WorldWideScience

Sample records for hf pathophysiology importantly

  1. Arylsulfatase A: An Important Metabolic Factor in Pathophysiology of Different Diseases

    Directory of Open Access Journals (Sweden)

    Zsolt Kovacs

    2015-09-01

    Full Text Available Arylsulfatase A (ARSA is a lysosomal enzyme that plays an important role in catalysis of degradation of cerebrosidesulphate. The deficiency of this lysosomal enzyme causes an autosomal recessive disorder, called metachromatic leucodystrophy. However, a low ARSA activity can be observed in clinically healthy people, called ARSA pseudodeficiency. In our study we investigated the possible linkage between ARSA activity and sulfatide deficiency causing characteristic aspects of degenerative diseases, such as end stage kidney disease, type 2 Diabetes mellitus, Parkinson syndrome, prostate cancer and HIV (Human Immunodeficiency Virus infection. We used a spectrophotometric method to determine the activity of ARSA. This method of enzyme dosage is based on a 4 hour long hydrolysis of the ARSA enzyme on 4-nitrocatechol sulfate (p-NCS substrate. The unit of this measurement is nmol/ml/4h. Our findings show significant values in type 2 diabetes, Parkinson syndrome and chronic kidney disease. The importance of sulfatide in these diseases is well-known, thus presumably the variation of the ARSA’s activity might play an important role in the pathophysiology of these diseases, involving a vicious cycle between sulfatide degradation andthese diseases.

  2. Importance of endogenous kynurenic acid in brainm catecholaminergic processes and in the pathophysiology of schizophrenia

    OpenAIRE

    Erhardt, Sophie

    2001-01-01

    Kynurenic acid is a metabolite of tryptophan and the only known naturally occurring NMethylD-Aspartic acid (NMDA)-receptor antagonist (at the co-agonist glycine site) in the human brain. The aim of the present work was to investigate the physiological and pharmacological significance of endogenous kvnurenic acid as well as its putative pathophysiological implications. For this purpose in vivo extracellular single unit recording from rat brain catecholamine neurons were u...

  3. Multidrug resistance proteins (MRPs, ABCCs): importance for pathophysiology and drug therapy.

    Science.gov (United States)

    Keppler, Dietrich

    2011-01-01

    The nine multidrug resistance proteins (MRPs) represent the major part of the 12 members of the MRP/CFTR subfamily belonging to the 48 human ATP-binding cassette (ABC) transporters. Cloning, functional characterization, and cellular localization of most MRP subfamily members have identified them as ATP-dependent efflux pumps with a broad substrate specificity for the transport of endogenous and xenobiotic anionic substances localized in cellular plasma membranes. Prototypic substrates include glutathione conjugates such as leukotriene C(4) for MRP1, MRP2, and MRP4, bilirubin glucuronosides for MRP2 and MRP3, and cyclic AMP and cyclic GMP for MRP4, MRP5, and MRP8. Reduced glutathione (GSH), present in living cells at millimolar concentrations, modifies the substrate specificities of several MRPs, as exemplified by the cotransport of vincristine with GSH by MRP1, or by the cotransport of GSH with bile acids or of GSH with leukotriene B(4) by MRP4.The role of MRP subfamily members in pathophysiology may be illustrated by the MRP-mediated release of proinflammatory and immunomodulatory mediators such as leukotrienes and prostanoids. Pathophysiological consequences of many genetic variants leading to a lack of functional MRP protein in the plasma membrane are observed in the hereditary MRP2 deficiency associated with conjugated hyperbilirubinemia in Dubin-Johnson syndrome, in pseudoxanthoma elasticum due to mutations in the MRP6 (ABCC6) gene, or in the type of human earwax and osmidrosis determined by single nucleotide polymorphisms in the MRP8 (ABCC8) gene. The hepatobiliary and renal elimination of many drugs and their metabolites is mediated by MRP2 in the hepatocyte canalicular membrane and by MRP4 as well as MRP2 in the luminal membrane of kidney proximal tubules. Therefore, inhibition of these efflux pumps affects pharmacokinetics, unless compensated by other ATP-dependent efflux pumps with overlapping substrate specificities.

  4. Pathophysiology of acute heart failure: a world to know.

    Science.gov (United States)

    Sánchez-Marteles, M; Rubio Gracia, J; Giménez López, I

    2016-01-01

    Our understanding of the pathophysiological mechanisms of heart failure (HF) has changed considerably in recent years, progressing from a merely haemodynamic viewpoint to a concept of systemic and multifactorial involvement in which numerous mechanisms interact and concatenate. The effects of these mechanisms go beyond the heart itself, to other organs of vital importance such as the kidneys, liver and lungs. Despite this, the pathophysiology of acute HF still has aspects that elude our deeper understanding. Haemodynamic overload, venous congestion, neurohormonal systems, natriuretic peptides, inflammation, oxidative stress and its repercussion on cardiac and vascular remodelling are currently considered the main players in acute HF. Starting with the concept of acute HF, this review provides updates on the various mechanisms involved in this disease. Copyright © 2015 Elsevier España, S.L.U. y Sociedad Española de Medicina Interna (SEMI). All rights reserved.

  5. Biological role of Interleukin 33 and its importance in pathophysiology of cardiovascular system

    Directory of Open Access Journals (Sweden)

    Agnieszka Czyżewska-Buczyńska

    2014-06-01

    Full Text Available Interleukin 33 (IL-33 is a member of the IL-1 cytokin family. It is expressed by various cells and tissues, mainly epithelial and endothelial cells. It is a cytokine with dual function. It may act both as a traditional cytokine and as intracellular nuclear factor, functioning as transcription regulator. Its biological effect via interaction with membrane-bound ST2 receptor and IL-1 receptor accessory protein (IL-1RAcP is associated with the induction of Th2-type immune response and IL-5 and IL-13 synthesis. IL-33 has a strong immunoregulatory properties. Depending on the type of activated cells, microenvironment, and costimulatory factors, IL-33 can act either as a pro- or anti-inflammatory cytokine. Recent studies indicate various protective effect of IL-33/ST2 sygnaling in atherosclerosis, obesity, disorders in glucose homeostasis and in heart diseases. The paper presents current state of knowledge about the structure and biological function of IL-33 and its receptor ST2, with particular emphasis on its role in pathophysiology of cardiovascular system.

  6. Role of anxiety in the pathophysiology of irritable bowel syndrome: importance of the amygdala

    National Research Council Canada - National Science Library

    Myers, Brent; Greenwood-Van Meerveld, Beverley

    2009-01-01

    .... The amygdala is an important structure for regulating anxiety with the central nucleus of the amygdala facilitating the activation of the hypothalamic-pituitary-adrenal axis and the autonomic nervous...

  7. Role of Anxiety in the Pathophysiology of Irritable Bowel Syndrome: Importance of the Amygdala

    OpenAIRE

    Brent Myers; Beverley Greenwood-VanMeerveld

    2009-01-01

    A common characteristic of irritable bowel syndrome (IBS) is that symptoms, including abdominal pain and abnormal bowel habits, are often triggered or exacerbated during periods of stress and anxiety. However, the impact of anxiety and affective disorders on the gastrointestinal (GI) tract is poorly understood and may in part explain the lack of effective therapeutic approaches to treat IBS. The amygdala is an important structure for regulating anxiety with the central nucleus of the amygdala...

  8. Role of anxiety in the pathophysiology of irritable bowel syndrome: importance of the amygdala.

    Science.gov (United States)

    Myers, Brent; Greenwood-Van Meerveld, Beverley

    2009-01-01

    A common characteristic of irritable bowel syndrome (IBS) is that symptoms, including abdominal pain and abnormal bowel habits, are often triggered or exacerbated during periods of stress and anxiety. However, the impact of anxiety and affective disorders on the gastrointestinal (GI) tract is poorly understood and may in part explain the lack of effective therapeutic approaches to treat IBS. The amygdala is an important structure for regulating anxiety with the central nucleus of the amygdala facilitating the activation of the hypothalamic-pituitary-adrenal axis and the autonomic nervous system in response to stress. Moreover, chronic stress enhances function of the amygdala and promotes neural plasticity throughout the amygdaloid complex. This review outlines the latest findings obtained from human studies and animal models related to the role of the emotional brain in the regulation of enteric function, specifically how increasing the gain of the amygdala to induce anxiety-like behavior using corticosterone or chronic stress increases responsiveness to both visceral and somatic stimuli in rodents. A focus of the review is the relative importance of mineralocorticoid receptor and glucocorticoid receptor-mediated mechanisms within the amygdala in the regulation of anxiety and nociceptive behaviors that are characteristic features of IBS. This review also discusses several outstanding questions important for future research on the role of the amygdala in the generation of abnormal GI function that may lead to potential targets for new therapies to treat functional bowel disorders such as IBS.

  9. Role of anxiety in the pathophysiology of irritable bowel syndrome: importance of the amygdala

    Directory of Open Access Journals (Sweden)

    Brent Myers

    2009-06-01

    Full Text Available A common characteristic of irritable bowel syndrome (IBS is that symptoms, including abdominal pain and abnormal bowel habits, are often triggered or exacerbated during periods of stress and anxiety. However, the impact of anxiety and affective disorders on the gastrointestinal (GI tract is poorly understood and may in part explain the lack of effective therapeutic approaches to treat IBS. The amygdala is an important structure for regulating anxiety with the central nucleus of the amygdala (CeA facilitating the activation of the hypothalamic-pituitary-adrenal (HPA axis and the autonomic nervous system in response to stress. Moreover, chronic stress enhances function of the amygdala and promotes neural plasticity throughout the amygdaloid complex. This review outlines the latest findings obtained from human studies and animal models related to the role of the emotional brain in the regulation of enteric function, specifically how increasing the gain of the amygdala to induce anxiety-like behavior using corticosterone (CORT or chronic stress increases responsiveness to both visceral and somatic stimuli in rodents. A focus of the review is the relative importance of mineralocorticoid receptor (MR and glucocorticoid receptor (GR-mediated mechanisms within the amygdala in the regulation of anxiety and nociceptive behaviors that are characteristic features of IBS. This review also discusses several outstanding questions important for future research on the role of the amygdala in the generation of abnormal GI function that may lead to potential targets for new therapies to treat functional bowel disorders such as IBS.

  10. New aspects of the role of histamine in cardiovascular function: identification, characterization, and potential pathophysiological importance of H3 receptors.

    Science.gov (United States)

    Göthert, M; Garbarg, M; Hey, J A; Schlicker, E; Schwartz, J C; Levi, R

    1995-05-01

    As a result of intensive research during several decades, the distribution, function, and pathophysiological role of cardiovascular H1 and H2 receptors are well known, whereas reports on the occurrence and function of H3 receptors in blood vessels and the heart have not become available before the last 7 years (i.e., 4 years after the first description of these receptors in the central nervous system in 1983). The development of selective and potent H3 receptor agonists and antagonists was a prerequisite for convenient investigations of cardiovascular H3 receptors, which like H1 and H2 receptors are G-protein coupled but unlike them have not yet been cloned. Both in blood vessels and the heart, H3 receptors are located on noradrenergic nerve endings and upon stimulation mediate an inhibition of noradrenaline release. Whereas it remains to be clarified under which conditions the vascular H3 receptors may be stimulated by endogenous histamine, those in the heart become activated in the early phases of myocardial ischemia characterized by an increased histamine spillover. The H3 receptors in the central nervous system also appear to be of importance for the control of vascular function. Inhibitory presynaptic H3 receptors occur on trigeminal sensory C fibres supplying blood vessels in the dura mater. Release of neuropeptides from these fibres induces a neurogenic inflammation, which has been suggested to be involved in the pathogenesis of migraine. An interaction, involving presynaptic H3 receptors, between sensory C fibres and mast cells in close apposition to these fibres plays a role in the control of histamine synthesis in the dura mater.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Importância do camundongo mdx na fisiopatologia da distrofia muscular de Duchenne The importance of mdx mouse in the pathophysiology of Duchenne's muscular distrophy

    Directory of Open Access Journals (Sweden)

    Sandra Lopes Seixas

    1997-09-01

    Full Text Available O camundongo mdx desenvolve distrofia muscular recessiva ligada ao cromossoma X (locus Xp21.1 e não expressa distrofina. Embora não apresente intensa fibrose do tecido muscular e acúmulo de tecido adiposo, é considerado o modelo animal mais adequado da distrofia muscular de Duchenne. As alterações estruturais no tecido muscular associadas à mionecrose e presença do infiltrado inflamatório com predomínio de linfócitos e monócitos/macrófagos sugerem uma participação do sistema imunológico nesta miopatia. Além disso a modulação na expressão dos componentes da matriz extracelular no microambiente muscular nas várias fases da doença (início, mionecrose, regeneração indicam um papel importante do conjuntivo no direcionamento das células inflamatórias para o foco da lesão muscular. O camundongo mdx coloca-se como um excelente modelo para o estudo dos mecanismos patogenéticos da mionecrose e regeneração na distrofia muscular de Duchenne, possibilitando inclusive o desenvolvimento de estratégias terapêuticas mais adequadas.The mdx mouse develop an X-linked recessive muscular dystrophy (locus Xp21.1 and lack dystrophin expression. Despite showing less intense myofibrosis and scarce deposition of fatty tissue, mdx mice are considered an adequate animal model for studies on the pathogenesis of Duchenne-type muscular dystrophy. Marked histological alterations in the muscular tissues associated to myonecrosis and inflammatory mononuclear cell infiltrate (lymphocytes, monocytes/macrophages suggest a participation of the immune system in this myopathy. Modulation of the extracellular matrix (ECM components in the muscular tissue during all phases (onset, myonecrosis and regeneration of disease, indicate an important role for the ECM driving inflammatory cells to the foci of lesion. Therefore mdx mice should be regarded as an important tool for studies on pathogenetic mechanisms of Duchenne-type muscular dystrophy. Such

  12. [Pathophysiology of secondary hyperparathyroidism.

    Science.gov (United States)

    Kawarazaki, Hiroo

    2017-01-01

    Secondary hyperparathyroidism(SHPT)is the result of a compensatory response of the calcium phosphate homeostatic mechanism. Vitamin D deficiency and chronic kidney disease, both representative pathophysiological causes of SHPT, have been related not only to skeletal disorders but also cardiovascular diseases, ADL and QOL. This relates the importance of SHPT as a pathological cause or marker of such states.

  13. 进口焊管高频设备国产化改造%Homemade Reform of the Imported HF Welded Pipe

    Institute of Scientific and Technical Information of China (English)

    徐锦璋

    2001-01-01

    对日本TH—200SIS高频发生器的振荡管及主要元器件进行国产化替代改造,取得了成功的经验,不仅节约了资金,而且保证了设备正常运行,节约了用电,提高了产品质量,取得了良好的经济效益。%Though the replacement reform of Japan TH-200SIS Vibratory Tubeof the HF Generating Unit, rich experience was got successfully, this is not only saved the money, but also guaranteed smoothly operation of the equipment . It saves the power, improves the product quality and acquires the good economic benefit.

  14. Epidemiology and importance of renal dysfunction in heart failure patients.

    Science.gov (United States)

    Giamouzis, Gregory; Kalogeropoulos, Andreas P; Butler, Javed; Karayannis, Georgios; Georgiopoulou, Vasiliki V; Skoularigis, John; Triposkiadis, Filippos

    2013-12-01

    Renal dysfunction (RD) is a frequent comorbid condition and a major determinant of outcomes in patients with heart failure (HF). It is likely that the etiology of RD in patients with HF is much more complex than we first thought and represents a matrix of independent, albeit interacting, pathophysiological pathways with effects on both the kidney and the heart that share a common denominator: aging and inflammation. Renal dysfunction in HF has been attributed, among others, to biochemical, hormonal, and hemodynamic factors, coupled with pharmacological interventions. Regardless of the cause, the development of RD or worsening renal function is common in patients with HF, and is associated with increased morbidity and mortality. There is increasing evidence, however, that transient increases in creatinine in the setting of acute HF are not prognostically important, whereas persistent deterioration does portend a higher mortality in this patient population. In addition, congestion seems to play an important role in the course of renal deterioration, and the combination of congestion and worsening renal function is the most significant clinical prognosticator in HF patients. This review aims to provide an update on the epidemiology and prognostic significance of RD in HF patients, in both the acute and the chronic setting.

  15. Research on Multi-Layer Distributed HF Radio Network Structure

    Institute of Scientific and Technical Information of China (English)

    Hui Dai; Chun-Jiang Wang; Quan Yu

    2008-01-01

    High frequency (HF) transmission is an important communication techniques. However, conventional point-to-point transmission can be easily destroyed, which limits its utilization in practice. HF networking communication has the capability against demolishment. The network structure is one of the key factors for HF networking communication. In this paper, a novel analysis method of the network connectedness based on the eigenvalue is derived, and a multi-layer distributed HF radio network structure is proposed. Both the theore tical analysis and the computer simulation results verify that the application of the proposed network structure in the HF radio communication can improve the anti demolishment ability of the HF network efficiently.

  16. [Treatment of gunshot fractures of the lower extremity: Part 1: Incidence, importance, case numbers, pathophysiology, contamination, principles of emergency and first responder treatment].

    Science.gov (United States)

    Franke, A; Bieler, D; Wilms, A; Hentsch, S; Johann, M; Kollig, E

    2014-11-01

    Gunshot wounds are rare in Germany and are mostly the result of suicide attempts or improper handling of weapons. The resulting injuries involve extensive tissue damage and complications which are thus unique and require a differentiated approach. As trauma centers may be confronted with gunshot wounds at any time, treatment principles must be understood and regularly reevaluated. Due to Bundeswehr operations abroad and the treatment of patients from other crisis regions a total of 85 gunshot wounds in 64 patients were treated between 2005 and 2011. In the majority of cases the lower extremities were affected and we were able to carry out treatment to preserve the extremities. In this article we report on our experiences and the results of treatment of gunshot wounds to the lower extremities. This part of the article deals with the epidemiology and pathophysiology of gunshot wounds to the lower extremities. By means of an evaluation of microbiological findings in a subgroup of patients involved in a civil war (n=10), the problem of multidrug resistant pathogen contamination, colonization and infection is discussed. In addition to a description of initial and emergency treatment of gunshot wounds, measures required for further treatment and decontamination are presented. Finally, the results are discussed with reference to the literature in this field.

  17. ExtraHF survey

    DEFF Research Database (Denmark)

    Piepoli, Massimo F; Binno, Simone; Corrà, Ugo

    2015-01-01

    AIMS: In heart failure (HF), exercise training programmes (ETPs) are a well-recognized intervention to improve symptoms, but are still poorly implemented. The Heart Failure Association promoted a survey to investigate whether and how cardiac centres in Europe are using ETPs in their HF patients...... of evidence on safety or benefit was cited. When implemented, an ETP was proposed to all HF patients in only 55% of the centres, with restriction according to severity or aetiology. CONCLUSIONS: With respect to previous surveys, there is evidence of increased availability of ETPs in HF in Europe, although too...

  18. Sepsis pathophysiology and anesthetic consideration.

    Science.gov (United States)

    Yuki, Koichi; Murakami, Naoka

    2015-01-01

    Sepsis remains to be a significant health care issue associated with high mortality and healthcare cost, despite the extensive effort to better understand the pathophysiology of the sepsis. Recently updated clinical guideline for severe sepsis and septic shock, "Surviving Sepsis Campaign 2012", emphasizes the importance of early goal-directed therapy, which can be implemented in intraoperative management of sepsis patients. Herein, we review the updates of current guideline and discuss its application to anesthesic management. Furthermore, we review the recent advance in knowledge of sepsis pathophysiology, focusing on immune modulation, which may lead to new clinical therapeutic approach to sepsis.

  19. Pathophysiological mechanisms of insulin resistance

    NARCIS (Netherlands)

    Brands, M.

    2013-01-01

    In this thesis we studied pathophysiological mechanisms of insulin resistance in different conditions in humans, i.e. in obesity, during lipid infusions, after hypercaloric feeding, and glucocorticoid treatment. We focused on 3 important hypotheses that are suggested to be implicated in the pathophy

  20. Pathophysiological mechanisms of insulin resistance

    NARCIS (Netherlands)

    Brands, M.

    2013-01-01

    In this thesis we studied pathophysiological mechanisms of insulin resistance in different conditions in humans, i.e. in obesity, during lipid infusions, after hypercaloric feeding, and glucocorticoid treatment. We focused on 3 important hypotheses that are suggested to be implicated in the pathophy

  1. Pathophysiological mechanisms of insulin resistance

    NARCIS (Netherlands)

    Brands, M.

    2013-01-01

    In this thesis we studied pathophysiological mechanisms of insulin resistance in different conditions in humans, i.e. in obesity, during lipid infusions, after hypercaloric feeding, and glucocorticoid treatment. We focused on 3 important hypotheses that are suggested to be implicated in the

  2. On renal pathophysiology in preeclampsia

    NARCIS (Netherlands)

    Penning, Maria Elisabeth (Marlies)

    2014-01-01

    Preeclampsia is a complication of pregnancy which can suddenly change from a relatively mild phenotype into a life-threatening situation. One of the organs that is always involved during preeclampsia is the kidney. The placenta plays an important role in the renal pathophysiology of preeclampsia. Th

  3. Collisional quenching of highly rotationally excited HF

    CERN Document Server

    Yang, Benhui; Forrey, R C; Stancil, P C; Balakrishnan, N

    2015-01-01

    Collisional excitation rate coefficients play an important role in the dynamics of energy transfer in the interstellar medium. In particular, accurate rotational excitation rates are needed to interpret microwave and infrared observations of the interstellar gas for nonlocal thermodynamic equilibrium line formation. Theoretical cross sections and rate coefficients for collisional deexcitation of rotationally excited HF in the vibrational ground state are reported. The quantum-mechanical close-coupling approach implemented in the nonreactive scattering code MOLSCAT was applied in the cross section and rate coefficient calculations on an accurate 2D HF-He potential energy surface. Estimates of rate coefficients for H and H$_2$ colliders were obtained from the HF-He collisional data with a reduced-potential scaling approach. The calculation of state-to-state rotational quenching cross sections for HF due to He with initial rotational levels up to $j=20$ were performed for kinetic energies from 10$^{-5}$ to 15000...

  4. Pathophysiological importance of aggregated damaged proteins.

    Science.gov (United States)

    Höhn, Annika; Jung, Tobias; Grune, Tilman

    2014-06-01

    Reactive oxygen species (ROS) are formed continuously in the organism even under physiological conditions. If the level of ROS in cells exceeds the cellular defense capacity, components such as RNA/DNA, lipids, and proteins are damaged and modified, thus affecting the functionality of organelles as well. Proteins are especially prominent targets of various modifications such as oxidation, glycation, or conjugation with products of lipid peroxidation, leading to the alteration of their biological function, nonspecific interactions, and the production of high-molecular-weight protein aggregates. To ensure the maintenance of cellular functions, two proteolytic systems are responsible for the removal of oxidized and modified proteins, especially the proteasome and organelles, mainly the autophagy-lysosomal systems. Furthermore, increased protein oxidation and oxidation-dependent impairment of proteolytic systems lead to an accumulation of oxidized proteins and finally to the formation of nondegradable protein aggregates. Accordingly, the cellular homeostasis cannot be maintained and the cellular metabolism is negatively affected. Here we address the current knowledge of protein aggregation during oxidative stress, aging, and disease.

  5. On renal pathophysiology in preeclampsia

    OpenAIRE

    2014-01-01

    Preeclampsia is a complication of pregnancy which can suddenly change from a relatively mild phenotype into a life-threatening situation. One of the organs that is always involved during preeclampsia is the kidney. The placenta plays an important role in the renal pathophysiology of preeclampsia. The placenta produces excessive amounts of anti-angiogenic factors which are associated with systemic endothelial dysfunction. Although the underlying mechanisms of renal injury during preeclampsia r...

  6. Sepsis Pathophysiology and Anesthetic Consideration

    OpenAIRE

    Yuki, Koichi; Murakami, Naoka

    2015-01-01

    Sepsis remains to be a significant health care issue associated with high mortality and healthcare cost, despite the extensive effort to better understand the pathophysiology of the sepsis. Recently updated clinical guideline for severe sepsis and septic shock, “Surviving Sepsis Campaign 2012”, emphasizes the importance of early goal-directed therapy, which can be implemented in intraoperative management of sepsis patients. Herein, we review the updates of current guideline and discuss its ap...

  7. Hypertension: physiology and pathophysiology.

    Science.gov (United States)

    Hall, John E; Granger, Joey P; do Carmo, Jussara M; da Silva, Alexandre A; Dubinion, John; George, Eric; Hamza, Shereen; Speed, Joshua; Hall, Michael E

    2012-10-01

    Despite major advances in understanding the pathophysiology of hypertension and availability of effective and safe antihypertensive drugs, suboptimal blood pressure (BP) control is still the most important risk factor for cardiovascular mortality and is globally responsible for more than 7 million deaths annually. Short-term and long-term BP regulation involve the integrated actions of multiple cardiovascular, renal, neural, endocrine, and local tissue control systems. Clinical and experimental observations strongly support a central role for the kidneys in the long-term regulation of BP, and abnormal renal-pressure natriuresis is present in all forms of chronic hypertension. Impaired renal-pressure natriuresis and chronic hypertension can be caused by intrarenal or extrarenal factors that reduce glomerular filtration rate or increase renal tubular reabsorption of salt and water; these factors include excessive activation of the renin-angiotensin-aldosterone and sympathetic nervous systems, increased formation of reactive oxygen species, endothelin, and inflammatory cytokines, or decreased synthesis of nitric oxide and various natriuretic factors. In human primary (essential) hypertension, the precise causes of impaired renal function are not completely understood, although excessive weight gain and dietary factors appear to play a major role since hypertension is rare in nonobese hunter-gathers living in nonindustrialized societies. Recent advances in genetics offer opportunities to discover gene-environment interactions that may also contribute to hypertension, although success thus far has been limited mainly to identification of rare monogenic forms of hypertension. © 2012 American Physiological Society

  8. [Sickle cell pathophysiology].

    Science.gov (United States)

    Renaudier, P

    2014-11-01

    Sickle cell disease is associated with the inversion of one base pair (A = T → A = T). The sixth codon of the beta globin chain [GAA] becomes [GTA]. Accordingly, the sixth amino acid (glutamic acid, negatively charged) is replaced by valine, hydrophobic. A hydrophobic site is present on the outside of the HbS β chain. This incurs a hydrophobic bond with the phenylalanine in position 85 and leucine in position 88, in which outsource deoxy haemoglobin. Therefore, it creates a HbS polymer that deforms the red blood cell and causes vaso-occlusive crisis in the capillary venous pole. In this conventional design, the roles are added to the nitrogen monoxide and vascular tone, the increase in adhesion of red blood cells to the endothelium damage caused by red blood cells HbS: dehydration, senescence, formation of microvesicles. If these advances in our understanding of the pathophysiology have not yet had a clinical application, they will happen one day. It is therefore particularly important to pursue in France the network structure of sickle cell disease with a view to set up multicenter trials when the day comes.

  9. Frederiksberg HF kursus

    DEFF Research Database (Denmark)

    Lindstrøm, Maria Duclos

    2008-01-01

    Notatet bygger på et interviewmateriale med dimitterede HF-kursister 3 måneder efter endt eksamen. Notatet undersøger dels, hvad der har hjulpet til at gennemføre, dels hvad der har været negativt og vanskeligt ved uddannelsen. Endvidere belyser notatet hvad kursisterne oplever at tage med fra de...

  10. Mitigating Doppler shift effect in HF multitone data modem

    Science.gov (United States)

    Sonlu, Yasar

    1989-09-01

    Digital communications over High Frequency (HF) radio channels are getting important in recent years. Current HF requirements are for data transmission at rates 2.4 kbps or more to accommodate computer data links and digital secure voice. HF modems which were produced to meet these speeds are, serial modems and parallel modems. On the other hand, the HF sky-wave communication medium, the ionosphere, has some propagation problems such as multipath and Doppler shift. The effect of Doppler shift in a parallel modem which employs Differential Quadrature Phase Shift Keying (DQPSK) modulation is considered and a correction method to mitigate the Doppler Shift effect is introduced.

  11. Pathophysiology of heart failure.

    Science.gov (United States)

    Chiariello, M; Perrone-Filardi, P

    1999-01-01

    Heart failure is a leading cause of mortality and morbidity in Western countries. Common etiology is mostly represented by ischemic and hypertensive heart disease. Clinically, heart failure can be defined as an impaired cardiac performance, unable to meet the energy requirements of the periphery. Pathophysiologically, the clinical onset of heart failure symptoms already represents an advanced stage of disease when compensatory mechanisms triggered by the underlying decrease in contractility are no longer capable of maintaining adequate cardiac performance during exercise and, subsequently, under resting conditions. Independent of its underlying etiology, cardiac failure is always characterized by an impairment in the intrinsic contractility of myocytes. As a consequence of reduced contractility, a number of central and peripheral compensatory mechanisms take place that are capable of effectively counteracting reduced intravascular intrinsic performance for a long period of time. Among them, recruitment of preload reserve, enhanced neurohormonal stimulation and cardiac hypertrophy are the most important. All of them, however, also carry unfavorable effects that contribute to further deterioration of cardiac function. In fact, increased end-diastolic volume determines increased wall stress that further reduces systolic performance; sympathetic and angiotensin stimulation increases peripheral resistance and contributes to increase volume expansion; hypertrophic myocytes demonstrate impaired intrinsic contractility and relaxation, and hypertrophy causes a clinically relevant deterioration of ventricular relaxation and compliance that substantially participates in increased end-diastolic pressure, and, therefore, to limited exercise performance. Diastolic dysfunction usually accompanies systolic dysfunction, although in some cases it may represent the prevalent mechanism of congestive heart failure in patients in whom systolic performance is preserved. Biological causes

  12. Pathophysiology of migraine

    Directory of Open Access Journals (Sweden)

    Peter J Goadsby

    2012-01-01

    Full Text Available Migraine is a common disabling brain disorder whose pathophysiology is now being better understood. The study of anatomy and physiology of pain producing structures in the cranium and the central nervous system modulation of the input have led to the conclusion that migraine involves alterations in the sub-cortical aminergic sensory modulatory systems that influence the brain widely.

  13. Microstructural characterization of as-cast hf-b alloys

    Directory of Open Access Journals (Sweden)

    João Carlos Jânio Gigolotti

    2012-04-01

    Full Text Available An accurate knowledge of several metal-boron phase diagrams is important to evaluation of higher order systems such as metal-silicon-boron ternaries. The refinement and reassessment of phase diagram data is a continuous work, thus the reevaluation of metal-boron systems provides the possibility to confirm previous data from an investigation using higher purity materials and better analytical techniques. This work presents results of rigorous microstructural characterization of as-cast hafnium-boron alloys which are significant to assess the liquid composition associated to most of the invariant reactions of this system. Alloys were prepared by arc melting high purity hafnium (minimum 99.8% and boron (minimum 99.5% slices under argon atmosphere in water-cooled copper crucible with non consumable tungsten electrode and titanium getter. The phases were identified by scanning electron microscopy, using back-scattered electron image mode and X-ray diffraction. In general, a good agreement was found between our data and those from the currently accepted Hafnium-Boron phase diagram. The phases identified are αHfSS and B-RhomSS, the intermediate compounds HfB and HfB2 and the liquide L. The reactions are the eutectic L ⇔ αHfSS + HfB and L ⇔ HfB2 + B-Rhom, the peritectic L + HfB2 ⇔ HfB and the congruent formation of HfB2.

  14. Obesity: pathophysiology and intervention.

    Science.gov (United States)

    Zhang, Yi; Liu, Ju; Yao, Jianliang; Ji, Gang; Qian, Long; Wang, Jing; Zhang, Guansheng; Tian, Jie; Nie, Yongzhan; Zhang, Yi Edi; Gold, Mark S; Liu, Yijun

    2014-11-18

    Obesity presents a major health hazard of the 21st century. It promotes co-morbid diseases such as heart disease, type 2 diabetes, obstructive sleep apnea, certain types of cancer, and osteoarthritis. Excessive energy intake, physical inactivity, and genetic susceptibility are main causal factors for obesity, while gene mutations, endocrine disorders, medication, or psychiatric illnesses may be underlying causes in some cases. The development and maintenance of obesity may involve central pathophysiological mechanisms such as impaired brain circuit regulation and neuroendocrine hormone dysfunction. Dieting and physical exercise offer the mainstays of obesity treatment, and anti-obesity drugs may be taken in conjunction to reduce appetite or fat absorption. Bariatric surgeries may be performed in overtly obese patients to lessen stomach volume and nutrient absorption, and induce faster satiety. This review provides a summary of literature on the pathophysiological studies of obesity and discusses relevant therapeutic strategies for managing obesity.

  15. Pathophysiology of the Pericardium.

    Science.gov (United States)

    Hoit, Brian D

    Pericardial heart disease includes pericarditis, (an acute, subacute, or chronic fibrinous, noneffusive, or exudative process), and its complications, constriction, (an acute, subacute, or chronic adhesive or fibrocalcific response), and cardiac tamponade. The pathophysiology of cardiac tamponade and constrictive pericarditis readily explains their respective findings on clinical examination, Doppler echocardiography, and at cardiac catheterization. The primary abnormality of cardiac tamponade is pan-cyclic compression of the cardiac chambers by increased pericardial fluid requiring that cardiac chambers compete for a fixed intrapericardial volume. Features responsible for the pathophysiology include transmission of thoracic pressure through the pericardium and heightened ventricular interdependence. Constrictive pericarditis is a condition in which the pericardium limits diastolic filling and causes dissociation of intracardiac and intrathoracic pressures, and heightened ventricular interdependence. Both conditions result in diastolic dysfunction, elevated and equal venous and ventricular diastolic pressure, respiratory variation in ventricular filling, and ultimately, reduced cardiac output. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Obesity: Pathophysiology and Intervention

    Directory of Open Access Journals (Sweden)

    Yi Zhang

    2014-11-01

    Full Text Available Obesity presents a major health hazard of the 21st century. It promotes co-morbid diseases such as heart disease, type 2 diabetes, obstructive sleep apnea, certain types of cancer, and osteoarthritis. Excessive energy intake, physical inactivity, and genetic susceptibility are main causal factors for obesity, while gene mutations, endocrine disorders, medication, or psychiatric illnesses may be underlying causes in some cases. The development and maintenance of obesity may involve central pathophysiological mechanisms such as impaired brain circuit regulation and neuroendocrine hormone dysfunction. Dieting and physical exercise offer the mainstays of obesity treatment, and anti-obesity drugs may be taken in conjunction to reduce appetite or fat absorption. Bariatric surgeries may be performed in overtly obese patients to lessen stomach volume and nutrient absorption, and induce faster satiety. This review provides a summary of literature on the pathophysiological studies of obesity and discusses relevant therapeutic strategies for managing obesity.

  17. [Pathophysiology of hemorragic shock].

    Science.gov (United States)

    Copotoiu, R; Cinca, E; Collange, O; Levy, F; Mertes, P-M

    2016-11-01

    This review addresses the pathophysiology of hemorrhagic shock, a condition produced by rapid and significant loss of intravascular volume, which may lead to hemodynamic instability, decreases in oxygen delivery, decreased tissue perfusion, cellular hypoxia, organ damage, and death. The initial neuroendocrine response is mainly a sympathetic activation. Haemorrhagic shock is associated altered microcirculatory permeability and visceral injury. It is also responsible for a complex inflammatory response associated with hemostasis alteration. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  18. Pathophysiology of cancer cachexia

    OpenAIRE

    Younes Riad N.; Noguchi Yoshikazu

    2000-01-01

    Cancer cachexia is a frequent complication observed in patients with malignant tumors. Although several decades have passed since the first focus on the metabolic dysfunction's associated with cancer, few effective therapeutic interventions have been successfully introduced into the medical armamentarium. The present study thoroughly reviews the basic pathophysiology of cancer cachexia and the treatment options already investigated in that field. Experimental and clinical studies were evaluat...

  19. Recent Advances on Pathophysiology, Diagnostic and Therapeutic Insights in Cardiac Dysfunction Induced by Antineoplastic Drugs

    Directory of Open Access Journals (Sweden)

    Marilisa Molinaro

    2015-01-01

    Full Text Available Along with the improvement of survival after cancer, cardiotoxicity due to antineoplastic treatments has emerged as a clinically relevant problem. Potential cardiovascular toxicities due to anticancer agents include QT prolongation and arrhythmias, myocardial ischemia and infarction, hypertension and/or thromboembolism, left ventricular (LV dysfunction, and heart failure (HF. The latter is variable in severity, may be reversible or irreversible, and can occur soon after or as a delayed consequence of anticancer treatments. In the last decade recent advances have emerged in clinical and pathophysiological aspects of LV dysfunction induced by the most widely used anticancer drugs. In particular, early, sensitive markers of cardiac dysfunction that can predict this form of cardiomyopathy before ejection fraction (EF is reduced are becoming increasingly important, along with novel therapeutic and cardioprotective strategies, in the attempt of protecting cardiooncologic patients from the development of congestive heart failure.

  20. Recent Advances on Pathophysiology, Diagnostic and Therapeutic Insights in Cardiac Dysfunction Induced by Antineoplastic Drugs

    Science.gov (United States)

    Molinaro, Marilisa; Marone, Giancarlo; Abete, Pasquale; Di Lisa, Fabio; De Placido, Sabino; Bonaduce, Domenico; Tocchetti, Carlo G.

    2015-01-01

    Along with the improvement of survival after cancer, cardiotoxicity due to antineoplastic treatments has emerged as a clinically relevant problem. Potential cardiovascular toxicities due to anticancer agents include QT prolongation and arrhythmias, myocardial ischemia and infarction, hypertension and/or thromboembolism, left ventricular (LV) dysfunction, and heart failure (HF). The latter is variable in severity, may be reversible or irreversible, and can occur soon after or as a delayed consequence of anticancer treatments. In the last decade recent advances have emerged in clinical and pathophysiological aspects of LV dysfunction induced by the most widely used anticancer drugs. In particular, early, sensitive markers of cardiac dysfunction that can predict this form of cardiomyopathy before ejection fraction (EF) is reduced are becoming increasingly important, along with novel therapeutic and cardioprotective strategies, in the attempt of protecting cardiooncologic patients from the development of congestive heart failure. PMID:26583088

  1. Pathophysiology of Equine Neonatal Septicemia

    Directory of Open Access Journals (Sweden)

    Juan Carlos Ospina Chirivi

    2014-07-01

    Full Text Available Neonatal septicemia is a major cause of mortality and morbidity in horses in their first seven days of life and within their pathophysiology. It is important to consider the extrinsic and intrinsic predisposing factors which make foals susceptible to agents of primarily bacterial etiology. However, other types of infectious etiology (viruses and fungi should be considered too, as well as noninfectious etiologies. The paper mentions a wide variety of mechanisms that produce different injuries that must be addressed with measures of critical neonatal care, so it is imperative for the veterinarian to know the pathogenic mechanisms of the disease, its clinical presentation and anatomo-pathological lesions. Thus, systemic inflammatory response syndrome (SIRS, multiple organ dysfunction syndrome (MODS, and peripheral circulatory collapse or shock are some of the elements defined as the pillars of the pathophysiology of neonatal septicemia, extensively studied in equine medicine. This paper presents a short review of the triggering mechanisms of neonatal septicemia highlighting the importance of epidemiological investigations in Colombia. It shows the need for retrospective and prospective studies and for divulgation of some of the preventive measures of the disease in horses.

  2. Suppression Factor of ~(182)W for ~(182)Hf AMS at CIAE

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Suppression factor of 182W is an important index in the measurement of 182Hf with AMS method. This factor is defined as the value of 182W/180Hf in blank samples divised by the measured value of 182 W/180Hf with AMS method. In order to satisfy a

  3. Pulsed inductive HF laser

    Energy Technology Data Exchange (ETDEWEB)

    Razhev, A M; Kargapol' tsev, E S [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation); Churkin, D S; Demchuk, S V [Novosibirsk State University, Novosibirsk (Russian Federation)

    2016-03-31

    We report the results of experimentally investigated dependences of temporal, spectral and spatial characteristics of an inductive HF-laser generation on the pump conditions. Gas mixtures H{sub 2} – F{sub 2}(NF{sub 3} or SF6{sub 6}) and He(Ne) – H{sub 2} – F{sub 2}(NF{sub 3} or SF{sub 6}) were used as active media. The FWHM pulse duration reached 0.42 μs. This value corresponded to a pulsed power of 45 kW. For the first time, the emission spectrum of an inductive HF laser was investigated, which consisted of seven groups of bands with centres around the wavelengths of 2732, 2736, 2739, 2835, 2837, 2893 and 2913 nm. The cross section profile of the laser beam was a ring with a diameter of about 20 mm and width of about 5 mm. Parameters of laser operation in the repetitively pulsed regime were sufficiently stable. The amplitude instability of light pulses was no greater than 5% – 6%. (lasers)

  4. [Functional pathophysiology of consciousness].

    Science.gov (United States)

    Jellinger, Kurt A

    2009-01-01

    from important somatic and sensory pathways and acts as a control system of neuronal activities of the cerebral cortex. The principal function of the ARAS is to focus our alertness on specific stimuli or internal processes, which run via complex neuronal cell groups and numerous neurotransmitters that influence various aspects of consciousness and wakefulness. Stimulation of the ARAS produces an arousal reaction as the electric correlate of consciousness; its destruction causes coma and related states. The highest level are cortical (prefrontal and association) networks for recognition, motor activity, longterm memory and attention, the left hemisphere being considered as the dominant one. Different levels of consciousness are distinguished: 1. hyperalertness, 2. alertness (normal state of wakefulness), 3. somnolence or lethargy, 4. obtundation with tendency to fall asleep, 5. stupor, 6. coma and its subtypes, like akinetic mutism, apallic syndrome or persistent vegative state, locked-in syndrome, delirium, and catatonia. They are caused by damages in various functional levels of the brain, by psychogenic factors or experimentally, and are accompanied by characteristic neurological and psychiatric disorders. The relevant morphological lesions can be detected by electrophysiological and imaging studies. The bases of functional anatomy and pathophysiology of consciousness, its cognitive aspects and its major disorders, their causes and functional substrates with reference to sleep and both spontaneous and iatrogenic disorders of consciousness are critically summarized.

  5. Pathophysiology of the Belgrade Rat

    Directory of Open Access Journals (Sweden)

    Tania eVeuthey

    2014-04-01

    Full Text Available The Belgrade rat is an animal model of Divalent Metal Transporter-1 (DMT1 deficiency. This strain originates from an X-irradiation experiment first reported in 1966. Since then, the Belgrade rat’s pathophysiology has helped to reveal the importance of iron balance and the role of DMT1. This review discusses our current understanding of iron transport homeostasis and summarizes molecular details of DMT1 function. We describe how studies of the Belgrade rat have revealed key roles for DMT1 in iron distribution to red blood cells as well as duodenal iron absorption. The Belgrade rat’s pathology has extended our knowledge of hepatic iron handling, pulmonary and olfactory iron transport as well as brain iron uptake and renal iron handling. For example, relationships between iron and manganese metabolism have been discerned since both are essential metals transported by DMT1. Pathophysiologic features of the Belgrade rat provide us with a unique and interesting animal model to understand iron homeostasis.

  6. The "chloride theory", a unifying hypothesis for renal handling and body fluid distribution in heart failure pathophysiology.

    Science.gov (United States)

    Kataoka, Hajime

    2017-07-01

    Body fluid volume regulation is a complex process involving the interaction of various afferent (sensory) and neurohumoral efferent (effector) mechanisms. Historically, most studies focused on the body fluid dynamics in heart failure (HF) status through control of the balance of sodium, potassium, and water in the body, and maintaining arterial circulatory integrity is central to a unifying hypothesis of body fluid regulation in HF pathophysiology. The pathophysiologic background of the biochemical determinants of vascular volume in HF status, however, has not been known. I recently demonstrated that changes in vascular and red blood cell volumes are independently associated with the serum chloride concentration, but not the serum sodium concentration, during worsening HF and its recovery. Based on these observations and the established central role of chloride in the renin-angiotensin-aldosterone system, I propose a unifying hypothesis of the "chloride theory" for HF pathophysiology, which states that changes in the serum chloride concentration are the primary determinant of changes in plasma volume and the renin-angiotensin-aldosterone system under worsening HF and therapeutic resolution of worsening HF. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Imaging Alzheimer's disease pathophysiology with PET

    Directory of Open Access Journals (Sweden)

    Lucas Porcello Schilling

    Full Text Available ABSTRACT Alzheimer's disease (AD has been reconceptualised as a dynamic pathophysiological process characterized by preclinical, mild cognitive impairment (MCI, and dementia stages. Positron emission tomography (PET associated with various molecular imaging agents reveals numerous aspects of dementia pathophysiology, such as brain amyloidosis, tau accumulation, neuroreceptor changes, metabolism abnormalities and neuroinflammation in dementia patients. In the context of a growing shift toward presymptomatic early diagnosis and disease-modifying interventions, PET molecular imaging agents provide an unprecedented means of quantifying the AD pathophysiological process, monitoring disease progression, ascertaining whether therapies engage their respective brain molecular targets, as well as quantifying pharmacological responses. In the present study, we highlight the most important contributions of PET in describing brain molecular abnormalities in AD.

  8. HF Interference, Procedures and Tools (Interferences HF, procedures et outils)

    Science.gov (United States)

    2007-06-01

    such sources. The existing HF background noise possibly may be increased via ground wave and/or sky wave propagation. Increase of the existing HF...télécommunications filaires à large bande. Les télécommunications via le réseau électrique courant, dites PowerLine Communications (PLT ou PLC) et diverses...cumulative de nombreuses sources de même type. Le bruit de fond HF existant risque d’être augmenté par propagation de l’onde terrestre et/ou aérienne

  9. Reform in teaching preclinical pathophysiology.

    Science.gov (United States)

    Li, Yong-Yu; Li, Kun; Yao, Hong; Xu, Xiao-Juan; Cai, Qiao-Lin

    2015-12-01

    Pathophysiology is a scientific discipline that studies the onset and progression of pathological conditions and diseases, and pathophysiology is one of the core courses in most preclinical medical curricula. In China, most medical schools house a Department of Pathophysiology, in contrast to medical schools in many developed countries. The staff in Chinese Departments of Pathophysiology generally consists of full-time instructors or lecturers who teach medical students. These lecturers are sometimes lacking in clinic knowledge and experiences. To overcome this, in recent years, we have been trying to bring new trends in teaching pathophysiology into our curriculum. Our purpose in writing this article was to share our experiences with our colleagues and peers worldwide in the hope that the insights we have gained in pathophysiology teaching will be of some value to educators who advocate teaching reform in medical schools.

  10. [Pruritus: considerable progress in pathophysiology].

    Science.gov (United States)

    Misery, Laurent

    2014-12-01

    Pruritus is defined as "an unpleasant sensation that causes the need to scratch". This is not a small pain. It seems that pruriceptors exist but their level of separation from nociceptive receptors is still debated. Pathways of pruritus were identified from the skin (around the dermo-epidermal junction) to the brain. Many mediators are involved in pruritus but there are at least a histaminergic and a non-histaminergic pathway (PAR-2dependent). Similarly to pain, gate control or peripheral and central sensitization mechanisms have been highlighted in pruritus. These pathophysiological advances are important and anticipate therapeutic advances, that will be very useful for the symptomatic treatment of pruritus (poorly efficient at present).

  11. Heart Failure with Preserved Ejection Fraction – Concept, Pathophysiology, Diagnosis and Challenges for Treatment

    Directory of Open Access Journals (Sweden)

    Lidija Veterovska Miljkovik

    2015-07-01

    Full Text Available Heart failure (HF with preserved left ventricular (LV ejection fraction (HFpEF occurs in 40 to 60% of the patients with HF, with a prognosis which is similar to HF with reduced ejection fraction (HFrEF. HFpEF pathophysiology is different from that of HFrEF, and has been characterized with diastolic dysfunction. Diastolic dysfunction has been defined with elevated left ventricular stiffness, prolonged iso-volumetric LV relaxation, slow LV filing and elevated LV end-diastolic pressure. Arterial hypertension occurs in majority cases with HFpEF worldwide. Patients are mostly older and obese. Diabetes mellitus and atrial fibrillation appear proportionally in a high frequency of patients with HFpEF. The HFpEF diagnosis is based on existence of symptoms and signs of heart failure, normal or approximately normal ejection and diagnosing of LV diastolic dysfunction by means of heart catheterization or Doppler echocardiography and/or elevated concentration of plasma natriuretic peptide. The present recommendations for HFpEF treatment include blood pressure control, heart chamber frequency control when atrial fibrillation exists, in some situations even coronary revascularization and an attempt for sinus rhythm reestablishment. Up to now, it is considered that no medication or a group of medications improve the survival of HFpEF patients. Due to these causes and the bad prognosis of the disorder, rigorous control is recommended of the previously mentioned precipitating factors for this disorder. This paper presents a universal review of the most important parameters which determine this disorder.

  12. Pathophysiology of Takotsubo Syndrome.

    Science.gov (United States)

    Pelliccia, Francesco; Kaski, Juan Carlos; Crea, Filippo; Camici, Paolo G

    2017-06-13

    Originally described by Japanese authors in the 1990s, Takotsubo syndrome (TTS) generally presents as an acute myocardial infarction characterized by severe left ventricular dysfunction. TTS, however, differs from an acute coronary syndrome because patients have generally a normal coronary angiogram and left ventricular dysfunction, which extends beyond the territory subtended by a single coronary artery and recovers within days or weeks. The prognosis was initially thought to be benign, but subsequent studies have demonstrated that both short-term mortality and long-term mortality are higher than previously recognized. Indeed, mortality reported during the acute phase in hospitalized patients is ≈4% to 5%, a figure comparable to that of ST-segment-elevation myocardial infarction in the era of primary percutaneous coronary interventions. Despite extensive research, the cause and pathogenesis of TTS remain incompletely understood. The aim of the present review is to discuss the pathophysiology of TTS with particular emphasis on the role of the central and autonomic nervous systems. Different emotional or psychological stressors have been identified to precede the onset of TTS. The anatomic structures that mediate the stress response are found in both the central and autonomic nervous systems. Acute stressors induce brain activation, increasing bioavailability of cortisol and catecholamine. Both circulating epinephrine and norepinephrine released from adrenal medullary chromaffin cells and norepinephrine released locally from sympathetic nerve terminals are significantly increased in the acute phase of TTS. This catecholamine surge leads, through multiple mechanisms, that is, direct catecholamine toxicity, adrenoceptor-mediated damage, epicardial and microvascular coronary vasoconstriction and/or spasm, and increased cardiac workload, to myocardial damage, which has a functional counterpart of transient apical left ventricular ballooning. The relative preponderance

  13. Fisiopatologia da enxaqueca Migraine pathophysiology

    Directory of Open Access Journals (Sweden)

    MAURICE B. VINCENT

    1998-12-01

    Full Text Available A fisiopatologia da enxaqueca ainda não foi completamente elucidada. As principais estruturas envolvidas parecem ser o sistema nervoso central (córtex e tronco cerebral, o sistema trigeminovascular e os vasos correspondentes, outras fibras autonômicas que inervam estes vasos, e os vários agentes vasoativos locais, como a SP, CGRP, NO, VIP, NPY, ACh, NA, NKA, entre outros. A depressão alastrante é o fenômeno neurológico que provavelmente justifica achados experimenais e clínicos na enxaqueca. Ela tem velocidade de propagação semelhante à aura, ativa o núcleo espinhal do trigêmeo e está relacionada à liberação de CGRP e NO. Alterações circulatórias detectadas por métodos complementares reforçam o papel da depressão alastrante. A identificação de anormalidades em pelo menos três loci (cromossomas 19 e 1 na enxaqueca hemiplégica familiar ocorreu recentemente. Elas estão relacionadas a anormalidades nos canais de cálcio voltagem dependentes tipo P/Q, específicos do sistema nervoso central, que regulam a liberação de vários neurotransmissores, incluindo possivelmente a serotonina. A exemplo de outras anormalidades neurológicas paroxísticas que resultam da hiperexcitabilidade da membrana plasmática, é possível que a enxaqueca ocorra devido a uma desordem de canais iônicos.The pathophysiology of migraine is not yet fully understood. The most important structures involved seem to be the central nervous system (cortex and brain stem, the trigeminovascular system and related cranial arteries, other autonomic fibres innervating such vessels, and various local vasoactive agents, including SP, CGRP, NO, VIP, NPY, ACh, NA, NKA, among others. The spreading depression phenomenon may explain clinical as well experimental findings in migraine. Its propagation velocity mirrors what is found in clinical aura, it may activate the spinal trigeminal nucleus and may induce CGRP and NO release. Circulatory changes detected with

  14. Marburg Hemorrhagic Fever (Marburg HF)

    Science.gov (United States)

    ... CDC Cancel Submit Search The CDC Marburg hemorrhagic fever (Marburg HF) Note: Javascript is disabled or is ... first recognized in 1967, when outbreaks of hemorrhagic fever occurred simultaneously in laboratories in Marburg and Frankfurt, ...

  15. Pathophysiology of nasal congestion

    Directory of Open Access Journals (Sweden)

    Robert M Naclerio

    2010-02-01

    Full Text Available Robert M Naclerio1, Claus Bachert2, James N Baraniuk31University of Chicago, Department of Surgery, Section of Otolaryngology – Head and Neck Surgery, Chicago, Illinois, USA; 2University of Ghent, Ghent, Belgium; 3Georgetown University, Washington, DC, USAAbstract: Nasal congestion is a common symptom in rhinitis (both allergic and nonallergic, rhinosinusitis and nasal polyposis. Congestion can also be caused by physical obstruction of nasal passages and/or modulation of sensory perception. Mucosal inflammation underlies many of the specific and interrelated factors that contribute to nasal congestion, as well as other symptoms of both allergic rhinitis and rhinosinusitis. A wide range of biologically active agents (eg, histamine, tumor necrosis factor-α, interleukins, cell adhesion molecules and cell types contribute to inflammation, which can manifest as venous engorgement, increased nasal secretions and tissue swelling/edema, ultimately leading to impaired airflow and the sensation of nasal congestion. Inflammation-induced changes in the properties of sensory afferents (eg, expression of peptides and receptors that innervate the nose can also contribute to altered sensory perception, which may result in a subjective feeling of congestion. Increased understanding of the mechanisms underlying inflammation can facilitate improved treatment selection and the development of new therapies for congestion.Keywords: allergic rhinitis, congestion, obstruction, pathophysiology, rhinosinusitis

  16. The pathophysiology of concussion.

    Science.gov (United States)

    Signoretti, Stefano; Lazzarino, Giuseppe; Tavazzi, Barbara; Vagnozzi, Roberto

    2011-10-01

    Concussion is defined as a biomechanically induced brain injury characterized by the absence of gross anatomic lesions. Early and late clinical symptoms, including impairments of memory and attention, headache, and alteration of mental status, are the result of neuronal dysfunction mostly caused by functional rather than structural abnormalities. The mechanical insult initiates a complex cascade of metabolic events leading to perturbation of delicate neuronal homeostatic balances. Starting from neurotoxicity, energetic metabolism disturbance caused by the initial mitochondrial dysfunction seems to be the main biochemical explanation for most postconcussive signs and symptoms. Furthermore, concussed cells enter a peculiar state of vulnerability, and if a second concussion is sustained while they are in this state, they may be irreversibly damaged by the occurrence of swelling. This condition of concussion-induced brain vulnerability is the basic pathophysiology of the second impact syndrome. N-acetylaspartate, a brain-specific compound representative of neuronal metabolic wellness, is proving a valid surrogate marker of the post-traumatic biochemical damage, and its utility in monitoring the recovery of the aforementioned "functional" disturbance as a concussion marker is emerging, because it is easily detectable through proton magnetic resonance spectroscopy. Copyright © 2011 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  17. REMPI Spectroscopy of HfF

    CERN Document Server

    Loh, Huanqian; Yahn, Tyler S; Looser, Herbert; Field, Robert W; Cornell, Eric A

    2012-01-01

    The spectrum of electronic states at 30000--33000 cm$^{-1}$ in hafnium fluoride has been studied using (1+1) resonance-enhanced multi-photon ionization (REMPI) and (1+1$'$) REMPI. Six $\\Omega' = 3/2$ and ten $\\Pi_{1/2}$ vibronic bands have been characterized. We report the molecular constants for these bands and estimate the electronic energies of the excited states using a correction derived from the observed isotope shifts. When either of two closely spaced $\\Pi_{1/2}$ electronic states is used as an intermediate state to access autoionizing Rydberg levels, qualitatively distinct autoionization spectra are observed. The intermediate state-specificity of the autoionization spectra bodes well for the possibility of using a selected $\\Pi_{1/2}$ state as an intermediate state to create ionic HfF$^+$ in various selected quantum states, an important requirement for our electron electric dipole moment (eEDM) search in HfF$^+$.

  18. Hf Transition Probabilities and Abundances

    CERN Document Server

    Lawler, J E; Labby, Z E; Sneden, C; Cowan, J J; Ivans, I I

    2006-01-01

    Radiative lifetimes from laser-induced fluorescence measurements, accurate to about +/- 5 percent, are reported for 41 odd-parity levels of Hf II. The lifetimes are combined with branching fractions measured using Fourier transform spectrometry to determine transition probabilities for 150 lines of Hf II. Approximately half of these new transition probabilities overlap with recent independent measurements using a similar approach. The two sets of measurements are found to be in good agreement for measurements in common. Our new laboratory data are applied to refine the hafnium photospheric solar abundance and to determine hafnium abundances in 10 metal-poor giant stars with enhanced r-process abundances. For the Sun we derive log epsilon (Hf) = 0.88 +/- 0.08 from four lines; the uncertainty is dominated by the weakness of the lines and their blending by other spectral features. Within the uncertainties of our analysis, the r-process-rich stars possess constant Hf/La and Hf/Eu abundance ratios, log epsilon (Hf...

  19. Pathophysiology of cancer cachexia

    Directory of Open Access Journals (Sweden)

    Riad N. Younes

    2000-10-01

    Full Text Available Cancer cachexia is a frequent complication observed in patients with malignant tumors. Although several decades have passed since the first focus on the metabolic dysfunction's associated with cancer, few effective therapeutic interventions have been successfully introduced into the medical armamentarium. The present study thoroughly reviews the basic pathophysiology of cancer cachexia and the treatment options already investigated in that field. Experimental and clinical studies were evaluated individually in order to clarify the intricate alterations observed in tumor-bearing patients. The difficulties in introducing sound and effective nutritional support or metabolic manipulation to reverse cancer cachexia are outlined in this review.A caquexia é uma complicação freqüentemente observada em pacientes portadores de tumores malignos. Apesar de várias décadas transcorrerem desde a descrição inicial das disfunções metabólicas associadas ao câncer, poucas medidas terapêuticas foram induzidas com sucesso na prática médica. O presente estudo apresenta uma revisão detalhada da fisiopatologia básica da caquexia em câncer, e as opções terapêuticas desenvolvidas nesta área. Estudos experimentais, assim como clínicos, são avaliados individualmente para esclarecer as alterações complexas observadas em pacientes portadores de tumores. As dificuldades encontradas para introduzir manipulações metabólicas e terapias de suporte nutricional eficientes são discutidas nesta revisão.

  20. [Pathophysiology of urticaria].

    Science.gov (United States)

    Nosbaum, A; Augey, F; Nicolas, J-F; Bérard, F

    2014-11-01

    Urticaria is a dermal edema resulting from vascular dilatation and leakage of fluid into the skin in response to molecules released from mast cells. The major mediator responsible for urticaria is histamine. However, the clinical spectrum and pattern of lesions indicate that other molecules, including prostaglandins, leukotrienes, cytokines, and chemokines, produced at different times after mast cell activation contribute to the polymorphism of this symptom and the variable evolution of this disease. It is a common practice to distinguish immunological and nonimmunological urticaria. Immunological urticaria is a hypersensitivity reaction mediated by antibodies and/or T-cells that results in mast cell activation. Although immunoglobulin (Ig) E-mediated type I hypersensitivity (HS) was long postulated to be the major immunological pathway associated with mast cell activation, interaction between IgEbound mast cells and allergens is unlikely to be the mechanism by which urticaria develops in most patients. It is now well established that urticaria may result from the binding of IgG auto-antibodies to IgE and/or to the receptor for IgE molecules on mast cells, thus corresponding to a type II HS reaction. These auto-immune urticarias represent up to 50 % of patients with chronic urticaria. Mast cell activation can also result from type III HS through the binding of circulating immune complexes to mast cell-expressing Fc receptors for IgG and IgM. Finally, under certain circumstances, T-cells can induce activation of mast cells, as well as histamine release (type IV HS). Nonimmunological urticarias result from mast cell activation through membrane receptors involved in innate immunity (e.g., complement, Toll-like, cytokine/chemokine, opioid) or by direct toxicity of xenobiotics (haptens, drugs). In conclusion, urticaria may result from different pathophysiological mechanisms that explain the great heterogeneity of clinical symptoms and the variable responses to treatment.

  1. Important role of magma mixing in generating the Mesozoic monzodioritic-granodioritic intrusions related to Cu mineralization, Tongling, East China: Evidence from petrological and in situ Sr-Hf isotopic data

    Science.gov (United States)

    Chen, C. J.; Chen, B.; Li, Z.; Wang, Z. Q.

    2016-04-01

    The Mesozoic ore-bearing high-Mg monzodioritic-granodioritic rocks in the Tongling mining district (East China) have been described as having adakitic affinities, and their origin has been attributed to partial melting of delaminated eclogite at depth in the mantle, followed by interaction of the resultant granitic magma with mantle peridotite. Here we present petrological data and in situ Sr isotopic data for zoned plagioclase that are inconsistent with the eclogite-derived model and instead propose a model that involves magma mixing of siliceous crustal melts and basaltic magma that was derived from metasomatized mantle in a back-arc extensional regime. The principal geochemical signatures of these Mesozoic rocks include a high-K calc-alkaline affinity, high values of Mg#, high Sr-Ba abundances, high Sr/Y and La/Yb ratios, εNd(t) = - 13.1 to - 9.0, and ISr = 0.70707-0.70824. The magma mixing model is supported by (1) the common existence of mafic microgranular enclaves (MMEs) and the disequilibrium textures of plagioclase and amphibole, (2) the 87Sr/86Sr ratios of embayed high-Ca cores of plagioclase that are distinctly lower than in the euhedral low-Ca overgrowth rims, (3) the negative correlations between whole-rock Nd and Sr isotopic ratios, and (4) the significant differences in the values of εHf(t) (- 9.5 to - 26) within different zircons from the same intrusion.

  2. LUPUS ANTICOAGULANTS: PATHOPHYSIOLOGY, CLINICAL AND ...

    African Journals Online (AJOL)

    2003-11-02

    Nov 2, 2003 ... clinical, laboratory, pathophysiology and management. Only data relevant to the ... pulmonary hypertension, heparin related ... anticoagulant effect of beta 2 factor Xa. .... with severe valvular heart disease in patients with and.

  3. The isobutylene-isobutane alkylation process in liquid HF revisited.

    Science.gov (United States)

    Esteves, P M; Araújo, C L; Horta, B A C; Alvarez, L J; Zicovich-Wilson, C M; Ramírez-Solís, A

    2005-07-07

    Details on the mechanism of HF catalyzed isobutylene-isobutane alkylation were investigated. On the basis of available experimental data and high-level quantum chemical calculations, a detailed reaction mechanism is proposed taking into account solvation effects of the medium. On the basis of our computational results, we explain why the density of the liquid media and stirring rates are the most important parameters to achieve maximum yield of alkylate, in agreement with experimental findings. The ab initio Car-Parrinello molecular dynamics calculations show that isobutylene is irreversibly protonated in the liquid HF medium at higher densities, leading to the ion pair formation, which is shown to be a minimum on the potential energy surface after optimization using periodic boundary conditions. The HF medium solvates preferentially the fluoride anion, which is found as solvated [FHF](-) or solvated F(-.)(HF)(3). On the other hand, the tert-butyl cation is weakly solvated, where the closest HF molecules appear at a distance of about 2.9 Angstrom with the fluorine termination of an HF chain.

  4. Important role of magma mixing in generating the Mesozoic monzodioritic-granodioritic intrusions related to Cu mineralization, Tongling, East China: evidence from petrological and in situ Sr-Hf isotopic data

    Science.gov (United States)

    Chen, Bin; Chen, ChangJian

    2016-04-01

    The Mesozoic ore-bearing high-Mg monzodioritic-granodioritic rocks in the Tongling mining district (East China) have been described as having adakitic affinities, and their origin has been attributed to partial melting of delaminated eclogite at depth in the mantle, followed by interaction of the resultant granitic magma with mantle peridotite. Here we present petrological data and in situ Sr isotopic data for zoned plagioclase that are inconsistent with the eclogite-derived model, and instead propose a model that involves magma mixing of siliceous crustal melts and basaltic magma that was derived from metasomatized mantle by subduction zone fluids in an extensional regime. The principal geochemical signatures of these Mesozoic rocks include a hydrous and high-K calc-alkaline affinity, high values of Mg#, high Sr abundances, high Sr/Y and La/Yb ratios, ɛNd(t)=-13.1 to -9.0, and ISr=0.70707-0.70824. The magma mixing model is supported by (1) the common existence of mafic microgranular enclaves (MMEs) and the disequilibrium textures of plagioclase and hornblende, (2) the increase in Ti and Al(IV) from hornblende cores to rims, and the overgrowths of high-Ca pyroxene around hornblende grains as well, indicative of episode of heating and rejuvenation of the magma chamber as a result of recharge of mafic magma, (3) the 87Sr/86Sr ratios of embayed high-Ca cores of plagioclase that are distinctly lower than in the euhedral low-Ca overgrowth rims, (4) negative correlations between whole-rock Nd and Sr isotopic ratios, and (5) the significant differences in the values of ɛHf(t) (-9.5 to -26) within different zircons from the same intrusion. We propose that underplating of hydrous basaltic magma from the metasomatized lithospheric mantle in the lower crust resulted in partial melting of the lower crustal rocks (Precambrian TTG gneisses and amphibolite/granulite) under water-saturated conditions, during which plagioclase decomposed, leaving hornblende-rich restites and

  5. Juvenile myoclonic epilepsy: epidemiology, pathophysiology, and management.

    Science.gov (United States)

    Welty, Timothy E

    2006-01-01

    Juvenile myoclonic epilepsy (JME) is a common epilepsy syndrome that begins most frequently in the early teenage years. It is officially classified as a type of idiopathic generalized epilepsy and is often under-recognized or misdiagnosed. This syndrome has a strong genetic component with multiple gene mutations being associated with the clinical presentation. Based upon genetic associations, there may be multiple pathophysiologic mechanisms for the disorder; the pathophysiology has not been clearly defined. A diagnosis of JME is made using the clinical history and EEG findings. Valproic acid is the primary antiepileptic drug (AED) used for JME, but some newer AEDs may be effective alternatives. Selection of an appropriate AED is essential to the proper management of JME, because of the possibility of exacerbation of seizures by some AEDs and the adverse effect profiles of effective drugs. It is important for clinicians to understand JME to correctly diagnose and manage patients with this syndrome.

  6. [Pathophysiology of hypertension: what's new?].

