverage, and bladder and rectal doses.

  1. Narrowband NIR-Induced In Situ Generation of the High-Energy Trans Conformer of Trichloroacetic Acid Isolated in Solid Nitrogen and its Spontaneous Decay by Tunneling to the Low-Energy Cis Conformer

    Directory of Open Access Journals (Sweden)

    R. F. G. Apóstolo

    2015-12-01

    Full Text Available The monomeric form of trichloroacetic acid (CCl3COOH; TCA was isolated in a cryogenic nitrogen matrix (15 K and the higher energy trans conformer (O=C–O–H dihedral: 180° was generated in situ by narrowband near-infrared selective excitation the 1st OH stretching overtone of the low-energy cis conformer (O=C–O–H dihedral: 0°. The spontaneous decay, by tunneling, of the generated high-energy conformer into the cis form was then evaluated and compared with those observed previously for the trans conformers of acetic and formic acids in identical experimental conditions. The much faster decay of the high-energy conformer of TCA compared to both formic and acetic acids (by ~35 and ca. 25 times, respectively was found to correlate well with the lower energy barrier for the trans→cis isomerization in the studied compound. The experimental studies received support from quantum chemistry calculations undertaken at the DFT(B3LYP/cc-pVDZ level of approximation, which allowed a detailed characterization of the potential energy surface of the molecule and the detailed assignment of the infrared spectra of the two conformers.

  2. A dose homogeneity and conformity evaluation between ViewRay and pinnacle-based linear accelerator IMRT treatment plans

    OpenAIRE

    Daniel L Saenz; Bhudatt R Paliwal; John E Bayouth

    2014-01-01

    ViewRay, a novel technology providing soft-tissue imaging during radiotherapy is investigated for treatment planning capabilities assessing treatment plan dose homogeneity and conformity compared with linear accelerator plans. ViewRay offers both adaptive radiotherapy and image guidance. The combination of cobalt-60 (Co-60) with 0.35 Tesla magnetic resonance imaging (MRI) allows for magnetic resonance (MR)-guided intensity-modulated radiation therapy (IMRT) delivery with multiple beams. This ...

  3. A treatment planning study comparing whole breast radiation therapy against conformal, IMRT and tomotherapy for accelerated partial breast irradiation

    International Nuclear Information System (INIS)

    Oliver, Mike; Chen, Jeff; Wong, Eugene; Van Dyk, Jake; Perera, Francisco

    2007-01-01

    Purpose and background: Conventional early breast cancer treatment consists of a lumpectomy followed by whole breast radiation therapy. Accelerated partial breast irradiation (APBI) is an investigational approach to post-lumpectomy radiation for early breast cancer. The purpose of this study is to compare four external beam APBI techniques, including tomotherapy, with conventional whole breast irradiation for their radiation conformity index, dose homogeneity index, and dose to organs at risk. Methods and materials: Small-field tangents, three-dimensional conformal radiation therapy, intensity-modulated radiation therapy and helical tomotherapy were compared for each of 15 patients (7 right, 8 left). One radiation conformity and two dose homogeneity indices were used to evaluate the dose to the target. The mean dose to organs at risk was also evaluated. Results: All proposed APBI techniques improved the conformity index significantly over whole breast tangents while maintaining dose homogeneity and without a significant increase in dose to organs at risk. Conclusion: The four-field IMRT plan produced the best dosimetric results; however this technique would require appropriate respiratory motion management. An alternative would be to use a four-field conformal technique that is less sensitive to the effects of respiratory motion

  4. Conformational analysis by intersection: CONAN.

    Science.gov (United States)

    Smellie, Andrew; Stanton, Robert; Henne, Randy; Teig, Steve

    2003-01-15

    As high throughput techniques in chemical synthesis and screening improve, more demands are placed on computer assisted design and virtual screening. Many of these computational methods require one or more three-dimensional conformations for molecules, creating a demand for a conformational analysis tool that can rapidly and robustly cover the low-energy conformational spaces of small molecules. A new algorithm of intersection is presented here, which quickly generates (on average heuristics are applied after intersection to generate a small representative collection of conformations that span the conformational space. In a study of approximately 97,000 randomly selected molecules from the MDDR, results are presented that explore these conformations and their ability to cover low-energy conformational space. Copyright 2002 Wiley Periodicals, Inc. J Comput Chem 24: 10-20, 2003

  5. Conformation radiotherapy with eccentric multi-leaves, (1)

    International Nuclear Information System (INIS)

    Obata, Yasunori; Sakuma, Sadayuki.

    1986-01-01

    In order to extend the application of the conformation radiotherapy, the eccentric multi-leaves are equipped with the linear accelerator. The information of the position of the collimators and the dose distribution of the eccentric conformation radiotherapy are calculated by the improved algorism of the treatment planning system. In simple cases, the dose distributions for the distant region from the rotational center are measured and compared with the calculated values. Both distributions are well coincided with the error of about 5 % in the high dose region and 10 % in the low dose region. In eccentric conformation radiotherapy, it is difficult to deliver the planned dose to the lesion. The dose increases with the distance of the target area from the rotational center. And the measured value and the calculated value are well coincided with 1 % error. So after getting the dose ratio of the rotational center to the target area, the calculated dose can be delivered to the rotational center. The advantages of the eccentric conformation radiotherapy are a good coincidence of target area and treated area, a partial shielding and a hollow out technique without absorber. The limitation of the movement of the collimator from center is 5 cm at 1 m SCD. (author)

  6. Benchmarking Commercial Conformer Ensemble Generators.

    Science.gov (United States)

    Friedrich, Nils-Ole; de Bruyn Kops, Christina; Flachsenberg, Florian; Sommer, Kai; Rarey, Matthias; Kirchmair, Johannes

    2017-11-27

    We assess and compare the performance of eight commercial conformer ensemble generators (ConfGen, ConfGenX, cxcalc, iCon, MOE LowModeMD, MOE Stochastic, MOE Conformation Import, and OMEGA) and one leading free algorithm, the distance geometry algorithm implemented in RDKit. The comparative study is based on a new version of the Platinum Diverse Dataset, a high-quality benchmarking dataset of 2859 protein-bound ligand conformations extracted from the PDB. Differences in the performance of commercial algorithms are much smaller than those observed for free algorithms in our previous study (J. Chem. Inf. 2017, 57, 529-539). For commercial algorithms, the median minimum root-mean-square deviations measured between protein-bound ligand conformations and ensembles of a maximum of 250 conformers are between 0.46 and 0.61 Å. Commercial conformer ensemble generators are characterized by their high robustness, with at least 99% of all input molecules successfully processed and few or even no substantial geometrical errors detectable in their output conformations. The RDKit distance geometry algorithm (with minimization enabled) appears to be a good free alternative since its performance is comparable to that of the midranked commercial algorithms. Based on a statistical analysis, we elaborate on which algorithms to use and how to parametrize them for best performance in different application scenarios.

  7. Clinical Applications of 3-D Conformal Radiotherapy

    Science.gov (United States)

    Miralbell, Raymond

    Although a significant improvement in cancer cure (i.e. 20% increment) has been obtained in the last 2-3 decades, 30-40% of patients still fail locally after curative radiotherapy. In order to improve local tumor control rates with radiotherapy high doses to the tumor volume are frequently necessary. Three-dimensional conformal radiation therapy (3-D CRT) is used to denote a spectrum of radiation planning and delivery techniques that rely on three-dimensional imaging to define the target (tumor) and to distinguish it from normal tissues. Modern, high-precision radiotherapy (RT) techniques are needed in order to implement the goal of optimal tumor destruction delivering minimal dose to the non-target normal tissues. A better target definition is nowadays possible with contemporary imaging (computerized tomography, magnetic resonance imaging, and positron emission tomography) and image registration technology. A highly precise dose distributions can be obtained with optimal 3-D CRT treatment delivery techniques such as stereotactic RT, intensity modulated RT (IMRT), or protontherapy (the latter allowing for in-depth conformation). Patient daily set-up repositioning and internal organ immobilization systems are necessary before considering to undertake any of the above mentioned high-precision treatment approaches. Prostate cancer, brain tumors, and base of skull malignancies are among the sites most benefitting of dose escalation approaches. Nevertheless, a significant dose reduction to the normal tissues in the vicinity of the irradiated tumor also achievable with optimal 3-D CRT may also be a major issue in the treatment of pediatric tumors in order to preserve growth, normal development, and to reduce the risk of developing radiation induced diseases such as cancer or endocrinologic disorders.

  8. CT-image-based conformal brachytherapy of breast cancer. The significance of semi-3-D and 3-D treatment planning.

    Science.gov (United States)

    Polgár, C; Major, T; Somogyi, A; Takácsi-Nagy, Z; Mangel, L C; Forrai, G; Sulyok, Z; Fodor, J; Németh, G

    2000-03-01

    To compare the conventional 2-D, the simulator-guided semi-3-D and the recently developed CT-guided 3-D brachytherapy treatment planning in the interstitial radiotherapy of breast cancer. In 103 patients with T1-2, N0-1 breast cancer the tumor bed was clipped during breast conserving surgery. Fifty-two of them received boost brachytherapy after 46 to 50 Gy teletherapy and 51 patients were treated with brachytherapy alone via flexible implant tubes. Single, double and triple plane implant was used in 6, 89 and 8 cases, respectively. The dose of boost brachytherapy and sole brachytherapy prescribed to dose reference points was 3 times 4.75 Gy and 7 times 5.2 Gy, respectively. The positions of dose reference points varied according to the level (2-D, semi-3-D and 3-D) of treatment planning performed. The treatment planning was based on the 3-D reconstruction of the surgical clips, implant tubes and skin points. In all cases the implantations were planned with a semi-3-D technique aided by simulator. In 10 cases a recently developed CT-guided 3-D planning system was used. The semi-3-D and 3-D treatment plans were compared to hypothetical 2-D plans using dose-volume histograms and dose non-uniformity ratios. The values of mean central dose, mean skin dose, minimal clip dose, proportion of underdosaged clips and mean target surface dose were evaluated. The accuracy of tumor bed localization and the conformity of planning target volume and treated volume were also analyzed in each technique. With the help of conformal semi-3-D and 3-D brachytherapy planning we could define reference dose points, active source positions and dwell times individually. This technique decreased the mean skin dose with 22.2% and reduced the possibility of geographical miss. We could achieve the best conformity between the planning target volume and the treated volume with the CT-image based 3-D treatment planning, at the cost of worse dose homogeneity. The mean treated volume was reduced by 25

  9. Conformal field theory in conformal space

    International Nuclear Information System (INIS)

    Preitschopf, C.R.; Vasiliev, M.A.

    1999-01-01

    We present a new framework for a Lagrangian description of conformal field theories in various dimensions based on a local version of d + 2-dimensional conformal space. The results include a true gauge theory of conformal gravity in d = (1, 3) and any standard matter coupled to it. An important feature is the automatic derivation of the conformal gravity constraints, which are necessary for the analysis of the matter systems

  10. Comparative evaluation of two dose optimization methods for image-guided, highly-conformal, tandem and ovoids cervix brachytherapy planning

    Science.gov (United States)

    Ren, Jiyun; Menon, Geetha; Sloboda, Ron

    2013-04-01

    Although the Manchester system is still extensively used to prescribe dose in brachytherapy (BT) for locally advanced cervix cancer, many radiation oncology centers are transitioning to 3D image-guided BT, owing to the excellent anatomy definition offered by modern imaging modalities. As automatic dose optimization is highly desirable for 3D image-based BT, this study comparatively evaluates the performance of two optimization methods used in BT treatment planning—Nelder-Mead simplex (NMS) and simulated annealing (SA)—for a cervix BT computer simulation model incorporating a Manchester-style applicator. Eight model cases were constructed based on anatomical structure data (for high risk-clinical target volume (HR-CTV), bladder, rectum and sigmoid) obtained from measurements on fused MR-CT images for BT patients. D90 and V100 for HR-CTV, D2cc for organs at risk (OARs), dose to point A, conformation index and the sum of dwell times within the tandem and ovoids were calculated for optimized treatment plans designed to treat the HR-CTV in a highly conformal manner. Compared to the NMS algorithm, SA was found to be superior as it could perform optimization starting from a range of initial dwell times, while the performance of NMS was strongly dependent on their initial choice. SA-optimized plans also exhibited lower D2cc to OARs, especially the bladder and sigmoid, and reduced tandem dwell times. For cases with smaller HR-CTV having good separation from adjoining OARs, multiple SA-optimized solutions were found which differed markedly from each other and were associated with different choices for initial dwell times. Finally and importantly, the SA method yielded plans with lower dwell time variability compared with the NMS method.

  11. Conformal radiotherapy: principles and classification

    International Nuclear Information System (INIS)

    Rosenwald, J.C.; Gaboriaud, G.; Pontvert, D.

    1999-01-01

    'Conformal radiotherapy' is the name fixed by usage and given to a new form of radiotherapy resulting from the technological improvements observed during the last ten years. While this terminology is now widely used, no precise definition can be found in the literature. Conformal radiotherapy refers to an approach in which the dose distribution is more closely 'conformed' or adapted to the actual shape of the target volume. However, the achievement of a consensus on a more specific definition is hampered by various difficulties, namely in characterizing the degree of 'conformality'. We have therefore suggested a classification scheme be established on the basis of the tools and the procedures actually used for all steps of the process, i.e., from prescription to treatment completion. Our classification consists of four levels: schematically, at level 0, there is no conformation (rectangular fields); at level 1, a simple conformation takes place, on the basis of conventional 2D imaging; at level 2, a 3D reconstruction of the structures is used for a more accurate conformation; and level 3 includes research and advanced dynamic techniques. We have used our personal experience, contacts with colleagues and data from the literature to analyze all the steps of the planning process, and to define the tools and procedures relevant to a given level. The corresponding tables have been discussed and approved at the European level within the Dynarad concerted action. It is proposed that the term 'conformal radiotherapy' be restricted to procedures where all steps are at least at level 2. (author)

  12. Comparison between conventional and three-dimensional conformal treatment planning for radiotherapy of cerebral tumors

    International Nuclear Information System (INIS)

    Caudrelier, J.M.; Auliard, A.; Sarrazin, T.; Gibon, D.; Coche-Dequeant, B.; Castelain, B.

    2001-01-01

    Comparison between conventional and three-dimensional conformal treatment planning for radiotherapy of cerebral tumors. Purpose. - We prospectively compared a conventional treatment planning (PT2D) and 3-dimensional conformal treatment planning (PT3D) for radiotherapy of cerebral tumours. Patients and methods.- Patients treated between 1/10/98 and 1/4/99 by irradiation for cerebral tumours were analysed. For each case, we planned PT2D using conventional orthogonal x-ray films, and afterward, PT3D using CT scan. Gross tumor volume, planning target volume and normal tissue volumes were defined. Dose was prescribed according to report 50 of the International Commission on Radiation Units and Measurements (ICRU). We compared surfaces of sagittal view targets defined on PT2D and PT3D and called them S2D and S3D, respectively. Irradiated volumes by 90% isodoses (VE-90%) and normal tissue volumes irradiated by 20, 50, 90% isodoses were calculated and compared using Student's paired t-test. Results. -There was a concordance of 84% of target surfaces defined on PT2D and PT3D. Percentages of target surface under- or-over defined by PT2D were 16 and 13% respectively. VE-90% was decreased by 15% (p = 0.07) with PT3D. Normal brain volume irradiated by 90% isodose was decreased by 27% with PT3D (p = 0.04). Conclusion.- For radiotherapy of cerebral tumors using only coplanar beams, PT3D leads to a reduction of normal brain tissue irradiated. We recommend PT3D for radiotherapy of cerebral tumors, particularly for low-grade or benign tumors (meningiomas, neuromas, etc.). (authors)

  13. Inversion theory and conformal mapping

    CERN Document Server

    Blair, David E

    2000-01-01

    It is rarely taught in an undergraduate or even graduate curriculum that the only conformal maps in Euclidean space of dimension greater than two are those generated by similarities and inversions in spheres. This is in stark contrast to the wealth of conformal maps in the plane. The principal aim of this text is to give a treatment of this paucity of conformal maps in higher dimensions. The exposition includes both an analytic proof in general dimension and a differential-geometric proof in dimension three. For completeness, enough complex analysis is developed to prove the abundance of conformal maps in the plane. In addition, the book develops inversion theory as a subject, along with the auxiliary theme of circle-preserving maps. A particular feature is the inclusion of a paper by Carath�odory with the remarkable result that any circle-preserving transformation is necessarily a M�bius transformation, not even the continuity of the transformation is assumed. The text is at the level of advanced undergr...

  14. Three-dimensional conformal radiation therapy: the tomo-therapy approach

    International Nuclear Information System (INIS)

    Linthout, N.; Verellen, D.; Coninck, P. de; Bel, A.; Storme, G.

    2000-01-01

    Conformal radiation therapy allows the possibility of delivering high doses at the tumor volume whilst limiting the dose to the surrounding tissues and diminishing the secondary effects. With the example of the conformal radiation therapy used at the AZ VU8 (3DCRT and tomo-therapy), two treatment plans of a left ethmoid carcinoma will be evaluated and discussed in detail. The treatment of ethmoid cancer is technically difficult for both radiation therapy and surgery because of the anatomic constraints and patterns of local spread. A radiation therapy is scheduled to be delivered after surgical resection of the tumor. The treatment plan for the radiation therapy was calculated on a three-dimensional (3D) treatment planning system based on virtual simulation with a beam's eye view: George Sherouse's Gratis. An effort was made to make the plan as conformal and as homogeneous as possible to deliver a dose of 66 Gy in 33 fractions at the tumor bed with a maximum dose of 56 Gy to the right optic nerve and the chiasma. To establish the clinical utility and potential advantages of tomo-therapy over 3DCRT for ethmoid carcinoma, the treatment of this patient was also planned with Peacock Plant. For both treatment plans the isodose distributions and cumulative dose volume histograms (CDVH) were computed. Superimposing the CDVHs yielded similar curves for the target and an obvious improvement for organs at risk such as the chiasma, brainstem and the left eye when applying tomo-therapy. These results have also been reflected in the tumor control probabilities (equal for both plans) and the normal tissue complication probabilities (NTCP), yielding significant reductions in NTCP for tomo-therapy. The probability of uncomplicated tumor control was 52.7% for tomo-therapy against 38.3% for 3DCRT. (authors)

  15. Extracranial stereotactic radiotherapy: Evaluation of PTV coverage and dose conformity

    International Nuclear Information System (INIS)

    Haedinger, U.; Thiele, W.; Wulf, J.

    2002-01-01

    During the past few years the concept of cranial sterotactic radiotherapy has been successfully extended to extracranial tumoral targets. In our department, hypofractionated treatment of tumours in lung, liver, abdomen, and pelvis is performed in the Stereotactic Body Frame (ELEKTA Instrument AB) since 1997. We present the evaluation of 63 consecutively treated targets (22 lung, 21 liver, 20 abdomen/pelvis) in 58 patients with respect to dose coverage of the planning target volume (PTV) as well as conformity of the dose distribution. The mean PTV coverage was found to be 96.3%±2.3% (lung), 95.0%±4.5% (liver), and 92.1%±5.2% (abdomen/pelvis). For the so-called conformation number we obtained values of 0.73±0.09 (lung), 0.77±0.10 (liver), and 0.70±0.08 (abdomen/pelvis). The results show that highly conformal treatment techniques can be applied also in extracranial stereotactic radiotherapy. This is primarily due to the relatively simple geometrical shape of most of the targets. Especially lung and liver targets turned out to be approximately spherically/cylindrically shaped, so that the dose distribution can be easily tailored by rotational fields. (orig.) [de

  16. SU-E-T-346: Effect of Jaw Position On Dose to Critical Structures in 3-D Conformal Radiotherapy Treatment of Pancreatic Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Paudel, N; Han, E; Liang, X; Morrill, S; Zhang, X; Hardee, M; Penagaricano, J; Ratanatharathorn, V [Vaneerat, University of Arkansas for Medical Sciences, Little Rock, AR (United States)

    2015-06-15

    Purpose: Three-dimensional conformal therapy remains a valid and widely used modality for pancreatic radiotherapy treatment. It usually meets dose constraints on critical structures. However, careful positioning of collimation jaws can reduce dose to the critical structures. Here we investigate the dosimetric effect of jaw position in MLC-based 3-D conformal treatment planning on critical structures. Methods: We retrospectively selected seven pancreatic cancer patients treated with 3-D conformal radiotherapy. We started with treatment plans (Varian Truebeam LINAC, Eclipse TPS, AAA, 18MV) having both x and y jaws aligned with the farthest extent of the block outline (8mm around PTV). Then we subsequently moved either both x-jaws or all x and y jaws outwards upto 3 cm in 1 cm increments and investigated their effect on average and maximum dose to neighboring critical structures keeping the same coverage to treatment volume. Results: Lateral displacement of both x-jaws by 1cm each increased kidney and spleen mean dose by as much as 1.7% and 1.3% respectively and superior inferior displacement increased liver, right kidney, stomach and spleen dose by as much as 2.1%, 2%, 5.2% and 1.6% respectively. Displacement of all x and y-jaws away by 1cm increased the mean dose to liver, right kidney, left kidney, bowels, cord, stomach and spleen by as much as 4.9%, 5.9%, 2.1%, 2.8%, 7.4%, 10.4% and 4.2% respectively. Percentage increase in mean dose due to 2 and 3cm jaw displacement increased almost linearly with the displaced distance. Changes in maximum dose were much smaller (mostly negligible) than the changes in mean dose. Conclusion: Collimation jaw position affects dose mostly to critical structures adjacent to it. Though treatment plans with MLCs conforming the block margin usually meet dose constraints to critical structures, keeping jaws all the way in, to the edge of the block reduces dose to the critical structures during radiation treatment.

  17. Localized field conformation radiotherapy combined with endocrine therapy for the treatment of prostate cancer

    International Nuclear Information System (INIS)

    Karasawa, Katsuyuki; Kaizu, Toshihide; Kurosaki, Hiromasa; Tanaka, Yoshiaki

    1999-01-01

    To improve the quality of life (QOL) of the patients with prostate cancer, we limit the radiotherapy target volume to the prostate and seminal vesicles while using endocrine therapy towards the disease outside the target volume. Radiotherapy technique was rotation conformation technique with computer-controlled multileaf collimators to the total doses of up to 66-70 Gy. Among 145 evaluable cases with the median age of 74, overall and cause-specific 5-year survival rates were 59.3% and 84.1%, respectively, and the relative survival rate of the Stage A-C cases was 100%. The two thirds (33/50) of the deaths were not of prostate cancer. The rate of severe complication was 1.4%. As for QOL, the rate of impotence was 90%, however, the patients' overall satisfaction towards the treatment was 90%. From this analysis, this combined treatment seems beneficial in the treatment of prostate cancer. (author)

  18. Beam shaping for conformal fractionated stereotactic radiotherapy: a modeling study

    International Nuclear Information System (INIS)

    Hacker, Fred L.; Kooy, Hanne M.; Bellerive, Marc R.; Killoran, Joseph H.; Leber, Zachary H.; Shrieve, Dennis C.; Tarbell, Nancy J.; Loeffler, Jay S.

    1997-01-01

    Purpose: The patient population treated with fractionated stereotactic radiotherapy (SRT) is significantly different than that treated with stereotactic radiosurgery (SRS). Generally, lesions treated with SRT are larger, less spherical, and located within critical regions of the central nervous system; hence, they offer new challenges to the treatment planner. Here a simple, cost effective, beam shaping system has been evaluated relative to both circular collimators and an ideal dynamically conforming system for effectiveness in providing conformal therapy for these lesions. Methods and Materials: We have modeled a simple system for conformal arc therapy using four independent jaws. The jaw positions and collimator angle are changed between arcs but held fixed for the duration of each arc. Eleven previously treated SRT cases have been replanned using this system. The rectangular jaw plans were then compared to the original treatment plans which used circular collimators. The plans were evaluated with respect to tissue sparing at 100%, 80%, 50%, and 20% of the prescription dose. A plan was also done for each tumor in which the beam aperture was continuously conformed to the beams eye view projection of the tumor. This was used as an ideal standard for conformal therapy in the absence of fluence modulation. Results: For tumors with a maximum extent of over 3.5 cm the rectangular jaw plans reduced the mean volume of healthy tissue involved at the prescription dose by 57% relative to the circular collimator plans. The ideal conformal plans offered no significant further improvement at the prescription dose. The relative advantage of the rectangular jaw plans decreased at lower isodoses so that at 20% of the prescription dose tissue involvement for the rectangular jaw plans was equivalent to that for the circular collimator plans. At these isodoses the ideal conformal plans gave substantially better tissue sparing. Conclusion: A simple and economical field shaping

  19. Assessing the quality of conformal treatment planning: a new tool for quantitative comparison

    International Nuclear Information System (INIS)

    Menhel, J; Levin, D; Alezra, D; Symon, Z; Pfeffer, R

    2006-01-01

    We develop a novel radiotherapy plan comparison index, critical organ scoring index (COSI), which is a measure of both target coverage and critical organ overdose. COSI is defined as COSI = 1 - (V(OAR) >tol /TC), where V(OAR) >tol is the fraction of volume of organ at risk receiving more than tolerance dose, and TC is the target coverage, V T,PI /V T , where V T,PI is the target volume receiving at a least prescription dose and V T is the total target volume. COSI approaches unity when the critical structure is completely spared and the target coverage is unity. We propose a two-dimensional, graphical representation of COSI versus conformity index (CI), where CI is a measure of a normal tissue overdose. We show that this 2D representation is a reliable, visual quantitative tool for evaluating competing plans. We generate COSI-CI plots for three sites: head and neck, cavernous sinus, and pancreas, and evaluate competing non-coplanar 3D and IMRT treatment plans. For all three sites this novel 2D representation assisted the physician in choosing the optimal plan, both in terms of target coverage and in terms of critical organ sparing. We verified each choice by analysing individual DVHs and isodose lines. Comparing our results to the widely used conformation number, we found that in all cases where there were discrepancies in the choice of the best treatment plan, the COSI-CI choice was considered the correct one, in several cases indicating that a non-coplanar 3D plan was superior to the IMRT plans. The choice of plan was quick, simple and accurate using the new graphical representation

  20. Bladder radiotherapy treatment: A retrospective comparison of 3-dimensional conformal radiotherapy, intensity-modulated radiation therapy, and volumetric-modulated arc therapy plans

    Energy Technology Data Exchange (ETDEWEB)

    Pasciuti, Katia, E-mail: k.pasciuti@virgilio.it [Department of Radiotherapy Physics, Royal Free Hospital, London (United Kingdom); Kuthpady, Shrinivas [Department of Radiotherapy, Royal Free Hospital, London (United Kingdom); Anderson, Anne; Best, Bronagh [Department of Radiotherapy Physics, Royal Free Hospital, London (United Kingdom); Waqar, Saleem; Chowdhury, Subhra [Department of Radiotherapy, Royal Free Hospital, London (United Kingdom)

    2017-04-01

    To examine tumor's and organ's response when different radiotherapy plan techniques are used. Ten patients with confirmed bladder tumors were first treated using 3-dimensional conformal radiotherapy (3DCRT) and subsequently the original plans were re-optimized using the intensity-modulated radiation treatment (IMRT) and volumetric-modulated arc therapy (VMAT)-techniques. Targets coverage in terms of conformity and homogeneity index, TCP, and organs' dose limits, including integral dose analysis were evaluated. In addition, MUs and treatment delivery times were compared. Better minimum target coverage (1.3%) was observed in VMAT plans when compared to 3DCRT and IMRT ones confirmed by a statistically significant conformity index (CI) results. Large differences were observed among techniques in integral dose results of the femoral heads. Even if no statistically significant differences were reported in rectum and tissue, a large amount of energy deposition was observed in 3DCRT plans. In any case, VMAT plans provided better organs and tissue sparing confirmed also by the normal tissue complication probability (NTCP) analysis as well as a better tumor control probability (TCP) result. Our analysis showed better overall results in planning using VMAT techniques. Furthermore, a total time reduction in treatment observed among techniques including gantry and collimator rotation could encourage using the more recent one, reducing target movements and patient discomfort.

  1. Quantifying polypeptide conformational space: sensitivity to conformation and ensemble definition.

    Science.gov (United States)

    Sullivan, David C; Lim, Carmay

    2006-08-24

    Quantifying the density of conformations over phase space (the conformational distribution) is needed to model important macromolecular processes such as protein folding. In this work, we quantify the conformational distribution for a simple polypeptide (N-mer polyalanine) using the cumulative distribution function (CDF), which gives the probability that two randomly selected conformations are separated by less than a "conformational" distance and whose inverse gives conformation counts as a function of conformational radius. An important finding is that the conformation counts obtained by the CDF inverse depend critically on the assignment of a conformation's distance span and the ensemble (e.g., unfolded state model): varying ensemble and conformation definition (1 --> 2 A) varies the CDF-based conformation counts for Ala(50) from 10(11) to 10(69). In particular, relatively short molecular dynamics (MD) relaxation of Ala(50)'s random-walk ensemble reduces the number of conformers from 10(55) to 10(14) (using a 1 A root-mean-square-deviation radius conformation definition) pointing to potential disconnections in comparing the results from simplified models of unfolded proteins with those from all-atom MD simulations. Explicit waters are found to roughen the landscape considerably. Under some common conformation definitions, the results herein provide (i) an upper limit to the number of accessible conformations that compose unfolded states of proteins, (ii) the optimal clustering radius/conformation radius for counting conformations for a given energy and solvent model, (iii) a means of comparing various studies, and (iv) an assessment of the applicability of random search in protein folding.

  2. A note on fashion cycles, novelty and conformity

    OpenAIRE

    Federica Alberti

    2013-01-01

    We develop a model in which novelty and conformity motivate fashion behavior. Fashion cycles occur if conformity is not too high. The duration of fashion cycles depends on individual-specific conformity, novelty, and the number of available styles. The use of individual-specific novelty and conformity allows us to also identify fashion leaders.

  3. Workers’ Conformism

    Directory of Open Access Journals (Sweden)

    Nikolay Ivantchev

    2013-10-01

    Full Text Available Conformism was studied among 46 workers with different kinds of occupations by means of two modified scales measuring conformity by Santor, Messervey, and Kusumakar (2000 – scale for perceived peer pressure and scale for conformism in antisocial situations. The hypothesis of the study that workers’ conformism is expressed in a medium degree was confirmed partly. More than a half of the workers conform in a medium degree for taking risk, and for the use of alcohol and drugs, and for sexual relationships. More than a half of the respondents conform in a small degree for anti-social activities (like a theft. The workers were more inclined to conform for risk taking (10.9%, then – for the use of alcohol, drugs and for sexual relationships (8.7%, and in the lowest degree – for anti-social activities (6.5%. The workers who were inclined for the use of alcohol and drugs tended also to conform for anti-social activities.

  4. Efficient free energy calculations for compounds with multiple stable conformations separated by high energy barriers

    NARCIS (Netherlands)

    Hritz, J.; Oostenbrink, C.

    2009-01-01

    Compounds with high intramolecular energy barriers represent challenging targets for free energy calculations because of the difficulty to obtain sufficient conformational sampling. Existing approaches are therefore computationally very demanding, thus preventing practical applications for such

  5. Three-dimensional treatment planning for postoperative radiotherapy in patients with node-positive cervical cancer. Comparison between a conventional and a conformal technique

    Energy Technology Data Exchange (ETDEWEB)

    Olofsen-van Acht, M.J.J.; Quint, S.; Seven, M.; Berg, H.A. van den; Levendag, P.C. [University Hospital Rotterdam (Netherlands). Dept. of Radiation Oncology; Santvoort, J.P.C. van [University Hospital Rotterdam (Netherlands). Subdivision of Clinical Physics; Logmans, A. [University Hospital Rotterdam (Netherlands). Dept. of Gynecologic Oncology

    1999-09-01

    Purpose: Reduction of irradiated small bowel volume, using a conformal three-dimensional treatment planning technique in postoperative radiotherapy of cervical cancer patients. Patients and Methods: Large gynecological treatment fields including the para-aortic nodes were analyzed in 15 patients. A conventional treatment plan with anterior and posterior (AP-PA) parallel opposed fields and a 3D 4-field conformal radiotherapy plan with a central blocking of small bowel were compared for each patient. Dose-volume histograms and dose parameters were established. Because of the tolerance constraints of the small bowel, the cumulative dose applied to the target was 48.6 Gy. Results: The mean Tumor Control Probability (TCP) values for both the conventional and the conformal technique were 0.60 and 0.61, respectively, with ranges of 0.56 to 0.67 and 0.57 to 0.66, respectively. The mean volume receiving 95% or more of the prescribed dose (V95) of the small bowel was 47.6% (32.5 to 66.3%) in the AP-PA technique and 14.9% (7.0 to 22.5%) in the conformal technique (p<0.001), indicating a significant reduction in irradiated volume of small bowel in the higher dose range. The mean Normal Tissue Complication Probability (NTCP) decreased from 0.11 to 0.03 with the conformal plan. In patients who received a pedicled omentoplasty during surgery, the mean V95 for small bowel could be reduced to 8.5% (7.0 to 9.9%). The mean median dose to the kidneys was only slightly elevated in the conformal treatment. Especially the mean dose to the right kidney in conventional vs conformal treatment was 3.3 vs 7.9 Gy. The mean near-minimum dose (D95) to the rectosigmoid decreased from 48.4 to 30.1 Gy in the conformal plan compared to the conventional plan. Conclusion: The small bowel dose can be significantly reduced with 3D treatment planning, particularly if a predicled omentoplasty is performed. This allows dose escalation to the tumor region without unacceptable toxicity for the small bowel

  6. Killing tensors and conformal Killing tensors from conformal Killing vectors

    International Nuclear Information System (INIS)

    Rani, Raffaele; Edgar, S Brian; Barnes, Alan

    2003-01-01

    Koutras has proposed some methods to construct reducible proper conformal Killing tensors and Killing tensors (which are, in general, irreducible) when a pair of orthogonal conformal Killing vectors exist in a given space. We give the completely general result demonstrating that this severe restriction of orthogonality is unnecessary. In addition, we correct and extend some results concerning Killing tensors constructed from a single conformal Killing vector. A number of examples demonstrate that it is possible to construct a much larger class of reducible proper conformal Killing tensors and Killing tensors than permitted by the Koutras algorithms. In particular, by showing that all conformal Killing tensors are reducible in conformally flat spaces, we have a method of constructing all conformal Killing tensors, and hence all the Killing tensors (which will in general be irreducible) of conformally flat spaces using their conformal Killing vectors

  7. A Dualistic Conformational Response to Substrate Binding in the Human Serotonin Transporter Reveals a High Affinity State for Serotonin*

    Science.gov (United States)

    Bjerregaard, Henriette; Severinsen, Kasper; Said, Saida; Wiborg, Ove; Sinning, Steffen

    2015-01-01

    Serotonergic neurotransmission is modulated by the membrane-embedded serotonin transporter (SERT). SERT mediates the reuptake of serotonin into the presynaptic neurons. Conformational changes in SERT occur upon binding of ions and substrate and are crucial for translocation of serotonin across the membrane. Our understanding of these conformational changes is mainly based on crystal structures of a bacterial homolog in various conformations, derived homology models of eukaryotic neurotransmitter transporters, and substituted cysteine accessibility method of SERT. However, the dynamic changes that occur in the human SERT upon binding of ions, the translocation of substrate, and the role of cholesterol in this interplay are not fully elucidated. Here we show that serotonin induces a dualistic conformational response in SERT. We exploited the substituted cysteine scanning method under conditions that were sensitized to detect a more outward-facing conformation of SERT. We found a novel high affinity outward-facing conformational state of the human SERT induced by serotonin. The ionic requirements for this new conformational response to serotonin mirror the ionic requirements for translocation. Furthermore, we found that membrane cholesterol plays a role in the dualistic conformational response in SERT induced by serotonin. Our results indicate the existence of a subpopulation of SERT responding differently to serotonin binding than hitherto believed and that membrane cholesterol plays a role in this subpopulation of SERT. PMID:25614630

  8. Conformational dynamics data bank: a database for conformational dynamics of proteins and supramolecular protein assemblies.

    Science.gov (United States)

    Kim, Do-Nyun; Altschuler, Josiah; Strong, Campbell; McGill, Gaël; Bathe, Mark

    2011-01-01

    The conformational dynamics data bank (CDDB, http://www.cdyn.org) is a database that aims to provide comprehensive results on the conformational dynamics of high molecular weight proteins and protein assemblies. Analysis is performed using a recently introduced coarse-grained computational approach that is applied to the majority of structures present in the electron microscopy data bank (EMDB). Results include equilibrium thermal fluctuations and elastic strain energy distributions that identify rigid versus flexible protein domains generally, as well as those associated with specific functional transitions, and correlations in molecular motions that identify molecular regions that are highly coupled dynamically, with implications for allosteric mechanisms. A practical web-based search interface enables users to easily collect conformational dynamics data in various formats. The data bank is maintained and updated automatically to include conformational dynamics results for new structural entries as they become available in the EMDB. The CDDB complements static structural information to facilitate the investigation and interpretation of the biological function of proteins and protein assemblies essential to cell function.

  9. Hi-C 2.0: An optimized Hi-C procedure for high-resolution genome-wide mapping of chromosome conformation.

    Science.gov (United States)

    Belaghzal, Houda; Dekker, Job; Gibcus, Johan H

    2017-07-01

    Chromosome conformation capture-based methods such as Hi-C have become mainstream techniques for the study of the 3D organization of genomes. These methods convert chromatin interactions reflecting topological chromatin structures into digital information (counts of pair-wise interactions). Here, we describe an updated protocol for Hi-C (Hi-C 2.0) that integrates recent improvements into a single protocol for efficient and high-resolution capture of chromatin interactions. This protocol combines chromatin digestion and frequently cutting enzymes to obtain kilobase (kb) resolution. It also includes steps to reduce random ligation and the generation of uninformative molecules, such as unligated ends, to improve the amount of valid intra-chromosomal read pairs. This protocol allows for obtaining information on conformational structures such as compartment and topologically associating domains, as well as high-resolution conformational features such as DNA loops. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. A treatment planning comparison of two different 3D conformal techniques for irradiation of head and neck cancer patients

    International Nuclear Information System (INIS)

    Krstevska, Valentina; Lukarski, Dusko; Petkovska, Sonja

    2010-01-01

    The purpose of this treatment planning study was to compare two different three dimensional conformal irradiation techniques for head and neck cancer patients. For 33 patients with head and neck carcinoma, irradiated according to the classical technique, we computed and evaluated a second irradiation technique in order to optimize the treatment planning protocol. The classical technique, termed 'electron-photon fields', employed two lateral semi-fields (23 fractions) for irradiation of the upper part of the planning target volume that should receive 50 Gy (PTV50) and an anterior and posterior field for the lower part. After the 23rd fraction the lateral fields were reduced from the dorsal side (2 fractions), in order to exclude the spinal cord from them. At the same time the dose to the shielded part of the target volume was delivered with matched electron fields. Finally, after the 25th fraction, the high risk volume was irradiated to the desired dose with plan where the spinal cord was completely shielded. In the new technique, termed 'oblique photon fields', 4 oblique isocentric photon fields were used (25 fractions): two anterior fields that covered the entire target volume that should receive 50 Gy and two posterior fields that covered only half of the target volume in order to shield the spinal cord. Thus, the necessity for using electron fields is eliminated. We kept the plan for irradiation of the high risk planning target volume the same as in the classical technique. The prescribed dose per fraction in all plans was 2 Gy. In both techniques the plans were optimized to the same maximal point dose and the same dose to the spinal cord. The oblique fields plan showed better coverage and homogeneity of the PTV50, except for the patients with positive resection margins receiving postoperative radiotherapy (receiving 66 Gy), where the coverage did not differ significantly. The conformity in both techniques did not differ significantly. The mean dose to the

  11. 13CHD2–CEST NMR spectroscopy provides an avenue for studies of conformational exchange in high molecular weight proteins

    International Nuclear Information System (INIS)

    Rennella, Enrico; Huang, Rui; Velyvis, Algirdas; Kay, Lewis E.

    2015-01-01

    An NMR experiment for quantifying slow (millisecond) time-scale exchange processes involving the interconversion between visible ground state and invisible, conformationally excited state conformers is presented. The approach exploits chemical exchange saturation transfer (CEST) and makes use of 13 CHD 2 methyl group probes that can be readily incorporated into otherwise highly deuterated proteins. The methodology is validated with an application to a G48A Fyn SH3 domain that exchanges between a folded conformation and a sparsely populated and transiently formed unfolded ensemble. Experiments on a number of different protein systems, including a 360 kDa half-proteasome, establish that the sensitivity of this 13 CHD 2 13 C–CEST technique can be upwards of a factor of 5 times higher than for a previously published 13 CH 3 13 C–CEST approach (Bouvignies and Kay in J Biomol NMR 53:303–310, 2012), suggesting that the methodology will be powerful for studies of conformational exchange in high molecular weight proteins

  12. Ultrasound-guided high dose rate conformal brachytherapy boost in prostate cancer: treatment description and preliminary results of a phase I/II clinical trial

    Energy Technology Data Exchange (ETDEWEB)

    Stromberg, Jannifer; Martinez, Alvaro; Gonzalez, Jose; Edmundson, Gregory; Ohanian, Neshan; Vicini, Frank; Hollander, Jay; Gustafson, Gary; Spencer, William; Di, Yan; Brabbins, Donald

    1995-08-30

    Purpose: To improve results for locally advanced prostate cancer, a prospective clinical trial of concurrent external beam irradiation and fractionated iridium-192 (Ir-192) high dose rate (HDR) conformal boost brachytherapy was initiated. Methods and Materials: Between November 1991 and February 1994, 99 implants were performed on 33 patients with prostatic adenocarcinoma at William Beaumont Hospital. Using AJCC staging criteria, 9 patients had T2b tumors, 17 patients had T2c tumors, and 7 patients had T3 disease. Patients were treated with (a) 45.6 Gy whole pelvis external irradiation and (b) three HDR fractions of 5.5 Gy each (18 patients) or 6 Gy each (15 patients) to the prostate. Transperineal needle implants using real-time ultrasound guidance with interactive on-line isodose distributions were performed on an outpatient basis during weeks 1, 2, and 3 of external irradiation. Acute toxicity was scored using the Radiation Therapy Oncology Group (RTOG) morbidity grading system. Results: This technique of concurrent external pelvic irradiation and conformal HDR brachytherapy was well tolerated. No significant intraoperative or perioperative complications occurred. Three patients (9%) experienced Grade 3 acute toxicity (two dysuria and one diarrhea). All toxicities were otherwise Grades 1 or 2 and were primarily as expected from pelvic external irradiation. Persistent implant-related toxicities included Grades 1-2 perineal pain (12%) and hematospermia (15%). Median follow-up time was 13 months. Serum prostatic-specific antigen (PSA) levels normalized in 91% of patients (29 out of 32) within 1-14 months (median 2.8 months) after irradiation. PSA levels were progressively decreasing in the other three patients at last measurement. Prospectively planned prostatic rebiopsies done at 18 months in the first 10 patients were negative in 9 out of 10 (90%). Conclusions: Acute toxicity has been acceptable with this unique approach using conformal high dose rate Ir-192

  13. Implementation of intensity-modulated conformational radiotherapy for cervical cancers at the Alexis Vautrin Centre

    International Nuclear Information System (INIS)

    Renard-Oldrini, Sophie

    2010-01-01

    As platinum salt based concomitant conformational radiotherapy and chemotherapy have been used as a standard treatment for cervical cancers but resulted in digestive and haematological toxicities, this research thesis reports the application of intensity-modulated conformational radiation therapy. After having recalled some epidemiological, anatomical aspects, diagnosis and treatments aspects regarding cervical cancer, the author presents this last treatment technique (principles, benefits, practical implementation). The author discusses results obtained by an experiment during which seven patients have been treated by simple conformational radiation therapy, and four by intensity-modulated conformational radiation therapy. Results are discussed in terms of volumes (clinical target volume, growth target volume, planned target volume), dosimetric results, toxicities (urine and skin), weight loss [fr

  14. An introduction to conformal field theory

    International Nuclear Information System (INIS)

    Gaberdiel, Matthias R.; Fitzwilliam College, Cambridge

    2000-01-01

    A comprehensive introduction to two-dimensional conformal field theory is given. The structure of the meromorphic subtheory is described in detail, and a number of examples are presented explicitly. Standard constructions such as the coset and the orbifold construction are explained. The concept of a representation of the meromorphic theory is introduced, and the role of Zhu's algebra in classifying highest weight representations is elucidated. The fusion product of two representations and the corresponding fusion rules are defined, and Verlinde's formula is explained. Finally, higher correlation functions are considered, and the polynomial relations of Moore and Seiberg and the quantum group structure of chiral conformal field theory are discussed. The treatment is relatively general and also allows for a description of less well known classes of theories such as logarithmic conformal field theories. (author)

  15. CT-image based conformal brachytherapy of breast cancer. The significance of semi-3-D and 3-D treatment planning

    International Nuclear Information System (INIS)

    Polgar, C.; Major, T.; Somogyi, A.; Takacsi-Nagy, Z.; Mangel, L.C.; Fodor, J.; Nemeth, G.; Forrai, G.; Sulyok, Z.

    2000-01-01

    In 103 patients with T1-2, N0-1 breast cancer the tumor bed was clipped during breast conserving surgery. Fifty-two of them received boost brachytherapy after 46 to 50 Gy teletherapy and 51 patients were treated with brachytherapy alone via flexible implant tubes. Single double and triple plane implant was used in 6,89 and 8 cases, respectively. The dose of boost brachytherapy and sole brachytherapy prescribed to dose reference points was 3 times 4.75 Gy and 7 times 5.2 Gy, respectively. The positions of dose reference points varied according to the level (2-D, semi-3-D and 3-D) of treatment planning performed. The treatment planning was based on the 3-D reconstruction of the surgical clips, implant tubes and skin points. In all cases the implantations were planned with a semi-3-D technique aided by simulator. In 10 cases a recently developed CT-guided 3-D planning system was used. The semi-3D and 3-D treatment plans were compared to hypothetical 2-D plans using dose-volume histograms and dose non-uniformity ratios. The values of mean central dose, mean skin dose, minimal clip dose, proportion of underdosaged clips and mean target surface dose were evaluated. The accuracy of tumor bed localization and the conformity of planning target volume and treated volume were also analyzed in each technique. Results: With the help of conformal semi-3D and 3D brachytherapy planning we could define reference dose points, active source positions and dwell times individually. This technique decreased the mean skin dose with 22.2% and reduced the possibility of geographical miss. We could achieve the best conformity between the planning target volume and the treated volume with the CT-image based 3-D treatment planning, at the cost of worse dose homogeneity. The mean treated volume was reduced by 25.1% with semi-3-D planning, however, its was increased by 16.2% with 3-D planning, compared to the 2-D planning. (orig.) [de

  16. Radiotherapy of intensity modulated VS conformational in the treatment of carcinoma of the prostate. A dosimetric comparison; Radioterapia de intensidad modulada VS conformacional en el tratamiento de carcinoma de prostata. Una camparacion dosimetrica

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Martin, G.; Garcia Vicente, F.; Zapatero Laborda, A.; Bermudez Luna, R.; Roch Gonzalez, M.; Perez Gonzalez, L.; Torres Escobar, J. J.

    2013-07-01

    The intensity modulated (IMRT) radiation therapy is a technique of high conformation which, by its nature, has as one of its main directions prostate cancer radiotherapy treatment. The purpose of this work is presents results of the dosimetric indicators collected in our hospital a number of patients of carcinoma of the prostate with standard three-dimensional Conformal technique (3D-CRT) and IMRT. Aims to demonstrate and quantify with a statistical methodology that, establishing an adequate Protocol of IMRT, significant reductions in risk organ doses can be obtained by keeping the same prescription to the white volume. (Author)

  17. Conformity Index and Homogeneity Index of the Postoperative Whole Breast Radiotherapy.

    Science.gov (United States)

    Petrova, Deva; Smickovska, Snezana; Lazarevska, Emilija

    2017-10-15

    The treatment of breast cancer involves a multidisciplinary approach in which radiotherapy plays a key role. The conformity index and the homogeneity index are two analysis tools of a treatment plan using conformal radiotherapy. The purpose of this article is an analysis of these two parameters in the assessment of the treatment plans in 58 patients undergoing postoperative radiotherapy of the whole breast. All 58 patients participating in the study had a conservatively treated early-stage breast cancer. The treatment was performed using a standard regimen of fractionation in 25 fractions up to a total dose of 50 Gy. Dose-volume histograms were generated for both plans with and without segmental fields. Pair samples t-test was used. The technique with segmental fields allowed us more homogeneity distribution when compared to standard two tangential field techniques. The HI values were 1.08 ± 0.01 and 1.09 ± 0.01 for segment and technique with two tangential fields (p conformity and the homogeneity index are important tools in the analysis of the treatment plans during radiation therapy in patients with early-stage breast cancer. Adding segment fields in the administration of radiotherapy in patients with conservatively treated breast cancer can lead to improved dosage homogeneity and conformity.

  18. Dual Drug Targeting of Mutant Bcr-Abl Induces Inactive Conformation: New Strategy for the Treatment of Chronic Myeloid Leukemia and Overcoming Monotherapy Resistance.

    Science.gov (United States)

    El Rashedy, Ahmed A; Olotu, Fisayo A; Soliman, Mahmoud E S

    2018-03-01

    Bcr-Abl is an oncogenic fusion protein which expression enhances tumorigenesis, and has been highly associated with chronic myeloid leukemia (CML). Acquired drug resistance in mutant Bcr-Abl has enhanced pathogenesis with the use of single therapy agents such as nilotinib. Moreover, allosteric targeting has been identified to consequentially inhibit Bcr-Abl activity, which led to the recent development of ABL-001 (asciminib) that selectively binds the myristoyl pocket. Experimental studies have revealed that the combination of nilotinib and ABL-001 induced a 'bent' conformation in the C-terminal helix of Bcr-Abl; a benchmark of inhibition, thereby exhibiting a greater potency in the treatment of CML, surmounting the setbacks of drug resistance, disease regression and relapse. Therefore, we report the first account of the dynamics and conformational analysis of oncogenic T334I Bcr-Abl by dual targeting. Our findings revealed that unlike in the Bcr-Abl-Nilotinib complex, dual targeting by both inhibitors induced the bent conformation in the C-terminal helix that varied with time. This was coupled with significant alteration in Bcr-Abl stability, flexibility, and compactness and an overall structural re-orientation inwards towards the hydrophobic core, which reduced the solvent-exposed residues indicative of protein folding. This study will facilitate allosteric targeting and the design of more potent allosteric inhibitors for resistive target proteins in cancer. © 2018 Wiley-VHCA AG, Zurich, Switzerland.

  19. Could 3-D conformal radiotherapy improve the overall survival for non-small cell lung cancer?

    International Nuclear Information System (INIS)

    Giraud, P.; Helfre, S.; Lavole, A.; Rosenwald, J.C.; Cosset, J.M.

    2002-01-01

    The conformal radiotherapy approach, three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT), is based on modern imaging modalities, efficient 3-D treatment planning systems, sophisticated immobilization devices and demanding quality assurance and treatment verification. The main goal of conformal radiotherapy is to ensure a high dose distribution tailored to the limits of the target volume while reducing exposure of healthy tissues. These techniques would then allow a further dose escalation increasing local control and survival. Non-small cell lung cancer (NSCLC) is one of the most difficult malignant tumors to be treated. It combines geometrical difficulties due to respiratory motion, and number of low tolerance neighboring organs, and dosimetric difficulties because of the presence of huge inhomogeneities. This localization is an attractive and ambitious example for the evaluation of new techniques. However, the published clinical reports in the last years described very heterogeneous techniques and, in the absence of prospective randomized trials, it is somewhat difficult at present to evaluate the real benefits drawn from those conformal radiotherapy techniques. After reviewing the rationale for 3DCRT for NSCLC, this paper will describe the main studies of 3DCRT, in order to evaluate its impact on lung cancer treatment Then the current state-of-the-art of IMRT and the last technical and therapeutic innovations in NSCL will be discussed. (authors)

  20. High-order discrete ordinate transport in non-conforming 2D Cartesian meshes

    International Nuclear Information System (INIS)

    Gastaldo, L.; Le Tellier, R.; Suteau, C.; Fournier, D.; Ruggieri, J. M.

    2009-01-01

    We present in this paper a numerical scheme for solving the time-independent first-order form of the Boltzmann equation in non-conforming 2D Cartesian meshes. The flux solution technique used here is the discrete ordinate method and the spatial discretization is based on discontinuous finite elements. In order to have p-refinement capability, we have chosen a hierarchical polynomial basis based on Legendre polynomials. The h-refinement capability is also available and the element interface treatment has been simplified by the use of special functions decomposed over the mesh entities of an element. The comparison to a classical S N method using the Diamond Differencing scheme as spatial approximation confirms the good behaviour of the method. (authors)

  1. Ras conformational switching: simulating nucleotide-dependent conformational transitions with accelerated molecular dynamics.

    Directory of Open Access Journals (Sweden)

    Barry J Grant

    2009-03-01

    Full Text Available Ras mediates signaling pathways controlling cell proliferation and development by cycling between GTP- and GDP-bound active and inactive conformational states. Understanding the complete reaction path of this conformational change and its intermediary structures is critical to understanding Ras signaling. We characterize nucleotide-dependent conformational transition using multiple-barrier-crossing accelerated molecular dynamics (aMD simulations. These transitions, achieved for the first time for wild-type Ras, are impossible to observe with classical molecular dynamics (cMD simulations due to the large energetic barrier between end states. Mapping the reaction path onto a conformer plot describing the distribution of the crystallographic structures enabled identification of highly populated intermediate structures. These structures have unique switch orientations (residues 25-40 and 57-75 intermediate between GTP and GDP states, or distinct loop3 (46-49, loop7 (105-110, and alpha5 C-terminus (159-166 conformations distal from the nucleotide-binding site. In addition, these barrier-crossing trajectories predict novel nucleotide-dependent correlated motions, including correlations of alpha2 (residues 66-74 with alpha3-loop7 (93-110, loop2 (26-37 with loop10 (145-151, and loop3 (46-49 with alpha5 (152-167. The interconversion between newly identified Ras conformations revealed by this study advances our mechanistic understanding of Ras function. In addition, the pattern of correlated motions provides new evidence for a dynamic linkage between the nucleotide-binding site and the membrane interacting C-terminus critical for the signaling function of Ras. Furthermore, normal mode analysis indicates that the dominant collective motion that occurs during nucleotide-dependent conformational exchange, and captured in aMD (but absent in cMD simulations, is a low-frequency motion intrinsic to the structure.

  2. Conformational intermediate of the amyloidogenic protein beta 2-microglobulin at neutral pH

    DEFF Research Database (Denmark)

    Heegaard, N H; Sen, J W; Kaarsholm, N C

    2001-01-01

    electrophoresis that two conformers spontaneously exist in aqueous buffers at neutral pH. Upon treatment of wild-type beta(2)-microglobulin with acetonitrile or trifluoroethanol, two conformations were also observed. These conformations were in equilibrium dependent on the sample temperature and the percentage...

  3. A precision cranial immobilization system for conformal stereotactic fractionated radiation therapy

    International Nuclear Information System (INIS)

    Rosenthal, Stanley J.; Gall, Kenneth P.; Jackson, Matthew; Thornton, Allan F.

    1995-01-01

    Purpose: Conformal radiotherapy has been shown to benefit from precision alignment of patient target to therapy beam (1, 6, 13). This work describes an optimized immobilization system for the fractionated treatment of intracranial targets. A study of patient motion demonstrates the high degree of immobilization which is available. Methods and Materials: A system using dental fixation and a thermoplastic mask that relocates on a rigid frame is described. The design permits scanning studies using computed tomography (CT) and magnetic resonance imaging (MR), conventional photon radiotherapy, and high precision stereotactic proton radiotherapy to be performed with minimal repositioning variation. Studies of both intratreatment motion and daily setup reliability are performed on patients under treatment for paranasal sinus carcinoma. Multiple radiographs taken during single treatments provide the basis for a three-dimensional (3D) motion analysis. Additionally, studies of orthogonal radiographs used to setup for proton treatments and verification port films from photon treatments are used to establish day to day patient position variation in routine use. Results: Net 3D patient motion during any treatment is measured to be 0.9 ± 0.4 mm [mean ± standard deviation (SD)] and rotation about any body axis is 0.14 ± 0.67 degrees (mean ± SD). Day-to-day setup accuracy to laser marks is limited to 2.3 mm (mean) systematic error and 1.6 mm (mean) random error. Conclusion: We conclude that the most stringent immobilization requirements of 3D conformal radiotherapy adjacent to critical normal structures can be met with a high precision system such as the one described here. Without the use of pretreatment verification, additional developments in machine and couch design are needed to assure that patient repositioning accuracy is comparable to the best level of patient immobility achievable

  4. Conformational Clusters of Phosphorylated Tyrosine.

    Science.gov (United States)

    Abdelrasoul, Maha; Ponniah, Komala; Mao, Alice; Warden, Meghan S; Elhefnawy, Wessam; Li, Yaohang; Pascal, Steven M

    2017-12-06

    Tyrosine phosphorylation plays an important role in many cellular and intercellular processes including signal transduction, subcellular localization, and regulation of enzymatic activity. In 1999, Blom et al., using the limited number of protein data bank (PDB) structures available at that time, reported that the side chain structures of phosphorylated tyrosine (pY) are partitioned into two conserved conformational clusters ( Blom, N.; Gammeltoft, S.; Brunak, S. J. Mol. Biol. 1999 , 294 , 1351 - 1362 ). We have used the spectral clustering algorithm to cluster the increasingly growing number of protein structures with pY sites, and have found that the pY residues cluster into three distinct side chain conformations. Two of these pY conformational clusters associate strongly with a narrow range of tyrosine backbone conformation. The novel cluster also highly correlates with the identity of the n + 1 residue, and is strongly associated with a sequential pYpY conformation which places two adjacent pY side chains in a specific relative orientation. Further analysis shows that the three pY clusters are associated with distinct distributions of cognate protein kinases.

  5. Conformal house

    DEFF Research Database (Denmark)

    Ryttov, Thomas Aaby; Sannino, Francesco

    2010-01-01

    fixed point. As a consistency check we recover the previously investigated bounds of the conformal windows when restricting to a single matter representation. The earlier conformal windows can be imagined to be part now of the new conformal house. We predict the nonperturbative anomalous dimensions...... at the infrared fixed points. We further investigate the effects of adding mass terms to the condensates on the conformal house chiral dynamics and construct the simplest instanton induced effective Lagrangian terms...

  6. Head and neck cancers: clinical benefits of three-dimensional conformal radiotherapy and of intensity-modulated radiotherapy

    International Nuclear Information System (INIS)

    Giraud, P.; Jaulerry, C.; Brunin, F.; Zefkili, S.; Helfre, S.; Chauvet, I.; Rosenwald, J.C.; Cosset, J.M.

