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Sample records for blood clot firmness

  1. Blood Clots

    Science.gov (United States)

    ... Index A-Z Blood Clots Blood clots are semi-solid masses of blood that can be stationary (thrombosis) ... treated? What are blood clots? Blood clots are semi-solid masses of blood. Normally, blood flows freely through ...

  2. Blood Clotting and Pregnancy

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    Full Text Available ... Blood Basics Blood Disorders Anemia Bleeding Disorders Blood Cancers Blood Clots Blood Clotting and Pregnancy Clots and ... Increased maternal age Other medical illness (e.g., cancer, infection) back to top How are Blood Clots ...

  3. Blood Clotting and Pregnancy

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    Full Text Available ... For Patients Blood Disorders Blood Clots Blood Clotting & Pregnancy If you are pregnant, or you have just ... The risk of developing a blood clot during pregnancy is increased by the following: Previous blood clots ...

  4. Blood Clotting and Pregnancy

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    Full Text Available ... 6, 2016, San Diego, CA Abstracts Registration Housing Travel Information Government Concierge View all meetings Publications Blood ... Blood Clots Blood Clotting and Pregnancy Clots and Travel DVT Myths vs. Facts Blood Detectives Find a ...

  5. Postpartum Blood Clots

    Science.gov (United States)

    ... Infection Postpartum Blood Clots Postpartum Thyroid Disorders Postpartum Depression The risk of developing blood clots (thrombophlebitis) is increased for about 6 to 8 weeks after delivery (see Thromboembolic Disorders During Pregnancy ). Typically, blood clots occur in the deep veins ...

  6. Blood Clotting and Pregnancy

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    Full Text Available ... back to top How are Blood Clots in Pregnant Women Treated? Typically, blood clots are treated with ... you think you have one. If you are pregnant and have concerns about blood clots, talk with ...

  7. Blood Clots

    Science.gov (United States)

    ... Abstracts Archive View all Education ASH Academy The eLearning platform for hematologists ASH On Demand On-demand ... on the location of the clot and your health. If you are experiencing symptoms and suspect you ...

  8. Blood Clotting and Pregnancy

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    Full Text Available ... raise public awareness of these blood conditions and increase research on the causes, prevention, and treatment. Blood ... of developing a blood clot during pregnancy is increased by the following: Previous blood clots A genetic ...

  9. Blood Clotting and Pregnancy

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    Full Text Available ... San Diego, CA Abstracts Registration Housing Travel Information Government Concierge View all meetings Publications Blood Current Issue ... clot. Blood clots in pregnant women tend to form in the deep veins of the legs or ...

  10. Blood Clotting and Pregnancy

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    Full Text Available ... blood clots A genetic predisposition to blood clots Obesity Prolonged immobility (e.g., bedrest, long distance travel) ... Programs and Awards ASH Agenda for Hematology Research Education For Clinicians For Trainees For Educators For Patients ...

  11. Blood Clotting and Pregnancy

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    Full Text Available ... harming your baby. Jump To: Am I at Risk? The risk of developing a blood clot during pregnancy is ... prevent blood clots during pregnancy: Be aware of risk factors. Know your family history. Make sure your ...

  12. National Blood Clot Alliance

    Science.gov (United States)

    ... Navigation Home About Us Mission & Vision Board of Directors and Officers Medical & Scientific Advisory Board (MASAB) NBCA Operations Programs & Services About Clots Know Your Risk for Blood Clots Signs and Symptoms of Blood ...

  13. Blood Clotting and Pregnancy

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    Full Text Available ... pregnancy: Be aware of risk factors. Know your family history. Make sure your doctor knows about any ... blood clots or blood clotting disorders in your family. Remain active, with your doctor's approval. Be aware ...

  14. Blood Clotting and Pregnancy

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    Full Text Available ... these blood conditions and increase research on the causes, prevention, and treatment. Blood clots are also potentially ... immobility (e.g., bedrest, long distance travel) ...

  15. Blood Clotting and Pregnancy

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    Full Text Available ... About Awards Membership ASH Foundation Global Programs Newsroom facebook twitter youtube linkedin Research In This Section Agenda ... View all publications For Patients Blood Basics Blood Disorders Anemia Bleeding Disorders Blood Cancers Blood Clots Blood ...

  16. Blood Clotting and Pregnancy

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    Full Text Available ... predisposition to blood clots Obesity Prolonged immobility (e.g., bedrest, long distance travel) Multiple births Increased maternal age Other medical illness (e.g., cancer, infection) back to top How are Blood ...

  17. Blood Clotting and Pregnancy

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    Full Text Available ... area. This condition is known as deep vein thrombosis (DVT). Pulmonary embolism (PE) is a life-threatening ... and increase research on the causes, prevention, and treatment. Blood clots are also potentially dangerous to your ...

  18. Blood Clotting and Pregnancy

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    Full Text Available ... genetic predisposition to blood clots Obesity Prolonged immobility (e.g., bedrest, long distance travel) Multiple births Increased maternal age Other medical illness (e.g., cancer, infection) back to top How are ...

  19. Blood Clotting and Pregnancy

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    Full Text Available ... Find a Hematologist Clinical Trials Talking with Your Doctor Patient Group Links Advocacy Toolkit Home For Patients ... factors. Know your family history. Make sure your doctor knows about any history of blood clots or ...

  20. Blood Clotting and Pregnancy

    Medline Plus

    Full Text Available ... your members of Congress to support continued medical research funding Take Action Meetings ASH Workshop on Genome Editing July 14- ... U.S. Surgeon General has issued a Call to Action on DVT and PE to raise public ... research on the causes, prevention, and treatment. Blood clots ...

  1. How Blood Clots

    Science.gov (United States)

    ... 2 Diabetes, Heart Disease a Dangerous Combo Are 'Workaholics' Prone to OCD, Anxiety? ALL NEWS > Resources First ... with clots. Clogged vessels in the brain can cause strokes, and clogged vessels leading to the heart ...

  2. Blood Clotting and Pregnancy

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    Full Text Available ... Research Programs and Awards View all Blood Current Issue First Edition Abstracts Collections Submit to Blood View ... Government Concierge View all meetings Publications Blood Current Issue First Edition Abstracts Blood: How I Treat A ...

  3. Blood Clotting and Pregnancy

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    Full Text Available ... Housing Travel Information Government Concierge View all meetings Publications Blood Current Issue First Edition Abstracts Blood Advances ... reflect the most recent scientific research View all publications For Patients Blood Basics Blood Disorders Anemia Bleeding ...

  4. Blood Clotting and Pregnancy

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    Full Text Available ... in the field Hematology 2015 A collection of articles from the 2015 ASH Annual Meeting Education Program Blood: How I Treat A compendium of Blood articles updated to reflect the most recent scientific research ...

  5. Blood Clotting and Pregnancy

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    Full Text Available ... Current Issue First Edition Abstracts Blood Advances A peer-reviewed, online only, open access journal with a ... If you find that you are interested in learning more about blood diseases and disorders, here are ...

  6. Blood Clotting and Pregnancy

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    Full Text Available ... ASH Apps Share Your Idea Donate My Account Search Show Main Menu + About Awards Membership ASH Foundation ... help: Results of Clinical Studies Published in Blood Search Blood , the official journal of ASH, for the ...

  7. Blood Clotting and Pregnancy

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    Full Text Available ... Advances A peer-reviewed, online only, open access journal with a unique focus on scholarly and educational ... Studies Published in Blood Search Blood , the official journal of ASH, for the results of the latest ...

  8. Blood Clotting and Pregnancy

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    Full Text Available ... Hematologist Clinical Trials Talking with Your Doctor Patient Group Links Advocacy Toolkit Home For Patients Blood Disorders ... a request to the Blood Publishing Office . Patient Groups A list of Web links to patient groups ...

  9. Blood Clotting and Pregnancy

    Medline Plus

    Full Text Available ... Blood: How I Treat A compendium of Blood articles that have been updated to reflect the most ... Sixth Edition Hematology 2015 A collection of review articles from the Education Program at the 2015 ASH ...

  10. Blood Clotting and Pregnancy

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    Full Text Available ... Patients Resources for Industry Professionals View all Guidelines & Quality Care Resources to help practitioners improve patient care ... Concierge View all meetings Publications Blood Current Issue First Edition Abstracts Blood: How I Treat A compendium ...

  11. Blood Clotting and Pregnancy

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    Full Text Available ... Publications Blood Current Issue First Edition Abstracts Blood Advances A peer-reviewed, online only, open access journal with a unique focus on scholarly and educational content The Hematologist Features Diffusion President's Column ASH Clinical News Society News Clinical News Features ASH Self- ...

  12. Blood Clotting and Pregnancy

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    Full Text Available ... Myths vs. Facts Blood Detectives Find a Hematologist Clinical Trials Talking with Your Doctor Patient Group Links Advocacy ... on Genome Editing Publications Blood The Hematologist ASH Clinical News ASH Self-Assessment ... Copyright © 2016 by American Society of Hematology Privacy Policy | Terms of Service | Contact Us

  13. Blood Clotting and Pregnancy

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    Full Text Available ... educational meetings and webinars ASH Image Bank Educational Web-based library of hematologic imagery In This Section: ... Blood Publishing Office . Patient Groups A list of Web links to patient groups and other organizations that ...

  14. Blood Clotting and Pregnancy

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    Full Text Available ... funding Take Action Meetings ASH Meeting on Lymphoma Biology June 18-21, 2016 Further your understanding of ... Malignancies Consultative Hematology Course ASH Meeting on Lymphoma Biology ASH Workshop on Genome Editing Publications Blood The ...

  15. Blood Clotting and Pregnancy

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    Full Text Available ... News Society News Clinical News Features ASH Self-Assessment Program A comprehensive resource to help stay current ... Blood The Hematologist ASH Clinical News ASH Self-Assessment Program Hematology , ASH Education Program About Awards Membership ...

  16. Blood Clotting and Pregnancy

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    Full Text Available ... flow and harming your baby. Jump To: Am I at Risk? The risk of developing a blood ... A Patient's Journey back to top Where Can I Find More Information? If you find that you ...

  17. Blood Clotting and Pregnancy

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    Full Text Available ... First Edition Abstracts Blood Advances A peer-reviewed, online only, open access journal with a unique focus ... ASH ASH Meeting on Hematologic Malignancies Consultative Hematology Course ASH Meeting on Lymphoma Biology ASH Workshop on ...

  18. Blood Clotting and Pregnancy

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    Full Text Available ... Workshop on Genome Editing July 14-15, 2016 Learn new techniques in the clinical application of genome ... If you find that you are interested in learning more about blood diseases and disorders, here are ...

  19. Blood Clotting and Pregnancy

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    Full Text Available ... Clinical News Society News Clinical News Features ASH Self-Assessment Program A comprehensive resource to help stay ... Publications Blood The Hematologist ASH Clinical News ASH Self-Assessment Program Hematology , ASH Education Program About Awards ...

  20. Blood Clotting and Pregnancy

    Medline Plus

    Full Text Available ... 57th ASH Annual Meeting ASH Meeting on Lymphoma Biology June 18-21, 2016 Further your understanding of ... Malignancies Consultative Hematology Course ASH Meeting on Lymphoma Biology ASH Workshop on Genome Editing Publications Blood The ...

  1. Blood Clotting and Pregnancy

    Medline Plus

    Full Text Available ... techniques in the clinical application of genome editing technology MDS Summit Multiple dates and locations A complimentary ... of articles from the 2015 ASH Annual Meeting Education Program Blood: How I Treat A compendium of ...

  2. Blood Clotting and Pregnancy

    Medline Plus

    Full Text Available ... If you find that you are interested in learning more about blood diseases and disorders, here are ... For Patients ASH Academy ASH On Demand ASH Image Bank Advocacy Action Alerts Policy News Advocacy Leadership ...

  3. Blood Clotting and Pregnancy

    Medline Plus

    Full Text Available ... Meeting Abstracts 2016 Call for Abstracts 2016 Abstract Review Categories Abstracts Archive View all Education ASH Academy ... Current Issue First Edition Abstracts Blood Advances A peer-reviewed, online only, open access journal with a ...

  4. Blood Clotting and Pregnancy

    Medline Plus

    Full Text Available ... blood conditions. back to top Antiphospholipid Antibody Syndrome: A Patient's Journey back to top Where Can I ... and help move hematology forward. Learn more Find a Hematologist Search a database of practicing hematologists in ...

  5. Blood Clotting and Pregnancy

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    Full Text Available ... Blood Publishing Office . Patient Groups A list of Web links to patient groups and other organizations that ... Find a Hematologist Search a database of practicing hematologists in your area. ...

  6. Blood Clotting and Pregnancy

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    Full Text Available ... Submit to Blood View all Annual Meeting Abstracts 2016 Call for Abstracts 2016 Abstract Review Categories Abstracts Archive View all Education ... ASH Workshop on Genome Editing July 14-15, 2016 Learn new techniques in the clinical application of ...

  7. Blood Clotting and Pregnancy

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    Full Text Available ... Edition Abstracts Collections Submit to Blood View all Annual Meeting Abstracts 2016 Call for Abstracts 2016 Abstract Review ... Abstracts Registration Housing Schedule and Program 58th ASH ® Annual Meeting & Exposition December 3-6, 2016, San Diego, CA ...

  8. Blood Clotting Inspired Polymer Physics

    Science.gov (United States)

    Sing, Charles Edward

    The blood clotting process is one of the human body's masterpieces in targeted molecular manipulation, as it requires the activation of the clotting cascade at a specific place and a specific time. Recent research in the biological sciences have discovered that one of the protein molecules involved in the initial stages of the clotting response, von Willebrand Factor (vWF), exhibits counterintuitive and technologically useful properties that are driven in part by the physical environment in the bloodstream at the site of a wound. In this thesis, we take inspiration from initial observations of the vWF in experiments, and aim to describe the behaviors observed in this process within the context of polymer physics. By understanding these physical principles, we hope to harness nature's ability to both direct molecules in both spatial and conformational coordinates. This thesis is presented in three complementary sections. After an initial introduction describing the systems of interest, we first describe the behavior of collapsed Lennard-Jones polymers in the presence of an infinite medium. It has been shown that simple bead-spring homopolymer models describe vWF quite well in vitro. We build upon this previous work to first describe the behavior of a collapsed homopolymer in an elongational fluid flow. Through a nucleation-protrusion mechanism, scaling relationships can be developed to provide a clear picture of a first-order globule-stretch transition and its ramifications in dilute-solution rheology. The implications of this behavior and its relation to the current literature provides qualitative explanations for the physiological process of vasoconstriction. In an effort to generalize these observations, we present an entire theory on the behavior of polymer globules under influence of any local fluid flow. Finally, we investigate the internal dynamics of these globules by probing their pulling response in an analogous fashion to force spectroscopy. We elucidate

  9. Cavitation damage in blood clots under HIFU

    Science.gov (United States)

    Weiss, Hope; Ahadi, Golnaz; Hoelscher, Thilo; Szeri, Andrew

    2010-11-01

    High Intensity Focused Ultrasound (HIFU) has been shown to accelerate thrombolysis, the dissolution of blood clots, in vitro and in vivo, for treatment of ischemic stroke. Cavitation in sonothrombolysis is thought to play an important role, although the mechanisms are not fully understood. The damage to a blood clot associated with bubble collapses in a HIFU field is studied. The region of damage caused by a bubble collapse on the fibrin network of the blood clot exposed to HIFU is estimated, and compared with experimental assessment of the damage. The mechanical damage to the network caused by a bubble is probed using two independent approaches, a strain based method and an energy based method. Immunoflourescent fibrin staining is used to assess the region of damage experimentally.

  10. Antithrombin, an Important Inhibitor in Blood Clots.

    Science.gov (United States)

    Zhu, Ying; Cong, Qing-Wei; Liu, Yue; Wan, Chun-Ling; Yu, Tao; He, Guang; He, Lin; Cai, Lei; Chou, Kuo-Chen

    2016-01-01

    Blood coagulation is healthy and lifesaving because it can stop bleeding. It can, however, be a troublemaker as well, causing serious medical problems including heart attack and stroke. Body has complex blood coagulation cascade to modulate the blood clots. In the environment of plasma, the blood coagulation cascade is regulated by antithrombin, which is deemed one of the most important serine protease inhibitors. It inhibits thrombin; it can inhibit factors IXa and Xa as well. Interestingly, its inhibitory ability will be significantly increased with the existence of heparin. In this minireview paper, we are to summarize the structural features of antithrombin, as well as its heparin binding modes and anti-coagulation mechanisms, in hopes that the discussion and analysis presented in this paper can stimulate new strategies to find more effective approaches or compounds to modulate the antithrombin. PMID:26411319

  11. A rat model of reproducible cerebral infarction using thrombotic blood clot emboli

    DEFF Research Database (Denmark)

    Overgaard, K.; Sereghy, T.; Boysen, G.; Pedersen, H.; Høyer, S.; Diemer, Nils Henrik

    Neuropathology, experimental thromboembolism, stroke, blood flow, in vitro thrombotic clotting, cerebral infarction, rat......Neuropathology, experimental thromboembolism, stroke, blood flow, in vitro thrombotic clotting, cerebral infarction, rat...

  12. Limitations of using synthetic blood clots for measuring in vitro clot capture efficiency of inferior vena cava filters

    Directory of Open Access Journals (Sweden)

    Robinson RA

    2013-05-01

    Full Text Available Ronald A Robinson, Luke H Herbertson, Srilekha Sarkar Das, Richard A Malinauskas, William F Pritchard, Laurence W GrossmanOffice of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, MD, USAAbstract: The purpose of this study was first to evaluate the clot capture efficiency and capture location of six currently-marketed vena cava filters in a physiological venous flow loop, using synthetic polyacrylamide hydrogel clots, which were intended to simulate actual blood clots. After observing a measured anomaly for one of the test filters, we redirected the focus of the study to identify the cause of poor clot capture performance for large synthetic hydrogel clots. We hypothesized that the uncharacteristic low clot capture efficiency observed when testing the outlying filter can be attributed to the inadvertent use of dense, stiff synthetic hydrogel clots, and not as a result of the filter design or filter orientation. To study this issue, sheep blood clots and polyacrylamide (PA synthetic clots were injected into a mock venous flow loop containing a clinical inferior vena cava (IVC filter, and their captures were observed. Testing was performed with clots of various diameters (3.2, 4.8, and 6.4 mm, length-to-diameter ratios (1:1, 3:1, 10:1, and stiffness. By adjusting the chemical formulation, PA clots were fabricated to be soft, moderately stiff, or stiff with elastic moduli of 805 ± 2, 1696 ± 10 and 3295 ± 37 Pa, respectively. In comparison, the elastic moduli for freshly prepared sheep blood clots were 1690 ± 360 Pa. The outlying filter had a design that was characterized by peripheral gaps (up to 14 mm between its wire struts. While a low clot capture rate was observed using large, stiff synthetic clots, the filter effectively captured similarly sized sheep blood clots and soft PA clots. Because the stiffer synthetic clots remained straight when approaching the

  13. An optical approach for non-invasive blood clot testing

    Science.gov (United States)

    Kalchenko, Vyacheslav; Brill, Alexander; Fine, Ilya; Harmelin, Alon

    2007-02-01

    Physiological blood coagulation is an essential biological process. Current tests for plasma coagulation (clotting) need to be performed ex vivo and require fresh blood sampling for every test. A recently published work describes a new, noninvasive, in vivo approach to assess blood coagulation status during mechanical occlusion1. For this purpose, we have tested this approach and applied a controlled laser beam to blood micro-vessels of the mouse ear during mechanical occlusion. Standard setup for intravital transillumination videomicroscopy and laser based imaging techniques were used for monitoring the blood clotting process. Temporal mechanical occlusion of blood vessels in the observed area was applied to ensure blood flow cessation. Subsequently, laser irradiation was used to induce vascular micro-injury. Changes in the vessel wall, as well as in the pattern of blood flow, predispose the area to vascular thrombosis, according to the paradigm of Virchow's triad. In our experiments, two elements of Virchow's triad were used to induce the process of clotting in vivo, and to assess it optically. We identified several parameters that can serve as markers of the blood clotting process in vivo. These include changes in light absorption in the area of illumination, as well as changes in the pattern of the red blood cells' micro-movement in the vessels where blood flow is completely arrested. Thus, our results indicate that blood coagulation status can be characterized by non-invasive, in vivo methodologies.

  14. Blood Management Issues: Getting Clots Together When You Want Them

    OpenAIRE

    McMillan, Darryl; Potger, Kieron; Southwell, Joanne

    2011-01-01

    Coagulation is a complex process that allows whole blood to form clots at tissue and vessel sites where damage has occurred. Activation of the hemostasis system causes platelets and fibrin-containing clot to stop the bleeding. Perfusionists must find ways to preserve the coagulation system if we are to avoid bleeding in the cardiopulmonary bypass patient. It is still unclear what techniques are best to continue maintaining hemostasis and avoiding transfusion in patients requiring cardiopulmon...

  15. Clot Retraction: A Miniaturized Hemoretractometer for Blood Clot Retraction Testing (Small 29/2016).

    Science.gov (United States)

    Li, Zida; Li, Xiang; McCracken, Brendan; Shao, Yue; Ward, Kevin; Fu, Jianping

    2016-08-01

    Whole blood coagulation testing provides valuable diagnostic information on diseases such as bleeding disorders, heart attack, deep venous thrombosis, etc. On page 3926, J. Fu and co-workers develop a miniaturized hemoretractometer to measure clot contraction upon blood coagulation with good reproducibility and robustness. This device design shows great application potential in point-of-care testing. Photo credit: David Peyer from University of Michigan. PMID:27477258

  16. Some Important Milestones in the Field of Blood Clotting.

    Science.gov (United States)

    Doolittle, Russell F

    2016-01-01

    Several different kinds of 'milestone' in the field of blood coagulation are described from the middle decades of the 20th century. Although viewed from the standpoint of clotting per se, attention is also given to implications for innate immunity. The first milestone considered is the protracted saga of clotting dependence on vitamin K, an adventure that spanned more than five decades beginning in the 1920s. The second has to do with the discovery of a half-dozen 'new' clotting factors during the period immediately following World War II. A third pursues a narrower focus and examines the once mysterious transformation of fibrinogen into fibrin. Finally, the clinical treatment of classical hemophilia had a remarkable turning point in the 1960s as the result of simple but sensible measures. PMID:26667674

  17. Understand Your Risk for Excessive Blood Clotting

    Science.gov (United States)

    ... Attack • Heart Failure (HF) • Heart Valve Problems and Disease • High Blood Pressure (HBP) • Metabolic Syndrome • Pericarditis • Peripheral Artery Disease (PAD) • Stroke • Venous Thromboembolism (VTE) • Consumer ...

  18. Aggregation of Red Blood Cells: From Rouleaux to Clot Formation

    CERN Document Server

    Wagner, C; Svetina, S

    2013-01-01

    Red blood cells are known to form aggregates in the form of rouleaux. This aggregation process is believed to be reversible, but there is still no full understanding on the binding mechanism. There are at least two competing models, based either on bridging or on depletion. We review recent experimental results on the single cell level and theoretical analyses of the depletion model and of the influence of the cell shape on the binding strength. Another important aggregation mechanism is caused by activation of platelets. This leads to clot formation which is life saving in the case of wound healing but also a major cause of death in the case of a thrombus induced stroke. We review historical and recent results on the participation of red blood cells in clot formation.

  19. Aggregation of red blood cells: From rouleaux to clot formation

    Science.gov (United States)

    Wagner, Christian; Steffen, Patrick; Svetina, Saša

    2013-06-01

    Red blood cells are known to form aggregates in the form of rouleaux. This aggregation process is believed to be reversible, but there is still no full understanding on the adhesion mechanism. There are at least two competing models, based either on bridging or on depletion. We review recent experimental results on the single cell level and theoretical analyses of the depletion model and of the influence of the cell shape on the adhesion strength. Another important aggregation mechanism is caused by activation of platelets. This leads to clot formation which is life-saving in the case of wound healing, but also a major cause of death in the case of a thrombus induced stroke. We review historical and recent results on the participation of red blood cells in clot formation.

  20. Selective Light-Triggered Release of DNA from Gold Nanorods Switches Blood Clotting On and Off

    OpenAIRE

    de Puig, Helena; Cifuentes Rius, Anna; Flemister, Dorma; Salmaan H Baxamusa; Hamad-Schifferli, Kimberly

    2013-01-01

    Blood clotting is a precise cascade engineered to form a clot with temporal and spatial control. Current control of blood clotting is achieved predominantly by anticoagulants and thus inherently one-sided. Here we use a pair of nanorods (NRs) to provide a two-way switch for the blood clotting cascade by utilizing their ability to selectively release species on their surface under two different laser excitations. We selectively trigger release of a thrombin binding aptamer from one nanorod, in...

  1. Mesoscopic Modeling of Blood Clotting: Coagulation Cascade and Platelets Adhesion

    Science.gov (United States)

    Yazdani, Alireza; Li, Zhen; Karniadakis, George

    2015-11-01

    The process of clot formation and growth at a site on a blood vessel wall involve a number of multi-scale simultaneous processes including: multiple chemical reactions in the coagulation cascade, species transport and flow. To model these processes we have incorporated advection-diffusion-reaction (ADR) of multiple species into an extended version of Dissipative Particle Dynamics (DPD) method which is considered as a coarse-grained Molecular Dynamics method. At the continuum level this is equivalent to the Navier-Stokes equation plus one advection-diffusion equation for each specie. The chemistry of clot formation is now understood to be determined by mechanisms involving reactions among many species in dilute solution, where reaction rate constants and species diffusion coefficients in plasma are known. The role of blood particulates, i.e. red cells and platelets, in the clotting process is studied by including them separately and together in the simulations. An agonist-induced platelet activation mechanism is presented, while platelets adhesive dynamics based on a stochastic bond formation/dissociation process is included in the model.

  2. High-speed shaking of frozen blood clots for extraction of human and malaria parasite DNA

    OpenAIRE

    Mohammed Adan; Lebbad Marianne; Macharia Alex; Lundblom Klara; Färnert Anna

    2011-01-01

    Abstract Background Frozen blood clots remaining after serum collection is an often disregarded source of host and pathogen DNA due to troublesome handling and suboptimal outcome. Methods High-speed shaking of clot samples in a cell disruptor manufactured for homogenization of tissue and faecal specimens was evaluated for processing frozen blood clots for DNA extraction. The method was compared to two commercial clot protocols based on a chemical kit and centrifugation through a plastic sieve...

  3. Selective light-triggered release of DNA from gold nanorods switches blood clotting on and off.

    Directory of Open Access Journals (Sweden)

    Helena de Puig

    Full Text Available Blood clotting is a precise cascade engineered to form a clot with temporal and spatial control. Current control of blood clotting is achieved predominantly by anticoagulants and thus inherently one-sided. Here we use a pair of nanorods (NRs to provide a two-way switch for the blood clotting cascade by utilizing their ability to selectively release species on their surface under two different laser excitations. We selectively trigger release of a thrombin binding aptamer from one nanorod, inhibiting blood clotting and resulting in increased clotting time. We then release the complementary DNA as an antidote from the other NR, reversing the effect of the aptamer and restoring blood clotting. Thus, the nanorod pair acts as an on/off switch. One challenge for nanobiotechnology is the bio-nano interface, where coronas of weakly adsorbed proteins can obscure biomolecular function. We exploit these adsorbed proteins to increase aptamer and antidote loading on the nanorods.

  4. Selective light-triggered release of DNA from gold nanorods switches blood clotting on and off.

    Science.gov (United States)

    de Puig, Helena; Cifuentes Rius, Anna; Flemister, Dorma; Baxamusa, Salmaan H; Hamad-Schifferli, Kimberly

    2013-01-01

    Blood clotting is a precise cascade engineered to form a clot with temporal and spatial control. Current control of blood clotting is achieved predominantly by anticoagulants and thus inherently one-sided. Here we use a pair of nanorods (NRs) to provide a two-way switch for the blood clotting cascade by utilizing their ability to selectively release species on their surface under two different laser excitations. We selectively trigger release of a thrombin binding aptamer from one nanorod, inhibiting blood clotting and resulting in increased clotting time. We then release the complementary DNA as an antidote from the other NR, reversing the effect of the aptamer and restoring blood clotting. Thus, the nanorod pair acts as an on/off switch. One challenge for nanobiotechnology is the bio-nano interface, where coronas of weakly adsorbed proteins can obscure biomolecular function. We exploit these adsorbed proteins to increase aptamer and antidote loading on the nanorods. PMID:23894311

  5. A simple and efficient method for DNA purification from samples of highly clotted blood.

    Science.gov (United States)

    Xu, Ruyi; Ye, Ping; Luo, Leiming; Wu, Hongmei; Dong, Jin; Deng, Xinxin

    2010-11-01

    Rapid purification of DNA from samples of highly clotted blood is a challenging problem due to the difficulty in recovering and dispersing blood clots. We developed a new method for discarding the serum-separator gel and rapidly dispersing the blood clots. A special disposable tip was inserted into the serum-separator gel so that the serum-separator gel could be discarded. The blood clot obtained was dispersed into small pieces through a copper mesh (pore size, 250 μm) in a special dispersing instrument by centrifugation. After lysis of red blood cells and white blood cells, genomic DNA was concentrated and desalted by isopropanol precipitation. The mean yield of DNA purified from a 0.3-ml blood clot was 22.70 μg in 173 samples of clotted blood cryopreserved for 1 month, and 19.02 μg in 1,372 samples of clotted blood cryopreserved for >6 months. DNA samples were successfully performed through polymerase chain reaction, real time polymerase chain reaction, and melt curve analysis. Their quality was comparable with that purified directly from EDTA-anticoagulated blood. The new method overcomes the difficulties in recovering and dispersing blood clots, allowing efficient purification of DNA from samples of highly clotted blood. PMID:20549389

  6. Adenosine diphosphate-decorated chitosan nanoparticles shorten blood clotting times, influencing the structures and varying the mechanical properties of the clots.

    Science.gov (United States)

    Chung, Tze-Wen; Lin, Pei-Yi; Wang, Shoei-Shen; Chen, Yen-Fung

    2014-01-01

    Chitosan nanoparticles (NPs) decorated with adenosine diphosphate (ADP) (ANPs) or fibrinogen (FNPs) were used to fabricate hemostatic NPs that can shorten blood clotting time and prevent severe local hemorrhage. The structure and mechanical properties of the blood clot induced with ANP (clot/ANP) or FNP (clot/FNP) were also investigated. The NPs, ANPs, and FNPs, which had particle sizes of 245.1 ± 14.0, 251.0 ± 9.8, and 326.5 ± 14.5 nm and zeta potentials of 24.1 ± 0.5, 20.6 ± 1.9, and 15.3 ± 1.5 mV (n=4), respectively, were fabricated by ionic gelation and then decorated with ADP and fibrinogen. The zeta potentials and Fourier transform infrared (FTIR) spectroscopy of the NPs confirmed that their surfaces were successfully coated with ADP and fibrinogen. The scanning electron microscope (SEM) micrographs of the structure of the clot induced with "undecorated" chitosan NPs (clot/NP), clot/ANP, and clot/FNP (at 0.05 wt%) were different, after citrated bloods had been recalcified by a calcium chloride solution containing NPs, ANPs, or FNPs. This indicated that many NPs adhered on the membrane surfaces of red blood cells, that ANPs induced many platelet aggregates, and that FNPs were incorporated into the fibrin network in the clots. Measurements of the blood clotting times (Tc) of blood clot/NPs, clot/ANPs, and clot/FNPs, based on 90% of ultimate frequency shifts measured on a quartz crystal microbalance (QCM), were significantly (Pcompressibility in clot/NPs and clot/ANPs (Pcompression flow properties of the clot. Hence, ANPs have potential applications for preventing severe local hemorrhage. PMID:24729701

  7. Capture of lipopolysaccharide (endotoxin by the blood clot: a comparative study.

    Directory of Open Access Journals (Sweden)

    Margaret T Armstrong

    Full Text Available In vertebrates and arthropods, blood clotting involves the establishment of a plug of aggregated thrombocytes (the cellular clot and an extracellular fibrillar clot formed by the polymerization of the structural protein of the clot, which is fibrin in mammals, plasma lipoprotein in crustaceans, and coagulin in the horseshoe crab, Limulus polyphemus. Both elements of the clot function to staunch bleeding. Additionally, the extracellular clot functions as an agent of the innate immune system by providing a passive anti-microbial barrier and microbial entrapment device, which functions directly at the site of wounds to the integument. Here we show that, in addition to these passive functions in immunity, the plasma lipoprotein clot of lobster, the coagulin clot of Limulus, and both the platelet thrombus and the fibrin clot of mammals (human, mouse operate to capture lipopolysaccharide (LPS, endotoxin. The lipid A core of LPS is the principal agent of gram-negative septicemia, which is responsible for more than 100,000 human deaths annually in the United States and is similarly toxic to arthropods. Quantification using the Limulus Amebocyte Lysate (LAL test shows that clots capture significant quantities of LPS and fluorescent-labeled LPS can be seen by microscopy to decorate the clot fibrils. Thrombi generated in the living mouse accumulate LPS in vivo. It is suggested that capture of LPS released from gram-negative bacteria entrapped by the blood clot operates to protect against the disease that might be caused by its systemic dispersal.

  8. Rapid and simple method for preparation of genomic DNA from easily obtainable clotted blood.

    OpenAIRE

    Kanai, N; Fujii, T.; Saito, K; Tokoyama, T

    1994-01-01

    A method was developed for the preparation of genomic DNA from clotted blood that is usually discarded after extraction, for other laboratory tests. The method, which involves proteinase K digestion, salt/chloroform extraction and 90% ethanol precipitation of DNA from clotted blood, is rapid, simple, and easy because it does not impose an extra burden on the patient.

  9. 42 CFR 410.63 - Hepatitis B vaccine and blood clotting factors: Conditions.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Hepatitis B vaccine and blood clotting factors... Other Health Services § 410.63 Hepatitis B vaccine and blood clotting factors: Conditions... under § 410.10, subject to the specified conditions: (a) Hepatitis B vaccine: Conditions....

  10. High-speed shaking of frozen blood clots for extraction of human and malaria parasite DNA

    Directory of Open Access Journals (Sweden)

    Mohammed Adan

    2011-08-01

    Full Text Available Abstract Background Frozen blood clots remaining after serum collection is an often disregarded source of host and pathogen DNA due to troublesome handling and suboptimal outcome. Methods High-speed shaking of clot samples in a cell disruptor manufactured for homogenization of tissue and faecal specimens was evaluated for processing frozen blood clots for DNA extraction. The method was compared to two commercial clot protocols based on a chemical kit and centrifugation through a plastic sieve, followed by the same DNA extraction protocol. Blood clots with different levels of parasitaemia (1-1,000 p/μl were prepared from parasite cultures to assess sensitivity of PCR detection. In addition, clots retrieved from serum samples collected within two epidemiological studies in Kenya (n = 630 were processed by high speed shaking and analysed by PCR for detection of malaria parasites and the human α-thalassaemia gene. Results High speed shaking succeeded in fully dispersing the clots and the method generated the highest DNA yield. The level of PCR detection of P. falciparum parasites and the human thalassaemia gene was the same as samples optimally collected with an anticoagulant. The commercial clot protocol and centrifugation through a sieve failed to fully dissolve the clots and resulted in lower sensitivity of PCR detection. Conclusions High speed shaking was a simple and efficacious method for homogenizing frozen blood clots before DNA purification and resulted in PCR templates of high quality both from humans and malaria parasites. This novel method enables genetic studies from stored blood clots.

  11. Honey Bee Venom (Apis mellifera) Contains Anticoagulation Factors and Increases the Blood-clotting Time

    OpenAIRE

    Hossein Zolfagharian; Mohammad Mohajeri; Mahdi Babaie

    2015-01-01

    Objectives: Bee venom (BV) is a complex mixture of proteins and contains proteins such as phospholipase and melittin, which have an effect on blood clotting and blood clots. The mechanism of action of honey bee venom (HBV, Apis mellifera) on human plasma proteins and its anti-thrombotic effect were studied. The purpose of this study was to investigate the anti-coagulation effect of BV and its effects on blood coagulation and purification. Methods: Crude venom obtained from Apis mellifera was ...

  12. Blood Clots and Travel: What You Need to Know

    Science.gov (United States)

    ... Related Links Yellow Book chapter on DVT and travel Facts Clot Connect World Health Organization Information For... Media Policy Makers Language: English Español (Spanish) File Formats Help: How do I view different file formats (PDF, ...

  13. Adenosine diphosphate-decorated chitosan nanoparticles shorten blood clotting times, influencing the structures and varying the mechanical properties of the clots

    Directory of Open Access Journals (Sweden)

    Chung TW

    2014-03-01

    Full Text Available Tze-Wen Chung,1,3 Pei-Yi Lin,2 Shoei-Shen Wang,2 Yen-Fung Chen31Department of Biomedical Engineering, National Yang-Ming University, 2Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan, Republic of China; 3Department of Chemical and Materials Engineering, National Yunlin University of Science and Technology, Yunlin, Taiwan, Republic of ChinaAbstract: Chitosan nanoparticles (NPs decorated with adenosine diphosphate (ADP (ANPs or fibrinogen (FNPs were used to fabricate hemostatic NPs that can shorten blood clotting time and prevent severe local hemorrhage. The structure and mechanical properties of the blood clot induced with ANP (clot/ANP or FNP (clot/FNP were also investigated. The NPs, ANPs, and FNPs, which had particle sizes of 245.1±14.0, 251.0±9.8, and 326.5±14.5 nm and zeta potentials of 24.1±0.5, 20.6±1.9, and 15.3±1.5 mV (n=4, respectively, were fabricated by ionic gelation and then decorated with ADP and fibrinogen. The zeta potentials and Fourier transform infrared (FTIR spectroscopy of the NPs confirmed that their surfaces were successfully coated with ADP and fibrinogen. The scanning electron microscope (SEM micrographs of the structure of the clot induced with "undecorated" chitosan NPs (clot/NP, clot/ANP, and clot/FNP (at 0.05 wt% were different, after citrated bloods had been recalcified by a calcium chloride solution containing NPs, ANPs, or FNPs. This indicated that many NPs adhered on the membrane surfaces of red blood cells, that ANPs induced many platelet aggregates, and that FNPs were incorporated into the fibrin network in the clots. Measurements of the blood clotting times (Tc of blood clot/NPs, clot/ANPs, and clot/FNPs, based on 90% of ultimate frequency shifts measured on a quartz crystal microbalance (QCM, were significantly (P<0.05 (n=4 shorter than that of a clot induced by a phosphate-buffered solution (PBS (clot/PBS (63.6%±3.1%, 48.3%±6.2%, and 63.2%±4.7%, respectively. The ∆F2

  14. Blood Clots That Kill: Preventing DVT | NIH MedlinePlus the Magazine

    Science.gov (United States)

    ... This also is true of treatment with hormone therapy or birth control pills. Sometimes, blood clots can form from no known cause. Risk Many factors increase your risk for deep vein thrombosis (DVT). They include: A history of DVT. Disorders ...

  15. Iodine based radiopacity of experimental blood clots for testing of mechanical thrombectomy devices

    International Nuclear Information System (INIS)

    Barium sulfate powder used for radiopacity of experimental blood clots (EBCs) for testing mechanical thrombectomy devices (MTD) has negative effects on EBCs mechanical properties. In vitro and in vivo exploration was performed to determine if the iodine based contrast medium will have less negative effects on the EBCs than barium. Fresh blood from 2 swine was used to create fibrinogen enhanced and thrombin initiated EBC in tubes. Iodine radiopacity was achieved by mixing the blood with 65% Iohexol or by soaking the EBCs for 2 or 24 hours in Iohexol. The EBCs opacified with barium served as controls. In vitro study: The EBCs were subjected to four tests, manual elongation, catheter injection, radiopacity and contrast wash out tests. In vivo study: The common carotid arteries of 2 swine were embolized by either barium EBC or EBC soaked for 24 hours in Iohexol. The duration of radiopacity of the different EBCs was compared. The EBCs opacified with Iohexol initially had higher radiopacity than the barium opacified EBCs. However, their opacity rapidly decreased with saline soaking and, particularly, after they were embolized in live animals. The mechanical properties of Iohexol opacified EBCs were inferior to barium opacified EBCs. The Iohexol mixed EBCs were less firm and elastic and half of them fragmented during catheter injection. The Iohexol soaked EBCs exhibited decreased tensile strength and elasticity compared to the barium EBCs. Compared to barium, iodine based contrast medium does not offer any advantage for opacifying EBCs

  16. Reflectance changes in clotting native blood: evidence of a red-cell process.

    Science.gov (United States)

    Greco, Frank A

    2007-01-01

    When broadband light illuminates clotting native blood, the reflectance at each wavelength traces a time course with four discernible regions. Clot formation occurs just before the second phase. Two wavelengths, 471 and 771 nm, were selected for more detailed study of the first two phases. Analysis of each time course in native blood demonstrates that both signals track a single process during the first phase, but distinct processes during the second. Experiments on citrated blood identified which blood components contribute to reflectance changes. Comparison of liquid and clotting blood reveals a single process during the first phase, entailing that rouleaux formation determines the time course at both wavelengths. Control experiments eliminate clot propagation and shape change of red cells or platelets as possible factors in the second phase. Exogenous ADP added to EDTA blood evokes the second-phase response at 471 but not 771 nm, a novel phenomenon that requires the presence of red cells. The descriptive name 'ADP-end-response' is suggested for this red cell process until it is further characterized. We propose that the ADP-end-response determines the 471-nm signal during the second phase of clotting native blood and depends upon platelets in the absence of exogenous ADP. The 771-nm signal reports fibrin cross-linking during the second phase. An earlier pilot study demonstrated that rofecoxib effects the 471-nm signal ex vivo, which indicates that reflectance spectroscopy may be useful in the assessment of drug effects on platelet-erythrocyte interactions. PMID:18332611

  17. Comparison of Bleeding Time and Clotting Time in Different Blood Groups

    Directory of Open Access Journals (Sweden)

    B. Mahapatra

    2009-01-01

    Full Text Available Problem statement: Researchers have demonstrated that epistaxis is more often encountered in patients having blood group O probably due to lower expression of von Willebrand factor. We had taken up this study to find out if there is any definite relationship between the blood groups with the bleeding time and clotting time in our population. Approach: This retrospective study was conducted in the department of physiology in our institution. The available detail reports of 740 students passing through 1st year of MBBS over the years from 1999-2007 were analyzed in respect of age, sex, blood groups, bleeding time and clotting time. The blood grouping was done with the standard antisera and bleeding time and clotting time were estimated by Duke method and capillary tube method respectively. Finally bleeding time and clotting time of different blood groups were compared and statistical analysis was done. Results: In present study population O group was found in more number of cases (37.8% than A, B and AB. Clotting time was found to be prolonged more than 6 min in maximum number of cases in B group (12.7 cases followed by A group (8 and O group (5.8 and AB group (4.3%. Similarly bleeding time was more than 4 min in AB group in 21.8 followed by 13.9 in group B, 10.5 in group A and 9.6% in group O. Conclusion: In present study population interestingly clotting time was more in blood group AB and bleeding time in blood group B than other blood groups which was statistically significant. Further study needed to correlate the association of this finding in cases of epistaxis and hemoptysis in our population.

