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Sample records for histiocytosis fascinating dynamics

  1. Fascismens fascination

    DEFF Research Database (Denmark)

    Skov, Christian Egander

    2014-01-01

    Kapitel skildrer fascismens fascination primært hos en række konservative og højreradikale intellektuelle i Danmark i 1920'erne og 1930'erne......Kapitel skildrer fascismens fascination primært hos en række konservative og højreradikale intellektuelle i Danmark i 1920'erne og 1930'erne...

  2. Malignant histiocytosis. Case report

    OpenAIRE

    Ruiz, Oscar; Instituto de Investigaciones Clínicas, Facultad de Medicina, UNMSM, y Hospital Nacional Dos de Mayo; QUIÑONES, WILLY; Servicio Hematologia Clínica, Hospital Dos de Mayo; MISAD, OSCAR; Laboratorio de Anatomia Patológica “Oscar Misad; DELGADO, CARLOS; Instituto de Investigaciones Clínicas, UNMSM; Servicio Hematologia Clínica, Hospital Dos de Mayo; Ronceros, Sergio; Instituto de Investigaciones Clínicas, Facultad de Medicina, Universidad Nacional Mayor de San Marcos, Lima, Perú.; Marangoni, Manuela; Departamento de Enfermería, Hospital Nacional Dos de Mayo. Lima, Perú; BARDALES, LUZ; Servicio Hematologia Clínica, Hospital Dos de Mayo; REYES, RAFAEL; Servicio Hematologia Clínica, Hospital Dos de Mayo; CASTILLO, ALFREDO; Servicio Hematologia Clínica, Hospital Dos de Mayo; URRUTIA, KATIA; Servicio Hematologia Clínica, Hospital Dos de Mayo

    2013-01-01

    Fourteen year-old male patient referred from Huancayo who presented one month gastric intolerance, jaundice, fever and a lymph proliferative syndrome. Laboratory tests revealed severe pancytopenia due to phagocytosis. Haematologic and anatomy-pathology diagnosis was human malignant histiocytosis. We present this case due to its low frequency and the emergency character of the disease. Paciente varón de 14 años, procedente de Huancayo, que presenta un mes antes de su hospitalización intoler...

  3. Fascinating Organic Transformations

    Indian Academy of Sciences (India)

    RESONANCE │ December 2011. Fascinating Organic Transformations. 2. The Ubiquitous Hydrogen Bond. Subramania Ranganathan. Hydrogen bonds can transform simple molecules into beauti- ful architectures. This is well illustrated in this article. Organic transformations are generally assumed to involve reactions.

  4. Fascinating Organic Transformations

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 16; Issue 12. Fascinating Organic Transformations - The Ubiquitous Hydrogen Bond. Subramania Ranganathan. Volume 16 Issue 12 December 2011 pp 1307-1314. Fulltext. Click here to view fulltext PDF. Permanent link:

  5. Pulmonary langerhans cell histiocytosis

    Directory of Open Access Journals (Sweden)

    Suri Harpreet S

    2012-03-01

    Full Text Available Abstract Pulmonary Langerhans Cell Histiocytosis (PLCH is a relatively uncommon lung disease that generally, but not invariably, occurs in cigarette smokers. The pathologic hallmark of PLCH is the accumulation of Langerhans and other inflammatory cells in small airways, resulting in the formation of nodular inflammatory lesions. While the overwhelming majority of patients are smokers, mechanisms by which smoking induces this disease are not known, but likely involve a combination of events resulting in enhanced recruitment and activation of Langerhans cells in small airways. Bronchiolar inflammation may be accompanied by variable lung interstitial and vascular involvement. While cellular inflammation is prominent in early disease, more advanced stages are characterized by cystic lung destruction, cicatricial scarring of airways, and pulmonary vascular remodeling. Pulmonary function is frequently abnormal at presentation. Imaging of the chest with high resolution chest CT scanning may show characteristic nodular and cystic abnormalities. Lung biopsy is necessary for a definitive diagnosis, although may not be required in instances were imaging findings are highly characteristic. There is no general consensus regarding the role of immunosuppressive therapy in smokers with PLCH. All smokers must be counseled on the importance of smoking cessation, which may result in regression of disease and obviate the need for systemic immunosuppressive therapy. The prognosis for most patients is relatively good, particularly if longitudinal lung function testing shows stability. Complications like pneumothoraces and secondary pulmonary hypertension may shorten life expectancy. Patients with progressive disease may require lung transplantation.

  6. Steroids: A Timeless Fascination

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 2. Steroids: A Timeless Fascination - Cholesterol and its Bio-products. S Hari Prasad. General Article Volume 9 Issue 2 February 2004 pp 80-84. Fulltext. Click here to view fulltext PDF. Permanent link:

  7. Fascinating Organic Transformations

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 4. Fascinating Organic Transformations The Ubiquitous Hydrogen Bond. Subramania Ranganathan. Series Article Volume 1 Issue 4 April 1996 pp 23-30. Fulltext. Click here to view fulltext PDF. Permanent link:

  8. Histiocytosis mimicking a pineal gland tumour

    Energy Technology Data Exchange (ETDEWEB)

    Gizewski, E.R.; Forsting, M. [Dept. of Neuroradiology, Univ. of Essen (Germany)

    2001-08-01

    We report an unusual case of isolated Langerhans cell histiocytosis of the central nervous system. A 19-year-old man presented with an incomplete ocular palsy. MRI revealed a solitary mass in the pineal gland with marked contrast enhancement. Complete microsurgical excision was followed by local radiotherapy. Histological examination revealed histiocytosis. Unifocal brain involvement by histiocytosis X is rare with few cases in the literature; the most commonly involved areas are the hypothalamus and the pituitary gland. (orig.)

  9. Langerhans cell histiocytosis (histiocytosis x) – in the mandible

    OpenAIRE

    Camargo, Angela Jordão; São Paulo University; Cheade, Mayara; Departament of Oral Radiology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil; Martinelli, Celso; Departament of Morphology, Stomatology and Physiology, Ribeirão Preto School of Dentistry, University of São Paulo, Ribeirão Preto, SP, Brazil; Monteiro, Solange Aparecida Caldeira; São Paulo University; Santos, Christiano de Oliveira; São Paulo University; Watanabe, Plauto Christopher Aranha; São Paulo University

    2013-01-01

    This article reports a case of 65 year-old man consultedin a private radiology dental clinic for a panoramicradiography, where was indicated a radiolucent area,extending into the periapical region of the teeth 35 to 43 to the base of the mandible. Radiographydiagnosis was difficult. The immunohistochemical examination showed immunoreactivity for theproteins CD 68, S-100 and CD 1a. Histopathologicaldiagnosis was obtained for Langerhans cell granuloma(histiocytosis X). Langerhans cell histiocyt...

  10. Radiologic features in histiocytosis syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sung Mo; Cho, Byung Jae; Yeon, Kyung Mo [College of Medicine, Seoul National University, Seoul (Korea, Republic of)

    1980-12-15

    Histiocytosis syndrome is not rare disease of unknown etiology, characterized by development of granulomatous lesions with histiocytic proliferation. Authors analyzed 22 cases, which had been confirmed as histiocytosis syndrome from 1971 to Feb. 1980 with special attention to 15 cases showing positive findings on radiological examinations. The results are as follows. 1. Overall male to female ratio was about 2:1. The majority were between 1 and 7 years of age. 2. Skeletal system was involved in orders as follows: skull, pelvis, femur, rib, spine. 3. Four cases of pulmonary involvement were experienced. All cases had interstitial involvement with reticulonodular densities on roentgenograms. 4. We had experienced a pituitary tumor, presumably localized histiocytic mass, in a patient with diabetes insipidus. 5. In long bone involvement, diaphysis or metaphysis was usually involved, but in one patient, lesion were extended into epiphysis. 6. One case of platyspondyly was found, with symmetrical compression.

  11. Monoubiquitination Inhibits the Actin Bundling Activity of Fascin.

    Science.gov (United States)

    Lin, Shengchen; Lu, Shuang; Mulaj, Mentor; Fang, Bin; Keeley, Tyler; Wan, Lixin; Hao, Jihui; Muschol, Martin; Sun, Jianwei; Yang, Shengyu

    2016-12-30

    Fascin is an actin bundling protein that cross-links individual actin filaments into straight, compact, and stiff bundles, which are crucial for the formation of filopodia, stereocillia, and other finger-like membrane protrusions. The dysregulation of fascin has been implicated in cancer metastasis, hearing loss, and blindness. Here we identified monoubiquitination as a novel mechanism that regulates fascin bundling activity and dynamics. The monoubiquitination sites were identified to be Lys247 and Lys250, two residues located in a positive charge patch at the actin binding site 2 of fascin. Using a chemical ubiquitination method, we synthesized chemically monoubiquitinated fascin and determined the effects of monoubiquitination on fascin bundling activity and dynamics. Our data demonstrated that monoubiquitination decreased the fascin bundling EC50, delayed the initiation of bundle assembly, and accelerated the disassembly of existing bundles. By analyzing the electrostatic properties on the solvent-accessible surface of fascin, we proposed that monoubiquitination introduced steric hindrance to interfere with the interaction between actin filaments and the positively charged patch at actin binding site 2. We also identified Smurf1 as a E3 ligase regulating the monoubiquitination of fascin. Our findings revealed a previously unidentified regulatory mechanism for fascin, which will have important implications for the understanding of actin bundle regulation under physiological and pathological conditions. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. Strong fascin expression promotes metastasis independent of its F-actin bundling activity.

    Science.gov (United States)

    Heinz, Lisa S; Muhs, Stefanie; Schiewek, Johanna; Grüb, Saskia; Nalaskowski, Marcus; Lin, Yuan-Na; Wikman, Harriet; Oliveira-Ferrer, Leticia; Lange, Tobias; Wellbrock, Jasmin; Konietzny, Anja; Mikhaylova, Marina; Windhorst, Sabine

    2017-12-15

    High expression of the actin bundling protein Fascin increases the malignancy of tumor cells. Here we show that fascin expression is up-regulated in more malignant sub-cell lines of MDA-MB-231 cells as compared to parental cells. Since also parental MDA-MB-231 cells exhibit high fascin levels, increased fascin expression was termed as "hyperexpression". To examine the effect of fascin hyperexpression, fascin was hyperexpressed in parental MDA-MB-231 cells and metastasis was analyzed in NOD scid gamma (NSG) mice. In addition, the effect of fascin mutants with inactive or constitutively active actin bundling activity was examined. Unexpectedly, we found that hyperexpression of both, wildtype (wt) and mutant fascin strongly increased metastasis in vivo , showing that the effect of fascin hyperexpression did not depend on its actin bundling activity. Cellular assays revealed that hyperexpression of wt and mutant fascin increased adhesion of MDA-MB-231 cells while transmigration and proliferation were not affected. Since it has been shown that fascin controls adhesion by directly interacting with microtubules ( MTs), we analyzed if fascin hyperexpression affects MT dynamics. We found that at high concentrations fascin significantly increased MT dynamics in cells and in cell-free approaches. In summary our data show that strong expression of fascin in breast cancer cells increases metastasis independent of its actin bundling activity. Thus, it seems that the mechanism of fascin-stimulated metastasis depends on its concentration.

  13. Histiocytosis

    Science.gov (United States)

    ... if the BRAF V600E mutation is found Stem cell transplantation Other treatments may include: Antibiotics to fight infections Breathing support (with a breathing machine) Hormone replacement therapy ...

  14. p53 Is a Helpful Marker in Distinguishing Langerhans Cell Histiocytosis From Langerhans Cell Hyperplasia.

    Science.gov (United States)

    Grace, Shane A; Sutton, Angela M; Armbrecht, Eric S; Vidal, Claudia I; Rosman, Ilana S; Hurley, Maria Y

    2017-10-01

    Langerhans cell histiocytosis (LCH) is a proliferative disorder of Langerhans cells that can be challenging to distinguish histologically from Langerhans cell (LC) hyperplasia, seen in a variety of inflammatory dermatoses. Lesional cells in both entities demonstrate positive staining for CD1a and S100. Previous studies have demonstrated positive staining of fascin, CD31, and p53 in cases of LCH, but currently, no studies have compared the staining profiles of these markers between LCH and LC hyperplasia. The authors compared immunohistochemical staining profiles of LCH (n = 15) and various inflammatory dermatoses with LC hyperplasia (n = 15) using fascin, CD31, and p53. Fascin, CD31, and p53 were graded as a percentage of CD1a staining cells in the epidermis and dermis of each specimen. Fascin showed no significant differences in staining between the 2 entities. CD31 was positive in the dermal infiltrate in 40% of cases of LCH and negative in all cases of LC hyperplasia. p53 was positive in the epidermal infiltrate in 50% of cases of LCH, and positive in the dermal infiltrate in 93% of cases of LCH, whereas negative in all cases of LC hyperplasia. Fascin was not a helpful marker in distinguishing LCH from LC hyperplasia. CD31, if positive in the dermal infiltrate, is suggestive of a diagnosis of LCH, but exhibits a relatively low sensitivity for this purpose. p53 proved to be a helpful and accurate diagnostic immunohistochemical stain when distinguishing between LCH and LC hyperplasia.

  15. [Langerhans cell histiocytosis in adults].

    Science.gov (United States)

    Néel, A; Artifoni, M; Donadieu, J; Lorillon, G; Hamidou, M; Tazi, A

    2015-10-01

    Langerhans cell histiocytosis (LCH) is a rare disease characterized by the infiltration of one or more organs by Langerhans cell-like dendritic cells, most often organized in granulomas. The disease has been initially described in children. The clinical picture of LCH is highly variable. Bone, skin, pituitary gland, lung, central nervous system, lymphoid organs are the main organs involved whereas liver and intestinal tract localizations are less frequently encountered. LCH course ranges from a fulminant multisystem disease to spontaneous resolution. Several randomized controlled trials have enable pediatricians to refine the management of children with LCH. Adult LCH has some specific features and poses distinct therapeutic challenges, knowing that data on these patients are limited. Herein, we will provide an overview of current knowledge regarding adult LCH and its management. We will also discuss recent advances in the understanding of the disease, (i.e. the role of BRAF oncogene) that opens the way toward targeted therapies. Copyright © 2015 Société nationale française de médecine interne (SNFMI). Published by Elsevier SAS. All rights reserved.

  16. Fascinating Organic Molecules from Nature

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 3. Fascinating Organic Molecules from Nature - Hunting with Poisoned Arrows: Story of Curare. N R Krishnaswamy C N Sundaresan. Series Article Volume 18 Issue 3 March 2013 pp 218-225 ...

  17. Fascinating Organic Molecules from Nature

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 1. Fascinating Organic Molecules from Nature - Colours in Flight - Pigments from Bird Feathers and Butterfly Wings. N R Krishnaswamy C N Sundaresan. Series Article Volume 18 Issue 1 January 2013 pp 12-21 ...

  18. Fascinating Organic Molecules from Nature

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 17; Issue 10. Fascinating Organic Molecules from Nature - Some Exotic Red Pigments of Plant Origin. N R Krishnaswamy C N Sundaresan. Series Article Volume 17 Issue 10 October 2012 pp 928-942 ...

  19. Fascinating Organic Molecules from Nature

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 7. Fascinating Organic Molecules from Nature - Sweet Stimulants of the Olfactory Nerves - Muscone, Civetone and Related Compounds. N R Krishnaswamy C N Sundaresan. Series Article Volume 18 Issue 7 July 2013 pp 673-683 ...

  20. Indeterminate cell histiocytosis: report of a case.

    Directory of Open Access Journals (Sweden)

    Alireza Ghanadan

    2014-10-01

    Full Text Available Indeterminate cell histiocytosis is a very rare disorder of histiocytes proliferation. It has both Langerhans and non-Langerhans cell histiocytosis immunophenotypic features. We described a 45-year-old man with a 2 years history of multiple yellow-brown papules and a few red nodules on his trunk and extremities. No internal involvement was detected first and after 8 months. As his lesions were asymptomatic and sparse, he didn't receive any treatment. He will be followed at regular intervals.

  1. Langerhans Cell Histiocytosis Involving Maxilla and Mandible

    Directory of Open Access Journals (Sweden)

    M. Guna Shekhar

    2009-06-01

    Full Text Available Langerhans cell histiocytosis is a relatively rare unique disease process characterized by an abnormal proliferation of immature dendritic cells usually affecting children and young adults. Jaws are involved in less than 10% of children with the disease while mandibular involvement in young children is uncommon and bilateral affection is very rare. The purpose of this report is to describe a unique and very rare case of simultaneous and bilateral occurrence of Langerhans cell histiocytosis in both the jaws of a four-year-old boy.

  2. Two rare cases of laryngeal intralymphatic histiocytosis

    DEFF Research Database (Denmark)

    Reznitsky, Martin; Daugaard, Søren; Charabi, Birgitte Wittenborg

    2016-01-01

    laryngoscopy was performed under general anesthesia due to minimal effect from treatment with antibiotics and anti-oedema medication. On examination, the larynx was found to be swollen and oedematous but not inflamed. Biopsies from the aryepiglottic folds showed intralymphatic histiocytosis. The patient...

  3. Paediatric neuroradiological aspects of Langerhans cell histiocytosis

    Energy Technology Data Exchange (ETDEWEB)

    Demaerel, Philippe [University Hospital K.U.Leuven, Department of Radiology, Leuven (Belgium); Gool, Stefaan van [University Hospital K.U.Leuven, Paediatric Haemato-oncology/Neuro-oncology, Leuven (Belgium)

    2008-01-15

    Langerhans cell histiocytosis, previously known as histiocytosis X, is a complex disease consisting of three entities that are all characterized by a proliferation of the Langerhans cell. The clinical course is variable and ranges from a solitary lytic bone or skin lesion with complete remission to a multisystem disorder with possible lethal outcome. The clinical suspicion can be increased based on radiological findings that are important criteria in defining the extent of the disease involvement. A biopsy is often necessary for establishing the final diagnosis. The lytic craniofacial bone lesions are the most common craniospinal abnormality in Langerhans cell histiocytosis. Abnormalities in the hypothalamic-pituitary region are the most frequent manifestations, often accompanied with diabetes insipidus as the presenting symptom. A range of different central nervous system abnormalities can be recognized. It is important to be able to recognize the extensive spectrum of neuroradiological abnormalities in order to arrive at the diagnosis. Neuroimaging plays an even more important role in assessing the response to treatment or possible relapse. (orig.)

  4. Making Physics Fascinating and Fun

    Science.gov (United States)

    Ramdass, Vede; White, Amanda; Harris, Wendy; Mlack, Jerome; Ramos, Roberto

    2010-02-01

    Since it's inception the Society of Physics Students at Drexel University established a goal of promoting and encouraging the pursuit of Physics or science among middle school students. As a result, we have established an outreach project that partners with a local Philadelphia middle school in order for us to expose the students to Physics concepts and theories that surpasses their curriculum in a way that is exciting. The program with the school involves bi-weekly meetings with students interested in science from both 7th and 8th grade classes. At each meeting we first talk about a general topic in physics, such as thermodynamics or kinetics, and then perform demonstrations that are designed to encourage their participation and hence enthusiasm towards the material. The program lasts for school year and culminates in a final project which tries to incorporate all the things they have learned. The final project and by extension the entire outreach has proven great success in motivating these students to becoming more involved in science and most importantly, proving to them that science is fascinating and fun. )

  5. Fascin regulates nuclear actin during Drosophila oogenesis.

    Science.gov (United States)

    Kelpsch, Daniel J; Groen, Christopher M; Fagan, Tiffany N; Sudhir, Sweta; Tootle, Tina L

    2016-10-01

    Drosophila oogenesis provides a developmental system with which to study nuclear actin. During Stages 5-9, nuclear actin levels are high in the oocyte and exhibit variation within the nurse cells. Cofilin and Profilin, which regulate the nuclear import and export of actin, also localize to the nuclei. Expression of GFP-tagged Actin results in nuclear actin rod formation. These findings indicate that nuclear actin must be tightly regulated during oogenesis. One factor mediating this regulation is Fascin. Overexpression of Fascin enhances nuclear GFP-Actin rod formation, and Fascin colocalizes with the rods. Loss of Fascin reduces, whereas overexpression of Fascin increases, the frequency of nurse cells with high levels of nuclear actin, but neither alters the overall nuclear level of actin within the ovary. These data suggest that Fascin regulates the ability of specific cells to accumulate nuclear actin. Evidence indicates that Fascin positively regulates nuclear actin through Cofilin. Loss of Fascin results in decreased nuclear Cofilin. In addition, Fascin and Cofilin genetically interact, as double heterozygotes exhibit a reduction in the number of nurse cells with high nuclear actin levels. These findings are likely applicable beyond Drosophila follicle development, as the localization and functions of Fascin and the mechanisms regulating nuclear actin are widely conserved. © 2016 Kelpsch et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  6. How I manage pulmonary Langerhans cell histiocytosis

    Directory of Open Access Journals (Sweden)

    Gwenaël Lorillon

    2017-09-01

    Full Text Available Pulmonary Langerhans cell histiocytosis (PLCH is a rare sporadic cystic lung disease of unknown aetiology that is characterised by the infiltration and destruction of the wall of distal bronchioles by CD1a+ Langerhans-like cells. In adults, PLCH is frequently isolated and affects young smokers of both sexes. Recent multicentre studies have led to the more standardised management of patients in clinical practice. Smoking cessation is essential and is occasionally the only suitable intervention. Serial lung function testing is important because a significant proportion of patients may experience an early decline in forced expiratory volume in 1 s and develop airflow obstruction. Cladribine was reported to dramatically improve progressive PLCH in some patients. Its efficacy and tolerance are currently being evaluated. Patients who complain of unexplained dyspnoea with decreased diffusing capacity of the lung for carbon monoxide should be screened for pulmonary hypertension by Doppler echocardiography, which must be confirmed by right heart catheterisation. Lung transplantation is a therapeutic option for patients with advanced PLCH. The identification of the BRAFV600E mutation in approximately half of Langerhans cell histiocytosis lesions, including PLCH, and other mutations of the mitogen-activated protein kinase (MAPK pathway in a subset of lesions has led to targeted treatments (BRAF and MEK (MAPK kinase inhibitors. These treatments need to be rigorously evaluated because of their potentially severe side-effects.

  7. Thoracolumbar Langerhans cell histiocytosis in a toddler

    Directory of Open Access Journals (Sweden)

    Zhi Gang Lan

    2018-01-01

    Full Text Available Introduction: Langerhans cell histiocytosis (LCH is a rare uni or multisystem disorder associated with extreme production of immunoreactive Langerhans cells. Although this disorder has been reported in all age groups, spinal involvement especially thoracolumbar spine is seldom reported in toddlers. Case presentation: We present a one (1 year, four (4 months female child with a history of recurrent fever, irritability and severe anemia of one (1 month duration. CT-scan and MRI revealed a collapsed twelfth thoracic vertebra (T12 body height greater than 95% with a huge intradural soft tissue mass. T12 cortectomy via posterior thoracolumbar approach was used to decompress the soft tissue part followed by interbody fusion with titanium cage filled with autologous iliac crest bone graft, fixation using plates and screws. Conclusion: We are of the view that surgical decompression of spinal LHC lesions with interbody fusion with titanium cage filled with autologous iliac crest bone graft and fixation using plates and screws is very crucial in relieving neurological deficits. However, the patient will need repeated surgeries as she advances with age in a timely manner to avert any neurological deficit that may occur. Keywords: Langerhans cell histiocytosis (LCH, Letterer-Siwe disease, Hand-Schüller-Christian disease, Eosinophilic granuloma

  8. Langerhans Cell Histiocytosis in Bilateral Mastoid Cavity

    Directory of Open Access Journals (Sweden)

    Kazım Bozdemir

    2013-01-01

    Full Text Available A 39-year-old male was admitted to our clinic with symptoms of headache, dizziness, nausea, otalgia, otorrhea, tinnitus, and hearing loss in both ears for 3 weeks. Physical examination revealed edema in the tympanic membrane and external ear canal, and pain by palpation in the mastoid area bilaterally. There was no nystagmus, and the rest of the physical examination was otherwise normal. Temporal bone high resolution computed tomography (CT showed a lesion causing erosion in the mastoid cortex, tegmen tympani, ossicles, and in the bone covering the sigmoid sinus bilaterally. There was also erosion in the superior semicircular canal and petrous bone on the left side. Cortical mastoidectomy was performed under general anesthesia. Histopathologic examination of the tissue revealed Langerhans cell histiocytosis (LCH. In this paper a case with LCH, presenting with bilateral mastoid involvement which has been rarely reported in the literature, is discussed with the existing literature.

  9. Intralymphatic Histiocytosis: A Report of 2 Cases.

    Science.gov (United States)

    Gómez-Sánchez, M E; Azaña-Defez, J M; Martínez-Martínez, M L; López-Villaescusa, M T

    Intralymphatic histiocytosis is a benign condition characterized by poorly defined erythematous plaques (sometimes forming a reticular pattern) as well as the presence of nodules and vesicles. Its etiology and pathogenesis appear to be related to chronic inflammation in the affected area, prior surgery, or systemic disease, particularly rheumatoid arthritis. We report on 2 new cases, both associated with joint surgery in the affected area and osteoarticular disease (primary synovial osteochondromatosis and rheumatoid arthritis). This is a chronic disease and there is no specific treatment. Different treatment options were chosen in the 2 cases described. A spectacular response to treatment with oral pentoxifylline and topical tacrolimus was observed in 1 of the patients. Copyright © 2017 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

  10. Histiocytosis X and Bronchopulmonary Adenocarcinoma: A Rare Coexistence

    Directory of Open Access Journals (Sweden)

    Akýn Kaya

    2002-01-01

    Full Text Available There exists a rarely observed association between pulmonary histiocytosis X and bronchopulmonary cancer. However, the frequency of bronchopulmonary cancer in these patients is higher than in the general population. A 28-year-old patient who currently smokes ten packs of cigarettes a year came to our department of pneumology with complains of cough and hemoptysis. An x-ray of the thorax revealed bilateral cysts and a shadow in the upper part of the right pulmonary field. In addition, a chest tomography showed multiple cysts dispersed throughout the two pulmonary fields and an irregular mass with a diameter of four centimetres in the upper right lobe. Bronchopulmonary adenocarcinoma was diagnosed during a cytologic exam of the bronchial washing. We decided to perform a thoracotomy on the patient, since there was no far metastasis. An upper lobectomy and wedge resection of the upper segment of the lower right lobe, which had been invaded by the tumour, were performed. Histology confirmed the diagnosis of adenocarcinoma. A pulmonary biopsy was carried out on the tumour-free site and showed the presence of histiocytosis X. There is a hypothesis that a neoplasm developed on the pulmonary fibrosis could be an epiphenomenon of bronchopulmonary cancer in patients who smoke and have pulmonary histiocytosis X. It is interesting to note that histiocytosis X and bronchopulmonary cancer were diagnosed at the same time, since the bronchopulmonary cancer may have occurred within a few years following the diagnosis of histiocytosis X, even if she was a smoker. Hemoptysis, which is found in 5% of patients with histiocytosis X, may suggest cancer. This young patient, a smoker, who complained of hemoptysis, is a particularly rare case of the association between pulmonary histiocytosis X and bronchopulmonary cancer whose pathogenesis is not clear cut. It is thus important to note that smoking can have major consequences, even in young people.

  11. Fascinating mathematical people interviews and memoirs

    CERN Document Server

    Alexanderson, Gerald L.

    2011-01-01

    Fascinating Mathematical People is a collection of informal interviews and memoirs of sixteen prominent members of the mathematical community of the twentieth century, many still active. The candid portraits collected here demonstrate that while these men and women vary widely in terms of their backgrounds, life stories, and worldviews, they all share a deep and abiding sense of wonder about mathematics.

  12. Langerhans Cell Histiocytosis Presenting as Uncontrolled Asthma

    Directory of Open Access Journals (Sweden)

    Frederic A. Rawlins

    2013-01-01

    Full Text Available Langerhans cell histiocytosis (LCH is an uncommon disorder affecting primarily young adult smokers. It is characterized by abnormal proliferation of Langerhans cells, specialized monocyte-macrophage lineage antigen-presenting cells. LCH can affect the lungs in isolation or as part of a systemic disease. Most commonly, the disease presents in the third or fourth decade without gender predominance. Symptoms typically include dyspnea and cough. Commonly, physical examination is unremarkable but cor pulmonale may be observed in advanced disease. The chest radiograph is typically abnormal with nodular or interstitial infiltrates and cystic changes. High-resolution computed tomography of the chest with these findings in the middle and upper lobes of an adult smoker is virtually diagnostic of LCH. Pulmonary function assessment is variable. Asthma has rarely been reported in association with this disorder. There are only three reported cases of the diagnosis of concomitant asthma which have been made in association with the diagnosis of LCH. We present a case in which our patient presented with signs and symptoms of asthma to include confirmatory findings of airway hyperresponsiveness. The diagnosis of LCH was established after the patient failed to respond to conventional treatment for asthma, and further evaluation was completed.

  13. Disseminated Langerhan's cell histiocytosis: A case report and ...

    African Journals Online (AJOL)

    Ramakantb

    Langerhan's cell histiocytosis (LCH) is characterized by the presence of large mononucleated cells, but occasional ones contain several nuclei, associated with inflammatory cells. Their nuclei are highly characteristic, irregular, usually elongated with prominent grooves and folds that traverse in all directions. The cytoplasm ...

  14. Sinus Histiocytosis with Massive Lymphadenopathy | Sinclair-Smith ...

    African Journals Online (AJOL)

    Two cases of a recently described entity, 'sinus histiocytosis with massive lymphadenopathy,' occurring in Black males, are reported. Prominent cervical adenopathy was the main presenting feature in both. Histologically, these nodes were characterised by pronounced proliferation of sinus histiocytes which showed ...

  15. MultisysteM langerhans cell histiocytosis with advanced orbital ...

    African Journals Online (AJOL)

    East African Medical Journa Vol. 87 No. 10 October 2010. MultisysteM langerhans cell histiocytosis with advanced orbital involveMent: case report. J. Mccaffrey, department of paediatrics, blackpool victoria hospital, whinney heys road, blackpool, lancashire, uK,. Fy3 8nr bM bch, ba hons, c. rawlingson, department of ...

  16. The fascinating world of graph theory

    CERN Document Server

    Benjamin, Arthur; Zhang, Ping

    2015-01-01

    Graph theory goes back several centuries and revolves around the study of graphs-mathematical structures showing relations between objects. With applications in biology, computer science, transportation science, and other areas, graph theory encompasses some of the most beautiful formulas in mathematics-and some of its most famous problems. The Fascinating World of Graph Theory explores the questions and puzzles that have been studied, and often solved, through graph theory. This book looks at graph theory's development and the vibrant individuals responsible for the field's growth. Introducin

  17. High expression of markers of apoptosis in Langerhans cell histiocytosis

    DEFF Research Database (Denmark)

    Petersen, Bodil Laub; Lundegaard, Pia Rengtved; Bank, M I

    2003-01-01

    AIMS: Langerhans cell histiocytosis is a rare disease with clonal proliferation of dendritic histiocytes, occurring most frequently in infancy and early childhood. In the localized form (single system), the disease is self-limiting, but in the cases of multisystem disease a third of the patients...... develop organ dysfunction. In these cases the prognosis is poor. Our objective has been to study the immunohistochemical expression of Fas and Fas-ligand (Fas-L) in order to determine whether the level of expression of these proteins could predict the outcome of the disease. We also wanted to determine......53 and the number of cells in apoptosis detected with TUNEL. Langerhans cell histiocytosis cells showed strong expression of p53 and in some cases co-expression of Fas and Fas-L. The expression of Fas-L was significantly higher in infiltrates from patients with single-system disease. The actual...

  18. Cerebellar and basal ganglion involvement in Langerhans cell histiocytosis

    Energy Technology Data Exchange (ETDEWEB)

    Saatci, I.; Baskan, O.; Haliloglu, M.; Aydingoz, U. [Department of Radiology, Hacettepe University Hospital, Sihhiye 06100, Ankara (Turkey)

    1999-06-01

    Langerhans cell histiocytosis (LCH) is a disease of unknown cause characterised by proliferation of histiocytic granulomas in tissues; the primary cerebral manifestation is diabetes insipidus caused by hypothalamic infiltration. We present a patient in whom, except for the absence of high signal on T 1 weighting in the posterior pituitary, consistent with central diabetes insipidus, MRI showed no evidence of hypothalamic involvement by histiocytosis, despite the long duration of the disease. However, there was bilateral, symmetrical involvement of the cerebellum and globus pallidus in addition to a calvarial lesion. High signal in the cerebellar white matter on T 2-weighted images may represent demyelination, gliosis and cell loss, as previously reported on pathologic examination. (orig.) With 5 figs., 22 refs.

  19. New insights in lymphangioleiomyomatosis and pulmonary Langerhans cell histiocytosis

    Directory of Open Access Journals (Sweden)

    Olga Torre

    2017-09-01

    Full Text Available Lymphangioleiomyomatosis (LAM and pulmonary Langerhans cell histiocytosis (PLCH are rare diseases that lead to progressive cystic destruction of the lungs. Despite their distinctive characteristics, these diseases share several features. Patients affected by LAM or PLCH have similar radiological cystic patterns, a similar age of onset, and the possibility of extrapulmonary involvement. In this review, the recent advances in the understanding of the molecular pathogenesis, as well as the current and most promising biomarkers and therapeutic approaches, are described.

  20. Cytological diagnosis of Langerhans cell histiocytosis with cutaneous involvement

    OpenAIRE

    Chandekar, Sushama A; Shah, Vinaya B; Vikas Kavishwar

    2013-01-01

    Langerhans cell histiocytosis (LCH) is a rare disease affecting predominantly children. The course of the disease varies, from spontaneous resolution to a progressive multisystem disorder with organ dysfunction and potential life-threatening complications. Diagnosis of LCH is often difficult and may be delayed because of its rarity and especially so if it occurs with unusual presentation. Fine needle aspiration cytology of a 4 year old male child, a case of LCH is presented with a purpose of ...

  1. Puzzle histiocytosis (solitary mononuclear xanthogranuloma with LCH component. A case report*

    Directory of Open Access Journals (Sweden)

    Katarzyna Woszczyna-Mleczko

    2017-02-01

    Full Text Available We report a case of 40-year-old Caucasian man presented with an asymptomatic nodule localized on his arm. The puzzle histiocytosis composed of juvenile xanthogranuloma and Langerhans cell histiocytosis was diagnosed. The results of immunohistochemical studies confirm the dual character of histological texture of the lesion.

  2. Role of PET/CT in congenital histiocytosis

    Energy Technology Data Exchange (ETDEWEB)

    Udayasankar, Unni K. [Emory University School of Medicine, Department of Radiology, Atlanta, GA (United States); Alazraki, Adina L.; Simoneaux, Stephen F. [Emory University School of Medicine, Department of Radiology, Atlanta, GA (United States); Children' s Healthcare of Atlanta at Egleston, Department of Radiology, Atlanta, GA (United States)

    2010-12-15

    Congenital Langerhans cell histiocytosis (LCH) is a rare, but often severe, form of LCH. Although a more benign single-system congenital LCH has been described, most cases present as multisystem disease with poorer prognosis and are often treated with systemic chemotherapy. Imaging plays a central role in diagnosis, initial staging and assessment of treatment response. PET/CT is increasingly utilized for pediatric LCH. We report a unique case with PET/CT used as an imaging tool in staging and evaluating treatment response in congenital multisystem LCH. (orig.)

  3. Langerhans cell histiocytosis: An uncommon presentation, successfully treated by thalidomide

    Directory of Open Access Journals (Sweden)

    Mohammad Shahidi-Dadras

    2011-01-01

    Full Text Available Langerhans cell histiocytosis (LCH is a rare disease and generally affects children under 15 years of age. Adult onset form and cutaneous features at presentation are uncommon. There are some options for treatment of the skin lesions of LCH such as topical and intralesional corticosteroid, nitrogen mustard, etc., which are not completely curative. Herein, we report a case of perianal LCH in a 20-year-old man with one-year history of recalcitrant well-demarcated, erythematous, and ulcerated plaque surrounding the anal orifice, with pain and difficulty in defecation that was successfully treated with thalidomide.

  4. Nodal Langerhans cell histiocytosis with prominent eosinophilic emperipolesis.

    Science.gov (United States)

    Chougule, Abhijit; Srivastava, Shreya; Totadri, Sidharth; Srinivasan, Radhika; Trehan, Amita

    2015-12-01

    Multinucleated giant cells of osteoclastic type are known to occur in nodal and extranodal lesions of Langerhans cell histiocytosis (LCH). These giant cells are thought to be derived from phagocytic histiocytes, which correlate with the degree of necrosis in LCH lesions. Emperipolesis commonly seen in Rosai-Dorfman disease is a distinct phenomenon characterized by intact phagocytosed cells in an intracytoplasmic vacuole protected from proteolytic digestion. We present a case of emperipolesis of inflammatory cells especially of eosinophils by multinucleated giant cells of Langhans type in a lymph node involved by LCH--a finding that has not been described previously in the literature. © 2015 Wiley Periodicals, Inc.

  5. Congenital self-healing histiocytosis presenting as blueberry muffin baby: A case report and literature review

    Directory of Open Access Journals (Sweden)

    Svetlana Popadic

    2012-01-01

    Full Text Available Congenital self-healing Langerhans cell histiocytosis (CSHLCH, also called as Hashimoto-Pritzker disease, is a rare, benign variant of histiocytosis. Despite the initial dramatic clinical presentation, affected infants are otherwise healthy and skin lesions disappear spontaneously within several weeks to months. We present a case of CSHLCH presenting as blueberry muffin baby. The lesions appeared in the first week of life and lasted 6 months. The follow-up period was 24 months, without any signs of relapse. At the pediatric dermatology unit of our clinic, during the last 20 years, we had 10 children with Langerhans cell histiocytosis and among them only one with CSHLCH. In the literature, we found only 5 newborns with Langerhans cell histiocytosis presenting as blueberry muffin baby, among them only 4 with self-healing CSHLCH. The early recognition of CSHLCH may spare children from redundant and potentially toxic systemic treatment.

  6. Clinical and radiological evolution in patients with pulmonary Langerhans' cell histiocytosis

    NARCIS (Netherlands)

    Westerlaan, HE; van der Valk, PDLPM

    Background: Pulmonary Langerhans' cell histiocytosis (LCH) is a diffuse, smoking-related lung disease characterised pathologically by proliferation of abnormal Langerhans' cells, cyst formation and vascular abnormalities, and physiologically by a decreased diffusing capacity. The aim of this study

  7. Fascinating Organic Transformations: Rational Mechanistic Analysis

    Indian Academy of Sciences (India)

    A natural property of an electron deficient centre is to make the system dynamic, thus opening the possibilities for charge dissipa- tion. This can be illustrated with what is called the Grotus mechanism (Figure 2). One can see how effectively the proton excess on the left side is transmitted by the medium to the right. Similarly ...

  8. Pulmonary langerhans cell histiocytosis case with diabetes insipidus and tuberculosis.

    Science.gov (United States)

    Ugurlu, E; Altinisik, G; Aydogmus, U; Bir, F

    2017-04-01

    A 19-year-old male patient was observed due to having central diabetes insipidus (DI) for five years. He had a history of smoking 5-10 cigarettes a day for two years, but stopped smoking from the last month. The computerized tomography revealed thin-walled cystic lesions in different sizes more dominantly in the upper lobes and consolidated areas in the left upper and lower lobes. The wedge resection from the right lower lobe revealed pulmonary langerhans cell histiocytosis. Follow-up acid-fast bacteria (AFB) examinations revealed (+++) and antituberculous treatment was started. On the 40th day of the anti-tuberculosis treatment, the patient applied once again due to fever and chest pain. Although infiltrations persisted in the left upper and middle zones in the postero-anterior lung rontgenogram, right-sided pneumothorax was detected. The case is considered tuberculosis and the patient continued to receive anti-TB treatment under the close supervision.

  9. Cytological diagnosis of Langerhans cell histiocytosis with cutaneous involvement

    Science.gov (United States)

    Chandekar, Sushama A; Shah, Vinaya B; Kavishwar, Vikas

    2013-01-01

    Langerhans cell histiocytosis (LCH) is a rare disease affecting predominantly children. The course of the disease varies, from spontaneous resolution to a progressive multisystem disorder with organ dysfunction and potential life-threatening complications. Diagnosis of LCH is often difficult and may be delayed because of its rarity and especially so if it occurs with unusual presentation. Fine needle aspiration cytology of a 4 year old male child, a case of LCH is presented with a purpose of highlighting the characteristic cytological features. A high index of suspicion, awareness of characteristic cytological features of LCH and its differential diagnoses is necessary. This can obviate the need of biopsy and electron microscopy. Immunohistochemistry if available can be performed on cytology smear and cell block. PMID:23661952

  10. Cytological diagnosis of Langerhans cell histiocytosis with cutaneous involvement

    Directory of Open Access Journals (Sweden)

    Sushama A Chandekar

    2013-01-01

    Full Text Available Langerhans cell histiocytosis (LCH is a rare disease affecting predominantly children. The course of the disease varies, from spontaneous resolution to a progressive multisystem disorder with organ dysfunction and potential life-threatening complications. Diagnosis of LCH is often difficult and may be delayed because of its rarity and especially so if it occurs with unusual presentation. Fine needle aspiration cytology of a 4 year old male child, a case of LCH is presented with a purpose of highlighting the characteristic cytological features. A high index of suspicion, awareness of characteristic cytological features of LCH and its differential diagnoses is necessary. This can obviate the need of biopsy and electron microscopy. Immunohistochemistry if available can be performed on cytology smear and cell block.

  11. Langerhans Cell Histiocytosis of the Clavicle in a 13-Year-Old Boy

    Directory of Open Access Journals (Sweden)

    Shital N. Parikh

    2014-01-01

    Full Text Available Langerhans Cell Histiocytosis (LCH is a rare neoplasm characterized by abnormal proliferation of histiocytic cells. In this case report, we describe a unique case of a 13-year-old boy who presented to the clinic with an insidious onset of mid-clavicular pain. The provisional radiologic diagnosis of Langerhans Cell Histiocytosis of the clavicle was confirmed by an incisional biopsy of the left mid-clavicle lesion. The patient’s lesion was treated by curettage, bone grafting, and internal fixation, due to the presence of pathologic fracture. At the 2-year followup, the patient was asymptomatic, and the lesion showed complete resolution without recurrence. The case report highlights the characteristic features of Langerhans Cell Histiocytosis in an unusual location, the knowledge of which would help avoid delayed or missed diagnosis in the future.

  12. Refresher Course on Water: Its Fascinating Science and Diverse ...

    Indian Academy of Sciences (India)

    IAS Admin

    2015-09-30

    Sep 30, 2015 ... chemistry, to its roles in biological, atmospheric, environmental contexts, and as a centrally important natural resource, is thus both fascinating and an ... water: Issues and nanotechnology solutions, water management and harvesting, water in the solar system and space. Lecturers: Roddam Narasimha ...

  13. Langerhans Cell Histiocytosis: A Diagnostic Challenge in the Oral Cavity

    Directory of Open Access Journals (Sweden)

    Mehmet Ali Altay

    2017-01-01

    Full Text Available Background. Langerhans cell histiocytosis (LCH is a rare disorder of the reticuloendothelial system with unknown etiology. This report aims to present a case of LCH with diffuse involvement of the oral cavity and to raise awareness of the distinguishing features of this diagnostically challenging entity. Case Report. A 26-year-old male patient presented with complaints of teeth mobility, intense pain, and difficulty in chewing. Intraoral and radiological examinations revealed generalized gingival hyperplasia and severe teeth mobility with widespread alveolar bone loss. Periodontal therapy was performed with no significant improvement. An incisional biopsy revealed Langerhans cells and positive reaction to S-100 and CD1, and the patient was diagnosed with LCH. The patient underwent systemic chemotherapy with vinca alkaloids and corticosteroids. Regression of gingival lesions, as well as significant decrease in mobility of the remaining teeth and severity of pain, was achieved during 12 months of follow-up. Conclusion. The rarity and variable system involvement of LCH necessitate a multidisciplinary approach be carried out for accurate diagnosis, effective treatment, and an uneventful follow-up. Awareness of oral manifestations of LCH may aid clinicians greatly in reducing morbidity and mortality associated with this debilitating condition.

  14. [Secondary biliary cirrhosis in a patient with histiocytosis X].

    Science.gov (United States)

    Romão, Zita; Pontes, J; Andrade, P; Leitão, M C; Donato, A; Freitas, Diniz

    2002-01-01

    Histiocitose X or Histiocytosis of the Langerhans cells represents a complex spectrum of clinical alterations, resulting from infiltration by anomalous histiocytes of various organs, including the skin, bones, lungs, lymphatic ganglia and liver. Liver disease is rare and the mechanism by which lesions appear is unknown. Cholestasis results from phenomena of sclerosant colangitis, which affects the intrahepatic ducts, or from proliferation of histiocytic cells in the periportal areas. Some patients develop biliar cyrrhosis. The authors present the clinical case of a 62-year-old female patient, hospitalized for chronic cholestasis, diabetes and gallstone in the main bile duct. She had metastatic lesions of the hypophysis and bones, the biopsies of which revealed infiltration by histiocytic cells. Endoscopic Retrograde Colangiopancreatography (E.R.C.P.) revealed dilatation of intrahepatic bile ducts and stenosis of left hepatic duct. A histological study of the hepatic biopsy showed chronic cholestasis and areas of fibrosis, without infiltration by histiocytic granulomas, which were observed in the medular biopsy and in the thyroid nodule cytology.

  15. Disseminated Langerhans' cell histiocytosis and massive protein-losing enteropathy

    Directory of Open Access Journals (Sweden)

    Santos-Machado T.M.

    1999-01-01

    Full Text Available Symptomatic involvement of the gastrointestinal (GI tract as a prominent symptom in Langerhans' cell histiocytosis (LCH is uncommon, occurring in less than 1 to 5% of all cases, even when the disease is in its disseminated form. Up to now, there have been reports of 18 cases of LCH with GI manifestations, including our 2 cases, with diarrhea (77.7%, protein-losing enteropathy (33.3% and bloody stool being the most frequent findings. The authors present two patients with severe diarrhea and refractory hypoalbuminemia, and with the protein-losing enteropathy documented by Cr51-labeled albumin studies. A review of the literature indicated that the presence of GI symptoms is often associated with systemic disease as well as with poor prognosis, mainly under 2 years of age. Radioisotopes are useful for documenting protein loss in several diseases with high specificity and sensitivity, and their utilization in the cases reviewed here permitted diagnoses in 6 children, as well as improved therapeutic management.

  16. Pulmonary Langerhans Cell Histiocytosis: An Update From the Pathologists' Perspective.

    Science.gov (United States)

    Roden, Anja C; Yi, Eunhee S

    2016-03-01

    Pulmonary Langerhans cell histiocytosis (PLCH) is a rare histiocytic disorder that almost exclusively affects the lungs of smokers. PLCH is characterized by bronchiolocentric nodules and/or cysts in an upper and mid lung distribution with sparing of the costophrenic angles. The diagnosis can be challenging and often requires transbronchial biopsy or surgical lung biopsy. Pulmonary hypertension is a relatively common and sometimes severe complication of PLCH. The pathogenesis of PLCH is still debated. Recently, BRAF V600E mutation and BRAF expression have been identified in some patients with PLCH, suggesting that at least a subset of PLCH has a clonal proliferation. While smoking cessation is the first-line treatment of PLCH, some patients might require additional treatment and eventually transplant. Given that the lesional cells of PLCH express BRAF in some patients, MAPKinase pathway-targeted treatment might be useful for therapy-resistant patients. To present the more recently recognized clinical and pathologic aspects of PLCH, including pulmonary hypertension in PLCH, pathogenesis, and treatment, as well as the basic diagnostic approach to PLCH. Authors' own research, and search of literature database (PubMed) and UpToDate. Despite the recent progress, more studies are needed to elucidate the biology of PLCH for identification of prognostic factors and appropriate treatment options, especially for therapy-refractory PLCH cases.

  17. Aspecific inflammatory lesion (histiocytosis?) simulating intramedullary astrocytoma. Case report.

    Science.gov (United States)

    Palma, L; Rizzo, G; Lio, R; Mariottini, A; Mazzocchio, R

    1999-03-01

    We report an exceptional case of aspecific inflammatory lesion of the thoracic spinal cord simulating an intramedullary glial tumor. Patient history was characterized by progressive spastic paraparesis with urinary incontinence; MR imaging (T4-T5) showed an enhancing intrinsic mass lesion. Myelotomy enabled partial resection of grayish astrocytoma-like tissue. Only light microscope examination was possible and disclosed aspecific inflammatory tissue composed of eosinophils, lymphocytes and histiocytes. After the operation, the patient improved promptly and no further therapy was administered. Control MRI after four months, one year and two years showed complete disappearance of the intramedullary mass lesion and the patient remained clinically stable with no other signs of disease. Since electron microscopic as well as immunohistochemical studies were not available, a definitive histological diagnosis was not possible. However on the basis of some clinical similarities with cases of isolated histiocytosis X of the CNS reported in the literature, we suggest that a diagnosis of isolated intramedullary eosinophilic granuloma could be reasonable.

  18. Langerhans' cell histiocytosis presenting with an intracranial epidural hematoma

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K.-W. [Department of Pediatrics, Loma Linda Children' s Hospital and University Medical Center, Loma Linda, CA (United States); McLeary, M.S. [Div. of Pediatric Radiology, Loma Linda Children' s Hospital and University Medical Center, Loma Linda, CA (United States); Zuppan, C.W. [Dept. of Pathology, Loma Linda Children' s Hospital and University Medical Center, Loma Linda, CA (United States); Won, D.J. [Div. of Pediatric Neurosurgery, Loma Linda University Children' s Hospital, Loma Linda, CA (United States)

    2000-05-01

    An 8-year-old boy developed vomiting and severe headache following minor head trauma. A CT scan of the head demonstrated a lytic lesion of the skull and adjacent epidural hematoma. Surgical evacuation and removal of the skull lesion and hematoma were carried out, and pathologic evaluation resulted in a diagnosis of Langerhans' cell histiocytosis (LCH). Epidural involvement of Langerhans' cell histiocytosis is very rare, and we report the first case of LCH presenting as an intracranial epidural hematoma. (orig.)

  19. Unusual location of central nervous system langerhans cell histiocytosis: case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, E. Yup; Lee, Jae Kyu; Kim, Chan Kyo; Lee, Chang Hyun; Kang, Chang Ho; Chung, Phil Wook [Armed Forces Capital Hospital, Seongnam (Korea, Republic of)

    2003-03-01

    Langerhans cell histiocytosis of the central nervous system (CNS) usually involves the hypothalamic-pituitary axis, and T1-weighted MR images normally demonstrate infundibular thickening and/or a mass lesion in the hypothalamus and the absence of a posterior pituitary 'bright spot'. We recently encountered a case of CNS langerhans cell histiocytosis with no posterior pituitary 'bright spot' and with lesions involving the cerebellum and basal ganglia but not the hypothalamic-pituitary axis.

  20. Fascination violence: on mind and brain of man hunters.

    Science.gov (United States)

    Elbert, Thomas; Weierstall, Roland; Schauer, Maggie

    2010-11-01

    Why are savagery and violence so omnipresent among humans? We suggest that hunting behaviour is fascinating and attractive, a desire that makes temporary deprivation from physical needs, pain, sweat, blood and, ultimately, the willingness to kill tolerable and even appetitive. Evolutionary development into the "perversion" of the urge to hunt humans, that is to say the transfer of this hunt to members of one's own species, has been nurtured by the resultant advantage of personal and social power and dominance. While a breakdown of the inhibition towards intra-specific killing would endanger any animal species, controlled inhibition was enabled in humans in that higher regulatory systems, such as frontal lobe-based executive functions, prevent the involuntary derailment of hunting behaviour. If this control--such as in child soldiers for example--is not learnt, then brutality towards humans remains fascinating and appealing. Blood must flow in order to kill. It is hence an appetitive cue as is the struggling of the victim. Hunting for men, more rarely for women, is fascinating and emotionally arousing with the parallel release of testosterone, serotonin and endorphins, which can produce feelings of euphoria and alleviate pain. Bonding and social rites (e.g. initiation) set up the constraints for both hunting and violent disputes. Children learn which conditions legitimate aggressive behaviour and which not. Big game hunting as well as attack of other communities is more successful in groups--men also perceive it as more pleasurable. This may explain the fascination with gladiatorial combat, violent computer games but as well ritualized forms like football.

  1. New methods for assessing the fascinating nature of nature experiences.

    Directory of Open Access Journals (Sweden)

    Yannick Joye

    Full Text Available In recent years, numerous environmental psychology studies have demonstrated that contact with nature as opposed to urban settings can improve an individual's mood, can lead to increased levels of vitality, and can offer an opportunity to recover from stress. According to Attention Restoration Theory (ART the restorative potential of natural environments is situated in the fact that nature can replenish depleted attentional resources. This replenishment takes place, in part, because nature is deemed to be a source of fascination, with fascination being described as having an "attentional", an "affective" and an "effort" dimension. However, the claim that fascination with nature involves these three dimensions is to a large extent based on intuition or derived from introspection-based measurement methods, such as self-reports. In three studies, we aimed to more objectively assess whether these three dimensions indeed applied to experiences related to natural environments, before any (attentional depletion has taken place. The instruments that were used were: (a the affect misattribution procedure (Study 1, (b the dot probe paradigm (Study 2 and (c a cognitively effortful task (Study 3. These instrument were respectively aimed at verifying the affective, attentional and effort dimension of fascination. Overall, the results provide objective evidence for the claims made within the ART framework, that natural as opposed to urban settings are affectively positive (cfr., affective dimension and that people have an attentional bias to natural (rather than urban environments (cfr., attentional dimension. The results regarding the effort dimension are less straightforward, and suggest that this dimension only becomes important in sufficiently difficult cognitive tasks.

  2. New methods for assessing the fascinating nature of nature experiences.

    Science.gov (United States)

    Joye, Yannick; Pals, Roos; Steg, Linda; Evans, Ben Lewis

    2013-01-01

    In recent years, numerous environmental psychology studies have demonstrated that contact with nature as opposed to urban settings can improve an individual's mood, can lead to increased levels of vitality, and can offer an opportunity to recover from stress. According to Attention Restoration Theory (ART) the restorative potential of natural environments is situated in the fact that nature can replenish depleted attentional resources. This replenishment takes place, in part, because nature is deemed to be a source of fascination, with fascination being described as having an "attentional", an "affective" and an "effort" dimension. However, the claim that fascination with nature involves these three dimensions is to a large extent based on intuition or derived from introspection-based measurement methods, such as self-reports. In three studies, we aimed to more objectively assess whether these three dimensions indeed applied to experiences related to natural environments, before any (attentional) depletion has taken place. The instruments that were used were: (a) the affect misattribution procedure (Study 1), (b) the dot probe paradigm (Study 2) and (c) a cognitively effortful task (Study 3). These instrument were respectively aimed at verifying the affective, attentional and effort dimension of fascination. Overall, the results provide objective evidence for the claims made within the ART framework, that natural as opposed to urban settings are affectively positive (cfr., affective dimension) and that people have an attentional bias to natural (rather than urban) environments (cfr., attentional dimension). The results regarding the effort dimension are less straightforward, and suggest that this dimension only becomes important in sufficiently difficult cognitive tasks.

  3. New Methods for Assessing the Fascinating Nature of Nature Experiences

    Science.gov (United States)

    Joye, Yannick; Pals, Roos; Steg, Linda; Evans, Ben Lewis

    2013-01-01

    In recent years, numerous environmental psychology studies have demonstrated that contact with nature as opposed to urban settings can improve an individual’s mood, can lead to increased levels of vitality, and can offer an opportunity to recover from stress. According to Attention Restoration Theory (ART) the restorative potential of natural environments is situated in the fact that nature can replenish depleted attentional resources. This replenishment takes place, in part, because nature is deemed to be a source of fascination, with fascination being described as having an “attentional”, an “affective” and an “effort” dimension. However, the claim that fascination with nature involves these three dimensions is to a large extent based on intuition or derived from introspection-based measurement methods, such as self-reports. In three studies, we aimed to more objectively assess whether these three dimensions indeed applied to experiences related to natural environments, before any (attentional) depletion has taken place. The instruments that were used were: (a) the affect misattribution procedure (Study 1), (b) the dot probe paradigm (Study 2) and (c) a cognitively effortful task (Study 3). These instrument were respectively aimed at verifying the affective, attentional and effort dimension of fascination. Overall, the results provide objective evidence for the claims made within the ART framework, that natural as opposed to urban settings are affectively positive (cfr., affective dimension) and that people have an attentional bias to natural (rather than urban) environments (cfr., attentional dimension). The results regarding the effort dimension are less straightforward, and suggest that this dimension only becomes important in sufficiently difficult cognitive tasks. PMID:23922645

  4. Adult Langerhans cell histiocytosis presenting as metachronous colonic polyps

    Directory of Open Access Journals (Sweden)

    Aloísio Felipe-Silva

    2013-03-01

    Full Text Available Langerhans cell histiocytosis (LCH is a rare disease characterized by proliferation of Langerhans-type cells that express CD1a, Langerin (CD207 and S100 protein. Birbeck granules are a hallmark by ultrastructural examination. LCH presents with a wide clinical spectrum, ranging from solitary lesions of a single site (usually bone or skin to multiple or disseminated multisystemic lesions, which can lead to severe organ dysfunction. Most cases occur in children. Gastrointestinal tract involvement is rare and has been associated with systemic illness and poor prognosis especially in children under the age of 2 years. Adult gastrointestinal LCH is very rare. We report a case of a previously healthy, nonsmoking 48-year-old male who was referred for routine screening colonoscopy. Two sessile, smooth, firm and yellowish LCH polyps measuring 0.2 cm and 0.3 cm were detected in the sigmoid colon. Fifteen months later a second colonoscopy found two histologically confirmed hyperplastic polyps at the sigmoid colon. No other LCH lesions were seen. A third colonoscopy after 28 months of follow-up found a submucosal 0.5 cm infiltrated and ulcerated LCH polyp in the cecum, close to the ostium of the appendix. The patient had been asymptomatic for all this period. Imaging investigation for systemic or multiorgan disease did not find any sign of extracolonic involvement. On histology all lesions showed typical LCH features and immunohistochemical analysis showed strong and diffuse staining for CD1a and CD207. This case illustrates two distinct clinicopathologic features not previously reported in this particular clinical setting: metachronous colonic involvement and positivity for CD207.