    2002-01-01

    The conformal radiotherapy approach, three-dimensional conformal radiotherapy (3DCRT) or intensity-modulated radiotherapy (IMRT), is based on modern imaging modalities, efficient 3-D treatment planning systems, sophisticated immobilization systems and rigorous quality assurance and treatment verification. The central objective of conformal radiotherapy is to ensure a high dose distribution tailored to the limits of the target volume while reducing exposure of normal tissues. These techniques would then allow further tumor dose escalation. Head-and-neck tumors are some of the most attractive localizations to test conformal radiotherapy. They combine ballistic difficulties due to particularly complex shapes (nasopharynx, ethmoid) and problems due to the number and low tolerance of neighbouring organs like parotids, eyes, brainstem and spinal cord. The therapeutic irradiation of head-and-neck tumors thus remains a challenge for the radiation oncologist. Conformal radiotherapy does have a significant potential for improving local control and reducing toxicity when compared to standard radiotherapy. However, in the absence of prospective randomized trials, it is somewhat difficult at present to evaluate the real benefits drawn from 3DCRT and IMRT. The published clinical reports on the use of conformal radiotherapy are essentially dealing with dosimetric comparisons on relatively small numbers of patients. Recently, a few publications have emphasized the clinical experience several precursor teams with a suitable follow-up. This paper describes the current state-of-the-art of 3DCRT and IMRT in order to evaluate the impact of these techniques on head-and-neck cancers irradiation. (authors)

  7. Conformal atomic layer deposition of alumina on millimeter tall, vertically-aligned carbon nanotube arrays.

    Science.gov (United States)

    Stano, Kelly L; Carroll, Murphy; Padbury, Richard; McCord, Marian; Jur, Jesse S; Bradford, Philip D

    2014-11-12

    Atomic layer deposition (ALD) can be used to coat high aspect ratio and high surface area substrates with conformal and precisely controlled thin films. Vertically aligned arrays of multiwalled carbon nanotubes (MWCNTs) with lengths up to 1.5 mm were conformally coated with alumina from base to tip. The nucleation and growth behaviors of Al2O3 ALD precursors on the MWCNTs were studied as a function of CNT surface chemistry. CNT surfaces were modified through a series of post-treatments including pyrolytic carbon deposition, high temperature thermal annealing, and oxygen plasma functionalization. Conformal coatings were achieved where post-treatments resulted in increased defect density as well as the extent of functionalization, as characterized by X-ray photoelectron spectroscopy and Raman spectroscopy. Using thermogravimetric analysis, it was determined that MWCNTs treated with pyrolytic carbon and plasma functionalization prior to ALD coating were more stable to thermal oxidation than pristine ALD coated samples. Functionalized and ALD coated arrays had a compressive modulus more than two times higher than a pristine array coated for the same number of cycles. Cross-sectional energy dispersive X-ray spectroscopy confirmed that Al2O3 could be uniformly deposited through the entire thickness of the vertically aligned MWCNT array by manipulating sample orientation and mounting techniques. Following the ALD coating, the MWCNT arrays demonstrated hydrophilic wetting behavior and also exhibited foam-like recovery following compressive strain.

  8. The Role of Conformity in Relation to Cohesiveness and Intimacy in Day-Hospital Groups of Patients with Schizophrenia.

    Science.gov (United States)

    Park, Il Ho; Park, Sun Young; Choi, Sulkee; Lee, Soo Young; Kim, Jae-Jin

    2017-07-01

    Conformity is defined as the act of adjusting one's behavior to match the social responses of others. Patients with schizophrenia often adjust their maladaptive behaviors by conforming in group treatment settings. This study aimed to examine whether the opinions of group members influence conformity of patients with schizophrenia who attend day-hospital programs. Nineteen patients with schizophrenia from four different day-hospital programs and 23 healthy controls from four different social clubs completed the homographic meaning choice task under conditions of prior exposure to the pseudo-opinions of their group members, strangers, and unknown information sources. Group influences on conformity were observed when the level of group cohesiveness was high and the level of intimacy was low across participant groups. Controls did not exhibit a significant effect of group influence on conformity, whereas patients were significantly influenced by their group members when making conformity-based decisions despite significantly lower intimacy and cohesiveness levels. These findings suggest that unlike controls, patients with schizophrenia tend to respond with conformity when influenced by the opinions of their affiliated group. In patients with schizophrenia group conformity may be used to select a more accurate decision and to enhance feelings of affiliation among them.

  9. Structural alphabets derived from attractors in conformational space

    Directory of Open Access Journals (Sweden)

    Kleinjung Jens

    2010-02-01

    Full Text Available Abstract Background The hierarchical and partially redundant nature of protein structures justifies the definition of frequently occurring conformations of short fragments as 'states'. Collections of selected representatives for these states define Structural Alphabets, describing the most typical local conformations within protein structures. These alphabets form a bridge between the string-oriented methods of sequence analysis and the coordinate-oriented methods of protein structure analysis. Results A Structural Alphabet has been derived by clustering all four-residue fragments of a high-resolution subset of the protein data bank and extracting the high-density states as representative conformational states. Each fragment is uniquely defined by a set of three independent angles corresponding to its degrees of freedom, capturing in simple and intuitive terms the properties of the conformational space. The fragments of the Structural Alphabet are equivalent to the conformational attractors and therefore yield a most informative encoding of proteins. Proteins can be reconstructed within the experimental uncertainty in structure determination and ensembles of structures can be encoded with accuracy and robustness. Conclusions The density-based Structural Alphabet provides a novel tool to describe local conformations and it is specifically suitable for application in studies of protein dynamics.

  10. Quantum Conformal Algebras and Closed Conformal Field Theory

    CERN Document Server

    Anselmi, D

    1999-01-01

    We investigate the quantum conformal algebras of N=2 and N=1 supersymmetric gauge theories. Phenomena occurring at strong coupling are analysed using the Nachtmann theorem and very general, model-independent, arguments. The results lead us to introduce a novel class of conformal field theories, identified by a closed quantum conformal algebra. We conjecture that they are the exact solution to the strongly coupled large-N_c limit of the open conformal field theories. We study the basic properties of closed conformal field theory and work out the operator product expansion of the conserved current multiplet T. The OPE structure is uniquely determined by two central charges, c and a. The multiplet T does not contain just the stress-tensor, but also R-currents and finite mass operators. For this reason, the ratio c/a is different from 1. On the other hand, an open algebra contains an infinite tower of non-conserved currents, organized in pairs and singlets with respect to renormalization mixing. T mixes with a se...

  11. C-metric solution for conformal gravity with a conformally coupled scalar field

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Kun, E-mail: mengkun@tjpu.edu.cn [School of Science, Tianjin Polytechnic University, Tianjin 300387 (China); Zhao, Liu, E-mail: lzhao@nankai.edu.cn [School of Physics, Nankai University, Tianjin 300071 (China)

    2017-02-15

    The C-metric solution of conformal gravity with a conformally coupled scalar field is presented. The solution belongs to the class of Petrov type D spacetimes and is conformal to the standard AdS C-metric appeared in vacuum Einstein gravity. For all parameter ranges, we identify some of the physically interesting static regions and the corresponding coordinate ranges. The solution may contain a black hole event horizon, an acceleration horizon, either of which may be cut by the conformal infinity or be hidden behind the conformal infinity. Since the model is conformally invariant, we also discussed the possible effects of the conformal gauge choices on the structure of the spacetime.

  12. Non-conformable, partial and conformable transposition

    DEFF Research Database (Denmark)

    König, Thomas; Mäder, Lars Kai

    2013-01-01

    and the Commission regarding a directive’s outcome, play a much more strategic role than has to date acknowledged in the transposition literature. Whereas disagreement of a member state delays conformable transposition, it speeds up non-conformable transposition. Disagreement of the Commission only prolongs...... the transposition process. We therefore conclude that a stronger focus on an effective sanctioning mechanism is warranted for safeguarding compliance with directives....

  13. Conformal Einstein spaces

    International Nuclear Information System (INIS)

    Kozameh, C.N.; Newman, E.T.; Tod, K.P.

    1985-01-01

    Conformal transformations in four-dimensional. In particular, a new set of two necessary and sufficient conditions for a space to be conformal to an Einstein space is presented. The first condition defines the class of spaces conformal to C spaces, whereas the last one (the vanishing of the Bach tensor) gives the particular subclass of C spaces which are conformally related to Einstein spaces. (author)

  14. Conformal Gravity

    International Nuclear Information System (INIS)

    Hooft, G.

    2012-01-01

    The dynamical degree of freedom for the gravitational force is the metric tensor, having 10 locally independent degrees of freedom (of which 4 can be used to fix the coordinate choice). In conformal gravity, we split this field into an overall scalar factor and a nine-component remainder. All unrenormalizable infinities are in this remainder, while the scalar component can be handled like any other scalar field such as the Higgs field. In this formalism, conformal symmetry is spontaneously broken. An imperative demand on any healthy quantum gravity theory is that black holes should be described as quantum systems with micro-states as dictated by the Hawking-Bekenstein theory. This requires conformal symmetry that may be broken spontaneously but not explicitly, and this means that all conformal anomalies must cancel out. Cancellation of conformal anomalies yields constraints on the matter sector as described by some universal field theory. Thus black hole physics may eventually be of help in the construction of unified field theories. (author)

  15. The place of conformal radiotherapy in the routine work: national investigation of SFRO members'opinion

    International Nuclear Information System (INIS)

    Lagrange, J.L.; Lipinski, F.

    2001-01-01

    National French investigation of the using of conformal radiotherapy in routine work, has been made in 2001, in 180 radiotherapeutic centers. Eighty responses have been obtained and analyzed. Conformal radiotherapy is used in 88% and virtual simulation in 60% of these centers. There is a heterogeneity in the equipment of these institutions, most of them have one or two machines. The accelerator equipment differs, and the availability of multi-leaf collimators and electronic portal imaging is limited. Actually only eleven centers have IMRT, eight have projects to install. Only six centers have CT-scans, used mainly for simulation. In 75% of centers conformal radiotherapy have been used in the treatment of CNS-tumors, head and neck cancers, prostate, and non-small cell lung carcinoma. If there are more equipment and human facilities to use conformal radiotherapy, this treatment can be proposed to patients with breast cancer, rectal and gynecological tumors. According 90% of responses, all prostatic cancers need conformal radiotherapy. The analysis of routine use of conformal radiotherapy in France shows an important heterogeneity but it seems that there is an agreement with objectives of this treatment. (authors)

  16. Conformational analysis of 9β,19-cyclopropyl sterols: Detection of the pseudoplanar conformer by nuclear Overhauser effects and its functional implications

    International Nuclear Information System (INIS)

    Nes, W.D.; Benson, M.; Lundin, R.E.; Le, P.H.

    1988-01-01

    Nuclear Overhauser difference spectroscopy and variable temperature studies of the 9β,19-cyclopropyl sterols 24,25-dehydropollinastanol (4,4-desmethyl-5α-cycloart-24-en-3β-ol) and cyclolaudenol [(24S)-24-methyl-5α-cycloart-25(27)-en-3β-ol] have shown the solution conformation of the B/C rings to be twist-chair/twist-boat rather than boat/chair as suggested in the literature. This is very similar to the known crystal structure conformation of 9β,19-cyclopropyl sterols. The effect of these conformations on the molecular shape is highly significant; the first conformation orients into a pseudoplanar or flat shape analogous to lanosterol, whereas the latter conformation exhibits a bent shape. The results are interpreted to imply that, for conformational reasons, cyclopropyl sterols can be expected to maintain the pseudoplanar shape in membrane bilayers

  17. Investigating ion channel conformational changes using voltage clamp fluorometry.

    Science.gov (United States)

    Talwar, Sahil; Lynch, Joseph W

    2015-11-01

    Ion channels are membrane proteins whose functions are governed by conformational changes. The widespread distribution of ion channels, coupled with their involvement in most physiological and pathological processes and their importance as therapeutic targets, renders the elucidation of these conformational mechanisms highly compelling from a drug discovery perspective. Thanks to recent advances in structural biology techniques, we now have high-resolution static molecular structures for members of the major ion channel families. However, major questions remain to be resolved about the conformational states that ion channels adopt during activation, drug modulation and desensitization. Patch-clamp electrophysiology has long been used to define ion channel conformational states based on functional criteria. It achieves this by monitoring conformational changes at the channel gate and cannot detect conformational changes occurring in regions distant from the gate. Voltage clamp fluorometry involves labelling cysteines introduced into domains of interest with environmentally sensitive fluorophores and inferring structural rearrangements from voltage or ligand-induced fluorescence changes. Ion channel currents are monitored simultaneously to verify the conformational status. By defining real time conformational changes in domains distant from the gate, this technique provides unexpected new insights into ion channel structure and function. This review aims to summarise the methodology and highlight recent innovative applications of this powerful technique. This article is part of the Special Issue entitled 'Fluorescent Tools in Neuropharmacology'. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Quality assurance for 3D conformal radiation therapy

    International Nuclear Information System (INIS)

    Purdy, J.A.; Harms, W.B.

    1998-01-01

    Three-dimensional conformal radiation therapy (3D CRT) can be considered as an integrated process of treatment planning, delivery, and verification that attempts to conform the prescription dose closely to the target volume while limiting dose to critical normal structures. Requiring the prescription dose to conform as closely as possible to the target volume raises the level of the precision and accuracy requirements generally found in conventional radiation therapy. 3D CRT treatment planning requires robust patient immobilization/repositioning systems and volumetric image data (CT and/or MR) acquired in the treatment position. 3D treatment planning more explicitly details the particular of a patient's treatment than was ever possible with 2D treatment planning. In 1992, we implemented a formal 3D treatment planning service in our clinic and at the same time instituted a formal quality assurance (QA) program addressing the individual procedures that make up the 3D CRT process. Our 3D QA program includes systematic testing of the hardware and software used in the 3D treatment planning process, careful review of each patient's treatment plan, careful review of the physical implementation of the treatment plan, a peer review 3D QA Case Conference, and a formal continuing education program in 3D CRT for our radiation therapy staff. This broad 3D QA program requires the involvement of physicians, physicists, dosimetrists, and the treating radiation therapists that complete the team responsible for 3D CRT.3D CRT capabilities change the kinds of radiation therapy treatments that are possible and that changes the process with which treatment planning and treatment delivery are performed. There is no question that 3D CRT shows significant potential for improving the quality of radiation therapy and improving the efficiency with which it can be delivered. However, its implementation and wide spread use is still in its initial stages. The techniques used for 3D treatment

  19. Understanding modern magnets through conformal mapping

    International Nuclear Information System (INIS)

    Halbach, K.

    1989-10-01

    I want to show with the help of a number of examples that conformal mapping is a unique and enormously powerful tool for thinking about, and solving, problems. Usually one has to write down only a few equations, and sometimes none at all exclamation point When I started getting involved in work for which conformal mapping seemed to be a powerful tool, I did not think that I would ever be able to use that technique successfully because it seemed to require a nearly encyclopedic memory, an impression that was strengthened when I saw K. Kober's Dictionary of Conformal Representations. This attitude changed when I started to realize that beyond the basics of the theory of a function of a complex variable, I needed to know only about a handful of conformal maps and procedures. Consequently, my second goal for this talk is to show that in most cases conformal mapping functions can be obtained by formulating the underlying physics appropriately. This means particularly that encyclopedic knowledge of conformal maps is not necessary for successful use of conformal mapping techniques. To demonstrate these facts I have chosen examples from an area of physics/engineering in which I am active, namely accelerator physics. In order to do that successfully I start with a brief introduction into high energy charged particle storage ring technology, even though not all examples used in this paper to elucidate my points come directly from this particular field of accelerator technology

  20. Conformal avoidance helical tomotherapy for dogs with nasopharyngeal tumors

    International Nuclear Information System (INIS)

    Welsh, J.S.; Turek, M.; Mackie, T.R.; Miller, P.; Mehta, M.P.; Forrest, L.J.

    2003-01-01

    Helical tomotherapy provides a unique means of delivering intensity-modulated radiation therapy (IMRT) using a novel treatment unit, which merges features of a linear accelerator with a helical CT scanner. Thanks to the CT imaging capacity, targeted regions can be visualized prior to, during, or immediately after each treatment. Such image-guidance through megavoltage CT will allow the realization and refinement of the concept of adaptive radiotherapy - the reconstruction of the actually delivered daily dose (as opposed to planned dose) accompanied by prescription adjustments when appropriate. In addition to this unique feature, helical tomotherapy promises further improvements in the specific avoidance of critical normal structures, i.e. conformal avoidance, the counterpart of conformal therapy. The first definitive treatment protocol using helical tomotherapy is presently underway for dogs with nasopharyngeal tumors. In general, such tumors can be treated with conventional external beam radiation therapy but at the cost of severe ocular toxicity due to the anatomy of the canine head. These are readily measurable toxicities and are almost universal in incidence; therefore, the canine nasopharyngeal tumor presents an ideal model to assess the ability to conformally avoid critical structures. It is hoped that conformal avoidance helical tomotherapy will improve tumor control via dose-escalation while reducing ocular toxicity in these veterinary patients. A total of 10 fractions are scheduled for these patients; the first 3 dogs have all received at least 7 fractions delivered via helical tomotherapy. Although preliminary, the first 3 dogs treated have not shown any evidence of ocular toxicity in this ongoing study

  1. The role of Cobalt-60 source in Intensity Modulated Radiation Therapy: From modeling finite sources to treatment planning and conformal dose delivery

    Science.gov (United States)

    Dhanesar, Sandeep Kaur

    Cobalt-60 (Co-60) units played an integral role in radiation therapy from the mid-1950s to the 1970s. Although they continue to be used to treat cancer in some parts of the world, their role has been significantly reduced due to the invention of medical linear accelerators. A number of groups have indicated a strong potential for Co-60 units in modern radiation therapy. The Medical Physics group at the Cancer Center of the Southeastern Ontario and Queen's University has shown the feasibility of Intensity Modulated Radiation Therapy (IMRT) via simple conformal treatment planning and dose delivery using a Co-60 unit. In this thesis, initial Co-60 tomotherapy planning investigations on simple uniform phantoms are extended to actual clinical cases based on patient CT data. The planning is based on radiation dose data from a clinical Co-60 unit fitted with a multileaf collimator (MLC) and modeled in the EGSnrc Monte Carlo system. An in house treatment planning program is used to calculate IMRT dose distributions. Conformal delivery in a single slice on a uniform phantom based on sequentially delivered pencil beams is verified by Gafchromic film. Volumetric dose distributions for Co-60 serial tomotherapy are then generated for typical clinical sites that had been treated at our clinic by conventional 6MV IMRT using Varian Eclipse treatment plans. The Co-60 treatment plans are compared with the clinical IMRT plans using conventional matrices such as dose volume histograms (DVH). Dose delivery based on simultaneously opened MLC leaves is also explored and a novel MLC segmentation method is proposed. In order to increase efficiency of dose calculations, a novel convolution based fluence model for treatment planning is also proposed. The ion chamber measurements showed that the Monte Carlo modeling of the beam data under the MIMiC MLC is accurate. The film measurements from the uniform phantom irradiations confirm that IMRT plans from our in-house treatment planning system

  2. Conformal symmetry in two-dimensional space: recursion representation of conformal block

    International Nuclear Information System (INIS)

    Zamolodchikov, A.B.

    1988-01-01

    The four-point conformal block plays an important part in the analysis of the conformally invariant operator algebra in two-dimensional space. The behavior of the conformal block is calculated in the present paper in the limit in which the dimension Δ of the intermediate operator tends to infinity. This makes it possible to construct a recursion relation for this function that connects the conformal block at arbitrary Δ to the blocks corresponding to the dimensions of the zero vectors in the degenerate representations of the Virasoro algebra. The relation is convenient for calculating the expansion of the conformal block in powers of the uniformizing parameters q = i π tau

  3. Conformity of LINAC-Based Stereotactic Radiosurgery Using Dynamic Conformal Arcs and Micro-Multileaf Collimator

    International Nuclear Information System (INIS)

    Hazard, Lisa J.; Wang, Brian; Skidmore, Thomas B.; Chern, Shyh-Shi; Salter, Bill J.; Jensen, Randy L.; Shrieve, Dennis C.

    2009-01-01

    Purpose: To assess the conformity of dynamic conformal arc linear accelerator-based stereotactic radiosurgery and to describe a standardized method of isodose surface (IDS) selection. Methods and Materials: In 174 targets, the conformity index (CI) at the prescription IDS used for treatment was calculated as CI = (PIV/PVTV)/(PVTV/TV), where TV is the target volume, PIV (prescription isodose volume) is the total volume encompassed by the prescription IDS, and PVTV is the TV encompassed by the IDS. In addition, a 'standardized' prescription IDS (sIDS) was chosen according to the following criteria: 95% of the TV was encompassed by the PIV and 99% of TV was covered by 95% of the prescription dose. The CIs at the sIDS were also calculated. Results: The median CI at the prescription IDS and sIDS was 1.63 and 1.47, respectively (p < 0.001). In 132 of 174 cases, the volume of normal tissue in the PIV was reduced by the prescription to the sIDS compared with the prescription IDS, in 20 cases it remained unchanged, and in 22 cases it was increased. Conclusion: The CIs obtained with linear accelerator-based stereotactic radiosurgery are comparable to those previously reported for gamma knife stereotactic radiosurgery. Using a uniform method to select the sIDS, adequate target coverage was usually achievable with prescription to an IDS greater than that chosen by the treating physician (prescription IDS), providing sparing of normal tissue. Thus, the sIDS might aid physicians in identifying a prescription IDS that balances coverage and conformity

  4. Conformers, infrared spectrum, UV-induced photochemistry, and near-IR-induced generation of two rare conformers of matrix-isolated phenylglycine

    Science.gov (United States)

    Borba, Ana; Gómez-Zavaglia, Andrea; Fausto, Rui

    2014-10-01

    The conformational space of α-phenylglycine (PG) have been investigated theoretically at both the DFT/B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) levels of approximation. Seventeen different minima were found on the investigated potential energy surfaces, which are characterized by different dominant intramolecular interactions: type I conformers are stabilized by hydrogen bonds of the type N-H...O=C, type II by a strong O-H...N hydrogen bond, type III by weak N-H...O-H hydrogen bonds, and type IV by a C=O...H-C contact. The calculations indicate also that entropic effects are relevant in determining the equilibrium populations of the conformers of PG in the gas phase, in particular in the case of conformers of type II, where the strong intramolecular O-H...N hydrogen bond considerably diminishes entropy by reducing the conformational mobility of the molecule. In consonance with the relative energies of the conformers and barriers for conformational interconversion, only 3 conformers of PG were observed for the compound isolated in cryogenic Ar, Xe, and N2 matrices: the conformational ground state (ICa), and forms ICc and IITa. All other significantly populated conformers existing in the gas phase prior to deposition convert either to conformer ICa or to conformer ICc during matrix deposition. The experimental observation of ICc had never been achieved hitherto. Narrowband near-IR irradiation of the first overtone of νOH vibrational mode of ICa and ICc in nitrogen matrices (at 6910 and 6930 cm-1, respectively) led to selective generation of two additional conformers of high-energy, ITc and ITa, respectively, which were also observed experimentally for the first time. In addition, these experiments also provided the key information for the detailed vibrational characterization of the 3 conformers initially present in the matrices. On the other hand, UV irradiation (λ = 255 nm) of PG isolated in a xenon matrix revealed that PG undergoes facile photofragmentation

  5. Conformers, infrared spectrum, UV-induced photochemistry, and near-IR-induced generation of two rare conformers of matrix-isolated phenylglycine

    International Nuclear Information System (INIS)

    Borba, Ana; Fausto, Rui; Gómez-Zavaglia, Andrea

    2014-01-01

    The conformational space of α-phenylglycine (PG) have been investigated theoretically at both the DFT/B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) levels of approximation. Seventeen different minima were found on the investigated potential energy surfaces, which are characterized by different dominant intramolecular interactions: type I conformers are stabilized by hydrogen bonds of the type N–H···O=C, type II by a strong O–H···N hydrogen bond, type III by weak N–H···O–H hydrogen bonds, and type IV by a C=O···H–C contact. The calculations indicate also that entropic effects are relevant in determining the equilibrium populations of the conformers of PG in the gas phase, in particular in the case of conformers of type II, where the strong intramolecular O–H···N hydrogen bond considerably diminishes entropy by reducing the conformational mobility of the molecule. In consonance with the relative energies of the conformers and barriers for conformational interconversion, only 3 conformers of PG were observed for the compound isolated in cryogenic Ar, Xe, and N 2 matrices: the conformational ground state (ICa), and forms ICc and IITa. All other significantly populated conformers existing in the gas phase prior to deposition convert either to conformer ICa or to conformer ICc during matrix deposition. The experimental observation of ICc had never been achieved hitherto. Narrowband near-IR irradiation of the first overtone of νOH vibrational mode of ICa and ICc in nitrogen matrices (at 6910 and 6930 cm −1 , respectively) led to selective generation of two additional conformers of high-energy, ITc and ITa, respectively, which were also observed experimentally for the first time. In addition, these experiments also provided the key information for the detailed vibrational characterization of the 3 conformers initially present in the matrices. On the other hand, UV irradiation (λ = 255 nm) of PG isolated in a xenon matrix revealed that PG

  6. Conformational analysis of oligosaccharides and polysaccharides using molecular dynamics simulations.

    Science.gov (United States)

    Frank, Martin

    2015-01-01

    Complex carbohydrates usually have a large number of rotatable bonds and consequently a large number of theoretically possible conformations can be generated (combinatorial explosion). The application of systematic search methods for conformational analysis of carbohydrates is therefore limited to disaccharides and trisaccharides in a routine analysis. An alternative approach is to use Monte-Carlo methods or (high-temperature) molecular dynamics (MD) simulations to explore the conformational space of complex carbohydrates. This chapter describes how to use MD simulation data to perform a conformational analysis (conformational maps, hydrogen bonds) of oligosaccharides and how to build realistic 3D structures of large polysaccharides using Conformational Analysis Tools (CAT).

  7. Treatment planning evaluation of non-coplanar techniques for conformal radiotherapy of the prostate

    International Nuclear Information System (INIS)

    Bedford, James L.; Henrys, Anthony J.; Dearnaley, David P.; Khoo, Vincent S.

    2005-01-01

    Background and purpose: To evaluate the benefit of using non-coplanar treatment plans for irradiation of two different clinical treatment volumes: prostate only (PO) and the prostate plus seminal vesicles (PSV). Material and methods: An inverse planning algorithm was used to produce three-field, four-field, five-field and six-field non-coplanar treatment plans without intensity-modulation in ten patients. These were compared against a three-field coplanar plan. A dose of 74 Gy was prescribed to the isocentre. Plans were compared using the minimum dose to the planning target volume (PTV), maximum dose to the small bowel, and irradiated volumes of rectum, bladder and femoral head. Biological indices were also evaluated. Results: For the PO group, volume of rectum irradiated to 60 Gy (V 60 ) was 22.5±3.7% for the coplanar plan, and 21.5±5.3% for the five-field non-coplanar plan, which was the most beneficial (p=0.3). For the PSV group, the five-field non-coplanar plan was again the most beneficial. Rectal V 60 was in this case reduced from 41.5±10.4% for the coplanar plan to 35.2±9.3% for the non-coplanar plan (p=0.02). Conclusions: The use of non-coplanar beams in conformal prostate radiotherapy provides a small increase in rectal sparing, more significantly with PSV volumes than for PO volumes

  8. Conformal fields in prostate radiotherapy: A comparison between measurement, calculation and simulation

    Directory of Open Access Journals (Sweden)

    Seied R Mahdavi

    2012-01-01

    Full Text Available Aims: The objective of this study is to evaluate the accuracy of a treatment planning system (TPS for calculating the dose distribution parameters in conformal fields (CF. Dosimetric parameters of CF′s were compared between measurement, Monte Carlo simulation (MCNP4C and TPS calculation. Materials and Methods: Field analyzer water phantom was used for obtaining percentage depth dose (PDD curves and beam profiles (BP of different conformal fields. MCNP4C was used to model conformal fields dose specification factors and head of linear accelerator varian model 2100C/D. Results: Results showed that the distance to agreement (DTA and dose difference (DD of our findings were well within the acceptance criteria of 3 mm and 3%, respectively. Conclusions: According to this study it can be revealed that TPS using equivalent tissue air ratio calculation method is still convenient for dose prediction in non small conformal fields normally used in prostate radiotherapy. It was also showed that, since there is a close correlation with Monte Carlo simulation, measurements and TPS, Monte Carlo can be further confirmed for implementation and calculation dose distribution in non standard and complex conformal irradiation field for treatment planning systems.

  9. Three dimensional conformal radiotherapy for the treatment of prostate cancer: low risk of chronic rectal morbidity observed in a large series of patients

    International Nuclear Information System (INIS)

    Sandler, Howard M.; McLaughlin, P. William; Ten Haken, Randall K.; Addison, Heather; Forman, Jeffrey; Lichter, Allen

    1995-01-01

    Purpose: Three dimensional conformal radiotherapy (3D CRT) may provide a technique to increase the dose delivered to target tissues while sparing uninvolved normal structures. To evaluate the role of 3D treatment in reducing the treatment toxicity, we analyzed the chronic rectal morbidity observed in a large group of patients undergoing radiotherapy for prostate cancer. Methods and Materials: From 1987 through 1992, 721 prostate cancer patients were treated with 3D CRT at the University of Michigan or Providence Hospital. All had axial computed tomography (CT) specifically for RT planning, multiple structures contoured on the axial images, and beam's-eye-view conformal beams edited to provide 3D dose coverage. Using current American Joint Commission (AJCC) staging, 537 patients had T1-T2 tumors, 123 had T3-T4 tumors, and 60 were treated postprostatectomy. Pelvic lymph nodes were treated in 462 patients. Prostate boosts were delivered with four-field axial, six-field axial, or four-field oblique, nonaxial fields. The median dose was 68.40 Gy (range 59.4-80.4). Median follow-up was 20.4 months; 175 were followed more than 3 years. All complications have been graded conservatively using the RTOG system. Results: Using a Cox proportional hazard's model, patient age, T-stage, prescribed dose, pelvic treatment, and boost technique were analyzed. The factor most strongly related to risk of morbidity was dose (p = 0.05); however, the boost technique was also related: the four-field oblique field had the lowest relative risk. Most episodes of rectal morbidity have been mild: 82 Grade 1 or 2. There have been only 14 more serious complications including 12 Grade 3 and 2 Grade 4. The actuarial risk of a Grade 3 or 4 complication is 3% at 3 and 5 years. Conclusions: A very small proportion of patients treated with 3D CRT had significant rectal morbidity related to RT, supporting the use of conformal treatment planning and dose delivery as a mechanism to minimize complications

  10. Cost-benefit analysis of 3D conformal radiation therapy. Treatment of prostate cancer as a model

    International Nuclear Information System (INIS)

    Cho, K.H.; Khan, F.M.; Levitt, S.H.

    1999-01-01

    Three-dimensional conformal radiation therapy (3D-CRT) is a promising new treatment technique based on the principle that improved precision in both tumor definition and dose delivery will enhance outcomes by maximizing dose to the tumor area while minimizing dose to normal tissue. Using a cost-benefit analysis, in terms of outcomes, we first examined the overall risks and benefits of 3D-CRT. We then used the treatment of prostate cancer as a model to compare actual clinical outcomes reported between 3D-CRT and standard radiation therapy (SRT). Our analysis shows that application of 3D-CRT to the clinical setting remains difficult because of the continual difficulties of target definition, and that dose escalation cannot yet be justified on the basis of the lack of benefit found, and suggested increased late toxicity, in most of the dose escalation series compared with SRT. (orig.)

  11. Conformal radiotherapy for locally advanced juvenile nasopharyngeal angio-fibroma

    Directory of Open Access Journals (Sweden)

    Supriya Mallick

    2015-01-01

    Full Text Available Purpose: To assess the efficacy of radiation in the treatment of juvenile nasopharyngeal angiofibroma (JNA. Materials and Methods: Data were retrieved for JNA treated with radiotherapy from 1987-2012. The demographics, treatment and outcome data were recorded in predesigned proforma. Results: Data of 32 patients were retrieved. Median age was 17 years (range: 12-33 years. All patients received radiation because of refractory, residual or unresectable locally advanced disease. All patients were planned with a three-dimensional conformal technique (3DCRT. The median radiation dose was 30 Gray (range: 30-45 Gray. Median follow-up was 129 months (range: 1-276 months. At the last follow-up, 13 patients were found to have a radiological complete response. Two patients progressed 38 and 43 months after completion of treatment and opted for alternative treatment. One patient developed squamous cell carcinoma of the nasal ale 15 years after radiation. Conclusion: Conformal radiotherapy shows promise as an alternative treatment approach for locally advanced JNA and confers long-term disease control with minimal toxicity.

  12. Computer-controlled 3-D treatment delivery

    International Nuclear Information System (INIS)

    Fraass, Benedick A.

    1995-01-01

    Purpose/Objective: This course will describe the use of computer-controlled treatment delivery techniques for treatment of patients with sophisticated conformal therapy. In particular, research and implementation issues related to clinical use of computer-controlled conformal radiation therapy (CCRT) techniques will be discussed. The possible/potential advantages of CCRT techniques will be highlighted using results from clinical 3-D planning studies. Materials and Methods: In recent years, 3-D treatment planning has been used to develop and implement 3-D conformal therapy treatment techniques, and studies based on these conformal treatments have begun to show the promise of conformal therapy. This work has been followed by the development of commercially-available multileaf collimator and computer control systems for treatment machines. Using these (and other) CCRT devices, various centers are beginning to clinically use complex computer-controlled treatments. Both research and clinical CCRT treatment techniques will be discussed in this presentation. General concepts and requirements for CCRT will be mentioned. Developmental and clinical experience with CCRT techniques from a number of centers will be utilized. Results: Treatment planning, treatment preparation and treatment delivery must be approached in an integrated fashion in order to clinically implement CCRT treatment techniques, and the entire process will be discussed. Various CCRT treatment methodologies will be reviewed from operational, dosimetric, and technical points of view. The discussion will concentrate on CCRT techniques which are likely to see rather wide dissemination over the next several years, including particularly the use of multileaf collimators (MLC), dynamic and segmental conformal therapy, conformal field shaping, and other related techniques. More advanced CCRT techniques, such as the use of individualized intensity modulation of beams or segments, and the use of computer

  13. Conformal Infinity

    Directory of Open Access Journals (Sweden)

    Frauendiener Jörg

    2000-08-01

    Full Text Available The notion of conformal infinity has a long history within the research in Einstein's theory of gravity. Today, ``conformal infinity'' is related with almost all other branches of research in general relativity, from quantisation procedures to abstract mathematical issues to numerical applications. This review article attempts to show how this concept gradually and inevitably evolved out of physical issues, namely the need to understand gravitational radiation and isolated systems within the theory of gravitation and how it lends itself very naturally to solve radiation problems in numerical relativity. The fundamental concept of null-infinity is introduced. Friedrich's regular conformal field equations are presented and various initial value problems for them are discussed. Finally, it is shown that the conformal field equations provide a very powerful method within numerical relativity to study global problems such as gravitational wave propagation and detection.

  14. Conformal Infinity.

    Science.gov (United States)

    Frauendiener, Jörg

    2004-01-01

    The notion of conformal infinity has a long history within the research in Einstein's theory of gravity. Today, "conformal infinity" is related to almost all other branches of research in general relativity, from quantisation procedures to abstract mathematical issues to numerical applications. This review article attempts to show how this concept gradually and inevitably evolved from physical issues, namely the need to understand gravitational radiation and isolated systems within the theory of gravitation, and how it lends itself very naturally to the solution of radiation problems in numerical relativity. The fundamental concept of null-infinity is introduced. Friedrich's regular conformal field equations are presented and various initial value problems for them are discussed. Finally, it is shown that the conformal field equations provide a very powerful method within numerical relativity to study global problems such as gravitational wave propagation and detection.

  15. CONSERVATIVE TREATMENT IN LOCALLY AND LOCALLY-ADVANCED PROSTATE CANCER USING CONFORMAL RADIOTHERAPY

    Directory of Open Access Journals (Sweden)

    Tkachev Sergey Ivanovich

    2013-01-01

    Full Text Available The combination of androgen deprivation and radiotherapy increase the probability of diseases full regresses and survival rate. Modern technical and technological opportunities of 3D CRT allow to increase total dose to prostate up to 72-76Gy vs. radiotherapy of 66-70Gy. In this study we compare the rates of post radiation toxicity and the efficiency of treatment for the patients receiving conventional radiotherapy and 3D CRT. The use of 3D CRT has not only result to increase of 10-years recurrence free survival rate from 74% (I grope to 86,5% (II grope, р=0,01, but also to increase of 10-years overall survival, 70% versus 78,4% (р=0,04. The proposed version of conformal 3D CRT radiation therapy made ​​it possible compared to conventional 2D RT radiation therapy by increasing SOD radiation to the tumor, accuracy and compliance with the quality assurance of radiation therapy significantly reduce rates of recurrence and significantly increase the performance of 10-year overall and disease-free survival.

  16. Effects of Pulsed Electric Field (PEF) Treatment on Enhancing Activity and Conformation of α-Amylase.

    Science.gov (United States)

    Tian, Mei-ling; Fang, Ting; Du, Mu-ying; Zhang, Fu-sheng

    2016-04-01

    To explore an efficient, safe, and speedy application of pulsed electric field (PEF) technology for enzymatic modification, effects of PEF treatment on the enzymatic activity, property and kinetic parameters of α-amylase were investigated. Conformational transitions were also studied with the aid of circular dichroism (CD) and fluorescence spectra. The maximum enzymatic activity of α-amylase was obtained under 15 kV/cm electric field intensity and 100 mL/min flow velocity PEF treatment, in which the enzymatic activity increased by 22.13 ± 1.14% compared with control. The activation effect could last for 18 h at 4 °C. PEF treatment could widen the range of optimum temperature for α-amylase, however, it barely exerted any effect on the optimum pH. On the other hand, α-amylase treated by PEF showed an increase of Vmax, t1/2 and ΔG, whereas a decrease of Km and k were observed. Furthermore, it can be observed from fluorescence and CD spectra that PEF treatment had increased the number of amino acid residues, especially that of tryptophan, on α-amylase surface with enhanced α-helices by 34.76% and decreased random coil by 12.04% on α-amylase when compared with that of untreated. These changes in structure had positive effect on enhancing α-amylase activity and property.

  17. Conformal Infinity

    Directory of Open Access Journals (Sweden)

    Frauendiener Jörg

    2004-01-01

    Full Text Available The notion of conformal infinity has a long history within the research in Einstein's theory of gravity. Today, 'conformal infinity' is related to almost all other branches of research in general relativity, from quantisation procedures to abstract mathematical issues to numerical applications. This review article attempts to show how this concept gradually and inevitably evolved from physical issues, namely the need to understand gravitational radiation and isolated systems within the theory of gravitation, and how it lends itself very naturally to the solution of radiation problems in numerical relativity. The fundamental concept of null-infinity is introduced. Friedrich's regular conformal field equations are presented and various initial value problems for them are discussed. Finally, it is shown that the conformal field equations provide a very powerful method within numerical relativity to study global problems such as gravitational wave propagation and detection.

  18. Conformational studies of self-organized regioregular poly(3-dodecylthiophene)s using non-contact atomic force microscopy in ultra high vacuum condition

    International Nuclear Information System (INIS)

    Tanaka, Shukichi; Grevin, Benjamin; Rannou, Patrice; Suzuki, Hitoshi; Mashiko, Shinro

    2006-01-01

    Conformations of one of the variations of π-conjugated poly-alkylthiophene, poly(3-dodecylthiophene)s (P3DDT)s on the surface in ultra high vacuum (UHV) were investigated by non-contact atomic force microscopy (NC-AFM) operated by frequency-modulation mode (FM-mode). From individual molecules to several multi-layered ones, polymer chains on the surface were clearly resolved on conducting highly oriented pyrolytic graphite (HOPG) substrates and insulating mica ones, respectively. Solvent evaporation was found to have two stages, which influenced the diffusion, ordering, and adhesion processes of polymer chains on the substrate. To keep the ordered conformations of deposited polymer chains when they are transferred from ambient condition to UHV, these evaporation processes should be carefully considered. The initial conformation of polymers on the substrate was found to depend strongly on the lattice matching conditions and interactions between polymers and substrates. Formations of stripe-like structures of P3DDT polymers were found on the mica substrates, which is promising for device application

  19. Study on a Novel Gelled Foam for Conformance Control in High Temperature and High Salinity Reservoirs

    Directory of Open Access Journals (Sweden)

    Tong Li

    2018-05-01

    Full Text Available A novel gelled foam for conformance control was investigated for its ability to enhance oil recovery (EOR in high temperature and high salinity reservoirs. The formulation optimization, foaming performance, and core flooding performance of the gelled foam were systematically evaluated under harsh reservoir conditions. The gelled foam formulation was optimized with 0.4% polymer (hydrolyzed polyacrylamide; HPAM, 0.06% cross-linker (phenolic and 0.2% foaming agent (sulphobetaine; SB. The addition of the gel improved the stability of the foam system by 3.8 times that of traditional foam. A stabilization mechanism in the gelled foam was proposed to describe the stabilization process of the foam film. The uniformly distributed three-dimensional network structure of the gel provided a thick protective layer for the foam system that maintained the stability of the foam and improved the strength and thickness of the liquid film. The gelled foam exhibited good formation adaptability, profile control, and EOR performance. The foam flowed into the high permeability layer, plugged the dominant channel, and increased the swept volume. Oil recovery was enhanced by 29.4% under harsh high -temperature and high salinity conditions.

  20. Conformable pressure vessel for high pressure gas storage

    Science.gov (United States)

    Simmons, Kevin L.; Johnson, Kenneth I.; Lavender, Curt A.; Newhouse, Norman L.; Yeggy, Brian C.

    2016-01-12

    A non-cylindrical pressure vessel storage tank is disclosed. The storage tank includes an internal structure. The internal structure is coupled to at least one wall of the storage tank. The internal structure shapes and internally supports the storage tank. The pressure vessel storage tank has a conformability of about 0.8 to about 1.0. The internal structure can be, but is not limited to, a Schwarz-P structure, an egg-crate shaped structure, or carbon fiber ligament structure.

  1. Investigation of the Dirac Equation by Using the Conformable Fractional Derivative

    Science.gov (United States)

    Mozaffari, F. S.; Hassanabadi, H.; Sobhani, H.; Chung, W. S.

    2018-05-01

    In this paper,the Dirac equation is constructed using the conformable fractional derivative so that in its limit for the fractional parameter, the normal version is recovered. Then, the Cornell potential is considered as the interaction of the system. In this case, the wave function and the energy eigenvalue equation are derived with the aim of the bi-confluent Heun functions. use of the conformable fractional derivative is proven to lead to a branching treatment for the energy of the system. Such a treatment is obvious for small values of the fractional parameter, and a united value as the fractional parameter approaches unity.

  2. Interim report of image-guided conformal high-dose-rate brachytherapy for patients with unfavorable prostate cancer: the William Beaumont Phase II dose-escalating trial

    International Nuclear Information System (INIS)

    Martinez, Alvaro A.; Kestin, Larry L.; Stromberg, Jannifer S.; Gonzalez, Jose A.; Wallace, Michelle; Gustafson, Gary S.; Edmundson, Gregory K.; Spencer, William; Vicini, Frank A.

    2000-01-01

    Purpose: We analyzed our institution's experience treating patients with unfavorable prostate cancer in a prospective Phase II dose-escalating trial of external beam radiation therapy (EBRT) integrated with conformal high-dose-rate (HDR) brachytherapy boosts. This interim report discusses treatment outcome and prognostic factors using this treatment approach. Methods and Materials: From November 1991 through February 1998, 142 patients with unfavorable prostate cancer were prospectively treated in a dose-escalating trial with pelvic EBRT in combination with outpatient HDR brachytherapy at William Beaumont Hospital. Patients with any of the following characteristics were eligible: pretreatment prostate-specific antigen (PSA) ≥ 10.0 ng/ml, Gleason score ≥ 7, or clinical stage T2b or higher. All patients received pelvic EBRT to a median total dose of 46.0 Gy. Pelvic EBRT was integrated with ultrasound-guided transperineal conformal interstitial iridium-192 HDR implants. From 1991 to 1995, 58 patients underwent three conformal interstitial HDR implants during the first, second, and third weeks of pelvic EBRT. After October 1995, 84 patients received two interstitial implants during the first and third weeks of pelvic EBRT. The dose delivered via interstitial brachytherapy was escalated from 5.50 Gy to 6.50 Gy for each implant in those patients receiving three implants, and subsequently, from 8.25 Gy to 9.50 Gy per fraction in those patients receiving two implants. To improve implant quality and reduce operator dependency, an on-line, image-guided interactive dose optimization program was utilized during each HDR implant. No patient received hormonal therapy unless treatment failure was documented. The median follow-up was 2.1 years (range: 0.2-7.2 years). Biochemical failure was defined according to the American Society for Therapeutic Radiology and Oncology Consensus Panel definition. Results: The pretreatment PSA level was ≥ 10.0 ng/ml in 51% of patients. The

  3. Evaluation of the dose distribution of dynamic conical conformal therapy using a C-arm mounted accelerator

    International Nuclear Information System (INIS)

    Nakagawa, Keiichi; Aoki, Yukimasa; Ohtomo, Kuni

    2001-01-01

    Conformal radiation therapy, which is widely utilized in Japan as a standard, highly precise technique has limited advantage in dose confinement because of its coplanar beam entry. An improved form of conformal therapy is delivered by a linac mounted on a C-arm rotatable gantry. The linac head was designed to move along the C-arm with a maximum angle of 60 degrees. Simultaneous rotation of the gantry creates a Dynamic Conical irradiation technique. Dynamic Conical Conformal Therapy (Dyconic Therapy) was developed by combining the technique with continuous MLC motion based on beam's eye views of the target volume. Dose distributions were measured in a phantom using film densitometry and compared with conventional conformal radiation therapy. The measurements showed that the dose distribution conformed to the target shape identified by CT. In addition, the dose distribution for a cancer patient was evaluated through the use of DVHs generated by a treatment planning system. These measurements showed that the dose distribution along the patient's long axis conformed to the shape of the target volume. DVH analysis, however, did not indicate superiority of the present technique over the conventional technique. Angulation of the C-arm gantry allowed the primary beam to strike a larger area of the therapy room. This necessitated adding shielding to the walls and ceiling of the treatment room. It was confirmed that the leakage radiation was reduced to a negligible level by adding an iron plate 20 cm thick to several places on the side walls, by adding an iron plate 9 cm thick to several places on the ceiling, and by increasing the thickness of the concrete ceiling from 70 to 140 cm. The possible usefulness of Dyconic Therapy was confirmed. (author)

  4. Irreversibility and higher-spin conformal field theory

    Science.gov (United States)

    Anselmi, Damiano

    2000-08-01

    I discuss the properties of the central charges c and a for higher-derivative and higher-spin theories (spin 2 included). Ordinary gravity does not admit a straightforward identification of c and a in the trace anomaly, because it is not conformal. On the other hand, higher-derivative theories can be conformal, but have negative c and a. A third possibility is to consider higher-spin conformal field theories. They are not unitary, but have a variety of interesting properties. Bosonic conformal tensors have a positive-definite action, equal to the square of a field strength, and a higher-derivative gauge invariance. There exists a conserved spin-2 current (not the canonical stress tensor) defining positive central charges c and a. I calculate the values of c and a and study the operator-product structure. Higher-spin conformal spinors have no gauge invariance, admit a standard definition of c and a and can be coupled to Abelian and non-Abelian gauge fields in a renormalizable way. At the quantum level, they contribute to the one-loop beta function with the same sign as ordinary matter, admit a conformal window and non-trivial interacting fixed points. There are composite operators of high spin and low dimension, which violate the Ferrara-Gatto-Grillo theorem. Finally, other theories, such as conformal antisymmetric tensors, exhibit more severe internal problems. This research is motivated by the idea that fundamental quantum field theories should be renormalization-group (RG) interpolations between ultraviolet and infrared conformal fixed points, and quantum irreversibility should be a general principle of nature.

  5. Logarithmic conformal field theory through nilpotent conformal dimensions

    International Nuclear Information System (INIS)

    Moghimi-Araghi, S.; Rouhani, S.; Saadat, M.

    2001-01-01

    We study logarithmic conformal field theories (LCFTs) through the introduction of nilpotent conformal weights. Using this device, we derive the properties of LCFTs such as the transformation laws, singular vectors and the structure of correlation functions. We discuss the emergence of an extra energy momentum tensor, which is the logarithmic partner of the energy momentum tensor

  6. Dose conformity of gamma knife radiosurgery and risk factors for complications

    International Nuclear Information System (INIS)

    Nakamura, Jean L.; Verhey, Lynn J.; Smith, Vernon; Petti, Paula L.; Lamborn, Kathleen R.; Larson, David A.; Wara, William M.; McDermott, Michael W.; Sneed, Penny K.

    2001-01-01

    Purpose: To quantitatively evaluate dose conformity achieved using Gamma Knife radiosurgery, compare results with those reported in the literature, and evaluate risk factors for complications. Methods and Materials: All lesions treated at our institution with Gamma Knife radiosurgery from May 1993 (when volume criteria were routinely recorded) through December 1998 were reviewed. Lesions were excluded from analysis for reasons listed below. Conformity index (the ratio of prescription volume to target volume) was calculated for all evaluable lesions and for lesions comparable to those reported in the literature on conformity of linac radiosurgery. Univariate Cox regression models were used to test for associations between treatment parameters and toxicity. Results: Of 1612 targets treated in 874 patients, 274 were excluded, most commonly for unavailability of individual prescription volume data because two or more lesions were included within the same dose matrix (176 lesions), intentional partial coverage for staged treatment of large arteriovenous malformations (AVMs) (33 lesions), and missing target volume data (26 lesions). The median conformity indices were 1.67 for all 1338 evaluable lesions and 1.40-1.43 for lesions comparable to two linac radiosurgery series that reported conformity indices of 1.8 and 2.7, respectively. Among all 651 patients evaluable for complications, there were one Grade 5, eight Grade 4, and 27 Grade 3 complications. Increased risk of toxicity was associated with larger target volume, maximum lesion diameter, prescription volume, or volume of nontarget tissue within the prescription volume. Conclusions: Gamma Knife radiosurgery achieves much more conformal dose distributions than those reported for conventional linac radiosurgery and somewhat more conformal dose distributions than sophisticated linac radiosurgery techniques. Larger target, nontarget, or prescription volumes are associated with increased risk of toxicity

  7. Viscous conformal gauge theories

    DEFF Research Database (Denmark)

    Toniato, Arianna; Sannino, Francesco; Rischke, Dirk H.

    2017-01-01

    We present the conformal behavior of the shear viscosity-to-entropy density ratio and the fermion-number diffusion coefficient within the perturbative regime of the conformal window for gauge-fermion theories.......We present the conformal behavior of the shear viscosity-to-entropy density ratio and the fermion-number diffusion coefficient within the perturbative regime of the conformal window for gauge-fermion theories....

  8. Treatment planning optimization for linear accelerator radiosurgery

    International Nuclear Information System (INIS)

    Meeks, Sanford L.; Buatti, John M.; Bova, Francis J.; Friedman, William A.; Mendenhall, William M.

    1998-01-01

    Purpose: Linear accelerator radiosurgery uses multiple arcs delivered through circular collimators to produce a nominally spherical dose distribution. Production of dose distributions that conform to irregular lesions or conformally avoid critical neural structures requires a detailed understanding of the available treatment planning parameters. Methods and Materials: Treatment planning parameters that may be manipulated within a single isocenter to provide conformal avoidance and dose conformation to ellipsoidal lesions include differential arc weighting and gantry start/stop angles. More irregular lesions require the use of multiple isocenters. Iterative manipulation of treatment planning variables can be difficult and computationally expensive, especially if the effects of these manipulations are not well defined. Effects of treatment parameter manipulation are explained and illustrated. This is followed by description of the University of Florida Stereotactic Radiosurgery Treatment Planning Algorithm. This algorithm organizes the manipulations into a practical approach for radiosurgery treatment planning. Results: Iterative treatment planning parameters may be efficiently manipulated to achieve optimal treatment plans by following the University of Florida Treatment Planning Algorithm. The ability to produce conformal stereotactic treatment plans using the algorithm is demonstrated for a variety of clinical presentations. Conclusion: The standard dose distribution produced in linear accelerator radiosurgery is spherical, but manipulation of available treatment planning parameters may result in optimal dose conformation. The University of Florida Treatment Planning Algorithm organizes available treatment parameters to efficiently produce conformal radiosurgery treatment plans

  9. Conformational elasticity can facilitate TALE-DNA recognition.

    Science.gov (United States)

    Lei, Hongxing; Sun, Jiya; Baldwin, Enoch P; Segal, David J; Duan, Yong

    2014-01-01

    Sequence-programmable transcription activator-like effector (TALE) proteins have emerged as a highly efficient tool for genome engineering. Recent crystal structures depict a transition between an open unbound solenoid and more compact DNA-bound solenoid formed by the 34 amino acid repeats. How TALEs switch conformation between these two forms without substantial energetic compensation, and how the repeat-variable di-residues (RVDs) discriminate between the cognate base and other bases still remain unclear. Computational analysis on these two aspects of TALE-DNA interaction mechanism has been conducted in order to achieve a better understanding of the energetics. High elasticity was observed in the molecular dynamics simulations of DNA-free TALE structure that started from the bound conformation where it sampled a wide range of conformations including the experimentally determined apo and bound conformations. This elastic feature was also observed in the simulations starting from the apo form which suggests low free energy barrier between the two conformations and small compensation required upon binding. To analyze binding specificity, we performed free energy calculations of various combinations of RVDs and bases using Poisson-Boltzmann surface area (PBSA) and other approaches. The PBSA calculations indicated that the native RVD-base structures had lower binding free energy than mismatched structures for most of the RVDs examined. Our theoretical analyses provided new insight on the dynamics and energetics of TALE-DNA binding mechanism. © 2014 Elsevier Inc. All rights reserved.

  10. Cyndi: a multi-objective evolution algorithm based method for bioactive molecular conformational generation.

    Science.gov (United States)

    Liu, Xiaofeng; Bai, Fang; Ouyang, Sisheng; Wang, Xicheng; Li, Honglin; Jiang, Hualiang

    2009-03-31

    Conformation generation is a ubiquitous problem in molecule modelling. Many applications require sampling the broad molecular conformational space or perceiving the bioactive conformers to ensure success. Numerous in silico methods have been proposed in an attempt to resolve the problem, ranging from deterministic to non-deterministic and systemic to stochastic ones. In this work, we described an efficient conformation sampling method named Cyndi, which is based on multi-objective evolution algorithm. The conformational perturbation is subjected to evolutionary operation on the genome encoded with dihedral torsions. Various objectives are designated to render the generated Pareto optimal conformers to be energy-favoured as well as evenly scattered across the conformational space. An optional objective concerning the degree of molecular extension is added to achieve geometrically extended or compact conformations which have been observed to impact the molecular bioactivity (J Comput -Aided Mol Des 2002, 16: 105-112). Testing the performance of Cyndi against a test set consisting of 329 small molecules reveals an average minimum RMSD of 0.864 A to corresponding bioactive conformations, indicating Cyndi is highly competitive against other conformation generation methods. Meanwhile, the high-speed performance (0.49 +/- 0.18 seconds per molecule) renders Cyndi to be a practical toolkit for conformational database preparation and facilitates subsequent pharmacophore mapping or rigid docking. The copy of precompiled executable of Cyndi and the test set molecules in mol2 format are accessible in Additional file 1. On the basis of MOEA algorithm, we present a new, highly efficient conformation generation method, Cyndi, and report the results of validation and performance studies comparing with other four methods. The results reveal that Cyndi is capable of generating geometrically diverse conformers and outperforms other four multiple conformer generators in the case of

  11. Cyndi: a multi-objective evolution algorithm based method for bioactive molecular conformational generation

    Directory of Open Access Journals (Sweden)

    Li Honglin

    2009-03-01

    Full Text Available Abstract Background Conformation generation is a ubiquitous problem in molecule modelling. Many applications require sampling the broad molecular conformational space or perceiving the bioactive conformers to ensure success. Numerous in silico methods have been proposed in an attempt to resolve the problem, ranging from deterministic to non-deterministic and systemic to stochastic ones. In this work, we described an efficient conformation sampling method named Cyndi, which is based on multi-objective evolution algorithm. Results The conformational perturbation is subjected to evolutionary operation on the genome encoded with dihedral torsions. Various objectives are designated to render the generated Pareto optimal conformers to be energy-favoured as well as evenly scattered across the conformational space. An optional objective concerning the degree of molecular extension is added to achieve geometrically extended or compact conformations which have been observed to impact the molecular bioactivity (J Comput -Aided Mol Des 2002, 16: 105–112. Testing the performance of Cyndi against a test set consisting of 329 small molecules reveals an average minimum RMSD of 0.864 Å to corresponding bioactive conformations, indicating Cyndi is highly competitive against other conformation generation methods. Meanwhile, the high-speed performance (0.49 ± 0.18 seconds per molecule renders Cyndi to be a practical toolkit for conformational database preparation and facilitates subsequent pharmacophore mapping or rigid docking. The copy of precompiled executable of Cyndi and the test set molecules in mol2 format are accessible in Additional file 1. Conclusion On the basis of MOEA algorithm, we present a new, highly efficient conformation generation method, Cyndi, and report the results of validation and performance studies comparing with other four methods. The results reveal that Cyndi is capable of generating geometrically diverse conformers and outperforms

  12. Characterizing highly dynamic conformational states: The transcription bubble in RNAP-promoter open complex as an example

    Science.gov (United States)

    Lerner, Eitan; Ingargiola, Antonino; Weiss, Shimon

    2018-03-01

    Bio-macromolecules carry out complicated functions through structural changes. To understand their mechanism of action, the structure of each step has to be characterized. While classical structural biology techniques allow the characterization of a few "structural snapshots" along the enzymatic cycle (usually of stable conformations), they do not cover all (and often fast interconverting) structures in the ensemble, where each may play an important functional role. Recently, several groups have demonstrated that structures of different conformations in solution could be solved by measuring multiple distances between different pairs of residues using single-molecule Förster resonance energy transfer (smFRET) and using them as constrains for hybrid/integrative structural modeling. However, this approach is limited in cases where the conformational dynamics is faster than the technique's temporal resolution. In this study, we combine existing tools that elucidate sub-millisecond conformational dynamics together with hybrid/integrative structural modeling to study the conformational states of the transcription bubble in the bacterial RNA polymerase-promoter open complex (RPo). We measured microsecond alternating laser excitation-smFRET of differently labeled lacCONS promoter dsDNA constructs. We used a combination of burst variance analysis, photon-by-photon hidden Markov modeling, and the FRET-restrained positioning and screening approach to identify two conformational states for RPo. The experimentally derived distances of one conformational state match the known crystal structure of bacterial RPo. The experimentally derived distances of the other conformational state have characteristics of a scrunched RPo. These findings support the hypothesis that sub-millisecond dynamics in the transcription bubble are responsible for transcription start site selection.

