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Sample records for converting venous acid-base

  1. Calculating acid-base and oxygenation status during COPD exacerbation using mathematically arterialised venous blood

    DEFF Research Database (Denmark)

    Rees, Stephen Edward; Rychwicka-Kielek, Beate A; Andersen, Bjarne F

    2012-01-01

    Abstract Background: Repeated arterial puncture is painful. A mathematical method exists for transforming peripheral venous pH, PCO2 and PO2 to arterial eliminating the need for arterial sampling. This study evaluates this method to monitor acid-base and oxygenation during admission...... for exacerbation of chronic obstructive pulmonary disease (COPD). Methods: Simultaneous arterial and peripheral venous blood was analysed. Venous values were used to calculate arterial pH, PCO2 and PO2, with these compared to measured values using Bland-Altman analysis and scatter plots. Calculated values of PO2......H, PCO2 and PO2 were 7.432±0.047, 6.8±1.7 kPa and 9.2±1.5 kPa, respectively. Calculated and measured arterial pH and PCO2 agreed well, differences having small bias and SD (0.000±0.022 pH, -0.06±0.50 kPa PCO2), significantly better than venous blood alone. Calculated PO2 obeyed the clinical rules...

  2. Influence of different storage times and temperatures on blood gas and acid-base balance in ovine venous blood.

    Science.gov (United States)

    Hussein, H A; Aamer, A A

    2013-01-01

    The present study was designed to investigate the effects of storage temperature and time on blood gas and acid-base balance of ovine venous blood. Ten clinically healthy sheep were used in this study. A total number of 30 blood samples, were divided into three different groups, and were stored in a refrigerator adjusted to +4 ºC (Group I, n = 10), at RT of about 22-25 ºC (Group II, n = 10) and in an incubator adjusted to 37 ºC (Group III, n = 10) for up to 48 h. Blood samples were analysed for blood gas and acid-base indices at 0, 1, 2, 3, 4, 5, 6, 12, 24 and 48 h of storage. In comparison to the baseline value (0), there were significant decreases of blood pH of samples stored at RT and in the incubator after 1 h (ppO2 values were significantly higher for Group I after 2 h and for Groups II and III after 1 h (preference range and it may be of clinical diagnostic use for up to 6 h.

  3. Influence of different storage times and temperatures on blood gas and acid-base balance in ovine venous blood

    Directory of Open Access Journals (Sweden)

    H.A. Hussein

    2013-01-01

    Full Text Available The present study was designed to investigate the effects of storage temperature and time on blood gas and acid-base balance of ovine venous blood. Ten clinically healthy sheep were used in this study. A total number of 30 blood samples, were divided into three different groups, and were stored in a refrigerator adjusted to +4 ºC (Group I, n = 10, at RT of about 22-25 ºC (Group II, n = 10 and in an incubator adjusted to 37 ºC (Group III, n = 10 for up to 48 h. Blood samples were analysed for blood gas and acid-base indices at 0, 1, 2, 3, 4, 5, 6, 12, 24 and 48 h of storage. In comparison to the baseline value (0, there were significant decreases of blood pH of samples stored at RT and in the incubator after 1 h (p<0.05, the pH value of refrigerated blood samples exhibited insignificant changes during the study (p<0.05. Mean values of pCO2 showed a significant increase in Group I and Group III after 1 h then a progressive decrease after 12 h in all Groups. Mean pO2 values were significantly higher for Group I after 2 h and for Groups II and III after 1 h (p<0.05. In general, base excess decreased significantly for all the groups during the study especially in Groups II and III. In comparison with baseline values, in all groups, bicarbonate (HCO3 increased between 1 h and 6 h (p<0.05, and later decreased at the end of the study (p<0.05. In conclusion, status of acid-base indices of the samples stored at refrigerator and RT were found within normal reference range and it may be of clinical diagnostic use for up to 6 h.

  4. L-lysine escinat, thiotriazolin, gordox and mydocalm influence on oxygen tension in the intestinal wall and acid-base balance and limited proteolysis in intestinal venous blood in terms of intraabdominal hypertension modeling

    Directory of Open Access Journals (Sweden)

    Sapegin V.I.

    2014-11-01

    Full Text Available In acute experiments on rabbits there were studied changes in oxygen tension in the intestinal wall tissues, acid-base balance and limited proteolysis and its inhibitors in intestinal venous blood, protective action of L-lysine escinat (0,15 mg/kg / single dose, thiotriazolin (25 mg/kg / single dose, aprotinin (gordox (10,000 units/kg / single dose in sequential modeling of standard levels increasing of intra-abdominal hypertension (IAH — 50, 100, 150, 200, 250, 300, 350 m H2O, and also of tolperison (mydocalm (5 mg/kg / single dose on modeling of stable 3-hour IAH 200 m H2O. The IAH modeling was performed by means of stand of our construction. Under the influence of IAH the compensated metabolic acidosis in intestinal venous blood with a compensative hyperpnoe develops, decline of oxygen tension in tissues and activating of a limited proteolysis as well as decline of its inhibitors activity in intestinal venous blood occur. By the degree of metabolic acidosis prevention investigational preparations were distributed as follows gordox > thiotriazolin = L-lysine escinat = mydocalm, and by prevention of decline of oxygen tension in tissues — thiotriazolin > L-lysine escinat > mydocalm > gordox, it is is connected with different rate of methabolic products excretion into the blood, due to the influence on blood circulation and transcapilary exchange. By the degree of prevention of proteolytic activity and inhibitory potential changes, investigational preparations were distributed as follows: gordox > mydocalm > thiotriazolin > L-lysine escinat, this is connected with inhibition of proteolysis in gordox, and in other ones – with reduction of ischemic damage of tissues. Owing to different mechanism of action thiotriazolin, L-lysine escinat and mydocalm may be simultaneously recommended for a conservative treatment of patients with intraabdominal hypertension syndrome.

  5. Uso de sangue arterial e venoso no exame do equilíbrio ácido-básico de novilhos normais ou com acidose metabólica Arterial and venous blood in the assessment of blood gas and acid-base status in healthy steers or steers with metabolic acidosis

    Directory of Open Access Journals (Sweden)

    Maria Claudia Araripe Sucupira

    2003-10-01

    Full Text Available Doze novilhos foram utilizados para comparar os resultados hemogasométricos de sangue arterial e venoso. Esses animais foram divididos em três grupos idênticos, recebendo: 1- dieta balanceada, proporcionando ganho de peso de 600g/d; 2- dieta de mantença em proteína e energia e 3- dieta com teores 20% abaixo da mantença. Amostras de sangue arterial (artéria auricular caudal e venoso (veia jugular foram colhidas por 11 quinzenas consecutivas, num total de 132 amostras. Ao término do experimento, os animais dos grupos 2 e principalmente 3 apresentaram acidose metabólica moderada. Maiores valores de pH e de pO2 foram constatados no sangue arterial enquanto os teores de bicarbonato, TCO2, BE e pCO2 foram superiores no sangue venoso. Existiram altas correlações entre os valores do sangue arterial e venoso para o pH (r = 0,81, bicarbonato e TCO2 (r = 0,94, sendo esta correlação média, mas significativa, no caso da pCO2 (r = 0,56 e inexistente na pO2 (r= -0,06. Quanto maiores foram os valores de pCO2 maiores foram os teores de bicarbonato (r = 0,54 e TCO2 (r =0,56. Apesar das discrepâncias de pH, das concentrações de bicarbonato, TCO2, e mesmo de pCO2 obtidos no sangue venoso e arterial, é possível estimar, adequadamente, a partir do primeiro esses valores nas amostras arteriais em novilhos normais e com moderado grau de acidose metabólica. Nos casos de alterações respiratórias, amostras de sangue arterial devem ser colhidas para determinação de pO2. A colheita de sangue venoso foi mais facilmente realizada que do sangue arterial.Twelve steers were used to compare the blood gas and acid-base status. The animals were randomly divided in three equal groups according to the following diets: 1- adequate, for gaining 600g/head/d ; 2- protein and energy levels to meet the maintenence; 3- protein and energy 20% below the maintenance levels. One hundred thirty-two arterial blood (caudal auricular artery or venous blood (jugular vein

  6. Venous Ulcers

    Science.gov (United States)

    Caprini, J.A.; Partsch, H.; Simman, R.

    2013-01-01

    Venous leg ulcers are the most frequent form of wounds seen in patients. This article presents an overview on some practical aspects concerning diagnosis, differential diagnosis and treatment. Duplex ultrasound investigations are essential to ascertain the diagnosis of the underlying venous pathology and to treat venous refluxes. Differential diagnosis includes mainly other vascular lesions (arterial, microcirculatory causes), hematologic and metabolic diseases, trauma, infection, malignancies. Patients with superficial venous incompetence may benefit from endovenous or surgical reflux abolition diagnosed by Duplex ultrasound. The most important basic component of the management is compression therapy, for which we prefer materials with low elasticity applied with high initial pressure (short-stretch bandages and Velcro-strap devices). Local treatment should be simple, absorbing and not sticky dressings keeping adequate moisture balance after debridement of necrotic tissue and biofilms are preferred. After the ulcer is healed compression therapy should be continued in order to prevent recurrence. PMID:26236636

  7. PHYSIOLOGY OF ACID BASE BALANCE

    Directory of Open Access Journals (Sweden)

    Awati

    2014-12-01

    Full Text Available Acid-base, electrolyte, and metabolic disturbances are common in the intensive care unit. Almost all critically ill patients often suffer from compound acid-base and electrolyte disorders. Successful evaluation and management of such patients requires recognition of common patterns (e.g., metabolic acidosis and the ability to dissect one disorder from another. The intensivists needs to identify and correct these condition with the easiest available tools as they are the associated with multiorgan failure. Understanding the elements of normal physiology in these areas is very important so as to diagnose the pathological condition and take adequate measures as early as possible. Arterial blood gas analysis is one such tool for early detection of acid base disorder. Physiology of acid base is complex and here is the attempt to simplify it in our day to day application for the benefit of critically ill patients.

  8. Effects of Propanidid and Thiopentone on the Acid-Base Status of ...

    African Journals Online (AJOL)

    The effects of propanidid and thiopentone on the acidbase status of babies delivered by elective Caesarean section have been compared. The only significant difference between the 2 groups was the lower umbilical cord venous blood pCO) levels in the propanidid group. The acid-base status in both these groups of ...

  9. A Novel Stretch Sensor to Measure Venous Hemodynamics

    Directory of Open Access Journals (Sweden)

    Syrpailyne Wankhar

    2018-07-01

    Full Text Available Chronic venous insufficiency is a debilitating condition causing varicose veins and venous ulcers. The pathophysiology includes reflux and venous obstruction. The diagnosis is often made by clinical examination and confirmed by Venous Doppler studies. Plethysmography helps to quantitatively examine the reflux and diagnose the burden of deep venous pathology to better understand venous hemodynamics, which is not elicited by venous duplex examination alone. However, most of these tests are qualitative, expensive, and not easily available. In this paper, we demonstrate the potential use of a novel stretch sensor in the assessment of venous hemodynamics during different maneuvers by measuring the change in calf circumference. We designed the stretch sensor by using semiconductor strain gauges pasted onto a small metal bar to form a load cell. The elastic and Velcro material attached to the load cell form a belt. It converts the change in limb circumference to a proportional tension (force of distension when placed around the calf muscle. We recorded the change in limb circumference from arrays of stretch sensors by using an in-house data acquisition system. We calculated the venous volume (VV, venous filling index (VFI, ejection fraction (EF and residual venous volume (RVV on two normal subjects and on two patients to assess venous hemodynamics. The values (VV > 60 ml, VFI 60%, RVV 2ml/s, EF 35% in patients were comparable to those reported in the literature.

  10. Acid-base safety during the course of a very low-calorie-ketogenic diet

    OpenAIRE

    Gomez-Arbelaez, Diego; Crujeiras, Ana B.; Castro, Ana I.; Goday Arno, Alberto; Mas-Lorenzo, Antonio; Bellon, Ana; Tejera, Cristina; Bellido, Diego; Galban, Cristobal; Sajoux, Ignacio; Lopez-Jaramillo, Patricio; Casanueva, Felipe F.

    2017-01-01

    BACKGROUND AND AIMS: Very low-calorie ketogenic (VLCK) diets have been consistently shown to be an effective obesity treatment, but the current evidence for its acid-base safety is limited. The aim of the current work was to evaluate the acid-base status of obese patients during the course of a VLCK diet. METHOD: Twenty obese participants undertook a VLCK diet for 4 months. Anthropometric and biochemical parameters, and venous blood gases were obtained on four subsequent visits: visit C-1 (ba...

  11. Diagnosis of venous disorders

    International Nuclear Information System (INIS)

    Minar, E.

    1993-01-01

    Limited accuracy in the clinic diagnosis of deep vein thrombosis (VT) makes such diagnostic tests such as duplex sonography or venography necessary. Exact information on the age and extent of the thrombus are necessary for the clinician to optimize the therapeutric management. The correct diagnosis of calf vein thrombosis and of recurrent VT in patients with postphlebitis changes also has implications for treatment. After exclusion of thrombosis, the radiologist should evaluate the leg for other possible causes of symptoms besides VT. Investigation of the venous sytem also has a role in the diagnosis in patients with suspected pulmonary embolism. In patients with chronic venous insuffficiency the deep venous system should assessed for patency and venous valve function. The superficial veins should be differentiated in segments with sufficient or insufficient venous valves, and it is also necessary to look for insufficiency of the perforrating veins. In patients with superficial phlebitis there is risk of propagation into the deep venous system. (orig.) [de

  12. Cerebral venous angiomas

    International Nuclear Information System (INIS)

    Agnoli, A.L.; Hildebrandt, G.

    1985-01-01

    Clinical symptoms and radiological signs in 15 patients with cerebral venous malformations are presented and the diagnostic problems discussed. The circulation time in combination with cerebral malformations and angiomas of the scalp are described. CT findings in cases of venous malformations of the brain stem are evaluated. Spot-like enhancement, as well as sharply demarcated round shaped enhancement are characteristic for venous angiomas. Cavernous angiomas usually present as homogenous or inhomogenous round shaped enhanced areas. (Author)

  13. The Conjugate Acid-Base Chart.

    Science.gov (United States)

    Treptow, Richard S.

    1986-01-01

    Discusses the difficulties that beginning chemistry students have in understanding acid-base chemistry. Describes the use of conjugate acid-base charts in helping students visualize the conjugate relationship. Addresses chart construction, metal ions, buffers and pH titrations, and the organic functional groups and nonaqueous solvents. (TW)

  14. The Kidney and Acid-Base Regulation

    Science.gov (United States)

    Koeppen, Bruce M.

    2009-01-01

    Since the topic of the role of the kidneys in the regulation of acid base balance was last reviewed from a teaching perspective (Koeppen BM. Renal regulation of acid-base balance. Adv Physiol Educ 20: 132-141, 1998), our understanding of the specific membrane transporters involved in H+, HCO , and NH transport, and especially how these…

  15. Hydrogen converters

    International Nuclear Information System (INIS)

    Mondino, Angel V.

    2003-01-01

    The National Atomic Energy Commission of Argentina developed a process of 99 Mo production from fission, based on irradiation of uranium aluminide targets with thermal neutrons in the RA-3 reactor of the Ezeiza Atomic Centre. These targets are afterwards dissolved in an alkaline solution, with the consequent liberation of hydrogen as the main gaseous residue. This work deals with the use of a first model of metallic converter and a later prototype of glass converter at laboratory scale, adjusted to the requirements and conditions of the specific redox process. Oxidized copper wires were used, which were reduced to elementary copper at 400 C degrees and then regenerated by oxidation with hot air. Details of the bed structure and the operation conditions are also provided. The equipment required for the assembling in cells is minimal and, taking into account the operation final temperature and the purge with nitrogen, the procedure is totally safe. Finally, the results are extrapolated for the design of a converter to be used in a hot cell. (author)

  16. Chronic venous disorders

    African Journals Online (AJOL)

    The San Valentino Vascular Screening Project conducted in Italy found a ... developed healthcare systems, the cost of treating advanced venous disease ..... tissue inflammation and necrosis. Sclerosing ... and for its tributaries as an alternative.

  17. Prophylaxis of Venous Thrombosis.

    Science.gov (United States)

    Goldhaber, Samuel Z.

    2001-06-01

    Mechanical measures such as graduated compression stockings and intermittent compression boots are available for venous thrombosis prophylaxis, but compliance may be limited. Plantar venous pneumatic compression devices have attained widespread acceptance by both patients and nurses because of their comfort and compact size, but their track record for efficacy is poor. Inferior vena cava filters prevent pulmonary embolism, but do not halt the thrombotic process or prevent venous thrombosis. Pharmacologic prophylaxis traditionally has relied upon minidose unfractionated heparin; however, re-examination is warranted in the face of increasingly ill and complex patients. My opinion is that small, fixed doses of once-daily low molecular weight heparin will eventually replace minidose unfractionated heparin as the standard pharmacologic prophylaxis regimen for most surgical and medical patients. Prolongation of prophylaxis after hospital discharge should receive increased emphasis. Most patients being transferred to a skilled nursing facility should receive venous thromboembolism prophylaxis. Similarly, most patients undergoing total hip or knee replacement should receive prolonged preventive regimens, with at least 1 month of anticoagulation. Despite advances, certain aspects of venous thrombosis prophylaxis remain problematic. First, a surprisingly high number of hospitalized patients develop venous thrombosis because of failed (rather than omitted) prophylaxis. Second, many patients in intensive care have a combination of peripheral vascular disease and active bleeding (usually gastrointestinal) that precludes mechanical or pharmacologic prophylaxis. Third, neurosurgical patients undergoing craniotomy for brain tumors suffer a high rate of venous thrombosis and major pulmonary embolism despite the routine use of combined mechanical and pharmacologic prophylaxis. My opinion is that these three areas, in addition to the hospital culture of prophylaxis, should receive

  18. Ray converter

    International Nuclear Information System (INIS)

    Reiss, K.H.

    1976-01-01

    In a radiographic system a converter is used for changing image forming intensity distribution in a bundle of penetrating rays into a flow of electrically charged particles by electrodes located in a gas space and partly latticed (grids) which lie at potentials stepped from cathode to anode. The invention is particularly characterized by the provision of at least two grids extending between and parallel to the cathode and the anode. The electrical field which lies between two electrodes lies at least between the grids located closest to the cathode being to the extent of between 1 and 10 percent, in the average preferably 3 percent below the electrical break down field in the gas in a homogeneous electrical field

  19. History of Medical Understanding and Misunderstanding of Acid Base Balance

    Science.gov (United States)

    Aiken, Christopher Geoffrey Alexander

    2013-01-01

    To establish how controversies in understanding acid base balance arose, the literature on acid base balance was reviewed from 1909, when Henderson described how the neutral reaction of blood is determined by carbonic and organic acids being in equilibrium with an excess of mineral bases over mineral acids. From 1914 to 1930, Van Slyke and others established our acid base principles. They recognised that carbonic acid converts into bicarbonate all non-volatile mineral bases not bound by mineral acids and determined therefore that bicarbonate represents the alkaline reserve of the body and should be a physiological constant. They showed that standard bicarbonate is a good measure of acidosis caused by increased production or decreased elimination of organic acids. However, they recognised that bicarbonate improved low plasma bicarbonate but not high urine acid excretion in diabetic ketoacidosis, and that increasing pCO2 caused chloride to shift into cells raising plasma titratable alkali. Both indicate that minerals influence pH. In 1945 Darrow showed that hyperchloraemic metabolic acidosis in preterm infants fed milk with 5.7 mmol of chloride and 2.0 mmol of sodium per 100 kcal was caused by retention of chloride in excess of sodium. Similar findings were made but not recognised in later studies of metabolic acidosis in preterm infants. Shohl in 1921 and Kildeberg in 1978 presented the theory that carbonic and organic acids are neutralised by mineral base, where mineral base is the excess of mineral cations over anions and organic acid is the difference between mineral base, bicarbonate and protein anion. The degree of metabolic acidosis measured as base excess is determined by deviation in both mineral base and organic acid from normal. PMID:24179938

  20. Brain venous pathologies: MRI findings

    International Nuclear Information System (INIS)

    Salvatico, Rosana; Gonzalez, Alejandro; Yanez, Paulina; Romero, Carlos; Trejo, Mariano; Lambre, Hector

    2006-01-01

    Purpose: To describe MRI findings of the different brain venous pathologies. Material and Methods: Between January 2002 and March 2004, 18 patients were studied 10 males and 8 females between 6 and 63 years old; with different brain venous pathologies. In all cases brain MRI were performed including morphological sequences with and without gadolinium injection and angiographic venous sequences. Results: 10 venous occlusions were found, 6 venous angiomas, and 2 presented varices secondary to arteriovenous dural fistula. Conclusion: Brain venous pathologies can appear in many different clinical contexts, with different prognosis and treatment. In all the cases brain MRI was the best imaging study to disclose typical morphologic abnormalities. (author) [es

  1. Jigsaw Cooperative Learning: Acid-Base Theories

    Science.gov (United States)

    Tarhan, Leman; Sesen, Burcin Acar

    2012-01-01

    This study focused on investigating the effectiveness of jigsaw cooperative learning instruction on first-year undergraduates' understanding of acid-base theories. Undergraduates' opinions about jigsaw cooperative learning instruction were also investigated. The participants of this study were 38 first-year undergraduates in chemistry education…

  2. Cerebral venous thrombosis

    International Nuclear Information System (INIS)

    Soralova, T.; Sevcikova, H.; Petersky, D.

    2014-01-01

    We decided to process this theme due to its nonspecific clinical features as they often cause diagnostic problems not only to clinicians but also to diagnostic. It is important to think of this disease mainly in young women who administer hormonal contraception. Imaging methods play the crucial role in diagnostic of cerebral venous sinus thrombosis. The gold standard is a native CT of brain which shows the venous sinus thrombosis as a hyperdense lesion in the locus of the sinus (dense triangle sign), CT venography shows the sinus thrombosis as a defect in a contrast filling of the venous sinus (empty delta sign). Other investigative methods are magnetic resonance imaging or MRA. In short we also mention quite a rare but more serious thrombosis of profound cerebral veins v. cerebri magna-Galeni, vv. cerebri internae). The importance of early diagnostic and non specificity of symptoms is presented in 3 clinical cases that are the part of this work. (author)

  3. Direct venous thrombolysis and venous angioplasty in the upper extremity

    International Nuclear Information System (INIS)

    Hollmann, J.P.; Guenther, R.W.

    1987-01-01

    Venous thromboses of stenoses in the upper extremity are often the result of a compression syndrome of the shoulder girdle, the Paget-von Schroetter syndrome, vascular surgery, space-occupying lesions in the mediastinum or the result of catheterisation. Direct venous thrombolysis and venous angioplasty were performed successfully in six patients. (orig.) [de

  4. Chronic venous disease.

    Science.gov (United States)

    Wolinsky, Claire D; Waldorf, Heidi

    2009-11-01

    Identifying characteristic cutaneous findings is important in determining the appropriate management of certain venous diseases. The health care provider should be familiar with the classic description of patterns and distributions of skin manifestations, such as varicose veins, stasis dermatitis, palpable cord, petechiae, and telangiectasias. In addition to the gross appearance of the skin, a skin biopsy may help elucidate a diagnosis. General treatment and prevention of the underlying venous pathology is essential. Furthermore, specific management of skin findings should include therapy to ameliorate progression of disease and symptomatology when warranted.

  5. Central Venous Access

    International Nuclear Information System (INIS)

    Ganeshan, Arul; Warakaulle, Dinuke R.; Uberoi, Raman

    2007-01-01

    Central venous access plays an important role in the management of an ever-increasing population of patients ranging from those that are critically ill to patients with difficult clinical access. Interventional radiologists are key in delivering this service and should be familiar with the wide range of techniques and catheters now available to them. A comprehensive description of these catheters with regard to indications, technical aspects of catheterization, success rates, and associated early and late complications, as well as a review of various published guidelines on central venous catheter insertion are given in this article

  6. Venous ulcers -- self-care

    Science.gov (United States)

    ... surgery to improve blood flow through your veins. Prevention If you are at risk for venous ulcers, take the steps listed above under Wound Care. ... weight if you are overweight. Manage your blood pressure and cholesterol levels. ... Venous leg ulcers - self-care; Venous insufficiency ulcers - self-care; Stasis ...

  7. Acid-base properties of ceramic powders

    International Nuclear Information System (INIS)

    Bleier, A.

    1983-01-01

    This chapter addresses the fundamental aspects of potentiometric titration, electrokinetics, and conductometric titration in evaluating surface and interfacial thermodynamic behavior. Emphasizes the characterization of aqueous systems which are pertinent to the processing of ceramic powders. Attempts to clarify the role of novel analytical techniques that will increasingly contribute to the advanced characterization of ceramic powders. Evaluates recently developed acid-base and complexation concepts and their applications to the processing of oxide ceramics

  8. DISORDERS OF ACID-BASE STATE

    OpenAIRE

    P. F. Litvitskiy

    2011-01-01

    The lecture describes modern data on disorders of acid-base state (ABS): their types, etiology, key stages of pathogenesis, main symptoms, and principles of treatment. The first part of the lecture in present journal characterizes main conception, parameters of ABS in normal state, buffer systems, common mechanisms of BS shifts elimination, etiology and pathogenesis of gas-induced (respiratory) disorders of ABS. The second part of the lecture in following journal will describe not gas-induced...

  9. Cerebral venous angioma

    International Nuclear Information System (INIS)

    Inagawa, Tetsuji; Taguchi, Haruyoshi; Kamiya, Kazuko; Yano, Takashi; Nakajima, Reiko

    1984-01-01

    This report presents a 27-year-old male patient who was diagnosed as having cerebral venous angioma in the postero-temporal area by CT scan and cerebral angiography. The patient improved by removing angioma with electrocoagulation of medullary veins. (Namekawa, K.)

  10. Whole body acid-base modeling revisited.

    Science.gov (United States)

    Ring, Troels; Nielsen, Søren

    2017-04-01

    The textbook account of whole body acid-base balance in terms of endogenous acid production, renal net acid excretion, and gastrointestinal alkali absorption, which is the only comprehensive model around, has never been applied in clinical practice or been formally validated. To improve understanding of acid-base modeling, we managed to write up this conventional model as an expression solely on urine chemistry. Renal net acid excretion and endogenous acid production were already formulated in terms of urine chemistry, and we could from the literature also see gastrointestinal alkali absorption in terms of urine excretions. With a few assumptions it was possible to see that this expression of net acid balance was arithmetically identical to minus urine charge, whereby under the development of acidosis, urine was predicted to acquire a net negative charge. The literature already mentions unexplained negative urine charges so we scrutinized a series of seminal papers and confirmed empirically the theoretical prediction that observed urine charge did acquire negative charge as acidosis developed. Hence, we can conclude that the conventional model is problematic since it predicts what is physiologically impossible. Therefore, we need a new model for whole body acid-base balance, which does not have impossible implications. Furthermore, new experimental studies are needed to account for charge imbalance in urine under development of acidosis. Copyright © 2017 the American Physiological Society.

  11. [Deeper understanding of fetal acid-base equilibrium].

    Science.gov (United States)

    Roemer, V M

    1993-01-01

    variables of the fetal acid-base-balance is demonstrated in 738 newborns sharing Apgar-scores of 8 after one minute. The diagnostic potential of acid-base-variables in UV-blood as a mirror of placental function is outlined.

  12. Models of the venous system

    DEFF Research Database (Denmark)

    Mehlsen, J

    2000-01-01

    Cardiac output is largely controlled by venous return, the driving force of which is the energy remaining at the postcapillary venous site. This force is influenced by forces acting close to the right atrium, and internally or externally upon the veins along their course. Analogue models of the v......Cardiac output is largely controlled by venous return, the driving force of which is the energy remaining at the postcapillary venous site. This force is influenced by forces acting close to the right atrium, and internally or externally upon the veins along their course. Analogue models...... of the venous system require at least three elements: a resistor, a capacitor and an inductor, with the latter being of more importance in the venous than in the arterial system. Non-linearities must be considered in pressure/flow relations in the small venules, during venous collapse, or low flow conditions...

  13. Correlation between arterial blood gas analysis and peripheral blood gas analysis in acid-base unbalance state

    Directory of Open Access Journals (Sweden)

    Hyun Lee Kim

    2012-06-01

    Full Text Available Acid-base unbalance is most common problem in severe ill patient, especially in condition of abnormal renal function state. Acid-base unbalances are respiratory acidosis, respiratory alkalosis, metabolic acidosis, and metabolic alkalosis. Metabolic acidosis is frequently appeared in clinical state. Arterial blood gas analysis is considered as a basic test to the intensive care unit patient and emergency state. Recently some researches were done, comparing with arterial blood gas analysis and venous blood gas analysis. Because of venous blood sampling is safer than arterial blood gas analysis, and beside not so different among them for detecting pH, pCO2, HCO3, except pO2 measuring. This research was done in emergency room, and for explaining no different between arterial blood gas analysis and peripheral blood gas analysis result in acid-base unbalance state patient. Especially in kidney functions decreased state. : The study was done from March, 2010 to January, 2011. The object was 89 peoples who came to emergency room for treating internal medicine problem. (Women 53, average age: 66.7±12.1 Then compare between arterial blood gas analysis and peripheral blood gas analysis. Result: The mean arterial minus venous difference for pH, pCO2, and bicarbonate was −0.0170, 2.6528, and 0.6124. Bland-Altman plot was done for predicting agreement of two groups, and the scale was pH −2.95 to 4.17, pCO2 −4.45 to 9.76, bicarbonate −2.95 to 4.16, in 95% relative. Conclusion: The peripheral blood gas pH, pCO2, bicarbonate level is almost same as arterial blood gas analysis results. And enough to measuring acid-base unbalance state, in absent of arterial blood testing.