  5. Early Diagnosis and Monitoring of Neurodegenerative Langerhans Cell Histiocytosis.

    Directory of Open Access Journals (Sweden)

    Elena Sieni

    Full Text Available Neurodegenerative Langerhans Cell Histiocytosis (ND-LCH is a rare, unpredictable consequence that may devastate the quality of life of patients cured from LCH. We prospectively applied a multidisciplinary diagnostic work-up to early identify and follow-up patients with ND-LCH, with the ultimate goal of better determining the appropriate time for starting therapy.We studied 27 children and young adults with either ND-LCH verified by structural magnetic resonance imaging (MRI (group 1 or specific risk factors for (diabetes insipidus, craniofacial bone lesions, but no evidence of, neurodegenerative MRI changes (group 2. All patients underwent clinical, neurophysiological and MRI studies.Seventeen patients had MRI alterations typical for ND-LCH. Nine showed neurological impairment but only three were symptomatic; 11 had abnormal somatosensory evoked potentials (SEPs, and five had abnormal brainstem auditory evoked potentials (BAEPs. MR spectroscopy (MRS showed reduced cerebellar NAA/Cr ratio in nine patients. SEPs showed sensitivity, specificity, positive predictive value (PPV and negative predictive value (NPV for predicting ND-LCH of 70.6% (95%CI, 44.0%-89.7%, 100% (69.2%-100%, 100% (73.5%-100%, and 66.7% (38.4%-88.2%, respectively. Repeated investigations in group 1 revealed increasingly abnormal EP parameters, or neurological examination, or both, in nine of fifteen patients while MRI remained unchanged in all but one patient.A targeted MRI study should be performed in all patients with risk factors for ND-LCH for early identification of demyelination. The combined use of SEPs and careful neurological evaluation may represent a valuable, low-cost, well-tolerated and easily available methodology to monitor patients from pre-symptomatic to symptomatic stages. We suggest a multidisciplinary protocol including clinical, MRS, and neurophysiological investigations to identify a population target for future therapeutic trials.

  6. Neuropsychologic deficits in children with Langerhans cell histiocytosis.

    Science.gov (United States)

    Whitsett, S F; Kneppers, K; Coppes, M J; Egeler, R M

    1999-11-01

    Manifestations of Langerhans cell histiocytosis (LCH) in children range from only a rash, to bony lesions accompanied by pain, to major organ disease. When the central nervous system (CNS) is affected, the LCH patient may exhibit signs and symptoms of hypothalamic and pituitary dysfunction (most often resulting in diabetes insipidus or other endocrinopathies) or more global neurologic and neuropsychologic sequelae. Surprisingly, researchers have only recently begun to examine the neuropsychologic manifestations of the disease, but early findings suggest that they may, in fact, be significant in a small percentage of children with LCH. We evaluated two CNS-positive patients with LCH and long-term intermittent treatments, using extensive neuropsychologic assessments, including intellectual functioning, memory, visual-motor functioning, attention and concentration, sensory and motor performance, and gross academic achievement. Objective measures of behavior were obtained through parental report. Neuroradiologic imaging was obtained concurrently with the neuropsychologic evaluations. The neuropsychologic assessments indicated significant deficits in a number of the measured areas of functioning. Global cognitive deficiencies in full-scale IQ were identified, as were deficits in memory, attention/concentration, and perceptual-organizational capabilities. Similarities were noted in the patterns of deficits obtained with both patients, despite differences in the pathophysiology of their disease. Behavioral functioning in both children had suffered, presumably in relation to the neuropsychologic deficits. There were radiologic findings of gross cerebellar white matter damage in one patient, in addition to focal (e.g., hypothalamic) lesions in the other. LCH has an adverse impact on cognitive functions in some children with evidence of CNS involvement, and further study into the etiology, incidence, and means of remedial intervention is needed. Copyright 1999 Wiley

  7. BISPHOSPHONATES IN LANGERHANS CELL HISTIOCYTOSIS: AN INTERNATIONAL RETROSPECTIVE CASE SERIES

    Directory of Open Access Journals (Sweden)

    Deepak Chellapandian

    2016-07-01

    Full Text Available Background: Bone is the most common organ of involvement in patients with Langerhans cell histiocytosis (LCH, which is often painful and associated with significant morbidity from pathological fractures. Current first-line treatments include chemotherapy and steroids that are effective but often associated with adverse effects, whereas the disease may reactivate despite an initial response to first-line agents. Bisphosphonates are osteoclast inhibitors that have shown to be helpful in treating bone lesions of LCH. To date, there are no large international studies to describe their role in treating bone lesions of LCH. Method: We conducted a multicenter retrospective review of 13 patients with histologically proven LCH, who had received bisphosphonates either at diagnosis or at disease reactivation. Results: Ten patients (77% had a single system bone disease, and 3 (23% had bone lesions as part of multisystem disease. Median follow-up time post-bisphosphonate therapy was 4.6 years (range, 0.8 to 8.2 years. Treatment with bisphosphonates was associated with significant pain relief in almost all patients. Twelve  (92% achieved resolution of active bone lesions, and 10 out of them had no active disease for a median of 3.5 years (range, 0.8 to 5 years. One patient did not respond. No major adverse effects were reported in this series.  Conclusion: Bisphosphonates are well-tolerated drugs that can significantly improve bone pain and induce remission in active bone LCH. Future prospective studies evaluating the role of bisphosphonates in LCH are warranted.

  8. Pulmonary Langerhans cell histiocytosis and diabetes insipidus in pregnant women: our experience.

    Science.gov (United States)

    Fuks, Leonardo; Kramer, Mordechai R; Shitrit, David; Raviv, Yael

    2014-04-01

    Pulmonary Langerhans cell histiocytosis (PLCH) occurs predominantly in young adult smokers. Diabetes insipidus occurs in up to 15 % patients with PLCH. Information on PLCH in pregnancy is sparse, especially associated with diabetes insipidus. We report three patients with these conditions and describe the disease history and pregnancy outcomes.

  9. Diagnosis of Primary Langerhans Cell Histiocytosis of the Vulva in a Postmenopausal Woman

    Directory of Open Access Journals (Sweden)

    Sefa Kurt

    2013-01-01

    Full Text Available Langerhans cell histiocytosis (LCH is a very rare disease of female genital tract, most commonly seen in vulva and unusual in postmenopausal period. Herein, we report the 8th case of pure vulvar LCH in a postmenopausal woman. We pay attention to the differential diagnosis in postmenopausal state, features of pathologic diagnosis, and treatment options.

  10. Central diabetes insipidus: Is it Langerhans cell histiocytosis of the pituitary stalk? A diagnostic pitfall.

    NARCIS (Netherlands)

    Prosch, H.; Grois, N.; Bökkerink, J.P.M.; Prayer, D.; Leuschner, I.; Minkov, M.; Gadner, H.

    2006-01-01

    Central diabetes insipidus (CDI) is a rare disorder that may be caused by a variety of diseases. In pediatric and adolescent patients the most common causes for CDI are Langerhans cell histiocytosis (LCH) and germinoma. To avoid a potentially hazardous biopsy of the hypothalamic pituitary region it

  11. Melanotic paraganglioma arising in the temporal horn following Langerhans cell histiocytosis

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jeong Hyun [Baylor College of Medicine, Neuroradiology Department, Houston, TX (United States); Ewha Womans University, Radiology Department, School of Medicine, Seoul (Korea); Rivera, Andreana [Baylor College of Medicine, Pathology Department, Houston, TX (United States); Naeini, Ramin M.; Yedururi, Sireesha; Megahead, Hatem [Baylor College of Medicine, Radiology Department, Houston, TX (United States); Bayindir, Petek [Ege Universitesi, Radiology Department, Lojmanlari (Turkey); Fuller, Gregory N. [MD Anderson Cancer Center, Pathology Department, Houston, TX (United States); Suh, Jeong Soo [Ewha Womans University, Radiology Department, School of Medicine, Seoul (Korea); Adesina, Adekunle M. [Baylor College of Medicine, Pathology Department, Houston, TX (United States); Texas Children' s Cancer Center, Houston, TX (United States); Hunter, Jill V. [Texas Children' s Cancer Center, Houston, TX (United States); Baylor College of Medicine, Neuroradiology Department, Houston, TX (United States)

    2008-05-15

    Intracerebral paragangliomas are rare because of the lack of paraganglial cells in the cerebral tissue. We report a rare case of melanotic paraganglioma arising from the temporal horn of the lateral ventricle in a patient with prior Langerhans cell histiocytosis (LCH) treated with chemotherapy and radiation. (orig.)

  12. Maturation of Howell-Jolly bodies observed in a case of malignant histiocytosis.

    Science.gov (United States)

    Tatsumi, N; Tsuda, I; Matsumoto, H

    1988-01-01

    The maturation of Howell-Jolly bodies was microscopically observed on the May-Grünwald-Giemsa-stained film of bone marrow obtained from a patient with malignant histiocytosis. The bodies separated from the nucleus at the polychromatophilic normoblast stage and condensed faster than the main nucleus before denucleation in the normoblast stage.

  13. Mutations in SLC29A3, encoding an equilibrative nucleoside transporter ENT3, cause a familial histiocytosis syndrome (Faisalabad histiocytosis and familial Rosai-Dorfman disease.

    Directory of Open Access Journals (Sweden)

    Neil V Morgan

    2010-02-01

    Full Text Available The histiocytoses are a heterogeneous group of disorders characterised by an excessive number of histiocytes. In most cases the pathophysiology is unclear and treatment is nonspecific. Faisalabad histiocytosis (FHC (MIM 602782 has been classed as an autosomal recessively inherited form of histiocytosis with similarities to Rosai-Dorfman disease (RDD (also known as sinus histiocytosis with massive lymphadenopathy (SHML. To elucidate the molecular basis of FHC, we performed autozygosity mapping studies in a large consanguineous family and identified a novel locus at chromosome 10q22.1. Mutation analysis of candidate genes within the target interval identified biallelic germline mutations in SLC29A3 in the FHC kindred and in two families reported to have familial RDD. Analysis of SLC29A3 expression during mouse embryogenesis revealed widespread expression by e14.5 with prominent expression in the central nervous system, eye, inner ear, and epithelial tissues including the gastrointestinal tract. SLC29A3 encodes an intracellular equilibrative nucleoside transporter (hENT3 with affinity for adenosine. Recently germline mutations in SLC29A3 were also described in two rare autosomal recessive disorders with overlapping phenotypes: (a H syndrome (MIM 612391 that is characterised by cutaneous hyperpigmentation and hypertrichosis, hepatomegaly, heart anomalies, hearing loss, and hypogonadism; and (b PHID (pigmented hypertrichosis with insulin-dependent diabetes mellitus syndrome. Our findings suggest that a variety of clinical diagnoses (H and PHID syndromes, FHC, and familial RDD can be included in a new diagnostic category of SLC29A3 spectrum disorder.

  14. Intracranial non-Langerhans cell histiocytosis presenting as an isolated intraparenchymal lesion

    Energy Technology Data Exchange (ETDEWEB)

    Rajaram, Smitha; Shackley, Fiona; Raghavan, Ashok [Western Bank, Sheffield Children' s Hospital, Sheffield (United Kingdom); Wharton, Stephen B. [University of Sheffield, Department of Neurosciences, Sheffield (United Kingdom); Connolly, Daniel J.A. [Western Bank, Sheffield Children' s Hospital, Sheffield (United Kingdom); University of Sheffield, Academic Radiology, Sheffield (United Kingdom)

    2010-12-15

    Non-Langerhans cell histiocytosis in the absence of cutaneous or other organ involvement is very rare. A Caucasian boy age 3 years 11 months presented with episodes of recurrent right-side seizures over 2 weeks. Brain CT and MR imaging showed a single enhancing left frontal lobe lesion. Stereotactic biopsy was performed and histological examination showed diffuse infiltrate of macrophages with foamy cytoplasm. Four months later there was recurrence of seizure activity despite anti-epileptic medication and a repeat MR scan showed a persistent enhancing lesion in the left frontal lobe. Histological examination of the resection specimen resembled juvenile xanthogranuloma (JXG) involving the central nervous system. In the absence of skin lesions a diagnosis of non-Langerhans cell histiocytosis was made. The child made a full recovery following surgery with resolution of his symptoms. (orig.)

  15. Primary hypothyroidism, precocious puberty and hypothalamic obesity in Langerhans cell histiocytosis.

    Science.gov (United States)

    Priyambada, Leena; Bhatia, Vijayalakshmi; Krishnani, Narendra; Agarwal, Vinita; Bhattacharyya, Avik; Jain, Sunil; Mishra, S K; Marwaha, R K

    2011-03-01

    A 5 year old girl presented with central diabetes insipidus and primary hypothyroidism. No clinical or radiological evidence of Langerhans cell histiocytosis (LCH) was present. Absent posterior pituitary bright spot was seen in magnetic resonance imaging of the brain. She subsequently developed severe headache, massive obesity, accelerated growth and thelarche. A repeat MRI of the brain revealed hypothalamic tumor. Hormonal investigations revealed, paradoxically, undetectable growth hormone on a clonidine stimulation test. Langerhans cell histiocytosis was proved on electron microscopy of the thyroid tissue. There needs to be a high degree of suspicion for LCH as an etiology of primary hypothyroidism, especially in the presence of diabetes insipidus. Precocious puberty, accelerated growth despite growth hormone deficiency, hypothalamic obesity may occur in pediatric LCH. CNS lesions may have an evolving course, thus repeat neuroimaging is important.

  16. Primary cerebral non-Langerhans cell histiocytosis: MRI and differential diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Ernemann, U.; Skalej, M.; Voigt, K. [Department of Neuroradiology, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Hermisson, M.; Platten, M. [Department of Neurology, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Jaffe, R. [Pathology Department, Children' s Hospital of Pittsburgh, 3705 Fifth Avenue, Pittsburgh, PA 15213 (United States)

    2002-09-01

    We report a young woman with primary cerebral non-Langerhans cell histiocytosis of the juvenile xanthogranuloma family. The clinical course was complicated by extensive infiltration of cranial nerves and meninges and epi- and intramedullary spinal dissemination. Whereas the cutaneous form of juvenile xanthogranuloma is usually benign and self-limited, central nervous system involvement is associated with high morbidity and mortality and might therefore be considered a separate clinical entity. (orig.)

  17. Laryngeal Langerhans Cell Histiocytosis Presenting with Neck Mass in an Adult Woman

    Directory of Open Access Journals (Sweden)

    Hesam Jahandideh

    2016-01-01

    Full Text Available Langerhans cell histiocytosis (LCH is a very rare condition that commonly affects the head and neck region. There are very few cases of isolated laryngeal involvement by LCH, mostly reported in pediatric patients. Here, we report a case of laryngeal LCH in a 62-year-old woman presenting with a neck mass several weeks ago. The clinical and histopathological findings are reported with a brief discussion about the disease.

  18. Fascin 2b is a component of stereocilia that lengthens actin-based protrusions.

    Directory of Open Access Journals (Sweden)

    Shih-Wei Chou

    Full Text Available Stereocilia are actin-filled protrusions that permit mechanotransduction in the internal ear. To identify proteins that organize the cytoskeleton of stereocilia, we scrutinized the hair-cell transcriptome of zebrafish. One promising candidate encodes fascin 2b, a filamentous actin-bundling protein found in retinal photoreceptors. Immunolabeling of zebrafish hair cells and the use of transgenic zebrafish that expressed fascin 2b fused to green fluorescent protein demonstrated that fascin 2b localized to stereocilia specifically. When filamentous actin and recombinant fusion protein containing fascin 2b were combined in vitro to determine their dissociation constant, a K(d≈0.37 µM was observed. Electron microscopy showed that fascin 2b-actin filament complexes formed parallel actin bundles in vitro. We demonstrated that expression of fascin 2b or espin, another actin-bundling protein, in COS-7 cells induced the formation of long filopodia. Coexpression showed synergism between these proteins through the formation of extra-long protrusions. Using phosphomutant fascin 2b proteins, which mimicked either a phosphorylated or a nonphosphorylated state, in COS-7 cells and in transgenic hair cells, we showed that both formation of long filopodia and localization of fascin 2b to stereocilia were dependent on serine 38. Overexpression of wild-type fascin 2b in hair cells was correlated with increased stereociliary length relative to controls. These findings indicate that fascin 2b plays a key role in shaping stereocilia.

  19. Investigating the effects of green marketing on development of brand fascination

    Directory of Open Access Journals (Sweden)

    Hamed Abbasi

    2014-04-01

    Full Text Available This paper investigates the effects of different green marketing on brand fascination for a south Korean electronic producer, Samsung. The proposed study designs two questionnaires, one for measuring the effects of green marketing and the other for brand fascination in Likert scale. Cronbach alphas for green marketing and brand fascination are calculated as 0.72 and 0.79, respectively. The study has been implemented among 385 regular customers of Samsung’s electronic devices. Using Spearman correlation ratio as well as stepwise regression analysis, the study has concluded that two components of green marketing including green product and green promotion influence positively on brand fascination, positively.

  20. Myth polar light. Why sky bands, herring lightnings, and solar winds fascinate; Mythos Polarlicht. Warum Himmelsbaender, Heringsblitze und Sonnenwinde faszinieren

    Energy Technology Data Exchange (ETDEWEB)

    Hunnekuhl, Michael

    2014-07-01

    The actual state of knowledge of the polar-light research is in this illustrated volume as entertainingly as scientific-foundedly presented. The pecularities of pola lights beyond the polar-light zones as for instance in Germany are thematized and the conditions and periods, in which it there occurs, explained. Michael Hunnekuhl succeeds to mediate the fascination and emotion and simultaneously to explain the phenomena according to the latest state of science generally understandably. Which very old interpretations and descriptions are transmitted, which imaginations had men of polar lights long before the science could them explain? Hunnekuhl takes the reader along with into the world of legends and myths around the polar light. An experience report from the deeply snowed up wideness of Lapland lets everybody closely participate at a polar-light observation and feel the emotion, which it can fan. Above 70 polar-light pictures of high value and further explaining graphics show the continuously changing play of colors, supplement the explanations, and make the fascination comprehensible. Spectacular polar-light films from the international space station ISS, photographs from sun-observation satellites, as well as a polar-light film in real time are bound in the book via QR codes and make the time dimension and the dynamics of this fascinating natural spectacle alively comprehensible.

  1. Prostaglandins regulate nuclear localization of Fascin and its function in nucleolar architecture.

    Science.gov (United States)

    Groen, Christopher M; Jayo, Asier; Parsons, Maddy; Tootle, Tina L

    2015-05-15

    Fascin, a highly conserved actin-bundling protein, localizes and functions at new cellular sites in both Drosophila and multiple mammalian cell types. During Drosophila follicle development, in addition to being cytoplasmic, Fascin is in the nuclei of the germline-derived nurse cells during stages 10B-12 (S10B-12) and at the nuclear periphery during stage 13 (S13). This localization is specific to Fascin, as other actin-binding proteins, Villin and Profilin, do not exhibit the same subcellular distribution. In addition, localization of fascin1 to the nucleus and nuclear periphery is observed in multiple mammalian cell types. Thus the regulation and function of Fascin at these new cellular locations is likely to be highly conserved. In Drosophila, loss of prostaglandin signaling causes a global reduction in nuclear Fascin and a failure to relocalize to the nuclear periphery. Alterations in nuclear Fascin levels result in defects in nucleolar morphology in both Drosophila follicles and cultured mammalian cells, suggesting that nuclear Fascin plays an important role in nucleolar architecture. Given the numerous roles of Fascin in development and disease, including cancer, our novel finding that Fascin has functions within the nucleus sheds new light on the potential roles of Fascin in these contexts. © 2015 Groen et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  2. The concentration of il-1β in saliva of children with oral lesions associated to histiocytosis.

    Science.gov (United States)

    Benchuya, Carolina; Paván, Verónica; Gualtieri, Ariel; de Preliasco, Virginia Fernández

    2015-01-01

    Langerhans Cell Histiocytosis (LCH) is a disease whose etiology and pathogenesis are still unknown. It affects several organs and tissues, producing lesions of different severity. Its histopathology and clinical picture suggest the participation of cytokines in its pathogenesis. IL-1β might have an important role in its development. The purpose of this study was to determine the concentrations of IL-1β in saliva of pediatric patients diagnosed with LCH, with and without oral manifestations (Groups 1 and 2 respectively) compared to a Control Group (Group 3) of pediatric patients without medical antecedents or oral lesions. The saliva of twenty patients with LCH was studied and compared to a Control Group consisting of eleven pediatric patients without medical antecedents. The children with histiocytosis, aged four months to sixteen years, were referred by the Oncohaematology Service at Garrahan Hospital and Hospital de Clinicas, to the Department of Comprehensive Children's Dentistry, School of Dentistry, University of Buenos Aires (UBA). The concentrations of IL-1β in the different groups were determined using the Enzyme Immune Assay Kit (Cayman MI, USA) and expressed in pg/ml. Results were analyzed by the Kruskall Wallis test. Significant differences between the three cohorts were found, (H = 20.36, P < 0.001). Dunn´s multiple comparison analysis was performed, which showed significant differences between Groups 1 and 2, and between Groups 1 and 3 (P < 0.05). Higher values of IL-1β were found in the patients with histiocytosis with oral manifestations (Group 1) than in patients without manifestations (Group 2) and patients in the Control Group (Group 3).

  3. Rare case of unifocal Langerhans cell histiocytosis in four-month-old child.

    Science.gov (United States)

    Martins, Marco Antonio T; Gheno, José Luis N; Sant'Ana Filho, Manoel; Pinto, Décio S; Tenis, Carlos Alberto; Martins, Manoela D

    2011-07-01

    Langerhans cell histiocytosis (LCH) comprises a group of disorders, the common feature of which is Langerhans cell proliferation. The clinical presentation is highly varied. The severity and prognosis of the disease are dependent on the type and extent of organ involvement. This paper reports a rare case of a four-month-old white male with unifocal LCH limited exclusively to the mandible, discussing the diagnosis, radiographic and immunohistochemical aspects, treatment and monitoring multidisciplinary of the case. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  4. p53 expression in biopsies from children with Langerhans cell histiocytosis

    DEFF Research Database (Denmark)

    Bank, Micha I; Lundegaard, Pia Rengtved; Carstensen, Henrik

    2002-01-01

    PURPOSE: Langerhans cell histiocytosis (LCH) is a rare pediatric and adult disease causing skin rashes, osteolytic bone lesions, tumorous growth in various organs, and in some patients, organ dysfunction. The cause of the disease is obscure, and it is not yet understood why some patients develop...... in biopsies from children with LCH and correlate it with clinical manifestation and outcome in a broad range of organs. PATIENTS AND METHODS: The study was performed on 50 specimens from 32 children (19 boys and 13 girls), median age 3 1/4 years, range 5 months to 12 1/3 years with a definite diagnosis of LCH...

  5. BRAF V600E-Positive Multisite Langerhans Cell Histiocytosis in a Preterm Neonate

    Directory of Open Access Journals (Sweden)

    Sara V. Bates

    2013-10-01

    Full Text Available Hemorrhagic pustules with a “blueberry muffin” appearance accompanied by respiratory failure in a neonate present a challenging differential diagnosis that includes infections and neoplasms. We present a case of multiorgan, multisite Langerhans cell histiocytosis (LCH, positive for the oncogenic BRAF V600E mutation, in a preterm neonate. Infants with LCH pose a diagnostic challenge due to their heterogeneous presentations. This case is unusual in that the newborn presented with severe multiorgan involvement. Due to the rare incidence, wide spectrum of clinical manifestations, and high mortality rate, clinicians must maintain a high index of suspicion for LCH.

  6. Biliary dilatation secondary to lithiasis in a child affected by Langerhans' cell histiocytosis.

    Science.gov (United States)

    Caruso, Settimo; Miraglia, Roberto; Spada, Marco; Luca, Angelo; Gridelli, Bruno

    2009-01-01

    Langerhans' cell histiocytosis (LCH) is a disease of unknown pathogenesis, caused by clonal proliferation of Langerhans' cells. Liver involvement results in a cholangiopathy, which has the radiologic appearance of sclerosing cholangitis. Only 1 case of obstructive jaundice due to common bile duct stone in a patient with LCH has been described. We present a case of a 31-month-old child with LCH and liver involvement on the waiting list for liver transplantation. During the follow-up, there was a rapid onset of jaundice due to sludge and lithiasis. The patient was treated first with an endoscopic biliary plastic stent and then with percutaneous biliary drainage and bilioenteric anastomosis.

  7. Langerhans` cell histiocytosis of the spine: use of MRI in guiding biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, G.R.; Saifuddin, A. [Department of Diagnostic Imaging, Royal National Orthopaedic Hospital Trust, Brockley Hill (United Kingdom); Pringle, J.A.S. [Department of Morbid Anatomy, Royal National Orthopaedic Hospital Trust, Brockley Hill (United Kingdom); Noordeen, M.H.; Mehta, M.H. [Department of Spinal Deformities, Royal National Orthopaedic Hospital Trust, Brockley Hill (United Kingdom)

    1998-12-01

    The MRI features of two cases of spinal Langerhans` cell histiocytosis with multilevel involvement are presented in which MRI was of help in differentiating active from inactive healing lesions by the demonstration of signal changes in the vertebral body marrow of the active lesion, manifest as low signal intensity on T1-weighted sequences and high signal intensity on T2-weighted sequences. This distinction could not be made by plain radiography or bone scintigraphy. In cases where biopsy is required for diagnosis, MRI is recommended to guide the biopsy towards levels suggestive of active involvement. (orig.) With 7 figs., 13 refs.

  8. Ultrastructural observation of Charcot-Leyden crystals in mechlorethamine-treated cutaneous lesions of histiocytosis X.

    Science.gov (United States)

    Kanitakis, J; Schmitt, D; Euvrard, S; Thivolet, J

    1986-03-01

    We were recently able to observe, by electron microscopy, Charcot-Leyden crystals in the cutaneous lesions of histiocytosis X (Letterer-Siwe disease) that had been treated by local applications of mechlorethamine. The occurrence of Charcot-Leyden crystals in skin lesions is infrequent; so far, these structures have been observed only in cases of facial (Lever's) eosinophilic granuloma and in incontinentia pigmenti. Although Charcot-Leyden crystals can at times be formed spontaneously in tissue lesions, the possibility that their formation was favored by the local action of mechlorethamine is considered.

  9. A rare case of Langerhans cell histiocytosis of the skull in an adult: a systematic review

    Directory of Open Access Journals (Sweden)

    Corinna Chiong

    2013-07-01

    Full Text Available We report a 41-year old male who presented to the Emergency Department after falling while water-skiing. He had a previous medical history included chronic headaches, which had persisted for the last 2-3 months prior to presentation. Computed tomography of the head showed a small hypersensitivity with a small extra axial collection with a maximum thickness of 1 mm. Differential diagnoses included an arachnoid cyst, haemangioma, meningioma or a secondary lesion. A diagnosis of Langerhans Cell Histiocytosis was made based on the histopathology examination and the immunoperoxidase staining.

  10. The Role of Fascin in the Migration and Invasiveness of Malignant Glioma Cells

    Directory of Open Access Journals (Sweden)

    Jeong Hyun Hwang

    2008-02-01

    Full Text Available Malignant glioma is the most common primary brain tumor, and its ability to invade the surrounding brain parenchyma is a leading cause of tumor recurrence and treatment failure. Whereas the molecular mechanisms of glioma invasion are incompletely understood, there is growing evidence that cytoskeletal-matrix interactions contribute to this process. Fascin, an actin-bundling protein, induces parallel actin bundles in cell protrusions and increases cell motility in multiple human malignancies. The role of fascin in glioma invasion remains unclear. We demonstrate that fascin is expressed in a panel of human malignant glioma cell lines, and downregulation of fascin expression in glioma cell lines by small interfering RNA (siRNA is associated with decreased cellular attachment to extracellular matrix (ECM and reduced migration. Using immunofluorescence analysis, we show that fascin depletion results in a reduced number of filopodia as well as altered glioma cell shape. In vitro invasiveness of U251, U87, and SNB19 glioma cells was inhibited by fascin siRNA treatment by 52.2%, 40.3%, and 23.8% respectively. Finally, we show a decreased invasiveness of U251-GFP cells by fascin knockdown in an ex vivo rat brain slice model system. This is the first study to demonstrate a role for fascin in glioma cell morphology, motility, and invasiveness.

  11. VLBI: A Fascinating Technique for Geodesy and Astrometry

    Science.gov (United States)

    Schuh, H.; Behrend, Dirk

    2012-01-01

    Since the 1970s Very Long Baseline Interferometry (VLBI) has proven to be a primary space-geodetic technique by determining precise coordinates on the Earth, by monitoring the variable Earth rotation and orientation with highest precision, and by deriving many other parameters of the Earth system. VLBI provides an important linkage to astronomy through, for instance, the determination of very precise coordinates of extragalactic radio sources. Additionally, it contributes to determining parameters of relativistic and cosmological models. After a short review of the history of geodetic VLBI and a summary of recent results, this paper describes future perspectives of this fascinating technique. The International VLBI Service for Geodesy and Astrometry (IVS), as a service of the International Association of Geodesy (IAG) and the International Astronomical Union (IAU), is well on its way to fully defining a next generation VLBI system, called VLBI2010. The goals of the new system are to achieve on scales up to the size of the Earth an accuracy of 1 mm in position and of 0.1 mm/year in velocity. Continuous observations shall be carried out 24 h per day 7 days per week in the future with initial results to be delivered within 24 h after taking the data. Special sessions, e.g. for monitoring the Earth rotation parameters, will provide the results in near real-time. These goals require a completely new technical and conceptual design of VLBI measurements. Based on extensive simulation studies, strategies have been developed by the IVS to significantly improve its product accuracy through the use of a network of small (approx 12 m) fast-slewing antennas. A new method for generating high precision delay measurements as well as improved methods for handling biases related to radio source structure, system electronics, and deformations of the antenna structures has been developed. Furthermore, as of January 2012, the construction of ten new VLBI2010 sites has been funded, with

  12. Niemann-Pick disease, type B with TRAP-positive storage cells and secondary sea blue histiocytosis

    Directory of Open Access Journals (Sweden)

    R. Saxena

    2009-09-01

    Full Text Available We present 2 cases of Niemann Pick disease, type B with secondary sea-blue histiocytosis. Strikingly, in both cases the Pick cells were positive for tartrate resistant acid phosphatase, a finding hitherto described only in Gaucher cells. This report highlights the importance of this finding as a potential cytochemical diagnostic pitfall in the diagnosis of Niemann Pick disease.

  13. Hepatic involvement of Langerhans cell histiocytosis in children - imaging findings of computed tomography, magnetic resonance imaging and magnetic resonance cholangiopancreatography

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yingyan; Qiao, Zhongwei; Gong, Ying; Yang, Haowei; Li, Guoping; Pa, Mier [Children' s Hospital of Fudan University, Department of Radiology, Shanghai (China); Xia, Chunmei [Shanghai Medical College of Fudan University, Physiology and Pathophysiology Department, Shanghai (China)

    2014-06-15

    Langerhans cell histiocytosis is a rare disease that occurs mainly in children, and hepatic involvement is generally a poor prognostic factor. To describe CT and MRI findings of hepatic involvement of Langerhans cell histiocytosis in children, especially the abnormal bile duct manifestation on magnetic resonance cholangiopancreatography (MRCP). Thirteen children (seven boys, six girls; mean age 28.9 months) were diagnosed with disseminated Langerhans cell histiocytosis. They underwent CT (n = 5) or MRI (n = 4), or CT and MRI examinations (n = 4) to evaluate the liver involvement. Periportal abnormalities presented as band-like or nodular lesions on CT and MRI in all 13 children. The hepatic parenchymal lesions were found in the peripheral regions of the liver in seven children, including multiple nodules on MRI (n = 6), and cystic-like lesions on CT and MRI (n = 3). In 11 of the 13 children the dilatations of the bile ducts were observed on CT and MRI. Eight of the 13 children underwent MR cholangiopancreatography, which demonstrated stenoses or segmental stenoses with slight dilatation of the central bile ducts, including the common hepatic duct and its first-order branches. The peripheral bile ducts in these children showed segmental dilatations and stenoses. Stenosis of the central bile ducts revealed by MR cholangiopancreatography was the most significant finding of liver involvement in Langerhans cell histiocytosis in children. (orig.)

  14. Multisystem Langerhans cell histiocytosis coexisting with metastasizing adenocarcinoma of the lung: A case report

    Directory of Open Access Journals (Sweden)

    Lovrenski Aleksandra

    2013-01-01

    Full Text Available Introduction. Langerhans cell histiocytosis (LCH is an uncommon disease of unknown etiology characterized by uncontrolled proliferation and infiltration of various organs by Langerhans cells. Case report. We presented a 54-year-old man, heavy smoker, with dyspnea, cough, hemoptysis, headache and ataxia, who died shortly after admission to our hospital. On the autopsy, tumor was found in the posterior segment of the right upper pulmonary lobe as well as a right-sided occipitoparietal lesion which penetrated into the right ventricle resulting in internal and external hematocephalus. Histologically and immunohistohemically, the diagnosis of primary lung adenocarcinoma with brain metastasis was made (tumor cells showed positivity for CK7 and TTF-1 which confirmed the diagnosis. In the lung parenchyma around the tumor, as well as in brain tissue around the metastatic adenocarcinoma histiocytic lesions were found. Light microscopic examination of the other organs also showed histiocytic lesions involving the pituitary gland, hypothalamus, spleen and mediastinal lymph nodes. Immunohistochemical studies revealed CD68, S-100 and CD1a immunoreactivity within the histiocytes upon which the diagnosis of Langerhans' cells histiocytosis was made. Conclusion. The multisystem form of LCH with extensive organ involvement was an incidental finding, while metastatic lung adenocarcinoma to the brain that led to hematocephalus was the cause of death.

  15. Clinicopathological significance of fascin-1 expression in patients with non-small cell lung cancer

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    Ling XL

    2015-06-01

    Full Text Available Xiao-Ling Ling,* Tao Zhang,* Xiao-Ming Hou, Da Zhao Department of Oncology, The First Hospital of Lanzhou University (The Branch Hospital of Donggang, Lanzhou, Gansu Province, People’s Republic of China *These authors contributed equally to this work Purpose: Fascin-1 promotes the formation of filopodia, lamellipodia, and microspikes of cell membrane after its cross-linking with F-actin, thereby enhancing the cell movement and metastasis and invasion of tumor cells. This study explored the fascin-1 protein’s expression in non-small cell lung cancer (NSCLC tissues and its relationship with clinical pathology and prognostic indicators.Methods: Immunohistochemical analysis was used to determine the expression of fascin-1 in NSCLC tissues. We used quantitative real-time polymerase chain reaction and western blot analysis to further verify the results. The fascin-1 expression and statistical method for clinical pathological parameters are examined by χ2. Kaplan–Meier method is used for survival analysis. Cox’s Proportional Hazard Model was used to conduct a combined-effect analysis for each covariate.Results: In 73 of the 128 cases, NSCLC cancer tissues (57.0% were found with high expression of fascin-1, which was significantly higher than the adjacent tissues (35/128, 27.3%. The results suggested that the high expression of fascin-1 was significantly correlated with lymph node metastasis (P=0.022 and TNM stage (P=0.042. The high fascin-1 expression patients survived shorter than those NSCLC patients with low fascin-1 expression (P<0.05. Univariate analysis revealed that lymph node metastasis, TNM stage, and fascin-1 expression status were correlated with the overall survival. Similarly, lymph node metastasis, TNM stage, and fascin-1 expression status were significantly associated with the overall survival in multivariate analyses by using the Cox regression model.Conclusion: The fascin-1 protein may be a useful prognostic indicator and

  16. Isolated thymic Langerhans cell histiocytosis discovered on F-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT)

    Energy Technology Data Exchange (ETDEWEB)

    Turpin, Sophie [CHU Sainte-Justine, Nuclear Medicine, Montreal (Canada); Carret, Anne-Sophie [CHU Sainte-Justine, Hemato-Oncology, Montreal (Canada); Dubois, Josee [CHU Sainte-Justine, Radiology, Montreal (Canada); Buteau, Chantal [CHU Sainte-Justine, Infectious Diseases, Montreal (Canada); Patey, Natalie [CHU Sainte-Justine, Pathology, Montreal (Canada)

    2015-11-15

    The thymic infiltration in young patients with multisystemic Langerhans cell histiocytosis and its radiologic features are well known. However, isolated thymic disease has seldom been reported in the literature. We report the case of a 10-month-old child admitted for fever of unknown origin. Whole-body F-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) was performed to identify a focus of infection. It demonstrated an unusual aspect of the thymus, which led to further investigation and revealed isolated infiltration of the thymus by Langerhans cell histiocytosis. The patient was treated accordingly and is now disease free. As evaluation of Langerhans cell histiocytosis patients with F-18 FDG PET/CT is becoming more frequent, it is important to be aware of the scintigraphical characteristics of thymic Langerhans cell histiocytosis. (orig.)

  17. Clinicopathological significance of fascin and CD44v6 expression in endometrioid carcinoma

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    Gun Banu

    2012-07-01

    Full Text Available Abstract Background Fascin and CD44v6 may have significant roles as biomarkers in tumour progression and metastasis. In endometrioid carcinomas, the fascin expression profile is less defined, and the significance of CD44v6 is uncertain. We aimed to investigate the expressions of both fascin and CD44v6 in endometrioid carcinomas and to evaluate their inter-relation with clinicopathological parameters. Methods Fascin and CD44v6 expressions were evaluated, individually and in combination, in a series of 47 endometrioid carcinomas and 10 proliferative endometrium samples. The staining extent and intensity of both markers in tumour cells were scored semiquantitatively. The relationship between immunoexpressions and clinicopathological variables was assessed. Results The expression rates of fascin and CD44v6 in endometrioid carcinoma were 72.34% and 46.80%, respectively. Although these expression rates were higher than those in proliferative endometrial samples, fascin expression showed a statistically significant difference from the normal group (p = 0.02, but CD44v6 did not differ (p = 0.54. Fascin expression was significantly correlated with tumour grade (p = 0.003 and neural invasion (p = 0.036 in a univariate analysis. In contrast, no significant correlation was found between CD44v6 and any of the clinicopathological parameters. Conclusions Our findings suggest that fascin might be an independent prognostic indicator in the different steps of extracellular matrix invasion. On the other hand, CD44v6 was not a predictive factor in endometrioid cancer. Virtual Slides The virtual slide(s for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/8511594927206899.

  18. [Indeterminate cell histiocytosis - disappearance of skin infiltration following electron beam therapy and an application of 2-chlorodeoxyadenosine: case report].

    Science.gov (United States)

    Adam, Zdeněk; Ježová, Marta; Šlampa, Pavel; Křen, Leoš; Vašků, Vladimír; Koukalová, Renata; Řehák, Zdeněk; Pour, Luděk; Krejčí, Marta; Král, Zdeněk; Mayer, Jiří

    Indeterminate cell histiocytosis is a rare disease belonging to the group of malignant histiocytic diseases. The disease predominantly affects the skin. The disease appeared in the described patient at the age of 80 years. Morphs began to develop on the skin and rapidly spread over the whole body including the face. Only the hands and feet were left uncovered. The patients skin samples were taken from 2 sites for histological examination. The resulting conclusion was indeterminate cell histiocytosis. The treatment we chose was analogous to the procedures for Langerhans cell histiocytosis. We chose PUVA phototherapy as the first-line treatment. This treatment is frequently efficient for skin forms of Langerhans cell histiocytosis. In the described case, however, PUVA phototherapy did not influence the disease activity at all. As the second-line treatment, we used low-energy electron beam irradiation in the total dose of 36.2 Gy. This treatment had a positive impact, morphs began to diminish and slowly disappear from the skin. But they have not disappeared completely, therefore we assessed the treatment effect of the radiotherapy itself as partial remission of the disease. Within the third-line treatment, we used 2-chlorodeoxyadenosine in a dose of 5 mg/m2/per day, administered via subcutaneous injection over 5 consecutive days in monthly intervals. There were three cycles of this treatment administered overall. The treatment with 2-chlorodeoxyadenosine was tolerated without any adverse effects. The patient aged 82 years was only administered 3 cycles of 2-chlorodeoxyadenosine. When after the 3rd cycle the skin was free from any pathological morphs and only some pigmentation spots remained, we finished the treatment. The skin expressions of indeterminate cell histiocytosis completely disappeared after electron beam irradiation and the following administration of 3 cycles of 2-chlorodeoxyadenosine. The remission was short, however, after 6 months the disease recurred

  19. [Neuroimaging of Langerhans cell histiocytosis in the central nervous system of children].

    Science.gov (United States)

    De La Hoz Polo, M; Rebollo Polo, M; Fons Estupiña, C; Muchart López, J; Cruz Martinez, O

    2015-01-01

    Langerhans cell histiocytosis (LCH) is a rare disease characterized by the accumulation within tissues of anomalous dendritic cells similar to Langerhans cells. The clinical presentation varies, ranging from the appearance of a single bone lesion to multisystemic involvement. Central nervous system (CNS) involvement, manifesting as diabetes insipidus secondary to pituitary involvement, has been known since the original description of the disease. Two types of CNS lesions are currently differentiated. The first, pseudotumoral lesions with infiltration by Langerhans cells, most commonly manifests as pituitary infiltration. The second, described more recently, consists of neurodegenerative lesions of the CNS associated with neurologic deterioration. This second type of lesion constitutes a complication of the disease; however, there is no consensus about the cause of this complication. Our objective was to describe the radiologic manifestations of LCH in the CNS in pediatric patients. Copyright © 2013 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  20. Langerhans cell histiocytosis: A case report of a three year old boy with primary oral manifestations

    Directory of Open Access Journals (Sweden)

    Seraj B

    2006-06-01

    Full Text Available Langerhans cell histiocytosis (LCH is a rare disease with formation of granulomatous infiltrations consisting of Langerhans cells, histiocytes, lymphocytes and eosinophilic granulocytes. The ethiopathogenesis of the disease has not been fully clarified yet. It can occur as focal or disseminated form - acute or chronic. Oral manifestations may be the first signs. This article reports a case of a 3 year old boy with LCH suffering from severe dental mobility and foul breathe. Radiographically, the lesions appeared as well-defined radiolucent defects in maxilla and mandible. The microscopic findings consisted of sheet like arrangements of histiocytes with a mixture of eosinophils and other inflammatory cells. Biochemical tests were within normal limits.

  1. Polyclonal T-cells express CD1a in Langerhans cell histiocytosis (LCH lesions.

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    Jennifer A West

    Full Text Available Langerhans cell histiocytosis (LCH is a complex and poorly understood disorder that has characteristics of both inflammatory and neoplastic disease. By using eight-colour flow cytometry, we have identified a previously unreported population of CD1a(+/CD3(+ T-cells in LCH lesions. The expression of CD1a is regarded as a hallmark of this disease; however, it has always been presumed that it was only expressed by pathogenic Langerhans cells (LCs. We have now detected CD1a expression by a range of T-cell subsets within all of the LCH lesions that were examined, establishing that CD1a expression in these lesions is no longer restricted to pathogenic LCs. The presence of CD1a(+ T-cells in all of the LCH lesions that we have studied to date warrants further investigation into their biological function to determine whether these cells are important in the pathogenesis of LCH.

  2. A Rare Case of Erdheim-Chester Disease and Langerhans Cell Histiocytosis Overlap Syndrome

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    Shahzaib Nabi

    2015-01-01

    Full Text Available A 48-year-old woman with a past medical history of seizures and end-stage renal disease secondary to obstructive uropathy from retroperitoneal fibrosis presented to the emergency department with seizures and altered mental status. A Glasgow Coma Scale of 4 prompted intubation, and she was subsequently admitted to the intensive care unit. Magnetic resonance imaging of the brain performed to elucidate the aetiology of her seizure showed a dural-based mass within the left temporoparietal lobe as well as mass lesions within the orbits. Further imaging showed extensive retroperitoneal fibrosis extending to the mediastinum with involvement of aorta and posterior pleural space. Imaging of the long bones showed bilateral sclerosis and cortical thickening of the diaphyses. Imaging of the maxillofacial structures showed osseous destructive lesions involving the mandible. These clinical and radiological features were consistent with a diagnosis of Erdheim-Chester disease; however, the patient’s skin biopsy was consistent with Langerhans cell histiocytosis.

  3. Pulmonary Langerhans cell histiocytosis in children: A spectrum of radiologic findings

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    Bano, Shahina, E-mail: dr_shahinaindia@yahoo.com [Department of Radiodiagnosis, Lady Hardinge Medical College and Associated Hospitals, New Delhi 110001 (India); Chaudhary, Vikas, E-mail: dr_vikaschaudhary@yahoo.com [Department of Radiodiagnosis, Employees’ State Insurance Corporation (ESIC) Model Hospital, Gurgaon 122001, Haryana (India); Narula, Mahender Kaur, E-mail: narulamk@gmail.com [Department of Radiodiagnosis, Lady Hardinge Medical College and Associated Hospitals, New Delhi 110001 (India); Anand, Rama, E-mail: rama_home@yahoo.co.in [Department of Radiodiagnosis, Lady Hardinge Medical College and Associated Hospitals, New Delhi 110001 (India); Venkatesan, Bhuvaneswari, E-mail: venkatesanbhuvana@yahoo.com [Department of Radiodiagnosis, Lady Hardinge Medical College and Associated Hospitals, New Delhi 110001 (India); Mandal, Shramana, E-mail: shramana@hotmail.co.in [Department of Pathology, Govind Ballabh Pant Hospital, New Delhi 110002 (India); Majumdar, Kaushik, E-mail: drkaushik.m@gmail.com [Department of Pathology, Govind Ballabh Pant Hospital, New Delhi 110002 (India)

    2014-01-15

    Pulmonary Langerhans cell histiocytosis (PLCH) is a well known entity in adults but is exceedingly rare in children. It is better described in adults than in children. We describe the current understanding of PLCH in children and a spectrum of radiological findings of PLCH in the paediatric population. On high resolution computed tomography (HRCT), PLCH may have variable appearance depending on the stage of disease, ranging from small interstitial nodular opacities to multiple thin/thick walled cysts (often bizarre in shape), eventually leading to marked parenchymal fibrosis and honeycomb pattern. CT finding of PLCH is similar in adult and paediatric populations with the exception that lung base near the costophrenic angle is spared in adults but almost always involved in children.

  4. Pulmonary Langerhans Cell Histiocytosis and Diabetes Insipidus in a Young Smoker

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    K. Earlam

    2016-01-01

    Full Text Available Langerhans cell histiocytosis is characterized by the abnormal nodular proliferation of histiocytes in various organ systems. Pulmonary involvement seen in young adults is nearly always seen in the context of past or current cigarette smoking. Although it tends to be a single-system disease, extrapulmonary manifestations involving the skin, bone, and hypothalamic-pituitary-axis are possible. High resolution CT (HRCT of the thorax findings includes centrilobular nodules and cysts that are bizarre in shape, variable in size, and thin-walled. Often the diagnosis can be made based on the appropriate clinical presentation and typical imaging findings. Treatment includes smoking cessation and the potential use of glucocorticoids or cytotoxic agents depending on the severity of disease and multisystem involvement.

  5. Results of Treatment with 2-Chlorodeoxyadenosine (2-CDA in Multiple Reactivations or Refractory Langerhans Cell Histiocytosis

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    Ghasem Miri-Aliabad

    2014-01-01

    Full Text Available Background: Langerhans cell histiocytosis (LCH is the most common type of histiocytosis and characterized by abnormal proliferation and excess accumulation of inflammatory and langerhans cells at various tissue sites. Clinical manifestations are variable, ranging from spontaneously regressing single bone lesion to multisystem disease, life-threatening and refractory to treatment. Conventional chemotherapy has been shown to be effective in treatment of majority of patients with LCH. However, treatment of refractory disease or multiple reactivations is difficult. The aim of this study is to assess the efficacy of 2-CDA in relapsed or refractory LCH. Materials and methods: Four patients with relapsed or refractory LCH that were treated with 2-chlorodeoxyadenosin (2-CDA enrolled in this study. All patients had received at least one prior chemotherapy regimen. The dose and schedule of 2-CDA was 6 mg/m²/day for 5 days every 3-4 weeks. Results: Median age at the time of treatment with 2-CDA was 9.7 years. Three patients had multisystem disease and one had multifocal bone lesions. All patients had multifocal bone lesions. None of them had risk organ involvement. Mean course of treatment with 2-CDA was 9.5. Radiologic evaluations revealed complete resolution of bone lesions in two (50% patients. In one (25% patient lesions regressed (partial response and in another (25% the disease remained stable. Drug related side effects were minimal. At the present time all patients are alive. Conclusion: Our study demonstrates that 2-CDA as a single agent is efficacious in treatment of multiple reactivations or refractory LCH and well-tolerated in children.

  6. Combined proximal tubulopathy, crystal-storing histiocytosis, and cast nephropathy in a patient with light chain multiple myeloma.

    Science.gov (United States)

    Wu, Chung-Kuan; Yang, An-Hang; Lai, Hung-Chih; Lin, Bing-Shi

    2017-05-25

    The diagnosis of myeloma, a plasma dyscrasia, often results from the workup of unexplained renal disease. Persistent renal failure in myeloma is commonly caused by tubular nephropathy due to circulating immunoglobulins and free light chains. Myeloma cast nephropathy is characterized by crystalline precipitates of monoclonal light chains within distal tubules. Immunoglobulin crystallization rarely occurs intracellularly, within proximal tubular cells (light chain proximal tubulopathy) and interstitial histiocytes (crystal-storing histiocytosis). We present a case report of a rare simultaneous occurrence of light chain proximal tubulopathy, crystal-storing histiocytosis, and myeloma cast nephropathy in a patient with κ light chain multiple myeloma. A 48-years-old man presented with uremia and anemia. Laboratory examination revealed low levels of serum IgG, IgA, and IgM. Serum and urine immunofixation electrophoresis showed a free κ monoclonal band. Bone marrow aspiration and biopsy revealed hypercellularity with marked plasmacytosis. Light microscopy revealed eosinophilic cuboid- and rhomboid-shaped crystals in the cytoplasm of proximal tubular epithelial cells, diffuse large mononuclear and multinuclear cells in the interstitium, and obstructed distal tubules with cast and giant cell reaction. Immunohistochemical examination indicated intense staining for κ light chains within casts, histiocytes, and tubular epithelial cells. Electron microscopy revealed electro-dense cuboid-, rhomboid-, or needle-shaped crystalline inclusions in proximal tubular epithelial cells and interstitial histiocytes. According to these results, we confirmed that this patient with myeloma exhibited simultaneous light chain proximal tubulopathy, crystal-storing histiocytosis, and myeloma cast nephropathy, which were attributed to monoclonal κ light chains. In addition to dialysis, the patient received induction chemotherapy with a combination of bortezomib, cyclophosphamide, and

  7. Primary Langerhans cell histiocytosis (LCH in the adult cervical spine: A case report and review of the literature

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    Sang-Deok Kim, M.D.

    2017-03-01

    Full Text Available Langerhans cell histiocytosis (LCH of the spine is a common benign disease in children and adolescents that rarely affects adults. Main management of single lesion (unifocal vertebral LCH is conservative method, unless there is neurological deficit due to mass effect, surgery must be considered. This is an interesting and rare case report of the patient with LCH at C5 vertebral body who underwent fusion surgery.

  8. Pulmonary Langerhans Cell Histiocytosis in an Adult Male Presenting with Central Diabetes Insipidus and Diabetes Mellitus: A Case Report.

    Science.gov (United States)

    Choi, Yeun Seoung; Lim, Jung Soo; Kwon, Woocheol; Jung, Soon-Hee; Park, Il Hwan; Lee, Myoung Kyu; Lee, Won Yeon; Yong, Suk Joong; Lee, Seok Jeong; Jung, Ye-Ryung; Choi, Jiwon; Choi, Ji Sun; Jeong, Joon Taek; Yoo, Jin Sae; Kim, Sang-Ha

    2015-10-01

    Pulmonary Langerhans cell histiocytosis is an uncommon diffuse cystic lung disease in adults. In rare cases, it can involve extrapulmonary organs and lead to endocrine abnormalities such as central diabetes insipidus. A 42-year-old man presented with polyphagia and polydipsia, as well as a dry cough and dyspnea on exertion. Magnetic resonance imaging of the hypothalamic-pituitary system failed to show the posterior pituitary, which is a typical finding in patients with central diabetes insipidus. This condition was confirmed by a water deprivation test, and the patient was also found to have type 2 diabetes mellitus. Computed tomographic scanning of the lungs revealed multiple, irregularly shaped cystic lesions and small nodules bilaterally, with sparing of the costophrenic angles. Lung biopsy through video-assisted thoracoscopic surgery revealed pulmonary Langerhans cell histiocytosis. On a follow-up visit, only 1 year after the patient had quit smoking, clinical and radiological improvement was significant. Here, we report an uncommon case of pulmonary Langerhans cell histiocytosis that simultaneously presented with diabetes insipidus and diabetes mellitus.

  9. Pulmonary Langerhans Cell Histiocytosis in an Adult Male Presenting with Central Diabetes Insipidus and Diabetes Mellitus: A Case Report

    Science.gov (United States)

    Choi, Yeun Seoung; Lim, Jung Soo; Kwon, Woocheol; Jung, Soon-Hee; Park, Il Hwan; Lee, Myoung Kyu; Lee, Won Yeon; Yong, Suk Joong; Lee, Seok Jeong; Jung, Ye-Ryung; Choi, Jiwon; Choi, Ji Sun; Jeong, Joon Taek; Yoo, Jin Sae

    2015-01-01

    Pulmonary Langerhans cell histiocytosis is an uncommon diffuse cystic lung disease in adults. In rare cases, it can involve extrapulmonary organs and lead to endocrine abnormalities such as central diabetes insipidus. A 42-year-old man presented with polyphagia and polydipsia, as well as a dry cough and dyspnea on exertion. Magnetic resonance imaging of the hypothalamic-pituitary system failed to show the posterior pituitary, which is a typical finding in patients with central diabetes insipidus. This condition was confirmed by a water deprivation test, and the patient was also found to have type 2 diabetes mellitus. Computed tomographic scanning of the lungs revealed multiple, irregularly shaped cystic lesions and small nodules bilaterally, with sparing of the costophrenic angles. Lung biopsy through video-assisted thoracoscopic surgery revealed pulmonary Langerhans cell histiocytosis. On a follow-up visit, only 1 year after the patient had quit smoking, clinical and radiological improvement was significant. Here, we report an uncommon case of pulmonary Langerhans cell histiocytosis that simultaneously presented with diabetes insipidus and diabetes mellitus. PMID:26508947

  10. Langerhans Cell Histiocytosis in Childhood: Review, Symptoms in the Oral Cavity, Differential Diagnosis and Report of One Case

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    Mohammad Shooriabi

    2016-08-01

    Full Text Available Background Langerhans cell histiocytosis (LCH is a rare disease in which monoclonal migration and proliferation of specific dendritic cells is seen. The disease primarily affects the bones and skin, but there is a possibility that involves other organs or appears as a multi-systemic disease. Case Report In oral examination of a nine-month girl, two deep wounds with a yellow membrane with approximate size of 1 × 1 cm on both sides of mandibular alveolar ridge were seen. The edges of the wounds were swollen and proliferated and redder than the surrounding mucosa. At the touch the edges of the wound were not indurated. The wound were created from the third-month and the size of wounds had become slightly larger within 6 months. According to the chronic wound and being non-responsive to various systemic and local treatments, incisional biopsy was taken from the wounds. Langerhans cell histiocytosis was confirmedhistologically and immune histochemically. Conclusion Mouth ulcers may be the only symptoms of Langerhans cell histiocytosis. Therefore, the role of dentist could be important in diagnosis of this disease.

  11. Report on final demonstration. Fascinate deliverable D6.3.1

    OpenAIRE

    Thomas, Graham; Schreer, Oliver; Thallinger, Georg; Kienast, Gert; Oldfield, Rob; Ruiz Hidalgo, Javier; Macq, Jean François; Prins, M.J.

    2013-01-01

    The objective of WP6 in the FascinatE project is to organise a series of convincing demonstrations that raise awareness of the project in the broadcast and media industry, as well as providing focal points for the technical work of the project. This document reports on the third and final public demonstration of FascinatE technology, held at MediaCity UK, at the premises of the University of Salford. The centrepiece of the demonstration was the use of the end-to-end Fasci...

  12. Formens fascination

    DEFF Research Database (Denmark)

    Prebensen, Henrik

    2006-01-01

    Sprogvidenskab, matematisk lingvistik, matematik, humaniora, sprogform, Saussure, Frege, Russel, Reichenbach, Chomsky, formalisme, funktionalisme......Sprogvidenskab, matematisk lingvistik, matematik, humaniora, sprogform, Saussure, Frege, Russel, Reichenbach, Chomsky, formalisme, funktionalisme...

  13. Kubens fascination

    DEFF Research Database (Denmark)

    Skude, Flemming

    2002-01-01

    Anmeldelse af Nykredits domicil på Kalvebod Brygge referende til Ford Foundation i New York og nutidens præference for minimalistisk kubisme.......Anmeldelse af Nykredits domicil på Kalvebod Brygge referende til Ford Foundation i New York og nutidens præference for minimalistisk kubisme....

