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Sample records for aplasia irreversible por

  1. Radiological Findings of Michel Aplasia

    Science.gov (United States)

    Umul, Ayse; Demirtas, Hakan; Celik, Ahmet Orhan

    2016-01-01

    Introduction: Congenital abnormalities of the inner ear is the most common cause of neurosensory hearing loss. Michel inner ear deformity is a rare developmental anomaly refers to the total aplasia of the inner ear. It is caused by developmental arrest of otic placode early during the third week of gestational age. Case report: We have discussed here that three year old girl diagnosed Michel aplasia with temporal bone computed tomography (CT) and temporal magnetic resonance imaging (MRI) findings. PMID:27482139

  2. Aplasia pura de serie roja post-trasplante alogeneico de células progenitoras hematopoyeticas ABO incompatible Pure red cell aplasia after ABO incompatible bone marrow transplantation

    OpenAIRE

    E. Bulliorsky; C. Shanley; G. Stemmelin; J. Ceresetto; O. Rabinovich

    2002-01-01

    El trasplante alogeneico de células progenitoras hematopoyéticas (TCPH) con incompatibilidad ABO entre el donante y el receptor puede en ocasiones asociarse a trastornos en la progenie eritroide desarrollada a partir de la médula ósea trasplantada, caracterizado por un funcionamiento tardío, inadecuado e incompleto de la misma. En este contexto, la aplasia pura de serie roja es la complicación más severa. Se han intentado tratamientos para la aplasia pura de serie roja post-TCPH con eritropoy...

  3. Aplasia of major pectoral muscle combined with renal aplasia and cystic malformation of common iliac vein

    DEFF Research Database (Denmark)

    Qvist, N; Nielsen, K; Christensen, P V

    1987-01-01

    We report a case of an eighteen-year-old male with combined aplasia of the major pectoral muscle, renal aplasia, and malformation of the common iliac vein. The possibility of a common genesis is discussed on the basis of embryology....

  4. Ectrodactyly with fibular aplasia : A separate entity?

    NARCIS (Netherlands)

    Menke, Leonie A.; Bijlsma, Emilia K.; van Essen, Anthonie J.; van den Boogaard, Marie-Jose H.; van Rijn, Rick R.; Cobben, Jan Maarten

    2008-01-01

    E/FA is the combination of ectrodactyly (split hand/foot malformation, SHFM) and fibular aplasia. It is a rare disorder considered to be inherited in an autosomal dominant fashion with reduced penetrance and variable expression. In order to determine recurrence risks for the two patients we describe

  5. Aplasia pura de serie roja post-trasplante alogeneico de células progenitoras hematopoyeticas ABO incompatible Pure red cell aplasia after ABO incompatible bone marrow transplantation

    Directory of Open Access Journals (Sweden)

    E. Bulliorsky

    2002-12-01

    Full Text Available El trasplante alogeneico de células progenitoras hematopoyéticas (TCPH con incompatibilidad ABO entre el donante y el receptor puede en ocasiones asociarse a trastornos en la progenie eritroide desarrollada a partir de la médula ósea trasplantada, caracterizado por un funcionamiento tardío, inadecuado e incompleto de la misma. En este contexto, la aplasia pura de serie roja es la complicación más severa. Se han intentado tratamientos para la aplasia pura de serie roja post-TCPH con eritropoyetina o plasmaféresis, con relativo éxito. Algunos autores han informado también la utilización de globulina antilinfocitaria, asumiendo que dicha aplasia selectiva de la serie roja en la médula ósea trasplantada es mediada por un mecanismo inmune. En este trabajo se describe un paciente portador de una leucemia aguda en quien se realizó un TCPH alogeneico (ABO incompatible con su donante. Teniendo niveles bajos de aglutininas contra el grupo sanguíneo de la donante, desarrolló una aplasia pura de serie roja post - TCPH. La misma no mejoró con tratamiento con eritropoyetina o con un refuerzo de progenitores hematopoyéticos de sangre periférica de la misma donante (boost, resolviéndose totalmente luego de un tratamiento exitoso con globulina antilinfocitaria de origen equino.ABO incompatibility in allogeneic bone marrow transplantation may be associated with incomplete or delayed erythroid engraftment, being pure red cell aplasia (PRCA the most severe complication in this setting. Attempts for the treatment of PRCA have been made with erythropoietin or with plasmapheresis with relative success, and some authors have reported the reversibility of PRCA with antilymphocyte globulin (ALG or ATG, based on the assumption that PRCA might be immunologically mediated. We report herewith a patient with acute leukemia who developed post - BMT pure red cell aplasia. His sibling donor (sister was HLA identical and ABO incompatible, having low agglutinin

  6. Microscopic irreversibility

    OpenAIRE

    Karl Gustafson

    2004-01-01

    First, I will recount the substance of several important conversations I had with Ilya Prigogine over the years. There is no doubt in my mind that Professor Prigogine firmly believed in the underlying stochasticity of the universe. Second, I will summarize my curiosity about the principle of detailed balance. In my opinion, so far it has always been put in by hand. Third, I will advance my own theory of microscopic irreversibility, that is, irreversibility at the quantum ...

  7. Aplasia pura de serie roja post-trasplante alogeneico de células progenitoras hematopoyeticas ABO incompatible

    OpenAIRE

    E. Bulliorsky; C. Shanley; G. Stemmelin; J. Ceresetto; O. Rabinovich

    2002-01-01

    El trasplante alogeneico de células progenitoras hematopoyéticas (TCPH) con incompatibilidad ABO entre el donante y el receptor puede en ocasiones asociarse a trastornos en la progenie eritroide desarrollada a partir de la médula ósea trasplantada, caracterizado por un funcionamiento tardío, inadecuado e incompleto de la misma. En este contexto, la aplasia pura de serie roja es la complicación más severa. Se han intentado tratamientos para la aplasia pura de serie roja post-TCPH con eritropoy...

  8. Aplasia pura de serie roja post-trasplante alogeneico de células progenitoras hematopoyeticas ABO incompatible

    Directory of Open Access Journals (Sweden)

    E. Bulliorsky

    2002-12-01

    Full Text Available El trasplante alogeneico de células progenitoras hematopoyéticas (TCPH con incompatibilidad ABO entre el donante y el receptor puede en ocasiones asociarse a trastornos en la progenie eritroide desarrollada a partir de la médula ósea trasplantada, caracterizado por un funcionamiento tardío, inadecuado e incompleto de la misma. En este contexto, la aplasia pura de serie roja es la complicación más severa. Se han intentado tratamientos para la aplasia pura de serie roja post-TCPH con eritropoyetina o plasmaféresis, con relativo éxito. Algunos autores han informado también la utilización de globulina antilinfocitaria, asumiendo que dicha aplasia selectiva de la serie roja en la médula ósea trasplantada es mediada por un mecanismo inmune. En este trabajo se describe un paciente portador de una leucemia aguda en quien se realizó un TCPH alogeneico (ABO incompatible con su donante. Teniendo niveles bajos de aglutininas contra el grupo sanguíneo de la donante, desarrolló una aplasia pura de serie roja post - TCPH. La misma no mejoró con tratamiento con eritropoyetina o con un refuerzo de progenitores hematopoyéticos de sangre periférica de la misma donante (boost, resolviéndose totalmente luego de un tratamiento exitoso con globulina antilinfocitaria de origen equino.

  9. Unilateral optic nerve aplasia associated with microphthalmos

    Directory of Open Access Journals (Sweden)

    Stanković-Babić Gordana

    2012-01-01

    Full Text Available Intraduction. Optic nerve aplasia is a rare developmental anomaly characterised by the congenital absence of the optic nerve, central retinal vessels and retinal ganglion cells that is seen most often in a unilaterally malformed eye. Case report. We reported a girl with a very rare anomaly of the eye, unilateral aplasia of the optic nerve and microphthalmia. We carried out a complete ophthalmological examination, A- and Bscan ultrasonography, magnetic resonance imaging (MRI of the orbit and brain, pediatrician, neurological examinations and karyotype determination. The examined child was a third child from the third regular pregnancy, born at term (39 GS, BM 3100 g. Family ocular history was negative. The right corneal diameter was 7.5 mm and left 10 mm. On dilated fundus examination, the right eye showed the absence of optic nerve and central retinal vessels. B-scan echography showed a small right globe (axial length 13.80 mm, normal size left globe (axial length 18.30 mm and the absence of optic nerve on the right eye. Physical and neurological findings and karyotype was normal. MRI of the orbits and brain marked asymmetry of globe size and unilateral absence of the optic nerve. The patient is under the control of a competent ophthalmologist and prosthetic. Conclusion. Further aesthetic and functional development of a young person is the primary goal in tracking this rare congenital optic nerve anomalies in the malformed eye.

  10. Pulmonary Aplasia in an Adult : A Case Report

    Directory of Open Access Journals (Sweden)

    Nurettin Yiyit

    2016-01-01

    Full Text Available Pulmonary aplasia is a rare congenital anomaly in which there are absence of pulmonary vessels, bronchus and parenchyma. It is distinguished from pulmonary agenesis by the presence of rudimentary stump bronchus. Patients are usually diagnosed in childhood. Patients without additional anomaly and the patients with mild disease can be diagnosed in adulthood. The left lung was not observed at the chest X-ray of 19-year-old male patient with respiratory distress in exercise. Left lung aplasia was diagnosed by computed tomography and ventilation perfusion scintigraphy. The patients with lung aplasia have an increased risk of infections. Therefore the follow-up of the patients is important.

  11. Genetics Home Reference: Müllerian aplasia and hyperandrogenism

    Science.gov (United States)

    Skip to main content Your Guide to Understanding Genetic Conditions Enable Javascript for addthis links to activate. ... Conditions Genes Chromosomes & mtDNA Resources Help Me Understand Genetics Home Health Conditions Müllerian aplasia and hyperandrogenism Müllerian ...

  12. Laparoscopic Morcellation of Didelphic Uterus With Cervical and Renal Aplasia

    OpenAIRE

    Altchek, Albert; Brodman, Michael; Schlosshauer, Peter; Deligdisch, Liane

    2009-01-01

    This is a case report (and review of the literature) of a 12-year and 10-month-old girl with a rare congenital anomaly of uterus didelphys, unilateral cervix aplasia, and ipsilateral renal aplasia. She had severe dysmenorrhea from the first menses. In an effort to preserve fertility, a cervical fistula was made that closed over. A laparoscopic hemi-hysterectomy was done successfully and rapidly with laparoscopic morcellation. Because no ureter was present, it was not necessary to trace it. Fo...

  13. Acquired pure megakaryocytic aplasia successfully treated with cyclosporine

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    Halima El Omri

    2010-12-01

    Full Text Available Acquired pure megakaryocytic aplasia is a rare hematological disorder characterized by thrombocytopenia with absent or markedly reduced megakaryocytes in the bone marrow. We report a case of a 25-year-old male diagnosed as acquired pure megakaryocytic aplasia. Treatment with prednisone and intravenous immunoglobulin failed, but he was successfully treated with cyclosporine, with complete remission after 90 days and normal platelet count maintained thereafter.

  14. From labyrinthine aplasia to otocyst deformity

    Energy Technology Data Exchange (ETDEWEB)

    Giesemann, Anja Maria; Goetz, Friedrich; Lanfermann, Heinrich [Hannover Medical School, Department of Diagnostic and Interventional Neuroradiology, Hannover (Germany); Neuburger, Juergen; Lenarz, Thomas [Hannover Medical School, Department of Otorhinolaryngology, Hannover (Germany)

    2010-02-15

    Inner ear malformations (IEMs) are rare and it is unusual to encounter the rarest of them, namely labyrinthine aplasia (LA) and otocyst deformity. They do, however, provide useful pointers as to the early embryonic development of the ear. LA is characterised as a complete absence of inner ear structures. While some common findings do emerge, a clear definition of the otocyst deformity does not exist. It is often confused with the common cavity first described by Edward Cock. Our purpose was to radiologically characterise LA and otocyst deformity. Retrospective analysis of CT and MRI data from four patients with LA or otocyst deformity. Middle and inner ear findings were categorised by two neuroradiologists. The bony carotid canal was found to be absent in all patients. Posterior located cystic structures were found in association with LA and otocyst deformity. In the most severe cases, only soft tissue was present at the medial border of the middle ear cavity. The individuals with otocyst deformity also had hypoplasia of the petrous apex bone. These cases demonstrate gradual changes in the two most severe IEMs. Clarification of terms was necessary and, based on these findings, we propose defining otocyst deformity as a cystic structure in place of the inner ear, with the cochlea, IAC and carotid canal absent. This condition needs to be differentiated from the common cavity described by Edward Cook. A clear definition of inner ear malformations is essential if outcomes following cochlear implantation are to be compared. (orig.)

  15. Acquired pure red cell aplasia in a child.

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    Sharma R

    2002-01-01

    Full Text Available Primary acquired pure red cell aplasia is a rare occurrence in childhood. An eleven-year old boy presented to us with pallor, which required multiple packed red cell transfusions. He did not have hepatosplenomegaly, jaundice or lymphadenopathy. Bone marrow examination revealed the diagnosis of pure red cell aplasia. All possible investigations were done to exclude secondary causes of pure red cell aplasia. No secondary cause was found on investigations. Rheumatoid factor and anti-nuclear antibodies were positive. He was started on oral steroids, to which he did not respond. He was then given cyclosporine A. Response to cyclosporine was dramatic and the child now does not require any transfusions.

  16. Aplasia and hypoplasia of the maxillary sinus: A case series

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    Nasim Jafari-Pozve

    2014-01-01

    Full Text Available Maxillary sinus aplasia and hypoplasia are rare conditions that can cause symptoms such as headaches and voice alteration. The majority of patients are asymptomatic, but these conditions must be noticed for importance of differential diagnosis such as infection and neoplasms. Conventional radiographs could not differentiate between inflammatory mucosal thickening, neoplasm, and hypoplasia of the sinus. Computed tomography (CT and also cone beam computed tomography (CBCT are the proper modalities to detect these conditions. In the present study, CBCT findings of three cases with maxillary sinus hypoplasia and aplasia are reported.

  17. Radial aplasia and chromosome 22q11 deletion.

    Science.gov (United States)

    Digilio, M C; Giannotti, A; Marino, B; Guadagni, A M; Orzalesi, M; Dallapiccola, B

    1997-01-01

    We report on a neonate with deletion 22q11 (del22q11) presenting with facial dysmorphism, ocular coloboma, congenital heart defect, urogenital malformations, and unilateral radial aplasia. This malformation complex includes features frequently occurring in velocardiofacial syndrome as well as findings described in the CHARGE and VACTERL associations. To our knowledge, the present case is the first report of radial aplasia in del22q11. This observation further supports and extends the clinical variability of del22q11. Images PMID:9391893

  18. Primary cutaneous aspergillosis and idiopathic bone marrow aplasia*

    Science.gov (United States)

    Furlan, Karina Colossi; Pires, Mario Cezar; Kakizaki, Priscila; Chartuni, Juliana Cabral Nunes; Valente, Neusa Yuriko Sakai

    2016-01-01

    We describe the case of a 9-year-old boy with idiopathic bone marrow aplasia and severe neutropenia, who developed skin ulcers under cardiac monitoring electrodes. The diagnosis of primary cutaneous aspergillosis was made after the second biopsy and culture. Imaging investigation did not reveal internal fungal infection. The child was treated, but did not improve and died 3 months after admission. The report highlights and discusses the preventable risk of aspergillus skin infection in immunocompromised patients. PMID:27438213

  19. Irreversible processes kinetic theory

    CERN Document Server

    Brush, Stephen G

    2013-01-01

    Kinetic Theory, Volume 2: Irreversible Processes deals with the kinetic theory of gases and the irreversible processes they undergo. It includes the two papers by James Clerk Maxwell and Ludwig Boltzmann in which the basic equations for transport processes in gases are formulated, together with the first derivation of Boltzmann's ""H-theorem"" and a discussion of this theorem, along with the problem of irreversibility.Comprised of 10 chapters, this volume begins with an introduction to the fundamental nature of heat and of gases, along with Boltzmann's work on the kinetic theory of gases and s

  20. The association of aplasia cutis congenita with therapy of maternal thyroid disease.

    Science.gov (United States)

    Kalb, R E; Grossman, M E

    1986-09-01

    Aplasia cutis congenita, the localized absence of skin at birth, usually is an isolated scalp defect. We examined an infant with aplasia cutis congenita associated with maternal Grave's disease and the use of methimazole during pregnancy. This association was reported twice before. It has certain implications with respect to therapy of pregnant hyperthyroid women. PMID:3774652

  1. Irreversibility, Uncertainty, and Investment

    OpenAIRE

    Robert S. Pindyck

    1990-01-01

    Most investment expenditures have two important characteristics: First, they are largely irreversible; the firm cannot disinvest, so the expenditures are sunk costs. Second, they can be delayed, allowing the firm to wait for new information about prices, costs, and other market conditions before committing resources. An emerging literature has shown that this has important implications for investment decisions, and for the determinants of investment spending. Irreversible investment is especi...

  2. Electroconvulsive Therapy and Corpus Callosum Aplasia: A 3-Year Followup

    Directory of Open Access Journals (Sweden)

    Ulrich Palm

    2011-01-01

    Full Text Available Electroconvulsive Therapy (ECT is a powerful treatment option in severe or chronic catatonic states and has been reported to be useful in oligophrenic patients. We report the followup medical history of a patient with corpus callosum aplasia (or agenesis who was continuously treated with ECT over three years. First, he improved considerably after a series of ECT, but relapses of catatonia made a continuous, weekly ECT necessary. Due to the severity of the brain malformation, an add-on medication with benzodiazepines and second generation antipsychotics was necessary to treat catatonic symptoms. This case emphasises the benefits of long-term ECT in oligophrenic patients.

  3. THE PURE RED BLOOD CELL APLASIA IN RENAL TRANSPLANT RECIPIENT

    Directory of Open Access Journals (Sweden)

    B. T. Dzumabaeva

    2011-01-01

    Full Text Available The pure red blood cell aplasia of renal transplant recipients caused by parvovirus B19 (PB19 is characterized by persistent anemia which resistant to erythropoietin therapy, lack of reticulocytes, bone marrow hypoplasia, and clinically accompanied by severe recurrent bacterial, fungal and viral infection. In case of reactivation PB19 it is necessarv, first of all, eliminate the causes activation of this virus and to cancel or reduce the dose of drugs which depressed the normal hematopoiesis germs, thus to reduce the pancytopenia associating complications in this population. 

  4. Pure red cell aplasia induced by epoetin zeta.

    Science.gov (United States)

    Panichi, Vincenzo; Ricchiuti, Guido; Scatena, Alessia; Del Vecchio, Lucia; Locatelli, Francesco

    2016-08-01

    Pure red cell aplasia (PRCA) may develop in patients with chronic kidney disease receiving erythropoiesis-stimulating agents (ESA). We report on a 72-year-old patient who developed hypo-proliferative anaemia unresponsive to ESA following the administration of epoetin zeta subcutaneously for 7 months. On the basis of severe isolated hypoplasia of the erythroid line in the bone marrow and high-titre neutralizing anti-erythropoietin antibodies (Ab), a diagnosis of Ab-mediated PRCA was made. Epoetin zeta was discontinued and the patient was given steroids. This was associated with anaemia recovery. To our knowledge this is the first PRCA case related to epoetin zeta. PMID:27478604

  5. Pure red cell aplasia following autoimmune hemolytic anemia: An enigma

    Directory of Open Access Journals (Sweden)

    M Saha

    2013-01-01

    Full Text Available A 26-year-old previously healthy female presented with a 6-month history of anemia. The laboratory findings revealed hemolytic anemia and direct antiglobulin test was positive. With a diagnosis of autoimmune hemolytic anemia (AIHA, prednisolone was started but was ineffective after 1 month of therapy. A bone marrow trephine biopsy revealed pure red cell aplasia (PRCA showing severe erythroid hypoplasia. The case was considered PRCA following AIHA. This combination without clear underlying disease is rare. Human parvovirus B19 infection was not detected in the marrow aspirate during reticulocytopenia. The patient received azathioprine, and PRCA improved but significant hemolysis was once again documented with a high reticulocyte count. The short time interval between AIHA and PRCA phase suggested an increased possibility of the evolution of a single disease.

  6. Pure red cell aplasia in a simultaneous pancreas-kidney transplantation patient: inside the erythroblast

    Directory of Open Access Journals (Sweden)

    Francesca Labbadia

    2012-09-01

    Full Text Available A case of pure red cell aplasia in a simultaneous kidney-pancreas transplant recipient on immunosuppressive therapy is reported here. The patient presented with anemia unresponsive to erythropoietin treatment. Bone marrow cytomorphology was highly suggestive of parvovirus pure red cell aplasia, which was confirmed with serology and polymerase chain reaction positive for parvovirus B19 DNA in peripheral blood. After the administration of intravenous immunoglobulin the anemia improved with a rising number of the reticulocytes.

  7. Uterine horn aplasia with complications in two mixed-breed bitches : case report

    OpenAIRE

    M.L. Schulman; L.A. Bolton

    1997-01-01

    Unilateral segmental uterine horn aplasia was found in 2 mixed-breed bitches. The 1st bitch was presented with clinical signs of acute abdominal pain, and pyometra was suspected. Pyometra was confirmed surgically with rupture of a blind-ending cranial portion of the anomalous right uterine horn, which had resulted in peritonitis. The 2nd bitch was presented for routine ovariohysterectomy. The right uterine horn was affected by segmental aplasia, with mucometra of the cranial portion of the af...

  8. Irreversible quantum baker map.

    Science.gov (United States)

    Łoziński, Artur; Pakoński, Prot; Zyczkowski, Karol

    2002-12-01

    We propose a generalization of the model of classical baker map on the torus, in which the images of two parts of the phase space do overlap. This transformation is irreversible and cannot be quantized by means of a unitary Floquet operator. A corresponding quantum system is constructed as a completely positive map acting in the space of density matrices. We investigate spectral properties of this superoperator and their link with the increase of the entropy of initially pure states.

  9. Irreversible Quantum Baker Map

    CERN Document Server

    Lozinski, A; Zyczkowski, K; Lozinski, Artur; Pakonski, Prot; Zyczkowski, Karol

    2002-01-01

    We propose a generalization of the model of classical baker map on the torus, in which the images of two parts of the phase space do overlap. This transformation is irreversible and cannot be quantized by means of a unitary Floquet operator. A corresponding quantum system is constructed as a completely positive map acting in the space of density matrices. We investigate spectral properties of this super-operator and their link with the increase of the entropy of initially pure states.

  10. Marrow fat cell: response to x-ray induced aplasia

    International Nuclear Information System (INIS)

    Adipose tissue is an integral structural component of normal rabbit marrow and is believed to behave primarily as a cushion in response to hemopoietic proliferation, accommodating to changes in hemopoiesis by change in either size or number or both of the fat cells in order to maintain constancy of the marrow volume. To test this hypothesis, aplasia of the right femur of New Zealand white rabbits was induced by x irradiation with 8000 rads; the left unirradiated limb served as control. Twenty-four hours before sacrifice 50 μCi of palmitate-114C was administered intravenously and the marrow of both femurs removed. Samples of perinephric fat were taken for comparison. Fat cell volume, C14 palmitate turnover and fatty acid composition were determined. The total number of fat cells in the entire marrow of both femurs was calculated. The measurements showed no difference in size or fatty acid turnover of the fat cells in the irradiated aplastic marrow from the cells of the control marrow. The number of fat cells in both the irradiated and the unirradiated control femurs was essentially the same. These findings do not support the view that marrow fat cells respond to diminished hematopoiesis by either increase in their volume or number. In addition, the findings suggest that both marrow and subcutaneous fat cells are fairly resistant to high doses of x-ray irradiation

  11. Nonequilibrium and irreversibility

    CERN Document Server

    Gallavotti, Giovanni

    2014-01-01

    This book concentrates on the properties of the stationary states in chaotic systems of particles or fluids, leaving aside the theory of the way they can be reached. The stationary states of particles or of fluids (understood as probability distributions on microscopic configurations or on the fields describing continua) have received important new ideas and data from numerical simulations and reviews are needed. The starting point is to find out which time invariant distributions come into play in physics. A special feature of this book is the historical approach. To identify the problems the author analyzes the papers of the founding fathers Boltzmann, Clausius and Maxwell including translations of the relevant (parts of ) historical documents. He also establishes a close link between treatment of irreversible phenomena in statistical mechanics and the theory of chaotic systems at and beyond the onset of turbulence as developed by Sinai, Ruelle, Bowen (SRB) and others: the author gives arguments intending t...

  12. Irreversible Simulated Tempering

    Science.gov (United States)

    Sakai, Yuji; Hukushima, Koji

    2016-10-01

    An extended ensemble Monte Carlo algorithm is proposed by introducing a violation of the detailed balance condition to the update scheme of the inverse temperature in simulated tempering. Our method, irreversible simulated tempering, is constructed on the basis of the framework of the skew detailed balance condition. By applying this method to the ferromagnetic Ising model in two dimensions on a square lattice as a benchmark, the dynamical behavior of the inverse temperature and an autocorrelation function of the magnetization are studied numerically. It is found that the relaxation dynamics of the inverse temperature qualitatively change from diffusive to ballistic on violating the detailed balance condition. Consequently, the autocorrelation time of the magnetization is several times smaller than that for the conventional algorithm satisfying the detailed balance condition.

  13. Aplasia transitória da série vermelha na anemia falciforme Transient red cell aplasia in sickle cell disease

    Directory of Open Access Journals (Sweden)

    Mônica P. A. Veríssimo

    2007-09-01

    Full Text Available A doença falciforme, devido à vida média encurtada das hemácias, pelo quadro de hemólise crônica, pode apresentar um quadro clínico grave de anemia quando ocorre supressão da eritropoese devida à infecção pelo Parvovírus humano B19. O quadro clínico apresenta-se com febre, que pode preceder a anemia grave, fraqueza e mal- estar, além de sinais laboratoriais como queda da hemoglobina e reticulocitopenia importante. Diagnóstico laboratorial pode ser por imunofluorescência ou ensaio enzimático. O tratamento é a transfusão de concentrado de hemácias. Pode haver complicações associadas a esta infecção, tais como seqüestro esplênico, seqüestro hepático, síndrome torácica aguda, síndrome nefrótica, meningoencefalite e acidente vascular cerebral. Estratégias de prevenção poderão mudar a morbi-mortalidade desta condição no paciente portador de doença falciforme.Sickle cell disease due to shortened life span of red blood cells by hemolysis, may present with severe anemia when erythropoietic suppression occurs due to infection by the Human parvovirus B19. The clinical presentation presents with fever, which may precede transient red cell aplasia, as well as laboratorial signs such as a drop in hemoglobin and significant reticulo cytopenia. Laboratorial diagnosis may be by immunofluorescence or enzymatic assays. Treatment is achieved by transfusion of packed red blood cells. Complications may be associated to this infection, including splenic and hepatic sequestration, acute chest syndrome, nephrotic syndrome, meningoencephalitis and strokes. Strategies of prevention are able to change the morbidity and mortality of this condition in sickle cell disease patients.

  14. A Patient with Unilateral Tibial Aplasia and Accessory Scrotum: A Pure Coincidence or Nonfortuitous Association?

    Directory of Open Access Journals (Sweden)

    Zoran Gucev

    2010-01-01

    Full Text Available Tibial aplasia is an uncommon lower limb malformation that can occur isolated or be part of a more complex malformation pattern. We describe a 9-year-old boy born after uneventful pregnancy and delivery. Family history was negative for maternal diabetes and other malformations. The patient presented with left tibial aplasia and homolateral prexial foot polydactyly. He also displayed enamel dysplasia and bifid scotum with cryptorchidism. Literature review failed to identify a significant syndromic association between lower limb defects of the tibial type and the genital anomalies reported here. The combination of tibial aplasia with midline genital malformations further supports the hypothesis that the tibial ray development mirrors the morphogenetic process of the radial structures. Accordingly, the malformation pattern observed in the present patient may be pathogenetically explained by an insult occurring during late blastogenesis.

  15. Uterine horn aplasia with complications in two mixed-breed bitches : case report

    Directory of Open Access Journals (Sweden)

    M.L. Schulman

    1997-07-01

    Full Text Available Unilateral segmental uterine horn aplasia was found in 2 mixed-breed bitches. The 1st bitch was presented with clinical signs of acute abdominal pain, and pyometra was suspected. Pyometra was confirmed surgically with rupture of a blind-ending cranial portion of the anomalous right uterine horn, which had resulted in peritonitis. The 2nd bitch was presented for routine ovariohysterectomy. The right uterine horn was affected by segmental aplasia, with mucometra of the cranial portion of the affected horn. Histopathology demonstrated both uteri to have diffuse cystic endometrial hyperplasia. It is postulated that cystic endometrial hyperplasia, together with the congenital anomaly, resulted in pyometra in one case and in mucometra in the other case. This is believed to be the 1st report of uterine horn aplasia in the bitch in association with clinical signs and lesions other than infertility.

  16. Congenital aplasia of the optic chiasm and esophageal atresia: a case report

    Directory of Open Access Journals (Sweden)

    Madonia Maurizio

    2011-08-01

    Full Text Available Abstract Introduction The complete absence of the chiasm (chiasmal aplasia is a rare clinical condition. Hypoplasia of the optic nerve and congenital nystagmus are almost invariably associated characteristics. Microphthalmos or anophthalmos are common features in chiasmal aplasia, while central nervous system abnormalities are less frequent. Esophageal atresia can be isolated or syndromic. In syndromic cases, it is frequently associated with cardiac, limb, renal or vertebral malformations and anal atresia. More rarely, esophageal atresia can be part of anophthalmia-esophageal-genital syndrome, which comprises anophthalmia or microphthalmia, genital abnormalities, vertebral defects and cerebral malformations. Here, a previously unreported case of chiasmal aplasia presenting without microphthalmos and associated with esophageal atresia is described. Case presentation Aplasia of the optic chiasm was identified in a Caucasian Italian 8-month-old boy with esophageal atresia. An ultrasound examination carried out at 21 weeks' gestation revealed polyhydramnios. Intrauterine growth retardation, esophageal atresia and a small atrial-septal defect were subsequently detected at 28 weeks' gestation. Repair of the esophageal atresia was carried out shortly after birth. A jejunostomy was carried out at four months to facilitate enteral feeding. The child was subsequently noted to be visually inattentive and to be neurodevelopmentally delayed. Magnetic resonance imaging revealed chiasmal aplasia. No other midline brain defects were found. His karyotype was normal. Conclusion If achiasmia is a spectrum, our patient seems to depict the most severe form, since he appears to have an extremely severe visual impairment. This is in contrast to most of the cases described in the literature, where patients maintain good--or at least useful-- visual function. To the best of our knowledge, the association of optic nerve hypoplasia, complete chiasmal aplasia, esophageal

  17. RETREATMENT WITH FLUDARABINE AND CYCLOSPORINE FOR ONE CASE OF REFRACTORY PURE RED CELL APLASIA

    Institute of Scientific and Technical Information of China (English)

    Guang-sheng He; Xiang Zhang; De-pei Wu; Ai-ning Sun; Miao Miao; Xiu-li Wang; Zheng-ming Jin

    2008-01-01

    @@ MANY cases of pure red cell aplasia (PRCA) were mediated by over-function of immune cells, and responded well to immunosuppres-sive therapy.1 Sometimes refractory cases also arose. Fludara-bine is an analogue of adenosine resistant to deamination which is widely used for B-chronic lymphocytic leukemia (CLL) and other hematological malignancies.

  18. Reconstruction of bilateral tibial aplasia and split hand-foot syndrome in a father and daughter

    Directory of Open Access Journals (Sweden)

    Ali Al Kaissi

    2014-01-01

    Full Text Available Background: Tibial aplasia is of heterogeneous aetiology, the majority of reports are sporadic. We describe the reconstruction procedures in two subjects - a daughter and father manifested autosomal dominant (AD inheritance of the bilateral tibial aplasia and split hand-foot syndrome. Materials and Methods: Reconstruction of these patients required multiple surgical procedures and orthoprosthesis was mandatory. The main goal of treatment was to achieve walking. Stabilization of the ankle joint by fibular-talar-chondrodesis on both sides, followed by bilateral Brown-procedure at the knee joint level has been applied accordingly. Results: The outcome was with improved function of the deformed limbs and walking was achieved with simultaneous designation of orthotic fitting. Conclusion: This is the first study encompassing the diagnosis and management of a father and daughter with bilateral tibial aplasia associated with variable split hand/foot deformity without foot ablation. Our patients showed the typical AD pattern of inheritance of split-hand/foot and tibial aplasia.

  19. APLASIA CUTIS CONGENITAL WITH AMNIOTIC BAND DISRUPTION COMPLEX: A RARE CASE REPORT

    Directory of Open Access Journals (Sweden)

    Pradipprava

    2015-09-01

    Full Text Available Aplasia cutis congenita (ACC is congenital absence of skin, most commonly affecting scalp. Etiology is multifactorial like intrauterine infection, teratogens, vascular causes, genetic syndromes etc. We here represent an infant with ACC involving extremities and associated with amniotic band disruption complex. He was treated conservatively and discharged.

  20. Tumor Ablation with Irreversible Electroporation

    OpenAIRE

    Al-Sakere, Bassim; André, Franck,; Bernat, Claire; Connault, Elisabeth; Opolon, Paule; Davalos, Rafael V.; Rubinsky, Boris; Mir, Lluis M.

    2007-01-01

    We report the first successful use of irreversible electroporation for the minimally invasive treatment of aggressive cutaneous tumors implanted in mice. Irreversible electroporation is a newly developed non-thermal tissue ablation technique in which certain short duration electrical fields are used to permanently permeabilize the cell membrane, presumably through the formation of nanoscale defects in the cell membrane. Mathematical models of the electrical and thermal fields that develop dur...

  1. Segmental aplasia of the uterine horn with ipsilateral renal agenesis in a cat.

    Science.gov (United States)

    Chang, Jinhwa; Jung, Joo-hyun; Yoon, Junghee; Choi, Min-cheol; Park, Jae Hak; Seo, Kang-Moon; Jeong, Seong Mok

    2008-06-01

    A nine-month-old domestic short haired cat was admitted with the history of acute vomiting, depression and shivering. Abdominal ultrasonography revealed minimum enlargement of the right uterine horn filled with anechoic fluid. On excretory urography, functionally and anatomically normal, enlarged left kidney was found, but right kidney was absent. It was preliminary diagnosed as hydrometra with right renal agenesis. Aiming at the correction of hydrometra, we performed ovariohysterectomy. During spaying, we found a missing segment of distal part of the right uterine horn and absence of ipsilateral kidney and ureter. Compressed uterine structure and segmental aplasia of right uterine horn were found in histopathological investigation. Taken together, it was diagnosed as a segmental aplasia of uterine horn with ipsilateral renal agenesis. PMID:18628611

  2. Pulmonary Sequestration with Renal Aplasia and Elevated SUV Level in PET/CT

    Directory of Open Access Journals (Sweden)

    Serdar Şen

    2012-01-01

    Full Text Available Extralobar sequestration with other bronchopulmonary malformations is commonly seen; however, the association of extralobar sequestration with renal aplasia is very rare. A 75-year-old female patient was admitted with back pain. Ultrasonography revealed aplasia of the left kidney and tomography showed 6×4.5 cm sized tumor in the left hemithorax at the posterobasal area. The lesion has focally increased glycolytic activity (SUVmax: 3.2 at the left upper pole on positron emission tomography scan (PET/CT. Sequestrectomy was performed after the confirmation by frozen section that the lesion was benign and of extrapulmonary sequestration. No complication occurred during postoperative and 50-month follow-up period.

  3. [Acute hepatitis-associated pure red cell aplasia: a case report].

    Science.gov (United States)

    Della Loggia, Paolo; Cremonini, Laura

    2002-12-01

    After a holiday in Egypt, a 57-year-old caucasian woman developed acute hepatitis A. The illness seemed initially to have a benign course, with a decreasing trend of hepatic enzymes and an apparent recovery. Three weeks later a relapse occurred. Recurrence of symptoms and aminotransferase elevation were associated with severe anemia; a hyporegenerative anemia was diagnosed and all laboratory findings were consistent with pure red cell aplasia. The haematologic disorder was successfully treated with red cell transfusion and glucocorticoids.

  4. Anti-Erythropoietin Antibody Associated Pure Red Cell Aplasia Resolved after Liver Transplantation

    OpenAIRE

    Hung, Annie K.; Jennifer Guy; Behler, Caroline M.; Lee, Eugene E.

    2015-01-01

    Patients undergoing antiviral therapy for chronic hepatitis C often develop anemia secondary to ribavirin and interferon. Recombinant erythropoietin has been used to improve anemia associated with antiviral therapy and to minimize dose reductions, which are associated with decreased rates of sustained virologic response. A rare potential side effect of recombinant erythropoietin is anti-erythropoietin antibody associated pure red cell aplasia. In chronic kidney disease patients with this enti...

  5. Tumor ablation with irreversible electroporation.

    Directory of Open Access Journals (Sweden)

    Bassim Al-Sakere

    Full Text Available We report the first successful use of irreversible electroporation for the minimally invasive treatment of aggressive cutaneous tumors implanted in mice. Irreversible electroporation is a newly developed non-thermal tissue ablation technique in which certain short duration electrical fields are used to permanently permeabilize the cell membrane, presumably through the formation of nanoscale defects in the cell membrane. Mathematical models of the electrical and thermal fields that develop during the application of the pulses were used to design an efficient treatment protocol with minimal heating of the tissue. Tumor regression was confirmed by histological studies which also revealed that it occurred as a direct result of irreversible cell membrane permeabilization. Parametric studies show that the successful outcome of the procedure is related to the applied electric field strength, the total pulse duration as well as the temporal mode of delivery of the pulses. Our best results were obtained using plate electrodes to deliver across the tumor 80 pulses of 100 micros at 0.3 Hz with an electrical field magnitude of 2500 V/cm. These conditions induced complete regression in 12 out of 13 treated tumors, (92%, in the absence of tissue heating. Irreversible electroporation is thus a new effective modality for non-thermal tumor ablation.

  6. [Risk factors for teeth aplasia and hypoplasia in cleft lip and palate children].

    Science.gov (United States)

    Korolenkova, M V; Starikova, N V; Ageeva, L V

    2016-01-01

    The aim of the study was to assess the significance of environmental risk factors for teeth aplasia and hypoplasia in cleft lip and palate children. Two hundred and forty-seven cleft lip and palate (CLP) children were enrolled in the study including 105 (42.5%) with bilateral CLP and 57.5% with unilateral CLP. The mean age was 11.2±4.9 years. Teeth condition was assessed clinically and radiologically. The impact of risk factors for teeth anomalies was analyzed by retrospective data obtained from computer database (absence of preoperative orthopedic treatment, palatal defects after primary palatoplasty and type of primary procedures). Surgical trauma by early periosteoplasty (at the age of 3-4 months), excessive scarring and tissue traction due to absence of early orthopedic treatment and palatal defect were associated with significantly higher incidence of incisors hypoplasia (both developmental enamel defects and microdentia) and aplasia of central incisors not seen in the other study subgroups. Incisors aplasia and hypoplasia in CLP patients do not always have disembryogenic origin but may depend on external environmental factors, including surgical trauma.

  7. Irreversible Electroporation of Hepatic Malignancy

    OpenAIRE

    Narayanan, Govindarajan; Froud, Tatiana; Suthar, Rekhaben; Barbery, Katuska

    2013-01-01

    Hepatocellular carcinoma (HCC) is a worldwide problem of epidemic proportions, best treated in a multidisciplinary setting. Major advances have been made in all specialties that manage patients with HCC, with surgical options at one end of the spectrum and palliative chemotherapy on the other, and the vast majority of patients require the involvement and expertise of interventional oncology. Several ablative and transarterial technologies are currently available. Irreversible electroporation ...

  8. Ideally Efficient Irreversible Molecular Gears

    OpenAIRE

    Sokolov, I. M.

    2000-01-01

    Typical man-made locomotive devices use reversible gears, as cranks, for transforming reciprocating motion into directed one. Such gears are holonomic and have the transduction efficiency of unity. On the other hand, a typical gear of molecular motors is a ratchet rectifier, which is irreversible. We discuss what properties of rectifier mostly influence the transduction efficiency and show that an apliance which locks under backwards force can achieve the energetic efficiency of unity, withou...

  9. Irreversible Does Not Mean Unavoidable

    OpenAIRE

    Matthews, H.D.; Solomon, Susan

    2013-01-01

    Understanding how decreases in CO[subscript 2] emissions would affect global temperatures has been hampered in recent years by confusion regarding issues of committed warming and irreversibility. The notion that there will be additional future warming or “warming in the pipeline” if the atmospheric concentrations of carbon dioxide were to remain fixed at current levels (1) has been misinterpreted to mean that the rate of increase in Earth's global temperature is inevitable, regardless of how ...

  10. Ecological optimization for generalized irreversible Carnot refrigerators

    International Nuclear Information System (INIS)

    The optimal ecological performance of a Newton's law generalized irreversible Carnot refrigerator with the losses of heat resistance, heat leakage and internal irreversibility is derived by taking an ecological optimization criterion as the objective, which consists of maximizing a function representing the best compromise between the exergy output rate and exergy loss rate (entropy production rate) of the refrigerator. Numerical examples are given to show the effects of heat leakage and internal irreversibility on the optimal performance of generalized irreversible refrigerators

  11. Information symmetries in irreversible processes

    Science.gov (United States)

    Ellison, Christopher J.; Mahoney, John R.; James, Ryan G.; Crutchfield, James P.; Reichardt, Jörg

    2011-09-01

    We study dynamical reversibility in stationary stochastic processes from an information-theoretic perspective. Extending earlier work on the reversibility of Markov chains, we focus on finitary processes with arbitrarily long conditional correlations. In particular, we examine stationary processes represented or generated by edge-emitting, finite-state hidden Markov models. Surprisingly, we find pervasive temporal asymmetries in the statistics of such stationary processes. As a consequence, the computational resources necessary to generate a process in the forward and reverse temporal directions are generally not the same. In fact, an exhaustive survey indicates that most stationary processes are irreversible. We study the ensuing relations between model topology in different representations, the process's statistical properties, and its reversibility in detail. A process's temporal asymmetry is efficiently captured using two canonical unifilar representations of the generating model, the forward-time and reverse-time ɛ-machines. We analyze example irreversible processes whose ɛ-machine representations change size under time reversal, including one which has a finite number of recurrent causal states in one direction, but an infinite number in the opposite. From the forward-time and reverse-time ɛ-machines, we are able to construct a symmetrized, but nonunifilar, generator of a process—the bidirectional machine. Using the bidirectional machine, we show how to directly calculate a process's fundamental information properties, many of which are otherwise only poorly approximated via process samples. The tools we introduce and the insights we offer provide a better understanding of the many facets of reversibility and irreversibility in stochastic processes.

  12. Quantum mechanical irreversibility and measurement

    CERN Document Server

    Grigolini, P

    1993-01-01

    This book is intended as a tutorial approach to some of the techniques used to deal with quantum dissipation and irreversibility, with special focus on their applications to the theory of measurements. The main purpose is to provide readers without a deep expertise in quantum statistical mechanics with the basic tools to develop a critical judgement on whether the major achievements in this field have to be considered a satisfactory solution of quantum paradox, or rather this ambitious achievement has to be postponed to when a new physics, more general than quantum and classical physics, will

  13. A case of severe congenital kyphoscoliosis secondary to multiple bilateral thoracic pedicle aplasia

    Energy Technology Data Exchange (ETDEWEB)

    Geoffray, Anne; Leloutre, Beatrice; Albertario, Marco; Bechard-Sevette, Nancy [Fondation Lenval Children' s Hospital, Department of Pediatric Imaging, Nice (France); Clement, Jean-Luc [Fondation Lenval Children' s Hospital, Department of Orthopedic and Spine Surgery, Nice (France)

    2008-07-15

    A 9-month-old boy with congenital kyphoscoliosis secondary to multiple bilateral thoracic pedicle aplasias is presented. This anomaly has rarely been described in the literature. Plain films showed absence of thoracic pedicles bilaterally from T2 to T9, which was better demonstrated on CT multiplanar and 3-D reformatted images. There were no neurological symptoms even though the deformity progressed rapidly. Congenital kyphosis or kyphoscoliosis is often related to spinal anomalies that are located on the anterior aspect of the vertebrae. However, posterior anomalies may also be responsible and should be recognized before neurological complications occur. (orig.)

  14. Prenatal ultrasonography of trisomy 18 with radial aplasia: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jee Young; Lee, Yeon Hee [Dankook University College of Medicine, Seoul (Korea, Republic of)

    2002-06-15

    Trisomy 18 (Edward syndrome) is the second most common chromosomal anomaly of the autosomal trisomy. Prenatal diagnosis of trisomy 18 is extremely important because of the complex malformations and lethal prognosis. Prenatal sonographic findings at 17 weeks of gestation showing radial aplasia with upper limb contracture, omphalocele, and suspicious esophageal atresia suggested the diagnosis and led to amniocentesis. Karyotyping revealed trisomy 18 (47 XX, +18, and characteristic autopsy findings were identified. We report a case of prenatally diagnosed trisomy 18 with a review of literatures.

  15. [Aplasia and hypoplasia of the side of the nose in the Mocha Period and today].

    Science.gov (United States)

    Pirsig, W

    1989-01-01

    In earthenware vessels from the Moche period (200-700 A.D.) pathological findings of nasal deformities have been depicted in a realistic manner. By means of two recent casuistics and of two portrait vessels of Old Peru it is demonstrated how exactly the nasal pathology was observed by the artists of the Moche period. The first example shows a unilateral hypoplasia of the nasal ala due to injury in early childhood, the second example shows a bilateral aplasia of the nasal alae due to an intrauterine growth disturbance. PMID:2690796

  16. [Bilateral deep venous thrombosis and vena cava aplasia treated with local thrombolysis

    DEFF Research Database (Denmark)

    Pelta, A.M.; Jørgensen, Maja; Just, Sven Richardt Lundgren;

    2008-01-01

    In this case report the treatment of a young man with bilateral iliaco-femoral DVT and vena cava aplasia is presented. The patient was treated with catheter-directed thrombolysis; the catheters were introduced in the thrombus of both legs via v. popliteae. The treatment led to almost complete thr...... thrombus resolution and no valvular incompetence at three months follow-up. In our opinion this treatment should be offered even in complex cases of acute proximal deep venous thrombosis Udgivelsesdato: 2008/5/19...

  17. [Aplasia and hypoplasia of the optic nerve. Comparison of 2 cases].

    Science.gov (United States)

    Pisaturo, C; Dolci, A; Pessagno, A; Padua, G L; Dassio, D A; De Negri, M

    1996-10-01

    Hypoplasia and aplasia of the optic nerve are congenital anomalies characterized respectively by a marked volume reduction (very small papilla, often identifiable only as a rosy-yellowish area from which the retinal vessels emerge) and by the absence of the optic disk (absence of the nerve and mainly of its vessels) and of the visual functions. These anomalies are often associated with malformations of the central nervous system and of the ocular structures. The defects originate in the embryonal period due to the arrested development of the mesodermal component towards the head of the optic nerve. The aim of this study is to try to interpret the different clinical manifestations of the disease by observing two cases (a female and a male) with a clinical picture of aplasia and hypoplasia of the optic nerve respectively. Both cases presented the following clinical characteristics: developmental defects of the optic nerve, severe microcephaly, positive IgG antibodies against CMV. The association of the optic nerve defect with microcephaly is due to the embryogenic origin of the optic vescicle by prosencephalon. The resulting clinical picture is probably the outcome of an interfering process that the authors have presumed in CMV intrauterine infection, after having excluded the most frequent teratogenic agents (maternal diabetes, tabagism, intake of alcohol ad drugs). Moreover, the different degree of ocular involvement and the different time of onset of the intrauterine pathogenic insult in the two cases could account for the different clinical pictures. PMID:9053727

  18. Irreversibility of electrical insulating material properties

    OpenAIRE

    Radek Polansky; Vaclav Mentlik

    2007-01-01

    Property changes in electrical insulating materials that appear during repeated voltage stress (e. g. in an applied voltage test) are an often discussed problem. The voltage exposure leads to irreversible changes in a negative sense as this investigation clearly demonstrates. A slow deterioration appears even in the case of the above mentioned applied voltage test when the irreversible effects of particular measurements superimpose. These are the effects of irreversible behavior of the insula...

  19. A class of internally irreversible refrigeration cycles

    Science.gov (United States)

    Ait-Ali, Mohand A.

    1996-03-01

    A Carnot-like irreversible refrigeration cycle is modelled with two isothermal and two non-adiabatic, irreversible processes. The generic source of internal irreversibility, measured by the Clausius inequality, is a general irreversibility term which could include any heat leaks into the Joule - Thompson expansion valve, the evaporator and compressor cold boxes. This cycle is optimized first for maximum refrigeration power and maximum refrigeration load, then for maximum coefficient of performance. Its performances are compared with those of the endoreversible refrigeration cycle, based on a propane stage of a classical cascade liquefaction cycle example. Both cycle models achieve optimum power and maximum refrigeration load at nearly the same refrigeration temperature, but only the coefficient of performance of the irreversible refrigeration cycle reaches a maximum. Moreover, its prediction of heat conductance allocation between evaporator and condenser appears to be not only more conservative, but also more realistic for actual design considerations of refrigeration cycles.

  20. Successful rescue of pure red cell aplasia in two aged patients undergoing pancrease-kindey transplantation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yin-fu; YANG Tong-han; WANG Qing-yu; Wang Ping-xian; Fan Ming-qi; Feng Jia-yu

    2001-01-01

    To explore the correlation between hypoimmunity and the occurrence of pure red cell aplasia (PRCA) in senile patients undergoing combined pancrease-kindey transplantation. Methods: PRCA occurred in 2 patients out of 5 who were performed combined pancrease-kindey transplantation.The general scheme of treatment mainly included selective administration of immunosuppressants and antivirus drugs, infusion of red blood cells on the basis of surveillance of parvorirus B19 and the ratio of T4 and T8 as well as the changes of the myelogram.Results: The myelogram of the patients returned to normal in 2 and 3 weeks after operation, respectively, and subsequent follow-up revealed no recurrence. Conclusion: This series illustrate the point that advanced age, hypo immunity, parvorirus B19 and immunosuppressants are vulnerable to PRCA. Combined treatment is an effectiveremedy for these patients.

  1. Post renal transplant pure red cell aplasia-is tacrolimus a culprit?

    Science.gov (United States)

    Patil, Malagouda R; Choudhury, Arpita Roy; Chohwanglim, Manong; Divyaveer, Smita; Mahajan, Chetan; Pandey, Rajendra

    2016-08-01

    Anemia is not uncommon in the post-renal transplant period and has been reported in up to 40% of renal transplant recipients. It is commonly due to drugs and infections. While post-transplantation anemia is usually due to graft dysfunction and drugs such as mycophenolate and cotrimoxazole, tacrolimus is an uncommon cause. Tacrolimus is usually not believed to be significantly myelosuppressive, but it can cause anemia due to thrombotic microangiopathy. A literature review shows a very small number of reported cases of pure red cell aplasia (PRCA) where tacrolimus seemed to be a causative agent. We report a case series of three renal transplant recipients who were on tacrolimus and presented with chronic transfusion requiring anemia due to PRCA. PMID:27478605

  2. Application of Irreversible Thermodynamics to Distillation

    Directory of Open Access Journals (Sweden)

    Signe Kjelstrup

    2004-09-01

    Full Text Available We compare three different ways of modelling tray distillation to each other, and to experimental data: the most common way that assumes equilibrium between the liquid and vapour phases at the outlets of each tray, and two more precise methods that use irreversible thermodynamics. Irreversible thermodynamics determines the driving forces and fluxes of a system in agreement with the second law. It is shown that the methods using irreversible thermodynamics (Maxwell-Stefan equations are superior to the method that assumes that equilibrium is reached on each tray. The Soret effect must be included to have a good description of the heat flux.

  3. MURCS (Müllerian duct aplasia-renal agenesis-cervicothoracic somite dysplasia): a rare cause of primary amenorrhoea.

    Science.gov (United States)

    Kumar, Sunil; Sharma, Shruti

    2016-04-01

    The agenesis of the Müllerian duct is the second most common cause of primary amenorrhoea after Turner syndrome. The abnormal development of Müllerian duct often associates with the urinary tract and skeletal abnormalities. MURCS (Müllerian duct aplasia-renal agenesis-cervicothoracic somite dysplasia) association is a unique and rare developmental disorder with four common features of uterine hypoplasia or aplasia, renal agenesis or ectopy, vertebral anomalies and short stature. We report a case of young female with primary amenorrhoea. She had well-developed secondary sexual characteristics along with multiple congenital developmental abnormalities such as the absence of uterus, ectopic kidney, cervical vertebral fusion, hemivertebrae, scoliosis, cervical rib, facial asymmetry and growth retardation. Our case highlights the rarity and clinical importance of this syndrome. For the evaluation of primary amenorrhoea in a female with well-developed secondary sexual characteristics, congenital anomalies should be ruled out before hormone and karyotype analyses. PMID:27099773

  4. Incidental finding of unilateral isolated aplasia of serratus anterior muscle and winged scapula on chest radiograph: A case report

    International Nuclear Information System (INIS)

    The isolated aplasia of the serratus anterior muscle with winging of scapula is very rare, and only a few cases are reported. Here, we present a case of a 30-year-old Korean male who initially presented with a left flank pain. His physical exam did not show any significant finding in his right shoulder. However, his chest radiograph showed absence of right serratus anterior muscle and slightly elevated and medially rotated right scapula. Subsequent CT scan showed the right serratus anterior muscle aplasia and medial winging of the right scapula. This case is unique in two aspects. First, the combination of abnormalities is different from the typical congenital abnormalities involving shoulder girdle, such as Sprengel deformity or Poland syndrome. Secondly, this was incidentally diagnosed with chest radiograph, without clinical impression. Careful reading of chest radiograph can help the radiologists to detect such clinically silent abnormalities.

  5. Does an irreversible chemical cycle support equilibrium?

    CERN Document Server

    Banerjee, Kinshuk

    2013-01-01

    The impossibility of attaining equilibrium for cyclic chemical reaction networks with irreversible steps is apparently due to a divergent entropy production rate. A deeper reason seems to be the violation of the detailed balance condition. In this work, we discuss how the standard theoretical framework can be adapted to include irreversible cycles, avoiding the divergence. With properly redefined force terms, such systems are also seen to reach and sustain equilibria that are characterized by the vanishing of the entropy production rate, though detailed balance is not maintained. Equivalence of the present formulation with Onsager's original prescription is established for both reversible and irreversible cycles, with a few adjustments in the latter case. Further justification of the attainment of true equilibrium is provided with the help of the minimum entropy production principle. All the results are generalized for an irreversible cycle comprising of N number of species.

  6. Irreversible thermodynamics of Poisson processes with reaction.

    Science.gov (United States)

    Méndez, V; Fort, J

    1999-11-01

    A kinetic model is derived to study the successive movements of particles, described by a Poisson process, as well as their generation. The irreversible thermodynamics of this system is also studied from the kinetic model. This makes it possible to evaluate the differences between thermodynamical quantities computed exactly and up to second-order. Such differences determine the range of validity of the second-order approximation to extended irreversible thermodynamics.

  7. Irreversible thermodynamics of Poisson processes with reaction

    Science.gov (United States)

    Méndez, Vicenç; Fort, Joaquim

    1999-11-01

    A kinetic model is derived to study the successive movements of particles, described by a Poisson process, as well as their generation. The irreversible thermodynamics of this system is also studied from the kinetic model. This makes it possible to evaluate the differences between thermodynamical quantities computed exactly and up to second-order. Such differences determine the range of validity of the second-order approximation to extended irreversible thermodynamics.

  8. Further development of a model of chronic bone marrow aplasia in the busulphan-treated mouse.

    Science.gov (United States)

    Turton, John A; Sones, William R; Andrews, Charles M; Pilling, Andrew M; Williams, Thomas C; Molyneux, Gemma; Rizzo, Sian; Gordon-Smith, Edward C; Gibson, Frances M

    2006-02-01

    Aplastic anaemia (AA) in man is an often fatal disease characterized by pancytopenia of the peripheral blood and aplasia of the bone marrow. AA is a toxic effect of many drugs and chemicals (e.g. chloramphenicol, azathioprine, phenylbutazone, gold salts, penicillamine and benzene). However, there are no widely used or convenient animal models of drug-induced AA. Recently, we reported a new model of chronic bone marrow aplasia (CBMA = AA) in the busulphan (BU)-treated mouse: eight doses of BU (10.50 mg/kg) were administered to female BALB/c mice over a period of 23 days; CBMA was evident at day 91/112 post-dosing with significantly reduced erythrocytes, platelets, leucocytes and nucleated bone marrow cell counts. However, mortality was high (49.3%). We have now carried out a study to modify the BU-dosing regime to induce CBMA without high mortality, and investigated the patterns of cellular responses in the blood and marrow in the post-dosing period. Mice (n = 64/65) were dosed 10 times with BU at 0 (vehicle control), 8.25, 9.0 and 9.75 mg/kg over 21 days and autopsied at day 1, 23, 42, 71, 84, 106 and 127 post-dosing (n = 7-15); blood and marrow samples were examined. BU induced a predictable bone marrow depression at day 1 post-dosing; at day 23/42 post-dosing, parameters were returning towards normal during a period of recovery. At day 71, 84, 106 and 127 post-dosing, a stabilized, late-stage, nondose-related CBMA was evident in BU-treated mice, with decreased erythrocytes, platelets and marrow cell counts, and increased MCV. At day 127 post-dosing, five BU-treated mice showed evidence of lymphoma. In this study, mortality was low, ranging from 3.1% (8.25 mg/kg BU) to 12.3% (9.75 mg/kg BU). It is concluded that BU at 9.0 mg/kg (or 9.25 mg/kg) is an appropriate dose level to administer (10 times over 21 days) to induce CBMA at approximately day 50-120 post-dosing.

  9. Spontaneous hematologic recovery from bone marrow aplasia after accidental tenfold overdosage with radiophosphorus

    Energy Technology Data Exchange (ETDEWEB)

    Gmuer, J.; Bischof, B.; Coninx, S.; Bucher, U.; Poretti, G.; Henrichs, K.; Kaul, A.; Roedler, H.D.; Buettner, K.; Frick, P.G.

    1983-04-01

    Two patients with polycythemia vera received intravenously an accidental tenfold overdosage of radiophosphorus therapy (60 and 50 mCi 32P, respectively). In both patients, the occurrence of hemorrhagic complications 3 wk after the 32P medication led to detection of the error and referral to our hospital. Upon admission they showed an agranulocytosis, severe thrombocytopenia, and bone marrow aplasia. In both cases, spontaneous recovery of the hematopoiesis was observed from day 40 posttreatment onward. In one patient, a slow but ultimately complete normalization of blood counts and marrow morphology took place, whereas in the other, a mild thrombocytopenia persists. Nearly 5 yr after the accidental overdosage, both patients are clinically well. Symptoms of polycythemia vera have not reappeared up to now. Attempts were made to evaluate the radiation dose absorbed by the bone marrow. In the first patient, the daily 32P excretion was determined from day 22 to day 60, whereas in the other patient a whole body count was performed on day 78 after administration. From these results, an approximate cumulative bone marrow dose of 10 Sv (1000 rem) could be calculated.

  10. Common crus aplasia: diagnosis by 3D volume rendering imaging using 3DFT-CISS sequence

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H.J. E-mail: hakjink@pusan.ac.kr; Song, J.W.; Chon, K.-M.; Goh, E.-K

    2004-09-01

    AIM: The purpose of this study was to evaluate the findings of three-dimensional (3D) volume rendering (VR) imaging in common crus aplasia (CCA) of the inner ear. MATERIALS AND METHODS: Using 3D VR imaging of temporal bone constructive interference in steady state (CISS) magnetic resonance (MR) images, we retrospectively reviewed seven inner ears of six children who were candidates for cochlear implants and who had been diagnosed with CCA. As controls, we used the same method to examine 402 inner ears of 201 patients who had no clinical symptoms or signs of sensorineural hearing loss. Temporal bone MR imaging (MRI) was performed with a 1.5 T MR machine using a CISS sequence, and VR of the inner ear was performed on a work station. Morphological image analysis was performed on rotation views of 3D VR images. RESULTS: In all seven cases, CCA was diagnosed by the absence of the common crus. The remaining superior semicircular canal (SCC) was normal in five and hypoplastic in two inner ears, while the posterior SCC was normal in all seven. One patient showed bilateral symmetrical CCA. Complicated combined anomalies were seen in the cochlea, vestibule and lateral SCC. CONCLUSION: 3D VR imaging findings with MR CISS sequence can directly diagnose CCA. This technique may be useful in delineating detailed anomalies of SCCs.

  11. Unilateral multifocal testicular biopsies in 320 patients with germ cell aplasia

    Directory of Open Access Journals (Sweden)

    D Jamali Zavareii. M

    2007-05-01

    Full Text Available Background: Germ cell aplasia (G.C.A is one of the most important testicular causes of infertility and azospermia.In this condition the seminiferous tubules are only lined by a single layer of sertoli cell. In some cases, there is focal area with spermatogenic activity. Methods: We studied infertile men with G.C.A referred to Jahade Daneshgahi of Iran during 1381-82, retrospectively. All the cases had more than one biopsy of one testis. Results: In 11.6٪ of 320 cases, comparison of multiple biopsy sites of a testis revealed: when one site showed G.C.A, another site revealed areas with spermatogenic activity. Considering the cases who showed germ cells in both sites, 15.3٪ of cases multiple biopsy sites appeared to have focal spermatogenesis, better maturation of germ cells or higher scoring area for urologic operation. Conclusion: According to new techniques in treatment of infertility with ICSI (intra cytoplasmic sperm injection in which fertility is possible with one spermatozoa or even spermatid (after recovery, biopsy of multiple sites instead of only one site is highly recommended in azospermic patient.

  12. Time and irreversibility in an accelerating universe

    CERN Document Server

    Romero, Gustavo E

    2011-01-01

    It is a remarkable fact that all processes occurring in the observable Universe are irreversible, whereas the equations through which the fundamental laws of physics are formulated are invariant under time reversal. The emergence of irreversibility from the fundamental laws has been a topic of consideration by physicists, astronomers and philosophers since Boltzmann's formulation of his famous "H" theorem. In this paper we shall discuss some aspects of this problem and its connection with the dynamics of space-time, within the framework of modern cosmology. We conclude that the existence of cosmological horizons allows a coupling of the global state of the Universe with the local events determined through electromagnetic processes.

  13. Efficiency of Rectification: Reversible vs. Irreversible Regimes

    Science.gov (United States)

    Sokolov, I. M.

    2002-11-01

    Both man-made locomotive devices and molecular motors use gears to transform a reciprocating motion into a directed one. One of the most common gears is a rectifier, a mechanically irreversible appliance. The maximal energetic efficiency of an isothermic gear is bounded by unity, as a consequence of the Second Law. However, approaching this ideal efficiency does not imply approaching reversibility. We discuss what properties of a rectifier mostly influence the transduction efficiency and show that an appliance which locks under backward force is just the one which can approach the ideal efficiency either in the reversible or in the irreversible regime.

  14. Risk Aversion, Price Uncertainty and Irreversible Investments

    NARCIS (Netherlands)

    van den Goorbergh, R.W.J.; Huisman, K.J.M.; Kort, P.M.

    2003-01-01

    This paper generalizes the theory of irreversible investment under uncertainty by allowing for risk averse investors in the absence of com-plete markets.Until now this theory has only been developed in the cases of risk neutrality, or risk aversion in combination with complete markets.Within a gener

  15. The reverse control of irreversible biological processes.

    Science.gov (United States)

    Cho, Kwang-Hyun; Joo, Jae Il; Shin, Dongkwan; Kim, Dongsan; Park, Sang-Min

    2016-09-01

    Most biological processes have been considered to be irreversible for a long time, but some recent studies have shown the possibility of their reversion at a cellular level. How can we then understand the reversion of such biological processes? We introduce a unified conceptual framework based on the attractor landscape, a molecular phase portrait describing the dynamics of a molecular regulatory network, and the phenotype landscape, a map of phenotypes determined by the steady states of particular output molecules in the attractor landscape. In this framework, irreversible processes involve reshaping of the phenotype landscape, and the landscape reshaping causes the irreversibility of processes. We suggest reverse control by network rewiring which changes network dynamics with constant perturbation, resulting in the restoration of the original phenotype landscape. The proposed framework provides a conceptual basis for the reverse control of irreversible biological processes through network rewiring. WIREs Syst Biol Med 2016, 8:366-377. doi: 10.1002/wsbm.1346 For further resources related to this article, please visit the WIREs website. PMID:27327189

  16. Markov Chain Monte Carlo and Irreversibility

    Science.gov (United States)

    Ottobre, Michela

    2016-06-01

    Markov Chain Monte Carlo (MCMC) methods are statistical methods designed to sample from a given measure π by constructing a Markov chain that has π as invariant measure and that converges to π. Most MCMC algorithms make use of chains that satisfy the detailed balance condition with respect to π; such chains are therefore reversible. On the other hand, recent work [18, 21, 28, 29] has stressed several advantages of using irreversible processes for sampling. Roughly speaking, irreversible diffusions converge to equilibrium faster (and lead to smaller asymptotic variance as well). In this paper we discuss some of the recent progress in the study of nonreversible MCMC methods. In particular: i) we explain some of the difficulties that arise in the analysis of nonreversible processes and we discuss some analytical methods to approach the study of continuous-time irreversible diffusions; ii) most of the rigorous results on irreversible diffusions are available for continuous-time processes; however, for computational purposes one needs to discretize such dynamics. It is well known that the resulting discretized chain will not, in general, retain all the good properties of the process that it is obtained from. In particular, if we want to preserve the invariance of the target measure, the chain might no longer be reversible. Therefore iii) we conclude by presenting an MCMC algorithm, the SOL-HMC algorithm [23], which results from a nonreversible discretization of a nonreversible dynamics.

  17. Mathematical Models and Equilibrium in Irreversible Microeconomics

    OpenAIRE

    Anatoly M. Tsirlin; Sergey A. Amelkin

    2010-01-01

    A set of equilibrium states in a system consisting of economic agents, economic reservoirs, and firms is considered. Methods of irreversible microeconomics are used. We show that direct sale/purchase leads to an equilibrium state which depends upon the coefficients of supply/demand functions. To reach the unique equilibrium state it is necessary to add either monetary exchange or an intermediate firm.