  13. A study on quantitative analysis of field size and dose by using gating system in 4D conformal radiation treatment

    Science.gov (United States)

    Ji, Youn-Sang; Dong, Kyung-Rae; Kim, Chang-Bok; Chung, Woon-Kwan; Cho, Jae-Hwan; Lee, Hae-Kag

    2012-10-01

    This study evaluated the gating-based 4-D conformal radiation therapy (4D-CT) treatment planning by a comparison with the common 3-D conformal radiation therapy (3D-CT) treatment planning and examined the change in treatment field size and dose to the tumors and adjacent normal tissues because an unnecessary dose is also included in the 3-D treatment planning for the radiation treatment of tumors in the chest and abdomen. The 3D-CT and gating-based 4D-CT images were obtained from patients who had undergone radiation treatment for chest and abdomen tumors in the oncology department. After establishing a treatment plan, the CT treatment and planning system were used to measure the change in field size for analysis. A dose volume histogram (DVH) was used to calculate the appropriate dose to planning target volume (PTV) tumors and adjacent normal tissue. The difference in the treatment volume of the chest was 0.6 and 0.83 cm on the X- and Y-axis, respectively, for the gross tumor volume (GTV). Accordingly, the values in the 4D-CT treatment planning were smaller and the dose was more concentrated by 2.7% and 0.9% on the GTV and clinical target volume (CTV), respectively. The normal tissues in the surrounding normal tissues were reduced by 3.0%, 7.2%, 0.4%, 1.7%, 2.6% and 0.2% in the bronchus, chest wall, esophagus, heart, lung and spinal cord, respectively. The difference in the treatment volume of the abdomen was 0.72 cm on the X-axis and 0.51 cm on the Y-axis for the GTV; and 1.06 cm on the X-axis and 1.85 cm on the Y-axis for the PTV. Therefore, the values in the 4D-CT treatment planning were smaller. The dose was concentrated by 6.8% and 4.3% on the GTV and PTV, respectively, whereas the adjacent normal tissues in the cord, Lt. kidney, Rt. kidney, small bowels and whole liver were reduced by 3.2%, 4.2%, 1.5%, 6.2% and 12.7%, respectively. The treatment field size was smaller in volume in the case of the 4D-CT treatment planning. In the DVH, the 4D-CT treatment

  14. Conformal invariance in supergravity

    International Nuclear Information System (INIS)

    Bergshoeff, E.A.

    1983-01-01

    In this thesis the author explains the role of conformal invariance in supergravity. He presents the complete structure of extended conformal supergravity for N <= 4. The outline of this work is as follows. In chapter 2 he briefly summarizes the essential properties of supersymmetry and supergravity and indicates the use of conformal invariance in supergravity. The idea that the introduction of additional symmetry transformations can make clear the structure of a field theory is not reserved to supergravity only. By means of some simple examples it is shown in chapter 3 how one can always introduce additional gauge transformations in a theory of massive vector fields. Moreover it is shown how the gauge invariant formulation sometimes explains the quantum mechanical properties of the theory. In chapter 4 the author defines the conformal transformations and summarizes their main properties. He explains how these conformal transformations can be used to analyse the structure of gravity. The supersymmetric extension of these results is discussed in chapter 5. Here he describes as an example how N=1 supergravity can be reformulated in a conformally-invariant way. He also shows that beyond N=1 the gauge fields of the superconformal symmetries do not constitute an off-shell field representation of extended conformal supergravity. Therefore, in chapter 6, a systematic method to construct the off-shell formulation of all extended conformal supergravity theories with N <= 4 is developed. As an example he uses this method to construct N=1 conformal supergravity. Finally, in chapter 7 N=4 conformal supergravity is discussed. (Auth.)

  15. DNA oligonucleotide conformations: high resolution NMR studies

    International Nuclear Information System (INIS)

    Mellema, J.-R.

    1984-01-01

    The present work describes a DNA double-helix model, which is well comparable with the models derived from fibre-diffraction studies. The model has a mononucleotide repeat with torsion angles in accordance with average geometries as derived from 1 H NMR studies. Special attention was paid to reduce the number of short H-H nonbonding contacts, which are abundantly present in the 'classical' fibre-diffraction models. Chapter 3 describes the first complete assignment of a 1 H NMR spectrum of a DNA tetramer, d(TAAT). Preliminary conformational data derived from the spectral parameters recorded at 27 0 C are given. A more detailed analysis employing temperature-dependence studies is given in Chapter 4. (Auth.)

  16. Rectal dose sparing with a balloon catheter and ultrasound localization in conformal radiation therapy for prostate cancer

    International Nuclear Information System (INIS)

    Patel, Rakesh R.; Orton, Nigel; Tome, Wolfgang A.; Chappell, Rick; Ritter, Mark A.

    2003-01-01

    Background and purpose: To compare the rectal wall and bladder volume in the high dose region with or without the use of a balloon catheter with both three-dimensional (3D)-conformal and intensity modulated radiation therapy (CRT, IMRT) approaches in the treatment of prostate cancer. Material and methods: Five patients with a wide range of prostate volumes and treated with primary external beam radiation therapy for localized prostate cancer were selected for analysis. Pinnacle TM treatment plans were generated utilizing a 3D conformal six-field design and an IMRT seven coplanar-field plan with a novel, three-step optimization and with ultrasound localization. Separate plans were devised with a rectal balloon deflated or air inflated with and without inclusion of the seminal vesicles (SV) in the target volume. The prescription dose was 76 Gy in 38 fractions of 2 Gy each. Cumulative dose-volume histograms (DVHs) were analyzed for the planning target volume (PTV), rectal wall, and bladder with an inflated (60 cc air) or deflated balloon with and without SV included. The volumes of rectal wall and bladder above 60, 65, and 70 Gy with each treatment approach were evaluated. Results: Daily balloon placement was well-tolerated with good patient positional reproducibility. Inflation of the rectal balloon in all cases resulted in a significant decrease in the absolute volume of rectal wall receiving greater than 60, 65, or 70 Gy. The rectal sparing ratio (RSR), consisting of a structure's high dose volume with the catheter inflated, divided by the volume with the catheter deflated, was calculated for each patient with and without seminal vesicle inclusion for 3D-CRT and IMRT. For 3D-CRT, RSRs with SV included were 0.59, 0.59, and 0.56 and with SV excluded were 0.60, 0.58, and 0.54 at doses of greater than 60, 65, and 70 Gy, respectively. Similarly, for IMRT, the mean RSRs were 0.59, 0.59, and 0.63 including SV and 0.71, 0.66, and 0.67 excluding SV at these same dose levels

  17. High energy physics signatures from inflation and conformal symmetry of de Sitter

    International Nuclear Information System (INIS)

    Kehagias, A.; Riotto, A.

    2015-01-01

    During inflation, the geometry of spacetime is described by a (quasi-)de Sitter phase. Inflationary observables are determined by the underlying (softly broken) de Sitter isometry group SO(1, 4) which acts like a conformal group on R 3 : when the fluctuations are on super-Hubble scales, the correlators of the scalar fields are constrained by conformal invariance. Heavy fields with mass m larger than the Hubble rate H correspond to operators with imaginary dimensions in the dual Euclidean three-dimensional conformal field theory. By making use of the dS/CFT correspondence we show that, besides the Boltzmann suppression expected from the thermal properties of de Sitter space, the generic effect of heavy fields in the inflationary correlators of the light fields is to introduce power-law suppressed corrections of the form O(H 2 / m 2 ). This can be seen, for instance, at the level of the four-point correlator for which we provide the correction due to a massive scalar field exchange. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Conformational determinants of phosphotyrosine peptides complexed with the Src SH2 domain.

    Directory of Open Access Journals (Sweden)

    Joseph Nachman

    2010-06-01

    Full Text Available The inhibition of specific SH2 domain mediated protein-protein interactions as an effective chemotherapeutic approach in the treatment of diseases remains a challenge. That different conformations of peptide-ligands are preferred by different SH2 domains is an underappreciated observation from the structural analysis of phosphotyrosine peptide binding to SH2 domains that may aid in future drug design. To explore the nature of ligand binding, we use simulated annealing (SA to sample the conformational space of phosphotyrosine-containing peptides complexed with the Src SH2 domain. While in good agreement with the crystallographic and NMR studies of high-affinity phosphopeptide-SH2 domain complexes, the results suggest that the structural basis for phopsphopeptide- Src SH2 interactions is more complex than the "two-pronged plug two-hole socket" model. A systematic study of peptides of type pYEEX, where pY is phosphotyrosine and X is a hydrophobic residue, indicates that these peptides can assume two conformations, one extended and one helical, representing the balance between the interaction of residue X with the hydrophobic hole on the surface of the Src SH2 domain, and its contribution to the inherent tendency of the two glutamic acids to form an alpha-helix. In contrast, a beta-turn conformation, almost identical to that observed in the crystal structure of pYVNV bound to the Grb2 SH2 domain, predominates for pYXNX peptides, even in the presence of isoleucine at the third position. While peptide binding affinities, as measured by fluorescence polarization, correlate with the relative proportion of extended peptide conformation, these results suggest a model where all three residues C-terminal to the phosphotyrosine determine the conformation of the bound phosphopeptide. The information obtained in this work can be used in the design of specific SH2 domain inhibitors.

  19. Conformal intensity-modulated radiotherapy (IMRT) delivered by robotic linac-conformality versus efficiency of dose delivery

    International Nuclear Information System (INIS)

    Webb, Steve

    2000-01-01

    Intensity-modulated radiotherapy (IMRT) may be delivered with a high-energy-photon linac mounted on a robotic gantry and executing a complex trajectory. In a previous paper an inverse-planning technique was developed for such an application. Here the work is extended to demonstrate the dependence of conformality on the size of the elemental pencil beam, on the complexity of the trajectory and on the sampling of azimuth and elevation of the collimated source. The improved conformality of complex trajectories is demonstrated and benchmarked relative to simpler trajectories, more representative of existing non-robotic IMRT techniques. Specifically, by choosing a very fine pencil beam, exquisitely conformal dose distributions have been obtained. Important sampling considerations have been determined. Expressions have been derived for the dosimetry and monitor-unit efficiency of robotic IMRT. Equivalent trajectories were computed for executing the complex robotic trajectories instead by using a conventional linac. The work benchmarks an ideal in IMRT against which more practical and more common techniques may be measured. (author)

  20. Transcatheter closure of patent ductus arteriosus with special conformation

    International Nuclear Information System (INIS)

    Zhang Yigang; Li Shijie; Fu Qiang

    2009-01-01

    Objective: To discuss the technique of transcatheter closure for the treatment of patent ductus arteriosus (PDA) with special conformation so as to improve the technical success rate and clinical safety. Methods: Transcatheter closure was performed in 23 patients with PDA of special types by using different devices according to the angiocardiographic conformation and the clinical manifestation. The therapeutic results were evaluated by transthoracic color Doppler echocardiography at 24 hours, one, three and six months after the operation. Results: Different occluders were successfully implanted in all patients. PDA of special types was found in 23 patients, which included: (1) special conformation (n=12), consisting of small type (n=5), huge type (n=3), aneurismal type (n=2) and displayed on special exposure position (n=2), (2) accompanied by other malformations (n=2), containing dextroaortic arch (n=1) and dextrocardia (n=1), (3) associated with severe pulmonary hypertension (n=8) and (4) recanalization after surgery (n=1). Conclusion: For PDA with special conformation, therapeutic strategy should be individually formulated in order to smoothly bring the closure procedure to success. (authors)

  1. Irreversibility and higher-spin conformal field theory

    CERN Document Server

    Anselmi, D

    2000-01-01

    I discuss the idea that quantum irreversibility is a general principle of nature and a related "conformal hypothesis", stating that all fundamental quantum field theories should be renormalization-group (RG) interpolations between ultraviolet and infrared conformal fixed points. In particular, the Newton constant should be viewed as a low-energy effect of the RG scale. This approach leads naturally to consider higher-spin conformal field theories, which are here classified, as candidate high-energy theories. Bosonic conformal tensors have a positive-definite action, equal to the square of a field strength, and a higher-derivative gauge invariance. The central charges c and a are well defined and positive. I calculate their values and study the operator-product structure. Fermionic theories have no gauge invariance and can be coupled to Abelian and non-Abelian gauge fields in a renormalizable way. At the quantum level, they contribute to the one-loop beta function with the same sign as ordinary matter, admit a...

  2. Independent dose calculation of the Tps Iplan in radiotherapy conformed with MLC

    International Nuclear Information System (INIS)

    Adrada, A.; Tello, Z.; Medina, L.; Garrigo, E.; Venencia, D.

    2014-08-01

    The systems utilization of independent dose calculation in three dimensional-Conformal Radiation Therapy (3D-Crt) treatments allows a direct verification of the treatments times. The utilization of these systems allows diminishing the probability of errors occurrence generated by the treatment planning system (Tps), allowing a detailed analysis of the dose to delivering and review of the normalization point (Np) or prescription. The independent dose calculation is realized across the knowledge of dosimetric parameters of the treatment machine and particular characteristics of every individual field. The aim of this work is develops a calculation system of punctual doses for isocentric fields conformed with multi-leaf collimation systems (MLC), where the dose calculation is in conformity with the suggested ones by ICRU Report No. 42, 1987. Calculation software was realized in C ++ under a free platform of programming (Code::Blocks). The system uses files in format Rtp, exported from the Tps to systems of record and verification (Lantis). This file contains detailed information of the dose, Um, position of the MLC sheets and collimators for every field of treatment. The size of equivalent field is obtained from the positions of every sheet; the effective depth of calculation can be introduced from the dosimetric report of the Tps or automatically from the DFS of the field. The 3D coordinates of the isocenter and the Np for the treatment plan must be introduced manually. From this information the system looks the dosimetric parameters and calculates the Um. The calculations were realized in two accelerators a NOVALIS Tx (Varian) with 120 sheets of high definition (hd-MLC) and a PRIMUS Optifocus (Siemens) with 82 sheets. 705 patients were analyzed for a total of 1082, in plans made for both equipment s, the average uncertainty with regard to the calculation of the Tps is-0.43% ± 2.42% in a range between [-7.90 %, 7.50 %]. The major uncertainty was in Np near of the

  3. Comparative study of four advanced 3d-conformal radiation therapy treatment planning techniques for head and neck cancer

    International Nuclear Information System (INIS)

    Herrassi, Mohamed Yassine; Bentayeb, Farida; Malisan, Maria Rosa

    2013-01-01

    For the head-and-neck cancer bilateral irradiation, intensity-modulated radiation therapy (IMRT) is the most reported technique as it enables both target dose coverage and organ-at-risk (OAR) sparing. However, during the last 20 years, three-dimensional conformal radiotherapy (3DCRT) techniques have been introduced, which are tailored to improve the classic shrinking field technique, as regards both planning target volume (PTV) dose conformality and sparing of OARs, such as parotid glands and spinal cord. In this study, we tested experimentally in a sample of 13 patients, four of these advanced 3DCRT techniques, all using photon beams only and a unique isocentre, namely Bellinzona, Forward-Planned Multisegments (FPMS), ConPas, and field-in-field (FIF) techniques. Statistical analysis of the main dosimetric parameters of PTV and OARs DVHs as well as of homogeneity and conformity indexes was carried out in order to compare the performance of each technique. The results show that the PTV dose coverage is adequate for all the techniques, with the FPMS techniques providing the highest value for D95%; on the other hand, the best sparing of parotid glands is achieved using the FIF and ConPas techniques, with a mean dose of 26 Gy to parotid glands for a PTV prescription dose of 54 Gy. After taking into account both PTV coverage and parotid sparing, the best global performance was achieved by the FIF technique with results comparable to that of IMRT plans. This technique can be proposed as a valid alternative when IMRT equipment is not available or patient is not suitable for IMRT treatment. (author)

  4. Conformal Organohalide Perovskites Enable Lasing on Spherical Resonators

    KAUST Repository

    Sutherland, Brandon R.

    2014-10-28

    © 2014 American Chemical Society. Conformal integration of semiconductor gain media is broadly important in on-chip optical communication technology. Here we deploy atomic layer deposition to create conformally deposited organohalide perovskites-an attractive semiconducting gain medium-with the goal of achieving coherent light emission on spherical optical cavities. We demonstrate the high quality of perovskite gain media fabricated with this method, achieving optical gain in the nanosecond pulse regime with a threshold for amplified spontaneous emission of 65 ± 8 μJ cm-2. Through variable stripe length measurements, we report a net modal gain of 125 ± 22 cm-1 and a gain bandwidth of 50 ± 14 meV. Leveraging the high quality of the gain medium, we conformally coat silica microspheres with perovskite to form whispering gallery mode optical cavities and achieve lasing.

  5. Conformal expansions and renormalons

    Energy Technology Data Exchange (ETDEWEB)

    Rathsman, J.

    2000-02-07

    The coefficients in perturbative expansions in gauge theories are factorially increasing, predominantly due to renormalons. This type of factorial increase is not expected in conformal theories. In QCD conformal relations between observables can be defined in the presence of a perturbative infrared fixed-point. Using the Banks-Zaks expansion the authors study the effect of the large-order behavior of the perturbative series on the conformal coefficients. The authors find that in general these coefficients become factorially increasing. However, when the factorial behavior genuinely originates in a renormalon integral, as implied by a postulated skeleton expansion, it does not affect the conformal coefficients. As a consequence, the conformal coefficients will indeed be free of renormalon divergence, in accordance with previous observations concerning the smallness of these coefficients for specific observables. The authors further show that the correspondence of the BLM method with the skeleton expansion implies a unique scale-setting procedure. The BLM coefficients can be interpreted as the conformal coefficients in the series relating the fixed-point value of the observable with that of the skeleton effective charge. Through the skeleton expansion the relevance of renormalon-free conformal coefficients extends to real-world QCD.

  6. Comprehensive irradiation of head and neck cancer using conformal multisegmental fields: assessment of target coverage and noninvolved tissue sparing

    International Nuclear Information System (INIS)

    Eisbruch, Avraham; Marsh, Lon H.; Martel, Mary K.; Ship, Jonathan A.; Haken, Randall ten; Pu, Anthony T.; Fraass, Benedick A.; Lichter, Allen S.

    1998-01-01

    Purpose: Conformal treatment using static multisegmental intensity modulation was developed for patients requiring comprehensive irradiation for head and neck cancer. The major aim is sparing major salivary gland function while adequately treating the targets. To assess the adequacy of the conformal plans regarding target coverage and dose homogeneity, they were compared with standard irradiation plans. Methods and Materials: Fifteen patients with stage III/IV head and neck cancer requiring comprehensive, bilateral neck irradiation participated in this study. CT-based treatment plans included five to six nonopposed fields, each having two to four in-field segments. Fields and segments were devised using beam's eye views of the planning target volumes (PTVs), noninvolved organs, and isodose surfaces, to achieve homogeneous dose distribution that encompassed the targets and spared major salivary gland tissue. For comparison, standard three-field radiation plans were devised retrospectively for each patient, with the same CT-derived targets used for the clinical (conformal) plans. Saliva flow rates from each major salivary gland were measured before and periodically after treatment. Results: On average, the minimal dose to the primary PTVs in the conformal plans [95.2% of the prescribed dose, standard deviation (SD) 4%] was higher than in the standard plans (91%, SD 7%; p = 0.02), and target volumes receiving <95% or <90% of the prescribed dose were smaller in the conformal plans (p = 0.004 and 0.02, respectively). Similar advantages of the conformal plans compared to standard plans were found in ipsilateral jugular nodes PTV coverage. The reason for underdosing in the standard treatment plans was primarily failure of electron beams to fully encompass targets. No significant differences were found in contralateral jugular or posterior neck nodes coverage. The minimal dose to the retropharyngeal nodes was higher in the standard plans. However, all conformal plans

  7. Antibiotic Conformity with Culture Results of Hospitalized Pneumonia Patients in Melati Ward at Dr. Hasan Sadikin General Hospital Bandung, Indonesia

    Directory of Open Access Journals (Sweden)

    Randhi Rinaldi

    2016-12-01

    Full Text Available Background: Pneumonia is an infection with the highest mortality rate in Indonesian hospitals. According to The American Thoracic Society and The Infectious Diseases Society of America (ATS/IDSA, empirical use of antibiotics is still effective for pneumonia treatment. Inappropriate use of antibiotics would cause negative effects such as prolonged hospitalization, a high cost of treatment, and increased antibiotic-resistant bacteria. The goal of this study was to clarify the empirical use of antibiotic conformity with a bacteria culture. Methods: This study was conducted from August to October 2013 using a descriptive retrospective method based on 116 medical records of pneumonia patients hospitalized in Melati Ward, Dr. Hasan Sadikin General Hospital Bandung during 2011–2012. The type of bacteria, conformity with antibiotics given to patients, and type of antibiotics were analyzed. The conformity of antibiotics was assessed based on the resistance test. If the results were sensitive, they would be put in the conforming group and in the non-conforming group if the results were resistant or intermediate. Data was derived with descriptive statistics, using percentage and frequency distribution, illustrated in tables and figures. Results: Based on culture results and sensitivity of antibiotic empirical therapy given, 55.17% cases were conformed. The most widely used antibiotic group was Third-generation Cephalosporin (60.34%. The most common bacterias were Klebsiella pneumonia (34.5% and Acinetobacter baumanni (13.8%. Conclusions: Most of the antibiotics given to pneumonia patients are still appropriate with results of the bacteria culture test and resistance test.

  8. Effects of high pressure homogenization on the activity, stability, kinetics and three-dimensional conformation of a glucose oxidase produced by Aspergillus niger.

    Directory of Open Access Journals (Sweden)

    Alline Artigiani Lima Tribst

    Full Text Available High pressure homogenization (HPH is a non-thermal method, which has been employed to change the activity and stability of biotechnologically relevant enzymes. This work investigated how HPH affects the structural and functional characteristics of a glucose oxidase (GO from Aspergillus niger. The enzyme was homogenized at 75 and 150 MPa and the effects were evaluated with respect to the enzyme activity, stability, kinetic parameters and molecular structure. The enzyme showed a pH-dependent response to the HPH treatment, with reduction or maintenance of activity at pH 4.5-6.0 and a remarkable activity increase (30-300% at pH 6.5 in all tested temperatures (15, 50 and 75°C. The enzyme thermal tolerance was reduced due to HPH treatment and the storage for 24 h at high temperatures (50 and 75°C also caused a reduction of activity. Interestingly, at lower temperatures (15°C the activity levels were slightly higher than that observed for native enzyme or at least maintained. These effects of HPH treatment on function and stability of GO were further investigated by spectroscopic methods. Both fluorescence and circular dichroism revealed conformational changes in the molecular structure of the enzyme that might be associated with the distinct functional and stability behavior of GO.

  9. MUFASA: the strength and evolution of galaxy conformity in various tracers

    Science.gov (United States)

    Rafieferantsoa, Mika; Davé, Romeel

    2018-03-01

    We investigate galaxy conformity using the MUFASA cosmological hydrodynamical simulation. We show a bimodal distribution in galaxy colour with radius, albeit with too many low-mass quenched satellite galaxies compared to observations. MUFASA produces conformity in observed properties such as colour, specific star formation rate (sSFR), and H I content, i.e. neighbouring galaxies have similar properties. We see analogous trends in other properties such as in environment, stellar age, H2 content, and metallicity. We introduce quantifying conformity using S(R), measuring the relative difference in upper and lower quartile properties of the neighbours. We show that low-mass and non-quenched haloes have weak conformity (S(R)≲ 0.5) extending to large projected radii R in all properties, while high-mass and quenched haloes have strong conformity (S(R)˜ 1) that diminishes rapidly with R and disappears at R ≳ 1 Mpc. S(R) is strongest for environment in low-mass haloes, and sSFR (or colour) in high-mass haloes, and is dominated by one-halo conformity with the exception of H I in small haloes. Metallicity shows a curious anticonformity in massive haloes. Tracking the evolution of conformity for z = 0 galaxies back in time shows that conformity broadly emerges as a late-time (z ≲ 1) phenomenon. However, for fixed halo mass bins, conformity is fairly constant with redshift out to z ≳ 2. These trends are consistent with the idea that strong conformity only emerges once haloes grow above MUFASA's quenching mass scale of ˜1012 M⊙. A quantitative measure of conformity in various properties, along with its evolution, thus represents a new and stringent test of the impact of quenching on environment within current galaxy formation models.

  10. 3-D conformal HDR brachytherapy as monotherapy for localized prostate cancer. A pilot study

    International Nuclear Information System (INIS)

    Martin, T.; Baltas, D.; Kurek, R.; Roeddiger, S.; Kontova, M.; Anagnostopoulos, G.; Skazikis, G.; Zamboglou, N.; Dannenberg, T.; Buhleier, T.; Tunn, U.

    2004-01-01

    Purpose: pilot study to evaluate feasibility, acute toxicity and conformal quality of three-dimensional (3-D) conformal high-dose-rate (HDR) brachytherapy as monotherapy for localized prostate cancer using intraoperative real-time planning. Patients and methods: between 05/2002 and 05/2003, 52 patients with prostate cancer, prostate-specific antigen (PSA) ≤ 10 ng/ml, Gleason score ≤ 7 and clinical stage ≤ T2a were treated. Median PSA was 6.4 ng/ml and median Gleason score 5. 24/52 patients had stage T1c and 28/52 stage T2a. For transrectal ultrasound-(TRUS-)guided transperineal implantation of flexible plastic needles into the prostate, the real-time HDR planning system SWIFT trademark was used. After implantation, CT-based 3-D postplanning was performed. All patients received one implant for four fractions of HDR brachytherapy in 48 h using a reference dose (D ref ) of 9.5 Gy to a total dose of 38.0 Gy. Dose-volume histograms (DVHs) were analyzed to evaluate the conformal quality of each implant using D 90 , D 10 urethra, and D 10 rectum. Acute toxicity was evaluated using the CTC (common toxicity criteria) scales. Results: median D 90 was 106% of D ref (range: 93-115%), median D 10 urethra 159% of D ref (range: 127-192%), and median D 10 rectum 55% of D ref (range: 35-68%). Median follow-up is currently 8 months. In 2/52 patients acute grade 3 genitourinary toxicity was observed. No gastrointestinal toxicity > grade 1 occurred. Conclusion: 3-D conformal HDR brachytherapy as monotherapy using intraoperative real-time planning is a feasible and highly conformal treatment for localized prostate cancer associated with minimal acute toxicity. Longer follow-up is needed to evaluate late toxicity and biochemical control. (orig.)

  11. Biological Modeling Based Outcome Analysis (BMOA) in 3D Conformal Radiation Therapy (3DCRT) Treatments for Lung and Breast Cancers

    Science.gov (United States)

    Pyakuryal, Anil; Chen, Chiu-Hao; Dhungana, Sudarshan

    2010-03-01

    3DCRT treatments are the most commonly used techniques in the treatment of lung and breast cancers. The purpose of this study was to perform the BMOA of the 3DCRT plans designed for the treatment of breast and lung cancers utilizing HART program (Med. Phys. 36, p.2547(2009)). The BMOA parameters include normal tissue complication probability (NTCP), tumor control probability (TCP), and the complication-free tumor control probability (P+). The 3DCRT plans were designed for (i) the palliative treatment of 8 left lung cancer patients (CPs) at early stage (m=8), (ii) the curative treatment of 8 left lung CPs at stages II and III (k=8), and (iii) the curative treatment of 8 left breast CPs (n=8). The NTCPs were noticeably small (esophagus in lung CPs (k=8). Assessments of the TCPs and P+s also indicated good improvements in local tumor control in all plans. Homogeneous target coverage and improved dose conformality were the major advantages of such techniques in the treatment of breast cancer. These achievements support the efficacy of the 3DCRT techniques for the efficient treatment of various types of cancer.

  12. Treatment of primany hepatic carcinoma with three-dimensional conformal radiation therapy combined with transcatheter arterial chemoembolization

    International Nuclear Information System (INIS)

    Wu Li; Wen Xiaoping; Huang Wei

    2006-01-01

    Objective: To evaluate the effects of three-dimensional conformal radiation therapy (3DCRT) combined with transcatheter arterial chemoembolization (TACE) on stage m/IV primary hepatic carcinoma. Methods: Eighty cases of stage III/IV primary hepatic carcinoma were randomly divided into two groups: 40 cases treated with three-dimensional conformal radiation therapy combined with transcatheter arterial chemoembolization (3DCRT + TACE group) and 40 cases treated with three-dimensional conformal radiation therapy associated with hepatic arterial infusion chemotherapy (3DCRT +HAI group). Results: The response rates were 75% and 45% in 3DCRT + TACE group and 3DCRT + HAI group, respectively; and the difference between the two groups was statistically significant (P 0.05), The 0.5-, 1- and 2-year survival rates were 73% , 45% and 28% in 3DCRT + TACE group, and 45%, 25% and 13% in 3DCRT + HAI group, respectively; and the difference between the two groups was statistically significant (P 0.05). Conclusion: Three-dimensional conformal radiation therapy combined with transcatheter arterial chemoembolization improved prognosis of stage III/IV primary hepatic carcinoma. (authors)

  13. A computer-controlled high resolution micro-multi-leaf collimator for stereotactic conformal radio-therapy

    International Nuclear Information System (INIS)

    Schlegel, Wolfgang; Pastyr, Otto; Kubesch, Rudolf; Diemer, Torsten; Kuester, Gunnilla; Rhein, Bernhard; Hoever, Karl-Heinz

    1997-01-01

    Purpose/Objective In stereotactic conformal radiotherapy of irregularly shaped lesions, either multi-isocentric convergent beam treatment techniques with circular collimators or irregular shaped beams are being used. While the treatment technique with multiple isocenters has the disadvantage of producing inhomogeneous dose distributions, the use of irregular shaped fields is not yet satisfying from a technical point of view: Cerrobend blocking or the use of static micro MLCs need a long preparation time and only allow static treatment techniques, MLC collimators which are commercially available in connection with modern LINACs have leaf-thickness of at least 1 cm which is too coarse for stereotactic radiotherapy of lesions in the brain and head and neck area. For this reason, we developed a computer controlled micro-MLC with technical specifications matched to the needs of stereotactic radiotherapy and radiosurgery. Materials and Methods The mechanical specifications of the computer controlled micro-MLC were derived from our experience with stereotactic treatment techniques, from the requirement that the MLC has to be attachable as an external device to the accessory holders of standard LINACs, including cost considerations, dosimetric measurements as well as Monte Carlo calculations. The Micro-MLC is controlled by an electronic equipment consisting of a standard PC under Windows 95, an interface board, 14 Micro-controller boards, a verification system and 80 driving units equipped with DC motors and potentiometers. The control program has calibrating, operating, visualizing and test options. Irregular field data are transferred from the treatment planning computer to the control PC and distributed to the micro-controllers, which in parallel are driving three leaves each. Beside the special control unit, we are currently investigating whether the electronics of commercially available integrated large field MLCs can also be used for operating the Micro-MLC. Results

  14. The conformal method and the conformal thin-sandwich method are the same

    International Nuclear Information System (INIS)

    Maxwell, David

    2014-01-01

    The conformal method developed in the 1970s and the more recent Lagrangian and Hamiltonian conformal thin-sandwich methods are techniques for finding solutions of the Einstein constraint equations. We show that they are manifestations of a single conformal method: there is a straightforward way to convert back and forth between the parameters for these methods so that the corresponding solutions of the Einstein constraint equations agree. The unifying idea is the need to clearly distinguish tangent and cotangent vectors to the space of conformal classes on a manifold, and we introduce a vocabulary for working with these objects without reference to a particular representative background metric. As a consequence of these conceptual advantages, we demonstrate how to strengthen previous near-CMC (constant mean curvature) existence and non-existence theorems for the original conformal method to include metrics with scalar curvatures that change sign. (paper)

  15. How Diverse are the Protein-Bound Conformations of Small-Molecule Drugs and Cofactors?

    Science.gov (United States)

    Friedrich, Nils-Ole; Simsir, Méliné; Kirchmair, Johannes

    2018-03-01

    Knowledge of the bioactive conformations of small molecules or the ability to predict them with theoretical methods is of key importance to the design of bioactive compounds such as drugs, agrochemicals and cosmetics. Using an elaborate cheminformatics pipeline, which also evaluates the support of individual atom coordinates by the measured electron density, we compiled a complete set (“Sperrylite Dataset”) of high-quality structures of protein-bound ligand conformations from the PDB. The Sperrylite Dataset consists of a total of 10,936 high-quality structures of 4548 unique ligands. Based on this dataset, we assessed the variability of the bioactive conformations of 91 small molecules—each represented by a minimum of ten structures—and found it to be largely independent of the number of rotatable bonds. Sixty-nine molecules had at least two distinct conformations (defined by an RMSD greater than 1 Å). For a representative subset of 17 approved drugs and cofactors we observed a clear trend for the formation of few clusters of highly similar conformers. Even for proteins that share a very low sequence identity, ligands were regularly found to adopt similar conformations. For cofactors, a clear trend for extended conformations was measured, although in few cases also coiled conformers were observed. The Sperrylite Dataset is available for download from http://www.zbh.uni-hamburg.de/sperrylite_dataset.

  16. Clinical Studies on conformal radiotherapy combined with epidermal ...

    African Journals Online (AJOL)

    Purpose: To study the effect of conformal radiotherapy combined with epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) in the second-line treatment of non-small cell lung cancer (NSCLC). Methods: A total of 316 patients attending Shanghai Pulmonary Hospital affiliated to Tongji University, were divided ...

  17. Boundary conformal field theory and the worldsheet approach to D-branes

    CERN Document Server

    Recknagel, Andreas

    2013-01-01

    Boundary conformal field theory is concerned with a class of two-dimensional quantum field theories which display a rich mathematical structure and have many applications ranging from string theory to condensed matter physics. In particular, the framework allows discussion of strings and branes directly at the quantum level. Written by internationally renowned experts, this comprehensive introduction to boundary conformal field theory reaches from theoretical foundations to recent developments, with an emphasis on the algebraic treatment of string backgrounds. Topics covered include basic concepts in conformal field theory with and without boundaries, the mathematical description of strings and D-branes, and the geometry of strongly curved spacetime. The book offers insights into string geometry that go beyond classical notions. Describing the theory from basic concepts, and providing numerous worked examples from conformal field theory and string theory, this reference is of interest to graduate students and...

  18. Social anxiety and heavy situational drinking: coping and conformity motives as multiple mediators.

    Science.gov (United States)

    Terlecki, Meredith A; Buckner, Julia D

    2015-01-01

    Individuals with clinically elevated social anxiety are at greater risk for alcohol use disorder, and the relation between social anxiety and drinking problems is at least partially accounted for by drinking more in negative emotional (e.g., feeling sad or angry) and personal/intimate (e.g., before sexual intercourse) situations. Identification of cognitive/motivational factors related to drinking in these high-risk situations could inform the development of treatment and prevention interventions for these high-risk drinkers. The current cross-sectional study examined the mediating effect of drinking motives on the relationship between social anxiety and drinking these high-risk situations among undergraduates (N=232). Clinically elevated social anxiety was associated with greater coping and conformity motives. Both coping and conformity motives mediated the relation between social anxiety and heavier alcohol consumption in negative emotional and personal/intimate contexts. Multiple mediation analyses indicated that these motives work additively to mediate the social anxiety-drinking situations relationship, such that heavy situational drinking among undergraduates with clinically elevated social anxiety can be jointly attributed to desire to cope with negative affect and to avoid social scrutiny. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Superspace conformal field theory

    Energy Technology Data Exchange (ETDEWEB)

    Quella, Thomas [Koeln Univ. (Germany). Inst. fuer Theoretische Physik; Schomerus, Volker [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-07-15

    Conformal sigma models and WZW models on coset superspaces provide important examples of logarithmic conformal field theories. They possess many applications to problems in string and condensed matter theory. We review recent results and developments, including the general construction of WZW models on type I supergroups, the classification of conformal sigma models and their embedding into string theory.

  20. Superspace conformal field theory

    International Nuclear Information System (INIS)

    Quella, Thomas

    2013-07-01

    Conformal sigma models and WZW models on coset superspaces provide important examples of logarithmic conformal field theories. They possess many applications to problems in string and condensed matter theory. We review recent results and developments, including the general construction of WZW models on type I supergroups, the classification of conformal sigma models and their embedding into string theory.

  1. Conformal radiotherapy in the adjuvant treatment of gastric cancer: Review of 82 cases

    International Nuclear Information System (INIS)

    Kassam, Zahra; Lockwood, Gina; O'Brien, Catherine; Brierley, James; Swallow, Carol; Oza, Amit; Siu, Lillian; Knox, Jennifer J.; Wong, Rebecca; Cummings, Bernard; Kim, John; Moore, Malcolm; Ringash, Jolie

    2006-01-01

    Background: The Intergroup 0116 study showed a survival benefit with adjuvant chemoradiotherapy (CRT) for resected gastric cancer. We report our experience using conformal radiotherapy (RT). Methods and Materials: Eighty-two patients with resected gastric or gastroesophageal junction (GEJ) adenocarcinoma, Stage IB to IV (M0), were treated with 45 Gy in 25 fractions using a 5-field conformal technique. Chemotherapy was in accordance with the Intergroup 0116 study, or infusional 5-fluorouracil and cisplatin in a phase I/II trial. Results: Mean age was 56.4 years. Median follow-up was 22.8 months. Grade 3 or greater acute toxicity (National Cancer Institute Common Terminology Criteria of Adverse Events, version 3.0) was noted in 57% of patients (upper gastrointestinal tract 34%, hematologic 33%). One patient died of neutropenic sepsis. Radiation Therapy Oncology Group Grade 3 late toxicity included esophageal strictures (3 patients) and small bowel obstruction (1 patient). Full course CRT was completed by 67% of patients. Of 26 patients who relapsed, 20 died. Site of first relapse was available on 23 patients: 8 locoregional and distant, 4 locoregional alone, 11 distant alone. Overall and relapse-free survival were 69% and 54% at 3 years. Conclusion: Adjuvant CRT for gastric cancer, even with conformal RT, is associated with significant toxicity. Survival was comparable to that reported in the Intergroup 0116 study

  2. Brainstem tolerance to conformal radiotherapy of skull base tumors

    International Nuclear Information System (INIS)

    Debus, J.; Hug, E.B.; Munzenrider, J.E.; Liebsch, N.J.; O'Farrell, D.; Efird, J.; Daly, W.; Suit, H.D.

    1996-01-01

    Purpose/Objective: Brainstem tolerance to inhomogenous radiation doses applied by modern conformal radiotherapy has not yet been examined. The aim of this study was to analyse the incidence of brainstem toxicity in patients treated for skull base tumors with high dose conformal radiotherapy. Materials and Methods: Between 1974 and 1995, 367 patients with chordomas (n=195) and chondrosarcomas (n=172) of the base of skull have been treated with combined megavoltage photon and 160 MeV proton radiotherapy. All patients had previously undergone biopsy, subtotal or total tumor removal. 104 patients had two or more surgical procedures before radiotherapy. Following 3D treatment planning with delineation of target volumes and critical non-target structures, dose distributions and dose volume histograms were calculated [at the time of treatment delivery]. Radiotherapy was given once a day, 1.8 Gy or CGE (Cobalt Gy Equivalent: Proton Gy X 1.1) per fraction, 5 fractions per week, with prescribed target doses ranging from 63 CGE to 79.2 CGE (mean = 67.8 CGE). Doses to the brainstem surface were limited to ≤64 CGE and to the brainstem center to ≤53 CGE. Dose distributions were developed to limit dose to brainstem surface and center; current plans limit dose to surface and center to ≤64 CGE and ≤53 CGE, respectively. Brainstem toxicity was scored according to the RTOG grading system. Results: Follow-up ranged from 6 months to 21.4 years (mean = 42.5 months). Brainstem symptoms, attributable to the treatment, developed in 17 of 282 patients with local tumor control (6.0%), resulting in death of three patients. The mean time to onset of symptoms was 17 months (range: 4.5 to 177 months). These symptoms appeared in 89.5% within 3 years. Grading of the brainstem toxicity is listed in table 1. Actuarial rates of 5 and 10 year toxicity free survival were 87% and 82% respectively. Increased risk of brainstem toxicity was significantly associated with maximum brainstem dose

  3. Conformal Infinity

    OpenAIRE

    Frauendiener, J?rg

    2000-01-01

    The notion of conformal infinity has a long history within the research in Einstein's theory of gravity. Today, 'conformal infinity' is related to almost all other branches of research in general relativity, from quantisation procedures to abstract mathematical issues to numerical applications. This review article attempts to show how this concept gradually and inevitably evolved from physical issues, namely the need to understand gravitational radiation and isolated systems within the theory...

  4. Dosimetry study on the conventional and three dimensional conformal radiation treatment planning protocols for rectal cancer

    International Nuclear Information System (INIS)

    Cai Yong; He Yuxiang; Han Shukui; Wu Hao; Gong Jian; Xu Bo

    2007-01-01

    Objective: To compare the dose distribution of clinical target volume (CTV), in normal tissues and organs for patients with rectal cancer on the conventional radiotherapy (2D) and three dimension- al conformal radiation treatment (3DCRT). Methods: The CT image data of 36 rectal cancer patients treated with 3DCRT were studied. The CTV, small bowel, colon, bladder, pelvic bone marrow, and femoral head and neck were contoured on consecutive axial slices of CT images. Two 3DCRT and three conventional treatment planning protocols were simulated using three dimensional treatment planning system (CMS Focus 2.31), were defined as 3D-3, 3D-4, 2D-2, 2D-3, 2D-4. The difference of five treatment planning protocols on the CTV and normal structure by analysis of dose-volume histograms (DVHs) were compared. Results: The D 95 and V 95 of these five protocols all exceeded 97%. The conformity index(CI) of 3D was obviously larger than that of 2D protocol. The dose inhomogeneity(DI) in 4 DCRT was less than that of 3 DCRT. The 3D as compared with the 2D, significantly reduced the mean dose of 45 Gy to the small bowel and colon. The 3D-3 as compared with the 2D-3, the 3D-4 as compared with the 2D-4, the mean dose of small bowel and colon was reduced by 28.5% and 25.7%, respectively. The 3D-3 as compared with the 2D-2, the 3D-3 as compared with the 2D-3 and the 3D4 as compared with the 2D-4, the percentage volume of small bowel and colon which received 45 Gy was reduced by 80.8% , 51.1% and 54.7% , respectively. Either the mean dose, or the percentage volume receiving 35 Gy and 45 Gy to the pelvic bone and bladder, the 3D planning protocols had advanage over the 2D planning protocols. The V 45 of bladder in 2D-2 planning proto- col was the highest in all planning protocols, exceeding 98%, but the highest V 45 of bladder was only 50% in the other planning protocols. Conclusions: Even though the difference in pelvic CTV of rectal cancer patients between the conventional radiotherapy and 3

  5. Conformational analysis and circular dichroism of bilirubin, the yellow pigment of jaundice

    Science.gov (United States)

    Lightner, David A.; Person, Richard; Peterson, Blake; Puzicha, Gisbert; Pu, Yu-Ming; Bojadziev, Stefan

    1991-06-01

    Conformational analysis of (4Z, 15Z)-bilirubin-IX(alpha) by molecular mechanics computations reveals a global energy minimum folded conformation. Powerful added stabilization is achieved through intramolecular hydrogen bonding. Theoretical treatment of bilirubin as a molecular exciton predicts an intense bisignate circular dichroism spectrum for the folded conformation: (Delta) (epsilon) is congruent to 270 L (DOT) mole-1 (DOT) cm-1 for the $OM450 nm electronic transition(s). Synthesis of bilirubin analogs with propionic acid groups methylated at the (alpha) or (beta) position introduces an allosteric effect that allows for an optical resolution of the pigments, with enantiomers exhibiting the theoretically predicted circular dichroism.

  6. Conformal superalgebras via tractor calculus

    Science.gov (United States)

    Lischewski, Andree

    2015-01-01

    We use the manifestly conformally invariant description of a Lorentzian conformal structure in terms of a parabolic Cartan geometry in order to introduce a superalgebra structure on the space of twistor spinors and normal conformal vector fields formulated in purely algebraic terms on parallel sections in tractor bundles. Via a fixed metric in the conformal class, one reproduces a conformal superalgebra structure that has been considered in the literature before. The tractor approach, however, makes clear that the failure of this object to be a Lie superalgebra in certain cases is due to purely algebraic identities on the spinor module and to special properties of the conformal holonomy representation. Moreover, it naturally generalizes to higher signatures. This yields new formulas for constructing new twistor spinors and higher order normal conformal Killing forms out of existing ones, generalizing the well-known spinorial Lie derivative. Moreover, we derive restrictions on the possible dimension of the space of twistor spinors in any metric signature.

  7. Optimization of Gamma Knife treatment planning via guided evolutionary simulated annealing

    International Nuclear Information System (INIS)

    Zhang Pengpeng; Dean, David; Metzger, Andrew; Sibata, Claudio

    2001-01-01

    We present a method for generating optimized Gamma Knife trade mark sign (Elekta, Stockholm, Sweden) radiosurgery treatment plans. This semiautomatic method produces a highly conformal shot packing plan for the irradiation of an intracranial tumor. We simulate optimal treatment planning criteria with a probability function that is linked to every voxel in a volumetric (MR or CT) region of interest. This sigmoidal P + parameter models the requirement of conformality (i.e., tumor ablation and normal tissue sparing). After determination of initial radiosurgery treatment parameters, a guided evolutionary simulated annealing (GESA) algorithm is used to find the optimal size, position, and weight for each shot. The three-dimensional GESA algorithm searches the shot parameter space more thoroughly than is possible during manual shot packing and provides one plan that is suitable to the treatment criteria of the attending neurosurgeon and radiation oncologist. The result is a more conformal plan, which also reduces redundancy, and saves treatment administration time

  8. Conformational Effects of UV Light on DNA Origami.

    Science.gov (United States)

    Chen, Haorong; Li, Ruixin; Li, Shiming; Andréasson, Joakim; Choi, Jong Hyun

    2017-02-01

    The responses of DNA origami conformation to UV radiation of different wavelengths and doses are investigated. Short- and medium-wavelength UV light can cause photo-lesions in DNA origami. At moderate doses, the lesions do not cause any visible defects in the origami, nor do they significantly affect the hybridization capability. Instead, they help relieve the internal stress in the origami structure and restore it to the designed conformation. At high doses, staple dissociation increases which causes structural disintegration. Long-wavelength UV does not show any effect on origami conformation by itself. We show that this UV range can be used in conjunction with photoactive molecules for photo-reconfiguration, while avoiding any damage to the DNA structures.

  9. Visual Outcome and Tumor Control After Conformal Radiotherapy for Patients With Optic Nerve Sheath Meningioma

    International Nuclear Information System (INIS)

    Arvold, Nils D.; Lessell, Simmons; Bussiere, Marc; Beaudette, Kevin; Rizzo, Joseph F.; Loeffler, Jay S.; Shih, Helen A.

    2009-01-01

    Purpose: Optic nerve sheath meningioma (ONSM) is a rare tumor that almost uniformly leads to visual dysfunction and even blindness without intervention. Because surgical extirpation carries a high risk of postoperative blindness, vision-sparing treatment strategies are desirable. Methods and Materials: We retrospectively reviewed the outcomes of 25 patients (25 optic nerves) with ONSM, treated at a single institution with conformal fractionated radiotherapy by either stereotactic photon or proton radiation. Primary endpoints were local control and visual acuity. Results: The patients presented with symptoms of visual loss (21) or orbital pain (3) or were incidentally diagnosed by imaging (3). The mean age was 44 years, and 64% were female patients. The indication for treatment was the development or progression of symptoms. Of the patients, 13 were treated with photons, 9 were treated with protons, and 3 received a combination of photons and protons. The median dose delivered was 50.4 gray equivalents (range, 45-59.4 gray equivalents). Median follow-up after radiotherapy was 30 months (range, 3-168 months), with 3 patients lost to follow-up. At most recent follow-up, 21 of 22 patients (95%) had improved (14) or stable (7) visual acuity. One patient had worsened visual acuity after initial postirradiation improvement. Of the 22 patients, 20 (95%) had no radiographic progression. Three patients had evidence of asymptomatic, limited retinopathy on ophthalmologic examination, and one had recurrent ONSM 11 years after treatment. Conclusions: Highly conformal, fractionated radiation therapy for symptomatic primary ONSM provides tumor control and improvement in visual function in most cases, with minimal treatment-induced morbidity. Longer follow-up is needed to assess the durability of tumor control and treatment-related late effects.

  10. Conformal Fabrication of Colloidal Quantum Dot Solids for Optically Enhanced Photovoltaics

    KAUST Repository

    Labelle, André J.

    2015-05-26

    © 2015 American Chemical Society. Colloidal quantum dots (CQD) are an attractive thin-film material for photovoltaic applications due to low material costs, ease of fabrication, and size-tunable band gap. Unfortunately, today they suffer from a compromise between light absorption and photocarrier extraction, a fact that currently prevents the complete harvest of incoming above-band-gap solar photons. We have investigated the use of structured substrates and/or electrodes to increase the effective light path through the active material and found that these designs require highly conformal application of the light-absorbing films to achieve the greatest enhancement. This conformality requirement derives from the need for maximal absorption enhancement combined with shortest-distance charge transport. Here we report on a means of processing highly conformal layer-by-layer deposited CQD absorber films onto microstructured, light-recycling electrodes. Specifically, we engineer surface hydrophilicity to achieve conformal deposition of upper layers atop underlying ones. We show that only with the application of conformal coating can we achieve optimal quantum efficiency and enhanced power conversion efficiency in structured-electrode CQD cells.

  11. Fermion-scalar conformal blocks

    Energy Technology Data Exchange (ETDEWEB)

    Iliesiu, Luca [Joseph Henry Laboratories, Princeton University,Washington Road, Princeton, NJ 08544 (United States); Kos, Filip [Department of Physics, Yale University,217 Prospect Street, New Haven, CT 06520 (United States); Poland, David [Department of Physics, Yale University,217 Prospect Street, New Haven, CT 06520 (United States); School of Natural Sciences, Institute for Advanced Study,1 Einstein Dr, Princeton, New Jersey 08540 (United States); Pufu, Silviu S. [Joseph Henry Laboratories, Princeton University,Washington Road, Princeton, NJ 08544 (United States); Simmons-Duffin, David [School of Natural Sciences, Institute for Advanced Study,1 Einstein Dr, Princeton, New Jersey 08540 (United States); Yacoby, Ran [Joseph Henry Laboratories, Princeton University,Washington Road, Princeton, NJ 08544 (United States)

    2016-04-13

    We compute the conformal blocks associated with scalar-scalar-fermion-fermion 4-point functions in 3D CFTs. Together with the known scalar conformal blocks, our result completes the task of determining the so-called ‘seed blocks’ in three dimensions. Conformal blocks associated with 4-point functions of operators with arbitrary spins can now be determined from these seed blocks by using known differential operators.

  12. Evaluation of High Density Air Traffic Operations with Automation for Separation Assurance, Weather Avoidance and Schedule Conformance

    Science.gov (United States)

    Prevot, Thomas; Mercer, Joey S.; Martin, Lynne Hazel; Homola, Jeffrey R.; Cabrall, Christopher D.; Brasil, Connie L.

    2011-01-01

    In this paper we discuss the development and evaluation of our prototype technologies and procedures for far-term air traffic control operations with automation for separation assurance, weather avoidance and schedule conformance. Controller-in-the-loop simulations in the Airspace Operations Laboratory at the NASA Ames Research Center in 2010 have shown very promising results. We found the operations to provide high airspace throughput, excellent efficiency and schedule conformance. The simulation also highlighted areas for improvements: Short-term conflict situations sometimes resulted in separation violations, particularly for transitioning aircraft in complex traffic flows. The combination of heavy metering and growing weather resulted in an increased number of aircraft penetrating convective weather cells. To address these shortcomings technologies and procedures have been improved and the operations are being re-evaluated with the same scenarios. In this paper we will first describe the concept and technologies for automating separation assurance, weather avoidance, and schedule conformance. Second, the results from the 2010 simulation will be reviewed. We report human-systems integration aspects, safety and efficiency results as well as airspace throughput, workload, and operational acceptability. Next, improvements will be discussed that were made to address identified shortcomings. We conclude that, with further refinements, air traffic control operations with ground-based automated separation assurance can routinely provide currently unachievable levels of traffic throughput in the en route airspace.

  13. Fabrication challenges associated with conformal optics

    Science.gov (United States)

    Schaefer, John; Eichholtz, Richard A.; Sulzbach, Frank C.

    2001-09-01

    A conformal optic is typically an optical window that conforms smoothly to the external shape of a system platform to improve aerodynamics. Conformal optics can be on-axis, such as an ogive missile dome, or off-axis, such as in a free form airplane wing. A common example of conformal optics is the automotive head light window that conforms to the body of the car aerodynamics and aesthetics. The unusual shape of conformal optics creates tremendous challenges for design, manufacturing, and testing. This paper will discuss fabrication methods that have been successfully demonstrated to produce conformal missile domes and associated wavefront corrector elements. It will identify challenges foreseen with more complex free-form configurations. Work presented in this paper was directed by the Precision Conformal Optics Consortium (PCOT). PCOT is comprised of both industrial and academic members who teamed to develop and demonstrate conformal optical systems suitable for insertion into future military programs. The consortium was funded under DARPA agreement number MDA972-96-9-08000.

  14. Animation and radiobiological analysis of 3D motion in conformal radiotherapy.

    Science.gov (United States)

    MacKay, R I; Graham, P A; Moore, C J; Logue, J P; Sharrock, P J

    1999-07-01

    To allow treatment plans to be evaluated against the range of expected organ motion and set up error anticipated during treatment. Planning tools have been developed to allow concurrent animation and radiobiological analysis of three dimensional (3D) target and organ motion in conformal radiotherapy. Surfaces fitted to structures outlined on CT studies are projected onto pre-treatment images or onto megavoltage images collected during the patient treatment. Visual simulation of tumour and normal tissue movement is then performed by the application of three dimensional affine transformations, to the selected surface. Concurrent registration of the surface motion with the 3D dose distribution allows calculation of the change in dose to the volume. Realistic patterns of motion can be applied to the structure to simulate inter-fraction motion and set-up error. The biologically effective dose for the structure is calculated for each fraction as the surface moves over the course of the treatment and is used to calculate the normal tissue complication probability (NTCP) or tumour control probability (TCP) for the moving structure. The tool has been used to evaluate conformal therapy plans against set up measurements recorded during patient treatments. NTCP and TCP were calculated for a patient whose set up had been corrected after systematic deviations from plan geometry were measured during treatment, the effect of not making the correction were also assessed. TCP for the moving tumour was reduced if inadequate margins were set for the treatment. Modelling suggests that smaller margins could have been set for the set up corrected during the course of the treatment. The NTCP for the rectum was also higher for the uncorrected set up due to a more rectal tissue falling in the high dose region. This approach provides a simple way for clinical users to utilise information incrementally collected throughout the whole of a patient's treatment. In particular it is possible to

  15. Explicit mentalizing mechanisms and their adaptive role in memory conformity.

    Science.gov (United States)

    Wheeler, Rebecca; Allan, Kevin; Tsivilis, Dimitris; Martin, Douglas; Gabbert, Fiona

    2013-01-01

    Memory conformity occurs when an individual endorses what other individuals remember about past events. Research on memory conformity is currently dominated by a 'forensic' perspective, which views the phenomenon as inherently undesirable. This is because conformity not only distorts the accuracy of an individual's memory, but also produces false corroboration between individuals, effects that act to undermine criminal justice systems. There is growing awareness, however, that memory conformity may be interpreted more generally as an adaptive social behavior regulated by explicit mentalizing mechanisms. Here, we provide novel evidence in support of this emerging alternative theoretical perspective. We carried out a memory conformity experiment which revealed that explicit belief-simulation (i.e. using one's own beliefs to model what other people believe) systematically biases conformity towards like-minded individuals, even when there is no objective evidence that they have a more accurate memory than dissimilar individuals. We suggest that this bias is functional, i.e. adaptive, to the extent that it fosters trust, and hence cooperation, between in-group versus out-group individuals. We conclude that memory conformity is, in more fundamental terms, a highly desirable product of explicit mentalizing mechanisms that promote adaptive forms of social learning and cooperation.

  16. Reactions driving conformational movements (molecular motors) in gels: conformational and structural chemical kinetics.

    Science.gov (United States)

    Otero, Toribio F

    2017-01-18

    In this perspective the empirical kinetics of conducting polymers exchanging anions and solvent during electrochemical reactions to get dense reactive gels is reviewed. The reaction drives conformational movements of the chains (molecular motors), exchange of ions and solvent with the electrolyte and structural (relaxation, swelling, shrinking and compaction) gel changes. Reaction-driven structural changes are identified and quantified from electrochemical responses. The empirical reaction activation energy (E a ), the reaction coefficient (k) and the reaction orders (α and β) change as a function of the conformational energy variation during the reaction. This conformational energy becomes an empirical magnitude. E a , k, α and β include and provide quantitative conformational and structural information. The chemical kinetics becomes structural chemical kinetics (SCK) for reactions driving conformational movements of the reactants. The electrochemically stimulated conformational relaxation model describes empirical results and some results from the literature for biochemical reactions. In parallel the development of an emerging technological world of soft, wet, multifunctional and biomimetic tools and anthropomorphic robots driven by reactions of the constitutive material, as in biological organs, can be now envisaged being theoretically supported by the kinetic model.

  17. The value of 18F-FDG PET in three-dimensional conformal radiotherapy of cancer

    International Nuclear Information System (INIS)

    Lv Huiqing; Zhang Zhongmin; Lv Zhonghong

    2006-01-01

    Three-dimensional conformal radiotherapy (3D-CRT) is based on an extensive use of modern medical imaging techniques. Delineation of the gross tumor volume and organs at risk constitutes one of the most important phases of conformal radiotherapy procedures. 18 F-fluorodeoxyglucose ( 18 F-FDG) PET possesses greater sensitivity and accuracy in detecting diseased lymph nodes, is an important staging examination for patients considered for radiation treatment with curative intent. 18 F-FDG PET has an important role in delineation of gross tumor volume for patients treated with three-dimensional conformal radiotherapy. (authors)

  18. Core-shell silk hydrogels with spatially tuned conformations as drug-delivery system.

    Science.gov (United States)

    Yan, Le-Ping; Oliveira, Joaquim M; Oliveira, Ana L; Reis, Rui L

    2017-11-01

    Hydrogels of spatially controlled physicochemical properties are appealing platforms for tissue engineering and drug delivery. In this study, core-shell silk fibroin (SF) hydrogels of spatially controlled conformation were developed. The core-shell structure in the hydrogels was formed by means of soaking the preformed (enzymatically crosslinked) random coil SF hydrogels in methanol. When increasing the methanol treatment time from 1 to 10 min, the thickness of the shell layer can be tuned from about 200 to about 850 μm as measured in wet status. After lyophilization of the rehydrated core-shell hydrogels, the shell layer displayed compact morphology and the core layer presented porous structure, when observed by scanning electron microscopy. The conformation of the hydrogels was evaluated by Fourier transform infrared spectroscopy in wet status. The results revealed that the shell layer possessed dominant β-sheet conformation and the core layer maintained mainly random coil conformation. Enzymatic degradation data showed that the shell layers presented superior stability to the core layer. The mechanical analysis displayed that the compressive modulus of the core-shell hydrogels ranged from about 25 kPa to about 1.1 MPa by increasing the immersion time in methanol. When incorporated with albumin, the core-shell SF hydrogels demonstrated slower and more controllable release profiles compared with the non-treated hydrogel. These core-shell SF hydrogels of highly tuned properties are useful systems as drug-delivery system and may be applied as cartilage substitute. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Axiomatic conformal field theory

    International Nuclear Information System (INIS)

    Gaberdiel, M.R.; Goddard, P.

    2000-01-01

    A new rigourous approach to conformal field theory is presented. The basic objects are families of complex-valued amplitudes, which define a meromorphic conformal field theory (or chiral algebra) and which lead naturally to the definition of topological vector spaces, between which vertex operators act as continuous operators. In fact, in order to develop the theory, Moebius invariance rather than full conformal invariance is required but it is shown that every Moebius theory can be extended to a conformal theory by the construction of a Virasoro field. In this approach, a representation of a conformal field theory is naturally defined in terms of a family of amplitudes with appropriate analytic properties. It is shown that these amplitudes can also be derived from a suitable collection of states in the meromorphic theory. Zhu's algebra then appears naturally as the algebra of conditions which states defining highest weight representations must satisfy. The relationship of the representations of Zhu's algebra to the classification of highest weight representations is explained. (orig.)