  14. Fluid Fascinations

    NARCIS (Netherlands)

    Bokhove, Onno; Zwart, Valerie; Haveman, Martha J.

    De Art & Science show “Fluid Fascinations��? omvat een presentatie over de wetenschappelijke context, inclusief een live experiment (ontworpen samen met kunstenaar/designer Wout Zweers); en, gemengde media en olieverfschilderijen, en digitale fotowerken van kunstenares Valerie Zwart. De show is

  15. A novel Rho-dependent pathway that drives interaction of fascin-1 with p-Lin-11/Isl-1/Mec-3 kinase (LIMK 1/2 to promote fascin-1/actin binding and filopodia stability

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    Jayo Asier

    2012-08-01

    Full Text Available Abstract Background Fascin-1 is an actin crosslinking protein that is important for the assembly of cell protrusions in neurons, skeletal and smooth muscle, fibroblasts, and dendritic cells. Although absent from most normal adult epithelia, fascin-1 is upregulated in many human carcinomas, and is associated with poor prognosis because of its promotion of carcinoma cell migration, invasion, and metastasis. Rac and Cdc42 small guanine triphosphatases have been identified as upstream regulators of the association of fascin-1 with actin, but the possible role of Rho has remained obscure. Additionally, experiments have been hampered by the inability to measure the fascin-1/actin interaction directly in intact cells. We investigated the hypothesis that fascin-1 is a functional target of Rho in normal and carcinoma cells, using experimental approaches that included a novel fluorescence resonance energy transfer (FRET/fluorescence lifetime imaging (FLIM method to measure the interaction of fascin-1 with actin. Results Rho activity modulates the interaction of fascin-1 with actin, as detected by a novel FRET method, in skeletal myoblasts and human colon carcinoma cells. Mechanistically, Rho regulation depends on Rho kinase activity, is independent of the status of myosin II activity, and is not mediated by promotion of the fascin/PKC complex. The p-Lin-11/Isl-1/Mec-3 kinases (LIMK, LIMK1 and LIMK2, act downstream of Rho kinases as novel binding partners of fascin-1, and this complex regulates the stability of filopodia. Conclusions We have identified a novel activity of Rho in promoting a complex between fascin-1 and LIMK1/2 that modulates the interaction of fascin-1 with actin. These data provide new mechanistic insight into the intracellular coordination of contractile and protrusive actin-based structures. During the course of the study, we developed a novel FRET method for analysis of the fascin-1/actin interaction, with potential general

  16. Insights into the pathogenesis of Langerhans cell histiocytosis: the development of targeted therapies

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    Hutter C

    2016-10-01

    Full Text Available Caroline Hutter,1,2 Milen Minkov1–3 1International LCH Study Reference Center, Children’s Cancer Research Institute, Vienna, Austria; 2St. Anna Children's Hospital, University Clinic of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria; 3Department of Pediatrics, Adolescent Medicine and Neonatology, Rudolfstiftung Hospital, Vienna, Austria Abstract: More than a century after its first description, Langerhans cell histiocytosis (LCH still remains an intriguing disease. Considerable progress in understanding its biology has been achieved recently. Description of the V600E BRAF mutation in samples of LCH tissue in 2010 was followed by description of additional mutations, all leading to constitutive ERK activation. Current experimental data suggest that LCH is a myeloid neoplasia with inflammatory properties, yet the exact pathophysiology remains poorly understood. Disease management paradigms have changed over time, closely reflecting the evolving view of the nature of the disease. The international Histiocyte Society have conducted three prospective clinical studies on multisystem LCH since the early 1990s. The standard frontline therapy for patients with multisystem LCH based on the cumulative knowledge of those trials consists of 6–12 weeks of initial therapy (daily oral steroids and weekly vinblastine injections, followed by pulses of prednisolone/vinblastine every 3 weeks, for a total treatment duration of 12 months. A currently ongoing study (LCH-IV with a complex design (five interventional and two observational strata targets further reduction of mortality and morbidity by tailoring treatment intensity depending on expected risk, as well as by exploring treatment regimens for special locations. Current knowledge on LCH pathobiology opens opportunities for improvement in the patient outcome. The activating BRAF and MAP2K1 mutations collectively accounting for about 75% of the LCH population as well as

  17. Adult Multisystem Langerhans Cell Histiocytosis Presenting with Central Diabetes Insipidus Successfully Treated with Chemotherapy

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    Jung-Eun Choi

    2014-09-01

    Full Text Available We report the rare case of an adult who was diagnosed with recurrent multisystem Langerhans cell histiocytosis (LCH involving the pituitary stalk and lung who present with central diabetes insipidus and was successfully treated with systemic steroids and chemotherapy. A 49-year-old man visited our hospital due to symptoms of polydipsia and polyuria that started 1 month prior. Two years prior to presentation, he underwent excision of right 6th and 7th rib lesions for the osteolytic lesion and chest pain, which were later confirmed to be LCH on pathology. After admission, the water deprivation test was done and the result indicated that he had central diabetes insipidus. Sella magnetic resonance imaging showed a mass on the pituitary stalk with loss of normal bright spot at the posterior lobe of the pituitary. Multiple patchy infiltrations were detected in both lung fields by computed tomography (CT. He was diagnosed with recurrent LCH and was subsequently treated with inhaled desmopressin, systemic steroids, vinblastine, and mercaptopurine. The pituitary mass disappeared after two months and both lungs were clear on chest CT after 11 months. Although clinical remission in multisystem LCH in adults is reportedly rare, our case of adult-onset multisystem LCH was treated successfully with systemic chemotherapy using prednisolone, vinblastine, and 6-mercaptopurine, which was well tolerated.

  18. Radiologic findings of adult pelvis and appendicular skeletal Langerhans cell histiocytosis in nine patients

    Energy Technology Data Exchange (ETDEWEB)

    Song, You Seon; Lee, In Sook; Kim, Do Kyung [Pusan National University Hospital, Medical Research Institute, Department of Radiology, Busan (Korea, Republic of); Pusan National University, School of Medicine, Department of Radiology, Busan (Korea, Republic of); Yi, Jae Hyuck [Kyungpook National University Hospital, Department of Radiology, Daegu (Korea, Republic of); Cho, Kil Ho [Yeungnam University College of Medicine, Department of Radiology, Daegu (Korea, Republic of); Song, Jong Woon [Inje University Haeundae Paik Hospital, Department of Radiology, Busan (Korea, Republic of)

    2011-11-15

    The purpose of this article was to evaluate the radiologic findings of adult pelvis and appendicular skeletal Langerhans cell histiocytosis (LCH), emphasizing the CT and MR findings. The images of nine patients with pathologically proven LCH (five men and four women; mean age, 37.11 years) were retrospectively reviewed. Imaging analysis was confined to the long and flat bones. CT scans were performed in five patients and MR imaging was performed in eight. Images were assessed for the following features on CT and MRI: the location and number of lesions; the presence of cortical destruction, endosteal scalloping, and a periosteal reaction on CT or MRI; the margin of soft tissue masses, the presence of bone marrow edema, and a ''budding'' appearance on MRI; and the presence of sclerotic margins or septations on CT. The involved skeletal sites were the pelvis (seven), femurs (five), humeri (two), tibias (two), fibula (one), clavicle (one), scapula (one), and sternum (one). Endosteal scalloping, a periosteal reaction, and a budding appearance were common on MRI or CT images. Although cortical destruction and the soft tissue lesion formation were rare, soft tissue masses had well-defined margins. Endosteal scalloping and a budding appearance with a periosteal reaction on CT and MRI may be helpful signs for differentiation of LCH from malignant tumors in adults. (orig.)

  19. Langerhans cell histiocytosis: literature review and descriptive analysis of oral manifestations.

    Science.gov (United States)

    Madrigal-Martínez-Pereda, Cristina; Guerrero-Rodríguez, Vanesa; Guisado-Moya, Blanca; Meniz-García, Cristina

    2009-05-01

    Langerhans cell histiocytosis (LCH) is a rare disease, of unknown pathogenesis, characterized by intense and abnormal proliferation of bone marrow-derived histiocytes (Langerhans cells). It can present both local and systemic manifestations involving bone, skin and mucosal tissue, and internal organs. Three basic clinical forms develop: Letterer-Siwe disease (subacute or acute disseminated form), Hand-Schüller-Christian disease (disseminated chronic form) and eosinophilic granuloma (localized chronic form). LCH may manifest orally with single or multiple lesions of the alveolar or basal bone, ulcerated mucosal lesions accompanied by adenopathies and/or periodontal lesions, presenting gingival inflammation, bleeding, recession, necrosis, odontalgia, dental hypermobility and premature loss of teeth. The principal differential diagnoses include advanced periodontal disease or a periapical process of dental or periodontal origin. The odontologist plays a vital role in the diagnosis and multidisciplinary treatment of such patients, by performing routine examinations for periodic follow-up of the disease and its possible oral manifestations, bearing in mind that these may be the first or only signs of LCH.

  20. {sup 18}F-FDG PET in neuro-degenerative Langerhans cell histiocytosis

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    Ribeiro, M.Jo. [CEA, DSV, DRM, Serv Hosp Frederic Joliot, F-91406 Orsay (France); Idbaih, A.; Hoang-Xuan, K. [UPMC, Grp Hosp Pitie Salpetriere, ServNeurol Mazarin, AP-HP, Paris (France); Thomas, C. [CHU Nantes, Unite Hematol et Oncol Pediat, F-44035 Nantes 01 (France); Remy, P. [CEA, Serv Hosp Frederic Joliot, CNRS, URA 2210, F-91406 Orsay (France); Remy, P. [CHU Henri Mondor, Fac Med Paris 12, Dept Neurosci, AP-HP, F-94010 Creteil (France)

    2008-07-01

    Introduction: The so called 'neuro-degenerative Langerhans cell histiocytosis' (ND-LCH) is a rare and severe complication of LCH presenting as a progressive cerebellar ataxia associated with pyramidal tract signs, and cognitive impairment. MRI is the gold standard to investigate CNS lesions of ND-LCH but little is known about functional changes observed in this disease. Objectives: To search for CNS metabolic changes in NDLCH. Methods: Seven patients suffering from ND-LCH were investigated by {sup 18}F-FDG PET in this prospective study and compared with 21 healthy controls. Results: ND-LCH patients demonstrated recurrent abnormalities including bilateral hypo-metabolism in the cerebellum, the basal ganglia (caudate nuclei), frontal cortex and, bilateral, a relatively increased metabolism in the amygdalae (p {<=} 0.001). Functional changes in these anatomical regions may be detected in the absence of any apparent lesion on MRI. Conclusions: ND-LCH demonstrates a recurrent {sup 18}F-FDG PET metabolic signature. Our results suggest that {sup 18}F-FDG PET might be a useful tool for an early diagnosis of ND-LCH before neuro-radiologic abnormalities appear. (authors)

  1. Efficacy of vinblastine in central nervous system Langerhans cell histiocytosis: a nationwide retrospective study

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    Ng Wing Tin Sophie

    2011-12-01

    Full Text Available Abstract Background Vinblastine (VBL is the standard treatment for systemic Langerhans cell histiocytosis (LCH, but little is known about its efficacy in central nervous system (CNS mass lesions. Methods A retrospective chart review was conducted. Twenty patients from the French LCH Study Group register met the inclusion criteria. In brief, they had CNS mass lesions, had been treated with VBL, and were evaluable for radiologic response. Results The median age at diagnosis of LCH was 11.5 years (range: 1-50. Intravenous VBL 6 mg/m2 was given in a 6-week induction treatment, followed by a maintenance treatment. The median total duration was 12 months (range: 3-30. Eleven patients received steroids concomitantly. Fifteen patients achieved an objective response; five had a complete response (CR: 25%, ten had a partial response (PR: 50%, four had stable disease (SD: 20% and one patient progressed (PD: 5%. Of interest, four out of the six patients who received VBL without concomitant steroids achieved an objective response. With a median follow-up of 6.8 years, the 5-year event-free and overall survival was 61% and 84%, respectively. VBL was well-tolerated and there were no patient withdrawals due to adverse events. Conclusion VBL, with or without steroids, could potentially be a useful therapeutic option in LCH with CNS mass lesions, especially for those with inoperable lesions or multiple lesions. Prospective clinical trials are warranted for the evaluation of VBL in this indication.

  2. Langerhans Cell Histiocytosis Mimicking Periapical Pathology in a 39-year-old Man.

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    Peters, Scott M; Pastagia, Julie; Yoon, Angela J; Philipone, Elizabeth M

    2017-11-01

    Langerhans cell histiocytosis (LCH) is a clonal neoplastic proliferation of Langerhans-type dendritic cells, with more than 50% of cases of LCH seen in children younger than 15 years of age. The most common clinical presentation of LCH is solitary or multiple bony lesions. The jaws are affected in approximately 10%-20% of cases, with a strong predilection for the mandible. The maxilla is involved in only 1% of head and neck cases. When the jaws are involved, lesions of LCH may mimic periapical pathology as seen in patients requiring endodontic therapy or bone loss as seen in periodontal disease. We report the case of a 39-year-old man with LCH involving the posterior maxilla. This is a rare presentation of LCH with respect to both location and patient age. Clinicians should consider LCH when developing a differential diagnosis of an apical radiolucency of vital teeth or teeth that fail to respond to endodontic therapy and be aware of its clinical and radiographic mimics. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  3. More than just Langerhans cell histiocytosis: a radiologic review of histiocytic disorders.

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    Zaveri, Jatin; La, Quan; Yarmish, Gail; Neuman, Jeremy

    2014-01-01

    Although Langerhans cell histiocytosis (LCH) is a familiar entity to most radiologists and to pediatric radiologists in particular, it is but one of a group of disorders caused by the overproduction of histiocytes, a subtype of white blood cells. Other less familiar diseases in this category are Erdheim-Chester disease (ECD), juvenile xanthogranuloma (JXG), Rosai-Dorfman disease (RDD), and hemophagocytic lymphohistiocytosis (HLH). This review describes the classification system, clinical manifestations, and pathophysiology of each disease, with particular attention to differential radiographic findings, including typical locations of involvement and varying appearances at radiography, computed tomography, magnetic resonance imaging, ultrasonography, and nuclear medicine imaging. Although LCH has a wide variety of manifestations and appearances, classic imaging findings include vertebra plana, skull lesions with a beveled edge, the "floating tooth" sign, bizarre lung cysts, and an absent posterior pituitary bright spot with infundibular thickening. The classic imaging findings of ECD are a perirenal rind of soft tissue and patchy long bone osteosclerosis. RDD has more nonspecific imaging findings, including lymphadenopathy (most commonly cervical) and intracranial lesions. Imaging findings in HLH are broad, with the most common abnormalities being hepatosplenomegaly, cerebral volume loss, and periventricular white matter abnormalities. JXG can manifest at imaging, but radiology does not play a major role in diagnosis. Familiarity with these disorders and their associated imaging findings facilitates correct and timely diagnosis. Imaging also features prominently in the assessment of treatment response. ©RSNA, 2014.

  4. Evaluation and treatment of Langerhans cell histiocytosis patients with central nervous system abnormalities: Current views and new vistas.

    Science.gov (United States)

    Yeh, E Ann; Greenberg, Jay; Abla, Oussama; Longoni, Giulia; Diamond, Eli; Hermiston, Michelle; Tran, Brandon; Rodriguez-Galindo, Carlos; Allen, Carl E; McClain, Kenneth L

    2018-01-01

    Central nervous system (CNS) involvement in Langerhans cell histiocytosis (LCH) can include mass lesions of the hypothalamic pituitary axis, choroid plexus, cerebrum, and cerebellum or magnetic resonance imaging (MRI) signal abnormalities of the cerebellum, pons, and basal ganglia. The term neurodegenerative (ND) CNS-LCH has been given to the MRI signal abnormalities and neurologic dysfunction, although initially patients may have no clinical symptoms. Standardized evaluations to better understand the natural history and response to therapy are needed. We propose guidelines for clinical, radiologic, and physiologic tests as a framework for developing the best methods of evaluation, which can then be tested in prospective treatment protocols. © 2017 Wiley Periodicals, Inc.

  5. Prognostic significance of fascin expression in advanced colorectal cancer: an immunohistochemical study of colorectal adenomas and adenocarcinomas

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    Mukherjee Abir L

    2006-10-01

    Full Text Available Abstract Background Fascin is an actin bundling protein with roles in the formation of cell protrusions and motility of mesenchymal and neuronal cells. Fascin is normally low or absent from epithelia, but is upregulated in several epithelial neoplasms where it may contribute to an invasive phenotype. Here, we report on the prevalence and potential clinical significance of fascin expression in relation to the progression of colorectal adenocarcinoma and to tumor cell proliferation as measured by Ki67 index. Methods Conventional tissue sections of 107 colorectal adenomas and 35 adenocarcinomas were analyzed by immunohistochemistry for fascin and Ki67 expression. Fascin expression and Ki67 proliferation index were also investigated by use of a tissue microarray containing cores from a further 158 colorectal adenocarcinomas and 15 adenomas linked to a CCF, IRB-approved database with a mean of 38 months of clinical follow-up. Survival analysis was carried out by the Kaplan-Meier and Cox regression methods. Results Fascin was not expressed by the normal colonic epithelium. In conventional sections, 16% of adenomas and 26% of adenocarcinomas showed fascin expression in greater than 10% of the tumor cells. In the clinically-annotated tumors, fascin immunoreactivity was more common in tumors located in the proximal colon (p = 0.009, but was not associated with age, gender, or TNM stage. Patients with stage III/IV adenocarcinomas (n = 62 with strong fascin immunoreactivity had a worse prognosis than patients with low or absent fascin, (3-year overall survival of 11% versus 43% for fascin-negative patients; p = 0.023. In adenomas, fascin and Ki67 tended to be inversely correlated at the cellular level; this trend was less apparent in adenocarcinomas. Conclusion Fascin is upregulated in a proportion of adenomas, where its expression is often focal. Strong and diffuse expression was seen in a subset of advanced colorectal adenocarcinomas that correlated with

  6. BRAF and MAP2K1 mutations in Langerhans cell histiocytosis: a study of 50 cases.

    Science.gov (United States)

    Alayed, Khaled; Medeiros, L Jeffrey; Patel, Keyur P; Zuo, Zhuang; Li, Shaoying; Verma, Shalini; Galbincea, John; Cason, R Craig; Luthra, Rajyalakshmi; Yin, C Cameron

    2016-06-01

    Langerhans cell histiocytosis (LCH) is a proliferation of Langerhans cells, often associated with lymphocytes, eosinophils, macrophages, and giant cells. BRAF mutations, usually V600E, have been reported in 40%-70% of cases, and recently, MAP2K1 mutations have been reported in BRAF-negative cases. We assessed 50 cases of LCH for BRAF mutations and assessed a subset of cases for MAP2K1 mutations. The study group included 28 men and 22 women (median age, 36.5 years; range, 1-78 years). BRAF V600E mutation was detected in 8 (16%) cases including 3 (30%) skin, 2 (11%) bone, 1 (50%) colon, 1 (20%) lung, and 1 (33%) extradural, intracranial mass. MAP2K1 mutations were detected in 6 of 13 (46%) BRAF-negative cases including 2 (100%) lymph node, 2 (50%) bone, 1 (25%) skin, and 1 (100%) orbit. Patients with BRAF mutation were younger than patients with wild-type BRAF (median age, 28 versus 38 years; P = .026). The median age of MAP2K1-mutated patients was 34.5 years, similar to patients without MAP2K1 mutation (41 years; P = .368). In agreement with 2 recent studies, we showed a high frequency of MAP2K1 mutations in BRAF-negative LCH cases. Unlike other studies, the overall frequency of BRAF mutation in this cohort is substantially lower than what has been reported in pediatric patients, perhaps because most patients in this study were adults. Moreover, we showed a high concordance between mutational and immunohistochemical analysis for BRAF mutation. There was no statistically significant association between BRAF or MAP2K1 mutation and anatomic site, unifocal versus multifocal presentation, or clinical outcome. Published by Elsevier Inc.

  7. Evolving radiological features of hypothalamo-pituitary lesions in adult patients with Langerhans cell histiocytosis (LCH)

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    Makras, P. [Athens General Hospital, Department of Endocrinology and Diabetes, Athens (Greece); Athens General Hospital, Department of Radiology, Athens (Greece); Samara, C.; Antoniou, M.; Nikolakopoulou, Z. [Athens Hospital, 9. Pulmonary Department, Athens (Greece); Zetos, A. [General Hospital, Department of Pathology, Athens (Greece); Papadogias, D.; Piaditis, G.; Kaltsas, G.A. [Athens General Hospital, Department of Endocrinology and Diabetes, Athens (Greece); Toloumis, G. [Athens General Hospital, Department of Radiology, Athens (Greece); Andreakos, E.; Kontogeorgos, G.

    2006-01-01

    Langerhans cell histiocytosis (LCH) is a rare, systemic disease caused by monoclonal expansion of dendritic cells that shows a particular predilection for the hypothalamic-pituitary system (HPS). We studied the function (anterior and posterior pituitary hormonal secretion) and morphology using magnetic resonance imaging (MRI) of the HPS in 17 adult patients (seven males, median age 35 years, range 18-59 years) with multisystem LCH. We also evaluated the evolution of structural HPS abnormalities in relation to pituitary function and response to treatment in 12 of these patients during a median follow-up period of 3.75 years (range 1.5-10 years). Of the 17 patients, 14 (82%) had abnormal HPS imaging, and 12 (70%) had more than one area involved. Lack of the bright spot of the posterior pituitary lobe was typically found in all patients with the diagnosis of diabetes insipidus (DI). Eight patients (47%) had infundibular enlargement, six (35%) pituitary infiltration, four (24%) partially or completely empty sella, three (18%) hypothalamic involvement, and two (12%) infundibular atrophy. DI was found in 16 patients (94%) and anterior pituitary hormonal deficiency (APHD) in 10 patients (59%); two patients had single (12%) and 8 (47%) multiple APHD. During the follow-up period there was improvement of the initially demonstrated HPS pathology in seven (47%) patients, and five (33%) of them had received at least one form of treatment. APHD and DI persisted in all patients except in one in whom established gonadotrophin deficiency recovered. In summary, DI and APHD are very common in patients with multisystem LCH and are almost always associated with abnormal HPS imaging. (orig.)

  8. Spontaneous Remission of Severe Systemic Langerhans Cell Histiocytosis with Bladder Involvement: A Case Study

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    Isotta M. Magaton

    2017-10-01

    Full Text Available Background: The clinical presentation of Langerhans cell histiocytosis (LCH is heterogeneous ranging from single-organ involvement to systemic disease causing substantial morbidity and mortality. We describe an unusual course of severe multisystem LCH with spontaneous remission. Case Presentation: We report on a 45-year-old Caucasian woman with cervical cancer, FIGO stage IVB. Five months after the end of combined radiochemotherapy and brachytherapy, the patient was readmitted because of severe dysuria. Sterile leukocyturia was seen, and cystoscopy revealed only 3 unspecific small mucosal lesions compatible with postradiation cystitis. Incidentally, a computed tomography (CT scan of the body showed diffuse micronodular and cystic lesions in lungs and hypodense lesions in the liver. Biopsies revealed infiltrations of CD1a and Langerin (CD207-positive histiocytes in the lung, liver, and bladder. Additionally, positron emission tomography-CT (PET-CT was compatible with bone involvement. Retrospective analysis revealed that the increase in alkaline phosphatase might have been a surrogate of bone marrow infiltration with osseous activity. Repeated pneumothoraces occurred, and only one course of vinblastine-prednisolone could be applied. Despite ongoing tobacco consumption and without further therapy, PET-CT showed considerable remission 2 months later. However, despite stable remission, documented by serial PET and conventional CT scans, persistent infiltration of the bladder by Langerhans histiocytes could still be demonstrated 17 months later. Unfortunately, cervical cancer recurred and progressed. Conclusion: Multisystem LCH may rapidly occur, may be oligosymptomatic and, even in high-risk cases, remission without specific therapy might occur. Whether alkaline phosphatase might be a surrogate to monitor osseous disease activity has to be further explored.

  9. Selective CT for PET/CT: dose reduction in Langerhans cell histiocytosis

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    Gelfand, Michael J.; Sharp, Susan E. [Cincinnati Children' s Hospital Medical Center, Section of Nuclear Medicine, Department of Radiology, Cincinnati, OH (United States); Palumbo, Joseph S. [Cincinnati Children' s Hospital Medical Center, Cancer and Blood Diseases Institute, Department of Pediatrics, Cincinnati, OH (United States)

    2014-08-23

    In Langerhans cell histiocytosis (LCH), FDG PET demonstrates active disease in bone. Other imaging modalities show the effects of bone destruction by LCH. To evaluate a selective CT method for reducing effective dose from FDG PET/CT in LCH, using whole-body modified attenuation correction CT at extremely low exposure settings, with repeat selective limited-volume CT at typical localization settings. Fifty-one PET/CT scans were performed in 23 LCH patients, median patient age 8.5 years (range: 1-25 years). Thirty-four were performed with modified attenuation correction CT settings, with bed positions (excluding head and neck) repeated at localization CT settings in regions with abnormal or difficult to interpret PET findings. Of 34 modified attenuation correction PET/CT scans, 10 required repeat localization CT of 1 to 3 bed positions (total: 17 bed positions). Lytic bone lesions were easily recognized at modified attenuation correction settings. Calculated average effective dose for the 34 whole-body CT scans at modified attenuation correction settings was 1.65 mSv. Average effective dose per patient for repeat imaging of 17 bed positions at localization settings was 1.19 mSv. Average total effective dose from CT for all 34 scans performed at the modified attenuation correction CT settings, including the 10 repeat localization CT scans, was 2.0 mSv. High-quality PET scans were consistently obtained with reduced FDG-administered activities of 3.7 MBq/kg (0.10 mCi/kg). In active LCH, abnormal FDG uptake was seen in all lytic bone lesions ≥9 mm, including cranial vault lesions. Substantial reduction in effective dose is possible using selective CT techniques for FDG PET/CT. (orig.)

  10. Langerhans cell histiocytosis: A neoplastic disorder driven by Ras-ERK pathway mutations.

    Science.gov (United States)

    Tran, Gary; Huynh, Thy N; Paller, Amy S

    2018-03-01

    Langerhans cell histiocytosis (LCH) is a disorder of myeloid neoplasia of dendritic cells that affects 1 in 200,000 children <15 years of age and even fewer adults. LCH presents with a spectrum of clinical manifestations. High-risk stratification is reserved for infiltration of blood, spleen, liver, and lungs. After decades of debate on the disease pathogenesis, a neoplastic mechanism is now favored on the basis of LCH cell clonality, rare cases of familial clustering, and recent evidence of mutations involving the Ras/Raf/MEK (mitogen-activated protein kinase kinase)/ERK (extracellular signal-regulated kinase) pathway in lesional biopsy specimens. Somatic mutations are most often found in BRAF (BRAF V600E in 47.1% of reported patients) and MAP2K1 (21.7%) and uncommonly found in MAP3K1 or ARAF. Increased levels of phospho-ERK in lesional tissue, activation of Ras/Raf/MEK/ERK signaling with these mutations in vitro, and the mutual exclusivity of these mutations in a given patient suggest a central role for activation of the Ras/Raf/MEK/ERK oncogenic pathway in LCH. Immunohistochemical assessment of lesional tissue using the VE1 BRAF V600E mutation-specific antibody can serve as a screening tool for BRAF V600E -positive LCH. Case reports suggest that BRAF V600E -positive LCH unresponsive to standard therapy might respond to B-Raf-MEK pathway inhibition, but rigorous randomized clinical trials have yet to be performed. Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  11. An unusual case of adult-onset multi-systemic Langerhans cell histiocytosis with perianal and incident thyroid involvement

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    Ozen Oz Gul

    2017-02-01

    Full Text Available Langerhans cell histiocytosis (LCH is a rare sporadic disease characterized by histiocytic neoplastic infiltration of various organ systems and a wide spectrum of clinical manifestations, ranging from benign and self-limiting to lethal. Herein, we report a rare case of adult-onset multi-systemic LCH in a 36-year-old male patient with an initial perianal presentation and incidental finding of subsequent thyroid gland involvement in the follow-up period. The patient with a history of perianal LCH treated with surgical excision and local radiotherapy was referred to our Endocrinology Department upon detection of hypermetabolic nodular lesions in the left lateral lobe of thyroid gland on positron emission tomography–computed tomography (PET/CT scan in the nineth month of follow-up. Current evaluation revealed euthyroid status, a hypoechoic solid lesion of 13 × 9 mm in size with irregular borders in the left thyroid lobe on thyroid USG and cytologic assessment of thyroid nodule. The patient was diagnosed with suspected, oncocytic lesion, Hashimoto thyroiditis or LCH. The patient underwent total thyroidectomy and pathological assessment confirmed the diagnosis of Langerhans cell histiocytosis. Assessments in the sixth month of postoperative follow-up revealed euthyroid status with no thyroid tissue remnants or pathological lymph node on thyroid USG. In view of the multifocal lesions indicating multi-system disease, a systemic chemotherapy protocol with combination of prednisone (PRED and vinblastine (VBL has been planned by the hematology department.

  12. A cell-based fascin bioassay identifies compounds with potential anti-metastasis or cognition-enhancing functions

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    Robert Kraft

    2013-01-01

    The actin-bundling protein fascin is a key mediator of tumor invasion and metastasis and its activity drives filopodia formation, cell-shape changes and cell migration. Small-molecule inhibitors of fascin block tumor metastasis in animal models. Conversely, fascin deficiency might underlie the pathogenesis of some developmental brain disorders. To identify fascin-pathway modulators we devised a cell-based assay for fascin function and used it in a bidirectional drug screen. The screen utilized cultured fascin-deficient mutant Drosophila neurons, whose neurite arbors manifest the ‘filagree’ phenotype. Taking a repurposing approach, we screened a library of 1040 known compounds, many of them FDA-approved drugs, for filagree modifiers. Based on scaffold distribution, molecular-fingerprint similarities, and chemical-space distribution, this library has high structural diversity, supporting its utility as a screening tool. We identified 34 fascin-pathway blockers (with potential anti-metastasis activity and 48 fascin-pathway enhancers (with potential cognitive-enhancer activity. The structural diversity of the active compounds suggests multiple molecular targets. Comparisons of active and inactive compounds provided preliminary structure-activity relationship information. The screen also revealed diverse neurotoxic effects of other drugs, notably the ‘beads-on-a-string’ defect, which is induced solely by statins. Statin-induced neurotoxicity is enhanced by fascin deficiency. In summary, we provide evidence that primary neuron culture using a genetic model organism can be valuable for early-stage drug discovery and developmental neurotoxicity testing. Furthermore, we propose that, given an appropriate assay for target-pathway function, bidirectional screening for brain-development disorders and invasive cancers represents an efficient, multipurpose strategy for drug discovery.

  13. Graham Greene’s Journey Without Maps and the Fascination of the Abomination

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    John AIREY

    2009-07-01

    Full Text Available Le narrateur de ce récit de voyage se révèle fasciné par ce qui est abominable : maladies, crimes de guerre, cruauté et cauchemars sont les principaux exemples dans le texte. A ce sujet, il ouvre un dialogue critique avec ses deux principaux hypotextes, Heart of Darkness de Conrad et surtout The Blue Book, publication du gouvernement Britannique : l’abominable serait donc polysémique. Son voyage fait de l’arrière pays ‘primitif’ du Libéria un ‘texte’ scriptible. Parallèlement, il utilise la partie du pays explorée comme métaphore de l’inconscient : de la sorte il compare son périple au ‘voyage’ de Freud. La ‘civilisation’, souvent symbolisée par le Christianisme dans le récit, ferait fausse route car elle serait fondée sur le refoulement, voir la déformation d’une partie de la réalité : être sain d’esprit serait refuser d’accomplir ces actions et s’engager dans un dialogue avec ‘le père politique’ (Barthes. Le lecteur est incité à avouer sa fascination pour cette zone ténébreuse et donc à entreprendre sa propre exploration.The narrator of this travel book shows himself to be fascinated by what is abominable: disease, war crimes, cruelty and nightmares are the main examples in the text. He opens a critical dialogue on this subject with his two main hypotexts, Conrad’s Heart of Darkness and, especially, The Blue Book, a British government publication; the abomination is found to be polysemic. His journey transforms the supposedly primitive Liberian hinterland into a writerly text (Barthes. At the same time, the narrator uses the part of the country he is exploring as a metaphor for the unconscious; hence he compares his voyage to Freud’s ‘journey’. ‘Civilisation’, of which Christianity is often used as a symbol in the text, is on the wrong track according to the narrator since it is based on the repression, if not the distortion, of a part of reality. To be sane is to

  14. Tattoo as art, the drivers behind the fascination and the decision to become tattooed.

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    Kierstein, Liz; Kjelskau, Kari C

    2015-01-01

    For many people, getting a tattoo is like purchasing art, and many professional and famous tattooists are artists who are acknowledged by colleagues and authorities. The history of tattooing goes back for thousands of years, and the reasons for getting tattooed are many. These permanent markings are always personal, they can be plain or elaborate, and they serve as amulets, healing and status symbols, declarations of love, signs of religion, adornments and even forms of punishment. Drivers behind the fascination of acquiring a tattoo may fall into four main groups, namely healing, affiliation, art and fashion. © 2015 S. Karger AG, Basel.

  15. Expansion of regulatory T cells in patients with Langerhans cell histiocytosis.

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    Brigitte Senechal

    2007-08-01

    Full Text Available Langerhans cell histiocytosis (LCH is a rare clonal granulomatous disease that affects mainly children. LCH can involve various tissues such as bone, skin, lung, bone marrow, lymph nodes, and the central nervous system, and is frequently responsible for functional sequelae. The pathophysiology of LCH is unclear, but the uncontrolled proliferation of Langerhans cells (LCs is believed to be the primary event in the formation of granulomas. The present study was designed to further investigate the nature of proliferating cells and the immune mechanisms involved in the LCH granulomas.Biopsies (n = 24 and/or blood samples (n = 25 from 40 patients aged 0.25 to 13 y (mean 7.8 y, were studied to identify cells that proliferate in blood and granulomas. We found that the proliferating index of LCs was low ( approximately 1.9%, and we did not observe expansion of a monocyte or dendritic cell compartment in patients. We found that LCH lesions were a site of active inflammation, tissue remodeling, and neo-angiogenesis, and the majority of proliferating cells were endothelial cells, fibroblasts, and polyclonal T lymphocytes. Within granulomas, interleukin 10 was abundant, LCs expressed the TNF receptor family member RANK, and CD4(+ CD25(high FoxP3(high regulatory T cells (T-regs represented 20% of T cells, and were found in close contact with LCs. FoxP3(+ T-regs were also expanded compared to controls, in the blood of LCH patients with active disease, among whom seven out of seven tested exhibited an impaired skin delayed-type hypersensitivity response. In contrast, the number of blood T-regs were normal after remission of LCH.These findings indicate that LC accumulation in LCH results from survival rather than uncontrolled proliferation, and is associated with the expansion of T-regs. These data suggest that LCs may be involved in the expansion of T-regs in vivo, resulting in the failure of the host immune system to eliminate LCH cells. Thus T-regs could be

  16. B-RAF mutant alleles associated with Langerhans cell histiocytosis, a granulomatous pediatric disease.

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    Takeshi Satoh

    Full Text Available Langerhans cell histiocytosis (LCH features inflammatory granuloma characterised by the presence of CD1a+ dendritic cells or 'LCH cells'. Badalian-Very et al. recently reported the presence of a canonical (V600EB-RAF mutation in 57% of paraffin-embedded biopsies from LCH granuloma. Here we confirm their findings and report the identification of two novel B-RAF mutations detected in LCH patients.Mutations of B-RAF were observed in granuloma samples from 11 out of 16 patients using 'next generation' pyrosequencing. In 9 cases the mutation identified was (V600EB-RAF. In 2 cases novel polymorphisms were identified. A somatic (600DLATB-RAF insertion mimicked the structural and functional consequences of the (V600EB-RAF mutant. It destabilized the inactive conformation of the B-RAF kinase and resulted in increased ERK activation in 293 T cells. The (600DLATB-RAF and (V600EB-RAF mutations were found enriched in DNA and mRNA from the CD1a+ fraction of granuloma. They were absent from the blood and monocytes of 58 LCH patients, with a lower threshold of sequencing sensitivity of 1%-2% relative mutation abundance. A novel germ line (T599AB-RAF mutant allele was detected in one patient, at a relative mutation abundance close to 50% in the LCH granuloma, blood monocytes and lymphocytes. However, (T599AB-RAF did not destabilize the inactive conformation of the B-RAF kinase, and did not induce increased ERK phosphorylation or C-RAF transactivation.Our data confirmed presence of the (V600EB-RAF mutation in LCH granuloma of some patients, and identify two novel B-RAF mutations. They indicate that (V600EB-RAF and (600DLATB-RAF mutations are somatic mutants enriched in LCH CD1a(+ cells and absent from the patient blood. Further studies are needed to assess the functional consequences of the germ-line (T599AB-RAF allele.

  17. Langerhans cell histiocytosis associated with lymphoma: an incidental finding that is not associated with BRAF or MAP2K1 mutations.

    Science.gov (United States)

    Pina-Oviedo, Sergio; Medeiros, L Jeffrey; Li, Shaoying; Khoury, Joseph D; Patel, Keyur P; Alayed, Khaled; Cason, R Craig; Bowman, Christopher J; Yin, C Cameron

    2017-05-01

    Langerhans cell histiocytosis is characterized by a localized or systemic proliferation of Langerhans cells. BRAF mutations have been reported in 40-70% of cases and MAP2K1 mutations have been found in BRAF-negative cases, supporting that Langerhans cell histiocytosis is a true neoplasm, at least in mutated cases. In a small subset of patients, Langerhans cell histiocytosis is detected incidentally in a biopsy involved by lymphoma. These lesions are usually minute and rarely have been assessed for mutations. We assessed for BRAF and MAP2K1 mutations in seven cases of Langerhans cell histiocytosis detected incidentally in biopsies involved by lymphoma. We performed immunohistochemical analysis for phosphorylated (p)-ERK. There were four men and three women (median age, 54 years; range, 28-84). The biopsies included lymph nodes (n=6) and chest wall (n=1). The lymphomas included five classical Hodgkin lymphoma, one mantle cell lymphoma, and one angioimmunoblastic T-cell lymphoma. All cases were negative for BRAF V600E and MAP2K1 mutations. Nevertheless, three of seven cases showed ERK activation as shown by expression of p-ERK. We performed mutation analysis using a panel of 134 commonly mutated genes (including BRAF and MAP2K1) by next-generation sequencing on three cases, including two cases positive for p-ERK by immunohistochemistry. No mutations were detected in any of the three cases assessed. Six patients received therapy appropriate for their lymphoma. With a median follow-up of 21 months (range, 6-89), no patients developed disseminated or recurrent Langerhans cell histiocytosis. We conclude that lymphoma-associated Langerhans cell histiocytosis is a clinically benign process that is not associated with BRAF V600E or MAP2K1 mutations and, as suggested by others, the designation Langerhans cell hyperplasia may be more appropriate. Nevertheless, the expression of p-ERK in three cases suggests that the RAS-RAF-MAP2K-ERK pathway is activated, perhaps by non

  18. Langerhans’ cell histiocytosis involving posterior elements of the dorsal spine: An unusual cause of extradural spinal mass in an adult

    Science.gov (United States)

    Tyagi, Devendra K.; Balasubramaniam, Srikant; Savant, Hemant V.

    2011-01-01

    Langerhans cell histiocytosis (LCH) is a clonal proliferation of Langerhans cells occurring as an isolated lesion or as part of a systemic proliferation. It is commoner in children younger than 10 years of age with sparing of the posterior elements in more than 95% of cases. We describe a case of LCH in an adult female presenting with paraplegia. MRI revealed a well-defined extradural contrast enhancing mass at D2-D4 vertebral level involving the posterior elements of spine. D2-5 laminectomy with excision of lesion was performed which lead to marked improvement of patients neurological status. Histopathology was suggestive of eosinophilic granuloma. We describe the case, discuss its uniqueness and review the literature on this rare tumor presentation. PMID:23125497

  19. Langerhans' cell histiocytosis involving posterior elements of the dorsal spine: An unusual cause of extradural spinal mass in an adult.

    Science.gov (United States)

    Tyagi, Devendra K; Balasubramaniam, Srikant; Savant, Hemant V

    2011-07-01

    Langerhans cell histiocytosis (LCH) is a clonal proliferation of Langerhans cells occurring as an isolated lesion or as part of a systemic proliferation. It is commoner in children younger than 10 years of age with sparing of the posterior elements in more than 95% of cases. We describe a case of LCH in an adult female presenting with paraplegia. MRI revealed a well-defined extradural contrast enhancing mass at D2-D4 vertebral level involving the posterior elements of spine. D2-5 laminectomy with excision of lesion was performed which lead to marked improvement of patients neurological status. Histopathology was suggestive of eosinophilic granuloma. We describe the case, discuss its uniqueness and review the literature on this rare tumor presentation.

  20. Central diabetes insipidus as a very late relapse limited to the pituitary stalk in Langerhans cell histiocytosis.

    Science.gov (United States)

    Nakagawa, Shunsuke; Shinkoda, Yuichi; Hazeki, Daisuke; Imamura, Mari; Okamoto, Yasuhiro; Kawakami, Kiyoshi; Kawano, Yoshifumi

    2016-07-01

    Central diabetes insipidus (CDI) and relapse are frequently seen in multifocal Langerhans cell histiocytosis (LCH). We present two females with multifocal LCH who developed CDI 9 and 5 years after the initial diagnosis, respectively, as a relapse limited to the pituitary stalk. Combination chemotherapy with cytarabine reduced the mass in the pituitary stalk. Although CDI did not improve, there has been no anterior pituitary hormone deficiency (APHD), neurodegenerative disease in the central nervous system (ND-CNS) or additional relapse for 2 years after therapy. It was difficult to predict the development of CDI in these cases. CDI might develop very late in patients with multifocal LCH, and therefore strict follow-up is necessary, especially with regard to symptoms of CDI such as polydipsia and polyuria. For new-onset CDI with LCH, chemotherapy with cytarabine might be useful for preventing APHD and ND-CNS.

  1. Langerhans′ cell histiocytosis involving posterior elements of the dorsal spine: An unusual cause of extradural spinal mass in an adult

    Directory of Open Access Journals (Sweden)

    Devendra K Tyagi

    2011-01-01

    Full Text Available Langerhans cell histiocytosis (LCH is a clonal proliferation of Langerhans cells occurring as an isolated lesion or as part of a systemic proliferation. It is commoner in children younger than 10 years of age with sparing of the posterior elements in more than 95% of cases. We describe a case of LCH in an adult female presenting with paraplegia. MRI revealed a well-defined extradural contrast enhancing mass at D2-D4 vertebral level involving the posterior elements of spine. D2-5 laminectomy with excision of lesion was performed which lead to marked improvement of patients neurological status. Histopathology was suggestive of eosinophilic granuloma. We describe the case, discuss its uniqueness and review the literature on this rare tumor presentation.

  2. [Analysis of clinical, iconographical and pathological characteristics, prognosis and treatment methods for 35 cases of Langerhans cell histiocytosis].

    Science.gov (United States)

    Yang, Hua; Han, Xiao-Ping; Li, Bao-Jing; Sun, Lu; Zhu, Hai-Yan; Li, Fei; Wang, Quan-Shun; Huang, Wen-Rong; Bo, Jian; Zhao, Yu; Li, Hong-Hua; Wang, Shu-Hong; Yu, Li; Jing, Yu

    2014-08-01

    Purpose of this study was to analyse the characteristics of clinical, iconographical, pathological and treatment methods of Langerhans cell histiocytosis (LCH), so as to improve the diagnosis and treatment level of this disease. The clinical data of 35 LCH patients were studied retrospectively. These patients were divided into 2 groups according to age clinical symptoms were analysed and the signs, imageology and pathology manifestation and treatment results were evaluated. The results showed that LCH clinical manifestations were diverse and complex. Surgical treatment for patients with single system involvement of LCH was better than that of multi-system involvement of LCH (MS-LCH). For the latter, combined chemotherapy effects was better. After 3-year follow-up, 1-year OS was 94% ± 4%, 2-years OS was 91% ± 5%, 3-year OS was 86% ± 7%. 3 years OS of group <14 years old and ≥ 14 years old was 94% ± 6% and 81% ± 10% respectively. The OS of former was better than that of the later, but because a small number of cases, this difference was not statistically significant. It is concluded that LCH is easy to be misdiagnosed, the pathological biopsy is the gold standard of LCH diagnosis. The PET-CT can be of great help in identifying stages and finding lesion areas of the disease. Pulmonary Langerhans cell histiocytosis (PLCH) is more common in adult. Combined chemotherapy can improve the prognosis of the patients. The treatment methods should be choosed according to the stage and classification of disease.

  3. Un refus fasciné – L’ambivalence du religieux chez Tabucchi

    OpenAIRE

    De Poli, Fabrice

    2012-01-01

    Quand on lui demande quels livres il emporterait sur une île déserte, Tabucchi répond : « L’un de ceux-là, bien que je sois agnostique, serait, sans aucun doute, les Évangiles […], livre mystérieux, indéchiffrable même » (AE, p. 82). Quelle place peuvent prendre dès lors la religion et le religieux chez un auteur non religieux mais fasciné par les mystères et notamment par le plus grand de tous ? Si Tabucchi, qui se définit tour à tour agnostique, sceptique ou non croyant, récuse le dogmatism...

  4. Neuroendocrine tumors: fascination and infrequency Tumores neuroendocrinos: fascinación e infrecuencia

    Directory of Open Access Journals (Sweden)

    M. J. Varas Lorenzo

    2009-03-01

    Full Text Available In this article, I review and update of gastro-entero-pancreatic neuroendocrine tumors, which so much fascination have risen among healthcare providers on grounds of their infrequency, hormonal syndromes, and high survival rate, is performed based on references from the past fifteen years.Se efectúa una revisión y puesta al día, basándose en citas bibliográficas de los últimos quince años, de los tumores neuroendocrinos gastroenteropancreáticos, que tanta fascinación han provocado en el estamento médico por su infrecuencia, síndromes hormonales y supervivencia elevada.

  5. Fascination and isolation: a grounded theory exploration of unusual sensory experiences in adults with Asperger syndrome.

    Science.gov (United States)

    Smith, Richard S; Sharp, Jonathan

    2013-04-01

    Unusual sensory experiences are commonly seen in people with Asperger syndrome (AS). They correlate with functional impairments and cause distress. The current study investigates how these experiences have affected nine adults with AS's lives, as well as the coping strategies utilised. Semi-structured interviews were conducted using Instant Messaging software. Data were analysed using Grounded Theory. A number of inter-related categories and focused codes were identified. The categories included heightened senses, sensory stress, the stress avalanche, moderating factors, coping strategies, other people, self-acceptance, fascination, and isolation. A model was constructed as to how these categories and codes interact. How these findings link with previous research into autism spectrum disorders is discussed. Implications for services and future research are also made.

  6. Fascination and Social Togetherness–-Discussions about Spice Smoking on a Swedish Internet Forum

    Directory of Open Access Journals (Sweden)

    Anette Kjellgren

    2013-01-01

    Full Text Available Spice is a smoking mixture containing synthetic cannabinoids with psychoactive effects similar to herbal cannabis. It is sold on the Internet and has become popular among young people. The purpose of the present study was to investigate experiences of intoxication induced by Spice, as described on a Swedish internet-based discussion forum. A systematic search yielded 40 reports, which were analyzed using phenomenological method. A total of 7 themes (composed of 27 categories emerged from the analysis: 1. Spice use as social ritual; 2. Social secretiveness; 3. Intoxication remarks; 4. Well-being and elation; 5. Altered perception of reality; 6. Fears and coping; 7. Unpleasant physical effects. The results show that smoking was a social activity mostly carried out in small peer-groups, and that the substances induced strong intoxication with both positive and negative effects. Despite fears and unpleasant effects, the intoxication was often considered fascinating and rewarding.

  7. Quirky quarks. A cartoon guide to the fascinating realm of physics

    Energy Technology Data Exchange (ETDEWEB)

    Bahr, Benjamin; Lemmer, Boris; Piccolo, Rina

    2016-07-01

    Do you love quantum physics, cosmology, and the humor behind the popular television show The Big Bang Theory? Have you been on the lookout for a fun, non-technical explanation of the science behind things like time travel, wormholes, antimatter, and dark energy? You'll find all of that, and more, inside this fact-filled, cartoon-packed book. In Quirky Quarks: A Cartoon Guide to the Fascinating Realm of Physics you'll get: The latest science behind the mysteries of our universe explained in common everyday language. A major dose of cartoons, comics, and humor. A good grasp on the often-bizarre nature of reality. Start reading and you'll find that hard science does not have to be hard. Whether you're a teacher, a physicist, or just a lover of the curious, this is the book that delivers the facts in an engaging and entertaining cartoon world inhabited by two dogs, a cat, and some very quirky quarks which you might know from The Particle Zoo. With cutting edge science articles by physicists Boris Lemmer and Benjamin Bahr, and drawings by cartoonist Rina Piccolo, this may be the most fun science reading you're likely to find out there.

  8. High resolution gamma-ray spectroscopy and the fascinating angular momentum realm of the atomic nucleus

    Science.gov (United States)

    Riley, M. A.; Simpson, J.; Paul, E. S.

    2016-12-01

    In 1974 Aage Bohr and Ben Mottelson predicted the different ‘phases’ that may be expected in deformed nuclei as a function of increasing angular momentum and excitation energy all the way up to the fission limit. While admitting their picture was highly conjectural they confidently stated ‘...with the ingenious experimental approaches that are being developed, we may look forward with excitement to the detailed spectroscopic studies that will illuminate the behaviour of the spinning quantised nucleus’. High resolution gamma-ray spectroscopy has indeed been a major tool in studying the structure of atomic nuclei and has witnessed numerous significant advances over the last four decades. This article will select highlights from investigations at the Niels Bohr Institute, Denmark, and Daresbury Laboratory, UK, in the late 1970s and early 1980s, some of which have continued at other national laboratories in Europe and the USA to the present day. These studies illustrate the remarkable diversity of phenomena and symmetries exhibited by nuclei in the angular momentum-excitation energy plane that continue to surprise and fascinate scientists.

  9. The fascination for the circle. Commentary on the paragraphs 13, 14 and 15 of The birth of tragedy

    Directory of Open Access Journals (Sweden)

    Julián Santos Guerrero

    2014-07-01

    Full Text Available The article tries to fix the attention on the functioning of the figure of the circle inside the thought of the young Nietzsche of The birth of tragedy.  At the same time, in it there is a thesis about the origin of the fascination that the above mentioned figure exercises in the Nietzschean text

  10. Coincident expression of the chemokine receptors CCR6 and CCR7 by pathologic Langerhans cells in Langerhans cell histiocytosis.

    Science.gov (United States)

    Fleming, Mark D; Pinkus, Jack L; Fournier, Marcia V; Alexander, Sarah W; Tam, Carmen; Loda, Massimo; Sallan, Stephen E; Nichols, Kim E; Carpentieri, David F; Pinkus, Geraldine S; Rollins, Barrett J

    2003-04-01

    It has been suggested that a switch in chemokine receptor expression underlies Langerhans cell migration from skin to lymphoid tissue. Activated cells are thought to down-regulate CCR6, whose ligand macrophage inflammatory protein-3 alpha (MIP-3 alpha)/CCL20 is expressed in skin, and up-regulate CCR7, whose ligands are in lymphoid tissues. In Langerhans cell histiocytosis (LCH), pathologic Langerhans cells (LCs) accumulate in several tissues, including skin, bone, and lymphoid organs. We have examined 24 LCH cases and find that pathologic LCs expressed CCR6 and CCR7 coincidentally in all cases. Furthermore, MIP-3 alpha/CCL20 is expressed by keratinocytes in involved skin and by macrophages and osteoblasts in involved bone. Expression of CCR6 by pathologic LCs may contribute to their accumulation in nonlymphoid organs such as skin and bone, whereas CCR7 expression may direct them to lymphoid tissue. Histiocytes in Rosai-Dorfman disease and hemophagocytic syndrome also coexpressed CCR6 and CCR7, suggesting that this may be a general attribute of abnormal histiocytes.

  11. Langerhans cell histiocytosis is a neoplasm and consequently its recurrence is a relapse: In memory of Bob Arceci.

    Science.gov (United States)

    Egeler, R Maarten; Katewa, Satyendra; Leenen, Pieter J M; Beverley, Peter; Collin, Matthew; Ginhoux, Florent; Arceci, Robert J; Rollins, Barrett J

    2016-10-01

    Langerhans cell histiocytosis (LCH) remains a poorly understood disorder with heterogeneous clinical presentations characterized by focal or disseminated lesions that contain excessive CD1a+ langerin+ cells with dendritic cell features known as "LCH cells." Two of the major questions investigated over the past century have been (i) the origin of LCH cells and (ii) whether LCH is primarily an immune dysregulatory disorder or a neoplasm. Current opinion is that LCH cells are likely to arise from hematopoietic precursor cells, although the stage of derailment and site of transformation remain unclear and may vary in patients with different extent of disease. Over the years, evidence has provided the view that LCH is a neoplasm. The demonstration of clonality of LCH cells, insufficient evidence alone for neoplasia, is now bolstered by finding driver somatic mutations in BRAF in up to 55% of patients with LCH, and activation of the RAS-RAF-MEK-ERK (where MEK and ERK are mitogen-activated protein kinase and extracellular signal-regulated kinase, respectively) pathway in nearly 100% of patients with LCH. Herein, we review the evidence that recurrent genetic abnormalities characterized by activating oncogenic mutations should satisfy prerequisites for LCH to be called a neoplasm. As a consequence, recurrent episodes of LCH should be considered relapsed disease rather than disease reactivation. Mapping the complete genetic landscape of this intriguing disease will provide additional support for the conclusion that LCH is a neoplasm and is likely to provide more potential opportunities for molecularly targeted therapies. © 2016 Wiley Periodicals, Inc.

  12. Square-wave jerks and smooth pursuit impairment as subtle early signs of brain involvement in Langerhans' cell histiocytosis.

    Science.gov (United States)

    Anagnostou, Evangelos; Papageorgiou, Sokratis G; Potagas, Constantinos; Alexakis, Theodoros; Kalfakis, Nikolaos; Anastasopoulos, Dimitri

    2008-03-01

    Central nervous system (CNS) involvement in Langerhans' cell histiocytosis (LCH) has been described as a progressive neurological disorder marked by motor and cognitive decline. Detailed analysis of ocular motor abnormalities is lacking. We report on a 60-year-old male with histologically confirmed LCH who developed oscillopsia and gait ataxia over a 1-year period. Eye movements recorded with infrared oculography revealed a high rate of square-wave jerks (SWJ) with frequencies of 41 min(-1) on average and amplitudes between 1 degrees and 7 degrees , as well as marked impairment of smooth tracking of sinusoidally moving targets. Furthermore, static posturography disclosed increased body sway, with an abnormally high sway path. The initial brain MRI was unremarkable. Due to the presumed cerebellar dysfunction we performed a second MRI 1 year later that disclosed deep cerebellar lesions compatible with LCH relapse within the CNS. The abnormal high SWJ rate and the impaired smooth pursuit performance correctly heralded later involvement of the cerebellum anticipating lesion appearance in the MRI.

  13. Progressive Langerhans cell histiocytosis in an infant with Klinefelter syndrome successfully treated with allogeneic bone marrow transplantation.

    Science.gov (United States)

    Frost, J D; Wiersma, S R

    1996-11-01

    We describe successful treatment of an infant with progressive Langerhans cell histiocytosis (LCH) with allogeneic bone marrow transplantation (BMT), and discuss a chromosomal abnormality discovered in his LCH-affected tissue. A 4-month-old male infant with a seborrheic-appearing rash, respiratory collapse, and spontaneous pneumothorax is presented. LCH was diagnosed with primary involvement of skin and lungs. His disease progressed despite aggressive multiagent chemotherapy that included high-dose methylprednisolone, vinblastine, cyclophosphamide, methotrexate, 2-chlorodeoxyadenosine, and etoposide. The patient was successfully treated with myeloblative therapy and low-dose total body irradiation followed by allogeneic BMT at the age of 16 months, at which time he had multisystem involvement. One hundred percent 47XXY/14p+ cells were identified from a lung biopsy; peripheral blood chromosomal analysis demonstrated mosaic 47XXY/14p+, and normal 46XY. Allogeneic BMT may be used successfully in the treatment of refractory, progressive LCH in infants, who are at highest risk of mortality. The cytogenetic association between Klinefelter syndrome and LCH has not been described previously. Cytogenetic analysis of other patients with LCH may be beneficial in determining a genetic association between LCH and Klinefelter syndrome and/or abnormalities of chromosome 14.

  14. Coincidence of Rhinoscleroma and Rosai-Dorfman disease (Sinus histiocytosis with massive lymphadenopathy: Report of a case

    Directory of Open Access Journals (Sweden)

    Naraghi M

    2002-05-01

    Full Text Available A 35-year-old man was admitted because of a 2-year history of nasal obstrction, a nasopharyngeal mass, malaise, and massive cervical lymphadenopathy. Nasal symptoms and nasopharygeal mass were due to rhinoscleroma that was confirmed by an incisional biopsy and culture. The patient underwent cervical lymph node biopsy and culture. The patient underwent cervical lymph node biopsy that revealed the tissue compatible with Rosai-Dorfman disease, also called sinus histiocytosis with massive lymphadenopathy. Rhinoscleroma was treated by a combination of excision and antibiotics. Culture became negative for Klebsiella rhinoscleromatis. Then prednisolone administered for one month and gradually tapered. Lymph nodes became small at the end of treatment. Twelve months follow-up showed no evidence of recurrence of both diseases. To the best of our knowledge, this is the first report of association of rhinoscleroma with Rosai-Dorfman disease. Association of these two rare diseases may be due to just a coincidence, or a common immunologic or microbiologic underlying factor

  15. Fever and Skin Involvement at Diagnosis Predicting the Intractable Langerhans Cell Histiocytosis: 40 Case-Series in a Single Center.