  18. GROUPOIDS AND IRREVERSIBLE DISCRETE DYNAMICAL SYSTEMS II

    Directory of Open Access Journals (Sweden)

    Mădălina Roxana Buneci

    2012-05-01

    Full Text Available The purpose of this paper is to study the topology of the orbit space of an irreversible discrete dynamical system (X,  seen as a principal groupoid associated to the groupoid G(X,,E introduced in [1] (where E is an equivalence relation on X.

  19. Epoetin-associated pure red cell aplasia: past, present, and future considerations

    Science.gov (United States)

    McKoy, June M.; Stonecash, Robin E.; Cournoyer, Denis; Rossert, Jerome; Nissenson, Allen R.; Raisch, Dennis W.; Casadevall, Nicole; Bennett, Charles L.

    2009-01-01

    BACKGROUND Since 1988, millions of patients have received epoetin products intravenously (IV) and subcutaneously. In 1998, epoetin-associated pure red cell aplasia (PRCA) was first reported and causation was attributed to formulations without human serum albumin (HSA), subcutaneous administration, and uncoated rubber stoppers. STUDY DESIGN AND METHODS Data on erythropoietin (EPO)-associated PRCA were obtained from the Food and Drug Administration (FDA), regulatory authorities in other countries, and the manufacturers of epoetin alfa, epoetin beta, and darbepoetin. The data included information on numbers of PRCA cases and estimated exposure-adjusted incidence rates by EPO product, anemia etiology, administration route, country of PRCA identification, and date reported. RESULTS In 1999, academicians in Paris identified 12 EPO-treated patients with antibody-mediated PRCA; 11 of these patients were on hemodialysis and had received subcutaneous Eprex (Johnson & Johnson). In 2002, authorities in Europe, Australia, Singapore, and Canada mandated Eprex by IV route to hemodialysis patients, and the relevant manufacturers added Teflon coating to prefilled syringes of Eprex; PRCA cases subsequently decreased by 90 percent. By 2003, 180 Eprex-associated PRCA cases were identified in Europe, Canada, Australia, and Asia, despite improvements in handling. Since 2002, FDA safety databases include information on 59 new cases of antibody-associated PRCA, primarily associated with subcutaneous epoetin alfa and darbepoetin that does not contain HSA. CONCLUSION Independent actions by regulatory authorities, manufacturers, and academic researchers identified significant numbers of PRCA cases between 1998 and 2003 and characterized the probable etiology. Today, antibody-mediated PRCA is an infrequent class toxicity occurring among some hemodialysis patients on EPOs. PMID:18482185

  20. A patient with isochromosome 18q, radial-thumb aplasia, thrombocytopenia, and an unbalanced 10;18 chromosome translocation.

    Science.gov (United States)

    Sahoo, Trilochan; Naeem, Rizwan; Pham, Kim; Chheng, Sou; Noblin, Sarah T; Bacino, Carlos A; Gambello, Michael J

    2005-02-15

    We report on the clinical and cytogenetic findings in a newborn with a de novo isochromosome 18q. Radial/thumb aplasia and thrombocytopenia were significant features in addition to multiple congenital anomalies. Comparison with reported cases suggests that the genes for such features are located on the 18q arm. An additional finding of a non-reciprocal translocation between chromosome 18p telomere and chromosome 10q telomere was also observed in a majority of cells examined. This additional rearrangement likely has minimal phenotypic consequences, but does raise the possibility that cryptic translocations of telomeric ends of the deleted arm in isochromosome cases may be more common than appreciated.

  1. Dapsone-induced pure red cell aplasia and cholestatic jaundice: A new experience for diagnosis and management.

    Science.gov (United States)

    Sawlani, Kamal Kumar; Chaudhary, Shyam Chand; Singh, Jitendra; Raja, Deep Chandh; Mishra, Sanjay; Goel, Madhu Mati

    2016-01-01

    Dapsone (4,4'- diaminodiphenylsulfone) is the parent compound of the sulfones, and it has potent antiparasitic, anti-inflammatory, and immunomodulatory effects. It is used in the treatment of leprosy, dermatitis herpetiformis, and prophylactically to prevent Pneumocystis pneumonia and toxoplasmosis in patients unable to tolerate trimethoprim with sulfamethoxazole. We hereby report a case of dapsone toxicity who developed pure red cell aplasia and cholestatic jaundice in a suspected case of dermatitis herpetiformis. Patient had an excellent response to corticosteroids after withdrawal of dapsone. PMID:27512715

  2. Noncanonical Wnt5a-Ca(2+) -NFAT signaling axis in pesticide induced bone marrow aplasia mouse model: A study to explore the novel mechanism of pesticide toxicity.

    Science.gov (United States)

    Chattopadhyay, Sukalpa; Chatterjee, Ritam; Law, Sujata

    2016-10-01

    According to case-control studies, long-term pesticide exposure can cause bone marrow aplasia like hematopoietic degenerative disease leading to impaired hematopoiesis and increased risk of aplastic anemia in human subjects. However, the exact mechanism of pesticide mediated hematotoxicity still remains elusive. In this study, we investigated the role of noncanonical Wnt signaling pathway, a crucial regulator of adult hematopoiesis, in pesticide induced bone marrow aplasia mouse model. Aplasia mouse model was developed following inhalation and dermal exposure of 5% aqueous mixture of common agriculturally used pesticides for 6 h/day for 5 days a week up to 90 days. After that, blood hemogram, marrow smear, cellularity, scanning electron microscopy, extramedullary hematopoiesis and flowcytometric expression analysis of noncanonical Wnt signaling components, such as Wnt 5a, fzd5, NFAT, IFN-γ, intracellular Ca(2+) level were evaluated in the bone marrow hematopoietic stem/progenitor compartment of the control and pesticide induced aplasia groups of animals. Results showed that pesticide exposed mice were anemic with peripheral blood pancytopenia, hypocellular degenerative marrow, and extramedullary hematopoiesis in the spleen. Upon pesticide exposure, Wnt 5a expression was severely downregulated with a decline in intracellular Ca(2+) level. Moreover, downstream of Wnt5a, we observed sharp downregulation of NFATc2 transcription factor expression, the major target of pesticide toxicity and its target molecule IFN-γ. Taken together, our result suggests that deregulation of Wnt5a-Ca(2+) -NFAT signaling axis in the hematopoietic stem/progenitor compartment plays a crucial role behind the pathogenesis of pesticide mediated bone marrow aplasia by limiting primitive hematopoietic stem cells' ability to maintain hematopoietic homeostasis and reconstitution mechanism in vivo during xenobiotic stress leading to ineffective hematopoiesis and evolution of bone marrow aplasia.

  3. Hematopoiesis stimulation test by interleukin 1α gene transfer in the Cynomolgus macaque: application to secondary medullary aplasia from an accidental irradiation

    International Nuclear Information System (INIS)

    After a description of the context of medullary aplasia (haematological radiobiology, radiation acute syndrome, therapeutic care), and an overview of knowledge about the interleukin-1 and medullary stroma cells, this research thesis aims at investigating therapeutic alternatives for radio-accidental aplasia. More precisely, it aims at defining means to get cytokines which are efficient for haematopoiesis. Interleukin-1 is chosen for its properties and tests are performed on a macaque with two approaches for gene transfer: an ex vivo transfer by retroviral vector enabling an integration in the target cell genome, and an in situ transfer by adeno-viral vector directly applied in the animal osseous medulla

  4. Mathematical models and equilibrium in irreversible microeconomics

    Directory of Open Access Journals (Sweden)

    Anatoly M. Tsirlin

    2010-07-01

    Full Text Available A set of equilibrium states in a system consisting of economic agents, economic reservoirs, and firms is considered. Methods of irreversible microeconomics are used. We show that direct sale/purchase leads to an equilibrium state which depends upon the coefficients of supply/demand functions. To reach the unique equilibrium state it is necessary to add either monetary exchange or an intermediate firm.

  5. Simulations of kinetically irreversible protein aggregate structure.

    OpenAIRE

    Patro, S Y; Przybycien, T M

    1994-01-01

    We have simulated the structure of kinetically irreversible protein aggregates in two-dimensional space using a lattice-based Monte-Carlo routine. Our model specifically accounts for the intermolecular interactions between hydrophobic and hydrophilic protein surfaces and a polar solvent. The simulations provide information about the aggregate density, the types of inter-monomer contacts and solvent content within the aggregates, the type and extent of solvent exposed perimeter, and the short-...

  6. Water Management in France: Delegation and Irreversibility

    OpenAIRE

    Ephraim Clark; Gérard Mondello

    2000-01-01

    The problem that we address in this paper stems from the trend to delegation in the water management field. It refers to the municipality’s negotiating disadvantage in the face of cartelized water management firms that makes delegation, once undertaken, virtually irreversible. We show why the characteristics of the delegation auction render is useless as a tool for collective welfare maximization. We also show that the remaining tool for achieving collective welfare maximization, i.e. the mun...

  7. Metrics and Energy Landscapes in Irreversible Thermodynamics

    OpenAIRE

    Bjarne Andresen

    2015-01-01

    We describe how several metrics are possible in thermodynamic state space but that only one, Weinhold’s, has achieved widespread use. Lengths calculated based on this metric have been used to bound dissipation in finite-time (irreversible) processes be they continuous or discrete, and described in the energy picture or the entropy picture. Examples are provided from thermodynamics of heat conversion processes as well as chemical reactions. Even losses in economics can be bounded using a therm...

  8. Extended irreversible thermodynamics revisited (1988-98)

    Science.gov (United States)

    Jou, D.; Casas-Vázquez, J.; Lebon, G.

    1999-07-01

    We review the progress made in extended irreversible thermodynamics during the ten years that have elapsed since the publication of our first review on the same subject (Rep. Prog. Phys. 1988 51 1105 - 72). During this decade much effort has been devoted to achieving a better understanding of the fundamentals and a broadening of the domain of applications. The macroscopic formulation of extended irreversible thermodynamics is reviewed and compared with other non-equilibrium thermodynamic theories. The foundations of EIT are discussed on the bases of information theory, kinetic theory, stochastic phenomena and computer simulations. Several significant applications are presented, some of them of considerable practical interest (non-classical heat transport, polymer solutions, non-Fickian diffusion, microelectronic devices, dielectric relaxation), and some others of special theoretical appeal (superfluids, nuclear collisions, cosmology). We also outline some basic problems which are not yet completely solved, such as the definitions of entropy and temperature out of equilibrium, the selection of the relevant variables, and the status to be reserved to the H-theorem and its relation to the second law. In writing this review, we had four objectives in mind: to show (i) that extended irreversible thermodynamics stands at the frontiers of modern thermodynamics; (ii) that it opens the way to new and useful applications; (iii) that much progress has been achieved during the last decade, and (iv) that the subject is far from being exhausted.

  9. An action principle of classical irreversible thermodynamics - Irreversible thermodynamic cycles and embodied bits of information

    CERN Document Server

    Hanel, Rudolf A

    2016-01-01

    Despite its simplicity, it seems to my best of knowledge that the possibly simplest approach towards deriving equations governing irreversible thermodynamics from gas-kinetic considerations within the framework of classical mechanics has never been pursued. In this paper we address this omission and derive the equations describing the irreversible thermodynamics of a gas in a piston and associated thermodynamic cycles performed in finite time. What we find is a thermodynamic action principle: The irreversible work we require for performing a thermodynamic cycle in finite time times the time we require to run through the cycle, a isothermal compression/decompression cycle for instance, will always be larger or equal to a lower bound given by a system specific constant with the dimension of an action. This process specific action constants can take values of the order of Plank's constant for microscopic processes, such as displacing a Hydrogen atom by one atom diameter. For macroscopic processes (e.g. a bicycle...

  10. Thermodynamics of irreversible plant cell growth

    Directory of Open Access Journals (Sweden)

    Mariusz Pietruszka

    2011-04-01

    Full Text Available The time-irreversible cell enlargement of plant cells at a constant temperature results from two independent physical processes, e.g. water absorption and cell wall yielding. In such a model cell growth starts with reduction in wall stress because of irreversible extension of the wall. The water absorption and physical expansion are spontaneous consequences of this initial modification of the cell wall (the juvenile cell vacuolate, takes up water and expands. In this model the irreversible aspect of growth arises from the extension of the cell wall. Such theory expressed quantitatively by time-dependent growth equation was elaborated by Lockhart in the 60's.The growth equation omit however a very important factor, namely the environmental temperature at which the plant cells grow. In this paper we put forward a simple phenomenological model which introduces into the growth equation the notion of temperature. Moreover, we introduce into the modified growth equation the possible influence of external growth stimulator or inhibitor (phytohormones or abiotic factors. In the presence of such external perturbations two possible theoretical solutions have been found: the linear reaction to the application of growth hormones/abiotic factors and the non-linear one. Both solutions reflect and predict two different experimental conditions, respectively (growth at constant or increasing concentration of stimulator/inhibitor. The non-linear solution reflects a common situation interesting from an environmental pollution point of view e.g. the influence of increasing (with time concentration of toxins on plant growth. Having obtained temperature modified growth equations we can draw further qualitative and, especially, quantitative conclusions about the mechanical properties of the cell wall itself. This also concerns a new and interesting result obtained in our model: We have calculated the magnitude of the cell wall yielding coefficient (T [m3 J-1•s-1] in

  11. Irreversible electroporation: state of the art

    Directory of Open Access Journals (Sweden)

    Wagstaff PGK

    2016-04-01

    Full Text Available Peter GK Wagstaff,1 Mara Buijs,1 Willemien van den Bos,1 Daniel M de Bruin,2 Patricia J Zondervan,1 Jean JMCH de la Rosette,1 M Pilar Laguna Pes1 1Department of Urology, 2Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, the Netherlands Abstract: The field of focal ablative therapy for the treatment of cancer is characterized by abundance of thermal ablative techniques that provide a minimally invasive treatment option in selected tumors. However, the unselective destruction inflicted by thermal ablation modalities can result in damage to vital structures in the vicinity of the tumor. Furthermore, the efficacy of thermal ablation intensity can be impaired due to thermal sink caused by large blood vessels in the proximity of the tumor. Irreversible electroporation (IRE is a novel ablation modality based on the principle of electroporation or electropermeabilization, in which electric pulses are used to create nanoscale defects in the cell membrane. In theory, IRE has the potential of overcoming the aforementioned limitations of thermal ablation techniques. This review provides a description of the principle of IRE, combined with an overview of in vivo research performed to date in the liver, pancreas, kidney, and prostate. Keywords: irreversible electroporation, IRE, tumor, ablation, focal therapy, cancer

  12. Magnetic Irreversibility in VO2/Ni Bilayers

    Science.gov (United States)

    de La Venta, Jose; Lauzier, Josh; Sutton, Logan

    The temperature dependence of the coercivity and magnetization of VO2/Ni bilayers was studied. VO2 exhibits a well-known Structural Phase Transition (SPT) at 330-340 K, from a low temperature monoclinic (M) to a high temperature rutile (R) structure. The SPT of VO2 induces an inverse magnetoelastic effect that strongly modifies the coercivity and magnetization of the Ni films. In addition, the growth conditions allow tuning of the magnetic properties. Ni films deposited on top of VO2 (M) show an irreversible change in the coercivity after the first cycle through the high temperature phase, with a corresponding change in the surface morphology of VO2. On the other hand, the Ni films grown on top of VO2 (R) do not show this irreversibility. These results indicate that properties of magnetic films are strongly affected by the strain induced by materials that undergo SPT and that it is possible to control the magnetic properties by tuning the growth conditions.

  13. Probabilistic Gompertz model of irreversible growth.

    Science.gov (United States)

    Bardos, D C

    2005-05-01

    Characterizing organism growth within populations requires the application of well-studied individual size-at-age models, such as the deterministic Gompertz model, to populations of individuals whose characteristics, corresponding to model parameters, may be highly variable. A natural approach is to assign probability distributions to one or more model parameters. In some contexts, size-at-age data may be absent due to difficulties in ageing individuals, but size-increment data may instead be available (e.g., from tag-recapture experiments). A preliminary transformation to a size-increment model is then required. Gompertz models developed along the above lines have recently been applied to strongly heterogeneous abalone tag-recapture data. Although useful in modelling the early growth stages, these models yield size-increment distributions that allow negative growth, which is inappropriate in the case of mollusc shells and other accumulated biological structures (e.g., vertebrae) where growth is irreversible. Here we develop probabilistic Gompertz models where this difficulty is resolved by conditioning parameter distributions on size, allowing application to irreversible growth data. In the case of abalone growth, introduction of a growth-limiting biological length scale is then shown to yield realistic length-increment distributions.

  14. Aplasia medular após transplante hepático em pediatria Aplastic anemia after pediatric liver transplantation

    Directory of Open Access Journals (Sweden)

    Marlene P. Garanito

    2009-01-01

    Full Text Available A aplasia de medula é uma das mais raras (Aplastic anemia (AA is one of the rarest (<1% and most serious complications of liver transplantation for fulminant non-A, non-B and non-C hepatitis. It was first described in 1987 by Stock; the mechanism involved is an immunologically mediated condition secondary to an unknown viral infection. The disease is associated with a dismal prognosis. Spontaneous recovery from acquired AA is very rare however some patients (50-70% recover after immunosuppressive therapy, such as Cyclosporin A (CsA and Antithymocyte globulin (ATG, even after liver transplantation. Another treatment option is bone marrow transplantation. We report on a child who developed AA following liver transplantation for fulminant viral hepatitis that was treated with intensive immunosuppression including CsA and ATG and achieved complete recovery.

  15. A rare presentation of aplasia cutis congenita after feto-reduction in a trichorionic-triamniotic pregnancy.

    Science.gov (United States)

    Vettori, D J; Jairath, P

    2015-01-01

    Aplasia cutis congenita (ACC) is rare skin disorder of newborns that has been linked to both assisted reproductive technology (ART) and feto-reduction procedures. ACC is characterized by well-demarcated lesions that are devoid of all skin layers. Group-V ACC presents with a distinctive and symmetrical distribution pattern. It is thought to result from an insult to the fetus after concomitant twin demise and is almost exclusively reported in monochorionic gestations.A 41-year-old female with an in vitro fertilization (IVF) assisted tri-chorionic gestation subsequently underwent selective feto-reduction of Fetus C. The patient delivered two pre-term neonates secondary to pre-eclampsia. The initial exam of Twin B showed extensive, well-demarcated, symmetrical areas devoid of any skin over the anterior and lateral trunk, extending up the lateral thoracic walls. Chest and abdominal viscera were visible through a thin fibrous membrane. The skin defects were managed conservatively with twice-daily dressings of Aquaphor, and Vaseline gauze. The areas of aplasia slowly contracted, though residual scarring was noted. After four weeks in the NICU, most of the areas were healed.ACC in multi-fetal pregnancies is a rare, but well-described complication. This is, to our knowledge, the first reported case in a tri-chorionic IVF gestation after feto-reduction. With increased incidence of ART-associated pregnancies and the use of feto-reduction for higher order gestations, this may become more common. Neonates often require specialized intensive care. Conservative management usually will suffice, although surgical grafting may be required. Physicians should be aware of this condition and counsel their feto-reduction patients of the risk. PMID:26485557

  16. The Value of Fighting Irreversible Demise by Softening the Irreversible Cost

    NARCIS (Netherlands)

    Magis, P.; Sbuelz, A.

    2005-01-01

    We study a novel issue in the real-options-based technology innovation literature by means of double barrier contingent claims analysis.We show how much a ¯rm with the monopoly over a project is willing to spend in investment technology innovation that softens the irreversible cost of accessing the

  17. Bacterial, fungal and yeast contamination in six brands of irreversible hydrocolloid impression materials Contaminação por bactérias, fungos e leveduras em seis marcas comerciais de materiais de moldagem à base de hidrocolóide irreversível

    Directory of Open Access Journals (Sweden)

    Luciana Assirati Casemiro

    2007-06-01

    Full Text Available This study assessed the level of contamination of six commercially available irreversible hydrocolloids (two containing chlorhexidine and identified the contamination present in the materials. Petri dishes containing selective and enriched culture media were inoculated with alginate powder (0.06 g, in triplicate. After incubation (37°C/7 days, the colony-forming units (CFU were counted and Gram stained. Biochemical identification of the different morphotypes was also performed. The contamination levels for the materials were: Jeltrate - 389 CFU/g; Jeltrate Plus - 516 CFU/g; Jeltrate Chromatic - 135 CFU/g; Hydrogum - 1,455 CFU/g; Kromopan - 840 CFU/g; and Greengel - 59 CFU/g. Gram staining revealed the presence of Gram-positive bacillus and Gram-positive cocci. The bacteria Staphylococcus epidermidis, Bacillus subtilis, Bacillus sp., Bacillus coagulans, Bacillus licheniformis, Bacillus cereus, Micrococcus luteus, and Nocardia sp.; the filamentous fungi Aspergillus niger, Aspergillus flavus, Rhizopus sp., Neurospora sp.; and the yeast Candida sp. were isolated. The contamination detected in the impression materials points out the need for adopting measures to improve the microbiological quality of these materials. The use of contaminated materials in the oral cavity goes against the basic principles for controlling cross-contamination and may represent a risk for debilitated or immunocompromised patients.Este estudo avaliou o nível de contaminação de seis marcas comerciais de alginato (duas contendo clorexidina e identificou a contaminação presente nesses materiais. Alíquotas de alginato (0,06 g foram semeadas em meios de cultura seletivos e enriquecidos, em triplicata. Após incubação (37°C/7 dias, as unidades formadoras de colônia (UFC foram contadas e foram realizadas as identificações morfotintorial (Gram e bioquímica. Os níveis de contaminação dos materiais foram: Jeltrate - 389 UFC/g; Jeltrate Plus - 516 UFC/g; Jeltrate

  18. Irreversible electroporation: state of the art.

    Science.gov (United States)

    Wagstaff, Peter Gk; Buijs, Mara; van den Bos, Willemien; de Bruin, Daniel M; Zondervan, Patricia J; de la Rosette, Jean Jmch; Laguna Pes, M Pilar

    2016-01-01

    The field of focal ablative therapy for the treatment of cancer is characterized by abundance of thermal ablative techniques that provide a minimally invasive treatment option in selected tumors. However, the unselective destruction inflicted by thermal ablation modalities can result in damage to vital structures in the vicinity of the tumor. Furthermore, the efficacy of thermal ablation intensity can be impaired due to thermal sink caused by large blood vessels in the proximity of the tumor. Irreversible electroporation (IRE) is a novel ablation modality based on the principle of electroporation or electropermeabilization, in which electric pulses are used to create nanoscale defects in the cell membrane. In theory, IRE has the potential of overcoming the aforementioned limitations of thermal ablation techniques. This review provides a description of the principle of IRE, combined with an overview of in vivo research performed to date in the liver, pancreas, kidney, and prostate. PMID:27217767

  19. Irreversible Electroporation (IRE) in Renal Tumors.

    Science.gov (United States)

    Narayanan, Govindarajan; Doshi, Mehul H

    2016-02-01

    Small renal masses (SRMs) have been traditionally managed with surgical resection. Minimally invasive nephron-sparing treatment methods are preferred to avoid harmful consequences of renal insufficiency, with partial nephrectomy (PN) considered the gold standard. With increase in the incidence of the SRMs and evolution of ablative technologies, percutaneous ablation is now considered a viable treatment alternative to surgical resection with comparable oncologic outcomes and better nephron-sparing property. Traditional thermal ablative techniques suffer from unique set of challenges in treating tumors near vessels or critical structures. Irreversible electroporation (IRE), with its non-thermal nature and connective tissue-sparing properties, has shown utility where traditional ablative techniques face challenges. This review presents the role of IRE in renal tumors based on the most relevant published literature on the IRE technology, animal studies, and human experience. PMID:26769468

  20. Chemical kinetics, stochastic processes, and irreversible thermodynamics

    CERN Document Server

    Santillán, Moisés

    2014-01-01

    This book brings theories in nonlinear dynamics, stochastic processes, irreversible thermodynamics, physical chemistry, and biochemistry together in an introductory but formal and comprehensive manner.  Coupled with examples, the theories are developed stepwise, starting with the simplest concepts and building upon them into a more general framework.  Furthermore, each new mathematical derivation is immediately applied to one or more biological systems.  The last chapters focus on applying mathematical and physical techniques to study systems such as: gene regulatory networks and ion channels. The target audience of this book are mainly final year undergraduate and graduate students with a solid mathematical background (physicists, mathematicians, and engineers), as well as with basic notions of biochemistry and cellular biology.  This book can also be useful to students with a biological background who are interested in mathematical modeling, and have a working knowledge of calculus, differential equatio...

  1. Diffusion of irreversible energy technologies under uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Cacallo, J.D.; Sutherland, R.J.

    1993-09-01

    This paper presents a model of technology diffusion is consistent with characteristics of participants in most energy markets. Whereas the models used most widely for empirical research are based on the assumption that the extended delays in adoption of cost-saving innovations are the result of either lack of knowledge about the new processes or heterogeneity across potential adopters, the model presented in this paper is based on the strategic behavior by firms. The strategic interdependence of the firms` decisions is rooted in spillover effects associated with an inability to exclude others from the learning-by-doing acquired when a firm implements a new technology. The model makes extensive use of recent developments in investment theory as it relates irreversible investments under uncertainty.

  2. Exergetic sustainability evaluation of irreversible Carnot refrigerator

    Science.gov (United States)

    Açıkkalp, Emin

    2015-10-01

    Purpose of this paper is to assess irreversible refrigeration cycle by using exergetic sustainability index. In literature, there is no application of exergetic sustainability index for the refrigerators and, indeed, this index has not been derived for refrigerators. In this study, exergetic sustainability indicator is presented for the refrigeration cycle and its relationships with other thermodynamics parameters including COP, exergy efficiency, cooling load, exergy destruction, ecological function and work input are investigated. Calculations are conducted for endoreversible and reversible cycles and then results obtained from the ecological function are compared. It is found that exergy efficiency, exergetic sustainable index reduce 47.595% and 59.689% and rising at the COP is 99.888% is obtained for endoreversible cycle. Similarly, exergy efficiency and exergetic sustainability index reduce 90.163% and 93.711% and rising of the COP is equal to 99.362%.

  3. Work Criteria Function of Irreversible Heat Engines

    Directory of Open Access Journals (Sweden)

    Mahmoud Huleihil

    2014-01-01

    Full Text Available The irreversible heat engine is reconsidered with a general heat transfer law. Three criteria known in the literature—power, power density, and efficient power—are redefined in terms of the work criteria function (WCF, a concept introduced in this study. The formulation enabled the suggestion and analysis of a unique criterion—the efficient power density (which accounts for the efficiency and power density. Practically speaking, the efficient power and the efficient power density could be defined on any order based on the WCF. The applicability of the WCF is illustrated for the Newtonian heat transfer law (n=1 and for the radiative law (n=4. The importance of WCF is twofold: it gives an explicit design and educational tool to analyze and to display graphically the different criteria side by side and thus helps in design process. Finally, the criteria were compared and some conclusions were drawn.

  4. Synergetcs - a field beyond irreversible thermodynamics

    International Nuclear Information System (INIS)

    This lecture introduces the reader to synergetics, a very young field of interdisciplinary research, which is devoted to the question of self-organization and, quite generally, to the birth of new qualities. After comparing the role of thermodynamics, irreversible thermodynamics and synergetics in the description of phenomena we give a few examples for self-oragnizing systems. Next we outline the mathematical approach and consider the generalized Ginzburg-Landau equations for non equilibrium phase transitions. We continue by applying these equations to the problem of morphogenesis in biology. We close our lecture by extending the formalism to spatially inhomogeneous or oscillating systems and arrive at order-parameter equations which are capable of describing new large classes of higher bifurcation schemes. (HJ)

  5. Entropy, Extropy and the Physical Driver of Irreversibility

    Directory of Open Access Journals (Sweden)

    Attila Grandpierre

    2012-06-01

    Full Text Available We point out that the fundamental irreversibility of Nature requires the introduction of a suitable measure for the distance from equilibrium. We show that entropy, which is widely held to be such a measure, suffers from the problem that it does not have a physical meaning, since it is introduced on the basis of mathematical arguments. As a consequence, the basic physics beyond irreversibility has remained obscure. We present here a simple but transparent physical approach for solving the problem of irreversibility. This approach shows that extropy, the fundamental thermodynamic variable introduced by Katalin Martinás, is the suitable measure for the distance from equilibrium, since it corresponds to the actual driver of irreversible processes. Since extropy explicitly contains in its definition all the general thermodynamic forces that drive irreversible processes, extropy is the suitable physical measure of irreversibility.

  6. Performance of an irreversible quantum Carnot engine with spin 12.

    Science.gov (United States)

    Wu, Feng; Chen, Lingen; Wu, Shuang; Sun, Fengrui; Wu, Chih

    2006-06-01

    The purpose of this paper is to investigate the effect of quantum properties of the working medium on the performance of an irreversible Carnot cycle with spin 12. The optimal relationship between the dimensionless power output P* versus the efficiency eta for the irreversible quantum Carnot engine with heat leakage and other irreversible losses is derived. Especially, the performances of the engine at low temperature limit and at high temperature limit are discussed.

  7. Irreversible magnetic processes under biaxial and uniaxial magnetic anisotropies

    Science.gov (United States)

    Pokharel, S.; Akioya, O.; Alqhtany, N. H.; Dickens, C.; Morgan, W.; Wuttig, M.; Lisfi, A.

    2016-05-01

    Irreversible magnetic processes have been investigated in magnetic systems with two different anisotropy symmetries (uniaxial and biaxial) through angular measurement of the switching field, the irreversible susceptibility and the magnetic viscosity. These two systems consist of two-dimensional cobalt ferrite hetero-structures epitaxially grown on (100) and (110) MgO substrate. It is found that for uniaxial anisotropy the irreversible characteristics of the magnetization are large and display a strong angular dependence, which exhibits its maximum at the easy axis and drops quickly to vanish at the hard axis. However, for biaxial anisotropy the magnetization irreversible characteristics are considerably reduced and are less sensitive to the field angle.

  8. CD19 CAR-targeted T cells induce long-term remission and B Cell Aplasia in an immunocompetent mouse model of B cell acute lymphoblastic leukemia.

    Directory of Open Access Journals (Sweden)

    Marco L Davila

    Full Text Available Although many adults with B cell acute lymphoblastic leukemia (B-ALL are induced into remission, most will relapse, underscoring the dire need for novel therapies for this disease. We developed murine CD19-specific chimeric antigen receptors (CARs and an immunocompetent mouse model of B-ALL that recapitulates the disease at genetic, cellular, and pathologic levels. Mouse T cells transduced with an all-murine CD3ζ/CD28-based CAR that is equivalent to the one being used in our clinical trials, eradicate B-ALL in mice and mediate long-term B cell aplasias. In this model, we find that increasing conditioning chemotherapy increases tumor eradication, B cell aplasia, and CAR-modified T cell persistence. Quantification of recipient B lineage cells allowed us to estimate an in vivo effector to endogenous target ratio for B cell aplasia maintenance. In mice exhibiting a dramatic B cell reduction we identified a small population of progenitor B cells in the bone marrow that may serve as a reservoir for long-term CAR-modified T cell stimulation. Lastly, we determine that infusion of CD8+ CAR-modified T cells alone is sufficient to maintain long-term B cell eradication. The mouse model we report here should prove valuable for investigating CAR-based and other therapies for adult B-ALL.

  9. Irreversible properties of YBCO coated conductors

    CERN Document Server

    Vostner, A

    2001-01-01

    dependence of the irreversibility fields up to 6 T. To gain more insight into the defect structure of the films, neutron irradiation studies were performed on some samples. The introduction of these artificial pinning centers causes large enhancements of the magnetic J sub c in LPE specimens for the field parallel to the c-axis (H//c) at higher temperatures and magnetic fields. The granular structure of the samples does not change up to the highest neutron fluences. However, the enhancements of the transport J sub c 's are not as pronounced as observed in the magnetic measurements. The optimum defect cascade density is determined by sequential irradiation. Especially at higher fluences, the damage caused by the irradiation dominates over the additional pinning force and results in a reduction of the transport J sub c 's. This effect is even more pronounced for fields perpendicular to the c-axis (H//ab). A comparison of irradiation studies between samples deposited by LPE and by PLD shows that LPE films have a...

  10. Irreversible energy flow in forced Vlasov dynamics

    KAUST Repository

    Plunk, Gabriel G.

    2014-10-01

    © EDP Sciences, Società Italiana di Fisica, Springer-Verlag. The recent paper of Plunk [G.G. Plunk, Phys. Plasmas 20, 032304 (2013)] considered the forced linear Vlasov equation as a model for the quasi-steady state of a single stable plasma wavenumber interacting with a bath of turbulent fluctuations. This approach gives some insight into possible energy flows without solving for nonlinear dynamics. The central result of the present work is that the forced linear Vlasov equation exhibits asymptotically zero (irreversible) dissipation to all orders under a detuning of the forcing frequency and the characteristic frequency associated with particle streaming. We first prove this by direct calculation, tracking energy flow in terms of certain exact conservation laws of the linear (collisionless) Vlasov equation. Then we analyze the steady-state solutions in detail using a weakly collisional Hermite-moment formulation, and compare with numerical solution. This leads to a detailed description of the Hermite energy spectrum, and a proof of no dissipation at all orders, complementing the collisionless Vlasov result.

  11. Order and disorder in irreversible decay processes.

    Science.gov (United States)

    Nichols, Jonathan W; Flynn, Shane W; Green, Jason R

    2015-02-14

    Dynamical disorder motivates fluctuating rate coefficients in phenomenological, mass-action rate equations. The reaction order in these rate equations is the fixed exponent controlling the dependence of the rate on the number of species. Here, we clarify the relationship between these notions of (dis)order in irreversible decay, n A → B, n = 1, 2, 3, …, by extending a theoretical measure of fluctuations in the rate coefficient. The measure, Jn-Ln (2)≥0, is the magnitude of the inequality between Jn, the time-integrated square of the rate coefficient multiplied by the time interval of interest, and Ln (2), the square of the time-integrated rate coefficient. Applying the inequality to empirical models for non-exponential relaxation, we demonstrate that it quantifies the cumulative deviation in a rate coefficient from a constant, and so the degree of dynamical disorder. The equality is a bound satisfied by traditional kinetics where a single rate constant is sufficient. For these models, we show how increasing the reaction order can increase or decrease dynamical disorder and how, in either case, the inequality Jn-Ln (2)≥0 can indicate the ability to deduce the reaction order in dynamically disordered kinetics.

  12. Irreversible Electroporation for Colorectal Liver Metastases.

    Science.gov (United States)

    Scheffer, Hester J; Melenhorst, Marleen C A M; Echenique, Ana M; Nielsen, Karin; van Tilborg, Aukje A J M; van den Bos, Willemien; Vroomen, Laurien G P H; van den Tol, Petrousjka M P; Meijerink, Martijn R

    2015-09-01

    Image-guided tumor ablation techniques have significantly broadened the treatment possibilities for primary and secondary hepatic malignancies. A new ablation technique, irreversible electroporation (IRE), was recently added to the treatment armamentarium. As opposed to thermal ablation, cell death with IRE is primarily induced using electrical energy: electrical pulses disrupt the cellular membrane integrity, resulting in cell death while sparing the extracellular matrix of sensitive structures such as the bile ducts, blood vessels, and bowel wall. The preservation of these structures makes IRE attractive for colorectal liver metastases (CRLM) that are unsuitable for resection and thermal ablation owing to their anatomical location. This review discusses different technical and practical issues of IRE for CRLM: the indications, patient preparations, procedural steps, and different "tricks of the trade" used to improve safety and efficacy of IRE. Imaging characteristics and early efficacy results are presented. Much is still unknown about the exact mechanism of cell death and about factors playing a crucial role in the extent of cell death. At this time, IRE for CRLM should only be reserved for small tumors that are truly unsuitable for resection or thermal ablation because of abutment of the portal triad or the venous pedicles.

  13. Clinical importance of digitized chest X-ray for detection of pulmonary infiltrations in bone marrow transplant patients during aplasia

    International Nuclear Information System (INIS)

    Purpose: Evaluation of digitized chest X-ray for the detection of pulmonary infiltrations in bone marrow transplant patients during aplasia. Methods: Digitized chest X-rays of 40 patients (21 female, 19 male) with 'Fever of unknown origin' (FUO) were evaluated concerning radiological signs of pulmonary infiltrations and correlated to clinical findings, blood chemistry, microbiology and bronchoscopy. Additionally, an individual risk profile was established. Results: In 11/40 patients pulmonary infiltrations were detected in digitized chest X-rays (group 1). 10/11 developed an infectious pulmonary infiltration. 29/40 patients developed no pulmonary infiltration (group 2). When fever increased for the first time (initial chest X-ray) a sensitivity, specificity, positive and negative predictive value of 46%, 86%, 56%, 81% and for the chest X-rays in process of 61%, 79%, 68% and 73% was found. C-reactive protein and temperature increase occured statistically significantly earlier (p<0.05) in group 1 compared to group 2. The average latency of digital chest X-rays in comparison to c-reactive protein and temperature increase was 6 days. The incidence of risk factors was significantly higher in group 1 in comparison to group 2 (p<0.05). Conclusion: Digitized chest X-rays are not a reliable method for primary detection of pulmonary infiltrations after bone marrow transplantation. Individual risk factors have to be taken into consideration to indicate further diagnostic methods such as computed tomography at an earlier time. (orig.)

  14. Irreversible Sorption of Contaminants During Ferrihydrite Transformation

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, H.L.; Arthur, S.E.; Brady, P.V.; Cygan, R.T.; Nagy, K.L.; Westrich, H.R.

    1999-05-19

    A better understanding of the fraction of contaminants irreversibly sorbed by minerals is necessary to effectively quantify bioavailability. Ferrihydrite, a poorly crystalline iron oxide, is a natural sink for sorbed contaminants. Contaminants may be sorbed/occluded as ferrihydrite precipitates in natural waters or as it ages and transforms to more crystalline iron oxides such as goethite or hematite. Laboratory studies indicate that Cd, Co, Cr, Cu, Ni, Np, Pb, Sr, U, and Zn are irreversibly sorbed to some extent during the aging and transformation of synthetic ferrihydrite. Barium, Ra and Sr are known to sorb on ferrihydrite in the pH range of 6 to 10 and sorb more strongly at pH values above its zero point of charge (pH> 8). We will review recent literature on metal retardation, including our laboratory and modeling investigation of Ba (as an analogue for Ra) and Sr adsorption/resorption, during ferrihydrite transformation to more crystalline iron oxides. Four ferrihydrite suspensions were aged at pH 12 and 50 °C with or without Ba in 0.01 M KN03 for 68 h or in 0.17 M KN03 for 3424 h. Two ferrihydrite suspensions were aged with and without Sr at pH 8 in 0.1 M KN03 at 70°C. Barium or Sr sorption, or resorption, was measured by periodically centrifuging suspension subsamples, filtering, and analyzing the filtrate for Ba or Sr. Solid subsamples were extracted with 0.2 M ammonium oxalate (pH 3 in the dark) and with 6 M HCl to determine the Fe and Ba or Sr attributed to ferrihydrite (or adsorbed on the goethite/hematite stiace) and the total Fe and Ba or Sr content, respectively. Barium or Sr occluded in goethite/hematite was determined by the difference between the total Ba or Sr and the oxalate extractable Ba or Sr. The percent transformation of ferrihydrite to goethite/hematite was estimated from the ratio of oxalate and HC1 extractable Fe. All Ba was retained in the precipitates for at least 20 h. Resorption of Ba reached a maximum of 7 to 8% of the Ba2+ added

  15. Infecção por Chryseobacterium indologenes: relato de um caso Chryseobacterium indologenes infection: a case report

    OpenAIRE

    Renata de Souza Ferreira; Fabiana Ferreira Barbosa Brandão; Suzana Margareth Lobo

    2010-01-01

    Relatamos um caso de infecção por Chryseobacterium indologenes, presente na cultura de aspirado traqueal em paciente sob ventilação mecânica invasiva, revisando os aspectos epidemiológicos, microbiológicos e o tratamento na unidade de terapia intensiva. Paciente do sexo masculino, 30 anos, internado com quadro de aplasia de medula idiopática e neutropenia febril foi transferido para a unidade de terapia intensiva com quadro de broncopneumonia e sepse grave de origem pulmonar. A maioria dos ca...

  16. An update on irreversible electroporation of liver tumours.

    Science.gov (United States)

    Yeung, Enoch S L; Chung, Max W Y; Wong, Keedon; Wong, Clement Y K; So, Enoch C T; Chan, Albert C Y

    2014-08-01

    OBJECTIVE. To investigate the clinical efficacy and safety of irreversible electroporation for ablation of liver tumour in humans. DATA SOURCES. The PubMed and MEDLINE databases were systematically searched. STUDY SELECTION. Clinical research published in English in the last 10 years until October 2013 that address clinical issues related to irreversible electroporation of human liver tumours were selected. "Liver tumor", "local ablative therapy", and "irreversible electroporation" were used as the search terms. DATA EXTRACTION AND SYNTHESIS. The data extracted for this review was analysed by the authors, with a focus on the clinical efficacy and the safety of irreversible electroporation. The complete response rates look promising, ranging from 72% to 100%, except in one study in a subgroup of liver tumours in which the complete response rate was only 50% that was likely due to the inclusion of larger-size tumours. In one study, the local recurrence rate at 12 months was approximately 40%. As for the safety of irreversible electroporation, there were only a few reported complications (cardiac arrhythmia, pneumothorax, and electrolyte disturbance) that were mostly transient and not serious. There was no reported mortality related to the use of irreversible electroporation. CONCLUSION. Irreversible electroporation is a potentially effective liver tumour ablative therapy that gives rise to only mild and transient side-effects. Further studies with better patient selection criteria and longer follow-up are needed to clarify its role as a first-line liver tumour treatment modality.

  17. Irreversibility of financial time series: A graph-theoretical approach

    Science.gov (United States)

    Flanagan, Ryan; Lacasa, Lucas

    2016-04-01

    The relation between time series irreversibility and entropy production has been recently investigated in thermodynamic systems operating away from equilibrium. In this work we explore this concept in the context of financial time series. We make use of visibility algorithms to quantify, in graph-theoretical terms, time irreversibility of 35 financial indices evolving over the period 1998-2012. We show that this metric is complementary to standard measures based on volatility and exploit it to both classify periods of financial stress and to rank companies accordingly. We then validate this approach by finding that a projection in principal components space of financial years, based on time irreversibility features, clusters together periods of financial stress from stable periods. Relations between irreversibility, efficiency and predictability are briefly discussed.

  18. Investment Irreversibility and Precautionary Savings in General Equilibrium

    DEFF Research Database (Denmark)

    Ejarque, João

    if the shocks affect the marginal efficiency of investment. For all types of shocks, when concavity of the utility function is moderate or high, the irreversibility constraint never binds and the increase in variance has a negligible impact. Persistence in the shock process induces precautionary savings rather......Partial equilibrium models suggest that when uncertainty increases, agents increase savings and at the same time reduce investment in irreversible goods. This paper characterizes this problem in general equilibrium with technology shocks, additive output shocks and shocks to the marginal efficiency...... of investment. Uncertainty is associated with the variance of these random variables, and irreversibility is introduced by a non negativity constraint on investment. I find that irreversibility and changes in uncertainty can be responsible for sizeable movements in aggregate consumption and investment only...

  19. Ecolosical optimization of an irreversible harmonic oscillators Carnot heat engine

    Institute of Scientific and Technical Information of China (English)

    LIU XiaoWei; CHEN LinGen; WU Feng; SUN FengRui

    2009-01-01

    A model of an irreversible quantum Carnot heat engine with heat resistance, internal irreversibility and heat leakage and many non-interacting harmonic oscillators is established in this paper. Based on the quantum master equation and semi-group approach, equations of some important performance parameters, such as power output, efficiency, exergy loss rate and ecological function for the irreversible quantum Carnot heat engine are derived. The optimal ecological performance of the heat engine in the classical limit is analyzed with numerical examples. Effects of internal irreversibility and heat leakage on the ecological performance are discussed. A performance comparison of the quantum heat engine under maximum ecological function and maximum power conditions is also performed.

  20. Ecological optimization of an irreversible harmonic oscillators Carnot heat engine

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A model of an irreversible quantum Carnot heat engine with heat resistance,internal irreversibility and heat leakage and many non-interacting harmonic oscillators is established in this paper. Based on the quantum master equation and semi-group approach,equations of some important performance parameters,such as power output,efficiency,exergy loss rate and ecological function for the irreversible quantum Carnot heat engine are derived. The optimal ecological performance of the heat engine in the classical limit is analyzed with numerical examples. Effects of internal irreversibility and heat leakage on the ecological performance are discussed. A performance comparison of the quantum heat engine under maximum ecological function and maximum power conditions is also performed.

  1. Microscopic reversibility and macroscopic irreversibility: A lattice gas model

    Science.gov (United States)

    Pérez-Cárdenas, Fernando C.; Resca, Lorenzo; Pegg, Ian L.

    2016-09-01

    We present coarse-grained descriptions and computations of the time evolution of a lattice gas system of indistinguishable particles, whose microscopic laws of motion are exactly reversible, in order to investigate how or what kind of macroscopically irreversible behavior may eventually arise. With increasing coarse-graining and number of particles, relative fluctuations of entropy rapidly decrease and apparently irreversible behavior unfolds. Although that behavior becomes typical in those limits and within a certain range, it is never absolutely irreversible for any individual system with specific initial conditions. Irreversible behavior may arise in various ways. We illustrate one possibility by replacing detailed integer occupation numbers at lattice sites with particle probability densities that evolve diffusively.

  2. Kinetic theory of nonequilibrium ensembles, irreversible thermodynamics, and generalized hydrodynamics

    CERN Document Server

    Eu, Byung Chan

    2016-01-01

    This book presents the fundamentals of irreversible thermodynamics for nonlinear transport processes in gases and liquids, as well as for generalized hydrodynamics extending the classical hydrodynamics of Navier, Stokes, Fourier, and Fick. Together with its companion volume on relativistic theories, it provides a comprehensive picture of the kinetic theory formulated from the viewpoint of nonequilibrium ensembles in both nonrelativistic and, in Vol. 2, relativistic contexts. Theories of macroscopic irreversible processes must strictly conform to the thermodynamic laws at every step and in all approximations that enter their derivation from the mechanical principles. Upholding this as the inviolable tenet, the author develops theories of irreversible transport processes in fluids (gases or liquids) on the basis of irreversible kinetic equations satisfying the H theorem. They apply regardless of whether the processes are near to or far removed from equilibrium, or whether they are linear or nonlinear with respe...

  3. Irreversible electroporation of lung neoplasm: A case series

    OpenAIRE

    Usman, Mumal; Moore, William; Talati, Ronak; Watkins, Kevin; Bilfinger, Thomas V.

    2012-01-01

    Summary Background Percutaneous irreversible electroporation (IRE) of lung tumors is a new minimally invasive technique which has recently been used in the treatment of soft tissue tumors. Case Reports The case histories are presented of two patients with unresectable malignancies in the lung, who underwent irreversible electroporation as a treatment attempt. The procedure was performed under CT guidance and was uneventful. Conclusions At follow up 6 months later, the tumors both appeared to ...

  4. Mandatory Unbundling and Irreversible Investment in Telecom Networks

    OpenAIRE

    Robert S. Pindyck

    2004-01-01

    This paper addresses the impact on investment incentives of the network sharing arrangements mandated by the Telecommunications Act of 1996, with a focus on the implications of irreversible investment. Although the goal is to promote competition, the sharing rules now in place reduce incentives to build new networks or upgrade existing ones. Such investments are irreversible -- they involve sunk costs. The basic framework adopted by regulators allows entrants to utilize such facilities at pri...

  5. Towards irreversibility with a finite bath of oscillators

    International Nuclear Information System (INIS)

    We investigate the routes by which a bath composed of a finite number of oscillators at zero temperature approaches the induction of dissipation when it nears the usual limit of dense spectrum spread in an infinite interval. It is shown that, when this limit is taken, different distributions of environment frequencies can lead to the same irreversible evolution. However, when we move away from it, the dynamics departs from irreversibility in qualitatively different manners.

  6. por valores

    Directory of Open Access Journals (Sweden)

    Jazmín Díaz-Barrios

    2005-01-01

    Full Text Available La era actual se caracteriza por una búsqueda de la identidad del hombre, donde el pivote del cambio organizacional es el individuo; cambiar en este entorno depende, en gran medida, de los valores que imperen en la cultura de la organización. Este trabajo documental intenta identificar aquellos valores, condición sine-qua-non, para el logro de los objetivos de cambio y analizarlos a fin de determinar sus indicadores, con el objeto de presentar una herramienta a las organizaciones que les facilite adaptarse a los nuevos tiempos. Se encontró que los valores: Delegación, Comunicación, Colaboración, Participación y Aprendizaje, son esenciales en los cambios integrales de esta era. Se determinaron 20 indicadores de su presencia. Se concluye que con esta información cada ente puede elaborar instrumentos que le permitan saber si los valores requeridos están presentes y en caso contrario tomar decisiones que alineen a la organización alrededor de los valores humanistas planteados, incrementando así las posibilidades de éxito en el proceso de cambio y por ende, las posibilidades de supervivencia en esta nueva época.

  7. Improvement in Erythropoieis-stimulating Agent-induced Pure Red-cell Aplasia by Introduction of Darbepoetin-α When the Anti-erythropoietin Antibody Titer Declines Spontaneously

    OpenAIRE

    Lee, Hajeong; Yang, Jaeseok; Kim, Hyosang; Kwon, Ju Won; Oh, Kook-Hwan; Joo, Kwon Wook; Kim, Yon Su; Ahn, Curie; Han, Jin Suk; Kim, Suhnggwon

    2010-01-01

    Anti-erythropoietin antibodies usually cross-react with all kinds of recombinant erythropoietins; therefore, erythropoiesis-stimulating agent (ESA)-induced pure red-cell aplasia (PRCA) is not rescued by different ESAs. Here, we present a case of ESA-induced PRCA in a 36-yr-old woman with chronic kidney disease, whose anemic condition improved following reintroduction of darbepoetin-α. The patient developed progressive, severe anemia after the use of erythropoietin-α. As the anemia did not imp...

  8. Attribution of irreversible loss to anthropogenic climate change

    Science.gov (United States)

    Huggel, Christian; Bresch, David; Hansen, Gerrit; James, Rachel; Mechler, Reinhard; Stone, Dáithí; Wallimann-Helmer, Ivo

    2016-04-01

    The Paris Agreement (2015) under the UNFCCC has anchored loss and damage in a separate article which specifies that understanding and support should be enhanced in areas addressing loss and damage such as early warning, preparedness, insurance and resilience. Irreversible loss is a special category under loss and damage but there is still missing clarity over what irreversible loss actually includes. Many negative impacts of climate change may be handled or mitigated by existing risk management, reduction and absorption approaches. Irreversible loss, however, is thought to be insufficiently addressed by risk management. Therefore, countries potentially or actually affected by irreversible loss are calling for other measures such as compensation, which however is highly contested in international climate policy. In Paris (2015) a decision was adopted that loss and damage as defined in the respective article of the agreement does not involve compensation and liability. Nevertheless, it is likely that some sort of mechanism will eventually need to come into play for irreversible loss due to anthropogenic climate change, which might involve compensation, other forms of non-monetary reparation, or transformation. Furthermore, climate litigation has increasingly been attempted to address negative effects of climate change. In this context, attribution is important to understand the drivers of change, what counts as irreversible loss due to climate change, and, possibly, who or what is responsible. Here we approach this issue by applying a detection and attribution perspective on irreversible loss. We first analyze detected climate change impacts as assessed in the IPCC Fifth Assessment Report. We distinguish between irreversible loss in physical, biological and human systems, and accordingly identify the following candidates of irreversible loss in these systems: loss of glaciers and ice sheets, loss of subsurface ice (permafrost) and related loss of lake systems; loss

  9. Partially-irreversible sorption of formaldehyde in five polymers

    Science.gov (United States)

    Ye, Wei; Cox, Steven S.; Zhao, Xiaomin; Frazier, Charles E.; Little, John C.

    2014-12-01

    Due to its environmental ubiquity and concern over its potential toxicity, the mass-transfer characteristics of formaldehyde are of critical importance to indoor air quality research. Previous studies have suggested that formaldehyde mass transfer in polymer is partially irreversible. In this study, mechanisms that could cause the observed irreversibility were investigated. Polycarbonate and four other polymeric matrices were selected and subjected to formaldehyde sorption/desorption cycles. Mass transfer of formaldehyde was partially irreversible in all cases, and three potential mechanisms were evaluated. First, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis was used to investigate possible formaldehyde polymerization on polymer surfaces. ATR-FTIR showed no detectable paraformaldehyde or formaldehyde on the film surfaces that had been exposed to formaldehyde and air. ATR-FTIR did detect aliphatic acids suggesting oxidation had occurred on film surfaces as a result of exposure to formaldehyde. However, additional study suggested that air is not the primary cause for irreversibility. Second, statistical physics theory was tested as a possible explanation. According to this theory, reversible and irreversible sorption could be taking place simultaneously. The irreversible fraction should be constant during sorption and the fraction could be determined by performing a complete sorption/desorption test. The sorption/desorption data was consistent with this theory. Third, chemisorption was considered as another possible cause for irreversibility. Extraction/fluorimetry testing of post-sorption and post-desorption polymer films showed measurable quantities of formaldehyde suggesting that some of the chemisorbed formaldehyde was reversible at the higher extraction temperature. Further quantitative study on chemical reaction products is needed.

  10. Infecção por Chryseobacterium indologenes: relato de um caso Chryseobacterium indologenes infection: a case report

    Directory of Open Access Journals (Sweden)

    Renata de Souza Ferreira

    2010-03-01

    Full Text Available Relatamos um caso de infecção por Chryseobacterium indologenes, presente na cultura de aspirado traqueal em paciente sob ventilação mecânica invasiva, revisando os aspectos epidemiológicos, microbiológicos e o tratamento na unidade de terapia intensiva. Paciente do sexo masculino, 30 anos, internado com quadro de aplasia de medula idiopática e neutropenia febril foi transferido para a unidade de terapia intensiva com quadro de broncopneumonia e sepse grave de origem pulmonar. A maioria dos casos já relatados de pacientes com infecção por Chryseobacterium indologenes apresentavam patologias graves associadas e infecções polimicrobianas que podem dificultar a interpretação da efetividade da terapia antimicrobiana contra este agente.A case of Chryseobacterium indologenes infection is reported, identified in an invasive mechanic ventilation patient's tracheal aspiration material. Epidemiological, microbiological, and intensive care unit therapy aspects are discussed. The patient was a 30 years-old male, admitted with idiopathic medullary aplasia and febrile neutropenia, referred to the intensive care unit with severe bronchopneumonia and sepsis of pulmonary origin. Most of the previously reported Chryseobacterium indologenes infection cases were associated with severe diseases and polymicrobial infections which could make difficult interpreting antimicrobial therapy options against this agent.

  11. Equilibrium, fluctuation relations and transport for irreversible deterministic dynamics

    CERN Document Server

    Colangeli, Matteo

    2011-01-01

    In a recent paper [M. Colangeli \\textit{et al.}, J.\\ Stat.\\ Mech.\\ P04021, (2011)] it was argued that the Fluctuation Relation for the phase space contraction rate $\\Lambda$ could suitably be extended to non-reversible dissipative systems. We strengthen here those arguments, providing analytical and numerical evidence based on the properties of a simple irreversible nonequilibrium baker model. We also consider the problem of response, showing that the transport coefficients are not affected by the irreversibility of the microscopic dynamics. In addition, we prove that a form of \\textit{detailed balance}, hence of equilibrium, holds in the space of relevant variables, despite the irreversibility of the phase space dynamics. This corroborates the idea that the same stochastic description, which arises from a projection onto a subspace of relevant coordinates, is compatible with quite different underlying deterministic dynamics. In other words, the details of the microscopic dynamics are largely irrelevant, for ...

  12. Irreversibility of the two-dimensional enstrophy cascade

    CERN Document Server

    Piretto,; Boffetta, G

    2016-01-01

    We study the time irreversibility of the direct cascade in two-dimensional turbulence by looking at the time derivative of the square vorticity along Lagrangian trajectories, a quantity which we call metenstrophy. By means of extensive numerical simulations we measure the time irreversibility from the asymmetry of the PDF of the metenstrophy and we find that it increases with the Reynolds number of the cascade, similarly to what found in three-dimensional turbulence. A detailed analysis of the different contributions to the enstrophy budget reveals a remarkable difference with respect to what observed for the direct cascade, in particular the role of the statistics of the forcing to determine the degree of irreversibility.

  13. Irreversibilidad y pluralismo ontológico Irreversibility and ontological pluralism

    Directory of Open Access Journals (Sweden)

    Martín Labarca

    2007-06-01

    Full Text Available El problema de la irreversibilidad encuentra su origen a fines del siglo xix y comienzos del siglo xx con los trabajos de Maxwell, Boltzmann y Gibbs. La controversia surge al intentar compatibilizar la evolución macroscópica irreversible de los sistemas termodinámicos con la dinámica t-invariante de sus constituyentes microscópicos. En la formulación tradicional de la mecánica estadística, la evolución irreversible se explica mediante la introducción de un grano grueso sobre la dinámica microscópica subyacente. Por este motivo, suele considerarse que la mecánica estadística sólo brinda una descripción subjetiva o meramente gnoseológica de la irreversibilidad. El propósito del presente trabajo consiste en impugnar las interpretaciones tradicionales de la irreversibilidad, poniendo de manifiesto que su único fundamento es la implícita adopción de un realismo metafísico que adjudica prioridad ontológica al mundo microscópico. Argumentaremos que las dificultades se disuelven cuando el problema es abordado sobre la base de un pluralismo ontológico de raíces kantianas, inspirado en el realismo internalista de Putnam. Desde esta perspectiva filosófica, la irreversibilidad macroscópica es una propiedad objetiva que no necesita ser explicada en términos microscópicos para adquirir legitimidad ontológica: el grano grueso que vincula ambas evoluciones no es más que la relación entre dos descripciones igualmente objetivas.The problem of irreversibility finds its roots at the end of 19th century and the beginning of 20th century with the works of Maxwell, Boltzmann and Gibbs. The controversy arises when trying to make compatible the irreversible macroscopic evolution of thermodynamics systems with t-invariant dynamics of its microscopic components. In the traditional approach of statistical mechanics, the irreversible evolution is explained by introducing a coarse grain on the underlying microscopic dynamics. For this reason

  14. Hydraulically irreversible fouling on ceramic MF/UF membranes: comparison of fouling indices, foulant composition and irreversible pore narrowing

    KAUST Repository

    Shang, Ran

    2015-05-06

    The application of ceramic membranes in water treatment is becoming increasing attractive because of their long life time and excellent chemical, mechanical and thermal stability. However, fouling of ceramic membranes, especially hydraulically irreversible fouling, is still a critical aspect affecting the operational cost and energy consumption in water treatment plants. In this study, four ceramic membranes with pore sizes or molecular weight cut-off (MWCO) of 0.20 μm, 0.14 μm, 300 kDa and 50 kDa were compared during natural surface water filtration with respect to hydraulically irreversible fouling index (HIFI), foulant composition and narrowing of pore size due to the irreversible fouling. Our results showed that the hydraulically irreversible fouling index (HIFI) was proportional to the membrane pore size (r2=0.89) when the same feed water was filtrated. The UF membranes showed lower HIFI values than the MF membranes. Pore narrowing (internal fouling) was found to be a main fouling pattern of the hydraulically irreversible fouling. The internal fouling was caused by monolayer adsorption of foulants with different sizes that is dependent on the size of the membrane pore.

  15. New experimental approach to treatment of radiation-induced bone marrow aplasia: ex vivo expansion of hematopoietic cells; Nouvelle approche experimentale du traitement de l`aplasie medullaire radio-induite

    Energy Technology Data Exchange (ETDEWEB)

    Herodin, F.; Mathieu, J.; Drouet, M.; Grenier, N.; Grange, L.; Bourin, P.; Vetillard, J.; Thierry, D.; Mestries, J.C.

    1995-12-31

    The management of bone marrow aplasia secondary to accidental exposure to high doses of ionizing radiations requires new therapeutic protocols in addition to cytokine therapy. The in vitro incubation of hematopoietic stem and progenitor cells from irradiated nonhuman primates with negative and positive regulators of hematopoiesis may lead to helpful products of transfusion. (author).

  16. When an Adiabatic Irreversible Expansion or Compression Becomes Reversible

    Science.gov (United States)

    Anacleto, Joaquim; Ferreira, J. M.; Soares, A. A.

    2009-01-01

    This paper aims to contribute to a better understanding of the concepts of a "reversible process" and "entropy". For this purpose, an adiabatic irreversible expansion or compression is analysed, by considering that an ideal gas is expanded (compressed), from an initial pressure P[subscript i] to a final pressure P[subscript f], by being placed in…

  17. Intrinsic Decoherence and Irreversibility in the Quasiperiodic Kicked Rotor

    CERN Document Server

    Shifino, A C S; Siri, R; Romanelli, A; Donangelo, R J

    2003-01-01

    We show that some classically chaotic quantum systems uncoupled from noisy environments may generate intrinsic decoherence with all its associated effects. In particular, we have observed time irreversibility and high sensitivity to small perturbations in the initial conditions in a quasiperiodic version of the kicked rotor. The existence of simple quantum systems with intrinsic decoherence clarifies the quantum--classical correspondence in chaotic systems.

  18. Irreversible Encephalopathy After Treatment With High-Dose Intravenous Metronidazole

    NARCIS (Netherlands)

    Groothoff, Miriam V. R.; Hofmeijer, Jannette; Sikma, Maaike A.; Meulenbelt, Jan

    2010-01-01

    Background: Encephalopathy associated with metronidazole is rare and, in most cases, reversible following discontinuation. Objective: We describe a case of fatal encephalopathy after treatment with high-dose intravenous metronidazole and the potential causes of the irreversibility. Case summary: A 3

  19. Analysis of irreversible displacements of Daniel-Johnson dam

    Energy Technology Data Exchange (ETDEWEB)

    Chouinard, L.; Zhao, W. [McGill Univ., Montreal, PQ (Canada); Lariviere, R. [Hydro-Quebec, Montreal, PQ (Canada); Cote, P. [Hydro-Quebec Production, Baie-Comeau, PQ (Canada)

    2006-07-01

    Irreversible displacements in dams are associated with alkali-aggregate reaction, creep, and other damaging effects that compromise the safety of dams. An identification of the nature of irreversible displacements is needed to predict the future behaviour of dams as well as to select appropriate remedial measures. This paper provided details of a principal component analysis (PCA) used to investigate swelling and small irreversible displacements observed at the Daniel-Johnson dam in Quebec. PCA is a multivariate statistical method that performs the analysis of correlations or covariances between several random variables simultaneously. Three datasets were used: (1) reservoir water level; (2) air temperature; and (3) pendulum displacements. Standard linear regression analyses (HST) were performed for each variable in order to eliminate outliers and replace missing values. The multivariate dataset was then used to perform PCA on the entire dataset as well as on subsets from the original data. Displacement data from pendulums were used in the multivariate statistical analysis in which each component was treated as a separate variable. The comparison of irreversible displacements of the dam from HST analysis and principal component analysis (PCA) indicated that results were consistent with the data. The PCA analysis identified dominant patterns of behaviour and detected 2 distinct components of irreversible deformations arising from creep and swelling of concrete. Results of the study showed that the PCA analysis led to a better understanding of the overall behaviour of the dam and of individual arches and buttresses. It was concluded that the PCA analysis method will help to improve dam safety in addition to more accurately predicting the future behaviour of dams. 6 refs., 2 tabs., 9 figs.

  20. Preparation of irreversible hydrocolloids to improve retention of complete dentures

    Directory of Open Access Journals (Sweden)

    Aleksov Ljiljana

    2008-01-01

    Full Text Available Introduction Precise reproduction of anatomical-morphological details of dentures support on working models presupposes adequate application of modern impression materials and casting procedure, as well as minimal dimensional change of these materials. The aim of the study: experimental and clinical research is connected to irreversible hydrocolloids and the objective was to examine the most suitable consistency of the alginate as the impression mass for the purpose of improving retention of complete dentures. Material and methods This research included 35 completely toothless patients, most of who had already had complete dentures, 40-80 years of age and of both sexes. Static adhesion was measured with aery late plates made of adequate corresponding and various models depending on consistency of the irreversible hydrocolloids. Each model was cut into three parts, the cuts obtained were mutually compared, and computerized graphic charts of each section were made. Results The results of the research show that there is a greater retention force in the acrylate plates obtained on models castled on an anatomical impression base taken with irreversible hydrocolloides of solid consistency. Analysis of the results shows such quality of impressed tissues that they are practically slightly displaced by the impressions regardless of the consistency of the material impressed. Conclusion In conclusion it is pointed out that the preparation of irreversible hydrocolloides must be carried out by strictly obeying the powder-water weight ratios. The sections of the models obtained by irreversible hydrocolloides of various consistencies, that is by applying different pressures, point to minimal displacement of tissues and great differences in the retention force in favor of the compressive impression.

  1. BNNT-mediated irreversible electroporatio: its potential on cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Vittoria Raffa, Cristina Riggio, Michael W. Smith, Kevin C. Jordan, Wei Cao, Alfred Cuschieri

    2012-10-01

    Tissue ablation, i.e., the destruction of undesirable tissues, has become an important minimally invasive technique alternative to resection surgery for the treatment of tumours. Several methods for tissue ablation are based on thermal techniques using cold, e.g. cryosurgery [1] or heat, e.g. radiofrequency [2] or high-intensity focused ultrasound [3] or nanoparticle-mediated irradiation [4]. Alternatively, irreversible electroporation (IRE) has been proposed as non thermal technique for minimally invasive tissue ablation based on the use of electrical pulses. When the electric field is applied to a cell, a change in transmembrane potential is induced, which can cause biochemical and physiological changes of the cell. When the threshold value of the transmembrane potential is exceeded, the cell membrane becomes permeable, thus allowing entrance of molecules that otherwise cannot cross the membrane [5]. A further increase in the electric field intensity may cause irreversible membrane permeabilization and cell death. These pulses create irreversible defects (pores) in the cell membrane lipid bilayer, causing cell death through loss of cell homeostasis [6]. This is desirable in tumour ablation in order to produce large cell death, without the use of cytostatic drugs. A study of Davalos, Mir and Rubinsky showed that IRE can ablate substantial volumes of tissue without inducing a thermal effect and therefore serve as an independent and new tissue ablation modality; this opened the way to the use of IRE in surgery [7]. Their finding was subsequently confirmed in studies on cells [8], small animal models [9] and in large animal models in the liver [10] and the heart [11]. The most important finding in these papers is that irreversible electroporation produces precisely delineated ablation zones with cell scale resolution between ablated and non-ablated areas, without zones in which the extent of damage changes gradually as during thermal ablation. Furthermore, it is

  2. Bone marrow pathology in dogs and cats with non-regenerative immune-mediated haemolytic anaemia and pure red cell aplasia.