  20. Neural mechanisms underlying social conformity in an ultimatum game

    Directory of Open Access Journals (Sweden)

    Zhenyu eWei

    2013-12-01

    Full Text Available When individuals’ actions are incongruent with those of the group they belong to, they may change their initial behavior in order to conform to the group norm. This phenomenon is known as social conformity. In the present study, we used event-related functional magnetic resonance imaging (fMRI to investigate brain activity in response to group opinion during an ultimatum game. Results showed that participants changed their choices when these choices conflicted with the normative opinion of the group they were members of, especially in conditions of unfair treatment. The fMRI data revealed that a conflict with group norms activated the brain regions involved in norm violations and behavioral adjustment. Furthermore, in the reject-unfair condition, we observed that a conflict with group norms activated the medial frontal gyrus. These findings contribute to recent research examining neural mechanisms involved in detecting violations of social norms, and provide information regarding the neural representation of conformity behavior in an economic game.

  1. Conformal description of spinning particles

    International Nuclear Information System (INIS)

    Todorov, I.T.

    1986-01-01

    This book is an introduction to the application of the conformal group to quantum field theory of particles with spin. After an introduction to the twistor representations of the conformal group of a conformally flat space-time and twistor flag manifolds with Su(2,2) orbits the classical phase space of conformal spinning particles is described. Thereafter the twistor description of classical zero mass fields is considered together with the quantization. (HSI)

  2. Conformal boundaries of warped products

    DEFF Research Database (Denmark)

    Kokkendorff, Simon Lyngby

    2006-01-01

    In this note we prove a result on how to determine the conformal boundary of a type of warped product of two length spaces in terms of the individual conformal boundaries. In the situation, that we treat, the warping and conformal distortion functions are functions of distance to a base point....... The result is applied to produce examples of CAT(0)-spaces, where the conformal and ideal boundaries differ in interesting ways....

  3. Conformally connected universes

    International Nuclear Information System (INIS)

    Cantor, M.; Piran, T.

    1983-01-01

    A well-known difficulty associated with the conformal method for the solution of the general relativistic Hamiltonian constraint is the appearance of an aphysical ''bag of gold'' singularity at the nodal surface of the conformal factor. This happens whenever the background Ricci scalar is too large. Using a simple model, it is demonstrated that some of these singular solutions do have a physical meaning, and that these can be considered as initial data for Universe containing black holes, which are connected, in a conformally nonsingular way with each other. The relation between the ADM mass and the horizon area in this solution supports the cosmic censorship conjecture. (author)

  4. Geometric accuracy of field alignment in fractionated stereotactic conformal radiotherapy of brain tumors

    International Nuclear Information System (INIS)

    Kortmann, Rolf D.; Becker, Gerd; Perelmouter, Jury; Buchgeister, Markus; Meisner, Christoph; Bamberg, Michael

    1999-01-01

    Purpose: To assess the accuracy of field alignment in patients undergoing three-dimensional (3D) conformal radiotherapy of brain tumors, and to evaluate the impact on the definition of planning target volume and control procedures. Methods and Materials: Geometric accuracy was analyzed in 20 patients undergoing fractionated stereotactic conformal radiotherapy for brain tumors. Rigid head fixation was achieved by using cast material. Transfer of stereotactic coordinates was performed by an external positioning device. The accuracy during treatment planning was quantitatively assessed by using repeated computed tomography (CT) examinations in treatment position (reproducibility of isocenter). Linear discrepancies were measured between treatment plan and CT examination. In addition, for each patient, a series of 20 verifications were taken in orthogonal projections. Linear discrepancies were measured between first and all subsequent verifications (accuracy during treatment delivery). Results: For the total group of patients, the distribution of deviations during treatment setup showed mean values between -0.3-1.2 mm, with standard deviations (SD) of 1.3-2.0 mm. During treatment delivery, the distribution of deviations revealed mean values between 0.7-0.8 mm, with SDs of 0.5-0.6 mm, respectively. For all patients, deviations for the transition to the treatment machine were similar to deviations during subsequent treatment delivery, with 95% of all absolute deviations between less than 2.8 and 4.6 mm. Conclusion: Random fluctuations of field displacements during treatment planning and delivery prevail. Therefore, our quantitative data should be considered when prescribing the safety margins of the planning target volume. Repeated CT examination are useful to detect operator errors and large random or systematic deviations before start of treatment. Control procedures during treatment delivery appear to be of limited importance. In addition, our findings should help to

  5. Smart Conformists: Children and Adolescents Associate Conformity With Intelligence Across Cultures.

    Science.gov (United States)

    Wen, Nicole J; Clegg, Jennifer M; Legare, Cristine H

    2017-08-24

    The current study used a novel methodology based on multivocal ethnography to assess the relations between conformity and evaluations of intelligence and good behavior among Western (U.S.) and non-Western (Ni-Vanuatu) children (6- to 11-year-olds) and adolescents (13- to 17-year-olds; N = 256). Previous research has shown that U.S. adults were less likely to endorse high-conformity children as intelligent than Ni-Vanuatu adults. The current data demonstrate that in contrast to prior studies documenting cultural differences between adults' evaluations of conformity, children and adolescents in the United States and Vanuatu have a conformity bias when evaluating peers' intelligence and behavior. Conformity bias for good behavior increases with age. The results have implications for understanding the interplay of conformity bias and trait psychology across cultures and development. © 2017 The Authors. Child Development © 2017 Society for Research in Child Development, Inc.

  6. On Associative Conformal Algebras of Linear Growth

    OpenAIRE

    Retakh, Alexander

    2000-01-01

    Lie conformal algebras appear in the theory of vertex algebras. Their relation is similar to that of Lie algebras and their universal enveloping algebras. Associative conformal algebras play a role in conformal representation theory. We introduce the notions of conformal identity and unital associative conformal algebras and classify finitely generated simple unital associative conformal algebras of linear growth. These are precisely the complete algebras of conformal endomorphisms of finite ...

  7. Bladder filling variation during conformal radiotherapy for rectal cancer

    Science.gov (United States)

    Sithamparam, S.; Ahmad, R.; Sabarudin, A.; Othman, Z.; Ismail, M.

    2017-05-01

    Conformal radiotherapy for rectal cancer is associated with small bowel toxicity mainly diarrhea. Treating patients with a full bladder is one of the practical solutions to reduce small bowel toxicity. Previous studies on prostate and cervix cancer patients revealed that maintaining consistent bladder volume throughout radiotherapy treatment is challenging. The aim of this study was to measure bladder volume variation throughout radiotherapy treatment. This study also measured the association between bladder volume changes and diarrhea. Twenty two rectal cancer patients were recruited prospectively. Patients were planned for treatment with full bladder following departmental bladder filling protocol and the planning bladder volume was measured during CT-simulation. During radiotherapy, the bladder volume was measured weekly using cone-beam computed tomography (CBCT) and compared to planning bladder volume. Incidence and severity of diarrhea were recorded during the weekly patient review. There was a negative time trend for bladder volume throughout five weeks treatment. The mean bladder volume decreased 18 % from 123 mL (SD 54 mL) during CT-simulation to 101 mL (SD 71 mL) on the 5th week of radiotherapy, but the decrease is not statistically significant. However, there was a large variation of bladder volume within each patient during treatment. This study showed an association between changes of bladder volume and diarrhea (P = 0.045). In conclusion bladder volume reduced throughout radiotherapy treatment for conformal radiotherapy for rectal cancer and there was a large variation of bladder volume within patients.

  8. Bladder filling variation during conformal radiotherapy for rectal cancer

    International Nuclear Information System (INIS)

    Sithamparam, S; Ahmad, R; Sabarudin, A; Othman, Z; Ismail, M

    2017-01-01

    Conformal radiotherapy for rectal cancer is associated with small bowel toxicity mainly diarrhea. Treating patients with a full bladder is one of the practical solutions to reduce small bowel toxicity. Previous studies on prostate and cervix cancer patients revealed that maintaining consistent bladder volume throughout radiotherapy treatment is challenging. The aim of this study was to measure bladder volume variation throughout radiotherapy treatment. This study also measured the association between bladder volume changes and diarrhea. Twenty two rectal cancer patients were recruited prospectively. Patients were planned for treatment with full bladder following departmental bladder filling protocol and the planning bladder volume was measured during CT-simulation. During radiotherapy, the bladder volume was measured weekly using cone-beam computed tomography (CBCT) and compared to planning bladder volume. Incidence and severity of diarrhea were recorded during the weekly patient review. There was a negative time trend for bladder volume throughout five weeks treatment. The mean bladder volume decreased 18 % from 123 mL (SD 54 mL) during CT-simulation to 101 mL (SD 71 mL) on the 5th week of radiotherapy, but the decrease is not statistically significant. However, there was a large variation of bladder volume within each patient during treatment. This study showed an association between changes of bladder volume and diarrhea (P = 0.045). In conclusion bladder volume reduced throughout radiotherapy treatment for conformal radiotherapy for rectal cancer and there was a large variation of bladder volume within patients. (paper)

  9. Evaluation of Geometrically Optimized Single- and Double-plane Interstitial High Dose Rate Implants with Respect to Conformality and Homogeneity

    International Nuclear Information System (INIS)

    Major, Tibor; Polgar, Csaba; Fodor, Janos; Takacsi-nagy, Zoltan; Mangel, Laszlo; Nemeth, Gyoergy

    2003-01-01

    The use of a stepping source in high dose rate brachytherapy supported with dwell-time optimization makes it possible to deviate from the classical dosimetry systems. Dose distributions of single- and double-plane implants were analysed for conformality and homogeneity at idealized target volumes. The Paris system was used for catheter positioning and target volume determination. Geometric optimization and individual dose prescription were applied. Volumetric indices and dose parameters were calculated at optimal active length, which was found to be equal to target volume length. The mean conformality, homogeneity, external volume and overdose volume indices were 0.78, 0.67, 0.22 and 0.13, respectively. The average minimum target and reference doses were 69% and 86%, respectively. Comparisons between the volumetric indices of geometrical optimized and non-optimized implants were also performed, and a significant difference was found regarding any index. The geometrical optimization resulted in superior conformality and slightly inferior homogeneity. At geometrically optimized implants, the active length can be reduced compared to non-optimized implants. Volumetric parameters and dose-volume histogram-based individual dose prescription are recommended for quantitative assessment of interstitial implants

  10. Recurrent craniopharyngioma after conformal radiation in children and the burden of treatment.

    Science.gov (United States)

    Klimo, Paul; Venable, Garrett T; Boop, Frederick A; Merchant, Thomas E

    2015-05-01

    In this paper the authors present their experience treating children with recurrent craniopharyngioma who were initially managed with surgery followed by conformal radiation therapy (CRT). A departmental oncology information system was queried to identify all children (craniopharyngioma between 1998 and 2010 (inclusive) and specifically those who experienced tumor progression. For each patient, the authors recorded the type of recurrence (solid, cystic, or both), the time interval to first progression and each subsequent progression, the associated treatment complications, and disease status at last follow-up evaluation. Among the 97 patients that met criteria for entry into this study, 18 (18.6%) experienced tumor progression (9 cystic, 3 solid, 6 cystic and solid). The median time to first recurrence was 4.62 years (range 1.81-9.11 years). The subgroup included 6 female and 12 male patients with a median age of 7.54 years (range 3.61-13.83 years). Ten patients experienced first progression within 5 years of CRT. The 5- and 10-year treatment-free survival rates for the entire cohort were 89.0% (95% confidence interval [CI] 80.5%-93.9%) and 76.2% (95% CI 64%-85%), respectively. Seven patients had a single episode of progression and 11 had more than 1. The time interval between each subsequent progression was progressively shorter. The 18 patients underwent 38 procedures. The median follow-up duration for this group was 9.32 years (range 4.04-19.0 years). Three patients died, including 1 from perioperative complications. Craniopharyngioma progression after prior irradiation is exceedingly difficult to treat and local control is challenging despite repeated surgical procedures. Given our results, gross-total resection may need to be the surgical goal at the time of first recurrence, if possible. Decompressing new cyst formation alone has a low rate of long-term success.

  11. Conformal algebra of Riemann surfaces

    International Nuclear Information System (INIS)

    Vafa, C.

    1988-01-01

    It has become clear over the last few years that 2-dimensional conformal field theories are a crucial ingredient of string theory. Conformal field theories correspond to vacuum solutions of strings; or more precisely we know how to compute string spectrum and scattering amplitudes by starting from a formal theory (with a proper value of central charge of the Virasoro algebra). Certain non-linear sigma models do give rise to conformal theories. A lot of progress has been made in the understanding of conformal theories. The author discusses a different view of conformal theories which was motivated by the development of operator formalism on Riemann surfaces. The author discusses an interesting recent work from this point of view

  12. Conformality lost

    International Nuclear Information System (INIS)

    Kaplan, David B.; Lee, Jong-Wan; Son, Dam T.; Stephanov, Mikhail A.

    2009-01-01

    We consider zero-temperature transitions from conformal to nonconformal phases in quantum theories. We argue that there are three generic mechanisms for the loss of conformality in any number of dimensions: (i) fixed point goes to zero coupling, (ii) fixed point runs off to infinite coupling, or (iii) an IR fixed point annihilates with a UV fixed point and they both disappear into the complex plane. We give both relativistic and nonrelativistic examples of the last case in various dimensions and show that the critical behavior of the mass gap behaves similarly to the correlation length in the finite temperature Berezinskii-Kosterlitz-Thouless (BKT) phase transition in two dimensions, ξ∼exp(c/|T-T c | 1/2 ). We speculate that the chiral phase transition in QCD at large number of fermion flavors belongs to this universality class, and attempt to identify the UV fixed point that annihilates with the Banks-Zaks fixed point at the lower end of the conformal window.

  13. Selection and determination of beam weights based on genetic algorithms for conformal radiotherapy treatment planning

    International Nuclear Information System (INIS)

    Xingen Wu; Zunliang Wang

    2000-01-01

    A genetic algorithm has been used to optimize the selection of beam weights for external beam three-dimensional conformal radiotherapy treatment planning. A fitness function is defined, which includes a difference function to achieve a least-square fit to doses at preselected points in a planning target volume, and a penalty item to constrain the maximum allowable doses delivered to critical organs. Adjustment between the dose uniformity within the target volume and the dose constraint to the critical structures can be achieved by varying the beam weight variables in the fitness function. A floating-point encoding schema and several operators, like uniform crossover, arithmetical crossover, geometrical crossover, Gaussian mutation and uniform mutation, have been used to evolve the population. Three different cases were used to verify the correctness of the algorithm and quality assessment based on dose-volume histograms and three-dimensional dose distributions were given. The results indicate that the genetic algorithm presented here has considerable potential. (author)

  14. 3D Conformal radiotherapy for gastric cancer-results of a comparative planning study

    International Nuclear Information System (INIS)

    Leong, Trevor; Willis, David; Joon, Daryl Lim; Condron, Sara; Hui, Andrew; Ngan, Samuel Y.K.

    2005-01-01

    Background and purpose: Many radiation oncologists are reluctant to use anteroposterior-posteroanterior (AP-PA) field arrangements when treating gastric cancer with adjuvant postoperative radiotherapy due to concerns about normal tissue toxicity, particularly in relation to the kidneys and spinal cord. In this report, we describe a multiple-field conformal radiotherapy technique, and compare this technique to the more commonly used AP-PA technique that was used in the recently reported Intergroup study (INT0116). Materials and methods: Fifteen patients with stages II-IV adenocarcinoma of the stomach were treated with adjuvant postoperative chemoradiotherapy using a standardised 3D conformal radiotherapy technique that consisted of a 'split-field', mono-isocentric arrangement employing 6 radiation fields. For each patient, a second radiotherapy treatment plan was generated utilising AP-PA fields. The two techniques were then compared for target volume coverage and dose to normal tissues using dose volume histogram (DVH) analysis. Results: The conformal technique provides more adequate coverage of the target volume with 99% of the planning target volume (PTV) receiving 95% of the prescribed dose, compared to 93% using AP-PA fields. Comparative DVHs for the right kidney, left kidney and spinal cord demonstrate lower radiation doses using the conformal technique, and although the liver dose is higher, it is still well below liver tolerance. Conclusions: 3D conformal radiotherapy produces superior dose distributions and reduced radiation doses to the kidneys and spinal cord compared to AP-PA techniques, with the potential to reduce treatment toxicity

  15. Gel dosimetry for conformal radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Gambarini, G [Department of Physics of the University and INFN, Milan (Italy)

    2005-07-01

    With the continuum development of conformal radio therapies, aimed at delivering high dose to tumor tissue and low dose to the healthy tissue around, the necessities has appeared of suitable improvement of dosimetry techniques giving the possibility of obtaining dose images to be compared with diagnostic images. Also if wide software has been developed for calculating dose distributions in the fields of various radiotherapy units, experimental verifications are necessary, in particular in the case of complex geometries in conformal radiotherapy. Gel dosimetry is a promising method for imaging the absorbed dose in tissue-equivalent phantoms, with the possibility of 3D reconstruction of the spatial dose distribution, with milli metric resolution. Optical imaging of gel dosimeters, based on visible light absorbance analysis, has shown to be a reliable technique for achieving dose distributions. (Author)

  16. Probing Protein Multidimensional Conformational Fluctuations by Single-Molecule Multiparameter Photon Stamping Spectroscopy

    Science.gov (United States)

    2015-01-01

    Conformational motions of proteins are highly dynamic and intrinsically complex. To capture the temporal and spatial complexity of conformational motions and further to understand their roles in protein functions, an attempt is made to probe multidimensional conformational dynamics of proteins besides the typical one-dimensional FRET coordinate or the projected conformational motions on the one-dimensional FRET coordinate. T4 lysozyme hinge-bending motions between two domains along α-helix have been probed by single-molecule FRET. Nevertheless, the domain motions of T4 lysozyme are rather complex involving multiple coupled nuclear coordinates and most likely contain motions besides hinge-bending. It is highly likely that the multiple dimensional protein conformational motions beyond the typical enzymatic hinged-bending motions have profound impact on overall enzymatic functions. In this report, we have developed a single-molecule multiparameter photon stamping spectroscopy integrating fluorescence anisotropy, FRET, and fluorescence lifetime. This spectroscopic approach enables simultaneous observations of both FRET-related site-to-site conformational dynamics and molecular rotational (or orientational) motions of individual Cy3-Cy5 labeled T4 lysozyme molecules. We have further observed wide-distributed rotational flexibility along orientation coordinates by recording fluorescence anisotropy and simultaneously identified multiple intermediate conformational states along FRET coordinate by monitoring time-dependent donor lifetime, presenting a whole picture of multidimensional conformational dynamics in the process of T4 lysozyme open-close hinge-bending enzymatic turnover motions under enzymatic reaction conditions. By analyzing the autocorrelation functions of both lifetime and anisotropy trajectories, we have also observed the dynamic and static inhomogeneity of T4 lysozyme multidimensional conformational fluctuation dynamics, providing a fundamental

  17. Results of three-dimensional conformal radiotherapy and thalidomide for advanced hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Hsu, Wei-Chung; Chung, Na-Na; Wang, Po-Ming; Ying, Kung-Shih; Shin, Jeng-Shiann; Chao, Che-Jen; Lin, Gau-De; Chan, Sue-Ching; Ting, Lai-Lei

    2006-01-01

    The purpose of this study was to evaluate the effectiveness of three-dimensional conformal radiotherapy and thalidomide in the treatment of advanced hepatocellular carcinoma. Between 1999 and 2003, 121 patients (mean age, 54.4±12.4 years; range, 20-81 years) with advanced hepatocellular carcinoma received three-dimensional conformal radiotherapy and thalidomide. Radiation was delivered in 1.5 Gy fractions twice daily for 5 days a week, for a total dose of 45-75 Gy. Mean treatment volume was 429.52±408.50 cm 3 (range, 26.89-2284.82 cm 3 ). Thalidomide was given concomitantly: 200 mg/day in 109 patients, 300 mg/day in 8 patients and 400 mg/day in 4 patients. Treatment responses, survival rates and factors affecting survival were analyzed. Treatment responses were observed in 61% of the patients. Liver cirrhosis (P=0.001) and tumor size (P=0.001) significantly affected the tumor responses. Overall survival at 6, 12 and 24 months was 84.8, 60.0 and 44.6%, respectively. On univariate analysis, liver cirrhosis (P=0.003), Karnofsky performance status (P=0.007), tumor size (P<0.001), portal vein tumor thrombosis (P<0.001) and alpha-fetoprotein level (P=0.003) were shown to significantly affect survival. On multivariate analysis, only thrombosis (P=0.039) and alpha-fetoprotein level (P=0.006) were shown to be factors affecting survival. Three-dimensional conformal radiotherapy with thalidomide seems to be effective in the treatment of advanced hepatocellular carcinoma. (author)

  18. 40 CFR 93.154 - Conformity analysis.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Conformity analysis. 93.154 Section 93...) DETERMINING CONFORMITY OF FEDERAL ACTIONS TO STATE OR FEDERAL IMPLEMENTATION PLANS Determining Conformity of General Federal Actions to State or Federal Implementation Plans § 93.154 Conformity analysis. Any Federal...

  19. Explicit mentalizing mechanisms and their adaptive role in memory conformity.

    Directory of Open Access Journals (Sweden)

    Rebecca Wheeler

    Full Text Available Memory conformity occurs when an individual endorses what other individuals remember about past events. Research on memory conformity is currently dominated by a 'forensic' perspective, which views the phenomenon as inherently undesirable. This is because conformity not only distorts the accuracy of an individual's memory, but also produces false corroboration between individuals, effects that act to undermine criminal justice systems. There is growing awareness, however, that memory conformity may be interpreted more generally as an adaptive social behavior regulated by explicit mentalizing mechanisms. Here, we provide novel evidence in support of this emerging alternative theoretical perspective. We carried out a memory conformity experiment which revealed that explicit belief-simulation (i.e. using one's own beliefs to model what other people believe systematically biases conformity towards like-minded individuals, even when there is no objective evidence that they have a more accurate memory than dissimilar individuals. We suggest that this bias is functional, i.e. adaptive, to the extent that it fosters trust, and hence cooperation, between in-group versus out-group individuals. We conclude that memory conformity is, in more fundamental terms, a highly desirable product of explicit mentalizing mechanisms that promote adaptive forms of social learning and cooperation.

  20. Recursion Relations for Conformal Blocks

    CERN Document Server

    Penedones, João; Yamazaki, Masahito

    2016-09-12

    In the context of conformal field theories in general space-time dimension, we find all the possible singularities of the conformal blocks as functions of the scaling dimension $\\Delta$ of the exchanged operator. In particular, we argue, using representation theory of parabolic Verma modules, that in odd spacetime dimension the singularities are only simple poles. We discuss how to use this information to write recursion relations that determine the conformal blocks. We first recover the recursion relation introduced in 1307.6856 for conformal blocks of external scalar operators. We then generalize this recursion relation for the conformal blocks associated to the four point function of three scalar and one vector operator. Finally we specialize to the case in which the vector operator is a conserved current.

  1. The logarithmic conformal field theories

    International Nuclear Information System (INIS)

    Rahimi Tabar, M.R.; Aghamohammadi, A.; Khorrami, M.

    1997-01-01

    We study the correlation functions of logarithmic conformal field theories. First, assuming conformal invariance, we explicitly calculate two- and three-point functions. This calculation is done for the general case of more than one logarithmic field in a block, and more than one set of logarithmic fields. Then we show that one can regard the logarithmic field as a formal derivative of the ordinary field with respect to its conformal weight. This enables one to calculate any n-point function containing the logarithmic field in terms of ordinary n-point functions. Finally, we calculate the operator product expansion (OPE) coefficients of a logarithmic conformal field theory, and show that these can be obtained from the corresponding coefficients of ordinary conformal theory by a simple derivation. (orig.)

  2. Deep Inelastic Scattering in Conformal QCD

    CERN Document Server

    Cornalba, Lorenzo; Penedones, Joao

    2010-01-01

    We consider the Regge limit of a CFT correlation function of two vector and two scalar operators, as appropriate to study small-x deep inelastic scattering in N=4 SYM or in QCD assuming approximate conformal symmetry. After clarifying the nature of the Regge limit for a CFT correlator, we use its conformal partial wave expansion to obtain an impact parameter representation encoding the exchange of a spin j Reggeon for any value of the coupling constant. The CFT impact parameter space is the three-dimensional hyperbolic space H3, which is the impact parameter space for high energy scattering in the dual AdS space. We determine the small-x structure functions associated to the exchange of a Reggeon. We discuss unitarization from the point of view of scattering in AdS and comment on the validity of the eikonal approximation. We then focus on the weak coupling limit of the theory where the amplitude is dominated by the exchange of the BFKL pomeron. Conformal invariance fixes the form of the vector impact factor a...

  3. Recent advancements in conformal gravity

    International Nuclear Information System (INIS)

    O’Brien, James G.; Chaykov, Spasen S.; Moss, Robert J.; Dentico, Jeremy; Stulge, Modestas; Stefanski, Brian

    2017-01-01

    In recent years, due to the lack of direct observed evidence of cold dark matter, coupled with the shrinking parameter space to search for new dark matter particles, there has been increased interest in Alternative Gravitational theories. This paper, addresses three recent advances in conformal gravity, a fourth order renormalizable metric theory of gravitation originally formulated by Weyl, and later advanced by Mannheim and Kazanas. The first section of the paper applies conformal gravity to the rotation curves of the LITTLE THINGS survey, extending the total number of rotation curves successfully fit by conformal gravity to well over 200 individual data sets without the need for additional dark matter. Further, in this rotation curve study, we show how MOND and conformal gravity compare for each galaxy in the sample. Second, we look at the original Zwicky problem of applying the virial theorem to the Coma cluster in order to get an estimate for the cluster mass. However, instead of using the standard Newtonian potential, here we use the weak field approximation of conformal gravity. We show that in the conformal case we can get a much smaller mass estimate and thus there is no apparent need to include dark matter. We then show that this calculation is in agreement with the observational data from other well studied clusters. Last, we explore the calculation of the deflection of starlight through conformal gravity, as a first step towards applying conformal gravity to gravitaitonal lensing. (paper)

  4. Three dimensional conformal radiation therapy may improve the therapeutic ratio of radiation therapy after pneumonectomy for lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Trouette, R; Causse, N; Elkhadri, M; Caudry, M; Maire, J P; Houlard, J P; Racaldini, L; Demeaux, H

    1995-12-01

    Three dimensional conformal radiation therapy would allow to decrease the normal tissue dose while maintaining the same target dose as standard treatment. To evaluate the feasibility of normal tissue dose reduction for ten patients with pneumonectomy for lung cancer, we determined the dose distribution to the normal tissue with 3-dimensional conformal radiation therapy (3-DCRT) and conventional treatment planning (CTP). Dose-volume histograms for target and normal tissue (lung, heart) were used for comparison of the different treatment planning. The mean percentages of lung and heart volumes which received 40 Gy with 3-DCRT were respectively 63% and 37% of the mean percentage of lung and volumes which received the same dose with CTP. These preliminary results suggest that conformal therapy may improve the therapeutic ratio by reducing risk to normal tissue.

  5. Preschoolers' conformity (and its motivation) is linked to own and parents' personalities.

    Science.gov (United States)

    Hellmer, Kahl; Stenberg, Gunilla; Fawcett, Christine

    2018-03-31

    Previous studies on conformity have primarily focused on factors that moderate conformity rates overall and paid little attention to explaining the individual differences. In this study, we investigate five-factor model personality traits of both parents and children and experimentally elicited conformity in 3.5-year-olds (N = 59) using an Asch-like paradigm with which we measure both overt conformity (public responses) and covert opinions (private beliefs after conformist responses): A correct covert opinion after an incorrect conformist response results from a socially normative motivation, whereas an incorrect covert opinion results from an informational motivation. Our data show (1) low parental extroversion is associated with participants' overall rate of conformity, (2) and low participant extroversion and high openness are associated with an informational instead of a normative motivation to conform. This suggests that sensitivity to the social context or social engagement level, as manifested through extroversion, could be an important factor in conformist behaviour. Statement of contribution What is already known on this subject? We all conform, from early in life - and even when we should know better We can conform for normative and informational motivations Some are more prone to conform than others What does this study add? This is the first study to take an individual differences approach to developmental conformity Social engagement (extroversion) is an important factor in conformity. © 2018 The British Psychological Society.

  6. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT)

    Science.gov (United States)

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham

    2013-01-01

    Introduction Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147–53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue. Methods A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site. Results The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose–volume histogram (DVH) doses were consistently lower. Conclusion The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques. PMID:26229623

  7. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT)

    International Nuclear Information System (INIS)

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham

    2013-01-01

    Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147–53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue. A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site. The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose–volume histogram (DVH) doses were consistently lower. The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques

  8. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT).

    Science.gov (United States)

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham

    2013-12-01

    Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147-53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue. A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site. The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose-volume histogram (DVH) doses were consistently lower. The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques.

  9. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT)

    Energy Technology Data Exchange (ETDEWEB)

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham [Andrew Love Cancer Centre, Geelong Hospital, Geelong, Victoria (Australia)

    2013-12-15

    Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147–53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue. A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site. The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose–volume histogram (DVH) doses were consistently lower. The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques.

  10. Optimal hypofractionated conformal radiotherapy for large brain metastases in patients with high risk factors: a single-institutional prospective study

    International Nuclear Information System (INIS)

    Inoue, Hiroshi K; Sato, Hiro; Suzuki, Yoshiyuki; Saitoh, Jun-ichi; Noda, Shin-ei; Seto, Ken-ichi; Torikai, Kota; Sakurai, Hideyuki; Nakano, Takashi

    2014-01-01

    A single-institutional prospective study of optimal hypofractionated conformal radiotherapy for large brain metastases with high risk factors was performed based on the risk prediction of radiation-related complications. Eighty-eight patients with large brain metastases ≥10 cm 3 in critical areas treated from January 2010 to February 2014 using the CyberKnife were evaluated. The optimal dose and number of fractions were determined based on the surrounding brain volume circumscribed with a single dose equivalent (SDE) of 14 Gy (V14) to be less than 7 cm 3 for individual lesions. Univariate and multivariate analyses were conducted. As a result of optimal treatment, 92 tumors ranging from 10 to 74.6 cm 3 (median, 16.2 cm 3 ) in volume were treated with a median prescribed isodose of 57% and a median fraction number of five. In order to compare the results according to the tumor volume, the tumors were divided into the following three groups: 1) 10–19.9 cm 3 , 2) 20–29.9 cm 3 and 3) ≥30 cm 3 . The lesions were treated with a median prescribed isodose of 57%, 56% and 55%, respectively, and the median fraction number was five in all three groups. However, all tumors ≥20 cm 3 were treated with ≥ five fractions. The median SDE of the maximum dose in the three groups was 47.2 Gy, 48.5 Gy and 46.5 Gy, respectively. Local tumor control was obtained in 90.2% of the patients, and the median survival was nine months, with a median follow-up period of seven months (range, 3-41 months). There were no significant differences in the survival rates among the three groups. Six tumors exhibited marginal recurrence 7-36 months after treatment. Ten patients developed symptomatic brain edema or recurrence of pre-existing edema, seven of whom required osmo-steroid therapy. No patients developed radiation necrosis requiring surgical resection. Our findings demonstrate that the administration of optimal hypofractionated conformal radiotherapy based on the dose-volume prediction

  11. High-order Div- and Quasi Curl-Conforming Basis Functions for Calderón Multiplicative Preconditioning of the EFIE

    KAUST Repository

    Valdes, Felipe; Andriulli, Francesco P.; Cools, Kristof; Michielssen, Eric

    2011-01-01

    A new high-order Calderón multiplicative preconditioner (HO-CMP) for the electric field integral equation (EFIE) is presented. In contrast to previous CMPs, the proposed preconditioner allows for high-order surface representations and current expansions by using a novel set of high-order quasi curl-conforming basis functions. Like its predecessors, the HO-CMP can be seamlessly integrated into existing EFIE codes. Numerical results demonstrate that the linear systems of equations obtained using the proposed HO-CMP converge rapidly, regardless of the mesh density and of the order of the current expansion. © 2006 IEEE.

  12. High-order Div- and Quasi Curl-Conforming Basis Functions for Calderón Multiplicative Preconditioning of the EFIE

    KAUST Repository

    Valdes, Felipe

    2011-04-01

    A new high-order Calderón multiplicative preconditioner (HO-CMP) for the electric field integral equation (EFIE) is presented. In contrast to previous CMPs, the proposed preconditioner allows for high-order surface representations and current expansions by using a novel set of high-order quasi curl-conforming basis functions. Like its predecessors, the HO-CMP can be seamlessly integrated into existing EFIE codes. Numerical results demonstrate that the linear systems of equations obtained using the proposed HO-CMP converge rapidly, regardless of the mesh density and of the order of the current expansion. © 2006 IEEE.

  13. Probing the conformational dynamics of photosystem I in unconfined and confined spaces.

    Science.gov (United States)

    Das, Gaurav; Chattoraj, Shyamtanu; Nandi, Somen; Mondal, Prasenjit; Saha, Abhijit; Bhattacharyya, Kankan; Ghosh, Surajit

    2017-12-20

    The fluorescence dynamics of Photosystem I (PSI) in bulk water and inside a confined environment like a liposome have been investigated using time resolved confocal microscopy. In bulk water, PSI exhibits a major emission peak at ∼680 nm, while in the liposome it exhibits a markedly blue shifted emission maximum at ∼485 nm. This is indicative of conformational changes due to entrapment and emergence of a stressed conformation of PSI inside the liposome. The observed time constants for the fluorescence lifetime of PSI inside the liposome are significantly high as opposed to PSI in bulk water. More interestingly, the fluorescence intensity of PSI in bulk water exhibits strong fluctuations with many high intensity jumps and these are anti-correlated with the fluorescence lifetime of PSI. In contrast, inside the liposome, no such anti-correlated behaviour is observed. We further demonstrated that PSI exhibits at least two conformational states in bulk water, whereas a single conformation is observed inside the liposome, indicating the conformational rigidity and locking of the PSI complex inside a liposome.

  14. A study of the radiobiological modeling of the conformal radiation therapy in cancer treatment

    Science.gov (United States)

    Pyakuryal, Anil Prasad

    Cancer is one of the leading causes of mortalities in the world. The precise diagnosis of the disease helps the patients to select the appropriate modality of the treatments such as surgery, chemotherapy and radiation therapy. The physics of X-radiation and the advanced imaging technologies such as positron emission tomography (PET) and computed tomography (CT) plays an important role in the efficient diagnosis and therapeutic treatments in cancer. However, the accuracy of the measurements of the metabolic target volumes (MTVs) in the PET/CT dual-imaging modality is always limited. Similarly the external beam radiation therapy (XRT) such as 3D conformal radiotherapy (3DCRT) and intensity modulated radiation therapy (IMRT) is the most common modality in the radiotherapy treatment. These treatments are simulated and evaluated using the XRT plans and the standard methodologies in the commercial planning system. However, the normal organs are always susceptible to the radiation toxicity in these treatments due to lack of knowledge of the appropriate radiobiological models to estimate the clinical outcomes. We explored several methodologies to estimate MTVs by reviewing various techniques of the target volume delineation using the static phantoms in the PET scans. The review suggests that the more precise and practical method of delineating PET MTV should be an intermediate volume between the volume coverage for the standardized uptake value (SUV; 2.5) of glucose and the 50% (40%) threshold of the maximum SUV for the smaller (larger) volume delineations in the radiotherapy applications. Similarly various types of optimal XRT plans were designed using the CT and PET/CT scans for the treatment of various types of cancer patients. The qualities of these plans were assessed using the universal plan-indices. The dose-volume criteria were also examined in the targets and organs by analyzing the conventional dose-volume histograms (DVHs). The biological models such as tumor

  15. Conkiss: Conformal Kidneys Sparing 3D Noncoplanar Radiotherapy Treatment for Pancreatic Cancer As an Alternative to IMRT

    International Nuclear Information System (INIS)

    Sebestyen, Zsolt; Kovacs, Peter; Gulyban, Akos; Farkas, Robert; Bellyei, Szabolcs; Liposits, Gabor; Szigeti, Andras; Esik, Olga; Derczy, Katalin; Mangel, Laszlo

    2011-01-01

    When treating pancreatic cancer using standard (ST) 3D conformal radiotherapy (3D-CRT) beam arrangements, the kidneys often receive a higher dose than their probable tolerance limit. Our aim was to elaborate a new planning method that-similarly to IMRT-effectively spares the kidneys without compromising the target coverage. Conformal kidneys sparing (CONKISS) 5-field, noncoplanar plans were compared with ST plans for 23 consecutive patients retrospectively. Optimal beam arrangements were used consisting of a left- and right-wedged beam-pair and an anteroposterior beam inclined in the caudal direction. The wedge direction determination (WEDDE) algorithm was developed to adjust the adequate direction of wedges. The aimed organs at risk (OARs) mean dose limits were: kidney <12 Gy, liver <25 Gy, small bowels <30 Gy, and spinal cord maximum <45 Gy. Conformity and homogeneity indexes with z-test were used to evaluate and compare the different planning approaches. The mean dose to the kidneys decreased significantly (p < 0.05): left kidney 7.7 vs. 10.7 Gy, right kidney 9.1 vs. 11.7 Gy. Meanwhile the mean dose to the liver increased significantly (18.1 vs. 15.0 Gy). The changes in the conformity, homogeneity, and in the doses to other OARs were not significant. The CONKISS method balances the load among the OARs and significantly reduces the dose to the kidneys, without any significant change in the conformity and homogeneity. Using 3D-CRT the CONKISS method can be a smart alternative to IMRT to enhance the possibility of dose escalation.

  16. Conformal and Nearly Conformal Theories at Large N

    Science.gov (United States)

    Tarnoplskiy, Grigory M.

    In this thesis we present new results in conformal and nearly conformal field theories in various dimensions. In chapter two, we study different properties of the conformal Quantum Electrodynamics (QED) in continuous dimension d. At first we study conformal QED using large Nf methods, where Nf is the number of massless fermions. We compute its sphere free energy as a function of d, ignoring the terms of order 1/Nf and higher. For finite Nf we use the epsilon-expansion. Next we use a large Nf diagrammatic approach to calculate the leading corrections to CT, the coefficient of the two-point function of the stress-energy tensor, and CJ, the coefficient of the two-point function of the global symmetry current. We present explicit formulae as a function of d and check them versus the expectations in 2 and 4 - epsilon dimensions. In chapter three, we discuss vacuum stability in 1 + 1 dimensional conformal field theories with external background fields. We show that the vacuum decay rate is given by a non-local two-form. This two-form is a boundary term that must be added to the effective in/out Lagrangian. The two-form is expressed in terms of a Riemann-Hilbert decomposition for background gauge fields, and is given by its novel "functional'' version in the gravitational case. In chapter four, we explore Tensor models. Such models possess the large N limit dominated by the melon diagrams. The quantum mechanics of a real anti-commuting rank-3 tensor has a large N limit similar to the Sachdev-Ye-Kitaev (SYK) model. We also discuss the quantum mechanics of a complex 3-index anti-commuting tensor and argue that it is equivalent in the large N limit to a version of SYK model with complex fermions. Finally, we discuss models of a commuting tensor in dimension d. We study the spectrum of the large N quantum field theory of bosonic rank-3 tensors using the Schwinger-Dyson equations. We compare some of these results with the 4 - epsilon expansion, finding perfect agreement. We

  17. Conformational study of glyoxal bis(amidinohydrazone) by ab initio methods

    Science.gov (United States)

    Mannfors, B.; Koskinen, J. T.; Pietilä, L.-O.

    1997-08-01

    We report the first ab initio molecular orbital study on the ground state of the endiamine tautomer of glyoxal bis(amidinohydrazone) (or glyoxal bis(guanylhydrazone), GBG) free base. The calculations were performed at the following levels of theory: Hartree-Fock, second-order Møller-Plesset perturbation theory and density functional theory (B-LYP and B3-LYP) as implemented in the Gaussian 94 software. The standard basis set 6-31G(d) was found to be sufficient. The default fine grid of Gaussian 94 was used in the density functional calculations. Molecular properties, such as optimized structures, total energies and the electrostatic potential derived (CHELPG) atomic charges, were studied as functions of C-C and N-N conformations. The lowest energy conformation was found to be all- trans, in agreement with the experimental solid-state structure. The second conformer with respect to rotation around the central C-C bond was found to be the cis conformer with an MP2//HF energy of 4.67 kcal mol -1. For rotation around the N-N bond the energy increased monotonically from the trans conformation to the cis conformation, the cis energy being very high, 22.01 kcal mol -1 (MP2//HF). The atomic charges were shown to be conformation dependent, and the bond charge increments and especially the conformational changes of the bond charge increments were found to be easily transferable between structurally related systems.

  18. Dose escalation with 3D conformal treatment: five year outcomes, treatment optimization, and future directions

    International Nuclear Information System (INIS)

    Hanks, Gerald E.; Hanlon, Alexandra L. M.S.; Schultheiss, Timothy E.; Pinover, Wayne H.; Movsas, Benjamin; Epstein, Barry E.; Hunt, Margie

    1998-01-01

    Purpose: To report the 5-year outcomes of dose escalation with 3D conformal treatment (3DCRT) of prostate cancer. Methods and Materials: Two hundred thirty-two consecutive patients were treated with 3DCRT alone between 6/89 and 10/92 with ICRU reporting point dose that increased from 63 to 79 Gy. The median follow-up was 60 months, and any patient free of clinical or biochemical evidence of disease was termed bNED. Biochemical failure was defined as prostate-specific antigen (PSA) rising on two consecutive recordings and exceeding 1.5 ng/ml. Morbidity was reported by the Radiation Therapy Oncology Group (RTOG) scale, the Late Effects Normal Tissue (LENT) scale, and a Fox Chase modification of the latter (FC-LENT). All patients were treated with a four-field technique with a 1 cm clinical target volume (CTV) to planning target volume (PTV) margin to the prostate or prostate boost; the CTV and gross tumor volume (GTV) were the same. Actuarial rates of outcome were calculated by Kaplan-Meier and cumulative incidence methods and compared using the log rank and Gray's test statistic, respectively. Cox regression models were used to establish prognostic factors predictive of the various measures of outcome. Five-year Kaplan-Meier bNED rates were utilized by dose group to estimate logit response models for bNED and late morbidity. Results: PSA 10 ng/ml based on 5-year bNED results. No dose response was observed for patients with pretreatment PSA 10 ng/ml strongly suggests that clinical trials employing radiation should investigate the use of 3DCRT and prostate doses of 76-80 Gy

  19. Conformal and highly luminescent monolayers of Alq3 prepared by gas-phase molecular layer deposition.

    Science.gov (United States)

    Räupke, André; Albrecht, Fabian; Maibach, Julia; Behrendt, Andreas; Polywka, Andreas; Heiderhoff, Ralf; Helzel, Jonatan; Rabe, Torsten; Johannes, Hans-Hermann; Kowalsky, Wolfgang; Mankel, Eric; Mayer, Thomas; Görrn, Patrick; Riedl, Thomas

    2014-01-22

    The gas-phase molecular layer deposition (MLD) of conformal and highly luminescent monolayers of tris(8-hydroxyquinolinato)aluminum (Alq3) is reported. The controlled formation of Alq3 monolayers is achieved for the first time by functionalization of the substrate with amino groups, which serve as initial docking sites for trimethyl aluminum (TMA) molecules binding datively to the amine. Thereby, upon exposure to 8-hydroxyquinoline (8-HQ), the self-limiting formation of highly luminescent Alq3 monolayers is afforded. The growth process and monolayer formation were studied and verified by in situ quartz crystal monitoring, optical emission and absorption spectroscopy, and X-ray photoelectron spectroscopy. The nature of the MLD process provides an avenue to coat arbitrarily shaped 3D surfaces and porous structures with high surface areas, as demonstrated in this work for silica aerogels. The concept presented here paves the way to highly sensitive luminescent sensors and dye-sensitized metal oxides for future applications (e.g., in photocatalysis and solar cells).

  20. S-Adenosylmethionine conformations in solution and in protein complexes: Conformational influences of the sulfonium group

    DEFF Research Database (Denmark)

    Markham, George D.; Norrby, Per-Ola; Bock, Charles W.

    2002-01-01

    S-Adenosylmethionine (AdoMet) and other sulfonium ions play central roles in the metabolism of all organisms. The conformational preferences of AdoMet and two other biologically important sulfonium ions, S-methylmethionine and dimethylsulfonioproprionic acid, have been investigated by NMR...... and computational studies. Molecular mechanics parameters for the sulfonium center have been developed for the AMBER force field to permit analysis of NMR results and to enable comparison of the relative energies of the different conformations of AdoMet that have been found in crystal structures of complexes...... with proteins. S-Methylmethionine and S-dimethylsulfonioproprionate adopt a variety of conformations in aqueous solution; a conformation with an electrostatic interaction between the sulfonium sulfur and the carboxylate group is not noticeably favored, in contrast to the preferred conformation found by in vacuo...

  1. Conformal Killing vectors in Robertson-Walker spacetimes

    International Nuclear Information System (INIS)

    Maartens, R.; Maharaj, S.d.

    1986-01-01

    It is well known that Robertson-Walker spacetimes admit a conformal Killingl vector normal to the spacelike homogeneous hypersurfaces. Because these spacetimes are conformally flat, there are a further eight conformal Killing vectors, which are neither normal nor tangent to the homogeneous hypersurfaces. The authors find these further conformal Killing vectors and the Lie algebra of the full G 15 of conformal motions. Conditions on the metric scale factor are determined which reduce some of the conformal Killing vectors to homothetic Killing vectors or Killing vectors, allowing one to regain in a unified way the known special geometries. The non-normal conformal Killing vectors provide a counter-example to show that conformal motions do not, in general, map a fluid flow conformally. These non-normal vectors are also used to find the general solution of the null geodesic equation and photon Liouville equation. (author)

  2. In silico Exploration of the Conformational Universe of GPCRs.

    Science.gov (United States)

    Rodríguez-Espigares, Ismael; Kaczor, Agnieszka A; Selent, Jana

    2016-07-01

    The structural plasticity of G protein coupled receptors (GPCRs) leads to a conformational universe going from inactive to active receptor states with several intermediate states. Many of them have not been captured yet and their role for GPCR activation is not well understood. The study of this conformational space and the transition dynamics between different receptor populations is a major challenge in molecular biophysics. The rational design of effector molecules that target such receptor populations allows fine-tuning receptor signalling with higher specificity to produce drugs with safer therapeutic profiles. In this minireview, we outline highly conserved receptor regions which are considered determinant for the establishment of distinct receptor states. We then discuss in-silico approaches such as dimensionality reduction methods and Markov State Models to explore the GPCR conformational universe and exploit the obtained conformations through structure-based drug design. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. A surprising role for conformational entropy in protein function

    Science.gov (United States)

    Wand, A. Joshua; Moorman, Veronica R.; Harpole, Kyle W.

    2014-01-01

    Formation of high-affinity complexes is critical for the majority of enzymatic reactions involving proteins. The creation of the family of Michaelis and other intermediate complexes during catalysis clearly involves a complicated manifold of interactions that are diverse and complex. Indeed, computing the energetics of interactions between proteins and small molecule ligands using molecular structure alone remains a grand challenge. One of the most difficult contributions to the free energy of protein-ligand complexes to experimentally access is that due to changes in protein conformational entropy. Fortunately, recent advances in solution nuclear magnetic resonance (NMR) relaxation methods have enabled the use of measures-of-motion between conformational states of a protein as a proxy for conformational entropy. This review briefly summarizes the experimental approaches currently employed to characterize fast internal motion in proteins, how this information is used to gain insight into conformational entropy, what has been learned and what the future may hold for this emerging view of protein function. PMID:23478875

  4. The conformational dynamics of the mitochondrial Hsp70 chaperone.

    Science.gov (United States)

    Mapa, Koyeli; Sikor, Martin; Kudryavtsev, Volodymyr; Waegemann, Karin; Kalinin, Stanislav; Seidel, Claus A M; Neupert, Walter; Lamb, Don C; Mokranjac, Dejana

    2010-04-09

    Heat shock proteins 70 (Hsp70) represent a ubiquitous and conserved family of molecular chaperones involved in a plethora of cellular processes. The dynamics of their ATP hydrolysis-driven and cochaperone-regulated conformational cycle are poorly understood. We used fluorescence spectroscopy to analyze, in real time and at single-molecule resolution, the effects of nucleotides and cochaperones on the conformation of Ssc1, a mitochondrial member of the family. We report that the conformation of its ADP state is unexpectedly heterogeneous, in contrast to a uniform ATP state. Substrates are actively involved in determining the conformation of Ssc1. The J protein Mdj1 does not interact transiently with the chaperone, as generally believed, but rather is released slowly upon ATP hydrolysis. Analysis of the major bacterial Hsp70 revealed important differences between highly homologous members of the family, possibly explaining tuning of Hsp70 chaperones to meet specific functions in different organisms and cellular compartments. 2010 Elsevier Inc. All rights reserved.

  5. Conformal transformations in superspace

    International Nuclear Information System (INIS)

    Dao Vong Duc

    1977-01-01

    The spinor extension of the conformal algebra is investigated. The transformation law of superfields under the conformal coordinate inversion R defined in the superspace is derived. Using R-technique, the superconformally covariant two-point and three-point correlation functions are found

  6. Towards conformal loop quantum gravity

    International Nuclear Information System (INIS)

    Wang, Charles H-T

    2006-01-01

    A discussion is given of recent developments in canonical gravity that assimilates the conformal analysis of gravitational degrees of freedom. The work is motivated by the problem of time in quantum gravity and is carried out at the metric and the triad levels. At the metric level, it is shown that by extending the Arnowitt-Deser-Misner (ADM) phase space of general relativity (GR), a conformal form of geometrodynamics can be constructed. In addition to the Hamiltonian and Diffeomorphism constraints, an extra first class constraint is introduced to generate conformal transformations. This phase space consists of York's mean extrinsic curvature time, conformal three-metric and their momenta. At the triad level, the phase space of GR is further enlarged by incorporating spin-gauge as well as conformal symmetries. This leads to a canonical formulation of GR using a new set of real spin connection variables. The resulting gravitational constraints are first class, consisting of the Hamiltonian constraint and the canonical generators for spin-gauge and conformorphism transformations. The formulation has a remarkable feature of being parameter-free. Indeed, it is shown that a conformal parameter of the Barbero-Immirzi type can be absorbed by the conformal symmetry of the extended phase space. This gives rise to an alternative approach to loop quantum gravity that addresses both the conceptual problem of time and the technical problem of functional calculus in quantum gravity

  7. Dosimetric effect on pediatric conformal treatment plans using dynamic jaw with Tomotherapy HDA

    Energy Technology Data Exchange (ETDEWEB)

    Han, Eun Young, E-mail: eyhan@uams.edu [Department of Radiation Oncology, University of Arkansas Medical Sciences, Little Rock, AR (United States); Kim, Dong-Wook [Department of Radiation Oncology, Kyung Hee University Hospital, Seoul (Korea, Republic of); Zhang, Xin; Penagaricano, Jose; Liang, Xiaoying; Hardee, Matthew; Morrill, Steve; Ratanatharathorn, Vaneerat [Department of Radiation Oncology, University of Arkansas Medical Sciences, Little Rock, AR (United States)

    2015-10-01

    It is important to minimize the radiation dose delivered to healthy tissues in pediatric cancer treatment because of the risk of secondary malignancies. Tomotherapy HDA provides a dynamic jaw (DJ) delivery mode that creates a sharper penumbra at the craniocaudal ends of a target in addition to a fixed jaw (FJ) delivery mode. The purpose of this study was to evaluate its dosimetric effect on the pediatric cancer cases. We included 6 pediatric cases in this study. The dose profiles and plan statistics—target dose conformity, uniformity, organ-at-risk (OAR) mean dose, beam-on time, and integral dose—were compared for each case. Consequently, the target dose coverage and uniformity were similar for different jaw settings. The OAR dose sparing depended on its relative location to the target and disease sites. For example, in the head and neck cancer cases, the brain stem dose using DJ 2.5 was reduced by more than two-fold (2.4 Gy vs. 6.3 Gy) than that obtained with FJ 2.5. The integral dose with DJ 2.5 decreased by more than 9% compared with that with FJ 2.5. Thus, using dynamic jaw in pediatric cases could be critical to reduce a probability of a secondary malignancy.

  8. Tribological Behavior of Oil-Lubricated Laser Textured Steel Surfaces in Conformal Flat and Non-Conformal Contacts

    Energy Technology Data Exchange (ETDEWEB)

    Kovalchenko, A. M. [Inst. for Problems of Materials Science, Dept. 7, 3 Krzhizhanovsky Street, Kyiv 03142, UA (Corresponding author), e-mail: andrii.kovalchenko@gatech.edu; Erdemir, A. [Argonne National Lab., Energy Systems Division, 9700 South Cass Avenue, Argonne, IL 60439 US; Ajayi, O. O. [Argonne National Lab., Energy Systems Division, 9700 South Cass Avenue, Argonne, IL 60439 US; Etsion, I. [Technion-Israel Inst. of Technology, Dept. of Mechanical Engineering, Haifa 32000, IL

    2017-01-30

    Changing the surface texture of sliding surfaces is an effective way to manipulate friction and wear of lubricated surfaces. Having realized its potential, we have done very extensive studies on the effects of laser surface texturing (LST, which involves the creation of an array of microdimples on a surface) on friction and wear behavior of oil-lubricated steel surfaces in the early 2000s. In this paper, we reviewed some of our research accomplishments and assessed future directions of the laser texturing field in many diverse industrial applications. Our studies specifically addressed the impact of laser texturing on friction and wear of both the flat conformal and initial non-conformal point contact configurations using a pin-on-disk test rig under fully-flooded synthetic oil lubricants with different viscosities. Electrical resistance measurement between pin and LST disks was also used to determine the operating lubrication regimes in relation to friction. In conformal contact, we confirmed that LST could significantly expand the operating conditions for hydrodynamic lubrication to significantly much higher loads and slower speeds. In particular, with LST and higher viscosity oils, the low-friction full hydrodynamic regime was shifted to the far left in the Stribeck diagram. Overall, the beneficial effects of laser surface texturing were more pronounced at higher speeds and loads and with higher viscosity oil. LST was also observed to reduce the magnitude of friction coefficients in the boundary regime. For the non-conformal contact configuration, we determined that LST would produce more abrasive wear on the rubbing counterface compared to the untreated surfaces due to a reduction in lubricant fluid film thickness, as well as the highly uneven and rough nature of the textured surfaces. However, this higher initial wear rate has led to faster generation of a conformal contact, and thus transition from the high-friction boundary to lower friction mixed

  9. Treatment planning for conformation therapy using a multi-leaf collimator

    International Nuclear Information System (INIS)

    Boesecke, R.; Doll, J.; Bauer, B.; Schlegel, W.; Pastyr, O.; Lorenz, W.J.

    1988-01-01

    In high energy photon therapy an optimum dose distribution is achieved with an irradiation from several directions, thus adapting the field shape to the target volume. Some methods of irradiation planning using these techniques are presented. The result of such a treatment planning is demonstrated. (orig.) [de

  10. Highly Conformal Craniospinal Radiotherapy Techniques Can Underdose the Cranial Clinical Target Volume if Leptomeningeal Extension through Skull Base Exit Foramina is not Contoured.

    Science.gov (United States)

    Noble, D J; Ajithkumar, T; Lambert, J; Gleeson, I; Williams, M V; Jefferies, S J

    2017-07-01

    Craniospinal irradiation (CSI) remains a crucial treatment for patients with medulloblastoma. There is uncertainty about how to manage meningeal surfaces and cerebrospinal fluid (CSF) that follows cranial nerves exiting skull base foramina. The purpose of this study was to assess plan quality and dose coverage of posterior cranial fossa foramina with both photon and proton therapy. We analysed the radiotherapy plans of seven patients treated with CSI for medulloblastoma and primitive neuro-ectodermal tumours and three with ependymoma (total n = 10). Four had been treated with a field-based technique and six with TomoTherapy™. The internal acoustic meatus (IAM), jugular foramen (JF) and hypoglossal canal (HC) were contoured and added to the original treatment clinical target volume (Plan_CTV) to create a Test_CTV. This was grown to a test planning target volume (Test_PTV) for comparison with a Plan_PTV. Using Plan_CTV and Plan_PTV, proton plans were generated for all 10 cases. The following dosimetry data were recorded: conformity (dice similarity coefficient) and homogeneity index (D 2  - D 98 /D 50 ) as well as median and maximum dose (D 2% ) to Plan_PTV, V 95% and minimum dose (D 99.9% ) to Plan_CTV and Test_CTV and Plan_PTV and Test_PTV, V 95% and minimum dose (D 98% ) to foramina PTVs. Proton and TomoTherapy™ plans were more conformal (0.87, 0.86) and homogeneous (0.07, 0.04) than field-photon plans (0.79, 0.17). However, field-photon plans covered the IAM, JF and HC PTVs better than proton plans (P = 0.002, 0.004, 0.003, respectively). TomoTherapy™ plans covered the IAM and JF better than proton plans (P = 0.000, 0.002, respectively) but the result for the HC was not significant. Adding foramen CTVs/PTVs made no difference for field plans. The mean D min dropped 3.4% from Plan_PTV to Test_PTV for TomoTherapy™ (not significant) and 14.8% for protons (P = 0.001). Highly conformal CSI techniques may underdose meninges and CSF in the dural

  11. Mass generation within conformal invariant theories

    International Nuclear Information System (INIS)

    Flato, M.; Guenin, M.

    1981-01-01

    The massless Yang-Mills theory is strongly conformally invariant and renormalizable; however, when masses are introduced the theory becomes nonrenormalizable and weakly conformally invariant. Conditions which recover strong conformal invariance are discussed in the letter. (author)

  12. Conformal group actions and Segal's cosmology

    International Nuclear Information System (INIS)

    Werth, J.-E.

    1984-01-01

    A mathematical description of Segal's cosmological model in the framework of conformal group actions is presented. The relation between conformal and causal group actions on time-orientable Lorentzian manifolds is analysed and several examples are discussed. A criterion for the conformality of a map between Lorentzian manifolds is given. The results are applied to Segal's 'conformal compactification' of Minkowski space. Furthermore, the 'unitary formulation' of Segal's cosmology is regarded. (Author) [pt

  13. Conformal field theories and critical phenomena

    International Nuclear Information System (INIS)

    Xu, Bowei

    1993-01-01

    In this article we present a brief review of the conformal symmetry and the two dimensional conformal quantum field theories. As concrete applications of the conformal theories to the critical phenomena in statistical systems, we calculate the value of central charge and the anomalous scale dimensions of the Z 2 symmetric quantum chain with boundary condition. The results are compatible with the prediction of the conformal field theories

  14. New conformations of linear polyubiquitin chains from crystallographic and solution-scattering studies expand the conformational space of polyubiquitin.