  18. Effect of thiol derivatives on mixed mucus and blood clots in vitro.

    Science.gov (United States)

    Risack, L E; Vandevelde, M E; Gobert, J G

    1978-01-01

    The disintegrating effect of three reducing thiol derivatives: [sodium mercaptoethane sulphonate (Mesna), N-acetyl-L-cysteine (NAC) and dithio-1,4-threitol (DTT)] was investigated in vitro upon blood clots formed in the absence or in the presence of tracheobronchial secretions and compared with the effect of iso-osmotic saline solution. The amounts of haemoglobin released from the clots after 30 min incubation and the initial rates of haemoglobin release were compared for the different products at different concentrations. All three reducing agents showed some ability to disintegrate mixed clots to an extent depending on their concentration. After 30 min incubation, statistical analysis showed a highly significant difference in favour of Mesna at the three concentrations used, i.e. 0.1, 1.0 and 10 mmol/1. The initial rate of haemoglobin release in presence of Mesna was at all concentrations significantly higher than that of NAC or DTT. The effects on normal blood clots were much less pronounced. The effectiveness of Mesna in splitting up mixed blood and mucus clots in the management of patients who had inhaled blood is discussed. PMID:97741

  19. Honey Bee Venom (Apis mellifera Contains Anticoagulation Factors and Increases the Blood-clotting Time

    Directory of Open Access Journals (Sweden)

    Hossein Zolfagharian

    2015-12-01

    Full Text Available Objectives: Bee venom (BV is a complex mixture of proteins and contains proteins such as phospholipase and melittin, which have an effect on blood clotting and blood clots. The mechanism of action of honey bee venom (HBV, Apis mellifera on human plasma proteins and its anti-thrombotic effect were studied. The purpose of this study was to investigate the anti-coagulation effect of BV and its effects on blood coagulation and purification. Methods: Crude venom obtained from Apis mellifera was selected. The anti-coagulation factor of the crude venom from this species was purified by using gel filtration chromatography (sephadex G-50, and the molecular weights of the anti-coagulants in this venom estimated by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE. Blood samples were obtained from 10 rabbits, and the prothrombin time (PT and the partial thromboplastin time (PTT tests were conducted. The approximate lethal dose (LD values of BV were determined. Results: Crude BV increased the blood clotting time. For BV concentrations from 1 to 4 mg/mL, clotting was not observed even at more than 300 seconds, standard deviations (SDs = ± 0.71; however, clotting was observed in the control group 13.8 s, SDs = ± 0.52. Thus, BV can be considered as containing anti-coagulation factors. Crude BV is composed 4 protein bands with molecular weights of 3, 15, 20 and 41 kilodalton (kDa, respectively. The LD50 of the crude BV was found to be 177.8 μg/mouse. Conclusion: BV contains anti-coagulation factors. The fraction extracted from the Iranian bees contains proteins that are similar to anti-coagulation proteins, such as phospholipase A2 (PLA2 and melittin, and that can increase the blood clotting times in vitro.

  20. In vitro sonothrombolysis of human blood clots with BR38 microbubbles.

    Science.gov (United States)

    Petit, Bénédicte; Gaud, Emmanuel; Colevret, Delphine; Arditi, Marcel; Yan, Feng; Tranquart, François; Allémann, Eric

    2012-07-01

    Microbubble-mediated sonothrombolysis is a promising approach for ischemic stroke treatment. The aim of this in vitro study was to evaluate a new microbubble (MB) formulation (BR38) for sonothrombolysis and to investigate the involved mechanisms. Human whole-blood clots were exposed to different combinations of recombinant tissue plasminogen activator (rtPA), ultrasound (US) and MB. Ultrasound at 1.6 MHz was used at 150, 300, 600 and 1000 kPa (peak-negative pressure). Thrombolysis efficacy was assessed by measuring clot diameter changes during 60-min US exposure. The rate of clot diameter loss (RDL) in μm/min was determined and clot lysis profiles were analyzed. The most efficient clot lysis (5.9 μm/min) was obtained at acoustic pressures of 600 and 1000 kPa in combination with MB and a low concentration of rtPA (0.3 μg/mL). This is comparable with the rate obtained with rtPA at 3 μg/mL alone (6.6 μm/min, p > 0.05). Clot lysis profiles were shown to be related to US beam profiles and microbubble cavitation. PMID:22542261

  1. High-Quality and -Quantity DNA Extraction from Frozen Archival Blood Clots for Genotyping of Single-Nucleotide Polymorphisms

    DEFF Research Database (Denmark)

    Bank, Steffen; Nexø, Bjørn Andersen; Andersen, Vibeke;

    2013-01-01

    Background: The recovery of biological samples for genetic epidemiological studies can be cumbersome. Blood clots are routinely collected for serological examinations. However, the extraction of DNA from blood clots can be difficult and often results in low yields. Aim: The aim was to compare the...

  2. Blood Clotting and Coagulation Factors: The Work of Yale Nemerson

    OpenAIRE

    Kresge, Nicole; Simoni, Robert D.; Hill, Robert L.

    2011-01-01

    After developing a blood disorder, Yale Nemerson became interested in hematology. This led to his lifelong study of thrombogenic tissue factor and to his contributions to developing the modern theory of blood coagulation. The two Classic papers reprinted here detail some of Nemerson's studies on coagulation factors IX and VII.

  3. Aggregation of Red Blood Cells: From Rouleaux to Clot Formation

    OpenAIRE

    Wagner, C.; Steffen, P.; Svetina, S

    2013-01-01

    Red blood cells are known to form aggregates in the form of rouleaux. This aggregation process is believed to be reversible, but there is still no full understanding on the binding mechanism. There are at least two competing models, based either on bridging or on depletion. We review recent experimental results on the single cell level and theoretical analyses of the depletion model and of the influence of the cell shape on the binding strength. Another important aggregation mechanism is caus...

  4. Investigation of adverse effects of interactions between herbal drugs and natural blood clotting mechanism.

    Science.gov (United States)

    Adhyapak, M S; Kachole, M S

    2016-05-01

    Throughout the world, herbal medicines are consumed by most of the patients without considering their adverse effects. Many herbal medicines/plant extracts have been reported to interact with the natural blood clotting system. In continuation to this effort, thirty medicinal plant extracts were allowed to interact with citrated human blood and the clotting time was measured after re-calcification in vitro using Lee and White method. The aq. leaf ext. of Syzygium cumini and Camellia sinensis significantly prolonged the clotting time. In response to the prothrombin time and activated partial thromboplastin time tests, the ext. of C. sinensis showed normal APTT and marginally prolonged the PT to 16.7 s (control-15.2 s) while S. cumini showed normal PT but significantly prolonged the APTT to 66.9 s (control-20.7 s). This suggests that, C. sinensis acts on the extrinsic pathway while S. cumini on the intrinsic pathway. There are some common herbal formulations that are frequently used by the patients which contain above plant materials, like, Syzygium cumin in anti-diabetic formulations, while the ext. of C. sinensis is consumed frequently as beverage in many part of the world. Hence, patients having known bleeding tendency or haemophilia disease should take into account the interaction potential of these plants with the natural blood clotting system while taking herbal formulations containing above plants; specially, the patients suffering from intrinsic pathway factor deficiency should keep a limit on the consumption of S. cumini while extrinsic pathway factor deficiency patients should limit C. sinensis. Also, the medical practitioners should consider the patient's food consumption history before doing any major surgical procedures. PMID:26340850

  5. Alkali treatment of microrough titanium surfaces affects macrophage/monocyte adhesion, platelet activation and architecture of blood clot formation

    Directory of Open Access Journals (Sweden)

    V Milleret

    2011-05-01

    Full Text Available Titanium implants are most commonly used for bone augmentation and replacement due to their favorable osseointegration properties. Here, hyperhydrophilic sand-blasted and acid-etched (SBA titanium surfaces were produced by alkali treatment and their responses to partially heparinized whole human blood were analyzed. Blood clot formation, platelet activation and activation of the complement system was analyzed revealing that exposure time between blood and the material surface is crucial as increasing exposure time results in higher amount of activated platelets, more blood clots formed and stronger complement activation. In contrast, the number of macrophages/monocytes found on alkali-treated surfaces was significantly reduced as compared to untreated SBA Ti surfaces. Interestingly, when comparing untreated to modified SBA Ti surfaces very different blood clots formed on their surfaces. On untreated Ti surfaces blood clots remain thin (below 15 mm, patchy and non-structured lacking large fibrin fiber networks whereas blood clots on differentiated surfaces assemble in an organized and layered architecture of more than 30 mm thickness. Close to the material surface most nucleated cells adhere, above large amounts of non-nucleated platelets remain entrapped within a dense fibrin fiber network providing a continuous cover of the entire surface. These findings might indicate that, combined with findings of previous in vivo studies demonstrating that alkali-treated SBA Ti surfaces perform better in terms of osseointegration, a continuous and structured layer of blood components on the blood-facing surface supports later tissue integration of an endosseous implant.

  6. Study of garlic effect on fibrinolytic activity of the blood clot in vitro

    Directory of Open Access Journals (Sweden)

    Ansari.F

    Full Text Available IntroductionThe main function of the fibrinolytic system is to dissolve fibrin clots in circulation. This system is composed of inactive precursor plasminogen which can be converted into plasmin by the proteolytic enzymes like tissue-type plasminogen activator (tPA. Fibrinolytic properties can be found in a variety of medicine plants and they could effectively prevent cardiovascular diseases (CVD. One of these medicine plants is Allium sativum, which was used for its antiplatlet and fibrinolytic effects in patients with CVD (garlic.This study considers to find the fibrinolytic effect of the various concentration of garlic extract and the time of the most effect.MethodsGarlic extracts were prepared using 70% ethanol, and labeling fibrinogen with fluorescent agent to create a labeled clot. Then 10, 25 and 50μg/μl of garlic extract were separately added to plasma environment and finally the labeled clots were inserted. At the end fluorescence intensity of the supernatant was measured. The data were analyzed using SPSS (version 16.ResultsThe results indicated that garlic extract showed fibrinolytic effect significantly compared with the control group (p<0.05. Various concentrations of garlic extract showed significant different rise in the fibrinolytic activity of blood clot in different time (p<0.05. Desirable result obtained in the lower concentration of (10μg/μl after 7 hours.ConclusionGarlic extract displayed the fibrinolytic activity which concentration and time factors of exposure influenced it but the minimum concentration and the maximum time showed the best result.

  7. Addition of a sequence from α2-antiplasmin transforms human serum albumin into a blood clot component that speeds clot lysis

    Directory of Open Access Journals (Sweden)

    Gataiance Sharon

    2009-03-01

    Full Text Available Abstract Background The plasma protein α2-antiplasmin (α2AP is cross-linked to fibrin in blood clots by the transglutaminase factor XIIIa, and in that location retards clot lysis. Competition for this effect could be clinically useful in patients with thrombosis. We hypothesized that fusion of N-terminal portions of α2-antiplasmin to human serum albumin (HSA and production of the chimeric proteins in Pichia pastoris yeast would produce a stable and effective competitor protein. Results Fusion protein α2AP(13-42-HSA was efficiently secreted from transformed yeast and purified preparations contained within a mixed population the full-length intact form, while fusions with longer α2AP moieties were inefficiently secreted and/or degraded. The α2AP(13-42-HSA protein, but not recombinant HSA, was cross-linked to both chemical lysine donors and fibrin or fibrinogen by factor XIIIa, although with less rapid kinetics than native α2AP. Excess α2AP(13-42-HSA competed with α2AP for cross-linking to chemical lysine donors more effectively than a synthetic α2AP(13-42 peptide, and reduced the α2AP-dependent resistance to fibrinolysis of plasma clots equally effectively as the peptide. Native α2AP was found in in vivo clots in rabbits to a greater extent than α2AP(13-42, however. Conclusion In this first report of transfer of transglutamination substrate status from one plasma protein to another, fusion protein α2AP(13-42-HSA was shown to satisfy initial requirements for a long-lasting, well-tolerated competitive inhibitor of α2-antiplasmin predicted to act in a clot-localized manner.

  8. Continuous and semi-continuous cell culture for production of blood clotting factors.

    Science.gov (United States)

    Desai, Sunil G

    2015-11-10

    Recombinant clotting factors are important biotherapeutics that Pfizer has produced and marketed for over fifteen years. Owing to the complexity of the structure and function of these blood factors, it can be challenging to achieve the required product quality and manufacturing productivity. The article highlights the semi-continuous and continuous cell culture processes employed by Pfizer for the production of BeneFIX and ReFacto AF. The benefits of such processes, the challenges of maintaining an aseptic production culture for extended periods, and batch definition are discussed in this article. PMID:25738489

  9. A portable blood plasma clot micro-elastometry device based on resonant acoustic spectroscopy

    Science.gov (United States)

    Krebs, C. R.; Li, Ling; Wolberg, Alisa S.; Oldenburg, Amy L.

    2015-07-01

    Abnormal blood clot stiffness is an important indicator of coagulation disorders arising from a variety of cardiovascular diseases and drug treatments. Here, we present a portable instrument for elastometry of microliter volume blood samples based upon the principle of resonant acoustic spectroscopy, where a sample of well-defined dimensions exhibits a fundamental longitudinal resonance mode proportional to the square root of the Young's modulus. In contrast to commercial thromboelastography, the resonant acoustic method offers improved repeatability and accuracy due to the high signal-to-noise ratio of the resonant vibration. We review the measurement principles and the design of a magnetically actuated microbead force transducer applying between 23 pN and 6.7 nN, providing a wide dynamic range of elastic moduli (3 Pa-27 kPa) appropriate for measurement of clot elastic modulus (CEM). An automated and portable device, the CEMport, is introduced and implemented using a 2 nm resolution displacement sensor with demonstrated accuracy and precision of 3% and 2%, respectively, of CEM in biogels. Importantly, the small strains (disorders, potentially leading to improved diagnostics and therapeutic monitoring.

  10. Changes to the structure of blood clots formed in the presence of fine particulate matter

    Energy Technology Data Exchange (ETDEWEB)

    Metassan, Sofian; Routledge, Michael N [Molecular Epidemiology Unit, Leeds Institute for Health, Genetics and Therapeutics, LIGHT Laboratories, University of Leeds, Leeds LS2 9JT (United Kingdom); Ariens, Robert A S; Scott, D Julian, E-mail: umphsp@leeds.ac.u [Cardiovascular and Diabetes Research Division, Leeds Institute for Health, Genetics and Therapeutics, The LIGHT Laboratories, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2009-02-01

    Both long-term and short-term exposure (one to two hours) to particulate matter are associated with morbidity and mortality caused by cardiovascular diseases. The underlying mechanisms leading to cardiovascular events are unclear, however, changes to blood coagulability upon exposure to ultrafine particulate matter (UFPM, the smallest of which can enter the circulation) is a plausible mechanism. Objectives: This study aims to investigate the direct effects of particulate matter on fibrin polymerization, lateral aggregation and the formation of fibrin network structure. Methods: Standard Urban Particulate Matter (PM) was suspended in Tris buffer centrifuged and filtered with <200nm filter to obtain ultrafine PM or their water-soluble components. Purified normal fibrinogen was made to clot by adding thrombin and calcium chloride in the presence of varying concentrations of PM. Permeation properties (Darcy constant [Ks]) and turbidity of clots were measured to investigate the effects on flow-rate, pore size, and fibrin polymerization. In addition, confocal microscopy was performed to study detailed clot structure. Results: Total PM increased the Ks of clots in a dose dependant manner (Ks = 4.4, 6.9 and 13.2 x 10-9 cm2 for 0, 50 and 100 |ag/ml total PM concentrations, respectively). Filtered PM also produced a significant increase in Ks at PM concentration of 17 |ag/ml. Final turbidity measurements at 20min were obtained for varying concentrations of PM. Maximum optical density (OD) for 1 mg/ml fibrinogen at 0, 50, 100 and 200 |ag/ml total PM concentrations were 0.39, 0.42, 0.45 and 0.46, respectively. The maximum OD for 0, 17, 34 and 68 |ag/ml filtered PM concentrations were 0.39, 0.42 0.47 and 0.51, respectively, suggesting an increase in fibre diameter with increasing particulate concentration. The lag phase was significantly shorter and the rate of polymerisation was significantly faster in the presence of 68 |ag/ml filtered PM. Confocal microscopy results showed

  11. Effect of anticoagulant administration on blood clotting and some hormones related to rat-fertility

    International Nuclear Information System (INIS)

    This study was performed using 30 mature male albino rats divided into 3 equal groups; control and two treated groups to assess the effect of anticoagulant (warfarin) administration on the level of some hormones related to fertility. The two treated groups were injected intraperitoneally every other day with 1 ml (0.03 mg)and 2 ml (0.06 mg)warfarin/ 100 g body weight respectively where, two specimens were taken from each group after two and four weeks. Clotting time (CT), prothrombin time (PT), partial prothrombin time (PTT) platelets count, fasting blood sugar (F.B.S), calcium levels in addition to triiodothyronine (T3), thyroxin (T4), insulin, corticosterone, and testosterone hormones were determined. The results showed that the intraperitoneal injection of warfarin caused significant increase in clotting time, prothrombin time , partial prothrombin time, platelets count and glucose level, while serum calcium level showed significant decrease. Intraperitoneal injection of warfarin caused significant decrease of insulin and significant increase of corticosterone, T3 showed significant decrease in high dose group while T4 showed significant decrease in small dose group. The high dose was associated with the highest level of testosterone hormone. these results denoted that warfarin anticoagulant had no negative effect on gonadal sex hormone and hence on male fertility

  12. Acute small bowel obstruction due to a large intraluminal blood clot after laparoscopic Roux-en-Y gastric bypass.

    Science.gov (United States)

    Green, Jessica; Ikuine, Tomoko; Hacker, Shoshana; Urrego, Hernan; Tuggle, Karleena

    2016-01-01

    Small bowel obstructions (SBOs) are a known perioperative complication of laparoscopic Roux-en-Y gastric bypass and common etiologies include internal hernia, port site hernia, jejunojejunostomy stricture, ileus and adhesions. Less commonly, SBO can be caused by superior mesenteric artery syndrome, intussusception and intraluminal blood clot. We present a case of SBO caused by intraluminal blood clot from jejunojejunostomy staple line bleeding in a patient with a normal coagulation profile. Computed tomography was used to elucidate the cause of perioperative SBO, and diagnostic laparoscopy was used to both diagnose and treat the complication. In this case, the intraluminal clot was evacuated laparoscopically by enterotomy, thrombectomy and primary closure without anastomotic revision since there was no evidence of continued bleeding. Administration of enoxaparin and Toradol post-operatively may have exacerbated mild intraluminal bleeding occurring at the stapled jejunojejunal anastomosis. Prompt recognition and treatment of perioperative SBO can prevent catastrophic consequences related to bowel perforation. PMID:27554828

  13. Proton NMR study of the state of water in fibrin gels, plasma, and blood clots

    International Nuclear Information System (INIS)

    A proton NMR relaxation and pulsed field gradient self-diffusion study of water in fibrin gels, plasma, and blood clots has been performed with special emphasis on the effect of the sol-gel and shrinkage transitions. Deuteron NMR in fibrin gels was also studied to supplement the proton data. It is shown that a measurement of the water proton or deuteron T1/T2 ratio allows for a determination of the bound water fraction in all these systems. The change in the T1/T2 ratio at the shrinkage transition further allows for a determination of the surface fractal dimension of the gel if the change in the volume of the gel is known. The self-diffusion coefficient of water in these systems, which determines the transport properties of the gel, is found to be proportional to the free water fraction in both the nonshrunken and shrunken state

  14. Abolished ventilation and perfusion of lung caused by blood clot in the left main bronchus

    DEFF Research Database (Denmark)

    Afzelius, P; Bergmann, A; Henriksen, J H

    2015-01-01

    It is generally assumed that the lungs possess arterial autoregulation associated with bronchial obstruction. A patient with pneumonia and congestive heart failure unexpectedly developed frequent haemoptysis. High-resolution CT and diagnostic CT were performed as well as ventilation/perfusion (V....../Q) scintigraphy with single-photon emission CT (SPECT)/CT. V/Q SPECT/CT demonstrated abolished ventilation due to obstruction of the left main bronchus and markedly reduced perfusion of the entire left lung, a condition that was completely reversed after removal of a blood clot. We present the first pictorially...... documented case of hypoxia-induced pulmonary vasoconstriction and flow shift in a main pulmonary artery due to a complete intrinsic obstruction of the ipsilateral main bronchus. The condition is reversible, contingent on being relieved within a few days....

  15. Highly Effective DNA Extraction Method from Fresh, Frozen, Dried and Clotted Blood Samples

    Directory of Open Access Journals (Sweden)

    Jaleh Barar

    2011-09-01

    Full Text Available Introduction: Today, with the tremendous potential of genomics and other recent advances in science, the role of science to improve reliable DNA extraction methods is more relevant than ever before. The ideal process for genomic DNA extraction demands high quantities of pure, integral and intact genomic DNA (gDNA from the sample with minimal co-extraction of inhibitors of downstream processes. Here, we report the development of a very rapid, less-hazardous, and high throughput protocol for extracting of high quality DNA from blood samples. Methods: Dried, clotted and ethylene diamine tetra-acetic acid (EDTA treated fresh and frozen blood samples were extracted using this method in which the quality and integrity of the extracted DNA were corroborated by agarose gel electrophoresis, PCR reaction and DNA digestion using restricted enzyme. The UV spectrophotometric and gel electrophoresis analysis resulted in high A260/A280 ratio (>1.8 with high intactness of DNA. Results: PCR and DNA digestion experiments indicated that the final solutions of extracted DNA contained no inhibitory substances, which confirms that the isolated DNA is of good quality. Conclusion: The high quality and quantity of current method, no enzymatic processing and accordingly its low cost, make it appropriate for DNA extraction not only from human but also from animal blood samples in any molecular biology labs.

  16. Cloning, expression and characterization of a gene from earthworm Eisenia fetida encoding a blood-clot dissolving protein.

    Science.gov (United States)

    Li, GangQiang; Wang, Kevin Yueju; Li, DaHui; Wang, Nan; Liu, DeHu

    2012-01-01

    A lumbrokinase gene encoding a blood-clot dissolving protein was cloned from earthworm (Eisenia fetida) by RT-PCR amplification. The gene designated as CST1 (GenBank No. AY840996) was sequence analyzed. The cDNA consists of 888 bp with an open reading frame of 729 bp, which encodes 242 amino acid residues. Multiple sequence alignments revealed that CST1 shares similarities and conserved amino acids with other reported lumbrokinases. The amino acid sequence of CST1 exhibits structural features similar to those found in other serine proteases, including human tissue-type (tPA), urokinase (uPA), and vampire bat (DSPAα1) plasminogen activators. CST1 has a conserved catalytic triad, found in the active sites of protease enzymes, which are important residues involved in polypeptide catalysis. CST1 was expressed as inclusion bodies in Escherichia coli BL21(DE3). The molecular mass of recombinant CST1 (rCST) was 25 kDa as estimated by SDS-PAGE, and further confirmed by Western Blot analysis. His-tagged rCST1 was purified and renatured using nickel-chelating resin with a recovery rate of 50% and a purity of 95%. The purified, renatured rCST1 showed fibrinolytic activity evaluated by both a fibrin plate and a blood clot lysis assay. rCST1 degraded fibrin on the fibrin plate. A significant percentage (65.7%) of blood clot lysis was observed when blood clot was treated with 80 mg/mL of rCST1 in vitro. The antithrombotic activity of rCST1 was 912 units/mg calculated by comparison with the activity of a lumbrokinase standard. These findings indicate that rCST1 has potential as a potent blood-clot treatment. Therefore, the expression and purification of a single lumbrokinase represents an important improvement in the use of lumbrokinases. PMID:23300872

  17. Cerebral blood flow velocities after subarachnoid haemorrhage in relation to the amount of blood clots in the initial computed tomography

    International Nuclear Information System (INIS)

    In 72 patients with acute subarachnoid haemorrhage (SAH) the relationship between the amount of subarachnoid blood clots detected by initial cranial computed tomography (CCT) up to 48 hours after bleeding and the later development of vasospasm, established by blood flow velocity measurement with transcranial Doppler ultrasound (TCD) was investigated. The serial Doppler examinations started within the first 72 hours after SAH and were carried out every second day up to three weeks. Each Doppler recording was accompanied by a neurological examination. Patients classified as Hunt and Hess grade V were excluded from the study. All patients with remarkable brain oedema in CCT or with intracranial pressure above 25 mmHg were also excluded. Because of the well known agedependence of vasospasm after SAH, two age groups were formed. A statistically significant correlation (p > 0.05) between blood flow velocities and blood load after SAH was not found. The mean age of the investigated 72 individuals was 48.9 years (14 up to 76 years). 47 patients were younger than 56 years. Linear regression analysis indicated a correlation with a quite low significance level (r = 0.350, p 0.05) between these two variables could be established in the 25 patients older than 55 years. In a second step an intra-individual comparison of side-to-side differences in TCD and CCT was made. There were no significant differences in blood flow velocities between subjects with or without side-to-side differences in cisternal blood load. It is concluded that the amount of blood visible on initial CCT after SAH is not a powerful predictor of cerebral blood flow velocities measured by TCD. (author)

  18. Rosuvastatin Reduced Blood Clot Risk%罗苏伐他汀可减少血栓形成

    Institute of Scientific and Technical Information of China (English)

    吴河水; 洪班信

    2009-01-01

    A large trial of the cholesterol lowering drug rosuvastatin showed that giving1 it to healthy adults reduced their risk of blood clots (venous thromboembolism) by 43 per cent. This was the result of a subgroup analysis in the JUPITER trial2, and was published online on 28 March in The Lancet and presented at the American College of Cardiology's 58th Annual Scientific Sessions.

  19. Anti-thrombogenic properties of a nitric oxide-releasing dextran derivative: evaluation of platelet activation and whole blood clotting kinetics

    Science.gov (United States)

    Damodaran, Vinod B.; Leszczak, Victoria; Wold, Kathryn A.; Lantvit, Sarah M.; Popat, Ketul C.; Reynolds, Melissa M.

    2013-01-01

    Controlling platelet activation and clotting initiated by cardiovascular interventions remains a major challenge in clinical practice. In this work, the anti-thrombotic properties of a polysaccharide-based nitric oxide (NO)-releasing dextran derivative are presented. Total platelet adhesion, platelet morphology and whole blood clotting kinetics were used as indicators to evaluate the anti-clotting properties of this material. With a total NO delivery of 0.203±0.003 μmol, the NO-releasing dextran derivative (Dex-SNO) mixed with blood plasma demonstrated a significantly lower amount of platelet adhesion and activation onto a surface and reduced whole blood clotting kinetics. Nearly 75% reduction in platelet adhesion and a significant retention of platelet morphology were observed with blood plasma treated with Dex-SNO, suggesting this to be a potential anti-platelet therapeutic agent for preventing thrombosis that does not have an adverse effect on circulating platelets. PMID:24349705

  20. Does prior administration of enoxaparin influence the effects of levobupivacaine on blood clotting? Assessment using the Thrombelastograph.

    LENUS (Irish Health Repository)

    Leonard, S A

    2012-02-03

    The low molecular weight heparin, enoxaparin (by inhibition of factors Xa and IIa) and amide local anaesthetics (by altering platelet function) exert anti-clotting effects. Although these agents are often used in combination during the perioperative period, their potential interactive effect on clotting has not been defined. Blood from 10 ASA I-II patients who received enoxaparin 0.5 mg kg(-1) s.c. was studied using a Thrombelastograph (TEG) either alone or in combination with levobupivacaine (2.5 mg ml(-1) or 2.5 microg ml(-1)) or saline (50% dilution). In blood from patients who had received enoxaparin 0.5 mg kg(-1) s.c. 12 h previously, levobupivacaine 2.5 mg ml(-1) (but not 2.5 microg ml(-1)) produced significant changes in TEG clotting parameters (mean (SD) 15.7 (4.8) mm, 29.6 (25.6) mm, 34.4 (14.6) mm, 34.3 (12.2) degrees compared with control values of 6.1 (1.3) mm, 2.5 (0.5) mm, 63.5 (6.4) mm and 74.1 (2.9) degrees for r, K, MA, and alpha angle respectively).

  1. Deep Vein Thrombosis (DVT) / Pulmonary Embolism (PE) - Blood Clot Forming in a Vein

    Science.gov (United States)

    ... located in a central vein Inherited clotting disorders Preventing DVT The following tips can help prevent DVT: Move around as soon as possible after having been confined to bed, such as after surgery, illness, or injury. If you’re at risk ...

  2. Fibrinolytic Activity and Dose-Dependent Effect of Incubating Human Blood Clots in Caffeic Acid Phenethyl Ester: In Vitro Assays

    Directory of Open Access Journals (Sweden)

    Abuzar Elnager

    2015-01-01

    Full Text Available Background. Caffeic acid phenethyl ester (CAPE has been reported to possess time-dependent fibrinolytic activity by in vitro assay. This study is aimed at investigating fibrinolytic dose-dependent activity of CAPE using in vitro assays. Methods. Standardized human whole blood (WB clots were incubated in either blank controls or different concentrations of CAPE (3.75, 7.50, 15.00, 22.50, and 30.00 mM. After 3 hours, D-dimer (DD levels and WB clot weights were measured for each concentration. Thromboelastography (TEG parameters were recorded following CAPE incubation, and fibrin morphology was examined under a confocal microscope. Results. Overall, mean DD (μg/mL levels were significantly different across samples incubated with different CAPE concentrations, and the median pre- and postincubation WB clot weights (grams were significantly decreased for each CAPE concentration. Fibrin removal was observed microscopically and indicated dose-dependent effects. Based on the TEG test, the Ly30 fibrinolytic parameter was significantly different between samples incubated with two different CAPE concentrations (15.0 and 22.50 mM. The 50% effective dose (ED50 of CAPE (based on DD was 1.99 mg/mL. Conclusions. This study suggests that CAPE possesses fibrinolytic activity following in vitro incubation and that it has dose-dependent activities. Therefore, further investigation into CAPE as a potential alternative thrombolytic agent should be conducted.

  3. Fatal dynamic hyperinflation secondary to a blood clot acting as a one-way valve at the internal orifice of a tracheostomy tube

    OpenAIRE

    Raschke RA

    2012-01-01

    We report the case of a patient who suffered fatal cardiopulmonary effects of a mobile blood clot adherent to the internal orifice of her tracheostomy tube. We believe the clot acted as a one-way valve, leading to dynamic hyperinflation and elevated intrinsic positive end expiratory pressure (iPEEP). This complication of a tracheostomy tube was suggested by clinical findings of expiratory wheezing, hypotension, increasing peak inspiratory pressure, and unusual but distinctive radiographic fin...

  4. Design and Testing of a Minimally Invasive Blood Clot Removal Device ConstructedWith Elements of Superelastic Nitinol

    Science.gov (United States)

    Puffer, Andrew J.

    Many vascular system problems stem from insufficient blood return flow to the heart. One of the main causes is a blockage within veins or arteries known as a blood clot, or thrombus. This can occur after trauma, surgery, or other phenomenological reasons. Each year in the U.S. more than 175,000 bypass procedures and more than 160,000 amputations resulting from peripheral vessel disease are performed. Clinical data indicates that clot removal devices and procedures can reduce the need for an amputation by 80 percent. Percutaneous thrombectomy refers to the removal of thrombus using catheter based non-surgical methods. The ultimate goal of any modality to treat these conditions of the arterial or venous system is to restore patency, quickly, safely, and cost effectively. Catheter directed thrombectomy and thrombolysis is less traumatic and avoids the morbidity and mortality associated with conventional surgical technique. As a result, there has been a push recently for the use of percutaneous mechanical thrombectomy (PMT) devices. However, all devices have their own set of drawbacks: distal embolization, vessel wall trauma, hemolysis, to name a few. Ongoing efforts have been made to create a prototype thrombectomy device that uses elements of superelastic nitinol (a type of shape memory alloy), that seeks to address some of the drawbacks of current devices. The prototype was designed and tested in a simulated human circulatory system along side a commercially available device (The DiverCE Clot Extraction Catheter). The test evaluated how well the devices minimized distal embolization of a human blood clot created in vitro.. Results of the testing showed that the prototype device created significantly less embolization when compared to the DiverCE particles greater than 102mum (p = 0.0332). Means were statistically not different for particles between 25mum and 102mum (p = 0.2454), and particles between 5mum and 25mum (p = 0.6524). In addition the prototype was shown

  5. In vitro clot lysis as a potential indicator of thrombus resistance to fibrinolysis--study in healthy subjects and correlation with blood fibrinolytic parameters.

    Science.gov (United States)

    Colucci, M; Scopece, S; Gelato, A V; Dimonte, D; Semeraro, N

    1997-04-01

    Using an in vitro model of clot lysis, the individual response to a pharmacological concentration of recombinant tissue plasminogen activator (rt-PA) and the influence on this response of the physiological variations of blood parameters known to interfere with the fibrinolytic/thrombolytic process were investigated in 103 healthy donors. 125I-fibrin labelled blood clots were submersed in autologous plasma, supplemented with 500 ng/ml of rt-PA or solvent, and the degree of lysis was determined after 3 h of incubation at 37 degrees C. Baseline plasma levels of t-PA, plasminogen activator inhibitor 1 (PAI-1), plasminogen, alpha 2-antiplasmin, fibrinogen, lipoprotein (a), thrombomodulin and von Willebrand factor as well as platelet and leukocyte count and clot retraction were also determined in each donor. rt-PA-induced clot lysis varied over a wide range (28-75%) and was significantly related to endogenous t-PA, PAI-1, plasminogen (p < 0.001) and age (p < 0.01). Multivariate analysis indicated that both PAI-1 antigen and plasminogen independently predicted low response to rt-PA. Surprisingly, however, not only PAI-1 but also plasminogen was negatively correlated with rt-PA-induced clot lysis. The observation that neutralization of PAI-1 by specific antibodies, both in plasma and within the clot, did not potentiate clot lysis indicates that the inhibitor, including the platelet-derived form, is insufficient to attenuate the thrombolytic activity of a pharmacological concentration of rt-PA and that its elevation, similarly to the elevation of plasminogen, is not the cause of clot resistance but rather a coincident finding. It is concluded that the in vitro response of blood clots to rt-PA is poorly influenced by the physiological variations of the examined parameters and that factors other than those evaluated in this study interfere with clot dissolution by rt-PA. In vitro clot lysis test might help to identify patients who may be resistant to thrombolytic therapy

  6. Momordica charantia seed extract exhibits strong anticoagulant effect by specifically interfering in intrinsic pathway of blood coagulation and dissolves fibrin clot.

    Science.gov (United States)

    Manjappa, Bhagyalakshmi; Gangaraju, Sowmyashree; Girish, Kesturu S; Kemparaju, Kempaiah; Gonchigar, Sathish J; Shankar, Rohit L; Shinde, Manohar; Sannaningaiah, Devaraja

    2015-03-01

    The current study explores the anticoagulant and fibrin clot-hydrolyzing properties of Momordica charantia seed extract (MCSE). MCSE hydrolyzed casein with the specific activity of 0.780 units/mg per min. Interestingly, it enhanced the clot formation process of citrated human plasma from control 146 to 432 s. In addition, the intravenous injection of MCSE significantly prolonged the bleeding time in a dose-dependent manner from control 150 to more than 800 s, and strengthened its anticoagulant activity. Interestingly, MCSE specifically prolonged the clotting time of only activated partial thromboplastin time, but not prothrombin time, and revealed the participation of MCSE in the intrinsic pathway of the blood coagulation cascade. Furthermore, MCSE completely hydrolyzed both Aα and Bβ chains of the human fibrinogen and partially hydrolyzed the γ chain. However, it hydrolyzed all the chains (α polymer, α chain, β chain and γ-γ dimmers) of partially cross-linked human fibrin clot. The proteolytic activity followed by the anticoagulant effect of the MCSE was completely abolished by the 1,10-phenanthroline and phenyl methyl sulphonyl fluoride, but iodoacetic acid, EDTA, and ethylene glycol-N,N,N',N'-tetra acetic acid did not. Curiously, MCSE did not hydrolyze any other plasma proteins except the plasma fibrinogen. Moreover, MCSE was devoid of RBC lysis, edema and hemorrhagic properties, suggesting its nontoxic nature. Taken together, MCSE may be a valuable candidate in the treatment of blood clot/thrombotic disorders. PMID:25192240

  7. Vibrations and spatial patterns in biomimetic surfaces: using the shark-skin effect to control blood clotting.

    Science.gov (United States)

    Ramachandran, Rahul; Maani, Nazanin; Rayz, Vitaliy L; Nosonovsky, Michael

    2016-08-01

    We study the effect of small-amplitude fast vibrations and small-amplitude spatial patterns on various systems involving wetting and liquid flow, such as superhydrophobic surfaces, membranes and flow pipes. First, we introduce a mathematical method of averaging the effect of small spatial and temporal patterns and substituting them with an effective force. Such an effective force can change the equilibrium state of a system as well as a phase state, leading to surface texture-induced and vibration-induced phase control. Vibration and patterns can effectively jam holes in vessels with liquid, separate multi-phase flow, change membrane properties, result in propulsion and locomotion and lead to many other multi-scale, nonlinear effects including the shark-skin effect. We discuss the application of such effects to blood flow for novel biomedical 'haemophobic' applications which can prevent blood clotting and thrombosis by controlling the surface pattern at a wall of a vessel (e.g. a catheter or stent).This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. PMID:27354733

  8. Effect of whole-body irradiation on the level of blood clotting factors in rats

    International Nuclear Information System (INIS)

    Rats were irradiated with 6.0, 7.0 or 9.5 Gy of X-rays. Blood was collected on the 1,3,7,14 or 30th day after exposure. Fibrinogen, thrombin, prothrombin, factor X and antithrombin 3 levels were determined in blood plasma. In irradiated rats the level of these factors underwent a change which depended to some extent on the radiation dose absorbed. In general, there was a temporary elevation of all factors, lasting longer when the dose applied was higher. 24 refs., 6 tabs. (author)

  9. Factors affecting the lung perfused blood volume in patients with intrapulmonary clots after anti-coagulation therapy

    International Nuclear Information System (INIS)

    Highlights: • Dual-energy CT can provide morphological and functional lung images in the same examination. • The subsequent dual-energy CT demonstrates the increased whole lung perfused blood volume (V120) despite the residual intrapulmonary clots after treatment in one examination. • The increased whole lung perfusion (V120) and a decreased low perfusion volume (V5) result in the improvement in the low perfusion rate (%V5) in the patients with acute pulmonary embolism after treatment. - Abstract: Objectives: Factors affecting the improvement in the lung perfused blood volume (LPBV) were evaluated based on the presence of intrapulmonary clots (IPCs) after anti-coagulation therapy using 64-slice dual-energy CT. Materials and methods: 96 patients exhibiting venous thromboembolism underwent initial and repeated LPBV examinations between December 2008 and July 2014. Fifteen patients were excluded due to pulmonary comorbidities, and a total of 81 patients were included in this study. Acute pulmonary embolism (PE) was diagnosed in 46 of the patients (56.7%). LPBV images were three-dimensionally reconstructed with two threshold ranges: 1–120 HU (V120) and 1–5 HU (V5), and the relative value of V5 per V120 expressed as %V5. These values were subsequently compared with indicators of the severity of PE, such as the D-dimer level, heart rate and CT measurements. This study was approved by the local ethics committee. Results: In patients with IPCs, the D-dimer, V5 and %V5values were significantly larger (p ≤ 0.01) in the initial LPBV, although these differences disappeared in subsequent LPBV after treatment. The right ventricular (RV) diameter, RV/left ventricular (RV/LV) diameter ratio and %V5 values were also significantly reduced, whereas the V5 value did not significantly decrease (p = 0.07), but V120 value significantly increased (p < 0.001) after treatment. However, in patients with IPCs the change rate in %V5 [(subsequent-initial)/initial %V5] showed a

  10. Factors affecting the lung perfused blood volume in patients with intrapulmonary clots after anti-coagulation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Munemasa, E-mail: radokada@yamaguchi-u.ac.jp [Department of Radiology, Yamaguchi University Graduate School of Medicine 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Masuda, Yu [4th Grade of 6-year Medicine Doctor Program, Department of Medicine, Yamaguchi University Faculty of Medicine and Health Sciences 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Nakashima, Yoshiteru [Department of Radiology, Yamaguchi Grand Medical Center, Oosaki 77, Hofu, Yamaguchi 747-8511 (Japan); Nomura, Takafumi; Nakao, Sei [Department of Radiology, Yamaguchi University Graduate School of Medicine 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Suga, Kazuyoshi [Department of Radiology, St Hills Hospital, Imamurakita 3-7-18, Ube, Yamaguchi 755-0155 (Japan); Kido, Shoji [Computer-aided Diagnosis and Biomedical Imaging Research Biomedical Engineering, Applied Medical Engineering Science Graduate School of Medicine, Yamaguchi University, Tokiwadai 2-16-1, Ube, Yamaguchi 755-8611 (Japan); Matsunaga, Naofumi [Department of Radiology, Yamaguchi University Graduate School of Medicine 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan)

    2015-08-15

    Highlights: • Dual-energy CT can provide morphological and functional lung images in the same examination. • The subsequent dual-energy CT demonstrates the increased whole lung perfused blood volume (V{sub 120}) despite the residual intrapulmonary clots after treatment in one examination. • The increased whole lung perfusion (V{sub 120}) and a decreased low perfusion volume (V{sub 5}) result in the improvement in the low perfusion rate (%V{sub 5}) in the patients with acute pulmonary embolism after treatment. - Abstract: Objectives: Factors affecting the improvement in the lung perfused blood volume (LPBV) were evaluated based on the presence of intrapulmonary clots (IPCs) after anti-coagulation therapy using 64-slice dual-energy CT. Materials and methods: 96 patients exhibiting venous thromboembolism underwent initial and repeated LPBV examinations between December 2008 and July 2014. Fifteen patients were excluded due to pulmonary comorbidities, and a total of 81 patients were included in this study. Acute pulmonary embolism (PE) was diagnosed in 46 of the patients (56.7%). LPBV images were three-dimensionally reconstructed with two threshold ranges: 1–120 HU (V{sub 120}) and 1–5 HU (V{sub 5}), and the relative value of V{sub 5} per V{sub 120} expressed as %V{sub 5}. These values were subsequently compared with indicators of the severity of PE, such as the D-dimer level, heart rate and CT measurements. This study was approved by the local ethics committee. Results: In patients with IPCs, the D-dimer, V{sub 5} and %V{sub 5}values were significantly larger (p ≤ 0.01) in the initial LPBV, although these differences disappeared in subsequent LPBV after treatment. The right ventricular (RV) diameter, RV/left ventricular (RV/LV) diameter ratio and %V{sub 5} values were also significantly reduced, whereas the V{sub 5} value did not significantly decrease (p = 0.07), but V{sub 120} value significantly increased (p < 0.001) after treatment. However, in

  11. Abolished ventilation and perfusion of lung caused by blood clot in the left main bronchus: auto-downregulation of pulmonary arterial blood supply.