    Science.gov (United States)

    Weiss, D J

    2008-01-01

    Many dogs and cats with immune-mediated haemolytic anaemia (IMHA) lack a bone marrow erythroid regenerative response. To better understand the failure of the bone marrow to respond to the anaemia, bone marrow pathology associated with non-regenerative IMHA and pure red cell aplasia (PRCA) was reviewed. Eighty-two affected dogs and 57 affected cats were identified from a population presenting to a referral hospital over a 10-year period. Fifty-five dogs had non-regenerative IMHA (38 had bone marrow erythroid hyperplasia and 17 had erythroid maturation arrest) and 27 had pure red cell aplasia (PRCA). Twenty-eight cats had non-regenerative IMHA (24 had erythroid hyperplasia and 4 had erythroid maturation arrest) and 29 had PRCA. A variety of pathological changes were observed in bone marrow aspirates and core biopsy specimens taken from these animals. These changes included dysmyelopoiesis, myelonecrosis, myelofibrosis, interstitial oedema, haemorrhage, acute inflammation, haemophagocytic syndrome, lymphocyte aggregation, and lymphocyte or plasma cell hyperplasia. In both dogs and cats, dysmyelopoiesis, myelonecrosis, myelofibrosis, interstitial oedema, haemorrhage, acute inflammation and haemophagocytic syndrome were primarily noted in bone marrow specimens where there was evidence of erythroid hyperplasia. These animals were also more often neutropenic and thrombocytopenic, and had decreased 60 day survival when compared with dogs or cats with non-regenerative anaemia associated with erythroid maturation arrest or PRCA. Therefore, the pathogenesis of the non-regenerative anaemia in non-regenerative IMHA may involve both antibody-mediated destruction of bone marrow precursor cells and pathological events within the bone marrow that result in ineffective erythropoiesis.

  3. Analysis of Reversible Simulation of Irreversible Computation by Pebble Games

    CERN Document Server

    Li, Maozhen; Vitanyi, P; Li, Ming; Tromp, John; Vitanyi, Paul

    1998-01-01

    Reversible simulation of irreversible algorithms is analyzed in the stylized form of a `reversible' pebble game. While such simulations incur little overhead in additional computation time, they use a large amount of additional memory space during the computation. The reacheable reversible simulation instantaneous descriptions (pebble configurations) are characterized completely. As a corollary we obtain the reversible simulation by Bennett and that among all simulations that can be modelled by the pebble game, Bennett's simulation is optimal in that it uses the least auxiliary space for the greatest number of simulated steps. One can reduce the auxiliary storage overhead incurred by the reversible simulation at the cost of allowing limited erasing leading to an irreversibility-space tradeoff. We show that in this resource-bounded setting the limited erasing needs to be performed at precise instants during the simulation. We show that the reversible simulation can be modified so that it is applicable also whe...

  4. Irreversible adsorption of phenolic compounds by activated carbons

    International Nuclear Information System (INIS)

    Studies were undertaken to determine the reasons why phenolic sorbates can be difficult to remove and recover from activated carbons. The chemical properties of the sorbate and the adsorbent surface, and the influences of changes in the adsorption and desorption conditions were investigated. Comparison of isotherms established after different contact times or at different temperatures indicated that phenolic compounds react on carbon surfaces. The reaction rate is a strong function of temperature. Regeneration of carbons by leaching with acetone recovered at least as much phenol as did regeneration with other solvents or with displacers. The physiochemical properties of adsorbents influences irreversible uptakes. Sorbates differed markedly in their tendencies to undergo irreversible adsorption. 64 refs., 47 figs., 32 tabs

  5. A unified viscoplasticity constitutive model based on irreversible thermodynamics

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A unified viscoplasticity constitutive model for metal materials is developed within the framework of irreversible thermodynamics, and an expression for the Helmholtz free energy function involving the parameters reflecting kinematic hardening and isotropic hardening is given. At the same time a non-associated flow potential function including the corresponding state variables is also given, from which the flow equation and the evolution equations of the internal state variables are derived. Thus, a general theoretical framework constructing a unified viscoplasticity constitutive model is given. Compared with the typical unified viscoplasticity constitutive models, the presented model evidently satisfies the irreversible thermodynamics laws. Moreover, this method not only provides a new theoretical foundation for further development of the unified viscoplasticity constitutive model, but also gives a new theoretical framework for the stress-strain analysis of more materials.

  6. A unified viscoplasticity constitutive model based on irreversible thermodynamics

    Institute of Scientific and Technical Information of China (English)

    LIU ChangChun; LV HeXiang; GUAN Ping

    2008-01-01

    A unified viscoplasticity constitutive model for metal materials is developed within the framework of irreversible thermodynamics, and an expression for the Helmholtz free energy function involving the parameters reflecting kinematic hardening and isotropic hardening is given. At the same time a non-associated flow potential function including the corresponding state variables is also given, from which the flow equation and the evolution equations of the internal state variables are derived. Thus, a general theoretical framework constructing a unified viscoplasticity con-stitutive model is given. Compared with the typical unified viscoplasticity constitu-tive models, the presented model evidently satisfies the irreversible thermody-namics laws. Moreover, this method not only provides a new theoretical foundation for further development of the unified viscoplasticity constitutive model, but also gives a new theoretical framework for the stress-strain analysis of more materials.

  7. Determination of chlorogenic acid by flow injection irreversible biamperometry

    Institute of Scientific and Technical Information of China (English)

    Li Jun Li; Qi Feng Chen; Lai Bo Yu; Zhao Heng Zhong; Jun Feng; Hao Cheng; Hong Xing Kong; Jian Ling Wu

    2007-01-01

    A flow injection irreversible biamperometric method for the determination of chlorogenic acid is described. The proposed method is based on the electrochemical oxidation of chlorogenic acid at pretreated platinum electrode and the reduction of permanganate at another electrode to form an irreversible biamperometric detection system. Under the external potential difference(△E) of 0 V, in the 0.05 mol/L sulfuric acid, chlorogenic acid can be determined over the range 0.8-120 mg/L with a sample measurement frequency of 80 samples/h. The detection limit is 0.18 mg/L. The proposed method exhibits the satisfactory reproducibility with a relative standard derivation (R.S.D.) of 2.21% for 19 successive determinations of 40 mg/L.

  8. Ecological optimization for an irreversible magnetic Ericsson refrigeration cycle

    International Nuclear Information System (INIS)

    An irreversible Ericsson refrigeration cycle model is established, in which multi-irreversibilities such as finite-rate heat transfer, regenerative loss, heat leakage, and the efficiency of the regenerator are taken into account. Expressions for several important performance parameters, such as the cooling rate, coefficient of performance (COP), power input, exergy output rate, entropy generation rate, and ecological function are derived. The influences of the heat leakage and the time of the regenerative processes on the ecological performance of the refrigerator are analyzed. The optimal regions of the ecological function, cooling rate, and COP are determined and evaluated. Furthermore, some important parameter relations of the refrigerator are revealed and discussed in detail. The results obtained here have general significance and will be helpful in gaining a deep understanding of the magnetic Ericsson refrigeration cycle. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  9. Ecological optimization for an irreversible magnetic Ericsson refrigeration cycle

    Institute of Scientific and Technical Information of China (English)

    Wang Hao; Wu Guo-Xing

    2013-01-01

    An irreversible Ericsson refrigeration cycle model is established,in which multi-irreversibilities such as finite-rate heat transfer,regenerative loss,heat leakage,and the efficiency of the regenerator are taken into account.Expressions for several important performance parameters,such as the cooling rate,coefficient of performance (COP),power input,exergy output rate,entropy generation rate,and ecological function are derived.The influences of the heat leakage and the time of the regenerative processes on the ecological performance of the refrigerator are analyzed.The optimal regions of the ecological function,cooling rate,and COP are determined and evaluated.Furthermore,some important parameter relations of the refrigerator are revealed and discussed in detail.The results obtained here have general significance and will be helpful in gaining a deep understanding of the magnetic Ericsson refrigeration cycle.

  10. Thermodynamic Analysis of the Irreversibilities in Solar Absorption Refrigerators

    Directory of Open Access Journals (Sweden)

    Emma Berrich Betouche

    2016-03-01

    Full Text Available A thermodynamic analysis of the irreversibility on solar absorption refrigerators is presented. Under the hierarchical decomposition and the hypothesis of an endoreversible model, many functional and practical domains are defined. The effect of external heat source temperature on the entropy rate and on the inverse specific cooling load (ISCL multiplied by the total area of the refrigerator A/Qe are studied. This may help a constructor to well dimension the solar machine under an optimal technico-economical criterion A/Qe and with reasonable irreversibility on the refrigerator. The solar concentrator temperature effect on the total exchanged area, on the technico-economical ratio A/Qe, and on the internal entropy rate are illustrated and discussed. The originality of these results is that they allow a conceptual study of a solar absorption refrigeration cycle.

  11. Dynamics of polydisperse irreversible adsorption: a pharmacological example

    CERN Document Server

    Erban, R; Fisher, K D; Kevrekidis, Yu G; Seymour, L W; Chapman, Jonathan; Erban, Radek; Fisher, Kerry D.; Kevrekidis, Ioannis G.; Seymour, Leonard W.

    1999-01-01

    Many drug delivery systems suffer from undesirable interactions with the host immune system. It has been experimentally established that covalent attachment (irreversible adsorption) of suitable macromolecules to the surface of the drug carrier can reduce such undesirable interactions. A fundamental understanding of the adsorption process is still lacking. In this paper, the classical random irreversible adsorption model is generalized to capture certain essential processes involved in pharmacological applications, allowing for macromolecules of different sizes, partial overlapping of the tails of macromolecules, and the influence of reactions with the solvent on the adsorption process. Working in one dimension, an integro-differential evolution equation for the adsorption process is derived and the asymptotic behaviour of the surface area covered and the number of molecules attached to the surface is studied. Finally, equation-free dynamic renormalization tools are applied to study the asymptotically self-si...

  12. Thermodynamic irreversibility and performance characteristics of thermoelectric power generator

    International Nuclear Information System (INIS)

    Thermodynamic irreversibility and performance characteristics of a thermoelectric power generator are investigated. The influence of the external load parameter, the thermal conductivity ratio, the figure of Merit, and the conductance ratio on the efficiency, the output power, and the entropy generation rate is predicted for various device operating parameters. It is found that the device efficiency increases to reach its maximum at the critical value of the output power and operating the device beyond the critical output power lowers the thermal efficiency and enhances the entropy generation rate significantly in the device. - Highlights: • The thermodynamic irreversibility in thermoelectric generator is studied. • Thermodynamic characteristics of thermoelectric device are investigated. • Influence of various parameters on performance is presented. • The device efficiency reaches its maximum at a critical output power. • The entropy generation increases beyond the critical output power

  13. Uncertainty, Irreversibility and the Timing Problems of Environmental Policy

    Institute of Scientific and Technical Information of China (English)

    Yang Haisheng; Jia Jia; Zhou Yongzhang

    2006-01-01

    Most environmental issues and policy designing are uncertain and irreversible; therefore, the timing of environmental policy implementation becomes especially important. This paper establishes a random dynamic programming model and analyzes the optimal timing problems in environmental policy under uncertain variables. This model results indicate that two variables have a significant impact on the timing of environmental policy implementation and they work in opposite direcfons: on one hand, the more uncertain the economy is, the higher the cost of policies implementation will be, and consequently the incentive to immediately adopt the policy will be stronger. On the other hand, the higher the uncertainty of the environment is, the stronger the irreversibility of ecological harm caused by pollutants per unit will be. Therefore, the government should implement new environmental policies as early as possible in order to gain more ecological benefits.

  14. Comparison of reversible and irreversible dipolar assemblies in a ferrofluid

    Energy Technology Data Exchange (ETDEWEB)

    Klokkenburg, M. [Van' t Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute, Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands)]. E-mail: m.klokkenburg@chem.uu.nl; Erne, B.H. [Van' t Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute, Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands)

    2006-11-15

    Zero-field aggregation of magnetic nanoparticles in a ferrofluid can either be irreversible or result from a dynamic equilibrium; the two cases can be distinguished by measurements of the complex magnetic susceptibility and by cryogenic transmission electron microscopy (cryo-TEM). We demonstrate this by comparing two colloidal systems that show dipolar structure formation in zero field. A dispersion of magnetic iron nanoparticles is gradually oxidized to decrease the magnetic moments, and despite the vanishing dipolar attractions, thermal motion does not break up the dipolar structures into single particles. Instead, the dipolar structures become chemically fixed during the oxidation process, an example of irreversible aggregation. In contrast, the zero-field dipolar structures in a chemically stable magnetite dispersion are found to disintegrate upon dilution, indicating that the structures are reversible and result from a dynamic equilibrium.

  15. Irreversible adsorption of phenolic compounds by activated carbons

    Energy Technology Data Exchange (ETDEWEB)

    Grant, T.M.; King, C.J.

    1988-12-01

    Studies were undertaken to determine the reasons why phenolic sorbates can be difficult to remove and recover from activated carbons. The chemical properties of the sorbate and the adsorbent surface, and the influences of changes in the adsorption and desorption conditions were investigated. Comparison of isotherms established after different contact times or at different temperatures indicated that phenolic compounds react on carbon surfaces. The reaction rate is a strong function of temperature. Regeneration of carbons by leaching with acetone recovered at least as much phenol as did regeneration with other solvents or with displacers. The physiochemical properties of adsorbents influences irreversible uptakes. Sorbates differed markedly in their tendencies to undergo irreversible adsorption. 64 refs., 47 figs., 32 tabs.

  16. Determinación irreversible a la floración del aguacate 'Hass' en Michoacán Irreversible determination to flowering for 'Hass' avocado in Michoacán

    Directory of Open Access Journals (Sweden)

    José Luis Rocha-Arroyo

    Full Text Available El objetivo de este estudio, fue precisar los periodos en que ocurre la determinación irreversible a la floración en yemas apicales de brotes vegetativos de los flujos de invierno, primavera y verano en huertos de aguacate con y sin riego establecidos en cuatro condiciones climáticas. El estudio se realizó durante 2006-2008, en seis huertos comerciales de aguacate 'Hass' en el estado de Michoacán, México. En cada huerto se seleccionaron 20 árboles y cada uno se etiquetaron 30 brotes de cada flujo vegetativo. Los tratamientos consistieron en anillado y defoliación de un brote por árbol cada quince días para cada flujo vegetativo. El clima, influyó sobre la fecha en que ocurrió la determinación irreversible a la floración en los brotes de los tres flujos vegetativos, ésta ocurrió más temprano en clima templado que en cálido. Después de la emergencia, los brotes del flujo de invierno requirieron más tiempo para alcanzar la determinación irreversible a la floración que en primavera y verano. La determinación irreversible a la floración en brotes de los flujos de invierno, primavera y verano ocurrió del 30 de mayo al 23 de julio, del 28 de mayo al 26 de septiembre y del 10 de junio al 15 de septiembre, respectivamente, y de 29 a 42 días más temprano en los huertos sin riego. En el desarrollo floral, el número de yemas determinadas irreversiblemente a la floración variaron de 3 a 4 en los brotes de invierno, de 3 a 5 en primavera y de 1 a 4 en verano.The aim of this study was to specify periods in which occurs irreversible determination to flowering in apical bud of vegetative sprout for winter, spring and summer flows in avocado orchards with and without irrigation set under four climatic conditions. The study was carried out during 2006-2008, in six commercial orchards for avocado 'Hass' in State of Michoacán, Mexico. In each orchard 20 trees were selected and in each one 30 sprouts of each vegetative flow were labeled

  17. Cell Death Characterization In Tumor Constructs Using Irreversible Electroporation

    OpenAIRE

    Prokop, Katherine Jane

    2013-01-01

    Cell Death Characterization in Tumor Constructs Using Irreversible Electroporation Katherine Jane Prokop ABSTRACT Pancreatic and prostate cancer are both prevalent cancers in the United States with pancreatic being one of the most aggressive of all cancers and prostate cancer being one of the most common, ranking as the number one cancer in men. Treatment of both cancers can be quite challenging as the anatomy of the pancreas and prostate, as well as the development and diagnos...

  18. Advancements in Irreversible Electroporation for the Treatment of Cancer

    OpenAIRE

    Arena, Christopher Brian

    2013-01-01

        Irreversible electroporation has recently emerged as an effective focal ablation technique. When performed clinically, the procedure involves placing electrodes into, or around, a target tissue and applying a series of short, but intense, pulsed electric fields. Oftentimes, patient specific treatment plans are employed to guide procedures by merging medical imaging with algorithms for determining the electric field distribution in the tissue. The electric field dictates treatment outcomes...

  19. Irreversible Electroporation: A Novel Image-Guided Cancer Therapy

    OpenAIRE

    Lee, Edward W.; Thai, Susan; Kee, Stephen T.

    2010-01-01

    Irreversible electroporation (IRE) is a novel tumor ablation technique using a non-thermal energy to create innumerable permanent nanopores in the cell membrane to disrupt cellular homeostasis. This disruption of cellular homeostasis initiates apoptosis which leads to permanent cell death. In our translational research, we have demonstrated that IRE can be a safe, fast and powerful method of tumor treatment. In this review, we present an overview of IRE ablation including a brief history of I...

  20. Study of irreversible thermochromic ink application on textiles

    OpenAIRE

    Canal Barnils, Cristina; Villeger, Sandrine; Erra Serrabasa, Pilar; Ricard, André

    2009-01-01

    In the development of new products or new applications of known products, investigations have to be carried out concerning the choice of the kind of thermochromic matter, support, application form, concerning the evolution of colour change and stability versus imposed external parameters. The present paper studies the application of an irreversible thermochromic ink for the development of new high added value textiles, which may be prone to applications such as plasma treatments at low ...

  1. Irreversible Investment, Capacity Choice, and the Value of the Firm

    OpenAIRE

    Robert S. Pindyck

    1986-01-01

    A model of capacity choice and utilization is developed consistent with value maximization when investment is irreversible and future demand is uncertain. Investment requires the full value of a marginal unit of capacity to be at least as large as its full cost. The former includes the value of the firms option not to utilize the unit, and the latter includes the opportunity cost of exercising the investment option. We show that for moderate amounts of uncertainty, the firm's optimal capacity...

  2. Irreversible Electroporation for Focal Ablation at the Porta Hepatis

    International Nuclear Information System (INIS)

    Patients with chemotherapy-refractory liver metastases who are not candidates for surgery may be treated with focal ablation techniques with established survival benefits. Irreversible electroporation is the newest of these and has the putative advantages of a nonthermal action, preventing damage to adjacent biliary structures and bowel. This report describes the use of irreversible electroporation in a 61-year-old man with a solitary chemoresistant liver metastasis unsuitable for radiofrequency ablation as a result of its proximity to the porta hepatis. At 3 months, tumor size was decreased on computed tomography from 28 × 19 to 20 × 17 mm, representing stable disease according to the response evaluation criteria in solid tumors. This corresponded to a decrease in tumor volume size from 5.25 to 3.16 cm3. There were no early or late complications. Chemoresistant liver metastases in the proximity of the porta hepatis that are considered to be too high a risk for conventional surgery or thermal ablation may be considered for treatment by the novel ablation technique of irreversible electroporation.

  3. Rapid Detection of Irreversible Acetylcholineasterase Inhibitor by Mass Spectrometry Assay

    Institute of Scientific and Technical Information of China (English)

    蔡婷婷; 张立; 汪蓉; 梁晨; 赵武生; 傅得锋; 张玉荣; 郭寅龙

    2012-01-01

    Here we developed a rapid method to detect acetylcholinesterase (ACHE) activity by matrix-assisted laser de- sorption/ionization Fourier transform mass spectrometry (MALDI-FTMS) for screening irreversible AChE inhibi- tors. Due to its good salt-tolerance and low sample consumption, MALDI-FTMS could facilitate rapid detection, especially detection in real application. AChE activity was determined through calculating abundance of substrate and product in mass spectrometry. By this approach, we investigated the relation of organophosphorous (OP) con- centrations and AChE inhibition. Shown in different inhibition curves from different OP pesticides, enzyme inhibi- tions still kept good correlation with concentration of OPs. Finally, this AChE-inhibited method was applied to screen whole bloods of four decedents and discuss their death reason. In contrast to healthy persons, three of dece- dents showed low AChE activity, and probably died for irreversible AChE inhibitors. Through the following de- tecting in GC-MS/MS, the possible death reason of these three decedents was confirmed, and another decedent actually died for sumicidin, a non-AChE inhibitor. It demonstrated that screening irreversible AChE inhibitors by detecting enzyme activity in MALDI-FTMS provided fast and accurate analysis results and excluded another toxicants not functioning on ACHE. This method offered alternative choices for indicating the existence of enzyme inhibitors.

  4. Irreversibility in energy processes: Non-dimensional quantification and balance

    Science.gov (United States)

    Pons, Michel

    2004-06-01

    The concept of thermodynamic efficiency (ratio of real cycle efficiency by Carnot efficiency) is well-known. The concept of numbers of entropy-production and of exergy-loss proposed by A. Bejan are also known, but rarely used. The present study firstly evidences that these two last numbers are actually identical, thus being a common number of irreversibility, independent of the method used for obtaining it. The study also evidences a non-dimensional irreversibility balance that applies to any energy conversion process. This balance correlates the thermodynamic efficiency of a whole process (which in most cases equals the exergetic efficiency) and the numbers of irreversibility of the different components or sub-processes involved in this process. Moreover, the basic additivity of entropy-productions and exergy-losses is maintained in this balance. This balance applies to the basic cycles (heat-engines, refrigerators, heat-pumps and heat-transformers), either work- or heat-powered. It also applies to more complex cycles (heat-powered cycles consuming electricity, four-temperature heat-powered cycles, cogeneration processes), thus giving a robust framework for analyzing these cycles.

  5. Irreversible Electroporation for Focal Ablation at the Porta Hepatis

    Energy Technology Data Exchange (ETDEWEB)

    Kasivisvanathan, Veeru, E-mail: vk103@ic.ac.uk [Imperial College London, Department of Radiology (United Kingdom); Thapar, Ankur, E-mail: a.thapar09@imperial.ac.uk; Oskrochi, Youssof, E-mail: Youssof.Oskrochi09@imperial.ac.uk [Imperial College London, Department of Surgery and Cancer (United Kingdom); Picard, John, E-mail: John.picard@imperial.nhs.uk [Imperial College Healthcare NHS Trust, Department of Anaesthesia (United Kingdom); Leen, Edward L. S., E-mail: Edward.leen@imperial.ac.uk [Imperial College London, Department of Radiology (United Kingdom)

    2012-12-15

    Patients with chemotherapy-refractory liver metastases who are not candidates for surgery may be treated with focal ablation techniques with established survival benefits. Irreversible electroporation is the newest of these and has the putative advantages of a nonthermal action, preventing damage to adjacent biliary structures and bowel. This report describes the use of irreversible electroporation in a 61-year-old man with a solitary chemoresistant liver metastasis unsuitable for radiofrequency ablation as a result of its proximity to the porta hepatis. At 3 months, tumor size was decreased on computed tomography from 28 Multiplication-Sign 19 to 20 Multiplication-Sign 17 mm, representing stable disease according to the response evaluation criteria in solid tumors. This corresponded to a decrease in tumor volume size from 5.25 to 3.16 cm{sup 3}. There were no early or late complications. Chemoresistant liver metastases in the proximity of the porta hepatis that are considered to be too high a risk for conventional surgery or thermal ablation may be considered for treatment by the novel ablation technique of irreversible electroporation.

  6. Ecological Optimization and Parametric Study of an Irreversible Regenerative Modified Brayton Cycle with Isothermal Heat Addition

    OpenAIRE

    Vivek Tiwari; Subhash Chandra Kaushik; Sudhir Kumar Tyagi

    2003-01-01

    Abstract: An ecological optimization along with a detailed parametric study of an irreversible regenerative Brayton heat engine with isothermal heat addition have been carried out with external as well as internal irreversibilities. The ecological function is defined as the power output minus the power loss (irreversibility) which is ambient temperature times the entropy generation rate. The external irreversibility is due to finite temperature difference between the heat engine and the exter...

  7. Linking Drugs to Obscure Illnesses: Lessons from Pure Red Cell Aplasia, Nephrogenic Systemic Fibrosis, and Reye’s Syndrome. A Report From the Southern Network on Adverse Reactions (SONAR)

    OpenAIRE

    Bennett, Charles L.; Starko, Karen M.; Thomsen, Henrik S; Cowper, Shawn; Sartor, Oliver; Macdougall, Iain C.; Qureshi, Zaina P; Bookstaver, P. Brandon; Miller, April D; Norris, LeAnn B.; Xirasagar, Sudha; Trenery, Alyssa; Lopez, Isaac; Kahn, Adam; Murday, Alanna

    2012-01-01

    Identification of serious adverse drug reactions (sADRS) associated with commonly used drugs can elude detection for years. Reye’s syndrome (RS), nephrogenic systemic fibrosis (NSF), and pure red cell aplasia (PRCA) among chronic kidney disease (CKD) patients were recognized in 1951, 2000, and 1998, respectively. Reports associating these syndromes with aspirin, gadodiamide, and epoetin, were published 29, 6, and 4 years later, respectively. We obtained primary information from clinicians who...

  8. Dimensional Stability of Color-Changing Irreversible Hydrocolloids after Disinfection

    Directory of Open Access Journals (Sweden)

    Khaledi AAR

    2015-03-01

    Full Text Available Statement of Problem: Disinfection of dental impressions is a weak point in the dental hygiene chain. In addition, dental office personnel and dental technicians are endangered by cross-contamination. Objectives: This study aimed to investigate the dimensional stability of two color-changing irreversible hydrocolloid materials (IH after disinfection with glutaraldehyde. Materials and Methods: In this in vitro study, impressions were made of a master maxillary arch containing three reference inserts on the occlucal surface of the left and right maxillary second molars and in the incisal surface of the maxillary central incisors. Two types of color-changing irreversible hydrocolloid (tetrachrom, cavex were used. Glutaraldehyde 2% was used in two methods of spraying and immersion to disinfect the impressions. The control group was not disinfected. Casts were made of type IV gypsum. The linear dimensional change of the stone casts was measured with a profile projector. For statistical analysis, Kruskall-Wallis and Mann-Witney tests were used (α=0.05. Results: By immersion method, the casts fabricated from tetrachrom were 0.36% larger in the anteroposterior (AP and 0.05% smaller in cross arch (CA dimensions; however, the casts prepared after spraying of tetrachrom were 0.44% larger in the AP and 0.10% smaller in CA dimensions. The casts made from Cavex were 0.05% smaller in the AP and 0.02% smaller in CA dimensions after spraying and 0.01% smaller in the AP and 0.003% smaller in CA dimensions after immersion. Generally there were not significant differences in AP and CA dimensions of the experimental groups compared to the control (p > 0.05. Conclusions: Disinfection of the tested color-changing irreversible hydrocolloids by glutaraldahyde 2% did not compromise the accuracy of the obtained casts.

  9. Differential description and irreversibility of depolarizing light-matter interactions

    CERN Document Server

    Fade, Julien

    2016-01-01

    The widely-used Jones and Mueller differential polarization calculi allow non-depolarizing deterministic polarization interactions, known to be elements of the $SO^+(1,3)$ Lorentz group, to be described in an efficient way. In this Letter, a stochastic differential Jones formalism is shown to provide a clear physical insight on light depolarization, which arises from the interaction of polarized light with a random medium showing fluctuating anisotropic properties. Based on this formalism, several "intrinsic" depolarization metrics naturally arise to efficiently characterize light depolarization in a medium, and an irreversibility property of depolarizing transformations is finally established.

  10. Irreversible inhibition of epithelial sodium channels by ultraviolet irradiation.

    OpenAIRE

    Cuthbert, A W; Fanestil, D. D.; Herrera, F. C.; Pryn, S. J.

    1982-01-01

    1 The effects of u.v. irradiation at 254 nm and 350 nm on sodium transport across frog skin epithelium have been investigated. 2 Irradiation at 254 nm but not at 350 nm produces a dose-dependent, functionally selective blockade of sodium transport. The effect is apparently due to the irreversible closure of apical sodium channels. 3 The amiloride-sensitive conductance was directly related to sodium transport as measured by short circuit current (SCC) both in normal and irradiated tissues, alt...

  11. Typical pure nonequilibrium steady states and irreversibility for quantum transport

    Science.gov (United States)

    Monnai, Takaaki; Yuasa, Kazuya

    2016-07-01

    It is known that each single typical pure state in an energy shell of a large isolated quantum system well represents a thermal equilibrium state of the system. We show that such typicality holds also for nonequilibrium steady states (NESS's). We consider a small quantum system coupled to multiple infinite reservoirs. In the long run, the total system reaches a unique NESS. We identify a large Hilbert space from which pure states of the system are to be sampled randomly and show that the typical pure states well describe the NESS. We also point out that the irreversible relaxation to the unique NESS is important to the typicality of the pure NESS's.

  12. Intrinsic irreversibility limits the efficiency of multidimensional molecular motors.

    Science.gov (United States)

    Jack, M W; Tumlin, C

    2016-05-01

    We consider the efficiency limits of Brownian motors able to extract work from the temperature difference between reservoirs or from external thermodynamic forces. These systems can operate in a variety of modes, including as isothermal engines, heat engines, refrigerators, and heat pumps. We derive analytical results showing that certain classes of multidimensional Brownian motor, including the Smoluchowski-Feynman ratchet, are unable to attain perfect efficiency (Carnot efficiency for heat engines). This demonstrates the presence of intrinsic irreversibilities in their operating mechanism. We present numerical simulations showing that in some cases the loss process that limits efficiency is associated with vortices in the probability current.

  13. Intrinsic irreversibility limits the efficiency of multidimensional molecular motors

    Science.gov (United States)

    Jack, M. W.; Tumlin, C.

    2016-05-01

    We consider the efficiency limits of Brownian motors able to extract work from the temperature difference between reservoirs or from external thermodynamic forces. These systems can operate in a variety of modes, including as isothermal engines, heat engines, refrigerators, and heat pumps. We derive analytical results showing that certain classes of multidimensional Brownian motor, including the Smoluchowski-Feynman ratchet, are unable to attain perfect efficiency (Carnot efficiency for heat engines). This demonstrates the presence of intrinsic irreversibilities in their operating mechanism. We present numerical simulations showing that in some cases the loss process that limits efficiency is associated with vortices in the probability current.

  14. Fluctuations in the number of irreversibly adsorbed particles

    Science.gov (United States)

    Adamczyk, Zbigniew; Szyk-Warszyńska, Lilianna; Siwek, B.; Weroński, P.

    2000-12-01

    Fluctuations in the number of colloid particles adsorbed irreversibly under pure diffusion transport conditions were determined as a function of surface density and ionic strength of the suspension. The experiments were carried out for monodisperse polystyrene latex particles of micrometer size range adsorbing irreversibly at mica surface. The surface density of adsorbed particles at various areas was determined using the direct microscope observation method. A new experimental cell was used enabling in situ observations of particles adsorption under conditions of negligible gravity effects. It was found that the particle density fluctuations for high ionic strength were in a good agreement with the theoretical results derived from the random sequential adsorption (RSA) model. Also, the theoretical results stemming from the equilibrium scaled particle theory reflected the experimental data satisfactorily. For lower ionic strength a deviation from the hard sphere behavior was experimentally demonstrated. This effect due to the repulsive electrostatic interactions was interpreted in terms of the effective hard particle concept. The universal dependence of variance on particle density obtained in this way was found in a good agreement with the RSA model for all ionic strength. These results proved that fluctuations in particle density of monolayer formed under diffusional conditions differ fundamentally from these obtained under ballistic transport conditions.

  15. Irreversible entropy model for damage diagnosis in resistors

    Energy Technology Data Exchange (ETDEWEB)

    Cuadras, Angel, E-mail: angel.cuadras@upc.edu; Crisóstomo, Javier; Ovejas, Victoria J.; Quilez, Marcos [Instrumentation, Sensor and Interfaces Group, Electronic Engineering Department, Escola d' Enginyeria de Telecomunicació i Aeronàutica de Castelldefels EETAC, Universitat Politècnica de Catalunya, Barcelona Tech (UPC), Castelldefels-Barcelona (Spain)

    2015-10-28

    We propose a method to characterize electrical resistor damage based on entropy measurements. Irreversible entropy and the rate at which it is generated are more convenient parameters than resistance for describing damage because they are essentially positive in virtue of the second law of thermodynamics, whereas resistance may increase or decrease depending on the degradation mechanism. Commercial resistors were tested in order to characterize the damage induced by power surges. Resistors were biased with constant and pulsed voltage signals, leading to power dissipation in the range of 4–8 W, which is well above the 0.25 W nominal power to initiate failure. Entropy was inferred from the added power and temperature evolution. A model is proposed to understand the relationship among resistance, entropy, and damage. The power surge dissipates into heat (Joule effect) and damages the resistor. The results show a correlation between entropy generation rate and resistor failure. We conclude that damage can be conveniently assessed from irreversible entropy generation. Our results for resistors can be easily extrapolated to other systems or machines that can be modeled based on their resistance.

  16. Essays on oil price volatility and irreversible investment

    Science.gov (United States)

    Pastor, Daniel J.

    In chapter 1, we provide an extensive and systematic evaluation of the relative forecasting performance of several models for the volatility of daily spot crude oil prices. Empirical research over the past decades has uncovered significant gains in forecasting performance of Markov Switching GARCH models over GARCH models for the volatility of financial assets and crude oil futures. We find that, for spot oil price returns, non-switching models perform better in the short run, whereas switching models tend to do better at longer horizons. In chapter 2, I investigate the impact of volatility on firms' irreversible investment decisions using real options theory. Cost incurred in oil drilling is considered sunk cost, thus irreversible. I collect detailed data on onshore, development oil well drilling on the North Slope of Alaska from 2003 to 2014. Volatility is modeled by constructing GARCH, EGARCH, and GJR-GARCH forecasts based on monthly real oil prices, and realized volatility from 5-minute intraday returns of oil futures prices. Using a duration model, I show that oil price volatility generally has a negative relationship with the hazard rate of drilling an oil well both when aggregating all the fields, and in individual fields.

  17. Pure red cell aplasia due to parvovirus B19 infection after liver transplantation: A case report and review of the literature

    Institute of Scientific and Technical Information of China (English)

    Ting-Bo Liang; Shu-Sen Zheng; Dong-Lin Li; Jun Yu; Xue-Li Bai; Liang Liang; Shi-Guo Xu; Wei-Lin Wang; Yan Shen; Min Zhang

    2007-01-01

    Pure red cell aplasia (PRCA) due to parvovirus B19(PVB19) infection after solid organ transplantation has been rarely reported and most of the cases were renal transplant recipients. Few have been described after liver transplantation. Moreover, little information on the management of this easily recurring disease is available at present. We describe the first case of a Chinese liver transplant recipient with PVB19-induced PRCA during immunosuppressive therapy. The patient suffered from progressive anemia with the lowest hemoglobin level of 21 g/L. Bone marrow biopsy showed selectively inhibited erythropoiesis with giant pronormoblasts. Detection of PVB19-DNA in serum with quantitative polymerase chain reaction (PCR) revealed a high level of viral load.After 2 courses of intravenous immunoglobulin (IVIG)therapy, bone marrow erythropoiesis recovered with his hemoglobin level increased to 123 g/L. He had a lowlevel PVB19 load for a 5-mo follow-up period without recurrence of PRCA, and finally the virus was cleared.Our case indicates that clearance of PVB19 by IVIG in transplant recipients might be delayed after recovery of anemia.

  18. Rat liver regeneration following ablation with irreversible electroporation.

    Science.gov (United States)

    Golberg, Alexander; Bruinsma, Bote G; Jaramillo, Maria; Yarmush, Martin L; Uygun, Basak E

    2016-01-01

    During the past decade, irreversible electroporation (IRE) ablation has emerged as a promising tool for the treatment of multiple diseases including hepatic cancer. However, the mechanisms behind the tissue regeneration following IRE ablation have not been investigated. Our results indicate that IRE treatment immediately kills the cells at the treatment site preserving the extracellular architecture, in effect causing in vivo decellularization. Over the course of 4 weeks, progenitor cell differentiation, through YAP and notch pathways, together with hepatocyte expansion led to almost complete regeneration of the ablated liver leading to the formation of hepatocyte like cells at the ablated zone. We did not observe significant scarring or tumor formation at the regenerated areas 6 months post IRE. Our study suggests a new model to study the regeneration of liver when the naïve extracellular matrix is decellularized in vivo with completely preserved extracellular architecture. PMID:26819842

  19. Sub-kBT micro-electromechanical irreversible logic gate.

    Science.gov (United States)

    López-Suárez, M; Neri, I; Gammaitoni, L

    2016-01-01

    In modern computers, computation is performed by assembling together sets of logic gates. Popular gates like AND, OR and XOR, processing two logic inputs and yielding one logic output, are often addressed as irreversible logic gates, where the sole knowledge of the output logic value is not sufficient to infer the logic value of the two inputs. Such gates are usually believed to be bounded to dissipate a finite minimum amount of energy determined by the input-output information difference. Here we show that this is not necessarily the case, by presenting an experiment where a OR logic gate, realized with a micro-electromechanical cantilever, is operated with energy well below the expected limit, provided the operation is slow enough and frictional phenomena are properly addressed. PMID:27350333

  20. Sub-kBT micro-electromechanical irreversible logic gate

    Science.gov (United States)

    López-Suárez, M.; Neri, I.; Gammaitoni, L.

    2016-06-01

    In modern computers, computation is performed by assembling together sets of logic gates. Popular gates like AND, OR and XOR, processing two logic inputs and yielding one logic output, are often addressed as irreversible logic gates, where the sole knowledge of the output logic value is not sufficient to infer the logic value of the two inputs. Such gates are usually believed to be bounded to dissipate a finite minimum amount of energy determined by the input-output information difference. Here we show that this is not necessarily the case, by presenting an experiment where a OR logic gate, realized with a micro-electromechanical cantilever, is operated with energy well below the expected limit, provided the operation is slow enough and frictional phenomena are properly addressed.

  1. Immersion disinfection of irreversible hydrocolloid impressions. Part 1: Microbiology.

    Science.gov (United States)

    Schwartz, R S; Bradley, D V; Hilton, T J; Kruse, S K

    1994-01-01

    This study evaluated the effectiveness of four disinfectants for irreversible hydrocolloid impressions. Impressions were made of a sterile metal model of the maxillary arch that had been contaminated with one of the following bacteria: Staphylococcus aureus, Salmonella choleraesuis, Pseudomonas aeruginosa, Mycobacterium bovis, or Bacillus subtilis. The impressions were cultured before and after immersion in one of the following disinfectants: lodofive, OMC II, 0.525% sodium hypochlorite, or Alcide LD. Alcide LD achieved a 4-log10 (99.99%) or greater reduction in colony forming units for all five organisms plus mixed oral flora. Sodium hypochlorite achieved a 4-log10 reduction in three of the five organisms and mixed oral flora. Iodofive and OMC II were ineffective against all test organisms and mixed oral flora.

  2. Irreversible degradation of quantum coherence under relativistic motion

    Science.gov (United States)

    Wang, Jieci; Tian, Zehua; Jing, Jiliang; Fan, Heng

    2016-06-01

    We study the dynamics of quantum coherence under Unruh thermal noise and seek under which condition the coherence can be frozen in a relativistic setting. We find that the frozen condition is either (i) the initial state is prepared as an incoherence state or (ii) the detectors have no interaction with the external field. That is to say, the decoherence of the detectors' quantum state is irreversible under the influence of thermal noise induced by Unruh radiation. It is shown that quantum coherence approaches zero only in the limit of an infinite acceleration, while quantum entanglement could reduce to zero for a finite acceleration. It is also demonstrated that the robustness of quantum coherence is better than entanglement under the influence of the atom-field interaction for an extremely large acceleration. Therefore, quantum coherence is more robust than entanglement in an accelerating system and the coherence-type quantum resources are more accessible for relativistic quantum information processing tasks.

  3. Immersion disinfection of irreversible hydrocolloid impressions. Part 1: Microbiology.

    Science.gov (United States)

    Schwartz, R S; Bradley, D V; Hilton, T J; Kruse, S K

    1994-01-01

    This study evaluated the effectiveness of four disinfectants for irreversible hydrocolloid impressions. Impressions were made of a sterile metal model of the maxillary arch that had been contaminated with one of the following bacteria: Staphylococcus aureus, Salmonella choleraesuis, Pseudomonas aeruginosa, Mycobacterium bovis, or Bacillus subtilis. The impressions were cultured before and after immersion in one of the following disinfectants: lodofive, OMC II, 0.525% sodium hypochlorite, or Alcide LD. Alcide LD achieved a 4-log10 (99.99%) or greater reduction in colony forming units for all five organisms plus mixed oral flora. Sodium hypochlorite achieved a 4-log10 reduction in three of the five organisms and mixed oral flora. Iodofive and OMC II were ineffective against all test organisms and mixed oral flora. PMID:7802909

  4. Irreversible Collective Migration of Cyanobacteria in Eutrophic Conditions

    CERN Document Server

    Dervaux, Julien; Brunet, Philippe

    2015-01-01

    In response to natural or anthropocentric pollutions coupled to global climate changes, microorganisms from aquatic environments can suddenly accumulate on water surface. These dense suspensions, known as blooms, are harmful to ecosystems and significantly degrade the quality of water resources. In order to determine the physico-chemical parameters involved in their formation and quantitatively predict their appearance, we successfully reproduced irreversible cyanobacterial blooms in vitro. By combining chemical, biochemical and hydrodynamic evidences, we identify a mechanism, unrelated to the presence of internal gas vesicles, allowing the sudden collective upward migration in test tubes of several cyanobacterial strains (Microcystis aeruginosa PCC 7005, Microcystis aeruginosa PCC 7806 and Synechocystis sp. PCC 6803). The final state consists in a foamy layer of biomass at the air-liquid interface, in which micro-organisms remain alive for weeks, the medium lying below being almost completely depleted of cya...

  5. A systematic comprehensive approach to management of irreversible facial paralysis.

    Science.gov (United States)

    Douglas, Raymond S; Gausas, Roberta E

    2003-02-01

    Irreversible facial palsy (IFP) presents a multitude of problems arising from a paretic periorbital and facial complex, the solutions to which cross the spectrum of multiple specialties. The process of facial rehabilitation can be simplified by subdividing the face into functional units. These units consist of the brow complex, the periorbital complex, the midface complex, and the lower face/oral complex. Although all of these units are interrelated and influence each other, careful study of the deformity and symptoms of each unit yields a coherent approach and customized surgical plan. The following provides a complete evaluation method for the surgeon to review and customize an approach to the individual patient's needs and desires. Facial rehabilitation must be tailored to each individual, addressing both functional as well as aesthetic concerns for each facial unit.

  6. Focal Therapy of Prostate Cancer Using Irreversible Electroporation.

    Science.gov (United States)

    Valerio, Massimo; Ahmed, Hashim U; Emberton, Mark

    2015-09-01

    Focal therapy is a novel strategy that attempts to enhance the therapeutic ratio of standard radical treatment in prostate cancer. Irreversible electroporation (IRE) has some inherent characteristics that may be ideal for focal therapy. Precise confined ablation in the treatment area obtained via nonthermal damage with potential for minimal toxicity to surrounding structures may lead to optimal treatment with improved preservation of continence and erectile function. Initial data of focal IRE of the prostate are encouraging although further assessment is awaited to confirm these findings using robust methodology. In this article, we provide a comprehensive step-by-step description of our technique to deliver focal IRE in selected men with localized prostate cancer located in a discrete area of the prostate.

  7. Advertising and Irreversible Opinion Spreading in Complex Social Networks

    Science.gov (United States)

    Candia, Julián

    Irreversible opinion spreading phenomena are studied on small-world and scale-free networks by means of the magnetic Eden model, a nonequilibrium kinetic model for the growth of binary mixtures in contact with a thermal bath. In this model, the opinion of an individual is affected by those of their acquaintances, but opinion changes (analogous to spin flips in an Ising-like model) are not allowed. We focus on the influence of advertising, which is represented by external magnetic fields. The interplay and competition between temperature and fields lead to order-disorder transitions, which are found to also depend on the link density and the topology of the complex network substrate. The effects of advertising campaigns with variable duration, as well as the best cost-effective strategies to achieve consensus within different scenarios, are also discussed.

  8. The Social Cost of Stochastic and Irreversible Climate Change

    Science.gov (United States)

    Cai, Y.; Judd, K. L.; Lontzek, T.

    2013-12-01

    Many scientists are worried about climate change triggering abrupt and irreversible events leading to significant and long-lasting damages. For example, a rapid release of methane from permafrost may lead to amplified global warming, and global warming may increase the frequency and severity of heavy rainfall or typhoon, destroying large cities and killing numerous people. Some elements of the climate system which might exhibit such a triggering effect are called tipping elements. There is great uncertainty about the impact of anthropogenic carbon and tipping elements on future economic wellbeing. Any rational policy choice must consider the great uncertainty about the magnitude and timing of global warming's impact on economic productivity. While the likelihood of tipping points may be a function of contemporaneous temperature, their effects are long lasting and might be independent of future temperatures. It is assumed that some of these tipping points might occur even in this century, but also that their duration and post-tipping impact are uncertain. A faithful representation of the possibility of tipping points for the calculation of social cost of carbon would require a fully stochastic formulation of irreversibility, and accounting for the deep layer of uncertainties regarding the duration of the tipping process and also its economic impact. We use DSICE, a DSGE extension of the DICE2007 model of William Nordhaus, which incorporates beliefs about the uncertain economic impact of possible climate tipping events and uses empirically plausible parameterizations of Epstein-Zin preferences to represent attitudes towards risk. We find that the uncertainty associated with anthropogenic climate change imply carbon taxes much higher than implied by deterministic models. This analysis indicates that the absence of uncertainty in DICE2007 and similar IAM models may result in substantial understatement of the potential benefits of policies to reduce GHG emissions.

  9. Palliative treatment of presacral recurrence of endometrial cancer using irreversible electroporation: a case report

    OpenAIRE

    Niessen, Christoph; Jung, Ernst-Michael; Schreyer, Andreas G; Wohlgemuth, Walter A; Trabold, Benedikt; Hahn, Joachim; Rechenmacher, Michael; Stroszczynski, Christian; Wiggermann, Philipp

    2013-01-01

    INTRODUCTION: Irreversible electroporation (IRE) is a new minimally invasive tumor ablation technique which induces irreversible disruption of cell membrane integrity by changing the transmembrane potential resulting in cell death. Irreversible electroporation is currently undergoing clinical investigation as local tumor therapy for malignant liver and lung lesions. This is the first case report to describe the successful palliative ablation of a presacral recurrence of an endometrial canc...

  10. Inertial effects during irreversible meniscus reconfiguration in angular pores

    Science.gov (United States)

    Ferrari, Andrea; Lunati, Ivan

    2014-12-01

    In porous media, the dynamics of the invading front between two immiscible fluids is often characterized by abrupt reconfigurations caused by local instabilities of the interface. As a prototype of these phenomena we consider the dynamics of a meniscus in a corner as it can be encountered in angular pores. We investigate this process in detail by means of direct numerical simulations that solve the Navier-Stokes equations in the pore space and employ the Volume of Fluid method (VOF) to track the evolution of the interface. We show that for a quasi-static displacement, the numerically calculated surface energy agrees well with the analytical solutions that we have derived for pores with circular and square cross sections. However, the spontaneous reconfigurations are irreversible and cannot be controlled by the injection rate: they are characterized by the amount of surface energy that is spontaneously released and transformed into kinetic energy. The resulting local velocities can be orders of magnitude larger than the injection velocity and they induce damped oscillations of the interface that possess their own time scales and depend only on fluid properties and pore geometry. In complex media (we consider a network of cubic pores) reconfigurations are so frequent and oscillations last long enough that increasing inertial effects leads to a different fluid distribution by influencing the selection of the next pore to be invaded. This calls into question simple pore-filling rules based only on capillary forces. Also, we demonstrate that inertial effects during irreversible reconfigurations can influence the work done by the external forces that is related to the pressure drop in Darcy's law. This suggests that these phenomena have to be considered when upscaling multiphase flow because local oscillations of the menisci affect macroscopic quantities and modify the constitutive relationships to be used in macro-scale models. These results can be extrapolated to other

  11. ESTIMATION OF IRREVERSIBLE DAMAGEABILITY AT FATIGUE OF CARBON STEEL

    Directory of Open Access Journals (Sweden)

    I. O. Vakulenko

    2014-04-01

    Full Text Available Purpose. Damageability estimation of carbon steel in the conditions of cyclic loading. Methodology. The steel fragments of railway wheel rim and rail head served as material for research with chemical composition 0.65 % С, 0.67 % Mn, 0.3 % Si, 0.027 % P, 0.028 % S и 0.7 % C, 0.82 % Mn, 0.56 % Si, 0.025 % P, 0.029 % S accordingly. The microstructure of tested steels corresponded to the state of metal after a hot plastic deformation. The fatigue research was conducted in the conditions of symmetric bend using the proof-of-concept machine of type «Saturn-10». Full Wohler diagrams and the lines corresponding to forming of sub-and micro cracks were constructed. The distribution analysis of internal stresses in the metal under cyclic loading was carried out using the microhardness tester of PMT-3 type.Findings. On the basis of fatigue curves for high-carbon steels analysis the positions of borders dividing the areas of convertible and irreversible damages were determined. The article shows that with the growth of carbon concentration in the steel at invariability of the structural state an increase of fatigue limit is observed. At the same time the acceleration of processes, which determine transition terms from the stage of forming of submicrocracks to the microcracks occurs. The research of microhardness distribution in the metal after destruction confirmed the nature of carbon amount influence on the carbon steel characteristics. Originality. Regardless on the stages of breakdown site forming the carbon steels behavior at a fatigue is determined by the ration between the processes of strengthening and softening. At a cyclic loading the heterogeneity of internal stresses distribution decreases with the increase of distance from the destruction surface. Analysis of metal internal restructuring processes at fatigue loading made it possible to determine that at the stages prior to incubation period in the metal microvolumes the cells are already

  12. A minimal dissipation type-based classification in irreversible thermodynamics and microeconomics

    Science.gov (United States)

    Tsirlin, A. M.; Kazakov, V.; Kolinko, N. A.

    2003-10-01

    We formulate the problem of finding classes of kinetic dependencies in irreversible thermodynamic and microeconomic systems for which minimal dissipation processes belong to the same type. We show that this problem is an inverse optimal control problem and solve it. The commonality of this problem in irreversible thermodynamics and microeconomics is emphasized.

  13. Lipoxygenase is irreversibly inactivated by the hydroperoxides formed from the enynoic analogues of linoleic acid

    NARCIS (Netherlands)

    Vliegenthart, J.F.G.; Nieuwenhuizen, W.F.; Kerk-van Hoof, A. van der; Lenthe, J.H. van; Schaik, R.C. van; Versluis, K.; Veldink, G.A.

    1997-01-01

    Triple bond analogues of natural fatty acids irreversibly inactivate lipoxygenase during their enzymatic conversion [Nieuwenhuizen, W. F., et al. (1995) Biochemistry 34, 10538-10545]. To gain insight into the mechanism of the irreversible inactivation of soybean lipoxygenase-1, we studied the enzyma

  14. A Minimal Dissipation Type-Based Classification in Irreversible Thermodynamics and Microeconomics

    OpenAIRE

    A. M. Tsirlin; Valdimir Kazakov; N. A. Kolinko

    2003-01-01

    We formulate the problem of finding classes of kinetic dependencies in irreversible thermodynamic and microeconomic systems for which minimal dissipation processes belong to the same type. We show that this problem is an inverse optimal control problem and solve it. The commonality of this problem in irreversible thermodynamics and microeconomics is emphasized.

  15. Rare birth defects associated with Morgagni hernia and segmental aplasia of uterine horn in bitch: Case reportDefeitos congênitos raros em cadela – relato de caso

    Directory of Open Access Journals (Sweden)

    Ricardo Santana de Lima

    2013-09-01

    Full Text Available Birth defects, deformities or abnormalities are terms used to describe developmental defects present at birth, most of which are rare in bitches. We report the case of a six-month old mongrel bitch corpse, which, when subjected to an anatomotopographic study revealed the presence of rare birth defects as Morgagni hernia and segmental aplasia of the right uterine horn with its attachment to the transverses muscle of abdominis. In association with HM, we observed the presence of dextrocardia and a defect of the abdominal wall supraumbilical characteristic of incompletely Pentalogy of Cantrell’s, syndrome so far described only in humans. In association with segmental aplasia of the uterine horn, we observed the ipsilateral presence of the renal hypoplasia and ureteral agenesis. The diagnosis of those abnormalities was based on anatomical findings and confirmed histologically. Despite the rarity and complexity of the abnormalities first described in bitches, the literature suggested that the prognosis may be favorable to the life of the animal. However, early diagnosis is essential to avoid the potential complications of those diseasesDefeitos congênitos, deformidades ou anormalidades são termos usados para descrever defeitos no desenvolvimento presentes ao nascimento. A maioria destes, como a aplasia segmentar uterina, é de ocorrência rara em cadelas. Relata-se o caso de um cadáver de cadela, sem raça definida, de seis meses de idade, que ao ser submetido ao estudo anatomotopográfico revelou a presença de aplasia segmentar uterina (ASU associada à hérnia de Morgagni (HM, agenesia ureteral (AU e hipoplasia renal direita (HR. Além destas anormalidades, foi observada a presença de dextrocardia e de um defeito da parede abdominal supraumbilical, que caracterizam a forma incompleta da pentalogia de Cantrell, só descrita em humanos. O diagnóstico destas anormalidades foi baseado nos achados anatômicos e confirmado histologicamente. A

  16. Reversibility and irreversibility from an initial value formulation

    Energy Technology Data Exchange (ETDEWEB)

    Muriel, A., E-mail: amadormuriel@fas.harvard.edu

    2013-07-15

    From a time evolution equation for the single particle distribution function derived from the N-particle distribution function (A. Muriel, M. Dresden, Physica D 101 (1997) 297), an exact solution for the 3D Navier–Stokes equation – an old problem – has been found (A. Muriel, Results Phys. 1 (2011) 2). In this Letter, a second exact conclusion from the above-mentioned work is presented. We analyze the time symmetry properties of a formal, exact solution for the single-particle distribution function contracted from the many-body Liouville equation. This analysis must be done because group theoretic results on time reversal symmetry of the full Liouville equation (E.C.G. Sudarshan, N. Mukunda, Classical Mechanics: A Modern Perspective, Wiley, 1974). no longer applies automatically to the single particle distribution function contracted from the formal solution of the N-body Liouville equation. We find the following result: if the initial momentum distribution is even in the momentum, the single particle distribution is reversible. If there is any asymmetry in the initial momentum distribution, no matter how small, the system is irreversible.

  17. Distribution function approach to irreversible adsorption of interacting colloidal particles

    Science.gov (United States)

    Faraudo, Jordi; Bafaluy, Javier

    2000-01-01

    A statistical-mechanical description of the irreversible adsorption of interacting colloidal particles is developed. Our approach describes in a consistent way the interaction of particles from the bulk with adsorbed particles during the transport process towards the adsorbing surface. The macroscopic physical quantities corresponding to the actual process are expressed as averages over simpler auxiliary processes which proceed in the presence of a fixed number n of adsorbed particles. The adsorption rate verifies a generalized Langmuir equation, in which the kinetic resistance (the inverse of the kinetic coefficient) is expressed as the sum of a diffusional resistance and a resistance due to interaction with adsorbed particles during the transport process (blocking effect). Contrary to previous approaches, the blocking effect is not due to geometrical exclusion, instead it measures how the transport from the bulk is affected by the adsorbed particles. From the general expressions obtained, we have derived coverage expansions for the adsorption rate and the surface correlation function. The theory is applied to the case of colloidal particles interacting through DLVO potentials. This form of the kinetic coefficient is shown to be in agreement with recent experimental results, in which RSA fails.

  18. Irreversible gravitational collapse: black stars or black holes?

    CERN Document Server

    Corda, Christian

    2011-01-01

    It is well known that the concept of black hole has been considered very fascinating by scientists even before the introduction of Einstein's general relativity. They should be the final result of an irreversible gravitational collapse of very massive bodies. However, an unsolved problem concerning such objects is the presence of a space-time singularity in their core. Such a problem was present starting by the first historical papers concerning black holes. It is a common opinion that this problem could be solved when a correct quantum gravity theory will be, finally, constructed. In this work we review a way to remove black hole singularities at a classical level i.e. without arguments of quantum gravity. By using a particular non-linear electrodynamics Lagrangian, an exact solution of Einstein field equations is shown. The solution prevents the collapsing object to reach the gravitational radius, thus the final result becomes a black star, i.e. an astrophysical object where both of singularities and event ...

  19. Scaling Law for Irreversible Entropy Production in Critical Systems

    Science.gov (United States)

    Hoang, Danh-Tai; Prasanna Venkatesh, B.; Han, Seungju; Jo, Junghyo; Watanabe, Gentaro; Choi, Mahn-Soo

    2016-06-01

    We examine the Jarzynski equality for a quenching process across the critical point of second-order phase transitions, where absolute irreversibility and the effect of finite-sampling of the initial equilibrium distribution arise in a single setup with equal significance. We consider the Ising model as a prototypical example for spontaneous symmetry breaking and take into account the finite sampling issue by introducing a tolerance parameter. The initially ordered spins become disordered by quenching the ferromagnetic coupling constant. For a sudden quench, the deviation from the Jarzynski equality evaluated from the ideal ensemble average could, in principle, depend on the reduced coupling constant ε0 of the initial state and the system size L. We find that, instead of depending on ε0 and L separately, this deviation exhibits a scaling behavior through a universal combination of ε0 and L for a given tolerance parameter, inherited from the critical scaling laws of second-order phase transitions. A similar scaling law can be obtained for the finite-speed quench as well within the Kibble-Zurek mechanism.

  20. Fuel starvation. Irreversible degradation mechanisms in PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Rangel, Carmen M.; Silva, R.A.; Travassos, M.A.; Paiva, T.I.; Fernandes, V.R. [LNEG, National Laboratory for Energy and Geology, Lisboa (Portugal). UPCH Fuel Cells and Hydrogen Unit

    2010-07-01

    PEM fuel cell operates under very aggressive conditions in both anode and cathode. Failure modes and mechanism in PEM fuel cells include those related to thermal, chemical or mechanical issues that may constrain stability, power and lifetime. In this work, the case of fuel starvation is examined. The anode potential may rise to levels compatible with the oxidization of water. If water is not available, oxidation of the carbon support will accelerate catalyst sintering. Diagnostics methods used for in-situ and ex-situ analysis of PEM fuel cells are selected in order to better categorize irreversible changes of the cell. Electrochemical Impedance Spectroscopy (EIS) is found instrumental in the identification of fuel cell flooding conditions and membrane dehydration associated to mass transport limitations / reactant starvation and protonic conductivity decrease, respectively. Furthermore, it indicates that water electrolysis might happen at the anode. Cross sections of the membrane catalyst and gas diffusion layers examined by scanning electron microscopy indicate electrode thickness reduction as a result of reactions taking place during hydrogen starvation. Catalyst particles are found to migrate outwards and located on carbon backings. Membrane degradation in fuel cell environment is analyzed in terms of the mechanism for fluoride release which is considered an early predictor of membrane degradation. (orig.)

  1. The nineteenth century conflict between mechanism and irreversibility

    Science.gov (United States)

    van Strien, Marij

    2013-08-01

    The reversibility problem (better known as the reversibility objection) is usually taken to be an internal problem in the kinetic theory of gases, namely the problem of how to account for the second law of thermodynamics within this theory. Historically, it is seen as an objection that was raised against Boltzmann's kinetic theory of gases, which led Boltzmann to a statistical approach to the kinetic theory, culminating in the development of statistical mechanics. In this paper, I show that in the late nineteenth century, the reversibility problem had a much broader significance-it was widely discussed and certainly not only as an objection to Boltzmann's kinetic theory of gases. In this period, there was a conflict between mechanism and irreversibility in physics which was tied up with central issues in philosophy of science such as materialism, empiricism and the need for mechanistic foundations of physical theories, as well as with concerns about the heat death of the universe. I discuss how this conflict was handled by the major physicists of the period, such as Maxwell, Kelvin, Duhem, Poincaré, Mach and Planck, as well as by a number of lesser-known authors.

  2. Road deicing salt irreversibly disrupts osmoregulation of salamander egg clutches

    Energy Technology Data Exchange (ETDEWEB)

    Karraker, Nancy E., E-mail: karraker@hku.hk [Department of Environmental and Forest Biology, State University of New York, College of Environmental Science and Forestry, Syracuse, NY 13210 (United States); Gibbs, James P. [Department of Environmental and Forest Biology, State University of New York, College of Environmental Science and Forestry, Syracuse, NY 13210 (United States)

    2011-03-15

    It has been postulated that road deicing salts are sufficiently diluted by spring rains to ameliorate any physiological impacts to amphibians breeding in wetlands near roads. We tested this conjecture by exposing clutches of the spotted salamander (Ambystoma maculatum) to three chloride concentrations (1 mg/L, 145 mg/L, 945 mg/L) for nine days, then transferred clutches to control water for nine days, and measured change in mass at three-day intervals. We measured mass change because water uptake by clutches reduces risks to embryos associated with freezing, predation, and disease. Clutches in controls sequestered water asymptotically. Those in the moderate concentrations lost 18% mass initially and regained 14% after transfer to control water. Clutches in high concentration lost 33% mass and then lost an additional 8% after transfer. Our results suggest that spring rains do not ameliorate the effects of deicing salts in wetlands with extremely high chloride concentrations. - Road deicing salts irreversibly disrupts osmoregulation of salamander egg clutches.

  3. Parametric optimum design of an irreversible spin quantum refrigeration cycle

    Institute of Scientific and Technical Information of China (English)

    Lin Bi-Hong; Chen Jin-Can

    2005-01-01

    The general performance characteristics of an irreversible quantum refrigeration cycle using many non-interacting spin-1/2 systems as the working substance and consisting of two adiabatic and two isomagnetic field processes are investigated, based on the quantum master equation and semi-group approach. Expressions for several important performance parameters such as the coefficient of performance, cooling rate and power input are derived. By using numerical solutions, the cooling rate of the refrigeration cycle subject to the finite cycle duration is optimized. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal region of the coefficient of performance and the optimal ranges of the temperatures of the working substance and the times spent on the two isomagnetic field processes are determined. Moreover, the optimal performance of the cycle in the high-temperature limit is also analysed in detail. The results obtained here are further generalized, so that they may be directly used to describe the performance of the quantum refrigeration cycle using spin-J systems as the working substance.

  4. Scaling Law for Irreversible Entropy Production in Critical Systems

    Science.gov (United States)

    Hoang, Danh-Tai; Prasanna Venkatesh, B.; Han, Seungju; Jo, Junghyo; Watanabe, Gentaro; Choi, Mahn-Soo

    2016-01-01

    We examine the Jarzynski equality for a quenching process across the critical point of second-order phase transitions, where absolute irreversibility and the effect of finite-sampling of the initial equilibrium distribution arise in a single setup with equal significance. We consider the Ising model as a prototypical example for spontaneous symmetry breaking and take into account the finite sampling issue by introducing a tolerance parameter. The initially ordered spins become disordered by quenching the ferromagnetic coupling constant. For a sudden quench, the deviation from the Jarzynski equality evaluated from the ideal ensemble average could, in principle, depend on the reduced coupling constant ε0 of the initial state and the system size L. We find that, instead of depending on ε0 and L separately, this deviation exhibits a scaling behavior through a universal combination of ε0 and L for a given tolerance parameter, inherited from the critical scaling laws of second-order phase transitions. A similar scaling law can be obtained for the finite-speed quench as well within the Kibble-Zurek mechanism. PMID:27277558

  5. Eutectic solidification as explained by the thermodynamics of irreversible processes

    Directory of Open Access Journals (Sweden)

    W. Wołczyński

    2009-01-01

    Full Text Available The grain size diameter is the main parameter characterizing a given metallic alloy. In the case of Al-Si or Fe-C eutectic alloy theaverage inter-lamellar spacing is a good parameter which seems to be adequate to describe this irregular structure. To define the averageinter-lamellar spacing the regular areas within generally irregular structure has been distinguished.It has been postulated that the formation of regular structure could be related to the minimum entropy production criterion. From theother side the maximum destabilization of the non-faceted phase interface could be referred to marginal stability.The criterion of minimum entropy production allows to formulate the growth law for regular lamellar structure solidifying understationary state. It defines the regular eutectic spacing versus growth rate. The marginal stability concept allows to define the maximum wavelength which can be developed at the solid / liquid interface of non-faceted (Al phase. It defines the maximum spacing within irregular structure taking into account the wavelength of instability (marginal stability created at the non-faceted phase interface.An average inter-lamellar spacing results from the relationship formulated on the basis of both spacings. It should beemphasized that both conditions (criteria are deduced from the thermodynamics of irreversible processes.The simplified scheme of irregular structure incorporates, additionally the intermediate lamella of faceted phase that is also taken into account in the definition of average inter-lamellar spacing,

  6. Irreversible electroporation of human primary uveal melanoma in enucleated eyes.

    Directory of Open Access Journals (Sweden)

    Yossi Mandel

    Full Text Available Uveal melanoma (UM is the most common primary intraocular tumor in adults and is characterized by high rates of metastatic disease. Although brachytherapy is the most common globe-sparing treatment option for small- and medium-sized tumors, the treatment is associated with severe adverse reactions and does not lead to increased survival rates as compared to enucleation. The use of irreversible electroporation (IRE for tumor ablation has potential advantages in the treatment of tumors in complex organs such as the eye. Following previous theoretical work, herein we evaluate the use of IRE for uveal tumor ablation in human ex vivo eye model. Enucleated eyes of patients with uveal melanoma were treated with short electric pulses (50-100 µs, 1000-2000 V/cm using a customized electrode design. Tumor bioimpedance was measured before and after treatment and was followed by histopathological evaluation. We found that IRE caused tumor ablation characterized by cell membrane disruption while sparing the non-cellular sclera. Membrane disruption and loss of cellular capacitance were also associated with significant reduction in total tumor impedance and loss of impedance frequency dependence. The effect was more pronounced near the pulsing electrodes and was dependent on time from treatment to fixation. Future studies should further evaluate the potential of IRE as an alternative method of uveal melanoma treatment.