  14. Mathematical modeling of acid-base physiology.

    Science.gov (United States)

    Occhipinti, Rossana; Boron, Walter F

    2015-01-01

    pH is one of the most important parameters in life, influencing virtually every biological process at the cellular, tissue, and whole-body level. Thus, for cells, it is critical to regulate intracellular pH (pHi) and, for multicellular organisms, to regulate extracellular pH (pHo). pHi regulation depends on the opposing actions of plasma-membrane transporters that tend to increase pHi, and others that tend to decrease pHi. In addition, passive fluxes of uncharged species (e.g., CO2, NH3) and charged species (e.g., HCO3(-), [Formula: see text] ) perturb pHi. These movements not only influence one another, but also perturb the equilibria of a multitude of intracellular and extracellular buffers. Thus, even at the level of a single cell, perturbations in acid-base reactions, diffusion, and transport are so complex that it is impossible to understand them without a quantitative model. Here we summarize some mathematical models developed to shed light onto the complex interconnected events triggered by acids-base movements. We then describe a mathematical model of a spherical cells-which to our knowledge is the first one capable of handling a multitude of buffer reactions-that our team has recently developed to simulate changes in pHi and pHo caused by movements of acid-base equivalents across the plasma membrane of a Xenopus oocyte. Finally, we extend our work to a consideration of the effects of simultaneous CO2 and HCO3(-) influx into a cell, and envision how future models might extend to other cell types (e.g., erythrocytes) or tissues (e.g., renal proximal-tubule epithelium) important for whole-body pH homeostasis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. The acid/base profile of agrochemicals.

    Science.gov (United States)

    Manallack, D T

    2017-08-01

    Drug-likeness has long been studied in the pursuit of finding new medicines. Similarly, in the agrochemical field there is value in exploring the properties of the chemicals involved. Patterns that emerge can potentially influence future discovery campaigns to improve the probability of commercial success. In this study we investigate the acid/base properties and physicochemical characteristics of three classes of compounds: fungicides, herbicides and insecticides. In comparison with FDA-approved drugs, it was noted that the pesticides were generally smaller, possessed a neutral charge state and were more lipophilic. The results are discussed in the light of their intended targets.

  16. DISORDERS OF ACID-BASE STATE

    Directory of Open Access Journals (Sweden)

    P. F. Litvitskiy

    2011-01-01

    Full Text Available The lecture describes modern data on disorders of acid-base state (ABS: their types, etiology, key stages of pathogenesis, main symptoms, and principles of treatment. The first part of the lecture in present journal characterizes main conception, parameters of ABS in normal state, buffer systems, common mechanisms of BS shifts elimination, etiology and pathogenesis of gas-induced (respiratory disorders of ABS. The second part of the lecture in following journal will describe not gas-induced (metabolic, excretory and exogenous disorders of ABS and principles of their treatment.

  17. Metabolic Effects of a Succinic Acid Substrate Antihypoxant

    Directory of Open Access Journals (Sweden)

    B. N. Shakh

    2014-01-01

    Full Text Available The paper discusses promises for clinical use of substrate antihypoxants.Objective: to investigate the efficacy of succinate containing  substrate  antihypoxants  on  systemic  oxygen  consumption,  blood  buffer  capacity,  and  changes  in  the  mixed venous blood level of lactate when they are used in gravely sick patients and victims with marked metabolic posthypoxic disorders.Subjects and methods. The trial enrolled 30 patients and victims who had sustained an episode of severe hypoxia of mixed genesis, the severity of which was evaluated by the APACHE II scale and amounted to 23 to 30 scores with a 46 to 70.3% risk of death. The standard infusion program in this group involved the succinate-containing drug 1.5% reamberin solution  in  a  total  dose  of  800  ml.  A  comparison  group  included  15  patients  who  had  undergone  emergency  extensive surgery for abdominal diseases. 400 ml of 10% glucose solution was used as an infusion medium. Oxygen consumption (VO2ml/min and carbon dioxide production (VCO2ml/min were measured before infusion and monitored for 2 hours. Arterial blood gases and acid-base balance (ABB parameters and mixed venous blood lactate levels were examined. Measurements were made before and 30 minutes after the infusion of reamberin or glucose solution.Results. Infusion of 1.5% reamberin solution was followed by a significant increase in minute oxygen consumption from 281.5±21.2 to 310.4±24.4 ml/min. CO2 production declined (on average, from 223.3±6.5 to 206.5±7.59 ml/min. During infusion of 10% glucose solution, all the patients of the comparison group showed a rise in oxygen consumption from 303.6±33.86 to 443.13±32.1 ml/min, i.e. about 1.5-fold. VCO2 changed similarly. The intravenous infusion of 800 ml of 1.5% reamberin solution raised arterial blood buffer capacity, which was reflected by changes in pH, BE, and HCO3. There was a clear trend for lactate values to drop in the

  18. Investigating Students' Reasoning about Acid-Base Reactions

    Science.gov (United States)

    Cooper, Melanie M.; Kouyoumdjian, Hovig; Underwood, Sonia M.

    2016-01-01

    Acid-base chemistry is central to a wide range of reactions. If students are able to understand how and why acid-base reactions occur, it should provide a basis for reasoning about a host of other reactions. Here, we report the development of a method to characterize student reasoning about acid-base reactions based on their description of…

  19. A General Simulator for Acid-Base Titrations

    Science.gov (United States)

    de Levie, Robert

    1999-07-01

    General formal expressions are provided to facilitate the automatic computer calculation of acid-base titration curves of arbitrary mixtures of acids, bases, and salts, without and with activity corrections based on the Davies equation. Explicit relations are also given for the buffer strength of mixtures of acids, bases, and salts.

  20. Teaching Acid/Base Physiology in the Laboratory

    Science.gov (United States)

    Friis, Ulla G.; Plovsing, Ronni; Hansen, Klaus; Laursen, Bent G.; Wallstedt, Birgitta

    2010-01-01

    Acid/base homeostasis is one of the most difficult subdisciplines of physiology for medical students to master. A different approach, where theory and practice are linked, might help students develop a deeper understanding of acid/base homeostasis. We therefore set out to develop a laboratory exercise in acid/base physiology that would provide…

  1. Assessing College Students' Understanding of Acid Base Chemistry Concepts

    Science.gov (United States)

    Wan, Yanjun Jean

    2014-01-01

    Typically most college curricula include three acid base models: Arrhenius', Bronsted-Lowry's, and Lewis'. Although Lewis' acid base model is generally thought to be the most sophisticated among these three models, and can be further applied in reaction mechanisms, most general chemistry curricula either do not include Lewis' acid base model, or…

  2. Using Willie's Acid-Base Box for Blood Gas Analysis

    Science.gov (United States)

    Dietz, John R.

    2011-01-01

    In this article, the author describes a method developed by Dr. William T. Lipscomb for teaching blood gas analysis of acid-base status and provides three examples using Willie's acid-base box. Willie's acid-base box is constructed using three of the parameters of standard arterial blood gas analysis: (1) pH; (2) bicarbonate; and (3) CO[subscript…

  3. Medical management of venous ulcers.

    Science.gov (United States)

    Pascarella, Luigi; Shortell, Cynthia K

    2015-03-01

    Venous disease is the most common cause of chronic leg ulceration and represents an advanced clinical manifestation of venous insufficiency. Due to their frequency and chronicity, venous ulcers have a high socioeconomic impact, with treatment costs accounting for 1% of the health care budget in Western countries. The evaluation of patients with venous ulcers should include a thorough medical history for prior deep venous thrombosis, assessment for an hypercoagulable state, and a physical examination. Use of the CEAP (clinical, etiology, anatomy, pathophysiology) Classification System and the revised Venous Clinical Severity Scoring System is strongly recommended to characterize disease severity and assess response to treatment. This venous condition requires lifestyle modification, with affected individuals performing daily intervals of leg elevation to control edema; use of elastic compression garments; and moderate physical activity, such as walking wearing below-knee elastic stockings. Meticulous skin care, treatment of dermatitis, and prompt treatment of cellulitis are important aspects of medical management. The pharmacology of chronic venous insufficiency and venous ulcers include essentially two medications: pentoxifylline and phlebotropic agents. The micronized purified flavonoid fraction is an effective adjunct to compression therapy in patients with large, chronic ulceration. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. [Acid-base equilibrium and the brain].

    Science.gov (United States)

    Rabary, O; Boussofara, M; Grimaud, D

    1994-01-01

    In physiological conditions, the regulation of acid-base balance in brain maintains a noteworthy stability of cerebral pH. During systemic metabolic acid-base imbalances cerebral pH is well controlled as the blood/brain barrier is slowly and poorly permeable to electrolytes (HCO3- and H+). Cerebral pH is regulated by a modulation of the respiratory drive, triggered by the early alterations of interstitial fluid pH, close to medullary chemoreceptors. As blood/brain barrier is highly permeable to Co2, CSF pH is corrected in a few hours, even in case of severe metabolic acidosis and alkalosis. Conversely, during ventilatory acidosis and alkalosis the cerebral pH varies in the same direction and in the same range than blood pH. Therefore, the brain is better protected against metabolic than ventilatory acid-base imbalances. Ventilatory acidosis and alkalosis are able to impair cerebral blood flow and brain activity through interstitial pH alterations. During respiratory acidosis, [HCO3-] increases in extracellular fluids to control cerebral pH by two main ways: a carbonic anhydrase activation at the blood/brain and blood/CSF barriers level and an increase in chloride shift in glial cells (HCO3- exchanged for Cl-). During respiratory alkalosis, [HCO3-] decreases in extracellular fluids by the opposite changes in HCO3- transport and by an increase in lactic acid synthesis by cerebral cells. The treatment of metabolic acidosis with bicarbonates may induce a cerebral acidosis and worsen a cerebral oedema during ketoacidosis. Moderate hypocapnia carried out to treat intracranial hypertension is mainly effective when cerebral blood flow is high and vascular CO2 reactivity maintained. Hypocapnia may restore an altered cerebral blood flow autoregulation. Instrumental hypocapnia requires a control of cerebral perfusion pressure and cerebral arteriovenous difference for oxygen, to select patients for whom this kind of treatment may be of benefit, to choose the optimal level of

  5. Physiological roles of acid-base sensors.

    Science.gov (United States)

    Levin, Lonny R; Buck, Jochen

    2015-01-01

    Acid-base homeostasis is essential for life. The macromolecules upon which living organisms depend are sensitive to pH changes, and physiological systems use the equilibrium between carbon dioxide, bicarbonate, and protons to buffer their pH. Biological processes and environmental insults are constantly challenging an organism's pH; therefore, to maintain a consistent and proper pH, organisms need sensors that measure pH and that elicit appropriate responses. Mammals use multiple sensors for measuring both intracellular and extracellular pH, and although some mammalian pH sensors directly measure protons, it has recently become apparent that many pH-sensing systems measure pH via bicarbonate-sensing soluble adenylyl cyclase.

  6. Management of venous thromboembolism.

    Science.gov (United States)

    Parakh, R; Kakkar, V V; Kakkar, A K

    2007-01-01

    Venous Thromboembolism is an important healthcare problem the world over, resulting in significant morbidity, mortality and resource expenditure. The rationale for use of thromboprophylaxis is based on solid principles and scientific evidence. Indian perspective on this topic is lacking due to the non-availability of published Indian data. This document reviews the available International and Indian data and discusses the relevance of recommendations for prevention and management of Venous Thromboembolism (VTE) in the Indian context. Meetings of various specialists from different Indian hospitals in the field of Gastrointestinal Surgery, General and Vascular Surgery, Hematology, Intensive Care, Obstetrics and Gynecology, Oncology and Orthopedics were held in the months of August 2005 to January 2006. The guidelines published by American College of Chest Physicians (ACCP), the International Union of Angiology (IUA), and the Royal College of Obstetricians and Gynecologists (RCOG), were discussed during these meetings. The relevance of these guidelines and the practical implications of following these in a developing country like India were also discussed. Any published data from India was collected from data base searches and the results, along with personal experiences of the participating specialists were discussed. The experiences and impressions of the experts during these meetings have been included in this document. Data from recent sources (International Union of Angiology and the National Comprehensive Cancer Network (NCCN) Practice guidelines in Oncology on Venous thromboembolic disease) was subsequently also included in this document. The suggestions formulated in this document are practical, and would intend to serve as a useful practical reference. A number of unanswered questions remain in the field of thromboprophylaxis, and carefully designed research protocols may help answer some of these. Implementation of the suggestions outlined in the document

  7. Venous leg ulcers

    Science.gov (United States)

    2008-01-01

    Introduction Leg ulcers usually occur secondary to venous reflux or obstruction, but 20% of people with leg ulcers have arterial disease, with or without venous disorders. Between 1.5 and 3.0/1000 people have active leg ulcers. Prevalence increases with age to about 20/1000 in people aged over 80 years. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of standard treatments, adjuvant treatments, and organisational interventions for venous leg ulcers? What are the effects of interventions to prevent recurrence of venous leg ulcers? We searched: Medline, Embase, The Cochrane Library, and other important databases up to September 2007 (BMJ Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 80 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: compression bandages and stockings, cultured allogenic (single or bilayer) skin replacement, debriding agents, dressings (cellulose, collagen, film, foam, hyaluronic acid-derived, semi-occlusive alginate), hydrocolloid (occlusive) dressings in the presence of compression, intermittent pneumatic compression, intravenous prostaglandin E1, larval therapy, laser treatment (low-level), leg ulcer clinics, multilayer elastic system, multilayer elastomeric (or non-elastomeric) high-compression regimens or bandages, oral treatments (aspirin, flavonoids, pentoxifylline, rutosides, stanozolol, sulodexide, thromboxane alpha2 antagonists, zinc), peri

  8. Acid base imbalances in ill neonatal foals and their association with survival.

    Science.gov (United States)

    Viu, J; Armengou, L; Ríos, J; Cesarini, C; Jose-Cunilleras, E

    2017-01-01

    Acid-base imbalances observed in human paediatric patients are associated with outcome. Likewise, neonatal foals may have different acid-base imbalances associated with diagnosis or prognosis. To determine acid-base imbalances by the quantitative method in ill neonatal foals and assess their association with diagnosis and prognosis. Observational prospective clinical study. This study included 65 ill neonatal foals (32 septic, 33 nonseptic) admitted to an equine referral hospital from 2005 to 2011with acid-base parameters determined on admission and a control group of 33 healthy neonatal foals. Blood pH, pCO 2 , sodium, potassium, chloride, L-lactate, albumin and phosphate concentrations were determined. Bicarbonate, globulin, measured strong ion difference (SID m ), nonvolatile weak buffer concentrations (A tot ), base excess and its components were calculated. Analysis of covariance (ANCOVA) and multiple linear regression statistical analyses were performed. Results are summarised as mean ± s.d. for normally distributed variables and median [25-75th percentiles] for non-normally distributed ones. A total of 63% of ill foals had respiratory alkalosis and 58.5% had SID m acidosis. The combination of both alterations was detected in 21 of 65 ill foals and abnormal pH was found in 24 of 65. Compared with healthy foals, ill foals had significantly lower SID m (nonseptic 31.6 ± 6.3 [Pacid-base imbalances observed in ill foals were respiratory alkalosis, SID m acidosis or mixed respiratory alkalosis with strong ion acidosis. Increased venous pCO 2 and blood L-lactate concentration were associated with poor outcome. © 2015 EVJ Ltd.

  9. Chronic Venous Disease under pressure

    NARCIS (Netherlands)

    S.W.I. Reeder (Suzan)

    2013-01-01

    textabstractIn chapter 1 we provide a general introduction of this thesis. Chronic venous disease (CVD) is a common medical condition that affects 2-64% of the worldwide population and leads to leg ulcers in 1% of the Western population. Venous leg ulceration (VLU) has an unfavorable prognosis with

  10. Bicarbonate Concentration, Acid-Base Status, and Mortality in the Health, Aging, and Body Composition Study.

    Science.gov (United States)

    Raphael, Kalani L; Murphy, Rachel A; Shlipak, Michael G; Satterfield, Suzanne; Huston, Hunter K; Sebastian, Anthony; Sellmeyer, Deborah E; Patel, Kushang V; Newman, Anne B; Sarnak, Mark J; Ix, Joachim H; Fried, Linda F

    2016-02-05

    Low serum bicarbonate associates with mortality in CKD. This study investigated the associations of bicarbonate and acid-base status with mortality in healthy older individuals. We analyzed data from the Health, Aging, and Body Composition Study, a prospective study of well functioning black and white adults ages 70-79 years old from 1997. Participants with arterialized venous blood gas measurements (n=2287) were grouped into respiratory alkalosis, and 1.35 (95% CI, 1.08 to 1.69) for metabolic alkalosis categories. Respiratory acidosis did not associate with mortality. In generally healthy older individuals, low serum bicarbonate associated with higher mortality independent of systemic pH and potential confounders. This association seemed to be present regardless of whether the cause of low bicarbonate was metabolic acidosis or respiratory alkalosis. Metabolic alkalosis also associated with higher mortality. Copyright © 2016 by the American Society of Nephrology.

  11. Technologies for converter topologies

    Science.gov (United States)

    Zhou, Yan; Zhang, Haiyu

    2017-02-28

    In some embodiments of the disclosed inverter topologies, an inverter may include a full bridge LLC resonant converter, a first boost converter, and a second boost converter. In such embodiments, the first and second boost converters operate in an interleaved manner. In other disclosed embodiments, the inverter may include a half-bridge inverter circuit, a resonant circuit, a capacitor divider circuit, and a transformer.

  12. Wavelength converter technology

    DEFF Research Database (Denmark)

    Kloch, Allan; Hansen, Peter Bukhave; Poulsen, Henrik Nørskov

    1999-01-01

    Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on all-optical wavelength converter types based on semiconductor optical amplifiers.......Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on all-optical wavelength converter types based on semiconductor optical amplifiers....

  13. Venous thromboembolism in women

    DEFF Research Database (Denmark)

    Group, ESHRE Capri Workshop; Skouby, Sven Olaf

    2013-01-01

    BACKGROUND Venous thromboembolism (VTE) is a specific reproductive health risk for women. METHODS Searches were performed in Medline and other databases. The selection criteria were high-quality studies and studies relevant to clinical reproductive medicine. Summaries were presented and discussed...... is associated with an inherited thrombophilia in men and women. Changes in the coagulation system and in the risk of clinical VTE in women also occur during pregnancy, with the use of reproductive hormones and as a consequence of ovarian stimulation when hyperstimulation syndrome and conception occur together...... therapy (HRT) increases the VTE risk 2- to 4-fold. There is a synergistic effect between thrombophilia and the various reproductive risks. Prevention of VTE during pregnancy should be offered to women with specific risk factors. In women who are at high risk, CHC and HRT should be avoided. CONCLUSIONS...

  14. Acid-base status and changes in Swedish forest soils

    International Nuclear Information System (INIS)

    Karltun, Erik; Stendahl, Johan; Lundin, Lars

    2003-01-01

    In this paper we use data from the Swedish National Survey of Forest Soils and Vegetation (NSFSV) to evaluate the present acid-base status of forest soils to try to answer the following questions. Which role do anthropogenic and biological acidification play for the present acid-base status of the soil profile? What is the present acid-base status of Swedish forest soils and how large areas may be considered as severely acidified? Do the current tendencies in soil acid-base status correspond with the positive development in surface waters?

  15. Venous hemodynamic changes in lower limb venous disease

    DEFF Research Database (Denmark)

    Lee, Byung Boong; Nicolaides, Andrew N; Myers, Kenneth

    2016-01-01

    ). Their aim was to confirm or dispel long-held hemodynamic principles and to provide a comprehensive review of venous hemodynamic concepts underlying the pathophysiology of lower limb venous disorders, their usefulness for investigating patients and the relevant hemodynamic changes associated with various...... forms of treatment. Chapter 1 is devoted to basic hemodynamic concepts and normal venous physiology. Chapter 2 presents the mechanism and magnitude of hemodynamic changes in acute deep vein thrombosis indicating their pathophysiological and clinical significance. Chapter 3 describes the hemodynamic...... changes that occur in different classes of chronic venous disease and their relation to the anatomic extent of disease in the macrocirculation and microcirculation. The next four chapters (Chapters 4-7) describe the hemodynamic changes resulting from treatment by compression using different materials...

  16. Acid-base changes in canine neonates following normal birth or dystocia.

    Science.gov (United States)

    Lúcio, C F; Silva, L C G; Rodrigues, J A; Veiga, G A L; Vannucchi, C I

    2009-07-01

    There are limited data concerning blood gas parameters in neonatal dogs. Knowledge of the normal physiology may facilitate effective therapeutic intervention and potentially reduce neonatal mortality. This study examined acid-base parameters in pups born at normal parturition (n = 27) compared with those born after obstetrical assistance or caesarean operation (n = 13) and those born following oxytocin (OXY) administration for treatment of uterine inertia (n = 11). Pups were subjected to an objective scoring method of neonatal health adapted from use in humans (the Apgar score) at birth and again at 5 and 60 min after birth. Venous blood samples were collected at 5 and 60 min after birth for evaluation of blood gas parameters. At birth, all pups had low Apgar scores and a mixed acidosis. The base excess was lowest for pups delivered after OXY administration. The Apgar score improved for all pups after 5 min of birth and there was an improvement in carbon dioxide tension, base excess and venous blood pH at 1 h, although in all pups a metabolic acidosis persisted. These data provide an important insight into neonatal physiology and the variability of blood gas parameters in pups born at normal and abnormal parturition and provide the basis for clinical decision making following dystocia.

  17. Hydrocephalus in cerebral venous thrombosis

    NARCIS (Netherlands)

    Zuurbier, Susanna M.; van den Berg, René; Troost, Dirk; Majoie, Charles B.; Stam, Jan; Coutinho, Jonathan M.

    2015-01-01

    Increased intracranial pressure is common in cerebral venous thrombosis (CVT), but hydrocephalus is rarely reported in these patients. We examined the frequency, pathophysiology and associated clinical manifestations of hydrocephalus in patients with CVT admitted to our hospital between 2000 and

  18. Venous thromboembolism and arterial complications.

    Science.gov (United States)

    Prandoni, Paolo; Piovella, Chiara; Pesavento, Raffaele

    2012-04-01

    An increasing body of evidence suggests the likelihood of a link between venous and arterial thrombosis. The two vascular complications share several risk factors, such as age, obesity, smoking, diabetes mellitus, blood hypertension, hypertriglyceridemia, and metabolic syndrome. Moreover, there are many examples of conditions accounting for both venous and arterial thrombosis, such as the antiphospholipid antibody syndrome, hyperhomocysteinemia, malignancies, infections, and the use of hormonal treatment. Finally, several recent studies have consistently shown that patients with venous thromboembolism are at a higher risk of arterial thrombotic complications than matched control individuals. We, therefore, speculate the two vascular complications are simultaneously triggered by biological stimuli responsible for activating coagulation and inflammatory pathways in both the arterial and the venous system. Future studies are needed to clarify the nature of this association, to assess its extent, and to evaluate its implications for clinical practice. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  19. Total anomalous pulmonary venous return

    Science.gov (United States)

    ... pulmonary venous return, x-ray References Fraser CD, Kane LC. Congenital heart disease. In: Townsend CM Jr, ... 62. Review Date 10/17/2017 Updated by: Michael A. Chen, MD, PhD, Associate Professor of Medicine, ...

  20. A Closer Look at Acid-Base Olfactory Titrations

    Science.gov (United States)

    Neppel, Kerry; Oliver-Hoyo, Maria T.; Queen, Connie; Reed, Nicole

    2005-01-01

    Olfactory titrations using raw onions and eugenol as acid-base indicators are reported. An in-depth investigation on olfactory titrations is presented to include requirements for potential olfactory indicators and protocols for using garlic, onions, and vanillin as acid-base olfactory indicators are tested.

  1. Improving venous leg ulcer management

    OpenAIRE

    Weller, Carolina Dragica

    2017-01-01

    This thesis reports several different methods to develop and evaluate complex interventions designed to improve venous leg ulcer management. Chronic venous leg ulcers (VLU) are the most common chronic wound problem in the community. Its health and economic burden is predicted to increase due to ageing of the community and increase in prevalence of diabetes and obesity. Although many patients seek health care for VLU, most do not receive the most effective management. Patients with this condi...

  2. A comparison of traditional and quantitative analysis of acid-base imbalances in hypoalbuminemic dogs.

    Science.gov (United States)

    Torrente, Carlos; Manzanilla, Edgar G; de Gopegui, Rafael Ruiz

    2014-01-01

    To compare the traditional (HH) and quantitative approaches used for the evaluation of the acid-base balance in hypoalbuminemic dogs. Prospective observational study. ICU of a veterinary teaching hospital. One hundred and five client-owned dogs. Jugular venous blood samples were collected from each patient on admission to determine: total plasma protein (TP), albumin (Alb), blood urea nitrogen (BUN), glucose (Glu), hematocrit (HCT), Na(+) , Cl(-) , K(+) , phosphate (Pi ), pH, PvCO2, bicarbonate (HCO3 (-) ), anion gap (AG), adjusted anion gap for albumin (AGalb ) or phosphate (AGalb-phos ), standardized base excess (SBE), strong ion difference (SID), concentration of nonvolatile weak buffers (Atot ), and strong ion gap (SIG). Patients were divided in 2 groups according to the severity of the hypoalbuminemia: mild (Alb = 21-25 g/L) and severe (Alb ≤20 g/L). All parameters were compared among groups. Patients with severe hypoalbuminemia showed significant decrease in TP (P = 0.011), Atot (P = 0.050), and a significant increase in adjusted AG (P = 0.048) and the magnitude of SIG (P = 0.011) compared to animals with mild hypoalbuminemia. According to the HH approach, the most frequent imbalances were simple disorders (51.4%), primarily metabolic acidosis (84.7%) associated with a high AG acidosis. However, when using the quantitative method, 58.1% of patients had complex disorders, with SIG acidosis (74.3%) and Atot alkalosis (33.3%) as the most frequent acid-base imbalances. Agreement between methods only matched in 32 cases (kappa acid-base balance was poor and many imbalances detected using the quantitative approach were missed using the HH approach. Further studies are necessary to confirm the clinical utility of using the quantitative approach in the decision-making process of the severely ill hypoalbuminemic patients. © Veterinary Emergency and Critical Care Society 2014.

  3. Combined oral contraceptives: venous thrombosis.

    Science.gov (United States)

    de Bastos, Marcos; Stegeman, Bernardine H; Rosendaal, Frits R; Van Hylckama Vlieg, Astrid; Helmerhorst, Frans M; Stijnen, Theo; Dekkers, Olaf M

    2014-03-03

    Combined oral contraceptive (COC) use has been associated with venous thrombosis (VT) (i.e., deep venous thrombosis and pulmonary embolism). The VT risk has been evaluated for many estrogen doses and progestagen types contained in COC but no comprehensive comparison involving commonly used COC is available. To provide a comprehensive overview of the risk of venous thrombosis in women using different combined oral contraceptives. Electronic databases (Pubmed, Embase, Web of Science, Cochrane, CINAHL, Academic Search Premier and ScienceDirect) were searched in 22 April 2013 for eligible studies, without language restrictions. We selected studies including healthy women taking COC with VT as outcome. The primary outcome of interest was a fatal or non-fatal first event of venous thrombosis with the main focus on deep venous thrombosis or pulmonary embolism. Publications with at least 10 events in total were eligible. The network meta-analysis was performed using an extension of frequentist random effects models for mixed multiple treatment comparisons. Unadjusted relative risks with 95% confidence intervals were reported.Two independent reviewers extracted data from selected studies. 3110 publications were retrieved through a search strategy; 25 publications reporting on 26 studies were included. Incidence of venous thrombosis in non-users from two included cohorts was 0.19 and 0.37 per 1 000 person years, in line with previously reported incidences of 0,16 per 1 000 person years. Use of combined oral contraceptives increased the risk of venous thrombosis compared with non-use (relative risk 3.5, 95% confidence interval 2.9 to 4.3). The relative risk of venous thrombosis for combined oral contraceptives with 30-35 μg ethinylestradiol and gestodene, desogestrel, cyproterone acetate, or drospirenone were similar and about 50-80% higher than for combined oral contraceptives with levonorgestrel. A dose related effect of ethinylestradiol was observed for gestodene

  4. ITER convertible blanket evaluation

    International Nuclear Information System (INIS)

    Wong, C.P.C.; Cheng, E.

    1995-01-01

    Proposed International Thermonuclear Experimental Reactor (ITER) convertible blankets were reviewed. Key design difficulties were identified. A new particle filter concept is introduced and key performance parameters estimated. Results show that this particle filter concept can satisfy all of the convertible blanket design requirements except the generic issue of Be blanket lifetime. If the convertible blanket is an acceptable approach for ITER operation, this particle filter option should be a strong candidate

  5. Power converters definitions, classification and converter topologies

    CERN Document Server

    Bordry, Frederick

    2006-01-01

    This paper introduces power conversion principles and defines the terminology. The concepts of sources and switches are defined and classified. From the basic laws of source interconnections, a generic method of power converter synthesis is presented. Some examples illustrate this systematic method. Finally, the notions of commutation cell and soft commutation are introduced and discussed.

  6. Acid-Base and Plasma Biochemical Changes Using Crystalloid Fluids in Stranded Juvenile Loggerhead Sea Turtles (Caretta caretta).

