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Sample records for dominant cyclic hematopoiesis

  1. Autosomal dominant cyclic hematopoiesis: Genetics, phenotype, and natural history

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, S.E.; Stephens, K.; Dale, D.C. [Univ. of Washington, Seattle, WA (United States)

    1994-09-01

    Autosomal dominant cyclic hematopoiesis (ADCH; cyclic neutropenia) is a rare disorder manifested by transient neutropenia that recurs every three weeks. To facilitate mapping the ADCH gene by genetic linkage analysis, we studied 9 ADCH families with 42 affected individuals. Pedigrees revealed AD inheritance with no evidence for decreased penetrance. Similar intra- and interfamilial variable expression was observed, with no evidence to support heterogeneity. At least 3 families displayed apparent new mutations. Many adults developed chronic neutropenia, while offspring always cycled during childhood. Children displayed recurrent oral ulcers, gingivitis, lymphadenopathy, fever, and skin and other infections with additional symptoms. Interestingly, there were no cases of neonatal infection. Some children required multiple hospitalizations for treatment. Four males under age 18 died of Clostridium sepsis following necrotizing enterocolitis; all had affected mothers. No other deaths due to ADCH were found; most had improvement of symptoms and infections as adults. Adults experienced increased tooth loss prior to age 30 (16 out of 27 adults, with 9 edentulous). No increase in myelodysplasia, malignancy, or congenital anomalies was observed. Recombinant G-CSF treatment resulted in dramatic improvement of symptoms and infections. The results suggest that ADCH is not a benign disorder, especially in childhood, and abdominal pain requires immediate evaluation. Diagnosis of ADCH requires serial blood counts in the proband and at least one CBC in relatives to exclude similar disorders. Genetic counseling requires specific histories as well as CBCs of each family member at risk to determine status regardless of symptom history, especially to assess apparent new mutations.

  2. Zealotry promotes coexistence in the rock-paper-scissors model of cyclic dominance.

    Science.gov (United States)

    Verma, Gunjan; Chan, Kevin; Swami, Ananthram

    2015-11-01

    Cyclic dominance models, such as the classic rock-paper-scissors (RPS) game, have found real-world applications in biology, ecology, and sociology. A key quantity of interest in such models is the coexistence time, i.e., the time until at least one population type goes extinct. Much recent research has considered conditions that lengthen coexistence times in an RPS model. A general finding is that coexistence is promoted by localized spatial interactions (low mobility), while extinction is fostered by global interactions (high mobility). That is, there exists a mobility threshold which separates a regime of long coexistence from a regime of rapid collapse of coexistence. The key finding of our paper is that if zealots (i.e., nodes able to defeat others while themselves being immune to defeat) of even a single type exist, then system coexistence time can be significantly prolonged, even in the presence of global interactions. This work thus highlights a crucial determinant of system survival time in cyclic dominance models.

  3. Collective strategies and cyclic dominance in asymmetric predator-prey spatial games.

    Science.gov (United States)

    Cazaubiel, Annette; Lütz, Alessandra F; Arenzon, Jeferson J

    2017-10-07

    Predators may attack isolated or grouped prey in a cooperative, collective way. Whether a gregarious behavior is advantageous to each species depends on several conditions and game theory is a useful tool to deal with such a problem. We here extend the Lett et al. (2004) to spatially distributed populations and compare the resulting behavior with their mean-field predictions for the coevolving densities of predator and prey strategies. Besides its richer behavior in the presence of spatial organization, we also show that the coexistence phase in which collective and individual strategies for each group are present is stable because of an effective, cyclic dominance mechanism similar to a well-studied generalization of the Rock-Paper-Scissors game with four species, a further example of how ubiquitous this coexistence mechanism is. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. A Five Species Cyclically Dominant Evolutionary Game with Fixed Direction: A New Way to Produce Self-Organized Spatial Patterns

    Directory of Open Access Journals (Sweden)

    Yibin Kang

    2016-08-01

    Full Text Available Cyclically dominant systems are hot issues in academia, and they play an important role in explaining biodiversity in Nature. In this paper, we construct a five-strategy cyclically dominant system. Each individual in our system changes its strategy along a fixed direction. The dominant strategy can promote a change in the dominated strategy, and the dominated strategy can block a change in the dominant strategy. We use mean-field theory and cellular automaton simulation to discuss the evolving characters of the system. In the cellular automaton simulation, we find the emergence of spiral waves on spatial patterns without a migration rate, which suggests a new way to produce self-organized spatial patterns.

  5. Adaptive cyclically dominating game on co-evolving networks: numerical and analytic results

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    Choi, Chi Wun; Xu, Chen; Hui, Pak Ming

    2017-10-01

    A co-evolving and adaptive Rock (R)-Paper (P)-Scissors (S) game (ARPS) in which an agent uses one of three cyclically dominating strategies is proposed and studied numerically and analytically. An agent takes adaptive actions to achieve a neighborhood to his advantage by rewiring a dissatisfying link with a probability p or switching strategy with a probability 1 - p. Numerical results revealed two phases in the steady state. An active phase for p pc has three separate clusters of agents using only R, P, and S, respectively with terminated adaptive actions. A mean-field theory based on the link densities in co-evolving network is formulated and the trinomial closure scheme is applied to obtain analytical solutions. The analytic results agree with simulation results on ARPS well. In addition, the different probabilities of winning, losing, and drawing a game among the agents are identified as the origin of the small discrepancy between analytic and simulation results. As a result of the adaptive actions, agents of higher degrees are often those being taken advantage of. Agents with a smaller (larger) degree than the mean degree have a higher (smaller) probability of winning than losing. The results are informative for future attempts on formulating more accurate theories.

  6. Tachykinins and hematopoiesis.

    Science.gov (United States)

    Liu, Katherine; Castillo, Marianne D; Murthy, Raghav G; Patel, Nitixa; Rameshwar, Pranela

    2007-10-01

    Originally discovered in the 1930s, tachykinins have been a subject of renewed interest. Antagonists to the tachykinin receptors have shown potential in the treatment of a variety of maladies including neurodegenerative disorders, heart disease, pain perception and malignancies. Tachykinins have been the subject of intense studies due to their impact on hematopoiesis that has significant effects on endothelial tissue and vascular conditions. Hematopoiesis relies on a relatively small subset of bone marrow-resident hematopoietic stem cells. This review discusses the network developed by cytokines and the tachykinins to regulate hematopoiesis. An understanding of tachykinin effect on normal hematopoietic functions and their involvement in hematological disorders could lead to new treatments for bone marrow disorders such as fibrosis, leukemia and anemia.

  7. Centennial eolian cyclicity in the Great Plains, USA: A dominant pattern of wind transport over the past 4000 years?

    Science.gov (United States)

    Schwalb, Antje; Dean, Walter E.; Fritz, C. Sherilyn; Geiss, Christoph E.; Kromer, Bernd

    2010-01-01

    Proxy evidence at decadal resolution from Late Holocene sediments from Pickerel Lake, northeastern South Dakota, shows distinct centennial cycles (400-700 years) in magnetic susceptibility; contents of carbonate, organic carbon, and major elements; abundance in ostracodes; and delta18O and delta13C values in calcite. Proxies indicate cyclic changes in eolian input, productivity, and temperature. Maxima in magnetic susceptibility are accompanied by maxima in aluminum and iron mass accumulation rates (MARs), and in abundances of the ostracode Fabaeformiscandona rawsoni. This indicates variable windy, and dry conditions with westerly wind dominance, including during the Medieval Climate Anomaly. Maxima in carbonates, organic carbon, phosphorous, and high delta13C values of endogenic calcite indicate moister and less windy periods with increased lake productivity, including during the Little Ice Age, and alternate with maxima of eolian transport. Times of the Maunder, Sporer and Wolf sunspot minima are characterized by maxima in delta18O values and aluminum MARs, and minima in delta13C values and organic carbon content. We interpret these lake conditions during sunspot minima to indicate decreases in lake surface water temperatures of up to 4-5 degrees C associated with decreases in epilimnetic productivity during summer. We propose that the centennial cycles are triggered by solar activity, originate in the tropical Pacific, and their onset during the Late Holocene is associated with insolation conditions driven by precession. The cyclic pattern is transmitted from the tropical Pacific into the atmosphere and transported by westerly winds into the North Atlantic realm where they strengthen the Atlantic Meridional Overturning Circulation during periods of northern Great Plains wind maxima. This consequently leads to moister climates in Central and Northern Europe. Thus, Pickerel Lake provides evidence for mechanisms of teleconnections including an atmospheric link

  8. Focal splenic masses of the extramedullary hematopoiesis

    International Nuclear Information System (INIS)

    Incedayi, M.; Sivrioglu, A.

    2012-01-01

    Full text: Extramedullary hematopoiesis arises from pleuripotential stem cells distributed throughout the body. It is most common in patients with congenital hemolytic anemia, such as thalassemia, sickle cell anemia and hereditary spherocytosis as a response to ineffective red blood cell formation. Although microscopic foci of Extramedullary hematopoiesis are commonly seen in the spleen and liver parenchyma, focal mass-like lesion of extramedullary hematopoiesis in the liver and spleen are rare. We report a case of intrasplenic focal extramedullary hematopoiesis lesions and the imaging features of extramedullary hematopoiesis on computed tomography and magnetic resonance imaging. Extramedullary hematopoiesis should always be considered as a diagnosis in a patient with a known hematological disorder

  9. MRI features of epidural extramedullary hematopoiesis

    Energy Technology Data Exchange (ETDEWEB)

    Alorainy, Ibrahim A. E-mail: alorainy@ksu.edu.sa; Al-Asmi, Abdullah R.; Carpio, Raquel del

    2000-07-01

    A case of {beta}-thalassemia intermedia with spinal cord compression due to extramedullary hematopoiesis, which was successfully treated by blood transfusion, is presented. Emphasis was made on the MRI appearance of extramedullary hematopoiesis on different pulse sequences. The theories that aimed to explain the involvement of the epidural space by extramedullary hematopoiesis are discussed.

  10. Internal stress relaxation and load redistribution during the twinning-detwinning-dominated cyclic deformation of a wrought magnesium alloy, ZK60A

    International Nuclear Information System (INIS)

    Wu, L.; Agnew, S.R.; Brown, D.W.; Stoica, G.M.; Clausen, B.; Jain, A.; Fielden, D.E.; Liaw, P.K.

    2008-01-01

    A study of the internal strain (stress) evolution during cyclic deformation dominated by {101-bar2} twinning and detwinning mechanisms within a magnesium alloy, ZK60A, was conducted using in situ neutron diffraction. It is shown that once the matrix grains twin, the (00.2) matrix and twin grains are relaxed relative to the neighbors. This load redistribution between the soft- and hard-grain orientations is a result of plastic anisotropy. The twins which formed during the initial compression sustain a tensile stress along the c-axis, when the applied compressive stress is less than ∼80 MPa upon unloading. This local (intergranular) tensile stress is hypothesized to be effective for driving the detwinning event under a macroscopic compressive field along the c-axis. The activation stresses, 15 and 6 MPa, respectively, for the {101-bar2} extension twinning and detwinning, are approximated, based on the relaxation of the internal stresses in the matrix and twin grains

  11. Extramedullary hematopoiesis: A report of two cases.

    Science.gov (United States)

    Zhang, Huan-Zhu; Li, Ying; Liu, Xin; Chen, Bao-Rong; Yao, Guo-Hua; Peng, Yu-Na

    2016-12-01

    Extramedullary hematopoiesis (EMH) is defined as hematopoiesis occurring in organs outside of the bone marrow. The present report describes two cases of thalassemic patients with paraspinal medullary hematopoiesis and analyzes the clinical manifestations, imaging, pathology, diagnosis and treatment of EMH. In addition, a supplementary review of previously published cases is provided along with a review of the related literature. Computed tomography (CT) of the first case revealed multiple paraspinal masses, and the largest was 6.2×8.0 cm in diameter. Likewise, CT of the second patient revealed multiple paraspinal masses in the bottom of the left thoracic cavity, and the largest was measured 10.1×10.5 cm. The two cases underwent surgical biopsy and the findings were compatible with a diagnosis of EMH. In conclusion, EMH is a compatible and rare disease, and should be distinguished from other neoplasms. EMH must considered when masses with characteristic radiologic appearance are detected in patients with thalassemia intermedia.

  12. Mass-like extramedullary hematopoiesis: imaging features

    Energy Technology Data Exchange (ETDEWEB)

    Ginzel, Andrew W. [Synergy Radiology Associates, Houston, TX (United States); Kransdorf, Mark J.; Peterson, Jeffrey J.; Garner, Hillary W. [Mayo Clinic, Department of Radiology, Jacksonville, FL (United States); Murphey, Mark D. [American Institute for Radiologic Pathology, Silver Spring, MD (United States)

    2012-08-15

    To report the imaging appearances of mass-like extramedullary hematopoiesis (EMH), to identify those features that are sufficiently characteristic to allow a confident diagnosis, and to recognize the clinical conditions associated with EMH and the relative incidence of mass-like disease. We retrospectively identified 44 patients with EMH; 12 of which (27%) had focal mass-like lesions and formed the study group. The study group consisted of 6 male and 6 female subjects with a mean age of 58 years (range 13-80 years). All 12 patients underwent CT imaging and 3 of the 12 patients had undergone additional MR imaging. The imaging characteristics of the extramedullary hematopoiesis lesions in the study group were analyzed and recorded. The patient's clinical presentation, including any condition associated with extramedullary hematopoiesis, was also recorded. Ten of the 12 (83%) patients had one or more masses located along the axial skeleton. Of the 10 patients with axial masses, 9 (90%) had multiple masses and 7 (70%) demonstrated internal fat. Eight patients (80%) had paraspinal masses and 4 patients (40%) had presacral masses. Seven patients (70%) had splenomegaly. Eleven of the 12 patients had a clinical history available for review. A predisposing condition for extramedullary hematopoiesis was present in 10 patients and included various anemias (5 cases; 45%), myelofibrosis/myelodysplastic syndrome (4 cases; 36%), and marrow proliferative disorder (1 case; 9%). One patient had no known predisposing condition. Mass-like extramedullary hematopoiesis most commonly presents as multiple, fat-containing lesions localized to the axial skeleton. When these imaging features are identified, extramedullary hematopoiesis should be strongly considered, particularly when occurring in the setting of a predisposing medical condition. (orig.)

  13. Epigenetic Regulation of Hematopoiesis and Acute Leukemia

    NARCIS (Netherlands)

    D.G. Valerio (Daria)

    2017-01-01

    markdownabstractIn this thesis we have explored chromatin regulation in acute leukemia and normal hematopoiesis. In doing so, we have focused on the H3K4 methyltransferase MLL1 and the H4K16 acetyltransferase MOF. MLL- and NUP98-translocations are quite common in acute leukemia and even more

  14. Dissection of vertebrate hematopoiesis using zebrafish thrombopoietin

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Ondřej; Stachura, D.L.; Machoňová, Olga; Pajer, Petr; Brynda, Jiří; Zon, L.I.; Traver, D.; Bartůněk, Petr

    2014-01-01

    Roč. 124, č. 2 (2014), s. 220-228 ISSN 0006-4971 R&D Projects: GA ČR GAP305/10/0953 Grant - others:NIH(US) K01-DK087814-01A1; NIH(US) R01-DK074482 Keywords : Zebrafish * hematopoiesis * progenitors * thrombopoietin * erythropoietin Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 10.452, year: 2014

  15. Renal extramedullary hematopoiesis: interstitial and glomerular pathology.

    Science.gov (United States)

    Alexander, Mariam P; Nasr, Samih H; Kurtin, Paul J; Casey, Edward T; Hernandez, Loren P Herrera; Fidler, Mary E; Sethi, Sanjeev; Cornell, Lynn D

    2015-12-01

    Renal extramedullary hematopoiesis is rarely recognized in the antemortem setting. We identified 14 patients with renal extramedullary hematopoiesis on antemortem specimens from 1994 to 2015. The mean age was 68 years (range 47-87 years); males predominated (M:F=9:5). All presented with renal insufficiency, including five (36%) with acute kidney injury. The mean serum creatinine at biopsy was 2.9 mg/dl (range 1.2-7.3 mg/dl). All had proteinuria (mean 7.9 g/24 h; range 0.5-28; n=13), including 9 with ≥3 g/24 h. Renal extramedullary hematopoiesis appeared histologically as an interstitial infiltrate (n=12) and/or a perirenal infiltrate (n=3) or mass-like lesion (n=1). Five were misdiagnosed as interstitial nephritis. Concurrent glomerular disease was prevalent and included fibrillary-like glomerulonephritis (n=3), chronic thrombotic microangiopathy (n=5), focal segmental glomerulosclerosis (n=6), and diabetic glomerulosclerosis (n=2). All patients had an underlying hematologic malignancy: primary myelofibrosis in 9, myeloproliferative neoplasm not otherwise specified in 1, essential thrombocythemia in 1, polycythemia vera in 1, and plasma cell myeloma in 2. Clinical follow-up was available in 12 patients, mean of 29 months (range 4-120 months). In 10 patients for whom treatment history could be obtained, 9 were treated with chemotherapy, and 1 was treated with steroids. The mean creatinine at last follow-up was 2 mg/dl (range 1.2-3.9 mg/dl) (n=9). Ten patients died in the follow-up period from their underlying hematological disease and had persistent renal disease. The two remaining patients had persistent chronic kidney disease. Renal extramedullary hematopoiesis should be considered in the differential diagnosis of interstitial infiltrates, particularly in the presence of a glomerulopathy and a hematologic malignancy.

  16. Compartmental architecture and dynamics of hematopoiesis.

    Directory of Open Access Journals (Sweden)

    David Dingli

    Full Text Available BACKGROUND: Blood cell formation is maintained by the replication of hematopoietic stem cells (HSC that continuously feed downstream "compartments" where amplification and differentiation of cells occurs, giving rise to all blood lineages. Whereas HSC replicate slowly, committed cells replicate faster as they become more differentiated. METHODOLOGY/SIGNIFICANT FINDING: We propose a multi-compartment model of hematopoiesis, designed on the principle of cell flow conservation under stationary conditions. Cells lost from one compartment due to differentiation are replaced by cells from the upstream compartment. We assume that there is a constant relationship between cell input and output in each compartment and fix the single parameter of the model using data available for granulocyte maturation. We predict that approximately 31 mitotic events separate the HSC from the mature cells observed in the circulation. Besides estimating the number of compartments, our model allows us to estimate the size of each compartment, the rate of cell replication within each compartment, the mean time a given cell type contributes to hematopoiesis, the amplification rate in each compartment, as well as the mean time separating stem-cell replication and mature blood-cell formation. CONCLUSIONS: Despite its simplicity, the model agrees with the limited in vivo data available and can make testable predictions. In particular, our prediction of the average lifetime of a PIG-A mutated clone agrees closely with the experimental results available for the PIG-A gene mutation in healthy adults. The present elucidation of the compartment structure and dynamics of hematopoiesis may prove insightful in further understanding a variety of hematopoietic disorders.

  17. Intracranial Extramedullary Hematopoiesis in Beta-Thalassemia

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    Karki, Bivek; Xu, Yi Kai; Wu, Yuan Kui [Nan fang Hospital, Southern Medical University, Guangzhou (China); Tamrakar, Karuna [Zhujiang Hospital, Southern Medical University, Guangzhou (China)

    2012-03-15

    Extramedullary hematopoiesis (EMH) represents tumor-like proliferation of hemopoietic tissue which complicates chronic hemoglobinopathy. Intracranial EMH is an extremely rare occurrence. Magnetic resonance imaging (MRI) offers a precise diagnosis. It is essential to distinguish EMH from other extradural central nervous system tumors, because treatment and prognosis are totally different. Herein, we report the imaging findings of beta-thalassemia in a 13-year-old boy complaining of weakness of left side of the body and gait disturbance; CT and MRI revealed an extradural mass in the right temporoparietal region.

  18. Intracranial Extramedullary Hematopoiesis in Beta-Thalassemia

    International Nuclear Information System (INIS)

    Karki, Bivek; Xu, Yi Kai; Wu, Yuan Kui; Tamrakar, Karuna

    2012-01-01

    Extramedullary hematopoiesis (EMH) represents tumor-like proliferation of hemopoietic tissue which complicates chronic hemoglobinopathy. Intracranial EMH is an extremely rare occurrence. Magnetic resonance imaging (MRI) offers a precise diagnosis. It is essential to distinguish EMH from other extradural central nervous system tumors, because treatment and prognosis are totally different. Herein, we report the imaging findings of beta-thalassemia in a 13-year-old boy complaining of weakness of left side of the body and gait disturbance; CT and MRI revealed an extradural mass in the right temporoparietal region.

  19. Extramedullary paraspinal hematopoiesis in hereditary spherocytosis

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    Gogia P

    2008-01-01

    Full Text Available Hereditary spherocytosis (HS is a common inherited hemolytic anemia due to red cell membrane defects. Extramedullary hematopoiesis is a compensatory response to insufficient bone marrow blood cell production. The preferred sites of extramedullary hematopoietic involvement are the spleen, liver and lymph nodes; but in HS, the posterior paravertebral mediastinum is also commonly involved. We report a case of a 50-year-old male who presented to us in respiratory distress and with bilateral paravertebral posterior mediastinal masses, which on trucut biopsy were found to be extra-hematopoietic masses; and the patient was found to have hereditary spherocytosis.

  20. Intracranial extramedullary hematopoiesis in beta-thalassemia.

    Science.gov (United States)

    Karki, Bivek; Xu, Yi-Kai; Tamrakar, Karuna; Wu, Yuan-Kui

    2012-01-01

    Extramedullary hematopoiesis (EMH) represents tumor-like proliferation of hemopoietic tissue which complicates chronic hemoglobinopathy. Intracranial EMH is an extremely rare occurrence. Magnetic resonance imaging (MRI) offers a precise diagnosis. It is essential to distinguish EMH from other extradural central nervous system tumors, because treatment and prognosis are totally different. Herein, we report the imaging findings of beta-thalassemia in a 13-year-old boy complaining of weakness of left side of the body and gait disturbance; CT and MRI revealed an extradural mass in the right temporoparietal region.

  1. Surgical treatment of an unusual case of pelvic extramedullary hematopoiesis.

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    Khen-Dunlop, Naziha; Girot, Robert; Brunelle, Francis; Révillon, Yann; Nihoul-Fékété, Claire; Sarnacki, Sabine

    2006-07-01

    Extramedullary hematopoiesis affects about 15% of the patients treated for thalassemia intermedia. Usually seen in adulthood, the most common location is the paraspinal region. Diagnosis and treatment of extramedullary hematopoiesis located in the pelvis of a young 15-year-old girl is discussed. The young age of the patient and the uncommon site of the mass first lead to the diagnosis of an ovarian dermoid cyst. Because of the clinical history and the typical feature on computed tomography scan, extramedullary hematopoiesis was concluded. A specific treatment based on blood transfusion and hydroxyurea was first proposed but remained inefficient. Surgical excision was thus successfully performed. Whereas surgery is limited to spinal cord compression in paraspinal extramedullary hematopoiesis, this observation argues for surgical treatment in symptomatic intraabdominal extramedullary hematopoiesis when medical treatment fails.

  2. Thalassemia, extramedullary hematopoiesis, and spinal cord compression: A case report

    OpenAIRE

    Bukhari, Syed Sarmad; Junaid, Muhammad; Rashid, Mamoon Ur

    2016-01-01

    Background: Extramedullary hematopoiesis (EMH) refers to hematopoiesis outside of the medulla of the bone. Chronic anemia states such as thalassemia can cause hematopoietic tissue to expand in certain locations. We report a case of spinal cord compression due to recurrent spinal epidural EMH, which was treated with a combination of surgery and radiotherapy. Pakistan has one of the highest incidence and prevalence of thalassemia in the world. We describe published literature on diagnosis and m...

  3. Extramedullary paraspinal hematopoiesis in thalassemia: CT and MRI evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Tsitouridis, J.; Stamos, S.; Hassapopoulou, E.; Tsitouridis, K.; Nikolopoulos, P

    1999-04-01

    We present a comparative CT and MRI study of the paraspinal extramedullary hematopoiesis in 32 thalassemic patients. The patients were classified into four groups according to the MRI and CT imaging findings. Active recent extramedullary paraspinal hematopoietic masses show soft tissue behavior in both CT and MRI. Older inactive masses reveal iron deposition or fatty replacement. Combined imaging findings of paraspinal extramedullary hematopoiesis revealed the phase of its evolution and the correct diagnosis.

  4. Hematopoiesis and Hematopoietic Organs in Arthropods

    Science.gov (United States)

    Grigorian, Melina; Hartenstein, Volker

    2013-01-01

    Hemocytes (blood cells) are motile cells moving throughout the extracellular space and exist in all clades of the animal kingdom. Hemocytes play an important role in shaping the extracellular environment and in the immune response. Developmentally, hemocytes are closely related to the epithelial cells lining the vascular system (endothelia) and body cavity (mesothelia). In vertebrates and insects, common progenitors, called hemangioblasts, give rise to the endothelia and blood cells. In the adult animal, many differentiated hemocytes seem to retain the ability to proliferate; however, in most cases investigated closely, the bulk of hemocyte proliferation takes place in specialized hematopoietic organs. Hematopoietic organs provide an environment where undifferentiated blood stem cells are able to self renew, and at the same time generate offspring that differentiate into different blood cell types. Hematopoiesis in vertebrates, taking place in the bone marrow, has been subject to intensive research by immunologists and stem cell biologists. Much less is known about blood cell formation in invertebrate animals. In this review we will survey structural and functional properties of invertebrate hematopoietic organs, with a main focus on insects and other arthropod taxa. We will then discuss similarities, at the molecular and structural level, that are apparent when comparing the development of blood cells in hematopoietic organs of vertebrates and arthropods. Our comparative review is intended to elucidate aspects of the biology of blood stem cells that are more easily missed when focusing on one or a few model species. PMID:23319182

  5. Hematopoiesis and hematopoietic organs in arthropods.

    Science.gov (United States)

    Grigorian, Melina; Hartenstein, Volker

    2013-03-01

    Hemocytes (blood cells) are motile cells that move throughout the extracellular space and that exist in all clades of the animal kingdom. Hemocytes play an important role in shaping the extracellular environment and in the immune response. Developmentally, hemocytes are closely related to the epithelial cells lining the vascular system (endothelia) and the body cavity (mesothelia). In vertebrates and insects, common progenitors, called hemangioblasts, give rise to the endothelia and blood cells. In the adult animal, many differentiated hemocytes seem to retain the ability to proliferate; however, in most cases investigated closely, the bulk of hemocyte proliferation takes place in specialized hematopoietic organs. Hematopoietic organs provide an environment where undifferentiated blood stem cells are able to self-renew, and at the same time generate offspring that differentiate into different blood cell types. Hematopoiesis in vertebrates, taking place in the bone marrow, has been subject to intensive research by immunologists and stem cell biologists. Much less is known about blood cell formation in invertebrate animals. In this review, we will survey structural and functional properties of invertebrate hematopoietic organs, with a main focus on insects and other arthropod taxa. We will then discuss similarities, at the molecular and structural level, that are apparent when comparing the development of blood cells in hematopoietic organs of vertebrates and arthropods. Our comparative review is intended to elucidate aspects of the biology of blood stem cells that are more easily missed when focusing on one or a few model species.

  6. Recognition of strong seasonality and climatic cyclicity in an ancient, fluvially dominated, tidally influenced point bar: Middle McMurray Formation, Lower Steepbank River, north-eastern Alberta, Canada

    Science.gov (United States)

    Jablonski, Bryce V. J.; Dalrymple, Robert W.

    2016-04-01

    Inclined heterolithic stratification in the Lower Cretaceous McMurray Formation, exposed along the Steepbank River in north-eastern Alberta, Canada, accumulated on point bars of a 30 to 40 m deep continental-scale river in the fluvial-marine transition. This inclined heterolithic stratification consists of two alternating lithologies, sand and fine-grained beds. Sand beds were deposited rapidly by unidirectional currents and contain little or no bioturbation. Fine-grained beds contain rare tidal structures, and are intensely bioturbated by low-diversity ichnofossil assemblages. The alternations between the sand and fine-grained beds are probably caused by strong variations in fluvial discharge; that are believed to be seasonal (probably annual) in duration. The sand beds accumulated during river floods, under fluvially dominated conditions when the water was fresh, whereas the fine-grained beds accumulated during the late stages of the river flood and deposition continued under tidally influenced brackish-water conditions during times of low-river flow (i.e. the interflood periods). These changes reflect the annual migration in the positions of the tidal and salinity limits within the fluvial-marine transition that result from changes in river discharge. Sand and fine-grained beds are cyclically organized in the studied outcrops forming metre-scale cycles. A single metre-scale cycle is defined by a sharp base, an upward decrease in sand-bed thickness and upward increases in the preservation of fine-grained beds and the intensity of bioturbation. Metre-scale cycles are interpreted to be the product of a longer term (decadal) cyclicity in fluvial discharge, probably caused by fluctuations in ocean or solar dynamics. The volumetric dominance of river-flood deposits within the succession suggests that accumulation occurred in a relatively landward position within the fluvial-marine transition. This study shows that careful observation can reveal much about the

  7. [A case of cutaneous extramedullary hematopoiesis associated with idiopathic myelofibrosis].

    Science.gov (United States)

    Corella, F; Barnadas, M A; Bordes, R; Curell, R; Espinosa, I; Vergara, C; Alomar, A

    2008-05-01

    Cutaneous extramedullary hematopoiesis is a rare manifestation of chronic myeloproliferative processes, mainly chronic idiopathic myelofibrosis. In adults, it manifests as macules, papules, nodules, and ulcers on the trunk. The lesions usually appear soon after diagnosis and the possibility of a relationship between splenectomy and the appearance of extramedullary foci of hematopoiesis is still debated. Diagnosis is based on histopathology showing an infiltrate with different combinations of myeloid and erythroid cell precursors and megakaryocytes. Symptomatic treatment is provided alongside treatment of the underlying disease. We report a new case associated with chronic idiopathic myelofibrosis in which foci of cutaneous extramedullary hematopoiesis were observed 9 years after initial diagnosis. The lesions were progressive and the patient went on to develop acute myeloid leukemia.

  8. Piwi genes are dispensable for normal hematopoiesis in mice.

    Directory of Open Access Journals (Sweden)

    Mona J Nolde

    Full Text Available Hematopoietic stem cells (HSC must engage in a life-long balance between self-renewal and differentiation to sustain hematopoiesis. The highly conserved PIWI protein family regulates proliferative states of stem cells and their progeny in diverse organisms. A Human piwi gene (for clarity, the non-italicized "piwi" refers to the gene subfamily, HIWI (PIWIL1, is expressed in CD34⁺ stem/progenitor cells and transient expression of HIWI in a human leukemia cell line drastically reduces cell proliferation, implying the potential function of these proteins in hematopoiesis. Here, we report that one of the three piwi genes in mice, Miwi2 (Piwil4, is expressed in primitive hematopoetic cell types within the bone marrow. Mice with a global deletion of all three piwi genes, Miwi, Mili, and Miwi2, are able to maintain long-term hematopoiesis with no observable effect on the homeostatic HSC compartment in adult mice. The PIWI-deficient hematopoetic cells are capable of normal lineage reconstitution after competitive transplantation. We further show that the three piwi genes are dispensable during hematopoietic recovery after myeloablative stress by 5-FU. Collectively, our data suggest that the function of the piwi gene subfamily is not required for normal adult hematopoiesis.

  9. Intracranial extramedullary hematopoiesis: a rare cause of headaches.

    Science.gov (United States)

    Singer, Adam; Quencer, Robert

    2014-01-01

    Ectopic bone marrow production, known as extramedullary hematopoiesis, may result in symptoms due to compression on normal structures. We present the multimodality imaging findings and subsequent management of a rare case of symptomatic extramedullary hematopoiesis within the calvarium. Case report. A 54-year-old male with a history of myelofibrosis and no previous diagnosis of a headache disorder presented to the emergency department with worsening severe bilateral headaches. A nonenhanced CT of the brain was performed and diffuse extra-axial nodular hyperdensities were visualized. MRI of the brain demonstrated diffuse extra-axial avidly enhancing nodular masses, dural thickening and marked susceptibility. No paravertebral masses, typical for extramedullary hematopoiesis, were present in the chest or abdomen. Although the clinical team considered a biopsy to confirm the diagnosis, we suggested a noninvasive confirmatory test. The subsequent Tc99m sulfur colloid scan corroborated the diagnosis. The patient was then referred to radiation oncology for treatment. In summary, extramedullary hematopoiesis is a hematologic compensatory disorder that rarely occurs within the CNS and may cause neurological compromise due to compression on underlying structures. The diagnosis can be made with noninvasive imaging and treated with low dose radiation therapy. Copyright © 2013 by the American Society of Neuroimaging.

  10. Cyclic Vitalism

    DEFF Research Database (Denmark)

    Halse, Sven

    2014-01-01

    an enthusiastic worshipping of life, one that holds youth, health, strength and beauty as its primary attributes, and which was prevalent in all aspects of cultural life around 1900. But even the post war founders of the Vitalist re-conceptualisation of this era, Wolfdietrich Rasch and Gunter Martens, warned...... that also encompasses notions of destruction, decay and death. “All life symbols in literature around 1900 are at the same time symbols of death”. (Rasch, W. 1967:24) Through the analyses of three poems, this article aims to show concrete examples of how cyclic Vitalist thinking is embedded in poetry...

  11. Cyclic multiverses

    Science.gov (United States)

    Marosek, Konrad; Dąbrowski, Mariusz P.; Balcerzak, Adam

    2016-09-01

    Using the idea of regularization of singularities due to the variability of the fundamental constants in cosmology we study the cyclic universe models. We find two models of oscillating and non-singular mass density and pressure (`non-singular' bounce) regularized by varying gravitational constant G despite the scale factor evolution is oscillating and having sharp turning points (`singular' bounce). Both violating (big-bang) and non-violating (phantom) null energy condition models appear. Then, we extend this idea on to the multiverse containing cyclic individual universes with either growing or decreasing entropy though leaving the net entropy constant. In order to get an insight into the key idea, we consider the doubleverse with the same geometrical evolution of the two `parallel' universes with their physical evolution [physical coupling constants c(t) and G(t)] being different. An interesting point is that there is a possibility to exchange the universes at the point of maximum expansion - the fact which was already noticed in quantum cosmology. Similar scenario is also possible within the framework of Brans-Dicke theory where varying G(t) is replaced by the dynamical Brans-Dicke field φ(t) though these theories are slightly different.

  12. Extramedullary hematopoiesis: a rare occurrence in the sinonasal tract.

    Science.gov (United States)

    Bizzoni, Andrea; Lombardi, Davide; Maroldi, Roberto; Incardona, Paolo; Nicolai, Piero

    2010-04-01

    Extramedullary hematopoiesis (EMH) is a systemic reaction to inadequate hematopoiesis. We report two exceedingly rare cases of EMH involving the paranasal sinuses. The first patient, a 30-year-old man, presented with a maxillary sinus mass. The lesion was excised by endoscopic surgery: definitive histology identified foci of EMH within an inflammatory fibromyxoid pseudotumor. The second case occurred in a 29-year-old man affected by intermediate beta-thalassemia. He was hospitalized with a diagnosis of sphenoid sinus mucocele secondary to an ethmoid lesion. The patient underwent endoscopic excision of the mass and drainage of the sphenoid mucocele. At definitive histology, a diagnosis of EMH was established. Herein, the presenting modalities, imaging profile, and treatment options of this rare EMH localization are reviewed. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

  13. Ex vivo tools for the clonal analysis of zebrafish hematopoiesis

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Ondřej; Stachura, D.L.; Machoňová, Olga; Zon, L.I.; Traver, D.; Bartůněk, Petr

    2016-01-01

    Roč. 11, č. 5 (2016), s. 1007-1020 ISSN 1754-2189 R&D Projects: GA MŠk LO1419; GA ČR GA16-21024S Institutional support: RVO:68378050 Keywords : stem-cells * in-vitro * vertebrate hematopoiesis * transgenic zebrafish * progenitor cells * danio - rerio * fish * thrombopoietin * identification * specification Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 10.032, year: 2016

  14. Suppression of hepatic hematopoiesis with radioactive gold (198Au)

    International Nuclear Information System (INIS)

    Turner, A.R.; Gummerman, L.W.; Boggs, D.R.

    1985-01-01

    A patient with idiopathic myelofibrosis of some 20 yr duration developed esophageal varices and ascites. No explanation for increased portal pressure other than hepatic hematopoiesis was found. Consequently, a trial of cobalt irradiation to the liver was undertaken with definite but transient decrease in ascites. Subsequently, two courses of radioactive colloidal gold were given, again with definite but transient beneficial effects on the degree of ascites. This latter benefit occurred without suppression of marrow function

  15. Influence on radiogenic alterations in hematopoiesis - Situation and possibilities

    International Nuclear Information System (INIS)

    Kehrberg, G.; Rose, H.; Saul, G.; Riessbeck, K.H.

    1985-01-01

    Radiogenic alterations of hematopoiesis are a main topic in radiobiological investigations. By further elucidation of the regulatory mechanisms possibly follow new starting points to accelerate the regeneration of stem cells, still capable of proliferating, or differentiation of most endangered and nearly irretrievable cell populations by drugs. The present state is discussed concerning the application of anabolics, endotoxins, thymic extracts, cyanoethylurea, and lithium carbonate as well as parenteral nutrition and competition of stem cells. (author)

  16. Premature epiphyseal fusion and extramedullary hematopoiesis in thalassemia

    International Nuclear Information System (INIS)

    Colavita, N.; Orazi, C.; Danza, S.M.; Falappa, P.G.; Fabbri, R.

    1987-01-01

    The main skeletal abnormalities in β-thalassemia are widening of medullary spaces, rarefaction of bone trabeculae, thinning of cortical bone, and perpendicular periosteal spiculation. Premature epiphyseal fusion (PEF) and extramedullary hematopoiesis (EH) are found, though more rarely. The incidence of PEF and EH in 64 patients affected by β-thalassemia is reported. The different incidence of such complications in thalassemia major and intermedia is reported, and a possible correlation with transfusion regimen is also considered. (orig.)

  17. Novel Insights into the Genetic Controls of Primitive and Definitive Hematopoiesis from Zebrafish Models

    Directory of Open Access Journals (Sweden)

    Raman Sood

    2012-01-01

    Full Text Available Hematopoiesis is a dynamic process where initiation and maintenance of hematopoietic stem cells, as well as their differentiation into erythroid, myeloid and lymphoid lineages, are tightly regulated by a network of transcription factors. Understanding the genetic controls of hematopoiesis is crucial as perturbations in hematopoiesis lead to diseases such as anemia, thrombocytopenia, or cancers, including leukemias and lymphomas. Animal models, particularly conventional and conditional knockout mice, have played major roles in our understanding of the genetic controls of hematopoiesis. However, knockout mice for most of the hematopoietic transcription factors are embryonic lethal, thus precluding the analysis of their roles during the transition from embryonic to adult hematopoiesis. Zebrafish are an ideal model organism to determine the function of a gene during embryonic-to-adult transition of hematopoiesis since bloodless zebrafish embryos can develop normally into early larval stage by obtaining oxygen through diffusion. In this review, we discuss the current status of the ontogeny and regulation of hematopoiesis in zebrafish. By providing specific examples of zebrafish morphants and mutants, we have highlighted the contributions of the zebrafish model to our overall understanding of the roles of transcription factors in regulation of primitive and definitive hematopoiesis.

  18. Ekpyrotic and cyclic cosmology

    International Nuclear Information System (INIS)

    Lehners, Jean-Luc

    2008-01-01

    Ekpyrotic and cyclic cosmologies provide theories of the very early and of the very late universe. In these models, the big bang is described as a collision of branes - and thus the big bang is not the beginning of time. Before the big bang, there is an ekpyrotic phase with equation of state w=P/(ρ) >>1 (where P is the average pressure and ρ the average energy density) during which the universe slowly contracts. This phase resolves the standard cosmological puzzles and generates a nearly scale-invariant spectrum of cosmological perturbations containing a significant non-Gaussian component. At the same time it produces small-amplitude gravitational waves with a blue spectrum. The dark energy dominating the present-day cosmological evolution is reinterpreted as a small attractive force between our brane and a parallel one. This force eventually induces a new ekpyrotic phase and a new brane collision, leading to the idea of a cyclic universe. This review discusses the detailed properties of these models, their embedding in M-theory and their viability, with an emphasis on open issues and observational signatures

  19. Effects of deuteration on hematopoiesis in the mouse

    International Nuclear Information System (INIS)

    Adams, W.H.; Adams, D.G.

    1988-01-01

    Mice ingesting 30 to 50% D 2 O (heavy water, deuterium oxide) developed a dose-dependent depression of formed peripheral blood elements in 4 to 9 days. The principal mechanism of anemia and thrombocytopenia is impaired hematopoiesis. Despite pancytopenia in the peripheral blood, bone marrow cellularity and morphology remained normal. Upon replacement of D 2 O with tap water, platelet and neutrophil concentrations returned to normal within 48 to 72 hr. In contrast, blood lymphocyte concentrations remained low for several weeks. B-lymphocytes may be more affected by deuteration than other lymphocyte subsets. In vivo reticuloendothelial cell function, as assessed by 51 Cr-labeled sheep erythrocyte clearance, was unaffected by D 2 O. Although a dose-dependent decrease in fluid intake occurred during deuteration, hematocytopenia was not a consequence of dehydration. In view of the known kinetics of D 2 O in biological systems, the rapid response of myeloid elements to deuteration must be due primarily to the solvent (nonmetabolic) isotope effect. Prolonged deuteration has proven toxic when included in regimens for treatment of neoplasia, including leukemia, in animal models. The present study shows that modulation of hematopoiesis by D 2 O is possible without invoking the toxicities associated with prolonged deuteration

  20. Thalassemia, extramedullary hematopoiesis, and spinal cord compression: A case report.

    Science.gov (United States)

    Bukhari, Syed Sarmad; Junaid, Muhammad; Rashid, Mamoon Ur

    2016-01-01

    Extramedullary hematopoiesis (EMH) refers to hematopoiesis outside of the medulla of the bone. Chronic anemia states such as thalassemia can cause hematopoietic tissue to expand in certain locations. We report a case of spinal cord compression due to recurrent spinal epidural EMH, which was treated with a combination of surgery and radiotherapy. Pakistan has one of the highest incidence and prevalence of thalassemia in the world. We describe published literature on diagnosis and management of such cases. An 18-year-old male presented with bilateral lower limb paresis. He was a known case of homozygous beta thalassemia major. He had undergone surgery for spinal cord compression due to EMH 4 months prior to presentation. Symptom resolution was followed by deterioration 5 days later. He was operated again at our hospital with complete resection of the mass. He underwent local radiotherapy to prevent recurrence. At 2 years follow-up, he showed complete resolution of symptoms. Follow-up imaging demonstrated no residual mass. The possibility of EMH should be considered in every patient with ineffective erythropoiesis as a cause of spinal cord compression. Treatment of such cases is usually done with blood transfusions, which can reduce the hematopoietic drive for EMH. Other options include surgery, hydroxyurea, radiotherapy, or a combination of these on a case to case basis.

  1. miRNAs in Normal and Malignant Hematopoiesis

    Directory of Open Access Journals (Sweden)

    Ryutaro Kotaki

    2017-07-01

    Full Text Available Lineage specification is primarily regulated at the transcriptional level and lineage-specific transcription factors determine cell fates. MicroRNAs (miRNAs are 18–24 nucleotide-long non-coding RNAs that post-transcriptionally decrease the translation of target mRNAs and are essential for many cellular functions. miRNAs also regulate lineage specification during hematopoiesis. This review highlights the roles of miRNAs in B-cell development and malignancies, and discusses how miRNA expression profiles correlate with disease prognoses and phenotypes. We also discuss the potential for miRNAs as therapeutic targets and diagnostic tools for B-cell malignancies.

  2. Adrenal extramedullary hematopoiesis associated with β-thalassemia major.

    Science.gov (United States)

    Keikhaei, Bijan; Shirazi, Ahmad Soltani; Pour, Mahboob Mohammad

    2012-05-10

    The presence of apparently normal hematopoietic tissue outside of bone marrow cavity is defined as extramedullary hematopoiesis (EMH). EMH is a rare complication in thalassemia major (TM) and adrenal gland as well. This report describes a case of adrenal EMH in a 26-year-old man with β-TM. He has been transfused with regular blood transfusion since 9 months. During the routine physical examination he was incidentally found to have a hypoechoic mass at his abdominal ultrasonography. Abdominal computed tomography scan revealed a right well-defined suprarenal mass 7.7×7.3×5.8 cm in size. The diagnosis of EMH was confirmed with ultrasonographic-guided fine needle biopsy. Treatment options which include intensified regular blood transfusion and hydroxyurea have been started.

  3. Endoglin potentiates nitric oxide synthesis to enhance definitive hematopoiesis

    Science.gov (United States)

    Nasrallah, Rabab; Knezevic, Kathy; Thai, Thuan; Thomas, Shane R.; Göttgens, Berthold; Lacaud, Georges; Kouskoff, Valerie; Pimanda, John E.

    2015-01-01

    ABSTRACT During embryonic development, hematopoietic cells develop by a process of endothelial-to hematopoietic transition of a specialized population of endothelial cells. These hemogenic endothelium (HE) cells in turn develop from a primitive population of FLK1+ mesodermal cells. Endoglin (ENG) is an accessory TGF-β receptor that is enriched on the surface of endothelial and hematopoietic stem cells and is also required for the normal development of hemogenic precursors. However, the functional role of ENG during the transition of FLK1+ mesoderm to hematopoietic cells is ill defined. To address this we used a murine embryonic stem cell model that has been shown to mirror the temporal emergence of these cells in the embryo. We noted that FLK1+ mesodermal cells expressing ENG generated fewer blast colony-forming cells but had increased hemogenic potential when compared with ENG non-expressing cells. TIE2+/CD117+ HE cells expressing ENG also showed increased hemogenic potential compared with non-expressing cells. To evaluate whether high ENG expression accelerates hematopoiesis, we generated an inducible ENG expressing ES cell line and forced expression in FLK1+ mesodermal or TIE2+/CD117+ HE cells. High ENG expression at both stages accelerated the emergence of CD45+ definitive hematopoietic cells. High ENG expression was associated with increased pSMAD2/eNOS expression and NO synthesis in hemogenic precursors. Inhibition of eNOS blunted the ENG induced increase in definitive hematopoiesis. Taken together, these data show that ENG potentiates the emergence of definitive hematopoietic cells by modulating TGF-β/pSMAD2 signalling and increasing eNOS/NO synthesis. PMID:25979706

  4. Endoglin potentiates nitric oxide synthesis to enhance definitive hematopoiesis

    Directory of Open Access Journals (Sweden)

    Rabab Nasrallah

    2015-07-01

    Full Text Available During embryonic development, hematopoietic cells develop by a process of endothelial-to hematopoietic transition of a specialized population of endothelial cells. These hemogenic endothelium (HE cells in turn develop from a primitive population of FLK1+ mesodermal cells. Endoglin (ENG is an accessory TGF-β receptor that is enriched on the surface of endothelial and hematopoietic stem cells and is also required for the normal development of hemogenic precursors. However, the functional role of ENG during the transition of FLK1+ mesoderm to hematopoietic cells is ill defined. To address this we used a murine embryonic stem cell model that has been shown to mirror the temporal emergence of these cells in the embryo. We noted that FLK1+ mesodermal cells expressing ENG generated fewer blast colony-forming cells but had increased hemogenic potential when compared with ENG non-expressing cells. TIE2+/CD117+ HE cells expressing ENG also showed increased hemogenic potential compared with non-expressing cells. To evaluate whether high ENG expression accelerates hematopoiesis, we generated an inducible ENG expressing ES cell line and forced expression in FLK1+ mesodermal or TIE2+/CD117+ HE cells. High ENG expression at both stages accelerated the emergence of CD45+ definitive hematopoietic cells. High ENG expression was associated with increased pSMAD2/eNOS expression and NO synthesis in hemogenic precursors. Inhibition of eNOS blunted the ENG induced increase in definitive hematopoiesis. Taken together, these data show that ENG potentiates the emergence of definitive hematopoietic cells by modulating TGF-β/pSMAD2 signalling and increasing eNOS/NO synthesis.

  5. Cyclic Railway Timetable Optimization

    NARCIS (Netherlands)

    L.W.P. Peeters (Leon)

    2003-01-01

    textabstractCyclic Railway Timetable Optimization describes mathematical models and solution methods for constructing high quality cyclic railway timetables. In a cyclic timetable, a train for a certain destination leaves a certain station at the same time every cycle time, say every half an hour,

  6. Expression of Pitx2 in stromal cells is required for normal hematopoiesis

    OpenAIRE

    Kieusseian, Aurélie; Chagraoui, Jalila; Kerdudo, Cécile; Mangeot, Philippe-Emmanuel; Gage, Philip J.; Navarro, Nicole; Izac, Brigitte; Uzan, Georges; Forget, Bernard G.; Dubart-Kupperschmitt, Anne

    2006-01-01

    Although the expression of Pitx2, a bicoid family homeodomain transcription factor, is highly regulated during hematopoiesis, its function during this process was not documented; we thus studied hematopoiesis in Pitx2-null mice. We found that Pitx2–/– embryos display hypoplastic livers with reduced numbers of hematopoietic cells, but these cells had normal hematopoietic potential, as evidenced by colony-forming assays, immature progenitor cell assays, and long-term repopulation assays. Becaus...

  7. Pulmonary Extramedullary Hematopoiesis in a Patient with Chronic Asthma Resembling Lung Cancer: A Case Report

    Directory of Open Access Journals (Sweden)

    Massood Hosseinzadeh

    2012-01-01

    Full Text Available Background. Extramedullary hematopoiesis is most often seen in reticuloendothelial organs specially spleen, liver, or lymph nodes, and it is rarely seen in lung parenchyma. Almost all reported cases of pulmonary extramedullary hematopoiesis occurred following myeloproliferative disorders specially myelofibrosis. Other less common underlying causes are thalassemia syndromes and other hemoglobinopathies. There was not any reported case of pulmonary extramedullary hematopoiesis in asthmatic patients in the medical literature. Case. Here we reported a 65-year-old lady who was a known case of bronchial asthma with recent developed right lower lobe lung mass. Chest X-ray and CT studies showed an infiltrating mass resembling malignancy. Fine needle aspiration cytology of mass revealed pulmonary extramedullary hematopoiesis. The patient followed for 10 months with serial physical examination and laboratory evaluations which were unremarkable. Conclusion. Extramedullary hematopoiesis of lung parenchyma can be mistaken for lung cancer radiologically. Although previous reported cases occurred with myelofibrosis or hemoglobinopathies, we are reporting the first case of asthma-associated extramedullary hematopoiesis.

  8. Intracranial extramedullary hematopoiesis masquerading as progressive metastasis in a child with stage 4 neuroblastoma: Utility of sulfur colloid scan

    Directory of Open Access Journals (Sweden)

    Sajid S. Qureshi

    2016-10-01

    Full Text Available Extramedullary hematopoiesis is production of blood cells outside bone marrow which occurs in a variety of disorders including myelofibrosis. We present a 15 month old child with stage 4 neuroblastoma with secondary myelofibrosis which resulted in intracranial extramedullary hematopoiesis, posing a diagnostic and therapeutic dilemma. This was resolved with a sulfur colloid isotope scan which confirmed extramedullary hematopoiesis and not a progressing metastasis. This helped us continue therapy with curative intent. To the best of our knowledge we did not come across any report of neuroblastoma with myelofibrosis and intracranial extramedullary hematopoiesis mimicking progression of metastasis.

  9. Hematopoietic lineage distribution and evolutionary dynamics of clonal hematopoiesis.

    Science.gov (United States)

    Arends, Christopher Maximilian; Galan-Sousa, Joel; Hoyer, Kaja; Chan, Willy; Jäger, Marten; Yoshida, Kenichi; Seemann, Ricarda; Noerenberg, Daniel; Waldhueter, Nils; Fleischer-Notter, Helga; Christen, Friederike; Schmitt, Clemens A; Dörken, Bernd; Pelzer, Uwe; Sinn, Marianne; Zemojtel, Tomasz; Ogawa, Seishi; Märdian, Sven; Schreiber, Adrian; Kunitz, Annegret; Krüger, Ulrike; Bullinger, Lars; Mylonas, Elena; Frick, Mareike; Damm, Frederik

    2018-03-01

    Clonal hematopoiesis of indeterminate potential (CHIP) occurs in an age-related manner and associates with an increased risk of hematologic cancer, atherosclerotic disease, and shorter overall survival. Little is known about the cell of origin, repartition patterns of clonal mutations within the hematopoietic differentiation tree, and its dynamics under evolutionary pressure. Using targeted sequencing, CHIP was identified in 121 out of 437 elderly individuals (27.7%). Variant allele frequencies (VAFs) of 91 mutations were studied in six peripheral blood cell fractions. VAFs were significantly higher in monocytes, granulocytes, and NK-cells compared to B- or T cells. In all cases with available bone marrow material, mutations could be identified in Lin - CD34 + CD38 - HSCs with subsequent expansion to myeloid primed progenitors. In 22 patients with solid cancer receiving (radio-)chemotherapy, longitudinal study of 32 mutations at 121 time points identified relative VAF changes of at least 50% in 13/32 mutations. VAFs of DNMT3A, were stable in 12/13 cases (P < .001). Cancer patients with a clonal mutation other than DNMT3A required more often red blood cell transfusions and dose reductions. Our results provide novel insights into cellular distribution of clonal mutations, their dynamics under chemotherapy, and advocate for systematic analyses for CHIP in cancer patients.

  10. Spinal cord compression secondary to extramedullary hematopoiesis in a dog.

    Science.gov (United States)

    Williams, Lindsay M; Skeen, Todd M

    2013-03-15

    An 11-year-old spayed female Siberian Husky was evaluated because of a 2-week history of progressive paraparesis. Results of neurologic examination were consistent with a T3-L3 myelopathy. There were no abnormalities on CBC, and hypercalcemia was noted on serum biochemical analysis. Several hypoechoic splenic nodules were evident on abdominal ultrasonography, and results of fine-needle aspiration cytology were consistent with splenic extramedullary hematopoiesis (EMH). Two compressive, extradural masses in the dorsal epidural space of the thoracolumbar region of the spinal cord were seen on MRI images. A dorsal laminectomy was performed to remove the extradural spinal masses. Results of histologic examination of tissue samples were consistent with EMH. Following surgery, clinical signs of paraparesis resolved, and there was no recurrence of the masses 24 months after surgery. Extramedullary hematopoesis should be considered as a differential diagnosis in dogs in which results of diagnostic imaging indicate a epidural mass. In human patients, spinal EMH usually occurs secondary to an underlying hematologic disease, but it can also occur spontaneously. Treatment options reported for humans include surgical decompression, radiation therapy, chemotherapy, and blood transfusion. The dog of this report responded favorably to surgical decompression and was clinically normal 2 years after surgery.

  11. Extramedullary Hematopoiesis in Uterine Leiomyoma Associated with Numerous Intravascular Thrombi

    Directory of Open Access Journals (Sweden)

    Xiaoyan Cui

    2014-01-01

    Full Text Available We report a case of extramedullary hematopoiesis (EMH in uterine leiomyoma and associated numerous intravascular thrombi. A 29-year-old nulliparous female presented with heavy vaginal bleeding and a hematocrit of 22%. No bone marrow biopsy has been performed. She had a history of uterine leiomyomata and menorrhagia for a year. A transvaginal ultrasound confirmed the presence of a uterine leiomyoma. The patient was treated conservatively with oral contraceptive pills due to desire for fertility. However, she continued to have heavy vaginal bleeding and developed bilateral upper extremity deep vein thrombosis and multiple superficial vein thromboses after two months. An exploratory laparotomy with uterine myomectomy was performed. Gross examination of the specimen revealed a single nodular mass measuring 10.0×9.5×7.5 cm with a white-tan swirling cut surface. Microscopic examination revealed benign smooth muscle consistent with leiomyoma and numerous intravascular thrombi both with areas of EMH. Immunohistochemical stains confirmed the presence of all three benign lineages of hematopoietic cells. Occurrence of EMH in uterine leiomyoma and intravascular thrombi is very rare. It may be related to systemic hematopoietic stimulation due to severe chronic anemia and local presence of hematopoietic growth factors and/or cytokines.

  12. CREB: A Key Regulator of Normal and Neoplastic Hematopoiesis

    Directory of Open Access Journals (Sweden)

    Salemiz Sandoval

    2009-01-01

    Full Text Available The cAMP response element-binding protein (CREB is a nuclear transcription factor downstream of cell surface receptors and mitogens that is critical for normal and neoplastic hematopoiesis. Previous work from our laboratory demonstrated that a majority of patients with acute myeloid leukemia (AML and acute lymphoid leukemia (ALL overexpress CREB in the bone marrow. To understand the role of CREB in leukemogenesis, we examined the biological effect of CREB overexpression on primary leukemia cells, leukemia cell lines, and CREB overexpressing transgenic mice. Our results demonstrated that CREB overexpression leads to an increase in cellular proliferation and survival. Furthermore, CREB transgenic mice develop a myeloproliferative disorder with aberrant myelopoiesis in both the bone marrow and spleen. Additional research from other groups has shown that the expression of the cAMP early inducible repressor (ICER, a CREB repressor, is also deregulated in leukemias. And, miR-34b, a microRNA that negative regulates CREB expression, is expressed at lower levels in myeloid leukemia cell lines compared to that of healthy bone marrow. Taken together, these data suggest that CREB plays a role in cellular transformation. The data also suggest that CREB-specific signaling pathways could possibly serve as potential targets for therapeutic intervention.

  13. No Arithmetic Cyclic Quadrilaterals

    Science.gov (United States)

    Beauregard, Raymond A.

    2006-01-01

    A quadrilateral is arithmetic if its area is an integer and its sides are integers in an arithmetic progression, and it is cyclic if it can be inscribed in a circle. The author shows that no quadrilateral is both arithmetic and cyclic.