    Science.gov (United States)

    Thach, Trung Thanh; Shin, Donghyuk; Han, Seungsu; Lee, Sangho

    2016-04-01

    The conformational flexibility of linkage-specific polyubiquitin chains enables ubiquitylated proteins and their receptors to be involved in a variety of cellular processes. Linear or Met1-linked polyubiquitin chains, associated with nondegradational cellular signalling pathways, have been known to adopt multiple conformations from compact to extended conformations. However, the extent of such conformational flexibility remains open. Here, the crystal structure of linear Ub2 was determined in a more compact conformation than that of the previously known structure (PDB entry 3axc). The two structures differ significantly from each other, as shown by an r.m.s.d. between C(α) atoms of 3.1 Å. The compactness of the linear Ub2 structure in comparison with PDB entry 3axc is supported by smaller values of the radius of gyration (Rg; 18 versus 18.9 Å) and the maximum interatomic distance (Dmax; 55.5 versus 57.8 Å). Extra intramolecular hydrogen bonds formed among polar residues between the distal and proximal ubiquitin moieties seem to contribute to stabilization of the compact conformation of linear Ub2. An ensemble of three semi-extended and extended conformations of linear Ub2 was also observed by small-angle X-ray scattering (SAXS) analysis in solution. In addition, the conformational heterogeneity in linear polyubiquitin chains is clearly manifested by SAXS analyses of linear Ub3 and Ub4: at least three distinct solution conformations are observed in each chain, with the linear Ub3 conformations being compact. The results expand the extent of conformational space of linear polyubiquitin chains and suggest that changes in the conformational ensemble may be pivotal in mediating multiple signalling pathways.

  15. Initiation of conformal radiotherapy with a multileaf-collimator - An approach to clinical routine

    International Nuclear Information System (INIS)

    Bannach, B.; Doll, Th.; Pape, H.; Schmitt, G.

    1995-01-01

    The implementation of a three-dimensional conformal radiotherapy facility in the radiotherapy department of the Heinrich Heine University is described. Complex radiotherapy techniques with commercially available networked systems are introduced to improve clinical work. Over 18 month we have gained clinical experience with a PHILIPS Multileaf Collimator (MLC) mounted on a SL 25 linear accelerator. For a limited period the MLC was used as a conventional blocking device. The standard MLC-shapes are controlled with a stand-alone computer system. In addition, a three-dimensional treatment planning system (3-D-TPS / TMS-Radix, Helax AB) based on convolution/superposition algorithms was recently installed. Treatment optimization is achieved using static field arrangements with complete volumetric computerized tomographic patient data for 3-D-TPS. Conformal adaptation of the 95%-isodose to the Planning Target Volume (PTV, ICRU 50) results in MLC-field-shaping concerning size, position and contour to PTV-projection in beams-eye-view (BEV). Field prescription with defined leaf positions of the MLC-setting for geometrical beam shaping is transferred from TPS via TCP/IP. Patient treatment with complex coplanar and non-coplanar field arrangements is performed with an automatic set-up for gantry and collimator angle position contolled by a verification system. Quality assurance for treatment set-up is gained with a mega-voltage imaging device (MVI / PHILIPS SRI 100). Actual treatment outcome and accurate dose delivery for conformal therapy is verified by intercomparison of geometrical field matching of MVI and digitally reconstructed radiographs (DRR) for each delivered beam in BEV

  16. Industrial heat treatment of R-HPDC A356 automotive brake callipers

    CSIR Research Space (South Africa)

    Chauke, L

    2012-10-01

    Full Text Available Heat treatment of rheo-high pressure die cast (R-HPDC) A356 brake callipers has produced good mechanical properties on the laboratory scale. An industrial heat treatment is required to evaluate the applicability and conformance of the R-HPDC A356...

  17. Ward identities for conformal models

    International Nuclear Information System (INIS)

    Lazzarini, S.; Stora, R.

    1988-01-01

    Ward identities which express the symmetry of conformal models are treated. Diffeomorphism invariance or locally holomorphic coordinate transformations are used. Diffeomorphism invariance is then understood in terms of Riemannian geometry. Two different sets of Ward identities expressing diffeomorphism invariance in a conformally invariant way are found for the free bosonic string. Using a geometrical argument, the correct invariance for a large class of conformal models is given

  18. Variable-temperature NMR and conformational analysis of Oenothein B

    International Nuclear Information System (INIS)

    Santos, Suzana C.; Carvalho, Ariadne G.; Fortes, Gilmara A.C.; Ferri, Pedro H.; Oliveira, Anselmo E. de

    2014-01-01

    Oenothein B is a dimeric hydrolyzable tannin with a wide range of biological activities, such as antitumour, anti-inflammatory and antiviral. Its nuclear magnetic resonance (NMR) at room temperature show duplications and broadening of signals. Experiments of 1D and 2D NMR at lower temperatures were useful for the complete NMR assignments of all hydrogens and carbons. The 3D structure of the most stable conformer was determined for the first time by nuclear Overhauser effect spectroscopy (NOESY) experiment (-20 deg C) and density functional theory (DFT)(B3LYP/6-31G)/ polarizable continuum model (PCM) quantum chemical calculations. The favoured conformation showed a highly compacted geometry and a lack of symmetry, in which the two valoneoyl groups showed distinct conformational parameters and stabilities. (author)

  19. Variable-temperature NMR and conformational analysis of Oenothein B

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Suzana C.; Carvalho, Ariadne G.; Fortes, Gilmara A.C.; Ferri, Pedro H.; Oliveira, Anselmo E. de, [Universidade Federal de Goias (UFGO), Goiania, GO (Brazil). Instituto de Quimica

    2014-02-15

    Oenothein B is a dimeric hydrolyzable tannin with a wide range of biological activities, such as antitumour, anti-inflammatory and antiviral. Its nuclear magnetic resonance (NMR) at room temperature show duplications and broadening of signals. Experiments of 1D and 2D NMR at lower temperatures were useful for the complete NMR assignments of all hydrogens and carbons. The 3D structure of the most stable conformer was determined for the first time by nuclear Overhauser effect spectroscopy (NOESY) experiment (-20 deg C) and density functional theory (DFT)(B3LYP/6-31G)/ polarizable continuum model (PCM) quantum chemical calculations. The favoured conformation showed a highly compacted geometry and a lack of symmetry, in which the two valoneoyl groups showed distinct conformational parameters and stabilities. (author)

  20. Synthesis and conformational analysis of new arylated-diphenylurea derivatives related to sorafenib drug via Suzuki-Miyaura cross-coupling reaction

    Science.gov (United States)

    Al-Masoudi, Najim A.; Essa, Ali Hashem; Alwaaly, Ahmed A. S.; Saeed, Bahjat A.; Langer, Peter

    2017-10-01

    Sorafenib, is a relatively new cytostatic drug approved for the treatment of renal cell and hepatocellular carcinoma. The development of new sorafenib analogues offers the possibility of generating structures of increased potency. To this end, a series of arylated-diphenylurea analogues 17-31 were synthesized via Suzuki-Miyaura coupling reaction, related to sorafenib by treatment of three diarylureas 2-4 having 3-bromo, 4-chloro and 2-iodo groups with various arylboronic acids. Conformational analysis of the new arylated urea analogues has been investigated using MOPAC 2016 of semi empirical PM7 Hamiltonian computational method. Our results showed that all compounds preferred the trans-trans conformations. Compound 17 has been selected to calculate the torsional energy profiles for rotation around the urea bonds and found to be existed predominantly in the trans-trans conformation with only very minimal fluctuation in conformation.

  1. Conformity and statistical tolerancing

    Science.gov (United States)

    Leblond, Laurent; Pillet, Maurice

    2018-02-01

    Statistical tolerancing was first proposed by Shewhart (Economic Control of Quality of Manufactured Product, (1931) reprinted 1980 by ASQC), in spite of this long history, its use remains moderate. One of the probable reasons for this low utilization is undoubtedly the difficulty for designers to anticipate the risks of this approach. The arithmetic tolerance (worst case) allows a simple interpretation: conformity is defined by the presence of the characteristic in an interval. Statistical tolerancing is more complex in its definition. An interval is not sufficient to define the conformance. To justify the statistical tolerancing formula used by designers, a tolerance interval should be interpreted as the interval where most of the parts produced should probably be located. This tolerance is justified by considering a conformity criterion of the parts guaranteeing low offsets on the latter characteristics. Unlike traditional arithmetic tolerancing, statistical tolerancing requires a sustained exchange of information between design and manufacture to be used safely. This paper proposes a formal definition of the conformity, which we apply successively to the quadratic and arithmetic tolerancing. We introduce a concept of concavity, which helps us to demonstrate the link between tolerancing approach and conformity. We use this concept to demonstrate the various acceptable propositions of statistical tolerancing (in the space decentring, dispersion).

  2. Dissecting the large-scale galactic conformity

    Science.gov (United States)

    Seo, Seongu

    2018-01-01

    Galactic conformity is an observed phenomenon that galaxies located in the same region have similar properties such as star formation rate, color, gas fraction, and so on. The conformity was first observed among galaxies within in the same halos (“one-halo conformity”). The one-halo conformity can be readily explained by mutual interactions among galaxies within a halo. Recent observations however further witnessed a puzzling connection among galaxies with no direct interaction. In particular, galaxies located within a sphere of ~5 Mpc radius tend to show similarities, even though the galaxies do not share common halos with each other ("two-halo conformity" or “large-scale conformity”). Using a cosmological hydrodynamic simulation, Illustris, we investigate the physical origin of the two-halo conformity and put forward two scenarios. First, back-splash galaxies are likely responsible for the large-scale conformity. They have evolved into red galaxies due to ram-pressure stripping in a given galaxy cluster and happen to reside now within a ~5 Mpc sphere. Second, galaxies in strong tidal field induced by large-scale structure also seem to give rise to the large-scale conformity. The strong tides suppress star formation in the galaxies. We discuss the importance of the large-scale conformity in the context of galaxy evolution.

  3. Topics in conformal invariance and generalized sigma models

    International Nuclear Information System (INIS)

    Bernardo, L.M.; Lawrence Berkeley National Lab., CA

    1997-05-01

    This thesis consists of two different parts, having in common the fact that in both, conformal invariance plays a central role. In the first part, the author derives conditions for conformal invariance, in the large N limit, and for the existence of an infinite number of commuting classical conserved quantities, in the Generalized Thirring Model. The treatment uses the bosonized version of the model. Two different approaches are used to derive conditions for conformal invariance: the background field method and the Hamiltonian method based on an operator algebra, and the agreement between them is established. The author constructs two infinite sets of non-local conserved charges, by specifying either periodic or open boundary conditions, and he finds the Poisson Bracket algebra satisfied by them. A free field representation of the algebra satisfied by the relevant dynamical variables of the model is also presented, and the structure of the stress tensor in terms of free fields (and free currents) is studied in detail. In the second part, the author proposes a new approach for deriving the string field equations from a general sigma model on the world sheet. This approach leads to an equation which combines some of the attractive features of both the renormalization group method and the covariant beta function treatment of the massless excitations. It has the advantage of being covariant under a very general set of both local and non-local transformations in the field space. The author applies it to the tachyon, massless and first massive level, and shows that the resulting field equations reproduce the correct spectrum of a left-right symmetric closed bosonic string

  4. Entanglement evolution across a conformal interface

    Science.gov (United States)

    Wen, Xueda; Wang, Yuxuan; Ryu, Shinsei

    2018-05-01

    For two-dimensional conformal field theories (CFTs) in the ground state, it is known that a conformal interface along the entanglement cut can suppress the entanglement entropy from to , where L is the length of the subsystem A, and is the effective central charge which depends on the transmission property of the conformal interface. In this work, by making use of conformal mappings, we show that a conformal interface has the same effect on entanglement evolution in non-equilibrium cases, including global, local and certain inhomogeneous quantum quenches. I.e. a conformal interface suppresses the time evolution of entanglement entropy by effectively replacing the central charge c with , where is exactly the same as that in the ground state case. We confirm this conclusion by a numerical study on a critical fermion chain. Furthermore, based on the quasi-particle picture, we conjecture that this conclusion holds for an arbitrary quantum quench in CFTs, as long as the initial state can be described by a regularized conformal boundary state.

  5. Long, partial-short, and special conformal fields

    Energy Technology Data Exchange (ETDEWEB)

    Metsaev, R.R. [Department of Theoretical Physics, P.N. Lebedev Physical Institute,Leninsky prospect 53, Moscow 119991 (Russian Federation)

    2016-05-17

    In the framework of metric-like approach, totally symmetric arbitrary spin bosonic conformal fields propagating in flat space-time are studied. Depending on the values of conformal dimension, spin, and dimension of space-time, we classify all conformal field as long, partial-short, short, and special conformal fields. An ordinary-derivative (second-derivative) Lagrangian formulation for such conformal fields is obtained. The ordinary-derivative Lagrangian formulation is realized by using double-traceless gauge fields, Stueckelberg fields, and auxiliary fields. Gauge-fixed Lagrangian invariant under global BRST transformations is obtained. The gauge-fixed BRST Lagrangian is used for the computation of partition functions for all conformal fields. Using the result for the partition functions, numbers of propagating D.o.F for the conformal fields are also found.

  6. Probing the Conformational Landscape of Polyether Building Blocks in Supersonic Jets

    Science.gov (United States)

    Bocklitz, Sebastian; Hewett, Daniel M.; Zwier, Timothy S.; Suhm, Martin A.

    2016-06-01

    Polyethylene oxides (Polyethylene glycoles) and their phenoxy-capped analogs represent a prominent class of important polymers that are highly used as precursor molecules in supramolecular reactions. After a detailed study on the simplest representative (1,2-dimethoxyethane) [1], we present results on oligoethylene oxides with increasing chain lengths obtained by spontaneous Raman scattering in a supersonic jet. Through variation of stagnation pressure, carrier gas, nozzle distance and temperature we gain information on the conformational landscape as well as the mutual interconversion of low energy conformers. The obtained results are compared to state-of-the-art quantum chemical calculations. Additionally, we present UV as well as IR-UV and UV-UV double resonance studies on 1-methoxy-2-phenoxyethane in a supersonic jet. These complementary techniques allow for conformationally selective electronic and vibrational spectra in a closely related conformational landscape. [1] S. Bocklitz, M. A. Suhm, Constraining the Conformational Landscape of a Polyether Building Block by Raman Jet Spectroscopy, Z. Phys. Chem. 2015, 229, 1625-1648.

  7. Integrability of conformal fishnet theory

    Science.gov (United States)

    Gromov, Nikolay; Kazakov, Vladimir; Korchemsky, Gregory; Negro, Stefano; Sizov, Grigory

    2018-01-01

    We study integrability of fishnet-type Feynman graphs arising in planar four-dimensional bi-scalar chiral theory recently proposed in arXiv:1512.06704 as a special double scaling limit of gamma-deformed N = 4 SYM theory. We show that the transfer matrix "building" the fishnet graphs emerges from the R-matrix of non-compact conformal SU(2 , 2) Heisenberg spin chain with spins belonging to principal series representations of the four-dimensional conformal group. We demonstrate explicitly a relationship between this integrable spin chain and the Quantum Spectral Curve (QSC) of N = 4 SYM. Using QSC and spin chain methods, we construct Baxter equation for Q-functions of the conformal spin chain needed for computation of the anomalous dimensions of operators of the type tr( ϕ 1 J ) where ϕ 1 is one of the two scalars of the theory. For J = 3 we derive from QSC a quantization condition that fixes the relevant solution of Baxter equation. The scaling dimensions of the operators only receive contributions from wheel-like graphs. We develop integrability techniques to compute the divergent part of these graphs and use it to present the weak coupling expansion of dimensions to very high orders. Then we apply our exact equations to calculate the anomalous dimensions with J = 3 to practically unlimited precision at any coupling. These equations also describe an infinite tower of local conformal operators all carrying the same charge J = 3. The method should be applicable for any J and, in principle, to any local operators of bi-scalar theory. We show that at strong coupling the scaling dimensions can be derived from semiclassical quantization of finite gap solutions describing an integrable system of noncompact SU(2 , 2) spins. This bears similarities with the classical strings arising in the strongly coupled limit of N = 4 SYM.

  8. Maxwell equations in conformal invariant electrodynamics

    International Nuclear Information System (INIS)

    Fradkin, E.S.; AN SSSR, Novosibirsk. Inst. Avtomatiki i Ehlektrometrii); Kozhevnikov, A.A.; Palchik, M.Ya.; Pomeransky, A.A.

    1983-01-01

    We consider a conformal invariant formulation of quantum electrodynamics. Conformal invariance is achieved with a specific mathematical construction based on the indecomposable representations of the conformal group associated with the electromagnetic potential and current. As a corolary of this construction modified expressions for the 3-point Green functions are obtained which both contain transverse parts. They make it possible to formulate a conformal invariant skeleton perturbation theory. It is also shown that the Euclidean Maxwell equations in conformal electrodynamics are manifestations of its kinematical structure: in the case of the 3-point Green functions these equations follow (up to constants) from the conformal invariance while in the case of higher Green functions they are equivalent to the equality of the kernels of the partial wave expansions. This is the manifestation of the mathematical fast of a (partial) equivalence of the representations associated with the potential, current and the field tensor. (orig.)

  9. Conformal symmetries of FRW accelerating cosmologies

    International Nuclear Information System (INIS)

    Kehagias, A.; Riotto, A.

    2014-01-01

    We show that any accelerating Friedmann–Robertson–Walker (FRW) cosmology with equation of state w<−1/3 (and therefore not only a de Sitter stage with w=−1) exhibits three-dimensional conformal symmetry on future constant-time hypersurfaces if the bulk theory is invariant under bulk conformal Killing vectors. We also offer an alternative derivation of this result in terms of conformal Killing vectors and show that long wavelength comoving curvature perturbations of the perturbed FRW metric are just conformal Killing motions of the FRW background. We then extend the boundary conformal symmetry to the bulk for accelerating cosmologies. Our findings indicate that one can easily generate perturbations of scalar fields which are not only scale invariant, but also fully conformally invariant on super-Hubble scales. Measuring a scale-invariant power spectrum for the cosmological perturbation does not automatically imply that the universe went through a de Sitter stage

  10. pH-induced conformational change of the rotavirus VP4 spike: implications for cell entry and antibody neutralization.

    Science.gov (United States)

    Pesavento, Joseph B; Crawford, Sue E; Roberts, Ed; Estes, Mary K; Prasad, B V Venkataram

    2005-07-01

    The rotavirus spike protein, VP4, is a major determinant of infectivity and neutralization. Previously, we have shown that trypsin-enhanced infectivity of rotavirus involves a transformation of the VP4 spike from a flexible to a rigid bilobed structure. Here we show that at elevated pH the spike undergoes a drastic, irreversible conformational change and becomes stunted, with a pronounced trilobed appearance. These particles with altered spikes, at a normal pH of 7.5, despite the loss of infectivity and the ability to hemagglutinate, surprisingly exhibit sialic acid (SA)-independent cell binding in contrast to the SA-dependent cell binding exhibited by native virions. Remarkably, a neutralizing monoclonal antibody that remains bound to spikes throughout the pH changes (pH 7 to 11 and back to pH 7) completely prevents this conformational change, preserving the SA-dependent cell binding and hemagglutinating functions of the virion. A hypothesis that emerges from the present study is that high-pH treatment triggers a conformational change that mimics a post-SA-attachment step to expose an epitope recognized by a downstream receptor in the rotavirus cell entry process. This process involves sequential interactions with multiple receptors, and the mechanism by which the antibody neutralizes is by preventing this conformational change.

  11. Dosimetric Comparison of Three Dimensional Conformal Radiation Radiotherapy and Helical Tomotherapy Partial Breast Cancer

    International Nuclear Information System (INIS)

    Kim, Dae Woong; Kim, Jong Won; Choi, Yun Kyeong; Kim, Jung Soo; Hwang, Jae Woong; Jeong, Kyeong Sik; Choi, Gye Suk

    2008-01-01

    The goal of radiation treatment is to deliver a prescribed radiation dose to the target volume accurately while minimizing dose to normal tissues. In this paper, we comparing the dose distribution between three dimensional conformal radiation radiotherapy (3D-CRT) and helical tomotherapy (TOMO) plan for partial breast cancer. Twenty patients were included in the study, and plans for two techniques were developed for each patient (left breast:10 patients, right breast:10 patients). For each patient 3D-CRT planning was using pinnacle planning system, inverse plan was made using Tomotherapy Hi-Art system and using the same targets and optimization goals. We comparing the Homogeneity index (HI), Conformity index (CI) and sparing of the organs at risk for dose-volume histogram. Whereas the HI, CI of TOMO was significantly better than the other, 3D-CRT was observed to have significantly poorer HI, CI. The percentage ipsilateral non-PTV breast volume that was delivered 50% of the prescribed dose was 3D-CRT (mean: 40.4%), TOMO (mean: 18.3%). The average ipsilateral lung volume percentage receiving 20% of the PD was 3D-CRT (mean: 4.8%), TOMO (mean: 14.2), concerning the average heart volume receiving 20% and 10% of the PD during treatment of left breast cancer 3D-CRT (mean: 1.6%, 3.0%), TOMO (mean: 9.7%, 26.3%) In summary, 3D-CRT and TOMO techniques were found to have acceptable PTV coverage in our study. However, in TOMO, high conformity to the PTV and effective breast tissue sparing was achieved at the expense of considerable dose exposure to the lung and heart.

  12. Switch region for pathogenic structural change in conformational disease and its prediction.

    Directory of Open Access Journals (Sweden)

    Xin Liu

    2010-01-01

    Full Text Available Many diseases are believed to be related to abnormal protein folding. In the first step of such pathogenic structural changes, misfolding occurs in regions important for the stability of the native structure. This destabilizes the normal protein conformation, while exposing the previously hidden aggregation-prone regions, leading to subsequent errors in the folding pathway. Sites involved in this first stage can be deemed switch regions of the protein, and can represent perfect binding targets for drugs to block the abnormal folding pathway and prevent pathogenic conformational changes. In this study, a prediction algorithm for the switch regions responsible for the start of pathogenic structural changes is introduced. With an accuracy of 94%, this algorithm can successfully find short segments covering sites significant in triggering conformational diseases (CDs and is the first that can predict switch regions for various CDs. To illustrate its effectiveness in dealing with urgent public health problems, the reason of the increased pathogenicity of H5N1 influenza virus is analyzed; the mechanisms of the pandemic swine-origin 2009 A(H1N1 influenza virus in overcoming species barriers and in infecting large number of potential patients are also suggested. It is shown that the algorithm is a potential tool useful in the study of the pathology of CDs because: (1 it can identify the origin of pathogenic structural conversion with high sensitivity and specificity, and (2 it provides an ideal target for clinical treatment.

  13. The treatment of nonpalpable PSA-detected adenocarcinoma of the prostate with 3-dimensional conformal radiation therapy

    International Nuclear Information System (INIS)

    Horwitz, Eric M.; Hanlon, Alexandra L.; Pinover, Wayne H.; Hanks, Gerald E.

    1998-01-01

    Purpose: We reviewed our institution's experience treating patients with nonpalpable PSA-detected prostate cancer with three-dimensional conformal radiation therapy (3DCRT) to determine prognostic factors that predict for biochemical-free survival (bNED) control and present the bNED control rates. Methods and Materials: Between May 1, 1990 and November 30, 1994, 160 patients with nonpalpable PSA-detected prostate cancer received 3DCRT at Fox Chase Cancer Center (median total dose 73 Gy; range: 67-78 Gy). bNED failure was defined as three consecutive increases in posttreatment PSA after achieving a nadir. bNED failure was recorded as the time midway between the nadir and the first consecutive rising PSA. Five-year actuarial rates of bNED control were calculated for pretreatment PSA (0-9.9 vs. 10-19.9 vs. ≥ 20 ng/ml), Gleason score (2-6 vs. 7-10), treatment field size (prostate vs. small pelvis), age ( 73 Gy) using Kaplan-Meier methods and compared using the Log rank test. The Cox model was used to multivariately establish independent predictors based on significant univariate factors. Median follow-up was 39 months (range: 2-84 months). Results: The 5-year actuarial rate of bNED control was 86% for the entire group of patients. The Cox Proportional Hazards model demonstrated that pretreatment PSA was an independent predictor of bNED control. Treatment field size was marginally predictive. There was no difference in bNED control when patients were stratified by the number of lobes positive for disease. Statistically different rates of bNED control were seen when the patients with nonpalpable disease were univariately compared to T2b and T2c patients. Three patients experienced Grade 3-4 genitourinary (GU) toxicity and 3 patients experienced Grade 3-4 gastrointestinal (GI) toxicity. Conclusions: Patients with nonpalpable PSA-detected prostate cancer can be effectively treated with 3DCRT with minimal morbidity and high rates of bNED control at 5 years. Pretreatment

  14. 40 CFR 52.2133 - General conformity.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false General conformity. 52.2133 Section 52...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) South Carolina § 52.2133 General conformity. The General Conformity regulations adopted into the South Carolina State Implementation Plan which...

  15. Treatment planning for radiotherapy with very high-energy electron beams and comparison of VHEE and VMAT plans

    International Nuclear Information System (INIS)

    Bazalova-Carter, Magdalena; Qu, Bradley; Palma, Bianey; Jensen, Christopher; Maxim, Peter G.; Loo, Billy W.; Hårdemark, Björn; Hynning, Elin

    2015-01-01

    Purpose: The aim of this work was to develop a treatment planning workflow for rapid radiotherapy delivered with very high-energy electron (VHEE) scanning pencil beams of 60–120 MeV and to study VHEE plans as a function of VHEE treatment parameters. Additionally, VHEE plans were compared to clinical state-of-the-art volumetric modulated arc therapy (VMAT) photon plans for three cases. Methods: VHEE radiotherapy treatment planning was performed by linking EGSnrc Monte Carlo (MC) dose calculations with inverse treatment planning in a research version of RayStation. In order to study the effect of VHEE treatment parameters on VHEE dose distributions, a MATLAB graphical user interface (GUI) for calculation of VHEE MC pencil beam doses was developed. Through the GUI, pediatric case MC simulations were run for a number of beam energies (60, 80, 100, and 120 MeV), number of beams (13, 17, and 36), pencil beam spot (0.1, 1.0, and 3.0 mm) and grid (2.0, 2.5, and 3.5 mm) sizes, and source-to-axis distance, SAD (40 and 50 cm). VHEE plans for the pediatric case calculated with the different treatment parameters were optimized and compared. Furthermore, 100 MeV VHEE plans for the pediatric case, a lung, and a prostate case were calculated and compared to the clinically delivered VMAT plans. All plans were normalized such that the 100% isodose line covered 95% of the target volume. Results: VHEE beam energy had the largest effect on the quality of dose distributions of the pediatric case. For the same target dose, the mean doses to organs at risk (OARs) decreased by 5%–16% when planned with 100 MeV compared to 60 MeV, but there was no further improvement in the 120 MeV plan. VHEE plans calculated with 36 beams outperformed plans calculated with 13 and 17 beams, but to a more modest degree (<8%). While pencil beam spacing and SAD had a small effect on VHEE dose distributions, 0.1–3 mm pencil beam sizes resulted in identical dose distributions. For the 100 MeV VHEE pediatric

  16. 40 CFR 91.106 - Certificate of conformity.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Certificate of conformity. 91.106... Provisions § 91.106 Certificate of conformity. (a) Every manufacturer of a new marine SI engine produced... obtain a certificate of conformity covering each engine family. The certificate of conformity must be...

  17. 40 CFR 52.938 - General conformity.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false General conformity. 52.938 Section 52...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Kentucky § 52.938 General conformity. The General Conformity regulations were submitted on November 10, 1995, and adopted into the Kentucky State...

  18. 40 CFR 51.854 - Conformity analysis.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false Conformity analysis. 51.854 Section 51... FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS Determining Conformity of General Federal Actions to State or Federal Implementation Plans § 51.854 Conformity analysis. Link to an...

  19. Lie algebra of conformal Killing–Yano forms

    International Nuclear Information System (INIS)

    Ertem, Ümit

    2016-01-01

    We provide a generalization of the Lie algebra of conformal Killing vector fields to conformal Killing–Yano forms. A new Lie bracket for conformal Killing–Yano forms that corresponds to slightly modified Schouten–Nijenhuis bracket of differential forms is proposed. We show that conformal Killing–Yano forms satisfy a graded Lie algebra in constant curvature manifolds. It is also proven that normal conformal Killing–Yano forms in Einstein manifolds also satisfy a graded Lie algebra. The constructed graded Lie algebras reduce to the graded Lie algebra of Killing–Yano forms and the Lie algebras of conformal Killing and Killing vector fields in special cases. (paper)

  20. Universal hydrodynamics of non-conformal branes

    International Nuclear Information System (INIS)

    Kanitscheider, Ingmar; Skenderis, Kostas

    2009-01-01

    We examine the hydrodynamic limit of non-conformal branes using the recently developed precise holographic dictionary. We first streamline the discussion of holography for backgrounds that asymptote locally to non-conformal brane solutions by showing that all such solutions can be obtained from higher dimensional asymptotically locally AdS solutions by suitable dimensional reduction and continuation in the dimension. As a consequence, many holographic results for such backgrounds follow from the corresponding results of the Asymptotically AdS case. In particular, the hydrodynamics of non-conformal branes is fully determined in terms of conformal hydrodynamics. Using previous results on the latter we predict the form of the non-conformal hydrodynamic stress tensor to second order in derivatives. Furthermore we show that the ratio between bulk and shear viscosity is fixed by the generalized conformal structure to be ζ/η = 2(1/(d-1)-c s 2 ), where c s is the speed of sound in the fluid.

  1. Operator algebras and conformal field theory

    International Nuclear Information System (INIS)

    Gabbiani, F.; Froehlich, J.

    1993-01-01

    We define and study two-dimensional, chiral conformal field theory by the methods of algebraic field theory. We start by characterizing the vacuum sectors of such theories and show that, under very general hypotheses, their algebras of local observables are isomorphic to the unique hyperfinite type III 1 factor. The conformal net determined by the algebras of local observables is proven to satisfy Haag duality. The representation of the Moebius group (and presumably of the entire Virasoro algebra) on the vacuum sector of a conformal field theory is uniquely determined by the Tomita-Takesaki modular operators associated with its vacuum state and its conformal net. We then develop the theory of Mebius covariant representations of a conformal net, using methods of Doplicher, Haag and Roberts. We apply our results to the representation theory of loop groups. Our analysis is motivated by the desire to find a 'background-independent' formulation of conformal field theories. (orig.)

  2. 47 CFR 2.906 - Declaration of Conformity.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Declaration of Conformity. 2.906 Section 2.906... Conformity. (a) A Declaration of Conformity is a procedure where the responsible party, as defined in § 2.909... of Conformity attaches to all items subsequently marketed by the responsible party which are...

  3. Naturality in conformal field theory

    International Nuclear Information System (INIS)

    Moore, G.; Seiberg, N.

    1989-01-01

    We discuss constraints on the operator product coefficients in diagonal and nondiagonal rational conformal field theories. Nondiagonal modular invariants always arise from automorphisms of the fusion rule algebra or from extensions of the chiral algebra. Moreover, when the chiral algebra has been maximally extended a strong form of the naturality principle of field theory can be proven for rational conformal field theory: operator product coefficients vanish if and only if the corresponding fusion rules vanish; that is, if and only if the vanishing can be understood in terms of a symmetry. We illustrate these ideas with several examples. We also generalize our ideas about rational conformal field theories to a larger class of theories: 'quasi-rational conformal field theories' and we explore some of their properties. (orig.)

  4. Hippocampal sparing radiotherapy for pediatric medulloblastoma: impact of treatment margins and treatment technique.

    Science.gov (United States)

    Brodin, N Patrik; Munck af Rosenschöld, Per; Blomstrand, Malin; Kiil-Berthlesen, Anne; Hollensen, Christian; Vogelius, Ivan R; Lannering, Birgitta; Bentzen, Søren M; Björk-Eriksson, Thomas

    2014-04-01

    We investigated how varying the treatment margin and applying hippocampal sparing and proton therapy impact the risk of neurocognitive impairment in pediatric medulloblastoma patients compared with current standard 3D conformal radiotherapy. We included 17 pediatric medulloblastoma patients to represent the variability in tumor location relative to the hippocampal region. Treatment plans were generated using 3D conformal radiotherapy, hippocampal sparing intensity-modulated radiotherapy, and spot-scanned proton therapy, using 3 different treatment margins for the conformal tumor boost. Neurocognitive impairment risk was estimated based on dose-response models from pediatric CNS malignancy survivors and compared among different margins and treatment techniques. Mean hippocampal dose and corresponding risk of cognitive impairment were decreased with decreasing treatment margins (P < .05). The largest risk reduction, however, was seen when applying hippocampal sparing proton therapy-the estimated risk of impaired task efficiency (95% confidence interval) was 92% (66%-98%), 81% (51%-95%), and 50% (30%-70%) for 3D conformal radiotherapy, intensity-modulated radiotherapy, and proton therapy, respectively, for the smallest boost margin and 98% (78%-100%), 90% (60%-98%), and 70% (39%-90%) if boosting the whole posterior fossa. Also, the distance between the closest point of the planning target volume and the center of the hippocampus can be used to predict mean hippocampal dose for a given treatment technique. We estimate a considerable clinical benefit of hippocampal sparing radiotherapy. In choosing treatment margins, the tradeoff between margin size and risk of neurocognitive impairment quantified here should be considered.

  5. 21 CFR 26.70 - Conformity assessment bodies.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Conformity assessment bodies. 26.70 Section 26.70...Frameworkâ Provisions § 26.70 Conformity assessment bodies. Each party recognizes that the conformity... conformity in relation to its requirements as specified in subpart B of this part. The parties shall specify...

  6. Conformational analysis of lignin models

    International Nuclear Information System (INIS)

    Santos, Helio F. dos

    2001-01-01

    The conformational equilibrium for two 5,5' biphenyl lignin models have been analyzed using a quantum mechanical semiempirical method. The gas phase and solution structures are discussed based on the NMR and X-ray experimental data. The results obtained showed that the observed conformations are solvent-dependent, being the geometries and the thermodynamic properties correlated with the experimental information. This study shows how a systematic theoretical conformational analysis can help to understand chemical processes at a molecular level. (author)

  7. On the linear conformal gravitation

    International Nuclear Information System (INIS)

    Pal'chik, M.Ya.; Fradkin, E.S.

    1984-01-01

    Conformal gravitation is analyzed under the assumption that its solution possesses the property of conformal symmetry. This assumption has sense in the case of small distances and only for definite types of matter fields, namely: at special choice of matter fields and their interactions, providing a lack of conformal anomalies; or at definite magnitudes of binding constants, coinciding with the zeroes of the Gell-Mann-Low function. The field equations, of the group-theoretical natura are obtained

  8. Conformal Symmetry Patterns in Baryon Spectra

    International Nuclear Information System (INIS)

    Kirchbach, Mariana; Compean, Cliffor B

    2011-01-01

    Attention is drawn to the fact that the spectra of the baryons of the lightest flavors, the nucleon and the Δ, carry quantum numbers characteristic for an unitary representation of the conformal group. We show that the above phenomenon is well explained for baryons whose internal structure is dominated by a quark-diquark configuration that resides in a conformally compactified Minkowski space time, R 1 x S 3 , and is described by means of the conformal scale equation there. The R 1 x S 3 space-time represents the boundary of the conformally compactified AdS 5 , on which one expects to encounter a conformal theory in accord with the gauge-gravity duality. Within this context, our model is congruent with AdS 5 /CFT 4 .

  9. Interrogating the activities of conformational deformed enzyme by single-molecule fluorescence-magnetic tweezers microscopy

    Science.gov (United States)

    Guo, Qing; He, Yufan; Lu, H. Peter

    2015-01-01

    Characterizing the impact of fluctuating enzyme conformation on enzymatic activity is critical in understanding the structure–function relationship and enzymatic reaction dynamics. Different from studying enzyme conformations under a denaturing condition, it is highly informative to manipulate the conformation of an enzyme under an enzymatic reaction condition while monitoring the real-time enzymatic activity changes simultaneously. By perturbing conformation of horseradish peroxidase (HRP) molecules using our home-developed single-molecule total internal reflection magnetic tweezers, we successfully manipulated the enzymatic conformation and probed the enzymatic activity changes of HRP in a catalyzed H2O2–amplex red reaction. We also observed a significant tolerance of the enzyme activity to the enzyme conformational perturbation. Our results provide a further understanding of the relation between enzyme behavior and enzymatic conformational fluctuation, enzyme–substrate interactions, enzyme–substrate active complex formation, and protein folding–binding interactions. PMID:26512103

  10. Conformational cooling and conformation selective aggregation in dimethyl sulfite isolated in solid rare gases

    OpenAIRE

    Borba, Ana; Gómez-Zavaglia, Andrea; Fausto, Rui

    2006-01-01

    Dimethyl sulfite has three conformers of low energy, GG, GT and GG0, which have significant populations in the gas phase at room temperature. According to theoretical predictions, the GT and GG0 conformers are higher in energy than the GG conformer by 0.83 and 1.18 kJ molK1, respectively, while the barriers associated with the GG0/GT and GT/GG isomerizations are 1.90 and 9.64 kJ molK1, respectively. Experimental data obtained for the compound isolated in solid argon, krypton and xenon demonst...

  11. Literature-based recommendations for treatment planning and execution in high-dose radiotherapy for lung cancer

    International Nuclear Information System (INIS)

    Senan, Suresh; De Ruysscher, Dirk; Giraud, Philippe; Mirimanoff, Rene; Budach, Volker

    2004-01-01

    Background and purpose: To review the literature on techniques used in high-dose radiotherapy of lung cancer in order to develop recommendations for clinical practice and for use in research protocols. Patients and methods: A literature search was performed for articles and abstracts that were considered both clinically relevant and practical to use. The relevant information was arbitrarily categorized under the following headings: patient positioning, CT scanning, incorporating tumour mobility, definition of target volumes, radiotherapy planning, treatment delivery, and scoring of response and toxicity. Results: Recommendations were made for each of the above steps from the published literature. Although most of the recommended techniques have yet to be evaluated in multicenter clinical trials, their use in high-dose radiotherapy to the thorax appears to be rational on the basis of current evidence. Conclusions: Recommendations for the clinical implementation of high-dose conformal radiotherapy for lung tumours were identified in the literature. Procedures that are still considered to be investigational were also highlighted

  12. Study of conformation and dynamic of surfactant molecules in graphite oxide via NMR

    Energy Technology Data Exchange (ETDEWEB)

    Ai, X.Q. [Jiangsu Second Normal University, College of Physics and Electronic Engineering, Nanjing (China); Ma, L.G. [Nanjing Xiaozhuang University, School of Electronic Engineering, Nanjing (China)

    2016-08-15

    The conformation and dynamic of surfactant in graphite oxide (GO) was investigated by solid-state {sup 13}C magic-angle-spinning NMR and {sup 1}H-{sup 13}C cross-polarization/magic-angle-spinning NMR spectra. The conformation ordering of the alkyl chains in the confined system shows strong dependence on its orientation. While the alkyl chains parallel to the GO layer in lateral monolayer arrangement are in gauche conformation in addition to a small amount of all-trans conformation, those with orientation radiating away from the GO in paraffin bilayer arrangement is in all-trans conformation in addition to some gauche conformation even though high-order diffraction peaks appears. NMR results suggest that the least mobile segment is located at the GO-surfactant interface corresponding to the N-methylene group. Further from it, the mobility of the alkyl chain increases. The terminal methyl and N-methyl carbon groups have the highest mobile. The chains in all-trans conformational state are characterized as more rigid than chains with gauche conformation; each segment of the confined alkyl chains with the lateral monolayer arrangement exhibits less mobility as compared to that with the paraffin bilayer arrangement. (orig.)

  13. Accelerated partial breast irradiation using robotic radiotherapy: a dosimetric comparison with tomotherapy and three-dimensional conformal radiotherapy.

    Science.gov (United States)

    Rault, Erwann; Lacornerie, Thomas; Dang, Hong-Phuong; Crop, Frederik; Lartigau, Eric; Reynaert, Nick; Pasquier, David

    2016-02-27

    Accelerated partial breast irradiation (APBI) is a new breast treatment modality aiming to reduce treatment time using hypo fractionation. Compared to conventional whole breast irradiation that takes 5 to 6 weeks, APBI is reported to induce worse cosmetic outcomes both when using three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT). These late normal tissue effects may be attributed to the dose volume effect because a large portion of the non-target breast tissue volume (NTBTV) receives a high dose. In the context of APBI, non-coplanar beams could spare the NTBTV more efficiently. This study evaluates the dosimetric benefit of using the Cyberknife (CK) for APBI in comparison to IMRT (Tomotherapy) and three dimensional conformal radiotherapy (3D-CRT). The possibility of using surgical clips, implanted during surgery, to track target movements is investigated first. A phantom of a female thorax was designed in-house using the measurements of 20 patients. Surgical clips of different sizes were inserted inside the breast. A treatment plan was delivered to the mobile and immobile phantom. The motion compensation accuracy was evaluated using three radiochromic films inserted inside the breast. Three dimensional conformal radiotherapy (3D-CRT), Tomotherapy (TOMO) and CK treatment plans were calculated for 10 consecutive patients who received APBI in Lille. To ensure a fair comparison of the three techniques, margins applied to the CTV were set to 10 mm. However, a second CK plan was prepared using 3 mm margins to evaluate the benefits of motion compensation. Only the larger clips (VITALITEC Medium-Large) could be tracked inside the larger breast (all gamma indices below 1 for 1 % of the maximum dose and 1 mm). All techniques meet the guidelines defined in the NSABP/RTOG and SHARE protocols. As the applied dose volume constraints are very strong, insignificant dosimetric differences exist between techniques regarding the PTV

  14. Accelerated partial breast irradiation using robotic radiotherapy: a dosimetric comparison with tomotherapy and three-dimensional conformal radiotherapy

    International Nuclear Information System (INIS)

    Rault, Erwann; Lacornerie, Thomas; Dang, Hong-Phuong; Crop, Frederik; Lartigau, Eric; Reynaert, Nick; Pasquier, David

    2016-01-01

    Accelerated partial breast irradiation (APBI) is a new breast treatment modality aiming to reduce treatment time using hypo fractionation. Compared to conventional whole breast irradiation that takes 5 to 6 weeks, APBI is reported to induce worse cosmetic outcomes both when using three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT). These late normal tissue effects may be attributed to the dose volume effect because a large portion of the non-target breast tissue volume (NTBTV) receives a high dose. In the context of APBI, non-coplanar beams could spare the NTBTV more efficiently. This study evaluates the dosimetric benefit of using the Cyberknife (CK) for APBI in comparison to IMRT (Tomotherapy) and three dimensional conformal radiotherapy (3D-CRT). The possibility of using surgical clips, implanted during surgery, to track target movements is investigated first. A phantom of a female thorax was designed in-house using the measurements of 20 patients. Surgical clips of different sizes were inserted inside the breast. A treatment plan was delivered to the mobile and immobile phantom. The motion compensation accuracy was evaluated using three radiochromic films inserted inside the breast. Three dimensional conformal radiotherapy (3D-CRT), Tomotherapy (TOMO) and CK treatment plans were calculated for 10 consecutive patients who received APBI in Lille. To ensure a fair comparison of the three techniques, margins applied to the CTV were set to 10 mm. However, a second CK plan was prepared using 3 mm margins to evaluate the benefits of motion compensation. Only the larger clips (VITALITEC Medium-Large) could be tracked inside the larger breast (all gamma indices below 1 for 1 % of the maximum dose and 1 mm). All techniques meet the guidelines defined in the NSABP/RTOG and SHARE protocols. As the applied dose volume constraints are very strong, insignificant dosimetric differences exist between techniques regarding the PTV

  15. Thickenings and conformal gravity

    Science.gov (United States)

    Lebrun, Claude

    1991-07-01

    A twistor correspondence is given for complex conformal space-times with vanishing Bach and Eastwood-Dighton tensors; when the Weyl curvature is algebraically general, these equations are precisely the conformal version of Einstein's vacuum equations with cosmological constant. This gives a fully curved version of the linearized correspondence of Baston and Mason [B-M].

  16. Thickenings and conformal gravity

    International Nuclear Information System (INIS)

    LeBrun, C.

    1991-01-01

    A twistor correspondence is given for complex conformal space-times with vanishing Bach and Eastwood-Dighton tensors; when the Weyl curvature is algebraically general, these equations are precisely the conformal version of Einstein's vacuum equations with cosmological constant. This gives a fully curved version of the linearized correspondence of Baston and Mason [B-M]. (orig.)

  17. Evaluation of the treatment planning system of three-dimensional conformal external radiotherapy in Hospital Mexico of San Jose, Costa Rica

    International Nuclear Information System (INIS)

    Venegas Rojas, Deybith

    2014-01-01

    An evaluation and analysis are realized of dosimetry of the treatment planning system (TPS) of three-dimensional conformal external radiotherapy in the Servicio de Radioterapia of the Hospital Mexico of Costa Rica. An evaluation procedure is proposed based on IAEA-TECDOC-1540 document, and may continue to be applied periodically in this or other radiotherapy services. Tests realized have checked the representation of distances and electronics densities transferred to the TPS, match with those of real objects. The 16 tests applied have represented situations of real treatments with different configurations and beam modifiers in the equipment used daily. The tests have measured the absorbed dose to water in different significant points at different depths, using photon beams of 6 MeV and 18 MeV. The physical parameters of the tests were simulated. The absorbed dose has been calculated at specified points. The XiO and Eclipse TPS have been used with the calculation algorithms: Superposition, Convolution and AAA. The results of the calculations are evaluated with statistical methods and comparing them with the measurements of absorbed dose. A generalized tendency has been detected toward negative relative errors, implying an underestimation of the dose by the TPS; due to a difference found in the accelerator output factor respect to its commissioning. The AAA algorithm has determined a better performance, although with greater difficulties of calculus in the region of build-up. Convolution and Superposition algorithms have had similar performances and both have presented problems in high depths and out of edges of the fields. The result of the dosimetric evaluation has been satisfactory in real conditions of equipment; but several particularities have been found that should be reviewed and adjusted. The precision of the TPS has been adequate in the majority of situations important for treatment planning. [author] [es

  18. Dosimetric effect on pediatric conformal treatment plans using dynamic jaw with Tomotherapy HDA.

    Science.gov (United States)

    Han, Eun Young; Kim, Dong-Wook; Zhang, Xin; Penagaricano, Jose; Liang, Xiaoying; Hardee, Matthew; Morrill, Steve; Ratanatharathorn, Vaneerat

    2015-01-01

    It is important to minimize the radiation dose delivered to healthy tissues in pediatric cancer treatment because of the risk of secondary malignancies. Tomotherapy HDA provides a dynamic jaw (DJ) delivery mode that creates a sharper penumbra at the craniocaudal ends of a target in addition to a fixed jaw (FJ) delivery mode. The purpose of this study was to evaluate its dosimetric effect on the pediatric cancer cases. We included 6 pediatric cases in this study. The dose profiles and plan statistics—target dose conformity, uniformity, organ-at-risk (OAR) mean dose, beam-on time, and integral dose—were compared for each case. Consequently, the target dose coverage and uniformity were similar for different jaw settings. The OAR dose sparing depended on its relative location to the target and disease sites. For example, in the head and neck cancer cases, the brain stem dose using DJ 2.5 was reduced by more than two-fold (2.4 Gy vs. 6.3 Gy) than that obtained with FJ 2.5. The integral dose with DJ 2.5 decreased by more than 9% compared with that with FJ 2.5. Thus, using dynamic jaw in pediatric cases could be critical to reduce a probability of a secondary malignancy. Copyright © 2015 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  19. Conformal symmetry inheritance in null fluid spacetimes

    International Nuclear Information System (INIS)

    Tupper, B O J; Keane, A J; Hall, G S; Coley, A A; Carot, J

    2003-01-01

    We define inheriting conformal Killing vectors for null fluid spacetimes and find the maximum dimension of the associated inheriting Lie algebra. We show that for non-conformally flat null fluid spacetimes, the maximum dimension of the inheriting algebra is seven and for conformally flat null fluid spacetimes the maximum dimension is eight. In addition, it is shown that there are two distinct classes of non-conformally flat generalized plane wave spacetimes which possess the maximum dimension, and one class in the conformally flat case

  20. Conformal maps between pseudo-Finsler spaces

    Science.gov (United States)

    Voicu, Nicoleta

    The paper aims to initiate a systematic study of conformal mappings between Finsler spacetimes and, more generally, between pseudo-Finsler spaces. This is done by extending several results in pseudo-Riemannian geometry which are necessary for field-theoretical applications and by proposing a technique that reduces some problems involving pseudo-Finslerian conformal vector fields to their pseudo-Riemannian counterparts. Also, we point out, by constructing classes of examples, that conformal groups of flat (locally Minkowskian) pseudo-Finsler spaces can be much richer than both flat Finslerian and pseudo-Euclidean conformal groups.

  1. Acute and late side-effects of conventional and conformal pelvic radiotherapy for cervical and endometrial cancer

    International Nuclear Information System (INIS)

    Izmajlowicz, B.; Komafel, J.

    2010-01-01

    Aim of the study. The purpose of this prospective study was to analyze and compare acute and late side-effects observed in patients with cervical and endometrial cancer treated with conventional 2-dimensional (2D) and conformal 3-dimensional (3D) pelvic radiotherapy. Patients and method. 50 patients treated with conventional pelvic radiotherapy and 50 patients treated with conformal pelvic radiotherapy at the Clinical Department of Gynecological Radiotherapy of the Lower Silesian Oncology Center between November 2004 and October 2005 were entered into a prospective study. We assessed Radiotherapy side-effects according to EORTCIRTOG, performance status according to the WHO, Body Mass Index and hematologic parameters during radiotherapy and one year after treatment. Results. Performance status acc. to the WHO was significantly better in the conformal arm. Anemia and nausea were more frequent in the conventional arm. In both the study groups acute gastrointestinal and genitourinary morbidity was more frequent than late morbidity and performance status was better after than before radiotherapy. Mean BMI was lower after radiotherapy than before treatment. Conclusions. Conformal pelvic radiotherapy in patients with cervical and endometrial cancer is less toxic than conventional pelvic radiotherapy which is also confirmed by the performance status. (authors)

  2. Transportation Conformity

    Science.gov (United States)

    This section provides information on: current laws, regulations and guidance, policy and technical guidance, project-level conformity, general information, contacts and training, adequacy review of SIP submissions

  3. Extended conformal algebras

    International Nuclear Information System (INIS)

    Goddard, Peter

    1990-01-01

    The algebra of the group of conformal transformations in two dimensions consists of two commuting copies of the Virasoro algebra. In many mathematical and physical contexts, the representations of ν which are relevant satisfy two conditions: they are unitary and they have the ''positive energy'' property that L o is bounded below. In an irreducible unitary representation the central element c takes a fixed real value. In physical contexts, the value of c is a characteristic of a theory. If c < 1, it turns out that the conformal algebra is sufficient to ''solve'' the theory, in the sense of relating the calculation of the infinite set of physically interesting quantities to a finite subset which can be handled in principle. For c ≥ 1, this is no longer the case for the algebra alone and one needs some sort of extended conformal algebra, such as the superconformal algebra. It is these algebras that this paper aims at addressing. (author)

  4. Families and degenerations of conformal field theories

    Energy Technology Data Exchange (ETDEWEB)

    Roggenkamp, D.

    2004-09-01

    In this work, moduli spaces of conformal field theories are investigated. In the first part, moduli spaces corresponding to current-current deformation of conformal field theories are constructed explicitly. For WZW models, they are described in detail, and sigma model realizations of the deformed WZW models are presented. The second part is devoted to the study of boundaries of moduli spaces of conformal field theories. For this purpose a notion of convergence of families of conformal field theories is introduced, which admits certain degenerated conformal field theories to occur as limits. To such a degeneration of conformal field theories, a degeneration of metric spaces together with additional geometric structures can be associated, which give rise to a geometric interpretation. Boundaries of moduli spaces of toroidal conformal field theories, orbifolds thereof and WZW models are analyzed. Furthermore, also the limit of the discrete family of Virasoro minimal models is investigated. (orig.)

  5. A study of the effects of internal organ motion on dose escalation in conformal prostate treatments

    International Nuclear Information System (INIS)

    Happersett, Laura; Mageras, Gig S.; Zelefsky, Michael J.; Burman, Chandra M.; Leibel, Steven A.; Chui Chen; Fuks, Zvi; Bull, Sarah; Ling, C. Clifton; Kutcher, Gerald J.

    2003-01-01

    Background and purpose: To assess the effect of internal organ motion on the dose distributions and biological indices for the target and non-target organs for three different conformal prostate treatment techniques. Materials and methods: We examined three types of treatment plans in 20 patients: (1) a six field plan, with a prescribed dose of 75.6 Gy; (2) the same six field plan to 72 Gy followed by a boost to 81 Gy; and (3) a five field plan with intensity modulated beams delivering 81 Gy. Treatment plans were designed using an initial CT data set (planning) and applied to three subsequent CT scans (treatment). The treatment CT contours were used to represent patient specific organ displacement; in addition, the dose distribution was convolved with a Gaussian distribution to model random setup error. Dose-volume histograms were calculated using an organ deformation model in which the movement between scans of individual points interior to the organs was tracked and the dose accumulated. The tumor control probability (TCP) for the prostate and proximal half of seminal vesicles (clinical target volume, CTV), normal tissue complication probability (NTCP) for the rectum and the percent volume of bladder wall receiving at least 75 Gy were calculated. Results: The patient averaged increase in the planned TCP between plan types 2 and 1 and types 3 and 1 was 9.8% (range 4.9-12.5%) for both, whereas the corresponding increases in treatment TCP were 9.0% (1.3-16%) and 8.1% (-1.3-13.8%). In all patients, plans 2 and 3 (81 Gy) exhibited equal or higher treatment TCP than plan 1 (75.6 Gy). The maximum treatment NTCP for rectum never exceeded the planning constraint and percent volume of bladder wall receiving at least 75 Gy was similar in the planning and treatment scans for all three plans. Conclusion: For plans that deliver a uniform prescribed dose to the planning target volume (PTV) (plan 1), current margins are adequate. In plans that further escalate the dose to part

  6. Thickenings and conformal gravity

    Energy Technology Data Exchange (ETDEWEB)

    LeBrun, C. (State Univ. of New York, Stony Brook, NY (USA). Dept. of Mathematics)

    1991-07-01

    A twistor correspondence is given for complex conformal space-times with vanishing Bach and Eastwood-Dighton tensors; when the Weyl curvature is algebraically general, these equations are precisely the conformal version of Einstein's vacuum equations with cosmological constant. This gives a fully curved version of the linearized correspondence of Baston and Mason (B-M). (orig.).

  7. Conformational stability of calreticulin

    DEFF Research Database (Denmark)

    Jørgensen, C.S.; Trandum, C.; Larsen, N.

    2005-01-01

    The conformational stability of calreticulin was investigated. Apparent unfolding temperatures (T-m) increased from 31 degrees C at pH 5 to 51 degrees C at pH 9, but electrophoretic analysis revealed that calreticulin oligomerized instead of unfolding. Structural analyses showed that the single C......-terminal a-helix was of major importance to the conformational stability of calreticulin....

  8. Clinical variability of target volume description and treatment plans in conformal radiotherapy in muscle invasive bladder cancer

    International Nuclear Information System (INIS)

    Logue, John P; Sharrock, Carole L; Cowan, Richard A.; Read, Graham; Marrs, Julie; Mott, David

    1996-01-01

    Purpose/Objective: The delineation of tumor and the production of a treatment plan to encompass this is the prime step in radiotherapy planning. Conformal radiotherapy is developing rapidly and although plentiful research has addressed the implementation of the radiotherapy prescription, scant attention has been made to the fundamental step of production, by the clinician, of an appropriate target volume. As part of an ongoing randomized trial of conformal radiotherapy, in bladder cancer, we have therefore assessed the interphysician variability of radiologists and radiation oncologists (RO) in assessing Gross Tumor Volume(GTV) (ICRU 50) and the adherence of the radiation oncologists to the study protocol of producing a Planning Target Volume (PTV). Materials and Methods: Four patients with T3 carcinoma of bladder who had been entered into the trial were identified. The clinical details, MR scans and CT scans were made available. Eight RO and 3 dedicated diagnostic oncology radiologists were invited to directly outline the GTV onto CT images on a planning computer consul. The RO in addition created a PTV following the trial protocol of 15mm margin around the GTV. Three RO sub-specialized in Urological radiotherapy; all RO had completed training. Volumes were produced, for each clinician, and comparison of these volumes and their isocenters were analyzed. In addition the margins allowed were measured and compared. Results: There was a maximum variation ratio (largest to smallest volume outlined) of the GTV in the four cases of 1.74 among radiologists and 3.74 among oncologists. There was a significant difference (p=0.01) in mean GTV between RO and the radiologists. The mean GTV of the RO exceeded the radiologists by a factor of 1.29 with a mean difference of 13.4 cm 3 The between observer variance within speciality comprised only 9.9% of the total variance in the data having accounted for case and observers speciality. The variation ratio in PTV among oncologists

  9. A dualistic conformational response to substrate binding in the human serotonin transporter reveals a high affinity state for serotonin

    DEFF Research Database (Denmark)

    Bjerregaard, Henriette; Severinsen, Kasper; Said, Saida

    2015-01-01

    Serotonergic neurotransmission is modulated by the membrane-embedded serotonin transporter (SERT). SERT mediates the reuptake of serotonin into the presynaptic neurons. Conformational changes in SERT occur upon binding of ions and substrate and are crucial for translocation of serotonin across...... the membrane. Our understanding of these conformational changes is mainly based on crystal structures of a bacterial homolog in various conformations, derived homology models of eukaryotic neurotransmitter transporters, and substituted cysteine accessibility method of SERT. However, the dynamic changes...

  10. Emerging paradigm in radiobiology in concept and practices of hypo fractionated conformal radiotherapy

    International Nuclear Information System (INIS)

    Mishra, S.P.; Srivastava, Anoop Kumar; Rastogi, Madhup; Khurana, Rohini; Pawaskar, Asawari

    2016-01-01

    This study has been performed in clinical setting by creating the treatment plan in dynamic conformal arc mode as the treatment delivery technique; with add on collimator APEX system having 56 pairs of 2.5 mm each as treatment unit. Photon beam energy selected for the study was 6 MV. Various number of treatment arcs were applied depending upon the location of the PTV. The PTV was prescribed a total dose of 60 Gy in five fractions

  11. Experimental dosimetry in conformal breast teletherapy compared with the planning system

    International Nuclear Information System (INIS)

    Nogueira, Luciana Batista; Silva, Hugo Leonardo Lemos; Passos Ribeiro de Campos, Tarcísio

    2015-01-01

    The objective of this study was to compare and analyse the absorbed dose profiles from the conformal radiotherapy planning and experimental dosimetry taken in a breast anthropomorphic and anthropometric phantom. Conformal radiotherapy planning was elaborated in the Treatment Planning System (TPS). EBT2 Gafchromic radiochromic films were applied as dosimeters, positioned internally and superficially in the breast phantom. The standard radiation protocol was applied in the breast phantom. The films were digitalised, and their responses were analysed in RGB. The optical densities were processed, reproducing the spatial dose distribution. - Highlights: • Distributions of absorbed doses were generated by the TPS and measured by radiochromic films. • The breast phantom simulated a human breast in position for treatment. • A large portion of the glandular tissue absorbed doses that were equivalent to the radiotherapy planning. • There were regions of hot spots and small areas of under dosage in deeper areas at the lung interface

  12. Self-limiting atomic layer deposition of conformal nanostructured silver films

    International Nuclear Information System (INIS)

    Golrokhi, Zahra; Chalker, Sophia; Sutcliffe, Christopher J.; Potter, Richard J.