    Science.gov (United States)

    Camacho, María; Quintana, María Del Pino; Calabuig, Pascual; Luzardo, Octavio P; Boada, Luis D; Zumbado, Manuel; Orós, Jorge

    2015-01-01

    The aim of this study was to compare the efficacy and effects on acid-base and electrolyte status of several crystalloid fluids in 57 stranded juvenile loggerhead turtles. Within a rehabilitation program four different crystalloid fluids were administered (0.9% Na Cl solution; 5% dextrose + 0.9% Na Cl solutions 1:1; 0.9% Na Cl + lactated Ringer's solutions 1:1; lactated Ringer's solution). Crystalloid fluids were intracoelomically administered during three days (20 ml/kg/day). Animals were sampled at three different moments: Upon admission for evaluating the type of acid-base or biochemical disorder, post-fluid therapy treatment for controlling the evolution of the disorder, and post-recovery period for obtaining the baseline values for rehabilitated loggerhead turtles. Each sample was analyzed with a portable electronic blood analyzer for pH, pO2, pCO2, lactate, sodium, potassium, chloride, glucose, and BUN concentration. Admission and post-fluid therapy treatment values were compared with those obtained for each turtle immediately before release. The highest percentage of acid-base recovery and electrolyte balance was observed in turtles treated with mixed saline-lactated Ringer's solution (63.6%), followed by turtles treated with physiological saline solution (55%), lactated Ringer's solution (33.3%), and dextrose-saline solutions (10%). Most turtles treated with lactated Ringer's solution had lower lactate concentrations compared with their initial values; however, 66.6% of turtles treated with lactated Ringer's solution had metabolic alkalosis after therapy. Significant higher concentrations of glucose were detected after saline-dextrose administration compared with all the remaining fluids. This is the first study evaluating the effects of several crystalloid fluids on the acid-base status and plasma biochemical values in stranded loggerhead sea turtles. Reference convalescent venous blood gas, acid-base, and plasma biochemical values, useful for veterinary

  7. Venous chest anatomy: clinical implications

    International Nuclear Information System (INIS)

    Chasen, M.H.; Charnsangavej, C.

    1998-01-01

    This article provides a practical approach to the clinical implications and importance of understanding the collateral venous anatomy of the thorax. Routine radiography, conventional venography, computed tomography (CT), and magnetic resonance (MR) imaging studies provide correlative anatomic models for the demonstration of how interconnecting collateral vascular networks within the thorax maintain venous stability at all times. Five major systems comprise the collateral venous network of the thorax ( Fig. 1 ). These include the paravertebral, azygos-hemiazygos, internal mammary, lateral thoracic, and anterior jugular venous systems (AJVS). The five systems are presented in the following sequence: (a) a brief introduction to the importance of catheter position and malposition in understanding access to the thoracic venous system, (b) the anatomy of the azygos-hemiazygos systems and their relationship with the paravertebral plexus, (c) the importance of the AJVS, (d) 'loop' concepts interconnecting the internal mammary and azygos-hemiazygos systems by means of the lateral thoracic and intercostal veins, and (e) the interconnecting venous networks on the thoracic side of the thoracoabdominal junction. Certain aspects of the venous anatomy of the thorax will not be discussed in this chapter and include (a) the intra-abdominal anastomoses between the superior and inferior vena cavae (IVC) via the internal mammary, lateral thoracic, and azygos-hemiazygos systems (beyond the scope of this article), (b) potential collateral vessels involving vertebral, parascapular, thyroidal, thymic, and other smaller veins that might anastomose with the major systems, and (c) anatomic variants and pitfalls that may mimic pathologic conditions (space limitations). (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  8. Respiratory Acid-Base Disorders in the Critical Care Unit.

    Science.gov (United States)

    Hopper, Kate

    2017-03-01

    The incidence of respiratory acid-base abnormalities in the critical care unit (CCU) is unknown, although respiratory alkalosis is suspected to be common in this population. Abnormal carbon dioxide tension can have many physiologic effects, and changes in Pco 2 may have a significant impact on outcome. Monitoring Pco 2 in CCU patients is an important aspect of critical patient assessment, and identification of respiratory acid-base abnormalities can be valuable as a diagnostic tool. Treatment of respiratory acid-base disorders is largely focused on resolution of the primary disease, although mechanical ventilation may be indicated in cases with severe respiratory acidosis. Published by Elsevier Inc.

  9. [Acid-base imbalance in acute obstructive uropathies].

    Science.gov (United States)

    Belyĭ, L E

    2007-01-01

    The aim of this study was to evaluate impairment of acid-base balance (ABB) in acute obstructive uropathies. Evaluation of acid-base balance was performed by pH, partial carbon dioxide pressure, plasma bicarbonate concentration, buffer bases, basis excess, hydrogen ion concentration. An automatic gas analyzer was used, plasma anion gap was calculated. Characteristic ABB alterations in different acute obstructive uropathies were detected. Acidotic shifts in acute obstruction of the upper urinary tracts and its inflammatory complications were assessed pathophysiologically. A comparative study of pathological acid-base disorders in acute supra- and infravesical obstructive uropathies was performed.

  10. Cascaded resonant bridge converters

    Science.gov (United States)

    Stuart, Thomas A. (Inventor)

    1989-01-01

    A converter for converting a low voltage direct current power source to a higher voltage, high frequency alternating current output for use in an electrical system where it is desired to use low weight cables and other circuit elements. The converter has a first stage series resonant (Schwarz) converter which converts the direct current power source to an alternating current by means of switching elements that are operated by a variable frequency voltage regulator, a transformer to step up the voltage of the alternating current, and a rectifier bridge to convert the alternating current to a direct current first stage output. The converter further has a second stage series resonant (Schwarz) converter which is connected in series to the first stage converter to receive its direct current output and convert it to a second stage high frequency alternating current output by means of switching elements that are operated by a fixed frequency oscillator. The voltage of the second stage output is controlled at a relatively constant value by controlling the first stage output voltage, which is accomplished by controlling the frequency of the first stage variable frequency voltage controller in response to second stage voltage. Fault tolerance in the event of a load short circuit is provided by making the operation of the first stage variable frequency voltage controller responsive to first and second stage current limiting devices. The second stage output is connected to a rectifier bridge whose output is connected to the input of the second stage to provide good regulation of output voltage wave form at low system loads.

  11. Has Stewart approach improved our ability to diagnose acid-base disorders in critically ill patients?

    Science.gov (United States)

    Masevicius, Fabio D; Dubin, Arnaldo

    2015-02-04

    The Stewart approach-the application of basic physical-chemical principles of aqueous solutions to blood-is an appealing method for analyzing acid-base disorders. These principles mainly dictate that pH is determined by three independent variables, which change primarily and independently of one other. In blood plasma in vivo these variables are: (1) the PCO2; (2) the strong ion difference (SID)-the difference between the sums of all the strong (i.e., fully dissociated, chemically nonreacting) cations and all the strong anions; and (3) the nonvolatile weak acids (Atot). Accordingly, the pH and the bicarbonate levels (dependent variables) are only altered when one or more of the independent variables change. Moreover, the source of H(+) is the dissociation of water to maintain electroneutrality when the independent variables are modified. The basic principles of the Stewart approach in blood, however, have been challenged in different ways. First, the presumed independent variables are actually interdependent as occurs in situations such as: (1) the Hamburger effect (a chloride shift when CO2 is added to venous blood from the tissues); (2) the loss of Donnan equilibrium (a chloride shift from the interstitium to the intravascular compartment to balance the decrease of Atot secondary to capillary leak; and (3) the compensatory response to a primary disturbance in either independent variable. Second, the concept of water dissociation in response to changes in SID is controversial and lacks experimental evidence. In addition, the Stewart approach is not better than the conventional method for understanding acid-base disorders such as hyperchloremic metabolic acidosis secondary to a chloride-rich-fluid load. Finally, several attempts were performed to demonstrate the clinical superiority of the Stewart approach. These studies, however, have severe methodological drawbacks. In contrast, the largest study on this issue indicated the interchangeability of the Stewart and

  12. The Incidence of Electrolytes and Acid-Base Abnormalities in ...

    African Journals Online (AJOL)

    Diabetic patients with prolonged insulin insufficiency can present in the emergency department with life threatening ketoacidosis,el ectrolyte ... acid-base abnormalities in diabetic emergencies using the I-STAT point of care testing technique.

  13. An Olfactory Indicator for Acid-Base Titrations.

    Science.gov (United States)

    Flair, Mark N.; Setzer, William N.

    1990-01-01

    The use of an olfactory acid-base indicator in titrations for visually impaired students is discussed. Potential olfactory indicators include eugenol, thymol, vanillin, and thiophenol. Titrations performed with each indicator with eugenol proved to be successful. (KR)

  14. Acid-base homeostasis in the human system

    Science.gov (United States)

    White, R. J.

    1974-01-01

    Acid-base regulation is a cooperative phenomena in vivo with body fluids, extracellular and intracellular buffers, lungs, and kidneys all playing important roles. The present account is much too brief to be considered a review of present knowledge of these regulatory systems, and should be viewed, instead, as a guide to the elements necessary to construct a simple model of the mutual interactions of the acid-base regulatory systems of the body.

  15. Effects of chronic acetazolamide administration on gas exchange and acid-base control in pulmonary circulation in exercising horses.

    Science.gov (United States)

    Vengust, M; Stämpfli, H; De Moraes, A N; Teixeiro-Neto, F; Viel, L; Heigenhauser, G

    2010-11-01

    Carbonic anhydrase (CA) catalyses the hydration/dehydration reaction of CO(2) and increases the rate of Cl(-) and HCO(3)(-) exchange between the erythrocytes and plasma. Therefore, chronic inhibition of CA has a potential to attenuate CO(2) output and induce greater metabolic and respiratory acidosis in exercising horses. To determine the effects of Carbonic anhydrase inhibition on CO(2) output and ionic exchange between erythrocytes and plasma and their influence on acid-base balance in the pulmonary circulation (across the lung) in exercising horses with and without CA inhibition. Six horses were exercised to exhaustion on a treadmill without (Con) and with CA inhibition (AczTr). CA inhibition was achieved with administration of acetazolamide (10 mg/kg bwt t.i.d. for 3 days and 30 mg/kg bwt before exercise). Arterial, mixed venous blood and CO(2) output were sampled at rest and during exercise. An integrated physicochemical systems approach was used to describe acid base changes. AczTr decreased the duration of exercise by 45% (P changes across the lung with exception of lactate. CO(2) and chloride changes in erythrocytes across the lung seem to be the major contributors to acid-base and ions balance in pulmonary circulation in exercising horses. © 2010 EVJ Ltd.

  16. Surgical management of venous malformations.

    Science.gov (United States)

    Loose, D A

    2007-01-01

    Among vascular malformations, the predominantly venous malformations represent the majority of cases. They form a clinical entity and therefore need clear concepts concerning diagnosis and treatment. This paper presents an overview of contemporary classification as well as tactics and techniques of treatment. According to the Hamburg Classification, predominantly venous malformations are categorized into truncular and extratruncular forms, with truncular forms distinguished as obstructions and dilations, and extratruncular forms as limited or infiltrating. The tactics of treatment represent surgical and non-surgical methods or combined techniques. Surgical approaches utilize different tactics and techniques that are adopted based on the pathologic form and type of the malformation: (I) operation to reduce the haemodynamic activity of the malformation; (II) operation to eliminate the malformation; and (III) reconstructive operation. As for (I), a type of a tactic is the operation to derive the venous flow. In (II), the total or partial removal of the venous malformation is demonstrated subdivided into three different techniques. In this way, the infiltrating as well as the limited forms can be treated. An additional technique is dedicated to the treatment of a marginal vein. Approach (III) involves the treatment of venous aneurysms, where a variety of techniques have been successful. Long-term follow-up demonstrates positive results in 91% of the cases. Congenital predominantly venous malformations should be treated according to the principles developed during the past decades in vascular surgery, interventional treatment and multidisciplinary treatment. The days of predominantly conservative treatment should be relegated to the past. Special skills and experiences are necessary to carry out appropriate surgical strategy, and the required operative techniques should be dictated by the location and type of malformation and associated findings.

  17. SSG Wave Energy Converter

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Vicinanza, Diego; Frigaard, Peter

    2008-01-01

    The SSG (Sea Slot-cone Generator) is a wave energy converter of the overtopping type. The structure consists of a number of reservoirs one on the top of each others above the mean water level, in which the water of incoming waves is stored temporary. In each reservoir, expressively designed low...... head hydroturbines are converting the potential energy of the stored water into power. A key to success for the SSG will be the low cost of the structure and its robustness. The construction of the pilot plant is scheduled and this paper aims to describe the concept of the SSG wave energy converter...

  18. Venous abnormalities demonstrated by computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, T; Tsukune, Y; Ashida, H; Tokuda, M; Oyama, Y [St. Marianna Univ., Kawasaki, Kanagawa (Japan). School of Medicine

    1980-05-01

    CT is capable of demonstrating various venous changes. However, little have been described on this subject in the literature. Examples of various venous abnormalities such as obstructed jugular vein, superior and inferior vena cava (IVC), tumor invasion of IVC and renal vein and venous changes in portal hypertension were presented. It was stressed that noninvasive CT is a good tool in diagnosis of some of venous changes and may be able to eliminate angiography in such cases.

  19. Colorectal cancer with venous tumor thrombosis

    OpenAIRE

    Kensuke Otani; Soichiro Ishihara; Keisuke Hata; Koji Murono; Kazuhito Sasaki; Koji Yasuda; Takeshi Nishikawa; Toshiaki Tanaka; Tomomichi Kiyomatsu; Kazushige Kawai; Hiroaki Nozawa; Hironori Yamaguchi; Toshiaki Watanabe

    2018-01-01

    Summary: Colorectal cancer is seldom accompanied by venous tumor thrombosis, and little is known about the features of venous tumor thrombosis in colorectal cancer. However, some reports show that colorectal cancer patients can develop venous tumor thrombosis and warn clinicians not to overlook this complication. In this report, we perform a review of 43 previously reported cases and investigate the characteristics of colorectal cancer accompanied by venous tumor thrombosis. The histological ...

  20. Pattern of acid base abnormalities in critically ill patinets

    International Nuclear Information System (INIS)

    Ahmad, T.M.; Mehmood, A.; Malik, T.M.

    2015-01-01

    To find out the pattern of acid base abnormalities in critically ill patients in a tertiary care health facility. Study Design: A descriptive study. Place and Duration of Study: The study was carried out in the department of pathology, Combined Military Hospital Kharian from January 2013 to June 2013. Patients and Methods: Two hundred and fifty patients suffering from various diseases and presenting with exacerbation of their clinical conditions were studied. These patients were hospitalized and managed in acute care units of the hospital. Arterial blood gases were analysed to detect acid base status and their correlation with their clinical condition. Concomitant analysis of electrolytes was carried out. Tests related to concurrent illnesses e.g. renal and liver function tests, cardiac enzymes and plasma glucose were assayed by routine end point and kinetic methods. Standard reference materials were used to ensure internal quantify control of analyses. Results: Two hundred and fifteen patients out of 250 studied suffered from acid base disorders. Gender distribution showed a higher percentage of male patients and the mean age was 70.5 ± 17.4 years. Double acid base disorders were the commonest disorders (34%) followed by metabolic acidosis (30%). Anion gap was calculated to further stratify metabolic acidosis and cases of diabetic ketoacidosis were the commonest in this category (47%). Other simple acid base disorders were relatively less frequent. Delta bicarbonate was calculated to unmask the superimposition of respiratory alkalosis or acidosis with metabolic acidosis and metabolic alkalosis. Though triple acid base disorders were noted in a small percentage of cases (05%), but were found to be the most complicated and challenging. Mixed acid base disorders were associated with high mortality. Conclusion: A large number of critically ill patients manifested acid base abnormalities over the full spectrum of these disorders. Mixed acid base disorders were

  1. Electric current - frequency converter

    International Nuclear Information System (INIS)

    Kumahara, Tadashi; Kinbana, Setsuro.

    1967-01-01

    Herein disclosed is an improved simple electric current-frequency converter, the input current and output frequency linearity of which is widened to a range of four to five figures while compensating, for temperature. The converter may be used for computor processing and for telemetering the output signals from a nuclear reactor. The converter is an astable multivibrator which includes charging circuits comprising emitter-voltage compensated NPN transistors, a charged voltage detecting circuit of temperature compensated field effect transistors, and a transistor switching circuit for generating switching pulses independent of temperature. The converter exhibited a 0.7% frequency change within a range of 5 - 45 0 C and less than a 0.1% frequency drift after six hours of operation when the input current was maintained constant. (Yamaguchi, T.)

  2. Improving Power Converter Reliability

    DEFF Research Database (Denmark)

    Ghimire, Pramod; de Vega, Angel Ruiz; Beczkowski, Szymon

    2014-01-01

    of a high-power IGBT module during converter operation, which may play a vital role in improving the reliability of the power converters. The measured voltage is used to estimate the module average junction temperature of the high and low-voltage side of a half-bridge IGBT separately in every fundamental......The real-time junction temperature monitoring of a high-power insulated-gate bipolar transistor (IGBT) module is important to increase the overall reliability of power converters for industrial applications. This article proposes a new method to measure the on-state collector?emitter voltage...... is measured in a wind power converter at a low fundamental frequency. To illustrate more, the test method as well as the performance of the measurement circuit are also presented. This measurement is also useful to indicate failure mechanisms such as bond wire lift-off and solder layer degradation...

  3. Thermionic photovoltaic energy converter

    Science.gov (United States)

    Chubb, D. L. (Inventor)

    1985-01-01

    A thermionic photovoltaic energy conversion device comprises a thermionic diode mounted within a hollow tubular photovoltaic converter. The thermionic diode maintains a cesium discharge for producing excited atoms that emit line radiation in the wavelength region of 850 nm to 890 nm. The photovoltaic converter is a silicon or gallium arsenide photovoltaic cell having bandgap energies in this same wavelength region for optimum cell efficiency.

  4. Familial Clustering of Venous Thromboembolism

    DEFF Research Database (Denmark)

    Sindet-Pedersen, Caroline; Oestergaard, Louise Bruun; Gundlund, Anna

    2016-01-01

    BACKGROUND: Identification of risk factors for venous thromboembolism (VTE) is of utmost importance to improve current prophylactic regimes and treatment guidelines. The extent to which a family history contributes to the risk of VTE needs further exploration. OBJECTIVES: To examine the relative ...

  5. Venous thrombosis : a patient's view

    NARCIS (Netherlands)

    Korlaar, Inez van

    2006-01-01

    The studies described in this thesis had two main aims: 1) To study the quality of life of patients with venous thrombosis and to examine the role of illness perceptions in explaining the quality of life of these patients. 2) To assess the psychological consequences of genetic testing for

  6. History of venous leg ulcers.

    Science.gov (United States)

    Gianfaldoni, S; Wollina, U; Lotti, J; Gianfaldoni, R; Lotti, T; Fioranelli, M; Roccia, M G

    To retrieve the history of venous ulcers and of skin lesions in general, we must go back to the appearance of human beings on earth. It is interesting to note that cutaneous injuries evolved parallel to human society. An essential first step in the pathogenesis of ulcers was represented by the transition of the quadruped man to Homo Erectus. This condition was characterized by a greater gravitational pressure on the lower limbs, with consequences on the peripheral venous system. Furthermore, human evolution was characterized by an increased risk of traumatic injuries, secondary to his natural need to create fire and hunt (e.g. stones, iron, fire, animal fighting). Humans then began to fight one another until they came to real wars, with increased frequency of wounds and infectious complications. The situation degraded with the introduction of horse riding, introduced by the Scites, who first tamed animals in the 7th century BC. This condition exhibited iliac veins at compression phenomena, favouring the venous stasis. With time, man continued to evolve until the modern age, which is characterized by increased risk factors for venous wounds such as poor physical activity and dietary errors (1, 2).

  7. Splanchnic venous thrombosis and pancreatitis.

    Science.gov (United States)

    Nadkarni, Nikhil A; Khanna, Sahil; Vege, Santhi Swaroop

    2013-08-01

    Pancreatitis is an inflammatory process with local and systemic manifestations. One such local manifestation is thrombosis in splanchnic venous circulation, predominantly of the splenic vein. The literature on this important complication is very sparse. This review offers an overview of mechanism of thrombosis, its pathophysiology, diagnosis, and management in the setting of acute as well as chronic pancreatitis.

  8. Neonatal Acid-Base Status in Fetuses with Abnormal Vertebro- and Cerebro-Placental Ratios.

    Science.gov (United States)

    Morales-Roselló, José; Khalil, Asma; Ferri-Folch, Blanca; Perales-Marín, Alfredo

    2015-01-01

    A low cerebro-placental ratio (CPR) at term suggests the existence of failure to reach growth potential (FRGP) with a higher risk of poor neonatal acid-base status. This study aimed to evaluate whether similar findings were also seen in the vertebral artery (vertebro-placental ratio, VPR), supplying 30% of the cerebral flow. We studied term fetuses classified into groups according to birth weight (BW), CPR and VPR. BW was expressed in centiles and ratios in multiples of the median (MoM). Subsequently, associations with neonatal pH values were evaluated by means of regression curves and Mann-Whitney tests. VPR MoM correlated with BW centiles (p < 0.0001, R2 = 0.042) and its distribution resembled that of CPR MoM (p < 0.001). When both arteries were compared, adequate-for-gestational-age (AGA) fetuses with either low CPR or low VPR had lower neonatal venous pH values (p < 0.05, p < 0.01, respectively). However, in case of small-for-gestational-age (SGA) fetuses, only those with low VPR had significantly lower neonatal arterial and venous pH values (p < 0.05). Blood flow in the vertebral artery mimics that in the middle cerebral artery supporting the FRGP model. Both CPR and VPR identify AGA fetuses with lower neonatal pH values, but only VPR identifies SGA with lower pH values. Hypoxemia might be reflected as a generalized cerebral vasodilation demonstrated as low CPR and VPR.

  9. Renal acidification responses to respiratory acid-base disorders.

    Science.gov (United States)

    Madias, Nicolaos E

    2010-01-01

    Respiratory acid-base disorders are those abnormalities in acid-base equilibrium that are expressed as primary changes in the arterial carbon dioxide tension (PaCO2). An increase in PaCO2 (hypercapnia) acidifies body fluids and initiates the acid-base disturbance known as respiratory acidosis. By contrast, a decrease in PaCO2 (hypocapnia) alkalinizes body fluids and initiates the acid-base disturbance known as respiratory alkalosis. The impact on systemic acidity of these primary changes in PaCO2 is ameliorated by secondary, directional changes in plasma [HCO3¯] that occur in 2 stages. Acutely, hypercapnia or hypocapnia yields relatively small changes in plasma [HCO3¯] that originate virtually exclusively from titration of the body's nonbicarbonate buffers. During sustained hypercapnia or hypocapnia, much larger changes in plasma [HCO3¯] occur that reflect adjustments in renal acidification mechanisms. Consequently, the deviation of systemic acidity from normal is smaller in the chronic forms of these disorders. Here we provide an overview of the renal acidification responses to respiratory acid-base disorders. We also identify gaps in knowledge that require further research.

  10. Assessment of acid-base balance. Stewart's approach.

    Science.gov (United States)

    Fores-Novales, B; Diez-Fores, P; Aguilera-Celorrio, L J

    2016-04-01

    The study of acid-base equilibrium, its regulation and its interpretation have been a source of debate since the beginning of 20th century. Most accepted and commonly used analyses are based on pH, a notion first introduced by Sorensen in 1909, and on the Henderson-Hasselbalch equation (1916). Since then new concepts have been development in order to complete and make easier the understanding of acid-base disorders. In the early 1980's Peter Stewart brought the traditional interpretation of acid-base disturbances into question and proposed a new method. This innovative approach seems more suitable for studying acid-base abnormalities in critically ill patients. The aim of this paper is to update acid-base concepts, methods, limitations and applications. Copyright © 2015 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  11. Tailoring peritoneal dialysis fluid for optimal acid-base targets.

    Science.gov (United States)

    Feriani, Mariano

    2009-01-01

    Mild derangements of acid-base status are common features in peritoneal dialysis patients, metabolic acidosis being the most frequent alteration. One of the main tasks of dialysis is to correct these derangements and the target is the normalization of the acid-base parameters since they affect several organs and functions. Since factors affecting acid-base homeostasis are intrinsic characteristics of the individual patient (metabolic acid production, distribution space for bicarbonate, dialytic prescription, etc.), it is not surprising that only relatively few patients achieve the normal range. Only a certain modulation of buffer infusion by using different buffer concentrations in the dialysis fluid may ensure a good correction in a large percentage of patients.

  12. Assessing Acid-Base Status: Physiologic Versus Physicochemical Approach.

    Science.gov (United States)

    Adrogué, Horacio J; Madias, Nicolaos E

    2016-11-01

    The physiologic approach has long been used in assessing acid-base status. This approach considers acids as hydrogen ion donors and bases as hydrogen ion acceptors and the acid-base status of the organism as reflecting the interaction of net hydrogen ion balance with body buffers. In the physiologic approach, the carbonic acid/bicarbonate buffer pair is used for assessing acid-base status and blood pH is determined by carbonic acid (ie, Paco 2 ) and serum bicarbonate levels. More recently, the physicochemical approach was introduced, which has gained popularity, particularly among intensivists and anesthesiologists. This approach posits that the acid-base status of body fluids is determined by changes in the dissociation of water that are driven by the interplay of 3 independent variables: the sum of strong (fully dissociated) cation concentrations minus the sum of strong anion concentrations (strong ion difference); the total concentration of weak acids; and Paco 2 . These 3 independent variables mechanistically determine both hydrogen ion concentration and bicarbonate concentration of body fluids, which are considered as dependent variables. Our experience indicates that the average practitioner is familiar with only one of these approaches and knows very little, if any, about the other approach. In the present Acid-Base and Electrolyte Teaching Case, we attempt to bridge this knowledge gap by contrasting the physiologic and physicochemical approaches to assessing acid-base status. We first outline the essential features, advantages, and limitations of each of the 2 approaches and then apply each approach to the same patient presentation. We conclude with our view about the optimal approach. Copyright © 2016 National Kidney Foundation, Inc. All rights reserved.

  13. Venous sinus stenting for pseudotumour cerebri with venous sinus stenosis

    International Nuclear Information System (INIS)

    Chen Huairui; Bai Rulin; Wu Xiaojun; Qi Xiangqian; Mei Qiyong; Lu Yicheng

    2011-01-01

    Objective: To explore the relation between venous sinus stenosis and pseduotumour cerebri and to discuss the efficacy and strategy of venous sinus stenting for its treatment. Methods: Venous sinus stenting was performed in a total of 9 patients with pseudotumour cerebri accompanied by dural sinus stenosis. The clinical data, including the clinical presentations, intracranial pressure, angiographic findings, pressure of dural sinus,methods of treatment and the therapeutic results, were retrospectively analyzed. Results: Bilateral disc edema was seen in all patients. The pressure gradient in the lateral sinuses was obviously high before stenting (22.67±7.25)mmHg in all patients and a reduction in intra-sinus pressure and pressure gradient was also found (5.78±3.77)mmHg. The symptoms associated with intracranial hypertension were gradually improved or disappeared in two weeks after the placement of the stent in all cases, and the intracranial pressure dropped evidently (12.78±5.97)cm H 2 O. Vision was improved in 7 cases at three months, whereas it remained poor in 2 cases despite normalized intracranial pressure. There was no other permanent procedure-related morbidity. The patients were followed up for 3 months to 5 years, and no recurrence developed. Conclusion: Lateral sinus stenting is an effective method for the treatment of pseudotumour cerebri with dural sinus stenosis. (authors)

  14. Radiologically-placed venous ports in children under venous anesthesia

    International Nuclear Information System (INIS)

    Jang, Joo Yeon; Jeon, Ung Bae; Choo, Ki Seok; Hwang, Jae Yeon; Kim, Yong Woo; Lee, Yun Jin; Nam, Sang Ool; Lim, Young Tak

    2015-01-01

    To evaluate the efficacy and safety of radiologic venous port placement in children under venous anesthesia. Between April 2009 and July 2011, 44 ports were implanted in 41 children (24 boys, 17 girls). The age of patients ranged from 9 months to 19 years (mean, 6.5 years) and their body weights ranged from 6.8 kg to 56.3 kg (mean, 23.2 kg). Right internal jugular vein access was used in 42 ports, right subclavian vein in 1, and left subclavian in 1. Durability and complications of port implantation were reviewed. The technical success rate was 100%. The catheter life was 10-661 days (mean 246 days). Two patients died during the follow-up period, 21 and 6 ports were removed at the end of treatment or as a result of complications, respectively. One port was removed and replaced by a Hickmann catheter. Three ports were explanted due to port-related sepsis, one due to a catheter kink, and two for unexplained fever or insertion site pain. The overall port-related infection was 3 cases (6.8%, 0.28/1000 catheter days). Venous port placement by interventional radiologists in children under intravenous sedation is relatively safe, with a high rate of technical success and low rate of complications.

  15. Radiologically-placed venous ports in children under venous anesthesia

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Joo Yeon; Jeon, Ung Bae; Choo, Ki Seok; Hwang, Jae Yeon; Kim, Yong Woo; Lee, Yun Jin; Nam, Sang Ool; Lim, Young Tak [Pusan National University School of Medicine, Yangsan (Korea, Republic of)

    2015-02-15

    To evaluate the efficacy and safety of radiologic venous port placement in children under venous anesthesia. Between April 2009 and July 2011, 44 ports were implanted in 41 children (24 boys, 17 girls). The age of patients ranged from 9 months to 19 years (mean, 6.5 years) and their body weights ranged from 6.8 kg to 56.3 kg (mean, 23.2 kg). Right internal jugular vein access was used in 42 ports, right subclavian vein in 1, and left subclavian in 1. Durability and complications of port implantation were reviewed. The technical success rate was 100%. The catheter life was 10-661 days (mean 246 days). Two patients died during the follow-up period, 21 and 6 ports were removed at the end of treatment or as a result of complications, respectively. One port was removed and replaced by a Hickmann catheter. Three ports were explanted due to port-related sepsis, one due to a catheter kink, and two for unexplained fever or insertion site pain. The overall port-related infection was 3 cases (6.8%, 0.28/1000 catheter days). Venous port placement by interventional radiologists in children under intravenous sedation is relatively safe, with a high rate of technical success and low rate of complications.