    Science.gov (United States)

    Kobayashi, Tetsuko; Koga, Yuhki; Ishimura, Masataka; Nakashima, Kentaro; Kato, Wakako; Ono, Hiroaki; Sonoda, Motoshi; Eguchi, Katsuhide; Fukano, Reiji; Honjo, Satoshi; Oda, Yoshinao; Ohga, Shouichi

    2017-12-29

    Langerhans cell histiocytosis (LCH) occurs as a clonal disease with enigmatic immune responses. LCH patients occasionally present with fever, although the significance remains elusive. We investigated the predicting factors for developing intractable disease of refractory and/or reactivated LCH. In total, 40 pediatric LCH patients managed in Kyushu University from 1998 to 2014 were enrolled. The medical records were analyzed retrospectively. Sixteen patients suffered from multisystem (MS) LCH involving risk organs (ROs) (n=4) or not (n=12). In total, 24 patients had single-system LCH affecting bone (multi n=8, single n=13), skin (n=2), or lymph node lesions (n=1). Eight patients had the intractable disease of 7 MS or 1 multibone LCH. Two patients died from MS LCH with or without RO involvement. Ten patients showed persistent fever (>38°C) at onset. Intractable cases had fever, RO and skin involvement, leukocytosis, coagulopathy, microcytic anemia, higher levels of soluble interleukin-2 receptor and C-reactive protein, more frequently at diagnosis. Multivariate analysis indicated that fever and skin lesions at diagnosis were independently associated with the intractability (odds ratio: fever, 35.5; 95% confidence interval, 3.0-1229.1; skin lesions, 24.6; 95% confidence interval, 1.9-868.7). Initial fever and skin involvement might predict the development of intractable and fatal-risk LCH even without the RO involvement.

  16. Langerhans Cell Histiocytosis (LCH): Guidelines for Diagnosis, Clinical Work-Up, and Treatment for Patients Till the Age of 18 Years

    Science.gov (United States)

    Haupt, Riccardo; Minkov, Milen; Astigarraga, Itziar; Schäfer, Eva; Nanduri, Vasanta; Jubran, Rima; Egeler, R Maarten; Janka, Gritta; Micic, Dragan; Rodriguez-Galindo, Carlos; Van Gool, Stefaan; Visser, Johannes; Weitzman, Sheila; Donadieu, Jean

    2013-01-01

    These guidelines for the management of patients up to 18 years with Langerhans cell histiocytosis (LCH) have been set up by a group of experts involved in the Euro Histio Net project who participated in national or international studies and in peer reviewed publications. Existing guidelines were reviewed and changed where new evidence was available in the literature up to 2012. Data and publications have been ranked according to evidence based medicine and when there was a lack of published data, consensus between experts was sought. Guidelines for diagnosis, initial clinical work-up, and treatment and long-term follow-up of LCH patients are presented. PMID:23109216

  17. Smart Materials in Architecture: Useful Tools with Practical Applications or Fascinating Inventions for Experimental Design?

    Science.gov (United States)

    Konarzewska, Bogusława

    2017-10-01

    For at least several decades smart or so-called intelligent materials, being the result of great advancements in material engineering, appear in architecture in different applications. Most of them are called “smart” because of their inherent properties: a real-time response to environmental stimuli. There are also those considered to be “smart” due to smart design: their original structure or the composition of their materials are in nanoscale, providing them with unique properties. Colour changes, physical states, temperature or shape–always repeatable and reversible – make these materials attractive to architects, both from a visual and a practical point of view. Their spectacular applications often inspire architects, scientists and artists to create, for instance, city displays revealing various shapes and figures according to daily weather conditions; thermochromics urban seats that reflect peoples’ presence; wallpaper with organic patterns that glow in darkness, and many others. On the other hand, more practical projects are being developed, such as “switchable” partition glass walls (that is, we can turn them on and they change their transparency while switching on or off: electrochromic glass is a good example). Other concepts include self-cleaning building envelopes; self-repairing concrete; phase-changing materials diminishing cooling loads in the buildings; energy-generating highways; materials that harden at the moment of impact thus withstanding exceptionally great forces; shape memory alloys playing the role of actuators-opening and - closing façade louvers or thin polymer films mimicking the function of living skin, adopted as a building envelope. All those projects result from the fascination of designers with the possibility to create materials and, in effect, a complex environment that is active, “flexible”, and adapts to changing conditions and users’ needs and is compatible with real, natural environments. Smart

  18. Expression of Fascin-1 on human lung cancer and paracarcinoma tissue and its relation to clinicopathological characteristics in patients with lung cancer

    Science.gov (United States)

    Zhao, Wei; Gao, Jing; Wu, Jing; Liu, Qiu-hong; Wang, Zhi-gang; Li, Hui-ling; Xing, Li-hua

    2015-01-01

    Background Lung cancer poses a severe threat to human life. Biomarkers of cancers are helpful in the diagnosis and treatment of patients with cancers. Biomarkers of lung cancers are rare, and thus deserve further research. Objective The objective of the present study was to explore the expression of Fascin-1 in human lung cancer and paracarcinoma tissue, its correlation with clinicopathological characteristics in patients with lung cancer, and study the possible relationship between Fascin-1 expression and clinical–biological behavior of lung cancer. Method This study used the MaxVision two-step immunohistochemical detection method to detect Fascin-1 expression in 84 of lung cancer and paracarcinoma tissues. This study set the expression of Fascin-1 in vascular endothelial cells as the positive control, and used phosphate buffered saline (replacing the primary antibodies) as negative control. Result Of all the 84 lung cancer tissues and paracarcinoma tissues, positive expression of the Fascin-1 protein were detected in 78 cases (92.9%) and 27 cases (32.1%), respectively, and the difference was statistically significant (P0.05). The survival times of the patients with different Fascin-1 protein-positive expressions in lung cancer tissues were statistically significant (P>0.05), while the survival times of the patients with different Fascin-1 protein-positive expressions in paracarcinoma tissues were not statistically significant (P>0.05). Conclusion In lung cancer, Fascin-1 expression was closely related to tumor invasion and metastasis, and the difference in expression of Fascin-1 had a significant effect on the survival time of the lung cancer patients. Therefore, Fascin-1 might be expected to serve as a possible potential biomarker of lung cancer. PMID:26451116

  19. 18F-FDG PET/CT in follow-up evaluation in pediatric patients with Langerhans histiocytosis.

    Science.gov (United States)

    Garcia, J R; Riera, E; Bassa, P; Mourelo, S; Soler, M

    We evaluated the impact of 18F-FDG PET/CT in identifying sites of active disease and to assess therapeutic follow up in a group of pediatric patients with Langerhans cell histiocytosis (LCH). During 2007-2013, 13 18F-FDG PET/CT studies were performed for follow-up in 7 patients with a diagnosis of LCH (4 female, 3 male; 1-12 years-old). PET findings were analyzed and correlated with the CT and MRI. Findings were also follow-up by these techniques. PET was negative in 4 patients (all diagnosed with bone lesions and one with pituitary involvement also). CT findings showed residual morphological bone lesions in all patients, and hypophysis MRI study showed no abnormal signal. PET remained negative at 10, 14, 25 and 28 months, and no new lesions on CT and MRI were detected. PET was positive in 3 patients (one with cervical lymphadenopathy and 2 with bone lesions, one also with pituitary involvement not identified by PET). CT findings showed pathological cervical lymphadenopathy (n=1), bone lesions (n=2) and also a pituitary MRI lesion (n=1). In a patient with cervical lymphadenopathy histology demonstrated LCH involvement. In the other 2 patients, PET remained positive with an increase of 18F-FDG bone uptake at 17 and 19 months. In our preliminar study, 18F-FDG PET is a useful imaging procedure, along with other diagnostic tools, for identification of active lesions. Copyright © 2017 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

  20. {sup 18}F-fluorodeoxyglucose positron emission tomography-computed tomography in the management of adult multisystem Langerhans cell histiocytosis

    Energy Technology Data Exchange (ETDEWEB)

    Obert, Julie [Universite Paris Diderot, Paris (France); Assistance Publique-Hopitaux de Paris, Centre National de Reference de l' Histiocytose Langerhansienne, Service de Pneumologie, Hopital Saint-Louis, Paris (France); Vercellino, Laetitia [Assistance Publique-Hopitaux de Paris, Service de Medecine Nucleaire, Hopital Saint-Louis, Paris (France); Van der Gucht, Axel [Universite Paris Diderot, Paris (France); Assistance Publique-Hopitaux de Paris, Service de Medecine Nucleaire, Hopital Saint-Louis, Paris (France); De Margerie-Mellon, Constance [Universite Paris Diderot, Paris (France); Assistance Publique-Hopitaux de Paris, Service de Radiologie, Hopital Saint-Louis, Paris (France); Bugnet, Emmanuelle; Lorillon, Gwenael [Assistance Publique-Hopitaux de Paris, Centre National de Reference de l' Histiocytose Langerhansienne, Service de Pneumologie, Hopital Saint-Louis, Paris (France); Chevret, Sylvie [Universite Paris Diderot, Paris (France); Assistance Publique-Hopitaux de Paris, Service de Biostatistique et Information Medicale, Hopital Saint-Louis, Paris (France); Biostatistics and Clinical Epidemiology Research Team, U1153 CRESS, Paris (France); Tazi, Abdellatif [Universite Paris Diderot, Paris (France); Assistance Publique-Hopitaux de Paris, Centre National de Reference de l' Histiocytose Langerhansienne, Service de Pneumologie, Hopital Saint-Louis, Paris (France); Biostatistics and Clinical Epidemiology Research Team, U1153 CRESS, Paris (France)

    2017-04-15

    The standard evaluation of multisystem Langerhans cell histiocytosis (LCH) includes a clinical evaluation, laboratory tests and a skeleton/skull X-ray survey, with chest high-resolution computed tomography (HRCT) in the case of pulmonary involvement. Preliminary reports suggest that {sup 18}F-fluorodeoxyglucose positron emission tomography-computed tomography ({sup 18}F-FDG PET-CT) may be useful for evaluating patients with LCH. Fourteen consecutive adult patients with multisystem LCH were included in this retrospective study, and were evaluated using standard procedures and {sup 18}F-FDG PET-CT. The two sets of findings were compared both at baseline and during follow-up. Serial HRCT and pulmonary function tests were used to evaluate outcome in patients with lung involvement. At the baseline evaluation, PET-CT identified every LCH localization found with the standard evaluation (except a mild cecum infiltration). PET-CT showed additional lesions in seven patients, mostly involving bones, and differentiated inactive from active lesions. Thyroid {sup 18}F-FDG uptake was identified in three cases. No pituitary stalk {sup 18}F-FDG uptake was observed in patients with pituitary LCH. Only 3/12 (25 %) patients with pulmonary LCH displayed moderate pulmonary {sup 18}F-FDG uptake. During follow-up, variations (≥50 % of maximum standardized uptake) in bone {sup 18}F-FDG uptake intensity were correlated with disease state and response to treatment. The absence of lung {sup 18}F-FDG uptake did not preclude lung function improvement after treatment. Except for cases with pulmonary and pituitary involvement, {sup 18}F-FDG PET-CT could replace the standard evaluation for staging of adult patients with multisystem LCH. Serial PET-CT scans are useful for evaluating treatment responses, particularly in cases with bone LCH involvement. (orig.)

  1. MRI and clinical features of Langerhans cell histiocytosis (LCH) in the pelvis and extremities: can LCH really look like anything?

    Energy Technology Data Exchange (ETDEWEB)

    Samet, Jonathan [Northwestern University Feinberg School of Medicine, Department of Medical Imaging, Ann and Robert H. Lurie Children' s Hospital of Chicago, Chicago, IL (United States); Weinstein, Joanna [Northwestern University Feinberg School of Medicine, Departments of Pediatrics, Division of Hematology/Oncology/Stem Cell Transplant, Ann and Robert H. Lurie Children' s Hospital of Chicago, Chicago, IL (United States); Fayad, Laura M. [The Johns Hopkins University School of Medicine, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States)

    2016-05-15

    To assess clinical and MRI features of Langerhans cell histiocytosis in the pelvis and extremities. The MRI and clinical features of 21 pathologically proven cases of LCH involving the pelvis and extremities were studied. Multiple characteristics of the lesions were evaluated (location, size, T1/ T2/post-contrast features, perilesional bone and soft tissue signal, endosteal scalloping, periosteal reaction, soft tissue mass, pathologic fracture). Pre-biopsy radiologic diagnoses were collected from the original clinical reports. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), temperature, and white blood cell count (WBC) were collected at the time of diagnosis when available. The locations of the LCH lesions included five humerus, four femur, five ilium, one tibia, one clavicle, and three scapula. Lesional size ranged from 1.8 to 7.1 cm, with a mean of 3.6 cm. All lesions demonstrated perilesional bone marrow edema, periosteal reaction, endosteal scalloping, and post-contrast enhancement. An associated soft tissue mass was present in 15/21 (71.4 %). Clinically, the WBC, ESR, and CRP were elevated in 2/14 (14 %), 8/12 (67 %), and 4/10 (40 %) of cases, respectively. Fever was documented in 1/15 (7 %) patients and pain was reported in 15/15 (100 %). The clinical and radiologic features of LCH in the pelvis and extremities overlap with infection and malignancy, but LCH must be considered in the differential diagnosis, as it routinely presents with aggressive MRI features, including endosteal scalloping, periosteal reaction, perilesional edema, and a soft tissue mass. Furthermore, an unknown skeletal lesion at presentation without aggressive MRI features is unlikely to represent LCH. (orig.)

  2. Importance of multi-lineage hematologic involvement and hypoalbuminemia at diagnosis in patients with "risk-organ" multi-system Langerhans cell histiocytosis.

    Science.gov (United States)

    Braier, Jorge Luis; Rosso, Diego; Latella, Antonio; Chantada, Guillermo; Ozuna, Blanca; Ripoli, Mario; Scopinaro, Marcelo

    2010-05-01

    To perform a risk factor analysis in patients with "risk organ" multi-system Langerhans cell histiocytosis at diagnosis. From 1987 to 2007, 77 patients were analyzed. A univariate analysis of the variables, age or=2 risk involved organs, hypoalbuminemia and the presence of isolated anemia, anemia with thrombocytopenia with or without leukopenia at diagnosis was performed. Statistically significant variables were combined and entered into a multivariate analysis. Fifty-six and 66 evaluable patients had hematologic and hepatic involvement at diagnosis, respectively. Among the hematologic patients, the subgroup of anemia with thrombocytopenia with or without leukopenia showed a significantly lower 5-year survival than the subgroup of isolated anemia (0.19 vs. 0.87, respectively; P=0.0001). Of all the patients, those with hypoalbuminemia had a 5-year survival of 0.16 compared with those with normal albumin levels, who had a 5-year survival of 0.65 (P<0.0001). In multivariate analysis, only anemia with thrombocytopenia with or without leukopenia and hypoalbuminemia were the independent risk factors (relative risk 3.77; confidence interval, 1.7-8.4; P<0.0011 and relative risk 2.59; confidence interval, 1.24-5.4; P<0.0112). Anemia with thrombocytopenia with or without leukopenia and hypoalbuminemia, were associated with worse prognosis in multi-system Langerhans cell histiocytosis. Other therapeutic strategies should be considered at diagnosis or early during the initial treatment for this high risk subgroup of patients.

  3. Epigenetics: A Fascinating Field with Profound Research, Clinical, & Public Health Implications

    Science.gov (United States)

    Stein, Richard A.; Davis, Devra Lee

    2012-01-01

    Epigenetics is emerging as one of the most dynamic and vibrant biomedical areas. Multiple lines of evidence confirm that inherited genetic changes alone cannot fully explain all phenotypic characteristics of live organisms, and additional factors, which are not encoded in the DNA sequence, are involved. The contribution of non-genetic factors is…

  4. Acute-phase ITIH4 levels distinguish multi-system from single-system Langerhans cell histiocytosis via plasma peptidomics.

    Science.gov (United States)

    Murakami, Ichiro; Oh, Yukiko; Morimoto, Akira; Sano, Hitoshi; Kanzaki, Susumu; Matsushita, Michiko; Iwasaki, Takeshi; Kuwamoto, Satoshi; Kato, Masako; Nagata, Keiko; Hayashi, Kazuhiko; Imashuku, Shinsaku; Gogusev, Jean; Jaubert, Francis; Oka, Takashi; Yoshino, Tadashi

    2015-01-01

    Langerhans cell histiocytosis (LCH) is a proliferative disorder in which abnormal Langerhans cell (LC)-like cells (LCH cells) intermingle with inflammatory cells. Whether LCH is reactive or neoplastic remains a controversial matter. We recently described Merkel cell polyomavirus (MCPyV) as a possible causative agent of LCH and proposed interleukin-1 loop model: LCH is a reactive disorder with an underlying oncogenic potential and we now propose to test this theory by looking for acute markers of inflammation. We detected MCPyV-DNA in the peripheral blood cells of patients with high-risk organ-type (LCH-risk organ (RO) (+)) but not those with non-high-risk organ-type LCH (LCH-RO (-)); this difference was significant. LCH-RO (-) is further classified by its involvement of either a single organ system (SS-LCH) or multiple organ systems (MS-LCH). In patients with LCH-RO (-), MCPyV-DNA sequences were present in LCH tissues, and significant differences were observed between LCH tissues and control tissues associated with conditions such as dermatopathic lymphadenopathy and reactive lymphoid hyperplasia. Although MCPyV causes subclinical infection in nearly all people and 22 % of healthy adults will harbor MCPyV in their buffy coats, circulating monocytes could serve as MCPyV reservoirs and cause disseminated skin lesions. Plasma sample from 12 patients with LCH-RO (-) (5 MS-LCH and 7 SS-LCH) and 5 non-LCH patients were analyzed by peptidomics. Mass spectrometry (MS) spectra were acquired and peptides exhibiting quantitative differences between MS-LCH and SS-LCH patients were targeted. One new candidate biomarker, m/z 3145 was selected and identified after obtaining a MS/MS fragmentation pattern using liquid chromatography-MS/MS. This peak was identified as a proteolytic fragment derived from inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4, [PDB: Q14624]). Peptidomics of LCH have revealed that the level of acute-phase ITIH4 distinguishes MS-LCH-RO (-) from SS

  5. [Recurrent pneumothorax in interstitial lung disease, anogenital and abdominal wall exanthema and secondary amenorrhea in a 20-year-old patient. Langerhans-cell histiocytosis].

    Science.gov (United States)

    Lockhart, I; Meuthen, I; Wolmerstett, M P

    2000-04-15

    A 20-year-old female patient was admitted to the hospital because of a pneumothorax. A secondary amenorrhea was coexisting. On the abdominal wall and in the anogenital area a maculopapular exanthema was visible. Chest X-ray and HR-CT showed an interstitial lung disease with high probability of histiocytosis X which was confirmed by biopsies of lung and skin tissue. The cause of amenorrhea was a histiocytic infiltration of the pituitary stalk. Conventional "consensus-treatment" for adults with vinblastine, prednisone and etoposide did not prevent relapsing bilateral pneumothoraces. Treatment was successful with the protocol as proposed by the international study for children. This treatment is characterized by higher dosage and combination with 6-mercaptopurine.

  6. Evolutionary dynamics of mammalian karyotypes

    Directory of Open Access Journals (Sweden)

    Carlo Alberto Redi

    2012-12-01

    Full Text Available This special volume of Cytogenetic and Genome Research (edited by Roscoe Stanyon, University of Florence and Alexander Graphodatsky, Siberian division of the Russian Academy of Sciences is dedicated to the fascinating long search of the forces behind the evolutionary dynamics of mammalian karyotypes, revealed after the hypotonic miracle of the 1950s....

  7. Steroids: A Timeless Fascination

    Indian Academy of Sciences (India)

    of vital importance to life such as sterols, bile acids, sex hormones ... 30. Lipoproteins are large assemblies of lipids in association with proteins. The two most important classes of lipoproteins are high density lipoprotein (HDL) and low density ... are important today as starting materials for the semi-synthesis of other me-.

  8. Fascinating Organic Transformations

    Indian Academy of Sciences (India)

    lne pairlnl/_. SERIES I ARTICLE sigma bonds in a previous article ~esonance, Vol. 1, No.1,. 1996). It may come as a surprise that water can form similar structures entirely through hydrogen bonds. The water mol- ecule has two donor sites (the ...

  9. MiR-145 inhibits metastasis by targeting fascin actin-bundling protein 1 in nasopharyngeal carcinoma.

    Directory of Open Access Journals (Sweden)

    Ying-Qin Li

    Full Text Available Based on our recent microarray analysis, we found that miR-145 was obviously downregulated in nasopharyngeal carcinoma (NPC tissues. However, little is known about its function and mechanism involving in NPC development and progression.Quantitative RT-PCR was used to detect miR-145 expression in NPC cell lines and clinical samples. Wound healing, Transwell migration and invasion, three-dimension spheroid invasion assays, and lung metastasis model were performed to test the migratory, invasive, and metastatic ability of NPC cells. Luciferase reporter assay, quantitative RT-PCR, and Western blotting were used to verify the target of miR-145.MiR-145 was obviously decreased in NPC cell lines and clinical samples (P<0.01. Ectopic overexpression of miR-145 significantly inhibited the migratory and invasive ability of SUNE-1 and CNE-2 cells. In addition, stably overexpressing of miR-145 in SUNE-1 cells could remarkably restrain the formation of metastatic nodes in the lungs of mice. Furthermore, fascin actin-bundling protein 1 (FSCN1 was verified as a target of miR-145, and silencing FSCN1 with small RNA interfering RNA could suppress NPC cell migration and invasion.Our findings demonstrated that miR-145 function as a tumor suppressor in NPC development and progression via targeting FSCN1, which could sever as a potential novel therapeutic target for patients with NPC.

  10. Reduced Abundance and Subverted Functions of Proteins in Prion-Like Diseases: Gained Functions Fascinate but Lost Functions Affect Aetiology

    Science.gov (United States)

    Nguyen-Phuoc, Kim; Leighton, Patricia L. A.

    2017-01-01

    Prions have served as pathfinders that reveal many aspects of proteostasis in neurons. The recent realization that several prominent neurodegenerative diseases spread via a prion-like mechanism illuminates new possibilities for diagnostics and therapeutics. Thus, key proteins in Alzheimer Disease and Amyotrophic lateral sclerosis (ALS), including amyloid-β precursor protein, Tau and superoxide dismutase 1 (SOD1), spread to adjacent cells in their misfolded aggregated forms and exhibit template-directed misfolding to induce further misfolding, disruptions to proteostasis and toxicity. Here we invert this comparison to ask what these prion-like diseases can teach us about the broad prion disease class, especially regarding the loss of these key proteins’ function(s) as they misfold and aggregate. We also consider whether functional amyloids might reveal a role for subverted protein function in neurodegenerative disease. Our synthesis identifies SOD1 as an exemplar of protein functions being lost during prion-like protein misfolding, because SOD1 is inherently unstable and loses function in its misfolded disease-associated form. This has under-appreciated parallels amongst the canonical prion diseases, wherein the normally folded prion protein, PrPC, is reduced in abundance in fatal familial insomnia patients and during the preclinical phase in animal models, apparently via proteostatic mechanisms. Thus while template-directed misfolding and infectious properties represent gain-of-function that fascinates proteostasis researchers and defines (is required for) the prion(-like) diseases, loss and subversion of the functions attributed to hallmark proteins in neurodegenerative disease needs to be integrated into design towards effective therapeutics. We propose experiments to uniquely test these ideas. PMID:29064456

  11. Histiocitose x (síndrome de hand-schuller-christian: relato de caso Histiocytosis X (Hand-Schuller-Christian disease: a case report

    Directory of Open Access Journals (Sweden)

    José Olimar Carneiro Filho

    2002-03-01

    Full Text Available Os autores relatam o caso de uma criança do sexo feminino, quatro anos de idade, que apresentava cefaléia, irritabilidade, otorréia e exoftalmia unilateral. No estudo tomográfico e na radiologia convencional encontraram-se grandes áreas líticas no crânio e na sua base. O restante do esqueleto não evidenciou anormalidades. O diagnóstico de histiocitose X (síndrome de Hand-Schuller-Christian foi confirmado pelo mielograma. Este estudo mostra achados radiológicos e citológicos, além de apresentar uma revisão da literatura sobre o caso.The authors report a case of a 4-year-old girl with headache, irritability, otorrhea, and unilateral exophthalmus. Computed tomography and plain films showed large lytic areas in the vault and base of the skull. No other bones were involved. The diagnosis of histiocytosis X (Hand-Schuller-Christian disease was confirmed by bone marrow biopsy. This paper presents the cytological and radiological findings of this patient as well as a review of the literature.

  12. Pulmonary Langerhans cell histiocytosis with cervical lymph node involvement, and coexistence with pulmonary tuberculosis and right pneumothorax: a case report and review of literature.

    Science.gov (United States)

    Gao, Limin; Li, Huifang; Li, Gandi; Liu, Weiping; Li, Jinnan; Zhang, Wenyan

    2015-01-01

    We report an uncommon 22-year-old male Pulmonary Langerhans Cell Histiocytosis (PLCH) case which co-existed with pulmonary tuberculosis (TB). Unlike the common PLCH cases, this PLCH case has cervical lymph node involvement and right pneumothorax. The diagnosis was established by the imaging of lung and the biopsies of the lung and left neck lymph node. Imaging of the chest showed characteristic small nodules and thin-walled cysts and right pneumothorax. The LCH cells in the lung and left neck lymph node were characterized by large convoluted nuclei with cerebriform indentations of the nuclear envelope and longitudinal grooves. The nuclei contained small eosinophilic nucleoli and moderate amount cytoplasm. Immunohistochemically, the histiocytoid cells were positive for Langerin, CD1a and S-100. Acid-fast bacilli were found in sputum and lung biopsy tissue. To the best of our knowledge, this is the first case of PLCH with cervical lymph node involvement, and coexisted with pulmonary tuberculosis, right pneumothorax. A contribution of this case and review three of the five cases of PLCH with extrapulmonary involvement to lymph nodes resolved spontaneously after smoking cessation constitute a novel addition that it is inappropriate to regard pulmonary/nodal LCH as multi-organ or disseminated disease, and the treatment methods are the same whether the PLCH patient with lymph node involvement or not.

  13. Predictor Variables of Developing Anterior Pituitary Deficiencies in a Group of Paediatric Patients with Central Diabetes Insipidus and Langerhans Cell Histiocytosis.

    Science.gov (United States)

    Vaiani, Elisa; Malossetti, Carmen; Vega, Lina Margarita; Zubizarreta, Pedro; Braier, Jorge; Belgorosky, Alicia

    2017-01-01

    Langerhans cell histiocytosis (LCH) is a rare histiocytic disorder of unknown etiopathogenesis. Central diabetes insipidus (CDI) is the most frequent endocrine manifestation and is a known risk factor for the development of further anterior pituitary hormone deficiencies (APD). However, not all CDI patients develop APD, as observed during prolonged periods of follow-up. To find predictors of developing APD in LCH children with CDI followed in our institution. We retrospectively analysed 44 patients over a median period (quartiles) of 12.3 years (8.79-14.24). Patients were subdivided into group 1 and group 2, according to absence or presence of APD, respectively. The main variables studied were: (1) chronological age (CA) at LCH diagnosis, (2) the primary site of LCH at diagnosis: low risk (LR) and multisystemic risk organs, and (3) the presence of reactivation. Multivariate Cox regression analysis showed that APD was positively associated with CA at LCH diagnosis [relative risk (RR) 1.14, p < 0.01], the LR clinical form (RR 8.6, p < 0.03), and negatively associated with the presence of reactivations (RR 0.3, p < 0.01). Patients with older CA at LCH diagnosis, LR clinical forms, and fewer reactivation episodes might represent a subgroup of paediatric LCH CDI patients with a higher risk of developing APD. © 2016 S. Karger AG, Basel.

  14. Langerhans cell histiocytosis: therapeutic strategy and outcome in a 30-year nationwide cohort of 1478 patients under 18 years of age.

    Science.gov (United States)

    Rigaud, Charlotte; Barkaoui, Mohamed A; Thomas, Caroline; Bertrand, Yves; Lambilliotte, Anne; Miron, Jean; Aladjidi, Nathalie; Plat, Geneviève; Jeziorski, Eric; Galambrun, Claire; Mansuy, Ludovic; Lutz, Patrick; Deville, Anne; Armari-Alla, Corinne; Reguerre, Yves; Fraitag, Sylvie; Coulomb, Aurore; Gandemer, Virginie; Leboulanger, Nicolas; Moshous, Despina; Hoang-Xuan, Khe; Tazi, Abdellatif; Heritier, Sébastien; Emile, Jean-François; Donadieu, Jean

    2016-09-01

    The French national cohort of children with Langerhans cell histiocytosis (LCH) has included 1478 patients since it was established in 1983. LCH therapeutic strategies substantially changed in 1998, so we have divided the cohort into two 15-year periods. Starting in 1998, therapy duration increased from 6 to 12 months, repeated induction therapy was performed in cases showing a poor response to the first induction with vinblastine and steroids, and refractory disease in a risk organ (RO+) was treated with cladribine and cytarabine. A total of 483 (33%) patients were enrolled before 1998, and 995 (67%) after 1998. Five-year survival was 96·6% (95% confidence interval: 95·4-97·5%) overall, improving from 92% pre-1998 to 99% post-1998 (P < 0·001 adjusted to disease extent). This change was supported by an increase in 5-year survival from 60% to 92% in the RO+ group. Survival was particularly associated with cladribine and cytarabine among refractory RO+ patients. Disease reactivation was slightly less frequent after 1998, due to better enrolment of single-system patients, extended therapy duration, and more efficient second-line therapy. The crude rates of endocrine and neurological sequelae (the most frequent sequelae) appeared to improve over time, but this difference was not observed when the analysis was stratified by disease extent. © 2016 John Wiley & Sons Ltd.

  15. Analysis of Fascin-1 in Relation to Gleason Risk Classification and Nuclear ETS-Related Gene Status of Human Prostate Carcinomas: An Immunohistochemical Study of Clinically Annotated Tumours From the Wales Cancer Bank.

    Science.gov (United States)

    Jefferies, Matthew T; Pope, Christopher S; Kynaston, Howard G; Clarke, Alan R; Martin, Richard M; Adams, Josephine C

    2017-01-01

    Although prostate-specific antigen (PSA) testing can identify early-stage prostate cancers, additional biomarkers are needed for risk stratification. In one study, high levels of the actin-bundling protein, fascin-1, were correlated with lethal-phase, hormone-refractory prostate cancer. Analyses of independent samples are needed to establish the value of fascin-1 as a possible biomarker. We examined fascin-1 by immunohistochemistry in tumour specimens from the Wales Cancer Bank in comparison with nuclear-located ETS-related gene (ERG), an emerging marker for aggressive prostate cancer. Fascin-1 was elevated in focal areas of a minority of tumours, yet fascin-1-positivity did not differentiate tumours of low-, intermediate-, or high-risk Gleason scores and did not correlate with PSA status or biochemical relapse after surgery. Stromal fascin-1 correlated with high Gleason score. Nuclear ERG was upregulated in tumours but not in stroma. The complexities of fascin-1 status indicate that fascin-1 is unlikely to provide a suitable biomarker for prediction of aggressive prostate cancers.

  16. Dynamics

    CERN Document Server

    Goodman, Lawrence E

    2001-01-01

    Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.

  17. Central diabetes insipidus as the inaugural manifestation of Langerhans cell histiocytosis: natural history and medical evaluation of 26 children and adolescents.

    Science.gov (United States)

    Marchand, Isis; Barkaoui, Mohamed Aziz; Garel, Catherine; Polak, Michel; Donadieu, Jean

    2011-09-01

    Isolated central diabetes insipidus (CDI) can be the first manifestation of Langerhans cell histiocytosis (LCH), creating diagnostic dilemmas such as dysgerminoma and other inflammatory lesions. In 2010, the French national LCH registry had enrolled 1236 LCH patients under 18 yr of age. Isolated CDI was the initial presentation of LCH in 26 patients. We reviewed their clinical and magnetic resonance imaging (MRI) features. Median age at the diagnosis of CDI was 9.6 yr (1.8-16.3), and median follow-up after CDI diagnosis was 9.9 yr (3.5-26.6). In addition to CDI, two patients had visual field defects, four had secondary amenorrhea, and 11 had anterior pituitary deficiency. Cerebral imaging (including computed tomography in two cases), performed in 22 patients within 3 months of CDI diagnosis, showed pituitary stalk thickening in 14 patients, which was moderate (3.0-7 mm) in nine cases and marked (>7 mm) in five cases. In eight cases, the lesion extended to the floor of the third ventricle. One child with LCH presented with a mild enlarged sellar content. During follow-up, 22 patients developed extrapituitary involvement, mainly of bone (n = 15), lung (n = 9), and skin (n = 9). Pituitary biopsy was performed in eight cases and was conclusive in six cases. Pituitary stalk thickening can be observed in LCH as well as lesions extending to the floor of the third ventricle. In all cases but one, the intrasellar content was not enlarged. Long-term follow-up with close attention to bone, skin, and lung disorders may lead to the diagnosis of LCH.

  18. Diagnósticos diferenciales de la histiocitosis a células de Langerhans The differential diagnostics of Langerhans cell histiocytosis

    Directory of Open Access Journals (Sweden)

    C. N. Chirino

    2007-06-01

    Full Text Available La histiocitosis a células de Langerhans (HCL debe diferenciarse de las siguientes entidades: eritema tóxico neonatorum (ETN, dermatitis seborreica (DS, foliculitis pustulosa eosinofílica (FPE, incontinencia pigmenti (IP, mastocitosis/urticaria pigmentosa (M/UP, acrodermatitis enteropática (ADE, síndrome de Wiskott-Aldrich (WAS, acropustulosis infantil (API. Además se deben considerar la enfermedad de Rosai- Dorfman (ERD, xantomas diseminados, melanosis pustulosa neonatal (MPN, candidiasis congénita, listeriosis neonatal, herpes simple perinatal y la varicela neonatal. Debido a que los métodos auxiliares de laboratorio no siempre están disponibles o los resultados laboratoriales algunas veces son extemporáneos, y puesto que el médico práctico a menudo necesita tomar decisiones precozmente, es que la epidemiología resulta útil, pues brinda el marco adecuado para ordenar y jerarquizar las sospechas diagnósticas frente a un caso concreto, con un paciente determinado, en un momento específico.The differential diagnostics of Langerhans cell histiocytosis should include the following disorders: erythema toxicum neonatorum, seborrheic dermatitis, eosinophilic pustular folliculitis, incontinentia pigmenti, mastocytosis / urticaria pigmentosa, acrodermatitis enteropathica, Wiskott-Aldrich syndrome, infantile acropustulosis, Rosai- Dorfman disease, xanthoma disseminatum, neonatal pustular melanosis, congenital candidiasis, perinatal listeriosis, perinatal herpes simplex, neonatal varicella. Since the auxiliary methods of lab are not always available, or lab results are sometimes extemporaneous, the physicians often needs to make quick decisions. The epidemiology is useful because it offers the appropriate mark to prioritize the diagnostic in specific cases

  19. Clinical course of the bony lesion of single-system single-site Langerhans cell histiocytosis - Is appropriate follow-up sufficient treatment?

    Science.gov (United States)

    Sasaki, Hiromi; Nagano, Satoshi; Shimada, Hirofumi; Nakamura, Shunsuke; Setoguchi, Takao; Komiya, Setsuro

    2018-01-01

    Langerhans cell histiocytosis (LCH) is categorized into three types, which include single-system single-site (SS-s), single-system multiple-site (SS-m) and multisystem (MS). The most commonly affected site in LCH is bone, and the bony lesion of SS-s LCH has a good prognosis. The bony lesion of SS-s LCH has been thought to regress spontaneously. Although treatments such as curettage, direct injection of corticosteroids, and chemotherapy have been performed, regular follow-up is the first line of treatment for the bony lesion of SS-s LCH. For preventing orthopedic sequelae, strict and appropriate follow-up should be performed, but the appropriate period and method of follow-up has not yet been established. In the present study, we retrospectively analyzed a series of 7 cases of patients with SS-s LCH with a bony lesion treated in the Department of Orthopedic Surgery at Kagoshima University Hospital (Kagoshima, Japan) from 2006 to 2015. The bony lesion regressed spontaneously in all patients. Factors such as location, size, preoperative C-reactive protein (CRP) value, standardized uptake (SUV) value of positron emission tomography (PET), age, sex and direct steroid injection were not related to the clinical course. Temporary expansion of the lesion occurred in 3 patients and a temporary worsening of pain occurred in 1 patient during the follow-up period. These events occurred within 6 weeks after biopsy. Careful follow-up and the use of an appropriate orthosis can lead to a good clinical course for the bony lesion of SS-s LCH. Future research should seek to determine the appropriate follow-up period. Copyright © 2017 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

  20. Histiocitose das células de Langerhans: experiência de 16 anos Langerhans cell histiocytosis: a 16-year experience

    Directory of Open Access Journals (Sweden)

    Márcia Kanadani Campos

    2007-02-01

    Full Text Available OBJETIVOS: Descrever a apresentação clínica da histiocitose das células de Langerhans e comparar sua evolução de acordo com a idade, estadiamento e resposta ao tratamento. MÉTODOS: Análise retrospectiva dos dados referentes a 33 crianças com histiocitose das células de Langerhans acompanhadas no Hospital das Clínicas da Universidade Federal de Minas Gerais no período de 1988 a 2004. RESULTADOS: A idade ao diagnóstico variou de 2 meses a 16 anos (mediana: 2,5 anos. Dezessete crianças eram do sexo masculino. O tempo de seguimento variou de 21 dias a 16,2 anos (mediana: 3,4 anos. As manifestações clínicas mais comuns ao diagnóstico foram lesões osteolíticas, linfadenomegalia e lesões cutâneas. A sobrevida global para todo o grupo foi de 86,1% aos 16 anos (IC95% 66,6-94,6. Os óbitos ocorreram em pacientes com doença multissistêmica e disfunção orgânica ao diagnóstico. Os pacientes que apresentaram resposta "melhor" à sexta semana de tratamento apresentaram uma probabilidade estimada de sobrevida global significativamente maior em relação aos que apresentaram progressão da doença. A sobrevida global foi significativamente maior para os pacientes com doença em um único sistema. A probabilidade de sobrevida livre de eventos para todo o grupo foi de 30,9% aos 16 anos (IC95% 15,6-47,5, sendo significativamente maior para os portadores de doença em um único sistema. A idade não se associou com a sobrevida livre de eventos. A seqüela mais comum foi o diabetes insipidus. Não foram observados casos de neoplasias secundárias. CONCLUSÃO: A histiocitose das células de Langerhans apresenta uma grande variedade de manifestações clínicas, com alta taxa de recidivas e baixa taxa de mortalidade.OBJECTIVES: To describe the clinical course of Langerhans cell histiocytosis and to compare its outcome according to age, staging of the disease and treatment response. METHODS: Retrospective analysis of data on 33 children with

  1. Dynamic Responsive Systems for Catalytic Function

    NARCIS (Netherlands)

    Vlatkovic, Matea; Collins, Beatrice S. L.; Feringa, Ben L.

    2016-01-01

    Responsive systems have recently gained much interest in the scientific community in attempts to mimic dynamic functions in biological systems. One of the fascinating potential applications of responsive systems lies in catalysis. Inspired by nature, novel responsive catalytic systems have been

  2. Crystal-storing histiocytosis due to massive accumulation of charcot-leyden crystals: a unique association producing colonic polyposis in a 78-year-old woman with eosinophilic colitis.

    Science.gov (United States)

    Lewis, Jason T; Candelora, Joseph N; Hogan, Reed B; Briggs, Frank R; Abraham, Susan C

    2007-03-01

    Crystal-storing histiocytosis is a rare diagnosis that to date has only been associated with 2 conditions: intracytoplasmic accumulation of crystallized immunoglobulins in patients with lymphoproliferative disorders or plasma cell dyscrasias, and histiocytic accumulations of phagocytosed clofazimine, a drug used to treat lepromatous leprosy. We describe a 78-year-old woman with a past medical history of dermatologic mastocytosis and peripheral eosinophilia who presented with diarrhea and weight loss, and was found at colonoscopy to have polyposis limited to the right and transverse colon. She eventually underwent subtotal colectomy to remove the segment of polyposis. At gross examination, the colonic mucosa contained numerous polyps ranging from 1 to 7 mm which on histologic evaluation proved to represent mucosal and submucosal collections of histiocytes whose cytoplasm was distended by numerous brightly eosinophilic crystals. An intense eosinophilic infiltrate surrounded the histiocyte collections and also mildly involved the intervening colonic mucosa and superficial submucosa. Electron microscopy confirmed the presence of intracytoplasmic material identical to Charcot-Leyden crystals within histiocytes, representing the breakdown products of degranulated eosinophils. This is the first reported case of crystal-storing histiocytosis produced by massive accumulation of Charcot-Leyden crystals in eosinophilic colitis.

  3. Collective dynamics of active cytoskeletal networks

    CERN Document Server

    Köhler, Simone; Bausch, Andreas R

    2011-01-01

    Self organization mechanisms are essential for the cytoskeleton to adapt to the requirements of living cells. They rely on the intricate interplay of cytoskeletal filaments, crosslinking proteins and molecular motors. Here we present an in vitro minimal model system consisting of actin filaments, fascin and myosin-II filaments exhibiting pulsative collective long range dynamics. The reorganizations in the highly dynamic steady state of the active gel are characterized by alternating periods of runs and stalls resulting in a superdiffusive dynamics of the network's constituents. They are dominated by the complex competition of crosslinking molecules and motor filaments in the network: Collective dynamics are only observed if the relative strength of the binding of myosin-II filaments to the actin network allows exerting high enough forces to unbind actin/fascin crosslinks. The feedback between structure formation and dynamics can be resolved by combining these experiments with phenomenological simulations base...

  4. Holomorphic Dynamical Systems

    CERN Document Server

    Guenot, Jacques; Patrizio, Giorgio

    2010-01-01

    The theory of holomorphic dynamical systems is a subject of increasing interest in mathematics, both for its challenging problems and for its connections with other branches of pure and applied mathematics. This volume collects the Lectures held at the 2008 CIME session on "Holomorphic Dynamical Systems" held in Cetraro, Italy. This CIME Course focused on a number of important topics in the study of discrete and continuous dynamical systems, including both local and global aspects, providing a fascinating introduction to many key problems in current research. The contributions provide an ample description of the phenomena occurring in central themes of holomorphic dynamics such as automorphisms and meromorphic self-maps of projective spaces, of entire maps on complex spaces and holomorphic foliations in surfaces and higher dimensional manifolds, elaborating on the different techniques used and familiarizing readers with the latest findings on current research topics.

  5. Relativistic Dynamics of Graphene

    Science.gov (United States)

    Semenoff, Gordon

    2011-10-01

    Graphene is a one-atom thick layer of carbon atoms where electrons obey an emergent Dirac equation. Only seven years after it first became available in the laboratory, graphene has captured the attention of a wide spectrum of scientists: from particle physicists interested in using graphene's emergent relativistic dynamics to study quantum field theory phenomena to condensed matter physicists fascinated by its unusual electronic propertied and technologists searching for materials for the nest generation of electronic devices. This presentation will review the basics of graphene and some questions, such as the possibility of chiral symmetry breaking, which have overlap with similar ones in strong interaction particle physics.

  6. Histiocitose de células de Langerhans em margem anal: relato de caso e revisão da literatura Perianal Langerhans cell histiocytosis: case report and literature review

    Directory of Open Access Journals (Sweden)

    Jaime Coelho Carlos Magno

    2007-03-01

    Full Text Available Um caso incomum de histiocitose de células de Langerhans comprometendo margem anal em adulto de cor branca com 34 anos de idade é descrito. Durante dezenove meses o paciente apresentou ulceração extensa em margem anal, dolorosa, com sangramento, evoluindo para incontinência fecal. A hipótese diagnóstica inicial ficou entre doença de Crohn, sífilis, tuberculose, pioderma gangrenoso e donovanose. O diagnóstico histopatológico, após a terceira biópsia, foi sugestivo de histiocitose X, diagnóstico esse confirmado pelo estudo imunoistoquímico positivo para CD1a e proteína S100. O paciente foi tratado com seis sessões de injeção intralesional de triancinolona e talidomida por via oral, durante três meses, evoluindo com remissão completa da lesão anal e recuperação da continência esfincteriana.A rare case of Langerhans cell histiocytosis with perianal involvement in a 34 year old white man is presented. During nineteen months this patient had a complaint of anal pain with bleeding, due to a large perianal ulcer. The initial diagnosis was Crohn's disease, anal tuberculosis, syphilis, pyoderma gangrenosum or donovanosis. After the third biopsy, the surgical specimens showed microscopic changes suggestives of Langerhans cell histiocytosis. The imunohistochemical study was positive to S100 protein and CD1a. The patient was treated with six doses of intralesional triancinolona and oral thalidomide for three months. Treatment was well tolerated and complete resolutions of peri-anal ulcer occurred.

  7. Histiocitosis de células de Langerhans localizada en hueso malar: Presentación de un caso Localized langerhans cell histiocytosis of the zygomatic bone: A case report

    Directory of Open Access Journals (Sweden)

    María Loreto Castellón Zirpel

    2011-09-01

    Full Text Available La histiocitosis de células de Langerhans localizada (HCLL, conocida como granuloma eosinófilo, representa entre el 50 y el 60% de todos los casos de histiocitosis de células de Langerhans. El tratamiento clásico para la HCLL ha sido el curetaje o la resección de las lesiones óseas. Hay publicaciones de casos tratados con inyección intralesional de corticosteroides, combinado con curetaje. Se presenta un caso clínico de un paciente de tres años de edad con diagnóstico de HCLL que compromete en su extensión el hueso malar, tratado con infiltraciones de corticosteroides y posterior curetaje de la lesión. A un año de realizado el tratamiento, el paciente se encuentra asintomático y con una regeneración ósea del hueso malar, evidenciable en la tomografía axial computarizada.Localized Langerhans cell histiocytosis (LLCH, also known as eosinophilic granuloma, represents 50 to 60% of all cases of Langerhans cell histiocytosis. The standard treatment for LLCH has been lesion curettage or resection. Cases treated with intralesional corticosteroid injections combined with curettage have been described. We report the case of a three-year-old patient diagnosed of LLCH with extensive zygomatic bone involvement, who was treated with corticosteroid infiltrations and subsequent curettage of the lesion. One year after treatment, the patient is asymptomatic with zygomatic reossification evidenced on computed tomography.

  8. Fascinating physics. An illustrated expedition from the universe until the world of the elementary particles; Faszinierende Physik. Ein bebildeter Streifzug vom Universum bis in die Welt der Elementarteilchen

    Energy Technology Data Exchange (ETDEWEB)

    Bahr, Benjamin [Albert-Einstein-Institut (Max-Planck Institut fuer Gravitationsphysik), Golm (Germany); Riebe, Kristin [Potsdam Univ. (Germany). Leibniz-Institut fuer Astrophysik; Resag, Joerg

    2013-07-01

    ''Fascinating physics'' is a picturesque expedition through 140 themes of classical and modern physics. On each one double-page to the reader is thereby offered a compact access in each one theme: From the aurora until the black hole, from the particle accelerator until the GPS system, from the curved space-time until the supersymmetry, from the oscillating dipole until Foucault's pendulum - a large variety of themes is taken up and carefully explained. Thereby the special strength of the book lies in the clear language and the explanations get along mostly without formulas - accompanied by breathtaking pictures, which lead the beauty of our world in front of the eyes.

  9. The fascinating early history of optics! Archaeological optics 2009: our knowledge of the early history of lenses, mirrors, and artificial eyes!

    Science.gov (United States)

    Enoch, Jay M.

    2009-08-01

    The early history of optics and vision science (older term: physiological optics) is indeed fascinating. The earliest known true lenses have been found in "eyes" of Egyptian statues which contain superb, complex, and well-polished eye-lens units. The oldest ones known are dated circa 2575 BCE = BC, Dynasty IV, Old Kingdom. These eye-lens units induce a fascinating and powerful visual illusion, but they are just too good to have been the first lenses, or even the first lenses of this design! So saying, no earlier dateable lenses have been found in Egypt or elsewhere. Recently, at the Boston Museum of Fine Arts, the writer noted a previously undetected lens in this series (a first in the Western Hemisphere). Oddly, dateable simpler magnifying lenses and burning glasses seem to have appeared later in time (?)! Manufactured mirrors are quite a bit older, dating from circa 6000 BCE in atal Hyk, located in south-central modern-day Turkey. Using these ancient mirrors, the image quality obtained is remarkable! Recently discovered ancient artificial eyes, located, in situ, in exhumed corpses, have been dated circa 3000 BCE (one discovered in Iran) 5000 BCE (one found in Spain). On the 3000 BCE artificial eye, there are drawn light rays (the writer believes these to be the oldest known depiction of light rays!) spreading out from (or passing into) the iris/ pupil border! Added interesting aspects associated with the early development of light-rays are considered. Thus, early optics can be readily traced back to the Neolithic era (the new stone age), and in some cases before that time period. We have deep roots indeed!

  10. Sinus Histiocytosis with Massive Lymphadenopathy

    African Journals Online (AJOL)

    1974-03-09

    Mar 9, 1974 ... REPORT OF TWO ADDITIONAL CASES WITH ULTRASTRUCTURAL. OBSERVATIONS c. C. SUNCLAIR~NUTH. L. B. KAHN. C. J. UYS. SUMMARY. Two cases of a recently described entity, 'sinus histio- cytosis with massive lymphadenopathy,' occurring in Black males, are reported. Prominent cervical ...

  11. Fascinating Organic Molecules from Nature

    Indian Academy of Sciences (India)

    Keywords. Indigo; indican; isatin; indoxyl; thioindigo and Tyrian purple. Author Affiliations. N R Krishnaswamy1 C N Sundaresan2. No.12, 9th Main Road Banashankari 2nd Stage Bangalore 560 070, India. Department of Chemistry Sri Sathya Sai Institute of Higher Learning Brindavan Campus Bangalore 560 067, India.

  12. Fascinating World of Shock Waves

    Indian Academy of Sciences (India)

    Srimath

    The dissipation of mechanical, nuclear, chemi- cal, and electrical energy in a limited space will usually result in ... the vehicle and the shock wave usually referred to as the shock layer will be a region of high .... successfully visualized a shock wave during an electric spark discharge process using stroboscopic method.

  13. Fascinating Organic Molecules from Nature

    Indian Academy of Sciences (India)

    IAS Admin

    SERIES | ARTICLE. This salicylic acid derivative (it gives a violet colour with alco- holic ferric chloride) gives a dihydro derivative (9) on catalytic hydrogenation. Both (8) and (9) on prolonged hydrogenation yield the optically inactive tatrahydrotubaic aciod (10). The latter on decarboxylation, by heating to its melting point, ...

  14. Graphene and its fascinating attributes

    CERN Document Server

    Enoki, Toshiaki; Rao, C N R

    2011-01-01

    Graphene, a single sheet of graphite, has an unconventional electronic structure that can be described in terms of massless Dirac Fermions. This interesting electronic feature is not only an important fundamental issue in condensed matter physics but also

  15. Fascinating Organic Molecules from Nature

    Indian Academy of Sciences (India)

    IAS Admin

    The sense of smell plays a vital role in the animal kingdom. The olfactory nerves situated in the nasal passages of human beings are sensitive enough to detect, for example, one three-hundred- millionth part of a grain of musk. The olfactory organs of several animals are even more sensitive. Some moths are known to be.

  16. Fascinating Organic Molecules from Nature

    Indian Academy of Sciences (India)

    IAS Admin

    bases which was further methylated and subjected to a second. Hofmann degradation. This resulted in the formation of trimethy- lamine and a nitrogen-free compound (4). On oxidative degrada- tion, (4) gave a tricarboxylic acid (5) which on fusion with alkali yielded 4-hydroxybenzoic acid (6). After a one-stage Hofmann.

  17. Fascinating Organic Molecules from Nature

    Indian Academy of Sciences (India)

    IAS Admin

    in Tamil) is used for making the percussion instrument, Thavil, which is played in conjunction with the wind instrument, nadaswaram (similar to the shehnai and the clarinet). The pig- ments of the wood have been characterized as quinonoid com- pounds derived from a cadalene type sesquiterpene structure. In New Zealand ...

  18. [Floral essences, a fascinating world].

    Science.gov (United States)

    Llonch, María

    2005-05-01

    Floral essences were discovered in the decade of the thirties by the English doctor, bacteriologist and homeopath Dr. Edward Bach. He described 38 remedies elaborated with flowers and shoots; each one correspondeds to an emotional pattern or a typical personality. Furthermore, he describes a remedy developed for emergency situations.

  19. A toddler with hair fascination.

    Science.gov (United States)

    Kao, Patricia; Needlman, Robert D; Stein, Martin T

    2010-04-01

    Joseph is a 24-months old boy referred by his pediatrician because of an "obsession" with pulling and eating hair. When Joseph was 14 months old, he enjoyed touching and twirling his mother's long hair. She observed that it seemed to provide comfort to him. At 18 months, he initiated pulling out and eating his own hair, twirling his mother's hair around his thumb and then sucking on it. Currently, he searches the carpet or a hard floor and looks for hair to eat. The identical behavior is observed at daycare. Joseph's teacher commented, "He pulled hair from a girl who has the longest hair of all the children. We try to distract him from this habit, but he is not distracted for long." Less frequently, Joseph has also eaten sand, chalk, and crayons at daycare. Joseph's mother describes him as a "happy and outgoing" child who interacts with his peers and has a best friend at the daycare. There have not been recent changes or stressful events in his life. Joseph separates from his mother with ease and he sleeps comfortably through the night in his own bed. There have been no episodes of nausea, vomiting, abdominal pain, or constipation. Strands of hair are occasionally seen in the stool. Prenatal and perinatal history was unremarkable. Joseph was breast-fed for 11 months, described as an "easy" baby, achieved motor, social, and language developmental milestones at the usual time, and has been in excellent health. He lives with his mother and maternal grandparents; the biological father has never been involved in his care. At 20 months, Joseph's pediatrician suggested cutting his hair. After several haircuts, Joseph stopped pulling his own hair. However, he continued to search the floor for hair. Hemoglobin and a blood lead level were normal. Joseph appeared pleasant and friendly with normal growth parameters and facial features. He was sitting comfortably on his mother's lap, sucking on his thumb. Social interactions with his mother were appropriate and reciprocal. He warmed up quickly to the examiner and engaged in play. He spoke in two to three word sentences and responded to questions with a speech pattern that was 50% intelligible. Physical and developmental examinations were normal. At the end of the examination, Joseph searched his mother's purse and located a piece of hair. He twirled the hair around his thumb and sucked on it. Initially, he refused to remove his thumb from his mouth. With gentle persuasion, he eventually removed his thumb and agreed to throw the hair in the trash. He did not appear distressed.

  20. Frederik Ruysch's Fascination With Urolithiasis

    Science.gov (United States)

    Moran, Michael E.; Ruzhansky, Katherine

    2008-09-01

    Frederik Ruysch was born on March 23, 1638, in The Hague, and studied at the University of Leiden, where he graduated in 1664. He married a daughter of a famous architect and became a praelector of the Amsterdam surgeon's guild in 1665. In 1666, his rise continued, as he became elected as the Professor of the Anthenaeum Illustre. In 1668, Ruysch became the chief instructor to the midwives and by 1679 was the forensics advisor to Amsterdam's courts. His anatomical knowledge was second to none, and he gained worldwide notoriety for his discovery of the valves in lymphatics and the vomeronasal organ. Ruysch was keenly interested in dissection and anatomy, and developed his own methods for preservation of specimens. His secret was called liquor balsamicum. Over 300 years ago, Ruysch developed all of his talents to the point of creating a menagerie, of sorts, out of his specimens. The popularity of his rather morbid exhibits attracted such dignitaries as Peter The Great in 1697. Ruysch had several children from his marriage, and his daughter Rachel helped him illustrate many of his collections. Frederik Ruysch became an intriguing historical figure, worthy of some attention at kidney stone meetings, precisely because he chose these concretions to serve as one of the "finishing elements" in several of his collections. The purpose of this presentation is to present to a knowledgeable stone group, the artistic license of one of the first entrepreneurial surgeons and anatomists of the 17th century. Ruysch was a skilled surgeon, obstetrician, and anatomist, keenly interested in the science of anatomy, especially infant and fetal anatomy. In addition, he exhibited his fine collection of urinary stones in a rather unique way, in his "anatomical pieces."

  1. Fascinating Organic Molecules from Nature

    Indian Academy of Sciences (India)

    IAS Admin

    flycatchers and skylarks. The colour seen in a passerine feather is the result of a combination of pigmentation and special structural features. Shades of white and blue are primarily due to refraction. Box 1. Functions of Bird Feathers. The most characteristic feature of a bird is its plumage. A feather is not just an appendage.

  2. Fascinating Organic Molecules from Nature

    Indian Academy of Sciences (India)

    IAS Admin

    Learning. He has the uncanny ability to present the chemistry of natural products logically and with feeling. (Right) C N Sundaresan is currently an Associate. Professor in the Depart- ... scientific journals but also in books and even on the celluloid! Recent studies show that ..... In their natural environment, the snails use this ...