    2016-01-01

    Graphical abstract: - Highlights: • We grow metallic silver by direct liquid injection thermal atomic layer deposition. • Highly conformal silver nanoparticle coatings on high aspect ratio surfaces. • An ALD temperature growth window between 123 and 128 °C is established. • ALD cycles provides sub nanometre control of silver growth. • Catalytic dehydrogenation ALD mechanism has been elucidated by in-situ QCM. - Abstract: The controlled deposition of ultra-thin conformal silver nanoparticle films is of interest for applications including anti-microbial surfaces, plasmonics, catalysts and sensors. While numerous techniques can produce silver nanoparticles, few are able to produce highly conformal coatings on high aspect ratio surfaces, together with sub-nanometre control and scalability. Here we develop a self-limiting atomic layer deposition (ALD) process for the deposition of conformal metallic silver nanoparticle films. The films have been deposited using direct liquid injection ALD with ((hexafluoroacetylacetonato)silver(I)(1,5-cyclooctadiene)) and propan-1-ol. An ALD temperature window between 123 and 128 °C is identified and within this range self-limiting growth is confirmed with a mass deposition rate of ∼17.5 ng/cm"2/cycle. The effects of temperature, precursor dose, co-reactant dose and cycle number on the deposition rate and on the properties of the films have been systematically investigated. Under self-limiting conditions, films are metallic silver with a nano-textured surface topography and nanoparticle size is dependent on the number of ALD cycles. The ALD reaction mechanisms have been elucidated using in-situ quartz crystal microbalance (QCM) measurements, showing chemisorption of the silver precursor, followed by heterogeneous catalytic dehydrogenation of the alcohol to form metallic silver and an aldehyde.

  13. Conformity in Christ | Waaijman | Acta Theologica

    African Journals Online (AJOL)

    This essay investigates the notion of conformity in Christ as it is part of a comprehensive, multilayered process of transformation. In the first part it focuses on the process of transformation in creation, re-creation, conformity, love and glory. In the second part it discusses transformation in Christ by looking at conformation and ...

  14. Gauge fixing problem in the conformal QED

    International Nuclear Information System (INIS)

    Ichinose, Shoichi

    1986-01-01

    The gauge fixing problem in the conformal (spinor and scalar) QED is examined. For the analysis, we generalize Dirac's manifestly conformal-covariant formalism. It is shown that the (vector and matter) fields must obey a certain mixed (conformal and gauge) type of transformation law in order to fix the local gauge symmetry preserving the conformal invariance in the Lagrangian. (orig.)

  15. Chain Assembly and Disassembly Processes Differently Affect the Conformational Space of Ubiquitin Chains.

    Science.gov (United States)

    Kniss, Andreas; Schuetz, Denise; Kazemi, Sina; Pluska, Lukas; Spindler, Philipp E; Rogov, Vladimir V; Husnjak, Koraljka; Dikic, Ivan; Güntert, Peter; Sommer, Thomas; Prisner, Thomas F; Dötsch, Volker

    2018-02-06

    Ubiquitination is the most versatile posttranslational modification. The information is encoded by linkage type as well as chain length, which are translated by ubiquitin binding domains into specific signaling events. Chain topology determines the conformational space of a ubiquitin chain and adds an additional regulatory layer to this ubiquitin code. In particular, processes that modify chain length will be affected by chain conformations as they require access to the elongation or cleavage sites. We investigated conformational distributions in the context of chain elongation and disassembly using pulsed electron-electron double resonance spectroscopy in combination with molecular modeling. Analysis of the conformational space of diubiquitin revealed conformational selection or remodeling as mechanisms for chain recognition during elongation or hydrolysis, respectively. Chain elongation to tetraubiquitin increases the sampled conformational space, suggesting that a high intrinsic flexibility of K48-linked chains may contribute to efficient proteasomal degradation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Daily-diary evaluated side-effects of conformal versus conventional prostatic cancer radiotherapy technique

    International Nuclear Information System (INIS)

    Widmark, A.; Fransson, P.; Franzen, L.; Littbrand, B.; Henriksson, R.

    1997-01-01

    Conventional 4-field box radiotherapy technique induces high morbidity for patients with localized prostatic cancer. Using a patient daily diary, the present study compared side-effects after conventional radiotherapy with conformal radiotherapy for prostate cancer. Fifty-eight patients treated with the conventional technique (with or without sucralfate) were compared with 72 patients treated with conformal technique. The patient groups were compared with an age-matched control population. Patients treated with conformal technique were also evaluated regarding acute and late urinary problems. Results showed that patients treated with conformal technique reported significantly fewer side-effects as compared with conventional technique. Patients treated with sucralfate also showed slightly decreased intestinal morbidity in comparison to non-sucralfate group. Acute and late morbidity evaluated by the patients was decreased after conformal radiotherapy as compared with the conventional technique. Sucralfate may be of value if conformal radiotherapy is used for dose escalation in prostatic cancer patients. (orig.)

  17. Very high-energy electron (VHEE) beams in radiation therapy; Treatment plan comparison between VHEE, VMAT, and PPBS.

    Science.gov (United States)

    Schüler, Emil; Eriksson, Kjell; Hynning, Elin; Hancock, Steven L; Hiniker, Susan M; Bazalova-Carter, Magdalena; Wong, Tony; Le, Quynh-Thu; Loo, Billy W; Maxim, Peter G

    2017-06-01

    The aim of this study was to evaluate the performance of very high-energy electron beams (VHEE) in comparison to clinically derived treatment plans generated with volumetric modulated arc therapy (VMAT) and proton pencil beam scanning (PPBS) technology. We developed a custom optimization script that could be applied automatically across modalities to eliminate operator bias during IMRT optimization. Four clinical cases were selected (prostate cancer, lung cancer, pediatric brain tumor, and head and neck cancer (HNC)). The VHEE beams were calculated in the EGSnrc/DOSXYZnrc Monte Carlo code for 100 and 200 MeV beams. Treatment plans with VHEE, VMAT, and PPBS were optimized in a research version of RayStation using an in-house developed script to minimize operator bias between the different techniques. The in-house developed script generated similar or superior plans to the clinically used plans. In the comparisons between the modalities, the integral dose was lowest for the PPBS-generated plans in all cases. For the prostate case, the 200 MeV VHEE plan showed reduced integral dose and reduced organ at risk (OAR) dose compared to the VMAT plan. For all other cases, both the 100 and the 200 MeV VHEE plans were superior to the VMAT plans, and the VHEE plans showed better conformity and lower spinal cord dose in the pediatric brain case and lower brain stem dose in the HNC case when compared to the PPBS plan. The automated optimization developed in this study generated similar or superior plans as compared to the clinically used plan and represents an unbiased approach to compare treatment plans generated for different modalities. In the present study, we also show that VHEE plans are similar or superior to VMAT plans with reduced mean OAR dose and increased target conformity for a variety of clinical cases, and VHEE plans can even achieve reductions in OAR doses compared to PPBS plans for shallow targets. With increased VHEE energy, better conformity and even higher

  18. Transportation Conformity Training and Presentations

    Science.gov (United States)

    EPA's OTAQ has provided multiple conformity training sessions in the past to assist state and local governments in implementing conformity requirements. As training information is prepared for other venues, it will be posted on this page.

  19. Enhanced conformational sampling using enveloping distribution sampling.

    Science.gov (United States)

    Lin, Zhixiong; van Gunsteren, Wilfred F

    2013-10-14

    To lessen the problem of insufficient conformational sampling in biomolecular simulations is still a major challenge in computational biochemistry. In this article, an application of the method of enveloping distribution sampling (EDS) is proposed that addresses this challenge and its sampling efficiency is demonstrated in simulations of a hexa-β-peptide whose conformational equilibrium encompasses two different helical folds, i.e., a right-handed 2.7(10∕12)-helix and a left-handed 3(14)-helix, separated by a high energy barrier. Standard MD simulations of this peptide using the GROMOS 53A6 force field did not reach convergence of the free enthalpy difference between the two helices even after 500 ns of simulation time. The use of soft-core non-bonded interactions in the centre of the peptide did enhance the number of transitions between the helices, but at the same time led to neglect of relevant helical configurations. In the simulations of a two-state EDS reference Hamiltonian that envelops both the physical peptide and the soft-core peptide, sampling of the conformational space of the physical peptide ensures that physically relevant conformations can be visited, and sampling of the conformational space of the soft-core peptide helps to enhance the transitions between the two helices. The EDS simulations sampled many more transitions between the two helices and showed much faster convergence of the relative free enthalpy of the two helices compared with the standard MD simulations with only a slightly larger computational effort to determine optimized EDS parameters. Combined with various methods to smoothen the potential energy surface, the proposed EDS application will be a powerful technique to enhance the sampling efficiency in biomolecular simulations.

  20. Two dimensional infinite conformal symmetry

    International Nuclear Information System (INIS)

    Mohanta, N.N.; Tripathy, K.C.

    1993-01-01

    The invariant discontinuous (discrete) conformal transformation groups, namely the Kleinian and Fuchsian groups Gamma (with an arbitrary signature) of H (the Poincare upper half-plane l) and the unit disc Delta are explicitly constructed from the fundamental domain D. The Riemann surface with signatures of Gamma and conformally invariant automorphic forms (functions) with Peterson scalar product are discussed. The functor, where the category of complex Hilbert spaces spanned by the space of cusp forms constitutes the two dimensional conformal field theory. (Author) 7 refs

  1. Virtual and solution conformations of oligosaccharides

    International Nuclear Information System (INIS)

    Cumming, D.A.; Carver, J.P.

    1987-01-01

    The possibility that observed nuclear Overhauser enhancements and bulk longitudinal relaxation times, parameters measured by 1 H NMR and often employed in determining the preferred solution conformation of biologically important molecules, are the result of averaging over many conformational states is quantitatively evaluated. Of particular interest was to ascertain whether certain 1 H NMR determined conformations are virtual in nature; i.e., the fraction of the population of molecules actually found at any time within the subset of conformational space defined as the solution conformation is vanishingly small. A statistical mechanics approach was utilized to calculate an ensemble average relaxation matrix from which (NOE)'s and (T 1 )'s are calculated. Model glycosidic linkages in four oligosaccharides were studied. The nature of the resultant population distributions is such that 50% of the molecular population is found within 1% of available microstates, while 99% of the molecular population occupies about 10% of the ensemble microstates, a number roughly equal to that sterically allowed. From this analysis the authors conclude that in many cases quantitative interpretation of NMR relaxation data, which attempts to define a single set of allowable torsion angle values consistent with the observed data, will lead to solution conformations that are either virtual or reflect torsion angle values possessed by a minority of the molecular population. Observed values of NMR relaxation data are the result of the complex interdependence of the population distribution and NOE (or T 1 ) surfaces in conformational space. In conformational analyses, NMR data can therefore be used to test different population distributions calculated from empirical potential energy functions

  2. Assessment of conformity and suitability for use of the energy subsystem of interoperable high-speed lines; Konformitaetsbewertung und EG-Pruefverfahren fuer das Teilsystem Energie

    Energy Technology Data Exchange (ETDEWEB)

    Behrends, D. [Steglitzer Damm, Deutschen Bahn, Berlin (Germany); Brodkorb, A.; Matthes, R. [Siemens AG, Erlangen (Germany)

    2003-05-01

    The directive 96/48/EG governs the conformity assessment of conformity of interoperability constituents and of suitability for use of subsystems of the trans-European high-speed rail system. The assessment of the overhead contact line type SICAT H 1.0 and the energy subsystem of the new high-speed line Belgian boundary-Rotterdam-Hoofddop (HSL Zuid) in the Netherlands establish examples for the application of the technical specification for the energy subsystem. (orig.) [German] Die Richtlinie 96/48/EG regelt die Bewertung der Konformitaet von Komponenten und das EG-Pruefverfahren von Teilsystemen des interoperablen transeuropaeischen Hochgeschwindigkeitsbahnsystems. Beispiele fuer diese beiden Vorgaenge sind die Bewertung der Oberleitungsbauart SICAT H 1.0 und die Pruefung der Energieversorgung der Hochgeschwindigkeitsstrecke belgische Grenze-Rotterdam-Hoofddop (HSL Zuid) in den Niederlanden. (orig.)

  3. Conformal Extensions of the Standard Model with Veltman Conditions

    DEFF Research Database (Denmark)

    Antipin, Oleg; Mojaza, Matin; Sannino, Francesco

    2014-01-01

    Using the renormalisation group framework we classify different extensions of the standard model according to their degree of naturality. A new relevant class of perturbative models involving elementary scalars is the one in which the theory simultaneously satisfies the Veltman conditions...... and is conformal at the classical level. We term these extensions perturbative natural conformal (PNC) theories. We show that PNC models are very constrained and thus highly predictive. Among the several PNC examples that we exhibit, we discover a remarkably simple PNC extension of the standard model in which...

  4. Uniform stable conformal convolutional perfectly matched layer for enlarged cell technique conformal finite-difference time-domain method

    International Nuclear Information System (INIS)

    Wang Yue; Wang Jian-Guo; Chen Zai-Gao

    2015-01-01

    Based on conformal construction of physical model in a three-dimensional Cartesian grid, an integral-based conformal convolutional perfectly matched layer (CPML) is given for solving the truncation problem of the open port when the enlarged cell technique conformal finite-difference time-domain (ECT-CFDTD) method is used to simulate the wave propagation inside a perfect electric conductor (PEC) waveguide. The algorithm has the same numerical stability as the ECT-CFDTD method. For the long-time propagation problems of an evanescent wave in a waveguide, several numerical simulations are performed to analyze the reflection error by sweeping the constitutive parameters of the integral-based conformal CPML. Our numerical results show that the integral-based conformal CPML can be used to efficiently truncate the open port of the waveguide. (paper)

  5. Noncommutative geometry and twisted conformal symmetry

    International Nuclear Information System (INIS)

    Matlock, Peter

    2005-01-01

    The twist-deformed conformal algebra is constructed as a Hopf algebra with twisted coproduct. This allows for the definition of conformal symmetry in a noncommutative background geometry. The twisted coproduct is reviewed for the Poincare algebra and the construction is then extended to the full conformal algebra. The case of Moyal-type noncommutativity of the coordinates is considered. It is demonstrated that conformal invariance need not be viewed as incompatible with noncommutative geometry; the noncommutativity of the coordinates appears as a consequence of the twisting, as has been shown in the literature in the case of the twisted Poincare algebra

  6. Superintegrability of d-dimensional conformal blocks

    International Nuclear Information System (INIS)

    Isachenkov, Mikhail

    2016-02-01

    We observe that conformal blocks of scalar 4-point functions in a d-dimensional conformal field theory can mapped to eigenfunctions of a 2-particle hyperbolic Calogero-Sutherland Hamiltonian. The latter describes two coupled Poeschl-Teller particles. Their interaction, whose strength depends smoothly on the dimension d, is known to be superintegrable. Our observation enables us to exploit the rich mathematical literature on Calogero-Sutherland models in deriving various results for conformal field theory. These include an explicit construction of conformal blocks in terms of Heckman-Opdam hypergeometric functions and a remarkable duality that relates the blocks of theories in different dimensions.

  7. Superintegrability of d-dimensional conformal blocks

    Energy Technology Data Exchange (ETDEWEB)

    Isachenkov, Mikhail [Weizmann Institute of Science, Rehovot (Israel). Dept. of Particle Physics and Astronomy; Schomerus, Volker [DESY Theory Group, Hamburg (Germany)

    2016-02-15

    We observe that conformal blocks of scalar 4-point functions in a d-dimensional conformal field theory can mapped to eigenfunctions of a 2-particle hyperbolic Calogero-Sutherland Hamiltonian. The latter describes two coupled Poeschl-Teller particles. Their interaction, whose strength depends smoothly on the dimension d, is known to be superintegrable. Our observation enables us to exploit the rich mathematical literature on Calogero-Sutherland models in deriving various results for conformal field theory. These include an explicit construction of conformal blocks in terms of Heckman-Opdam hypergeometric functions and a remarkable duality that relates the blocks of theories in different dimensions.

  8. Factors related to late GI and GU complications in conformal and conventional radiation treatment of cancer of the prostate

    International Nuclear Information System (INIS)

    Schultheiss, Timothy E.; Lee, W. Robert; Hunt, Margie A.; Hanlon, Alexandra L.; Peter, Ruth S.; Hanks, Gerald E.

    1995-01-01

    Purpose: To assess the factors that predict for late GI and GU morbidity in radiation treatment of the prostate. Materials and Methods: Six hundred sixteen consecutive prostate cancer patients treated between 1985 and 1994 with conformal or conventional techniques were included in the analysis. All patients had at least 3 months followup (median 26 months) and received at least 65 Gy. Late GI morbidity was rectal bleeding (requiring more than 2 procedures) or proctitis. Late GU morbidity was cystitis or stricture. Univariate analysis compared the differences in the incidence of RTOG-EORTC grade 3 and 4 late morbidity by age (<60 versus ≥ 60 years), peracute side effects ≥ grade 1 (during treatment), subacute side effects ≥ grade 1 (0 to 90 days after treatment), irradiated volume parameters, and dose. Multivariate proportional hazards analysis includes these same variables in a model of time to complication. Multivariate logistic regression was used to analyze incidence of peracute and subacute GI and GU side effects by GI and GU comorbidities, performance status, pretreatment procedures (biopsy, TURP, etc.), age, treatment volume parameters, and peracute responses. Results: Peracute GI and GU side effects were noted in 441 and 442 patients, respectively. Subacute GI and GU side effects were noted in 34 and 54 patients, respectively. Subacute GI side effects were highly correlated with subacute GU side effects (p<0.00001). Late morbidities were not correlated with peracute side effects but were correlated with subacute side effects (both GI and GU). Thirteen of the 616 patients expressed grade 3 or 4 GI injuries 3 to 32 months after the end of treatment, with a mean of 13 months. The 6 GU morbidities occurred significantly later (9 - 52 months) with a mean of 33 months. Central axis dose and age less than 60 years were the only independent variables significantly related to the incidence of late GI morbidity on multivariate analysis. Subacute and peracute

  9. Induced quantum conformal gravity

    International Nuclear Information System (INIS)

    Novozhilov, Y.V.; Vassilevich, D.V.

    1988-11-01

    Quantum gravity is considered as induced by matter degrees of freedom and related to the symmetry breakdown in the low energy region of a non-Abelian gauge theory of fundamental fields. An effective action for quantum conformal gravity is derived where both the gravitational constant and conformal kinetic term are positive. Relation with induced classical gravity is established. (author). 15 refs

  10. Local Order in the Unfolded State: Conformational Biases and Nearest Neighbor Interactions

    Directory of Open Access Journals (Sweden)

    Siobhan Toal

    2014-07-01

    Full Text Available The discovery of Intrinsically Disordered Proteins, which contain significant levels of disorder yet perform complex biologically functions, as well as unwanted aggregation, has motivated numerous experimental and theoretical studies aimed at describing residue-level conformational ensembles. Multiple lines of evidence gathered over the last 15 years strongly suggest that amino acids residues display unique and restricted conformational preferences in the unfolded state of peptides and proteins, contrary to one of the basic assumptions of the canonical random coil model. To fully understand residue level order/disorder, however, one has to gain a quantitative, experimentally based picture of conformational distributions and to determine the physical basis underlying residue-level conformational biases. Here, we review the experimental, computational and bioinformatic evidence for conformational preferences of amino acid residues in (mostly short peptides that can be utilized as suitable model systems for unfolded states of peptides and proteins. In this context particular attention is paid to the alleged high polyproline II preference of alanine. We discuss how these conformational propensities may be modulated by peptide solvent interactions and so called nearest-neighbor interactions. The relevance of conformational propensities for the protein folding problem and the understanding of IDPs is briefly discussed.

  11. Poly (3, 4-ethylendioxithiophene) (PEDOT) oxidation: activation energy and conformational energy

    International Nuclear Information System (INIS)

    Otero, T F; Romero, M C

    2008-01-01

    The oxidation kinetics of films of the conducting polymer PEDOT-C1O4 after electrochemical reduction by polarization at increasing cathodic potential was studied by potential steps. The response i/t presents a maximum at intermediate oxidation times. At the maximum the reaction occurs under chemical kinetic control following the expected current variations from the Chemical and Electrochemical Kinetics, when reactant concentrations or temperatures are changed. The obtained activation energy of the oxidation present two ranges as a function of the cathodic potential of prepolarization: constant values after prepolarization at low cathodic potentials and a lineal variation after prepolarization at increasing high cathodic potentials. According with the conformational relaxation model during electrochemical reduction the polymer shrinks, closes and packs the conformational structure. The activation energy for the subsequent oxidation includes two terms: the constant chemical activation energy and the conformational energy required to relax the packed polymeric structure. The conformational energy only appears after prepolarization at more cathodic potentials than the closing potential where more packed conformations were obtained. The conformational activation energy accounts the energetic requirements to relax and unfold the polymeric chains generating the required free volume to lodge balancing counterions; meanwhile the chemical activation energy accounts the energetic requirements for the electrochemical reaction to occur.

  12. Conformal invariance in harmonic superspace

    International Nuclear Information System (INIS)

    Galperin, A.; Ivanov, E.; Ogievetsky, V.; Sokatchev, E.

    1987-01-01

    In the present paper we show how the N = 2 superconformal group is realised in harmonic superspace and examine conformal invariance of N = 2 off-shell theories. We believe that the example of N = O self-dual Yang-Mills equations can serve as an instructive introduction to the subject of harmonic superspace and this is examined. The rigid N = 2 conformal supersymmetry and its local version, i.e. N = 2 conformal supergravity is also discussed. The paper is a contribution to the book commemorating the sixtieth birthday of E.S. Fradkin. (author)

  13. Harmony of spinning conformal blocks

    Energy Technology Data Exchange (ETDEWEB)

    Schomerus, Volker [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group; Sobko, Evgeny [Stockholm Univ. (Sweden); Nordita, Stockholm (Sweden); Isachenkov, Mikhail [Weizmann Institute of Science, Rehovoth (Israel). Dept. of Particle Physics and Astrophysics

    2016-12-07

    Conformal blocks for correlation functions of tensor operators play an increasingly important role for the conformal bootstrap programme. We develop a universal approach to such spinning blocks through the harmonic analysis of certain bundles over a coset of the conformal group. The resulting Casimir equations are given by a matrix version of the Calogero-Sutherland Hamiltonian that describes the scattering of interacting spinning particles in a 1-dimensional external potential. The approach is illustrated in several examples including fermionic seed blocks in 3D CFT where they take a very simple form.

  14. Harmony of spinning conformal blocks

    Energy Technology Data Exchange (ETDEWEB)

    Schomerus, Volker [DESY Hamburg, Theory Group,Notkestraße 85, 22607 Hamburg (Germany); Sobko, Evgeny [Nordita and Stockholm University,Roslagstullsbacken 23, SE-106 91 Stockholm (Sweden); Isachenkov, Mikhail [Department of Particle Physics and Astrophysics, Weizmann Institute of Science,Rehovot 7610001 (Israel)

    2017-03-15

    Conformal blocks for correlation functions of tensor operators play an increasingly important role for the conformal bootstrap programme. We develop a universal approach to such spinning blocks through the harmonic analysis of certain bundles over a coset of the conformal group. The resulting Casimir equations are given by a matrix version of the Calogero-Sutherland Hamiltonian that describes the scattering of interacting spinning particles in a 1-dimensional external potential. The approach is illustrated in several examples including fermionic seed blocks in 3D CFT where they take a very simple form.

  15. Conformational cooling and conformation selective aggregation in dimethyl sulfite isolated in solid rare gases

    Science.gov (United States)

    Borba, Ana; Gómez-Zavaglia, Andrea; Fausto, Rui

    2006-08-01

    Dimethyl sulfite has three conformers of low energy, GG, GT and GG', which have significant populations in the gas phase at room temperature. According to theoretical predictions, the GT and GG' conformers are higher in energy than the GG conformer by 0.83 and 1.18 kJ mol -1, respectively, while the barriers associated with the GG'→GT and GT→GG isomerizations are 1.90 and 9.64 kJ mol -1, respectively. Experimental data obtained for the compound isolated in solid argon, krypton and xenon demonstrated that the GG'→GT energy barrier is low enough to allow an extensive conversion of the GG' form into the GT conformer during deposition of the matrices, the extent of the conversion increasing along the series Arconformers could be trapped in both argon and krypton matrices, but, at a given temperature, the amount of GG' form trapped in krypton is considerably smaller than in argon, while the amount of GT form increases in relation to the most stable GG form. In addition, when xenon is used, no bands due to GG' are observed in the as-deposited spectra ( Tsubstrate≥10 K, the minimum substrate temperature accessible to our experimental set up), indicating that when the best relaxant gas is used the GG'→GT conversion during deposition of the matrix is complete even at 10 K. Annealing of the argon and krypton matrices shows that the increase of the temperature of the matrix first promotes the GG'→GT isomerization, and only at higher temperatures the GT→GG conversion starts to occur, in consonance with the relative energy barriers associated with these two processes. The results also indicate that dimethyl sulfite exhibits conformation selective aggregation, with the most stable form, which has the highest dipole moment, aggregating more easily than the remaining experimentally relevant conformers (GT and GG').

  16. Watching Conformations of Biomolecules: a Microwave Spectroscopy Approach

    Science.gov (United States)

    Lopez, J. C.

    2011-06-01

    The combination of laser ablation with Fourier transform microwave spectroscopy in supersonic jets (LA-MB-FTMW) has made possible the gas-phase study of solid biomolecules with high melting points. In the experiment, solids are efficiently vaporized by a high-energy laser pulse, supersonically expanded into a evacuated Fabry-Perot cavity and characterised by their rotational spectra. Recent improvements such as the use of picosecond pulse lasers, new ablation nozzles and the extension of the range of the spectrometers to low frequecy have notably increased the sensitivity of our experimental setup. To date different α-, β- and γ-amino acids have been studied using this technique, making possible the characterization of their preferred conformations and gaining insight in the role of intramolecular interactions. Even in conformationally challenging systems the different rotamers of such biomolecules can be identified by rotational spectroscopy as can be illustrated by the assignment of six low-energy conformers in cysteine and aspartic acid, seven in serine and threonine,^a and nine in γ-amino butyric acid (GABA). In all cases the low-energy conformers have been conclusive identified from their experimental rotational and 14N quadrupole coupling constants. The spectra of neurotransmitters and of the nucleic acid bases uracil, thymine, cytosine and guanine have also been studied and their preferred conformers or tautomeric forms determined. The complexes between amino acids and nucleic acid bases with water have also been investigated to obtain information on the possible changes induced in the conformational or tautomeric preferences by the addition of solvent molecules. J. L. Alonso, C. Pérez, M. E. Sanz, J. C. López, S. Blanco, Phys. Chem. Chem. Phys. 11, 617-627 (2009) and references therein M. E. Sanz, J. C. López, J. L. Alonso, Phys. Chem. Chem. Phys., 12, 3573-3578 (2010) S. Blanco, J. C. López, S. Mata and J. L. Alonso, Angew. Chem. Int. Ed. 49, 9187

  17. Conformal hyperbolicity of Lorentzian warped products

    International Nuclear Information System (INIS)

    Markowitz, M.J.

    1982-01-01

    A space-time M is said to be conformally hyperbolic if the intrinsic conformal Lorentz pseudodistance dsub(M) is a true distance. In this paper criteria are derived which insure the conformal hyperbolicity of certain space-times which are generalizations of the Robertson-Walker spaces. Then dsub(M) is determined explicitly for Einstein-de Sitter space, and important cosmological model. (author)

  18. Conformal hyperbolicity of Lorentzian warped products

    Energy Technology Data Exchange (ETDEWEB)

    Markowitz, M.J. (Chicago Univ., IL (USA). Dept. of Mathematics)

    1982-12-01

    A space-time M is said to be conformally hyperbolic if the intrinsic conformal Lorentz pseudodistance dsub(M) is a true distance. In this paper criteria are derived which insure the conformal hyperbolicity of certain space-times which are generalizations of the Robertson-Walker spaces. Then dsub(M) is determined explicitly for Einstein-de Sitter space, and important cosmological model.

  19. Non-linear realizations of conformal symmetry and effective field theory for the pseudo-conformal universe

    International Nuclear Information System (INIS)

    Hinterbichler, Kurt; Joyce, Austin; Khoury, Justin

    2012-01-01

    The pseudo-conformal scenario is an alternative to inflation in which the early universe is described by an approximate conformal field theory on flat, Minkowski space. Some fields acquire a time-dependent expectation value, which breaks the flat space so(4,2) conformal algebra to its so(4,1) de Sitter subalgebra. As a result, weight-0 fields acquire a scale invariant spectrum of perturbations. The scenario is very general, and its essential features are determined by the symmetry breaking pattern, irrespective of the details of the underlying microphysics. In this paper, we apply the well-known coset technique to derive the most general effective lagrangian describing the Goldstone field and matter fields, consistent with the assumed symmetries. The resulting action captures the low energy dynamics of any pseudo-conformal realization, including the U(1)-invariant quartic model and the Galilean Genesis scenario. We also derive this lagrangian using an alternative method of curvature invariants, consisting of writing down geometric scalars in terms of the conformal mode. Using this general effective action, we compute the two-point function for the Goldstone and a fiducial weight-0 field, as well as some sample three-point functions involving these fields

  20. General Conformity

    Science.gov (United States)

    The General Conformity requirements ensure that the actions taken by federal agencies in nonattainment and maintenance areas do not interfere with a state’s plans to meet national standards for air quality.

  1. NMR and computer modelling conformational study of N-benzyl, N-n-propyl (2-methyl-3-nitrophenyl)acetamide

    International Nuclear Information System (INIS)

    Nicolle, E.; Benoit-Guyod, M.; Namil, A.; Cussac, M.; Leclerc, G.; Maldivi, P.

    1995-01-01

    The conformation of N-benzyl-N-n-propyl (2-methyl-3-nitrophenyl) acetamide 1 in dimethyl sulfoxide (DMSO-d 6 ) or chloroform (CDCL 3 ) solution was studied using 1 H and 13 CNMR analysis. In solution, 1 existed as two distinct Z and E isomers, which could not be separated at laboratory temperature. Both conformations were in equivalent proportions in chloroform whereas in a polar solvent (DMSO), the conformation Z was more usual with the aromatic rings in a transposition. Major and minor rotation isomers were assigned form the '1H and 13 C NMR chemical shifts determined at 293 K. Separate treatment of signals displayed by two different methylene groups gave comparable activation parameters (ΔG ∼ 16 kcal/mol). Conformational analysis and measurement of the rotational barrier between the E and Z conformers by molecular modeling (Sybyl program) were performed. (authors). 14 refs., 8 figs

  2. Implementation of intensity-modulated conformational radiotherapy (IMRT) for the treatment of cervical cancers at the Alexis-Vautrin Centre; Implementation de la radiotherapie conformationnelle avec modulation d'intensite (RCMI) pour le traitement des cancers du col uterin au centre Alexis-Vautrin

    Energy Technology Data Exchange (ETDEWEB)

    Renard-Oldrini, S.; Brunaud, C.; Marchesi, V.; Tournier-Rangeard, L.; Peiffert, D. [Centre Alexis-Vautrin, 54 - Nancy (France)

    2010-10-15

    The authors discuss the comparison of the treatment plans of eleven patients treated either by conformational irradiation for seven of them, or by intensity-modulated conformational irradiation (IMRT) for four of them. The IMRT results in a good target volume coverage, can better protect the intestine than the conventional irradiation, and therefore is very promising, notably in terms of digestive toxicity. Short communication

  3. Conformity and Internalisation in a Participative Decision Making Process

    International Nuclear Information System (INIS)

    Bombaerts, Gunter

    2003-01-01

    This paper reflects upon the stretching concept of the RISCOM model. We agree with the Habermassian point of departure that a competent speaker makes validity claims on truth, legitimacy and authenticity and partially with the Dialogue Project's conclusions that opening the black box of science is not possible in a decision making process (DMP) on a highly technical issue. Accordingly, we see an important role for a regulator to stretch the implementer, i.e. balance commercial and guardian ethics in the DMP. However, some caution is needed. Conformity studies indicate the large influence of group norms on individuals. When individuals lack personal reference frames of a particular issue they are prone to conform. The more values are shared, the more group members are convinced of the correctness. And social psychology shows more. In studies on persuasion, a difference between compliance and internalisation is made. Compliance is attained from rewards and coercive sources of power, whereas internalisation originates from expertise, legitimacy and credibility. Because of the shift to legitimacy and authenticity in the DMP, alignment of the norms and internalisation of discussed values becomes more apparent in the RISCOM participation model. Conformity reactions and possible internalisation are normal aspect of human interaction and not necessarily a negative aspect of public involvement. But keeping the importance of conformity in mind, a few consequences can be mentioned with regard to the relation implementer-regulator, the non-participation majority, and non-participating critics. The new role of the regulator and the involved public in the RISCOM mode] cannot absolutely avoid the risks due to conformity, it can only decrease the conformity influence

  4. Epigenetic dominance of prion conformers.

    Directory of Open Access Journals (Sweden)

    Eri Saijo

    2013-10-01

    Full Text Available Although they share certain biological properties with nucleic acid based infectious agents, prions, the causative agents of invariably fatal, transmissible neurodegenerative disorders such as bovine spongiform encephalopathy, sheep scrapie, and human Creutzfeldt Jakob disease, propagate by conformational templating of host encoded proteins. Once thought to be unique to these diseases, this mechanism is now recognized as a ubiquitous means of information transfer in biological systems, including other protein misfolding disorders such as those causing Alzheimer's and Parkinson's diseases. To address the poorly understood mechanism by which host prion protein (PrP primary structures interact with distinct prion conformations to influence pathogenesis, we produced transgenic (Tg mice expressing different sheep scrapie susceptibility alleles, varying only at a single amino acid at PrP residue 136. Tg mice expressing ovine PrP with alanine (A at (OvPrP-A136 infected with SSBP/1 scrapie prions propagated a relatively stable (S prion conformation, which accumulated as punctate aggregates in the brain, and produced prolonged incubation times. In contrast, Tg mice expressing OvPrP with valine (V at 136 (OvPrP-V136 infected with the same prions developed disease rapidly, and the converted prion was comprised of an unstable (U, diffusely distributed conformer. Infected Tg mice co-expressing both alleles manifested properties consistent with the U conformer, suggesting a dominant effect resulting from exclusive conversion of OvPrP-V136 but not OvPrP-A136. Surprisingly, however, studies with monoclonal antibody (mAb PRC5, which discriminates OvPrP-A136 from OvPrP-V136, revealed substantial conversion of OvPrP-A136. Moreover, the resulting OvPrP-A136 prion acquired the characteristics of the U conformer. These results, substantiated by in vitro analyses, indicated that co-expression of OvPrP-V136 altered the conversion potential of OvPrP-A136 from the S to

  5. Conformational Heterogeneity in Antibody-Protein Antigen Recognition IMPLICATIONS FOR HIGH AFFINITY PROTEIN COMPLEX FORMATION

    Czech Academy of Sciences Publication Activity Database

    Addis, P. W.; Hall, c. J.; Bruton, S.; Veverka, Václav; Wilkinson, I. C.; Muskett, F. W.; Renshaw, P. S.; Prosser, C. E.; Carrington, B.; Lawson, A. D. G.; Griffin, R.; Taylor, R. J.; Waters, L. C.; Henry, A. J.; Carr, M. D.

    2014-01-01

    Roč. 289, č. 10 (2014), s. 7200-7210 ISSN 0021-9258 Institutional support: RVO:61388963 Keywords : NMR * antibody * protein-protein interaction * protein conformation Subject RIV: CE - Biochemistry Impact factor: 4.573, year: 2014

  6. Conformal Dimensions via Large Charge Expansion.

    Science.gov (United States)

    Banerjee, Debasish; Chandrasekharan, Shailesh; Orlando, Domenico

    2018-02-09

    We construct an efficient Monte Carlo algorithm that overcomes the severe signal-to-noise ratio problems and helps us to accurately compute the conformal dimensions of large-Q fields at the Wilson-Fisher fixed point in the O(2) universality class. Using it, we verify a recent proposal that conformal dimensions of strongly coupled conformal field theories with a global U(1) charge can be obtained via a series expansion in the inverse charge 1/Q. We find that the conformal dimensions of the lowest operator with a fixed charge Q are almost entirely determined by the first few terms in the series.

  7. Some Progress in Conformal Geometry

    Directory of Open Access Journals (Sweden)

    Sun-Yung A. Chang

    2007-12-01

    Full Text Available This is a survey paper of our current research on the theory of partial differential equations in conformal geometry. Our intention is to describe some of our current works in a rather brief and expository fashion. We are not giving a comprehensive survey on the subject and references cited here are not intended to be complete. We introduce a bubble tree structure to study the degeneration of a class of Yamabe metrics on Bach flat manifolds satisfying some global conformal bounds on compact manifolds of dimension 4. As applications, we establish a gap theorem, a finiteness theorem for diffeomorphism type for this class, and diameter bound of the $sigma_2$-metrics in a class of conformal 4-manifolds. For conformally compact Einstein metrics we introduce an eigenfunction compactification. As a consequence we obtain some topological constraints in terms of renormalized volumes.

  8. MAESTRO: Methods and Advanced Equipment for Simulation and Treatment in Radio-Oncology

    Science.gov (United States)

    Barthe, Jean; Hugon, Régis; Nicolai, Jean Philippe

    2007-12-01

    The integrated project MAESTRO (Methods and Advanced Equipment for Simulation and Treatment in Radio-Oncology) under contract with the European Commission in life sciences FP6 (LSHC-CT-2004-503564), concerns innovative research to develop and validate in clinical conditions, advanced methods and equipment needed in cancer treatment for new modalities in high-conformal external radiotherapy using electrons, photons and protons beams of high energy.

  9. Algebraic conformal field theory

    International Nuclear Information System (INIS)

    Fuchs, J.; Nationaal Inst. voor Kernfysica en Hoge-Energiefysica

    1991-11-01

    Many conformal field theory features are special versions of structures which are present in arbitrary 2-dimensional quantum field theories. So it makes sense to describe 2-dimensional conformal field theories in context of algebraic theory of superselection sectors. While most of the results of the algebraic theory are rather abstract, conformal field theories offer the possibility to work out many formulae explicitly. In particular, one can construct the full algebra A-bar of global observables and the endomorphisms of A-bar which represent the superselection sectors. Some explicit results are presented for the level 1 so(N) WZW theories; the algebra A-bar is found to be the enveloping algebra of a Lie algebra L-bar which is an extension of the chiral symmetry algebra of the WZW theory. (author). 21 refs., 6 figs

  10. Treatment planning for SBRT using automated field delivery: A case study

    International Nuclear Information System (INIS)

    Ritter, Timothy A.; Owen, Dawn; Brooks, Cassandra M.; Stenmark, Matthew H.

    2015-01-01

    Stereotactic body radiation therapy (SBRT) treatment planning and delivery can be accomplished using a variety of techniques that achieve highly conformal dose distributions. Herein, we describe a template-based automated treatment field approach that enables rapid delivery of more than 20 coplanar fields. A case study is presented to demonstrate how modest adaptations to traditional SBRT planning can be implemented to take clinical advantage of this technology. Treatment was planned for a left-sided lung lesion adjacent to the chest wall using 25 coplanar treatment fields spaced at 11° intervals. The plan spares the contralateral lung and is in compliance with the conformality standards set forth in Radiation Therapy and Oncology Group protocol 0915, and the dose tolerances found in the report of the American Association of Physicists in Medicine Task Group 101. Using a standard template, treatment planning was accomplished in less than 20 minutes, and each 10 Gy fraction was delivered in approximately 5.4 minutes. For those centers equipped with linear accelerators capable of automated treatment field delivery, the use of more than 20 coplanar fields is a viable SBRT planning approach and yields excellent conformality and quality combined with rapid planning and treatment delivery. Although the case study discusses a laterally located lung lesion, this technique can be applied to centrally located tumors with similar results

  11. 47 CFR 68.320 - Supplier's Declaration of Conformity.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Supplier's Declaration of Conformity. 68.320... Approval § 68.320 Supplier's Declaration of Conformity. (a) Supplier's Declaration of Conformity is a... Supplier's Declaration of Conformity attaches to all items subsequently marketed by the responsible party...

  12. Dynamic Optimization and Conformity in Health Behavior and Life Enjoyment over the Life Cycle

    Directory of Open Access Journals (Sweden)

    Hernan Daniel Bejarano

    2015-06-01

    Full Text Available This article examines individual and social influences on investments in health and enjoyment from immediate consumption. Our lab experiment mimics the problem of health investment over a lifetime (Grossman 1972a, 1972b. Incentives to find the appropriate expenditures on life enjoyment and health are given by making in each period come period a function of previous health investments. In order to model social effects in the experiment, we randomly assigned individuals to chat/observation groups. Groups were permitted to freely chat between repeated lifetimes. Two treatments were employed: In the Independent-rewards treatment, an individual’s rewards from investments in life enjoyment depend only on his choice and in the Interdependent-rewards treatment; rewards not only depend on an individual’s choices but also on their similarity to the choices of the others in their group, generating a premium on conformity. The principal hypothesis is that gains from conformity increase variance in health behavior among groups and can lead to suboptimal performance. We tested three predictions and each was supported by the data: the Interdependent-rewards treatment 1 decreased within-group variance, 2 increased between-group variance, and 3 increased the likelihood of behavior far from the optimum with respect to the dynamic problem. We also test and find support for a series of subsidiary hypotheses. We found: 4 Subjects engaged in helpful chat in both treatments; 5 there was significant heterogeneity among both subjects and groups in chat frequencies; and 6 chat was most common early in the experiment, and 7 the interdependent rewards treatment increased strategic chat frequency. Incentives for conformity appear to promote prosocial behavior, but also increase variance among groups, leading to convergence on suboptimal strategies for some groups. We discuss these results in light of the growing literature focusing on social networks and health outcomes.

  13. Gastro-intestinal and genito-urinary morbidity after 3D conformal radiotherapy of prostate cancer: observations of a randomized trial

    International Nuclear Information System (INIS)

    Koper, Peter C.; Jansen, Peter; Putten, Wim van; Os, Marjolein van; Wijnmaalen, Arend J.; Lebesque, Joos V.; Levendag, Peter C.

    2004-01-01

    Background and purpose: The late morbidity of a randomized study was analyzed after a follow up of 2 years. The difference in intestinal morbidity was analyzed as a function of the treatment arm and dose volume parameters. The correlation with acute toxicity and (pre-existing) bowel complaints was investigated. Patients and methods: 266 T1-4N0M0 prostate cancer patients were randomized for conventional (open fields) and 3D conformal radiotherapy using beams eye view blocked fields with the same dose (66 Gy) and gross target volume-planning target volume margin (15 mm). Apart from the RTOG toxicity scoring system a patient self-assessment questionnaire was used to obtain detailed information on morbidity. Results: At 2 years there is only a trend for less rectal toxicity (grade≥1) in favor of the conformal radiotherapy (grade 1, 47 versus 40% and grade 2, 10 versus 7% for conventional and conformal radiotherapy, respectively (P=0.1). A significant relation was found between late rectal toxicity (grade≥1) and the volume of the anus and rectum exposed to≥90% tumor dose (TD). A highly significant relationship is observed between acute rectum and anal toxicity and late rectal toxicity. The patient self-assessment questionnaire analysis revealed that patients are most bothered by compliance related symptoms like urgency, soiling and fecal loss. In a multivariate analysis, all other variables loose significance, when anal volume exposed to≥90% TD and pre-treatment defaecation frequency are accounted for. Late anal toxicity is low and related only to acute anal toxicity. Late bladder toxicity is related solely to pre-treatment frequency and overall urological symptoms. The incidence of grade 2 toxicity increases with a factor 2.5-4 when (stool or urine) frequency is unfavorable at the start of treatment. Conclusions: Conformal radiotherapy at the dose level of 66 Gy does not significantly decrease the incidence of rectal, anal and bladder toxicity compared to

  14. Conformational effects in photoelectron circular dichroism

    Science.gov (United States)

    Turchini, S.

    2017-12-01

    Photoelectron circular dichroism (PECD) is a novel type of spectroscopy, which presents surprising sensitivity to conformational effects in chiral systems. While classical photoelectron spectroscopy mainly responds to conformational effects in terms of energy level shifts, PECD provides a rich and detailed response to tiny changes in electronic and structural properties by means of the intensity dispersion of the circular dichroism as a function of photoelectron kinetic energy. In this work, the basics of PECD will be outlined, emphasizing the role of interference from the l,l+/- 1 outgoing partial wave of the photoelectron in the PECD transition matrix element, which is responsible for the extreme sensitivity to conformational effects. Examples using molecular systems and interfaces will shed light on the powerful application of PECD to classical conformational effects such as group substitution, isomerism, conformer population and clustering. Moreover, the PECD results will be reported in challenging new fields where conformations play a key role, such as vibrational effects, transient chirality and time- resolved experiments. To date, PECD has mostly been based on synchrotron radiation facilities, but it also has a future as a table-top lab experiment by means of multiphoton ionization. An important application of PECD as an analytical tool will be reported. The aim of this review is to illustrate that in PECD, the presence of conformational effects is essential for understanding a wide range of effects from a new perspective, making it different from classical spectroscopy.

  15. Quality assurance for high dose rate brachytherapy treatment planning optimization: using a simple optimization to verify a complex optimization

    International Nuclear Information System (INIS)

    Deufel, Christopher L; Furutani, Keith M

    2014-01-01

    As dose optimization for high dose rate brachytherapy becomes more complex, it becomes increasingly important to have a means of verifying that optimization results are reasonable. A method is presented for using a simple optimization as quality assurance for the more complex optimization algorithms typically found in commercial brachytherapy treatment planning systems. Quality assurance tests may be performed during commissioning, at regular intervals, and/or on a patient specific basis. A simple optimization method is provided that optimizes conformal target coverage using an exact, variance-based, algebraic approach. Metrics such as dose volume histogram, conformality index, and total reference air kerma agree closely between simple and complex optimizations for breast, cervix, prostate, and planar applicators. The simple optimization is shown to be a sensitive measure for identifying failures in a commercial treatment planning system that are possibly due to operator error or weaknesses in planning system optimization algorithms. Results from the simple optimization are surprisingly similar to the results from a more complex, commercial optimization for several clinical applications. This suggests that there are only modest gains to be made from making brachytherapy optimization more complex. The improvements expected from sophisticated linear optimizations, such as PARETO methods, will largely be in making systems more user friendly and efficient, rather than in finding dramatically better source strength distributions. (paper)

  16. Higher-derivative generalization of conformal mechanics

    Science.gov (United States)

    Baranovsky, Oleg

    2017-08-01

    Higher-derivative analogs of multidimensional conformal particle and many-body conformal mechanics are constructed. Their Newton-Hooke counterparts are derived by applying appropriate coordinate transformations.

  17. Gluon amplitudes as 2 d conformal correlators

    Science.gov (United States)

    Pasterski, Sabrina; Shao, Shu-Heng; Strominger, Andrew

    2017-10-01

    Recently, spin-one wave functions in four dimensions that are conformal primaries of the Lorentz group S L (2 ,C ) were constructed. We compute low-point, tree-level gluon scattering amplitudes in the space of these conformal primary wave functions. The answers have the same conformal covariance as correlators of spin-one primaries in a 2 d CFT. The Britto-Cachazo-Feng-Witten (BCFW) recursion relation between three- and four-point gluon amplitudes is recast into this conformal basis.

  18. Spectral Elements Analysis for Viscoelastic Fluids at High Weissenberg Number Using Logarithmic conformation Tensor Model

    Science.gov (United States)

    Jafari, Azadeh; Deville, Michel O.; Fiétier, Nicolas

    2008-09-01

    This study discusses the capability of the constitutive laws for the matrix logarithm of the conformation tensor (LCT model) within the framework of the spectral elements method. The high Weissenberg number problems (HWNP) usually produce a lack of convergence of the numerical algorithms. Even though the question whether the HWNP is a purely numerical problem or rather a breakdown of the constitutive law of the model has remained somewhat of a mystery, it has been recognized that the selection of an appropriate constitutive equation constitutes a very crucial step although implementing a suitable numerical technique is still important for successful discrete modeling of non-Newtonian flows. The LCT model formulation of the viscoelastic equations originally suggested by Fattal and Kupferman is applied for 2-dimensional (2D) FENE-CR model. The Planar Poiseuille flow is considered as a benchmark problem to test this representation at high Weissenberg number. The numerical results are compared with numerical solution of the standard constitutive equation.

  19. Multichannel conformal blocks for scattering amplitudes

    Science.gov (United States)

    Belitsky, A. V.

    2018-05-01

    By performing resummation of small fermion-antifermion pairs within the pentagon form factor program to scattering amplitudes in planar N = 4 superYang-Mills theory, we construct multichannel conformal blocks within the flux-tube picture for N-sided NMHV polygons. This procedure is equivalent to summation of descendants of conformal primaries in the OPE framework. The resulting conformal partial waves are determined by multivariable hypergeometric series of Lauricella-Saran type.

  20. Conformation Generation: The State of the Art.

    Science.gov (United States)

    Hawkins, Paul C D

    2017-08-28

    The generation of conformations for small molecules is a problem of continuing interest in cheminformatics and computational drug discovery. This review will present an overview of methods used to sample conformational space, focusing on those methods designed for organic molecules commonly of interest in drug discovery. Different approaches to both the sampling of conformational space and the scoring of conformational stability will be compared and contrasted, with an emphasis on those methods suitable for conformer sampling of large numbers of drug-like molecules. Particular attention will be devoted to the appropriate utilization of information from experimental solid-state structures in validating and evaluating the performance of these tools. The review will conclude with some areas worthy of further investigation.

  1. The pseudo-conformal universe: scale invariance from spontaneous breaking of conformal symmetry

    International Nuclear Information System (INIS)

    Hinterbichler, Kurt; Khoury, Justin

    2012-01-01

    We present a novel theory of the very early universe which addresses the traditional horizon and flatness problems of big bang cosmology and predicts a scale invariant spectrum of perturbations. Unlike inflation, this scenario requires no exponential accelerated expansion of space-time. Instead, the early universe is described by a conformal field theory minimally coupled to gravity. The conformal fields develop a time-dependent expectation value which breaks the flat space so(4,2) conformal symmetry down to so(4,1), the symmetries of de Sitter, giving perturbations a scale invariant spectrum. The solution is an attractor, at least in the case of a single time-dependent field. Meanwhile, the metric background remains approximately flat but slowly contracts, which makes the universe increasingly flat, homogeneous and isotropic, akin to the smoothing mechanism of ekpyrotic cosmology. Our scenario is very general, requiring only a conformal field theory capable of developing the appropriate time-dependent expectation values, and encompasses existing incarnations of this idea, specifically the U(1) model of Rubakov and the Galileon Genesis scenario. Its essential features depend only on the symmetry breaking pattern and not on the details of the underlying lagrangian. It makes generic observational predictions that make it potentially distinguishable from standard inflation, in particular significant non-gaussianities and the absence of primordial gravitational waves

  2. Arbitrary spin conformal fields in (A)dS

    International Nuclear Information System (INIS)

    Metsaev, R.R.

    2014-01-01

    Totally symmetric arbitrary spin conformal fields in (A)dS space of even dimension greater than or equal to four are studied. Ordinary-derivative and gauge invariant Lagrangian formulation for such fields is obtained. Gauge symmetries are realized by using auxiliary fields and Stueckelberg fields. We demonstrate that Lagrangian of conformal field is decomposed into a sum of gauge invariant Lagrangians for massless, partial-massless, and massive fields. We obtain a mass spectrum of the partial-massless and massive fields and confirm the conjecture about the mass spectrum made in the earlier literature. In contrast to conformal fields in flat space, the kinetic terms of conformal fields in (A)dS space turn out to be diagonal with respect to fields entering the Lagrangian. Explicit form of conformal transformation which maps conformal field in flat space to conformal field in (A)dS space is obtained. Covariant Lorentz-like and de-Donder like gauge conditions leading to simple gauge-fixed Lagrangian of conformal fields are proposed. Using such gauge-fixed Lagrangian, which is invariant under global BRST transformations, we explain how the partition function of conformal field is obtained in the framework of our approach

  3. Inverse bootstrapping conformal field theories

    Science.gov (United States)

    Li, Wenliang

    2018-01-01

    We propose a novel approach to study conformal field theories (CFTs) in general dimensions. In the conformal bootstrap program, one usually searches for consistent CFT data that satisfy crossing symmetry. In the new method, we reverse the logic and interpret manifestly crossing-symmetric functions as generating functions of conformal data. Physical CFTs can be obtained by scanning the space of crossing-symmetric functions. By truncating the fusion rules, we are able to concentrate on the low-lying operators and derive some approximate relations for their conformal data. It turns out that the free scalar theory, the 2d minimal model CFTs, the ϕ 4 Wilson-Fisher CFT, the Lee-Yang CFTs and the Ising CFTs are consistent with the universal relations from the minimal fusion rule ϕ 1 × ϕ 1 = I + ϕ 2 + T , where ϕ 1 , ϕ 2 are scalar operators, I is the identity operator and T is the stress tensor.

  4. On functional representations of the conformal algebra

    Energy Technology Data Exchange (ETDEWEB)

    Rosten, Oliver J.

    2017-07-15

    Starting with conformally covariant correlation functions, a sequence of functional representations of the conformal algebra is constructed. A key step is the introduction of representations which involve an auxiliary functional. It is observed that these functionals are not arbitrary but rather must satisfy a pair of consistency equations corresponding to dilatation and special conformal invariance. In a particular representation, the former corresponds to the canonical form of the exact renormalization group equation specialized to a fixed point whereas the latter is new. This provides a concrete understanding of how conformal invariance is realized as a property of the Wilsonian effective action and the relationship to action-free formulations of conformal field theory. Subsequently, it is argued that the conformal Ward Identities serve to define a particular representation of the energy-momentum tensor. Consistency of this construction implies Polchinski's conditions for improving the energy-momentum tensor of a conformal field theory such that it is traceless. In the Wilsonian approach, the exactly marginal, redundant field which generates lines of physically equivalent fixed points is identified as the trace of the energy-momentum tensor. (orig.)

  5. Maximizing gain in high-throughput screening using conformal prediction.

    Science.gov (United States)

    Svensson, Fredrik; Afzal, Avid M; Norinder, Ulf; Bender, Andreas

    2018-02-21

    Iterative screening has emerged as a promising approach to increase the efficiency of screening campaigns compared to traditional high throughput approaches. By learning from a subset of the compound library, inferences on what compounds to screen next can be made by predictive models, resulting in more efficient screening. One way to evaluate screening is to consider the cost of screening compared to the gain associated with finding an active compound. In this work, we introduce a conformal predictor coupled with a gain-cost function with the aim to maximise gain in iterative screening. Using this setup we were able to show that by evaluating the predictions on the training data, very accurate predictions on what settings will produce the highest gain on the test data can be made. We evaluate the approach on 12 bioactivity datasets from PubChem training the models using 20% of the data. Depending on the settings of the gain-cost function, the settings generating the maximum gain were accurately identified in 8-10 out of the 12 datasets. Broadly, our approach can predict what strategy generates the highest gain based on the results of the cost-gain evaluation: to screen the compounds predicted to be active, to screen all the remaining data, or not to screen any additional compounds. When the algorithm indicates that the predicted active compounds should be screened, our approach also indicates what confidence level to apply in order to maximize gain. Hence, our approach facilitates decision-making and allocation of the resources where they deliver the most value by indicating in advance the likely outcome of a screening campaign.

  6. Hidden conformal symmetry of a rotating black hole with four charges

    International Nuclear Information System (INIS)

    Shao Kainan; Zhang Zhibai

    2011-01-01

    Kerr/CFT correspondence exhibits many remarkable connections between the near-horizon Kerr black hole and a conformal field theory (CFT). Recently, Castro, Maloney, and Strominger showed that a hidden conformal symmetry exists in the solution space of a Kerr black hole. In this paper we investigate a rotating black hole with four independent U(1) charges derived from string theory which is known as the four-dimensional Cvetic-Youm solution, and we prove that the same hidden conformal symmetry also holds. We obtain the exact black hole entropy using the temperatures derived. The entropy and absorption cross section agree with the previous results [M. Cvetic and F. Larsen, Nucl. Phys. B506, 107 (1997).] and [M. Cvetic and F. Larsen, J. High Energy Phys. 09 (2009) 088.]. In addition, we clarify a previous explanation on the temperatures of the Cvetic-Youm solution's dual CFT. This work provides more robust derivation of the hidden conformal symmetry of Kerr-like black holes and as well as Kerr/CFT correspondence.

  7. Cross-protection in Neisseria meningitidis serogroups Y and W polysaccharides: A comparative conformational analysis.

    Science.gov (United States)

    Kuttel, Michelle M; Timol, Zaheer; Ravenscroft, Neil

    2017-06-29

    The capsular polysaccharide is the main virulence factor in meningococcus. The capsular polysaccharides for meningococcal serogroups Y and W are almost identical polymers of hexose-sialic acid, suggesting the possibility of cross-protection between group Y and W vaccines. However, early studies indicated that they elicit different levels of cross-protection. Here we explore the conformations of the meningococcal Y and W polysaccharides with molecular dynamics simulations of three repeating unit oligosaccharide strands. We find differences in Y and W antigen conformation: the Y polysaccharide has a single dominant conformation, whereas W exhibits a family of conformations including the Y conformation. This result is supported by our NMR NOESY analysis, which indicates key close contacts for W that are not present in Y. These conformational differences provide an explanation for the different levels of cross-protection measured for the Y and W monovalent vaccines and the high group W responses observed in HibMenCY-TT vaccinees. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Vibration atomic layer deposition for conformal nanoparticle coating

    Energy Technology Data Exchange (ETDEWEB)

    Park, Suk Won; Woo Kim, Jun; Jong Choi, Hyung; Hyung Shim, Joon, E-mail: shimm@korea.ac.kr [School of Mechanical Engineering, Korea University, Seoul 136-701 (Korea, Republic of)

    2014-01-15

    A vibration atomic layer deposition reactor was developed for fabricating a conformal thin-film coating on nanosize particles. In this study, atomic layer deposition of 10–15-nm-thick Al{sub 2}O{sub 3} films was conducted on a high-surface-area acetylene black powder with particle diameters of 200–250 nm. Intense vibration during the deposition resulted in the effective separation of particles, overcoming the interparticle agglomeration force and enabling effective diffusion of the precursor into the powder chunk; this phenomenon led to the formation of a conformal film coating on the nanopowder particles. It was also confirmed that the atomic layer deposition Al{sub 2}O{sub 3} films initially grew on the high-surface-area acetylene black powder particles as discrete islands, presumably because chemisorption of the precursor and water occurred only on a few sites on the high-surface-area acetylene black powder surface. Relatively sluggish growth of the films during the initial atomic layer deposition cycles was identified from composition analysis.

  9. 40 CFR 89.105 - Certificate of conformity.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Certificate of conformity. 89.105... and Certification Provisions § 89.105 Certificate of conformity. Every manufacturer of a new nonroad compression-ignition engine must obtain a certificate of conformity covering the engine family, as described...

  10. Controlling Chain Conformations of High-k Fluoropolymer Dielectrics to Enhance Charge Mobilities in Rubrene Single-Crystal Field-Effect Transistors.