  16. Acid-Base Behavior of Carboxylic Acid Groups Covalently Attached at the Surface of Polyethylene: The Usefulness of Contact Angle in Following the Ionization of Surface Functionality

    Science.gov (United States)

    1985-08-01

    additional check, we converted granular PE-CO 2H to granular PE-CO 2CH3 by acid -catalyzed esterification. This material had no titrable groups. Upon...Task No. NR-631-840 TECHNICAL REPORT NO. 85-1 Acid -Base Behavior of Carboxylic Acid Groups Covalently Attached at the Surface of Polyethylene: The...34I Acid -Base Behavior K-142 ofCarboxylicAcidGroupsAttached...______________________ 12. PERSIIMAL AUTHOR IS) S.R. Holmes-Farly., R.H. Reamey, T.J

  17. Acids and bases solvent effects on acid-base strenght

    CERN Document Server

    Cox, Brian G

    2013-01-01

    Acids and bases are ubiquitous in chemistry. Our understanding of them, however, is dominated by their behaviour in water. Transfer to non-aqueous solvents leads to profound changes in acid-base strengths and to the rates and equilibria of many processes: for example, synthetic reactions involving acids, bases and nucleophiles; isolation of pharmaceutical actives through salt formation; formation of zwitter- ions in amino acids; and chromatographic separation of substrates. This book seeks to enhance our understanding of acids and bases by reviewing and analysing their behaviour in non-aqueous solvents. The behaviour is related where possible to that in water, but correlations and contrasts between solvents are also presented.

  18. Acid-base equilibrium: The best clinical approach

    OpenAIRE

    Aristizábal-Salazar, Raúl E; Calvo-Torres, L. Felipe; Valencia-Arango, Luis Alfonso; Montoya-Canon, Mauricio; Barbosa-Gantiva, Oscar; Hincapié-Baena, Vanessa

    2015-01-01

    Acid-base balance disorders can be found in a primary or secondary form in patients with a disease process such as Diabetes Mellitus or acute renal failure, among others. The objective of this article is to explain and guide the correlation ship between the clinical findings in the patient and the parameters of arterial blood gases in a simple and precise manner, in order to make the correct acid-base balance diagnosis and adequate therapeutic interventions. A non-systematic review of the sci...

  19. Teaching acid/base physiology in the laboratory

    DEFF Research Database (Denmark)

    Friis, Ulla G; Plovsing, Ronni; Hansen, Klaus

    2010-01-01

    exercise in acid/base physiology that would provide students with unambiguous and reproducible data that clearly would illustrate the theory in practice. The laboratory exercise was developed to include both metabolic acidosis and respiratory alkalosis. Data were collected from 56 groups of medical...... students that had participated in this laboratory exercise. The acquired data showed very consistent and solid findings after the development of both metabolic acidosis and respiratory alkalosis. All results were consistent with the appropriate diagnosis of the acid/base disorder. Not one single group...... failed to obtain data that were compatible with the diagnosis; it was only the degree of acidosis/alkalosis and compensation that varied....

  20. Mixed Capillary Venous Retroperitoneal Hemangioma

    Directory of Open Access Journals (Sweden)

    Mohit Godar

    2013-01-01

    Full Text Available We report a case of mixed capillary venous hemangioma of the retroperitoneum in a 61-year-old man. Abdominal ultrasonography showed a mass to be hypoechoic with increased flow in color Doppler imaging. Dynamic contrast-enhanced computed tomography revealed a centripetal filling-in of the mass, located anterior to the left psoas muscle at the level of sacroiliac joint. On the basis of imaging features, preoperative diagnosis of hemangioma was considered and the mass was excised by laparoscopic method. Immunohistochemical studies were strongly positive for CD31 and CD34, and negative for calretinin, EMA, WT1, HMB45, Ki67, synaptophysin, and lymphatic endothelial cell marker D2–40. Histologically, the neoplasm was diagnosed as mixed capillary venous hemangioma.

  1. MRI in venous thromboembolic disease

    International Nuclear Information System (INIS)

    Sostman, H.D.; Debatin, J.F.; Spritzer, C.E.; Coleman, R.E.; Grist, T.M.; MacFall, J.R.

    1993-01-01

    We evaluated the ability of magnetic resonance (MR) imaging to detect deep venous thrombosis (DVT) and pulmonary embolism (PE). MR venography was performed on 217 patients suspected of having DVT. Cine-MR imaging of the pulmonary arteries was performed in 14 other patients who were thought to have PE based on other imaging studies. In a third group of 5 patients, MR pulmonary angiograms were performed in the sagittal and coronal planes with a multislice fast gradient recalled echo technique. All but one of the 217 MR venograms were technically adequate. In 72 patients with correlative imaging studies (venography and ultrasound) MR venography was 99% sensitive and 95% specific. On the basis of follow-up (mean 8.3 months), no false-negative MR venograms were detected in an additional 64 patients. In 11 other patients MR revealed a diagnosis other than DVT. Cine-MR showed PE in all 14 patients evaluated. MR pulmonary arteriography demonstrated filling defects consistent with acute PE in 2 of 3 patients with acute PE; in the third patient only a questionable filling defect was seen. Coarctations or webs were found in the pulmonary arteries of both patients with chronic PE. These preliminary data suggest that MR imaging may be able to evaluate both the peripheral venous and the pulmonary arterial component of venous thromboembolic disease. Further technical refinement and more extensive clinical experience will be required to establish the role of this method in diagnosing pulmonary embolism, but MR venography is now used routinely in our hospital for the diagnosis of deep venous thrombosis. (orig.)

  2. Significance of venous anastomosis in fingertip replantation.

    Science.gov (United States)

    Hattori, Yasunori; Doi, Kazuteru; Ikeda, Keisuke; Abe, Yukio; Dhawan, Vikas

    2003-03-01

    Adequate venous outflow is the most important factor for successful fingertip replantation. The authors have attempted venous anastomosis in all cases of fingertip replantation to overcome postoperative congestion. In this article, the significance of venous repair for fingertip replantation is described from the authors' results of 64 complete fingertip amputations in 55 consecutive patients, which were replanted from January of 1996 to June of 2001. The overall survival rate was 86 percent. Of the 44 replantations in zone I, 37 survived, and the success rate was 84 percent. Of the 20 replantations in zone II, 18 survived, and the success rate was 90 percent. Venous anastomosis was attempted in all cases, but it was possible in 39 zone I and in all zone II replantations. For arterial repair, vein grafts were necessary in 17 of the 44 zone I and in one of the 20 zone II replantations; for venous repair, they were necessary in six zone I replantations and one zone II replantation. Postoperative vascular complications occurred in 15 replantations. There were five cases of arterial thrombosis and 10 cases of venous congestion. Venous congestion occurred in nine zone I and one zone II replantations. In five of these 10 replantations, venous anastomosis was not possible. In another five replantations, venous outflow was established at the time of surgery, but occlusion occurred subsequently. Except for the five failures resulting from arterial thrombosis, successful venous repair was possible in 49 of 59 replantations (83 percent). Despite the demand for skillful microsurgical technique and longer operation time, the authors' results using venous anastomosis in successful fingertip replantations are encouraging. By performing venous anastomosis, external bleeding can be avoided and a higher survival rate can be achieved. Venous anastomosis for fingertip replantation is a reliable and worthwhile procedure.

  3. Cerebral sino-venous thrombosis

    International Nuclear Information System (INIS)

    Sayama, Ichiro; Kobayashi, Tsunesaburo; Nakajima, Kenji

    1982-01-01

    Three cases of cerebral sino-venous thrombosis were reported. Repeated CT findings were studied and discussed on account of the treatments for those pathologic conditions. Those of studied cases are; a 22-year-old postpartum woman, a 42-year-old woman with irregular vaginal bleeding, and a 26-year-old man with severe reactive emesis after drinking alcohol. They were treated conservatively. Case 1 died in its acute stage. In the remaining ones, each had an uneventful recovery. CT scan findings of them manifested their exact clinical conditions. These findings were devided into two categories, one was direct signs expressed sino-venous occlusion, the other was indirect signs which appeared as a result of these occlusion. Direct signs cannot always get in every cases with sino-venous occlusion, but as for indirect signs, we can get various changes corresponding to the time taken CT photoes, and they are useful to decide appropriate treatments at that time. Considering suitable treatments for this disease, it is necessary to select most suitable ones according to their pathologic conditions, which may be precisely drawn with CT scans. (J.P.N.)

  4. An Electromagnetic Beam Converter

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to an electromagnetic beam converter and a method for conversion of an input beam of electromagnetic radiation having a bell shaped intensity profile a(x,y) into an output beam having a prescribed target intensity profile l(x',y') based on a further development...

  5. Converting the reset

    NARCIS (Netherlands)

    J.K. Hoogland (Jiri); C.D.D. Neumann; D. Bloch

    2001-01-01

    textabstractWe give a simple algorithm to incorporate the effects of resets in convertible bond prices, without having to add an extra factor to take into account the value of the reset. Furthermore we show that the effect of a notice period, and additional make-whole features, can be treated in a

  6. Definition of Power Converters

    CERN Document Server

    Bordry, F

    2015-01-01

    The paper is intended to introduce power conversion principles and to define common terms in the domain. The concept s of sources and switches are defined and classified. From the basic laws of source interconnections, a generic method of power converter synthesis is presented. Some examples illustrate this systematic method. Finally, the commutation cell and soft commuta tion are introduced and discussedd.

  7. Thermoelectrode for thermoelectric converter

    International Nuclear Information System (INIS)

    Bodiul, Pavel; Bondarciuc, Nicolae; Ghitu, Dumitru; Nikolaeva, Albina; Konopko, Leonid; Turcan, Ana

    2008-01-01

    The invention relates to the electronic engneering and can be used for manufacturing of thermoelectrodes for thermoelectric converters. The thermoelectrode is made of semiconductor anisotropic material in the form of thread in glass insulation. At the same timer, the thread is made of stannum-doped tellurium in the ratio of 0.1...3 at.%.

  8. Students' Understanding of Acids/Bases in Organic Chemistry Contexts

    Science.gov (United States)

    Cartrette, David P.; Mayo, Provi M.

    2011-01-01

    Understanding key foundational principles is vital to learning chemistry across different contexts. One such foundational principle is the acid/base behavior of molecules. In the general chemistry sequence, the Bronsted-Lowry theory is stressed, because it lends itself well to studying equilibrium and kinetics. However, the Lewis theory of…

  9. A dipstick sensor for coulometric acid-base titrations

    NARCIS (Netherlands)

    Olthuis, Wouter; van der Schoot, B.H.; Chavez, F.; Bergveld, Piet

    1989-01-01

    By performing an acid-base titration by coulometric generation of OH− or H+ ions at an inert electrode in close proximity to the pH-sensitive gate of an ISFET, it is possible to determine the acid or base concentration of a solution using the ISFET as an indicator device for the equivalence point in

  10. Using Spreadsheets to Produce Acid-Base Titration Curves.

    Science.gov (United States)

    Cawley, Martin James; Parkinson, John

    1995-01-01

    Describes two spreadsheets for producing acid-base titration curves, one uses relatively simple cell formulae that can be written into the spreadsheet by inexperienced students and the second uses more complex formulae that are best written by the teacher. (JRH)

  11. Dynamic Buffer Capacity in Acid-Base Systems.

    Science.gov (United States)

    Michałowska-Kaczmarczyk, Anna M; Michałowski, Tadeusz

    The generalized concept of 'dynamic' buffer capacity β V is related to electrolytic systems of different complexity where acid-base equilibria are involved. The resulting formulas are presented in a uniform and consistent form. The detailed calculations are related to two Britton-Robinson buffers, taken as examples.

  12. Boronic acid-based autoligation of nucleic acids

    DEFF Research Database (Denmark)

    Barbeyron, R.; Vasseur, J.-J.; Smietana, M.

    2013-01-01

    Abstract: The development of synthetic systems displaying dynamic and adaptive characteristics is a formidable challenge with wide applications from biotechnology to therapeutics. Recently, we described a dynamic and programmable nucleic acid-based system relying on the formation of reversible bo....... Evidence suggests that geometric and steric factors are key features for controlling the equilibria. Graphical Abstract: [Figure not available: see fulltext.]...

  13. Acid-Base Disorders--A Computer Simulation.

    Science.gov (United States)

    Maude, David L.

    1985-01-01

    Describes and lists a program for Apple Pascal Version 1.1 which investigates the behavior of the bicarbonate-carbon dioxide buffer system in acid-base disorders. Designed specifically for the preclinical medical student, the program has proven easy to use and enables students to use blood gas parameters to arrive at diagnoses. (DH)

  14. Dynamic Buffer Capacity in Acid?Base Systems

    OpenAIRE

    Micha?owska-Kaczmarczyk, Anna M.; Micha?owski, Tadeusz

    2015-01-01

    The generalized concept of ?dynamic? buffer capacity ? V is related to electrolytic systems of different complexity where acid?base equilibria are involved. The resulting formulas are presented in a uniform and consistent form. The detailed calculations are related to two Britton?Robinson buffers, taken as examples.

  15. The Convertible Arbitrage Strategy Analyzed

    NARCIS (Netherlands)

    Loncarski, I.; Ter Horst, J.R.; Veld, C.H.

    2006-01-01

    This paper analyzes convertible bond arbitrage on the Canadian market for the period 1998 to 2004.Convertible bond arbitrage is the combination of a long position in convertible bonds and a short position in the underlying stocks. Convertible arbitrage has been one of the most successful strategies

  16. The role of acid-base imbalance in statin-induced myotoxicity.

    Science.gov (United States)

    Taha, Dhiaa A; De Moor, Cornelia H; Barrett, David A; Lee, Jong Bong; Gandhi, Raj D; Hoo, Chee Wei; Gershkovich, Pavel

    2016-08-01

    Disturbances in acid-base balance, such as acidosis and alkalosis, have potential to alter the pharmacologic and toxicologic outcomes of statin therapy. Statins are commonly prescribed for elderly patients who have multiple comorbidities such as diabetes mellitus, cardiovascular, and renal diseases. These patients are at risk of developing acid-base imbalance. In the present study, the effect of disturbances in acid-base balance on the interconversion of simvastatin and pravastatin between lactone and hydroxy acid forms have been investigated in physiological buffers, human plasma, and cell culture medium over pH ranging from 6.8-7.8. The effects of such interconversion on cellular uptake and myotoxicity of statins were assessed in vitro using C2C12 skeletal muscle cells under conditions relevant to acidosis, alkalosis, and physiological pH. Results indicate that the conversion of the lactone forms of simvastatin and pravastatin to the corresponding hydroxy acid is strongly pH dependent. At physiological and alkaline pH, substantial proportions of simvastatin lactone (SVL; ∼87% and 99%, respectively) and pravastatin lactone (PVL; ∼98% and 99%, respectively) were converted to the active hydroxy acid forms after 24 hours of incubation at 37°C. At acidic pH, conversion occurs to a lower extent, resulting in greater proportion of statin remaining in the more lipophilic lactone form. However, pH alteration did not influence the conversion of the hydroxy acid forms of simvastatin and pravastatin to the corresponding lactones. Furthermore, acidosis has been shown to hinder the metabolism of the lactone form of statins by inhibiting hepatic microsomal enzyme activities. Lipophilic SVL was found to be more cytotoxic to undifferentiated and differentiated skeletal muscle cells compared with more hydrophilic simvastatin hydroxy acid, PVL, and pravastatin hydroxy acid. Enhanced cytotoxicity of statins was observed under acidic conditions and is attributed to increased

  17. Yarrowia lipolytica as an Oleaginous Cell Factory Platform for Production of Fatty Acid-Based Biofuel and Bioproducts

    Energy Technology Data Exchange (ETDEWEB)

    Abghari, Ali; Chen, Shulin, E-mail: chens@wsu.edu [Bioprocessing and Bioproducts Engineering Laboratory, Department of Biological Systems Engineering, Washington State University, Pullman, WA (United States)

    2014-06-19

    Today’s biotechnologists seek new biocatalysts to meet the growing demand for the bioproducts. This review critically evaluates the potential use of Y. lipolytica as an oleaginous cell factory platform. This yeast has undergone extensive modifications for converting a wide range of hydrophobic and hydrophilic biomass, including alkane, oil, glycerol, and sugars to fatty acid-based products. This article highlights challenges in the development of this platform and provides an overview of strategies to enhance its potential in the sustainable production of biodiesel, functional dietary lipid compounds, and other value-added oleochemical compounds. Future applications of the recombinant Y. lipolytica platform are also discussed.

  18. Analysis of the vertebral venous system in relation to cerebral venous drainage on MR angiography

    International Nuclear Information System (INIS)

    Baik, Seung Kug; Sohn, Chul Ho; Kim, Gab Chul; Kim, Yong Sun

    2004-01-01

    In the supine position, cerebral venous drainage occurs primarily through the internal jugular veins, as seen on venous phase cerebral angiography. However, in the erect position, the vertebral venous system represents the major alternative pathway of cerebral venous drainage, while outflow through the internal jugular veins is absent or negligible. The purpose of this study is to evaluate the vertebral venous system and its relationship between the surrounding venous structures using magnetic resonance angiography (MRA) in the case of subjects in the supine position. We retrospectively reviewed the results of 65 patients (M:F = 31: 34, mean age 61.6 years) who underwent multi-phase contrast-enhanced carotid MRA. The imaging studies were performed using a 3.0 T MR unit (TR: 5.2, TE: 1.1, FA: 20, 3.8 thickness, EC: 1). We analyzed the appearance and extent of the vertebral venous system (vertebral venous plexus and vertebral artery venous plexus) and the internal jugular vein on the venous phase images. We also evaluated the main drainage pattern of the cerebral venous drainage and the drainage pattern of the vertebral venous system. The visualized vertebral venous system was defined as either poor, vertebral venous plexus dominant, vertebral artery venous plexus dominant or mixed. In the vertebral venous system, the vertebral artery venous plexus was visualized in 54 cases (83%). The appearance of the visualized vertebral artery venous plexus was symmetrical in 39 cases (72%) and asymmetrical in 15 cases (28%). The extent of the visualized vertebral artery venous plexus was partial in 26 cases (48%) and complete in 28 cases (52%). The vertebral venous plexus was visualized in 62 cases (95%). The appearance of the visualized vertebral artery venous plexus was symmetrical in 43 cases (69%) and asymmetrical in 19 cases (31%). The extent of the visualized vertebral artery venous plexus was partial in 35 cases (56%) and complete in 27 cases (44%). The appearance of the

  19. Femoral venous oxygen saturation is no surrogate for central venous oxygen saturation

    NARCIS (Netherlands)

    van Beest, Paul A.; van der Schors, Alice; Liefers, Henriëtte; Coenen, Ludo G. J.; Braam, Richard L.; Habib, Najib; Braber, Annemarije; Scheeren, Thomas W. L.; Kuiper, Michaël A.; Spronk, Peter E.

    2012-01-01

    Objective: The purpose of our study was to determine if central venous oxygen saturation and femoral venous oxygen saturation can be used interchangeably during surgery and in critically ill patients. Design: Prospective observational controlled study. Setting: Nonacademic university-affiliated

  20. Clinicoroentgenological diagnosis of chronic venous ovarian insufficiency

    International Nuclear Information System (INIS)

    Grakova, L.S.; Galkin, E.V.; Naumova, E.B.

    1989-01-01

    The paper is devoted to clinicoroentgenological correlations of venous renogonadal hemodynamics in 168 women of reproductive age (151 women with infertility, habitual abortion, disordered menstrual function and 17 patients without disorders of the reproductive tract). Clinicolaboratory investigation was followed by visceral and parietal flebography for the detection of a pathological venous reflux into the ovarian pampiniform plexus. Clinicoroentgenological semiotics of chronic venous ovarian insufficiency was analyzed. Infertility was shown to be the main clinical manifestation of ovarian varicocele

  1. Sonographic detection of portal venous gas

    International Nuclear Information System (INIS)

    Lee, Wang Yul; Lee, S. K.; Cho, O. K.

    1989-01-01

    Portal venous gas suggests underlying bowel disease such as strangulating intestinal obstruction and its demonstration carries with it an important implications with respect to patient management. Radiography has been the gold standard for the detection of portal venous gas. We have experienced two cases of portal venous gas diagnosed by ultrasound. Sonographic findings were floating echoes in the main portal vein and highly echogenic linear or patchy echoes within the hepatic parenchyma. Simple abdominal films of those cases failed to demonstrate gas in the portal venous system

  2. Converter topologies and control

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Fernando; Qin, Hengsi; Chapman, Patrick

    2018-05-01

    An inverter includes a transformer that includes a first winding, a second winding, and a third winding, a DC-AC inverter electrically coupled to the first winding of the transformer, a cycloconverter electrically coupled to the second winding of the transformer, an active filter electrically coupled to the third winding of the transformer. The DC-AC inverter is adapted to convert the input DC waveform to an AC waveform delivered to the transformer at the first winding. The cycloconverter is adapted to convert an AC waveform received at the second winding of the transformer to the output AC waveform having a grid frequency of the AC grid. The active filter is adapted to sink and source power with one or more energy storage devices based on a mismatch in power between the DC source and the AC grid.

  3. Converting high boiling hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Terrisse, H; DuFour, L

    1929-02-12

    A process is given for converting high boiling hydrocarbons into low boiling hydrocarbons, characterized in that the high boiling hydrocarbons are heated to 200 to 500/sup 0/C in the presence of ferrous chloride and of such gases as hydrogen, water gas, and the like gases under a pressure of from 5 to 40 kilograms per square centimeter. The desulfurization of the hydrocarbons occurs simultaneously.

  4. Advanced converters and reactors

    International Nuclear Information System (INIS)

    Haefele, W.; Kessler, G.

    1984-01-01

    As Western Europe and most countries of the Asia-Pacific region (except Australia) have only small natural uranium resources, they must import nuclear fuel from the major uranium supplier countries. The introduction of advanced converter and breeder reactor technology allows a fuel utilization of a factor of 4 to 100 higher than with present low converters (LWRs) and will make uranium-importing countries less vulnerable to price jumps and supply stops in the uranium market. In addition, breeder-reactor technology will open up a potential that can cover world energy requirements for several thousand years. The enormous development costs of advanced converter and breeder technologies can probably be raised only by highly industrialized countries. Those highly industrialized countries that have little or no uranium resources (Western Europe, Japan) will probably be the first to introduce this advanced reactor technology on a commercial scale. A number of small countries and islands will need only small power reactors with inherent safety capabilities, especially in the beginning of their nuclear energy programs. For economic reasons, the fuel cycle services should come from large reprocessing centers of countries having sufficiently large nuclear power programs or from international fuel cycle centers. (author)

  5. Hyperthyroidism and cerebral venous thrombosis.

    Science.gov (United States)

    Mouton, S; Nighoghossian, N; Berruyer, M; Derex, L; Philippeau, F; Cakmak, S; Honnorat, J; Hermier, M; Trouillas, P

    2005-01-01

    The demonstration of an underlying prothrombotic condition in cerebral venous thrombosis (CVT) may have important practical consequences in terms of prevention. Thyrotoxicosis through a hypercoagulable state may be a predisposing factor for CVT. The authors present the cases of 4 patients who developed CVT and hyperthyroidism. At the acute stage, hyperthyroidism was associated with an increase in factor VIII (FVIII). At follow-up, FVIII level remained increased in 2 patients. Hyperthyroidism may have an impact on FVIII level. Accordingly in patients with hyperthyroidism and neurological symptoms, the diagnosis of CVT should be considered and an exhaustive coagulation screening may be appropriate. (c) 2005 S. Karger AG, Basel.

  6. Acid-base characteristics of powdered-activated-carbon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Reed, B.E. (West Virginia Univ., Morgantown (United States)); Jensen, J.N.; Matsumoto, M.R. (State Univ. of New York, Buffalo (United States))

    Adsorption of heavy metals onto activated carbon has been described using the surface-complex-formation (SCF) model, a chemical equilibrium model. The SCF model requires a knowledge of the amphoteric nature of activated carbon prior to metal adsorption modeling. In the past, a single-diprotic-acid-site model had been employed to describe the amphoteric nature of activated-carbon surfaces. During this study, the amphoteric nature of two powdered activated carbons were investigated, and a three-monoprotic site surface model was found to be a plausible alternative. The single-diprotic-acid-site and two-monoprotic-site models did not describe the acid-base behavior of the two carbons studied adequately. The two-diprotic site was acceptable for only one of the study carbons. The acid-base behavior of activated carbon surfaces seem to be best modeled as a series of weak monoprotic acids.

  7. Convertible bond valuation focusing on Chinese convertible bond market

    OpenAIRE

    Yang, Ke

    2010-01-01

    This paper mainly discusses the methods of valuation of convertible bonds in Chinese market. Different from common convertible bonds in European market, considering the complicate features of Chinese convertible bond, this paper represents specific pricing approaches for pricing convertible bonds with different provisions along with the increment of complexity of these provisions. More specifically, this paper represents the decomposing method and binomial tree method for pricing both of Non-...

  8. Acid-base disturbance in patients with cirrhosis

    DEFF Research Database (Denmark)

    Henriksen, Jens H; Bendtsen, Flemming; Møller, Søren

    2015-01-01

    (r=-0.25, Psodium (r=-0.38, Preduced standard base excess in all patients (P...PURPOSE: Acid-base disturbances were investigated in patients with cirrhosis in relation to hemodynamic derangement to analyze the hyperventilatory effects and the metabolic compensation. METHODS: A total of 66 patients with cirrhosis and 44 controls were investigated during a hemodynamic study......, and effects of unidentified ions (all P

  9. A fully automatic system for acid-base coulometric titrations

    OpenAIRE

    Cladera, A.; Caro, A.; Estela, J. M.; Cerdà, V.

    1990-01-01

    An automatic system for acid-base titrations by electrogeneration of H+ and OH- ions, with potentiometric end-point detection, was developed. The system includes a PC-compatible computer for instrumental control, data acquisition and processing, which allows up to 13 samples to be analysed sequentially with no human intervention. The system performance was tested on the titration of standard solutions, which it carried out with low errors and RSD. It was subsequently applied to the analysis o...

  10. Effects of acid-base imbalance on vascular reactivity

    Directory of Open Access Journals (Sweden)

    A.C. Celotto

    2008-06-01

    Full Text Available Acid-base homeostasis maintains systemic arterial pH within a narrow range. Whereas the normal range of pH for clinical laboratories is 7.35-7.45, in vivo pH is maintained within a much narrower range. In clinical and experimental settings, blood pH can vary in response to respiratory or renal impairment. This altered pH promotes changes in vascular smooth muscle tone with impact on circulation and blood pressure control. Changes in pH can be divided into those occurring in the extracellular space (pHo and those occurring within the intracellular space (pHi, although, extracellular and intracellular compartments influence each other. Consistent with the multiple events involved in the changes in tone produced by altered pHo, including type of vascular bed, several factors and mechanisms, in addition to hydrogen ion concentration, have been suggested to be involved. The scientific literature has many reports concerning acid-base balance and endothelium function, but these concepts are not clear about acid-base disorders and their relations with the three known mechanisms of endothelium-dependent vascular reactivity: nitric oxide (NO/cGMP-dependent, prostacyclin (PGI2/cAMP-dependent and hyperpolarization. During the last decades, many studies have been published and have given rise to confronting data on acid-base disorder and endothelial function. Therefore, the main proposal of this review is to provide a critical analysis of the state of art and incentivate researchers to develop more studies about these issues.

  11. [Acid-base status in patients treated with peritoneal dialysis].

    Science.gov (United States)

    Katalinić, Lea; Blaslov, Kristina; Pasini, Eva; Kes, Petar; Bašić-Jukić, Nikolina

    2014-04-01

    When compared to hemodialysis, peritoneal dialysis is very simple yet low cost method of renal replacement therapy. Series of studies have shown its superiority in preserving residual renal function, postponing uremic complications, maintaining the acid-base balance and achieving better post-transplant outcome in patients treated with this method. Despite obvious advantages, its role in the treatment of chronic kidney disease is still not as important as it should be. Metabolic acidosis is an inevitable complication associated with progressive loss of kidney function. Its impact on mineral and muscle metabolism, residual renal function, allograft function and anemia is very complex but can be successfully managed. The aim of our study was to evaluate the efficiency in preserving the acid-base balance in patients undergoing peritoneal dialysis at Zagreb University Hospital Center. Twenty-eight patients were enrolled in the study. The mean time spent on the treatment was 32.39 ± 43.43 months. Only lactate-buffered peritoneal dialysis fluids were used in the treatment. Acid-base balance was completely maintained in 73.07% of patients; 11.54% of patients were found in the state of mild metabolic acidosis, and the same percentage of patients were in the state of mild metabolic alkalosis. In one patient, mixed alkalosis with respiratory and metabolic component was present. The results of this study showed that acid-base balance could be maintained successfully in patients undergoing peritoneal dialysis, even only with lactate-buffered solutions included in the treatment, although they were continuously proclaimed as inferior in comparison with bicarbonate-buffered ones. In well educated and informed patients who carefully use this method, accompanied by the attentive and thorough care of their physicians, this method can provide quality continuous replacement of lost renal function as well as better quality of life.

  12. Electrochemistry of acid-base reactions in anhydrous hydrogen fluoride

    International Nuclear Information System (INIS)

    Masson, J.P.; Devynck, J.; Tremillon, B.

    1975-01-01

    Electrochemical studies were made in following media: water-HF mixtures, anhydrous HF and KF solutions in HF, solutions of the SbF5 type in HF. The acidity level of these solutions was evaluated using the R(H) functions based on the strehlow hypotheses. From the pH measurement in anhydrous HF, it was possible to get acid-base titration curves and pH buffers. The behavior of quinones in anhydrous HF is presented [fr

  13. Neurologic complications of electrolyte disturbances and acid-base balance.

    Science.gov (United States)

    Espay, Alberto J

    2014-01-01

    Electrolyte and acid-base disturbances are common occurrences in daily clinical practice. Although these abnormalities can be readily ascertained from routine laboratory findings, only specific clinical correlates may attest as to their significance. Among a wide phenotypic spectrum, acute electrolyte and acid-base disturbances may affect the peripheral nervous system as arreflexic weakness (hypermagnesemia, hyperkalemia, and hypophosphatemia), the central nervous system as epileptic encephalopathies (hypomagnesemia, dysnatremias, and hypocalcemia), or both as a mixture of encephalopathy and weakness or paresthesias (hypocalcemia, alkalosis). Disabling complications may develop not only when these derangements are overlooked and left untreated (e.g., visual loss from intracranial hypertension in respiratory or metabolic acidosis; quadriplegia with respiratory insufficiency in hypermagnesemia) but also when they are inappropriately managed (e.g., central pontine myelinolisis when rapidly correcting hyponatremia; cardiac arrhythmias when aggressively correcting hypo- or hyperkalemia). Therefore prompt identification of the specific neurometabolic syndromes is critical to correct the causative electrolyte or acid-base disturbances and prevent permanent central or peripheral nervous system injury. This chapter reviews the pathophysiology, clinical investigations, clinical phenotypes, and current management strategies in disorders resulting from alterations in the plasma concentration of sodium, potassium, calcium, magnesium, and phosphorus as well as from acidemia and alkalemia. © 2014 Elsevier B.V. All rights reserved.