  14. Characterization of hematopoiesis in Dabry's sturgeon (Acipenser dabryanus

    Directory of Open Access Journals (Sweden)

    Ya Liu

    2017-11-01

    Full Text Available The hematological indices of Dabry's sturgeon (Acipenser dabryanus were investigated in this paper. The results showed that the count of Red blood cell (RBC was (0.60 ± 0.02 × 1012/L, and the blood glucose (GLU was 9.32 ± 1.00 mmol/L. Glutamic-pyruvic transaminase (ALT and glutamic-oxalacetic transaminase (AST were 13.75 ± 6.65 U/L and 359.50 ± 40.07 U/L, respectively. Smears of peripheral blood and imprints of four tissues were studied in the trial with Wright's staining method. The results indicated that Dabry's sturgeon's blood cells could be divided into five cell types, and included erythroid, granuloid, monocytoid, lymphoid and other cells. In addition, the developmental stage of each cell lineage could be subdivided into: primitive, young and mature. In the three developmental stages, the size of each cell type was similar and gradually decreased from primitive, young to mature blood cells. Among the blood cells, the monoblast and macrophage were the biggest, while the thrombocyte was the smallest. All stages of the primitive cells and young cells were observed in head kidney and all cell types, except granuloblasts, were identified in the head kidney. In contrast, primitive cells and young cells were not observed in the spleen or liver, and few orthochromatic erythroblasts were found in peripheral blood. It can be concluded that head kidney and trunk kidney are the primary organs of hematopoiesis in the Dabry's sturgeon.

  15. Renal Bleeding Due to Extramedullary Hematopoiesis in a Patient With Chronic Myelogenous Leukemia

    Directory of Open Access Journals (Sweden)

    Stephanie Zettner

    2014-11-01

    Full Text Available Chronic myelogenous leukemia (CML is a myeloproliferative disorder that normally presents in middle-aged adults. Renal infiltration and extramedullary hematopoiesis in renal tissue has been rarely reported. This case report presents a patient with CML and renal insufficiency who developed gross hematuria. Efforts at controlling the hematuria led to a cascade of events propelled by the underlying disorder that ultimately led to a radical nephrectomy, multiorgan failure, and prolonged hospitalization. We suggest that management of gross hematuria in clinically stable patients with CML, suspected of having extramedullary hematopoiesis, should prioritize treatment of the myeloproliferative disorder over efforts to control bleeding.

  16. Extramedullary plasmacytoma involving perirenal space accompanied by extramedullary hematopoiesis and amyloid deposition.

    Science.gov (United States)

    Mimura, Rie; Kamishima, Tamotsu; Kubota, Kanako C; Nakano, Fumihito; Yabe, Ichiro; Sasaki, Hidenao; Maruyama, Satoru; Shinohara, Nobuo; Harris, Ardene A; Haga, Hironori; Shirato, Hiroki; Terae, Satoshi

    2010-05-01

    A 62-year-old man was referred to us after unsuccessful treatment of bilateral weakness in his upper and lower extremities with paresthesia in both lower extremities. Computed tomography (CT) revealed soft tissue masses in the left kidney along the capsule and paraaortic region that were of relatively low attenuation with accompanying granular calcifications. Pathological diagnosis of the biopsy specimen was extramedullary plasmacytoma accompanied by extramedullary hematopoiesis and amyloid deposition. Although the CT findings correlated well with the pathological results, the case was extremely atypical for extramedullary plasmacytoma in respect to location and the accompaniment with extramedullary hematopoiesis.

  17. Renal Bleeding Due to Extramedullary Hematopoiesis in a Patient With Chronic Myelogenous Leukemia.

    Science.gov (United States)

    Zettner, Stephanie; Mistry, Sandeep G

    2014-11-01

    Chronic myelogenous leukemia (CML) is a myeloproliferative disorder that normally presents in middle-aged adults. Renal infiltration and extramedullary hematopoiesis in renal tissue has been rarely reported. This case report presents a patient with CML and renal insufficiency who developed gross hematuria. Efforts at controlling the hematuria led to a cascade of events propelled by the underlying disorder that ultimately led to a radical nephrectomy, multiorgan failure, and prolonged hospitalization. We suggest that management of gross hematuria in clinically stable patients with CML, suspected of having extramedullary hematopoiesis, should prioritize treatment of the myeloproliferative disorder over efforts to control bleeding.

  18. Real Topological Cyclic Homology

    DEFF Research Database (Denmark)

    Høgenhaven, Amalie

    The main topics of this thesis are real topological Hochschild homology and real topological cyclic homology. If a ring or a ring spectrum is equipped with an anti-involution, then it induces additional structure on the topological Hochschild homology spectrum. The group O(2) acts on the spectrum......, where O(2) is the semi-direct product of T, the multiplicative group of complex number of modulus 1, by the group G=Gal(C/R). We refer to this O(2)-spectrum as the real topological Hochschild homology. This generalization leads to a G-equivariant version of topological cyclic homology, which we call...... real topological cyclic homology. The first part of the thesis computes the G-equivariant homotopy type of the real topological cyclic homology of spherical group rings at a prime p with anti-involution induced by taking inverses in the group. The second part of the thesis investigates the derived G...

  19. Cyclical innovations and production

    OpenAIRE

    Greiner, Alfred

    1994-01-01

    Cyclical innovations and production : a formal model of the firm reflecting Schumpeterian ideas / Alfred Greiner and Horst Hanusch. - In: Innovation in technology, industries, and institutions / ed. by Yuichi Shionoya ... - Ann Arbor : Univ. of Michigan Press, 1994. - S. 157-169

  20. Cyclic nucleotides and radioresistnace

    International Nuclear Information System (INIS)

    Kulinskij, V.I.; Mikheeva, G.A.; Zel'manovich, B.M.

    1982-01-01

    The addition of glucose to meat-peptone broth does not change the radiosensitizing effect (RSE) of cAMP at the logarithmic phase (LP) and the radioprotective effect (RPE) at the stationary phase (SP), but sensitization, characteristic of cGMP, disappears in SP and turns into RPE in LP. Introduction of glucose into the broth for 20 min eliminates all the effects of both cyclic nucleotides in the cya + strain while cya - mutant exhibits RSE. RSE of both cyclic nucleotides is only manifested on minimal media. These data brought confirmation of the dependence of the influence of cyclic media. These data brought confirmation of the dependence of the influence of cyclic nucleotides on radioresistance upon the metabolic status of the cell [ru

  1. Extramedullary hematopoiesis: Elucidating the function of the hematopoietic stem cell niche (Review).

    Science.gov (United States)

    Yamamoto, Kouhei; Miwa, Yukako; Abe-Suzuki, Shiho; Abe, Shinya; Kirimura, Susumu; Onishi, Iichiroh; Kitagawa, Masanobu; Kurata, Morito

    2016-01-01

    Extramedullary hematopoiesis (EMH) occurs under various circumstances, including during embryonic/developmental periods, pathological status secondary to insufficient bone marrow function or ineffective hematopoiesis, in hematological disorders, for example malignancies, as well as stromal disorders of the bone. EMH is characterized by hematopoietic cell accumulations in multiple body locations. Common EMH locations observed in clinical and pathological practice include the spleen, liver, lymph nodes and para‑vertebral regions. Among the various organs associated with EMH, the spleen offers a unique site for evaluation of hematopoietic stem cell (HSC)/niche interactions, as this organ is one of the most common sites of EMH. However, the spleen does not have a major role in embryonic/developmental hematopoiesis. A recent study by our group revealed that circulating HSCs may be trapped by chemokine (C‑X‑C motif) ligand 12 (CXCL12)‑positive cells at the margin of sinuses near CXCL12‑positive endothelial cells, resulting in the initiation of the first step of EMH, which is a similar mechanism to bone marrow hematopoiesis. The present review briefly discusses the environment of EMH in extramedullary spaces in order to investigate the mechanisms underlying HSC maintenance, and aid the elucidation of the niche‑stem cell interactions that occur in the bone marrow.

  2. Hematopoiesis in 5-Fluorouracil-Treated Adenosine A(3) Receptor Knock-Out Mice

    Czech Academy of Sciences Publication Activity Database

    Hofer, Michal; Pospíšil, Milan; Dušek, L.; Hoferová, Zuzana; Komůrková, Denisa

    2015-01-01

    Roč. 64, č. 2 (2015), s. 255-262 ISSN 0862-8408 Institutional support: RVO:68081707 Keywords : Adenosine A(3) receptor knock-out mice * Hematopoiesis * 5-fluorouracil-induced hematotoxicity Subject RIV: BO - Biophysics Impact factor: 1.643, year: 2015

  3. Clinical analysis of hematopoiesis reconstruction after total body irradiation in hematopoietic stem cell transplantation

    International Nuclear Information System (INIS)

    Fang Tong; Gao Hong; Sun Baojing; Chen Li

    2008-01-01

    Objective: To analyze the clinical outcome of total body irradiation in hematopoiesis reconstruction after autologous and allogeneic hematopoietic stem cell transplantation. Methods: 35 patients received autologous hematopoietic stem cell transplantation (ASCT group) and 35 patients received allogeneic hematopoietic stem cell transplantation (Allo-HSCT group) were enrolled in this study. And their hematopoiesis reconstruction were observed and analyzed. Results: The recovery time of ANC were 14 and 16 d, respectively, and the recovery time of PLT were 23 and 27 d, respectively, the difference were not significant (P>0.05) in ASCT group and Allo-HSCT group. But for both group, hematopoiesis reconstruction were faster in peripheral blood stem cell transplant than those in bone marrow transplant (P<0.05). The recovery time of PLT with the patients of total body irradiation dose ≥ 10 Gy were longer than those of < 10 Gy. Conclusions: At the same doses, the clinical outcome of hematopoiesis reconstruction of ASCT is similar to that of Allo-HSCT. But the recovery time in peripheral blood stem cell transplantation is faster than that in bone marrow transplant. The recovery time of PLT has relation with the irradiation dose. (authors)

  4. Peritoneal carcinomatosis-like implants of extramedullary hematopoiesis. An insolite occurrence during splenectomy for myelofibrosis

    Directory of Open Access Journals (Sweden)

    Marco Casaccia

    Full Text Available Introduction: Primary myelofibrosis (MF is a myeloproliferative neoplasm that results in debilitating constitutional symptoms, splenomegaly, and cytopenias. In patients with symptomatic splenomegaly, splenectomy remains a viable treatment option for MF patients with medically refractory symptomatic splenomegaly that precludes the use of ruxolitinib. Case presentation: We present the clinical case of a patient who was admitted to our Department to perform a splenectomy in MF as a therapeutic step prior to an allogeneic stem cell transplantation (ASCT. A laparotomic splenectomy and excision of whitish wide-spread peritoneal and omental nodulations was performed. There were no operative complications and the surgery was completed with minimal blood loss. The histopathological exam revealed an extramedullary hematopoiesis in both spleen and peritoneal nodules. Conclusion: In primary myelofibrosis it must always be kept in mind the possible presence of peritoneal implants of extramedullary hematopoiesis and ascites of reactive genesis. We report a rare case of peritoneal carcinomatosis-like implants of extramedullary hematopoiesis found at splenectomy for MF. Keywords: Myelofibrosis, Splenomegaly, Splenectomy, Extramedullary hematopoiesis

  5. A non-canonical function of zebrafish telomerase reverse transcriptase is required for developmental hematopoiesis.

    Directory of Open Access Journals (Sweden)

    Shintaro Imamura

    Full Text Available Although it is clear that telomerase expression is crucial for the maintenance of telomere homeostasis, there is increasing evidence that the TERT protein can have physiological roles that are independent of this central function. To further examine the role of telomerase during vertebrate development, the zebrafish telomerase reverse transcriptase (zTERT was functionally characterized. Upon zTERT knockdown, zebrafish embryos show reduced telomerase activity and are viable, but develop pancytopenia resulting from aberrant hematopoiesis. The blood cell counts in TERT-depleted zebrafish embryos are markedly decreased and hematopoietic cell differentiation is impaired, whereas other somatic lineages remain morphologically unaffected. Although both primitive and definitive hematopoiesis is disrupted by zTERT knockdown, the telomere lengths are not significantly altered throughout early development. Induced p53 deficiency, as well as overexpression of the anti-apoptotic proteins Bcl-2 and E1B-19K, significantly relieves the decreased blood cells numbers caused by zTERT knockdown, but not the impaired blood cell differentiation. Surprisingly, only the reverse transcriptase motifs of zTERT are crucial, but the telomerase RNA-binding domain of zTERT is not required, for rescuing complete hematopoiesis. This is therefore the first demonstration of a non-canonical catalytic activity of TERT, which is different from "authentic" telomerase activity, is required for during vertebrate hematopoiesis. On the other hand, zTERT deficiency induced a defect in hematopoiesis through a potent and specific effect on the gene expression of key regulators in the absence of telomere dysfunction. These results suggest that TERT non-canonically functions in hematopoietic cell differentiation and survival in vertebrates, independently of its role in telomere homeostasis. The data also provide insights into a non-canonical pathway by which TERT functions to modulate

  6. Generalized Wideband Cyclic MUSIC

    Directory of Open Access Journals (Sweden)

    Zhang-Meng Liu

    2009-01-01

    Full Text Available The method of Spectral Correlation-Signal Subspace Fitting (SC-SSF fails to separate wideband cyclostationary signals with coherent second-order cyclic statistics (SOCS. Averaged Cyclic MUSIC (ACM method made up for the drawback to some degree via temporally averaging the cyclic cross-correlation of the array output. This paper interprets ACM from another perspective and proposes a new DOA estimation method by generalizing ACM for wideband cyclostationary signals. The proposed method successfully makes up for the aforementioned drawback of SC-SSF and obtains a more satisfying performance than ACM. It is also demonstrated that ACM is a simplified form of the proposed method when only a single spectral frequency is exploited, and the integration of the frequencies within the signal bandwidth helps the new method to outperform ACM.

  7. Bone Marrow Micro-Environment in Normal and Deranged Hematopoiesis: Opportunities for Regenerative Medicine and Therapies.

    Science.gov (United States)

    Sarkaria, Shawn M; Decker, Matthew; Ding, Lei

    2018-03-01

    Various cell types cooperate to create a highly organized and dynamic micro-environmental niche in the bone marrow. Over the past several years, the field has increasingly recognized the critical roles of the interplay between bone marrow environment and hematopoietic cells in normal and deranged hematopoiesis. These advances rely on several new technologies that have allowed us to characterize the identity and roles of these niches in great detail. Here, we review the progress of the last several years, list some of the outstanding questions in the field and propose ways to target the diseased environment to better treat hematologic diseases. Understanding the extrinsic regulation by the niche will help boost hematopoiesis for regenerative medicine. Based on natural development of hematologic malignancies, we propose that combinatory targeting the niche and hematopoietic intrinsic mechanisms in early stages of hematopoietic malignancies may help eliminate minimal residual disease and have the highest efficacy. © 2018 WILEY Periodicals, Inc.

  8. Engraftment and reconstitution of hematopoiesis is dependent on VEGFR2-mediated regeneration of sinusoidal endothelial cells.

    Science.gov (United States)

    Hooper, Andrea T; Butler, Jason M; Nolan, Daniel J; Kranz, Andrea; Iida, Kaoruko; Kobayashi, Mariko; Kopp, Hans-Georg; Shido, Koji; Petit, Isabelle; Yanger, Kilangsungla; James, Daylon; Witte, Larry; Zhu, Zhenping; Wu, Yan; Pytowski, Bronislaw; Rosenwaks, Zev; Mittal, Vivek; Sato, Thomas N; Rafii, Shahin

    2009-03-06

    Myelosuppression damages the bone marrow (BM) vascular niche, but it is unclear how regeneration of bone marrow vessels contributes to engraftment of transplanted hematopoietic stem and progenitor cells (HSPCs) and restoration of hematopoiesis. We found that chemotherapy and sublethal irradiation induced minor regression of BM sinusoidal endothelial cells (SECs), while lethal irradiation induced severe regression of SECs and required BM transplantation (BMT) for regeneration. Within the BM, VEGFR2 expression specifically demarcated a continuous network of arterioles and SECs, with arterioles uniquely expressing Sca1 and SECs uniquely expressing VEGFR3. Conditional deletion of VEGFR2 in adult mice blocked regeneration of SECs in sublethally irradiated animals and prevented hematopoietic reconstitution. Similarly, inhibition of VEGFR2 signaling in lethally irradiated wild-type mice rescued with BMT severely impaired SEC reconstruction and prevented engraftment and reconstitution of HSPCs. Therefore, regeneration of SECs via VEGFR2 signaling is essential for engraftment of HSPCs and restoration of hematopoiesis.

  9. p53 Mediates Failure of Human Definitive Hematopoiesis in Dyskeratosis Congenita

    Directory of Open Access Journals (Sweden)

    Wilson Chun Fok

    2017-08-01

    Full Text Available Dyskeratosis congenita (DC is a bone marrow failure syndrome associated with telomere dysfunction. The progression and molecular determinants of hematopoietic failure in DC remain poorly understood. Here, we use the directed differentiation of human embryonic stem cells harboring clinically relevant mutations in telomerase to understand the consequences of DC-associated mutations on the primitive and definitive hematopoietic programs. Interestingly, telomere shortening does not broadly impair hematopoiesis, as primitive hematopoiesis is not impaired in DC cells. In contrast, while phenotypic definitive hemogenic endothelium is specified, the endothelial-to-hematopoietic transition is impaired in cells with shortened telomeres. This failure is caused by DNA damage accrual and is mediated by p53 stabilization. These observations indicate that detrimental effects of telomere shortening in the hematopoietic system are specific to the definitive hematopoietic lineages. This work illustrates how telomere dysfunction impairs hematopoietic development and creates a robust platform for therapeutic discovery for treatment of DC patients.

  10. Cyclic Voltammograms from First Principles

    DEFF Research Database (Denmark)

    Karlberg, Gustav; Jaramillo, Thomas; Skulason, Egill

    2007-01-01

    Cyclic voltammetry is a fundamental experimental tool for characterizing electrochemical surfaces. Whereas cyclic voltammetry is widely used within the field of electrochemistry, a way to quantitatively and directly relate the cyclic voltammogram to ab initio calculations has been lacking, even f...

  11. Pecular Features of Hematopoiesis in the Liver of Mature and Immature Green Frogs (Pelophylax Esculentus Complex

    Directory of Open Access Journals (Sweden)

    Akulenko N. M.

    2016-12-01

    Full Text Available The article describes characteristic features of the hematopoiesis in mature and immature green frogs (Pelophylax esculentus complex. Quantitative differences in liver myelograms were insignificant. However, in a sample of mature animals numerous significant correlations between the number of pigment inclusions in the liver and indicators of erythropoiesis and myelopoiesis were observed. Those correlations were absent in the immature frogs. We concluded that aft er the frogs’ breeding a lack of plastic resources, in particular, hemosiderin remains up to the hibernation.

  12. Myelopathy due to Spinal Extramedullary Hematopoiesis in a Patient with Polycythemia Vera.

    Science.gov (United States)

    Ito, Shuhei; Fujita, Nobuyuki; Hosogane, Naobumi; Nagoshi, Narihito; Yagi, Mitsuru; Iwanami, Akio; Watanabe, Kota; Tsuji, Takashi; Nakamura, Masaya; Matsumoto, Morio; Ishii, Ken

    2017-01-01

    Extramedullary hematopoiesis (EMH) occasionally occurs in patients exhibiting hematological disorders with decreased hematopoietic efficacy. EMH is rarely observed in the spinal epidural space and patients are usually asymptomatic. In particular, in the patients with polycythemia vera, spinal cord compression due to EMH is extremely rare. We report a case of polycythemia vera, in which operative therapy proved to be an effective treatment for myelopathy caused by spinal EMH.

  13. Cord Compression due to Extramedullary Hematopoiesis in an Adolescent with Known Beta Thalassemia Major

    OpenAIRE

    Soman, Salil; Rosenfeld, David L; Roychowdhury, Sudipta; Drachtman, Richard A; Cohler, Alan

    2009-01-01

    We describe a 16 year-old male with ß thalassemia major and gait disturbances that had not been given blood transfusions due to a severe childhood transfusion reaction. Thoracic spine MRI demonstrated hematopoietic marrow throughout the spine and epidural masses causing cord compression consistent with extramedullary hematopoiesis (EMH). After treatment with steroids, radiotherapy and monitored blood transfusions, the patient demonstrated significant improvement of his paraspinal lesions a...

  14. Myelopathy due to Spinal Extramedullary Hematopoiesis in a Patient with Polycythemia Vera

    Directory of Open Access Journals (Sweden)

    Shuhei Ito

    2017-01-01

    Full Text Available Extramedullary hematopoiesis (EMH occasionally occurs in patients exhibiting hematological disorders with decreased hematopoietic efficacy. EMH is rarely observed in the spinal epidural space and patients are usually asymptomatic. In particular, in the patients with polycythemia vera, spinal cord compression due to EMH is extremely rare. We report a case of polycythemia vera, in which operative therapy proved to be an effective treatment for myelopathy caused by spinal EMH.

  15. Myelopathy due to Spinal Extramedullary Hematopoiesis in a Patient with Polycythemia Vera

    OpenAIRE

    Ito, Shuhei; Fujita, Nobuyuki; Hosogane, Naobumi; Nagoshi, Narihito; Yagi, Mitsuru; Iwanami, Akio; Watanabe, Kota; Tsuji, Takashi; Nakamura, Masaya; Matsumoto, Morio; Ishii, Ken

    2017-01-01

    Extramedullary hematopoiesis (EMH) occasionally occurs in patients exhibiting hematological disorders with decreased hematopoietic efficacy. EMH is rarely observed in the spinal epidural space and patients are usually asymptomatic. In particular, in the patients with polycythemia vera, spinal cord compression due to EMH is extremely rare. We report a case of polycythemia vera, in which operative therapy proved to be an effective treatment for myelopathy caused by spinal EMH.

  16. Renal Bleeding Due to Extramedullary Hematopoiesis in a Patient With Chronic Myelogenous Leukemia

    OpenAIRE

    Stephanie Zettner; Sandeep G. Mistry

    2014-01-01

    Chronic myelogenous leukemia (CML) is a myeloproliferative disorder that normally presents in middle-aged adults. Renal infiltration and extramedullary hematopoiesis in renal tissue has been rarely reported. This case report presents a patient with CML and renal insufficiency who developed gross hematuria. Efforts at controlling the hematuria led to a cascade of events propelled by the underlying disorder that ultimately led to a radical nephrectomy, multiorgan failure, and prolonged hospital...

  17. Treatment with hydroxyurea in thalassemia intermedia with paravertebral pseudotumors of extramedullary hematopoiesis.

    Science.gov (United States)

    Cario, H; Wegener, M; Debatin, K-M; Kohne, E

    2002-08-01

    Excessive ineffective erythropoiesis in thalassemia intermedia may cause paravertebral pseudotumors of extramedullary hematopoiesis. Due to the proximity to the spinal canal, these paravertebral masses carry the risk of severe neurological damage. Treatment strategies include hypertransfusion, radiotherapy, and laminectomy. Hydroxyurea, stimulating fetal hemoglobin synthesis, may represent an alternative therapeutic approach. We report on a 26-year-old patient suffering from thalassemia intermedia with progressive anemia symptoms and presenting multiple intrathoracic paravertebral pseudotumors of extramedullary hematopoiesis. Hypertransfusion therapy and splenectomy were followed by regular transfusion (baseline hemoglobin 10 g/dl) and chelation with desferrioxamine. With this treatment, clinical symptoms disappeared, paravertebral hematopoietic masses did not progress, but severe hemosiderosis developed within a few years. Hydroxyurea therapy was initiated to increase the efficacy of erythropoiesis, thereby reducing the required transfusion volume but suppressing concomitantly further expansion of extramedullary hematopoiesis, and finally leading to a reduction of transfusional iron load. Treatment was started with 4 mg/kg per day and stepwise increased to 12.5 mg/kg per day. The fetal hemoglobin concentration increased from 4.5 to 5.5 g/dl after 1 year and to 9.9 g/dl after 2 years of treatment. The yearly transfusion volume was halved during the 1st year of treatment. At present, after 26 months of treatment, the patient has been transfusion-independent for 10 months. Serum ferritin levels decreased from 2844 to 1335 ng/ml. Size and shape of paravertebral hematopoietic pseudotumors remained stable. No side effects of hydroxyurea have been observed. In thalassemia intermedia patients with extramedullary hematopoiesis, hydroxyurea may lead to independence from regular transfusion therapy without further expansion of ectopic hematopoietic tissue.

  18. A Rare Presentation of Extramedullary Hematopoiesis in Post-polycythemic Myelofibrosis

    OpenAIRE

    Konca Degertekin, Ceyla; Özkurt, Zübeyde Nur; Akyürek, Nalan; Yağcı, Münci

    2012-01-01

    Polycythemia vera is a clonal proliferative disorder of the bone marrow that could possibly evolve into myelofibrosis in its natural course. Progression to myelofibrosis is usually a late stage complication and presents clinically with refractory cytopenias and extramedullary hematopoiesis (EMH). EMH can occur in any tissue during the course of post-polycythemic myelofibrosis. However, skin and cardiac involvements seems to be very rare. We present a 56-year-old woman with post-polycythemic m...

  19. Zinc finger protein 148 is dispensable for primitive and definitive hematopoiesis in mice.

    Directory of Open Access Journals (Sweden)

    Anna Nilton

    Full Text Available Hematopoiesis is regulated by transcription factors that induce cell fate and differentiation in hematopoietic stem cells into fully differentiated hematopoietic cell types. The transcription factor zinc finger protein 148 (Zfp148 interacts with the hematopoietic transcription factor Gata1 and has been implicated to play an important role in primitive and definitive hematopoiesis in zebra fish and mouse chimeras. We have recently created a gene-trap knockout mouse model deficient for Zfp148, opening up for analyses of hematopoiesis in a conventional loss-of-function model in vivo. Here, we show that Zfp148-deficient neonatal and adult mice have normal or slightly increased levels of hemoglobin, hematocrit, platelets and white blood cells, compared to wild type controls. Hematopoietic lineages in bone marrow, thymus and spleen from Zfp148 (gt/gt mice were further investigated by flow cytometry. There were no differences in T-cells (CD4 and CD8 single positive cells, CD4 and CD8 double negative/positive cells in either organ. However, the fraction of CD69- and B220-positive cells among lymphocytes in spleen was slightly lower at postnatal day 14 in Zfp148 (gt/gt mice compared to wild type mice. Our results demonstrate that Zfp148-deficient mice generate normal mature hematopoietic populations thus challenging earlier studies indicating that Zfp148 plays a critical role during hematopoietic development.

  20. The Drosophila lymph gland is an ideal model for studying hematopoiesis.

    Science.gov (United States)

    Yu, Shichao; Luo, Fangzhou; Jin, Li Hua

    2017-11-27

    Hematopoiesis in Drosophila melanogaster occurs throughout the entire life cycle, from the embryo to adulthood. The healthy lymph gland, as a hematopoietic organ during the larval stage, can give rise to two mature types of hemocytes, plasmatocytes and crystal cells, which persist into the pupal and adult stages. Homeostasis of the lymph gland is tightly controlled by a series of conserved factors and signaling pathways, which also play key roles in mammalian hematopoiesis. Thus, revealing the hematopoietic mechanisms in Drosophila will advance our understanding of hematopoietic stem cells and their niche as well as leukemia in mammals. In addition, the lymph gland employs a battery of strategies to produce lamellocytes, another type of mature hemocyte, to fight against parasitic wasp eggs, making the lymph gland an important immunological organ. In this review, the developmental process of the lymph gland and the regulatory networks of hematopoiesis are summarized. Moreover, we outline the current knowledge and novel insight into homeostasis of the lymph gland. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Peritoneal carcinomatosis-like implants of extramedullary hematopoiesis. An insolite occurrence during splenectomy for myelofibrosis.

    Science.gov (United States)

    Casaccia, Marco; Fornaro, Rosario; Frascio, Marco; Palombo, Denise; Stabilini, Cesare; Firpo, Emma; Gianetta, Ezio

    2017-01-01

    Primary myelofibrosis (MF) is a myeloproliferative neoplasm that results in debilitating constitutional symptoms, splenomegaly, and cytopenias. In patients with symptomatic splenomegaly, splenectomy remains a viable treatment option for MF patients with medically refractory symptomatic splenomegaly that precludes the use of ruxolitinib. We present the clinical case of a patient who was admitted to our Department to perform a splenectomy in MF as a therapeutic step prior to an allogeneic stem cell transplantation (ASCT). A laparotomic splenectomy and excision of whitish wide-spread peritoneal and omental nodulations was performed. There were no operative complications and the surgery was completed with minimal blood loss. The histopathological exam revealed an extramedullary hematopoiesis in both spleen and peritoneal nodules. In primary myelofibrosis it must always be kept in mind the possible presence of peritoneal implants of extramedullary hematopoiesis and ascites of reactive genesis. We report a rare case of peritoneal carcinomatosis-like implants of extramedullary hematopoiesis found at splenectomy for MF. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  2. Identification of novel regulators of developmental hematopoiesis using Endoglin regulatory elements as molecular probes.

    Science.gov (United States)

    Nasrallah, Rabab; Fast, Eva M; Solaimani, Parham; Knezevic, Kathy; Eliades, Alexia; Patel, Rahima; Thambyrajah, Roshana; Unnikrishnan, Ashwin; Thoms, Julie; Beck, Dominik; Vink, Chris S; Smith, Aileen; Wong, Jason; Shepherd, Mairi; Kent, David; Roychoudhuri, Rahul; Paul, Fabian; Klippert, Julia; Hammes, Annette; Willnow, Thomas; Göttgens, Bertie; Dzierzak, Elaine; Zon, Leonard I; Lacaud, George; Kouskoff, Valerie; Pimanda, John E

    2016-10-13

    Enhancers are the primary determinants of cell identity, and specific promoter/enhancer combinations of Endoglin (ENG) have been shown to target blood and endothelium in the embryo. Here, we generated a series of embryonic stem cell lines, each targeted with reporter constructs driven by specific promoter/enhancer combinations of ENG, to evaluate their discriminative potential and value as molecular probes of the corresponding transcriptome. The Eng promoter (P) in combination with the -8/+7/+9-kb enhancers, targeted cells in FLK1 mesoderm that were enriched for blast colony forming potential, whereas the P/-8-kb enhancer targeted TIE2+/c-KIT+/CD41- endothelial cells that were enriched for hematopoietic potential. These fractions were isolated using reporter expression and their transcriptomes profiled by RNA-seq. There was high concordance between our signatures and those from embryos with defects at corresponding stages of hematopoiesis. Of the 6 genes that were upregulated in both hemogenic mesoderm and hemogenic endothelial fractions targeted by the reporters, LRP2, a multiligand receptor, was the only gene that had not previously been associated with hematopoiesis. We show that LRP2 is indeed involved in definitive hematopoiesis and by doing so validate the use of reporter gene-coupled enhancers as probes to gain insights into transcriptional changes that facilitate cell fate transitions. © 2016 by The American Society of Hematology.

  3. The zebrafish moonshine gene encodes transcriptional intermediary factor 1gamma, an essential regulator of hematopoiesis.

    Directory of Open Access Journals (Sweden)

    David G Ransom

    2004-08-01

    Full Text Available Hematopoiesis is precisely orchestrated by lineage-specific DNA-binding proteins that regulate transcription in concert with coactivators and corepressors. Mutations in the zebrafish moonshine (mon gene specifically disrupt both embryonic and adult hematopoiesis, resulting in severe red blood cell aplasia. We report that mon encodes the zebrafish ortholog of mammalian transcriptional intermediary factor 1gamma (TIF1gamma (or TRIM33, a member of the TIF1 family of coactivators and corepressors. During development, hematopoietic progenitor cells in mon mutants fail to express normal levels of hematopoietic transcription factors, including gata1, and undergo apoptosis. Three different mon mutant alleles each encode premature stop codons, and enforced expression of wild-type tif1gamma mRNA rescues embryonic hematopoiesis in homozygous mon mutants. Surprisingly, a high level of zygotic tif1gamma mRNA expression delineates ventral mesoderm during hematopoietic stem cell and progenitor formation prior to gata1 expression. Transplantation studies reveal that tif1gamma functions in a cell-autonomous manner during the differentiation of erythroid precursors. Studies in murine erythroid cell lines demonstrate that Tif1gamma protein is localized within novel nuclear foci, and expression decreases during erythroid cell maturation. Our results establish a major role for this transcriptional intermediary factor in the differentiation of hematopoietic cells in vertebrates.

  4. Domination, Eternal Domination, and Clique Covering

    Directory of Open Access Journals (Sweden)

    Klostermeyer William F.

    2015-05-01

    Full Text Available Eternal and m-eternal domination are concerned with using mobile guards to protect a graph against infinite sequences of attacks at vertices. Eternal domination allows one guard to move per attack, whereas more than one guard may move per attack in the m-eternal domination model. Inequality chains consisting of the domination, eternal domination, m-eternal domination, independence, and clique covering numbers of graph are explored in this paper.

  5. Late stages of hematopoiesis and B cell lymphopoiesis are regulated by α-synuclein, a key player in Parkinson’s disease

    OpenAIRE

    Xiao, Wenbin; Shameli, Afshin; Harding, Clifford V.; Meyerson, Howard J.; Maitta, Robert W.

    2014-01-01

    α-synuclein plays a crucial role in Parkinson’s disease and dementias defined as synucleinopathies. α-synuclein is expressed in hematopoietic and immune cells, but its functions in hematopoiesis and immune responses are unknown. We utilized α-synuclein−/− (KO) mice to investigate its role in hematopoiesis and B cell lymphopoiesis. We demonstrated hematologic abnormalities including mild anemia, smaller platelets, lymphopenia but relatively normal early hematopoiesis in KO mice compared to wil...

  6. Dynamics of cyclic machines

    CERN Document Server

    Vulfson, Iosif

    2015-01-01

    This book focuses on modern methods of oscillation analysis in machines, including cyclic action mechanisms (linkages, cams, steppers, etc.). It presents schematization techniques and mathematical descriptions of oscillating systems, taking into account the variability of the parameters and nonlinearities, engineering evaluations of dynamic errors, and oscillation suppression methods. The majority of the book is devoted to the development of new methods of dynamic analysis and synthesis for cyclic machines that form regular oscillatory systems with multiple duplicate modules.  There are also sections examining aspects of general engineering interest (nonlinear dissipative forces, systems with non-stationary constraints, impacts and pseudo-impacts in clearances, etc.)  The examples in the book are based on the widely used results of theoretical and experimental studies as well as engineering calculations carried out in relation to machines used in the textile, light, polygraphic and other industries. Particu...

  7. HOST liner cyclic facilities

    Science.gov (United States)

    Schultz, D.

    1983-01-01

    The HOST Liner Cyclic Program is utilizing two types of test apparatus, rectangular box rigs and a full annular rig. To date two quartz lamp cyclic box rigs have been tested and a third is to begin testing in late October 1983. The box rigs are used to evaluate 5x8 inch rectangular linear samples. A 21 inch diameter outer liner simulator is also being built up for testing beginning in April 1984. All rigs are atmospheric rigs. The first box rig, a three 6-kVA lamp installation, was operated under adverse conditions to determine feasibility of using quartz lamps for cyclic testing. This work was done in December 1981 and looked promising. The second box rig, again using three 6-kVA lamps, was operated to obtain instrumentation durability information and initial data input to a Finite Element Model. This limited test program was conducted in August 1983. Five test plates were run. Instrumentation consisted of strain gages, thermocouples and thermal paint. The strain gages were found to fail at 1200 F as expected though plates were heated to 1700 F. The third box rig, containing four 6-kVA lamps, is in build up for testing to begin in late October 1983. In addition to 33 percent greater power input, this rig has provision for 400 F backside line cooling air and a viewing port suitable for IR camera viewing. The casing is also water cooled for extended durability.

  8. Cosmic evolution in a cyclic universe

    International Nuclear Information System (INIS)

    Steinhardt, Paul J.; Turok, Neil

    2002-01-01

    Based on concepts drawn from the ekpyrotic scenario and M theory, we elaborate our recent proposal of a cyclic model of the universe. In this model, the universe undergoes an endless sequence of cosmic epochs which begin with the universe expanding from a 'big bang' and end with the universe contracting to a 'big crunch'. Matching from 'big crunch' to 'big bang' is performed according to the prescription recently proposed with Khoury, Ovrut and Seiberg. The expansion part of the cycle includes a period of radiation and matter domination followed by an extended period of cosmic acceleration at low energies. The cosmic acceleration is crucial in establishing the flat and vacuous initial conditions required for ekpyrosis and for removing the entropy, black holes, and other debris produced in the preceding cycle. By restoring the universe to the same vacuum state before each big crunch, the acceleration ensures that the cycle can repeat and that the cyclic solution is an attractor

  9. Cyclic approximation to stasis

    Directory of Open Access Journals (Sweden)

    Stewart D. Johnson

    2009-06-01

    Full Text Available Neighborhoods of points in $mathbb{R}^n$ where a positive linear combination of $C^1$ vector fields sum to zero contain, generically, cyclic trajectories that switch between the vector fields. Such points are called stasis points, and the approximating switching cycle can be chosen so that the timing of the switches exactly matches the positive linear weighting. In the case of two vector fields, the stasis points form one-dimensional $C^1$ manifolds containing nearby families of two-cycles. The generic case of two flows in $mathbb{R}^3$ can be diffeomorphed to a standard form with cubic curves as trajectories.

  10. Accelerated cyclic corrosion tests

    Directory of Open Access Journals (Sweden)

    Prošek T.

    2016-06-01

    Full Text Available Accelerated corrosion testing is indispensable for material selection, quality control and both initial and residual life time prediction for bare and painted metallic, polymeric, adhesive and other materials in atmospheric exposure conditions. The best known Neutral Salt Spray (NSS test provides unrealistic conditions and poor correlation to exposures in atmosphere. Modern cyclic accelerated corrosion tests include intermittent salt spray, wet and dry phases and eventually other technical phases. They are able to predict the material performance in service more correctly as documented on several examples. The use of NSS should thus be restricted for quality control.

  11. Sex-linked dominant

    Science.gov (United States)

    Inheritance - sex-linked dominant; Genetics - sex-linked dominant; X-linked dominant; Y-linked dominant ... can be either an autosomal chromosome or a sex chromosome. It also depends on whether the trait ...

  12. Cyclic generalized projection MRI.

    Science.gov (United States)

    Sarty, Gordon E

    2015-04-01

    Progress in the development of portable MRI hinges on the ability to use lightweight magnets that have non-uniform magnetic fields. An image encoding method and mathematical procedure for recovering the image from the NMR signal from non-uniform magnets with closed isomagnetic contours is given. Individual frequencies in an NMR signal from an object in a non-uniform magnetic field give rise to integrals of the object along contours of constant magnetic field: generalized projections. With closed isomagnetic field contours a simple, cyclic, direct reconstruction of the image from the generalized projections is possible when the magnet and RF transmit coil are held fixed relative to the imaged object while the RF receive coil moves. Numerical simulations, using the Shepp and Logan mathematical phantom, were completed to show that the mathematical method works and to illustrate numerical limitations. The method is numerically verified and exact reconstruction demonstrated for discrete mathematical image phantoms. Correct knowledge of the RF receive field is necessary or severe image distortions will result. The cyclic mathematical reconstruction method presented here will be useful for portable MRI schemes that use non-uniform magnets with closed isomagnetic contours along with mechanically or electronically moving the RF receive coils. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Domination versus disjunctive domination in graphs | Henning ...

    African Journals Online (AJOL)

    A dominating set in a graph G is a set S of vertices of G such that every vertex not in S is adjacent to a vertex of S. The domination number of G is the minimum cardinality of a dominating set of G. For a positive integer b, a set S of vertices in a graph G is a b-disjunctive dominating set in G if every vertex v not in S is adjacent ...

  14. Extramedullary Hematopoiesis in a Man With β-Thalassemia: An Uncommon Cause of an Adrenal Mass

    Directory of Open Access Journals (Sweden)

    Zeighami

    2015-06-01

    Full Text Available Introduction Extramedullary hematopoiesis (EMH commonly occurs in the spleen, liver and lymph nodes. Rare cases of EMH in the adrenal gland have been reported. Case Presentation We report the case of a 33-year-old man from the South of Iran suffering from major β-thalassemia, who underwent open left adrenalectomy and the histopathology revealed EMH. Conclusions In patients in which a history of hematologic disorders exists, careful imaging and hormonal assay should be done to certify a diagnosis of EMH. However, the surgical management becomes inevitable in certain cases.

  15. Incomplete paraplegia caused by extramedullary hematopoiesis in a patient with thalassemia intermedia.

    Science.gov (United States)

    Hisamud-Din, Nurhasyimah; Mustafah, Nadia Mohd; Fauzi, Aishah Ahmad; Hashim, Natiara Mohamad

    2017-01-01

    Extramedullary hematopoiesis (EMH) is the production of blood cell precursors outside the bone marrow that occur in various hematological diseases. In patients with thalassemia intermedia, ineffective erythropoiesis drives compensatory EMH in the liver, pancreas, pleura, spleen, ribs and spine. We describe a patient with thalassemia intermedia who presented with acute neurological symptoms caused by paraspinal EMH, which responded well to combination therapy of steroid, hypertransfusion, laminectomy and excision of pseudotumor and hydroxyurea therapy to boost the formation of fetal haemoglobin. Prompt recognition of EMH based on clinical presentation and typical radiological findings should be made. Early treatment is recommended to prevent irreversible damage to the spinal cord.

  16. Extramedullary hematopoiesis within the clivus: an unusual cause of lower cranial nerve palsy.

    Science.gov (United States)

    Reames, Davis L; Lindstrom, Katherine; Raghavan, Prashant; Jane, John

    2010-12-01

    We report one year follow up of a case of extramedullary hematopoiesis within the clivus. The imaging findings, brief clinical course, and endoscopic transphenoidal approach are described. A 29-year-old female with thalassemia developed worsening cranial nerve signs. After imaging studies discovered a large clival mass, she underwent endoscopic transphenoidal biopsy of the lesion. Neural compression from exuberant erythrogenesis within tissue normally quiescent of red blood cell production was found to be the etiology of her neural deficit. Treatment for this condition is generally non-operative unless significant neural compression is present. Radiotherapy and anti-neoplastic agents have been used with success.

  17. Extramedullary hematopoiesis of the conjunctiva presenting as active systemic disease in a patient with myelofibrosis.

    Science.gov (United States)

    Cuttler, Nirupa; Heidemann, David; Cendrowski, Christopher; Armin, Ali-Reza; Folberg, Robert

    2014-12-01

    To report the clinicopathological correlation of extramedullary hematopoiesis (EMH) of the conjunctiva in a patient with a history of myelofibrosis. Case report. Elevated pink conjunctival lesions developed bilaterally in a 73-year-old man who had been treated for myelofibrosis for 13 years. EMH was detected in the examination of tissue from the lesion of the inferior fornix of the right eye. The appearance of conjunctival lesions in a patient with myelofibrosis may indicate underlying pathology of EMH that may necessitate a change in systemic treatment of this condition.

  18. Intracranial involvement in extramedullary hematopoiesis: case report and review of the literature

    Energy Technology Data Exchange (ETDEWEB)

    Haidar, Salwa; Ortiz-Neira, Clara; Shroff, Manohar; Gilday, David; Blaser, Susan [Hospital for Sick Children, Department of Diagnostic Imaging, Toronto, ON (Canada)

    2005-06-01

    Intracranial involvement in extramedullary hematopoiesis (EMH) is rare, but it should be suspected in patients with myelofibrosis presenting with chronic severe headache. We present a 9-year-old girl with known myelofibrosis whose headaches were unresponsive to routine treatment. CT and MRI studies of the brain showed diffuse pachymeningeal thickening. CT examinations of the chest and abdomen had demonstrated bilateral thoracic paraspinal masses caused by EMH, suggesting the possibility that the intracranial involvement might also be related to EMH. The diagnosis was confirmed by sulfur colloid isotope scan. (orig.)

  19. Splenomegaly unresponsive to standard and salvage chemotherapy in Langerhans cell histiocytosis: a case of extramedullary hematopoiesis.

    Science.gov (United States)

    Christiansen, Ellen C; Ellwein, Marcine; Neglia, Joseph P

    2012-06-01

    Langerhans cell histiocytosis (LCH) is a proliferative disorder of dendritic cells which has evaded efforts to clearly define pathogenesis, diagnostic criteria, and therapeutic response markers. Strides have been made at classification with the recent development of a quantified score of disease severity. Splenic involvement is an indicator of poor prognosis, with spleen size its surrogate marker in evaluation and scoring. We describe a case of pediatric LCH with progressive splenomegaly despite treatment, which when examined at splenectomy revealed no LCH involvement but extramedullary hematopoiesis. These findings thus challenge our understanding of splenomegaly as a marker of disease. Copyright © 2011 Wiley Periodicals, Inc.

  20. Intracranial involvement in extramedullary hematopoiesis: case report and review of the literature

    International Nuclear Information System (INIS)

    Haidar, Salwa; Ortiz-Neira, Clara; Shroff, Manohar; Gilday, David; Blaser, Susan

    2005-01-01

    Intracranial involvement in extramedullary hematopoiesis (EMH) is rare, but it should be suspected in patients with myelofibrosis presenting with chronic severe headache. We present a 9-year-old girl with known myelofibrosis whose headaches were unresponsive to routine treatment. CT and MRI studies of the brain showed diffuse pachymeningeal thickening. CT examinations of the chest and abdomen had demonstrated bilateral thoracic paraspinal masses caused by EMH, suggesting the possibility that the intracranial involvement might also be related to EMH. The diagnosis was confirmed by sulfur colloid isotope scan. (orig.)

  1. Paraplegia due to extramedullary hematopoiesis in thalassemia treated successfully with radiation therapy.

    Science.gov (United States)

    Malik, Monica; Pillai, Lakshmi S; Gogia, Nidhi; Puri, Tarun; Mahapatra, M; Sharma, Daya Nand; Kumar, Rajat

    2007-03-01

    Spinal cord compression due to extramedullary hematopoiesis (EMH) is a rare complication of thalassemia and generally presents as paraparesis with sensory impairment. Complete paraplegia is extremely rare in EMH due to thalassemia although it is known to occur in polycythemia vera and sickle cell anemia. Treatment options mostly include surgery and/or radiotherapy. Whereas cases presenting with paraparesis have been treated with either surgery or radiotherapy with equal frequency and efficacy, almost all reported cases with paraplegia have been treated with surgery with or without radiation therapy. We hereby report a case of thalassemia intermedia with paraplegia treated successfully with radiotherapy.

  2. PET CT imaging in extramedullary hematopoiesis and lung cancer surprise in a case with thalassemia intermedia

    Directory of Open Access Journals (Sweden)

    Semra Paydaş

    2011-03-01

    Full Text Available Extramedullary hematopoiesis (EMH is the production of hematopoietic precursors outside the bone marrow cavity, and it causes mass effects according to its localization. Magnetic resonance imaging (MRI and/or computed tomography (CT scans are used most commonly to detect EMH foci. We report herein a case with thalassemia intermedia causing paravertebral mass associated with EMH detected by CT scan. We further evaluated the case with positron emission tomography (PET CT, and lung cancer, which was not revealed in the CT scan, was detected coincidentally.

  3. Temporal bone extramedullary hematopoiesis as a causeof pediatric bilateral conductive hearing loss:Case report and review of the literature.

    Science.gov (United States)

    Lanigan, Alexander; Fordham, M Taylor

    2017-06-01

    Extramedullary hematopoiesis occurs in children with hemoglobinopathy and chronic anemia. The liver and spleen are often affected first, but other foci can develop to support erythrocyte demand. We report a case of a nine-year-old with beta thalassemia and temporal bone extramedullary hematopoiesis causing ossicular fixation and bilateral conductive hearing loss. There is only one case in the literature describing this phenomenon in pediatric patients, and this is the first case report of bilateral hearing loss from this physiologic phenomenon. Otolaryngologists should consider this etiology in patients with chronic anemia and conductive hearing loss in the absence of otitis media. Published by Elsevier B.V.

  4. The arabidopsis cyclic nucleotide interactome

    KAUST Repository

    Donaldson, Lara Elizabeth

    2016-05-11

    Background Cyclic nucleotides have been shown to play important signaling roles in many physiological processes in plants including photosynthesis and defence. Despite this, little is known about cyclic nucleotide-dependent signaling mechanisms in plants since the downstream target proteins remain unknown. This is largely due to the fact that bioinformatics searches fail to identify plant homologs of protein kinases and phosphodiesterases that are the main targets of cyclic nucleotides in animals. Methods An affinity purification technique was used to identify cyclic nucleotide binding proteins in Arabidopsis thaliana. The identified proteins were subjected to a computational analysis that included a sequence, transcriptional co-expression and functional annotation analysis in order to assess their potential role in plant cyclic nucleotide signaling. Results A total of twelve cyclic nucleotide binding proteins were identified experimentally including key enzymes in the Calvin cycle and photorespiration pathway. Importantly, eight of the twelve proteins were shown to contain putative cyclic nucleotide binding domains. Moreover, the identified proteins are post-translationally modified by nitric oxide, transcriptionally co-expressed and annotated to function in hydrogen peroxide signaling and the defence response. The activity of one of these proteins, GLYGOLATE OXIDASE 1, a photorespiratory enzyme that produces hydrogen peroxide in response to Pseudomonas, was shown to be repressed by a combination of cGMP and nitric oxide treatment. Conclusions We propose that the identified proteins function together as points of cross-talk between cyclic nucleotide, nitric oxide and reactive oxygen species signaling during the defence response.

  5. Cyclic transfers in school timetabling

    NARCIS (Netherlands)

    Post, Gerhard F.; Ahmadi, Samad; Geertsema, Frederik

    2012-01-01

    In this paper we propose a neighbourhood structure based on sequential/cyclic moves and a cyclic transfer algorithm for the high school timetabling problem. This method enables execution of complex moves for improving an existing solution, while dealing with the challenge of exploring the

  6. Cyclic transfers in school timetabling

    NARCIS (Netherlands)

    Post, Gerhard F.; Ahmadi, Samad; Geertsema, Frederik

    In this paper we propose a neighbourhood structure based on sequential/cyclic moves and a Cyclic Transfer algorithm for the high school timetabling problem. This method enables execution of complex moves for improving an existing solution, while dealing with the challenge of exploring the

  7. Manual for Cyclic Triaxial Test

    DEFF Research Database (Denmark)

    Shajarati, Amir; Sørensen, Kris Wessel; Nielsen, Søren Kjær

    This manual describes the different steps that is included in the procedure for conducting a cyclic triaxial test at the geotechnical Laboratory at Aalborg University. Furthermore it contains a chapter concerning some of the background theory for the static triaxial tests. The cyclic/dynamic tria......This manual describes the different steps that is included in the procedure for conducting a cyclic triaxial test at the geotechnical Laboratory at Aalborg University. Furthermore it contains a chapter concerning some of the background theory for the static triaxial tests. The cyclic....../dynamic triaxial cell is overall constructed in the same way as the static triaxial cell at Aalborg University, but with the ability to apply any kind of load sequence to the test sample. When conducting cyclic triaxial tests, it is recommended that the manual is followed very tediously since there are many steps...

  8. Impaired Hematopoiesis and Disrupted Monocyte/Macrophage Homeostasis in Mucopolysaccharidosis Type I Mice.

    Science.gov (United States)

    Viana, Gustavo Monteiro; Buri, Marcus Vinícius; Paredes-Gamero, Edgar Julian; Martins, Ana Maria; D'Almeida, Vânia

    2016-03-01

    Mucopolysaccharidosis type I (MPS I) is a rare autosomal recessive disease caused by alpha-L-iduronidase deficiency in which heparan and dermatan sulfate degradation is compromised. Besides primary lysosomal glycosaminoglycan accumulation, further changes in cellular functions have also been described in several murine MPS models. Herein, we evaluated alterations in hematopoiesis and its implications on the production of mature progeny in a MPS I murine model. Despite the significant increase in hematopoietic stem cells, a reduction in common myeloid progenitors and granulocyte-macrophage progenitor cells was observed in Idua -/- mice bone marrow. Furthermore, no alterations in number, viability nor activation of cell death mechanisms were observed in Idua -/- mice mature macrophages but they presented higher sensitivity to apoptotic induction after staurosporine treatment. In addition, changes in Ca(2+) signaling and a reduction in phagocytosis ability were also found. In summary, our results revealed significant intracellular changes in mature Idua -/- macrophages related to alterations in Idua -/- mice hematopoiesis, revealing a disruption in cell homeostasis. These results provide new insights into physiopathology of MPS I. © 2015 Wiley Periodicals, Inc.

  9. Engraftment and reconstitution of hematopoiesis is dependent on VEGFR2 mediated regeneration of sinusoidal endothelial cells

    Science.gov (United States)

    Hooper, Andrea T.; Butler, Jason M.; Nolan, Daniel J; Kranz, Andrea; Iida, Kaoruko; Kobayashi, Mariko; Kopp, Hans-Georg; Shido, Koji; Petit, Isabelle; Yanger, Kilangsungla; James, Daylon; Witte, Larry; Zhu, Zhenping; Wu, Yan; Pytowski, Bronislaw; Rosenwaks, Zev; Mittal, Vivek; Sato, Thomas N.; Rafii, Shahin

    2011-01-01

    SUMMARY The phenotypic attributes and molecular determinants for the regeneration of bone marrow (BM) sinusoidal endothelial cells (SECs) and their contribution to hematopoiesis are unknown. We show that after myelosuppression VEGFR2 activation promotes reassembly of regressed SECs, reconstituting hematopoietic stem and progenitor cells (HSPCs). VEGFR2 and VEGFR3 expression are restricted to BM vasculature, demarcating a continuous network of VEGFR2+VEGFR3+Sca1− SECs and VEGFR2+VEGFR3−Sca1+ arterioles. While chemotherapy (5FU) and sublethal irradiation (650 rad) induce minor SEC regression, lethal irradiation (950 rad) induces severe regression of SECs requiring BM transplantation (BMT) for regeneration. Conditional deletion of VEGFR2 in adult mice blocks regeneration of SECs in sublethally irradiated animals, preventing hematopoietic reconstitution. Inhibition of VEGFR2 signaling in lethally irradiated wild type mice rescued with BMT severely impairs SEC reconstruction, preventing engraftment and reconstitution of HSPCs. Therefore, activation of VEGFR2 is critical for regeneration of VEGFR3+Sca1− SECs that are essential for engraftment and restoration of HSPCs and hematopoiesis. PMID:19265665

  10. Ectopic osteogenesis and hematopoiesis after implantantion of bone marrow cells seeded on HAP/PLLA scaffold

    Directory of Open Access Journals (Sweden)

    Vasiljević Perica J.

    2009-01-01

    Full Text Available Bone tissue reconstruction and reparation is a big challenge in medicine. Biocomposite materials based on hidroxyapatite are widely used in reparation of bone defects. Adult bone marrow-derived stem cells may be considered in two categories: hematopoietic stem cells (HSC from the bone marrow and mesenchymal stem cells from the bone marrow stroma (BMSC. HSC and BMSC do not only coexist in one organ, but functionally cooperate. BMSC have a critical role in the formation of hematopoietic microenvironment (HME. The aim of this study was to investigate the interactions between bone marrow cells and biocomposites based on HAp/PLLA (hidroxyapatite/poly-L-lactide after subcutaneous implantation in Balb/c mice. In that purpose, bone marrow cells of Balb/c mice were seeded in HAp/PLLA tubes (15 mm×1,5 mm. The HAp/PLLA tubes with BMC was subcutaneously implanted with a needle into the intrascapsular region of the mouse. Implants were extracted after 2, 6 and 12 weeks. In implants after 2 and 6 weeks we found angiogenesis, collagenogenesis and new bone. Ectopic hematopoiesis was seen in implants after 12 weeks from implantation. As a good scaffold in the role of supporting osteogenesis and hematopoiesis, biocomposites HAp/PLLA can be good bone substitute materials in the bone reparation process. These results showed that the HAp/PLLA scaffold owned biological properties comparable to natural bone.

  11. Role of Vitamin A/Retinoic Acid in Regulation of Embryonic and Adult Hematopoiesis

    Directory of Open Access Journals (Sweden)

    Ana Cañete

    2017-02-01

    Full Text Available Vitamin A is an essential micronutrient throughout life. Its physiologically active metabolite retinoic acid (RA, acting through nuclear retinoic acid receptors (RARs, is a potent regulator of patterning during embryonic development, as well as being necessary for adult tissue homeostasis. Vitamin A deficiency during pregnancy increases risk of maternal night blindness and anemia and may be a cause of congenital malformations. Childhood Vitamin A deficiency can cause xerophthalmia, lower resistance to infection and increased risk of mortality. RA signaling appears to be essential for expression of genes involved in developmental hematopoiesis, regulating the endothelial/blood cells balance in the yolk sac, promoting the hemogenic program in the aorta-gonad-mesonephros area and stimulating eryrthropoiesis in fetal liver by activating the expression of erythropoietin. In adults, RA signaling regulates differentiation of granulocytes and enhances erythropoiesis. Vitamin A may facilitate iron absorption and metabolism to prevent anemia and plays a key role in mucosal immune responses, modulating the function of regulatory T cells. Furthermore, defective RA/RARα signaling is involved in the pathogenesis of acute promyelocytic leukemia due to a failure in differentiation of promyelocytes. This review focuses on the different roles played by vitamin A/RA signaling in physiological and pathological mouse hematopoiesis duddurring both, embryonic and adult life, and the consequences of vitamin A deficiency for the blood system.

  12. Helical tomotherapy for extramedullary hematopoiesis involving the pericardium in a patient with chronic myeloid leukemia.

    Science.gov (United States)

    Toms, Daniel R; Cannick, Leander; Stuart, Robert K; Jenrette, Joseph M; Terwiliger, Lacy

    2010-07-01

    Extramedullary hematopoiesis (EMH) refers to the development of foci of hematopoiesis outside its normal location in the bone marrow. This occurs normally during fetal development but is abnormal postpartum. The most common sites of EMH are the spleen and liver. The phenomenon occurs in a number of disease states, notably in myelofibrosis, thalassemia, immune thrombocytopenic purpura, sickle cell anemia, polycythemia vera, and myelodysplastic syndrome. Affected patients often develop symptoms related to the location of the EMH. Reported treatments include red blood cell transfusions, surgical excision, decompressive laminectomy in cases of cord compression, chemotherapy, and irradiation. Radiation therapy is highly effective for treating hematopoietic tissue because such tissues are extremely radiosensitive. Megavoltage helical tomotherapy is a technical advance in the delivery of radiation therapy, allowing more conformal and precise treatments. The present case report describes a patient with the diagnosis of atypical chronic myeloid leukemia and myelofibrosis who subsequently developed EMH of the pericardium with effusion and tamponade. By utilizing tomotherapy we were able to treat the pericardium while sparing much of the myocardium. The patient tolerated treatment well without acute adverse effects. His symptoms were alleviated, but he died approximately 1 year later.

  13. 27-Hydroxycholesterol induces hematopoietic stem cell mobilization and extramedullary hematopoiesis during pregnancy.