    Science.gov (United States)

    Büchner, Nikolaus; Vonend, Oliver; Rump, Lars Christian

    2006-06-01

    The pathophysiology of primary hypertension is still unresolved and appears more complex than ever. It is beyond the scope of this article to review all new scientific developments in this field. On clinical grounds, hypertension is divided into primary and secondary forms. Here, the authors discuss the pathophysiology of hypertension associated with three common disease entities showing a large overlap with primary hypertension: chronic kidney disease (CKD), obstructive sleep apnea (OSA), and hyperaldosteronism. Especially in CKD and OSA, the activation of the sympathetic nervous system plays a crucial role. It is the authors' belief that hypertension due to these three diseases is more common than previously appreciated and may account for about 20% of the hypertensive population. The knowledge of the underlying pathophysiology allows early diagnosis and guides optimal treatment of these hypertensive patients.

  7. Pathophysiology of the anorexia of aging.

    Science.gov (United States)

    Morley, John E

    2013-01-01

    Anorexia represents a major problem for older persons leading to weight loss, sarcopenia, functional decline, and mortality. There is increasing information on the pathophysiological mechanisms that lead to anorexia. Increasing evidence has shown the importance of gastrointestinal hormones (ghrelin, cholecystokinin, and glucagon-like peptide) and adipokines in producing the anorexia of aging. Numerous neurotransmitters have been shown to be involved in this aging anorexia, but evidence in humans is lacking. The early recognition of anorexia of aging is important to allow intervention and prevent functional deterioration in older persons. Screening tests for anorexia have been developed. New approaches to managing anorexia are being tested.

  8. Pathophysiology of merkel cell

    Directory of Open Access Journals (Sweden)

    Prashant Balasaheb Munde

    2013-01-01

    Full Text Available The objective of this review is to introduce Merkel cells (MCs, to provide a basic overview on the theoretical background of function, development and clinical importance of MCs. The origin of human MCs have been controversial. Some investigators believe that it is a neural crest derivate, whereas others have proposed that it is a differentiation product of the fetal epidermal keratinocytes. MCs are cells primarily localized in the epidermal basal layer of vertebrates and concentrated in touch-sensitive areas in glabrous, hairy skin and in some mucosa. In routine light microscopy, human MCs can hardly be identified. Cytokeratin 20 (CK20 is a reliable marker with highest degree of specificity. MCs can be also distinguished by electron microscopy. MC carcinoma (MCC is an uncommon and often aggressive malignancy and found mainly in elderly patients. It occurs most frequently in the head and neck region. Diagnosis is based on typical histological presentation on hematoxylin and eosin (H and E stained slides together with the results of immunohistochemistry. Histologically, MCC has been classified into three distinct subtypes: Trabecular, intermediate and small cell type

  9. Environmentally friendly HF (DF) lasers

    Science.gov (United States)

    Apollonov, V. V.

    2016-08-01

    Dedicated to the 100th anniversary of the birth of Academician A M Prokhorov, this paper reviews the physics of self-sustained volume discharge without preionization—self-initiated volume discharge (SIVD)—in the working mixtures of non-chain hydrofluoride HF (deuterofluoride (DF)) lasers. The dynamics of SIVD in discharge gaps with different geometries is thoroughly described. The mechanisms for the restriction of current density in a diffuse channel in electric discharges in SF6 and SF6 based mixtures (which determines whether SIVD is possible) are proposed and analyzed using simple models. The most probable mechanisms are the electron impact dissociation of SF6 and other mixture components, electron-ion recombination and electron attachment to vibrationally excited SF6 molecules. Starting from a comparative analysis of the rate coefficients of these processes, it is shown that electron-ion recombination is capable of compensating for electron detachment from negative ions via electron impact. It is also established that SIVD is not only observed in SF6, but also in other strongly electronegative gases. The factors that determine the uniformity of the active medium in non-chain HF (DF) lasers are analyzed. Some special features of non-chain HF (DF) lasers with different apertures operating are carefully examined. Consideration is given to the problem of increasing the aperture and discharge volume of non-chain HF (DF) lasers. Based on our experimental results, the possibility of increasing the energy of such lasers to ~1 kJ and above is shown.

  10. Structural degradation of thin HfO2 film on Ge during the postdeposition annealing

    Science.gov (United States)

    Miyata, Noriyuki; Yasuda, Tetsuji; Abe, Yasuhiro

    2010-05-01

    Securing the thermal robustness of thin hafnium oxide (HfO2) film on the semiconductor surface is an important technical issue in the fabrication of the metal-oxide-semiconductor field-effect transistor devices, as the HfO2-based high-k gate stacks usually undergo high-temperature processes. In this study, the structural development of thin HfO2 film on a Ge surface during postdeposition annealing in an ultrahigh vacuum was examined to explore the origin for the initial degradation of thin HfO2 film. Void nucleation and subsequent two-dimensional void growth take place at 780-840 °C, while the chemical composition of the remaining Hf oxide is virtually stable. Both the void nucleation and growth processes show similar larger activation energy of about 10 eV. Based on the observed manner of void growth and the estimated activation energies, the authors propose that mass transport on the HfO2 surface is responsible for void nucleation in the HfO2 films on Ge. The authors also compare the present results with the previous studies on HfO2/Si structures, and suggest that similar surface process leads to the local Hf silicidation.

  11. [Pathophysiology and treatment of ARMD].

    Science.gov (United States)

    Musat, O; Ochinciuc, Uliana; Gutu, Tatiana; Cristescu, T R; Coman, Corina

    2012-01-01

    A review regarding the pathophysiology of AMD as shown in the literature Targets in AMD treatment include: 1. Protection against oxidative stress; 2. Prevention of the accumulation of lipofuscin; 3. Reduction or elimination of chronic inflammation; 4. Changes involving the participation of complement inflammatory phenomena; 5. Changes in the phenomena of chronic inflammation which do not involve the participation of complement (eg. Mitochondria and extracellular matrix). The Neovascularization process includes: 1. Production of angiogenic factor; 2. Release of angiogenic factor; 3. The binding of factors to extracellular receptors and activation of intracellular signaling; 4. Activation of endothelial cells with basement membrane degradation; 5. Endothelial cell proliferation; 6. Endothelial cell migration; 7. Remodeling of extracellular matrix; 8. Tube formation; 9. Vascular stabilization. Therapy inAMD, based on physiological characteristics of early and late stages, is possible nowadays. It is possible to apply a specific treatment for each stage of AMD, but effective treatment requires combinations of specific therapeutic remedies involving different pathophysiological pathways.

  12. Pathophysiology of cutaneous lupus erythematosus

    OpenAIRE

    Achtman, Jordan C; Werth, Victoria P.

    2015-01-01

    The pathophysiology of cutaneous lupus erythematosus (CLE) encompasses the complex interactions between genetics, the environment, and cells and their products. Recent data have provided enhanced understanding of these interactions and the mechanism by which they cause disease. A number of candidate genes have been identified which increase the risk of developing CLE. Ultraviolet radiation, the predominant environmental exposure associated with CLE, appears to initiate CLE lesion formation by...

  13. Effects of Hf Incorporation on Negative Bias-Illumination Stress Stability in Hf-In-Zn-O Thin-Film Transistors

    Science.gov (United States)

    Kim, Sangwook; Park, Jae Chul; Kim, Dae Hwan; Lee, Jang-Sik

    2013-04-01

    In this study, highly reliable amorphous oxide semiconductor-based thin-film transistors (TFTs) were developed. The Hf concentration was systematically changed in the Hf-incorporated In-Zn-O (HIZO) TFTs, and Hf played an important role in determining the negative bias-illumination instability. The process parameters were optimized in order to obtain HIZO TFTs with an excellent stability. HIZO can be processed on a 6-in. wafer at low temperatures and is almost transparent in the visible range. Thus this material is promising for use in current TFTs as well as future transparent electronic device components with good electrical performance and excellent stability.

  14. A thirty second isomer in Hf-171

    NARCIS (Netherlands)

    Campbell, P; Billowes, J; Cochrane, ECA; Cooke, JL; Cooper, TG; Dendooven, P; Evans, DE; Grant, IS; Griffith, JAR; Honkanen, A; Huhta, M; Oinonen, M; Pearson, MR; Penttila, H; Persson, B.L.; Richardson, DS; Tungate, G; Wheeler, PD; Zybert, L; Aysto, J

    1997-01-01

    An isomer has been detected in Hf-171 with a half-life of T-1/2 = 29.5(9) s. The state was populated in the Yb-170(alpha,3n)Hf-171m reaction at a beam energy of E-alpha = 50 MeV in an on-line ion guide isotope separator. The isomeric Hf-17lm(+) beam was extracted from the ion guide, mass-analysed an

  15. Electron Microprobe Analysis of Hf in Zircon: Suggestions for Improved Accuracy of a Difficult Measurement

    Science.gov (United States)

    Fournelle, J.; Hanchar, J. M.

    2013-12-01

    It is not commonly recognized as such, but the accurate measurement of Hf in zircon is not a trivial analytical issue. This is important to assess because Hf is often used as an internal standard for trace element analyses of zircon by LA-ICPMS. The issues pertaining to accuracy revolve around: (1) whether the Hf Ma or the La line is used; (2) what accelerating voltage is applied if Zr La is also measured, and (3) what standard for Hf is used. Weidenbach, et al.'s (2004) study of the 91500 zircon demonstrated the spread (in accuracy) of possible EPMA values for six EPMA labs, 2 of which used Hf Ma, 3 used Hf La, and one used Hf Lb, and standards ranged from HfO2, a ZrO2-HfO2 compound, Hf metal, and hafnon. Weidenbach, et al., used the ID-TIMS values as the correct value (0.695 wt.% Hf.), for which not one of the EPMA labs came close to that value (3 were low and 3 were high). Those data suggest: (1) that there is a systematic underestimation error of the 0.695 wt% Hf (ID-TIMS Hf) value if Hf Ma is used; most likely an issue with the matrix correction, as the analytical lines and absorption edges of Zr La, Si Ka and Hf Ma are rather tightly packed in the electromagnetic spectrum. Mass absorption coefficients are easily in error (e.g., Donovan's determination of the MAC of Hf by Si Ka of 5061 differs from the typically used Henke value of 5449 (Donovan et al, 2002); and (2) For utilization of the Hf La line, however, the second order Zr Ka line interferes with Hf La if the accelerating voltage is greater than 17.99 keV. If this higher keV is used and differential mode PHA is applied, only a portion of the interference is removed (e.g., removal of escape peaks), causing an overestimation of Hf content. Unfortunately, it is virtually impossible to apply an interference correction in this case, as it is impossible to locate Hf-free Zr probe standard. We have examined many of the combinations used by those six EPMA labs and concluded that the optimal EPMA is done with Hf

  16. Evolution of continental crust and mantle heterogeneity: Evidence from Hf isotopes

    Science.gov (United States)

    Jonathan, Patchett P.; Kouvo, O.; Hedge, C.E.; Tatsumoto, M.

    1982-01-01

    We present initial 176Hf/177 Hf ratios for many samples of continental crust 3.7-0.3 Gy old. Results are based chiefly on zircons (1% Hf) and whole rocks: zircons are shown to be reliable carriers of essentially the initial Hf itself when properly chosen on the basis of U-Pb studies. Pre-3.0 Gy gneisses were apparently derived from an unfractionated mantle, but both depleted and undepleted mantle are evident as magma sources from 2.9 Gy to present. This mantle was sampled mainly from major crustal growth episodes 2.8, 1.8 and 0.7 Gy ago, all of which show gross heterogeneity of 176Hf/177Hf in magma sources from ??Hf=0 to +14, or about 60% of the variability of the present mantle. The approximate ??Hf=2??Nd relationship in ancient and modern igneous rocks shows that 176Lu/177Hf fractionates in general twice as much as 147Sm/144Nd in mantle melting processes. This allows an estimation of the relative value of the unknown bulk solid/liquid distribution coefficient for Hf. DLu/DHf=??? 2.3 holds for most mantle source regions. For garnet to be an important residual mantle phase, it must hold Hf strongly in order to preserve Hf-Nd isotopic relationships. The ancient Hf initials are consistent with only a small proportion of recycled older cratons in new continental crust, and with quasi-continuous, episodic growth of the continental crust with time. However, recycling of crust less than 150 My old cannot realistically be detected using Hf initials. The mantle shows clearly the general positive ??Hf resulting from a residual geochemical state at least back to 2.9 Gy ago, and seems to have repeatedly possessed a similar degree of heterogeneity, rather than a continuously-developing depletion. This is consistent with a complex dynamic disequilibrium model for the creation, maintenance and destruction of heterogeneity in the mantle. ?? 1981 Springer-Verlag.

  17. The study of multilayers Fe/Hf and Ni/Hf by slow positron beam technique

    Science.gov (United States)

    Tashiro, Mutsumi; Nakajyo, Terunobu; Murashige, Yusuke; Koizumi, Tomoya; Kanazawa, Ikuzo; Komori, Fumio; Soe, We-Hyo; Yamamoto, Ryoichi; Ito, Yasuo

    1997-05-01

    The S-parameters versus the incident positron energy are measured in the Ni/Hf multilayer, thin Hf film, thin Fe film and the bilayer Fe/Hf. We have analyzed the change in vacancy-type defects in these multilayers and thin films with the deposition temperature in the MBE system.

  18. Molecular pathophysiology of cerebral edema.

    Science.gov (United States)

    Stokum, Jesse A; Gerzanich, Volodymyr; Simard, J Marc

    2016-03-01

    Advancements in molecular biology have led to a greater understanding of the individual proteins responsible for generating cerebral edema. In large part, the study of cerebral edema is the study of maladaptive ion transport. Following acute CNS injury, cells of the neurovascular unit, particularly brain endothelial cells and astrocytes, undergo a program of pre- and post-transcriptional changes in the activity of ion channels and transporters. These changes can result in maladaptive ion transport and the generation of abnormal osmotic forces that, ultimately, manifest as cerebral edema. This review discusses past models and current knowledge regarding the molecular and cellular pathophysiology of cerebral edema.

  19. Molecular pathophysiology of cerebral edema

    Science.gov (United States)

    Gerzanich, Volodymyr; Simard, J Marc

    2015-01-01

    Advancements in molecular biology have led to a greater understanding of the individual proteins responsible for generating cerebral edema. In large part, the study of cerebral edema is the study of maladaptive ion transport. Following acute CNS injury, cells of the neurovascular unit, particularly brain endothelial cells and astrocytes, undergo a program of pre- and post-transcriptional changes in the activity of ion channels and transporters. These changes can result in maladaptive ion transport and the generation of abnormal osmotic forces that, ultimately, manifest as cerebral edema. This review discusses past models and current knowledge regarding the molecular and cellular pathophysiology of cerebral edema. PMID:26661240

  20. Narcolepsy: Pathophysiology and Neuropsychological Changes

    Directory of Open Access Journals (Sweden)

    Angela Naumann

    2003-01-01

    Full Text Available Narcolepsy is now recognized as a distinctive disorder with specific pathophysiology and neurochemical abnormalities. Findings on the role of the neuropeptide hypocretin are opening new avenues of research and new strategies for therapy. Recently, neuropsychological and electrophysiological studies have provided evidence for reduced memory performance on standard memory tests in addition to subjective complaints of forgetfulness which may be related to changes in attentional processing. Further studies are, however, necessary to clarify the neuropsychological profile in narcolepsy. This review focuses on the recent advances in understanding narcolepsy.

  1. Pathophysiology of hemolytic transfusion reactions.

    Science.gov (United States)

    Davenport, Robertson D

    2005-07-01

    Hemolytic transfusion reactions (HTR) are systemic reactions provoked by immunologic red blood cell (RBC) incompatibility. Clinical and experimental observations of such reactions indicate that they proceed through phases of humoral immune reaction, activation of phagocytes, productions of cytokine mediators, and wide-ranging cellular responses. HTR have many features in common with the systemic inflammatory response syndrome (SIRS). Knowledge of the pathophysiologic mechanisms in HTR suggest that newer biological agents that target complement intermediates or proinflammatory cytokines may be effective agents in the treatment of severe HTRs.

  2. Pathophysiologic and therapeutic importance of tissue ACE : A consensus report

    NARCIS (Netherlands)

    Dzau, VJ; Bernstein, K; Celermajer, D; Cohen, J; Dahlof, B; Deanfield, J; Diez, J; Drexler, H; Ferrari, R; van Gilst, W; Hansson, L; Hornig, B; Husain, A; Johnston, C; Lazar, H; Lonn, E; Luscher, T; Mancini, J; Mimran, A; Pepine, C; Rabelink, T; Remme, W; Ruilope, L; Ruzicka, M; Schunkert, H; Swedberg, K; Unger, T; Vaughan, D; Weber, M

    2002-01-01

    Angiotensin-converting enzyme (ACE) activation and the de novo production of angiotensin II contribute to cardiovascular disease through direct pathological tissue effects, including vascular remodeling and inflammation, as well as indirect action on nitric oxide bioavailability and its consequences

  3. Quantitative Phase Imaging Techniques for the Study of Cell Pathophysiology: From Principles to Applications

    Directory of Open Access Journals (Sweden)

    Hyunjoo Park

    2013-03-01

    Full Text Available A cellular-level study of the pathophysiology is crucial for understanding the mechanisms behind human diseases. Recent advances in quantitative phase imaging (QPI techniques show promises for the cellular-level understanding of the pathophysiology of diseases. To provide important insight on how the QPI techniques potentially improve the study of cell pathophysiology, here we present the principles of QPI and highlight some of the recent applications of QPI ranging from cell homeostasis to infectious diseases and cancer.

  4. HF radiation emitted by chaotic leader processes

    Science.gov (United States)

    Mäkelä, J. S.; Edirisinghe, M.; Fernando, M.; Montaño, R.; Cooray, V.

    2007-04-01

    This paper presents direct measurements of narrowband 10 MHz HF radiation from so-called “chaotic leaders” associated with subsequent return strokes. Although the term is controversial and poorly defined, we find that more than 30% of subsequent strokes in close lightning flashes contain electric field characteristics that are best described as “chaotic”. In earlier studies, return strokes have consistently been observed to be the strongest sources of HF radiation, but the results for leader processes are less consistent. We also observe return strokes to be the main HF emitter, and the leaders before the first return stroke in a flash sequence also emit HF though somewhat less intensely. The leaders preceding subsequent strokes typically emit little or no HF radiation, whether they are dart or dart-stepped leaders. However, it was observed that the presence of a chaotic component increases the leader HF intensity dramatically Defining the HF intensity unequivocally can be problematic for processes like chaotic leaders which have a combination of continuous and impulsive phenomena. Two time-domain methods were used to measure the HF intensity, the peak energy and the RMS energy. In the frequency domain these correspond to the energy spectral density (ESD) and power spectral density (PSD), respectively. It was found that the methods are not necessarily compatible. Thus, it is suggested that to clarify future work, leader processes should be characterized by the PSD rather than the ESD.

  5. HfS, Hyperfine Structure Fitting Tool

    CERN Document Server

    Estalella, Robert

    2016-01-01

    HfS is a tool to fit the hyperfine structure of spectral lines, with multiple velocity components. The HfS_nh3 procedures included in HfS fit simultaneously the hyperfine structure of the NH$_3$ (J,K)= (1,1) and (2,2) transitions, and perform a standard analysis to derive $T_\\mathrm{ex}$, NH$_3$ column density, $T_\\mathrm{rot}$, and $T_\\mathrm{k}$. HfS uses a Monte Carlo approach for fitting the line parameters. Especial attention is paid to the derivation of the parameter uncertainties. HfS includes procedures that make use of parallel computing for fitting spectra from a data cube.

  6. Parkinson's disease : The syndrome, the pathogenesis and pathophysiology

    NARCIS (Netherlands)

    Bartels, Anna L.; Leenders, Klaus L.

    Parkinson's disease (PD) is characterised by a slowly expanding degeneration of neurons particularly in the mesencephalon. The causes are unknown although risk factors in the genetic and toxic domain are being discovered. An important pathophysiological feature in PD is the loss of part of the

  7. Pathophysiology of reversible sudden deafness--epidemiological study.

    Directory of Open Access Journals (Sweden)

    Ohsaki,Katsuichiro

    1983-04-01

    Full Text Available Many aspects of the etiology and pathophysiology of reversible sudden deafness remain obscure. In order to better understand the pathophysiology of reversible sudden deafness we compared the results of two therapies which have different mechanisms of action. The results of therapy with tranexamic acid alone in 49 cases (57 ears of sudden deafness were compared with the results of treatment with so-called antisludging agents in 65 cases (69 ears using the chi square contingency test. The same therapeutic effect was observed in both groups despite the different modes of chemical action of the two therapeutics. A series of processes involving an increase in permeability of vascular walls and related edema, and extravascular red cell oozing due to hypoxia or anoxia leading to tissue damage in the inner ear seem to be important factors in the etiology and pathophysiology of reversible sudden deafness.

  8. [Pathophysiology of hypertension : What are our current concepts?].

    Science.gov (United States)

    Jordan, J

    2015-03-01

    In the year 2015, many questions regarding the pathophysiology of essential arterial hypertension remain unresolved. Substantial scientific progress has been made in various medical areas aided by novel molecular"omics" techniques. The findings could then be implemented in diagnostic and therapeutic procedures. In the field of hypertension research such methods have been applied in very large cohorts but have contributed less to pathophysiological understanding and clinical management than expected. The findings on the pathophysiological importance of baroreflex mechanisms, natriuretic peptides and osmotically inactive sodium storage discussed in this article all have something in common: all are based on small, carefully conducted human physiological investigations and often challenge current textbook knowledge. Nevertheless, these findings have opened up new research fields and are likely to affect clinical care.

  9. Redox signaling in pathophysiology of hypertension.

    Science.gov (United States)

    Majzunova, Miroslava; Dovinova, Ima; Barancik, Miroslav; Chan, Julie Y H

    2013-09-18

    Reactive oxygen species (ROS) are products of normal cellular metabolism and derive from various sources in different cellular compartments. Oxidative stress resultant from imbalance between ROS generation and antioxidant defense mechanisms is important in pathogenesis of cardiovascular diseases, such as hypertension, heart failure, atherosclerosis, diabetes, and cardiac hypertrophy. In this review we focus on hypertension and address sources of cellular ROS generation, mechanisms involved in regulation of radical homeostasis, superoxide dismutase isoforms in pathophysiology of hypertension; as well as radical intracellular signaling and phosphorylation processes in proteins of the affected cardiovascular tissues. Finally, we discuss the transcriptional factors involved in redox-sensitive gene transcription and antioxidant response, as well as their roles in hypertension.

  10. Takotsubo cardiomyopathy: Pathophysiology,diagnosis and treatment

    Institute of Scientific and Technical Information of China (English)

    Kazuo; Komamura; Miho; Fukui; Toshihiro; Iwasaku; Shinichi; Hirotani; Tohru; Masuyama

    2014-01-01

    In 1990,takotsubo cardiomyopathy(TCM)was first discovered and reported by a Japanese cardiovascular specialist.Since then,this heart disease has gained worldwide acceptance as an independent disease entity.TCM is an important entity that differs from acute myocardial infarction.It occurs more often in postmenopausal elderly women,is characterized by a transient hypokinesis of the left ventricular(LV)apex,and is associated with emotional or physical stress.Wall motion abnormality of the LV apex is generally transient and resolves within a few days to several weeks.Its prognosis is generally good.However,there are some reports of serious TCM complications,including hypotension,heart failure,ventricular rupture,thrombosis involving the LV apex,and torsade de pointes.It has been suggested that coronary spasm,coronary microvascular dysfunction,catecholamine toxicity and myocarditis might contribute to the pathogenesis of TCM.However,its pathophysiology is not clearly understood.

  11. Understanding changes in cardiovascular pathophysiology.

    Science.gov (United States)

    Chummun, Harry

    Cardiovascular pathophysiological changes, such as hypertension and enlarged ventricles, reflect the altered functions of the heart and its circulation during ill-health. This article examines the normal and altered anatomy of the cardiac valves, the contractile elements and enzymes of the myocardium, the significance of the different factors associated with cardiac output, and the role of the autonomic nervous system in the heart beat. It also explores how certain diseases alter these functions and result in cardiac symptoms. Nurses can benefit from knowledge of these specific changes, for example, by being able to ask relevant questions in order to ascertain the nature of a patients condition, by being able to take an effective patient history and by being able to read diagnostic results, such as electrocardiograms and cardiac enzyme results. All this will help nurses to promote sound cardiac care based on a physiological rationale.

  12. Pathophysiological Study of Sensitive Skin.

    Science.gov (United States)

    Buhé, Virginie; Vié, Katell; Guéré, Christelle; Natalizio, Audrey; Lhéritier, Céline; Le Gall-Ianotto, Christelle; Huet, Flavien; Talagas, Matthieu; Lebonvallet, Nicolas; Marcorelles, Pascale; Carré, Jean-Luc; Misery, Laurent

    2016-03-01

    Sensitive skin is a clinical syndrome characterized by the occurrence of unpleasant sensations, such as pruritus, burning or pain, in response to various factors, including skincare products, water, cold, heat, or other physical and/or chemical factors. Although these symptoms suggest inflammation and the activation of peripheral innervation, the pathophysiogeny of sensitive skin remains unknown. We systematically analysed cutaneous biopsies from 50 healthy women with non-sensitive or sensitive skin and demonstrated that the intraepidermal nerve fibre density, especially that of peptidergic C-fibres, was lower in the sensitive skin group. These fibres are involved in pain, itching and temperature perception, and their degeneration may promote allodynia and similar symptoms. These results suggest that the pathophysiology of skin sensitivity resembles that of neuropathic pruritus within the context of small fibre neuropathy, and that environmental factors may alter skin innervation.

  13. Dystonia : emerging concepts in pathophysiology.

    Directory of Open Access Journals (Sweden)

    Madhusudanan M

    1999-10-01

    Full Text Available The essential pathophysiological feature of dystonia is co-contraction of antagonistic muscles. This may be due to derangement of the spinal cord or cortical mechanism. In the cord, there is disruption of the normal reciprocal inhibition of antagonists during agonist contraction. This decreased reciprocal inhibition is due to reduced presynaptic inhibition of muscle afferent input to the inhibitory interneuron. The reduced presynaptic inhibition may in turn be either due to defective suprasegmental control or to changes in the tonic afferent input to the interneuron from cutaneous and muscle afferents. Alternatively, genesis of dystonia may entirely be a cortical mechanism. Overactivity of the premotor cortices, which receive projections from basal ganglia via ventral thalamus, could result in dystonia by abnormal activation of cortical motor neurons. This may again be due to a dopaminergic dysfunction of basal ganglia.

  14. Pathophysiologic mechanisms of biomedical nanomaterials.

    Science.gov (United States)

    Wang, Liming; Chen, Chunying

    2016-05-15

    Nanomaterials (NMs) have been widespread used in biomedical fields, daily consuming, and even food industry. It is crucial to understand the safety and biomedical efficacy of NMs. In this review, we summarized the recent progress about the physiological and pathological effects of NMs from several levels: protein-nano interface, NM-subcellular structures, and cell-cell interaction. We focused on the detailed information of nano-bio interaction, especially about protein adsorption, intracellular trafficking, biological barriers, and signaling pathways as well as the associated mechanism mediated by nanomaterials. We also introduced related analytical methods that are meaningful and helpful for biomedical effect studies in the future. We believe that knowledge about pathophysiologic effects of NMs is not only significant for rational design of medical NMs but also helps predict their safety and further improve their applications in the future.

  15. Aspects of HF radio propagation

    Directory of Open Access Journals (Sweden)

    Stephane Saillant

    2009-06-01

    Full Text Available

    radio systems. From the point of view Working Group 2 of the COST 296 Action, interest lies with effects associated

    with propagation via the ionosphere of signals within the HF band. Several aspects are covered in this paper:

    a The directions of arrival and times of flight of signals received over a path oriented along the trough have

    been examined and several types of propagation effects identified. Of particular note, combining the HF observations

    with satellite measurements has identified the presence of irregularities within the floor of the trough that

    result in propagation displaced from the great circle direction. An understanding of the propagation effects that

    result in deviations of the signal path from the great circle direction are of particular relevance to the operation

    of HF radiolocation systems.

    b Inclusion of the results from the above mentioned measurements into a propagation model of the northerly

    ionosphere (i.e. those regions of the ionosphere located poleward of, and including, the mid-latitude trough

    and the use of this model to predict the coverage expected from transmitters where the signals impinge on the

    northerly ionosphere

  16. Renal sodium avidity in heart failure: from pathophysiology to treatment strategies.

    Science.gov (United States)

    Mullens, Wilfried; Verbrugge, Frederik Hendrik; Nijst, Petra; Tang, Wai Hong Wilson

    2017-02-23

    Increased neurohumoral stimulation resulting in excessive sodium avidity and extracellular volume overload are hallmark features of decompensated heart failure. Especially in case of concomitant renal dysfunction, the kidneys often fail to elicit effective natriuresis. While assessment of renal function is generally performed by measuring serum creatinine-a surrogate for glomerular filtration-, this only represents part of the nephron's function. Alterations in tubular sodium handling are at least equally important in the development of volume overload and congestion. Venous congestion and neurohumoral activation in advanced HF further promote renal sodium and water retention. Interestingly, early on, before clinical signs of heart failure are evident, intrinsic renal derangements already impair natriuresis. This clinical review discusses the importance of heart failure (HF) induced changes in different nephron segments. A better understanding of cardiorenal interactions which ultimately result in sodium avidity in HF might help to treat and prevent congestion in chronic and acute HF.

  17. Isolation and Characterization of a Virulent Bacteriophage φPA-HF17 of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Fang Han

    2014-09-01

    Full Text Available Pseudomonas aeruginosa, an important causative agent of nosocomial infection, is found throughout the hospital environment in moist reservoirs, and multidrug-resistant strains of P. aeruginosa have been increasingly reported worldwide. Bacteriophages are often considered potential therapeutic candidates in treating infectious diseases. In this study, a novel virulent bacteriophage φPA-HF17, specific infecting clinical isolates of P. aeruginosa, was isolated and characterized from environmental sewage. Transmission electron microscopy showed that phage φPA-HF17 had an icosahedral head with a very short tail, and exhibited characteristics typical of a podovirus. Restriction analysis indicated that phage φPA-HF17 was a double-stranded DNA virus, which might be digested by some restriction endonucleases. Phage φPA-HF17 was highly infectious with a rapid adsorption (>90% adsorbed in 4 min. In a one-step growth experiment, phage φPA-HF17 was shown having a latent period of 10 minute, with corresponding burst sizes of 200 PFU/cell. Furthermore, when φPA-HF17 alone was incubated at different pHs and different temperatures, the phage was stable over a wide pH range (4 to 10 and at extreme temperature (50°C. These results suggest that φPA-HF17 may be candidate therapeutic phage to control P. aeruginosa infection.

  18. In-situ atomic layer deposition growth of Hf-oxide

    Energy Technology Data Exchange (ETDEWEB)

    Karavaev, Konstantin

    2010-06-17

    We have grown HfO{sub 2} on Si(001) by atomic layer deposition (ALD) using HfCl{sub 4}, TEMAHf, TDMAHf and H{sub 2}O as precursors. The early stages of the ALD were investigated with high-resolution photoelectron spectroscopy and X-ray absorption spectroscopy. We observed the changes occurring in the Si 2p, O 1s, Hf 4f, Hf 4d, and Cl 2p (for HfCl{sub 4} experiment) core level lines after each ALD cycle up to the complete formation of two layers of HfO{sub 2}. The investigation was carried out in situ giving the possibility to determine the properties of the grown film after every ALD cycle or even after a half cycle. This work focused on the advantages in-situ approach in comparison with ex-situ experiments. The study provides to follow the evolution of the important properties of HfO{sub 2}: contamination level, density and stoichiometry, and influence of the experimental parameters to the interface layer formation during ALD. Our investigation shows that in-situ XPS approach for ALD gives much more information than ex-situ experiments. (orig.)

  19. Distribution of p-process 174Hf in early solar system materials and the origin of nucleosynthetic Hf and W isotope anomalies in Ca-Al rich inclusions

    Science.gov (United States)

    Peters, Stefan T. M.; Münker, Carsten; Pfeifer, Markus; Elfers, Bo-Magnus; Sprung, Peter

    2017-02-01

    heterogeneities between the first refractory condensates may have been eradicated partially during CAI formation, because W isotope anomalies in CAIs appear to decrease with increasing W concentrations as inferred from time-integrated 182W/184W. Importantly, the 176Lu-176Hf and 182Hf-182W chronometers are not significantly affected by nucleosynthetic heterogeneity of Hf isotopes in bulk meteorites, but may be affected in CAIs.

  20. HF Transverse Segmentation and Tagging Jet Capability

    CERN Document Server

    Doroshkevich, E A; Kuleshov, Sergey

    1998-01-01

    So called tagging jets and pile-up were simulated for the optimisation of the HF segmentation. The energy resolution, angular resolution and efficiency of jet reconstruction are defined for different calorimeter segmentation.

  1. Microhardness evaluation alloys Hf-Si-B; Avaliacao de microdureza de ligas Hf-Si-B

    Energy Technology Data Exchange (ETDEWEB)

    Gigolotti, Joao Carlos Janio; Costa, Eliane Fernandes Brasil [Centro Universitario de Volta Redonda (UNIFOA), Volta Redonda, RJ (Brazil); Nunes, Carlos Angelo; Rocha, Elisa Gombio; Coelho, Gilberto Carvalho, E-mail: carlosjanio@uol.com.br, E-mail: eliane-costabrasi@hotmail.com, E-mail: cnunes@demar.eel.usp.br, E-mail: elisarocha@alunos.eel.usp.br, E-mail: coelho@demar.eel.usp.br [Universidade de Sao Paulo (USP), Lorena, SP (Brazil)

    2014-08-15

    The technological advance has generated increasing demand for materials that can be used under high temperature, what includes intermetallic MR-Si-B (MR = refractory metal) alloys with multiphase structures, that can also be applied in oxide environments. Thus, this work had for objective the micro hardness study of the Hf-Si-B system alloys, heat treated at 1600 deg C, in the Hf rich region. Hf-Si-B alloys had been produced with blades of Hf (min. 99.8%), Si (min. 99.998%) and B (min. 99.5%), in the voltaic arc furnace and heat treated at 1600 deg C under argon atmosphere. The relationship of the phases had been previously identified by X-ray diffraction and contrast in backscattered electron imaging mode. The alloys had their hardness analyzed by method Vickers (micro hardness) with load of 0.05 kgf and 0.2 kgf and application time of 20 s. The results, obtained from the arithmetic mean of measurements for each alloy on the heterogeneous region, showed a mean hardness of 11.08 GPA, with small coefficient of variation of 3.8%. The borides HfB2 (19.34 GPa) e HfB - 11.76 GPa, showed the hardness higher than the silicides Hf2Si (8.57 GPa), Hf5Si3 (9.63 GPa), Hf3Si2 (11.66 GPa), Hf5Si4 (10.00 GPa), HfSi (10.02 GPa) e HfSi2 (8.61 GPa). (author)

  2. Wound pruritus: pathophysiology and management

    Directory of Open Access Journals (Sweden)

    Paul JC

    2015-08-01

    Full Text Available Julia C PaulSchool of Nursing, Oakland University, Rochester, MI, USAPurpose: The objective of this article is to review literature on wound pruritus, with a focus on summarizing pathophysiology and management.Method: Literature related to the physiology of itch was reviewed. PubMed, MEDLINE, the Cumulative Index to Nursing and Allied Health Literature (CINAHL, and Embase were searched for all research studies written in English which include “wound” (injury/burn and “pruritus” (itch in the title or abstract. Articles were accepted if they involved wounds or acute burns. Literature related to options for management of wound pruritus was reviewed.Results: While all types of wounds can be the source of associated pruritus, most studies have been done concerning pruritus associated with burns. There are treatment options for pruritus which can be considered for management of wound pruritus. Conclusion: Further research is indicated to gain insights into the problem of wound pruritus. As more is learned about the physiology of wound pruritus, more effective management strategies can be developed and employed.Keywords: wound, chronic itch, C-fibers, spinothalamic tract, positron emission tomography, pruritogens

  3. Obesity: pathophysiology and clinical management.

    Science.gov (United States)

    Gurevich-Panigrahi, Tatiana; Panigrahi, Soumya; Wiechec, Emilia; Los, Marek

    2009-01-01

    Obesity is an increasingly serious socioeconomic and clinical problem. Between (1/4)-(1/3) of population in the developed countries can be classified as obese. Four major etiological factors for development of obesity are genetic determinants, environmental factors, food intake and exercise. Obesity increases the risk of the development of various pathologic conditions including: insulin-resistant diabetes mellitus, cardiovascular disease, non-alcoholic fatty liver disease, endocrine problems, and certain forms of cancer. Thus, obesity is a negative determinant for longevity. In this review we provide broad overview of pathophysiology of obesity. We also discuss various available, and experimental therapeutic methods. We highlight functions of adipocytes including fat storing capacity and secretory activity resulting in numerous endocrine effects like leptin, IL-6, adiponectin, and resistin. The anti-obesity drugs are classified according to their primary action on energy balance. Major classes of these drugs are: appetite suppressants, inhibitors of fat absorption (i.e. orlistat), stimulators of thermogenesis and stimulators of fat mobilization. The appetite suppressants are further divided into noradrenergic agents, (i.e. phentermine, phendimetrazine, benzphetamine, diethylpropion), serotoninergic agents (i.e. dexfenfluramine), and mixed noradrenergic-serotoninergic agents (i.e. sibutramine). Thus, we highlight recent advances in the understanding of the central neural control of energy balance, current treatment strategies for obesity and the most promising targets for the development of novel anti-obesity drugs.

  4. Photodetachment of HF-in an Electric Field

    Institute of Scientific and Technical Information of China (English)

    WANG De-Hua

    2008-01-01

    @@ Photdetachment of a negative HF-ion in an electric field is studied by using the two-centre model and the closed orbit theory.An analytic formula is presented for the electron flux of HF- in the presence of an electric field.The results show that the oscillation in the electron flux distribution is caused by the rescattering effect of the molecular ion core and the interference betweed the two nuclei.In addition,the interference between the orbits passing through the given spatial point also plays an important role in the electron flux distribution.This study provides a new understanding of the photodetachment of polar molecules in the presence of external field.

  5. First-principles calculated spin-gapless semiconducting behavior in quaternary VCoHfGa and CrFeHfGa Heusler compounds

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiude; Wu, Xiaolin [Institute of Theoretical Physics, Zunyi Normal College, Zunyi 563002 (China); Wu, Bo, E-mail: fqwubo@zync.edu.cn [Institute of Theoretical Physics, Zunyi Normal College, Zunyi 563002 (China); School of Marine Science and Technology, Northwestern Polytechnical University, Xian 710072 (China); Feng, Yu [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Li, Ping [Institute for Clean Energy & Advanced Materials (ICAEM), Southwest University, Chongqing 400715 (China); Huang, Haishen [Institute of Theoretical Physics, Zunyi Normal College, Zunyi 563002 (China)

    2016-07-15

    Highlights: • Structural, electronic and magnetic properties of quaternary Heusler alloy [VCo,CrFe]HfGa were detected theoretically. • The quaternary Heusler alloy [VCo,CrFe]HfGa are (or are nearly) spin gapless semiconductors at the lowest energy state. • The ferromagnetic coupling plays an important role in magnetism. - Abstract: By using generalized gradient approximation (GGA) scheme within the density functional theory (DFT), the structural, electronic and magnetic properties of LiMgPdSn-type quaternary Heusler alloy CrFeHfGa and VCoHfGa were detected compressively. The results reveal that the two alloys are (or are nearly) potential spin gapless semiconductors with a magnetic moment of 3 μ{sub B} per primitive cell and the minority-spin gap of 0.8 eV and 0.6 eV at Fermi level (ε{sub F}) during the rate of lattice change of about −5%, respectively. We deduce that the ferromagnetic coupling among transitional metals plays an important role in magnetism of Heusler alloy [CrFe,VCo]HfGa.

  6. Importância do modelo animal para testar hipóteses sobre a fisiopatologia do binômio diabetes e incontinência urinária feminina = Importance of animal model to test hypotheses about the pathophysiology of the binomial diabetes and female urinary incontinence

    OpenAIRE

    Marini,Gabriela

    2011-01-01

    Objetivos: discutir a importância do estudo de modelos animais para testar hipóteses sobre os mecanismos de continência urinária e fisiopatologia do binômio diabetes incontinência urinária Fonte de Dados: foi realizada revisão de literatura no PubMed e SciELO. Os descritores utilizados foram diabetes, urinary incontinence, urethra, human e rats Síntese dos Dados: existe forte correlação entre a gênese da incontinência urinária e o diabetes mellitus. Devido à similaridade entre a distrib...

  7. Partition coefficients of Hf, Zr, and REE between phenocrysts and groundmasses

    Science.gov (United States)

    Fujimaki, H.; Tatsumoto, M.; Aoki, K.-I.

    1984-01-01

    Partition coefficients of Hf, Zr, and REE between olivine, orthopyroxene, clinopyroxene, plagioclase, garnet, amphibole, ilmenite, phlogopite, and liquid are presented. Samples consist of megacrysts in kimberlite, phenocrysts in alkaline basalts, tholeiitic basalts and andesitic to dacitic rocks, and synthetic garnet and clinopyroxene in Hawaiian tholeiites. The Hf-Lu and Zr-Lu elemental fractionations are as large as the Lu-Sm or Lu-Nd fractionation. The Hf and Zr partition coefficients between mafic phenocrysts and liquids are smaller than the Lu partition coefficients, but are similar to the Nd or Sm partition coefficients. The Hf and Zr partition coefficients between ilmenite, phlogopite, and liquid are larger than the Lu partition coefficients for these minerals and their corresponding liquids. The Hf-Zr elemental fractionation does not occur except for extreme fractionation involving Zr-minerals and extremely low fO2. These data have an important bearing on chronological and petrogenetic tracer studies involving the Lu-Hf isotopic system.

  8. Pathophysiology of constipation in the older adult

    Institute of Scientific and Technical Information of China (English)

    G Lindsay McCrea; Christine Miaskowski; Nancy A Stotts; Liz Macera; Madhulika G Varma

    2008-01-01

    This review provides information on the definition of constipation,normal continence and defecation and a description of the pathophysiologic mechanisms of constipation.In addition,changes in the anatomy and physiology of the lower gastrointestinal tract associated with aging that may contribute to constipation are described.MEDLINE (1966-2007) and CINAHL (1980-2007) were searched.The following MeSH terms were used:constipation/etiology OR constipation/physiology OR constipation/physiopathology) AND (age factors OR aged OR older OR 80 and over OR middle age).Constipation is not well defined in the literature.While self-reported constipation increases with age,findings from a limited number of clinical studies that utilized objective measures do not support this association.Dysmotility and pelvic floor dysfunction are important mechanisms associated with constipation.Changes in GI function associated with aging appear to be relatively subtle based on a limited amount of conflicting data.Additional research is warranted on the effects of aging on GI function,as well as on the timing of these changes.

  9. Adipose tissue remodeling in pathophysiology of obesity.

    Science.gov (United States)

    Lee, Mi-Jeong; Wu, Yuanyuan; Fried, Susan K

    2010-07-01

    Recent studies demonstrate that adipose tissue undergoes a continuous process of remodeling that is pathologically accelerated in the obese state. Contrary to earlier dogma, adipocytes die and are replaced by newly differentiated ones. This review will summarize recent advances of our knowledge of the mechanisms that regulate adipose tissue remodeling and highlight the influences of obesity, depot, and sex, as well as the relevance of rodent models to humans. A substantial literature now points to the importance of dynamic changes in adipocyte and immune cell turnover, angiogenesis, and extracellular matrix remodeling in regulating the expandability and functional integrity of this tissue. In obesity, the macrophages are recruited, surrounding dead adipocytes and polarized toward an inflammatory phenotype. The number of dead adipocytes is closely associated with the pathophysiological consequences of obesity, including insulin resistance and hepatic steatosis. Further, there are substantial depot, sex and species differences in the extent of remodeling. Adipose tissue undergoes a continuous remodeling process that normally maintains tissue health, but may spin out of control and lead to adipocyte death in association with the recruitment and activation of macrophages, and systemic insulin resistance.

  10. Hemorrhoids: From basic pathophysiology to clinical management

    Institute of Scientific and Technical Information of China (English)

    Varut Lohsiriwat

    2012-01-01

    This review discusses the pathophysiology,epidemiology,risk factors,classification,clinical evaluation,and current non-operative and operative treatment of hemorrhoids.Hemorrhoids are defined as the symptomatic enlargement and distal displacement of the normal anal cushions.The most common symptom of hemorrhoids is rectal bleeding associated with bowel movement.The abnormal dilatation and distortion of the vascular channel,together with destructive changes in the supporting connective tissue within the anal cushion,is a paramount finding of hemorrhoids.It appears that the dysregulation of the vascular tone and vascular hyperplasia might play an important role in hemorrhoidal development,and could be a potential target for medical treatment.In most instances,hemorrhoids are treated conservatively,using many methods such as lifestyle modification,fiber supplement,suppositorydelivered anti-inflammatory drugs,and administration of venotonic drugs.Non-operative approaches include sclerotherapy and,preferably,rubber band ligation.An operation is indicated when non-operative approaches have failed or complications have occurred.Several surgical approaches for treating hemorrhoids have been introduced including hemorrhoidectomy and stapled hemorrhoidopexy,but postoperative pain is invariable.Some of the surgical treatments potentially cause appreciable morbidity such as anal stricture and incontinence.The applications and outcomes of each treatment are thoroughly discussed.

  11. Catamenial epilepsy: definition, prevalence pathophysiology and treatment.

    Science.gov (United States)

    Herzog, Andrew G

    2008-03-01

    Seizures do not occur randomly. They tend to cluster in the majority of men and women with epilepsy. Seizure clusters, in turn, often show a periodicity. When the periodicity of seizure exacerbation aligns itself with that of the menstrual cycle, it is designated as catamenial epilepsy. The neuroactive properties of reproductive steroids and the cyclic variation in their serum concentrations are important pathophysiologic factors. Recent investigations have demonstrated and confirmed the existence of at least three patterns of catamenial seizure exacerbation: perimenstrual and periovulatory in ovulatory cycles and entire luteal phase in anovulatory cycles. A rational mathematical basis for the categorization of seizure exacerbation as catamenial epilepsy has been developed. It identifies approximately one third of women as having catamenial epilepsy. If seizures show hormonal sensitivity in their occurrence, they may also respond to hormonal treatment. Successful open label trials using cyclic natural progesterone supplement, depomedroxyprogesterone and gonadotropin-releasing hormone analogues in women and using testosterone with or without aromatase inhibitor in men have been reported. Prospective, randomized, placebo-controlled, double-blind investigations are warranted and under way.

  12. Pathophysiology of the antiphospholipid antibody syndrome.

    Science.gov (United States)

    Willis, Rohan; Pierangeli, Silvia S

    2011-11-01

    Antiphospholipid antibodies (aPL) are associated with the recurrent pregnancy loss and thrombosis that characterizes the antiphospholipid antibody syndrome (APS). Although the ontogeny of these pathogenic antibodies has not been fully elucidated, there is evidence that indicates the involvement of both genetic and environmental factors. The ability of aPL to induce a procoagulant phenotype in APS patients plays a central role in the development of arterial and venous thrombotic manifestations typical of the disease. Inflammation serves as a necessary link between this procoagulant phenotype and actual thrombus development and is an important mediator of the placental injury seen in APS patients with obstetric complications. Recent evidence has indicated a role for abnormal cellular proliferation and differentiation in the pathophysiology of APS, especially in those patients with pregnancy morbidity and other more atypical manifestations that have no identifiable thrombotic cause. The interplay of genetic and environmental factors responsible for aPL development and the mechanisms by which these antibodies produce disease in APS patients is the focus of this review.

  13. The chronobiology, etiology and pathophysiology of obesity.

    Science.gov (United States)

    Garaulet, M; Ordovás, J M; Madrid, J A

    2010-12-01

    The effect of CD on human health is an emerging issue. Many records link CD with diseases such as cancer, cardiovascular, cognitive impairment and obesity, all of them conducive to premature aging. The amount of sleep has declined by 1.5 h over the past century, accompanied by an important increase in obesity. Shift work, sleep deprivation and exposure to bright light at night increase the prevalence of adiposity. Animal models have shown that mice with Clock gene disruption are prone to developing obesity and MetS. This review summarizes the latest developments with regard to chronobiology and obesity, considering (1) how molecular clocks coordinate metabolism and the specific role of the adipocyte; (2) CD and its causes and pathological consequences; (3) the epidemiological evidence of obesity as a chronobiological illness; and (4) theories of circadian disruption and obesity. Energy intake and expenditure, relevance of sleep, fat intake from a circadian perspective and psychological and genetic aspects of obesity are examined. Finally, ideas about the use of chronobiology in the treatment of obesity are discussed. Such knowledge has the potential to become a valuable tool in the understanding of the relationship between the chronobiology, etiology and pathophysiology of obesity.

  14. Electronic and magnetic properties of 1T-HfS2 by doping transition-metal atoms

    Science.gov (United States)

    Zhao, Xu; Wang, Tianxing; Wang, Guangtao; Dai, Xianqi; Xia, Congxin; Yang, Lin

    2016-10-01

    We explored the electronic and magnetic properties of 1T-HfS2 doped by transition metal (TM) atom using the first-principles calculation. We doped the transition metal atoms from the IIIB to VIB groups in nonmagnetic 1T-HfS2. Numerical results show that the pristine 1T-HfS2 is a semiconductor with indirect gaps of 1.250 eV. Magnetism can be observed for V, Cr, Mn, Fe, Co, and Cu doping. The polarized charges mainly arise from the localized 3d electrons of the TM atom. The strong p-d hybridization was found between the 3d orbitals of TM and 3p orbitals of S. The substituted 1T-HfS2 can be a metal, semiconductor or half-metal. Analysis of the band structure and magnetic properties indicates that TM-doped HfS2 (TM = V, Fe, Cu) are promising systems to explore two-dimensional diluted magnetic semiconductors. The formation energy calculations also indicate that it is energetically favorable and relatively easier to incorporate transition metal atom into the HfS2 under S-rich experimental conditions. In contrast, V-doped HfS2 has relatively wide half-metallic gap and low formation energy. So V-doped 1T-HfS2 is ideal for spin injection, which is important for application in semiconductor spintronics.

  15. Pathophysiology of hypertension in obese children: a systematic review.

    Science.gov (United States)

    Wirix, A J G; Kaspers, P J; Nauta, J; Chinapaw, M J M; Kist-van Holthe, J E

    2015-10-01

    Hypertension is increasingly common in overweight and obese children. The mechanisms behind the development of hypertension in obesity are complex, and evidence is limited. In order to effectively treat obese children for hypertension, it is important to have a deeper understanding of the pathophysiology of hypertension in obese children. The present review summarizes the main factors associated with hypertension in obese children and discusses their potential role in its pathophysiology. Systematic searches were conducted in PubMed and EMBASE for articles published up to October 2014. In total, 60 relevant studies were included. The methodological quality of the included studies ranged from weak to strong. Several factors important in the development of hypertension in obese children have been suggested, including endocrine determinants, such as corticosteroids and adipokines, sympathetic nervous system activity, disturbed sodium homeostasis, as well as oxidative stress, inflammation and endothelial dysfunction. Understanding the pathophysiology of hypertension in overweight and obese children is important and could have implications for its screening and treatment. Based on solely cross-sectional observational studies, it is impossible to infer causality. Longitudinal studies of high methodological quality are needed to gain more insight into the complex mechanisms behind the development of hypertension in obese children.

  16. Kidney disease in heart failure: the importance of novel biomarkers for type 1 cardio-renal syndrome detection.

    Science.gov (United States)

    Palazzuoli, Alberto; McCullough, Peter A; Ronco, Claudio; Nuti, Ranuccio

    2015-08-01

    Chronic kidney disease (CKD) in heart failure (HF) has been recognized as an independent risk factor for adverse outcome, although the most important clinical trials tend to exclude patients with moderate and severe renal insufficiency. Despite this common association, the precise pathophysiological connection and liaison between heart and kidney is partially understood. Moreover, is it not enough considering how much cardio-renal syndrome type 1 is attributable to previous CKD, and how much to new-onset acute kidney injury (AKI). Neither development of AKI, its progression and time nor duration is related to an adverse outcome. An AKI definition is not universally recognized, and many confounding terms have been used in literature: "worsening renal function", "renal impairment", "renal dysfunction", etc., are all names that contribute to misunderstanding, and do not facilitate an universal classification. Therefore, AKI development should be the consequence of the basal clinical characteristics of patients, different primitive kidney disease and hemodynamic status. AKI could also be the mirror of several underlying associated diseases poorly controlled. Finally, it is not clear which is the optimal laboratory tool for identifying patients with an increased risk of AKI. In the current report, we review the different kidney diseases' impact in HF, and we analyze the modalities for AKI recognition during HF focusing our attention about some new biomarkers with potential application in the current setting.

  17. General concepts of modern HF communications

    Science.gov (United States)

    Aarons, Jules

    Both conceptual and hardware advancements have led to substantial systems developments in military HF communications; the former encompass coding and error correction techniques for security, in order to minimize propagation and interference, while the latter prominently include digital equipment permitting the selection of a frequency for a particular path and propagation mode, as well as modulation selection. Propagation-related advancements involve better statistical models as well as advancements in short-term forecasting methods responsive to changes in solar-geophysical parameters. Adaptive HF systems have been developed for meteor-scatter radio communications.

  18. Nightside studies of coherent HF Radar spectral width behaviour

    Directory of Open Access Journals (Sweden)

    E. E. Woodfield

    Full Text Available A previous case study found a relationship between high spectral width measured by the CUTLASS Finland HF radar and elevated electron temperatures observed by the EISCAT and ESR incoherent scatter radars in the post-midnight sector of magnetic local time. This paper expands that work by briefly re-examining that interval and looking in depth at two further case studies. In all three cases a region of high HF spectral width (>200 ms-1 exists poleward of a region of low HF spectral width (<200 ms-1. Each case, however, occurs under quite different geomagnetic conditions. The original case study occurred during an interval with no observed electrojet activity, the second study during a transition from quiet to active conditions with a clear band of ion frictional heating indicating the location of the flow reversal boundary, and the third during an isolated sub-storm. These case studies indicate that the relationship between elevated electron temperature and high HF radar spectral width appears on closed field lines after 03:00 magnetic local time (MLT on the nightside. It is not clear whether the same relationship would hold on open field lines, since our analysis of this relationship is restricted in latitude. We find two important properties of high spectral width data on the nightside. Firstly the high spectral width values occur on both open and closed field lines, and secondly that the power spectra which exhibit high widths are both single-peak and multiple-peak. In general the regions of high spectral width (>200 ms-1 have more multiple-peak spectra than the regions of low spectral widths whilst still maintaining a majority of single-peak spectra. We also find that the region of ion frictional heating is collocated with many multiple-peak HF spectra. Several mechanisms for the generation of high spectral width have been proposed which would produce multiple-peak spectra, these are discussed in relation to

  19. Um estudo teórico de propriedades moleculares em complexos de hidrogênio trimoleculares C2H4···2HF, C2H2···2HF e C3h6···2HF A theoretical study of molecular properties of C2H4···2HF, C2H2···2HF AND C3H6···2HF trimolecular hydrogen-bonded complexes

    Directory of Open Access Journals (Sweden)

    Boaz G. Oliveira

    2008-01-01

    Full Text Available We present a theoretical study of molecular properties in C2H4···2HF, C2H2···2HF and C3H6···2HF trimolecular hydrogen-bonded complexes. From B3LYP/6-311++G(d,p calculations, the most important structural deformations are related to the C=C (C2H4, C≡C (C2H2, C-C (C3H6 and HF bond lengths. According to the Bader's atoms in molecules and CHELPG calculations, it was identified a tertiary interaction between the fluorine atom of the second hydrofluoric acid molecule and hydrogen atoms of the ethylene and acetylene within the C2H4···2HF and C2H2···2HF complexes, respectively. Additionally, the evaluation of the infrared spectrum characterized the new vibrational modes and bathochromic effect of the HF molecules.

  20. Bipolar Resistive Switching Characteristics of HfO2/TiO2/HfO2 Trilayer-Structure RRAM Devices on Pt and TiN-Coated Substrates Fabricated by Atomic Layer Deposition

    Science.gov (United States)

    Zhang, Wei; Kong, Ji-Zhou; Cao, Zheng-Yi; Li, Ai-Dong; Wang, Lai-Guo; Zhu, Lin; Li, Xin; Cao, Yan-Qiang; Wu, Di

    2017-06-01

    The HfO2/TiO2/HfO2 trilayer-structure resistive random access memory (RRAM) devices have been fabricated on Pt- and TiN-coated Si substrates with Pt top electrodes by atomic layer deposition (ALD). The effect of the bottom electrodes of Pt and TiN on the resistive switching properties of trilayer-structure units has been investigated. Both Pt/HfO2/TiO2/HfO2/Pt and Pt/HfO2/TiO2/HfO2/TiN exhibit typical bipolar resistive switching behavior. The dominant conduction mechanisms in low and high resistance states (LRS and HRS) of both memory cells are Ohmic behavior and space-charge-limited current, respectively. It is found that the bottom electrodes of Pt and TiN have great influence on the electroforming polarity preference, ratio of high and low resistance, and dispersion of the operating voltages of trilayer-structure memory cells. Compared to using symmetric Pt top/bottom electrodes, the RRAM cells using asymmetric Pt top/TiN bottom electrodes show smaller negative forming voltage of -3.7 V, relatively narrow distribution of the set/reset voltages and lower ratio of high and low resistances of 102. The electrode-dependent electroforming polarity can be interpreted by considering electrodes' chemical activity with oxygen, the related reactions at anode, and the nonuniform distribution of oxygen vacancy concentration in trilayer-structure of HfO2/TiO2/HfO2 on Pt- and TiN-coated Si. Moreover, for Pt/HfO2/TiO2/HfO2/TiN devices, the TiN electrode as oxygen reservoir plays an important role in reducing forming voltage and improving uniformity of resistive switching parameters.

  1. Restless Legs Syndrome: From Pathophysiology to Clinical Diagnosis and Management

    Directory of Open Access Journals (Sweden)

    Shiyi Guo

    2017-06-01

    Full Text Available Restless legs syndrome (RLS, a common neurological sensorimotor disorder in western countries, has gained more and more attention in Asian countries. The prevalence of RLS is higher in older people and females. RLS is most commonly related to iron deficiency, pregnancy and uremia. The RLS symptoms show a significant circadian rhythm and a close relationship to periodic limb movements (PLMs in clinical observations, while the pathophysiological pathways are still unknown. The diagnostic criteria have been revised in 2012 to improve the validity of RLS diagnosis. Recent studies have suggested an important role of iron decrease of brain in RLS pathophysiology. Dopaminergic (DA system dysfunction in A11 cell groups has been recognized long ago from clinical treatment and autopsy. Nowadays, it is believed that iron dysfunction can affect DA system from different pathways and opioids have a protective effect on DA system. Several susceptible single nucleotide polymorphisms such as BTBD9 and MEIS1, which are thought to be involved in embryonic neuronal development, have been reported to be associated with RLS. Several pharmacological and non-pharmacological treatment are discussed in this review. First-line treatments of RLS include DA agents and α2δ agonists. Augmentation is very common in long-term treatment of RLS which makes prevention and management of augmentation very important for RLS patients. A combination of different types of medication is effective in preventing and treating augmentation. The knowledge on RLS is still limited, the pathophysiology and better management of RLS remain to be discovered.

  2. Restless Legs Syndrome: From Pathophysiology to Clinical Diagnosis and Management

    Science.gov (United States)

    Guo, Shiyi; Huang, Jinsha; Jiang, Haiyang; Han, Chao; Li, Jie; Xu, Xiaoyun; Zhang, Guoxin; Lin, Zhicheng; Xiong, Nian; Wang, Tao

    2017-01-01

    Restless legs syndrome (RLS), a common neurological sensorimotor disorder in western countries, has gained more and more attention in Asian countries. The prevalence of RLS is higher in older people and females. RLS is most commonly related to iron deficiency, pregnancy and uremia. The RLS symptoms show a significant circadian rhythm and a close relationship to periodic limb movements (PLMs) in clinical observations, while the pathophysiological pathways are still unknown. The diagnostic criteria have been revised in 2012 to improve the validity of RLS diagnosis. Recent studies have suggested an important role of iron decrease of brain in RLS pathophysiology. Dopaminergic (DA) system dysfunction in A11 cell groups has been recognized long ago from clinical treatment and autopsy. Nowadays, it is believed that iron dysfunction can affect DA system from different pathways and opioids have a protective effect on DA system. Several susceptible single nucleotide polymorphisms such as BTBD9 and MEIS1, which are thought to be involved in embryonic neuronal development, have been reported to be associated with RLS. Several pharmacological and non-pharmacological treatment are discussed in this review. First-line treatments of RLS include DA agents and α2δ agonists. Augmentation is very common in long-term treatment of RLS which makes prevention and management of augmentation very important for RLS patients. A combination of different types of medication is effective in preventing and treating augmentation. The knowledge on RLS is still limited, the pathophysiology and better management of RLS remain to be discovered. PMID:28626420

  3. Hypertrophic cardiomyopathy: Part 1 - Introduction, pathology and pathophysiology

    Directory of Open Access Journals (Sweden)

    Praveen Kerala Varma

    2014-01-01

    Full Text Available Hypertrophic cardiomyopathy (HCM is the most common genetic cardiovascular disease with many genotype and phenotype variations. Earlier terminologies, hypertrophic obstructive cardiomyopathy and idiopathic hypertrophic sub-aortic stenosis are no longer used to describe this entity. Patients present with or without left ventricular outflow tract (LVOT obstruction. Resting or provocative LVOT obstruction occurs in 70% of patients and is the most common cause of heart failure. The pathology and pathophysiology of HCM includes hypertrophy of the left ventricle with or without right ventricular hypertrophy, systolic anterior motion of mitral valve, dynamic and mechanical LVOT obstruction, mitral regurgitation, diastolic dysfunction, myocardial ischemia, and fibrosis. Thorough understanding of pathology and pathophysiology is important for anesthetic and surgical management.

  4. Obesity and cardiovascular disease: from pathophysiology to risk stratification.

    Science.gov (United States)

    Marinou, Kyriakoula; Tousoulis, Dimitris; Antonopoulos, Alexios S; Stefanadi, Elli; Stefanadis, Christodoulos

    2010-01-07

    Obesity is associated with numerous co-morbidities such as cardiovascular diseases (CVD), type 2 diabetes, hypertension and others. As obesity is considered to be a major risk factor for atherosclerosis, understanding of the underlying mechanisms leading to obesity and linking obesity with atherogenesis is necessary, for the development of therapeutic strategies against atherosclerosis. The pathophysiology of CVD linked to obesity is an area of intensive research. In this review we examine the role of obesity on CVD, and we focus on specific mechanisms of major importance in atherogenesis, such as the role of adipokines, insulin resistance, endothelial function and cardiac structure with emphasis on the effects of obesity on vascular endothelium and atherosclerosis. We then proceed from the pathophysiology of obesity to clinical practice, and we discuss clinical studies linking obesity with subclinical or overt CVD. We highlight that obesity is an easily assessed cardiovascular risk factor in the clinical setting and strategies to promote optimal body weight should be encouraged.

  5. [Structural and functional neuroimaging of the pathophysiology of apraxia].

    Science.gov (United States)

    Weiss, P H; Fink, G R

    2010-12-01

    A better understanding of the neural bases of apraxia is an important prerequisite to develop new therapeutic strategies for the disabling apraxic deficits after left-hemisphere stroke, like disturbed imitation of gestures, deficient pantomime, and object use deficits. Recently, functional and structural imaging methods allowed deeper insights into the pathophysiology of apraxia: While apraxic object use deficits result from the dysfunction of an extended fronto-parietal network within the left hemisphere, pantomime deficits are caused by impaired functioning of the left inferior frontal cortex. Further apraxia-related, motor cognitive processes (i.e., gesture imitation, integration of temporal and spatial movement information, and intentional movement planning) depend on the integrity of the left parietal cortex. Newly developed functional and structural imaging methods, like dynamic causal modelling (DCM) and diffusion tensor imaging (DTI), promise to further elucidate the pathophysiology of apraxia at the network level.

  6. Advances in treating amyotrophic lateral sclerosis: insights from pathophysiological studies.

    Science.gov (United States)

    Vucic, Steve; Rothstein, Jeffrey D; Kiernan, Matthew C

    2014-08-01

    Amyotrophic lateral sclerosis (ALS) is the most frequently occurring of the neuromuscular degenerative disorders, with a median survival time of 3-5 years. The pathophysiological mechanisms underlying ALS are multifactorial, with a complex interaction between genetic factors and molecular pathways. To date 16 genes and loci have been associated with ALS, with mutations in DNA/RNA-regulating genes including the recently described c9orf72 (chromosome 9 open reading frame 72) gene, suggesting an important role for dysregulation of RNA metabolism in ALS pathogenesis. Further, dysfunction of molecular pathways, including glutamate-mediated excitotoxicity, has been identified in sporadic and familial ALS, indicating the existence of a common pathogenic pathway. These pathophysiological insights have suggested novel therapeutic approaches, including stem cell and genetics-based strategies, providing hope for feasible treatment of ALS.

  7. Systematic Comparison of HF CMOS Transconductors

    NARCIS (Netherlands)

    Klumperink, Eric A.M.; Nauta, Bram

    2003-01-01

    Transconductors are commonly used as active elements in high-frequency (HF) filters, amplifiers, mixers, and oscillators. This paper reviews transconductor design by focusing on the V-I kernel that determines the key transconductor properties. Based on bandwidth considerations, simple V-I kernels wi

  8. Electron impact on vibrationally cold {{HF}}^{+}

    Science.gov (United States)

    Cristian Stroe, Marius; Fifirig, Magda

    2016-12-01

    The dissociative recombination and vibrational excitation processes induced by electron impact on vibrationally cold {{HF}}+ are investigated in the framework of the multichannel quantum defect theory for electron energies below 1 eV. The thermal rate coefficients for the electron temperature range from 10 to 5000 K are reported.

  9. ORIGIN OF EXCESS (176)Hf IN METEORITES

    DEFF Research Database (Denmark)

    Thrane, Kristine; Connelly, James Norman; Bizzarro, Martin

    2010-01-01

    After considerable controversy regarding the (176)Lu decay constant (lambda(176)Lu), there is now widespread agreement that (1.867 +/- 0.008) x 10(-11) yr(-1) as confirmed by various terrestrial objects and a 4557 Myr meteorite is correct. This leaves the (176)Hf excesses that are correlated with...

  10. Circulating levels of tumor necrosis factor-alpha receptor 2 are increased in heart failure with preserved ejection fraction relative to heart failure with reduced ejection fraction: evidence for a divergence in pathophysiology.

    Directory of Open Access Journals (Sweden)

    Brendan N Putko

    Full Text Available BACKGROUND: Various pathways have been implicated in the pathogenesis of heart failure (HF with preserved ejection fraction (HFPEF. Inflammation in response to comorbid conditions, such as hypertension and diabetes, may play a proportionally larger role in HFPEF as compared to HF with reduced ejection fraction (HFREF. METHODS AND RESULTS: This study investigated inflammation mediated by the tumor necrosis factor-alpha (TNFα axis in community-based cohorts of HFPEF patients (n = 100, HFREF patients (n = 100 and healthy controls (n = 50. Enzyme-linked immunosorbent assays were used to investigate levels of TNFα, its two receptors (TNFR1 and TNFR2, and a non-TNFα cytokine, interleukin-6 (IL-6, in plasma derived from peripheral blood samples. Plasma levels of TNFα and TNFR1 were significantly elevated in HFPEF relative to controls, while levels of TNFR2 were significantly higher in HFPEF than both controls and HFREF. TNFα, TNFR1 and TNFR2 were each significantly associated with at least two of the following: age, estimated glomerular filtration rate, hypertension, diabetes, smoking, peripheral vascular disease or history of atrial fibrillation. TNFR2 levels were also significantly associated with increasing grade of diastolic dysfunction and severity of symptoms in HFPEF. CONCLUSIONS: Inflammation mediated through TNFα and its receptors, TNFR1 and TNFR2, may represent an important component of a comorbidity-induced inflammatory response that partially drives the pathophysiology of HFPEF.