  14. Carbonic anhydrase 5 regulates acid-base homeostasis in zebrafish.

    Directory of Open Access Journals (Sweden)

    Ruben Postel

    Full Text Available The regulation of the acid-base balance in cells is essential for proper cellular homeostasis. Disturbed acid-base balance directly affects cellular physiology, which often results in various pathological conditions. In every living organism, the protein family of carbonic anhydrases regulate a broad variety of homeostatic processes. Here we describe the identification, mapping and cloning of a zebrafish carbonic anhydrase 5 (ca5 mutation, collapse of fins (cof, which causes initially a collapse of the medial fins followed by necrosis and rapid degeneration of the embryo. These phenotypical characteristics can be mimicked in wild-type embryos by acetazolamide treatment, suggesting that CA5 activity in zebrafish is essential for a proper development. In addition we show that CA5 regulates acid-base balance during embryonic development, since lowering the pH can compensate for the loss of CA5 activity. Identification of selective modulators of CA5 activity could have a major impact on the development of new therapeutics involved in the treatment of a variety of disorders.

  15. Acid-base transport by the renal proximal tubule.

    Science.gov (United States)

    Skelton, Lara A; Boron, Walter F; Zhou, Yuehan

    2010-01-01

    Each day, the kidneys filter 180 L of blood plasma, equating to some 4,300 mmol of the major blood buffer, bicarbonate (HCO3-). The glomerular filtrate enters the lumen of the proximal tubule (PT), and the majority of filtered HCO3- is reclaimed along the early (S1) and convoluted (S2) portions of the PT in a manner coupled to the secretion of H+ into the lumen. The PT also uses the secreted H+ to titrate non-HCO3- buffers in the lumen, in the process creating "new HCO3-" for transport into the blood. Thus, the PT - along with more distal renal segments - is largely responsible for regulating plasma [HCO3-]. In this review we first focus on the milestone discoveries over the past 50+ years that define the mechanism and regulation of acid-base transport by the proximal tubule. Further on in the review, we will summarize research still in progress from our laboratory, work that addresses the problem of how the PT is able to finely adapt to acid-base disturbances by rapidly sensing changes in basolateral levels of HCO3- and CO2 (but not pH), and thereby to exert tight control over the acid-base composition of the blood plasma.

  16. Pulmonary venous abnormalities encountered on pre ...

    African Journals Online (AJOL)

    Multidetector computed tomography (MDCT) elegantly renders pulmonary venous anatomy. With increasing numbers of radiofrequency ablation procedures being performed, there is now a greater emphasis on pre-procedure imaging to delineate this anatomy. Pulmonary venous mapping studies can be performed with or ...

  17. REVIEW ARTICLE Venous thromboembolism associated with ...

    Indian Academy of Sciences (India)

    Navya

    2017-03-24

    Mar 24, 2017 ... Venous thromboembolism associated with protein S deficiency due to ... 2 Institute of Cardiology, Jagiellonian University Medical College, Kraków, Poland ... It has been long recognized that reduced PS activity is a risk factor for venous ... 1988). Sequencing of PROS1 gene intensified studies of genotype-.

  18. Sex-specific aspects of venous thrombosis

    NARCIS (Netherlands)

    Roach, Rachel Elizabeth Jo

    2014-01-01

    Venous thrombosis is a disease that occurs in 1-2 per 1000 people per year. At the time of their first venous thrombosis, approximately 50% of women are exposed to reproductive risk factors (oral contraception, postmenopausal hormone therapy, pregnancy and the puerperium). In this thesis, we showed

  19. Venous Thromboembolism in Patients With Thrombocytopenia

    DEFF Research Database (Denmark)

    Bælum, Jens Kristian; Ellingsen Moe, Espen; Nybo, Mads

    2017-01-01

    BACKGROUND: Venous thromboembolism (VTE) is a frequent and potentially lethal condition. Venous thrombi are mainly constituted of fibrin and red blood cells, but platelets also play an important role in VTE formation. Information about VTE in patients with thrombocytopenia is, however, missing. O...... having thrombocytopenia with VTE seem to be safely treated with anticoagulants without increased occurrence of bleeding....

  20. Risk factors for venous thromboembolism during pregnancy

    DEFF Research Database (Denmark)

    Jensen, Thomas Bo; Gerds, Thomas Alexander; Grøn, Randi

    2013-01-01

    Pregnant women are at an increased risk of venous thromboembolism (VTE). Risk factors for VTE among pregnant women are not sufficiently investigated.......Pregnant women are at an increased risk of venous thromboembolism (VTE). Risk factors for VTE among pregnant women are not sufficiently investigated....

  1. Clinical quality indicators of venous leg ulcers

    DEFF Research Database (Denmark)

    Kjaer, Monica L; Mainz, Jan; Soernsen, Lars T

    2005-01-01

    In the clinical setting, diagnosis and treatment of venous leg ulcers can vary considerably from patient to patient. The first step to reducing this variation is to document venous leg ulcer care through use of quantitative scientific documentation principles. This requires the development of val...

  2. A BMPy Road for Venous Development.

    Science.gov (United States)

    Goddard, Lauren M; Kahn, Mark L

    2017-09-11

    Detailed molecular pathways for the specific growth of arteries and lymphatic vessels have been identified, but the mechanisms controlling venous vessel growth have been obscure. Tischfield and colleagues (2017) shed new light on this problem by identifying a role for BMP signaling in development of the cerebral venous system. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Does acid-base equilibrium correlate with remnant liver volume during stepwise liver resection?

    Science.gov (United States)

    Golriz, Mohammad; Abbasi, Sepehr; Fathi, Parham; Majlesara, Ali; Brenner, Thorsten; Mehrabi, Arianeb

    2017-10-01

    Small for size and flow syndrome (SFSF) is one of the most challenging complications following extended hepatectomy (EH). After EH, hepatic artery flow decreases and portal vein flow increases per 100 g of remnant liver volume (RLV). This causes hypoxia followed by metabolic acidosis. A correlation between acidosis and posthepatectomy liver failure has been postulated but not studied systematically in a large animal model or clinical setting. In our study, we performed stepwise liver resections on nine pigs to defined SFSF limits as follows: step 1: segment II/III resection, step 2: segment IV resection, step 3: segment V/VIII resection (RLV: 75, 50, and 25%, respectively). Blood gas values were measured before and after each step using four catheters inserted into the carotid artery, internal jugular vein, hepatic artery, and portal vein. The pH, [Formula: see text], and base excess (BE) decreased, but [Formula: see text] values increased after 75% resection in the portal and jugular veins. EH correlated with reduced BE in the hepatic artery. Pco 2 values increased after 75% resection in the jugular vein. In contrast, arterial Po 2 increased after every resection, whereas the venous Po 2 decreased slightly. There were differences in venous [Formula: see text], BE in the hepatic artery, and Pco 2 in the jugular vein after 75% liver resection. Because 75% resection is the limit for SFSF, these noninvasive blood evaluations may be used to predict SFSF. Further studies with long-term follow-up are required to validate this correlation. NEW & NOTEWORTHY This is the first study to evaluate acid-base parameters in major central and hepatic vessels during stepwise liver resection. The pH, [Formula: see text], and base excess (BE) decreased, but [Formula: see text] values increased after 75% resection in the portal and jugular veins. Extended hepatectomy correlated with reduced BE in the hepatic artery. Because 75% resection is the limit for small for size and flow

  4. Acid-base disorders in calves with chronic diarrhea.

    Science.gov (United States)

    Bednarski, M; Kupczyński, R; Sobiech, P

    2015-01-01

    The aim of this study was to analyze disorders of acid-base balance in calves with chronic diarrhea caused by mixed, viral, bacterial and Cryptosporydium parvum infection. We compared results ob- tained with the classic model (Henderson-Hasselbalch) and strong ion approach (the Steward model). The study included 36 calves aged between 14 and 21 days. The calves were allocated to three groups: I - (control) non-diarrheic calves, group II - animals with compensated acid-base imbalance and group III calves with compensated acid-base disorders and hypoalbuminemia. Plasma concentrations of Na+, K+, Cl-, C12+, Mg2+, P, albumin and lactate were measured. In the classic model, acid-base balance was determined on the basis of blood pH, pCO2, HCO3-, BE and anion gap. In the strong ion model, strong ion difference (SID), effective strong anion difference, total plasma concentration of nonvolatile buffers (A(Tot)) and strong ion gap (SIG) were measured. The control calves and the animals from groups II and III did not differ significantly in terms of their blood pH. The plasma concentration of HCO3-, BE and partial pressure of CO2 in animals from the two groups with chronic diarrhea were significantly higher than those found in the controls. The highest BE (6.03 mmol/l) was documented in calves from group II. The animals from this group presented compensation resulted from activation of metabolic mechanisms. The calves with hypoal- buminemia (group III) showed lower plasma concentrations of albumin (15.37 g/L), Cl (74.94 mmol/L), Mg2+ (0.53 mmol/L), P (1.41 mmol/L) and higher value of anion gap (39.03 mmol/L). This group III presented significantly higher SID3 (71.89 mmol/L), SID7 (72.92 mmol/L) and SIG (43.53 mmol/L) values than animals from the remaining groups (P acid-base disturbance in these cases suggests that classic model have some limitations. This model can not be recommended for use whenever serum albumin or phosphate concentrations are markedly abnormal.

  5. The normal acid-base status of mice.

    Science.gov (United States)

    Iversen, Nina K; Malte, Hans; Baatrup, Erik; Wang, Tobias

    2012-03-15

    Rodent models are commonly used for various physiological studies including acid-base regulation. Despite the widespread use of especially genetic modified mice, little attention have been made to characterise the normal acid-base status in these animals in order to reveal proper control values. Furthermore, several studies report blood gas values obtained in anaesthetised animals. We, therefore, decided to characterise blood CO(2) binding characteristic of mouse blood in vitro and to characterise normal acid-base status in conscious BALBc mice. In vitro CO(2) dissociation curves, performed on whole blood equilibrated to various PCO₂ levels in rotating tonometers, revealed a typical mammalian pK' (pK'=7.816-0.234 × pH (r=0.34)) and a non-bicarbonate buffer capacity (16.1 ± 2.6 slyke). To measure arterial acid-base status, small blood samples were taken from undisturbed mice with indwelling catheters in the carotid artery. In these animals, pH was 7.391 ± 0.026, plasma [HCO(3)(-)] 18.4 ± 0.83 mM, PCO₂ 30.3 ± 2.1 mm Hg and lactate concentration 4.6 ± 0.7 mM. Our study, therefore, shows that mice have an arterial pH that resembles other mammals, although arterial PCO₂ tends to be lower than in larger mammals. However, pH from arterial blood sampled from mice anaesthetised with isoflurane was significantly lower (pH 7.239 ± 0.021), while plasma [HCO(3)(-)] was 18.5 ± 1.4 mM, PCO₂ 41.9 ± 2.9 mm Hg and lactate concentration 4.48 ± 0.67 mM. Furthermore, we measured metabolism and ventilation (V(E)) in order to determine the ventilation requirements (VE/VO₂) to answer whether small mammals tend to hyperventilate. We recommend, therefore, that studies on acid-base regulation in mice should be based on samples taken for indwelling catheters rather than cardiac puncture of terminally anaesthetised mice. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. X-Y Converter Family

    DEFF Research Database (Denmark)

    Bhaskar, Mahajan Sagar; Sanjeevikumar, Padmanaban; Wheeler, Patrick

    2016-01-01

    A New breed of a buck boost converter, named as the XY converter family is proposed in this article. In the XY family, 16 topologies are presented which are highly suitable for renewable energy applications which require a high ratio of DC-DC converter; such as a photovoltaic multilevel inverter...... system, high voltage automotive applications and industrial drives. Compared to the traditional boost converter and existing recent converters, the proposed XY converter family has the ability to provide a higher output voltage by using less number of power devices and reactive components. Other distinct...... features of the XY converter family are i) Single control switch ii) Provide negative output voltage iii) Non-isolated topologies iv) High conversion ratio without making the use of high duty cycle and v) modular structure. XY family is compared with the recent high step-up converters and the detailed...

  7. Resonant power converters

    CERN Document Server

    Kazimierczuk, Marian K

    2012-01-01

    This book is devoted to resonant energy conversion in power electronics. It is a practical, systematic guide to the analysis and design of various dc-dc resonant inverters, high-frequency rectifiers, and dc-dc resonant converters that are building blocks of many of today's high-frequency energy processors. Designed to function as both a superior senior-to-graduate level textbook for electrical engineering courses and a valuable professional reference for practicing engineers, it provides students and engineers with a solid grasp of existing high-frequency technology, while acquainting them wit

  8. Cycloidal Wave Energy Converter

    Energy Technology Data Exchange (ETDEWEB)

    Stefan G. Siegel, Ph.D.

    2012-11-30

    This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will

  9. Leukocytic Response and Peripheral Venous Blood Lymphocyte Apoptosis as a Marker of Tissue Ischemia in Acute Massive Blood Loss

    Directory of Open Access Journals (Sweden)

    N. V. Borovkova

    2013-01-01

    Full Text Available Objective: to estimate the level of peripheral venous blood lymphocyte apoptosis and intraoperative hypoxia in victims with acute massive blood loss. Subjects and methods. Twenty-two patients with open and close chest and abdominal traumas complicated by acute massive blood loss were examined. All the patients were emergently operated on to stop bleeding. Tissue metabolism was evaluated from gases, acid-base parameters, and plasma lactate, glucose, potassium, and sodium levels. Apoptosis of mononuclear cells was studied and dead leukocytes were counted using flow cytometry. Results. Preoperatively, the victims were found to have venous hypoxemia, hyperlactatemia, hyperglycemia, moderate leukocytosis, and higher dead leukocyte counts. There were also raised counts of lymphocytes coming into the process of apoptosis. A significant relationship was found between monocyte counts and hypoxia values. At the end of surgery, oxygen balance values became stable and exerted an effect on the count of leukocytes, the relative level of granulocytes, the relative and absolute counts of dead and damaged leukocytes, and the concentration of lymphocytes in the victims’ venous blood during the early stages of apoptosis, as evidenced by nonlinear regression models. Conclusion. The indicators of immunocompetent cell apoptosis and the count of venous blood dead leukocytes along with lactate levels and venous hypoxemia parameters reflect the degree of tissue hypoxia and may be used as specific markers.

  10. [Materno-fetal acid-base equilibrium evaluation in parturients submitted to ketamine anesthesia (author's transl)].

    Science.gov (United States)

    Mauad Filho, F; Meirelles, R S

    1975-01-01

    In the present work ketamine was used as anesthetic during the labor in order to evaluate the effect of this anesthetic on the binominal fetus-mother. Two groups of parturients and their fetuses, were studied: 1) The experimental group, with 22 parturients and their fetuses submitted to ketamine anesthesia during the labord, and 2) The control group, with 20 parturients and their fetuses without any analgesic treatment during the labor. In 20 cases of the experimental group the anesthetic was injected during the delivery labor and the other two just before it. It were evaluated in the mother's blood the biochemical parameters of the acid-base balance and others collateral effects of the anesthesia; on the fetus's side the same parameters also and the cardiac frequency. The newborn were evaluated by Apgar Score during the first and fifth minutes of life. The incidence of the spontaneous delivery in the experimental group, was 78%; in 22% of these patients the forceps of relief was used. In 22 cases in which Ketamine was applied it were observed, the following events: elevation of the blood pressure (50%), perineum rigidness (18%), dreams and or hallucinations (18%), increase of the cardiac frequency (9%), apneia (4%) and nausea (4%). It was also observed an increase of uterine tonus an abolishment of abdominal press during the delivery labor, studied through the uterine electromyography register. It was noted after the Ketamine application a fall in the pH of the maternal peripherical venous blood, fetal skull blood and the pH of the blood of the umbilical vein. 22% of the newborns, from the experimental group, presented a depression in the first minute of life (Apgar less than or equals to 6). The pCO2 values in the blood of the umbilical artery were higher in the experimental group than in the control one.

  11. [Venous catheter-related infections].

    Science.gov (United States)

    Ferrer, Carmen; Almirante, Benito

    2014-02-01

    Venous catheter-related infections are a problem of particular importance, due to their frequency, morbidity and mortality, and because they are potentially preventable clinical processes. At present, the majority of hospitalized patients and a considerable number of outpatients are carriers of these devices. There has been a remarkable growth of knowledge of the epidemiology of these infections, the most appropriate methodology for diagnosis, the therapeutic and, in particular, the preventive strategies. Multimodal strategies, including educational programs directed at staff and a bundle of simple measures for implementation, applied to high-risk patients have demonstrated great effectiveness for their prevention. In this review the epidemiology, the diagnosis, and the therapeutic and preventive aspects of these infections are updated. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  12. Acid-base properties of Baltic Sea dissolved organic matter

    Science.gov (United States)

    Hammer, Karoline; Schneider, Bernd; Kuliński, Karol; Schulz-Bull, Detlef E.

    2017-09-01

    Calculations related to the marine CO2 system that are based on alkalinity data may be strongly biased if the contributions of organic compounds are ignored. In coastal seas, concentrations of dissolved organic matter (DOM) are frequently high and alkalinity from inorganic compounds is low. In this study, based on measurements of total alkalinity, total CO2, and pH, we determined the organic alkalinity, Aorg, in water from the central Baltic Sea. The maximum Aorg measured in the surface mixed layer during the spring bloom was > 50 μmol/kg-SW but the Aorg decreased with depth and approached zero below the permanent halocline. This behavior could be attributed to the decreased pH of deeper water layers. The data were used to calculate the bulk dissociation constant, KDOM, for marine DOM and the fraction f of dissolved organic carbon (DOC) that acts as a carrier for acid-base functional groups. The p KDOM (7.27) agreed well with the value (7.34) previously estimated in a preliminary study of organic alkalinity in the Baltic Sea. The fraction of carbon atoms carrying acid-base groups was 17% and was somewhat higher than previously reported (12%). Spike experiments performed using artificial seawater and three different humic/fulvic substances tested whether the acid-base properties of these substances explain the results of our field study. Specifically, Aorg was determined at different concentrations (DOC) of the added humic/fulvic substances. The relationship between Aorg and the DOC concentrations indicated that humic/fulvic substances are more acidic (p KDOM < 6.5) than the bulk DOC natural occurring in the Baltic Sea.

  13. Developing nucleic acid-based electrical detection systems

    Directory of Open Access Journals (Sweden)

    Gabig-Ciminska Magdalena

    2006-03-01

    Full Text Available Abstract Development of nucleic acid-based detection systems is the main focus of many research groups and high technology companies. The enormous work done in this field is particularly due to the broad versatility and variety of these sensing devices. From optical to electrical systems, from label-dependent to label-free approaches, from single to multi-analyte and array formats, this wide range of possibilities makes the research field very diversified and competitive. New challenges and requirements for an ideal detector suitable for nucleic acid analysis include high sensitivity and high specificity protocol that can be completed in a relatively short time offering at the same time low detection limit. Moreover, systems that can be miniaturized and automated present a significant advantage over conventional technology, especially if detection is needed in the field. Electrical system technology for nucleic acid-based detection is an enabling mode for making miniaturized to micro- and nanometer scale bio-monitoring devices via the fusion of modern micro- and nanofabrication technology and molecular biotechnology. The electrical biosensors that rely on the conversion of the Watson-Crick base-pair recognition event into a useful electrical signal are advancing rapidly, and recently are receiving much attention as a valuable tool for microbial pathogen detection. Pathogens may pose a serious threat to humans, animal and plants, thus their detection and analysis is a significant element of public health. Although different conventional methods for detection of pathogenic microorganisms and their toxins exist and are currently being applied, improvements of molecular-based detection methodologies have changed these traditional detection techniques and introduced a new era of rapid, miniaturized and automated electrical chip detection technologies into pathogen identification sector. In this review some developments and current directions in

  14. Acid-base transport in pancreas-new challenges

    DEFF Research Database (Denmark)

    Novak, Ivana; Haanes, Kristian Agmund; Wang, Jing

    2013-01-01

    Along the gastrointestinal tract a number of epithelia contribute with acid or basic secretions in order to aid digestive processes. The stomach and pancreas are the most extreme examples of acid (H+) and base (HCO-3) transporters, respectively. Nevertheless, they share the same challenges...... to consider in pancreas are the proton pumps (H-K-ATPases), as well as the calcium-activated K and Cl channels, such as K3.1 and TMEM16A/ANO1. Local regulators, such as purinergic signaling, fine-tune, and coordinate pancreatic secretion. Lastly, we speculate whether dys-regulation of acid-base transport...

  15. Modelling of acid-base titration curves of mineral assemblages

    Directory of Open Access Journals (Sweden)

    Stamberg Karel

    2016-01-01

    Full Text Available The modelling of acid-base titration curves of mineral assemblages was studied with respect to basic parameters of their surface sites to be obtained. The known modelling approaches, component additivity (CA and generalized composite (GC, and three types of different assemblages (fucoidic sandstones, sedimentary rock-clay and bentonite-magnetite samples were used. In contrary to GC-approach, application of which was without difficulties, the problem of CA-one consisted in the credibility and accessibility of the parameters characterizing the individual mineralogical components.

  16. Advances in nucleic acid-based diagnostics of bacterial infections

    DEFF Research Database (Denmark)

    Barken, Kim Bundvig; Haagensen, Janus Anders Juul; Tolker-Nielsen, Tim

    2007-01-01

    Methods for rapid detection of infectious bacteria and antimicrobial-resistant pathogens have evolved significantly over the last decade. Many of the new procedures are nucleic acid-based and replace conventional diagnostic methods like culturing which is time consuming especially with fastidious...... of these pathogens is important to isolate patients and prevent further spreading of the diseases. Newly developed diagnostic procedures are superior with respect to turnaround time, sensitivity and specificity. Methods like multiplex real time PCR and different array-based technologies offer the possibility...

  17. Itaconic acid based potential sorbent for uranium recovery

    International Nuclear Information System (INIS)

    Kalyan, Y.; Naidu, G.R.K.; Das, Sadananda; Pandey, A.K.; Reddy, A.V.R.

    2010-01-01

    Cross-linked hydrogels and adsorptive membranes containing Itaconic acid, Acrylamide, Penta erythritol tetra acrylate and α, α-dimethyl- α-phenyl aceto phenone were prepared by UV-initiated bulk polymerization. These hydrogels and adsorptive membranes were characterized for pH uptake, sorption and desorption kinetics and selectivity towards uranium. The sorption ability of the sorbents towards uranyl ion was thoroughly examined. The developed itaconic acid based sorbents were evaluated for the recovery of uranium from lean sources like sea water. (author)

  18. Acid-base equilibria inside amine-functionalized mesoporous silica.

    Science.gov (United States)

    Yamaguchi, Akira; Namekawa, Manato; Kamijo, Toshio; Itoh, Tetsuji; Teramae, Norio

    2011-04-15

    Acid-base equilibria and effective proton concentration inside a silica mesopore modified with a trimethyl ammonium (TMAP) layer were studied by steady-state fluorescence experiments. The mesoporous silica with a dense TMAP layer (1.4 molecules/nm(2)) was prepared by a post grafting of N-trimethoxysilylpropyl-N,N,N-trimethylammonium at surfactant-templated mesoporous silica (diameter of silica framework =3.1 nm). The resulting TMAP-modified mesoporous silica strongly adsorbed of anionic fluorescence indicator dyes (8-hydroxypyrene-1,3,6-trisulfonate (pyranine), 8-aminopyrene-1,3,6-trisulfonate (APTS), 5,10,15,20-tetraphenyl-21H,23H-porphinetetrasulfonic acid disulfuric acid (TPPS), 2-naphthol-3,6-disulfonate (2NT)) and fluorescence excitation spectra of these dyes within TMAP-modified mesoporous silica were measured by varying the solution pH. The fluorescence experiments revealed that the acid-base equilibrium reactions of all pH indicator dyes within the TMAP-modified silica mesopore were quite different from those in bulk water. From the analysis of the acid-base equilibrium of pyranine, the following relationships between solution pH (pH(bulk)) and the effective proton concentration inside the pore (pH(pore)) were obtained: (1) shift of pH(pore) was 1.8 (ΔpH(pore)=1.8) for the pH(bulk) change from 2.1 to 9.1 (ΔpH(bulk)=7.0); (2) pH(pore) was not simply proportional to pH(bulk); (3) the inside of the TMAP-modified silica mesopore was suggested to be in a weak acidic or neutral condition when pH(bulk) was changed from 2.0 to 9.1. Since these relationships between pH(bulk) and pH(pore) could explain the acid-base equilibria of other pH indicator dyes (APTS, TPPS, 2NT), these relationships were inferred to describe the effective proton concentration inside the TMAP-modified silica mesopore. © 2011 American Chemical Society

  19. [Acid-base homeostasis: metabolic acidosis and metabolic alkalosis].

    Science.gov (United States)

    Dussol, Bertrand

    2014-07-01

    Acid-base homeostasis ensured by the kidneys, which maintain the equilibrium between proton generation by cellular metabolism and proton excretion in urine. This requirement is lifesaving because of the protons' ability to bind to anionic proteins in the extracellular space, modifying their structure and functions. The kidneys also regenerate bicarbonates. The kidney is not the sole organ in charge of maintaining blood pH in a very narrow range; lungs are also involved since they allow a large amount of volatile acid generated by cellular respiration to be eliminated. Copyright © 2014 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.

  20. Gas converter. Gaswandler

    Energy Technology Data Exchange (ETDEWEB)

    Eisenmann, A

    1984-09-27

    A gas converter is proposed for carbonisation gas containing hydrocarbons, consisting of a bricked shaft, which has a free combustion chamber and a solid bed of bulk grainy material with partly burnt hot carbonisation gases flowing through it as the lower boundary of this combustion chamber, in the upper part of which a hot reaction zone at about 1000 to 1200/sup 0/C is formed and which has a cracked gas extraction below the solid bed and an ash outlet. The solid bed is arranged at an angle to the vertical. The shaft has a solid material outlet for the bed material no longer capable of taking part in the reaction on the wall going obliquely downwards and a solid material inlet for new bulk bed material on the opposite wall going obliquely upwards.

  1. Electromagnetic wave energy converter

    Science.gov (United States)

    Bailey, R. L. (Inventor)

    1973-01-01

    Electromagnetic wave energy is converted into electric power with an array of mutually insulated electromagnetic wave absorber elements each responsive to an electric field component of the wave as it impinges thereon. Each element includes a portion tapered in the direction of wave propagation to provide a relatively wideband response spectrum. Each element includes an output for deriving a voltage replica of the electric field variations intercepted by it. Adjacent elements are positioned relative to each other so that an electric field subsists between adjacent elements in response to the impinging wave. The electric field results in a voltage difference between adjacent elements that is fed to a rectifier to derive dc output power.

  2. Power converters for ITER

    CERN Document Server

    Benfatto, I

    2006-01-01

    The International Thermonuclear Experimental Reactor (ITER) is a thermonuclear fusion experiment designed to provide long deuterium– tritium burning plasma operation. After a short description of ITER objectives, the main design parameters and the construction schedule, the paper describes the electrical characteristics of the French 400 kV grid at Cadarache: the European site proposed for ITER. Moreover, the paper describes the main requirements and features of the power converters designed for the ITER coil and additional heating power supplies, characterized by a total installed power of about 1.8 GVA, modular design with basic units up to 90 MVA continuous duty, dc currents up to 68 kA, and voltages from 1 kV to 1 MV dc.

  3. Cerebral venous outflow and cerebrospinal fluid dynamics

    Directory of Open Access Journals (Sweden)

    Clive B. Beggs

    2014-12-01

    Full Text Available In this review, the impact of restricted cerebral venous outflow on the biomechanics of the intracranial fluid system is investigated. The cerebral venous drainage system is often viewed simply as a series of collecting vessels channeling blood back to the heart. However there is growing evidence that it plays an important role in regulating the intracranial fluid system. In particular, there appears to be a link between increased cerebrospinal fluid (CSF pulsatility in the Aqueduct of Sylvius and constricted venous outflow. Constricted venous outflow also appears to inhibit absorption of CSF into the superior sagittal sinus. The compliance of the cortical bridging veins appears to be critical to the behaviour of the intracranial fluid system, with abnormalities at this location implicated in normal pressure hydrocephalus. The compliance associated with these vessels appears to be functional in nature and dependent on the free egress of blood out of the cranium via the extracranial venous drainage pathways. Because constricted venous outflow appears to be linked with increased aqueductal CSF pulsatility, it suggests that inhibited venous blood outflow may be altering the compliance of the cortical bridging veins.

  4. A Computer-Based Simulation of an Acid-Base Titration

    Science.gov (United States)

    Boblick, John M.

    1971-01-01

    Reviews the advantages of computer simulated environments for experiments, referring in particular to acid-base titrations. Includes pre-lab instructions and a sample computer printout of a student's use of an acid-base simulation. Ten references. (PR)

  5. Central venous catheters: the role of radiology

    International Nuclear Information System (INIS)

    Tan, P.L.; Gibson, M.