    Science.gov (United States)

    Oguro, Hideyuki; McDonald, Jeffrey G; Zhao, Zhiyu; Umetani, Michihisa; Shaul, Philip W; Morrison, Sean J

    2017-09-01

    Extramedullary hematopoiesis (EMH) is induced during pregnancy to support rapid expansion of maternal blood volume. EMH activation requires hematopoietic stem cell (HSC) proliferation and mobilization, processes that depend upon estrogen receptor α (ERα) in HSCs. Here we show that treating mice with estradiol to model estradiol increases during pregnancy induced HSC proliferation in the bone marrow but not HSC mobilization. Treatment with the alternative ERα ligand 27-hydroxycholesterol (27HC) induced ERα-dependent HSC mobilization and EMH but not HSC division in the bone marrow. During pregnancy, 27HC levels increased in hematopoietic stem/progenitor cells as a result of CYP27A1, a cholesterol hydroxylase. Cyp27a1-deficient mice had significantly reduced 27HC levels, HSC mobilization, and EMH during pregnancy but normal bone marrow hematopoiesis and EMH in response to bleeding or G-CSF treatment. Distinct hematopoietic stresses thus induce EMH through different mechanisms. Two different ERα ligands, estradiol and 27HC, work together to promote EMH during pregnancy, revealing a collaboration of hormonal and metabolic mechanisms as well as a physiological function for 27HC in normal mice.

  14. Effects of irradiation on the production of factors regulating humoral hematopoiesis

    International Nuclear Information System (INIS)

    Seki, Masatoshi; Yoshida, Kazuko

    1974-01-01

    Changes in factors regulating humoral hematopoiesis after irradiation were studied by intraperitoneal insertion of cellulose acetate membrane (CA membrane). There is little possibility that regulation factors is produced by macrophage itself. The growth of the colony depends mainly on increase or decrease of regulation factors in the host. However, there is a possibility that the macrophage interferes the action of these regulation factors. From the fact that there is no action of EPO (erythropoiesis) in Sl/slsup(d) mice having abnormal function of microenvironment, it is suggested that the action of EPO is brought about through the function of the microenvironment. In the analysis of the colony formation by intraperitoneal insertion of CA membrane, it is considered that the erythroblastic colony can be formed by the macrophage through the action of EPO. In short, it is concluded that factors regulating humoral hematopoiesis increased in the body of the mouse which have been irradiated to the whole body, and the increase in these factors is not constant, but remarkably changes with time. (Namekawa, K.)

  15. Vascular Platform to Define Hematopoietic Stem Cell Factors and Enhance Regenerative Hematopoiesis

    Directory of Open Access Journals (Sweden)

    Michael G. Poulos

    2015-11-01

    Full Text Available Hematopoietic stem cells (HSCs inhabit distinct microenvironments within the adult bone marrow (BM, which govern the delicate balance between HSC quiescence, self-renewal, and differentiation. Previous reports have proposed that HSCs localize to the vascular niche, comprised of endothelium and tightly associated perivascular cells. Herein, we examine the capacity of BM endothelial cells (BMECs to support ex vivo and in vivo hematopoiesis. We demonstrate that AKT1-activated BMECs (BMEC-Akt1 have a unique transcription factor/cytokine profile that supports functional HSCs in lieu of complex serum and cytokine supplementation. Additionally, transplantation of BMEC-Akt1 cells enhanced regenerative hematopoiesis following myeloablative irradiation. These data demonstrate that BMEC-Akt1 cultures can be used as a platform for the discovery of pro-HSC factors and justify the utility of BMECs as a cellular therapy. This technical advance may lead to the development of therapies designed to decrease pancytopenias associated with myeloablative regimens used to treat a wide array of disease states.

  16. 27-Hydroxycholesterol induces hematopoietic stem cell mobilization and extramedullary hematopoiesis during pregnancy

    Science.gov (United States)

    McDonald, Jeffrey G.; Shaul, Philip W.; Morrison, Sean J.

    2017-01-01

    Extramedullary hematopoiesis (EMH) is induced during pregnancy to support rapid expansion of maternal blood volume. EMH activation requires hematopoietic stem cell (HSC) proliferation and mobilization, processes that depend upon estrogen receptor α (ERα) in HSCs. Here we show that treating mice with estradiol to model estradiol increases during pregnancy induced HSC proliferation in the bone marrow but not HSC mobilization. Treatment with the alternative ERα ligand 27-hydroxycholesterol (27HC) induced ERα-dependent HSC mobilization and EMH but not HSC division in the bone marrow. During pregnancy, 27HC levels increased in hematopoietic stem/progenitor cells as a result of CYP27A1, a cholesterol hydroxylase. Cyp27a1-deficient mice had significantly reduced 27HC levels, HSC mobilization, and EMH during pregnancy but normal bone marrow hematopoiesis and EMH in response to bleeding or G-CSF treatment. Distinct hematopoietic stresses thus induce EMH through different mechanisms. Two different ERα ligands, estradiol and 27HC, work together to promote EMH during pregnancy, revealing a collaboration of hormonal and metabolic mechanisms as well as a physiological function for 27HC in normal mice. PMID:28783041

  17. Ada and cyclic runtime scheduling

    Science.gov (United States)

    Hood, Philip E.

    1986-01-01

    An important issue that must be faced while introducing Ada into the real time world is efficient and prodictable runtime behavior. One of the most effective methods employed during the traditional design of a real time system is the cyclic executive. The role cyclic scheduling might play in an Ada application in terms of currently available implementations and in terms of implementations that might be developed especially to support real time system development is examined. The cyclic executive solves many of the problems faced by real time designers, resulting in a system for which it is relatively easy to achieve approporiate timing behavior. Unfortunately a cyclic executive carries with it a very high maintenance penalty over the lifetime of the software that is schedules. Additionally, these cyclic systems tend to be quite fragil when any aspect of the system changes. The findings are presented of an ongoing SofTech investigation into Ada methods for real time system development. The topics covered include a description of the costs involved in using cyclic schedulers, the sources of these costs, and measures for future systems to avoid these costs without giving up the runtime performance of a cyclic system.

  18. Serial CT Findings of Resolving Extramedullary Hematopoiesis as Unilateral Posterior Mediastinal Mass after Splenectomy in Hereditary Spherocytosis: A Case Report

    International Nuclear Information System (INIS)

    Nam, Mi Yeon; Lee, Ju Won; Kim, Yeo Ju; Kim, Youn Jeong; Kang, Young Hye; Lee, Kyung Hee

    2012-01-01

    Intrathoracic extramedullary hematopoiesis (EMH) is a rare condition of the hereditary spherocytosis. EMH usually regresses or disappears after treatment; such as splenectomy in the case of spherocytosis. We report a case of hereditary spherocytosis. It is presented with an unilateral paravertebral posterior mediastinal mass. After splenectomy, it revealed shrinkage and fatty replacement on serial CT scans.

  19. Serial CT Findings of Resolving Extramedullary Hematopoiesis as Unilateral Posterior Mediastinal Mass after Splenectomy in Hereditary Spherocytosis: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Mi Yeon; Lee, Ju Won; Kim, Yeo Ju; Kim, Youn Jeong; Kang, Young Hye; Lee, Kyung Hee [Dept. of Radiology, Inha University Hospital, Incheon (Korea, Republic of)

    2012-03-15

    Intrathoracic extramedullary hematopoiesis (EMH) is a rare condition of the hereditary spherocytosis. EMH usually regresses or disappears after treatment; such as splenectomy in the case of spherocytosis. We report a case of hereditary spherocytosis. It is presented with an unilateral paravertebral posterior mediastinal mass. After splenectomy, it revealed shrinkage and fatty replacement on serial CT scans.

  20. Ectopic extramedullary hematopoiesis: evaluation and treatment of a rare and benign paraspinal/epidural tumor.

    Science.gov (United States)

    Mattei, Tobias A; Higgins, Michael; Joseph, Flynn; Mendel, Ehud

    2013-03-01

    Ectopic extramedullary hematopoiesis (EMH), defined as the formation of blood cells outside the bone marrow, usually occurs in a scenario of chronic anemia when, even after conversion of the bony yellow marrow to red marrow, the body is still unable to meet the demand for red blood cells. Ectopic extramedullary hematopoiesis most commonly occurs in the liver and spleen but may, in fact, occur almost anywhere in the body. Although previous reports have documented EMH presenting as paraspinal masses, such lesions have almost always been associated with a predisposing hematological disorder such as hemolytic anemia, myelofibrosis or myelodysplastic syndromes, thalassemia, polycythemia vera, leukemia, or lymphoma. The authors of this report describe the first reported instance of EMH in a patient presenting with a symptomatic epidural and paraspinal cervical lesion arising from the posterior spinal elements and no known predisposing hematological disease. Initial radiographs revealed a bony lesion arising posteriorly from the C2-3 laminae and spinous processes. Subsequent imaging suggested the diagnosis, which was confirmed by CT-guided biopsy, peripheral blood smears, and bone marrow aspirate. Despite epidural compression and slight displacement of the cervical cord and thecal sac, the patient's symptoms were limited to pain and diminished cervical range of motion. Therefore, surgery was deferred in favor of nonsurgical therapy. Several alternative modalities for the treatment of EMH have been suggested in the literature, including cytotoxic agents and radiotherapy. The authors opted for an approach utilizing directed low-dose radiotherapy of a total of 25 Gy divided in 2.5-Gy fractions. At the 3-month follow-up, the patient continued to be asymptomatic, and MRI demonstrated a significant reduction in the dimensions of the lesion. Extramedullary hematopoiesis with spinal cord compression in the absence of a preexisting hematological disorder has not been described in

  1. Prognosis of Cyclic Vomiting Syndrome

    Directory of Open Access Journals (Sweden)

    J. Gordon Millichap

    2016-03-01

    Full Text Available Investigators from Teikyo University School of Medicine, Tokyo, Japan, evaluated the clinical features, prognosis, and prophylaxis of cyclic vomiting syndrome and the relationship between the syndrome and levels of adrenocorticotropic/antidiuretic hormones (ACTH/ADH.

  2. Transcriptional regulation by cyclic AMP.

    Science.gov (United States)

    Montminy, M

    1997-01-01

    A number of hormones and growth factors have been shown to stimulate target cells via second messenger pathways that in turn regulate the phosphorylation of specific nuclear factors. The second messenger cyclic AMP, for example, regulates a striking number of physiologic processes, including intermediary metabolism, cellular proliferation, and neuronal signaling, by altering basic patterns of gene expression. Our understanding of cyclic AMP signaling in the nucleus has expanded considerably over the past decade, owing in large part to the characterization of cyclic AMP-responsive promoter elements, transcription factors that bind them, and signal-dependent coactivators that mediate target gene induction. More importantly, these studies have revealed new insights into biological problems as diverse as biological clocks and long-term memory. The purpose of this review is to describe the components of the cyclic AMP response unit and to analyze how these components cooperate to induce target gene expression in response to hormonal stimulation.

  3. Functionalized linear and cyclic polyolefins

    Science.gov (United States)

    Tuba, Robert; Grubbs, Robert H.

    2018-02-13

    This invention relates to methods and compositions for preparing linear and cyclic polyolefins. More particularly, the invention relates to methods and compositions for preparing functionalized linear and cyclic polyolefins via olefin metathesis reactions. Polymer products produced via the olefin metathesis reactions of the invention may be utilized for a wide range of materials applications. The invention has utility in the fields of polymer and materials chemistry and manufacture.

  4. Isolate domination in graphs

    Directory of Open Access Journals (Sweden)

    I. Sahul Hamid

    2016-07-01

    Full Text Available A set D of vertices of a graph G is called a dominating set of G if every vertex in V(G−D is adjacent to a vertex in D. A dominating set S such that the subgraph 〈S〉 induced by S has at least one isolated vertex is called an isolate dominating set. An isolate dominating set none of whose proper subset is an isolate dominating set is a minimal isolate dominating set. The minimum and maximum cardinality of a minimal isolate dominating set are called the isolate domination number γ0 and the upper isolate domination number Γ0 respectively. In this paper we initiate a study on these parameters.

  5. Intrathoracic extramedullary hematopoiesis: appearance on /sup 99m/Tc sulfur colloid marrow scan

    International Nuclear Information System (INIS)

    Bronn, L.J.; Paquelet, J.R.; Tetalman, M.R.

    1980-01-01

    Imaging of the bone marrow by radionuclide scanning was performed using colloids, which are phagocytized by the reticuloendothelial cells of the marrow, or radioiron, which is incorporated into reticulocytes. The use of the former radiopharmaceutical is based on the assumption, generally valid except in aplastic states or after irradiation, that the distribution of hematopoietic and reticuloendothelial tissue in the marrow is similar. Regardless of the method used, active adult marrow is normally distributed only in the axial skeleton and proximal humeri and femurs. Marrow imaging has been used in the evaluation of myeloproliferative disorders, leukemia, lymphoma, aplastic states, malignancy metastatic to marrow, and hemolytic anemia. We report a case of thalassemia major in which the diagnosis of intrathoracic extramedullary hematopoiesis was confirmed with the /sup 99m/Tc sulfur colloid bone marrow scan

  6. Cord Compression due to Extramedullary Hematopoiesis in an Adolescent with Known Beta Thalassemia Major

    Directory of Open Access Journals (Sweden)

    Alan COHLER

    2009-01-01

    Full Text Available We describe a 16 year-old male with ß thalassemia major and gait disturbances that had not been given blood transfusions due to a severe childhood transfusion reaction. Thoracic spine MRI demonstrated hematopoietic marrow throughout the spine and epidural masses causing cord compression consistent with extramedullary hematopoiesis (EMH. After treatment with steroids, radiotherapy and monitored blood transfusions, the patient demonstrated significant improvement of his paraspinal lesions and near complete resolution of his neurological symptoms. While EMH causing cord compression in adolescents is rare in the current era of bone marrow transplantation or chronic transfusions, it should be considered when thalassemia major patients present with neurological deficits. The well defined imaging features of EMH can play a central role in its diagnosis and management, especially because surgical and / or radiotherapeutic intervention are often considered in cases of failed medical treatment.

  7. Postnatal hematopoiesis and gut microbiota in NOD mice deviate from C57BL/6 mice

    DEFF Research Database (Denmark)

    Damlund, Dina Silke Malling; Metzdorff, Stine Broeng; Hasselby, Jane Preuss

    2016-01-01

    Neonatal studies in different mouse strains reveal that early life colonization affects the development of adaptive immunity in mice. The nonobese diabetic (NOD) mouse spontaneously develops autoimmune diabetes, but neonatal studies of NOD mice are lacking. We hypothesized that NOD mice deviate...... from another much used mouse strain, C57BL/6, with respect to postnatal microbiota and/or hematopoiesis and compared this in newborn mice of dams housed under the same conditions. A distinct bacteria profile rich in staphylococci was found at postnatal days (PND) 1-4 in NOD mice. Furthermore......, a distinct splenic cell profile high in a granulocytic phenotype was evident in the neonatal NOD mice whereas neonatal C57BL/6 mice showed a profile rich in monocytes. Neonatal expression of Reg3g and Muc2 in the gut was deviating in NOD mice and coincided with fewer bacteria attaching to the Mucosal surface...

  8. Extramedullary hematopoiesis with spinal cord compression in a child with thalassemia intermedia.

    Science.gov (United States)

    Ileri, Talia; Azik, Fatih; Ertem, Mehmet; Uysal, Zumrut; Gozdasoglu, Sevgi

    2009-09-01

    Spinal cord compression due to extramedullary hematopoiesis is an extremely rare complication of thalassemia intermedia. No cases with this complication have been reported in the first decade of life, because masses of heterotropic marrow developed in patients as a result of continuous erythropoiesis. We report the 9-year-old patient suffering from thalassemia intermedia and presenting spinal cord compression. We also review the literature about treatment options, because there is no consensus about the optimal treatment of these patients. Our patient was successfully treated with radiation therapy followed by hydroxyurea. With this combination therapy, he had no recurrence during the 4-year follow-up period. Clinical awareness of this phenomenon with the early treatment is essential for optimizing the successful outcome.

  9. Maxillofacial extramedullary hematopoiesis in a child with sickle cell presenting as bilateral periorbital cellulitis.

    Science.gov (United States)

    Reiersen, David A; Mandava, Mamatha; Jeroudi, Majed; Gungor, Anil

    2014-07-01

    Review of a case of paraosseous extramedullary hematopoiesis (EMH) affecting the maxillary sinuses and retro-orbital spaces imitating bilateral orbital cellulitis. Maxillofacial EMH causes diagnostic/therapeutic challenges. This case report describes a 4-year-old African American male with sickle cell disease (HbSS) who presented with bilateral orbitofacial swelling. Diagnosis was made with imaging and confirmed with tissue sampling. Partial exchange transfusion was utilized to stop the progression of maxillofacial EMH and to treat the patient's chronic anemia. Follow-up MRI showed regression of orbital and retro-orbital involvement. Early treatment with conservative modalities and close observation may prevent need for more invasive treatments. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  10. A Rare Presentation of Extramedullary Hematopoiesis in Post-polycythemic Myelofibrosis.

    Science.gov (United States)

    Konca Degertekin, Ceyla; Ozkurt, Zübeyde Nur; Akyürek, Nalan; Yağcı, Münci

    2014-09-01

    Polycythemia vera is a clonal proliferative disorder of the bone marrow that could possibly evolve into myelofibrosis in its natural course. Progression to myelofibrosis is usually a late stage complication and presents clinically with refractory cytopenias and extramedullary hematopoiesis (EMH). EMH can occur in any tissue during the course of post-polycythemic myelofibrosis. However, skin and cardiac involvements seems to be very rare. We present a 56-year-old woman with post-polycythemic myelofibrosis refractory to treatment, developing EMH after splenectomy in various organs, exceptionally the skin and the heart. Along with the case, the clinical presentations, treatment options, prognostic significance of EMH and the role of cytogenetics is discussed in the light of the literature.

  11. [Spinal cord compression due to extramedullary hematopoiesis in a patient with myelofibrosis].

    Science.gov (United States)

    Hijikata, Yasuhiro; Ando, Tetsuo; Inagaki, Tomonori; Watanabe, Hirohisa; Ito, Mizuki; Sobue, Gen

    2014-01-01

    Development and growth of hematopoietic tissue outside of the bone marrow is termed extramedullary hematopoiesis (EMH). It occurs in patients with hematological diseases such as myelofibrosis and thalassemia. Liver and spleen are the usual sites of EMH. However, spinal cord compression caused by EMH is a rare complication. A 65-year-old man with myelofibrosis was admitted to our hospital with progressive paraparesis. Thoracic spine MRI revealed epidural masses causing cord compression. Histological examination of the epidural mass showed evidence of EMH consisting of megakaryocytic and erythroid hyperplasia. After surgical decompression and radiotherapy, lower limb weakness and sensory disturbance were significantly improved. MRI showed disappearance of the spinal cord compression. With this therapy, he had no recurrence until he died of myelofibrosis. Spinal EMH should be considered as a differential diagnosis in patients with hematological diseases presenting with paraparesis. Surgical decompression and radiotherapy are effective approaches for the treatment of paraparesis due to EMH.

  12. Extramedullary hematopoiesis and paraplegia in a patient with hemoglobin e-Beta thalassemia.

    Science.gov (United States)

    Alam, M R; Habib, M S; Dhakal, G P; Khan, M R; Rahim, M A; Chowdhury, A J; Mahmud, T K

    2010-07-01

    Extramedullary hematopoiesis (EMH) occurs in patients with various hematologic disorders involving a chronic increase in the production of red blood cells, and is often associated polycythemia vera and sickle cell anaemia, but is less common with thalassemia especially with hemoglobin E-beta thalassemia. Spinal cord compression due to EMH is a extremely rare complication of thalassemia and may present with paraparesis or paraplegia with or without sensory impairment. Treatment options mostly include surgery and/or radiotherapy. Whereas cases presenting with paraplegia have been treated with either surgery or radiotherapy with equal frequency and efficacy, almost all reported cases with paraplegia have been treated with surgery with or without radiation therapy. We hereby report a case of hemoglobin E-beta thalassemia with paraplegia treated successfully with radiotherapy.

  13. Cord Compression due to Extramedullary Hematopoiesis in an Adolescent with Known Beta Thalassemia Major

    Science.gov (United States)

    Soman, Salil; Rosenfeld, David L; Roychowdhury, Sudipta; Drachtman, Richard A; Cohler, Alan

    2009-01-01

    We describe a 16 year-old male with β thalassemia major and gait disturbances that had not been given blood transfusions due to a severe childhood transfusion reaction. Thoracic spine MRI demonstrated hematopoietic marrow throughout the spine and epidural masses causing cord compression consistent with extramedullary hematopoiesis (EMH). After treatment with steroids, radiotherapy and monitored blood transfusions, the patient demonstrated significant improvement of his paraspinal lesions and near complete resolution of his neurological symptoms. While EMH causing cord compression in adolescents is rare in the current era of bone marrow transplantation or chronic transfusions, it should be considered when thalassemia major patients present with neurological deficits. The well defined imaging features of EMH can play a central role in its diagnosis and management, especially because surgical and / or radiotherapeutic intervention are often considered in cases of failed medical treatment. PMID:22470615

  14. The human protooncogene product p33pim is expressed during fetal hematopoiesis and in diverse leukemias

    International Nuclear Information System (INIS)

    Amson, R.; Przedborski, S.; Telerman, A.; Sigaux, F.; Flandrin, G.; Givol, D.

    1989-01-01

    The authors measured the human pim-1 protooncogene (PIM) expression during fetal development and in hematopoietic malignancies. The data indicate that during human fetal hematopoiesis the 33-kDa pim product, p33pim, is highly expressed in the liver and the spleen. In contrast, a the adult stage it is only slightly expressed in circulating granulocytes. Out of 70 hematopoietic malignancies analyzed, 51 patients and 19 cell lines, p33pim was overexpressed in ∼ 30% of the samples, particularly in myeloid and lymphoid acute leukemias. This overexpression was unrelated to any stage of cellular differentiation and was not due to gene rearrangement or amplification. These results imply a physiological role of the pim-1 protooncogene during hematopoietic development and a deregulation in various leukemias

  15. COMP-Ang1 Recovers Hematopoiesis after Gamma-ray Irradiation in Mice

    International Nuclear Information System (INIS)

    Lee, Hae-June; Lee, Yoon-Jin; Kwon, Hee-Choong; Lee, Su-Jae; Bae, Sang-Woo; Lee, Yun-Sil; Kim, Sung-Ho

    2006-01-01

    It has been reported that angiopoietin (Ang1) enhanced the ability of hematopoietic stem cells (HSCs) to become quiescent and induced adhesion to bone, resulting in protection of the HSC compartment from myleosuppressive stress. Ang1 activates Tie2 receptors expressed on the vascular endothelial cells and HSCs expressing the receptor tyrosine kinase Tie2 are quiescent and antiapoptotic, comprise a sidepopulation of HSCs. COMP-Ang1 is generated protein, is a soluble, stable, and potent Ang1 variant by replacing the N-terminal portion of Ang1 with short coiled-coil domain of cartilage oligomeric matrix protein (COMP). Radio- and chemotherapy induces considerable damage of bone marrow. Herein, by using COMP-Ang1, we investigated the effect of COMP-Ang1 on restoration of hematopoiesis in bone marrow against radiation-induced myelosuppression

  16. Topics on domination

    CERN Document Server

    Hedetniemi, ST

    1991-01-01

    The contributions in this volume are divided into three sections: theoretical, new models and algorithmic. The first section focuses on properties of the standard domination number &ggr;(G), the second section is concerned with new variations on the domination theme, and the third is primarily concerned with finding classes of graphs for which the domination number (and several other domination-related parameters) can be computed in polynomial time.

  17. Total well dominated trees

    DEFF Research Database (Denmark)

    Finbow, Arthur; Frendrup, Allan; Vestergaard, Preben D.

    cardinality then G is a total well dominated graph. In this paper we study composition and decomposition of total well dominated trees. By a reversible process we prove that any total well dominated tree can both be reduced to and constructed from a family of three small trees....

  18. Dominating Sets and Domination Polynomials of Paths

    Directory of Open Access Journals (Sweden)

    Saeid Alikhani

    2009-01-01

    Full Text Available Let G=(V,E be a simple graph. A set S⊆V is a dominating set of G, if every vertex in V\\S is adjacent to at least one vertex in S. Let 𝒫ni be the family of all dominating sets of a path Pn with cardinality i, and let d(Pn,j=|𝒫nj|. In this paper, we construct 𝒫ni, and obtain a recursive formula for d(Pn,i. Using this recursive formula, we consider the polynomial D(Pn,x=∑i=⌈n/3⌉nd(Pn,ixi, which we call domination polynomial of paths and obtain some properties of this polynomial.

  19. Transjugular Intrahepatic Porto-Systemic Stent-Shunt for Therapy of Bleeding Esophageal Varices Due to Extramedullary Hematopoiesis in Primary Myelofibrosis: A Case Report

    OpenAIRE

    Phillip, Veit;Berger, Hermann;Straub, Melanie;Saugel, Bernd;Treiber, Matthias;Einwächter, Henrik;Schmid, Roland M.;Huber, Wolfgang

    2016-01-01

    Background: Primary myelofibrosis belongs to the group of myeloproliferative syndromes. Extramedullary hematopoiesis in the liver can lead to portal hypertension. Patient and Methods: We report a case of a patient with life-threatening, endoscopically not treatable bleeding from esophageal varices due to extramedullary hematopoiesis of the liver that was successfully treated with placement of a transjugular intrahepatic porto-systemic stent-shunt (TIPS). Results: Therapy of variceal bleeding ...

  20. Nature of solar cyclicity. I

    Energy Technology Data Exchange (ETDEWEB)

    Romanchuk, P.R.

    1981-01-01

    The report contains a critical survey of work devoted to the study of the nature of solar cyclicity. The inconsistency of the representation of cyclic curves using a frequency spectrum is indicated. The useful contribution of the ideas of Wolf, Newcomb, and Waldmeier to the solution of the problem is noted. Data are cited in favor of the theory of the tidal nature of solar cyclicity developed by the author, which also takes into account the ideas of the above-mentioned authors: the continuous paired and single tidal actions of the planets and the resonance character of this action, thanks to which the approximately 10-year period of action of Jupiter and Saturn is transformed into the 11-year activity cycle.

  1. On Improvements of Cyclic MUSIC

    Directory of Open Access Journals (Sweden)

    H. Howard Fan

    2005-01-01

    Full Text Available Many man-made signals encountered in communications exhibit cyclostationarity. By exploiting cyclostationarity, cyclic MUSIC has been shown to be able to separate signals with different cycle frequencies, thus, to be able to perform signal selective direction of-arrival (DOA estimation. However, as will be shown in this paper, the DOA estimation of cyclic MUSIC is actually biased. We show in this paper that by properly choosing the frequency for evaluating the steering vector, the bias of DOA estimation can be substantially reduced and the performance can be improved. Furthermore, we propose another algorithm exploiting cyclic conjugate correlation to further improve the performance of DOA estimation. Simulation results show the effectiveness of both of our methods.

  2. Design of a cyclic multiverse

    Energy Technology Data Exchange (ETDEWEB)

    Piao Yunsong, E-mail: yspiao@gucas.ac.c [College of Physical Sciences, Graduate School of Chinese Academy of Sciences, Beijing 100049 (China)

    2010-08-09

    Recently, it has been noticed that the amplification of the amplitude of curvature perturbation cycle by cycle can lead to a cyclic multiverse scenario, in which the number of universes increases cycle by cycle. However, this amplification will also inevitably induce either the ultimate end of corresponding cycle, or the resulting spectrum of perturbations inside corresponding universe is not scale invariant, which baffles the existence of observable universes. In this Letter, we propose a design of a cyclic multiverse, in which the observable universe can emerges naturally. The significance of a long period of dark energy before the turnaround of each cycle for this implementing is shown.

  3. Deferasirox treatment improved hematopoiesis and led to complete remission in a patient with pure red cell aplasia.

    Science.gov (United States)

    Kojima, Minoru; Machida, Shinichiro; Sato, Ai; Miyamoto, Mitsuki; Moriuchi, Makiko; Ohbayashi, Yoshiaki; Ando, Kiyoshi

    2013-12-01

    A 64-year-old woman developed pure red cell aplasia (PRCA) 4 years after thymectomy for thymoma. During anti-thymocyte globulin treatment, the patient developed cytomegalovirus pneumonia and was thus unable to continue immunosuppressive therapy and became transfusion dependent. Deferasirox was started for treatment with iron overload when serum ferritin increased to >1000 ng/mL. Seven months after initiation of deferasirox treatment, serum ferritin level decreased the normal range and the patient has remained transfusion independent thereafter. Deferasirox was discontinued when serum ferritin level decreased below 500 ng/mL, and she has maintained in complete remission over the last 15 months. Hypotheses have been raised regarding the improvement of hematopoiesis by deferasirox treatment, but the mechanism whereby this might be achieved remains unclear. Deferasirox treatment may be clinically beneficial both by reducing iron overload and by improving hematopoiesis in patients with PRCA.

  4. Late stages of hematopoiesis and B cell lymphopoiesis are regulated by α-synuclein, a key player in Parkinson's disease.

    Science.gov (United States)

    Xiao, Wenbin; Shameli, Afshin; Harding, Clifford V; Meyerson, Howard J; Maitta, Robert W

    2014-11-01

    α-Synuclein plays a crucial role in Parkinson's disease and dementias defined as synucleinopathies. α-Synuclein is expressed in hematopoietic and immune cells, but its functions in hematopoiesis and immune responses are unknown. We utilized α-synuclein(-/-) (KO) mice to investigate its role in hematopoiesis and B cell lymphopoiesis. We demonstrated hematologic abnormalities including mild anemia, smaller platelets, lymphopenia but relatively normal early hematopoiesis in KO mice compared to wild-type (WT) as measured in hematopoietic stem cells and progenitors of the different cell lineages. However, the absolute number of B220(+)IgM(+) B cells in bone marrow was reduced by 4-fold in KO mice (WT: 104±23×10(5) vs. KO: 27±5×10(5)). B cells were also reduced in KO spleens associated with effacement of splenic and lymph node architecture. KO mice showed reduced total serum IgG but no abnormality in serum IgM was noted. When KO mice were challenged with a T cell-dependent antigen, production of antigen specific IgG1 and IgG2b was abolished, but antigen specific IgM was not different from WT mice. Our study shows hematologic abnormalities including anemia and smaller platelets, reduced B cell lymphopoiesis and defects in IgG production in the absence of α-synuclein. This is the first report to show an important role of α-synuclein late in hematopoiesis, B cell lymphopoiesis and adaptive immune response. Copyright © 2014 Elsevier GmbH. All rights reserved.

  5. Parallels between immune driven-hematopoiesis and T cell activation: 3 signals that relay inflammatory stress to the bone marrow

    Energy Technology Data Exchange (ETDEWEB)

    Libregts, Sten F.W.M.; Nolte, Martijn A., E-mail: m.nolte@sanquin.nl

    2014-12-10

    Quiescence, self-renewal, lineage commitment and differentiation of hematopoietic stem cells (HSCs) towards fully mature blood cells are a complex process that involves both intrinsic and extrinsic signals. During steady-state conditions, most hematopoietic signals are provided by various resident cells inside the bone marrow (BM), which establish the HSC micro-environment. However, upon infection, the hematopoietic process is also affected by pathogens and activated immune cells, which illustrates an effective feedback mechanism to hematopoietic stem and progenitor cells (HSPCs) via immune-mediated signals. Here, we review the impact of pathogen-associated molecular patterns (PAMPs), damage-associated molecular patterns (DAMPs), costimulatory molecules and pro-inflammatory cytokines on the quiescence, proliferation and differentiation of HSCs and more committed progenitors. As modulation of HSPC function via these immune-mediated signals holds an interesting parallel with the “three-signal-model” described for the activation and differentiation of naïve T-cells, we propose a novel “three-signal” concept for immune-driven hematopoiesis. In this model, the recognition of PAMPs and DAMPs will activate HSCs and induce proliferation, while costimulatory molecules and pro-inflammatory cytokines confer a second and third signal, respectively, which further regulate expansion, lineage commitment and differentiation of HSPCs. We review the impact of inflammatory stress on hematopoiesis along these three signals and we discuss whether they act independently from each other or that concurrence of these signals is important for an adequate response of HSPCs upon infection. - Highlights: • Inflammation and infection have a direct impact on hematopoiesis in the bone marrow. • We draw a striking parallel between immune-driven hematopoiesis and T cell activation. • We review how PAMPs and DAMPs, costimulation and cytokines influence HSPC function.

  6. Parallels between immune driven-hematopoiesis and T cell activation: 3 signals that relay inflammatory stress to the bone marrow

    International Nuclear Information System (INIS)

    Libregts, Sten F.W.M.; Nolte, Martijn A.

    2014-01-01

    Quiescence, self-renewal, lineage commitment and differentiation of hematopoietic stem cells (HSCs) towards fully mature blood cells are a complex process that involves both intrinsic and extrinsic signals. During steady-state conditions, most hematopoietic signals are provided by various resident cells inside the bone marrow (BM), which establish the HSC micro-environment. However, upon infection, the hematopoietic process is also affected by pathogens and activated immune cells, which illustrates an effective feedback mechanism to hematopoietic stem and progenitor cells (HSPCs) via immune-mediated signals. Here, we review the impact of pathogen-associated molecular patterns (PAMPs), damage-associated molecular patterns (DAMPs), costimulatory molecules and pro-inflammatory cytokines on the quiescence, proliferation and differentiation of HSCs and more committed progenitors. As modulation of HSPC function via these immune-mediated signals holds an interesting parallel with the “three-signal-model” described for the activation and differentiation of naïve T-cells, we propose a novel “three-signal” concept for immune-driven hematopoiesis. In this model, the recognition of PAMPs and DAMPs will activate HSCs and induce proliferation, while costimulatory molecules and pro-inflammatory cytokines confer a second and third signal, respectively, which further regulate expansion, lineage commitment and differentiation of HSPCs. We review the impact of inflammatory stress on hematopoiesis along these three signals and we discuss whether they act independently from each other or that concurrence of these signals is important for an adequate response of HSPCs upon infection. - Highlights: • Inflammation and infection have a direct impact on hematopoiesis in the bone marrow. • We draw a striking parallel between immune-driven hematopoiesis and T cell activation. • We review how PAMPs and DAMPs, costimulation and cytokines influence HSPC function

  7. The miR-23a~27a~24-2 microRNA cluster buffers transcription and signaling pathways during hematopoiesis.

    Science.gov (United States)

    Kurkewich, Jeffrey L; Hansen, Justin; Klopfenstein, Nathan; Zhang, Helen; Wood, Christian; Boucher, Austin; Hickman, Joseph; Muench, David E; Grimes, H Leighton; Dahl, Richard

    2017-07-01

    MicroRNA cluster mirn23a has previously been shown to promote myeloid development at the expense of lymphoid development in overexpression and knockout mouse models. This polarization is observed early in hematopoietic development, with an increase in common lymphoid progenitors (CLPs) and a decrease in all myeloid progenitor subsets in adult bone marrow. The pool size of multipotential progenitors (MPPs) is unchanged; however, in this report we observe by flow cytometry that polarized subsets of MPPs are changed in the absence of mirn23a. Additionally, in vitro culture of MPPs and sorted MPP transplants showed that these cells have decreased myeloid and increased lymphoid potential in vitro and in vivo. We investigated the mechanism by which mirn23a regulates hematopoietic differentiation and observed that mirn23a promotes myeloid development of hematopoietic progenitors through regulation of hematopoietic transcription factors and signaling pathways. Early transcription factors that direct the commitment of MPPs to CLPs (Ikzf1, Runx1, Satb1, Bach1 and Bach2) are increased in the absence of mirn23a miRNAs as well as factors that commit the CLP to the B cell lineage (FoxO1, Ebf1, and Pax5). Mirn23a appears to buffer transcription factor levels so that they do not stochastically reach a threshold level to direct differentiation. Intriguingly, mirn23a also inversely regulates the PI3 kinase (PI3K)/Akt and BMP/Smad signaling pathways. Pharmacological inhibitor studies, coupled with dominant active/dominant negative biochemical experiments, show that both signaling pathways are critical to mirn23a's regulation of hematopoietic differentiation. Lastly, consistent with mirn23a being a physiological inhibitor of B cell development, we observed that the essential B cell transcription factor EBF1 represses expression of mirn23a. In summary, our data demonstrates that mirn23a regulates a complex array of transcription and signaling pathways to modulate adult hematopoiesis.

  8. The miR-23a~27a~24-2 microRNA cluster buffers transcription and signaling pathways during hematopoiesis.

    Directory of Open Access Journals (Sweden)

    Jeffrey L Kurkewich

    2017-07-01

    Full Text Available MicroRNA cluster mirn23a has previously been shown to promote myeloid development at the expense of lymphoid development in overexpression and knockout mouse models. This polarization is observed early in hematopoietic development, with an increase in common lymphoid progenitors (CLPs and a decrease in all myeloid progenitor subsets in adult bone marrow. The pool size of multipotential progenitors (MPPs is unchanged; however, in this report we observe by flow cytometry that polarized subsets of MPPs are changed in the absence of mirn23a. Additionally, in vitro culture of MPPs and sorted MPP transplants showed that these cells have decreased myeloid and increased lymphoid potential in vitro and in vivo. We investigated the mechanism by which mirn23a regulates hematopoietic differentiation and observed that mirn23a promotes myeloid development of hematopoietic progenitors through regulation of hematopoietic transcription factors and signaling pathways. Early transcription factors that direct the commitment of MPPs to CLPs (Ikzf1, Runx1, Satb1, Bach1 and Bach2 are increased in the absence of mirn23a miRNAs as well as factors that commit the CLP to the B cell lineage (FoxO1, Ebf1, and Pax5. Mirn23a appears to buffer transcription factor levels so that they do not stochastically reach a threshold level to direct differentiation. Intriguingly, mirn23a also inversely regulates the PI3 kinase (PI3K/Akt and BMP/Smad signaling pathways. Pharmacological inhibitor studies, coupled with dominant active/dominant negative biochemical experiments, show that both signaling pathways are critical to mirn23a's regulation of hematopoietic differentiation. Lastly, consistent with mirn23a being a physiological inhibitor of B cell development, we observed that the essential B cell transcription factor EBF1 represses expression of mirn23a. In summary, our data demonstrates that mirn23a regulates a complex array of transcription and signaling pathways to modulate adult

  9. The Sirt1 activator SRT3025 expands hematopoietic stem and progenitor cells and improves hematopoiesis in Fanconi anemia mice

    Directory of Open Access Journals (Sweden)

    Qing-Shuo Zhang

    2015-07-01

    Full Text Available Fanconi anemia is a genetic bone marrow failure syndrome. The current treatment options are suboptimal and do not prevent the eventual onset of aplastic anemia requiring bone marrow transplantation. We previously showed that resveratrol, an antioxidant and an activator of the protein deacetylase Sirt1, enhanced hematopoiesis in Fancd2 mutant mice and improved the impaired stem cell quiescence observed in this disease. Given that Sirt1 is important for the function of hematopoietic stem cells, we hypothesized that Sirt1 activation may improve hematopoiesis. Indeed, Fancd2−/− mice and wild-type mice treated with the selective Sirt1 activator SRT3025 had increased numbers of hematopoietic stem and progenitor cells, platelets and white blood cells. SRT3025 was also protective against acetaldehyde-induced hematopoietic damage. Unlike resveratrol, however, SRT3025 did not affect stem cell quiescence, suggesting distinct mechanisms of action. Conditional deletion of Sirt1 in hematopoietic cells did not abrogate the beneficial effects of SRT3025, indicating that the drug did not act by directly stimulating Sirt1 in stem cells, but must be acting indirectly via extra-hematopoietic effects. RNA-Seq transcriptome analysis revealed the down-regulation of Egr1–p21 expression, providing a potential mechanism for improved hematopoiesis. Overall, our data indicate that SRT3025 or related compounds may be beneficial in Fanconi anemia and other bone marrow failure syndromes.

  10. Expression profile analysis of aorta-gonad-mesonephros region-derived stromal cells reveals genes that regulate hematopoiesis

    International Nuclear Information System (INIS)

    Nagao, Kenji; Ohta, Takayuki; Hinohara, Atsushi; Tahara, Tomoyuki; Hagiwara, Tetsuya; Maeda, Yoshitake; Yoneya, Takashi; Sohma, Yoshiaki; Heike, Toshio; Nakahata, Tatsutoshi; Inagaki, Yoshimasa; Nishikawa, Mitsuo

    2008-01-01

    The aorta-gonad-mesonephros (AGM) region is involved in the generation and maintenance of the first definitive hematopoietic stem cells (HSCs). A mouse AGM-derived cell line, AGM-S3, was shown to support the development of HSCs. To elucidate the molecular mechanisms regulating early hematopoiesis, we obtained subclones from AGM-S3, one of which was hematopoiesis supportive (S3-A9) and the other one of which was non-supportive (S3-A7), and we analyzed their gene expression profiles by gene chip analysis. In the present study, we found that Glypican-1 (GPC1) was highly expressed in the supportive subclone AGM-S3-A9. Over-expression of GPC1 in non-supportive cells led to the proliferation of progenitor cells in human cord blood when cocultured with the transfected-stromal cells. Thus, GPC1 may have an important role in the establishment of a microenvironment that supports early events in hematopoiesis

  11. Cyclic Processing for Context Fusion

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun

    2007-01-01

    Many machine-learning techniques use feedback information. However, current context fusion systems do not support this because they constrain processing to be structured as acyclic processing. This paper proposes a generalization which enables the use of cyclic processing in context fusion systems...

  12. Cyclic codes of length 2

    Indian Academy of Sciences (India)

    Springer Verlag Heidelberg #4 2048 1996 Dec 15 10:16:45

    [X]/〈X2m. − 1〉 are given. Cyclic codes of length 2m over the finite field Fq, of odd characteristic, are defined in terms of their generator polynomials. The exact minimum distance and the dimension of the codes are obtained. Keywords.

  13. Color visualization of cyclic magnitudes

    Science.gov (United States)

    Restrepo, Alfredo; Estupiñán, Viviana

    2014-02-01

    We exploit the perceptual, circular ordering of the hues in a technique for the visualization of cyclic variables. The hue is thus meaningfully used for the indication of variables such as the azimuth and the units of the measurement of time. The cyclic (or circular) variables may be both of the continuous type or the discrete type; among the first there is azimuth and among the last you find the musical notes and the days of the week. A correspondence between the values of a cyclic variable and the chromatic hues, where the natural circular ordering of the variable is respected, is called a color code for the variable. We base such a choice of hues on an assignment of of the unique hues red, yellow, green and blue, or one of the 8 even permutations of this ordered list, to 4 cardinal values of the cyclic variable, suitably ordered; color codes based on only 3 cardinal points are also possible. Color codes, being intuitive, are easy to remember. A possible low accuracy when reading instruments that use this technique is compensated by fast, ludic and intuitive readings; also, the use of a referential frame makes readings precise. An achromatic version of the technique, that can be used by dichromatic people, is proposed.

  14. Cyclic theory of Lie algebroids

    NARCIS (Netherlands)

    Blom, A.

    2017-01-01

    In this thesis we study the cyclic theory of universal enveloping algebras of Lie algebroids. Lie algebroids are geometrical objects that encode infinitesimal symmetries, and the concept encompasses many classical objects from geometry, such as Poisson manifolds, foliations and actions of Lie

  15. SELENIUM EFFECT UPON THE RATS' HEMATOPOIESIS IN THE SUBACUTE BENZENE INTOXICATION

    Directory of Open Access Journals (Sweden)

    Pavle Randjelovic

    2001-03-01

    Full Text Available The antioxidants (selenium, vitamins C and E stabilize the cell membrane andprotect the cells from the action of free radicals. On the other hand, the antioxidantsreduce the effects of chemical and physical agenls. Bcsidcs, selenium has animportant role in Transporting electrons in the mitochondria and il is necessary for iheglulathione peroxidase function in the protection from apoplhosis. Benzene is auniversal solvent and has a wide application in chemical industry. Its toxicity ismanifested in the damages done to the central nervous syslem, liver, kidneys andhematopoiesis system. Tn this experiment the Wistar rats were used that wereclassified in three experimental groups regarding the quantity of the receivedselenium. Each group comprised ten animals of both sexes and after two weeks'treatment by selenium of 4,8 and 16 mcg, the animals had received benzene byinlraperiloneal administration in the dose of 1,2 ml/kg of the body weight. Thecounting of the shaped blood elements was done after the selenium pretreatment andafter the benzene intoxication. The obtained results poinl to increased number of alithe blood elements after the selenium pretreatment while after benzene adminislrationthere was a drastic drop of the number of erylhrocyles and leukocytes alongwith moderate lhrombocylopenia. After the sacrifice, Ihe hematopoiesis organs weretaken. The hislological findings of the bone marrow show the emergence ofdisturbances, especially of the red sort cells as well as an obvious fat degeneration which is particularly conspicuous in the second and third groups of animals. Therewas also some damage done to the spleen, especially of its red pulp along with thepresence of a greater number of fresh erythrocytes in the second and third groups.Only the changes were more drastic in the third group. The obtained results show thatselenium in higher concentrations increases the number of erytrocytes andleukocytes which proves that it stimulates highly

  16. Cyclic peptide therapeutics: past, present and future.

    Science.gov (United States)

    Zorzi, Alessandro; Deyle, Kaycie; Heinis, Christian

    2017-06-01

    Cyclic peptides combine several favorable properties such as good binding affinity, target selectivity and low toxicity that make them an attractive modality for the development of therapeutics. Over 40 cyclic peptide drugs are currently in clinical use and around one new cyclic peptide drug enters the market every year on average. The vast majority of clinically approved cyclic peptides are derived from natural products, such as antimicrobials or human peptide hormones. New powerful techniques based on rational design and in vitro evolution have enabled the de novo development of cyclic peptide ligands to targets for which nature does not offer solutions. A look at the cyclic peptides currently under clinical evaluation shows that several have been developed using such techniques. This new source for cyclic peptide ligands introduces a freshness to the field, and it is likely that de novo developed cyclic peptides will be in clinical use in the near future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Deformation mechanisms in cyclic creep and fatigue

    International Nuclear Information System (INIS)

    Laird, C.

    1979-01-01

    Service conditions in which static and cyclic loading occur in conjunction are numerous. It is argued that an understanding of cyclic creep and cyclic deformation are necessary both for design and for understanding creep-fatigue fracture. Accordingly a brief, and selective, review of cyclic creep and cyclic deformation at both low and high strain amplitudes is provided. Cyclic loading in conjunction with static loading can lead to creep retardation if cyclic hardening occurs, or creep acceleration if softening occurs. Low strain amplitude cyclic deformation is understood in terms of dislocation loop patch and persistent slip band behavior, high strain deformation in terms of dislocation cell-shuttling models. While interesting advances in these fields have been made in the last few years, the deformation mechanisms are generally poorly understood

  18. Spinal cord compression due to extramedullary hematopoiesis in beta-thalassemia intermedia

    International Nuclear Information System (INIS)

    Munn, Rita K.; Kramer, Carol A.; Arnold, Susanne M.

    1998-01-01

    Background: Extramedullary hematopoiesis (EMH) occurs in many disorders, including thalassemias and other hemoglobinopathies, and commonly presents in the spleen and liver. We present a case of spinal cord compression in a patient with beta-thalassemia intermedia, and review the literature and available treatment options. Patient and Methods: A 35-year-old black female with beta-thalassemia intermedia presented with a 3-week history of back pain and lower extremity weakness. Neurologic examination was consistent with spinal cord compression, and gadolinium enhanced magnetic resonance imaging (MRI) confirmed this diagnosis. She was given intravenous steroids and radiotherapy was begun in 200 cGy fractions to a total dose of 2000 cGy. Results: At the completion of radiotherapy the patient was ambulatory with mild residual weakness. MRI scans 16 months later showed smaller, but persistent masses, and she remains asymptomatic 5 years from her diagnosis. Conclusion: Recognition of spinal cord EMH requires prompt physical examination and MRI for accurate diagnosis. EMH can be managed with radiation, surgery, transfusions, or a combination of these therapies. Radiation in conservative doses of (750-3500 cGy) is non-invasive, avoids the surgical risks of potentially severe hemorrhage and incomplete resection, and has a high complete remission rate in the majority of patients. Relapse rates are moderate (37.5%), but retreatment provides excellent chance for second remission

  19. Effect of spaceflight on human stem cell hematopoiesis: suppression of erythropoiesis and myelopoiesis.

    Science.gov (United States)

    Davis, T A; Wiesmann, W; Kidwell, W; Cannon, T; Kerns, L; Serke, C; Delaplaine, T; Pranger, A; Lee, K P

    1996-07-01

    Humans subjected to periods of microgravity develop anemia, thrombocytopenia, and abnormalities in red blood cell structure. The causes of these abnormalities are complex and unclear. The in vitro effects of spaceflight on hematopoietic cell proliferation and differentiation were investigated during the space shuttle missions STS-63 (Discovery) and STS-69 (Endeavour). CD34+ bone marrow progenitor cells were cultured in liquid suspension culture and on hematopoietic supportive stromal cells using hollow-fiber culture modules. One set of cultures was maintained at microgravity (flight cultures) for the last 8-10 days of culture and a second control was at full gravity (ground control). Over the 11- to 13-test-day period, ground control culture total cell number increased 41.0- to 65.5-fold but flight culture total cell number increased only 10.1- to 17.6-fold (57-84% decrease). Comparing ground control cultures and microgravity cultures, respectively, for progenitor cell content, myeloid progenitor cell numbers expanded 2.6- to 17.5-fold compared with 0.9- to 7.0-fold and erythroid progenitor cell numbers expanded 2.0- to 4.1-fold in ground control cultures but actually declined at microgravity (>83% reduction). Moreover, microgravity cultures demonstrated accelerated maturation/differentiation toward the macrophage lineage. These data indicate that spaceflight has a direct effect on hematopoietic progenitor cell proliferation and differentiation and that specific aspects of in vitro hematopoiesis, particularly erythropoiesis, involve gravity-sensitive components.

  20. GATA4-dependent organ-specific endothelial differentiation controls liver development and embryonic hematopoiesis.

    Science.gov (United States)

    Géraud, Cyrill; Koch, Philipp-Sebastian; Zierow, Johanna; Klapproth, Kay; Busch, Katrin; Olsavszky, Victor; Leibing, Thomas; Demory, Alexandra; Ulbrich, Friederike; Diett, Miriam; Singh, Sandhya; Sticht, Carsten; Breitkopf-Heinlein, Katja; Richter, Karsten; Karppinen, Sanna-Maria; Pihlajaniemi, Taina; Arnold, Bernd; Rodewald, Hans-Reimer; Augustin, Hellmut G; Schledzewski, Kai; Goerdt, Sergij

    2017-03-01

    Microvascular endothelial cells (ECs) are increasingly recognized as organ-specific gatekeepers of their microenvironment. Microvascular ECs instruct neighboring cells in their organ-specific vascular niches through angiocrine factors, which include secreted growth factors (angiokines), extracellular matrix molecules, and transmembrane proteins. However, the molecular regulators that drive organ-specific microvascular transcriptional programs and thereby regulate angiodiversity are largely elusive. In contrast to other ECs, which form a continuous cell layer, liver sinusoidal ECs (LSECs) constitute discontinuous, permeable microvessels. Here, we have shown that the transcription factor GATA4 controls murine LSEC specification and function. LSEC-restricted deletion of Gata4 caused transformation of discontinuous liver sinusoids into continuous capillaries. Capillarization was characterized by ectopic basement membrane deposition, formation of a continuous EC layer, and increased expression of VE-cadherin. Correspondingly, ectopic expression of GATA4 in cultured continuous ECs mediated the downregulation of continuous EC-associated transcripts and upregulation of LSEC-associated genes. The switch from discontinuous LSECs to continuous ECs during embryogenesis caused liver hypoplasia, fibrosis, and impaired colonization by hematopoietic progenitor cells, resulting in anemia and embryonic lethality. Thus, GATA4 acts as master regulator of hepatic microvascular specification and acquisition of organ-specific vascular competence, which are indispensable for liver development. The data also establish an essential role of the hepatic microvasculature in embryonic hematopoiesis.

  1. Dietary glutamine supplementation affects macrophage function, hematopoiesis and nutritional status in early weaned mice.

    Science.gov (United States)

    Rogero, Marcelo Macedo; Borelli, Primavera; Vinolo, Marco Aurélio Ramirez; Fock, Ricardo Ambrósio; de Oliveira Pires, Ivanir Santana; Tirapegui, Julio

    2008-06-01

    To investigate the effect that early weaning associated with the ingestion of either a glutamine-free or supplemented diet has on the functioning of peritoneal macrophages, hematopoiesis and nutritional status of mice. Swiss Webster mice were early weaned on their 14th day of life and distributed to two groups, being fed either a glutamine-free diet (-GLN) or a glutamine-supplemented diet (+GLN). Animals belonging to a control group (CON) were weaned on their 21st day of life. The -GLN and +GLN groups had a lower lean body mass, carcass protein and ash content, plasma glutamine concentration and lymphocyte counts both in the peripheral blood and bone marrow when compared to the CON group (Psupplementation with glutamine reversed both the lower concentrations of protein and DNA in the muscle and liver, as well as the reduced capacity of spreading and synthesizing nitric oxide, hydrogen peroxide, TNF-alpha, IL-1 beta and IL-6 in cultures of peritoneal macrophages obtained from the -GLN group (Psupplemented diet cannot substitute maternal milk in respect to immunological and metabolic parameters.

  2. Cis-element mutated in GATA2-dependent immunodeficiency governs hematopoiesis and vascular integrity

    Science.gov (United States)

    Johnson, Kirby D.; Hsu, Amy P.; Ryu, Myung-Jeom; Wang, Jinyong; Gao, Xin; Boyer, Meghan E.; Liu, Yangang; Lee, Youngsook; Calvo, Katherine R.; Keles, Sunduz; Zhang, Jing; Holland, Steven M.; Bresnick, Emery H.

    2012-01-01

    Haploinsufficiency for GATA2 causes human immunodeficiency syndromes characterized by mycobacterial infection, myelodysplasia, lymphedema, or aplastic anemia that progress to myeloid leukemia. GATA2 encodes a master regulator of hematopoiesis that is also linked to endothelial biology. Though the disease-causing mutations commonly occur in the GATA-2 DNA binding domain, we identified a patient with mycobacterial infection and myelodysplasia who had an uncharacterized heterozygous deletion in a GATA2 cis-element consisting of an E-box and a GATA motif. Targeted deletion of the equivalent murine element to yield homozygous mutant mice revealed embryonic lethality later than occurred with global Gata2 knockout, hematopoietic stem/progenitor cell depletion, and impaired vascular integrity. Heterozygous mutant mice were viable, but embryos exhibited deficits in definitive, but not primitive, hematopoietic stem/progenitor activity and reduced expression of Gata2 and its target genes. Mechanistic analysis revealed disruption of the endothelial cell transcriptome and loss of vascular integrity. Thus, the composite element disrupted in a human immunodeficiency is essential for establishment of the murine hematopoietic stem/progenitor cell compartment in the fetal liver and for essential vascular processes. PMID:22996659

  3. Regulation of embryonic hematopoiesis by a cytokine-inducible SH2 domain homolog in zebrafish.

    Science.gov (United States)

    Lewis, Rowena S; Noor, Suzita M; Fraser, Fiona W; Sertori, Robert; Liongue, Clifford; Ward, Alister C

    2014-06-15

    Cytokine-inducible SH2 domain-containing protein (CISH), a member of the suppressor of cytokine signaling family of negative feedback regulators, is induced by cytokines that activate STAT5 and can inhibit STAT5 signaling in vitro. However, demonstration of a definitive in vivo role for CISH during development has remained elusive. This study employed expression analysis and morpholino-mediated knockdown in zebrafish in concert with bioinformatics and biochemical approaches to investigate CISH function. Two zebrafish CISH paralogs were identified, cish.a and cish.b, with high overall conservation (43-46% identity) with their mammalian counterparts. The cish.a gene was maternally derived, with transcripts present throughout embryogenesis, and increasing at 4-5 d after fertilization, whereas cish.b expression commenced at 8 h after fertilization. Expression of cish.a was regulated by the JAK2/STAT5 pathway via conserved tetrameric STAT5 binding sites (TTCN3GAA) in its promoter. Injection of morpholinos targeting cish.a, but not cish.b or control morpholinos, resulted in enhanced embryonic erythropoiesis, myelopoiesis, and lymphopoiesis, including a 2- 3-fold increase in erythrocytic markers. This occurred concomitantly with increased activation of STAT5. This study indicates that CISH functions as a conserved in vivo target and regulator of STAT5 in the control of embryonic hematopoiesis. Copyright © 2014 by The American Association of Immunologists, Inc.

  4. Role of the spleen in cyclophosphamide-induced hematosuppression and extramedullary hematopoiesis in mice.

    Science.gov (United States)

    Wang, Yuli; Meng, Qinggang; Qiao, Haiquan; Jiang, Hongchi; Sun, Xueying

    2009-05-01

    Extramedullary hematopoiesis (EMH) is induced in spleens due to various diseases. The aim of this study is to investigate the role of spleen in cyclophosphamide (CTX)-induced hematosuppression and EMH in mice. Balb/c mice were IP injected with 300 mg/kg CTX 2 weeks after splenectomy or sham operation and randomly sacrificed 1, 3, 7, 14, and 21 days after injection. Blood samples were collected, and spleens were weighed, histologically analyzed, and then used for flow cytometry. There were significant differences in white blood count, red blood count, platelet numbers and hemoglobin concentration between the splenectomized and sham-operated mice after CTX injection. The cellularity of the spleen was reduced 3 days following CTX treatment but then rose 7 days after CTX treatment. The numbers of colony-forming units in the spleen reached a peak 7 days after CTX injection, then declined. Flow cytometry demonstrated the percentage of CD34(+) and CD117(+) cells in the spleen increased 7 days after CTX injection, indicating the hematopoietic stem and progenitor cells in the spleen. The study indicates that EMH occurs as a compensatory reaction to CTX-induced hematosuppression in the murine spleen, implying that conservation of the spleen may promote the recovery of cancer patients from chemotherapy-induced hematosuppression.

  5. Extramedullary hematopoiesis of the liver in a child with sickle cell disease: A rare complication.

    Science.gov (United States)

    Barrier, Angela; Willy, Simo; Slone, Jeremy S

    2015-08-01

    We present the case of a 7-year-old Cameroonian girl with sickle cell disease (SCD) who presented with progressive abdominal distension, fever, severe anemia, respiratory distress, and fatigue. Abdominal ultrasound showed a 15.3 cm × 11.5 cm × 15.5 cm solid echogenic mass within the left lobe of the liver. Fine-needle aspiration showed features of extramedullary hematopoiesis (EMH). Despite transfusions, antibiotics, and initiation of hydroxyurea the patient died of respiratory failure during the hospital stay. There is a paucity of information on EMH in the pediatric sickle cell population, especially from resource-limited settings such as western Africa. EMH, however, is a known complication of SCD and should be considered in patients presenting with mass lesions in the setting of chronic anemia. With limited therapeutic interventions for EMH, including radiation and hydroxyurea, the emphasis should be on improving overall treatment of patients with chronic and untreated hemolytic anemia, especially in low-income countries. © 2015 Japan Pediatric Society.