  11. Gastric asthma : a pathophysiological entity?

    NARCIS (Netherlands)

    Peters, FTM; Kleibeuker, JH; Postma, DS

    1998-01-01

    Background: Gastro-oesophageal reflux disease (GORD) is manifested by typical reflux symptoms and atypical extra-oesophageal symptoms. Important in this respect are respiratory conditions. Gastric asthma is a prominent example of these extra-oesophageal manifestations of GORD. There is, however, muc

  12. Electronic and magnetic properties of 1T-HfS{sub 2} by doping transition-metal atoms

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xu, E-mail: zhaoxu@htu.cn [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Wang, Tianxing; Wang, Guangtao [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Dai, Xianqi [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Department of Physics, Zhengzhou Normal University, Zhengzhou, Henan 450044 (China); Xia, Congxin [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Yang, Lin [School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007 (China)

    2016-10-15

    Highlights: • Pristine 1T-HfS{sub 2} is a semiconductor with indirect gaps of 1.250 eV • Magnetism can be observed for V, Cr, Mn, Fe, Co, and Cu doping. • Strong p–d hybridization was found between TM 3d orbitals and S 3p orbitals. • V-doped 1T-HfS{sub 2} is ideal for spin injection. - Abstract: We explored the electronic and magnetic properties of 1T-HfS{sub 2} doped by transition metal (TM) atom using the first-principles calculation. We doped the transition metal atoms from the IIIB to VIB groups in nonmagnetic 1T-HfS{sub 2}. Numerical results show that the pristine 1T-HfS{sub 2} is a semiconductor with indirect gaps of 1.250 eV. Magnetism can be observed for V, Cr, Mn, Fe, Co, and Cu doping. The polarized charges mainly arise from the localized 3d electrons of the TM atom. The strong p–d hybridization was found between the 3d orbitals of TM and 3p orbitals of S. The substituted 1T-HfS{sub 2} can be a metal, semiconductor or half-metal. Analysis of the band structure and magnetic properties indicates that TM-doped HfS{sub 2} (TM = V, Fe, Cu) are promising systems to explore two-dimensional diluted magnetic semiconductors. The formation energy calculations also indicate that it is energetically favorable and relatively easier to incorporate transition metal atom into the HfS{sub 2} under S-rich experimental conditions. In contrast, V-doped HfS{sub 2} has relatively wide half-metallic gap and low formation energy. So V-doped 1T-HfS{sub 2} is ideal for spin injection, which is important for application in semiconductor spintronics.

  13. Current concepts in the pathophysiology of glaucoma

    Directory of Open Access Journals (Sweden)

    Agarwal Renu

    2009-01-01

    Full Text Available Glaucoma, the second leading cause of blindness, is characterized by changes in the optic disc and visual field defects. The elevated intraocular pressure was considered the prime factor responsible for the glaucomatous optic neuropathy involving death of retinal ganglion cells and their axons. Extensive investigations into the pathophysiology of glaucoma now reveal the role of multiple factors in the development of retinal ganglion cell death. A better understanding of the pathophysiological mechanisms involved in the onset and progression of glaucomatous optic neuropathy is crucial in the development of better therapeutic options. This review is an effort to summarize the current concepts in the pathophysiology of glaucoma so that newer therapeutic targets can be recognized. The literature available in the National Medical Library and online Pubmed search engine was used for literature review.

  14. [Current insights into the pathophysiology of rosacea].

    Science.gov (United States)

    Schauber, J; Homey, B; Steinhoff, M

    2013-07-01

    Rosacea is a chronic inflammatory skin disease mainly affecting the face. Four major clinical subtypes of rosacea can be identified: erythemato-telangiectatic, papulopustular, phymatous and ocular rosacea. Still, it is currently unclear whether these subtypes develop consecutively or if any subtypes may occur individually as part of a syndrome. Rosacea is characterized by facial flushing, erythema, chronic inflammation, edema and fibrosis. Several trigger factors can worsen the disease or cause recurring episodes of inflammation. Although some aspects in the pathophysiology of rosacea have been characterized in more detail during the past years, the precise interplay of the various dysregulated systems is still poorly understood. In early disease manifestations and milder stages, dysfunction of neurovascular regulation and the innate immune system seem to be driving forces in rosacea pathophysiology. A disturbed chemokine and cytokine network further contributes to disease progression. This current review highlights some of the recent findings in rosacea pathophysiology and points out novel targets for therapeutic intervention.

  15. Wnt7b is an important intrinsic regulator of hair follicle stem cell homeostasis and hair follicle cycling.

    Science.gov (United States)

    Kandyba, Eve; Kobielak, Krzysztof

    2014-04-01

    The hair follicle (HF) is an exceptional mini-organ to study the mechanisms which regulate HF morphogenesis, cycling, hair follicle stem cell (hfSCs) homeostasis, and progeny differentiation. During morphogenesis, Wnt signaling is well-characterized in the initiation of HF patterning but less is known about which particular Wnt ligands are required and whether individual Wnt ligands act in an indispensable or redundant manner during postnatal hfSCs anagen onset and HF cycle progression. Previously, we described the function of the bone morphogenetic protein (BMP) signaling target gene WNT7a in intrinsic regulation of hfSCs homeostasis in vivo. Here, we investigated the role of Wnt7b, which was also intrinsically upregulated in hfSCs during physiological and precocious anagen after BMP inhibition in vivo. We demonstrated Wnt7b to be a direct target of canonical BMP signaling in hfSCs and using Wnt7b conditional gene targeting during HF morphogenesis revealed disrupted HF cycling including a shorter anagen, premature catagen onset with overall shorter hair production, and diminished HF differentiation marker expression. Additionally, we observed that postnatal ablation of Wnt7b resulted in delayed HF activation, affecting both the hair germ and bulge hfSCs but still maintaining a two-step sequence of HF stimulation. Interestingly, Wnt7b cKO hfSCs participated in reformation of the new HF bulge, but with slower self-renewal. These findings demonstrate the importance of intrinsic Wnt7b expression in hfSCs regulation and normal HF cycling and surprisingly reveal a nonredundant role for Wnt7b in the control of HF anagen length and catagen entry which was not compensated by other Wnt ligands.

  16. Environmental Regulation of Yersinia Pathophysiology.

    Science.gov (United States)

    Chen, Shiyun; Thompson, Karl M; Francis, Matthew S

    2016-01-01

    Hallmarks of Yersinia pathogenesis include the ability to form biofilms on surfaces, the ability to establish close contact with eukaryotic target cells and the ability to hijack eukaryotic cell signaling and take over control of strategic cellular processes. Many of these virulence traits are already well-described. However, of equal importance is knowledge of both confined and global regulatory networks that collaborate together to dictate spatial and temporal control of virulence gene expression. This review has the purpose to incorporate historical observations with new discoveries to provide molecular insight into how some of these regulatory mechanisms respond rapidly to environmental flux to govern tight control of virulence gene expression by pathogenic Yersinia.

  17. PULMONARY PATHOPHYSIOLOGY AND LUNG MECHANICS IN ANESTHESIOLOGY: A CASE-BASED OVERVIEW

    OpenAIRE

    2012-01-01

    The induction and maintenance of anesthesia, surgical requirements, and patients’ unique pathophysiology all combine to create a setting in which our accumulated knowledge of respiratory physiology and lung mechanics take on immediate and central importance in patient management. In this review we will take a case-based approach to illustrate how the complex interactions between anesthesia, surgery, and patient disease impact patient care with respect to pulmonary pathophysiology and clinical...

  18. CTO pathophysiology: how does this affect management?

    Science.gov (United States)

    Irving, John

    2014-05-01

    Chronic total occlusion (CTO) pathophysiology has been described in a few, small studies using post mortem histology, and more recently, in vivo intravascular ultrasound (IVUS) to analyse the constituents of occluded segments. Recent improvements in equipment and techniques have revealed new insights into physical characteristics of occluded coronaries, which in turn enable predictable procedural success. The purpose of this review is to consider the published evidence describing CTO pathophysiology from the perspective of the hybrid algorithm approach to CTO PCI. Literature searches using "Chronic Occlusion", "angioplasty", and" pathology" as keywords. Further searches on "coronary" "collateral", "Viability". Bibliographies were scrutinised for further key publications in an iterative process. Papers describing animal models were excluded.

  19. Curative effect of HF10 on liver and peritoneal metastasis mediated by host antitumor immunity

    Science.gov (United States)

    Hotta, Yoshihiro; Kasuya, Hideki; Bustos, Itzel; Naoe, Yoshinori; Ichinose, Toru; Tanaka, Maki; Kodera, Yasuhiro

    2017-01-01

    Background HF10 is a highly attenuated type 1 herpes simplex virus (HSV) with proven effective oncolytic effect. Previous investigations have demonstrated that colon cancer mice model treated with HF10 not only had better survival but were also resistant to the reimplantation of the antitumor effect mediated by host antitumor immunity. Importantly, it has also been noted that in mice with antitumors implanted on both sides of the back, an injection of HF10 on only one side strongly restrains not only the injected antitumor but also the non-injected ones. Materials and methods MC26 colon cancer cells were injected subcutaneously into the back, spleen, and intraperitoneal region of metastasis model mice. Antitumor volume and survival rate were monitored. To measure cytotoxic T lymphocytes (CTL) cytotoxicity against MC26, lymphocytes were extracted from the spleens of the peritoneal metastasis model mice as well as from the thymus of the liver metastasis model mice. The expression of interferon gamma was examined by enzyme-linked immunospot assay. Samples from the liver metastasis model mice were subjected to polymerase chain reaction to quantify the level of HSV genomes. Results HF10 was injected only on the back antitumor; however, a antitumor-suppressor effect was observed against liver and peritoneal metastases. When HF10 genome was measured, we observed lower genome on liver metastases compared to back antitumor genome quantity. CTL activity against MC26 was also observed. These results indicate that local administration of HF10 exerts a curative effect on systemic disease, mediated by host antitumor immunity. Conclusion HF10 local administration stimulates antitumor immunity to recognize antitumor-specific antigen, which then improves systemic disease. Metastatic antitumors lysis, on the other hand, appears to be mediated by the host immune system, rather than by virus-mediated direct oncolysis. PMID:28331843

  20. [Neural pathophysiology of cancer anorexia].

    Science.gov (United States)

    Sánchez-Lara, K; Sosa-Sánchez, R; Green-Renner, D; Méndez-Sánchez, N

    2011-01-01

    Approximately two thirds of cancer patients at advanced stages of the disease suffer from anorexia. Defined as the loss of the desire to eat, anorexia lower the energy intake which further exacerbates a progressive deterioration of the patient nutritional status. Malnutrition has a large impact on morbidity and mortality affecting the quality of life. Cancer anorexia etiology is multifactorial including complex interactions among the tumor, host metabolism and antineoplastic treatment. New related theories include peripheral and brain mechanisms affecting hypothalamic pathways; inducing behavioral and metabolic failure of responses to energy balance. The aim of this review is to describe actual concepts involved in the pathogenesis of cancer anorexia with special interest in brain mechanisms. Anorexia and reduced food intake are important issues in the management of cancer patients, more knowledge about pathogenic mechanism is needed to improve therapeutic options, prognosis and quality of life in cancer patients.

  1. The pathophysiology of pituitary adenomas.

    Science.gov (United States)

    Dworakowska, Dorota; Grossman, Ashley B

    2009-10-01

    The pathogenesis of tumour formation in the anterior pituitary has been intensively studied, but the causative mechanisms involved in pituitary cell transformation and tumourigenesis remain elusive. Most pituitary tumours are sporadic, but some arise as a component of genetic syndromes such as the McCune-Albright syndrome, multiple endocrine neoplasia type 1, Carney complex and, the most recently described, a MEN1-like phenotype (MEN4) and pituitary adenoma predisposition syndromes. Some specific genes have been identified that predispose to pituitary neoplasia (GNAS, MEN1, PRKAR1A, CDKN1B and AIP), but these are rarely involved in the pathogenesis of sporadic tumours. Mutations of tumour suppressor genes or oncogenes, as seen in more common cancers, do not seem to play an important role in the great majority of pituitary adenomas. The pituitary tumour transforming gene (PTTG; securin) was the first transforming gene found to be highly expressed in pituitary tumour cells, and seems to play an important role in the process of oncogenesis. Many tumour suppressor genes, especially those involved in the regulation of the cell cycle, are under-expressed, most often by epigenetic modulation - usually promoter hypermethylation - but the regulator of these co-ordinated series of methylations is also unclear. Cell signalling abnormalities have been identified in pituitary tumours, but their genetic basis is unknown. Both Raf/MEK/ERK and PI3K/Akt/mTOR pathways are over-expressed and/or over-activated in pituitary tumours: these pathways share a common root, including initial activation related to the tyrosine kinase receptor, and we speculate that a change to these receptors or their relationship to membrane matrix-related proteins may be an early event in pituitary tumourigenesis.

  2. Early Differentiation of the Crust-Mantle System: a Hf Isotope Perspective

    Science.gov (United States)

    Scherer, E.; Munker, C.; Mezger, K.

    2001-12-01

    epsilon Hf values. Either the volume of crust that was extracted in the Hadean was too small to cause moderate mantle depletion, or much of that early crust was recycled back into the mantle, thus effectively erasing evidence of early depletion. Importantly, the validity of these conclusions depends on the CHUR parameters (176Lu/177Hf, 176Hf/177Hf) that are used to calculate initial epsilon Hf values. References: E. Scherer, C. Munker, K. Mezger, Science 293, 683 (2001). J. Dalmasso, G. Barci-Funel, G.J. Ardisson, Appl. Radiat. Isotopes 43, 69 (1992). Y. Nir-El, N. Lavi, Appl. Radiat. Isotopes 49, 1653 (1998). M. Tatsumoto, D. M.. Unruh, P.J. Patchett, Mem. Natl. Inst. Polar Res., Special Issue no 20, Proceedings of the Sixth Symposium on Antarctic Meteorites, p. 237 (1981). A.P. Sguigna, A.J. Larabee, J.C. Waddington, Can. J. Phys. 60, 631 (1982). J.D. Vervoort, P.J. Patchett, G.E. Gehrels, A.P. Nutman, Nature 379, 624 (1996). J.D. Vervoort, J. Blichert-Toft, Gecohim. Cosmochim. Acta. 63, 533 (1999). Y. Amelin, D.-C. Lee, A.N. Halliday, R.T. Pidgeon, Nature 399, 252 (1999). Y. Amelin, D.-C. Lee, A.N. Halliday, Geochim Cosmochim Acta 64, 4205 (2000).

  3. Obesity cardiomyopathy: pathogenesis and pathophysiology.

    Science.gov (United States)

    Wong, Chiew; Marwick, Thomas H

    2007-08-01

    Obesity is becoming a worldwide phenomenon. Myocardial changes associated with the obese state are increasingly recognized, independent of hypertension, obstructive sleep apnea and coronary artery disease. The existence of a cardiomyopathy of obesity is supported by a range of evidence: epidemiologic study findings, which have shown an association between obesity and heart failure; clinical studies that have confirmed the association of adiposity with left ventricular dysfunction, independent of hypertension, coronary artery disease and other heart disease; and experimental evidence of structural and functional changes in the myocardium in response to increased adiposity. The most important mechanisms in the development of obesity cardiomyopathy are metabolic disturbances (insulin resistance, increased free fatty acid levels, and also increased levels of adipokines), activation of the renin-angiotensin-aldosterone and sympathetic nervous systems, myocardial remodeling, and small-vessel disease (both microangiopathy and endothelial dysfunction). In the first part of this two-part Review, we seek to evaluate the emerging evidence for the existence of a cardiomyopathy of obesity and clarify the responsible mechanisms.

  4. Pathophysiology of salt sensitivity hypertension.

    Science.gov (United States)

    Ando, Katsuyuki; Fujita, Toshiro

    2012-06-01

    Dietary salt intake is the most important factor contributing to hypertension, but the salt susceptibility of blood pressure (BP) is different in individual subjects. Although the pathogenesis of salt-sensitive hypertension is heterogeneous, it is mainly attributable to an impaired renal capacity to excrete sodium (Na(+) ). We recently identified two novel mechanisms that impair renal Na(+) -excreting function and result in an increase in BP. First, mineralocorticoid receptor (MR) activation in the kidney, which facilitates distal Na(+) reabsorption through epithelial Na(+) channel activation, causes salt-sensitive hypertension. This mechanism exists not only in models of high-aldosterone hypertension as seen in conditions of obesity or metabolic syndrome, but also in normal- or low-aldosterone type of salt-sensitive hypertension. In the latter, Rac1 activation by salt excess causes MR stimulation. Second, renospecific sympathoactivation may cause an increase in BP under conditions of salt excess. Renal beta2 adrenoceptor stimulation in the kidney leads to decreased transcription of the gene encoding WNK4, a negative regulator of Na(+) reabsorption through Na(+) -Cl (-) cotransporter in the distal convoluted tubules, resulting in salt-dependent hypertension. Abnormalities identified in these two pathways of Na(+) reabsorption in the distal nephron may present therapeutic targets for the treatment of salt-sensitive hypertension.

  5. Hyperprolactinemia: pathophysiology and therapeutic approach.

    Science.gov (United States)

    Capozzi, Anna; Scambia, Giovanni; Pontecorvi, Alfredo; Lello, Stefano

    2015-07-01

    Prolactin (PRL) is a hormone, mainly secreted by lactotroph cells of the anterior pituitary gland. Recent studies have shown it may also be produced by many extrapituitary cells. Its well-recognized PRL plays an important role in lactation during pregnancy, but it is involved in other biological functions such as angiogenesis, immunoregulation and osmoregulation. Hyperprolactinemia is a typical condition producing reproductive dysfunction in both sexes, resulting in hypogonadism, infertility and galactorrhea. It may be also asymptomatic. Lactotroph adenomas (prolactinoma) is one of the most common cause of PRL excess, representing approximately 40% of all pituitary tumors. Several other conditions should be excluded before a clear diagnosis of hyperprolactinemia is made. Hyperprolactinemia may be secondary to pharmacological or pathological interruption of hypothalamic-pituitary dopaminergic pathways or idiopathic. Stress, renal failure or hypothyroidism are other frequent conditions to exclude in patients with hyperprolactinemia. We will review biochemical characteristics and physiological functions of that hormone. Clinical and pharmacological approach to hyperprolactinemia will also be discussed.

  6. Joint Efforts Towards European HF Radar Integration

    Science.gov (United States)

    Rubio, A.; Mader, J.; Griffa, A.; Mantovani, C.; Corgnati, L.; Novellino, A.; Schulz-Stellenfleth, J.; Quentin, C.; Wyatt, L.; Ruiz, M. I.; Lorente, P.; Hartnett, M.; Gorringe, P.

    2016-12-01

    During the past two years, significant steps have been made in Europe for achieving the needed accessibility to High Frequency Radar (HFR) data for a pan-European use. Since 2015, EuroGOOS Ocean Observing Task Teams (TT), such as HFR TT, are operational networks of observing platforms. The main goal is on the harmonization of systems requirements, systems design, data quality, improvement and proof of the readiness and standardization of HFR data access and tools. Particular attention is being paid by HFR TT to converge from different projects and programs toward those common objectives. First, JERICO-NEXT (Joint European Research Infrastructure network for Coastal Observatory - Novel European eXpertise for coastal observaTories, H2020 2015 Programme) will contribute on describing the status of the European network, on seeking harmonization through exchange of best practices and standardization, on developing and giving access to quality control procedures and new products, and finally on demonstrating the use of such technology in the general scientific strategy focused by the Coastal Observatory. Then, EMODnet (European Marine Observation and Data Network) Physics started to assemble HF radar metadata and data products within Europe in a uniform way. This long term program is providing a combined array of services and functionalities to users for obtaining free of charge data, meta-data and data products on the physical conditions of European sea basins and oceans. Additionally, the Copernicus Marine Environment Monitoring Service (CMEMS) delivers from 2015 a core information service to any user related to 4 areas of benefits: Maritime Safety, Coastal and Marine Environment, Marine Resources, and Weather, Seasonal Forecasting and Climate activities. INCREASE (Innovation and Networking for the integration of Coastal Radars into EuropeAn marine SErvices - CMEMS Service Evolution 2016) will set the necessary developments towards the integration of existing European

  7. OSTEOARTHRITIS: A LOOK AT PATHOPHYSIOLOGY AND ...

    African Journals Online (AJOL)

    Correspondence to: Dr. G. O. Oyoo, Department of Clinical Medicine and Therapeutics, School of Medicine, ... Study design: Articles that emphasized the pathogenesis and pathophysiology and new treatment ..... Natural inhibitors capable of directly counteracting ... Etanercept for RA have been tried with little success.

  8. Physiological Coping: A Model for Teaching Pathophysiology

    Science.gov (United States)

    Porth, Carol M.

    1977-01-01

    The author discusses the use of a teaching model she developed for use in a pathophysiology. The model is based on the physiological component of C. Roy's adaptation model, which encourages students to look for physiological cues and apply relevant knowledge in patient care through a problem-solving approach. (TA)

  9. Retinal vein occlusion: pathophysiology and treatment options

    OpenAIRE

    Niral Karia

    2010-01-01

    Niral KariaDepartment of Ophthalmology, Southend Hospital, Prittlewell Chase, Westcliff on Sea, Essex, United KingdomAbstract: This paper reviews the current thinking about retinal vein occlusion. It gives an overview of its pathophysiology and discusses the evidence behind the various established and emerging treatment paradigms.Keywords: central, hemispheric, branch, retinal vein occlusion, visual loss

  10. Pathophysiology of valvular heart disease.

    Science.gov (United States)

    Zeng, Y I; Sun, Rongrong; Li, Xianchi; Liu, Min; Chen, Shuang; Zhang, Peiying

    2016-04-01

    Valvular heart disease (VHD) is caused by either damage or defect in one of the four heart valves, aortic, mitral, tricuspid or pulmonary. Defects in these valves can be congenital or acquired. Age, gender, tobacco use, hypercholesterolemia, hypertension, and type II diabetes contribute to the risk of disease. VHD is an escalating health issue with a prevalence of 2.5% in the United States alone. Considering the likely increase of the aging population worldwide, the incidence of acquired VHD is expected to increase. Technological advances are instrumental in identifying congenital heart defects in infants, thereby adding to the growing VHD population. Almost one-third of elderly individuals have echocardiographic or radiological evidence of calcific aortic valve (CAV) sclerosis, an early and subclinical form of CAV disease (CAVD). Of individuals ages >60, ~2% suffer from disease progression to its most severe form, calcific aortic stenosis. Surgical intervention is therefore required in these patients as no effective pharmacotherapies exist. Valvular calcium load and valve biomineralization are orchestrated by the concerted action of diverse cell-dependent mechanisms. Signaling pathways important in skeletal morphogenesis are also involved in the regulation of cardiac valve morphogenesis, CAVD and the pathobiology of cardiovascular calcification. CAVD usually occurs without any obvious symptoms in early stages over a long period of time and symptoms are identified at advanced stages of the disease, leading to a high rate of mortality. Aortic valve replacement is the only primary treatment of choice. Biomarkers such as asymmetric dimethylarginine, fetuin-A, calcium phosphate product, natriuretic peptides and osteopontin have been useful in improving outcomes among various disease states. This review, highlights the current understanding of the biology of VHD, with particular reference to molecular and cellular aspects of its regulation. Current clinical questions

  11. Digitally Driven Antenna for HF Transmission

    Science.gov (United States)

    2010-09-01

    the 1-MHz carrier signal. This signal is then fed into the base terminals of an NPN/ PNP transistor pair arranged in a push–pull configura- tion. A dual...negative voltage connected to the collector terminal of the PNP transistor . Since it was not possible to explicitly simulate the radia- tion of the time...complementary pair of switching transistors is driven with a pulsewidth modulated HF signal, eliminating the requirement for a frequency-dependent

  12. RFID UHF i HF w bibliotekach

    Directory of Open Access Journals (Sweden)

    Gładysz Bartłomiej

    2015-06-01

    Full Text Available The potential of the innovative Radio Frequency Identification (RFID technology to be applied for support, acceleration and automation of the circulation process of library collection is presented. Technology basics, and hardware and software components are described. Two different radio standards used in libraries are compared. The goal is to present the potential of RFID technology for libraries, to highlight the differences and to build a basis for further consideration of UHF and HF alternatives.

  13. Elastic and vibrational properties of monoclinic HfO2 from first-principles study

    Science.gov (United States)

    Wu, Rui; Zhou, Bo; Li, Qian; Jiang, ZhenYi; Wang, WenBo; Ma, WenYan; Zhang, XiaoDong

    2012-03-01

    The elastic and vibrational properties of crystalline monoclinic HfO2 have been investigated using density functional perturbation theory. Using the Voigt and Reuss theory, we estimate the bulk, shear and Young's modulus for polycrystalline HfO2, which agree very well with the available experimental and theoretical data. Additionally, we present a systematic analysis of the elastic properties of HfO2 polymorphs and find the trends in the elastic parameters for the HfO2 structures are consistent with those for the ZrO2 structures. The choice of exchange-correlation functional has an important effect on the results of elastic and vibrational properties. The utilization of Hartwigzen-Goedecker-Hutter type functional is a great improvement on calculation of the zone-centre phonon frequencies, and shows the root-mean-square absolute deviation of 7 cm-1 with experiments. A rigorous assignment of all the Raman modes is achieved by combining symmetry analysis with the first-principles calculations, which helps us to identify the main peak and some other features of Raman spectra. Furthermore, the Raman spectrum of HfO2 powder has been simulated for the first time, providing a theoretical benchmark for the interpretation of the unresolved problems in experimental studies.

  14. High-power ELF radiation generated by modulated HF heating of the ionosphere can cause Earthquakes, Cyclones and localized heating

    OpenAIRE

    De Aquino, Fran

    2011-01-01

    The High Frequency Active Auroral Research Program (HAARP) is currently the most important facility used to generate extremely low frequency (ELF) electromagnetic radiation in the ionosphere. In order to produce this ELF radiation the HAARP transmitter radiates a strong beam of high-frequency (HF) waves modulated at ELF. This HF heating modulates the electrons' temperature in the D region ionosphere and leads to modulated conductivity and a time-varying current which then radiates at the modu...

  15. High-power ELF radiation generated by modulated HF heating of the ionosphere can cause Earthquakes, Cyclones and localized heating

    OpenAIRE

    De Aquino, Fran

    2011-01-01

    The High Frequency Active Auroral Research Program (HAARP) is currently the most important facility used to generate extremely low frequency (ELF) electromagnetic radiation in the ionosphere. In order to produce this ELF radiation the HAARP transmitter radiates a strong beam of high-frequency (HF) waves modulated at ELF. This HF heating modulates the electrons' temperature in the D region ionosphere and leads to modulated conductivity and a time-varying current which then radiates at the modu...

  16. Current concepts in the pathophysiology of fibromyalgia: the potential role of oxidative stress and nitric oxide.

    Science.gov (United States)

    Ozgocmen, Salih; Ozyurt, Huseyin; Sogut, Sadik; Akyol, Omer

    2006-05-01

    Fibromyalgia (FM) is a common chronic pain syndrome with an unknown etiology. Recent years added new information to our understanding of FM pathophysiology. Researches on genetics, biogenic amines, neurotransmitters, hypothalamic-pituitary-adrenal axis hormones, oxidative stress, and mechanisms of pain modulation, central sensitization, and autonomic functions in FM revealed various abnormalities indicating that multiple factors and mechanisms are involved in the pathogenesis of FM. Oxidative stress and nitric oxide may play an important role in FM pathophysiology, however it is still not clear whether oxidative stress abnormalities documented in FM are the cause or the effect. This should encourage further researches evaluating the potential role of oxidative stress and nitric oxide in the pathophysiology of FM and the efficacy of antioxidant treatments (omega-3 and -6 fatty acids, vitamins and others) in double blind and placebo controlled trials. These future researches will enhance our understanding of the complex pathophysiology of this disorder.

  17. Usefulness of Iron Deficiency Correction in Management of Patients With Heart Failure [from the Registry Analysis of Iron Deficiency-Heart Failure (RAID-HF) Registry].

    Science.gov (United States)

    Wienbergen, Harm; Pfister, Otmar; Hochadel, Matthias; Michel, Stephan; Bruder, Oliver; Remppis, Björn Andrew; Maeder, Micha Tobias; Strasser, Ruth; von Scheidt, Wolfgang; Pauschinger, Matthias; Senges, Jochen; Hambrecht, Rainer

    2016-12-15

    Iron deficiency (ID) has been identified as an important co-morbidity in patients with heart failure (HF). Intravenous iron therapy reduced symptoms and rehospitalizations of iron-deficient patients with HF in randomized trials. The present multicenter study investigated the "real-world" management of iron status in patients with HF. Consecutive patients with HF and ejection fraction ≤40% were recruited and analyzed from December 2010 to October 2015 by 11 centers in Germany and Switzerland. Of 1,484 patients with HF, iron status was determined in only 923 patients (62.2%), despite participation of the centers in a registry focusing on ID and despite guideline recommendation to determine iron status. In patients with determined iron status, a prevalence of 54.7% (505 patients) for ID was observed. Iron therapy was performed in only 8.5% of the iron-deficient patients with HF; 2.6% were treated with intravenous iron therapy. The patients with iron therapy were characterized by a high rate of symptomatic HF and anemia. In conclusion, despite strong evidence of beneficial effects of iron therapy on symptoms and rehospitalizations, diagnostic and therapeutic efforts on ID in HF are low in the actual clinical practice, and the awareness to diagnose and treat ID in HF should be strongly enforced.

  18. Far-Field Testing Method of Spurious Emission Produced by HF RFID

    Directory of Open Access Journals (Sweden)

    Nikola Gvozdenovic

    2016-01-01

    Full Text Available We present measurements of spurious emission produced by high-frequency radio frequency identification (HF RFID using carrier frequency of 13.56 MHz. HF RFID tags produce unwanted emission due to rectification and more generally due to nonlinearity of analog front end. Depending on the conducting material of an HF RFID coil and surrounding dielectric material, the coil behaves as more or less good antenna on some harmonic frequencies. Exact characterization and analysis of unwanted emission is important from the security perspective as well as from the perspective of interference with other systems. Consequently we measured the harmonics produced in the integrated circuitry and characterized radiation properties of the antenna. Finally we present the measurements of the spurious emission performed in a Gigahertz Transverse Electromagnetic (GTEM cell.

  19. Troponin I in acute decompensated heart failure : insights from the ASCEND-HF study

    NARCIS (Netherlands)

    Felker, G. Michael; Hasselblad, Vic; Tang, W. H. Wilson; Hernandez, Adrian F.; Armstrong, Paul W.; Fonarow, Gregg C.; Voors, Adriaan A.; Metra, Marco; McMurray, John J. V.; Butler, Javed; Heizer, Gretchen M.; Dickstein, Kenneth; Massie, Barry M.; Atar, Dan; Troughton, Richard W.; Anker, Stefan D.; Califf, Robert M.; Starling, Randall C.; O'Connor, Christopher M.

    2012-01-01

    We examined the prognostic importance of cardiac troponin I (cTnI) in a cohort of patients enrolled in the ASCEND-HF study of nesiritide in acute decompensated heart failure (ADHF). Circulating troponins are a prognostic marker in patients with ADHF. Contemporary assays with greater sensitivity requ

  20. Predictors of arrhythmic sudden cardiac death in heart failure patients in the CARE-HF study

    DEFF Research Database (Denmark)

    Uretsky, B.; Cleland, J.G.F.; Freemantle, N.

    2006-01-01

    Topic(s):Rsynchronisation therapy   Cardiac resynchronization therapy (CRT) has become an important modality to improve symptoms, exercise performance, and survival in patients with severe heart failure and left ventricular dyssynchrony. The CARE-HF study showed that CRT reduced mortality in syst...

  1. Phase1 upgrade of the CMS-HF Calorimeter

    CERN Document Server

    Gulmez, Erhan

    2016-01-01

    In this presentation, results of the Phase I upgrade of the CMS Hadron Forward Calorimeter (HF) are discussed. The CMS-HF Calorimeter was using regular PMTs. Cherenkov light produced in the quartz fibers embedded in the iron absorber was read out with the PMTs. However, occasionally, stray muons hitting the PMT windows cause Cherenkov radiation in the PMT itself and produce large signals. These large signals mimic a very high-energy particle and are tagged as important by the trigger. To reduce this problem, PMTs had to be replaced. The four-anode PMTs that were chosen have thinner windows; thereby reducing the Cherenkov radiation in the PMT window. As part of the upgrade, the read-out electronics is to be replaced so that the PMTs are read out in two channels by connecting each pair of anodes to a single channel. Information provided by these two channels will help us reject the false signals due to the stray muons since the Cherenkov radiation in the PMT window is more likely to produce a signal only in one...

  2. Pathophysiological aspects of ureterorenoscopic management of upper urinary tract calculi

    DEFF Research Database (Denmark)

    Osther, Palle J S; Pedersen, Katja V; Lildal, Søren K;

    2016-01-01

    PURPOSE OF REVIEW: Indications for ureterorenoscopy are expanding without hard scientific evidence to support its efficacy. Therefore, it is extremely important to focus on potential harmful effects of the procedure itself. This review explores how physiology of the upper urinary tract reacts...... of the β-receptor agonist isoproterenol in the irrigation fluid has shown a potential for reducing both intrarenal pressure and ureteral tone during ureterorenoscopy. SUMMARY: Upper urinary tract physiology has unique features that may be pushed into pathophysiological processes by the unique elements...

  3. [Pathophysiology of Ataxia in Fisher Syndrome].

    Science.gov (United States)

    Kuwabara, Satoshi

    2016-12-01

    Fisher syndrome is regarded as a peculiar inflammatory neuropathy associated with ophthalmoplegia, ataxia, and areflexia. The disorder is associated with preceding infection, cerebrospinal fluid albumino-cytological dissociation, and spontaneous recovery, and regarded as a variant of Guillain-Barré syndrome. The discovery of anti-GQ1b IgG antibodies led to dramatic advances in understanding the pathophysiology of Fisher syndrome. The lesions in Fisher syndrome are determined by expression of ganglioside GQ1b in the human nervous system. This review article focuses on the pathophysiology of ataxia in Fisher syndrome. Current evidence suggests that antibody attack on Group Ia neurons in the dorsal root ganglia is mainly responsible for the sensory ataxia. Involvement of the muscle spindles might also contribute to the development of ataxia.

  4. [The pathophysiology of irritable bowel syndrome].

    Science.gov (United States)

    Zouiten, Mekki Lilia; Karoui, Sami; Boubaker, Jalel; Fekih, Monia; Mechmeche, Rachid; Filali, Azza

    2006-05-01

    The irritable bowel syndrome (IBS) is a frequent gastrointestinal disorder (10 -15% of the population). It is characterized by chronic abdominal pain with modification in the bowel habits. The diagnosis is based of ROME II criteria. The pathophysiology of the SII remains unknown . It result from visceral hypersensitivity with anomalies of the digestive motility. These anomalies are secondary of dysfunction of the brain - gut axis modulated by environmental and the psychosocial factors. The understanding of the pathophysiological mechanisms of the SII and in particular the function of the brain-gut axis will permit a better handling of the patients. Indeed, the present knowledge of the neurotransmitter implied in the communication between the central nervous system and the digestive tract are currently the basis of the new therapies aimed to modulate the mechanisms implicated in the causation of the several symptoms of IBS. These novel pharmacotherapy should reduce the indirect societal and costs of IBS.

  5. [Genomic approach to pathophysiology of rheumatoid arthritis].

    Science.gov (United States)

    Yamada, Ryo

    2012-11-01

    Genetic studies identified multiple genes and polymorphisms that increase risk to develop rheumatoid arthritis. Genomic approach is characterized with its integrative style using mathematical and statistical models. Its main targets include (1)combinatorial effect of multiple genetic and environmental factors, (2)heterogeneity of pathological states and its individuality, and (3)their chronological heterogeneity. Genomic approach will clarify pathophysiology of various diseases along with the progresses in molecular biology and other researches on individual molecules.

  6. Pathophysiology of Non Alcoholic Fatty Liver Disease

    Science.gov (United States)

    Petta, Salvatore; Gastaldelli, Amalia; Rebelos, Eleni; Bugianesi, Elisabetta; Messa, Piergiorgio; Miele, Luca; Svegliati-Baroni, Gianluca; Valenti, Luca; Bonino, Ferruccio

    2016-01-01

    The physiopathology of fatty liver and metabolic syndrome are influenced by diet, life style and inflammation, which have a major impact on the severity of the clinicopathologic outcome of non-alcoholic fatty liver disease. A short comprehensive review is provided on current knowledge of the pathophysiological interplay among major circulating effectors/mediators of fatty liver, such as circulating lipids, mediators released by adipose, muscle and liver tissues and pancreatic and gut hormones in relation to diet, exercise and inflammation. PMID:27973438

  7. Improvements on Signal Processing for HF Radar

    Institute of Scientific and Technical Information of China (English)

    LIU Yongtan; SHEN Yiying

    2001-01-01

    In this paper improvements on signalprocessing are achieved to enhance the performancesof H-F radar system, being unobtainable by the con-ventional signal processing. Using the improved sig-nal processing both high range resolution and longcoherent integration time may be obtained for goodbenefit to the target resolution and weak signal de-tection. Modification to the unmatched correspon-dence between range delay samples and range resolu-tion ceils saves an additional accumulation loss in therange processing. Finally, comparisons between theimproved and the conventional signal processing aregiven by numerical simulation.

  8. The importance of assessing nutritional status in elderly patients with heart failure.

    Science.gov (United States)

    Sargento, Luis; Longo, Susana; Lousada, Nuno; dos Reis, Roberto Palma

    2014-06-01

    Heart failure (HF) is a syndrome characterized by high morbidity and mortality, despite advances in medical and device therapy that have significantly improved survival. The outcome of HF in elderly patients results from a combination of biological, functional, psychological, and environmental factors, one of which is nutritional status. Malnutrition, as well as HF, is frequently present with aging. Early detection might lead to earlier intervention. It is our goal to review the importance of nutritional status in elderly patients with HF, as well as tools for assessing it. We also propose a simple decision algorithm for the nutritional assessment of elderly patients with HF.

  9. Systematic Study on Triaxial Superdeformed Bands of Hf Isotopes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Da-Li; DING Bin-Gang

    2009-01-01

    Properties of the triaxial superdeformed (TSD) bands of Hf isotopes are investigated systematically within the supersymmetry scheme including many-body interactions and a perturbation possessing the SO(5) (or SU(5)) symmetry on the rotational symmetry. Quantitatively good results of the γ-ray energies, the dynamical moments of inertia,and the spin of the TSD bands in Hf isotopes are obtained. It shows that this approach is quite powerful in describing the properties of the triaxial superdeformation in Hf isotopes.

  10. Determining Energy Distributions of HF-Accelerated Electrons at HAARP

    Science.gov (United States)

    2015-11-18

    AFRL-AFOSR-VA-TR-2015-0383 Determining energy distributions of HF-accelerated electrons at HAARP Christopher Fallen University of Alaska Fairbanks...2012 - 11/14/2015 4. TITLE AND SUBTITLE Determining energy distributions of HF-accelerated electrons at HAARP 5a. CONTRACT NUMBER FA9550-12-1-0424...transmitted from the High-frequency Active Auroral Research Program ( HAARP ) transmitter in Alaska. For a given fixed HF-plasma interaction altitude

  11. Physics of the Geospace Response to Powerful HF Radio Waves

    Science.gov (United States)

    2012-10-31

    studies of the response of the Earth’s space plasma to high-power HF radio waves from the High-frequency Active Auroral Research Program ( HAARP ...of HF heating and explored to simulate artificial ducts. DMSP- HAARP experiments revealed that HF-created ion outflows and artificial density ducts...in the topside ionosphere appeared faster than predicted by the models, pointing to kinetic (suprathermal) effects. CHAMP/GRACE- HAARP experiments

  12. [Functional imaging insights into the pathophysiology of apraxia].

    Science.gov (United States)

    Weiss-Blankenhorn, P H; Fink, G R

    2008-07-01

    Apraxias are disorders of motor cognition that cannot be explained by basic sensorimotor deficits or aphasia. The relatively high frequency of apraxia (approximately half of all patients with left-hemispheric stroke suffer from apraxia during the acute phase) as well as its prognostic value for determining the outcome of rehabilitative therapy clearly convey the necessity of more comprehensive research into the pathophysiology of apraxia in order to develop new therapeutic strategies. In recent years, functional imaging (PET and fMRI) has helped to provide important new insights into the pathophysiology of ideomotor apraxia (defective movement plan) and ideational apraxia (defective action concept). In this review, the neural bases for the clinically observed dissociations between the imitation of abstract and symbolic movements (as in ideomotor apraxia) and for the object-trigger system (which is disturbed in ideational apraxia) will be exemplified. Furthermore, we will recapitulate recent studies that provide evidence for the complementary functions of the right and left parietal cortices in the spatial and temporal organization of complex, object-related actions. The particular importance of the left parietal cortex for motor cognition is further supported by studies examining the integration of spatial and temporal movement information during the generation of a movement plan as well as by the generation of such movement plans in the left parietal cortex independent from the hand that executes the movement.

  13. Etiology, pathophysiology and conservative management of degenerative joint disease

    Directory of Open Access Journals (Sweden)

    Jandrić Slavica

    2002-01-01

    Full Text Available Etiology of degenerative joint diseases Etiology of degenerative joint diseases is still not clearly understood and there is no specific management for this group of diseases. Various pathological conditions cause damage of the articular cartilage and lead to clinically and radiographically recognized impairment. Biomechanical, metabolic, genetic factors inflammation and other risk factors contribute to development of osteoarthrosis. Pathophysiology of degenerative joint diseases Osteoarthrosis is characterized by progressive erosion of articular cartilage and bone overgrowth at the joint margins. Cartilage integrity requires balance between synthesis and degradation of matrix components. Chondrocytes react to various mechanical and chemical stresses in order to stabilize and restore the tissue. Failures in stabilizing and restoring the tissue lead to cartilage degeneration that may be irreversibile. For better understanding of conservative management of degenerative joint diseases it is important to know the impact of pathophysiology mechanisms on development of degenerative joint diseases. There is great variability in the rate of progression of erosive processes in articular cartilage in clinical radiographic signs and course of the disease. This is in relation with many factors, as well as with management and response to therapy. Treatment of degenerative joint diseases Treatment should vary depending on the severity of disease and patient's expectations and level of activity. Besides analgesic and anti-inflammatory drugs, conventional and not conventional treatment and techniques can be used for management of osteoarthrosis. Physical therapy and exercises are very important for maintaining muscle strength, joint stability and mobility, but should be closely monitored for optimal efficacy.

  14. PEMISAHAN Zr – Hf SECARA SINAMBUNG MENGGUNAKAN MIXER SETTLER

    Directory of Open Access Journals (Sweden)

    Dwi Biyantoro

    2017-01-01

    Full Text Available ABSTRAK PEMISAHAN Zr – Hf SECARA SINAMBUNG MENGGUNAKANMIXER SETTLER. Telah dilakukan pemisahanZr – Hf secara sinambung menggunakan pengaduk pengenap (mixer settler 16 stage. Larutan umpan adalah zirkon nitrat dengan kadar Zr = 30786 ppm dan Hf = 499 ppm. Ekstraktan dipakai adalah solven 60 % TBP dalam kerosen dan larutan scrubbingyang dipakai adalah asam nitrat 1 M. Umpan masuk pada stageke 5 dikontakkan secara berlawanan arah dengan solven masuk pada stage ke 16 dan larutan scrubbing masuk pada stage ke 1. Tujuan penelitian ini adalah memisahkan unsur Zr dan Hf dari hasil olah pasir zirkon menggunakan solven TBP dengan alat mixer settler16 stage. Analisis umpan dan hasil proses pemisahan untuk zirkonium (Zr dilakukan dengan menggunakan alat pendar sinar-X, sedangkananalisis unsur hafnium (Hf menggunakan Analisis Pengaktifan Neutron (APN. Parameter penelitian dilakukan dengan variasi keasaman asam nitrat dalam umpan dan variasi waktu pada berbagai laju pengadukan. Hasil penelitian pemisahan unsur Zr dengan Hf diperolehkondisi optimum pada keasaman umpan 4 N HNO3, keseimbangan dicapai setelah 3jam dan laju pengadukan 3300 rpm. Hasil ekstrak  unsur zirkon (Zr diperoleh kadar sebesar 28577 ppm dengan efisiensi 92,76 % serta kadar pengotor hafnium (Hf sebesar 95 ppm. Kata Kunci: pemisahan Zr, Hf, ekstraksi, mixer settler, alat pendar sinar-X, APN. ABSTRACT SEPARATION of Zr - Hf CONTINUOUSLY USE THE MIXER SETTLER. Separation of Zr - Hf continuously using mixer settler 16 stage has been done. The feed solution is zircon nitrate concentration of Zr = 30786 ppm  and Hf = 499 ppm. As the solvent used extractant 60 % TBP in 40 % kerosene. Nitric acid solution used srubbing 1 M. The feed entered into stage to 5 is contacted with solvents direction on the stage to 16 and the scrubbing solution enter the stage to 1. The purpose of this study is to separate Zr and Hf of the results from the process of zircon sand using solvent TBP using 16 stage

  15. Epitaxial Thin Films of Y doped HfO2

    Science.gov (United States)

    Serrao, Claudy; Khan, Asif; Ramamoorthy, Ramesh; Salahuddin, Sayeef

    Hafnium oxide (HfO2) is one of a few metal oxides that is thermodynamically stable on silicon and silicon oxide. There has been renewed interest in HfO2 due to the recent discovery of ferroelectricity and antiferroelectricity in doped HfO2. Typical ferroelectrics - such as strontium bismuth tantalate (SBT) and lead zirconium titanate (PZT) - contain elements that easily react with silicon and silicon oxide at elevated temperatures; therefore, such ferroelectrics are not suited for device applications. Meanwhile, ferroelectric HfO2 offers promise regarding integration with silicon. The stable phase of HfO2 at room temperature is monoclinic, but HfO2 can be stabilized in the tetragonal, orthorhombic or even cubic phase by suitable doping. We stabilized Y-doped HfO2 thin films using pulsed laser deposition. The strain state can be controlled using various perovskite substrates and controlled growth conditions. We report on Y-doped HfO2 domain structures from piezo-response force microscopy (PFM) and structural parameters via X-ray reciprocal space maps (RSM). We hope this work spurs further interest in strain-tuned ferroelectricity in doped HfO2.

  16. New strategies for heart failure with preserved ejection fraction: the importance of targeted therapies for heart failure phenotypes.

    Science.gov (United States)

    Senni, Michele; Paulus, Walter J; Gavazzi, Antonello; Fraser, Alan G; Díez, Javier; Solomon, Scott D; Smiseth, Otto A; Guazzi, Marco; Lam, Carolyn S P; Maggioni, Aldo P; Tschöpe, Carsten; Metra, Marco; Hummel, Scott L; Edelmann, Frank; Ambrosio, Giuseppe; Stewart Coats, Andrew J; Filippatos, Gerasimos S; Gheorghiade, Mihai; Anker, Stefan D; Levy, Daniel; Pfeffer, Marc A; Stough, Wendy Gattis; Pieske, Burkert M

    2014-10-21

    The management of heart failure with reduced ejection fraction (HF-REF) has improved significantly over the last two decades. In contrast, little or no progress has been made in identifying evidence-based, effective treatments for heart failure with preserved ejection fraction (HF-PEF). Despite the high prevalence, mortality, and cost of HF-PEF, large phase III international clinical trials investigating interventions to improve outcomes in HF-PEF have yielded disappointing results. Therefore, treatment of HF-PEF remains largely empiric, and almost no acknowledged standards exist. There is no single explanation for the negative results of past HF-PEF trials. Potential contributors include an incomplete understanding of HF-PEF pathophysiology, the heterogeneity of the patient population, inadequate diagnostic criteria, recruitment of patients without true heart failure or at early stages of the syndrome, poor matching of therapeutic mechanisms and primary pathophysiological processes, suboptimal study designs, or inadequate statistical power. Many novel agents are in various stages of research and development for potential use in patients with HF-PEF. To maximize the likelihood of identifying effective therapeutics for HF-PEF, lessons learned from the past decade of research should be applied to the design, conduct, and interpretation of future trials. This paper represents a synthesis of a workshop held in Bergamo, Italy, and it examines new and emerging therapies in the context of specific, targeted HF-PEF phenotypes where positive clinical benefit may be detected in clinical trials. Specific considerations related to patient and endpoint selection for future clinical trials design are also discussed. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  17. A DFT study of temperature dependent dissociation mechanism of HF in HF(H2O)7 cluster

    Indian Academy of Sciences (India)

    Swatantra K Yadav; Hirdyesh Mishra; Ashwani K Tiwari

    2015-10-01

    We report a Density Functional Theoretical (DFT) study of dissociation of Hydrogen Fluoride (HF) in HF(H2O)7 cluster, using B3LYP functional and empirical exchange correlation functional M06-2X along with 6-31+G(d,p) basis set. Dissociation constant, KRP, of HF dissociation and pKa values of HF in cluster at various temperatures have been reported. It has been found that both KRP and pKa are highly dependent on temperature. The variation of pKa with temperature suggests that HF is strong acid at lower temperatures. Our study also reveals that HF is a stronger acid in water cluster than in bulk water. Further, the results obtained by DFT calculations have been compared with the earlier reported results obtained from Monte Carlo (MC) simulation. It is found that DFT results are qualitatively consistent with the results of MC simulation but quantitatively different.

  18. Hf-W chronometry of primitive achondrites

    Science.gov (United States)

    Schulz, T.; Münker, C.; Mezger, K.; Palme, H.

    2010-03-01

    Metal segregation and silicate melting on asteroids are the most incisive differentiation events in the early evolution of planetary bodies. The timing of these events can be constrained using the short-lived 182Hf- 182W radionuclide system. Here we present new 182Hf- 182W data for major types of primitive achondrites including acapulcoites, winonaites and one lodranite. These meteorites are of particular interest because they show only limited evidence for partial melting of silicates and are therefore intermediate between chondrites and achondrites. For acapulcoites we derived a 182Hf- 182W age of Δ tCAI = 4.1 +1.2/ -1.1 Ma. A model age for winonaite separates calculated from the intercept of the isochron defines an age of Δ tCAI = 4.8 +3.1/ -2.6 Ma (assuming a bulk Hf/W ratio of ˜1.2). Both ages most likely define primary magmatic events on the respective parent bodies, such as melting of metal, although metal stayed in place and did not segregate to form a core. A later thermal event is responsible for resetting of the winonaite isochron, yielding an age of Δ tCAI = 14.3 +2.7/ -2.2 Ma, significantly younger than the model age. Assuming a co-genetic relationship between winonaites and silicates present in IAB iron meteorites (based on oxygen isotope composition) and including data by Schulz et al. (2009), a common parent body chronology can be established. Magmatic activity occurred between ˜1.5 and 5 Ma after CAIs. More than 5 Ma later, intensive thermal metamorphism has redistributed Hf-W. Average cooling rates calculated for the winonaite/IAB parent asteroid range between ˜35 and ˜4 K/Ma, most likely reflecting different burial depths. Cooling rates obtained for acapulcoites were ˜40 K/Ma to ˜720 K and then ˜3 K/Ma to ˜550 K. Accretion and subsequent magmatism on the acapulcoite parent body occurred slightly later if compared to most achondrite parent bodies (e.g., angrites, ureilites and eucrites), in this case supporting the concept of an inverse

  19. Pressure induced novel compounds in the Hf-O system from first-principles calculations

    OpenAIRE

    2015-01-01

    Using first-principles evolutionary simulations, we have systematically investigated phase stability in the Hf-O system at pressure up to 120 GPa. New compounds Hf5O2, Hf3O2, HfO and HfO3 are discovered to be thermodynamically stable at certain pressure ranges and a new stable high-pressure phase is found for Hf2O with space group Pnnm and anti-CaCl2-type structure. Both P62m-HfO and P4m2-Hf2O3 show semimetallic character. Pnnm-HfO3 shows interesting structure, simultaneously containing oxide...

  20. The behaviour of REE and Zr-Hf fractionation in the volcanic waters of Nevado del Ruiz system (Colombia)

    Science.gov (United States)

    Inguaggiato, Claudio; Censi, Paolo; Zuddas, Pierpaolo; Makario Londoño, John; Chacón, Zoraida; Alzate, Diego; Brusca, Lorenzo; D'Alessandro, Walter

    2015-04-01

    The geochemical behaviour of Rare Earth Element (REE), Zr and Hf have been investigated in the thermal waters of Nevado del Ruiz volcanic system. These fluids are characterised by a wide range of pH ranging between 1.0 and 8.8. The acidic waters are sulphate dominated with different Cl/SO4 ratios. The Nevado del Ruiz waters allowed to investigate the behaviour of investigated elements in a wide spectrum of pH and chemical composition of water. The important role of the pH and the ionic complexes have been evidenced in the distribution of REE, Zr and Hf in the aqueous phase. The pH rules the precipitation of authigenic oxyhydroxides of Fe, Al producing changes in REE, Zr, Hf amount and strong anomalies of Cerium and Europium. Y-Ho and Zr-Hf (twin pairs) have different behaviour in strong acidic waters with respect to the water with higher pH. Yttrium and Ho have the same behaviour of Zr and Hf in waters with pH near neutral-to-neutral, showing super-chondritic ratios. The twin pairs showed to be sensitive to the co-precipitation and/or adsorption onto the surface of authigenic particulate suggesting an enhanced scavenging of Ho and Hf respect to Y and Zr, leading to super-chondritic ratios. In acidic waters a different behaviour of twin pairs occurs with chondritic Y/Ho ratios (reflecting the Y/Ho ratio of average local rock) and sub-chondritic Zr/Hf ratios. For the first time, Zr and Hf have been investigated in natural acidic fluids to understand the behaviour of these elements in extreme acidic conditions and different major anions chemistry. Zr/Hf molar ratio changes from 4.75 to 49.29 in water with pH<3.6. In strong acidic waters, a different fractionation of Zr and Hf have been recognised as function of major anion contents (Cl and SO4), suggesting the formation of complexes leading to sub-chondritic Zr/Hf molar ratios.

  1. Ferroelectricity of nondoped thin HfO2 films in TiN/HfO2/TiN stacks

    Science.gov (United States)

    Nishimura, Tomonori; Xu, Lun; Shibayama, Shigehisa; Yajima, Takeaki; Migita, Shinji; Toriumi, Akira

    2016-08-01

    We report on the impact of TiN interfaces on the ferroelectricity of nondoped HfO2. Ferroelectric properties of nondoped HfO2 in TiN/HfO2/TiN stacks are shown in capacitance-voltage and polarization-voltage characteristics. The Curie temperature is also estimated to be around 500 °C. The ferroelectricity of nondoped HfO2 clearly appears by thinning HfO2 film down to ˜35 nm. We directly revealed in thermal treatments that the ferroelectric HfO2 film on TiN was maintained by covering the top surface of HfO2 with TiN, while it was followed by a phase transition to the paraelectric phase in the case of the open surface of HfO2. Thus, it is concluded that the ferroelectricity in nondoped HfO2 in this study was mainly driven by both of top and bottom TiN interfaces.

  2. The pathophysiology of lifelong premature ejaculation.

    Science.gov (United States)

    Waldinger, Marcel D

    2016-08-01

    For many decades it has been thought that lifelong premature ejaculation (PE) is only characterized by persistent early ejaculations. Despite enormous progress of in vivo animal research, and neurobiological, genetic and pharmacological research in men with lifelong PE, our current understanding of the mechanisms behind early ejaculations is far from complete. The new classification of PE into four PE subtypes has shown that the symptomatology of lifelong PE strongly differs from acquired PE, subjective PE and variable PE. The phenotype of lifelong PE and therefore also the pathophysiology of lifelong PE is much more complex. A substantial number of men with lifelong PE not only have PE, but also premature erection and premature penile detumescence as part of an acute hypertonic or hypererotic state when engaged in an erotic situation or when making love. As both erectio praecox, ejaculatio praecox, detumescentia praecox, and the hypererotic state are part of the phenotype lifelong PE, it is argued that lifelong PE is not only a disturbance of the timing of ejaculation but also a disturbance of the timing of erection, detumescence and arousal. Since 1998, the pathophysiology of lifelong PE was thought to be mainly mediated by the central serotonergic system in line with genetic polymorphisms of specific serotonergic genes. However, by accepting that lifelong PE is characterized by the reversible hypertonic state the hypothesis of mainly serotonergic dysfunction is no longer tenable. Instead, it has been postulated that the pathophysiology of lifelong PE is mediated by a very complex interplay of central and peripheral serotonergic, dopaminergic, oxytocinergic, endocrinological, genetic and probably also epigenetic factors. Progress in research of lifelong PE can only be accomplished when a stopwatch is used to measure the IELT and the cut-off point of 1 minute for the definition of lifelong PE is maintained. Current use of validated questionnaires, neglect of

  3. The pathophysiology of lifelong premature ejaculation

    Science.gov (United States)

    2016-01-01

    For many decades it has been thought that lifelong premature ejaculation (PE) is only characterized by persistent early ejaculations. Despite enormous progress of in vivo animal research, and neurobiological, genetic and pharmacological research in men with lifelong PE, our current understanding of the mechanisms behind early ejaculations is far from complete. The new classification of PE into four PE subtypes has shown that the symptomatology of lifelong PE strongly differs from acquired PE, subjective PE and variable PE. The phenotype of lifelong PE and therefore also the pathophysiology of lifelong PE is much more complex. A substantial number of men with lifelong PE not only have PE, but also premature erection and premature penile detumescence as part of an acute hypertonic or hypererotic state when engaged in an erotic situation or when making love. As both erectio praecox, ejaculatio praecox, detumescentia praecox, and the hypererotic state are part of the phenotype lifelong PE, it is argued that lifelong PE is not only a disturbance of the timing of ejaculation but also a disturbance of the timing of erection, detumescence and arousal. Since 1998, the pathophysiology of lifelong PE was thought to be mainly mediated by the central serotonergic system in line with genetic polymorphisms of specific serotonergic genes. However, by accepting that lifelong PE is characterized by the reversible hypertonic state the hypothesis of mainly serotonergic dysfunction is no longer tenable. Instead, it has been postulated that the pathophysiology of lifelong PE is mediated by a very complex interplay of central and peripheral serotonergic, dopaminergic, oxytocinergic, endocrinological, genetic and probably also epigenetic factors. Progress in research of lifelong PE can only be accomplished when a stopwatch is used to measure the IELT and the cut-off point of 1 minute for the definition of lifelong PE is maintained. Current use of validated questionnaires, neglect of

  4. Lafora disease: epidemiology, pathophysiology and management.

    LENUS (Irish Health Repository)

    Monaghan, Thomas S

    2010-07-01

    Lafora disease is a rare, fatal, autosomal recessive, progressive myoclonic epilepsy. It may also be considered as a disorder of carbohydrate metabolism because of the formation of polyglucosan inclusion bodies in neural and other tissues due to abnormalities of the proteins laforin or malin. The condition is characterized by epilepsy, myoclonus and dementia. Diagnostic findings on MRI and neurophysiological testing are not definitive and biopsy or genetic studies may be required. Therapy in Lafora disease is currently limited to symptomatic management of the epilepsy, myoclonus and intercurrent complications. With a greater understanding of the pathophysiological processes involved, there is justified hope for future therapies.

  5. Pathophysiology of muscle contractures in cerebral palsy.

    Science.gov (United States)

    Mathewson, Margie A; Lieber, Richard L

    2015-02-01

    Patients with cerebral palsy present with a variety of adaptations to muscle structure and function. These pathophysiologic symptoms include functional deficits such as decreased force production and range of motion, in addition to changes in muscle structure such as decreased muscle belly size, increased sarcomere length, and altered extracellular matrix structure and composition. On a cellular level, patients with cerebral palsy have fewer muscle stem cells, termed satellite cells, and altered gene expression. Understanding the nature of these changes may present opportunities for the development of new muscle treatment therapies.

  6. Heatstroke Pathophysiology: The Energy Depletion Model

    Science.gov (United States)

    1989-06-12

    Pathophysiology: The Energy Depletion Model Roger W. Hubbard, Ph.D., Director Heat Research Division U. S. Army Research Institute of Environmental...Medicine Natick, MA 01760-5007 USA Send correspondence to: Roger W. Hubbard, Ph.D. Director Heat Research Division USARIEM Kansas St Natick, MA 01760...The NaK-Pump. Part B: Celular Asoects J.C. Skou, J.G. Normy, A.B. Maunsback, and M. Esmann (Eds) New York: Alan R. Uss, 1988, pp. 171-194. 54: Lewis

  7. Rho kinases in cardiovascular physiology and pathophysiology.

    Science.gov (United States)

    Loirand, Gervaise; Guérin, Patrice; Pacaud, Pierre

    2006-02-17

    Rho kinases (ROCKs) are the first and the best-characterized effectors of the small G-protein RhoA. In addition to their effect on actin organization, or through this effect, ROCKs have been found to regulate a wide range of fundamental cell functions such as contraction, motility, proliferation, and apoptosis. Abnormal activation of the RhoA/ROCK pathway has been observed in major cardiovascular disorders such as atherosclerosis, restenosis, hypertension, pulmonary hypertension, and cardiac hypertrophy. This review, based on recent molecular, cellular, and animal studies, focuses on the current understanding of ROCK signaling and its roles in cardiovascular physiology and pathophysiology.

  8. [Pathophysiology and classification of pulmonary hypertension].

    Science.gov (United States)

    Sládková, H; Jansa, P; Susa, Z; Aschermann, M

    2004-09-01

    Pulmonary hypertension is present when the mean pulmonary pressure is increased above 25 mm Hg in a rest or above 30 mm Hg during exercise. It is possible to divide it from different point of view. Well known is pathophysiologic classification and Venice classification suggested by WHO symposium 2003. The rise of arterial pulmonary pressure is caused by three essential abnormalities, these are elevated pulmonary vascular resistance, blood flow and pulmonary artery wedge pressure. Vasoconstriction, remodeling of vessels and in situ trombosis are pathogenetic mechanism which contribute to rise of pulmonary hypertension.

  9. Pathophysiology of osteoporosis: new mechanistic insights.

    Science.gov (United States)

    Armas, Laura A G; Recker, Robert R

    2012-09-01

    Understanding of the pathophysiology of osteoporosis has evolved to include compromised bone strength and skeletal fragility caused by several factors: (1) defects in microarchitecture of trabeculae, (2) defective intrinsic material properties of bone tissue, (3) defective repair of microdamage from normal daily activities, and (4) excessive bone remodeling rates. These factors occur in the context of age-related bone loss. Clinical studies of estrogen deprivation, antiresorptives, mechanical loading, and disuse have helped further knowledge of the factors affecting bone quality and the mechanisms that underlie them. This progress has led to several new drug targets in the treatment of osteoporosis.

  10. [Hypercapnic respiratory failure. Pathophysiology, indications for mechanical ventilation and management].

    Science.gov (United States)

    Kreppein, U; Litterst, P; Westhoff, M

    2016-04-01

    Acute hypercapnic respiratory failure is mostly seen in patients with chronic obstructive pulmonary disease (COPD) and obesity hypoventilation syndrome (OHS). Depending on the underlying cause it may be associated with hypoxemic respiratory failure and places high demands on mechanical ventilation. Presentation of the current knowledge on indications and management of mechanical ventilation in patients with hypercapnic respiratory failure. Review of the literature. Important by the selection of mechanical ventilation procedures is recognition of the predominant pathophysiological component. In hypercapnic respiratory failure with a pH pathophysiological situation in patients with OHS or overlap syndrome. If severe respiratory acidosis and hypercapnia cannot be managed by mechanical ventilation therapy alone extracorporeal venous CO2 removal may be necessary. Reports on this approach in awake patients are available. The use of NIV is the predominant treatment in patients with hypercapnic respiratory failure but close monitoring is necessary in order not to miss the indications for intubation and invasive ventilation. Methods of extracorporeal CO2 removal especially in awake patients need further evaluation.

  11. Obesity-hypertension: emerging concepts in pathophysiology and treatment.

    Science.gov (United States)

    Mathew, Boban; Patel, Sanjeev B; Reams, Garry P; Freeman, Ronald H; Spear, Robert M; Villarreal, Daniel

    2007-07-01

    The incidence and prevalence of obesity has risen markedly in the last decade, and this epidemic represents a serious health hazard with significant morbidity and mortality. Although hypertension is recognized as one of the most serious consequences of obesity, its pathophysiology remains incompletely understood. Contemporary research suggests that the recently discovered hormone leptin may represent a common link between these 2 pathologic conditions. Leptin is primarily synthesized and secreted by adipocytes. One of the major functions of this hormone is the control of energy balance. By binding to receptors in the hypothalamus, it reduces food intake and promotes elevation in temperature and energy expenditure. In addition, increasing evidence suggests that leptin, through both direct and indirect actions, may play an important role in cardiovascular and renal functions. Although the relevance of endogenous leptin needs further clarification for the control of renal sodium excretion and vascular tone, it appears to be a potential pressure and volume-regulating factor in normal situations. However, in conditions of chronic hyperleptinemia, such as obesity, leptin may function pathophysiologically for the development of hypertension as well as cardiac and renal disease. Thus, in addition to weight control, reduction of circulating leptin may confer cardiovascular and renal protective effects in patients with obesity-hypertension.

  12. Ghrelin and leptin pathophysiology in chronic kidney disease.

    Science.gov (United States)

    Gunta, Sujana S; Mak, Robert H

    2013-04-01

    Ghrelin is an orexigenic hormone with additional effects on the regulation of inflammation and the cardiovascular system. It may play an important role in the pathogenesis of cachexia/protein-energy wasting (PEW), inflammation and cardiovascular complications in chronic kidney disease (CKD). There are three circulating gene products of ghrelin, namely, acyl ghrelin, des-acyl ghrelin and obestatin, each with individual distinct functions. Perturbations of these circulating ghrelin proteins impact the overall milieu of CKD. Leptin is an anorexigenic hormone which is secreted from the adipocytes and interacts with ghrelin and other appetite-regulating hormones. Leptin also plays a role in regulating inflammation and the cardiovascular system. Indeed, ghrelin and leptin may play yin-and-yang roles in CKD pathophysiology. Clinical trials involving the use of the mimetics or antagonists of these hormones are limited to short-term phase I/II studies. Further understanding of their interactions in CKD pathophysiology is needed for potential large-scale clinical trials, which may impact the quality of life and survival of patients with CKD.