    2006-01-01

    The insertion and management of long-term venous catheters have long been the province of anaesthetists, intensive care physicians and surgeons. Radiologists are taking an increasing role in the insertion of central venous catheters (CVCs) because of their familiarity with the imaging equipment and their ability to manipulate catheters and guide-wires. The radiological management of the complications of CVCs has also expanded as a result. This article reviews the role of radiology in central venous access, covering the detection and management of their complications

  6. Integrated power electronic converters and digital control

    CERN Document Server

    Emadi, Ali; Nie, Zhong

    2009-01-01

    Non-isolated DC-DC ConvertersBuck ConverterBoost ConverterBuck-Boost ConverterIsolated DC-DC ConvertersFlyback ConverterForward ConverterPush-Pull ConverterFull-Bridge ConverterHalf-Bridge ConverterPower Factor CorrectionConcept of PFCGeneral Classification of PFC CircuitsHigh Switching Frequency Topologies for PFCApplication of PFC in Advanced Motor DrivesIntegrated Switched-Mode Power ConvertersSwitched-Mode Power SuppliesThe Concept of Integrated ConverterDefinition of Integrated Switched-Mode Power Supplies (ISMPS)Boost-Type Integrated TopologiesGeneral Structure of Boost-Type Integrated T

  7. Opuntia ficus indica (L.) Fruit Extract as Natural Indicator in Acid-Base Titration

    OpenAIRE

    Manoj A. Suva

    2014-01-01

    In routine experiments synthetic indicators are the choice of acid base titrations. But there are some limitations like environmental pollution, availability and higher cost which leads to search for natural compounds as an acid base indicator was started. The present work highlights theexploit of the methanolic and aqueous extract of the fruit of Opuntia ficus indica plants as a natural acid base indicator in acid base titrations. Opuntia ficus indica plant was identified and fruits were was...

  8. Acid base catalyzed transesterification kinetics of waste cooking oil

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Siddharth; Sharma, M.P.; Rajvanshi, Shalini [Alternate Hydro Energy Centre, Indian Institute of Technology, Roorkee (India)

    2011-01-15

    The present study reports the results of kinetics study of acid base catalyzed two step transesterification process of waste cooking oil, carried out at pre-determined optimum temperature of 65 C and 50 C for esterification and transesterification process respectively under the optimum condition of methanol to oil ratio of 3:7 (v/v), catalyst concentration 1%(w/w) for H{sub 2}SO{sub 4} and NaOH and 400 rpm of stirring. The optimum temperature was determined based on the yield of ME at different temperature. Simply, the optimum concentration of H{sub 2}SO{sub 4} and NaOH was determined with respect to ME Yield. The results indicated that both esterification and transesterification reaction are of first order rate reaction with reaction rate constant of 0.0031 min{sup -1} and 0.0078 min{sup -1} respectively showing that the former is a slower process than the later. The maximum yield of 21.50% of ME during esterification and 90.6% from transesterification of pretreated WCO has been obtained. This is the first study of its kind which deals with simplified kinetics of two step acid-base catalyzed transesterification process carried under the above optimum conditions and took about 6 h for complete conversion of TG to ME with least amount of activation energy. Also various parameters related to experiments are optimized with respect to ME yield. (author)

  9. An extremely sensitive monoboronic acid based fluorescent sensor for glucose

    International Nuclear Information System (INIS)

    Sun Xiangying; Liu Bin; Jiang Yunbao

    2004-01-01

    An extremely sensitive monoboronic acid based fluorescent sensor for glucose was developed. This was carried out by assembling a fluorescent monoboronic acid, 3-aminophenylboronic acid (PBA) indirectly onto gold surface via its electrostatic interaction with cysteine (Cys) that was directly assembled on the gold surface. The formation of self-assembled bilayers (SAB) was confirmed and primarily characterized by cyclic voltammetry and X-ray photoelectron spectra (XPS). The SAB containing PBA was found fluorescent and its fluorescence showed an extremely high sensitivity to the presence of glucose and other monosaccharides such as galactose and fructose with quenching constants at 10 8 M -1 order of magnitude compared to those at 10 2 M -1 in bulk solutions. The quenching constants were found to vary in the order of D-glucose>D-galactose>D-fructose>D-mannose that is different from that in bulk solution which shows the highest binding affinity toward D-fructose and very low sensitivity toward glucose. The reported monoboronic acid based SAB fluorescent sensor showed the highest sensitivity towards glucose with the capacity of detecting saccharides of concentration down to nanomolar level. It was also demonstrated that the fluorescence from PBA/Cys/Au can be easily recovered after each measurement event and therefore also represents a new reusable method for immobilizing reagent in fabricating chemosensors

  10. Molecular polarization potential maps of the nucleic acid bases

    International Nuclear Information System (INIS)

    Alkorta, I.; Perez, J.J.

    1996-01-01

    Ab initio calculations at the SCF level were carried out to compute the polarization potential map NM of the nucleic acid bases: cytosine, thymine, uracil, adedine, and guanine. For this purpose, the Dunning's 9s5p basis set contracted to a split-valence, was selected to perform the calculations. The molecular polarization potential (MPP) at each point was evaluated by the difference between the interaction energy of the molecule with a unit point charge and the molecular electrostatic potential (MEP) at that point. MEPS and MPPS for the different molecules were computed with a density of 5 points/Angstrom 2 on the van der Waals surface of each molecule, defined using the van der Waals radii. Due to the symmetry of the molecules, only half the points were computed. The total number of points calculated was 558 for cytosine, 621 for thymine, 526 for uracil, 666 for adenine, and 699 for guanine. The results of these calculations are analyzed in terms of their implications on the molecular interactions between pairs of nucleic acid bases. 23 refs., 5 figs., 1 tab

  11. Acid-base catalysis of N-[(morpholine)methylene]daunorubicin.

    Science.gov (United States)

    Krause, Anna; Jelińska, Anna; Cielecka-Piontek, Judyta; Klawitter, Maria; Zalewski, Przemysław; Oszczapowicz, Irena; Wąsowska, Małgorzata

    2012-08-01

    The stability of N-[(morpholine)methylene]-daunorubicin hydrochloride (MMD) was investigated in the pH range 0.44-13.54, at 313, 308, 303 and 298 K. The degradation of MMD as a result of hydrolysis is a pseudo-first-order reaction described by the following equation: ln c = ln c(0) - k(obs)• t. In the solutions of hydrochloric acid, sodium hydroxide, borate, acetate and phosphate buffers, k(obs) = k(pH) because general acid-base catalysis was not observed. Specific acid-base catalysis of MMD comprises the following reactions: hydrolysis of the protonated molecules of MMD catalyzed by hydrogen ions (k(1)) and spontaneous hydrolysis of MMD molecules other than the protonated ones (k(2)) under the influence of water. The total rate of the reaction is equal to the sum of partial reactions: k(pH) = k(1) • a(H)+ • f(1) + k(2) • f(2) where: k(1) is the second-order rate constant (mol(-1) l s(-1)) of the specific hydrogen ion-catalyzed degradation of the protonated molecules of MMD; k(2) is the pseudo-first-order rate constant (s(-1)) of the water-catalyzed degradation of MMD molecules other than the protonated ones, f(1) - f(2) are fractions of the compound. MMD is the most stable at approx. pH 2.5.

  12. Acid-base interactions in microbial adhesion to hexadecane and chloroform

    NARCIS (Netherlands)

    Bos, R; Busscher, HJ; Geertsema-Doornbusch, GI; Van Der Mei, HC; Mittal, KL

    2000-01-01

    Acid-base interactions play an important role in adhesion, including microbial adhesion to surfaces. Qualitatively acid-base interactions in microbial adhesion can be demonstrated by comparing adhesion to hexadecane (a negatively charged interface in aqueous solutions, unable to exert acid-base

  13. How Do Undergraduate Students Conceptualize Acid-Base Chemistry? Measurement of a Concept Progression

    Science.gov (United States)

    Romine, William L.; Todd, Amber N.; Clark, Travis B.

    2016-01-01

    We developed and validated a new instrument, called "Measuring Concept progressions in Acid-Base chemistry" (MCAB) and used it to better understand the progression of undergraduate students' understandings about acid-base chemistry. Items were developed based on an existing learning progression for acid-base chemistry. We used the Rasch…

  14. Impedance Source Power Electronic Converters

    DEFF Research Database (Denmark)

    Liu, Yushan; Abu-Rub, Haitham; Ge, Baoming

    Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable...... and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key...... features: Comprehensive analysis of the impedance source converter/inverter topologies, including typical topologies and derived topologies. Fully explains the design and control techniques of impedance source converters/inverters, including hardware design and control parameter design for corresponding...

  15. Impedance source power electronic converters

    CERN Document Server

    Liu, Yushan; Ge, Baoming; Blaabjerg, Frede; Ellabban, Omar; Loh, Poh Chiang

    2016-01-01

    Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key features: Comprehensive analysis of the impedance source converter/inverter topologies, including typical topologies and derived topologies. Fully explains the design and control techniques of impedance source converters/inverters, including hardware design and control parameter design for corresponding control methods. Presents the latest power conversion solutions that aim to advance the role of pow...

  16. Intracranial developmental venous anomaly: is it asymptomatic?

    Science.gov (United States)

    Puente, A Bolívar; de Asís Bravo Rodríguez, F; Bravo Rey, I; Romero, E Roldán

    2018-03-16

    Intracranial developmental venous anomalies are the most common vascular malformation. In the immense majority of cases, these anomalies are asymptomatic and discovered incidentally, and they are considered benign. Very exceptionally, however, they can cause neurological symptoms. In this article, we present three cases of patients with developmental venous anomalies that presented with different symptoms owing to complications derived from altered venous drainage. These anomalies were located in the left insula, right temporal lobe, and cerebellum. The exceptionality of the cases presented as well as of the images associated, which show the mechanism through which the symptoms developed, lies in the low incidence of symptomatic developmental venous anomalies reported in the literature. Copyright © 2018 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

  17. [Emphysematous gastritis with concomitant portal venous air].

    Science.gov (United States)

    Jeong, Min Yeong; Kim, Jin Il; Kim, Jae Young; Kim, Hyun Ho; Jo, Ik Hyun; Seo, Jae Hyun; Kim, Il Kyu; Cheung, Dae Young

    2015-02-01

    Emphysematous gastritis is a rare form of gastritis caused by infection of the stomach wall by gas forming bacteria. It is a very rare condition that carries a high mortality rate. Portal venous gas shadow represents elevation of intestinal luminal pressure which manifests as emphysematous gastritis or gastric emphysema. Literature reviews show that the mortality rate is especially high when portal venous gas shadow is present on CT scan. Until recently, the treatment of emphysematous gastritis has been immediate surgical intervention. However, there is a recent trend of avoiding surgery because of the frequent occurrence of post-operative complications such as anastomosis leakage. In addition, aggressive surgical treatment has failed to show significant improvement in prognosis. Recently, the authors experienced a case of emphysematous gastritis accompanied by portal venous gas which was treated successfully by conservative treatment without immediate surgical intervention. Herein, we present a case of emphysematous gastritis with concomitant portal venous air along with literature review.

  18. VENOUS THROMBOEMBOLISM PROPHYLAXIS – THE OTHER ...

    African Journals Online (AJOL)

    ABSTRACT. Background: There are no local guidelines for prophylaxis against Venous Thrombo-Embolism (VTE). .... of leg ulceration in the age matched general population. (9.6% to ... number of deaths and its cause amongst these patients.

  19. Imaging of head and neck venous malformations

    International Nuclear Information System (INIS)

    Flis, Christine M.; Connor, Stephen E.

    2005-01-01

    Venous malformations (VMs) are non proliferative lesions that consist of dysplastic venous channels. The aim of imaging is to characterise the lesion and define its anatomic extent. We will describe the plain film, ultrasound (US) (including colour and duplex Doppler), computed tomography (CT), magnetic resonance imaging (MRI), conventional angiographic and direct phlebographic appearances of venous malformations. They will be illustrated at a number of head and neck locations, including orbit, oral cavity, superficial and deep facial space, supraglottic and intramuscular. An understanding of the classification of such vascular anomalies is required to define the correct therapeutic procedure to employ. Image-guided sclerotherapy alone or in combination with surgery is now the first line treatment option in many cases of head and neck venous malformations, so the radiologist is now an integral part of the multidisciplinary management team. (orig.)

  20. [Venous thromboembolic disease: presentation of a case].

    Science.gov (United States)

    Mirpuri-Mirpuri, P G; Álvarez-Cordovés, M M; Pérez-Monje, A

    2013-01-01

    Venous thromboembolic disease in its clinical spectrum includes both deep vein thrombosis and pulmonary thromboembolism, which is usually a complication of deep vein thrombosis. It is a relatively common disease with significant morbidity and requires an accurate diagnosis. They are numerous risk factors for venous thromboembolism, and there is evidence that the risk of thromboembolic disease increases proportionally to the number of predisposing risk factors present. The primary care physician should know the risk factors and suspect the presence of venous thromboembolic disease when there is a compatible clnical picture. The treatment for this pathology is anticoagulation. We report a patient with cardiovascular risk factors who was seen with pain in the right leg and shortness of breath and referred to the hospital with suspected venous thromboembolism, atrial fibrillation and pleural effusion. Copyright © 2012 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España. All rights reserved.

  1. Venous trauma in the Lebanon War--2006.

    Science.gov (United States)

    Nitecki, Samy S; Karram, Tony; Hoffman, Aaron; Bass, Arie

    2007-10-01

    Reports on venous trauma are relatively sparse. Severe venous trauma is manifested by hemorrhage, not ischemia. Bleeding may be internal or external and rarely may lead to hypovolemic shock. Repair of major extremity veins has been a subject of controversy and the current teaching is to avoid venous repair in an unstable or multi-trauma patient. The aim of the current paper is to present our recent experience in major venous trauma during the Lebanon conflict, means of diagnosis and treatment in a level I trauma center. All cases of major venous trauma, either isolated or combined with arterial injury, admitted to the emergency room during the 33-day conflict were reviewed. Out of 511 wounded soldiers and civilians who were admitted to our service over this period, 12 (2.3%) sustained a penetrating venous injury either isolated (5) or combined with arterial injury (7). All injuries were secondary to high velocity penetrating missiles or from multiple pellets stored in long-range missiles. All injuries were accompanied by additional insult to soft tissue, bone and viscera. The mean injury severity score was 15. Severe external bleeding was the presenting symptom in three cases of isolated venous injury (jugular, popliteal and femoral). The diagnosis of a major venous injury was made by a CTA scan in five cases, angiography in one and during surgical exploration in six cases. All injured veins were repaired: three by venous interposition grafts, four by end to end anastomosis, three by lateral suture and two by endovascular techniques. None of the injuries was treated by ligation of a major named vein. Immediate postoperative course was uneventful in all patients and the 30-day follow-up (by clinical assessment and duplex scan) has demonstrated a patent repair with no evidence of thrombosis. Without contradicting the wisdom of ligating major veins in the setup of multi-trauma or an unstable patient, our experience indicates that a routine repair of venous trauma can

  2. Fingertip replantation without venous anastomosis.

    Science.gov (United States)

    Chen, Yi-Chieh; Chan, Fuan Chiang; Hsu, Chung-Chen; Lin, Yu-Te; Chen, Chien-Tzung; Lin, Chih-Hung

    2013-03-01

    Replantation of amputated fingertips is a technical challenge, as many salvage procedures fail because no suitable vein in the fingertip is available for anastomosis. In this study, we examined our experience in fingertip replantation in cases without venous anastomosis with our established fingertip replantation treatment protocol. Between August 2002 and August 2010, a retrospective study examined all patients who had undergone fingertip replantation at Chang-Gung Memorial Hospital. All the patients (n = 24) suffered from complete digital amputations at or distal to the interphalangeal joint of the thumb, or distal to distal interphalangeal joint of the fingers. A total of 30 fingertips that were salvaged by microsurgical anastomosis of the digital arteries but not of digital veins were included in this study. On satisfactory arterial anastomosis, a 2-mm incision was made over the fingertip with a number 11 Scalpel blade, and 0.1 to 0.2 mL heparin (5000 IU/mL) was injected subcutaneously around the incision immediately and once per day thereafter to ensure continuous blood drainage from the replanted fingertip. None of the replanted nail plate was removed, and no medical leeches were used. The perfusion of the replanted digits and patient's hemoglobin level were closely monitored. The wound bleeding was maintained until physiologic venous outflow was restored. Of 30 fingertips, 27 (90%) replanted fingertips survived. The average length needed for maintaining external bleeding by chemical leech was 6.8 days (range, 5-10 days). Twelve patients (including a 2-year-old child) received blood transfusions. The average amount of blood transfusion in the 23 adults was 4.0 units (range, 0-16 units) for each patient or 3.29 units (range, 0-14 units) for each digit. A 2-year-old child received 100 mL blood transfusion or 50 mL for each digit. This study showed that a protocol that promotes controlled bleeding from the fingertip is essential to achieve consistent high

  3. Clinicopathologic analysis of Passeriform venous blood reflects transitions in elevation and habitat

    Directory of Open Access Journals (Sweden)

    Heatley JJ

    2013-06-01

    Full Text Available J Jill Heatley,1 Jennifer Cary,2 Karen E Russell,3 Gary Voelker2 1Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, 2Department of Wildlife and Fisheries Sciences and Texas A&M Biodiversity Research and Teaching Collections, Texas A&M University, 3Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, College Station, TX, USA Abstract: Jugular blood samples from 110 Passeriformes collected at several Texas locations were analyzed for multiple clinicopathologic parameters between April 2010 and August 2011. Electrolyte, blood gas, and select erythrocyte parameters were analyzed on site with a point of care analyzer, and gender, age, body condition score, location, and species were recorded. Many analytes exhibited a Gaussian distribution across species and are reported as a single range. Taxon affected electrolyte and red blood cell parameters, but not most blood gas or acid base variables. Migratory status affected select electrolytes but few blood gas variables. Red blood cell parameters were affected the most by variables of age, taxonomic group, and gender, but not migratory life history. We found significant changes in glucose and numerous acid base analytes in birds sampled from habitats with evolutionarily recent ecologic degradation. We advocate the use of these analytes, particularly venous blood gas values, as determined by a point of care analyzer, as reasonable biomarkers for determination of Passeriform population health, but also recommend that red blood cell parameters and electrolyte concentrations be controlled for age, species, and gender in future studies. Further, based on our investigation, venous blood gas values and acid base balance in Passeriformes can assess the health of an ecosystem. Keywords: avian, biochemistry, blood gas, electrolyte, hematology, Passerine

  4. Pathophysiology of spontaneous venous gas embolism

    Science.gov (United States)

    Lambertsen, C. J.; Albertine, K. H.; Pisarello, J. B.; Flores, N. D.

    1991-01-01

    The use of controllable degrees and durations of continuous isobaric counterdiffusion venous gas embolism to investigate effects of venous gas embolism upon blood, cardiovascular, and respiratory gas exchange function, as well as pathological effects upon the lung and its microcirculation is discussed. Use of N2O/He counterdiffusion permitted performance of the pathophysiologic and pulmonary microstructural effects at one ATA without hyperbaric or hypobaric exposures.

  5. Venous hemogasometry of equines finalists in 90 km endurance races

    Directory of Open Access Journals (Sweden)

    Cinthia B.S. Dumont

    2014-06-01

    Full Text Available Front of exercise, the organic systems may suffer water-electrolyte and acid-base imbalances, particularly in the case of blood gases, demonstrating variations from different causes, whether respiratory and/or metabolic. Understanding the physiological adaptations to exercise is essential in the search for the optimum performance. In this way, this study measured the venous blood gases (pO2, pCO2, as well as the oxygen saturation (SatO2 in healthy equines, Arabian horses finalists in 90km endurance races. A total of fourteen Arabian horses were evaluated, nine males and five females, between six and 12 years old, finalists in 90km endurance races. There was a significant reduction in pO2, pCO2 and SatO2 after the exercise, however, the values remained within the normality range, and did not change the athletic performance of the animals, indicating a temporary alteration, assuming thus a character of physiological response to the exercise performed. The equines, finalists in 90 Km endurance races, demonstrated efficient ventilatory process, without any alterations in the athletic performance, being adapted to the type of exercise imposed.

  6. MR findings of cerebral venous sinus thrombosis

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Myung Kwan; Chang, Kee Hyun; Han, Moon Hee; Choi, Choong Gom [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1994-10-15

    To describe MR findings of cerebral venous sinus thrombosis. We reviewed 11 MR images of six patients with cerebral venous sinus thrombosis. The MR images were retrospectively analyzed in terms of location and signal intensity of the thrombi, parenchymal lesions such as hemorrhage and edema, and changes in follow up study obtained in 4 patients. The thrombus in venous sinus was visualized on MRI in all six patients. The most frequently involved sites were superior sagittal sinus(n=4) and left transverse sinus(n=4). Signal intensity of the thrombus was isointense or hyperintense on both T1- and T2-weighted images with loss of normal signal void of the sinus on all sequences in all patients. Parenchymal lesion was patients in five of six cases, manifested as local hemorrhage in three and edema in three cases(one case overlapped). Local edema seen in three patients was completely resolved on follow up study of seven to 29 days intervals. It is concluded that iso- or high signal intensity with loss of signal void in venous sinus is virtually diagnostic of venous sinus thrombosis. If there are local parenchymal lesions such as hemorrhage and/or edema of unknown causes, cerebral venous sinus thrombosis should be included in differential diagnosis.

  7. Evaluating Interest in Acids-Bases: Development of an Acid-Base Interest Scale (ABIS) and Assessment of Pre-Service Science Teachers' Interest

    Science.gov (United States)

    Çiçek, Ö.; Ilhan, N.

    2017-01-01

    Students are more likely to be successful in topics they are interested in than others. This study aims to develop an Acid-Base Interest Scale (ABIS) and subsequently evaluate the interest of pre-service science teachers in acids-bases according to gender, years at the university, type of high school the pre-service science teachers attended, and…

  8. Venous catheterization with ultrasound navigation

    International Nuclear Information System (INIS)

    Kasatkin, A. A.; Nigmatullina, A. R.; Urakov, A. L.

    2015-01-01

    By ultrasound scanning it was determined that respiratory movements made by chest of healthy and sick person are accompanied by respiratory chest rise of internal jugular veins. During the exhalation of an individual diameter of his veins increases and during the breath it decreases down to the complete disappearing if their lumen. Change of the diameter of internal jugular veins in different phases can influence significantly the results of vein puncture and cauterization in patients. The purpose of this research is development of the method increasing the efficiency and safety of cannulation of internal jugular veins by the ultrasound visualization. We suggested the method of catheterization of internal jugular veins by the ultrasound navigation during the execution of which the puncture of venous wall by puncture needle and the following conduction of J-guide is carried out at the moment of patient’s exhalation. This method decreases the risk of complications development during catheterization of internal jugular vein due to exclusion of perforating wound of vein and subjacent tissues and anatomical structures

  9. Venous catheterization with ultrasound navigation

    Energy Technology Data Exchange (ETDEWEB)

    Kasatkin, A. A., E-mail: ant-kasatkin@yandex.ru; Nigmatullina, A. R. [Izhevsk State Medical Academy, Kommunarov street, 281, Izhevsk, Russia, 426034 (Russian Federation); Urakov, A. L., E-mail: ant-kasatkin@yandex.ru [Institute of Mechanics Ural Branch of Russian Academy of Sciences, T.Baramzinoy street 34, Izhevsk, Russia, 426067, Izhevsk (Russian Federation); Izhevsk State Medical Academy, Kommunarov street, 281, Izhevsk, Russia, 426034 (Russian Federation)

    2015-11-17

    By ultrasound scanning it was determined that respiratory movements made by chest of healthy and sick person are accompanied by respiratory chest rise of internal jugular veins. During the exhalation of an individual diameter of his veins increases and during the breath it decreases down to the complete disappearing if their lumen. Change of the diameter of internal jugular veins in different phases can influence significantly the results of vein puncture and cauterization in patients. The purpose of this research is development of the method increasing the efficiency and safety of cannulation of internal jugular veins by the ultrasound visualization. We suggested the method of catheterization of internal jugular veins by the ultrasound navigation during the execution of which the puncture of venous wall by puncture needle and the following conduction of J-guide is carried out at the moment of patient’s exhalation. This method decreases the risk of complications development during catheterization of internal jugular vein due to exclusion of perforating wound of vein and subjacent tissues and anatomical structures.

  10. Boronic acid-based chemical sensors for saccharides.

    Science.gov (United States)

    Zhang, Xiao-Tai; Liu, Guang-Jian; Ning, Zhang-Wei; Xing, Guo-Wen

    2017-11-27

    During the past decades, the interaction between boronic acids-functionalized sensors and saccharides is of great interest in the frontier domain of the interdiscipline concerning both biology and chemistry. Various boronic acid-based sensing systems have been developed to detect saccharides and corresponding derivatives in vitro as well as in vivo, which embrace unimolecular sensors, two-component sensing ensembles, functional assemblies, and boronic acid-loaded nanomaterials or surfaces. New sensing strategies emerge in endlessly with excellent selectivity and sensitivity. In this review, several typical sensing systems were introduced and some promising examples were highlighted to enable the deep insight of saccharides sensing on the basis of boronic acids. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Ultrasonic and densimetric titration applied for acid-base reactions.

    Science.gov (United States)

    Burakowski, Andrzej; Gliński, Jacek

    2014-01-01

    Classical acoustic acid-base titration was monitored using sound speed and density measurements. Plots of these parameters, as well as of the adiabatic compressibility coefficient calculated from them, exhibit changes with the volume of added titrant. Compressibility changes can be explained and quantitatively predicted theoretically in terms of Pasynski theory of non-compressible hydrates combined with that of the additivity of the hydration numbers with the amount and type of ions and molecules present in solution. It also seems that this development could be applied in chemical engineering for monitoring the course of chemical processes, since the applied experimental methods can be carried out almost independently on the medium under test (harmful, aggressive, etc.).

  12. Nucleic Acid-Based Therapy Approaches for Huntington's Disease

    Directory of Open Access Journals (Sweden)

    Tatyana Vagner

    2012-01-01

    Full Text Available Huntington's disease (HD is caused by a dominant mutation that results in an unstable expansion of a CAG repeat in the huntingtin gene leading to a toxic gain of function in huntingtin protein which causes massive neurodegeneration mainly in the striatum and clinical symptoms associated with the disease. Since the mutation has multiple effects in the cell and the precise mechanism of the disease remains to be elucidated, gene therapy approaches have been developed that intervene in different aspects of the condition. These approaches include increasing expression of growth factors, decreasing levels of mutant huntingtin, and restoring cell metabolism and transcriptional balance. The aim of this paper is to outline the nucleic acid-based therapeutic strategies that have been tested to date.

  13. Physicochemical properties of fatty acid based ionic liquids

    International Nuclear Information System (INIS)

    Rocha, Marisa A.A.; Bruinhorst, Adriaan van den; Schröer, Wolffram; Rathke, Bernd; Kroon, Maaike C.

    2016-01-01

    Highlights: • Effects of a branched anion and a mono-unsaturated anion on the physicochemical properties have been explored. • Fatty acid based ionic liquids were synthesized and characterized. • Densities and viscosities at different temperatures have been measured. • The thermal operating window and thermal phase behavior have been evaluated. - Abstract: In this work a series of fatty acid based ionic liquids has been synthesized and characterized. Densities and viscosities at different temperatures have been measured in the temperature range from (293.15 to 363.15) K. The thermal operating window and thermal phase behavior have been evaluated. The effects of a branched anion and a mono-unsaturated anion on the physicochemical properties have been explored. It has been observed that the density (T = 298.15 K) decreases with the following sequence: methyltrioctylammonium 4-ethyloctanoate > methyltrioctylammonium oleate ≈ tetrahexylammonium oleate > tetraoctylammonium oleate, with no detectable dependency of the thermal expansion coefficients on the total number of carbons in the ionic liquid. An almost linear correlation between the molar volumes and the total number of carbons of the alkanes together with the studied ionic liquids was found. The experimental viscosity data were correlated using the Vogel–Fulcher–Tammann (VFT) equation, where a maximum relative deviation of 1.4% was achieved. The ionic liquid with branched alkyl chains on the anion presents the highest viscosity, and methyltrioctylammonium oleate has the highest viscosity compared to the rest of the oleate based ionic liquids. The short and long-term stability were evaluated for all ionic liquids, their long-term decomposition temperatures were found to be significantly lower than their short-term decomposition temperatures. From the long-term thermal analysis was concluded that the highest temperature at which these ionic liquids can be kept is 363 K. In addition, the thermal

  14. Surface acid-base behaviors of Chinese loess.

    Science.gov (United States)

    Chu, Zhaosheng; Liu, Wenxin; Tang, Hongxiao; Qian, Tianwei; Li, Shushen; Li, Zhentang; Wu, Guibin

    2002-08-15

    Acid-base titration was applied to investigate the surface acid-base properties of a Chinese loess sample at different ionic strengths. The acidimetric supernatant was regarded as the system blank of titration to correct the influence of particle dissolution on the estimation of proton consumption. The titration behavior of the system blank could be described by the hydrolysis of Al3+ and Si(OH)4 in aqueous solution as well as the production of hydroxyaluminosilicates. The formation of Al-Si species on homogeneous surface sites by hydrous aluminum and silicic acid, released from solid substrate during the acidic titration, was considered in the model description of the back-titration procedure. A surface reaction model was suggested as follows: >SOHSO(-)+H+, pK(a)(int)=3.48-3.98;>SOH+Al(3+)+H4SiO4SOAl(OSi(OH)3(+)+2H+, pK(SC)=3.48-4.04. Two simple surface complexation models accounted for the interfacial structure, i.e., the constant capacitance model (CCM) and the diffuse layer model (DLM), and gave a satisfactory description of the experimental data. Considering the effect of ionic strength on the electrostatic profile at the solid-aqueous interface, the DLM was appropriate at the low concentrations (0.01 and 0.005 mol/L) of background electrolyte (NaNO3 in this study), while the CCM was preferable in the case of high ionic strength (0.1 mol/L).