    Science.gov (United States)

    Afzelius, P; Bergmann, A; Henriksen, J H

    2015-01-01

    It is generally assumed that the lungs possess arterial autoregulation associated with bronchial obstruction. A patient with pneumonia and congestive heart failure unexpectedly developed frequent haemoptysis. High-resolution CT and diagnostic CT were performed as well as ventilation/perfusion (V/Q) scintigraphy with single-photon emission CT (SPECT)/CT. V/Q SPECT/CT demonstrated abolished ventilation due to obstruction of the left main bronchus and markedly reduced perfusion of the entire left lung, a condition that was completely reversed after removal of a blood clot. We present the first pictorially documented case of hypoxia-induced pulmonary vasoconstriction and flow shift in a main pulmonary artery due to a complete intrinsic obstruction of the ipsilateral main bronchus. The condition is reversible, contingent on being relieved within a few days. PMID:26374773

  12. A comparative evaluation of the blood clot, platelet-rich plasma, and platelet-rich fibrin in regeneration of necrotic immature permanent teeth: A clinical study

    Directory of Open Access Journals (Sweden)

    Isha Narang

    2015-01-01

    Full Text Available Introduction: This study was designed as a clinical trial to evaluate and compare the regenerative potential of platelet-rich fibrin (PRF, platelet-rich plasma (PRP, and blood clot in immature necrotic permanent teeth with or without associated apical periodontitis. Methods: Access preparation was done under rubber dam isolation. Copious irrigation was done with 2.5% NaOCl and triple antibiotic paste was placed as an intracanal medicament. After 4 weeks, the cases were divided into four groups with five patients in each group. The study design had three test arms and one control arm. Group I in which mineral trioxide aggregate apexification was carried out and it was kept as control group to evaluate the regenerative potential of blood clot and platelet concentrates, Group II in which blood clot was used as scaffold in the canal, Group III in PRF was used as scaffold, and Group IV in which PRP carried on collagen was used as a scaffold. Results: The clinical and radiographic evaluation after 6 and 18 months was done by two independent observers who were blinded from the groups. The scoring was done as: None score was denoted by, Fair by 1, Good by 2, and Excellent by 3. The data were then analyzed statistically by Fisher′s exact test using Statistics and Data 11.1(PRP Using harvest Smart PReP2 which showed statistically significant values in Group III as compared to other Groups. Conclusion: PRF has huge potential to accelerate the growth characteristics in immature necrotic permanent teeth as compared to PRP and blood clot.

  13. Blood Clotting and Pregnancy

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  1. Blood Clotting and Pregnancy

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    Full Text Available ... your understanding of lymphoma pathogenesis ASH Workshop on Genome Editing July 14-15, 2016 Learn new techniques in the clinical application of genome editing technology ASH Meeting on Hematologic Malignancies September ...

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  6. Blood Clotting and Pregnancy

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  17. Hypomethylation of serum blood clot DNA, but not plasma EDTA-blood cell pellet DNA, from vitamin B12-deficient subjects.

    Directory of Open Access Journals (Sweden)

    Eoin P Quinlivan

    Full Text Available Vitamin B12, a co-factor in methyl-group transfer, is important in maintaining DNA (deoxycytidine methylation. Using two independent assays we examined the effect of vitamin B12-deficiency (plasma vitamin B12<148 pmol/L on DNA methylation in women of childbearing age. Coagulated blood clot DNA from vitamin B12-deficient women had significantly (p<0.001 lower percentage deoxycytidine methylation (3.23±0.66%; n = 248 and greater [3 H]methyl-acceptance (42,859±9,699 cpm; n = 17 than DNA from B12-replete women (4.44±0.18%; n = 128 and 26,049±2,814 cpm; n = 11 [correlation between assays: r = -0.8538; p<0.001; n = 28]. In contrast, uncoagulated EDTA-blood cell pellet DNA from vitamin B12-deficient and B12-replete women exhibited similar percentage methylation (4.45±0.15%; n = 77 vs. 4.47±0.15%; n = 47 and [3 H]methyl-acceptance (27,378±4,094 cpm; n = 17 vs. 26,610±2,292 cpm; n = 11. Therefore, in simultaneously collected paired blood samples, vitamin B12-deficiency was associated with decreased DNA methylation only in coagulated samples. These findings highlight the importance of sample collection methods in epigenetic studies, and the potential impact biological processes can have on DNA methylation during collection.

  18. The development of a blood clotting response test for discriminating between difenacoum-resistant and susceptible Norway rats (Rattus norvegicus, Berk.).

    Science.gov (United States)

    Gill, J E; Kerins, G M; Langton, S D; MacNicoll, A D

    1993-01-01

    1. A new test for identifying levels of difenacoum resistance in the Norway rat is described, based upon the differential physiological response to difenacoum administration. 2. This test is based on changes in blood clotting activity over 4 days, following administration of the rodenticide difenacoum in conjunction with menadione (vitamin K3). 3. The anticoagulant effect is reduced only in rats that are resistant or tolerant to difenacoum. 4. This test procedure is quicker than traditional feeding tests, and identifies the degree of resistance in both laboratory and wild rats that have difenacoum resistance genes. PMID:8097452

  19. Synthesis, purification, and characterization of an Arg152 → Glu site-directed mutant of recombinant human blood clotting factor VII

    International Nuclear Information System (INIS)

    Coagulation factor VII circulates in blood as a single-chain zymogen of a serine protease and is converted to its activated two-chain form, factor VIIa, by cleavage of an internal peptide bond located at Arg152-Ile153. Previous studies using serine protease active-site inhibitors suggest that zymogen factor VII may possess sufficient proteolytic activity to initiate the extrinsic pathway of blood coagulation. In order to assess the putative intrinsic proteolytic activity of single-chain factor VII, the authors have constructed a site-specific mutant of recombinant human factor VII in which arginine-152 has been replaced with a glutamic acid residue. Mutant factor VII was purified in a single step from culture supernatants of baby hamster kidney cells transfected with a plasmid containing the sequence for Arg152 → Glu factor VII using a calcium-dependent, murine anti-factor VII monoclonal antibody column. The clotting activity of mutant factor VII was completely inhibited following incubation with dansyl-Glu-Gly-Arg chloromethyl ketone, suggesting that the apparent clotting activity of mutant factor VII was due to a contaminating serine protease. Immunoblots of mutant factor VII with human factor IXa revealed no cleavage, whereas incubation of mutant factor VII with human factor Xa resulted in cleavage of mutant factor VII and the formation of a lower molecular weight degradation product migrating at Mr∼40 000. The results are consistent with the proposal that zymogen factor VII possesses no intrinsic proteolytic activity toward factor X or factor IX

  20. In Vivo Quantification of Clot Formation in Extracorporeal Circuits

    CERN Document Server

    David, Omid

    2012-01-01

    Clot formation is a common complication in extracorporeal circuits. In this paper we describe a novel method for clot formation analysis using image processing. We assembled a closed extracorporeal circuit and circulated blood at varying speeds. Blood filters were placed in downstream of the flow, and clotting agents were added to the circuit. Digital images of the filter were subsequently taken, and image analysis was applied to calculate the density of the clot. Our results show a significant correlation between the cumulative size of the clots, the density measure of the clot based on image analysis, and flow duration in the system.

  1. Tranexamic acid combined with recombinant factor VIII increases clot resistance to accelerated fibrinolysis in severe hemophilia A

    DEFF Research Database (Denmark)

    Hvas, Anne-Mette; Sørensen, Hanne Thykjær; Norengaard, Lisbeth;

    2007-01-01

    BACKGROUND: Most patients with severe hemophilia A suffer from a profoundly compromised hemostatic response. In addition to both the delayed and slow development of a clot, previous studies have documented that severe hemophilia A is also associated with reduced clot stability. OBJECTIVES: We...... activation. Clot formation was assessed by both clot initiation and clot propagation. At clot termination, the maximum clot firmness and area under the elasticity curve were used to illustrate clot stability. Tissue-plasminogen activator was included in those experiments designed to assess clot stability....... RESULTS: As expected, rFVIII increased clot formation, whereas TXA had no effect upon this parameter. Assays including tissue-plasminogen activator revealed that rFVIII increased the maximum clot firmness 3-fold; whereas the presence of TXA induced an additional 4-fold increase. The area under the...

  2. Investigation of the effect of kaolin and tissue factor-activated citrated whole blood, on clot forming variables, as evaluated by thromboelastograph

    DEFF Research Database (Denmark)

    Johansson, Per Ingemar; Bochsen, L.; Andersen, S.;

    2008-01-01

    laboratory-based analysis, however, requires validation of the activators employed and the effect of storage of the WB sample in citrate before analysis. STUDY DESIGN AND METHODS: The effect of kaolin, tissue factor (TF) 1:17,000, or TF 1:42,500 on TEG clotting time (R), Angle (velocity of clot formation......), and maximum clot strength (amplitude [MA]) were evaluated, together with day-to-day variation, the coefficient of variance (CV%), and the effect of citrate storage time. RESULTS: Clot formation variables were equally affected by TF 1:17,000 and kaolin activation, whereas R was significantly longer...... rested for 0 and 30 minutes were evaluated with kaolin as the activator. CONCLUSION: The TEG assays evaluated were reproducible and present with an acceptable CV% for routine clinical practice. Kaolin and TF 1:17,000 equally affected the clot formation variables. Storage of WB for up to 30 minutes in...

  3. Fibronectin adsorption on surface-modified polyetherurethanes and their differentiated effect on specific blood elements related to inflammatory and clotting processes.

    Science.gov (United States)

    Hugoni, Ludivine; Montaño-Machado, Vanessa; Yang, Meilin; Pauthe, Emmanuel; Mantovani, Diego; Santerre, J Paul

    2016-01-01

    After the introduction of a medical device into the body, adhesive proteins such as fibronectin (Fn) will adsorb to the surface of the biomaterial. Monocytes (MCs) will interact with these adsorbed proteins, and adopt either a proinflammatory and/or prowound healing phenotype, thereby influencing many blood interaction events including thrombogenesis. In this work, Fn adsorption as well as subsequent MC response and thrombus formation were investigated on two surfaces-modified polyetherurethanes (PEUs) using different surface modifiers: an anionic/dihydroxyl oligomeric (ADO) additive, known to enable cell adhesion, and a fluorinated polypropylene oxide oligomer (PPO), known to reduce platelet adhesion. Results indicated that at 24 h of MC culture, PEU-ADO and PEU-PPO promoted an anti-inflammatory character relative to the base PEU. Longer clotting times, based on a free hemoglobin assay, were also found on the two surface-modified PEUs relative to the native one, suggesting their potential for the reduction of thrombus formation. In presence of a Fn monolayer, the surface-modified PEUs conserved a lower thrombogenic character than the base PEU, and was however significantly decreased when compared to prior protein adsorption. Furthermore, Fn coatings increased the MC production levels of tumor necrosis factor-α and interleukin-10 at 24 h, while not affecting the anti-inflammatory effect of the modifications relative to the base PEU. This finding was most prominent on PEU-PPO, suggesting that the interaction of the adsorbed Fn with blood cells was different for the two additives. Hence, the results highlighted differentiating effects of Fn adsorption on specific blood activating processes related to inflammatory and thrombotic responses. PMID:27246517

  4. Comparison of Topical Hemostatic Agents in a Swine Model of Extremity Arterial Hemorrhage: BloodSTOP iX Battle Matrix vs. QuikClot Combat Gauze

    Science.gov (United States)

    Li, Huixi; Wang, Lin; Alwaal, Amjad; Lee, Yung-Chin; Reed-Maldonado, Amanda; Spangler, Taylor A.; Banie, Lia; O’Hara, Reginald B.; Lin, Guiting

    2016-01-01

    BloodSTOP iX Battle Matrix (BM) and QuikClot Combat Gauze (CG) have both been used to treat traumatic bleeding. The purpose of this study was to examine the efficacy and initial safety of both products in a swine extremity arterial hemorrhage model, which mimics combat injury. Swine (37.13 ± 0.56 kg, NBM = 11, NCG = 9) were anesthetized and splenectomized. We then isolated the femoral arteries and performed a 6 mm arteriotomy. After 45 s of free bleeding, either BM or CG was applied. Fluid resuscitation was provided to maintain a mean arterial pressure of 65 mmHg. Animals were observed for three hours or until death. Fluoroscopic angiography and wound stability challenge tests were performed on survivors. Tissue samples were collected for histologic examination. Stable hemostasis was achieved in 11/11 BM and 5/9 CG subjects, with recovery of mean arterial pressure and animal survival for three hours (p Histologic evidence indicated no wound site, distal limb or major organ damage in either group. BM is more effective and portable in treating arterial hemorrhage compared to CG. There was no histologic evidence of further damage in either group. PMID:27077848

  5. Differential clot stabilising effects of rFVIIa and rFXIII-A2 in whole blood from thrombocytopenic patients and healthy volunteers

    DEFF Research Database (Denmark)

    Johansson, Per Ingemar; Jacobsen, Niels; Viuff, D.; Olsen, E.H.; Rojkjaer, R.; Andersen, S.; Petersen, Claus Leth; Kjalke, M.

    2008-01-01

    The haemostatic effect of recombinant activated factor VII (rFVIIa;NovoSeven) in thrombocytopenic patients has been a matter of controversy. Haemostasis by rFVIIa occurs via FVIIa-mediated thrombin generation in a platelet-dependent manner and may therefore be suboptimal in patients without....../ml). rFVIIa only modestly improved anti-fibrinolysis,whereas rFXIII-A2 (0-20 microg/ml) enhanced anti-fibrinolysis without effect on clotting time. TEG analysis showed rFVIIa shortened the clotting time, and enhanced clot development, maximal mechanical strength and resistance to fibrinolysis, whereas, r...

  6. Preventing and Treating Blood Clots

    Science.gov (United States)

    ... Health Disparities and Cancer For Patient Advocates Public Policy Advocacy Cancer Awareness Dates Survivorship Blog About Us You ... Health Disparities and Cancer For Patient Advocates Public Policy Advocacy Cancer Awareness Dates Cancer.Net provides timely, comprehensive, ...

  7. Comparison of Topical Hemostatic Agents in a Swine Model of Extremity Arterial Hemorrhage: BloodSTOP iX Battle Matrix vs. QuikClot Combat Gauze

    Directory of Open Access Journals (Sweden)

    Huixi Li

    2016-04-01

    Full Text Available BloodSTOP iX Battle Matrix (BM and QuikClot Combat Gauze (CG have both been used to treat traumatic bleeding. The purpose of this study was to examine the efficacy and initial safety of both products in a swine extremity arterial hemorrhage model, which mimics combat injury. Swine (37.13 ± 0.56 kg, NBM = 11, NCG = 9 were anesthetized and splenectomized. We then isolated the femoral arteries and performed a 6 mm arteriotomy. After 45 s of free bleeding, either BM or CG was applied. Fluid resuscitation was provided to maintain a mean arterial pressure of 65 mmHg. Animals were observed for three hours or until death. Fluoroscopic angiography and wound stability challenge tests were performed on survivors. Tissue samples were collected for histologic examination. Stable hemostasis was achieved in 11/11 BM and 5/9 CG subjects, with recovery of mean arterial pressure and animal survival for three hours (p < 0.05, Odds Ratio (OR = 18.82 (0.85–415.3. Time to stable hemostasis was shorter for the BM-treated group (4.8 ± 2.5 min vs. 58 ± 20.1 min; Median = 2, Interquartile Range (IQR = 0 min vs. Median = 60, IQR = 120 min; p < 0.05 and experienced longer total stable hemostasis (175.2 ± 2.5 min vs. 92.4 ± 29.9 min; Median = 178, IQR = 0 min vs. Median = 120, IQR = 178 min; p < 0.05. Post-treatment blood loss was lower with BM (9.5 ± 2.4 mL/kg, Median = 10.52, IQR = 13.63 mL/kg compared to CG (29.9 ± 9.9 mL/kg, Median = 29.38, IQR = 62.44 mL/kg (p = 0.2875. Standard BM products weighed less compared to CG (6.9 ± 0.03 g vs. 20.2 ± 0.4 g (p < 0.05 and absorbed less blood (3.4 ± 0.8 g vs. 41.9 ± 12.3 g (p < 0.05. Fluoroscopic angiography showed recanalization in 5/11 (BM and 0/5 (CG surviving animals (p = 0.07, OR = 9.3 (0.41–208.8. The wound stability challenge test resulted in wound re-bleeding in 1/11 (BM and 5/5 (CG surviving animals (p < 0.05, OR = 0.013 (0.00045–0.375. Histologic evidence indicated no wound site, distal limb or major

  8. Hybrid model of clot formation in flow

    Directory of Open Access Journals (Sweden)

    Tosenberger A.

    2015-01-01

    Full Text Available The process of blood coagulation and clot formation in vivo is not yet completely understood. One of the main questions related to haemostasis is why the clot stops growing in normal conditions before it completely obstructs the flow in the vessel, whereas, in pathologic cases, it can continue to grow, often with fatal consequences. Hence, revealing the mechanisms by which the clot grows and stops growing in the flow remains of great importance. In order to study this topic we have developed a hybrid DPD-PDE method where Dissipative Particle Dynamics (DPD is used to model plasma flow and platelets, while the protein regulatory network is described by a system of partial differential equations. The model describes the interaction between blood flow, platelet aggregation and plasma coagulation. As a result of modelling we propose a new mechanism of clot growth and growth arrest in flow. The developed model and its parts can be used as a base to modelling of different physiological phenomena related to cell-cell interactions and blood flows.

  9. Genomic DNA Isolation by Phenol/Chloroform Extracting Method from Sheep Blood Clot%酚/氯仿抽提法提取绵羊凝血块中基因组DNA

    Institute of Scientific and Technical Information of China (English)

    曹果清; 莫清珊; 陈凤仙

    2009-01-01

    [Objective] The aim was to establish the method of extracting genomic DNA from sheep blood clot on the basis of the improvement of method for extracting genomic DNA from tissues. [Method]The genomic DNA with complete primary structure and high purity was obtained from the sheep blood clot after the steps of cutting the sheep blood clot with ophthalmic scissors, cell lysis with tissue DNA extracts and digested by proteinase K, extracting with phenol/chloroform and precipitating with ethanol were performed. [Result]The concentration of the extracted DNA was 159.90±0.70 ng/μl and the ratio of the A260/A280 was 1.80+0.01. The sheep microsatellite locus of BM203 was amplified by using the extracted DNA from the sheep blood clot as template of PCR, and the PCR result was perfect. [Conclusion]This method is simple and feasible, the quantity and quality of the extracted DNA can satisfy the demands for the subsequent researches. It is worth to extending and using for reference.%[目的]对组织DNA提取方法进行改进,建立一种从绵羊凝血块中提取基因组DNA的方法.[方法]将绵羊凝血块用眼科剪剪碎,用组织DNA抽提液裂解细胞,用蛋白酶K消化后,经过酚/氯仿抽提,无水乙醇沉淀获得基因组DNA.用NanoDrop ND-1000微型分光光度计检测DNA浓度和纯度.用0.8%琼脂糖凝胶电泳检验基因组DNA的完整性.以绵羊微卫星位点BM203为扩增位点,分别以F:5′-GGGTGTGACATTTTGTTCCC-3′,R:5′-CTGCTCGCCACTAGTCCTTC-3′为上下游引物,进行PCR扩增试验.PCR产物用1.5%琼脂糖凝胶电泳检测.[结果]提取的DNA浓度为(159.90±0.70) ng/μl,A260/A280比值为1.80±0.01,分子完整,结果理想.以从凝血块中提取的DNA为模板,对绵羊BM203微卫星位点进行了PCR扩增,扩增产物条带整齐、明亮、特导性强,扩增效果好.[结论]该方法简单、实用,提取的DNA可满足后续相关研究对DNA质量的要求,值得推广借鉴.

  10. Preclinical testing of a new clot-retrieving wire device using polyvinyl alcohol hydrogel vascular models

    Energy Technology Data Exchange (ETDEWEB)

    Asakura, Fumio; Yilmaz, Hasan; Abdo, German; San Millan, Diego; Augsburger, Luca; Ruefenacht, Daniel A.; Lovblad, Karl-Olof [University Hospital of Geneva, Neuroradiology Unit, Geneva (Switzerland); Sekoranja, Lucka; Sztajzel, Roman; Perren, Fabienne [University Hospital of Geneva, Neurology Department, Geneva (Switzerland); Goto, Katsuya [Ohta Memorial Hospital, Neuroendovascular Section, Brain Attack Center, Ohta (Japan)

    2007-03-15

    Cerebral embolism is the principal cause of cerebral infarction. Recently, mechanical embolectomy has been proposed as an effective method. We performed a preclinical evaluation of a new mechanical clot-retrieving wire. This clot-retrieving wire consisted of three nitinol loops at the tip of a microguidewire. These three loops could be collapsed into a 0.018-inch wire compatible microcatheter. Each loop was 8 mm long and 3.5 mm wide. For simulation, polyvinyl alcohol (PVA) vascular anatomical models of the human carotid (eight models) and vertebrobasilar (three models) circulation were constructed. A pulsatile flow circulation system was used. Embolic clots were produced using pig blood plasma. The microcatheter and the microguidewire were advanced beyond the clot. The wire was then exchanged for the retrieving wire. The microcatheter was then pulled slightly back to open the loops. The clot was then caught by withdrawal of the system. Once caught, the clot was retrieved to the guiding catheter tip. We investigated the following points: ease of device deployment, clot capture ability, clot removal against blood flow and removal of the clot out of the introducer system. A total of 104 procedures were performed in 11 PVA models and evaluated. The drop rate was 19%. We succeeded in partial and total recanalization in 51.0% of the procedures (53/104) within 30 minutes. This new clot-retrieving wire could be useful for mechanical clot extraction in stroke. (orig.)

  11. Preventing Blood Clots After Hip or Knee Replacement Surgery or Surgery for a Broken Hip: A Review of the Research for ....

    Science.gov (United States)

    ... squeeze your calf and leg to increase blood flow. Stockings come in full-leg or calf lengths. Full-leg stockings may be difficult and uncomfortable to put on and take off. Intermittent pneumatic (new-MAT-ik) compression devices Leg coverings ...

  12. An Antithrombin-Heparin Complex Increases the Anticoagulant Activity of Fibrin Clots

    Directory of Open Access Journals (Sweden)

    Lesley J. Smith

    2008-01-01

    Full Text Available Clotting blood contains fibrin-bound thrombin, which is a major source of procoagulant activity leading to clot extension and further activation of coagulation. When bound to fibrin, thrombin is protected from inhibition by antithrombin (AT + heparin but is neutralized when AT and heparin are covalently linked (ATH. Here, we report the surprising observation that, rather than yielding an inert complex, thrombin-ATH formation converts clots into anticoagulant surfaces that effectively catalyze inhibition of thrombin in the surrounding environment.

  13. Photoacoustic monitoring of clot formation during surgery and tumor surgery

    Science.gov (United States)

    Juratli, Mazen A.; Galanzha, Ekaterina I.; Sarimollaoglu, Mustafa; Nedosekin, Dmitry A.; Suen, James Y.; Zharov, Vladimir P.

    2013-03-01

    When a blood vessel is injured, the normal physiological response of the body is to form a clot (thrombus) to prevent blood loss. Alternatively, even without injury to the blood vessel, the pathological condition called thromboembolism may lead to the formation of circulating blood clots (CBCs), also called emboli, which can clog blood vessels throughout the body. Veins of the extremities (venous thromboembolism), lungs (pulmonary embolism ), brain (embolic stroke), heart (myocardial infarction), kidneys, and gastrointestinal tract are often affected. Emboli are also common complications of infection, inflammation, cancer, surgery, radiation and coronary artery bypass grafts. Despite the clear medical significance of CBCs, however, little progress has been made in the development of methods for real-time detection and identification of CBCs. To overcome these limitations, we developed a new modification of in vivo photoacoustic (PA) flow cytometry (PAFC) for real-time detection of white, red, and mixed clots through a transient decrease, increase or fluctuation of PA signal amplitude, respectively. In this work, using PAFC and mouse models, we present for the first time direct evidence that some medical procedures, such as conventional or cancer surgery may initiate the formation of CBCs. In conclusion, the PA diagnostic platform can be used in real-time to define risk factors for cardiovascular diseases, assist in the prognosis and potential prevention of stroke by using a well-timed therapy or as a clot count as a marker of therapy efficacy.

  14. Dietary supplementation with dried chicory root triggers changes in the blood serum proteins engaged in the clotting process and the innate immune response in growing pigs.

    Science.gov (United States)

    Lepczynski, A; Herosimczyk, A; Ozgo, M; Skomial, J; Taciak, M; Barszcz, M; Berezecka, N

    2015-02-01

    The aim of the study was to characterize the systemic immune and metabolic alterations in the blood serum of growing pigs in response to a dietary supplementation with 4% of dried chicory roots. This was achieved by examining the influence of the experimental diet on serum protein changes especially these related with immunology and lipid metabolism. Serum proteins with the isoelectric point ranging from pH 3.0 to 10.0 were separated using high resolution two-dimensional electrophoresis. As a result, we found that experimental diet triggered significant changes in 37 protein spots. Of these, 14 were up-regulated, whereas 23 showed down-regulation. Of 37 significantly altered protein spots, 24 were successfully identified, representing 14 distinct gene products. Implementation of the dried chicory roots into the diet of growing pigs caused a significant down-regulation of apolipoprotein C-II complement component C6, C-reactive protein, CD14 antigen, C4b binding protein α and β chains, and fibrinogen. Piglets fed experimental diet had similar IgA, IgG and IgM concentrations, although the level of IgM tended to be lower compared to the control group. It is concluded that diet supplemented with 4% of dried chicory root may exert anti-inflammatory properties and affect lipid metabolism in growing pigs. PMID:25716964

  15. Prolonged Morphine Exposure Induces Increased Firm Adhesion in an in Vitro Model of the Blood-Brain Barrier.

    Science.gov (United States)

    Strazza, Marianne; Pirrone, Vanessa; Wigdahl, Brian; Dampier, Will; Lin, Wei; Feng, Rui; Maubert, Monique E; Weksler, Babette; Romero, Ignacio A; Couraud, Pierre-Olivier; Nonnemacher, Michael R

    2016-01-01

    The blood-brain barrier (BBB) has been defined as a critically important protective barrier that is involved in providing essential biologic, physiologic, and immunologic separation between the central nervous system (CNS) and the periphery. Insults to the BBB can cause overall barrier damage or deregulation of the careful homeostasis maintained between the periphery and the CNS. These insults can, therefore, yield numerous phenotypes including increased overall permeability, interendothelial gap formation, alterations in cytokine and chemokine secretion, and accelerated cellular passage. The current studies expose the human brain microvascular endothelial cell line, hCMEC/D3, to prolonged morphine exposure and aim to uncover the mechanisms underlying alterations in barrier function in vitro. These studies show alterations in the mRNA and protein levels of the cellular adhesion molecules (CAMs) intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and activated leukocyte cell adhesion molecule that correlate with an increased firm adhesion of the CD3⁺ subpopulation of peripheral blood mononuclear cells (PBMCs). Overall, these studies suggest that prolonged morphine exposure may result in increased cell migration into the CNS, which may accelerate pathological processes in many diseases that involve the BBB. PMID:27294916

  16. The clot burden score, the Boston Acute Stroke Imaging Scale, the cerebral blood volume ASPECTS, and two novel imaging parameters in the prediction of clinical outcome of ischemic stroke patients receiving intravenous thrombolytic therapy

    International Nuclear Information System (INIS)

    Recently two classification methods based on the location and the extent of thrombosis detected with CT angiography have been introduced: the Boston Acute Stroke Imaging Scale (BASIS) and the clot burden score (CBS). We studied the performance of BASIS and CBS in predicting good clinical outcome (mRS ≤2 at 90 days) in an acute (<3 h) stroke cohort treated with intravenous thrombolytic therapy. Eighty-three consecutive patients who underwent multimodal CT were analyzed. Binary logistic regression model was used to assess how BASIS, CBS, and cerebral blood volume (CBV) ASPECTS predict favorable clinical outcome. Diagnostic sensitivities and specificities were calculated and compared. Patients with low CBS and CBV ASPECTS scores and major strokes according to BASIS had significantly higher admission NIHSS scores, larger perfusion defects, and more often poor clinical outcome. In logistic regression analysis, CBV ASPECTS, CBS and BASIS were significantly associated with the clinical outcome. The performance of BASIS improved when patients with thrombosis of the M2 segment of the middle cerebral artery were classified as having minor stroke (M1-BASIS). In the anterior circulation, the sum of CBS and CBV ASPECTS (CBSV) proved to be the most robust predictor of favorable outcome. CBV ASPECTS and CBS had high sensitivity but moderate to poor specificity while BASIS was only moderately sensitive and specific. CBS, BASIS, and CBV ASPECTS are statistically robust and sensitive but unspecific predictors of good clinical outcome. Two new derived imaging parameters, CBSV and M1-BASIS, share these properties and may have increased prognostic value. (orig.)

  17. The clot burden score, the Boston Acute Stroke Imaging Scale, the cerebral blood volume ASPECTS, and two novel imaging parameters in the prediction of clinical outcome of ischemic stroke patients receiving intravenous thrombolytic therapy

    Energy Technology Data Exchange (ETDEWEB)

    Sillanpaa, Niko; Hakomaki, Jari; Lahteela, Arto; Dastidar, Prasun; Soimakallio, Seppo [Tampere University Hospital, Medical Imaging Center, Tampere (Finland); Saarinen, Jukka T.; Numminen, Heikki; Elovaara, Irina [Tampere University Hospital, Department of Neurology, Tampere (Finland); Rusanen, Harri [Oulu University Hospital, Department of Neurology, Oulu (Finland)

    2012-07-15

    Recently two classification methods based on the location and the extent of thrombosis detected with CT angiography have been introduced: the Boston Acute Stroke Imaging Scale (BASIS) and the clot burden score (CBS). We studied the performance of BASIS and CBS in predicting good clinical outcome (mRS {<=}2 at 90 days) in an acute (<3 h) stroke cohort treated with intravenous thrombolytic therapy. Eighty-three consecutive patients who underwent multimodal CT were analyzed. Binary logistic regression model was used to assess how BASIS, CBS, and cerebral blood volume (CBV) ASPECTS predict favorable clinical outcome. Diagnostic sensitivities and specificities were calculated and compared. Patients with low CBS and CBV ASPECTS scores and major strokes according to BASIS had significantly higher admission NIHSS scores, larger perfusion defects, and more often poor clinical outcome. In logistic regression analysis, CBV ASPECTS, CBS and BASIS were significantly associated with the clinical outcome. The performance of BASIS improved when patients with thrombosis of the M2 segment of the middle cerebral artery were classified as having minor stroke (M1-BASIS). In the anterior circulation, the sum of CBS and CBV ASPECTS (CBSV) proved to be the most robust predictor of favorable outcome. CBV ASPECTS and CBS had high sensitivity but moderate to poor specificity while BASIS was only moderately sensitive and specific. CBS, BASIS, and CBV ASPECTS are statistically robust and sensitive but unspecific predictors of good clinical outcome. Two new derived imaging parameters, CBSV and M1-BASIS, share these properties and may have increased prognostic value. (orig.)

  18. Procoagulant activity on platelets adhered to collagen or plasma clot.

    Science.gov (United States)

    Ilveskero, S; Siljander, P; Lassila, R

    2001-04-01

    In a new 2-stage assay of platelet procoagulant activity (PCA), we first subjected gel-filtered platelets to adhesion on collagen (as a model of primary hemostasis) or plasma clots (as a model of preformed thrombus) for 30 minutes, and then the adherent platelets were supplemented with pooled, reptilase-treated, diluted plasma. Defibrinated plasma provided coagulation factors for assembly on platelet membranes without uncontrolled binding of thrombin to fibrin(ogen). Platelet adhesion to both surfaces showed modest individual variation, which increased at platelet densities that allowed aggregation. However, adhesion-induced PCA varied individually and surface-independently >3-fold, suggesting a uniform platelet procoagulant mechanism. Permanently adhered platelets showed markedly enhanced PCA when compared with the platelet pool in suspension, even after strong activation. The rate of thrombin generation induced by clot-adherent platelets was markedly faster than on collagen-adherent platelets during the initial phase of coagulation, whereas collagen-induced PCA proceeded slowly, strongly promoted by tissue thromboplastin. Therefore at 10 minutes, after adjustment for adhered platelets, collagen supported soluble thrombin formation as much as 5 times that of the thrombin-retaining clots. Activation of platelets by their firm adhesion was accompanied by formation of microparticles, representing about one third of the total soluble PCA. Collagen-adhered platelets provide soluble thrombin and microparticles, whereas the preformed clot serves to localize and accelerate hemostasis at the injury site, with the contribution of retained thrombin and microparticles. PMID:11304482

  19. Late clotted haemothorax after blunt chest trauma.

    OpenAIRE

    Sinha, P; Sarkar, P

    1998-01-01

    A clotted haemothorax can develop any time after blunt chest trauma. Two cases are described in which late clotted haemothoraces developed which were treated by limited thoracotomy and evacuation of clots. Late clotted haemothorax may occur even in the absence of any abnormal initial clinical findings. Early detection and treatment is important to avoid the complications of fibrothorax and empyema with permanent pulmonary dysfunction. After blunt chest trauma patients should be advised to ret...

  20. 动态检测乙型肝炎患者凝血指标的临床分析*%Dynamic detection of hepatitis B patients for blood clotting index:Clinical analysis

    Institute of Scientific and Technical Information of China (English)

    余晓红; 马珍珍; 吕宏迪; 冯雨; 谢琳; 杨廷桐

    2015-01-01

    Objective To explore the clinical significance of dynamic detection of blood coagulation function in the patients with hepatitis B and cirrhosis of the liver. Methods The 182 cases of hepatitis B patients (78 cases of chronic hepatitis B,56 acute hepatitis B,cirrhosis in 48 cases) and 100 cases of in the same period normal physical body as control were collected their plasma for testing. Japanese sysmex ca7000 automatic blood coagulation instrument and auxiliary reagents were adopted for test:PT, (plasma prothrombin time),TT(thrombin time),FIB(content of fibrinogen) and APTT (activated clotting time live enzymes) and other indicators. Results Acute hepatitis B group compared with normal control group in the plasma PT,APTT,TT, FIB,there was no significant difference (P>0.05),no statistical significance. And chronic hepatitis B,liver cirrhosis group compared with normal control group,the plasma FIB content had the varying degree reduction (P<0.05),the significant differences had statistical significance;plasma PT,APTT,TT measurements had different levels of extended(P<0.05),the significant difference was statistically significant. Conclusion Blood coagulation function in patients with hepatitis B index changing with the illness and the abnormal change and dynamic detection of blood coagulation function indicators has help-guide to the patient's diagnosis ,treatment and prognosis judgement.%目的:探讨乙型肝炎及其肝硬化患者凝血功能动态检测的临床意义。方法收集182例乙肝患者(其中急性乙肝56例,慢性乙肝78例,肝硬化48例)和100例同期体检正常的对照者血浆进行检测。采用日本sysmex ca7000全自动血凝仪及配套试剂,检测:PT(血浆凝血酶原时间)、TT(凝血酶时间)、FIB(纤维蛋白原的含量)和APTT(活化部分凝血活酶时间)等指标。结果急性乙肝组与正常对照组相比,血浆PT、APTT、TT、FIB差异无显著性(P>0.05),无统计

  1. Analysis of clot formation with acoustic radiation force

    Science.gov (United States)

    Viola, Francesco; Longo, Diane M.; Lawrence, Michael B.; Walker, William F.

    2002-04-01

    Inappropriate blood coagulation plays an important role in diseases including stroke, heart attack, and deep vein thrombosis (DVT). DVT arises when a blood clot forms in a large vein of the leg. DVT is detrimental because the blood flow may be partially or completely obstructed. More importantly, a potentially fatal situation may arise if part of the clot travels to the arteries in the lungs, forming a pulmonary embolism (PE). Characterization of the mechanical properties of DVT could improve diagnosis and suggest appropriate treatment. We are developing a technique to assess mechanical properties of forming thrombi. The technique uses acoustic radiation force as a means to produce small, localized displacements within the sample. Returned ultrasound echoes are processed to estimate the time dependent displacement of the sample. Appropriate mechanical modeling and signal processing produce plots depicting relative mechanical properties (relative elasticity and relative viscosity) and force-free parameters (time constant, damping ratio, and natural frequency). We present time displacement curves of blood samples obtained during coagulation, and show associated relative and force-free parameter plots. These results show that the Voigt model with added mass accurately characterizes blood behavior during clot formation.

  2. Effects observation of Yaokang capsule to decrease pain caused by blood clotting prolapse of lower back intervertebral disc%腰康胶囊减轻淤血性腰椎间盘突出症痛痛的疗效观察

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@Background:The prolapse of the lower back intervertebral disc is a common clinical disease,the national research of recent years found that non-operation methods were important in treating the prolapse of the intervertebral discs,especially the Chinese medicine has significant effects.Yaokang capsule is made from 7 herbs as Earth worm, Frankincense and Myrrh etc it used on blood clotting prolapse of lower back intervertebral disc and satisfactory effects were achieved. Objective:To discuss the treating effects of Yaokang capsule to decrease pain caused by blood clotting prolapse of lower back intervertebral disc. Design:100 cases of prolapse of lower back intervertebral disc were randomly divided into treating group and control group.There was no difference of ages,sexes and complications between the two groups(P< 0.05).The treating effects were determined according to the scoring methods of Chinese medicine and related standards, Chi-squared test was used in statistics. Unit: Anyang District Hospital of Puyang City.

  3. Inherited Control and Firm Performance

    OpenAIRE

    Francisco Pérez-González

    2006-01-01

    I use data from chief executive officer (CEO) successions to examine the impact of inherited control on firms? performance. I find that firms where incoming CEOs are related to the departing CEO, to a founder, or to a large shareholder by either blood or marriage underperform in terms of operating profitability and market-to-book ratios, relative to firms that promote unrelated CEOs. Consistent with wasteful nepotism, lower performance is prominent in firms that appoint family CEOs who did no...

  4. What Are Rare Clotting Factor Deficiencies?

    Science.gov (United States)

    ... Pictures Young Voices Compendium of Assessment Tools Educational Games Video Library Find a Treatment Centre Haemophilia Journal About Bleeding Disorders Bleeding Disorders The Clotting Process Drugs That Can Cause Bleeding Hemophilia How Do You ...

  5. Fibrinogen concentrate improves clot strength in patients with haematological malignancies requiring platelet transfusion

    DEFF Research Database (Denmark)

    Munk-Andersen, H; Schenk, B; Larsen, O H;

    2016-01-01

    BACKGROUND: Patients with bone marrow failure secondary to chemotherapy often develop thrombocytopenia and require platelet transfusion. Fibrinogen plays an important role in platelet aggregation and the establishment of the primary haemostatic plug. OBJECTIVES: To compare the effects of in vivo...... platelet transfusion on clot firmness in thrombocytopenic patients with in vitro-performed fibrinogen concentrate substitution. MATERIALS AND METHODS: Thirty patients with haematological malignancy admitted for platelet transfusion were included. Haemostatic effects from platelet transfusion and ex vivo...... addition of fibrinogen concentrate at three different doses were evaluated by thromboelastometry, with clot firmness as the primary endpoint (A30 ExTEM assay). Secondary endpoints were other thromboelastometry parameters, thrombin generation parameters, activated partial thromboplastin time (APTT...