  6. Intracranial extramedullary hematopoiesis in patients with thalassemia: a case report and review of the literature.

    Science.gov (United States)

    Eskazan, Ahmet Emre; Ar, Muhlis Cem; Baslar, Zafer

    2012-08-01

    Extramedullary hematopoiesis (EH) is a compensatory phenomenon that results in the production of blood cell precursors outside the marrow in patients with chronic hemolytic anemia and ineffective erythropoiesis. EH usually involves the liver, spleen, and lymph nodes. It can also be found at paravertebral, intrathoracic, or pelvic locations. Intracranial EH is a rare entity and often asymptomatic but can sometimes lead to symptomatic tumor-like masses. Treatment options are controversial and include hypertransfusion, surgical excision, radiotherapy, and hydroxyurea (HU). Successful treatment of an intracranial EH mass with HU and blood transfusions in a beta-thalassemia major patient was discussed along with a review of the published literature on intracranial EH in thalassemia. In our patient, the extramedullary hematopoietic mass in the interhemispheric fissure showed a marked improvement after 6 months of HU and hypertransfusion therapy. In the English literature, there are a few cases with intracranial EH and thalassemia, which were treated with different treatment modalities, with different outcomes. There is no standard treatment approach in patients with symptomatic EH. HU with hypertransfusion regimen is a reasonable first-choice modality in treating intracranial EH masses. © 2012 American Association of Blood Banks.

  7. Chronic Idiopathic Myelofibrosis Presenting as Cauda Equina Compression due to Extramedullary Hematopoiesis: A Case Report

    Science.gov (United States)

    Goh, Duck-Ho; Cho, Dae-Chul; Park, Seong-Hyun; Hwang, Jeong-Hyun; Sung, Joo-Kyung

    2007-01-01

    Extramedullary hematopoiesis (EMH) is occasionally reported in idiopathic myelofibrosis and is generally found in the liver, spleen, and lymph nodes several years after diagnosis. Myelofibrosis presenting as spinal cord compression, resulting from EMH tissue is very rare. A 39-yr-old man presented with back pain, subjective weakness and numbness in both legs. Sagittal magnetic resonance imaging showed multiple anterior epidural mass extending from L4 to S1 with compression of cauda equina and nerve root. The patient underwent gross total removal of the mass via L4, 5, and S1 laminectomy. Histological analysis showed islands of myelopoietic cells surrounded by fatty tissue, consistent with EMH, and bone marrow biopsy performed after surgery revealed hypercellular marrow and megakaryocytic hyperplasia and focal fibrosis. The final diagnosis was chronic idiopathic myelofibrosis leading to EMH in the lumbar spinal canal. Since there were no abnormal hematological findings except mild myelofibrosis, additional treatment such as radiothepary was not administered postoperatively for fear of radiotoxicity. On 6 month follow-up examination, the patient remained clinically stable without recurrence. This is the first case of chronic idiopathic myelofibrosis due to EMH tissue in the lumbar spinal canal in Korea. PMID:18162730

  8. Extramedullary hematopoiesis (EMH) in laboratory animals: offering an insight into stem cell research.

    Science.gov (United States)

    Chiu, Shao-Chih; Liu, Hua-Hsing; Chen, Chia-Ling; Chen, Pin-Ru; Liu, Ming-Chao; Lin, Shinn-Zong; Chang, Ko-Tung

    2015-01-01

    Extramedullary hematopoiesis (EMH) is a pathological process secondary to underlying bone marrow (BM) insufficiency in adults. It is characterized by the emergence of multipotent hematopoietic progenitors scattered around the affected tissue, most likely in the spleen, liver, and lymph node, etc. EMH in patients frequently receives less medical attention and is neglected unless a compressive or obstructive hematopoietic mass appears to endanger the patient's life. However, on a biological basis, EMH reflects the alteration of relationships among hematopoietic stem and progenitor cells (HSPCs) and their original and new microenvironments. The ability of hematopoietic stem cells (HSCs) to mobilize from the bone marrow and to accommodate and function in extramedullary tissues is rather complicated and far from our current understanding. Fortunately, many reports from the studies of drugs and genetics using animals have incidentally found EMH to be involved. Thereby, the molecular basis of EMH could further be elucidated from those animals after cross-comparison. A deeper understanding of the extramedullary hematopoietic niche could help expand stem cells in vitro and establish a better treatment in patients for stem cell transplantation.

  9. The protumorigenic potential of FTY720 by promoting extramedullary hematopoiesis and MDSC accumulation.

    Science.gov (United States)

    Li, Y; Zhou, T; Wang, Y; Ning, C; Lv, Z; Han, G; Morris, J C; Taylor, E N; Wang, R; Xiao, H; Hou, C; Ma, Y; Shen, B; Feng, J; Guo, R; Li, Y; Chen, G

    2017-06-29

    FTY720 (also called fingolimod) is recognized as an immunosuppressant and has been approved by the Food and Drug Administration to treat refractory multiple sclerosis. However, long-term administration of FTY720 potentially increases the risk for cancer in recipients. The underlying mechanisms remain poorly understood. Herein, we provided evidence that FTY720 administration potentiated tumor growth. Mechanistically, FTY720 enhanced extramedullary hematopoiesis and massive accumulation of myeloid-derived suppressor cells (MDSCs), which actively suppressed antitumor immune responses. Granulocyte-macrophage colony-stimulating factor (GM-CSF), mainly produced by MDSCs, was identified as a key factor to mediate these effects of FTY720 in tumor microenvironment. Furthermore, we showed that FTY720 triggers MDSCs to release GM-CSF via S1P receptor 3 (S1pr3) through Rho kinase and extracellular signal-regulated kinase-dependent pathway. Thus, our findings provide mechanistic explanation for the protumorigenic potentials of FTY720 and suggest that targeting S1pr3 simultaneously may be beneficial for the patients receiving FTY720 treatment.

  10. Itga2b regulation at the onset of definitive hematopoiesis and commitment to differentiation.

    Directory of Open Access Journals (Sweden)

    Stephanie Dumon

    Full Text Available Product of the Itga2b gene, CD41 contributes to hematopoietic stem cell (HSC and megakaryocyte/platelet functions. CD41 expression marks the onset of definitive hematopoiesis in the embryo where it participates in regulating the numbers of multipotential progenitors. Key to platelet aggregation, CD41 expression also characterises their precursor, the megakaryocyte, and is specifically up regulated during megakaryopoiesis. Though phenotypically unique, megakaryocytes and HSC share numerous features, including key transcription factors, which could indicate common sub-regulatory networks. In these respects, Itga2b can serve as a paradigm to study features of both developmental-stage and HSC- versus megakaryocyte-specific regulations. By comparing different cellular contexts, we highlight a mechanism by which internal promoters participate in Itga2b regulation. A developmental process connects epigenetic regulation and promoter switching leading to CD41 expression in HSC. Interestingly, a similar process can be observed at the Mpl locus, which codes for another receptor that defines both HSC and megakaryocyte identities. Our study shows that Itga2b expression is controlled by lineage-specific networks and associates with H4K8ac in megakaryocyte or H3K27me3 in the multipotential hematopoietic cell line HPC7. Correlating with the decrease in H3K27me3 at the Itga2b Iocus, we find that following commitment to megakaryocyte differentiation, the H3K27 demethylase Jmjd3 up-regulation influences both Itga2b and Mpl expression.

  11. Monopod bucket foundations under cyclic lateral loading

    DEFF Research Database (Denmark)

    Foglia, Aligi; Ibsen, Lars Bo

    on bucket foundations under lateral cyclic loading. The test setup is described in detail and a comprehensive experimental campaign is presented. The foundation is subjected to cyclic overturning moment, cyclic horizontal loading and constant vertical loading, acting on the same plane for thousands...

  12. Cyclic homology and group actions

    Science.gov (United States)

    Ponge, Raphaël

    2018-01-01

    In this paper we present the construction of explicit quasi-isomorphisms that compute the cyclic homology and periodic cyclic homology of crossed-product algebras associated with (discrete) group actions. In the first part we deal with algebraic crossed-products associated with group actions on unital algebras over any ring k ⊃ Q. In the second part, we extend the results to actions on locally convex algebras. We then deal with crossed-products associated with group actions on manifolds and smooth varieties. For the finite order components, the results are expressed in terms of what we call "mixed equivariant cohomology". This "mixed" theory mediates between group homology and de Rham cohomology. It is naturally related to equivariant cohomology, and so we obtain explicit constructions of cyclic cycles out of equivariant characteristic classes. For the infinite order components, we simplify and correct the misidentification of Crainic (1999). An important new homological tool is the notion of "triangular S-module". This is a natural generalization of the cylindrical complexes of Getzler-Jones. It combines the mixed complexes of Burghelea-Kassel and parachain complexes of Getzler-Jones with the S-modules of Kassel-Jones. There are spectral sequences naturally associated with triangular S-modules. In particular, this allows us to recover spectral sequences of Feigin-Tsygan and Getzler-Jones and leads us to a new spectral sequence.

  13. Hematopoiese extramedular intratorácica: relato de um caso Intrathoracic extramedullary hematopoiesis: a case report

    Directory of Open Access Journals (Sweden)

    Luiza Beatriz Melo Moreira

    2001-06-01

    Full Text Available Os autores relatam o caso de um paciente do sexo masculino, de 40 anos de idade, portador de anemia falciforme, que desenvolveu a forma intratorácica de hematopoiese extramedular, apresentando lesões expansivas com densidade de partes moles, localizadas posteriormente, nas goteiras paravertebrais, na radiologia convencional. A tomografia computadorizada do tórax demonstrou massas bem delimitadas, de contornos lobulados, com densidade heterogênea à custa de áreas de tecido gorduroso e de densidade de partes moles, localizadas no terço inferior das goteiras paravertebrais. Os pulmões tinham coeficientes de atenuação preservados. A tomografia computadorizada de abdome revelou importante aumento da densidade e do volume do fígado, atribuídos à hemossiderose, e baço atrófico e calcificado devido a infartos esplênicos de repetição.The authors report a case of a 40-year-old male patient with sickle cell disease who presented with intra-thoracic extramedullary hematopoiesis and paravertebral expansive lesions that appeared as soft tissue density masses on conventional x-ray films. A computed tomography of the chest demonstrated soft tissue density masses in the lower third of the paravertebral spaces. These masses presented well-defined limits, lobulated edges and were heterogeneous due to areas of interposed adipose and soft density tissues. The lung parenchyma had no abnormalities. Computed tomography of the abdomen revealed diffuse hiperdensity and enlargement of the liver that was attributed to hemosiderosis, and an atrophic and calcified spleen due to repeated episodes of infarction.

  14. MDS-associated somatic mutations and clonal hematopoiesis are common in idiopathic cytopenias of undetermined significance.

    Science.gov (United States)

    Kwok, Brian; Hall, Jeff M; Witte, John S; Xu, Yin; Reddy, Prashanti; Lin, Keming; Flamholz, Rachel; Dabbas, Bashar; Yung, Aine; Al-Hafidh, Jenan; Balmert, Emily; Vaupel, Christine; El Hader, Carlos; McGinniss, Matthew J; Nahas, Shareef A; Kines, Julie; Bejar, Rafael

    2015-11-19

    Establishing a diagnosis in patients suspected of having a myelodysplastic syndrome (MDS) can be challenging and could be informed by the identification of somatic mutations. We performed a prospective study to examine the frequency and types of mutations encountered in 144 patients with unexplained cytopenias. Based on bone marrow findings, 17% were diagnosed with MDS, 15% with idiopathic cytopenias of undetermined significance (ICUS) and some evidence of dysplasia, and 69% with ICUS and no dysplasia. Bone marrow DNA was sequenced for mutations in 22 frequently mutated myeloid malignancy genes. Somatic mutations were identified in 71% of MDS patients, 62% of patients with ICUS and some dysplasia, and 20% of ICUS patients and no dysplasia. In total, 35% of ICUS patients carried a somatic mutation or chromosomal abnormality indicative of clonal hematopoiesis. We validated these results in a cohort of 91 lower-risk MDS and 249 ICUS cases identified over a 6-month interval. Mutations were found in 79% of those with MDS, in 45% of those with ICUS with dysplasia, and in 17% of those with ICUS without dysplasia. The spectrum of mutated genes was similar with the exception of SF3B1 which was rarely mutated in patients without dysplasia. Variant allele fractions were comparable between clonal ICUS (CCUS) and MDS as were mean age and blood counts. We demonstrate that CCUS is a more frequent diagnosis than MDS in cytopenic patients. Clinical and mutational features are similar in these groups and may have diagnostic utility once outcomes in CCUS patients are better understood. © 2015 by The American Society of Hematology.

  15. Nephrotic syndrome in primary myelofibrosis with renal extramedullary hematopoiesis and glomerulopathy in the JAK inhibitor era.

    Science.gov (United States)

    Del Sordo, Rachele; Brugnano, Rachele; Covarelli, Carla; Fiorucci, Gioia; Falzetti, Franca; Barbatelli, Giorgio; Nunzi, Emidio; Sidoni, Angelo

    2017-01-01

    Primary myelofibrosis (PMF) is an uncommon form of myeloproliferative neoplasm (MPN) characterized by a proliferation of predominantly megakaryocytes and granulocytes in the bone marrow that, in fully-developed disease, is associated with reactive deposition of fibrous connective tissue, extramedullary hematopoiesis (EMH), and splenomegaly. Kidney involvement is rare and clinically presents with proteinuria, nephrotic syndrome, and renal insufficiency. Renal damage can be due to EMH and glomerulopathy. Renal EMH presents three patterns: infiltration of the interstitium with possible renal failure caused by functional damage of parenchyma and vessels, infiltration of capsule and pericapsular adipose tissue, and sclerosing mass-like lesions that can cause hydronephrosis and hydroureter with obstructive uropathy and renal failure. Glomerulopathy associated with PMF is rarely described, ranging from 1 month to 18 years from diagnosis of the neoplasm to renal biopsy. It is characterized by expansion and hypercellularity mesangial, segmental sclerosis, features of chronic thrombotic microangiopathy (TMA), and intracapillary hematopoietic cells infiltrating in absence of immune-mediated glomerulonephritis. We present a nephrotic syndrome in PMF-related glomerulopathy, associated with EMH, without renal failure, in a patient under treatment for 2 years with JAK2 inhibitor ruxolitinib. Despite treatment, the patient died 7 months after renal biopsy. Nephrologists still know very little about this topic and there is no homogeneous data about incidence, pathogenesis, and optimal treatment of this poor prognostic PMF-associated nephrotic syndrome. We focus on data in the literature in the hope of stimulating hematologists, nephrologists, pathologists to future studies about the natural history of renal involvement, useful for optimal management of this rare pathology.

  16. Transjugular intrahepatic porto-systemic stent-shunt for therapy of bleeding esophageal varices due to extramedullary hematopoiesis in primary myelofibrosis: a case report.

    Science.gov (United States)

    Phillip, Veit; Berger, Hermann; Straub, Melanie; Saugel, Bernd; Treiber, Matthias; Einwächter, Henrik; Schmid, Roland M; Huber, Wolfgang

    2012-01-01

    Primary myelofibrosis belongs to the group of myeloproliferative syndromes. Extramedullary hematopoiesis in the liver can lead to portal hypertension. We report a case of a patient with life-threatening, endoscopically not treatable bleeding from esophageal varices due to extramedullary hematopoiesis of the liver that was successfully treated with placement of a transjugular intrahepatic porto-systemic stent-shunt (TIPS). Therapy of variceal bleeding by TIPS insertion was successful. During a 29-month follow-up, no hepatic failure, hepatic encephalopathy, or further variceal bleeding episode occurred. TIPS placement is a well-established procedure for the treatment of complications due to portal hypertension mainly due to liver cirrhosis. This report illustrates that TIPS placement can also be a promising treatment option in patients with primary myelofibrosis and portal hypertension due to extramedullary hematopoiesis. Copyright © 2012 S. Karger AG, Basel.

  17. Hydroxyurea as a first-line treatment of extramedullary hematopoiesis in patients with beta thalassemia: Four case reports.

    Science.gov (United States)

    Karimi, Mehran; Cohan, Nader; Pishdad, Parisa

    2015-01-01

    Extramedullary hematopoiesis (EMH) is evidenced by erythropoietic masses, which occurs as a compensatory mechanism to overcome hypoxia during chronic anemia. EMH masses in spinal cord could lead to cord compression and neurological symptoms. Besides transfusion, radiotherapy, and surgery, hydroxyurea (HU) is also a treatment strategy in EMH. We described four cases of beta thalassemia with EMH who were treated with HU as a monotherapy. INTERVENTION (AND TECHNIQUE): HU therapy was done in all patients without any transfusion during therapy. HU is a good treatment option for patients with EMH and it could be a substitute for radiotherapy and invasive surgery or regular blood transfusion.

  18. Cyclic voltammetry of dental amalgams.

    Science.gov (United States)

    Horasawa, N; Nakajima, H; Ferracane, J L; Takahashi, S; Okabe, T

    1996-05-01

    This study used cyclic voltammetry to examine the effect of the composition of dental amalgams on their electrochemical behavior, including reactions occurring outside of oral conditions. Amalgams (residual mercury 47.5%) were prepared using two low-copper (3 wt% Cu) powders and five high-copper powders (40-80 wt% Ag, 12-30 wt% Cu) with and without zinc (1.5 wt%). Cyclic voltammograms were obtained at 37 degrees C in 1.0% NaCl scanning at 2 mV/s in the potential range from -1.5 V to +0.8 V vs. Ag/AgCl. During the anodic scans, AgCl and Hg2Cl2 films were formed on all amalgams except the one with only 40 wt% Ag. In all high-copper amalgams, a prominent Cu (oxidation) peak was found at -0.1 V, indicating the release of copper during corrosion. Zinc affected the oxidation process for both low- and high-copper amalgams. When zinc was absent, a peak for Sn2+ oxidation appeared at -0.4 V. When zinc was present, a Sn4+ oxidation peak was revealed at -0.6 V. In some amalgams, there was evidence of the selective corrosion (pitting corrosion) of tin and copper. In the lowest silver-content amalgam, no protective films were formed, which is indicative of its poor corrosion resistance. As expected, in all the low-copper amalgams, an extreme increase in current density was recorded immediately at 0 V, due to the release of tin from gamma 2. Cyclic voltammetry is useful for the rapid examination (less than an hour) of the electrochemical behavior of amalgams, specifically to obtain information on the formation of compounds and the sequences of electrochemical reactions.

  19. On numerically pluricanonical cyclic coverings

    International Nuclear Information System (INIS)

    Kulikov, V S; Kharlamov, V M

    2014-01-01

    We investigate some properties of cyclic coverings f:Y→X (where X is a complex surface of general type) branched along smooth curves B⊂X that are numerically equivalent to a multiple of the canonical class of X. Our main results concern coverings of surfaces of general type with p g =0 and Miyaoka-Yau surfaces. In particular, such coverings provide new examples of multi-component moduli spaces of surfaces with given Chern numbers and new examples of surfaces that are not deformation equivalent to their complex conjugates

  20. On charge-3 cyclic monopoles

    International Nuclear Information System (INIS)

    Braden, H W; D'Avanzo, Antonella; Enolski, V Z

    2011-01-01

    We determine the spectral curve of charge-3 BPS su(2) monopoles with C 3 cyclic symmetry. The symmetry means that the genus 4 spectral curve covers a (Toda) spectral curve of genus 2. A well adapted homology basis is presented enabling the theta functions and monopole data of the genus 4 curve to be given in terms of genus 2 data. The Richelot correspondence, a generalization of the arithmetic mean, is used to solve for this genus 2 curve. Results of other approaches are compared

  1. A system for cyclical voltametry

    International Nuclear Information System (INIS)

    Silva, R.P. da; Chierice, G.O.

    1974-01-01

    The constrution of a system composed by two instruments, voltametric circuit and potenciostate is depicted. Both instruments junction joined so that the voltametric circuit works as a triangular pulse generator, capable of operating with independent ascendant and descendant slope change, with unique pulse of continuous regime. The circuit of the potenciostate is composed of an amplifier with high entrance impedance and capable of supplying relatively high currents at the exit. The equipment was tested to study the aqueous Pb 2+ system in mercury electrode. this system depicted for the cyclical-voltometry technique set in use at I.E.A., Sao Paulo (Brazil), has very good linearity

  2. Searching for world domination

    CERN Multimedia

    Quillen, E

    2004-01-01

    "Optimists might believe Microsoft suffered a setback last week that will impede its progress toward world domination, but I suspect the company has already found a way to prevail. At issue before the European Union was Microsoft's bundling of its Windows Media Player with its operating system" (1 page)

  3. Iron dominated magnets

    International Nuclear Information System (INIS)

    Fischer, G.E.

    1985-07-01

    These two lectures on iron dominated magnets are meant for the student of accelerator science and contain general treatments of the subjects design and construction. The material is arranged in the categories: General Concepts and Cost Considerations, Profile Configuration and Harmonics, Magnetic Measurements, a few examples of ''special magnets'' and Materials and Practices. Extensive literature is provided

  4. Autosomal dominant polycystisk nyresygdom

    DEFF Research Database (Denmark)

    Naver, Signe Vinsand; Ørskov, Bjarne; Jensen, Anja Møller

    2017-01-01

    Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic disorder which causes end stage renal disease. In Denmark, estimated 5,000 patients are living with the disease. Most of the patients are in regular contact with physicians due to the progression of kidney failure...

  5. Cyclic AMP in rat pancreatic islets

    International Nuclear Information System (INIS)

    Grill, V.; Borglund, E.; Cerasi, E.; Uppsala Univ.

    1977-01-01

    The incorporation of [ 3 H]adenine into cyclic AMP was studied in rat pancreatic islets under varying conditions of labeling. Prolonging the exposure to [ 3 H]adenine progressively augmented the islet cyclic [ 3 H]AMP level. Islets labeled for different periods of time and subsequently incubated (without adenine) in the presence of D-glucose or cholera toxin showed stimulations of intra-islet cyclic [ 3 H]AMP that were proportionate to the levels of radioactive nucleotide present under non-stimulatory conditions. Labeling the islets in a high glucose concentration (27.7 mM) did not modify the nucleotide responses to glucose or cholera toxin. The specific activity of cyclic [ 3 H]AMP, determined by simultaneous assay of cyclic [ 3 H]AMP and total cyclic AMP, was not influenced by glucose or cholera toxin. Glucose had no effect on the specific activity of labeled ATP

  6. The Cyclical Characteristics of Universal Social Insurance

    OpenAIRE

    Richard Hemming

    2013-01-01

    This paper examines how a universal social insurance program proposed for Mexico can respond to cyclical variations in revenue while remaining selffinancing. More specifically, it discusses the issues involved in setting up a stabilization fund that can accumulate surpluses when revenue is cyclically high, which can be drawn down when revenue is cyclically low. Attention is also paid to the options available to create a fund with sufficient resources to respond to revenue shocks early it its ...

  7. Cyclic plasticity and fatigue of metals

    International Nuclear Information System (INIS)

    Mughrabi, H.

    1993-01-01

    This report is a survey of the cyclic deformation and fatigue behaviour of selected engineering steels and alloys. Emphasis is placed on the important roles of the cyclic slip mode and the stability of the microstructure during cyclic stressing and on the conditions of fatigue testing with respect to the failure mechanisms and fatigue life. The examples presented include low-temperature fatigue, high-temperature fatigue in the presence of dynamic strain ageing and thermomechanical fatigue. (orig.)

  8. Cyclic Vomiting Syndrome in Children

    Directory of Open Access Journals (Sweden)

    T.V. Sorokman

    2016-08-01

    Full Text Available Introduction. Cyclic vomiting syndrome (CVS — is a fairly common disease of unknown etiology that affects children of all age groups and sometimes adult population and refers to the functional disorders of the gastrointestinal tract. Objective: to evaluate the effectiveness of the usage of Rehydron Optim for oral rehydration therapy in children. Materials and methods. The treatment of 40 children aged 3 to 11 years with CVS (15 persons and primary acetonemic syndrome (25 persons in the period of acetonemic crisis, including 15 boys and 25 girls, was analyzed. All children were observed in the outpatient department of the Regional children’s hospital of Chernivtsi. Diagnosis was established based on anamnesis, clinical and laboratory data. Patients underwent required clinico-biological tests and instrumental examinations. The dynamics of the following syndromes was investigated: pain, vomiting, dehydration and intoxication. Rehydration therapy in all cases was oral with the usage of Rehydron Optim. Results of the study and their discussion. A cyclical vomiting was observed in children with primary acetonemic syndrome with satisfactory condition in attack-free period. Migraine-like headaches prevailed in 36 patients (80 %, and the age of these patients was older than 7 years. Same children had episodes of paroxysmal autonomic failure. Almost all surveyed children had in their family history the risk factors for CVS development. All children had positive dynamics of the main basic clinical manifestations on the background of oral rehydration therapy using Rehydron Optim. Within the 1st day of oral rehydration therapy with Rehydron Optim in children, we have noted a significant decrease in the incidence of lethargy, vomiting, spastic abdominal pain, smell of acetone in the exhaled air (p < 0.05. In children with the I degree of dehydration, clinical signs of dehydration were not seen before the treatment, and children with the II degree had an

  9. Modeling Cyclic Variation of Intracranial Pressure

    National Research Council Canada - National Science Library

    Daley, M

    2001-01-01

    ...) recording during mechanical ventilation are due to cyclic extravascular compressional modulation primarily of the cerebral venous bed, an established isovolumetric model of cerebrospinal fluid...

  10. Behaviour of Cohesionless Soils During Cyclic Loading

    DEFF Research Database (Denmark)

    Shajarati, Amir; Sørensen, Kris Wessel; Nielsen, Søren Kjær

    Offshore wind turbine foundations are typically subjected to cyclic loading from both wind and waves, which can lead to unacceptable deformations in the soil. However, no generally accepted standardised method is currently available, when accounting for cyclic loading during the design of offshore...... wind turbine foundations. Therefore a literature study is performed in order to investigate existing research treating the behaviour of cohesionless soils, when subjected to cyclic loading. The behaviour of a soil subjected to cyclic loading is found to be dependent on; the relative density, mean...

  11. ZIP8 zinc transporter: indispensable role for both multiple-organ organogenesis and hematopoiesis in utero.

    Directory of Open Access Journals (Sweden)

    Marina Gálvez-Peralta

    Full Text Available Previously this laboratory characterized Slc39a8-encoded ZIP8 as a Zn(2+/(HCO(3(-(2 symporter; yet, the overall physiological importance of ZIP8 at the whole-organism level remains unclear. Herein we describe the phenotype of the hypomorphic Slc39a8(neo/neo mouse which has retained the neomycin-resistance gene in intron 3, hence causing significantly decreased ZIP8 mRNA and protein levels in embryo, fetus, placenta, yolk sac, and several tissues of neonates. The Slc39a8(neo allele is associated with diminished zinc and iron uptake in mouse fetal fibroblast and liver-derived cultures; consequently, Slc39a8(neo/neo newborns exhibit diminished zinc and iron levels in several tissues. Slc39a8(neo/neo homozygotes from gestational day(GD-11.5 onward are pale, growth-stunted, and die between GD18.5 and 48 h postnatally. Defects include: severely hypoplastic spleen; hypoplasia of liver, kidney, lung, and lower limbs. Histologically, Slc39a8(neo/neo neonates show decreased numbers of hematopoietic islands in yolk sac and liver. Low hemoglobin, hematocrit, red cell count, serum iron, and total iron-binding capacity confirmed severe anemia. Flow cytometry of fetal liver cells revealed the erythroid series strikingly affected in the hypomorph. Zinc-dependent 5-aminolevulinic acid dehydratase, required for heme synthesis, was not different between Slc39a8(+/+ and Slc39a8(neo/neo offspring. To demonstrate further that the mouse phenotype is due to ZIP8 deficiency, we bred Slc39a8(+/neo with BAC-transgenic BTZIP8-3 line (carrying three extra copies of the Slc39a8 allele; this cross generated viable Slc39a8(neo/neo_BTZIP8-3(+/+ pups showing none of the above-mentioned congenital defects-proving Slc39a8(neo/neo causes the described phenotype. Our study demonstrates that ZIP8-mediated zinc transport plays an unappreciated critical role during in utero and neonatal growth, organ morphogenesis, and hematopoiesis.

  12. Theory of cyclic creep of concrete based on Paris law for fatigue growth of subcritical microcracks

    Science.gov (United States)

    Bazant, Zdenek P.; Hubler, Mija H.

    2014-02-01

    Recent investigations prompted by a disaster in Palau revealed that worldwide there are 69 long-span segmental prestressed-concrete box-girder bridges that suffered excessive multi-decade deflections, while many more surely exist. Although the excessive deflections were shown to be caused mainly by obsolescence of design recommendations or codes for static creep, some engineers suspect that cyclic creep might have been a significant additional cause. Many investigators explored the cyclic creep of concrete experimentally, but a rational mathematical model that would be anchored in the microstructure and would allow extrapolation to a 100-year lifetime is lacking. Here it is assumed that the cause of cyclic creep is the fatigue growth of pre-existing microcracks in hydrated cement. The resulting macroscopic strain is calculated by applying fracture mechanics to the microcracks considered as either tensile or, in the form of a crushing band, as compressive. This leads to a mathematical model for cyclic creep in compression, which is verified and calibrated by laboratory test data from the literature. The cyclic creep is shown to be proportional to the time average of stress and to the 4th power of the ratio of the stress amplitude to material strength. The power of 4 is supported by the recent finding that, on the atomistic scale, the Paris law should have the exponent of 2 and that the exponent must increase due to scale bridging. Exponent 4 implies that cyclic creep deflections are enormously sensitive to the relative amplitude of the applied cyclic stress. Calculations of the effects of cyclic creep in six segmental prestressed concrete box girders indicate that, because of self-weight dominance, the effect on deflections absolutely negligible for large spans (>150m). For small spans (bridges upward deflections. However, the cyclic creep is shown to cause in bridges with medium and small spans (<80m) a significant residual tensile strain which can produce

  13. [Dominant Thalamus and Aphasia].

    Science.gov (United States)

    Nakano, Akiko; Shimomura, Tatsuo

    2015-12-01

    Many studies have shown that lesions of the dominant thalamus precipitate language disorders in a similar manner to transcortical aphasias, in a phenomenon known as "thalamic aphasia." In some cases, however, aphasia may not occur or may appear transiently following thalamic lesions. Furthermore, dominant thalamic lesions can produce changes in character, as observed in patients with amnesic disorder. Previous work has explored the utility of thalamic aphasia as a discriminative feature for classification of aphasia. Although the thalamus may be involved in the function of the brainstem reticular activating system and play a role in attentional network and in memory of Papez circuit or Yakovlev circuit, the mechanism by which thalamic lesion leads to the emergence of aphasic disorders is unclear. In this review, we we survey historical and recent literature on thalamic aphasia in an attempt to understand the neural processes affected by thalamic lesions.

  14. Autosomal dominant cramping disease.

    Science.gov (United States)

    Ricker, K; Moxley, R T

    1990-07-01

    A family was studied in which four generations (16 of 41 members) suffered from painful recurrent muscle cramping. A clear pattern of autosomal dominant inheritance was noted. The cramping first developed during adolescence or early adulthood. Electromyographic analysis indicated a neurogenic origin. The cramps seemed to be due to dysfunction of the motor neurons. The mechanisms underlying this alteration are unclear and require further investigation.

  15. Dominant optic atrophy

    DEFF Research Database (Denmark)

    Lenaers, Guy; Hamel, Christian; Delettre, Cécile

    2012-01-01

    DEFINITION OF THE DISEASE: Dominant Optic Atrophy (DOA) is a neuro-ophthalmic condition characterized by a bilateral degeneration of the optic nerves, causing insidious visual loss, typically starting during the first decade of life. The disease affects primary the retinal ganglion cells (RGC) an......) and their axons forming the optic nerve, which transfer the visual information from the photoreceptors to the lateral geniculus in the brain....

  16. Public owners will dominate

    International Nuclear Information System (INIS)

    Bakken, Stein Arne

    2003-01-01

    In ten years there will still be a dominating public ownership in the energy supply sector in Norway. Statkraft will be the big actor. Norway will then be integrated in an European power market through more cables and the power price will be lower and more stable. The market will be important, but within frames set by the politicians. This article quotes the views of two central figures in the energy sector on the energy supply industry in 2014

  17. Investigating cyclic nucleotide and cyclic dinucleotide binding to HCN channels by surface plasmon resonance.

    Directory of Open Access Journals (Sweden)

    Sebastien Hayoz

    Full Text Available Hyperpolarization-activated cyclic nucleotide-modulated (HCN channels control cardiac and neuronal rhythmicity. HCN channels contain cyclic nucleotide-binding domain (CNBD in their C-terminal region linked to the pore-forming transmembrane segment with a C-linker. The C-linker couples the conformational changes caused by the direct binding of cyclic nucleotides to the HCN pore opening. Recently, cyclic dinucleotides were shown to antagonize the effect of cyclic nucleotides in HCN4 but not in HCN2 channels. Based on the structural analysis and mutational studies it has been proposed that cyclic dinucleotides affect HCN4 channels by binding to the C-linker pocket (CLP. Here, we first show that surface plasmon resonance (SPR can be used to accurately measure cyclic nucleotide binding affinity to the C-linker/CNBD of HCN2 and HCN4 channels. We then used SPR to investigate cyclic dinucleotide binding in HCN channels. To our surprise, we detected no binding of cyclic dinucleotides to the isolated monomeric C-linker/CNBDs of HCN4 channels with SPR. The binding of cyclic dinucleotides was further examined with isothermal calorimetry (ITC, which indicated no binding of cyclic dinucleotides to both monomeric and tetrameric C-linker/CNBDs of HCN4 channels. Taken together, our results suggest that interaction of the C-linker/CNBD with other parts of the channel is necessary for cyclic-dinucleotide binding in HCN4 channels.

  18. Autosomal Dominant Polycystic Kidney Disease

    Science.gov (United States)

    ... RePORT NIH Fact Sheets Home > Autosomal Dominant Polycystic Kidney Disease Small Text Medium Text Large Text Autosomal Dominant Polycystic Kidney Disease YESTERDAY Autosomal Dominant Polycystic Kidney Disease (ADPKD) resulted ...

  19. Cyclic nucleotide content of tobacco BY-2 cells.

    Science.gov (United States)

    Richards, Helen; Das, Swadipa; Smith, Christopher J; Pereira, Louisa; Geisbrecht, Alan; Devitt, Nicola J; Games, David E; van Geyschem, Jan; Gareth Brenton, A; Newton, Russell P

    2002-11-01

    The cyclic nucleotide content of cultured tobacco bright yellow-2 (BY-2) cells was determined, after freeze-killing, perchlorate extraction and sequential chromatography, by radioimmunoassay. The identities of the putative cyclic nucleotides, adenosine 3',5'-cyclic monophosphate (cyclic AMP), guanosine 3',5'-cyclic monophosphate (cyclic GMP) and cytidine 3',5'-cyclic monophosphate (cyclic CMP) were unambiguously confirmed by tandem mass spectrometry. The potential of BY-2 cell cultures as a model system for future investigations of cyclic nucleotide function in higher plants is discussed.

  20. What do we know about the participation of hematopoietic stem cells in hematopoiesis? [version 1; referees: 2 approved, 1 approved with reservations

    Directory of Open Access Journals (Sweden)

    Nina Drize

    2015-10-01

    Full Text Available The demonstrated presence in adult tissues of cells with sustained tissue regenerative potential has given rise to the concept of tissue stem cells. Assays to detect and measure such cells indicate that they have enormous proliferative potential and usually an ability to produce all or many of the mature cell types that define the specialized functionality of the tissue. In the hematopoietic system, one or only a few cells can restore lifelong hematopoiesis of the whole organism. To what extent is the maintenance of hematopoietic stem cells required during normal hematopoiesis? How does the constant maintenance of hematopoiesis occur and what is the behavior of the hematopoietic stem cells in the normal organism? How many of the hematopoietic stem cells are created during the development of the organism? How many hematopoietic stem cells are generating more mature progeny at any given moment? What happens to the population of hematopoietic stem cells in aging? This review will attempt to describe the results of recent research which contradict some of the ideas established over the past 30 years about how hematopoiesis is regulated.

  1. Extramedullary hematopoiesis presented as cytopenia and massive paraspinal masses leading to cord compression in a patient with hereditary persistence of fetal hemoglobin

    OpenAIRE

    Katchi, Tasleem; Kolandaivel, Krishna; Khattar, Pallavi; Farooq, Taliya; Islam, Humayun; Liu, Delong

    2016-01-01

    Background Extramedullary hematopoeisis (EMH) can occur in various physiological and pathologic states. The spleen is the most common site of EMH. Case presentation We report a case with hereditary persistence of fetal hemoglobin with extramedullary hematopoiesis presented as cord compression and cytopenia secondary to multi-paraspinal masses. Conclusion Treatment can be a challenge. Relapse is a possibility.

  2. Extramedullary hematopoiesis presented as cytopenia and massive paraspinal masses leading to cord compression in a patient with hereditary persistence of fetal hemoglobin.

    Science.gov (United States)

    Katchi, Tasleem; Kolandaivel, Krishna; Khattar, Pallavi; Farooq, Taliya; Islam, Humayun; Liu, Delong

    2016-01-01

    Extramedullary hematopoeisis (EMH) can occur in various physiological and pathologic states. The spleen is the most common site of EMH. We report a case with hereditary persistence of fetal hemoglobin with extramedullary hematopoiesis presented as cord compression and cytopenia secondary to multi-paraspinal masses. Treatment can be a challenge. Relapse is a possibility.

  3. Activation of adenosine A3 receptors supports hematopoiesis-stimulating effects of granulocyte colony-stimulating factor in sublethally irradiated mice

    Czech Academy of Sciences Publication Activity Database

    Hofer, Michal; Pospíšil, Milan; Šefc, L.; Dušek, L.; Vacek, Antonín; Holá, Jiřina; Hoferová, Zuzana; Štreitová, Denisa

    2010-01-01

    Roč. 86, č. 8 (2010), s. 649-656 ISSN 0955-3002 R&D Projects: GA ČR(CZ) GA305/08/0158 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : ionising radiation * hematopoiesis * adenosine A3 receptors Subject RIV: BO - Biophysics Impact factor: 1.861, year: 2010

  4. CYCLICAL SUBNORMAL SEPARATION IN A-GROUPS

    African Journals Online (AJOL)

    :-at are split extensions of certain abelian p-groups by a metabelian pi-group, to satisfy the cyclic a1 subnormal separation condition. There is also a result which shows that A-groups with elementary abelian Sylow subgroups are. :icl~cally separated. KEYWORD: A-groups, Cyclical~Subnormal Separation, CS,-groups.

  5. Interactions of Cyclic Hydrocarbons with Biological Membranes

    NARCIS (Netherlands)

    SIKKEMA, J; DEBONT, JAM; POOLMAN, B

    1994-01-01

    Many cyclic hydrocarbons, e.g. aromatics, cycloalkanes, and terpenes, are toxic to microorganisms. The primary site of the toxic action is probably the cytoplasmic membrane, but the mechanism of the toxicity is still poorly understood. The effects of cyclic hydrocarbons were studied in liposomes

  6. Fractional behaviour at cyclic stretch-bending

    NARCIS (Netherlands)

    Emmens, W.C.; van den Boogaard, Antonius H.; Kazantzis, A.V.; de Hosson, J.Th.M.; Kolleck, R

    2010-01-01

    The fractional behaviour at cyclic stretch-bending has been studied by performing tensile tests at long specimens that are cyclically bent at the same time, on mild steel, dual-phase steel, stainless steel, aluminium and brass. Several types of fracture are observed, these are discussed, as are the

  7. Synthesis of cyclic alpha-MSH peptides

    NARCIS (Netherlands)

    Schaaper, W.M.M.; Adan, R.A.H.; Posthuma, T.A.; Oosterom, J.; Gispen, W.H.; Meloen, R.H.

    1998-01-01

    Cyclic lactam analogs of α-melanocyte stimulating hormone (α-MSH) have been shown to be potent agonists in the frog skin bioassay [Al-Obeidi, F. et al., J. Med. Chem., 32 (1989) 2555], demonstrating melanocortin-1 (MC1) receptor activity. We synthesized cyclic α-MSH(1-13) and α-MSH(4-10) lactam

  8. Synthesis of cyclic α-MSH peptides

    NARCIS (Netherlands)

    Gispen, W.H.; Schaaper, W.M.M..; Adan, R.A.H.; Posthuma, T.A.; Oosterom, J.; Meloen, R.H.

    1998-01-01

    Cyclic lactam analogs of -melanocyte stimulating hormone (-MSH) have been shown to be potent agonists in the frog skin bioassay [Al-Obeidi, F. et al., J. Med. Chem., 32 (1989) 2555], demonstrating melanocortin-1 (MC1) receptor activity. We synthesized cyclic -MSH(1-13) and -MSH(4-10) lactam analogs.

  9. Dominating biological networks.

    Directory of Open Access Journals (Sweden)

    Tijana Milenković

    Full Text Available Proteins are essential macromolecules of life that carry out most cellular processes. Since proteins aggregate to perform function, and since protein-protein interaction (PPI networks model these aggregations, one would expect to uncover new biology from PPI network topology. Hence, using PPI networks to predict protein function and role of protein pathways in disease has received attention. A debate remains open about whether network properties of "biologically central (BC" genes (i.e., their protein products, such as those involved in aging, cancer, infectious diseases, or signaling and drug-targeted pathways, exhibit some topological centrality compared to the rest of the proteins in the human PPI network.To help resolve this debate, we design new network-based approaches and apply them to get new insight into biological function and disease. We hypothesize that BC genes have a topologically central (TC role in the human PPI network. We propose two different concepts of topological centrality. We design a new centrality measure to capture complex wirings of proteins in the network that identifies as TC those proteins that reside in dense extended network neighborhoods. Also, we use the notion of domination and find dominating sets (DSs in the PPI network, i.e., sets of proteins such that every protein is either in the DS or is a neighbor of the DS. Clearly, a DS has a TC role, as it enables efficient communication between different network parts. We find statistically significant enrichment in BC genes of TC nodes and outperform the existing methods indicating that genes involved in key biological processes occupy topologically complex and dense regions of the network and correspond to its "spine" that connects all other network parts and can thus pass cellular signals efficiently throughout the network. To our knowledge, this is the first study that explores domination in the context of PPI networks.

  10. Cyclic completion of the anamorphic universe

    Science.gov (United States)

    Ijjas, Anna

    2018-04-01

    Cyclic models of the universe have the advantage of avoiding initial conditions problems related to postulating any sort of beginning in time. To date, the best known viable examples of cyclic models have been ekpyrotic. In this paper, we show that the recently proposed anamorphic scenario can also be made cyclic. The key to the cyclic completion is a classically stable, non-singular bounce. Remarkably, even though the bounce construction was originally developed to connect a period of contraction with a period of expansion both described by Einstein gravity, we show here that it can naturally be modified to connect an ordinary contracting phase described by Einstein gravity with a phase of anamorphic smoothing. The paper will present the basic principles and steps in constructing cyclic anamorphic models.

  11. On dominator colorings in graphs

    Indian Academy of Sciences (India)

    A dominator coloring of a graph is a proper coloring of in which every vertex dominates every vertex of at least one color class. The minimum number of colors required for a dominator coloring of is called the dominator chromatic number of and is denoted by d ( G ) . In this paper we present several results on ...

  12. The role of Ikaros transcriptional factor in normal hematopoiesis and leukemogenesis: biological and clinical aspects

    Directory of Open Access Journals (Sweden)

    V. S. Vshivkoo

    2015-01-01

    Full Text Available Investigation of the pathogenesis and factors effecting recurrence, progression and drug resistance in acute leukemia (AL remains a major challenge for hematology and other related areas. The role of more than 50 genes and proteins in the AL pathogenesis has been shown, including the well-studied tumor suppressor (CDKN2A/CDKN2B, RB1, PTEN, p53, and classical fusion genes (BCR/ABL1, TEL/AML1, E2A/PBX, MLL translocations. In addition, high frequency of aberrations in genes responsible for lymphoid differentiation have been identified such as transcription factors (PAX5, IKZF1 and EBF1, transcriptional regulation of the genes (ETV6, ERG, and signaling pathways of antigen receptors (BTLA, CD200, TOX, BLNK, VPREB1, as well as genes involved in chemoresistance of leukemia cells (NR3C1. In recent studies, Ikaros abnormalities have been reported to be frequently associated with AL. Ikaros is a member of a Kruppel-like family of zinc finger transcription factors that also includes IKZF2 (Helios, IKZF3 (Aiolos, Eos and Pegasus, and encoded by the IKZF1 gene. In hematopoietic cells Ikaros functions as a transcription factor, a key protein controlling T-, B-, NK-, and dendritic cells early differentiation. At the early hematopoiesis stages, it represses the myeloid and erythroid lineages, and stimulates the lymphoid differentiation. Ikaros also normally modulates immune response and plays role of a tumor suppressor in lymphoid malignances. Data from numerous clinical studies confirmed an association between the presence of IKZF1 aberrations and B-cell and, to a lesser extent, T-cell acute lymphoblastic leukemia (ALL development. Besides, loss of Ikaros function was associated with progression of myeloproliferative diseases to acute myeloid leukemia (AML in children. From clinical point of view, particular intragenic IKZF1 deletions and a short (non-functional protein Ikaros isoforms, which may occur as a result of intragenic deletions or aberrant splicing

  13. Focal extra-axial hemorrahagic mass with subdural hemorrhage secondare to extramedullary hematopoiesis in idiopathic myelodysplastic sindrome.

    Science.gov (United States)

    Di Ieva, A; Di Lieva, A; Aimar, E; Tancioni, F; Levi, D; Debernardi, A; Pisano, P; Rahal, D; Nozza, A; Magagnoli, M; Gaetani, P

    2007-03-01

    Idiopathic myelodysplastic syndrome is a disease characterized by a clonal stem cell disorder in which megacaryocitic and granulocytic lineages are mainly involved; extramedullary myeloid metaplasia is due to abnormal location of myeloid tissue in other organs than bone marrow. Rarely the central nervous system is involved. When it happens, it is typical to find masses around the brain and pachymeningeal thickening, but it is very rare to find it associated with subdural haemorrhage, as in the case we describe in the present article. Considering our case and the literature we can suggest that radiological images associated with the clinical history of the patient suggestive for extramedullary hematopoiesis can be sufficient for a correct diagnosis and for a radiotherapy treatment, demanding surgery in the case of diagnostic doubts, massive hemorrahages or neurological decifits caused by the focal lesions.

  14. Bone marrow stroma in childhood myelodysplastic syndrome: composition, ability to sustain hematopoiesis in vitro, and altered gene expression.

    Science.gov (United States)

    Borojevic, Radovan; Roela, Rosimeire A; Rodarte, Renato S; Thiago, Leandro S; Pasini, Fátima S; Conti, Fabiana M; Rossi, Maria Isabel D; Reis, Luiz F L; Lopes, Luiz F; Brentani, M Mitzi

    2004-08-01

    We studied bone marrow stromal cell cultures from patients with childhood myelodysplastic syndromes (MDS, refractory anemia with excess of blasts, RAEB) and from matched normal donors. Stromal cell monolayers were characterized as myofibroblasts by the expression of smooth muscle alpha-actin, collagen IV, laminin and fibronectin. When normal cord blood cells were plated onto myelodysplastic stromas, a pathologic cell differentiation was observed, indicating altered myelosupportive properties. cDNA array analysis showed that patient stromas expressed increased levels of thrombospondin-1, collagen-I alpha2-chain, osteoblast-specific factor-2 and osteonectin, indicating the presence of increased osteoblast content, as confirmed by enhanced alkaline phosphatase synthesis. Alterations in the myelodysplastic stroma environment might contribute to abnormal hematopoiesis in this pathology.

  15. A persistent cough as atypical clinical presentation of intrathoracic extramedullary hematopoiesis (EMH) in a female with thalassemia intermedia.

    Science.gov (United States)

    Abdulla, Mohammad Aj; Yassin, Mohamed A; Abdelrazek, Mohamed; Mudawi, Deena; Ibrahim, Firyal; Soliman, Dina S; ElOmri, Halima; Nashwan, Abdulqadir J; Fernihough, Liam; De Sanctis, Vincenzo; Soliman, Ashraf T

    2018-02-16

    Extramedullary hematopoiesis (EMH) is a rare disorder, defined as the appearance of hematopoietic elements outside the bone marrow or peripheral blood. The most common sites of EMH are liver and spleen, but it has been documented in other organs such as the mediastinum, lymph nodes, breast, and central nervous system. EMH occurs as a compensatory mechanism for bone marrow dysfunction in severe thalassemia. We report a case of EMH presenting as a posterior mediastinal mass in a 34-year-old woman with thalassemia intermedia with chronic cough and shortness of breath on exertion. The diagnosis of EMH was confirmed by a CT-guided fine needle biopsy. All symptoms disappeared after surgical removal of the mass.

  16. Intrathoracic extramedullary hematopoiesis presenting as tumor-simulating lesions of the mediastinum in α-thalassemia: A case report.

    Science.gov (United States)

    An, Jun; Weng, Yimin; He, Jinyuan; Li, Yun; Huang, Shaohong; Cai, Songwang; Zhang, Junhang

    2015-10-01

    Extramedullary hematopoiesis (EMH) is a rare disease, where hematological disorder drives extramedullary hematopoietic tumor formation in multiple regions of the body. The present study reports a case of EMH presenting as multiple tumor-like lesions of mediastinum in a 61-year-old male with α-thalassemia, which was subjected to a video-assisted thoracoscopic surgery tissue biopsy to differentiate it from other mediastinal tumors. To date, only three cases of EMH in patients with α-thalassemia have been described in the literature. Patients with EMH typically exhibit no hematological disorder preoperatively and therefore EMH is frequently misdiagnosed. In the present study, along with a literature review of the clinicopathological features of EMH, the diagnosis and treatment of this rare case was discussed, in order to differentiate diagnosis, and particularly to distinguish EHM from extramedullary myeloid sarcoma.

  17. Dynamic interaction between TAL1 oncoprotein and LSD1 regulates TAL1 function in hematopoiesis and leukemogenesis

    Science.gov (United States)

    Li, Ying; Deng, Changwang; Hu, Xin; Patel, Bhavita; Fu, Xueqi; Qiu, Yi; Brand, Marjorie; Zhao, Keji; Huang, Suming

    2012-01-01

    TAL1/SCL is a hematopoietic specific oncogene and its activity is regulated by associated transcriptional coactivators and corepressors. Dysregulation of TAL1 activity has been associated with T cell leukemogenesis. However, it remains unclear how the interactions between TAL1 and corepressors versus coactivators are properly regulated. Here we reported that PKA mediated phosphorylation regulates TAL1 interaction with the lysine specific demethylase (LSD1) that removes methyl group from methylated Lys 4 on histone H3 tails. Phosphorylation of serine 172 in TAL1 specifically destabilizes the TAL1-LSD1 interaction leading to promoter H3K4 hypermethylation and activation of target genes that have been suppressed in normal and malignant hematopoiesis. Knockdown of TAL1 or LSD1 led to a derepression of the TAL1 target genes in T cell acute lymphoblast leukemia (T-ALL) Jurkat cells, which is accompanied by elevating promoter H3K4 methylation. Similarly, treatment of PKA activator forskolin resulted in derepression of target genes by reducing its interaction with LSD1 while PKA inhibitor H89 represses them by suppressing H3K4 methylation levels. Consistent with the dual roles of TAL1 in transcription, TAL1 associated LSD1 is decreased while recruitment of hSET1 is increased at the TAL1 targets during erythroid differentiation. This process is accompanied by a dramatic increase in H3K4 methylation. Thus, our data revealed a novel interplay between PKA phosphorylation and TAL1 mediated epigenetic regulation that regulates hematopoietic transcription and differentiation programs during hematopoiesis and leukemogenesis. PMID:22310283

  18. Blood morphology and the levels of selected cytokines related to hematopoiesis in occupational short-term exposure to lead

    International Nuclear Information System (INIS)

    Dobrakowski, Michał; Boroń, Marta; Czuba, Zenon P.; Birkner, Ewa; Chwalba, Artur; Hudziec, Edyta; Kasperczyk, Sławomir

    2016-01-01

    The aim of the study was to investigate the influence of a short-term exposure to lead on the blood morphology and the levels of selected cytokines related to hematopoiesis in occupationally exposed workers. The study population included 37 males occupationally exposed to lead for 36 to 44 days. Their blood lead level raised from 10.7 ± 7.67 μg/dl at baseline to the level of 49.1 ± 14.1 μg/dl at the end of the study. The level of hemoglobin and values of MCH and MCHC were decreased due to a short-term exposure to lead by 2%, 2%, and 1%, respectively. The counts of WBC, LYM, and MXD increased significantly by 5%, 7%, and 35%. Similarly, the count of PLT increased by 7%, while PDW, MPV, and P-LCR decreased by 6%, 3%, and 9%, respectively. The levels of IL-7, G-CSF, HGF, PDGF AB/BB, SCF, and PECAM-1, decreased significantly by 30%, 33%, 8%, 30%, 25%, and 20%, respectively. A short-term occupational exposure to lead results in a decreased hemoglobin level and increased counts of WBC and PLT. Changes in counts and proportions of different types of leukocytes and decreased values of PLT indices, such as PDW, MPV, and P-LCR, due to the subacute lead-exposure may be associated with lead-induced decreased levels of cytokines related to hematopoiesis, including SCF, G-CSF, IL-7, and PDGF. - Highlights: • Subacute exposure to lead results in a decreased hemoglobin level. • Subacute exposure to lead results in increased counts of WBC and PLT. • Subacute exposure to lead decreases the levels of SCF, G-CSF, IL-7, and PDGF.

  19. C-X-C motif chemokine 12 influences the development of extramedullary hematopoiesis in the spleens of myelofibrosis patients.

    Science.gov (United States)

    Wang, Xiaoli; Cho, Sool Yeon; Hu, Cing Siang; Chen, Daniel; Roboz, John; Hoffman, Ronald

    2015-02-01

    Myelofibrosis (MF) is characterized by the constitutive mobilization of hematopoietic stem cells (HSC) and hematopoietic progenitor cells (HPC) and the establishment of extramedullary hematopoiesis. The mechanisms underlying this abnormal HSC/HPC trafficking pattern remain poorly understood. We demonstrated that both splenic and peripheral blood (PB) MF CD34(+) cells equally share a defective ability to home to the marrow, but not to the spleens, of NOD/LtSz-Prkdc(scid) mice. This trafficking pattern could not be attributed to discordant expression of integrins or chemokine receptors other than the downregulation of C-X-C chemokine receptor type 4 by both PB and splenic MF CD34(+) cells. The number of both splenic MF CD34(+) cells and HPCs that migrated toward splenic MF plasma was, however, significantly greater than the number that migrated toward PB MF plasma. The concentration of the intact HSC/HPC chemoattractant C-X-C motif chemokine 12 (CXCL12) was greater in splenic MF plasma than PB MF plasma, as quantified using mass spectrometry. Functionally inactive truncated products of CXCL12, which are the product of proteolytic degradation by serine proteases, were detected at similar levels in both splenic and PB MF plasma. Treatment with an anti-CXCL12 neutralizing antibody resulted in a reduction in the degree of migration of splenic MF CD34(+) cells toward both PB and splenic MF plasma, validating the role of CXCL12 as a functional chemoattractant. Our data indicate that the MF splenic microenvironment is characterized by increased levels of intact, functional CXCL12, which contributes to the localization of MF CD34(+) cells to the spleen and the establishment of extramedullary hematopoiesis. Copyright © 2015 ISEH - International Society for Experimental Hematology. Published by Elsevier Inc. All rights reserved.

  20. Undrained Cyclic Behaviour of Dense Frederikshavn Sand

    DEFF Research Database (Denmark)

    Nielsen, Søren Kjær; Ibsen, Lars Bo; Sørensen, Kris Wessel

    2013-01-01

    of undrained cyclic triaxial tests, which have been performed at the Geotechnical Laboratory at Aalborg University. In order to ensure offshore conditions, the tests were fully saturated and performed with a relative density of 80 %. During cyclic loading, special attention was given to the development of pore......A modified contour diagram is created for the Frederikshavn Sand in the undrained case for a relative density of ID = 80 %. It can be used to estimate the number of cycles to failure for a given combination of pore pressure, average and cyclic load ratio. The diagram is based on a series...

  1. Driving Force Based Design of Cyclic Distillation

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Fjordbak; Huusom, Jakob Kjøbsted; Abildskov, Jens

    2017-01-01

    Driving force based design is adopted from conventional continuous distillation to cyclic distillation. This leads to a definition of the operating line representation for the cyclic distillation process. A possible realization of the driving force design is presented, which implies operation...... with mixed phase feeds. A range of binary test cases, benzene toluene, methanol water, and ethanol water, are evaluated. The advantage of the design approach in cyclic distillation is shown to be analogous to the advantages obtained in conventional continuous distillation, including a minimal utility...

  2. Genetics Home Reference: cyclic vomiting syndrome

    Science.gov (United States)

    ... infections. Other triggers can include periods without eating (fasting), temperature extremes, lack of sleep, overexertion, allergies, ingesting ... include changes in brain function, hormonal abnormalities, and gastrointestinal problems. Many researchers believe that cyclic vomiting syndrome ...

  3. Cyclic hardening in bundled actin networks.

    Science.gov (United States)

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

    2010-01-01

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

  4. Anodic selective functionalization of cyclic amine derivatives

    OpenAIRE

    Onomura, Osamu

    2012-01-01

    Anodic reactions are desirable methods from the viewpoint of Green Chemistry, since no toxic oxidants are necessary for the oxidation of organic molecules. This review introduces usefulness of anodic oxidation and successive reaction for selective functionalization of cyclic amine derivatives.

  5. Cyclic voltammetry and reduction mechanistic studies of ...

    African Journals Online (AJOL)

    styrylpyrylium perchlorates have been evaluated using cyclic voltammetry, in comparison to their non-methylated derivatives values. The reduction peak of all studied compounds remained chemically irreversible. The presence of the ...

  6. Mortar constituent of concrete under cyclic compression

    Science.gov (United States)

    Maher, A.; Darwin, D.