  13. Evidence for Bladder Urothelial Pathophysiology in Functional Bladder Disorders

    Directory of Open Access Journals (Sweden)

    Susan K. Keay

    2014-01-01

    Full Text Available Understanding of the role of urothelium in regulating bladder function is continuing to evolve. While the urothelium is thought to function primarily as a barrier for preventing injurious substances and microorganisms from gaining access to bladder stroma and upper urinary tract, studies indicate it may also function in cell signaling events relating to voiding function. This review highlights urothelial abnormalities in bladder pain syndrome/interstitial cystitis (BPS/IC, feline interstitial cystitis (FIC, and nonneurogenic idiopathic overactive bladder (OAB. These bladder conditions are typified by lower urinary tract symptoms including urinary frequency, urgency, urgency incontinence, nocturia, and bladder discomfort or pain. Urothelial tissues and cells from affected clinical subjects and asymptomatic controls have been compared for expression of proteins and mRNA. Animal models have also been used to probe urothelial responses to injuries of the urothelium, urethra, or central nervous system, and transgenic techniques are being used to test specific urothelial abnormalities on bladder function. BPS/IC, FIC, and OAB appear to share some common pathophysiology including increased purinergic, TRPV1, and muscarinic signaling, increased urothelial permeability, and aberrant urothelial differentiation. One challenge is to determine which of several abnormally regulated signaling pathways is most important for mediating bladder dysfunction in these syndromes, with a goal of treating these conditions by targeting specific pathophysiology.

  14. Psychological effect, pathophysiology, and management of androgenetic alopecia in men.

    Science.gov (United States)

    Stough, Dow; Stenn, Kurt; Haber, Robert; Parsley, William M; Vogel, James E; Whiting, David A; Washenik, Ken

    2005-10-01

    Androgenetic alopecia In men, or male pattern baldness, is recognized increasingly as a physically and psychologically harmful medical condition that can be managed effectively by generalist clinicians. This article discusses the clinical manifestations, epidemiology, physical and psychosocial importance, pathophysiology, diagnosis, and management of androgenetic alopecia in men. Androgenetic alopecia affects at least half of white men by the age of 50 years. Although androgenetic alopecia does not appear to cause direct physical harm, hair loss can result in physical harm because hair protects against sunburn, cold, mechanical injury, and ultraviolet light. Hair loss also can psychologically affect the balding individual and can Influence others' perceptions of him. A progressive condition, male pattern baldness is known to depend on the presence of the androgen dihydrotestosterone and on a genetic predisposition for this condition, but its pathophysiology has not been elucidated fully. Pharmacotherapy, hair transplantation, and cosmetic aids have been used to manage male pattern baldness. Two US Food and Drug Administration-approved hair-loss pharmacotherapies-the potassium channel opener minoxidil and the dihydrotestosterone synthesis inhibitor finasteride--are safe and effective for controlling male pattern baldness with long-term daily use. Regardless of which treatment modality is chosen for male pattern baldness, defining and addressing the patient's expectations regarding therapy are paramount in determining outcome.

  15. Improving Navigation information for the Rotterdam Harbour access through a 3D Model and HF radar

    Science.gov (United States)

    Schroevers, Marinus

    2015-04-01

    The Port of Rotterdam is one of the largest harbours in the world and a gateway to Europe. For the access to Rotterdam harbour, information on hydrodynamic and meteorological conditions is of vital importance for safe and swift navigation. This information focuses on the deep navigation channel in the shallow foreshore, which accommodates large seagoing vessels. Due to a large seaward extension of the Port of Rotterdam area in 2011, current patterns have changed. A re-evaluation of the information needed, showed a need for an improved accuracy of the cross channel currents and swell, and an extended forecast horizon. To obtain this, new information system was designed based on a three dimensional hydrodynamic model which produces a 72 hour forecast. Furthermore, the system will assimilate HF radars surface current to optimize the short term forecast. The project has started in 2013 by specifying data needed from the HF radar. At the same time (temporary) buoys were deployed to monitor vertical current profiles. The HF radar will be operational in July 2015, while the model development starts beginning 2015. A pre operational version of the system is presently planned for the end of 2016. A full operational version which assimilates the HF radar data is planned for 2017.

  16. The Performance and Fouling Control of Submerged Hollow Fiber (HF Systems: A Review

    Directory of Open Access Journals (Sweden)

    Ebrahim Akhondi

    2017-07-01

    Full Text Available The submerged membrane filtration concept is well-established for low-pressure microfiltration (MF and ultrafiltration (UF applications in the water industry, and has become a mainstream technology for surface-water treatment, pretreatment prior to reverse osmosis (RO, and membrane bioreactors (MBRs. Compared to submerged flat sheet (FS membranes, submerged hollow fiber (HF membranes are more common due to their advantages of higher packing density, the ability to induce movement by mechanisms such as bubbling, and the feasibility of backwashing. In view of the importance of submerged HF processes, this review aims to provide a comprehensive landscape of the current state-of-the-art systems, to serve as a guide for further improvements in submerged HF membranes and their applications. The topics covered include recent developments in submerged hollow fiber membrane systems, the challenges and developments in fouling-control methods, and treatment protocols for membrane permeability recovery. The highlighted research opportunities include optimizing the various means to manipulate the hydrodynamics for fouling mitigation, developing online monitoring devices, and extending the submerged HF concept beyond filtration.

  17. Robustness of digitally modulated signal features against variation in HF noise model

    Directory of Open Access Journals (Sweden)

    Shoaib Mobien

    2011-01-01

    Full Text Available Abstract High frequency (HF band has both military and civilian uses. It can be used either as a primary or backup communication link. Automatic modulation classification (AMC is of an utmost importance in this band for the purpose of communications monitoring; e.g., signal intelligence and spectrum management. A widely used method for AMC is based on pattern recognition (PR. Such a method has two main steps: feature extraction and classification. The first step is generally performed in the presence of channel noise. Recent studies show that HF noise could be modeled by Gaussian or bi-kappa distributions, depending on day-time. Therefore, it is anticipated that change in noise model will have impact on features extraction stage. In this article, we investigate the robustness of well known digitally modulated signal features against variation in HF noise. Specifically, we consider temporal time domain (TTD features, higher order cumulants (HOC, and wavelet based features. In addition, we propose new features extracted from the constellation diagram and evaluate their robustness against the change in noise model. This study is targeting 2PSK, 4PSK, 8PSK, 16QAM, 32QAM, and 64QAM modulations, as they are commonly used in HF communications.

  18. Synthesis of Freestanding HfO2 Nanostructures

    Science.gov (United States)

    2011-04-05

    Tang J, Fabbri J, Robinson RD, Zhu Y, Herman IP, Steigerwald ML, Brus LE: Solid-solution nanoparticles:use of a nonhydrolytic sol-gel synthesis to...colloidal HfO2 nanorods. Adv Mater 2007, 19:2608-2612. Page 21 5. Qiu X, Howe JY, Cardoso MB, Polat O, Heller W: Size control of highly ordered HfO2

  19. Parametric excitation of whistler waves by HF heater

    Science.gov (United States)

    Kuo, S. P.; Lee, M. C.

    1989-01-01

    Possible generation of whistler waves by Tromso HF heater is investigated. It is shown that the HF heater wave can parametrically decay into a whistler wave and a Langmuir wave. Since whistler waves may have a broad range of frequency, the simultaneously excited Langmuir waves can have a much broader frequency bandwidth than those excited by the parametric decay instability.

  20. Study of {sup 179}Hf{sup m2} excitation

    Energy Technology Data Exchange (ETDEWEB)

    Vishnevsky, I. N.; Zheltonozhsky, V. A., E-mail: zhelton@kinr.kiev.ua; Savrasov, A. N. [National Academy of Sciences of Ukraine, Institute for Nuclear Research (Ukraine); Mazur, V. M. [National Academy of Sciences of Ukraine, Institute of Electronic Physics (Ukraine)

    2016-12-15

    Isomeric ratios of {sup 179}Hf{sup m2,g} yields in the (γ, n) reaction and the cross section for the {sup 179}Hf{sup m2} population in the (α, p) reaction are measured for the first time at the end-point energies of 15.1 and 17.5 MeV for bremsstrahlung photons and 26 MeV for alpha particles. The results are σ = (1.1 ± 0.11) × 10{sup −27} cm{sup 2} for the {sup 176}Lu(α, p){sup 179}Hf{sup m2} reaction and Y{sub m2}/Y{sub g} = (6.1 ± 0.3) × 10{sup −6} and (3.7 ± 0.2) × 10{sup −6} for the {sup 180}Hf(γ, n){sup 179}Hf{sup m22} reaction at E{sub ep} =15.1 and 17.5 MeV, respectively. The experimental data on the relative {sup 179}Hf{sup m2} yield indicate a single-humped shape of the excitation function for the {sup 180}Hf(γ, n){sup 179}Hf{sup m2} reaction. Simulation is performed using the TALYS-1.4 and EMPIRE-3.2 codes.

  1. Diffusion of Hf and Nb in Zr-19%Nb

    Energy Technology Data Exchange (ETDEWEB)

    Zou, H. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Hood, G.M. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Schultz, R.J. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Matsuura, N. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Roy, J.A. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Jackman, J.A. [CANMET, Ottawa, Ont. (Canada). Met. Sci. and Technol.

    1996-05-01

    Diffusion of Hf and Nb in large-grained bcc Zr-19%Nb has been studied. Diffusion coefficients of Hf, D(Hf), were measured in the range 620-1173 K and D(Nb) was measured at 920 and 1167 K. The Hf diffusion profiles were determined by SIMS and the Nb profiles by microtome sectioning and radio-tracer counting. The Hf data show a smooth, temperature-dependent behaviour through the monotectoid temperature, 875 K, and may be characterised by D{approx}10{sup -9}.exp-1.4 (eV/kT) m{sup 2}/s. D(Nb) tends to be lower than the corresponding values for D(Hf). Overall, diffusion of Hf and Nb are characteristic of diffusion in bcc Zr. Surface hold-up (oxide film) at low temperatures was overcome by using ion-implanted Hf diffusion sources. The results are compared with earlier work and discussed in terms of diffusion mechanisms and the {beta}-phase transformation of commercial Zr-2.5Nb. (orig.).

  2. Obesity and heart failure: epidemiology, pathophysiology, clinical manifestations, and management.

    Science.gov (United States)

    Alpert, Martin A; Lavie, Carl J; Agrawal, Harsh; Aggarwal, Kul B; Kumar, Senthil A

    2014-10-01

    Obesity is a risk factor for heart failure (HF) in both men and women. The mortality risk of overweight and class I and II obese adults with HF is lower than that of normal weight or underweight adults with HF of comparable severity, a phenomenon referred to as the obesity paradox. Severe obesity produces hemodynamic alterations that predispose to changes in cardiac morphology and ventricular function, which may lead to the development of HF. The presence of systemic hypertension, sleep apnea, and hypoventilation, comorbidities that occur commonly with severe obesity, may contribute to HF in such patients. The resultant syndrome is known as obesity cardiomyopathy. Substantial weight loss in severely obese persons is capable of reversing most obesity-related abnormalities of cardiac performance and morphology and improving the clinical manifestations of obesity cardiomyopathy.

  3. The pathophysiology of intrahepatic cholestasis of pregnancy.

    Science.gov (United States)

    Dixon, Peter H; Williamson, Catherine

    2016-04-01

    A number of liver disorders are specific to pregnancy. Amongst these, intrahepatic cholestasis of pregnancy (ICP), also known as obstetric cholestasis (OC), is the commonest, affecting approximately 1 in 140 UK pregnancies. Patients commonly present in the third trimester with severe pruritus and deranged serum liver tests; bile acids are elevated, in severe cases >40 μmol/L. Although the disease is considered relatively benign for the mother, increased rates of adverse fetal outcomes, including stillbirth, are associated with ICP. As our knowledge of the mechanisms underlying bile acid homeostasis has advanced in the last 15 years our understanding of ICP has grown, in particular with respect to genetic influences on susceptibility to the disease, the role of reproductive hormones and their metabolites and the possible identity of the pruritic agents. In this review, we will describe recent advances in the understanding of this condition with a particular emphasis on how aspects of genetic and reproductive hormone involvement in pathophysiology have been elucidated. We also review recent developments regarding our knowledge of placental and fetal pathophysiology and the long-term health consequences for the mother and child. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  4. Inflammation in the pathophysiology of essential hypertension.

    Science.gov (United States)

    Montecucco, Fabrizio; Pende, Aldo; Quercioli, Alessandra; Mach, François

    2011-01-01

    In spite of the huge amount of research recently performed in this area, the pathogenesis of human hypertension remains elusive. Thus, hypertension has to be defined as "essential" for the majority of patients with high blood pressure. Given the lack of animal models useful to investigate essential hypertension, we analyze and discuss both clinical and basic research studies indicating that essential hypertension should be considered as a potential multifactorial inflammatory disease. The pathophysiology of essential hypertension might result from interactions between genetic and environmental factors. Morphological abnormalities in the renal parenchyma and arteries have also been shown to determine hypertension. Inflammatory processes might induce renal vasoconstriction, ischemia and injury that can sustain systemic hypertension. Arterial and tubulointerstitial infiltration of inflammatory cells in response to renal damage might further increase renal and vascular alterations through the production of oxidants and other soluble inflammatory mediators. The present review gives an update regarding the latest research on the possible direct role of inflammation in the pathophysiology of essential hypertension.

  5. Eosinophilic esophagitis: From pathophysiology to treatment.

    Science.gov (United States)

    D'Alessandro, Alessandra; Esposito, Dario; Pesce, Marcella; Cuomo, Rosario; De Palma, Giovanni Domenico; Sarnelli, Giovanni

    2015-11-15

    Eosinophilic esophagitis (EoE) is a chronic immune disease, characterized by a dense eosinophilic infiltrate in the esophagus, leading to bolus impaction and reflux-like symptoms. Traditionally considered a pediatric disease, the number of adult patients with EoE is continuously increasing, with a relatively higher incidence in western countries. Dysphagia and food impaction represent the main symptoms complained by patients, but gastroesophageal reflux-like symptoms may also be present. Esophageal biopsies are mandatory for the diagnosis of EoE, though clinical manifestations and proton pump inhibitors responsiveness must be taken into consideration. The higher prevalence of EoE in patients suffering from atopic diseases suggests a common background with allergy, however both the etiology and pathophysiology are not completely understood. Elimination diets are considered the first-line therapy in children, but this approach appears less effective in adults patients, who often require steroids; despite medical treatments, EoE is complicated in some cases by esophageal stricture and stenosis, that require additional endoscopic treatments. This review summarizes the evidence on EoE pathophysiology and illustrates the safety and efficacy of the most recent medical and endoscopic treatments.

  6. Pathophysiology and management of multivalvular disease

    Science.gov (United States)

    Unger, Philippe; Clavel, Marie-Annick; Lindman, Brian R.; Mathieu, Patrick; Pibarot, Philippe

    2016-01-01

    Multivalvular disease (MVD) is a common condition with a complex pathophysiology, dependent on the specific combination of valve lesions. Diagnosis is challenging as several echocardiographic methods commonly used for the assessment of stenosis or regurgitation have been validated only in patients with single valve disease. Decisions about the timing and type of treatment should be made by a multidisciplinary heart valve team, on a case-by-case basis. Several factors should be considered, including the severity and consequences of the MVD, the patient’s life expectancy and comorbidities, the surgical risk associated with combined valve procedures, the long-term risk of morbidity and mortality associated with multiple valve prostheses, and the likelihood and risk of reoperation. The introduction of transcatheter valve therapies into clinical practice has provided new treatment options for patients with MVD, and decision-making algorithms on how to combine surgical and percutaneous treatment options are evolving rapidly. In this Review, we discuss the pathophysiology, diagnosis, and treatment of MVD, focussing on the combination of valve pathologies that are most often encountered in clinical practice. PMID:27121305

  7. Endocrine FGFs: evolution, physiology, pathophysiology, and pharmacotherapy

    Directory of Open Access Journals (Sweden)

    Nobuyuki eItoh

    2015-09-01

    Full Text Available The human fibroblast growth factor (FGF family comprises 22 structurally related polypeptides that play crucial roles in neuronal functions, development, and metabolism. FGFs are classified as intracrine, paracrine, and endocrine FGFs based on their action mechanisms. Paracrine and endocrine FGFs are secreted signaling molecules by acting via cell-surface FGF receptors (FGFRs. Paracrine FGFs require heparan sulfate as a co-factor for FGFRs. In contrast, endocrine FGFs, comprising FGF19, FGF21, and FGF23, require α−Klotho or β−Klotho as a co-factor for FGFRs. Endocrine FGFs, which are specific to vertebrates, lost heparan sulfate-binding affinity and acquired a systemic signaling system with αKlotho or βKlotho during early vertebrate evolution. The phenotypes of endocrine FGF knockout mice indicate that they play roles in metabolism including bile acid, energy, and phosphate/active vitamin D metabolism. Accumulated evidence for the involvement of endocrine FGFs in human genetic and metabolic diseases also indicates their pathophysiological roles in metabolic diseases, potential risk factors for metabolic diseases, and useful biomarkers for metabolic diseases. The therapeutic utility of endocrine FGFs is currently being developed. These findings provide new insights into the physiological and pathophysiological roles of endocrine FGFs and potential diagnostic and therapeutic strategies for metabolic diseases.

  8. An investigation in rats into the pathophysiological mechanisms of hydrofluoric acid intoxication

    NARCIS (Netherlands)

    Hillen FC; de Wildt DJ; de Jong Y; Meulenbelt J; de Groot G; Boink ABTJ; van Dijk A

    1989-01-01

    De pathofysiologische mechanismen van fluorwaterstof (HF) na blootstelling via de huid zijn nog onduidelijk. Om verbeterde therapeutische maatregelen te kunnen onderzoeken werd een diermodel voor HF toxiciteitsonderzoek ontwikkeld. De toxiciteit van HF werd onderzocht in de geanesthetiseerde en be

  9. Oxygen Recovery in Hf Oxide Films Fabricated by Sputtering

    Institute of Scientific and Technical Information of China (English)

    JIANG Ran; LI Zi-Feng

    2009-01-01

    The chemical structure of ultrathin Hf oxide films (< 10 nm) fabricated by a standard sputtering method is investigated using x-ray spectroscopy and Rutherford backscattering spectroscopy. According to the experiments,oxygen species are impacted to the HfO2/Si interface during the initial sputtering, and then released back to the upper Hf02 region driven by the oxygen concentration grads. A vacuum annealing can greatly enhance this recovery process. Additionally, significant SiO2 reduction in the interface is observed after the vacuum annealing for the thick HfO2 films in our experiment. It might be an effective method to confine the interracial layer thickness by sputtering thick HfO2 in no-oxygen ambient.

  10. Crystal structure of Si-doped HfO2

    Science.gov (United States)

    Zhao, Lili; Nelson, Matthew; Aldridge, Henry; Iamsasri, Thanakorn; Fancher, Chris M.; Forrester, Jennifer S.; Nishida, Toshikazu; Moghaddam, Saeed; Jones, Jacob L.

    2014-01-01

    Si-doped HfO2 was prepared by solid state synthesis of the starting oxides. Using Rietveld refinement of high resolution X-ray diffraction patterns, a substitutional limit of Si in HfO2 was determined as less than 9 at. %. A second phase was identified as Cristobalite (SiO2) rather than HfSiO4, the latter of which would be expected from existing SiO2-HfO2 phase diagrams. Crystallographic refinement with increased Si-dopant concentration in monoclinic HfO2 shows that c/b increases, while β decreases. The spontaneous strain, which characterizes the ferroelastic distortion of the unit cell, was calculated and shown to decrease with increasing Si substitution.

  11. The (178m2)Hf Controversy

    Energy Technology Data Exchange (ETDEWEB)

    Becker, J A; Gemmell, D S; Schiffer, J P; Wilhelmy, J B

    2003-07-24

    Since its discovery in the 1960's the {sup 178m2}Hf isomer has garnered high attention from both the basic and applied communities in nuclear science. It's combination of high spin (16+), long half life (31 yrs), and high excitation energy (2.446 MeV) offer unique possibilities as an energy storage medium. Interest in the isomer was rekindled beginning in 1999 when a series of publications began to appear from a group (referred to here as the ''Texas collaboration'') primarily based at the University of Texas, Dallas [1]. They reported observations that some of the stored energy could be released (''triggered'') when the isomer was exposed to a fluence of photons in the energy range {approx}10 to {approx}60 keV. The implications of this observation are profound. Even though the claimed cross section for the process was {approx}7 orders of magnitude greater than would be predicted from the known systematics of photon absorption by nuclei in this mass range [2], such a highly efficient method for triggering the isomeric deexcitation immediately suggested applications utilizing the explosive or the controlled gradual energy release from a very compact source. The prospect of such applications has focused considerable interest on realizing the promise that is implicit in the reported observations. However, two experiments performed by a group from ANL/LANL/LLNL at the Advanced Photon Source at Argonne (the ''APS collaboration'') reported negative results for the observation of any photon-triggered deexcitation of the {sup 178m2}Hf isomer [3]. This has led to a continued controversy, where both sides have adamantly defended their observations. At this point an outsider has difficulty determining whether there is indeed a triggering effect that should be pursued energetically with substantial resources, or whether the phenomenon consists of overly optimistic interpretation of data.

  12. Diabetes mellitus and atrial fibrillation: Pathophysiological mechanisms and potential upstream therapies.

    Science.gov (United States)

    Goudis, Christos A; Korantzopoulos, Panagiotis; Ntalas, Ioannis V; Kallergis, Eleftherios M; Liu, Tong; Ketikoglou, Dimitrios G

    2015-04-01

    Diabetes mellitus (DM) represents one of the most important risk factors for atrial fibrillation (AF) while AF is a strong and independent marker of overall mortality and cardiovascular morbidity in diabetic patients. Autonomic, electrical, electromechanical, and structural remodeling, including oxidative stress, connexin remodeling and glycemic fluctuations seem to be implicated in AF pathophysiology in the setting of DM. The present review highlights the association between DM and AF, provides a comprehensive overview of the responsible pathophysiological mechanisms and briefly discusses potential upstream therapies for DM-related atrial remodeling.

  13. Pulmonary pathophysiology and lung mechanics in anesthesiology: a case-based overview.

    Science.gov (United States)

    Vidal Melo, Marcos F; Musch, Guido; Kaczka, David W

    2012-12-01

    Anesthesia, surgical requirements, and patients' unique pathophysiology all combine to make the accumulated knowledge of respiratory physiology and lung mechanics vital in patient management. This article take a case-based approach to discuss how the complex interactions between anesthesia, surgery, and patient disease affect patient care with respect to pulmonary pathophysiology and clinical decision making. Two disparate scenarios are examined: a patient with chronic obstructive pulmonary disease undergoing a lung resection, and a patient with coronary artery disease undergoing cardiopulmonary bypass. The impacts of important concepts in pulmonary physiology and respiratory mechanics on clinical management decisions are discussed.

  14. Ferroelectricity-modulated resistive switching in Pt/Si:HfO2/HfO2-x /Pt memory

    Science.gov (United States)

    Ran, Jiang; Xianghao, Du; Zuyin, Han

    2016-08-01

    It is investigated for the effect of a ferroelectric Si:HfO2 thin film on the resistive switching in a stacked Pt/Si:HfO2/highly-oxygen-deficient HfO2-x /Pt structure. Improved resistance performance was observed. It was concluded that the observed resistive switching behavior was related to the modulation of the width and height of a depletion barrier in the HfO2-x layer, which was caused by the Si:HfO2 ferroelectric polarization field effect. Reliable switching reproducibility and long data retention were observed in these memory cells, suggesting their great potential in non-volatile memories applications with full compatibility and simplicity. Project supported by the National Natural Science Foundation of China (No. 11374182), the Natural Science Foundation of Shandong Province (No. ZR2012FQ012), and the Jinan Independent Innovation Projects of Universities (No. 201303019).

  15. One level up: abnormal proteolytic regulation of IGF activity plays a role in human pathophysiology

    DEFF Research Database (Denmark)

    Argente, Jesús; Chowen, Julie A; Pérez-Jurado, Luis A

    2017-01-01

    The discovery of a mutation in a specific gene can be very important for determining the pathophysiology underlying the disease of a patient and may also help to decide the best treatment protocol on an individual basis. However, sometimes the discovery of mutations in new proteins advances our c...

  16. Hypertension and coarctation of the aorta: an inevitable consequence of developmental pathophysiology.

    Science.gov (United States)

    Kenny, Damien; Polson, Jaimie W; Martin, Robin P; Paton, Julian F R; Wolf, Andrew R

    2011-05-01

    Patients with coarctation of the aorta develop early onset hypertension in spite of early effective repair. This is associated with significant morbidity and is arguably the single most important outcome variable in this patient group. We discuss the potential pathophysiological mechanisms involved in the development of hypertension with clinical reference to monozygotic twins, and review potential strategies for therapy and prevention in this setting.

  17. Curative effect of HF10 on liver and peritoneal metastasis mediated by host antitumor immunity

    Directory of Open Access Journals (Sweden)

    Hotta Y

    2017-03-01

    Full Text Available Yoshihiro Hotta,1 Hideki Kasuya,2 Itzel Bustos,2 Yoshinori Naoe,2 Toru Ichinose,2 Maki Tanaka,3 Yasuhiro Kodera1 1Department of Surgery II, 2Cancer Immune Therapy Research Center, Nagoya University Graduate School of Medicine, Nagoya, 3Takara Bio Inc., Otsu, Japan Background: HF10 is a highly attenuated type 1 herpes simplex virus (HSV with proven effective oncolytic effect. Previous investigations have demonstrated that colon cancer mice model treated with HF10 not only had better survival but were also resistant to the reimplantation of the antitumor effect mediated by host antitumor immunity. Importantly, it has also been noted that in mice with antitumors implanted on both sides of the back, an injection of HF10 on only one side strongly restrains not only the injected antitumor but also the non-injected ones.Materials and methods: MC26 colon cancer cells were injected subcutaneously into the back, spleen, and intraperitoneal region of metastasis model mice. Antitumor volume and survival rate were monitored. To measure cytotoxic T lymphocytes (CTL cytotoxicity against MC26, lymphocytes were extracted from the spleens of the peritoneal metastasis model mice as well as from the thymus of the liver metastasis model mice. The expression of interferon gamma was examined by enzyme-linked immunospot assay. Samples from the liver metastasis model mice were subjected to polymerase chain reaction to quantify the level of HSV genomes.Results: HF10 was injected only on the back antitumor; however, a antitumor-suppressor effect was observed against liver and peritoneal metastases. When HF10 genome was measured, we observed lower genome on liver metastases compared to back antitumor genome quantity. CTL activity against MC26 was also observed. These results indicate that local administration of HF10 exerts a curative effect on systemic disease, mediated by host antitumor immunity.Conclusion: HF10 local administration stimulates antitumor immunity to

  18. Impact of Plasma Kynurenine Level on Functional Capacity and Outcome in Heart Failure - Results From Studies Investigating Co-morbidities Aggravating Heart Failure (SICA-HF).

    Science.gov (United States)

    Konishi, Masaaki; Ebner, Nicole; Springer, Jochen; Schefold, Joerg C; Doehner, Wolfram; Dschietzig, Thomas Bernd; Anker, Stefan D; von Haehling, Stephan

    2016-12-22

    Kynurenine is a circulating metabolite from the essential amino acid tryptophan. Accelerated degradation of kynurenine in skeletal muscle has been reported to provide an anti-inflammatory effect. The aim of this study was to investigate the association between blood kynurenine and muscle mass/function in patients with heart failure (HF), in whom diseased muscle mass/function plays a pathophysiological role.Methods and Results:Plasma kynurenine was assessed in 249 patients with HF (67±11 years, 21% women) and in 45 controls from the SICA-HF study. Kynurenine was higher in 173 HF patients with reduced ejection fraction (EF) and in 76 patients with preserved EF than controls (3.5±1.5, 3.4±1.3, and 2.4±1.1 μmol/L, P<0.001). In HF patients, kynurenine had an inverse association with handgrip strength (r=-0.26, P<0.01), peak oxygen consumption (r=-0.29, P<0.01), 6-min walk distance (r=-0.23, P<0.01), and had a positive association with kidney and liver function parameters. No correlation was observed between kynurenine and lean mass. On multivariable linear regression analysis, a significant association was noted between kynurenine and peak oxygen consumption even after adjustment for age, gender, BMI, and hemoglobin (β=-0.23, P<0.001). Patients with higher kynurenine were at higher risk of death (adjusted HR, 1.46 per 1 μmol/L, P<0.01). In stable HF patients, plasma kynurenine was inversely correlated with muscle strength and functional capacity as well as with liver and kidney function.

  19. Neuropeptides in Alzheimer's disease: from pathophysiological mechanisms to therapeutic opportunities.

    Science.gov (United States)

    Van Dam, Debby; Van Dijck, Annemie; Janssen, Leen; De Deyn, Peter Paul

    2013-06-01

    Neuropeptides are found throughout the entire nervous system where they can act as neurotransmitter, neuromodulator or neurohormone. In those functions, they play important roles in the regulation of cognition and behavior. In brain disorders like Alzheimer's disease (AD), where abnormal cognition and behavior are observed, the study of neuropeptides is particularly interesting since altered neuropeptides can function as biomarkers or as targets for new medication. In this article neuropeptides with relevance to AD are listed and their influence on cognitive and behavioral disturbances is discussed. Findings from human cerebrospinal fluid and brain tissue, and AD mouse models are described and related to the pathophysiology and symptomatology of the disease. In the past, clinical trials with neuropeptides have often failed due to insufficient delivery to the brain. Therefore, new strategies to target the brain with peptide drugs are also covered.

  20. [Pathophysiological mechanism of the developing radicular cyst of the jaw].

    Science.gov (United States)

    Colić, S; Jurisić, M; Jurisić, V

    2008-01-01

    The radicular cysts are result of inflammatory process in the periapical tissues associated with necrotic and infected pulps. Humoral and cellular immune responses play a central role in the pathogenesis of these lesions. The most important role in the growth of these lesion have proinflammatore cytokine TNF-alpha, IL-1 and IL-6. Cytokine can be secreted by macrophages, monocytes and other cells of the immune system and can participate in skeletal homeostasis including osteoclastic formation, and bone resorption in maxillofacial region. The aim of this study is to give a consise rewiew for mechanism of growth of maxilofacial radicular cysts, indicated of clinical aspect, as well as expalined role of cytokine in this pathophysiology process.

  1. Hypertension and atrial fibrillation: epidemiology, pathophysiology and therapeutic implications.

    Science.gov (United States)

    Lau, Y-F; Yiu, K-H; Siu, C-W; Tse, H-F

    2012-10-01

    Hypertension is one of the most important risk factors associated with atrial fibrillation (AF) and increased the risk of cardiovascular events in patients with AF. However, the pathophysiological link between hypertension and AF is unclear. Nevertheless, this can be explained by the hemodynamic changes of the left atrium secondary to long standing hypertension, resulting in elevated left atrium pressure and subsequently left atrial enlargement. Moreover, the activation of renin-angiotensin-aldosterone system (RAAS) activation in patients with hypertension induces left atrial fibrosis and conduction block in the left atrium, resulting in the development of AF. Accordingly, recent studies have shown that effective blockage of RAAS by angiotensin converting enzyme inhibitors or angiotensin receptor antagonist may be effective in both primary and secondary prevention of AF in patients with hypertension, although with controversies. In addition, optimal antithrombotic therapy, blood pressure control as well as rate control for AF are key to the management of patients with AF.

  2. Update on pathophysiology and treatment of hypertension in the elderly.

    Science.gov (United States)

    Cohen, Debbie L; Townsend, Raymond R

    2011-10-01

    Hypertension is common in the elderly, and its prevalence increases with aging. The vascular system is a prototypical aging tissue, and arterial stiffness plays a major role in hypertension as the individual ages. Some unique aging changes in the nitric oxide and angiotensin II pathways are particularly important for vascular aging. Studies focusing on direct measures of vascular stiffness have increased understanding of the pathophysiology behind increased arterial stiffness. Goal blood pressure in the elderly is debated, but based on current outcome data, a goal blood pressure of 150/80-90 mm Hg is reasonable in at least the very elderly. This review discusses in detail the various landmark hypertension studies in the elderly. We recommend use of thiazide diuretics, long-acting calcium channel blockers, and angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers as either monotherapy or in combination, with beta-blockers reserved for patients with specific indications.

  3. Role of renal vascular potassium channels in physiology and pathophysiology

    DEFF Research Database (Denmark)

    Salomonsson, Max; Brasen, Jens Christian; Sorensen, Charlotte Mehlin

    2017-01-01

    The control of renal vascular tone is important for the regulation of salt and water balance, blood pressure and the protection against damaging elevated glomerular pressure. The K+ conductance is a major factor in the regulation of the membrane potential (Vm ) in vascular smooth muscle (VSMC......) and endothelial cells (EC). The vascular tone is controlled by Vm via its effect on the opening probability of voltage operated Ca2+ channels (VOCC) in VSMC. When K+ conductance increases Vm becomes more negative and vasodilation follows, while deactivation of K+ channels leads to depolarization...... the ambiguous in vitro and in vivo results. We discuss the role of single types of K+ channels and the integrated function of several classes. We also deal with the possible role of renal vascular K+ channels in the pathophysiology of hypertension, diabetes mellitus and sepsis. This article is protected...

  4. [Neurophysiology and ageing. Definition and pathophysiological foundations of cognitive impairment].

    Science.gov (United States)

    Borrás Blasco, Consuelo; Viña Ribes, José

    2016-06-01

    Brain ageing is produced by various morphological, biochemical, metabolic and circulatory changes, which are reflected in functional changes, whose impact depends on the presence or absence of cognitive impairment. Because of brain plasticity, together with redundancy of the distinct cerebral circuits, age- related deterioration of the brain at various levels does not always translate into loss of brain function. However, when the damage exceeds certain thresholds, there is age-related cognitive impairment, which increases the risk of developing various neurodegenerative diseases such as Alzheimer disease. Genetics, together with lifestyle, diet, and environmental factors, etc, can trigger the development of these diseases, which provoke cognitive impairment. This article discusses the most important age-related changes in the brain, as well as the pathophysiological foundations of cognitive impairment. Copyright © 2016 Sociedad Española de Geriatría y Gerontología. Publicado por Elsevier España, S.L.U. All rights reserved.

  5. Differences in pathophysiology between rheumatoid arthritis and ankylosing spondylitis.

    Science.gov (United States)

    Lories, R J; Baeten, D L P

    2009-01-01

    Rheumatoid arthritis and ankylosing spondylitis are common and severe chronic inflammatory skeletal diseases. Recognizing the differences rather than emphasizing similarities is important for a better understanding of the disease processes, the identification of specific therapeutic targets and in the long-term better treatment options for the individual patients. We discuss a number of pathophysiological differences between rheumatoid arthritis and ankylosing spondylitis by looking at the anatomical characteristics, differences and similarities in the autoimmune and autoinflammatory reactions, association with other immune mediated inflammatory diseases, structural outcome, and their potential significance for further therapeutic developments. Further research into the differences between these diseases should focus on the specific nature of the immune/inflammatory components, the role of resident cells in the joint and joint-associated tissues, the types and mechanisms of tissue remodeling and the characteristics of the articular cartilage. Better insights into their individual characteristics may lead to better therapeutic strategies, specific targets and useful biomarkers.

  6. Myasthenia gravis: new therapeutic approaches based on pathophysiology.

    Science.gov (United States)

    Lewis, Richard A

    2013-10-15

    Over the past 40 years Dr. Robert Lisak has made important contributions to our understanding of the pathophysiology and therapy of myasthenia gravis. This review will touch upon some of his work as it discusses current therapies and the potential for new treatments based on the evolving knowledge of the underlying basis of the disease. The recognition of different immune mechanisms that can cause the phenotype that we acknowledge as myasthenia gravis coincides with the introduction of monoclonal antibodies and other new therapies that can target specific aspects of the disease. This has raised our hopes for treatments that will have less side effects and be more effective. In some cases these hopes have been realized. In other instances, the situation remains a "work in progress". Dr. Lisak's work and teachings remain cogent to our modern approach to this classic immunologic disease. © 2013.

  7. [Is iron important in heart failure?].

    Science.gov (United States)

    Murín, Ján; Pernický, Miroslav

    2015-12-01

    Iron deficiency is a frequent comorbidity in a patient with chronic heart failure, and it associates with a worse prognosis of that patient. Mainly worse quality of life and more rehospitalizations are in these iron deficient patients. Iron metabolism is rather complex and there is some new information concerning this complexity in heart failure. We distinquish an absolute and a functional iron deficiency in heart failure. It is this deficit which is important and not as much is anemia important here. Prevalence of anaemia in heart failure is about 30-50%, higher it is in patients suffering more frequently heart failure decompensations. Treatment of iron deficiency is important and it improves prognosis of these patients. Most experiences there are with i.v. iron treatment (FERRIC HF, FAIR HF and CONFIRM HF studies), less so with per oral treatment. There are no clinical trials which analysed mortality influences.

  8. An overview of the Charcot foot pathophysiology.

    Science.gov (United States)

    Kaynak, Gökhan; Birsel, Olgar; Güven, Mehmet Fatih; Oğüt, Tahir

    2013-01-01

    Charcot arthropathy of the foot is a rare but devastating complication of diabetes that remains to be a challenging issue for the foot and ankle surgeons. Charcot foot fails to be an obvious diagnostic option that comes to mind, even in a pathognomonic clinical appearance. The rarity of the disorder, more common pathologies that mimic the condition, and the self-limiting prognosis deviate the clinician from the right diagnosis. The clinical challenges in the diagnosis of Charcot foot require in-depth investigations of its enigmatic nature to establish useful guidelines. Yet, this goal seems to be beyond reach, without a holistic view of the immense literature concerning the pathophysiology of the disorder. The primary objective of this article is to put together and review the recent advancements about the etiology and intrinsic mechanisms of diabetic Charcot foot.

  9. An overview of the Charcot foot pathophysiology

    Directory of Open Access Journals (Sweden)

    Gökhan Kaynak

    2013-08-01

    Full Text Available Charcot arthropathy of the foot is a rare but devastating complication of diabetes that remains to be a challenging issue for the foot and ankle surgeons. Charcot foot fails to be an obvious diagnostic option that comes to mind, even in a pathognomonic clinical appearance. The rarity of the disorder, more common pathologies that mimic the condition, and the self-limiting prognosis deviate the clinician from the right diagnosis. The clinical challenges in the diagnosis of Charcot foot require in-depth investigations of its enigmatic nature to establish useful guidelines. Yet, this goal seems to be beyond reach, without a holistic view of the immense literature concerning the pathophysiology of the disorder. The primary objective of this article is to put together and review the recent advancements about the etiology and intrinsic mechanisms of diabetic Charcot foot.

  10. The role of ADAMs in disease pathophysiology.

    LENUS (Irish Health Repository)

    Duffy, Michael J

    2012-02-01

    The ADAMs are a family of multidomain transmembrane and secreted proteins involved in both proteolysis and cell adhesion. Altered expression of specific ADAMs is implicated in the pathophysiology of several diseases including rheumatoid arthritis, Alzheimer\\'s disease, cardiac hypertrophy, asthma and cancer. Of these different diseases, it is in cancer where most research has been carried out. Multiple ADAMs, including ADAM-9, ADAM-10, ADAM-12, ADAM-15 and ADAM-17, have been shown to play a role in either cancer formation or progression. Consistent with these findings, increased expression of specific ADAMs in several cancer types was found to correlate with features of aggressive disease and poor prognosis. Currently, selective ADAM inhibitors against ADAM-10 and ADAM-17 are undergoing clinical trials for the treatment of cancer. Further work is required in order to establish a causative role for ADAMs in rheumatoid arthritis, Alzheimer\\'s disease, cardiac hypertrophy and asthma.

  11. Cell volume regulation: physiology and pathophysiology

    DEFF Research Database (Denmark)

    Lambert, I H; Hoffmann, E K; Pedersen, Stine Helene Falsig

    2008-01-01

    not only under physiological conditions, e.g. following accumulation of nutrients, during epithelial absorption/secretion processes, following hormonal/autocrine stimulation, and during induction of apoptosis, but also under pathophysiological conditions, e.g. hypoxia, ischaemia and hyponatremia....../hypernatremia. On the other hand, it has recently become clear that an increase or reduction in cell volume can also serve as a specific signal in the regulation of physiological processes such as transepithelial transport, cell migration, proliferation and death. Although the mechanisms by which cell volume perturbations...... are sensed are still far from clear, significant progress has been made with respect to the nature of the sensors, transducers and effectors that convert a change in cell volume into a physiological response. In the present review, we summarize recent major developments in the field, and emphasize...

  12. Autism: Pathophysiology and Promising Herbal Remedies.

    Science.gov (United States)

    Bahmani, Mahmoud; Sarrafchi, Amir; Shirzad, Hedayatollah; Rafieian-Kopaei, Mahmoud

    2016-01-01

    Autism is a comprehensive growth abnormality in which social skills, language, communication, and behavioral skills are developed with delay and as diversionary. The reasons for autism are unclear, but various theories of genetics, immunity, biological, and psychosocial factors have been proffered. In fact, autism is a complex disorder with distinct causes that usually co-occur. Although no medicine has been recognized to treat this disorder, pharmacological treatments can be effective in reducing its signs, such as self-mutilation, aggression, repetitive and stereotyped behaviors, inattention, hyperactivity, and sleeping disorders. Recently, complementary and alternative approaches have been considered to treat autism. Ginkgo biloba is one of the most effective plants with an old history of applications in neuropsychological disorders which recently is used for autism. The present review discusses the recent findings, pathophysiology, and etiology of autism and thereafter addresses the promising results of herbal remedies.

  13. Role of leukotrienes in asthma pathophysiology

    DEFF Research Database (Denmark)

    Bisgaard, H

    2000-01-01

    -line anti-inflammatory therapy for asthma management. However, in some patients, especially children, the high doses of corticosteroids that may be required to control features of hyperresponsiveness, including exercise-induced asthma, raise safety concerns. Thus, there is a need for complementary anti......Inflammation is an essential component of asthma pathophysiology. While beta(2)-agonists are often used for short-term relief of acute bronchospasm, anti-inflammatory agents are required for the long-term management of chronic inflammation in this disease. Corticosteroids have emerged as the first......-inflammatory, steroid-sparing agents in asthma therapy. Several inflammatory mediators have been targeted in an attempt to thwart this inflammatory process, but so far with little success. The cysteinyl leukotrienes (CysLT), LTC(4), LTD(4), and LTE(4), have been shown to be essential mediators in asthma, making them...

  14. Pathophysiology, Clinical, and Therapeutic Aspects of Narcolepsy

    Directory of Open Access Journals (Sweden)

    Pinar Guzel Ozdemir

    2014-09-01

    Full Text Available Narcolepsy is a lifelong sleep disorder characterized by excessive daytime sleepiness, cataplexy, hypnagogic hallucination, and sleep paralysis. The exact cause remains unknown, but there is significant evidence that hypocretin deficiency plays an integral role. There have been advances in the understanding of the pathogenesis of narcolepsy. It has a negative effect on the quality of life and can restrict the patients from certain careers and activities. Diagnosis relies on patient history and objective data gathered from polysomnography and multiple sleep latency testing. Treatment focuses on symptom relief through medication, education, and behavioral modification. Both classic pharmacological treatments as well as newer options have significant problems, especially because of side effects and abuse potential. Some novel modalities are being examined to expand options for treatment. In this review, the pathophysiological, clinical, and pharmacotherapeutic aspects of narcolepsy are discussed. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2014; 6(3.000: 271-283

  15. Eyelid aging: pathophysiology and clinical management

    Directory of Open Access Journals (Sweden)

    Renato Wendell Damasceno

    2015-10-01

    Full Text Available ABSTRACTLife expectancy is increasing in most countries. With increasing age, many individuals may develop involutional ophthalmic diseases, such as eyelid aging. Dermatochalasis, ptosis, ectropion, and entropion are common disorders in middle-aged and older adults. This review outlines the pathophysiology and clinical management of these involutional eyelid disorders. Recently, a decrease in elastic fibers with ultrastructural abnormalities and an overexpression of elastin-degrading enzymes have been demonstrated in involutional ectropion and entropion. This may be the consequence of local ischemia, inflammation, and/or chronic mechanical stress. Eyelid aging with progressive loss of tone and laxity may affect the ocular surface and adnexal tissues, resulting in different clinical symptoms and signs. Surgical management depends on the appropriate correction of the underlying anatomical defect.

  16. Task-specific dystonia: pathophysiology and management.

    Science.gov (United States)

    Sadnicka, Anna; Kassavetis, Panagiotis; Pareés, Isabel; Meppelink, Anne Marthe; Butler, Katherine; Edwards, Mark

    2016-09-01

    Task-specific dystonia is a form of isolated focal dystonia with the peculiarity of being displayed only during performance of a specific skilled motor task. This distinctive feature makes task-specific dystonia a particularly mysterious and fascinating neurological condition. In this review, we cover phenomenology and its increasingly broad-spectrum risk factors for the disease, critically review pathophysiological theories and evaluate current therapeutic options. We conclude by highlighting the unique features of task-specific dystonia within the wider concept of dystonia. We emphasise the central contribution of environmental risk factors, and propose a model by which these triggers may impact on the motor control of skilled movement. By viewing task-specific dystonia through this new lens which considers the disorder a modifiable disorder of motor control, we are optimistic that research will yield novel therapeutic avenues for this highly motivated group of patients.

  17. [Aerosinusitis: part 1: Fundamentals, pathophysiology and prophylaxis].

    Science.gov (United States)

    Weber, R; Kühnel, T; Graf, J; Hosemann, W

    2014-01-01

    The relevance of aerosinusitis stems from the high number of flight passengers and the impaired fitness for work of the flight personnel. The frontal sinus is more frequently affected than the maxillary sinus and the condition generally occurs during descent. Sinonasal diseases and anatomic variations leading to obstruction of paranasal sinus ventilation favor the development of aerosinusitis. This Continuing Medical Education (CME) article is based on selective literature searches of the PubMed database (search terms: "aerosinusitis", "barosinusitis", "barotrauma" AND "sinus", "barotrauma" AND "sinusitis", "sinusitis" AND "flying" OR "aviator"). Additionally, currently available monographs and further articles that could be identified based on the publication reviews were also included. Part 1 presents the pathophysiology, symptoms, risk factors, epidemiology and prophylaxis of aerosinusitis. In part 2, diagnosis, conservative and surgical treatment will be discussed.

  18. Treatment of cellulite: Part I. Pathophysiology.

    Science.gov (United States)

    Khan, Misbah H; Victor, Frank; Rao, Babar; Sadick, Neil S

    2010-03-01

    Cellulite is a topographic skin change that is nearly ubiquitous in postpubertal women. Treatment remains elusive. The various treatments currently available are only partially or temporarily effective. Newer therapeutic modalities continue to evolve without much understanding of the complex nature of cellulite. The successful treatment of cellulite will ultimately depend upon our understanding of the pathophysiology of cellulite adipose tissue. Part I of this two-part series on cellulite reviews how the concept and perception of cellulite has evolved over time and its proposed etiologies. The article also focuses on the physiology of human adipose tissue, particularly regarding cellulite. Copyright 2009 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

  19. [Pathophysiology and treatment of orofacial pain.

    Science.gov (United States)

    Shinoda, Masamichi; Noma, Noboru

    2017-01-01

    "Pain" is one of body defense mechanisms and crucial for the life support. However, orofacial pain such as myofascial pain syndrome, burning mouth syndrome and trigeminal neuralgia plays no part in body defense mechanisms and requires therapeutic intervention. Recent studies have indicated that plastic changes in the activities of trigeminal neurons, satellite glial cells in trigeminal ganglion, secondary neurons, microglia and astrocytes in trigeminal spinal subnucleus following orofacial inflammation and trigeminal nerve injury are responsible for orofacial pain mechanisms. Clinically, it is well known that the etiologic differential diagnosis which consists of careful history-taking and physical examination is essential for therapeutic decision in patients with orofacial pain. This report outlines the current knowledge on the pathophysiology, diagnosis, treatment of orofacial pain.

  20. New insights into pathophysiology of vestibular migraine

    Directory of Open Access Journals (Sweden)

    Juan Manuel Espinosa-Sanchez

    2015-02-01

    Full Text Available Vestibular migraine (VM is a common disorder in which genetic, epigenetic and environmental factors probably contribute to its development. The pathophysiology of VM is unknown; nevertheless in the last few years, several studies are contributing to understand the neurophysiological pathways involved in VM. The current hypotheses are mostly based on the knowledge of migraine itself. The evidence of trigeminal innervation of the labyrinth vessels and the localization of vasoactive neuropeptides in the perivascular afferent terminals of these trigeminal fibers support the involvement of the trigemino-vascular system. The neurogenic inflammation triggered by activation of the trigeminal-vestibulocochlear reflex, with the subsequent inner ear plasma protein extravasation and the release of inflammatory mediators, can contribute to a sustained activation and sensitization of the trigeminal primary afferent neurons explaining VM symptoms. The reciprocal connections between brainstem vestibular nuclei and the structures that modulate trigeminal nociceptive inputs (rostral ventromedial medulla, ventrolateral periaqueductal grey, locus coeruleus and nucleus raphe magnus are critical to understand the pathophysiology of VM. Although cortical spreading depression can affect cortical areas involved in processing vestibular information, functional neuroimaging techniques suggest a dysmodulation in the multimodal sensory integration and processing of vestibular and nociceptive information, resulting from a vestibulo-thalamo-cortical dysfunction, as the pathogenic mechanism underlying VM. The elevated prevalence of VM suggests that multiple functional variants may confer a genetic susceptibility leading to a dysregulation of excitatory-inhibitory balance in brain structures involved in the processing of sensory information, vestibular inputs and pain. The interactions among several functional and structural neural networks could explain the pathogenic

  1. Erythrodermic psoriasis: pathophysiology and current treatment perspectives

    Directory of Open Access Journals (Sweden)

    Singh RK

    2016-07-01

    Full Text Available Rasnik K Singh,1 Kristina M Lee,2 Derya Ucmak,2 Merrick Brodsky,3 Zaza Atanelov,4 Benjamin Farahnik,5 Michael Abrouk,3 Mio Nakamura,2 Tian Hao Zhu,6 Wilson Liao2 1Department of Medicine, University of California – Los Angeles, David Geffen School of Medicine, Los Angeles, 2Department of Dermatology, University of California – San Francisco, San Francisco, 3Department of Medicine, University of California – Irvine, School of Medicine, Irvine, CA, 4Department of Medicine, New York Medical College, Valhalla, NY, 5Department of Medicine, University of Vermont College of Medicine, Burlington, VT, 6Department of Medicine, University of Southern California Keck School of Medicine, Los Angeles, CA, USA Abstract: Erythrodermic psoriasis (EP is a rare and severe variant of psoriasis vulgaris, with an estimated prevalence of 1%–2.25% among psoriatic patients. The condition presents with distinct histopathologic and clinical findings, which include a generalized inflammatory erythema involving at least 75% of the body surface area. The pathogenesis of EP is not well understood; however, several studies suggest that the disease is associated with a predominantly T helper 2 (Th2 phenotype. Given the morbidity and potential mortality associated with the condition, there is a need for a better understanding of its pathophysiology. The management of EP begins with a comprehensive assessment of the patient’s presentation and often requires multidisciplinary supportive measures. In 2010, the medical board of the US National Psoriasis Foundation published consensus guidelines advocating the use of cyclosporine or infliximab as first-line therapy in unstable cases, with acitretin and methotrexate reserved for more stable cases. Since the time of that publication, additional information regarding the efficacy of newer agents has emerged. We review the latest data with regard to the treatment of EP, which includes biologic therapies such as ustekinumab and

  2. Circadian molecular clock in lung pathophysiology.

    Science.gov (United States)

    Sundar, Isaac K; Yao, Hongwei; Sellix, Michael T; Rahman, Irfan

    2015-11-15

    Disrupted daily or circadian rhythms of lung function and inflammatory responses are common features of chronic airway diseases. At the molecular level these circadian rhythms depend on the activity of an autoregulatory feedback loop oscillator of clock gene transcription factors, including the BMAL1:CLOCK activator complex and the repressors PERIOD and CRYPTOCHROME. The key nuclear receptors and transcription factors REV-ERBα and RORα regulate Bmal1 expression and provide stability to the oscillator. Circadian clock dysfunction is implicated in both immune and inflammatory responses to environmental, inflammatory, and infectious agents. Molecular clock function is altered by exposomes, tobacco smoke, lipopolysaccharide, hyperoxia, allergens, bleomycin, as well as bacterial and viral infections. The deacetylase Sirtuin 1 (SIRT1) regulates the timing of the clock through acetylation of BMAL1 and PER2 and controls the clock-dependent functions, which can also be affected by environmental stressors. Environmental agents and redox modulation may alter the levels of REV-ERBα and RORα in lung tissue in association with a heightened DNA damage response, cellular senescence, and inflammation. A reciprocal relationship exists between the molecular clock and immune/inflammatory responses in the lungs. Molecular clock function in lung cells may be used as a biomarker of disease severity and exacerbations or for assessing the efficacy of chronotherapy for disease management. Here, we provide a comprehensive overview of clock-controlled cellular and molecular functions in the lungs and highlight the repercussions of clock disruption on the pathophysiology of chronic airway diseases and their exacerbations. Furthermore, we highlight the potential for the molecular clock as a novel chronopharmacological target for the management of lung pathophysiology.

  3. New Insights into Pathophysiology of Vestibular Migraine

    Science.gov (United States)

    Espinosa-Sanchez, Juan M.; Lopez-Escamez, Jose A.

    2015-01-01

    Vestibular migraine (VM) is a common disorder in which genetic, epigenetic, and environmental factors probably contribute to its development. The pathophysiology of VM is unknown; nevertheless in the last few years, several studies are contributing to understand the neurophysiological pathways involved in VM. The current hypotheses are mostly based on the knowledge of migraine itself. The evidence of trigeminal innervation of the labyrinth vessels and the localization of vasoactive neuropeptides in the perivascular afferent terminals of these trigeminal fibers support the involvement of the trigemino-vascular system. The neurogenic inflammation triggered by activation of the trigeminal-vestibulocochlear reflex, with the subsequent inner ear plasma protein extravasation and the release of inflammatory mediators, can contribute to a sustained activation and sensitization of the trigeminal primary afferent neurons explaining VM symptoms. The reciprocal connections between brainstem vestibular nuclei and the structures that modulate trigeminal nociceptive inputs (rostral ventromedial medulla, ventrolateral periaqueductal gray, locus coeruleus, and nucleus raphe magnus) are critical to understand the pathophysiology of VM. Although cortical spreading depression can affect cortical areas involved in processing vestibular information, functional neuroimaging techniques suggest a dysmodulation in the multimodal sensory integration and processing of vestibular and nociceptive information, resulting from a vestibulo-thalamo-cortical dysfunction, as the pathogenic mechanism underlying VM. The elevated prevalence of VM suggests that multiple functional variants may confer a genetic susceptibility leading to a dysregulation of excitatory–inhibitory balance in brain structures involved in the processing of sensory information, vestibular inputs, and pain. The interactions among several functional and structural neural networks could explain the pathogenic mechanisms of VM

  4. Power-Stepped HF Cross Modulation Experiments at HAARP

    Science.gov (United States)

    Greene, S.; Moore, R. C.; Langston, J. S.

    2013-12-01

    High frequency (HF) cross modulation experiments are a well established means for probing the HF-modified characteristics of the D-region ionosphere. In this paper, we apply experimental observations of HF cross-modulation to the related problem of ELF/VLF wave generation. HF cross-modulation measurements are used to evaluate the efficiency of ionospheric conductivity modulation during power-stepped modulated HF heating experiments. The results are compared to previously published dependencies of ELF/VLF wave amplitude on HF peak power. The experiments were performed during the March 2013 campaign at the High Frequency Active Auroral Research Program (HAARP) Observatory. HAARP was operated in a dual-beam transmission format: the first beam heated the ionosphere using sinusoidal amplitude modulation while the second beam broadcast a series of low-power probe pulses. The peak power of the modulating beam was incremented in 1-dB steps. We compare the minimum and maximum cross-modulation effect and the amplitude of the resulting cross-modulation waveform to the expected power-law dependence of ELF/VLF wave amplitude on HF power.

  5. Eu-doped ZnO-HfO2 hybrid nanocrystal-embedded low-loss glass-ceramic waveguides.

    Science.gov (United States)

    Ghosh, Subhabrata; Bhaktha B N, Shivakiran

    2016-03-11

    We report on the sol-gel fabrication, using a dip-coating technique, of low-loss Eu-doped 70SiO2 -[Formula: see text] HfO2-xZnO (x = 2, 5, 7 and 10 mol%) ternary glass-ceramic planar waveguides. Transmission electron microscopy and grazing incident x-ray diffraction experiments confirm the controlled growth of hybrid nanocrystals with an average size of 3 nm-25 nm, composed of ZnO encapsulated by a thin layer of nanocrystalline HfO2, with an increase of ZnO concentration from x = 2 mol% to 10 mol%  in the SiO2-HfO2 composite matrix. The effect of crystallization on the local environment of Eu ions, doped in the ZnO-HfO2 hybrid nanocrystal-embedded glass-ceramic matrix, is studied using photoluminescence spectra, wherein an intense mixed-valence state (divalent as well as trivalent) emission of Eu ions is observed. The existence of Eu(2+) and Eu(3+) in the SiO2-HfO2-ZnO ternary matrix is confirmed by x-ray photoelectron spectroscopy. Importantly, the Eu[Formula: see text]-doped ternary waveguides exhibit low propagation losses (0.3 ± 0.2 dB cm(-1) at 632.8 nm) and optical transparency in the visible region of the electromagnetic spectrum, which makes ZnO-HfO2 nanocrystal-embedded SiO2-HfO2-ZnO waveguides a viable candidate for the development of on-chip, active, integrated optical devices.

  6. Effects of biological sex on the pathophysiology of the heart

    National Research Council Canada - National Science Library

    Fazal, Loubina; Azibani, Feriel; Vodovar, Nicolas; Cohen Solal, Alain; Delcayre, Claude; Samuel, Jane‐Lise

    2014-01-01

    .... While the effects of biological sex on cardiovascular pathophysiology have long been known, the sex-specific mechanisms mediating these processes have been further elucidated over recent years...

  7. HF dissociation in water clusters by computer simulations

    OpenAIRE

    Elena, Alin Marin

    2013-01-01

    We perform Restrained hybrid Monte Carlo simulations to compute the equilibrium constant of the dissociation reaction of HF in HF(H2O)7. We find that, like in the bulk, hydrofluoric acid, is a weak acid also in the cubic HF(H2O)7 cluster, and that its acidity is higher at lower T. This latter phenomenon has a (vibrational) entropic origin, namely it is due to the reduction of the (negative) T∆S contribution to the variation of free energy between the reactant and product. We found also ...

  8. The effect of Al segregation on Schottky barrier height and effective work function in TiAl/TiN/HfO2 gate stacks

    Science.gov (United States)

    Kim, Geun-Myeong; Oh, Young Jun; Chang, K. J.

    2016-07-01

    We perform first-principles density functional calculations to investigate the effects of Al incorporation on the p-type Schottky barrier height ≤ft({φ\\text{p}}\\right) and the effective work function for various high-k/metal gate stacks, such as TiN/HfO2 with interface Al impurities, Ti1-x Al x N/HfO2, and TiAl/TiN/HfO2. When Al atoms substitute for the interface Ti atoms at TiN/HfO2 interface, interface dipole fields become stronger, leading to the increase of {φ\\text{p}} and thereby the n-type shift of effective work function. In Ti1-x Al x N/HfO2 interface, {φ\\text{p}} linearly increases with the Al content, attributed to the presence of interface Al atoms. On the other hand, in TiAl/TiN/HfO2 interface, where Al is assumed not to segregate from TiAl to TiN, {φ\\text{p}} is nearly independent of the thickness of TiAl. Our results indicate that Al impurities at the metal/dielectric interface play an important role in controlling the effective work function, and provide a clue to understanding the n-type shift of the effective work function observed in TiAl/TiN/HfO2 gate stacks fabricated by using thegate-last process.

  9. Ionospheric heating with oblique HF waves

    Science.gov (United States)

    Field, Edward C., Jr.; Bloom, Ron M.

    1990-10-01

    Calculations of ionospheric electron density perturbations and ground-level signal changes produce by intense oblique high frequency (HF) transmitters are presented. This analysis considers radio field focusing at caustics, the consequent joule-heating of the surrounding plasma, heat conduction, diffusion, and recombination processes: these being the effects of a powerful oblique 'modifying' wave. It neglects whatever plasma instabilities might occur. Then effects on a secondary 'test' wave that is propagated along the same path as the first are investigated. Calculations predict ground-level field-strength reductions of several dB in the test wave for modifying waves having ERP in the 85 to 90 dBW range. These field-strength changes are similar in sign, magnitude, and location to ones measured in Soviet experiments. The results are sensitive to the model ionosphere assumed, so future experiments should employ the widest possible range of frequencies and propagation conditions. An effective power of 90 dBW seems to be a sort of threshold that, if exceeded, results in substantial rather than small signal changes. The conclusions are based solely on joule-heating and subsequent defocusing of waves passing through caustic regions.

  10. Process Simulation Analysis of HF Stripping

    Directory of Open Access Journals (Sweden)

    Thaer A. Abdulla

    2013-05-01

    Full Text Available    HYSYS process simulator is used for the analysis of existing HF stripping column in LAB plant (Arab Detergent Company, Baiji-Iraq. Simulated column performance and profiles curves are constructed. The variables considered are the thermodynamic model option, bottom temperature, feed temperature, and column profiles for the temperature, vapor flow rate, liquid flow rate and composition. The five thermodynamic models options used (Margules, UNIQUAC, van laar, Antoine, and Zudkevitch-Joffee, affecting the results within (0.1-58% variation for the most cases.        The simulated results show that about 4% of paraffin (C10 & C11 presents at the top stream, which may cause a problem in the LAB production plant. The major variations were noticed for the total top vapor flow rate with bottom temperature and with feed composition. The column profiles maintain fairly constants from tray 5 to tray 18. The study gives evidence about a successful simulation with HYSYS because the results correspond with the real plant operation data.

  11. The (178m2) Hf Controversy

    CERN Document Server

    Becker, J A; Schiffer, J P; Wilhelmy, J

    2003-01-01

    Since its discovery in the 1960's the sup 1 sup 7 sup 8 sup m sup 2 Hf isomer has garnered high attention from both the basic and applied communities in nuclear science. It's combination of high spin (16+), long half life (31 yrs), and high excitation energy (2.446 MeV) offer unique possibilities as an energy storage medium. Interest in the isomer was rekindled beginning in 1999 when a series of publications began to appear from a group (referred to here as the ''Texas collaboration'') primarily based at the University of Texas, Dallas [1]. They reported observations that some of the stored energy could be released (''triggered'') when the isomer was exposed to a fluence of photons in the energy range approx 10 to approx 60 keV. The implications of this observation are profound. Even though the claimed cross section for the process was approx 7 orders of magnitude greater than would be predicted from the known systematics of photon absorption by nuclei in this mass range [2], such a highly efficient method fo...

  12. Grindability of cast Ti-Hf alloys.

    Science.gov (United States)

    Kikuchi, Masafumi; Takahashi, Masatoshi; Sato, Hideki; Okuno, Osamu; Nunn, Martha E; Okabe, Toru

    2006-04-01

    As part of our systematic studies characterizing the properties of titanium alloys, we investigated the grindability of a series of cast Ti-Hf alloys. Alloy buttons with hafnium concentrations up to 40 mass% were made using an argon-arc melting furnace. Each button was cast into a magnesia-based mold using a dental titanium casting machine; three specimens were made for each metal. Prior to testing, the hardened surface layer was removed. The specimens were ground at five different speeds for 1 min at 0.98 N using a carborundum wheel on an electric dental handpiece. Grindability was evaluated as the volume of metal removed per minute (grinding rate) and the volume ratio of metal removed compared to the wheel material lost (grinding ratio). The data were analyzed using ANOVA. A trend of increasing grindability was found with increasing amounts of hafnium, although there was no statistical difference in the grindability with increasing hafnium contents. We also found that hafnium may be used to harden or strengthen titanium without deteriorating the grindability.

  13. Development of a novel heart failure risk tool: the barcelona bio-heart failure risk calculator (BCN bio-HF calculator.

    Directory of Open Access Journals (Sweden)

    Josep Lupón

    Full Text Available BACKGROUND: A combination of clinical and routine laboratory data with biomarkers reflecting different pathophysiological pathways may help to refine risk stratification in heart failure (HF. A novel calculator (BCN Bio-HF calculator incorporating N-terminal pro B-type natriuretic peptide (NT-proBNP, a marker of myocardial stretch, high-sensitivity cardiac troponin T (hs-cTnT, a marker of myocyte injury, and high-sensitivity soluble ST2 (ST2, (reflective of myocardial fibrosis and remodeling was developed. METHODS: Model performance was evaluated using discrimination, calibration, and reclassification tools for 1-, 2-, and 3-year mortality. Ten-fold cross-validation with 1000 bootstrapping was used. RESULTS: The BCN Bio-HF calculator was derived from 864 consecutive outpatients (72% men with mean age 68.2 ± 12 years (73%/27% New York Heart Association (NYHA class I-II/III-IV, LVEF 36%, ischemic etiology 52.2% and followed for a median of 3.4 years (305 deaths. After an initial evaluation of 23 variables, eight independent models were developed. The variables included in these models were age, sex, NYHA functional class, left ventricular ejection fraction, serum sodium, estimated glomerular filtration rate, hemoglobin, loop diuretic dose, β-blocker, Angiotensin converting enzyme inhibitor/Angiotensin-2 receptor blocker and statin treatments, and hs-cTnT, ST2, and NT-proBNP levels. The calculator may run with the availability of none, one, two, or the three biomarkers. The calculated risk of death was significantly changed by additive biomarker data. The average C-statistic in cross-validation analysis was 0.79. CONCLUSIONS: A new HF risk-calculator that incorporates available biomarkers reflecting different pathophysiological pathways better allowed individual prediction of death at 1, 2, and 3 years.

  14. The magnetic properties of $^{\\rm 177}$Hf and $^{\\rm 180}$Hf in the strong coupling deformed model

    OpenAIRE

    Muto, S.; Stone, N. J.; Bingham, C. R.; STONE, J.R; Walker, P. M.; Audi, G.; Gaulard, C.; Köster, U.(Institut Laue-Langevin (ILL), Grenoble, France); Nikolov, J.; Nishimura,K; Ohtsubo, T.; Podolyak, Z.; Risegari, L.; Simpson, G.S.; Veskovic, M.

    2014-01-01

    This paper reports NMR measurements of the magnetic dipole moments of two high-K isomers, the 37/2$^-$, 51.4 m, 2740 keV state in $^{\\rm 177}$Hf and the 8$^-$, 5.5 h, 1142 keV state in $^{\\rm 180}$Hf by the method of on-line nuclear orientation. Also included are results on the angular distributions of gamma transitions in the decay of the $^{\\rm 177}$Hf isotope. These yield high precision E2/M1 multipole mixing ratios for transitions in bands built on the 23/2$^+$, 1.1 s, isomer at 1315 keV ...

  15. Missing cells: pathophysiology, diagnosis and management of (pancytopenia in childhood

    Directory of Open Access Journals (Sweden)

    Miriam eErlacher

    2015-07-01

    Full Text Available Peripheral blood cytopenia in children can be due to a variety of acquired or inherited diseases. Genetic disorders affecting a single hematopoietic lineage are frequently characterized by typical bone marrow findings such as lack of progenitors or maturation arrest in congenital neutropenia or a lack of megakaryocytes in congenital amegakaryocytic thrombocytopenia whereas antibody mediated diseases such as autoimmune neutropenia are associated with a rather unremarkable bone marrow morphology. In contrast, pancytopenia is frequently associated with a hypocellular bone marrow and the differential diagnosis includes acquired aplastic anemia, myelodysplastic syndrome, inherited bone marrow failure syndromes such as Fanconi anemia and dyskeratosis congenita and a variety of immunological disorders including hemophagocytic lymphohistiocytosis. Thorough bone marrow analysis is of special importance for the diagnostic work-up of most patients. Cellularity, cellular composition and dysplastic signs are the cornerstones of the differential diagnosis. Pancytopenia in the presence of a normo- or hypercellular marrow with dysplastic changes may indicate myelodysplastic syndrome. More challenging for the hematologist is the evaluation of the hypocellular bone marrow. Although aplastic anemia and hypocellular refractory cytopenia of childhood (RCC can reliably be differentiated on a morphological level the overlapping pathophysiology remains a significant challenge for the choice of the therapeutic strategy. Furthermore, inherited bone marrow failure syndromes are usually associated with the morphological picture of RCC and the recognition of these entities is essential as they often present a multisystem disease requiring different diagnostic and therapeutic approaches. This paper gives an overview over the different disease entities presenting with (pancytopenia, their pathophysiology, characteristic bone marrow findings and therapeutic approaches.