  7. The effects of irreversible electroporation (IRE on nerves.

    Directory of Open Access Journals (Sweden)

    Wei Li

    Full Text Available BACKGROUND: If a critical nerve is circumferentially involved with tumor, radical surgery intended to cure the cancer must sacrifice the nerve. Loss of critical nerves may lead to serious consequences. In spite of the impressive technical advancements in nerve reconstruction, complete recovery and normalization of nerve function is difficult to achieve. Though irreversible electroporation (IRE might be a promising choice to treat tumors near or involved critical nerve, the pathophysiology of the nerve after IRE treatment has not be clearly defined. METHODS: We applied IRE directly to a rat sciatic nerve to study the long term effects of IRE on the nerve. A sequence of 10 square pulses of 3800 V/cm, each 100 µs long was applied directly to rat sciatic nerves. In each animal of group I (IRE the procedure was applied to produce a treated length of about 10 mm. In each animal of group II (Control the electrodes were only applied directly on the sciatic nerve for the same time. Electrophysiological, histological, and functional studies were performed on immediately after and 3 days, 1 week, 3, 5, 7 and 10 weeks following surgery. FINDINGS: Electrophysiological, histological, and functional results show the nerve treated with IRE can attain full recovery after 7 weeks. CONCLUSION: This finding is indicative of the preservation of nerve involving malignant tumors with respect to the application of IRE pulses to ablate tumors completely. In summary, IRE may be a promising treatment tool for any tumor involving nerves.

  8. The Influence of Swirl Angle on the Irreversibilities in Turbulent Diffusion Flames

    Directory of Open Access Journals (Sweden)

    Alexandru Dobrovicescu

    2007-12-01

    Full Text Available The objective of this paper is to investigate the volumetric irreversibilities of turbulent swirling diffusion flames. The theoretical background of analysis relies on the local transport exergy equation, which allows the formulation of the well-known Gouy-Stodola theorem at the continuum level. It is already known that, in the case of turbulent flame, the chemical, thermal and mass diffusion irreversibilities represent in order of enumeration the predominant sources of exergy destruction. But these irreversibilities have a more complicated structure than in the laminar flames because the turbulent fluctuations generate new and important irreversibility sources, strongly influencing all the mechanisms mentioned above. Using numerical techniques for flow and multi-species balance equations, this paper tries to emphasize the role of both, swirling number and turbulent intensity field, not only in the burning process intensification but also in the irreversibility creation.

  9. Hematopoiesis stimulation test by interleukin 1{alpha} gene transfer in the Cynomolgus macaque: application to secondary medullary aplasia from an accidental irradiation; Essais de stimulation de l'hematopoiese par le transfert de gene de l'interleukine-1{alpha} chez le macaque cynomolgus: application a l'aplasie medullaire secondaire a une irradiation accidentelle

    Energy Technology Data Exchange (ETDEWEB)

    De Revel, Th.

    2002-12-15

    After a description of the context of medullary aplasia (haematological radiobiology, radiation acute syndrome, therapeutic care), and an overview of knowledge about the interleukin-1 and medullary stroma cells, this research thesis aims at investigating therapeutic alternatives for radio-accidental aplasia. More precisely, it aims at defining means to get cytokines which are efficient for haematopoiesis. Interleukin-1 is chosen for its properties and tests are performed on a macaque with two approaches for gene transfer: an ex vivo transfer by retroviral vector enabling an integration in the target cell genome, and an in situ transfer by adeno-viral vector directly applied in the animal osseous medulla

  10. Celulitis por citomegalovirus

    Directory of Open Access Journals (Sweden)

    A. Ruiz Lascano

    2002-12-01

    Full Text Available Las lesiones cutáneas por citomegalovirus (CMV son infrecuentes y a menudo una manifestación tardía de una enfermedad sistémica, que generalmente anuncia un curso fatal. Comunicamos un caso de celulitis por CMV: una mujer de 70 años con trasplante renal efectuado 1 mes antes de la consulta, terapia inmunosupresora con ciclosporina A y metilprednisona. La paciente ingresó por fiebre, dolor e impotencia funcional en pierna derecha. Comprobamos la existencia de una placa de 8 por 4 cm eritematoedematosa. La tratamos con antibióticos sin mejoría, por lo que realizamos un estudio histopatológico de piel que mostró cambios citopáticos compatibles con infección por CMV. Los cultivos bacteriológicos y micológicos fueron negativos. La inmunohistoquímica específica para CMV y el estudio de reacción en cadena de la polimerasa (PCR de la biopsia de piel fueron positivas, al igual que la antigenemia. El tratamiento con ganciclovir produjo la mejoría del cuadro clínico. En la literatura revisada no hemos encontrado la celulitis como manifestación de enfermedad cutánea por CMV.

  11. Immunologic response to tumor ablation with irreversible electroporation.

    Directory of Open Access Journals (Sweden)

    Xiaoxiang Li

    Full Text Available BACKGROUND: Irreversible electroporation (IRE is a promising technique for the focal treatment of pathologic tissues, which involves placing minimally invasive electrodes within the targeted region. However, the knowledge about the therapeutic efficacy and immune reactions in response to IRE remains in its infancy. METHODS: In this work, to detect whether tumor ablation with IRE could trigger the immunologic response, we developed an osteosarcoma rat model and applied IRE directly to ablate the tumor. In the experiment, 118 SD rats were randomized into 4 groups: the control, sham operation, surgical resection, and IRE groups. Another 28 rats without tumor cell implantation served as the normal non-tumor-bearing group. We analyzed the changes in T lymphocyte subsets, sIL-2R and IL-10 levels in the peripheral blood one day before operation, as well as at 1, 3, 7,14 and 21 days after the operation. Moreover, splenocytes were assayed for IFN-γ and IL-4 production using intracellular cytokine staining one day before the operation, as well as at 7 and 21 days after operation. RESULTS: We found that direct IRE completely ablated the tumor cells. A significant increase in peripheral lymphocytes, especially CD3(+ and CD4(+ cells, as well as an increased ratio of CD4(+/CD8(+ were detectable 7 days after operation in both the IRE and surgical resection groups. Compared with the surgical resection group, the IRE group exhibited a stronger cellular immune response. The sIL-2R level of the peripheral blood in the IRE group decreased with time and was significantly different from that in the surgical resection group. Moreover, ablation with IRE significantly increased the percentage of IFN-γ-positive splenocytes. CONCLUSION: These findings indicated that IRE could not only locally destroy the tumor but also change the status of cellular immunity in osteosarcoma-bearing rats. This provides experimental evidence for the clinical application of IRE in

  12. Irreversible collective migration of cyanobacteria in eutrophic conditions.

    Directory of Open Access Journals (Sweden)

    Julien Dervaux

    Full Text Available In response to natural or anthropocentric pollutions coupled to global climate changes, microorganisms from aquatic environments can suddenly accumulate on water surface. These dense suspensions, known as blooms, are harmful to ecosystems and significantly degrade the quality of water resources. In order to determine the physico-chemical parameters involved in their formation and quantitatively predict their appearance, we successfully reproduced irreversible cyanobacterial blooms in vitro. By combining chemical, biochemical and hydrodynamic evidences, we identify a mechanism, unrelated to the presence of internal gas vesicles, allowing the sudden collective upward migration in test tubes of several cyanobacterial strains (Microcystis aeruginosa PCC 7005, Microcystis aeruginosa PCC 7806 and Synechocystis sp. PCC 6803. The final state consists in a foamy layer of biomass at the air-liquid interface, in which micro-organisms remain alive for weeks, the medium lying below being almost completely depleted of cyanobacteria. These "laboratory blooms" start with the aggregation of cells at high ionic force in cyanobacterial strains that produce anionic extracellular polymeric substances (EPS. Under appropriate conditions of nutrients and light intensity, the high photosynthetic activity within cell clusters leads the dissolved oxygen (DO to supersaturate and to nucleate into bubbles. Trapped within the EPS, these bubbles grow until their buoyancy pulls the biomass towards the free surface. By investigating a wide range of spatially homogeneous environmental conditions (illumination, salinity, cell and nutrient concentration we identify species-dependent thresholds and timescales for bloom formation. We conclude on the relevance of such results for cyanobacterial bloom formation in the environment and we propose an efficient method for biomass harvesting in bioreactors.

  13. Multiscale time irreversibility of heart rate and blood pressure variability during orthostasis

    International Nuclear Information System (INIS)

    Time irreversibility is a characteristic feature of non-equilibrium, complex systems such as the cardiovascular control mediated by the autonomic nervous system (ANS). Time irreversibility analysis of heart rate variability (HRV) and blood pressure variability (BPV) represents a new approach to assess cardiovascular regulatory mechanisms. The aim of this paper was to assess the changes in HRV and BPV irreversibility during the active orthostatic test (a balance of ANS shifted towards sympathetic predominance) in 28 healthy young subjects. We used three different time irreversibility indices—Porta’s, Guzik's and Ehler's indices (P%, G% and E, respectively) derived from data segments containing 1000 beat-to-beat intervals on four timescales. We observed an increase in the HRV and a decrease in the BPV irreversibility during standing compared to the supine position. The postural change in irreversibility was confirmed by surrogate data analysis. The differences were more evident in G% and E than P% and for higher scale factors. Statistical analysis showed a close relationship between G% and E. Contrary to this, the association between P% and G% and P% and E was not proven. We conclude that time irreversibility of beat-to-beat HRV and BPV is significantly altered during orthostasis, implicating involvement of the autonomous nervous system in its generation. (paper)

  14. Fundamental optimal relation of a generalized irreversible Carnot heat pump with complex heat transfer law

    Indian Academy of Sciences (India)

    Jun Li; Lingen Chen; Fengrui Sun

    2010-02-01

    The fundamental optimal relation between heating load and coefficient of performance (COP) of a generalized irreversible Carnot heat pump is derived based on a new generalized heat transfer law, which includes the generalized convective heat transfer law and generalized radiative heat transfer law, $q \\varpropto ( T^{n})^{m}$. The generalized irreversible Carnot heat pump model incorporates several internal and external irreversibilities, such as heat resistance, bypass heat leakage, friction, turbulence and other undesirable irreversibility factors. The added irreversibilities besides heat resistance are characterized by a constant parameter and a constant coefficient. The effects of heat transfer laws and various loss terms are analysed. The heating load vs. COP characteristic of a generalized irreversible Carnot heat pump is a parabolic-like curve, which is consistent with the experimental result of thermoelectric heat pump. The obtained results include those obtained in many literatures and indicated that the analysis results of the generalized irreversible Carnot heat pump were more suitable for engineering practice than those of the endoreversible Carnot heat pump.

  15. PANCITOPENIA EN UN CANINO OCASIONADA POR LA ADMINISTRACIÓN DE ESTROGENOS PARA EVITAR UNA PREÑEZ NO DESEADA

    Directory of Open Access Journals (Sweden)

    Diego Echeverri.

    2007-12-01

    Full Text Available Objetivo. Presentar el caso clínico de una paciente canina pancitopenica debido al uso indebido de estrógenos como método anticonceptivo. Materiales y métodos. Paciente canina de raza Poodle de 8 años, la cual fue llevada a consulta por presentar decaimiento, inapetencia, hemorragias petequiales e hipema. Resultado. Una vez realizada la anamnesis, el examen físico y los exámenes paraclínicos así como la evolución del cuadro clínico se demostró la intoxicación estrogénica exógena como diagnóstico definitivo. Conclusiones. El uso de estrógenos como método para la terminación de preñez en perras no está recomendado o considerado ético para muchos autores o asociaciones veterinarias por varias razones como: una dosis de estrógenos aparentemente efectiva no se ha establecido, por lo que su administración puede resultar en enfermedad uterina; dosis de estrógenos aparentemente seguras fueron determinadas como inseguras, y dosis aparentemente efectivas produjeron enfermedad uterina. La aplasia medular es un resultado común de la intoxicación estrogénica y esta puede conducir incluso a la muerte del paciente.

  16. Measurement of Anti-Erythropoiesis-Stimulating Agent IgG4 Antibody as an Indicator of Antibody-Mediated Pure Red Cell Aplasia

    Science.gov (United States)

    Weeraratne, Dohan K.; Kuck, Andrew J.; Chirmule, Narendra

    2013-01-01

    Patients treated with erythropoietin-based erythropoiesis-stimulating agents (ESAs) can develop a rare but life-threatening condition called antibody-mediated pure red cell aplasia (amPRCA). The antibody characteristics in a nephrology patient with amPRCA include high antibody concentrations with neutralizing activity and a mixed IgG subclass including anti-ESA IgG4 antibodies. In contrast, anti-ESA IgG4 antibody is generally not detected in baseline samples and antibody-positive non-PRCA patients. Therefore, we validated a highly sensitive immunoassay on the ImmunoCAP 100 instrument to quantitate anti-ESA IgG4 antibodies using a human recombinant anti-epoetin alfa (EPO) IgG4 antibody as a calibrator. The biotinylated ESA was applied to a streptavidin ImmunoCAP, and bound anti-ESA IgG4 antibodies were detected using a β-galactosidase-conjugated mouse anti-human IgG4 antibody. The validated assay was used to detect anti-ESA IgG4 in amPRCA and non-PRCA patients. The immunoassay detected 15 ng/ml of human anti-EPO IgG4 antibody in the presence of a 200 M excess of human anti-ESA IgG1, IgG2, or IgM antibody and tolerated 2 μg/ml of soluble erythropoietin. All patient samples with confirmed amPRCA had measurable anti-ESA IgG4 antibodies. In addition, 94% (17/18) of non-PRCA patient samples were antibody negative or had below 15 ng/ml of anti-ESA IgG4 antibodies. This novel immunoassay can measure low-nanogram quantities of human anti-ESA IgG4 antibodies in the presence of other anti-ESA antibodies. An increased concentration of anti-ESA IgG4 antibody is associated with the development of amPRCA. We propose that the measurement of anti-ESA specific IgG4 antibodies may facilitate early detection of amPRCA in patients receiving all ESAs structurally related to human erythropoietin. PMID:23114696

  17. A Fingerprint Encryption Scheme Based on Irreversible Function and Secure Authentication

    Science.gov (United States)

    Yu, Jianping; Zhang, Peng; Wang, Shulan

    2015-01-01

    A fingerprint encryption scheme based on irreversible function has been designed in this paper. Since the fingerprint template includes almost the entire information of users' fingerprints, the personal authentication can be determined only by the fingerprint features. This paper proposes an irreversible transforming function (using the improved SHA1 algorithm) to transform the original minutiae which are extracted from the thinned fingerprint image. Then, Chinese remainder theorem is used to obtain the biokey from the integration of the transformed minutiae and the private key. The result shows that the scheme has better performance on security and efficiency comparing with other irreversible function schemes. PMID:25873989

  18. A Fingerprint Encryption Scheme Based on Irreversible Function and Secure Authentication

    Directory of Open Access Journals (Sweden)

    Yijun Yang

    2015-01-01

    Full Text Available A fingerprint encryption scheme based on irreversible function has been designed in this paper. Since the fingerprint template includes almost the entire information of users’ fingerprints, the personal authentication can be determined only by the fingerprint features. This paper proposes an irreversible transforming function (using the improved SHA1 algorithm to transform the original minutiae which are extracted from the thinned fingerprint image. Then, Chinese remainder theorem is used to obtain the biokey from the integration of the transformed minutiae and the private key. The result shows that the scheme has better performance on security and efficiency comparing with other irreversible function schemes.

  19. A fingerprint encryption scheme based on irreversible function and secure authentication.

    Science.gov (United States)

    Yang, Yijun; Yu, Jianping; Zhang, Peng; Wang, Shulan

    2015-01-01

    A fingerprint encryption scheme based on irreversible function has been designed in this paper. Since the fingerprint template includes almost the entire information of users' fingerprints, the personal authentication can be determined only by the fingerprint features. This paper proposes an irreversible transforming function (using the improved SHA1 algorithm) to transform the original minutiae which are extracted from the thinned fingerprint image. Then, Chinese remainder theorem is used to obtain the biokey from the integration of the transformed minutiae and the private key. The result shows that the scheme has better performance on security and efficiency comparing with other irreversible function schemes. PMID:25873989

  20. The Effects of Internal and External Irreversibility of a Vapor Compression Refrigeration Cycle

    Science.gov (United States)

    Wang, Fu-Jen; Chiou, Jeng-Shing

    The concept of finite-time thermodynamics is employed to investigate the optimal refrigeration rate for an irreversible refrigeration cycle. The heat transfer between the system (internal) fluid and cooling (external) fluid takes place at the actual heat exchanger, which has the finite-size heat transfer area and the realistic heat transfer effectiveness. The internal irreversibility results from the compression process and the expansion process are also considered. The optimal refrigeration rate is calculated and expressed in terms of the irreversibility parameter (Ir), coefficient of performance (COP), the time ratio(γ) of heat transfer processes and the effectiveness of heat exchanger. The derived COP which consider both the external and internal irreversibility can thus be considered as the benchmark value for a practical refrigeration cycle, and the parametric study can provide the basis for both determination of optimal operating conditions and design of a practical refrigeration cycle.

  1. Cooling load and COP optimization of an irreversible Carnot refrigerator with spin-1/2 systems

    Directory of Open Access Journals (Sweden)

    Xiaowei Liu, Lingen Chen, Feng Wu, Fengrui Sun

    2011-09-01

    Full Text Available A model of an irreversible quantum refrigerator with working medium consisting of many non-interacting spin-1/2 systems is established in this paper. The quantum refrigeration cycle is composed of two isothermal processes and two irreversible adiabatic processes and is referred to as a spin quantum Carnot refrigeration cycle. Expressions of some important performance parameters, such as cycle period, cooling load and coefficient of performance (COP for the irreversible spin quantum Carnot refrigerator are derived, and detailed numerical examples are provided. The optimal performance of the quantum refrigerator at high temperature limit is analyzed with numerical examples. Effects of internal irreversibility and heat leakage on the performance are discussed in detail. The endoreversible case, frictionless case and the case without heat leakage are discussed in brief.

  2. Treatise on irreversible and statistical thermodynamics an introduction to nonclassical thermodynamics

    CERN Document Server

    Yourgrau, Wolfgang; Raw, Gough

    2002-01-01

    Extensively revised edition of a much-respected work examines thermodynamics of irreversible processes, general principles of statistical thermodynamics, assemblies of noninteracting structureless particles, and statistical theory. 1966 edition.

  3. The maximum coefficient of performance of internally irreversible refrigerators and heat pumps

    Science.gov (United States)

    Ait-Ali, Mohand A.

    1996-04-01

    A class of irreversible refrigeration cycles is investigated to determine the maximum coefficient of performance in the heat pump mode and the refrigerator mode. For the purpose of generality and simplicity of the results, finite-time heat transfer in the condenser and evaporator is expressed in terms of arithmetic mean temperature differences. The generic source of internal irreversibility is measured by a single irreversibility factor which transforms the Clausius inequality into an equality to simplify the cycle model. These optimum cycle performances are obtained as closed form analytical expressions in which the irreversibility factor has been shown to be simply related to the ratio of the actual and endoreversible cycle coefficients of performance.

  4. Thermodynamic efficiency of the cardiac cycle and irreversibility in the interbeat interval time series

    OpenAIRE

    Alejandro Muñoz-Diosdado; Gonzalo Gálvez-Coyt; Alejandro Alonso Martínez

    2010-01-01

    Cardiac cycle can be analyzed as a thermodynamic cycle, however, the inherent variability of this cycle implies that, although in the short term the cycle is quasi-reversible, in the long term is irreversible. This work discusses two important aspects of the cardiac cycle related with thermodynamic concepts: the calculation of the cycles efficiency and the quantification of the irreversibility of interbeat interval time series. The results show that there is a variability of cardiac eff...

  5. Timescales and Frequencies of Reversible and Irreversible Adhesion Events of Single Bacterial Cells.

    Science.gov (United States)

    Hoffman, Michelle D; Zucker, Lauren I; Brown, Pamela J B; Kysela, David T; Brun, Yves V; Jacobson, Stephen C

    2015-12-15

    In the environment, most bacteria form surface-attached cell communities called biofilms. The attachment of single cells to surfaces involves an initial reversible stage typically mediated by surface structures such as flagella and pili, followed by a permanent adhesion stage usually mediated by polysaccharide adhesives. Here, we determine the absolute and relative timescales and frequencies of reversible and irreversible adhesion of single cells of the bacterium Caulobacter crescentus to a glass surface in a microfluidic device. We used fluorescence microscopy of C. crescentus expressing green fluorescent protein to track the swimming behavior of individual cells prior to adhesion, monitor the cell at the surface, and determine whether the cell reversibly or irreversibly adhered to the surface. A fluorescently labeled lectin that binds specifically to polar polysaccharides, termed holdfast, discriminated irreversible adhesion events from reversible adhesion events where no holdfast formed. In wild-type cells, the holdfast production time for irreversible adhesion events initiated by surface contact (23 s) was 30-times faster than the holdfast production time that occurs through developmental regulation (13 min). Irreversible adhesion events in wild-type cells (3.3 events/min) are 15-times more frequent than in pilus-minus mutant cells (0.2 events/min), indicating the pili are critical structures in the transition from reversible to irreversible surface-stimulated adhesion. In reversible adhesion events, the dwell time of cells at the surface before departing was the same for wild-type cells (12 s) and pilus-minus mutant cells (13 s), suggesting the pili do not play a significant role in reversible adhesion. Moreover, reversible adhesion events in wild-type cells (6.8 events/min) occur twice as frequently as irreversible adhesion events (3.3 events/min), demonstrating that most cells contact the surface multiple times before transitioning from reversible to

  6. Irreversible Electroporation of a Hepatocellular Carcinoma Lesion Adjacent to a Transjugular Intrahepatic Portosystemic Shunt Stent Graft

    Energy Technology Data Exchange (ETDEWEB)

    Niessen, Christoph; Jung, Ernst Michael; Wohlgemuth, Walter A. [Department of Radiology, University Medical Center Regensburg, Regensburg D-93053 (Germany); Trabold, Benedikt [Department of Anaesthesia, University Medical Center Regensburg, Regensburg D-93053 (Germany); Haimerl, Michael; Schreyer, Andreas; Stroszczynski, Christian; Wiggermann, Philipp [Department of Radiology, University Medical Center Regensburg, Regensburg D-93053 (Germany)

    2013-07-01

    We report in a 65-year-old man hepatocellular carcinoma adjacent to a transjugular intrahepatic portosystemic shunt stent-graft which was successfully treated with irreversible electroporation (IRE). IRE is a new non-thermal tissue ablation technique which uses electrical pulses to induce cell necrosis by irreversible membrane poration. IRE proved to be more advantageous in the ablation of perivascular tumor with little injury to the surrounding structures.

  7. A review on thermodynamic optimization of irreversible refrigerator and verification with transcritical CO2 system

    OpenAIRE

    Sarkar, Jahar

    2014-01-01

    The transcritical vapor compression refrigeration cycle consists of isothermal heat addition process and isobaric non-isothermal heat rejection process with highly variable heat capacity unlike to the subcritical cycle. Hence, it is quite interesting whether the analysis and optimization results of irreversible Carnot-like refrigerator are applicable for this case. The present study consists of two parts: the detailed review on theoretical analysis and analytical optimizations of irreversible...

  8. A statistical model for multidimensional irreversible electroporation cell death in tissue

    OpenAIRE

    Rubinsky Boris; Golberg Alex

    2010-01-01

    Abstract Background Irreversible electroporation (IRE) is a minimally invasive tissue ablation technique which utilizes electric pulses delivered by electrodes to a targeted area of tissue to produce high amplitude electric fields, thus inducing irreversible damage to the cell membrane lipid bilayer. An important application of this technique is for cancer tissue ablation. Mathematical modelling is considered important in IRE treatment planning. In the past, IRE mathematical modelling used a ...

  9. Irreversible and reversible topoisomerase II DNA cleavage stimulated by clerocidin: sequence specificity and structural drug determinants.

    Science.gov (United States)

    Binaschi, M; Zagotto, G; Palumbo, M; Zunino, F; Farinosi, R; Capranico, G

    1997-05-01

    In contrast to other topoisomerase II poisons, the microbial terpenoid clerocidin was shown to stimulate irreversible topoisomerase II-mediated DNA cleavage. To establish the structural determinants for drug activity, in this study we have investigated intensity patterns and sequence specificity of clerocidin-stimulated DNA cleavage using 5'-end 32P-labeled DNA fragments. At a majority of the sites, clerocidin-stimulated cleavage did not revert upon NaCl addition; nevertheless, at some sites, cleavage completely reverted. Statistical analyses showed that drug-preferred bases were different in the two cases: guanine and cytosine were highly preferred at position -1 at irreversible and reversible sites, respectively. These results demonstrated that cleavage irreversibility was site selective and required a guanine at the 3' end of the cut. Further experiments revealed that some irreversible sites showed an abnormal electrophoretic mobility in sequencing gels with respect to cleaved bands generated by 4-(9-acridinylamino)methanesulfon-m-anisidide, suggesting a chemical alteration of the DNA strand. Interestingly, the ability to stimulate irreversible cleavage progressively decreased over time when clerocidin was stored in ethanol. Under these conditions, nuclear magnetic resonance measurements demonstrated that the drug underwent structural modifications that involved the C-12-C-15 side chain. Thus, the results indicate that a specific moiety of clerocidin may react with the DNA (guanine at -1) in the ternary complex, resulting in cleavage irreversibility and in altered DNA mobility in sequencing gels. PMID:9135013

  10. Osteomielitis por salmonella

    Directory of Open Access Journals (Sweden)

    Alicia Velázquez Pérez

    2014-08-01

    Full Text Available Se presenta el caso de una paciente femenina de color blanco y dos años de edad, con diagnóstico prenatal de sicklemia, que desde edades tempranas tiene problemas de la enfermedad. Ingresó en esta ocasión por una de las complicaciones infecciosas que ocasiona este padecimiento, una osteomielitis del húmero izquierdo, aislándose el germen en el hemocultivo realizado, una salmonella. Necesitó de tratamiento enérgico y prolongado; se obtuvo un resultado satisfactorio en la evolución de la enfermedad y se sigue sistemáticamente por consulta externa en la actualidad

  11. Dermatitis canina por Malassezia

    Directory of Open Access Journals (Sweden)

    Rejas López, Juan

    2008-05-01

    Full Text Available La dermatitis por Malassezia en perros en generalmente una complicación a procesos alérgicos, seborreicos, presencia de pliegues, etc. aunque también se han descrito otras presentaciones, como la hipersensibilidad contra esta levadura. La demostración de la presencia de Malassesia pachydermatis se hace de manera sencilla mediante citología. El tratamiento de esta dermatitis puede ser tópico u oral.

  12. Dermatitis canina por Malassezia

    OpenAIRE

    Rejas López, Juan

    2008-01-01

    La dermatitis por Malassezia en perros en generalmente una complicación a procesos alérgicos, seborreicos, presencia de pliegues, etc. aunque también se han descrito otras presentaciones, como la hipersensibilidad contra esta levadura. La demostración de la presencia de Malassesia pachydermatis se hace de manera sencilla mediante citología. El tratamiento de esta dermatitis puede ser tópico u oral.

  13. causada por Fusarium moniliforme

    Directory of Open Access Journals (Sweden)

    Mariano Mendoza Elos

    2006-01-01

    Full Text Available El objetivo de éste trabajo fue determinar la resistencia horizontal de 134 líneas S1 de maíz al hongo Fusarium moniliforme. La enfermedad fue inducida mediante inoculación en la etapa de floración masculina bajo condiciones de campo utilizando la técnica del palillo. Las líneas se evaluaron en México en 2002. La estimación de la enfermedad se hizo en dos ocasiones con una separación de 20 días. Las evaluaciones mostraron que las líneas Roque-801, 804, 1103 y 1405 fueron resistentes en la primera evaluación. Las tasas de incremento de la enfermedad variaron de 0,01 a 0,229 por unidad por día. Las líneas mostraron bajos niveles de enfermedad de 0 a 1 % en la primera evaluación. En la segunda evaluación, los niveles de enfermedad variaron de 49 a 100 %. En un programa de mejoramiento genético estas líneas pueden ser utilizadas para mejorar la resistencia horizontal del maíz a la pudrición del tallo causada por Fusarium moniliforme

  14. PREDICTION OF THE VALUE OF IRREVERSIBLE DEFORMATION OF ROAD STRUCTURE FROM THE IMPACT OF TRAFFIC

    Directory of Open Access Journals (Sweden)

    F. V. Matvienko

    2011-07-01

    Full Text Available Problem statement. The study of irreversible strains in areas of non-rigid pavement with asphalt coating under the influence of traffic flow requires development of methodologies for assessment of the operational status of asphalt concrete pavement subjected to the formation of ruts. To pre-dict the magnitude of irreversible deformation of the pavement, that is rut, mathematical model, methodology and instruments to measure the parameters of road construction should be developed.Results and conclusions. Measurements of the deflection of road construction and rut parameters, including wear and plastic deformation, proved the adequacy of the proposed mathematical model. Obtained analytical dependences allow prediction of pavement wear, plastic deformation and subgrade deterioration. In contrast to the known ones, they take into account the impact of traffic on the formation of a rut. Proposed methods allow estimation of irreversible pavement deformations based on the values obtained with the help of instruments.

  15. Maximum power, ecological function and efficiency of an irreversible Carnot cycle. A cost and effectiveness optimization

    CERN Document Server

    Aragon-Gonzalez, G; Leon-Galicia, A; Morales-Gomez, J R

    2007-01-01

    In this work we include, for the Carnot cycle, irreversibilities of linear finite rate of heat transferences between the heat engine and its reservoirs, heat leak between the reservoirs and internal dissipations of the working fluid. A first optimization of the power output, the efficiency and ecological function of an irreversible Carnot cycle, with respect to: internal temperature ratio, time ratio for the heat exchange and the allocation ratio of the heat exchangers; is performed. For the second and third optimizations, the optimum values for the time ratio and internal temperature ratio are substituted into the equation of power and, then, the optimizations with respect to the cost and effectiveness ratio of the heat exchangers are performed. Finally, a criterion of partial optimization for the class of irreversible Carnot engines is herein presented.

  16. EXERGY-BASED ECOLOGICAL ANALYSIS OF GENERALIZED IRREVERSIBLE HEAT PUMP SYSTEM

    Directory of Open Access Journals (Sweden)

    GOVIND MAHESHWARI

    2011-10-01

    Full Text Available A reverse Carnot cycle forms the basis of all heat-pump cycles in providing heating and cooling loads. The optimal exergy-based Ecological analysis of an irreversible Heat-pump system with the losses of heat resistance, heat leak and internal irreversibility has been carried out by taking into account Exergy based ecological function (E as an objective in the viewpoint of Finite-Time-Thermodynamics (FTT or Entropy Generation Minimization (EGM. Exergy is defined here as the power required minus the lost power. The effects of irreversibilities along with internal heat leakage on coefficient on the performance of the system are investigated. The exergy based Ecological function decreases steadily with irreversibilites and heat leakages in the system. COP in such a system increases with the cycle temperature ratio. If a heat pump cycle is optimized with above mentioned criterion, there is a trade-off between its coefficient of Performance and the heating load it provides.

  17. Optimal fundamental characteristic of a quantum harmonic oscillator Carnot refrigerator with multi-irreversibilities

    Directory of Open Access Journals (Sweden)

    Xiaowei Liu, Lingen Chen, Feng Wu, Fengrui Sun

    2015-01-01

    Full Text Available The optimal performance of an irreversible quantum Carnot refrigerator with working medium consisting of many non-interacting harmonic oscillators is investigated in this paper. The quantum refrigerator cycle is composed of two isothermal processes and two irreversible adiabatic processes, and the irreversibilities of heat resistance, internal friction and bypass heat leakage are considered. By using the quantum master equation, semi-group approach and finite time thermodynamics (FTT, this paper derives the cooling load and coefficient of performance (COP of the quantum refrigeration cycle and provides detailed numerical examples. At high temperature limit, the cooling load versus COP characteristic curves are plotted, and effects of internal friction and bypass heat leakage on the optimal performance of the quantum refrigerator are discussed. Three special cases, i.e., endoreversible, frictionless and without bypass heat leakage, are discussed in brief.

  18. Thermo-economic modeling and optimization of an irreversible solar-driven heat engine

    International Nuclear Information System (INIS)

    Highlights: • An irreversible solar-driven heat engine is optimized. • Developed multi objective evolutionary approaches is used. • Power output, ecological function and thermal efficiency are optimized. - Abstract: The present paper illustrates a new thermo-economic performance analysis of an irreversible solar-driven heat engine. Moreover, aforementioned irreversible solar-driven heat engine is optimized by employing thermo-economic functions. With the help of the first and second laws of thermodynamics, an equivalent system is initially specified. To assess this goal, three objective functions that the normalized objective function associated to the power output (FP) and Normalized ecological function (FE) and thermal efficiency (ηth) are involved in optimization process simultaneously. Three objective functions are maximized at the same time. A multi objective evolutionary approaches (MOEAs) on the basis of NSGA-II method is employed in this work

  19. Reconsideration of Criteria and Modeling in Order to Optimize the Efficiency of Irreversible Thermomechanical Heat Engines

    Directory of Open Access Journals (Sweden)

    Michel Feidt

    2010-12-01

    Full Text Available The purpose of this work is to precise and complete one recently proposed in the literature and relative to a general criterion to maximize the first law efficiency of irreversible heat engines. It is shown that the previous proposal seems to be a particular case. A new proposal has been developed for a Carnot irreversible thermomechanical heat engine at steady state associated to two infinite heat reservoirs (hot source, and cold sink: this constitutes the studied system. The presence of heat leak is accounted for, with the most simple form, as is done generally in the literature. Irreversibility is modeled through , created internal entropy rate in the converter (engine, and , total created entropy rate in the system. Heat transfer laws are represented as general functions of temperatures. These concepts are particularized to the most common heat transfer law (linear one. Consequences of the proposal are examined; some new analytical results are proposed for efficiencies.

  20. FINITE TIME THERMODYNAMIC MODELING AND ANALYSIS FOR AN IRREVERSIBLE ATKINSON CYCLE

    Directory of Open Access Journals (Sweden)

    Yanlin Ge

    2010-01-01

    Full Text Available Performance of an air-standard Atkinson cycle is analyzed by using finite-time thermodynamics. The irreversible cycle model which is more close to practice is founded. In this model, the non-linear relation between the specific heats of working fluid and its temperature, the friction loss computed according to the mean velocity of the piston, the internal irreversibility described by using the compression and expansion efficiencies, and heat transfer loss are considered. The relations between the power output and the compression ratio, between the thermal efficiency and the compression ratio, as well as the optimal relation between power output and the efficiency of the cycle are derived by detailed numerical examples. Moreover, the effects of internal irreversibility, heat transfer loss and friction loss on the cycle performance are analyzed. The results obtained in this paper may provide guidelines for the design of practical internal combustion engines.

  1. Irreversible models with Boltzmann–Gibbs probability distribution and entropy production

    International Nuclear Information System (INIS)

    We analyze irreversible interacting spin models evolving according to a master equation with spin flip transition rates that do not obey detailed balance but obey global balance with a Boltzmann–Gibbs probability distribution. Spin flip transition rates with up–down symmetry are obtained for a linear chain, a square lattice, and a cubic lattice with a stationary state corresponding to the Ising model with nearest neighbor interactions. We show that these irreversible dynamics describes the contact of the system with particle reservoirs that cause a flux of particles through the system. Using a microscopic definition, we determine the entropy production rate of these irreversible models and show that it can be written as a macroscopic bilinear form in the forces and fluxes. Exact expressions for this property are obtained for the linear chain and the square lattice. In this last case the entropy production rate displays a singularity at the phase transition point of the same type as the entropy itself

  2. Optimization of the performance characteristics in an irreversible regeneration magnetic Brayton refrigeration cycle

    Science.gov (United States)

    Wang, Hao; Wu, GuoXing

    2012-02-01

    A model of the irreversible regenerative Brayton refrigeration cycle working with paramagnetic materials is established, in which the regeneration problem in two constant-magnetic field processes and the irreversibility in two adiabatic processes are considered synthetically. Expressions for the COP, cooling rate, power input, the minimum ratio of the two magnetic fields, etc., are derived. It is found that the influence of the irreversibility and the regeneration on the main performance parameters of the magnetic Brayton refrigerator is remarkable. It is important that we have obtained several optimal criteria, which may provide some theoretical basis for the optimal design and operation of the Brayton refrigerator. The results obtained in the paper can provide some new theoretical information for the optimal design and performance improvement of real Brayton refrigerators.

  3. Miotoxicidade por organofosforados

    Directory of Open Access Journals (Sweden)

    Cavaliere Maria J.

    1996-01-01

    Full Text Available Os organofosforados são um grupo de compostos químicos amplamente utilizados em agropecuária como inseticidas, ocasionando intoxicações acidentais em animais e humanos, e mesmo sendo utilizados em tentativas de suicídio. A toxicidade desses produtos decorre sobretudo de insuficiência cárdio-respiratória por compromentimento do sistema nervoso autônomo. Sabe-se que alguns destes compostos induzem em animais de experimentação e em humanos, uma miopatia caracterizada por degeneração de células musculares, comprometendo sobretudo a musculatura respiratória. Baseado no fato de que este comprometimento contribui para a piora da função respiratória, propõe-se um protocolo de avaliação rotineira de miotoxicidade por compostos organofosforados, através de uma bateria mínima e suficiente de colorações e reações histoquímicas para quantificação da necrose muscular. Utilizaram-se como modelo experimental, grupos de ratos albinos (Wistar intoxicados com o organofosforado paraoxon, com e sem antídotos (atropina ou pralidoxima. Verificou-se nos grupos tratados com paraoxon e paraoxon mais atropina, necrose de fibras musculares no diafragma, que atingia em determinadas áreas até 15% das fibras. No grupo tratado com paraoxon mais pralidoxima, a necrose foi mínima, evidenciando o papel mioprotetor deste último antídoto.

  4. Por mil devaluados pesos

    Directory of Open Access Journals (Sweden)

    Annie Rodríguez Collázos

    2013-03-01

    Full Text Available El estudio de lo popular y lo urbano hasta ahora se ha centrado en el comportamiento y en algunas relaciones de los habitantes con su entorno. “Por mil devaluados pesos. Publicidad popular y urbana”, pretende explorar las formas de publicidad, dispersas en diferentes espacios populares y urbanos en Bogotá, identificando esquemas y formas características de sus propios códigos comunicativos; se centran en un objeto de estudio consistente en las estrategias publicitarias y los códigos comunicativos en los mensajes publicitarios populares en las subculturas de San Victorino, 7 de Agosto y Sanandresito de San José.

  5. The universal power and efficiency characteristics for irreversible reciprocating heat engine cycles

    CERN Document Server

    Qin Xiao Yong; Sun Feng Rui; Wu Chih

    2003-01-01

    The performance of irreversible reciprocating heat engine cycles with heat transfer loss and friction-like term loss is analysed using finite-time thermodynamics. The universal relations between the power output and the compression ratio, between the thermal efficiency and the compression ratio, and the optimal relation between power output and the efficiency of the cycles are derived. Moreover, analysis and optimization of the model were carried out in order to investigate the effect of cycle processes on the performance of the cycle using numerical examples. The results obtained herein include the performance characteristics of irreversible reciprocating Diesel, Otto, Atkinson and Brayton cycles.

  6. Percutaneous Irreversible Electroporation for Recurrent Thyroid Cancer--A Case Report.

    Science.gov (United States)

    Meijerink, Martijn R; Scheffer, Hester J; de Bree, Remco; Sedee, Robert-Jan

    2015-08-01

    A 74-year-old man presented with a small locoregional, histopathologically proven, fluorodeoxyglucose positron emission tomography/computed tomography-avid recurrence of follicular thyroid carcinoma in the left subglottic space after extensive surgical resection, adjuvant radioactive iodine therapy, and external beam radiation therapy. Because all established focal therapies were contraindicated, percutaneous irreversible electroporation was performed without complications. Follow-up imaging at 7 months showed a small ablation scar without signs for residual vital tumor tissue. Irreversible electroporation may be a viable treatment option for selected cases of recurring head and neck tumors that are unsuitable for other local treatments. PMID:26210244

  7. Ecological performance of a generalized irreversible Carnot heat engine with complex heat transfer law

    Directory of Open Access Journals (Sweden)

    Jun Li, Lingen Chen, Fengrui Sun

    2011-01-01

    Full Text Available The optimal ecological performance of a generalized irreversible Carnot heat engine with the losses of heat-resistance, heat leakage and internal irreversibility, in which the transfer between the working fluid and the heat reservoirs obeys a complex heat transfer law, including generalized convective heat transfer law and generalized radiative heat transfer law is derived by taking an ecological optimization criterion as the objective, which consists of maximizing a function representing the best compromise between the power and entropy production rate of the heat engine. The effects of heat transfer laws and various loss terms are analyzed. The obtained results include those obtained in many literatures.

  8. Irreversibility and the Arrow of Time in a Quenched Quantum System.

    Science.gov (United States)

    Batalhão, T B; Souza, A M; Sarthour, R S; Oliveira, I S; Paternostro, M; Lutz, E; Serra, R M

    2015-11-01

    Irreversibility is one of the most intriguing concepts in physics. While microscopic physical laws are perfectly reversible, macroscopic average behavior has a preferred direction of time. According to the second law of thermodynamics, this arrow of time is associated with a positive mean entropy production. Using a nuclear magnetic resonance setup, we measure the nonequilibrium entropy produced in an isolated spin-1/2 system following fast quenches of an external magnetic field. We experimentally demonstrate that it is equal to the entropic distance, expressed by the Kullback-Leibler divergence, between a microscopic process and its time reversal. Our result addresses the concept of irreversibility from a microscopic quantum standpoint. PMID:26588367

  9. A Parametric Study Delineating Irreversible Electroporation from Thermal Damage Based on a Minimally Invasive Intracranial Procedure

    OpenAIRE

    Ellis Thomas L; Neal Robert E; Rossmeisl John H; Garcia Paulo A; Davalos Rafael V

    2011-01-01

    Abstract Background Irreversible electroporation (IRE) is a new minimally invasive technique to kill undesirable tissue in a non-thermal manner. In order to maximize the benefits from an IRE procedure, the pulse parameters and electrode configuration must be optimized to achieve complete coverage of the targeted tissue while preventing thermal damage due to excessive Joule heating. M...

  10. Superpositions in Prigogine's approach to irreversibility for physical and financial applications

    OpenAIRE

    Carfi', David

    2008-01-01

    In this paper we apply the theory of superpositions for Radon measures on compact subsets of the real Euclidean n-space Rn to Prigogine's approach in the study of irreversible processes, which emerge in physics and in economics, showing that the superposition is a natural rigorous tool feasible to face the problem.

  11. Relativistic thermodynamics of irreversible processes I. Heat conduction, diffusion, viscous flow and chemical reactions; formal part

    NARCIS (Netherlands)

    Kluitenberg, G.A.; Groot, S.R. de; Mazur, P.

    1953-01-01

    The relativistic thermodynamics of irreversible processes is developed for an isotropic mixture in which heat conduction, diffusion, viscous flow, chemical reactions and their cross-phenomena may occur. The four-vectors, representing the relative flows of matter, are defined in such a way that, in t

  12. Pulpitis irreversible como forma de presentación de un odontoma

    OpenAIRE

    Berástegui, Esther; Buenechea Imaz, Ramón

    1997-01-01

    Se presenta un caso de odontoma compuesto que provocó pulpitis irreversible en el incisivo central superior derecho (1,1) en una joven de 20 años. El tratamiento fue la biopulpectomía total y extirpación quirúrgica del tumor.

  13. Site-specific properties and irreversible vegetation changes in semi-arid grazing systems

    NARCIS (Netherlands)

    Rietkerk, M; vandenBosch, F; vandeKoppel, J

    1997-01-01

    There is an urgent need to develop a mechanistic understanding of how site-specific properties can lead to irreversible vegetation changes. We show, by means of a bifurcation analysis of two mathematical models, how site-specific properties determine the resilience of vegetation changes in semi-arid

  14. How to account for irreversibility in integrated assessment of climate change?

    International Nuclear Information System (INIS)

    How to account for irreversibility in integrated assessment of climate change? This Ph. D. thesis in Economics balances discounting, technical progress and the inertia of existing capital stock against uncertainty and the inertia of socio-economic systems to examine the issue of near term limitations of greenhouse gases emissions. After a general overview in chapter 2, and a more historical presentation of the debates in chapter 3, chapter 4 proceeds to review a large number of integrated assessment models. Chapter 5 introduces a Model on the Dynamics of Inertia and Adaptability of energy systems: DIAM, used to discuss how much previous studies might have overestimated the long term costs of CO2 limitations and underestimated adjustment costs. It shows that, given a target date for atmospheric CO2 concentration stabilisation, a higher inertia implies a lower optimal concentration trajectory. In a sequential decision framework, chapter 6 shows that current uncertainties about which CO2 concentration ceiling would not present dangerous interference with the climate system justifies precautionary action. Finally, chapter 7 uses the irreversibility effect theory to define formally situations of decision under controversy and compare the irreversibility of CO2 accumulation with the irreversibility of investments needed to moderate it. An option value for greenhouse gases emissions limitations is computed. (author)

  15. Irreversible thermodynamics of dark energy on the entropy-corrected apparent horizon

    Energy Technology Data Exchange (ETDEWEB)

    Karami, K; Sahraei, N [Department of Physics, University of Kurdistan, Pasdaran Street, Sanandaj (Iran, Islamic Republic of); Jamil, M, E-mail: KKarami@uok.ac.i, E-mail: mjamil@camp.nust.edu.p [Center for Advanced Mathematics and Physics (CAMP), National University of Sciences and Technology (NUST), Islamabad (Pakistan)

    2010-10-15

    We study the irreversible (non-equilibrium) thermodynamics of the Friedmann-Robertson-Walker (FRW) universe containing only dark energy. Using the modified entropy-area relation that is motivated by loop quantum gravity, we calculate the entropy-corrected form of the apparent horizon of the FRW universe.

  16. Profit rate performance optimization for a generalized irreversible combined refrigeration cycle

    Indian Academy of Sciences (India)

    Kang Ma; Lingen Chen; Fengrui Sun

    2009-10-01

    Finite-time exergoeconomic performance of a Newtonian heat transfer law system generalized irreversible combined refrigeration cycle model with finite-rate heat transfer, heat leakage and internal irreversibility is presented in this paper. The operation of the generalized irreversible combined refrigeration cycle is viewed as a production process with exergy as its output. The performance optimization of the cycle is performed by taking profit as the objective. The optimal profit rate, optimal COP (coefficient of performance), as well as the relation between the optimal profit rate and COP of the cycle are derived. The focus of this paper is to obtain the compromise optimization between economics (profit rate) and the energy utilization factor (COP) for the cycle, by searching the optimum COP at maximum profit rate, which is termed as the finite time exergoeconomic performance bound. Moreover, the effects of various factors, including heat leakage, internal irreversibility and the price ratio, on the profit rate performance of the cycle are analysed by detailed numerical examples.

  17. Use of atomic force microscopy to quantify slip irreversibility in a nickel-base superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Risbet, M.; Feaugas, X.; Guillemer-Neel, C.; Clavel, M

    2003-09-15

    Atomic force microscopy was used to study the evolution of surface deformation during cyclic loading in a nickel-base superalloy. Cyclic slip irreversibility has been investigated using quantitative evaluation of extrusion heights and inter-band spacing. This approach is applied to formulate a microscopic crack initiation law, compared to a classical Manson-Coffin relationship.

  18. Use of atomic force microscopy to quantify slip irreversibility in a nickel-base superalloy

    International Nuclear Information System (INIS)

    Atomic force microscopy was used to study the evolution of surface deformation during cyclic loading in a nickel-base superalloy. Cyclic slip irreversibility has been investigated using quantitative evaluation of extrusion heights and inter-band spacing. This approach is applied to formulate a microscopic crack initiation law, compared to a classical Manson-Coffin relationship

  19. Kinetic Studies on the Irreversible Inhibition of Restriction Endonuclease Pst I by Site-Specific Inhibitors

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The irreversible modifying effects on Pst I of several inhibitors have been studied with the irreversible inhibition kinetic theory of single substrate reaction provided by Tsou,C. L. Pyridoxal phosphate (PLP), p-chloromercuribenzoic acid (PCMB),diisopropyl fluorophosphate (DFP), 2,3-diacetyl (DAC) and N-ethyl-5-phenylisoxazoliun-3'-sulfonate (woodward's reagent K, WRK ) modify the lysine, cysine,serteine, arginine and carboxyl groups of the protein molecule respectively. These five inhibitors have been found to inhibit both the prime activity and star activity of Pst 1. Used with the irreversible inhibition theory,the apparent inhibition rate constant, A and the microcosmic inhibition rate constants, k+0 and k′ +o of every inhibitor were calculated. We also found that their inhibition effects belong to the noncompetitive irreversible inhibition. Results show that among the groups to be modified, some have nothing to do with the combination with the substrate, and some may have, but any of them isn't the only factor involved in the specific binding.Despite all this, they may take part in the catalysis of enzyme or have important effects on maintaining the active structure of enzyme molecules. Furthermore, serine and arginine residues are related to the alteration of Pst I conformation and then influence the ability of Pst I recognizing and incising DNA specifically.

  20. Irreversibility and multiplicity: two criteria for the disposal of nuclear wastes

    International Nuclear Information System (INIS)

    Two criteria are suggested for comparing waste management methods: technical irreversibility and site multiplicity. These criteria can be used to reduce future risk in the face of inherent uncertainty and to provide for safe disposal without requiring guaranteed future ability to recognize, detect or repair areas of failure

  1. Imaging of irreversible loss of brain function; Bildgebende Verfahren zur Diagnostik des irreversiblen Hirnfunktionsausfalles

    Energy Technology Data Exchange (ETDEWEB)

    Lanfermann, H. [Hannover Medical School (Germany). Inst. of Diagnostic and Interventional Neuroradiology; Schober, O. [University Hospital Muenster (Germany). Dept. of Nuclear Medicine

    2016-01-15

    The updated guidelines for the determination of irreversible loss of brain function include a substantial innovation, i. e., the use of CT angiography as a supplementary technical examination. Adherence to a standardized protocol is the prerequisite for the application of CT angiography. The guidelines for standardized execution of perfusion scintigraphy are unchanged and still valid. Requirements regarding the quality of examining physicians are specified.

  2. Predictive charge-regulation transport model for nanofiltration from the theory of irreversible processes

    NARCIS (Netherlands)

    Lint, de W.B. Samuel; Benes, Nieck E.

    2004-01-01

    The charge-regulation concept is combined with the theory of irreversible processes to predict multi-component electrolyte transport in nanofiltration membranes. Charging of the membrane surface is described using a 1-pK site-binding model with a triple-layer electrostatic description. Mass transpor

  3. Stripping chronopotentiometry at scanned deposition (SSCP). Part 3. Irreversible electrode reactions

    NARCIS (Netherlands)

    Leeuwen, van H.P.; Town, R.M.

    2003-01-01

    A rigorous expression is derived for the scanned deposition potential stripping chronopotentiometry (SSCP) curve for the case of quasi-reversible and irreversible redox reactions. The equation is fully applicable to both a conventional (macro) electrode and a microelectrode. SSCP curves are shown to

  4. Modelling plastic deformation of metals over a wide range of strain rates using irreversible thermodynamics

    NARCIS (Netherlands)

    Huang, M.; Rivera-Diaz-del-Castillo, P.E.J.; Bouaziz, O.; Van der Zwaag, S.

    2009-01-01

    Based on the theory of irreversible thermodynamics, the present work proposes a dislocation-based model to describe the plastic deformation of FCC metals over wide ranges of strain rates. The stress-strain behaviour and the evolution of the average dislocation density are derived. It is found that t

  5. Three Body Multichannel Scattering as a Model of Irreversible Quantum Mechanics

    OpenAIRE

    Bogdanov, Alexander V.; Gevorkyan, Ashot S.

    1997-01-01

    The new formulation of the theory of multichannel scattering on the example of collinear model is proposed. It is shown, that in the closed three-body scattering system the principle of quantum determinism in general case breaks down and we have a micro- irreversible quantum mechanics.

  6. Ojo por ojo

    OpenAIRE

    Ramón del Llano Ibáñez

    2011-01-01

    Nuestro pan y café de la mañana se acompaña de noticias alrededor de ejecuciones, de fosas clandestinas, de batallas del ejército, de balaceras en las calles y civiles caídos por balas perdidas : la muerte acompaña nuestro desayuno. Las calaveras de azúcar del día de muertos hoy son calaveras reales y amargas : 40 000 muertos en cuatro años después que el Presidente Calderón declaró la guerra a los narcotraficantes. Se han apresado a varios e importantes miembros de los cárteles : pero han si...

  7. Sepsis por shigella flexneri

    Directory of Open Access Journals (Sweden)

    César Cabrera C

    2005-04-01

    Full Text Available Se presenta un caso raro de sepsis por Shigella flexneri en una paciente de 45 años de edad quien estando hospitalizada para el estudio de un tumor cerebral, requirió el uso de manitol y dosis altas de corticoides; luego de ello presenta deposiciones líquidas con moco y sangre, desarrolla síndrome de respuesta inflamatoria sistémica, luego se aísla Shigella flexneri en el hemocultivo; recibió tratamiento antibiótico con ciprofloxacina. Se describen las características del caso y se comenta de acuerdo con la revisión de literatura.

  8. Onicomicosis por hongos fuliginosos

    Directory of Open Access Journals (Sweden)

    Ingrid Salas-Campos

    2009-12-01

    Full Text Available Justificación y objetivo: Las infecciones de las uñas producidas por hongos son un problema de frecuente consulta dermatológica. Los dermatofitos son la mayor causa de estas infecciones, siendo Trichophyton rubrum el agente etiológico más importante. Sin embargo, los hongos no dermatofitos, tanto hialinos como fuliginosos, pueden ser también responsables de estos cuadros clínicos. Debido a que estos hongos tienden a ser resistentes a los antimicóticos comúnmente usados para tratar las onicomicosis, es que se hace indispensable que el clínico se asegure por medio de un examen de laboratorio de la etiología de la infección. Métodos: Se estudiaron tres casos de pacientes con lesiones en uñas, que acudieron al laboratorio de Micología Médica, Facultad de Microbiología, Universidad de Costa Rica. Se realizaron los análisis de rutina para aislamiento e identificación de hongos patógenos. Resultados: En los tres casos estudiados se observó al examen directo micelio fuliginoso. En uno de los casos se aisló e identificó Scytalidium dimidiatum, hongo que presenta resistencia a los antifúngicos utilizados para tratar onicomicosis. Conclusión. El reporte de hongos diferentes a los dermatofitos como agentes etiológicos de onicomicosis es importante para que el médico pueda elegir el tratamiento más recomendado para este tipo de infección.

  9. Motivado por cirujanos

    Directory of Open Access Journals (Sweden)

    Carlos Salazar-Vargas

    2010-12-01

    Full Text Available Comenzaba la década de los 60 y nuestro grupo nerviosamente iniciaba lecciones en los hospitales de San José. En aquellos años, el estudiante de medicina empezaba su contacto con pacientes, por lo menos 1 ó 2 años después de iniciada la carrera. El estudio del ser humano normal que ya habíamos concluido, continuaba con el del enfermo, y más adelante aprenderíamos el tratamiento. La enfermedad descrita en el libro, de pronto se convertía en un enfermo, y es a este quien hoy veíamos, cohibido pero inquisidor, en la cama de un hospital. Los profesores nos enseñaban a interrogar y a examinar a los pacientes, y cada gesto suyo, cada pregunta, cada maniobra, eran celosamente guardados en la memoria de los educandos. Con claridad percibíamos, aun a temprana edad, las diferencias entre los especialistas, y casi de manera involuntaria, cada quien iba tomando partido y escogía su futuro camino. Fue durante esos tempranos años, cuando mi vida se cruzó con la de 7 maravillosas personas y excelentes cirujanos, que marcaron para siempre mi destino y, sin quererlo ellos, me hicieron inclinarme por la cirugía. Dos eran serios y profundamente académicos: el Dr. Manuel Aguilar Bonilla y el Dr. Vesalio Guzmán Calleja; 3, decididos, incansables y muy hábiles: el Dr. Longino Soto Pacheco, el Dr. Claudio Orlich Carranza y el Dr. Carlos Prada Díaz, y 2, abordables, prácticos, joviales y amistosos: el Dr. Fernando Valverde Soley y el Dr. Randall Ferris Iglesias….

  10. Quantum thermodynamics: Microscopic foundations of entropy and of entropy generation by irreversibility

    Directory of Open Access Journals (Sweden)

    Beretta, Gian Paolo

    2008-02-01

    Full Text Available What is the physical significance of entropy? What is the physical origin of irreversibility? Do entropy and irreversibility exist only for complex and macroscopic systems? Most physicists still accept and teach that the rationalization of these fundamental questions is given by Statistical Mechanics. Indeed, for everyday laboratory physics, the mathematical formalism of Statistical Mechanics (canonical and grand-canonical, Boltzmann, Bose-Einstein and Fermi-Dirac distributions allows a successful description of the thermodynamic equilibrium properties of matter, including entropy values. However, as already recognized by Schrodinger in 1936, Statistical Mechanics is impaired by conceptual ambiguities and logical inconsistencies, both in its explanation of the meaning of entropy and in its implications on the concept of state of a system. An alternative theory has been developed by Gyftopoulos, Hatsopoulos and the present author to eliminate these stumbling conceptual blocks while maintaining the mathematical formalism so successful in applications. To resolve both the problem of the meaning of entropy and that of the origin of irreversibility we have built entropy and irreversibility into the laws of microscopic physics. The result is a theory, that we call Quantum Thermodynamics, that has all the necessary features to combine Mechanics and Thermodynamics uniting all the successful results of both theories, eliminating the logical inconsistencies of Statistical Mechanics and the paradoxes on irreversibility, and providing an entirely new perspective on the microscopic origin of irreversibility, nonlinearity (therefore including chaotic behavior and maximal-entropy-generation nonequilibrium dynamics. In this paper we discuss the background and formalism of Quantum Thermodynamics including its nonlinear equation of motion and the main general results. Our objective is to show in a not-too-technical manner that this theory provides indeed a

  11. Using irreversible compression in digital radiology: a preliminary study of the opinions of radiologists

    Science.gov (United States)

    Seeram, Euclid

    2006-03-01

    The large volumes of digital images produced by digital imaging modalities in Radiology have provided the motivation for the development of picture archiving and communication systems (PACS) in an effort to provide an organized mechanism for digital image management. The development of more sophisticated methods of digital image acquisition (Multislice CT and Digital Mammography, for example), as well as the implementation and performance of PACS and Teleradiology systems in a health care environment, have created challenges in the area of image compression with respect to storing and transmitting digital images. Image compression can be reversible (lossless) or irreversible (lossy). While in the former, there is no loss of information, the latter presents concerns since there is a loss of information. This loss of information from diagnostic medical images is of primary concern not only to radiologists, but also to patients and their physicians. In 1997, Goldberg pointed out that "there is growing evidence that lossy compression can be applied without significantly affecting the diagnostic content of images... there is growing consensus in the radiologic community that some forms of lossy compression are acceptable". The purpose of this study was to explore the opinions of expert radiologists, and related professional organizations on the use of irreversible compression in routine practice The opinions of notable radiologists in the US and Canada are varied indicating no consensus of opinion on the use of irreversible compression in primary diagnosis, however, they are generally positive on the notion of the image storage and transmission advantages. Almost all radiologists are concerned with the litigation potential of an incorrect diagnosis based on irreversible compressed images. The survey of several radiology professional and related organizations reveals that no professional practice standards exist for the use of irreversible compression. Currently, the

  12. Multi-objective optimization of an irreversible Stirling cryogenic refrigerator cycle

    International Nuclear Information System (INIS)

    Highlights: • A parametric investigation of irreversible Stirling cryogenic refrigerator cycles is presented. • Both internal and external irreversibilities are included in this study, moreover, heat capacities of external reservoirs are involved. • Multi-objective evolutionary algorithm based on NSGA-II approach is utilized. • Three robust decision making approaches are utilized to determine final optimum solution. - Abstract: The main aim of this research article is a parametric demonstration of irreversible Stirling cryogenic refrigerator cycles that includes irreversibilities such as external and internal irreversibilities. In addition, through this study, finite heat capacities of external reservoirs are considered accordingly. To reach the addressed goal of this research, three objective functions that include the input power of the Stirling refrigerator, the coefficient of performance (COP) and cooling load (RL) have been involved in optimization process simultaneously. The first aforementioned objective function has to minimize; the rest objective functions, on the other hand, have to maximize in parallel optimization process. Developed multi objective evolutionary approaches (MOEAs) based on NSGA-II algorithm is implemented throughout this work. Moreover, cold-side’s effectiveness of the heat exchanger, hot-side’s effectiveness of the heat exchanger, heat source’s heat capacitance rate, heat sink’s capacitance rate, temperature ratio ((Th)/(Tc) ), temperature of cold side are assigned as decision variables for decision making procedure. To gain a robust decision, different decision making approaches that include TOPSIS, LINMAP and fuzzy Bellman–Zadeh are used. Pareto optimal frontier was determined precisely and then three final outputs have been gained by means of the mentioned decision making approaches

  13. [Determination of irreversibility of clinical brain death. Electroencephalography and evoked potentials].

    Science.gov (United States)

    Buchner, H; Ferbert, A

    2016-02-01

    Principally, in the fourth update of the rules for the procedure to finally determine the irreversible cessation of function of the cerebrum, the cerebellum and the brainstem, the importance of an electroencephalogram (EEG), somatosensory evoked potentials (SEP) and brainstem auditory evoked potentials (BAEP) are confirmed. This paper presents the reliability and validity of the electrophysiological diagnosis, discusses the amendments in the fourth version of the guidelines and introduces the practical application, problems and sources of error.An EEG is the best established supplementary diagnostic method for determining the irreversibility of clinical brain death syndrome. It should be noted that residual brain activity can often persist for many hours after the onset of brain death syndrome, particularly in patients with primary brainstem lesions. The derivation and analysis of an EEG requires a high level of expertise to be able to safely distinguish artefacts from primary brain activity. The registration of EEGs to demonstrate the irreversibility of clinical brain death syndrome is extremely time consuming.The BAEPs can only be used to confirm the irreversibility of brain death syndrome in serial examinations or in the rare cases of a sustained wave I or sustained waves I and II. Very often, an investigation cannot be reliably performed because of existing sound conduction disturbances or failure of all potentials even before the onset of clinical brain death syndrome. This explains why BAEPs are only used in exceptional cases.The SEPs of the median nerve can be very reliably derived, are technically simple and with few sources of error. A serial investigation is not required and the time needed for examination is short. For these reasons SEPs are given preference over EEGs and BAEPs for establishing the irreversibility of clinical brain death syndrome. PMID:26785843

  14. Lie-Admissible Invariant Origin of Irreversibility for Matter and Antimatter at the Classical and Operator Levels

    CERN Document Server

    Santilli, R M

    2006-01-01

    It was generally believed throughout the 20-th century that irreversibility is a purely classical event without operator counterpart. However, a classical irreversible system cannot be consistently decomposed into a finite number of reversible quantum particles (and, vice versa), thus establishing that the origin of irreversibility is basically unknown at the dawn of the 21-th century. To resolve this problem, we adopt the historical an- alytic representation of irreversibility by Lagrange and Hamilton with external terms in their analytic equations; we show that, when properly written, the brackets of the time evolution characterize covering Lie-admissible algebras; we show that the for- malism has a fully consistent operator counterpart given by the Lie-admissible branch of hadronic mechanics; we identify catastrophic mathematical and physical inconsis- tencies when irreversible formulations are treated with the conventional mathematics used for reversible systems; and show that, when the dynamical equation...

  15. Sociedad por Acciones Simplificada

    Directory of Open Access Journals (Sweden)

    Carlos Andrés Arcila Salazar

    2009-06-01

    Full Text Available En Colombia, aspectos como la responsabilidad limitada; supresión de la llamada doctrina de ultra vires; duración ilimitada; eliminación de la regla, una acción, un voto; remedios al abuso de los derechos; posibilidad de eliminar prohibiciones a los administradores, libertad de establecer restricciones para la transferencia de acciones y la simplificación de los procedimientos de fusión; son inviables bajo nuestra legislación. Sin embargo, la Ley 1258 de 2008, ha incorporado al derecho societario colombiano un nuevo tipo societario híbrido, llamado “Sociedad por Acciones Simplificada”. Esta forma societaria híbrida se basa en un principio básico: garantizar amplia libertad a los empresarios en la estructuración de sus relaciones a través de disposiciones contractuales. La S.A.S. provee a los empresarios significativa flexibilidad contractual, a la vez que preserva beneficios como la limitación de la responsabilidad.

  16. Sociedad por Acciones Simplificada

    Directory of Open Access Journals (Sweden)

    Carlos Andrés Arcila Salazar

    2009-07-01

    Full Text Available En Colombia, aspectos como la responsabilidad limitada; supresión de la llamada doctrina de ultra vires; duración ilimitada; eliminación de la regla, una acción, un voto; remedios al abuso de los derechos; posibilidad de eliminar prohibiciones a los administradores, libertad de establecer restricciones para la transferencia de acciones y la simplificación de los procedimientos de fusión; son inviables bajo nuestra legislación. Sin embargo, la Ley 1258 de 2008, ha incorporado al derecho societario colombiano un nuevo tipo societario híbrido, llamado “Sociedad por Acciones Simplificada”. Esta forma societaria híbrida se basa en un principio básico: garantizar amplia libertad a los empresarios en la estructuración de sus relaciones a través de disposiciones contractuales. La S.A.S. provee a los empresarios significativa flexibilidad contractual, a la vez que preserva beneficios como la limitación de la responsabilidad.

  17. Irreversible electrical manipulation of magnetization on BiFeO{sub 3}-based heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Qingyu, E-mail: xuqingyu@seu.edu.cn, E-mail: jdu@nju.edu.cn; Xu, Zhenyu [Department of Physics, Southeast University, Nanjing 211189 (China); Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 210096 (China); Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123 (China); He, Maocheng; Du, Jun, E-mail: xuqingyu@seu.edu.cn, E-mail: jdu@nju.edu.cn [Department of Physics and National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); Cao, Yanqiang [Department of Materials Science and Engineering, Nanjing University, Nanjing 210008 (China)

    2015-05-07

    We prepared several heterostructures, Co/Bi{sub 0.90}La{sub 0.10}FeO{sub 3} on surface oxidized Si or (111) SrTiO{sub 3} and NiFe/Bi{sub 0.90}La{sub 0.10}FeO{sub 3} on (001) SrTiO{sub 3} substrates using LaNiO{sub 3} as bottom electrode. With different strategies of voltage application, the exchange bias field H{sub E} decreased with increasing voltage irreversibly for all the heterostructures at room temperature. The chemical state at the NiFe/Bi{sub 0.90}La{sub 0.10}FeO{sub 3} interface was studied by X-ray photoelectron spectroscopy before and after the electrical manipulation. The oxidization of the metallic ferromagnetic layer at interface after the electrical manipulation has been confirmed, which might explain the irreversibility.