    Science.gov (United States)

    Adhikari, Jwala M; Gadinski, Matthew R; Li, Qi; Sun, Kaige G; Reyes-Martinez, Marcos A; Iagodkine, Elissei; Briseno, Alejandro L; Jackson, Thomas N; Wang, Qing; Gomez, Enrique D

    2016-12-01

    A novel photopatternable high-k fluoropolymer, poly(vinylidene fluoride-bromotrifluoroethylene) P(VDF-BTFE), with a dielectric constant (k) between 8 and 11 is demonstrated in thin-film transistors. Crosslinking P(VDF-BTFE) reduces energetic disorder at the dielectric-semiconductor interface by controlling the chain conformations of P(VDF-BTFE), thereby leading to approximately a threefold enhancement in the charge mobility of rubrene single-crystal field-effect transistors. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Nonperturbative results for two-index conformal windows

    Energy Technology Data Exchange (ETDEWEB)

    Bergner, Georg [Albert Einstein Center for Fundamental Physics,Institute for Theoretical Physics, University of Bern,Sidlerstrasse 5, CH-3012 Bern (Switzerland); Ryttov, Thomas A.; Sannino, Francesco [CP-Origins and the Danish IAS, University of Southern Denmark,5230 Odense M (Denmark)

    2015-12-10

    Via large and small N{sub c} relations we derive nonperturbative results about the conformal window of two-index theories. Using Schwinger-Dyson methods as well as four-loops results we estimate subleading corrections and show that naive large number of colors extrapolations are unreliable when N{sub c} is less than about six. Nevertheless useful nonperturbative inequalities for the size of the conformal windows, for any number of colors, can be derived. By further observing that the adjoint conformal window is independent of the number of colors we argue, among other things, that: the large N{sub c} two-index conformal window is twice the conformal window of the adjoint representation (which can be determined at small N{sub c}) expressed in terms of Dirac fermions; lattice results for adjoint matter can be used to provide independent information on the conformal dynamics of two-index theories such as SU(N{sub c}) with two and four symmetric Dirac flavors.

  12. Nonperturbative results for two-index conformal windows

    International Nuclear Information System (INIS)

    Bergner, Georg; Ryttov, Thomas A.; Sannino, Francesco

    2015-01-01

    Via large and small N c relations we derive nonperturbative results about the conformal window of two-index theories. Using Schwinger-Dyson methods as well as four-loops results we estimate subleading corrections and show that naive large number of colors extrapolations are unreliable when N c is less than about six. Nevertheless useful nonperturbative inequalities for the size of the conformal windows, for any number of colors, can be derived. By further observing that the adjoint conformal window is independent of the number of colors we argue, among other things, that: the large N c two-index conformal window is twice the conformal window of the adjoint representation (which can be determined at small N c ) expressed in terms of Dirac fermions; lattice results for adjoint matter can be used to provide independent information on the conformal dynamics of two-index theories such as SU(N c ) with two and four symmetric Dirac flavors.

  13. Measuring the mechanical properties of molecular conformers

    Science.gov (United States)

    Jarvis, S. P.; Taylor, S.; Baran, J. D.; Champness, N. R.; Larsson, J. A.; Moriarty, P.

    2015-09-01

    Scanning probe-actuated single molecule manipulation has proven to be an exceptionally powerful tool for the systematic atomic-scale interrogation of molecular adsorbates. To date, however, the extent to which molecular conformation affects the force required to push or pull a single molecule has not been explored. Here we probe the mechanochemical response of two tetra(4-bromophenyl)porphyrin conformers using non-contact atomic force microscopy where we find a large difference between the lateral forces required for manipulation. Remarkably, despite sharing very similar adsorption characteristics, variations in the potential energy surface are capable of prohibiting probe-induced positioning of one conformer, while simultaneously permitting manipulation of the alternative conformational form. Our results are interpreted in the context of dispersion-corrected density functional theory calculations which reveal significant differences in the diffusion barriers for each conformer. These results demonstrate that conformational variation significantly modifies the mechanical response of even simple porpyhrins, potentially affecting many other flexible molecules.

  14. Counselor Identity: Conformity or Distinction?

    Science.gov (United States)

    McLaughlin, Jerry E.; Boettcher, Kathryn

    2009-01-01

    The authors explore 3 debates in other disciplines similar to counseling's identity debate in order to learn about common themes and outcomes. Conformity, distinction, and cohesion emerged as common themes. They conclude that counselors should retain their distinctive, humanistic approach rather than conforming to the dominant, medical approach.

  15. Peer influence: neural mechanisms underlying in-group conformity.

    Science.gov (United States)

    Stallen, Mirre; Smidts, Ale; Sanfey, Alan G

    2013-01-01

    People often conform to the behavior of others with whom they identify. However, it is unclear what fundamental mechanisms underlie this type of conformity. Here, we investigate the processes mediating in-group conformity by using functional magnetic resonance imaging (fMRI). Participants completed a perceptual decision-making task while undergoing fMRI, during which they were exposed to the judgments of both in-group and out-group members. Our data suggest that conformity to the in-group is mediated by both positive affect as well as the cognitive capacity of perspective taking. Examining the processes that drive in-group conformity by utilizing a basic decision-making paradigm combined with neuroimaging methods provides important insights into the potential mechanisms of conformity. These results may provide an integral step in developing more effective campaigns using group conformity as a tool for behavioral change.

  16. 47 CFR 2.1072 - Limitation on Declaration of Conformity.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Limitation on Declaration of Conformity. 2.1072... Conformity § 2.1072 Limitation on Declaration of Conformity. (a) The Declaration of Conformity signifies that...'s rules. (b) A Declaration of Conformity by the responsible party is effective until a termination...

  17. Renormalization, conformal ward identities and the origin of a conformal anomaly pole

    Science.gov (United States)

    Corianò, Claudio; Maglio, Matteo Maria

    2018-06-01

    We investigate the emergence of a conformal anomaly pole in conformal field theories in the case of the TJJ correlator. We show how it comes to be generated in dimensional renormalization, using a basis of 13 form factors (the F-basis), where only one of them requires renormalization (F13), extending previous studies. We then combine recent results on the structure of the non-perturbative solutions of the conformal Ward identities (CWI's) for the TJJ in momentum space, expressed in terms of a minimal set of 4 form factors (A-basis), with the properties of the F-basis, and show how the singular behaviour of the corresponding form factors in both basis can be related. The result proves the centrality of such massless effective interactions induced by the anomaly, which have recently found realization in solid state, in the theory of topological insulators and of Weyl semimetals. This pattern is confirmed in massless abelian and nonabelian theories (QED and QCD) investigated at one-loop.

  18. Conformable variational iteration method

    Directory of Open Access Journals (Sweden)

    Omer Acan

    2017-02-01

    Full Text Available In this study, we introduce the conformable variational iteration method based on new defined fractional derivative called conformable fractional derivative. This new method is applied two fractional order ordinary differential equations. To see how the solutions of this method, linear homogeneous and non-linear non-homogeneous fractional ordinary differential equations are selected. Obtained results are compared the exact solutions and their graphics are plotted to demonstrate efficiency and accuracy of the method.

  19. 40 CFR 90.106 - Certificate of conformity.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Certificate of conformity. 90.106... Standards and Certification Provisions § 90.106 Certificate of conformity. (a)(1) Except as provided in § 90... certificate of conformity covering such engines; however, engines manufactured during an annual production...

  20. SU-F-T-420: Dosimetry Comparison of Advanced External Beam Radiation Treatment Modalities to Brachytherapy Treatments in Patients with Cervical Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Mwidu, U; Devic, S [McGill University, Montreal, QC (Canada); Shehadeh, M; AlKafi, M; Mahmood, R; Moftah, B [King Faisal Specialist Hospital & Research Center, Riyadh, Riyadh (Saudi Arabia)

    2016-06-15

    Purpose: A retrospective comparison of dose distributions achievable by High dose rate brachytherapy (HDRBT), Helical TomoTherapy (TOMO), CyberKnife (CK) and RapidArc (RA) in locally advanced inoperable cervical cancer patients is presented. Methods: Five patients with advanced stage cervical carcinoma were selected for this study after a full course of external beam radiotherapy (EBRT), chemotherapy and HDR Brachytherapy. To highlight any significant similarities/differences in dose distributions, high-risk clinical target volume (HRCTV) coverage, organs at risk (OAR) sparing, and machine specific delivery limitations, we used D90 (dose received by 90% of the volume) as the parameter for HRCTV coverage as recommended by the GEC-ESTRO Working Group. We also compared both integral and differential dose volume histograms (DVH) between different dose distributions treatment modalities for HRCTV and OAR. Results: TOMO and RA provided the most conformal dose distributions to HRCTV. Median doses (in Gy) to organs at risk were; for rectal wall: 1.7±0.6, 2.5±0.6,1.2±0.3, and 1.5±0.6, and for bladder wall: 1.6±0.1, 2.4±0.4, 0.8±0.6, and 1.5±0.5, for HDRBT, TOMO, CK, and RA, respectively. Conclusion: Contemporary EBRT modalities might be able to replace brachytherapy treatments for cervix cancer. While brachytherapy dose distributions feature high dose gradients, EBRT modalities provide highly conformal dose distributions to the target. However, it is still not clear whether a highly conformal dose or high gradient dose is more clinically relevant for the HRCTV in cervix cancer patients.

  1. SCit: web tools for protein side chain conformation analysis

    OpenAIRE

    Gautier, R.; Camproux, A.-C.; Tufféry, P.

    2004-01-01

    SCit is a web server providing services for protein side chain conformation analysis and side chain positioning. Specific services use the dependence of the side chain conformations on the local backbone conformation, which is described using a structural alphabet that describes the conformation of fragments of four-residue length in a limited library of structural prototypes. Based on this concept, SCit uses sets of rotameric conformations dependent on the local backbone conformation of each...

  2. 6d dual conformal symmetry and minimal volumes in AdS

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Jyotirmoy; Lipstein, Arthur E. [Centre for Particle Theory & Department of Mathematical Sciences, Durham University,South Road, Durham DH1 3LE (United Kingdom)

    2016-12-20

    The S-matrix of a theory often exhibits symmetries which are not manifest from the viewpoint of its Lagrangian. For instance, powerful constraints on scattering amplitudes are imposed by the dual conformal symmetry of planar 4d N=4 super Yang-Mills theory and the ABJM theory. Motivated by this, we investigate the consequences of dual conformal symmetry in six dimensions, which may provide useful insight into the worldvolume theory of M5-branes (if it enjoys such a symmetry). We find that 6d dual conformal symmetry uniquely fixes the integrand of the one-loop 4-point amplitude, and its structure suggests a Lagrangian with more than two derivatives. On integrating out the loop momentum in 6−2ϵ dimensions, the result is very similar to the corresponding amplitude of N=4 super Yang-Mills theory. We confirm this result holographically by generalizing the Alday-Maldacena solution for a minimal area string in Anti-de Sitter space to a minimal volume M2-brane ending on a pillow-shaped surface in the boundary whose seams correspond to a null-polygon. This involves careful treatment of a prefactor which diverges as 1/ϵ, and we comment on its possible interpretation. We also study 2-loop 4-point integrands with 6d dual conformal symmetry and speculate on the existence of an all-loop formula for the 4-point amplitude.

  3. Image-guided conformation arc therapy for prostate cancer: Early side effects

    International Nuclear Information System (INIS)

    Soete, Guy; Verellen, Dirk; Michielsen, Dirk; Rappe, Bernard; Keuppen, Frans; Storme, Guy

    2006-01-01

    Purpose: To evaluate early side effects in prostate cancer patients treated with image-guided conformation arc therapy (IGCAT) using a minimultileaf collimator and daily X-ray-assisted patient positioning. Methods and Materials: Between May 2000 and November 2004, 238 cT1-T3N0M0 tumors were treated with doses of 70 or 78 Gy. Seventy patients also received neoadjuvant or concurrent hormonal treatment. Median follow-up is 18 months (range, 4-55 months). Radiation Therapy Oncology Group and the European Organization for Research and Treatment of Cancer toxicity scoring system was used to evaluate early side effects. Results: Grade 1, 2, and >2 acute side effects occurred in 19, 6, and 0% (gastrointestinal) and 37, 16, and 0% (genitourinary) of the patients. No relation between radiation dose and early side effects was observed. Conclusion: Patients treated with image-guided conformation arc therapy experience a low rate of Grade 2 (i.e., requiring medication) early side effects. The definitive evaluation of late side effects and biochemical control requires further follow-up

  4. SCit: web tools for protein side chain conformation analysis.

    Science.gov (United States)

    Gautier, R; Camproux, A-C; Tufféry, P

    2004-07-01

    SCit is a web server providing services for protein side chain conformation analysis and side chain positioning. Specific services use the dependence of the side chain conformations on the local backbone conformation, which is described using a structural alphabet that describes the conformation of fragments of four-residue length in a limited library of structural prototypes. Based on this concept, SCit uses sets of rotameric conformations dependent on the local backbone conformation of each protein for side chain positioning and the identification of side chains with unlikely conformations. The SCit web server is accessible at http://bioserv.rpbs.jussieu.fr/SCit.

  5. Conformal Killing horizons and their thermodynamics

    Science.gov (United States)

    Nielsen, Alex B.; Shoom, Andrey A.

    2018-05-01

    Certain dynamical black hole solutions can be mapped to static spacetimes by conformal metric transformations. This mapping provides a physical link between the conformal Killing horizon of the dynamical black hole and the Killing horizon of the static spacetime. Using the Vaidya spacetime as an example, we show how this conformal relation can be used to derive thermodynamic properties of such dynamical black holes. Although these horizons are defined quasi-locally and can be located by local experiments, they are distinct from other popular notions of quasi-local horizons such as apparent horizons. Thus in the dynamical Vaidya spacetime describing constant accretion of null dust, the conformal Killing horizon, which is null by construction, is the natural horizon to describe the black hole.

  6. Molecular dynamics studies of the conformation of sorbitol

    Science.gov (United States)

    Lerbret, A.; Mason, P.E.; Venable, R.M.; Cesàro, A.; Saboungi, M.-L.; Pastor, R.W.; Brady, J.W.

    2009-01-01

    Molecular dynamics simulations of a 3 m aqueous solution of D-sorbitol (also called D-glucitol) have been performed at 300 K, as well as at two elevated temperatures to promote conformational transitions. In principle, sorbitol is more flexible than glucose since it does not contain a constraining ring. However, a conformational analysis revealed that the sorbitol chain remains extended in solution, in contrast to the bent conformation found experimentally in the crystalline form. While there are 243 staggered conformations of the backbone possible for this open-chain polyol, only a very limited number were found to be stable in the simulations. Although many conformers were briefly sampled, only eight were significantly populated in the simulation. The carbon backbones of all but two of these eight conformers were completely extended, unlike the bent crystal conformation. These extended conformers were stabilized by a quite persistent intramolecular hydrogen bond between the hydroxyl groups of carbon C-2 and C-4. The conformational populations were found to be in good agreement with the limited available NMR data except for the C-2–C-3 torsion (spanned by the O-2–O-4 hydrogen bond), where the NMR data supports a more bent structure. PMID:19744646

  7. Kinetics of conformational changes of fibronectin adsorbed onto model surfaces.

    Science.gov (United States)

    Baujard-Lamotte, L; Noinville, S; Goubard, F; Marque, P; Pauthe, E

    2008-05-01

    Fibronectin (FN), a large glycoprotein found in body fluids and in the extracellular matrix, plays a key role in numerous cellular behaviours. We investigate FN adsorption onto hydrophilic bare silica and hydrophobic polystyrene (PS) surfaces using Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR) in aqueous medium. Adsorption kinetics using different bulk concentrations of FN were followed for 2h and the surface density of adsorbed FN and its time-dependent conformational changes were determined. When adsorption occurs onto the hydrophilic surface, FN molecules keep their native conformation independent of the adsorption conditions, but the amount of adsorbed FN increases with time and the bulk concentration. Although the protein surface density is the same on the hydrophobic PS surface, this has a strong impact on the average conformation of the adsorbed FN layer. Indeed, interfacial hydration changes induced by adsorption onto the hydrophobic surface lead to a decrease in unhydrated beta-sheet content and cause an increase in hydrated beta-strand and hydrated random domain content of adsorbed FN. This conformational change is mainly dependent on the bulk concentration. Indeed, at low bulk concentrations, the secondary structures of adsorbed FN molecules undergo strong unfolding, allowing an extended and hydrated conformation of the protein. At high bulk concentrations, the molecular packing reduces the unfolding of the stereoregular structures of the FN molecules, preventing stronger spreading of the protein.

  8. Lattice models and conformal field theories

    International Nuclear Information System (INIS)

    Saleur, H.

    1988-01-01

    Theoretical studies concerning the connection between critical physical systems and the conformal theories are reviewed. The conformal theory associated to a critical (integrable) lattice model is derived. The obtention of the central charge, critical exponents and torus partition function, using renormalization group arguments, is shown. The quantum group structure, in the integrable lattice models, and the theory of Visaro algebra representations are discussed. The relations between off-critical integrable models and conformal theories, in finite geometries, are studied

  9. Impact of Different CT Slice Thickness on Clinical Target Volume for 3D Conformal Radiation Therapy

    International Nuclear Information System (INIS)

    Prabhakar, Ramachandran; Ganesh, Tharmar; Rath, Goura K.; Julka, Pramod K.; Sridhar, Pappiah S.; Joshi, Rakesh C.; Thulkar, Sanjay

    2009-01-01

    The purpose of this study was to present the variation of clinical target volume (CTV) with different computed tomography (CT) slice thicknesses and the impact of CT slice thickness on 3-dimensional (3D) conformal radiotherapy treatment planning. Fifty patients with brain tumors were selected and CT scans with 2.5-, 5-, and 10-mm slice thicknesses were performed with non-ionic contrast enhancement. The patients were selected with tumor volume ranging from 2.54 cc to 222 cc. Three-dimensional treatment planning was performed for all three CT datasets. The target coverage and the isocenter shift between the treatment plans for different slice thickness were correlated with the tumor volume. An important observation from our study revealed that for volume 25 cc, the target underdosage was less than 6.7% for 5-mm slice thickness and 8% for 10-mm slice thickness. For 3D conformal radiotherapy treatment planning (3DCRT), a CT slice thickness of 2.5 mm is optimum for tumor volume 25 cc

  10. An Improved Methodology for Multidimensional High-Throughput Preformulation Characterization of Protein Conformational Stability

    Science.gov (United States)

    Maddux, Nathaniel R.; Rosen, Ilan T.; Hu, Lei; Olsen, Christopher M.; Volkin, David B.; Middaugh, C. Russell

    2013-01-01

    The Empirical Phase Diagram (EPD) technique is a vector-based multidimensional analysis method for summarizing large data sets from a variety of biophysical techniques. It can be used to provide comprehensive preformulation characterization of a macromolecule’s higher-order structural integrity and conformational stability. In its most common mode, it represents a type of stimulus-response diagram using environmental variables such as temperature, pH, and ionic strength as the stimulus, with alterations in macromolecular structure being the response. Until now EPD analysis has not been available in a high throughput mode because of the large number of experimental techniques and environmental stressor/stabilizer variables typically employed. A new instrument has been developed that combines circular dichroism, UV-absorbance, fluorescence spectroscopy and light scattering in a single unit with a 6-position temperature controlled cuvette turret. Using this multifunctional instrument and a new software system we have generated EPDs for four model proteins. Results confirm the reproducibility of the apparent phase boundaries and protein behavior within the boundaries. This new approach permits two EPDs to be generated per day using only 0.5 mg of protein per EPD. Thus, the new methodology generates reproducible EPDs in high-throughput mode, and represents the next step in making such determinations more routine. PMID:22447621

  11. Evaluation of homogeneity and dose conformity in IMRT planning in prostate radiotherapy

    International Nuclear Information System (INIS)

    Lopes, Juliane S.; Leidens, Matheus; Estacio, Daniela R.; Razera, Ricardo A.Z.; Streck, Elaine E.; Silva, Ana M.M. da

    2015-01-01

    The goal of this study was to evaluate the dose distribution homogeneity and conformity of radiation therapy plans of prostate cancer using IMRT. Data from 34 treatment plans of Hospital Sao Lucas of PUCRS, where those plans were executed, were retrospectively analyzed. All of them were done with 6MV X-rays from a linear accelerator CLINAC IX, and the prescription doses varied between 60 and 74 Gy. Analyses showing the homogeneity and conformity indices for the dose distribution of those plans were made. During these analyses, some comparisons with the traditional radiation therapy planning technic, the 3D-CRT, were discussed. The results showed that there is no correlation between the prescribed dose and the homogeneity and conformity indices, indicating that IMRT works very well even for higher doses. Furthermore, a comparison between the results obtained and the recommendations of ICRU 83 was carried out. It has also been observed that the indices were really close to the ideal values. 82.4% of the cases showed a difference below 5% of the ideal value for the index of conformity, and 88.2% showed a difference below 10% for the homogeneity index. Concluding, it is possible to confirm the quality of the analyzed radiation therapy plans of prostate cancer using IMRT. (author)

  12. 14 CFR 21.130 - Statement of conformity.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Statement of conformity. 21.130 Section 21... conformity. Each holder or licensee of a type certificate only, for a product manufactured in the United... Administrator a statement of conformity (FAA Form 317). This statement must be signed by an authorized person...

  13. 14 CFR 21.53 - Statement of conformity.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Statement of conformity. 21.53 Section 21... CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS Type Certificates § 21.53 Statement of conformity. Link to an... conformity (FAA Form 317) to the Administrator for each aircraft engine and propeller presented to the...

  14. Delineating the conformal window

    DEFF Research Database (Denmark)

    Frandsen, Mads Toudal; Pickup, Thomas; Teper, Michael

    2011-01-01

    We identify and characterise the conformal window in gauge theories relevant for beyond the standard model building, e.g. Technicolour, using the criteria of metric confinement and causal analytic couplings, which are known to be consistent with the phase diagram of supersymmetric QCD from Seiberg...... duality. Using these criteria we find perturbation theory to be consistent throughout the predicted conformal window for several of these gauge theories and we discuss recent lattice results in the light of our findings....

  15. Conformation, orientation and interaction in molecular monolayers

    International Nuclear Information System (INIS)

    Superfine, R.; Huang, J.Y.; Shen, Y.R.

    1989-01-01

    Knowledge of the conformation and ordering of molecular monolayers is essential for a detailed understanding of a wide variety of surface and interfacial phenomena. Over the past several years, surface second harmonic generation (SHG) has proven to be a valuable and versatile probe of monolayer systems. Our group has recently extended the technique to infrared-visible sum frequency generation (SFG) which has unique capabilities for surface vibrational spectroscopy. Like second harmonic generation, SFG is highly surface specific with submonolayer sensitivity at all interfaces accessible by light. The orientation of individual groups within an adsorbate molecule can be deduced by a polarization analysis of the SFG signal from the vibrational modes of the groups. The authors have used SHG and SFG to study orientations and conformations of surfactant and liquid crystal (LC) monolayers and their interaction on a substrate. The interfacial properties of LC are of great interest to many researchers for both basic science understanding and practical application to LC devices. It is well known that the bulk alignment of a liquid crystal in a cell is strongly affected by the surface treatment of the cell walls. The reason behind it is not yet clear. The theoretical background and experimental arrangement of SHG and SFG have been described elsewhere. In the setup, a 30 psec. Nd:YAG mode-locked laser system together with nonlinear accessories generates a visible beam at .532μm and an infrared beam tunable about 3.4μm. Both beams are focused to a common spot of 300μm dia. The typical signal off the surface from a compact ordered alkyl chain monolayer is ∼500 photons per pulse, easily detected with a photomultiplier tube

  16. Rapid roll inflation with conformal coupling

    International Nuclear Information System (INIS)

    Kofman, Lev; Mukohyama, Shinji

    2008-01-01

    Usual inflation is realized with a slow rolling scalar field minimally coupled to gravity. In contrast, we consider dynamics of a scalar with a flat effective potential, conformally coupled to gravity. Surprisingly, it contains an attractor inflationary solution with the rapidly rolling inflaton field. We discuss models with the conformal inflaton with a flat potential (including hybrid inflation). There is no generation of cosmological fluctuations from the conformally coupled inflaton. We consider realizations of modulated (inhomogeneous reheating) or curvaton cosmological fluctuations in these models. We also implement these unusual features for the popular string-theoretic warped inflationary scenario, based on the interacting D3-D3 branes. The original warped brane inflation suffers a large inflaton mass due to conformal coupling to 4-dimensional gravity. Instead of considering this as a problem and trying to cure it with extra engineering, we show that warped inflation with the conformally coupled, rapidly rolling inflaton is yet possible with N=37 efoldings, which requires low-energy scales 1-100 TeV of inflation. Coincidentally, the same warping numerology can be responsible for the hierarchy. It is shown that the scalars associated with angular isometries of the warped geometry of compact manifold (e.g. S 3 of Klebanov-Strassler (KS) geometry) have solutions identical to conformally coupled modes and also cannot be responsible for cosmological fluctuations. We discuss other possibilities

  17. Rapid roll inflation with conformal coupling

    Science.gov (United States)

    Kofman, Lev; Mukohyama, Shinji

    2008-02-01

    Usual inflation is realized with a slow rolling scalar field minimally coupled to gravity. In contrast, we consider dynamics of a scalar with a flat effective potential, conformally coupled to gravity. Surprisingly, it contains an attractor inflationary solution with the rapidly rolling inflaton field. We discuss models with the conformal inflaton with a flat potential (including hybrid inflation). There is no generation of cosmological fluctuations from the conformally coupled inflaton. We consider realizations of modulated (inhomogeneous reheating) or curvaton cosmological fluctuations in these models. We also implement these unusual features for the popular string-theoretic warped inflationary scenario, based on the interacting D3-D¯3 branes. The original warped brane inflation suffers a large inflaton mass due to conformal coupling to 4-dimensional gravity. Instead of considering this as a problem and trying to cure it with extra engineering, we show that warped inflation with the conformally coupled, rapidly rolling inflaton is yet possible with N=37 efoldings, which requires low-energy scales 1 100 TeV of inflation. Coincidentally, the same warping numerology can be responsible for the hierarchy. It is shown that the scalars associated with angular isometries of the warped geometry of compact manifold (e.g. S3 of Klebanov-Strassler (KS) geometry) have solutions identical to conformally coupled modes and also cannot be responsible for cosmological fluctuations. We discuss other possibilities.

  18. Conformal collineations and anisotropic fluids in general relativity

    International Nuclear Information System (INIS)

    Duggal, K.L.; Sharma, R.

    1986-01-01

    Recently, Herrera et al. [L. Herrera, J. Jimenez, L. Leal, J. Ponce de Leon, M. Esculpi, and V. Galino, J. Math. Phys. 25, 3274 (1984)] studied the consequences of the existence of a one-parameter group of conformal motions for anisotropic matter. They concluded that for special conformal motions, the stiff equation of state (p = μ) is singled out in a unique way, provided the generating conformal vector field is orthogonal to the four-velocity. In this paper, the same problem is studied by using conformal collineations (which include conformal motions as subgroups). It is shown that, for a special conformal collineation, the stiff equation of state is not singled out. Non-Einstein Ricci-recurrent spaces are considered as physical models for the fluid matter

  19. Manufacturing and metrology for IR conformal windows and domes

    Science.gov (United States)

    Ferralli, Ian; Blalock, Todd; Brunelle, Matt; Lynch, Timothy; Myer, Brian; Medicus, Kate

    2017-05-01

    Freeform and conformal optics have the potential to dramatically improve optical systems by enabling systems with fewer optical components, reduced aberrations, and improved aerodynamic performance. These optical components differ from standard components in their surface shape, typically a non-symmetric equation based definition, and material properties. Traditional grinding and polishing tools are unable to handle these freeform shapes. Additionally, standard metrology tools cannot measure these surfaces. Desired substrates are typically hard ceramics, including poly-crystalline alumina or aluminum oxynitride. Notwithstanding the challenges that the hardness provides to manufacturing, these crystalline materials can be highly susceptible to grain decoration creating unacceptable scatter in optical systems. In this presentation, we will show progress towards addressing the unique challenges of manufacturing conformal windows and domes. Particular attention is given to our robotic polishing platform. This platform is based on an industrial robot adapted to accept a wide range of tooling and parts. The robot's flexibility has provided us an opportunity to address the unique challenges of conformal windows. Slurries and polishing active layers can easily be changed to adapt to varying materials and address grain decoration. We have the flexibility to change tool size and shape to address the varying sizes and shapes of conformal optics. In addition, the robotic platform can be a base for a deflectometry-based metrology tool to measure surface form error. This system, whose precision is independent of the robot's positioning accuracy, will allow us to measure optics in-situ saving time and reducing part risk. In conclusion, we will show examples of the conformal windows manufactured using our developed processes.

  20. Swedish women's perceptions of and conformity to feminine norms.

    Science.gov (United States)

    Kling, Johanna; Holmqvist Gattario, Kristina; Frisén, Ann

    2017-06-01

    The relatively high gender equality in the Swedish society is likely to exert an influence on gender role construction. Hence, the present research aimed to investigate Swedish women's perceptions of and conformity to feminine norms. A mixed methods approach with two studies was used. In Study 1, young Swedish women's gender role conformity, as measured by the Conformity to Feminine Norms Inventory 45 (CFNI-45), was compared to the results from previously published studies in Canada, the United States, and Slovakia. Overall, Swedish women displayed less conformity than their foreign counterparts, with the largest difference on the subscale Sexual fidelity. In Study 2, focus group interviews with young Swedish women added a more complex picture of feminine norms in the Swedish society. For instance the results indicated that Swedish women, while living in a society with a strong gender equality discourse, are torn between the perceived need to invest in their appearances and the risk of being viewed as non-equal when doing so. In sum, despite the fact that traditional gender roles are less pronounced in Sweden, gender role conformity is still a pressing issue. Since attending to the potential roles of feminine norms in women's lives previously has been proposed to be useful in counseling and therapeutic work, the present research also offers valuable information for both researchers and practitioners. [Correction added on 5 May 2017, after first online publication in April 2017: An incorrect Abstract was inadvertently captured in the published article and has been corrected in this current version.]. © 2017 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

  1. High energy asymptotics of multi-colour QCD and two-dimensional conformal field theories

    International Nuclear Information System (INIS)

    Lipatov, L.N.; Deutsches Elektronen-Synchrotron

    1993-04-01

    In the multi-colour limit of perturbative QCD the holomorphic factorization of wave functions of compound states of n reggeized gluons in the impact parameter space is shown. The conformally invariant Hamiltonian for each holomorphic factor has a nontrivial integral of motion. The odderon in QCD is the simplest example of the composite system with these properties. (orig.)

  2. Bioactive focus in conformational ensembles: a pluralistic approach

    Science.gov (United States)

    Habgood, Matthew

    2017-12-01

    Computational generation of conformational ensembles is key to contemporary drug design. Selecting the members of the ensemble that will approximate the conformation most likely to bind to a desired target (the bioactive conformation) is difficult, given that the potential energy usually used to generate and rank the ensemble is a notoriously poor discriminator between bioactive and non-bioactive conformations. In this study an approach to generating a focused ensemble is proposed in which each conformation is assigned multiple rankings based not just on potential energy but also on solvation energy, hydrophobic or hydrophilic interaction energy, radius of gyration, and on a statistical potential derived from Cambridge Structural Database data. The best ranked structures derived from each system are then assembled into a new ensemble that is shown to be better focused on bioactive conformations. This pluralistic approach is tested on ensembles generated by the Molecular Operating Environment's Low Mode Molecular Dynamics module, and by the Cambridge Crystallographic Data Centre's conformation generator software.

  3. CONFORMITY IN CHRIST 1. THE TRANSFORMATION PROCESS

    African Journals Online (AJOL)

    This essay investigates the notion of conformity in Christ as it is part of a compre- hensive, multilayered process of transformation. In the first part it focuses on the process of transformation in creation, re-creation, conformity, love and glory. In the second part it discusses transformation in Christ by looking at conformation and ...

  4. Conformal invariance in harmonic superspace

    International Nuclear Information System (INIS)

    Galperin, A.; Ivanov, E.; Ogievetsky, V.; Sokatchev, E.

    1985-01-01

    N=2 conformal supersymmetry is realized in harmonic superspace, its peculiarities are analyzed. The coordinate group and analytical prepotentials for N=2 conformal supergravity are found. A new version of the N=2 Einstein supergravity with infinite number of auxiliary fields is suggested. A hypermultiplet without central charges and constraints is used as a compensator

  5. New open conformation of SMYD3 implicates conformational selection and allostery

    Directory of Open Access Journals (Sweden)

    Nicholas Spellmon

    2016-12-01

    Full Text Available SMYD3 plays a key role in cancer cell viability, adhesion, migration and invasion. SMYD3 promotes formation of inducible regulatory T cells and is involved in reducing autoimmunity. However, the nearly “closed” substrate-binding site and poor in vitro H3K4 methyltransferase activity have obscured further understanding of this oncogenically related protein. Here we reveal that SMYD3 can adopt an “open” conformation using molecular dynamics simulation and small-angle X-ray scattering. This ligand-binding-capable open state is related to the crystal structure-like closed state by a striking clamshell-like inter-lobe dynamics. The two states are characterized by many distinct structural and dynamical differences and the conformational transition pathway is mediated by a reversible twisting motion of the C-terminal domain (CTD. The spontaneous transition from the closed to open states suggests two possible, mutually non-exclusive models for SMYD3 functional regulation and the conformational selection mechanism and allostery may regulate the catalytic or ligand binding competence of SMYD3. This study provides an immediate clue to the puzzling role of SMYD3 in epigenetic gene regulation.

  6. Design of conformal cooling for plastic injection moulding by heat transfer simulation

    Directory of Open Access Journals (Sweden)

    Sabrina Marques

    2015-12-01

    Full Text Available The cooling channels of a mold for plastic injection have to be as close as possible to the part geometry in order to ensure fast and homogeneous cooling. However, conventional methods to manufacture cooling channels (drilling can only produce linear holes. Selective laser melting (SLM is an additive manufacturing technique capable to manufacture complex cooling channels (known as conformal cooling. Nevertheless, because of the high costs of SLM the benefits of conformal collings are still not clear. The current work investigates two designs of conformal coolings: i parallel circuit; ii serial circuit. Both coolings are evaluated against to traditional cooling circuits (linear channels by CAE simulation to produce parts of polypropylene. The results show that if the conformal cooling is not properly designed it cannot provide reasonable results. The deformation of the product can be reduced significantly after injection but the cycle time reduced not more than 6%.

  7. Reciprocity Outperforms Conformity to Promote Cooperation.

    Science.gov (United States)

    Romano, Angelo; Balliet, Daniel

    2017-10-01

    Evolutionary psychologists have proposed two processes that could give rise to the pervasiveness of human cooperation observed among individuals who are not genetically related: reciprocity and conformity. We tested whether reciprocity outperformed conformity in promoting cooperation, especially when these psychological processes would promote a different cooperative or noncooperative response. To do so, across three studies, we observed participants' cooperation with a partner after learning (a) that their partner had behaved cooperatively (or not) on several previous trials and (b) that their group members had behaved cooperatively (or not) on several previous trials with that same partner. Although we found that people both reciprocate and conform, reciprocity has a stronger influence on cooperation. Moreover, we found that conformity can be partly explained by a concern about one's reputation-a finding that supports a reciprocity framework.

  8. Free-breathing conformal irradiation of pancreatic cancer.

    Science.gov (United States)

    Solla, Ignazio; Zucca, Sergio; Possanzini, Marco; Piras, Sara; Pusceddu, Claudio; Porru, Sergio; Meleddu, Gianfranco; Farace, Paolo

    2013-07-08

    The purpose of this study was to assess treatment margins in free-breathing irradiation of pancreatic cancer after bone alignment, and evaluate their impact on conformal radiotherapy. Fifteen patients with adenocarcinoma of the head of the pancreas underwent implantation of single fiducial marker. Intrafraction uncertainties were assessed on simulation four-dimensional computed tomography (4D CT) by calculating maximal intrafraction fiducial excursion (MIFE). In the first ten patients, after bony alignment, the position of the fiducial was identified on weekly acquired megavolt cone-beam CT (MV-CBCT). The interfraction residual uncertainties were estimated by measuring the fiducial displacements with respect to the position in the first session. Patient mean (pM) and patient standard deviation (pSD) of fiducial displacement, mean (μM) and standard deviation (μSD) of pM, and root-mean-square of pSD (σ(res)) were calculated. In the other five patients, MIFE was added to the residual component to obtain personalized margin. In these patients, conformal kidney sparing (CONKISS) irradiation was planned prescribing 54/45 Gy to PTV1/PTV2. The organ-at-risk limits were set according to current NCCN recommendation. No morbidity related to the fiducial marker implantation was recorded. In the first ten patients, along right-left, anterior-posterior, and inferior-superior directions, MIFE was variable (mean ± std = 0.24 ± 0.13 cm, 0.31 ± 0.14 cm, 0.83 ± 0.35 cm, respectively) and was at most 0.51, 0.53, and 1.56 cm, respectively. Along the same directions, μM were 0.09, -0.05, -0.05 cm, μSD were 0.30, 0.17, 0.33 cm, and σ(res) were 0.35, 0.26, and 0.30 cm, respectively. MIFE was not correlated with pM and pSD. In the five additional patients, it was possible to satisfy recommended dose limits, with the exception of slightly higher doses to small bowel. After bony alignment, the margins for target expansion can be obtained by adding personalized MIFE to the residual

  9. Reduction of treatment delivery variances with a computer-controlled treatment delivery system

    International Nuclear Information System (INIS)

    Fraass, B.A.; Lash, K.L.; Matrone, G.M.; Lichter, A.S.

    1997-01-01

    Purpose: To analyze treatment delivery variances for 3-D conformal therapy performed at various levels of treatment delivery automation, ranging from manual field setup to virtually complete computer-controlled treatment delivery using a computer-controlled conformal radiotherapy system. Materials and Methods: All external beam treatments performed in our department during six months of 1996 were analyzed to study treatment delivery variances versus treatment complexity. Treatments for 505 patients (40,641 individual treatment ports) on four treatment machines were studied. All treatment variances noted by treatment therapists or quality assurance reviews (39 in all) were analyzed. Machines 'M1' (CLinac (6(100))) and 'M2' (CLinac 1800) were operated in a standard manual setup mode, with no record and verify system (R/V). Machines 'M3' (CLinac 2100CD/MLC) and ''M4'' (MM50 racetrack microtron system with MLC) treated patients under the control of a computer-controlled conformal radiotherapy system (CCRS) which 1) downloads the treatment delivery plan from the planning system, 2) performs some (or all) of the machine set-up and treatment delivery for each field, 3) monitors treatment delivery, 4) records all treatment parameters, and 5) notes exceptions to the electronically-prescribed plan. Complete external computer control is not available on M3, so it uses as many CCRS features as possible, while M4 operates completely under CCRS control and performs semi-automated and automated multi-segment intensity modulated treatments. Analysis of treatment complexity was based on numbers of fields, individual segments (ports), non-axial and non-coplanar plans, multi-segment intensity modulation, and pseudo-isocentric treatments (and other plans with computer-controlled table motions). Treatment delivery time was obtained from the computerized scheduling system (for manual treatments) or from CCRS system logs. Treatment therapists rotate among the machines, so this analysis

  10. Lipid Regulated Intramolecular Conformational Dynamics of SNARE-Protein Ykt6

    Science.gov (United States)

    Dai, Yawei; Seeger, Markus; Weng, Jingwei; Song, Song; Wang, Wenning; Tan, Yan-Wen

    2016-08-01

    Cellular informational and metabolic processes are propagated with specific membrane fusions governed by soluble N-ethylmaleimide sensitive factor attachment protein receptors (SNARE). SNARE protein Ykt6 is highly expressed in brain neurons and plays a critical role in the membrane-trafficking process. Studies suggested that Ykt6 undergoes a conformational change at the interface between its longin domain and the SNARE core. In this work, we study the conformational state distributions and dynamics of rat Ykt6 by means of single-molecule Förster Resonance Energy Transfer (smFRET) and Fluorescence Cross-Correlation Spectroscopy (FCCS). We observed that intramolecular conformational dynamics between longin domain and SNARE core occurred at the timescale ~200 μs. Furthermore, this dynamics can be regulated and even eliminated by the presence of lipid dodecylphoshpocholine (DPC). Our molecular dynamic (MD) simulations have shown that, the SNARE core exhibits a flexible structure while the longin domain retains relatively stable in apo state. Combining single molecule experiments and theoretical MD simulations, we are the first to provide a quantitative dynamics of Ykt6 and explain the functional conformational change from a qualitative point of view.

  11. Essential role of conformational selection in ligand binding.

    Science.gov (United States)

    Vogt, Austin D; Pozzi, Nicola; Chen, Zhiwei; Di Cera, Enrico

    2014-02-01

    Two competing and mutually exclusive mechanisms of ligand recognition - conformational selection and induced fit - have dominated our interpretation of ligand binding in biological macromolecules for almost six decades. Conformational selection posits the pre-existence of multiple conformations of the macromolecule from which the ligand selects the optimal one. Induced fit, on the other hand, postulates the existence of conformational rearrangements of the original conformation into an optimal one that are induced by binding of the ligand. In the former case, conformational transitions precede the binding event; in the latter, conformational changes follow the binding step. Kineticists have used a facile criterion to distinguish between the two mechanisms based on the dependence of the rate of relaxation to equilibrium, kobs, on the ligand concentration, [L]. A value of kobs decreasing hyperbolically with [L] has been seen as diagnostic of conformational selection, while a value of kobs increasing hyperbolically with [L] has been considered diagnostic of induced fit. However, this simple conclusion is only valid under the rather unrealistic assumption of conformational transitions being much slower than binding and dissociation events. In general, induced fit only produces values of kobs that increase with [L] but conformational selection is more versatile and is associated with values of kobs that increase with, decrease with or are independent of [L]. The richer repertoire of kinetic properties of conformational selection applies to kinetic mechanisms with single or multiple saturable relaxations and explains the behavior of nearly all experimental systems reported in the literature thus far. Conformational selection is always sufficient and often necessary to account for the relaxation kinetics of ligand binding to a biological macromolecule and is therefore an essential component of any binding mechanism. On the other hand, induced fit is never necessary and

  12. Rotational Spectroscopy Unveils Eleven Conformers of Adrenaline

    Science.gov (United States)

    Cabezas, C.; Cortijo, V.; Mata, S.; Lopez, J. C.; Alonso, J. L.

    2013-06-01

    Recent improvements in our LA-MB-FTMW instrumentation have allowed the characterization of eleven and eight conformers for the neurotransmitters adrenaline and noradrenaline respectively. The observation of this rich conformational behavior is in accordance with the recent observation of seven conformers for dopamine and in sharp contrast with the conformational reduction proposed for catecholamines. C. Cabezas, I. Peña, J. C. López, J. L. Alonso J. Phys. Chem. Lett. 2013, 4, 486. H. Mitsuda, M. Miyazaki, I. B. Nielsen, P. Carcabal,C. Dedonder, C. Jouvet, S. Ishiuchi, M. Fujii J. Phys. Chem. Lett. 2010, 1, 1130.

  13. Dilogarithm identities in conformal field theory

    International Nuclear Information System (INIS)

    Nahm, W.; Recknagel, A.; Terhoeven, M.

    1992-11-01

    Dilogarithm identities for the central charges and conformal dimensions exist for at least large classes of rational conformally invariant quantum field theories in two dimensions. In many cases, proofs are not yet known but the numerical and structural evidence is convincing. In particular, close relations exist to fusion rules and partition identities. We describe some examples and ideas, and present conjectures useful for the classification of conformal theories. The mathematical structures seem to be dual to Thurston's program for the classification of 3-manifolds. (orig.)

  14. Salvage conformal radiotherapy for biochemical recurrent prostate cancer after radical prostatectomy

    Directory of Open Access Journals (Sweden)

    Carlos R. Monti

    2006-08-01

    Full Text Available OBJECTIVE: Assess the results of salvage conformal radiotherapy in patients with biochemical failure after radical prostatectomy and identify prognostic factors for biochemical recurrence and toxicity of the treatment. MATERIALS AND METHODS: From June 1998 to November 2001, 35 patients were submitted to conformal radiotherapy for PSA > 0.2 ng/mL in progression after radical prostatectomy and were retrospectively analyzed. The mean dose of radiation in prostatic bed was of 77.4 Gy (68-81. Variables related to the treatment and to tumor were assessed to identify prognostic factors for biochemical recurrence after salvage radiotherapy. RESULTS: The median follow-up was of 55 months (17-83. The actuarial survival rates free of biochemical recurrence and free of metastasis at a distance of 5 years were 79.7% e 84.7%, respectively. The actuarial global survival rate in 5 years was 96.1%.The actuarial survival rate free of biochemical recurrence in 5 years was 83.3% with PSA pre-radiotherapy 1 and 2 (p = 0.023. Dose > 70 Gy in 30% of the bladder volume implied in more acute urinary toxicity (p = 0.035. The mean time for the development of late urinary toxicity was 21 months (12-51. Dose > 55 Gy in 50% bladder volume implied in more late urinary toxicity (p = 0.018. A patient presented late rectal toxicity of 2nd grade. CONCLUSIONS: Conformal radiotherapy showed to be effective for the control of biochemical recurrence after radical prostatectomy. Patients with pre-therapy PSA < 2 ng/mL have more biochemical control.

  15. A Novel Method Using Abstract Convex Underestimation in Ab-Initio Protein Structure Prediction for Guiding Search in Conformational Feature Space.

    Science.gov (United States)

    Hao, Xiao-Hu; Zhang, Gui-Jun; Zhou, Xiao-Gen; Yu, Xu-Feng

    2016-01-01

    To address the searching problem of protein conformational space in ab-initio protein structure prediction, a novel method using abstract convex underestimation (ACUE) based on the framework of evolutionary algorithm was proposed. Computing such conformations, essential to associate structural and functional information with gene sequences, is challenging due to the high-dimensionality and rugged energy surface of the protein conformational space. As a consequence, the dimension of protein conformational space should be reduced to a proper level. In this paper, the high-dimensionality original conformational space was converted into feature space whose dimension is considerably reduced by feature extraction technique. And, the underestimate space could be constructed according to abstract convex theory. Thus, the entropy effect caused by searching in the high-dimensionality conformational space could be avoided through such conversion. The tight lower bound estimate information was obtained to guide the searching direction, and the invalid searching area in which the global optimal solution is not located could be eliminated in advance. Moreover, instead of expensively calculating the energy of conformations in the original conformational space, the estimate value is employed to judge if the conformation is worth exploring to reduce the evaluation time, thereby making computational cost lower and the searching process more efficient. Additionally, fragment assembly and the Monte Carlo method are combined to generate a series of metastable conformations by sampling in the conformational space. The proposed method provides a novel technique to solve the searching problem of protein conformational space. Twenty small-to-medium structurally diverse proteins were tested, and the proposed ACUE method was compared with It Fix, HEA, Rosetta and the developed method LEDE without underestimate information. Test results show that the ACUE method can more rapidly and more

  16. CT-image based conformal brachytherapy of breast cancer. The significance of semi-3-D and 3-D treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Polgar, C.; Major, T.; Somogyi, A.; Takacsi-Nagy, Z.; Mangel, L.C.; Fodor, J.; Nemeth, G. [Orszagos Onkologiai Intezet, Budapest (Hungary). Dept. of Radiotherapy; Forrai, G. [Haynal Imre Univ. of Health Sciences, Budapest (Hungary). Dept. of Radiology; Sulyok, Z. [Orszagos Onkologiai Intezet, Budapest (Hungary). Dept. of Surgery

    2000-03-01

    In 103 patients with T1-2, N0-1 breast cancer the tumor bed was clipped during breast conserving surgery. Fifty-two of them received boost brachytherapy after 46 to 50 Gy teletherapy and 51 patients were treated with brachytherapy alone via flexible implant tubes. Single double and triple plane implant was used in 6,89 and 8 cases, respectively. The dose of boost brachytherapy and sole brachytherapy prescribed to dose reference points was 3 times 4.75 Gy and 7 times 5.2 Gy, respectively. The positions of dose reference points varied according to the level (2-D, semi-3-D and 3-D) of treatment planning performed. The treatment planning was based on the 3-D reconstruction of the surgical clips, implant tubes and skin points. In all cases the implantations were planned with a semi-3-D technique aided by simulator. In 10 cases a recently developed CT-guided 3-D planning system was used. The semi-3D and 3-D treatment plans were compared to hypothetical 2-D plans using dose-volume histograms and dose non-uniformity ratios. The values of mean central dose, mean skin dose, minimal clip dose, proportion of underdosaged clips and mean target surface dose were evaluated. The accuracy of tumor bed localization and the conformity of planning target volume and treated volume were also analyzed in each technique. Results: With the help of conformal semi-3D and 3D brachytherapy planning we could define reference dose points, active source positions and dwell times individually. This technique decreased the mean skin dose with 22.2% and reduced the possibility of geographical miss. We could achieve the best conformity between the planning target volume and the treated volume with the CT-image based 3-D treatment planning, at the cost of worse dose homogeneity. The mean treated volume was reduced by 25.1% with semi-3-D planning, however, its was increased by 16.2% with 3-D planning, compared to the 2-D planning. (orig.) [German] Bei 103 Patientinnen mit Mammakarzinom der Stadien T1

  17. Conformational Analysis of Contrast Media for X-Ray Diagnostic Radiology

    International Nuclear Information System (INIS)

    Solieman, A.H.M.

    2010-01-01

    The conformational analysis of iodinated non-ionic contrast agent, Iobitridol, was carried out using theoretical calculations to explore its conformational space, and to study different aspects connected with application of different search techniques. Monte Carlo (MC), random search (RS) and molecular dynamics (MD) based conformational search techniques were used to extract a reasonable-size sample that adequately represents and has an average behavior of the entire conformational ensemble.While MC is good for quick search for lowest energy conformer, RS is better in obtaining conformational sample that cover the whole conformational space and MD is the best for investigation of isomeric preferences inside the conformational ensemble at thermal equilibrium. Conformational analysis of the produced gas phase samples reveals that RS and MD methods could sufficiently present the 18 distinct isomeric classes that constitute the total conformational space of the Iobitridol. S samples of conformational space of Iobitridol are extensively studied, as it hypothetically cover the total conformational space. They are used to test the suitability of different methods (charge distribution methods, energy calculation methods) for Iobitridol molecular computations and internal structure forces (steric hindrance, resonance interaction), as well as dependences among the internal coordinates (dihedral angles correlations and coincidences). The atomic partial charge distribution is found to greatly affect the energy calculation for the molecular mechanics based conformational energy distributions. Further energy minimization of conformational sample by the quantum molecular orbital methods is crucial to obtain charge independent as well as energy balanced conformational sample.

  18. Analysis of the efficacy and safety of conventional radiotherapy of chest wall and clavicular field and three-dimensional conformal radiotherapy in patients after modified radical mastectomy

    Directory of Open Access Journals (Sweden)

    Song-Lin Wang

    2017-04-01

    Full Text Available Objective: To explore the efficacy and safety of conventional radiotherapy of chest wall and clavicular field and three-dimensional conformal radiotherapy in patients after modified radical mastectomy. Methods: A total of 84 patients who were admitted in our hospital after modified radical mastectomy were included in the study and divided into the conventional radiotherapy group (n=42 and the three-dimensional conformal radiotherapy group (n=42 according to different radiotherapy methods. The patients in the conventional radiotherapy group were given conventional radiotherapy of chest wall and clavicular field, while the patients in the three-dimensional conformal radiotherapy group were given three-dimensional conformal radiotherapy. The serum tumor markers and peripheral blood T lymphocyte subsets 6-8 weeks after treatment in the two groups were detected. The clinical efficacy, and toxic and side effects in the two groups were evaluated. Results: The serum CA15-3, CA125, CEA, and CK19 levels after treatment in the two groups were significantly reduced when compared with before treatment, CD3 +,CD4 +, and CD4 +/CD8 + were significantly elevated, while CD8 + was significantly reduced when compared with before treatment, but the comparison of the above indicators between the two groups was not statistically significant. The occurrence rate of radioactive skin damage and pneumonia after treatment in the conventional radiotherapy group was significantly higher than that in the three-dimensional conformal radiotherapy group. Conclusions: The two kinds of radiotherapy schemes have an equal efficacy, but the toxic and side effects of three-dimensional conformal radiotherapy are significantly lower than those by the conventional radiotherapy, with a certain advantage.

  19. Effects of Catalytic Action and Ligand Binding on Conformational Ensembles of Adenylate Kinase.

    Science.gov (United States)

    Onuk, Emre; Badger, John; Wang, Yu Jing; Bardhan, Jaydeep; Chishti, Yasmin; Akcakaya, Murat; Brooks, Dana H; Erdogmus, Deniz; Minh, David D L; Makowski, Lee

    2017-08-29

    Crystal structures of adenylate kinase (AdK) from Escherichia coli capture two states: an "open" conformation (apo) obtained in the absence of ligands and a "closed" conformation in which ligands are bound. Other AdK crystal structures suggest intermediate conformations that may lie on the transition pathway between these two states. To characterize the transition from open to closed states in solution, X-ray solution scattering data were collected from AdK in the apo form and with progressively increasing concentrations of five different ligands. Scattering data from apo AdK are consistent with scattering predicted from the crystal structure of AdK in the open conformation. In contrast, data from AdK samples saturated with Ap5A do not agree with that calculated from AdK in the closed conformation. Using cluster analysis of available structures, we selected representative structures in five conformational states: open, partially open, intermediate, partially closed, and closed. We used these structures to estimate the relative abundances of these states for each experimental condition. X-ray solution scattering data obtained from AdK with AMP are dominated by scattering from AdK in the open conformation. For AdK in the presence of high concentrations of ATP and ADP, the conformational ensemble shifts to a mixture of partially open and closed states. Even when AdK is saturated with Ap5A, a significant proportion of AdK remains in a partially open conformation. These results are consistent with an induced-fit model in which the transition of AdK from an open state to a closed state is initiated by ATP binding.

  20. Static validation of licence conformance policies

    DEFF Research Database (Denmark)

    Hansen, Rene Rydhof; Nielson, Flemming; Nielson, Hanne Riis

    2008-01-01

    Policy conformance is a security property gaining importance due to commercial interest like Digital Rights Management. It is well known that static analysis can be used to validate a number of more classical security policies, such as discretionary and mandatory access control policies, as well...... as communication protocols using symmetric and asymmetric cryptography. In this work we show how to develop a Flow Logic for validating the conformance of client software with respect to a licence conformance policy. Our approach is sufficiently flexible that it extends to fully open systems that can admit new...

  1. The decomposition of global conformal invariants

    CERN Document Server

    Alexakis, Spyros

    2012-01-01

    This book addresses a basic question in differential geometry that was first considered by physicists Stanley Deser and Adam Schwimmer in 1993 in their study of conformal anomalies. The question concerns conformally invariant functionals on the space of Riemannian metrics over a given manifold. These functionals act on a metric by first constructing a Riemannian scalar out of it, and then integrating this scalar over the manifold. Suppose this integral remains invariant under conformal re-scalings of the underlying metric. What information can one then deduce about the Riemannian scalar? Dese

  2. Lithium Sulfide (Li2S)/Graphene Oxide Nanospheres with Conformal Carbon Coating as a High-Rate, Long-Life Cathode for Li/S Cells.

    Science.gov (United States)

    Hwa, Yoon; Zhao, Juan; Cairns, Elton J

    2015-05-13

    In recent years, lithium/sulfur (Li/S) cells have attracted great attention as a candidate for the next generation of rechargeable batteries due to their high theoretical specific energy of 2600 W·h kg(-1), which is much higher than that of Li ion cells (400-600 W·h kg(-1)). However, problems of the S cathode such as highly soluble intermediate species (polysulfides Li2Sn, n = 4-8) and the insulating nature of S cause poor cycle life and low utilization of S, which prevents the practical use of Li/S cells. Here, a high-rate and long-life Li/S cell is proposed, which has a cathode material with a core-shell nanostructure comprising Li2S nanospheres with an embedded graphene oxide (GO) sheet as a core material and a conformal carbon layer as a shell. The conformal carbon coating is easily obtained by a unique CVD coating process using a lab-designed rotating furnace without any repetitive steps. The Li2S/GO@C cathode exhibits a high initial discharge capacity of 650 mA·h g(-1) of Li2S (corresponding to the 942 mA·h g(-1) of S) and very low capacity decay rate of only 0.046% per cycle with a high Coulombic efficiency of up to 99.7% for 1500 cycles when cycled at the 2 C discharge rate.

  3. Towards multidimensional radiotherapy (MD-CRT): biological imaging and biological conformality

    International Nuclear Information System (INIS)

    Ling, C. Clifton; Humm, John; Larson, Steven; Amols, Howard; Fuks, Zvi; Leibel, Steven; Koutcher, Jason A.

    2000-01-01

    Purpose: The goals of this study were to survey and summarize the advances in imaging that have potential applications in radiation oncology, and to explore the concept of integrating physical and biological conformality in multidimensional conformal radiotherapy (MD-CRT). Methods and Materials: The advances in three-dimensional conformal radiotherapy (3D-CRT) have greatly improved the physical conformality of treatment planning and delivery. The development of intensity-modulated radiotherapy (IMRT) has provided the 'dose painting' or 'dose sculpting' ability to further customize the delivered dose distribution. The improved capabilities of nuclear magnetic resonance imaging and spectroscopy, and of positron emission tomography, are beginning to provide physiological and functional information about the tumor and its surroundings. In addition, molecular imaging promises to reveal tumor biology at the genotype and phenotype level. These developments converge to provide significant opportunities for enhancing the success of radiotherapy. Results: The ability of IMRT to deliver nonuniform dose patterns by design brings to fore the question of how to 'dose paint' and 'dose sculpt', leading to the suggestion that 'biological' images may be of assistance. In contrast to the conventional radiological images that primarily provide anatomical information, biological images reveal metabolic, functional, physiological, genotypic, and phenotypic data. Important for radiotherapy, the new and noninvasive imaging methods may yield three-dimensional radiobiological information. Studies are urgently needed to identify genotypes and phenotypes that affect radiosensitivity, and to devise methods to image them noninvasively. Incremental to the concept of gross, clinical, and planning target volumes (GTV, CTV, and PTV), we propose the concept of 'biological target volume' (BTV) and hypothesize that BTV can be derived from biological images and that their use may incrementally improve

  4. 77 FR 14979 - Transportation Conformity Rule Restructuring Amendments

    Science.gov (United States)

    2012-03-14

    ... Transportation Conformity Rule Restructuring Amendments AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is amending the transportation conformity rule to finalize provisions that were proposed on August 13, 2010. These amendments restructure several sections of the transportation conformity...

  5. Solid state conformational classification of eight-membered rings

    DEFF Research Database (Denmark)

    Pérez, J.; García, L.; Kessler, M.

    2005-01-01

    A statistical classification of the solid state conformation in the title complexes using data retrieved from the Cambridge Structural Database (CSD) has been made. Phosphate and phosphinate complexes show a chair conformation preferably. In phosphonate complexes, the most frequent conformations...

  6. Conformity of package inserts information to regulatory requirements among selected branded and generic medicinal products circulating on the East African market.