  16. Cortical contributions to the flail leg syndrome: Pathophysiological insights.

    Science.gov (United States)

    Menon, Parvathi; Geevasinga, Nimeshan; Yiannikas, Con; Kiernan, Matthew C; Vucic, Steve

    2016-01-01

    Cortical hyperexcitability has been identified as an intrinsic feature of amyotrophic lateral sclerosis (ALS). Consequently, the aim of the present study was to determine whether cortical hyperexcitability formed the pathophysiological basis for the flail leg syndrome (FL), an atypical ALS variant. Cortical excitability studies were undertaken on 18 FL patients, using the threshold tracking transcranial magnetic stimulation (TMS) technique, and results were compared to healthy controls, upper and lower limb-onset ALS as well as bulbar-onset and the flail arm variant ALS. Results showed that cortical hyperexcitability was a feature of FL and was heralded by a significant reduction of short-interval intracortical inhibition (FL 7.2 ± 1.8%; controls 13.2 ± 0.8%, p <0.01) and cortical silent period (CSP) duration (FL 181.7 ± 10.8ms; controls 209.8 ± 3.4ms; p <0.05) along with an increase in motor evoked potential amplitude (FL 29.2 ± 5.1%; controls 18.9 ± 1.2%, p <0.05). The degree of cortical hyperexcitability was comparable between FL and other ALS phenotypes, defined by site of disease onset. In addition, the CSP duration correlated with biomarkers of peripheral neurodegeneration in FL. In conclusion, cortical hyperexcitability is a feature of the flail leg syndrome, being comparable to other ALS phenotypes. Importantly, cortical hyperexcitability correlates with neurodegeneration, and as such may contribute to the underlying pathophysiology in FL.

  17. A thirty second isomer in {sup 171}Hf

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, P.; Billowes, J.; Cooper, T.G.; Grant, I.S.; Pearson, M.R.; Wheeler, P.D. [Schuster Laboratory, University of Manchester, M13 9PL (United Kingdom); Cochrane, E.C.A.; Cooke, J.L.; Evans, D.E.; Griffith, J.A.R.; Persson, J.R.; Richardson, D.S.; Tungate, G.; Zybert, L. [School of Physics and Space Research, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Dendooven, P.; Honkanen, A.; Huhta, M.; Oinonen, M.; Penttilae, H.; Aeystoe, J. [Accelerator Laboratory, University of Jyvaeskylae, PL 35 Jyvaeskylae SF-403 51 (Finland)

    1997-09-01

    An isomer has been detected in {sup 171}Hf with a half-life of T{sub 1/2} 29.5(9) s. The state was populated in the {sup 170}Yb({alpha},3n){sup 171m}Hf reaction at a beam energy of E{sub {alpha}} = 50 MeV in an on-line ion guide isotope separator. The isomeric {sup 171m}Hf{sup +} beam was extracted from the ion guide, mass-analysed and implanted in the surface of a microchannel-plate. The half-life of the collected activity was measured from the decay of the microchannel-plate count rate. We associate the isomer with the first excited state in {sup 171}Hf with spin 1/2{sup -} at an excitation energy of 22(2) keV. (author)

  18. HF fiber stuffing in building 186 at CERN

    CERN Multimedia

    Tiziano Camporesi

    2003-01-01

    Each of the 36 HF wedges comprise ca 12000 quartz fibers which are the active element of the calorimeter. The fibers are produced by Polymicro (USA), cleaved and bundled at KFKI, Budapest, Hungary and inserted at CERN.

  19. Low-Frequency Waves in HF Heating of the Ionosphere

    Science.gov (United States)

    Sharma, A. S.; Eliasson, B.; Milikh, G. M.; Najmi, A.; Papadopoulos, K.; Shao, X.; Vartanyan, A.

    2016-02-01

    Ionospheric heating experiments have enabled an exploration of the ionosphere as a large-scale natural laboratory for the study of many plasma processes. These experiments inject high-frequency (HF) radio waves using high-power transmitters and an array of ground- and space-based diagnostics. This chapter discusses the excitation and propagation of low-frequency waves in HF heating of the ionosphere. The theoretical aspects and the associated models and simulations, and the results from experiments, mostly from the HAARP facility, are presented together to provide a comprehensive interpretation of the relevant plasma processes. The chapter presents the plasma model of the ionosphere for describing the physical processes during HF heating, the numerical code, and the simulations of the excitation of low-frequency waves by HF heating. It then gives the simulations of the high-latitude ionosphere and mid-latitude ionosphere. The chapter also briefly discusses the role of kinetic processes associated with wave generation.

  20. Near-infrared LIF spectroscopy of HfF

    CERN Document Server

    Grau, Matt; Loh, Huanqian; Sinclair, Laura C; Stutz, Russel P; Yahn, Tylser S; Cornell, Eric A

    2012-01-01

    The molecular ion HfF$^+$ is the chosen species for a JILA experiment to measure the electron electric dipole moment (eEDM). Detailed knowledge of the spectrum of HfF is crucial to prepare HfF$^+$ in a state suitable for performing an eEDM measurement\\cite{Leanhardt}. We investigated the near-infrared electronic spectrum of HfF using laser-induced fluorescence (LIF) of a supersonic molecular beam. We discovered eight unreported bands, and assign each of them unambiguously, four to vibrational bands belonging to the transition $[13.8]0.5 \\leftarrow X1.5$, and four to vibrational bands belonging to the transition $[14.2]1.5 \\leftarrow X1.5$. Additionally, we report an improved measurement of vibrational spacing of the ground state, as well as anharmonicity $\\omega_e x_e$.

  1. Theoretical Assessment of 178m2Hf De-Excitation

    Energy Technology Data Exchange (ETDEWEB)

    Hartouni, E P; Chen, M; Descalle, M A; Escher, J E; Loshak, A; Navratil, P; Ormand, W E; Pruet, J; Thompson, I J; Wang, T F

    2008-10-06

    This document contains a comprehensive literature review in support of the theoretical assessment of the {sup 178m2}Hf de-excitation, as well as a rigorous description of controlled energy release from an isomeric nuclear state.

  2. The effect of adaptive servo ventilation (ASV) on objective and subjective outcomes in Cheyne-Stokes respiration (CSR) with central sleep apnea (CSA) in heart failure (HF): A systematic review.

    Science.gov (United States)

    Yang, Hyunju; Sawyer, Amy M

    2016-01-01

    To summarize the current evidence for adaptive servo ventilation (ASV) in Cheyne-Stokes respiration (CSR) with central sleep apnea (CSA) in heart failure (HF) and advance a research agenda and clinical considerations for ASV-treated CSR-CSA in HF. CSR-CSA in HF is associated with higher overall mortality, worse outcomes and lower quality of life (QOL) than HF without CSR-CSA. Five databases were searched using key words (n = 234). Randomized controlled trials assessed objective sleep quality, cardiac, and self-reported outcomes in adults (≥18 years) with HF (n = 10). ASV has a beneficial effect on the reduction of central sleep apnea in adult patients with CSR-CSA in HF, but it is not be superior to CPAP, bilevel PPV, or supplemental oxygen in terms of sleep quality defined by polysomnography, cardiovascular outcomes, subjective daytime sleepiness, and quality of life. ASV is not recommended for CSR-CSA in HF. It is important to continue to refer HF patients for sleep evaluation to clearly discern OSA from CSR-CSA. Symptom management research, inclusive of objective and subjective outcomes, in CSR-CSA in HF adults is needed.

  3. Different Pathophysiological Phenotypes among Newly Diagnosed Type 2 Diabetes Patients

    DEFF Research Database (Denmark)

    Stidsen, Jacob

    2013-01-01

    Type 2 diabetes (T2D) can be considered a syndrome with several different pathophysiological mechanisms leading to hyperglycemia. Nonetheless, T2D is treated according to algorithms as if it was one disease entity. Methods: We investigated the prevalence of different pathophysiological phenotypes...

  4. Somatosensory dysfunctin in fibromyaligia : Implications for pathophysiological mechanisms

    OpenAIRE

    1996-01-01

    SOMATOSENSORY DYSFUNCTION IN FIBROMYALGIA. IMPLICATIONS FOR PATHOPHYSIOLOGICAL MECHANISMS. Eva KosekDissertation from the Department of Rehabilitation Medicine, Karolinska Institure/Hospital, Stoclcholm, Sweden Fibromyalgia is a chronic pain syndrome characterized by generalized pain, tenderness,disturbed sleep and pronounced fatigue. The pathophysiology is unknown ...

  5. Integrated magnetics design for HF-link power converters

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    This paper deals with the design of integrated magnetics for HF-link converters, where the integrated magnetic components do not necessarily belong to the same voltage loop. Depending on the specific HF-link converter topology, the proposed integrated magnetics can either alleviate the derivation...... of independent auxiliary supply voltages from the main transformer or integrate other magnetic structures, thus saving board space and cutting costs....

  6. Integrated magnetics design for HF-link power converters

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.; Andersen, Michael A.E.

    2005-07-01

    This paper deals with the design of integrated magnetics for HF-link converters, where the two integrated magnetic components on the same core do not necessarily belong to the same voltage loop. Depending on the specific HF-link converter topology, the proposed integrated magnetics can either alleviate the derivation of independent auxiliary supply voltages from the main transformer or integrate other magnetic structures, thus saving board space and cutting costs. (au)

  7. Investigating a TELEmedicine solution to improve MEDication adherence in chronic Heart Failure (TELEMED-HF: study protocol for a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Widdershoven Jos

    2011-10-01

    Full Text Available Abstract Background Frequent rehospitalisations and poorer survival chances in heart failure (HF patients may partly be explained by poor medication adherence. There are multiple medication-related reasons for suboptimal adherence, but psychological reasons may also be important. A novel TELEmonitoring device may improve MEDication adherence in HF patients (TELEMED-HF. TELEMED-HF is a randomized, controlled clinical intervention trial designed to examine (1 the efficacy and cost-efficiency of an electronic medication adherence support system in improving and monitoring HF patients' medication adherence; (2 the effect of medication adherence on hospitalizations and health care consumption; as well as on (3 clinical characteristics, and Quality of Life (QoL; and (4 clinical, sociodemographic, and psychological determinants of medication adherence. Methods/Design Consecutive patients with chronic, systolic HF presenting to the outpatient clinic of the TweeSteden Hospital, The Netherlands, will be approached for study participation and randomly assigned (1:1 following blocked randomization procedures to the intervention (n = 200 or usual care arm (n = 200. Patients in the intervention arm use the medication support device for six months in addition to usual care. Post-intervention, patients return to usual care only and all patients participate in four follow-up occasions over 12 months. Primary endpoints comprise objective and subjective medication adherence, healthcare consumption, number of hospitalizations, and cost-effectiveness. Secondary endpoints include disease severity, physical functioning, and QoL. Discussion The TELEMED-HF study will provide us a comprehensive understanding of medication adherence in HF patients, and will show whether telemonitoring is effective and cost-efficient in improving adherence and preventing hospitalization in HF patients. Trial registration number NCT01347528.

  8. Mechanical, electronic and thermal properties of Cu{sub 5}Zr and Cu{sub 5}Hf by first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Guohui [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Zhang, Xinyu, E-mail: xyzhang@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Qin, Jiaqian, E-mail: jiaqianqin@gmail.com [Metallurgy and Materials Science Research Institute, Chulalongkorn University, Bangkok 10330 (Thailand); Ning, Jinliang; Zhang, Suhong; Ma, Mingzhen; Liu, Riping [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China)

    2015-08-15

    Highlights: • The mechanical and fundamental thermal data of Cu{sub 5}Zr and Cu{sub 5}Hf are determined. • The technologically important elastic anisotropy is obtained and discussed according to its industrial applications. • The brittle/ductile and bonding nature of Cu{sub 5}Zr and Cu{sub 5}Hf are analyzed in details. - Abstract: The structural, elastic, electronic and thermodynamic properties of Cu{sub 5}Zr and Cu{sub 5}Hf compounds are investigated by first-principles calculations combined with the quasi-harmonic Debye model. The calculated lattice parameters of cubic AuBe{sub 5}-type Cu{sub 5}Zr and Cu{sub 5}Hf agree well with available experimental and other theoretical results and the formation enthalpy calculations show that AuBe{sub 5}-type Cu{sub 5}Hf is more energetically stable than the competing hexagonal CaCu{sub 5}-type phase. The mechanical properties such as mechanical stabilities, anisotropy character, ductility (estimated from the value of B/G, Poisson’s ratio υ and Cauchy pressures C{sub 12}–C{sub 44}) and thermodynamic properties such as volume change under temperature and pressure (V/V{sub 0}), heat capacity (C{sub v}), Debye temperature (Θ), thermal expansion coefficient (α) of AuBe{sub 5}-type Cu{sub 5}Zr and Cu{sub 5}Hf are calculated together. Cu{sub 5}Hf has better performances than Cu{sub 5}Zr with higher hardness and better resistance to fracture which are rationalized from the calculated electronic structure (including density of states, charge density distributions, Mulliken’s population analysis) and we find that all ionic, covalent and metallic components exist in bonding of Cu{sub 5}Zr and Cu{sub 5}Hf but the covalent bonding in Cu{sub 5}Hf is stronger.

  9. Senary Refractory High-Entropy Alloy HfNbTaTiVZr

    Science.gov (United States)

    Gao, M. C.; Zhang, B.; Yang, S.; Guo, S. M.

    2016-07-01

    Discovery of new single-phase high-entropy alloys (HEAs) is important to understand HEA formation mechanisms. The present study reports computational design and experimental validation of a senary HEA, HfNbTaTiVZr, in a body-centered cubic structure. The phase diagrams and thermodynamic properties of this senary system were modeled using the CALPHAD method. Its atomic structure and diffusion constants were studied using ab initio molecular dynamics simulations. The microstructure of the as-cast HfNbTaTiVZr alloy was studied using X-ray diffraction and scanning electron microscopy, and the microsegregation in the as-cast state was found to qualitatively agree with the solidification predictions from CALPHAD. Supported by both simulation and experimental results, the HEA formation rules are discussed.

  10. [Vestibular neuronitis: pathophysiology, diagnosis and treatment].

    Science.gov (United States)

    Zaper, Dinka; Adamec, Ivan; Gabelić, Tereza; Krbot, Magdalena; Isgum, Velimir; Hajnsek, Sanja; Habek, Mario

    2012-01-01

    Vestibular neuritis (VN) is one of the most common causes of peripheral vertigo. Caloric testing has been the traditional gold standard for detecting a peripheral vestibular deficit, but some recently developed bedside tests (head thrust, head heave, head shake and vibration test) were evaluated as a good alternative with similar sensitivity and specificity. These tests have shown both diagnostic value in the short term and prognostic value in the long term, and have availability and ease of use as an advantage. As an addition to clinical examination, vestibular evoked myogenic potentials can differentiate between involvement of superior and inferior branch of the vestibular nerve, but also between peripheral and central lesions. Although glucocorticoids are currently widely used in the treatment of VN, there is a lack of evidence for the validity of their administration. There are a number of high quality clinical trials that suggest vestibular rehabilitation exercises, which are based on the mechanisms of vestibular compensation, in the managment of VN. This review will focus on the latest developments in the pathophysiology, diagnosis and treatment of patients with VN.

  11. The Charcot foot: pathophysiology, diagnosis and classification.

    Science.gov (United States)

    Trieb, K

    2016-09-01

    Neuropathic changes in the foot are common with a prevalence of approximately 1%. The diagnosis of neuropathic arthropathy is often delayed in diabetic patients with harmful consequences including amputation. The appropriate diagnosis and treatment can avoid an extensive programme of treatment with significant morbidity for the patient, high costs and delayed surgery. The pathogenesis of a Charcot foot involves repetitive micro-trauma in a foot with impaired sensation and neurovascular changes caused by pathological innervation of the blood vessels. In most cases, changes are due to a combination of both pathophysiological factors. The Charcot foot is triggered by a combination of mechanical, vascular and biological factors which can lead to late diagnosis and incorrect treatment and eventually to destruction of the foot. This review aims to raise awareness of the diagnosis of the Charcot foot (diabetic neuropathic osteoarthropathy and the differential diagnosis, erysipelas, peripheral arterial occlusive disease) and describe the ways in which the diagnosis may be made. The clinical diagnostic pathways based on different classifications are presented. Cite this article: Bone Joint J 2016;98-B:1155-9.

  12. Perimenstrual asthma: from pathophysiology to treatment strategies.

    Science.gov (United States)

    Graziottin, Alessandra; Serafini, Audrey

    2016-01-01

    The prevalence of asthma is about 9,7 % in women and 5,5 % in men. Asthma can deteriorate during the perimenstrual period, a phenomenon known as perimenstrual asthma (PMA), which represents a unique, highly symptomatic asthma phenotype. It is distinguished from traditional allergic asthma by aspirin sensitivity, less atopy, and lower lung capacity. PMA incidence is reported to vary between 19 and 40 % of asthmatic women. The presence of PMA has been related to increases in asthma-related emergency department visits, hospitalizations and emergency treatment including intubations. It is hypothesized that hormonal status may influence asthma in women, focusing on the role of sex hormones, and specifically on the impact of estrogens' fluctuations at ovulation and before periods. This paper will focus on the pathophysiology of hormone triggered cycle related inflammatory/allergic events and their relation with asthma. We reviewed the scientific literature on Pubmed database for studies on PMA. Key word were PMA, mastcells, estrogens, inflammation, oral contraception, hormonal replacement therapy (HRT), and hormone free interval (HFI). Special attention will be devoted to the possibility of reducing the perimenstrual worsening of asthma and associated symptoms by reducing estrogens fluctuations, with appropriate hormonal contraception and reduced HFI. This novel therapeutical approach will be finally discussed.

  13. Pathophysiology and epidemiology of peripartum cardiomyopathy.

    Science.gov (United States)

    Hilfiker-Kleiner, Denise; Sliwa, Karen

    2014-06-01

    Cardiovascular diseases are a major cause of complications in pregnancy worldwide, and the number of patients who develop cardiac problems during pregnancy is increasing. Peripartum cardiomyopathy (PPCM) is a potentially life-threatening heart disease that emerges towards the end of pregnancy or in the first months postpartum, in previously healthy women. Symptoms and signs of PPCM are similar to those in patients with idiopathic dilated cardiomyopathy. The incidence varies geographically, most likely because of socioeconomic and genetic factors. The syndrome is associated with a high morbidity and mortality, and diagnosis is often delayed. Various mechanisms have been investigated, including the hypothesis that unbalanced peripartum or postpartum oxidative stress triggers the proteolytic cleavage of the nursing hormone prolactin into a potent antiangiogenic, proapoptotic, and proinflammatory 16 kDa fragment. This theory provides the basis for the discovery of disease-specific biomarkers and promising novel therapeutic targets. In this Review, we describe the latest understanding of the epidemiology, pathophysiology, and novel treatment strategies for patients with PPCM.

  14. Tinnitus: Network pathophysiology-network pharmacology

    Directory of Open Access Journals (Sweden)

    Ana Belen eElgoyhen

    2012-01-01

    Full Text Available Tinnitus, the phantom perception of sound, is a prevalent disorder. One in 10 adults has clinically significant subjective tinnitus, and for 1 in 100, tinnitus severely affects their quality of life. Despite the significant unmet clinical need for a safe and effective drug targeting tinnitus relief, there is currently not a single FDA-approved drug on the market. The search for drugs that target tinnitus is hampered by the lack of a deep knowledge of the underlying neural substrates of this pathology. Recent studies are increasingly demonstrating that, as described for other central nervous system disorders, tinnitus is a pathology of brain networks. The application of graph theoretical analysis to brain networks has recently provided new information concerning their topology, their robustness and their vulnerability to attacks. Moreover, the philosophy behind drug design and pharmacotherapy in central nervous system pathologies is changing from that of magic bullets that target individual chemoreceptors or disease-causing genes into that of magic shotguns, promiscuous or dirty drugs that target disease-causing networks, also known as network pharmacology. In the present work we provide some insight into how this knowledge could be applied to tinnitus pathophysiology and pharmacotherapy.

  15. Proposed Pathophysiologic Framework to Explain Some ...

    Science.gov (United States)

    The paper proposes a pathophysiologic framework to explain the well-established epidemiological association between exposure to ambient air particle pollution and premature cardiovascular mortality, and offers insights into public health solutions that extend beyond regularory environmental protections to actions that can be taken by individuals, public health officials, healthcare professionals, city and regional planners, local and state governmental officials and all those who possess the capacity to improve cardiovascular health within the popula­tion.The foundation of the framework rests on the contribution of traditional cardiovascular risk factors acting alone and in concert with long-term exposures to air pollutants to create a conditional susceptibility for clinical vascular events, such as myocardial ischemia and infarction; stroke and lethal ventricular arrhythmias. The conceprual framework focuses on the fact that short-term exposures to ambient air particulate matter (PM) are associated with vascular thrombosis (acute coronary syndrome. stroke, deep venous thrombosis. and pulmonary embolism ) and electrical dysfunction (ventricular arrhythmia); and that individuals having prevalent heart disease are at greatest risk. Moreover, exposure is concomitant with changes in autonomic nervous system balance, systemic in­flammation, and prothrombotic/anti-thrombotic and profibrinolytic-antifibrinolytic balance.Thus, a comprehensive solution to the problem o

  16. Orthostatic intolerance: potential pathophysiology and therapy.

    Science.gov (United States)

    Lu, Chih-Cherng; Tseng, Ching-Jiunn; Tang, Hung-Shang; Tung, Che-Se

    2004-09-30

    Orthostatic intolerance affects an estimated 1 in 500 persons and causes a wide range of disabilities. After essential hypertension, it is the most frequently encountered dysautonomia, accounting for the majority of patients referred to centers specializing in autonomic disorders. Patients are typically young females with symptoms such as dizziness, visual changes, head and neck discomfort, poor concentration, fatigue, palpitations, tremulousness, anxiety, and, in some cases, syncope. Syncope is the most hazardous symptom of orthostatic intolerance, presumably occurring because of impaired cerebral perfusion and in part to compensatory autonomic mechanisms. The etiology of this syndrome is still unclear but is heterogeneous. Orthostatic intolerance used to be characterized by an overall enhancement of noradrenergic tone at rest in some patients and by a patchy dysautonomia of postganglionic sympathetic fibers with a compensatory cardiac sympathetic activation in others. However, recent advances in molecular genetics are improving our understanding of orthostatic intolerance, such as several genetic diseases (such as Ehler-Danlos syndrome and norepinephrine transporter deficiency) presenting with symptoms typical of orthostatic intolerance. Future work will include investigation of genetic functional mutations underlying interindividual differences in autonomic cardiovascular control, body fluid regulation, and vascular regulation in orthostatic intolerance patients. The goal of this review article is to describe recent advances in understanding the pathophysiological mechanisms of orthostatic intolerance and their clinical significance.

  17. Pathophysiology and Immune Dysfunction in Endometriosis

    Directory of Open Access Journals (Sweden)

    Soo Hyun Ahn

    2015-01-01

    Full Text Available Endometriosis is an estrogen-dependent, chronic, proinflammatory disease prevalent in 10% of women of reproductive age worldwide. Characterized by the growth of endometrium-like tissue in aberrant locations outside of the uterus, it is responsible for symptoms including chronic pelvic pain, dysmenorrhea, and subfertility that degrade quality of life of women significantly. In Canada, direct and indirect economic cost of endometriosis amounts to 1.8 billion dollars, and this is elevated to 20 billion dollars in the United States. Despite decades of research, the etiology and pathophysiology of endometriosis still remain to be elucidated. This review aims to bring together the current understanding regarding the pathogenesis of endometriosis with specific focus on mechanisms behind vascularization of the lesions and the contribution of immune factors in facilitating lesion establishment and development. The role of hormones, immune cells, and cytokine signaling is highlighted, in addition to discussing the current pharmaceutical options available for management of pain symptoms in women with endometriosis.

  18. Pathophysiology of muscle dysfunction in COPD.

    Science.gov (United States)

    Gea, Joaquim; Agustí, Alvar; Roca, Josep

    2013-05-01

    Muscle dysfunction often occurs in patients with chronic obstructive pulmonary disease (COPD) and may involve both respiratory and locomotor (peripheral) muscles. The loss of strength and/or endurance in the former can lead to ventilatory insufficiency, whereas in the latter it limits exercise capacity and activities of daily life. Muscle dysfunction is the consequence of complex interactions between local and systemic factors, frequently coexisting in COPD patients. Pulmonary hyperinflation along with the increase in work of breathing that occur in COPD appear as the main contributing factors to respiratory muscle dysfunction. By contrast, deconditioning seems to play a key role in peripheral muscle dysfunction. However, additional systemic factors, including tobacco smoking, systemic inflammation, exercise, exacerbations, nutritional and gas exchange abnormalities, anabolic insufficiency, comorbidities and drugs, can also influence the function of both respiratory and peripheral muscles, by inducing modifications in their local microenvironment. Under all these circumstances, protein metabolism imbalance, oxidative stress, inflammatory events, as well as muscle injury may occur, determining the final structure and modulating the function of different muscle groups. Respiratory muscles show signs of injury as well as an increase in several elements involved in aerobic metabolism (proportion of type I fibers, capillary density, and aerobic enzyme activity) whereas limb muscles exhibit a loss of the same elements, injury, and a reduction in fiber size. In the present review we examine the current state of the art of the pathophysiology of muscle dysfunction in COPD.

  19. Hereditary sideroblastic anemias: pathophysiology, diagnosis, and treatment.

    Science.gov (United States)

    Camaschella, Clara

    2009-10-01

    Inherited sideroblastic anemia comprises several rare anemias due to heterogeneous genetic lesions, all characterized by the presence of ringed sideroblasts in the bone marrow. This morphological aspect reflects abnormal mitochondrial iron utilization by the erythroid precursors. The most common X-linked sideroblastic anemia (XLSA), due to mutations of the first enzyme of the heme synthetic pathway, delta-aminolevulinic acid synthase 2 (ALAS2), has linked heme deficiency to mitochondrial iron accumulation. The identification of other genes, such as adenosine triphosphate (ATP) binding cassette B7 (ABCB7) and glutaredoxin 5 (GLRX5), has strengthened the role of iron sulfur cluster biogenesis in sideroblast formation and revealed a complex interplay between pathways of mitochondrial iron utilization and cytosolic iron sensing by the iron-regulatory proteins (IRPs). As recently occurred with the discovery of the SLC25A38-related sideroblastic anemia, the identification of the genes responsible for as yet uncharacterized forms will provide further insights into mitochondrial iron metabolism of erythroid cells and the pathophysiology of sideroblastic anemia.

  20. [Pulmonary rehabilitation: pathophysiology, indications, and clinical efficacy].

    Science.gov (United States)

    Riario Sforza, G G; Incorvaia, C

    2010-01-01

    Pulmonary rehabilitation (PR) is a non pharmacologic treatment of demonstrated efficacy indicated for symptomatic patients with chronic lung diseases. In the pulmonary rehabilitation programs (PRPs), exercise training is a cornerstone component, recommended for improving muscle function. Its aim is to address the disability, intended as the reduction in functional performance and quality of life, derived from muscle deconditioning caused by physical inactivity due to chronic breathlessness, fatigue, and impairment of daily activities claimed by patients with chronic pulmonary diseases. Other components of PRPs are educational, psychosocial and nutritional interventions. Moreover, any PRP should include an outcome assessment, needed for an objective evaluation of program effectiveness, and of patient progress through the time. Although its pivotal role is now accepted worldwide, this was not the prevailing thought during the 1980's and the 1990's, when the pathophysiologic rationale of PR was still not demonstrated, condemning it to be an ancillary treatment to add to standard COPD treatment. The following ascent of PR was mainly due to the number of studies providing its effectiveness, overcoming skepticism and convincing physicians and institutions about its efficacy. Today PR clearly improves exercise tolerance, dyspnea, and quality of life, but despite such demonstration, it is mostly overlooked by health professionals, and only about 2% of patients with COPD undergo to PRPs. A proper consideration of the capability of PR is warranted to ensure optimal management of COPD when the disease causes symptoms and a decrease in physical capacity.

  1. Obesity-related hypertension: possible pathophysiological mechanisms.

    Science.gov (United States)

    Vaněčková, Ivana; Maletínská, Lenka; Behuliak, Michal; Nagelová, Veronika; Zicha, Josef; Kuneš, Jaroslav

    2014-12-01

    Hypertension is one of the major risk factors of cardiovascular diseases, but despite a century of clinical and basic research, the discrete etiology of this disease is still not fully understood. The same is true for obesity, which is recognized as a major global epidemic health problem nowadays. Obesity is associated with an increasing prevalence of the metabolic syndrome, a cluster of risk factors including hypertension, abdominal obesity, dyslipidemia, and hyperglycemia. Epidemiological studies have shown that excess weight gain predicts future development of hypertension, and the relationship between BMI and blood pressure (BP) appears to be almost linear in different populations. There is no doubt that obesity-related hypertension is a multifactorial and polygenic trait, and multiple potential pathogenetic mechanisms probably contribute to the development of higher BP in obese humans. These include hyperinsulinemia, activation of the renin-angiotensin-aldosterone system, sympathetic nervous system stimulation, abnormal levels of certain adipokines such as leptin, or cytokines acting at the vascular endothelial level. Moreover, some genetic and epigenetic mechanisms are also in play. Although the full manifestation of both hypertension and obesity occurs predominantly in adulthood, their roots can be traced back to early ontogeny. The detailed knowledge of alterations occurring in the organism of experimental animals during particular critical periods (developmental windows) could help to solve this phenomenon in humans and might facilitate the age-specific prevention of human obesity-related hypertension. In addition, better understanding of particular pathophysiological mechanisms might be useful in so-called personalized medicine.

  2. In situ isotopic analyses of U and Pb in zircon by remotely operated SHRIMP II, and Hf by LA-ICP-MS: an example of dating and genetic evolution of zircon by {sup 176}Hf/{sup 177}Hf from the Ita Quarry in the Atuba Complex, SE, Brazil; Analises in situ de U e Pb em zircao por SRIMP II por controle remoto e de Hf por LA-ICP-MS: um exemplo de datacao e da evolucao genetica de zircao atraves da razao {sup 176}Hf/{sup 177} em amostra da Pedreira Ita no Complexo Atuba, SE, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Sato, K.; Siga Junior, Oswaldo; McReath, Ian; Sproesser, Walter; Basei, Miguel Angelo Stipp [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias. Centro de Pesquisas Geocronologicas], e-mail: keisato@usp.br, e-mail: osigajr@usp.br, e-mail: ianmcr@usp.br, e-mail: wmspres@usp.br, e-mail: baseimas@usp.br; Silva, Josiane Aline da [Universidade de Sao Paulo (USP), SP (Brazil). Programa de Pos-graduacao em Geoquimica e Geotectonica; Dunyi, Liu [Institute of Geology, Beijing (China); Iizuka, Takafumi; Rino, Shuji; Hirata, Takafumi [Tokyo Institute of Technology, Tokyo (Japan)

    2009-10-15

    Remotely-operated SHRIMP dating of zircon is an interesting alternative for dating of zircon crystals. Although it does not represent any technical progress of the geochronological method using the U-Pb system in zircon it is a very useful and cheap facility. The procedure was first used for mass spectrometric analyses involving two international laboratories in Sao Paulo, Brazil and Beijing, China. It was applied to samples of three gneiss-migmatitic rocks from the Ita quarry in the Atuba Complex (located between the Luis Alves and the Apiai Domain) to test previous controversial hypotheses about its evolution. The presence of important archaean and paleo proterozoic components in the complex is confirmed by analyses of zircon found in probably neo proterozoic leucosomes. Diorite intrusion also occurred during the neo proterozoic, associated with the 0.6Ga continental collisions involved in the assembly of Gondwana. The determination of Hf isotope ratios by LA-ICP/MS represents a new option for checking the relative importance of mantle ({epsilon}{sub Hf} > 0) and crustal contributions (({epsilon}{sub Hf} < 0) during the growth of the zircon crystals. While the archaean component in the complex was derived from the mantle ({epsilon}{sub Hf} + 1.5 to + 8.7) the paleo proterozoic component had a crustal contribution ({epsilon}{sub Hf} - 9.1 to -10.1). (author)

  3. Synthesis of freestanding HfO2 nanostructures

    Directory of Open Access Journals (Sweden)

    Boyle Kayla

    2011-01-01

    Full Text Available Abstract Two new methods for synthesizing nanostructured HfO2 have been developed. The first method entails exposing HfTe2 powders to air. This simple process resulted in the formation of nanometer scale crystallites of HfO2. The second method involved a two-step heating process by which macroscopic, freestanding nanosheets of HfO2 were formed as a byproduct during the synthesis of HfTe2. These highly two-dimensional sheets had side lengths measuring up to several millimeters and were stable enough to be manipulated with tweezers and other instruments. The thickness of the sheets ranged from a few to a few hundred nanometers. The thinnest sheets appeared transparent when viewed in a scanning electron microscope. It was found that the presence of Mn enhanced the formation of HfO2 by exposure to ambient conditions and was necessary for the formation of the large scale nanosheets. These results present new routes to create freestanding nanostructured hafnium dioxide. PACS: 81.07.-b, 61.46.Hk, 68.37.Hk.

  4. Hf impurity and defect interactions in helium-implanted NiHf

    Energy Technology Data Exchange (ETDEWEB)

    Govindaraj, R. E-mail: govind@igcar.ernet.in; Gopinathan, K.P.; Viswanathan, B

    2001-07-01

    TDPAC measurements on the reference and untreated sample indicate a loss in anisotropy which is attributed mainly to the association of probe atoms with defects produced by (n,{gamma}) reactions with isotopes of Ni and experiencing combined magnetic and quadrupole interactions of comparable strengths. Evolution of defect free and substitutional fraction of probe atoms experiencing Larmor frequency characteristic of Ni matrix has been studied as a function of isochronal annealing temperature in helium free {alpha}-irradiated and homogeneously helium-implanted samples. No defect associated Larmor precession frequency and/or quadrupole frequency could be deduced in these uncorrelated damage studies. Comparison of recovery stages in {alpha}-irradiated and helium-implanted samples indicates the binding of helium associated defects by Hf impurities. Segregation of Hf atoms is observed in the helium free {alpha}-irradiated sample for annealing treatment at 973 K, while no such effect is observed in the helium-implanted sample for isochronal annealing treatments up to 1273 K.

  5. Unusual kinetic behavior in cathodic H2 evolution from KF.2HF melts at mild-steel and alloy electrodes

    Directory of Open Access Journals (Sweden)

    Conway Con B.E.

    2004-01-01

    Full Text Available Apart from its interest as a "model" process for kinetic studies of gas-evolving electrode reactions, the cathodic hydrogen evolution reaction (her is involved in several processes that are of importance in applied electrochemistry, e.g., as the cathodic co-reactions in the commercial production of C12 and F2, in electrolyses for production of hydrogen, in electrochemical hydrogenation and, indirectly, as the partial process in corrosion of base metals in the absence of oxygen. The present paper reports several aspects of the unusual behavior of the her that is involved as the co-reaction to electrolytic production of F2 from KF/HF melts using carbon anodes and Fe or mild-steel cathodes. Anomalous anodic polarization behavior that arises in electrolytic generation of F2 from KF/HF melts at carbon electrodes is well known. It is characterized by very high Tafel slopes associated with "CF" film formation and by sluggish F2 bubble disengagement from the electrode. Interest in such effects has, however, tended to overshadow rather similar, so-called "hyper polarization" effects that also arise in the cathodic reaction, but for different reasons. The origins and nature of such effects are described and characterized in the present paper, and comparisons are made between behavior of Hz evolution from KF.2HF and that from the aquo-system analogue, KOH.2H2O. An important aspect is the very different interfacial behavior in KF/HF or KF.2HF melts from that in the corresponding aquo-system. Effects of As-species in HF feeds is investigated in terms of electro catalysis and poisoning effects on the her.

  6. Reconciliation of the excess 176Hf conundrum in meteorites: Recent disturbances of the Lu-Hf and Sm-Nd isotope systematics

    Science.gov (United States)

    Bast, Rebecca; Scherer, Erik E.; Sprung, Peter; Mezger, Klaus; Fischer-Gödde, Mario; Taetz, Stephan; Böhnke, Mischa; Schmid-Beurmann, Hinrich; Münker, Carsten; Kleine, Thorsten; Srinivasan, Gopalan

    2017-09-01

    The long-lived 176Lu-176Hf and 147Sm-143Nd radioisotope systems are commonly used chronometers, but when applied to meteorites, they can reveal disturbances. Specifically, Lu-Hf isochrons commonly yield dates up to ∼300 Myr older than the solar system and varying initial 176Hf/177Hf values. We investigated this problem by attempting to construct mineral and whole rock isochrons for eucrites and angrites. Meteorites from different parent bodies exhibit similar disturbance features suggesting that a common process is responsible. Minerals scatter away from isochron regressions for both meteorite classes, with low-Hf phases such as plagioclase and olivine typically being most displaced above (or left of) reference isochrons. Relatively Hf-rich pyroxene is less disturbed but still to the point of steepening Lu-Hf errorchrons. Using our Lu-Hf and Sm-Nd data, we tested various Hf and Lu redistribution scenarios and found that decoupling of Lu/Hf from 176Hf/177Hf must postdate the accumulation of significant radiogenic 176Hf. Therefore early irradiation or diffusion cannot explain the excess 176Hf. Instead, disturbed meteorite isochrons are more likely caused by terrestrial weathering, contamination, or common laboratory procedures. The partial dissolution of phosphate minerals may predominantly remove rare earth elements including Lu, leaving relatively immobile and radiogenic Hf behind. Robust Lu-Hf (and improved Sm-Nd) meteorite geochronology will require the development of chemical or physical methods for removing unsupported radiogenic Hf and silicate-hosted terrestrial contaminants without disturbing parent-daughter ratios.

  7. Tracking magmatic processes through Zr/Hf ratios in rocks and Hf and Ti zoning in zircons: An example from the Spirit Mountain batholith, Nevada

    Science.gov (United States)

    Lowery, Claiborne L.E.; Miller, C.F.; Walker, B.A.; Wooden, J.L.; Mazdab, F.K.; Bea, F.

    2006-01-01

    Zirconium and Hf are nearly identical geochemically, and therefore most of the crust maintains near-chondritic Zr/Hf ratios of ???35-40. By contrast, many high-silica rhyolites and granites have anomalously low Zr/Hf (15-30). As zircon is the primary reservoir for both Zr and Hf and preferentially incorporates Zr, crystallization of zircon controls Zr/ Hf, imprinting low Zr/Hf on coexisting melt. Thus, low Zr/Hf is a unique fingerprint of effective magmatic fractionation in the crust. Age and compositional zonation in zircons themselves provide a record of the thermal and compositional histories of magmatic systems. High Hf (low Zr/ Hf) in zircon zones demonstrates growth from fractionated melt, and Ti provides an estimate of temperature of crystallization (TTiZ) (Watson and Harrison, 2005). Whole-rock Zr/Hf and zircon zonation in the Spirit Mountain batholith, Nevada, document repeated fractionation and thermal fluctuations. Ratios of Zr/Hf are ???30-40 for cumulates and 18-30 for high-SiO2 granites. In zircons, Hf (and U) are inversely correlated with Ti, and concentrations indicate large fluctuations in melt composition and TTiZ (>100??C) for individual zircons. Such variations are consistent with field relations and ion-probe zircon geochronology that indicate a >1 million year history of repeated replenishment, fractionation, and extraction of melt from crystal mush to form the low Zr/Hf high-SiO2 zone. ?? 2006 The Mineralogical Society.

  8. Determination of isothermal section of Ni-Re-Hf ternary system at 1173 K

    Institute of Scientific and Technical Information of China (English)

    王日初; 柳春雷; 金展鹏

    2002-01-01

    The phase equilibriua in the Ni-Re-Hf ternary system at 1173K were investigated by means of diffusion triple technique and electron microprobe analysis(EMPA). The experimental results indicate that two ternary intermetallics (α and β) and five binary intermetallics (Ni3Hf, Ni10Hf7, Ni11Hf9, NiHf and NiHf2) exist in the Ni-Re-Hf system at 1173 K. A tentative isothermal section of this system at 1173 K was constructed on the basis of experimental results. The isothermal section consists of nine three-phase regions, five of which are supported by the experimental data.

  9. Spallation and fission products in the (p+{sup 179}Hf) and (p+{sup nat}Hf) reactions

    Energy Technology Data Exchange (ETDEWEB)

    Karamian, S.A. [Joint Institute for Nuclear Research, Moscow Region, Dubna 141980 (Russian Federation); Ur, C.A. [Horia Hulubei National Institute of Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest 077125 (Romania); Induced Gamma Emission Foundation, P.O. Box 34-81, Bucharest 010044 (Romania)], E-mail: ur@pd.infn.it; Adam, J. [Joint Institute for Nuclear Research, Moscow Region, Dubna 141980 (Russian Federation); Institute of Nuclear Physics, Rez, Prague CZ-25068 (Czech Republic); Kalinnikov, V.G.; Lebedev, N.A.; Vostokin, G.K. [Joint Institute for Nuclear Research, Moscow Region, Dubna 141980 (Russian Federation); Collins, C.B. [Center for Quantum Electronics, University of Texas at Dallas, Richardson, TX 75083 (United States); Popescu, I.I. [Induced Gamma Emission Foundation, P.O. Box 34-81, Bucharest 010044 (Romania)

    2009-03-01

    Production of Hf and Lu high-spin isomers has been experimentally studied in spallation reactions induced by intermediate energy protons. Targets of enriched {sup 179}Hf (91%) and {sup nat}Hf were bombarded with protons of energy in the range from 90 to 650 MeV provided by the internal beam of the Dubna Phasotron synchrocyclotron. The activation yields of the reaction products were measured by using the {gamma}-ray spectroscopy and radiochemistry methods. The production cross-sections obtained for the {sup 179m2}Hf, {sup 178m2}Hf and {sup 177m}Lu isomers are similar to the previously measured values from the spallation of Ta, Re and W targets. Therefore, the reactions involving emission of only a few nucleons, like (p,p'), (p,p'n) and (p,2pn), can transfer high enough angular momentum to the final residual nuclei with reasonable large cross-sections. A significant gain in the isomeric yields was obtained when enriched {sup 179}Hf targets were used. The mass distribution of the residual nuclei was measured over a wide range of masses and the fission-to-spallation ratio could be deduced as a function of the projectile energy. Features of the reaction mechanism are briefly discussed.

  10. Mechanosensitive TRP channels in cardiovascular pathophysiology.

    Science.gov (United States)

    Inoue, Ryuji; Jian, Zhong; Kawarabayashi, Yasuhiro

    2009-09-01

    Transient receptor potential (TRP) proteins constitute a large non-voltage-gated cation channel superfamily, activated polymodally by various physicochemical stimuli, and are implicated in a variety of cellular functions. Known activators for TRP include not only chemical stimuli such as receptor stimulation, increased acidity and pungent/cooling agents, but temperature change and various forms of mechanical stimuli such as osmotic stress, membrane stretch, and shear force. Recent investigations have revealed that at least ten mammalian TRPs exhibit mechanosensitivity (TRPC1, 5, 6; TRPV1, 2, 4; TRPM3, 7; TRPA1; TRPP2), but the mechanisms underlying it appear considerably divergent and complex. The proposed mechanisms are associated with lipid bilayer mechanics, specialized force-transducing structures, biochemical reactions, membrane trafficking and transcriptional regulation. Many of mechanosensitive (MS)-TRP channel likely undergo multiple regulations via these mechanisms. In the cardiovascular system in which hemodynamic forces constantly operate, the impact of mechanical stress may be particularly significant. Extensive morphological and functional studies have indicated that several MS-TRP channels are expressed in cardiac muscle, vascular smooth muscle, endothelium and vasosensory neurons, each differentially contributing to cardiovascular (CV) functions. To further complexity, the recent evidence suggests that mechanical stress may synergize with neurohormonal mechanisms thereby amplifying otherwise marginal responses. Furthermore, the currently available data suggest that MS-TRP channels may be involved in CV pathophysiology such as cardiac arrhythmia, cardiac hypertrophy/myopathy, hypertension and aneurysms. This review will overview currently known mechanisms for mechanical activation/modulation of TRPs and possible connections of MS-TRP channels to CV disorders.

  11. Leptin in human physiology and pathophysiology.

    Science.gov (United States)

    Mantzoros, Christos S; Magkos, Faidon; Brinkoetter, Mary; Sienkiewicz, Elizabeth; Dardeno, Tina A; Kim, Sang-Yong; Hamnvik, Ole-Petter R; Koniaris, Anastasia

    2011-10-01

    Leptin, discovered through positional cloning 15 years ago, is an adipocyte-secreted hormone with pleiotropic effects in the physiology and pathophysiology of energy homeostasis, endocrinology, and metabolism. Studies in vitro and in animal models highlight the potential for leptin to regulate a number of physiological functions. Available evidence from human studies indicates that leptin has a mainly permissive role, with leptin administration being effective in states of leptin deficiency, less effective in states of leptin adequacy, and largely ineffective in states of leptin excess. Results from interventional studies in humans demonstrate that leptin administration in subjects with congenital complete leptin deficiency or subjects with partial leptin deficiency (subjects with lipoatrophy, congenital or related to HIV infection, and women with hypothalamic amenorrhea) reverses the energy homeostasis and neuroendocrine and metabolic abnormalities associated with these conditions. More specifically, in women with hypothalamic amenorrhea, leptin helps restore abnormalities in hypothalamic-pituitary-peripheral axes including the gonadal, thyroid, growth hormone, and to a lesser extent adrenal axes. Furthermore, leptin results in resumption of menses in the majority of these subjects and, in the long term, may increase bone mineral content and density, especially at the lumbar spine. In patients with congenital or HIV-related lipoatrophy, leptin treatment is also associated with improvements in insulin sensitivity and lipid profile, concomitant with reduced visceral and ectopic fat deposition. In contrast, leptin's effects are largely absent in the obese hyperleptinemic state, probably due to leptin resistance or tolerance. Hence, another emerging area of research pertains to the discovery and/or usefulness of leptin sensitizers. Results from ongoing studies are expected to further increase our understanding of the role of leptin and the potential clinical

  12. Altered Mitochondrial Dynamics and TBI Pathophysiology

    Directory of Open Access Journals (Sweden)

    Tara Diane Fischer

    2016-03-01

    Full Text Available Mitochondrial function is intimately linked to cellular survival, growth, and death. Mitochondria not only generate ATP from oxidative phosphorylation, but also mediate intracellular calcium buffering, generation of reactive oxygen species (ROS, and apoptosis. Electron leakage from the electron transport chain, especially from damaged or depolarized mitochondria, can generate excess free radicals that damage cellular proteins, DNA, and lipids. Furthermore, mitochondrial damage releases pro-apoptotic factors to initiate cell death. Previous studies have reported that traumatic brain injury (TBI reduces mitochondrial respiration, enhances production of ROS, and triggers apoptotic cell death, suggesting a prominent role of mitochondria in TBI pathophysiology. Mitochondria maintain cellular energy homeostasis and health via balanced processes of fusion and fission, continuously dividing and fusing to form an interconnected network throughout the cell. An imbalance of these processes, particularly an excess of fission, can be detrimental to mitochondrial function, causing decreased respiration, ROS production, and apoptosis. Mitochondrial fission is regulated by the cytosolic GTPase, dynamin-related protein 1 (Drp1, which translocates to the mitochondrial outer membrane to initiate fission. Aberrant Drp1 activity has been linked to excessive mitochondrial fission and neurodegeneration. Measurement of Drp1 levels in purified hippocampal mitochondria showed an increase in TBI animals as compared to sham controls. Analysis of cryo-electron micrographs of these mitochondria also showed that TBI caused an initial increase in the length of hippocampal mitochondria at 24 hours post-injury, followed by a significant decrease in length at 72 hours. Post-TBI administration of Mdivi-1, a pharmacological inhibitor of Drp1, prevented this decrease in mitochondria length. Mdivi-1 treatment also reduced the loss of newborn neurons in the hippocampus and improved

  13. Leptin in human physiology and pathophysiology

    Science.gov (United States)

    Magkos, Faidon; Brinkoetter, Mary; Sienkiewicz, Elizabeth; Dardeno, Tina A.; Kim, Sang-Yong; Hamnvik, Ole-Petter R.; Koniaris, Anastasia

    2011-01-01

    Leptin, discovered through positional cloning 15 years ago, is an adipocyte-secreted hormone with pleiotropic effects in the physiology and pathophysiology of energy homeostasis, endocrinology, and metabolism. Studies in vitro and in animal models highlight the potential for leptin to regulate a number of physiological functions. Available evidence from human studies indicates that leptin has a mainly permissive role, with leptin administration being effective in states of leptin deficiency, less effective in states of leptin adequacy, and largely ineffective in states of leptin excess. Results from interventional studies in humans demonstrate that leptin administration in subjects with congenital complete leptin deficiency or subjects with partial leptin deficiency (subjects with lipoatrophy, congenital or related to HIV infection, and women with hypothalamic amenorrhea) reverses the energy homeostasis and neuroendocrine and metabolic abnormalities associated with these conditions. More specifically, in women with hypothalamic amenorrhea, leptin helps restore abnormalities in hypothalamic-pituitary-peripheral axes including the gonadal, thyroid, growth hormone, and to a lesser extent adrenal axes. Furthermore, leptin results in resumption of menses in the majority of these subjects and, in the long term, may increase bone mineral content and density, especially at the lumbar spine. In patients with congenital or HIV-related lipoatrophy, leptin treatment is also associated with improvements in insulin sensitivity and lipid profile, concomitant with reduced visceral and ectopic fat deposition. In contrast, leptin's effects are largely absent in the obese hyperleptinemic state, probably due to leptin resistance or tolerance. Hence, another emerging area of research pertains to the discovery and/or usefulness of leptin sensitizers. Results from ongoing studies are expected to further increase our understanding of the role of leptin and the potential clinical

  14. Altered Mitochondrial Dynamics and TBI Pathophysiology.

    Science.gov (United States)

    Fischer, Tara D; Hylin, Michael J; Zhao, Jing; Moore, Anthony N; Waxham, M Neal; Dash, Pramod K

    2016-01-01

    Mitochondrial function is intimately linked to cellular survival, growth, and death. Mitochondria not only generate ATP from oxidative phosphorylation, but also mediate intracellular calcium buffering, generation of reactive oxygen species (ROS), and apoptosis. Electron leakage from the electron transport chain, especially from damaged or depolarized mitochondria, can generate excess free radicals that damage cellular proteins, DNA, and lipids. Furthermore, mitochondrial damage releases pro-apoptotic factors to initiate cell death. Previous studies have reported that traumatic brain injury (TBI) reduces mitochondrial respiration, enhances production of ROS, and triggers apoptotic cell death, suggesting a prominent role of mitochondria in TBI pathophysiology. Mitochondria maintain cellular energy homeostasis and health via balanced processes of fusion and fission, continuously dividing and fusing to form an interconnected network throughout the cell. An imbalance of these processes, particularly an excess of fission, can be detrimental to mitochondrial function, causing decreased respiration, ROS production, and apoptosis. Mitochondrial fission is regulated by the cytosolic GTPase, dynamin-related protein 1 (Drp1), which translocates to the mitochondrial outer membrane (MOM) to initiate fission. Aberrant Drp1 activity has been linked to excessive mitochondrial fission and neurodegeneration. Measurement of Drp1 levels in purified hippocampal mitochondria showed an increase in TBI animals as compared to sham controls. Analysis of cryo-electron micrographs of these mitochondria also showed that TBI caused an initial increase in the length of hippocampal mitochondria at 24 h post-injury, followed by a significant decrease in length at 72 h. Post-TBI administration of Mitochondrial division inhibitor-1 (Mdivi-1), a pharmacological inhibitor of Drp1, prevented this decrease in mitochondria length. Mdivi-1 treatment also reduced the loss of newborn neurons in the

  15. Mitochondrially mediated plasticity in the pathophysiology and treatment of bipolar disorder.

    Science.gov (United States)

    Quiroz, Jorge A; Gray, Neil A; Kato, Tadafumi; Manji, Husseini K

    2008-10-01

    Bipolar disorder (BPD) has traditionally been conceptualized as a neurochemical disorder, but there is mounting evidence for impairments of cellular plasticity and resilience. Here, we review and synthesize the evidence that critical aspects of mitochondrial function may play an integral role in the pathophysiology and treatment of BPD. Retrospective database searches were performed, including MEDLINE, abstract booklets, and conference proceedings. Articles were also obtained from references therein and personal communications, including original scientific work, reviews, and meta-analyses of the literature. Material regarding the potential role of mitochondrial function included genetic studies, microarray studies, studies of intracellular calcium regulation, neuroimaging studies, postmortem brain studies, and preclinical and clinical studies of cellular plasticity and resilience. We review these data and discuss their implications not only in the context of changing existing conceptualizations regarding the pathophysiology of BPD, but also for the strategic development of improved therapeutics. We have focused on specific aspects of mitochondrial dysfunction that may have major relevance for the pathophysiology and treatment of BPD. Notably, we discuss calcium dysregulation, oxidative phosphorylation abnormalities, and abnormalities in cellular resilience and synaptic plasticity. Accumulating evidence from microarray studies, biochemical studies, neuroimaging, and postmortem brain studies all support the role of mitochondrial dysfunction in the pathophysiology of BPD. We propose that although BPD is not a classic mitochondrial disease, subtle deficits in mitochondrial function likely play an important role in various facets of BPD, and that enhancing mitochondrial function may represent a critical component for the optimal long-term treatment of the disorder.

  16. Hf-Nd isotope and trace element constraints on subduction inputs at island arcs: Limitations of Hf anomalies as sediment input indicators

    Science.gov (United States)

    Handley, Heather K.; Turner, Simon; Macpherson, Colin G.; Gertisser, Ralf; Davidson, Jon P.

    2011-04-01

    New Nd-Hf isotope and trace element data for Javanese volcanoes are combined with recently published data to place constraints on subduction inputs at the Sunda arc in Indonesia and assess the value of Hf anomalies (expressed as Hf/Hf* and Sm/Hf ratios) as tracers of such inputs. Hf anomaly does not correlate with Hf isotope ratio in Javanese lavas, however, Hf/Hf* and Sm/Hf ratios do correlate with SiO 2. Contrary to previous work, we show that Hf anomaly variation may be controlled by fractionation of clinopyroxene and/or amphibole during magmatic differentiation and does not represent the magnitude or type of subduction input in some arcs. Correlation of Sm/Hf with indices of differentiation for other arcs (e.g., Vanuatu, New Britain, and Mariana) suggests that differentiation control on Sm/Hf ratios in volcanic arc rocks may be a relatively common phenomenon. This study corroborates the use of Nd-Hf isotope co-variations in arc volcanic rocks to ascertain subduction input characteristics. The trajectories of regional volcano groups (East, Central and West Java) in Nd-Hf isotope space reveal heterogeneity in the subducted sediment input along Java, which reflects present-day spatial variations in sediment compositions on the down-going plate in the Java Trench. The high Sm/Hf ratio required in the sediment end-member for some Javanese basalts suggests that partial melting of subducted sediment occurs in the presence of residual zircon, and is inconsistent with residual monazite or allanite.

  17. Investigation and Development of Data-Driven D-Region Model for HF Systems Impacts

    Science.gov (United States)

    Eccles, J. V.; Rice, D.; Sojka, J. J.; Hunsucker, R. D.

    2002-01-01

    Space Environment Corporation (SEC) and RP Consultants (RPC) are to develop and validate a weather-capable D region model for making High Frequency (HF) absorption predictions in support of the HF communications and radar communities. The weather-capable model will assimilate solar and earth space observations from NASA satellites. The model will account for solar-induced impacts on HF absorption, including X-rays, Solar Proton Events (SPE's), and auroral precipitation. The work plan includes: I . Optimize D-region model to quickly obtain ion and electron densities for proper HF absorption calculations. 2. Develop indices-driven modules for D-region ionization sources for low, mid, & high latitudes including X-rays, cosmic rays, auroral precipitation, & solar protons. (Note: solar spectrum & auroral modules already exist). 3. Setup low-cost monitors of existing HF beacons and add one single-frequency beacon. 4. Use PENEX HF-link database with HF monitor data to validate D-region/HF absorption model using climatological ionization drivers. 5. Develop algorithms to assimilate NASA satellite data of solar, interplanetary, and auroral observations into ionization source modules. 6. Use PENEX HF-link & HF-beacon data for skill score comparison of assimilation versus climatological D-region/HF absorption model. Only some satellites are available for the PENEX time period, thus, HF-beacon data is necessary. 7. Use HF beacon monitors to develop HF-link data assimilation algorithms for regional improvement to the D-region/HF absorption model.

  18. Serpentinization Changes Nd, but not Hf Isotopes of Abyssal Peridotites

    Science.gov (United States)

    Bizimis, M.; Frisby, C. P.; Mallick, S.

    2015-12-01

    Serpentinization of the oceanic lithosphere is a known sink for fluid mobile elements (B, Cl, Li, Sr, etc.), while high field strength elements (HFSE: e.g., Hf, Zr, Ti, Nb) are thought to be unaffected by it. In contrast, the fate of REE during serpentinization is equivocal. Correlations between REE and HFSE concentrations in abyssal peridotites suggest control by magmatic processes (Niu, 2004, J. Pet), while some LREE enrichments in serpentinized peridotites compared to their clinopyroxene (cpx) and Nd, Sr isotope data (Delacour et al., 2008, Chem. Geol.) imply seawater-derived REE addition to the mantle protolith (Paulick et al., 2006, Chem. Geol). To further constrain peridotite-seawater interaction during serpentinization we compare bulk rock and cpx Hf and Nd isotope data in partially (up to ~70%) serpentinized abyssal peridotites (9-16°E South West Indian Ridge). We also present a new method that improves yields in Hf, Nd and Pb separations from depleted (90% of Hf, Zr, Ti are retained in the residue. LA-ICPMS data shows that serpentine after olivine typically has higher LREE/HREE ratios than cpx, pronounced negative Ce anomalies, high U, Sr concentrations and low HFSE, unlike the coexisting cpx. These data are consistent with some seawater-derived LREE addition to peridotite during serpentinization, localized in the serpentine and other secondary phases, while cpx retains the magmatic value. This process will lower the Sm/Nd relative to Lu/Hf ratio in the peridotite and can lead to decoupled radiogenic Hf and unradiogenic Nd isotopes upon recycling and aging. Our data further testifies to the fidelity of Hf isotopes in tracing mantle processes, even in serpentinized rocks.

  19. Caveolae, lipid droplets, and adipose tissue biology: pathophysiological aspects.

    Science.gov (United States)

    Martin, Sally

    2013-09-01

    Adipocytes are specialized cells that function to store energy in the form of lipids, predominantly triglycerides (TGs), and as a regulatory system contributing to metabolic homoeostasis through the production and secretion of hormones and cytokines. The regulation of lipid homeostasis by adipose tissue is an important aspect of whole-body metabolism. Owing to the central nature of adipose tissue in lipid metabolism, dysregulation has wide-ranging effects, contributing to disorders as diverse as diabetes, cardiovascular disease, cancer, and neurodegeneration. Excess lipids are stored in specialized organelles called lipid droplets (LDs). The surface of the lipid droplet can be considered a highly regulated membrane domain that both protects the contents of the LD from unregulated lipolysis and the cell from the cytotoxic effects of elevated free fatty acids. The surface of the LD is coated with a variety of regulatory proteins, either resident or transiently associated, including enzymes involved in the breakdown of TG, lipid transport proteins, and cofactors. Recent studies have begun to unravel the range of LD-associated proteins and to define their functional significance. Importantly, the involvement of LD proteins in pathophysiological disorders is beginning to be understood. This review will outline recent advances in defining the diversity of LD-associated proteins and their links to metabolic disorders including the integral membrane protein, caveolin-1 (CAV1). Analysis of the role of CAV1 in adipose tissue has highlighted the interconnectedness between the regulation of lipid storage and the function of the adipocyte plasma membrane.

  20. The role of oxidative stress in the pathophysiology of hypertension.

    Science.gov (United States)

    Rodrigo, Ramón; González, Jaime; Paoletto, Fabio

    2011-04-01

    Hypertension is considered to be the most important risk factor in the development of cardiovascular disease. An increasing body of evidence suggests that oxidative stress, which results in an excessive generation of reactive oxygen species (ROS), has a key role in the pathogenesis of hypertension. The modulation of the vasomotor system involves ROS as mediators of vasoconstriction induced by angiotensin II, endothelin-1 and urotensin-II, among others. The bioavailability of nitric oxide (NO), which is a major vasodilator, is highly dependent on the redox status. Under physiological conditions, low concentrations of intracellular ROS have an important role in the normal redox signaling maintaining vascular function and integrity. However, under pathophysiological conditions, increased levels of ROS contribute to vascular dysfunction and remodeling through oxidative damage. In human hypertension, an increase in the production of superoxide anions and hydrogen peroxide, a decrease in NO synthesis and a reduction in antioxidant bioavailability have been observed. In turn, antioxidants are reducing agents that can neutralize these oxidative and otherwise damaging biomolecules. The use of antioxidant vitamins, such as vitamins C and E, has gained considerable interest as protecting agents against vascular endothelial damage. Available data support the role of these vitamins as effective antioxidants that can counteract ROS effects. This review discusses the mechanisms involved in ROS generation, the role of oxidative stress in the pathogenesis of vascular damage in hypertension, and the possible therapeutic strategies that could prevent or treat this disorder.

  1. The pathophysiology of pulmonary hypertension in left heart disease.

    Science.gov (United States)

    Breitling, Siegfried; Ravindran, Krishnan; Goldenberg, Neil M; Kuebler, Wolfgang M

    2015-11-01

    Pulmonary hypertension (PH) is characterized by elevated pulmonary arterial pressure leading to right-sided heart failure and can arise from a wide range of etiologies. The most common cause of PH, termed Group 2 PH, is left-sided heart failure and is commonly known as pulmonary hypertension with left heart disease (PH-LHD). Importantly, while sharing many clinical features with pulmonary arterial hypertension (PAH), PH-LHD differs significantly at the cellular and physiological levels. These fundamental pathophysiological differences largely account for the poor response to PAH therapies experienced by PH-LHD patients. The relatively high prevalence of this disease, coupled with its unique features compared with PAH, signal the importance of an in-depth understanding of the mechanistic details of PH-LHD. The present review will focus on the current state of knowledge regarding the pathomechanisms of PH-LHD, highlighting work carried out both in human trials and in preclinical animal models. Adaptive processes at the alveolocapillary barrier and in the pulmonary circulation, including alterations in alveolar fluid transport, endothelial junctional integrity, and vasoactive mediator secretion will be discussed in detail, highlighting the aspects that impact the response to, and development of, novel therapeutics. Copyright © 2015 the American Physiological Society.

  2. First-principles study of the Hf-based Heusler alloys: Hf2CoGa and Hf2CoIn

    Science.gov (United States)

    Hu, Yan; Zhang, Jian-Min

    2017-01-01

    The electronic structures and magnetic properties of the new Heusler alloys Hf2CoGa and Hf2CoIn have been studied by using the first-principles projector augmented wave (PAW) potential within the generalized gradient approximation (GGA). Both Hf2CoGa and Hf2CoIn Heusler alloys have the half-metallic character and completely (100%) spin polarization at the Fermi level (EF) and the indirect band gaps of 0.733 eV and 0.654 eV, respectively, in the minority spin channel. The total magnetic moments μt are all 2μB per formula unit, linearly scaled with the total number of valence electrons (Zt) by μt=Zt-18 and the atomic magnetic moments have localized character due to less affected by deformations. The origin of the indirect band gaps for these two new Heusler alloys is well understood. These two new Heusler alloys are the ideal candidates for spintronic devices.

  3. In situ simultaneous determination of trace elements,U-Pb and Lu-Hf isotopes in zircon and baddeleyite

    Institute of Scientific and Technical Information of China (English)

    XIE LieWen; ZHANG YanBin; ZHANG HuiHuang; SUN JingFeng; WU FuYuan

    2008-01-01

    This paper describes a combined method of simultaneously measuring U-Pb and Lu-Hf isotopes as well as trace elements in Phalaborwa baddeleyite and 91500, GJ-1, TEMORA-1 and SK10-2 zircons by means of Neptune MC-ICPMS and Agilent Q-ICPMS connected to a 193 nm excimer laser ablation system. Material ablated by laser was carried in different proportions into Q-ICPMS for U-Pb isotopic and trace elemental and MC-ICPMS for Lu-Hf isotopic compositions. Experiments indicate that different propor-tions of ablated material for the Q-ICPMS and MC-ICPMS (6∶4, 5∶5 and 4∶6 respectively) do not show any bias for the zircon/baddeleyite U-Pb age, Lu-Hf isotope and trace elemental compositions within ana-lytical errors. Using 40-60 μm spot size, the obtained U-Pb ages of Phalaborwa baddeleyite, 91500, GJ-1, TEMORA and SK10-2 zircons are 2065~15 (2σ, n=20), 1063±6 (2σ, n=19), 613±6 (2σ,=20), 416±5 (2σ, n=20) and 32.6±0.5 (2σ, n=20) Ma, respectively. The 176Hf/177Hf ratios are 0.281231±24 (2SD, n=20), 0.282310±35 (2SD, n=19), 0.282028±34 (2SD, n=20), 0.282687±34 (2SD, n=20) and 0.282752±53 (2SD, n=20), respectively. The obtained trace elemental compositions are identical to the reference values. Therefore, this kind of technique makes it possible to simultaneously obtain the U-Pb age, Lu-Hf iso-topes and trace elemental compositions of zircon and baddeleyite, which could be an important tool in solving problems in earth sciences.

  4. A short review on the aetiology and pathophysiology of alcoholism

    Directory of Open Access Journals (Sweden)

    Douzenis Athanassios

    2009-05-01

    Full Text Available Abstract Alcoholism is a chronic remitting and relapsing condition; its aetiology and pathophysiology remains largely obscure despite recent advances. This review summarises the current knowledge about the causation (biological or psychological of alcohol addiction. This involves heredity, candidate genes, alcohol metabolism regulation and the influence of alcohol in the pathophysiology of the different neurotransmitter systems. Alcohol addiction is a multifactorial phenomenon where personality structure, individual state of mind and social influences are in constant interaction with brain neurobiology and pathophysiology. This disorder influences different sexes in different ways and causes major problems, especially in developed societies.