  18. Irreversible Evolution of a Wave Packet in The Rigged Hilbert Space Quantum Mechanics

    CERN Document Server

    Marcucci, Giulia

    2016-01-01

    It is well known that a state with complex energy cannot be the eigenstate of a self-adjoint operator, like the Hamiltonian. Resonances, i.e. states with exponentially decaying observables, are not vectors belonging to the conventional Hilbert space. One can describe these resonances in an unusual mathematical formalism, based on the so-called Rigged Hilbert Space (RHS). In the RHS, the states with complex energy are denoted as Gamow Vectors (GV), and they model decay processes. We study GV of the Reversed Harmonic Oscillator (RHO), and we analytically and numerically investigate the unstable evolution of wave packets. We introduce the background function to study initial data not composed only by a summation of GV and we analyse different wave packets belonging to specific function spaces. Our work furnishes support to the idea that irreversible wave propagations can be investigated by means of Rigged Hilbert Space Quantum Mechanics and provides insights for the experimental investigation of irreversible dyn...

  19. Immersion disinfection of irreversible hydrocolloid impressions with sodium hypochlorite. Part I: Microbiology.

    Science.gov (United States)

    Beyerle, M P; Hensley, D M; Bradley, D V; Schwartz, R S; Hilton, T J

    1994-01-01

    Current American Dental Association infection control guidelines recommend immersion disinfection of irreversible hydrocolloid impressions, and this study further defines the parameters for use of sodium hypochlorite. Sodium hypochlorite has been shown to be an effective disinfectant for impressions; however, it has not been fully evaluated for optimum immersion time and concentration. In this study, irreversible hydrocolloid impressions contaminated with different bacteria were immersed in varying concentrations of sodium hypochlorite for 1, 5, or 10 minutes. Dilute solutions of sodium hypochlorite (0.525% or 0.0525%) produced a 4-log10 (99.99%) reduction in colony-forming units of Staphylococcus aureus, Salmonella choleraesuis, or Pseudomonas aeruginosa after 1 to 5 minutes' immersion. Full-strength sodium hypochlorite (5.25%) required 5 minutes to produce a 4-log10 reduction of Bacillus subtilis. A 4-log10 reduction of Mycobacterium bovis was not obtained under any conditions examined.

  20. Effects of Detunings on Dynamically Induced Irreversibility in Coherently Driven Systems

    Institute of Scientific and Technical Information of China (English)

    HU Xiang-Ming; PENG Jin-Sheng

    2000-01-01

    Effects of detunings on dynamically induced irreversibilityis studied for coherently driven V systems in which there is no conventional source of irreversible population pumping. For atomic barium (γ1/γ2 = 400 》 1, where γ1 and γ2 are the rates of the spontaneous decay from the excited states 6s6p 1P1 and 6s6p 3p1 to the ground state 6s2 1So, espectively), the strong irreversibility is found to lead to a maximum inversion of 0.77 [only 0.1 in Phys. Rev. Lett. 71 (1993) 4311]. The maximum population inversion requires relatively strong fields coupled respectively to two transitions, a disparity in two atomic decay rates, and the atom-field detunings of opposite signs. However, it is also shown that even in the cases where two detunings have the same sign, or where two decay rates are equal, population inversion takes place.

  1. Suppression of irreversible capacity loss in Li-rich layered oxide by fluorine doping

    Science.gov (United States)

    Song, Jay Hyok; Kapylou, Andrei; Choi, Hee Sung; Yu, Byong Yong; Matulevich, Evegeniya; Kang, Sun Ho

    2016-05-01

    Li[Li1/6Ni1/6Co1/6Mn1/2]O2-xFx (x = 0.00 to 0.07) materials were synthesized with low temperature heat treatment (700 °C) and their electrochemical performances were evaluated. With the addition of fluorine, the reversible capacity significantly increased as the irreversibility was suppressed during the first cycle. The reduction of irreversibility was mainly attributed to the enhanced first cycle efficiency of Li2MnO3-like component after the fluorine addition. By combining results of the X-ray diffraction (XRD), secondary ion mass spectrometry (SIMS), In-situ X-ray absorption spectroscopy (XAS) analyses, and first principle calculations, it was proposed that the presence of fluorine facilitated the reduction of cobalt and manganese ions in Li-rich layered oxide, and that the reduced transition metal (TM) ions suppressed structural changes.

  2. Coefficient of performance under optimized figure of merit in minimally nonlinear irreversible refrigerator

    Science.gov (United States)

    Izumida, Y.; Okuda, K.; Calvo Hernández, A.; Roco, J. M. M.

    2013-01-01

    We apply the model of minimally nonlinear irreversible heat engines developed by Izumida and Okuda (EPL, 97 (2012) 10004) to refrigerators. The model assumes extended Onsager relations including a new nonlinear term accounting for dissipation effects. The bounds for the optimized regime under an appropriate figure of merit and the tight-coupling condition are analyzed and successfully compared with those obtained previously for low-dissipation Carnot refrigerators in the finite-time thermodynamics framework. Besides, we study the bounds for the nontight-coupling case numerically. We also introduce a leaky low-dissipation Carnot refrigerator and show that it serves as an example of the minimally nonlinear irreversible refrigerator, by calculating its Onsager coefficients explicitly.

  3. Thermo-economic and thermodynamic analysis and optimization of a two-stage irreversible heat pump

    International Nuclear Information System (INIS)

    Highlights: • Thermodynamic modeling of a two-stage irreversible heat pump is performed. • The latter is achieved using NSGA algorithm and thermodynamic analysis. • 3 answers given by the decision-making methods selected. - Abstract: This research study mainly deals with a comprehensive thermodynamic modeling and thermo-economic optimization of an irreversible absorption heat pump. For the optimization goal, various objective functions are considered comprising the specific heating load, coefficient of performance (COP) and the thermo-economic benchmark (F). In order to specify the optimum design variables, non-dominant sorting genetic algorithm (NSGA) is applied satisfying some restrictions. In this optimization study, all three objective functions (e.g. COP, F and specific heating load) are maximized. In addition, decision making is carried out using three well-suited approaches namely LINAMP and TOPSIS and FUZZY. Finally, sensitivity analysis and error analysis are conducted in order to improve understanding of the system performance

  4. Immersion disinfection of irreversible hydrocolloid impressions with sodium hypochlorite. Part II: Effect on gypsum.

    Science.gov (United States)

    Vandewalle, K S; Charlton, D G; Schwartz, R S; Reagan, S E; Koeppen, R G

    1994-01-01

    This study investigated the effects of various immersion times and concentrations of sodium hypochlorite on irreversible hydrocolloid impressions and resultant gypsum casts. Irreversible hydrocolloid impressions of a test die were immersed for 1, 5, or 10 minutes in water (control), 5.25%, 0.525%, and 0.0525% sodium hypochlorite and then cast in a Type III stone and a Type V stone. Each stone specimen was evaluated for detail reproduction, dimensional change, surface roughness, and surface hardness. The results indicated that impressions may be immersed in sodium hypochlorite for any of the experimental times and concentrations without negative effects on Type V stone casts. However, immersion of impressions in 5.25% sodium hypochlorite causes some surface deterioration on Type III stone casts. PMID:7993542

  5. Lagrangian formulation of irreversible thermodynamics and the second law of thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Glavatskiy, K. S. [School of Applied Sciences, RMIT University, GPO Box 2476, Melbourne, Victoria 3001 (Australia)

    2015-05-28

    We show that the equations which describe irreversible evolution of a system can be derived from a variational principle. We suggest a Lagrangian, which depends on the properties of the normal and the so-called “mirror-image” system. The Lagrangian is symmetric in time and therefore compatible with microscopic reversibility. The evolution equations in the normal and mirror-imaged systems are decoupled and describe therefore independent irreversible evolution of each of the systems. The second law of thermodynamics follows from a symmetry of the Lagrangian. Entropy increase in the normal system is balanced by the entropy decrease in the mirror-image system, such that there exists an “integral of evolution” which is a constant. The derivation relies on the property of local equilibrium, which states that the local relations between the thermodynamic quantities in non-equilibrium are the same as in equilibrium.

  6. Immersion disinfection of irreversible hydrocolloid impressions with sodium hypochlorite. Part I: Microbiology.

    Science.gov (United States)

    Beyerle, M P; Hensley, D M; Bradley, D V; Schwartz, R S; Hilton, T J

    1994-01-01

    Current American Dental Association infection control guidelines recommend immersion disinfection of irreversible hydrocolloid impressions, and this study further defines the parameters for use of sodium hypochlorite. Sodium hypochlorite has been shown to be an effective disinfectant for impressions; however, it has not been fully evaluated for optimum immersion time and concentration. In this study, irreversible hydrocolloid impressions contaminated with different bacteria were immersed in varying concentrations of sodium hypochlorite for 1, 5, or 10 minutes. Dilute solutions of sodium hypochlorite (0.525% or 0.0525%) produced a 4-log10 (99.99%) reduction in colony-forming units of Staphylococcus aureus, Salmonella choleraesuis, or Pseudomonas aeruginosa after 1 to 5 minutes' immersion. Full-strength sodium hypochlorite (5.25%) required 5 minutes to produce a 4-log10 reduction of Bacillus subtilis. A 4-log10 reduction of Mycobacterium bovis was not obtained under any conditions examined. PMID:7916888

  7. Irreversible Change of the Pore Structure of ZIF-8 in Carbon Dioxide Capture with Water Coexistence

    DEFF Research Database (Denmark)

    Liu, Huang; Guo, Ping; Regueira Muñiz, Teresa;

    2016-01-01

    showed an irreversible change of its framework, which occurs during the CO2 capture process. It was found that there is an irreversible chemical reaction among ZIF-8, water, and CO2, which creates both zinc carbonate (or zinc carbonate hydroxides) and single 2-methylimidazole crystals, and therefore......The performance of zeolitic imidazolate framework 8 (ZIF-8) for CO2 capture under three different conditions (wetted ZIF-8, ZIF-8/water slurry, and ZIF-8/water-glycol slurry) was systemically investigated. This investigation included the study of the pore structure stability of ZIF-8 by using X...... the pore structure of ZIF-8 collapses. It is suggested therefore that care must be taken when using ZIF-8 or products containing ZIF-8 for gas capture, gas separation, or other applications where both water and acid gases coexist....

  8. Labile phytochrome and photoperiodic flower induction in Pharbitis nil Chois. The irreversible phytochrome hypothesis

    Directory of Open Access Journals (Sweden)

    Mariusz Cymerski

    2014-02-01

    Full Text Available Seedlings of Pharbitis nil cultivated under non-inductive conditions of white light were subjected to generative induction applying one 16-hour-long period of inductive night. During the eighth hour the night was interrupted with 1 min of red light pulse which completely inhibited the flowering. Treating the plants with KCN blocked the inhibiting effect of red light. Because KCN lowers considerably the rate of destruction of labile Pfd in some plant systems, it seems probable that red light night-break irradiation (without KCN, which blocked the flowering, leads also to the accumulation of unknown Pfd destruction products (irreversible phytochrome. It also suggests that it is not the labile PfrI itself but the products of its irreversible transformation that could be active in the photoperiodic control of flowering.

  9. Aspergillosis in immunocompromised children acute myeloid leukemia and bone marrow aplasia.: Report of two cases Aspergilose em crianças imunocomprometidas com leucemia mielóide aguda e aplasta de medula óssea: Registro de 2 casos

    Directory of Open Access Journals (Sweden)

    Maria Zilda de Aquino

    1994-10-01

    Full Text Available Two cases of Aspergillosis in immunocompromised children are reported. Both were caused by Aspergillns flavus. Early diagnosis and treatment led to the remission of the process. One patient had acute myeloid leukemia; the fungus was isolated from the blood. The other patient with bone marrow aplasia, presented an invasive aspergillosis of the paranasal sinuses with dissemination of fungal infection; the diagnosis was obtained by histology and culture of biopsied tissue from a palatal ulceration.No presente trabalho são registrados dois casos de aspergilose em crianças imunocomprometidas. O estudo micológico completo identificou Aspergillus flavus como agente dos dois processos. A presença cada vez mais frequente da aspergilose invasiva deve-se ao número crescente de pacientes imunocomprometidos, muitos com hemopatias graves submetidos à quimioterapia. O diagnóstico precoce em um dos casos possibilitou remissão do processo. Tratava-se de paciente com leucemia mielóide aguda, tendo sido isolado o fungo do sangue circulante. O segundo caso evoluiu para óbito, com infecção fúngica generalizada.

  10. Long-term outcome of individuals with pure red cell aplasia and antierythropoietin antibodies in patients treated with recombinant epoetin: a follow-up report from the Research on Adverse Drug Events and Reports (RADAR) Project

    Science.gov (United States)

    Bennett, Charles L.; Cournoyer, Denis; Carson, Kenneth R.; Rossert, Jerome; Luminari, Stefano; Evens, Andrew M.; Locatelli, Francesco; Belknap, Steven M.; McKoy, June M.; Lyons, E. Alison; Kim, Benjamin; Sharma, Rishi; Costello, Stacey; Toffelmire, Edwin B.; Wells, George A.; Messner, Hans A.; Yarnold, Paul R.; Trifilio, Steven M.; Raisch, Dennis W.; Kuzel, Timothy M.; Nissenson, Allen; Lim, Lay-Cheng; Tallman, Martin S.; Casadevall, Nicole

    2005-01-01

    Since its introduction in 1988, recombinant human erythropoietin (epoetin) has been standard treatment for patients with anemia due to chronic kidney disease. From 1998 to 2004, nearly 200 epoetin-treated persons with chronic kidney disease developed antibodies to epoetin, resulting in pure red cell aplasia (PRCA). The majority of these patients received Eprex, an epoetin alfa product marketed exclusively outside the United States. Herein, we report on the long-term outcome of these individuals. For 170 chronic kidney disease patients who developed epoetin-associated PRCA and had 3 months or more follow-up information available, case reports from the Food and Drug Administration and epoetin manufacturers were reviewed for information on clinical characteristics of the patients, immunosuppressive treatments, epoetin responsiveness, and hematologic recovery. Overall, 64% of the PRCA patients received immunosuppressive therapy, including 19 who also underwent a renal transplantation. Thirty-seven percent experienced a hematologic recovery, with higher hematologic recovery rates among PRCA patients who received immunosuppressive therapy (57% vs 2%, P < .001). Among 34 patients who received epoetin after the onset of PRCA, 56% regained epoetin responsiveness. The highest rates of epoetin responsiveness were observed among persons whose antierythropoietin antibodies were undetectable when epoetin was administered (89%). Among chronic kidney disease patients with epoetin-associated PRCA, epoetin discontinuation and immunosuppressive therapy or renal transplantation is necessary for hematologic recovery. Reinitiation of epoetin therapy among individuals could be considered if antierythropoietin antibodies are undetectable. PMID:16099877

  11. Irreversible electroporation in the treatment of locally advanced pancreas and liver metastases of colorectal carcinoma

    OpenAIRE

    Wichtowski, Mateusz; Nowaczyk, Piotr; Kocur, Jacek; Murawa, Dawid

    2016-01-01

    Aim of the study Irreversible electroporation is a new, non-thermal ablation technique in the treatment of parenchymal organ tumors which uses short high voltage pulses of electricity in order to induce apoptosis of targeted cells. In this paper the application of this method of treatment in locally advanced pancreatic cancer (LAPC) and liver cancer is analyzed. Material and methods Between 04.2014 and 09.2014 two patients with LAPC and one with colorectal liver metastasis (CRLM) were qualifi...

  12. A statistical model describing combined irreversible electroporation and electroporation-induced blood-brain barrier disruption

    Directory of Open Access Journals (Sweden)

    Sharabi Shirley

    2016-03-01

    Full Text Available Electroporation-based therapies such as electrochemotherapy (ECT and irreversible electroporation (IRE are emerging as promising tools for treatment of tumors. When applied to the brain, electroporation can also induce transient blood-brain-barrier (BBB disruption in volumes extending beyond IRE, thus enabling efficient drug penetration. The main objective of this study was to develop a statistical model predicting cell death and BBB disruption induced by electroporation. This model can be used for individual treatment planning.

  13. A statistical model describing combined irreversible electroporation and electroporation-induced blood-brain barrier disruption

    OpenAIRE

    Sharabi Shirley; Kos Bor; Last David; Guez David; Daniels Dianne; Harnof Sagi; Mardor Yael; Miklavcic Damijan

    2016-01-01

    Background Electroporation-based therapies such as electrochemotherapy (ECT) and irreversible electroporation (IRE) are emerging as promising tools for treatment of tumors. When applied to the brain, electroporation can also induce transient blood-brain-barrier (BBB) disruption in volumes extending beyond IRE, thus enabling efficient drug penetration. The main objective of this study was to develop a statistical model predicting cell death and BBB disruption induced by electroporation. This m...

  14. Local Ablative Strategies for Ductal Pancreatic Cancer (Radiofrequency Ablation, Irreversible Electroporation): A Review

    OpenAIRE

    Salvatore Paiella; Roberto Salvia; Marco Ramera; Roberto Girelli; Isabella Frigerio; Alessandro Giardino; Valentina Allegrini; Claudio Bassi

    2016-01-01

    Pancreatic ductal adenocarcinoma (PDAC) has still a dismal prognosis. Locally advanced pancreatic cancer (LAPC) accounts for the 40% of the new diagnoses. Current treatment options are based on chemo- and radiotherapy regimens. Local ablative techniques seem to be the future therapeutic option for stage-III patients with PDAC. Radiofrequency Ablation (RFA) and Irreversible Electroporation (IRE) are actually the most emerging local ablative techniques used on LAPC. Initial clinical studies on ...

  15. Boltzmann-Equation Based Derivation of Balance Laws in Irreversible Thermodynamics

    OpenAIRE

    Hong, Liu; Yang, Zaibao; Zhu, Yi; Yong, Wen-An

    2014-01-01

    In this paper we propose a novel approach to construct macroscopic balance equations and constitutive equations describing various irreversible phenomena. It is based on the general principles of non-equilibrium thermodynamics and consists of four basic steps: picking suitable state variables, choosing a strictly concave entropy function, separating entropy fluxes and production rates properly, and determining a dissipation matrix. Our approach takes the advantage of both EIT and GENERIC form...

  16. Hydrophilic fraction of natural organic matter causing irreversible fouling of microfiltration and ultrafiltration membranes.

    Science.gov (United States)

    Yamamura, Hiroshi; Okimoto, Kenji; Kimura, Katsuki; Watanabe, Yoshimasa

    2014-05-01

    Although membrane filtration is a promising technology in the field of drinking water treatment, persistent membrane fouling remains a major disadvantage. For more efficient operation, causative agents of membrane fouling need to be identified. Membrane fouling can be classified into physically reversible and irreversible fouling on basis of the removability of the foulants by physical cleaning. Four types of natural organic matter (NOM) in river water used as a source of drinking water were fractionated into hydrophobic and hydrophilic fractions, and their potential to develop irreversible membrane fouling was evaluated by a bench-scale filtration experiment together with spectroscopic and chromatographic analyses. In this study, only dissolved NOM was investigated without consideration of interactions of NOM fractions with particulate matter. Results demonstrated that despite identical total organic carbon (TOC), fouling development trends were significantly different between hydrophilic and hydrophobic fractions. The hydrophobic fractions did not increase membrane resistance, while the hydrophilic fractions caused severe loss of membrane permeability. These results were identical with the case when the calcium was added to hydrophobic and hydrophilic fractions. The largest difference in NOM characteristics between hydrophobic and hydrophilic fractions was the presence or absence of macromolecules; the primary constituent causing irreversible fouling was inferred to be "biopolymers", including carbohydrates and proteins. In addition, the results demonstrated that the extent of irreversible fouling was considerably different depending on the combination of membrane materials and NOM characteristics. Despite identical nominal pore size (0.1 μm), a polyvinylidene fluoride (PVDF) membrane was found to be more rapidly fouled than a PE membrane. This is probably explained by the generation of strong hydrogen bonding between hydroxyl groups of biopolymers and fluorine

  17. REC and NdFe magnetic moment irreversibility from temperature cycling

    Energy Technology Data Exchange (ETDEWEB)

    Hoyer, E.; Chin, J.W.G.; Shuman, D.

    1985-10-01

    Presented are the results of thermal cycling tests carried out on REC and NdFe samples, to determine the irreversible losses in room temperature open circuit magnetic moment. A stabilization prescription was developed for a REC alloy that will allow two 4 day/175/sup 0/C temperature cycles, which simulate two UHV bakeouts, with only a 0.35% average loss and a 0.65% loss variation in the room temperature open circuit magnetic moment after stabilization.

  18. The Market for Used Capital: Endogenous Irreversibility and Reallocation over the Business Cycle

    OpenAIRE

    Andrea Lanteri

    2013-01-01

    This paper explains the procyclicality of capital reallocation documented by Eisfeldt and Rampini (2006) and Cui (2012) by endogenising the resale price of capital in a dynamic general equilibrium model with heterogeneous firms hit by aggregate and idiosyncratic productivity shocks. I build a simple theory of endogenous investment irreversibility by assuming that used investment goods are imperfect substitutes for newly produced ones because of firm-level capital specificity. This creates a d...

  19. Irreversible photo- and radiation-induced effects in amorphous films of arsenic trisulfide

    International Nuclear Information System (INIS)

    It is found that irreversible photo- and radiation-induced effects in virgin As2S3 thin films are accompined by the similar changes of their optical properties. The process of homopolar chemical bond breaking in the thin layer alongside with the creation of the differently charged diamagnetic defects associated with the non-equilibrium breaking of chemical bonds is proper in radiation induced effects, only

  20. Rapid irreversible encephalopathy associated with anti-D immune globulin treatment for idiopathic thrombocytopenic purpura.

    Science.gov (United States)

    Christopher, Kenneth; Horkan, Clare; Barb, Ilie T; Arbelaez, Christian; Hodgdon, Travis A; Yodice, Paul C

    2004-11-01

    Intravenous Rho (D) immune globulin (IV RhIG, WinRho SDF) has been shown to be a safe treatment for idiopathic thrombocytopenic purpura (ITP). Common side effects of IV RhIG include mild hemolysis, febrile reaction, and headache. Significant hemolysis with renal impairment following IV RhIG has been reported. We report a case of irreversible encephalopathy 48 hr following an infusion of IV RhIG for treatment of ITP. PMID:15495245

  1. A Three-Dimensional In Vitro Tumor Platform for Modeling Therapeutic Irreversible Electroporation

    OpenAIRE

    Arena, Christopher B.; Szot, Christopher S.; Garcia, Paulo A.; Rylander, Marissa Nichole; Davalos, Rafael V.

    2012-01-01

    Irreversible electroporation (IRE) is emerging as a powerful tool for tumor ablation that utilizes pulsed electric fields to destabilize the plasma membrane of cancer cells past the point of recovery. The ablated region is dictated primarily by the electric field distribution in the tissue, which forms the basis of current treatment planning algorithms. To generate data for refinement of these algorithms, there is a need to develop a physiologically accurate and reproducible platform on which...

  2. Microbiome of Deep Dentinal Caries Lesions in Teeth with Symptomatic Irreversible Pulpitis

    Science.gov (United States)

    Rôças, Isabela N.; Rachid, Caio T. C. C.; Lima, Kenio C.; Assunção, Isauremi V.; Gomes, Patrícia N.; Siqueira, José F.

    2016-01-01

    This study used a next-generation sequencing approach to identify the bacterial taxa occurring in the advanced front of caries biofilms associated with pulp exposure and irreversible pulpitis. Samples were taken from the deepest layer of dentinal caries lesions associated with pulp exposure in 10 teeth diagnosed with symptomatic irreversible pulpitis. DNA was extracted and the microbiome was characterized on the basis of the V4 hypervariable region of the 16S rRNA gene by using paired-end sequencing on Illumina MiSeq device. Bacterial taxa were mapped to 14 phyla and 101 genera composed by 706 different OTUs. Three phyla accounted for approximately 98% of the sequences: Firmicutes, Actinobacteria and Proteobacteria. These phyla were also the ones with most representatives at the species level. Firmicutes was the most abundant phylum in 9/10 samples. As for genera, Lactobacillus accounted for 42.3% of the sequences, followed by Olsenella (13.7%), Pseudoramibacter (10.7%) and Streptococcus (5.5%). Half of the samples were heavily dominated by Lactobacillus, while in the other half lactobacilli were in very low abundance and the most dominant genera were Pseudoramibacter, Olsenella, Streptococcus, and Stenotrophomonas. High bacterial diversity occurred in deep dentinal caries lesions associated with symptomatic irreversible pulpitis. The microbiome could be classified according to the relative abundance of Lactobacillus. Except for Lactobacillus species, most of the highly prevalent and abundant bacterial taxa identified in this study have been commonly detected in infected root canals. The detected taxa can be regarded as candidate pathogens for irreversible pulpitis and possibly the pioneers in pulp invasion to initiate endodontic infection. PMID:27135405

  3. Uncertainty, instability, and irreversible investment : theory, evidence, and lessons for Africa

    OpenAIRE

    Serven, Luis

    1997-01-01

    A recent (but rapidly growing) literature has focused on how uncertainty and instability affect the adoption of fixed investment projects. That literature shows that if fixed investment projects are costly or impossible to reverse, uncertainty can become a powerful deterrent to investment. The author reviews the literature on irreversible investment to identify the implications for macroeconomic policy and to gauge the practical importance, especially for sub-Saharan Africa, of the link betwe...

  4. IRREVERSIBLE INVESTMENT DECISIONS IN PERENNIAL CROPS WITH YIELD AND PRICE UNCERTAINTY

    OpenAIRE

    Price, T. Jeffrey; Wetzstein, Michael E.

    1999-01-01

    Optimal entry and exit thresholds for Georgia commercial peach production are calculated when both price and yield follow a Brownian motion process. The thresholds are based on an irreversible sunk-cost investment model, where revenue from peach production is affected by the timing of when to enter production. Results indicate stability in Georgia peach production, with growers who are currently producing peaches remaining in production and potential peach growers delaying investment unless t...

  5. A relation between irreversibility and unlinkability for biometric template protection algorithms

    OpenAIRE

    井沼, 学

    2014-01-01

    For biometric recognition systems, privacy protection of enrolled users’ biometric information, which are called biometric templates, is a critical problem. Recently, various template protection algorithms have been proposed and many related previous works have discussed security notions to evaluate the protection performance of these protection algorithms. Irreversibility and unlinkability are important security notions discussed in many related previous works. In this paper, we prove that u...

  6. The Influence of a Metal Stent on the Distribution of Thermal Energy during Irreversible Electroporation

    OpenAIRE

    Scheffer, Hester J.; Vogel, Jantien A; Willemien van den Bos; Neal, Robert E.; van Lienden, Krijn P; Besselink, Marc G. H.; van Gemert, Martin J. C.; van der Geld, Cees W. M.; Meijerink, Martijn R; Klaessens, John H.; Rudolf M. Verdaasdonk

    2016-01-01

    Purpose Irreversible electroporation (IRE) uses short duration, high-voltage electrical pulses to induce cell death via nanoscale defects resulting from altered transmembrane potential. The technique is gaining interest for ablations in unresectable pancreatic and hepatobiliary cancer. Metal stents are often used for palliative biliary drainage in these patients, but are currently seen as an absolute contraindication for IRE due to the perceived risk of direct heating of the metal and its sur...

  7. Irreversible thermodynamic description of interacting dark energy - dark matter cosmological models

    OpenAIRE

    Harko, Tiberiu; Lobo, Francisco S N

    2012-01-01

    We investigate the interaction between dark energy and dark matter in the framework of irreversible thermodynamics of open systems with matter creation/annihilation. We consider dark energy and dark matter as an interacting two component (scalar field and "ordinary" dark matter) cosmological fluid in a homogeneous spatially flat and isotropic Friedmann-Robertson-Walker (FRW) Universe. The thermodynamics of open systems as applied together with the gravitational field equations to the two comp...

  8. Broken versus Non-Broken Time Reversal Symmetry: Irreversibility and Response

    Directory of Open Access Journals (Sweden)

    Sara Dal Cengio

    2016-07-01

    Full Text Available We review some approaches to macroscopic irreversibility from reversible microscopic dynamics, introducing the contribution of time dependent perturbations within the framework of recent developments in non-equilibrium statistical physics. We show that situations commonly assumed to violate the time reversal symmetry (presence of magnetic fields, rotating reference frames, and some time dependent perturbations in reality do not violate this symmetry, and can be treated with standard theories and within standard experimental protocols.

  9. In vivo imaging of irreversible electroporation by means of electrical impedance tomography

    International Nuclear Information System (INIS)

    Electroporation, the increased permeability of cell membranes due to a large transmembrane voltage, is an important clinical tool. Both reversible and irreversible in vivo electroporation are used for clinical applications such as gene therapy and solid malignant tumor ablation, respectively. The primary advantage of in vivo electroporation is the ability to treat tissue in a local and minimally invasive fashion. The drawback is the current lack of control over the process. This paper is the first report of a new method for real-time three-dimensional imaging of an in vivo electroporation process. Using two needle electrodes for irreversible electroporation and a set of electrodes for reconstructing electrical impedance tomography (EIT) images of the treated tissue, we were able to demonstrate electroporation imaging in rodent livers. Histology analysis shows good correlation between the extent of tissue damage caused by irreversible electroporation and the EIT images. This new method may lead the way to real-time control over genetic treatment of diseases in tissue and tissue ablation.

  10. In vivo imaging of irreversible electroporation by means of electrical impedance tomography

    Energy Technology Data Exchange (ETDEWEB)

    Granot, Yair; Maor, Elad; Rubinsky, Boris [Biophysics Graduate Group, University of California at Berkeley, Berkeley, CA 94720 (United States); Ivorra, Antoni [Departments of Mechanical Engineering and Bioengineering, University of California at Berkeley, Berkeley, CA 94720 (United States)], E-mail: yair.granot@gmail.com

    2009-08-21

    Electroporation, the increased permeability of cell membranes due to a large transmembrane voltage, is an important clinical tool. Both reversible and irreversible in vivo electroporation are used for clinical applications such as gene therapy and solid malignant tumor ablation, respectively. The primary advantage of in vivo electroporation is the ability to treat tissue in a local and minimally invasive fashion. The drawback is the current lack of control over the process. This paper is the first report of a new method for real-time three-dimensional imaging of an in vivo electroporation process. Using two needle electrodes for irreversible electroporation and a set of electrodes for reconstructing electrical impedance tomography (EIT) images of the treated tissue, we were able to demonstrate electroporation imaging in rodent livers. Histology analysis shows good correlation between the extent of tissue damage caused by irreversible electroporation and the EIT images. This new method may lead the way to real-time control over genetic treatment of diseases in tissue and tissue ablation.

  11. In vivo imaging of irreversible electroporation by means of electrical impedance tomography

    Science.gov (United States)

    Granot, Yair; Ivorra, Antoni; Maor, Elad; Rubinsky, Boris

    2009-08-01

    Electroporation, the increased permeability of cell membranes due to a large transmembrane voltage, is an important clinical tool. Both reversible and irreversible in vivo electroporation are used for clinical applications such as gene therapy and solid malignant tumor ablation, respectively. The primary advantage of in vivo electroporation is the ability to treat tissue in a local and minimally invasive fashion. The drawback is the current lack of control over the process. This paper is the first report of a new method for real-time three-dimensional imaging of an in vivo electroporation process. Using two needle electrodes for irreversible electroporation and a set of electrodes for reconstructing electrical impedance tomography (EIT) images of the treated tissue, we were able to demonstrate electroporation imaging in rodent livers. Histology analysis shows good correlation between the extent of tissue damage caused by irreversible electroporation and the EIT images. This new method may lead the way to real-time control over genetic treatment of diseases in tissue and tissue ablation.

  12. A derivation of a microscopic entropy and time irreversibility from the discreteness of time

    CERN Document Server

    Riek, Roland

    2014-01-01

    All of the basic microsopic physical laws are time reversible. In contrast, the second law of thermodynamics, which is a macroscopic physical representation of the world, is able to describe irreversible processes in an isolated system through the change of entropy S larger than 0. It is the attempt of the present manuscript to bridge the microscopic physical world with its macrosocpic one with an alternative approach than the statistical mechanics theory of Gibbs and Boltzmann. It is proposed that time is discrete with constant step size. Its consequence is the presence of time irreversibility at the microscopic level if the present force is of complex nature (i.e. not const). In order to compare this discrete time irreversible mechamics (for simplicity a classical, single particle in a one dimensional space is selected) with its classical Newton analog, time reversibility is reintroduced by scaling the time steps for any given time step n by the variable sn leading to the Nose-Hoover Lagrangian. The corresp...

  13. Optimal performance of a generalized irreversible four-reservoir isothermal chemical potential transformer

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A new cyclic model of a four-reservoir isothermal chemical potential transformer with irreversible mass transfer, mass leakage and internal dissipation is put forward in this paper. The optimal relation be-tween the coefficient of performance (COP) and the rate of energy pumping of the generalized irre-versible four-reservoir isothermal chemical potential transformer has been derived by using finite-time thermodynamics or thermodynamic optimization. The maximum COP and the corresponding rate of energy pumping, as well as the maximum rate of energy pumping and the corresponding COP, have been obtained. Moreover, the influences of the irreversibility on the optimal performance of the iso-thermal chemical potential transformer have been revealed. It was found that the mass leakage affects the optimal performance both qualitatively and quantitatively, while the internal dissipation affects the optimal performance quantitatively. The results obtained herein can provide some new theoretical guidelines for the optimal design and development of a class of isothermal chemical potential trans-formers, such as mass exchangers, electrochemical, photochemical and solid state devices, fuel pumps, etc.

  14. Optimal performance of a generalized irreversible four-reservoir isothermal chemical potential transformer

    Institute of Scientific and Technical Information of China (English)

    XIA Dan; CHEN LinGen; SUN FengRui

    2008-01-01

    A new cyclic model of a four-reservoir isothermal chemical potential transformer with irreversible mass transfer, mass leakage and internal dissipation is put forward in this paper. The optimal relation between the coefficient of performance (COP) and the rate of energy pumping of the generalized irreversible four-reservoir isothermal chemical potential transformer has been derived by using finite-time thermodynamics or thermodynamic optimization. The maximum COP and the corresponding rate of energy pumping, as well as the maximum rate of energy pumping and the corresponding COP, have been obtained. Moreover, the influences of the irreversibility on the optimal performance of the isothermal chemical potential transformer have been revealed. It was found that the mass leakage affects the optimal performance both qualitatively and quantitatively, while the internal dissipation affects the optimal performance quantitatively. The results obtained herein can provide some new theoretical guidelines for the optimal design and development of a class of isothermal chemical potential transformers, such as mass exchangers, electrochemical, photochemical and solid state devices, fuel pumps, etc.

  15. Magnetic irreversibility and relaxation in CuFe{sub 2}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Goya, G.F. E-mail: goya@macbeth.if.usp.br; Rechenberg, H.R.; Jiang, J.Z

    2000-08-01

    In this work, we present a study on the magnetic behavior of CuFe{sub 2}O{sub 4} nanoparticles with different particle sizes. Magnetic particle size distribution obtained from M(H) curves in the superparamagnetic (SPM) state showed good agreement with data obtained from X-ray powder diffraction. Field-cooled and zero-field-cooled magnetization data showed a blocking temperature T{sub B}{approx}225 K, independent of particle size, which is associated to interparticle interactions. It was observed that T{sub B} and the irreversibility temperature T{sub irr}, shift to lower temperature with increasing applied fields, both with an H{sup -1} dependence. Strong training effects were observed from relaxation data, assigned to the irreversible behavior of the spin-disordered particle surface. The magnetic viscosity at T=4.2 K was analyzed for sample with D{sub mean}=7.7 nm, revealing strong irreversibility after each major hysteresis loop. These results are discussed in terms of multiple spin-disordered configurations, at particle surface, with quasidegenerate states.

  16. Rules to transform concentrations and currents for irreversible reactions to those of quasireversible reactions

    International Nuclear Information System (INIS)

    Highlights: • Simple rules convert irreversible analytical solutions to quasireversible ones • These work for many common convective diffusion situations • Rules involve substitution of kf by kf + kb then scaling and constant addition • Irreversible numerical solutions can be converted to quasireversible ones - Abstract: Transformation rules are given that take the concentration or current expressions for the simple irreversible electron-transfer reaction R → P + e− and convert them to the corresponding quantities for the quasireversible reaction. They apply for many standard electrochemical mass-transport cases, including simple diffusion and convection-diffusion for the rotating disk or channel flow, provided that the diffusivities of the two species are equal. The forward rate constant is replaced by the sum of the forward and reverse rate constants, the result is scaled and then a constant added. Rules are also given for some cases where the diffusivities are unequal. As an application, a new solution of the concentration profile for a channel electrode within the Lévêque approximation neglecting axial diffusion is given

  17. Exergetic efficiency optimization for an irreversible heat pump working on reversed Brayton cycle

    Indian Academy of Sciences (India)

    Yuehong Bi; Lingen Chen; Fengrui Sun

    2010-03-01

    This paper deals with the performance analysis and optimization for irreversible heat pumps working on reversed Brayton cycle with constant-temperature heat reservoirs by taking exergetic efficiency as the optimization objective combining exergy concept with finite-time thermodynamics (FTT). Exergetic efficiency is defined as the ratio of rate of exergy output to rate of exergy input of the system. The irreversibilities considered in the system include heat resistance losses in the hot- and cold-side heat exchangers and non-isentropic losses in the compression and expansion processes. The analytical formulas of the heating load, coefficient of performance (COP) and exergetic efficiency for the heat pumps are derived. The results are compared with those obtained for the traditional heating load and coefficient of performance objectives. The influences of the pressure ratio of the compressor, the allocation of heat exchanger inventory, the temperature ratio of two reservoirs, the effectiveness of the hot- and cold-side heat exchangers and regenerator, the efficiencies of the compressor and expander, the ratio of hot-side heat reservoir temperature to ambient temperature, the total heat exchanger inventory, and the heat capacity rate of the working fluid on the exergetic efficiency of the heat pumps are analysed by numerical calculations. The results show that the exergetic efficiency optimization is an important and effective criterion for the evaluation of an irreversible heat pump working on reversed Brayton cycle.

  18. Endothelial dysfunction and atherosclerosis in children with irreversible pulmonary hypertension due to congenital heart disease

    International Nuclear Information System (INIS)

    To assess endothelial dysfunction and the risk for coronary atherosclerosis in children with irreversible pulmonary hypertension due to congenital heart disease (CHD). The study included 18 cyanotic patients (the mean age was 12.28 ± 3.26 years) who developed irreversible pulmonary hypertension due to cyanotic and acyanotic CHDs, and 18 control patients (the mean age was 11.78 ± 3.00 years). Study groups were compared for flow-mediated dilatation (FMD), carotid intima media thickness (CIMT) and atherosclerotic risk factors. Compared to the control group, the mean FMD was significantly reduced in the cyanotic group (5.26 ± 2.42% and 9.48 ± 2.60%, respectively; P-value < 0.001). No significant difference was observed between the groups in CIMT (0.41 ± 0.08 mm and 0.39 ± 0.06 mm, respectively; P-value = 0.299). The levels of total cholesterol, low-density lipoprotein–cholesterol and very low-density lipoprotein–cholesterol were statistically significantly lower compared tothe control group (P-value = 0.001, 0.006 and 0.014, respectively), whereas no statistically significant difference was found in the levels of high-density lipoprotein–cholesterol and triglycerides (P-value = 0.113 and 0.975, respectively). Systemic endothelial dysfunction in children with irreversible pulmonary hypertension due to CHD was noted but there was no increased risk for atherosclerosis

  19. Novel Selective and Irreversible Mosquito Acetylcholinesterase Inhibitors for Controlling Malaria and Other Mosquito-Borne Diseases

    Science.gov (United States)

    Dou, Dengfeng; Park, Jewn Giew; Rana, Sandeep; Madden, Benjamin J.; Jiang, Haobo; Pang, Yuan-Ping

    2013-01-01

    We reported previously that insect acetylcholinesterases (AChEs) could be selectively and irreversibly inhibited by methanethiosulfonates presumably through conjugation to an insect-specific cysteine in these enzymes. However, no direct proof for the conjugation has been published to date, and doubts remain about whether such cysteine-targeting inhibitors have desirable kinetic properties for insecticide use. Here we report mass spectrometric proof of the conjugation and new chemicals that irreversibly inhibited African malaria mosquito AChE with bimolecular inhibition rate constants (kinact/KI) of 3,604-458,597 M-1sec-1 but spared human AChE. In comparison, the insecticide paraoxon irreversibly inhibited mosquito and human AChEs with kinact/KI values of 1,915 and 1,507 M-1sec-1, respectively, under the same assay conditions. These results further support our hypothesis that the insect-specific AChE cysteine is a unique and unexplored target to develop new insecticides with reduced insecticide resistance and low toxicity to mammals, fish, and birds for the control of mosquito-borne diseases.

  20. Irreversibilities and efficiency at maximum power of heat engines: the illustrative case of a thermoelectric generator.

    Science.gov (United States)

    Apertet, Y; Ouerdane, H; Goupil, C; Lecoeur, Ph

    2012-03-01

    Energy conversion efficiency at maximum output power, which embodies the essential characteristics of heat engines, is the main focus of the present work. The so-called Curzon and Ahlborn efficiency η(CA) is commonly believed to be an absolute reference for real heat engines; however, a different but general expression for the case of stochastic heat engines, η(SS), was recently found and then extended to low-dissipation engines. The discrepancy between η(CA) and η(SS) is here analyzed considering different irreversibility sources of heat engines, of both internal and external types. To this end, we choose a thermoelectric generator operating in the strong-coupling regime as a physical system to qualitatively and quantitatively study the impact of the nature of irreversibility on the efficiency at maximum output power. In the limit of pure external dissipation, we obtain η(CA), while η(SS) corresponds to the case of pure internal dissipation. A continuous transition between from one extreme to the other, which may be operated by tuning the different sources of irreversibility, also is evidenced.

  1. Ultraviolet-induced irreversible tensile actuation of diacetylene/nylon microfibers

    Science.gov (United States)

    Chun, Kyoung-Yong; Choi, Changsoon; Baughman, Ray H.; Kim, Seon Jeong

    2016-07-01

    Photomechanically irreversible tensile-actuated diacetylene-embedding nylon 6/6 microfibers were investigated. 10,12-pentacosadiynoic acid (PCDA) monomer, which have conventionally provided a visual color change by temperature and photo-driven stimuli, was embedded in nylon 6/6 microfibers by wet spinning. By ultraviolet (UV) (254 nm) exposure, we observed irreversible tensile actuation (contraction) of linear (untwisted) and helical (twisted) structural microfibers. The tensile contraction of twisted nylon 6/6-PCDA microfiber containing10 mM PCDA was reached to ∼2% at 60 °C. Such irreversible tensile contraction can be promoted by volume contraction of PCDA monomers during UV exposure along with irregular structural deformation containing gauche conformation with increasing temperature. The kinetics of tensile contraction with temperature and time were shown by the Arrhenius plots. The activation energies were 34.3–35.7 kJ mol‑1 as increasing the concentration of PCDA, implies that the nylon 6/6-PCDA microfibers could be applied to show time-temperature integrated device.

  2. Understanding Irreversible Degradation of Nb3Sn Wires with Fundamental Fracture Mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Yuhu [PPPL; Calzolaio, Ciro [Univ of Geneva; Senatore, Carmine [Univ of Geneva

    2014-08-01

    Irreversible performance degradation of advanced Nb3Sn superconducting wires subjected to transverse or axial mechanical loading is a critical issue for the design of large-scale fusion and accelerator magnets such as ITER and LHC. Recent SULTAN tests indicate that most cable-in-conduit conductors for ITER coils made of Nb3Sn wires processed by various fabrication techniques show similar performance degradation under cyclic loading. The irreversible degradation due to filament fracture and local strain accumulation in Nb3Sn wires cannot be described by the existing strand scaling law. Fracture mechanic modeling combined with X-ray diffraction imaging of filament micro-crack formation inside the wires under mechanical loading may reveal exciting insights to the wire degradation mechanisms. We apply fundamental fracture mechanics with a singularity approach to study influence of wire filament microstructure of initial void size and distribution to local stress concentration and potential crack propagation. We report impact of the scale and density of the void structure on stress concentration in the composite wire materials for crack initiation. These initial defects result in an irreversible degradation of the critical current beyond certain applied stress. We also discuss options to minimize stress concentration in the design of the material microstructure for enhanced wire performance for future applications.

  3. Concerning the study of the irreversible magnetic behaviour of superconductivity; Contribution a l'etude du comportement magnetique irreversible des supraconducteurs

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, G. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1965-03-01

    The influence of the presence of extended lattice defects on the magnetic behaviour has been studied for the case of type I superconductors, such as Re and Ta, and in a more quantitative manner for the type II superconductor niobium. In this case, measurements of the thermal conductivity have given an estimate of the relative concentration of lattice defects in each specimen. These measurements show that the larger the number of lattice defects, the more irreversible becomes the magnetization curve, and the larger becomes the values of the critical current, which is related by a simple model to the magnetization values. Finally, a study by transmission electron microscopy has confirmed on the one hand the diversity of the extended lattice defects and on the other hand has allowed the formulation of several hypothesis on their respective influence. [French] L'influence de la presence de defauts etendus sur le comportement magnetique a ete etudie pour des supraconducteurs de premiere espece, tels que le rhenium et le tantale, et plus quantitativement pour un supraconducteur de deuxieme espece, le niobium. Dans ce cas, des mesures de conductibilite thermique ont permis d'estimer la concentration relative des defauts du reseau dans chaque echantillon. Ces mesures montrent que plus les defauts du reseau sont nombreux, plus la courbe d'aimantation est irreversible, et plus les valeurs du courant critique, reliees par un modele simple aux valeurs de l'aimantation, sont elevees. Enfin une etude par microscopie electronique en transmission - a permis d'une part de constater la diversite des defauts etendus et d'autre part de formuler quelques hypotheses sur leurs influences respectives.

  4. Por que sou rondoniano

    Directory of Open Access Journals (Sweden)

    Mércio Pereira Gomes

    2009-01-01

    Full Text Available Numa revisão contextualizada no tempo e projetada pelos seus resultados, a obra do sertanista marechal Cândido Rondon (1867-1958 é avaliada positivamente pela dedicação à causa dos povos indígenas do Brasil, pela formação de uma ética de respeito do brasileiro para com os índios e pela institucionalização do dever do Estado brasileiro de proteger, assistir e ajudar os povos indígenas a manterem-se coesos e autônomos e ao mesmo tempo se projetarem no mundo mais amplo. A vida de Rondon é acompanhada desde a sua formação como cadete da Escola Militar, como membro da Igreja do Apostolado Positivista, como comandante da Expedição Rondon (1907-1930, que levou o telégrafo de Cuiabá a Porto Velho, e especialmente como criador e dirigente-mor do Serviço de Proteção aos Índios (SPI, 1910-1967. Rondon é o criador da expressão "Morrer se preciso for, matar nunca", que pautou a ação de indigenistas brasileiros que fizeram os primeiros contatos com muitos povos indígenas desde 1910. E muitos morreram seguindo essa norma, numa clara demonstração do novo espírito humanista criado pela atitude rondoniana. O indigenismo brasileiro implantado por Rondon teve altos e baixos ao longo de quase cem anos, que hoje prossegue pela Fundação Nacional do Índio (Funai. De fato, muitos povos indígenas perderam suas terras e muitos foram dizimados no século XX, mas os mais de 220 que sobreviveram vêm crescendo em número, obtendo suas terras (13% do território nacional e conquistando novos espaços político-culturais no Brasil.This paper reviews the life and work of Brazilian Indianist Marshall Cândido Rondon. Rondon's life is marked by a profound dedication to the Brazilian Indian cause and to instilling in Brazilians a respect for Indian peoples. He influenced the Brazilian government in shaping a policy of protecting, assisting, and helping Indian peoples retain cohesive, self-determined societies. He also encouraged Indians to

  5. Porøse materialer

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place

    2000-01-01

    Dette undervisningsnotat er en samling af noter, der refererer til den indledende del af kurset Materialmekanik og Porøse materailer på Insitut for Bærende Konstruktiner og Materialer (BKM).......Dette undervisningsnotat er en samling af noter, der refererer til den indledende del af kurset Materialmekanik og Porøse materailer på Insitut for Bærende Konstruktiner og Materialer (BKM)....

  6. The Thermodynamic Continuum of Jet Engine Performance: The Principle of Lost Work due to Irreversibility in Aerospace Systems

    OpenAIRE

    David Riggins

    2003-01-01

    The performance continuum for air-breathing engines is formally developed and illustrated in terms of fundamental thermodynamic quantities including heat and work interactions and the irreversibility occurring in the flow-path of the engine. The thermodynamically consistent base-line from which performance losses due to irreversibility must be measured is clearly defined based on this analysis. Issues and problems with conventional flow availability (flow exergy) in terms of the assessment (d...

  7. On the implication of environmental policy on growth in an OLG model with pollution permits and potential irreversible pollution

    OpenAIRE

    Jean-Marie, Alain; Prieur, Fabien; Tidball, Mabel; European Association of Environmental and Resource Economists

    2007-01-01

    We consider an OLG model with emissions arising from production and potential irreversible pollution. Pollution control goes through a system of permits and private agents can also maintain the environment. In this setting, we prove that there exist multiple equilibria. Due to the possible irreversibility, the economy can be dragged into both stationary and asymptotic poverty traps. First, we show that choosing a global quota on emissions at the lowest level beyond a critical threshold is a m...

  8. On the implication of environmental policy on growth in an OLG model with pollution permits and potential irreversible pollution

    OpenAIRE

    Jean-Marie, Alain; Prieur, Fabien; Tidball, Mabel

    2007-01-01

    International audience This paper develops an OLG model with emissions arising from production and potential irreversible pollution. Pollution control goes through a system of permits and private agents can also maintain the environment. In this setting, we prove that there exist multiple equilibria. Due to the possible irreversibility, the economy can be dragged into both stationary and asymptotic poverty traps. First, we show that choosing a global quota on emissions at the lowest level ...

  9. ON THE IMPLICATION OF ENVIRONMENTAL POLICY ON GROWTH IN AN OLG MODEL WITH POLLUTION PERMITS AND IRREVERSIBLE POLLUTION

    OpenAIRE

    Alain Jean-Marie; Fabien Prieur; Mabel Tidball

    2007-01-01

    This paper develops an OLG model with emissions arising from production and potential irreversible pollution. Pollution control goes through a system of permits and private agents can also maintain the environment. In this setting, we prove that there exist multiple equilibria. Due to the possible irreversibility, the economy can be dragged into both stationary and asymptotic poverty traps. First, we show that choosing a global quota on emissions at the lowest level beyond a critical threshol...

  10. Endothelial dysfunction and atherosclerosis in children with irreversible pulmonary hypertension due to congenital heart disease

    Directory of Open Access Journals (Sweden)

    Murat Çiftel

    2012-01-01

    Full Text Available Objective: To assess endothelial dysfunction and the risk for coronary atherosclerosis in children with irreversible pulmonary hypertension due to congenital heart disease (CHD. Methods: The study included 18 cyanotic patients (the mean age was 12.28 ± 3.26 years who developed irreversible pulmonary hypertension due to cyanotic and acyanotic CHDs, and 18 control patients (the mean age was 11.78 ± 3.00 years. Study groups were compared for flow-mediated dilatation (FMD, carotid intima media thickness (CIMT and atherosclerotic risk factors. Results: Compared to the control group, the mean FMD was significantly reduced in the cyanotic group (5.26 ± 2.42% and 9.48 ± 2.60%, respectively; P-value < 0.001. No significant difference was observed between the groups in CIMT (0.41 ± 0.08 mm and 0.39 ± 0.06 mm, respectively; P-value = 0.299. The levels of total cholesterol, low-density lipoprotein-cholesterol and very low-density lipoprotein-cholesterol were statistically significantly lower compared tothe control group (P-value = 0.001, 0.006 and 0.014, respectively, whereas no statistically significant difference was found in the levels of high-density lipoprotein-cholesterol and triglycerides (P-value = 0.113 and 0.975, respectively. Conclusions: Systemic endothelial dysfunction in children with irreversible pulmonary hypertension due to CHD was noted but there was no increased risk for atherosclerosis.

  11. The anti-inflammatory effects of matrix metalloproteinase-3 on irreversible pulpitis of mature erupted teeth.

    Directory of Open Access Journals (Sweden)

    Hisanori Eba

    Full Text Available Matrix metalloproteinases (MMPs are involved in extracellular matrix degradation and the modulation of cell behavior. These proteinases have also been implicated in tissue repair and regeneration. Our previous studies have demonstrated that MMP-3 elicits stimulatory effects on the proliferation and the migration of endothelial cells as well as anti-apoptotic effects on these cells in vitro. In addition, we found that MMP-3 enhanced the regeneration of lost pulp tissue in a rat incisor pulp injury model. However, continuously erupting rodent incisors exhibit significantly different pulp organization compared with mature erupted teeth. Therefore, we have further extended these studies using a canine irreversible pulpitis model to investigate the effects of MMP-3. In this study, the crowns of the canine mature premolars were removed and the pulp tissues were amputated. The amputated pulp tissues remained exposed for 24 or 72 hours to induce mild or severe irreversible pulpitis, respectively, followed by sealing of the cavities. In both models, the whole pulp tissues became necrotic by day 14. In this mild pulpitis model, the regeneration of pulp tissue with vasculature and nerves was observed until 14 days after sealing with MMP-3, followed by extracellular matrix formation in the regenerated pulp tissues until day 28. The treatment with MMP-3 resulted in a decrease in the number of macrophage and antigen-presenting cells and a significant inhibition of IL-6 expression on day 3. The inhibition of MMP-3 activity abolished these anti-inflammatory effects. Immunofluorescence staining demonstrated that MMP-3 was involved in the modification of serum-derived hyaluronan-associated proteins and hyaluronan (SHAP-HA complexes possibly through the degradation of versican. These results demonstrate that MMP-3 can act as an anti-inflammatory agent and suggest that MMP-3 might represent a useful therapy for the treatment of mild irreversible pulpitis.

  12. A Derivation of a Microscopic Entropy and Time Irreversibility From the Discreteness of Time

    Directory of Open Access Journals (Sweden)

    Roland Riek

    2014-06-01

    Full Text Available The basic microsopic physical laws are time reversible. In contrast, the second law of thermodynamics, which is a macroscopic physical representation of the world, is able to describe irreversible processes in an isolated system through the change of entropy ΔS > 0. It is the attempt of the present manuscript to bridge the microscopic physical world with its macrosocpic one with an alternative approach than the statistical mechanics theory of Gibbs and Boltzmann. It is proposed that time is discrete with constant step size. Its consequence is the presence of time irreversibility at the microscopic level if the present force is of complex nature (F(r ≠ const. In order to compare this discrete time irreversible mechamics (for simplicity a “classical”, single particle in a one dimensional space is selected with its classical Newton analog, time reversibility is reintroduced by scaling the time steps for any given time step n by the variable sn leading to the Nosé-Hoover Lagrangian. The corresponding Nos´e-Hoover Hamiltonian comprises a term Ndf kB T ln sn (kB the Boltzmann constant, T the temperature, and Ndf the number of degrees of freedom which is defined as the microscopic entropy Sn at time point n multiplied by T. Upon ensemble averaging this microscopic entropy Sn in equilibrium for a system which does not have fast changing forces approximates its macroscopic counterpart known from thermodynamics. The presented derivation with the resulting analogy between the ensemble averaged microscopic entropy and its thermodynamic analog suggests that the original description of the entropy by Boltzmann and Gibbs is just an ensemble averaging of the time scaling variable sn which is in equilibrium close to 1, but that the entropy

  13. Nanostructure and irreversible colloidal behavior of Ca(OH)2: implications in cultural heritage conservation.

    Science.gov (United States)

    Rodriguez-Navarro, C; Ruiz-Agudo, E; Ortega-Huertas, M; Hansen, E

    2005-11-22

    Although Ca(OH)2 is one of the oldest art and building material used by mankind, little is known about its nanostructural and colloidal characteristics that play a crucial role in its ultimate performance as a binder in lime mortars and plasters. In particular, it is unknown why hydrated lime putty behaves as an irreversible colloid once dried. Such effect dramatically affects the reactivity and rheology of hydrated lime dispersions. Here we show that the irreversible colloidal behavior of Ca(OH)2 dispersions is the result of an oriented aggregation mechanism triggered by drying. Kinetic stability and particle size distribution analysis of oven-dried slaked lime or commercial dry hydrate dispersions exhibit a significant increase in settling speed and particle (cluster) size in comparison to slaked lime putty that has never been dried. Drying-related particle aggregation also leads to a significant reduction in surface area. Electron microscopy analyses show porous, randomly oriented, micron-sized clusters that are dominant in the dispersions both before and after drying. However, oriented aggregation of the primary Ca(OH)2 nanocrystals (approximately 60 nm in size) is also observed. Oriented aggregation occurs both before and during drying, and although limited before drying, it is extensive during drying. Nanocrystals self-assemble in a crystallographically oriented manner either along the 100 or equivalent 110 directions, or along the Ca(OH)2 basal planes, i.e., along [001]. While random aggregation appears to be reversible, oriented aggregation is not. The strong coherent bonding among oriented nanoparticles prevents disaggregation upon redispersion in water. The observed irreversible colloidal behavior associated with drying of Ca(OH)2 dispersions has important implications in heritage conservation, particularly considering that nowadays hydrated lime is often the preferred alternative to portland cement in architectural heritage conservation. Finally, our

  14. Efficiency at maximum power output of linear irreversible Carnot-like heat engines.

    Science.gov (United States)

    Wang, Yang; Tu, Z C

    2012-01-01

    The efficiency at maximum power output of linear irreversible Carnot-like heat engines is investigated based on the assumption that the rate of irreversible entropy production of the working substance in each "isothermal" process is a quadratic form of the heat exchange rate between the working substance and the reservoir. It is found that the maximum power output corresponds to minimizing the irreversible entropy production in two isothermal processes of the Carnot-like cycle, and that the efficiency at maximum power output has the form η(mP)=η(C)/(2-γη(C)), where η(C) is the Carnot efficiency, while γ depends on the heat transfer coefficients between the working substance and two reservoirs. The value of η(mP) is bounded between η(-)≡η(C)/2 and η(+)≡η(C)/(2-η(C)). These results are consistent with those obtained by Chen and Yan [J. Chem. Phys. 90, 3740 (1989)] based on the endoreversible assumption, those obtained by Esposito et al. [Phys. Rev. Lett. 105, 150603 (2010)] based on the low-dissipation assumption, and those obtained by Schmiedl and Seifert [Europhys. Lett. 81, 20003 (2008)] for stochastic heat engines which in fact also satisfy the low-dissipation assumption. Additionally, we find that the endoreversible assumption happens to hold for Carnot-like heat engines operating at the maximum power output based on our fundamental assumption, and that the Carnot-like heat engines that we focused on do not strictly satisfy the low-dissipation assumption, which implies that the low-dissipation assumption or our fundamental assumption is a sufficient but non-necessary condition for the validity of η(mP)=η(C)/(2-γη(C)) as well as the existence of two bounds, η(-)≡η(C)/2 and η(+)≡η(C)/(2-η(C)).

  15. Parametric analysis of an irreversible proton exchange membrane fuel cell/absorption refrigerator hybrid system

    International Nuclear Information System (INIS)

    A hybrid system mainly consisting of a PEMFC (proton exchange membrane fuel cell) and an absorption refrigerator is proposed, where the PEMFC directly converts the chemical energy contained in the hydrogen into electrical and thermal energies, and the thermal energy is transferred to drive the bottoming absorption refrigerator for cooling purpose. By considering the existing irreversible losses in the hybrid system, the operating current density region of the PEMFC permits the absorption refrigerator to exert its function is determined and the analytical expressions for the equivalent power output and efficiency of the hybrid system under different operating conditions are specified. Numerical calculations show that the equivalent maximum power density and the corresponding efficiency of the hybrid system can be respectively increased by 5.3% and 6.8% compared to that of the stand-alone PEMFC. Comprehensive parametric analyses are conducted to reveal the effects of the internal irreversibility of the absorption refrigerator, operating current density, operating temperature and operating pressure of the PEMFC, and some integrated parameters related to the thermodynamic losses on the performance of the hybrid system. The model presented in the paper is more general than previous study, and the results for some special cases can be directly derived from this paper. - Highlights: • A CHP system composed of a PEMFC and an absorption refrigerator is proposed. • Current density region enables the absorption refrigerator to work is determined. • Multiple irreversible losses in the system are analytically characterized. • Maximum power density and corresponding efficiency can be increased by 5.3% and 6.8%. • Effects of some designing and operating parameters on the performance are discussed

  16. Step-by-Step Technique for Irreversible Electroporation of Focal Prostate Cancer: An Instructional Video Guide.

    Science.gov (United States)

    Ting, Francis; Van Leeuwen, Pim J; Stricker, Phillip D

    2016-04-01

    Focal therapy has emerged as a tissue-sparing treatment modality for selected men with low to intermediate volume, localized prostate cancer with the advantage of reducing treatment morbidity because of preservation of untreated prostate tissue and surrounding structures. Irreversible electroporation is an emerging interventional focal therapy modality that uses high voltage electrical fields to induce cell death. This instructional video guide (Fig) serves as an easy-to-understand, comprehensive educational tool so that a broader audience can gain an understanding of the techniques involved in this treatment modality. PMID:27013005

  17. Percutaneous Irreversible Electroporation of Unresectable Hilar Cholangiocarcinoma (Klatskin Tumor): A Case Report

    International Nuclear Information System (INIS)

    Irreversible electroporation (IRE) is a novel image-guided ablation technique that is rapidly gaining popularity in the treatment of malignant tumors located near large vessels or bile ducts. The presence of metal objects in the ablation zone, such as Wallstents, is generally considered a contraindication for IRE, because tissue heating due to power conduction may lead to thermal complications. This report describes a 66-year-old female with a Bismuth–Corlette stage IV unresectable cholangiocarcinoma with a metallic Wallstent in the common bile duct, who was safely treated with percutaneous IRE with no signs for relapse 1 year after the procedure

  18. Percutaneous Irreversible Electroporation of Unresectable Hilar Cholangiocarcinoma (Klatskin Tumor): A Case Report.

    Science.gov (United States)

    Melenhorst, Marleen C A M; Scheffer, Hester J; Vroomen, Laurien G P H; Kazemier, Geert; van den Tol, M Petrousjka; Meijerink, Martijn R

    2016-01-01

    Irreversible electroporation (IRE) is a novel image-guided ablation technique that is rapidly gaining popularity in the treatment of malignant tumors located near large vessels or bile ducts. The presence of metal objects in the ablation zone, such as Wallstents, is generally considered a contraindication for IRE, because tissue heating due to power conduction may lead to thermal complications. This report describes a 66-year-old female with a Bismuth-Corlette stage IV unresectable cholangiocarcinoma with a metallic Wallstent in the common bile duct, who was safely treated with percutaneous IRE with no signs for relapse 1 year after the procedure. PMID:25994516

  19. The Effect of Blood Flow on Magnetic Resonance Imaging of Non Thermal Irreversible Electroporation

    OpenAIRE

    Mohammad Hjouj; Jacob Lavee; David Last; David Guez; Dianne Daniels; Shirley Sharabi; Boris Rubinsky; Yael Mardor

    2013-01-01

    To generate an understanding of the physiological significance of MR images of Non-Thermal Irreversible Electroporation (NTIRE) we compared the following MR imaging sequences: T1W, T2W, PD, GE, and T2 SPAIR acquired after NTIRE treatment in a rodent liver model. The parameters that were studied included the presence or absence of a Gd-based contrast agent, and in vivo and ex-vivo NTIRE treatments in the same liver. NTIRE is a new minimally invasive tissue ablation modality in which pulsed ele...

  20. Nonlinear Constants of Quantum Information in Reversible and Irreversible Amplitude Flows

    CERN Document Server

    Qian, Xiao-Feng

    2010-01-01

    We report an approach to quantum open system dynamics that leads to novel nonlinear constant relations governing information flow among the participants. Our treatment is for mixed state systems entangled in a pure state fashion with an unspecified party that was involved in preparing the system for an experimental test, but no longer interacts after $t=0$. Evolution due to subsequent interaction with another party is treated as an amplitude flow channel and uses Schmidt-type bipartite decomposition of the evolving state. We illustrate this with three examples, including both reversible and irreversible information flows, and give formulas for the new nonlinear constraints in each case.

  1. Irreversible thermochromic response of RF sputtered nanocrystalline BaWO4 films for smart window applications

    OpenAIRE

    C. Anil Kumar; T. Santhosh Kumar; D. Pamu

    2015-01-01

    We report irreversible thermochromic behaviour of BaWO4 (BWO) films for the first time. BWO films have been deposited at different substrate temperatures (RT, 200, 400, 600 and 800 °C) using RF magnetron sputtering in pure argon plasma. BWO films deposited at 800 °C exhibit crystalline nature. Also, BWO films deposited in the temperature range of 400 - 600 °C exhibit WO3 as a secondary phase and its weight percentage decreases with an increase in deposition temperature, whereas the films depo...

  2. The performance characteristics of an irreversible quantum Otto harmonic refrigeration cycle

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper, an irreversible quantum Otto refrigeration cycle working with harmonic systems is established. Base on Heisenberg quantum master equation, the equations of motion for the set of harmonic systems thermodynamic observables are derived. The simulated diagrams of the quantum Otto refrigeration cycle are plotted. The relationship between average power of friction, cooling rate, power input, and the time of adiabatic process is analyzed by using numerical calculation. Moreover, the influence of the heat conductance and the time of iso-frequency process on the performance of the cycle is discussed.