    1980-10-01

    The behavior of the mortar constituent of concrete under cyclic compression was studied and a simple analytic model was developed to represent its cyclic behavior. Experimental work consisted of monotonic and cyclic compressive loading of mortar. Two mixes were used, with proportions corresponding to concretes having water cement ratios of 0.5 and 0.6. Forty-four groups of specimens were tested at ages ranging from 5 to 70 days. complete monotonic and cyclic stress strain envelopes were obtained. A number of loading regimes were investigated, including cycles to a constant maximum strain. Major emphasis was placed on tests using relatively high stress cycles. Degradation was shown to be a continuous process and a function of both total strain and load history. No stability or fatigue limit was apparent.

  7. cyclic -perimeter hydrocarbon ruthenium complexes bearing ...

    Indian Academy of Sciences (India)

    - cyclic -perimeter hydrocarbon ruthenium complexes bearing functionalized pyridyl diketones: Isolation of complexes with 2-N∩O and 4-N∩O bonding modes of ligands. Saphidabha L Nongbri Babulal Das Mohan Rao Kollipara.

  8. Clonal Dominance With Retroviral Vector Insertions Near the ANGPT1 and ANGPT2 Genes in a Human Xenotransplant Mouse Model

    Directory of Open Access Journals (Sweden)

    Reinhard Haemmerle

    2014-01-01

    Full Text Available Insertional leukemogenesis represents the major risk factor of hematopoietic stem cell (HSC based gene therapy utilizing integrating viral vectors. To develop a pre-clinical model for the evaluation of vector-related genotoxicity directly in the relevant human target cells, cord blood CD34+ HSCs were transplanted into immunodeficient NOD.SCID.IL2rg−/− (NSG mice after transduction with an LTR-driven gammaretroviral vector (GV. Furthermore, we specifically investigated the effect of prolonged in vitro culture in the presence of cytokines recently described to promote HSC expansion or maintenance. Clonality of human hematopoiesis in NSG mice was assessed by high throughput insertion site analyses and validated by insertion site-specific PCR depicting a GV typical integration profile with insertion sites resembling to 25% those of clinical studies. No overrepresentation of integrations in the vicinity of cancer-related genes was observed, however, several dominant clones were identified including two clones harboring integrations in the ANGPT1 and near the ANGPT2 genes associated with deregulated ANGPT1- and ANGPT2-mRNA levels. While these data underscore the potential value of the NSG model, our studies also identified short-comings such as overall low numbers of engrafted HSCs, limited in vivo observation time, and the challenges of in-depth insertion site analyses by low contribution of gene modified hematopoiesis.

  9. 3' : 5'-Cyclic AMP-dependent 3'

    NARCIS (Netherlands)

    Mato, José M.; Krens, Frans A.; Haastert, Peter J.M. van; Konijn, Theo M.

    1977-01-01

    Suspensions of 3':5'-cyclic AMP (cAMP)-sensitive cells of Dictyostelium discoideum responded to a cAMP pulse with increased 3':5'-cyclic GMP (cGMP) levels. Under the assay conditions used (2 × 10^8 cells per ml in 10 mM phosphate buffer, pH 6.0) cAMP (5 × 10-8 M final concentration) increased cGMP

  10. Empty Container Management in Cyclic Shipping Routes

    OpenAIRE

    Dong-Ping Song; Jing-Xin Dong

    2008-01-01

    This paper considers the empty container management problem in a cyclic shipping route. The objective is to seek the optimal empty container repositioning policy in a dynamic and stochastic situation by minimising the expected total costs consisting of inventory holding costs, demand lost-sale costs, lifting-on and lifting-off charges, and container transportation costs. A three-phase threshold control policy is developed to reposition empty containers in cyclic routes. The threshold values a...

  11. Consecutive exotropia following surgically corrected cyclic esotropia.

    Science.gov (United States)

    Post, Joel; Eidsness, Ryan B; Romanchuk, Kenneth G

    2007-01-01

    Cyclic esotropia is a rare form of strabismus consisting of regular intervals of esotropia alternating with periods of orthophoria in a rhythmic/cyclic manner. In the vast majority of cases, surgery appears to permanently correct the esotropia, with no sequelae after years of follow-up. We report a case of consecutive exotropia in a patient five years after bilateral medial rectus recessions for cyclic esotropia. A case report involving review of a clinical chart. A two-year-old male presented with right esotropia and mild amblyopia. He was treated with patching and following resolution of the amblyopia he developed a cyclic esotropia. Surgical correction was performed for the full amount measured on a "manifest" day. Following the surgery, he was orthophoric and demonstrated binocular vision. He remained stable for five years, and then returned with occasional diplopia and an intermittent exotropia. Cyclic esotropia is a rare disorder of ocular motility that spontaneously appears and disappears at regular intervals. After surgical correction, the deviation disappears and recurrence of esotropia is very infrequent. We present the first reported case of consecutive exotropia following surgical correction of a cyclic esotropia.

  12. On dominator colorings in graphs

    Indian Academy of Sciences (India)

    A dominator coloring of a graph G is a proper coloring of G in which every vertex dominates every vertex of at least one color class. The minimum number of colors required for a dominator coloring of G is called the dominator chromatic number of G and is denoted by χd(G). In this paper we present several results on graphs ...

  13. Perfect secure domination in graphs

    Directory of Open Access Journals (Sweden)

    S.V. Divya Rashmi

    2017-07-01

    Full Text Available Let $G=(V,E$ be a graph. A subset $S$ of $V$ is a dominating set of $G$ if every vertex in $Vsetminus  S$ is adjacent to a vertex in $S.$ A dominating set $S$ is called a secure dominating set if for each $vin Vsetminus S$ there exists $uin S$ such that $v$ is adjacent to $u$ and $S_1=(Ssetminus{u}cup {v}$ is a dominating set. If further the vertex $uin S$ is unique, then $S$ is called a perfect secure dominating set. The minimum cardinality of a perfect secure dominating set of $G$ is called the perfect  secure domination number of $G$ and is denoted by $gamma_{ps}(G.$ In this paper we initiate a study of this parameter and present several basic results.

  14. Molecular Simulations of Cyclic Loading Behavior of Carbon Nanotubes Using the Atomistic Finite Element Method

    Directory of Open Access Journals (Sweden)

    Jianfeng Wang

    2009-01-01

    Full Text Available The potential applications of carbon nanotubes (CNT in many engineered bionanomaterials and electromechanical devices have imposed an urgent need on the understanding of the fatigue behavior and mechanism of CNT under cyclic loading conditions. To date, however, very little work has been done in this field. This paper presents the results of a theoretical study on the behavior of CNT subject to cyclic tensile and compressive loads using quasi-static molecular simulations. The Atomistic Finite Element Method (AFEM has been applied in the study. It is shown that CNT exhibited extreme cyclic loading resistance with yielding strain and strength becoming constant within limited number of loading cycles. Viscoelastic behavior including nonlinear elasticity, hysteresis, preconditioning (stress softening, and large strain have been observed. Chiral symmetry was found to have appreciable effects on the cyclic loading behavior of CNT. Mechanisms of the observed behavior have been revealed by close examination of the intrinsic geometric and mechanical features of tube structure. It was shown that the accumulated residual defect-free morphological deformation was the primary mechanism responsible for the cyclic failure of CNT, while the bond rotating and stretching experienced during loading/unloading played a dominant role on the strength, strain and modulus behavior of CNT.

  15. EphA2 Is a Therapy Target in EphA2-Positive Leukemias but Is Not Essential for Normal Hematopoiesis or Leukemia.

    Science.gov (United States)

    Charmsaz, Sara; Beckett, Kirrilee; Smith, Fiona M; Bruedigam, Claudia; Moore, Andrew S; Al-Ejeh, Fares; Lane, Steven W; Boyd, Andrew W

    2015-01-01

    Members of the Eph family of receptor tyrosine kinases and their membrane bound ephrin ligands have been shown to play critical roles in many developmental processes and more recently have been implicated in both normal and pathological processes in post-embryonic tissues. In particular, expression studies of Eph receptors and limited functional studies have demonstrated a role for the Eph/ephrin system in hematopoiesis and leukemogenesis. In particular, EphA2 was reported on hematopoietic stem cells and stromal cells. There are also reports of EphA2 expression in many different types of malignancies including leukemia, however there is a lack of knowledge in understanding the role of EphA2 in hematopoiesis and leukemogenesis. We explored the role of EphA2 in hematopoiesis by analyzing wild type and EphA2 knockout mice. Mature, differentiated cells, progenitors and hematopoietic stem cells derived from knockout and control mice were analyzed and no significant abnormality was detected. These studies showed that EphA2 does not have an obligatory role in normal hematopoiesis. Comparative studies using EphA2-negative MLL-AF9 leukemias derived from EphA2-knockout animals showed that there was no detectable functional role for EphA2 in the initiation or progression of the leukemic process. However, expression of EphA2 in leukemias initiated by MLL-AF9 suggested that this protein might be a possible therapy target in this type of leukemia. We showed that treatment with EphA2 monoclonal antibody IF7 alone had no effect on tumorigenicity and latency of the MLL-AF9 leukemias, while targeting of EphA2 using EphA2 monoclonal antibody with a radioactive payload significantly impaired the leukemic process. Altogether, these results identify EphA2 as a potential radio-therapeutic target in leukemias with MLL translocation.

  16. Total Domination Versus Paired-Domination in Regular Graphs

    Directory of Open Access Journals (Sweden)

    Cyman Joanna

    2018-05-01

    Full Text Available A subset S of vertices of a graph G is a dominating set of G if every vertex not in S has a neighbor in S, while S is a total dominating set of G if every vertex has a neighbor in S. If S is a dominating set with the additional property that the subgraph induced by S contains a perfect matching, then S is a paired-dominating set. The domination number, denoted γ(G, is the minimum cardinality of a dominating set of G, while the minimum cardinalities of a total dominating set and paired-dominating set are the total domination number, γt(G, and the paired-domination number, γpr(G, respectively. For k ≥ 2, let G be a connected k-regular graph. It is known [Schaudt, Total domination versus paired domination, Discuss. Math. Graph Theory 32 (2012 435–447] that γpr(G/γt(G ≤ (2k/(k+1. In the special case when k = 2, we observe that γpr(G/γt(G ≤ 4/3, with equality if and only if G ≅ C5. When k = 3, we show that γpr(G/γt(G ≤ 3/2, with equality if and only if G is the Petersen graph. More generally for k ≥ 2, if G has girth at least 5 and satisfies γpr(G/γt(G = (2k/(k + 1, then we show that G is a diameter-2 Moore graph. As a consequence of this result, we prove that for k ≥ 2 and k ≠ 57, if G has girth at least 5, then γpr(G/γt(G ≤ (2k/(k +1, with equality if and only if k = 2 and G ≅ C5 or k = 3 and G is the Petersen graph.

  17. Stochastic evolution of four species in cyclic competition

    International Nuclear Information System (INIS)

    Durney, C H; Case, S O; Pleimling, M; Zia, R K P

    2012-01-01

    We study the stochastic evolution of four species in cyclic competition in a well mixed environment. For systems composed of a finite number N of particles these simple interaction rules result in a rich variety of extinction scenarios, from single-species domination to coexistence between non-interacting species. Using exact results and numerical simulations we discuss the temporal evolution of the system for different values of N, and for different values of the reaction rates, as well as for different initial conditions. As expected, the stochastic evolution is found to closely follow the mean-field result for large N, with notable deviations appearing in the vicinity of extinction events. Different ways of characterizing and predicting extinction events are discussed

  18. On the equivalence of cyclic and quasi-cyclic codes over finite fields

    Directory of Open Access Journals (Sweden)

    Kenza Guenda

    2017-07-01

    Full Text Available This paper studies the equivalence problem for cyclic codes of length $p^r$ and quasi-cyclic codes of length $p^rl$. In particular, we generalize the results of Huffman, Job, and Pless (J. Combin. Theory. A, 62, 183--215, 1993, who considered the special case $p^2$. This is achieved by explicitly giving the permutations by which two cyclic codes of prime power length are equivalent. This allows us to obtain an algorithm which solves the problem of equivalency for cyclic codes of length $p^r$ in polynomial time. Further, we characterize the set by which two quasi-cyclic codes of length $p^rl$ can be equivalent, and prove that the affine group is one of its subsets.

  19. Chain dimension of cyclic polymers in solutions

    Energy Technology Data Exchange (ETDEWEB)

    Ohta, Yutaka [Department of Applied Chemistry, Nagoya University Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Masuoka, Keisuke [Department of Applied Chemistry, Nagoya University Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Takano, Atsushi [Department of Applied Chemistry, Nagoya University Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Matsushita, Yushu [Department of Applied Chemistry, Nagoya University Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)]. E-mail: yushu@apchem.nagoya-u.ac.jp

    2006-11-15

    Telechelic polystyrenes (PSs) were synthesized and cyclized by end-to-end ring closure reaction under extremely diluted condition. Cyclic PSs were isolated from coupling products by GPC fractionation and precipitational fractionation, and 4 cyclic polymers, whose molecular weights M{sub w} are covering the range 20k=cyclic polymers have high purity (over 95%) by HPLC. Their radii of gyration R{sub g} were determined in benzene-d{sub 6} (good solvent) and cyclohexane-d{sub 12} (theta solvent) by small-angle neutron scattering and light scattering. It was found that R{sub g} of cyclic polymer can be scaled with M{sub w} as R{sub g}{proportional_to}M{sub w}{sup 0.6} in benzene-d{sub 6} and as R{sub g}{proportional_to}M{sub w}{sup 0.5} in cyclohexane-d{sub 12}, both exponents being the same as for linear counterparts. However, experimentally determined contraction ratio, R{sub g(cyclic)}/R{sub g(linear)}, is smaller than the theoretical predictions.

  20. Further studies on cyclic erythropoiesis in mice

    International Nuclear Information System (INIS)

    Gibson, C.M.; Gurney, C.W.; Simmons, E.L.; Gaston, E.O.

    1985-01-01

    When young adult female W/Wv mice are given 0.5 micro+Ci 89 Sr/g body weight intravenously, their hematocrit values oscillate from nadirs of 26% to zeniths of 42% with a periodicity of 16 days. The response of the W/Wv mouse to an assortment of radioactive and hematologic stresses have been examined in an effort to understand better the pathophysiology of cyclic erythropoiesis. When the dose of 89 Sr is increased, the amplitude of cycling increases as nadirs are lowered, but periodicity is unchanged. When the dose of 89 Sr is lowered to 0.3 microCi or less, cyclic erythropoiesis of substantial amplitude is observed only after five or six microoscillations. A single hematopoietic insult of 80 rad x-irradiation coupled with phlebotomy produces a transient form of cyclic erythropoiesis, namely, a series of dampened oscillations prior to recovery. Finally, we report that Wv/Wv mice exhibit a form of cyclic erythropoiesis in response to 0.5 microCi 89 Sr/g body weight, in which the hematocrit values of successive nadirs gradually increase, and stabilize at about 100 days. 89 Sr does not induce cyclic erythropoiesis in the +/+, W/+, or W/v/+ mice, the Hertwig strain of anemic mice, or in normal BDF1 mice

  1. A quantitave analysis of the cyclical macrodynamics of the technological development of Ukraine's economy

    OpenAIRE

    N. Geseleva

    2012-01-01

    The author investigates the urgent problem of justification and quantitative analysis of mathematical regularities of cyclical technological and economic development for further development of managerial decisions on the creation of economic mechanisms to ensure accelerated introduction of technological novelties, change of the dominating outdated technologies and development of innovative high-tech waves. To investigate the change of technological waves, the author proposes a production func...

  2. The nature of solar cyclicity. I

    Science.gov (United States)

    Romanchuk, P. R.

    1981-02-01

    The report contains a critical survey of work devoted to the study of the nature of solar cyclicity. The inconsistency of the representation of cyclic curves using a frequency spectrum is indicated. The useful contribution of the ideas of Wolf, Newcomb, and Waldmeier to the solution of the problem is noted. Data are cited in favor of the theory of the tidal nature of solar cyclicity developed by the author, which also takes into account the ideas of the above-mentioned authors: the continuous paired and single tidal actions of the planets and the resonance character of this action, thanks to which the approximately 10-year period of action of Jupiter and Saturn is transformed into the 11-year activity cycle.

  3. HOST liner cyclic facilities: Facility description

    Science.gov (United States)

    Schultz, D.

    1982-01-01

    A quartz lamp box, a quartz lamp annular rig, and a low pressure liner cyclic can rig planned for liner cyclic tests are described. Special test instrumentation includes an IR-TV camera system for measuring liner cold side temperatures, thin film thermocouples for measuring liner hot side temperatures, and laser and high temperature strain gages for obtaining local strain measurements. A plate temperature of 2,000 F was obtained in an initial test of an apparatus with three quartz lamps. Lamp life, however, appeared to be limited for the standard commercial quartz lamps available. The design of vitiated and nonvitiated preheaters required for the quartz lamp annular rig and the cyclic can test rigs is underway.

  4. Cyclic distillation technology - A mini-review

    DEFF Research Database (Denmark)

    Bîldea, Costin Sorin; Pătruţ, Cătălin; Jørgensen, Sten Bay

    2016-01-01

    Process intensification in distillation systems has received much attention during the pastdecades, with the aim of increasing both energy and separation efficiency. Varioustechniques, such as internal heat-integrated distillation, membrane distillation, rotating packedbed, dividing-wall columns...... and reactive distillation were studied and reported in literature. All these techniques employ the conventional continuous counter-current contact of vapor andliquid phases. Cyclic distillation technology is based on an alternative operating mode usingseparate phase movement which leads to key practical...... advantages in both chemical andbiochemical processes. This article provides a mini-review of cyclic distillation technology.The topics covered include the working principle, design and control methods, main benefitsand limitations as well as current industrial applications. Cyclic distillation can...

  5. Cyclic cellular automata in 3D

    International Nuclear Information System (INIS)

    Reiter, Clifford A.

    2011-01-01

    Highlights: → We explore the self-organization of cyclic cellular automata in 3D. → Von Neumann, Moore and two types of intermediate neighborhoods are investigated. → Random neighborhoods self organize through phases into complex nested structures. → Demons are seen to have many alternatives in 3D. - Abstract: Cyclic cellular automata in two dimensions have long been intriguing because they self organize into spirals and that behavior can be analyzed. The form for the patterns that develop is highly dependent upon the form of the neighborhood. We extend this work to three dimensional cyclic cellular automata and observe self organization dependent upon the neighborhood type. This includes neighborhood types intermediate between Von Neumann and Moore neighborhoods. We also observe that the patterns include nested shells with the appropriate forms but that the nesting is far more complex than the spirals that occur in two dimensions.

  6. Cyclic microplasticity factors of some metals

    Energy Technology Data Exchange (ETDEWEB)

    Puskar, A. (University of Transport and Telecommunications, Zilina (Czechoslovakia))

    1983-11-01

    The measurement of the internal friction and the elasticity modulus defect together with a new approximation for evaluating the plastic deformation amplitude from the total deformation amplitude enable the cyclic deformation curves, the changes in hysteresis loop area on increasing the deformation amplitude and many other important characteristics of cyclic microplasticity to be determined during a push-pull type of loading at a frequency of 23kHz on dumb-bell shaped specimens of titanium, molybdenum, niobium and low carbon unalloyed steel.

  7. SICLOPPS cyclic peptide libraries in drug discovery.

    Science.gov (United States)

    Tavassoli, Ali

    2017-06-01

    Cyclic peptide libraries have demonstrated significant potential when employed against challenging targets such as protein-protein interactions. While a variety of methods for library generation exist, genetically encoded libraries hold several advantages over their chemically synthesized counterparts; they are more readily accessible and allow straightforward hit deconvolution. One method for the intracellular generation of such libraries is split-intein circular ligation of peptides and proteins (SICLOPPS). Here we detail and discuss the deployment of SICLOPPS libraries for the identification of cyclic peptide inhibitors of a variety of targets. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Towards Optimization of Cyclic Production Systems

    OpenAIRE

    Chauvet, Fabrice; Herrmann, Jeffrey W.; Proth, Jean-Marie

    1999-01-01

    In this paper, the expression "production systems" refers to flow-shops, job-shops, assembly systems, Kanban systems and, in general, to any Discrete Event System (DES) which transforms raw material and/or components into products and/or components. Such a system is said to be cyclic if it provides indefinitely the same sequence of products. A schedule of a cyclic production system is defined as soon as the starting time of each operation on the related resource is known. It has been showed t...

  9. Studies on the effects of ionizing radiation and chemotherapeutic agents on hematopoiesis according to the stem-cell kinetics

    International Nuclear Information System (INIS)

    Hirashima, Kunitake

    1975-01-01

    The fundamental problem of the effects of ionizing radiation and antineoplastic drugs on hematopoiesis can be explained by the kinetic study on the hematopoietic stem-cell population. Quantitative comparison of a single x-irradiation and a single administration of several antineoplastic drugs on the stem-cell population was performed by the splenic colony-forming method. The repopulation pattern of stem-cells in mice after a single 150 rad irradiation was compared with that after the administration of corresponding dose of cyclophosphamide. It was demonstrated that the additional administration of cyclophosphamide immediately after the x-irradiation significantly accelerated repopulation of the stem-cell compartment. The mechanism of repopulation of the stem-cell compartment after partial irradiation was also studied according to the immigration theory of stem-cells. An in vitro colony-forming technique for the human bone marrow cells was introduced and compared with other assay methods for stem-cells. From the hematological observations of accidentally irradiated patients, it was determined that the thromboelastogram values were regarded as one of the most useful indicators for detecting the earliest recovery sign of the hematopoietic stem-cells. (Evans, J.)

  10. Donor hematopoiesis in mice following total lymphoid irradiation requires host T-regulatory cells for durable engraftment

    Science.gov (United States)

    Müller, Antonia M. S.; Poyser, Jessica; Küpper, Natascha J.; Burnett, Cassandra; Ko, Rose M.; Kohrt, Holbrook E.K.; Florek, Mareike; Zhang, Pei; Negrin, Robert S.

    2014-01-01

    Total lymphoid irradiation (TLI) with antithymocyte globulin (ATG) is a unique regimen that prepares recipients for allogeneic hematopoietic cell transplantation by targeting lymph nodes, while sparing large areas of the bone marrow. TLI is reported to increase the frequency of CD4+CD25+FoxP3+ T-regulatory cells (Treg) relative to conventional T cells. In this study, barriers to hematopoietic stem cell (HSC) engraftment following this nonmyeloablative conditioning were evaluated. TLI/ATG resulted in profound lymphoablation but endogenous host HSC remained. Initial donor HSC engraftment occurred only in radiation exposed marrow sites, but gradually distributed to bone marrow outside the radiation field. Sustained donor engraftment required host lymphoid cells insofar as lymphocyte deficient Rag2γc−/− recipients had unstable engraftment compared with wild-type. TLI/ATG treated wild-type recipients had increased proportions of Treg that were associated with increased HSC frequency and proliferation. In contrast, Rag2γc−/− recipients who lacked Treg did not. Adoptive transfer of Treg into Rag2γc−/− recipients resulted in increased cell cycling of endogenous HSC. Thus, we hypothesize that Treg influence donor engraftment post-TLI/ATG by increasing HSC cell cycling, thereby promoting the exit of host HSC from the marrow niche. Our study highlights the unique dynamics of donor hematopoiesis following TLI/ATG, and the effect of Treg on HSC activity. PMID:24591203

  11. Dominance Hierarchies in Young Children

    Science.gov (United States)

    Edelman, Murray S.; Omark, Donald R.

    1973-01-01

    This study uses the ethological approach of seeking species characteristics and phylogenetic continuities in an investigation of human behavior. Among primates a striking consistency is the presence of some form of dominance hierarchy in many species. The present study examines peer group dominance hierarchies as they are perceived by children in…

  12. Dominant Leadership Style in Schools

    Science.gov (United States)

    Rajbhandari, Mani Man Singh

    2006-01-01

    The dominant leadership style is defined by the situation and the kind of organizational environment and climate. This, however, does not sufficiently define the leadership qualities in school organizations. There are other factors which also determine the dominant leadership style, which are the traits and style, teachers commitments, pass out…

  13. Breaking antidunes: Cyclic behavior due to hysteresis

    DEFF Research Database (Denmark)

    Deigaard, Rolf

    2006-01-01

    The cyclic behavior of breaking antidunes (growth, breaking of surface wave, obliteration) is investigated by use of a numerical model. The model includes the transition between supercritical and transcritical flow. As the antidune grows the flow becomes transcritical and a hydraulic jump is form...

  14. Cyclic Plastic Deformation and Welding Simulation

    NARCIS (Netherlands)

    Ten Horn, C.H.L.J.

    2003-01-01

    One of the concerns of a fitness for purpose analysis is the quantification of the relevant material properties. It is known from experiments that the mechanical properties of a material can change due to a monotonic plastic deformation or a cyclic plastic deformation. For a fitness for purpose

  15. Cyclical Variability of Prominences, CMEs and Flares

    Indian Academy of Sciences (India)

    tribpo

    tions of solar activity. For many years, qualitative studies were made about the cyclical behaviour of such phenomena. Nowadays, more quantitative ... phenomenon has been observed in every cycle and is independent of the intensity of the cycle. The characteristic pattern of the polar zone is a "rush to the poles" and the.

  16. Cyclical Variability of Prominences, CMEs and Flares

    Indian Academy of Sciences (India)

    ... Refresher Courses · Symposia · Live Streaming. Home; Journals; Journal of Astrophysics and Astronomy; Volume 21; Issue 3-4. Cyclical Variability of Prominences, CMEs and Flares. J. L. Ballester. Session V – Vector Magnetic Fields, Prominences, CMEs & Flares Volume 21 Issue 3-4 September-December 2000 pp ...

  17. Steady state oxygen reduction and cyclic voltammetry

    DEFF Research Database (Denmark)

    Rossmeisl, Jan; Karlberg, Gustav; Jaramillo, Thomas

    2008-01-01

    The catalytic activity of Pt and Pt3Ni for the oxygen reduction reaction is investigated by applying a Sabatier model based on density functional calculations. We investigate the role of adsorbed OH on the activity, by comparing cyclic voltammetry obtained from theory with previously published...

  18. Cyclic Cratonic Carbonates and Phanerozoic Calcite Seas.

    Science.gov (United States)

    Wilkinson, Bruce H.

    1982-01-01

    Discusses causes of cyclicity in cratonic carbonate sequences and evidence for and potential significance of postulated primary calcite sediment components in past Paleozoic seas, outlining problems, focusing on models explaining existing data, and identifying background. Future sedimentary geologists will need to address these and related areas…

  19. Cyclic olefin copolymer-silica nanocomposites foams

    Czech Academy of Sciences Publication Activity Database

    Pegoretti, A.; Dorigato, A.; Biani, A.; Šlouf, Miroslav

    2016-01-01

    Roč. 51, č. 8 (2016), s. 3907-3916 ISSN 0022-2461 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : cyclic olefin copolymer * nanocomposites * silica Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.599, year: 2016

  20. A Note on Isolate Domination

    OpenAIRE

    Sahul Hamid, Ismail; Balamurugan, S; Navaneethakrishnan, A

    2016-01-01

    A set $S$ of vertices of a graph $G$ such that $\\left\\langle S\\right\\rangle$ has an isolated vertex is called an \\emph{isolate set} of $G$. The minimum and maximum cardinality of a maximal isolate set are called the \\emph{isolate number} $i_0(G)$ and the \\emph{upper isolate number} $I_0(G)$ respectively. An isolate set that is also a dominating set (an irredundant set) is an $\\emph{isolate dominating set} \\ (\\emph{an isolate irredundant set})$. The \\emph{isolate domination number} $\\gamma_0(G...

  1. Domination criticality in product graphs

    Directory of Open Access Journals (Sweden)

    M.R. Chithra

    2015-07-01

    Full Text Available A connected dominating set is an important notion and has many applications in routing and management of networks. Graph products have turned out to be a good model of interconnection networks. This motivated us to study the Cartesian product of graphs G with connected domination number, γc(G=2,3 and characterize such graphs. Also, we characterize the k−γ-vertex (edge critical graphs and k−γc-vertex (edge critical graphs for k=2,3 where γ denotes the domination number of G. We also discuss the vertex criticality in grids.

  2. Dominantly inherited cystoid macular edema.

    Science.gov (United States)

    Fishman, G A; Goldberg, M F; Trautmann, J C

    1979-01-01

    Four patients of Greek ancestry had dominantly inherited cystoid macular edema. Characteristics of this syndrome include the following: an early onset and prolonged course of cystoid changes in the macula, followed by atrophy of the macula in later stages. Some patients also show leakage of fluorescein from the optic disc capillaries, subnormal EOG Lp/Dt ratios, elevated rod dark adaptation thresholds, red-green and blue-yellow color deficiencies, normal ERG findings, hyperopia, peripheral pigmentary retinopathy, and vitreous opacities. Dominantly inherited cystoid macular edema is a distinct genetic trait among the dominantly inherited macular dystrophies.

  3. Effects of hypokinesia on cyclic nucleotides and hormonal regulation ...

    African Journals Online (AJOL)

    PTH), calcitonin (CT), cyclic nucleotides (cAMP, cGMP) and calcium in the blood of rats, while in urine - phosphate, calcium and cyclic nucleotides. Design: Laboratory based experiment. Setting: Laboratory in the Department of Biochemistry, ...

  4. Augmentation Quotients for Real Representation Rings of Cyclic ...

    Indian Academy of Sciences (India)

    29

    Augmentation Quotients for Real Representation Rings of Cyclic Groups. Article Type: Reseach Article. Keywords: cyclic group; real representation; augmentation ideal; augmentation quotient. Corresponding Author: Hang Liu, Ph.D. Shaanxi Normal University. Xi'an, Shaanxi CHINA. Corresponding Author Secondary.

  5. Compressed sensing with cyclic-S Hadamard matrix for terahertz imaging applications

    Science.gov (United States)

    Ermeydan, Esra Şengün; ćankaya, Ilyas

    2018-01-01

    Compressed Sensing (CS) with Cyclic-S Hadamard matrix is proposed for single pixel imaging applications in this study. In single pixel imaging scheme, N = r . c samples should be taken for r×c pixel image where . denotes multiplication. CS is a popular technique claiming that the sparse signals can be reconstructed with samples under Nyquist rate. Therefore to solve the slow data acquisition problem in Terahertz (THz) single pixel imaging, CS is a good candidate. However, changing mask for each measurement is a challenging problem since there is no commercial Spatial Light Modulators (SLM) for THz band yet, therefore circular masks are suggested so that for each measurement one or two column shifting will be enough to change the mask. The CS masks are designed using cyclic-S matrices based on Hadamard transform for 9 × 7 and 15 × 17 pixel images within the framework of this study. The %50 compressed images are reconstructed using total variation based TVAL3 algorithm. Matlab simulations demonstrates that cyclic-S matrices can be used for single pixel imaging based on CS. The circular masks have the advantage to reduce the mechanical SLMs to a single sliding strip, whereas the CS helps to reduce acquisition time and energy since it allows to reconstruct the image from fewer samples.

  6. Social Dominance and Sexual Orientation

    OpenAIRE

    Dickins, Thomas E.; Sergeant, Mark J.T.

    2008-01-01

    Heterosexual males are reported to display higher levels of physical aggression and lower levels of empathy than homosexual males. A characteristic linked to both aggression and empathy is social dominance orientation (SDO). A significant sex difference has been reported for SDO, with heterosexual males scoring higher than heterosexual females. The precise relationship between dominance and aggression is currently contested. Given the association between SDO, aggression and empathy, and the d...

  7. A note on isolate domination

    Directory of Open Access Journals (Sweden)

    Ismail Sahul Hamid

    2016-04-01

    Full Text Available A set $S$ of vertices of a graph $G$ such that $\\left\\langle S\\right\\rangle$ has an isolated vertex is called an \\emph{isolate set} of $G$. The minimum and maximum cardinality of a maximal isolate set are called the \\emph{isolate number} $i_0(G$ and the \\emph{upper isolate number} $I_0(G$ respectively. An isolate set that is also a dominating set (an irredundant set is an $\\emph{isolate dominating set} \\ (\\emph{an isolate irredundant set}$. The \\emph{isolate domination number} $\\gamma_0(G$ and the \\emph{upper isolate domination number} $\\Gamma_0(G$ are respectively the minimum and maximum cardinality of a minimal isolate dominating set while the \\emph{isolate irredundance number} $ir_0(G$ and the \\emph{upper isolate irredundance number} $IR_0(G$ are the minimum and maximum cardinality of a maximal isolate irredundant set of $G$. The notion of isolate domination was introduced in \\cite{sb} and the remaining were introduced in \\cite{isrn}. This paper further extends a study of these parameters.   

  8. Cyclic Soft Groups and Their Applications on Groups

    Directory of Open Access Journals (Sweden)

    Hacı Aktaş

    2014-01-01

    Full Text Available In crisp environment the notions of order of group and cyclic group are well known due to many applications. In this paper, we introduce order of the soft groups, power of the soft sets, power of the soft groups, and cyclic soft group on a group. We also investigate the relationship between cyclic soft groups and classical groups.

  9. The effects of hematopoietic stem cell transplant on splenic extramedullary hematopoiesis in patients with myeloproliferative neoplasm-associated myelofibrosis.

    Science.gov (United States)

    Pizzi, Marco; Gergis, Usama; Chaviano, Felicia; Orazi, Attilio

    2016-09-01

    Hematopoietic stem cell transplant (HSCT) is the only curative treatment for myeloproliferative neoplasm-associated myelofibrosis (MPN-MF). The main clinical manifestation of MPN-MF is splenomegaly secondary to extramedullary hematopoiesis (EMH). The effects of HSCT on splenic EMH and associated vascular and stromal changes are unknown. This study compares the findings seen in spleens following HSCT with those of nontransplanted patients, normal controls, and matched bone marrow (BM) samples. This study included three transplanted MPN-MF spleens, three nontransplanted MPN-MF spleens, and three normal controls. Spleens were assessed for: (a) presence/extent of EMH; (b) presence of Gamna-Gandy bodies; (c) splenic fibrosis; (d) CD34-positive microvessel density; (e) CD8-positive sinusoids; (f) frequency of smooth muscle actin-positive myoid cells; and (g) nerve growth factor receptor-positive adventitial reticulum cells. In two cases, matched BM samples were assessed for cellularity, presence of atypical megakaryocytes, and fibrosis. Compared with normal controls, all MPN-MF spleens were larger in size, had EMH, red pulp fibrosis, higher CD34-positive microvessel density, and decreased CD8-positive sinusoids. Compared with nontransplanted cases, post-HSCT spleens showed disappearance or reduction of EMH. Gamna-Gandy bodies were increased; no differences in the remaining parameters were found. A reduction of splenic EMH was associated with normalization of BM cellularity and megakaryopoiesis. HSCT reduces/abrogates splenic EMH and is associated with an increased number of Gamna-Gandy bodies, which may suggest vascular damage. The lack of stromal changes in spleens removed shortly after transplant is in line with similar observations in the BM, where a longer interval is often necessary for resolution of fibrosis. Copyright © 2016 King Faisal Specialist Hospital & Research Centre. Published by Elsevier Ltd. All rights reserved.

  10. Fast decline of hematopoiesis and uncoupling protein 2 content in human liver after birth: location of the protein in Kupffer cells

    Czech Academy of Sciences Publication Activity Database

    Brauner, Petr; Nibbelink, M.; Flachs, P.; Vítková, I.; Kopecký, P.; Mertelíková, Irena; Janderová, L.; Pénicaud, L.; Casteilla, L.; Plavka, R.; Kopecký, Jan

    2001-01-01

    Roč. 49, č. 3 (2001), s. 440-447 ISSN 0031-3998 R&D Projects: GA MŠk LN00A079; GA MZd NE4643 Grant - others:Dvoustranná česko-francouzská spolupráce v oblasti vědy a výzkumu(XE) Barrande 98082-2 Institutional research plan: CEZ:AV0Z5011922 Keywords : hepatic hematopoiesis * uncoupling protein 2 Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 3.289, year: 2001

  11. Beta1 integrin is not essential for hematopoiesis but is necessary for the T cell-dependent IgM antibody response

    DEFF Research Database (Denmark)

    Brakebusch, Cord; Fillatreau, Simon; Potocnik, Alexandre J

    2002-01-01

    Several experimental evidences suggested that beta1 integrin-mediated adhesion of hematopoietic stem cells (HSC) is important for their function in the bone marrow (BM). Using induced deletion of the beta1 integrin gene restricted to the hematopoietic system, we show that beta1 integrin...... is not essential for HSC retention in the BM, hematopoiesis, and trafficking of lymphocytes. However, immunization with a T cell-dependent antigen resulted in virtually no IgM production and an increased secretion of IgG in mutant mice, while the response to a T cell-independent type 2 antigen showed decreases...

  12. Strain gradient effects on cyclic plasticity

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Legarth, Brian Nyvang

    2010-01-01

    Size effects on the cyclic shear response are studied numerically using a recent higher order strain gradient visco-plasticity theory accounting for both dissipative and energetic gradient hardening. Numerical investigations of the response under cyclic pure shear and shear of a finite slab between...... rigid platens have been carried out, using the finite element method. It is shown for elastic–perfectly plastic solids how dissipative gradient effects lead to increased yield strength, whereas energetic gradient contributions lead to increased hardening as well as a Bauschinger effect. For linearly...... hardening materials it is quantified how dissipative and energetic gradient effects promote hardening above that of conventional predictions. Usually, increased hardening is attributed to energetic gradient effects, but here it is found that also dissipative gradient effects lead to additional hardening...

  13. A cyclic symmetry principle in physics

    International Nuclear Information System (INIS)

    Green, H.S.; Adelaide Univ., SA

    1994-01-01

    Many areas of modern physics are illuminated by the application of a symmetry principle, requiring the invariance of the relevant laws of physics under a group of transformations. This paper examines the implications and some of the applications of the principle of cyclic symmetry, especially in the areas of statistical mechanics and quantum mechanics, including quantized field theory. This principle requires invariance under the transformations of a finite group, which may be a Sylow π-group, a group of Lie type, or a symmetric group. The utility of the principle of cyclic invariance is demonstrated in finding solutions of the Yang-Baxter equation that include and generalize known solutions. It is shown that the Sylow π-groups have other uses, in providing a basis for a type of generalized quantum statistics, and in parametrising a new generalization of Lie groups, with associated algebras that include quantized algebras. 31 refs

  14. Analysis of cyclic creep and rupture. Part 1: bounding theorems and cyclic reference stresses

    Energy Technology Data Exchange (ETDEWEB)

    Carter, P. [Stress Engineering Services, Inc., Mason, OH 45040 (United States)]. E-mail: peter.carter@ses-oh.com

    2005-01-01

    Cyclic loading on structures can produce failures not readily predicted by conventional static analysis. Ratcheting or incremental distortion leads to structural failure, and complicates the problems of creep and fatigue prediction. Predicting shakedown, ratcheting, accelerated creep and rupture, for cyclic loading, are the objectives of cyclic stress analysis.Limit load, shakedown and ratcheting analyses provide a comprehensive basis to understand static structural behaviour for ductile inelastic materials, subject to variable loading but excluding inertial dynamic effects. From them we can predict the following failure modes:-Plastic collapse.-Failure to shakedown.-Ratcheting.-Accelerated creep and rupture.This is achieved with a generalisation of the reference stress concept. Conventionally, and for steady loading, the limit load reference stress is the lowest yield stress for which the structure does not collapse. For cyclic loading two definitions are available. The more conservative is the lowest yield stress for which the structure shakes down (behaves elastically). The less conservative is the lowest yield stress for which the structure does not ratchet. They have different meanings and uses.Explaining and justifying the use of cyclic reference stresses to bound creep and rupture is the objective of Part 1. Part 2 gives examples illustrating a range of structural behaviours. The methodology of these papers involves so-called approximate methods at one level, that of inferring limiting or conservative time-dependent behaviour from time-independent elastic-plastic cyclic analyses. The elastic-plastic cyclic analyses themselves are straightforward if tedious. Some ideas and a new analysis technique are available to reduce the trial-and-error.

  15. Numerically investigating the emergent cyclic inflation scenario

    International Nuclear Information System (INIS)

    Duhe, William; Biswas, Tirthabir

    2014-01-01

    We provide a comprehensive numerical study of the emergent cyclic inflation scenario. This is a scenario where instead of traditional monotonic slow roll inflation, the universe expands over numerous short asymmetric cycles due to the production of entropy via interactions among different species. This is one of the very few scenarios of inflation that provides a non-singular geodesically complete space-time and does not require any ‘reheating’ mechanism. (paper)

  16. Scale factor duality for conformal cyclic cosmologies

    International Nuclear Information System (INIS)

    Silva, University Camara da; Lima, A.L. Alves; Sotkov, G.M.

    2016-01-01

    The scale factor duality is a symmetry of dilaton gravity which is known to lead to pre-big-bang cosmologies. A conformal time version of the scale factor duality (SFD) was recently implemented as a UV/IR symmetry between decelerated and accelerated phases of the post-big-bang evolution within Einstein gravity coupled to a scalar field. The problem investigated in the present paper concerns the employment of the conformal time SFD methods to the construction of pre-big-bang and cyclic extensions of these models. We demonstrate that each big-bang model gives rise to two qualitatively different pre-big-bang evolutions: a contraction/expansion SFD model and Penrose’s Conformal Cyclic Cosmology (CCC). A few examples of SFD symmetric cyclic universes involving certain gauged Kähler sigma models minimally coupled to Einstein gravity are studied. We also describe the specific SFD features of the thermodynamics and the conditions for validity of the generalized second law in the case of Gauss-Bonnet (GB) extension of these selected CCC models.

  17. Visualization of cyclic nucleotide dynamics in neurons

    Directory of Open Access Journals (Sweden)

    Kirill eGorshkov

    2014-12-01

    Full Text Available The second messengers cAMP and cGMP transduce many neuromodulatory signals from hormones and neurotransmitters into specific functional outputs. Their production, degradation and signaling are spatiotemporally regulated to achieve high specificity in signal transduction. The development of genetically encodable fluorescent biosensors has provided researchers with useful tools to study these versatile second messengers and their downstream effectors with unparalleled spatial and temporal resolution in cultured cells and living animals. In this review, we introduce the general design of these fluorescent biosensors and describe several of them in more detail. Then we discuss a few examples of using cyclic nucleotide fluorescent biosensors to study regulation of neuronal function and finish with a discussion of advances in the field. Although there has been significant progress made in understanding how the specific signaling of cyclic nucleotide second messengers is achieved, the mechanistic details in complex cell types like neurons are only just beginning to surface. Current and future fluorescent protein reporters will be essential to elucidate the role of cyclic nucleotide signaling dynamics in the functions of individual neurons and their networks.

  18. Extramedullary pulmonary hematopoiesis causing pulmonary hypertension and severe tricuspid regurgitation detected by 99m technetium sulfur colloid bone marrow scan and single-photon emission computed tomography/CT

    International Nuclear Information System (INIS)

    Ali, Syed Zama; Clarke, Michael John; Kannivelu, Anbalagan; Chinchure, Dinesh; Srinivasan, Sivasubramanian

    2014-01-01

    Extramedullary pulmonary hematopoiesis is a rare entity with a limited number of case reports in the available literature only. We report the case of a 66-year-old man with known primary myelofibrosis, in whom a 99m technetium sulfur colloid bone marrow scan with single-photon emission computed tomography (SPECT)/CT revealed a pulmonary hematopoiesis as the cause of pulmonary hypertension and severe tricuspid regurgitation. To the best of our knowledge, this is the first description of 99m technetium sulfur colloid SPECT/CT imaging in this rare condition.

  19. Extramedullary pulmonary hematopoiesis causing pulmonary hypertension and severe tricuspid regurgitation detected by {sup 99m} technetium sulfur colloid bone marrow scan and single-photon emission computed tomography/CT

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Syed Zama; Clarke, Michael John; Kannivelu, Anbalagan; Chinchure, Dinesh; Srinivasan, Sivasubramanian [Dept. of Diagnostic Radiology, Khoo Teck Puat Hospital, Singapore (Singapore)

    2014-06-15

    Extramedullary pulmonary hematopoiesis is a rare entity with a limited number of case reports in the available literature only. We report the case of a 66-year-old man with known primary myelofibrosis, in whom a {sup 99m}technetium sulfur colloid bone marrow scan with single-photon emission computed tomography (SPECT)/CT revealed a pulmonary hematopoiesis as the cause of pulmonary hypertension and severe tricuspid regurgitation. To the best of our knowledge, this is the first description of {sup 99m} technetium sulfur colloid SPECT/CT imaging in this rare condition.

  20. Highly dominating, highly authoritarian personalities.

    Science.gov (United States)

    Altemeyer, Bob

    2004-08-01

    The author considered the small part of the population whose members score highly on both the Social Dominance Orientation scale and the Right-Wing Authoritarianism scale. Studies of these High SDO-High RWAs, culled from samples of nearly 4000 Canadian university students and over 2600 of their parents and reported in the present article, reveal that these dominating authoritarians are among the most prejudiced persons in society. Furthermore, they seem to combine the worst elements of each kind of personality, being power-hungry, unsupportive of equality, manipulative, and amoral, as social dominators are in general, while also being religiously ethnocentric and dogmatic, as right-wing authoritarians tend to be. The author suggested that, although they are small in number, such persons can have considerable impact on society because they are well-positioned to become the leaders of prejudiced right-wing political movements.

  1. Multiaxial elastoplastic cyclic loading of austenitic 316L steel

    Directory of Open Access Journals (Sweden)

    V. Mazánová

    2017-04-01

    Full Text Available Cyclic stress-strain response and fatigue damage character has been investigated in austenitic stainless steel 316L. Hollow cylindrical specimens have been cyclically deformed in combined tension-compression and torsion under constant strain rate condition and different constant strain and shear strain amplitudes. In-phase and 90° out-of-phase cyclic straining was applied and the stress response has been monitored. Cyclic hardening/softening curves were assessed in both channels. Cyclic softening followed for higher strain amplitudes by long-term cyclic hardening was observed. Cyclic stress-strain curves were determined. Study of the surface damage in fractured specimens revealed the types and directions of principal cracks and the sources of fatigue crack initiation in slip bands.

  2. Mechanical stability of the diamond-like carbon film on nitinol vascular stents under cyclic loading

    International Nuclear Information System (INIS)

    Kim, Hyun-Jong; Moon, Myoung-Woon; Lee, Kwang-Ryeol; Seok, Hyun-Kwang; Han, Seung-Hee; Ryu, Jae-Woo; Shin, Kyong-Min; Oh, Kyu Hwan

    2008-01-01

    The mechanical stability of diamond-like carbon (DLC) films coated on nitinol vascular stents was investigated under cyclic loading condition by employing a stent crimping system. DLC films were coated on the vascular stent of a three dimensional structure by using a hybrid ion beam system with rotating jig. The cracking or delamination of the DLC coating occurred dominantly near the hinge connecting the V-shaped segments of the stent where the maximum strain was induced by a cyclic loading of contraction and extension. However the failures were significantly suppressed as the amorphous Si (a-Si) buffer layer thickness increased. Interfacial adhesion strength was estimated from the spalled crack size in the DLC coating for various values of the a-Si buffer layer thickness

  3. Visual dominance in olfactory memory.

    Science.gov (United States)

    Batic, N; Gabassi, P G

    1987-08-01

    The object of the present study was to verify the emergence of a 'visual dominance' effect in memory tests involving different sensory modes (sight and smell), brought about the preattentive mechanisms which select the visual sensory mode regardless of the recall task.

  4. Vector-meson dominance revisited

    Directory of Open Access Journals (Sweden)

    Terschlüsen Carla

    2012-12-01

    Full Text Available The interaction of mesons with electromagnetism is often well described by the concept of vector-meson dominance (VMD. However, there are also examples where VMD fails. A simple chiral Lagrangian for pions, rho and omega mesons is presented which can account for the respective agreement and disagreement between VMD and phenomenology in the sector of light mesons.

  5. Hand dominance in orthopaedic surgeons.

    LENUS (Irish Health Repository)

    Lui, Darren F

    2012-08-01

    Handedness is perhaps the most studied human asymmetry. Laterality is the preference shown for one side and it has been studied in many aspects of medicine. Studies have shown that some orthopaedic procedures had poorer outcomes and identified laterality as a contributing factor. We developed a questionnaire to assess laterality in orthopaedic surgery and compared this to an established scoring system. Sixty-two orthopaedic surgeons surveyed with the validated Waterloo Handedness Questionnaire (WHQ) were compared with the self developed Orthopaedic Handedness Questionnaire (OHQ). Fifty-eight were found to be right hand dominant (RHD) and 4 left hand dominant (LHD). In RHD surgeons, the average WHQ score was 44.9% and OHQ 15%. For LHD surgeons the WHQ score was 30.2% and OHQ 9.4%. This represents a significant amount of time using the non dominant hand but does not necessarily determine satisfactory or successful dexterity transferable to the operating room. Training may be required for the non dominant side.

  6. Testing for Stochastic Dominance Efficiency

    NARCIS (Netherlands)

    G.T. Post (Thierry); O. Linton; Y-J. Whang

    2005-01-01

    textabstractWe propose a new test of the stochastic dominance efficiency of a given portfolio over a class of portfolios. We establish its null and alternative asymptotic properties, and define a method for consistently estimating critical values. We present some numerical evidence that our

  7. The hematopoiesis in gill and its role in the immune response of Pacific oyster Crassostrea gigas against secondary challenge with Vibrio splendidus.

    Science.gov (United States)

    Li, Yiqun; Song, Xiaorui; Wang, Weilin; Wang, Lingling; Yi, Qilin; Jiang, Shuai; Jia, Zhihao; Du, Xinyu; Qiu, Limei; Song, Linsheng

    2017-06-01

    Increasing evidences have demonstrated that the invertebrate gill is a predominant tissue participating in the immune response during pathogen challenge. In the present study, the hematopoiesis and immune activities in gill of Pacific oyster Crassostrea gigas were investigated. Stem-like cells with big nuclei and thin cytoplasm were found in the tubules of gill filaments, where DNA synthesis is active and hemocytes production are exuberant. The oysters primarily stimulated by formaldehyde-killed Vibrio splendidus exhibited stronger immune responses and enhanced cell regeneration in gill when they encountered the secondary challenge of live V. splendidus. After the secondary stimulation with V. splendidus, the expression levels of CgClec-4 and CgIFN in the gill of oysters pre-stimulated with formaldehyde-killed V. splendidus were significantly higher (p immune-related protein CgEcSOD in gill increased apparently after the secondary challenge with V. splendidus. ROS production was also enhanced (p response than that pre-stimulated with filter-sterilized sea water. These results collectively showed that the immune parameters in gill were apparently enhanced after secondary challenge with live V. splendidus, indicating that hematopoiesis might participate in immune priming in Pacific oyster C. gigas. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. A giant cord hemangioma with extramedullary hematopoiesis and elevated maternal serum human chorionic gonadotropin: a case report and review of the literature.

    Science.gov (United States)

    Hara, Kieko; Fukumura, Yuki; Saito, Tsuyoshi; Arakawa, Atsushi; Okabe, Hitomi; Takeda, Satoru; Yao, Takashi

    2015-09-04

    A case of prenatally diagnosed, giant cord hemangioma is reported, which was accompanied by the elevation of maternal serum alpha-fetoprotein (MS-AFP) and human chorionic gonadotropin (MS-hCG) levels. A 30-year-old woman without a previous history of gravida or para, presented with intermittent abdominal pain at 26 weeks of gestation. Doppler studies showed the fetus developing heart failure as the tumor grew larger. Caesarian section was performed at 29 weeks of gestation. Macroscopic examination of the placenta revealed a 17.0 × 10.0 × 7.0 cm tumor localized at the placental end of the umbilical cord. Microscopically, the tumor was composed of small arborizing vessels proliferating in the myxoid background, and the tumor cells were positive for AFP by immunohistochemistry. Extramedullary hematopoiesis was seen in the tumor vascular channels. The present case is one of the largest umbilical cord hemangiomas reported in the literature, and the first hemangioma case with MS-hCG elevation, extramedullary hematopoiesis, and positive AFP staining in the cord hemangioma. Its clinical course and detailed pathological findings are presented along with a review of the related literature.

  9. The new face of the old molecules: crustin Pm4 and transglutaminase type I serving as rnps down-regulate astakine-mediated hematopoiesis.

    Directory of Open Access Journals (Sweden)

    Yun-Tsan Chang

    Full Text Available Astakine is an important cytokine that is involved in crustacean hematopoiesis. Interestingly, the protein levels of astakine increased dramatically in plasma of LPS-injected shrimp while mRNA levels remained unchanged. Here, we investigated the involvement of astakine 3'-untranslated region (UTR in its protein expression. The 3'-UTR of astakine down-regulated the expression of reporter protein but the mRNA stability of reporter gene was unaffected. We identified the functional regulatory elements of astakine 3'-UTR, where 3'-UTR242-483 acted as repressor. The electrophoresis mobility shift assay (EMSA, RNA pull-down assay and LC/MS/MS were performed to identify the protein association. We noted that crustin Pm4 and shrimp transglutaminase I (STG I were associated to astakine 3'-UTR242-483, while two other proteins have yet to be revealed. Depletion of hemocytic crustin Pm4 and STG I significantly increased the protein level of astakine while astakine mRNA level remained unaffected. Lipopolysaccharide (LPS stimulated the secretion of crustin Pm4 and STG I from hemocytes to plasma and increased the astakine level to stimulate the hemocytes proliferation. Altogether, we identified the shrimp crustin Pm4 and STG I as novel RNA binding proteins that play an important role in down-regulating astakine expression at post-transcriptional level and are crucial for the maintenance of hematopoiesis.

  10. Stromal cell-associated hematopoiesis: immortalization and characterization of a primate bone marrow-derived stromal cell line.

    Science.gov (United States)

    Paul, S R; Yang, Y C; Donahue, R E; Goldring, S; Williams, D A

    1991-04-15

    An elucidation of the interaction between the bone marrow microenvironment and hematopoietic stem cells is critical to the understanding of the molecular basis of stem cell self renewal and differentiation. This interaction is dependent, at least in part, on direct cell to cell contact or cellular adhesion to extracellular matrix proteins. Long-term bone marrow cultures (LTMC) provide an appropriate microenvironment for maintenance of primitive hematopoietic stem cells and a means of analyzing this stem cell-stromal cell interaction in vitro. Although LTMC have been successfully generated from murine and human bone marrow, only limited success has been reported in a primate system. In addition, few permanent stromal cell lines are available from nonmurine bone marrow. Because the primate has become a useful model for large animal bone marrow transplant studies and, more specifically, retroviral-mediated gene transfer analysis, we have generated immortalized bone marrow stromal cell lines from primate bone marrow using gene transfer of the Simian virus large T (SV40 LT) antigen. At least one stromal cell line has demonstrated the capacity to maintain early hematopoietic cells in long-term cultures for up to 4 weeks as measured by in vitro progenitor assays. Studies were undertaken to characterize the products of extracellular matrix biosynthesis and growth factor synthesis of this cell line, designated PU-34. In contrast to most murine bone marrow-derived stromal cell lines capable of supporting hematopoiesis in vitro that have been examined, the extracellular matrix produced by this primate cell line includes collagen types I, laminin. Growth factor production analyzed through RNA blot analysis, bone marrow cell culture data, and factor-dependent cell line proliferation assays includes interleukin-6 (IL-6), IL-7, granulocyte-macrophage colony-stimulating factor (GM-CSF), G-CSF, M-CSF, leukemia inhibitory factor, and a novel cytokine designated IL-11. This

  11. Biological hydrogen production in an anaerobic sequencing batch reactor: pH and cyclic duration effects

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wen-Hsing [Department of Environmental Engineering, National Ilan University, I-Lan 260 (China); Sung, Shihwu [Department of Civil, Construction and Environmental Engineering, Iowa State University, Ames, Iowa 50011-3232 (United States); Chen, Shen-Yi [Department of Safety, Health and Environmental Engineering, National Kaohsiung First University of Science and Technology, Kaohsiung 811 (China)

    2009-01-15

    An anaerobic sequencing batch reactor (ASBR) was used to evaluate biological hydrogen production from carbohydrate-rich organic wastes. The goal of the proposed project was to investigate the effects of pH (4.9, 5.5, 6.1, and 6.7), and cyclic duration (4, 6, and 8 h) on hydrogen production. With the ASBR operated at 16-h HRT, 25 g COD/L, and 4-h cyclic duration, the results showed that the maximum hydrogen yield of 2.53 mol H{sub 2}/mol sucrose{sub consumed} appeared at pH 4.9. The carbohydrate removal efficiency declined to 56% at pH 4.9, which indirectly resulted in the reduction of total volatile fatty acid production. Acetate fermentation was the dominant metabolic pathway at pH 4.9. The concentration of mixed liquor volatile suspended solid (MLVSS) also showed a decrease from nearly 15,000 mg/L between pHs 6.1 and 6.7 to 6000 mg/L at pH 4.9. Investigation of the effect of cyclic duration found that hydrogen yield reached the maximum of 1.86 mol H{sub 2}/mol sucrose{sub consumed} at 4-h cyclic duration while ASBR was operating at 16-h HRT, 15 g COD/L, and pH 4.9. The experimental results showed that MLVSS concentration increased from 6200 mg/L at 4-h cyclic duration to 8500 mg/L at 8-h cyclic duration. However, there was no significant change in effluent volatile suspended solid concentration. The results of butyrate to acetate ratio showed that using this ratio to correlate the performance of hydrogen production is not appropriate due to the growth of homoacetogens. In ASBR, the operation is subject to four different phases of each cycle, and only the complete mix condition can be achieved at react phase. The pH and cyclic duration under the unique operations profoundly impact fermentative hydrogen production. (author)

  12. Nitration Study of Cyclic Ladder Polyphenylsilsesquioxane

    Directory of Open Access Journals (Sweden)

    LIANG Jia-xiang

    2017-05-01

    Full Text Available Several nitration reagents including fuming nitric acid, HNO3-H2SO4, KNO3-H2SO4, HNO3-KNO3, CH3COOH-KNO3, (CH3CO2O-HNO3 were used to nitrate cyclic ladder polyphenylsilsesquioxane (CL-PPSQ in different conditions in order to enhance the compatibility of the CL-PPSQ in polymers, the NO2-PPSQ was obtained. FTIR, element analysis, GPC, TGA and 1H NMR were used to characterize the structures of the nitrated products. The results show that the nitrating abilities of the fuming nitric acid, HNO3-H2SO4 and KNO3-H2SO4 are very strong. Many nitro groups can be linked with phenyl groups in CL-PPSQ, but with low molecular mass, fracture occurs in siloxane segment. However, the Mn of the product NO2-PPSQ sharply drops by 50% compared with that of CL-PPSQ, so the nitration reagents can break the cyclic structure of CL-PPSQ. The nitrating reagents of HNO3-KNO3 and CH3COOH-KNO3 have no nitration effects on CL-PPSQ. At last, NO2-CL-PPSQ was prepared using (CH3CO2O-HNO3 because of the moderate nitration process and ability. The cyclic structure of PPSQ is remained, although the number of —NO2 group is not too much. At the same time, the nitration mechanism using different nitration reagents was analyzed. A certain amount of NO2+, which is a kind of activator owning strong nitration ability, can be found in the fuming nitric acid and H2SO4-HNO3(KNO3 systems. As to the (CH3CO2O-HNO3 system, the main activator is CH3COONO2.