  5. Pathophysiology of Pulmonary Hypertension in Chronic Parenchymal Lung Disease.

    Science.gov (United States)

    Singh, Inderjit; Ma, Kevin Cong; Berlin, David Adam

    2016-04-01

    Pulmonary hypertension commonly complicates chronic obstructive pulmonary disease and interstitial lung disease. The association of chronic lung disease and pulmonary hypertension portends a worse prognosis. The pathophysiology of pulmonary hypertension differs in the presence or absence of lung disease. We describe the physiological determinants of the normal pulmonary circulation to better understand the pathophysiological factors implicated in chronic parenchymal lung disease-associated pulmonary hypertension. This review will focus on the pathophysiology of 3 forms of chronic lung disease-associated pulmonary hypertension: idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, and sarcoidosis. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. HF omnidirectional spectral CW auroral radar (HF-OSCAR) at very high latitude. Part 1: Technique

    Science.gov (United States)

    Olesen, J. K.; Jacobsen, K. E.; Stauning, P.; Henriksen, S.

    1983-12-01

    An HF system for studies of very high latitude ionospheric irregularities was described. Radio aurora from field-aligned E-region irregularities of the Slant E Condition type were discussed. The complete system combines an ionosonde, a 12 MHz pulse radar and a 12 MHz bistatic CW Doppler-range set-up. The two latter units use alternately a 360 deg rotating Yagi antenna. High precision oscillators secure the frequency stability of the Doppler system in which the received signal is mixed down to a center frequency of 500 Hz. The Doppler shift range is max + or - 500 Hz. The received signal is recorded in analog form on magnetic tape and may be monitored visually and audibly. Echo range of the CW Doppler signal is obtained by a 150 Hz amplitude modulation of the transmitted signal and phase comparison with the backscattered signal.

  7. Comparison of HfAlO, HfO2/Al2O3, and HfO2 on n-type GaAs using atomic layer deposition

    Science.gov (United States)

    Lu, Bin; Lv, Hongliang; Zhang, Yuming; Zhang, Yimen; Liu, Chen

    2016-11-01

    Different high-permittivity (high-k) gate dielectric structures of HfO2, HfAlO, and HfO2/Al2O3 deposited on HF-etched n-GaAs using ALD have been investigated. It has been demonstrated that the stacked structure of HfO2/Al2O3 has the lowest interface state density of 8.12 × 1012eV-1 cm-2 due to the "self-cleaning" reaction process, but the sample of HfAlO shows much better frequency dispersion and much higher dielectric permittivity extracted from the C-V curves. The investigation reveals that the electrical properties of gate dielectrics are improved by introducing alumina into HfO2.

  8. Mechanical properties of cast Ti-Hf alloys.

    Science.gov (United States)

    Sato, Hideki; Kikuchi, Masafumi; Komatsu, Masashi; Okuno, Osamu; Okabe, Toru

    2005-02-15

    This study examined the mechanical properties of a series of Ti-Hf alloys. Titanium alloys with 10 to 40 mass % Hf were made with titanium and hafnium sponge in an argon-arc melting furnace. Specimens cast into magnesia-based investment molds were tested for yield strength, tensile strength, percentage elongation, and modulus of elasticity. Vickers microhardness was determined at 25 to 600 microm from the cast surface. X-ray diffractometry was also performed. Commercially pure Ti (CP Ti) and pure Ti prepared from titanium sponge were used as controls. The data (n = 5) were analyzed with a one-way ANOVA and the Student-Newman-Keuls test (alpha = 0.05). The diffraction peaks of all the metals matched those for alpha Ti; no beta phase peaks were found. Alloys with Hf > or = 25% had significantly (p 0.05) in elongation among all the Ti-Hf alloys and CP Ti, whereas the elongation of alloys with Hf > or = 30% was significantly (p alloys tested can be considered viable alternatives to CP Ti because they were stronger than CP Ti and had similar elongation.

  9. DMPD: Pathophysiological roles of interleukin-18 in inflammatory liver diseases. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 10807517 Pathophysiological roles of interleukin-18 in inflammatory liver diseases....l) Show Pathophysiological roles of interleukin-18 in inflammatory liver diseases. PubmedID 10807517 Title Pathophysiological role

  10. Hypertension and obesity after pediatric kidney transplantation: management based on pathophysiology: A mini review

    Directory of Open Access Journals (Sweden)

    Eunice G John

    2014-01-01

    Full Text Available Hypertension after pediatric renal transplant is a common and important risk factor for graft loss and patient survival. The mechanism of post kidney transplant hypertension is complex and multifactorial. Control of blood pressure in renal transplant patients is important but often times blood pressures remain uncontrolled. The management of hypertension and obesity in pediatric kidney transplant patients is based on the pathophysiology. Compared to the general pediatric hypertensive population, special attention needs to be focused on the additional impact of immunosuppressive medications side effects and interactions, recurrent disease, and donor and recipient comorbidities such as obesity on blood pressure control with thoughtful consideration of the risk of graft failure. In general, there is a need for prospective studies in pediatric kidney transplant patients to understand the pathophysiology of hypertension and obesity and the appropriate approach to achieve a balance between the primary need to avoid rejection and the need to lower blood pressure and prevent obesity.

  11. Pathophysiology of the cysteinyl leukotrienes and effects of leukotriene receptor antagonists in asthma

    DEFF Research Database (Denmark)

    Bisgaard, H

    2001-01-01

    Cysteinyl leukotrienes, synthesized de novo from cell membrane phospholipids, are proinflammatory mediators that play an important role in the pathophysiology of asthma. These mediators are among the most potent of bronchoconstrictors and cause vasodilation, increased microvascular permeability, ...... antagonists are additive with those of beta agonists. These data provide strong support for the use of leukotriene receptor antagonists for treating asthma.......Cysteinyl leukotrienes, synthesized de novo from cell membrane phospholipids, are proinflammatory mediators that play an important role in the pathophysiology of asthma. These mediators are among the most potent of bronchoconstrictors and cause vasodilation, increased microvascular permeability...... ciliary motility, which may hinder mucociliary clearance. Asthmatic patients demonstrate increased production of cysteinyl leukotrienes during naturally occurring asthma and acute asthma attacks as well as after allergen and exercise challenge. The leukotriene receptor antagonists montelukast, zafirlukast...

  12. The role of stress in heart failure – ground for sex specific pathophysiology

    Directory of Open Access Journals (Sweden)

    Viljetic B.

    2011-04-01

    Full Text Available In the last hundred years modern society went through numerous changes in life style, dietary habits, work load, physical activity and other environmental factors. As a species we are not well adapted to new de- mands. Higher levels of stress hormones provoke various effects, especially gradual change in the sensitivity of adrenergic, glucocorticoid and insulin receptors. All these changes are mutually associated and they gradually lead to metabolic syndrome, obesity, diabetes, heart failure and other types of pathology depending on genetic makeup and environmental factors. The aim of this paper is to summarize current knowledge concerning the impact of stress on cardiac function. Whereas stress response is sex specific we would emphasize a potential difference in pathophysiology of ischemic heart failure in men and women. Modern medicine has misinterpreted autonomous nervous system functions for years and this was reflected in heart failure (HF and arterial hypertension therapy. Stress before the onset of menopause has a lesser effect on cardiac function compared to stress after menopause. Postmenopausal women have a significantly higher risk of heart disease, which is related to the diminished protection of the female hormonal cycle, but low doses of estrogen have not proven protective in postmenopausal women. Potential new targets of sex- specific cardiac therapy would come from better understanding of the molecular mechanisms exerted by nuclear receptors for steroid hormones, transcription factors involved in heart remodeling, cross-talk in adrenergic signaling pathways and their down-stream molecules.

  13. Pathophysiology of shunt dysfunction in shunt treated hydrocephalus

    DEFF Research Database (Denmark)

    Blegvad, C.; Skjolding, A D; Broholm, H

    2013-01-01

    We hypothesized that shunt dysfunction in the ventricular catheter and the shunt valve is caused by different cellular responses. We also hypothesized that the cellular responses depend on different pathophysiological mechanisms....

  14. Delirium in Critically Ill Patients Epidemiology, Pathophysiology, Diagnosis and Management

    NARCIS (Netherlands)

    Zaal, Irene J.; Slooter, Arjen J. C.

    2012-01-01

    Delirium is commonly observed in critically ill patients and is associated with negative outcomes. The pathophysiology of delirium is not completely understood. However, alterations to neurotransmitters, especially acetylcholine and dopamine, inflammatory pathways and an aberrant stress response are

  15. Visceral hypersensitivity in Irritable Bowel Syndrome:pathophysiological mechanisms

    NARCIS (Netherlands)

    Kerckhoffs, A.P.M.

    2009-01-01

    Irritable Bowel Syndrome (IBS) is a functional bowel disease characterized by abdominal pain or discomfort associated with a disordered defecation. No unique pathophysiological mechanism has been identified. It is most likely a multifactorial disease involving alterations in intestinal microbiota

  16. HfO2 Gate Dielectrics for Future Generation of CMOS Device Application

    Institute of Scientific and Technical Information of China (English)

    H.Y.Yu; J.F.Kang; Ren Chi; M.F.Li; D.L.Kwong

    2004-01-01

    The material and electrical properties of HfO2 high-k gate dielectric are reported.In the first part,the band alignment of HfO2 and (HfO2)x(Al2O3)1-x to (100)Si substrate and their thermal stability are studied by X-ray photoelectron spectroscopy and TEM.The energy gap of (HfO2)x(Al2O3)1-x,the valence band offset,and the conduction band offset between (HfO2)x(Al2O3)1-x and the Si substrate as functions of x are obtained based on the XPS results.Our XPS results also demonstrate that both the thermal stability and the resistance to oxygen diffusion of HfO2 are improved by adding Al to form Hf aluminates.In the second part,a thermally stable and high quality HfN/HfO2 gate stack is reported.Negligible changes in equivalent oxide thickness (EOT),gate leakage,and work function (close to Si mid-gap) of HfN/HfO2 gate stack are demonstrated even after 1000℃ post-metal annealing(PMA),which is attributed to the superior oxygen diffusion barrier of HfN as well as the thermal stability of the HfN/HfO2 interface.Therefore,even without surface nitridation prior to HfO2 deposition,the EOT of HfN/HfO2 gate stack has been successfully scaled down to less than 1nm after 1000℃ PMA with excellent leakage and long-term reliability.The last part demonstrates a novel replacement gate process employing a HfN dummy gate and sub-1nm EOT HfO2 gate dielectric.The excellent thermal stability of the HfN/HfO2 gate stack enables its use in high temperature CMOS processes.The replacement of HfN with other metal gate materials with work functions adequate for n- and p-MOS is facilitated by a high etch selectivity of HfN with respect to HfO2,without any degradation to the EOT,gate leakage,or TDDB characteristics of HfO2.

  17. Pressure-induced novel compounds in the Hf-O system from first-principles calculations

    Science.gov (United States)

    Zhang, Jin; Oganov, Artem R.; Li, Xinfeng; Xue, Kan-Hao; Wang, Zhenhai; Dong, Huafeng

    2015-11-01

    Using first-principles evolutionary simulations, we have systematically investigated phase stability in the Hf-O system at pressure up to 120 GPa. New compounds Hf5O2,Hf3O2 , HfO, and HfO3 are discovered to be thermodynamically stable at certain pressure ranges. Two new high-pressure phases are found for Hf2O : one with space group Pnnm and anti-CaCl2-type structure, another with space group I 41/amd. Pnnm-HfO3 shows interesting structure, simultaneously containing oxide O2 - and peroxide [O-O]2 - anions. Remarkably, it is P 6 ¯2 m -HfO rather than OII-HfO2 that exhibits the highest mechanical characteristics among Hf-O compounds. Pnnm-Hf2O , Imm2-Hf5O2 ,P 3 ¯1 m -Hf2O , and P 4 ¯m 2 -Hf2O3 phases also show superior mechanical properties; theoretically these phases become metastable phases to ambient pressure and their properties can be exploited.

  18. Pathophysiology of reversible sudden deafness--epidemiological study.

    OpenAIRE

    Ohsaki, Katsuichiro; Aoyama, Hideyasu

    1983-01-01

    Many aspects of the etiology and pathophysiology of reversible sudden deafness remain obscure. In order to better understand the pathophysiology of reversible sudden deafness we compared the results of two therapies which have different mechanisms of action. The results of therapy with tranexamic acid alone in 49 cases (57 ears) of sudden deafness were compared with the results of treatment with so-called antisludging agents in 65 cases (69 ears) using the chi square contingency test. The sam...

  19. Adaptive Immune Responses Regulate the Pathophysiology of Lymphedema

    Science.gov (United States)

    2012-09-01

    Pathophysiology of Lymphedema PRINCIPAL INVESTIGATOR: Jamie Zampell, M.D. CONTRACTING ORGANIZATION: Sloan-Kettering Institute for...Immune Responses Regulate the Pathophysiology of Lymphedema 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-11-1-0495 5c. PROGRAM ELEMENT... Lymphedema is a debilitating disorder affecting as many as 1 in 8 cancer survivors. Despite wide prevalence, limited understanding of disease

  20. Teaching pathophysiology: strategies to enliven the traditional lecture.

    Science.gov (United States)

    Van Horn, Elizabeth R; Hyde, Yolanda M; Tesh, Anita S; Kautz, Donald D

    2014-01-01

    The depth and breadth of pathophysiology content, foundational for nursing practice, is well suited for traditional lecture delivery. Use of creative strategies can deepen students' understanding while respecting students' diverse talents and ways of learning. The authors discuss strategies they used, including case studies, questions asked during lecture using immediate feedback technology, creative visual demonstrations, group pathophysiologic theory projects, short videos, and games, to enhance students' understanding and retention of content.

  1. Major Pathophysiological Correlations of Rosacea: A Complete Clinical Appraisal

    OpenAIRE

    Vemuri, Ravi Chandra; Gundamaraju, Rohit; Sekaran, Shamala Devi; Manikam, Rishya

    2015-01-01

    Background: Rosacea is a characteristic cutaneous disorder with a diverse clinical manifestations ranging from facial vascular hyper-reactivity to sebaceous gland hyperplasia. Many theories on pathophysiology of rosacea were proposed over the past decade, however the pathogenicity is poorly understood. Aim: To review the evidence on different pathophysiological correlations of rosacea. Methods: A literature search was conducted for studies published between 1990 to March 2014. The inclusion c...

  2. Pathophysiology of acute small bowel disease with CT correlation

    Energy Technology Data Exchange (ETDEWEB)

    Sarwani, N., E-mail: nsarwani@hmc.psu.ed [Department of Radiology, Section of Abdominal Imaging, Penn State Milton Hershey Medical Center, Hershey, PA (United States); Tappouni, R.; Tice, J. [Department of Radiology, Section of Abdominal Imaging, Penn State Milton Hershey Medical Center, Hershey, PA (United States)

    2011-01-15

    The objective of this article is to review the pathophysiology of acute small bowel diseases, and to correlate the mechanisms of disease with computed tomography (CT) findings. Disease entities will be classified into the following: immune mediated and infectious causes, vascular causes, mechanical causes, trauma, and others. Having an understanding of acute small bowel pathophysiology is a useful teaching tool, and can lead to imaging clues to the most likely diagnosis of acute small bowel disorders.

  3. Pathophysiology of reversible sudden deafness--epidemiological study.

    OpenAIRE

    Ohsaki, Katsuichiro; Aoyama, Hideyasu

    1983-01-01

    Many aspects of the etiology and pathophysiology of reversible sudden deafness remain obscure. In order to better understand the pathophysiology of reversible sudden deafness we compared the results of two therapies which have different mechanisms of action. The results of therapy with tranexamic acid alone in 49 cases (57 ears) of sudden deafness were compared with the results of treatment with so-called antisludging agents in 65 cases (69 ears) using the chi square contingency test. The sam...

  4. Band alignment and interfacial chemical structure of the HfLaO/InGaZnO4 heterojunction investigated by x-ray photoelectron spectroscopy

    Science.gov (United States)

    Qian, Ling-Xuan; Wu, Ze-Han; Zhang, Yi-Yu; Liu, Yuan; Song, Jia-Qi; Liu, Xing-Zhao; Li, Yan-Rong

    2017-04-01

    Amorphous InGaZnO4 thin film transistors (a-IGZO TFTs) with HfLaO gate dielectrics have been widely demonstrated to possess extremely excellent electrical characteristics, and thus show great potential for applications in various next-generation electronic products. Nevertheless, the in-depth understanding of HfLaO/IGZO interfacial features is still lacking, which makes further device optimization lack clear guidance. In this work, the band alignment and interfacial chemical structure of a sputtering-prepared HfLaO/IGZO heterojunction was investigated through x-ray photoelectron spectroscopy. The valence and conduction band offsets (ΔE v and ΔE c) at the interface were determined to be 0.57 eV and 1.48 eV, respectively. The relatively large ΔE v is mainly attributed to the formation of the interfacial layer (IL) and thus the upward band bending from IGZO to the surface of HfLaO. Furthermore, it was found that the oxygen vacancies on the surface of IGZO were significantly suppressed upon the deposition of HfLaO, which not only explained the previously reported ultrahigh performance of a-IGZO/HfLaO TFTs to some extent, but also additionally validated the formation of the IL. Our findings have successfully revealed the importance of ILs in modifying the band alignment and interfacial trap states of HfLaO/IGZO heterojunctions, thus suggesting a potential route to further optimizing a-IGZO/HfLaO TFTs so as to satisfy the requirements of next-generation technologies.

  5. SnO2 anode surface passivation by atomic layer deposited HfO2 improves li-ion battery performance

    KAUST Repository

    Yesibolati, Nulati

    2014-03-14

    For the first time, it is demonstrated that nanoscale HfO2 surface passivation layers formed by atomic layer deposition (ALD) significantly improve the performance of Li ion batteries with SnO2-based anodes. Specifically, the measured battery capacity at a current density of 150 mAg -1 after 100 cycles is 548 and 853 mAhg-1 for the uncoated and HfO2-coated anodes, respectively. Material analysis reveals that the HfO2 layers are amorphous in nature and conformably coat the SnO2-based anodes. In addition, the analysis reveals that ALD HfO2 not only protects the SnO2-based anodes from irreversible reactions with the electrolyte and buffers its volume change, but also chemically interacts with the SnO2 anodes to increase battery capacity, despite the fact that HfO2 is itself electrochemically inactive. The amorphous nature of HfO2 is an important factor in explaining its behavior, as it still allows sufficient Li diffusion for an efficient anode lithiation/delithiation process to occur, leading to higher battery capacity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Effect of HF leaching on 14C dates of pottery

    Science.gov (United States)

    Goslar, Tomasz; Kozłowski, Janusz; Szmyt, Marzena; Czernik, Justyna

    2013-01-01

    This paper presents the experiments with 14C dating of two potsherds, which contained carbon dispersed rather homogeneously in their clay fabric. After AAA treatment, the potsherds still appeared to be contaminated with young carbon, presumably connected with humic acids. To make removal of humic acids more effective, we treated the sherds with HF acid of different concentration. The 14C results obtained demonstrate that HF treatment indeed helps to remove humic contaminants, but it also mobilizes carbon bound to raw clay, which may make 14C dates too old. We conclude therefore, that using a simple combination of HF and AAA treatment seems insufficient in reliable 14C dating of carbon homogeneously dispersed in the volume of potsherds.

  7. Autonomic Nervous System in Viral Myocarditis: Pathophysiology and Therapy.

    Science.gov (United States)

    Cheng, Zheng; Li-Sha, Ge; Yue-Chun, Li

    2016-01-01

    Myocarditis, which is caused by viral infection, can lead to heart failure, malignant arrhythmias, and even sudden cardiac death in young patients. It is also one of the most important causes of dilated cardiomyopathy worldwide. Although remarkable advances in diagnosis and understanding of pathophysiological mechanisms of viral myocarditis have been gained during recent years, no standard treatment strategies have been defined as yet. Fortunately, recent studies present some evidence that immunomodulating therapy is effective for myocarditis. The immunomodulatory effect of the autonomic nervous system has raised considerable interest over recent decades. Studying the influence on the inflammation and immune system of the sympathetic and parasympathetic nervous systems will not only increase our understanding of the mechanism of disease but could also lead to the identification of potential new therapies for viral myocarditis. Studies have shown that the immunomodulating effect of the sympathetic and parasympathetic nervous system is realized by the release of neurotransmitters to their corresponding receptors (catecholamine for α or β adrenergic receptor, acetylcholine for α7 nicotinic acetylcholinergic receptor). This review will discuss the current knowledge of the roles of both the sympathetic and parasympathetic nervous system in inflammation, with a special focus on their roles in viral myocarditis.

  8. The role of platelets in the pathophysiology of asthma.

    Science.gov (United States)

    Kornerup, K N; Page, C P

    2007-08-01

    The incidence of asthma is on the increase worldwide, yet the pathogenesis of this disease is still not fully understood. Many recent drug trials have had disappointing results, thus fuelling the need for more research to be undertaken in this area. Substantial evidence suggests an important role for platelets in various inflammatory diseases, including atherosclerosis, rheumatoid arthritis, eczema, allergic rhinitis and asthma. In asthma, platelets have been found to actively participate in most of its main features, including bronchial hyperresponsiveness, bronchoconstriction, airway inflammation and airway remodelling. It has recently become clear that platelet-release products, as well as the expression of adhesion molecules on the platelet surface and the ability to undergo chemotaxis, are all involved in these processes. This review focuses on both experimental and clinical studies available to date that have investigated the role of platelets in the pathophysiology of asthma. Taken together, the evidence points toward platelets being an attractive new target in the area of asthma research; a target with much-needed novel therapeutic potential.

  9. Genetics of liver disease: From pathophysiology to clinical practice.

    Science.gov (United States)

    Karlsen, Tom H; Lammert, Frank; Thompson, Richard J

    2015-04-01

    Paralleling the first 30 years of the Journal of Hepatology we have witnessed huge advances in our understanding of liver disease and physiology. Genetic advances have played no small part in that. Initial studies in the 1970s and 1980s identified the strong major histocompatibility complex associations in autoimmune liver diseases. During the 1990 s, developments in genomic technologies drove the identification of genes responsible for Mendelian liver diseases. Over the last decade, genome-wide association studies have allowed for the dissection of the genetic susceptibility to complex liver disorders, in which also environmental co-factors play important roles. Findings have allowed the identification and elaboration of pathophysiological processes, have indicated the need for reclassification of liver diseases and have already pointed to new disease treatments. In the immediate future genetics will allow further stratification of liver diseases and contribute to personalized medicine. Challenges exist with regard to clinical implementation of rapidly developing technologies and interpretation of the wealth of accumulating genetic data. The historical perspective of genetics in liver diseases illustrates the opportunities for future research and clinical care of our patients.

  10. Proton production, regulation and pathophysiological roles in the mammalian brain

    Institute of Scientific and Technical Information of China (English)

    Wei-Zheng Zeng; Tian-Le Xu

    2012-01-01

    The recent demonstration of proton signaling in C elegans muscle contraction suggests a novel mechanism for proton-based intercellular communication and has stimulated enthusiasm for exploring proton signaling in higher organisms.Emerging evidence indicates that protons are produced and regulated in localized space and time.Furthermore,identification of proton regulators and sensors in the brain leads to the speculation that proton production and regulation may be of major importance for both physiological and pathological functions ranging from nociception to learning and memory.Extracellular protons may play a role in signal transmission by not only acting on adjacent cells but also affecting the cell from which they were released.In this review,we summarize the upstream and downstream pathways of proton production and regulation in the mammalian brain,with special emphasis on the proton extruders and sensors that are critical in the homeostatic regulation of pH,and discuss their potential roles in proton signaling under normal and pathophysiological conditions.

  11. Neurotrophin signalling: novel insights into mechanisms and pathophysiology

    Science.gov (United States)

    Mitre, Mariela; Mariga, Abigail; Chao, Moses V.

    2017-01-01

    Neurotrophins, such as brain-derived neurotrophic factor (BDNF), are prominent regulators of neuronal survival, growth and differentiation during development. While trophic factors are viewed as well-understood but not innovative molecules, there are many lines of evidence indicating that BDNF plays an important role in the pathophysiology of many neurodegenerative disorders, depression, anxiety and other psychiatric disorders. In particular, lower levels of BDNF are associated with the aetiology of Alzheimer’s and Huntington’s diseases. A major challenge is to explain how neurotrophins are able to induce plasticity, improve learning and memory and prevent age-dependent cognitive decline through receptor signalling. This article will review the mechanism of action of neurotrophins and how BDNF/tropomyosin receptor kinase B (TrkB) receptor signaling can dictate trophic responses and change brain plasticity through activity-dependent stimulation. Alternative approaches for modulating BDNF/TrkB signalling to deliver relevant clinical outcomes in neurodegenerative and neuropsychiatric disorders will also be described. PMID:27908981

  12. The pathophysiology of hypertension in systemic lupus erythematosus.

    Science.gov (United States)

    Ryan, Michael J

    2009-04-01

    Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disorder that predominantly affects women during their reproductive years. Although SLE can affect any organ system, the kidneys are prominently involved in the form of immune complex glomerulonephritis. In addition, in women with SLE, risk for the development of cardiovascular disease is dramatically increased. Hypertension is a major risk factor for cardiovascular disease and is highly prevalent in women with SLE. Nevertheless, there has been little exploration of the pathophysiological mechanisms that promote SLE hypertension. This review discusses the role of several mechanisms, with an emphasis on the kidney, in SLE hypertension. These mechanisms include the renin-angiotensin system, endothelin, oxidative stress, sex steroids, metabolic changes, peroxisome proliferator-activated receptor-gamma, and, perhaps most importantly, chronic inflammation and cytokines. Growing evidence suggests a link between chronic inflammation and hypertension. Therefore, elucidation of mechanisms that promote SLE hypertension may be of significant value not only for patients with SLE, but also for a better understanding of the basis for essential hypertension.

  13. Hypertension in children with chronic kidney disease: pathophysiology and management.

    Science.gov (United States)

    Hadtstein, Charlotte; Schaefer, Franz

    2008-03-01

    Arterial hypertension is very common in children with all stages of chronic kidney disease (CKD). While fluid overload and activation of the renin-angiotensin system have long been recognized as crucial pathophysiological pathways, sympathetic hyperactivation, endothelial dysfunction and chronic hyperparathyroidism have more recently been identified as important factors contributing to CKD-associated hypertension. Moreover, several drugs commonly administered in CKD, such as erythropoietin, glucocorticoids and cyclosporine A, independently raise blood pressure in a dose-dependent fashion. Because of the deleterious consequences of hypertension on the progression of renal disease and cardiovascular outcomes, an active screening approach should be adapted in patients with all stages of CKD. Before one starts antihypertensive treatment, non-pharmacological options should be explored. In hemodialysis patients a low salt diet, low dialysate sodium and stricter dialysis towards dry weight can often achieve adequate blood pressure control. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers are first-line therapy for patients with proteinuria, due to their additional anti-proteinuric properties. Diuretics are a useful alternative for non-proteinuric patients or as an add-on to renin-angiotensin system blockade. Multiple drug therapy is often needed to maintain blood pressure below the 90th percentile target, but adequate blood pressure control is essential for better renal and cardiovascular long-term outcomes.

  14. Pathophysiology of Cisplatin-Induced Acute Kidney Injury

    Directory of Open Access Journals (Sweden)

    Abdullah Ozkok

    2014-01-01

    Full Text Available Cisplatin and other platinum derivatives are the most widely used chemotherapeutic agents to treat solid tumors including ovarian, head and neck, and testicular germ cell tumors. A known complication of cisplatin administration is acute kidney injury (AKI. The nephrotoxic effect of cisplatin is cumulative and dose-dependent and often necessitates dose reduction or withdrawal. Recurrent episodes of AKI may result in chronic kidney disease. The pathophysiology of cisplatin-induced AKI involves proximal tubular injury, oxidative stress, inflammation, and vascular injury in the kidney. There is predominantly acute tubular necrosis and also apoptosis in the proximal tubules. There is activation of multiple proinflammatory cytokines and infiltration of inflammatory cells in the kidney. Inhibition of the proinflammatory cytokines TNF-α or IL-33 or depletion of CD4+ T cells or mast cells protects against cisplatin-induced AKI. Cisplatin also causes endothelial cell injury. An understanding of the pathogenesis of cisplatin-induced AKI is important for the development of adjunctive therapies to prevent AKI, to lessen the need for dose decrease or drug withdrawal, and to lessen patient morbidity and mortality.

  15. GAGs and GAGs diseases: when pathophysiology supports the clinic.

    Science.gov (United States)

    Costantini, Elisabetta; Lazzeri, Massimo; Porena, Massimo

    2013-01-01

    The urinary epithelium has been the subject of considerable interest and much research in recent years. What has radically changed in the last decade is the concept of what the bladder epithelium really is. It is currently no longer considered just a simple barrier and a non-specific defence against infections, and it has been recognized as a specialized tissue regulating complex bladder functions and playing a fundamental and active role in the pathogenesis of cystitis. Researchers have been focussing on the receptors and mediators that are active in the sub-epithelial layer, with the hope that understanding the role of the urothelium defect will offer the opportunity for new therapeutic strategies. On the surface of the urothelial umbrella-cells there is a thick layer of glycoproteins and proteoglycans, which together are called Glycosaminoglycans (GAGs). They constitute a hydrophilic mucosal coating and act as a barrier against solutes found in urine. In recent years they have received special attention because injury to Gags, due to different noxae, has been identified as the first step in the genesis of chronic inflammatory bladder diseases, such as recurrent urinary tract infections, chemical or radiation cystitis, interstitial cystitis and/or Bladder Pain Syndrome. Aim of this study is to define the importance of the urothelium starting from the anatomy and physiology of the bladder wall. Furthermore, we will underline the role of glycosaminoglycans, focusing both on their pathophysiological role in the principal bladder diseases and on the therapeutic aspects from the clinical point of view.

  16. Translation of clinical problems in osteoarthritis into pathophysiological research goals.

    Science.gov (United States)

    van der Kraan, Peter M; Berenbaum, Francis; Blanco, Francisco J; Cosimo, de Bari; Lafeber, Floris; Hauge, Ellen; Higginbottom, Adele; Ioan-Facsinay, Andreea; Loughlin, John; Meulenbelt, Ingrid; Moilanen, Eeva; Pitsillidou, Irene; Tsezou, Aspasia; van Meurs, Joyce; Vincent, Tonia; Wittoek, Ruth; Lories, Rik

    2016-01-01

    Osteoarthritis (OA) accounts for more disability among the elderly than any other disease and is associated with an increased mortality rate. The prevalence in Europe will rise in the future since this continent has a strongly ageing population and an obesity epidemic; obesity and age both being major risk factors for OA. No adequate therapeutic options, besides joint replacement, are available, although they are greatly needed and should be acquired by adequate research investments. However, the perspective on OA from a researcher's point of view is not always aligned with the perspective of a patient with OA. Researchers base their views on OA mainly on abnormalities in structure and function while patients consider OA as a collection of symptoms. In this viewpoint paper, we discuss the possibility of translating the most important clinical problems into pathophysiological research goals to facilitate the translation from bench to bedside and vice versa. This viewpoint is the outcome of a dialogue within the 'European League Against Rheumatism study group on OA' and People with Arthritis/Rheumatism across Europe (PARE) representatives.

  17. The pathophysiology of hypertension in patients with obesity.

    Science.gov (United States)

    DeMarco, Vincent G; Aroor, Annayya R; Sowers, James R

    2014-06-01

    The combination of obesity and hypertension is associated with high morbidity and mortality because it leads to cardiovascular and kidney disease. Potential mechanisms linking obesity to hypertension include dietary factors, metabolic, endothelial and vascular dysfunction, neuroendocrine imbalances, sodium retention, glomerular hyperfiltration, proteinuria, and maladaptive immune and inflammatory responses. Visceral adipose tissue also becomes resistant to insulin and leptin and is the site of altered secretion of molecules and hormones such as adiponectin, leptin, resistin, TNF and IL-6, which exacerbate obesity-associated cardiovascular disease. Accumulating evidence also suggests that the gut microbiome is important for modulating these mechanisms. Uric acid and altered incretin or dipeptidyl peptidase 4 activity further contribute to the development of hypertension in obesity. The pathophysiology of obesity-related hypertension is especially relevant to premenopausal women with obesity and type 2 diabetes mellitus who are at high risk of developing arterial stiffness and endothelial dysfunction. In this Review we discuss the relationship between obesity and hypertension with special emphasis on potential mechanisms and therapeutic targeting that might be used in a clinical setting.

  18. Endogenous nitric oxide synthesis: biological functions and pathophysiology.

    Science.gov (United States)

    Bredt, D S

    1999-12-01

    Modern molecular biology has revealed vast numbers of large and complex proteins and genes that regulate body function. By contrast, discoveries over the past ten years indicate that crucial features of neuronal communication, blood vessel modulation and immune response are mediated by a remarkably simple chemical, nitric oxide (NO). Endogenous NO is generated from arginine by a family of three distinct calmodulin- dependent NO synthase (NOS) enzymes. NOS from endothelial cells (eNOS) and neurons (nNOS) are both constitutively expressed enzymes, whose activities are stimulated by increases in intracellular calcium. Immune functions for NO are mediated by a calcium-independent inducible NOS (iNOS). Expression of iNOS protein requires transcriptional activation, which is mediated by specific combinations of cytokines. All three NOS use NADPH as an electron donor and employ five enzyme cofactors to catalyze a five-electron oxidation of arginine to NO with stoichiometric formation of citrulline. The highest levels of NO throughout the body are found in neurons, where NO functions as a unique messenger molecule. In the autonomic nervous system NO functions NO functions as a major non-adrenergic non-cholinergic (NANC) neurotransmitter. This NANC pathway plays a particularly important role in producing relaxation of smooth muscle in the cerebral circulation and the gastrointestinal, urogenital and respiratory tracts. Dysregulation of NOS activity in autonomic nerves plays a major role in diverse pathophysiological conditions including migraine headache, hypertrophic pyloric stenosis and male impotence. In the brain, NO functions as a neuromodulator and appears to mediate aspects of learning and memory. Although endogenous NO was originally appreciated as a mediator of smooth muscle relaxation, NO also plays a major role in skeletal muscle. Physiologically muscle-derived NO regulates skeletal muscle contractility and exercise-induced glucose uptake. nNOS occurs at the

  19. Pathophysiology and a Rational Basis of Therapy.

    Science.gov (United States)

    Gracia-Sancho, Jordi; Maeso-Díaz, Raquel; Bosch, Jaime

    2015-01-01

    sufficiently to promote the development of intrahepatic shunts and portal-systemic collaterals, including varices, through which portal blood flow bypasses the liver. In human portal hypertension collateralization and hyperdynamic circulation start at a portal pressure gradient >10 mm Hg. Rational therapy for portal hypertension aims at correcting these pathophysiological abnormalities: liver injury, fibrogenesis, increased hepatic vascular tone and splanchnic vasodilatation. Continuing liver injury may be counteracted specifically by etiological treatments (the best example being the direct-acting antivirals for hepatitis C viral infection), while architectural disruption and fibrosis can be ameliorated by a variety of antifibrotic drugs and antiangiogenic strategies. Several drugs in this category are currently under investigation in phase II-III randomized controlled trials. Sinusoidal endothelial dysfunction is ameliorated by statins as well as by other drugs increasing NO availability. It is of note that simvastatin has already been proven to be clinically effective in two randomized controlled trials. Splanchnic hyperemia can be counteracted by nonselective β-blockers (NSBBs), vasopressin analogs and somatostatin analogs, drugs that until recently were the only available treatments for portal hypertension, but that are not very effective in the initial stages of cirrhosis. There is experimental and clinical evidence indicating that a more effective reduction of portal pressure is obtained by combining agents acting on these different pathways. It is likely that the treatment of portal hypertension will evolve to use etiological treatments together with antifibrotic agents and/or drugs improving sinusoidal endothelial function in the initial stages of cirrhosis (preprimary prophylaxis), while NSBBs will be added in advanced stages of the disease.

  20. The Status of Rotational Nonequilibrium in HF Chemical Lasers

    Science.gov (United States)

    1986-05-01

    later study from the same laboratory, Copeland et al. 5 3 used a NdYAG dye laser to pump HF into v = 2, j, and an HF pulsed laser to probe various P 2(J... Weston , Jr., J. Chem. Phys. 77, 4776 (1982). 51. J. J. Hinchen and R. H. Hobbs, Appl. Phys. 50, 628 (1979). 52. j. K. Lambert, G. M. Jursich, and F. F...Crim, Chem. Phys. Lett. 71, 258 (1980). 53. R. A. Copeland , D. J. Pearson, and F. F. Crim, Chem. Phys. Lett. 81, 541 (1981). 54. T. J. Foster and F. F

  1. New active load voltage clamp for HF-link converters

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.; Andersen, M.A.E.

    2005-07-01

    This paper proposes a new active clamp for HF-link converters, which features very high efficiency by returning the clamped energy back to the primary side through a small auxiliary converter. It also increases the reliability of HF-link converters by providing an alternative load current path during malfunctions of the secondary bidirectional bridge. The feasibility of the approach is shown on audio power amplifier prototype. New integrated magnetics design is presented that incorporates both the main power and auxiliary transformer on the same magnetic core. (au)

  2. HF-induced airglow at magnetic zenith: theoretical considerations

    Directory of Open Access Journals (Sweden)

    E. V. Mishin

    2005-01-01

    Full Text Available Observations of airglow at 630nm (red line and 557.7nm (green line during HF modification experiments at the High Frequency Active Auroral Research Program (HAARP heating facility are analyzed. We propose a theoretical framework for understanding the generation of Langmuir and ion acoustic waves during magnetic zenith injections. We show that observations of HF-induced airglow in an underdense ionosphere as well as a decrease in the height of the emitting volume are consistent with this scenario.

  3. HF-hash : Hash Functions Using Restricted HFE Challenge-1

    CERN Document Server

    Dey, Dhananjoy; Gupta, Indranath Sen

    2009-01-01

    Vulnerability of dedicated hash functions to various attacks has made the task of designing hash function much more challenging. This provides us a strong motivation to design a new cryptographic hash function viz. HF-hash. This is a hash function, whose compression function is designed by using first 32 polynomials of HFE Challenge-1 with 64 variables by forcing remaining 16 variables as zero. HF-hash gives 256 bits message digest and is as efficient as SHA-256. It is secure against the differential attack proposed by Chabaud and Joux as well as by Wang et. al. applied to SHA-0 and SHA-1.

  4. Hf--Co--B alloys as permanent magnet materials

    Energy Technology Data Exchange (ETDEWEB)

    McGuire, Michael Alan; Rios, Orlando; Ghimire, Nirmal Jeevi

    2017-01-24

    An alloy composition is composed essentially of Hf.sub.2-XZr.sub.XCo.sub.11B.sub.Y, wherein 0Hf.sub.2-XZr.sub.XCo.sub.11B.sub.Y, wherein 0.ltoreq.X<2 and 0

  5. First HF radar measurements of summer mesopause echoes at SURA

    Directory of Open Access Journals (Sweden)

    A. N. Karashtin

    Full Text Available HF sounding of the mesosphere was first carried out at SURA in summer 1994 at frequencies in the range 8–9 MHz using one of the sub-arrays of the SURA heating facility. The observations had a range resolution of 3 km. Almost all measurements indicated the presence of strong radar returns from altitudes between 83 and 90 km with features very similar to VHF measurements of mesopause summer echoes at mid-latitudes and polar mesopause summer echoes. In contrast to VHF observations, HF mesopause echoes are almost always present.

  6. New active load voltage clamp for HF-link converters

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    This paper proposes a new active clamp for HF-link converters, which features very high efficiency by returning the clamped energy back to the primary side through a small auxiliary converter. It also increases the reliability of HF-link converters by providing an alternative load current path du...... during malfunctions of the secondary bidirectional bridge. The feasibility of the approach is shown on audio power amplifier prototype. New integrated magnetics design is presented that incorporates both the main power and auxiliary transformer on the same magnetic core....

  7. First HF radar measurements of summer mesopause echoes at SURA

    Science.gov (United States)

    Karashtin, A. N.; Shlyugaev, Y. V.; Abramov, V. I.; Belov, I. F.; Berezin, I. V.; Bychkov, V. V.; Eryshev, E. B.; Komrakov, G. P.

    1997-07-01

    HF sounding of the mesosphere was first carried out at SURA in summer 1994 at frequencies in the range 8-9 MHz using one of the sub-arrays of the SURA heating facility. The observations had a range resolution of 3 km. Almost all measurements indicated the presence of strong radar returns from altitudes between 83 and 90 km with features very similar to VHF measurements of mesopause summer echoes at mid-latitudes and polar mesopause summer echoes. In contrast to VHF observations, HF mesopause echoes are almost always present.

  8. European coordination for coastal HF radar data in EMODnet Physics

    Science.gov (United States)

    Mader, Julien; Novellino, Antonio; Gorringe, Patrick; Griffa, Annalisa; Schulz-Stellenfleth, Johannes; Montero, Pedro; Montovani, Carlo; Ayensa, Garbi; Vila, Begoña; Rubio, Anna; Sagarminaga, Yolanda

    2015-04-01

    Historically, joint effort has been put on observing open ocean, organizing, homogenizing, sharing and reinforcing the impact of the acquired information based on one technology: ARGO with profilers Argo floats, EuroSites, ESONET-NoE, FixO3 for deep water platforms, Ferrybox for stations in ships of opportunities, and GROOM for the more recent gliders. This kind of networking creates synergies and makes easier the implementation of this source of data in the European Data exchange services like EMODnet, ROOSs portals, or any applied services in the Blue economy. One main targeted improvement in the second phase of EMODnet projects is the assembling of data along coastline. In that sense, further coordination is recommended between platform operators around a specific technology in order to make easier the implementation of the data in the platforms (4th EuroGOOS DATAMEQ WG). HF radar is today recognized internationally as a cost-effective solution to provide high spatial and temporal resolution current maps (depending on the instrument operation frequency, covering from a few kilometres offshore up to 200 km) that are needed for many applications for issues related to ocean surface drift or sea state characterization. Significant heterogeneity still exists in Europe concerning technological configurations, data processing, quality standards and data availability. This makes more difficult the development of a significant network for achieving the needed accessibility to HF Radar data for a pan European use. EuroGOOS took the initiative to lead and coordinate activities within the various observation platforms by establishing a number of Ocean Observing Task Teams such as HF-Radars. The purpose is to coordinate and join the technological, scientific and operational HF radar communities at European level. The goal of the group is on the harmonization of systems requirements, systems design, data quality, improvement and proof of the readiness and standardization of

  9. Potential Use of HF Radar for Tsunami Detection in the Central and Eastern Mediterranean

    Science.gov (United States)

    Cokacar, Tulay; Necmioglu, Ocal; Ozer, Ceren

    2016-04-01

    Today, HF radar is recognized as internationally cost-effective and efficient solution to provide near-real time measurements that cover a large area continuously over time for ocean hazards warning and long term ocean monitoring studies such as, seasonal forecasts of climate, hurricanes, s torm surges and large-scale ocean circulation changes. These radar systems recently became an operational tool in coastal monitoring worldwide. They are used for many operational applications that include ship detection, tracking, guidance, distribution of pollutants, fishery and oceanography. HF radar data used for the tsunami warnings, can also be used for the other purposes and be of potential interest to wide application area users and stakeholders. Moreover multi user applications will ensure the system is maintained operationally over the long term. Hence the system is cost effective also with regards to maintenance. New algorithms allow useful detection and verification for tsunami detection. While technical monitoring capacity and the algorithms for tsunami detection is improved significantly, further studies are required to obtain complete wave height determination. We analysed the available technology and algorithms for the purpose of tsunami detection in the central-eastern Mediterranean and its connected Seas (Aegean and Black Sea). Since the study area is characterized by narrow continental shelf area, the HF radar observation for the purpose of tsunami detection is possible in restricted areas. While extensive continental shelves in the northeastern Black Sea and along the coast of Tunisia in the central Mediterranean let tsunami detection 2.5 hours before tsunami waves hit the coast, the detection is possible around 1 hr or less in advance for the remaining basins with wide continental shelf areas. The bathymetric structure is important for deciding the applicability of HF radar systems for the tsunami detection in continental shelf areas, which can be covered by

  10. Oxygen engineering of HfO{sub 2-x} thin films grown by reactive molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrandt, Erwin; Kurian, Jose; Alff, Lambert [Institut fuer Materialwissenschaft, TU-Darmstadt (Germany); Zaumseil, Peter; Schroeder, Thomas [IHP, Frankfurt, Oder (Germany)

    2010-07-01

    Reactive molecular beam epitaxy (R-MBE) is an ideal tool for tailoring physical properties of thin films to specific needs. For the development of cutting-edge oxides for thin film applications a precise control of oxygen defects is crucial. R-MBE in combination with rf-activated oxygen allows reproducibly growing oxide thin films with precise oxidation conditions enabling oxygen engineering. R-MBE was used to grow Hf and HfO{sub 2{+-}}{sub x} thin films with different oxidation conditions on sapphire single crystal substrates. Structural characterization was carried out using rotating anode x-ray diffraction revealing highly textured to epitaxial thin films on c-cut sapphire. Furthermore, switching of film orientation by varying the oxidation conditions was observed demonstrating the role of oxygen in the growth procedure. The investigation of electrical properties using a four probe measurement setup showed conductivities in the range of 1000 {mu}{omega}cm for oxygen deficient HfO{sub 2-x} thin films. Optical properties were investigated using a photospectrometer and additionally x-ray photoelectron spectroscopy was carried out to study the band gap and valence states. Both techniques were used to monitor the oxygen content in deficient HfO{sub 2-x} thin films. Our results demonstrate the importance of oxygen engineering even in the case of 'simple' oxides.

  11. Evolution of E2 transition strength in deformed hafnium isotopes from new measurements on $^{172}$Hf, $^{174}$Hf, and $^{176}$Hf

    CERN Document Server

    Rudigier, M; Dannhoff, M; Gerst, R-B; Jolie, J; Saed-Samii, N; Stegemann, S; Régis, J-M; Robledo, L M; Rodríguez-Guzmán, R; Blazhev, A; Fransen, Ch; Warr, N; Zell, K O

    2015-01-01

    The available data for E2 transition strengths in the region between neutron-deficient Hf and Pt isotopes are far from complete. More and precise data are needed to enhance the picture of structure evolution in this region and to test state-of-the-art nuclear models. In a simple model, the maximum collectivity is expected at the middle of the major shell. However, for actual nuclei, this picture may no longer be the case, and one should use a more realistic nuclear-structure model. We address this point by studying the spectroscopy of Hf. We remeasure the 2^+_1 half-lives of 172,174,176Hf, for which there is some disagreement in the literature. The main goal is to measure, for the first time, the half-lives of higher-lying states of the rotational band. The new results are compared to a theoretical calculation for absolute transition strengths. The half-lives were measured using \\gamma-\\gamma and conversion-electron-\\gamma delayed coincidences with the fast timing method. For the determination of half-lives i...

  12. Electron dominated thermoelectric response in MNiSn (M: Ti, Zr, Hf) half-Heusler alloys

    KAUST Repository

    Gandi, Appala

    2016-05-09

    We solve the transport equations of the electrons and phonons to understand the thermoelectric behaviour of the technologically important half-Heusler alloys MNiSn (M: Ti, Zr, Hf). Doping is simulated within the rigid band approximation. We clarify the origin of the electron dominated thermoelectric response and determine the carrier concentrations with maximal figures of merit. The phonon mean free path is studied to calculate the grain size below which grain refinement methods can enforce ballistic heat conduction to enhance the figure of merit. © The Owner Societies 2016.

  13. Comparative study of atomic-layer-deposited HfO2/Al2O3, Hf0.8Al0.2Ox and Hf0.5Al0.5Ox on N-GaAs

    Science.gov (United States)

    Yu, Xinjiang; Lv, Hongliang; Zhang, Yuming; Zhang, Yimen; Qin, Zaiyang

    2016-11-01

    Interfacial properties of n-GaAs metal-oxide-semiconductor (MOSCAPs) with the gate dielectrics of HfO2/Al2O3, Hf0.8Al0.2Ox and Hf0.5Al0.5Ox are investigated. The results reveal that Hf0.5Al0.5Ox has larger permittivity and lower interface trap density than that of HfO2/Al2O3. In order to explain the result from the physical perspective, the XPS tests of all three samples are performed. It is found that the main reason to form interface trap of three samples treated with 500 °C post-deposition annealing, is attributed to the interfacial component of Ga2O3 and The Hf0.5Al0.5Ox dielectric is beneficial to reducing the formation of Ga2O3.

  14. Interstitial Cells of Cajal: A Novel Hypothesis for the Pathophysiology of Irritable Bowel Syndrome

    Directory of Open Access Journals (Sweden)

    Ahad Eshraghian

    2011-01-01

    Full Text Available Irritable bowl syndrome (IBS affects a large proportion of the world’s population, and accounts for a considerable number of visits to gastroenterologists and general practitioners. Despite its high prevalence, the precise mechanism of IBS has not been identified to date. The interstitial cells of Cajal (ICC participate in the production of slow waves and the regulation of their propagation through the gastrointestinal system; thus, they are important components of gastrointestinal motility. The present review proposes that ICC play a central role in the pathophysiology of IBS. This hypothesis is based on many links between ICC and currently proposed mechanisms of IBS pathophysiology. It appears that ICC may be involved in almost all of the previously explained pathogenic mechanisms of IBS. If proven, this hypothesis may provide a key to solving the IBS mystery.

  15. Finishing and Commissioning the New Arecibo HF Facility

    Science.gov (United States)

    Sulzer, M. P.; Gonzalez, S. A.

    2011-12-01

    , one is excited 120 degrees ahead, and the other 120 degrees behind. The two elements in each crossed pair must have currents shifted by 90 degrees. In most systems all the elements excited 90 degrees apart are also spatially orthogonal. That is not the case in this array; modeling results showed better array performance with this geometry. Recent analysis shows that it might be necessary to excite the transmitters at 90 degrees plus or minus some offset in order to achieve 90 degrees in the antenna currents. We must make the measurements to determine the size of this offset. The electrical substation that provides power to the transmitters and the heat exchangers providing cooling is complete. Wiring of the power to the transmitters is nearly complete; we are beginning the commissioning of the transmitters. Four one MW generators have been installed; we have tested the power system with the 430 MHz transmitter and the site together. This system provides a flexible complete way to power the planetary radar, the HF facility, and site backup,as well as the 430 transmitter if required. The commissioning tasks that we complete in the next few months will affect the scientific usefulness of the facility, especially in the first campaign. It is important that we bring up the system in an efficient and orderly fashion.

  16. [Pathophysiology of vascular complications in diabetes].

    Science.gov (United States)

    Yasunari, K; Kohno, M; Yoshikawa, J

    1999-07-01

    Hyperglycemia is an important causative factor in the development of micro- and macrovascular complications in diabetes. It activates polyol pathway and protein kinase C, which result in the increase in insulin resistance and oxidative stress in vascular tissues, leading to the accelerated atherosclerosis. Increased hematocrit and blood viscosity are observed in diabetes, which contribute to an increased risk of thrombosis and accelerated vasculopathy. Blood glucose control as well as blood pressure control are important in the prevention of diabetic vascular complications as evidenced by large-scale interventional studies.

  17. First 100 ms of HF modification at Tromso, Norway

    Science.gov (United States)

    Djuth, F. T.; Isham, B.; Rietveld, M. T.; Hagfors, T.; La Hoz, C.

    Experiments were performed with the high-power high-frequency HF facility at Troms o Norway to test theoretical predictions for the excitation of ion and Langmuir oscillations in the ionosphere The principal diagnostic of wave-plasma interactions was the VHF radar at the European Incoherent Scatter EISCAT facility High resolution radar techniques were used to monitor the temporal development of the ion and Langmuir oscillations HF pulses 100 ms in duration were periodically transmitted into a smooth background F region plasma Measurements of the radar backscatter spectra show that all key spectral features predicted by strong Langmuir turbulence SLT theory modified Zakharov model are simultaneously present in the plasma and that their evolution is in agreement with theoretical expectations However several new features have been observed that cannot be anticipated by current theory because of limitations in the electric field strength within the simulations The experimental results reinforce the notion that new theoretical developments are needed to accommodate the large HF electric fields produced at Troms o and HAARP Gakona Alaska and to treat the electron acceleration process in a self-consistent fashion The F region response to two HF effective radiated power levels sim 58 MW and sim 125 MW was investigated at Troms o These ERP values include absorptive losses resulting from the sunlit D region In general the results at 58 MW ERP and 125 MW ERP are consistent with many of the SLT

  18. The multilayer Fe/Hf studied with slow positron beam

    Science.gov (United States)

    Murashige, Y.; Tashiro, M.; Nakajyo, T.; Koizumi, T.; Kanazawa, I.; Komori, F.; Ito, Y.

    1997-04-01

    The positron annihilation parameter versus the incident positron energy is measured in the thin Fe films and the Fe/Hf bilayer on silica substrate, by means of the variable energetic slow-positron beam technique. We have analyzed the change in open-volume spaces and vacancy-type defects among the Fe microcrystals in these thin films with the deposition temperature.

  19. A CMOS OTA for HF filters with programmable transfer function

    NARCIS (Netherlands)

    van de Zwan, Eric J.; Klumperink, Eric A.M.; Seevinck, E.; Seevinck, Evert

    1991-01-01

    A CMOS operational transconductance amplifier (OTA) for programmable HF filters is presented. When used in an OTA-C integrator, the unity-gain frequency phase error remains less than 0.3° for frequencies up to more than one tenth of the OTA bandwidth. The OTA has built-in phase compensation, which

  20. Hf isotope evidence for a hidden mantle reservoir

    DEFF Research Database (Denmark)

    Bizzarro, Martin; Simonetti, A.; Stevenson, R.K.

    2002-01-01

    High-precision Hf isotopic analyses and U-Pb ages of carbonatites and kimberlites from Greenland and eastern North America, including Earth's oldest known carbonatite (3 Ga), indicate derivation from an enriched mantle source. This previously unidentified mantle reservoir-marked by an unradiogeni...

  1. Origin of excess 176Hf in meteorites

    DEFF Research Database (Denmark)

    Thrane, Kristine; Connelly, James; Bizzarro, Martin

    2010-01-01

    After considerable controversy regarding the (176)Lu decay constant (lambda(176)Lu), there is now widespread agreement that (1.867 +/- 0.008) x 10(-11) yr(-1) as confirmed by various terrestrial objects and a 4557 Myr meteorite is correct. This leaves the (176)Hf excesses that are correlated with...

  2. Corticosteroid-Induced Osteoporosis in Daily Practice: Pathophysiology, Clinical Importance, Prevention and Intervention Strategies

    NARCIS (Netherlands)

    A. Struijs (Ard)

    2000-01-01

    textabstractGlucocorticoid-induced osteoporosis is a serious disease that strikes millions of people world-wide every year. Nevertheless much debate is still going on about the preferred strategies to be followed and the magnitude of the problem. Therefore, the first aim of this thesis was to review

  3. Endothelial dysfunction. An important mediator in the pathophysiology of hypertension during pre-eclampsia.

    Science.gov (United States)

    Lamarca, B

    2012-08-01

    Pre-eclampsia is defined as new onset hypertension with proteinuria during pregnancy. It affects approximately 5% of pregnancies in the US with a subset of those progressing into more severe forms of the disease, known as HELLP or eclampsia. Pre-eclampsia is associated with intrauterine growth restriction, chronic immune activation and multi-organ endothelial dysfunction thus contributing to the clinically visible elevation in maternal blood pressure. The end result is increased infant and maternal morbidity and mortality thereby contributing to the gross health care expenditure nationwide. Although the underlying cause of this disease is still unknown, the most well accepted hypothesis is that placental ischemia/hypoxia results from inadequate uteroplacental vascular remodeling, which leads to a decrease in placental blood flow. The ischemic placenta releases factors such as the soluble VEGF receptor-1 (sFlt-1), the angiotensin II type-1 receptor autoantibody (AT1-AA), and cytokines such as TNF-α and Interleukin 6 which cause maternal endothelial dysfunction characterized by elevated circulating endothelin (ET-1), reactive oxygen species (ROS), and enhanced vascular sensitivity to angiotensinII. These factors act in concert to decrease renal function and cause hypertension during pregnancy. Understanding the link between placental ischemia, endothelial dysfunction and hypertension during pregnancy will lend to better prediction, prevention and treatment strategies for women and children stricken by this devastating disease.

  4. Self-diffusion of Er and Hf inpure and HfO/sub 2/-doped polycrystalline Er/sub 2/O/sub 3/. [Hf-175 and Er-169

    Energy Technology Data Exchange (ETDEWEB)

    Scheidecker, R.W.

    1979-01-01

    Using a tracer technique, self-diffusion of Er and Hf was measured over the approximate temperature interval of 1600 to 1970/sup 0/C in pure and HfO/sub 2/-doped polycryatalline Er/sub 2/O/sub 3/. Up to about 10 m/o HfO/sub 2/ dopant level, the Er self-diffusion coefficients followed a relationship based on cation vacancies. Above 10 m/o HfO/sub 2/, deviation from this relationship occurred, apparently due to clustering of cation vacancies and oxygen interstitials around the dopant hafnia ion. The activation energy for the self-diffusion of Er in pure Er/sub 2/O/sub 3/ was 82.2 Kcal/mole and increased with the HfO/sub 2/ dopant level present. Self-diffusion of Hf was measured in pure Er/sub 2/O/sub 3/ having two impurity levels, and a separation of the grain boundary. The volume diffusion of Hf showed both extrinsic and intrinsic behavior with the transition temperature increasing with the impurity level present in Er/sub 2/O/sub 3/. The activation energy for Hf volume diffusion in the intrinsic region was high, i.e. 235 -+ 9.5 Kcal/mole. The grain boundary diffusion was apparently extrinsic over the entire temperature interval Very low Hf self diffusion rates were found in both pure and HfO/sub 2/ doped Er/sub 2/O/sub 3/ compositions. Despite a clustering effect, the HfO/sub 2/ dopant increased the Hf volume diffusion coefficients.

  5. The pathophysiology of the migraine attack

    NARCIS (Netherlands)

    E.L.H. Spierings

    1980-01-01

    textabstractMigraine, a word of French origin, is a mediaeval corruption of the Greek hemicrania". Its etymological meaning, half-headache, indicates two important features of the disorder, the headache and its onesidedness. In classical migraine, the headache is preceded by an 'aura' of focal neuro

  6. Helium implanted $\\rm\\underline{Al}$Hf as studied by 181Ta TDPAC

    Indian Academy of Sciences (India)

    R Govindaraj; K P Gopinathan; B Viswanathan

    2000-06-01

    Time differential perturbed angular correlation (TDPAC) measurement on $\\rm\\underline{Al}$Hf reference sample has shown that a fraction 0.88 of probe nuclei are defect free and are occupying the substitutional sites in fcc Al matrix, and the remaining are associated with Hf solute clusters. Measurements on helium implanted sample indicate the binding of helium associated defects by Hf solute clusters. Isochronal annealing measurements indicate the dissociation of the helium implantation induced defects from Hf solute clusters for annealing treatments beyond 650 K. On comparison of the present results with that reported in $\\rm\\underline{Cu}$Hf subjected to identical helium implantation, it is inferred that the Hf solute clusters in $\\rm\\underline{Al}$Hf bind less strongly the helium associated defects than in $\\rm\\underline{Cu}$Hf.

  7. Processing and crystallographic structure of non-equilibrium Si-doped HfO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Dong; Fancher, Chris M.; Esteves, Giovanni; Jones, Jacob L., E-mail: jacobjones@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Zhao, Lili [School of Information Science and Technology, Northwest University, Xi' an 710127 (China)

    2015-06-28

    Si-doped HfO{sub 2} was confirmed to exist as a non-equilibrium state. The crystallographic structures of Si-doped HfO{sub 2} were studied using high-resolution synchrotron X-ray diffraction and the Rietveld refinement method. Incorporation of Si into HfO{sub 2} and diffusion of Si out of (Hf,Si)O{sub 2} were determined as a function of calcination temperature. Higher thermal energy input at elevated calcination temperatures resulted in the formation of HfSiO{sub 4}, which is the expected major secondary phase in Si-doped HfO{sub 2}. The effect of SiO{sub 2} particle size (nano- and micron-sized) on the formation of Si-doped HfO{sub 2} was also determined. Nano-crystalline SiO{sub 2} was found to incorporate into HfO{sub 2} more readily.

  8. Data of evolutionary structure change: 1CLMA-2HF5A [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1CLMA-2HF5A 1CLM 2HF5 A A LTEEQIAEFKEAFALFDKDGDGTITTKELGTVMRSLGQN...PTEAELQDMINEVDADGNGTIDFPEFLSLMARKMKEQDSEEELIEAFKVFDRDGNGLISAAELRHVMTNLGEKL--TDDEVDEMIREADIDGDGHINYEEFVRMMVS-...ntryChain> 1CLM A 1CLMA LGEKL--TD...ne> 1CLM A 1CLMA

  9. The importance of elevation angle measurements in HF radar investigations of the ionosphere

    Science.gov (United States)

    Greenwald, Raymond A.; Frissell, Nathaniel; de Larquier, Sebastien

    2017-03-01

    We evaluate the performance of three methods for determining the ground range and refractive index of ionospheric scattering volumes. Each method uses the same equivalent path analysis with the latter parameter derived through the additional use of Snell's law. Two of these methods make their predictions using the group range and a virtual height model for each scattering volume; the third method uses the group range and the elevation angle of the ray. The effectiveness of each of these methods is evaluated using ray tracing through a simulated reference ionosphere. Ray tracings provide determinations of the initial elevation angle and group range of the transmitted signal and the ground range and refractive index of the scattering volume. The first pair of parameters is used as inputs to the geolocation methods, and the second pair becomes part of a data set against which the predictions of the geolocation methods are evaluated. We find that the geolocation methods using virtual height models change the initial elevation angle to a value that is consistent with their virtual height model but inconsistent with ray tracing. Consequently, predictions of ground range and refractive index from methods using virtual height models are rarely consistent with predictions from ray tracing. In contrast, the third method uses the initial elevation angle from ray tracing and yields accurate predictions in the bottomside ionosphere. Two modifications were made to this method to extend the agreement between it and ray tracing to all backscattered signals.

  10. Requirements for the formal representation of pathophysiology mechanisms by clinicians.

    Science.gov (United States)

    de Bono, B; Helvensteijn, M; Kokash, N; Martorelli, I; Sarwar, D; Islam, S; Grenon, P; Hunter, P

    2016-04-01

    Knowledge of multiscale mechanisms in pathophysiology is the bedrock of clinical practice. If quantitative methods, predicting patient-specific behaviour of these pathophysiology mechanisms, are to be brought to bear on clinical decision-making, the Human Physiome community and Clinical community must share a common computational blueprint for pathophysiology mechanisms. A number of obstacles stand in the way of this sharing-not least the technical and operational challenges that must be overcome to ensure that (i) the explicit biological meanings of the Physiome's quantitative methods to represent mechanisms are open to articulation, verification and study by clinicians, and that (ii) clinicians are given the tools and training to explicitly express disease manifestations in direct contribution to modelling. To this end, the Physiome and Clinical communities must co-develop a common computational toolkit, based on this blueprint, to bridge the representation of knowledge of pathophysiology mechanisms (a) that is implicitly depicted in electronic health records and the literature, with (b) that found in mathematical models explicitly describing mechanisms. In particular, this paper makes use of a step-wise description of a specific disease mechanism as a means to elicit the requirements of representing pathophysiological meaning explicitly. The computational blueprint developed from these requirements addresses the Clinical community goals to (i) organize and manage healthcare resources in terms of relevant disease-related knowledge of mechanisms and (ii) train the next generation of physicians in the application of quantitative methods relevant to their research and practice.

  11. Geographic variations in the PARADIGM-HF heart failure trial.

    Science.gov (United States)

    Kristensen, Søren Lund; Martinez, Felipe; Jhund, Pardeep S; Arango, Juan Luis; Bĕlohlávek, Jan; Boytsov, Sergey; Cabrera, Walter; Gomez, Efrain; Hagège, Albert A; Huang, Jun; Kiatchoosakun, Songsak; Kim, Kee-Sik; Mendoza, Iván; Senni, Michele; Squire, Iain B; Vinereanu, Dragos; Wong, Raymond Ching-Chiew; Gong, Jianjian; Lefkowitz, Martin P; Rizkala, Adel R; Rouleau, Jean L; Shi, Victor C; Solomon, Scott D; Swedberg, Karl; Zile, Michael R; Packer, Milton; McMurray, John J V

    2016-11-01

    The globalization of clinical trials has highlighted geographic variations in patient characteristics, event rates, and treatment effects. We investigated these further in PARADIGM-HF, the largest and most globally representative trial in heart failure (HF) to date. We looked at five regions: North America (NA) 602 (8%), Western Europe (WE) 1680 (20%), Central/Eastern Europe/Russia (CEER) 2762 (33%), Latin America (LA) 1433 (17%), and Asia-Pacific (AP) 1487 (18%). Notable differences included: WE patients (mean age 68 years) and NA (65 years) were older than AP (58 years) and LA (63 years) and had more coronary disease; NA and CEER patients had the worst signs, symptoms, and functional status. North American patients were the most likely to have a defibrillating-device (54 vs. 2% AP) and least likely prescribed a mineralocorticoid receptor antagonist (36 vs. 65% LA). Other evidence-based therapies were used most frequently in NA and WE. Rates of the primary composite outcome of cardiovascular (CV) death or HF hospitalization (per 100 patient-years) varied among regions: NA 13.6 (95% CI 11.7-15.7) WE 9.6 (8.6-10.6), CEER 12.3 (11.4-13.2), LA 11.2 (10.0-12.5), and AP 12.5 (11.3-13.8). After adjustment for prognostic variables, relative to NA, the risk of CV death was higher in LA and AP and the risk of HF hospitalization lower in WE. The benefit of sacubitril/valsartan was consistent across regions. There were many regional differences in PARADIGM-HF, including in age, symptoms, comorbidity, background therapy, and event-rates, although these did not modify the benefit of sacubitril/valsartan. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT01035255. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Cardiology.

  12. Mid-Latitude Mobile Wideband HF- NVIS Channel Analysis: Part 1

    Science.gov (United States)

    2017-09-14

    communications (SATCOM) for beyond line-of- sight (LOS) links. However, standard HF systems operating over a 3-kHz bandwidth do not provide sufficient...wideband mid-latitude HF channel soundings and three-dimensional (3-D) ray-tracing simulations to develop a statistical model of a particular nearly...46 5 THE HF-NVIS CHANNEL SOUNDING SYSTEM ...................................................................... 47 5.1 TRANSMIT AND RECEIVE HF

  13. W/Z$+$jets and W/Z$+$HF$-$jets production at ATLAS

    CERN Document Server

    Vittori, Camilla; The ATLAS collaboration

    2017-01-01

    The production of jets in association with a W or a Z boson in proton-proton collisions is an important process to study QCD in multi-scale environments. Moreover, measurements of W/Z boson production associated with heavy-flavour (HF) quarks provide important experimental constraints to improve the theoretical description of these processes, as the uncertainties in the current predictions are larger than the ones obtained in the inclusive case. The detailed knowledge of the production of jets associated with electroweak gauge bosons is also a key element for the understanding of Higgs initiated processes and Beyond Standard Model searches, as they represent an important background in these measurements. Results for the differential production cross sections for W/Z+jets and W/Z+HF-jets with respect to several kinematics variables measured by the ATLAS in proton-proton collisions at centre-of-mass energies of 7 and 13 TeV are presented and compared to high- order QCD calculations and recent Monte Carlo simula...