  3. Histiocitose de células de Langerhans com acometimento vulvar e com resposta terapêutica à talidomida: relato de caso Langerhans cells histiocytosis with vulvar involvement and responding to thalidomide therapy: case report

    Directory of Open Access Journals (Sweden)

    Lana Bezerra Fernandes

    2011-08-01

    Full Text Available A histiocitose de células de Langerhans é representante de um raro grupo de síndromes histiocitárias, sendo caracterizada pela proliferação das células de Langerhans. Suas manifestações variam de lesão solitária a envolvimento multissistêmico, sendo o acometimento vulvar incomum. Segue-se o relato de caso refratário da doença limitada à pele, em mulher de 57 anos. A paciente apresentava história de pápulas eritematosas ulceradas em couro cabeludo, face, vulva, tronco e axila há seis anos. O diagnóstico da doença é difícil, sendo confirmado neste caso através de estudo imuno-histoquímico e se obteve resposta terapêutica e eficaz, com a administração de talidomidaLangerhans cell histiocytosis is a member of a group of rare histiocytic syndromes and is characterized for the proliferation of histiocytes called Langerhans'cells. Its manifestations vary from a solitary injury to systemic involvement, and vulvar lesions are uncommon. We describe a refractory case of cutaneous limited disease in a 57-year-old woman. She presented with a 6-year history of an erythematous papular eruption of the scalp, face, vulva, trunk and axillae. The diagnosis is difficult and in this case it was confirmed through immunohistochemical study and clinical improvement was achieved with thalidomide

  4. Transitional Dynamics Towards Sustainability: Reconsidering the EKC Hypothesis

    OpenAIRE

    Bella, Giovanni

    2006-01-01

    The Environmental Kuznets Curve (EKC) hypothesis is one of the most debated economic issues. Despite its fascinating appeal for any policy maker, neither theoretical nor certain empirical evidence has been found to clean up all doubt. The aim of this paper is to present an economy where environmental quality and polluting emissions do enter the maximisation problem, and provide a transitional dynamics analysis to pursue a new different version of the EKC, depending on the level of development...

  5. Hallazgos en el macizo facial y la base del cráneo de pacientes pediátricos con histiocitosis de células de Langerhans Craniofacial and skull base findings in Langerhans cell histiocytosis in pediatric patients

    Directory of Open Access Journals (Sweden)

    Daniel Forlino

    2013-03-01

    Full Text Available La histiocitosis de células de Langerhans (HCL es una entidad poco frecuente, con una incidencia anual de 2,6 a 5,4 por millón de niños en la población general. Tiene manifestaciones óseas (lesiones osteolíticas solitarias o múltiples en huesos planos, largos e irregulares o multisistémicas. Se describen los hallazgos imagenológicos de una serie retrospectiva de 17 pacientes pediátricos, de 1 a 12 años de edad, con histiocitosis de células de Langerhans en el macizo facial y la base del cráneo. Las manifestaciones incluyeron lesiones osteolíticas y masa de partes blandas, que ocupaban las cavidades adyacentes, como la órbita, los senos paranasales, la caja timpánica y la mastoides. En el maxilar inferior puede provocar reabsorción del reborde alveolar con apariencia de dientes flotantes. La complejidad anatómica del área de estudio requiere su valoración mediante tomografía computada (TC y resonancia magnética (RM con contraste. La histiocitosis de células de Langerhans debe considerarse dentro de los diagnósticos diferenciales de las lesiones del macizo facial y la base del cráneo, especialmente en pacientes pediátricos.Langerhans cell histiocytosis (CLH is an uncommon entity, of unknown etiology, with an incidence of 2.6 at 5.4 per 1,000,000 children/year in the general population. It may have bone manifestations (solitary or multiple osteolytic lesions in flat, long and irregular bones or multiorgan manifestations. We report the radiological findings in retrospective series of 17 pediatric patients aged 1 to 12 years old, with CLH in craniofacial and skull base. Radiological findings included osteolytic and soft tissue lesions occupying the orbit, sinuses, tympanic cavity and mastoid. In the mandible, reabsorption of the alveolar ridge with the appearance of floating teeth was observed. The anatomical complexity of the area studied required evaluation by CT and MRI with contrast. LCH disease should be considered in

  6. Protein dynamics and enzyme catalysis: insights from simulations.

    Science.gov (United States)

    McGeagh, John D; Ranaghan, Kara E; Mulholland, Adrian J

    2011-08-01

    The role of protein dynamics in enzyme catalysis is one of the most active and controversial areas in enzymology today. Some researchers claim that protein dynamics are at the heart of enzyme catalytic efficiency, while others state that dynamics make no significant contribution to catalysis. What is the biochemist - or student - to make of the ferocious arguments in this area? Protein dynamics are complex and fascinating, as molecular dynamics simulations and experiments have shown. The essential question is: do these complex motions have functional significance? In particular, how do they affect or relate to chemical reactions within enzymes, and how are chemical and conformational changes coupled together? Biomolecular simulations can analyse enzyme reactions and dynamics in atomic detail, beyond that achievable in experiments: accurate atomistic modelling has an essential part to play in clarifying these issues. This article is part of a Special Issue entitled: Protein Dynamics: Experimental and Computational Approaches. Copyright © 2010 Elsevier B.V. All rights reserved.

  7. Evolutionary dynamics of complex communications networks

    CERN Document Server

    Karyotis, Vasileios; Papavassiliou, Symeon

    2013-01-01

    Until recently, most network design techniques employed a bottom-up approach with lower protocol layer mechanisms affecting the development of higher ones. This approach, however, has not yielded fascinating results in the case of wireless distributed networks. Addressing the emerging aspects of modern network analysis and design, Evolutionary Dynamics of Complex Communications Networks introduces and develops a top-bottom approach where elements of the higher layer can be exploited in modifying the lowest physical topology-closing the network design loop in an evolutionary fashion similar to

  8. Quantitative real-time RT-PCR validation of differential mRNA expression of SPARC, FADD, Fascin, COL7A1, CK4, TGM3, ECM1, PPL and EVPL in esophageal squamous cell carcinoma

    Directory of Open Access Journals (Sweden)

    Wang Yuan

    2006-02-01

    Full Text Available Abstract Background Esophageal squamous cell carcinoma (ESCC is one of the most malignant tumors and typically presents at an advanced and rapidly fatal stage. To better understand the role of genetics in the etiology and prevention of ESCC and to identify potential susceptibility genes as well as early detection markers, we previously compared tumor and matched normal tissues from ESCC patients from a high-risk area of China using cDNA expression microarrays and identified 41 differentially-expressed genes (13 over-expressed and 28 under-expressed. Methods In the current study, we validated and quantitated differential mRNA expression in a sample of nine of these 41 genes, including four that were over-expressed (SPARC, FADD, Fascin, COL7A1, and five that were under-expressed (CK4, TGM3, ECM1, PPL, EVPL, in 75 new ESCC patients using quantitative Real-time RT-PCR and the 2-ΔΔCT method to examine both tumor and matched normal tissue. In addition, we examined expression patterns for these genes by selected demographic and clinical characteristics. Results Four previously over-expressed (tumor ≥2-fold normal genes were all increased in the majority of new ESCC patients: SPARC was increased in 71% of patients, Fascin in 70%, FADD in 63%, and COL7A1 in 57%. Five previously under-expressed (tumor ≤0.5-fold normal genes similarly showed decreased mRNA expression in two-thirds or more of patients: CK4 was decreased in 83% of patients, TGM3 in 77%, ECM1 in 73%, and PPL and EVPL in 67% each. In subset analyses, associations with age (for COL7A1, family history (for PPL and ECM1, and alcohol use (for SPARC and Fascin were also noted. Conclusion These data indicate that these nine genes have consistent differential mRNA expression, validating results of our previous cDNA array results, and affirming their potential role in the early detection of ESCC.

  9. An exploration of dynamical systems and chaos

    CERN Document Server

    Argyris, John H; Haase, Maria; Friedrich, Rudolf

    2015-01-01

    This book is conceived as a comprehensive and detailed text-book on non-linear dynamical systems with particular emphasis on the exploration of chaotic phenomena. The self-contained introductory presentation is addressed both to those who wish to study the physics of chaotic systems and non-linear dynamics intensively as well as those who are curious to learn more about the fascinating world of chaotic phenomena. Basic concepts like Poincaré section, iterated mappings, Hamiltonian chaos and KAM theory, strange attractors, fractal dimensions, Lyapunov exponents, bifurcation theory, self-similarity and renormalisation and transitions to chaos are thoroughly explained. To facilitate comprehension, mathematical concepts and tools are introduced in short sub-sections. The text is supported by numerous computer experiments and a multitude of graphical illustrations and colour plates emphasising the geometrical and topological characteristics of the underlying dynamics. This volume is a completely revised and enlar...

  10. Contribution to the radiological study of the eosinophilic granuloma of the mandible (Unifocal granuloma due to Langherans' cell histiocytosis); Contributo allo studio radiologico del granuloma eosinofilo della mandibola (granuloma unifocale da istiocitosi delle cellule di Lagherhans)

    Energy Technology Data Exchange (ETDEWEB)

    Chigi, Gino; Pastremoli, Alessandro; Pisi, Paolo; Pastremoli, Alfredo [Bologna Univ., Bologna (Italy). Dipartimento di scienze odontomastologiche; Bianchi, Giuseppe [Istituti Ortopedici Rizzoli, Bologna (Italy)

    2005-04-01

    Purpose: The radiological diagnosis of osteolytic lesions of the mandible still constitutes a challenge in some pathological conditions in which the clinical data and the case history are relatively uniform and the radiological picture is lacking in any characteristics. Materials and methods: We reviewed the conventional radiograms of six cases of Langherans' cell histiocytosis (LCH) of the mandible examined over the last ten years. The X-ray examinations were performed in the lateral-oblique projection to allow a view of the horizontal portion of the mandible almost completely free of overlapping images of other bone structures. Results: We identified a series of radiological patterns for these reticulo-endotheliopathies capable of causing granuloma formed by polinuclear eosinophils, plasma cells, lymphocytes, and large mononuclear macrophages with granulopexic and phagocytic activity that proliferate in the bone tissue and can be identified as the Langherans' cells of skin, mucosa, periodontal cavities and bone marrow. The granulomatous tissue penetrates the affected organ elements and, in its spread, it compresses, atrophies, and destroyed the damaged tissue, replacing it. The alterations produced by Langherans' cell histiocytic granuloma are most common in the skeletal system affecting, in order of frequency, the skull, the long bones of the limbs, the foot, the ribs and the spine. The oral mucosa is rarely involved. Conclusions: The radiological investigation of unifocal Langherans' cell histiocytic granuloma of the mandible is essential in the study of perimandibular swelling, although diagnosis is based on biopsy alone. In addition to digital or conventional radiography, other useful examinations are bone scintigraphy, Colour Doppler US, MR and CT, which enables a correct localisation necessary for planning the biopsy and treatment. [Italian] Scopo: La diagnosi radiologica delle lesioni osteolitiche della mandibola costituisce un problema

  11. MRI features of neurodegenerative Langerhans cell histiocytosis

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Duverneuil, N.; Guillevin, R.; Chiras, J. [GH Pitie-Salpetriere, 47 Bd de l' Hopital, Department of Neuroradiology, Paris (France); Idbaih, A.; Hoang-Xuan, K. [GH Pitie-Salpetriere, 47 Bd de l' Hopital, Department of Neurology, Paris (France); Donadieu, J. [GH Trousseau, Department of Hematology/Oncology Pediatrics, Paris (France); Genereau, T. [Groupe d' etude des Histiocytoses langerhansiennes, Nantes (France)

    2006-09-15

    CNS complications of LCH include ''space occupying'' lesions corresponding to histiocytic granulomas and ''neurodegenerative'' presentation (ND-LCH) characterized by a progressive cerebellar ataxia. Studies analyzing specifically the MRI presentation of ND-LCH are scarce. We present here the MRIs of 13 patients registered as isolated ND-LCH. Posterior fossa was involved in 12 patients (92%), showing a symmetrical T2 hyperintensity of the cerebellar white matter areas in seven cases with a circumscribed T1 hyperintensity of the dentate nuclei in five cases, definite hyperintense T2 areas in the adjacent pontine tegmentum white matter in nine cases associated with a hyperintensity of the pontine pyramidal tracts in four cases. A cerebellar atrophy was noted in eight cases. The supratentorial region was involved in 11 patients, showing T2 hyperintense lesions in the cerebral white matter in eight cases and a discrete symmetrical T1 hyperintense signal in the globus pallidus in eight patients. A diffuse cortical atrophy was present in three cases and a marked focal atrophy of the corpus callosum in three cases. This series allows us to establish a not previously reported evocative semeiologic MR presentation to precisely orientate to the diagnosis of the pure neurodegenerative form of LCH. (orig.)

  12. Pulmonary Langerhans Cell Histiocytosis Case with Diabetes ...

    African Journals Online (AJOL)

    2017-05-16

    May 16, 2017 ... This is an open access article distributed under the terms of the Creative Commons. Attribution-Non Commercial-Share Alike 3.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical ...

  13. General Information about Langerhans Cell Histiocytosis (LCH)

    Science.gov (United States)

    ... red blood cells, and white blood cells. Water deprivation test : A test to check how much urine ... 4-CANCER (1-800-422-6237). Permission to Use This Summary PDQ is a registered trademark. The ...

  14. Pulmonary Langerhans Cell Histiocytosis Case with Diabetes ...

    African Journals Online (AJOL)

    2016-07-12

    Jul 12, 2016 ... the asymptomatic nature of other system effects because they are still in the early stages. The records of our laden macrophage clusters filling some alveoli around bronchioles, and characteristic respiratory bronchiolitis areas were determined in the fragments prepared from the lung parenchyma with ...

  15. Genetics Home Reference: Langerhans cell histiocytosis

    Science.gov (United States)

    ... to be a form of cancer, but this classification remains controversial. In approximately 80 percent of affected ... due to low numbers of red blood cells ( anemia ), frequent infections due to low numbers of white ...

  16. Dynamic Responsive Systems for Catalytic Function.

    Science.gov (United States)

    Vlatković, Matea; Collins, Beatrice S L; Feringa, Ben L

    2016-11-21

    Responsive systems have recently gained much interest in the scientific community in attempts to mimic dynamic functions in biological systems. One of the fascinating potential applications of responsive systems lies in catalysis. Inspired by nature, novel responsive catalytic systems have been built that show analogy with allosteric regulation of enzymes. The design of responsive catalytic systems allows control of catalytic activity and selectivity. In this Review, advances in the field over the last four decades are discussed and a comparison is made amongst the dynamic responsive systems based on the principles underlying their catalytic mechanisms. The catalyst systems are sorted according to the triggers used to achieve control of the catalytic activity and the distinct catalytic reactions illustrated. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Traffic flow dynamics data, models and simulation

    CERN Document Server

    Treiber, Martin

    2013-01-01

    This textbook provides a comprehensive and instructive coverage of vehicular traffic flow dynamics and modeling. It makes this fascinating interdisciplinary topic, which to date was only documented in parts by specialized monographs, accessible to a broad readership. Numerous figures and problems with solutions help the reader to quickly understand and practice the presented concepts. This book is targeted at students of physics and traffic engineering and, more generally, also at students and professionals in computer science, mathematics, and interdisciplinary topics. It also offers material for project work in programming and simulation at college and university level. The main part, after presenting different categories of traffic data, is devoted to a mathematical description of the dynamics of traffic flow, covering macroscopic models which describe traffic in terms of density, as well as microscopic many-particle models in which each particle corresponds to a vehicle and its driver. Focus chapters on ...

  18. Complex and adaptive dynamical systems a primer

    CERN Document Server

    Gros, Claudius

    2007-01-01

    We are living in an ever more complex world, an epoch where human actions can accordingly acquire far-reaching potentialities. Complex and adaptive dynamical systems are ubiquitous in the world surrounding us and require us to adapt to new realities and the way of dealing with them. This primer has been developed with the aim of conveying a wide range of "commons-sense" knowledge in the field of quantitative complex system science at an introductory level, providing an entry point to this both fascinating and vitally important subject. The approach is modular and phenomenology driven. Examples of emerging phenomena of generic importance treated in this book are: -- The small world phenomenon in social and scale-free networks. -- Phase transitions and self-organized criticality in adaptive systems. -- Life at the edge of chaos and coevolutionary avalanches resulting from the unfolding of all living. -- The concept of living dynamical systems and emotional diffusive control within cognitive system theory. Techn...

  19. Complex and Adaptive Dynamical Systems A Primer

    CERN Document Server

    Gros, Claudius

    2011-01-01

    We are living in an ever more complex world, an epoch where human actions can accordingly acquire far-reaching potentialities. Complex and adaptive dynamical systems are ubiquitous in the world surrounding us and require us to adapt to new realities and the way of dealing with them. This primer has been developed with the aim of conveying a wide range of "commons-sense" knowledge in the field of quantitative complex system science at an introductory level, providing an entry point to this both fascinating and vitally important subject. The approach is modular and phenomenology driven. Examples of emerging phenomena of generic importance treated in this book are: -- The small world phenomenon in social and scale-free networks. -- Phase transitions and self-organized criticality in adaptive systems. -- Life at the edge of chaos and coevolutionary avalanches resulting from the unfolding of all living. -- The concept of living dynamical systems and emotional diffusive control within cognitive system theory. Techn...

  20. A fascinating field and a pragmatic enterprise

    DEFF Research Database (Denmark)

    Hjørland, Birger

    2013-01-01

    A reviewer wrote about the book: "I synnerhet Hjørlands kapitel väcker frågor om fältets inriktning och framtid som det hade varit intressant om redaktörerna hade fångat upp och diskuterat i ett avslutande och syntetiserande kapitel. Detta hade kunnat lyfta denna konferensantologi till något mer ...

  1. Discrepant Events: Why They Fascinate Students.

    Science.gov (United States)

    Shrigley, Robert L.

    1987-01-01

    Describes how discrepant events can be employed as a viable teaching strategy. Reviews the theory of cognitive dissonance and provides examples and approaches in its resolution. Offers samples of discrepancy events and unexpected situations. (ML)

  2. The Fascinating Story of Fossil Fuels

    Science.gov (United States)

    Asimov, Isaac

    1973-01-01

    How this energy source was created, its meaning to mankind, our drastically reduced supply, and why we cannot wait for nature to make more are considered. Today fossil fuels supply 96 percent of the energy used but we must find alternate energy options if we are to combat the energy crisis. (BL)

  3. Childhood sarcoidosis: A rare but fascinating disorder

    Directory of Open Access Journals (Sweden)

    Gedalia Abraham

    2008-09-01

    Full Text Available Abstract Childhood sarcoidosis is a rare multisystemic granulomatous disorder of unknown etiology. In the pediatric series reported from the southeastern United States, sarcoidosis had a higher incidence among African Americans. Most reported childhood cases have occurred in patients aged 13–15 years. Macrophages bearing an increased expression of major histocompatibility class (MHC II molecules most likely initiate the inflammatory response of sarcoidosis by presenting an unidentified antigen to CD4+ Th (helper-inducer lymphocytes. A persistent, poorly degradable antigen driven cell-mediated immune response leads to a cytokine cascade, to granuloma formation, and eventually to fibrosis. Frequently observed immunologic features include depression of cutaneous delayed-type hypersensitivity and a heightened helper T cell type 1 (Th1 immune response at sites of disease. Circulating immune complexes, along with signs of B cell hyperactivity, may also be found. The clinical presentation can vary greatly depending upon the organs involved and age of the patient. Two distinct forms of sarcoidosis exist in children. Older children usually present with a multisystem disease similar to the adult manifestations, with frequent hilar lymphadenopathy and pulmonary infiltrations. Early-onset sarcoidosis is a unique form of the disease characterized by the triad of rash, uveitis, and arthritis in children presenting before four years of age. The diagnosis of sarcoidosis is confirmed by demonstrating a typical noncaseating granuloma on a biopsy specimen. Other granulmatous diseases should be reasonably excluded. The current therapy of choice for sarcoidosis in children with multisystem involvement is oral corticosteroids. Methotrexate given orally in low doses has been effective, safe and steroid sparing in some patients. Alternative immunosuppressive agents, such as azathioprine, cyclophosphamide, chlorambucil, and cyclosporine, have been tried in adult cases of sarcoidosis with questionable efficacy. The high toxicity profile of these agents, including an increased risk of lymphoproliferative disorders and carcinomas, has limited their use to patients with severe disease refractory to other agents. Successful steroid sparing treatment with mycophenolate mofetil was described in an adolescent with renal-limited sarcoidosis complicated by renal failure. Novel treatment strategies for sarcoidosis have been developed including the use of TNF-alpha inhibitors, such as infliximab. The long-term course and prognosis is not well established in childhood sarcoidosis, but it appears to be poorer in early-onset disease.

  4. Natural Antioxidants: Fascinating or Mythical Biomolecules?

    Directory of Open Access Journals (Sweden)

    Johannes Van Staden

    2010-10-01

    Full Text Available Research on the use, properties, characteristics and sources of antioxidants especially phenolic compounds, flavonoids, vitamins, synthetic chemicals and some micronutrients began in the late 18th century. Since then antioxidant research has received considerable attention and over a hundred thousand papers have been published on the subject. This has led to a rampant use of antioxidants in order to try to obtain and preserve optimal health. A number of nutraceuticals and food supplements are frequently fortified with synthetic or natural antioxidants. However, some research outcomes have led to the belief that antioxidants exist as mythical biomolecules. This review provides a critical evaluation of some common in vitro antioxidant capacity methods, and a discussion on the role and controversies surrounding non-enzymatic biomolecules, in particular phenolic compounds and non-phenolic compounds, in oxidative processes in an attempt of stemming the tidal wave that is threatening to swamp the concept of natural antioxidants.

  5. The Fascination of Far-UV Astrophysics

    Science.gov (United States)

    Linsky, J. L.

    1998-05-01

    A one-day topical session will review the observational and theoretical status of astrophysical problems where data in the 900 to 1200 Angstroms range are essential for future advances. The session will include the study of FUV rest wavelengths at high redshifts. For example, the deuterium-to-hydrogen abundance ratio will address the Milky Way and QSO absorption line systems. The FUV spectral region is well known for its unique spectral features and important scientific problems they address. The Lyman series of atomic hydrogen provides the only means to determine the production of deuterium in the Big Bang and its subsequent processing during galactic chemical evolution. The resonance doublet of the O VI ion is the highest temperature resonance line available to study the abundance and kinematics of diffuse hot gas in the disk and halo of the Galaxy and hot gas in accretion disks. The Lyman and Werner bands, the only electronic transitions of molecular hydrogen, probe cold gas in the diffuse ISM as well as the outer regions of dense molecular clouds. Strong transitions of several ionization states of carbon, nitrogen, oxygen, neon, sulphur, and argon provide unique diagnostics for studying interstellar gas and emission plasmas. This special session focuses on recent observational material and how the data limit the range of acceptable pictures. This session will highlight key puzzles and describe anticipated progress from new instrumentation, in particular the Far Ultraviolet Spectroscopic Explorer (FUSE) mission, due to be launched in early 1999. The first talk of the session will summarize the critically important spectral diagnostics that reside in the FUV spectral region and show how they allow FUSE to address the main scientific objectives of FUV astrophysics. FUSE spectra will also enhance the value of longer wavelength spectra provided by HST and IUE, shorter wavelength spectra of EUVE and soon AXAF, lower sensitivity FUV spectra of Copernicus, and lower resolution FUV spectra of ORFEUS.

  6. Natural Antioxidants: Fascinating or Mythical Biomolecules?

    OpenAIRE

    Johannes Van Staden; Mack Moyo; Ashwell R. Ndhlala

    2010-01-01

    Research on the use, properties, characteristics and sources of antioxidants especially phenolic compounds, flavonoids, vitamins, synthetic chemicals and some micronutrients began in the late 18th century. Since then antioxidant research has received considerable attention and over a hundred thousand papers have been published on the subject. This has led to a rampant use of antioxidants in order to try to obtain and preserve optimal health. A number of nutraceuticals and food supplements are...

  7. Transmettre la peur et la fascination

    OpenAIRE

    Berliner, David

    2013-01-01

    à Monchon, un village bulongic aujourd’hui islamisé, la « circoncision de 1954 » fut la dernière initiation masculine. Les vieillards qui ont vécu cet événement clament être « les derniers Bulongic ». Pourtant, le pays bulongic reste héritier de son passé religieux, fait d’initiations, d’entités invisibles, de forêts sacrées et de secrets. L’auteur propose d’explorer le devenir historique d’une société d’initiation et de montrer quel genre de mémoire elle peut mettre en jeu dans le tissu des ...

  8. The Fascination of Knots. The Gordian Knot

    DEFF Research Database (Denmark)

    Hansen, Vagn Lundsgaard

    2000-01-01

    A short discussion of the many fascinatingaspects of knots and links as they arisein mathematics, science and art.......A short discussion of the many fascinatingaspects of knots and links as they arisein mathematics, science and art....

  9. The Fascinating World of Radio Communications.

    Science.gov (United States)

    Green, Wayne, Ed.

    Intended mainly for the amateur radio operator, or "ham," this book outlines some of the pleasures to be had in amateur radio, including DXing (calling distant stations) and helping in emergencies. The steps in starting out on this hobby, including getting Citizens' Band (CB) gear, a CB license, and a receiver and antenna, are described.…

  10. Electrospinning: a fascinating fiber fabrication technique.

    Science.gov (United States)

    Bhardwaj, Nandana; Kundu, Subhas C

    2010-01-01

    With the emergence of nanotechnology, researchers become more interested in studying the unique properties of nanoscale materials. Electrospinning, an electrostatic fiber fabrication technique has evinced more interest and attention in recent years due to its versatility and potential for applications in diverse fields. The notable applications include in tissue engineering, biosensors, filtration, wound dressings, drug delivery, and enzyme immobilization. The nanoscale fibers are generated by the application of strong electric field on polymer solution or melt. The non-wovens nanofibrous mats produced by this technique mimics extracellular matrix components much closely as compared to the conventional techniques. The sub-micron range spun fibers produced by this process, offer various advantages like high surface area to volume ratio, tunable porosity and the ability to manipulate nanofiber composition in order to get desired properties and function. Over the years, more than 200 polymers have been electrospun for various applications and the number is still increasing gradually with time. With these in perspectives, we aim to present in this review, an overview of the electrospinning technique with its promising advantages and potential applications. We have discussed the electrospinning theory, spinnable polymers, parameters (solution and processing), which significantly affect the fiber morphology, solvent properties and melt electrospinning (alternative to solution electrospinning). Finally, we have focused on varied applications of electrospun fibers in different fields and concluded with the future prospects of this efficient technology. (c) 2010 Elsevier Inc. All rights reserved.

  11. Childhood sarcoidosis: A rare but fascinating disorder.

    Science.gov (United States)

    Shetty, Avinash K; Gedalia, Abraham

    2008-09-23

    Childhood sarcoidosis is a rare multisystemic granulomatous disorder of unknown etiology. In the pediatric series reported from the southeastern United States, sarcoidosis had a higher incidence among African Americans. Most reported childhood cases have occurred in patients aged 13-15 years. Macrophages bearing an increased expression of major histocompatibility class (MHC) II molecules most likely initiate the inflammatory response of sarcoidosis by presenting an unidentified antigen to CD4+ Th (helper-inducer) lymphocytes. A persistent, poorly degradable antigen driven cell-mediated immune response leads to a cytokine cascade, to granuloma formation, and eventually to fibrosis. Frequently observed immunologic features include depression of cutaneous delayed-type hypersensitivity and a heightened helper T cell type 1 (Th1) immune response at sites of disease. Circulating immune complexes, along with signs of B cell hyperactivity, may also be found. The clinical presentation can vary greatly depending upon the organs involved and age of the patient. Two distinct forms of sarcoidosis exist in children. Older children usually present with a multisystem disease similar to the adult manifestations, with frequent hilar lymphadenopathy and pulmonary infiltrations. Early-onset sarcoidosis is a unique form of the disease characterized by the triad of rash, uveitis, and arthritis in children presenting before four years of age. The diagnosis of sarcoidosis is confirmed by demonstrating a typical noncaseating granuloma on a biopsy specimen. Other granulmatous diseases should be reasonably excluded. The current therapy of choice for sarcoidosis in children with multisystem involvement is oral corticosteroids. Methotrexate given orally in low doses has been effective, safe and steroid sparing in some patients. Alternative immunosuppressive agents, such as azathioprine, cyclophosphamide, chlorambucil, and cyclosporine, have been tried in adult cases of sarcoidosis with questionable efficacy. The high toxicity profile of these agents, including an increased risk of lymphoproliferative disorders and carcinomas, has limited their use to patients with severe disease refractory to other agents. Successful steroid sparing treatment with mycophenolate mofetil was described in an adolescent with renal-limited sarcoidosis complicated by renal failure. Novel treatment strategies for sarcoidosis have been developed including the use of TNF-alpha inhibitors, such as infliximab. The long-term course and prognosis is not well established in childhood sarcoidosis, but it appears to be poorer in early-onset disease.

  12. Childhood sarcoidosis: A rare but fascinating disorder

    OpenAIRE

    Gedalia Abraham; Shetty Avinash K

    2008-01-01

    Abstract Childhood sarcoidosis is a rare multisystemic granulomatous disorder of unknown etiology. In the pediatric series reported from the southeastern United States, sarcoidosis had a higher incidence among African Americans. Most reported childhood cases have occurred in patients aged 13–15 years. Macrophages bearing an increased expression of major histocompatibility class (MHC) II molecules most likely initiate the inflammatory response of sarcoidosis by presenting an unidentified antig...

  13. The fascinating germ theories on cancer pathogenesis.

    Science.gov (United States)

    Tsoucalas, G; Laios, K; Karamanou, M; Gennimata, V; Androutsos, G

    2014-01-01

    For more than 100 years, the germ theory of cancer, proposing that microorganisms were at the origin of the disease, dominated medicine. Several eminent scientists like Etienne Burnet, Mikhail Stepanovich Voronin, Charles-Louis Malassez, and Francis-Peyton Rous argued on the pathogenesis presenting their theories that implicated cocci, fungi and parasites. The impact of these theories was culminated by the Nobel Prize in 1926 that was attributed to the Danish scientist Johannes Fibiger for his work on the nematode Spiroptera as a causative agent in cancer. Even if those theories were the result of fantasy and misinterpretation, they paved the way for the scientific research in oncology.

  14. The evolutionary dynamics of language.

    Science.gov (United States)

    Steels, Luc; Szathmáry, Eörs

    2018-02-01

    The well-established framework of evolutionary dynamics can be applied to the fascinating open problems how human brains are able to acquire and adapt language and how languages change in a population. Schemas for handling grammatical constructions are the replicating unit. They emerge and multiply with variation in the brains of individuals and undergo selection based on their contribution to needed expressive power, communicative success and the reduction of cognitive effort. Adopting this perspective has two major benefits. (i) It makes a bridge to neurobiological models of the brain that have also adopted an evolutionary dynamics point of view, thus opening a new horizon for studying how human brains achieve the remarkably complex competence for language. And (ii) it suggests a new foundation for studying cultural language change as an evolutionary dynamics process. The paper sketches this novel perspective, provides references to empirical data and computational experiments, and points to open problems. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Spectra and dynamics of small molecules Alexander von Humboldt lectures

    CERN Document Server

    Field, Robert W

    2015-01-01

    These seven lectures are intended to serve as an introduction for beginning graduate students to the spectra of small molecules. The author succeeds in illustrating the concepts by using language and metaphors that capture and elegantly convey simple insights into dynamics that lie beyond archival molecular constants. The lectures can simultaneously be viewed as a collection of interlocking special topics that have fascinated the author and his students over the years. Though neither a textbook nor a scholarly monograph, the book provides an illuminating perspective that will benefit students and researchers alike.

  16. Dynamics of an initially spherical bubble rising in quiescent liquid

    Science.gov (United States)

    Tripathi, Manoj Kumar; Sahu, Kirti Chandra; Govindarajan, Rama

    2015-02-01

    The beauty and complexity of the shapes and dynamics of bubbles rising in liquid have fascinated scientists for centuries. Here we perform simulations on an initially spherical bubble starting from rest. We report that the dynamics is fully three-dimensional, and provide a broad canvas of behaviour patterns. Our phase plot in the Galilei-Eötvös plane shows five distinct regimes with sharply defined boundaries. Two symmetry-loss regimes are found: one with minor asymmetry restricted to a flapping skirt; and another with marked shape evolution. A perfect correlation between large shape asymmetry and path instability is established. In regimes corresponding to peripheral breakup and toroid formation, the dynamics is unsteady. A new kind of breakup, into a bulb-shaped bubble and a few satellite drops is found at low Morton numbers. The findings are of fundamental and practical relevance. It is hoped that experimenters will be motivated to check our predictions.

  17. Dynamics of an initially spherical bubble rising in quiescent liquid.

    Science.gov (United States)

    Tripathi, Manoj Kumar; Sahu, Kirti Chandra; Govindarajan, Rama

    2015-02-17

    The beauty and complexity of the shapes and dynamics of bubbles rising in liquid have fascinated scientists for centuries. Here we perform simulations on an initially spherical bubble starting from rest. We report that the dynamics is fully three-dimensional, and provide a broad canvas of behaviour patterns. Our phase plot in the Galilei-Eötvös plane shows five distinct regimes with sharply defined boundaries. Two symmetry-loss regimes are found: one with minor asymmetry restricted to a flapping skirt; and another with marked shape evolution. A perfect correlation between large shape asymmetry and path instability is established. In regimes corresponding to peripheral breakup and toroid formation, the dynamics is unsteady. A new kind of breakup, into a bulb-shaped bubble and a few satellite drops is found at low Morton numbers. The findings are of fundamental and practical relevance. It is hoped that experimenters will be motivated to check our predictions.

  18. Dynamics and evolution of galactic nuclei (princeton series in astrophysics)

    CERN Document Server

    Merritt, David

    2013-01-01

    Deep within galaxies like the Milky Way, astronomers have found a fascinating legacy of Einstein's general theory of relativity: supermassive black holes. Connected to the evolution of the galaxies that contain these black holes, galactic nuclei are the sites of uniquely energetic events, including quasars, stellar tidal disruptions, and the generation of gravitational waves. This textbook is the first comprehensive introduction to dynamical processes occurring in the vicinity of supermassive black holes in their galactic environment. Filling a critical gap, it is an authoritative resource for astrophysics and physics graduate students, and researchers focusing on galactic nuclei, the astrophysics of massive black holes, galactic dynamics, and gravitational wave detection. It is an ideal text for an advanced graduate-level course on galactic nuclei and as supplementary reading in graduate-level courses on high-energy astrophysics and galactic dynamics. David Merritt summarizes the theoretical work of the las...

  19. Future Satellite Gravimetry and Earth Dynamics

    CERN Document Server

    Flury, Jakob

    2005-01-01

    Currently, a first generation of dedicated satellite missions for the precise mapping of the Earth’s gravity field is in orbit (CHAMP, GRACE, and soon GOCE). The gravity data from these satellite missions provide us with very new information on the dynamics of planet Earth. In particular, on the mass distribution in the Earth’s interior, the entire water cycle (ocean circulation, ice mass balance, continental water masses, and atmosphere), and on changes in the mass distribution. The results are fascinating, but still rough with respect to spatial and temporal resolution. Technical progress in satellite-to-satellite tracking and in gravity gradiometry will allow more detailed results in the future. In this special issue, Earth scientists develop visions of future applications based on follow-on high-precision satellite gravimetry missions.

  20. N=2 supersymmetric dynamics for pedestrians

    CERN Document Server

    Tachikawa, Yuji

    2015-01-01

    Understanding the dynamics of gauge theories is crucial, given the fact that all known interactions are based on the principle of local gauge symmetry. Beyond the perturbative regime, however, this is a notoriously difficult problem. Requiring invariance under supersymmetry turns out to be a suitable tool for analyzing supersymmetric gauge theories over a larger region of the space of parameters. Supersymmetric quantum field theories in four dimensions with extended N=2 supersymmetry are further constrained and have therefore been a fertile field of research in theoretical physics for quite some time. Moreover, there are far-reaching mathematical ramifications that have led to a successful dialogue with differential and algebraic geometry. These lecture notes aim to introduce students of modern theoretical physics to the fascinating developments in the understanding of N=2 supersymmetric gauge theories in a coherent fashion. Starting with a gentle introduction to electric-magnetic duality, the author guides r...

  1. The Stereociliary Paracrystal Is a Dynamic Cytoskeletal Scaffold In Vivo

    Directory of Open Access Journals (Sweden)

    Philsang Hwang

    2015-11-01

    Full Text Available Permanency of mechanosensory stereocilia may be the consequence of low protein turnover or rapid protein renewal. Here, we devise a system, using optical techniques in live zebrafish, to distinguish between these mechanisms. We demonstrate that the stereocilium’s abundant actin cross-linker fascin 2b exchanges, without bias or a phosphointermediate, orders of magnitude faster (t1/2 of 76.3 s than any other known hair bundle protein. To establish the logic of fascin 2b’s exchange, we examine whether filamentous actin is dynamic and detect substantial β-actin exchange within the stereocilium’s paracrystal (t1/2 of 4.08 hr. We propose that fascin 2b’s behavior may enable cross-linking at fast timescales of stereocilia vibration while noninstructively facilitating the slower process of actin exchange. Furthermore, tip protein myosin XVa fully exchanges in hours (t1/2 of 11.6 hr, indicating that delivery of myosin-associated cargo occurs in mature stereocilia. These findings suggest that stereocilia permanency is underpinned by vibrant protein exchange.

  2. Evolutionary dynamics of cooperation in neutral populations

    Science.gov (United States)

    Szolnoki, Attila; Perc, Matjaž

    2018-01-01

    Cooperation is a difficult proposition in the face of Darwinian selection. Those that defect have an evolutionary advantage over cooperators who should therefore die out. However, spatial structure enables cooperators to survive through the formation of homogeneous clusters, which is the hallmark of network reciprocity. Here we go beyond this traditional setup and study the spatiotemporal dynamics of cooperation in a population of populations. We use the prisoner's dilemma game as the mathematical model and show that considering several populations simultaneously gives rise to fascinating spatiotemporal dynamics and pattern formation. Even the simplest assumption that strategies between different populations are payoff-neutral with one another results in the spontaneous emergence of cyclic dominance, where defectors of one population become prey of cooperators in the other population, and vice versa. Moreover, if social interactions within different populations are characterized by significantly different temptations to defect, we observe that defectors in the population with the largest temptation counterintuitively vanish the fastest, while cooperators that hang on eventually take over the whole available space. Our results reveal that considering the simultaneous presence of different populations significantly expands the complexity of evolutionary dynamics in structured populations, and it allows us to understand the stability of cooperation under adverse conditions that could never be bridged by network reciprocity alone.

  3. Memórias de um professor: a instigante história de vida do professor Frederico Michaelsen - A teacher’s memories: the fascinating history of professor Frederico Michaelsen

    Directory of Open Access Journals (Sweden)

    Luiz Alberto de Souza Marques

    2011-03-01

    Full Text Available Resumo O presente estudo apresenta a história de vida do Professor Frederico Michaelsen,  personagem  marcante   na   história   da  educação  do município  de  Nova  Petrópolis  -  RS.  O  eixo principal do  texto consiste numa  carta  endereçada pelo professor ao jornal Deutsche Zeitung de Porto Alegre, em junho de 1889,  em que relata a difícil, e  não menos curiosa, trajetória de um professor nos  primeiros anos da nova colônia, a partir de sua dispensa  do exército brasileiro e do batalhão de artilharia  contratado  na  Alemanha e conhecido como soldados  Brummer.  A  pesquisa não  se atém  somente  aos  dados biográficos do professor Frederico, mas procura  contextualizar, em sua singular trajetória,  as condições  da  sua vinda para o Brasil, a Guerra  contra o ditador  Rosas (Argentina, a permanência no Rio Grande do  Sul,  a vida na nova colônia e o exercício do magistério, entre outras atividades comunitárias que tecem essa  instigante  e curiosa história de vida. A abordagem  adotada para a montagem do trabalho foi a de abertura  do texto da carta e, nele, a inserção dos diferentes    episódios, acompanhando a narrativa de Frederico Michaelsen. Palavras-chave: História  de vida; memória; educação;  história da educação.   A TEACHER’S MEMORIES: THE FASCINATING HISTORY OF PROFESSOR FREDERICO MICHAELSEN – FROM AN IMMIGRANT AND MERCENARY SOLDIER ENGAGED IN THE WAR AGAINST ROSAS (ARGENTINA, IN 1851, TO A PRIMARY TEACHER IN A GERMAN COLONY OF RIO GRANDE DO SUL Abstract This paper presents the history of Professor Frederick  Michaelsen’s life,  a  striking  character  in  the  history   of   education  of  Nova Petropolis, Rio Grande do Sul. The main axis of the text is a letter by the professor to the Deutsche Zeitung newspaper in Porto Alegre, in June  1889,  which reported the difficult, but rather curious story of a professor in

  4. The many faces of graph dynamics

    Science.gov (United States)

    Pignolet, Yvonne Anne; Roy, Matthieu; Schmid, Stefan; Tredan, Gilles

    2017-06-01

    The topological structure of complex networks has fascinated researchers for several decades, resulting in the discovery of many universal properties and reoccurring characteristics of different kinds of networks. However, much less is known today about the network dynamics: indeed, complex networks in reality are not static, but rather dynamically evolve over time. Our paper is motivated by the empirical observation that network evolution patterns seem far from random, but exhibit structure. Moreover, the specific patterns appear to depend on the network type, contradicting the existence of a ‘one fits it all’ model. However, we still lack observables to quantify these intuitions, as well as metrics to compare graph evolutions. Such observables and metrics are needed for extrapolating or predicting evolutions, as well as for interpolating graph evolutions. To explore the many faces of graph dynamics and to quantify temporal changes, this paper suggests to build upon the concept of centrality, a measure of node importance in a network. In particular, we introduce the notion of centrality distance, a natural similarity measure for two graphs which depends on a given centrality, characterizing the graph type. Intuitively, centrality distances reflect the extent to which (non-anonymous) node roles are different or, in case of dynamic graphs, have changed over time, between two graphs. We evaluate the centrality distance approach for five evolutionary models and seven real-world social and physical networks. Our results empirically show the usefulness of centrality distances for characterizing graph dynamics compared to a null-model of random evolution, and highlight the differences between the considered scenarios. Interestingly, our approach allows us to compare the dynamics of very different networks, in terms of scale and evolution speed.

  5. Bioinspired Dynamic Wetting on Multiple Fibers.

    Science.gov (United States)

    Wang, Pengwei; Bian, Ruixin; Meng, Qing'an; Liu, Huan; Jiang, Lei

    2017-10-12

    Natural fibers have versatile strategies for interacting with water media and better adapting to the local environment, and these strategies offer inspiration for the development of artificial functional fibers with diverse applications. Wetting on fibers is a dynamic liquid-moving process on/in fibrous systems with various patterns, and the process is normally driven by the structural gradient, chemical gradient, elasticity of a single fiber, or the synergistic effect of these factors in multiple fibers in an integrated system in which the spatial geometry of the fibers is involved. Compared with the directional liquid movement on a single fiber, wetting on multiple fibers in both the micro- and macroscales is particularly fascinating, with various performances, including directional liquid transport, controllable liquid transfer, efficient liquid encapsulation, and capillary-induced fibrous coalescence. Based on these properties, fibrous materials offer an alternative open system for liquid manipulation that is applicable to various functional liquid materials. Here, recent achievements in bioinspired dynamic wetting on multiple fibers are highlighted, and perspectives on future directions are presented. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Fluid Dynamics of Human Phonation and Speech

    Science.gov (United States)

    Mittal, Rajat; Erath, Byron D.; Plesniak, Michael W.

    2013-01-01

    This article presents a review of the fluid dynamics, flow-structure interactions, and acoustics associated with human phonation and speech. Our voice is produced through the process of phonation in the larynx, and an improved understanding of the underlying physics of this process is essential to advancing the treatment of voice disorders. Insights into the physics of phonation and speech can also contribute to improved vocal training and the development of new speech compression and synthesis schemes. This article introduces the key biomechanical features of the laryngeal physiology, reviews the basic principles of voice production, and summarizes the progress made over the past half-century in understanding the flow physics of phonation and speech. Laryngeal pathologies, which significantly enhance the complexity of phonatory dynamics, are discussed. After a thorough examination of the state of the art in computational modeling and experimental investigations of phonatory biomechanics, we present a synopsis of the pacing issues in this arena and an outlook for research in this fascinating subject.

  7. Multiscale dynamics of C60 from attosecond to statistical physics

    Science.gov (United States)

    Lépine, F.

    2015-06-01

    C60 is a fascinating object that has become remarkably useful for experimentalists and theoreticians to study photo-induced processes in large many-particle systems. In this review article, we discuss how the knowledge accumulated over the past 30 years on this molecule provides a large panel of mechanisms that occur from the intrinsic time scale of electronic motion that is attosecond, to long ‘macroscopic’ time scale (second). This illustrates the multiscale aspect of dynamics in photo-excited systems, which connects coherent quantum processes to classical and statistical mechanisms. This also shines light onto future experiments and theoretical work required to complete the global picture of light-induced mechanisms in fullerenes.

  8. Nuclear dynamical diffraction using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Dennis Eugene [Stanford Univ., CA (United States)

    1993-05-01

    The scattering of synchrotron radiation by nuclei is extensively explored in this thesis. From the multipole electric field expansion resulting from time-dependent nonrelativistic perturbation theory, a dynamical scattering theory is constructed. This theory is shown, in the many particle limit, to be equivalent to the semi-classical approach where a quantum mechanical scattering amplitude is used in the Maxwell inhomogeneous wave equation. The Moessbauer specimen whose low-lying energy levels were probed is a ferromagnetic lattice of 57Fe embedded in a yttrium iron garnet (YIG) crystal matrix. The hyperfine fields in YIG thin films were studied at low and room temperature using time-resolved quantum beat spectroscopy. Nuclear hyperfine structure quantum beats were measured using a fast plastic scintillator coincidence photodetector and associated electronics having a time resolution of 2.5 nsec. The variation of the quantum beat patterns near the Bragg [0 0 2] diffraction peak gave a Lamb-Moessbauer factor of 8.2±0.4. Exploring characteristic dynamical features in the higher order YIG [0 0 10] reflection revealed that one of the YIG crystals had bifurcated into two different layers. The dynamics of nuclear superradiance was explored. This phenomenon includes the radiative speedup exhibited by a collective state of particles, and, in striking concurrence, resonance frequency shifts. A speedup of a factor of 4 in the total decay rate and a beat frequency shift of 11/2 natural resonance linewidths were observed. Nuclear resonance scattering was also found to be a useful way of performing angular interferometry experiments, and it was used to observe the phase shift of a rotated quantum state. On the whole, nuclear dynamical diffraction theory has superbly explained many of the fascinating features of resonant magnetic dipole radiation scattered by a lattice of nuclei.

  9. Beam Dynamics

    CERN Document Server

    Wilson, E

    2013-01-01

    This document is part of Subvolume C 'Accelerators and Colliders' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Chapter '2 Beam Dynamics' with the content: 2 Beam Dynamics 2.1 Linear Transverse Beam Dynamics 2.2 Coupling 2.3 Liouville's Theorem 2.4 Momentum Dependent Transverse Motion 2.5 Longitudinal Motion

  10. Dynamical systems

    CERN Document Server

    Sternberg, Shlomo

    2010-01-01

    Celebrated mathematician Shlomo Sternberg, a pioneer in the field of dynamical systems, created this modern one-semester introduction to the subject for his classes at Harvard University. Its wide-ranging treatment covers one-dimensional dynamics, differential equations, random walks, iterated function systems, symbolic dynamics, and Markov chains. Supplementary materials offer a variety of online components, including PowerPoint lecture slides for professors and MATLAB exercises.""Even though there are many dynamical systems books on the market, this book is bound to become a classic. The the

  11. Dynamics Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Dynamics Lab replicates vibration environments for every Navy platform. Testing performed includes: Flight Clearance, Component Improvement, Qualification, Life...

  12. Development of a Dynamic Virtual Reality Model of the Inner Ear Sensory System as a Learning and Demonstrating Tool

    OpenAIRE

    P. Selva; J. Morlier; Y. Gourinat

    2009-01-01

    In order to keep track of the position and motion of our body in space, nature has given us a fascinating and very ingenious organ, the inner ear. Each inner ear includes five biological sensors - three angular and two linear accelerometers - which provide the body with the ability to sense angular and linear motion of the head with respect to inertial space. The aim of this paper is to present a dynamic virtual reality model of these sensors. This model, implemented in Matlab/Simulink, simul...

  13. The three-body problem and the equations of dynamics Poincaré’s foundational work on dynamical systems theory

    CERN Document Server

    Poincaré, Henri

    2017-01-01

    Here is an accurate and readable translation of a seminal article by Henri Poincaré that is a classic in the study of dynamical systems popularly called chaos theory. In an effort to understand the stability of orbits in the solar system, Poincaré applied a Hamiltonian formulation to the equations of planetary motion and studied these differential equations in the limited case of three bodies to arrive at properties of the equations’ solutions, such as orbital resonances and horseshoe orbits. Poincaré wrote for professional mathematicians and astronomers interested in celestial mechanics and differential equations. Contemporary historians of math or science and researchers in dynamical systems and planetary motion with an interest in the origin or history of their field will find his work fascinating. .

  14. Fluid Dynamics

    DEFF Research Database (Denmark)

    Brorsen, Michael

    These lecture notes are intended mainly for the 7th semester course "Fluid Dynamics" offered by the Study Committee on Civil Engineering, Aalborg University.......These lecture notes are intended mainly for the 7th semester course "Fluid Dynamics" offered by the Study Committee on Civil Engineering, Aalborg University....

  15. Molecular dynamics

    NARCIS (Netherlands)

    Bergstra, J.A.; Bethke, I.

    2002-01-01

    Molecular dynamics is a model for the structure and meaning of object based programming systems. In molecular dynamics the memory state of a system is modeled as a fluid consisting of a collection of molecules. Each molecule is a collection of atoms with bindings between them. A computation is

  16. Discrete dynamics versus analytic dynamics

    DEFF Research Database (Denmark)

    Toxværd, Søren

    2014-01-01

    For discrete classical Molecular dynamics obtained by the “Verlet” algorithm (VA) with the time increment h there exists a shadow Hamiltonian H˜ with energy E˜(h) , for which the discrete particle positions lie on the analytic trajectories for H˜ . Here, we proof that there, independent of such a......For discrete classical Molecular dynamics obtained by the “Verlet” algorithm (VA) with the time increment h there exists a shadow Hamiltonian H˜ with energy E˜(h) , for which the discrete particle positions lie on the analytic trajectories for H˜ . Here, we proof that there, independent...... of such an analytic analogy, exists an exact hidden energy invariance E * for VA dynamics. The fact that the discrete VA dynamics has the same invariances as Newtonian dynamics raises the question, which of the formulations that are correct, or alternatively, the most appropriate formulation of classical dynamics....... In this context the relation between the discrete VA dynamics and the (general) discrete dynamics investigated by Lee [Phys. Lett. B122, 217 (1983)] is presented and discussed....

  17. Nonlinear dynamical triggering of slow slip

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Paul A [Los Alamos National Laboratory; Knuth, Matthew W [WISCONSIN; Kaproth, Bryan M [PENN STATE; Carpenter, Brett [PENN STATE; Guyer, Robert A [Los Alamos National Laboratory; Le Bas, Pierre - Yves [Los Alamos National Laboratory; Daub, Eric G [Los Alamos National Laboratory; Marone, Chris [PENN STATE

    2010-12-10

    Among the most fascinating, recent discoveries in seismology have been the phenomena of triggered slip, including triggered earthquakes and triggered-tremor, as well as triggered slow, silent-slip during which no seismic energy is radiated. Because fault nucleation depths cannot be probed directly, the physical regimes in which these phenomena occur are poorly understood. Thus determining physical properties that control diverse types of triggered fault sliding and what frictional constitutive laws govern triggered faulting variability is challenging. We are characterizing the physical controls of triggered faulting with the goal of developing constitutive relations by conducting laboratory and numerical modeling experiments in sheared granular media at varying load conditions. In order to simulate granular fault zone gouge in the laboratory, glass beads are sheared in a double-direct configuration under constant normal stress, while subject to transient perturbation by acoustic waves. We find that triggered, slow, silent-slip occurs at very small confining loads ({approx}1-3 MPa) that are smaller than those where dynamic earthquake triggering takes place (4-7 MPa), and that triggered slow-slip is associated with bursts of LFE-like acoustic emission. Experimental evidence suggests that the nonlinear dynamical response of the gouge material induced by dynamic waves may be responsible for the triggered slip behavior: the slip-duration, stress-drop and along-strike slip displacement are proportional to the triggering wave amplitude. Further, we observe a shear-modulus decrease corresponding to dynamic-wave triggering relative to the shear modulus of stick-slips. Modulus decrease in response to dynamical wave amplitudes of roughly a microstrain and above is a hallmark of elastic nonlinear behavior. We believe that the dynamical waves increase the material non-affine elastic deformation during shearing, simultaneously leading to instability and slow-slip. The inferred

  18. Dynamic triggering

    Science.gov (United States)

    Hill, David P.; Prejean, Stephanie; Schubert, Gerald

    2015-01-01

    Dynamic stresses propagating as seismic waves from large earthquakes trigger a spectrum of responses at global distances. In addition to locally triggered earthquakes in a variety of tectonic environments, dynamic stresses trigger tectonic (nonvolcanic) tremor in the brittle–plastic transition zone along major plate-boundary faults, activity changes in hydrothermal and volcanic systems, and, in hydrologic domains, changes in spring discharge, water well levels, soil liquefaction, and the eruption of mud volcanoes. Surface waves with periods of 15–200 s are the most effective triggering agents; body-wave trigger is less frequent. Triggering dynamic stresses can be < 1 kPa.

  19. Jumping Dynamics

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2013-01-01

    paradigm the physical scale and henceforth also the massive spectrum of the theory jump at the lower boundary of the conformal window. In particular we propose that a theory can suddenly jump from a Quantum Chromodynamics type spectrum, at the lower boundary of the conformal window, to a conformal one...... without particle interpretation. The jumping scenario, therefore, does not support a near-conformal dynamics of walking type. We will also discuss the impact of jumping dynamics on the construction of models of dynamical electroweak symmetry breaking....

  20. Galactic dynamics

    CERN Document Server

    Binney, James

    2008-01-01

    Since it was first published in 1987, Galactic Dynamics has become the most widely used advanced textbook on the structure and dynamics of galaxies and one of the most cited references in astrophysics. Now, in this extensively revised and updated edition, James Binney and Scott Tremaine describe the dramatic recent advances in this subject, making Galactic Dynamics the most authoritative introduction to galactic astrophysics available to advanced undergraduate students, graduate students, and researchers. Every part of the book has been thoroughly overhauled, and many section

  1. Statics and dynamics of DNA knotting

    Science.gov (United States)

    Orlandini, Enzo

    2018-02-01

    Knots and entanglement in polymers and biopolymers such as DNA and proteins constitute a timely topic that spans various scientific disciplines ranging from physics to chemistry, biology and mathematics. Although in the past many advancements have been made in understanding the equilibrium knotting probability and knot complexity of long polymer chains in solutions, many questions have been addressed in recent years by both experimental and theoretical means—for instance, how the knotting probability depends on the quality of the solvent, the elastic properties of the molecule and its degree of confinement. How knots form, evolve and eventually disappear in a fluctuating chain. Are the equilibrium and non-equilibrium properties of knotted molecules affected by the knot swelling/shrinking dynamics? Moreover, thanks to the great advance in nanotechnology and micromanipulation techniques, nowadays knots can be ‘manually’ tied in a single DNA molecule, followed during their motion along the chains, forced to pass through nanopores, or stretched by external forces or elongational flows. All these experimental approaches allow access to new information on the interplay of topology and polymer physics, and this has opened new perspectives in the field. Here, we provide an overview of the current knowledge of this topic, stressing the main results obtained, including the recent developments in experimental and computational approaches. Since almost all experiments on knotting involve DNA, the review will be mainly focused on the topological properties of this fascinating and biologically relevant molecule.

  2. Cybersecurity Dynamics

    Science.gov (United States)

    2014-08-20

    appropriate threshold cryptosystems or Byzantine fault-tolerance schemes or Moving Target Defense). Cybersecurity Dynamics offers natural security...solution to NP-hard problems ?) 21 Cybersecurity Dynamics Statistics Machine Learning Big Data Analytics Complex System Science Network...meaning that views/ideas can be subject to refinement (or even correction). Note: We are not trying to attain any kind of ver general science (e.g

  3. Sub-cycle control of terahertz high-harmonic generation by dynamical Bloch oscillations

    CERN Document Server

    Schubert, O; Langer, F; Urbanek, B; Lange, C; Huttner, U; Golde, D; Meier, T; Kira, M; Koch, S W; Huber, R

    2016-01-01

    Ultrafast charge transport in strongly biased semiconductors is at the heart of highspeed electronics, electro-optics, and fundamental solid-state physics. Intense light pulses in the terahertz (THz) spectral range have opened fascinating vistas: Since THz photon energies are far below typical electronic interband resonances, a stable electromagnetic waveform may serve as a precisely adjustable bias. Novel quantum phenomena have been anticipated for THz amplitudes reaching atomic field strengths. We exploit controlled THz waveforms with peak fields of 72 MV/cm to drive coherent interband polarization combined with dynamical Bloch oscillations in semiconducting gallium selenide. These dynamics entail the emission of phase-stable high-harmonic transients, covering the entire THz-to-visible spectral domain between 0.1 and 675 THz. Quantum interference of different ionization paths of accelerated charge carriers is controlled via the waveform of the driving field and explained by a quantum theory of inter- and in...