  13. From nature-dominated to human-dominated environmental changes

    Science.gov (United States)

    Messerli, Bruno; Grosjean, Martin; Hofer, Thomas; Núñez, Lautaro; Pfister, Christian

    2000-01-01

    To what extent is it realistic and useful to view human history as a sequence of changes from highly vulnerable societies of hunters and gatherers through periods with less vulnerable, well buffered and highly productive agrarian-urban societies to a world with regions of extreme overpopulation and overuse of life support systems, so that vulnerability to climatic-environmental changes and extreme events is again increasing? This question cannot be fully answered in our present state of knowledge, but at least we can try to illustrate, with three case studies from different continents, time periods and ecosystems, some fundamental changes in the relationship between natural processes and human activities that occur, as we pass from a nature-dominated to a human dominated environment. 1. Early-mid Holocene: Nature dominated environment — human adaptation, mitigation, and migration. In the central Andes, the Holocene climate changed from humid (10,800-8000 BP) to extreme arid (8000-3600 BP) conditions. Over the same period, prehistoric hunting communities adopted a more sedentary pattern of resource use by settling close to the few perennial water bodies, where they began the process of domesticating camelids around 5000 BP and irrigation from about 3100 BP. 2. Historical period: An agrarian society in transition from an "enduring" to an innovative human response. Detailed documentary evidence from Western Europe may be used to reconstruct quite precisely the impacts of climatic variations on agrarian societies. The period considered spans a major transition from an apparently passive response to the vagaries of the environment during the 16th century to an active and innovative attitude from the onset of the agrarian revolution in the late 18th century through to the present day. The associated changes in technology and in agricultural practices helped to create a society better able to survive the impact of climatic extremes. 3. The present day: A human dominated

  14. Influence of Hold Time and Stress Ratio on Cyclic Creep Properties Under Controlled Tension Loading Cycles of Grade 91 Steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Woo Gon; Park, Jae Young; Jang, Jin Sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Ekaputra, I Made Wicaksana; Kim, Seon Jin [Pukyong National University, Busan (Korea, Republic of)

    2017-04-15

    Influences of hold time and stress ratio on cyclic creep properties of Grade 91 steel were systemically investigated using a wide range of cyclic creep tests, which were performed with hold times (HTs) of 1 minute, 3 minutes, 5 minutes, 10 minutes, 20 minutes, and 30 minutes and stress ratios (R) of 0.5, 0.8, 0.85, 0.90, and 0.95 under tension loading cycles at 600°C. Under the influence of HT, the rupture time increased to HT = 5 minutes at R = 0.90 and R = 0.95, but there was no influence at R = 0.50, 0.80, and 0.85. The creep rate was constant regardless of an increase in the HT, except for the case of HT = 5 minutes at R = 0.90 and R = 0.95. Under the influence of stress ratio, the rupture time increased with an increase in the stress ratio, but the creep rate decreased. The cyclic creep led to a reduction in the rupture time and an acceleration in the creep rate compared with the case of monotonic creep. Cyclic creep was found to depend dominantly on the stress ratio rather than on the HT. Fracture surfaces displayed transgranular fractures resulting from microvoid coalescence, and the amount of microvoids increased with an increase in the stress ratio. Enhanced coarsening of the precipitates in the cyclic creep test specimens was found under all conditions.

  15. Cosmological D-instantons and cyclic universes

    International Nuclear Information System (INIS)

    Bergshoeff, E A; Collinucci, A; Roest, D; Russo, J G; Townsend, P K

    2005-01-01

    For models of gravity coupled to hyperbolic sigma models, such as the metric-scalar sector of IIB supergravity, we show how smooth trajectories in the 'augmented target space' connect FLRW cosmologies to non-extremal D-instantons through a cosmological singularity. In particular, we find closed cyclic universes that undergo an endless sequence of big-bang to big-crunch cycles separated by instanton 'phases'. We also find 'big-bounce' universes in which a collapsing closed universe bounces off its cosmological singularity to become an open expanding universe

  16. Numerical Simulation of Cyclic Thermodynamic Processes

    DEFF Research Database (Denmark)

    Andersen, Stig Kildegård

    2006-01-01

    This thesis is on numerical simulation of cyclic thermodynamic processes. A modelling approach and a method for finding periodic steady state solutions are described. Examples of applications are given in the form of four research papers. Stirling machines and pulse tube coolers are introduced......, compressible flow in one space dimension is presented. The implementation produces models where all the equations, which are on a form that should be understandable to someone with a background in engineering thermodynamics, can be accessed and modified individually. The implementation was designed to make...

  17. Connected domination stable graphs upon edge addition ...

    African Journals Online (AJOL)

    A set S of vertices in a graph G is a connected dominating set of G if S dominates G and the subgraph induced by S is connected. We study the graphs for which adding any edge does not change the connected domination number. Keywords: Connected domination, connected domination stable, edge addition ...

  18. On dominator colorings in graphs

    Indian Academy of Sciences (India)

    Graph coloring and domination are two major areas in graph theory that have been ... independent set if no two vertices in S are adjacent. ... independent set. The corona G1 ◦ G2 of two graphs G1 and G2 is defined to be the graph. G obtained by taking one copy of G1 and |V(G1)| copies of G2, and then joining the i-th.

  19. Untangling Partnership and Domination Morality

    Directory of Open Access Journals (Sweden)

    David Loye

    2015-06-01

    Full Text Available Riane Eisler’s (1987 cultural transformation theory is an effective framework for understanding many of the constructs that shape society. This article uses Eisler’s theory to explain the formation of morality and the construction of conscience. It contrasts partnership morality and domination morality, and describes the factors that shape our tendency to embrace one or the other. The article helps us understand that we have a choice, and invites us to choose partnership morality.

  20. Investigation of Cyclic Deformation and Fatigue of Polycrystalline Cu under Pure Compression Cyclic Loading Conditions

    Science.gov (United States)

    Hsu, Tzu-Yin Jean

    It is commonly accepted that fatigue crack is initiated under tensile fatigue stresses. However, practical examples demonstrate that cracks may also initiate under pure compressive fluctuating loads such as the failures observed in aircraft landing gear frames. However, the mechanism of such failures is rarely investigated. Furthermore, knowledge on cyclic deformation response under pure compressive fatigue condition is also very limited or non-existent. Our recent work already verified that fatigue cracks may nucleate from stress concentration sites under pure compression fatigue, but whether or not a form of stress concentration is always needed to initiate a crack under pure compression fatigue remains uncertain. In this study, compression fatigue tests under different peak stresses were carried out on smooth bars of fully annealed OFHC Copper. The purpose of these tests is to investigate not only the cyclic deformation response but also the possibility of crack nucleation without the stress concentrator. Results showed that overall the cyclic stress-strain response and microstructural evolution of OFHC Copper under pure compression fatigue exhibits rather dissimilar behaviour compared to those under symmetrical fatigue. The specimens hardened rapidly within 10 cycles under pure compression fatigue unlike the gradual cyclic hardening behaviour in symmetrical fatigue with the same peak stress amplitude. Compressive cyclic creep behaviour was also observed under the same testing conditions. Moreover, unlike conventional tension-compression fatigue, only moderate slip activity was detectable on the surface instead of typical PSB features detected from TEM observations. The surface observations has revealed that surface slip bands did not increase in number nor did they become more pronounced in height with increasing number of cycles. In addition, surface roughening by grain boundary extrusion was detected to become more severe as the cycling progressed. Therefore

  1. A cyclically actuated electrolytic drug delivery device

    KAUST Repository

    Yi, Ying

    2015-01-01

    This work, focusing on an implantable drug delivery system, presents the first prototype electrolytic pump that combines a catalytic reformer and a cyclically actuated mode. These features improve the release performance and extend the lifetime of the device. Using our platinum (Pt)-coated carbon fiber mesh that acts as a catalytic reforming element, the cyclical mode is improved because the faster recombination rate allows for a shorter cycling time for drug delivery. Another feature of our device is that it uses a solid-drug-in-reservoir (SDR) approach, which allows small amounts of a solid drug to be dissolved in human fluid, forming a reproducible drug solution for long-term therapies. We have conducted proof-of-principle drug delivery studies using such an electrolytic pump and solvent blue 38 as the drug substitute. These tests demonstrate power-controlled and pulsatile release profiles of the chemical substance, as well as the feasibility of this device. A drug delivery rate of 11.44 ± 0.56 μg min-1 was achieved by using an input power of 4 mW for multiple pulses, which indicates the stability of our system. © The Royal Society of Chemistry 2015.

  2. Effects of Cyclic Loading on Gravel

    Science.gov (United States)

    Modoni, Giuseppe; Dan, Le Quang; Koseki, Junichi; Maqbool, Sajjad

    The effects of a large number of load repetitions on gravel are discussed based on experimental evidences. To this purpose the results of several triaxial tests carried out on a coarse grained soil, artificially reconstituted at different prescribed levels of density, are reported and compared. The tests reproduce a broad variety of possible field conditions, being performed at different mean effective stresses, by applying sequences of load-unload repetitions, different by number of repetitions and amplitudes of cycles. The analysis of the experimental results has been conducted by focusing the attention on the plastic components of strain, calculated by scaling the non negligible elastic components from the measured ones. A theory for the interpretation of monotonic test results is first briefly presented to form the basis of the analysis of the cyclic test results. This last is referred to the evolution of the stress-strain relationships along with load repetitions, and particularly to the accumulation of distortional and volumetric strains and to the effects of previous cyclic loading on subsequent soil response.

  3. Fault diagnosis of rolling bearing based on cyclic spectrum density

    International Nuclear Information System (INIS)

    Shi Qingfeng; Yan Junming; Zhang Yanhong

    2009-01-01

    The paper considered the vibration signals of rotating equipment as cyclo stationary signals through analyzing the features of this kind of signals. Based on the analytic method of cyclic spectrum density, the paper pointed out that the impact frequency could be extracted effectively with the help of scanning cyclic frequency domain. The validity of the method of cyclic spectrum density is proved by simulating signals and the method is applied to the diagnosis of rolling bearings. (authors)

  4. Synthesis of Cyclic Py-Im Polyamide Libraries

    OpenAIRE

    Li, Benjamin C.; Montgomery, David C.; Puckett, James W.; Dervan, Peter B.

    2013-01-01

    Cyclic Py-Im polyamides containing two GABA turn units exhibit enhanced DNA binding affinity, but extensive studies of their biological properties have been hindered due to synthetic inaccessibility. A facile modular approach toward cyclic polyamides has been developed via microwave-assisted solid-phase synthesis of hairpin amino acid oligomer intermediates followed by macrocyclization. A focused library of cyclic polyamides 1–7 targeted to the androgen response element (ARE) and the estrogen...

  5. Cyclical mastalgia: Prevalence and associated determinants in Hamadan City, Iran

    OpenAIRE

    Shobeiri, Fatemeh; Oshvandi, Khodayar; Nazari, Mansour

    2016-01-01

    Objective: To assess prevalence of cyclical mastalgia and its main determinants in women who attended in health centers of Hamadan City, Iran. Methods: This case–control study was conducted on 400 women (case: cyclical mastalgia, n = 240; control: without cyclical mastalgia, n = 160) who attended family planning clinic for routine follow-up in health centers. The cluster sampling was used. Information was collected by interviewing and using a standardized validated questionnaire. Severity ...

  6. Cyclic Team Teaching in Ninth-Grade Physical Science

    Science.gov (United States)

    Swainson, Ralph; And Others

    1971-01-01

    Presents the instructional procedures used in a team teaching situation. Identifies advantages and problems encountered in cyclic approach to demonstration, laboratory, programed, and large group activities. (DS)

  7. Dominant Maneuver: The Art of the Possible

    National Research Council Canada - National Science Library

    Brozenick, Norman

    1997-01-01

    ...) dominant maneuver, (2) precision engagement, (3) full dimensional protection, and (4) focused logistics. This paper defines dominant maneuver as American maneuver warfare for the early 21st century...

  8. Normal and Leukemic Hematopoiesis

    NARCIS (Netherlands)

    Vercauteren, Suzanne Maria

    2003-01-01

    Acute Myeloid Leukemia (AML) is a clonal myeloproliferative disease characterized by an uncontrolled proliferation and block in differentiation of myeloid committed blood cells in the bone marrow. Despite the lack of mature cells derived from the leukemic clone in the majority of AML patients, AML

  9. Ergodic averages via dominating processes

    DEFF Research Database (Denmark)

    Møller, Jesper; Mengersen, Kerrie

    2006-01-01

    We show how the mean of a monotone function (defined on a state space equipped with a partial ordering) can be estimated, using ergodic averages calculated from upper and lower dominating processes of a stationary irreducible Markov chain. In particular, we do not need to simulate the stationary...... Markov chain and we eliminate the problem of whether an appropriate burn-in is determined or not. Moreover, when a central limit theorem applies, we show how confidence intervals for the mean can be estimated by bounding the asymptotic variance of the ergodic average based on the equilibrium chain....

  10. Single-bundle nanofiber based OFETs fabricated from a cyclic conjugated organogelator with high field-effect mobility and high photoresponsivity.

    Science.gov (United States)

    Guan, Ying-Shi; Qin, Yunke; Sun, Yuanhui; Wang, Chao; Xu, Wei; Zhu, Daoben

    2015-08-07

    Single-bundle nanofiber based OFETs were fabricated from a cyclic conjugated organogelator, using a simple gelation method. The devices exhibited typical p-type semiconductor properties with dominant hole transport both in the dark and upon illumination under ambient conditions.

  11. Isothermal and cyclic oxidation resistance of pack siliconized Mo–Si–B alloy

    Energy Technology Data Exchange (ETDEWEB)

    Majumdar, Sanjib, E-mail: sanjib@barc.gov.in

    2017-08-31

    Highlights: • Pack-siliconizing of Mo–Si–B alloy improves its oxidation resistance at 750, 900 and 1400 °C. • A marginal weight change of the coated alloy is detected in isothermal and cyclic oxidation tests. • Kinetics of growth of protective SiO{sub 2} scale is much faster at 1400 °C. • Self-healing SiO{sub 2} is developed at the cracks formed in MoSi{sub 2} layer during cyclic oxidation tests. - Abstract: Oxidation behaviour of MoSi{sub 2} coated Mo–9Si–8B–0.75Y (at.%) alloy has been investigated at three critical temperatures including 750, 900 and 1400 °C in static air. Thermogravimetric analysis (TGA) data indicates a remarkable improvement in the oxidation resistance of the silicide coated alloy in both isothermal and cyclic oxidation tests. The cross-sectional scanning electron microscopy and energy dispersive spectroscopic analysis reveal the occurrence of internal oxidation particularly at the crack fronts formed in the outer MoSi{sub 2} layer during thermal cycling. The dominant oxidation mechanisms at 750–900 °C and 1400 °C are identified. Development of MoB inner layer further improves the oxidation resistance of the silicide coated alloy.

  12. Effects of X-rays and γ-rays on reconstitution of hematopoiesis and immunity after allogeneic bone marrow transplantation

    International Nuclear Information System (INIS)

    Pan Bin; Zeng Lingyu; Cheng Hai; Song Guoliang; Jia Lu; Yan Zhiling; Chen Chong; Xu Kailin

    2011-01-01

    those of the X-ray + transplantation group (t=3.624, 6.695, P<0.05). The chimeric rats of the peripheral lymphocytes 10 and 20 days after transplantation of the γ-ray + transplantation group were both significantly higher than those of the X-ray + transplantation group (t=12.317, 8.295, P<0.05). The homogeneity rate of transplantation of the γ-ray + transplantation group was better than that of the X-ray + transplantation group. Conclusions: As a conditioning regimen in allogeneic hematopoietic stem cell transplantation γ-ray irradiation causes milder injury and accelerated reconstitution of hematopoiesis and immunity, in comparison with X-ray irradiation. (authors)

  13. Estrous Cyclicity in Mice During Simulated Weightlessness

    Science.gov (United States)

    Moyer, E. L.; Talyansky, Y.; Scott, R. T.; Tash, J. S.; Christenson, L. K.; Alwood, J. S.; Ronca, A. E.

    2017-01-01

    Hindlimb unloading (HU) is a rodent model system used to simulate weightlessness experienced in space. However, some effects of this approach on rodent physiology are under-studied, specifically the effects on ovarian estrogen production which drives the estrous cycle. To resolve this deficiency, we conducted a ground-based validation study using the HU model, while monitoring estrous cycles in 16-weeks-old female C57BL6 mice. Animals were exposed to HU for 12 days following a 3 day HU cage acclimation period, and estrous cycling was analyzed in HU animals (n=22), normally loaded HU Cage Pair-Fed controls (CPF; n=22), and Vivarium controls fed ad libitum (VIV; n=10). Pair feeding was used to control for potential nutritional deficits on ovarian function. Vaginal cells were sampled daily in all mice via saline lavage. Cells were dried and stained with crystal violet, and the smears evaluated using established vaginal cytology techniques by two individuals blinded to the animal treatment group. Estrous cyclicity was disrupted in nearly all HU and CPF mice, while those maintained in VIV had an average normal cycle length of 4.8+/- 0.5 days, with all stages in the cycle visibly observed. CPF and HU animals arrested in the diestrous phase, which precedes the pre-ovulatory estrogen surge. Additionally, infection-like symptoms characterized by vaginal discharge and swelling arose in several HU animals, which we suspect was due to an inability of these mice to properly groom themselves, and/or due to the change in the gravity vector relative to the vaginal opening, which prevented drainage of the lavage solution. Pair-feeding resulted in similar weight gains of HU and CPF (1.5% vs 3.0%, respectively). The current results indicate that pair-feeding controlled weight gain and that the HU cage alone influenced estrous cyclicity. Thus, longer acclimation needs to be tested to determine if and when normal estrous cycling resumes in non-loaded mice in HU cages prior to HU

  14. Estrous Cyclicity of Mice During Simulated Weightlessness

    Science.gov (United States)

    Moyer, Eric; Talyansky, Yuli; Scott, Ryan; Tash, Joseph; Christenson, Lane; Alwood, Joshua; Ronca, April

    2017-01-01

    Hindlimb unloading (HU) is a rodent model system used to simulate weightlessness experienced in space. However, some effects of this approach on rodent physiology are under-studied, specifically the effects on ovarian estrogen production which drives the estrous cycle. To resolve this deficiency, we conducted a ground-based validation study using the HU model, while monitoring estrous cycles in 16-weeks-old female C57BL6 mice. Animals were exposed to HU for 12 days following a 3 day HU cage acclimation period, and estrous cycling was analyzed in HU animals (n22), normally loaded HU Cage Pair-Fed controls (CPF; n22), and Vivarium controls fed ad libitum (VIV; n10). Pair feeding was used to control for potential nutritional deficits on ovarian function. Vaginal cells were sampled daily in all mice via saline lavage. Cells were dried and stained with crystal violet, and the smears evaluated using established vaginal cytology techniques by two individuals blinded to the animal treatment group. Estrous cyclicity was disrupted in nearly all HU and CPF mice, while those maintained in VIV had an average normal cycle length of 4.8 0.5 days, with all stages in the cycle visibly observed. CPF and HU animals arrested in the diestrous phase, which precedes the pre-ovulatory estrogen surge. Additionally, infection-like symptoms characterized by vaginal discharge and swelling arose in several HU animals, which we suspect was due to an inability of these mice to properly groom themselves, andor due to the change in the gravity vector relative to the vaginal opening, which prevented drainage of the lavage solution. Pair-feeding resulted in similar weight gains of HU and CPF (1.5 vs 3.0, respectively). The current results indicate that pair-feeding controlled weight gain and that the HU cage alone influenced estrous cyclicity. Thus, longer acclimation needs to be tested to determine if and when normal estrous cycling resumes in non-loaded mice in HU cages prior to HU testing. Future

  15. Biologic activity of cyclic and caged phosphates: a review.

    Science.gov (United States)

    Lorke, Dietrich E; Stegmeier-Petroianu, Anka; Petroianu, Georg A

    2017-01-01

    The recognition in the early 1960s by Morifusa Eto that tri-o-cresyl phosphate (TOCP) is hydroxylated by the cytochrome P450 system to an intermediate that spontaneously cyclizes to a neurotoxic phosphate (saligenin phosphate ester) ignited the interest in this group of compounds. Only the ortho isomer can cyclize and clinically cause Organo Phosphate Induced Delayed Neurotoxicity (OPIDN); the meta and para isomers of tri-cresyl phosphate are not neuropathic because they are unable to form stable cyclic saligenin phosphate esters. This review identifies the diverse biological effects associated with various cyclic and caged phosphates and phosphonates and their possible use. Cyclic compounds that inhibit acetylcholine esterase (AChE), such as salithion, can be employed as pesticides. Others are neurotoxic, most probably because of inhibition of neuropathy target esterase (NTE). Cyclic phosphates that inhibit lipases, the cyclipostins, possibly represent promising therapeutic avenues for the treatment of type 2 diabetes mellitus and/or microbial infections; those compounds inhibiting β-lactamase may prevent bacterial resistance against β-lactam antibiotics. Naturally occurring cyclic phosphates, such as cyclic AMP, cyclic phosphatidic acid and the ryanodine receptor modulator cyclic adenosine diphosphate ribose, play an important physiological role in signal transduction. Moreover, some cyclic phosphates are GABA-antagonists, while others are an essential component of Molybdenum-containing enzymes. Some cyclic phosphates (cyclophosphamide, ifosfamide) are clinically used in tumor therapy, while the coupling of therapeutic agents with other cyclic phosphates (HepDirect® Technology) allows drugs to be targeted to specific organs. Possible clinical applications of these compounds are considered. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  16. Magnetoelastic Demagnetization of Steel under Cyclic Loading

    Science.gov (United States)

    Muratov, K. R.; Novikov, V. F.; Neradovskii, D. F.; Kazakov, R. Kh.

    2018-01-01

    Magnetoelastic demagnetization of steel samples under cyclic tensile loads has been analyzed. It has been established that values of residual magnetization that correspond to peak loads are characterized by the power-law dependence on the number of loading cycles. In some cases, in the region of high loads, the qualitative transition to exponential dependence has been observed. Coefficients of the power-law approximation of peak magnetization depend on the value of amplitude load and have specific characteristics in the vicinity of characteristic loads. The ratios of approximated slide load coefficients depending on the load are common for the three considered samples, and there is an outburst in the vicinity of the fatigue limit, which can be used as the basis for developing the rapid nondestructive method for determination of this limit.

  17. The cyclic universe: An informal introduction

    International Nuclear Information System (INIS)

    Steinhaxdt, Paul J.; Turok, Neil

    2003-01-01

    The Cyclic Model is a radical, new cosmological scenario which proposes that the Universe undergoes an endless sequence of epochs which begin with a 'big bang' and end in a 'big crunch.' When the Universes bounces from contraction to re-expansion, the temperature and density remain finite. The model does not include a period of rapid inflation, yet it reproduces all of the successful predictions of standard big bang and inflationary cosmology. We point out numerous novel elements that have not been used previously which may open the door to further alternative cosmologies. Although the model is motivated by M-theory, branes and extra dimensions, here we show that the scenario can be described almost entirely in terms of conventional 4d field theory and 4d cosmology

  18. Janus cyclic peptide-polymer nanotubes

    Science.gov (United States)

    Danial, Maarten; My-Nhi Tran, Carmen; Young, Philip G.; Perrier, Sébastien; Jolliffe, Katrina A.

    2013-11-01

    Self-assembled nanotubular structures have numerous potential applications but these are limited by a lack of control over size and functionality. Controlling these features at the molecular level may allow realization of the potential of such structures. Here we report a new generation of self-assembled cyclic peptide-polymer nanotubes with dual functionality in the form of either a Janus or mixed polymeric corona. A ‘relay’ synthetic strategy is used to prepare nanotubes with a demixing or mixing polymeric corona. Nanotube structure is assessed in solution using 1H-1H nuclear Overhauser effect spectroscopy NMR, and in bulk using differential scanning calorimetry. The Janus nanotubes form artificial pores in model phospholipid bilayers. These molecules provide a viable pathway for the development of intriguing nanotubular structures with dual functionality via a demixing or a mixing polymeric corona and may provide new avenues for the creation of synthetic transmembrane protein channel mimics.

  19. Cyclic steps incised on experimental bedrock

    Science.gov (United States)

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

    2013-12-01

    In rivers flowing in mountain areas, a series of steps are often observed on bedrock. They are thought to be cyclic steps formed due to erosion of bedrock, which should be driven by abrasion due to bedload sediment transport. We demonstrated a series of flume experiments of the formation of cyclic steps on bedrock by abrasion due to bedload transportation using weak mortar as the model bedrock. We also compared the shapes of the steps reproduced in the experiments with those obtained in the analysis. The experiments were conducted using a 1.5 m long, 2 cm wide, and 20 cm deep flume made of glass in Osaka Institute of Technology. The flume has 10-cm-high weirs at both ends, so that there is a 10-cm-deep reservoir. We put mortar into the reservoir and hardened it. In order to make a highly erodible mortar, we casted the mortar with extremely low amount of cement. The ratio of cement, sand (0.2 mm in diameter), and water is x:150:50 (x ranges 1-3). The flume is tilted by 10 degrees. The water and colored sand is supplied from a head tank to the upstream end of the flume, flows on 'model bedrock' in the flume, and was dropped from the downstream end. We observed morphological changes of the surface of the bedrock by photos. We also used a laser displacement sensor to measure the surface topography of the 'model bedrock' before and after each run. The configuration of steps largely depends on the hardness of model bedrocks. In the case of the softest model bedrock (cement-sand-water ratio is 1:150:50) with small amount of sand, long-drawn potholes tend to be formed. Clear cyclic steps are formed on harder model bedrocks with large cement-sand-water ratios such as 2:150:50 and 3:150:50. When a series of steps are formed on the bed, typical wavelength and wave height are approximately 20 cm, and 2 - 3 cm, respectively. The general shape of a step is characterized by a relatively long downward-inclined slope just upstream of a short upward-inclined slope. The feature of

  20. Protein Misfolding Cyclic Amplification of Infectious Prions.

    Science.gov (United States)

    Moda, Fabio

    2017-01-01

    Transmissible spongiform encephalopathies, or prion diseases, are a group of incurable disorders caused by the accumulation of an abnormally folded prion protein (PrP Sc ) in the brain. According to the "protein-only" hypothesis, PrP Sc is the infectious agent able to propagate the disease by acting as a template for the conversion of the correctly folded prion protein (PrP C ) into the pathological isoform. Recently, the mechanism of PrP C conversion has been mimicked in vitro using an innovative technique named protein misfolding cyclic amplification (PMCA). This technology represents a great tool for studying diverse aspects of prion biology in the field of basic research and diagnosis. Moreover, PMCA can be expanded for the study of the misfolding process associated to other neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and frontotemporal lobar degeneration. © 2017 Elsevier Inc. All rights reserved.

  1. Extramedullary hematopoiesis on 18F-FDG PET/CT in a patient with thalassemia and nasopharyngeal carcinoma: A case report and literature review.

    Science.gov (United States)

    Qiu, Dasheng; Hu, Xiaoyan; Xu, Liying; Guo, Xiaofang

    2015-01-01

    Extramedullary hematopoiesis (EMH) occurs in various bone marrow disorders and is most commonly seen in thalassemia and myelofibrosis. Here, we report a patient with beta-thalassemia and nasopharyngeal carcinoma having intrathoracic EMH. Our patient is a 42-year-old man who complained of chest discomfort for a month. He was confirmed nasopharyngeal carcinoma (T3N2M0) by histopathology and received chemoradiotherapy 4 months ago. The patient had a long history of beta-thalassemia and a splenectomy due to splenomegaly at 12 years of age. Computed tomography (CT) scan of the chest showed multiple soft tissue masses in bilateral thoracic cavities. 18F-FDG-PET showed no obvious increase of fluorodeoxyglucose (18F-FDG) uptake by the lesions, with an SUVmax value of approximately 2.19. These lesions were considered EMH. The patient had been followed up for more than 1 year, and there were no changes of the lesions in the thoracic cavities.

  2. Co-Roman domination in graphs

    Indian Academy of Sciences (India)

    2Department of Computer Science, Liverpool Hope University, Liverpool, UK. 3Department of Computer .... such as Roman domination, weak Roman domination and secure domination, which have been investigated by ... A foolproof secure dominating function (FSDF) is a safe function f = (V0,V1) such that for each u ∈ V0 ...

  3. Multicomponent Synthesis of Cyclic Depsipeptide Mimics by Ugi Reaction Including Cyclic Hemiacetals Derived from Asymmetric Organocatalysis.

    Science.gov (United States)

    de la Torre, Alexander F; Rivera, Daniel G; Concepción, Odette; Echemendia, Radell; Correa, Arlene G; Paixão, Márcio W

    2016-02-05

    The synthesis of novel cyclic depsipeptide mimics by means of an organocatalytic conjugate addition, leading to chiral cyclic hemiacetals, followed by a multicomponent reaction with α-amino acids and isocyanides, is described. The initial organocatalytic step is employed for the asymmetric derivatization of α,β-unsaturated aldehydes to 4,5-disubstituted 2-hydroxytetrahydropyrans, which are next used as chiral bifunctional substrates on the Ugi five-center three-component reaction, giving rise to nine-membered-ring lactones. This sequential approach proved to be suitable for the rapid generation of molecular complexity through the combination of aliphatic, dipeptidic, glucosidic, and lipidic isocyanides with several amino acids, thus giving access to amido-, glyco-, and lipo-depsipeptide scaffolds featuring natural product-like structures.

  4. Cyclic Oxidation Behaviour of Domestic Superalloys at Elevated Temperature

    International Nuclear Information System (INIS)

    Kang, S. C.; Kim, G. M.; Chon, Y. G.

    1991-01-01

    The cyclic oxidation behaviour of commercial superalloys produced in Korea was investigated in air at 1000 .deg. C and 1100 .deg. C. Cyclic oxidation test was carried out by cyclically oxidizing the specimens in an apparatus which periodically removed the specimens from the furnace and reinserted them. The influence of growth stress and thermal stress on the cyclic oxidation was studied by examination of the oxide structures, their morphologies, and EDS line scanning of cross-section of cyclically oxidized specimens. The results showed that Inconel 601 was the best in the cyclic oxidation resistance among the tested alloys, followed by Nimonic 80A, Incoloy 825 and Inconel 718 at 1100 .deg. C. As in the case of the isothermal oxidation, relatively pure Cr 2 O 3 was effective in the beginning of cyclic oxidation experiment. But, later on, other oxidation products as well as Cr 2 O 3 were formed, resulting in the spallation of oxide scales. Especially, Nb and Mo in the alloys were determental to the cyclic oxidation behavior

  5. Classifying spaces with virtually cyclic stabilizers for linear groups

    DEFF Research Database (Denmark)

    Degrijse, Dieter Dries; Köhl, Ralf; Petrosyan, Nansen

    2015-01-01

    We show that every discrete subgroup of GL(n, ℝ) admits a finite-dimensional classifying space with virtually cyclic stabilizers. Applying our methods to SL(3, ℤ), we obtain a four-dimensional classifying space with virtually cyclic stabilizers and a decomposition of the algebraic K-theory of its...

  6. Evaluating cyclic fatigue of sealants during outdoor testing

    Science.gov (United States)

    R. Sam Williams; Steven Lacher; Corey Halpin; Christopher White

    2009-01-01

    A computer-controlled test apparatus (CCTA) and other instrumentation for subjecting sealant specimens to cyclic fatigue during outdoor exposure was developed. The CCTA enables us to use weather-induced conditions to cyclic fatigue specimens and to conduct controlled tests in-situ during the outdoor exposure. Thermally induced dimensional changes of an aluminum bar...

  7. Improvements of cyclic somatic embryogenesis of cassava (Manihot esculenta Crantz).

    NARCIS (Netherlands)

    Raemakers, C.J.J.M.; Schavemaker, C.M.; Jacobsen, E.; Visser, R.G.F.

    1993-01-01

    In cassava a cyclic system of somatic embryogenesis was developed. Primary (torpedo shaped or germinated) embryos, originating from leaf lobes, could only be obtained after culture on solid medium. Cyclic embryos, originating from embryos, could be obtained in both liquid and on solid medium. The

  8. Supplementary Material for: The arabidopsis cyclic nucleotide interactome

    KAUST Repository

    Donaldson, Lara

    2016-01-01

    Abstract Background Cyclic nucleotides have been shown to play important signaling roles in many physiological processes in plants including photosynthesis and defence. Despite this, little is known about cyclic nucleotide-dependent signaling mechanisms in plants since the downstream target proteins remain unknown. This is largely due to the fact that bioinformatics searches fail to identify plant homologs of protein kinases and phosphodiesterases that are the main targets of cyclic nucleotides in animals. Methods An affinity purification technique was used to identify cyclic nucleotide binding proteins in Arabidopsis thaliana. The identified proteins were subjected to a computational analysis that included a sequence, transcriptional co-expression and functional annotation analysis in order to assess their potential role in plant cyclic nucleotide signaling. Results A total of twelve cyclic nucleotide binding proteins were identified experimentally including key enzymes in the Calvin cycle and photorespiration pathway. Importantly, eight of the twelve proteins were shown to contain putative cyclic nucleotide binding domains. Moreover, the identified proteins are post-translationally modified by nitric oxide, transcriptionally co-expressed and annotated to function in hydrogen peroxide signaling and the defence response. The activity of one of these proteins, GLYGOLATE OXIDASE 1, a photorespiratory enzyme that produces hydrogen peroxide in response to Pseudomonas, was shown to be repressed by a combination of cGMP and nitric oxide treatment. Conclusions We propose that the identified proteins function together as points of cross-talk between cyclic nucleotide, nitric oxide and reactive oxygen species signaling during the defence response.

  9. Rank equivalent and rank degenerate skew cyclic codes

    DEFF Research Database (Denmark)

    Martinez Peñas, Umberto

    2017-01-01

    Two skew cyclic codes can be equivalent for the Hamming metric only if they have the same length, and only the zero code is degenerate. The situation is completely different for the rank metric. We study rank equivalences between skew cyclic codes of different lengths and, with the aim of finding...

  10. Structure and stability of spiro-cyclic water clusters

    Indian Academy of Sciences (India)

    Administrator

    donates two protons, resulting in an overall stabili- zation of the spiro-cyclic structure. A close scrutiny. Figure 1. Optimized geometries of different spiro- cyclic water clusters obtained using HF/6-311++G** cal- culation. These clusters are found to be stable without any reorganization during energy minimization at DFT.

  11. Development of Pore Pressure and Material Damping during Cyclic Loading

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    1994-01-01

    The behaviour of sand during cyclic loading can be characterized as "stabilization", "instant stabilization". "pore pressure buildup" and "liquefaction". The terminologies can be defined exactly by a simple mathematical formulation based on the existence of a cyclic stable state. By introducing...

  12. Behaviour of Dense Frederikshavn Sand During Cyclic Loading

    DEFF Research Database (Denmark)

    Nielsen, Søren Kjær; Shajarati, Amir; Sørensen, Kris Wessel

    of Frederikshavn Sand for an arbitrary stress level and cyclic loading condition. It is discovered that the governing parameters regarding the response is dependent on the stress path and insitu conditions; initial pore pressure, stress state and the combination of average and cyclic shear stresses....

  13. Structure and stability of spiro-cyclic water clusters

    Indian Academy of Sciences (India)

    Administrator

    Abstract. The structure and stability of spiro-cyclic water clusters containing up to 32 water molecules have been investigated at different levels of theory. Although there exist minima lower in energy than these spiro-cyclic clusters, calculations at the Hartree–Fock level, density functional theory using B3LYP parametrization ...

  14. On domination multisubdivision number of unicyclic graphs

    Directory of Open Access Journals (Sweden)

    Joanna Raczek

    2018-01-01

    Full Text Available The paper continues the interesting study of the domination subdivision number and the domination multisubdivision number. On the basis of the constructive characterization of the trees with the domination subdivision number equal to 3 given in [H. Aram, S.M. Sheikholeslami, O. Favaron, Domination subdivision number of trees, Discrete Math. 309 (2009, 622-628], we constructively characterize all connected unicyclic graphs with the domination multisubdivision number equal to 3. We end with further questions and open problems.

  15. Design of mild steel structures under unequal cyclic loads

    International Nuclear Information System (INIS)

    In this paper a method is proposed to investigate the behavior and life of structural components under unequal cyclic loading conditions. Appropriate cyclic moment-curvature relations and life information, in the form of life versus extreme fiber strain, are developed from tests on beams under pure bending conditions. Theoretical predictions of behavior are based on structural geometry and the cyclic moment-curvature relations used in association with the simple curvature-area method. Structural life is also predicted using the life information developed and the theoretical strain history at the critical section in conjunction with a linear damage summation criterion. Theoretical predictions of behavior and life compare reasonably well with the experiments. Based on this study, a design procedure is proposed for mild steel components subjected to unequal cyclic loading conditions. The loads on the tested components were such that they failed due to low cyclic fatigue (i.e., at less than 10 5 cycles)

  16. History-independent cyclic response of nanotwinned metals

    Science.gov (United States)

    Pan, Qingsong; Zhou, Haofei; Lu, Qiuhong; Gao, Huajian; Lu, Lei

    2017-11-01

    Nearly 90 per cent of service failures of metallic components and structures are caused by fatigue at cyclic stress amplitudes much lower than the tensile strength of the materials involved. Metals typically suffer from large amounts of cumulative, irreversible damage to microstructure during cyclic deformation, leading to cyclic responses that are unstable (hardening or softening) and history-dependent. Existing rules for fatigue life prediction, such as the linear cumulative damage rule, cannot account for the effect of loading history, and engineering components are often loaded by complex cyclic stresses with variable amplitudes, mean values and frequencies, such as aircraft wings in turbulent air. It is therefore usually extremely challenging to predict cyclic behaviour and fatigue life under a realistic load spectrum. Here, through both atomistic simulations and variable-strain-amplitude cyclic loading experiments at stress amplitudes lower than the tensile strength of the metal, we report a history-independent and stable cyclic response in bulk copper samples that contain highly oriented nanoscale twins. We demonstrate that this unusual cyclic behaviour is governed by a type of correlated ‘necklace’ dislocation consisting of multiple short component dislocations in adjacent twins, connected like the links of a necklace. Such dislocations are formed in the highly oriented nanotwinned structure under cyclic loading and help to maintain the stability of twin boundaries and the reversible damage, provided that the nanotwins are tilted within about 15 degrees of the loading axis. This cyclic deformation mechanism is distinct from the conventional strain localizing mechanisms associated with irreversible microstructural damage in single-crystal, coarse-grained, ultrafine-grained and nanograined metals.

  17. Cyclic nucleotide specific phosphodiesterases of Leishmania major

    Directory of Open Access Journals (Sweden)

    Linder Markus

    2006-03-01

    Full Text Available Abstract Background Leishmania represent a complex of important human pathogens that belong to the systematic order of the kinetoplastida. They are transmitted between their human and mammalian hosts by different bloodsucking sandfly vectors. In their hosts, the Leishmania undergo several differentiation steps, and their coordination and optimization crucially depend on numerous interactions between the parasites and the physiological environment presented by the fly and human hosts. Little is still known about the signalling networks involved in these functions. In an attempt to better understand the role of cyclic nucleotide signalling in Leishmania differentiation and host-parasite interaction, we here present an initial study on the cyclic nucleotide-specific phosphodiesterases of Leishmania major. Results This paper presents the identification of three class I cyclic-nucleotide-specific phosphodiesterases (PDEs from L. major, PDEs whose catalytic domains exhibit considerable sequence conservation with, among other, all eleven human PDE families. In contrast to other protozoa such as Dictyostelium, or fungi such as Saccharomyces cerevisiae, Candida ssp or Neurospora, no genes for class II PDEs were found in the Leishmania genomes. LmjPDEA contains a class I catalytic domain at the C-terminus of the polypeptide, with no other discernible functional domains elsewhere. LmjPDEB1 and LmjPDEB2 are coded for by closely related, tandemly linked genes on chromosome 15. Both PDEs contain two GAF domains in their N-terminal region, and their almost identical catalytic domains are located at the C-terminus of the polypeptide. LmjPDEA, LmjPDEB1 and LmjPDEB2 were further characterized by functional complementation in a PDE-deficient S. cerevisiae strain. All three enzymes conferred complementation, demonstrating that all three can hydrolyze cAMP. Recombinant LmjPDEB1 and LmjPDEB2 were shown to be cAMP-specific, with Km values in the low micromolar range

  18. Progress on Autosomal Dominant Polycystic Kidney Disease

    African Journals Online (AJOL)

    Cysts of the seminal vesicles, pancreas, and arachnoid ..... AVP = arginine vasopressin; BUN = blood urea nitrogen; cAMP = cyclic adenosine monophosphate; ERK = extracellular signal- regulated ... MAP = mean arterial pressure; MEK = mitogen extracellular kinase; mTOR = mammalian target of rapamycin; NA = data not.

  19. Cyclic and circadian variations in cardiovascular events.

    Science.gov (United States)

    Elliot, W J

    2001-09-01

    The incidence of many biologic phenomena displays a reproducible and cyclic variation. Cardiovascular disease, the most common cause of death in the United States and other developed countries, also has an intrinsic variation in events. These events are more common in winter, at the beginning of each month, on Mondays (in working people), and during the early morning hours of each day. Recent meta-analyses have quantitated the excess risk of cardiovascular events in the hours around and just after awakening. Between 6 AM and noon, there is a 40% higher risk of heart attack, a 29% increased risk of cardiac death, and a 49% increased risk of stroke (compared with what would be expected if these events happened at random and were evenly distributed throughout the day). These observations have major consequences for emergency medical personnel and medical transport systems. The reasons for these observations are less clear. The circadian pattern of blood pressure (BP) and heart rate may be a major contributor, and long-term "hard end-point" studies designed to test specific pharmacologic interventions targeting the early morning rise in BP and heart rate are underway. Individuals who work night shifts and those whose BP has a different circadian pattern have a higher risk of cardiovascular events, but may be less likely to have an increased risk of cardiovascular events in the morning.

  20. A low-power arcjet cyclic lifetest

    Science.gov (United States)

    Curran, Francis M.; Hardy, Terry L.; Haag, Thomas W.

    1987-01-01

    A cyclic lifetest of a low power dc arcjet thruster using a hydrogen/nitrogen propellant mixture simulating hydrazine is currently in progress. Over 300 hr of operation have been accumulated to date in 2 hr duty cycles at a power level of about 1.15 kW, approximating that available on commercial communications satellites. A burn-in period was carried out before consistent operation was attained. After this period, the arcjet operated in a very stable fashion from cycle to cycle. At the beginning of each cycle, there was a brief starting transient followed by a rapid rise to a steady-state voltage. The steady-state voltage increased by about 5 V over the first 95 cycles. After this, it increased by only 1 V through the remainder of the test. Thrust measurements taken before the life test and again after the completion of the 144th cycle showed that both thrust, specific impulse, and arc voltage had increased over this period of operation. No life limiting mechanisms were observed during the course of the testing.

  1. Bucket foundations under lateral cyclic loading

    DEFF Research Database (Denmark)

    Foglia, Aligi

    To enable a prosperous development of offshore wind energy, economically feasible technologies must be developed. The monopod bucket foundation is likely to become a cost-effective sub-structure for offshore wind turbines and has the potential to make offshore wind more cost-competitive in the en......To enable a prosperous development of offshore wind energy, economically feasible technologies must be developed. The monopod bucket foundation is likely to become a cost-effective sub-structure for offshore wind turbines and has the potential to make offshore wind more cost......-competitive in the energy market. This thesis addresses issues concerning monopod bucket foundations in the hope of providing tools and ideas that could be used to optimize the design of this sub-structure. The work is focussed on the behaviour of bucket foundations under lateral cyclic loading. Other related...... and propaedeutic topics, such as bucket foundations under transient lateral loading and under monotonic lateral loading, are also investigated. All the scientific work is fundamentally based on small-scale experimental tests of bucket foundations in dense water-saturated sand. The most important scientific...

  2. Interuniversal entanglement in a cyclic multiverse

    Science.gov (United States)

    Robles-Pérez, Salvador; Balcerzak, Adam; Dąbrowski, Mariusz P.; Krämer, Manuel

    2017-04-01

    We study scenarios of parallel cyclic multiverses which allow for a different evolution of the physical constants, while having the same geometry. These universes are classically disconnected, but quantum-mechanically entangled. Applying the thermodynamics of entanglement, we calculate the temperature and the entropy of entanglement. It emerges that the entropy of entanglement is large at big bang and big crunch singularities of the parallel universes as well as at the maxima of the expansion of these universes. The latter seems to confirm earlier studies that quantum effects are strong at turning points of the evolution of the universe performed in the context of the timeless nature of the Wheeler-DeWitt equation and decoherence. On the other hand, the entropy of entanglement at big rip singularities is going to zero despite its presumably quantum nature. This may be an effect of total dissociation of the universe structures into infinitely separated patches violating the null energy condition. However, the temperature of entanglement is large/infinite at every classically singular point and at maximum expansion and seems to be a better measure of quantumness.

  3. Simulations of Granular Particles Under Cyclic Shear

    Science.gov (United States)

    Royer, John; Chaikin, Paul

    2012-02-01

    We perform molecular dynamics (MD) simulations of spherical grains subjected to cyclic, quasi-static shear in a 3D parallelepiped shear cell. This virtual shear cell is constructed out of rough, bumpy walls in order to minimize wall-induced ordering and has an open top surface to allow the packing to readily dilate or compact. Using a standard routine for MD simulations of frictional grains, we simulate over 1000 shear cycles, measuring grain displacements, the local packing density and changes in the contact network. Varying the shear amplitude and the friction coefficient between grains, we map out a phase diagram for the different types of behavior exhibited by these sheared grains. With low friction and high enough shear, the grains can spontaneously order into densely packed crystals. With low shear and increasing friction the packing remains disordered, yet the grains arrange themselves into configurations which exhibit limit cycles where all grains return to the same position after each full shear cycle. At higher shear and friction there is a transition to a diffusive state, where grains continue rearrange and move throughout the shear cell.

  4. Copper Regulates Cyclic AMP-Dependent Lipolysis

    Science.gov (United States)

    Krishnamoorthy, Lakshmi; Cotruvo, Joseph A.; Chan, Jefferson; Kaluarachchi, Harini; Muchenditsi, Abigael; Pendyala, Venkata S.; Jia, Shang; Aron, Allegra T.; Ackerman, Cheri M.; Vander Wal, Mark N.; Guan, Timothy; Smaga, Lukas P.; Farhi, Samouil L.; New, Elizabeth J.; Lutsenko, Svetlana; Chang, Christopher J.

    2016-01-01

    Cell signaling relies extensively on dynamic pools of redox-inactive metal ions such as sodium, potassium, calcium, and zinc, but their redox-active transition metal counterparts such as copper and iron have been studied primarily as static enzyme cofactors. Here we report that copper is an endogenous regulator of lipolysis, the breakdown of fat, which is an essential process in maintaining the body's weight and energy stores. Utilizing a murine model of genetic copper misregulation, in combination with pharmacological alterations in copper status and imaging studies in a 3T3-L1 white adipocyte model, we demonstrate that copper regulates lipolysis at the level of the second messenger, cyclic AMP (cAMP), by altering the activity of the cAMP-degrading phosphodiesterase PDE3B. Biochemical studies of the copper-PDE3B interaction establish copper-dependent inhibition of enzyme activity and identify a key conserved cysteine residue within a PDE3-specific loop that is essential for the observed copper-dependent lipolytic phenotype. PMID:27272565

  5. Noise-guided evolution within cyclical interactions

    International Nuclear Information System (INIS)

    Perc, Matjaz; Szolnoki, Attila

    2007-01-01

    We study a stochastic predator-prey model on a square lattice, where each of the six species has two superior and two inferior partners. The invasion probabilities between species depend on the predator-prey pair and are supplemented by Gaussian noise. Conditions are identified that warrant the largest impact of noise on the evolutionary process, and the results of Monte Carlo simulations are qualitatively reproduced by a four-point cluster dynamical mean-field approximation. The observed noise-guided evolution is deeply routed in short-range spatial correlations, which is supported by simulations on other host lattice topologies. Our findings are conceptually related to the coherence resonance phenomenon in dynamical systems via the mechanism of threshold duality. We also show that the introduced concept of noise-guided evolution via the exploitation of threshold duality is not limited to predator-prey cyclical interactions, but may apply to models of evolutionary game theory as well, thus indicating its applicability in several different fields of research

  6. Dominant drivers of business students

    Directory of Open Access Journals (Sweden)

    Radu Cătălina

    2017-07-01

    Full Text Available Taibi Kahler wrote in 1974 a theory about five main drivers that could explain people’s motivation and a series of positive and negative behavior patterns: Be Strong, Be Perfect, Hurry Up, Try Hard and Please People. Of course, we consider there is no absolute positive or negative behavior, since (1 everything needs to be analyzed by taking into account the context and (2 any behavior pattern can mean a series of advantages as long as people understand their own values, beliefs, attitudes and behaviors. It would be interesting to link Kahler’s drivers to the educational process, in order to be able to adapt our courses and our teaching styles to students’ requirements and also to the requirements in the labor market. Our paper is built on literature review and a questionnaire applied to a sample of 607 students in Bucharest University of Economic Studies, Romania. Information was processed with Microsoft Excel 2013, in order to look at the main working styles our students have, at the main explanations for the differences between them and in order to test a series of hypotheses. We were interested to look at the main traits of the current generation of students in our university: dominant drivers, roles of managers and specialists, the attractiveness of the entrepreneurial career path, etc. and at a series of patterns (i.e. gender-related differences. We consider results of this study are useful both for teaching and research purposes. In terms of teaching, we plan to adapt our educational methods in order to improve the educational process.

  7. On The Roman Domination Stable Graphs

    Directory of Open Access Journals (Sweden)

    Hajian Majid

    2017-11-01

    Full Text Available A Roman dominating function (or just RDF on a graph G = (V,E is a function f : V → {0, 1, 2} satisfying the condition that every vertex u for which f(u = 0 is adjacent to at least one vertex v for which f(v = 2. The weight of an RDF f is the value f(V (G = Pu2V (G f(u. The Roman domination number of a graph G, denoted by R(G, is the minimum weight of a Roman dominating function on G. A graph G is Roman domination stable if the Roman domination number of G remains unchanged under removal of any vertex. In this paper we present upper bounds for the Roman domination number in the class of Roman domination stable graphs, improving bounds posed in [V. Samodivkin, Roman domination in graphs: the class RUV R, Discrete Math. Algorithms Appl. 8 (2016 1650049].

  8. Centrifuge modelling of a laterally cyclic loaded pile

    DEFF Research Database (Denmark)

    Klinkvort, Rasmus Tofte; Leth, Caspar Thrane; Hededal, Ole

    2010-01-01

    A total number of 9 static and 6 cyclic centrifuge tests on laterally loaded piles in very dense, dry sand was erformed. The prototype dimensions of the piles were 1 meter in diameter and penetration depths varying from 6 to 10 meters. The static tests were used to investigate the initial subgrade...... reaction modulus and as a reference for cyclic tests. For the cyclic tests the accumulation of deflections and the change in secant stiffness of the soil from repetitive loading were investigated. From all the tests carried out accumulations of deflections were seen. rom the centrifuge tests it was seen...

  9. Laterally cyclic loading of monopile in dense sand

    DEFF Research Database (Denmark)

    Klinkvort, Rasmus Tofte; Hededal, Ole; Svensson, M.

    2011-01-01

    In order to investigate the response from laterally cyclic loading of monopiles a large centrifuge tests series is ongoing at the Technical University of Denmark (DTU). This paper will present some of the tests carried out with a focus on the influence of accumulation of rotation when changing...... the loading conditions. In these tests the load conditions are controlled by two load characteristics, one controlling the level of the cyclic loading and one controlling the characteristic of the cyclic loading. The centrifuge tests were performed in dense dry sand on a pile with prototype dimensions...

  10. Influence of cyclic torsional preloading on cyclic fatigue resistance of nickel - titanium instruments.

    Science.gov (United States)

    Pedullà, E; Lo Savio, F; Boninelli, S; Plotino, G; Grande, N M; Rapisarda, E; La Rosa, G

    2015-11-01

    To evaluate the effect of different torsional preloads on cyclic fatigue resistance of endodontic rotary instruments constructed from conventional nickel-titanium (NiTi), M-Wire or CM-Wire. Eighty new size 25, 0.06 taper Mtwo instruments (Sweden & Martina), size 25, 0.06 taper HyFlex CM (Coltene/Whaledent, Inc) and X2 ProTaper Next (Dentsply Maillefer) were used. The Torque and distortion angles at failure of new instruments (n = 10) were measured, and 0% (n = 10), 25%, 50% and 75% (n = 20) of the mean ultimate torsional strength as preloading condition were applied according to ISO 3630-1 for each brand. The twenty files tested for every extent of preload were subjected to 20 or 40 torsional cycles (n = 10). After torsional preloading, the number of cycles to failure was evaluated in a simulated canal with 60° angle of curvature and 5 mm of radius of curvature. Data were analysed using two-way analysis of variance. The fracture surface of each fragment was examined with a scanning electron microscope (SEM). Data were analysed by two-way analyses of variance. Preload repetitions did not influence the cyclic fatigue of the three brands; however, the 25%, 50% and 75% torsional preloading significantly reduced the fatigue resistance of all instruments tested (P 0.05). Torsional preloads reduced the cyclic fatigue resistance of conventional and treated (M-wire and CM-wire) NiTi rotary instruments except for size 25, 0.06 taper HyFlex CM instruments with a 25% of torsional preloading. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  11. Cyclic response and early damage evolution in multiaxial cyclic loading of 316L austenitic steel

    Czech Academy of Sciences Publication Activity Database

    Mazánová, Veronika; Škorík, Viktor; Kruml, Tomáš; Polák, Jaroslav

    2017-01-01

    Roč. 100, JUL (2017), s. 466-476 ISSN 0142-1123 R&D Projects: GA MŠk LM2015069; GA MŠk(CZ) LQ1601; GA ČR(CZ) GA13-23652S; GA ČR GA15-08826S Institutional support: RVO:68081723 Keywords : 316L steel * Crack initiation * Cyclic plasticity * Damage mechanism * Multiaxial straining Subject RIV: JL - Materials Fatigue, Friction Mechanics OBOR OECD: Audio engineering, reliability analysis Impact factor: 2.899, year: 2016

  12. 5 CFR 532.305 - Dominant industry.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Dominant industry. 532.305 Section 532... SYSTEMS Determining Rates for Principal Types of Positions § 532.305 Dominant industry. (a)(1) A specialized industry is a “dominant industry” if the number of wage employees in the wage area who are subject...

  13. Dominant limb asymmetry associated with prospective injury ...

    African Journals Online (AJOL)

    The purpose of the study was to identify associations between dominant lower limb asymmetry in unanticipated agility performance and prospective injury occurrence. Female netball players (N=24) performed unanticipated 180° turn agility sprints on both the dominant and non-dominant legs interspersed with an additional ...

  14. Co-Roman domination in graphs

    Indian Academy of Sciences (India)

    The basic complexity question of the decision problem for the co-Roman domination number takes the following form: Co-Roman Domination (CRDM). Instance. A nontrivial connected graph G = (V,E) and a positive integer k. Question. Does G have a co-Roman dominating function f with w(f ) ≤ k? We proceed to prove that ...

  15. Opposite effects of different hexachlorocyclohexane (lindane) isomers on cerebellar cyclic GMP: relation of cyclic GMP accumulation to seizure activity

    International Nuclear Information System (INIS)

    Fishman, B.E.; Gianutsos, G.

    1987-01-01

    A number of different depressant and convulsant agents have been shown to alter accumulation of cerebellar cyclic GMP. Since the different hexachlorocyclohexane (HCH) isomers elicit different pharmacological responses in mammals, the authors examined their effects on the accumulation of cerebellar cyclic GMP. Mice received one of the HCH isomers and were sacrificed for determination of cyclic GMP concentrations one hour later. Gamma-HCH increased cyclic GMP while alpha and delta -HCH decreased it. In addition, alpha and delta -HCH prevented the increase in cyclic GMP due to the gamma isomer. Picrotoxin increased cyclic GMP in a manner similar to that of gamma-HCH while strychnine produced only a small increase. All three HCH isomers inhibited the binding of 3 H-TBOB (a ligand for the GABA-A-receptor linked chloride channel) in mouse cerebellum. It is concluded the different HCH isomers can have different effects on cerebellar cyclic GMP accumulation and that these effects may mediated through actions at the GABA-A receptor linked chloride channel. 15 references, 1 figure, 3 tables

  16. Epigenetic dominance of prion conformers.

    Directory of Open Access Journals (Sweden)

    Eri Saijo

    2013-10-01

    Full Text Available Although they share certain biological properties with nucleic acid based infectious agents, prions, the causative agents of invariably fatal, transmissible neurodegenerative disorders such as bovine spongiform encephalopathy, sheep scrapie, and human Creutzfeldt Jakob disease, propagate by conformational templating of host encoded proteins. Once thought to be unique to these diseases, this mechanism is now recognized as a ubiquitous means of information transfer in biological systems, including other protein misfolding disorders such as those causing Alzheimer's and Parkinson's diseases. To address the poorly understood mechanism by which host prion protein (PrP primary structures interact with distinct prion conformations to influence pathogenesis, we produced transgenic (Tg mice expressing different sheep scrapie susceptibility alleles, varying only at a single amino acid at PrP residue 136. Tg mice expressing ovine PrP with alanine (A at (OvPrP-A136 infected with SSBP/1 scrapie prions propagated a relatively stable (S prion conformation, which accumulated as punctate aggregates in the brain, and produced prolonged incubation times. In contrast, Tg mice expressing OvPrP with valine (V at 136 (OvPrP-V136 infected with the same prions developed disease rapidly, and the converted prion was comprised of an unstable (U, diffusely distributed conformer. Infected Tg mice co-expressing both alleles manifested properties consistent with the U conformer, suggesting a dominant effect resulting from exclusive conversion of OvPrP-V136 but not OvPrP-A136. Surprisingly, however, studies with monoclonal antibody (mAb PRC5, which discriminates OvPrP-A136 from OvPrP-V136, revealed substantial conversion of OvPrP-A136. Moreover, the resulting OvPrP-A136 prion acquired the characteristics of the U conformer. These results, substantiated by in vitro analyses, indicated that co-expression of OvPrP-V136 altered the conversion potential of OvPrP-A136 from the S to

  17. The Chemistry of Cyclic All-Nitrogen Molecules

    National Research Council Canada - National Science Library

    Wodtke, Alec M

    2006-01-01

    ..., $474,927, February 15, 2004 - December 31, 2006. During this period, we have extended our preliminary investigations of azide photochemistry, with the aim of demonstrating unambiguously the photochemical production of cyclic-N, and of revealing...