  15. Incidence of Postoperative Acid-Base Disturbances in Abdominal Surgery

    Directory of Open Access Journals (Sweden)

    Taghavi Gilani M

    2014-04-01

    Full Text Available Introduction: Respiratory and blood pressure changes as well as fluid administration alter the acid-base balance during the perioperative period which may cause consciousness disturbance and additional hemodynamic disorders. The aim of this study was to identify frequent postoperative acid-base disturbances in order to control postoperative complications. Materials and Methods:This prospective, observational study design was used on patients who underwent abdominal surgery during a six-month period. Gasometry was performed immediately after the patients’ admittion to ICU and six and 12 hours postoperatively. SPSS v13 software was used, and PResults: 213 patients (123 male and 90 female aged 14-85 years (51.7± 22.4 were evaluated. During admission, PH and PaCO2 were (7.29±0.13 and (38.3±11.9, respectively; however, although PH increased gradually (P=0.001, PaCO2 was reduced (P=0.03. Bicarbonate and base excess had opposite effects; bicarbonate initially decreased but increased after 12 hours (P=0.001, whereas base excess initially increased (-6.3±11.6 and then decreased gradually (P=0.003. The arterial oxygen pressure was reduced for 22.5% of the patients throughout the admission period, and this did not significantly change (P=0.57. Conclusion: According to the results, in admission, 65.7% had metabolic acidosis, but metabolic alkalosis was the least. Gradually, metabolic acidosis was modified, but metabolic alkalosis increased. Intraoperative hypotension and fluid infusion may be the main factors of early metabolic acidosis and control of hypotension, or correction of acidosis may increase metabolic alkalosis.

  16. Mechanisms of acid-base regulation in peritoneal dialysis.

    Science.gov (United States)

    Sow, Amadou; Morelle, Johann; Hautem, Nicolas; Bettoni, Carla; Wagner, Carsten A; Devuyst, Olivier

    2017-11-22

    Peritoneal dialysis (PD) contributes to restore acid-base homeostasis in patients with end-stage renal disease. The transport pathways for buffers and carbon dioxide (CO2) across the peritoneal membrane remain poorly understood. Combining well-established PD protocols, whole-body plethysmography and renal function studies in mice, we investigated molecular mechanisms of acid-base regulation in PD, including the potential role of the water channel aquaporin-1 (AQP1). After instillation in peritoneal cavity, the pH of acidic dialysis solutions increased within minutes to rapidly equilibrate with blood pH, whereas the neutral pH of biocompatible solutions remained constant. Predictions from the three-pore model of peritoneal transport suggested that local production of HCO3- accounts at least in part for the changes in intraperitoneal pH observed with acidic solutions. Carbonic anhydrase (CA) isoforms were evidenced in the peritoneal membrane and their inhibition with acetazolamide significantly decreased local production of HCO3- and delayed changes in intraperitoneal pH. On the contrary, genetic deletion of AQP1 had no effect on peritoneal transport of buffers and diffusion of CO2. Besides intraperitoneal modifications, the use of acidic dialysis solutions enhanced acid excretion both at pulmonary and renal levels. These findings suggest that changes in intraperitoneal pH during PD are mediated by bidirectional buffer transport and by CA-mediated production of HCO3- in the membrane. The use of acidic solutions enhances acid excretion through respiratory and renal responses, which should be considered in patients with renal failure. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

  17. Venous, Arterialized-Venous, or Capillary Glucose Reference Measurements for the Accuracy Assessment of a Continuous Glucose Monitoring System.

    Science.gov (United States)

    Kropff, Jort; van Steen, Sigrid C; deGraaff, Peter; Chan, Man W; van Amstel, Rombout B E; DeVries, J Hans

    2017-11-01

    Different reference methods are used for the accuracy assessment of continuous glucose monitoring (CGM) systems. The effect of using venous, arterialized-venous, or capillary reference measurements on CGM accuracy is unclear. We evaluated 21 individuals with type 1 diabetes using a capillary calibrated CGM system. Venous or arterialized-venous reference glucose samples were taken every 15 min at two separate visits and assessed per YSI 2300 STAT Plus. Arterialization was achieved by heated-hand technique. Capillary samples were collected hourly during the venous reference visit. The investigation sequence (venous or arterialized-venous) was randomized. Effectiveness of arterialization was measured by comparing free venous oxygen pressure (PO2) of both visit days. Primary endpoint was the median absolute relative difference (ARD). Median ARD using arterialized-venous reference samples was not different from venous samples (point estimated difference 0.52%, P = 0.181). When comparing the three reference methods, median ARD was also not different over the full glycemic range (venous 9.0% [n = 681], arterialized-venous 8.3% [n = 684], and capillary 8.1% [n = 205], P = 0.216), nor over the separate glucose ranges. Arterialization was successful (PO2 venous 5.4 kPa vs. arterialized-venous 8.9 kPa, P reference measurements did not significantly impact CGM accuracy. Venous reference seems preferable due to its ease of operation.

  18. Proposed electromagnetic wave energy converter

    Science.gov (United States)

    Bailey, R. L.

    1973-01-01

    Device converts wave energy into electric power through array of insulated absorber elements responsive to field of impinging electromagnetic radiation. Device could also serve as solar energy converter that is potentially less expensive and fragile than solar cells, yet substantially more efficient.

  19. Catalytic converters in the fireplace

    International Nuclear Information System (INIS)

    Kouki, J.

    1995-01-01

    In addition to selecting the appropriate means of heating and using dry fuel, the amount of harmful emissions contained by flue gases produced by fireplaces can be reduced by technical means. One such option is to use an oxidising catalytic converter. Tests at TTS Institute's Heating Studies Experimental Station have focused on two such converters (dense and coarse) mounted in light-weight iron heating stoves. The ability of the dense catalytic converter to oxidise carbon monoxide gases proved to be good. The concentration of carbon monoxide in the flue gases was reduced by as much as 90 %. Measurements conducted by VTT (Technical Research Centre of Finland) showed that the conversion of other gases, e.g. of methane, was good. The exhaust resistance caused by the dense converter was so great as to necessitate the mounting of a fluegas evacuation fan in the chimney for the purpose of creating sufficient draught. When relying on natural draught, the dense converter requires a chimney of at least 7 metres and a by-pass connection while the fire is being lit. In addition, the converter will have to be constructed to be less dense and this will mean that it's capability to oxidise non-combusted gases will be reduced. The coarse converter did not impair the draught but it's oxidising property was insufficient. With the tests over, the converter was not observed to have become blocked up by impurities

  20. Multilevel push pull power converter

    DEFF Research Database (Denmark)

    2007-01-01

    A power converter for converting an input voltage (Vin) into an output voltage (Vout), comprising a first supply potential and a second supply potential established by the input voltage, and at least one primary winding having two terminals, a center tap arranged between the two terminals and con...

  1. Femoral venous oxygen saturation is no surrogate for central venous oxygen saturation

    NARCIS (Netherlands)

    van Beest, Paul A.; van der Schors, Alice; Liefers, Henriette; Coenen, Ludo G. J.; Braam, Richard L.; Habib, Najib; Braber, Annemarije; Scheeren, Thomas W. L.; Kuiper, Michael A.; Spronk, Peter E.

    2012-01-01

    Objective:  The purpose of our study was to determine if central venous oxygen saturation and femoral venous oxygen saturation can be used interchangeably during surgery and in critically ill patients. Design:  Prospective observational controlled study. Setting:  Nonacademic university-affiliated

  2. Prevalence of lower extremity venous duplication

    Directory of Open Access Journals (Sweden)

    Simpson William

    2010-01-01

    Full Text Available Purpose: This retrospective study was performed to determine the prevalence of lower extremity venous duplication using duplex ultrasound in the patient population of a large urban medical center. Materials and Methods: The reports of all lower extremity venous ultrasound examinations performed at our institution between January 1, 2002 and December 31, 2002 were reviewed. Ultrasound examinations that were performed for purposes other than the detection of lower extremity deep vein thrombosis were excluded. The prevalence of duplication and its specific location were recorded. In addition, the prevalence of thrombus and its specific location were also recorded. Results: A total of 3118 exams were performed in 2664 patients. Of the 2664 patients, 2311 had only one examination performed during the study period; 353 patients had more than one examination performed. We found that 10.1% of patients (270/2664 had at least one venous segment duplicated and 5.4% of patients (143/2664 had a thrombus in at least one venous segment. There was a statistically significant difference in the prevalence of both duplication and thrombus with a change in venous segment. Only 0.4% of patients (11/2664 had thrombus within a duplicated segment. Of those who had more than one examination performed, 15.3% (54/353 had the same venous segment(s seen on one examination but not another. Conclusion: Lower extremity venous duplication is a frequent anatomic variant that is seen in 10.1% of patients, but it may not be as common as is generally believed. It can result in a false negative result for deep vein thrombosis.

  3. Effect of temperature on the acid-base properties of the alumina surface: microcalorimetry and acid-base titration experiments.

    Science.gov (United States)

    Morel, Jean-Pierre; Marmier, Nicolas; Hurel, Charlotte; Morel-Desrosiers, Nicole

    2006-06-15

    Sorption reactions on natural or synthetic materials that can attenuate the migration of pollutants in the geosphere could be affected by temperature variations. Nevertheless, most of the theoretical models describing sorption reactions are at 25 degrees C. To check these models at different temperatures, experimental data such as the enthalpies of sorption are thus required. Highly sensitive microcalorimeters can now be used to determine the heat effects accompanying the sorption of radionuclides on oxide-water interfaces, but enthalpies of sorption cannot be extracted from microcalorimetric data without a clear knowledge of the thermodynamics of protonation and deprotonation of the oxide surface. However, the values reported in the literature show large discrepancies and one must conclude that, amazingly, this fundamental problem of proton binding is not yet resolved. We have thus undertaken to measure by titration microcalorimetry the heat effects accompanying proton exchange at the alumina-water interface at 25 degrees C. Based on (i) the surface sites speciation provided by a surface complexation model (built from acid-base titrations at 25 degrees C) and (ii) results of the microcalorimetric experiments, calculations have been made to extract the enthalpic variations associated respectively to first and second deprotonation of the alumina surface. Values obtained are deltaH1 = 80+/-10 kJ mol(-1) and deltaH2 = 5+/-3 kJ mol(-1). In a second step, these enthalpy values were used to calculate the alumina surface acidity constants at 50 degrees C via the van't Hoff equation. Then a theoretical titration curve at 50 degrees C was calculated and compared to the experimental alumina surface titration curve. Good agreement between the predicted acid-base titration curve and the experimental one was observed.

  4. Automated method for identification and artery-venous classification of vessel trees in retinal vessel networks.

    Science.gov (United States)

    Joshi, Vinayak S; Reinhardt, Joseph M; Garvin, Mona K; Abramoff, Michael D

    2014-01-01

    The separation of the retinal vessel network into distinct arterial and venous vessel trees is of high interest. We propose an automated method for identification and separation of retinal vessel trees in a retinal color image by converting a vessel segmentation image into a vessel segment map and identifying the individual vessel trees by graph search. Orientation, width, and intensity of each vessel segment are utilized to find the optimal graph of vessel segments. The separated vessel trees are labeled as primary vessel or branches. We utilize the separated vessel trees for arterial-venous (AV) classification, based on the color properties of the vessels in each tree graph. We applied our approach to a dataset of 50 fundus images from 50 subjects. The proposed method resulted in an accuracy of 91.44% correctly classified vessel pixels as either artery or vein. The accuracy of correctly classified major vessel segments was 96.42%.

  5. Racial differences in venous thromboembolism.

    Science.gov (United States)

    Zakai, N A; McClure, L A

    2011-10-01

    The incidence of venous thrombosis (VTE) varies by race, with African-Americans having over 5-fold greater incidence than Asian-ancestry populations, and an intermediate risk for European and Hispanic populations. Known racial differences in genetic polymorphisms associated with thrombosis do not account for this gradient of risk, nor do known racial variations in environmental risk factors. Data on the incidence of and risk factors for VTE outside of Europe and North America and in non-European ancestry populations are sparse. Common genetic polymorphisms in European-Ancestry populations, such as factor V Leiden and prothrombin G20210A, and environmental risk factors, such as obesity, may account for some of the increased risk in European populations, and high factor VIII, high von Willebrand factor and low protein C levels and increased prevalence of obesity may explain some of the increased risk in African-Americans. The low rates in Asian populations may be partially explained by low clinical suspicion in a perceived low-risk population and lack of access to healthcare in other populations. As risk factors for thrombosis, such as surgery and treatment for cancer, are applicable to more people, as obesity increases in prevalence in the developing world, and as surveillance systems for VTE improve, VTE may increase in previously low-risk populations. While differences in VTE by race due to genetic predisposition will probably always be present, understanding the reasons for racial differences in VTE will help providers develop strategies to minimize VTE in all populations. © 2011 International Society on Thrombosis and Haemostasis.

  6. Vanadium oxides supported on hydrotalcite-type precursors: the effect of acid-base properties on the oxidation of isopropanol

    Directory of Open Access Journals (Sweden)

    D. M. Meira

    2006-09-01

    Full Text Available Vanadium oxide supported on hydrotalcite-type precursors was studied in the oxidation of isopropanol. Hydrotalcites with different y = Mg/Al ratios were synthesized by the method of coprecipitation nitrates of Mg and Al cations with K2CO3 as precipitant. The decomposition of these hydrotalcite precursors at 450°C yielded homogeneous MgyAlOx mixed oxides that contain the Al+3 cations totally incorporated into the MgO framework. The materials were characterized by chemical analysis, BET superficial area, X-ray diffraction, temperature-programmed reduction (TPR and the reaction of isopropanol, a probe molecule used to evaluate the acid-base properties. The results of TPR showed that the reducibility of V+5 decreased with the increase in magnesium loading in catalysts. The X-ray diffraction patterns of Al-rich hydrotalcite precursors showed the presence of crystalline phases of brucite and gibbsite. It was shown that chemical composition, texture, acid-base properties of the active sites and also Mg/Al ratio strongly affect the formation of the products in the oxidation of isopropanol. The Al-rich catalysts were much more active than the Mg-rich ones, converting isopropanol mainly to propylene.

  7. Vanadium oxides supported on hydrotalcite-type precursors: the effect of acid base properties on the oxidation of isopropanol

    Energy Technology Data Exchange (ETDEWEB)

    Meira, D.M.; Cortez, G.G. [Faculdade de Engenharia Quimica de Lorena, Lorena, SP (Brazil). Dept. de Engenharia Quimica. Lab. de Catalise II]. E-mail: cortez@dequi.faenquil.br; Monteiro, W.R.; Rodrigues, J.A.J. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Lab. Associado de Combustao e Propulsao]. E-mail: jajr@lcp.inpe.br

    2006-07-15

    Vanadium oxide supported on hydrotalcite-type precursors was studied in the oxidation of isopropanol. Hydrotalcites with different y = Mg/Al ratios were synthesized by the method of coprecipitation nitrates of Mg and Al cations with K{sub 2}CO{sub 3} as precipitant. The decomposition of these hydrotalcite precursors at 450 deg C yielded homogeneous MgyAlOx mixed oxides that contain the Al{sup +3} cations totally incorporated into the MgO framework. The materials were characterized by chemical analysis, BET superficial area, X-ray diffraction, temperature-programmed reduction (TPR) and the reaction of isopropanol, a probe molecule used to evaluate the acid-base properties. The results of TPR showed that the reducibility of V{sup +5} decreased with the increase in magnesium loading in catalysts. The X-ray diffraction patterns of Al-rich hydrotalcite precursors showed the presence of crystalline phases of brucite and gibbsite. It was shown that chemical composition, texture, acid-base properties of the active sites and also Mg/Al ratio strongly affect the formation of the products in the oxidation of isopropanol. The Al-rich catalysts were much more active than the Mg-rich ones, converting isopropanol mainly to propylene. (author)

  8. Venous injury in abusive head trauma

    Energy Technology Data Exchange (ETDEWEB)

    Choudhary, Arabinda K. [Nemours A. I. duPont Hospital for Children, Department of Radiology, Wilmington, DE (United States); Bradford, Ray; Thamburaj, K.; Boal, Danielle K.B. [Hershey Medical Center, Department of Radiology, Hershey, PA (United States); Dias, Mark S. [Hershey Medical Center, Department of Neurosurgery, Hershey, PA (United States)

    2015-11-15

    Abusive head trauma (AHT) is an important cause of serious brain injury in infants and young children who have characteristic clinical and imaging findings that are discordant with the clinical history provided. Recent attention has focused on abnormalities of the cranial venous sinuses and cortical veins, both on MRI and at autopsy. Although many have interpreted these to be secondary to the AHT, some have recently argued that these venous abnormalities represent primary cortical sinus and venous thrombosis that leads secondarily to subdural hemorrhage and secondary brain injury. Direct trauma to the veins and sinuses has been reported at autopsy in AHT, but there has been no systematic study of venous abnormalities in cases of AHT. The purpose of this study was to define the incidence and characteristics of venous and sinus abnormalities in AHT. We included all children <36 months of age who were diagnosed with abusive head trauma between 2001 and 2012 and who had MRI and magnetic resonance (MR) venography as part of their diagnostic workup. We analyzed age, gender and clinical findings. MRI and MR venography were analyzed independently by two neuroradiologists with a focus on abnormalities involving the intracranial veins and venous sinuses. A total of 45 children were included. The median age was 3 months (range 15 days to 31 months) and 28 were boys (62%). Clinical findings included retinal hemorrhage in 71% and extracranial fractures in 55%. CT or MRI demonstrated subdural hemorrhage in 41 (91%); none had subdural effusions. In 31 cases (69%) MR venography demonstrated mass effect on the venous sinuses or cortical draining veins, with either displacement or partial or complete effacement of the venous structures from an adjacent subdural hematoma or brain swelling. We also describe the lollipop sign, which represents direct trauma to the cortical bridging veins and was present in 20/45 (44%) children. Evidence of displacement or compression of cortical veins

  9. Venous injury in abusive head trauma

    International Nuclear Information System (INIS)

    Choudhary, Arabinda K.; Bradford, Ray; Thamburaj, K.; Boal, Danielle K.B.; Dias, Mark S.

    2015-01-01

    Abusive head trauma (AHT) is an important cause of serious brain injury in infants and young children who have characteristic clinical and imaging findings that are discordant with the clinical history provided. Recent attention has focused on abnormalities of the cranial venous sinuses and cortical veins, both on MRI and at autopsy. Although many have interpreted these to be secondary to the AHT, some have recently argued that these venous abnormalities represent primary cortical sinus and venous thrombosis that leads secondarily to subdural hemorrhage and secondary brain injury. Direct trauma to the veins and sinuses has been reported at autopsy in AHT, but there has been no systematic study of venous abnormalities in cases of AHT. The purpose of this study was to define the incidence and characteristics of venous and sinus abnormalities in AHT. We included all children <36 months of age who were diagnosed with abusive head trauma between 2001 and 2012 and who had MRI and magnetic resonance (MR) venography as part of their diagnostic workup. We analyzed age, gender and clinical findings. MRI and MR venography were analyzed independently by two neuroradiologists with a focus on abnormalities involving the intracranial veins and venous sinuses. A total of 45 children were included. The median age was 3 months (range 15 days to 31 months) and 28 were boys (62%). Clinical findings included retinal hemorrhage in 71% and extracranial fractures in 55%. CT or MRI demonstrated subdural hemorrhage in 41 (91%); none had subdural effusions. In 31 cases (69%) MR venography demonstrated mass effect on the venous sinuses or cortical draining veins, with either displacement or partial or complete effacement of the venous structures from an adjacent subdural hematoma or brain swelling. We also describe the lollipop sign, which represents direct trauma to the cortical bridging veins and was present in 20/45 (44%) children. Evidence of displacement or compression of cortical veins

  10. Radiation tolerant power converter controls

    CERN Document Server

    Todd, B; King, Q; Uznanski, S

    2012-01-01

    The Large Hadron Collider (LHC) at the European Organisation for Nuclear Research (CERN) is the world's most powerful particle collider. The LHC has several thousand magnets, both warm and super-conducting, which are supplied with current by power converters. Each converter is controlled by a purpose-built electronic module called a Function Generator Controller (FGC). The FGC allows remote control of the power converter and forms the central part of a closed-loop control system where the power converter voltage is set, based on the converter output current and magnet-circuit characteristics. Some power converters and FGCs are located in areas which are exposed to beam-induced radiation. There are numerous radiation induced effects, some of which lead to a loss of control of the power converter, having a direct impact upon the accelerator's availability. Following the first long shut down (LS1), the LHC will be able to run with higher intensity beams and higher beam energy. This is expected to lead to signifi...

  11. Advanced DC/DC converters

    CERN Document Server

    Luo, Fang Lin

    2003-01-01

    DC/DC conversion techniques have undergone rapid development in recent decades. With the pioneering work of these authors, DC/DC converters have now moved into their sixth generation. This book offers a concise, practical presentation of DC/DC converters, summarizing the spectrum of conversion tecnologies and presentingmany new ideas and more than 100 new topologies. Nowhere else in the literature are DC/DC converters so logically sorted and systematically introduced, and nowhere else can readers find detailed information on prototype topologies that represent a major contribution to modern power engineering. More than 320 figures, 60 tables, and 500 formulae facilitate understand and provide precise data.

  12. Red blood transfusion in preterm infants: changes in glucose, electrolytes and acid base balance

    Directory of Open Access Journals (Sweden)

    Shereen Abdelghaffar

    2012-01-01

    Full Text Available Background: Preterm neonates comprise the most heavily transfused group of patients, and about 85% of extremely low birth weight newborns receive a transfusion by the end of their hospital stay. The aim of this study was to assess the possible metabolic effects of RBC transfusion on preterm infants, especially during the first 2 weeks of life, and its relation to blood volume. Materials and Methods: This study was conducted on 40 preterm neonates with gestational age of less than or equal to 34 weeks. They received RBCs transfusion during first 2 weeks of life. Venous blood samples of infants were collected 2 to 4 hours before and 1 hour after the end of transfusion to evaluate hemoglobin (Hb level, hematocrit, acid-base, electrolytes, and glucose status. Then, infants were classified into two main groups: those who received RBCs volume less than or 20 ml/kg and those who received RBCs volume more than 20 ml/kg. Results: Infants received a mean volume of 20.38 ± 3.2 ml/kg RBCs (range, 10.9 - 26.6 ml/kg at a median age of 9.8 ± 3.6 days. After transfusion, a significant increase of mean Hb (P<0.001, mean Hct (P<0.001, pH (P<0.001, pO 2 (P<0.05, and a significant decrease of the pCO2 (41.46 ± 8.8torr vs 35.4 ± 9.34 torr; P<0.001 were observed. In addition, there was a significant increase of serum K + (P<0.001, and a significant decrease of Ca +2 (P<0.001. A positive correlation was found between the K + intake and the changes of kalemia (r = 0.99; P = 0.00. Furthermore, we observed an inverse correlation between the patients′ calcium intake and the changes of calcemia (r = -0.35; P = 0.02. On comparing the changes in clinical and biochemical variables between two groups after transfusion, we observed a significant increase in mean Hb and Hct associated with a significant decrease in mean serum Ca +2 (P<0.001 in the group receiving the larger blood volume. Conclusion: RBC transfusion was effective in improving anemia, oxygenation, increasing

  13. The acid-base effects of continuous hemofiltration with lactate or bicarbonate buffered replacement fluids.

    Science.gov (United States)

    Tan, H K; Uchino, S; Bellomo, R

    2003-06-01

    To evaluate, quantify and compare the effects of continuous veno-venous hemofiltration (CVVH) with lactate or bicarbonate-buffered replacement fluids on acid-base balance. Randomized double crossover study. Intensive Care Unit of Tertiary Medical Center. Eight patients with severe acute renal failure. Random allocation to either 2 hours of isovolemic lactate-buffered (treatment A) CVVH or 2 hours of bicarbonate-buffered (treatment B) CVVH with cross over and with same procedure repeated the following day (double cross over). Timed collections of arterial blood and ultrafiltrate (UF), measurement of blood and UF gases and lactate concentrations and calculation of buffer-base mass balance. At baseline, both groups of patients had a similar, slight metabolic alkalosis (pH: 7.45 vs. 7.45; BE 3.9 mEq/L for treatment A and 4.0 for treatment B) and a serum bicarbonate of 28.1 mmol/L for treatment A vs. 28.3 mmol/L for treatment B; all NS. This alkalosis was present despite slight hyperlactatemia in both groups (A: 2.4 mmol/L vs. B 2.8 mmol/; NS). Within 60 minutes of treatment, however, treatment A led to a significantly higher lactate concentration (3.9 vs 2.5 mmol/L; p = 0.0011), a significantly lower BE (2.3 vs 4.1 mEq/L; p = 0.0019) and a significantly lower bicarbonate concentration (26.7 vs. 28.3 mmol/L; p = 0.0038) in the presence of an unchanged PaCO2. These differences persisted during the study period. The UF of patients receiving treatment A contained more lactate (10.2 vs 2.9 mmol/L; p buffer-base balance of +20.4 mEq/h compared to -2.6 mEq/h for treatment B; p buffered replacement fluids induces iatrogenic hyperlactatemia. Such hyperlactatemia is associated with an acidifying effect despite a positive buffer-base balance.

  14. Effects of multibuffer supplementation on acid-base balance and 2,3-diphosphoglycerate following repetitive anaerobic exercise.

    Science.gov (United States)

    Kraemer, W J; Gordon, S E; Lynch, J M; Pop, M E; Clark, K L

    1995-12-01

    The purpose of this investigation was to determine the effects of a 3.5-day dietary multibuffer supplement (containing predominantly inorganic phosphate, or Pi, along with bicarbonate and carnosine, i.e., PhosFuel) on repetitive (four trials separated by 2 min rest) Wingate test (WT) performances and whole blood 2,3-diphosphoglycerate (2,3-DPG) concentrations in 10 recreationally trained road cyclists (T) and 10 normally active but untrained (UT) men. A 2-week washout period was utilized between experimental sessions. Venous blood samples were obtained via cannula once before exercise (baseline), immediately post each WT, and 3 min after the final WT (recovery). The data indicate that this supplement does not affect acid-base status with following intense anaerobic exercise and does not improve repetitive WT performance. However, the supplement does enhance post-exercise levels of 2,3-DPG and the 2,3-DPG/Hb ratio in recreationally trained cyclists while improving acute recovery of peak power in these men.

  15. Kinetics of acid base catalyzed transesterification of Jatropha curcas oil.

    Science.gov (United States)

    Jain, Siddharth; Sharma, M P

    2010-10-01

    Out of various non-edible oil resources, Jatropha curcas oil (JCO) is considered as future feedstock for biodiesel production in India. Limited work is reported on the kinetics of transesterification of high free fatty acids containing oil. The present study reports the results of kinetic study of two-step acid base catalyzed transesterification process carried out at an optimum temperature of 65 °C and 50 °C for esterification and transesterification respectively under the optimum methanol to oil ratio of 3:7 (v/v), catalyst concentration 1% (w/w) for H₂SO₄ and NaOH. The yield of methyl ester (ME) has been used to study the effect of different parameters. The results indicate that both esterification and transesterification reaction are of first order with reaction rate constant of 0.0031 min⁻¹ and 0.008 min⁻¹ respectively. The maximum yield of 21.2% of ME during esterification and 90.1% from transesterification of pretreated JCO has been obtained. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. Acid-base transport in pancreas – new challenges

    Directory of Open Access Journals (Sweden)

    Ivana eNovak

    2013-12-01

    Full Text Available Along the gastrointestinal tract a number of epithelia contribute with acid or basic secretions in order to aid digestive processes. The stomach and pancreas are the most extreme examples of acid (H+ and base (HCO3- transporters, respectively. Nevertheless, they share the same challenges of transporting acid and bases across epithelia and effectively regulating their intracellular pH. In this review, we will make use of comparative physiology to enlighten the cellular mechanisms of pancreatic HCO3- and fluid secretion, which is still challenging physiologists. Some of the novel transporters to consider in pancreas are the proton pumps (H+-K+-ATPases, as well as the calcium-activated K+ and Cl- channels, such as KCa3.1 and TMEM16A/ANO1. Local regulators, such as purinergic signalling, fine-tune and coordinate pancreatic secretion. Lastly, we speculate whether dys-regulation of acid-base transport contributes to pancreatic diseases including cystic fibrosis, pancreatitis and cancer.

  17. Modeling the Acid-Base Properties of Montmorillonite Edge Surfaces.

    Science.gov (United States)

    Tournassat, Christophe; Davis, James A; Chiaberge, Christophe; Grangeon, Sylvain; Bourg, Ian C

    2016-12-20

    The surface reactivity of clay minerals remains challenging to characterize because of a duality of adsorption surfaces and mechanisms that does not exist in the case of simple oxide surfaces: edge surfaces of clay minerals have a variable proton surface charge arising from hydroxyl functional groups, whereas basal surfaces have a permanent negative charge arising from isomorphic substitutions. Hence, the relationship between surface charge and surface potential on edge surfaces cannot be described using the Gouy-Chapman relation, because of a spillover of negative electrostatic potential from the basal surface onto the edge surface. While surface complexation models can be modified to account for these features, a predictive fit of experimental data was not possible until recently, because of uncertainty regarding the densities and intrinsic pK a values of edge functional groups. Here, we reexamine this problem in light of new knowledge on intrinsic pK a values obtained over the past decade using ab initio molecular dynamics simulations, and we propose a new formalism to describe edge functional groups. Our simulation results yield reasonable predictions of the best available experimental acid-base titration data.

  18. Acid/base titrations of simulated PWR crevice environments

    International Nuclear Information System (INIS)

    Pang, J.; Macdonald, D.D.; Millett, P.J.

    1993-01-01

    The construction and operation of a titration system that is capable of exploring the acid/base properties of aqueous systems at temperatures solution is measured using YSZ sensors of the type Hg/HgO/ZrO 2 (Y 2 O 3 )/Solution in conjunction with a suitable reference electrode. The use of the system for measuring the pH of the titrated solutions (NaOH/H 2 SO 4 ) is discussed, and we show that the YSZ pH sensor is capable of consistent and precise pH measurements at elevated temperature (275-325 degrees C) and pressures (100-150 bars). However, the accuracy of the measured pH depends critically on the performance of the reference electrode. In the present work, we ensure the viability of the reference electrode. In the present work, we ensure the viability of the reference electrode by periodically calibrating it in situ using the pH sensor and a standard solution of known pH versus temperature characteristics. The titration data obtained in this study are compared with predictions from EPRI's MULTEQ code, and are found to be in satisfactory agreement in the alkaline pH region. Observed discrepancies in the acidic pH region between the two sets of data are attributed to corrosion of the alloys used to fabricate the titration system

  19. Central venous obstruction in the thorax

    International Nuclear Information System (INIS)

    Collin, G.; Jones, R.G.; Willis, A.P.