  6. Influence of styptic fiber on clotting time in rabbits

    Institute of Scientific and Technical Information of China (English)

    LU Jun; JIANG Su-yun

    2008-01-01

    Objective To explore the influence of styptic fiber on clotting time in rabbits so as to provide experiment data for its development. Methods Onto 0.1 mL aliquots of citrated anti-coagulant rabbit blood placed in a surfacial plate 25 ul of 0.2 mol·L-1 CaCl2 solution was dropped, and mixed well with glass stirrer;the resulting mixture was immediately capped with a piece of styptic fiber (test product group) or absorptive gelatin sponge(positive control group) of 2 cm diameter. Then, the surficial plate was rinsed with 30ml of purified water at 5, 10, 20, 30, 40 and 50 min after capping; the rinsings were allowed to stand for 1 h and were subjected to OD determination at a wavelength of 541 nm. The above procedure was repeated twice, the average value of the twice experiments was taken for evaluation of the hemostatic effect of test product. For negative control group, all procedures except for capping were same as the test product group. The haemostatic effect was judged by percent OD relative to OD at 0 min in negative control group (OD 0 min) (OD 0 min was considered as 100% );if OD value at a time was less than 80% of OD 0 min, it should be designated as primary clotting time(PCT), less than 20 96 as complete clotting time(CCT). Results The measured PCT was 20min for both negative and positive control groups;CCT was 50, 30 and 5 min for negative control, positive control and test product groups, respectively, showing the test styptic fiber had a CCT 8 times shorter than untreated blood, 10 times shorter than negative control and 6 times shorter than positive control. Conclusions The test styptic fiber has powerful hemostatic effect.

  7. 77 FR 38838 - Compliance Policy Guide Sec. 230.110-Registration of Blood Banks, Other Firms Collecting...

    Science.gov (United States)

    2012-06-29

    ... HUMAN SERVICES Food and Drug Administration Compliance Policy Guide Sec. 230.110--Registration of Blood... Administration (FDA) is announcing the withdrawal of the compliance policy guide (CPG) entitled ``Sec. 230.110.... FOR FURTHER INFORMATION CONTACT: Robert L. Hummel, Division of Compliance Policy (HFC-230), Food...

  8. Evaluation of the effects of levobupivacaine on clotting and fibrinolysis using thromboelastography.

    LENUS (Irish Health Repository)

    Leonard, S A

    2012-02-03

    Amide local anaesthetics inhibit platelet function. We hypothesized that residual anaesthetic in the epidural space could decrease efficacy of an epidural blood patch in preventing postdural puncture headache. Levobupivacaine has recently been approved for epidural anaesthesia. Its effects on coagulation have not previously been studied. The aim of this study was to determine the effects of levobupivacaine on clotting using thromboelastography. Ten ASA Class I volunteers were studied. Venous blood samples were analysed using a Haemoscope 2000D TEG analyser. Whole blood, a 50% saline control and two levobupivacaine solutions (2.5 mg mL(-1) and 2.5 microg mL(-1) in blood) were compared. The former reproduces that produced in the epidural space by blood (20 mL for an epidural blood patch) and levobupivacaine 0.5% (20 mL). The latter approximates plasma concentrations following epidural injection of levobupivacaine 0.5% (20 mL). P < 0.05 was considered significant. Maximum amplitude (MA), a measure of clot strength, is decreased by levobupivacaine 2.5 mg mL(-1). Levobupivacaine 2.5 mg mL(-1) decreases clot strength and may reduce efficacy of a prophylactic epidural blood patch.

  9. 21 CFR 173.150 - Milk-clotting enzymes, microbial.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Milk-clotting enzymes, microbial. 173.150 Section... HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.150 Milk-clotting enzymes, microbial. Milk-clotting enzyme produced by pure-culture fermentation process may be safely used in the...

  10. The Influence of a Micropolar Fluid on Peristaltic Transport in an Annulus: Application of the Clot Model

    Directory of Open Access Journals (Sweden)

    Kh. S. Mekheimer

    2008-01-01

    Full Text Available A serious pathological condition is encountered when some blood constituents deposited on the blood vessels get detached from the wall, join the blood stream again and form a clot. Study of the peristaltic transport of a micropolar fluid in an annular region is investigated under low Reynolds number and long wavelength approximations. We model a small artery as a tube having a sinusoidal wave travelling down its wall and a clot model inside it. Closed form solutions are obtained for the velocity and the microrotation components, as well as the stream function, and they contain new additional parameters, namely, δ, the height of the clot, N, the coupling number and m, the micropolar parameter. The pressure rise and friction force on the inner and the outer tubes have been discussed for various values of the physical parameters of interest.

  11. Do some of physiotherapy and rehabilitation programs improve the health state of patients suffering from cerebral clot?

    Directory of Open Access Journals (Sweden)

    Ayad OMAR

    2014-09-01

    Full Text Available Cerebral stroke represents one of the most important diseases resulting from blood clot in the middle cerebral artery, this is due to atherosclerotic clot and the brain has area of deprived blood , therefore blood becomes unable to pass the clot, in this case leads to total or partial paralysis. Rehabilitation programs are one of the most effective therapies for cerebral stroke. These pr ograms include rehabilitation exercises, therapeutic massage and kinet otherapy. The present study deals with the application of organized rehabilitation program and identify it's effect on the movement system and joints. This study examined the effect of rehabilitation program to improve the efficiency of the Locomotor system of patient who complain of cerebral stroke.

  12. Heparin Therapy during Extracorporeal Circulation: Deriving an Optimal Activated Clotting Time during Cardiopulmonary Bypass for Isolated Coronary Artery Bypass Grafting

    OpenAIRE

    Palmer, Kenneth; Ridgway, Tim; Al-Rawi, Omar; Poullis, Michael

    2012-01-01

    Bull’s seminal work on heparin therapy during cardiopulmonary bypass (CPB) was carried out over 30 years ago and has not been updated in the modern era. No correlation with postoperative blood loss was performed. The optimal activated clotting time (ACT) with regard to blood loss has not been established for patients undergoing CPB. A minimum ACT of 400 is based on the lack of visible formation of clots in the CPB circuit. The effect of heparin dose, sensitivity, metabolism, patient size, ele...

  13. Determining Human Clot Lysis Time (in vitro with Plasminogen/Plasmin from Four Species (Human, Bovine, Goat, and Swine

    Directory of Open Access Journals (Sweden)

    Omaira Cañas Bermúdez

    2015-05-01

    Full Text Available Cardiovascular disease is the leading cause of death worldwide, including failures in the plasminogen/plasmin system which is an important factor in poor lysis of blood clots. This article studies the fibrinolytic system in four species of mammals, and it identifies human plasminogen with highest thrombolysis efficiency. It examines plasminogen from four species (human, bovine, goat, and swine and identifies the most efficient one in human clot lysis in vitro. All plasminogens were identically purified by affinity chromatography. Human fibrinogen was purified by fractionation with ethanol. The purification of both plasminogen and fibrinogen was characterized by one-dimensional SDS-PAGE (10%. Human clot formation in vitro and its dissolution by plasminogen/plasmin consisted of determining lysis time from clot formation to its dilution. Purification of proteins showed greater than 95% purity, human plasminogen showed greater ability to lyse clot than animal plasminogen. The article concludes that human plasminogen/plasmin has the greatest catalysis and efficiency, as it dissolves human clot up to three times faster than that of irrational species.

  14. EspP, an Extracellular Serine Protease from Enterohemorrhagic E. coli, Reduces Coagulation Factor Activities, Reduces Clot Strength, and Promotes Clot Lysis

    OpenAIRE

    Kuo, Kevin H. M.; Khan, Shekeb; Rand, Margaret L.; Mian, Hira S.; Brnjac, Elena; Sandercock, Linda E.; Akula, Indira; Julien, Jean-Philippe; Pai, Emil F.; Chesney, Alden E.

    2016-01-01

    Background EspP (E. coli secreted serine protease, large plasmid encoded) is an extracellular serine protease produced by enterohemorrhagic E. coli (EHEC) O157:H7, a causative agent of diarrhea-associated Hemolytic Uremic Syndrome (D+HUS). The mechanism by which EHEC induces D+HUS has not been fully elucidated. Objectives We investigated the effects of EspP on clot formation and lysis in human blood. Methods Human whole blood and plasma were incubated with EspPWT at various concentrations and...

  15. Changes in clot lysis levels of reteplase and streptokinase following continuous wave ultrasound exposure, at ultrasound intensities following attenuation from the skull bone

    Directory of Open Access Journals (Sweden)

    Roijer Anders

    2008-08-01

    Full Text Available Abstract Background Ultrasound (US has been used to enhance thrombolytic therapy in the treatment of stroke. Considerable attenuation of US intensity is however noted if US is applied over the temporal bone. The aim of this study was therefore to explore possible changes in the effect of thrombolytic drugs during low-intensity, high-frequency continuous-wave ultrasound (CW-US exposure. Methods Clots were made from fresh venous blood drawn from healthy volunteers. Each clot was made from 1.4 ml blood and left to coagulate for 1 hour in a plastic test-tube. The thrombolytic drugs used were, 3600 IU streptokinase (SK or 0.25 U reteplase (r-PA, which were mixed in 160 ml 0.9% NaCl solution. Continuous-wave US exposure was applied at a frequency of 1 MHz and intensities ranging from 0.0125 to 1.2 W/cm2. For each thrombolytic drug (n = 2, SK and r-PA and each intensity (n = 9 interventional clots (US-exposed, n = 6 were submerged in thrombolytic solution and exposed to CW-US while control clots (also submerged in thrombolytic solution, n = 6 were left unexposed to US. To evaluate the effect on clot lysis, the haemoglobin (Hb released from each clot was measured every 20 min for 1 hour (20, 40 and 60 min. The Hb content (mg released was estimated by spectrophotometry at 540 nm. The difference in effect on clot lysis was expressed as the difference in the amount of Hb released between pairs of US-exposed clots and control clots. Statistical analysis was performed using Wilcoxon's signed rank test. Results Continuous-wave ultrasound significantly decreased the effects of SK at intensities of 0.9 and 1.2 W/cm2 at all times (P 2 and at 1.2 W/cm2, following 40 min exposure at 0.3, 0.6, 0.9 and at 1.2 W/cm2, and following 60 min of exposure at 0.05 0.3, 0.6, 0.9 and at 1.2 W/cm2 (all P Conclusion Increasing intensities of CW-US exposure resulted in increased clot lysis of r-PA-treated blood clots, but decreased clot lysis of SK-treated clots.

  16. A comparative study of tissue factor and kaolin on blood coagulation assays using rotational thromboelastometry and thromboelastography.

    Science.gov (United States)

    Peng, Henry T; Grodecki, Richard; Rizoli, Sandro; Shek, Pang N

    2016-01-01

    Rotational thromboelastometry (ROTEM) and thromboelastography (TEG) have been increasingly used to diagnose acute coagulopathy and guide blood transfusion. The tests are routinely performed using different triggering activators such as tissue factor and kaolin, which activate different pathways yielding different results. To optimize the global blood coagulation assays using ROTEM and TEG, we conducted a comparative study on the activation methods employing tissue factor and kaolin at different concentrations as well as standard reagents as recommended by the manufacturer of each device. Key parameter values were obtained at various assay conditions to evaluate and compare coagulation and fibrinolysis profiles of citrated whole blood collected from healthy volunteers. It was found that tissue factor reduced ROTEM clotting time and TEG R, and increased ROTEM clot formation time and TEG K in a concentration-dependent manner. In addition, tissue factor affected ROTEM alpha angle, and maximum clot firmness, especially in the absence of kaolin activation, whereas both ROTEM and TEG clot lysis (LI30, CL30, and LY30) remained unaffected. Moreover, kaolin reduced ROTEM clotting time and TEG R and K, but to a lesser extent than tissue factor, in-tem and ex-tem. Correlations in all corresponding parameters between ROTEM and TEG were observed, when the same activators were used in the assays compared with lesser correlations between standard kaolin TEG and ROTEM (INTEM/EXTEM). The two types of viscoelastic point-of-care devices provide different results, depending on the triggering reagent used to perform the assay. Optimal assay condition was obtained to reduce assay time and improve assay accuracy. PMID:26340454

  17. Thrombin-Accelerated Quick Clotting Serum Tubes: An Evaluation with 22 Common Biochemical Analytes

    Directory of Open Access Journals (Sweden)

    Wai-Yoong Ng

    2013-01-01

    Full Text Available Clot activator serum tubes have significantly improved turnaround times for result reporting compared to plain tubes. With increasing workload and service performance expectations confronting clinical laboratories with high-volume testing and with particular emphasis on critical analytes, attention has focussed on preanalytical variables that can be improved. We carried out a field study on the test performance of BD vacutainer rapid serum tubes (RSTs compared to current institutional issued BD vacutainer serum separator tubes (SSTs in its test result comparability, clotting time, and stability on serum storage. Data from the study population (n=160 of patients attending outpatient clinics and healthy subjects showed that results for renal, liver, lipids, cardiac, thyroid, and prostate biochemical markers were comparable between RSTs and SSTs. Clotting times of the RSTs were verified to be quick with a median time of 2.05 min. Analyte stability on serum storage at 4°C showed no statistically significant deterioration except for bicarbonate, electrolytes, and albumin over a period of 4 days. In conclusion, RSTs offered savings in the time required for the clotting process of serum specimens. This should translate to further trimming of the whole process from blood collection to result reporting without too much sacrifice on test accuracy and performance compared to the current widely used SSTs in most clinical laboratories.

  18. Strong Firms Lobby, Weak Firms Bribe

    DEFF Research Database (Denmark)

    Bennedsen, Morten; Feldmann, Sven E.; Lassen, David Dreyer

    We use survey responses by firms to examine the firm-level determinants and effects of political influence, their perception of corruption and prevalence of bribe paying. We find that: (a) measures of political influence and corruption/bribes are uncorrelated at the firm level; (b) firms that are...... on the government. In sum, we show that strong firms use their influence to bend laws and regulations, whereas weak firms pay bribes to mitigate the  costs of government intervention....

  19. Platelets and fibrin strands during clot retraction.

    Science.gov (United States)

    Morgenstern, E; Korell, U; Richter, J

    1984-03-15

    The ultrastructure of platelet fibrin contacts (PFC) and the course of the strands was investigated in serial sections of retracted clots with the help of specimen tilting. We found after retraction in a test tube as well as under isometric conditions in the resonance thrombograph, after HARTERT, an uniform type of PFC. The side to side contact between platelet surface and fibrin strands displayed a 15 nm wide space which was bridged of 10 - 30 nm by filamentary structure. In each case the direction of the fibrin strands changed on contact with the platelet surface (bend). These bends recurred if the adhering strands ran over a longer distance on the platelet surface. The bends can be explained by non-directional movement of the platelets or of their pseudopodia. Microfilaments (actomyosin) which run straight in pseudopodia and often also twisted in the platelet body support this assumption. The described mechanism - contact of the thrombin activated platelets with fibrin strands and simultaneous nondirectional movement of the platelets which bind further sections of the adhering strands to their surface - would provide a more satisfactory explanation for the retraction of the clot to 1/10 of its original volume. PMID:6539004

  20. Influence of Interleukin-1 Beta on Platelet-Poor Plasma Clot Formation: A Potential Impact on Early Bone Healing.

    Directory of Open Access Journals (Sweden)

    Xin Wang

    Full Text Available Hematoma quality (especially the fibrin matrix plays an important role in the bone healing process. Here, we investigated the effect of interleukin-1 beta (IL-1β on fibrin clot formation from platelet-poor plasma (PPP.Five-milliliter of rat whole-blood samples were collected from the hepatic portal vein. All blood samples were firstly standardized via a thrombelastograph (TEG, blood cell count, and the measurement of fibrinogen concentration. PPP was prepared by collecting the top two-fifths of the plasma after centrifugation under 400 × g for 10 min at 20°C. The effects of IL-1β cytokines on artificial fibrin clot formation from PPP solutions were determined by scanning electronic microscopy (SEM, confocal microscopy (CM, turbidity, and clot lysis assays.The lag time for protofibril formation was markedly shortened in the IL-1β treatment groups (243.8 ± 76.85 in the 50 pg/mL of IL-1β and 97.5 ± 19.36 in the 500 pg/mL of IL-1β compared to the control group without IL-1β (543.8 ± 205.8. Maximal turbidity was observed in the control group. IL-1β (500 pg/mL treatment significantly decreased fiber diameters resulting in smaller pore sizes and increased density of the fibrin clot structure formed from PPP (P < 0.05. The clot lysis assay revealed that 500 pg/mL IL-1β induced a lower susceptibility to dissolution due to the formation of thinner and denser fibers.IL-1β can significantly influence PPP fibrin clot structure, which may affect the early bone healing process.

  1. Your Guide to Preventing and Treating Blood Clots

    Science.gov (United States)

    ... Clinical Preventive Services Clinical Decision Support U.S. Preventive Services Task Force Improving Primary Care Practice Health IT Integration Health Care/System Redesign Clinical-Community Linkages Care ...

  2. Altered plasma fibrin clot properties in essential thrombocythemia.

    Science.gov (United States)

    Małecki, Rafał; Gacka, Małgorzata; Kuliszkiewicz-Janus, Małgorzata; Jakobsche-Policht, Urszula; Kwiatkowski, Jacek; Adamiec, Rajmund; Undas, Anetta

    2016-03-01

    Patients with increased thromboembolic risk tend to form denser fibrin clots which are relatively resistant to lysis. We sought to investigate whether essential thrombocythemia (ET) is associated with altered fibrin clot properties in plasma. Ex vivo plasma fibrin clot permeability coefficient (Ks), turbidimetry and clot lysis time (CLT) were measured in 43 consecutive patients with ET (platelet count from 245 to 991 × 10(3)/µL) and 50 control subjects matched for age, sex and comorbidities. Fibrinolysis proteins and inhibitors together with platelet activation markers were determined. Reduced Ks (-38%, p CLT (+34%, p CLT positively correlated only with PAI-1. Patients with ET display prothrombotic plasma fibrin clot phenotype including impaired fibrinolysis, which represents a new prothrombotic mechanism in this disease. PMID:25989112

  3. Identification of Quantitative Trait Loci for Fibrin Clot Phenotypes. The EuroCLOT Study

    DEFF Research Database (Denmark)

    Williams, Frances M K; Carter, Angela M; Kato, Bernet;

    2009-01-01

    OBJECTIVE: Fibrin makes up the structural basis of an occlusive arterial thrombus, and variability in fibrin phenotype relates to cardiovascular risk. The aims of the current study from the EU consortium EuroCLOT were to (1) determine the heritability of fibrin phenotypes and (2) identify QTLs...... associated with fibrin phenotypes. METHODS AND RESULTS: 447 dizygotic (DZ) and 460 monozygotic (MZ) pairs of healthy UK white female twins and 199 DZ twin pairs from Denmark were studied. D-dimer, an indicator of fibrin turnover, was measured by ELISA and measures of clot formation, morphology, and lysis......-wide linkage analysis revealed 6 significant regions with LOD >3 on 5 chromosomes (5, 6, 9, 16, and 17). CONCLUSIONS: The results indicate a significant genetic contribution to variability in fibrin phenotypes and highlight regions in the human genome which warrant further investigation in relation to ischemic...

  4. Specialized proresolving lipid mediators in patients with coronary artery disease and their potential for clot remodeling.

    Science.gov (United States)

    Elajami, Tarec K; Colas, Romain A; Dalli, Jesmond; Chiang, Nan; Serhan, Charles N; Welty, Francine K

    2016-08-01

    Inflammation in arterial walls leads to coronary artery disease (CAD). Because specialized proresolving lipid mediators (SPMs; lipoxins, resolvins, and protectins) stimulate resolution of inflammation in animal models, we tested whether n-3 fatty acids impact SPM profiles in patients with CAD and promote clot remodeling. Six patients with stable CAD were randomly assigned to either treatment with daily 3.36 g Lovaza for 1 yr or without. Targeted lipid mediator-metabololipidomics showed that both groups had absence of resolvin D1 (RvD1), RvD2, RvD3, RvD5 and resolvin E1-all of which are present in healthy patients. Those not taking Lovaza had an absence of aspirin-triggered resolvin D3 (AT-RvD3) and aspirin-triggered lipoxin B4 (AT-LXB4). Lovaza treatment restored AT-RvD3 and AT-LXB4 and gave levels of RvD6 and aspirin-triggered protectin D1 (AT-PD1) twice as high (resolvin E2 ∼5 fold) as well as lower prostaglandins. Principal component analysis indicated positive relationships for patients with CAD who were receiving Lovaza with increased AT-RvD3, RvD6, AT-PD1, and AT-LXB4 SPMs identified in Lovaza-treated patients with CAD enhanced ∼50% at 1 nM macrophage uptake of blood clots. These results indicate that patients with CAD have lower levels and/or absence of specific SPMs that were restored with Lovaza; these SPMs promote macrophage phagocytosis of blood clots. Together, they suggest that low vascular SPMs may enable progression of chronic vascular inflammation predisposing to coronary atherosclerosis and to thrombosis.-Elajami, T. K., Colas, R. A., Dalli, J., Chiang, N., Serhan, C. N., Welty, F. K. Specialized proresolving lipid mediators in patients with coronary artery disease and their potential for clot remodeling. PMID:27121596

  5. Effect of heparin on TAFI-dependent inhibition of fibrinolysis: relative importance of TAFIa generated by clot-bound and fluid phase thrombin.

    Science.gov (United States)

    Colucci, Mario; Pentimone, Anna; Binetti, Bianca M; Cramarossa, Marialisa; Piro, Donatella; Semeraro, Nicola

    2002-08-01

    Heparin has been proposed to enhance thrombolysis by inhibiting thrombin-dependent generation of activated TAFI (thrombin activatable fibrinolysis inhibitor), a carboxypeptidase that inhibits fibrinolysis. We evaluated the effect of heparin in an in vitro thrombolysis model consisting of a radiolabelled blood clot submerged in defibrinated plasma. Fibrinolysis was induced by adding t-PA (250 ng/ml) and calcium to the plasma bath. Control experiments indicated that thrombin generation induced by recalcification caused significant TAFI activation and inhibited clot lysis. Heparin (up to 1 U/ml), added to the plasma bath, failed to enhance clot lysis. Thrombin generation in the fluid phase was totally inhibited by heparin at concentrations > 0.5 U/ml. In contrast, thrombin generation on the clot surface was not inhibited by heparin (1 U/ml). TAFIa generation did occur in heparin-containing samples (1 U/ml) and amounted to about 10% of TAFIa formed in control samples. This low amount of TAFIa did exert antifibrinolytic activity as indicated by the observation that the addition of a specific TAFIa inhibitor (PTI) along with heparin enhanced clot lysis. Hirudin (10 micrograms/ml), at variance with heparin, inhibited clot-bound thrombin and enhanced clot lysis. These data show that heparin is unable to stimulate fibrinolysis through a TAFI-dependent mechanism, most likely because of its inefficiency in inhibiting thrombin generation on the clot surface. Moreover, they suggest that clot-bound thrombin plays a major role in TAFI-mediated inhibition of fibrinolysis through "localized" TAFIa generation. PMID:12195701

  6. C-reactive protein prolongs blood coagulation time in phospholipids-dependent coagulation tests

    Directory of Open Access Journals (Sweden)

    L D Kozmin

    2003-01-01

    Full Text Available C-refctive protein prolongs blood coagulation time in phospholipids-dependent coagulation tests. O.P. Bliznukov, L.D. Kostin, A.J. Martinov, T.A. Lisitsina, T.M. Reshetnyak, V.J. Lauga Objective. To study influence of different CRP forms on blood clotting time in standard phospholipid clotting tests. Material and methods. Purified native CRP. monomeric CRP (0-1.6 M, immune complexes of native CRP and rabbit polyclonal anti-CRP antibodies (1.6 M were added to blood plasma of healthy donors. Blood clotting time was registered using optical coagulometer. Phospholipid dependent prothrombin time (PT, activated partial tromboplastin time (APTT, kaolin clotting time (KCT with kaolin and ellagic acid, dilute Russel viper venom time (dRVVT were determined. Results. Native CRP was able to increase blood clotting time in all mentioned clotting tests, excluding prothrombin time. CRP influence on blood clotting time showed a concentration dependence. Polyclonal rabbit anti-CRP antibodies had no inhibitory effect on CRP prolonged blood clotting time. Monomeric CRP (0-1.6 M had no influence on blood clotting time in all phospholipid-dependent clotting tests.

  7. What Is Combined Deficiency of Vitamin K-Dependent Clotting Factors?

    Science.gov (United States)

    ... Pool Deficiencies Home About Bleeding Disorders What is combined deficiency of vitamin K-dependent clotting factors? Inherited combined deficiency of the vitamin K-dependent clotting factors ( ...

  8. ICT, Complementary Firm Strategies and Firm Performance

    OpenAIRE

    Rasel, Fabienne

    2016-01-01

    This doctoral thesis analyses from different perspectives the relationship between information and communication technologies (ICT), complementary firm strategies and firm performance. One chapter examines the role of ICT and decentralized workplace organization for productivity. Two chapters analyse the association between firms' ICT use, international trade activities and productivity. The empirical analyses are based on data from firms located in Germany from the manufacturing or service s...

  9. Evaluation of ovine milk clotting aptitude

    Directory of Open Access Journals (Sweden)

    A. Caroli

    2010-01-01

    Full Text Available A comparative study of the lactodynamographic parameters was carried out on ovine milk. Besides evaluating the repeatability and reproducibility of the analytical method, the influence of some variables such as the genetic type (three breeds, the kind of milk (whole or skimmed, and its concentration after reconstitution (12g or 20g /100 ml was evaluated. The working plan involved 6 laboratories for the final statistic analyses, by the use of freeze-dried milk samples (adequately reconstituted on the basis of established methods from Sardinia, Comisana, and Massese ewes. All the considered variability factors showed a highly significant effect (P<0.001 on the lactodynamographic parameters considered. In particular, Massese ewe milk showed the shortest curd speed (k20 and the best coagulum strength (a30 and a45, although clotting time (CT was the highest one. The same trend was registered for skimmed milk and for the most concentrated one (20g. Repeatability values within laboratories were 96% and 97% for CT and k20, lowering for a30 e a45, (respectively 87% and 85%. Much lower coefficients were found for the among laboratories reproducibility, ranging from a maximum of 58% for CT to a minimum of 18% for k20. The wide variability observed indicates that lactodynamographic parameters are comparable only within the same lab. Further investigation is needed to compare different labs in order to obtain more homogeneous results.

  10. Problems concerning ovine milk clotting aptitude

    Directory of Open Access Journals (Sweden)

    M. Martini

    2003-01-01

    Full Text Available A comparative study of the lactodynamographic parameters was carried out on ovine milk. Besides evaluating the repeatability and reproducibility of the analytical method, the influence of some variables such as the genetic type (three breeds, the kind of milk (whole or skimmed, and its concentration after reconstitution (12g or 20g /100 ml was evaluated. The working plan involved 6 laboratories for the final statistic analyses, by the use of freeze-dried milk samples (adequately reconstituted on the basis of established methods from Sardinia, Comisana, and Massese ewes. All the considered variability factors showed a highly significant effect (P<0.001 on the lactodynamographic parameters considered. In particular, Massese ewe milk showed the shortest curd speed (k20 and the best coagulum strength (a30 and a45, although clotting time (CT was the highest one. The same trend was registered for skimmed milk and for the most concentrated one (20g. Repeatability values within laboratories were 96% and 97% for CT and k20, lowering for a30 e a45, (respectively 87% and 85%. Much lower coefficients were found for the among laboratories reproducibility, ranging from a maximum of 58% for CT to a minimum of 18% for k20. The wide variability observed indicates that lactodynamographic parameters are comparable only within the same lab. Further investigation is needed to compare different labs in order to obtain more homogeneous results.

  11. Clotting mechanism in beagles irradiated by 4.5 Gy γ-rays

    International Nuclear Information System (INIS)

    Objective: To explore the clotting mechanism in beagles irradiated by 4.5 Gy γ-rays after treatment with supportive care, or supportive care and combined cytokines. Methods: Sixteen beagles were divided into irradiation control group, Supportive care group and combined cytokines treatment group. Platelet aggregation test, thrombelastography (TEG) and the time measurement were analyzed in vitro. Results: In irradiation group and supportive care group, the platelet aggregation rates in beagles were decreased markedly and the k value of TEG was increased 7 d post-irradiation, while those indexes in combined cytokines treatment group changed little. At 14 d post-irradiation, each parameter of TEG in irradiated group changed obviously. The values of r, k, r + k and M were elevated significantly, clotting time and the maximum coagulation time of thrombus delayed, the Ma value was decreased markedly, and the maximum elasticity amplitude of thrombus was diminished. All parameters in combined cytokines treatment group were better than those in supportive care group. The thrombin time was prolonged obviously in irradiated group 14 d post-irradiation, while the thrombin time was the longest at 2-3 weeks post irradiation in supportive care group and combined cytokines treatment group (P>0.05). Conclusions: Cytokines could improve the platelet aggregation and the blood clotting functions of beagles suffering from acute radiation sickness. (authors)

  12. Clotting of mammalian fibrinogens by papain: A re-examination

    OpenAIRE

    Doolittle, RF

    2014-01-01

    © 2014 American Chemical Society. Papain has long been known to cause the gelation of mammalian fibrinogens. It has also been reported that papain-fibrin is insoluble in dispersing solvents like strong urea or sodium bromide solutions, similar to what is observed with thrombin-generated clots in the presence of factor XIIIa and calcium. In those old studies, both the gelation and subsequent clot stabilization were attributed to papain, although the possibility that the second step might be du...

  13. Thromboelastography on plasma reveals delayed clot formation and accelerated clot lyses in HIV-1 infected persons compared with healthy controls

    DEFF Research Database (Denmark)

    Rönsholt, Frederikke Falkencrone; Gerstoft, Jan; Ullum, Henrik;

    2015-01-01

    measured levels of C-reactive protein, thrombomodulin, syndecan-1, sVE-cadherin, soluble CD40 ligand (sCD40L), adrenaline and noradrenaline. RESULTS: Compared to CON, HIV+ had delayed clot formation (reaction (R)-time 14.2 min. vs. 11.2 min., p = 0.0004) and reduced clot formation rapidity (angle 22.6° vs...

  14. Firm Acquisitions Strategy

    OpenAIRE

    Conf.univ.dr.ec. Adrian SIMON,

    2010-01-01

    We analyze the intents of acquiring firms and target in the firms in the case of thirty recent M$A deals involving at least one firm. The findings indicate that horizontal acquisitions help retain or gain market leadership. Market entry may be a dominant motive for MNCs acquiring domestic firms, and MNCs may offer higher premiums than domestic acquirers for the acquisition

  15. Thermodynamics of firms' growth

    OpenAIRE

    Eduardo Zambrano; Alberto Hernando; Aurelio Fernandez-Bariviera; Ricardo Hernando; Angelo Plastino

    2015-01-01

    The distribution of firms' growth and firms' sizes is a topic under intense scrutiny. In this paper, we show that a thermodynamic model based on the maximum entropy principle, with dynamical prior information, can be constructed that adequately describes the dynamics and distribution of firms' growth. Our theoretical framework is tested against a comprehensive database of Spanish firms, which covers, to a very large extent, Spain's economic activity, with a total of 1 155 142 firms evolving a...

  16. Colombia Firm Energy Market

    OpenAIRE

    Peter Cramton; Steven Stoft

    2007-01-01

    A firm energy market for Colombia is presented. Firm energy—the ability to provide energy in a dry period—is the product needed for reliability in Colombia’s hydro-dominated electricity market. The firm energy market coordinates investment in new resources to assure that sufficient firm energy is available in dry periods. Load procures in an annual auction enough firm energy to cover its needs. The firm energy product includes both a financial call option and the physical capability to supply...

  17. Procurement with specialized firms

    DEFF Research Database (Denmark)

    Schottmüller, Christoph; Boone, Jan

    2016-01-01

    This paper analyzes optimal procurement mechanisms when firms are specialized. The procurement agency has incomplete information concerning the firms’ cost functions and values high quality as well as low price. Lower type firms are cheaper (more expensive) than higher type firms when providing l...

  18. Procurement with specialized firms

    DEFF Research Database (Denmark)

    Schottmüller, Christoph; Boone, Jan

    2016-01-01

    This paper analyzes optimal procurement mechanisms when firms are specialized. The procurement agency has incomplete information concerning the firms’ cost functions and values high quality as well as low price. Lower type firms are cheaper (more expensive) than higher type firms when providing low...

  19. The euglobulin clot lysis time to assess the impact of nanoparticles on fibrinolysis

    Energy Technology Data Exchange (ETDEWEB)

    Minet, Valentine, E-mail: valentine.minet@unamur.be; Alpan, Lutfiye; Mullier, François [University of Namur – UNamur, Department of Pharmacy, Namur Thrombosis and Hemostasis Center (NTHC), Namur Nanosafety Center (NNC), NAmur Research Institute for Life Sciences NARILIS (Belgium); Toussaint, Olivier [Laboratory of Cellular Biochemistry and Biology (URBC) (Belgium); Lucas, Stéphane [University of Namur (UNamur), Research Centre for the Physics of Matter and Radiation (PMR-LARN), Namur Nanosafety Center NNC, NAmur Research Institute for Life Sciences NARILIS (Belgium); Dogné, Jean-Michel; Laloy, Julie, E-mail: julie.laloy@unamur.be [University of Namur – UNamur, Department of Pharmacy, Namur Thrombosis and Hemostasis Center (NTHC), Namur Nanosafety Center (NNC), NAmur Research Institute for Life Sciences NARILIS (Belgium)

    2015-07-15

    Nanoparticles (NPs) are developed for many applications in various fields, including nanomedicine. The NPs used in nanomedicine may disturb homeostasis in blood. Secondary hemostasis (blood coagulation) and fibrinolysis are complex physiological processes regulated by activators and inhibitors. An imbalance of this system can either lead to the development of hemorrhages or thrombosis. No data are currently available on the impact of NPs on fibrinolysis. The objectives of this study are (1) to select a screening test to study ex vivo the impact of NPs on fibrinolysis and (2) to test NPs with different physicochemical properties. Euglobulin clot lysis time test was selected to screen the impact of some NPs on fibrinolysis using normal pooled plasma. A dose-dependent decrease in the lysis time was observed with silicon dioxide and silver NPs without disturbing the fibrin network. Carbon black, silicon carbide, and copper oxide did not affect the lysis time at the tested concentrations.

  20. The euglobulin clot lysis time to assess the impact of nanoparticles on fibrinolysis

    International Nuclear Information System (INIS)

    Nanoparticles (NPs) are developed for many applications in various fields, including nanomedicine. The NPs used in nanomedicine may disturb homeostasis in blood. Secondary hemostasis (blood coagulation) and fibrinolysis are complex physiological processes regulated by activators and inhibitors. An imbalance of this system can either lead to the development of hemorrhages or thrombosis. No data are currently available on the impact of NPs on fibrinolysis. The objectives of this study are (1) to select a screening test to study ex vivo the impact of NPs on fibrinolysis and (2) to test NPs with different physicochemical properties. Euglobulin clot lysis time test was selected to screen the impact of some NPs on fibrinolysis using normal pooled plasma. A dose-dependent decrease in the lysis time was observed with silicon dioxide and silver NPs without disturbing the fibrin network. Carbon black, silicon carbide, and copper oxide did not affect the lysis time at the tested concentrations

  1. Transformation of Manufacturing Firms to Servitisation Firms

    DEFF Research Database (Denmark)

    Lin, Chih-Cheng; Ma, Zheng; Tanev, Stoyan

    2014-01-01

    traditional manufacturing firm to service-oriented firms is the conspicuous lack of publications in this research stream. Applying a case study research approach, this study explores the transformation model for manufacturing SMEs to servitisation firms by adopting a network approach, and reveals the......It is crucial for the manufacturing SMEs to reconsider their business strategy in order to be able to launch customer-centric solutions. This ability is associated with a paradigm shift from a product-orientation to service-orientation. One of the major challenges to success in transforming a...

  2. Transfusion packages for massively bleeding patients: the effect on clot formation and stability as evaluated by Thrombelastograph (TEG)

    DEFF Research Database (Denmark)

    Johansson, Per Ingemar; Bochsen, L.; Stensballe, J.;

    2008-01-01

    We investigated the effect of administering a transfusion package encompassing 5 red blood cells (RBC), 5 fresh frozen plasma (FFP), and 2 platelet concentrates (PC) on clot formation and stability as evaluated by Thrombelastograph (TEG) in 10 patients presenting with massive bleeding. Blood...... was obtained before and after administering the transfusion packages. Six patients were hypocoagulable before administration of the transfusion package, whereas none of the patients were hypocoagulable after transfusion of up to 7 transfusion packages (p=0.01). In 8 patients damage control surgery...

  3. Input reallocation within firms

    OpenAIRE

    Vandenbussche, Hylke; Viegelahn, Christian

    2016-01-01

    This paper documents the within firm reallocation of inputs and outputs as a result of a trade policy shock on the input side. A unique firm-input level dataset for India with information on different raw material inputs used in production, enables us to identify firms with imported inputs subject to trade policy. To guide the empirics, we first develop a back-bone model of heterogeneous firms that source inputs from abroad. We find that affected firms engage in input reallocation and lower t...

  4. Performance of Patenting Firms

    DEFF Research Database (Denmark)

    Madsen, Erik Strøjer; Smith, Valdemar; Nielsen, Anders Østergaard

    2000-01-01

    Most countries focus on industries with high technology and the governments grant subsidies to innovating firms. However, there has been remarkable few studies of the performance of innovative firms or industries. This study examines the performance of patent active firms compared to the non-patenting...... firms within the manufacturing sector in Denmark. Performance is measured both by growth in employment as well as in the return on equity and profit share in turnover. The results suggest that differences in performance of patenting and non-patenting firms are very small, which questions the political...

  5. Simultaneous comparison of thrombogenic reactions to different combinations of anticoagulants, activated clotting times, and materials.

    Science.gov (United States)

    Nagai, Mirei; Iwasaki, Kiyotaka; Umezu, Mitsuo; Ozaki, Makoto

    2014-11-01

    Thrombogenic reactions under multiple interactions of pharmacological agents, doses, and materials have not been well understood yet. The aim of this study was to investigate the ability to simultaneously compare thrombogenic reactions to different combinations of anticoagulants, doses, and blood-contacting materials, in a single human blood using an in vitro test method. Four venous blood samples were drawn from each of six healthy volunteers into syringes that contained two different amounts of heparin and argatroban to set the activated clotting time (ACT) to approximately 200 or 500 s, respectively. The four blood samples from each volunteer were immediately poured into two clinical-grade extracorporeal circulation tubes: a polyvinyl chloride (PVC) tube and a poly(2-methoxyethyl acrylate)-coated (PMEA) PVC tube. These tubes with an inner diameter of 12.7 mm were rotated at 183 rpm in a 37°C chamber for 10 min. The results indicated that the in vitro thrombogenicity test method was capable of assessing differences in platelet factor 4 and β-thromboglobulin increases among different combinations of the two materials, two anticoagulants, and two ACTs. Higher amounts of total plasma proteins were absorbed on PVC tubes than on PMEA-coated tubes when using the same anticoagulant and dose. These data elucidate that the in vitro thrombogenicity test method is useful for the simultaneous quantitative evaluation of the influences of various combinations of materials, pharmacological agents, and doses on thrombogenicity in a single human blood. PMID:24652689

  6. Audits of private firms

    OpenAIRE

    Langli, John Christian; Svanström, Tobias

    2013-01-01

    Private and public firms differ across a number of important dimensions. Public firms are under scrutiny by stock exchanges, regulators, and market participants and they share the feature of separation of ownership and control. Private firms, in contrast, are much less regulated, the nature of their agency problems is different, they are less exposed to market forces, litigation and publicity, and they operate in a much more opaque information environment. The greater heterogeneit...

  7. Firming up inequality

    OpenAIRE

    Song, Jae; Price, David J.; Guvenen, Fatih; Bloom, Nick

    2015-01-01

    Earnings inequality in the United States has increased rapidly over the last three decades, but little is known about the role of firms in this trend. For example, how much of the rise in earnings inequality can be attributed to rising dispersion between firms in the average wages they pay, and how much is due to rising wage dispersion among workers within firms? Similarly, how did rising inequality affect the wage earnings of different types of workers working for the same employ...

  8. Immigration and Firm Expansion

    OpenAIRE

    William W. Olney

    2008-01-01

    Research generally focuses on how immigration affects native workers, while the impact of immigration on domestic firms is often overlooked. This paper addresses this important omission by examining whether firms respond to immigration by expanding their production activities within a city in order to utilize the abundant supply of low-skilled workers. Using data on immigration and the universe of establishments in U.S. cities, the results indicate that firms respond to immigration at the ext...

  9. Firm Ownership and Philanthropy

    OpenAIRE

    Chai, D.H.

    2010-01-01

    This paper empirically examines the relationship between firm ownership structure and corporate charitable donations. Using a panel data set of 1,017 listed Korean firms, we find that larger firms with higher advertising intensity and lower export intensity 'give' relatively more, suggesting that charitable donations are both strategic and discretionary corporate expenditures. In addition, the study explores the effects of ownership structure on corporate philanthropy. We find a positive rela...