  18. Riboflavin in cyclic vomiting syndrome: efficacy in three children.

    Science.gov (United States)

    Martinez-Esteve Melnikova, Anastasia; Schäppi, Michela G; Korff, Christian

    2016-01-01

    Cyclic vomiting syndrome is an episodic disorder considered to be a migraine variant. Riboflavin is efficient in the prophylactic treatment of migraines in adults. We describe the effectiveness and tolerance of riboflavin treatment in three children with cyclic vomiting syndrome. All of them fulfilled the diagnosis criteria for cyclic vomiting syndrome. They received prophylactic monotherapy with riboflavin for at least 12 months. Excellent response and tolerability was observed. Based on clinical observation in three cases, riboflavin may be an effective and safe prophylactic treatment for children with cyclic vomiting syndrome. CVS is one of the "childhood periodic syndromes" classified as a migraine subtype by the International Headache Society. Riboflavin is currently used as a prophylactic treatment in patients with migraine. Riboflavin may be an effective and safe prophylactic treatment for children with CVS. Increasing doses of riboflavin and long periods of prophylaxis may be needed in some children..

  19. Monotonic and cyclic deformation behaviour of ultrafine-grained aluminium

    International Nuclear Information System (INIS)

    May, J.; Amberger, D.; Dinkel, M.; Hoeppel, H.W.; Goeken, M.

    2008-01-01

    The effect of the enhanced strain-rate sensitivity (SRS) of ultrafine-grained commercially pure aluminium Al 99.5 on the mechanical properties under monotonic as well as under cyclic loading was investigated. Compared with the conventional grain-sized counterpart, for the monotonic tests, a strongly enhanced strength combined with a high ductility was obtained, depending on the strain rate. The enhanced SRS also affects the cyclic deformation behaviour and the fatigue lives. At a lower strain rate shorter fatigue lives and a different cyclic hardening behaviour are observed. Microstructural changes during cyclic deformation are investigated by X-ray diffraction profile analysis. Based on the fatigue behaviour and the X-ray diffraction profile analysis, thermally activated annihilation processes of dislocations are regarded to be the relevant deformation mechanism leading to enhanced SRS and ductility

  20. Cyclical Cohabitation Among Unmarried Parents in Fragile Families.

    Science.gov (United States)

    Nepomnyaschy, Lenna; Teitler, Julien

    2013-10-01

    Building on past research suggesting that cohabitation is an ambiguous family form, the authors examined an understudied residential pattern among unmarried parents: cyclical cohabitation, in which parents have multiple cohabitation spells with each other. Using 9 years of panel data from the Fragile Families and Child Wellbeing Study ( N = 2,084), they found that 10% of all parents with nonmarital births, and nearly a quarter of those living together when the child is 9 years old, are cyclical cohabitors. Cyclically cohabiting mothers reported more material hardships than mothers in most other relationship patterns but also reported more father involvement with children. On all measures of child well-being, except grade retention, children of cyclically cohabiting parents fared no worse than children of stably cohabiting biological parents and did not differ significantly from any other group.

  1. INFLUENCE OF INTERMITTENT CYCLIC LOADING ON REINFORCED CONCRETE RESISTANCE MODEL

    Directory of Open Access Journals (Sweden)

    Vasyl Karpiuk

    2017-01-01

    Full Text Available This article describes the study of reinforced concrete span bending structures under conditions of high-level cyclic loading. Previous studies on the development of physical models of bending reinforced concrete element fatigue resistance, cyclic effect of lateral forces, and methods of calculation, are important and appropriate owing to certain features and the essential specificity of the mentioned loading type. These primarily include the nonlinearity of deformation, damage accumulation in the form of fatigue micro- and macro-cracks, and exhausting destruction of construction materials. In this paper, key expressions determining the endurance limits of concrete, longitudinal reinforcement, and anchoring longitudinal reinforcement, which contribute to endurance throughout the entire construction, are considered. Establishing a link between stresses in the elements and deformations in the element under conditions of cyclic loading action is of equal importance because of the presence of cyclic stress-induced creep deformation.

  2. The Cyclical Relationship Approach in Teaching Basic Accounting Principles.

    Science.gov (United States)

    Golen, Steven

    1981-01-01

    Shows how teachers can provide a more meaningful presentation of various accounting principles by illustrating them through a cyclical relationship approach. Thus, the students see the entire accounting relationship as a result of doing business. (CT)

  3. A Novel Cyclic Catalytic Reformer for Hydrocarbon Fuels, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposed Small Business Innovative Research (SBIR) Phase I addresses development of a compact reformer system based on a cyclic partial oxidation (POx)...

  4. Safety Discrete Event Models for Holonic Cyclic Manufacturing Systems

    Science.gov (United States)

    Ciufudean, Calin; Filote, Constantin

    In this paper the expression “holonic cyclic manufacturing systems” refers to complex assembly/disassembly systems or fork/join systems, kanban systems, and in general, to any discrete event system that transforms raw material and/or components into products. Such a system is said to be cyclic if it provides the same sequence of products indefinitely. This paper considers the scheduling of holonic cyclic manufacturing systems and describes a new approach using Petri nets formalism. We propose an approach to frame the optimum schedule of holonic cyclic manufacturing systems in order to maximize the throughput while minimize the work in process. We also propose an algorithm to verify the optimum schedule.

  5. Synthesis and Catalytic Activity of Two New Cyclic Tetraaza Ligands

    Directory of Open Access Journals (Sweden)

    Burkhard König

    2003-05-01

    Full Text Available Two new chiral cyclic tetraaza ligands were synthesized and characterized. Their catalytic activity was tested in the asymmetric addition of diethylzinc to benzaldehyde. The expected secondary alcohol was obtained in moderate yields, but with very low enantioselectivity.

  6. Cyclical mastalgia: Prevalence and associated determinants in Hamadan City, Iran

    Directory of Open Access Journals (Sweden)

    Fatemeh Shobeiri

    2016-03-01

    Conclusions: Most of women with breast discomfort suffered cyclical mastalgia which severity can be determined by advanced age, age of marriage, history of abortion and history of premenstrual syndrome, but inversely by oral contraceptive use and exercise activity.

  7. Association of Marijuana Use and Cyclic Vomiting Syndrome

    Directory of Open Access Journals (Sweden)

    Mithun B. Pattathan

    2012-06-01

    Full Text Available Cannabis use has become one of the most commonly abused drugs in the world. It is estimated that each year 2.6 million individuals in the USA become new users and most are younger than 19 years of age. Reports describe marijuana use as high as 40–50% in male Cyclic Vomiting Syndrome patients. It is this interest in cannabis in the World, coupled with recognition of a cyclic vomiting illness associated with its chronic use that beckons a review of the most current articles, as well as a contribution from our own experiences in this area. The similarities we have demonstrated for both cannibinoid hyperemesis syndrome and cyclic vomiting make the case that cannibinoid hyperemesis syndrome is a subset of patients who have the diagnoses of cyclic vomiting syndrome and the role of marijuana should always be considered in the diagnosis of CVS, particularly in males.

  8. Quantum Codes From Cyclic Codes Over The Ring R 2

    International Nuclear Information System (INIS)

    Altinel, Alev; Güzeltepe, Murat

    2016-01-01

    Let R 2 denotes the ring F 2 + μF 2 + υ 2 + μυ F 2 + wF 2 + μwF 2 + υwF 2 + μυwF 2 . In this study, we construct quantum codes from cyclic codes over the ring R 2 , for arbitrary length n, with the restrictions μ 2 = 0, υ 2 = 0, w 2 = 0, μυ = υμ, μw = wμ, υw = wυ and μ (υw) = (μυ) w. Also, we give a necessary and sufficient condition for cyclic codes over R 2 that contains its dual. As a final point, we obtain the parameters of quantum error-correcting codes from cyclic codes over R 2 and we give an example of quantum error-correcting codes form cyclic codes over R 2 . (paper)

  9. Cyclic viscoelasticity and viscoplasticity of polypropylene/clay nanocomposites

    DEFF Research Database (Denmark)

    Drozdov, Aleksey; Christiansen, Jesper de Claville; Hog Lejre, Anne-Lise

    2012-01-01

    Observations are reported in tensile relaxation tests under stretching and retraction on poly-propylene/clay nanocomposites with various contents of filler. A two-phase constitutive model is developed in cyclic viscoelasticity and viscoplasticity of hybrid nanocomposites. Adjustable parameters...

  10. Defense gene induction in tobacco by nitric oxide, cyclic GMP, and cyclic ADP-ribose.

    Science.gov (United States)

    Durner, J; Wendehenne, D; Klessig, D F

    1998-08-18

    Reactive oxygen species are believed to perform multiple roles during plant defense responses to microbial attack, acting in the initial defense and possibly as cellular signaling molecules. In animals, nitric oxide (NO) is an important redox-active signaling molecule. Here we show that infection of resistant, but not susceptible, tobacco with tobacco mosaic virus resulted in enhanced NO synthase (NOS) activity. Furthermore, administration of NO donors or recombinant mammalian NOS to tobacco plants or tobacco suspension cells triggered expression of the defense-related genes encoding pathogenesis-related 1 protein and phenylalanine ammonia lyase (PAL). These genes were also induced by cyclic GMP (cGMP) and cyclic ADP-ribose, two molecules that can serve as second messengers for NO signaling in mammals. Consistent with cGMP acting as a second messenger in tobacco, NO treatment induced dramatic and transient increases in endogenous cGMP levels. Furthermore, NO-induced activation of PAL was blocked by 6-anilino-5,8-quinolinedione and 1H-(1,2,4)-oxadiazole[4,3-a]quinoxalin-1-one, two inhibitors of guanylate cyclase. Although 6-anilino-5,8-quinolinedione fully blocked PAL activation, inhibition by 1H-(1,2,4)-oxadiazole[4, 3-a]quinoxalin-1-one was not entirely complete, suggesting the existence of cGMP-independent, as well as cGMP-dependent, NO signaling. We conclude that several critical players of animal NO signaling are also operative in plants.

  11. Paediatric cyclical Cushing's disease due to corticotroph cell hyperplasia.

    LENUS (Irish Health Repository)

    Noctor, E

    2015-06-01

    Cushing\\'s disease is very rare in the paediatric population. Although uncommon, corticotroph hyperplasia causing Cushing\\'s syndrome has been described in the adult population, but appears to be extremely rare in children. Likewise, cyclical cortisol hypersecretion, while accounting for 15 % of adult cases of Cushing\\'s disease, has only rarely been described in the paediatric population. Here, we describe a very rare case of a 13-year old boy with cyclical cortisol hypersecretion secondary to corticotroph cell hyperplasia.

  12. Microgravity changes in heart structure and cyclic-AMP metabolism

    Science.gov (United States)

    Philpott, D. E.; Fine, A.; Kato, K.; Egnor, R.; Cheng, L.

    1985-01-01

    The effects of microgravity on cardiac ultrastructure and cyclic AMP metabolism in tissues of rats flown on Spacelab 3 are reported. Light and electron microscope studies of cell structure, measurements of low and high Km phosphodiesterase activity, cyclic AMP-dependent protein kinase activity, and regulatory subunit compartmentation show significant deviations in flight animals when compared to ground controls. The results indicate that some changes have occurred in cellular responses associated with catecholamine receptor interactions and intracellular signal processing.

  13. Multiaxial elastoplastic cyclic loading of austenitic 316L steel

    Czech Academy of Sciences Publication Activity Database

    Mazánová, Veronika; Polák, Jaroslav; Škorík, Viktor; Kruml, Tomáš

    2017-01-01

    Roč. 11, č. 40 (2017), s. 162-169 ISSN 1971-8993 R&D Projects: GA ČR(CZ) GA13-23652S; GA MŠk LM2015069; GA MŠk(CZ) LQ1601; GA ČR GA15-08826S Institutional support: RVO:68081723 Keywords : 316L steel * Crack initiation * Cyclic stress-strain curve * Multiaxial cyclic loading Subject RIV: JL - Materials Fatigue, Friction Mechanics OBOR OECD: Audio engineering, reliability analysis

  14. Facile and Green Synthesis of Saturated Cyclic Amines.

    Science.gov (United States)

    Hameed, Arruje; Javed, Sadia; Noreen, Razia; Huma, Tayyaba; Iqbal, Sarosh; Umbreen, Huma; Gulzar, Tahsin; Farooq, Tahir

    2017-10-12

    Single-nitrogen containing saturated cyclic amines are an important part of both natural and synthetic bioactive compounds. A number of methodologies have been developed for the synthesis of aziridines, azetidines, pyrrolidines, piperidines, azepanes and azocanes. This review highlights some facile and green synthetic routes for the synthesis of unsubstituted, multisubstituted and highly functionalized saturated cyclic amines including one-pot, microwave assisted, metal-free, solvent-free and in aqueous media.

  15. SYNERGISTIC DEGRADATION OF DENTIN BY CYCLIC STRESS AND BUFFER AGITATION

    OpenAIRE

    Orrego, Santiago; Romberg, Elaine; Arola, Dwayne

    2015-01-01

    Secondary caries and non-carious lesions develop in regions of stress concentrations and oral fluid movement. The objective of this study was to evaluate the influence of cyclic stress and fluid movement on material loss and subsurface degradation of dentin within an acidic environment. Rectangular specimens of radicular dentin were prepared from caries-free unrestored 3rd molars. Two groups were subjected to cyclic cantilever loading within a lactic acid solution (pH=5) to achieve compressiv...

  16. Global optimization of cyclic Kannan nonexpansive mappings in ...

    African Journals Online (AJOL)

    Consider a self-mapping T defined on a union of two subsets A and B of a Banach space such that T(A) ⊆ B and T(B) ⊆ A. In this work we survey the existence of an optimal approximate solution, known as a best proximity point for a class of cyclic mappings, called cyclic Kannan nonexpansive mappings, in Banach spaces ...

  17. Facile and Green Synthesis of Saturated Cyclic Amines

    Directory of Open Access Journals (Sweden)

    Arruje Hameed

    2017-10-01

    Full Text Available Single-nitrogen containing saturated cyclic amines are an important part of both natural and synthetic bioactive compounds. A number of methodologies have been developed for the synthesis of aziridines, azetidines, pyrrolidines, piperidines, azepanes and azocanes. This review highlights some facile and green synthetic routes for the synthesis of unsubstituted, multisubstituted and highly functionalized saturated cyclic amines including one-pot, microwave assisted, metal-free, solvent-free and in aqueous media.

  18. The role of opportunistic migration in cyclic games.

    Directory of Open Access Journals (Sweden)

    Pierre Buesser

    Full Text Available We study cyclic evolutionary games in a spatial diluted grid environment in which agents strategically interact locally but can also opportunistically move to other positions within a given migration radius. We find that opportunistic migration can inverse the cyclic prevalence between the strategies when the frequency of random imitation is large enough compared to the payoff-driven imitation. At the transition the average size of the patterns diverges and this threatens diversity of strategies.

  19. Similarity analysis, synthesis, and bioassay of antibacterial cyclic peptidomimetics

    Directory of Open Access Journals (Sweden)

    Workalemahu M. Berhanu

    2012-07-01

    Full Text Available The chemical similarity of antibacterial cyclic peptides and peptidomimetics was studied in order to identify new promising cyclic scaffolds. A large descriptor space coupled with cluster analysis was employed to digitize known antibacterial structures and to gauge the potential of new peptidomimetic macrocycles, which were conveniently synthesized by acylbenzotriazole methodology. Some of the synthesized compounds were tested against an array of microorganisms and showed antibacterial activity against Bordetella bronchistepica, Micrococcus luteus, and Salmonella typhimurium.

  20. Comparison Of INAA Methods (Long Conventional, Cyclic And Pseudo-Cyclic) For The Determination Of Se In Biological Samples

    International Nuclear Information System (INIS)

    Sarheel, A.

    2004-01-01

    Selenium content in serum blood, sample were received from international comparison programme (SABC) has been determined by Cyclic irradiation, pseudo-cyclic irradiation and long irradiation conventional Instrumental neutron activation analysis through the 162 keV gamma ray of the 77m Se nuclide for both cyclic and pseudo-cyclic and 264 keV gamma ray of 75 Se nuclide for conventional (long irradiation). The CINAA involve irradiation of samples for 20 s, decay for 15 s and counting for 20 s, samples recycling four times to improve the precision. The PCINAA involve irradiation of samples for 20 s, decay for 20 s and counting for 30s, samples recycling four times day by day. The Conventional (long irradiation) involve irradiation of samples for 20 hr (1 week), decay for 4 weeks and counting for 20 hr. The accuracy has been evaluated by analyzing the certified reference materials. (Author)

  1. Effect of cyclic torsional preloading on cyclic fatigue resistance of ProTaper Next and Mtwo nickel–titanium instruments

    Directory of Open Access Journals (Sweden)

    Eugenio Pedullà

    2015-06-01

    Conclusions: Torsional preloads reduced the cyclic fatigue resistance of M-wire and conventional (as ProTaper Next and Mtwo NiTi rotary instruments except for Mtwo with 25% or 50% of torsional preloading.

  2. Circulant Arrays on Cyclic Subgroups of Finite Fields: Rank Analysis and Construction of Quasi-Cyclic LDPC Codes

    OpenAIRE

    Zhang, Li; Lin, Shu; Abdel-Ghaffar, Khaled; Ding, Zhi; Zhou, Bo

    2010-01-01

    This paper consists of three parts. The first part presents a large class of new binary quasi-cyclic (QC)-LDPC codes with girth of at least 6 whose parity-check matrices are constructed based on cyclic subgroups of finite fields. Experimental results show that the codes constructed perform well over the binary-input AWGN channel with iterative decoding using the sum-product algorithm (SPA). The second part analyzes the ranks of the p...

  3. Effect of Surgical Removal of Endometriomas on Cyclic and Non-cyclic Pelvic Pain

    Directory of Open Access Journals (Sweden)

    Murat Api

    2015-07-01

    Full Text Available Background: Endometriosis is a complex disease with a spectrum of pain symptoms from mild dysmenorrhea to debilitating pelvic pain. There is no concrete evidence in the literature whether endometriotic cyst per se, causes pain spectrum related to the disease. The aim of the present study was to evaluate the effect of surgical removal of endometriomas on pain symptoms. Materials and Methods: In this prospective, observational, before-after study, which was conducted between March 2012 and January 2013 in Training and Research Hospital,Adana, Turkey, a total of 23 patients including 16 sexually active and 7 virgin symptomatic women were questioned for non-cyclic pelvic pain (NCPP, intensity of the NCPP, presence of cyclic dysmenorrhea, and dyspareunia before and after the endometrioma operation. Participants who were sonographically diagnosed and later pathologically confirmed as having endometrioma without sign and symptoms of deep infiltrative endometriosis (DIE were also questioned for pain symptoms before and after the laparoscopic removal of cyst wall. Patients with intraabdominal adhesions, history of pelvic inflammatory disease, and pathological diagnosis other than endometrioma were excluded. No ancillary procedures were applied for pain management, but if pain was present, pelvic peritoneal endometriotic lesions were ablated beside the removal of ovarian endometriotic cysts. Results: Out of 23 cases with endometrioma, 91 and 78% reported to have NCPP and dysmenorrhea, respectively, before the operation, while 60 and 48%, respectively, after the operation (McNemar’s test, P=0.016 for both figures. Among the sexually active cases, 31% (5/16 had dyspareunia before the operation and only 1 case reported the pain relief after the operation (McNemar’s test, P=1. Intensity of NCPP were reported to be none (8.7%, moderate (21.7%, severe (56.5% and unbearable (13% before the operation and decreased to none (43.5%, mild (43.5%, moderate (4

  4. Incipiently drowned platform deposit in cyclic Ordovician shelf sequence: Lower Ordovician Chepultepec Formation, Virginia

    Energy Technology Data Exchange (ETDEWEB)

    Bova, J.A.; Read, J.F.

    1983-03-01

    The Chepultepec interval, 145 to 260 m (476 to 853 ft) thick, in Virginia contains the Lower Member up to 150 m (492 ft) thick, and the Upper Member, up to 85 m (279 ft) thick, of peritidal cyclic limestone and dolomite, and a Middle Member, up to 110 m (360 ft) thick, of subtidal limestone and bioherms, passing northwestward into cyclic facies. Calculated long term subsidence rates were 4 to 5 cm/1000 yr (mature passive margin rates), shelf gradients were 6 cm/km, and average duration of cycles was 140,00 years. Peritidal cyclic sequences are upward shallowing sequences of pellet-skeletal limestone, thrombolites, rippled calcisiltites and intraclast grainstone, and laminite caps. They formed by rapid transgression with apparent submergence increments averaging approximately 2 m (6.5 ft) in Lower Member and 3.5 m (11.4 ft), Upper Member. Deposition during Middle Member time was dominated by skeletal limestone-mudstone, calcisiltite with storm generated fining-upward sequences, and burrow-mixed units that were formed near fair-weather wave base, along with thrombolite bioherms. Locally, there are upward shallowing sequences, of basal wackestone/mudstone to calcisiltite to bioherm complexes (locally with erosional scalloped tops). Following each submergence, carbonate sedimentation was able to build to sea level prior to renewed submergence. Large submergence events caused tidal flats to be shifted far to the west, and they were unable to prograde out onto the open shelf because of insufficient time before subsidence was renewed, and because the open shelf setting inhibited tidal flat deposition. The Middle Member represents an incipiently drowned sequence that developed by repeated submergence events.

  5. Third party cord blood transplant boosts autologous hematopoiesis in a case of persistent bone marrow aplasia after double transplant failure for β-thalassemia major

    Directory of Open Access Journals (Sweden)

    Giuseppe Visani

    2013-04-01

    Full Text Available A 9-year-old female received a double allogeneic stem cell transplant (SCT from an ABO-incompatible HLA-matched sibling for β-thalassemia major, without achieving a complete donor chimerism. Subsequently, the patient received autologous SCT and five donor lymphocyte infusion, without increasing donor chimerism. After the double transplant failure, we performed an unrelated transplant from a full-matched umbilical cord blood (UCBT. Due to the severe immunosuppression of the patient, we did not administer any conditioning regimen nor GVHD prophylaxis. On day +40 after UCBT, trilinear engraftment was documented. Surprisingly, the hematopoietic reconstitution was related to the re-expansion of the autologous (β-thalassemic hematopoietic stem cell, as documented by chimerism studies on both peripheral blood and bone marrow. At present, 30 months after UCBT, there is stable hematopoietic autologous reconstitution. This is the first description of the restoration of autologous hematopoiesis obtained with cord blood infusion in a thalassemia-major patient after a double transplant failure.

  6. EXEL-8232, a small-molecule JAK2 inhibitor, effectively treats thrombocytosis and extramedullary hematopoiesis in a murine model of myeloproliferative neoplasm induced by MPLW515L.

    Science.gov (United States)

    Wernig, G; Kharas, M G; Mullally, A; Leeman, D S; Okabe, R; George, T; Clary, D O; Gilliland, D G

    2012-04-01

    About 10% of patients with essential thrombocythemia (ET) or myelofibrosis (MF) that lack mutations in JAK2 harbor an activating mutation in the thrombopoietin receptor, MPLW515L. Distinct from the JAK2V617F retroviral transplant model, the MPLW515L model recapitulates many features of ET and MF, including severe fibrosis and thrombocytosis. We have tested EXEL-8232, an experimental potent JAK2 inhibitor, for efficacy in suppression of thrombocytosis in vivo and for its ability to attenuate MPLW515L myeloproliferative disease. EXEL-8232 was administered for 28 days q12 h by oral gavage at doses of 30 or 100 mg/kg, prospectively. Animals treated with EXEL-8232 at 100 mg/kg had normalized high platelet counts, eliminated extramedullary hematopoiesis in the spleen and eliminated bone marrow fibrosis, whereas the wild-type controls did not develop thrombocytopenia. Consistent with a clinical response in this model, we validated surrogate end points for response to treatment, including a reduction of endogenous colony growth and signaling inhibition in immature erythroid and myeloid primary cells both in vitro and upon treatment in vivo. We conclude that EXEL-8232 has efficacy in treatment of thrombocytosis in vivo in a murine model of ET and MF, and may be of therapeutic benefit for patients with MPL-mutant MPN.

  7. The Role of Cyclic Nucleotide Signaling Pathways in Cancer: Targets for Prevention and Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Fajardo, Alexandra M.; Piazza, Gary A. [Drug Discovery Research Center, Mitchell Cancer Institute, University of South Alabama, 1660 Springhill Ave, Suite 3029, Mobile, AL 36604 (United States); Tinsley, Heather N., E-mail: htinsley@montevallo.edu [Department of Biology, Chemistry, and Mathematics, University of Montevallo, Station 6480, Montevallo, AL 35115 (United States)

    2014-02-26

    For more than four decades, the cyclic nucleotides cyclic AMP (cAMP) and cyclic GMP (cGMP) have been recognized as important signaling molecules within cells. Under normal physiological conditions, cyclic nucleotides regulate a myriad of biological processes such as cell growth and adhesion, energy homeostasis, neuronal signaling, and muscle relaxation. In addition, altered cyclic nucleotide signaling has been observed in a number of pathophysiological conditions, including cancer. While the distinct molecular alterations responsible for these effects vary depending on the specific cancer type, several studies have demonstrated that activation of cyclic nucleotide signaling through one of three mechanisms—induction of cyclic nucleotide synthesis, inhibition of cyclic nucleotide degradation, or activation of cyclic nucleotide receptors—is sufficient to inhibit proliferation and activate apoptosis in many types of cancer cells. These findings suggest that targeting cyclic nucleotide signaling can provide a strategy for the discovery of novel agents for the prevention and/or treatment of selected cancers.

  8. A random search algorithm for cyclic delivery synchronization problem

    Directory of Open Access Journals (Sweden)

    Katarzyna Gdowska

    2017-09-01

    Full Text Available Background: The paper is devoted to the cyclic delivery synchronization problem with vehicles serving fixed routes. Each vehicle is assigned to a fixed route: the series of supplier’s and logistic centers to be visited one after another. For each route the service frequency is fixed and known in advance. A vehicle loads at a supplier’s, then it delivers goods to a logistic center and either loads other goods there and delivers them to the next logistic center along the route or goes to another logistic center. Each logistic center can belong to several routes, so goods are delivered there with one vehicle and then they departure for the further journey with another truck. The objective of this cyclic delivery synchronization problem is to maximize the total number of synchronizations of vehicles arrivals in logistic centers and their load times, so that it is possible to organize their arrivals in repeatable blocks. Methods: Basing on the previously developed mathematical model for the cyclic delivery synchronization problem we built a random search algorithm for cyclic delivery synchronization problem. The random heuristic search utilizes objective-oriented randomizing. In the paper the newly-developed random search algorithm for cyclic delivery synchronization problem is presented. Results: A computational experiment consisted of employing the newly-developed random search algorithm for solving a series of cyclic delivery synchronization problems. Results obtained with the algorithm were compared with solutions computed with the exact method. Conclusions: The newly-developed random search algorithm for cyclic delivery synchronization problem gives results which are considerably close to the ones obtained with mixed-integer programming. The main advantage of the algorithm is reduction of computing time; it is relevant for utilization of this method in practice, especially for large-sized problems.

  9. Autosomal dominant adult neuronal ceroid lipofuscinosis

    NARCIS (Netherlands)

    Nijssen, Peter C.G.

    2011-01-01

    this thesis investigates a family with autosomal dominant neuronal ceroid lipofuscinosis, with chapters on clinical neurology, neuropathology, neurogenetics, neurophysiology, auditory and visual aspects.

  10. Structural Diversity and Biological Activities of Fungal Cyclic Peptides, Excluding Cyclodipeptides

    OpenAIRE

    Xiaohan Wang; Minyi Lin; Dan Xu; Daowan Lai; Ligang Zhou

    2017-01-01

    Cyclic peptides are cyclic compounds formed mainly by the amide bonds between either proteinogenic or non-proteinogenic amino acids. This review highlights the occurrence, structures and biological activities of fungal cyclic peptides (excluding cyclodipeptides, and peptides containing ester bonds in the core ring) reported until August 2017. About 293 cyclic peptides belonging to the groups of cyclic tri-, tetra-, penta-, hexa-, hepta-, octa-, nona-, deca-, undeca-, dodeca-, tetradeca-, and ...

  11. Cyclic Stretch Alters Vascular Reactivity of Mouse Aortic Segments

    Directory of Open Access Journals (Sweden)

    Arthur Leloup

    2017-10-01

    Full Text Available Large, elastic arteries buffer the pressure wave originating in the left ventricle and are constantly exposed to higher amplitudes of cyclic stretch (10% than muscular arteries (2%. As a crucial factor for endothelial and smooth muscle cell function, cyclic stretch has, however, never been studied in ex vivo aortic segments of mice. To investigate the effects of cyclic stretch on vaso-reactivity of mouse aortic segments, we used the Rodent Oscillatory Tension Set-up to study Arterial Compliance (ROTSAC. The aortic segments were clamped at frequencies of 6–600 bpm between two variable preloads, thereby mimicking dilation as upon left ventricular systole and recoiling as during diastole. The preloads corresponding to different transmural pressures were chosen to correspond to a low, normal or high amplitude of cyclic stretch. At different time intervals, cyclic stretch was interrupted, the segments were afterloaded and isometric contractions by α1-adrenergic stimulation with 2 μM phenylephrine in the absence and presence of 300 μM L-NAME (eNOS inhibitor and/or 35 μM diltiazem (blocker of voltage-gated Ca2+ channels were measured. As compared with static or cyclic stretch at low amplitude (<10 mN or low frequency (0.1 Hz, cyclic stretch at physiological amplitude (>10 mN and frequency (1–10 Hz caused better ex vivo conservation of basal NO release with time after mounting. The relaxation of PE-precontracted segments by addition of ACh to stimulate NO release was unaffected by cyclic stretch. In the absence of basal NO release (hence, presence of L-NAME, physiological in comparison with aberrant cyclic stretch decreased the baseline tension, attenuated the phasic contraction by phenylephrine in the absence of extracellular Ca2+ and shifted the smaller tonic contraction more from a voltage-gated Ca2+ channel-mediated to a non-selective cation channel-mediated. Data highlight the need of sufficient mechanical activation of endothelial and

  12. Isothermal and cyclic oxidation resistance of pack siliconized Mo-Si-B alloy

    Science.gov (United States)

    Majumdar, Sanjib

    2017-08-01

    Oxidation behaviour of MoSi2 coated Mo-9Si-8B-0.75Y (at.%) alloy has been investigated at three critical temperatures including 750, 900 and 1400 °C in static air. Thermogravimetric analysis (TGA) data indicates a remarkable improvement in the oxidation resistance of the silicide coated alloy in both isothermal and cyclic oxidation tests. The cross-sectional scanning electron microscopy and energy dispersive spectroscopic analysis reveal the occurrence of internal oxidation particularly at the crack fronts formed in the outer MoSi2 layer during thermal cycling. The dominant oxidation mechanisms at 750-900 °C and 1400 °C are identified. Development of MoB inner layer further improves the oxidation resistance of the silicide coated alloy.

  13. Temperature Dependent Cyclic Deformation Mechanisms in Haynes 188 Superalloy

    Science.gov (United States)

    Rao, K. Bhanu Sankara; Castelli, Michael G.; Allen, Gorden P.; Ellis, John R.

    1995-01-01

    The cyclic deformation behavior of a wrought cobalt-base superalloy, Haynes 188, has been investigated over a range of temperatures between 25 and 1000 C under isothermal and in-phase thermomechanical fatigue (TMF) conditions. Constant mechanical strain rates (epsilon-dot) of 10(exp -3)/s and 10(exp -4)/s were examined with a fully reversed strain range of 0.8%. Particular attention was given to the effects of dynamic strain aging (DSA) on the stress-strain response and low cycle fatigue life. A correlation between cyclic deformation behavior and microstructural substructure was made through detailed transmission electron microscopy. Although DSA was found to occur over a wide temperature range between approximately 300 and 750 C the microstructural characteristics and the deformation mechanisms responsible for DSA varied considerably and were dependent upon temperature. In general, the operation of DSA processes led to a maximum of the cyclic stress amplitude at 650 C and was accompanied by pronounced planar slip, relatively high dislocation density, and the generation of stacking faults. DSA was evidenced through a combination of phenomena, including serrated yielding, an inverse dependence of the maximum cyclic hardening with epsilon-dot, and an instantaneous inverse epsilon-dot sensitivity verified by specialized epsilon-dot -change tests. The TMF cyclic hardening behavior of the alloy appeared to be dictated by the substructural changes occuring at the maximum temperature in the TMF cycle.

  14. Degradation forecast for PEMFC cathode-catalysts under cyclic loads

    Science.gov (United States)

    Moein-Jahromi, M.; Kermani, M. J.; Movahed, S.

    2017-08-01

    Degradation of Fuel Cell (FC) components under cyclic loads is one of the biggest bottlenecks in FC commercialization. In this paper, a novel experimental based algorithm is presented to predict the Catalyst Layer (CL) performance loss during cyclic load. The algorithm consists of two models namely Models 1 and 2. The Model 1 calculates the Electro-Chemical Surface Area (ECSA) and agglomerate size (e.g. agglomerate radius, rt,agg) for the catalyst layer under cyclic load. The Model 2 is the already-existing model from our earlier studies that computes catalyst performance with fixed structural parameters. Combinations of these two Models predict the CL performance under an arbitrary cyclic load. A set of parametric/sensitivity studies is performed to investigate the effects of operating parameters on the percentage of Voltage Degradation Rate (VDR%) with rank 1 for the most influential one. Amongst the considered parameters (such as: temperature, relative humidity, pressure, minimum and maximum voltage of the cyclic load), the results show that temperature and pressure have the most and the least influences on the VDR%, respectively. So that, increase of temperature from 60 °C to 80 °C leads to over 20% VDR intensification, the VDR will also reduce 1.41% by increasing pressure from 2 atm to 4 atm.

  15. Structure of a eukaryotic cyclic nucleotide-gated channel

    Science.gov (United States)

    Li, Minghui; Zhou, Xiaoyuan; Wang, Shu; Michailidis, Ioannis; Gong, Ye; Su, Deyuan; Li, Huan; Li, Xueming; Yang, Jian

    2018-01-01

    Summary Cyclic nucleotide-gated (CNG) channels are essential for vision and olfaction. They belong to the voltage-gated ion channel superfamily but their activities are controlled by intracellular cyclic nucleotides instead of transmembrane voltage. Here we report a 3.5 Å-resolution single-particle electron cryomicroscopy structure of a CNG channel from C. elegans in the cGMP-bound open state. The channel has an unusual voltage-sensor-like domain (VSLD), accounting for its deficient voltage dependence. A C-terminal linker connecting S6 and the cyclic nucleotide-binding domain interacts directly with both the VSLD and pore domain, forming a gating ring that couples conformational changes triggered by cyclic nucleotide binding to the gate. The selectivity filter is lined by the carboxylate side chains of a functionally important glutamate and three rings of backbone carbonyls. This structure provides a new framework for understanding mechanisms of ion permeation, gating and channelopathy of CNG channels and cyclic nucleotide modulation of related channels. PMID:28099415

  16. Cyclic creep and anelastic relaxation analysis of an ODS superalloy

    Science.gov (United States)

    Nardone, Vincent C.; Kimmerle, William L.; Tien, John K.

    1986-09-01

    This paper documents the effect of stress and temperature on the cyclic minimum strain rate at two different loading frequencies for the oxide dispersion strengthened (ODS) superalloy, INCONEL* MA 6000. The apparent stress exponent and activation energy for cyclic creep at both frequencies studied are shown to be greater than values observed for static creep. The large values of the stress exponent and activation energy for cyclic creep are proposed to result from anelastic strain storage delaying nonrecoverable creep during the on-load portion of the cyclic creep loading, such that the “effective stress” driving nonrecoverable creep is only a small fraction of the applied stress. In addition, the temperature dependence of the anelastic relaxation that occurs during the off-load portion of the cyclic creep loading is determined. The activation energy found for the relaxation process is equal to about one-half that for self-diffusion in nickel. A mechanism of localized climb of dislocations over the oxide dispersoids present in INCONEL MA 6000 is postulated to account for the observed activation energy of the relaxation process.

  17. Controlled cyclic stretch bioreactor for tissue-engineered heart valves.

    Science.gov (United States)

    Syedain, Zeeshan H; Tranquillo, Robert T

    2009-09-01

    A tissue-engineered heart valve (TEHV) represents the ultimate valve replacement, especially for juvenile patients given its growth potential. To date, most TEHV bioreactors have been developed based on pulsed flow of culture medium through the valve lumen to induce strain in the leaflets. Using a strategy for controlled cyclic stretching of tubular constructs reported previously, we developed a controlled cyclic stretch bioreactor for TEHVs that leads to improved tensile and compositional properties. The TEHV is mounted inside a latex tube, which is then cyclically pressurized with culture medium. The root and leaflets stretch commensurately with the latex, the stretching being dictated by the stiffer latex and thus controllable. Medium is also perfused through the lumen at a slow rate in a flow loop to provide nutrient delivery. Fibrin-based TEHVs prepared with human dermal fibroblasts were subjected to three weeks of cyclic stretching with incrementally increasing strain amplitude. The TEHV possessed the tensile stiffness and stiffness anisotropy of leaflets from sheep pulmonary valves and could withstand cyclic pulmonary pressures with similar distension as for a sheep pulmonary artery.

  18. Evolutive masing model, cyclic plasticity, ageing and memory effects

    International Nuclear Information System (INIS)

    Sidoroff, F.

    1987-01-01

    Many models are proposed for the mechanical description of the cyclic behaviour of metals and used for structure analysis under cyclic loading. Such a model must include two basic features: Dissipative behaviour on each cycle (hysteresis loop); evolution of this behaviour during the material's life (cyclic hardening or softening, aging,...). However, if both aspects are present in most existing models, the balance between them may be quite different. Many metallurgical investigations have been performed about the microstructure and its evolution during cyclic loading, and it is desirable to introduce these informations in phenomenological models. The evolutive Masing model has been proposed to combine: the accuracy of hereditary models for the description of hysteresis on each cycle, the versatility of internal variables for the state description and evolution, a sufficient microstructural basis to make the interaction easier with microstructural investigations. The purpose of the present work is to discuss this model and to compare different evolution assumptions with respect to some memory effects (cyclic hardening and softening, multilevel tests, aging). Attention is limited to uniaxial, rate independent elasto-plastic behaviour

  19. Thermal to Electric Energy Conversion for Cyclic Heat Loads

    Science.gov (United States)

    Whitehead, Benjamin E.

    Today, we find cyclic heat loads almost everywhere. When we drive our cars, the engines heat up while we are driving and cool while parked. Processors heat while the computer is in use at the office and cool when idle at night. The sun heats the earth during the day and the earth radiates that heat into space at night. With modern technology, we have access to a number of methods to take that heat and convert it into electricity, but, before selecting one, we need to identify the parameters that inform decision making. The majority of the parameters for most systems include duty cycle, total cost, weight, size, thermal efficiency, and electrical efficiency. However, the importance of each of these will depend on the application. Size and weight take priority in a handheld device, while efficiency dominates in a power plant, and duty cycle is likely to dominate in highly demanding heat pump applications. Over the past decade, developments in semiconductor technology has led to the creation of the thermoelectric generator. With no moving parts and a nearly endlessly scalable nature, these generators present interesting opportunities for taking advantage of any source of waste heat. However, these generators are typically only capable of 5-8% efficiency from conversion of thermal to electric energy. [1]. Similarly, advancements in photovoltaic cells has led to the development of thermophotovoltaics. By heating an emitter to a temperature so it radiates light, a thermophotovoltaic cell then converts that light into electricity. By selecting materials that emit light in the optimal ranges of the appropriate photovoltaic cells, thermophotovoltaic systems can potentially exceed the current maximum of 10% efficiency. [2]. By pressurizing certain metal powders with hydrogen, hydrogen can be bound to the metal, creating a metal hydride, from which hydrogen can be later re-extracted under the correct pressure and temperature conditions. Since this hydriding reaction is

  20. Autosomal dominant hereditary ataxia in Sri Lanka

    OpenAIRE

    Sumathipala, Dulika S; Abeysekera, Gayan S; Jayasekara, Rohan W; Tallaksen, Chantal ME; Dissanayake, Vajira HW

    2013-01-01

    Background Spinocerebellar ataxias (SCA) are a group of hereditary neurodegenerative disorders. Prevalence of SCA subtypes differ worldwide. Autosomal dominant ataxias are the commonest types of inherited ataxias seen in Sri Lanka. The aim of the study is to determine the genetic etiology of patients with autosomal dominant ataxia in Sri Lanka and to describe the clinical features of each genetic subtype. Methods ...

  1. Outer-2-independent domination in graphs

    Indian Academy of Sciences (India)

    independent dominating set of a graph is a set of vertices of such that every vertex of ()\\ has a neighbor in and the maximum vertex degree of the subgraph induced by ()\\ is at most one. The outer-2-independent domination ...

  2. Computation of term dominance in text documents

    Science.gov (United States)

    Bauer, Travis L [Albuquerque, NM; Benz, Zachary O [Albuquerque, NM; Verzi, Stephen J [Albuquerque, NM

    2012-04-24

    An improved entropy-based term dominance metric useful for characterizing a corpus of text documents, and is useful for comparing the term dominance metrics of a first corpus of documents to a second corpus having a different number of documents.

  3. Equivalence domination in graphs | Arumugam | Quaestiones ...

    African Journals Online (AJOL)

    Click on the link to view the abstract. Keywords: Equivalence domination, total domination, P3-forming set. Quaestiones Mathematicae 36(2013), 331-340. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.2989/16073606.2013.779959 · AJOL African ...

  4. Modelling dominance in a flexible intercross analysis

    Directory of Open Access Journals (Sweden)

    Besnier Francois

    2009-06-01

    Full Text Available Abstract Background The aim of this paper is to develop a flexible model for analysis of quantitative trait loci (QTL in outbred line crosses, which includes both additive and dominance effects. Our flexible intercross analysis (FIA model accounts for QTL that are not fixed within founder lines and is based on the variance component framework. Genome scans with FIA are performed using a score statistic, which does not require variance component estimation. Results Simulations of a pedigree with 800 F2 individuals showed that the power of FIA including both additive and dominance effects was almost 50% for a QTL with equal allele frequencies in both lines with complete dominance and a moderate effect, whereas the power of a traditional regression model was equal to the chosen significance value of 5%. The power of FIA without dominance effects included in the model was close to those obtained for FIA with dominance for all simulated cases except for QTL with overdominant effects. A genome-wide linkage analysis of experimental data from an F2 intercross between Red Jungle Fowl and White Leghorn was performed with both additive and dominance effects included in FIA. The score values for chicken body weight at 200 days of age were similar to those obtained in FIA analysis without dominance. Conclusion We have extended FIA to include QTL dominance effects. The power of FIA was superior, or similar, to standard regression methods for QTL effects with dominance. The difference in power for FIA with or without dominance is expected to be small as long as the QTL effects are not overdominant. We suggest that FIA with only additive effects should be the standard model to be used, especially since it is more computationally efficient.

  5. Crack shielding degradation in alumina during cyclic fatigue

    Energy Technology Data Exchange (ETDEWEB)

    El Attaoui, H.; Saadaoui, M. [LERSIM, Rabat (Morocco); INSA de Lyon, Villeurbanne (France). GEMPPM; Chevalier, J.; Fantozzi, G. [INSA de Lyon, Villeurbanne (France). GEMPPM

    2002-07-01

    R curve measurements before and after cyclic fatigue were performed on SENB specimens of coarse grain alumina to investigate fatigue effect. A significant drop of the crack growth resistance was observed after cyclic loading which could be associated to a decrease of the shielding effect due to bridging degradation. No variation was observed on the amount of degradation as the number of cycles increased for a maximum applied load, K{sub max} of 50% of the K{sub R} value before cyclic loading, K{sub f}, whereas an increase was observed for K{sub max}/K{sub f} = 0.7, when the critical number of cycles corresponding to failure was approached. (orig.)

  6. Cyclic AMP system in muscle tissue during prolonged hypokinesia

    Science.gov (United States)

    Antipenko, Y. A.; Bubeyev, Y. A.; Korovkin, B. F.; Mikhaleva, N. P.

    1980-01-01

    Components of the cyclic Adenosine-cyclic-35-monophosphate (AMP) system in the muscle tissue of white rats were studied during 70-75 days of hypokinesia, created by placing the animals in small booths which restricted their movements, and during the readaptation period. In the initial period, cyclic AMP levels and the activities of phosphodiesterase and adenylate cyclase in muscle tissue were increased. The values for these indices were roughly equal for controls and experimental animals during the adaptation period, but on the 70th day of the experiment cAMP levels dropped, phosphodiesterase activity increased, and the stimulative effect of epinephrine on the activity of adenylate cyclase decreased. The indices under study normalized during the readaptation period.

  7. Durability of Modified Expanded Polystyrene Concrete after Dynamic Cyclic Loading

    Directory of Open Access Journals (Sweden)

    Wenbo Shi

    2016-01-01

    Full Text Available EPS concrete was produced by mixing the expanded polystyrene spheres (EPS and polymer emulsion and thickener to the matrix concrete, and this concrete had good vibration energy absorption characteristics. Based on the experimental data obtained on EPS volume ratio of 0%, 20%, 30%, and 40% by replacing matrix or coarse aggregate, the two design styles had nearly the same compressive strength. By applying frequency of 5 Hz, 50000 or 100000 times, 40 KN, 50 KN, and 60 KN cyclic loading, it is shown that the higher the inclusion size was, the lower the compressive strength of the EPS concrete would be; the larger the applying dynamic cyclic load was, the more obvious the compressive strength changing would be. Meanwhile, the strength of EPS concrete had no evident change after durability test. The results of this research had practical significance on using EPS concrete in some long-term cyclic dynamic load engineering.

  8. Application Of Shakedown Analysis To Cyclic Creep Damage Limits

    Energy Technology Data Exchange (ETDEWEB)

    Carter, Peter [Stress Engineering Services Inc.; Jetter, Robert I [Consultant; Sham, Sam [ORNL

    2012-01-01

    Shakedown analysis may be used to provide a conservative estimate of local rupture and hence cyclic creep damage for use in a creep-fatigue assessment. The shakedown analysis is based on an elastic-perfectly plastic material with a temperature-dependent pseudo yield stress defined to guarantee that a shakedown solution exists which does not exceed rupture stress and temperature for a defined life. The ratio of design life to the estimated maximum cyclic life is the shakedown creep damage. The methodology does not require stress classification and is also applicable to cycles over the full range of temperature above and below the creep regime. Full cyclic creep and damage analysis is the alternative when shakedown analysis appears to be excessively conservative.

  9. Cyclicity of non-associative products on D-branes

    CERN Document Server

    Herbst, Manfred; Kreuzer, M

    2004-01-01

    The non-commutative geometry of deformation quantization appears in string theory through the effect of a B-field background on the dynamics of D-branes in the topological limit. For arbitrary backgrounds, associativity of the star product is lost, but only cyclicity is necessary for a description of the effective action in terms of a generalized product. In previous work we showed that this property indeed emerges for a non-associative product that we extracted from open string amplitudes in curved background fields. In the present note we extend our investigation through second order in a complete derivative expansion. We establish cyclicity with respect to the Born--Infeld measure and find a logarithmic correction that modifies the Kontsevich formula in an arbitrary background satisfying the generalized Maxwell equation. This equation is the physical equivalent of a divergence-free non-commutative parameter, which is required for cyclicity already in the associative case.

  10. Cyclicality and Firm Size in Private Firm Defaults

    DEFF Research Database (Denmark)

    Jensen, Thais Lærkholm; Lando, David; Medhat, Mamdouh

    2017-01-01

    The Basel II/III and CRD IV Accords reduce capital charges on bank loans to smaller firms by assuming that the default probabilities of smaller firms are less sensitive to macroeconomic cycles. We test this assumption in a default intensity framework using a large sample of bank loans to private...... Danish firms. We find that controlling only for size, the default probabilities of small firms are, in fact, less cyclical than the default probabilities of large firms. However, accounting for firm characteristics other than size, we find that the default probabilities of small firms are equally...... cyclical or even more cyclical than the default probabilities of large firms. These results hold using a multiplicative Cox model as well as an additive Aalen model with time-varying coefficients....

  11. Cyclic Tetrapyrrole Sulfonation, Metals, and Oligomerization in Antiprion Activity▿

    Science.gov (United States)

    Caughey, Winslow S.; Priola, Suzette A.; Kocisko, David A.; Raymond, Lynne D.; Ward, Anne; Caughey, Byron

    2007-01-01

    Cyclic tetrapyrroles are among the most potent compounds with activity against transmissible spongiform encephalopathies (TSEs; or prion diseases). Here the effects of differential sulfonation and metal binding to cyclic tetrapyrroles were investigated. Their potencies in inhibiting disease-associated protease-resistant prion protein were compared in several types of TSE-infected cell cultures. In addition, prophylactic antiscrapie activities were determined in scrapie-infected mice. The activity of phthalocyanine was relatively insensitive to the number of peripheral sulfonate groups but varied with the type of metal bound at the center of the molecule. The tendency of the various phthalocyanine sulfonates to oligomerize (i.e., stack) correlated with anti-TSE activity. Notably, aluminum(III) phthalocyanine tetrasulfonate was both the poorest anti-TSE compound and the least prone to oligomerization in aqueous media. Similar comparisons of iron- and manganese-bound porphyrin sulfonates confirmed that stacking ability correlates with anti-TSE activity among cyclic tetrapyrroles. PMID:17709470

  12. Cyclic tetrapyrrole sulfonation, metals, and oligomerization in antiprion activity.

    Science.gov (United States)

    Caughey, Winslow S; Priola, Suzette A; Kocisko, David A; Raymond, Lynne D; Ward, Anne; Caughey, Byron

    2007-11-01

    Cyclic tetrapyrroles are among the most potent compounds with activity against transmissible spongiform encephalopathies (TSEs; or prion diseases). Here the effects of differential sulfonation and metal binding to cyclic tetrapyrroles were investigated. Their potencies in inhibiting disease-associated protease-resistant prion protein were compared in several types of TSE-infected cell cultures. In addition, prophylactic antiscrapie activities were determined in scrapie-infected mice. The activity of phthalocyanine was relatively insensitive to the number of peripheral sulfonate groups but varied with the type of metal bound at the center of the molecule. The tendency of the various phthalocyanine sulfonates to oligomerize (i.e., stack) correlated with anti-TSE activity. Notably, aluminum(III) phthalocyanine tetrasulfonate was both the poorest anti-TSE compound and the least prone to oligomerization in aqueous media. Similar comparisons of iron- and manganese-bound porphyrin sulfonates confirmed that stacking ability correlates with anti-TSE activity among cyclic tetrapyrroles.

  13. Cyclic operation of power plant; Cyklisk drift av kraftvaermeverk

    Energy Technology Data Exchange (ETDEWEB)

    Storesund, Jan

    2007-12-15

    The great majority of power plants are designed for base load operation with a relatively small number of starts and stops per year. Therefore, there has been no need to consider fatigue at design. Over the last few years operation with more frequent starts and stops exists as a consequence of swinging electricity prices that has become common. This involves significantly higher frequency of damages; not least fatigue relates damages, and the number of severe failures in components that never before have had damage problems may increase as well. In the present work the different types of component that may suffer from cyclic operation related damage are gathered by a literature survey and described as follows: - where and how the damages comes up, - constructions that should be avoided, - non-destructive testing (NDT) for damage that may come up under cyclic operation, - calculation and assessment of integrity of critical components - areas where continued research would be valuable. Recommendations have been put together to be used to prevent cyclic operation related damage and to detect it in time. The target group for this study is i) plant owners of plants where cyclic operation is or may be present, ii) researchers in the area, and, iii) inspectors and NDT-operators. There are quite a number of components where cyclic operation has been found to significantly influence the lift time. Some of these components are described in many papers whereas occasional papers have been found for others. The amount of information that is possible to get for a certain component is likely related to its significance for cyclic operation damage. The most frequently reported problem is ligament cracking of high temperature headers. Other components where extensive studies have been done are: wall panels, creep-fatigue loaded welds and turbine components

  14. The Cyclic Sieving Phenomenon for Faces of Generalized Cluster Complexes

    OpenAIRE

    Eu, Sen-Peng; Fu, Tung-Shan

    2006-01-01

    The notion of cyclic sieving phenomenon is introduced by Reiner, Stanton, and White as a generalization of Stembridge's $q=-1$ phenomenon. The generalized cluster complexes associated to root systems are given by Fomin and Reading as a generalization of the cluster complexes found by Fomin and Zelevinsky. In this paper, the faces of various dimensions of the generalized cluster complexes in type $A_n$, $B_n$, $D_n$, and $I_2(a)$ are shown to exhibit the cyclic sieving phenomenon under a cycli...

  15. Photoelectron spectra and structures of three cyclic dipeptides

    DEFF Research Database (Denmark)

    Wickrama Arachchilage, A.P.; Wang, F.; Feyer, V.

    2012-01-01

    spectra of all three cyclic dipeptides agree reasonably well with the experimental spectra. The central ring and the side chains act as independent chromophores whose spectra do not influence one another, except for prolyl dipeptides, where the pyrrole ring is fused with the central ring. In this case......We have investigated the electronic structure of three cyclic dipeptides: cyclo(Histidyl-Glycyl) (cHisGly), cyclo(Tyrosyl-Prolyl) (cTyrPro), and cyclo(Phenylalanyl-Phenylalanyl) (cPhePhe) in the vapor phase, by means of photoemission spectroscopy and theoretical modeling. The last compound...

  16. Cyclic Plane Strain Compression Tests on Dense Granular Materials

    Science.gov (United States)

    Koseki, Junichi; Karimi, Job Munene; Tsutsumi, Yukika; Maqbool, Sajjad; Sato, Takeshi

    A series of cyclic plane strain compression tests are performed under drained condition on dense Toyoura sand and compacted Chiba gravel, by using small-scale and large-scale apparatuses, respectively. Comparisons are made with results from monotonic loading tests. Local strain distributions are calculated by conducting image analyses of digital photographs taken at different stages of loading during each test. Based on these results, strain localization properties of dense granular materials are discussed, in particular focusing on possible effects of cyclic loading history.

  17. Determination of silver using cyclic epithermal neutron activation analysis

    International Nuclear Information System (INIS)

    Pun, T.H.; Landsberger, S.

    2012-01-01

    A fast pneumatic transfer facility was installed in Nuclear Engineering Teaching Laboratory (NETL) of the University of Texas at Austin for the purpose of cyclic thermal and epithermal neutron activation analysis. In this study efforts were focused on the evaluation of cyclic epithermal neutron activation analysis (CENAA). Various NIST and CANMET certified materials were analyzed by the system. Experiment results showed 110 Ag with its 25 s half-life as one of the isotopes favored by the system. Thus, the system was put into practical application in identifying silver in metallic ores. Comparison of sliver concentrations as determined by CENAA in CANMET certified reference materials gave very good results. (author)

  18. Progressive buckling under both constant axial load and cyclic distortion

    International Nuclear Information System (INIS)

    Clement, G.; Acker, D.; Lebey, J.

    1988-09-01

    Thin structures submitted to compressive loads must be carefully designed to avoid any risk of ruin by buckling. The aim of this paper is, first, to evidence that the critical buckling load may be notably lowered when cyclic strains are added to the compressive load and, secondly, to propose a practical rule of prevention against the ruin due to the progressive buckling phenomenon. This rule is validated by the results of numerous tests related to the entire range of modes of buckling (i.e. from fully plastic to fully elastic). Practical cases of interest for its use could mainly be those where cyclic thermal stresses are involved

  19. Response of monopiles under cyclic lateral loading in sand

    DEFF Research Database (Denmark)

    Nicolai, Giulio; Ibsen, Lars Bo

    2015-01-01

    Currently the main design guidelines propose to reduce the lateral resistance of offshore piles when accounting for cyclic loading. The present work provides results from laboratory tests in which such reduction has not occurred. The experimental investigation is based on testing a small-scale mo......Currently the main design guidelines propose to reduce the lateral resistance of offshore piles when accounting for cyclic loading. The present work provides results from laboratory tests in which such reduction has not occurred. The experimental investigation is based on testing a small...

  20. Cyclic and Long-Term Variation of Sunspot Magnetic Fields

    Science.gov (United States)

    2014-10-15

    AFRL-RV-PS- TP-2014-0009 AFRL-RV-PS- TP-2014-0009 CYCLIC AND LONG-TERM VARIATION OF SUNSPOT MAGNETIC FIELDS Alexei A. Pevtsov, et al. 15...TITLE AND SUBTITLE Cyclic and Long-Term Variation of Sunspot Magnetic Fields 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62601F...from the Mount Wilson Observatory (MWO) were used to study the long-term variations of sunspot field strengths from 1920 to 1958. Following a modified

  1. Hand dominance in upper extremity musculoskeletal disorders.

    Science.gov (United States)

    Shiri, Rahman; Varonen, Helena; Heliövaara, Markku; Viikari-Juntura, Eira

    2007-05-01

    To investigate the role of hand dominance in common upper extremity musculoskeletal disorders (UEMSD) in a population study. The target population consisted of a representative sample of people aged 30 years or older residing in Finland during 2000-2001. Of the 7977 eligible subjects, 6254 (78.4%) were included in the study. The prevalence of UEMSD was as follows: rotator cuff tendinitis 3.8%, bicipital tendinitis 0.5%, lateral epicondylitis 1.1%, medial epicondylitis 0.3%, carpal tunnel syndrome (CTS) 3.8%, and surgery due to CTS 1.3%. CTS was 2.5 times as prevalent in women as men, whereas the other UEMSD were as common in both sexes. Rotator cuff and bicipital tendinitis and medial epicondylitis were more prevalent in the dominant arm only in women, whereas lateral epicondylitis was more prevalent in the dominant elbow in both sexes. The higher prevalence of rotator cuff and bicipital tendinitis in the dominant side persisted beyond working age. The prevalence of CTS did not differ by hand dominance. Dominant hand had been operated more frequently for CTS in women. Our findings show that UEMSD are more prevalent in the dominant than nondominant arm mainly in women. For shoulder tendinitis, the difference persists throughout adult age. Physical load factors may have long-lasting effects on the shoulder and they may play a greater role in women than men.