  4. Ultrafast dynamics driven by intense light pulses from atoms to solids, from lasers to intense X-rays

    CERN Document Server

    Gräfe, Stefanie

    2016-01-01

    This book documents the recent vivid developments in the research field of ultrashort intense light pulses for probing and controlling ultrafast dynamics. The recent fascinating results in studying and controlling ultrafast dynamics in ever more complicated systems such as (bio-)molecules and structures of meso- to macroscopic sizes on ever shorter time-scales are presented. The book is written by some of the most eminent experimental and theoretical experts in the field. It covers the new groundbreaking research directions that were opened by the availability of new light sources such as fully controlled intense laser fields with durations down to a single oscillation cycle, short-wavelength laser-driven attosecond pulses and intense X-ray pulses from the upcoming free electron lasers. These light sources allowed the investigation of dynamics in atoms, molecules, clusters, on surfaces and very recently also in nanostructures and solids in new regimes of parameters which, in turn, led to the identification of...

  5. Structural fluctuation governed dynamic diradical character in pentacene.

    Science.gov (United States)

    Yang, Hongfang; Chen, Mengzhen; Song, Xinyu; Bu, Yuxiang

    2015-06-07

    We unravel intriguing dynamical diradical behavior governed by structural fluctuation in pentacene using ab initio molecular dynamics simulation. In contrast to static equilibrium configuration of pentacene with a closed-shell ground state without diradical character, due to structural fluctuation, some of its dynamical snapshot configurations exhibit an open-shell broken-symmetry singlet ground state with diradical character, and such diradical character presents irregular pulsing behavior in time evolution. Not all structural changes can lead to diradical character, only those involving the shortening of cross-linking C-C bonds and variations of the C-C bonds in polyacetylene chains are the main contributors. This scenario about diradicalization is distinctly different from that in long acenes. The essence is that structural distortion cooperatively raises the HOMO and lowers the LUMO, efficiently reducing the HOMO-LUMO and singlet-triplet energy gaps, which facilitate the formation of a broken-symmetry open-shell singlet state. The irregular pulsing behavior originates from the mixing of normal vibrations in pentacene. This fascinating behavior suggests the potential application of pentacene as a suitable building block in the design of new electronic devices due to its magnetism-controllability through energy induction. This work provides new insight into inherent electronic property fluctuation in acenes.

  6. Pulmonary langerhans cell histiocytosis case with diabetes insipidus ...

    African Journals Online (AJOL)

    E Ugurlu, G Altinisik, U Aydogmus, F Bir ... He had a history of smoking 5–10 cigarettes a day for two years, but stopped smoking from the last month. The computerized tomography revealed thin-walled cystic lesions in different sizes more dominantly in the upper lobes and consolidated areas in the left upper and lower ...

  7. Disseminated Langerhan's cell histiocytosis: A case report and ...

    African Journals Online (AJOL)

    Ramakantb

    Nous décrivons la présentation clinique, histopathologie et certaines conclusions immunohistochimie, dans une patiente âgée de huit ans. Mot clés: Disseminated, Histiocytose de cellule du Langerhan. Case Report. Annals of African Medicine Vol. 10, No. 4; 2011. Access this article online. Quick Response Code: Website:.

  8. Diagnostic problems and surgical treatment of histiocytosis X

    Directory of Open Access Journals (Sweden)

    Alkhalil M

    2007-08-01

    Full Text Available A 16-year-old boy, with swelling and pain in the left submandibular region was treated at the Clinic for Maxillofacial Surgery. The x-ray examination showed destructive bone lesion of the mandibulae left side and oval lesions on the left hand bone and ribs. A biopsy showed characteristics of the Hand-Schueller-Christian disease. A surgical treatment consisted of a complete excision of the mandible lesion and reconstruction defect using a rib autologous transplant. After 3 years, osteolysis and extensive process of resorption of the autologous rib bone transplant occurred. Chemotherapy and radiotherapy stopped spreading of the disease for 4 years. However, progression with involvement of the cervical spine with limited motions, pain, and lesions of C5 and C7 appeared. An autologous bone transplant in the reconstruction of the postresection defects in this disease is not recommended.

  9. Percutaneous vertebroplasty in osteoporosis, myeloma and Langerhans' cell histiocytosis.

    LENUS (Irish Health Repository)

    Kevane, B

    2012-01-09

    This review aims to assess the effectiveness of percutaneous vertebroplasty as a treatment for the severe refractory pain associated with vertebral fracture, in a group of patients with fractures secondary to either osteoporotic or neoplastic disease. A retrospective review of 20 patients treated with percutaneous vertebroplasty in Cork University Hospital up until March 2007 was carried out and a questionnaire was prepared and distributed. Prior to vertebroplasty, patients had been symptomatic with severe pain for a mean of 20.9 weeks. Of those thirteen whom replied to a postal questionnaire, 12 (92.3%) reported pain relief and this improvement occurred within 7 days in 9 (81.8%). This was associated with decreased analgesic requirements, as determined on chart review. Prior to the procedure only 5 (38.4%) were independently mobile and this figure rose to 10 (76.9%) afterwards, occurring within one week in the majority. Subjective outcomes were better in the group of patients with neoplasm-induced fractures.

  10. Genetics Home Reference: histiocytosis-lymphadenopathy plus syndrome

    Science.gov (United States)

    ... JF, Pastor-Anglada M, Abel L, Puel A, Govindarajan R, de Pontual L, Casanova JL. A mild ... Jun AH, Bhutia YD, Kannan N, Unadkat JD, Govindarajan R. Human equilibrative nucleoside transporter-3 (hENT3) spectrum ...

  11. Atlantoaxial Langerhans cell histiocytosis radiographic characteristics and corresponding prognosis analysis

    Directory of Open Access Journals (Sweden)

    Lihua Zhang

    2017-01-01

    Conclusions: The atlas and axis were affected by LCH, mainly in children. The lateral mass was easily affected and compressed, destruction of the atlas and axis could lead to atlantoaxial joint instability. The prognosis was good in most of the patients.

  12. Langerhans cell histiocytosis: A case presentation and literature ...

    African Journals Online (AJOL)

    a complete blood count with differential counts, renal and liver function tests, measurement of .... Langerhans cells express characteristic cell surface proteins called the CD1a protein and langerin. These cells can ... Hepatic involvement is defined as hepatic enlargement, liver function test abnormalities and/or histological ...

  13. Langerhans cell histiocytosis: A case presentation and literature ...

    African Journals Online (AJOL)

    Once the diagnosis has been confirmed, all cases should be referred to a paediatric oncologist for risk stratification and further management. We present a case of a toddler with LCH with skeletal involvement, who primarily presented to an orthopaedic surgeon. Relevant knowledge about this condition is reviewed.

  14. Record dynamics

    DEFF Research Database (Denmark)

    Robe, Dominic M.; Boettcher, Stefan; Sibani, Paolo

    2016-01-01

    When quenched rapidly beyond their glass transition, colloidal suspensions fall out of equilibrium. The pace of their dynamics then slows down with the system age, i.e., with the time elapsed after the quench. This breaking of time translational invariance is associated with dynamical observables...... which depend on two time-arguments. The phenomenology is shared by a broad class of aging systems and calls for an equally broad theoretical description. The key idea is that, independent of microscopic details, aging systems progress through rare intermittent structural relaxations that are de......-facto irreversible and become increasingly harder to achieve. Thus, a progression of record-sized dynamical barriers are traversed in the approach to equilibration. Accordingly, the statistics of the events is closely described by a log-Poisson process. Originally developed for relaxation in spin glasses...

  15. Dynamic Bifurcations

    CERN Document Server

    1991-01-01

    Dynamical Bifurcation Theory is concerned with the phenomena that occur in one parameter families of dynamical systems (usually ordinary differential equations), when the parameter is a slowly varying function of time. During the last decade these phenomena were observed and studied by many mathematicians, both pure and applied, from eastern and western countries, using classical and nonstandard analysis. It is the purpose of this book to give an account of these developments. The first paper, by C. Lobry, is an introduction: the reader will find here an explanation of the problems and some easy examples; this paper also explains the role of each of the other paper within the volume and their relationship to one another. CONTENTS: C. Lobry: Dynamic Bifurcations.- T. Erneux, E.L. Reiss, L.J. Holden, M. Georgiou: Slow Passage through Bifurcation and Limit Points. Asymptotic Theory and Applications.- M. Canalis-Durand: Formal Expansion of van der Pol Equation Canard Solutions are Gevrey.- V. Gautheron, E. Isambe...

  16. Dynamical systems

    CERN Document Server

    Birkhoff, George D

    1927-01-01

    His research in dynamics constitutes the middle period of Birkhoff's scientific career, that of maturity and greatest power. -Yearbook of the American Philosophical Society The author's great book€¦is well known to all, and the diverse active modern developments in mathematics which have been inspired by this volume bear the most eloquent testimony to its quality and influence. -Zentralblatt MATH In 1927, G. D. Birkhoff wrote a remarkable treatise on the theory of dynamical systems that would inspire many later mathematicians to do great work. To a large extent, Birkhoff was writing about his o

  17. Delta Dynamics

    DEFF Research Database (Denmark)

    Bendixen, Mette

    . The warming air temperature affects the soil temperature and permafrost thaws and destabilizes the material in the coastal zone. In Greenland, the warming temperature lowers the surface mass balance of the Greenland Ice Sheet and more material is transported to the coastal zone. The sea ice extent is thinning...... of a fjord and the second type is a wider fan-shaped open delta. Most deltas are directly coupled to the Greenland Ice Sheet or local icecaps and are highly influenced by the dynamics in the catchments. It is demonstrated how a modern changing climate directly affects delta dynamics, and that Greenlandic...

  18. Dynamical theory of dense groups of galaxies

    Science.gov (United States)

    Mamon, Gary A.

    1990-01-01

    It is well known that galaxies associate in groups and clusters. Perhaps 40% of all galaxies are found in groups of 4 to 20 galaxies (e.g., Tully 1987). Although most groups appear to be so loose that the galaxy interactions within them ought to be insignificant, the apparently densest groups, known as compact groups appear so dense when seen in projection onto the plane of the sky that their members often overlap. These groups thus appear as dense as the cores of rich clusters. The most popular catalog of compact groups, compiled by Hickson (1982), includes isolation among its selection critera. Therefore, in comparison with the cores of rich clusters, Hickson's compact groups (HCGs) appear to be the densest isolated regions in the Universe (in galaxies per unit volume), and thus provide in principle a clean laboratory for studying the competition of very strong gravitational interactions. The $64,000 question here is then: Are compact groups really bound systems as dense as they appear? If dense groups indeed exist, then one expects that each of the dynamical processes leading to the interaction of their member galaxies should be greatly enhanced. This leads us to the questions: How stable are dense groups? How do they form? And the related question, fascinating to any theorist: What dynamical processes predominate in dense groups of galaxies? If HCGs are not bound dense systems, but instead 1D change alignments (Mamon 1986, 1987; Walke & Mamon 1989) or 3D transient cores (Rose 1979) within larger looser systems of galaxies, then the relevant question is: How frequent are chance configurations within loose groups? Here, the author answers these last four questions after comparing in some detail the methods used and the results obtained in the different studies of dense groups.

  19. Classical dynamics

    CERN Document Server

    Greenwood, Donald T

    1997-01-01

    Graduate-level text for science and technology students provides strong background in the more abstract and intellectually satisfying areas of dynamical theory. Topics include d'Alembert's principle and the idea of virtual work, Hamilton's equations, Hamilton-Jacobi theory, canonical transformations, more. Problems and references at chapter ends.

  20. Dynamic Assessment.

    Science.gov (United States)

    Schoel, Jim

    1998-01-01

    Adventure therapists are often asked to assess clients in a manner that differs from their therapeutic approach, resulting in assessment being perceived as burdensome. Project Adventure's Decision Tree combines assessment with activity selection to create a dynamic tool that is responsive to group, individual, and leader needs. Example focuses on…

  1. Structural dynamics

    CERN Document Server

    Strømmen, Einar N

    2014-01-01

    This book introduces to the theory of structural dynamics, with focus on civil engineering structures that may be described by line-like beam or beam-column type of systems, or by a system of rectangular plates. Throughout this book the mathematical presentation contains a classical analytical description as well as a description in a discrete finite element format, covering the mathematical development from basic assumptions to the final equations ready for practical dynamic response predictions. Solutions are presented in time domain as well as in frequency domain. Structural Dynamics starts off at a basic level and step by step brings the reader up to a level where the necessary safety considerations to wind or horizontal ground motion induced dynamic design problems can be performed. The special theory of the tuned mass damper has been given a comprehensive treatment, as this is a theory not fully covered elsewhere. For the same reason a chapter on the problem of moving loads on beams has been included.

  2. Membrane dynamics

    DEFF Research Database (Denmark)

    Bendix, Pól Martin

    2015-01-01

    Current topics include membrane-protein interactions with regard to membrane deformation or curvature sensing by BAR domains. Also, we study the dynamics of membrane tubes of both cells and simple model membrane tubes. Finally, we study membrane phase behavior which has important implications...... for the lateral organization of membranes as wells as for physical properties like bending, permeability and elasticity...

  3. Glassy Dynamics

    DEFF Research Database (Denmark)

    Jensen, Henrik J.; Sibani, Paolo

    2007-01-01

    The term glassy dynamics is often used to refer to the extremely slow relaxation observed in several types of many component systems. The time span needed to reach a steady, time independent, state will typically be far beyond experimentally accessible time scales. When melted alloys are cooled d...

  4. Pillar[5]arenes: fascinating cyclophanes with a bright future.

    Science.gov (United States)

    Cragg, Peter J; Sharma, Kushal

    2012-01-21

    Pillar[5]arenes are [1(5)]paracyclophane derivatives consisting of 1,4-disubstituted hydroquinones linked by methylene bridges in the 2,5-positions. The first report of these novel macrocycles was in 2008, when 1,4-dimethoxypillar[5]arene was prepared in 22% yield, and subsequent improvements in synthetic methods have allowed the number of derivatives to expand significantly. In addition to D(5) symmetric pillar[5]arenes, asymmetric pillar[5]arenes with two different substituents in the 1- and 4-positions and copillar[5]arenes consisting of two different repeat units in a 4 : 1 ratio have been synthesised. Crystallographic, computational and spectroscopic studies are starting to shed light on the compounds' unusual inclusion phenomena, from gelation and transportation of water through nanotubes to the formation of chromogenic rotaxanes. Applications as molecular sensors are starting to appear with a focus on guest detection by fluorescence quenching. This tutorial review will provide a summary of research into the pillar[5]arenes since their recent discovery.

  5. Babies' Fascination with Faces May Start in the Womb

    Science.gov (United States)

    ... like shapes," said study author Vincent Reid, a psychology professor at Lancaster University in England. The investigators ... were published June 8 in the journal Current Biology . "This preference has been recognized in babies for ...

  6. The Swedish Bohus granite - a stone with a fascinating history

    Science.gov (United States)

    Schouenborg, Björn; Eliasson, Thomas

    2015-04-01

    One of the most well-known and well spread Swedish stone types used as building stones is the Bonus granite. It outcrops in an area north of Gothenburgh (SW Sweden), along the coastline, approximately 35 km wide and 85 km long. The granite continues into Norway as the Iddefjord granite. The Bohus granite is one of Sweden's youngest granites. Isotopic dating shows that the magma cooled at about 920 M years ago and thus marking the end of the Sveconorwegian orogoney. It is a composite granite massif area with several granitic intrusions but with rather homogeneous mineralogy. However, colour and texture varies quite a lot and the colour ranges from red to reddish grey although some pure grey varieties occur sparsely. The grain size ranges from medium grained to coarse grained and even with some porphyric parts. Quarrying in an industrial scale started 1842. The merchant A C Kullgren opened the first quarry and produced stones for the construction of the 86 km long Trollhättan channel connecting lake Vänern and the Atlantic ocean in the SW Sweden The stone was used for constructing harbors and wharves along the channel. Several quarries opened in the late 1800 around 1870 - 1890 and the export increased steadily with deliveries to Germany, Denmark, Holland, England and even to South America. The stone industries in Bohuslän (Bohus county), at its peak in 1929, engaged around 7 000 employees. During the depression in 1930 almost all of them became unemployed. However, as a curiosity, production and export continued to Germany for construction of Germania, the future World capital city ("Welthauptstadt Germania"), planned by Adolf Hitler and Albert Speer. About 500 stone workers were kept employed for this project during the late thirties. Today several varieties are still produced: Evja/Ävja, Tossene, Brastad, Näsinge, Broberg, Nolby, Allemarken and Skarstad. However, the number of stone workers is far from that of the early 1900. The Swedish production is mainly blocks but also paving products like sets, slabs and kerb stones are still manufactured in Sweden. Blocks are generally further processed in other countries like Italy and China to reach the European market as semi-finished products like slabs or finished products for any kind of application. The granite is very durable and suitable for all types of natural stone products.

  7. Beautiful Death: the Nineteenth-Century Fascination with Antigone

    OpenAIRE

    Beaney, Tara

    2009-01-01

    This article investigates the reception of Sophocles’ Antigone in early nineteenth-century Germany, a period in which interest in ancient Greek tragedy flourished, with Antigone being particularly prominent. The essay considers two influential figures of the period who regarded the work highly: the philosopher G.W.F. Hegel (1770-1831) and the poet Friedrich Hölderlin (1770- 1843). In discussing their attitudes towards Antigone, the article raises the long-standing philosophical problem of how...

  8. This Gun for Hire: The Fascination of Movie Assassins

    Science.gov (United States)

    Beck, Bernard

    2005-01-01

    The main characters in a movie can serve individuals in many different ways, but the usual way is to appear good. In whatever form, stories of individuals are a useful part of popular culture when they offer models of how individuals might save themselves or be saved. However, there are other ways. Villains, monsters, and enemies can be at the…

  9. Single Molecule Fluorescence: from Physical Fascination to Biological Relevance

    NARCIS (Netherlands)

    Segers-Nolten, Gezina M.J.

    2003-01-01

    Confocal fluorescence microscopy is particularly well-known from the beautiful images that have been obtained with this technique from cells. Several cellular components could be nicely visualized simultaneously by staining them with different fluorophores. Not only for ensemble applications but

  10. Familial mediterranean fever: a fascinating model of inherited autoinflammatory disorder.

    Science.gov (United States)

    Portincasa, Piero; Scaccianoce, Giuseppe; Palasciano, Giuseppe

    2013-12-01

    Familial Mediterranean fever (FMF) is a rare inherited autosomal recessive autoinflammatory disorder characterized by recurrent and self-limited episodes of fever and painful serositis, lasting 1-3 days. FMF occurs almost exclusively among ethnic groups of the Mediterranean basin, although cases have also been found in Japan and Korean populations. Diagnosis is based on clinical features, response to colchicine and genetic analysis. Novel drugs are emerging, allowing better management of colchicine-resistant/colchicine-intolerant patients. This review aims to attract the attention of the readers on differential diagnosis and management of patients with FMF. The current state-of-the-art on FMF is outlined, with respect to epidemiological, genetic, pathophysiological and therapeutic characteristics, based on critical analysis of solid scientific literature. FMF is more frequent than it was thought before. The phenotypic expression of M694V is more severe than that of V726A. Patients with M694V/M694V homozygosity are exposed to a higher risk of developing renal amyloidosis, arthritis, dermatologic and oral lesions, higher fever and more frequent painful attacks. Life-long therapy with colchicine (1·0-2·4 mg/day) is effective and safe to prevent recurrent attacks and renal amyloidosis and to reverse proteinuria. In nonresponder patients, alternative novel approaches include interleukin-1 receptor antagonist anakinra and the interleukin-1 decoy receptor rilonacept. The prognosis of FMF is normal if AA amyloidosis is prevented. Colchicine remains the first-line therapy to treat pain and prevent amyloidosis. A follow-up should include clinical evaluation, therapeutic adjustments, measurement of serum amyloid A and proteinuria. © 2013 Stichting European Society for Clinical Investigation Journal Foundation. Published by John Wiley & Sons Ltd.

  11. New methods for assessing the fascinating nature of nature experiences

    OpenAIRE

    Joye, Yannick; Pals, R.; Steg, L.; Lewis-Evans, B.

    2013-01-01

    In recent years, numerous environmental psychology studies have demonstrated that contact with nature as opposed to urban settings can improve an individual’s mood, can lead to increased levels of vitality, and can offer an opportunity to recover from stress. According to Attention Restoration Theory (ART) the restorative potential of natural environments is situated in the fact that nature can replenish depleted attentional resources. This replenishment takes place, in part, because nature i...

  12. New Methods for Assessing the Fascinating Nature of Nature Experiences

    NARCIS (Netherlands)

    Joye, Yannick; Pals, Roos; Steg, Linda; Evans, Ben Lewis

    2013-01-01

    In recent years, numerous environmental psychology studies have demonstrated that contact with nature as opposed to urban settings can improve an individual's mood, can lead to increased levels of vitality, and can offer an opportunity to recover from stress. According to Attention Restoration

  13. New Methods for Assessing the Fascinating Nature of Nature Experiences

    OpenAIRE

    Joye, Yannick; Pals, Roos; Steg, Linda; Evans, Ben Lewis

    2013-01-01

    In recent years, numerous environmental psychology studies have demonstrated that contact with nature as opposed to urban settings can improve an individual's mood, can lead to increased levels of vitality, and can offer an opportunity to recover from stress. According to Attention Restoration Theory (ART) the restorative potential of natural environments is situated in the fact that nature can replenish depleted attentional resources. This replenishment takes place, in part, because nature i...

  14. New methods for assessing the fascinating nature of nature experiences

    NARCIS (Netherlands)

    Yannick Joye; Linda Steg; Ben Lewis Evans; Roos Pals

    2013-01-01

    In recent years, numerous environmental psychology studies have demonstrated that contact with nature as opposed to urban settings can improve an individual’s mood, can lead to increased levels of vitality, and can offer an opportunity to recover from stress. According to Attention Restoration

  15. Fascinating and forgotten: the conservation status of marine elapid snakes

    DEFF Research Database (Denmark)

    Redsted Rasmussen, Arne

    2013-01-01

    Abstract.—An assessment of marine elapid snakes found 9% of marine elapids are threatened with extinction, and an additional 6% are Near Threatened. A large portion (34%) is Data Deficient. An analysis of distributions revealed the greatest species diversity is found in Southeast Asia and norther...

  16. The Fascinating Effects of Baicalein on Cancer: A Review

    Directory of Open Access Journals (Sweden)

    Hui Liu

    2016-10-01

    Full Text Available Cancer is one of the leading causes of death worldwide and a major global health problem. In recent decades, the rates of both mortality and morbidity of cancer have rapidly increased for a variety of reasons. Despite treatment options, there are serious side effects associated with chemotherapy drugs and multiple forms of drug resistance that significantly reduce their effects. There is an accumulating amount of evidence on the pharmacological activities of baicalein (e.g., anti-inflammatory, antioxidant, antiviral, and antitumor effects. Furthermore, there has been great progress in elucidating the target mechanisms and signaling pathways of baicalein’s anti-cancer potential. The anti-tumor functions of baicalein are mainly due to its capacities to inhibit complexes of cyclins to regulate the cell cycle, to scavenge oxidative radicals, to attenuate mitogen activated protein kinase (MAPK, protein kinase B (Akt or mammalian target of rapamycin (mTOR activities, to induce apoptosis by activating caspase-9/-3 and to inhibit tumorinvasion and metastasis by reducing the expression of matrix metalloproteinase-2/-9 (MMP-2/-9. In this review, we focused on the relevant biological mechanisms of baicalein involved in inhibiting various cancers, such as bladder cancer, breast cancer, and ovarian cancer. Moreover, we also summarized the specific mechanisms by which baicalein inhibited the growth of various tumors in vivo. Taken together, baicalein may be developed as a potential, novel anticancer drug to treat tumors.

  17. Alpha-fetoprotein, a fascinating protein and biomarker in neurology

    NARCIS (Netherlands)

    Schieving, J.H.; Vries, M. de; Vugt, J.M.G. van; Weemaes, C.M.R.; Deuren, M. van; Nicolai, J.; Wevers, R.A.; Willemsen, M.A.

    2014-01-01

    Alpha-fetoprotein (AFP) is present in fetal serum in concentrations up to 5,000,000 mug/l. After birth, AFP gene expression is turned down with a subsequent fall of the serum concentrations of this albumin-like protein to 'adult values' of circa 0.5-15 mug/l from the age of 2 years onwards.

  18. Marvels of Math: Fascinating Reads and Awesome Activities.

    Science.gov (United States)

    Haven, Kendall F.

    Any topic, math included, becomes more accessible and understandable when human stories are related about the development of the subject. Stories make subjects real and purposeful. They provide a foundation from which students can understand and appreciate mathematics rather than merely memorize a series of rote exercises. This book presents 16…

  19. Marvels of Science: 50 Fascinating 5-minute Reads.

    Science.gov (United States)

    Haven, Kendall

    This book is a collection of 50 stories of the people, events, and processes that give us our rich scientific heritage with the goal of fostering an appreciation for the process of science and for the great variety of personalities that have graced the world of science. In addition to the actual text, each story in this book contains focusing and…

  20. Fascinating Technology: Computer Games as an Issue for Religious Education

    Science.gov (United States)

    Scholtz, Christopher P.

    2005-01-01

    Computer games as an important part of youth culture can, from a certain perspective, be highly relevant for religious education. I will review the role of computer games, and then give a brief overview, suggesting a specific phenomenological approach for research on computer games and religious education. After presenting one example of such…

  1. Use of renewable energies at sea: Fascination Offshore. Report 2002

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    Wind energy use experienced an enormous upswing in recent years. In the meantime a wind energy capacity of more than 26,000 MW has been installed worldwide and this positive development appears to continue at the same pace. According to a study of the renowned consulting company BTM Consult an additional capacity of 54,000 MW will be installed in the next five years. Apart from the development in the onshore area and the gained experience, the large-scale technical utilisation of wind power at sea in Europe becomes more and more the focus of attention. The planned wind power plants are supposed to have a capacity between three and five MW and the number of plants in the final extension phase is supposed to amount to 200 plants, which corresponds to an installed capacity of up to 1,000 MW per park. Plans are partly made for plants located between 30 and 40 kilometres from the coast and in water depths of up to 35 meters. Research results about the wind conditions and the location requirements at these distances from the coast are only available to a certain extent. In order to obtain reliable data several research projects have been initiated. In this study you will not only find contributions to the subjects mentioned above but also reports from experts, who explain their knowledge and experience gained from practice. (orig.) [German] Die Windenergienutzung hat in den letzten Jahren einen ernormen Aufschwung erlebt. Mittlerweile sind weltweit mehr als 26.000 MW an Windenergieleistung installiert und diese positive Entwicklung geht offensichtlich ungebremst weiter. Gemaess einer Studie des renommierten Beratungsunternehmens BTM Consult werden in den naechsten fuenf Jahren weitere 54.000 MW errichtet. Neben der Entwicklung im Onshore-Bereich und der dort gesammelten Erfahrung rueckt nun die grosstechnische Nutzung der Windkraft auf dem Meer in Europa immer mehr in den Blickpunkt. Die zum Einsatz kommenden WEA sollen eine Leistung von drei bis fuenf MW haben und die Anlagenzahl betraegt in den Endausbaustufen bis zu 200 Anlagen, was einer installierte Leistung von bis zu 1.000 MW pro Park entspricht. Die Planungen werden zum Teil in Kuestenentfernungen von 30 bis 40 Kilometern und in Wassertiefen bis zu 35 Metern durchgefuehrt. In diesen Entfernungen von der Kueste liegen nur bedingt Forschungsergebnisse ueber Windverhaeltnisse und Standortanforderungen vor. Um hier belastbare Daten zu erhalten sind diverse Forschungsvorhaben initiiert worden. In der Studie finden Sie neben unseren eigenen Ausarbeitungen zu den oben genannten Themenbereichen auch Fachbeitraege von Experten, die aus der Praxis heraus Ihre Erfahrungen und Kenntnisse einfliessen lassen. (orig.)

  2. Fascinating! Popular Science Communication and Literary Science Fiction

    DEFF Research Database (Denmark)

    Meyer, Gitte

    2017-01-01

    Some see literary Science Fiction as a possible vehicle for critical discussions about the future development and the ethical implications of science-based technologies. According to that understanding, literary Science Fiction constitutes a variety of science communication. Along related lines, ...

  3. ATLASES—THE NEW FASCINATION OF FRENCH PUBLISHERS

    Directory of Open Access Journals (Sweden)

    Jean Radvanyi

    2011-01-01

    Full Text Available Reacting to reader interest in publications of new types of atlases, many French authors and publishers rushed to occupy an emerging publishing niche and created a real fashion of small atlases attracting ever-greater public attention. The paper describes origins and features of this phenomenon.

  4. Contemplating Allan Boesak's fascination with preaching “Truth to ...

    African Journals Online (AJOL)

    Preaching can rightly be called “foolishness”, an outdated form of communication and a feeble form of art. In democratic South Africa, preaching is certainly not assigned a place among the ranks of professions conveying “development”. Allan Boesak, however, has not been swayed by the excommunication of preaching ...

  5. Fluid dynamics

    CERN Document Server

    Bernard, Peter S

    2015-01-01

    This book presents a focused, readable account of the principal physical and mathematical ideas at the heart of fluid dynamics. Graduate students in engineering, applied math, and physics who are taking their first graduate course in fluids will find this book invaluable in providing the background in physics and mathematics necessary to pursue advanced study. The book includes a detailed derivation of the Navier-Stokes and energy equations, followed by many examples of their use in studying the dynamics of fluid flows. Modern tensor analysis is used to simplify the mathematical derivations, thus allowing a clearer view of the physics. Peter Bernard also covers the motivation behind many fundamental concepts such as Bernoulli's equation and the stream function. Many exercises are designed with a view toward using MATLAB or its equivalent to simplify and extend the analysis of fluid motion including developing flow simulations based on techniques described in the book.

  6. Dynamic Gossip

    OpenAIRE

    van Ditmarsch, Hans; Eijck, Jan van; Pardo, Pere; Ramezanian, Rahim; Schwartzentruber, Francois

    2016-01-01

    textabstractA gossip protocol is a procedure for spreading secrets among a group of agents, using a connection graph. We consider distributed gossip protocols wherein the agents themselves instead of a global scheduler determine whom to call. In this paper the problem of designing and analyzing gossip protocols is given a dynamic twist by assuming that when a call is established not only secrets are exchanged but also telephone numbers. Both numbers and secrets can be represented by edges in ...

  7. Dynamic Terrin

    Science.gov (United States)

    1991-12-30

    amount of computation for each iteration makes a real time simulation beyond the reach of current computer hardware. Also in 1986, Darwyn Peachy ... Peachy 861 introduced an ocean model to produce realistic images of waves on a beach. He uses a phase function to model wave refraction and the change of...and C. Lisle, Dynamic Terrain Databases on Networked Simulators, Proceedings of the IMAGE VI Conference, Phoenix AZ, July 1992, to appear. [ Peachy 86

  8. Invisible Electronic States and Their Dynamics Revealed by Perturbations

    Science.gov (United States)

    Merer, Anthony J.

    2011-06-01

    Sooner or later everyone working in the field of spectroscopy encounters perturbations. These can range in size from a small shift of a single rotational level to total destruction of the vibrational and rotational patterns of an electronic state. To some workers perturbations are a source of terror, but to others they are the most fascinating features of molecular spectra, because they give information about molecular dynamics, and about states that would otherwise be invisible as a result of unfavorable selection rules. An example of the latter is the essentially complete characterization of the tilde{b}^3A_2 state of SO_2 from the vibronic perturbations it causes in the tilde{a}^3B_1 state. The S_1-trans state of acetylene is a beautiful example of dynamics in action. The level patterns of the three bending vibrations change dramatically with increasing vibrational excitation as a result of the vibrational angular momentum and the approach to the isomerization barrier. Several vibrational levels of the S_1-cis isomer, previously thought to be unobservable, can now be assigned. They obtain their intensity through interactions with nearby levels of the trans isomer.

  9. Application of Hybrid Dynamical Theory to the Cardiovascular System

    KAUST Repository

    Laleg-Kirati, Taous-Meriem

    2014-10-14

    In hybrid dynamical systems, the state evolves in continuous time as well as in discrete modes activated by internal conditions or by external events. In the recent years, hybrid systems modeling has been used to represent the dynamics of biological systems. In such systems, discrete behaviors might originate from unexpected changes in normal performance, e.g., a transition from a healthy to an abnormal condition. Simplifications, model assumptions, and/or modeled (and ignored) nonlinearities can be represented by sudden changes in the state. Modeling cardiovascular system (CVS), one of the most fascinating but most complex human physiological systems, with a hybrid approach, is the focus of this chapter. The hybrid property appears naturally in the CVS thanks to the presence of valves which, depending on their state (closed or open), divide the cardiac cycle into four phases. This chapter shows how hybrid models can be used for modeling the CVS. In addition, it describes a preliminary study on the detection of some cardiac anomalies based on the hybrid model and using the standard observer-based approach.

  10. Modeling light-induced charge transfer dynamics across a metal-molecule-metal junction: bridging classical electrodynamics and quantum dynamics.

    Science.gov (United States)

    Hu, Zixuan; Ratner, Mark A; Seideman, Tamar

    2014-12-14

    We develop a numerical approach for simulating light-induced charge transport dynamics across a metal-molecule-metal conductance junction. The finite-difference time-domain method is used to simulate the plasmonic response of the metal structures. The Huygens subgridding technique, as adapted to Lorentz media, is used to bridge the vastly disparate length scales of the plasmonic metal electrodes and the molecular system, maintaining accuracy. The charge and current densities calculated with classical electrodynamics are transformed to an electronic wavefunction, which is then propagated through the molecular linker via the Heisenberg equations of motion. We focus mainly on development of the theory and exemplify our approach by a numerical illustration of a simple system consisting of two silver cylinders bridged by a three-site molecular linker. The electronic subsystem exhibits fascinating light driven dynamics, wherein the charge density oscillates at the driving optical frequency, exhibiting also the natural system timescales, and a resonance phenomenon leads to strong conductance enhancement.

  11. Hamiltonian dynamics

    CERN Document Server

    Vilasi, Gaetano

    2001-01-01

    This is both a textbook and a monograph. It is partially based on a two-semester course, held by the author for third-year students in physics and mathematics at the University of Salerno, on analytical mechanics, differential geometry, symplectic manifolds and integrable systems. As a textbook, it provides a systematic and self-consistent formulation of Hamiltonian dynamics both in a rigorous coordinate language and in the modern language of differential geometry. It also presents powerful mathematical methods of theoretical physics, especially in gauge theories and general relativity. As a m

  12. PREFACE: Cooperative dynamics Cooperative dynamics

    Science.gov (United States)

    Gov, Nir

    2011-09-01

    The dynamics within living cells are dominated by non-equilibrium processes that consume chemical energy (usually in the form of ATP, adenosine triphosphate) and convert it into mechanical forces and motion. The mechanisms that allow this conversion process are mostly driven by the components of the cytoskeleton: (i) directed (polar) polymerization of filaments (either actin or microtubules) and (ii) molecular motors. The forces and motions produced by these two components of the cytoskeleton give rise to the formation of cellular shapes, and drive the intracellular transport and organization. It is clear that these systems present a multi-scale challenge, from the physics of the molecular processes to the organization of many interacting units. Understanding the physical nature of these systems will have a large impact on many fundamental problems in biology and break new grounds in the field of non-equilibrium physics. This field of research has seen a rapid development over the last ten years. Activities in this area range from theoretical and experimental work on the underlying fundamental (bio)physics at the single-molecule level, to investigations (in vivo and in vitro) of the dynamics and patterns of macroscopic pieces of 'living matter'. In this special issue we have gathered contributions that span the whole spectrum of length- and complexity-scales in this field. Some of the works demonstrate how active forces self-organize within the polymerizing cytoskeleton, on the level of cooperative cargo transport via motors or due to active fluxes at the cell membrane. On a larger scale, it is shown that polar filaments coupled to molecular motors give rise to a huge variety of surprising dynamics and patterns: spontaneously looping rings of gliding microtubules, and emergent phases of self-organized filaments and motors in different geometries. All of these articles share the common feature of being out-of-equilibrium, driven by metabolism. As demonstrated here

  13. Complex dynamics

    CERN Document Server

    Carleson, Lennart

    1993-01-01

    Complex dynamics is today very much a focus of interest. Though several fine expository articles were available, by P. Blanchard and by M. Yu. Lyubich in particular, until recently there was no single source where students could find the material with proofs. For anyone in our position, gathering and organizing the material required a great deal of work going through preprints and papers and in some cases even finding a proof. We hope that the results of our efforts will be of help to others who plan to learn about complex dynamics and perhaps even lecture. Meanwhile books in the field a. re beginning to appear. The Stony Brook course notes of J. Milnor were particularly welcome and useful. Still we hope that our special emphasis on the analytic side will satisfy a need. This book is a revised and expanded version of notes based on lectures of the first author at UCLA over several \\Vinter Quarters, particularly 1986 and 1990. We owe Chris Bishop a great deal of gratitude for supervising the production of cour...

  14. Dynamics of Tidally Locked, Ultrafast Rotating Atmospheres

    Science.gov (United States)

    Tan, Xianyu; Showman, Adam P.

    2017-10-01

    Tidally locked gas giants, which exhibit a novel regime of day-night thermal forcing and extreme stellar irradiation, are typically in several-day orbits, implying slow rotation and a modest role for rotation in the atmospheric circulation. Nevertheless, there exist a class of gas-giant, highly irradiated objects - brown dwarfs orbiting white dwarfs in extremely tight orbits - whose orbital and hence rotation periods are as short as 1-2 hours. Spitzer phase curves and other observations have already been obtained for this fascinating class of objects, which raise fundamental questions about the role of rotation in controlling the circulation. So far, most modeling studies have investigated rotation periods exceeding a day, as appropriate for typical hot Jupiters. In this work we investigate the dynamics of tidally locked atmospheres in shorter rotation periods down to about two hours. With increasing rotation rate (decreasing rotation period), we show that the width of the equatorial eastward jet decreases, consistent with the narrowing of wave-mean-flow interacting region due to decrease of the equatorial deformation radius. The eastward-shifted equatorial hot spot offset decreases accordingly, and the westward-shifted hot regions poleward of the equatorial jet associated with Rossby gyres become increasingly distinctive. At high latitudes, winds becomes weaker and more geostrophic. The day-night temperature contrast becomes larger due to the stronger influence of rotation. Our simulated atmospheres exhibit small-scale variability, presumably caused by shear instability. Unlike typical hot Jupiters, phase curves of fast-rotating models show an alignment of peak flux to secondary eclipse. Our results have important implications for phase curve observations of brown dwarfs orbiting white dwarfs in ultra tight orbits.

  15. Population dynamics

    Directory of Open Access Journals (Sweden)

    Cooch, E. G.

    2004-06-01

    Full Text Available Increases or decreases in the size of populations over space and time are, arguably, the motivation for much of pure and applied ecological research. The fundamental model for the dynamics of any population is straightforward: the net change over time in the abundance of some population is the simple difference between the number of additions (individuals entering the population minus the number of subtractions (individuals leaving the population. Of course, the precise nature of the pattern and process of these additions and subtractions is often complex, and population biology is often replete with fairly dense mathematical representations of both processes. While there is no doubt that analysis of such abstract descriptions of populations has been of considerable value in advancing our, there has often existed a palpable discomfort when the ‘beautiful math’ is faced with the often ‘ugly realities’ of empirical data. In some cases, this attempted merger is abandoned altogether, because of the paucity of ‘good empirical data’ with which the theoretician can modify and evaluate more conceptually–based models. In some cases, the lack of ‘data’ is more accurately represented as a lack of robust estimates of one or more parameters. It is in this arena that methods developed to analyze multiple encounter data from individually marked organisms has seen perhaps the greatest advances. These methods have rapidly evolved to facilitate not only estimation of one or more vital rates, critical to population modeling and analysis, but also to allow for direct estimation of both the dynamics of populations (e.g., Pradel, 1996, and factors influencing those dynamics (e.g., Nichols et al., 2000. The interconnections between the various vital rates, their estimation, and incorporation into models, was the general subject of our plenary presentation by Hal Caswell (Caswell & Fujiwara, 2004. Caswell notes that although interest has traditionally

  16. Superconductor Dynamics

    CERN Document Server

    Gömöry, F.

    2014-07-17

    Superconductors used in magnet technology could carry extreme currents because of their ability to keep the magnetic flux motionless. The dynamics of the magnetic flux interaction with superconductors is controlled by this property. The cases of electrical transport in a round wire and the magnetization of wires of various shapes (circular, elliptical, plate) in an external magnetic field are analysed. Resistance to the magnetic field penetration means that the field produced by the superconducting magnet is no longer proportional to the supplied current. It also leads to a dissipation of electromagnetic energy. In conductors with unequal transverse dimensions, such as flat cables, the orientation with respect to the magnetic field plays an essential role. A reduction of magnetization currents can be achieved by splitting the core of a superconducting wire into fine filaments; however, new kinds of electrical currents that couple the filaments consequently appear. Basic formulas allowing qualitative analyses ...

  17. Group dynamics.

    Science.gov (United States)

    Scandiffio, A L

    1990-12-01

    Group dynamics play a significant role within any organization, culture, or unit. The important thing to remember with any of these structures is that they are made up of people--people with different ideas, motivations, background, and sometimes different agendas. Most groups, formal or informal, look for a leader in an effort to maintain cohesiveness of the unit. At times, that cultural bond must be developed; once developed, it must be nurtured. There are also times that one of the group no longer finds the culture comfortable and begins to act out behaviorally. It is these times that become trying for the leader as she or he attempts to remain objective when that which was once in the building phase of group cohesiveness starts to fall apart. At all times, the manager must continue to view the employee creating the disturbance as an integral part of the group. It is at this time that it is beneficial to perceive the employee exhibiting problem behaviors as a special employee, as one who needs the benefit of your experience and skills, as one who is still part of the group. It is also during this time that the manager should focus upon her or his own views in the area of power, communication, and the corporate culture of the unit that one has established before attempting to understand another's point of view. Once we understand our own motivation and accept ourselves, it is then that we may move on to offer assistance to another. Once we understand our insecurities recognizing staff dysfunction as a symptom of system dysfunction will not be so threatening to the concept of the manager that we perceive ourselves to be. It takes a secure person to admit that she or he favors staff before deciding to do something to change things. The important thing to know is that it can be done. The favored staff can find a new way of relating to others, the special employee can find new modes of behavior (and even find self-esteem in the process), the group can find new ways

  18. Autonomous Collision-Free Navigation of Microvehicles in Complex and Dynamically Changing Environments.

    Science.gov (United States)

    Li, Tianlong; Chang, Xiaocong; Wu, Zhiguang; Li, Jinxing; Shao, Guangbin; Deng, Xinghong; Qiu, Jianbin; Guo, Bin; Zhang, Guangyu; He, Qiang; Li, Longqiu; Wang, Joseph

    2017-09-26

    Self-propelled micro- and nanoscale robots represent a rapidly emerging and fascinating robotics research area. However, designing autonomous and adaptive control systems for operating micro/nanorobotics in complex and dynamically changing environments, which is a highly demanding feature, is still an unmet challenge. Here we describe a smart microvehicle for precise autonomous navigation in complicated environments and traffic scenarios. The fully autonomous navigation system of the smart microvehicle is composed of a microscope-coupled CCD camera, an artificial intelligence planner, and a magnetic field generator. The microscope-coupled CCD camera provides real-time localization of the chemically powered Janus microsphere vehicle and environmental detection for path planning to generate optimal collision-free routes, while the moving direction of the microrobot toward a reference position is determined by the external electromagnetic torque. Real-time object detection offers adaptive path planning in response to dynamically changing environments. We demonstrate that the autonomous navigation system can guide the vehicle movement in complex patterns, in the presence of dynamically changing obstacles, and in complex biological environments. Such a navigation system for micro/nanoscale vehicles, relying on vision-based close-loop control and path planning, is highly promising for their autonomous operation in complex dynamic settings and unpredictable scenarios expected in a variety of realistic nanoscale scenarios.

  19. Fluid dynamics

    CERN Document Server

    Ruban, Anatoly I

    This is the first book in a four-part series designed to give a comprehensive and coherent description of Fluid Dynamics, starting with chapters on classical theory suitable for an introductory undergraduate lecture course, and then progressing through more advanced material up to the level of modern research in the field. The present Part 1 consists of four chapters. Chapter 1 begins with a discussion of Continuum Hypothesis, which is followed by an introduction to macroscopic functions, the velocity vector, pressure, density, and enthalpy. We then analyse the forces acting inside a fluid, and deduce the Navier-Stokes equations for incompressible and compressible fluids in Cartesian and curvilinear coordinates. In Chapter 2 we study the properties of a number of flows that are presented by the so-called exact solutions of the Navier-Stokes equations, including the Couette flow between two parallel plates, Hagen-Poiseuille flow through a pipe, and Karman flow above an infinite rotating disk. Chapter 3 is d...

  20. Internet dynamics

    Science.gov (United States)

    Lukose, Rajan Mathew

    The World Wide Web and the Internet are rapidly expanding spaces, of great economic and social significance, which offer an opportunity to study many phenomena, often previously inaccessible, on an unprecedented scale and resolution with relative ease. These phenomena are measurable on the scale of tens of millions of users and hundreds of millions of pages. By virtue of nearly complete electronic mediation, it is possible in principle to observe the time and ``spatial'' evolution of nearly all choices and interactions. This cyber-space therefore provides a view into a number of traditional research questions (from many academic disciplines) and creates its own new phenomena accessible for study. Despite its largely self-organized and dynamic nature, a number of robust quantitative regularities are found in the aggregate statistics of interesting and useful quantities. These regularities can be understood with the help of models that draw on ideas from statistical physics as well as other fields such as economics, psychology and decision theory. This thesis develops models that can account for regularities found in the statistics of Internet congestion and user surfing patterns and discusses some practical consequences. practical consequences.

  1. Fast Dynamic Visualizations in Microfluidics Enabled by Fluorescent Carbon Nanodots.

    Science.gov (United States)

    Huang, Yi; Xiao, Lian; An, Tingting; Lim, Wenxiang; Wong, Teckneng; Sun, Handong

    2017-09-01

    Microfluidic systems have become a superior platform for explorations of fascinating fluidic physics at microscale as well as applications in biomedical devices, chemical reactions, drug delivery, etc. Exploitations of this platform are built upon the fundamental techniques of flow visualizations. However, the currently employed fluorescent materials for microfluidic visualization are far from satisfaction, which severely hinders their widespread applications. Here fluorescent carbon nanodots are documented as a game-changer, applicable in versatile fluidic environment for the visualization in microfluidics with unprecedented advantages. One of the fastest fluorescent imaging speeds up to 2500 frames per second under a normal contionous wave (CW) laser line is achieved by adopting carbon nanodots in microfluidics. Besides better visualizations of the fluid or interface, fluorescent carbon nanodots-based microparticles enable quantitative studies of high speed dynamics in fluids at microscale with a more than 90% lower cost, which is inaccessible by traditionally adopted fluorescent dye based seeding particles. The findings hold profound influences to microfluidic investigations and may even lead to revolutionary changes to the relevant industries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Dinosaur dynamics in the Jurassic Era

    Science.gov (United States)

    Lee, Scott

    2010-04-01

    Dinosaurs were fascinating animals and elicit much excitement in the classroom. Analysis of fossilized dinosaur trackways permits one to estimate the locomotion speeds and accelerations of these extinct beasts. Such analysis allows one to apply Newton's laws of motion to examples from the Jurassic Era.

  3. Population Dynamics of Banteng, Buffalo and Deer in Bekol Savannah, Baluran National Park

    Directory of Open Access Journals (Sweden)

    SUHADI

    2009-07-01

    Full Text Available Baluran National Park give contribution at regional development to draw tourist and fascination provided is savannah in area. Savannah circumstance, forest, landscape, climate, vegetation and wild animal is represent experienced attraction. Research method use population dynamics perception of banteng, buffalo and deer in savannah of Bekol year 2004 and year 2005 as primary data, while secondary data year population dynamics 2003, 2004, and year 2005 outside savannah of Bekol, year population dynamics 2003 in savannah of Bekol. Secondary data obtained from daily report of Controller ecosystem Forest Worker animal discovery Baluran National Park from Section Bekol. Research location of outside savannah Bekol were Balanan, Perengan, Bitakol, Karangtekok, Pandean, Pondok jaran, Bama, Curah uling, Gunung Montor, Lempuyang, Bilik, Batangan, Labuhan Merak, Kramat, Semiang, Sirokoh, Lemah bang, Gunung Krasak, and Glengseran. The populations of banteng and buffalo in the savannah is unstable compared to the populations of them outside Bekol savannah. The populations of banteng and buffalo in Bekol savannah decrease, whereas the populations of them outside the Bekol savannah increase. The population of deer in Bekol savannah in 2004 is better than population of 2003, 2005, and 2006, whereas the population of deer outside Bekol savannah in 2006 increase significantly. The populations of banteng, buffalo, and deer decrease from year to year, in which the reductions of banteng and buffalo populations are obviously significant.

  4. Pivotal roles of phyllosphere microorganisms at the interface between plant functioning and atmospheric trace gas dynamics

    Science.gov (United States)

    Bringel, Françoise; Couée, Ivan

    2015-01-01

    The phyllosphere, which lato sensu consists of the aerial parts of plants, and therefore primarily, of the set of photosynthetic leaves, is one of the most prevalent microbial habitats on earth. Phyllosphere microbiota are related to original and specific processes at the interface between plants, microorganisms and the atmosphere. Recent –omics studies have opened fascinating opportunities for characterizing the spatio-temporal structure of phyllosphere microbial communities in relation with structural, functional, and ecological properties of host plants, and with physico-chemical properties of the environment, such as climate dynamics and trace gas composition of the surrounding atmosphere. This review will analyze recent advances, especially those resulting from environmental genomics, and how this novel knowledge has revealed the extent of the ecosystemic impact of the phyllosphere at the interface between plants and atmosphere. Highlights • The phyllosphere is one of the most prevalent microbial habitats on earth. • Phyllosphere microbiota colonize extreme, stressful, and changing environments. • Plants, phyllosphere microbiota and the atmosphere present a dynamic continuum. • Phyllosphere microbiota interact with the dynamics of volatile organic compounds and atmospheric trace gasses. PMID:26052316

  5. Geophysical Fluid Dynamics Laboratory Open Days at the Woods Hole Oceanographic Institution

    Science.gov (United States)

    Hyatt, Jason; Cenedese, Claudia; Jensen, Anders

    2015-11-01

    This event was hosted for one week for two consecutive years in 2013 and 2014. It targeted postdocs, graduate students, K-12 students and local community participation. The Geophysical Fluid Dynamics Laboratory at the Woods Hole Oceanographic Institution hosted 10 hands-on demonstrations and displays, with something for all ages, to share the excitement of fluid mechanics and oceanography. The demonstrations/experiments spanned as many fluid mechanics problems as possible in all fields of oceanography and gave insight into using fluids laboratory experiments as a research tool. The chosen experiments were `simple' yet exciting for a 6 year old child, a high school student, a graduate student, and a postdoctoral fellow from different disciplines within oceanography. The laboratory is a perfect environment in which to create excitement and stimulate curiosity. Even what we consider `simple' experiments can fascinate and generate interesting questions from both a 6 year old child and a physics professor. How does an avalanche happen? How does a bath tub vortex form? What happens to waves when they break? How does a hurricane move? Hands-on activities in the fluid dynamics laboratory helped students of all ages in answering these and other intriguing questions. The laboratory experiments/demonstrations were accompanied by `live' videos to assist in the interpretation of the demonstrations. Posters illustrated the oceanographic/scientific applicability and the location on Earth where the dynamics in the experiments occur. Support was given by the WHOI Doherty Chair in Education.

  6. Fundamentals of structural dynamics

    CERN Document Server

    Craig, Roy R

    2006-01-01

    From theory and fundamentals to the latest advances in computational and experimental modal analysis, this is the definitive, updated reference on structural dynamics.This edition updates Professor Craig's classic introduction to structural dynamics, which has been an invaluable resource for practicing engineers and a textbook for undergraduate and graduate courses in vibrations and/or structural dynamics. Along with comprehensive coverage of structural dynamics fundamentals, finite-element-based computational methods, and dynamic testing methods, this Second Edition includes new and e

  7. Identifying consumer-resource population dynamics using paleoecological data.

    Science.gov (United States)

    Einarsson, Árni; Hauptfleisch, Ulf; Leavitt, Peter R; Ives, Anthony R

    2016-02-01

    Ecologists have long been fascinated by cyclic population fluctuations, because they suggest strong interactions between exploiter and victim species. Nonetheless, even for populations showing high-amplitude fluctuations, it is often hard to identify which species are the key drivers of the dynamics, because data are generally only available for a single species. Here, we use a paleoecological approach to investigate fluctuations in the midge population in Lake Mývatn, Iceland, which ranges over several orders of magnitude in irregular, multigeneration cycles. Previous circumstantial evidence points to consumer-resource interactions between midges and their primary food, diatoms, as the cause of these high-amplitude fluctuations. Using a pair of sediment cores from the lake, we reconstructed 26 years of dynamics of midges using egg remains and of algal groups using diagnostic pigments. We analyzed these data using statistical methods that account for both the autocorrelated nature of paleoecological data and measurement error caused by the mixing of sediment layers. The analyses revealed a signature of consumer-resource interactions in the fluctuations of midges and diatoms: diatom abundance (as inferred from biomarker pigment diatoxanthin) increased when midge abundance was low, and midge abundance (inferred from egg capsules) decreased when diatom abundance was low. Similar patterns were not found for pigments characterizing the other dominant primary producer group in the lake (cyanobacteria), subdominant algae (cryptophytes), or ubiquitous but chemically unstable biomarkers of total algal abundance (chlorophyll a); however, a significant but weaker pattern was found for the chemically stable indicator of total algal populations (β-carotene) to which diatoms are the dominant contributor. These analyses provide the first paleoecological evaluation of specific trophic interactions underlying high amplitude population fluctuations in lakes.

  8. Solar Dynamics Observatory

    Data.gov (United States)

    National Aeronautics and Space Administration — A searchable database of all Solar Dynamics Observatory data including EUV, magnetograms, visible light and X-ray. SDO: The Solar Dynamics Observatory is the first...

  9. Universality in network dynamics.

    Science.gov (United States)

    Barzel, Baruch; Barabási, Albert-László

    2013-01-01

    Despite significant advances in characterizing the structural properties of complex networks, a mathematical framework that uncovers the universal properties of the interplay between the topology and the dynamics of complex systems continues to elude us. Here we develop a self-consistent theory of dynamical perturbations in complex systems, allowing us to systematically separate the contribution of the network topology and dynamics. The formalism covers a broad range of steady-state dynamical processes and offers testable predictions regarding the system's response to perturbations and the development of correlations. It predicts several distinct universality classes whose characteristics can be derived directly from the continuum equation governing the system's dynamics and which are validated on several canonical network-based dynamical systems, from biochemical dynamics to epidemic spreading. Finally, we collect experimental data pertaining to social and biological systems, demonstrating that we can accurately uncover their universality class even in the absence of an appropriate continuum theory that governs the system's dynamics.

  10. Adaptive dynamical networks

    Science.gov (United States)

    Maslennikov, O. V.; Nekorkin, V. I.

    2017-10-01

    Dynamical networks are systems of active elements (nodes) interacting with each other through links. Examples are power grids, neural structures, coupled chemical oscillators, and communications networks, all of which are characterized by a networked structure and intrinsic dynamics of their interacting components. If the coupling structure of a dynamical network can change over time due to nodal dynamics, then such a system is called an adaptive dynamical network. The term ‘adaptive’ implies that the coupling topology can be rewired; the term ‘dynamical’ implies the presence of internal node and link dynamics. The main results of research on adaptive dynamical networks are reviewed. Key notions and definitions of the theory of complex networks are given, and major collective effects that emerge in adaptive dynamical networks are described.

  11. Intramolecular and nonlinear dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Davis, M.J. [Argonne National Laboratory, IL (United States)

    1993-12-01

    Research in this program focuses on three interconnected areas. The first involves the study of intramolecular dynamics, particularly of highly excited systems. The second area involves the use of nonlinear dynamics as a tool for the study of molecular dynamics and complex kinetics. The third area is the study of the classical/quantum correspondence for highly excited systems, particularly systems exhibiting classical chaos.

  12. The dynamics of scaffolding

    NARCIS (Netherlands)

    Van Geert, P. L. C.; Steenbeek, H.W.

    2005-01-01

    In this article we have reinterpreted a relatively standard definition of scaffolding in the context of dynamic systems theory. Our main point is that scaffolding cannot be understood outside the context of a dynamic approach of learning and (formal or informal) teaching. We provide a dynamic

  13. Dynamic planar embeddings of dynamic graphs

    DEFF Research Database (Denmark)

    Holm, Jacob; Rotenberg, Eva

    2017-01-01

    We present an algorithm to support the dynamic embedding in the plane of a dynamic graph. An edge can be inserted across a face between two vertices on the face boundary (we call such a vertex pair linkable), and edges can be deleted. The planar embedding can also be changed locally by flipping...... query, one-flip- linkable(u,v) providing a suggestion for a flip that will make them linkable if one exists. We support all updates and queries in O(log 2 n) time. Our time bounds match those of Italiano et al. for a static (flipless) embedding of a dynamic graph. Our new algorithm is simpler...

  14. Dynamic planar embeddings of dynamic graphs

    DEFF Research Database (Denmark)

    Holm, Jacob; Rotenberg, Eva

    2015-01-01

    We present an algorithm to support the dynamic embedding in the plane of a dynamic graph. An edge can be inserted across a face between two vertices on the boundary (we call such a vertex pair linkable), and edges can be deleted. The planar embedding can also be changed locally by flipping......-flip-linkable(u, v) providing a suggestion for a flip that will make them linkable if one exists. We will support all updates and queries in O(log2 n) time. Our time bounds match those of Italiano et al. for a static (flipless) embedding of a dynamic graph. Our new algorithm is simpler, exploiting...

  15. Explicit Dynamic DDA Method considering Dynamic Contact Force

    National Research Council Canada - National Science Library

    Jian Zhao; Ming Xiao; Juntao Chen; Dongdong Li

    2016-01-01

      This paper proposes an explicit dynamic DDA method considering dynamic contact force, which aims at solving the problems of low efficiency of dynamic contact detection and the simulation of dynamic...