  10. The market for firms

    DEFF Research Database (Denmark)

    Davis, Jerome Dean; Keiding, Hans

    2010-01-01

    In this paper, the pricing and sale of firms is approached from the owners' point of view. It is shown that there are very strong ex ante owner incentives to set prices of firm products or services below their short- term profit maximizing levels, since low prices signal low costs and as a...... consequence a higher sales value of the firm. Buyers take this signaling into consideration, but irrespective of their countermoves, the equilib- rium result may be a lowering of ex ante product prices, and an ex post market overvaluation of the firm. This model is utilized to suggest possible explanations to...

  11. Foreign Firms, Domestic Wages

    DEFF Research Database (Denmark)

    Malchow-Møller, Nikolaj; Markusen, James R.; Schjerning, Bertel

    Foreign-owned firms are often hypothesized to generate productivity "spillovers" to the host country, but both theoretical micro-foundations and empirical evidence for this are limited. We develop a heterogeneous-firm model in which ex-ante identical workers learn from their employers in proportion...... similarly large domestic firms. The empirical implications of the model are tested on matched employer-employee data from Denmark. Consistent with the theory, we find considerable evidence of higher wages and wage growth in large and/or foreign-owned firms. These effects survive controlling for individual...

  12. Thermodynamics of firms' growth

    CERN Document Server

    Zambrano, Eduardo; Fernandez-Bariviera, Aurelio; Hernando, Ricardo; Plastino, Angelo

    2015-01-01

    The distribution of firms' growth and firms' sizes is a topic under intense scrutiny. In this paper we show that a thermodynamic model based on the Maximum Entropy Principle, with dynamical prior information, can be constructed that adequately describes the dynamics and distribution of firms' growth. Our theoretical framework is tested against a comprehensive data-base of Spanish firms, which covers to a very large extent Spain's economic activity with a total of 1,155,142 firms evolving along a full decade. We show that the empirical exponent of Pareto's law, a rule often observed in the rank distribution of large-size firms, is explained by the capacity of the economic system for creating/destroying firms, and can be used to measure the health of a capitalist-based economy. Indeed, our model predicts that when the exponent is larger that 1, creation of firms is favored; when it is smaller that 1, destruction of firms is favored instead; and when it equals 1 (matching Zipf's law), the system is in a full mac...

  13. Foreign Firms, Domestic Wages

    DEFF Research Database (Denmark)

    Malchow-Møller, Nikolaj; Schjerning, Bertel; R. Markusen, James

    2013-01-01

    Three types of theories have been used to explain the wage premium in foreign firms: the theories of heterogeneous workers, heterogeneous learning, and heterogeneous firms. We set up a model that explicitly encompasses two of these theories, and that can illustrate the third. This unifying...

  14. Inside the Family Firm

    DEFF Research Database (Denmark)

    Bennedsen, Morten; Nielsen, Kasper; Pérez-González, Francisco;

    2005-01-01

    -child family firms are more likely to pass on control to a family CEO than female first-child firms, but the gender of the first child is unlikely to affect firms' performance. We find that family successions have a dramatic negative causal impact on firm performance: profitability on assets falls by at least......This paper uses a unique dataset from Denmark to investigate (1) the role of family characteristics in corporate decision making, and (2) the consequences of these decisions on firm performance. We focus on the decision to appoint either a family or an external chief executive officer (CEO). We...... show that a departing CEO's family characteristics have a strong predictive power in explaining CEO succession decisions: family CEOs are more frequently selected the larger the size of the family, the higher the ratio of male children and when the departing CEOs had only had one spouse. We then...

  15. Foreign Firms, Domestic Wages

    DEFF Research Database (Denmark)

    Malchow-Møller, Nikolaj; Markusen, James R.; Schjerning, Bertel

    developing a model that allows for two "pure" explanations for the wage premium. The first is a heterogenous-worker explanation along the lines of Yeaple (2005), where firms that select more scaleintensive technologies select ex-ante more productive workers. In this case, the wage premium is a pure selection...... phenomenon. The second explanation builds on the heterogeneous-firm model of Melitz (2003) combined with on-the-job learning as in Markusen (2001). Productivity differences between firms are internalized by ex-ante homogeneous workers, so the wage premium is a pure learning phenomenon due to ex-post higher...... productivity in foreign firms. Our model yields a number of precise empirical hypotheses. When these predictions are tested on Danish matched employer-employee data, we find that both explanations play a role in explaining the observed wage premium. Specifically, the foreign- and large-firm premiums explained...

  16. Does Corporate Governance Influence Firm Value? Evidence from Indian Firms

    OpenAIRE

    Kumar, Jayesh

    2004-01-01

    This paper examines empirically the effects of ownership structure on the firm performance for a panel of Indian corporate firms, from a corporate governance perspective. We examine the effect of interactions between corporate, foreign, institutional, and directorial ownership on firm performance. Using firm level panel data framework, we show that a large fraction of cross-sectional variation, in firm performance, can be explained by unobserved firm heterogeneity. We also provide evidence th...

  17. Corruption and firm performance: Evidence from Greek firms

    OpenAIRE

    Athanasouli, Daphne; Goujard, Antoine; Sklias, Pantelis

    2012-01-01

    This article investigates the relationship between corruption and firm performance in Greece using firm level data. Corruption is overall negatively associated with firm size and growth at the firm level. We focus on the effect of ‘administrative corruption’, whereby firms engage in corrupt practices and bribery of government officials. We contrast the firm experience of corruption and the contextual experience of corruption at the sectoral level and find that the latter, contextual corruptio...

  18. PARTIAL PURIFICATION OF MILK-CLOTTING ENZYME FROM THE SEEDS OF MORINGA OLEIFERA

    Directory of Open Access Journals (Sweden)

    Amna E. Tajalsir

    2014-08-01

    Full Text Available The aim of the present study was to search for milk clotting substitute from different parts (flowers, seeds, stem, leaves, ripe and unripe fruits of Moringa oleifera. The samples were blended and extracted using different types of extracting solutions. The most reliable, quick and efficient enzyme extracting solution was found to be 5% NaCl in 100 mM sodium acetate buffer, pH 5.0, which was used throughout the study. The milk clotting activity was only observed in the seeds extract while the other parts were either deficient or has very low milk clotting activity. Thus, the moringa seeds were used as source of milk clotting enzyme. The extracted proteins were fractionated with ammonium sulfate at concentration of 20, 30, 40, 50 and 60 %. Highest milk clotting activity was observed in the 20 % fraction. This fraction was assumed to contain the clotting enzymes and characterized for its heating stability (30 – 90°C and optimum temperature (30 – 90°C. The results demonstrated that moringa seeds milk clotting enzyme is stable up to 50°C with an optimum milk clotting activity of 70°C. The high ratio of milk-clotting to proteolytic activity of the partially purified enzyme indicates the potential of this enzyme as suitable rennet substitute in dairy industry. However, further study is needed to completely purify and characterize this promising milk clotting enzyme from moringa seeds.

  19. Global Sourcing and Firm Selection

    DEFF Research Database (Denmark)

    Kohler, Wilhelm; Smolka, Marcel

    2014-01-01

    We analyze the sourcing strategies of firms active in the Spanish manufacturing sector. We show that firms that select strategies of vertical integration and of foreign sourcing ex post tend to have been more productive, ex ante, than other firms.......We analyze the sourcing strategies of firms active in the Spanish manufacturing sector. We show that firms that select strategies of vertical integration and of foreign sourcing ex post tend to have been more productive, ex ante, than other firms....

  20. Global Sourcing and Firm Selection

    OpenAIRE

    Kohler, Wilhelm; Smolka, Marcel

    2013-01-01

    Which firms find it optimal to integrate their input suppliers into the firm boundaries of control (vertical integration)? Which firms choose to expand their sourcing activities across the national border (offshoring)? This letter provides novel evidence on these questions based on a Spanish firm-level data set. We find that firms selecting into strategies of vertical integration and of offshoring tend to have been more productive ex ante than firms choosing not to do so. This finding is in l...

  1. Firming Up Inequality

    OpenAIRE

    Jae Song; Price, David J.; Fatih Guvenen; Nicholas Bloom; Till von Wachter

    2015-01-01

    Earnings inequality in the United States has increased rapidly over the last three decades, but little is known about the role of firms in this trend. For example, how much of the rise in earnings inequality can be attributed to rising dispersion between firms in the average wages they pay, and how much is due to rising wage dispersion among workers within firms? Similarly, how did rising inequality affect the wage earnings of different types of workers working for the same employer—men vs. w...

  2. Collaborative Communities of Firms

    DEFF Research Database (Denmark)

    Bøllingtoft, Anne; Müller, Sabine; Ulhøi, John Parm;

    2011-01-01

    is an organizational model called the collaborative community of firms. This chapter addresses an important organizational role in a collaborative community, that of the shared services provider. The shared services provider acts as a facilitator in the community, helping member firms collaborate with one another...... and developing strategic initiatives that aid the community as a whole. We discuss the facilitator role of the shared services provider, contrasting it with the coordinator role found in other multi-firm organizations, and we show how shared services providers function by describing three examples...

  3. Staying Active and Healthy: Blood Thinners

    Medline Plus

    Full Text Available Referenced Links: Review the following links for additional information on this topic: • Blood Thinner Pills: Your Guide to Using Them Safely ... the following related programs are offered for your review: Preventing Blood Clots After Hip or Knee Surgery ...

  4. Firm Financial Policy

    Directory of Open Access Journals (Sweden)

    Alexandru NEGREA

    2014-11-01

    Full Text Available Financial policy outlines the main directions of action of the financial activity. In determining financial policy, managers must take into consideration interests of all stakeholders, given the political, social, financial and monetary context of the firm, but also the technical and technological one. In addition, the educational, environmental and scientific context must be considered when establishing the financial policy, as it also influences the latter. Therefore, within financial policy, managers must identify and adopt those financial decisions that can positively influence the future development of the firm. Present studies intended as a tool for those interested in the future of the firm, e.g. employers, employees, banks, insurance companies, service providers, etc. It details directions of actions used by managers within financial policy in order to increase firm profits.

  5. Collaborative Communities of Firms

    DEFF Research Database (Denmark)

    Bøllingtoft, Anne; Müller, Sabine; Ulhøi, John Parm; Snow, Charles C.

    organizational model called the collaborative community of firms. This chapter addresses an important organizational role in a collaborative community, that of the shared services provider. The shared services provider acts as a facilitator in the community, helping member firms collaborate with one another and...... developing strategic initiatives that aid the community as a whole. We discuss the facilitator role of the shared services provider, contrasting it with the coordinator role found in other multi-firm organizations, and we show how shared services providers function by describing three examples of...... collaborative communities of firms from different sectors: the U.S.-based Blade.org and two Denmark-based communities, the Kalundborg Industrial Symbiosis and MG50. Implications for the theory and practice of organization design are discussed....

  6. Travail et pouvoir d’agir d’Yves Clot

    Directory of Open Access Journals (Sweden)

    Jacques Leplat

    2008-11-01

    Full Text Available Yves Clot est titulaire de la Chaire de psychologie du travail du Conservatoire National des Arts et Métiers (CNAM au sein duquel il dirige l’équipe de clinique de l’activité. Cet ouvrage est le second qu’il publie dans cette collection, le premier « La fonction psychologique du travail » est paru en 1999. Entre les deux s’inscrivent un grand nombre de publications, dont beaucoup avec d’autres chercheurs, comme on pourra le constater en consultant la bibliographie de ce livre. Ce denier réun...

  7. Information theory of firm

    OpenAIRE

    Ledenyov, Dimitri O.; Ledenyov, Viktor O.

    2015-01-01

    The article formulates the information theory of firm, introduces the concept of firm as an operating system, which controls the firm’s operation by the means of the information resources processing, in an analogy with the operating system at a microprocessor in the computing devices, represents the director as an information processing element, describes the board of directors as the electronically-scanned electronically-steered phased array radar, considers the scientific problem of strateg...

  8. How Entrepreneurial Firms Prosper while Larger Firms Crumble

    OpenAIRE

    Shukla, P K

    2009-01-01

    Many firms are facing great difficulty surviving the declining financial markets in Fall 2008. As larger firms take drastic measures to control and cut costs while forecasting declining revenue, entrepreneurial firms view the same marketplace in a more positive light. What separate these two types of firms is their differing levels of entrepreneurial intensity.An entrepreneurial grid positions firms upon two dimensions: Frequency of Entrepreneurship and Degree of Entrepreneurship (innovativen...

  9. Global sourcing of family firms

    OpenAIRE

    Horgos, Daniel

    2010-01-01

    In Europe, a huge share of firms is family owned. Since family firms are known to be more risk averse concerning international transactions, an interesting question emerges: Do family firms adopt a different international sourcing pattern. Altering the Gloubal Sourcing model of Antràs and Helpman, this theoretical contribution adopts a family firm's perspective. The model shows that family firms tend to decrease international procurement. In the headquarter intensive sector, where FDI coexist...

  10. Global Sourcing of Familiy Firms

    OpenAIRE

    Horgos, Daniel

    2010-01-01

    In Europe, a huge share of firms is family owned. Since family firms are known to be more risk averse concerning international transactions, an interesting question emerges: Do family firms adopt a different international sourcing pattern. Altering the Gloubal Sourcing model of Antràs and Helpman, this theoretical contribution adopts a family firm's perspective. The model shows that family firms tend to decrease international procurement. In the headquarter intensive sector, where FDI coexist...

  11. Innovation in Family Firms

    DEFF Research Database (Denmark)

    Filser, Matthias; Brem, Alexander; Gast, Johanna;

    2016-01-01

    Over the past decade, research on innovation in family firms has received growing attention by scholars and practitioners around the globe with a wide range of aspects explored within the current body of literature. Despite the constantly growing number of scientific publications, research lacks a...... comprehensive and critical review of past and present research achievements. First, conducting a bibliometric analysis with a focus on innovation in family firms, we identify five topical clusters that help to understand the foundations of recent findings: namely ownership and governance, structural settings......, organizational culture and behaviour, resources, and innovation and strategy. Second, based on a thorough literature review the major research avenues are reflected. The comparison of the results of both analyses showed the following areas for future research on family firm innovation: members‘ individual human...

  12. Which firms use measures?

    DEFF Research Database (Denmark)

    Pedersen, Esben Rahbek Gjerdrum; Sudzina, Frantisek

    2012-01-01

    Purpose – The purpose of this paper is to outline the anatomy of firms which adopt comprehensive performance measurement (PM) systems in order to gain an understanding of how internal (organisational capabilities) and external (perceived environmental uncertainties) factors shape performance...... measurement practices. Design/methodology/approach – This paper hypothesises that firms dominated by organic capabilities and operating in unpredictable markets are more likely to adopt comprehensive PM systems. The statistical test of these hypotheses is based on a 2008 survey of 299 Danish firms. Findings...... – This paper concludes that a limited number of internal and external factors have a significant influence on the adoption of PM systems. There is no consistent pattern, however, between the different sub-categories of organisational capabilities/perceived environmental uncertainties and PM adoption...

  13. Effect of spirapril and hydrochlorothiazide on platelet function and euglobulin clot lysis time in patients with mild hypertension

    DEFF Research Database (Denmark)

    Fonitz, Gitte (Gleerup); Petersen, J R; Mehlsen, J; Winther, Kaj

    1996-01-01

    Thirteen patients with mild hypertension (untreated diastolic blood pressure of 95 to 114 mmHg) received, in random order, three successive treatments of four weeks with placebo, spirapril (6 mg daily), or hydrochlorothiazide (HCT2) (24 mg daily). At the end of each treatment, blood samples for...... assessment of platelet aggregation and platelet release of platelet factor 4 (PF4) and for assessment of fibrinolysis, estimated by tissue plasminogen activator (t-PA), plasminogen activator inhibitor-type 1 (PAI-1), and euglobulin clot lysis time (ECLT), were taken, first at rest, then immediately after...... five to ten minutes of vigorous exercise, and finally after the subsequent hour of recovery rest. Platelet aggregation induced in vitro by adrenaline significantly decreased during treatment with HCT2, the threshold rising to 10 microM as compared with 1.0 with placebo (P <0.05) at rest, and the...

  14. Foreign Firms, Domestic Wages

    OpenAIRE

    Malchow-Møller, Nikolaj; Markusen, James R.; Schjerning, Bertel

    2013-01-01

    Many papers have documented a wage premium in foreign-owned and large firms. However, there is very little formal theory in the literature and empirical analyses are typically not based on hypotheses which are rigorously derived from theory. This paper contributes to the theory-empirics gap by developing a model that allows for two “pure” explanations for the wage premium. The first is a heterogenous-worker explanation along the lines of Yeaple (2005), where firms that select more scaleintens...

  15. Entrepreneurship and the Firm

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul; Klein, Peter G.

    12 chapters that all seek to advance the understanding of these issues by drawing on Austrian ideas. Building on existing research in transaction cost economics, agency theory, evolutionary economics and the resource-based theory of the firm, the authors cover a wide range of theoretical and applied......While characteristically "Austrian" themes such as entrepreneurship, economic calculation, tacit knowledge and the temporal structure of capital are clearly relevant to the business firm, Austrian economists have said relatively little about management, organization and strategy. This work features...

  16. Industry segment effects and firm effects on firm performance in single industry firms

    OpenAIRE

    Houthoofd, Noël; Hendrickx, Jef

    2012-01-01

    The purpose of the paper is to identify the sources of variation in firm performance. This is one of the cornerstones of strategy research, i.e. the relative importance of industry and firm level effects on firm performance. Multilevel analysis is well suited to analyze variance in performance when the data are hierarchically structured (industry segments consist of firms, firms operate within the context of industry segments). The Belgian industry studied is a service industry that consists ...

  17. Biological variation in tPA-induced plasma clot lysis time

    NARCIS (Netherlands)

    S. Talens (Simone); J.J.M.C. Malfliet (Joyce); G. Rudež (Goran); H.M.H. Spronk (Henri); N.A.H. Janssen (N. A H); P. Meijer (Piet); C. Kluft (Cornelius); M.P.M. de Maat (Moniek); D.C. Rijken (Dingeman)

    2012-01-01

    textabstractHypofibrinolysis is a risk factor for venous and arterial thrombosis, and can be assessed by using a turbidimetric tPA-induced clot lysis time (CLT) assay. Biological variation in clot lysis time may affect the interpretation and usefulness of CLT as a risk factor for thrombosis. Suffici

  18. 7 CFR 58.436 - Rennet, pepsin, other milk clotting enzymes and flavor enzymes.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436 Section 58.436 Agriculture Regulations of the Department of Agriculture (Continued... clotting enzymes and flavor enzymes. Enzyme preparations used in the manufacture of cheese shall be...

  19. The Multinational Firm

    DEFF Research Database (Denmark)

    Morgan, Glenn; Hull Kristensen, Peer; Whitley, Richard

    . These processes occur at a number of levels which are explored in different empirical settings. Firstly, at the level of governance, multinational firms may develop conflicts between investors from different national contexts, for example between the arms-length orientation of Anglo-Saxon institutional investors...

  20. Determinants of new firm success

    OpenAIRE

    Veronique A.J.M. Schutjens; Egbert Wever

    2000-01-01

    The differences between new firms, even the differences present right at the start, may affect their life course and success over time. This article addresses the determinants of success of Dutch start-ups from a longitudinal perspective. After an overview of the literature on both the definition of success and the success factors of new firms we test how new firm characteristics relate to firm growth in number of employees using a panel of nearly 2,000 firms. In addition to a large firm size...

  1. MEASURING INDUSTRY AND FIRM EFFECTS IN FOOD AND AGRIBUSINESS FIRMS

    OpenAIRE

    Schumacher, Sara K.; Boland, Michael A.

    2003-01-01

    Managers craft strategies that, if successfully implemented, can improve profitability and financial performance over time. Can firms repeat their performance over time? If so, then a manager who crafted a successful strategy could expect her/his firm to achieve greater profitability relative to other firms within its industry. The objective of this study was to compare business performance (accounting profitability) for publicly traded and cooperatively-owned food and agribusiness firms. We ...

  2. Corporate Ownership Structure and Firm Performance: Evidence from Greek Firms

    OpenAIRE

    Panayotis Kapopoulos; Sophia Lazaretou

    2006-01-01

    The Berle-Means thesis (1932) implies that diffuse ownership adversely affects firm performance. This paper tries to investigate whether there is strong evidence to support the notion that variations across firms in observed ownership structures result in systematic variations in observed firm performance. We test this hypothesis by assessing the impact of the structure of ownership on corporate performance, measured by profitability, using data for 175 Greek listed firms. Following Demsetz a...

  3. How Entrepreneurial Firms Prosper while Larger Firms Crumble

    Directory of Open Access Journals (Sweden)

    P. K. Shukla

    2009-02-01

    Full Text Available Many firms are facing great difficulty surviving the declining financial markets in Fall 2008. As larger firms take drastic measures to control and cut costs while forecasting declining revenue, entrepreneurial firms view the same marketplace in a more positive light. What separate these two types of firms is their differing levels of entrepreneurial intensity.An entrepreneurial grid positions firms upon two dimensions: Frequency of Entrepreneurship and Degree of Entrepreneurship (innovativeness, risk taking, and proactiveness. Just as managers select the placement of their firm on market dimensions such as quality and price, firms need to make a strategic position choice on where they wish their firm to be placed as related to entrepreneurial intensity. The firms listed in a recent article from BusinessWeek magazine titled “The World’s Most Innovative Companies” portrays a higher level of entrepreneurial efforts on both dimensions; firms that would be labeled as revolutionary on the entrepreneurial grid. It would be expected that as consumers expect new and improved products and services to emerge from innovative markets, firms labeled as periodic/incremental would have difficulties in sustaining continual growth. Additionally, firms labeled as continuous or incremental, dynamic, and periodic or discontinuous on the grid would be expected to have moderate success.

  4. The Innovative Capacity of Firms

    Directory of Open Access Journals (Sweden)

    Neely Andy

    2014-11-01

    Full Text Available Innovation is widely accepted as a crucial competitive weapon in today's global market place. Yet the levels of innovation achieved by different firms, even within the same industry, can vary widely. The key question raised by this observation is why. Why are some firms more innovative than others? What are the factors that determine a firm's capacity to innovate and how can these be managed to enhance the firm's innovative potential? This paper sets out to address these and related issues. It reports the results of a study of competitiveness and innovation of firms in the East of England. In the paper it is argued that the innovative capacity of a firm is a function of the firm's culture, resources, competences and networks. Justification for this framework is provided by a review of the relevant literature and a series of case studies examining the capacity to innovate of a sample of firms in the East of England.

  5. Fibrinolytic action on fresh human clots of whole body extracts and two semipurified fractions from Lonomia achelous caterpillar

    Directory of Open Access Journals (Sweden)

    Coll-Sangrona E.

    1998-01-01

    Full Text Available The severe bleeding diathesis produced by intoxication with the venom of Lonomia achelous caterpillars is characterized by prolonged bleeding from superficial skin wounds as well as massive hemorrhage into body cavities. The aim of the present study was to evaluate the effect of the crude venom and its fibrinolytic fractions on in vitro lysis of whole blood clots. Venom fractions with fibrinolytic activity were obtained by gel filtration chromatography on Sephadex G75 using imidazole buffer, pH 7.4, at a flow rate of 24 ml/h. Four peaks with fibrinolytic activity were obtained by this method. The highest activity was found in the first two peaks (both peaks were used for the experiments. The results show that the caterpillar venom degraded the preformed clots at a slower rate than plasmin. In addition, plasma protease inhibitors of the fibrinolytic system (a2-antiplasmin, a2-macroglobulin, PAI, etc. only weakly inhibited the lytic effect of the caterpillar venom. These characteristics, as well as the pattern of fibrinogen degradation products, the delay period on fibrin plate lysis and amidolytic activity on chromogenic substrate, reported previously, indicate that the caterpillar enzymes are different from plasmin and trypsin.

  6. Alternative theories of the firm

    OpenAIRE

    Staněk, Jan

    2014-01-01

    This thesis is focusing on alternative theories of the firm and their distinctions to the traditional neoclassical theory of profit maximization. It goes back to perception of the firm in the society and to development of theoretical concepts of the firm, as well as to different points of view of profit or satisfaction principle. You will learn more about the reason which triggered the beginnings of alternative theories of the firm like separation of ownership and control, which was one of th...

  7. Matching Firms, Managers, and Incentives

    OpenAIRE

    Bandiera, Oriana; Guiso, Luigi; Prat, Andrea; Sadun, Raffaella

    2009-01-01

    We provide evidence on the match between firms, managers and incentives using a new survey designed for this purpose. The survey contains information on a sample of executives’ risk preferences and human capital, on the explicit and implicit incentives they face and on the firms they work for. We model a market for managerial talent where both firms and managers are heterogeneous. Following the sources of heterogeneity observed in the data, we assume that firms differ by ownership structure a...

  8. Japanese firms in the EU.

    OpenAIRE

    Hamada, Y.

    2008-01-01

    The number of Japanese firms in Brussels has increased since the creation of the European Single Market. At the same time, large European firms have become independent political actors and harmonized their lobbying pattern, creating a distinctive business-government relationship in the EU. Yet, it still remains to be examined whether Japanese firms are able to utilize their political options and conform to the new EU lobbying style, which features firms' direct participation within the policy...

  9. Firm growth from a knowledge

    OpenAIRE

    Laursen, Keld

    2010-01-01

    Although there are several theories of growth of the firm, the literature is limited in two interrelated respects. First, empirical evidence does not match well theoretical predictions. Second, the firm growth literature does not address the structure of knowledge both in firms and sectors as well as knowledge flows between them. Based on existing theoretical and empirical literature, the paper outlines an ‘appreciative’ theory of firm growth and presents new testable hypothese...

  10. Board diversity in family firms

    OpenAIRE

    Menozzi, Anna; Fraquelli, Giovanni; Novara, Jolanda de

    2015-01-01

    The paper deals with diversity as a key factor to improve the board of directors’ decision process in family firms. The empirical literature about board diversity points at the positive impact of diversity on board functioning and firm performance. The paper uses a statistical diversity index to capture the heterogeneity of board of directors and put it in relation with firm performance, as measured by firm profitability. The empirical analysis is based on a newly collected panel of 327 famil...

  11. Market perception of firm strategy

    OpenAIRE

    Ozer Asdemir; Guy D. Fernando; Arindam Tripathy

    2013-01-01

    Purpose – Research has shown that firms successfully pursuing either a cost leadership or a differentiation strategy are better able to gain competitive advantages over other firms and accordingly achieve superior performance. Thus, if firms actually do realize superior performance based on their strategic orientation, capital markets should recognize this and place a positive value on such strategy-focused firms. The aim of this paper is to empirically investigate how capital markets perceiv...

  12. How to Assess Fibrinogen Levels and Fibrin Clot Properties in Clinical Practice?

    Science.gov (United States)

    Undas, Anetta

    2016-06-01

    Fibrin formed from fibrinogen is the main component of thrombi. Clot structure is characterized by fiber thickness and pore size, which differs within a given clot and between individuals. Plasma clot architecture is largely determined by the quantity and quality of fibrinogen. Plasma fibrinogen concentrations are most commonly measured in citrated plasma using the Clauss method. However, several factors, including instrument type and reagent, may affect results. Other approaches to express the ability of fibrinogen to clot involve prothrombin time-derived or clottable protein assays, while fibrinogen antigen levels in clinical settings are measured using immunological or precipitation assays. Fibrin clot permeability (reflected by the Darcy constant, K s) being proportional to a buffer volume percolating through a clot under a given hydrostatic pressure is now the most commonly used measure of clot structure. Low K s values indicating tightly packed fibrin structure have been shown to be associated with venous and arterial thrombotic complications, while high K s might contribute to bleeding disorders. The measurement of K s, however, is not standardized and validated. This review summarizes the current knowledge on practical aspects of the measurement of fibrinogen levels and K s in patients. PMID:27071050

  13. Belgian firms visiting CERN

    CERN Multimedia

    FP Department

    2009-01-01

    25 – 26 MAY 2009 09.00 to 17.00 Monday 25 May 09.00 to 17.00 Tuesday 26 May Individual interviews will take place in technicians’ offices. The firms will contact relevant users/technicians but any user wishing to make contact with a particular firm is welcome to use the contact details which are available from each departmental secretariat or from the GS Department web pages here. List of Companies:Automation Services and Consulting BVBA Burrick NV, (PLC) Cissoid DB Engineering Design, Drafting & Services BVBA Entelec Control Systems GILLAM-Fei S.A. HPC ICSENSE IWT – Enterprise Europe Flanders Jema SA Mecasoft SA SA Polmans Rapid-Torc Resarm Engineering Plastics SA Sentera Europa NV SLC BVBA Stocker Industrie SA Technord Tecnubel Winlock BVBA For further information please contact Caroline Laignel (GS-DI 73722) or Karine Robert (GS-SEM-LS 74407).

  14. Inside the Family Firm

    OpenAIRE

    Bennedsen, Morten; Nielsen, Kasper; Pérez-González, Francisco; Wolfenzon, Daniel

    2005-01-01

    This paper uses a unique dataset from Denmark to investigate (1) the role of family characteristics in corporate decision making, and (2) the consequences of these decisions on firm performance. We focus on the decision to appoint either a family or an external chief executive officer (CEO). We show that a departing CEO’s family characteristics have a strong predictive power in explaining CEO succession decisions: family CEOs are more frequently selected the larger the size of the family, the...

  15. Foreign Firms Partner Up

    Institute of Scientific and Technical Information of China (English)

    DAVID HENDRICKSON

    2006-01-01

    @@ There is an important strategic adjustment occurring on the part of foreign dairy companies seeking to capitalize on the China market. Rather than going it alone,with local partnerships little more than an entry mechanism,global giants such as Danone,Arla, and Fonterra are taking advantage of the country's more relaxed foreign investment rules by upping their stakes in established local firms and expanding the role they play in business and industrial operations.

  16. Socially Responsible Firms

    OpenAIRE

    Renneboog, L.D.R.; Liang, H; Ferrell, A.

    2014-01-01

    In the corporate finance tradition starting with Berle & Means (1923), corporations should generally be run so as to maximize shareholder value. The agency view of corporate social responsibility (CSR) generally considers CSR as a managerial agency problem and a waste of corporate resources, since corporate insiders do good with other people’s money. We evaluate this agency view using large-scale datasets with global coverage (59 countries) on firm-level corporate engagement and compliance wi...

  17. Financial Frictions and Firm Dynamics

    OpenAIRE

    Paul Bergin; Ling Feng; Ching-Yi Lin

    2014-01-01

    Firm entry dynamics are an integral part of the propagation of financial shocks to the real economy. A VAR documents that adverse financial shocks in the U.S. postwar period are associated with a fall in new firm creation and a fall in firm equity values. We propose a DSGE model with endogenous firm entry and financial frictions that is able to explain these facts. The model is novel in giving firms a choice of financing up-front entry costs through a combination of debt as well as equity, so...

  18. Power Law in Firms Bankruptcy

    CERN Document Server

    Hong, B H; Lee, J W; Hong, Byoung Hee; Lee, Kyoung Eun; Lee, Jae Woo

    2007-01-01

    We consider the scaling behaviors for fluctuations of the number of Korean firms bankrupted in the period from August 1 2002 to October 28 2003. We observe a power law for the distribution of the number of the bankrupted firms. The Pareto exponent is close to unity. We also consider the daily increments of the number of firms bankrupted. The probability distribution of the daily increments for the firms bankrupted follows the Gaussian distribution in central part and has a fat tail. The tail parts of the probability distribution of the daily increments for the firms bankrupted follow a power law.

  19. Power law in firms bankruptcy

    Science.gov (United States)

    Hong, Byoung Hee; Lee, Kyoung Eun; Lee, Jae Woo

    2007-01-01

    We consider the scaling behaviors for fluctuations of the number of Korean firms bankrupted in the period from 1 August 2002 to 28 October 2003. We observe a power law for the distribution of the number of the bankrupted firms. The Pareto exponent is close to unity. We also consider the daily increments of the number of firms bankrupted. The probability distribution of the daily increments for the firms bankrupted follows the Gaussian distribution in central part and has a fat tail. The tail parts of the probability distribution of the daily increments for the firms bankrupted follow a power law.

  20. Time-dependent low-field MRI characteristics of canine blood: an in vitro study.

    Science.gov (United States)

    Jeong, Jimo; Park, Sangjun; Jeong, Eunseok; Kim, Namsoo; Kim, Minsu; Jung, Yechan; Cho, Youngkwon; Lee, Kichang

    2016-03-01

    This study was conducted to assess time-sensitive magnetic resonance (MR) changes in canine blood using low-field MR. Arterial and venous blood samples were collected from eight healthy beagle dogs. Samples were placed in 5-mL tubes and imaged within 3 hours of collection at 1 day intervals from day 1 to day 30. The following sequences were used: T1-weighted (T1W), T2-weighted (T2W), fluid-attenuated inversion recovery (FLAIR), short tau inversion recovery (STIR), and T2-star gradient-echo (T2(*)-GRE). Visual comparison of the images revealed that four relatively homogenous blood clots and twelve heterogeneous blood clots developed. The margination of the clot and plasma changed significantly on day 2 and day 13. On day 2, heterogeneous blood clots were differentiated into 2 to 3 signal layers in the T2W, T1W, and especially the STIR images. Hypointense signal layers were also detected in the blood clots in STIR images, which have T2 hypo, FLAIR hypo, and T1 hyper intense signals. In all images, these signal layers remained relatively unchanged until day 13. Overall, the results suggest that hematomas are complex on low-field MRI. Accordingly, it may not be feasible to accurately characterize hemorrhages and predict clot age based on low-field MRI. PMID:27051346

  1. Blood composition of the reindeer . II. Blood chemistry

    OpenAIRE

    Mauri Nieminen; Jouni Timisjärvi

    1983-01-01

    The blood chemical composition of 578 semi-domestic reindeer were investigated in respect to age, season, calving and nutrition in Northern Finland during 1973-79. The weight gain was maximally 400 g/day at an age of 4-8 weeks as also reflected by high serum thyroxine (T4), alkaline phosphatase (SAP), creatine phosphokinase (CPK) and blood glucose values. Low SAP activity in winter indicated a cessation of growth. The pH of the venous blood was 7.35 and the clotting activity very high (21 sec...

  2. Multifrequency acoustics as a probe of mesoscopic blood coagulation dynamics

    Science.gov (United States)

    Ganesan, Adarsh; Rajendran, Gokulnath; Ercole, Ari; Seshia, Ashwin

    2016-08-01

    Coagulation is a complex enzymatic polymerisation cascade. Disordered coagulation is common in medicine and may be life-threatening yet clinical assays are typically bulky and/or provide an incomplete picture of clot mechanical evolution. We present the adaptation of an in-plane acoustic wave device: quartz crystal microbalance with dissipation at multiple harmonics to determine the time-evolution of mesoscale mechanical properties of clot formation in vitro. This approach is sensitive to changes in surface and bulk clot structure in various models of induced coagulopathy. Furthermore, we are able to show that clot formation at surfaces has different kinetics and mechanical strength to that in the bulk, which may have implications for the design of bioprosthetic materials. The "Multifrequency acoustics" approach thus enables unique capability to portray biological processes concerning blood coagulation.

  3. Could a Clot-Busting Drug Help Treat a 'Bleeding' Stroke?

    Science.gov (United States)

    ... a Clot-Busting Drug Help Treat a 'Bleeding' Stroke? Two studies suggest that tPA infusion to brain ... tPA might help patients suffering a hemorrhagic ("bleeding") stroke. According to the American Stroke Association, only about ...

  4. Measuring Firm Performance

    DEFF Research Database (Denmark)

    Assaf, A. George; Josiassen, Alexander; Gillen, David

    2014-01-01

    Set in the airport industry, this paper measures firm performance using both desirable and bad outputs (i.e. airport delays). We first estimate a model that does not include the bad outputs and then a model that includes bad outputs. The results show important differences in the efficiency and...... productivity results depending on whether bad outputs are or are not included in the model. The differences reflect the resource cost to society and the potential cost to an airport if such externalities were internalized. Finally, the paper provides measures of shadow prices for the bad output, in our case...

  5. Thromboelastography to Monitor Clotting/Bleeding Complications in Patients Treated with the Molecular Adsorbent Recirculating System

    OpenAIRE

    Schuepbach, Reto A; Renner, Eberhard L; Beat Müllhaupt; Marco Maggiorini; Markus Béchir; Stover, John F.; Reto Stocker; Jörg Bösiger; Bachli, Esther B.

    2011-01-01

    Background. The Molecular Adsorbent Recirculating System (MARS) has been shown to clear albumin-bound toxins from patients with liver failure but might cause bleeding complications potentially obscuring survival benefits. We hypothesized that monitoring clotting parameters and bed-side thromboelastography allows to reduce bleeding complications. Methods. Retrospective analysis of 25 MARS sessions during which clotting parameters were monitored by a standardized protocol. Results. During MARS ...

  6. Corporate Governance and Firm Performance: Results from Greek Firms

    OpenAIRE

    Toudas, Kanellos; Karathanassis, George

    2007-01-01

    In this paper, we construct a Governance Index for a sample of Greek companies quoted on the Athens Stock Exchange. We then classify firms, using each firm governance index, into three governance portfolios. Furthermore, the Fama and French model, extended to include a momentum variable, is tested for each of the three governance portfolios. Our findings suggest that most of the firms in our sample are semi-democracies followed by democracies and dictatorships respectively. Good governance ap...

  7. T2* "susceptibility vessel sign" demonstrates clot location and length in acute ischemic stroke.

    Directory of Open Access Journals (Sweden)

    Olivier Naggara

    Full Text Available OBJECTIVES: The aim of our study was to evaluate, in acute ischemic stroke patients, the diagnostic accuracy of the MRI susceptibility vessel sign (SVS against catheter angiography (DSA for the detection of the clot and its value in predicting clot location and length. MATERIALS AND METHODS: We identified consecutive patients (2006-2012 admitted to our center, where 1.5 T MRI is systematically implemented as first-line diagnostic work-up, with: (1 pre-treatment 6-mm-thick multislice 2D T2* sequence; (2 delay from MRI-to-DSA 94%. Inter- and intra-observer ICC was excellent for clot length as measured on T2* (ĸ ≥ 0.97 and as measured on DSA (ĸ ≥ 0.94. Correlation between T2* and DSA for clot length was excellent (ICC: 0.88, 95%CI: 0.81-0.92; Bland & Altman: mean bias of 1.6% [95%CI: -4.7 to 7.8%], Passing & Bablok: 0.91. CONCLUSIONS: SVS is a specific marker of clot location in the anterior and posterior circulation. Clot length greater than 6 mm can be reliably measured on T2*.

  8. Firm Level Determinants of Investment in the Kenyan Manufacturing Firm

    Directory of Open Access Journals (Sweden)

    Augustus S. Muluvi

    2011-09-01

    Full Text Available This study uses firm level data to investigate the investment behavior in the Kenyan manufacturing firms. Using Probit and Tobit regression models the results shows that factors determining the decision to invest are different from those determining the share invested. Overall the results shows low levels of investment by Kenyan manufacturing firms and the importance of firm level data in explaining the investment behavior. On the policy front the paper observes the role of government in the provision of stable macroeconomic policies, affordable credit and basic infrastructure in order to attract investment in this sector.

  9. Family firms, share liquidity, and the effect on firm value

    OpenAIRE

    Laihomäki, Maija

    2010-01-01

    The main objective of this master’s thesis is to discover how the share liquidity of family firms affects firm value. First I investigate the impact concentrated ownership has on firm performance. After that I heighten my investigation and take share liquidity into account. The first half of this master’s thesis discusses the comparisons between the performance of family and non-family firms according to existing literature. I present the results of previous studies about family firm’s pe...

  10. Firms and gender: performance differentials between male and female firms

    OpenAIRE

    Domenico Depalo; Francesca Lotti

    2013-01-01

    Many empirical analyses find that the performance of firms headed by women (female firms) varies with respect to those headed by men and that the greatest part of this gap is due to observable characteristics (i.e. gender) related to firms� characteristics. In this paper we evaluate whether this finding also holds for Italy in terms of productivity and returns.The classification of firms by gender follows that prescribed in Law 215/92; for the purposes of this paper only partnerships and pr...

  11. Danish firms visit CERN

    CERN Multimedia

    FP Department

    2011-01-01

    30 – 31 JANUARY 2012 09:00 to 17:00 Monday 30 January 09:00 to 17:00 Tuesday 31 January Individual interviews will take place in technicians’ offices. The firms will contact relevant users/technicians but any user wishing to make contact with a particular firm is welcome to use the contact details available from the secretariat of their department or from the GS Department web page. List of Companies: · Axcon APS · BB Electronics A/S · B.Rustfrit Stal A/S · CIM Industrial Systems A/S · Danfysik A/S · Develco A/S · Eletronic A/S · GPV Group · Innoware A/S · JLI Vision A/S · NECAS A/S· NKT Cables A/S · Noliac A/S · Prodan A/S · Röttger’s Vaerktoj A/S · Vengcon APS For further information please contact Claudia Bruggmann Furlan  GS-IS-LS 73312 or Caroline Laignel GS-DI 73722.

  12. Lead Directorship and Firm Performance

    OpenAIRE

    OuYang, Bo

    2013-01-01

    This paper empirically explores the role of the lead directors in the corporate governance system and strives to empirically examine the association between the lead directorship and firm performance. I measure firm performance by three empirical proxies: Tobin’s Q, returns on assets (ROA) and stock returns. I explore the research question on the relationship between lead directorship and firm performance in both cross-sectional and inter-temporal contexts. The sample consists of S & P 500 fi...

  13. Controlling Shareholders and Firm Value

    OpenAIRE

    Borja Larraín; Matías Tapia

    2012-01-01

    We study the relationship between firm value and ownership concentration in a market where firms are controlled by large shareholders. We set up an equilibrium model with private benefits of control and bargaining between large shareholders. With simulated data from the model we are able to match approximately the value-concentration relationship observed among Chilean firms in 1990-2009. The model also delivers novel predictions regarding the relationship between investor protection and: (1)...