  3. The performance characteristics of an irreversible quantum Otto harmonic refrigeration cycle

    Institute of Scientific and Technical Information of China (English)

    HE JiZhou; HE Xian; TANG Wei

    2009-01-01

    In this paper,an irreversible quantum Otto refrigeration cycle working with harmonic systems is estab-lished.Base on Heisenberg quantum master equation,the equations of motion for the set of harmonic systems thermodynamic observables are derived.The simulated diagrams of the quantum Otto refrig-eration cycle are plotted.The relationship between average power of friction,cooling rate,power input,and the time of adiabatic process is analyzed by using numerical calculation.Moreover,the influence of the heat conductance and the time of iso-frequency process on the performance of the cycle is dis-cussed.

  4. Efficiency at maximum power output of an irreversible Carnot-like cycle with internally dissipative friction.

    Science.gov (United States)

    Wang, Jianhui; He, Jizhou

    2012-11-01

    We investigate the efficiency at the maximum power output (EMP) of an irreversible Carnot engine performing finite-time cycles between two reservoirs at constant temperatures T(h) and T(c) (Carnot efficiency, whether the internally dissipative friction is considered or not. When dissipations of two "isothermal" and two "adiabatic" processes are symmetric, respectively, and the time allocation between the adiabats and the contact time with the reservoir satisfy a certain relation, the Curzon-Ahlborn (CA) efficiency η(CA) = 1-sqrt[T(c)/T(h)] is derived.

  5. Analysis of a quantum irreversible Otto cycle with exergetic sustainable index

    Science.gov (United States)

    Dalkıran, Alper; Açıkkalp, Emin; Caner, Necmettin

    2016-07-01

    In this study, exergetic sustainability index is applied to quantum irreversible Otto cycle with -1/2 spin system. Exergetic sustainability index in a quantum engine is used first time. This index is the ratio of exergy output (work output for a thermal engine) to total exergetic losses. It gives an opportunity to evaluate for all thermodynamic losses in the system, that is why, it is an important index. In addition, some thermodynamic parameters (work output, exergy destruction, first and second law efficiencies) are considered and their relationships between the exergetic sustainability index are determined.

  6. Statistical mechanics out of equilibrium the irreversibility; Mecanica estadistica fuera del equilibrio debate sobre la irreversibilidad

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez Estrada, R. F.

    2001-07-01

    A Round Table about the issue of Irreversibility and related matters has taken place during the last (20th) Statistical Mechanics Conference, held in Paris (July 1998). This article tries to provide a view (necessarily limited, and hence, uncompleted) of some approaches to the subject: the one based upon deterministic chaos (which is currently giving rise to a very active research) and the classical interpretation due to Boltzmann. An attempt has been made to write this article in a self-contained way, and to avoid a technical presentation wherever possible. (Author) 29 refs.

  7. Irreversible thermochromic behavior in gold and silver nanorod/polymeric ionic liquid nanocomposite films.

    Science.gov (United States)

    Tollan, Christopher M; Marcilla, Rebeca; Pomposo, Jose A; Rodriguez, Javier; Aizpurua, Javier; Molina, Jon; Mecerreyes, David

    2009-02-01

    The novel application of gold and silver nanorods as irreversible thermochromic dyes in polymeric ionic liquid (PIL) nanocomposites is proposed here. These materials have been synthesized by anion exchange of an imidazolium-based PIL in a solution that also contained gold nanorods. This resulted in the entrapment of the nanoobjects within a solid polymer precipitate. In this article, the effect of the temperature was studied in relation to the change of shape and, consequently, color of the gold or silver nanorods within the films. For the nanocomposites studied here, a maximum of two visual thermochromic transitions was observed for gold nanorods and up to three transitions were observed for silver nanorods.

  8. Percutaneous Irreversible Electroporation of Unresectable Hilar Cholangiocarcinoma (Klatskin Tumor): A Case Report.

    Science.gov (United States)

    Melenhorst, Marleen C A M; Scheffer, Hester J; Vroomen, Laurien G P H; Kazemier, Geert; van den Tol, M Petrousjka; Meijerink, Martijn R

    2016-01-01

    Irreversible electroporation (IRE) is a novel image-guided ablation technique that is rapidly gaining popularity in the treatment of malignant tumors located near large vessels or bile ducts. The presence of metal objects in the ablation zone, such as Wallstents, is generally considered a contraindication for IRE, because tissue heating due to power conduction may lead to thermal complications. This report describes a 66-year-old female with a Bismuth-Corlette stage IV unresectable cholangiocarcinoma with a metallic Wallstent in the common bile duct, who was safely treated with percutaneous IRE with no signs for relapse 1 year after the procedure.

  9. Robust and Irreversible Development in Cell Society as a General Consequence of Intra-Inter Dynamics

    CERN Document Server

    Kaneko, K; Kaneko, Kunihiko; Furusawa, Chikara

    1999-01-01

    A dynamical systems scenario for developmental cell biology is proposed, based on numerical studies of a system with interacting units with internal dynamics and reproduction. Diversification, formation of discrete and recursive types, and rules for differentiation are found as a natural consequence of such a system. "Stem cells" that either proliferate or differentiate to different types stochastically are found to appear when intra-cellular dynamics are chaotic. Robustness of the developmental process against microscopic and macroscopic perturbations is shown to be a natural consequence of such intra-inter dynamics, while irreversibility in developmental process is discussed in terms of the gain of stability, loss of diversity and chaotic instability.

  10. Percutaneous Irreversible Electroporation of Unresectable Hilar Cholangiocarcinoma (Klatskin Tumor): A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Melenhorst, Marleen C. A. M., E-mail: m.melenhorst@vumc.nl; Scheffer, Hester J., E-mail: hj.scheffer@vumc.nl; Vroomen, Laurien G. P. H., E-mail: la.vroomen@vumc.nl [VU University Medical Center, Department of Radiology and Nuclear Medicine (Netherlands); Kazemier, Geert, E-mail: g.kazemier@vumc.nl; Tol, M. Petrousjka van den, E-mail: mp.vandentol@vumc.nl [VU University Medical Center, Department of Surgery (Netherlands); Meijerink, Martijn R., E-mail: mr.meijerink@vumc.nl [VU University Medical Center, Department of Radiology and Nuclear Medicine (Netherlands)

    2016-01-15

    Irreversible electroporation (IRE) is a novel image-guided ablation technique that is rapidly gaining popularity in the treatment of malignant tumors located near large vessels or bile ducts. The presence of metal objects in the ablation zone, such as Wallstents, is generally considered a contraindication for IRE, because tissue heating due to power conduction may lead to thermal complications. This report describes a 66-year-old female with a Bismuth–Corlette stage IV unresectable cholangiocarcinoma with a metallic Wallstent in the common bile duct, who was safely treated with percutaneous IRE with no signs for relapse 1 year after the procedure.

  11. Low voltage irreversible electroporation induced apoptosis in HeLa cells

    Directory of Open Access Journals (Sweden)

    Wei Zhou

    2012-01-01

    Full Text Available Background: High-voltage electric field pulses can make cell membrane electroporated irreversibly and eliminate malignant cells via necrosis. However, low-voltage is not efficient as that. Aims: This study determined the differential effects of high- and low-voltage electric field pulses on HeLa cells, when the power of low-voltage was enhanced by increasing quantity of pulses. Materials and Methods: Pulses electric fields with permanent frequency (1 Hz and pulse length (100 μs were performed on HeLa cells. Voltage and pulse sets (8 pulses/set were various during treatment. CCK-8 assay was used to detect cell viability. The quantitative determination of apoptosis and necrosis were performed by flow cytometry with Annexin V and PI staining. Transmission electron microscopy was used to observe the ultrastructure of HeLa cells. Caspase-3 and caspase-8, the enzymes in apoptotic pathway, were determined by western blot. Results: The data showed that low-voltage electric field pulses also could make cell irreversible electroporation (IRE and ablate HeLa cells effectively by induction of apoptosis. The ablating effect due to low-voltage treatments delivered with a greater number of pulses may be as satisfactory as high-voltage, or even preferable because it causes less necrosis and more apoptosis. Conclusions: IRE induced by low voltage with more pulses could ablate HeLa cells effectively as high voltage, and it was preferable that less necrosis and more apoptosis occurred under such condition.

  12. An Efficient Site-Specific Method for Irreversible Covalent Labeling of Proteins with a Fluorophore.

    Science.gov (United States)

    Liu, Jiaquan; Hanne, Jeungphill; Britton, Brooke M; Shoffner, Matthew; Albers, Aaron E; Bennett, Jared; Zatezalo, Rachel; Barfield, Robyn; Rabuka, David; Lee, Jong-Bong; Fishel, Richard

    2015-01-01

    Fluorophore labeling of proteins while preserving native functions is essential for bulk Förster resonance energy transfer (FRET) interaction and single molecule imaging analysis. Here we describe a versatile, efficient, specific, irreversible, gentle and low-cost method for labeling proteins with fluorophores that appears substantially more robust than a similar but chemically distinct procedure. The method employs the controlled enzymatic conversion of a central Cys to a reactive formylglycine (fGly) aldehyde within a six amino acid Formylglycine Generating Enzyme (FGE) recognition sequence in vitro. The fluorophore is then irreversibly linked to the fGly residue using a Hydrazinyl-Iso-Pictet-Spengler (HIPS) ligation reaction. We demonstrate the robust large-scale fluorophore labeling and purification of E.coli (Ec) mismatch repair (MMR) components. Fluorophore labeling did not alter the native functions of these MMR proteins in vitro or in singulo. Because the FGE recognition sequence is easily portable, FGE-HIPS fluorophore-labeling may be easily extended to other proteins. PMID:26582263

  13. Irreversible Aspects of Continuum Mechanics and Transfer of Physical Characteristics in Moving Fluids : Symposia

    CERN Document Server

    Sedov, L

    1968-01-01

    At its meeting on April 23, 1965 in Paris the Bureau of IUTAM decided to have a Symposium on the Irreversible Aspects of Continaum Mechanics held in June 1966 in Vienna. In addition, a Symposium on the Transfer of Physical Characteristics in Moving Fluids which, orig­ inally, had been scheduled to take place in Stockholm was rescheduled to be held in Vienna immediately following the Symposium on the Irre­ versible Aspects of Continuum Mechanics. It was felt that the subjects of the two symposia were so closely related that participants should be given an opportunity to attend both. Both decisions were unanimously approved by the members of the General Assembly of IUTAM. Prof. H. PARKUS, Vienna, was appointed Chairman of the Symposium on the Irreversible Aspects, and Prof. L. I. SEDOV, Moscow, was appointed Chairman of the Symposium on the Transfer of Physical Characteristics, with Prof. P ARKUS being re­ sponsible for the local organization of both symposia. In accordance with the policy set forth by IUTAM...

  14. Synthesis and characterization of diazomethylarachidonyl ketone: an irreversible inhibitor of N-arachidonylethanolamine amidohydrolase.

    Science.gov (United States)

    Edgemond, W S; Greenberg, M J; McGinley, P J; Muthian, S; Campbell, W B; Hillard, C J

    1998-07-01

    N-Arachidonylethanolamine (AEA), a putative endogenous agonist of neuronal (CB1) cannabinoid receptors, is a substrate for N-arachidonylethanolamine amidohydrolase (AEA amidohydrolase), a serine amidase present in cell membranes. Following a strategy that has been used to develop inhibitors that covalently bind to the active site of serine peptidases, diazomethyl arachidonyl ketone (DAK) was synthesized and its effects on AEA amidohydrolase were determined. DAK inhibits the hydrolysis of AEA by rat brain membranes with an IC50 value of 0.5 microM. At low concentrations, DAK reduces the Vmax and increases the K(m) of the enzyme for its substrate AEA, which suggests that it is both a competitive and noncompetitive inhibitor. At higher concentrations, DAK inhibition is completely noncompetitive. DAK inhibition of membrane-associated AEA amidohydrolase is irreversible because hydrolytic activity is not restored with extensive washing or dialysis of the membranes. Furthermore, DAK inhibition is not reversible by anion exchange chromatography of the subsequently solubilized enzyme. In contrast, DAK inhibition of detergent-solubilized enzyme exhibits competitive kinetics and is reversible upon ion exchange chromatography. Exposure of C6 glioma cells to DAK results in concentration-related inhibition of AEA amidohydrolase activity in cellular membranes with an IC50 value of 0.3 microM. In summary, these studies demonstrate that DAK is an irreversible inhibitor of AEA amidohydrolase in its native membrane and provides a useful tool with which to study the role of AEA amidohydrolase in the termination of action of AEA.

  15. Features of alpha-synuclein that could explain the progression and irreversibility of Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Scarlet eGallegos

    2015-03-01

    Full Text Available Alpha-synuclein is a presynaptic protein expressed throughout the central nervous system, and it is the main component of Lewy bodies, one of the histopathological features of Parkinson’s disease (PD which is a progressive and irreversible neurodegenerative disorder. The conformational flexibility of α-synuclein allows it to adopt different conformations, i.e. bound to membranes or form aggregates, the oligomers are believed to be the more toxic species. In this review, we will focus on two major features of α-synuclein, transmission and toxicity that could help to understand the pathological characteristics of PD. One important feature of α-synuclein is its ability to be transmitted from neuron to neuron using mechanisms such as endocytosis, plasma membrane penetration or through exosomes, thus propagating the Lewy body pathology to different brain regions thereby contributing to the progressiveness of PD. The second feature of α-synuclein is that it confers cytotoxicity to recipient cells, principally when it is in an oligomeric state. This form causes mitochondrial dysfunction, endoplasmic reticulum stress, oxidative stress, proteasome impairment, disruption of plasma membrane and pore formation, and lead to apoptosis pathway activation and consequent cell death. The complexity of α-synuclein oligomerization and formation of toxic species could be a major factor for the irreversibility of PD and could also explain the lack of successful therapies to halt the disease.

  16. Selective Targeting of Extracellular Insulin-Degrading Enzyme by Quasi-Irreversible Thiol-Modifying Inhibitors.

    Science.gov (United States)

    Abdul-Hay, Samer O; Bannister, Thomas D; Wang, Hui; Cameron, Michael D; Caulfield, Thomas R; Masson, Amandine; Bertrand, Juliette; Howard, Erin A; McGuire, Michael P; Crisafulli, Umberto; Rosenberry, Terrone R; Topper, Caitlyn L; Thompson, Caroline R; Schürer, Stephan C; Madoux, Franck; Hodder, Peter; Leissring, Malcolm A

    2015-12-18

    Many therapeutically important enzymes are present in multiple cellular compartments, where they can carry out markedly different functions; thus, there is a need for pharmacological strategies to selectively manipulate distinct pools of target enzymes. Insulin-degrading enzyme (IDE) is a thiol-sensitive zinc-metallopeptidase that hydrolyzes diverse peptide substrates in both the cytosol and the extracellular space, but current genetic and pharmacological approaches are incapable of selectively inhibiting the protease in specific subcellular compartments. Here, we describe the discovery, characterization, and kinetics-based optimization of potent benzoisothiazolone-based inhibitors that, by virtue of a unique quasi-irreversible mode of inhibition, exclusively inhibit extracellular IDE. The mechanism of inhibition involves nucleophilic attack by a specific active-site thiol of the enzyme on the inhibitors, which bear an isothiazolone ring that undergoes irreversible ring opening with the formation of a disulfide bond. Notably, binding of the inhibitors is reversible under reducing conditions, thus restricting inhibition to IDE present in the extracellular space. The identified inhibitors are highly potent (IC50(app) = 63 nM), nontoxic at concentrations up to 100 μM, and appear to preferentially target a specific cysteine residue within IDE. These novel inhibitors represent powerful new tools for clarifying the physiological and pathophysiological roles of this poorly understood protease, and their unusual mechanism of action should be applicable to other therapeutic targets.

  17. Catalytic irreversible inhibition of bacterial and plant arginine decarboxylase activities by novel substrate and product analogues.

    Science.gov (United States)

    Bitonti, A J; Casara, P J; McCann, P P; Bey, P

    1987-02-15

    Arginine decarboxylase (ADC) activity from Escherichia coli and two plant species (oats and barley) was inhibited by five new substrate (arginine) and product (agmatine) analogues. The five compounds, (E)-alpha-monofluoromethyldehydroarginine (delta-MFMA), alpha-monofluoromethylarginine (MFMA), alpha-monofluoromethylagatine (FMA), alpha-ethynylagmatine (EA) and alpha-allenylagmatine (AA), were all more potent inhibitors of ADC activity than was alpha-difluoromethylarginine (DFMA), the only irreversible inhibitor of this enzyme described previously. The inhibition caused by the five compounds was apparently enzyme-activated and irreversible, since the loss of enzyme activity followed pseudo-first-order kinetics, was time-dependent, the natural substrate of ADC (arginine) blocked the effects of the inhibitors, and the inhibition remained after chromatography of inhibited ADC on Sephadex G-25 or on overnight dialysis of the enzyme. DFMA, FMA, delta-MFMA and MFMA were effective at very low concentrations (10 nM-10 microM) at inhibiting ADC activity in growing E. coli. FMA was also shown to deplete putrescine effectively in E. coli, particularly when combined with an inhibitor of ornithine decarboxylase, alpha-monofluoromethyl-putrescine. The potential uses of the compounds for the study of the role of polyamine biosynthesis in bacteria and plants is discussed.

  18. Time-resolved single-shot terahertz time-domain spectroscopy for ultrafast irreversible processes

    Science.gov (United States)

    Zhai, Zhao-Hui; Zhong, Sen-Cheng; Li, Jun; Zhu, Li-Guo; Meng, Kun; Li, Jiang; Liu, Qiao; Peng, Qi-Xian; Li, Ze-Ren; Zhao, Jian-Heng

    2016-09-01

    Pulsed terahertz spectroscopy is suitable for spectroscopic diagnostics of ultrafast events. However, the study of irreversible or single shot ultrafast events requires ability to record transient properties at multiple time delays, i.e., time resolved at single shot level, which is not available currently. Here by angular multiplexing use of femtosecond laser pulses, we developed and demonstrated a time resolved, transient terahertz time domain spectroscopy technique, where burst mode THz pulses were generated and then detected in a single shot measurement manner. The burst mode THz pulses contain 2 sub-THz pulses, and the time gap between them is adjustable up to 1 ns with picosecond accuracy, thus it can be used to probe the single shot event at two different time delays. The system can detect the sub-THz pulses at 0.1 THz-2.5 THz range with signal to noise ratio (SNR) of ˜400 and spectrum resolution of 0.05 THz. System design was described here, and optimizations of single shot measurement of THz pulses were discussed in detail. Methods to improve SNR were also discussed in detail. A system application was demonstrated where pulsed THz signals at different time delays of the ultrafast process were successfully acquired within single shot measurement. This time resolved transient terahertz time domain spectroscopy technique provides a new diagnostic tool for irreversible or single shot ultrafast events where dynamic information can be extracted at terahertz range within one-shot experiment.

  19. Exergoeconomic optimization of an irreversible regenerated air refrigerator with constant-temperature heat reservoirs

    Directory of Open Access Journals (Sweden)

    Yi Zhang, Lingeng Chen, Guozhong Chai

    2015-01-01

    Full Text Available Based on the finite time exergoeconomic method, the performance analysis and optimization of an irreversible regenerated air refrigerator cycle are carried out by taking the profit rate as the optimization objective. The profit rate is defined as the difference between the revenue rate of output exergy and the cost rate of input exergy. The analytical expression for profit rate is derived, taking into account several irreversibilities, such as heat resistance, losses due to the pressure drop and the effects of non-isentropic expansion as well as compression. The influences of several parameters such as the temperature ratio of reservoirs, the efficiencies of both compressor and expander, the pressure recovery coefficient and so on are discussed by numerical examples. According to the simulation results, the double-maximum profit rate can be achieved when the pressure ratio and the distributions of heat conductance reach their optimal values respectively. By varying the price ratio, the relationship between the profit rate objective and other objectives can be established and the implementation of profit rate as objective can achieve higher COP compared to the cases using ecological function and cooling load as objectives.

  20. Morbidade na criança e lesões irreversíveis ocasionadas por material de limpeza Children morbidity and irreversible injury caused by cleaning material

    Directory of Open Access Journals (Sweden)

    Sarah Anna Macieira

    2001-06-01

    Full Text Available O presente trabalho tem como objetivo relatar um estudo de caso desenvolvido com uma criança desnutrida, de 6 anos, do sexo feminino, com estenose de esôfago. Como estratégia metodológica realizamos a coleta de dados através de estudo em prontuário médico e visita domiciliar. Observamos a falta de percepção da família sobre os riscos dos produtos de limpeza ao alcance da criança; a necessidade de acompanhamento da equipe de saúde (enfermeiro, psicólogo, médico, assistente social e nutricionista, cobrando da mãe cuidados específicos de nutrição, cuidados com a gastrostomia, medicação, prevenção de acidentes domésticos, e orientando-a como guardar material de limpeza.The purpose of the present work is to report a case study on a malnourished 6 year old suffering from esophagus stenosis. As a methodological strategy data collection was performed through studies of medical charts and house visits. It was observed a lack of perception by the family regarding the dangers of having cleaning products within the reach of the child. The necessity of attendance of the health team (nurse, psychologist, doctor, social worker and nutritionist, guiding the mother with respect to special care with nutrition, care with the gastrotomy, medication, and domestic accident prevention, with advice on how to keep cleaning material.

  1. Maculopatia tóxica por cloroquina Chloroquine toxic maculopathy

    Directory of Open Access Journals (Sweden)

    Nikias Alves da Silva

    2009-06-01

    Full Text Available O fosfato de cloroquina é uma droga largamente utilizada no tratamento de doenças crônicas de autoagressão, mais comumente no controle da artrite reumatóide, do lupus eritematoso discóide ou disseminado, da porfiria cutânea, da urticária solar e outras afecções dermatológicas. Embora a incidência de toxicidade retiniana por esta droga seja baixa, mesmo com o emprego da dose máxima recomendada, sua ocorrência tem grande relevância por acometer a região macular com importante e irreversível comprometimento visual. Trata-se no presente caso de uma paciente de 44 anos, portadora de artrite reumatóide há 19 anos, que fez uso de fosfato de cloroquina na dose de 250 mg/dia durante dois períodos de 4 e 3 anos, intercalados por um período de 8 anos em que usou methotrexate. Ao final do segundo período de uso da cloroquina, foi observada a maculopatia, a partir de quando a droga foi definitivamente substituída por methotrexate e prednisona. Por seu caráter típico e conspícuo, a maculopatia em questão se presta muito bem para ilustrar os achados dos principais métodos propedêuticos que devem ser empregados para caracterizá-la, inclusive a tomografia de coerência óptica.Chloroquine phosphate is widely used for the treatment of chronic autoimune diseases, most commonly rheumatoid arthritis, discoid or disseminated lupus erythematous, light sensitivity eruptions as well as other dermatologic affections. Although the incidence of retinal toxicity by this drug is low even with the maximally recomended dose, its occurrence is relevant because it damages the macula with an important and irreversible visual impairment. A 44-year-old white female patient who had suffered from rheumatoid arthritis for about 19 years had been under treatment with chloroquine phosphate in the daily dose of 250 mg during two periods of 4 and 3 years, intercalated by an 8-year period of methotrexate usage. At the end of the 3-year period, a maculopathy

  2. Se los por se lo

    OpenAIRE

    José Luis Rivarola

    1985-01-01

    El sistema de la conjugación "objetiva" plantea interesantesproblemas que fueron tratados en parte por K. Heger (1966) en suestudio comparativo del francés y del español. De la comparaciónse desprende, por ejemplo, que en español hay un cierto número deambigüedades que no permiten establecer un "paradigma tan completo y unívoco" como en el caso del francés. Dentro de estas ambigüedades se encuentran las que propicia el gramema se: "El morfema [gramema] se funciona no sólo como pronombre refle...

  3. Ptose palpebral causada por Paquidermoperiostose

    Directory of Open Access Journals (Sweden)

    Patricia Regina de Pinho Tavares

    2014-08-01

    Full Text Available A paquidermoperiostose é uma síndrome caracterizada por acometimento cutâneo e ósseo, e em alguns casos ocorre comprometimento palpebral leve. É uma síndrome rara, idiopática ou hereditária, com provável herança autossômica dominante de penetrância variável. Descreve-se o caso de um paciente com ptose grave por paquidermoperiostose elucidando sua fisiopatologia e conduta cirúrgica aplicada.

  4. Model of the Evolution of Deformation Defects and Irreversible Strain at Thermal Cycling of Stressed TiNi Alloy Specimen

    Directory of Open Access Journals (Sweden)

    Volkov Aleksandr E.

    2015-01-01

    Full Text Available This microstructural model deals with simulation both of the reversible and irreversible deformation of a shape memory alloy (SMA. The martensitic transformation and the irreversible deformation due to the plastic accommodation of martensite are considered on the microscopic level. The irreversible deformation is described from the standpoint of the plastic flow theory. Isotropic hardening and kinematic hardening are taken into account and are related to the densities of scattered and oriented deformation defects. It is supposed that the phase transformation and the micro plastic deformation are caused by the generalized thermodynamic forces, which are the derivatives of the Gibbs’ potential of the two-phase body. In terms of these forces conditions for the phase transformation and for the micro plastic deformation on the micro level are formulated. The macro deformation of the representative volume of the polycrystal is calculated by averaging of the micro strains related to the evolution of the martensite Bain’s variants in each grain comprising this volume. The proposed model allowed simulating the evolution of the reversible and of the irreversible strains of a stressed SMA specimen under thermal cycles. The results show a good qualitative agreement with available experimental data. Specifically, it is shown that the model can describe a rather big irreversible strain in the first thermocycle and its fast decrease with the number of cycles.

  5. Irreversibility analysis for optimization design of plate fin heat exchangers using a multi-objective cuckoo search algorithm

    International Nuclear Information System (INIS)

    Highlights: • The first application of IMOCS for plate-fin heat exchanger design. • Irreversibility degrees of heat transfer and fluid friction are minimized. • Trade-off of efficiency, total cost and pumping power is achieved. • Both EGM and EDM methods have been compared in the optimization of PFHE. • This study has superiority over other single-objective optimization design. - Abstract: This paper introduces and applies an improved multi-objective cuckoo search (IMOCS) algorithm, a novel met-heuristic optimization algorithm based on cuckoo breeding behavior, for the multi-objective optimization design of plate-fin heat exchangers (PFHEs). A modified irreversibility degree of the PFHE is separated into heat transfer and fluid friction irreversibility degrees which are adopted as two initial objective functions to be minimized simultaneously for narrowing the search scope of the design. The maximization efficiency, minimization of pumping power, and total annual cost are considered final objective functions. Results obtained from a two dimensional normalized Pareto-optimal frontier clearly demonstrate the trade-off between heat transfer and fluid friction irreversibility. Moreover, a three dimensional Pareto-optimal frontier reveals a relationship between efficiency, total annual cost, and pumping power in the PFHE design. Three examples presented here further demonstrate that the presented method is able to obtain optimum solutions with higher accuracy, lower irreversibility, and fewer iterations as compared to the previous methods and single-objective design approaches

  6. Celulitis por citomegalovirus Cytomegalovirus cellulitis

    Directory of Open Access Journals (Sweden)

    A. Ruiz Lascano

    2002-12-01

    Full Text Available Las lesiones cutáneas por citomegalovirus (CMV son infrecuentes y a menudo una manifestación tardía de una enfermedad sistémica, que generalmente anuncia un curso fatal. Comunicamos un caso de celulitis por CMV: una mujer de 70 años con trasplante renal efectuado 1 mes antes de la consulta, terapia inmunosupresora con ciclosporina A y metilprednisona. La paciente ingresó por fiebre, dolor e impotencia funcional en pierna derecha. Comprobamos la existencia de una placa de 8 por 4 cm eritematoedematosa. La tratamos con antibióticos sin mejoría, por lo que realizamos un estudio histopatológico de piel que mostró cambios citopáticos compatibles con infección por CMV. Los cultivos bacteriológicos y micológicos fueron negativos. La inmunohistoquímica específica para CMV y el estudio de reacción en cadena de la polimerasa (PCR de la biopsia de piel fueron positivas, al igual que la antigenemia. El tratamiento con ganciclovir produjo la mejoría del cuadro clínico. En la literatura revisada no hemos encontrado la celulitis como manifestación de enfermedad cutánea por CMV.Cutaneous lesions in CMV infection are rare, often a late manifestation of systemic infection, and usually herald a fatal course. A 70 year-old woman received a kidney transplantation one month before consulting and immunosuppressive therapy that included cyclosporine A and methylprednisone. She complained of fever, local pain in her right leg, and an erythematous and swelling plaque. She was treated with intravenous antibiotics without improvement. A skin biopsy was performed and the tissue obtained was sent for bacterial and fungal cultures as well as for histological examination. Cultures were negative. The biopsy showed CMV cytopathic changes. Immunoperoxidase staining was positive for CMV and polymerase chain reaction (PCR testing revealed CMV DNA. She was treated with ganciclovir with resolution of the lesion. CMV cellulitis is a rare cutaneous manifestation

  7. Selective and irreversible inhibitors of mosquito acetylcholinesterases for controlling malaria and other mosquito-borne diseases.

    Science.gov (United States)

    Pang, Yuan-Ping; Ekström, Fredrik; Polsinelli, Gregory A; Gao, Yang; Rana, Sandeep; Hua, Duy H; Andersson, Björn; Andersson, Per Ola; Peng, Lei; Singh, Sanjay K; Mishra, Rajesh K; Zhu, Kun Yan; Fallon, Ann M; Ragsdale, David W; Brimijoin, Stephen

    2009-01-01

    New insecticides are urgently needed because resistance to current insecticides allows resurgence of disease-transmitting mosquitoes while concerns for human toxicity from current compounds are growing. We previously reported the finding of a free cysteine (Cys) residue at the entrance of the active site of acetylcholinesterase (AChE) in some insects but not in mammals, birds, and fish. These insects have two AChE genes (AP and AO), and only AP-AChE carries the Cys residue. Most of these insects are disease vectors such as the African malaria mosquito (Anopheles gambiae sensu stricto) or crop pests such as aphids. Recently we reported a Cys-targeting small molecule that irreversibly inhibited all AChE activity extracted from aphids while an identical exposure caused no effect on the human AChE. Full inhibition of AChE in aphids indicates that AP-AChE contributes most of the enzymatic activity and suggests that the Cys residue might serve as a target for developing better aphicides. It is therefore worth investigating whether the Cys-targeting strategy is applicable to mosquitocides. Herein, we report that, under conditions that spare the human AChE, a methanethiosulfonate-containing molecule at 6 microM irreversibly inhibited 95% of the AChE activity extracted from An. gambiae s. str. and >80% of the activity from the yellow fever mosquito (Aedes aegypti L.) or the northern house mosquito (Culex pipiens L.) that is a vector of St. Louis encephalitis. This type of inhibition is fast ( approximately 30 min) and due to conjugation of the inhibitor to the active-site Cys of mosquito AP-AChE, according to our observed reactivation of the methanethiosulfonate-inhibited AChE by 2-mercaptoethanol. We also note that our sulfhydryl agents partially and irreversibly inhibited the human AChE after prolonged exposure (>4 hr). This slow inhibition is due to partial enzyme denaturation by the inhibitor and/or micelles of the inhibitor, according to our studies using atomic force

  8. MRI study on reversible and irreversible electroporation induced blood brain barrier disruption.

    Directory of Open Access Journals (Sweden)

    Mohammad Hjouj

    Full Text Available Electroporation, is known to induce cell membrane permeabilization in the reversible (RE mode and cell death in the irreversible (IRE mode. Using an experimental system designed to produce a continuum of IRE followed by RE around a single electrode we used MRI to study the effects of electroporation on the brain. Fifty-four rats were injected with Gd-DOTA and treated with a G25 electrode implanted 5.5 mm deep into the striata. MRI was acquired immediately after treatment, 10 min, 20 min, 30 min, and up to three weeks following the treatment using: T1W, T2W, Gradient echo (GE, serial SPGR (DCE-MRI with flip angles ranging over 5-25°, and diffusion-weighted MRI (DWMRI. Blood brain barrier (BBB disruption was depicted as clear enhancement on T1W images. The average signal intensity in the regions of T1-enhancement, representing BBB disruption, increased from 1887±83 (arbitrary units immediately post treatment to 2246±94 20 min post treatment, then reached a plateau towards the 30 min scan where it reached 2289±87. DWMRI at 30 min showed no significant effects. Early treatment effects and late irreversible damage were clearly depicted on T2W. The enhancing volume on T2W has increased by an average of 2.27±0.27 in the first 24-48 hours post treatment, suggesting an inflammatory tissue response. The permanent tissue damage, depicted as an enhancing region on T2W, 3 weeks post treatment, decreased to an average of 50±10% of the T2W enhancing volumes on the day of the treatment which was 33±5% of the BBB disruption volume. Permanent tissue damage was significantly smaller than the volume of BBB disruption, suggesting, that BBB disruption is associated with RE while tissue damage with IRE. These results demonstrate the feasibility of applying reversible and irreversible electroporation for transient BBB disruption or permanent damage, respectively, and applying MRI for planning/monitoring disruption volume/shape by optimizing electrode positions

  9. A statistical model for multidimensional irreversible electroporation cell death in tissue

    Directory of Open Access Journals (Sweden)

    Rubinsky Boris

    2010-02-01

    Full Text Available Abstract Background Irreversible electroporation (IRE is a minimally invasive tissue ablation technique which utilizes electric pulses delivered by electrodes to a targeted area of tissue to produce high amplitude electric fields, thus inducing irreversible damage to the cell membrane lipid bilayer. An important application of this technique is for cancer tissue ablation. Mathematical modelling is considered important in IRE treatment planning. In the past, IRE mathematical modelling used a deterministic single value for the amplitude of the electric field required for causing cell death. However, tissue, particularly cancerous tissue, is comprised of a population of different cells of different sizes and orientations, which in conventional IRE are exposed to complex electric fields; therefore, using a deterministic single value is overly simplistic. Methods We introduce and describe a new methodology for evaluating IRE induced cell death in tissue. Our approach employs a statistical Peleg-Fermi model to correlate probability of cell death in heterogeneous tissue to the parameters of electroporation pulses such as the number of pulses, electric field amplitude and pulse length. For treatment planning, the Peleg-Fermi model is combined with a numerical solution of the multidimensional electric field equation cast in a dimensionless form. This is the first time in which this concept is used for evaluating IRE cell death in multidimensional situations. Results We illustrate the methodology using data reported in literature for prostate cancer cell death by IRE. We show how to fit this data to a Fermi function in order to calculate the critical statistic parameters. To illustrate the use of the methodology, we simulated 2-D irreversible electroporation protocols and produced 2-D maps of the statistical distribution of cell death in the treated region. These plots were compared to plots produced using a deterministic model of cell death by IRE and

  10. (phoenicopterus roseus por intoxicación aguda por plomo

    Directory of Open Access Journals (Sweden)

    D Romero

    2007-01-01

    Full Text Available La presencia de plomo en el medio ambiente es un hecho indiscutible. Ello es objeto de gran interés sanitario pues repercute tanto en la salud de los animales como en la del ser humano. El plumbismo es una intoxicación que puede afectar a cualquier especie animal. En el ámbito de la fauna silvestre se asocia principalmente a la actividad cinegética en los humedales y a la ingestión de plomo metálico por parte de las aves que frecuentan estos ecosistemas. En España cada año mueren decenas de miles de aves acuáticas como consecuencia de la ingesta de perdigones de plomo. En los individuos capturados enfermos se pueden observar signos clínicos, mientras que a partir de muestras de cadáveres se obtienen datos sobre niveles tisulares de plomo. Sin embargo la evaluación de lesiones anatomopatológicas en animales de vida silvestre es difícil de realizar por la dificultad de encontrar animales recién muertos o afectados de un cuadro agudo mortal. La reproducción de esta patología en animales de experimentación se suele realizar en cisnes, palomas o patos, pero no en flamencos, por lo que no es usual disponer de datos histológicos en esta especie. En este trabajo presentamos la clínica, analítica y estudio microscópico de diferentes tejidos de un flamenco común (Phoenicopterus roseus muerto por plumbismo.

  11. Influence of Irreversible Adsorption on the Glass Transition Temperature of Polymer Thin Films as Measured by Fluorescence

    Science.gov (United States)

    Burroughs, Mary; Priestley, Rodney

    2014-03-01

    Polymers confined to the nanometer length scale have been shown to exhibit deviations in the glass transition temperature (Tg) from the bulk. With the increasing use of confined polymers in nanotechnology, understanding and predicting this behavior is extremely relevant to industries ranging from pharmaceuticals to organic electronics. Recent work (Napolitano, Wübbenhorst, Nature Communications, 2, 260 (2011)) has connected deviations in Tg under confinement with irreversible physical adsorption of polymer chains at substrate interfaces. Here we investigate the influence of irreversibly adsorbed layers on the Tg of polystyrene (PS) thin films supported on silica via fluorescence. We examine the Tg of the brushes as a function of annealing time and irreversibly adsorbed layer thickness. By incorporating fluorescently labeled polymer layers into multilayered films of unlabeled polymer, we will examine the influence of brushes on adjacent layers dynamics. Finally, we will compare the results on PS with those of poly(methyl methacrylate).

  12. Finite-time exergoeconomic performance of a generalized irreversible Carnot heat engine with complex heat transfer law

    Directory of Open Access Journals (Sweden)

    Jun Li, Lingen Chen, Yanlin Ge, Fengrui Sun

    2015-01-01

    Full Text Available The finite time exergoeconomic performance of the generalized irreversible Carnot heat engine with the losses of heat resistance, heat leakage and internal irreversibility, and with a complex heat transfer law, including generalized convective heat transfer law and generalized radiative heat transfer law is investigated in this paper. The focus of this paper is to obtain the compromised optimization between economics (profit and the energy utilization factor (efficiency for the generalized irreversible Carnot heat engine, by searching the optimum efficiency at maximum profit, which is termed as the finite time exergoeconomic performance bound. The obtained results include those obtained in many literatures and can provide some theoretical guidelines for the design of practical heat engines.

  13. Rapid Determination of the Specificity Constant of Irreversible Inhibitors (kinact/KI) by Means of an Endpoint Competition Assay.

    Science.gov (United States)

    Miyahisa, Ikuo; Sameshima, Tomoya; Hixon, Mark S

    2015-11-16

    Owing to their covalent target occupancy, irreversible inhibitors require low exposures and offer long duration, and their use thus represents a powerful strategy for achieving pharmacological efficacy. Importantly, the potency metric of irreversible inhibitors is kinact/KI not IC50. A simple approach to measuring kinact/KI was developed that makes use of an irreversible probe for competitive assays run to completion against test compounds. In this system, the kinact/KI value of the test compound is equal to (kinact/KI)probe ×[probe]/IC50. The advantages of this method include simplicity, high throughput, and application to all target classes, and it only requires an in-depth kinetic evaluation of the probe.

  14. Is ‘hit and run’ a single word? The processing of irreversible binomials in neglect dyslexia

    Directory of Open Access Journals (Sweden)

    Giorgio eArcara

    2012-02-01

    Full Text Available The present study is the first neuropsychological investigation into the problem of the mental representation and processing of irreversible binomials, i.e. word pairs linked by a conjunction (e.g. ‘hit and run’, ‘dead or alive’. In order to test their lexical status, the phenomenon of neglect dyslexia is explored.People with left-sided neglect dyslexia show a clear lexical effect: they can read irreversible binomials better (i.e., by dropping the leftmost words less frequently when their components are presented in their correct order. This may be taken as an indication that they treat these constructions as lexical, not decomposable, elements. This finding therefore constitutes strong evidence that irreversible binomials tend to be stored in the mental lexicon as a whole and that this whole form is preferably addressed in the retrieval process.

  15. Local Ablative Strategies for Ductal Pancreatic Cancer (Radiofrequency Ablation, Irreversible Electroporation): A Review.

    Science.gov (United States)

    Paiella, Salvatore; Salvia, Roberto; Ramera, Marco; Girelli, Roberto; Frigerio, Isabella; Giardino, Alessandro; Allegrini, Valentina; Bassi, Claudio

    2016-01-01

    Pancreatic ductal adenocarcinoma (PDAC) has still a dismal prognosis. Locally advanced pancreatic cancer (LAPC) accounts for the 40% of the new diagnoses. Current treatment options are based on chemo- and radiotherapy regimens. Local ablative techniques seem to be the future therapeutic option for stage-III patients with PDAC. Radiofrequency Ablation (RFA) and Irreversible Electroporation (IRE) are actually the most emerging local ablative techniques used on LAPC. Initial clinical studies on the use of these techniques have already demonstrated encouraging results in terms of safety and feasibility. Unfortunately, few studies on their efficacy are currently available. Even though some reports on the overall survival are encouraging, randomized studies are still required to corroborate these findings. This study provides an up-to-date overview and a thematic summary of the current available evidence on the application of RFA and IRE on PDAC, together with a comparison of the two procedures. PMID:26981115

  16. The Effect of Blood Flow on Magnetic Resonance Imaging of Non Thermal Irreversible Electroporation

    Science.gov (United States)

    Hjouj, Mohammad; Lavee, Jacob; Last, David; Guez, David; Daniels, Dianne; Sharabi, Shirley; Rubinsky, Boris; Mardor, Yael

    2013-10-01

    To generate an understanding of the physiological significance of MR images of Non-Thermal Irreversible Electroporation (NTIRE) we compared the following MR imaging sequences: T1W, T2W, PD, GE, and T2 SPAIR acquired after NTIRE treatment in a rodent liver model. The parameters that were studied included the presence or absence of a Gd-based contrast agent, and in vivo and ex-vivo NTIRE treatments in the same liver. NTIRE is a new minimally invasive tissue ablation modality in which pulsed electric fields cause molecularly selective cell death while, the extracellular matrix and large blood vessels remain patent. This attribute of NTIRE is of major clinical importance as it allows treatment of undesirable tissues near critical blood vessels. The presented study results suggest that MR images acquired following NTIRE treatment are all directly related to the unique pattern of blood flow after NTIRE treatment and are not produced in the absence of blood flow.

  17. Local Ablative Strategies for Ductal Pancreatic Cancer (Radiofrequency Ablation, Irreversible Electroporation: A Review

    Directory of Open Access Journals (Sweden)

    Salvatore Paiella

    2016-01-01

    Full Text Available Pancreatic ductal adenocarcinoma (PDAC has still a dismal prognosis. Locally advanced pancreatic cancer (LAPC accounts for the 40% of the new diagnoses. Current treatment options are based on chemo- and radiotherapy regimens. Local ablative techniques seem to be the future therapeutic option for stage-III patients with PDAC. Radiofrequency Ablation (RFA and Irreversible Electroporation (IRE are actually the most emerging local ablative techniques used on LAPC. Initial clinical studies on the use of these techniques have already demonstrated encouraging results in terms of safety and feasibility. Unfortunately, few studies on their efficacy are currently available. Even though some reports on the overall survival are encouraging, randomized studies are still required to corroborate these findings. This study provides an up-to-date overview and a thematic summary of the current available evidence on the application of RFA and IRE on PDAC, together with a comparison of the two procedures.

  18. Effects of oxymorphazone in frogs: long lasting antinociception in vivo, and apparently irreversible binding in vitro

    International Nuclear Information System (INIS)

    Oxymorphazone was found to be a relatively weak antinociceptive drug in intact frog (Rana esculenta) when acetic acid was used as pain stimulus. Frogs remained analgesic for at least 48 hrs following oxymorphazone administration. The ligand increased the latency of wiping reflex in spinal frogs too. There effects were blocked by naloxone. In equilibrium binding studies (3H)oxymorphazone had high affinity to the opioid receptors of frog brain and spinal cord as well. Kinetic experiments show that only 25% of the bound (3H)oxymorphazone is readily dissociable. Preincubation of the membranes with labeled oxymorphazone results in a washing resistant inhibition of the opioid binding sites. At least 70% of the (3H)oxymorphazone specific binding is apparently irreversible after reaction at 5 nM ligand concentration, and this can be enhanced by a higher concentration of tritiated ligand

  19. Universal Ideal Behavior and Macroscopic Work Relation of Linear Irreversible Stochastic Thermodynamics

    CERN Document Server

    Ma, Yi-An

    2015-01-01

    We revisit the Ornstein-Uhlenbeck (OU) process as the fundamental mathematical description of linear irreversible phenomena, with fluctuations, near an equilibrium. By identifying the underlying circulating dynamics in a stationary process as the natural generalization of classical conservative mechanics, a bridge between a family of OU processes with equilibrium fluctuations and thermodynamics is established through the celebrated Helmholtz theorem. The Helmholtz theorem provides an emergent macroscopic "equation of state" of the entire system, which exhibits a universal ideal thermodynamic behavior. Fluctuating macroscopic quantities are studied from the stochastic thermodynamic point of view and a non-equilibrium work relation is obtained in the macroscopic picture, which may facilitate experimental study and application of the equalities due to Jarzynski, Crooks, and Hatano and Sasa.

  20. Effect of irreversible electroporation on three-dimensional cell culture model.

    Science.gov (United States)

    Kurata, Kosaku; Matsushita, Masahiro; Yoshii, Takashi; Fukunaga, Takanobu; Takamatsu, Hiroshi

    2012-01-01

    Irreversible electroporation (IRE) is a new treatment to necrotize abnormal cells by high electric pulses. Electric potential difference over 1 V across the plasma membrane permanently permeabilizes the cell with keeping the extracellular matrix intact if the thermal damage due to the Joule heating effect is avoided. This is the largest advantage of the IRE compared to the other conventional treatment. However, since the IRE has just started to be used in clinical tests, it is important to predict the necrotized region that depends on pulse parameters and electrode arrangement. We therefore examined the numerical solution to the Laplace equation for the static electric field to predict the IRE-induced cell necrosis. Three-dimensionally (3-D) cultured cells in a tissue phantom were experimentally subjected to the electric pulses through a pair of puncture electrodes. The necrotized area was determined as a function of the pulse repetition and compared with the area that was estimated by the numerical analysis. PMID:23365861

  1. Kinetics of irreversible inhibition of yeast alcohol dehydrogenase during modification by o-phthaldehyde.

    Science.gov (United States)

    Le, W P; Yan, S X; Huang, M Q; Zhang, Y X; Zhou, H M

    The kinetic theory of the substrate reaction during irreversible inhibition of enzyme activity described previously has been applied to a study on the kinetics of the course of inactivation of yeast alcohol dehydrogenase (YADH) by o-phthaldehyde (OPTA). The microscopic constants for the reaction of the inactivators with the free enzyme and with the enzyme-substrate complexes were determined. The inactivation is a monophasic pseudo-first-order reaction with OPTA. The apparent rate constant A is independent of the OPTA concentration, indicating that the inactivation is a noncomplexing inhibition. The marked protective effect of substrates on the inactivation of YADH by OPTA has been observed. This result suggests that the modification of the enzyme by OPTA may occur at the active site.

  2. Mass and Heat Diffusion in Ternary Polymer Solutions: A Classical Irreversible Thermodynamics Approach

    CERN Document Server

    Es-haghi, S Shams

    2016-01-01

    Governing equations for evolution of concentration and temperature in three-component systems were derived in the framework of classical irreversible thermodynamics using Onsager variational principle and were presented for solvent/solvent/polymer and solvent/polymer/polymer systems. The derivation was developed from the Gibbs equation of equilibrium thermodynamics using the local equilibrium hypothesis, Onsager reciprocal relations and Prigogine theorem for systems in mechanical equilibrium. It was shown that the details of mass and heat diffusion phenomena in a ternary system are completely expressed by a 3x3 matrix whose entries are mass diffusion coefficients (4 entries), thermal diffusion coefficients (2 entries) and three entries that describe the evolution of heat in the system. The entries of the diffusion matrix are related to the elements of Onsager matrix that are bounded by some constraints to satisfy the positive definiteness of entropy production in the system. All the elements of diffusion matr...

  3. Development of Linear Irreversible Thermodynamic Model for Oxidation Reduction Potential in Environmental Microbial System

    Science.gov (United States)

    Cheng, Hong-Bang; Kumar, Mathava; Lin, Jih-Gaw

    2007-01-01

    Nernst equation has been directly used to formulate the oxidation reduction potential (ORP) of reversible thermodynamic conditions but applied to irreversible conditions after several assumptions and/or modifications. However, the assumptions are sometimes inappropriate in the quantification of ORP in nonequilibrium system. We propose a linear nonequilibrium thermodynamic model, called microbial related reduction and oxidation reaction (MIRROR Model No. 1) for the interpretation of ORP in biological process. The ORP was related to the affinities of catabolism and anabolism. The energy expenditure of catabolism and anabolism was directly proportional to overpotential (η), straight coefficient of electrode (LEE), and degree of coupling between catabolism and ORP electrode, respectively. Finally, the limitations of MIRROR Model No. 1 were discussed for expanding the applicability of the model. PMID:17496027

  4. Study on the Irreversible Thermodynamics of a Marine Engine Exhaust-powered Adsorption Refrigerating System

    Institute of Scientific and Technical Information of China (English)

    XIE Yingchun; MEI Ning; XU Zhen

    2006-01-01

    This study investigates the heat and mass transfer mechanism of a marine engine exhaust-powered adsorption refrigerating system by using irreversible thermodynamics. The equations of entropy-production rate and the linear phenomenological equations of thermodynamic flux and force are established. The conventional experimental facilities of unit tube are developed and the phenomenological coefficients are obtained by fitting the experimental data. It is concluded that the thermodynamic process in the adsorbent bed is determined by the coupling effect of the heat and mass transfer; furthermore, the mass transfer is determined by the heat transfer. Taking some measures to increase heat transfer can improve the performance of the adsorption refrigerating system. The conclusions presented in this paper may be of value to the engineering applications of the system.

  5. Chemical modeling of irreversible reactions in nuclear waste-water-rock systems

    International Nuclear Information System (INIS)

    Chemical models of aqueous geochemical systems are usually built on the concept of thermodynamic equilibrium. Though many elementary reactions in a geochemical system may be close to equilibrium, others may not be. Chemical models of aqueous fluids should take into account that many aqueous redox reactions are among the latter. The behavior of redox reactions may critically affect migration of certain radionuclides, especially the actinides. In addition, the progress of reaction in geochemical systems requires thermodynamic driving forces associated with elementary reactions not at equilibrium, which are termed irreversible reactions. Both static chemical models of fluids and dynamic models of reacting systems have been applied to a wide spectrum of problems in water-rock interactions. Potential applications in nuclear waste disposal range from problems in geochemical aspects of site evaluation to those of waste-water-rock interactions. However, much further work in the laboratory and the field will be required to develop and verify such applications of chemical modeling

  6. A non-linear irreversible thermodynamic perspective on organic pigment proliferation and biological evolution

    CERN Document Server

    Michaelian, Karo

    2013-01-01

    The most important thermodynamic work performed by life today is the dissipation of the solar photon flux into heat through organic pigments in water. From this thermodynamic perspective, biological evolution is thus just the dispersal of organic pigments and water throughout Earth's surface, while adjusting the gases of Earth's atmosphere to allow the most intense part of the solar spectrum to penetrate the atmosphere and reach the surface to be intercepted by these pigments. The covalent bonding of atoms in organic pigments provides excited levels compatible with the energies of these photons. Internal conversion through vibrational relaxation to the ground state of these excited molecules when in water leads to rapid dissipation of the solar photons into heat, and this is the major source of entropy production on Earth. A non-linear irreversible thermodynamic analysis shows that the proliferation of organic pigments on Earth is a direct consequence of the pigments catalytic properties in dissipating the so...

  7. Efficiency at maximum power of a quantum Otto cycle within finite-time or irreversible thermodynamics.

    Science.gov (United States)

    Wu, Feilong; He, Jizhou; Ma, Yongli; Wang, Jianhui

    2014-12-01

    We consider the efficiency at maximum power of a quantum Otto engine, which uses a spin or a harmonic system as its working substance and works between two heat reservoirs at constant temperatures T(h) and T(c) (power based on these two different kinds of quantum systems are bounded from the upper side by the same expression η(mp)≤η(+)≡η(C)(2)/[η(C)-(1-η(C))ln(1-η(C))] with η(C)=1-T(c)/T(h) as the Carnot efficiency. This expression η(mp) possesses the same universality of the CA efficiency η(CA)=1-√(1-η(C)) at small relative temperature difference. Within the context of irreversible thermodynamics, we calculate the Onsager coefficients and show that the value of η(CA) is indeed the upper bound of EMP for an Otto engine working in the linear-response regime.

  8. Reversible and irreversible thermochromic phase transitions in single crystals of polydiacetylenes substituted with alkyl-urethanes

    Science.gov (United States)

    Koshihara, Shin-ya; Tokura, Yoshinori; Takeda, Kenji; Koda, Takao; Kobayashi, Akiko

    1990-06-01

    Reversible transitions between the two spectroscopically distinct phases (A and B phases) have been investigated for a new family of polydiacetylenes (PDAs) substituted with side groups of alkyl-urethane [-(CH2)4OCONH(CH2)n-1CH3:n =1-10]. Measurements of optical spectra as well as x-ray and calorimetric studies have revealed the first-order-like phase transitions in a series of PDAs with n=1-10 which are associated with an n-dependent thermal hysteresis ranging from 0 to 60 K in width. It has been found that the thermochromic changes become irreversible in all these PDAs once the hydrogen bond chains in the side groups are interrupted by heating beyond the polymer melting temperature.

  9. Exploring the optimal performances of irreversible single resonance energy selective electron refrigerators

    Science.gov (United States)

    Zhou, Junle; Chen, Lingen; Ding, Zemin; Sun, Fengrui

    2016-05-01

    Applying finite-time thermodynamics (FTT) and electronic transport theory, the optimal performances of irreversible single resonance energy selective electron (ESE) refrigerator are analyzed. The effects of heat leakage between two electron reservoirs on optimal performances are discussed. The influences of system operating parameters on cooling load, coefficient of performance (COP), figure of merit and ecological function are demonstrated using numerical examples. Comparative performance analyses among different objective functions show that performance characteristics at maximum ecological function and maximum figure of merit are of great practical significance. Combining the two optimization objectives of maximum ecological function and maximum figure of merit together, more specific optimal ranges of cooling load and COP are obtained. The results can provide some advices to the design of practical electronic machine systems.

  10. Nonlinear Gamow vectors, shock waves and irreversibility in optically nonlocal media

    CERN Document Server

    Gentilini, Silvia; Marcucci, Giulia; DelRe, Eugenio; Conti, Claudio

    2015-01-01

    Dispersive shock waves dominate wave-breaking phenomena in Hamiltonian systems. In the absence of loss, these highly irregular and disordered waves are potentially reversible. However, no experimental evidence has been given about the possibility of inverting the dynamics of a dispersive shock wave and turn it into a regular wave-front. Nevertheless, the opposite scenario, i.e., a smooth wave generating turbulent dynamics is well studied and observed in experiments. Here we introduce a new theoretical formulation for the dynamics in a highly nonlocal and defocusing medium described by the nonlinear Schroedinger equation. Our theory unveils a mechanism that enhances the degree of irreversibility. This mechanism explains why a dispersive shock cannot be reversed in evolution even for an arbitrarirly small amount of loss. Our theory is based on the concept of nonlinear Gamow vectors, i.e., power dependent generalizations of the counter-intuitive and hereto elusive exponentially decaying states in Hamiltonian sys...

  11. Graphical Analysis of PET Data Applied to Reversible and Irreversible Tracers

    Energy Technology Data Exchange (ETDEWEB)

    Logan, Jean

    1999-11-18

    Graphical analysis refers to the transformation of multiple time measurements of plasma and tissue uptake data into a linear plot, the slope of which is related to the number of available tracer binding sites. This type of analysis allows easy comparisons among experiments. No particular model structure is assumed, however it is assumed that the tracer is given by bolus injection and that both tissue uptake and the plasma concentration of unchanged tracer are monitored following tracer injection. The requirement of plasma measurements can be eliminated in some cases when a reference region is available. There are two categories of graphical methods which apply to two general types of ligands--those which bind reversibly during the scanning procedure and those which are irreversible or trapped during the time of the scanning procedure.

  12. Study on the irreversible thermodynamics of a marine engine exhaust-powered adsorption refrigerating system

    Science.gov (United States)

    Xie, Yingchun; Mei, Ning; Xu, Zhen

    2006-04-01

    This study investigates the heat and mass transfer mechanism of a marine engine exhaust-powered adsorption refrigerating system by using irreversible thermodynamics. The equations of entropy-production rate and the linear phenomenological equations of thermodynamic flux and force are established. The conventional experimental facilities of unit tube are developed and the phenomenological coefficients are obtained by fitting the experimental data. It is concluded that the thermodynamic process in the adsorbent bed is determined by the coupling effect of the heat and mass transfer; furthermore, the mass transfer is determined by the heat transfer. Taking some measures to increase heat transfer can improve the performance of the adsorption refrigerating system. The conclusions presented in this paper may be of value to the engineering applications of the system.

  13. Irreversibility in a unitary finite-rate protocol: the concept of internal friction

    Science.gov (United States)

    Çakmak, Selçuk; Altintas, Ferdi; Müstecaplıoğlu, Özgür E.

    2016-07-01

    The concept of internal friction, a fully quantum mechanical phenomena, is investigated in a simple, experimentally accessible quantum system in which a spin-1/2 is driven by a transverse magnetic field in a quantum adiabatic process. The irreversible production of the waste energy due to the quantum friction is quantitatively analyzed in a forward-backward unitary transform of the system Hamiltonian by using the quantum relative entropy between the actual density matrix obtained in a parametric transformation and the one in a reversible adiabatic process. Analyzing the role of total transformation time and the different pulse control schemes on the internal friction reveal the non-monotone character of the internal friction as a function of the total protocol time and the possibility for almost frictionless solutions in finite-time transformations.

  14. The irreversibility line of (Hg, Cr)Sr2CuO4+δ superconductor

    International Nuclear Information System (INIS)

    Superconducting (Hg, Cr)-1201 phase was synthesized with a nominal composition Hg0.7, Cr0.3Sr2CuO4+δ by solid state reaction method in vacuum-sealed quartz-tube. X-ray diffraction (XRD) analysis of the sample showed a tetragonal symmetry with lattice parameters a = 3.842 (2) A and c = 8.641 (5) A. Ac-susceptibility, dc-magnetization, and dc-resistivity measurements indicate a Tc of 60 K. The irreversibility line (IRL) was obtained from the merging point of the zero field cooled (ZFC) and field cooled (FC) magnetization measurements at several applied fields. The fit H =A(1 -T / Tc)n gave a value of 2.55 for the exponent n. (author)

  15. Metaphit irreversibly inhibits (/sup 3/H)threo-(+/-)-methylphenidate binding to rat striatal tissue

    Energy Technology Data Exchange (ETDEWEB)

    Schweri, M.M.; Jacobson, A.E.; Lessor, R.A.; Rice, K.C.

    1987-01-01

    Metaphit (1-(1-(3-isothiocyanatophenyl)cyclohexyl)-piperidine), a derivative of phencyclidine that contains an isothiocyanate group on the meta position of the aromatic ring, resembles its parent compound (phencyclidine) in its ability to inhibit the binding of the stimulant drug (/sup 3/H)threo-(+/-)-methylphenidate to crude synaptosomal membranes from rat striatal tissue (IC50 = 1.4 and 6.2 microM for phencyclidine and Metaphit, respectively). Unlike phencyclidine, however, Metaphit appears to inhibit binding of the radiolabeled stimulant in an irreversible manner, as the degree of inhibition of binding of the stimulant does not diminish when the Metaphit-treated tissue is subjected to repeated washings before determination of the binding of (/sup 3/H)threo-(+/-)-methylphenidate. This finding suggests that Metaphit may be a useful tool in the study of the molecular basis of stimulant action.

  16. Modelling plastic deformation of metals over a wide range of strain rates using irreversible thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Huang Mingxin; Rivera-Diaz-del-Castillo, Pedro E J; Zwaag, Sybrand van der [Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS, Delft (Netherlands); Bouaziz, Olivier, E-mail: mingxin.huang@arcelormittal.com [ArcelorMittal Maizieres, Research and Development, Voie Romaine-BP30320, 57283 Maizieres-les-Metz Cedex (France)

    2009-07-15

    Based on the theory of irreversible thermodynamics, the present work proposes a dislocation-based model to describe the plastic deformation of FCC metals over wide ranges of strain rates. The stress-strain behaviour and the evolution of the average dislocation density are derived. It is found that there is a transitional strain rate ({approx} 10{sup 4} s{sup -1}) over which the phonon drag effects appear, resulting in a significant increase in the flow stress and the average dislocation density. The model is applied to pure Cu deformed at room temperature and at strain rates ranging from 10{sup -5} to 10{sup 6} s{sup -1} showing good agreement with experimental results.

  17. Did nonlinear irreversible thermodynamics revolutionize the classical time conception of physics?

    Science.gov (United States)

    von Borzeszkowski, Horst-Heino; Wahsner, Renate

    1984-07-01

    From both physical and epistemological viewpoints, the following theses, which nowadays are often discussed in the literature, are examined: Nonlinear thermodynamics renders it possible to grasp evolutionary physical processes; for thermodynamics it introduces, instead of idealized reversible time, a directed time into physics; thus a science is established that is nearer to reality than classical physics. To analyze these theses, the relation of thermodynamics to dynamical physics is considered. In particular, it is demonstrated that, in classical as well as in modern thermodynamics, irreversibility is introduced via conditions which must be formulated in addition to the dynamical laws. To show the reason for this, the epistemological status of the physical time conception is analyzed, and its character as a physical measurement quantity is established.

  18. Percutaneous Irreversible Electroporation of Locally Advanced Pancreatic Carcinoma Using the Dorsal Approach: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Scheffer, Hester J., E-mail: hj.scheffer@vumc.nl; Melenhorst, Marleen C. A. M., E-mail: m.melenhorst@vumc.nl [VU University Medical Center, Department of Radiology and Nuclear Medicine (Netherlands); Vogel, Jantien A., E-mail: j.a.vogel@amc.uva.nl [Academic Medical Center, Department of Surgery (Netherlands); Tilborg, Aukje A. J. M. van, E-mail: a.vantilborg@vumc.nl [VU University Medical Center, Department of Radiology and Nuclear Medicine (Netherlands); Nielsen, Karin, E-mail: k.nielsen@vumc.nl; Kazemier, Geert, E-mail: g.kazemier@vumc.nl [VU University Medical Center, Department of Surgery (Netherlands); Meijerink, Martijn R., E-mail: mr.meijerink@vumc.nl [VU University Medical Center, Department of Radiology and Nuclear Medicine (Netherlands)

    2015-06-15

    Irreversible electroporation (IRE) is a novel image-guided ablation technique that is increasingly used to treat locally advanced pancreatic carcinoma (LAPC). We describe a 67-year-old male patient with a 5 cm stage III pancreatic tumor who was referred for IRE. Because the ventral approach for electrode placement was considered dangerous due to vicinity of the tumor to collateral vessels and duodenum, the dorsal approach was chosen. Under CT-guidance, six electrodes were advanced in the tumor, approaching paravertebrally alongside the aorta and inferior vena cava. Ablation was performed without complications. This case describes that when ventral electrode placement for pancreatic IRE is impaired, the dorsal approach could be considered alternatively.

  19. Irreversible Electroporation of Hepatic and Pancreatic Malignancies: Radiologic-Pathologic Correlation.

    Science.gov (United States)

    Gonzalez-Beicos, Aldo; Venkat, Shree; Songrug, Tanakorn; Poveda, Julio; Garcia-Buitrago, Monica; Poozhikunnath Mohan, Prasoon; Narayanan, Govindarajan

    2015-09-01

    Irreversible electroporation (IRE) is a novel therapy that has shown to be a feasible and promising alternative to conventional ablative techniques when treating tumors near vital structures or blood vessels. The clinical efficacy of IRE has been evaluated using established imaging criteria. This study evaluates the histologic and imaging response of hepatic and pancreatic malignancies that were surgically resected after IRE. In total, 12 lesions ablated with IRE were included, including 3 pancreatic carcinomas, 5 primary tumors of the liver, and 4 metastatic tumors of the liver. The rate of complete response to IRE was 25% based on the histologic evaluation of the resected tumors. Although treatment-related vessel wall changes were noted in several cases in histologic findings, there was no evidence of vascular luminal narrowing or obliteration in any of the specimens. The imaging response to IRE before surgical resection usually resulted in underestimation of disease burden when compared with the histologic response seen on the resected specimens.

  20. Irreversible thermodynamics of open chemical networks I: Emergent cycles and broken conservation laws

    CERN Document Server

    Polettini, Matteo

    2014-01-01

    In this and a companion paper we outline a general framework for the thermodynamic description of open chemical reaction networks, with special regard to metabolic networks regulating cellular physiology and biochemical functions. We first introduce closed networks ``in a box'', whose thermodynamics is subjected to strict physical constraints: the mass-action law, elementarity of processes, and detailed balance. We further digress on the role of solvents and on the seemingly unacknowledged property of network independence of free energy landscapes. We then open the system by assuming that the concentrations of certain substrate species (the chemostats) are fixed, whether because promptly regulated by the environment via contact with reservoirs, or because nearly constant in a time window. As a result, the system is driven out of equilibrium. A rich algebraic and topological structure ensues in the network of internal species: Emergent irreversible cycles are associated to nonvanishing affinities, whose symmet...

  1. Entropy Production and Irreversible Processes -from the perspective of continuous topological evolution.

    Directory of Open Access Journals (Sweden)

    Robert M. Kiehn

    2004-05-01

    Full Text Available Abstract: A concept of entropy production associated with continuous topological evolution is deduced (without statistics from the fact that Cartan-Hilbert 1-form of Action defines a non-equilibrium symplectic system of Pfaff Topological dimension 2n+2. The differential entropy, dS, is composed of the interior product of the non-canonical components of momentum with the components of the differential velocities. An irreversible process can describe entropy production in terms of continuous topological evolution to non-equilibrium but stationary states. An equilibrium system can be defined topologically as a Lagrange submanifold of the 2n+2 topological space, upon which the change in entropy by continuous topological evolution is zero, dSequil=0.

  2. Estimation of Separation of Electrolytes and Organic Compounds by Nanofiltration Membranes Using an Irreversible Thermodynamic Model

    Institute of Scientific and Technical Information of China (English)

    PallabGhosh

    2003-01-01

    Nanofiltration separation has become a popular technique for removing large organic molecules and inorganic substances from water. It is achieved by a combination of three mechanisms: electrostatic repulsion,sieving and diffusion. In the present work, a model based on irreversible thermodynamics is extended and used to estimate rejection of inorganic salts and organic substances. Binary systems are modeled, where the feed contains an ion that is much less permeable to the membrane as compared with the other ion. The two model parameters are estimated by fitting the model to the experimental data. Variation of these parameters with the composition of the feed is described by an empirical correlation. This work attempts to describe transport through the nanofiltration membranes bv a simple model.