  14. W/Z+jets and W/Z+HF-jets production at ATLAS

    CERN Document Server

    Vittori, Camilla; The ATLAS collaboration

    2017-01-01

    The production of jets in association with a W or a Z boson in proton-proton collisions is an important process to study QCD in multi-scale environments. Moreover, measurements of W/Z boson production associated with heavy- flavor (HF) quarks provide important experimental constraints to improve the theoretical description of these processes, as the uncertainties in the current predictions are larger than the ones obtained in the inclusive case. The detailed knowledge of the production of jets associated with electroweak gauge bosons is also a key element for the understanding of Higgs initiated processes and Beyond Standard Model searches, as they represent an important background in these measurements. Results for the differential production cross sections for W/Z+jets and W/Z+HF-jets in several kinematics variables measured by the ATLAS in proton-proton collisions at cms energies of 7 and 13 TeV are presented and compared to high- order QCD calculations and recent Monte Carlo simulations.

  15. KCNK5 in Physiology and Pathophysiology

    DEFF Research Database (Denmark)

    Kirkegaard, Signe Skyum

    to study the effect on physiology and channel expression patterns (Paper II). We found that 48 h of hypotonic stimulation reduced the maximum current through the channel and likewise decreased the cells ability to perform RVD. This impairment was found to be likely due to lowered KCNK5 protein expression...... proposed to play a role in T cell activation and in multiple sclerosis. When a cell experiences swelling do to osmotic changes in the extracellular or intracellular environment most mammalian cells will regulate their volume back towards the starting point – an important feature in keeping cellular...... to be an important player in RVD in different cell types and tissue e.g. in Ehrlich cells. It has been speculated that tyrosine phosphorylation is necessary for the swelling-activation of the channel and in “Paper I” we show how acute hypotonic swelling induces a time-dependent tyrosine phosphorylation upon...

  16. Bioactive lipids in kidney physiology and pathophysiology

    Directory of Open Access Journals (Sweden)

    Daria Sałata

    2014-01-01

    Full Text Available Lipids not only have structural functions, but also play an important role as signaling and regulatory molecules and participate in many cellular processes such as proliferation, differentiation, migration, and apoptosis. Bioactive lipids act both as extracellular mediators, which are associated with receptors on the surface of cells, and intracellular mediators triggering different signal pathways. They are present and active in physiological conditions, and are also involved in the pathogenesis of inflammation, asthma, cancer, diabetes, and hypertension. Bioactive lipids such as derivatives of arachidonic acid and sphingolipids have an important role in renal development, physiology and in many renal diseases. Some of them are potential indicators of kidney damage degree and/or function of the transplanted kidneys.

  17. [Pathophysiology of hypertension in chronic kidney disease].

    Science.gov (United States)

    Sawicka, Magdalena; Jędras, Mirosław

    2014-01-01

    Hypertension is both an important cause and consequence of chronic kidney disease (CKD). It is present in 80-85% of the patients. The article summarizes the main pathogenetic factors of hypertension in CKD such as: sodium retention, increased activity the renin-angiotensin-aldosterone system and sympathetic nervous system, impaired nitric oxide synthesis and endothelium-mediated vasodilatation, oxidative stress, disorders of calcium metabolism and parathyroid hormone secretion, vascular calcification and increased arterial stiffness.

  18. Advanced glycation end-products, a pathophysiological pathway in the cardiorenal syndrome

    NARCIS (Netherlands)

    Willemsen, Suzan; Hartog, Jasper W. L.; Heiner-Fokkema, Rebecca; van Veldhuisen, Dirk J.; Voors, Adriaan A.

    2012-01-01

    The prevalence of heart failure (HF) is increasing. A distinction is made between diastolic HF (preserved left ventricular ejection fraction (LVEF)) and systolic HF (reduced LVEF). Advanced glycation end-products (AGEs) are crystallized proteins that accumulate during ageing, but are particularly in

  19. HF Radar observations of the Dardanelles outflow current in North Eastern Aegean using validated WERA HF radar data

    Directory of Open Access Journals (Sweden)

    Z. KOKKINI

    2015-01-01

    Full Text Available A two-site WERA HF radar station was installed in November 2009 at the eastern coast of Lemnos Island in North Aegean Sea, aiming to monitor the surface inflow of Black Sea waters exiting from the Dardanelles Strait, as well as to constitute a coastal management tool for incidents of oil-pollution or save-and-rescue operations. Strong interference by foreign transmissions is a source of noise deteriorating the quality of the backscattered signal, thus significantly reducing the HF radar’s effective data return rate. In order to ameliorate this problem, further quality-control and data gap interpolating procedures have been developed and applied, to be used in addition to the procedures incorporated and used by the manufacturer’s signal processing software. The second-level processing involves traditional despiking in the temporal domain, preceding Empirical Orthogonal Function analysis. The latter is used not only to filter high-frequency noise but also to fill data gaps in time and space. The data reconstruction procedure has been assessed via comparison of (a HF radial with CODE-type drifter radial velocities as well as (b HF-derived virtual drifter tracks with actual drifter tracks. The main circulation features and their variability, as revealed by the reconstructed fields, are presented.

  20. HF Radar observations of the Dardanelles outflow current in North Eastern Aegean using validated WERA HF radar data

    Directory of Open Access Journals (Sweden)

    Z. KOKKINI

    2014-12-01

    Full Text Available A two-site WERA HF radar station was installed in November 2009 at the eastern coast of Lemnos Island in North Aegean Sea, aiming to monitor the surface inflow of Black Sea waters exiting from the Dardanelles Strait, as well as to constitute a coastal management tool for incidents of oil-pollution or save-and-rescue operations. Strong interference by foreign transmissions is a source of noise deteriorating the quality of the backscattered signal, thus significantly reducing the HF radar’s effective data return rate. In order to ameliorate this problem, further quality-control and data gap interpolating procedures have been developed and applied, to be used in addition to the procedures incorporated and used by the manufacturer’s signal processing software. The second-level processing involves traditional despiking in the temporal domain, preceding Empirical Orthogonal Function analysis. The latter is used not only to filter high-frequency noise but also to fill data gaps in time and space. The data reconstruction procedure has been assessed via comparison of (a HF radial with CODE-type drifter radial velocities as well as (b HF-derived virtual drifter tracks with actual drifter tracks. The main circulation features and their variability, as revealed by the reconstructed fields, are presented.

  1. Incidence, diagnosis and pathophysiology of amniotic fluid embolism.

    Science.gov (United States)

    Ito, F; Akasaka, J; Koike, N; Uekuri, C; Shigemitsu, A; Kobayashi, H

    2014-10-01

    Amniotic fluid embolism (AFE) is a rare clinical entity, sometimes fatal. A review was conducted to describe the frequency, diagnosis and pathophysiology of AFE. The reported incidences ranged from 1.9 cases per 100,000 maternities (UK) to 6.1 per 100,000 maternities (Australia), which can vary considerably, depending on the period, region of study and the definition. Although the development of amniotic fluid-specific markers would have an impact on early diagnosis, definition of AFE based on these markers is not widely accepted. To date, immunological mechanisms, amniotic fluid-dependent anaphylactic reaction and complement activation, have been proposed as potential pathogenetic and pathophysiological mechanisms. Immune cell activation induced through complement activation may be associated with the mechanism that immediately initiates maternal death, only in susceptible individuals. This review will focus on advances in the field of AFE biology and discuss the prevalence, diagnosis and pathophysiology of AFE.

  2. Velopharyngeal sphincter pathophysiologic aspects in the in cleft palat

    Directory of Open Access Journals (Sweden)

    Collares, Marcus Vinicius Martins

    2008-09-01

    Full Text Available Introduction: Cleft lip and palate are common congenital abnormalities with typical functional disorders on speech, deglutition and middle ear function. Objective: This article reviews functional labiopalatine disorders through a pathophysiological view. Method: We performed a literature search on line, as well as books and periodicals related to velopharyngeal sphincter. Our sources were LILACS, MEDLINE and SciELO databases, and we applied to the research Keywords of interest on the velopharyngeal pathophysiology, for articles published between 1965 and 2007. Conclusion: Velopharyngeal sphincter plays a central role in speech, swallowing and middle ear physiology in patients with labiopalatine cleft. At the end of our bibliographic review, pursuant to the velopharyngeal physiology in individuals with this disorder in the functional speech, deglutition and otologic function, we observed that although there is a great number of published data discussing this issue, further studies are necessary to completely understand the pathophysiology, due to the fact they have been exploited superficially.

  3. The stability of the bifluoride ion (HF - 2) in the gas phase

    Science.gov (United States)

    Heni, Martin; Illenberger, Eugen

    1985-12-01

    The bifluoride ion (HF-2) has been generated by dissociative electron attachment to trans-1,2-difluorethylene and cis-1,2-difluoroethylene. Evaluation of the energetics for these reactions leads to ΔH0f (HF-2) ≤-6.9 eV and E. A. (HF2)≥4.8 eV.

  4. Photon strength function in the Hf-181 nucleus by method of two-step cascade

    CERN Document Server

    Le Hong Khiem

    2003-01-01

    The applicability of sum-coincidence measurements of two-step cascade gamma ray spectra determining Photon Strength Function (PSF) of Hf-181 induced from Hf-180 (n,2 gamma) Hf-181 reaction is presented. Up to 80% intensity of the primary gamma ray transitions in a wide energy range have been deduced and compared to model calculation.

  5. 40 CFR 180.1273 - Beauveria bassiana HF23; exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Beauveria bassiana HF23; exemption... FOOD Exemptions From Tolerances § 180.1273 Beauveria bassiana HF23; exemption from the requirement of a tolerance. Residues of Beauveria bassiana HF23 are exempt from the requirement of a tolerance on all...

  6. Synthesis of Tetragonal and Orthorhombic Polymorphs of Hf3N4 by High-Pressure Annealing of a Prestructured Nanocrystalline Precursor

    Science.gov (United States)

    2013-01-01

    Hf3N4 in nanocrystalline form is produced by solution phase reaction of Hf(NEtMe)4 with ammonia followed by low-temperature pyrolysis in ammonia. Understanding of phase behavior in these systems is important because early transition-metal nitrides with the metal in maximum oxidation state are potential visible light photocatalysts. A combination of synchrotron powder X-ray diffraction and pair distribution function studies has been used to show this phase to have a tetragonally distorted fluorite structure with 1/3 vacancies on the anion sites. Laser heating nanocrystalline Hf3N4 at 12 GPa and 1500 K in a diamond anvil cell results in its crystallization with the same structure type, an interesting example of prestructuring of the phase during preparation of the precursor compound. This metastable pathway could provide a route to other new polymorphs of metal nitrides and to nitrogen-rich phases where they do not currently exist. Importantly it leads to bulk formation of the material rather than surface conversion as often occurs in elemental combination reactions at high pressure. Laser heating at 2000 K at a higher pressure of 19 GPa results in a further new polymorph of Hf3N4 that adopts an anion deficient cottunite-type (orthorhombic) structure. The orthorhombic Hf3N4 phase is recoverable to ambient pressure and the tetragonal phase is at least partially recoverable. PMID:23721167

  7. PATHOPHYSIOLOGY STROKE NON-HEMORRHAGIC ET CAUSA THROMBUS

    Directory of Open Access Journals (Sweden)

    Aji Kristianto Wijaya

    2013-10-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE Stroke is one of the most common cause of death worldwide and the third leading cause of death in the United States. Stroke composed 90,000 deaths of women and 60,000 men each year. In Indonesia, 8 of 1000 people suffered a stroke. Stroke is divided into two, non-hemorrhagic stroke and hemorrhagic stroke. Most of them (80% is non-hemorrhagic stroke. Non-hemorrhagic stroke can be caused by thrombi or emboli. Understanding the pathophysiology of non-hemorrhagic stroke caused by a thrombus is very important in regard with providing appropriate patient management. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  8. Quantitative imaging of basic functions in renal (patho)physiology.

    Science.gov (United States)

    Kang, Jung Julie; Toma, Ildiko; Sipos, Arnold; McCulloch, Fiona; Peti-Peterdi, Janos

    2006-08-01

    Multiphoton fluorescence microscopy offers the advantages of deep optical sectioning of living tissue with minimal phototoxicity and high optical resolution. More importantly, dynamic processes and multiple functions of an intact organ can be visualized in real time using noninvasive methods, and quantified. These studies aimed to extend existing methods of multiphoton fluorescence imaging to directly observe and quantify basic physiological parameters of the kidney including glomerular filtration rate (GFR) and permeability, blood flow, urinary concentration/dilution, renin content and release, as well as more integrated and complex functions like the tubuloglomerular feedback (TGF)-mediated oscillations in glomerular filtration and tubular flow. Streptozotocin-induced diabetes significantly increased single-nephron GFR (SNGFR) from 32.4 +/- 0.4 to 59.5 +/- 2.5 nl/min and glomerular permeability to a 70-kDa fluorophore approximately eightfold. The loop diuretic furosemide 2-fold diluted and increased approximately 10-fold the volume of distal tubular fluid, while also causing the release of 20% of juxtaglomerular renin content. Significantly higher speeds of individual red blood cells were measured in intraglomerular capillaries (16.7 +/- 0.4 mm/s) compared with peritubular vessels (4.7 +/- 0.2 mm/s). Regular periods of glomerular contraction-relaxation were observed, resulting in oscillations of filtration and tubular flow rate. Oscillations in proximal and distal tubular flow showed similar cycle times ( approximately 45 s) to glomerular filtration, with a delay of approximately 5-10 and 25-30 s, respectively. These innovative technologies provide the most complex, immediate, and dynamic portrayal of renal function, clearly depicting the components and mechanisms involved in normal physiology and pathophysiology.

  9. Sarcopenia and functional decline: pathophysiology, prevention and therapy.

    Science.gov (United States)

    Bautmans, Ivan; Van Puyvelde, Katrien; Mets, Tony

    2009-01-01

    Twenty years ago, the term 'sarcopenia' has been introduced to describe the ageing related loss of skeletal muscle mass. Since then, sarcopenia has been intensively studied and prevalence values have been reported in fifteen papers covering several continents and races. However, consistency regarding the outcome measures and corresponding cut-off values defining sarcopenia is lacking. Most approaches are based on estimations of muscle mass and proposed cut-off values might be too strict, thus reducing their use in daily practice. From a clinical viewpoint, the assessment of muscle performance (grip strength and endurance) can be proposed as a screening tool showing sufficient sensitivity. The pathophysiology of sarcopenia is multifactorial, and important changes at the tissue level have been identified. Close relationships with inflammatory processes have been demonstrated and there is strong evidence for the involvement of a chronic low-grade inflammatory activity. Sarcopenia is aggravated by a complex interaction of several factors among which aging, disuse, immobilization, disease and malnutrition. A comprehensive geriatric assessment should allow the clinician to estimate the relative contribution of these factors and to elaborate appropriate management. From all interventions studied, intensive resistance training seems the most efficient to counter sarcopenia, even in the very old geriatric patients. Significant ameliorations (up to >50% strength gain) can be expected after six weeks of training at a rhythm of 2-3 sessions per week. From a preventive viewpoint, all elderly patients should be advised to start such an exercise program and continue it as long as possible. To date, most pharmacological interventions to counter sarcopenia include drugs with anabolic effects. Unfortunately, their effect is questionable and no clear guidelines exist for the prescription of these products in the context of sarcopenia.

  10. Histamine: metabolism, physiology, and pathophysiology with applications in veterinary medicine.

    Science.gov (United States)

    Peters, Lisa J; Kovacic, Jan P

    2009-08-01

    To review the human and veterinary literature on histamine physiology and pathophysiology and potential applications for clinical use in veterinary critical care. Human and veterinary clinical studies, reviews, texts, and recent research in histamine receptor and antagonist therapy. Recent progress in molecular biology has led to a more complete understanding of the enzymes involved in histamine metabolism and histamine receptor physiology. The past decade of research has confirmed the role of histamine in the classical functions (contraction of smooth muscle, increase in vascular permeability, and stimulation of gastric acid secretion) and has also elucidated newer ones that are now under investigation. Data on the roles of histamine in angiogenesis, circadian rhythm, bone marrow regeneration, bacterial eradication, and cancer are emerging in the literature. Newer histamine antagonists are currently in drug trials and are expected to advance the clinical field in treatment of allergic, gastrointestinal, and cognitive disorders. Veterinary histamine research is directed at identifying the effects of certain pharmacological agents on blood histamine concentrations and establishing the relevance in clinical disease states. Research demonstrates important species differences in regards to histamine receptor physiology and tissue response. Studies in the area of trauma, sepsis, anaphylaxis, allergy, and gastrointestinal disorders have direct applications to clinical veterinary medicine. Histamine plays a key role in the morbidity and mortality associated with allergy, asthma, gastric ulcers, anaphylaxis, sepsis, hemorrhagic shock, anesthesia, surgery, cardiovascular disease, cancer, CNS disorders, and immune-mediated disease. Histamine antagonism has been in common use to block its adverse effects. With recent advances in the understanding of histamine receptor physiology, pharmaceutical agents targeting these receptors have increased the therapeutic options.

  11. Pathophysiology of fistula formation in Crohn’s disease

    Institute of Scientific and Technical Information of China (English)

    Michael; Scharl; Gerhard; Rogler

    2014-01-01

    Fistulae represent an important complication in patient suffering from Crohn’s disease(CD). Cumulative incidence of fistula formation in CD patients is 17%-50% and about one third of patients suffer from recurring fistulae formation. Medical treatment options often fail and also surgery frequently is not successful. Available data indicate that CD-associated fistulae originate from an epithelial defect that may be caused by ongoing inflammation. Having undergone epithelial to mesenchymal transition(EMT), intestinal epithelial cells(IEC) penetrate into deeper layers of the mucosa and the gut wall causing localized tissue damage formation of a tube like structure and finally a connection to other organs or the body surface. EMT of IEC may be initially aimed toimprove wound repair mechanisms since "conventional" wound healing mechanisms, such as migration of fibroblasts, are impaired in CD patients. EMT also enhances activation of matrix remodelling enzymes such as matrix metalloproteinase(MMP)-3 and MMP-9 causing further tissue damage and inflammation. Finally, soluble mediators like TNF and interleukin-13 further induce their own expression in an autocrine manner and enhance expression of molecules associated with cell invasiveness aggravating the process. Additionally, pathogen-associated molecular patterns also seem to play a role for induction of EMT and fistula development. Though current knowledge suggests a number of therapeutic options, new and more effective therapeutic approaches are urgently needed for patients suffering from CD-associated fistulae. A better understanding of the pathophysiology of fistula formation, however, is a prerequisite for the development of more efficacious medical anti-fistula treatments.

  12. Mycotoxins in pathophysiology of cattle diet

    Directory of Open Access Journals (Sweden)

    Mašić Zoran

    2003-01-01

    Full Text Available Depending on the age and production category, cattle show different sensitivity towards certain mycotoxins. Microflora of the rumen degrades to a different degree and inactivates mycotoxins. In the work are presented the most important mycotoxicoses of cattle caused by fungal metabolites from the genera Fusarium, Aspergillus and Penicillium. Poisoning of cattle in our area is most often caused by Zearalenone, Dioxinivalenol, T-2 toxin, Ochratoxin A and Aflatoxin, but in the work are also presented Fumonisin B1 and B2. The work also describes preventive possibilities and protection of animal health from the effects of mycotoxins.

  13. The chronobiology, etiology and pathophysiology of obesity

    OpenAIRE

    M. Garaulet; Ordovás, JM; Madrid, JA

    2010-01-01

    The effect of CD on human health is an emerging issue. Many records link CD with diseases such as cancer, cardiovascular, cognitive impairment and obesity, all of them conducive to premature aging. The amount of sleep has declined by 1.5 h over the past century, accompanied by an important increase in obesity. Shift work, sleep deprivation and exposure to bright light at night increase the prevalence of adiposity. Animal models have shown that mice with Clock gene disruption are prone to deve...

  14. Two-dimensional semiconductor HfSe{sub 2} and MoSe{sub 2}/HfSe{sub 2} van der Waals heterostructures by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Aretouli, K. E.; Tsipas, P.; Tsoutsou, D.; Marquez-Velasco, J.; Xenogiannopoulou, E.; Giamini, S. A.; Vassalou, E.; Kelaidis, N.; Dimoulas, A., E-mail: a.dimoulas@inn.demokritos.gr [Institute of Nanoscience and Nanotechnology, National Center for Scientific Research “Demokritos,” 15310, Aghia Paraskevi, Athens (Greece)

    2015-04-06

    Using molecular beam epitaxy, atomically thin 2D semiconductor HfSe{sub 2} and MoSe{sub 2}/HfSe{sub 2} van der Waals heterostructures are grown on AlN(0001)/Si(111) substrates. Details of the electronic band structure of HfSe{sub 2} are imaged by in-situ angle resolved photoelectron spectroscopy indicating a high quality epitaxial layer. High-resolution surface tunneling microscopy supported by first principles calculations provides evidence of an ordered Se adlayer, which may be responsible for a reduction of the measured workfunction of HfSe{sub 2} compared to theoretical predictions. The latter reduction minimizes the workfunction difference between the HfSe{sub 2} and MoSe{sub 2} layers resulting in a small valence band offset of only 0.13 eV at the MoSe{sub 2}/HfSe{sub 2} heterointerface and a weak type II band alignment.

  15. Optical diffraction tomography techniques for the study of cell pathophysiology

    CERN Document Server

    Kim, Kyoohyun; Shin, Seungwoo; Lee, SangYun; Yang, Su-A; Park, YongKeun

    2016-01-01

    Three-dimensional imaging of biological cells is crucial for the investigation of cell biology, provide valuable information to reveal the mechanisms behind pathophysiology of cells and tissues. Recent advances in optical diffraction tomography (ODT) have demonstrated the potential for the study of various cells with its unique advantages of quantitative and label-free imaging capability. To provide insight on this rapidly growing field of research and to discuss its applications in biology and medicine, we present the summary of the ODT principle and highlight recent studies utilizing ODT with the emphasis on the applications to the pathophysiology of cells.

  16. Research progress of pathophysiological concepts in cerebral small vessel disease

    Directory of Open Access Journals (Sweden)

    Zai-qiang ZHANG

    2016-11-01

    Full Text Available The current definition of cerebral small vessels refers to all vascular structures ranging from 5 μ m to 2 mm in diameter in the brain parenchyma and they encompass small arteries, arterioles, capillaries, venules and small veins. Different diameters of cerebral small vessels have different distribution, and predilection to different types of pathophysiological process. Cerebral small vessel disease (cSVD, including lacunar infarct (LACI, white matter hyperintensity (WMH and cerebral microbleeds (CMBs, have different pathophysiological mechanisms and risk factors. Arterial stiffness is independently associated with all components of cSVD. DOI: 10.3969/j.issn.1672-6731.2016.11.007

  17. New insights into the pathophysiology of postoperative cognitive dysfunction

    DEFF Research Database (Denmark)

    Krenk, Lene; Rasmussen, Lars Simon; Kehlet, H

    2010-01-01

    There is evidence that postoperative cognitive dysfunction (POCD) is a significant problem after major surgery, but the pathophysiology has not been fully elucidated. The interpretation of available studies is difficult due to differences in neuropsychological test batteries as well as the lack...... of appropriate controls. Furthermore, there are no internationally accepted criteria for defining POCD. This article aims to provide an update of current knowledge of the pathogenesis of POCD with a focus on perioperative pathophysiology and possible benefits achieved from an enhanced postoperative recovery...

  18. Podcasts and videostreaming: Useful tools to facilitate learning of pathophysiology in undergraduate nurse education?

    Science.gov (United States)

    McKinney, Aidín A; Page, Karen

    2009-11-01

    Nurses require an understanding of pathophysiological processes to support safe practice in the clinical area. A review of the literature indicates that nursing students have traditionally found this to be a challenging element of the course. The increasing availability of newer technology in higher education such as videostreaming and podcasting provides the opportunity to utilise a variety of approaches to cater for a wider range of learning styles. In view of this, lecturers developed multimedia resources to incorporate into a pathophysiology module. An evaluation of students' views on the use of ICT to facilitate understanding of pathophysiology was undertaken. The majority of students appeared to welcome the incorporation of alternative teaching approaches into the module. Interestingly despite the opportunities which technology offers to enhance learning many of the students also highlighted the importance of maintaining significant face-to-face contact with lecturers. This supports the findings of the literature which indicates that students find hybrid learning strategies that combine traditional teaching with more innovative methods particularly beneficial.

  19. A review on Alzheimer's disease pathophysiology and its management: an update.

    Science.gov (United States)

    Kumar, Anil; Singh, Arti; Ekavali

    2015-04-01

    Alzheimer's disease acknowledged as progressive multifarious neurodegenerative disorder, is the leading cause of dementia in late adult life. Pathologically it is characterized by intracellular neurofibrillary tangles and extracellular amyloidal protein deposits contributing to senile plaques. Over the last two decades, advances in the field of pathogenesis have inspired the researchers for the investigation of novel pharmacological therapeutics centered more towards the pathophysiological events of the disease. Currently available treatments i.e. acetylcholinesterase inhibitors (rivastigmine, galantamine, donepezil) and N-methyl d-aspartate receptor antagonist (memantine) contribute minimal impact on the disease and target late aspects of the disease. These drugs decelerate the progression of the disease, provide symptomatic relief but fail to achieve a definite cure. While the neuropathological features of Alzheimer's disease are recognized but the intricacies of the mechanism have not been clearly defined. This lack of understanding regarding the pathogenic process may be the likely reason for the non-availability of effective treatment which can prevent onset and progression of the disease. Owing to the important progress in the field of pathophysiology in the last couple of years, new therapeutic targets are available that should render the underlying disease process to be tackled directly. In this review, authors will discusses the different aspects of pathophysiological mechanisms behind Alzheimer's disease and its management through conventional drug therapy, including modern investigational therapeutic strategies, recently completed and ongoing. Copyright © 2014 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  20. Pathophysiology of pulmonary complications of acute pancreatitis

    Institute of Scientific and Technical Information of China (English)

    George W Browne; CS Pitchurnoni

    2006-01-01

    Acute pancreatitis in its severe form is complicated by multiple organ system dysfunction, most importantly by pulmonary complications which include hypoxia,acute respiratory distress syndrome, atelectasis, and pleural effusion. The pathogenesis of some of the above complications is attributed to the production of noxious cytokines. Clinically significant is the early onset of pleural effusion, which heralds a poor outcome of acute pancreatitis. The role of circulating trypsin, phospholipase A2, platelet activating factor, release of free fatty acids,chemoattractants such as tumor necrsosis factor (TNF)-alpha, interleukin (IL)-1, IL-6, IL-8, fMet-leu-phe (a bacterial wall product), nitric oxide, substance P, and macrophage inhibitor factor is currently studied. The hope is that future management of acute pancreatitis with a better understanding of the pathogenesis of lung injury will be directed against the production of noxious cytokines.

  1. [Pathophysiological implications of the chemical messengers].

    Science.gov (United States)

    Blázquez Fernández, Enrique

    2009-01-01

    To maintain a physical organization and a different composition of its surroundings environment, living beings use a great part of the energy that they produce. Vital processes require an elevated number of reactions which are regulated and integrated by chemical messengers. They use autocrine, paracrine, endocrine and synaptic signals through receptors of cell surface, nuclear or associated with ionic chanels, enzymes, trimeric G proteins and to intracellular kinases. Through these mechanisms pheromones play an important role in the relationships between different individuals, and hormones are able to regulate the integrative functions of our organism. In the nervous system, neurotransmitters, neuromodulators, sensors and receptors between other messengers, play functions of great relevance, while growth factors stimulate cell proliferation and cytokines have many effects but the most important is the ones related with the control of the immflamatory process. Alterations of these messengers permit us a better understanding of the diseases and possibly of its treatments in a near future. Modifications of the expression of genes from the nuclear and mitochondrial genomas are responsible of monogenic, polygenic and mitochondrial diseases, while alterations in the activities of dopamine and serotonin neurotransmitters are related with schizophrenia, Parkinson disease and depression, respectively. Other example is the hyperthyroidism of the Graves-Bassedow disease due to the competitive interference of the LATS immunoglobulin with TSH at the level of the folicular cells producing thyroid hormones Twenty five years ago in the reviews on the mechanisms of insulin action, there was presentations in which the insulin receptor was located in the plasma membrane of the target cells while in the cytoplasm only a big interrogative was observed, that at present is replaced by chemical mediators cascades responsible of the multiple effects of insulin. This finding is similar to

  2. Detrital zircon evidence for Hf isotopic evolution of granitoid crust and continental growth

    Science.gov (United States)

    Iizuka, Tsuyoshi; Komiya, Tsuyoshi; Rino, Shuji; Maruyama, Shigenori; Hirata, Takafumi

    2010-04-01

    We have determined U-Pb ages, trace element abundances and Hf isotopic compositions of approximately 1000 detrital zircon grains from the Mississippi, Congo, Yangtze and Amazon Rivers. The U-Pb isotopic data reveal the lack of >3.3 Ga zircons in the river sands, and distinct peaks at 2.7-2.5, 2.2-1.9, 1.7-1.6, 1.2-1.0, 0.9-0.4, and uniformitarian secular change in Hf isotopes of granitoid crusts; Hf isotopic compositions of granitoid crusts deviate from the mantle evolution line from about 3.3 to 2.0 Ga, the deviation declines between 2.0 and 1.3 Ga and again increases afterwards. Consideration of mantle-crust mixing models for granitoid genesis suggests that the noted isotopic trends are best explained if the rate of crust generation globally increased in two stages at around (or before) 3.3 and 1.3 Ga, whereas crustal differentiation was important in the evolution of the continental crust at 2.3-2.2 Ga and after 0.6 Ga. Reconciling the isotopic secular change in granitoid crust with that in sedimentary rocks suggests that sedimentary recycling has essentially taken place in continental settings rather than active margin settings and that the sedimentary mass significantly grew through addition of first-cycle sediments from young igneous basements, until after ˜1.3 Ga when sedimentary recycling became the dominant feature of sedimentary evolution. These findings, coupled with the lack of zircons older than 3.3 Ga in river sands, imply the emergence of large-scale continents at about 3.3 Ga with further rapid growth at around 1.3 Ga. This resulted in the major growth of the sedimentary mass between 3.3 and 1.3 Ga and the predominance of its cannibalistic recycling later.

  3. Pathophysiology and treatment of psychosis in Parkinson's disease: a review.

    Science.gov (United States)

    Zahodne, Laura B; Fernandez, Hubert H

    2008-01-01

    Psychotic symptoms in Parkinson's disease (PD) are relatively common and, in addition to creating a disturbance in patients' daily lives, have consistently been shown to be associated with poor outcome. Our understanding of the pathophysiology of psychosis in PD has expanded dramatically over the past 15 years, from an initial interpretation of symptoms as dopaminergic drug adverse effects to the current view of a complex interplay of extrinsic and disease-related factors.PD psychosis has unique clinical features, namely that it arises within a context of a clear sensorium and retained insight, there is relative prominence of visual hallucinations and progression occurs over time. PD psychosis tends to emerge later in the disease course, and disease duration represents one risk factor for its development. The use of anti-PD medications (particularly dopamine receptor agonists) has been the most widely identified risk factor for PD psychosis. Other risk factors discussed in the literature include older age, disease severity, sleep disturbance, cognitive impairment, dementia and/or depression.Recent efforts have aimed to explore the complex pathophysiology of PD psychosis, which is now known to involve an interaction between extrinsic, drug-related and intrinsic, disease-related components. The most important extrinsic factor is use of dopaminergic medication, which plays a prominent role in PD psychosis. Intrinsic factors include visual processing deficits (e.g. lower visual acuity, colour and contrast recognition deficits, ocular pathology and functional brain abnormalities identified amongst hallucinating PD patients); sleep dysregulation (e.g. sleep fragmentation and altered dream phenomena); neurochemical (dopamine, serotonin, acetylcholine, etc.) and structural abnormalities involving site-specific Lewy body deposition; and genetics (e.g. apolipoprotein E epsilon4 allele and tau H1H1 genotype). Preliminary reports have also shown a potential relationship

  4. Charge storage characteristics and tunneling mechanism of amorphous Ge-doped HfOx films

    Science.gov (United States)

    Qiu, X. Y.; Zhang, S. Y.; Zhang, T.; Wang, R. X.; Li, L. T.; Zhang, Y.; Dai, J. Y.

    2016-09-01

    Amorphous Ge-doped HfOx films have been deposited on p-Si(100) substrates by means of RF magnetron sputtering. Microstructural investigations reveal the partial oxidation of doped Ge atoms in the amorphous HfOx matrix and the existence of HfSiOx interfacial layer. Capacitance-voltage hysteresis of the Ag-/Ge-doped HfOx/Si/Ag memory capacitor exhibits a memory window of 3.15 V which can maintain for >5 × 104 cycles. Current-voltage characteristics reveal that Poole-Frenkel tunneling is responsible for electron transport in the Ge-doped HfOx film.

  5. Bile acids: Chemistry, physiology, and pathophysiology

    Institute of Scientific and Technical Information of China (English)

    Maria J Monte; Jose JG Marin; Alvaro Antelo; Jose Vazquez-Tato

    2009-01-01

    The family of bile acids includes a group of molecular species of acidic steroids with very peculiar physicalchemical and biological characteristics. They are synthesized by the liver from cholesterol through several complementary pathways that are controlled by mechanisms involving fine-tuning by the levels of certain bile acid species. Although their bestknown role is their participation in the digestion and absorption of fat, they also play an important role in several other physiological processes. Thus, genetic abnormalities accounting for alterations in their synthesis, biotransformation and/or transport may result in severe alterations, even leading to lethal situations for which the sole therapeutic option may be liver transplantation. Moreover, the increased levels of bile acids reached during cholestatic liver diseases are known to induce oxidative stress and apoptosis, resulting in damage to the liver parenchyma and, ventually, extrahepatic tissues. When this occurs during pregnancy, the outcome of gestation may be challenged. In contrast, the physical-chemical and biological properties of these compounds have been used as the bases for the development of drugs and as pharmaceutical tools for the delivery of active agents.

  6. [Adrenomedullin in the kidney: physiology and pathophysiology].

    Science.gov (United States)

    Sogbe-Díaz, Miguel Eduardo; Díaz-López, Emilia Elena

    2016-03-01

    Adrenomedullin (AM) is a potent vasodilatory 52-aminoacid peptide hormone, ubiquitous with multiple physiological effects which contribute to homeostatic responses. Significantly, it is distributed in the adrenal gland, lung, cardiovascular and renal system. The biological effects of AM are directly mediated by specific receptors as heterodimers composed of the calcitonin-receptor-like receptor (CLR) and one of two receptor activity modifying proteins (RAMP2 or RAMP3). The CLR/RAMP2 (AM1 receptor) is more highly AM-specific than The CLR/RAMP3 (AM2 receptor). Plasma levels of AM are elevated proportionately to the increase in blood pressure and degree of renal damage in patients with hypertension; likewise, these levels are correlated with the degree ofheart and arterial hypertrophy. AM has renal vasodilatory, natriuretic and diuretic actions; increased glomerular filtration rate and renal blood flow. AM inhibits proliferation and reactive oxygen species generation in mesangial cells; also inhibits aldosterone secretion in the zona glomerulosa and endothelin-1 in vascular smooth muscle cells. Therefore, it is proposed as a new marker in various diseases, especially chronic renal failure. This disease presents compensatory hypertrophy of the glomeruli and mesangial proliferation, administration of AM reduces the levels of proteinuria, suggesting that AM has an important modulator role in blood pressure and could be a therapeutic option for chronic renal failure.

  7. Hypertension in Metabolic Syndrome: Vascular Pathophysiology

    Directory of Open Access Journals (Sweden)

    Yolanda Mendizábal

    2013-01-01

    Full Text Available Metabolic syndrome is a cluster of metabolic and cardiovascular symptoms: insulin resistance (IR, obesity, dyslipemia. Hypertension and vascular disorders are central to this syndrome. After a brief historical review, we discuss the role of sympathetic tone. Subsequently, we examine the link between endothelial dysfunction and IR. NO is involved in the insulin-elicited capillary vasodilatation. The insulin-signaling pathways causing NO release are different to the classical. There is a vasodilatory pathway with activation of NO synthase through Akt, and a vasoconstrictor pathway that involves the release of endothelin-1 via MAPK. IR is associated with an imbalance between both pathways in favour of the vasoconstrictor one. We also consider the link between hypertension and IR: the insulin hypothesis of hypertension. Next we discuss the importance of perivascular adipose tissue and the role of adipokines that possess vasoactive properties. Finally, animal models used in the study of vascular function of metabolic syndrome are reviewed. In particular, the Zucker fatty rat and the spontaneously hypertensive obese rat (SHROB. This one suffers macro- and microvascular malfunction due to a failure in the NO system and an abnormally high release of vasoconstrictor prostaglandins, all this alleviated with glitazones used for metabolic syndrome therapy.

  8. Therapy of rheumatic polymyalgia: the pathophysiologic management

    Directory of Open Access Journals (Sweden)

    M.A. Cimino

    2011-09-01

    Full Text Available Polymyalgia rheumatica (PMR is an inflammatory syndrome affecting older people whose prevalence has increased in recent years. The suppression of the hypothalamic-pituitary-adrenal axis (HPA and ageing may contribute to the pathogenesis of PMR. Chronic stress (i.e. interpersonal, chronic infections etc. in elderly people may represent a risk factor for the development of PMR. In fact, elderly represent per se a condition of endocrine senescence including adrenal hypofunction, in addition chronic stress represents a further harmful stimulus to seriously compromise endogenous glucocorticoid production. Synovitis and vasculitis characterize the majority of the patients. Serum cytokine and steroidal hormone patterns suggest that patients with PMR have an intensive inflammatory reaction. As a matter of fact, glucocorticoids represent the most useful temporary “replacement” treatment during the active phase of PMR. The use of modified-release glucocorticoids that might induce higher levels during the night (circadian rhythms as in physiological conditions, will represent another important approach to optimize PMR treatment and reduce the side effects. Combination therapy between glucocorticoids and inhibitors of pro-inflammatory cytokines should be tested in large studies and early cases of PMR.

  9. Pathophysiology and prevention of postoperative peritoneal adhesions

    Institute of Scientific and Technical Information of China (English)

    Willy Arung1; Michel Meurisse; Olivier Detry

    2011-01-01

    Peritoneal adhesions represent an important clinical challenge in gastrointestinal surgery. Peritoneal adhesions are a consequence of peritoneal irritation by infection or surgical trauma, and may be considered as the pathological part of healing following any peritoneal injury, particularly due to abdominal surgery. The balance between fibrin deposition and degradation is critical in determining normal peritoneal healing or adhesion formation. Postoperative peritoneal adhesions are a major cause of morbidity resulting in multiple complications, many of which may manifest several years after the initial surgical procedure. In addition to acute small bowel obstruction, peritoneal adhesions may cause pelvic or abdominal pain, and infertility. In this paper, the authors reviewed the epidemiology, pathogenesis and various prevention strategies of adhesion formation, using Medline and PubMed search. Several preventive agents against postoperative peritoneal adhesions have been investigated. Their role aims in activating fibrinolysis, hampering coagulation, diminishing the inflammatory response, inhibiting collagen synthesis or creating a barrier between adjacent wound surfaces. Their results are encouraging but most of them are contradictory and achieved mostly in animal model. Until additional findings from future clinical researches, only a meticulous surgery can be recommended to reduce unnecessary morbidity and mortality rates from these untoward effects of surgery. In the current state of knowledge, pre-clinical or clinical studies are still necessary to evaluate the effectiveness of the several proposed prevention strategies of postoperative peritoneal adhesions.

  10. Diabetic Macular Edema Pathophysiology: Vasogenic versus Inflammatory

    Directory of Open Access Journals (Sweden)

    Pedro Romero-Aroca

    2016-01-01

    Full Text Available Diabetic macular edema (DME can cause blindness in diabetic patients suffering from diabetic retinopathy (DR. DM parameters controls (glycemia, arterial tension, and lipids are the gold standard for preventing DR and DME. Although the vascular endothelial growth factor (VEGF is known to play a role in the development of DME, the pathological processes leading to the onset of this disease are highly complex and the exact sequence in which they occur is still not completely understood. Angiogenesis and inflammation have been shown to be involved in the pathogenesis of this disease. However, it still remains to be clarified whether angiogenesis following VEGF overexpression is a cause or a consequence of inflammation. This paper provides a review of the data currently available, focusing on VEGF, angiogenesis, and inflammation. Our analysis suggests that angiogenesis and inflammation act interdependently during the development of DME. Knowledge of DME etiology seems to be important in treatments with anti-VEGF or anti-inflammatory drugs. Current diagnostic techniques do not permit us to differentiate between both etiologies. In the future, diagnosing the physiopathology of each patient with DME will help us to select the most effective drug.

  11. Diabetic Macular Edema Pathophysiology: Vasogenic versus Inflammatory

    Science.gov (United States)

    Baget-Bernaldiz, Marc; Pareja-Rios, Alicia; Lopez-Galvez, Maribel; Navarro-Gil, Raul; Verges, Raquel

    2016-01-01

    Diabetic macular edema (DME) can cause blindness in diabetic patients suffering from diabetic retinopathy (DR). DM parameters controls (glycemia, arterial tension, and lipids) are the gold standard for preventing DR and DME. Although the vascular endothelial growth factor (VEGF) is known to play a role in the development of DME, the pathological processes leading to the onset of this disease are highly complex and the exact sequence in which they occur is still not completely understood. Angiogenesis and inflammation have been shown to be involved in the pathogenesis of this disease. However, it still remains to be clarified whether angiogenesis following VEGF overexpression is a cause or a consequence of inflammation. This paper provides a review of the data currently available, focusing on VEGF, angiogenesis, and inflammation. Our analysis suggests that angiogenesis and inflammation act interdependently during the development of DME. Knowledge of DME etiology seems to be important in treatments with anti-VEGF or anti-inflammatory drugs. Current diagnostic techniques do not permit us to differentiate between both etiologies. In the future, diagnosing the physiopathology of each patient with DME will help us to select the most effective drug.

  12. Lipodystrophy: pathophysiology and advances in treatment.

    Science.gov (United States)

    Fiorenza, Christina G; Chou, Sharon H; Mantzoros, Christos S

    2011-03-01

    Lipodystrophy is a medical condition characterized by complete or partial loss of adipose tissue. Not infrequently, lipodystrophy occurs in combination with pathological accumulation of adipose tissue at distinct anatomical sites. Patients with lipodystrophy exhibit numerous metabolic complications, which indicate the importance of adipose tissue as an active endocrine organ. Not only the total amount but also the appropriate distribution of adipose tissue depots contribute to the metabolic state. Genetic and molecular research has improved our understanding of the mechanisms underlying lipodystrophy. Circulating levels of hormones secreted by the adipose tissue, such as leptin and adiponectin, are greatly reduced in distinct subpopulations of patients with lipodystrophy. This finding rationalizes the use of these adipokines or of agents that increase their circulating levels, such as peroxisome proliferator-activated receptor γ (PPARγ) agonists, for therapeutic purposes. Other novel therapeutic approaches, including the use of growth hormone and growth-hormone-releasing factors, are also being studied as potential additions to the therapeutic armamentarium. New insights gained from research and clinical trials could potentially revolutionize the management of this difficult-to-treat condition.

  13. [Gut microbiota: Description, role and pathophysiologic implications].

    Science.gov (United States)

    Landman, C; Quévrain, E

    2016-06-01

    The human gut contains 10(14) bacteria and many other micro-organisms such as Archaea, viruses and fungi. Studying the gut microbiota showed how this entity participates to gut physiology and beyond this to human health, as a real "hidden organ". In this review, we aimed to bring information about gut microbiota, its structure, its roles and its implication in human pathology. After bacterial colonization in infant, intestinal microbial composition is unique for each individual although more than 95% can be assigned to four major phyla. The use of culture independent methods and more recently the development of high throughput sequencing allowed to depict precisely gut microbiota structure and diversity as well as its alteration in diseases. Gut microbiota is implicated in the maturation of the host immune system and in many fundamental metabolic pathways including sugars and proteins fermentation and metabolism of bile acids and xenobiotics. Imbalance of gut microbial populations or dysbiosis has important functional consequences and is implicated in many digestive diseases (inflammatory bowel diseases, colorectal cancer, etc.) but also in obesity and autism. These observations have led to a surge of studies exploring therapeutics which aims to restore gut microbiota equilibrium such as probiotics or fecal microbiota transplantation. But recent research also investigates biological activity of microbial products which could lead to interesting therapeutics leads. Copyright © 2015 Société Nationale Française de Médecine Interne (SNFMI). Published by Elsevier SAS. All rights reserved.

  14. Islet Amyloid Polypeptide: Structure, Function, and Pathophysiology

    Directory of Open Access Journals (Sweden)

    Rehana Akter

    2016-01-01

    Full Text Available The hormone islet amyloid polypeptide (IAPP, or amylin plays a role in glucose homeostasis but aggregates to form islet amyloid in type-2 diabetes. Islet amyloid formation contributes to β-cell dysfunction and death in the disease and to the failure of islet transplants. Recent work suggests a role for IAPP aggregation in cardiovascular complications of type-2 diabetes and hints at a possible role in type-1 diabetes. The mechanisms of IAPP amyloid formation in vivo or in vitro are not understood and the mechanisms of IAPP induced β-cell death are not fully defined. Activation of the inflammasome, defects in autophagy, ER stress, generation of reactive oxygen species, membrane disruption, and receptor mediated mechanisms have all been proposed to play a role. Open questions in the field include the relative importance of the various mechanisms of β-cell death, the relevance of reductionist biophysical studies to the situation in vivo, the molecular mechanism of amyloid formation in vitro and in vivo, the factors which trigger amyloid formation in type-2 diabetes, the potential role of IAPP in type-1 diabetes, the development of clinically relevant inhibitors of islet amyloidosis toxicity, and the design of soluble, bioactive variants of IAPP for use as adjuncts to insulin therapy.

  15. Clinical trials update from the Heart Failure Society of America Meeting 2009: FAST, IMPROVE-HF, COACH galectin-3 substudy, HF-ACTION nuclear substudy, DAD-HF, and MARVEL-1.

    Science.gov (United States)

    Lainscak, Mitja; Coletta, Alison P; Sherwi, Nasser; Cleland, John G F

    2010-02-01

    This article presents findings and a commentary on late-breaking trials presented during the meeting of the Heart Failure Society of America in September 2009. Unpublished reports should be considered as preliminary, since analyses may change in the final publication. The FAST trial showed somewhat better performance of intrathoracic impedance for prediction of deterioration in patients with heart failure (HF) when compared with daily weighing. The IMPROVE-HF study reported the benefits of education on the management of patients with systolic HF. Galectin-3 appeared a useful method for improving risk stratification of patients with chronic HF in a substudy of the COACH trial. A nuclear substudy of the HF-ACTION trial failed to demonstrate that resting myocardial perfusion imaging, a measure of myocardial scar and viability, was clinically useful. A small randomized controlled trial (DAD-HF) suggested that the use of low-dose dopamine in patients with acutely decompensated HF was associated with less deterioration in renal function and less hypokalaemia. The MARVEL-1 trial raises further concerns about the safety of myoblast transplantation in ischaemic HF.

  16. The anisotropy of Hf diffusion in {alpha}-Zr

    Energy Technology Data Exchange (ETDEWEB)

    Hood, G.M. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.]|[Metals Technology Laboratory, CANMET, Ottawa, Ontario (Canada); Zou, H. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.]|[Metals Technology Laboratory, CANMET, Ottawa, Ontario (Canada); Roy, J.A. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.]|[Metals Technology Laboratory, CANMET, Ottawa, Ontario (Canada); Schultz, R.J. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.]|[Metals Technology Laboratory, CANMET, Ottawa, Ontario (Canada); Matsuura, N. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.]|[Metals Technology Laboratory, CANMET, Ottawa, Ontario (Canada); Jackman, J.A. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.]|[Metals Technology Laboratory, CANMET, Ottawa, Ontario (Canada)

    1996-02-01

    Hf diffusion coefficients (D) have been measured ({proportional_to}870-1100 K) in directions parallel (D{sub pa}) and perpendicular (D{sub pe}) to the c-axis of double-faced, single-crystal specimens of both high purity (HP) and nominally pure (NP) {alpha}-Zr. The diffusion profiles were measured by secondary ion mass spectrometry. Hf diffusion in HP {alpha}-Zr is characterised by an activation energy of about 3.0 eV and a pre-exponential factor of about 10{sup -5} m{sup 2}/s. The anisotropy ratio, D{sub pa}/D{sub pe}, is {proportional_to}<1.0 for the HP specimens and mostly >1.0 for the NP specimens. A dependence of D on diffusion time/depth is indicated for some experiments on NP Zr. (orig.).

  17. Generation of ionospheric ducts by the HAARP HF heater

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, J A; Pradipta, R; Burton, L M; Labno, A; Lee, M C [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Watkins, B J; Fallen, C [University of Alaska Fairbanks, Fairbanks, AK 99775 (United States); Kuo, S P [New York University, Brooklyn, NY 11201 (United States); Burke, W J [Air Force Research Laboratory, Hanscom AFB, MA 01731 (United States); Mabius, D; See, B Z, E-mail: mclee@mit.edu [Boston University, Boston, MA 02215 (United States)

    2010-12-15

    We report an investigation of ionospheric ducts having the shape of large plasma sheets, generated by vertically transmitted HAARP HF heater waves in several experiments conducted in Gakona, Alaska. Theory predicts that O-mode heater wave-created ionospheric ducts form parallel-plate waveguides within the meridional plane, and those generated by the X-mode heater waves are orthogonal to the meridional plane. Our theoretical prediction is supported by measurements of ionosonde data (namely ionograms), range-time-intensity (RTI) plots of UHF and HF backscatter radars, as well as magnetometer data analyses. When these plasma sheets experienced ExB drifts, they were intercepted by the HAARP UHF radar and seen as slanted stripes in the RTI plots. This striking feature was also observed in our earlier experiments using the Arecibo UHF radar.

  18. Use of GPS network data for HF Doppler measurements interpretation

    CERN Document Server

    Petrova, Inna R; Latypov, Ruslan R

    2014-01-01

    The method of measurement of Doppler frequency shift of ionospheric signal - HF Doppler technique - is one of well-known and widely used methods of ionosphere research. It allows to research various disturbances in the ionosphere. There are some sources of disturbances in the ionosphere. These are geomagnetic storms, solar flashes, metrological effects, atmospheric waves. This method allows to find out the influence of earthquakes, explosions and other processes on the ionosphere, which occur near to the Earth. HF Doppler technique has the high sensitivity to small frequency variations and the high time resolution, but interpretation of results is difficult. In this work we make an attempt to use GPS data for Doppler measurements interpretation. Modeling of Doppler frequency shift variations with use of TEC allows to separate ionosphere disturbances of medium scale.

  19. Imaging HF-induced large-scale irregularities above HAARP

    Science.gov (United States)

    Djuth, Frank T.; Reinisch, Bodo W.; Kitrosser, David F.; Elder, John H.; Snyder, A. Lee; Sales, Gary S.

    2006-02-01

    The University of Massachusetts-Lowell digisonde is used with the HAARP high-frequency (HF), ionospheric modification facility to obtain radio images of artificially-produced, large-scale, geomagnetic field-aligned irregularities. F region irregularities generated with the HAARP beam pointed in the vertical and geomagnetic field-aligned directions are examined in a smooth background plasma. It is found that limited large-scale irregularity production takes place with vertical transmissions, whereas there is a dramatic increase in the number of source irregularities with the beam pointed parallel to the geomagnetic field. Strong irregularity production appears to be confined to within ~5° of the geomagnetic zenith and does not fill the volume occupied by the HF beam. A similar effect is observed in optical images of artificial airglow.

  20. Performance Analysis of HF Band FB-MC-SS

    Energy Technology Data Exchange (ETDEWEB)

    Hussein Moradi; Stephen Andrew Laraway; Behrouz Farhang-Boroujeny

    2016-01-01

    Abstract—In a recent paper [1] the filter bank multicarrier spread spectrum (FB-MC-SS) waveform was proposed for wideband spread spectrum HF communications. A significant benefit of this waveform is robustness against narrow and partial band interference. Simulation results in [1] demonstrated good performance in a wideband HF channel over a wide range of conditions. In this paper we present a theoretical analysis of the bit error probably for this system. Our analysis tailors the results from [2] where BER performance was analyzed for maximum ration combining systems that accounted for correlation between subcarriers and channel estimation error. Equations are give for BER that closely match the simulated performance in most situations.

  1. Pathophysiology of acute mountain sickness and high altitude pulmonary oedema

    DEFF Research Database (Denmark)

    Sutton, J R; Lassen, N

    1979-01-01

    We review the evidence that acute mountain sickness (AMS) and high altitude pulmonary oedema (HAPO) occur together more often than is realized. We hypothesize that AMS and HAPO have a common pathophysiological basis: both are due to increased pressure and flow in the microcirculation, causing...

  2. Pathophysiology of Tonic Muscle Activation During Epileptic Seizures

    DEFF Research Database (Denmark)

    Beniczky, S.; Conradsen, Isa; Wolf, P.

    2011-01-01

    , quantitative analysis of the sEMG during the epileptic seizures has received surprisingly little attention. The aim of our study was to elucidate the pathophysiology of the tonic muscle activation during seizures. SEMG was recorded from the deltoid muscles, during 58 seizures from 18 patients (9...

  3. The role of autoantibodies in the pathophysiology of rheumatoid arthritis.

    Science.gov (United States)

    Derksen, V F A M; Huizinga, T W J; van der Woude, D

    2017-06-01

    Rheumatoid arthritis (RA) is an autoimmune disease characterized by joint inflammation. The presence of autoantibodies in the sera of RA patients has provided many clues to the underlying disease pathophysiology. Based on the presence of several autoantibodies like rheumatoid factor (RF), anti-citrullinated protein antibodies (ACPA), anti-carbamylated protein antibodies (anti-CarP), and more recently anti-acetylated protein antibodies RA can be subdivided into seropositive and seronegative disease. The formation of these autoantibodies is associated with both genetic and environmental risk factors for RA, like specific human leukocyte antigen (HLA) alleles and smoking. Autoantibodies can be detected many years before disease onset in a subset of patients, suggesting a sequence of events in which the first autoantibodies develop in predisposed hosts, before an inflammatory response ensues leading to clinically apparent arthritis. Research on the characteristics and effector functions of these autoantibodies might provide more insight in pathophysiological processes underlying arthritis in RA. Recent data suggests that ACPA might play a role in perpetuating inflammation once it has developed. Furthermore, pathophysiological mechanisms have been discovered supporting a direct link between the presence of ACPA and both bone erosions and pain in RA patients. In conclusion, investigating the possible pathogenic potential of autoantibodies might lead to improved understanding of the underlying pathophysiological processes in rheumatoid arthritis.

  4. Idiopathic Intracranial Hypertension – Pathophysiology Based on Case Series

    Directory of Open Access Journals (Sweden)

    Ljubisavljević Srdjan

    2016-09-01

    Full Text Available According to the definition, idiopathic intracranial hypertension (IIH is a pathological state characterized by an increase in intracranial pressure; however, there are no obvious intracranial pathological processes. The pathophysiology of this disorder is not clear, although there are many reports related to it.

  5. Pathophysiology and treatment of edema following femoropopliteal bypass surgery

    NARCIS (Netherlands)

    te Slaa, A.; Dolmans, D. E. J. G. J.; Ho, G. H.; Moll, F. L.; van der Laan, L.

    2012-01-01

    Substantial lower-limb edema affects the majority of patients who undergo peripheral bypass surgery. Edema has impairing effects on the microvascular and the macrovascular circulation, causes discomfort and might delay the rehabilitation process of the patient. However, the pathophysiology of this e

  6. The pathophysiology of essential tremor and Parkinson's tremor

    NARCIS (Netherlands)

    Helmich, R.C.G.; Toni, I.; Deuschl, G.; Bloem, B.R.

    2013-01-01

    We review recent evidence about the pathophysiology of essential tremor and tremor in Parkinson's disease. We believe that a network perspective is necessary to understand this common neurological symptom, and that knowledge of cerebral network dysfunction in tremor disorders will help to develop ne

  7. The Pathophysiology of Essential Tremor and Parkinson's Tremor

    NARCIS (Netherlands)

    Helmich, R.C.G.; Toni, I.; Deuschl, G.; Bloem, B.R.

    2013-01-01

    We review recent evidence about the pathophysiology of essential tremor and tremor in Parkinson's disease. We believe that a network perspective is necessary to understand this common neurological symptom, and that knowledge of cerebral network dysfunction in tremor disorders will help to develop ne

  8. Unravelling narcolepsy : from pathophysiology to measuring treatment effects

    NARCIS (Netherlands)

    Heide, van der A.

    2017-01-01

    Narcolepsy is a disorder of the regulation of sleep and wakefulness, with as its major features excessive daytime sleepiness (EDS), cataplexy, hypnagogic hallucinations, sleep paralysis and disturbed nocturnal sleep. The first part of this thesis concernes an overview of the pathophysiology,

  9. New insights into the pathophysiology of postoperative cognitive dysfunction

    DEFF Research Database (Denmark)

    Krenk, Lene; Rasmussen, Lars Simon; Kehlet, H

    2010-01-01

    There is evidence that postoperative cognitive dysfunction (POCD) is a significant problem after major surgery, but the pathophysiology has not been fully elucidated. The interpretation of available studies is difficult due to differences in neuropsychological test batteries as well as the lack o...... minimal invasive surgery, multi-modal non-opioid pain management and pharmacological manipulation of the inflammatory response and sleep architecture....

  10. Reverse Engineering Human Pathophysiology with Organs-on-Chips.

    Science.gov (United States)

    Ingber, Donald E

    2016-03-10

    While studies of cultured cells have led to new insights into biological control, greater understanding of human pathophysiology requires the development of experimental systems that permit analysis of intercellular communications and tissue-tissue interactions in a more relevant organ context. Human organs-on-chips offer a potentially powerful new approach to confront this long-standing problem.

  11. Epidemiology, Pathophysiology, and the Future of Ocular Toxoplasmosis

    NARCIS (Netherlands)

    Kijlstra, A.; Pedersen, E.

    2014-01-01

    Despite large advances in the field of ocular toxoplasmosis, large gaps still exist in our knowledge concerning the epidemiology and pathophysiology of this potentially blinding infectious disease. Although ocular toxoplasmosis is considered to have a high health burden, still little is known about

  12. Streptozotocin-Induced Diabetes Models: Pathophysiological Mechanisms and Fetal Outcomes

    Directory of Open Access Journals (Sweden)

    D. C. Damasceno

    2014-01-01

    Full Text Available Glucose homeostasis is controlled by endocrine pancreatic cells, and any pancreatic disturbance can result in diabetes. Because 8% to 12% of diabetic pregnant women present with malformed fetuses, there is great interest in understanding the etiology, pathophysiological mechanisms, and treatment of gestational diabetes. Hyperglycemia enhances the production of reactive oxygen species, leading to oxidative stress, which is involved in diabetic teratogenesis. It has also been suggested that maternal diabetes alters embryonic gene expression, which might cause malformations. Due to ethical issues involving human studies that sometimes have invasive aspects and the multiplicity of uncontrolled variables that can alter the uterine environment during clinical studies, it is necessary to use animal models to better understand diabetic pathophysiology. This review aimed to gather information about pathophysiological mechanisms and fetal outcomes in streptozotocin-induced diabetic rats. To understand the pathophysiological mechanisms and factors involved in diabetes, the use of pancreatic regeneration studies is increasing in an attempt to understand the behavior of pancreatic beta cells. In addition, these studies suggest a new preventive concept as a treatment basis for diabetes, introducing therapeutic efforts to minimize or prevent diabetes-induced oxidative stress, DNA damage, and teratogenesis.

  13. Glucocorticoid-induced myopathy: Pathophysiology, diagnosis, and treatment

    Directory of Open Access Journals (Sweden)

    Anu Gupta

    2013-01-01

    Full Text Available Glucocorticoid-induced myopathy is the most common type of drug-induced myopathy. Nearly 60% of patients with Cushing′s syndrome have muscle weakness. Glucocorticoid-induced muscle atrophy affects mainly fast-twitch glycolytic muscle fibers (type IIb fibers. This brief review will discuss the pathophysiology behind glucocorticoid-induced myopathy, along with diagnostic features and treatment.

  14. Insulin resistance : pathophysiology in South Asians & therapeutic strategies

    NARCIS (Netherlands)

    Sleddering, Maria Alexandra

    2014-01-01

    This thesis describes the pathophysiology of insulin resistance in the South Asian population and comprises studies on pharmacological and weight loss interventions in insulin resistant patients. Because of the increasing number of patients with obesity and T2DM, more research is needed to identify

  15. Insulin resistance : pathophysiology in South Asians & therapeutic strategies

    NARCIS (Netherlands)

    Sleddering, Maria Alexandra

    2014-01-01

    This thesis describes the pathophysiology of insulin resistance in the South Asian population and comprises studies on pharmacological and weight loss interventions in insulin resistant patients. Because of the increasing number of patients with obesity and T2DM, more research is needed to identify

  16. Pathophysiology and treatment of edema following femoropopliteal bypass surgery

    NARCIS (Netherlands)

    te Slaa, A.; Dolmans, D. E. J. G. J.; Ho, G. H.; Moll, F. L.; van der Laan, L.

    2012-01-01

    Substantial lower-limb edema affects the majority of patients who undergo peripheral bypass surgery. Edema has impairing effects on the microvascular and the macrovascular circulation, causes discomfort and might delay the rehabilitation process of the patient. However, the pathophysiology of this e

  17. Pathophysiological Mechanisms of Severe Anaemia in Malawian Children

    NARCIS (Netherlands)

    M.B. van Hensbroek; J.C.J. Calis; K.S. Phiri; R. de Vet; F. Munthali; R. Kraaijenhagen; H. van den Berg; B. Faragher; I. Bates; M.E. Molyneux

    2010-01-01

    Background: Severe anaemia is a major cause of morbidity and mortality in African children. The aetiology is multi-factorial, but interventions have often targeted only one or a few causal factors, with limited success. Methods and Findings: We assessed the contribution of different pathophysiologic

  18. Mitochondria and Energetic Depression in Cell Pathophysiology

    Directory of Open Access Journals (Sweden)

    Stephan Zierz

    2009-05-01

    Full Text Available Mitochondrial dysfunction is a hallmark of almost all diseases. Acquired or inherited mutations of the mitochondrial genome DNA may give rise to mitochondrial diseases. Another class of disorders, in which mitochondrial impairments are initiated by extramitochondrial factors, includes neurodegenerative diseases and syndromes resulting from typical pathological processes, such as hypoxia/ischemia, inflammation, intoxications, and carcinogenesis. Both classes of diseases lead to cellular energetic depression (CED, which is characterized by decreased cytosolic phosphorylation potential that suppresses the cell’s ability to do work and control the intracellular Ca2+ homeostasis and its redox state. If progressing, CED leads to cell death, whose type is linked to the functional status of the mitochondria. In the case of limited deterioration, when some amounts of ATP can still be generated due to oxidative phosphorylation (OXPHOS, mitochondria launch the apoptotic cell death program by release of cytochrome c. Following pronounced CED, cytoplasmic ATP levels fall below the thresholds required for processing the ATP-dependent apoptotic cascade and the cell dies from necrosis. Both types of death can be grouped together as a mitochondrial cell death (MCD. However, there exist multiple adaptive reactions aimed at protecting cells against CED. In this context, a metabolic shift characterized by suppression of OXPHOS combined with activation of aerobic glycolysis as the main pathway for ATP synthesis (Warburg effect is of central importance. Whereas this type of adaptation is sufficiently effective to avoid CED and to control the cellular redox state, thereby ensuring the cell survival, it also favors the avoidance of apoptotic cell death. This scenario may underlie uncontrolled cellular proliferation and growth, eventually resulting in carcinogenesis.

  19. Pathophysiological mechanisms linking obesity and esophageal adenocarcinoma

    Institute of Scientific and Technical Information of China (English)

    Leo; Alexandre; Elizabeth; Long; Ian; LP; Beales

    2014-01-01

    In recent decades there has been a dramatic rise in the incidence of esophageal adenocarcinoma(EAC) in the developed world. Over approximately the same period there has also been an increase in the prevalence of obesity. Obesity, especially visceral obesity, is an important independent risk factor for the development of gastro-esophageal reflux disease, Barrett’s esophagus and EAC. Although the simplest explanation is that this mediated by the mechanical effects of abdominal obesity promoting gastro-esophageal reflux, the epidemiological data suggest that the EAC-promoting effects are independent of reflux. Several, not mutually exclusive, mechanisms have been implicated, which may have different effects at various points along the refluxBarrett’s-cancer pathway. These mechanisms include a reduction in the prevalence of Helicobacter pylori infection enhancing gastric acidity and possibly appetite byincreasing gastric ghrelin secretion, induction of both low-grade systemic inflammation by factors secreted by adipose tissue and the metabolic syndrome with insulin-resistance. Obesity is associated with enhanced secretion of leptin and decreased secretion of adiponectin from adipose tissue and both increased leptin and decreased adiponectin have been shown to be independent risk factors for progression to EAC. Leptin and adiponectin have a set of mutually antagonistic actions on Barrett’s cells which appear to influence the progression of malignant behaviour. At present no drugs are of proven benefit to prevent obesity associated EAC. Roux-en-Y reconstruction is the preferred bariatric surgical option for weight loss in patients with reflux. Statins and aspirin may have chemopreventative effects and are indicated for their circulatory benefits.

  20. Cardiocirculatory pathophysiological mechanisms in severe acute pancreatitis

    Institute of Scientific and Technical Information of China (English)

    Mónica; García; José; Julián; Calvo

    2010-01-01

    Acute pancreatitis (AP) is a common and potentially lethal acute inflammatory process. Although the majority of patients have a mild episode of AP, 10%-20% develop a severe acute pancreatitis (SAP) and suffer systemic inflammatory response syndrome (SIRS) and/or pancreatic necrosis. The main aim of this article is to review the set of events, f irst localized in the pancreas, that lead to pancreatic inflammation and to the spread to other organs contributing to multiorganic shock. The early pathogenic mechanisms in SAP are not completely understood but both premature activation of enzymes inside the pancreas, related to an impaired cytosolic Ca2+ homeostasis, as well as release of pancreatic enzymes into the bloodstream are considered important events in the onset of pancreatitis disease. Moreover, afferent f ibers within the pancreas release neurotransmitters in response to tissue damage. The vasodilator effects of these neurotransmitters and the activation of pro-inflammatory substances play a crucial role in amplifying the inflammatory response, which leads to systemic manifestation of AP. Damage extension to other organs leads to SIRS, which is usually associated with cardiocirculatoryphysiology impairment and a hypotensive state. Hypotension is a risk factor for death and is associated with a signif icant hyporesponsiveness to vasoconstrictors. This indicates that stabilization of the patient, once this pathological situation has been established, would be a very diff icult task. Therefore, it seems particularly necessary to understand the pathological mechanisms involved in the f irst phases of AP to avoid damage beyond the pancreas. Moreover, efforts must also be directed to identify those patients who are at risk of developing SAP.

  1. Investigation of new type Cu-Hf-Al bulk glassy alloys

    Science.gov (United States)

    Nagy, E.; Rontó, V.; Sólyom, J.; Roósz, A.

    2009-01-01

    In the last years new type Cu-Hf-Al ternary alloys were developed with high glass forming ability and ductility. The addition of Al to Cu-Hf alloys results in improvements in glass formation, thermal stability and mechanical properties of these alloys. We have investigated new Cu-based bulk amorphous alloys in Cu-Hf-Al ternary system. The alloys with Cu49Hf42Al9, Cu46Hf45Al9, Cu50Hf42.5Al7.5 and Cu50Hf45Al5 compositions were prepared by arc melting. The samples were made by centrifugal casting and were investigated by X-ray diffraction method. Thermodynamic properties were examined by differential scanning calorimetry and the structure of the crystallising phases by scanning electron microscopy. The determination of liquidus temperatures of alloys were measured by differential thermal analysis.