  14. Firm turnover and inflation dynamics

    OpenAIRE

    Lenno Uusküla

    2015-01-01

    This paper examines the role of firm turnover in explaining inflation dynamics. I augment a New-Keynesian DSGE model with endogenous entry and exogenous stochastic exit and estimate with the Bayesian full information approach for the US economy. Results show that shocks to the entry cost explain more than half of the inflation variance at the business cycle frequencies. When it is cheap to create firms, the number of new firms goes up and inflation increases as labour intensive creation of fi...

  15. Should firms employ personalized pricing?

    OpenAIRE

    Matsumura, Toshihiro; Matsushima, Noriaki

    2013-01-01

    The recent developments in information technology (IT) have enabled firms to employ personalized pricing. Should all firms employ personalized pricing even though the adaptation costs of such pricing strategies are not high? This paper theoretically demonstrates a situation in which all firms do not always employ personalized pricing even though the fixed costs to do so is zero. The model is based on those of Thisse and Vives (1988) and Shaffer and Zhang (2002). Our model incorporates the fac...

  16. Director Characteristics and Firm Performance

    OpenAIRE

    Gantenbein, Pascal; Volonté, Christophe

    2011-01-01

    The traditional methodology examining optimal boards relates a simple board variable (e.g., independence or board demography) to firm performance, however, ig- noring other board characteristics. This paper investigates how the education and business experience of directors affect firm performance. The sample consists of 1,574 directorships from 224 listed firms in Switzerland. Using OLS and including control variables, the results show that graduates of minor Swiss universities are negativel...

  17. Exploring Marketing in Micro Firms

    OpenAIRE

    WÀgar, Karolina; Björk, Peter; Ravald, Annika; West, Björn

    2007-01-01

    Purpose - The purpose of the paper is to explore the practice of marketing in micro firms. Which are the challenges micro firms encounter and how do they handle them? Methodology - The research methodology is based on the theory-in-use approach (Zaltman, Heffring & LeMasters 1982) in order to inductively explore the practice of marketing in micro firms. The empirical findings rest on ten case studies, where data has been generated through repeated interactions with each case. Find...

  18. The Dynamics of Firm Lobbying

    OpenAIRE

    Kerr, William Robert; William F. Lincoln; Mishra, Prachi

    2014-01-01

    We study the determinants of the dynamics of firm lobbying behavior using a panel data set covering 1998-2006. Our data exhibit three striking facts: (i) few firms lobby, (ii) lobbying status is strongly associated with firm size, and (iii) lobbying status is highly persistent over time. Estimating a model of a firm's decision to engage in lobbying, we find significant evidence that up-front costs associated with entering the political process help explain all three facts. We then exploit a n...

  19. Zipf law in firms bankruptcy

    Science.gov (United States)

    Fujiwara, Yoshi

    2004-06-01

    Using an exhaustive list of Japanese bankruptcy in 1997, we discover a Zipf law for the distribution of total liabilities of bankrupted firms in high debt range. The life-time of these bankrupted firms has exponential distribution in correlation with entry rate of new firms. We also show that the debt and size are highly correlated, so the Zipf law holds consistently with that for size distribution. In an attempt to understand “physics” of bankruptcy, we show that a model of debtor-creditor dynamics of firms and a bank, recently proposed by economists, can reproduce these phenomenological findings.

  20. Determinants of Capital Structure in Family Firms

    OpenAIRE

    Akbarali, Ahmed; Foma, Awambeng

    2015-01-01

    Most firms are using optimal combination of equity and debt so as to maximize firms value and the wealth of the shareholders. To achieve all these, firms should be aware of the factors that influence the capital structure decisions. Previous empirical studies attempted to explain what determines the choice of capital structure in firms. The focus was on firms in general without categorizing family firms and non-family firms. The primary objective of this study is to examine what determines th...

  1. Stakeholder Governance, Competition and Firm Value

    OpenAIRE

    Allen, Franklin; Carletti, Elena; Marquez, Robert

    2014-01-01

    In many countries, the legal system or social norms ensure that firms are stakeholder oriented. We analyze the advantages and disadvantages of stakeholder-oriented firms that are concerned with employees and suppliers compared to shareholder-oriented firms in a model of imperfect competition. Stakeholder firms are more (less) valuable than shareholder firms when marginal cost uncertainty is greater (less) than demand uncertainty. With globalization shareholder firms and stakeholder firms ofte...

  2. Risk-taking and Firm Growth

    OpenAIRE

    Xu, Peng

    2015-01-01

    Using firm data from 2002-2012, we examine the relationship between capital structure and risk taking, and between risk taking and firm performance of small and medium-sized enterprises and large private firms. Domestically-owned entrepreneurial private firms are more risk averse than domestically-owned affiliated private firms. Foreign-owned affiliated private firms are much more risk taking than domestically-owned private firms. However, leverage is not strongly associated with less corpora...

  3. Patenting activities and firm performance : Does firm size matter?

    NARCIS (Netherlands)

    Andries, P.; Faems, D.L.M.

    2013-01-01

    Whereas prior research has provided valuable insights into the willingness of small and medium-sized enterprises (SMEs) and large firms to engage in patenting, a comparison of the performance implications of patenting activities across small and large firms is still lacking. This gap is important be

  4. Scientific Auditing Firms

    CERN Document Server

    Sarma, Gopal P

    2016-01-01

    The "crisis of reproducibility" has been a significant source of controversy, heated debate, and calls for reform to institutional science in recent years. As a long-term solution to address both the present crisis and future obstacles, I propose the creation of a new form of research organization whose purpose would be to conduct random audits of the scientific literature. I suggest that data analytics of a digitized scientific corpus may play a critical role in allowing broadly educated scientists to identify linchpin results to investigate in further detail across all disciplines. I argue that a simple "mock" trial run of a simplified auditing firm consisting of several researchers over a short time period would provide valuable insight into the feasibility of this proposal.

  5. Belgian Firms Visit CERN

    CERN Multimedia

    2001-01-01

    Fifteen Belgian firms visited CERN last 2 and 3 April to present their know-how. Industrial sectors ranging from precision machining to electrical engineering and electronics were represented. And for the first time, companies from the Flemish and Brussels regions of the country joined their Walloon compatriots, who have come to CERN before. The visit was organised by Mr J.-M. Warêgne, economic and commercial attaché at the Belgian permanent mission for the French-speaking region, Mr J. Van de Vondel, his opposite number for the Flemish region, and Mrs E. Solowianiuk, economic and commercial counsellor at the Belgian permanent mission for the Brussels-Capital region.

  6. Highly Effective DNA Extraction Method from Fresh, Frozen, Dried and Clotted Blood Samples

    OpenAIRE

    Jaleh Barar; Sina Atashpaz; Abolfazl Barzegari; Vala Kafil; Sepideh Zununi Vahed; Farzaneh Soltanzad; Sara Samadi Shams

    2011-01-01

    Introduction: Today, with the tremendous potential of genomics and other recent advances in science, the role of science to improve reliable DNA extraction methods is more relevant than ever before. The ideal process for genomic DNA extraction demands high quantities of pure, integral and intact genomic DNA (gDNA) from the sample with minimal co-extraction of inhibitors of downstream processes. Here, we report the development of a very rapid, less-hazardous, and high throughput protocol for e...

  7. Activation of blood clotting and fibrinolysis in angiocardiography with ionic and non-ionic contrast medium

    International Nuclear Information System (INIS)

    Purpose: To study the effects of a ionic (amidotrizoate) and a nonionic X-ray contrast medium (iopromid) during routine levocardiography and coronary angiography, we employed assays that detect reaction products of thrombin and plasmin to assess the activation of the haemostatic system. Methods: Subsequent to informed consent, 20 patients were randomly assigned to receive either amidotrizoate or iopromid during standard levocardiography and coronary angiography in a double-blind comparative study. Groups were comparable in respect of age, weight, sex and severity of the disease. No anticoagulation was provided. Coronary angiography was performed according to a standardised protocol. Consumption of contrast media and duration of the examination were comparable in both groups. Results: Thrombin generation (F.1+2) and thrombin activity (TAT) were higher with the ionic contrast medium but did not attain statistical significance. Fibrin generation and degradation as expressed by D-dimer fibrin split products was significantly increased in patients who had been receiving amidotrizoate (p<0,05, U-Test). Conclusion: The non-ionic X-ray contrast medium induced significantly less haemostatic activation in vivo than did the ionic medium amidotrizoate. These data suggest that earlier in vitro observations of more pronounced anticoagulant effects of ionic X-ray contrast media are of limited significance for the evaluation of in vivo effects of X-ray contrast media on haemostatic function. (orig.)

  8. A feasible strategy for preventing blood clots in critically ill patients with acute kidney injury (FBI)

    DEFF Research Database (Denmark)

    Robinson, Sian; Zincuk, Aleksander; Larsen, Ulla Lei;

    2014-01-01

    BACKGROUND: Previous pharmacokinetic trials suggested that 40 mg subcutaneous enoxaparin once daily provided inadequate thromboprophylaxis for intensive care unit patients. Critically ill patients with acute kidney injury are at increased risk of venous thromboembolism and yet are often excluded...... from these trials. We hypothesized that for critically ill patients with acute kidney injury receiving continuous renal replacement therapy, a dose of 1 mg/kg enoxaparin subcutaneously once daily would improve thromboprophylaxis without increasing the risk of bleeding. In addition, we seek to utilize...... assign eligible critically ill adults with acute kidney injury into a treatment (1 mg/kg enoxaparin subcutaneously once daily) or control arm (40 mg enoxaparin subcutaneously once daily) upon commencement of continuous renal replacement therapy.We calculated that with 133 patients in each group, the...

  9. Women with Polycystic Ovary Syndrome Taking Combined Oral Contraceptives Have Greater Risk of Blood Clots

    Science.gov (United States)

    ... Opportunities Announcement Guidance AHRQ Grants Policy Notices AHRQ Informed Consent & Authorization Toolkit for Minimal Risk Research HHS Grants ... is not used according to clinical guidelines Lower consent rates for organ donation found ... Nursing Home Compare, most nursing home selections were made ...

  10. Firm Traits and Web Based Disclosures in Top Nigerian Firms

    Directory of Open Access Journals (Sweden)

    Bello Ayuba

    2016-02-01

    Full Text Available The use of the internet as a medium of dissemination of information to stakeholders is increasingly gaining grounds. This study extends existing literature on web disclosures by investigating the characteristics that predict the extent of web-based disclosures. In this study, corporate websites of top Nigerian firms are used as sources of data, while a regression analysis is employed to examine the extent of prediction. Results indicate that the firm size and industry type are significant determinants of web disclosures. However, other firm traits such as ownership dispersion and financial performance do not significantly explain the extent of internet disclosures. The study recommends that a regulatory template for corporate web disclosures be put in place by government regardless of the size or industry classification of the firm. This is with a view to considerably reduce agency conflicts arising from information asymmetry in publicly listed firms in Nigeria.

  11. Firm-Specific Learning and the Nature of the Firm

    DEFF Research Database (Denmark)

    Knudsen, Thorbjørn

    2007-01-01

    This article discusses the limits of a purely transaction cost explanation of the existence of the firm by pointing to additional factors. A simple heuristic model shows that firm-specific learning effects can overcome the costs of monitoring employees, and explain the existence of the firm even in...... the absence of transaction costs related to the market mode of organisation. Comparing the relative importance of transaction cost and capabilities explanations for the existence of the firm, there is no a priori reason to assume the supremacy of one type of explanation over the other. We argue that a...... conjoint research program, encompassing both transaction costs and capabilities, must be developed and tested empirically. Cet article discute les limites d'une explication de l'existence de la firme fondée exclusivement sur les coûts de transaction en indiquant quelques facteurs additionnels susceptibles...

  12. Quality control in audit firm

    OpenAIRE

    Dostálová, Milena

    2008-01-01

    Thesis deals with the quality control of audit firms in accordance with international regulations. Defining the requirements for quality based on the Code of Ethics and the International quality standard ISQC1. Part of this work is the practical demonstration of ISQC1 in the smaller audit firm. For comparison, there is a description of quality control in the U.S.

  13. Whom do new firms hire?

    DEFF Research Database (Denmark)

    2015-01-01

    Using the matched employer-employee data set for Denmark and information on the founders of new firms, we analyze the hiring choices of all new firms that entered from 2003 to 2010. We develop a theoretical model in which the quality of a firm’s employees determines its average cost, a firm’s pro...

  14. Competitive Advantage of Interconnected Firms

    DEFF Research Database (Denmark)

    Nell, Phillip Christopher; Andersson, Ulf

    We model the complex interplay between firm-level variables, notably capabilities and performance, and relationship-level variables: relationship-specific assets and network context. We test how the network context of individual exchange relationships as well as firm-level capabilities jointly af...

  15. How Firms Make Boundary Decisions

    DEFF Research Database (Denmark)

    Dobrajska, Magdalena; Billinger, Stephan; Becker, Markus

    2014-01-01

    We report findings from an analysis of 234 firm boundary decisions that a manufacturing firm has made during a 10 year period. Extensive interviews with all major decision makers located both at the headquarters and subsidiaries allow us to examine (a) who was involved in each boundary decision...

  16. Dividend Policy of German Firms

    NARCIS (Netherlands)

    Goergen, M.; Renneboog, L.D.R.; Correia Da Silva, L.

    2004-01-01

    German firms pay out a lower proportion of their cash flows than UK and US firms.However, on a published profits basis, the pattern is reversed.Company law provisions and accounting policies account for these conflicting results.A partial adjustment model is used to estimate the implicit target payo

  17. Does internationalization foster firm performance?

    NARCIS (Netherlands)

    van den Berg, Marcel

    2014-01-01

    The research in this dissertation concerns the impact of internationalization of business activities on several dimensions of firm performance. We show that the productivity ranking by trade status of Dutch manufacturing firms in increasing order of productivity is: non-traders, importers, exporters

  18. The spider hemolymph clot proteome reveals high concentrations of hemocyanin and von Willebrand factor-like proteins.

    Science.gov (United States)

    Sanggaard, Kristian W; Dyrlund, Thomas F; Bechsgaard, Jesper S; Scavenius, Carsten; Wang, Tobias; Bilde, Trine; Enghild, Jan J

    2016-02-01

    Arthropods include chelicerates, crustaceans, and insects that all have open circulation systems and thus require different properties of their coagulation system than vertebrates. Although the clotting reaction in the chelicerate horseshoe crab (Family: Limulidae) has been described in details, the overall protein composition of the resulting clot has not been analyzed for any of the chelicerates. The largest class among the chelicerates is the arachnids, which includes spiders, ticks, mites, and scorpions. Here, we use a mass spectrometry-based approach to characterize the spider hemolymph clot proteome from the Brazilian whiteknee tarantula, Acanthoscurria geniculata. We focused on the insoluble part of the clot and demonstrated high concentrations of proteins homologous to the hemostasis-related and multimerization-prone von Willebrand factor. These proteins, which include hemolectins and vitellogenin homologous, were previously identified as essential components of the hemolymph clot in crustaceans and insects. Their presence in the spider hemolymph clot suggests that the origin of these proteins' function in coagulation predates the split between chelicerates and mandibulata. The clot proteome reveals that the major proteinaceous component is the oxygen-transporting and phenoloxidase-displaying abundant hemolymph protein hemocyanin, suggesting that this protein also plays a role in clot biology. Furthermore, quantification of the peptidome after coagulation revealed the simultaneous activation of both the innate immune system and the coagulation system. In general, many of the identified clot-proteins are related to the innate immune system, and our results support the previously suggested crosstalk between immunity and coagulation in arthropods. PMID:26621385

  19. In Vitro impairment of whole blood coagulation and platelet function by hypertonic saline hydroxyethyl starch

    Directory of Open Access Journals (Sweden)

    Görlinger Klaus

    2011-02-01

    Full Text Available Abstract Background Hypertonic saline hydroxyethyl starch (HH has been recommended for first line treatment of hemorrhagic shock. Its effects on coagulation are unclear. We studied in vitro effects of HH dilution on whole blood coagulation and platelet function. Furthermore 7.2% hypertonic saline, 6% hydroxyethylstarch (as ingredients of HH, and 0.9% saline solution (as control were tested in comparable dilutions to estimate specific component effects of HH on coagulation. Methods The study was designed as experimental non-randomized comparative in vitro study. Following institutional review board approval and informed consent blood samples were taken from 10 healthy volunteers and diluted in vitro with either HH (HyperHaes®, Fresenius Kabi, Germany, hypertonic saline (HT, 7.2% NaCl, hydroxyethylstarch (HS, HAES6%, Fresenius Kabi, Germany or NaCl 0.9% (ISO in a proportion of 5%, 10%, 20% and 40%. Coagulation was studied in whole blood by rotation thrombelastometry (ROTEM after thromboplastin activation without (ExTEM and with inhibition of thrombocyte function by cytochalasin D (FibTEM, the latter was performed to determine fibrin polymerisation alone. Values are expressed as maximal clot firmness (MCF, [mm] and clotting time (CT, [s]. Platelet aggregation was determined by impedance aggregrometry (Multiplate after activation with thrombin receptor-activating peptide 6 (TRAP and quantified by the area under the aggregation curve (AUC [aggregation units (AU/min]. Scanning electron microscopy was performed to evaluate HyperHaes induced cell shape changes of thrombocytes. Statistics: 2-way ANOVA for repeated measurements, Bonferroni post hoc test, p Results Dilution impaired whole blood coagulation and thrombocyte aggregation in all dilutions in a dose dependent fashion. In contrast to dilution with ISO and HS, respectively, dilution with HH as well as HT almost abolished coagulation (MCFExTEM from 57.3 ± 4.9 mm (native to 1.7 ± 2.2 mm (HH 40

  20. Firm-specific learning and the investment behavior of large and small firms

    OpenAIRE

    Wenli Li; Weinberg, John A.

    1999-01-01

    We examine a model of the size distribution and growth of firms whereby firms learn about idiosyncratic productivity parameters. Aggregate shocks, by adding noise to learning at the firm level, can produce differentiated response across firms with their reactions depending on the position of the firms in their individual life cycle. In particular, young firms, which are smaller on average than older firms, can 'overreact' to aggregate shocks. Such differences across firm sizes and ages, which...

  1. Does Corporate Culture Matter for Firm Policies?

    OpenAIRE

    Cronqvist, Henrik; Low, Angie; Nilsson, Mattias

    2007-01-01

    Economic theories suggest that a firm's corporate culture matters for its policy choices. We construct a parent-spinoff firm panel dataset that allows us to identify culture effects in firm policies from behavior that is inherited by a spinoff firm from its parent after the firms split up. We find positive and significant relations between spinoff firms' and their parents' choices of investment, financial, and operational policies. Consistent with predictions from economic theories of corpora...

  2. The Role of Firm Ownership on Internationalization

    DEFF Research Database (Denmark)

    Hobdari, Bersant; Gregoric, Aleksandra; Sinani, Evis

    2011-01-01

    This paper investigates how different types of owners influence the extent of firm internationalization, measured by the share of firm exports in total sales. The results of the analysis carried out using firm level data of Estonian and Slovenian firms, show that the firms under the control of the...... internationalization process. Finally, high market share also leads to increased internationalization through exports as firms seek to expand in foreign markets after having dominated the domestic ones....

  3. Equilibrium labour turnover, firm growth and unemployment

    OpenAIRE

    Coles, Melvyn G; Dale T. Mortensen

    2012-01-01

    This paper identifies a data-consistent, equilibrium model of unemployment, wage dispersion, quit turnover and firm growth dynamics. In a separating equilibrium, more productive firms signal their type by paying strictly higher wages in every state of the market. Workers optimally quit to firms paying a higher wage and so move effciently from less to more productive firms. Start-up firms are initially small and grow endogenously over time. Consistent with Gibrat's law, individual firm growth ...

  4. Public/private transitions and firm financing

    OpenAIRE

    Huynh, Kim P.; Paligorova, Teodora; Petrunia, Robert

    2013-01-01

    A large body of empirical literature investigates differences in financing structures across firms. Private firms' financing receives little attention due to the lack of data. Using administrative confidential data on the universe of Canadian corporate firms, we compare financing relationships for private and public firms. Leverage ratios are lower for public firms and the difference is almost entirely driven by private firms' stronger reliance on short-term debt. We also find that private an...

  5. Stakeholder capitalism, corporate governance and firm value

    OpenAIRE

    Allen, Franklin; Carletti, Elena; Marquez, Robert

    2007-01-01

    We consider the advantages and disadvantages of stakeholder-oriented firms that are concerned with employees and suppliers as well as shareholders compared to shareholder-oriented firms. Societies with stakeholder-oriented firms have higher prices, lower output, and can have greater firm value than shareholder-oriented societies. In some circumstances, firms may voluntarily choose to be stakeholder-oriented because this increases their value. Consumers that prefer to buy from stakeholder firm...

  6. New Firm Growth: Exploring Processes and Paths

    OpenAIRE

    Garnsey, E.; Stam, Erik; Heffernan, P.; Hugo, O.

    2003-01-01

    textabstractThis paper provides a new methodology for the diachronic study of new firm growth, theoretically grounded in the work of Penrose (1995). We show that a model of firm growth as an unfolding process makes possible draw simple, measurable inferences from firm level to aggregate evidence on growth paths of new firms, expressed as propositions. Metrics on growth paths of new firms in three longitudinal samples of new firms are examined for evidence at the aggregate level consistent wit...

  7. Firm Sustainability Performance Index Modeling

    Directory of Open Access Journals (Sweden)

    Che Wan Jasimah Bt Wan Mohamed Radzi

    2015-12-01

    Full Text Available The main objective of this paper is to bring a model for firm sustainability performance index by applying both classical and Bayesian structural equation modeling (parametric and semi-parametric modeling. Both techniques are considered to the research data collected based on a survey directed to the China, Taiwan, and Malaysia food manufacturing industry. For estimating firm sustainability performance index we consider three main indicators include knowledge management, organizational learning, and business strategy. Based on the both Bayesian and classical methodology, we confirmed that knowledge management and business strategy have significant impact on firm sustainability performance index.

  8. Dividend Policy of German Firms

    OpenAIRE

    M. Goergen; Renneboog, L.D.R.; Correia Da Silva, L.

    2004-01-01

    German firms pay out a lower proportion of their cash flows than UK and US firms.However, on a published profits basis, the pattern is reversed.Company law provisions and accounting policies account for these conflicting results.A partial adjustment model is used to estimate the implicit target payout ratio and the speed of adjustment of dividends towards a long run target payout ratio. We find that German firms do not base their dividend decisions on published earnings, but on cash flows.The...

  9. Technology Licensing and Firm Innovation

    DEFF Research Database (Denmark)

    Moreira, Solon

    Although licensing has repeatedly been acknowledged to be a major vehicle for firms to acquire external knowledge, surprisingly little is known about how firms use it as part of their overall inventive efforts. Furthermore, with the exception of absorptive capacity, the organizational determinants...... relationship. The findings also suggest that high levels of Organizational Slack (available financial resources) strengthen the positive effect of licensing on innovation. However, higher levels of Organizational Myopia (the extent to which a firm draws on its own knowledge) can decrease the main effect of...

  10. Board Effectiveness in Small Firms

    OpenAIRE

    Söderqvist, Anette; WÀgar, Karolina

    2010-01-01

    Purpose: This study investigates boards of directors in small firms and explores the link between board effectiveness and the composition, roles and working styles of the boards. Design/methodology/approach: The study analyses data from a telephone survey of boards in 45 small firms. The survey included both the CEO and the chairperson of the board. Findings: The study identifies three groups of small firms: ‘paperboards’, ‘professional boards’, and ‘management ...

  11. Directors' human capital, firm strategy, and firm performance

    OpenAIRE

    Volonté, Christophe; Gantenbein, Pascal

    2016-01-01

    Ideally, corporations are directed by boards whose directors provide valuable human capital that match the firms’ strategy. We investigate how directors’ human capital (international experience, industrial know-how, CEO experience, and financial know-how) affects firm performance including the firm’s strategy (diversification and internationalization) and how human capital is related to acquisition strategies (non-diversifying and international acquisitions). Our sample consists of 560 firm-y...

  12. Estimates of Firms' Patent Rents from Firm Market Value

    OpenAIRE

    James Bessen

    2006-01-01

    A simple formal model shows that estimates of an upper bound on the value of firms' patent rents can be obtained from regressions on Tobin's Q. I test this model on a sample of US firms and find it is robust to a variety of considerations. The estimates correspond well with implied estimates derived from previous research. Also, these upper bound estimates are only modestly higher than estimates of patent value obtained from data on patent renewals international patent filings. This suggests ...

  13. Small Firm Lending Contracts: Do Banks Differentiate between Firms?

    OpenAIRE

    Cowling, Marc; Sugden, Roger

    1995-01-01

    This paper examines the role of interest rates and securities within the context of the small firm - bank lending relationship and questions whether banks alter their lending conditions on the basis of specific firm characteristics and the nature of the borrowing undertaken. The results suggest that the imposition of full collateralization reduces the role of interest rates considerably, although there is evidence of banks exercising their market power in more costly lending of the smallest o...

  14. Numerical Simulation of the Coagulation Dynamics of Blood

    OpenAIRE

    Bodnár, T.; Sequeira, A.

    2008-01-01

    The process of platelet activation and blood coagulation is quite complex and not yet completely understood. Recently, a phenomenological meaningful model of blood coagulation and clot formation in flowing blood that extends existing models to integrate biochemical, physiological and rheological factors, has been developed. The aim of this paper is to present results from a computational study of a simplified version of this coupled fluid-biochemistry model. A generalized Newtonian model with...

  15. Mathematical Model of Extrinsic Blood Coagulation Cascade Dynamic System

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The blood coagulation system is very important to life. This paper presents a mathematical blood coagulation model for the extrinsic pathway. This model simulates clotting factor VIII, which plays an important role in the coagulation mechanism. The mathematical model is used to study the equilibrium stability, orbit structure, attractors and global stability behavior, with conclusions in accordance with the physiological phenomena. Moreover, the results provide information about blood related illnesses, which can be used for further study of the coagulation mechanism.

  16. Blood Smear

    Science.gov (United States)

    ... testing may include tests such as: Iron tests Vitamin B12 and folate tests Flow cytometry immunophenotyping Bone marrow ... are too few, of if they don't function properly, the ability to form a clot becomes ...

  17. Firm Search for External Knowledge

    DEFF Research Database (Denmark)

    Sofka, Wolfgang; Grimpe, Christoph

    2012-01-01

    to experience the negative performance effects of oversearch. Based on a comprehensive sample of almost 8,000 firms from ten European countries, we find that institutions matter considerably for firms' search activity. Higher market orientation of institutions increases the effectiveness of firms' search...... ignored the institutional context that provides or denies access to external knowledge at the country level. Combining institutional and knowledge search theory, we suggest that the market orientation of the institutional environment and the magnitude of institutional change influence when firms begin...... for external knowledge while higher magnitudes of institutional change decrease it. Our results provide important insights for management on how to adapt search strategies to the institutional context....

  18. Web traffic and firm performance

    DEFF Research Database (Denmark)

    Farooq, Omar; Aguenaou, Samir

    2013-01-01

    Does the traffic generated by websites of firms signal anything to stock market participants? Does higher web-traffic translate into availability of more information and therefore lower agency problems? And if answers to above questions are in affirmative, does higher web-traffic traffic translate...... into better firm performance? This paper aims to answer these questions by documenting a positive relationship between the extent of web-traffic and firm performance in the MENA region during the 2010. We argue that higher web-traffic lowers the agency problems in firms by disseminating more information...... to stock market participants. Consequently, lower agency problems translate into better performance. Furthermore, we also show that agency reducing role of web-traffic is more pronounced in regimes where information environment is already bad. For example, our results show stronger impact of web...

  19. Firm Sustainability Performance Index Modeling

    OpenAIRE

    Che Wan Jasimah Bt Wan Mohamed Radzi; Hashem Salarzadeh Jenatabadi; Maisarah Binti Hasbullah

    2015-01-01

    The main objective of this paper is to bring a model for firm sustainability performance index by applying both classical and Bayesian structural equation modeling (parametric and semi-parametric modeling). Both techniques are considered to the research data collected based on a survey directed to the China, Taiwan, and Malaysia food manufacturing industry. For estimating firm sustainability performance index we consider three main indicators include knowledge management, organizational learn...

  20. Lobbying of Firms by Voters

    OpenAIRE

    Dahm, Matthias; Dur, Robert; Glazer, Amihai

    2009-01-01

    textabstractA firm may induce voters or elected politicians to support a policy it favors by suggesting that it is more likely to invest in a district whose voters or representatives support the policy. In equilibrium, no one vote may be decisive, and the policy may gain strong support though the majority of districts suffer from adoption of the program. When votes reveal information about the district, the firm's implicit promise or threat can be credible.

  1. Lobbying activities of multinational firms

    OpenAIRE

    Polk, Andreas

    2002-01-01

    This paper investigates if multinationals in.uence the political process through lobbying more effectively than national firms. First, I introduce a model which contrasts a multinational�s incentives for lobbying with those of a national firm. Then the effect of lobbying on the political decision is analyzed. I conclude that multinationals have smaller incentives to lobby because they have smaller stakes in national markets. But the effectiveness of lobbying by multinationals might be highe...

  2. Labour Turnover and Firm Performance

    OpenAIRE

    S. Brown; Garino, G.; C. Martin

    2007-01-01

    We explore the impact of labour turnover on firm performance by analysing the predictions of an extension of the efficiency wage model of Salop (1979) developed by Garino and Martin (2007), which separates incumbent and newly hired workers in the production function. Within this theoretical framework, an exogenous increase in the turnover rate can increase profits if firms do not choose wages unilaterally. We test the theoretical predictions of the model using UK cross-section establishment-l...

  3. Innovation Strategies and Firm Performance

    OpenAIRE

    Karlsson, Charlie; Tavassoli, Sam

    2015-01-01

    This paper analyzes the effect of various innovation strategies of firms on their future performance, captured by labour productivity. Using five waves of the Community Innovation Survey in Sweden, we have traced the innovative behaviour of firms over a decade, i.e. from 2002 to 2012. We distinguish between sixteen innovation strategies, which compose of Schumpeterian four types of innovations, i.e. process, product, marketing, and organizational (simple innovation strategies) plus various co...

  4. The nature of the firm

    OpenAIRE

    Xin LI

    2009-01-01

    This paper is intended to propose a relationship-based theory of the firm (R’BT), an alternative to the transaction cost theory. The R’BT takes relationship disharmony (rather than transaction costs) as its basic unit of analysis of the nature of the firm, and argues relationship disharmony derives from conflict of interests, a problem faced by any human organizations; to reduce the conflict of interests, the best way is to harmonize relationships by mutually accommodating or i...

  5. Dividend Policy in Regulated Firms

    OpenAIRE

    rondi, laura; Cambini, Carlo; bremberger, francisca; GUGLER, Klaus

    2013-01-01

    We study the impact of different regulatory and ownership regimes on the dividend policy of regulated firms. Using a panel of 106 publicly traded European electric utilities in the period 1986-2010, we link payout and smoothing decisions to the implementation of different regulatory mechanisms (cost plus vs. incentive regulation) and to firm ownership (state vs. private). After controlling for the potential endogeneity of the regulatory mechanism, our results show that utilities subject to i...

  6. Segmentation, Reconstruction, and Analysis of Blood Thrombus Formation in 3D 2-Photon Microscopy Images

    Directory of Open Access Journals (Sweden)

    Xu Zhiliang

    2010-01-01

    Full Text Available We study the problem of segmenting, reconstructing, and analyzing the structure growth of thrombi (clots in blood vessels in vivo based on 2-photon microscopic image data. First, we develop an algorithm for segmenting clots in 3D microscopic images based on density-based clustering and methods for dealing with imaging artifacts. Next, we apply the union-of-balls (or alpha-shape algorithm to reconstruct the boundary of clots in 3D. Finally, we perform experimental studies and analysis on the reconstructed clots and obtain quantitative data of thrombus growth and structures. We conduct experiments on laser-induced injuries in vessels of two types of mice (the wild type and the type with low levels of coagulation factor VII and analyze and compare the developing clot structures based on their reconstructed clots from image data. The results we obtain are of biomedical significance. Our quantitative analysis of the clot composition leads to better understanding of the thrombus development, and is valuable to the modeling and verification of computational simulation of thrombogenesis.

  7. Clot resolution after 3 weeks of anticoagulant treatment of pulmonary embolism: Comparison of computed tomography and perfusion scintigraphy

    NARCIS (Netherlands)

    Van Es, J.; Douma, Renee; Kamphuisen, P.W.; Gerdes, V.E.A.; Verhamme, P.; Wells, P.S.; Bounameaux, H.; Lensing, A.W.A.; Büller, H.R.

    2013-01-01

    Introduction: Little is known about the natural history of clot resolution in the initial weeks of anticoagulant therapy in patients with acute pulmonary embolism (PE). Aim: To assess clot resolution of acute PE with either computed tomography pulmonary angiography (CT-scan) or perfusion scintigraph

  8. Clot resolution after 3 weeks of anticoagulant treatment for pulmonary embolism : comparison of computed tomography and perfusion scintigraphy

    NARCIS (Netherlands)

    van Es, J.; Douma, R. A.; Kamphuisen, P. W.; Gerdes, V. E. A.; Verhamme, P.; Wells, P. S.; Bounameaux, H.; Lensing, A. W. A.; Bueller, H. R.

    2013-01-01

    Introduction Little is known about the natural history of clot resolution in the initial weeks of anticoagulant therapy in patients with acute pulmonary embolism (PE). Clot resolution of acute PE was assessed with either computed tomography pulmonary angiography scan (CT-scan) or perfusion scintigra

  9. Extraction of mRNA from coagulated horse blood and analysis of inflammation-related cytokine responses to coagulation

    DEFF Research Database (Denmark)

    Bovbjerg, Kirsten Katrine Lindegaard; Heegaard, Peter M. H.; Skovgaard, Kerstin

    2010-01-01

    Coagulated blood is a rich source of mRNA that allows the study of the regulation of expression of cytokine and other genes. However, while several methods are available for isolation of RNA from whole blood and tissues, protocols for purification of mRNA from clotted blood are not generally...

  10. Firm Culture and Leadership as Firm Performance Predictors: a Resource-Based Perspective

    OpenAIRE

    Wilderom, C.P.M.; van den Berg, P

    2000-01-01

    In this study, we tested part of the resource-based view of the firm by examining two 'soft' resources, firm culture and top leadership, as predictors of 'hard' or bottom-line firm performance.Transformational top leadership was found to predict firm performance directly while the link between firm culture and firm performance was indirect: via transformational top leadership.Firm culture was operationalized as the employees' views about the degree of optimization of four organizational pract...

  11. Purification and identification of a clotting protein from the hemolymph of Chinese shrimp ( Fenneropenaeus chinensis)

    Science.gov (United States)

    Wang, Baojie; Peng, Hongni; Liu, Mei; Jiang, Keyong; Zhang, Guofan; Wang, Lei

    2013-09-01

    The clotting protein (CP) plays important and diverse roles in crustaceans, such as coagulation and lipid transportation. A clotting protein was purified from the hemolymph of Chinese shrimp Fenneropenaeus chinensis (named as Fc-CP) with Q sepharose HP anion-exchange chromatography and phenyl sepharose HP hydrophobic interaction chromatography. Fc-CP was able to form stable clots in vitro in the presence of hemocyte lysate and Ca2+, suggesting that the clotting reaction is catalyzed by a Ca2+-dependent transglutaminase in shrimp hemocytes. The molecular mass of Fc-CP was 380 kDa under non-reducing conditions and 190 kDa under reducing conditions as was determined with SDS-PAGE. CP exists as disulfide-linked homodimers and oligomers. The N-terminal amino acid sequence of Fc-CP was identical to that of shrimps including Penaeus monodon, Farfantepenaeus paulensis and Litopenaeus vannamei; and similar to that of other decapods. The purified Fc-CP was digested with trypsin and verified on an ABI 4700 matrix-assisted laser desorption/ionization tandem time-of-flight (MALDI-TOF/TOF) mass spectrometry. Our results will aid to better understanding the coagulation mechanism of shrimp hemolymph.

  12. Thromboelastography to Monitor Clotting/Bleeding Complications in Patients Treated with the Molecular Adsorbent Recirculating System

    Directory of Open Access Journals (Sweden)

    Esther B. Bachli

    2011-01-01

    Full Text Available Background. The Molecular Adsorbent Recirculating System (MARS has been shown to clear albumin-bound toxins from patients with liver failure but might cause bleeding complications potentially obscuring survival benefits. We hypothesized that monitoring clotting parameters and bed-side thromboelastography allows to reduce bleeding complications. Methods. Retrospective analysis of 25 MARS sessions during which clotting parameters were monitored by a standardized protocol. Results. During MARS therapy median INR increased significantly from 1.7 to 1.9 platelet count and fibrinogen content decreased significantly from 57 fL−1 to 42 fL−1 and 2.1 g/L to 1.5 g/L. Nine relevant complications occurred: the MARS system clotted 6 times 3 times we observed hemorrhages. Absent thrombocytopenia and elevated plasma fibrinogen predicted clotting of the MARS system (ROC 0.94 and 0.82. Fibrinolysis, detected by thromboelastography, uniquely predicted bleeding events. Conclusion. Bed-side thromboelastography and close monitoring of coagulation parameters can predict and, therefore, help prevent bleeding complications during MARS therapy.

  13. Merger incentives and the failing firm defense

    NARCIS (Netherlands)

    Bouckaert, J.M.C.; Kort, P.M.

    2014-01-01

    The merger incentives between profitable firms differ fundamentally from the incentives of a profitable firm to merge with a failing firm. We investigate these incentives under different modes of price competition and Cournot behavior. Our main finding is that firms strictly prefer exit of the faili

  14. Impact of export destinations on firm performance

    OpenAIRE

    Cebeci, Tolga

    2014-01-01

    This paper evaluates the role of export destinations on productivity, employment, and wages of Turkish firms by comparing the performance of firms that export to low-income destinations and high-income destinations with firms that do not export. A combination of propensity score matching and difference-in-differences methods are employed on a rich set of firm observables, including sector,...

  15. Quality Signaling, Advertising and Firm Numbers

    OpenAIRE

    Tsui, Hsiao-Chien; Lin, Yi-Shiun

    2013-01-01

    This paper investigates whether low-quality firms can pretend through advertising to be high-quality firms, which is a signal of product quality, when the number of firms increases. We assume that consumers remain loyal to high-quality firms after purchasing high-quality products and will therefore not patronize low-quality firms, which pretend through advertising to be high-quality firms. Our results indicate that the possibility of low-quality firms entering the high-quality market declines...

  16. Foreign Entry and Heterogeneous Growth of Firms

    DEFF Research Database (Denmark)

    Deng, Paul Duo; Jefferson, Gary H.

    We adopt the framework of Schumpeterian creative destruction formalized by Aghion et al. (2009) to analyze the impact of foreign entry on the productivity growth of domestic firms. In the face of foreign entry, domestic firms exhibit heterogeneous patterns of growth depending on their technological...... distance from foreign firms. Domestic firms with smaller technological distance from their foreign counterparts tend to experience faster productivity growth, while firms with larger technological distance tend to lag further behind. We test this hypothesis using a unique firm-level data of Chinese...... manufacturing. Our empirical results confirm that foreign entry indeed generates strong heterogeneous growth patterns among domestic firms....

  17. Correlation of fibrinogen level and absorbance change in both PT and APTT clotting curves on BCSXP

    Institute of Scientific and Technical Information of China (English)

    Xiaojie Zhang; Bing Bai

    2008-01-01

    Objective: To investigate the correlation of fibrinogen level and absorbance change in both PT and APTT clotting curves on BCSXP Analyzer. Methods:A serial of standard fibrinogen and 250 patient plasma samples with different qualities(normal, hemolysis,icterus, and lipemia) were run on BCSXP for assays PT, APTT and Fibrinogen. The absorbance change(DeltaA) from baseline to plateau in clotting curve was retrieved and analyzed on its correlation with the Fibrinogen result. Influence of plasma quality and PT/APTT result on this correlation was also studied respectively. Results:Both PT-DeltaA and APTT-DeltaA showed good linear regression with fibrinogen level in the sample, with Re close to 0.90 in both standard and patient samples. Hemolysis(H), itcterus(1) and lipemia(L) of the sample with valid clotting curves were found to have no significant difference in this correlation from normal(N) sample(R2: 0.83H, 0.92I 0.81L and 0.79N in PT; 0.89H, 0.95I, 0.91L and 0.89N in APTT) in either PT or APTT curve. PT or APTT result also has little impact on this correlation(0.71 in range 7 ~ 10 sec, 0.56 in10 ~ 20 sec, and 0.70 in 20 sec~; R2 in APTT: 0.88 in 20~30 sec,0.92 in 30~40 sec, and 0.95 in 40 sec~). Conclusion:The absorbance change in either PT or APTT clotting curve correlates well with the fibrinogen level in plasma, which is independent of plasma quality PT or APTT results. The absorbance change can be used as an alternative way to roughly estimate fibrinogen level in either PT or APTT clotting curve when the result of clauss-based fibrinogen measurement is not available.

  18. Process Ambidexterity for Entrepreneurial Firms

    Directory of Open Access Journals (Sweden)

    Sonia D. Bot

    2012-04-01

    Full Text Available Technology-based entrepreneurial firms must effectively support both mainstream exploitation and new-stream exploration in order to remain competitive for the long term. The processes that support exploitation and exploration initiatives are different in terms of logistics, payoff horizons, and capabilities. Few firms are able to strike a balance between the two, where mainstream exploitation usually trumps new-stream exploration. The ultimate goal is for the firm to operate effectively in a repeatable, scalable, and systematic manner, rather than relying on good luck and hoping either to come up with the next innovation or for the product to function according to its requirements. This article builds on the author’s years of experience in building businesses and transforming medium and large-sized, entrepreneurial technology firms, leading large-scale breakthrough and sustained performance improvements by using and evolving Lean Six Sigma methodologies, and reviews of technology innovation management and entrepreneurship literature. This article provides a process-based perspective to understanding and addressing the issues on balancing mainstream exploitation and new-stream exploration in medium and large-sized entrepreneurial firms and extending it to startups. The resulting capability is known as process ambidexterity and requires disciplined, agile, and lean business management.