  16. OTTO MOTOR DYNAMICS

    Directory of Open Access Journals (Sweden)

    Florian Ion Tiberiu Petrescu

    2016-09-01

    Full Text Available Otto engine dynamics are similar in almost all common internal combustion engines. We can speak so about dynamics of engines: Lenoir, Otto, and Diesel. The dynamic presented model is simple and original. The first thing necessary in the calculation of Otto engine dynamics, is to determine the inertial mass reduced at the piston. It uses then the Lagrange equation. The dynamic equation of motion of the piston, obtained by integrating the Lagrange equation, takes a new form. It presents a new relation which determines the elastic constant of the crank shaft, k. The moment of inertia J1 can be determined with an original relation, as well.

  17. Unusual stability of messenger RNA in snake venom reveals gene expression dynamics of venom replenishment.

    Directory of Open Access Journals (Sweden)

    Rachel B Currier

    Full Text Available Venom is a critical evolutionary innovation enabling venomous snakes to become successful limbless predators; it is therefore vital that venomous snakes possess a highly efficient venom production and delivery system to maintain their predatory arsenal. Here, we exploit the unusual stability of messenger RNA in venom to conduct, for the first time, quantitative PCR to characterise the dynamics of gene expression of newly synthesised venom proteins following venom depletion. Quantitative PCR directly from venom enables real-time dynamic studies of gene expression in the same animals because it circumvents the conventional requirement to sacrifice snakes to extract mRNA from dissected venom glands. Using qPCR and proteomic analysis, we show that gene expression and protein re-synthesis triggered by venom expulsion peaks between days 3-7 of the cycle of venom replenishment, with different protein families expressed in parallel. We demonstrate that venom re-synthesis occurs very rapidly following depletion of venom stores, presumably to ensure venomous snakes retain their ability to efficiently predate and remain defended from predators. The stability of mRNA in venom is biologically fascinating, and could significantly empower venom research by expanding opportunities to produce transcriptomes from historical venom stocks and rare or endangered venomous species, for new therapeutic, diagnostic and evolutionary studies.

  18. Reaction Profiles and Molecular Dynamics Simulations of Cyanide Radical Reactions Relevant to Titan's Atmosphere

    Science.gov (United States)

    Trinidad Pérez-Rivera, Danilo; Romani, Paul N.; Lopez-Encarnacion, Juan Manuel

    2016-10-01

    Titan's atmosphere is arguably the atmosphere of greatest interest that we have an abundance of data for from both ground based and spacecraft observations. As we have learned more about Titan's atmospheric composition, the presence of pre-biotic molecules in its atmosphere has generated more and more fascination about the photochemical process and pathways it its atmosphere. Our computational laboratory has been extensively working throughout the past year characterizing nitrile synthesis reactions, making significant progress on the energetics and dynamics of the reactions of .CN with the hydrocarbons acetylene (C2H2), propylene (CH3CCH), and benzene (C6H6), developing a clear picture of the mechanistic aspects through which these three reactions proceed. Specifically, first principles calculations of the reaction profiles and molecular dynamics studies for gas-phase reactions of .CN and C2H2, .CN and CH3CCH, and .CN and C6H6 have been carried out. A very accurate determination of potential energy surfaces of these reactions will allow us to compute the reaction rates which are indispensable for photochemical modeling of Titan's atmosphere.The work at University of Puerto Rico at Cayey was supported by Puerto Rico NASA EPSCoR IDEAS-ER program (2015-2016) and DTPR was sponsored by the Puerto Rico NASA Space Grant Consortium Fellowship. *E-mail: juan.lopez15@upr.edu

  19. A Hierarchy of Dynamic Equilibria and a View of a Fly's Equilibrium Reflex

    Science.gov (United States)

    Wang, Z. Jane

    Understanding structures within a structure is a topic that has fascinated Leo throughout his life, and we are now benefiting from his fundamental insights when we think about living organisms. A living organism is far from statistical equilibrium and it does not have a single critical parameter. Nevertheless, each organism has a hierarchical structure within itself. Recently, asking how often a fly must sense its orientation in order to balance in air has led us to suggest one of the fly's 17 steering muscles, the first basalar muscle, is responsible for maintaining flight stability. Here I suggest that the chain of events associated with flight equilibrium reflex can be viewed as a succession of local linear transformation about a set of dynamic equilibria. Each of the functionally different parts, the sensors, motor neurons, muscles, wing-hinges, flapping wings, and the thorax, operates near its own dynamic equilibrium, often close to the boundary between stability and instability. Locomotion rises as an organism responds to a small perturbation from these equilibria. Kadanoff session.

  20. Variable Dynamic Testbed Vehicle: Dynamics Analysis

    Science.gov (United States)

    Lee, A. Y.; Le, N. T.; Marriott, A. T.

    1997-01-01

    The Variable Dynamic Testbed Vehicle (VDTV) concept has been proposed as a tool to evaluate collision avoidance systems and to perform driving-related human factors research. The goal of this study is to analytically investigate to what extent a VDTV with adjustable front and rear anti-roll bar stiffnesses, programmable damping rates, and four-wheel-steering can emulate the lateral dynamics of a broad range of passenger vehicles.

  1. News Education: Physics Education Networks meeting has global scale Competition: Competition seeks the next Brian Cox Experiment: New measurement of neutrino time-of-flight consistent with the speed of light Event: A day for all those who teach physics Conference: Students attend first Anglo-Japanese international science conference Celebration: Will 2015 be the 'Year of Light'? Teachers: Challenging our intuition in spectacular fashion: the fascinating world of quantum physics awaits Research: Science sharpens up sport Learning: Kittinger and Baumgartner: on a mission to the edge of space International: London International Youth Science Forum calls for leading young scientists Competition: Physics paralympian challenge needs inquisitive, analytical, artistic and eloquent pupils Forthcoming events

    Science.gov (United States)

    2012-05-01

    Education: Physics Education Networks meeting has global scale Competition: Competition seeks the next Brian Cox Experiment: New measurement of neutrino time-of-flight consistent with the speed of light Event: A day for all those who teach physics Conference: Students attend first Anglo-Japanese international science conference Celebration: Will 2015 be the 'Year of Light'? Teachers: Challenging our intuition in spectacular fashion: the fascinating world of quantum physics awaits Research: Science sharpens up sport Learning: Kittinger and Baumgartner: on a mission to the edge of space International: London International Youth Science Forum calls for leading young scientists Competition: Physics paralympian challenge needs inquisitive, analytical, artistic and eloquent pupils Forthcoming events

  2. Deformed Materials: Towards a Theory of Materials Morphology Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Sethna, James P [Laboratory of Atomic and Solid State Physics, Cornell University

    2017-06-28

    This grant supported work on the response of crystals to external stress. Our primary work described how disordered structural materials break in two (statistical models of fracture in disordered materials), studied models of deformation bursts (avalanches) that mediate deformation on the microscale, and developed continuum dislocation dynamics models for plastic deformation (as when scooping ice cream bends a spoon, Fig. 9). Glass is brittle -- it breaks with almost atomically smooth fracture surfaces. Many metals are ductile -- when they break, the fracture surface is locally sheared and stretched, and it is this damage that makes them hard to break. Bone and seashells are made of brittle material, but they are strong because they are disordered -- lots of little cracks form as they are sheared and near the fracture surface, diluting the external force. We have studied materials like bone and seashells using simulations, mathematical tools, and statistical mechanics models from physics. In particular, we studied the extreme values of fracture strengths (how likely will a beam in a bridge break far below its design strength), and found that the traditional engineering tools could be improved greatly. We also studied fascinating crackling-noise precursors -- systems which formed microcracks of a broad range of sizes before they broke. Ductile metals under stress undergo irreversible plastic deformation -- the planes of atoms must slide across one another (through the motion of dislocations) to change the overall shape in response to the external force. Microscopically, the dislocations in crystals move in bursts of a broad range of sizes (termed 'avalanches' in the statistical mechanics community, whose motion is deemed 'crackling noise'). In this grant period, we resolved a longstanding mystery about the average shape of avalanches of fixed duration (using tools related to an emergent scale invariance), we developed the fundamental theory

  3. What can we learn from the dynamics of entanglement and quantum discord in the Tavis-Cummings model?

    Science.gov (United States)

    Restrepo, Juliana; Rodriguez, Boris A.

    We revisit the problem of the dynamics of quantum correlations in the exact Tavis-Cummings model. We show that many of the dynamical features of quantum discord attributed to dissipation are already present in the exact framework and are due to the well known non-linearities in the model and to the choice of initial conditions. Through a comprehensive analysis, supported by explicit analytical calculations, we find that the dynamics of entanglement and quantum discord are far from being trivial or intuitive. In this context, we find states that are indistinguishable from the point of view of entanglement and distinguishable from the point of view of quantum discord, states where the two quantifiers give opposite information and states where they give roughly the same information about correlations at a certain time. Depending on the initial conditions, this model exhibits a fascinating range of phenomena that can be used for experimental purposes such as: Robust states against change of manifold or dissipation, tunable entanglement states and states with a counterintuitive sudden birth as the number of photons increase. We furthermore propose an experiment called quantum discord gates where discord is zero or non-zero depending on the number of photons. This work was supported by the Vicerrectoria de Investigacion of the Universidad Antonio Narino, Colombia under Project Number 20141031 and by the Departamento Administrativo de Ciencia, Tecnologia e Innovacion (COLCIENCIAS) of Colombia under Grant Number.

  4. Dynamical systems theory for music dynamics.

    Science.gov (United States)

    Boon, Jean Pierre; Decroly, Olivier

    1995-09-01

    We show that, when music pieces are cast in the form of time series of pitch variations, the concepts and tools of dynamical systems theory can be applied to the analysis of temporal dynamics in music. (i) Phase space portraits are constructed from the time series wherefrom the dimensionality is evaluated as a measure of the global dynamics of each piece. (ii) Spectral analysis of the time series yields power spectra ( approximately f(-nu)) close to red noise (nu approximately 2) in the low frequency range. (iii) We define an information entropy which provides a measure of the local dynamics in the musical piece; the entropy can be interpreted as an evaluation of the degree of complexity in the music, but there is no evidence of an analytical relation between local and global dynamics. These findings are based on computations performed on eighty sequences sampled in the music literature from the 18th to the 20th century. (c) 1995 American Institute of Physics.

  5. Dynamic Boiler Performance

    DEFF Research Database (Denmark)

    Sørensen, Kim

    Traditionally, boilers have been designed mainly focussing on the static operation of the plant. The dynamic capability has been given lower priority and the analysis has typically been limited to assuring that the plant was not over-stressed due to large temperature gradients. New possibilities...... for buying and selling energy has increased the focus on the dynamic operation capability, efciency, emissions etc. For optimizing the design of boilers for dynamic operation a quantication of the dynamic capability is needed. A framework for optimizing design of boilers for dynamic operation has been...... developed. Analyzing boilers for dynamic operation gives rise to a number of opposing aims: shrinking and swelling, steam quality, stress levels, control system/philosophy, pressurization etc. Common for these opposing aims is that an optimum can be found for selected operation conditions. The framework has...

  6. Dynamic airfoil stall investigations

    Science.gov (United States)

    Platzer, M. F.; Chandrasekhara, M. S.; Ekaterinaris, J. A.; Carr, L. W.

    1992-01-01

    Experimental and computational investigations of the dynamic stall phenomenon continue to attract the attention of various research groups in the major aeronautical research laboratories. There are two reasons for this continued research interest. First, the occurrence of dynamic stall on the retreating blade of helicopters imposes a severe performance limitation and thus suggests to search for ways to delay the onset of dynamic stall. Second, the lift enhancement prior to dynamic stall presents an opportunity to achieve enhanced maneuverability of fighter aircraft. A description of the major parameters affecting dynamic stall and lift and an evaluation of research efforts prior to 1988 has been given by Carr. In this paper the authors' recent progress in the development of experimental and computational methods to analyze the dynamic stall phenomena occurring on NACA 0112 airfoils is reviewed. First, the major experimental and computational approaches and results are summarized. This is followed by an assessment of our results and an outlook toward the future.

  7. Double dynamic scaling in human communication dynamics

    Science.gov (United States)

    Wang, Shengfeng; Feng, Xin; Wu, Ye; Xiao, Jinhua

    2017-05-01

    In the last decades, human behavior has been deeply understanding owing to the huge quantities data of human behavior available for study. The main finding in human dynamics shows that temporal processes consist of high-activity bursty intervals alternating with long low-activity periods. A model, assuming the initiator of bursty follow a Poisson process, is widely used in the modeling of human behavior. Here, we provide further evidence for the hypothesis that different bursty intervals are independent. Furthermore, we introduce a special threshold to quantitatively distinguish the time scales of complex dynamics based on the hypothesis. Our results suggest that human communication behavior is a composite process of double dynamics with midrange memory length. The method for calculating memory length would enhance the performance of many sequence-dependent systems, such as server operation and topic identification.

  8. Topological dynamics on hyperspaces

    Directory of Open Access Journals (Sweden)

    Puneet Sharma

    2010-04-01

    Full Text Available In this paper we wish to relate the dynamics of the base map to the dynamics of the induced map. In the process, we obtain conditions on the endowed hyperspace topology under which the chaotic behaviour of the map on the base space is inherited by the induced map on the hyperspace. Several of the known results come up as corollaries to our results. We also discuss some metric related dynamical properties on the hyperspace that cannot be deduced for the base dynamics.

  9. Dynamics of machinery

    CERN Document Server

    Dresig, Hans

    2010-01-01

    Dynamic loads and disturbing oscillations increase with higher speed of the machines and more lightweight constructions. Industrial safety standards require better oscillation reduction and noise control. The book by Dresig/Holzweissig deals with these topics. It presents the classical areas of modeling, dynamics of rigid bodies, balancing, torsional and bending vibrations, problems of vibration isolation and the dynamic behavior of complex vibrating systems. Typical dynamic effects, i.e., the gyroscopic effect, the damping of oscillations, resonances of k-th order, subharmonic and nonlinear f

  10. Essential dynamics and relativity

    CERN Document Server

    O'Donnell, Peter J

    2014-01-01

    Essential Dynamics & Relativity provides students with an introduction to the core aspects of dynamics and special relativity. The author reiterates important ideas and terms throughout and covers concepts that are often missing from other textbooks at this level. He also places each topic within the wider constructs of the theory, without jumping from topic to topic to illustrate a point.The first section of the book focuses on dynamics, discussing the basic aspects of single particle motion and analyzing the motion of multi-particle systems. The book also explains the dynamical behavior of b

  11. DYNAMICS OF SOCIAL INFLUENCE.

    Science.gov (United States)

    SOCIAL PSYCHOLOGY , ATTITUDES( PSYCHOLOGY )), (*ATTITUDES( PSYCHOLOGY ), SOCIAL PSYCHOLOGY ), GROUP DYNAMICS, BEHAVIOR, PERFORMANCE(HUMAN), SOCIAL...COMMUNICATION, BIBLIOGRAPHIES, MALES, FEMALES, PERFORMANCE(HUMAN), SOCIOMETRICS, PSYCHOLOGICAL TESTS

  12. Dynamic systemic resolution.

    Science.gov (United States)

    Sakulsombat, Morakot; Zhang, Yan; Ramström, Olof

    2012-01-01

    Dynamic Systemic Resolution is a powerful technique for selecting optimal constituents from dynamic systems by applying selection pressures, either externally by addition of target entities, or internally within the system constraints. This concept is a subset of Constitutional Dynamic Chemistry, and the dynamic systems are generally based on reversible covalent interactions between a range of components where the systems are maintained under thermodynamic control. In the present chapter, the concept will be described in detail, and a range of examples will be given for both selection classes. For external pressure generation, target enzymes, in aqueous and/or organic solution, have been used to demonstrate the resolution processes. In a first example, a dynamic transthiolesterification system was generated in aqueous solution at neutral pH, and resolved by hydrolysis using serine hydrolases (cholinesterases). In organic solution, lipase-catalyzed acylation was chosen to demonstrate asymmetric resolution in different dynamic systems, generating chiral ester and amide structures. By use of such biocatalysts, the optimal constituents were selectively chosen and amplified from the dynamic systems in one-pot processes. In internal selection pressure resolution, self-transformation and crystallization-induced diastereomeric resolution have been successfully used to challenge dynamic systems. The technique was, for example, used to identify the best diastereomeric substrate from a large and varied dynamic system in a single resolution reaction.

  13. Nonlinear dynamics and complexity

    CERN Document Server

    Luo, Albert; Fu, Xilin

    2014-01-01

    This important collection presents recent advances in nonlinear dynamics including analytical solutions, chaos in Hamiltonian systems, time-delay, uncertainty, and bio-network dynamics. Nonlinear Dynamics and Complexity equips readers to appreciate this increasingly main-stream approach to understanding complex phenomena in nonlinear systems as they are examined in a broad array of disciplines. The book facilitates a better understanding of the mechanisms and phenomena in nonlinear dynamics and develops the corresponding mathematical theory to apply nonlinear design to practical engineering.

  14. Dynamical holographic QCD model

    Directory of Open Access Journals (Sweden)

    Li Danning

    2014-01-01

    Full Text Available We develop a dynamical holographic QCD model, which resembles the renormalization group from ultraviolet (UV to infrared (IR. The dynamical holographic model is constructed in the graviton-dilaton-scalar framework with the dilaton background field Φ and scalar field X responsible for the gluodynamics and chiral dynamics, respectively. We summarize the results on hadron spectra, QCD phase transition and transport properties including the jet quenching parameter and the shear/bulk viscosity in the framework of the dynamical holographic QCD model.

  15. Dynamic power flow controllers

    Science.gov (United States)

    Divan, Deepakraj M.; Prasai, Anish

    2017-03-07

    Dynamic power flow controllers are provided. A dynamic power flow controller may comprise a transformer and a power converter. The power converter is subject to low voltage stresses and not floated at line voltage. In addition, the power converter is rated at a fraction of the total power controlled. A dynamic power flow controller controls both the real and the reactive power flow between two AC sources having the same frequency. A dynamic power flow controller inserts a voltage with controllable magnitude and phase between two AC sources; thereby effecting control of active and reactive power flows between two AC sources.

  16. Introduction to dynamic programming

    CERN Document Server

    Cooper, Leon; Rodin, E Y

    1981-01-01

    Introduction to Dynamic Programming provides information pertinent to the fundamental aspects of dynamic programming. This book considers problems that can be quantitatively formulated and deals with mathematical models of situations or phenomena that exists in the real world.Organized into 10 chapters, this book begins with an overview of the fundamental components of any mathematical optimization model. This text then presents the details of the application of dynamic programming to variational problems. Other chapters consider the application of dynamic programming to inventory theory, Mark

  17. Structural Dynamics Laboratory (SDL)

    Data.gov (United States)

    Federal Laboratory Consortium — Structural dynamic testing is performed to verify the survivability of a component or assembly when exposed to vibration stress screening, or a controlled simulation...

  18. Dynamical Systems Conference

    CERN Document Server

    Gils, S; Hoveijn, I; Takens, F; Nonlinear Dynamical Systems and Chaos

    1996-01-01

    Symmetries in dynamical systems, "KAM theory and other perturbation theories", "Infinite dimensional systems", "Time series analysis" and "Numerical continuation and bifurcation analysis" were the main topics of the December 1995 Dynamical Systems Conference held in Groningen in honour of Johann Bernoulli. They now form the core of this work which seeks to present the state of the art in various branches of the theory of dynamical systems. A number of articles have a survey character whereas others deal with recent results in current research. It contains interesting material for all members of the dynamical systems community, ranging from geometric and analytic aspects from a mathematical point of view to applications in various sciences.

  19. The Use of the Dynamic Magnification Factor in the Dynamic ...

    African Journals Online (AJOL)

    This paper examined the use of the dynamic magnification factor in the analysis of framed structures. It is a method of practice in dynamic analysis of structures to magnify static response by a dynamic magnification factor in order to obtain the equivalent dynamic response. This method has been applied to the dynamic ...

  20. Dynamic normal forms and dynamic characteristic polynomial

    DEFF Research Database (Denmark)

    Frandsen, Gudmund Skovbjerg; Sankowski, Piotr

    2011-01-01

    We present the first fully dynamic algorithm for computing the characteristic polynomial of a matrix. In the generic symmetric case, our algorithm supports rank-one updates in O(n2logn) randomized time and queries in constant time, whereas in the general case the algorithm works in O(n2klogn...

  1. Dynamic covalent surfactants

    NARCIS (Netherlands)

    Minkenberg, C.B.

    2012-01-01

    In this thesis the development of surfactant aggregates with fast exchange dynamics between the aggregated and non-aggregated state is described. Dynamic surfactant exchange plays an important role in natural systems, for instance in cell signaling, cell division, and uptake and release of cargo.

  2. Understanding Wheel Dynamics.

    Science.gov (United States)

    Proffitt, Dennis R.; And Others

    1990-01-01

    In 5 experiments, assessments were made of subjects' understandings of the dynamics of wheels. The subjects--111 undergraduates and 19 high school physics teachers--made highly erroneous dynamical judgments about this commonplace event, both in explicit problem-solving contexts and when viewing ongoing events. Findings are related to accounts of…

  3. Black Hole Dynamic Potentials

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... In the following paper, certain black hole dynamic potentials have been developed definitively on the lines of classical thermodynamics. These potentials have been refined in view of the small differences in the equations of the laws of black hole dynamics as given by Bekenstein and those of ...

  4. Friction and nonlinear dynamics

    OpenAIRE

    Manini, N.; Braun, O. M.; Tosatti, E.; Guerra, R.; Vanossi, A.

    2016-01-01

    The nonlinear dynamics associated with sliding friction forms a broad interdisciplinary research field that involves complex dynamical processes and patterns covering a broad range of time and length scales. Progress in experimental techniques and computational resources has stimulated the development of more refined and accurate mathematical and numerical models, capable of capturing many of the essentially nonlinear phenomena involved in friction.

  5. Dynamic epistemic modelling

    NARCIS (Netherlands)

    D.J.N. van Eijck (Jan)

    2004-01-01

    textabstractThis paper introduces DEMO, a Dynamic Epistemic Modelling tool. DEMO llows modelling epistemic updates, graphical display of update results, graphical display of action models, formula evaluation in epistemic models, translation of dynamic epistemic formulas to PDL formulas, and so on.

  6. Structural Dynamics, Vol. 9

    DEFF Research Database (Denmark)

    Nielsen, Søren R.K.

    This book has been prepared for the course on Computational Dynamics given at the 8th semester at the structural program in civil engineering at Aalborg University.......This book has been prepared for the course on Computational Dynamics given at the 8th semester at the structural program in civil engineering at Aalborg University....

  7. Advances in soil dynamics

    DEFF Research Database (Denmark)

    Advances in Soil Dynamics, Volume 3, represents the culmination of the work undertaken by the Advances in Soil Dynamics Monograph Committee, PM-45-01, about 15 years ago to summarize important developments in this field over the last 35 years. When this project was initiated, the main goal was to...

  8. Visualizing Dynamic Memory Allocations

    NARCIS (Netherlands)

    Moreta, Sergio; Telea, Alexandru

    2007-01-01

    We present a visualization tool for dynamic memory allocation information obtained from instrumenting the runtime allocator used by C programs. The goal of the presented visualization techniques is to convey insight in the dynamic behavior of the allocator. The purpose is to help the allocator

  9. Dynamic Latent Classification Model

    DEFF Research Database (Denmark)

    Zhong, Shengtong; Martínez, Ana M.; Nielsen, Thomas Dyhre

    as possible. Motivated by this problem setting, we propose a generative model for dynamic classification in continuous domains. At each time point the model can be seen as combining a naive Bayes model with a mixture of factor analyzers (FA). The latent variables of the FA are used to capture the dynamics...

  10. Dynamics on the Circle

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 11. Dynamics on the Circle - Interval Dynamics and Rotation Number. Siddhartha Gadgil. General Article Volume 8 Issue 11 November ... Author Affiliations. Siddhartha Gadgil1. Stat-Math Unit Indian Statistical Institute Bangalore 560 064, India.

  11. Dynamic defense workshop :

    Energy Technology Data Exchange (ETDEWEB)

    Crosby, Sean Michael; Doak, Justin E.; Haas, Jason Juedes.; Helinski, Ryan; Lamb, Christopher C.

    2013-02-01

    On September 5th and 6th, 2012, the Dynamic Defense Workshop: From Research to Practice brought together researchers from academia, industry, and Sandia with the goals of increasing collaboration between Sandia National Laboratories and external organizations, de ning and un- derstanding dynamic, or moving target, defense concepts and directions, and gaining a greater understanding of the state of the art for dynamic defense. Through the workshop, we broadened and re ned our de nition and understanding, identi ed new approaches to inherent challenges, and de ned principles of dynamic defense. Half of the workshop was devoted to presentations of current state-of-the-art work. Presentation topics included areas such as the failure of current defenses, threats, techniques, goals of dynamic defense, theory, foundations of dynamic defense, future directions and open research questions related to dynamic defense. The remainder of the workshop was discussion, which was broken down into sessions on de ning challenges, applications to host or mobile environments, applications to enterprise network environments, exploring research and operational taxonomies, and determining how to apply scienti c rigor to and investigating the eld of dynamic defense.

  12. Dynamic reservoir well interaction

    NARCIS (Netherlands)

    Sturm, W.L.; Belfroid, S.P.C.; Wolfswinkel, O. van; Peters, M.C.A.M.; Verhelst, F.J.P.C.M.

    2004-01-01

    In order to develop smart well control systems for unstable oil wells, realistic modeling of the dynamics of the well is essential. Most dynamic well models use a semi-steady state inflow model to describe the inflow of oil and gas from the reservoir. On the other hand, reservoir models use steady

  13. Nonlinear dynamics of structures

    CERN Document Server

    Oller, Sergio

    2014-01-01

    This book lays the foundation of knowledge that will allow a better understanding of nonlinear phenomena that occur in structural dynamics.   This work is intended for graduate engineering students who want to expand their knowledge on the dynamic behavior of structures, specifically in the nonlinear field, by presenting the basis of dynamic balance in non‐linear behavior structures due to the material and kinematics mechanical effects.   Particularly, this publication shows the solution of the equation of dynamic equilibrium for structure with nonlinear time‐independent materials (plasticity, damage and frequencies evolution), as well as those time dependent non‐linear behavior materials (viscoelasticity and viscoplasticity). The convergence conditions for the non‐linear dynamic structure solution  are studied, and the theoretical concepts and its programming algorithms are presented.  

  14. Vehicle Dynamics and Control

    CERN Document Server

    Rajamani, Rajesh

    2012-01-01

    Vehicle Dynamics and Control provides a comprehensive coverage of vehicle control systems and the dynamic models used in the development of these control systems. The control system applications covered in the book include cruise control, adaptive cruise control, ABS, automated lane keeping, automated highway systems, yaw stability control, engine control, passive, active and semi-active suspensions, tire-road friction coefficient estimation, rollover prevention, and hybrid electric vehicle. In developing the dynamic model for each application, an effort is made to both keep the model simple enough for control system design but at the same time rich enough to capture the essential features of the dynamics. A special effort has been made to explain the several different tire models commonly used in literature and to interpret them physically. In the second edition of the book, chapters on roll dynamics, rollover prevention and hybrid electric vehicles have been added, and the chapter on electronic stability co...

  15. Dynamic Capabilities and Performance

    DEFF Research Database (Denmark)

    Wilden, Ralf; Gudergan, Siegfried P.; Nielsen, Bo Bernhard

    2013-01-01

    Dynamic capabilities are widely considered to incorporate those processes that enable organizations to sustain superior performance over time. In this paper, we argue theoretically and demonstrate empirically that these effects are contingent on organizational structure and the competitive...... intensity in the market. Results from partial least square structural equation modeling (PLS-SEM) analyses indicate that organic organizational structures facilitate the impact of dynamic capabilities on organizational performance. Furthermore, we find that the performance effects of dynamic capabilities...... are contingent on the competitive intensity faced by firms. Our findings demonstrate the performance effects of internal alignment between organizational structure and dynamic capabilities, as well as the external fit of dynamic capabilities with competitive intensity. We outline the advantages of PLS...

  16. Bursty human dynamics

    CERN Document Server

    Karsai, Márton; Kaski, Kimmo

    2018-01-01

    This book provides a comprehensive overview on emergent bursty patterns in the dynamics of human behaviour. It presents common and alternative understanding of the investigated phenomena, and points out open questions worthy of further investigations. The book is structured as follows. In the introduction the authors discuss the motivation of the field, describe bursty phenomena in case of human behaviour, and relate it to other disciplines. The second chapter addresses the measures commonly used to characterise heterogeneous signals, bursty human dynamics, temporal paths, and correlated behaviour. These definitions are first introduced to set the basis for the discussion of the third chapter about the observations of bursty human patterns in the dynamics of individuals, dyadic interactions, and collective behaviour. The subsequent fourth chapter discusses the models of bursty human dynamics. Various mechanisms have been proposed about the source of the heterogeneities in human dynamics, which leads to the in...

  17. Dynamics of Multibody Systems

    Science.gov (United States)

    Shabana, Ahmed A.

    2005-05-01

    Dynamics of Multibody Systems introduces multibody dynamics, with an emphasis on flexible body dynamics. Many common mechanisms such as automobiles, space structures, robots, and micro machines have mechanical and structural systems that consist of interconnected rigid and deformable components. The dynamics of these large-scale, multibody systems are highly nonlinear, presenting complex problems that in most cases can only be solved with computer-based techniques. The book begins with a review of the basic ideas of kinematics and the dynamics of rigid and deformable bodies before moving on to more advanced topics and computer implementation. This new edition includes important new developments relating to the problem of large deformations and numerical algorithms as applied to flexible multibody systems. The book's wealth of examples and practical applications will be useful to graduate students, researchers, and practicing engineers working on a wide variety of flexible multibody systems.

  18. Dynamics of aesthetic appreciation

    Science.gov (United States)

    Carbon, Claus-Christian

    2012-03-01

    Aesthetic appreciation is a complex cognitive processing with inherent aspects of cold as well as hot cognition. Research from the last decades of empirical has shown that evaluations of aesthetic appreciation are highly reliable. Most frequently, facial attractiveness was used as the corner case for investigating aesthetic appreciation. Evaluating facial attractiveness shows indeed high internal consistencies and impressively high inter-rater reliabilities, even across cultures. Although this indicates general and stable mechanisms underlying aesthetic appreciation, it is also obvious that our taste for specific objects changes dynamically. Aesthetic appreciation on artificial object categories, such as fashion, design or art is inherently very dynamic. Gaining insights into the cognitive mechanisms that trigger and enable corresponding changes of aesthetic appreciation is of particular interest for research as this will provide possibilities to modeling aesthetic appreciation for longer durations and from a dynamic perspective. The present paper refers to a recent two-step model ("the dynamical two-step-model of aesthetic appreciation"), dynamically adapting itself, which accounts for typical dynamics of aesthetic appreciation found in different research areas such as art history, philosophy and psychology. The first step assumes singular creative sources creating and establishing innovative material towards which, in a second step, people adapt by integrating it into their visual habits. This inherently leads to dynamic changes of the beholders' aesthetic appreciation.

  19. Basic structural dynamics

    CERN Document Server

    Anderson, James C

    2012-01-01

    A concise introduction to structural dynamics and earthquake engineering Basic Structural Dynamics serves as a fundamental introduction to the topic of structural dynamics. Covering single and multiple-degree-of-freedom systems while providing an introduction to earthquake engineering, the book keeps the coverage succinct and on topic at a level that is appropriate for undergraduate and graduate students. Through dozens of worked examples based on actual structures, it also introduces readers to MATLAB, a powerful software for solving both simple and complex structural d

  20. Elements of analytical dynamics

    CERN Document Server

    Kurth, Rudolph; Stark, M

    1976-01-01

    Elements of Analytical Dynamics deals with dynamics, which studies the relationship between motion of material bodies and the forces acting on them. This book is a compilation of lectures given by the author at the Georgia and Institute of Technology and formed a part of a course in Topological Dynamics. The book begins by discussing the notions of space and time and their basic properties. It then discusses the Hamilton-Jacobi theory and Hamilton's principle and first integrals. The text concludes with a discussion on Jacobi's geometric interpretation of conservative systems. This book will

  1. High enthalpy gas dynamics

    CERN Document Server

    Rathakrishnan, Ethirajan

    2014-01-01

    This is an introductory level textbook which explains the elements of high temperature and high-speed gas dynamics. written in a clear and easy to follow style, the author covers all the latest developments in the field including basic thermodynamic principles, compressible flow regimes and waves propagation in one volume covers theoretical modeling of High Enthalpy Flows, with particular focus on problems in internal and external gas-dynamic flows, of interest in the fields of rockets propulsion and hypersonic aerodynamics High enthalpy gas dynamics is a compulsory course for aerospace engine

  2. Fundamentals of gas dynamics

    CERN Document Server

    Babu, V

    2014-01-01

    Fundamentals of Gas Dynamics, Second Edition isa comprehensively updated new edition and now includes a chapter on the gas dynamics of steam. It covers the fundamental concepts and governing equations of different flows, and includes end of chapter exercises based on the practical applications. A number of useful tables on the thermodynamic properties of steam are also included.Fundamentals of Gas Dynamics, Second Edition begins with an introduction to compressible and incompressible flows before covering the fundamentals of one dimensional flows and normal shock wav

  3. Discrete Dynamics Lab

    Science.gov (United States)

    Wuensche, Andrew

    DDLab is interactive graphics software for creating, visualizing, and analyzing many aspects of Cellular Automata, Random Boolean Networks, and Discrete Dynamical Networks in general and studying their behavior, both from the time-series perspective — space-time patterns, and from the state-space perspective — attractor basins. DDLab is relevant to research, applications, and education in the fields of complexity, self-organization, emergent phenomena, chaos, collision-based computing, neural networks, content addressable memory, genetic regulatory networks, dynamical encryption, generative art and music, and the study of the abstract mathematical/physical/dynamical phenomena in their own right.

  4. Dynamic Characteristics and Models

    DEFF Research Database (Denmark)

    Pedersen, Lars

    2007-01-01

    is that the dynamic characteristics of a flooring-system do not only depend on material characteristics, floor dimensions and boundary conditions. They are also influenced by the presence of stationary persons on the floor, and these persons may or may not be present. Stationary persons are humans in, for example......, sitting or standing posture, and that these persons influence the dynamic characteristics of the floor (floor frequency and floor damping) is demonstrated in the paper. The mechanism of the dynamic interaction between the floor mass and the mass of stationary persons is generally not well understood...

  5. Fluid dynamics transactions

    CERN Document Server

    Fiszdon, W

    1965-01-01

    Fluid Dynamics Transactions, Volume 2 compiles 46 papers on fluid dynamics, a subdiscipline of fluid mechanics that deals with fluid flow. The topics discussed in this book include developments in interference theory for aeronautical applications; diffusion from sources in a turbulent boundary layer; unsteady motion of a finite wing span in a compressible medium; and wall pressure covariance and comparison with experiment. The certain classes of non-stationary axially symmetric flows in magneto-gas-dynamics; description of the phenomenon of secondary flows in curved channels by means of co

  6. Stability of dynamical systems

    CERN Document Server

    Liao, Xiaoxin; Yu, P 0

    2007-01-01

    The main purpose of developing stability theory is to examine dynamic responses of a system to disturbances as the time approaches infinity. It has been and still is the object of intense investigations due to its intrinsic interest and its relevance to all practical systems in engineering, finance, natural science and social science. This monograph provides some state-of-the-art expositions of major advances in fundamental stability theories and methods for dynamic systems of ODE and DDE types and in limit cycle, normal form and Hopf bifurcation control of nonlinear dynamic systems.ʺ Presents

  7. Process Fairness and Dynamic Consistency

    NARCIS (Netherlands)

    S.T. Trautmann (Stefan); P.P. Wakker (Peter)

    2010-01-01

    textabstractAbstract: When process fairness deviates from outcome fairness, dynamic inconsistencies can arise as in nonexpected utility. Resolute choice (Machina) can restore dynamic consistency under nonexpected utility without using Strotz's precommitment. It can similarly justify dynamically

  8. Assimilation Dynamic Network (ADN) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Assimilation Dynamic Network (ADN) is a dynamic inter-processor communication network that spans heterogeneous processor architectures, unifying components,...

  9. Discrete Wigner function dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Klimov, A B; Munoz, C [Departamento de Fisica, Universidad de Guadalajara, Revolucion 1500, 44410, Guadalajara, Jalisco (Mexico)

    2005-12-01

    We study the evolution of the discrete Wigner function for prime and the power of prime dimensions using the discrete version of the star-product operation. Exact and semiclassical dynamics in the limit of large dimensions are considered.

  10. Discrete dynamical models

    CERN Document Server

    Salinelli, Ernesto

    2014-01-01

    This book provides an introduction to the analysis of discrete dynamical systems. The content is presented by an unitary approach that blends the perspective of mathematical modeling together with the ones of several discipline as Mathematical Analysis, Linear Algebra, Numerical Analysis, Systems Theory and Probability. After a preliminary discussion of several models, the main tools for the study of linear and non-linear scalar dynamical systems are presented, paying particular attention to the stability analysis. Linear difference equations are studied in detail and an elementary introduction of Z and Discrete Fourier Transform is presented. A whole chapter is devoted to the study of bifurcations and chaotic dynamics. One-step vector-valued dynamical systems are the subject of three chapters, where the reader can find the applications to positive systems, Markov chains, networks and search engines. The book is addressed mainly to students in Mathematics, Engineering, Physics, Chemistry, Biology and Economic...

  11. Market Squid Population Dynamics

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains population dynamics data on paralarvae, juvenile and adult market squid collected off California and the US Pacific Northwest. These data were...

  12. Transonic Dynamics Tunnel (TDT)

    Data.gov (United States)

    Federal Laboratory Consortium — The Transonic Dynamics Tunnel (TDT) is a continuous flow wind-tunnel facility capable of speeds up to Mach 1.2 at stagnation pressures up to one atmosphere. The TDT...

  13. Invitation to dynamical systems

    CERN Document Server

    Scheinerman, Edward R

    2012-01-01

    This text is designed for those who wish to study mathematics beyond linear algebra but are unready for abstract material. Rather than a theorem-proof-corollary exposition, it stresses geometry, intuition, and dynamical systems. 1996 edition.

  14. Dynamic origin of species

    OpenAIRE

    Sadovsky, Michael G.

    2008-01-01

    A simple model of species origin resulted from dynamic features of a population, solely, is developed. The model is based on the evolution optimality in space distribution, and the selection is gone over the mobility. Some biological issues are discussed.

  15. Gun Dynamics Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Gun Dynamics Laboratory is a research multi-task facility, which includes two firing bays, a high bay area and a second floor laboratory space. The high bay area...

  16. Controlling Uncertain Dynamical Systems

    Indian Academy of Sciences (India)

    Author Affiliations. N Ananthkrishnan1 Rashi Bansal2. Head, CAE Analysis & Design Zeus Numerix Pvt Ltd. M-03, SINE, IIT Bombay Powai Mumbai 400076, India. MTech (Aerospace Engineering) with specialization in Dynamics & Control from IIT Bombay.

  17. Fish population dynamics

    National Research Council Canada - National Science Library

    Gulland, J. A

    1977-01-01

    This book describes how the dynamics of fish populations can be analysed in terms of the factors affecting their rates of growth, mortality and reproduction, with particular emphasis on the effects of fishing...

  18. Dynamic plasmonic colour display

    Science.gov (United States)

    Duan, Xiaoyang; Kamin, Simon; Liu, Na

    2017-01-01

    Plasmonic colour printing based on engineered metasurfaces has revolutionized colour display science due to its unprecedented subwavelength resolution and high-density optical data storage. However, advanced plasmonic displays with novel functionalities including dynamic multicolour printing, animations, and highly secure encryption have remained in their infancy. Here we demonstrate a dynamic plasmonic colour display technique that enables all the aforementioned functionalities using catalytic magnesium metasurfaces. Controlled hydrogenation and dehydrogenation of the constituent magnesium nanoparticles, which serve as dynamic pixels, allow for plasmonic colour printing, tuning, erasing and restoration of colour. Different dynamic pixels feature distinct colour transformation kinetics, enabling plasmonic animations. Through smart material processing, information encoded on selected pixels, which are indiscernible to both optical and scanning electron microscopies, can only be read out using hydrogen as a decoding key, suggesting a new generation of information encryption and anti-counterfeiting applications. PMID:28232722

  19. Stochastic dynamics and irreversibility

    CERN Document Server

    Tomé, Tânia

    2015-01-01

    This textbook presents an exposition of stochastic dynamics and irreversibility. It comprises the principles of probability theory and the stochastic dynamics in continuous spaces, described by Langevin and Fokker-Planck equations, and in discrete spaces, described by Markov chains and master equations. Special concern is given to the study of irreversibility, both in systems that evolve to equilibrium and in nonequilibrium stationary states. Attention is also given to the study of models displaying phase transitions and critical phenomema both in thermodynamic equilibrium and out of equilibrium. These models include the linear Glauber model, the Glauber-Ising model, lattice models with absorbing states such as the contact process and those used in population dynamic and spreading of epidemic, probabilistic cellular automata, reaction-diffusion processes, random sequential adsorption and dynamic percolation. A stochastic approach to chemical reaction is also presented.The textbook is intended for students of ...

  20. Longitudinal beam dynamics

    CERN Document Server

    Tecker, F.

    2014-01-01

    The course gives a summary of longitudinal beam dynamics for both linear and circular accelerators. After discussing different types of acceleration methods and synchronism conditions, it focuses on the particle motion in synchrotrons.

  1. Structure, Reactivity and Dynamics

    Indian Academy of Sciences (India)

    Oppenheimer approx- imation are also studied. New and improved methodologies have been applied to study multi-surface multi-mode nuclear dynamics. The interesting phenomenon involving the geometric phase which may have important ...

  2. Rovibrational Quantum Dynamics of the Methane-Water Dimer

    Science.gov (United States)

    Sarka, János; Császár, Attila; Mátyus, Edit

    2017-06-01

    The challenging quantum dynamical description of the CH_4.H_2O complex has been solved variationally to provide theoretical explanation and assignment to the high-resolution spectroscopic measurements of the methane-water dimer carried out some twenty years ago. The computational results are in excellent agreement with the reported experimental transitions and the experimentally observed reversed rovibrational sequences, i.e., formally negative rotational excitation energies, are also obtained in the computations. In order to better understand the origin of these peculiar features in the energy-level spectrum, we studied all four possible combinations of the light and heavy isotopologues of methane and water and analyzed their rovibrational states using two limiting model systems: the rigidly rotating (RR) molecule and the coupled rotor (CR) system corresponding to the coupling of the two rotating monomers. All rovibrational quantum dynamical computations^{a,c} were carried out with rigid monomers and J = 0,1,2 total angular momentum quantum numbers using the fourth-age quantum chemical code GENIUSH and two different methane-water potential energy surfaces (PES). The numerical and formal analysis of the wave functions give insight into a fascinating complex world worth for further theoretical and experimental inquiries. J. Sarka, A. G. Császár, S. C. Althorpe, D. J. Wales and E. Mátyus, Phys. Chem. Chem. Phys. 18, 22816 (2016). L. Dore, R. C. Cohen, C. A. Schmuttenmaer, K. L. Busarow, M. J. Elrod, J. G. Loeser and R. J. Saykally, J. Chem. Phys. 100, 863 (1994). J. Sarka, A. G. Császár and E. Mátyus, Phys. Chem. Chem. Phys. accepted for publication (2017).} E. Mátyus, G. Czakó and A. G. Császár, J. Chem. Phys. 130, 134112 (2009). C. Fábri, E. Mátyus and A. G. Császár, J. Chem. Phys. 134, 074105 (2011). O. Akin-Ojo and K. Szalewicz, J. Chem. Phys. 123, 134311 (2005). C. Qu, R. Conte, P. L. Houston and J. M. Bowman, Phys. Chem. Chem. Phys. 17, 8172 (2015).

  3. Dynamics of curved fronts

    CERN Document Server

    Pelce, Pierre

    1989-01-01

    In recent years, much progress has been made in the understanding of interface dynamics of various systems: hydrodynamics, crystal growth, chemical reactions, and combustion. Dynamics of Curved Fronts is an important contribution to this field and will be an indispensable reference work for researchers and graduate students in physics, applied mathematics, and chemical engineering. The book consist of a 100 page introduction by the editor and 33 seminal articles from various disciplines.

  4. Managing Dynamic Competition

    OpenAIRE

    Tracy R. Lewis; Huseyin Yildirim

    2002-01-01

    In many important high-technology markets, including software development, data processing, communications, aeronautics, and defense, suppliers learn through experience how to provide better service at lower cost. This paper examines how a buyer designs dynamic competition among rival suppliers to exploit learning economies while minimizing the costs of becoming locked in to one producer. Strategies for controlling dynamic competition include the handicapping of more efficient suppliers in pr...

  5. Dynamics of Soft Matter

    CERN Document Server

    García Sakai, Victoria; Chen, Sow-Hsin

    2012-01-01

    Dynamics of Soft Matter: Neutron Applications provides an overview of neutron scattering techniques that measure temporal and spatial correlations simultaneously, at the microscopic and/or mesoscopic scale. These techniques offer answers to new questions arising at the interface of physics, chemistry, and biology. Knowledge of the dynamics at these levels is crucial to understanding the soft matter field, which includes colloids, polymers, membranes, biological macromolecules, foams, emulsions towards biological & biomimetic systems, and phenomena involving wetting, friction, adhesion, or micr

  6. Static vs Dynamic SAGAs

    Directory of Open Access Journals (Sweden)

    Ivan Lanese

    2010-10-01

    Full Text Available SAGAs calculi (or simply SAGAs have been proposed by Bruni et al. as a model for long-running transactions. The approach therein can be considered static, while a dynamic approach has been proposed by Lanese and Zavattaro. In this paper we first extend both static SAGAs (in the centralized interruption policy and dynamic SAGAs to deal with nesting, then we compare the two approaches.

  7. Photochemical reaction dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Moore, B.C. [Lawrence Berkeley Laboratory, Livermore, CA (United States)

    1993-12-01

    The purpose of the program is to develop a fundamental understanding of unimolecular and bimolecular reaction dynamics with application in combustion and energy systems. The energy dependence in ketene isomerization, ketene dissociation dynamics, and carbonyl substitution on organometallic rhodium complexes in liquid xenon have been studied. Future studies concerning unimolecular processes in ketene as well as energy transfer and kinetic studies of methylene radicals are discussed.

  8. DPS - Dynamic Parallel Schedules

    OpenAIRE

    IEEE Press; Gerlach, S.; Hersch, R. D.

    2003-01-01

    Dynamic Parallel Schedules (DPS) is a high-level framework for developing parallel applications on distributed memory computers (e.g. clusters of PC). Its model relies on compositional customizable split-compute-merge graphs of operations (directed acyclic flow graphs). The graphs and the mapping of operations to processing nodes are specified dynamically at runtime. DPS applications are pipelined and multithreaded by construction, ensuring a maximal overlap of computations and communications...

  9. Dynamically typed languages

    OpenAIRE

    Tratt, Laurence

    2009-01-01

    Dynamically typed languages such as Python and Ruby have experienced a rapid grown in popularity in recent times. However, there is much confusion as to what makes these languages interesting relative to statically typed languages, and little knowledge of their rich history. In this chapter I explore the general topic of dynamically typed languages, how they differ from statically typed languages, their history, and their defining features.

  10. Homogenization of dislocation dynamics

    Energy Technology Data Exchange (ETDEWEB)

    El Hajj, Ahmad; Ibrahim, Hassan; Monneau, Regis, E-mail: elhajj@cermics.enpc.fr, E-mail: ibrahim@cermics.enpc.fr, E-mail: monneau@cermics.enpc.fr [CERMICS, ENPC, 6 and 8 avenue Blaise Pascal, Cite Descartes, Champs sur Marne, 77455 Marne-la-Valle Cedex 2 (France)

    2009-07-15

    In this paper we consider the dynamics of dislocations with the same Burgers vector, contained in the same glide plane, and moving in a material with periodic obstacles. We study two cases: i) the particular case of parallel straight dislocations and ii) the general case of curved dislocations. In each case, we perform rigorously the homogenization of the dynamics and predict the corresponding effective macroscopic elasto-visco-plastic flow rule.

  11. Assimilating seizure dynamics.

    Directory of Open Access Journals (Sweden)

    Ghanim Ullah

    2010-05-01

    Full Text Available Observability of a dynamical system requires an understanding of its state-the collective values of its variables. However, existing techniques are too limited to measure all but a small fraction of the physical variables and parameters of neuronal networks. We constructed models of the biophysical properties of neuronal membrane, synaptic, and microenvironment dynamics, and incorporated them into a model-based predictor-controller framework from modern control theory. We demonstrate that it is now possible to meaningfully estimate the dynamics of small neuronal networks using as few as a single measured variable. Specifically, we assimilate noisy membrane potential measurements from individual hippocampal neurons to reconstruct the dynamics of networks of these cells, their extracellular microenvironment, and the activities of different neuronal types during seizures. We use reconstruction to account for unmeasured parts of the neuronal system, relating micro-domain metabolic processes to cellular excitability, and validate the reconstruction of cellular dynamical interactions against actual measurements. Data assimilation, the fusing of measurement with computational models, has significant potential to improve the way we observe and understand brain dynamics.

  12. Static and dynamic properties of dissipative particle dynamics

    NARCIS (Netherlands)

    Marsh, C.A.; Backx, G.|info:eu-repo/dai/nl/304846724; Ernst, M.H.|info:eu-repo/dai/nl/114179247

    The algorithm for the dissipative particle dynamics (DPD) fluid, the dynamics of which is conceptually a combination of molecular dynamics, Brownian dynamics, and lattice gas automata, is designed for simulating rheological properties of complex fluids on hydrodynamic time scales. This paper

  13. Modeling dynamic swarms

    KAUST Repository

    Ghanem, Bernard

    2013-01-01

    This paper proposes the problem of modeling video sequences of dynamic swarms (DSs). We define a DS as a large layout of stochastically repetitive spatial configurations of dynamic objects (swarm elements) whose motions exhibit local spatiotemporal interdependency and stationarity, i.e., the motions are similar in any small spatiotemporal neighborhood. Examples of DS abound in nature, e.g., herds of animals and flocks of birds. To capture the local spatiotemporal properties of the DS, we present a probabilistic model that learns both the spatial layout of swarm elements (based on low-level image segmentation) and their joint dynamics that are modeled as linear transformations. To this end, a spatiotemporal neighborhood is associated with each swarm element, in which local stationarity is enforced both spatially and temporally. We assume that the prior on the swarm dynamics is distributed according to an MRF in both space and time. Embedding this model in a MAP framework, we iterate between learning the spatial layout of the swarm and its dynamics. We learn the swarm transformations using ICM, which iterates between estimating these transformations and updating their distribution in the spatiotemporal neighborhoods. We demonstrate the validity of our method by conducting experiments on real and synthetic video sequences. Real sequences of birds, geese, robot swarms, and pedestrians evaluate the applicability of our model to real world data. © 2012 Elsevier Inc. All rights reserved.

  14. Dynamics in Epistasis Analysis.

    Science.gov (United States)

    Awdeh, Aseel; Phenix, Hilary; Kaern, Mads; Perkins, Theodore

    2017-01-16

    Finding regulatory relationships between genes, including the direction and nature of influence between them, is a fundamental challenge in the field of molecular genetics. One classical approach to this problem is epistasis analysis. Broadly speaking, epistasis analysis infers the regulatory relationships between a pair of genes in a genetic pathway by considering the patterns of change in an observable trait resulting from single and double deletion of genes. While classical epistasis analysis has yielded deep insights on numerous genetic pathways, it is not without limitations. Here, we explore the possibility of dynamic epistasis analysis, in which, in addition to performing genetic perturbations of a pathway, we drive the pathway by a time-varying upstream signal. We explore the theoretical power of dynamical epistasis analysis by conducting an identifiability analysis of Boolean models of genetic pathways, comparing static and dynamic approaches. We find that even relatively simple input dynamics greatly increases the power of epistasis analysis to discriminate alternative network structures. Further, we explore the question of experiment design, and show that a subset of short time-varying signals, which we call dynamic primitives, allow maximum discriminative power with a reduced number of experiments.

  15. Dynamic Whitening Saliency.

    Science.gov (United States)

    Leboran, Victor; Garcia-Diaz, Anton; Fdez-Vidal, Xose R; Pardo, Xose M

    2017-05-01

    General dynamic scenes involve multiple rigid and flexible objects, with relative and common motion, camera induced or not. The complexity of the motion events together with their strong spatio-temporal correlations make the estimation of dynamic visual saliency a big computational challenge. In this work, we propose a computational model of saliency based on the assumption that perceptual relevant information is carried by high-order statistical structures. Through whitening, we completely remove the second-order information (correlations and variances) of the data, gaining access to the relevant information. The proposed approach is an analytically tractable and computationally simple framework which we call Dynamic Adaptive Whitening Saliency (AWS-D). For model assessment, the provided saliency maps were used to predict the fixations of human observers over six public video datasets, and also to reproduce the human behavior under certain psychophysical experiments (dynamic pop-out). The results demonstrate that AWS-D beats state-of-the-art dynamic saliency models, and suggest that the model might contain the basis to understand the key mechanisms of visual saliency. Experimental evaluation was performed using an extension to video of the well-known methodology for static images, together with a bootstrap permutation test (random label hypothesis) which yields additional information about temporal evolution of the metrics statistical significance.

  16. Astrophysical fluid dynamics

    Science.gov (United States)

    Ogilvie, Gordon I.

    2016-06-01

    > These lecture notes and example problems are based on a course given at the University of Cambridge in Part III of the Mathematical Tripos. Fluid dynamics is involved in a very wide range of astrophysical phenomena, such as the formation and internal dynamics of stars and giant planets, the workings of jets and accretion discs around stars and black holes and the dynamics of the expanding Universe. Effects that can be important in astrophysical fluids include compressibility, self-gravitation and the dynamical influence of the magnetic field that is `frozen in' to a highly conducting plasma. The basic models introduced and applied in this course are Newtonian gas dynamics and magnetohydrodynamics (MHD) for an ideal compressible fluid. The mathematical structure of the governing equations and the associated conservation laws are explored in some detail because of their importance for both analytical and numerical methods of solution, as well as for physical interpretation. Linear and nonlinear waves, including shocks and other discontinuities, are discussed. The spherical blast wave resulting from a supernova, and involving a strong shock, is a classic problem that can be solved analytically. Steady solutions with spherical or axial symmetry reveal the physics of winds and jets from stars and discs. The linearized equations determine the oscillation modes of astrophysical bodies, as well as their stability and their response to tidal forcing.

  17. System dynamics with interaction discontinuity

    CERN Document Server

    Luo, Albert C J

    2015-01-01

    This book describes system dynamics with discontinuity caused by system interactions and presents the theory of flow singularity and switchability at the boundary in discontinuous dynamical systems. Based on such a theory, the authors address dynamics and motion mechanism of engineering discontinuous systems due to interaction. Stability and bifurcations of fixed points in nonlinear discrete dynamical systems are presented, and mapping dynamics are developed for analytical predictions of periodic motions in engineering discontinuous dynamical systems. Ultimately, the book provides an alternative way to discuss the periodic and chaotic behaviors in discontinuous dynamical systems.

  18. Vehicle dynamics theory and application

    CERN Document Server

    Jazar, Reza N

    2017-01-01

    This intermediate textbook is appropriate for students in vehicle dynamics courses, in their last year of undergraduate study or their first year of graduate study. It is also appropriate for mechanical engineers, automotive engineers, and researchers in the area of vehicle dynamics for continuing education or as a reference. It addresses fundamental and advanced topics, and a basic knowledge of kinematics and dynamics, as well as numerical methods, is expected. The contents are kept at a theoretical-practical level, with a strong emphasis on application. This third edition has been reduced by 25%, to allow for coverage over one semester, as opposed to the previous edition that needed two semesters for coverage. The textbook is composed of four parts: Vehicle Motion: covers tire dynamics, forward vehicle dynamics, and driveline dynamics Vehicle Kinematics: covers applied kinematics, applied mechanisms, steering dynamics, and suspension mechanisms Vehicle Dynamics: covers applied dynamics, vehicle planar dynam...

  19. Dynamic behaviour of a ferro-electric liquid crystal by means of nuclear magnetic resonance and dielectric spectroscopy

    Science.gov (United States)

    Domenici, Valentina; Marini, Alberto; Menicagli, Rita; Veracini, Carlo Alberto; Bubnov, Aleksej M.; Glogarova, Milada

    2007-05-01

    The field of ferroelectric liquid crystals (FLCs) is one of the most fascinating aspects of the Science of Materials for their interesting electro-optic applications. Among different chemical and physical properties those related to the molecular dynamics are very stimulating due to the relationship between molecular motions and macroscopic response to external fields, such as electric and magnetic ones. In this work, the molecular dynamics of a ferroelectric smectogen, namely the (S)-2-methylbutyl-[4'-(4"-heptyloxyphenyl)-benzoyl-4-oxy-(S)-2-((S)-2')-benzoyl)-propionyl)]-propionate (ZLL 7/*) has been investigated by means of 2H NMR and dielectric relaxation techniques. The first method allows us to get information on the molecular motions in the fast motion regime, in particular the diffusion reorientational motions of the whole molecule, as well as of the internal motions affecting the phenyl and biphenyl fragments. The second technique, which covers the slow motion regime, has been used to detect collective motions and fluctuation modes. This study allows us to have a complete idea of molecular motions in the different smectic phases formed by the ZLL 7/* mesogens, in particular the paraelectric smectic A (SmA), the ferroelectric smectic C* (SmC*), the antiferroelectric smectic C* A (SmC* A) and the re-entrant ferroelectric smectic C* (SmC* r) phases. This last phase has been investigated for the first time in this work, from the point of view of the dynamic behaviour. All results will be discussed in the framework of the molecular dynamics of ferroelectric liquid crystals, reported in the literature so far.