  3. A novel alkylating agent Melflufen induces irreversible DNA damage and cytotoxicity in multiple myeloma cells.

    Science.gov (United States)

    Ray, Arghya; Ravillah, Durgadevi; Das, Deepika S; Song, Yan; Nordström, Eva; Gullbo, Joachim; Richardson, Paul G; Chauhan, Dharminder; Anderson, Kenneth C

    2016-08-01

    Our prior study utilized both in vitro and in vivo multiple myeloma (MM) xenograft models to show that a novel alkylator melphalan-flufenamide (Melflufen) is a more potent anti-MM agent than melphalan and overcomes conventional drug resistance. Here we examined whether this potent anti-MM activity of melflufen versus melphalan is due to their differential effect on DNA damage and repair signalling pathways via γ-H2AX/ATR/CHK1/Ku80. Melflufen-induced apoptosis was associated with dose- and time-dependent rapid phosphorylation of γ-H2AX. Melflufen induces γ-H2AX, ATR, and CHK1 as early as after 2 h exposure in both melphalan-sensitive and -resistant cells. However, melphalan induces γ-H2AX in melphalan-sensitive cells at 6 h and 24 h; no γ-H2AX induction was observed in melphalan-resistant cells even after 24 h exposure. Similar kinetics was observed for ATR and CHK1 in meflufen- versus melphalan-treated cells. DNA repair is linked to melphalan-resistance; and importantly, we found that melphalan, but not melflufen, upregulates Ku80 that repairs DNA double-strand breaks. Washout experiments showed that a brief (2 h) exposure of MM cells to melflufen is sufficient to initiate an irreversible DNA damage and cytotoxicity. Our data therefore suggest that melflufen triggers a rapid, robust, and an irreversible DNA damage which may account for its ability to overcome melphalan-resistance in MM cells. PMID:27098276

  4. Towards the creation of decellularized organ constructs using irreversible electroporation and active mechanical perfusion

    Directory of Open Access Journals (Sweden)

    Robertson John

    2010-12-01

    Full Text Available Abstract Background Despite advances in transplant surgery and general medicine, the number of patients awaiting transplant organs continues to grow, while the supply of organs does not. This work outlines a method of organ decellularization using non-thermal irreversible electroporation (N-TIRE which, in combination with reseeding, may help supplement the supply of organs for transplant. Methods In our study, brief but intense electric pulses were applied to porcine livers while under active low temperature cardio-emulation perfusion. Histological analysis and lesion measurements were used to determine the effects of the pulses in decellularizing the livers as a first step towards the development of extracellular scaffolds that may be used with stem cell reseeding. A dynamic conductivity numerical model was developed to simulate the treatment parameters used and determine an irreversible electroporation threshold. Results Ninety-nine individual 1000 V/cm 100-μs square pulses with repetition rates between 0.25 and 4 Hz were found to produce a lesion within 24 hours post-treatment. The livers maintained intact bile ducts and vascular structures while demonstrating hepatocytic cord disruption and cell delamination from cord basal laminae after 24 hours of perfusion. A numerical model found an electric field threshold of 423 V/cm under specific experimental conditions, which may be used in the future to plan treatments for the decellularization of entire organs. Analysis of the pulse repetition rate shows that the largest treated area and the lowest interstitial density score was achieved for a pulse frequency of 1 Hz. After 24 hours of perfusion, a maximum density score reduction of 58.5 percent had been achieved. Conclusions This method is the first effort towards creating decellularized tissue scaffolds that could be used for organ transplantation using N-TIRE. In addition, it provides a versatile platform to study the effects of pulse

  5. Fracture R-curve of a toughened epoxy adhesive as a function of irreversible degradation

    Energy Technology Data Exchange (ETDEWEB)

    Ameli, A. [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario, M5S 3G8 (Canada); Papini, M. [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario, M5B 2K3 (Canada); Spelt, J.K., E-mail: spelt@mie.utoronto.ca [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario, M5S 3G8 (Canada)

    2010-07-25

    Open-faced double cantilever beam (DCB) specimens of a toughened epoxy-aluminum adhesive system were degraded over a relatively wide range of temperature, relative humidity (RH) and exposure time, dried and tested to characterize the irreversible evolution of the mixed-mode fracture resistance curves (R-curves). The water diffusion properties of the bulk adhesive were modeled using an earlier sequential dual Fickian (SDF) model for the same adhesive in order to predict the adhesive water content. Three temporal stages of degradation possessing different R-curve and fracture surface characteristics were observed. In general, the steady-state critical strain energy release rate (G{sub cs}), the rate of toughening (dG{sub cr}/da) and the length of the rising part of the R-curve decreased with increasing exposure temperature, RH and water concentration, while the initiation G{sub c} (G{sub ci}) remained unchanged. It is hypothesized that crack initiation is governed by the properties of the epoxy matrix and that the toughening action of rubber particles does not become appreciable until after a certain amount of crack extension (more than about 50 {mu}m in the present case). The irreversible degradation of fracture toughness was found to be insensitive to the phase angle, which simplifies the construction of the fracture toughness envelope for a given level of degradation. These effects were incorporated into a new R-curve degradation model which has an application in the R-curve prediction for closed joints having nonuniform degradation.

  6. Thermomagnetic behaviour and compositional irreversibility on (Fe/Si){sub 3} multilayer films

    Energy Technology Data Exchange (ETDEWEB)

    Badía-Romano, L., E-mail: lbadia@unizar.es [Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, E-50009 Zaragoza (Spain); Departamento de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Rubín, J. [Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, E-50009 Zaragoza (Spain); Departamento de Ciencia de Materiales e Ingeniería Metalúrgica, Universidad de Zaragoza, E-50018 Zaragoza (Spain); Magén, C. [Departamento de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Laboratorio de Microscopías Avanzadas (LMA), Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, E-50018 Zaragoza (Spain); Fundación ARAID, E-50004 Zaragoza (Spain); Bartolomé, F. [Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, E-50009 Zaragoza (Spain); Departamento de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Sesé, J.; Ibarra, M.R. [Departamento de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Laboratorio de Microscopías Avanzadas (LMA), Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, E-50018 Zaragoza (Spain); Bartolomé, J. [Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, E-50009 Zaragoza (Spain); Departamento de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); and others

    2014-09-01

    This work presents the correlation between the morphology and magnetic properties of (Fe/Si){sub 3} multilayers with different Fe layer thicknesses and fixed Si spacer thickness in a broad temperature range (5irreversible thermal process as temperature increases from 300 to 450 K that is correlated to the formation of a ferromagnetic silicide phase. At higher temperature this phase transforms into a paramagnetic Fe–Si phase. - Highlights: • A thermomagnetic study on (Fe/Si){sub 3} multilayers is performed by in situ annealing. • We assess on the Fe layer thickness dependence, while the Si spacer is fixed. • 90° and AF interlayer exchange couplings are found depending on the Fe thickness. • We report an irreversible thermal process, correlated to chemical transformations. • The integrity of these (Fe/Si){sub 3} films is conserved just till T≈410K.

  7. Theophylline and salbutamol improve pulmonary function in patients with irreversible chronic obstructive pulmonary disease.

    Science.gov (United States)

    Thomas, P; Pugsley, J A; Stewart, J H

    1992-01-01

    To investigate the efficacy of bronchodilators in patients with irreversible chronic obstructive pulmonary disease (COPD), we conducted a double-blind, randomized, four-phase, crossover comparison between placebo, oral theophylline, inhaled salbutamol, and a combination of both drugs in 12 patients with stable COPD (mean age, 63 years) whose increase in forced expiratory volume in 1 s (FEV1) was less than or equal to 15 percent following 200 micrograms of inhaled salbutamol. Patients received two weeks of therapy with each of the test regimens. Both theophylline and salbutamol resulted in statistically significant improvement in FEV1, forced vital capacity (FVC), slow vital capacity (SVC), residual volume (RV), airway resistance (Raw), and maximum expiratory flow rate at 50 percent of vital capacity (V50). In most instances, there were no significant differences between theophylline and salbutamol. Combination therapy produced significantly greater improvement in FEV1, FVC, V50, Raw, and RV than either agent alone. The two drugs interacted in an additive fashion. Neither of the drugs, used singly, significantly reduced the severity or incidence of symptoms. The reduction in dyspnea and wheeze during combination therapy approached statistical significance (p = 0.06) and patient preference was significantly in favor of the combination regimen. None of the active treatments produced significantly more side effects than placebo. We conclude that theophylline and inhaled salbutamol produce significant, and approximately equal, improvement in pulmonary function in patients traditionally classified as suffering from "irreversible" COPD. The combination of theophylline and inhaled salbutamol generally results in additional improvement over that obtained with either drug used alone and this improvement is reflected by reduced symptomatology and treatment preference.

  8. A facile route for irreversible bonding of plastic-PDMS hybrid microdevices at room temperature.

    Science.gov (United States)

    Tang, Linzhi; Lee, Nae Yoon

    2010-05-21

    Plastic materials do not generally form irreversible bonds with poly(dimethylsiloxane) (PDMS) regardless of oxygen plasma treatment and a subsequent thermal process. In this paper, we perform plastic-PDMS bonding at room temperature, mediated by the formation of a chemically robust amine-epoxy bond at the interfaces. Various plastic materials, such as poly(methylmethacrylate) (PMMA), polycarbonate (PC), polyimide (PI), and poly(ethylene terephthalate) (PET) were adopted as choices for plastic materials. Irrespective of the plastic materials used, the surfaces were successfully modified with amine and epoxy functionalities, confirmed by the surface characterizations such as water contact angle measurements and X-ray photoelectron spectroscopy (XPS), and chemically robust and irreversible bonding was successfully achieved within 1 h at room temperature. The bonding strengths of PDMS with PMMA and PC sheets were measured to be 180 and 178 kPa, respectively, and their assemblies containing microchannel structures endured up to 74 and 84 psi (510 and 579 kPa) of introduced compressed air, respectively, without destroying the microdevices, representing a robust and highly stable interfacial bonding. In addition to microchannel-molded PDMS bonded with flat plastic substrates, microchannel-embossed plastics were also bonded with a flat PDMS sheet, and both types of bonded assemblies displayed sufficiently robust bonding, tolerating an intense influx of liquid whose per-minute injection volume was nearly 1000 to 2000 times higher than the total internal volume of the microchannel used. In addition to observing the bonding performance, we also investigated the potential of surface amine and epoxy functionalities as durable chemical adhesives by observing their storage-time-dependent bonding performances. PMID:20445880

  9. Clinical importance of digitized chest X-ray for detection of pulmonary infiltrations in bone marrow transplant patients during aplasia; Wertigkeit der digitalen Thoraxaufnahme bei der Detektion von Lungeninfiltraten knochenmarktransplantierten Patienten in der Aplasie

    Energy Technology Data Exchange (ETDEWEB)

    Weber, C.; Maas, R.; Steiner, P.; Kramer, J.; Bumann, D.; Buecheler, E. [Universitaetskrankenhaus Eppendorf, Hamburg (Germany). Abt. fuer Roentgendiagnostik; Zander, A.R. [Universitaetskrankenhaus Eppendorf, Hamburg (Germany). Zentrum fuer Knochenmarktransplantation

    1999-10-01

    Purpose: Evaluation of digitized chest X-ray for the detection of pulmonary infiltrations in bone marrow transplant patients during aplasia. Methods: Digitized chest X-rays of 40 patients (21 female, 19 male) with 'Fever of unknown origin' (FUO) were evaluated concerning radiological signs of pulmonary infiltrations and correlated to clinical findings, blood chemistry, microbiology and bronchoscopy. Additionally, an individual risk profile was established. Results: In 11/40 patients pulmonary infiltrations were detected in digitized chest X-rays (group 1). 10/11 developed an infectious pulmonary infiltration. 29/40 patients developed no pulmonary infiltration (group 2). When fever increased for the first time (initial chest X-ray) a sensitivity, specificity, positive and negative predictive value of 46%, 86%, 56%, 81% and for the chest X-rays in process of 61%, 79%, 68% and 73% was found. C-reactive protein and temperature increase occured statistically significantly earlier (p<0.05) in group 1 compared to group 2. The average latency of digital chest X-rays in comparison to c-reactive protein and temperature increase was 6 days. The incidence of risk factors was significantly higher in group 1 in comparison to group 2 (p<0.05). Conclusion: Digitized chest X-rays are not a reliable method for primary detection of pulmonary infiltrations after bone marrow transplantation. Individual risk factors have to be taken into consideration to indicate further diagnostic methods such as computed tomography at an earlier time. (orig.) [German] Ziel: Wertigkeit der digitalen Thoraxaufnahme bei der Detektion pulmonaler Infiltrate bei knochenmarktransplantierten Patienten in der Aplasie. Methoden: Digitale Thoraxaufnahmen von 40 Patienten (21 Frauen, 19 Maenner) in Aplasie mit Fieber unklarer Genese wurden nach Zeichen pulmonaler Infiltrate ausgewertet und mit klinischen, laborchemischen, mikrobiologischen und bronchoskopischen Befunden korreliert. Zusaetzlich wurde ein

  10. Interaction effect detected by compared of the irreversible and remanent initial magnetization curves in Ni-Cu-Zn ferrites

    OpenAIRE

    Goev, G.; Masheva, V.

    2013-01-01

    A new technique for estimation of magnetic interaction effects of initial magnetization curves has been proposed. It deals with remanence, and initial irreversible magnetization, curves. The method is applied for single-phase polycrystalline Ni0.85-xCu0.15ZnxFe2O4, (x = 0, 0.2, 0.4 and 0.6), which were synthesized by a standard ceramic technology. A study of the initial reversible and irreversible magnetization processes in ferrite materials was carried out. The field dependence of the irreve...

  11. Impact of pseudo-gap states on the pinning energy and irreversibility field of high temperature superconductors

    Directory of Open Access Journals (Sweden)

    Guy Deutscher

    2014-09-01

    Full Text Available The existence of pseudo-gap states at energies larger than the coherence energy scale is shown to be at the origin of the difficulties encountered in achieving strong vortex pinning in the high Tc cuprates. Reduction or elimination of the pseudo-gap states by overdoping is effective in increasing the condensation energy and the irreversibility field. In YBa2Cu3O7, a full BCS state, with a single energy scale, can be restored, leading to the highest known irreversibility field and pinning strength. In the bismuthates, the detrimental effect of the pseudo-gap states can only be mitigated to some extent by overdoping.

  12. Application of exergetic sustainable index to the quantum irreversible Diesel refrigerator cycles for 1D box system

    Science.gov (United States)

    Açıkkalp, Emin; Caner, Necmettin

    2015-04-01

    In this paper, an irreversible quantum Diesel refrigerator for a 1D-box system is described and analyzed. The exergetic sustainability index that is the rate of the exergy output from the system to the total exergetic losses including exergy destruction and exergy loss from the system is applied for the first time to an irreversible quantum engine. Other thermodynamic parameters including work input, cooling load, exergy destruction, COP and exergy efficiency are investigated according to the cycle temperatures and numerical results are presented.

  13. Se los por se lo

    Directory of Open Access Journals (Sweden)

    José Luis Rivarola

    1985-12-01

    Full Text Available El sistema de la conjugación "objetiva" plantea interesantesproblemas que fueron tratados en parte por K. Heger (1966 en suestudio comparativo del francés y del español. De la comparaciónse desprende, por ejemplo, que en español hay un cierto número deambigüedades que no permiten establecer un "paradigma tan completo y unívoco" como en el caso del francés. Dentro de estas ambigüedades se encuentran las que propicia el gramema se: "El morfema [gramema] se funciona no sólo como pronombre reflexivo, sinotambién como variante combinatoria del pronombre personal complemento indirecto de la tercera persona.

  14. por el Tribunal Constitucional chileno

    Directory of Open Access Journals (Sweden)

    Marisol Peña Torres

    2008-01-01

    Full Text Available La modificación introducida por la reforma constitucional de agosto de 1989 al artículo 5º de la Constitución chilena sentó un criterio decisivo en la incorporación del derecho internacional de los derechos humanos al ordenamiento jurídico interno. El artículo examina la jurisprudencia del Tribunal Constitucional antes y después de esa reforma distinguiendo entre la aplicación del Derecho Internacional de los Derechos Humanos por haberse invocado en la acción deducida y la aplicación de principios y criterios hermenéuticos extraídos del mismo.

  15. Sepsis neonatal por Estreptococos Pyogenes

    Directory of Open Access Journals (Sweden)

    Gilberto Rodríguez-Herrera

    2009-09-01

    Full Text Available Se presenta el caso de un paciente masculino, recién nacido a término adecuado para la edad gestacional, quien nace por parto vaginal, con el antecedente de fiebre en la madre durante el periodo de postparto inmediato. Los padres consultan a los 2 días de vida pues le notan dificultad respiratoria, hipoactividad y rechazo a la leche materna. El paciente se interna y se aborda como una sepsis. Durante su estancia en el servicio de neonatología del Hospital Nacional de Niños asocia fallo respiratorio que amerita ventilación mecánica asistida por varios días en diferentes ocasiones, derrame pleural exudativo, convulsiones de origen hipóxico isquémico. Con reporte de hemocultivos positivos por Estreptococos pyogenes. El Estreptococos pyogenes o estreptococo β-hemolνtico del grupo A, fue un problema en los comienzos del siglo pasado, siendo frecuente en las infecciones puerperales y del reciιn nacido. En la actualidad es un germen sumamente raro en los procesos de sepsis neonatal.2 La gravedad de la enfermedad causada por este microorganismo en el periodo neonatal varνa desde una onfalitis crónica de bajo grado a una septicemia, una meningitis fulminante y la muerte.1 El presente artículo pretende hacer un resumen del paciente, con su evolución clínica, radiológica y además ejemplificar todas las complicaciones que tuvimos con este germen tan poco frecuente en la actualidad en sepsis neonatal.

  16. Irreversibility analysis of non isothermal flat plate solar collectors for air heating with a dimensionless model; Analisis de las irreversibilidades en colectores solares de placas planas no isotermicos para calentamiento de aire utilizando un modelo adimensional

    Energy Technology Data Exchange (ETDEWEB)

    Bracamonte-Baran, Johane Hans; Baritto-Loreto, Miguel Leonardo [Universidad Central de Venezuela (Venezuela)]. E-mails: johanehb@gmail.com; johane.bracamonte@ucv.ve; miguel.baritto@ucv.ve

    2013-04-15

    The dimensionless model developed and validated by Baritto and Bracamonte (2012) for the thermal behavior of flat plate solar collector without glass cover is improved by adding the entropy balance equation in a dimensionless form. The model is solved for a wide range of aspect ratios and mass flow numbers. A parametric study is developed and the distribution of internal irreversibilities along the collector is analyzed. The influence of the design parameters on the entropy generation by fluid friction and heat transfer is analyzed and it is found that for certain combinations of these parameters optimal thermodynamic operation can be achieved. [Spanish] En el presente trabajo, el modelo adimensional desarrollado y validado por Baritto y Bracamonte (2012) para describir el comportamiento termico de colectores solares de placas planas sin cubierta transparente, se complementa con la ecuacion adimensional de balance de entropia para un elemento diferencial de colector solar. El modelo se resuelve para un amplio rango de valores de relaciones de aspecto y numero de flujo de masa. A partir de los resultados del modelo se desarrolla un analisis detallado de la influencia de estos parametros sobre la distribucion de irreversibilidades internas a lo largo del colector. Adicionalmente se estudia la influencia de estos parametros sobre los numeros de generacion de entropia por friccion viscosa, por transferencia de calor y total. Se encuentra que existen combinaciones de los parametros antes mencionados, para los cuales, la operacion del colector es termodinamicamente optima para numeros de flujo de masa elevados.

  17. Desajuste educativo por regiones en Colombia: ¿competencia por salarios o por puestos de trabajo?

    Directory of Open Access Journals (Sweden)

    Castillo Caicedo Maribel

    2007-08-01

    Full Text Available Este trabajo aporta una perspectiva del fenómeno de la sobreeducación,
    entendida como un desajuste por exceso, entre el nivel educativo alcanzado
    por el individuo y el exigido por el puesto de trabajo en el cual se
    desempeña; esto se debe a que existe una demanda laboral estrecha de
    puestos de trabajo para personas calificadas en Colombia. Se analizan las
    contribuciones empíricas existentes y el debate sobre las mismas; se
    examinan las teorías que permiten explicar la existencia de un desajuste
    educativo y se realiza una revisión de la literatura internacional y
    nacional sobre el tema. Adicionalmente, se plantean una serie de hipótesis
    para desarrollar un esquema que permita determinar el comportamiento
    del individuo en el fenómeno de la sobreeducación.

  18. Characteristics of meso-particles formed in coagulation process causing irreversible membrane fouling in the coagulation-microfiltration water treatment.

    Science.gov (United States)

    Ding, Q; Yamamura, H; Murata, N; Aoki, N; Yonekawa, H; Hafuka, A; Watanabe, Y

    2016-09-15

    In coagulation-membrane filtration water treatment processes, it is still difficult to determine the optimal coagulation condition to minimize irreversible membrane fouling. In microfiltration (MF), meso-particles (i.e., 20 nm-0.5 μm) are thought to play an important role in irreversible membrane fouling, especially their characteristics of particle number (PN) and zeta potential (ZP). In this study, a new nanoparticle tracker combined a high-output violet laser with a microscope was developed to identify the physicochemical characteristics of these microscopic and widely dispersed meso-particles. The effects of pH and coagulant dose on ZP and PN of micro-particles (i.e., >0.5 μm) and meso-particles were investigated, and then coagulation-MF tests were conducted. As the result, irreversible membrane fouling was best controlled for both types of membranes, while meso-particle ZP approached zero at around pH 5.5 for both types of natural water. Since PN was greatest under these conditions, ZP is more important in determining the extent of irreversible membrane fouling than PN. However, the acidic condition to neutralize meso-particles is not suitable for actual operation, as considering residual aluminum concentration, pipe corrosion, and chlorination efficiency. It is therefore necessary to investigate coagulants or other methods for the appropriate modification of meso-particle characteristics.

  19. Application of exergetic sustainability index to a nano-scale irreversible Brayton cycle operating with ideal Bose and Fermi gasses

    International Nuclear Information System (INIS)

    Highlights: • An irreversible Brayton cycle operating quantum gasses is considered. • Exergetic sustainability index is derived for nano-scale cycles. • Nano-scale effects are considered. • Calculation are conducted for irreversible cycles. • Numerical results are presented and discussed. - Abstract: In this study, a nano-scale irreversible Brayton cycle operating with quantum gasses including Bose and Fermi gasses is researched. Developments in the nano-technology cause searching the nano-scale machines including thermal systems to be unavoidable. Thermodynamic analysis of a nano-scale irreversible Brayton cycle operating with Bose and Fermi gasses was performed (especially using exergetic sustainability index). In addition, thermodynamic analysis involving classical evaluation parameters such as work output, exergy output, entropy generation, energy and exergy efficiencies were conducted. Results are submitted numerically and finally some useful recommendations were conducted. Some important results are: entropy generation and exergetic sustainability index are affected mostly for Bose gas and power output and exergy output are affected mostly for the Fermi gas by x. At the high temperature conditions, work output and entropy generation have high values comparing with other degeneracy conditions

  20. Finite time exergoeconomic performance optimization for an irreversible universal steady flow variable-temperature heat reservoir heat pump cycle model

    Directory of Open Access Journals (Sweden)

    Huijun Feng, Lingen Chen, Fengrui Sun

    2010-11-01

    Full Text Available An irreversible universal steady flow heat pump cycle model with variable-temperature heat reservoirs and the losses of heat-resistance and internal irreversibility is established by using the theory of finite time thermodynamics. The universal heat pump cycle model consists of two heat-absorbing branches, two heat-releasing branches and two adiabatic branches. Expressions of heating load, coefficient of performance (COP and profit rate of the universal heat pump cycle model are derived, respectively. By means of numerical calculations, heat conductance distributions between hot- and cold-side heat exchangers are optimized by taking the maximum profit rate as objective. There exist an optimal heat conductance distribution and an optimal thermal capacity rate matching between the working fluid and heat reservoirs which lead to a double maximum profit rate. The effects of internal irreversibility, total heat exchanger inventory, thermal capacity rate of the working fluid and heat capacity ratio of the heat reservoirs on the optimal finite time exergoeconomic performance of the cycle are discussed in detail. The results obtained herein include the optimal finite time exergoeconomic performances of endoreversible and irreversible, constant- and variable-temperature heat reservoir Brayton, Otto, Diesel, Atkinson, Dual, Miller and Carnot heat pump cycles.

  1. Application of exergetic sustainability index to a nano-scale irreversible Brayton cycle operating with ideal Bose and Fermi gasses

    Energy Technology Data Exchange (ETDEWEB)

    Açıkkalp, Emin, E-mail: eacikkalp@gmail.com [Department of Mechanical and Manufacturing Engineering, Engineering Faculty, Bilecik S.E. University, Bilecik (Turkey); Caner, Necmettin [Department of Chemistry, Faculty of Arts and Sciences, Eskisehir Osmangazi University, Eskisehir (Turkey)

    2015-09-25

    Highlights: • An irreversible Brayton cycle operating quantum gasses is considered. • Exergetic sustainability index is derived for nano-scale cycles. • Nano-scale effects are considered. • Calculation are conducted for irreversible cycles. • Numerical results are presented and discussed. - Abstract: In this study, a nano-scale irreversible Brayton cycle operating with quantum gasses including Bose and Fermi gasses is researched. Developments in the nano-technology cause searching the nano-scale machines including thermal systems to be unavoidable. Thermodynamic analysis of a nano-scale irreversible Brayton cycle operating with Bose and Fermi gasses was performed (especially using exergetic sustainability index). In addition, thermodynamic analysis involving classical evaluation parameters such as work output, exergy output, entropy generation, energy and exergy efficiencies were conducted. Results are submitted numerically and finally some useful recommendations were conducted. Some important results are: entropy generation and exergetic sustainability index are affected mostly for Bose gas and power output and exergy output are affected mostly for the Fermi gas by x. At the high temperature conditions, work output and entropy generation have high values comparing with other degeneracy conditions.

  2. Disinfection procedures: their efficacy and effect on dimensional accuracy and surface quality of an irreversible hydrocolloid impression material.

    LENUS (Irish Health Repository)

    Rentzia, A

    2011-02-01

    This study investigated the antibacterial efficacy and effect of 0.55% ortho-phthalaldehyde (Cidex OPA(®)) and 0.5% sodium hypochlorite (NaOCl) on the dimensional accuracy and surface quality of gypsum casts retrieved from an irreversible hydrocolloid impression material.

  3. High-frequency irreversible electroporation (H-FIRE for non-thermal ablation without muscle contraction

    Directory of Open Access Journals (Sweden)

    Arena Christopher B

    2011-11-01

    Full Text Available Abstract Background Therapeutic irreversible electroporation (IRE is an emerging technology for the non-thermal ablation of tumors. The technique involves delivering a series of unipolar electric pulses to permanently destabilize the plasma membrane of cancer cells through an increase in transmembrane potential, which leads to the development of a tissue lesion. Clinically, IRE requires the administration of paralytic agents to prevent muscle contractions during treatment that are associated with the delivery of electric pulses. This study shows that by applying high-frequency, bipolar bursts, muscle contractions can be eliminated during IRE without compromising the non-thermal mechanism of cell death. Methods A combination of analytical, numerical, and experimental techniques were performed to investigate high-frequency irreversible electroporation (H-FIRE. A theoretical model for determining transmembrane potential in response to arbitrary electric fields was used to identify optimal burst frequencies and amplitudes for in vivo treatments. A finite element model for predicting thermal damage based on the electric field distribution was used to design non-thermal protocols for in vivo experiments. H-FIRE was applied to the brain of rats, and muscle contractions were quantified via accelerometers placed at the cervicothoracic junction. MRI and histological evaluation was performed post-operatively to assess ablation. Results No visual or tactile evidence of muscle contraction was seen during H-FIRE at 250 kHz or 500 kHz, while all IRE protocols resulted in detectable muscle contractions at the cervicothoracic junction. H-FIRE produced ablative lesions in brain tissue that were characteristic in cellular morphology of non-thermal IRE treatments. Specifically, there was complete uniformity of tissue death within targeted areas, and a sharp transition zone was present between lesioned and normal brain. Conclusions H-FIRE is a feasible technique for

  4. Irreversible thermochromic response of RF sputtered nanocrystalline BaWO4 films for smart window applications

    Science.gov (United States)

    Anil Kumar, C.; Santhosh Kumar, T.; Pamu, D.

    2015-10-01

    We report irreversible thermochromic behaviour of BaWO4 (BWO) films for the first time. BWO films have been deposited at different substrate temperatures (RT, 200, 400, 600 and 800 °C) using RF magnetron sputtering in pure argon plasma. BWO films deposited at 800 °C exhibit crystalline nature. Also, BWO films deposited in the temperature range of 400 - 600 °C exhibit WO3 as a secondary phase and its weight percentage decreases with an increase in deposition temperature, whereas the films deposited at 800 °C exhibited pure tetragonal phase. FESEM images revealed that as the average particle sizes of the films are higher as compared with the thickness of the films and is explained based on Avrami type nucleation and growth. The transmittance of the films decreases with an increase in deposition temperature up to 600 °C and increases thereafter. Films deposited at 600 °C show ≤ 20% transmittance, looking at the films deposited at room temperature and 800 °C exhibits 90 and 70%, respectively. The refractive index and extinction coefficient of the films show profound dependence on crystallinity and packing density. The optical bandgap of BWO films increases significantly with an increase in O2% during the deposition. The optical bandgap of the BWO films deposited at different temperatures in pure argon plasma, are in the range of 3.7 to 3.94 eV whereas the films deposited at 600 °C under different O2 plasma are in the range of 3.6 - 4.5 eV. The formations of colour centres are associated with the oxygen vacancies, which are clearly seen from the optical bandgap studies. The observed irreversible thermochromic behaviour in BWO films is attributed to the presence of oxygen vacancies that arises due to the electrons trapped at oxygen vacancies causing an inter valence charge transfer of W5+ to W6+ and is confirmed through the change in the optical density (ΔOD). Further, the Raman spectra are being used to quantify the presence of oxygen vacancies and the

  5. Energy Efficient Operation of Distillation Columns and a Reactor Applying Irreversible Thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Koeijer, Gelein M. de

    2002-05-01

    In this thesis the entropy production rates of diabatic distillation columns and a SO{sub 2} converter were minimised. This is the same as maximising the second law energy efficiency of the systems. The development of chemical industry can be made more sustainable by knowing this minimum. We found that the entropy production rate of distillation could be reduced up to 50 %. In order to achieve this reduction, heat exchangers were added on each tray. The characteristics of an optimum distillation column were presented. Furthermore, the entropy production rate of a SO{sub 2} converter was reduced with 16.7 % by altering the heights of catalytic beds, transfer areas of heat exchangers, and temperature differences over heat exchangers. These reductions show that there is still a large improvement potential in chemical industry. By applying the improved operations the world oil production can be reduced in the order of magnitude of 1 %. A similar reduction in the emission of the greenhouse gas CO{sub 2} can be expected. For deriving the entropy production rate in a systematic manner the theory of irreversible thermodynamics was useful. A simpler and a more complicated equation for the entropy production rate of distillation were derived. The simpler equation used only one force-flux product. It was suitable for minimisation of the entropy production rate of columns with the assumption of equilibrium between the outlets on each tray. The more complicated equation was able to describe satisfactorily the entropy production rate of an experimental column that separated the non-ideal mixture water-ethanol. It was next used to derive an extended set of transport equations for distillation, that includes the interface and the Soret effect (or thermal diffusion). Finally, irreversible thermodynamics was used to describe the contribution to the entropy production rate of heat transfer in heat exchangers. This contribution had a significant impact on the results of the

  6. Irreversible thermochromic response of RF sputtered nanocrystalline BaWO4 films for smart window applications

    Directory of Open Access Journals (Sweden)

    C. Anil Kumar

    2015-10-01

    Full Text Available We report irreversible thermochromic behaviour of BaWO4 (BWO films for the first time. BWO films have been deposited at different substrate temperatures (RT, 200, 400, 600 and 800 °C using RF magnetron sputtering in pure argon plasma. BWO films deposited at 800 °C exhibit crystalline nature. Also, BWO films deposited in the temperature range of 400 - 600 °C exhibit WO3 as a secondary phase and its weight percentage decreases with an increase in deposition temperature, whereas the films deposited at 800 °C exhibited pure tetragonal phase. FESEM images revealed that as the average particle sizes of the films are higher as compared with the thickness of the films and is explained based on Avrami type nucleation and growth. The transmittance of the films decreases with an increase in deposition temperature up to 600 °C and increases thereafter. Films deposited at 600 °C show ≤ 20% transmittance, looking at the films deposited at room temperature and 800 °C exhibits 90 and 70%, respectively. The refractive index and extinction coefficient of the films show profound dependence on crystallinity and packing density. The optical bandgap of BWO films increases significantly with an increase in O2% during the deposition. The optical bandgap of the BWO films deposited at different temperatures in pure argon plasma, are in the range of 3.7 to 3.94 eV whereas the films deposited at 600 °C under different O2 plasma are in the range of 3.6 - 4.5 eV. The formations of colour centres are associated with the oxygen vacancies, which are clearly seen from the optical bandgap studies. The observed irreversible thermochromic behaviour in BWO films is attributed to the presence of oxygen vacancies that arises due to the electrons trapped at oxygen vacancies causing an inter valence charge transfer of W5+ to W6+ and is confirmed through the change in the optical density (ΔOD. Further, the Raman spectra are being used to quantify the presence

  7. Irreversible thermochromic response of RF sputtered nanocrystalline BaWO4 films for smart window applications

    International Nuclear Information System (INIS)

    We report irreversible thermochromic behaviour of BaWO4 (BWO) films for the first time. BWO films have been deposited at different substrate temperatures (RT, 200, 400, 600 and 800 °C) using RF magnetron sputtering in pure argon plasma. BWO films deposited at 800 °C exhibit crystalline nature. Also, BWO films deposited in the temperature range of 400 - 600 °C exhibit WO3 as a secondary phase and its weight percentage decreases with an increase in deposition temperature, whereas the films deposited at 800 °C exhibited pure tetragonal phase. FESEM images revealed that as the average particle sizes of the films are higher as compared with the thickness of the films and is explained based on Avrami type nucleation and growth. The transmittance of the films decreases with an increase in deposition temperature up to 600 °C and increases thereafter. Films deposited at 600 °C show ≤ 20% transmittance, looking at the films deposited at room temperature and 800 °C exhibits 90 and 70%, respectively. The refractive index and extinction coefficient of the films show profound dependence on crystallinity and packing density. The optical bandgap of BWO films increases significantly with an increase in O2% during the deposition. The optical bandgap of the BWO films deposited at different temperatures in pure argon plasma, are in the range of 3.7 to 3.94 eV whereas the films deposited at 600 °C under different O2 plasma are in the range of 3.6 - 4.5 eV. The formations of colour centres are associated with the oxygen vacancies, which are clearly seen from the optical bandgap studies. The observed irreversible thermochromic behaviour in BWO films is attributed to the presence of oxygen vacancies that arises due to the electrons trapped at oxygen vacancies causing an inter valence charge transfer of W5+ to W6+ and is confirmed through the change in the optical density (ΔOD). Further, the Raman spectra are being used to quantify the presence of oxygen

  8. Tracking inorganic foulants irreversibly accumulated on low-pressure membranes for treating surface water.

    Science.gov (United States)

    Yamamura, Hiroshi; Kimura, Katsuki; Higuchi, Kumiko; Watanabe, Yoshimasa; Ding, Qing; Hafuka, Akira

    2015-12-15

    While low-pressure membrane filtration processes (i.e., microfiltration and ultrafiltration) can offer precise filtration than sand filtration, they pose the problem of reduced efficiency due to membrane fouling. Although many studies have examined membrane fouling by organic substances, there is still not enough data available concerning membrane fouling by inorganic substances. The present research investigated changes in the amounts of inorganic components deposited on the surface of membrane filters over time using membrane specimens sampled thirteen times at arbitrary time intervals during pilot testing in order to determine the mechanism by which irreversible fouling by inorganic substances progresses. The experiments showed that the inorganic components that primarily contribute to irreversible fouling vary as filtration continues. It was discovered that, in the initial stage of operation, the main membrane-fouling substance was iron, whereas the primary membrane-fouling substances when operation finished were manganese, calcium, and silica. The amount of iron accumulated on the membrane increased up to the thirtieth day of operation, after which it reached a steady state. After the accumulation of iron became static, subsequent accumulation of manganese was observed. The fact that the removal rates of these inorganic components also increased gradually shows that the size of the exclusion pores of the membrane filter narrows as operation continues. Studying particle size distributions of inorganic components contained in source water revealed that while many iron particles are approximately the same size as membrane pores, the fraction of manganese particles slightly smaller than the pores in diameter was large. From these results, it is surmised that iron particles approximately the same size as the pores block them soon after the start of operation, and as the membrane pores narrow with the development of fouling, they become further blocked by manganese

  9. Clonagem de canistel por estaquia

    Directory of Open Access Journals (Sweden)

    Fernando Marcelo Chiamolera

    2014-09-01

    Full Text Available O canistel é nativo do sul do México e América Central e seus frutos apresentam elevado teor de carotenoides e vitamina A. Sua propagação é feita via sementes, resultando em considerável variabilidade genética entre os indivíduos, sendo a propagação vegetativa preferível, a fim de fixar características desejáveis. Assim, o objetivo deste trabalho foi avaliar a propagação vegetativa por estaquia de ramos semi-herbáceos de canistel, em função de quatro genótipos e quatro concentrações de AIB. Foram utilizadas estacas semiherbáceas apicais, mantidas com um par de folhas, sob nebulização intermitente, por 120 dias. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 4×4 (genótipos de canistel × concentrações de AIB, com quatro repetições e dez estacas por parcela. Foram avaliados a porcentagem de sobrevivência, a retenção foliar, o enraizamento, o calejamento, o número e o comprimento médio de raízes por estaca. O genótipo PC-1 foi superior aos demais, em todas as variáveis avaliadas, com destaque para o enraizamento das estacas, superior a 60%. As concentrações de AIB (0; 1.000; 3.000 e 5.000 mg L-1 não influenciaram na sobrevivência, retenção foliar e enraizamento das estacas, mas aumentaram o número e o comprimento de raízes em relação ao tratamento-controle (sem AIB. Há diferença na capacidade de enraizamento das estacas entre os genótipos de canistel, sendo a melhor resposta obtida com PC-1. A concentração de 3.000 mg L-1 de AIB resulta em maior número e comprimento de raízes nas estacas de canistel.

  10. Once mil metros por segundo

    OpenAIRE

    2012-01-01

    Esta exposición es una ventana hacia el mundo de la Ciencia Ficción. Los sueños de escritores extraordinarios, personajes, lugares, máquinas y robots que cada día están más cerca de nuestra cotidianidad gracias a los avances de la ciencia y la tecnología hacen parte de la muestra itinerante por las sedes de la Universidad Nacional. El visitante puede recorrer los diferentes géneros que constituyen este género literario, además de conocer sus principales representantes. Así mismo se explor...

  11. Sepsis neonatal por Estreptococos Pyogenes

    OpenAIRE

    Gilberto Rodríguez-Herrera; Cinthya Ramírez-Navarro

    2009-01-01

    Se presenta el caso de un paciente masculino, recién nacido a término adecuado para la edad gestacional, quien nace por parto vaginal, con el antecedente de fiebre en la madre durante el periodo de postparto inmediato. Los padres consultan a los 2 días de vida pues le notan dificultad respiratoria, hipoactividad y rechazo a la leche materna. El paciente se interna y se aborda como una sepsis. Durante su estancia en el servicio de neonatología del Hospital Nacional de Niños asocia fallo respir...

  12. Miasis ocular por Oestrus ovis

    Directory of Open Access Journals (Sweden)

    María Beltrán F

    2006-01-01

    Full Text Available Se presentan tres casos de miasis ocular (dos adultos y un niñoprocedentes de zonas ganaderas de la provincia de Huaura,departamento de Lima,que acudieron al Hospital Regional de Huacho por presentar el ojo rojo,fotofobia, edema palpebral y sensación de cuerpo extraño;se extrajeron larvas adheridas al canto interno del ojo,las cuales se recibieron en el Instituto Nacional de Salud y fueron identificadas como Oestrus ovis .

  13. Folate Conjugated Cellulose Nanocrystals Potentiate Irreversible Electroporation-induced Cytotoxicity for the Selective Treatment of Cancer Cells.

    Science.gov (United States)

    Colacino, Katelyn R; Arena, Christopher B; Dong, Shuping; Roman, Maren; Davalos, Rafael V; Lee, Yong W

    2015-12-01

    Cellulose nanocrystals are rod-shaped, crystalline nanoparticles that have shown prom-ise in a number of industrial applications for their unique chemical and physical properties. However, investigations of their abilities in the biomedical field are limited. The goal of this study is to show the potential use of folic acid-conjugated cellulose nanocrystals in the potentiation of irreversible electroporation-induced cell death in folate receptor (FR)-positive cancers. We optimized key pulse parameters including pulse duration, intensity, and incubation time with nanoparticles prior to electroporation. FR-positive cancer cells, KB and MDA-MB-468, were preincubated with cellulose nanocrystals (CNCs) conjugated with the targeting molecule folic acid (FA), 10 and 20 min respectively, prior to application of the optimized pulse electric field (PEF), 600 and 500 V/cm respectively. We have shown cellulose nanocrystals' ability to potentiate a new technique for tumor ablation, irreversible electroporation. Pre-incubation with FA-conjugated CNCs (CNC-FA) has shown a significant increase in cytotoxicity induced by irreversible electroporation in FR-positive cancer cells, KB and MDA-MB-468. Non-targeted CNCs (CNC-COOH) did not potentiate IRE when preincubated at the same parameters as previously stated in these cell types. In addition, CNC-FA did not potentiate irreversible electroporation-induced cytotoxicity in a FR-negative cancer cell type, A549. Without changing irreversible electroporation parameters it is possible to increase the cytotoxic effect on FR-positive cancer cells by exploiting the specific binding of FA to the FR, while not causing further damage to FR-negative tissue. PMID:24750004

  14. Polioencefalomalacia experimental em bovinos induzida por toxicose por enxofre

    Directory of Open Access Journals (Sweden)

    Paulo H.J. Cunha

    2011-01-01

    Full Text Available O presente trabalho teve como objetivos avaliar os sinais clínicos, as concentrações do sulfeto de hidrogênio ruminal e as alterações anatomopatológicas associadas à intoxicação experimental por enxofre em bovinos. Foram utilizados dez bezerros mestiços leiteiros, sendo que quatro bovinos ingeriram ração sem sulfato de sódio (G1 e seis consumiram ração com sulfato de sódio (G2. Exames clínicos (temperatura retal, frequência cardíaca e respiratória e motricidade ruminal e laboratoriais (hemograma, fibrinogênio, proteína plasmática, pH do fluido ruminal, concentração do sulfeto de hidrogênio ruminal, líquido cerebrospinal e histopatológico foram realizados. A temperatura retal, frequência cardíaca, hemograma, fibrinogênio, proteína plasmática, pH do fluido ruminal e os valores do líquido cerebrospinal estavam dentro dos valores de referência para a espécie. Taquipnéia, hipomotricidade ruminal e elevados valores de sulfeto de hidrogênio ruminal foram observados nos bezerros do grupo G2. Um bezerro do grupo G2 apresentou sinais neurológicos e lesões histopatológicas de PEM. Dois animais de cada grupo foram eutanasiados. Lesões microscópicas foram observadas nos bezerros do G2. Histologicamente as alterações observadas foram necrose neuronal cortical e lesões hemorrágicas nos núcleos basais, tálamo, mesencéfalo, ponte e bulbo. O protocolo experimental constituído por uma dieta rica em carboidrato de alta fermentação, baixa quantidade de fibra efetiva e altos níveis de enxofre (0,52% ocasionou alterações clinicas e histológicas e elevadas concentrações de sulfeto de hidrogênio ruminal compatíveis com quadro de intoxicação por enxofre.

  15. toxicidad neuroendocrina inducida por cadmio

    Directory of Open Access Journals (Sweden)

    A Romero

    2008-01-01

    Full Text Available El cadmio es un agente químico tóxico importante debido a su creciente nivel en el medio ambiente como resultado de prácticas industriales y agrícolas. Como perturbador endocrino, el cadmio modifica la secreción de hormonas hipofisarias. Los efectos indirectos del cadmio provocan la generación de especies reactivas de oxígeno y reducen la actividad de las proteínas implicadas en las defensas antioxidantes. La melatonina es conocida como un potente antioxidante, scavenger de radicales libres y quelante de metales sintetizada en la glándula pineal. De esta manera, las acciones antioxidantes de esta indolamina protegen frente a la peroxidación lipídica y el daño oxidativo de los radicales y de sus productos tóxicos. Los trabajos recopilados en esta revisión ponen de manifiesto la capacidad antioxidante de la melatonina y, por lo tanto, su posible papel protector frente a la toxicidad del cadmio en lo que se refiere al estrés oxidativo y peroxidación lipídica inducidos por la exposición a este metal.

  16. Hipoglucemia inducida por carcinoma adrenal

    Directory of Open Access Journals (Sweden)

    Jimena Soutelo

    2013-08-01

    Full Text Available El carcinoma suprarrenal es una neoplasia maligna infrecuente y de mal pronóstico. La presentación clínica más común es originada por la producción hormonal excesiva, mientras que el desarrollo de hipoglucemia sintomática es excepcional. Presentamos el caso de una mujer de 37 años que ingresó al hospital por síntomas de hipoglucemias graves, hipertensión arterial, hipopotasemia y amenorrea secundaria. En el laboratorio se halló hipoglucemia con insulina inhibida y niveles de andrógenos en rango tumoral. La tomografía computarizada (TC de abdomen y pelvis mostró voluminosa formación heterogénea de aspecto sólido sin plano de clivaje con respecto al parénquima hepático e intenso realce con contraste. Luego de la extirpación de la masa retroperitoneal, evolucionó con valores de glucemia y potasemia normales, estabilizó la presión arterial y recuperó los ciclos menstruales.

  17. The Effect of Irreversible Electroporation on the Femur: Experimental Study in a Rabbit Model.

    Science.gov (United States)

    Song, Yue; Zheng, Jingjing; Yan, Mingwei; Ding, Weidong; Xu, Kui; Fan, Qingyu; Li, Zhao

    2015-01-01

    Irreversible electroporation (IRE) is a novel ablation method that has been tested in humans with lung, prostate, kidney, liver, lymph node and presacral cancers. As a new non-thermal treatment, the use of IRE to ablate tumors in the musculoskeletal system might reduce the incidence of fractures. We aimed to determine the ablation threshold of cortical bone and to evaluate the medium- and long-term healing process and mechanical properties of the femur in a rabbit model post-IRE ablation. The ablation threshold of cortical bone was between 1090 V/cm and 1310 V/cm (120 pulses). IRE-ablated femurs displayed no detectable fracture but did exhibit signs of recovery, including osteoblast regeneration, angiogenesis and bone remodeling. In the ablation area, revascularization appeared at 4 weeks post-IRE. Osteogenic activity peaked 8 weeks post-IRE and remained high at 12 weeks. The mechanical strength decreased briefly 4 weeks post-IRE but returned to normal levels within 8 weeks. Our experiment revealed that IRE ablation preserved the structural integrity of the bone cortex, and the ablated bone was able to regenerate rapidly. IRE may hold unique promise for in situ bone tissue ablation because rapid revascularization and active osteogenesis in the IRE ablation area are possible. PMID:26655843

  18. Treatment planning of electroporation-based medical interventions: electrochemotherapy, gene electrotransfer and irreversible electroporation

    International Nuclear Information System (INIS)

    In recent years, cancer electrochemotherapy (ECT), gene electrotransfer for gene therapy and DNA vaccination (GET) and tissue ablation with irreversible electroporation (IRE) have all entered clinical practice. We present a method for a personalized treatment planning procedure for ECT, GET and IRE, based on medical image analysis, numerical modelling of electroporation and optimization with the genetic algorithm, and several visualization tools for treatment plan assessment. Each treatment plan provides the attending physician with optimal positions of electrodes in the body and electric pulse parameters for optimal electroporation of the target tissues. For the studied case of a deep-seated tumour, the optimal treatment plans for ECT and IRE require at least two electrodes to be inserted into the target tissue, thus lowering the necessary voltage for electroporation and limiting damage to the surrounding healthy tissue. In GET, it is necessary to place the electrodes outside the target tissue to prevent damage to target cells intended to express the transfected genes. The presented treatment planning procedure is a valuable tool for clinical and experimental use and evaluation of electroporation-based treatments. (paper)

  19. Electric Ablation with Irreversible Electroporation (IRE) in Vital Hepatic Structures and Follow-up Investigation.

    Science.gov (United States)

    Chen, Xinhua; Ren, Zhigang; Zhu, Tongyin; Zhang, Xiongxin; Peng, Zhiyi; Xie, Haiyang; Zhou, Lin; Yin, Shengyong; Sun, Junhui; Zheng, Shusen

    2015-01-01

    Irreversible electroporation (IRE) with microsecond-pulsed electric fields (μsPEFs) can effectively ablate hepatocellular carcinomas in animal models. This preclinical study evaluates the feasibility and safety of IRE on porcine livers. Altogether, 10 pigs were included. Computed tomography (CT) was used to guide two-needle electrodes that were inserted near the hilus hepatis and gall bladder. Animals were followed-up at 2 hours and at 2, 7 and 14 days post-treatment. During and after μsPEF ablation, electrocardiographs found no cardiovascular events, and contrast CT found no portal vein thrombosis. There was necrosis in the ablation zone. Mild cystic oedema around the gall bladder was found 2 hours post-treatment. Pathological studies showed extensive cell death. There was no large vessel damage, but there was mild endothelial damage in some small vessels. Follow-up liver function tests and routine blood tests showed immediate liver function damage and recovery from the damage, which correlated to the pathological changes. These results indicate that μsPEF ablation affects liver tissue and is less effective in vessels, which enable μsPEFs to ablate central tumour lesions close to the hilus hepatis and near large vessels and bile ducts, removing some of the limitations and contraindications of conventional thermal ablation. PMID:26549662

  20. In vivo non-thermal irreversible electroporation impact on rat liver galvanic apparent internal resistance

    International Nuclear Information System (INIS)

    Non-thermal irreversible electroporation (NTIRE) is a biophysical phenomenon which involves application of electric field pulses to cells or tissues, causing certain rearrangements in the membrane structure leading to cell death. The treated tissue ac impedance changes induced by electroporation were shown to be the indicators for NTIRE efficiency. In a previous study we characterized in vitro tissue galvanic apparent internal resistance (GAIR) changes due to NTIRE. Here we describe an in vivo study in which we monitored the GAIR changes of a rat liver treated by NTIRE. Electrical pulses were delivered through the same Zn/Cu electrodes by which GAIR was measured. GAIR was measured before and for 3 h after the treatment at 15 min intervals. The results were compared to the established ac bioimpedance measurement method. A decrease of 33% was measured immediately after the NTIRE treatment and a 40% decrease was measured after 3 h in GAIR values; in the same time 40% and 47% decrease respectively were measured by ac bioimpedance analyses. The temperature increase due to the NTIRE was only 0.5 deg. C. The results open the way for an inexpensive, self-powered in vivo real-time NTIRE effectiveness measurement.

  1. Local Control of Perivascular Malignant Liver Lesions Using Percutaneous Irreversible Electroporation: Initial Experiences

    International Nuclear Information System (INIS)

    PurposeThis study was designed to assess efficacy and safety in the treatment of perivascular malignant liver lesions using percutaneous, computed tomography (CT)-guided irreversible electroporation (IRE).MethodsFourteen patients (mean age 58 ± 11 years) with 18 malignant liver lesions were consecutively enrolled in this study. IRE was performed in patients not eligible for surgery and lesions abutting large vessels or bile ducts. Follow-up exams were performed using multislice-CT (MS-CT) or MRI.ResultsMedium lesion diameter was 20 ± 5 mm. Ten of 14 (71 %) were successfully treated with no local recurrence to date (mean follow-up 388 ± 160 days). One case left initial tumor control unclear and additional RFA was performed 4 weeks after IRE. Complications occurred in 4 of 14 (29 %) cases. In one case, intervention was terminated and abdominal bleeding required laparotomy. In two cases, a postinterventional hematothorax required intervention. In another case, abdominal bleeding could be managed conservatively. No complications related to the bile ducts occurred.ConclusionsPercutaneous IRE seems to be effective in perivascular lesions but is associated with a higher complication rate compared with thermoablative techniques

  2. Irreversible Electroporation as an Effective Technique for Ablating Human Metastatic Osteosarcoma.

    Science.gov (United States)

    Harris, Jamie C; Chen, Allen; Macias, Virgilia; Mahon, Brett; Chiu, Bill; Pillai, Srikumar

    2016-04-01

    Irreversible electroporation (IRE) induces apoptosis in tumor cells with electric energy, allowing treatment of unresectable tumors. One potential application is metastatic osteosarcoma (OS) in the pediatric population. A 12-year-old underwent thoracotomy with resection of metastatic OS. IRE was applied to 1 resected tumor section. Using 2 probes, 100 pulses with width of 90 ms were delivered. Efficacy was measured by increase in current draw during treatment. The treated sample was analyzed with hematoxylin and eosin and transmission electron microscopy. Default voltage of 1800 kV was ineffective. Voltage of 2700 kV caused excessive current draw and was aborted to prevent thermal injury. At 2200 kV, current draw rise was 9 amps, signifying successful treatment. Untreated specimen showed viable OS, normal surrounding lung tissue. Treated tumor had edema within the tumor and in surrounding lung tissue, with intra-alveolar hemorrhage and cellular architecture destruction. There was also evidence for cellular destruction such as disruption of lipid bilayer and release of intracellular fluid. Optimal voltage for treatment was 2200 kV, likely higher due to electrical conduction variation in the aerated lung. IRE may be an option for pediatric patients with unresectable metastatic OS. PMID:26950088

  3. Treatment planning of electroporation-based medical interventions: electrochemotherapy, gene electrotransfer and irreversible electroporation

    Science.gov (United States)

    Zupanic, Anze; Kos, Bor; Miklavcic, Damijan

    2012-09-01

    In recent years, cancer electrochemotherapy (ECT), gene electrotransfer for gene therapy and DNA vaccination (GET) and tissue ablation with irreversible electroporation (IRE) have all entered clinical practice. We present a method for a personalized treatment planning procedure for ECT, GET and IRE, based on medical image analysis, numerical modelling of electroporation and optimization with the genetic algorithm, and several visualization tools for treatment plan assessment. Each treatment plan provides the attending physician with optimal positions of electrodes in the body and electric pulse parameters for optimal electroporation of the target tissues. For the studied case of a deep-seated tumour, the optimal treatment plans for ECT and IRE require at least two electrodes to be inserted into the target tissue, thus lowering the necessary voltage for electroporation and limiting damage to the surrounding healthy tissue. In GET, it is necessary to place the electrodes outside the target tissue to prevent damage to target cells intended to express the transfected genes. The presented treatment planning procedure is a valuable tool for clinical and experimental use and evaluation of electroporation-based treatments.

  4. Secondary Organic Aerosol Formation from Glyoxal: photochemical versus dark uptake and reversible versus irreversible SOA formation

    Science.gov (United States)

    Waxman, E.; Slowik, J.; Kampf, C.; Timkovsky, J.; Noziere, B.; Praplan, A.; Pffafenberger, L.; Holzinger, R.; Hoffmann, T.; Dommen, J.; Prevot, A.; Baltensperger, U.; Volkamer, R.

    2012-04-01

    Glyoxal forms secondary organic aerosol (SOA) by partitioning to the aerosol aqueous phase according to Henry's law. The subsequent processing by heterogeneous and multiphase reactions shifts the partitioning towards aerosols. Currently it is not well understood whether these reactions result in reversible or irreversible SOA formation, and what parameters influence the rate limiting step of multiphase processing. We conducted a series of simulation chamber experiments at PSI in April and May 2011 to investigate processing under dark conditions, UV and/or visible light irradiated conditions, and in the presence and absence of OH radicals. Experiments used ammonium sulfate or ammonium sulfate/fulvic acid mixtures as seed aerosols, and were conducted between 50% and 85% relative humidity at approximately constant RH over the course of any given experiment. Glyoxal was produced photochemically from acetylene, using HONO photolysis as the OH radical source. Gas-phase glyoxal was measured by the CU LED-Cavity Enhanced-DOAS. The Thermal-Desorption Proton-Transfer-Reaction Mass Spectrometer (TD-PTR-MS) and Ion Chromatography Mass Spectrometer (IC-MS) monitored both gas and aerosol-phase organic reaction products. Particle composition was monitored by High-Resolution Time-of-Flight Aerosol Mass Spectrometry (HR-ToF-AMS), and HPLC-ESI MS/MS and LC-MS analysis of filter samples.

  5. New fully superconducting bearing concept using the difference in irreversibility field of two superconducting components

    Energy Technology Data Exchange (ETDEWEB)

    Patel, A; Glowacki, B A [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Palka, R, E-mail: ap604@cam.ac.u [Department of Power Systems and Electrical Drives, West Pomeranian University of Technology, ulica Sikorskiego 37, 70-313 Szczecin (Poland)

    2011-01-15

    One of the major factors limiting levitation force for existing superconducting magnetic bearings is the maximum possible remanence of 1.4 T known to exist for rare-earth permanent magnets. This paper introduces the novel concept of a magnetic bearing which uses the difference in irreversibility field of two superconducting components to allow one component to be field cooled in the field originating from the other component which is first magnetized at a higher temperature. Magnetized (RE)BCO bulks with high trapped fields can be used as one of the components instead of permanent magnets, giving a significant increase in the levitation force density that can be achieved between the two components. This paper focuses on using an MgB{sub 2} hollow cylinder for the component which is field cooled. Modelling of the levitation forces that would exist between magnetized YBCO bulks inside a hollow MgB{sub 2} cylinder is reported as well as modelling of pulsed field magnetization of the pellets to create high field gradients using MPSC (multi-pulse technique with step-wise cooling). The new design has the potential to achieve levitation force densities over 100 N cm{sup -2}.

  6. Long-term experiments to investigate irreversibility in sorption of pesticides to soil.

    Science.gov (United States)

    Suddaby, L A; Beulke, S; van Beinum, W; Oliver, R G; Kuet, S; Brown, C D

    2016-11-01

    Experiments investigated irreversibility in pesticide sorption to soil. Sorption behaviour under abiotic conditions was quantified for chlorotoluron, prometryn and hexaconazole in three soils over periods of up to 274 days. An isotope-exchange procedure was used whereby sorption of (12)C- and (14)C-pesticide isotopes in shaken suspensions of three soils (56-168 days shaking) was followed by substitution of the isotopes in the liquid phase and a 14-day exchange phase. This was followed by forced isotope exchange where the sorbed (14)C material was exchanged by adding an excess of non-radiolabelled compound. Experiments were concluded with solvent extraction and soil combustion to determine remaining radioactivity. Under conditions of continuous shaking, the pesticide-soil systems took around four months to approach sorption equilibrium, resulting in strong asymmetry between the profiles of exchange for isotopes of all three compounds. Physically entrapped residues were released back into solution under the steep concentration gradient of forced isotope exchange and small amounts of radioactivity were still being released at the termination of the experiment. The profiles of exchange did not deviate markedly from ideal behaviour based on the assumption that sorption is fully reversible. Whilst the timescales for release of sorbed residues back into solution were very long, soil combustion at study termination only yielded <1-2% of applied radioactivity; this confirms that sorption processes under abiotic soil conditions were overwhelmingly reversible for this set of compounds and soils. PMID:27479454

  7. Vertical distribution of overpotentials and irreversible charge losses in lithium ion battery electrodes.

    Science.gov (United States)

    Klink, Stefan; Schuhmann, Wolfgang; La Mantia, Fabio

    2014-08-01

    Porous lithium ion battery electrodes are characterized using a vertical distribution of cross-currents. In an appropriate simplification, this distribution can be described by a transmission line model (TLM) consisting of infinitely thin electrode layers. To investigate the vertical distribution of currents, overpotentials, and irreversible charge losses in a porous graphite electrode in situ, a multi-layered working electrode (MWE) was developed as the experimental analogue of a TLM. In this MWE, each layer is in ionic contact but electrically insulated from the other layers by a porous separator. It was found that the negative graphite electrodes get lithiated and delithiated stage-by-stage and layer-by-layer. Several mass-transport- as well as non-mass-transport-limited processes could be identified. Local current densities can reach double the average, especially on the outermost layer at the beginning of each intercalation stage. Furthermore, graphite particles close to the counter electrode act as "electrochemical sieve" reducing the impurities present in the electrolyte such as water.

  8. Irreversible bonding of polyimide and polydimethylsiloxane (PDMS) based on a thiol-epoxy click reaction

    Science.gov (United States)

    Hoang, Michelle V.; Chung, Hyun-Joong; Elias, Anastasia L.

    2016-10-01

    Polyimide is one of the most popular substrate materials for the microfabrication of flexible electronics, while polydimethylsiloxane (PDMS) is the most widely used stretchable substrate/encapsulant material. These two polymers are essential in fabricating devices for microfluidics, bioelectronics, and the internet of things; bonding these materials together is a crucial challenge. In this work, we employ click chemistry at room temperature to irreversibly bond polyimide and PDMS through thiol-epoxy bonds using two different methods. In the first method, we functionalize the surfaces of the PDMS and polyimide substrates with mercaptosilanes and epoxysilanes, respectively, for the formation of a thiol-epoxy bond in the click reaction. In the second method, we functionalize one or both surfaces with mercaptosilane and introduce an epoxy adhesive layer between the two surfaces. When the surfaces are bonded using the epoxy adhesive without any surface functionalization, an extremely small peel strength (0.3 N mm-1 (method 2) are observed, and failure occurs by tearing of the PDMS layer. We envision that the novel processing route employing click chemistry can be utilized in various cases of stretchable and flexible device fabrication.

  9. Irreversible thermodynamics of open chemical networks. I. Emergent cycles and broken conservation laws.

    Science.gov (United States)

    Polettini, Matteo; Esposito, Massimiliano

    2014-07-14

    In this paper and Paper II, we outline a general framework for the thermodynamic description of open chemical reaction networks, with special regard to metabolic networks regulating cellular physiology and biochemical functions. We first introduce closed networks "in a box", whose thermodynamics is subjected to strict physical constraints: the mass-action law, elementarity of processes, and detailed balance. We further digress on the role of solvents and on the seemingly unacknowledged property of network independence of free energy landscapes. We then open the system by assuming that the concentrations of certain substrate species (the chemostats) are fixed, whether because promptly regulated by the environment via contact with reservoirs, or because nearly constant in a time window. As a result, the system is driven out of equilibrium. A rich algebraic and topological structure ensues in the network of internal species: Emergent irreversible cycles are associated with nonvanishing affinities, whose symmetries are dictated by the breakage of conservation laws. These central results are resumed in the relation a + b = s(Y) between the number of fundamental affinities a, that of broken conservation laws b and the number of chemostats s(Y). We decompose the steady state entropy production rate in terms of fundamental fluxes and affinities in the spirit of Schnakenberg's theory of network thermodynamics, paving the way for the forthcoming treatment of the linear regime, of efficiency and tight coupling, of free energy transduction, and of thermodynamic constraints for network reconstruction. PMID:25028009

  10. The role of beaded activated carbon's surface oxygen groups on irreversible adsorption of organic vapors.

    Science.gov (United States)

    Jahandar Lashaki, Masoud; Atkinson, John D; Hashisho, Zaher; Phillips, John H; Anderson, James E; Nichols, Mark

    2016-11-01

    The objective of this study is to determine the contribution of surface oxygen groups to irreversible adsorption (aka heel formation) during cyclic adsorption/regeneration of organic vapors commonly found in industrial systems, including vehicle-painting operations. For this purpose, three chemically modified activated carbon samples, including two oxygen-deficient (hydrogen-treated and heat-treated) and one oxygen-rich sample (nitric acid-treated) were prepared. The samples were tested for 5 adsorption/regeneration cycles using a mixture of nine organic compounds. For the different samples, mass balance cumulative heel was 14 and 20% higher for oxygen functionalized and hydrogen-treated samples, respectively, relative to heat-treated sample. Thermal analysis results showed heel formation due to physisorption for the oxygen-deficient samples, and weakened physisorption combined with chemisorption for the oxygen-rich sample. Chemisorption was attributed to consumption of surface oxygen groups by adsorbed species, resulting in formation of high boiling point oxidation byproducts or bonding between the adsorbates and the surface groups. Pore size distributions indicated that different pore sizes contributed to heel formation - narrow micropores (<7Å) in the oxygen-deficient samples and midsize micropores (7-12Å) in the oxygen-rich sample. The results from this study help explain the heel formation mechanism and how it relates to chemically tailored adsorbent materials. PMID:27295065

  11. Irreversible electroporation and the pancreas: What we know and where we are going?

    Science.gov (United States)

    Young, Shamar J

    2015-08-27

    Pancreatic adenocarcinoma continues to have a poor prognosis with 1 and 5 years survival rates of 27% and 6% respectively. The gold standard of treatment is resection, however, only approximately 10% of patients present with resectable disease. Approximately 40% of patients present with disease that is too locally advanced to resect. There is great interest in improving outcomes in this patient population and ablation techniques have been investigated as a potential solution. Unfortunately early investigations into thermal ablation techniques, particularly radiofrequency ablation, resulted in unacceptably high morbidity rates. Irreversible electroporation (IRE) has been introduced and is promising as it does not rely on thermal energy and has shown an ability to leave structural cells such as blood vessels and bile ducts intact during animal studies. IRE also does not suffer from heat sink effect, a concern given the large number of blood vessels surrounding the pancreas. IRE showed significant promise during preclinical animal trials and as such has moved on to clinical testing. There are as of yet only a few studies which look at the applications of IRE within humans in the setting of pancreatic adenocarcinoma. This paper reviews the basic principles, techniques, and current clinical data available on IRE.