  19. The Case of Japanese Manufacturing Firms

    OpenAIRE

    Ando, Mitsuyo; Akie IRIYAMA

    2009-01-01

    This paper examines how international production/distribution networks provide individual firms with exporting/importing responsiveness to exchange rate movements. With the micro-data of Japanese manufacturing firms from 1994 to 2004, we find that firms' exports tend to respond to exchange rate movements, in particular (1) when firms are large in size, (2) when majority-owned affiliates are dominant among their foreign affiliates, and (3) when their intra-firm trade ratio is moderately high. ...

  20. Multiple-product firms and product switching

    OpenAIRE

    Andrew B. Bernard; Redding, Stephen; Peter K. Schott

    2010-01-01

    This paper examines the frequency, pervasiveness, and determinants of product switching by US manufacturing firms. We find that one-half of firms alter their mix of five-digit SIC products every five years, that product switching is correlated with both firm- and firm-product attributes, and that product adding and dropping induce large changes in firm scope. The behavior we observe is consistent with a natural generalization of existing theories of industry dynamics that incorporates endogen...

  1. Shared vision promotes family firm performance

    OpenAIRE

    Neff, John E.

    2015-01-01

    A clear picture of the influential drivers of private family firm performance has proven to be an elusive target. The unique characteristics of private family owned firms necessitate a broader, non-financial approach to reveal firm performance drivers. This research study sought to specify and evaluate the themes that distinguish successful family firms from less successful family firms. In addition, this study explored the possibility that these themes collectively form an effective organiza...

  2. Lobbying and the Power of Multinational Firms

    OpenAIRE

    Polk, Andreas; Schmutzler, Armin; Müller, Adrian

    2010-01-01

    Can multinational firms exert more power than national firms by influencing politics through lobbying? To answer this question, we analyze the extent of national environmental regulation when policy is determined in a lobbying game between a government and firm. We compare the resulting equilibrium regulation levels, outputs and welfare for national and multinational firms, depending on such parameters as the potential environmental damages, transportation costs and the influence of the firm....

  3. THE INTERNAL COSTS OF THE FIRM

    OpenAIRE

    Monica Dudian; Aurelia Ştefănescu; Rodica Gherghina; Ioana Duca

    2007-01-01

    The Economics of the firm is affecting in the latest year of a changing perspective, from the firm like production function and market actor to internal organization of the firm. Producing suppose resource allocation by the entrepreneurs or/and managers and cooperation between individuals inside the firm. The existence of the firm like institution implies transaction costs, agency costs, the costs of creating incitation and the costs of reducing flexibility. In addition, the existence of the ...

  4. Bundling and joint marketing by rival firms

    OpenAIRE

    Jeitschko, Thomas D.; Jung, Yeonjei; Kim, Jaesoo

    2014-01-01

    We study joint marketing arrangements by competing firms who engage in price discrimination between consumers who patronize only one firm (single purchasing) and those who purchase from both competitors (bundle purchasers). Two types of joint marketing are considered. Firms either commit to a component-price that applies to bundle-purchasers and then firms set stand-alone prices for single purchasers; or firms commit to a rebate off their stand alone price that will be applied to bundle-purch...

  5. The Relationship between Offshoring Strategies and Firm Performance: Impact of innovation, absorptive capacity and firm size

    NARCIS (Netherlands)

    M.W. Roza-van Vuren (Marja)

    2011-01-01

    textabstractHow do offshoring strategies impact firm performance? And how are innovation, absorptive capacity and firm size influencing this relationship? This research investigates how firms of varying size, well-established firms and growing firms may profit from relocating business activities to

  6. Firm Culture and Leadership as Firm Performance Predictors : a Resource-Based Perspective

    NARCIS (Netherlands)

    Wilderom, C.P.M.; van den Berg, P.

    2000-01-01

    In this study, we tested part of the resource-based view of the firm by examining two 'soft' resources, firm culture and top leadership, as predictors of 'hard' or bottom-line firm performance.Transformational top leadership was found to predict firm performance directly while the link between firm

  7. New method for detection of blood coagulation using fiber-optic sensor

    Science.gov (United States)

    Fediay, Sergey G.; Kuznetzov, Alexsey V.

    1991-07-01

    The detection of blood coagulation is very important in therapeutics and surgery. It is necessary to determine the overall time taken for blood clotting, production rate of thrombin, presence or absence of blood coagulation factors, etc. In this paper a new method for detection of blood coagulation is presented. This method is based on the fiber-optic sensor and allows for the study of different ways of blood clotting (such as blood coagulation and platelets aggregation) separately, thus enhancing the precision of determination. The method for determining the blood coagulation presented possesses high precision in monitoring the process of coagulation. An elaborate mathematical model of the process of blood coagulation has been developed to help the computer handle obtained data.

  8. Knowledge management in the firm

    DEFF Research Database (Denmark)

    Rasmussen, Palle; Nielsen, Peter

    2011-01-01

    Purpose – The purpose of this paper is to set focus on, and discuss the concept of knowledge, and show how the interrelations between knowledge and other concepts, such as learning, have become a decisive element in managing human resources and firm performance. Design/methodology/approach – The...... dimensions of knowledge management are identified and related to learning, organizational configurations, human resources management and institutional environments in order to identify and percent the most important approaches to knowledge management and the development over time. Findings – Creating......, transforming and utilizing various kinds of knowledge as a firm-specific asset is a very important element of firm competitiveness and innovative performance. In managing knowledge learning and innovation learning approaches are central. The paper identifies various approaches to learning and strategies to...

  9. Knowledge Management in Small Firms

    Science.gov (United States)

    Panyasorn, Jessada; Panteli, Niki; Powell, Philip

    This paper explores knowledge management in small and medium-sized firms (SMEs). It investigates the use of Lotus Notes in SMEs of a developing country as a counterpoint to the large firm, developed country emphasis of existing research. It develops taxonomy of Lotus Notes use within the context of different knowledge management processes; notably communicating, co-ordinating and collaborating. The study employs an interpretive approach using three case studies. The key findings suggest that publishing, searching, sharing and retrieving are the user modes for enabling sharing and storing information. Evidence of knowledge creation is found at the departmental level but not at the organizational level. Further, small firms may explore more groupware potential than large organizations and this reflects their different context. Finally, implications for further research are identified.

  10. Consumer Networks and Firm Reputation

    DEFF Research Database (Denmark)

    Huck, Steffen; Lünser, Gabriele K.; Tyran, Jean-Robert

    Arguing that consumers are the carriers of firms' reputations, we examine the role of consumer networks for trust in markets that suffer from moral hazard. When consumers are embedded in a network, they can exchange information with their neighbours about their private experiences with different ...... sellers. We find that such information exchange fosters firms' incentives for reputation building and, thus, enhances trust and efficiency in markets. This efficiency-enhancing effect is already achieved with a rather low level of network density......Arguing that consumers are the carriers of firms' reputations, we examine the role of consumer networks for trust in markets that suffer from moral hazard. When consumers are embedded in a network, they can exchange information with their neighbours about their private experiences with different...

  11. Rotary blood pump

    Science.gov (United States)

    Benkowski, Robert J. (Inventor); Kiris, Cetin (Inventor); Kwak, Dochan (Inventor); Rosenbaum, Bernard J. (Inventor); Bacak, James W. (Inventor); DeBakey, Michael E. (Inventor)

    1999-01-01

    A blood pump that comprises a pump housing having a blood flow path therethrough, a blood inlet, and a blood outlet; a stator mounted to the pump housing, the stator having a stator field winding for producing a stator magnetic field; a flow straightener located within the pump housing, and comprising a flow straightener hub and at least one flow straightener blade attached to the flow straightener hub; a rotor mounted within the pump housing for rotation in response to the stator magnetic field, the rotor comprising an inducer and an impeller; the inducer being located downstream of the flow straightener, and comprising an inducer hub and at least one inducer blade attached to the inducer hub; the impeller being located downstream of the inducer, and comprising an impeller hub and at least one impeller blade attached to the impeller hub; and preferably also comprising a diffuser downstream of the impeller, the diffuser comprising a diffuser hub and at least one diffuser blade. Blood flow stagnation and clot formation within the pump are minimized by, among other things, providing the inducer hub with a diameter greater than the diameter of the flow straightener hub; by optimizing the axial spacing between the flow straightener hub and the inducer hub, and between the impeller hub and the diffuser hub; by optimizing the inlet angle of the diffuser blades; and by providing fillets or curved transitions between the upstream end of the inducer hub and the shaft mounted therein, and between the impeller hub and the shaft mounted therein.

  12. Human Capital in New Firms

    OpenAIRE

    Müller, Bettina

    2009-01-01

    This dissertation is a collection of three stand-alone research papers on the composition of human capital in newly founded firms. The papers are all empirical but they are closely related to two theoretical approaches. The first approach is the jack-ofall-trades model by Lazear (2005) and the second the O-ring theory introduced by Kremer (1993) and applied to new firms by Fabel (2004a,b) and Fabel and Weber (2005). Besides contributing to the search of stylised facts about the effects of the...

  13. Drivers of Discretionary Firm Donations in Brazil

    Directory of Open Access Journals (Sweden)

    Rodrigo Bandeira-de-Mello

    2008-10-01

    Full Text Available Discretionary firm donation is usually related to the stakeholder theory and corporate social performance. Although theoretical explanations for this social behavior are pervasive in related literature, empirical modeling remains underdeveloped. We developed an explanatory structural model of discretionary firm donation using firm and industry level indicators. Unlike previous research, we estimated the explanatory power of the construct we called stakeholder orientation. Our tentative model was tested on a Brazilian sample of 101 publicly traded donor firms, using data on firm donations to social projects and to political candidates in electoral campaigns. The main results suggest that discretionary donation seems to be a strategy for managing conflicting claims in highly stakeholder oriented firms; the characteristics of the firm are more important than industry effects in explaining firm donations; and large firms, showing slack resources, and with a less concentrated ownership structure tend to engage in discretionary donation more intensively.

  14. Chondrogenic differentiation of marrow clots after microfracture with BMSC-derived ECM scaffold in vitro.

    Science.gov (United States)

    Wei, Bo; Jin, Chengzhe; Xu, Yan; Du, Xiaotao; Yan, Chao; Tang, Cheng; Ansari, Mujtaba; Wang, Liming

    2014-10-01

    Repairing articular cartilage by combining microfracture and various scaffolds has been extensively performed in in vivo animal models. We previously described a novel extracellular matrix (ECM) scaffold for cartilage tissue engineering. The aim of this study was to investigate the effect of a bone marrow-derived mesenchymal stem cells-derived ECM (BMSC-dECM) scaffold on the chondrogenic differentiation of marrow clots following microfracture in vitro. In this study, we manufactured the BMSC-dECM scaffold using a freeze-drying method. To obtain the marrow clots, a full-thickness cartilage defect was established and microholes were created in the trochlear groove of New Zealand white rabbits. The samples were divided and cultured in vitro for 1, 2, 4, and 8 weeks. The samples included a culture of the marrow clot alone (Group 1), a culture of the marrow clot with transforming growth factor-beta 3 (TGF-β3) (Group 2), a culture of the composite of the BMSC-dECM scaffold and the marrow clot alone (Group 3), and a culture of the composite with TGF-β3 (Group 4). A smooth and glossy surface was observed in Group 2 and Group 4 over time, but the surface for Group 4 was larger from week 1 onward. Compressive strength gradually increased in Groups 2 and 4, and greater increases were observed in Group 4 during the 8-week culture period. Enhanced cartilage-like matrix deposition of glycosaminoglycan (GAG) and type II collagen were confirmed by Safranin O and immunohistochemistry staining, respectively, in Groups 2 and 4. The GAG and collagen contents also gradually increased over time in Groups 2 and 4; the increase was greater in Group 4. In addition, real-time-polymerase chain reaction demonstrated that the expression of chondrogenic genes, such as COL2, ACAN, and SOX9, was gradually upregulated in Groups 2 and 4. However, greater increases in the expression of these cartilage-like genes were observed in Group 4 from week 4 onward. Our results suggest that the BMSC

  15. Experiences of Emerging Economy Firms

    DEFF Research Database (Denmark)

    of foreign and emerging issues when they expand their activities in various contexts, enter, exit, and re-enter overseas markets; they have to overcome institutional barriers, adapt the cultural challenges in foreign markets, undergo the impact of large multinational firms from developed economies...

  16. Improving the firm's environmental conduct

    DEFF Research Database (Denmark)

    Knudsen, Thorbjørn; Koed Madsen, Tage

    2001-01-01

    lead to strategic advantage and, thus, economic gains at the firm level. In view of the great importance of this claim, the purpose of the present article was to apply resource-based insights in order to develop this reasoning further and provide an empirical test of three hypotheses related to the...

  17. The firm-nature relationship

    DEFF Research Database (Denmark)

    Ulhøi, John Parm; Madsen, Henning

    2005-01-01

    Taking the stakeholder concept of the firm as a starting point, the paper presents data and analyses from a longitudinal study initiated in 1995 and repeated every four years. In discussing state-of-the-art insights and experiences, the paper identifies challenges which, if adequately addressed, ...

  18. Firm default and aggregate fluctuations

    NARCIS (Netherlands)

    Jacobson, Tor; Linde, Jesper; Roszbach, Kasper

    2013-01-01

    This paper studies the relationship between macroeconomic fluctuations and corporate defaults while conditioning on industry affiliation and an extensive set of firm-specific factors. By using a panel data set for virtually all incorporated Swedish businesses over 1990-2009, a period which includes

  19. Firm ownership structures: dynamic development

    Czech Academy of Sciences Publication Activity Database

    Kočenda, Evžen; Valachy, Juraj

    2002-01-01

    Roč. 11, č. 3 (2002), s. 255-268. ISSN 1210-0455 R&D Projects: GA AV ČR KSK9058117 Institutional research plan: CEZ:AV0Z7085904 Keywords : ownership structure * privatized firms * industry sector Subject RIV: AH - Economics

  20. Small firm transformation through IS

    NARCIS (Netherlands)

    Levy, Margi; Powell, Philip

    2008-01-01

    Globally, Small and Medium-sized Enterprises (SMEs) are encouraged, particularly by governments, to embrace c-business. Fully adopting e-business involves substantial change in firms, both internally and externally. However, there is little understanding of the mechanisms by which such business tran

  1. Firm Based Trade Models and Turkish Economy

    Directory of Open Access Journals (Sweden)

    Nilüfer ARGIN

    2015-12-01

    Full Text Available Among all international trade models, only The Firm Based Trade Models explains firm’s action and behavior in the world trade. The Firm Based Trade Models focuses on the trade behavior of individual firms that actually make intra industry trade. Firm Based Trade Models can explain globalization process truly. These approaches include multinational cooperation, supply chain and outsourcing also. Our paper aims to explain and analyze Turkish export with Firm Based Trade Models’ context. We use UNCTAD data on exports by SITC Rev 3 categorization to explain total export and 255 products and calculate intensive-extensive margins of Turkish firms.

  2. Toward an Integrative Theory of the Firm

    DEFF Research Database (Denmark)

    Li, Xin

    This paper argues that the existing four major theories of the firm, i.e., the transaction cost theory, resource-based view, the entrepreneurial theory, and the stakeholder theory, are all insightful yet partial because each of them has a particular focus on the phenomenon of the firm. To better...... understand the nature and behaviors of the firm, we need a comprehensive yet integrative theory. Toward this end, this paper proposes a relationship-based theory of the firm (R’BT) which claims that it is the relationships between the entrepreneur and other individuals or firms that determine the existence......, boundary, internal organization and competitive advantage of the firm....

  3. Entrepreneurship and the Economics of the Firm

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul

    The study of entrepreneurship and the study of economic organizing lack contact. In fact, the modern theory of the firm virtually ignores entrepreneurship, while the literature on entrepreneurship often sees little value in the economic theory of the firm. In contrast, we argue in this chapter that...... entrepreneurship theory and the theory of the firm can be usefully integrated, and that doing so would improve both bodies of theory. Adding the entrepreneur to the theory of the firm provides a dynamic view that the overly static analysis of firm organizing cannot support. Moreover, adding the firm to the study...... of the entrepreneur provides important clues to how we can understand entrepreneurship....

  4. Blood coagulation and its alterations in hemorrhagic and thrombotic disorders.

    OpenAIRE

    Rapaport, S I

    1993-01-01

    Clinical observations have added to the understanding of basic mechanisms of blood coagulation and its alterations in certain hemorrhagic and thrombotic states. Much clinical evidence exists for concluding that the exposure of blood to tissue factor (thromboplastin) on tissue cells represents the key event initiating fibrin clot formation after tissue injury. This then results in the formation of activated factor VII (VIIa)-tissue factor complexes, which must activate both factor X and factor...

  5. Topographic Cues Reveal Two Distinct Spreading Mechanisms in Blood Platelets

    OpenAIRE

    Rabea Sandmann; Sarah Köster

    2016-01-01

    Blood platelets are instrumental in blood clotting and are thus heavily involved in early wound closure. After adhering to a substrate they spread by forming protrusions like lamellipodia and filopodia. However, the interaction of these protrusions with the physical environment of platelets while spreading is not fully understood. Here we dynamically image platelets during this spreading process and compare their behavior on smooth and on structured substrates. In particular we analyze the te...

  6. Innovation-economic and spatial aspects of firm growth - The contribution of firm-internal and firm-external factors

    OpenAIRE

    Schimke, Antje

    2013-01-01

    This thesis is explorative in nature. Based on empirical investigations of different research fields (i.e. Geography and Economics), it analyses firm growth in terms of factors and sources that come internal and external to firms. This book deals with the integration of different growth related dimensions, in particular with factors and knowledge sources for investigating and analysing growth processes of firms. Firm grow...

  7. Hereditary combined deficiency of the vitamin K-dependent clotting factors

    OpenAIRE

    Mariani Guglielmo; Napolitano Mariasanta; Lapecorella Mario

    2010-01-01

    Abstract Hereditary combined vitamin K-dependent clotting factors deficiency (VKCFD) is a rare congenital bleeding disorder resulting from variably decreased levels of coagulation factors II, VII, IX and X as well as natural anticoagulants protein C, protein S and protein Z. The spectrum of bleeding symptoms ranges from mild to severe with onset in the neonatal period in severe cases. The bleeding symptoms are often life-threatening, occur both spontaneously and in a surgical setting, and usu...

  8. Intracorneal blood removal six weeks after canaloplasty

    Directory of Open Access Journals (Sweden)

    Alberto Rossetti

    2013-01-01

    Full Text Available In a 71-year-old patient with bilateral open-angle glaucoma, intracorneal blood was found after a canaloplasty procedure in the right eye. Six weeks after surgery on ultrasound biomicroscopy examination, liquified blood and blood clots could be observed nasally in the deep corneal stroma close to the Descemet′s membrane. The intracorneal blood was washed out with balanced saline solution following deep corneal incision and lamellar dissection. Descemet′s membrane was reattached with air injection into the anterior chamber. Two months later, visual acuity improved to 20/50, intraocular pressure was 16 mm Hg without medication and confocal microscopy showed deep stromal folds and limited endothelial cell loss. Viscoelastic entering the cornea at Schwalbe′s line and reflux of blood from the collector channels to Schlemm′s canal can account for corneal hematoma. Even six weeks after canaloplasty, successful blood removal could be fulfilled without rupturing the Descemet′s membrane.

  9. Continuous production of cheese by immobilized milk-clotting protease from aspergillus niger MC4

    Science.gov (United States)

    Channe; Shewale

    1998-11-01

    Milk clotting protease from Aspergillus niger MC4 immobilized on glycidyl methacrylate-pentaerythritol triacrylate copolymer GP4 was used for continuous production of cheese using a packed bed reactor. Factors affecting the hydrolysis of kappa-casein and clot formation were studied. Acidified milk (pH 5.8) preincubated at 37 degreesC when passed through the column at a flow rate of 80 mL/min attained the required degree of hydrolysis of kappa-casein for the coagulation in a single pass. Fortification of the hydrolyzed milk with CaCl2 and FeCl3 to a final concentration of 0.01 and 0.02 M, respectively, and incubation of fortified milk at 60 degreesC for 2 h resulted in a hard cake of cheese. The yield of raw cheese was 28 g/100 mL of milk. The immobilized milk-clotting protease was used for 60 days (8 h/day) without any loss in productivity. PMID:9841651

  10. Real firms, transaction costs and firm development: a suggested formalisation

    OpenAIRE

    McHardy, J.P.; Dietrich, M.; Krafft, J.

    2015-01-01

    The motivation of this discussion is threefold: to integrate transaction costs (TCs) into a standard model of the firm; to examine the interaction between organisational factors (i.e. TCs) and standard demand-cost factors; and to analyse key propositions of transaction cost economics with the general model. Two sets of results are derived. First, when analysis is based on significant interaction between organisational effort and production costs two possible organisational solutions can exist...

  11. Contact activation of blood coagulation on a defined kaolin/collagen surface in a microfluidic assay

    OpenAIRE

    Zhu, Shu; Diamond, Scott L.

    2014-01-01

    Generation of active Factor XII (FXIIa) triggers blood clotting on artificial surfaces and may also enhance intravascular thrombosis. We developed a patterned kaolin (0 to 0.3 pg/μm2)/type 1 collagen fibril surface for controlled microfluidic clotting assays. Perfusion of whole blood (treated only with a low level of 4 μg/mL of the XIIa inhibitor, corn trypsin inhibitor) drove platelet deposition followed by fibrin formation. At venous wall shear rate (100 s−1), kaolin accelerated onset of fi...

  12. Do foreign-owned firms pay more?

    OpenAIRE

    Harrison, Ann E.; Scorse, Jason

    2008-01-01

    This paper uses Indonesian data to analyze the impact of foreign ownership on wages. After controlling for worker and firm characteristics, we find that foreign firms pay a wage premium, which is larger for skilled relative to unskilled workers.

  13. How do Economic Crises Impact Firm Boundaries?

    DEFF Research Database (Denmark)

    Foss, Kirsten

    2010-01-01

    How economic crises impact the boundaries of firms has been offered virtually no attention in the literature on the theory of the firm. I review the best-known theories of the firm and identify the variables that matter for the explanation of firm boundaries. I then examine how an economic crisis...... may impact these variables and change efficient firm boundaries. The various theories of the firm have difficulties explaining how firms efficiently adapt their boundaries to such prominent characteristics of economic crisis as declining demand and increased costs of external finance. However, all...... these theories stress uncertainty as an antecedent of firm organization, and as uncertainty is also an important characteristic of an economic crisis I examine how uncertainty is allowed to play out in the various theories in order to identify what predictions we can derive from the theory regarding...

  14. Modelling Firm Innovation using Panel Probit Estimators.

    OpenAIRE

    Mark N. Harris; Mark Rogers; Anthony Siouclis

    2001-01-01

    Firm-level innovation is investigated using three probit panel estimators, which control for unobserved heterogeneity, and a standard probit estimator. Results indicate the standard probit model is misspecified and that inter-firm networks are important for innovation.

  15. Heterogeneity in Firm Performance During Economic Crisis

    Directory of Open Access Journals (Sweden)

    Sergio Bruni

    2014-06-01

    Full Text Available What happens to firms during periods of deep economic crisis? Did different types of firms perform differently under the economic crisis? With the aid of a rich database and focusing on the literature regarding the growth of firms, this paper investigates the relative profitability performance of Italian firms during the current economic crisis, exploring those factors, which help certain firms to do relatively better even in the slowdown period. Some preliminary results show that the Italian firms that are relatively young in age, with relatively better current liquidity and more focused on domestic market have performed better than other firms. Furthermore, firms operating in high-tech and in highly concentrated sectors have enjoyed a better performance in this period.

  16. Agency, firm growth, and managerial turnover

    OpenAIRE

    Anderson, Ronald W.; Bustamante, Cecilia, 1932-2006; Guibaud, Stéphane

    2012-01-01

    We study the relation between firm growth and managerial incentive provision under moral hazard when a long-lived firm is operated by a sequence of managers. In our model, firms replace their managers not only upon poor performance to provide incentives, but also when outside managers are at a comparative advantage to lead the firm through a new growth phase. We show how the optimal contract can be implemented with a system of deferred compensation credit and bonuses, along with dismissal and...

  17. Industry-specific firm growth and agglomeration

    OpenAIRE

    Duschl, Matthias; Scholl, Tobias; Brenner, Thomas; Luxen, Dennis; Raschke, Falk

    2013-01-01

    This paper studies the industry-specific relationship between industrial clustering and firm growth. The literature usually considers industrial clusters as positive for the general economic development of regions. In particular, their relationship with the formation rate of new firms and the survival rate of existing firms is well documented. However, the impact of agglomeration effects on growth prospects of firms is less clear. Because of the heterogeneity of industries, different agglomer...

  18. Spanish Multinational Firm and its Internationalization Process

    OpenAIRE

    David de Matías Batalla

    2015-01-01

    The article responds to the need to study and analyze the evolution of the Spanish multinational firm in order to be able to identify the characteristics of success and what kind of factors are drivers to internationalize the activities in the Spanish economy. The first part reviews the evolution of the Spanish firm internationalization; meanwhile the second part describes the characteristics of Spanish multinational firm, resulted of a survey of 166 Spanish multinational firms.

  19. On Firms' Preferences for Product Differentiation

    OpenAIRE

    Rajeev Tyagi

    2005-01-01

    We examine firms' preferences for product differentiation when a firm has a demand-side and/or a cost-side advantage over its competitor. We show that if the magnitude of these advantages is small, then both firms prefer more differentiated products. However, if the magnitude of demand-side (cost-side) advantage is larger, then only the advantaged (disadvantaged) firm prefers more differentiated products.

  20. International Strategies of Non-Dominant Firms

    OpenAIRE

    Briance Mascarenhas

    1986-01-01

    There has been a growing interest in how follower firms can compete with industry leaders. This article documents the use of international strategies by some non-dominant firms to avoid direct competition with industry leaders. Twenty-five cases of international strategies used by non-dominant firms in a variety of industries were cluster analyzed to identify common strategies. Seven different strategies were identified together with their attendant firm characteristics, stage of industry int...

  1. Enforcement of Labor Regulation and Firm Size

    OpenAIRE

    De Almeida, Rita; Carneiro, Pedro

    2009-01-01

    This paper investigates how the enforcement of labor regulation affects firm size and other firm characteristics in Brazil. We explore firm level data on employment, capital, and output, city level data on economic characteristics, and new administrative data measuring enforcement of regulation at the city level. Since enforcement may be endogenous, we instrument this variable with the distance between the city where the firm is located and surrounding enforcement offices, while controlling f...

  2. Firm Growth from a Knowledge Structure Perspective

    OpenAIRE

    Keld Laursen; Volker Mahnke; Per Vejrup-Hansen

    1999-01-01

    Although there are several theories of growth of the firm, the literature is limited in two interrelated respects. First, empirical evidence does not match well theoretical predictions. Second, the firm growth literature does not address the structure of knowledge both in firms and sectors as well as knowledge flows between them. Based on existing theoretical and empirical literature, the paper outlines an ‘appreciative’ theory of firm growth and presents new testable hypotheses to inform pre...

  3. Innovation and jobs: evidence from manufacturing firms

    OpenAIRE

    Garcia, Angel; Jaumandreu, Jordi; Cesar RODRIGUEZ

    2004-01-01

    This paper is aimed at structurally assessing the employment effects of the innovative activities of firms. We estimate firm level displacement and compensation effects in a model in which the stock of knowledge capital raises firm relative efficiency through process innovations and firm demand through product innovations. Displacement is estimated from the elasticity of employment with respect to innovation in the (conditional or Hicksian) demand for labour. Compensation effects are estimate...

  4. Does Labour Diversity affect Firm Productivity?

    DEFF Research Database (Denmark)

    Parrotta, Pierpaolo; Pozzoli, Dario; Pytlikova, Mariola

    that labor diversity in education significantly enhances a firm's value added. Conversely, diversity in ethnicity and demographics induces negative effects on firm productivity. Hence, the negative effects, coming from communication and integration costs connected to a more culturally and demographically......Using a matched employer-employee dataset, we analyze how workforce diversity in cultural background, education and demographic characteristics affects productivity of firms in Denmark. Implementing a structural estimation of the firms' production function (Ackerberg et al., 2006) we find...

  5. Quality, Size and Performance of Audit Firms

    OpenAIRE

    Yahn-Shir Chen; Joseph Hsu; Mei-Ting Huang; Ping-Sen Yang

    2013-01-01

    This study examines the relations between audit quality, audit firm size, and financial performance. This study estimates audit quality of audit firms from human capital-related factors, such as educational level of auditors, work experience of auditors, and professional training. From the perspective of market segmentation, the sample is divided into three categories: national, regional, and local firms. Empirical results report a positive association between audit firm size and audit qualit...

  6. ICT and Household-Firm Relations

    OpenAIRE

    Lindbeck, Assar; Wikström, Solveig

    1999-01-01

    This paper discusses how ICT and emerging electronic commerce in consumer products influence the relative efficiency in production of households and firms, resulting in changes in the division of tasks between these two types of agents. Increased information and competence of households, in combination with stiffer competition among firms, will also increase the power of households relative to firms, at least in a long-term perspective with free entry of firms. Households will also get more p...

  7. Three Essays on Age and Firm Performance

    OpenAIRE

    Zeller, Jonas

    2014-01-01

    Old captains at the helm: Chairman age and firm performance Urs Waelchli and Jonas Zeller December, 2012 This paper examines whether the chairmen of the board (COBs) impose their life-cycles on the firms over which they preside. Using a large sample of unlisted firms we find a robust negative relation between COB age and firm performance. COBs age much like ‘ordinary’ people. Their cognitive abilities deteriorate and they experience significant shifts in motivation. Deteriorating cog...

  8. Capital structure and the firm under uncertainty

    OpenAIRE

    Broll, Udo; Wong, Kit Pong

    2003-01-01

    This paper examines the interplay between the real and financial decisions of the competitive firm `a la Sandmo. Besides output price uncertainty, the firm faces additional sources of risk which are aggregated into an additive background risk. We show that the firm always chooses its optimal debt-equity ratio to minimize the weighted average cost of capital, irrespective of the risk attitude of the firm and the incidence of the multiple sources of uncertainty. Even though the introduction of ...

  9. Human Capital and Wages in Exporting Firms

    DEFF Research Database (Denmark)

    Munch, Jakob Roland; Skaksen, Jan Rose

    2006-01-01

    This paper studies the link between a firms education level, export performance and wages of its workers. We argue that firms may escape intence competition in international markets by using high skilled workers to differentiate their products. This story is consistent with our empirical results....... an export wage premium, but it accrues to workers in firms with high skill intensities.Keywords: Exports, Wages, Human Capital, Rent Sharing, Matched Worker-Firm DataJEL Classification: J30, F10, I20...

  10. Capital Structure, Corporate Taxation and Firm Age

    OpenAIRE

    Pfaffermayr, Michael; Stöckl, Matthias; Winner, Hannes

    2008-01-01

    This paper analyses the relationship between corporate taxation, firm age and debt. We adapt a standard model of capital structure choice under corporate taxation, focusing on the financing and investment decisions a firm is typically faced with. Our model suggests that the debt ratio is positively associated with the corporate tax rate, and negatively with firm age. Further, we predict that the tax-induced advantage of debt is more important for older than for younger firms. To test these hy...

  11. The Equity Ownership Structure of Thai Firms

    OpenAIRE

    Wiwattanakantang, Yupana

    2001-01-01

    This paper examines the ownership structure of listed Thai firms in 1996. The ownership structure is concentrated. In 82.59 percent of the firms in the sample, the largest shareholders are also controlling shareholders. The controlling shareholders are mainly families. Foreign investors form the second largest group of controlling shareholders. More of the controlling shareholders use a simple ownership pattern to control the firms. Only in 21.27 percent of the firms, the controlling sharehol...

  12. International Taxation and Multinational Firm Location Decisions

    OpenAIRE

    Barrios Cobos, Salvador; Huizinga, Harry; Laeven, Luc; Gaëtan J.A. Nicodème

    2008-01-01

    Using a large international firm-level data set, we estimate separate effects of host and parent country taxation on the location decisions of multinational firms. Both types of taxation are estimated to have a negative impact on the location of new foreign subsidiaries. In fact, the impact of parent country taxation is estimated to be relatively large, possibly reflecting its international discriminatory nature. For the cross-section of multinational firms, we find that parent firms tend to ...

  13. Dynamic capabilities in small software firms

    OpenAIRE

    Kivelä, Marianne

    2007-01-01

    In this dissertation we study dynamic capabilities in small software firms. Small software firms find themselves in highly complex and turbulent environments that require dynamic capabilities to build, integrate and configure resources. While the literature describes a portfolio of such dynamic capabilities that can help firms to adapt to changing conditions, we could not find many definitions, models and studies on these capabilities suitable with particular focus on small software firms. Fu...

  14. Dynamic and quantitative assessment of blood coagulation using optical coherence elastography

    Science.gov (United States)

    Xu, Xiangqun; Zhu, Jiang; Chen, Zhongping

    2016-04-01

    Reliable clot diagnostic systems are needed for directing treatment in a broad spectrum of cardiovascular diseases and coagulopathy. Here, we report on non-contact measurement of elastic modulus for dynamic and quantitative assessment of whole blood coagulation using acoustic radiation force orthogonal excitation optical coherence elastography (ARFOE-OCE). In this system, acoustic radiation force (ARF) is produced by a remote ultrasonic transducer, and a shear wave induced by ARF excitation is detected by the optical coherence tomography (OCT) system. During porcine whole blood coagulation, changes in the elastic property of the clots increase the shear modulus of the sample, altering the propagating velocity of the shear wave. Consequently, dynamic blood coagulation status can be measured quantitatively by relating the velocity of the shear wave with clinically relevant coagulation metrics, including reaction time, clot formation kinetics and maximum shear modulus. The results show that the ARFOE-OCE is sensitive to the clot formation kinetics and can differentiate the elastic properties of the recalcified porcine whole blood, blood added with kaolin as an activator, and blood spiked with fibrinogen.

  15. Family firm research——A review

    Institute of Scientific and Technical Information of China (English)

    Qiang; Cheng

    2014-01-01

    This article reviews family firm studies in the finance and accounting literature,primarily those conducted using data from the United States and China. Family owners have unique features such as concentrated ownership, long investment horizon, and reputation concerns. Given the distinguishing features of family ownership and control, family firms face unique agency conflicts. We discuss the agency problems in family firms and review the findings of recent family firm studies. We call for more research to understand the unique family effects and encourage more research on Chinese family firms.Part I of the article discusses the fundaments of family firms: the prevalence of and the agency conflicts within family firms. Part II summarizes the findings of recent U.S. family firm studies. It reviews the evidence on the family firm premium(how, which, and when family firms are associated with a valuation premium), the manifestation of the agency conflict between majority and minority shareholders in family firms, earnings quality and corporate disclosure, and the determinants of family ownership and control. Part III discusses the prevalence and characteristics of Chinese family firms and reviews the findings of related studies. The article concludes with some suggestions for future research.

  16. Firm-Level Corruption in Vietnam

    DEFF Research Database (Denmark)

    Rand, John; Tarp, Finn

    This paper uses a unique panel dataset on firm-level corruption. It contains quantitative information on bribe payments by a sample of formal and informal Vietnamese firms. We show that bribe incidence is highly associated with firm-level differences in (i) visibility, (ii) sunk costs, (iii...

  17. Agility in a small software firm

    DEFF Research Database (Denmark)

    Schmidt, Thomas; Mathiassen, Lars

    2009-01-01

    Small software firms are vulnerable to environmental uncertainty. While agile methods and other technologies offer suggestions to this challenge, we know little about how these firms combine project and firm level capabilities to effectively respond to changes. On this backdrop, we examine a small...

  18. Reputational penalties to firms in antitrust investigations

    NARCIS (Netherlands)

    Broek, van den S.; Kemp, R.G.M.; Verschoor, W.F.C.; Vries, de A.

    2012-01-01

    We estimate the impact of legal penalties imposed on Dutch listed firms targeted by competition authorities from 1998 to 2008 on a firm's stock market value. On average, firms lose 2.3 percent of their market values when an antitrust investigation is uncovered. This corresponds to a total value loss

  19. Decomposing Firm-level Sales Variation

    DEFF Research Database (Denmark)

    Munch, Jakob Roland; Nguyen, Daniel Xuyen

    We measure the contribution of firm-specific effects to overall sales variation within a destination and find it remarkably low. Our empirical decomposition is structurally motivated by a heterogeneity model of exporting involving destination-specific, firm-specific, and firm-destination-specific...

  20. New Firm Growth: Exploring Processes and Paths

    NARCIS (Netherlands)

    E. Garnsey; F.C. Stam (Erik); P. Heffernan; O. Hugo

    2003-01-01

    textabstractThis paper provides a new methodology for the diachronic study of new firm growth, theoretically grounded in the work of Penrose (1995). We show that a model of firm growth as an unfolding process makes possible draw simple, measurable inferences from firm level to aggregate evidence on

  1. The Dividend Policy of German Firms

    NARCIS (Netherlands)

    Andres, C.; Betzer, A.; Goergen, M.; Renneboog, L.D.R.

    2008-01-01

    German firms pay out a lower proportion of their cash flows, but a higher proportion of their published profits than UK and US firms. We estimate partial adjustment models and report two major findings. First, German firms base their dividend decisions on cash flows rather than published earnings as

  2. The Dividend Policy of German Firms

    NARCIS (Netherlands)

    Andres, C.; Betzer, A.; Goergen, M.; Renneboog, L.D.R.

    2008-01-01

    Abstract: German firms pay out a lower proportion of their cash flows, but a higher proportion of their published profits than UK and US firms. We estimate partial adjustment models and report two major findings. First, German firms base their dividend decisions on cash flows rather than published e

  3. Independent Directors Human Capital and Firm Internationalization

    OpenAIRE

    Hsiang-Lan Chen

    2014-01-01

    This study examines the effect of independent directors? human capital (independent directors? educational level, CEO experience and international experience) on firms? decisions toward internationalization. Using a panel of electronics firms in Taiwan, the results show that independent directors? CEO experience and international experience are positively and significantly related to firm internationalization. Independent directors? educational level is positively, but not significantly, asso...

  4. HRM in professional service firms

    DEFF Research Database (Denmark)

    Jørgensen, Frances

    2012-01-01

    Professional service firms (PSFs) present HR professionals with a number of unique challenges, as they share characteristics of both service and knowledge intensive organizations. While many of these firms are relying on High Commitment Work Practices (HCWPs) to enhance critical employee behaviors...... such as service quality and turnover, the analysis presented in this paper raises questions about traditional understandings of commitment in professional service environments. In particular, data from three Danish financial investment PSFs suggest that employees are more committed to developing and...... promoting their own professions than to the organization itself, which has important implications for the way in which HCWPs are designed and utilized. In addition, the focus of HCWP research has favored the use of social exchange theory as an underpinning framework for considering the impact of HR...

  5. Simple models of firms emergence

    Science.gov (United States)

    Weisbuch, Gérard; Mangalagiu, Diana; Ben-Av, Radel; Solomon, Sorin

    2008-09-01

    We present a dynamical model of the emergence of firms as opposed to a flat labour market where entrepreneurs would recruit workers for each business opportunity. The model uses a preferential choice of partners based on previous collaborations experience. A sharp transition in the parameter space separates an ordered regime, where preferential links establish, from a disordered regime corresponding to a fast turnover of employees.

  6. Do IPO Firms Manage Earnings?

    OpenAIRE

    Moustafa Fadl

    2013-01-01

    IPO literature documents that IPO firms experience a decline in returns after listing. This paper investigates that phenomena and tries to find reasons for it. Earning management studies report that if companies have a high level of discretionary accruals, then those companies engage in earnings management. This paper connects these two literature branches together by using a third part of literature, which is market timing and market efficiency. I built a dummy variable DTIMERS that takes th...

  7. Canadian Firm and Job Dynamics

    OpenAIRE

    Ravi Balakrishnan

    2008-01-01

    To understand better Canada's smooth reallocation of labor in response to the recent commodity price boom, but seemingly poor productivity performance, this paper examines job and firm dynamics in Canada relative to the United States. Overall, it finds that while Canada's labor market efficiency seems comparable to that of the United States, product market rigidities appear to be reducing Canada's capacity for creative destruction, hence undermining productivity growth.

  8. Constitutional orders in multinational firms

    DEFF Research Database (Denmark)

    Hull Kristensen, Peer; Morgan, Glenn

    Multinationals are faced with the problem of how to coordinate different actors and stop `fiefdoms' emerging that inhibits the achievement of transnational cooperation? We identify this as a problem of `constitutional ordering' in the firm. Drawing on Varieties of Capitalism approaches, we explore...... how multinationals from different contexts seek to create constitutional orders. We argue that the models which exist appear to be destructive of coordination. We explore the implications for MNCs....

  9. Why Firms Purchase Property Insurance?

    OpenAIRE

    Daniel Aunon-Nerin; Paul Ehling

    2007-01-01

    We investigate whether corporate finance incentives aect the extent of corporate hedging with property insurance. Using a database that contains detailed insurance information, we show that rms buy property insurance to reduce the expected costs of distress. Further, we document a scale effect: large rms purchase less insurance per unit of property. This is consistent with the notion that expected bankruptcy costs fall as firm size increases. We also show that the dividend payout ratio exerts...