  2. First-principles studies of HF molecule adsorption on intrinsic graphene and Al-doped graphene

    Science.gov (United States)

    Sun, Yuanyuan; Chen, Li; Zhang, Feiwu; Li, Daoyong; Pan, Hongzhe; Ye, Jun

    2010-10-01

    In the search for a high-sensitivity sensor for HF gas, the adsorption of HF molecules on both intrinsic and Al-doped graphene sheets is studied by first-principles calculations. We find that the adsorption mechanisms of HF molecules are different for intrinsic graphene and Al-doped graphene. Al-doped graphene has higher adsorption energy and shorter connecting distance to the HF molecule than intrinsic graphene. The calculated net electron transfers, electronic density difference images and densities of states give evidence that the adsorption of HF molecules on Al-doped graphene is by chemisorption, while there is weak physisorption on intrinsic graphene. Therefore, Al-doped graphene can be expected to have applications as a novel sensor for the detection of HF gas. The HF molecules adsorbed on Al-doped graphene material can be reactivated by applying an external electric field of 0.013 a.u.

  3. Ferroelectric HfO2 for Emerging Ferroelectric Semiconductor Devices

    Science.gov (United States)

    Florent, Karine

    The spontaneous polarization in ferroelectrics (FE) makes them particularly attractive for non-volatile memory and logic applications. Non-volatile FRAM memories using perovskite structure materials, such as Lead Zirconate Titanate (PZT) and Strontium Bismuth Tantalate (SBT) have been studied for many years. However, because of their scaling limit and incompatibility with CMOS beyond 130 nm node, floating gate Flash memory technology has been preferred for manufacturing. The recent discovery of ferroelectricity in doped HfO2 in 2011 has opened the door for new ferroelectric based devices compatible with CMOS technology, such as Ferroelectric Field Effect Transistor (FeFET) and Ferroelectric Tunnel Junctions (FTJ). This work began with developing ferroelectric hysteresis characterization capabilities at RIT. Initially reactively sputtered aluminum doped HfO 2 films were investigated. It was observed that the composition control using co-sputtering was not achievable within the existing capabilities. During the course of this study, collaboration was established with the NaMLab group in Germany to investigate Si doped HfO2 deposited by Atomic Layer Deposition (ALD). Metal Ferroelectric Metal (MFM) devices were fabricated using TiN as the top and bottom electrode with Si:HfO2 thickness ranging from 6.4 nm to 22.9 nm. The devices were electrically tested for P-E, C-V and I-V characteristics. Structural characterizations included TEM, EELS, XRR, XRD and XPS/Auger spectroscopy. Higher remanant polarization (Pr) was observed for films of 9.3 nm and 13.1 nm thickness. Thicker film (22.9 nm) showed smaller Pr. Devices with 6.4 nm thick films exhibit tunneling behavior showing a memristor like I-V characteristics. The tunnel current and ferroelectricity showed decrease with cycling indicating a possible change in either the structure or the domain configurations. Theoretical simulations using the improved FE model were carried out to model the ferroelectric behavior of

  4. Centrifugal stretching of 170Hf in the interacting boson model

    Directory of Open Access Journals (Sweden)

    Werner V.

    2014-03-01

    Full Text Available We present the results of a recent experiment to deduce lifetimes of members of the ground state rotational band of 170Hf, which show the effect of centrifugal stretching in this deformed isotope. Results are compared to the geometrical confined beta-soft(CBS rotor model, as well as to the interacting boson model (IBM. Two methods to correct for effects due to the finite valence space within the IBM are proposed.

  5. Electrochemical characterization of cast Ti-Hf binary alloys.

    Science.gov (United States)

    Cai, Z; Koike, M; Sato, H; Brezner, M; Guo, Q; Komatsu, M; Okuno, O; Okabe, T

    2005-05-01

    This study characterized the electrochemical behavior of Ti-Hf binary alloys in a simulated oral environment. Ti-Hf alloys (10, 20, 25, 30, 35 and 40 mass% Hf) were prepared by arc-melting titanium sponge and hafnium sponge. Specimens of each alloy (n = 4) were prepared using a dental titanium casting system with a MgO-based investment. Specimens were inspected with X-ray radiography to ensure minimal internal porosity. Castings (n = 4) made from pure titanium and commercially pure titanium were used as controls. The ground flat surface (10 mm x 10 mm) on each specimen where approximately 30 microm was removed was used for the characterization. Sixteen-hour open-circuit potential (OCP) measurement, linear polarization and potentiodynamic cathodic polarization were performed sequentially in aerated (air + 10% CO2) MTZ synthetic saliva at 37 degrees C. Potentiodynamic anodic polarization was conducted in the same medium but deaerated (N2 + 10% CO2) 2 h before and during testing. Polarization resistance (R(P)) and Tafel slopes were determined, as were corrosion current density (I(CORR)) and passive current density (I(PASS)). Results were subjected to nonparametric statistical analysis (alpha = 0.05). The OCP stabilized (mean values -229 mV to -470 mV vs. SCE) for all specimens after the 16-h immersion. Similar passivation was observed for all the metals on their anodic polarization diagrams. The Kruskal-Wallis test showed significant differences in OCP among the test groups (p = 0.006). No significant differences were found in R(P), I(CORR) or I(PASS) among all the metals (p>0.3). Results indicate that the electrochemical behavior of the Ti-Hf alloys examined resembles that of pure titanium.

  6. Self-healing structural properties of thermoplastics in HF field

    Directory of Open Access Journals (Sweden)

    N. G. Filippenko

    2014-01-01

    Full Text Available The article concerns one of the possible ways for safe operation of polymer products with initiating a process of their self-healing. This is especially true for products from polymer materials, used in hard-to-reach areas and units of machines and mechanisms. In this regard, the aim of this study was to develop techniques for a self-healing process of the mechanical properties of products from polymer materials.To achieve this goal, the author has solved problems to define a complex method of HF self-healing of polymer material: damage detection in products from polymer materials, determination of signal initiating the recovery process, determining the efficiency of material regeneration. The present study uses proposed and developed by the author methods for the determination of necessary and sufficient indicators of the strength characteristics of products under realmeteorological and climatic conditions of their operation.To determine the practical results of the developed algorithm for self-healing the polymer products in the HF field, a series of experimental studies has been conducted to regenerate the polyamide cage fatigue destruction of the rolling stock axle equipment of Russian Railways JSC.The obtained results of the strength characteristics of the material under investigation prove the self-healing process of polymer materials in HF field.According to research results, the conclusion is drawn that it is required to provide a technological HF self-healing process of products from polymer materials. The created algorithm of regeneration enables a new approach to study the effects of electromagnetic fields on polymer and polymer-based composite materials when solving the practical tasks to improve the quality of repairing parts from thermoplastics.

  7. Hf--Co--B alloys as permanent magnet materials

    Science.gov (United States)

    McGuire, Michael Alan; Rios, Orlando; Ghimire, Nirmal Jeevi

    2017-01-24

    An alloy composition is composed essentially of Hf.sub.2-XZr.sub.XCo.sub.11B.sub.Y, wherein 0B.sub.Y, wherein 0.ltoreq.X<2 and 0

  8. Ionizing wave via high-power HF acceleration

    CERN Document Server

    Mishin, Evgeny

    2010-01-01

    Recent ionospheric modification experiments with the 3.6 MW transmitter at the High Frequency Active Auroral Research Program (HAARP) facility in Alaska led to discovery of artificial ionization descending from the nominal interaction altitude in the background F-region ionosphere by ~60 km. This paper presents a physical model of an ionizing wavefront created by suprathermal electrons accelerated by the HF-excited plasma turbulence.

  9. Study on Preparation of 182Hf AMS Standards

    Institute of Scientific and Technical Information of China (English)

    YINXin-yi; JIANGShan; HEMing; ZHANGChun-hua; ZHANGSheng-dong

    2003-01-01

    The neutron-rich isotope 182Hf with its half-life of (9±2)×106 a produced by neutron activation can be used to determine the neutron flux of some places, in order to study the transport of radioactive nuclides and the safe disposal of nuclear waste. AMS is a kind of relative measurement method with high sensitivity (10-15), it requires corresponding standard samples.

  10. Ionizing wave via high-power HF acceleration

    OpenAIRE

    Mishin, Evgeny; Pedersen, Todd

    2010-01-01

    Recent ionospheric modification experiments with the 3.6 MW transmitter at the High Frequency Active Auroral Research Program (HAARP) facility in Alaska led to discovery of artificial ionization descending from the nominal interaction altitude in the background F-region ionosphere by ~60 km. This paper presents a physical model of an ionizing wavefront created by suprathermal electrons accelerated by the HF-excited plasma turbulence.

  11. On the Onset of HF-Induced Airglow at HAARP

    Science.gov (United States)

    2007-11-02

    AFRL-VS-HA-TR-2005-1061 JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109, A02305, doi:10.1029/2003JA010205, 2004 On the onset of HF-induced airglow at HAARP ...line) during the February 2002 campaign at the High Frequency Active Auroral Research Program ( HAARP ) heating facility are analyzed. We find that... HAARP , J. Geophys. Res., 109, A02305, doi: 10.1029/2003JA010205. 1. Introduction known as the parametric decay (PDI) or oscillating two- [2] A

  12. HF Over-the-Horizon Radar System Performance Analysis

    Science.gov (United States)

    2007-09-01

    target detection technique and radar equations are applied. Chapter V uses PROPLAB model simulation to bring in the principle of raytracing and... RADAR SYSTEM PERFORMANCE ANALYSIS by Bin-Yi Liu September 2007 Thesis Co-Advisors: Phillip E. Pace Jeffrey B. Knorr THIS PAGE...Thesis 4. TITLE AND SUBTITLE HF Over-the-Horizon Radar System Performance Analysis 6. AUTHOR(S) Bin-Yi Liu 5. FUNDING NUMBERS 7. PERFORMING

  13. Wideband high frequency (HF) skywave channel parameters from narrowband measurements

    Science.gov (United States)

    Hausman, Cynthia L.; Uffelman, Donald R.; Walton, Thomas L.

    The HF wideband channel allow the use of spread-spectrum techniques to provide covert communications with low probability of intercept (LPI) and antijam protection. The objective of this work is to determine the extent to which oblique narrowband channel measurements can be used to infer effects in the wideband skywave channel. If oblique narrowband channel measurements can be used as a basis for developing wideband channel models, a large number of existing narrowband measurements can be made available for this task.

  14. TaN interface properties and electric field cycling effects on ferroelectric Si-doped HfO2 thin films

    Science.gov (United States)

    Lomenzo, Patrick D.; Takmeel, Qanit; Zhou, Chuanzhen; Fancher, Chris M.; Lambers, Eric; Rudawski, Nicholas G.; Jones, Jacob L.; Moghaddam, Saeed; Nishida, Toshikazu

    2015-04-01

    Ferroelectric HfO2-based thin films, which can exhibit ferroelectric properties down to sub-10 nm thicknesses, are a promising candidate for emerging high density memory technologies. As the ferroelectric thickness continues to shrink, the electrode-ferroelectric interface properties play an increasingly important role. We investigate the TaN interface properties on 10 nm thick Si-doped HfO2 thin films fabricated in a TaN metal-ferroelectric-metal stack which exhibit highly asymmetric ferroelectric characteristics. To understand the asymmetric behavior of the ferroelectric characteristics of the Si-doped HfO2 thin films, the chemical interface properties of sputtered TaN bottom and top electrodes are probed with x-ray photoelectron spectroscopy. Ta-O bonds at the bottom electrode interface and a significant presence of Hf-N bonds at both electrode interfaces are identified. It is shown that the chemical heterogeneity of the bottom and top electrode interfaces gives rise to an internal electric field, which causes the as-grown ferroelectric domains to preferentially polarize to screen positively charged oxygen vacancies aggregated at the oxidized bottom electrode interface. Electric field cycling is shown to reduce the internal electric field with a concomitant increase in remanent polarization and decrease in relative permittivity. Through an analysis of pulsed transient switching currents, back-switching is observed in Si-doped HfO2 thin films with pinched hysteresis loops and is shown to be influenced by the internal electric field.

  15. Detection of HCl and HF by TTFMS and WMS.

    Science.gov (United States)

    De Luca, Anna Chiara; Pesce, Giuseppe; Rusciano, Giulia; Sasso, Antonio

    2006-04-01

    In this work we discuss on a compact spectrometer based on DFB diode lasers for detection of chloridric and fluoridric acids. HCl and HF concentrations are determined through optical absorption of the P(4) line (lambda=1.7 microm) and the R(3) line (lambda=1.3 microm), respectively. Both lines belong to first overtone vibrational bands and their line strengths are 7.8 x 10(-21)cm/molecule for HCl and 2.8 x 10(-20)cm/molecule for HF. We chose these lines for their relative high intensities and because they are quite far from water vapour lines which represent the main interfering gas for trace-gases analysis. To detect these species we used two different high frequency modulation techniques: two-tone frequency modulation spectroscopy (f(1)=800 MHz and f(2)=804 MHz) was used for HCl while for HF we followed a simpler approach based on wavelength modulation spectroscopy (f=600 kHz). We demonstrate that the two techniques provide comparable detection limit of about 80 ppbV at atmospheric pressure. Positive testing of our spectrometer makes it suitable for in situ measurements of exhaust gases coming from waste incinerators.

  16. Multiple excitation modes in 163Hf

    DEFF Research Database (Denmark)

    Yadav, Rachita; Ma, J.C.; Marsh, J.C.

    2014-01-01

    Excited states of Hf163 were populated using the Zr94(Ge74,5n) reaction and the decay γ rays were measured with the Gammasphere spectrometer. Two previously known bands were extended to higher spins, and nine new bands were identified. In addition to bands associated with three- and five-quasipar......Excited states of Hf163 were populated using the Zr94(Ge74,5n) reaction and the decay γ rays were measured with the Gammasphere spectrometer. Two previously known bands were extended to higher spins, and nine new bands were identified. In addition to bands associated with three- and five......-quasiparticle configurations, two γ−vibrational bands coupled to the i13/2 excitation were also observed. The lowest level of a newly identified, negative-parity band is proposed to be the ground state of the nucleus. A systematic delay of the high-spin proton crossing frequency with increasing quadrupole deformation from Hf...

  17. Electronic structures and properties of Ti, Zr and Hf metals

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The electronic structures of pure Ti, Zr and Hf metals with hcp structure were determined by one-atom (OA) theory. According to the electronic structures of these metals,their potential curves, cohesive energies, lattice constants, elasticities and the temperature dependence of linear thermal expansion coefficients were calculated. The electronic structures and characteristic properties of these metals with bcc and fcc structures and liquids were also studied. The results show that the electronic structures of Ti, Zr and Hf metals are respectively [Ar](3dn)0.481 0(3dc)2.085 7(4sc)1.000 0(4sf)0.433 3, [Kr](4dn)0.396 8(4dc)2.142 8(5sc)1.262 0(5sf)0.198 4, [Xe](5dn)0.368 0(5dc)2.041 4(6sc)1.406 6(6sf)0.184 0. It is explained why the pure Ti, Zr and Hf metals with hcp and bcc structures can exist naturally, while those with fcc structure can not.

  18. Lu-Hf and Sm-Nd garnet geochronology

    DEFF Research Database (Denmark)

    Smit, Matthijs Arjen; Scherer, Erik E.; Mezger, Klaus

    2013-01-01

    are similar among grains having radii larger than 1.3 mm (weighted mean: 2714±6 Ma2714±6 Ma; 2 s.d.) and up to 20 Myr younger for finer fractions. In contrast, Sm–Nd dates are equal to or younger than the 2641–2637 Ma age of peak metamorphism. The roles of concurrently digested inclusions and core–rim Lu......To investigate the systematics of the 176Lu–176Hf and 147Sm–143Nd garnet chronometers, we performed REE and isotope analyses on garnet crystals of different size (0.55–3.1 mm radius) from a single granulite specimen (Archean Pikwitonei Granulite Domain, Manitoba, Canada). The Lu–Hf dates....../Sm fractionation are quantitatively evaluated and excluded as causes for the observed age heterogeneity. Instead, the isotope dates are interpreted to reflect partial loss of radiogenic 176Hf and 143Nd, and are used to constrain the systematics of the garnet chronometers at high temperature. The data constrain...

  19. TID measurement using oblique transmissions of HF pulses

    Science.gov (United States)

    Galkin, Ivan; Reinisch, Bodo; Huang, Xueqin; Paznukhov, Vadym; Hamel, Ryan; Kozlov, Alexander; Belehaki, Anna

    2017-04-01

    The Traveling Ionospheric Disturbance (TID), a wave-like signature of moving plasma density modulation in the ionosphere, is widely acknowledged for its utility in backtracking the anomalous events responsible for the TID generation, and as a major inconvenience to high-frequency (HF) operational systems because of its deleterious impact on the accuracy of navigation and geolocation. The pilot project "Net-TIDE" for the real-time detection and evaluation of TIDs began its operation in 2016 based on the remote-sensing data from synchronized, network-coordinated HF sounding between pairs of DPS4D ionosondes at five participating observatories in Europe. Measurement of all signal properties (Doppler frequency, angle of arrival, and time-of-flight from transmitter to receiver) proved to be instrumental in detecting the TID and deducing the TID parameters: amplitude, wavelength, phase velocity, and direction of propagation. Processing of the measured HF signal data required a specialized signal processing technique that is capable of consistently extracting different signals that have propagated along different ionospheric paths. The multi-path signal environment proved to be the greatest challenge for the reliable TID specification by Net-TIDE, demanding the development of an intelligent system for "signal tracking". The intelligent system is based on a neural network model of a pre-attentive vision capable of extracting continuous signal tracks from the multi-path signal ensemble. Specific examples of the Net-TIDE algorithm suite operation and its suitability for a fully automated TID warning service are discussed.

  20. High-spin positive-parity states in 179Hf studied by the 180Hf(τ, α) 179Hf reaction AT 32 MeV

    Science.gov (United States)

    Thorsteinsen, T. F.; Løvhøiden, G.; Vaagen, J. S.; Bjørnberg, A.; Burke, D. G.

    1981-06-01

    Full angular distributions are presented for states populated in the reaction 180Hf(τ, α) 179Hf at 32 MeV beam energy. Positive-parity states associated with the i {13}/{2} unique parity intruder orbital are given special attention. Thus, angular distributions for the five first members of the [624 {9}/{2}] groundstate sequence are given, as well as for a number of more highly excited states, some being new assignments. The distribution of l = 6 transfer strength is quite characteristic, two {13}/{2}+ states being substantially more populated than the rest. The characteristic features of the data are explained by a quasiparticle-rotor calculation employing deformed Woods-Saxon orbitals, but only if the hexadecapole shape parameter of the nuclear potential is β 4 ˜ -0.08. The often anomalous differential cross sections for I π ≠ {13}/{2}+ band members are well accounted for by a rotor model CCBA calculation employing transfer form factors extracted from the orbitals of the deformed Woods-Saxon field, and including non-adiabatic Coriolis mixing effects.

  1. Hf isotopic compositions of the standard zircons for U-Pb dating

    Institute of Scientific and Technical Information of China (English)

    XU Ping; WU Fuyuan; XIE Liewen; YANG Yueheng

    2004-01-01

    Using the newly published Yb isotopic abundances and the mass bias relationship between Yb and Hf, we carried out an analysis of Hf isotopes in the standard zircon 91500 by means of 193 nm laser attached to Neptune multi-collector ICP-MS (LA-MC-ICPMS). The obtained Hf isotopic data, in either in situ or line scan modes, are not only identical for different spot sizes, but also are consistent with previously published results obtained on TIMS or other MC-ICPMS machines within errors. This indicates that it is possible to obtain reliable 176Hf/177Hf isotopic ratios for zircon in either in situ or line scan conditions on LA-MC-ICPMS machine, and the applied procedures in our study for elemental interfering correction are appropriate for the purpose of acquiring satisfactory accuracy for Hf isotope analyses. The Hf isotopic compositions of four zircon standards in high spatial resolution U-Pb dating, 91500, CZ3,CN92-1 and TEMORA, are measured, respectively. The obtained 176Hf/177Hf ratios are 0.282316+4 (n = 34, 2σ) for 91500, 0.281704±6 (n = 16, 2σ) for CZ3, 0.282200±6 (n = 20,2σ-) for CN92-1 and 0.282684±14 (n = 24, 2σ) for TEMORA,respectively, with 176Lu/177Hf ratios of ~0.00031, 0.000036,0.00083 and 0.00127. Zircons 91500 and CZ3 show narrower variations in 176Hf/177Hf and 176Lu/177Hf ratios than those of zircons CN92-1 and TEMORA, and thus are appropriate standards for the Hf isotope analysis.

  2. Electrical characteristics of MOS capacitor with HfTiON gate dielectric and HfTiSiON interlayer

    Institute of Scientific and Technical Information of China (English)

    Chen Wei-Bing; Xu Jing-Ping; Lai Pui-To; Li Yan-Ping; Xu Sheng-Guo; Chan Chu-Lok

    2006-01-01

    The paper reports that HfTiO dielectric is deposited by reactive co-sputtering of Hf and Ti targets in an Ar/O2 ambience, followed by an annealing in different gas ambiences of N2, NO and NHa at 600°C for 2 min. Capacitance-voltage and gate-leakage properties are characterized and compared. The results indicate that the NO-annealed sample exhibits the lowest interface-state and dielectric-charge densities and best device reliability. This is attributed to the fact that nitridation can create strong Si≡N bonds to passivate dangling Si bonds and replace strained Si- O bonds, thus the sample forms a hardened dielectric/Si interface with high reliability.

  3. Effect of atomic size on undercoolability of binary solid solution alloy liquids with Zr, Ti, and Hf using electrostatic levitation.

    Science.gov (United States)

    Jeon, S; Kang, D-H; Lee, Y H; Lee, S; Lee, G W

    2016-11-07

    We investigate the relationship between the excess volume and undercoolability of Zr-Ti and Zr-Hf alloy liquids by using electrostatic levitation. Unlike in the case of Zr-Hf alloy liquids in which sizes of the constituent atoms are matched, a remarkable increase of undercoolability and negative excess volumes are observed in Zr-Ti alloy liquids as a function of their compositional ratios. In this work, size mismatch entropies for the liquids were obtained by calculating their hard sphere diameters, number densities, and packing fractions. We also show that the size mismatch entropy, which arises from the differences in atomic sizes of the constituent elements, plays an important role in determining the stabilities of metallic liquids.

  4. Potential Role of Dipeptidyl Peptidase IV in the Pathophysiology of Heart Failure

    Directory of Open Access Journals (Sweden)

    Thiago A. Salles

    2015-02-01

    Full Text Available Dipeptidyl peptidase IV (DPPIV is a widely expressed multifunctional serine peptidase that exists as a membrane-anchored cell surface protein or in a soluble form in the plasma and other body fluids. Numerous substrates are cleaved at the penultimate amino acid by DPPIV, including glucagon-like peptide-1 (GLP-1, brain natriuretic peptide (BNP and stromal cell-derived factor-1 (SDF-α, all of which play important roles in the cardiovascular system. In this regard, recent reports have documented that circulating DPPIV activity correlates with poorer cardiovascular outcomes in human and experimental heart failure (HF. Moreover, emerging evidence indicates that DPPIV inhibitors exert cardioprotective and renoprotective actions in a variety of experimental models of cardiac dysfunction. On the other hand, conflicting results have been found when translating these promising findings from preclinical animal models to clinical therapy. In this review, we discuss how DPPIV might be involved in the cardio-renal axis in HF. In addition, the potential role for DPPIV inhibitors in ameliorating heart disease is revised, focusing on the effects of the main DPPIV substrates on cardiac remodeling and renal handling of salt and water.

  5. Potential Role of Dipeptidyl Peptidase IV in the Pathophysiology of Heart Failure

    Science.gov (United States)

    Salles, Thiago A.; dos Santos, Leonardo; Barauna, Valério G.; Girardi, Adriana C. C.

    2015-01-01

    Dipeptidyl peptidase IV (DPPIV) is a widely expressed multifunctional serine peptidase that exists as a membrane-anchored cell surface protein or in a soluble form in the plasma and other body fluids. Numerous substrates are cleaved at the penultimate amino acid by DPPIV, including glucagon-like peptide-1 (GLP-1), brain natriuretic peptide (BNP) and stromal cell-derived factor-1 (SDF-α), all of which play important roles in the cardiovascular system. In this regard, recent reports have documented that circulating DPPIV activity correlates with poorer cardiovascular outcomes in human and experimental heart failure (HF). Moreover, emerging evidence indicates that DPPIV inhibitors exert cardioprotective and renoprotective actions in a variety of experimental models of cardiac dysfunction. On the other hand, conflicting results have been found when translating these promising findings from preclinical animal models to clinical therapy. In this review, we discuss how DPPIV might be involved in the cardio-renal axis in HF. In addition, the potential role for DPPIV inhibitors in ameliorating heart disease is revised, focusing on the effects of the main DPPIV substrates on cardiac remodeling and renal handling of salt and water. PMID:25690036

  6. Impact of famous CEDAR, GEM and ISTP geomagnetic Storms on HF Radio Propagation

    Science.gov (United States)

    Blagoveshchensky, D.; Sergeeva, M.

    The mighty geomagnetic storms due to the extraordinary Sun s activity cause as a rule some impacts in these areas radiation effects on human and satellites commercial airlines outages electric power and other geomagnetic effects navigation and communication GPS effects ionospheric disturbances HF communication effects Therefore our scientific understanding of this activity is very important Joint efforts for example within the framework of the CAWSES enable progress in our ability to i identify critical inputs to specify the geospace environment at a level needed to minimize impacts on technology human society and life and ii support the development of robust models that predict conditions in geospace based on understanding of the Sun-Earth system and all of its interacting components In this study influence of 14 geomagnetic storms from a list of CEDAR GEM and ISTP storms within 1997-99 on radio propagation conditions have been investigated These conditions were estimated through variations of the MOF and LOF the maximum and lowest operation frequencies on each path from three high-latitude HF radio paths of North-west Russia before during and after a storm It was shown that the storm impact on the ionosphere and radio propagation for each storm has an individual character Nevertheless the common character of the certain manifestations during storm-time was revealed For example the frequency range MOF - LOF is getting wider several hours before a storm then it is sharply narrow during a storm-time and further it is expanded again several

  7. Towards the creation of a multi-institutional HF Radar Network in the Gulf of Mexico.

    Science.gov (United States)

    Flores-vidal, X.; Flament, P. J.; Durazo, R.; Navarro, L. F.; Salles, P.; Alvarez, P.; Carrillo, L.; Kurczyn, J. A.; Ulloa, M. J.; Rodriguez, I.; Toro Valencia, V. G.; Marin, M.; Perales, H.; Sanay, R.

    2016-12-01

    The Gulf of Mexico is source of important resources for both Mexico and USA, its beaches and coasts bring economical resources for these countries through the generation of jobs on the fisheries, touristic and industrial sectors. However, systematic monitoring is still necessary to evaluate its health and dynamics. This work is part of a multi-institutional project named "Implementation of oceanographic observational networks (physical, geochemical and ecological) to generate scenarios for possible contingencies related to the exploration and production of hydrocarbons in the deep waters of the Gulf of Mexico" (funded by SENER-CONACyT) which is an unprecedented Mexican joint effort to better understand the dynamics in the Gulf of Mexico. We will present the first actions towards the creation of the Mexican multi-Institutional HF Radar Network, which will allow us to synoptically map in real time the sea surface currents up to 200 km offshore. We expect to attract collaborations with the active or ongoing USA HF radar stations and institutions along the Gulf of Mexico, as well as to share methodologies and to evaluate standard data formats. The Radar Network in the Gulf of Mexico is planned to be active during 2017-2018, and it is expected to be permanent.

  8. High-spin states and lifetime measurements in sup 1 sup 7 sup 1 Hf

    CERN Document Server

    Cullen, D M; Appelbe, D E; Wilson, A N; Paul, E S; Bergström, M H; Sharpey-Schafer, J F; Baktash, C; Frosch, I; Lee, I Y; Macchiavelli, A O; MacLeod, R W; Prevost, D; Theisen, C; Curien, D

    2000-01-01

    This paper describes the results of two complementary experiments which studied the properties of the well-deformed nucleus sup 1 sup 7 sup 1 Hf. The first experiment, with a thin self-supporting target, extended the rotational bands built upon the [633]7/2, [512]5/2 and [521]1/2 configurations up to spins of 73/2-85/2 Planck constant. The configurations of these bands and observed band crossings are discussed within the framework of the cranked-shell model. The second experiment employed a backed target in order to measure the lifetimes, by the Doppler Shift Attenuation method, and thereby establish deformations for some of the states in the collective rotational bands. The extracted deformations are found to be consistent with those predicted from theoretical Total Routhian Surface calculations. These deformations provide strong evidence that the high-spin states in sup 1 sup 7 sup 1 Hf, and perhaps more importantly, in the region where the high-K (K suppi=19/2 sup + and K suppi=23/2 sup -) isomeric states ...

  9. The magnetic properties of $^{\\rm 177}$Hf and $^{\\rm 180}$Hf in the strong coupling deformed model

    CERN Document Server

    Muto, S; Bingham, C R; Stone, J R; Walker, P M; Audi, G; Gaulard, C; Köster, U; Nikolov, J; Nishimura, K; Ohtsubo, T; Podolyak, Z; Risegari, L; Simpson, G S; Veskovic, M; Walters, W B

    2014-01-01

    This paper reports NMR measurements of the magnetic dipole moments of two high-K isomers, the 37/2$^-$, 51.4 m, 2740 keV state in $^{\\rm 177}$Hf and the 8$^-$, 5.5 h, 1142 keV state in $^{\\rm 180}$Hf by the method of on-line nuclear orientation. Also included are results on the angular distributions of gamma transitions in the decay of the $^{\\rm 177}$Hf isotope. These yield high precision E2/M1 multipole mixing ratios for transitions in bands built on the 23/2$^+$, 1.1 s, isomer at 1315 keV and on the 9/2$^+$, 0.663 ns, isomer at 321 keV. The new results are discussed in the light of the recently reported finding of systematic dependence of the behavior of the g$_{\\rm R}$ parameter upon the quasi-proton and quasi-neutron make up of high-K isomeric states in this region.

  10. The prognostic importance of lung function in patients admitted with heart failure

    DEFF Research Database (Denmark)

    Iversen, Kasper Karmark; Kjaergaard, Jesper; Akkan, Dilek

    2010-01-01

    The purpose of the present study was to determine the prognostic importance for all-cause mortality of lung function variables obtained by spirometry in an unselected group of patients admitted with heart failure (HF).......The purpose of the present study was to determine the prognostic importance for all-cause mortality of lung function variables obtained by spirometry in an unselected group of patients admitted with heart failure (HF)....

  11. Pathology, pathophysiology, and treatment strategies of endocrine disorders and their cardiac complications.

    Science.gov (United States)

    Luk, Adriana; Ezzat, Shereen; Butany, Jagdish

    2013-08-01

    The cardiovascular system is affected by a multitude of endocrine disorders, including dysfunction of the thyroid, calcium, glucocorticoids, insulin/glucose, and growth hormone axes. Since most of these changes in the cardiovascular system are reversible when treated, early diagnosis is important, as if left untreated, they may become fatal. This review focuses on the pathophysiology, clinical presentation, pathology, and treatment of patients with these endocrine diseases who present with a variety of cardiovascular manifestations. Neuroendocrine tumors presenting with the carcinoid syndrome and their cardiovascular manifestations are also discussed. © 2013 Elsevier Inc. All rights reserved.

  12. Tipping the balance: the pathophysiology of obesity and type 2 diabetes mellitus.

    Science.gov (United States)

    McKenney, Rachel L; Short, Daniel K

    2011-12-01

    Obesity plays a major role in the development of type 2 diabetes mellitus, and it has long been accepted that weight loss plays a significant role in diabetes therapy. This weight loss has traditionally been accomplished through lifestyle changes including diet and exercise. What has only more recently gained acceptance is that bariatric surgery may have a role to play in diabetes therapy as well. This article discusses the pathophysiology of type 2 diabetes mellitus and obesity and provides a basic understanding of these diseases, which forms the basis for understanding the importance of weight loss in their treatment. Copyright © 2011. Published by Elsevier Inc.

  13. Dumping Syndrome: A Review of the Current Concepts of Pathophysiology, Diagnosis, and Treatment.

    Science.gov (United States)

    Berg, Patrick; McCallum, Richard

    2016-01-01

    Gastric surgery has long been known to be a cause of dumping syndrome (DS). However, the increasing incidence of gastric bypass surgery, as well as reports of DS unrelated to previous gastric surgeries, has increased the importance of understanding DS in recent years. DS is due to the gastrointestinal response to voluminous and hyperosmolar chyme that is rapidly expelled from the stomach into the small intestine. This response involves neural and hormonal mechanisms. This review encompasses the symptoms, diagnosis, and treatment approaches of DS and also focuses on the current research status of the pathophysiology of DS.

  14. Carbon dioxide production during cardiopulmonary bypass: pathophysiology, measure and clinical relevance.

    Science.gov (United States)

    Ranucci, Marco; Carboni, Giovanni; Cotza, Mauro; de Somer, Filip

    2017-01-01

    Carbon dioxide production during cardiopulmonary bypass derives from both the aerobic metabolism and the buffering of lactic acid produced by tissues under anaerobic conditions. Therefore, carbon dioxide removal monitoring is an important measure of the adequacy of perfusion and oxygen delivery. However, routine monitoring of carbon dioxide removal is not widely applied. The present article reviews the main physiological and pathophysiological sources of carbon dioxide, the available techniques to assess carbon dioxide production and removal and the clinically relevant applications of carbon dioxide-related variables as markers of the adequacy of perfusion during cardiopulmonary bypass.

  15. Mechanisms in endocrinology. Role of emotional stress in the pathophysiology of Graves' disease.

    Science.gov (United States)

    Falgarone, Géraldine; Heshmati, Hassan M; Cohen, Régis; Reach, Gérard

    2013-01-01

    The role of stress in the pathophysiology of Graves' disease is suggested by several clinical observations, by recent advances in immunology and by better understanding of autoimmune diseases which provides new insights into potential effects of stress hormones on T helper cell imbalance involved in the pathogenesis of autoimmune diseases. Stress management should therefore be an important part of the treatment of Graves' disease, as stress reduction may improve the effect of therapy. However, this field still requires interventional data to support stress management in the treatment of Graves' disease.

  16. Water mass circulation and weathering inputs in the Labrador Sea based on coupled Hf-Nd isotope compositions and rare earth element distributions

    Science.gov (United States)

    Filippova, Alexandra; Frank, Martin; Kienast, Markus; Rickli, Jörg; Hathorne, Ed; Yashayaev, Igor M.; Pahnke, Katharina

    2017-02-01

    The Labrador Sea is one of the key areas for deep water formation driving the Atlantic thermohaline circulation and thus plays an important role in Northern Hemisphere climatic fluctuations. In order to better constrain the overturning processes and the origins of the distinct water masses, combined dissolved Hf-Nd isotopic compositions and rare earth element (REE) distribution patterns were obtained from four water depth profiles along a section across the Labrador Sea. These were complemented by one surface sample off the southern tip of Greenland, three shallow water samples off the coast of Newfoundland, and two deep water samples off Nova Scotia. Although light REEs are markedly enriched in the surface waters off the coast of Newfoundland compared to north Atlantic waters, the REE concentration profiles are essentially invariant throughout the water column across the Labrador Sea. The hafnium concentrations of surface waters exhibit a narrow range between 0.6 and 1 pmol/kg but are not significantly higher than at depth. Neodymium isotope signatures (ɛNd) vary from unradiogenic values between -16.8 and -14.9 at the surface to more radiogenic values near -11.0 at the bottom of the Labrador Sea mainly reflecting the advection of the Denmark Strait Overflow Water and North East Atlantic Deep Water, the signatures of which are influenced by weathering contributions from Icelandic basalts. Unlike Nd, water column radiogenic Hf isotope signatures (ɛHf) are more variable representing diverse weathering inputs from the surrounding landmasses. The least radiogenic seawater ɛHf signatures (up to -11.7) are found in surface waters close to Greenland and near the Canadian margin. This reflects the influence of recirculating Irminger Current Waters, which are affected by highly unradiogenic inputs from Greenland. A three to four ɛHf unit difference is observed between Denmark Strait Overflow Water (ɛHf ∼ -4) and North East Atlantic Deep Water (ɛHf ∼ -0

  17. Lu-Hf and Sm-Nd geochronology of garnet gneisses in the central Appalachians, U.S.: Implications for the timing and duration of Grenville Orogeny

    Science.gov (United States)

    Vervoort, Jeff; Ramsey, Molly; Mulcahy, Sean; Aleinikoff, John; Southworth, Scott

    2014-05-01

    The Grenville orogeny is one of the most significant geological events in Earth's history with remnants of this event prominent on virtually every continent. Constraining its timing and duration is important not only for understanding the tectonics of the Grenville itself, but also for understanding supercontinent cycles and other questions of Earth's evolution. In order to provide better constraints on the timing of Grenvillian metamorphism, we analyzed garnet-bearing Mesoproterozoic ortho and paragneisses, collected along a 150 km transect in the northern Blue Ridge Province, using combined Lu-Hf and Sm-Nd geochronology. The orthogneisses have U-Pb zircon crystallization ages of ~1140 and 1100 Ma. The paragneisses have maximum depositional ages ~1050 to 1020 Ma, based on the youngest detrital zircon populations. Zircon overgrowths and monazite ages suggest metamorphic events between ~1050 and 960 Ma. The Lu-Hf and Sm-Nd data for these samples both yield robust garnet ages with large spread of parent/daughter ratios, low age uncertainties, and low MSWD values. Lu-Hf ages define a narrow time span (1043±12 Ma to 1016±4 Ma; wtd. mean, 1024±7 Ma, 2σ). The Sm-Nd ages, determined on the same solutions as Lu-Hf, also define a narrow time range but are systematically younger (974±11 Ma to 932±5 Ma; wtd. mean, 957±10 Ma). The average difference between Lu-Hf and Sm-Nd ages is 67 Ma; the oldest Sm-Nd age is 40 Ma younger than the youngest Lu-Hf age. These large systematic differences in the ages are enigmatic. While Sm-Nd ages younger than Lu-Hf are not uncommon, these differences are typically small. There are, however, potential explanations for these differences. (1) Lu partitions strongly into garnet during growth resulting in high Lu/Hf ratios in the core and yielding ages weighted toward the beginning of growth (e.g., Skora, 2006); no similar partitioning exists in Sm/Nd and these ages reflect mean garnet growth. (2) Lu diffuses much faster than Hf at elevated

  18. Wave parameters comparisons between High Frequency (HF) radar system and an in situ buoy: a case study

    Science.gov (United States)

    Fernandes, Maria; Alonso-Martirena, Andrés; Agostinho, Pedro; Sanchez, Jorge; Ferrer, Macu; Fernandes, Carlos

    2015-04-01

    The coastal zone is an important area for the development of maritime countries, either in terms of recreation, energy exploitation, weather forecasting or national security. Field measurements are in the basis of understanding how coastal and oceanic processes occur. Most processes occur over long timescales and over large spatial ranges, like the variation of mean sea level. These processes also involve a variety of factors such as waves, winds, tides, storm surges, currents, etc., that cause huge interference on such phenomena. Measurement of waves have been carried out using different techniques. The instruments used to measure wave parameters can be very different, i.e. buoys, ship base equipment like sonar and satellites. Each equipment has its own advantage and disadvantage depending on the study subject. The purpose of this study is to evaluate the behaviour of a different technology available and presently adopted in wave measurement. In the past few years the measurement of waves using High Frequency (HF) Radars has had several developments. Such a method is already established as a powerful tool for measuring the pattern of surface current, but its use in wave measurements, especially in the dual arrangement is recent. Measurement of the backscatter of HF radar wave provides the raw dataset which is analyzed to give directional data of surface elevation at each range cell. Buoys and radars have advantages, disadvantages and its accuracy is discussed in this presentation. A major advantage with HF radar systems is that they are unaffected by weather, clouds or changing ocean conditions. The HF radar system is a very useful tool for the measurement of waves over a wide area with real-time observation, but it still lacks a method to check its accuracy. The primary goal of this study was to show how the HF radar system responds to high energetic variations when compared to wave buoy data. The bulk wave parameters used (significant wave height, period and

  19. Epidemiology, pathophysiology, and the future of ocular toxoplasmosis.

    Science.gov (United States)

    Kijlstra, Aize; Petersen, Eskild

    2014-04-01

    Despite large advances in the field of ocular toxoplasmosis, large gaps still exist in our knowledge concerning the epidemiology and pathophysiology of this potentially blinding infectious disease. Although ocular toxoplasmosis is considered to have a high health burden, still little is known about its exact prevalence and how it affects the quality of life. The epidemiology of toxoplasmosis depends on local habits throughout the globe, and changes are likely in view of increased meat consumption in developing countries and demands for higher animal welfare in the Western world. Water is increasingly seen as an important risk factor and more studies are needed to quantitate and control the role of water exposure (drinking, swimming). Tools are now becoming available to study both the human host as well as parasite genetic factors in the development of ocular toxoplasmosis. Further research on the role of Toxoplasma strains as well as basic studies on parasite virulence is needed to explain why Toxoplasma associated eye disease is so severe in some countries, such as Brazil. Although genetic analysis of the parasite represents the gold standard, further developments in serotyping using peptide arrays may offer practical solutions to study the role of parasite strains in the pathogenesis of Toxoplasma retinochoroiditis. More research is needed concerning the pathways whereby the parasite can infect the retina. Once in the retina further tissue damage may be due to parasite virulence factors or could be caused by an aberrant host immune response. Local intraocular immune responses are nowadays used for diagnostic procedures. Future developments may include the use of Raman technology or the direct visualization of a Toxoplasma cyst by optical coherence tomography (OCT). With the availability of ocular fluid specimens obtained for diagnostic purposes and the development of advanced proteomic techniques, a biomarker fingerprint that is unique for an eye with

  20. Rhegmatogenous retinal detachment: a reappraisal of its pathophysiology and treatment.

    Science.gov (United States)

    Kuhn, Ferenc; Aylward, Bill

    2014-01-01

    This article represents a synthesis of an extensive literature review and the authors' decades-long personal experience with both scleral buckling (SB) and vitrectomy for rhegmatogenous retinal detachment (RD). Presenting a coherent understanding of the pathophysiology and treatment of RD, the authors confirm numerous findings described in earlier publications but also challenge certain long-standing dogmas. The key argument made here is that it is extremely rare for the chain of events leading to an RD to start with a retinal pathology. Rather, the initial pathology is syneresis of the vitreous, which then allows gel movement (intraocular currents). At the point of vitreoretinal adhesion, dynamic traction is exerted on the retina, which may be sufficient to tear it. If the tear is operculated and the dynamic traction overcomes the forces keeping the neuroretina and retinal pigment epithelium (RPE) together, the heretofore virtual subretinal space becomes accessible through the retinal tear. The intraocular currents allow the free (nonbound) intravitreal fluid to enter the subretinal space, and once the amount of the incoming fluid overwhelms the draining capacity of the RPE, an RD ensues. Detachment of the posterior cortical vitreous (PVD) is not a necessary prerequisite to RD development; furthermore, PVD cannot be diagnosed preoperatively with adequate certainty with current technology such as biomicroscopy, ultrasonography or optical coherence tomography. The surgeon should expect no or only partial (anomalous) PVD at the time of surgical repair in over half of eyes. The treatment's primary goal must thus be weakening (pneumatic retinopexy, SB) or eliminating (vitrectomy) this dynamic traction. If vitrectomy is employed, it must be a truly complete vitreous removal. This includes a surgically induced PVD if one is not present, close shaving at the periphery, and removing the vitreous immediately behind the lens. The vitrectomy is followed by the creation of a

  1. Adrenomedullin in the kidney-renal physiological and pathophysiological roles.

    Science.gov (United States)

    Nishikimi, Toshio

    2007-01-01

    Adrenomedullin (AM) is a potent vasodilatory peptide originally discovered in human pheochromocytoma tissue. AM and AM gene expression are widely distributed in the cardiovascular system, including the kidney. The co-localization of AM and its receptor components such as calcitonin receptor-like receptor (CRLR), receptor activity modifying protein (RAMP)2 and RAMP3 in the kidney, heart, and vasculature suggests an important role for the peptide as a regulator of renal, cardiac, and vascular function. Indeed, in addition to its cardiovascular effects, AM has renal vasodilatory, natriuretic, and diuretic actions. Consistent with these observations, immunohistochemical studies revealed that AM is stained in the collecting duct, distal convoluted tubules, vessels, and glomerular mesangial cells, endothelial cells and podocytes. Plasma AM levels are increased in patients with renal impairment in proportion to the severity of the disease. Previously we and other investigators showed that two molecular forms of AM, AM-glycine, an inactive form, and AM-mature, an active form, circulate in human plasma. Urine also contains both forms of AM; however, the AM-mature/AM-glycine ratio is higher in urine than in plasma. Interestingly, plasma AM-glycine and AM-mature levels are increased in renal failure, whereas urinary AM-glycine and AM-mature are decreased in this condition. These results indicate that the origin of urinary AM is different from that of plasma AM. Experimental studies showed that the renal tissue AM-mature/AM-glycine ratio is higher than that in plasma and urine. In addition, renal tissue concentrations of AM are increased in severely hypertensive rats. Considering that AM has antiapoptotic, antifibrotic, and antiproliferative effects, the increase of AM in renal disease may be a protective mechanism. In fact, AM gene delivery or long-term AM infusion significantly improved glomerular sclerosis, interstitial fibrosis, and renal arteriosclerosis in several

  2. Pathophysiology of esophageal impairment due to button battery ingestion.

    Science.gov (United States)

    Völker, Johannes; Völker, Christine; Schendzielorz, Philipp; Schraven, Sebastian P; Radeloff, Andreas; Mlynski, Robert; Hagen, Rudolf; Rak, Kristen

    2017-09-01

    The increased use of button batteries with high energy densities in devices of daily life presents a high risk of injury, especially for toddlers and young children. If an accidental ingestion of a button battery occurs, this foreign body can become caught in the constrictions of the esophagus and cause serious damage to the adjacent tissue layers. The consequences can be ulcerations, perforations with fistula formation and damage to the surrounding anatomical structures. In order to gain a better understanding of the pathophysiology after ingestion, we carried out systematic studies on fresh preparations of porcine esophagi. The lithium button battery type CR2032, used most frequently in daily life, was exposed in preparations of porcine esophagi and incubated under the addition of artificial saliva at 37 °C. A total of eight esophagi were analysed by different methods. Measurements of the pH value around the battery electrodes and histological studies of the tissue damage were carried out after 0.5-24 h exposure time. In addition, macroscopic time-lapse images were recorded. Measurements of the battery voltage and the course of the electric current supplemented the experiments. The investigations showed that the batteries caused an electrolysis reaction in the moist environment. The positive electrode formed an acidic and the negative electrode a basic medium. Consequently, a coagulation necrosis at the positive pole, and a deep colliquation necrosis at the minus pole occurred. After an exposure time of 12 h, tissue damage caused by the lye corrosion was observed on the side of the negative electrode up to the lamina muscularis. The corrosion progressed up to the final exposure time of 24 h, but the batteries still had sufficient residual voltage, such that further advancing damage would be expected. Button battery ingestion in humans poses an acute life-threatening danger and immediate endoscopic removal of the foreign body is essential. After only 2

  3. Polarity reversion of the operation mode of HfO2-based resistive random access memory devices by inserting Hf metal layer.

    Science.gov (United States)

    Peng, Ching-Shiang; Chang, Wen-Yuan; Lin, Ming-Ho; Chen, Wei-Su; Chen, Frederick; Tsai, Ming-Jinn

    2013-03-01

    The reversion of polarity within bipolar resistive switching operation occurs in Pt/HfO2/TiN and Pt/Hf/HfO2/TiN resistive random access memory devices. This reversion of voltage polarity is the result of interface generation which induces a conduction mechanism transformation from Poole-Frenkel emission to space charge limited current mechanism. To prove the reversion of polarity, this study uses curve fitting of I-V relations to verify the conduction mechanism theoretically and physical analysis to verify the oxygen ion distribution practically. The proposed Pt/Hf/HfO2/TiN devices exhibit good resistive switching characteristics, such as good uniformity, low voltage operation, robust endurance (10(3) dc sweep), and long retention (3 x 10(4) s at 85 degrees C).

  4. Vertically oriented few-layered HfS2 nanosheets: growth mechanism and optical properties

    Science.gov (United States)

    Zheng, Binjie; Chen, Yuanfu; Wang, Zegao; Qi, Fei; Huang, Zhishuo; Hao, Xin; Li, Pingjian; Zhang, Wanli; Li, Yanrong

    2016-09-01

    For the first time, large-area, vertically oriented few-layered hafnium disulfide (V-{{{HfS}}}2) nanosheets have been grown by chemical vapor deposition. The individual {{{HfS}}}2 nanosheets are well [001] oriented, with highly crystalline quality. Far different from conventional van der Waals epitaxial growth mechanism for two-dimensional transition metal dichalcogenides, a novel dangling-bond-assisted self-seeding growth mechanism is proposed to describe the growth of V-{{{HfS}}}2 nanosheets: difficult migration of {{{HfS}}}2 adatoms on substrate surface results in {{{HfS}}}2 seeds growing perpendicularly to the substrate; V-{{{HfS}}}2 nanosheets inherit the growth direction of {{{HfS}}}2 seeds; V-{{{HfS}}}2 nanosheets further expand in the in-plane direction with time evolution. Moreover, the V-{{{HfS}}}2 nanosheets show strong and broadened photons absorption from near infrared to ultraviolet; the V-{{{HfS}}}2-based photodetector exhibits an ultrafast photoresponse time of 24 ms, and a high photosensitivity ca. 103 for 405 nm laser.

  5. Empirical Study of the Multiaxial, Thermomechanical Behavior of NiTiHf Shape Memory Alloys

    Science.gov (United States)

    Shukla, Dhwanil; Noebe, Ronald D.; Stebner Aaron P.

    2013-01-01

    An empirical study was conducted to characterize the multiaxial, thermomechanical responses of new high temperature NiTiHf alloys. The experimentation included loading thin walled tube Ni(sub 50.3)Ti(sub 29.7)Hf(sub 20) alloy samples along both proportional and nonproportional axial-torsion paths at different temperatures while measuring surface strains using stereo digital image correlation. A Ni(sub 50.3)Ti(sub 33.7)Hf(sub 16) alloy was also studied in tension and compression to document the effect of slightly depleting the Hf content on the constitutive responses of NiTiHf alloys. Samples of both alloys were made from nearly texture free polycrystalline material processed by hot extrusion. Analysis of the data shows that very small changes in composition significantly alter NiTiHf alloy properties, as the austenite finish (Af) temperature of the 16-at Hf alloy was found to be approximately 60 C less than the 20-at Hf alloy (approximately 120 C vs. 180 C). In addition, the 16-at Hf alloy exhibited smaller compressive transformation strains (2 vs. 2.5 percent). Multi-axial characterization of the 20-at % Hf alloy showed that while the random polycrystal transformation strains in tension (4 percent) and compression (2.5 percent) are modest in comparison with binary NiTi (6 percent, 4 percent), the torsion performance is superior (7 vs. 4 shear strain width to the pseudoelastic plateau).

  6. Multifocal motor neuropathy: update on clinical characteristics, pathophysiological concepts and therapeutic options.

    Science.gov (United States)

    Meuth, Sven G; Kleinschnitz, Christoph

    2010-01-01

    Multifocal motor neuropathy (MMN) is an acquired immune-mediated neuropathy characterized by chronic or stepwise progressive asymmetrical limb weakness without sensory deficits. The upper extremities are more often affected than the lower extremities with distal paresis dominating over proximal paresis. Important diagnostic features are persistent multifocal partial conduction blocks (CBs) and the presence of high-titer anti-GM1 serum antibodies. Motor neuron disease, other chronic dysimmune neuropathies, such as chronic inflammatory demyelinating polyneuropathy and the Lewis-Sumner syndrome (MADSAM neuropathy), are important differential diagnoses. While corticosteroids and plasma exchange are largely ineffective, high-dose intravenous immunoglobulins are regarded as first-line treatment. In spite of significant success in elucidating the underlying disease mechanisms in MMN during the past few years, important pathophysiological issues and the optimum long-term therapy remain to be clarified. The present review summarizes the clinical picture and current pathophysiological concepts of MMN with a special focus on the molecular and electrophysiological basis of CBs and highlights established therapies as well as possible novel treatment options.

  7. Effects of HfB2 and HfN Additions on the Microstructures and Mechanical Properties of TiB2-Based Ceramic Tool Materials

    Directory of Open Access Journals (Sweden)

    Jing An

    2017-04-01

    Full Text Available The effects of HfB2 and HfN additions on the microstructures and mechanical properties of TiB2-based ceramic tool materials were investigated. The results showed that the HfB2 additive not only can inhibit the TiB2 grain growth but can also change the morphology of some TiB2 grains from bigger polygons to smaller polygons or longer ovals that are advantageous for forming a relatively fine microstructure, and that the HfN additive had a tendency toward agglomeration. The improvement of flexural strength and Vickers hardness of the TiB2-HfB2 ceramics was due to the relatively fine microstructure; the decrease of fracture toughness was ascribed to the formation of a weaker grain boundary strength due to the brittle rim phase and the poor wettability between HfB2 and Ni. The decrease of the flexural strength and Vickers hardness of the TiB2-HfN ceramics was due to the increase of defects such as TiB2 coarse grains and HfN agglomeration; the enhancement of fracture toughness was mainly attributed to the decrease of the pore number and the increase of the rim phase and TiB2 coarse grains. The toughening mechanisms of TiB2-HfB2 ceramics mainly included crack bridging and transgranular fracture, while the toughening mechanisms of TiB2-HfN ceramics mainly included crack deflection, crack bridging, transgranular fracture, and the core-rim structure.

  8. Crystallography of the NiHfSi Phase in a NiAl (0.5 Hf) Single-Crystal Alloy

    Science.gov (United States)

    Garg, A.; Noebe, R. D.; Darolia, R.

    1996-01-01

    Small additions of Hf to conventionally processed NiAl single crystals result in the precipitation of a high density of cuboidal G-phase along with a newly identified silicide phase. Both of these phases form in the presence of Si which is not an intentional alloying addition but is a contaminant resulting from contact with the ceramic shell molds during directional solidification of the single-crystal ingots. The morphology, crystal structure and Orientation Relationship (OR) of the silicide phase in a NiAl (0.5 at.%Hf) single-crystal alloy have been determined using transmission electron microscopy, electron microdiffraction and energy dispersive X-ray spectroscopy. Qualitative elemental analysis and indexing of the electron microdiffraction patterns from the new phase indicate that it is an orthorhombic NiHfSi phase with unit cell parameters, a = 0.639 nm, b = 0.389 nm and c = 0.72 nm, and space group Pnma. The NiHfSi phase forms as thin rectangular plates on NiAl/111/ planes with an OR that is given by NiHfSi(100))(parallel) NiAl(111) and NiHfSi zone axes(010) (parallel) NiAl zone axes (101). Twelve variants of the NiHfSi phase were observed in the alloy and the number of variants and rectangular morphology of NiHfSi plates are consistent with symmetry requirements. Quenching experiments indicate that nucleation of the NiHfSi phase in NiAI(Hf) alloys is aided by the formation of NiAl group of zone axes (111) vacancy loops that form on the NiAl /111/ planes.

  9. An ab initio study of the C2H2-HF, C2H(CH3)-HF and C2(CH3)2-HF hydrogen-bonded complexes.

    Science.gov (United States)

    Ramos, Mozart N; Lopes, Kelson C; Silva, Washington L V; Tavares, Alessandra M; Castriani, Fátima A; do Monte, Silmar A; Ventura, Elizete; Araújo, Regiane C M U

    2006-02-01

    MP2/6-31++G** and B3LYP/6-31++G** ab initio molecular orbital calculations have been performed in order to obtain molecular geometries, binding energies and vibrational properties of the C2H2-HF, C2H(CH3)-HF and C2(CH3)2-HF H-bonded complexes. As expected, the more pronounced effects on the structural properties of the isolated molecules due to complexation was verified for the C[triple bond]C and H-F bond lengths, which are directly involved in the H-bond formation. These bond distances increased after complexation. BSSE uncorrected B3LYP binding energies are always lower than the corresponding MP2 values. However, the opposite trend has been verified after BSSE correction by the counterpoise method since it is much lower at B3LYP than at MP2 level. The binding energies for these complexes as well as for the HF acid submolecule modes (the HF stretching and vibrational frequency modes) showed an increasing hydrogen-bonding strength with increasing methyl substitution. The splitting in the HF in-plane and out-of-plane bending modes reflects the anisotropy in the hydrogen-bonding interaction with the pi system of the C[triple bond]C bond. The H-F stretching frequency is shifted downward after complexation and it increases with the methyl substitution. The IR intensities of the HF acid submolecule fundamentals are adequately interpreted through the atomic polar tensor of the hydrogen atom using the charge-charge flux-overlap model. The skeletal stretching modes of the Alkyne submolecule are decreased in the complex. The new vibrational modes arising from complexation show several interesting features.

  10. Does human cognition allow Human Factors (HF) certification of advanced aircrew systems?

    Science.gov (United States)

    Macleod, Iain S.; Taylor, Robert M.

    1994-01-01

    This paper has examined the requirements of HF specification and certification within advanced or complex aircrew systems. It suggests reasons for current inadequacies in the use of HF in the design process, giving some examples in support, and suggesting an avenue towards the improvement of the HF certification process. The importance of human cognition to the operation and performance of advanced aircrew systems has been stressed. Many of the shortfalls of advanced aircrew systems must be attributed to over automated designs that show little consideration on either the mental limits or the cognitive capabilities of the human system component. Traditional approaches to system design and HF certification are set within an over physicalistic foundation. Also, traditionally it was assumed that physicalistic system functions could be attributed to either the human or the machine on a one to one basis. Moreover, any problems associated with the parallel needs, or promoting human understanding alongside system operation and direction, were generally equated in reality by the natural flexibility and adaptability of human skills. The consideration of the human component of a complex system is seen as being primarily based on manifestations of human behavior to the almost total exclusion of any appreciation of unobservable human mental and cognitive processes. The argument of this paper is that the considered functionality of any complex human-machine system must contain functions that are purely human and purely cognitive. Human-machine system reliability ultimately depends on human reliability and dependability and, therefore, on the form and frequency of cognitive processes that have to be conducted to support system performance. The greater the demand placed by an advanced aircraft system on the human component's basic knowledge processes or cognition, rather than on skill, the more insiduous the effects the human may have on that system. This paper discusses one

  11. Pathophysiological relationships between heart failure and depression and anxiety.

    Science.gov (United States)

    Chapa, Deborah W; Akintade, Bimbola; Son, Heesook; Woltz, Patricia; Hunt, Dennis; Friedmann, Erika; Hartung, Mary Kay; Thomas, Sue Ann

    2014-04-01

    Depression and anxiety are common comorbid conditions in patients with heart failure. Patients with heart failure and depression have increased mortality. The association of anxiety with increased mortality in patients with heart failure is not established. The purpose of this article is to illustrate the similarities of the underlying pathophysiology of heart failure, depression, and anxiety by using the Biopsychosocial Holistic Model of Cardiovascular Health. Depression and anxiety affect biological processes of cardiovascular function in patients with heart failure by altering neurohormonal function via activation of the hypothalamic-pituitary-adrenal axis, autonomic dysregulation, and activation of cytokine cascades and platelets. Patients with heart failure and depression or anxiety may exhibit a continued cycle of heart failure progression, increased depression, and increased anxiety. Understanding the underlying pathophysiological relationships in patients with heart failure who experience comorbid depression and/or anxiety is critical in order to implement appropriate treatments, educate patients and caregivers, and educate other health professionals.

  12. Pathophysiological basis of pharmacotherapy in the hepatorenal syndrome

    DEFF Research Database (Denmark)

    Møller, Søren; Bendtsen, Flemming; Henriksen, Jens H

    2005-01-01

    Hepatorenal syndrome (HRS) is a functional and reversible impairment of renal function in patients with severe cirrhosis. Major pathophysiological elements include liver dysfunction, a circulatory derangement with central hypovolaemia and neurohumoral activation of potent vasoactive systems leadi...... experimental treatments with endothelin- and adenosine antagonists and long-acting vasoconstrictors may have a future role in the management of HRS.......Hepatorenal syndrome (HRS) is a functional and reversible impairment of renal function in patients with severe cirrhosis. Major pathophysiological elements include liver dysfunction, a circulatory derangement with central hypovolaemia and neurohumoral activation of potent vasoactive systems leading...... to a pronounced renal vasoconstriction. The prognosis of patients with HRS is poor but recent research has spread new enthusiasm for treatment. Efforts at treatment should seek to improve liver function, to ameliorate arterial hypotension and central hypovolaemia, and to reduce renal vasoconstriction. Therefore...

  13. Purple pigments: the pathophysiology of acute porphyric neuropathy.

    Science.gov (United States)

    Lin, Cindy S-Y; Lee, Ming-Jen; Park, Susanna B; Kiernan, Matthew C

    2011-12-01

    The porphyrias are inherited metabolic disorders arising from disturbance in the haem biosynthesis pathway. The neuropathy associated with acute intermittent porphyria (AIP) occurs due to mutation involving the enzyme porphobilinogen deaminase (PBGD) and is characterised by motor-predominant features. Definitive diagnosis often encompasses a combination of biochemical, enzyme analysis and genetic testing, with clinical neurophysiological findings of a predominantly motor axonal neuropathy. Symptomatic and supportive treatment are the mainstays during an acute attack. If administered early, intravenous haemin may prevent progression of neuropathy. While the pathophysiology of AIP neuropathy remains unclear, axonal dysfunction appears intrinsically linked to the effects of neural energy deficits acquired through haem deficiency coupled to the neurotoxic effects of porphyrin precursors. The present review will provide an overview of AIP neuropathy, including discussion of recent advances in understanding developed through neurophysiological approaches that have further delineated the pathophysiology of axonal degeneration.

  14. The pathophysiology of essential tremor and Parkinson's tremor.

    Science.gov (United States)

    Helmich, Rick C; Toni, Ivan; Deuschl, Günther; Bloem, Bastiaan R

    2013-09-01

    We review recent evidence about the pathophysiology of essential tremor and tremor in Parkinson's disease. We believe that a network perspective is necessary to understand this common neurological symptom, and that knowledge of cerebral network dysfunction in tremor disorders will help to develop new therapies. Both essential tremor and Parkinson's tremor are associated with increased activity in the cerebellothalamocortical circuit. However, different pathophysiological mechanisms lead to tremulous activity within this circuit. In Parkinson's disease, evidence suggests that dopaminergic dysfunction of the pallidum triggers increased activity in the cerebellothalamocortical circuit. In essential tremor, GABAergic dysfunction of the cerebellar dentate nucleus and brain stem, possibly caused by neurodegeneration in these regions, may lead to tremulous activity within the cerebellothalamocortical circuit. In both disorders, network parameters such as the strength and directionality of interregional coupling are crucially altered. Exciting new research uses these network parameters to develop network-based therapies, such as closed-loop deep brain stimulation and transcranial magnetic or direct current stimulation.

  15. Facial Erythema of Rosacea - Aetiology, Different Pathophysiologies and Treatment Options.

    Science.gov (United States)

    Steinhoff, Martin; Schmelz, Martin; Schauber, Jürgen

    2016-06-15

    Rosacea is a common chronic skin condition that displays a broad diversity of clinical manifestations. Although the pathophysiological mechanisms of the four subtypes are not completely elucidated, the key elements often present are augmented immune responses of the innate and adaptive immune system, and neurovascular dysregulation. The most common primary feature of all cutaneous subtypes of rosacea is transient or persistent facial erythema. Perilesional erythema of papules or pustules is based on the sustained vasodilation and plasma extravasation induced by the inflammatory infiltrates. In contrast, transient erythema has rapid kinetics induced by trigger factors independent of papules or pustules. Amongst the current treatments for facial erythema of rosacea, only the selective α2-adrenergic receptor agonist brimonidine 0.33% topical gel (Mirvaso®) is approved. This review aims to discuss the potential causes, different pathophysiologies and current treatment options to address the unmet medical needs of patients with facial erythema of rosacea.

  16. Craniosynostosis in Growing Children : Pathophysiological Changes and Neurosurgical Problems

    Science.gov (United States)

    Choi, Jung Won; Lim, So Young

    2016-01-01

    Craniosynostosis is defined as the premature fusion of one or more cranial sutures resulting in skull deformity. Characteristically, this disorder can cause diverse neurosurgical problems, as well as abnormal skull shape. Intracranial hypertension, hydrocephalus, Chiari malformation and neuropsychological dysfunction are the major neurosurgical concerns in children with craniosynostosis. In this review article, we investigate pathophysiology, characteristics and proper neurosurgical management of these neurosurgical issues, respectively. PMID:27226849

  17. Pathophysiological Substantiation of Epidural Administration of Tenoxicam in Dorsalgia Treatment

    OpenAIRE

    Yastrebov D.N.; Shpagin М.V.; Artifexov S.B.

    2012-01-01

    The aim of the investigation is to assess the efficiency of Tenoxicam epidural administration, and represent pathophysiological substantiation of new techniques of dorsalgias treatment. Materials and Methods. There have been examined 75 patients with intense lumbar pain syndrome who underwent epidural pharmacotherapy of pain syndrome. The 1st group (n=50) had epidural Tenoxicam introduction, by 20 mg in 10–20 ml of saline solution, the control group (n=25) was given the combination of cor...

  18. Pathophysiology of pelvic organ prolapse and stress urinary incontinence

    Directory of Open Access Journals (Sweden)

    Payal D Patel

    2006-01-01

    Full Text Available Although they may present with significant morbidity, pelvic organ prolapse and stress urinary incontinence are mainly afflicitions that affect quality of life. To appropiately treat these entities, comprehension of the various theories of pathophysiology is paramount. Utilizing a Medline search, this article reviews recent data concerning intrinsic (i.e., genetics, postmenopausal status and extrinsic factors (i.e., previous hysterectomy, childbirth leading to organ prolapse or stress incontinence

  19. Pathophysiology of Trigger Points in Myofascial Pain Syndrome.

    Science.gov (United States)

    Money, Sarah

    2017-06-01

    Questions from patients about pain conditions and analgesic pharmacotherapy and responses from authors are presented to help educate patients and make them more effective self-advocates. Trigger point pathophysiology in myofascial pain syndrome, which involves muscle stiffness, tenderness, and pain that radiates to other areas of the body, is considered. The causes of trigger points and several theories about how they develop are reviewed, and treatment approaches, including stretching, physical therapy, dry needling, and injections, are offered.

  20. Pathophysiology of Headaches with a Prominent Vascular Component

    Directory of Open Access Journals (Sweden)

    Juan A Pareja

    1996-01-01

    Full Text Available Vascular changes, whether preliminary or secondary, seem to accompany most headaches. The literature concerning pathophysiological mechanisms in headaches where vascular phenomena are a major, integral part, ie, migraine and cluster headache syndrome, is reviewed and the most common forms of headache associated with cerebrovascular disease are discussed. Emphasis is placed on the vascular phenomena and on the abundant hypotheses and theories regarding headache mechanisms. This review also presents alternative explanatory models, and compares the available anatomical, physiological and biochemical results.