  12. Bacterial, fungal and yeast contamination in six brands of irreversible hydrocolloid impression materials.

    Science.gov (United States)

    Casemiro, Luciana Assirati; Martins, Carlos Henrique Gomes; de Souza, Fernanda de Carvalho Panzeri Pires; Panzeri, Heitor; Ito, Isabel Yoko

    2007-01-01

    This study assessed the level of contamination of six commercially available irreversible hydrocolloids (two containing chlorhexidine) and identified the contamination present in the materials. Petri dishes containing selective and enriched culture media were inoculated with alginate powder (0.06 g), in triplicate. After incubation (37 degrees C/7 days), the colony-forming units (CFU) were counted and Gram stained. Biochemical identification of the different morphotypes was also performed. The contamination levels for the materials were: Jeltrate--389 CFU/g; Jeltrate Plus--516 CFU/g; Jeltrate Chromatic--135 CFU/g; Hydrogum--1,455 CFU/g; Kromopan--840 CFU/g; and Greengel--59 CFU/g. Gram staining revealed the presence of Gram-positive bacillus and Gram-positive cocci. The bacteria Staphylococcus epidermidis, Bacillus subtilis, Bacillus sp., Bacillus coagulans, Bacillus licheniformis, Bacillus cereus, Micrococcus luteus, and Nocardia sp.; the filamentous fungi Aspergillus niger, Aspergillus flavus, Rhizopus sp., Neurospora sp.; and the yeast Candida sp. were isolated. The contamination detected in the impression materials points out the need for adopting measures to improve the microbiological quality of these materials. The use of contaminated materials in the oral cavity goes against the basic principles for controlling cross-contamination and may represent a risk for debilitated or immunocompromised patients.

  13. Parametric optimum analysis of an irreversible Ericsson cryogenic refrigeration cycle working with an ideal Fermi gas

    Indian Academy of Sciences (India)

    Bihong Lin; Yingru Zhao; Jincan Chen

    2008-05-01

    An irreversible model of an Ericsson cryogenic refrigeration cycle working with an ideal Fermi gas is established, which is composed of two isothermal and two isobaric processes. The influence of both the quantum degeneracy and the finite-rate heat transfer between the working fluid and the heat reservoirs on the performance of the cycle is investigated, based on the theory of statistical mechanics and thermodynamic properties of an ideal Fermi gas. The inherent regeneration losses of the cycle are analyzed. Expressions for several important performance parameters such as the coefficient of performance, cooling rate and power input are derived. By using numerical solutions, the cooling rate of the cycle is optimized for a given power input. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal regions of the coefficient of performance and power input are determined. Especially, the optimal performance of the cycle in the strong and weak gas degeneracy cases and the high temperature limit is discussed in detail. The analytic expressions of some optimized parameters are derived. Some optimum criteria are given. The distinctions and connections between the Ericsson refrigeration cycles working with the Fermi and classical gases are revealed.

  14. Irreversible muscle damage in bodybuilding due to long-term intramuscular oil injection.

    Science.gov (United States)

    Banke, I J; Prodinger, P M; Waldt, S; Weirich, G; Holzapfel, B M; Gradinger, R; Rechl, H

    2012-10-01

    Intramuscular oil injections generating slowly degrading oil-based depots represent a controversial subject in bodybuilding and fitness. However they seem to be commonly reported in a large number of non-medical reports, movies and application protocols for 'site-injections'. Surprisingly the impact of long-term (ab)use on the musculature as well as potential side-effects compromising health and sports ability are lacking in the medical literature. We present the case of a 40 year old male semi-professional bodybuilder with systemic infection and painful reddened swellings of the right upper arm forcing him to discontinue weightlifting. Over the last 8 years he daily self-injected sterilized sesame seed oil at numerous intramuscular locations for the purpose of massive muscle building. Whole body MRI showed more than 100 intramuscular rather than subcutaneous oil cysts and loss of normal muscle anatomy. 2-step septic surgery of the right upper arm revealed pus-filled cystic scar tissue with the near-complete absence of normal muscle. MRI 1 year later revealed the absence of relevant muscle regeneration. Persistent pain and inability to perform normal weight training were evident for at least 3 years post-surgery. This alarming finding indicating irreversible muscle mutilation may hopefully discourage people interested in bodybuilding and fitness from oil-injections. The impact of such chronic tissue stress on other diseases like malignancy remains to be determined.

  15. The feasibility of using irreversible electroporation to introduce pores in bacterial cellulose scaffolds for tissue engineering.

    Science.gov (United States)

    Baah-Dwomoh, Adwoa; Rolong, Andrea; Gatenholm, Paul; Davalos, Rafael V

    2015-06-01

    This work investigates the feasibility of the use of irreversible electroporation (IRE) in the biofabrication of 3D cellulose nanofibril networks via the bacterial strain Gluconacetobacter xylinus. IRE uses electrical pulses to increase membrane permeability by altering the transmembrane potential; past a threshold, damage to the cell becomes too great and leads to cell death. We hypothesized that using IRE to kill the bacteria at specific locations and particular times, we could introduce conduits in the overall scaffold by preventing cellulose biosynthesis locally. Through mathematical modeling and experimental techniques, electrical effects were investigated and the parameters for IRE of G. xylinus were determined. We found that for a specific set of parameters, an applied electric field of 8 to 12.5 kV/cm, producing a local field of 3 kV/cm, was sufficient to kill most of the bacteria and create a localized pore. However, an applied electric field of 17.5 kV/cm was required to kill all. Results suggest that IRE may be an effective tool to create scaffolds with appropriate porosity for orthopedic applications. Ideally, these engineered scaffolds could be used to successfully treat osteochondral defects.

  16. Irreversible Wash Aid Additive for Cesium Mitigation. Small-Scale Demonstration and Lessons Learned

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, Michael [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-01-01

    The Irreversible Wash Aid Additive process has been under development by the U.S. Environmental Protection Agency (EPA) and Argonne National Laboratory (Argonne). This process for radioactive cesium mitigation consists of a solution to wash down contaminated structures, roadways, and vehicles and a sequestering agent to bind the radionuclides from the wash water and render them environmentally immobile. The purpose of this process is to restore functionality to basic services and immediately reduce the consequences of a radiologically-contaminated urban environment. Research and development have resulted in a down-selection of technologies for integration and demonstration at the pilot-scale level as part of the Wide Area Recovery and Resiliency Program (WARRP) under the Department of Homeland Security and the Denver Urban Area Security Initiative. As part of developing the methods for performing a pilot-scale demonstration at the WARRP conference in Denver in 2012, Argonne conducted small-scale field experiments at Separmatic Systems. The main purpose of these experiments was to refine the wash water collection and separations systems and demonstrate key unit operations to help in planning for the large scale demonstration in Denver. Since the purpose of these tests was to demonstrate the operations of the system, we used no radioactive materials. After a brief set of experiments with the LAKOS unit to familiarize ourselves with its operation, two experiments were completed on two separate dates with the Separmatic systems.

  17. Irreversible muscle damage in bodybuilding due to long-term intramuscular oil injection.

    Science.gov (United States)

    Banke, I J; Prodinger, P M; Waldt, S; Weirich, G; Holzapfel, B M; Gradinger, R; Rechl, H

    2012-10-01

    Intramuscular oil injections generating slowly degrading oil-based depots represent a controversial subject in bodybuilding and fitness. However they seem to be commonly reported in a large number of non-medical reports, movies and application protocols for 'site-injections'. Surprisingly the impact of long-term (ab)use on the musculature as well as potential side-effects compromising health and sports ability are lacking in the medical literature. We present the case of a 40 year old male semi-professional bodybuilder with systemic infection and painful reddened swellings of the right upper arm forcing him to discontinue weightlifting. Over the last 8 years he daily self-injected sterilized sesame seed oil at numerous intramuscular locations for the purpose of massive muscle building. Whole body MRI showed more than 100 intramuscular rather than subcutaneous oil cysts and loss of normal muscle anatomy. 2-step septic surgery of the right upper arm revealed pus-filled cystic scar tissue with the near-complete absence of normal muscle. MRI 1 year later revealed the absence of relevant muscle regeneration. Persistent pain and inability to perform normal weight training were evident for at least 3 years post-surgery. This alarming finding indicating irreversible muscle mutilation may hopefully discourage people interested in bodybuilding and fitness from oil-injections. The impact of such chronic tissue stress on other diseases like malignancy remains to be determined. PMID:22592548

  18. New fully superconducting bearing concept using the difference in irreversibility field of two superconducting components

    Science.gov (United States)

    Patel, A.; Palka, R.; Glowacki, B. A.

    2011-01-01

    One of the major factors limiting levitation force for existing superconducting magnetic bearings is the maximum possible remanence of 1.4 T known to exist for rare-earth permanent magnets. This paper introduces the novel concept of a magnetic bearing which uses the difference in irreversibility field of two superconducting components to allow one component to be field cooled in the field originating from the other component which is first magnetized at a higher temperature. Magnetized (RE)BCO bulks with high trapped fields can be used as one of the components instead of permanent magnets, giving a significant increase in the levitation force density that can be achieved between the two components. This paper focuses on using an MgB2 hollow cylinder for the component which is field cooled. Modelling of the levitation forces that would exist between magnetized YBCO bulks inside a hollow MgB2 cylinder is reported as well as modelling of pulsed field magnetization of the pellets to create high field gradients using MPSC (multi-pulse technique with step-wise cooling). The new design has the potential to achieve levitation force densities over 100 N cm - 2.

  19. Traffic time series analysis by using multiscale time irreversibility and entropy

    Science.gov (United States)

    Wang, Xuejiao; Shang, Pengjian; Fang, Jintang

    2014-09-01

    Traffic systems, especially urban traffic systems, are regulated by different kinds of interacting mechanisms which operate across multiple spatial and temporal scales. Traditional approaches fail to account for the multiple time scales inherent in time series, such as empirical probability distribution function and detrended fluctuation analysis, which have lead to different results. The role of multiscale analytical method in traffic time series is a frontier area of investigation. In this paper, our main purpose is to introduce a new method—multiscale time irreversibility, which is helpful to extract information from traffic time series we studied. In addition, to analyse the complexity of traffic volume time series of Beijing Ring 2, 3, 4 roads between workdays and weekends, which are from August 18, 2012 to October 26, 2012, we also compare the results by this new method and multiscale entropy method we have known well. The results show that the higher asymmetry index we get, the higher traffic congestion level will be, and accord with those which are obtained by multiscale entropy.

  20. Pretreatment with alum or powdered activated carbon reduces bacterial predation-associated irreversible fouling of membranes.

    Science.gov (United States)

    Kim, Eun-Ho; Dwidar, Mohammed; Kwon, Young-Nam; Mitchell, Robert J

    2014-01-01

    This study evaluated the co-application of bacterial predation by Bdellovibrio bacteriovorus and either alum coagulation or powdered activated carbon adsorption to reduce fouling caused by Escherichia coli rich feed solutions in dead-end microfiltration tests. The flux increased when the samples were predated upon or treated with 100 ppm alum or PAC, but co-treatment with alum and predation gave the best flux results. The total membrane resistance caused by the predated sample was reduced six-fold when treated with 100 ppm PAC, from 11.8 to 1.98 × 10(11) m(-1), while irreversible fouling (Rp) was 2.7-fold lower. Treatment with 100 ppm alum reduced the total resistance 14.9-fold (11.8 to 0.79 × 10(11) m(-1)) while the Rp decreased 4.25-fold. SEM imaging confirmed this, with less obvious fouling of the membrane after the combined process. This study illustrates that the combination of bacterial predation and the subsequent removal of debris using coagulation or adsorption mitigates membrane biofouling and improves membrane performance. PMID:25410737

  1. Irreversible membrane fouling abatement through pre-deposited layer of hierarchical porous carbons.

    Science.gov (United States)

    Hamad, Juma Z; Dua, Rubal; Kurniasari, Novita; Kennedy, Maria D; Wang, Peng; Amy, Gary L

    2014-11-15

    In this work, dual-templated hierarchical porous carbons (HPCs), produced from a coupled ice-hard templating approach, are shown to be a highly effective solution to the commonly occurring problem of irreversible fouling of low-pressure membranes used for pre-treatment in wastewater reuse. For the first time, dual-templated HPCs, along with their respective counterparts - single-templated meso-porous carbon (MPCs) (without macropores) - are tested in terms of their fouling reduction capacity and ability to remove different effluent organic matter fractions present in wastewater and compared with a commercially available powdered activated carbon (PAC). The synthesized HPCs provided exceptional fouling abatement, a 4-fold higher fouling reduction as compared to the previously reported best performing commercial PAC and ∼2.5-fold better fouling reduction than their respective mesoporous counterpart. Thus, it is shown that not only mesoporosity, but macroporosity is also necessary to achieve high fouling reduction, thus emphasizing the need for dual templating. In the case of HPCs, the pre-deposition technique is also found to outperform the traditional sorbent-feed mixing approach, mainly in terms of removal of fouling components. Based on their superior performance, a high permeability (ultra-low-pressure) membrane consisting of the synthesized HPC pre-deposited on a large pore size membrane support (0.45 μm membrane), is shown to give excellent pre-treatment performance for wastewater reuse application. PMID:25128660

  2. Irreversible membrane fouling abatement through pre-deposited layer of hierarchical porous carbons

    KAUST Repository

    Hamad, Juma

    2014-11-01

    In this work, dual-templated hierarchical porous carbons (HPCs), produced from a coupled ice-hard templating approach, are shown to be a highly effective solution to the commonly occurring problem of irreversible fouling of low-pressure membranes used for pre-treatment in wastewater reuse. For the first time, dual-templated HPCs, along with their respective counterparts - single-templated meso-porous carbon (MPCs) (without macropores) - are tested in terms of their fouling reduction capacity and ability to remove different effluent organic matter fractions present in wastewater and compared with a commercially available powdered activated carbon (PAC). The synthesized HPCs provided exceptional fouling abatement, a 4-fold higher fouling reduction as compared to the previously reported best performing commercial PAC and ~2.5-fold better fouling reduction than their respective mesoporous counterpart. Thus, it is shown that not only mesoporosity, but macroporosity is also necessary to achieve high fouling reduction, thus emphasizing the need for dual templating. In the case of HPCs, the pre-deposition technique is also found to outperform the traditional sorbent-feed mixing approach, mainly in terms of removal of fouling components. Based on their superior performance, a high permeability (ultra-low-pressure) membrane consisting of the synthesized HPC pre-deposited on a large pore size membrane support (0.45μm membrane), is shown to give excellent pre-treatment performance for wastewater reuse application. © 2014 Elsevier Ltd.

  3. Detection of irreversible changes in susceptibility-weighted images after whole-brain irradiation of children

    Energy Technology Data Exchange (ETDEWEB)

    Peters, S.; Jansen, O. [University of Schleswig-Holstein, Institute of Neuroradiology, Kiel (Germany); Pahl, R. [University of Schleswig-Holstein, Clinic for Radiooncology, Kiel (Germany); Claviez, A. [University of Schleswig-Holstein, Clinic for Paediatrics, Kiel (Germany)

    2013-07-15

    Whole-brain irradiation is part of the therapy protocol for patients with medulloblastomas. Side effects and complications of radiation can be detected by follow-up magnetic resonance imaging (MRI). Susceptibility-weighted images (SWI) can detect even very small amounts of residual blood that cannot be shown with conventional MRI. The purpose of this study was to determine when and where SWI lesions appear after whole-brain irradiation. MRI follow-up of seven patients with medulloblastoma who were treated with whole-brain irradiation were analyzed retrospectively. SWI were part of the initial and follow-up MRI protocol. De novo SWI lesions, localization, and development over time were documented. At time of irradiation, mean age of the patients was 13 years ({+-}4 years). Earliest SWI lesions were detected 4 months after radiation treatment. In all patients, SWI lesions accumulated over time, although the individual number of SWI lesions varied. No specific dissemination of SWI lesions was observed. Whole-brain irradiation can cause relatively early dot-like SWI lesions. The lesions are irreversible and accumulate over time. Histopathological correlation and clinical impact of these SWI lesions should be investigated. (orig.)

  4. Local equilibrium and the second law of thermodynamics for irreversible systems with thermodynamic inertia

    International Nuclear Information System (INIS)

    Validity of local equilibrium has been questioned for non-equilibrium systems which are characterized by delayed response. In particular, for systems with non-zero thermodynamic inertia, the assumption of local equilibrium leads to negative values of the entropy production, which is in contradiction with the second law of thermodynamics. In this paper, we address this question by suggesting a variational formulation of irreversible evolution of a system with non-zero thermodynamic inertia. We introduce the Lagrangian, which depends on the properties of the normal and the so-called “mirror-image” systems. We show that the standard evolution equations, in particular, the Maxwell-Cattaneo-Vernotte equation, can be derived from the variational procedure without going beyond the assumption of local equilibrium. We also argue that the second law of thermodynamics in non-equilibrium should be understood as a consequence of the variational procedure and the property of local equilibrium. For systems with instantaneous response this leads to the standard requirement of the local instantaneous entropy production being always positive. However, if a system is characterized by delayed response, the formulation of the second law of thermodynamics should be altered. In particular, the quantity, which is always positive, is not the instantaneous entropy production, but the entropy production averaged over a proper time interval

  5. Observation of irreversible current path in polymer dielectric using conductive atomic force microscope

    Science.gov (United States)

    Jung, Ji-Hoon; Kim, Woo Young; Kim, Do-Kyung; Kwon, Jin-Hyuk; Lee, Hee Chul; Bae, Jin-Hyuk

    2015-03-01

    During the measurement of the electrical properties of a metal-polymer-metal capacitor, it was found that the capacitor exhibited write-once-read-many-times (WORM) memory behavior, even though it was made of the dielectric polymer, polystyrene. The initial low conductance state changed to a high conductance state when a threshold voltage was applied, but this final state never reverted to the initial state. This phenomenon only appeared in sub-100-nm-thick films. To understand this phenomenon, conductive atomic force microscopy (CAFM) was used. The current distribution measured with CAFM showed an irreversible current path had formed near particles in the polymer film. For reproducibility, particles were intentionally inserted into the polymer film during the fabrication of metal-polymer-metal capacitors, and the same current mechanism was found. From these results, it is concluded that the purification and cleaning process of organic devices severely affects the device characteristics. In addition, particle-insertion appears to be a promising method for fabrication low-cost and air-stable WORM type memory for various applications. [Figure not available: see fulltext.

  6. Irreversible Wash Aid Additive for Cesium Mitigation. Small-Scale Demonstration and Lessons Learned

    International Nuclear Information System (INIS)

    The Irreversible Wash Aid Additive process has been under development by the U.S. Environmental Protection Agency (EPA) and Argonne National Laboratory (Argonne). This process for radioactive cesium mitigation consists of a solution to wash down contaminated structures, roadways, and vehicles and a sequestering agent to bind the radionuclides from the wash water and render them environmentally immobile. The purpose of this process is to restore functionality to basic services and immediately reduce the consequences of a radiologically-contaminated urban environment. Research and development have resulted in a down-selection of technologies for integration and demonstration at the pilot-scale level as part of the Wide Area Recovery and Resiliency Program (WARRP) under the Department of Homeland Security and the Denver Urban Area Security Initiative. As part of developing the methods for performing a pilot-scale demonstration at the WARRP conference in Denver in 2012, Argonne conducted small-scale field experiments at Separmatic Systems. The main purpose of these experiments was to refine the wash water collection and separations systems and demonstrate key unit operations to help in planning for the large scale demonstration in Denver. Since the purpose of these tests was to demonstrate the operations of the system, we used no radioactive materials. After a brief set of experiments with the LAKOS unit to familiarize ourselves with its operation, two experiments were completed on two separate dates with the Separmatic systems.

  7. Irreversible adsorption of atmospheric helium on olivine: A lobster pot analogy

    Science.gov (United States)

    Protin, Marie; Blard, Pierre-Henri; Marrocchi, Yves; Mathon, François

    2016-04-01

    This study reports new experimental results that demonstrate that large amounts of atmospheric helium may be adsorbed onto the surfaces of olivine grains. This behavior is surface-area-related in that this contamination preferentially affects grains that are smaller than 125 μm in size. One of the most striking results of our study is that in vacuo heating at 900 °C for 15 min is not sufficient to completely remove the atmospheric contamination. This suggests that the adsorption of helium may involve high-energy trapping of helium through irreversible anomalous adsorption. This trapping process of helium can thus be compared to a "lobster pot" adsorption: atmospheric helium easily gets in, but hardly gets out. While this type of behavior has previously been reported for heavy noble gases (Ar, Kr, Xe), this is the first time that it has been observed for helium. Adsorption of helium has, until now, generally been considered to be negligible on silicate surfaces. Our findings have significant implications for helium and noble gas analysis of natural silicate samples, such as for cosmic-ray exposure dating or noble gas characterization of extraterrestrial material. Analytical procedures in future studies should be adapted in order to avoid this contamination. The results of this study also allow us to propose an alternative explanation for previously described matrix loss of cosmogenic 3He.

  8. Local equilibrium and the second law of thermodynamics for irreversible systems with thermodynamic inertia

    Energy Technology Data Exchange (ETDEWEB)

    Glavatskiy, K. S. [School of Chemical Engineering, The University of Queensland, St. Lucia QLD 4072 (Australia)

    2015-10-28

    Validity of local equilibrium has been questioned for non-equilibrium systems which are characterized by delayed response. In particular, for systems with non-zero thermodynamic inertia, the assumption of local equilibrium leads to negative values of the entropy production, which is in contradiction with the second law of thermodynamics. In this paper, we address this question by suggesting a variational formulation of irreversible evolution of a system with non-zero thermodynamic inertia. We introduce the Lagrangian, which depends on the properties of the normal and the so-called “mirror-image” systems. We show that the standard evolution equations, in particular, the Maxwell-Cattaneo-Vernotte equation, can be derived from the variational procedure without going beyond the assumption of local equilibrium. We also argue that the second law of thermodynamics in non-equilibrium should be understood as a consequence of the variational procedure and the property of local equilibrium. For systems with instantaneous response this leads to the standard requirement of the local instantaneous entropy production being always positive. However, if a system is characterized by delayed response, the formulation of the second law of thermodynamics should be altered. In particular, the quantity, which is always positive, is not the instantaneous entropy production, but the entropy production averaged over a proper time interval.

  9. Enzymatic treatment for controlling irreversible membrane fouling in cross-flow humic acid-fed ultrafiltration

    International Nuclear Information System (INIS)

    Exploring reasonable ways to remove foulant is of great importance in order to allow sustainable operation of ultrafiltration (UF) membranes in water/wastewater treatment technology. Compounds of organic and inorganic origin largely contribute to irreversible fouling. This study attempted to remove problem of UF membrane fouling by using four different enzymes including α-amylase, lipase, cellulase and protease. This investigation showed that none of the above mentioned enzymes was found to be effective for the removal of foulant when used alone. However, when these enzymes were used in combination with NaOH and citric acid, about 90% cleaning was achieved. The addition of non-ionic surfactant to the enzymatic solution appears to increase the efficiency of flux recovery by reducing the adhesion of foulant species to the membrane surface through the decrease of contact angle. Field emission gun scanning electron microscopy, Fourier transform infrared spectroscopy and atomic force microscopy (AFM) techniques were employed to qualitatively illustrate the foulant characteristics. The surface roughness through AFM was used to explain the potential mechanism for the enzymatic cleaning.

  10. Irreversible and reversible reactive chromatography: analytical solutions and moment analysis for rectangular pulse injections.

    Science.gov (United States)

    Bibi, Sameena; Qamar, Shamsul; Seidel-Morgenstern, Andreas

    2015-03-13

    This work is concerned with the analysis of models for linear reactive chromatography describing irreversible A→B and reversible A↔B reactions. In contrast to previously published results rectangular reactant pulses are injected into initially empty or pre-equilibrated columns assuming both Dirichlet and Danckwerts boundary conditions. The models consist of two partial differential equations, accounting for convection, longitudinal dispersion and first order chemical reactions. Due to the effect of involved mechanisms on solute transport, analytical and numerical solutions of the models could be helpful to understand, design and optimize chromatographic reactors. The Laplace transformation is applied to solve the model equations analytically for linear adsorption isotherms. Statistical temporal moments are derived from solutions in the Laplace domain. Analytical results are compared with numerical predictions generated using a high-resolution finite volume scheme for two sets of boundary conditions. Several case studies are carried out to analyze reactive liquid chromatographic processes for a wide range of mass transfer and reaction kinetics. Good agreements in the results validate the correctness of the analytical solutions and accuracy of the proposed numerical algorithm. PMID:25670415

  11. Magnetization of underdoped YBa2Cu3Oy above the irreversibility field

    Science.gov (United States)

    Yu, Jing Fei; Ramshaw, B. J.; Kokanović, I.; Modic, K. A.; Harrison, N.; Day, James; Liang, Ruixing; Hardy, W. N.; Bonn, D. A.; McCollam, A.; Julian, S. R.; Cooper, J. R.

    2015-11-01

    Torque magnetization measurements on YBa2Cu3Oy (YBCO) at doping y =6.67 (p =0.12 ), in dc fields (B ) up to 33 T and temperatures down to 4.5 K, show that weak diamagnetism persists above the extrapolated irreversibility field Hirr(T =0 ) ≈24 T. The differential susceptibility d M /d B , however, is more rapidly suppressed for B ≳16 T than expected from the properties of the low field superconducting state, and saturates at a low value for fields B ≳24 T. In addition, torque measurements on a p =0.11 YBCO crystal in pulsed field up to 65 T and temperatures down to 8 K show similar behavior, with no additional features at higher fields. We offer two candidate scenarios to explain these observations: (a) superconductivity survives but is heavily suppressed at high field by competition with charge-density-wave (CDW) order; (b) static superconductivity disappears near 24 T and is followed by a region of fluctuating superconductivity, which causes d M /d B to saturate at high field. The diamagnetic signal observed above 50 T for the p =0.11 crystal at 40 K and below may be caused by changes in the normal state susceptibility rather than bulk or fluctuating superconductivity. There will be orbital (Landau) diamagnetism from electron pockets and possibly a reduction in spin susceptibility caused by the stronger three-dimensional ordered CDW.

  12. New fully superconducting bearing concept using the difference in irreversibility field of two superconducting components

    International Nuclear Information System (INIS)

    One of the major factors limiting levitation force for existing superconducting magnetic bearings is the maximum possible remanence of 1.4 T known to exist for rare-earth permanent magnets. This paper introduces the novel concept of a magnetic bearing which uses the difference in irreversibility field of two superconducting components to allow one component to be field cooled in the field originating from the other component which is first magnetized at a higher temperature. Magnetized (RE)BCO bulks with high trapped fields can be used as one of the components instead of permanent magnets, giving a significant increase in the levitation force density that can be achieved between the two components. This paper focuses on using an MgB2 hollow cylinder for the component which is field cooled. Modelling of the levitation forces that would exist between magnetized YBCO bulks inside a hollow MgB2 cylinder is reported as well as modelling of pulsed field magnetization of the pellets to create high field gradients using MPSC (multi-pulse technique with step-wise cooling). The new design has the potential to achieve levitation force densities over 100 N cm-2.

  13. Bacterial, fungal and yeast contamination in six brands of irreversible hydrocolloid impression materials.

    Science.gov (United States)

    Casemiro, Luciana Assirati; Martins, Carlos Henrique Gomes; de Souza, Fernanda de Carvalho Panzeri Pires; Panzeri, Heitor; Ito, Isabel Yoko

    2007-01-01

    This study assessed the level of contamination of six commercially available irreversible hydrocolloids (two containing chlorhexidine) and identified the contamination present in the materials. Petri dishes containing selective and enriched culture media were inoculated with alginate powder (0.06 g), in triplicate. After incubation (37 degrees C/7 days), the colony-forming units (CFU) were counted and Gram stained. Biochemical identification of the different morphotypes was also performed. The contamination levels for the materials were: Jeltrate--389 CFU/g; Jeltrate Plus--516 CFU/g; Jeltrate Chromatic--135 CFU/g; Hydrogum--1,455 CFU/g; Kromopan--840 CFU/g; and Greengel--59 CFU/g. Gram staining revealed the presence of Gram-positive bacillus and Gram-positive cocci. The bacteria Staphylococcus epidermidis, Bacillus subtilis, Bacillus sp., Bacillus coagulans, Bacillus licheniformis, Bacillus cereus, Micrococcus luteus, and Nocardia sp.; the filamentous fungi Aspergillus niger, Aspergillus flavus, Rhizopus sp., Neurospora sp.; and the yeast Candida sp. were isolated. The contamination detected in the impression materials points out the need for adopting measures to improve the microbiological quality of these materials. The use of contaminated materials in the oral cavity goes against the basic principles for controlling cross-contamination and may represent a risk for debilitated or immunocompromised patients. PMID:17589644

  14. Barthes’ Irreversible Codes: An Intertextual Reading of James Joyce’s “Araby”

    Directory of Open Access Journals (Sweden)

    Seyed Ali Booryazadeh

    2014-01-01

    Full Text Available Roland Barthes believes that semiology is the study of how language embodies the world. Semiotic codes, the paths of this embodiment, accordingly arouse his attention. Barthes in a structural analysis of Balzac’s “Sarrasine” in S/Z expounds five types and functions of these codes: proairetic (basic narrative actions; hermeneutic (narrative turning points; cultural (prior social knowledge; semic (medium-related codes and symbolic (themes. This research in a parallel manner explicates that “Araby,” one of the most widely read of James Joyce’s short stories, is abounded with two of these irreversible codes (proairetic and hermeneutic. The present study furthermore tries to show how with resort to a series of signs and the idea of intertextuality a literary text can provide probable answers for some ambiguous and questionable lexias that comprise the story’s hermeneutic code. It demonstrates that not only can the text of “Araby” be encoded by the same criteria Barthes encoded “Sarrasine” but also Joyce himself presents particular names for these codes.Keywords: semiology, hermeneutic code, proairetic code, intertextuality, gnomon, simony, Araby, Dubliners

  15. Local equilibrium and the second law of thermodynamics for irreversible systems with thermodynamic inertia.

    Science.gov (United States)

    Glavatskiy, K S

    2015-10-28

    Validity of local equilibrium has been questioned for non-equilibrium systems which are characterized by delayed response. In particular, for systems with non-zero thermodynamic inertia, the assumption of local equilibrium leads to negative values of the entropy production, which is in contradiction with the second law of thermodynamics. In this paper, we address this question by suggesting a variational formulation of irreversible evolution of a system with non-zero thermodynamic inertia. We introduce the Lagrangian, which depends on the properties of the normal and the so-called "mirror-image" systems. We show that the standard evolution equations, in particular, the Maxwell-Cattaneo-Vernotte equation, can be derived from the variational procedure without going beyond the assumption of local equilibrium. We also argue that the second law of thermodynamics in non-equilibrium should be understood as a consequence of the variational procedure and the property of local equilibrium. For systems with instantaneous response this leads to the standard requirement of the local instantaneous entropy production being always positive. However, if a system is characterized by delayed response, the formulation of the second law of thermodynamics should be altered. In particular, the quantity, which is always positive, is not the instantaneous entropy production, but the entropy production averaged over a proper time interval. PMID:26520492

  16. Optimal thermoeconomic performance of an irreversible regenerative ferromagnetic Ericsson refrigeration cycle

    Science.gov (United States)

    Xu, Zhichao; Guo, Juncheng; Lin, Guoxing; Chen, Jincan

    2016-07-01

    On the basis of the Langevin theory of classical statistical mechanics, the magnetization, entropy, and iso-field heat capacity of ferromagnetic materials are analyzed and their mathematical expressions are derived. An irreversible regenerative Ericsson refrigeration cycle by using a ferromagnetic material as the working substance is established, in which finite heat capacity rates of low and high temperature reservoirs, non-perfect regenerative heat of the refrigeration cycle, additional regenerative heat loss, etc. are taken into account. Based on the regenerative refrigeration cycle model, a thermoeconomic function is introduced as one objective function and optimized with respect to the temperatures of the working substance in the two iso-thermal processes. By means of numerical calculation, the effects of the effective factor of the heat exchangers in high/low temperature reservoir sides, efficiency of the regenerator, heat capacity rate of the low temperature reservoir, and applied magnetic field on the optimal thermoeconomic function as well as the corresponding cooling rate and coefficient of performance are revealed. The results obtained in this paper can provide some theoretical guidance for the optimal design of actual regenerative magnetic refrigerator cycle.

  17. A comprehensive segmentation analysis of crude oil market based on time irreversibility

    Science.gov (United States)

    Xia, Jianan; Shang, Pengjian; Lu, Dan; Yin, Yi

    2016-05-01

    In this paper, we perform a comprehensive entropic segmentation analysis of crude oil future prices from 1983 to 2014 which used the Jensen-Shannon divergence as the statistical distance between segments, and analyze the results from original series S and series begin at 1986 (marked as S∗) to find common segments which have same boundaries. Then we apply time irreversibility analysis of each segment to divide all segments into two groups according to their asymmetry degree. Based on the temporal distribution of the common segments and high asymmetry segments, we figure out that these two types of segments appear alternately and do not overlap basically in daily group, while the common portions are also high asymmetry segments in weekly group. In addition, the temporal distribution of the common segments is fairly close to the time of crises, wars or other events, because the hit from severe events to oil price makes these common segments quite different from their adjacent segments. The common segments can be confirmed in daily group series, or weekly group series due to the large divergence between common segments and their neighbors. While the identification of high asymmetry segments is helpful to know the segments which are not affected badly by the events and can recover to steady states automatically. Finally, we rearrange the segments by merging the connected common segments or high asymmetry segments into a segment, and conjoin the connected segments which are neither common nor high asymmetric.

  18. The feasibility of using irreversible electroporation to introduce pores in bacterial cellulose scaffolds for tissue engineering.

    Science.gov (United States)

    Baah-Dwomoh, Adwoa; Rolong, Andrea; Gatenholm, Paul; Davalos, Rafael V

    2015-06-01

    This work investigates the feasibility of the use of irreversible electroporation (IRE) in the biofabrication of 3D cellulose nanofibril networks via the bacterial strain Gluconacetobacter xylinus. IRE uses electrical pulses to increase membrane permeability by altering the transmembrane potential; past a threshold, damage to the cell becomes too great and leads to cell death. We hypothesized that using IRE to kill the bacteria at specific locations and particular times, we could introduce conduits in the overall scaffold by preventing cellulose biosynthesis locally. Through mathematical modeling and experimental techniques, electrical effects were investigated and the parameters for IRE of G. xylinus were determined. We found that for a specific set of parameters, an applied electric field of 8 to 12.5 kV/cm, producing a local field of 3 kV/cm, was sufficient to kill most of the bacteria and create a localized pore. However, an applied electric field of 17.5 kV/cm was required to kill all. Results suggest that IRE may be an effective tool to create scaffolds with appropriate porosity for orthopedic applications. Ideally, these engineered scaffolds could be used to successfully treat osteochondral defects. PMID:25690311

  19. In vivo non-thermal irreversible electroporation impact on rat liver galvanic apparent internal resistance

    Science.gov (United States)

    Golberg, A.; Laufer, S.; Rabinowitch, H. D.; Rubinsky, B.

    2011-02-01

    Non-thermal irreversible electroporation (NTIRE) is a biophysical phenomenon which involves application of electric field pulses to cells or tissues, causing certain rearrangements in the membrane structure leading to cell death. The treated tissue ac impedance changes induced by electroporation were shown to be the indicators for NTIRE efficiency. In a previous study we characterized in vitro tissue galvanic apparent internal resistance (GAIR) changes due to NTIRE. Here we describe an in vivo study in which we monitored the GAIR changes of a rat liver treated by NTIRE. Electrical pulses were delivered through the same Zn/Cu electrodes by which GAIR was measured. GAIR was measured before and for 3 h after the treatment at 15 min intervals. The results were compared to the established ac bioimpedance measurement method. A decrease of 33% was measured immediately after the NTIRE treatment and a 40% decrease was measured after 3 h in GAIR values; in the same time 40% and 47% decrease respectively were measured by ac bioimpedance analyses. The temperature increase due to the NTIRE was only 0.5 °C. The results open the way for an inexpensive, self-powered in vivo real-time NTIRE effectiveness measurement.

  20. Magnetic irreversibility and pinning force density in the Mo100-xRex alloy superconductors

    Science.gov (United States)

    Sundar, Shyam; Chattopadhyay, M. K.; Sharath Chandra, L. S.; Roy, S. B.

    2015-12-01

    We have measured the isothermal field dependence of magnetization of the Mo100-xRex (15 ⩽ x ⩽ 48) alloys, and have estimated the critical current and pinning force density from these measurements. We have performed structural characterization of the above alloys using standard techniques, and analyzed the field dependence of critical current and pinning force density using existing theories. Our results indicate that dislocation networks and point defects like voids and interstitial imperfections are the main flux line pinning centers in the Mo100-xRex alloys in the intermediate fields, i.e., in the "small bundle" flux line pinning regime. In this regime, the critical current density is also quite robust against increasing magnetic field. In still higher fields, the critical current density is affected by flux creep. In the low field regime, on the other hand, the pinning of the flux lines seems to be influenced by the presence of two superconducting energy gaps in the Mo100-xRex alloys. This modifies the field dependence of critical current density, and also seems to contribute to the asymmetry in the magnetic irreversibility exhibited by the isothermal field dependence of magnetization.

  1. High critical current density and enhanced irreversibility field in superconducting MgB2 thin films.

    Science.gov (United States)

    Eom, C B; Lee, M K; Choi, J H; Belenky, L J; Song, X; Cooley, L D; Naus, M T; Patnaik, S; Jiang, J; Rikel, M; Polyanskii, A; Gurevich, A; Cai, X Y; Bu, S D; Babcock, S E; Hellstrom, E E; Larbalestier, D C; Rogado, N; Regan, K A; Hayward, M A; He, T; Slusky, J S; Inumaru, K; Haas, M K; Cava, R J

    2001-05-31

    The discovery of superconductivity at 39 K in magnesium diboride offers the possibility of a new class of low-cost, high-performance superconducting materials for magnets and electronic applications. This compound has twice the transition temperature of Nb3Sn and four times that of Nb-Ti alloy, and the vital prerequisite of strongly linked current flow has already been demonstrated. One possible drawback, however, is that the magnetic field at which superconductivity is destroyed is modest. Furthermore, the field which limits the range of practical applications-the irreversibility field H*(T)-is approximately 7 T at liquid helium temperature (4.2 K), significantly lower than about 10 T for Nb-Ti (ref. 6) and approximately 20 T for Nb3Sn (ref. 7). Here we show that MgB2 thin films that are alloyed with oxygen can exhibit a much steeper temperature dependence of H*(T) than is observed in bulk materials, yielding an H* value at 4.2 K greater than 14 T. In addition, very high critical current densities at 4.2 K are achieved: 1 MA cm-2 at 1 T and 105 A cm-2 at 10 T. These results demonstrate that MgB2 has potential for high-field superconducting applications.

  2. Optimal analysis on the performance of an irreversible harmonic quantum Brayton refrigeration cycle.

    Science.gov (United States)

    Lin, Bihong; Chen, Jincan

    2003-11-01

    An irreversible model of a quantum refrigeration cycle working with many noninteracting harmonic oscillators is established. The refrigeration cycle consists of two adiabatic and two constant-frequency processes. The general performance characteristics of the cycle are investigated, based on the quantum master equation and the semigroup approach. The expressions for several important performance parameters such as the coefficient of performance, cooling rate, power input, and rate of entropy production are derived. By using numerical solutions, the cooling rate of the refrigeration cycle subject to finite cycle duration is optimized. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal region of the coefficient of performance and the optimal ranges of temperatures of the working substance and times spent on the two constant-frequency processes are determined. Moreover, the optimal performance of the cycle in the high-temperature limit is compared with that of a classical Brayton refrigerator working with an ideal gas. The results obtained here show that in the high-temperature limit a harmonic quantum Brayton cycle may be equivalent to a classical Brayton cycle. PMID:14682856

  3. Post-hatch heat warms adult beaks: irreversible physiological plasticity in Japanese quail.

    Science.gov (United States)

    Burness, Gary; Huard, Jacqueline R; Malcolm, Emily; Tattersall, Glenn J

    2013-09-22

    Across taxa, the early rearing environment contributes to adult morphological and physiological variation. For example, in birds, environmental temperature plays a key role in shaping bill size and clinal trends across latitudinal/thermal gradients. Such patterns support the role of the bill as a thermal window and in thermal balance. It remains unknown whether bill size and thermal function are reversibly plastic. We raised Japanese quail in warm (30°C) or cold (15°C) environments and then at a common intermediate temperature. We predicted that birds raised in cold temperatures would develop smaller bills than warm-reared individuals, and that regulation of blood flow to the bill in response to changing temperatures would parallel the bill's role in thermal balance. Cold-reared birds developed shorter bills, although bill size exhibited 'catch-up' growth once adults were placed at a common temperature. Despite having lived in a common thermal environment as adults, individuals that were initially reared in the warmth had higher bill surface temperatures than cold-reared individuals, particularly under cold conditions. This suggests that blood vessel density and/or the control over blood flow in the bill retained a memory of early thermal ontogeny. We conclude that post-hatch temperature reversibly affects adult bill morphology but irreversibly influences the thermal physiological role of bills and may play an underappreciated role in avian energetics.

  4. In vivo non-thermal irreversible electroporation impact on rat liver galvanic apparent internal resistance

    Energy Technology Data Exchange (ETDEWEB)

    Golberg, A; Laufer, S [Center for Bioengineering in the Service of Humanity and Society, School of Computer Science and Engineering, Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Rabinowitch, H D [Robert H Smith Faculty of Agriculture, Food and Environment, Robert H Smith Institute of Plant Science and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76 100 (Israel); Rubinsky, B, E-mail: Rabin@agri.huji.ac.il [Department of Mechanical Engineering, Graduate Program in Biophysics, University of California at Berkeley, Berkeley, CA 84720 (United States)

    2011-02-21

    Non-thermal irreversible electroporation (NTIRE) is a biophysical phenomenon which involves application of electric field pulses to cells or tissues, causing certain rearrangements in the membrane structure leading to cell death. The treated tissue ac impedance changes induced by electroporation were shown to be the indicators for NTIRE efficiency. In a previous study we characterized in vitro tissue galvanic apparent internal resistance (GAIR) changes due to NTIRE. Here we describe an in vivo study in which we monitored the GAIR changes of a rat liver treated by NTIRE. Electrical pulses were delivered through the same Zn/Cu electrodes by which GAIR was measured. GAIR was measured before and for 3 h after the treatment at 15 min intervals. The results were compared to the established ac bioimpedance measurement method. A decrease of 33% was measured immediately after the NTIRE treatment and a 40% decrease was measured after 3 h in GAIR values; in the same time 40% and 47% decrease respectively were measured by ac bioimpedance analyses. The temperature increase due to the NTIRE was only 0.5 deg. C. The results open the way for an inexpensive, self-powered in vivo real-time NTIRE effectiveness measurement.

  5. Irreversible electroporation and the pancreas:What we know and where we are going?

    Institute of Scientific and Technical Information of China (English)

    Shamar; J; Young

    2015-01-01

    Pancreatic adenocarcinoma continues to have a poor prognosis with 1 and 5 years survival rates of 27% and 6% respectively. The gold standard of treatment is resection, however, only approximately 10% of patients present with resectable disease. Approximately 40% of patients present with disease that is too locally advancedto resect. There is great interest in improving outcomes in this patient population and ablation techniques have been investigated as a potential solution. Unfortunately early investigations into thermal ablation techniques, particularly radiofrequency ablation, resulted in unacceptably high morbidity rates. Irreversible electroporation(IRE) has been introduced and is promising as it does not rely on thermal energy and has shown an ability to leave structural cells such as blood vessels and bile ducts intact during animal studies. IRE also does not suffer from heat sink effect, a concern given the large number of blood vessels surrounding the pancreas. IRE showed significant promise during preclinical animal trials and as such has moved on to clinical testing. There are as of yet only a few studies which look at the applications of IRE within humans in the setting of pancreatic adenocarcinoma. This paper reviews the basic principles, techniques, and current clinical data available on IRE.

  6. A Parametric Study Delineating Irreversible Electroporation from Thermal Damage Based on a Minimally Invasive Intracranial Procedure

    Directory of Open Access Journals (Sweden)

    Ellis Thomas L

    2011-04-01

    Full Text Available Abstract Background Irreversible electroporation (IRE is a new minimally invasive technique to kill undesirable tissue in a non-thermal manner. In order to maximize the benefits from an IRE procedure, the pulse parameters and electrode configuration must be optimized to achieve complete coverage of the targeted tissue while preventing thermal damage due to excessive Joule heating. Methods We developed numerical simulations of typical protocols based on a previously published computed tomographic (CT guided in vivo procedure. These models were adapted to assess the effects of temperature, electroporation, pulse duration, and repetition rate on the volumes of tissue undergoing IRE alone or in superposition with thermal damage. Results Nine different combinations of voltage and pulse frequency were investigated, five of which resulted in IRE alone while four produced IRE in superposition with thermal damage. Conclusions The parametric study evaluated the influence of pulse frequency and applied voltage on treatment volumes, and refined a proposed method to delineate IRE from thermal damage. We confirm that determining an IRE treatment protocol requires incorporating all the physical effects of electroporation, and that these effects may have significant implications in treatment planning and outcome assessment. The goal of the manuscript is to provide the reader with the numerical methods to assess multiple-pulse electroporation treatment protocols in order to isolate IRE from thermal damage and capitalize on the benefits of a non-thermal mode of tissue ablation.

  7. Irreversible Electroporation Adjacent to the Rectum: Evaluation of Pathological Effects in a Pig Model

    Energy Technology Data Exchange (ETDEWEB)

    Schoellnast, Helmut [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States); Monette, Sebastien [Memorial Sloan-Kettering Cancer Center, Weill Cornell Medical College, Rockefeller University, Laboratory of Comparative Pathology (United States); Ezell, Paula C. [Memorial Sloan-Kettering Cancer Center, Weill Cornell Medical College, Rockefeller University, Research Animal Resource Center (United States); Single, Gordon [AngioDynamics Inc. (United States); Maybody, Majid [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States); Weiser, Martin R.; Fong Yuman [Memorial Sloan-Kettering Cancer Center, Department of Surgery (United States); Solomon, Stephen B., E-mail: solomons@mskcc.org [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States)

    2013-02-15

    To evaluate the effects of irreversible electroporation (IRE) on the rectum wall after IRE applied adjacent to the rectum. CT-guided IRE adjacent to the rectum wall was performed in 11 pigs; a total of 44 lesions were created. In five pigs, ablations were performed without a water-filled endorectal coil (group A); in six pigs, ablation was performed with the coil to avoid displacement of the rectum wall (group B). The pigs were killed after 7-15 days and the rectums were harvested for pathological evaluation. There was no evidence of perforation on gross postmortem examination. Perirectal muscle lesions were observed in 18 of 20 ablations in group A and in 21 of 24 ablations in group B. Inflammation and fibrosis of the muscularis propria was observed in ten of 18 lesions in group A and in ten of 21 lesions in group B. In group A, findings were limited to the external layer of the muscularis propria except for one lesion; in group B, findings were transmural in all cases. Transmural necrosis with marked suppurative mucosal inflammation was observed in seven of 21 lesions in group B and in no lesion in group A. IRE-ablation adjacent to the rectum may be uneventful if the rectum wall is mobile and able to contract. IRE-ablation of the rectum may be harmful if the rectum wall is fixed adjacent to the IRE-probe.

  8. Local Control of Perivascular Malignant Liver Lesions Using Percutaneous Irreversible Electroporation: Initial Experiences

    Energy Technology Data Exchange (ETDEWEB)

    Eller, Achim, E-mail: Achim.Eller@uk-erlangen.de; Schmid, Axel, E-mail: axel.schmid@uk-erlangen.de [University Hospital Erlangen, University of Erlangen-Nuremberg, Department of Radiology (Germany); Schmidt, Joachim, E-mail: joachim.schmidt@kfa.imed.uni-erlangen.de [University Hospital Erlangen, University of Erlangen-Nuremberg, Department of Anesthesiology (Germany); May, Matthias, E-mail: matthias.may@uk-erlangen.de; Brand, Michael, E-mail: michael.brand@uk-erlangen.de; Saake, Marc, E-mail: marc.saake@uk-erlangen.de; Uder, Michael, E-mail: michael.uder@uk-erlangen.de; Lell, Michael, E-mail: michael.lell@uk-erlangen.de [University Hospital Erlangen, University of Erlangen-Nuremberg, Department of Radiology (Germany)

    2015-02-15

    PurposeThis study was designed to assess efficacy and safety in the treatment of perivascular malignant liver lesions using percutaneous, computed tomography (CT)-guided irreversible electroporation (IRE).MethodsFourteen patients (mean age 58 ± 11 years) with 18 malignant liver lesions were consecutively enrolled in this study. IRE was performed in patients not eligible for surgery and lesions abutting large vessels or bile ducts. Follow-up exams were performed using multislice-CT (MS-CT) or MRI.ResultsMedium lesion diameter was 20 ± 5 mm. Ten of 14 (71 %) were successfully treated with no local recurrence to date (mean follow-up 388 ± 160 days). One case left initial tumor control unclear and additional RFA was performed 4 weeks after IRE. Complications occurred in 4 of 14 (29 %) cases. In one case, intervention was terminated and abdominal bleeding required laparotomy. In two cases, a postinterventional hematothorax required intervention. In another case, abdominal bleeding could be managed conservatively. No complications related to the bile ducts occurred.ConclusionsPercutaneous IRE seems to be effective in perivascular lesions but is associated with a higher complication rate compared with thermoablative techniques.

  9. Self-regenerating and hybrid irreversible/reversible PDMS microfluidic devices

    Science.gov (United States)

    Shiroma, Letícia S.; Piazzetta, Maria H. O.; Duarte-Junior, Gerson F.; Coltro, Wendell K. T.; Carrilho, Emanuel; Gobbi, Angelo L.; Lima, Renato S.

    2016-05-01

    This paper outlines a straightforward, fast, and low-cost method to fabricate polydimethylsiloxane (PDMS) chips. Termed sandwich bonding (SWB), this method requires only a laboratory oven. Initially, SWB relies on the reversible bonding of a coverslip over PDMS channels. The coverslip is smaller than the substrate, leaving a border around the substrate exposed. Subsequently, a liquid composed of PDMS monomers and a curing agent is poured onto the structure. Finally, the cover is cured. We focused on PDMS/glass chips because of their key advantages in microfluidics. Despite its simplicity, this method created high-performance microfluidic channels. Such structures featured self-regeneration after leakages and hybrid irreversible/reversible behavior. The reversible nature was achieved by removing the cover of PDMS with acetone. Thus, the PDMS substrate and glass coverslip could be detached for reuse. These abilities are essential in the stages of research and development. Additionally, SWB avoids the use of surface oxidation, half-cured PDMS as an adhesive, and surface chemical modification. As a consequence, SWB allows surface modifications before the bonding, a long time for alignment, the enclosure of sub-micron channels, and the prototyping of hybrid devices. Here, the technique was successfully applied to bond PDMS to Au and Al.

  10. The effect of small intestine heterogeneity on irreversible electroporation treatment planning.

    Science.gov (United States)

    Phillips, Mary

    2014-09-01

    Nonthermal irreversible electroporation (NTIRE) is an ablation modality that utilizes microsecond electric fields to produce nanoscale defects in the cell membrane. This results in selective cell death while preserving all other molecules, including the extracellular matrix. Here, finite element analysis and experimental results are utilized to examine the effect of NTIRE on the small intestine due to concern over collateral damage to this organ during NTIRE treatment of abdominal cancers. During previous studies, the electrical treatment parameters were chosen based on a simplified homogeneous tissue model. The small intestine, however, has very distinct layers, and a more realistic model is needed to further develop this technology for precise clinical applications. This study uses a two-dimensional finite element solution of the Laplace and heat conduction equations to investigate how small intestine heterogeneities affect the electric field and temperature distribution. Experimental results obtained by applying NTIRE to the rat small intestine in vivo support the heterogeneous effect of NTIRE on the tissue. The numerical modeling indicates that the electroporation parameters chosen for this study avoid thermal damage to the tissue. This is supported by histology obtained from the in vivo study, which showed preservation of extracellular structures. The finite element model also indicates that the heterogeneous structure of the small intestine has a significant effect on the electric field and volume of cell ablation during electroporation and could have a large impact on the extent of treatment. The heterogeneous nature of the tissue should be accounted for in clinical treatment planning.

  11. Determination of (111) ordered domains on platinum electrodes by irreversible adsorption of bismuth.

    Science.gov (United States)

    Rodríguez, Paramaconi; Solla-Gullón, José; Vidal-Iglesias, Francisco J; Herrero, Enrique; Aldaz, Antonio; Feliu, Juan M

    2005-08-15

    Irreversible adsorbed bismuth can be used to determine the fraction of (111) domains on a given platinum sample. On Pt(111) electrodes, the surface redox process of adsorbed bismuth takes place at 0.63 V in a well-defined peak. The behavior of this redox process on the Pt(111) vicinal surfaces indicates that the bismuth atoms involved in the redox process are only those deposited on the (111) terrace sites and that the charge under the peak at 0.63 V is directly proportional to the number of sites on (111) ordered domains (terraces). The good linear relationship obtained between the charge for the bismuth redox process and the number of (111) terrace sites on the vicinal surfaces allows construction of a calibration curve. This calibration curve has been used to directly estimate the amount of (111) ordered domain terrace sites on polycrystalline platinum samples with different surface ordered domains. The results agree with what we would expect from our knowledge of these surfaces. PMID:16097774

  12. Enzymatic treatment for controlling irreversible membrane fouling in cross-flow humic acid-fed ultrafiltration

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Chien-Hwa [Department of Civil and Environment Engineering, Nanya Institute of Technology, Taoyuan, Taiwan (China); Fang, Lung-Chen; Lateef, Shaik Khaja [Graduate Institute of Environmental Engineering, National Taiwan University, Taipei, Taiwan (China); Wu, Chung-Hsin, E-mail: chunghsinwu@yahoo.com.tw [Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, 415 Chien Kung Road, Kaohsiung 807, Taiwan (China); Lin, Cheng-Fang [Graduate Institute of Environmental Engineering, National Taiwan University, Taipei, Taiwan (China)

    2010-05-15

    Exploring reasonable ways to remove foulant is of great importance in order to allow sustainable operation of ultrafiltration (UF) membranes in water/wastewater treatment technology. Compounds of organic and inorganic origin largely contribute to irreversible fouling. This study attempted to remove problem of UF membrane fouling by using four different enzymes including {alpha}-amylase, lipase, cellulase and protease. This investigation showed that none of the above mentioned enzymes was found to be effective for the removal of foulant when used alone. However, when these enzymes were used in combination with NaOH and citric acid, about 90% cleaning was achieved. The addition of non-ionic surfactant to the enzymatic solution appears to increase the efficiency of flux recovery by reducing the adhesion of foulant species to the membrane surface through the decrease of contact angle. Field emission gun scanning electron microscopy, Fourier transform infrared spectroscopy and atomic force microscopy (AFM) techniques were employed to qualitatively illustrate the foulant characteristics. The surface roughness through AFM was used to explain the potential mechanism for the enzymatic cleaning.

  13. Irreversible electroporation and apoptosis in human liver cancer cells induced by nanosecond electric pulses.

    Science.gov (United States)

    Xiao, Deyou; Yao, Chenguo; Liu, Huan; Li, Chengxiang; Cheng, Jie; Guo, Fei; Tang, Liling

    2013-10-01

    The goal of this study was to assess the effect of nanosecond electric pulses on HepG2 human liver cancer cells. Electric pulses with a high strength of 10 kV/cm, duration of 500 ns and frequency of 1 Hz were applied to the cells. After delivery of electric pulses, apoptosis, intracellular calcium ion concentrations, transmembrane mitochondrial potentials, electropermeabilization and recovery from electropermeabilization in cells were investigated. The results showed that electric pulse treatment for 20 s and more could trigger apoptosis in cells. Real-time observation indicated an immediate increase in intracellular calcium ion concentration and a dramatic decrease in mitochondrial membrane potential in cells responding to electric pulses. In subsequent experiments, propidium iodide uptake in cells emerged after exposure to electric pulses, indicating electropermeabilization of the cell membrane. Furthermore, recovery from electropermeabilization was not observed even 4 h after the stimulation, demonstrating that irreversible electropermeabilization was induced by electric pulses. In conclusion, electric pulses with a high strength and nanosecond duration can damage cancer cells, accompanied by a series of intracellular changes, providing strong evidence for the application of electric pulses in cancer treatment. PMID:23740887

  14. Comparison of the irreversible thermomagnetic behaviour of some ferro- and ferrimagnetic systems

    Indian Academy of Sciences (India)

    P S Anil Kumar; P A Joy; S K Date

    2000-04-01

    The magnetic behaviour of two ferromagnetic oxides and two ferrimagnetic oxides (ferrites) are compared to study the effect of magnetocrystalline anisotropy on thermal-history-dependence of magnetization of these ordered magnetic systems. All four compounds show thermomagnetic irreversibility (FC > ZFC) below a certain temperature, irr. The highly anisotropic ferromagnetic oxide, SrRuO3 and the hard ferrite, SrFe12O19 show sharp peaks below in their ZFC() curves, whereas for the soft ferrite Ni0.8Zn0.2Fe2O4 and the low anisotropic ferromagnetic oxide La0.7Ca0.3MnO3 only a broad maximum is observed in ZFC, when measured in small magnetic fields. The shapes of the ZFC() curves are inversely-related to the magnitude of the coercivities (c) of the compounds in relation to the applied field, and the temperature dependence of (c). FCand ZFC are related through the coercivity for all four magnetic systems.

  15. Mortalidad intrahospitalaria por accidente cerebrovascular

    Directory of Open Access Journals (Sweden)

    Federico Rodríguez Lucci

    2013-08-01

    Full Text Available La mortalidad global por accidente cerebrovascular (ACV ha disminuido en las últimas tres décadas, probablemente debido a un mejor control de los factores de riesgo vascular. La mortalidad hospitalaria por ACV ha sido tradicionalmente estimada entre 6 y 14% en la mayoría de las series comunicadas. Sin embargo, los datos de ensayos clínicos recientes sugieren que esta cifra sería sustancialmente menor. Se revisaron datos de pacientes internados con diagnóstico de ACV del Banco de Datos de Stroke de FLENI y los registros institucionales de mortalidad entre los años 2000 y 2010. Los subtipos de ACV isquémicos se clasificaron según criterios TOAST y los ACV hemorrágicos en hematomas intrapanquimatosos, hemorragias subaracnoideas aneurismáticas, malformaciones arteriovenosas y otros hematomas intraparenquimatosos. Se analizaron 1514 pacientes, 1079 (71% con ACV isquémico (grandes vasos 39%, cardioembólicos 27%, lacunares 9%, etiología indeterminada 14%, otras etiologías 11% y 435 (29% con ACV hemorrágico (intraparenquimatosos 27%, hemorragia subaracnoidea 30%, malformaciones arteriovenosas 25% y otros hematomas espontáneos 18%. Se registraron 38 muertes intrahospitalarias (17 ACV isquémicos y 21 ACV hemorrágicos, representando una mortalidad global del 2.5% (1.7% en ACV isquémicos y 4.8% en ACV hemorrágicos. No se registraron muertes asociadas al uso de fibrinolíticos endovenosos. La mortalidad intrahospitalaria en pacientes con ACV isquémico y hemorrágico en nuestro centro fue baja. El manejo en un centro dedicado a las enfermedades neurológicas y el enfoque multidisciplinario por personal médico y no médico entrenado en el cuidado de la enfermedad cerebrovascular podrían explicar, al menos en parte, estos resultados.

  16. Irreversibility Analysis of Non Isothermal Flat Plate Solar Collectors for Air Heating with a Dimensionless Model

    Directory of Open Access Journals (Sweden)

    Baritto-Loreto Miguel Leonardo

    2013-04-01

    Full Text Available En el presente trabajo, el modelo adimensional desarrollado y validado por Baritto y Bracamonte (2012 para describir el comportamiento térmico de colectores solares de placas planas sin cubierta transparente, se complementa con la ecuación adimensional de balance de entropía para un elemento diferencial de colector solar. El modelo se resuelve para un amplio rango de valores de relaciones de aspecto y número de flujo de masa. A partir de los resultados del modelo se desarrolla un análisis detallado de la influencia de estos parámetros sobre la distribución de irreversibilidades internas a lo largo del colector. Adicionalmente se estudia la influencia de estos parámetros sobre los números de generación de entropía por fricción viscosa, por transferencia de calor y total. Se encuentra que existen combinaciones de los parámetros antes mencionados, para los cuales, la operación del colector es termodinámicamente óptima para números de flujo de masa elevados.

  17. Experimental study on apoptosis and necrosis of goat hepatocytes induced by irreversible electroporation

    Directory of Open Access Journals (Sweden)

    Ying LIU

    2011-04-01

    Full Text Available Objective To investigate the ablation effects of irreversible electroporation(IRE on goat liver tissues,and analyze the relationship of apoptosis and necrosis of hepatocytes to the distribution of electric fields.Methods IRE was performed on goats of 4-6 months old as follows: the electrodes were targeted to goats’ liver tissue under ultrasonic guidance,and the pulse electric fields(PEFs were exerted with 120 pulses of permanent duration(100μs,frequency(1Hz and voltage(2000V.Animals were sacrificed 24 hours after treatment,the samples of liver tissues were harvested,including the tissues surrounding the electrodes and that of the border area,with normal tissue as control.The specimens were prepared for HE staining to observe the histopathological changes.DNA ladder analysis and TUNEL test were performed to determine apoptosis,and flow cytometry(FCM was employed to analyze the changes in cell cycle.Results Pathologically,cell necrosis was found in ablation zone with a distinguish border line between the normal tissue,and coagulate necrosis was seen in the area surrounding electrodes.TUNEL test showed apoptotic cells,with heavy black staining of the nuclei and light brownish yellow in cytoplasm,and they were mainly aggregated in the border between treated and normal tissues.In this area the ladder strips of 400 to 1000bp were also detected by DNA electrophoragram.Moreover,hypodiploid peak was found,prior to the diploid peak,by FCM analysis in the hepatocytes obtained from ablated zone.Conclusion In goats’ liver tissue ablated by means of IRE,coagulation necrosis may appear in the areas under highest electric field intensity surrounding the central area of electrodes,and the apoptosis of hepatocytes may be found in the border areas along with the attenuation of electric field intensity.

  18. Planning Irreversible Electroporation in the Porcine Kidney: Are Numerical Simulations Reliable for Predicting Empiric Ablation Outcomes?

    International Nuclear Information System (INIS)

    PurposeNumerical simulations are used for treatment planning in clinical applications of irreversible electroporation (IRE) to determine ablation size and shape. To assess the reliability of simulations for treatment planning, we compared simulation results with empiric outcomes of renal IRE using computed tomography (CT) and histology in an animal model.MethodsThe ablation size and shape for six different IRE parameter sets (70–90 pulses, 2,000–2,700 V, 70–100 µs) for monopolar and bipolar electrodes was simulated using a numerical model. Employing these treatment parameters, 35 CT-guided IRE ablations were created in both kidneys of six pigs and followed up with CT immediately and after 24 h. Histopathology was analyzed from postablation day 1.ResultsAblation zones on CT measured 81 ± 18 % (day 0, p ≤ 0.05) and 115 ± 18 % (day 1, p ≤ 0.09) of the simulated size for monopolar electrodes, and 190 ± 33 % (day 0, p ≤ 0.001) and 234 ± 12 % (day 1, p ≤ 0.0001) for bipolar electrodes. Histopathology indicated smaller ablation zones than simulated (71 ± 41 %, p ≤ 0.047) and measured on CT (47 ± 16 %, p ≤ 0.005) with complete ablation of kidney parenchyma within the central zone and incomplete ablation in the periphery.ConclusionBoth numerical simulations for planning renal IRE and CT measurements may overestimate the size of ablation compared to histology, and ablation effects may be incomplete in the periphery

  19. Short- and Mid-term Effects of Irreversible Electroporation on Normal Renal Tissue: An Animal Model

    International Nuclear Information System (INIS)

    Irreversible electroporation (IRE) is a novel nonthermal tissue ablation technique by high current application leading to apoptosis without affecting extracellular matrix. Previous results of renal IRE shall be supplemented by functional MRI and differentiated histological analysis of renal parenchyma in a chronic treatment setting. Three swine were treated with two to three multifocal percutaneous IRE of the right kidney. MRI was performed before, 30 min (immediate-term), 7 days (short-term), and 28 days (mid-term) after IRE. A statistical analysis of the lesion surrounded renal parenchyma intensities was made to analyze functional differences depending on renal part, side and posttreatment time. Histological follow-up of cortex and medulla was performed after 28 days. A total of eight ablations were created. MRI showed no collateral damage of surrounded tissue. The highest visual contrast between lesions and normal parenchyma was obtained by T2-HR-SPIR-TSE-w sequence of DCE-MRI. Ablation zones showed inhomogeneous necroses with small perifocal edema in the short-term and sharp delimitable scars in the mid-term. MRI showed no significant differences between adjoined renal parenchyma around ablations and parenchyma of untreated kidney. Histological analysis demonstrated complete destruction of cortical glomeruli and tubules, while collecting ducts, renal calyxes, and pelvis of medulla were preserved. Adjoined kidney parenchyma around IRE lesions showed no qualitative differences to normal parenchyma of untreated kidney. This porcine IRE study reveals a multifocal renal ablation, while protecting surrounded renal parenchyma and collecting system over a mid-term period. That offers prevention of renal function ablating centrally located or multifocal renal masses.

  20. The Effects of Metallic Implants on Electroporation Therapies: Feasibility of Irreversible Electroporation for Brachytherapy Salvage

    International Nuclear Information System (INIS)

    Purpose: Electroporation-based therapies deliver brief electric pulses into a targeted volume to destabilize cellular membranes. Nonthermal irreversible electroporation (IRE) provides focal ablation with effects dependent on the electric field distribution, which changes in heterogeneous environments. It should be determined if highly conductive metallic implants in targeted regions, such as radiotherapy brachytherapy seeds in prostate tissue, will alter treatment outcomes. Theoretical and experimental models determine the impact of prostate brachytherapy seeds on IRE treatments. Materials and Methods: This study delivered IRE pulses in nonanimal, as well as in ex vivo and in vivo tissue, with and in the absence of expired radiotherapy seeds. Electrical current was measured and lesion dimensions were examined macroscopically and with magnetic resonance imaging. Finite-element treatment simulations predicted the effects of brachytherapy seeds in the targeted region on electrical current, electric field, and temperature distributions. Results: There was no significant difference in electrical behavior in tissue containing a grid of expired radiotherapy seeds relative to those without seeds for nonanimal, ex vivo, and in vivo experiments (all p > 0.1). Numerical simulations predict no significant alteration of electric field or thermal effects (all p > 0.1). Histology showed cellular necrosis in the region near the electrodes and seeds within the ablation region; however, there were no seeds beyond the ablation margins. Conclusion: This study suggests that electroporation therapies can be implemented in regions containing small metallic implants without significant changes to electrical and thermal effects relative to use in tissue without the implants. This supports the ability to use IRE as a salvage therapy option for brachytherapy