  10. Innovation in small food firms

    OpenAIRE

    Avermaete, Tessa

    2012-01-01

    Internationalisation of the world food market, structural changes in the food chain, changing consumption patterns and the strengthening of food regulation lie on the basis of the fast developments in the food and drink industry. Facing increased competition, small food firms are generally limited in exploiting economies of scale. Alternatively, they are more likely to seek for strategies that are based on the introduction of new products, optimising processing, the reorganisation of manageme...

  11. Financial Needs of Internationalized Firms

    OpenAIRE

    Federica Sist

    2014-01-01

    This paper is a conceptual work on financial needs generated by the internationalization process of firms, especially non-large ones, in their life cycle. The forms of internationalization considered are trade (export and import) and foreign direct investment (FDI). A careful analysis of the literature reveals a dearth of research on this specific topic; in fact, the financial side of international business theory is poorly treated and the study of financial needs is often included in other t...

  12. Institutions, Firms and Economic Growth

    OpenAIRE

    Jane Frances

    2004-01-01

    This paper reviews the literature on institutions and explores the ways in which institutions can influence economic growth, with a particular focus on how institutions affect the use that firms make of human capital to improve their productivity. It discusses the influence of underlying institutions, such as law and order and secure property rights, on the general environment within which the economic activities of production and exchange takes place. It also explores the influence of activi...

  13. Optimization of firm's tax liability

    OpenAIRE

    Švihálek, Pavel

    2012-01-01

    The thesis is divided in two basic parts. The first part includes structure of the tax system in the Czech Republic, explanation of tax definitions and characteristics of Czech tax system. The goal of the first part is to clarify the tax system, tax base calculation and factors that influence its amount. The second part is structured more practically and should offer several possibilities of how to optimize the firm's tax liability, with focus on the corporate income tax.

  14. Training in Chinese Small Firms

    OpenAIRE

    Dai, Zhejun

    2007-01-01

    The dissertation aims to review the currently predominant literature on the factors influencing the training in small business in the industrialized Western economies and to carry out empirical investigation on the determinants of training in Chinese small business and then analyze whether the Western-based literature is consistent with the practices of training in Chinese small firms. In addition, relevant problems with training in small business are presented and recommendations on how to r...

  15. Multinational Firms and Heterogeneous Workers

    OpenAIRE

    Mario Larch; Wolfgang Lechthaler

    2008-01-01

    In the presence of increasing specialization of workers it becomes more and more difficult for firms to find the most suitable workers. In such an environment a multinational corporation has an advantage because it can exchange workers between plants in different countries. In this way it can draw on a larger labor market pool, reducing the mismatch of its workforce. This paper analyzes the consequences of this advantage for production, employment and, most prominently, wages. We are able to ...

  16. Unions, training and firm performance

    OpenAIRE

    Addison, John T.; Belfield, Clive R.

    2007-01-01

    The present paper uses a combination of workplace and linked employee-workplace data from the 1998 Workplace Employee Relations Survey and the 2004 Workplace Employment Relations Survey to examine the impact of unions on training incidence, training intensity/coverage, and training duration. It also examines the impact of unions and training on earnings and a measure of establishment labour productivity. In addition, the implications of training for the firm's bottom line are evaluated. Union...

  17. Communication in an "Officeless firm"

    OpenAIRE

    Burchell, Brendan J.; LAI, YI

    2008-01-01

    New technologies permit new types of organisations. This article describes and analyses one such organisation, an "officeless firm", where all employees work from their own homes and there is no central office. Drawing upon observations and interviews, the modes of communication and the nature of the interpersonal relationships that have permitted this organisation to succeed are described, along with the challenges that face this organisation in the future as it attempts to grow.

  18. TYPOLOGY OF KNOWLEDGE-BASED FIRMS - INFLUENCES ON THE VALUE OF THE FIRM

    OpenAIRE

    Bogdan Marza

    2009-01-01

    As Michael Porter states that there are three main stages of economic competitiveness that a nation may go through, so we can say by analogy that there are three stages of firm competitiveness: firms based on classical inputs, investment firms and firms based on innovation and knowledge - modern organizations.

  19. Investment financing in cooperative firms

    Directory of Open Access Journals (Sweden)

    Gaetano Cuomo

    2015-04-01

    Full Text Available By general agreement, one of the main obstacles to the growth of producer cooperatives is difficult investment financing, due to inadequate Capitalisation levels and the resulting inability to lodge sufficient collateral with lenders. Moreover, worker-owned firms are considered not very reliable because they suffer from problems of moral hazard and insufficient commitment. Unfortunately, the literature on this issue is not extensive and has weaknesses that are highlighted in the paper. By means of its critical analysis, it is possible to provide evidence that the funding difficulties caused by the particular structure of cooperative firms can be effectively tackled by creating an institutional framework within which cooperatives would be offered a wider range of organizational options comparable to those open to traditional enterprises. Finally, it is proved that the willingness of the members to fund the operations of their cooperative with loan capital may not be enough to mobilize external credit. For member financings to persuade potential providers of funds to place trust in a firm, third-party claims must necessarily qualify as senior debt and be repaid before the claims of the partners are settled.

  20. Mobility Enhancement of Red Blood Cells with Biopolymers

    Science.gov (United States)

    Tahara, Daiki; Oikawa, Noriko; Kurita, Rei

    2016-03-01

    Adhesion of red blood cells (RBC) to substrates are one of crucial problems for a blood clot. Here we investigate the mobility of RBC between two glass substrates in saline with polymer systems. We find that RBCs are adhered to the glass substrate with PEG, however the mobility steeply increases with fibrinogen and dextran, which are biopolymers. We also find that the mobility affects an aggregation dynamics of RBCs, which is related with diseases such as influenza, blood clot and so on. The Brownian motion helps to increase probability of contact with each other and to find a more stable condition of the aggregation. Thus the biopolymers play important roles not only for preventing the adhesion but also for the aggregation.

  1. Founder Control,Ownership Structure and Firm Value:Evidence from Entrepreneurial Listed Firms in China

    Institute of Scientific and Technical Information of China (English)

    Lijun Xia

    2008-01-01

    In emerging markets, the deviation between the ultimate controlling shareholders’ voting rights and their cash flow rights(hereafter "DVC") in the listed firms is quite prevalent. DVC could be introduced due to the ultimate controlling shareholders’ opportunistic incentives, as well as by their incentives to improve firm efficiency. This study uses 229 listed firms ultimately controlled by individuals or families(hereafter "entrepreneurial firms") for 2004 in China, to investigate the effect of DVC on firm value and to determine whether it is different between founder and non-founder controlled firms. We find that DVC has a positive effect on firm value for founder controlled firms. This result implies that investors believe that their interests are better protected by founder controlled firms than by non-founder controlled firms.

  2. Essays on Firm Behavior in Developing Economies

    Science.gov (United States)

    Abeberese, Ama Baafra

    The performance of firms is central to growth in developing economies. A burgeoning literature within development economics seeks to understand the behavior of firms in developing countries and the constraints to their performance. This dissertation explores two types of constraints---infrastructure-related constraints and trade-related constraints---faced by manufacturing firms in developing countries. Despite the widely acknowledged importance of infrastructure for economic growth, there has been relatively little research on how infrastructure affects the decisions of firms. Electricity, in particular, is commonly cited by firms in developing countries as a major obstacle to their performance. In the first two chapters, I analyze the responses of firms to two types of electricity constraints, namely electricity prices and electricity shortages. Chapter 1 provides evidence on how electricity prices affect a firm's industry choice and productivity growth using data on Indian manufacturing firms. I construct an instrument for electricity price as the interaction between the price of coal paid by power utilities, which is arguably exogenous to firm characteristics, and the initial share of thermal generation in a state's total electricity generation capacity. I find that, in response to an exogenous increase in electricity price, firms reduce their electricity consumption and switch to industries with less electricity-intensive production processes. I also find that firm output, machine intensity and labor productivity decline with an increase in electricity price. In addition to these level effects, I show that firm output and productivity growth rates are negatively affected by high electricity prices. These results suggest that electricity constraints faced by firms may limit a country's growth by leading firms to operate in industries with fewer productivity-enhancing opportunities. Chapter 2 examines the impact of electricity shortages on firm investment. I

  3. Firm Leverage and the Financial Crisis

    OpenAIRE

    Altunok, Fatih; Oduncu, Arif

    2013-01-01

    The firm growth dynamics is an important topic since the growth performance of firms is the main source of the economic growth in countries. Generally, crises produce a sharp decline in firms’ growth and this leads to a decline in both the level of employment and the income of households. This paper focuses on the role of firm leverage on the growth performance of the firm during the global financial crisis. We investigate whether the firms that experienced a large leverage increase before th...

  4. Do Treasure Islands Create Firm Value?

    DEFF Research Database (Denmark)

    Lai, Tat-kei; Ng, Travis

    abnormal return (CAR) among the sampled firms, corresponding to about £532 million in market capitalization. The firms of stronger corporate governance registered a stronger reduction in CAR. A simple linear extrapolation suggests that the firm value contributed by tax havens can be as much as £31 billion.......They do! Otherwise, their use would not have been so prevalent among firms. How much firm value they create, however, is still an open question. Exploiting a political event in the U.K. that suddenly raised the cost of using tax havens, we find that there was a 0.87% reduction in cumulative...

  5. Competition, Firm Turnover and Productivity Growth

    OpenAIRE

    Gu, Wulong; Baldwin, John R.

    2006-01-01

    This paper investigates the extent to which productivity growth is the result of firm turnover as output is shifted from one firm to another, driven by the competitive process. Turnover occurs as some firms gain market share and others lose it. Some of the resulting turnover is due to entry and exit. Another part arises from growth and decline in incumbent continuing firms. This paper proposes a method for measuring the impact of firm turnover on productivity growth and shows that it is far m...

  6. Endogenous Markups, Firm Productivity and International Trade:

    DEFF Research Database (Denmark)

    Bellone, Flora; Musso, Patrick; Nesta, Lionel;

    In this paper, we test key micro-level theoretical predictions ofMelitz and Ottaviano (MO) (2008), a model of international trade with heterogenous firms and endogenous mark-ups. At the firm-level, the MO model predicts that: 1) firm markups are negatively related to domestic market size; 2......) markups are positively related to firm productivity; 3) markups are negatively related to import penetration; 4) markups are positively related to firm export intensity and markups are higher on the export market than on the domestic ones in the presence of trade barriers and/or if competitors on the...

  7. Performance of Patenting Firms in Danish Manufacturing

    DEFF Research Database (Denmark)

    Madsen, Erik Strøjer; Smith, Valdemar; Nielsen, Anders Østergaard

    2000-01-01

    Most countries focus on industries with high technology and the governments grant subsidies to innovating firms. However, there has been remarkable few studies of the performance of innovative firms or industries. This study examines the performance of patent active firms compared to the non-patenting...... firms within the manufacturing sector in Denmark. Performance is measured both by growth in employment as well as in the return on equity and profit share in turnover. The results suggest that differences in performance of patenting and non-patenting firms are very small, which questions the political...

  8. The Relationship between Offshoring Strategies and Firm Performance: Impact of innovation, absorptive capacity and firm size

    OpenAIRE

    Roza-van Vuren, Marja

    2011-01-01

    textabstractHow do offshoring strategies impact firm performance? And how are innovation, absorptive capacity and firm size influencing this relationship? This research investigates how firms of varying size, well-established firms and growing firms may profit from relocating business activities to foreign locations. Offshoring strategies are conceptualized as consisting of both organizational attributes – i.e. function offshored, governance mode and location – and strategic attributes – i.e....

  9. The Division of Labor within Firms, Optimal Entry, and Firm Productivity

    OpenAIRE

    Koji Shintaku

    2014-01-01

    Constructing an intra-industry trade model with division of labor within firms, this paper shows that opening up to trade improves firm productivity. Firms choose the number of markets they export. Optimal entry conditions for export markets rule out loss from opening up to trade. Under fixed export costs, opening up to trade makes some firms exit and concentrates labor to surviving firms through recruiting process and induces the division of labor. An increase in the number of markets induce...

  10. Quality Employment and Firm Performance Evidence from Indian Firm-Level Data

    OpenAIRE

    Amoranto, Glenita; Chun, Natalie

    2011-01-01

    We investigate the characteristics of manufacturing firms in India that generate better quality employment and the relationship between quality employment and firm performance using multiple measures of employment quality. Larger firms tend to generally provide better quality employment opportunities even after controlling for aspects related to employee skills. The organizational structure of firms matters, with government, private, and cooperative firms generally in terms of providing highe...

  11. Board Composition And Firm Performance In Spanish Non-Listed Firms

    OpenAIRE

    Arosa de la Torre, Blanca; Txomin Iturralde Jainaga; Amaia Maseda Garcia

    2010-01-01

    In the context of ownership concentration, the aim of this study is to analyse the usefulness of the board of directors as an internal control mechanism and, in the case of family firms, also consider the generational effect. We examined the relation between firm performance and outside directors in SME non-listed family and non-family firms. Our findings show the existence of a negative impact of outside directors on firm performance in family firms, and the clear difference in b...

  12. The theory of the firm. Vol. 3

    DEFF Research Database (Denmark)

    Firms have for a long time been part of the explanatory set-up of economics. However, it is only recently that economists have felt the need for an economic theory addressing: why firms are different; why firms exist; what determines their boundaries relative to "the market"; and what determines...... their internal organization. This collection documents the rise of the modern theory of the firm during the last two to three decades. It reprints classic writings from a diversity of perspectives, including not only contractual theories of the firm, but also knowledge-based theories and theories of the...... firm as an information processor. In addition, the collection features perspectives from business strategy and business history as well as methodological and doctrinal historical perspectives. Including over 60 classic papers, these volumes collect together contributions on the theory of the firm...

  13. Women in Top Management and Firm Performance

    DEFF Research Database (Denmark)

    Smith, Nina; Smith, Valdemar; Verner, Mette

    The purpose of this study is to present new evidence on the relationship between gender diversity in management and firm performance. According to corporate governance literature, board diversity is expected to affect firm performance. Using a large data set with more than 10000 time-observations......The purpose of this study is to present new evidence on the relationship between gender diversity in management and firm performance. According to corporate governance literature, board diversity is expected to affect firm performance. Using a large data set with more than 10000 time...... on how top CEOs are defined and on the method of estimation of the model. Next, the results point towards a positive influence on firm performance of the staff representation in the supervisory board of the firm but more women representing the shareholders in the supervisory board of the firm seems...

  14. Ion suppression from blood collection devices

    DEFF Research Database (Denmark)

    Hasselstrøm, Jørgen Bo; Sejr Gothelf, Aase

    The aim of the study was to examine the variation in ion suppression in ultra high pressure liquid chromatography tandem mass spectrometry (UHPLC-MS-MS) methods when using different blood collection devices. Three different methods measuring 18 antidepressants and antipsychotics in total were...... studied. The blood collection devices were all designed to activate clot formation. They were made of glass with or without silicone coating or plastic containing silicate particles, thrombin or polystyrene particles coated with kaolin. The blood collection devises Venoject and Venosafe were supplied from...... Terumo, S-monovette from Sarstedt, Vacuette from Greiner Bio-One and three BD Vacutainer serum tubes from BD. These seven different blood collection devices were used to withdraw blood from five healthy drug free donors (n=35) in random order. The samples were centrifuged and serum from each sample...

  15. Like milk or wine : does firm performance improve with age?

    OpenAIRE

    Coad, Alex; Segarra Blasco, Agustí; Teruel Carrizosa, Mercedes

    2010-01-01

    Our empirical literature review shows that little is known about how firm performance changes with age, presumably because of the paucity of data on firm age. For Spanish manufacturing firms, we analyse the firm performance related to firm age between 1998 and 2006. We find evidence that firms improve with age, because ageing firms are observed to have steadily increasing levels of productivity, higher profits, larger size, lower debt ratios, and higher equity ratios. Furthermore, older firms...

  16. Blood coagulation profiling in patients using optical thromboelastography (OTEG) (Conference Presentation)

    Science.gov (United States)

    Tripathi, Markandey M.; Tshikudi, Diane M.; Hajjarian, Zeinab; Van Cott, Elizabeth M.; Nadkarni, Seemantini K.

    2016-02-01

    Impaired blood coagulation is often associated with increased postoperative mortality and morbidity in cardiovascular patients. The capability for blood coagulation profiling rapidly at the bedside will enable the timely detection of coagulation defects and open the opportunity for tailoring therapy to correct specific coagulation deficits Optical Thromboelastography (OTEG), is an optical approach to quantify blood coagulation status within minutes using a few drops of whole blood. The goal of the current study is to evaluate the diagnostic accuracy of OTEG for rapid coagulation profiling in patients. In OTEG, temporal laser speckle intensity fluctuations from a drop of clotting blood are measured using a CMOS camera. To quantify coagulation status, the speckle intensity autocorrelation function is measured, the mean square displacement of scattering particles is extracted, and viscoelastic modulus (G), during coagulation is measured via the generalized Stokes-Einstein relation. By quantifying time-resolved changes in G, the coagulation parameters, reaction time (R), clot progression time (K), clot progression rate (Angle), and maximum clot strength (MA) are derived. In this study, the above coagulation parameters were measured using OTEG in 269 patients and compared with standard mechanical Thromboelastography (TEG). Our results showed a strong correlation between OTEG and TEG measurements for all parameters: R-time (R=0.80, pcoagulation status to potentially improve clinical capability for identifying impaired coagulation in cardiovascular patients at the point of care.

  17. Use of proteomics for validation of the isolation process of clotting factor IX from human plasma

    OpenAIRE

    Clifton, James; Huang, Feilei; Gaso-Sokac, Dajana; Brilliant, Kate; Hixson, Douglas; Josic, Djuro

    2009-01-01

    The use of proteomic techniques in the monitoring of different production steps of plasma-derived clotting factor IX (pd F IX) was demonstrated. The first step, solid-phase extraction with a weak anion-exchange resin, fractionates the bulk of human serum albumin (HSA), immunoglobulin G, and other non-binding proteins from F IX. The proteins that strongly bind to the anion-exchange resin are eluted by higher salt concentrations. In the second step, anion-exchange chromatography, residual HSA, ...

  18. Firm-Specific Strategic Advantages and Foreign Direct Investments Behavior of Firms: The Case of Japanese Semiconductor Firms

    OpenAIRE

    Yui Kimura

    1989-01-01

    We examine the effects of firm-specific strategic advantages on the FDI behavior of Japanese semiconductor firms. We investigate the strategic advantages necessary for undertaking FDI in this industry, and show that these advantages are systematically associated with the variation in FDI behavior. We identify technological innovation, a broad product line, and vertical linkages with down stream businesses as sources of such strategic advantages. We also show that size of the firm influences i...

  19. Use of blood and blood products.

    Science.gov (United States)

    Hunt, E; Wood, B

    1999-11-01

    It is sometimes necessary for the practitioner to transfuse the ruminant with whole blood or plasma. These techniques are often difficult to perform in practice, are time-consuming, expensive, and stressful to the animal. Acute loss of 20% to 25% of the blood volume will result in marked clinical signs of anemia, including tachycardia and maniacal behavior. The PCV is only a useful tool with which to monitor acute blood loss after intravascular equilibration with other fluid compartments has occurred. An acutely developing PCV of 15% or less may require transfusion. Chronic anemia with PCV of 7% to 12% can be tolerated without transfusion if the animal is not stressed and no further decline in erythrocyte mass occurs. Seventy-five percent of transfused bovine erythrocytes are destroyed within 48 hours of transfusion. A transfusion rate of 10 to 20 mL/kg recipient weight is necessary to result in any appreciable increase in PCV. A nonpregnant donor can contribute 10 to 15 mL of blood/kg body weight at 2- to 4-week intervals. Sodium citrate is an effective anticoagulant, but acid citrate dextrose should be used if blood is to be stored for more than a few hours. Blood should not be stored more than 2 weeks prior to administration. Heparin is an unsuitable anticoagulant because the quantity of heparin required for clot-free blood collection will lead to coagulation defects in the recipient. Blood cross-matching is only rarely performed in the ruminant. In field situations, it is advisable to inject 200 mL of donor blood into the adult recipient and wait 10 minutes. If no reaction occurs, the rest of the blood can probably be safely administered as long as volume overload problems do not develop. Adverse reactions are most commonly seen in very young animals or pregnant cattle. Signs of blood or plasma transfusion reaction include hiccoughing, tachycardia, tachypnea, sweating, muscle tremors, pruritus, salivation, cough, dyspnea, fever, lacrimation, hematuria

  20. "Blood" in D.H. Lawrence and O. Wilde

    OpenAIRE

    中山, 本文; Motofumi, NAKAYAMA

    2015-01-01

    Lawrence and Wilde found something special in "blood." Lawrence had a firm belief in "blood" symbolizing primitive "daemonic" energy. Lawrence's blood operates as energy to encourage one to transcend individuality and acquire "a greater life." With profound insight, he asserts that an invisible world of "blood-consciousness" underlies the visible world. Wilde too stresses "blood" as seen in "The Nightingale and the Rose," "The Happy Prince." or "The Selfish Giant." The "blood," which is insep...

  1. An Aspirational Community Theory of the Firm

    DEFF Research Database (Denmark)

    Li, Xin

    All of the three major theories of the firm, i.e., the transaction cost theory, knowledge-based theory and the entrepreneurship theory, offer some insightful analyses of the nature of the firm. However, they all have limitations and weaknesses in answering the fundamental question of the existence...... end, we propose an aspirational community theory of the firm (ACT) as a candidate theory by conceptualizing the firm as an aspirational community, the core of which is a group of like-minded people sharing similar or same aspiration/vision. To explain the existence of the firm, we make a distinction...... between contractual labor and aspirational labor, the former being defined as services provided by a laborer in fulfillment of a contract while the latter as services provided by a laborer in pursuit of an aspiration; and argue that firms exist because while the market may be effective and efficient for...

  2. Job Creation by Firms in Denmark

    DEFF Research Database (Denmark)

    Ibsen, Rikke Falkner; Westergård-Nielsen, Niels

    Denmark lost 186,000 jobs in the private sector. The question is where and how could these jobs be recreated. Are these issues specific to industries or are they universal? The data used is register data on workplaces and firms for the period 1980-2007. The base unit of data is the workplace. The company......In this paper we will look at job creation and destruction in firms. We will answer the question if it is the large companies that create jobs, while the smaller companies are contributing much less. Or is it the young companies that create jobs? And who destroys the most jobs? In the crisis...... time. A complication here is that firms switch ID over time because of change of ownership, mergers and divisions. Data must be corrected so that these administrative issues will not affect the survival of firms. The data are used in a way where we can cover firm birth and firm death, spin...

  3. Workforce reduction and firm performance: Evidence from French firm data

    OpenAIRE

    Reynaud, Bénédicte

    2010-01-01

    A partir d'une base de données annuelles d'entreprises françaises (1994-2000), cet article étudie les déterminants d'une réduction d'emploi des entreprises cotées et non cotées et leurs conséquences sur la performance des firmes. Nous aboutissons à deux conclusions. D'une part, la réduction d'emploi apparaît comme une stratégie défensive en réponse à un choc économique négatif. Cependant, les entreprises cotées anticipent mieux que les autres la décision de réduire l'emploi. D'autre part, les...

  4. Taxing the Financially Integrated Multinational Firm

    OpenAIRE

    Johannesen, Niels

    2010-01-01

    This paper develops a theoretical model of corporate taxation in the presence of financially integrated multinational firms. Under the assumption that multinational firms at least partly use internal loans to finance foreign investment, we find that the optimal corporate tax rate is positive from the perspective of a small, open economy. This finding contrasts the standard result that the optimal source based capital tax is zero. Intuitively, to the extent that multinational firms finance inv...

  5. International working capital practices of Ghanaian firms

    OpenAIRE

    J. Abor

    2005-01-01

    International working capital management is important to firms frequently operating in the international market. This article investigates the international working capital practices of top Ghanaian firms involved in international trade. The objective of the study is to ascertain the extent to which Ghanaian firms use international working capital management vehicles. The article focuses on two main areas of international working capital management; international cash management and int...

  6. Working Capital Management and Firm Listing Status

    OpenAIRE

    Seraina Anagnostopoulou

    2012-01-01

    This study comparatively examines the determinants of working capital management for listed vs. unlisted firms, and assesses the impact of this policy on profitability by focusing on the cash conversion cycle, a commonly used measure of working capital management. By using a large UK public and private firm sample, it is found that private firms have significantly lower cash conversion cycles than their public counterparts, and that traditional determinants of the cycle significantly differ b...

  7. Accounting Firms: Global Spread with Limited Transnationalization

    OpenAIRE

    Jochen Zimmermann; Jan-Christoph Volckmer

    2012-01-01

    As financial markets have increasingly globalised, the regulatory framework is still nationally fragmented. One core regulatory element is the provision of assurance services by accounting firms. The Big 4 - the leading international providers of audit services Ð are not as international as are accounting standards or their clients. The paper traces three facets of the transnationalization of accounting firms: explanations for internationalization rooted in the theory of the firm, their modes...

  8. Nearly Optimal Pricing for Multiproduct Firms

    OpenAIRE

    Chenghuan Sean Chu; Phillip Leslie; Alan Sorensen

    2008-01-01

    In principle, a multiproduct firm can set separate prices for all possible bundled combinations of its products (i.e., "mixed bundling"). However, this is impractical for firms with more than a few products, because the number of prices increases exponentially with the number of products. In this study we show that simple pricing strategies are often nearly optimal -- i.e., with surprisingly few prices a firm can obtain 99% of the profit that would be earned by mixed bundling. Specifically, w...

  9. Knowledge production and firm growth in Brazil

    OpenAIRE

    João Alberto De Negri; Luiz Esteves; Fernando Freitas

    2007-01-01

    The aim of this study is to gauge the impact of the production of knowledge on the accumulation of fixed capital in Brazil. The hypothesis is that investment in R&D causes investment in fixed capital in Brazilian industrial firms. The empirical estimates rest on an IPEA database for information on firms and the workers linked to these firms during the period 1996-2003 and on the National Innovation Survey (PINTEC) for information on technological development. In the article, various estimates...

  10. Corporate Governance, Firm Risk and Shareholder Value

    OpenAIRE

    Wolfswinkel, Michiel

    2013-01-01

    textabstractThis dissertation consists of three studies in the field of corporate governance. The research examines the impact of the way Dutch firms are managed and controlled on risk characteristics and the implications for shareholder value. The first study examines the relation between board interlocks and firm risk. In particular, we measure the effect of supervisory directors’ connectivity on firm risk. We find yet unknown aspects of connectivity and based on our findings the validity o...

  11. BOARD INFLUENCE ON A FIRM'S INTERNATIONALIZATION

    OpenAIRE

    Barroso, Carmen; Villegas, Mª Mar; Pérez-Calero, Leticia

    2011-01-01

    Abstract Manuscript Type: Empirical Research Question/Issues: The resource-based view of the firm may provide the theoretical explanation as to how boards can be a source of firm competitive advantage. Directors? experience, knowledge, expertise are valuable, rare, inimitable and non-substitutable resources that making up the board potential. These resources must be integrated with others firm resources in strategic processes through dynamics of relations. Research Findings/...

  12. Female directors, key committees, and firm performance

    OpenAIRE

    Green, Colin; Homroy, Swarnodeep

    2015-01-01

    There is pressure to increase female representation on corporate boards. A number of studies have found no, or in some cases a negative, effect of female representation on boards and firm performance. We demonstrate robust positive and economically meaningful effects on firm performance of female representation on European boards. Moreover, while previous work has considered female representation broadly, we focus on membership of committees involved explicitly in firm governance. We demonstr...

  13. Bank ties and firm performance in Japan

    OpenAIRE

    McGuire, Patrick

    2015-01-01

    Since the mid-1990s, major Japanese banks have sold off a significant portion of their holdings of corporate equity. Using information on the identity of Japanese firms' top 10 shareholders, this paper explores the process of banks' equity disposal. There is some evidence that, after FY2001, banks' sales of equity accelerated, even holdings in firms for which the bank served as the main bank. However, affiliation with a main bank - proxied by firm-bank loan and shareholding ties - continues t...

  14. How does firm performance influence market orientation?

    DEFF Research Database (Denmark)

    Sørensen, Hans Eibe; Stieglitz, Nils

    This paper contributes by investigating how firm performance influences its market orientation. We draw on the aspiration-level model from the behavioral theory of the firm to develop testable propositions that substantiate and extend prior market orientation research. Specifically, we address ho...... performance influences firms' market-oriented search behavior (responsive or proactive) and the allocation of attention (customer and competitor orientation) as well as the formation of aspiration levels. Research and managerial implications are discussed....

  15. Why Did ?Zombie? Firms Recover in Japan?

    OpenAIRE

    Shin-ichi Fukuda; Jun-ichi Nakamura

    2010-01-01

    The Japanese economy experienced prolonged recessions during the 1990s. Previous studies suggest that evergreen lending to troubled firms known as "zombie firms" distorted market discipline in terms of stabilizing the Japanese economy and caused significant delays in the economy's recovery. However, the eventual bankruptcy of zombies was rare. In fact, a majority of the "zombie" firms substantially recovered during the first half of the 2000s. The purpose of this paper is to investigate why z...

  16. Endogenous Trade Policy with Heterogeneous Firms

    OpenAIRE

    Jennifer Abel-Koch

    2013-01-01

    The present paper modifies the \\Protection for Sale" model of Grossman and Helpman (1994) to account for heterogeneous firms lobbying for non-tariff barriers to trade, such as technical standards or certification requirements. They raise the fixed costs of market access for both domestic producers and foreign exporters, force the least efficient firms to exit and shift profits to the most efficient firms. Non-tariff barriers to trade shift profits both within and across countries, but not nec...

  17. Globalization, occupational restructuring and firm performance

    OpenAIRE

    Maliranta, Mika

    2013-01-01

    In this study, the patterns of occupational restructuring and their micro-level mechanisms are examined by applying standard measures of job and worker flows at the occupation and firm levels using longitudinal employeremployee data from the Finnish business sector for the years 2000-2006. Special attention is given to determining how global firms (i.e., multinational enterprises and offshoring firms) contribute to occupational restructuring and to establishing the role of occupational struct...

  18. Tax planning, corporate governance and firm value

    OpenAIRE

    Abdul Wahab, Nor Shaipah; Holland, Kevin

    2012-01-01

    Tax planning by firms is a highly significant activity. After audit fees, tax related services are the largest source of fee income for UK accounting firms. When viewed in terms of its impact, tax planning is the major source of the corporation tax gap amongst large firms (HMRC, 2010). Although traditionally tax planning has been viewed as benefiting shareholders via increased after tax earnings, more recently the underlying motivation has been questioned. Desai and Dharmapala (2006) argu...

  19. The Organization of Knowledge in Multinational Firms

    OpenAIRE

    Gumpert, Anna

    2015-01-01

    This paper provides the first in-depth study of the organization of knowledge in multinational firms. The paper develops a theoretical model that studies how firms optimally split knowledge between their headquarters and their production plants if communication costs impede the access of production plants to headquarter knowledge. The paper assumes that the foreign plants of multinational firms face higher communication costs with headquarters than their domestic plants, and shows that multin...

  20. Stock option incentives and firm performance

    OpenAIRE

    Hillegeist, Stephen A.; Peñalva, Fernando

    2004-01-01

    This paper analyzes the performance consequences of employee stock options for a broad sample of firms during the period 1996-1999. Our tests are performed separately for the top 5 executives and all other employees. We estimate the expected level of option incentives based on each firm's economic characteristics. We examine the association between the unexpected level of option incentives and firm performance as measured by future abnormal returns, future return on assets, and current and fu...

  1. Firm Performance and Board Committee Structure.

    OpenAIRE

    Klein, April

    1998-01-01

    This article demonstrates a linkage between firm performance and board composition by examining the committee structure of boards and the directors' roles within these committees. Consistent with previous studies, I find little association between firm performance and overall board composition. However, by going into the inner workings of the board via board committee composition, I am able to find significant ties between firm performance and how boards are structured. First, a positive rela...

  2. On the Limits of Nonprofit Firms

    OpenAIRE

    Echeverria, Manuel

    2013-01-01

    This thesis consists of two papers. The first gives a game-theoretical treatment of the institutional homogenization of value-oriented firms. It explains why intrinsically motivated, value-oriented firms like non-profits may become similar to for-profit firms in terms of organization and norms. It highlights and explains the pairs: value-oriented and flat organizations in contrast to value-neutral managers and hierarchical organizations. We consider a major donor like the government who deleg...

  3. Does Labor Diversity Affect Firm Productivity?

    OpenAIRE

    Parrotta, Pierpaolo; Pozzoli, Dario; Pytlikova, Mariola

    2010-01-01

    Using an employer-employee dataset, we analyze how diversity in cultural background, skills and demographic characteristics affects total factor productivity (TFP) of firms in Denmark. Implementing structural estimation of firms’ production function, we find evidence that labor diversity in skills/education significantly enhances firm performance as measured by firm TFP. Conversely, diversity in demographics and ethnicity brings mixed results – both dimensions of workforce diversity have eith...

  4. CEO Ability, Pay, and Firm Performance

    OpenAIRE

    Yuk Ying Chang; Sudipto Dasgupta; Gilles Hilary

    2010-01-01

    Do chief executive officers (CEOs) really matter? Do cross-sectional differences in firm performance and CEO pay reflect differences in CEO ability? Examining CEO departures over 1992-2002, we first find that the stock price reaction upon departure is negatively related to the firm's prior performance and to the CEO's prior pay. Second, the CEO's subsequent labor market success is greater if the firm's predeparture performance is better, the prior pay is higher, and the stock market's reactio...

  5. Entrepreneurship and the Economics of the Firm

    OpenAIRE

    Foss, Nicolai J.; Klein, Peter G.; Bylund, Per L.

    2011-01-01

    The study of entrepreneurship and the study of economic organizing lack contact. In fact, the modern theory of the firm virtually ignores entrepreneurship, while the literature on entrepreneurship often sees little value in the economic theory of the firm. In contrast, we argue in this chapter that entrepreneurship theory and the theory of the firm can be usefully integrated, and that doing so would improve both bodies of theory. Adding the entrepreneur to the theory of the fir...

  6. Effects of innovation types on firm performance

    OpenAIRE

    Günday, Gürhan; Gunday, Gurhan; Ulusoy, Gündüz; Ulusoy, Gunduz; Kılıç, Kemal; Kilic, Kemal; Lütfihak ALPKAN; Alpkan, Lutfihak

    2011-01-01

    Innovation is broadly seen as an essential component of competitiveness, embedded in the organizational structures, processes, products, and services within a firm. The objective of this paper is to explore the effects of the organizational, process, product, and marketing innovations on the different aspects of firm performance, including innovative, production, market, and financial performances, based on an empirical study covering 184 manufacturing firms in Turkey. A theoretical framework...

  7. Corruption and Firm Performance in Africa

    OpenAIRE

    Francis Teal; John McArthur

    2004-01-01

    This paper uses survey data to investigate empirically the importance of corruption in determining firm performance in Africa. We allow for the possibility of perception bias on the part of the respondents and for corruption being endogenous. We find that corruption is linked to significant adverse effects on firm performance in two ways. At the firm (or ^Slocal^T) level, companies that pay bribes have 20 percent lower levels of output per worker. At the economywide (or ^Sglobal^T) level, fir...

  8. Busyness and advising at Borsa Istanbul firms

    OpenAIRE

    Emrah Arioğlu; Pinar Arioğlu Kaya

    2015-01-01

    In this study, we investigate director busyness and advising for firms quoted at Borsa Istanbul. We show that firms prefer not to appoint directors with multiple directorships and superior advising skills to monitoring positions, potentially as a result of a trade-off between the monitoring and advising functions of directors. In addition, we find that busy boards have higher advising capacity compared to non-busy boards. Also, we show that firms that have busy boards or higher advising quali...

  9. Tax Compliance by Firms and Audit Policy

    OpenAIRE

    Ralph-C. Bayer; Frank Cowell

    2010-01-01

    Firms are usually better informed than tax authorities about market conditions and the potential profits of competitors. They may try to exploit this situation by underreporting their own taxable profits. The tax authority could offset firms' informational advantage by adopting "smarter" audit policies .that take into account the relationship between a firm's reported profits and reports for the industry as a whole. Such an audit policy will create an externality for the decision makers in th...

  10. Diversification, Organization, and Value of the Firm

    OpenAIRE

    USHIJIMA Tatsuo

    2015-01-01

    Because corporate diversification and organization co-evolve, diversification discounts, which are widely reported in the literature, can be caused by organizational structure, rather than by the industrial scope of the firm. The paper examines this possibility based on a large sample of Japanese firms for which the legal (parent-subsidiary) structure of the organization is easily observable. I identified a significant discount for diversified firms with and without control over the organizat...

  11. Negotiating access into firms: obstacles and strategies

    OpenAIRE

    Laryea, Sam; Hughes, Will

    2011-01-01

    Researchers often experience difficulties with the negotiation of access into firms for the purpose of data collection. The question we explore is: What are the main obstacles associated with access negotiation into firms; and what strategies do researchers employ to increase their chances of success? Our research work on the tendering process of contractors took place between 2006 and 2008. We successfully negotiated access into four firms (two each in Ghana and the UK) to observe live ex...

  12. Does Wage Dispersion Make All Firms Productive?

    OpenAIRE

    Mahy, Benoît; Rycx, Francois; Volral, Mélanie

    2011-01-01

    This article puts the relationship between wage dispersion and firm productivity to an updated test, taking advantage of access to detailed Belgian linked employer-employee panel data. Controlling for simultaneity issues, time-invariant workplace characteristics and dynamics in the adjustment process of productivity, empirical results reveal the existence of a positive impact from conditional intra-firm wage dispersion to firm productivity (measured by the average value added per hour worked)...

  13. Firms' age, process innovation and productivity growth

    OpenAIRE

    Huergo, Elena; Jaumandreu, Jordi

    2004-01-01

    This paper looks directly at the impact of firms' age and (process) innovations on productivity growth. A model that specifies productivity growth as an unknown function of these variables is devised and estimated using semiparametric methods. Results show that firms enter the market experiencing high productivity growth and that above-average growth rates tend to last for many years, but also that productivity growth of surviving firms converges. Process innovations at some point then lead t...

  14. Coevolution of Firm Capabilities and Industry Competition

    OpenAIRE

    Huygens, Marc; Baden-Fuller, Charles; Bosch, Frans; Volberda, Henk

    2001-01-01

    textabstractThis paper proposes that rival firms not only search for new capabilities within their organization, but also for those that rest in their competitive environment. An integrated analysis of these search processes at both firm and industry levels of analysis shows how their interaction makes industries and firms coevolve over time. To contribute to an enhanced understanding of the concept of coevolution, a dynamic and integrative framework crossing meso and micro levels of analysis...

  15. International working capital practices of Ghanaian firms

    Directory of Open Access Journals (Sweden)

    J. Abor

    2005-12-01

    Full Text Available International working capital management is important to firms frequently operating in the international market. This article investigates the international working capital practices of top Ghanaian firms involved in international trade. The objective of the study is to ascertain the extent to which Ghanaian firms use international working capital management vehicles. The article focuses on two main areas of international working capital management; international cash management and international sales and accounts receivables management. The results of this study reveal low level of use of international working capital vehicles among Ghanaian firms. Recommendations are made in this regard.

  16. Small firm subsistence and market dimensionality

    Science.gov (United States)

    Bruggeman, Jeroen; Péli, Gábor

    2014-04-01

    In many markets, large and small firms coexist. As large firms can in principle out-compete small ones, the actual presence of the latter asks for an explanation. In ours, we focus on the dimensionality of markets, which can change as a consequence of product innovations, preference elaboration or institutions. We show that increasing market dimensionality substantially enlarges the market periphery relative to the market center, which creates new potential niches for small firms. We thereby provide a parsimonious explanation for small firm subsistence.

  17. Tax Compliance and Firms' Strategic Interdependence

    OpenAIRE

    Bayer, R.; Cowell, Frank

    2006-01-01

    We focus on a relatively neglected area of the tax-compliance literature in economics, the behaviour of firms. We examine the impact of alternative audit rules on receipts from a tax on profits in the context of strategic inter- dependence of firms. In the market firms may compete in terms of either output or price. The enforcement policy can have an effect on firms behaviour in two dimensions - their market decisions as well as their compliance behaviour. An appropriate design of the enforce...

  18. Financial Structure and Diversification of European Firms

    OpenAIRE

    Lawless, Martina; O'Connell, Brian; O'Toole, Conor

    2014-01-01

    Small and medium enterprises have been shown to rely mainly on banks for funding and, unlike larger firms, rarely have direct access to capital markets. This paper looks at the extent to which SMEs avail of a wider range of funding options and how their use differs across firms and countries. Using the Survey of Access to Finance in Europe (SAFE) covering sixteen Euro Area countries, we find that firms are currently using two or three sources of finance to fund their firm's operations and hav...

  19. Equity market liberalization and firm growth

    OpenAIRE

    Thomas O'Connor

    2012-01-01

    Using a sample of 686 investable firms from 26 emerging market countries, I show that equity market liberalizations do not result in an increase in externally-financed growth rates for participating firms. In fact, I find to the contrary. The average firm appears to rely less and not more on external-financing once they become investable. These findings are in line with recent work which shows that firms issue less equity capital post-liberalization, and suggest that the gains from equity mar...

  20. Managing Firm Competitiveness in Global Markets

    OpenAIRE

    Gehlhar, M.; Regmi, A.; Stefanou, S.E.; Zoumas, B.

    2006-01-01

    The globalization profile of US food firms is mixed. US sales from foreign direct investment is now over six times the level of exports, while US processed food trade balance has moved from +$9 billion in 1995 to - $7 billion in 2004. Competitive forces drive firms to seek new areas of growth, with either portfolio expansion or penetration and expansion in new markets. Although the forces that weigh heavily on a firm are recognized, their influence in determining a firm¿s action in choosing a...