  2. Photosynthesis in Hydrogen-Dominated Atmospheres

    OpenAIRE

    Bains, William; Seager, Sara; Zsom, Andras

    2014-01-01

    The diversity of extrasolar planets discovered in the last decade shows that we should not be constrained to look for life in environments similar to early or present-day Earth. Super-Earth exoplanets are being discovered with increasing frequency, and some will be able to retain a stable, hydrogen-dominated atmosphere. We explore the possibilities for photosynthesis on a rocky planet with a thin H[subscript 2]-dominated atmosphere. If a rocky, H[subscript 2]-dominated planet harbors life, th...

  3. Extended Chain of Domination Parameters in Graphs

    OpenAIRE

    Hamid, I. Sahul; Balamurugan, S.

    2013-01-01

    A subset S of the vertex set V(G) of a graph G is called an isolate set if the subgraph induced by S has an isolated vertex. The subset S is called an isolate dominating set if it is both isolate and dominating. Also, S is called an isolate irredundant set if it is both isolate and irredundant. In this paper, we establish a chain connecting various isolate parameters with the existing domination parameters and discuss equality among the parameters in the extended chain.

  4. Pinwheel Stabilization by Ocular Dominance Segregation

    Science.gov (United States)

    Reichl, Lars; Löwel, Siegrid; Wolf, Fred

    2009-05-01

    We present an analytical approach for studying the coupled development of ocular dominance and orientation preference columns. Using this approach we demonstrate that ocular dominance segregation can induce the stabilization and even the production of pinwheels by their crystallization in two types of periodic lattices. Pinwheel crystallization depends on the overall dominance of one eye over the other, a condition that is fulfilled during early cortical development. Increasing the strength of intermap coupling induces a transition from pinwheel-free stripe solutions to intermediate and high pinwheel density states.

  5. Impact of chromosome alterations, genetic mutations and clonal hematopoiesis of indeterminate potential (CHIP) on the classification and risk stratification of MDS.

    Science.gov (United States)

    Ganguly, Bani Bandana; Banerjee, Debasis; Agarwal, Mohan B

    2018-03-01

    The advent of technological development has undoubtedly advanced biological and molecular inputs for better understanding the heterogeneous hematopoietic pre-malignant disorder of the stem cells known as myelodysplastic syndromes (MDS). Chromosomal rearrangements, including del(3q/5q/7q/11q/12p/20q), loss of 5/7/Y, trisomy 8/19, i(17q), etc. frequently detected in MDS with variable frequencies and combinations, are the integral components of the 5-tier risk-stratification and WHO-2016 classification. Observations on mutations in genes involved in RNA-splicing, DNA methylation, chromatin modification, transcription factor, signal transduction/kinases, RAS pathway, cohesin complex, DNA repair and other pathways have given insights in independent effects and biological interaction of co-occurrence on disease-phenotype and treatment outcome. However, recent concepts of clonal hematopoiesis of indeterminate potential (CHIP) and idiopathic cytopenia of undetermined significance (ICUS) have urged a re-definition of mutational events in non-clonal cytopenia and non-MDS healthy elderly but with a higher risk of overt leukemia. Considering gene mutations, chromosomal alterations, CHIP, ICUS and their significance in classification and risk-scoring certainly presents a comprehensive picture of disease-phenotype towards better understanding of MDS-pathogenesis, its evolution to AML and its response to therapeutic agents. The present review summarizes chromosomal and gene mutations, co-existence of mutational complexity, and WHO-2016 classification and risk-stratifications of MDS to facilitate a better understanding of its pathogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Apoptotic Cell Localization in Preantral and Antral Follicles in Relation to Non-cyclic and Cyclic Gilts.

    Science.gov (United States)

    Phoophitphong, D; Srisuwatanasagul, S; Koonjaenak, S; Tummaruk, P

    2016-06-01

    The objective of this study was to determine apoptotic cell localization in preantral and antral follicles of porcine ovaries. Additionally, the proportion of cells undergoing apoptosis was also compared between delayed puberty gilts and normal cyclic gilts. Ovarian tissues were obtained from 34 culled gilts with age and weight of 270.1 ± 3.9 days and 143.8 ± 2.4 kg, respectively. The gilts were classified according to their ovarian appearance as 'non-cyclic' (n = 7) and 'cyclic' (n = 27) gilts. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay was used to determine apoptotic cell expression in different compartments of the ovarian tissue sections. All apparent preantral (n = 110) and antral (n = 262) follicles were evaluated using image analysis software. It was found that apoptotic cells were expressed in both granulosa (22.2%) and theca cell layers (21.3%) of the follicles in the porcine ovaries. The proportion of apoptotic cells in the granulosa layer in the follicles was positively correlated with that in the theca layer (r = 0.90, p  0.05) or theca cell layers (28.6% and 26.5%, p > 0.05). The proportion of apoptotic cells in non-cyclic gilts was higher than cyclic gilts in both granulosa (31.7% and 22.6%, p gilts than cyclic gilts. This implied that apoptosis could be used as a biologic marker for follicular development/function and also that apoptosis was significantly associated with anoestrus or delayed puberty in gilts, commonly observed in tropical climates. © 2016 Blackwell Verlag GmbH.

  7. Nearly Cyclic Pursuit and its Hierarchical variant for Multi-agent Systems

    DEFF Research Database (Denmark)

    Iqbal, Muhammad; Leth, John-Josef; Ngo, Trung Dung

    2015-01-01

    The rendezvous problem for multiple agents under nearly cyclic pursuit and hierarchical nearly cyclic pursuit is discussed in this paper. The control law designed under nearly cyclic pursuit strategy enables the agents to converge at a point dictated by a beacon. A hierarchical version of the nea......The rendezvous problem for multiple agents under nearly cyclic pursuit and hierarchical nearly cyclic pursuit is discussed in this paper. The control law designed under nearly cyclic pursuit strategy enables the agents to converge at a point dictated by a beacon. A hierarchical version...

  8. Experimental study under uniaxial cyclic behavior at room and high temperature of 316L stainless steel

    International Nuclear Information System (INIS)

    Kang Guozheng; Gao Qing; Yang Xianjie; Sun Yafang

    2001-01-01

    An experimental study was carried out of the cyclic properties of 316L stainless steel subjected to uniaxial strain and stress at room and high temperature. The effects of cyclic strain amplitude, temperature and their histories on the cyclic deformation behavior of 316L stainless steel are investigated. And, the influences of stress amplitude, mean stress, temperature and their histories on ratcheting are also analyzed. It is shown that either uniaxial cyclic property under cyclic strain or ratcheting under asymmetric uniaxial cyclic stress depends not only on the current temperature and loading state, but also on the previous temperature and loading history. Some significant results are obtained

  9. Cyclic and heteroclinic flows near general static spherically symmetric black holes: semi-cyclic flows - addendum and corrigendum

    Energy Technology Data Exchange (ETDEWEB)

    Azreg-Ainou, Mustapha [Baskent University, Engineering Faculty, Ankara (Turkey)

    2017-01-15

    We present new accretion solutions of a polytropic perfect fluid onto an f(R)-gravity de Sitter-like black hole. We consider two f(R)-gravity models and obtain finite-period cyclic flows oscillating between the event and cosmological horizons as well as semi-cyclic critical flows executing a two-way motion from and back to the same horizon. Besides the generalizations and new solutions presented in this work, a corrigendum to Eur. Phys. J. C (2016) 76:280 is provided. (orig.)

  10. Outside finance, dominant investors and strategic transparency

    NARCIS (Netherlands)

    Perotti, E.C.; von Thadden, E.-L.

    2000-01-01

    This paper studies optimal financial contracts and product market competition under a strategic transparency decision. When firms seeking outside finance resort to actively monitored debt in order to commit against opportunistic behaviour, the dominant lender can influence corporate transparency.

  11. Genetics Home Reference: autosomal dominant hypocalcemia

    Science.gov (United States)

    ... low levels of a hormone called parathyroid hormone (hypoparathyroidism). This hormone is involved in the regulation of ... Other Names for This Condition ADH autosomal dominant hypoparathyroidism familial hypercalciuric hypocalcemia familial hypocalcemia Related Information How ...

  12. A Boundary Property for Upper Domination

    KAUST Repository

    AbouEisha, Hassan M.

    2016-08-08

    An upper dominating set in a graph is a minimal (with respect to set inclusion) dominating set of maximum cardinality.The problem of finding an upper dominating set is generally NP-hard, but can be solved in polynomial time in some restricted graph classes, such as P4-free graphs or 2K2-free graphs.For classes defined by finitely many forbidden induced subgraphs, the boundary separating difficult instances of the problem from polynomially solvable ones consists of the so called boundary classes.However, none of such classes has been identified so far for the upper dominating set problem.In the present paper, we discover the first boundary class for this problem.

  13. Epigenetics of dominance for enzyme activity

    Indian Academy of Sciences (India)

    Unknown

    Acid phosphatase; dominance; Drosophila malerkotliana; epigenetics; heterodimeric allozymes; subunit interaction. J. Biosci. | Vol. 27 | No. ... Department of Genetics, Punjab Agricultural University, Ludhiana 141 004, India. *Corresponding ...... the genetic and complementation maps of the locus specifying the enzyme; J.

  14. Autosomal Dominant Polycystic Kidney Disease, incidental finding ...

    African Journals Online (AJOL)

    N.J. Gildenhuys

    2016-06-30

    Jun 30, 2016 ... Abbreviations: ADPKD, Autosomal Dominant Polycystic Kidney Disease; UPJ, congenital ureteropelvic junction obstruction; HK, horseshoe kidney;. RCC, renal cell carcinoma; MVA, motor vehicle accident; PVA, pedestrian vehicle accident; GH, gross haematuria; AP, abdominal pain; FP, flank pain;.

  15. Finding Dominators via Disjoint Set Union

    OpenAIRE

    Fraczak, Wojciech; Georgiadis, Loukas; Miller, Andrew; Tarjan, Robert E.

    2013-01-01

    The problem of finding dominators in a directed graph has many important applications, notably in global optimization of computer code. Although linear and near-linear-time algorithms exist, they use sophisticated data structures. We develop an algorithm for finding dominators that uses only a "static tree" disjoint set data structure in addition to simple lists and maps. The algorithm runs in near-linear or linear time, depending on the implementation of the disjoint set data structure. We g...

  16. 2-domination number of generalized Petersen graphs

    Indian Academy of Sciences (India)

    35

    2Department of Computer Science, Yazd University, Yazd, Iran. Abstract. Let G = (V,E) be a graph. A subset S ⊆ V is a k-dominating set of. G if each vertex ... on the area of domination in graphs and its applications we refer the reader to [6, 7]. The generalized Petersen graph P(n, k)=(V,E) is defined as follows: V = {v1,v2,...

  17. Dominant white spotting in the Chinese hamster.

    Science.gov (United States)

    Henwood, C; Henwood, J; Robinson, R

    1987-01-01

    An autosomal dominant white spotting mutant is described for the Chinese hamster. The mutant gene is designated as dominant spot (symbol Ds). The homozygote DsDs is a prenatal lethal while the heterozygote Ds + displays white spotting. The expression of white is variable, ranging from a white forehead spot to extensive white on the body. The venter is invariably white. Growth appears to be normal and the fertility of both sizes shows no impairment.

  18. Detecting seasonal and cyclical trends in agricultural runoff water quality-hypothesis tests and block bootstrap power analysis.

    Science.gov (United States)

    Uddameri, Venkatesh; Singaraju, Sreeram; Hernandez, E Annette

    2018-02-21

    Seasonal and cyclic trends in nutrient concentrations at four agricultural drainage ditches were assessed using a dataset generated from a multivariate, multiscale, multiyear water quality monitoring effort in the agriculturally dominant Lower Rio Grande Valley (LRGV) River Watershed in South Texas. An innovative bootstrap sampling-based power analysis procedure was developed to evaluate the ability of Mann-Whitney and Noether tests to discern trends and to guide future monitoring efforts. The Mann-Whitney U test was able to detect significant changes between summer and winter nutrient concentrations at sites with lower depths and unimpeded flows. Pollutant dilution, non-agricultural loadings, and in-channel flow structures (weirs) masked the effects of seasonality. The detection of cyclical trends using the Noether test was highest in the presence of vegetation mainly for total phosphorus and oxidized nitrogen (nitrite + nitrate) compared to dissolved phosphorus and reduced nitrogen (total Kjeldahl nitrogen-TKN). Prospective power analysis indicated that while increased monitoring can lead to higher statistical power, the effect size (i.e., the total number of trend sequences within a time-series) had a greater influence on the Noether test. Both Mann-Whitney and Noether tests provide complementary information on seasonal and cyclic behavior of pollutant concentrations and are affected by different processes. The results from these statistical tests when evaluated in the context of flow, vegetation, and in-channel hydraulic alterations can help guide future data collection and monitoring efforts. The study highlights the need for long-term monitoring of agricultural drainage ditches to properly discern seasonal and cyclical trends.

  19. SOME CONSIDERATIONS ON ABUSE OF DOMINANT POSITION

    Directory of Open Access Journals (Sweden)

    Ovidiu Maican

    2007-12-01

    Full Text Available Article 82 (formerly 86 EC contains four essential elements (an undertaking, a dominant position, an abuse of that position and the abuse must affect trade between member states. The term undertakings is subject to the same broad interpretation as that applied to article 81 (formerly 85 EC and covers the same activities, both public and private.The Community interest must be also taken into account. Although it is not clear precisely what this element of article 86 requires, it will clearly curtail the scope of the exception provided under this article. Although abusive behavior of undertakings in a dominant position is prohibited, it must be recalled that merely being in a strong position is not a problem in itself. It is necessary for major players in a market to be aware of their position because practices which would not fall foul of article 82 (formerly 86 EC, where an undertaking is not dominant, will do so where dominance is established. A refusal to deal by a non-dominant undertaking would not be an abuse within article 82 (formerly 86 EC, but it will be so where the undertaking is dominant.

  20. Finite element analysis of the cyclic indentation of bilayer enamel

    Science.gov (United States)

    Jia, Yunfei; Xuan, Fu-zhen; Chen, Xiaoping; Yang, Fuqian

    2014-04-01

    Tooth enamel is often subjected to repeated contact and often experiences contact deformation in daily life. The mechanical strength of the enamel determines the biofunctionality of the tooth. Considering the variation of the rod arrangement in outer and inner enamel, we approximate enamel as a bilayer structure and perform finite element analysis of the cyclic indentation of the bilayer structure, to mimic the repeated contact of enamel during mastication. The dynamic deformation behaviour of both the inner enamel and the bilayer enamel is examined. The material parameters of the inner and outer enamel used in the analysis are obtained by fitting the finite element results with the experimental nanoindentation results. The penetration depth per cycle at the quasi-steady state is used to describe the depth propagation speed, which exhibits a two-stage power-law dependence on the maximum indentation load and the amplitude of the cyclic load, respectively. The continuous penetration of the indenter reflects the propagation of the plastic zone during cyclic indentation, which is related to the energy dissipation. The outer enamel serves as a protective layer due to its great resistance to contact deformation in comparison to the inner enamel. The larger equivalent plastic strain and lower stresses in the inner enamel during cyclic indentation, as calculated from the finite element analysis, indicate better crack/fracture resistance of the inner enamel.

  1. Selective discrimination of cyclodextrin diols using cyclic sulfates

    DEFF Research Database (Denmark)

    Petrillo, Marta; Marinescu, Lavinia; Rousseau, Cyril

    2009-01-01

    A method for selective monofunctionalition of readily available cyclodextrin diols (2(A-F),3(A-F),6(B,C,E,F)-hexadeca-O-benzyl-alpha-cyclodextrin and 2(A-G),3(A-G),6(B,C,E-G)-nonadeca-O-benzyl-beta-cyclodextrin) by regioselective nucleophilic opening of their cyclic sulfates is presented. Althoug...

  2. Topology and symmetry of surface Majorana arcs in cyclic superconductors

    Science.gov (United States)

    Mizushima, Takeshi; Nitta, Muneto

    2018-01-01

    We study the topology and symmetry of surface Majorana arcs in superconductors with nonunitary "cyclic" pairing. Cyclic p -wave pairing may be realized in a cubic or tetrahedral crystal, while it is a candidate for the interior P32 superfluids of neutron stars. The cyclic state is an admixture of full gap and nodal gap with eight Weyl points and the low-energy physics is governed by itinerant Majorana fermions. We here show the evolution of surface states from Majorana cone to Majorana arcs under rotation of surface orientation. The Majorana cone is protected solely by an accidental spin rotation symmetry and fragile against spin-orbit coupling, while the arcs are attributed to two topological invariants: the first Chern number and one-dimensional winding number. Lastly, we discuss how topologically protected surface states inherent to the nonunitary cyclic pairing can be captured from surface probes in candidate compounds, such as U1 -xThxBe13 . We examine tunneling conductance spectra for two competitive scenarios in U1 -xThxBe13 —the degenerate Eu scenario and the accidental scenario.

  3. Mechanical properties of concrete to cyclic uniaxial tensile loading ...

    Indian Academy of Sciences (India)

    The mechanical properties of concrete under cyclic tensile loading using square waveform, sine waveform and ramp waveform are studied. ... College of Civil and Transportation Engineering, Hobai University, Nanjing 210098, China; College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing ...

  4. Characterizing and modelling cyclic behaviour in non-stationary ...

    Indian Academy of Sciences (India)

    to comprise of stochastic fluctuations as well as cyclic variations at different scales. The wavelet transform ... analysis shows that at small time scales, the fluctuations are primarily stochastic in nature; at higher scales the ..... here also to overcome the problem of GP optimization procedure settling down to persistent solutions ...

  5. 21 CFR 862.1230 - Cyclic AMP test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cyclic AMP test system. 862.1230 Section 862.1230 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862...

  6. Optimum Design and Operation of Cyclic Storage Systems; Lumped Approach

    Directory of Open Access Journals (Sweden)

    Leila Ostadrahimi

    2007-01-01

    Full Text Available Conjunctive use of surface and groundwater resources is a preferred approach in water resources management. Compared to dam construction, groundwater has certain advantages, among which are less costs, less sedimentation and evaporation, fewer water quality problems, and less social and cultural problems. To reduce the major problems associated with the development of large-scale surface impoundment systems, cyclic storage systems can be used as an alternative. A cyclic storage system (CYCS is an integrated interactive system consisting of two subsystems of surface water storage (reservoir and groundwater; this system together with artificial recharge is able to satisfy the predefined demands with rather high reliability. In order to optimize these systems, one must consider the hydraulic interactions between all the components, but unfortunately it has been neglected in many studies. In this article, a nonlinear optimization model for design and operation of cyclic storage systems has been developed using the lumped approach. In order to evaluate the model, its results have been compared with the results of a model in which distributed approach had been deployed, and so the efficiency of lumped models to solve the problems of cyclic storage systems has been investigated.

  7. Towards Green Cyclic Carbonate Synthesis : Heterogeneous and Homogeneous Catalyst Development

    NARCIS (Netherlands)

    Stewart, J.A.

    2015-01-01

    This PhD research serves to implement both known and novel catalytic systems for the purpose of cyclic carbonate synthesis from biomass-derived substrates. Such products have been earmarked as potential monomers for non-isocyanate polyurethanes (NIPUs), amongst other uses. Particular attention has

  8. METHODOLOGICAL ASPECTS OF ECONOMIC EVENTS CYCLICITY METHOD CONSIDERATION

    Directory of Open Access Journals (Sweden)

    Yaskova Natalia Yur'ievna

    2017-07-01

    Full Text Available The cyclicity of economic phenomena is not only their immanent property but also the subject of economic analysis. The modern way of making managerial decisions requires analysis of a number of cycles that fill any kind of activity. Accounting and reconciliation of construction, design, investment, purchasing, reproduction, leasing and other cycles is important for the investment and construction sector, both from the point of view of the need for their synchronization and from the position of determining trends in sectoral development. The analysis has showed that three main types of development are characteristic for investment and construction activity. Increasing intensity is inherent in a high level of cyclic synchronization. The degradation trend arises as a result of mismatched cycles. The stabilization character is inherent in the regular modes of maintaining the established proportions and cyclical inter-conformity. The study of the cyclical nature of investment and building processes is impossible without understanding their co-ordination. The principles of synchronization and subordination of the cycles should be used not only for the construction of cost-effective systems but also for the development of management tools.

  9. Laboratory experiments of bucket foundations under cyclic loading

    DEFF Research Database (Denmark)

    Foglia, Aligi; Ibsen, Lars Bo

    This report collects information on the experimental campaign concerning bucket foundations under lateral cyclic loading conducted by the authors between 2011 and 2014. The report includes a step by step manual on the test procedures and a number of information and graphs for each experiment...

  10. The comparison of cyclic deformation curve determination for ADI

    Czech Academy of Sciences Publication Activity Database

    Zapletal, J.; Obrtlík, Karel; Věchet, S.

    308 2005, - (2005), s. 305-309 ISSN 1429-6055. [Miedzynarodowe sympozjum /20./. Ustroň-Jaszowiec, 07.12.2005-09.12.2005] R&D Projects: GA ČR(CZ) GA106/03/1265 Institutional research plan: CEZ:AV0Z20410507 Keywords : cyclic stress-strain curve * austempered ductile iron Subject RIV: JG - Metallurgy

  11. Expression and diagnostic utility of anti-cyclic citrullinated peptide ...

    African Journals Online (AJOL)

    Background: Juvenile idiopathic arthritis (JIA) is a clinically heterogeneous group of arthritis occurring in children. Anti-cyclic citrullinated peptide (anti-CCP) antibodies have been recently included in the revised diagnostic criteria for adult onset rheumatoid arthritis. Its diagnostic value in JIA is still debatable. Objective: The ...

  12. Antifungal cyclic peptides from the marine sponge Microscleroderma herdmani

    Science.gov (United States)

    Screening natural product extracts from National Cancer Institute Open Repository for antifungal discovery afforded hits for bioassay-guided fractionation. Upon LC-MS analysis of column fractions with antifungal activities to generate information on chemical structure, two new cyclic hexapeptides, m...

  13. Aeroelastic Vibrations and Stability in Cyclic Symmetric Domains

    Directory of Open Access Journals (Sweden)

    Bernard Lalanne

    2000-01-01

    wing. In this way, aerodynamic forces may be obtained as general as required, depending on successive time derivatives of degrees of freedom in addition to themselves. Finally, some special cases are given and stability is studied for a cyclic periodic blade assembly, even when mistuning between sectors can occur.

  14. Cyclic machine scheduling with tool transportation - additional calculations

    NARCIS (Netherlands)

    Kuijpers, C.M.H.

    2001-01-01

    In the PhD Thesis of Kuijpers a cyclic machine scheduling problem with tool transportation is considered. For the problem with two machines, it is shown that there always exists an optimal schedule with a certain structure. This is done by means of an elaborate case study. For a number of cases some

  15. Skill Retention and Relearning--A Proposed Cyclical Model.

    Science.gov (United States)

    Ginzburg, S.; Dar-El, E. M.

    2000-01-01

    The relationship between relearning and retention was examined during refresher training for 53 Israeli soldiers operating an electronic system. The longer the training interval, the lower the operator's performance level. Partial simulation was suitable for retraining in complex tasks. A cyclical behavior model of learning, forgetting, and…

  16. Cyclic irradiation method for production of radioisotope tracers using ...

    African Journals Online (AJOL)

    Cyclic Irradiation Method (CIM) involving repeated irradiation of samples at regular time intervals to build up activity has been adopted for the production of 82 Br, 72 Ga, 140La, 24 Na and 46 Sc isotopes using the low power Ghana Research Reactor-1. The results indicate that the specific activities of radioisotopes from ...

  17. Retinal Cyclic Nucleotide-Gated Channels: From Pathophysiology to Therapy

    Directory of Open Access Journals (Sweden)

    Stylianos Michalakis

    2018-03-01

    Full Text Available The first step in vision is the absorption of photons by the photopigments in cone and rod photoreceptors. After initial amplification within the phototransduction cascade the signal is translated into an electrical signal by the action of cyclic nucleotide-gated (CNG channels. CNG channels are ligand-gated ion channels that are activated by the binding of cyclic guanosine monophosphate (cGMP or cyclic adenosine monophosphate (cAMP. Retinal CNG channels transduce changes in intracellular concentrations of cGMP into changes of the membrane potential and the Ca2+ concentration. Structurally, the CNG channels belong to the superfamily of pore-loop cation channels and share a common gross structure with hyperpolarization-activated cyclic nucleotide-gated (HCN channels and voltage-gated potassium channels (KCN. In this review, we provide an overview on the molecular properties of CNG channels and describe their physiological role in the phototransduction pathways. We also discuss insights into the pathophysiological role of CNG channel proteins that have emerged from the analysis of CNG channel-deficient animal models and human CNG channelopathies. Finally, we summarize recent gene therapy activities and provide an outlook for future clinical application.

  18. Cyclic antibiotic therapy for diverticular disease: a critical reappraisal.

    Science.gov (United States)

    Zullo, Angelo; Hassan, Cesare; Maconi, Giovanni; Manes, Gianpiero; Tammaro, Gianfranco; De Francesco, Vincenzo; Annibale, Bruno; Ficano, Leonardo; Buri, Luigi; Gatto, Giovanni; Lorenzetti, Roberto; Campo, Salvatore M; Ierardi, Enzo; Pace, Fabio; Morini, Sergio

    2010-09-01

    Different symptoms have been attributed to uncomplicated diverticular disease (DD). Poor absorbable antibiotics are largely used for uncomplicated DD, mainly for symptom treatment and prevention of diverticulitis onset. Controlled trials on cyclic administration of rifaximin in DD patients were evaluated. Four controlled, including 1 double-blind and 3 open-label, randomized studies were available. Following a long-term cyclic therapy, a significant difference emerged in the global symptoms score (range: 0-18) between rifaximin plus fibers (from 6-6.5 to 1-2) and fibers alone (from 6.7 to 2-3.8), although the actual clinically relevance of such a very small difference remains to be ascertained. Moreover, a similar global symptom score reduction (from 6 to 2.4) can be achieved by simply recommending an inexpensive high-fiber diet. Current data suggest that cyclic rifaximin plus fibers significantly reduce the incidence of the first episode of acute diverticulitis as compared to fibers alone (1.03% vs 2.75%), but a cost-efficacy analysis is needed before this treatment can be routinely recommended. The available studies have been hampered by some limitations, and definite conclusions could not be drawn. The cost of a long-life, cyclic rifaximin therapy administered to all symptomatic DD patients would appear prohibitive.

  19. Cyclic flow shop scheduling problem with two-machine cells

    Directory of Open Access Journals (Sweden)

    Bożejko Wojciech

    2017-06-01

    Full Text Available In the paper a variant of cyclic production with setups and two-machine cell is considered. One of the stages of the problem solving consists of assigning each operation to the machine on which it will be carried out. The total number of such assignments is exponential. We propose a polynomial time algorithm finding the optimal operations to machines assignment.

  20. Mechanism of Cyclically Polarity Reversing Solar Magnetic Cycle as ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... We briefly describe historical development of the concept of solar dynamo mechanism that generates electric current and magnetic field by plasma ... The dynamo is the driver of the cyclically polarity reversing solar magnetic cycle. ... Department of Astronomy, University of Tokyo, Tokyo, Japan 113-0033.

  1. Cyclic deformation behaviour of austenitic steels at ambient and ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Abstract. The aim of the present investigation is to characterise cyclic deforma- tion behaviour and plasticity-induced martensite formation of metastable austenitic stainless steels at ambient and elevated temperatures, taking into account the influ- ence of the alloying elements titanium and niobium. Titanium and niobium are.

  2. Cyclic deformation behaviour of austenitic steels at ambient and ...

    Indian Academy of Sciences (India)

    Fatigue behaviour of X6CrNiTi1810 (AISI 321), X10CrNiCb189 (AISI 348) and X5CrNi1810 (AISI 304) is characterised by cyclic hardening and softening effects which are strongly influenced by specific loading conditions. Martensite formation varies with the composition, loading conditions, temperature and number of ...

  3. Evolutions of Yang Phase Under Cyclic Condition and Adiabatic Condition

    International Nuclear Information System (INIS)

    Qian Shangwu; Gu Zhiyu

    2005-01-01

    There are three non-integrable phases in literatures: Berry phase, Aharonov-Anandan phase, and Yang phase. This article discusses the evolutions of Yang phase under the cyclic condition and the adiabatic condition for the general time-dependent harmonic oscillator, thus reveals the intimate relations between these three non-integrable phases.

  4. Effect of Color Shading Procedures and Cyclic Loading on the ...

    African Journals Online (AJOL)

    2018-02-07

    Feb 7, 2018 ... How to cite this article: Tuncel I, Turp I, Usumez A. Effect of color shading procedures and cyclic loading on the biaxial flexural strength of zirconia. Niger J Clin Pract 2018;21:7-12. This is an open access article distributed under the terms of the Creative Commons. Attribution-NonCommercial-ShareAlike 3.0 ...

  5. Effect of Color Shading Procedures and Cyclic Loading on the ...

    African Journals Online (AJOL)

    Purpose: Zirconia is the most preferred ceramic restoration in posterior areas because of its flexural strength. The aim of the study is the evaluation of biaxial flexural strength of different colored zirconium oxide core materials after cyclic loading. Material and Methods: Zirconia discs (12 mm diameter and 1.2 mm thickness) ...

  6. A genus six cyclic tetragonal reduction of the Benney equations

    International Nuclear Information System (INIS)

    England, M; Gibbons, J

    2009-01-01

    A reduction of Benney's equations is constructed corresponding to Schwartz-Christoffel maps associated with a family of genus six cyclic tetragonal curves. The mapping function, a second kind Abelian integral on the associated Riemann surface, is constructed explicitly as a rational expression in derivatives of the Kleinian σ-function of the curve.

  7. Computational design of disulfide cyclic peptide as potential ...

    African Journals Online (AJOL)

    Development of genomic and proteomic studies coupled with computational sciences could facilitate the discovery of various target proteins and potential inhibitor to be developed as drugs. Several researches by molecular docking method have been conducted to design disulfide cyclic peptide ligand as potential inhibitors ...

  8. Random matrix theory for pseudo-Hermitian systems: Cyclic blocks

    Indian Academy of Sciences (India)

    We discuss the relevance of random matrix theory for pseudo-Hermitian systems, and, for Hamiltonians that break parity and time-reversal invariance . In an attempt to understand the random Ising model, we present the treatment of cyclic asymmetric matrices with blocks and show that the nearest-neighbour spacing ...

  9. Synergistic degradation of dentin by cyclic stress and buffer agitation.

    Science.gov (United States)

    Orrego, Santiago; Romberg, Elaine; Arola, Dwayne

    2015-04-01

    Secondary caries and non-carious lesions develop in regions of stress concentrations and oral fluid movement. The objective of this study was to evaluate the influence of cyclic stress and fluid movement on material loss and subsurface degradation of dentin within an acidic environment. Rectangular specimens of radicular dentin were prepared from caries-free unrestored 3rd molars. Two groups were subjected to cyclic cantilever loading within a lactic acid solution (pH = 5) to achieve compressive stresses on the inner (pulpal) or outer sides of the specimens. Two additional groups were evaluated in the same solution, one subjected to movement only (no stress) and the second held stagnant (control: no stress or movement). Exterior material loss profiles and subsurface degradation were quantified on the two sides of the specimens. Results showed that under cyclic stress material loss was significantly greater (p ≤ 0.0005) on the pulpal side than on the outer side and significantly greater (p ≤ 0.05) under compression than tension. However, movement only caused significantly greater material loss (p ≤ 0.0005) than cyclic stress. Subsurface degradation was greatest at the location of highest stress, but was not influenced by stress state or movement. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Undrained behaviour of volcanic soils under monotonic and cyclic loading

    Science.gov (United States)

    de Cristofaro, Martina; Brunzo, Antonia; Mottola, Luciano; Netti, Nadia; Olivares, Lucio; Orense, Rolando; Asadi, Sadeq

    2017-04-01

    Undrained behaviour of volcanic soils under monotonic and cyclic loading. In this study, we focus on the undrained behaviour of volcanic deposits under monotonic and cyclic loading in order to define the susceptibility to liquefaction of granular volcanic deposits. We assume that, in the case of saturated granular volcanic deposits susceptible to liquefaction, an undrained unstable behaviour can be responsible for both, the evolution of flowslide due to rainfall and liquefaction under seismic loading. Starting from these considerations we define a complex experimental program to analyze their undrained behaviour through laboratory testing on reconstituted specimens of cohesionless volcanic soils. The first part of the experimental program is devoted to the use of the steady state concept to evaluate the influence of void ratio and effective confining pressure on the undrained behaviour of Cervinara pyroclastic soils (Italy) under monotonic and cyclic loading. The second part of the experimental program is devoted to the analysis of the influence of particles crushing of pumice soils from Rangiriri (New Zeland) in both monotonic and cyclic undrained triaxial tests.

  11. Liquefaction and cyclic mobility model for saturated granular media

    Science.gov (United States)

    López-Querol, S.; Blázquez, R.

    2006-04-01

    A new constitutive law for the behaviour of undrained sand subjected to dynamic loading is presented. The proposed model works for small and large strain ranges and incorporates contractive and dilative properties of the sand into the unified numerical scheme. These features allow to correctly predict liquefaction and cyclic mobility phenomena for different initial relative densities of the soil. The model has been calibrated as an element test, by using cyclic simple shear data reported in the literature. For the contractive sand behaviour a well-known endochronic densification model has been used, whereas a plastic model with a new non-associative flow rule is applied when the sand tends to dilate. Both dilatancy and flow rule are based on a new state parameter, associated to the stiffness degradation of the material as the shaking goes on. Also, the function that represents the rearrangement memory of the soil takes a zero value when the material dilates, in order to easily model the change in the internal structure. Proceeding along this kind of approach, liquefaction and cyclic mobility are modelled with the same constitutive law, within the framework of a bi-dimensional FEM coupled algorithm developed in the paper. For calibration purposes, the behaviour of the soil in a cyclic simple shear test has been simulated, in order to estimate the influence of permeability, frequency of loading, and homogeneity of the shear stress field on the laboratory data.

  12. Fast Selective Detection of Pyocyanin Using Cyclic Voltammetry

    DEFF Research Database (Denmark)

    Al Atraktchi, Fatima Al-Zahraa; Breum Andersen, Sandra; Johansen, Helle Krogh

    2016-01-01

    method to detect pyocyanin in a complex electroactive environment using commercially available electrodes. It is shown that cyclic voltammetry measurements between –1.0 V to 1.0 V reveal a potential detection window of pyocyanin of 0.58–0.82 V that is unaffected by other redox-active interferents...

  13. Fast Selective Detection of Pyocyanin Using Cyclic Voltammetry

    DEFF Research Database (Denmark)

    Alatraktchi, Fatima AlZahra'a; Andersen, Sandra Breum; Johansen, Helle Krogh

    2016-01-01

    method to detect pyocyanin in a complex electroactive environment using commercially available electrodes. It is shown that cyclic voltammetry measurements between -1.0 V to 1.0 V reveal a potential detection window of pyocyanin of 0.58-0.82 V that is unaffected by other redox-active interferents...

  14. Biosynthesis and regulation of cyclic lipopeptides in Pseudomonas fluorescens

    NARCIS (Netherlands)

    Bruijn, de I.

    2009-01-01

    Cyclic lipopeptides (CLPs) are surfactant and antibiotic metabolites produced by a variety of bacterial
    genera. For the genus Pseudomonas, many structurally different CLPs have been identified. CLPs play an
    important role in surface motility of Pseudomonas strains, but also in virulence

  15. Optimal control of FES-induced cyclical leg movements

    NARCIS (Netherlands)

    Veltink, Petrus H.; Franken, H.M.; Franken, Henry M.; d' Hollosy, Wendy; Burger, G.J.; Burger, Gert-Jan; Boom, H.B.K.

    1991-01-01

    An optimal control strategy for FES-induced cyclical movements is proposed. Optimal stimulation patterns are determined on the basis of a criterium, consisting of desired movement parameters and a dynamic model of the system. Preliminary results of the identification and optimization are shown.

  16. Cyclic Nucleotide Monophosphates and Their Cyclases in Plant Signaling

    KAUST Repository

    Gehring, Christoph A.

    2017-10-04

    The cyclic nucleotide monophosphates (cNMPs), and notably 3′,5′-cyclic guanosine monophosphate (cGMP) and 3′,5′-cyclic adenosine monophosphate (cAMP) are now accepted as key signaling molecules in many processes in plants including growth and differentiation, photosynthesis, and biotic and abiotic defense. At the single molecule level, we are now beginning to understand how cNMPs modify specific target molecules such as cyclic nucleotide-gated channels, while at the systems level, a recent study of the Arabidopsis cNMP interactome has identified novel target molecules with specific cNMP-binding domains. A major advance came with the discovery and characterization of a steadily increasing number of guanylate cyclases (GCs) and adenylate cyclases (ACs). Several of the GCs are receptor kinases and include the brassinosteroid receptor, the phytosulfokine receptor, the Pep receptor, the plant natriuretic peptide receptor as well as a nitric oxide sensor. We foresee that in the near future many more molecular mechanisms and biological roles of GCs and ACs and their catalytic products will be discovered and further establish cNMPs as a key component of plant responses to the environment.

  17. Optical fibre Bragg grating recorded in TOPAS cyclic olefin copolymer

    DEFF Research Database (Denmark)

    Johnson, I.P.; Yuan, Scott Wu; Stefani, Alessio

    2011-01-01

    A report is presented on the inscription of a fibre Bragg grating into a microstructured polymer optical fibre fabricated from TOPAS cyclic olefin copolymer. This material offers two important advantages over poly (methyl methacrylate), which up to now has formed the basis for polymer fibre Bragg...

  18. Cyclic Voltammetry of Biopolymer Heparin at PVC Plasticized Liquid Membrane

    Czech Academy of Sciences Publication Activity Database

    Samec, Zdeněk; Trojánek, Antonín; Langmaier, Jan; Samcová, E.

    2003-01-01

    Roč. 5, - (2003), s. 867-870 ISSN 1388-2481 R&D Projects: GA ČR GA203/04/0424 Institutional research plan: CEZ:AV0Z4040901 Keywords : cyclic voltammetry * PVC plasticized liquit membrane * heparin Subject RIV: CG - Electrochemistry Impact factor: 2.300, year: 2003

  19. A novel hydrogen-bonded cyclic dibromide in an organic ...

    Indian Academy of Sciences (India)

    Unknown

    A novel hydrogen-bonded cyclic dibromide in an organic diammonium salt. #. BIKSHANDARKOIL R SRINIVASAN,1,* ... rangement of anions and cations may be viewed as a typical lamellar structure. The crystal water mole- cules can be ..... layers of organic (dbtmen)2+ cations (dashed lines indi- cate hydrogen bonding).

  20. A theoretical model for predicting neutron fluxes for cyclic Neutron ...

    African Journals Online (AJOL)

    A theoretical model has been developed for prediction of thermal neutron fluxes required for cyclic irradiations of a sample to obtain the same activity previously used for the detection of any radionuclide of interest. The model is suitable for radiotracer production or for long-lived neutron activation products where the ...

  1. Drained Response of Bucket Foundations under Cyclic Lateral Load

    DEFF Research Database (Denmark)

    Foglia, Aligi; Ibsen, Lars Bo

    2013-01-01

    Introduction The monopod bucket foundation is an innovative support structure for offshore wind turbines. It consists of a shallow embedded foundation which penetrates the seabed by means of a suction created within the caisson. The behaviour of bucket foundations against long-term lateral cyclic...

  2. Cyclic AMP response element binding protein and brain-derived ...

    Indian Academy of Sciences (India)

    Madhu

    the role of CREB and BDNF in depression and as targets/mediators of antidepressant action. [Nair A and Vaidya V A 2006 Cyclic AMP response element binding protein and brain-derived neurotrophic factor: Molecules that modulate our mood?; J. Biosci. 31 423–434]. Keywords. Antidepressant; depression; hippocampus ...

  3. Resistance to cyclic loading of teeth restored with posts

    DEFF Research Database (Denmark)

    Sahafi, A; Peutzfeldt, A; Ravnholt, G

    2005-01-01

    This in vitro study evaluated the effect of presence of post, presence of core, and of shape, type, and surface treatment of posts on resistance to cyclic loading of crowned human teeth. For all teeth, crowns designed without ferrule were cast in sterling silver and luted with resin cement (Panavia...

  4. Long-term Cyclic Variations of Prominences, Green and Red ...

    Indian Academy of Sciences (India)

    Abstract. Long-term cyclic variations in the distribution of promi- nences and intensities of green (530.3 nm) and red (637.4 nm) coronal emission lines over solar cycles 18-23 are presented. Polar prominence branches will reach the poles at different epochs in cycle 23: the north branch at the beginning in 2002 and the ...

  5. Route and fleet design for cyclic inventory routing

    NARCIS (Netherlands)

    Raa, Birger; Dullaert, Wout

    2017-01-01

    This paper presents a novel solution approach for planning cyclic distribution from a single depot to multiple customers with constant, deterministic demand rates. The objective is to minimize the total cost rate consisting of fleet costs, distribution costs from the depot to the customers and

  6. Reaction of three cyclic thioester ligands with triiron dodecacarbonyl ...

    Indian Academy of Sciences (India)

    Zhiyin Xiao

    2017-09-27

    Sep 27, 2017 ... unknown iron carbonyl product was isolated in addition to complex 1. Although its precise structure was not established due to ... ysis were used to identify some of the isolated products. Possible reaction mechanisms of the cyclic ... duced in dropwise fashion. The color of the mixture turned slowly to yellow.

  7. Random matrix theory for pseudo-Hermitian systems: Cyclic blocks

    Indian Academy of Sciences (India)

    Abstract. We discuss the relevance of random matrix theory for pseudo-Hermitian sys- tems, and, for Hamiltonians that break parity P and time-reversal invariance T. In an attempt to understand the random Ising model, we present the treatment of cyclic asym- metric matrices with blocks and show that the nearest-neighbour ...

  8. Experimental and theoretical investigations into the stability of cyclic aminals

    Directory of Open Access Journals (Sweden)

    Edgar Sawatzky

    2016-10-01

    Full Text Available Background: Cyclic aminals are core features of natural products, drug molecules and important synthetic intermediates. Despite their relevance, systematic investigations into their stability towards hydrolysis depending on the pH value are lacking.Results: A set of cyclic aminals was synthesized and their stability quantified by kinetic measurements. Steric and electronic effects were investigated by choosing appropriate groups. Both molecular mechanics (MM and density functional theory (DFT based studies were applied to support and explain the results obtained. Rapid decomposition is observed in acidic aqueous media for all cyclic aminals which occurs as a reversible reaction. Electronic effects do not seem relevant with regard to stability, but the magnitude of the conformational energy of the ring system and pKa values of the N-3 nitrogen atom.Conclusion: Cyclic aminals are stable compounds when not exposed to acidic media and their stability is mainly dependent on the conformational energy of the ring system. Therefore, for the preparation and work-up of these valuable synthetic intermediates and natural products, appropriate conditions have to be chosen and for application as drug molecules their sensitivity towards hydrolysis has to be taken into account.

  9. Are international fund flows pro- or counter-cyclical?

    NARCIS (Netherlands)

    Li, Suxiao; de Haan, Jakob; Scholtens, Bert; Yang, Haizhen

    2015-01-01

    We investigate whether international fund flows are pro-or counter-cyclical by employing a concordance index. International fund flows are investments in bond and equity markets by institutional investors, such as mutual funds, exchange traded funds, closed-end funds and hedge funds. We find that

  10. Methods and systems for the formation of cyclic carbonates

    Science.gov (United States)

    Hatton, Trevor Alan; Jamison, Timothy F; Kozak, Jennifer Aiden; Simeon, Fritz; Wu, Jie

    2014-12-30

    Described herein are inventive methods for synthesis of cyclic carbonates from CO.sub.2 and epoxide. In some embodiments, the methods are carried out in the presence of a catalyst comprising an electrophilic halogen. In some embodiments, the methods are carried out in a flow reactor.

  11. Characterization of cyclical phases in the manufacturing industry in Spain

    Directory of Open Access Journals (Sweden)

    Mercè Sala

    2014-09-01

    Full Text Available 120 Purpose: The purpose of this paper is to characterize the cyclical phases of the manufacturing industry in Spain and detect which industries have more influence on the Spanish business cycle. We assume that economic growth is a priority; we are going to determine which industries have a more/less appropriate cyclical behavior according this priority. We analyze if the industries with better cyclical behavior are the ones that achieve greater co-movement with the business cycle of the Spanish economy, as this means they have a positive influence on economic activity. Design/methodology/approach: We examine the disaggregated quarterly IPI data of 16 manufacturing industries. Our methodology follows three steps. Firstly, we define cycle turning points; we follow the Harding and Pagan (2002 methodology. Secondly, we characterize the cyclical phases of the manufacturing industries in terms of duration, amplitude, deepness and steepness. We also determine the degree of inter-industrial cyclical synchronization and between industries in the cycle of the Spanish economy. This analysis is performed in two ways. On the one hand, we use the concordance index and the correlation coefficient. On the other hand, we work with indicators based on a consistency table. In the Third step, we apply a multi-objective methodology, specifically the compromise programming, to determine which industries have a more/less appropriate cyclical behavior according to the growth priority. Findings and Originality/value: The business cycle of the Spanish economy is positively influenced by high- and medium-tech industries, which have demonstrated their competitive capacity in international markets, and by medium- low-tech industries, with major strengths in R&D, and in survival and consolidation strategies. These results enable manufacturing industries to exert a positive effect on the business cycle that is weakened because many of them show a high correlation between

  12. A New Algorithm Using the Non-Dominated Tree to Improve Non-Dominated Sorting.

    Science.gov (United States)

    Gustavsson, Patrik; Syberfeldt, Anna

    2018-01-01

    Non-dominated sorting is a technique often used in evolutionary algorithms to determine the quality of solutions in a population. The most common algorithm is the Fast Non-dominated Sort (FNS). This algorithm, however, has the drawback that its performance deteriorates when the population size grows. The same drawback applies also to other non-dominating sorting algorithms such as the Efficient Non-dominated Sort with Binary Strategy (ENS-BS). An algorithm suggested to overcome this drawback is the Divide-and-Conquer Non-dominated Sort (DCNS) which works well on a limited number of objectives but deteriorates when the number of objectives grows. This article presents a new, more efficient algorithm called the Efficient Non-dominated Sort with Non-Dominated Tree (ENS-NDT). ENS-NDT is an extension of the ENS-BS algorithm and uses a novel Non-Dominated Tree (NDTree) to speed up the non-dominated sorting. ENS-NDT is able to handle large population sizes and a large number of objectives more efficiently than existing algorithms for non-dominated sorting. In the article, it is shown that with ENS-NDT the runtime of multi-objective optimization algorithms such as the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) can be substantially reduced.

  13. Cyclic delivery scheduling to customers with different priorities

    Directory of Open Access Journals (Sweden)

    Katarzyna Zofia Gdowska

    2013-12-01

    Full Text Available Background: In this paper a cyclic delivery scheduling problem for customers with different priorities is presented. Shops, which are provided with deliveries, are occasionally located in places which are crucial for the proper flow of traffic. In such places coordination of deliveries is crucial; therefore it allows to completely eliminate the phenomenon of the simultaneous arrivals of suppliers. Methods: In this paper the cyclic delivery scheduling problem for customers with different priorities was presented. To this theoretical problem a mix integer programming model was developed. Specific approach to the cyclic delivery scheduling problem is inspired by timetabling problem for urban public transport. Results: Mixed integer programming model was employed for solving four cases of cyclic delivery scheduling problem for customers with different priorities. When the value of the synchronization priority assigned to a single customer raised then the total number of synchronizations in the whole network decreased. In order to compare solutions a synchronization rate was utilized. A simple factor was utilized - the proportion of number of synchronizations of deliveries to a given customer to the total number of synchronizations obtained for the whole network. When the value of synchronization priority raised then the value of synchronization rate of this customer improved significantly. Conclusions: The mixed integer programming model for the cyclic delivery scheduling problem for customers with different priorities presented in this paper can be utilized for generating schedules of serving customers located in places where only one delivery can be received and unloaded at one go and where there is no space for other suppliers to wait in a queue. Such a schedule can be very useful for organizing deliveries to small shops united in a franchising network, since they operate in a way that is very similar to the network presented in this paper

  14. Testing and modeling of cyclically loaded rock anchors

    Directory of Open Access Journals (Sweden)

    Joar Tistel

    2017-12-01

    Full Text Available The Norwegian Public Roads Administration (NPRA is planning for an upgrade of the E39 highway route at the westcoast of Norway. Fixed links shall replace ferries at seven fjord crossings. Wide spans and large depths at the crossings combined with challenging subsea topography and environmental loads call for an extension of existing practice. A variety of bridge concepts are evaluated in the feasibility study. The structures will experience significant loads from deadweight, traffic and environment. Anchoring of these forces is thus one of the challenges met in the project. Large-size subsea rock anchors are considered a viable alternative. These can be used for anchoring of floating structures but also with the purpose of increasing capacity of fixed structures. This paper presents first a thorough study of factors affecting rock anchor bond capacity. Laboratory testing of rock anchors subjected to cyclic loading is thereafter presented. Finally, the paper presents a model predicting the capacity of a rock anchor segment, in terms of a ribbed bar, subjected to a cyclic load history. The research assumes a failure mode occurring in the interface between the rock anchor and the surrounding grout. The constitutive behavior of the bonding interface is investigated for anchors subjected to cyclic one-way tensile loads. The model utilizes the static bond capacity curve as a basis, defining the ultimate bond τbu and the slip s1 at τbu. A limited number of input parameters are required to apply the model. The model defines the bond-slip behavior with the belonging rock anchor capacity depending on the cyclic load level (τmax cy/τbu, the cyclic load ratio (R = τmin cy/τmax cy, and the number of load cycles (N. The constitutive model is intended to model short anchor lengths representing an incremental length of a complete rock anchor.

  15. Cyclic mechanical stretch reduces myofibroblast differentiation of primary lung fibroblasts.

    Science.gov (United States)

    Blaauboer, Marjolein E; Smit, Theo H; Hanemaaijer, Roeland; Stoop, Reinout; Everts, Vincent

    2011-01-07

    In lung fibrosis tissue architecture and function is severely hampered by myofibroblasts due to excessive deposition of extracellular matrix and tissue contraction. Myofibroblasts differentiate from fibroblasts under the influence of transforming growth factor (TGF) β(1) but this process is also controlled mechanically by cytoskeletal tension. In healthy lungs, the cytoskeleton of fibroblasts is mechanically strained during breathing. In stiffer fibrotic lung tissue, this mechanical stimulus is reduced, which may influence fibroblast-to-myofibroblast differentiation. Therefore, we investigated the effect of cyclic mechanical stretch on fibroblast-to-myofibroblast differentiation. Primary normal human lung fibroblasts were grown on BioFlex culture plates and stimulated to undergo myofibroblast differentiation by 10 ng/ml TGFβ(1). Cells were either or not subjected to cyclic mechanical stretch (sinusoidal pattern, maximum elongation 10%, 0.2 Hz) for a period of 48 h on a Flexercell apparatus. mRNA expression was analyzed by real-time PCR. Cyclic mechanical loading reduced the mRNA expression of the myofibroblast marker α-smooth muscle actin and the extracellular matrix proteins type-I, type-III, and type-V collagen, and tenascin C. These outcomes indicate that fibroblast-to-myofibroblast differentiation is reduced. Cyclic mechanical loading did not change the expression of the fibronectin ED-A splice variant, but did decrease the paracrine expression of TGFβ(1), thereby suggesting a possible regulation mechanism for the observed effects. The data suggest that cyclic loading experienced by healthy lung cells during breathing may prevent fibroblasts from differentiating towards myofibroblasts. Copyright © 2010 Elsevier Inc. All rights reserved.

  16. Mechanical Behavior of AZ31B Mg Alloy Sheets under Monotonic and Cyclic Loadings at Room and Moderately Elevated Temperatures

    Science.gov (United States)

    Nguyen, Ngoc-Trung; Seo, Oh Suk; Lee, Chung An; Lee, Myoung-Gyu; Kim, Ji-hoon; Kim, Heon Young

    2014-01-01

    Large-strain monotonic and cyclic loading tests of AZ31B magnesium alloy sheets were performed with a newly developed testing system, at different temperatures, ranging from room temperature to 250 °C. Behaviors showing significant twinning during initial in-plane compression and untwinning in subsequent tension at and slightly above room temperature were recorded. Strong yielding asymmetry and nonlinear hardening behavior were also revealed. Considerable Bauschinger effects, transient behavior, and variable permanent softening responses were observed near room temperature, but these were reduced and almost disappeared as the temperature increased. Different stress–strain responses were inherent to the activation of twinning at lower temperatures and non-basal slip systems at elevated temperatures. A critical temperature was identified to account for the transition between the twinning-dominant and slip-dominant deformation mechanisms. Accordingly, below the transition point, stress–strain curves of cyclic loading tests exhibited concave-up shapes for compression or compression following tension, and an unusual S-shape for tension following compression. This unusual shape disappeared when the temperature was above the transition point. Shrinkage of the elastic range and variation in Young’s modulus due to plastic strain deformation during stress reversals were also observed. The texture-induced anisotropy of both the elastic and plastic behaviors was characterized experimentally. PMID:28788514

  17. Mechanical Behavior of AZ31B Mg Alloy Sheets under Monotonic and Cyclic Loadings at Room and Moderately Elevated Temperatures

    Directory of Open Access Journals (Sweden)

    Ngoc-Trung Nguyen

    2014-02-01

    Full Text Available Large-strain monotonic and cyclic loading tests of AZ31B magnesium alloy sheets were performed with a newly developed testing system, at different temperatures, ranging from room temperature to 250 °C. Behaviors showing significant twinning during initial in-plane compression and untwinning in subsequent tension at and slightly above room temperature were recorded. Strong yielding asymmetry and nonlinear hardening behavior were also revealed. Considerable Bauschinger effects, transient behavior, and variable permanent softening responses were observed near room temperature, but these were reduced and almost disappeared as the temperature increased. Different stress–strain responses were inherent to the activation of twinning at lower temperatures and non-basal slip systems at elevated temperatures. A critical temperature was identified to account for the transition between the twinning-dominant and slip-dominant deformation mechanisms. Accordingly, below the transition point, stress–strain curves of cyclic loading tests exhibited concave-up shapes for compression or compression following tension, and an unusual S-shape for tension following compression. This unusual shape disappeared when the temperature was above the transition point. Shrinkage of the elastic range and variation in Young’s modulus due to plastic strain deformation during stress reversals were also observed. The texture-induced anisotropy of both the elastic and plastic behaviors was characterized experimentally.

  18. Adenosine 3':5'-cyclic monophosphate in higher plants: Isolation and characterization of adenosine 3':5'-cyclic monophosphate from Kalanchoe and Agave.

    Science.gov (United States)

    Ashton, A R; Polya, G M

    1977-07-01

    1.3':5'-Cyclic AMP was extensively purified from Kalanchoe daigremontiana and Agave americana by neutral alumina and anion- and cation-exchange column chromatography. Inclusion of 3':5'-cyclic [8-3H]AMP from the point of tissue extraction permitted calculation of yields. The purification procedure removed contaminating material that was shown to interfere with the 3':5'-cyclic AMP estimation and characterization procedures. 2. The partially purified 3':5'-cyclic AMP was quantified by means of a radiochemical saturation assay using an ox heart 3':5'-cyclic AMP-binding protein and by an assay involving activation of a mammalian protein kinase. 3. The plant 3':5'-cyclic AMP co-migrated with 3':5'-cyclic [8-3H]AMP on cellulose chromatography, poly(ethyleneimine)-cellulose chromatography and silica-gel t.l.c. developed with several solvent systems. 4. The plant 3':5'-cyclic AMP was degraded by ox heart 3':5'-cyclic nucleotide phosphodiesterase at the same rates as authentic 3':5'-cyclic AMP. 1-Methyl-3-isobutylxanthine (1 mM), a specific inhibitor of the 3':5'-cyclic nucleotide phosphodieterase, completely inhibited such degradation. 5. The concentrations of 3':5'-cyclic AMP satisfying the above criteria in Kalanchoe and Agave were 2-6 and 1 pmol/g fresh wt. respectively. Possible bacterial contribution to these analyses was estimated to be less than 0.002pmol/g fresh wt. Evidence for the occurrence of 3':5'-cyclic AMP in plants is discussed.

  19. Adenosine 3':5'-cyclic monophosphate in higher plants: Isolation and characterization of adenosine 3':5'-cyclic monophosphate from Kalanchoe and Agave.

    Science.gov (United States)

    Ashton, A R; Polya, G M

    1977-01-01

    1.3':5'-Cyclic AMP was extensively purified from Kalanchoe daigremontiana and Agave americana by neutral alumina and anion- and cation-exchange column chromatography. Inclusion of 3':5'-cyclic [8-3H]AMP from the point of tissue extraction permitted calculation of yields. The purification procedure removed contaminating material that was shown to interfere with the 3':5'-cyclic AMP estimation and characterization procedures. 2. The partially purified 3':5'-cyclic AMP was quantified by means of a radiochemical saturation assay using an ox heart 3':5'-cyclic AMP-binding protein and by an assay involving activation of a mammalian protein kinase. 3. The plant 3':5'-cyclic AMP co-migrated with 3':5'-cyclic [8-3H]AMP on cellulose chromatography, poly(ethyleneimine)-cellulose chromatography and silica-gel t.l.c. developed with several solvent systems. 4. The plant 3':5'-cyclic AMP was degraded by ox heart 3':5'-cyclic nucleotide phosphodiesterase at the same rates as authentic 3':5'-cyclic AMP. 1-Methyl-3-isobutylxanthine (1 mM), a specific inhibitor of the 3':5'-cyclic nucleotide phosphodieterase, completely inhibited such degradation. 5. The concentrations of 3':5'-cyclic AMP satisfying the above criteria in Kalanchoe and Agave were 2-6 and 1 pmol/g fresh wt. respectively. Possible bacterial contribution to these analyses was estimated to be less than 0.002pmol/g fresh wt. Evidence for the occurrence of 3':5'-cyclic AMP in plants is discussed. PMID:196595

  20. STRUCTURE FORMATION OF HYPOEUTECTOID CONSTRUCTIONS STEELS AT CARBONITRIDING WITH LOCAL INDUCTION CYCLIC HEATING

    Directory of Open Access Journals (Sweden)

    G. A. Tkachenko

    2010-01-01

    Full Text Available Improvement of mechanical characteristics of details of the soil-cultivating car. Structurization at cyclic heating of steels. The reasons of an intensification of diffusion at cyclic heating. Structure crushing, impact strength and hardness increase.