  20. Dynamics in geometrical confinement

    CERN Document Server

    Kremer, Friedrich

    2014-01-01

    This book describes the dynamics of low molecular weight and polymeric molecules when they are constrained under conditions of geometrical confinement. It covers geometrical confinement in different dimensionalities: (i) in nanometer thin layers or self supporting films (1-dimensional confinement) (ii) in pores or tubes with nanometric diameters (2-dimensional confinement) (iii) as micelles embedded in matrices (3-dimensional) or as nanodroplets.The dynamics under such conditions have been a much discussed and central topic in the focus of intense worldwide research activities within the last two decades. The present book discusses how the resulting molecular mobility is influenced by the subtle counterbalance between surface effects (typically slowing down molecular dynamics through attractive guest/host interactions) and confinement effects (typically increasing the mobility). It also explains how these influences can be modified and tuned, e.g. through appropriate surface coatings, film thicknesses or pore...

  1. Lagrangian and Hamiltonian dynamics

    CERN Document Server

    Mann, Peter

    2018-01-01

    An introductory textbook exploring the subject of Lagrangian and Hamiltonian dynamics, with a relaxed and self-contained setting. Lagrangian and Hamiltonian dynamics is the continuation of Newton's classical physics into new formalisms, each highlighting novel aspects of mechanics that gradually build in complexity to form the basis for almost all of theoretical physics. Lagrangian and Hamiltonian dynamics also acts as a gateway to more abstract concepts routed in differential geometry and field theories and can be used to introduce these subject areas to newcomers. Journeying in a self-contained manner from the very basics, through the fundamentals and onwards to the cutting edge of the subject, along the way the reader is supported by all the necessary background mathematics, fully worked examples, thoughtful and vibrant illustrations as well as an informal narrative and numerous fresh, modern and inter-disciplinary applications. The book contains some unusual topics for a classical mechanics textbook. Mo...

  2. Vorticity and vortex dynamics

    CERN Document Server

    Wu, Jie-Zhi; Zhou, M-D

    2006-01-01

    The importance of vorticity and vortex dynamics has now been well rec- nized at both fundamental and applied levels of ?uid dynamics, as already anticipatedbyTruesdellhalfcenturyagowhenhewrotethe?rstmonograph onthesubject, The Kinematics of Vorticity(1954);andasalsoevidencedby the appearance of several books on this ?eld in 1990s. The present book is characterizedbythefollowingfeatures: 1. A basic physical guide throughout the book. The material is directed by a basic observation on the splitting and coupling of two fundamental processes in ?uid motion, i.e., shearing (unique to ?uid) and compre- ing/expanding.Thevorticityplaysakeyroleintheformer,andavortex isnothingbuta?uidbodywithhighconcentrationofvorticitycompared to its surrounding ?uid. Thus, the vorticity and vortex dynamics is - cordinglyde?nedasthetheoryofshearingprocessanditscouplingwith compressing/expandingprocess. 2. A description of the vortex evolution following its entire life.Thisbegins from the generation of vorticity to the formation of thi...

  3. Dynamics of Earthquake Faults

    CERN Document Server

    Carlson, J M; Shaw, B E

    1993-01-01

    We present an overview of our ongoing studies of the rich dynamical behavior of the uniform, deterministic Burridge--Knopoff model of an earthquake fault. We discuss the behavior of the model in the context of current questions in seismology. Some of the topics considered include: (1) basic properties of the model, such as the magnitude vs. frequency distribution and the distinction between small and large events; (2) dynamics of individual events, including dynamical selection of rupture propagation speeds; (3) generalizations of the model to more realistic, higher dimensional models; (4) studies of predictability, in which artificial catalogs generated by the model are used to test and determine the limitations of pattern recognition algorithms used in seismology.

  4. Fractional Dynamics and Control

    CERN Document Server

    Machado, José; Luo, Albert

    2012-01-01

    Fractional Dynamics and Control provides a comprehensive overview of recent advances in the areas of nonlinear dynamics, vibration and control with analytical, numerical, and experimental results. This book provides an overview of recent discoveries in fractional control, delves into fractional variational principles and differential equations, and applies advanced techniques in fractional calculus to solving complicated mathematical and physical problems.Finally, this book also discusses the role that fractional order modeling can play in complex systems for engineering and science. Discusses how fractional dynamics and control can be used to solve nonlinear science and complexity issues Shows how fractional differential equations and models can be used to solve turbulence and wave equations in mechanics and gravity theories and Schrodinger’s equation  Presents factional relaxation modeling of dielectric materials and wave equations for dielectrics  Develops new methods for control and synchronization of...

  5. Dynamics of absence seizures

    Science.gov (United States)

    Deeba, Farah; Sanz-Leon, Paula; Robinson, Peter

    A neural field model of the corticothalamic system is used to investigate the dynamics of absence seizures in the presence of temporally varying connection strength between the cerebral cortex and thalamus. Variation of connection strength from cortex to thalamus drives the system into seizure once a threshold is passed and a supercritical Hopf bifurcation occurs. The dynamics and spectral characteristics of the resulting seizures are explored as functions of maximum connection strength, time above threshold, and ramp rate. The results enable spectral and temporal characteristics of seizures to be related to underlying physiological variations via nonlinear dynamics and neural field theory. Notably, this analysis adds to neural field modeling of a wide variety of brain activity phenomena and measurements in recent years. Australian Research Council Grants FL1401000225 and CE140100007.

  6. Introduction to dynamics

    CERN Document Server

    Pfeiffer, Friedrich

    2015-01-01

    This concise textbook for students preferably of a postgraduate level, but also for engineers in practice, contains the basic kinematical and kinetic structures of dynamics together with carefully selected applications. The book is a condensed introduction to the fundamental laws of kinematics and kinetics, on the most important principles of mechanics and presents the equations of motion in the form of Lagrange and Newton-Euler. Selected problems of linear and nonlinear dynamics are treated, as well as problems of vibration formation. The presented selection of topics gives a useful basis for stepping into more advanced problems of dynamics. The contents of this book represent the result of a regularly revised course, which has been and still is given for masters students at the Technische Universität München. .

  7. Dynamic Sensor Networks

    Directory of Open Access Journals (Sweden)

    Simone Gabriele

    2007-07-01

    Full Text Available The present paper discusses the possibility of using dynamic sensor networks for measurements over large areas. The main idea is to replace static networks, where the allocation of the sensors is pre defined, no matter how, and then the configuration is assumed and maintained, with a dynamic network whose configuration continuously changes in order to cover the whole measure area getting the different measures of the same point within a prefixed time interval. The main advantages are the reduced number of sensors required, a faster recover from damages, the possibility of changing dynamically the area or the subareas of interest, etc. The feasibility of such solution is shown by finding, in an optimal control problem formulation context, the trajectories of each sensor and the controls for such a motion. Simulation results are reported to highlight such results.

  8. Dynamically stabilized magnetic skyrmions

    Science.gov (United States)

    Zhou, Y.; Iacocca, E.; Awad, A. A.; Dumas, R. K.; Zhang, F. C.; Braun, H. B.; Åkerman, J.

    2015-09-01

    Magnetic skyrmions are topologically non-trivial spin textures that manifest themselves as quasiparticles in ferromagnetic thin films or noncentrosymmetric bulk materials. So far attention has focused on skyrmions stabilized either by the Dzyaloshinskii-Moriya interaction (DMI) or by dipolar interaction, where in the latter case the excitations are known as bubble skyrmions. Here we demonstrate the existence of a dynamically stabilized skyrmion, which exists even when dipolar interactions and DMI are absent. We establish how such dynamic skyrmions can be nucleated, sustained and manipulated in an effectively lossless medium under a nanocontact. As quasiparticles, they can be transported between two nanocontacts in a nanowire, even in complete absence of DMI. Conversely, in the presence of DMI, we observe that the dynamical skyrmion experiences strong breathing. All of this points towards a wide range of skyrmion manipulation, which can be studied in a much wider class of materials than considered so far.

  9. Conference on Multibody Dynamics

    CERN Document Server

    Multibody Dynamics : Computational Methods and Applications

    2014-01-01

    By having its origin in analytical and continuum mechanics, as well as in computer science and applied mathematics, multibody dynamics provides a basis for analysis and virtual prototyping of innovative applications in many fields of contemporary engineering. With the utilization of computational models and algorithms that classically belonged to different fields of applied science, multibody dynamics delivers reliable simulation platforms for diverse highly-developed industrial products such as vehicle and railway systems, aeronautical and space vehicles, robotic manipulators, smart structures, biomechanical applications and nano-technologies. The chapters of this volume are based on the revised and extended versions of the selected scientific papers from amongst 255 original contributions that have been accepted to be presented within the program of the distinguished international ECCOMAS conference. It reflects state-of-the-art in the advances of multibody dynamics, providing excellent insight in the recen...

  10. Dynamic Data Structures

    DEFF Research Database (Denmark)

    Kejlberg-Rasmussen, Casper

    In this thesis I will address three dynamic data structure problems using the concept of invariants. The first problem is maintaining a dynamically changing set of keys – a dictionary – where the queries we can ask are: does it contain a given key? and what is the preceding (or succeeding) key...... concept we use, throughout this thesis, to solve data structure problems is invariants. In the design of dynamic data structures we have some set of query and update operations which we want our data structure to support, but we do not choose the order that they are performed in. Invariants are logical...... structure is implicit, meaning that we do not use any extra space than that of the input keys. Our data structure is implicitly encoded through the permutation of the input keys. Other dictionaries with the working set property have constant factor overhead in the space usage, our dictionary has no overhead...

  11. Dynamics of aerospace vehicles

    Science.gov (United States)

    Schmidt, David K.

    1991-01-01

    The focus of this research was to address the modeling, including model reduction, of flexible aerospace vehicles, with special emphasis on models used in dynamic analysis and/or guidance and control system design. In the modeling, it is critical that the key aspects of the system being modeled be captured in the model. In this work, therefore, aspects of the vehicle dynamics critical to control design were important. In this regard, fundamental contributions were made in the areas of stability robustness analysis techniques, model reduction techniques, and literal approximations for key dynamic characteristics of flexible vehicles. All these areas are related. In the development of a model, approximations are always involved, so control systems designed using these models must be robust against uncertainties in these models.

  12. Dynamic lighting design

    DEFF Research Database (Denmark)

    Linnebjerg, Sofie

    Introduction to the concept of dynamic lighting design The importance of dynamic light to support health and well-being has been more and more recognized [Hansen et al., 2017]. Humans has through many years of evolution adapted to the changing light of the sun, varying through the day, seasons...... and under various weather conditions, creating a multitude of light settings. Humans live in interaction with this dynamic light and consider it as a natural part of our world [Mathiasen, 2015]. Furthermore, it has by the recent discovery of intrinsically photosensitive retinal ganglion cells in 2002...... [Berson et al., 2002] become apparent, that light, beside serving a purpose of enabling visual orientation, also are influencing the internal body clock, affecting sleep-wake cycle, immune responses, appetite, behaviour, mood, alertness and attention - depending on the duration, timing and quality...

  13. Dynamics of structures

    CERN Document Server

    Paultre, Patrick

    2013-01-01

    This book covers structural dynamics from a theoretical and algorithmic approach. It covers systems with both single and multiple degrees-of-freedom. Numerous case studies are given to provide the reader with a deeper insight into the practicalities of the area, and the solutions to these case studies are given in terms of real-time and frequency in both geometric and modal spaces. Emphasis is also given to the subject of seismic loading. The text is based on many lectures on the subject of structural dynamics given at numerous institutions and thus will be an accessible and practical aid to

  14. Introduction to cluster dynamics

    CERN Document Server

    Reinhard, Paul-Gerhard

    2008-01-01

    Clusters as mesoscopic particles represent an intermediate state of matter between single atoms and solid material. The tendency to miniaturise technical objects requires knowledge about systems which contain a ""small"" number of atoms or molecules only. This is all the more true for dynamical aspects, particularly in relation to the qick development of laser technology and femtosecond spectroscopy. Here, for the first time is a highly qualitative introduction to cluster physics. With its emphasis on cluster dynamics, this will be vital to everyone involved in this interdisciplinary subje

  15. Dynamic gamma knife radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Luan Shuang; Swanson, Nathan; Chen Zhe [Department of Computer Science, University of New Mexico, Albuquerque, NM 87131 (United States); Ma Lijun [Department of Radiation Oncology, University of California San Francisco, San Francisco, CA 94143 (United States)], E-mail: sluan@cs.unm.edu, E-mail: nate@cs.unm.edu, E-mail: zchen@cs.unm.edu, E-mail: lijunma@radonc.ucsf.edu

    2009-03-21

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

  16. Substructured multibody molecular dynamics.

    Energy Technology Data Exchange (ETDEWEB)

    Grest, Gary Stephen; Stevens, Mark Jackson; Plimpton, Steven James; Woolf, Thomas B. (Johns Hopkins University, Baltimore, MD); Lehoucq, Richard B.; Crozier, Paul Stewart; Ismail, Ahmed E.; Mukherjee, Rudranarayan M. (Rensselaer Polytechnic Institute, Troy, NY); Draganescu, Andrei I.

    2006-11-01

    We have enhanced our parallel molecular dynamics (MD) simulation software LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator, lammps.sandia.gov) to include many new features for accelerated simulation including articulated rigid body dynamics via coupling to the Rensselaer Polytechnic Institute code POEMS (Parallelizable Open-source Efficient Multibody Software). We use new features of the LAMMPS software package to investigate rhodopsin photoisomerization, and water model surface tension and capillary waves at the vapor-liquid interface. Finally, we motivate the recipes of MD for practitioners and researchers in numerical analysis and computational mechanics.

  17. Flight Dynamics Analysis Branch

    Science.gov (United States)

    Stengle, Tom; Flores-Amaya, Felipe

    2000-01-01

    This report summarizes the major activities and accomplishments carried out by the Flight Dynamics Analysis Branch (FDAB), Code 572, in support of flight projects and technology development initiatives in fiscal year 2000. The report is intended to serve as a summary of the type of support carried out by the FDAB, as well as a concise reference of key accomplishments and mission experience derived from the various mission support roles. The primary focus of the FDAB is to provide expertise in the disciplines of flight dynamics, spacecraft trajectory, attitude analysis, and attitude determination and control. The FDAB currently provides support for missions and technology development projects involving NASA, government, university, and private industry.

  18. Dynamics on Lorentz manifolds

    CERN Document Server

    Adams, Scot

    2001-01-01

    Within the general framework of the dynamics of "large" groups on geometric spaces, the focus is on the types of groups that can act in complicated ways on Lorentz manifolds, and on the structure of the resulting manifolds and actions. This particular area of dynamics is an active one, and not all the results are in their final form. However, at this point, a great deal can be said about the particular Lie groups that come up in this context. It is impressive that, even assuming very weak recurrence of the action, the list of possible groups is quite restricted. For the most complicated of the

  19. Designing Dynamic Atmospheres

    DEFF Research Database (Denmark)

    Kinch, Sofie; Højlund, Marie

    2012-01-01

    This paper addresses the notion of atmospheres from a designerly perspective, and discusses temporal challenges facing interaction designers when acknowledging the dynamic character of it. As atmospheres are created in the relation between body, space, and time, a pragmatic approach seems useful,....... The potentials and implica-­‐ tions are presented through a design case, Kidkit, highlighting temporality as design parametre within interaction design.......This paper addresses the notion of atmospheres from a designerly perspective, and discusses temporal challenges facing interaction designers when acknowledging the dynamic character of it. As atmospheres are created in the relation between body, space, and time, a pragmatic approach seems useful...

  20. Maya Studio Projects Dynamics

    CERN Document Server

    Palamar, Todd

    2009-01-01

    The only hands-on book devoted to mastering Maya's dynamics tools for water, wind, and fire. In the world of animation, the ability to create realistic water, wind, and fire effects is key. Autodesk Maya software includes powerful dynamics tools that have been used to design breathtaking effects for movies, games, commercials, and short films. This professional guide teaches you the primary techniques you need to make the most of Maya's toolkit, so you'll soon be creating water that ripples, gusting winds and gentle breezes, and flickering fires the way Hollywood pros do. The one-of-a-kind boo

  1. Cavitation bubble dynamics.

    Science.gov (United States)

    Lauterborn, W; Ohl, C D

    1997-04-01

    The dynamics of cavitation bubbles on water is investigated for bubbles produced optically and acoustically. Single bubble dynamics is studied with laser produced bubbles and high speed photography with framing rates up to 20.8 million frames per second. Examples for jet formation and shock wave emission are given. Acoustic cavitation is produced in water in the interior of piezoelectric cylinders of different sizes (up to 12 cm inner diameter). The filementary structure composed of bubbles is investigated and their light emission (sonoluminescence) studied for various driving strengths.

  2. Principles of dynamics

    CERN Document Server

    Hill, Rodney

    2013-01-01

    Principles of Dynamics presents classical dynamics primarily as an exemplar of scientific theory and method. This book is divided into three major parts concerned with gravitational theory of planetary systems; general principles of the foundations of mechanics; and general motion of a rigid body. Some of the specific topics covered are Keplerian Laws of Planetary Motion; gravitational potential and potential energy; and fields of axisymmetric bodies. The principles of work and energy, fictitious body-forces, and inertial mass are also looked into. Other specific topics examined are kinematics

  3. Organisations’ evolutionary dynamics: a group dynamics approach

    Directory of Open Access Journals (Sweden)

    Germán Eduardo Vargas

    2010-04-01

    Full Text Available Colombian entrepreneurs’ straggling, reactionary and inertial orientation has been inconsistently lustified by the availability of internal and leveraged resources, a concept intensifying deficient technological capacity. Company activity (seen as being a socioeconomic unit has been integrally orientated within an evolutionary framework by company identity and cohesion as well as adaptation and evolutionary mechanisms. The present document uses a group dynamics’ model to illustrate how knowledge-based strategic orientation and integration for innovation have become an imperative for development, from slight leverage, distinguishing between two evolutionary company forms: traditional economic (inertial, as they introduce sporadic incremental improvements and modern companies (dynamic and radical innovators. Revealing conclusions obtained from such model may be used for intervening in and modernising company activity.

  4. Dynamic Analysis of a Pendulum Dynamic Automatic Balancer

    Directory of Open Access Journals (Sweden)

    Jin-Seung Sohn

    2007-01-01

    Full Text Available The automatic dynamic balancer is a device to reduce the vibration from unbalanced mass of rotors. Instead of considering prevailing ball automatic dynamic balancer, pendulum automatic dynamic balancer is analyzed. For the analysis of dynamic stability and behavior, the nonlinear equations of motion for a system are derived with respect to polar coordinates by the Lagrange's equations. The perturbation method is applied to investigate the dynamic behavior of the system around the equilibrium position. Based on the linearized equations, the dynamic stability of the system around the equilibrium positions is investigated by the eigenvalue analysis.

  5. Molecular dynamics simulation: a tool for exploration and discovery using simple models

    Science.gov (United States)

    Rapaport, D. C.

    2014-12-01

    Emergent phenomena share the fascinating property of not being obvious consequences of the design of the system in which they appear. This characteristic is no less relevant when attempting to simulate such phenomena, given that the outcome is not always a foregone conclusion. The present survey focuses on several simple model systems that exhibit surprisingly rich emergent behavior, all studied by molecular dynamics (MD) simulation. The examples are taken from the disparate fields of fluid dynamics, granular matter and supramolecular self-assembly. In studies of fluids modeled at the detailed microscopic level using discrete particles, the simulations demonstrate that complex hydrodynamic phenomena in rotating and convecting fluids—the Taylor-Couette and Rayleigh-Bénard instabilities—can not only be observed within the limited length and time scales accessible to MD, but even allow quantitative agreement to be achieved. Simulation of highly counter-intuitive segregation phenomena in granular mixtures, again using MD methods, but now augmented by forces producing damping and friction, leads to results that resemble experimentally observed axial and radial segregation in the case of a rotating cylinder and to a novel form of horizontal segregation in a vertically vibrated layer. Finally, when modeling self-assembly processes analogous to the formation of the polyhedral shells that package spherical viruses, simulation of suitably shaped particles reveals the ability to produce complete, error-free assembly and leads to the important general observation that reversible growth steps contribute to the high yield. While there are limitations to the MD approach, both computational and conceptual, the results offer a tantalizing hint of the kinds of phenomena that can be explored and what might be discovered when sufficient resources are brought to bear on a problem.

  6. EKC: Static or Dynamic?

    OpenAIRE

    Dinda, Soumyananda

    2006-01-01

    This paper tests the robustness of the Environmental Kuznets Curve (EKC) hypothesis, using dynamic model specification for the long panel data set rather than static model. The monotonic income - CO2 emission relationship exists in most of the under developed or developing economies but EKC exists mostly in developed economies.

  7. Stochastic Switching Dynamics

    DEFF Research Database (Denmark)

    Simonsen, Maria

    mode control. It is investigated how to understand and interpret solutions to models of switched systems, which are exposed to discontinuous dynamics and uncertainties (primarily) in the form of white noise. The goal is to gain knowledge about the performance of the system by interpreting the solution...

  8. Dynamic Systems Modeling

    Directory of Open Access Journals (Sweden)

    Sorin Dan ŞANDOR

    2003-01-01

    Full Text Available System Dynamics was introduced by Jay W. Forrester in the 1960s. Since then the methodology was adopted in many areas of natural or social sciences. This article tries to present briefly how this methodology works, both as Systems Thinking and as Modelling with Vensim computer software.

  9. Dynamics of human movement

    NARCIS (Netherlands)

    Koopman, Hubertus F.J.M.

    2010-01-01

    The part of (bio)mechanics that studies the interaction of forces on the human skeletal system and its effect on the resulting movement is called rigid body dynamics. Some basic concepts are presented: A mathematical formulation to describe human movement and how this relates on the mechanical loads

  10. Modeling Climate Dynamically

    Science.gov (United States)

    Walsh, Jim; McGehee, Richard

    2013-01-01

    A dynamical systems approach to energy balance models of climate is presented, focusing on low order, or conceptual, models. Included are global average and latitude-dependent, surface temperature models. The development and analysis of the differential equations and corresponding bifurcation diagrams provides a host of appropriate material for…

  11. Dynamic Planar Convex Hull

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølfting; Jacob, Rico

    2002-01-01

    In this paper we determine the computational complexity of the dynamic convex hull problem in the planar case. We present a data structure that maintains a finite set of n points in the plane under insertion and deletion of points in amortized O(log n) time per operation. The space usage of the d...

  12. Dynamic Systems and Software

    DEFF Research Database (Denmark)

    Thomsen, Per Grove

    1996-01-01

    A one-dimensional model with axial discretization of engine components has been formulated using tha balance equations for mass energy and momentum and the ideal gas equation of state. ODE's that govern the dynamic behaviour of the regenerator matrix temperatures are included in the model. Known ...

  13. The Dynamics of Shape

    CERN Document Server

    Gomes, Henrique

    2011-01-01

    This thesis consists of two parts, connected by one central theme: the dynamics of the "shape of space". The first part of the thesis concerns the construction of a theory of gravity dynamically equivalent to general relativity (GR) in 3+1 form (ADM). What is special about this theory is that it does not possess foliation invariance, as does ADM. It replaces that "symmetry" by another: local conformal invariance. In so doing it more accurately reflects a theory of the "shape of space", giving us reason to call it \\emph{shape dynamics} (SD). In the first part we will try to present some of the highlights of results so far, and indicate what we can and cannot do with shape dynamics. Because this is a young, rapidly moving field, we have necessarily left out some interesting new results which are not yet in print and were developed alongside the writing of the thesis. The second part of the thesis will develop a gauge theory for "shape of space"--theories. To be more precise, if one admits that the physically re...

  14. Overeducation Dynamics and Personality

    Science.gov (United States)

    Blazquez, Maite; Budria, Santiago

    2012-01-01

    In this paper, we use the 2000-2008 waves of the German Socioeconomic Panel to examine overeducation transitions. The results are based on a first-order Markov model that allows us to account for both the initial conditions problem and potential endogeneity in attrition. We found that overeducation dynamics, especially the probability of entering…

  15. Ansatz for dynamical hierarchies

    DEFF Research Database (Denmark)

    Rasmussen, S.; Baas, N.A.; Mayer, B.

    2001-01-01

    the importance of this particular kind of organization for living systems. We then define a framework that enables us to formulate, investigate, and manipulate such dynamical hierarchies. This framework allows us to simultaneously investigate different levels of description together with them interrelationship...

  16. The dynamics of awareness

    NARCIS (Netherlands)

    van Benthem, J.; Velázquez-Quesada, F.R.

    2010-01-01

    Classical epistemic logic describes implicit knowledge of agents about facts and knowledge of other agents based on semantic information. The latter is produced by acts of observation or communication that are described well by dynamic epistemic logics. What these logics do not describe, however, is

  17. Regional Population Dynamics

    Science.gov (United States)

    Andrew Birt

    2011-01-01

    The population dynamics of the southern pine beetle (SPB) exhibit characteristic fluctuations between relatively long endemic and shorter outbreak periods. Populations exhibit complex and hierarchical spatial structure with beetles and larvae aggregating within individual trees, infestations with multiple infested trees, and regional outbreaks that comprise a large...

  18. Models for Dynamic Applications

    DEFF Research Database (Denmark)

    Sales-Cruz, Mauricio; Morales Rodriguez, Ricardo; Heitzig, Martina

    2011-01-01

    This chapter covers aspects of the dynamic modelling and simulation of several complex operations that include a controlled blending tank, a direct methanol fuel cell that incorporates a multiscale model, a fluidised bed reactor, a standard chemical reactor and finally a polymerisation reactor. T...

  19. Topics in Nonlinear Dynamics

    DEFF Research Database (Denmark)

    Mosekilde, Erik

    Through a significant number of detailed and realistic examples this book illustrates how the insights gained over the past couple of decades in the fields of nonlinear dynamics and chaos theory can be applied in practice. Aomng the topics considered are microbiological reaction systems, ecological...

  20. Representation in dynamical agents.

    Science.gov (United States)

    Ward, Ronnie; Ward, Robert

    2009-04-01

    This paper extends experiments by Beer [Beer, R. D. (1996). Toward the evolution of dynamical neural networks for minimally cognitive behavior. In P. Maes, M. Mataric, J. Meyer, J. Pollack, & S. Wilson (Eds.), From animals to animats 4: Proceedings of the fourth international conference on simulation of adaptive behavior (pp. 421-429). MIT Press; Beer, R. D. (2003). The dynamics of active categorical perception in an evolved model agent (with commentary and response). Adaptive Behavior, 11 (4), 209-243] with an evolved, dynamical agent to further explore the question of representation in cognitive systems. Beer's environmentally-situated visual agent was controlled by a continuous-time recurrent neural network, and evolved to perform a categorical perception task, discriminating circles from diamonds. Despite the agent's high levels of discrimination performance, Beer found no evidence of internal representation in the best-evolved agent's nervous system. Here we examine the generality of this result. We evolved an agent for shape discrimination, and performed extensive behavioral analyses to test for representation. In this case we find that agents developed to discriminate equal-width shapes exhibit what Clark [Clark, A. (1997). The dynamical challenge. Cognitive Science, 21 (4), 461-481] calls "weak-substantive representation". The agent had internal configurations that (1) were understandably related to the object in the environment, and (2) were functionally used in a task relevant way when the target was not visible to the agent.

  1. Dynamic update with probabilities

    NARCIS (Netherlands)

    Van Benthem, Johan; Gerbrandy, Jelle; Kooi, Barteld

    2009-01-01

    Current dynamic-epistemic logics model different types of information change in multi-agent scenarios. We generalize these logics to a probabilistic setting, obtaining a calculus for multi-agent update with three natural slots: prior probability on states, occurrence probabilities in the relevant

  2. Dynamics of Information Systems

    CERN Document Server

    Hirsch, Michael J; Murphey, Robert

    2010-01-01

    Our understanding of information and information dynamics has outgrown classical information theory. This book presents the research explaining the importance of information in the evolution of a distributed or networked system. It presents techniques for measuring the value or significance of information within the context of a system

  3. Dynamic term structure models

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller; Meldrum, Andrew

    This paper studies whether dynamic term structure models for US nominal bond yields should enforce the zero lower bound by a quadratic policy rate or a shadow rate specification. We address the question by estimating quadratic term structure models (QTSMs) and shadow rate models with at most four...

  4. Electronic Spectroscopy & Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Mark Maroncelli, Nancy Ryan Gray

    2010-06-08

    The Gordon Research Conference (GRC) on Electronic Spectroscopy and Dynamics was held at Colby College, Waterville, NH from 07/19/2009 thru 07/24/2009. The Conference was well-attended with participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. The GRC on Electronic Spectroscopy & Dynamics showcases some of the most recent experimental and theoretical developments in electronic spectroscopy that probes the structure and dynamics of isolated molecules, molecules embedded in clusters and condensed phases, and bulk materials. Electronic spectroscopy is an important tool in many fields of research, and this GRC brings together experts having diverse backgrounds in physics, chemistry, biophysics, and materials science, making the meeting an excellent opportunity for the interdisciplinary exchange of ideas and techniques. Topics covered in this GRC include high-resolution spectroscopy, biological molecules in the gas phase, electronic structure theory for excited states, multi-chromophore and single-molecule spectroscopies, and excited state dynamics in chemical and biological systems.

  5. The Dynamics of Information

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    efficacy at making predictions in the real world. About the speaker Bernardo Huberman is a Senior HP Fellow and Director of the Information Dynamics Lab at Hewlett Packard Laboratories. He received his Ph.D. in Physics from the University of Pennsylvania, and is currently a Consulting Professor in the Department of Applied Physics at Stanford University...

  6. Dynamical Imaging with Interferometry

    Science.gov (United States)

    Johnson, Michael D.; Bouman, Katherine L.; Blackburn, Lindy; Chael, Andrew A.; Rosen, Julian; Shiokawa, Hotaka; Roelofs, Freek; Akiyama, Kazunori; Fish, Vincent L.; Doeleman, Sheperd S.

    2017-12-01

    By linking widely separated radio dishes, the technique of very long baseline interferometry (VLBI) can greatly enhance angular resolution in radio astronomy. However, at any given moment, a VLBI array only sparsely samples the information necessary to form an image. Conventional imaging techniques partially overcome this limitation by making the assumption that the observed cosmic source structure does not evolve over the duration of an observation, which enables VLBI networks to accumulate information as Earth rotates and changes the projected array geometry. Although this assumption is appropriate for nearly all VLBI, it is almost certainly violated for submillimeter observations of the Galactic center supermassive black hole, Sagittarius A* (Sgr A*), which has a gravitational timescale of only ∼ 20 s and exhibits intrahour variability. To address this challenge, we develop several techniques to reconstruct dynamical images (“movies”) from interferometric data. Our techniques are applicable to both single-epoch and multiepoch variability studies, and they are suitable for exploring many different physical processes including flaring regions, stable images with small time-dependent perturbations, steady accretion dynamics, or kinematics of relativistic jets. Moreover, dynamical imaging can be used to estimate time-averaged images from time-variable data, eliminating many spurious image artifacts that arise when using standard imaging methods. We demonstrate the effectiveness of our techniques using synthetic observations of simulated black hole systems and 7 mm Very Long Baseline Array observations of M87, and we show that dynamical imaging is feasible for Event Horizon Telescope observations of Sgr A*.

  7. Dynamics via measurability

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available Generators f for σ -algebras can be used to view the dynamics of an invertible measurable transformation T in terms of the range values of f ∘ T . Such generators are the norm rather than the exception. Related measurable and quantitative methods of estimating a function from the behavior of ergodic averages are also discussed.

  8. Designing Dynamic Atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2012-01-01

    This paper addresses the notion of atmospheres from a designerly perspective, and discusses temporal challenges facing interaction designers when acknowledging the dynamic character of it. As atmospheres are created in the relation between body, space, and time, a pragmatic approach seems useful....... The potentials and implications are presented through a design case, Kidkit, highlighting temporality as design parametre within interaction design....

  9. Supervision and group dynamics

    DEFF Research Database (Denmark)

    Hansen, Søren; Jensen, Lars Peter

    2004-01-01

     An important aspect of the problem based and project organized study at Aalborg University is the supervision of the project groups. At the basic education (first year) it is stated in the curriculum that part of the supervisors' job is to deal with group dynamics. This is due to the experience ...

  10. Dynamic Contingency Analysis Tool

    Energy Technology Data Exchange (ETDEWEB)

    2016-01-14

    The Dynamic Contingency Analysis Tool (DCAT) is an open-platform and publicly available methodology to help develop applications that aim to improve the capabilities of power system planning engineers to assess the impact and likelihood of extreme contingencies and potential cascading events across their systems and interconnections. Outputs from the DCAT will help find mitigation solutions to reduce the risk of cascading outages in technically sound and effective ways. The current prototype DCAT implementation has been developed as a Python code that accesses the simulation functions of the Siemens PSS/E planning tool (PSS/E). It has the following features: It uses a hybrid dynamic and steady-state approach to simulating the cascading outage sequences that includes fast dynamic and slower steady-state events. It integrates dynamic models with protection scheme models for generation, transmission, and load. It models special protection systems (SPSs)/remedial action schemes (RASs) and automatic and manual corrective actions. Overall, the DCAT attempts to bridge multiple gaps in cascading-outage analysis in a single, unique prototype tool capable of automatically simulating and analyzing cascading sequences in real systems using multiprocessor computers.While the DCAT has been implemented using PSS/E in Phase I of the study, other commercial software packages with similar capabilities can be used within the DCAT framework.

  11. Dynamic Displays of Data

    Science.gov (United States)

    Angotti, Robin

    2017-01-01

    This article describes Gapminder, a dynamic time-series graph that can be found at http://www.gapminder.org. Gapminder was created by a team of developers (Rosling, Ronnlund, and Rosling 2005) to create beautiful, interactive graphs of otherwise lifeless numbers. Their goal is increased use and understanding of statistics and data that…

  12. Macroevolution: dynamics of diversity.

    Science.gov (United States)

    Erwin, Douglas H

    2011-12-20

    The fossil record typically exhibits very dynamic patterns of innovation, diversification and extinction. In contrast, molecular phylogenies suggest smoother patterns of evolutionary change. Several new studies reconcile this difference and reveal more about the mechanisms behind macroevolutionary change. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Unemployment Dynamics and Age

    NARCIS (Netherlands)

    Berg, van den G.J.; Gijsbert, A.; Lomwel, van C.; Ours, van Jan C.

    1998-01-01

    Youth unemployment is an issue of primary concern in WesternEuropean countries. In this paper we analyze dynamics in unemployment foryouths, adults (prime-aged individuals), and elderly. We use quarterly Frenchunemployment data, stratified by gender, age group, and duration, over theperiod

  14. Arctic avalanche dynamics

    Science.gov (United States)

    Prokop, Alexander; Eiken, Mari; Ganaus, Kerstin; Rubensdotter, Lena

    2017-04-01

    Since the avalanche disaster December 19th, 2015 in Longyearbyen (Svalbard) happened, where two people were killed within settlements, the dynamic of avalanches in arctic regions is of increasing interest for hazard mapping in such areas. To investigate the flow behavior of arctic avalanches we focused on avalanches that occurred in Central Svalbard. In this regions historic avalanche events can be analyzed due to their deposition behavior visible on geomorphological maps in the run-out area of the avalanches. To get an idea about possible snow mass that was involved in the avalanches we measured the snow volume balance of recent avalanches (winters 2015/16) via terrestrial laser scanning. In this way we gained reasonable data to set calibration and input parameters for dynamic avalanche modeling. Using state of the art dynamic avalanche models allowed us to back calculate how much snow was involved in the historic avalanches that we identified on the geomorphological maps and what the return period of those events are. In our presentation we first explain our methodology; we discuss arctic avalanche behavior of the avalanches measured via terrestrial laser scanning and how the dynamic avalanche models performed for those case examples. Finally we conclude how our results can improve avalanche hazard mapping for arctic regions.

  15. Effective relational dynamics

    NARCIS (Netherlands)

    Höhn, P.A.

    2011-01-01

    We provide a synopsis of an effective approach to the problem of time in the semiclassical regime. The essential features of this new approach to evaluating relational quantum dynamics in constrained systems are illustrated by means of a simple toy model.

  16. Scientists Probe Pesticide Dynamics

    Science.gov (United States)

    Chemical and Engineering News, 1974

    1974-01-01

    Summarizes discussions of a symposium on pesticide environmental dynamics with emphases upon pesticide transport processes, environmental reactions, and partitioning in air, soil, water and living organisms. Indicates that the goal is to attain knowledge enough to predict pesticide behavior and describe pesticide distribution with models and…

  17. ESSENTIAL DYNAMICS OF PROTEINS

    NARCIS (Netherlands)

    AMADEI, A; LINSSEN, ABM; BERENDSEN, HJC

    1993-01-01

    Analysis of extended molecular dynamics (MD) simulations of lysozyme in vacuo and in aqueous solution reveals that it is possible to separate the configurational space into two subspaces: (1) an ''essential'' subspace containing only a few degrees of freedom in which anharmonic motion occurs that

  18. Dynamic Nanoparticles Assemblies

    Science.gov (United States)

    WANG, LIBING; XU, LIGUANG; KUANG, HUA; XU, CHUANLAI; KOTOV, NICHOLAS A.

    2012-01-01

    CONSPECTUS Importance Although nanoparticle (NP) assemblies are at the beginning of their development, their unique geometrical shapes and media-responsive optical, electronic and magnetic properties have attracted significant interest. Nanoscale assembly bridges multiple sizes of materials: individual nanoparticles, discrete molecule-like or virus-like nanoscale agglomerates, microscale devices, and macroscale materials. The capacity to self-assemble can greatly facilitate the integration of nanotechnology with other technologies and, in particular, with microscale fabrication. In this Account, we describe developments in the emerging field of dynamic NP assemblies, which are spontaneously formed superstructures containing more than two inorganic nanoscale particles that display ability to change their geometrical, physical, chemical, and other attributes. In many ways, dynamic assemblies can represent a bottleneck in the ‘bottom-up’ fabrication of NP-based devices because they can produce a much greater variety of assemblies, but they also provide a convenient tool for variation of geometries and dimensions of nanoparticle assemblies. Classification Superstructures of NPs (and those held together by similar intrinsic forces) are classified into two groups: Class 1 where media and external fields can alter shape, conformation, and order of stable superstructures with a nearly constant number same. The future development of successful dynamic assemblies requires understanding the equilibrium in dynamic NP systems. The dynamic nature of Class 1 assemblies is associated with the equilibrium between different conformations of a superstructure and is comparable to the isomerization in classical chemistry. Class 2 assemblies involve the formation and/or breakage of linkages between the NPs, which is analogous to the classical chemical equilibrium for the formation of a molecule from atoms. Finer classification of NP assemblies in accord with established conventions

  19. Dynamic nanoparticle assemblies.

    Science.gov (United States)

    Wang, Libing; Xu, Liguang; Kuang, Hua; Xu, Chuanlai; Kotov, Nicholas A

    2012-11-20

    Although nanoparticle (NP) assemblies are at the beginning of their development, their unique geometrical shapes and media-responsive optical, electronic, and magnetic properties have attracted significant interest. Nanoscale assembly bridges multiple levels of hierarchy of materials: individual nanoparticles, discrete molecule-like or virus-like nanoscale agglomerates, microscale devices, and macroscale materials. The capacity to self-assemble can greatly facilitate the integration of nanotechnology with other technologies and, in particular, with microscale fabrication. In this Account, we describe developments in the emerging field of dynamic NP assemblies, which are spontaneously form superstructures containing more than two inorganic nanoscale particles that display the ability to change their geometrical, physical, chemical, and other attributes. In many ways, dynamic assemblies can represent a bottleneck in the "bottom-up" fabrication of NP-based devices because they can produce a much greater variety of assemblies, but they also provide a convenient tool for variation of geometries and dimensions of nanoparticle assemblies. Superstructures of NPs (and those held together by similar intrinsic forces)are classified into two groups: Class 1 where media and external fields can alter shape, conformation, and order of stable super structures with a nearly constant number of NPs or Class 2 where the total number of NPs changes, while the organizational motif in the final superstructure remains the same. The future development of successful dynamic assemblies requires understanding the equilibrium in dynamic NP systems. The dynamic nature of Class 1 assemblies is associated with the equilibrium between different conformations of a superstructure and is comparable to the isomerization in classical chemistry. Class 2 assemblies involve the formation or breakage of linkages between the NPs, which is analogous to the classical chemical equilibrium for the formation of

  20. Gravitomagnetic dynamical friction

    Science.gov (United States)

    Cashen, Benjamin; Aker, Adam; Kesden, Michael

    2017-03-01

    A supermassive black hole moving through a field of stars will gravitationally scatter the stars, inducing a backreaction force on the black hole known as dynamical friction. In Newtonian gravity, the axisymmetry of the system about the black hole's velocity v implies that the dynamical friction must be antiparallel to v . However, in general relativity the black hole's spin S need not be parallel to v , breaking the axisymmetry of the system and generating a new component of dynamical friction similar to the Lorentz force F =q v ×B experienced by a particle with charge q moving in a magnetic field B . We call this new force gravitomagnetic dynamical friction and calculate its magnitude for a spinning black hole moving through a field of stars with Maxwellian velocity dispersion σ , assuming that both v and σ are much less than the speed of light c . We use post-Newtonian equations of motion accurate to O (v3/c3) needed to capture the effect of spin-orbit coupling and also include direct stellar capture by the black hole's event horizon. Gravitomagnetic dynamical friction will cause a black hole with uniform speed to spiral about the direction of its spin, similar to a charged particle spiraling about a magnetic field line, and will exert a torque on a supermassive black hole orbiting a galactic center, causing the angular momentum of this orbit to slowly precess about the black hole spin. As this effect is suppressed by a factor (σ /c )2 in nonrelativistic systems, we expect it to be negligible in most astrophysical contexts but provide this calculation for its theoretical interest and potential application to relativistic systems.

  1. Dynamic stiffness of suction caissons

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Liingaard, Morten; Andersen, Lars

    The purpose of this report is to evaluate the dynamic soil-structure interaction of suction caissons for offshore wind turbines. The investigation is limited to a determination of the vertical dynamic stiffness of suction caissons. The soil surrounding the foundation is homogenous with linear...... viscoelastic properties. The dynamic stiffness of the suction caisson is expressed by dimensionless frequency-dependent dynamic stiffness coefficients corresponding to the vertical degree of freedom. The dynamic stiffness coefficients for the foundations are evaluated by means of a dynamic three...

  2. Explicit Dynamic DDA Method considering Dynamic Contact Force

    Directory of Open Access Journals (Sweden)

    Jian Zhao

    2016-01-01

    Full Text Available This paper proposes an explicit dynamic DDA method considering dynamic contact force, which aims at solving the problems of low efficiency of dynamic contact detection and the simulation of dynamic contact force in the conventional DDA method. The mutual contact between blocks can be regarded as the application of point loading on a single block, and the corresponding contact submatrix can be calculated and the simultaneous equations of the block system can be integrated. The central difference method is adopted to deduce the explicit expression of block displacement containing dynamic contact force. With the relationship between displacement and dynamic contact force, contact constraint equations of a block system are obtained to calculate the dynamic contact force and the corresponding block displacement. The accuracy of the explicit dynamic DDA method is verified using two numerical cases. The calculation results show that the new DDA method can be applied in large-scale geotechnical engineering.

  3. NVU dynamics. II. Comparing to four other dynamics

    DEFF Research Database (Denmark)

    Ingebrigtsen, Trond; Toxværd, Søren; Schrøder, Thomas

    2011-01-01

    -potential-energy hypersurface. Here, simulations of NVU dynamics are compared to results for four other dynamics, both deterministic and stochastic. First, NVU dynamics is compared to the standard energy-conserving Newtonian NVE dynamics by simulations of the Kob-Andersen binary Lennard-Jones liquid, its WCA version (i.......e., with cut-off's at the pair potential minima), and the Lennard-Jones Gaussian liquid. We find identical results for all quantities probed: radial distribution functions, incoherent intermediate scattering functions, and mean-square displacement as function of time. Arguments are presented...... on the constant-potential-energy hypersurface, and to Nos-Hoover NVT dynamics. If time is scaled for the two stochastic dynamics to make single-particle diffusion constants identical to that of NVE dynamics, the simulations show that all five dynamics are equivalent at low temperatures except at short times....

  4. Molecular dynamics simulation of a two-dimensional system

    Directory of Open Access Journals (Sweden)

    S. M. Huseini

    2001-06-01

    Full Text Available   The study of a two-dimensional (2-D system started nearly half a century ago when Peierls and Landau showed the lack of long range translational order in a two-dimensional solid. In 1968, Mermin proved that despite the absence of long range translational order. Two-dimensional solids can still exhibit a different kind of long range bond orientation. During the last decade, fascinating theories were put forward to explain the role of topological defects in the melting of two-dimensional solids, starting with Kosterlitz and Thouless. Recent surge of interest in melting is also due to the theoretical ideas of Halperin, Nelson and Young. They have suggested that the transition may be fundamentally different from that observed in ordinary three-dimensional systems. Computer simulations suggest that the transition is of the usual first-order type observed in a three-dimensional system. A large body of experimental and simulation research into the two-dimensional melting followed the announcement of the KTHNY theory. In spite of all this effort, the question as to the nature of two dimensional melting remains unresolved. Recent experimental work supporting the existence of continuous melting transitions in some two-dimentsional systems indicates the need for further theoretical and computational work to lead to an understanding of the experimental results.   In this paper we intend to summarze and clarify the current situation with regard to research in the two-dimensional melting with an emphasis on computer simulations. The paper begins with an overview of the current status of relevant theoretical, experimental and simulation research, then a two-dimensional simulation of an ionic salt system is studied in detail. This simulation has been done by using the molecular dynamics method. The most important parameters that have been determined are ,The trnsition temperature, the total energy of the system, the mean square displacement and the bond

  5. Growth of nanocomposite films : From dynamic roughening to dynamic smoothening

    NARCIS (Netherlands)

    Pei, Y.T.; Shaha, K.P.; Chen, C.Q.; van der Hulst, Ruben; Turkin, A; Vainshtein, D.I.; Hosson, J.Th.M. De

    2009-01-01

    This paper reports several new findings on the breakdown of dynamic roughening in thin film growth. With increasing energy flux of concurrent ion impingement during pulsed DC sputtering, a transition from dynamic roughening to dynamic smoothening is observed in the growth behavior of TiC/a-C

  6. Nonlinear Dynamic Model Explains The Solar Dynamic

    Science.gov (United States)

    Kuman, Maria

    Nonlinear mathematical model in torus representation describes the solar dynamic. Its graphic presentation shows that without perturbing force the orbits of the planets would be circles; only perturbing force could elongate the circular orbits into ellipses. Since the Hubble telescope found that the planetary orbits of other stars in the Milky Way are also ellipses, powerful perturbing force must be present in our galaxy. Such perturbing force is the Sagittarius Dwarf Galaxy with its heavy Black Hole and leftover stars, which we see orbiting around the center of our galaxy. Since observations of NASA's SDO found that magnetic fields rule the solar activity, we can expect when the planets align and their magnetic moments sum up, the already perturbed stars to reverse their magnetic parity (represented graphically as periodic looping through the hole of the torus). We predict that planets aligned on both sides of the Sun, when their magnetic moments sum-up, would induce more flares in the turbulent equatorial zone, which would bulge. When planets align only on one side of the Sun, the strong magnetic gradient of their asymmetric pull would flip the magnetic poles of the Sun. The Sun would elongate pole-to-pole, emit some energy through the poles, and the solar activity would cease. Similar reshaping and emission was observed in stars called magnetars and experimentally observed in super-liquid fast-spinning Helium nanodroplets. We are certain that NASA's SDO will confirm our predictions.

  7. Nonlinear dynamics: Challenges and perspectives

    Indian Academy of Sciences (India)

    . Nonlinear .... engineering problems as well as population dynamics, economics, social dynamics, etc. [11]. 2.1 Nonlinear ordinary ..... niques such as dispersion management method have been developed. Multina- tional organizations have ...

  8. Dynamic Hedging in Currency Crisis

    OpenAIRE

    Malte Krüger

    1998-01-01

    Garber and Spencer have argued that dynamic hedging may lead to perverse results when interest rates are used to defend an exchange rate. This paper shows that interest rate changes have little effects on dynamic hedgers when volatility is high.

  9. Nonlinear Dynamics in Ventricular Fibrillation

    National Research Council Canada - National Science Library

    Harold M. Hastings; Steven J. Evans; Weilun Quan; Martha L. Chong; Obi Nwasokwa

    1996-01-01

    .... Motivated by the work of Sugihara on atmospheric dynamics and the Durbin--Watson test for nonlinearity, we introduce a new statistical test that recovers significant dynamical patterns from smoothed lag plots...

  10. Homegarden Dynamics in Kerala, India

    NARCIS (Netherlands)

    Peyre, A.; Guidal, A.; Wiersum, K.F.; Bongers, F.J.J.M.

    2006-01-01

    The study of structural and functional dynamics of homegardens offers an opportunity to understand the trends in socioeconomic sustainability in relation to their ecological sustainability. These dynamics were studied in a survey of 30 homegardens

  11. Spin Glasses : Statics and Dynamics : Summer School

    CERN Document Server

    Bovier, Anton

    2009-01-01

    Over the last decade, spin glass theory has turned from a fascinating part of t- oretical physics to a ?ourishing and rapidly growing subject of probability theory as well. These developments have been triggered to a large part by the mathem- ical understanding gained on the fascinating and previously mysterious “Parisi solution” of the Sherrington–Kirkpatrick mean ?eld model of spin glasses, due to the work of Guerra, Talagrand, and others. At the same time, new aspects and applications of the methods developed there have come up. The presentvolumecollects a number of reviewsaswellas shorterarticlesby lecturers at a summer school on spin glasses that was held in July 2007 in Paris. These articles range from pedagogical introductions to state of the art papers, covering the latest developments. In their whole, they give a nice overview on the current state of the ?eld from the mathematical side. The review by Bovier and Kurkova gives a concise introduction to mean ?eld models, starting with the Curie–...

  12. Dynamical Cluster Approximation

    Science.gov (United States)

    Fotso, H.; Yang, S.; Chen, K.; Pathak, S.; Moreno, J.; Jarrell, M.; Mikelsons, K.; Khatami, E.; Galanakis, D.

    The dynamical cluster approximation (DCA) is a method which systematically incorporates nonlocal corrections to the dynamical mean-field approximation. Here we present a pedagogical discussion of the DCA by describing it as a Φ-derivable coarse-graining approximation in k-space, which maps an infinite lattice problem onto a periodic finite-sized cluster embedded in a self-consistently determined effective medium. We demonstrate the method by applying it to the two-dimensional Hubbard model. From this application, we show evidences of the presence of a quantum critical point (QCP) at a finite doping underneath the superconducting dome. The QCP is associated with the second-order terminus of a line of first order phase separation transitions. This critical point is driven to zero temperature by varying the band parameters, generating the QCP. The effect of the proximity of the QCP to the superconducting dome is also discussed.

  13. Signaling dynamics and peroxisomes.

    Science.gov (United States)

    Mast, Fred D; Rachubinski, Richard A; Aitchison, John D

    2015-08-01

    Peroxisomes are remarkably responsive organelles. Their composition, abundance and even their mechanism of biogenesis are influenced strongly by cell type and the environment. This plasticity underlies peroxisomal functions in metabolism and the detoxification of dangerous reactive oxygen species. However, peroxisomes are integrated into the cellular system as a whole such that they communicate intimately with other organelles, control signaling dynamics as in the case of innate immune responses to infectious disease, and contribute to processes as fundamental as longevity. The increasing evidence for peroxisomes having roles in various cellular and organismal functions, combined with their malleability, suggests complex mechanisms operate to control cellular dynamics and the specificity of cellular responses and functions extending well beyond the peroxisome itself. A deeper understanding of the functions of peroxisomes and the mechanisms that control their plasticity could offer opportunities for exploiting changes in peroxisome abundance to control cellular function. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Metaheuristics for Dynamic Optimization

    CERN Document Server

    Nakib, Amir; Siarry, Patrick

    2013-01-01

    This book is an updated effort in summarizing the trending topics and new hot research lines in solving dynamic problems using metaheuristics. An analysis of the present state in solving complex problems quickly draws a clear picture: problems that change in time, having noise and uncertainties in their definition are becoming very important. The tools to face these problems are still to be built, since existing techniques are either slow or inefficient in tracking the many global optima that those problems are presenting to the solver technique. Thus, this book is devoted to include several of the most important advances in solving dynamic problems. Metaheuristics are the more popular tools to this end, and then we can find in the book how to best use genetic algorithms, particle swarm, ant colonies, immune systems, variable neighborhood search, and many other bioinspired techniques. Also, neural network solutions are considered in this book. Both, theory and practice have been addressed in the chapters of t...

  15. Granular dynamics during impact.

    Science.gov (United States)

    Nordstrom, K N; Lim, E; Harrington, M; Losert, W

    2014-06-06

    We study the impact of a projectile onto a bed of 3 mm grains immersed in an index-matched fluid. We vary the amount of prestrain on the sample, strengthening the force chains within the system. We find this affects only the prefactor of the linear depth-dependent term in the stopping force. We propose a simple model to account for the strain dependence of this term, owing to increased pressure in the pile. Interestingly, we find that the presence of the fluid does not affect the impact dynamics, suggesting that dynamic friction is not a factor. Using a laser sheet scanning technique to visualize internal grain motion, we measure the trajectory of each grain throughout an impact. Microscopically, our results indicate that weaker initial force chains result in more irreversible, plastic rearrangements, suggesting static friction between grains does play a substantial role in the energy dissipation.

  16. Dynamics and Relativity

    CERN Document Server

    Forshaw, Jeffrey

    2009-01-01

    A new title in the Manchester Physics Series, this introductory text emphasises physical principles behind classical mechanics and relativity. It assumes little in the way of prior knowledge, introducing relevant mathematics and carefully developing it within a physics context. Designed to provide a logical development of the subject, the book is divided into four sections, introductory material on dynamics, and special relativity, which is then followed by more advanced coverage of dynamics and special relativity. Each chapter includes problems ranging in difficulty from simple to challenging with?solutions for solving problems. Includes?solutions for solving problemsNumerous worked examples included throughout the bookMathematics is carefully explained and developed within a physics environmentSensitive to topics that can appear daunting or confusing

  17. Dynamic Global Currency Hedging

    DEFF Research Database (Denmark)

    Christensen, Bent Jesper; Varneskov, Rasmus T.

    2016-01-01

    This paper proposes a model for discrete-time hedging based on continuous-time movements in portfolio and foreign currency exchange rate returns. In particular, the vector of optimal currency exposures is shown to be given by the negative realized regression coefficients from a one......-period conditional expectation of the intra-period quadratic covariation matrix for portfolio and foreign exchange rate returns. These are labelled the realized currency betas. The model, hence, facilitates dynamic hedging strategies that depend exclusively on the dynamic evolution of the ex-post quadratic...... that the realized currency betas exhibit important time variation, leading to substantial economic, as well as statistically significant, volatility reductions from the proposed hedging strategies, compared to existing benchmarks, without sacrificing returns. As a result, a risk-averse investor is shown...

  18. Dynamical quark mass generation

    CERN Document Server

    Frezzotti, Roberto

    2013-01-01

    Taking inspiration from lattice QCD results, we argue that a non-perturbative mass term for fermions can be generated as a consequence of the dynamical phenomenon of spontaneous chiral symmetry breaking, in turn triggered by the explicitly breaking of chiral symmetry induced by the critical Wilson term in the action. In a pure lattice QCD-like theory this mass term cannot be separated from the unavoidably associated linearly divergent contribution. However, if QCD with a Wilson term is enlarged to a theory where also a scalar field is present, coupled to a doublet of SU(2) fermions via a Yukawa interaction, then in the phase where the scalar field takes a non-vanishing (large) expectation value, a dynamically generated and ``naturally'' light fermion mass (numerically unrelated to the expectation value of the scalar field) is seen to emerge, at a critical value of the Yukawa coupling where the symmetry of the model is maximally enhanced.

  19. Classical Dynamics of Fullerenes

    Science.gov (United States)

    Sławianowski, Jan J.; Kotowski, Romuald K.

    2017-06-01

    The classical mechanics of large molecules and fullerenes is studied. The approach is based on the model of collective motion of these objects. The mixed Lagrangian (material) and Eulerian (space) description of motion is used. In particular, the Green and Cauchy deformation tensors are geometrically defined. The important issue is the group-theoretical approach to describing the affine deformations of the body. The Hamiltonian description of motion based on the Poisson brackets methodology is used. The Lagrange and Hamilton approaches allow us to formulate the mechanics in the canonical form. The method of discretization in analytical continuum theory and in classical dynamics of large molecules and fullerenes enable us to formulate their dynamics in terms of the polynomial expansions of configurations. Another approach is based on the theory of analytical functions and on their approximations by finite-order polynomials. We concentrate on the extremely simplified model of affine deformations or on their higher-order polynomial perturbations.

  20. Dynamics of Catalyst Nanoparticles

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Cavalca, Filippo; Wagner, Jakob Birkedal

    under gas exposure, dynamic phenomena such as sintering and growth can be observed with sub-Ångstrøm resolution. Metal nanoparticles contain the active sites in heterogeneous catalysts, which are important for many industrial applications including the production of clean fuels, chemicals...... and pharmaceuticals, and the cleanup of exhaust from automobiles and stationary power plants. Sintering, or thermal deactivation, is an important mechanism for the loss of catalyst activity. In order to initiate a systematic study of the dynamics and sintering of nanoparticles, various catalytic systems have been...... that particle sintering is not solely governed by the mechanisms previously proposed. These results are divided into the different phases of the catalyst lifetime....