    Science.gov (United States)

    Sillo, Hiiti B; Masota, Nelson E; Kisoma, Sunday; Rago, Lembit; Mgoyela, Veronica; Kaale, Eliangiringa A

    2018-01-01

    Availability of correct and adequate information about medicines is an important aspect in ensuring rational use of medicines and hence facilitating safety and expected efficacy of medicines during therapy. Package inserts have proven to be a good source of information to the prescribers and patients whereby they have been useful in highlighting important information pertaining proper use and handling of the medicines. The present study was aimed at establishing the extent to which package inserts of medicines circulating on the markets of the East African Community (EAC) Partner States conform to medicines information requirements as established in the harmonized guidelines as well as national guidelines. A total of 99 package inserts from six (6) types of medicines namely Albendazole, Artemether/Lumefantrine (ALu), Ciprofloxacin, Paracetamol, Amoxicillin and Metronidazole were purposefully collected from three EAC Partner States: Kenya, Tanzania and Uganda. The medicines were selected based on their indications as first line treatments, high rates of utilization within the medicines supply system and their positions in treatment of diseases of public importance across EAC Partner States. The inserts were evaluated on the availability of information regarding fifteen (15) parameters as extracted from the EAC harmonized guidelines for registration of medicines. Moreover, comparisons were made between the percentage conformity of the branded versus generic products, markets from which the samples were collected, origin of the manufacturer and type of medicine. Majority (93.9-100%) of the medicines' package inserts highly conformed to the inclusion of the information regarding the description and composition of the medications, indications, dosage and methods of administration, warnings and precautions, contraindications and storage conditions. However, the information on handling and disposal, container package description, excipients used, clinical pharmacology of

  7. Revision of orthovoltage chest wall treatment using Monte Carlo simulations.

    Science.gov (United States)

    Zeinali-Rafsanjani, B; Faghihi, R; Mosleh-Shirazi, M A; Mosalaei, A; Hadad, K

    2017-01-01

    Given the high local control rates observed in breast cancer patients undergoing chest wall irradiation by kilovoltage x-rays, we aimed to revisit this treatment modality by accurate calculation of dose distributions using Monte Carlo simulation. The machine components were simulated using the MCNPX code. This model was used to assess the dose distribution of chest wall kilovoltage treatment in different chest wall thicknesses and larger contour or fat patients in standard and mid sternum treatment plans. Assessments were performed at 50 and 100 cm focus surface distance (FSD) and different irradiation angles. In order to evaluate different plans, indices like homogeneity index, conformity index, the average dose of heart, lung, left anterior descending artery (LAD) and percentage target coverage (PTC) were used. Finally, the results were compared with the indices provided by electron therapy which is a more routine treatment of chest wall. These indices in a medium chest wall thickness in standard treatment plan at 50 cm FSD and 15 degrees tube angle was as follows: homogeneity index 2.57, conformity index 7.31, average target dose 27.43 Gy, average dose of heart, lung and LAD, 1.03, 2.08 and 1.60 Gy respectively and PTC 11.19%. Assessments revealed that dose homogeneity in planning target volume (PTV) and conformity between the high dose region and PTV was poor. To improve the treatment indices, the reference point was transferred from the chest wall skin surface to the center of PTV. The indices changed as follows: conformity index 7.31, average target dose 60.19 Gy, the average dose of heart, lung and LAD, 3.57, 6.38 and 5.05 Gy respectively and PTC 55.24%. Coverage index of electron therapy was 89% while it was 22.74% in the old orthovoltage method and also the average dose of the target was about 50 Gy but in the given method it was almost 30 Gy. The results of the treatment study show that the optimized standard and mid sternum treatment for different chest

  8. Application of Conformational Space Search in Drug Action | Adikwu ...

    African Journals Online (AJOL)

    The role of conformational space in drug action is presented. Two examples of molecules in different therapeutic groups are presented. Conformational space search will lead to isolating the exact conformation with the desired medicinal properties. Many conformations of a plant isolate may exist which are active, weakly ...

  9. Defects in conformal field theory

    International Nuclear Information System (INIS)

    Billò, Marco; Gonçalves, Vasco; Lauria, Edoardo; Meineri, Marco

    2016-01-01

    We discuss consequences of the breaking of conformal symmetry by a flat or spherical extended operator. We adapt the embedding formalism to the study of correlation functions of symmetric traceless tensors in the presence of the defect. Two-point functions of a bulk and a defect primary are fixed by conformal invariance up to a set of OPE coefficients, and we identify the allowed tensor structures. A correlator of two bulk primaries depends on two cross-ratios, and we study its conformal block decomposition in the case of external scalars. The Casimir equation in the defect channel reduces to a hypergeometric equation, while the bulk channel blocks are recursively determined in the light-cone limit. In the special case of a defect of codimension two, we map the Casimir equation in the bulk channel to the one of a four-point function without defect. Finally, we analyze the contact terms of the stress-tensor with the extended operator, and we deduce constraints on the CFT data. In two dimensions, we relate the displacement operator, which appears among the contact terms, to the reflection coefficient of a conformal interface, and we find unitarity bounds for the latter.

  10. Defects in conformal field theory

    Energy Technology Data Exchange (ETDEWEB)

    Billò, Marco [Dipartimento di Fisica, Università di Torino, and Istituto Nazionale di Fisica Nucleare - sezione di Torino,Via P. Giuria 1 I-10125 Torino (Italy); Gonçalves, Vasco [Centro de Física do Porto,Departamento de Física e Astronomia Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); ICTP South American Institute for Fundamental Research Instituto de Física Teórica,UNESP - University Estadual Paulista,Rua Dr. Bento T. Ferraz 271, 01140-070, São Paulo, SP (Brazil); Lauria, Edoardo [Institute for Theoretical Physics, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Meineri, Marco [Perimeter Institute for Theoretical Physics,Waterloo, Ontario, N2L 2Y5 (Canada); Scuola Normale Superiore, and Istituto Nazionale di Fisica Nucleare - sezione di Pisa,Piazza dei Cavalieri 7 I-56126 Pisa (Italy)

    2016-04-15

    We discuss consequences of the breaking of conformal symmetry by a flat or spherical extended operator. We adapt the embedding formalism to the study of correlation functions of symmetric traceless tensors in the presence of the defect. Two-point functions of a bulk and a defect primary are fixed by conformal invariance up to a set of OPE coefficients, and we identify the allowed tensor structures. A correlator of two bulk primaries depends on two cross-ratios, and we study its conformal block decomposition in the case of external scalars. The Casimir equation in the defect channel reduces to a hypergeometric equation, while the bulk channel blocks are recursively determined in the light-cone limit. In the special case of a defect of codimension two, we map the Casimir equation in the bulk channel to the one of a four-point function without defect. Finally, we analyze the contact terms of the stress-tensor with the extended operator, and we deduce constraints on the CFT data. In two dimensions, we relate the displacement operator, which appears among the contact terms, to the reflection coefficient of a conformal interface, and we find unitarity bounds for the latter.

  11. Relationship between Oversulfation and Conformation of Low and High Molecular Weight Fucoidans and Evaluation of Their in Vitro Anticancer Activity

    Directory of Open Access Journals (Sweden)

    Myoung Lae Cho

    2010-12-01

    Full Text Available Low and high molecular weight fucoidans (F5-30K and F>30K were chemically modified through the addition of sulfate groups, and the effect of oversulfation on the in vitro anticancer activity was investigated. After the addition of sulfate groups, a considerable increase of 35.5 to 56.8% was observed in the sulfate content of the F5-30K fraction, while the sulfate content of the F>30K fraction increased to a lesser extent (from 31.7 to 41.2%. Significant differences in anticancer activity were observed between the oversulfated F5–30K and F>30K fractions, with activities of 37.3–68.0% and 20.6–35.8%, respectively. This variation in the anticancer activity of oversulfated fucoidan derivatives was likely due to differences in their sulfate content. The results suggest that the molecular conformation of these molecules is closely related to the extent of sulfation in the fucan backbones and that the sulfates are preferably substituted when the fucoidan polymers are in a loose molecular conformation.

  12. UV conformal window for asymptotic safety

    Science.gov (United States)

    Bond, Andrew D.; Litim, Daniel F.; Vazquez, Gustavo Medina; Steudtner, Tom

    2018-02-01

    Interacting fixed points in four-dimensional gauge theories coupled to matter are investigated using perturbation theory up to three loop order. It is shown how fixed points, scaling exponents, and anomalous dimensions are obtained as a systematic power series in a small parameter. The underlying ordering principle is explained and contrasted with conventional perturbation theory and Weyl consistency conditions. We then determine the conformal window with asymptotic safety from the complete next-to-next-to-leading order in perturbation theory. Limits for the conformal window arise due to fixed point mergers, the onset of strong coupling, or vacuum instability. A consistent picture is uncovered by comparing various levels of approximation. The theory remains perturbative in the entire conformal window, with vacuum stability dictating the tightest constraints. We also speculate about a secondary conformal window at strong coupling and estimate its lower limit. Implications for model building and cosmology are indicated.

  13. Synthesis of Conformal Phased Antenna Arrays With A Novel Multiobjective Invasive Weed Optimization Algorithm

    Science.gov (United States)

    Li, Wen Tao; Hei, Yong Qiang; Shi, Xiao Wei

    2018-04-01

    By virtue of the excellent aerodynamic performances, conformal phased arrays have been attracting considerable attention. However, for the synthesis of patterns with low/ultra-low sidelobes of the conventional conformal arrays, the obtained dynamic range ratios of amplitude excitations could be quite high, which results in stringent requirements on various error tolerances for practical implementation. Time-modulated array (TMA) has the advantages of low sidelobe and reduced dynamic range ratio requirement of amplitude excitations. This paper takes full advantages of conformal antenna arrays and time-modulated arrays. The active-element-pattern, including element mutual coupling and platform effects, is employed in the whole design process. To optimize the pulse durations and the switch-on instants of the time-modulated elements, multiobjective invasive weed optimization (MOIWO) algorithm based on the nondominated sorting of the solutions is proposed. A S-band 8-element cylindrical conformal array is designed and a S-band 16-element cylindrical-parabolic conformal array is constructed and tested at two different steering angles.

  14. Visualization of SV2A conformations in situ by the use of Protein Tomography

    International Nuclear Information System (INIS)

    Lynch, Berkley A.; Matagne, Alain; Braennstroem, Annika; Euler, Anne von; Jansson, Magnus; Hauzenberger, Elenor; Soederhaell, J. Arvid

    2008-01-01

    The synaptic vesicle protein 2A (SV2A), the brain-binding site of the anti-epileptic drug levetiracetam (LEV), has been characterized by Protein Tomography TM . We identified two major conformations of SV2A in mouse brain tissue: first, a compact, funnel-structure with a pore-like opening towards the cytoplasm; second, a more open, V-shaped structure with a cleft-like opening towards the intravesicular space. The large differences between these conformations suggest a high degree of flexibility and support a valve-like mechanism consistent with the postulated transporter role of SV2A. These two conformations are represented both in samples treated with LEV, and in saline-treated samples, which indicates that LEV binding does not cause a large-scale conformational change of SV2A, or lock a specific conformational state of the protein. This study provides the first direct structural data on SV2A, and supports a transporter function suggested by sequence homology to MFS class of transporter proteins

  15. Conformal coating by photoresist of sharp corners of anisotropically etched through-holes in silicon

    DEFF Research Database (Denmark)

    Heschel, Matthias; Bouwstra, Siebe

    1997-01-01

    The authors describe a photoresist treatment yielding conformal coating of three-dimensional silicon structures. This even includes the sharp corners of through-holes obtained by anisotropic etching in (100)-silicon. Resist reflow from these corners is avoided by replacing the common baking...

  16. Irregular conformal block, spectral curve and flow equations

    International Nuclear Information System (INIS)

    Choi, Sang Kwan; Rim, Chaiho; Zhang, Hong

    2016-01-01

    Irregular conformal block is motivated by the Argyres-Douglas type of N=2 super conformal gauge theory. We investigate the classical/NS limit of irregular conformal block using the spectral curve on a Riemann surface with irregular punctures, which is equivalent to the loop equation of irregular matrix model. The spectral curve is reduced to the second order (Virasoro symmetry, SU(2) for the gauge theory) and third order (W_3 symmetry, SU(3)) differential equations of a polynomial with finite degree. The conformal and W symmetry generate the flow equations in the spectral curve and determine the irregular conformal block, hence the partition function of the Argyres-Douglas theory ala AGT conjecture.

  17. Scalar perturbations and conformal transformation

    International Nuclear Information System (INIS)

    Fabris, J.C.; Tossa, J.

    1995-11-01

    The non-minimal coupling of gravity to a scalar field can be transformed into a minimal coupling through a conformal transformation. We show how to connect the results of a perturbation calculation, performed around a Friedman-Robertson-Walker background solution, before and after the conformal transformation. We work in the synchronous gauge, but we discuss the implications of employing other frames. (author). 16 refs

  18. 49 CFR 577.9 - Conformity to statutory requirements.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Conformity to statutory requirements. 577.9 Section 577.9 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY... NOTIFICATION § 577.9 Conformity to statutory requirements. A notification that does not conform to the...

  19. 20 CFR 604.6 - Conformity and substantial compliance.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Conformity and substantial compliance. 604.6... FOR ELIGIBILITY FOR UNEMPLOYMENT COMPENSATION § 604.6 Conformity and substantial compliance. (a) In... for the administration of its UC program. (b) Resolving Issues of Conformity and Substantial...

  20. Vertex operator algebras and conformal field theory

    International Nuclear Information System (INIS)

    Huang, Y.Z.

    1992-01-01

    This paper discusses conformal field theory, an important physical theory, describing both two-dimensional critical phenomena in condensed matter physics and classical motions of strings in string theory. The study of conformal field theory will deepen the understanding of these theories and will help to understand string theory conceptually. Besides its importance in physics, the beautiful and rich mathematical structure of conformal field theory has interested many mathematicians. New relations between different branches of mathematics, such as representations of infinite-dimensional Lie algebras and Lie groups, Riemann surfaces and algebraic curves, the Monster sporadic group, modular functions and modular forms, elliptic genera and elliptic cohomology, Calabi-Yau manifolds, tensor categories, and knot theory, are revealed in the study of conformal field theory. It is therefore believed that the study of the mathematics involved in conformal field theory will ultimately lead to new mathematical structures which would be important to both mathematics and physics

  1. The butane condensed matter conformational problem

    NARCIS (Netherlands)

    Weber, A.C.J.; de Lange, C.A.; Meerts, W.L.; Burnell, E.E.

    2010-01-01

    From the dipolar couplings of orientationally ordered n-butane obtained by NMR spectroscopy we have calculated conformer probabilities using the modified Chord (Cd) and Size-and-Shape (CI) models to estimate the conformational dependence of the order matrix. All calculation methods make use of

  2. Conformal invariance and two-dimensional physics

    International Nuclear Information System (INIS)

    Zuber, J.B.

    1993-01-01

    Actually, physicists and mathematicians are very interested in conformal invariance: geometric transformations which keep angles. This symmetry is very important for two-dimensional systems as phase transitions, string theory or node mathematics. In this article, the author presents the conformal invariance and explains its usefulness

  3. Geometrical formulation of the conformal Ward identity

    International Nuclear Information System (INIS)

    Kachkachi, M.

    2002-08-01

    In this paper we use deep ideas in complex geometry that proved to be very powerful in unveiling the Polyakov measure on the moduli space of Riemann surfaces and lead to obtain the partition function of perturbative string theory for 2, 3, 4 loops. Indeed, a geometrical interpretation of the conformal Ward identity in two dimensional conformal field theory is proposed: the conformal anomaly is interpreted as a deformation of the complex structure of the basic Riemann surface. This point of view is in line with the modern trend of geometric quantizations that are based on deformations of classical structures. Then, we solve the conformal Ward identity by using this geometrical formalism. (author)

  4. Riemann monodromy problem and conformal field theories

    International Nuclear Information System (INIS)

    Blok, B.

    1989-01-01

    A systematic analysis of the use of the Riemann monodromy problem for determining correlators (conformal blocks) on the sphere is presented. The monodromy data is constructed in terms of the braid matrices and gives a constraint on the noninteger part of the conformal dimensions of the primary fields. To determine the conformal blocks we need to know the order of singularities. We establish a criterion which tells us when the knowledge of the conformal dimensions of primary fields suffice to determine the blocks. When zero modes of the extended algebra are present the analysis is more difficult. In this case we give a conjecture that works for the SU(2) WZW case. (orig.)

  5. Conformational analysis of g protein-coupled receptor signaling by hydrogen/deuterium exchange mass spectrometry.

    Science.gov (United States)

    Li, Sheng; Lee, Su Youn; Chung, Ka Young

    2015-01-01

    Conformational change and protein-protein interactions are two major mechanisms of membrane protein signal transduction, including G protein-coupled receptors (GPCRs). Upon agonist binding, GPCRs change conformation, resulting in interaction with downstream signaling molecules such as G proteins. To understand the precise signaling mechanism, studies have investigated the structural mechanism of GPCR signaling using X-ray crystallography, nuclear magnetic resonance (NMR), or electron paramagnetic resonance. In addition to these techniques, hydrogen/deuterium exchange mass spectrometry (HDX-MS) has recently been used in GPCR studies. HDX-MS measures the rate at which peptide amide hydrogens exchange with deuterium in the solvent. Exposed or flexible regions have higher exchange rates and excluded or ordered regions have lower exchange rates. Therefore, HDX-MS is a useful tool for studying protein-protein interfaces and conformational changes after protein activation or protein-protein interactions. Although HDX-MS does not give high-resolution structures, it analyzes protein conformations that are difficult to study with X-ray crystallography or NMR. Furthermore, conformational information from HDX-MS can help in the crystallization of X-ray crystallography by suggesting highly flexible regions. Interactions between GPCRs and downstream signaling molecules are not easily analyzed by X-ray crystallography or NMR because of the large size of the GPCR-signaling molecule complexes, hydrophobicity, and flexibility of GPCRs. HDX-MS could be useful for analyzing the conformational mechanism of GPCR signaling. In this chapter, we discuss details of HDX-MS for analyzing GPCRs using the β2AR-G protein complex as a model system. © 2015 Elsevier Inc. All rights reserved.

  6. The effects of information and social conformity on opinion change.

    Science.gov (United States)

    Mallinson, Daniel J; Hatemi, Peter K

    2018-01-01

    Extant research shows that social pressures influence acts of political participation, such as turning out to vote. However, we know less about how conformity pressures affect one's deeply held political values and opinions. Using a discussion-based experiment, we untangle the unique and combined effects of information and social pressure on a political opinion that is highly salient, politically charged, and part of one's identity. We find that while information plays a role in changing a person's opinion, the social delivery of that information has the greatest effect. Thirty three percent of individuals in our treatment condition change their opinion due to the social delivery of information, while ten percent respond only to social pressure and ten percent respond only to information. Participants that change their opinion due to social pressure in our experiment are more conservative politically, conscientious, and neurotic than those that did not.

  7. The effects of information and social conformity on opinion change

    Science.gov (United States)

    Hatemi, Peter K.

    2018-01-01

    Extant research shows that social pressures influence acts of political participation, such as turning out to vote. However, we know less about how conformity pressures affect one’s deeply held political values and opinions. Using a discussion-based experiment, we untangle the unique and combined effects of information and social pressure on a political opinion that is highly salient, politically charged, and part of one’s identity. We find that while information plays a role in changing a person’s opinion, the social delivery of that information has the greatest effect. Thirty three percent of individuals in our treatment condition change their opinion due to the social delivery of information, while ten percent respond only to social pressure and ten percent respond only to information. Participants that change their opinion due to social pressure in our experiment are more conservative politically, conscientious, and neurotic than those that did not. PMID:29718958

  8. HIV p24 as scaffold for presenting conformational HIV Env antigens.

    Directory of Open Access Journals (Sweden)

    Maria Tagliamonte

    Full Text Available Heterologous protein scaffolds engrafted with structurally defined HIV Env epitopes recognized by broadly neutralizing monoclonal antibodies (MAbs represent a promising strategy to elicit broad neutralizing antibodies. In such regards, a protein scaffold based on the HIV p24 CA protein is a highly attractive approach, providing also Gag epitopes for eliciting HIV non-neutralizing protective antibodies and specific CD4(+ and CD8(+ T cell responses. In the present study, computational techniques were employed to verify the presence of acceptor sites for conformational HIV Env epitopes and, as proof of concept, the analysis of HIV p24 CA-based scaffolds using a complete V3 loop in a MAb-bound conformation is presented. The V3-p24 epitope-scaffold proteins show the formation of capsomers made of hexamers similarly to the p24 wild type protein. Moreover, the conformational V3 loop presented on p24 scaffold is recognized by a panel of anti-V3 MAbs. The results suggest that HIV p24 CA protein has suitable acceptor sites for engrafting foreign epitopes, without disrupting the formation of capsomer hexamer structures, and that the V3 epitope does retain its antibody-bound conformation. This strongly support the feasibility of developing a scaffolding strategy based on p24 CA proteins displaying conformational minimal structural, antigenic HIV Env epitopes.

  9. Conformational Dynamics of the Receptor Protein Galactose/Glucose Binding Protein

    Science.gov (United States)

    Messina, Troy; Talaga, David

    2006-03-01

    We have performed time-correlated single photon counting (TCSPC) anisotropy and Stokes Shift measurements on bulk solutions of galactose/glucose binding protein. Site-directed mutagenesis was used to provide a single cysteine amino acid near the sugar-binding center of the protein (glutamine 26 to cysteine -- Q26C). The cysteine was covalently labeled with the environmentally-sensitive fluorophore acrylodan, and a long-lived ruthenium complex was covalently attached to the N-terminus to provide a fluorescent reference. The TCSPC data were analyzed using global convolute-and-compare fitting routines over the entire glucose titration and temperature range to provide minimal reduced chi-squared values and the highest time resolution possible. Using a standard ligand-binding model, the resulting distributions show that the closed (ligand-bound) conformation exists even at zero glucose concentration. At 20^oC, the relative abundance of this conformation is as high as 40%. The temperature dependence of this conformational study will be discussed and related to the ligand-binding free energy surface.

  10. Conformal field theories and tensor categories. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Chengming [Nankai Univ., Tianjin (China). Chern Institute of Mathematics; Fuchs, Juergen [Karlstad Univ. (Sweden). Theoretical Physics; Huang, Yi-Zhi [Rutgers Univ., Piscataway, NJ (United States). Dept. of Mathematics; Kong, Liang [Tsinghua Univ., Beijing (China). Inst. for Advanced Study; Runkel, Ingo; Schweigert, Christoph (eds.) [Hamburg Univ. (Germany). Dept. of Mathematics

    2014-08-01

    First book devoted completely to the mathematics of conformal field theories, tensor categories and their applications. Contributors include both mathematicians and physicists. Some long expository articles are especially suitable for beginners. The present volume is a collection of seven papers that are either based on the talks presented at the workshop ''Conformal field theories and tensor categories'' held June 13 to June 17, 2011 at the Beijing International Center for Mathematical Research, Peking University, or are extensions of the material presented in the talks at the workshop. These papers present new developments beyond rational conformal field theories and modular tensor categories and new applications in mathematics and physics. The topics covered include tensor categories from representation categories of Hopf algebras, applications of conformal field theories and tensor categories to topological phases and gapped systems, logarithmic conformal field theories and the corresponding non-semisimple tensor categories, and new developments in the representation theory of vertex operator algebras. Some of the papers contain detailed introductory material that is helpful for graduate students and researchers looking for an introduction to these research directions. The papers also discuss exciting recent developments in the area of conformal field theories, tensor categories and their applications and will be extremely useful for researchers working in these areas.

  11. Conformal field theories and tensor categories. Proceedings

    International Nuclear Information System (INIS)

    Bai, Chengming; Fuchs, Juergen; Huang, Yi-Zhi; Kong, Liang; Runkel, Ingo; Schweigert, Christoph

    2014-01-01

    First book devoted completely to the mathematics of conformal field theories, tensor categories and their applications. Contributors include both mathematicians and physicists. Some long expository articles are especially suitable for beginners. The present volume is a collection of seven papers that are either based on the talks presented at the workshop ''Conformal field theories and tensor categories'' held June 13 to June 17, 2011 at the Beijing International Center for Mathematical Research, Peking University, or are extensions of the material presented in the talks at the workshop. These papers present new developments beyond rational conformal field theories and modular tensor categories and new applications in mathematics and physics. The topics covered include tensor categories from representation categories of Hopf algebras, applications of conformal field theories and tensor categories to topological phases and gapped systems, logarithmic conformal field theories and the corresponding non-semisimple tensor categories, and new developments in the representation theory of vertex operator algebras. Some of the papers contain detailed introductory material that is helpful for graduate students and researchers looking for an introduction to these research directions. The papers also discuss exciting recent developments in the area of conformal field theories, tensor categories and their applications and will be extremely useful for researchers working in these areas.

  12. Clinical treatment planning optimization by Powell's method for gamma unit treatment system

    International Nuclear Information System (INIS)

    Yan Yulong; Shu Huazhong; Bao Xudong; Luo Limin; Bai Yi

    1997-01-01

    Purpose: This article presents a new optimization method for stereotactic radiosurgery treatment planning for gamma unit treatment system. Methods and Materials: The gamma unit has been utilized in stereotactic radiosurgery for about 30 years, but the usual procedure for a physician-physicist team to design a treatment plan is a trial-and-error approach. Isodose curves are viewed on two-dimensional computed tomography (CT) or magnetic resonance (MR) image planes, which is not only time consuming but also seldom achieves the optimal treatment plan, especially when the isocenter weights are regarded. We developed a treatment-planning system on a computer workstation in which Powell's optimization method is realized. The optimization process starts with the initial parameters (the number of iso centers as well as corresponding 3D iso centers' coordinates, collimator sizes, and weight factors) roughly determined by the physician-physicist team. The objective function can be changed to consider protection of sensitive tissues. Results: We use the plan parameters given by a well-trained physician-physicist team, or ones that the author give roughly as the initial parameters for the optimization procedure. Dosimetric results of optimization show a better high dose-volume conformation to the target volume compared to the doctor's plan. Conclusion: This method converges quickly and is not sensitive to the initial parameters. It achieves an excellent conformation of the estimated isodose curves with the contours of the target volume. If the initial parameters are varied, there will be a little difference in parameters' configuration, but the dosimetric results proved almost to be the same

  13. Tolerance and early outcome results of postprostatectomy three-dimensional conformal radiotherapy

    International Nuclear Information System (INIS)

    Zelefsky, Michael J.; Aschkenasy, Eric; Kelsen, Suzanne; Leibel, Steven A.

    1997-01-01

    Purpose: Three-dimensional conformal radiotherapy (3D-CRT) has been associated with a reduction in acute and late toxicity among patients treated for localized prostatic cancer. The purpose of this study is to assess the acute and late toxicity of 3D-CRT delivered to patients in the postprostatectomy setting and to analyze which factors predict for durable biochemical control in this group of patients. Methods and Materials: Between 1988 and 1994, 42 patients were treated after prostatectomy with three-dimensional conformal radiotherapy. The median time from prostatectomy to radiotherapy was 11 months. Indications for treatment included a rising serum PSA level in 28 patients (65%) and positive surgical margins without a rising PSA level in 14 (35%). Twenty-five patients (60%) had pathologic stage T3 disease, and 32 (74%) had tumor at or close to the surgical margins. The median dose was 64.8 Gy, and the median follow-up time was 2 years. Results: 3D-CRT in the postprostatectomy setting was well tolerated. Three patients (7%) experienced Grade II acute genitourinary toxicity and nine patients (21%) experienced Grade II acute gastrointestinal toxicity during treatment. No patient experienced Grade III or higher acute morbidity. The 2-year actuarial risk for Grade II late genitourinary and gastrointestinal late complications were 5 and 9%, respectively. In patients with existing incontinence, the incidence of worsening stress incontinence 6 months after treatment was 17%, which resolved within 12 months to its preradiotherapy level in four of six cases (66%). The overall 2-year postirradiation PSA relapse-free survival rate was 53%. The 2-year PSA relapse-free survival was 66% for patients with undetectable PSA levels in the immediate postoperative period compared to 26% for those with detectable levels of PSA after surgery (p 1.0 ng/ml (p 1 ng/ml (p < 0.002) was the most important covariate predicting for a rising PSA after radiotherapy. Conclusions: After

  14. Conformal anomaly actions for dilaton interactions

    Directory of Open Access Journals (Sweden)

    Rose Luigi Delle

    2014-01-01

    Full Text Available We discuss, in conformally invariant field theories such as QCD with massless fermions, a possible link between the perturbative signature of the conformal anomaly, in the form of anomaly poles of the 1-particle irreducible effective action, and its descrip- tion in terms of Wess-Zumino actions with a dilaton. The two descriptions are expected to capture the UV and IR behaviour of the conformal anomaly, in terms of fundamental and effective degrees of freedom respectively, with the dilaton effective state appearing in a nonlinear realization. As in the chiral case, conformal anomalies seem to be related to the appearance of these effective interactions in the 1PI action in all the gauge-invariant sectors of the Standard Model. We show that, as a consequence of the underlying anomalous symmetry, the infinite hierarchy of recurrence relations involving self-interactions of the dilaton is entirely determined only by the first four of them. This relation can be generalized to any even space-time dimension.

  15. Invariants for minimal conformal supergravity in six dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Butter, Daniel [Nikhef Theory Group,Science Park 105, 1098 XG Amsterdam (Netherlands); Kuzenko, Sergei M. [School of Physics M013, The University of Western Australia,35 Stirling Highway, Crawley W.A. 6009 (Australia); Novak, Joseph; Theisen, Stefan [Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut,Am Mühlenberg 1, D-14476 Golm (Germany)

    2016-12-15

    We develop a new off-shell formulation for six-dimensional conformal supergravity obtained by gauging the 6D N=(1,0) superconformal algebra in superspace. This formulation is employed to construct two invariants for 6D N=(1,0) conformal supergravity, which contain C{sup 3} and C◻C terms at the component level. Using a conformal supercurrent analysis, we prove that these exhaust all such invariants in minimal conformal supergravity. Finally, we show how to construct the supersymmetric F◻F invariant in curved superspace.

  16. Nasopharynx carcinoma treatment: from the conventional radiotherapy to the conformal radiotherapy with intensity modulation; Traitement du carcinome du nasopharynx: de la radiotherapie conventionnelle a la radiotherapie conformationnelle avec modulation d'intensite

    Energy Technology Data Exchange (ETDEWEB)

    Mokaouim, K.; Grehange, G.; Truc, G.; Peingnaux, K.; Martin, E.; Zanetta, S.; Bruchon, Y.; Bonnetain, F.; Maingon, P. [Centre Georges-Francois Leclerc, 21 - Dijon (France)

    2009-10-15

    The objective of this study was to evaluate retrospectively the impact of factors linked to the radiotherapy realisation on the local and locoregional control, the global survival, the survival without disease of patients suffering of naso-pharynx carcinoma. Conclusion: the patients suffering of a nasopharynx carcinoma treated by irradiation associated to chemotherapy have an improved global survival and an improved survival without disease. The conformal radiotherapy with or without modulated intensity reduce the risk of serous otitis, trismus and xerostomia at long term. It seems necessary to realize multi centric studies with a longer period of follow up before asserting the advantages of the I.M.R.T. in comparison to the classical and conformal technique in the treatment of naso-pharynx carcinomas. (N.C.)

  17. A conformational switch high-throughput screening assay and allosteric inhibition of the flavivirus NS2B-NS3 protease.

    Directory of Open Access Journals (Sweden)

    Matthew Brecher

    2017-05-01

    Full Text Available The flavivirus genome encodes a single polyprotein precursor requiring multiple cleavages by host and viral proteases in order to produce the individual proteins that constitute an infectious virion. Previous studies have revealed that the NS2B cofactor of the viral NS2B-NS3 heterocomplex protease displays a conformational dynamic between active and inactive states. Here, we developed a conformational switch assay based on split luciferase complementation (SLC to monitor the conformational change of NS2B and to characterize candidate allosteric inhibitors. Binding of an active-site inhibitor to the protease resulted in a conformational change of NS2B and led to significant SLC enhancement. Mutagenesis of key residues at an allosteric site abolished this induced conformational change and SLC enhancement. We also performed a virtual screen of NCI library compounds to identify allosteric inhibitors, followed by in vitro biochemical screening of the resultant candidates. Only three of these compounds, NSC135618, 260594, and 146771, significantly inhibited the protease of Dengue virus 2 (DENV2 in vitro, with IC50 values of 1.8 μM, 11.4 μM, and 4.8 μM, respectively. Among the three compounds, only NSC135618 significantly suppressed the SLC enhancement triggered by binding of active-site inhibitor in a dose-dependent manner, indicating that it inhibits the conformational change of NS2B. Results from virus titer reduction assays revealed that NSC135618 is a broad spectrum flavivirus protease inhibitor, and can significantly reduce titers of DENV2, Zika virus (ZIKV, West Nile virus (WNV, and Yellow fever virus (YFV on A549 cells in vivo, with EC50 values in low micromolar range. In contrast, the cytotoxicity of NSC135618 is only moderate with CC50 of 48.8 μM on A549 cells. Moreover, NSC135618 inhibited ZIKV in human placental and neural progenitor cells relevant to ZIKV pathogenesis. Results from binding, kinetics, Western blot, mass spectrometry and

  18. A Mediated Moderation Model of Conformative Peer Bullying

    Science.gov (United States)

    Cho, Yoonju; Chung, Ock-Boon

    2012-01-01

    We investigated the relationship between conformative peer bullying and issues of peer conformity among adolescents. This relationship is examined through the establishment of a mediated moderation model for conformative peer bullying using structural equation modeling in a sample of 391 second-year middle school students in Seoul, South Korea. We…

  19. {kappa}-deformed realization of D=4 conformal algebra

    Energy Technology Data Exchange (ETDEWEB)

    Klimek, M. [Technical Univ. of Czestochowa, Inst. of Mathematics and Computer Science, Czestochowa (Poland); Lukierski, J. [Universite de Geneve, Department de Physique Theorique, Geneve (Switzerland)

    1995-07-01

    We describe the generators of {kappa}-conformal transformations, leaving invariant the {kappa}-deformed d`Alembert equation. In such a way one obtains the conformal extension of-shell spin spin zero realization of {kappa}-deformed Poincare algebra. Finally the algebraic structure of {kappa}-deformed conformal algebra is discussed. (author). 23 refs.

  20. Selective stimulation of conformational conversions in free molecules

    International Nuclear Information System (INIS)

    Ismailzade, G.I.; Movsumov, I.Z.; Menzeleev, M.R.; Kazymova, S.B.

    2014-01-01

    Application of double-resonance (RF-MW, IR-MW, MW-MW) methods to enhance studies of unstable isomeric structures was discussed. The use of infrared pump radiation to excite conformational energy levels in order to stimulate selectively conformational conversions and to correct spectral line intensities of separate conformations was substantiated. (authors)

  1. Driving Calmodulin Protein towards Conformational Shift by Changing Ionization States of Select Residues

    International Nuclear Information System (INIS)

    Negi, Sunita; Atilgan, Ali Rana; Atilgan, Canan

    2012-01-01

    Proteins are complex systems made up of many conformational sub-states which are mainly determined by the folded structure. External factors such as solvent type, temperature, pH and ionic strength play a very important role in the conformations sampled by proteins. Here we study the conformational multiplicity of calmodulin (CaM) which is a protein that plays an important role in calcium signaling pathways in the eukaryotic cells. CaM can bind to a variety of other proteins or small organic compounds, and mediates different physiological processes by activating various enzymes. Binding of calcium ions and proteins or small organic molecules to CaM induces large conformational changes that are distinct to each interacting partner. In particular, we discuss the effect of pH variation on the conformations of CaM. By using the pKa values of the charged residues as a basis to assign protonation states, the conformational changes induced in CaM by reducing the pH are studied by molecular dynamics simulations. Our current view suggests that at high pH, barrier crossing to the compact form is prevented by repulsive electrostatic interactions between the two lobes. At reduced pH, not only is barrier crossing facilitated by protonation of residues, but also conformations which are on average more compact are attained. The latter are in accordance with the fluorescence resonance energy transfer experiment results of other workers. The key events leading to the conformational change from the open to the compact conformation are (i) formation of a salt bridge between the N-lobe and the linker, stabilizing their relative motions, (ii) bending of the C-lobe towards the N-lobe, leading to a lowering of the interaction energy between the two-lobes, (iii) formation of a hydrophobic patch between the two lobes, further stabilizing the bent conformation by reducing the entropic cost of the compact form, (iv) sharing of a Ca +2 ion between the two lobes.

  2. Driving Calmodulin Protein towards Conformational Shift by Changing Ionization States of Select Residues

    Science.gov (United States)

    Negi, Sunita; Rana Atilgan, Ali; Atilgan, Canan

    2012-12-01

    Proteins are complex systems made up of many conformational sub-states which are mainly determined by the folded structure. External factors such as solvent type, temperature, pH and ionic strength play a very important role in the conformations sampled by proteins. Here we study the conformational multiplicity of calmodulin (CaM) which is a protein that plays an important role in calcium signaling pathways in the eukaryotic cells. CaM can bind to a variety of other proteins or small organic compounds, and mediates different physiological processes by activating various enzymes. Binding of calcium ions and proteins or small organic molecules to CaM induces large conformational changes that are distinct to each interacting partner. In particular, we discuss the effect of pH variation on the conformations of CaM. By using the pKa values of the charged residues as a basis to assign protonation states, the conformational changes induced in CaM by reducing the pH are studied by molecular dynamics simulations. Our current view suggests that at high pH, barrier crossing to the compact form is prevented by repulsive electrostatic interactions between the two lobes. At reduced pH, not only is barrier crossing facilitated by protonation of residues, but also conformations which are on average more compact are attained. The latter are in accordance with the fluorescence resonance energy transfer experiment results of other workers. The key events leading to the conformational change from the open to the compact conformation are (i) formation of a salt bridge between the N-lobe and the linker, stabilizing their relative motions, (ii) bending of the C-lobe towards the N-lobe, leading to a lowering of the interaction energy between the two-lobes, (iii) formation of a hydrophobic patch between the two lobes, further stabilizing the bent conformation by reducing the entropic cost of the compact form, (iv) sharing of a Ca+2 ion between the two lobes.

  3. Salvage conformal radiotherapy for biochemical recurrent prostate cancer after radical prostatectomy

    International Nuclear Information System (INIS)

    Monti, Carlos R.; Nakamura, Ricardo A.; Ferrigno, Robson; Rossi Junior, Aristides; Kawakami, Neusa S.; Trevisan, Felipe A.

    2006-01-01

    Objective: Assess the results of salvage conformal radiotherapy in patients with biochemical failure after radical prostatectomy and identify prognostic factors for biochemical recurrence and toxicity of the treatment. Materials and methods: From June 1998 to November 2001, 35 patients were submitted to conformal radiotherapy for PSA ≥ 0.2 ng/mL in progression after radical prostatectomy and were retrospectively analyzed. The mean dose of radiation in prostatic bed was of 77.4 Gy (68-81). Variables related to the treatment and to tumor were assessed to identify prognostic factors for biochemical recurrence after salvage radiotherapy. Results: The median follow-up was of 55 months (17-83). The actuarial survival rates free of biochemical recurrence and free of metastasis at a distance of 5 years were 79.7% e 84.7%, respectively. The actuarial global survival rate in 5 years was 96.1%.The actuarial survival rate free of biochemical recurrence in 5 years was 83.3% with PSA pre-radiotherapy ≤ 1, 100% when > 1 and ≤ 2, and 57.1% when > 2 (p = 0.023). Dose > 70 Gy in 30% of the bladder volume implied in more acute urinary toxicity (p = 0.035). The mean time for the development of late urinary toxicity was 21 months (12-51). Dose > 55 Gy in 50% bladder volume implied in more late urinary toxicity (p = 0.018). A patient presented late rectal toxicity of second grade. Conclusions: Conformal radiotherapy showed to be effective for the control of biochemical recurrence after radical prostatectomy. Patients with pre-therapy PSA < 2 ng/mL have more biochemical control. (author)

  4. Conformations of cationized linear oligosaccharides revealed by FTMS combined with in-ESI H/D exchange.

    Science.gov (United States)

    Kostyukevich, Yury; Kononikhin, Alexey; Popov, Igor; Nikolaev, Eugene

    2015-10-01

    Previously (Kostyukevich et al. Anal Chem 2014, 86, 2595), we have reported that oligosaccharides anions are produced in the electrospray in two different conformations, which differ by the rate of gas phase hydrogen/deuterium (H/D) exchange reaction. In the present paper, we apply the in-electrospray ionization (ESI) source H/D exchange approach for the investigation of the oligosaccharides cations formed by attaching of metal ions (Na, K) to the molecule. It was observed that the formation of different conformers can be manipulated by varying the temperature of the desolvating capillary of the ESI interphase. Separation of the conformers was performed using gas phase H/D approach. Because the conformers have different rates of the H/D exchange reaction, the deuterium distribution spectrum becomes bimodal. It was found that the conformation corresponding to the slow H/D exchange rate dominates in the spectrum when the capillary temperature is low (~200 °C), and the conformation corresponding to the fast H/D exchange rate dominates at high (~400 °C) temperatures. In the intermediate temperature region, two conformers are present simultaneously. It was also observed that large oligosaccharide requires higher temperature for the formation of another conformer. It was found that the presence of the conformers considerably depends on the solvent used for ESI and the pH. We have compared these results with the previously performed in-ESI source H/D exchange experiments with peptides and proteins. Copyright © 2015 John Wiley & Sons, Ltd.

  5. Promiscuity and the conformational rearrangement of drug-like molecules: insight from the protein data bank.

    Science.gov (United States)

    He, Michael W; Lee, Patrick S; Sweeney, Zachary K

    2015-02-01

    Selectivity is a central aspect of lead optimization in the drug discovery process. Medicinal chemists often try to decrease molecular flexibility to improve selectivity, given the common belief that the two are interdependent. To investigate the relationship between polypharmacology and conformational flexibility, we mined the Protein Data Bank and constructed a dataset of pharmaceutically relevant ligands that crystallized in more than one protein target while binding to each co-crystallized receptor with similar in vitro affinities. After analyzing the molecular conformations of these 100 ligands, we found that 59 ligands bound to different protein targets without significantly changing conformation, suggesting that there is no distinct correlation between conformational flexibility and polypharmacology within our dataset. Ligands crystallized in similar proteins and highly ligand-efficient compounds with five or fewer rotatable bonds were less likely to adjust conformation when binding. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Role of Detergents in Conformational Exchange of a G Protein-coupled Receptor*

    Science.gov (United States)

    Chung, Ka Young; Kim, Tae Hun; Manglik, Aashish; Alvares, Rohan; Kobilka, Brian K.; Prosser, R. Scott

    2012-01-01

    The G protein-coupled β2-adrenoreceptor (β2AR) signals through the heterotrimeric G proteins Gs and Gi and β-arrestin. As such, the energy landscape of β2AR-excited state conformers is expected to be complex. Upon tagging Cys-265 of β2AR with a trifluoromethyl probe, 19F NMR was used to assess conformations and possible equilibria between states. Here, we report key differences in β2AR conformational dynamics associated with the detergents used to stabilize the receptor. In dodecyl maltoside (DDM) micelles, the spectra are well represented by a single Lorentzian line that shifts progressively downfield with activation by appropriate ligand. The results are consistent with interconversion between two or more states on a time scale faster than the greatest difference in ligand-dependent chemical shift (i.e. >100 Hz). Given that high detergent off-rates of DDM monomers may facilitate conformational exchange between functional states of β2AR, we utilized the recently developed maltose-neopentyl glycol (MNG-3) diacyl detergent. In MNG-3 micelles, spectra indicated at least three distinct states, the relative populations of which depended on ligand, whereas no ligand-dependent shifts were observed, consistent with the slow exchange limit. Thus, detergent has a profound effect on the equilibrium kinetics between functional states. MNG-3, which has a critical micelle concentration in the nanomolar regime, exhibits an off-rate that is 4 orders of magnitude lower than that of DDM. High detergent off-rates are more likely to facilitate conformational exchange between distinct functional states associated with the G protein-coupled receptor. PMID:22893704

  7. Role of detergents in conformational exchange of a G protein-coupled receptor.

    Science.gov (United States)

    Chung, Ka Young; Kim, Tae Hun; Manglik, Aashish; Alvares, Rohan; Kobilka, Brian K; Prosser, R Scott

    2012-10-19

    The G protein-coupled β(2)-adrenoreceptor (β(2)AR) signals through the heterotrimeric G proteins G(s) and G(i) and β-arrestin. As such, the energy landscape of β(2)AR-excited state conformers is expected to be complex. Upon tagging Cys-265 of β(2)AR with a trifluoromethyl probe, (19)F NMR was used to assess conformations and possible equilibria between states. Here, we report key differences in β(2)AR conformational dynamics associated with the detergents used to stabilize the receptor. In dodecyl maltoside (DDM) micelles, the spectra are well represented by a single Lorentzian line that shifts progressively downfield with activation by appropriate ligand. The results are consistent with interconversion between two or more states on a time scale faster than the greatest difference in ligand-dependent chemical shift (i.e. >100 Hz). Given that high detergent off-rates of DDM monomers may facilitate conformational exchange between functional states of β(2)AR, we utilized the recently developed maltose-neopentyl glycol (MNG-3) diacyl detergent. In MNG-3 micelles, spectra indicated at least three distinct states, the relative populations of which depended on ligand, whereas no ligand-dependent shifts were observed, consistent with the slow exchange limit. Thus, detergent has a profound effect on the equilibrium kinetics between functional states. MNG-3, which has a critical micelle concentration in the nanomolar regime, exhibits an off-rate that is 4 orders of magnitude lower than that of DDM. High detergent off-rates are more likely to facilitate conformational exchange between distinct functional states associated with the G protein-coupled receptor.

  8. Conformal spinel/layered heterostructures of Co3O4 shells grown on single-crystal Li-rich nanoplates for high-performance lithium-ion batteries

    Science.gov (United States)

    Xin, Yue; Lan, Xiwei; Chang, Peng; Huang, Yaqun; Wang, Libin; Hu, Xianluo

    2018-07-01

    Lithium-rich layered materials have received much attention because of their high specific capacity and high energy density. Unfortunately, they suffer from irreversible capacity loss, low initial Coulombic efficiency and poor cyclability. Here we report a facile co-precipitation method to synthesize uniform single-crystal Li-rich Li[Li0.2Mn0.54Ni0.13Co0.13]O2 nanoplates without using any template. Subsequently, a Co3O4 shell is in situ grown on the Li-rich nanoplates through a hydrothermal method, leading to spinel/layered heterostructures. The electrode made of conformal heterostructured Li-rich/Co3O4 nanoplates delivers a high discharge capacity of 296 mA h g-1 at 0.1 C with an initial Coulombic efficiency of 84%. The capacity retention reaches 83.2% with a discharge capacity of 223 mA h g-1 after 160 cycles at 0.2 C during the potential window ranging from 2.0 to 4.8 V. The enhanced electrochemical performance of the resulting Li-rich/Co3O4 nanoplates benefits from the unique conformal heterostructure as well as the electrochemically active LixCoOy generated between the reaction of Co3O4 shells and the extracted Li2O during charging/discharging processes.

  9. Elementary introduction to conformal invariance

    International Nuclear Information System (INIS)

    Grandati, Y.

    1992-01-01

    These notes constitute an elementary introduction to the concept of conformal invariance and its applications to the study of bidimensional critical phenomena. The aim is to give an access as pedestrian as possible to this vast subject. After a brief account of the general properties of conformal transformation in D dimensions, we study more specifically the case D = 2. The center of the discussion is then the consequences of the action of this symmetry group on bidimensional field theories, and in particular the links between the representations of the Virasoro algebra and the structure of the correlation functions of conformal field theories. Finally after showing how the Ising model reduces to a Majorana fermionic field theory, we see how the general formalism previously discussed can be applied to the Ising case at the critical point. (orig.)

  10. Conformational changes in glycine tri- and hexapeptide

    DEFF Research Database (Denmark)

    Yakubovich, Alexander V.; Solov'yov, Ilia; Solov'yov, Andrey V.

    2006-01-01

    conformations and calculated the energy barriers for transitions between them. Using a thermodynamic approach, we have estimated the times of the characteristic transitions between these conformations. The results of our calculations have been compared with those obtained by other theoretical methods...... also investigated the influence of the secondary structure of polypeptide chains on the formation of the potential energy landscape. This analysis has been performed for the sheet and the helix conformations of chains of six amino acids....

  11. Conformal invariance in the quantum field theory

    International Nuclear Information System (INIS)

    Kurak, V.

    1975-09-01

    Basic features concerning the present knowledge of conformal symmetry are illustrated in a simple model. Composite field dimensions of this model are computed and related to the conformal group. (author) [pt

  12. Non-local Effects of Conformal Anomaly

    Science.gov (United States)

    Meissner, Krzysztof A.; Nicolai, Hermann

    2018-03-01

    It is shown that the nonlocal anomalous effective actions corresponding to the quantum breaking of the conformal symmetry can lead to observable modifications of Einstein's equations. The fact that Einstein's general relativity is in perfect agreement with all observations including cosmological or recently observed gravitational waves imposes strong restrictions on the field content of possible extensions of Einstein's theory: all viable theories should have vanishing conformal anomalies. It is shown that a complete cancellation of conformal anomalies in D=4 for both the C^2 invariant and the Euler (Gauss-Bonnet) invariant can only be achieved for N-extended supergravity multiplets with N ≥ 5.

  13. Mangiferin binding to serum albumin is non-saturable and induces conformational changes at high concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, P.G.; Barbosa, A.F. [Biochemistry Laboratory, Institute of Exact Sciences, Federal University of Alfenas, Unifal-MG, R. Gabriel Monteiro da Silva, 700, 37130-000 Alfenas, MG (Brazil); Saraiva, L.A. [Phytochemistry and Medicinal Chemistry Laboratory, Institute of Exact Sciences, Unifal-MG (Brazil); Camps, I. [Physics Laboratory, Institute of Exact Sciences, Unifal-MG (Brazil); Silveira, N.J.F. da [Bioinformatics Laboratory, Institute of Exact Sciences, Unifal-MG (Brazil); Veloso, M.P. [Phytochemistry and Medicinal Chemistry Laboratory, Institute of Exact Sciences, Unifal-MG (Brazil); Santos, M.H., E-mail: poliany.santos@gmail.com [Phytochemistry and Medicinal Chemistry Laboratory, Institute of Exact Sciences, Unifal-MG (Brazil); Schneedorf, J.M., E-mail: zemasfs@gmail.com [Biochemistry Laboratory, Institute of Exact Sciences, Federal University of Alfenas, Unifal-MG, R. Gabriel Monteiro da Silva, 700, 37130-000 Alfenas, MG (Brazil)

    2012-11-15

    The binding interaction between mangiferin (MGF), which a natural xanthone isolated from mangoes, and bovine serum albumin (BSA) was studied with absorbance and fluorescence spectroscopy, cyclic voltammetry and molecular modeling. The data were analyzed to assess the binding mechanism, effect of pH and ionic strength, conformational changes in the protein and electrical charge transfer involved. The MGF-BSA complex exhibited positive cooperativity with a 1:1 stoichiometry (K{sub d}=0.38 mmol L{sup -1}) for the first binding site and a non-saturable binding at high ligand concentrations. Furthermore, the data also suggest an increase in drug bioavailability in the acidic region and relatively low ionic strength values, which are close to physiological levels. The data suggest a specific electrostatic interaction together with hydrophobic effects and H-bonding displayed in MGF binding to the BSA IIA subdomain. Synchronous fluorescence spectra indicate that there are conformational changes in the polypeptide backbone upon ligand binding. Cyclic voltammetry indicates that there is an irreversible charge transfer between MGF and BSA that is modulated by diffusion on the electrode surface, where two electrons are transferred. These results can help the knowledge of the pharmacokinetic activities of natural or chemical xanthone-based drugs. - Highlights: Black-Right-Pointing-Pointer The MGF-BSA complex exhibited positive cooperativity beyond 1:1 stoichiometry. Black-Right-Pointing-Pointer The interaction of MGF with BSA is non-saturable at higher ligand concentration. Black-Right-Pointing-Pointer The binding was accomplished by H-bonding, hydrophobic and electrostatic forces. Black-Right-Pointing-Pointer The apparent binding constant for MGF-BSA was 0.38 mmol L{sup -1}. Black-Right-Pointing-Pointer MGF binds electrostatically to BSA, different from a hydrophobic interaction to HSA.

  14. Seed conformal blocks in 4D CFT

    Energy Technology Data Exchange (ETDEWEB)

    Echeverri, Alejandro Castedo; Elkhidir, Emtinan; Karateev, Denis [SISSA and INFN,Via Bonomea 265, I-34136 Trieste (Italy); Serone, Marco [SISSA and INFN,Via Bonomea 265, I-34136 Trieste (Italy); ICTP,Strada Costiera 11, I-34151 Trieste (Italy)

    2016-02-29

    We compute in closed analytical form the minimal set of “seed' conformal blocks associated to the exchange of generic mixed symmetry spinor/tensor operators in an arbitrary representation (ℓ,ℓ̄) of the Lorentz group in four dimensional conformal field theories. These blocks arise from 4-point functions involving two scalars, one (0,|ℓ−ℓ̄|) and one (|ℓ−ℓ̄|,0) spinors or tensors. We directly solve the set of Casimir equations, that can elegantly be written in a compact form for any (ℓ,ℓ̄), by using an educated ansatz and reducing the problem to an algebraic linear system. Various details on the form of the ansatz have been deduced by using the so called shadow formalism. The complexity of the conformal blocks depends on the value of p=|ℓ−ℓ̄| and grows with p, in analogy to what happens to scalar conformal blocks in d even space-time dimensions as d increases. These results open the way to bootstrap 4-point functions involving arbitrary spinor/tensor operators in four dimensional conformal field theories.

  15. Conformal invariance in the long-range Ising model

    Directory of Open Access Journals (Sweden)

    Miguel F. Paulos

    2016-01-01

    Full Text Available We consider the question of conformal invariance of the long-range Ising model at the critical point. The continuum description is given in terms of a nonlocal field theory, and the absence of a stress tensor invalidates all of the standard arguments for the enhancement of scale invariance to conformal invariance. We however show that several correlation functions, computed to second order in the epsilon expansion, are nontrivially consistent with conformal invariance. We proceed to give a proof of conformal invariance to all orders in the epsilon expansion, based on the description of the long-range Ising model as a defect theory in an auxiliary higher-dimensional space. A detailed review of conformal invariance in the d-dimensional short-range Ising model is also included and may be of independent interest.

  16. Conformal Invariance in the Long-Range Ising Model

    CERN Document Server

    Paulos, Miguel F; van Rees, Balt C; Zan, Bernardo

    2016-01-01

    We consider the question of conformal invariance of the long-range Ising model at the critical point. The continuum description is given in terms of a nonlocal field theory, and the absence of a stress tensor invalidates all of the standard arguments for the enhancement of scale invariance to conformal invariance. We however show that several correlation functions, computed to second order in the epsilon expansion, are nontrivially consistent with conformal invariance. We proceed to give a proof of conformal invariance to all orders in the epsilon expansion, based on the description of the long-range Ising model as a defect theory in an auxiliary higher-dimensional space. A detailed review of conformal invariance in the d-dimensional short-range Ising model is also included and may be of independent interest.

  17. Conformal invariance in the long-range Ising model

    Energy Technology Data Exchange (ETDEWEB)

    Paulos, Miguel F. [CERN, Theory Group, Geneva (Switzerland); Rychkov, Slava, E-mail: slava.rychkov@lpt.ens.fr [CERN, Theory Group, Geneva (Switzerland); Laboratoire de Physique Théorique de l' École Normale Supérieure (LPTENS), Paris (France); Faculté de Physique, Université Pierre et Marie Curie (UPMC), Paris (France); Rees, Balt C. van [CERN, Theory Group, Geneva (Switzerland); Zan, Bernardo [Institute of Physics, Universiteit van Amsterdam, Amsterdam (Netherlands)

    2016-01-15

    We consider the question of conformal invariance of the long-range Ising model at the critical point. The continuum description is given in terms of a nonlocal field theory, and the absence of a stress tensor invalidates all of the standard arguments for the enhancement of scale invariance to conformal invariance. We however show that several correlation functions, computed to second order in the epsilon expansion, are nontrivially consistent with conformal invariance. We proceed to give a proof of conformal invariance to all orders in the epsilon expansion, based on the description of the long-range Ising model as a defect theory in an auxiliary higher-dimensional space. A detailed review of conformal invariance in the d-dimensional short-range Ising model is also included and may be of independent interest.

  18. Conformational stability and self-association equilibrium in biologics.

    Science.gov (United States)

    Clarkson, Benjamin R; Schön, Arne; Freire, Ernesto

    2016-02-01

    Biologics exist in equilibrium between native, partially denatured, and denatured conformational states. The population of any of these states is dictated by their Gibbs energy and can be altered by changes in physical and solution conditions. Some conformations have a tendency to self-associate and aggregate, an undesirable phenomenon in protein therapeutics. Conformational equilibrium and self-association are linked thermodynamic functions. Given that any associative reaction is concentration dependent, conformational stability studies performed at different protein concentrations can provide early clues to future aggregation problems. This analysis can be applied to the selection of protein variants or the identification of better formulation solutions. In this review, we discuss three different aggregation situations and their manifestation in the observed conformational equilibrium of a protein. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Conformal Cosmology and Supernova Data

    OpenAIRE

    Behnke, Danilo; Blaschke, David; Pervushin, Victor; Proskurin, Denis

    2000-01-01

    We define the cosmological parameters $H_{c,0}$, $\\Omega_{m,c}$ and $\\Omega_{\\Lambda, c}$ within the Conformal Cosmology as obtained by the homogeneous approximation to the conformal-invariant generalization of Einstein's General Relativity theory. We present the definitions of the age of the universe and of the luminosity distance in the context of this approach. A possible explanation of the recent data from distant supernovae Ia without a cosmological constant is presented.

  20. Brainstem tolerance to conformal radiotherapy of skull base tumors

    International Nuclear Information System (INIS)

    Debus, J.; Hug, E.B.; Liebsch, N.J.; O'Farrel, D.; Finkelstein, D.; Efird, J.; Munzenrider, J.E.

    1997-01-01

    Purpose: The aim of this study was to analyze the long-term incidence of brainstem toxicity in patients treated for skull base tumors with high dose conformal radiotherapy. Methods and Materials: Between 1974 and 1995, 367 patients with chordomas (n = 195) and chondrosarcomas (n = 172) of the base of skull have been treated with combined megavoltage photon and 160 MeV proton radiotherapy. Following 3D treatment planning with delineation of target volumes and critical nontarget structures dose distributions and dose-volume histograms were calculated. Radiotherapy was given an 1.8 Gy or CGE (=Cobalt Gray Equivalent) dose per fraction, with prescribed target doses ranging from 63 CGE to 79.2 CGE (mean = 67.8 CGE). Doses to the brainstem surface were limited to ≤64 CGE and to the brainstem center to ≤53 CGE. Results: Follow-up time ranged from 6 months to 21.4 years (mean = 42.5 months). Brainstem toxicity was observed in 17 of 367 patients attributable to treatment, resulting in death of three patients. Actuarial rates of 5 and 10-year high-grade toxicity-free survival were 94 and 88%, respectively. Increased risk of brainstem toxicity was significantly associated with maximum dose to brainstem, volume of brainstem receiving ≥50 CGE, ≥55 CGE, and ≥60 CGE, number of surgical procedures, and prevalence of diabetes or high blood pressure. Multivariate analysis identified three independent factors as important prognosticators: number of surgical procedures (p < 0.001), volume of the brainstem receiving 60 CGE (p < 0.001), and prevalence of diabetes (p < 0.01). Conclusions: Tolerance of brainstem to fractionated radiotherapy appears to be a steep function of tissue volume included in high dose regions rather than the maximum dose of brainstem alone. In addition, presence of predisposing factors as well as extent of surgical manipulation can significantly lower brainstem tolerance in the individual patient