    2015-01-01

    Central venous stenosis and occlusion can occur secondary to a spectrum of conditions ranging from aggressive malignancy to benign extrinsic anatomical compression in otherwise healthy individuals. Irrespective of aetiology, significant morbidity in the acute setting and long term can occur unless prompt accurate diagnosis and appropriate management is initiated, the radiologist being central to both. The present review will provide radiologists with a thorough illustration and explanation of the range of central venous conditions in the thorax (including deep vein thrombosis, thoracic outlet syndrome, haemodialysis, and malignancy related causes), the salient imaging findings and interventional management using case examples from the authors' practice. - Highlights: • We show a range of causes of central venous disease in the thorax. • We provide information about different imaging and management strategies. • We show several cases with successes and complications of endovascular management

  20. The Essentials of Parathyroid Hormone Venous Sampling

    Energy Technology Data Exchange (ETDEWEB)

    Taslakian, Bedros, E-mail: btaslakian@gmail.com [NYU Langone Medical Center, Department of Radiology, NYU School of Medicine (United States); Trerotola, Scott O., E-mail: streroto@uphs.upenn.edu [Perelman School of Medicine of the University of Pennsylvania, Department of Radiology (United States); Sacks, Barry, E-mail: bsacks@bidmc.harvard.edu [Beth Israel Deaconess Medical Center, Department of Interventional Radiology (United States); Oklu, Rahmi, E-mail: oklu.rahmi@mayo.edu [Mayo Clinic, Department of Interventional Radiology (United States); Deipolyi, Amy, E-mail: deipolya@mskcc.org [Memorial Sloan Kettering Cancer Center, Department of Radiology (United States)

    2017-01-15

    Hyperparathyroidism is an excess of parathyroid hormone in the blood due to over-activity of one or more parathyroid gland. Localization of abnormal glands with noninvasive imaging modalities, such as technetium sestamibi scan and cross-sectional imaging, has a high success rate. Parathyroid venous sampling is performed for patients with persistent or recurrent disease after previous parathyroid surgery, when repeat noninvasive imaging studies are negative or discordant. The success of invasive localization studies and results interpretation is dependent on the interventional radiologist’s understanding of the normal and ectopic anatomic locations of parathyroid glands, as well as their blood supply and venous drainage. Anatomic and technical considerations for selective parathyroid venous sampling are reviewed.

  1. Complications of central venous stenosis due to permanent central venous catheters in children on hemodialysis.

    Science.gov (United States)

    Rinat, Choni; Ben-Shalom, Efrat; Becker-Cohen, Rachel; Feinstein, Sofia; Frishberg, Yaacov

    2014-11-01

    Central venous catheters are frequently used as access for hemodialysis (HD) in children. One of the known complications is central venous stenosis. Although this complication is not rare, it is often asymptomatic and therefore unacknowledged. Superior vena cava (SVC) stenosis is obviously suspected in the presence of upper body edema, but several other signs and symptoms are often unrecognized as being part of this syndrome. We describe four patients with various manifestations of central venous stenosis and SVC syndrome. These sometimes life- or organ-threatening conditions include obstructive sleep apnea, unresolving stridor, increased intracranial pressure, increased intraocular pressure, right-sided pleural effusion, protein-losing enteropathy and lymphadenopathy. The temporal relationship of these complications associated with the use of central venous catheters and documentation of venous stenosis, together with their resolution after alleviation of high venous pressure, points to a causal role. We suggest pathophysiological mechanisms for the formation of each of these complications. In patients with occlusion of the SVC, various unexpected clinical entities can be caused by high central venous pressure. As often the etiology is not obvious, a high index of suspicion is needed as in some cases prompt alleviation of the high pressure is mandatory.

  2. Time-to-digital converters

    CERN Document Server

    Henzler, Stephan

    2010-01-01

    This text covers the fundamentals of time-to-digital converters on analog and digital conversion principles. It includes a theoretical investigation into quantization, linearity, noise and variability, and it details a range of advanced TDC architectures.

  3. [Superficial venous thrombosis. A state of art].

    Science.gov (United States)

    Sándor, Tamás

    2017-01-01

    For a long time superficial thrombophlebitis has been thought to be a rather benign condition. Recently, when duplex ultrasound technique is used for the diagnosis more and more often, the disease is proved to be more dangerous than anticipated. Thrombosis propagates to the deep veins in 6-44% and pulmonary embolism was observed on the patients in 1,5-33%. We can calculate venous thromboembolic complications on every fourth patient. Diagnosis is clinical, but duplex ultrasound examination is mandatory, for estimation of the thrombus extent, for exclusion of the deep venous thrombosis and for follow up. Both legs should be checked with ultrasound, because simultaneous deep venous thrombosis can develop on the contralateral limb. Two different forms can be distinguished: superficial venous thrombosis with, or without varicose veins. In cases of spontaneous, non varicous form, especially when the process is migrating or recurrent, a careful clinical examination is necessery for exclusion of malignant diseases and thrombophilia. The treatment options are summarised on the basis of recent international consensus statements. The American and German guidelines are similar. Compression and mobilisation are cornerstones of the therapy. For a short segment thrombosis non steroidal antiinflammatory drugs are effective. For longer segments low molecular-weight heparins are preferred. Information on the effect of the novel oral anticoagulants for the therapy is lacking but they may appear to be effective in the future for this indication. When thrombus is close to the sapheno-femoral or sapheno-popliteal junction crossectomy (high ligation), or low molecular-weight heparin in therapeutic doses are indicated. The term superficial thrombophlebitis should be discouraged, because inflammation and infection is not the primary pathology. It should be called correctly superficial venous thrombosis in order to avoid the unnecessary administration of antibiotics and the misconception

  4. Transformerless dc-Isolated Converter

    Science.gov (United States)

    Rippel, Wally E.

    1987-01-01

    Efficient voltage converter employs capacitive instead of transformer coupling to provide dc isolation. Offers buck/boost operation, minimal filtering, and low parts count, with possible application in photovoltaic power inverters, power supplies and battery charges. In photovoltaic inverter circuit with transformerless converter, Q2, Q3, Q4, and Q5 form line-commutated inverter. Switching losses and stresses nil because switching performed when current is zero.

  5. Picosecond image-converter diagnostics

    International Nuclear Information System (INIS)

    Schelev, M.Ya.

    1975-01-01

    A brief review is presented of the improvements in picosecond image-converter diagnostics carried out since the previous Congress in 1972. The account is given under the following headings: picosecond image converter cameras for visible and x-ray radiation diagnostics; Nd:glass and ruby mode-locked laser measurements; x-ray plasma emission diagnostics; computer treatment of pictures produced by picosecond cameras. (U.K.)

  6. Management of Peripheral and Truncal Venous Injuries

    Directory of Open Access Journals (Sweden)

    Triantafillos G. Giannakopoulos

    2017-08-01

    Full Text Available Civilian injuries are increasing according to the World Health Organization, and this is attributed mainly to road traffic accidents and urban interpersonal violence. Vascular injuries are common in these scenarios and are associated with high morbidity and mortality rates. Associated peripheral venous trauma is less likely to lead to death and controversy remains whether ligation or repair should be the primary approach. Conversely, non-compressible truncal venous insult can be lethal due to exsanguination, thus a high index of suspicion is crucial. Operative management is demanding with fair results but recent endovascular adjuncts demonstrate promising results and seem to be the way forward for these serious conditions.

  7. Assessment of Venous Thrombosis in Animal Models.

    Science.gov (United States)

    Grover, Steven P; Evans, Colin E; Patel, Ashish S; Modarai, Bijan; Saha, Prakash; Smith, Alberto

    2016-02-01

    Deep vein thrombosis and common complications, including pulmonary embolism and post-thrombotic syndrome, represent a major source of morbidity and mortality worldwide. Experimental models of venous thrombosis have provided considerable insight into the cellular and molecular mechanisms that regulate thrombus formation and subsequent resolution. Here, we critically appraise the ex vivo and in vivo techniques used to assess venous thrombosis in these models. Particular attention is paid to imaging modalities, including magnetic resonance imaging, micro-computed tomography, and high-frequency ultrasound that facilitate longitudinal assessment of thrombus size and composition. © 2015 American Heart Association, Inc.

  8. Admission Hyperglycemia and Clinical Outcome in Cerebral Venous Thrombosis

    NARCIS (Netherlands)

    Zuurbier, Susanna M.; Hiltunen, Sini; Tatlisumak, Turgut; Peters, Guusje M.; Silvis, Suzanne M.; Haapaniemi, Elena; Kruyt, Nyika D.; Putaala, Jukka; Coutinho, Jonathan M.

    2016-01-01

    Background and Purpose-Admission hyperglycemia is associated with poor clinical outcome in ischemic and hemorrhagic stroke. Admission hyperglycemia has not been investigated in patients with cerebral venous thrombosis. Methods-Consecutive adult patients with cerebral venous thrombosis were included

  9. Human cerebral venous outflow pathway depends on posture and central venous pressure

    DEFF Research Database (Denmark)

    Gisolf, J; van Lieshout, J J; van Heusden, K

    2004-01-01

    Internal jugular veins are the major cerebral venous outflow pathway in supine humans. In upright humans the positioning of these veins above heart level causes them to collapse. An alternative cerebral outflow pathway is the vertebral venous plexus. We set out to determine the effect of posture...... and during a Valsalva manoeuvre in both body positions, correlate highly with model simulation of the jugular cross-sectional area (R(2) = 0.97). The results suggest that the cerebral venous flow distribution depends on posture and CVP: in supine humans the internal jugular veins are the primary pathway...

  10. Pregnancy-related venous thromboembolism and risk of occult cancer

    DEFF Research Database (Denmark)

    Hansen, Anette Tarp; Veres, Katalin; Horváth-Puhó, Erzsébet

    2017-01-01

    The cancer risk during the first year after a pregnancy-related venous thromboembolism episode is higher than expected. An aggressive search for cancer in women with pregnancy-related venous thromboembolism is probably not warranted, due to low absolute risk.......The cancer risk during the first year after a pregnancy-related venous thromboembolism episode is higher than expected. An aggressive search for cancer in women with pregnancy-related venous thromboembolism is probably not warranted, due to low absolute risk....

  11. Acid-base thermochemistry of gaseous aliphatic α-aminoacids.

    Science.gov (United States)

    Bouchoux, Guy; Huang, Sihua; Inda, Bhawani Singh

    2011-01-14

    Acid-base thermochemistry of isolated aliphatic amino acids (denoted AAA): glycine, alanine, valine, leucine, isoleucine and proline has been examined theoretically by quantum chemical computations at the G3MP2B3 level. Conformational analysis on neutral, protonated and deprotonated species has been used to identify the lowest energy conformers and to estimate the population of conformers expected to be present at thermal equilibrium at 298 K. Comparison of the G3MP2B3 theoretical proton affinities, PA, and ΔH(acid) with experimental results is shown to be correct if experimental thermochemistry is re-evaluated and adapted to the most recent acidity-basicity scales. From this point of view, a set of evaluated proton affinities of 887, 902, 915, 916, 919 and 941 kJ mol(-1), and a set of evaluated ΔH(acid) of 1433, 1430, 1423, 1423, 1422 and 1426 kJ mol(-1), is proposed for glycine, alanine, valine, leucine, isoleucine and proline, respectively. Correlations with structural parameters (Taft's σ(α) polarizability parameter and molecular size) suggest that polarizability of the side chain is the major origin of the increase in PA and decrease in ΔH(acid) along the homologous series glycine, alanine, valine and leucine/isoleucine. Heats of formation of gaseous species AAA, AAAH(+) and [AAA-H](-) were computed at the G3MP2B3 level. The present study provides previously unavailable Δ(f)H°(298) for the ionized species AAAH(+) and [AAA-H](-). Comparison with Benson's estimate, and correlation with molecular size, show that several experimental Δ(f)H°(298) values of neutral or gaseous AAA might be erroneous.

  12. Pathophysiological aspect of metabolic acid-base disorders

    Directory of Open Access Journals (Sweden)

    Nešović-Ostojić Jelena

    2016-01-01

    Full Text Available Maintaing the arterial pH values (in normal range of 7,35-7,45 is one of the main principles of homeostasis. Regulatory responses, including chemical buffering (extracellular, intracellular, sceletal, the regulation of pCO2 by the respiratory system, and the regulation of [HCO3-] by the kidneys, act in concert to maintain normal arterial pH value. The main extracellular chemical buffer is bicarbonate-carbonic acid buffer system. The kidneys contribute to the regulation of hydrogen (and bicarbonate in body fluids in two ways. Proximal tubules are important in bicarbonate reabsorption and distal tubules excrete hydrogen ion (as ammonium ion or titratable acid. There are four simple acid-base disorders: metabolic acidosis and metabolic alkalosis; respiratory acidosis and respiratory alkalosis. Metabolic acidosis can occur because of an increase in endogenous acid production (such as lactate and ketoacids, loss of bicarbonate (as in diarrhea, or accumulation of endogenous acids (as in renal failure. Metabolic acidosis can also be with high and normal (hyperchloremic metabolic acidosis anion gap. Renal tubular acidosis (RTA is a form of hyperchloremic metabolic acidosis which occurs when the renal damage primarily affects tubular function. The main problem in distal RTA is reduced H+ excretion in distal tubule. Type 2 RTA is also called proximal RTA because the main problem is greatly impaired reabsorption of bicarbonate in proximal tubule. Impaired cation exchange in distal tubule is the main problem in RTA type 4. Metabolic alkalosis occurs as a result of net gain of [HCO3-] or loss of nonvolatile acid from extracellular fluids. Metabolic alkalosis can be associated with reduced or increased extracellular volume.

  13. Congenital absence of infrarenal IVC and iliac venous system : Unusual collateral Pathways

    International Nuclear Information System (INIS)

    Lee, Jin Joo; Lee, Byung Hee; Kim, Kie Hwan; Do, Young Soo; Chin, Soo Yil

    1994-01-01

    We present a case with congenital absence of the infrarenal portion of inferior vena cava and iliac venous system, showing unusual venous collaterals including the left ovarian venous collateral via parametrial venous complex, and a mesenteric-periureteric venous connection. The venous collateral pathways were demonstrated by computed tomography and venography

  14. The influence of respiratory acid-base changes on muscle performance and excitability of the sarcolemma during strenuous intermittent hand grip exercise.

    Science.gov (United States)

    Hilbert, M; Shushakov, V; Maassen, N

    2012-02-01

    Acidification has been reported to provide protective effects on force production in vitro. Thus, in this study, we tested if respiratory acid-base changes influence muscle function and excitability in vivo. Nine subjects performed strenuous, intermittent hand grip exercises (10 cycles of 15 s of work/45 s of rest) under respiratory acidosis by CO(2) rebreathing, alkalosis by hyperventilation, or control. The Pco(2), pH, K(+) concentration ([K(+)]), and Na(+) concentration were measured in venous and arterialized blood. Compound action potentials (M-wave) were elicited to examine the excitability of the sarcolemma. The surface electromyogram (EMG) was recorded to estimate the central drive to the muscle. The lowest venous pH during the exercise period was 7.24 ± 0.03 in controls, 7.31 ± 0.05 with alkalosis, and 7.17 ± 0.04 with acidosis (P alkalosis, and, after the second cycle, it was smaller with acidosis than with the control condition (P Respiratory alkalosis stabilized the M-wave area without influencing performance. Thus, we did not find a direct link between performance and alteration of excitability of the sarcolemma due to changes in pH in vivo.

  15. Mechanochemical endovenous ablation and new frontiers in venous intervention

    NARCIS (Netherlands)

    Boersma, D

    2017-01-01

    Venous insufficiency of the lower extremities is a common condition and related to various symptoms, including venous ulcers. The effect of venous insufficiency on patients’ health-related quality of life is substantial and comparable with other chronic diseases such as arthritis, diabetes, and

  16. Erythrocytes and von Willebrand factor in venous thrombosis

    NARCIS (Netherlands)

    Smeets, M.W.J.

    2018-01-01

    Venous thromboembolism represents the third leading vascular disease after myocardial infarction and stroke. Erythrocytes, the most abundant cells in venous thrombi, were thought to be innocent bystanders that become tangled up in the fibrin mesh of venous thrombi. However, this thesis describes

  17. Contribution of MRI in supracardiac total anomalous pulmonary venous drainage

    International Nuclear Information System (INIS)

    Kastler, B.; Germain, P.; Gangi, A.; Klinkert, A.; Dietemann, J.L.; Wackenheim, A.; Livolsi, A.; Willard, D.

    1992-01-01

    A case of supracardiac total anomalous pulmonary venous drainage (TAPVD) in an infant aged 2 1/2 months is presented. Diagnosis was established non invasively by magnetic resonance image (MRI). Not only did MRI precisely depict the anomalous venous pathway but it moreover securely excluded pulmonary venous obstruction. (orig.)

  18. Diagnostics of defeats of venous collectors of brain

    International Nuclear Information System (INIS)

    Timofeeva, T.V.; Polunina, I.S.; Shcherbakova, E.Ya.; Kuldakova, S.V.

    1997-01-01

    Comparative data of transcranial ultrasonic dopplerography (170 patients) and radionuclidous antroscintigraphy (124), received during diagnostics of defects of venous collectors of brain are analyzed. Five variants of defeats of venous collectors (cross, sigmoid, internal of jugular of jugular vein), but also unpaired sine (direct, confluent) are described. Received results permit to reveal interrelation of infringements of venous outflow and increase of intracranial pressure

  19. Metastatic Carcinoma of Unknown Primary Presenting as Jugular Venous Thrombosis

    Directory of Open Access Journals (Sweden)

    Prince Cheriyan Modayil

    2009-01-01

    Full Text Available Jugular venous thrombosis is unusual and is associated with central venous catheterisation, intravenous drug abuse and head and neck sepsis. It is rarely associated with malignancy. We report a case of metastatic carcinoma of unknown primary in a forty year old female which presented with jugular venous thrombosis. The discussion includes investigation and treatment options for this condition.

  20. Two-inductor boost and buck converters

    Science.gov (United States)

    White, J. L.; Muldoon, W. J.

    The derivation, analysis and design of a coupled inductor boost converter is presented. Aspects of the qualitative ac behavior of coupled inductor converters are discussed. Considerations for the design of the magnetics for such converters are addressed.

  1. Investigation of cerebral venous outflow in microgravity.

    Science.gov (United States)

    Taibi, A; Gadda, G; Gambaccini, M; Menegatti, E; Sisini, F; Zamboni, P

    2017-10-31

    The gravitational gradient is the major component to face when considering the physiology of venous return, and there is a growing interest in understanding the mechanisms ensuring the heart filling, in the absence of gravity, for astronauts who perform long-term space missions. The purpose of the Drain Brain project was to monitor the cerebral venous outflow of a crew member during an experiment on the International Space Station (ISS), so as to study the compensatory mechanisms that facilitate this essential physiological action in subjects living in a microgravity environment. Such venous function has been characterized by means of a novel application of strain-gauge plethysmography which uses a capacitive sensor. In this contribution, preliminary results of our investigation have been presented. In particular, comparison of plethysmography data confirmed that long duration spaceflights lead to a redistribution of venous blood volume, and showed interesting differences in the amplitude of cardiac oscillations measured at the level of the neck veins. The success of the experiment has also demonstrated that thanks to its easy portability, non-invasiveness, and non-operator dependence, the proposed device can be considered as a novel tool for use aboard the ISS. Further trials are now under way to complete the investigation on the drainage function of the neck veins in microgravity.

  2. Pediatric central venous access devices: nursing interventions

    Directory of Open Access Journals (Sweden)

    Duffy EA

    2017-05-01

    Full Text Available Elizabeth A Duffy, Kathryn N Nelson Department of Health Behavior and Biological Sciences, The University of Michigan School of Nursing, Ann Arbor, MI, USA Abstract: A central venous catheter (CVC is an indwelling catheter that provides permanent or temporary stable venous access for both acute and chronically ill pediatric patients. These catheters provide stable venous access that can be used for a variety of medical purposes including drawing blood, hemodynamic monitoring, infusion of intravenous medications, infusion of intravenous fluids, chemotherapy, blood products, and parenteral nutrition. Each day, nurses access and care for CVCs in infants, children, and adolescents; the precision of this care can prevent life-threatening complications. The purpose of this review and the case study is to highlight the importance and components of evidence-based nursing practice in pediatric CVC care. A historical perspective of CVC care is provided in conjunction with current national initiatives to improve patient outcomes for children with CVCs. Infection prevention, clinical practice guidelines, quality improvement, and evidence-based care bundles are discussed. Keywords: pediatric nursing, central venous catheters, central line-associated bloodstream infection, care bundles, pediatric case study 

  3. Thermodilution-determined Internal Jugular Venous Flow

    DEFF Research Database (Denmark)

    Rasmussen, Peter; Widmer, Mario; Hilty, Matthias P

    2017-01-01

    PURPOSE: Cerebral blood flow (CBF) increases ~20% during whole body exercise although a Kety-Schmidt-determined CBF is reported to remain stable; a discrepancy that could reflect evaluation of arterial vs. internal jugular venous (IJV) flow and/or that CBF is influenced by posture. Here we test...

  4. Global public awareness of venous thromboembolism

    NARCIS (Netherlands)

    Wendelboe, A. M.; McCumber, M.; Hylek, E. M.; Buller, H.; Weitz, J. I.; Raskob, G.; Angchaisuksiri, P.; Blanco, A. N.; Hunt, B. J.; Kakkar, A.; Konstantinides, S. V.; McLintock, C.; Ozaki, Y.

    2015-01-01

    Data on public awareness about thrombosis in general and venous thromboembolism (VTE) in particular are limited. We aimed to measure the global awareness of thrombosis to address this gap. With Ipsos-Reid, from 22 July to 5 August 2014, we surveyed 800 respondents in their native language from each

  5. Central Venous Occlusion in the Hemodialysis Patient.

    Science.gov (United States)

    Krishna, Vinay Narasimha; Eason, Joseph B; Allon, Michael

    2016-11-01

    Central venous stenosis (CVS) is encountered frequently among hemodialysis patients. Prior ipsilateral central venous catheterization and cardiac rhythm device insertions are common risk factors, but CVS can also occur in the absence of this history. Chronic CVS can cause thrombosis with partial or complete occlusion of the central vein at the site of stenosis. CVS is frequently asymptomatic and identified as an incidental finding during imaging studies. Symptomatic CVS presents most commonly as an upper- or lower-extremity edema ipsilateral to the CVS. Previously unsuspected CVS may become symptomatic after placement of an ipsilateral vascular access. The likelihood of symptomatic CVS may be affected by the central venous catheter (CVC) location; CVC side; duration of CVC dependence; type, location, and blood flow of the ipsilateral access; and extent of collateral veins. Venous angiography is the gold standard for diagnosis. Percutaneous transluminal angioplasty and stent placement can improve the stenosis and alleviate symptoms, but CVS typically recurs frequently, requiring repeated interventions. Refractory symptomatic CVS may require ligation of the ipsilateral vascular access. Because no available treatment option is curative, the goal should be to prevent CVS by minimizing catheters and central vein instrumentation in patients with chronic kidney disease and dialysis patients. Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  6. Travel and venous thrombosis: a systematic review

    NARCIS (Netherlands)

    Kuipers, S.; Schreijer, A. J. M.; Cannegieter, S. C.; Bueller, H. R.; Rosendaal, F. R.; Middeldorp, S.

    2007-01-01

    In the past decade, numerous publications on the association between venous thrombosis (VT) and travel have been published. Relative and absolute risks of VT after travel, and particularly after travel by air, have been studied in case-control and observational follow-up studies, whereas the effect

  7. Venous thromboembolism: Risk profile and management of ...

    African Journals Online (AJOL)

    Objectives. This study aims to describe the venous thromboembolism (VTE) risk profile of women undergoing elective gynaecological surgery in a tertiary hospital and to audit the VTE prophylaxis prescribed. Methods. One hundred and nine women who underwent elective gynaecological surgery at Kalafong Provincial ...

  8. Urethro-venous intravasation during urethrography

    African Journals Online (AJOL)

    J.M. Ratkal

    Abstract. Retrograde urethrography is a procedure used to evaluate urethral strictures. Urethro-venous intravasation, rarely seen during retrograde urethrography, can result in bacteremia, adverse reactions to contrast agents, renal failure and even pulmonary embolism. We report one such case of a male patient who ...

  9. REVIEW ARTICLE Venous thromboembolism associated with ...

    Indian Academy of Sciences (India)

    Navya

    2017-03-24

    Mar 24, 2017 ... It has been long recognized that reduced PS activity is a risk factor for venous .... individual had PS deficiency type I but was unavailable for DNA .... Influence of PROS1 gene mutations affecting protein S amino-acid 275 on ...

  10. Knowledge, attitude and practice of venous thromboembolism ...

    African Journals Online (AJOL)

    USER

    We aimed to assess the knowledge, attitude and practice of prophylaxis in venous thromboembolism among medical doctors in Usmanu Danfodiyo University Teaching Hospital,. Sokoto, North-West Nigeria. Methodology: The knowledge, attitude and practice of VTE prophylaxis among medical doctors was assessed using ...

  11. Venous infraction of developmental venous anomaly: A case report with perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Youn; Kim, Hye Jeong; Hyun, Su Jeong; Kim, Hee Yeong; Kim, Han Myun; Hwang, Ji Young; Hong, Hye Suk; Woo, Ji Young; Yang, Ik [Dept. of Radiology, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul (Korea, Republic of); Kim, Eun Soo [Dept. of Radiology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang (Korea, Republic of)

    2017-06-15

    Developmental venous anomaly (DVA) is a common congenital venous malformation characterized by dilated medullary veins in caput medusa configuration and a draining vein. Despite the high incidence of DVAs, they are benign anatomic variations and rarely cause symptoms. Here, we report computed tomography and magnetic resonance imaging findings with perfusion images of acute infarction from underlying DVA in a 63-year-old female patient who presented with acute onset of neurologic symptoms and recovered without any neurologic deficit.

  12. Modeling of asymmetrical boost converters

    Directory of Open Access Journals (Sweden)

    Eliana Isabel Arango Zuluaga

    2014-01-01

    Full Text Available The asymmetrical interleaved dual boost (AIDB is a fifth-order DC/DC converter designed to interface photovoltaic (PV panels. The AIDB produces small current harmonics to the PV panels, reducing the power losses caused by the converter operation. Moreover, the AIDB provides a large voltage conversion ratio, which is required to step-up the PV voltage to the large dc-link voltage used in grid-connected inverters. To reject irradiance and load disturbances, the AIDB must be operated in a closed-loop and a dynamic model is required. Given that the AIDB converter operates in Discontinuous Conduction Mode (DCM, classical modeling approaches based on Continuous Conduction Mode (CCM are not valid. Moreover, classical DCM modeling techniques are not suitable for the AIDB converter. Therefore, this paper develops a novel mathematical model for the AIDB converter, which is suitable for control-pur-poses. The proposed model is based on the calculation of a diode current that is typically disregarded. Moreover, because the traditional correction to the second duty cycle reported in literature is not effective, a new equation is designed. The model accuracy is contrasted with circuital simulations in time and frequency domains, obtaining satisfactory results. Finally, the usefulness of the model in control applications is illustrated with an application example.

  13. High-Performance Data Converters

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    -resolution internal D/A converters are required. Unit-element mismatch-shaping D/A converters are analyzed, and the concept of mismatch-shaping is generalized to include scaled-element D/A converters. Several types of scaled-element mismatch-shaping D/A converters are proposed. Simulations show that, when implemented...... in a standard CMOS technology, they can be designed to yield 100 dB performance at 10 times oversampling. The proposed scaled-element mismatch-shaping D/A converters are well suited for use as the feedback stage in oversampled delta-sigma quantizers. It is, however, not easy to make full use of their potential......-order difference of the output signal from the loop filter's first integrator stage. This technique avoids the need for accurate matching of analog and digital filters that characterizes the MASH topology, and it preserves the signal-band suppression of quantization errors. Simulations show that quantizers...

  14. CT findings of posterior fossa venous angiomas

    International Nuclear Information System (INIS)

    Satoh, Toru; Kinugasa, Kazushi; Nishimoto, Akira; Nishimoto, Ken.

    1986-01-01

    Three cases of posterior fossa venous angiomas were reported, with some comments on the CT findings. Case 1: A 53-year-old woman was admitted for the further examination of a viral meningitis which had appeared three months before. Neurological examination revealed no abnormality. Vertebral angiography, however, demonstrated numerous fine medullary veins, with an enlarged intraparenchymal draining vein, in the right cerebellum; they drained into the petrosal vein, which was characteristic of venous angioma. On the plain CT, part of the draining vein was identified as a slightly high-density node. A curvilinear draining vein was demonstrated by the enhanced CT. Case 2: A 29-year-old man was admitted complaining of headache, vomiting, and atxia. Neurological examination disclosed truncal ataxia. The enhanced CT demonstrated two distinct nodules on the anterior border of the hematoma in the deep median cerebellum, probably corresponding to the draining veins. On the angiogram, a venous angioma was found in the bilateral cerebellum; it drained into the precentral cerebellar veins and ultimately joined the straight sinus via the precentro-vermo-rectal vein. Case 3: A 4-year-old boy was admitted suffering from headache, vomiting, and ataxia. Neurological examination disclosed a co-ordination disturbance of the left side. The enhanced CT demonstrated a curvilinear structure inside the hematoma. Angiography showed a venous angioma in the left cerebellum which drained into the petrosal vein. Computerized angiotomography delineated the characteristic venous structure on the angiogram as many fine, high-density lines (medullary veins) converging to a large intraparenchymal linear structure (central medullary vein) and then to a superficial cortical vein. In all cases, large intraparenchymal draining veins were identified by the conventional CT. (J.P.N.)

  15. Anticoagulation period in idiopathic venous thromboembolism

    International Nuclear Information System (INIS)

    Farraj, Rami S.

    2004-01-01

    The period of anticoagulation of a first episode of idiopathic venous thromboembolism has been 6 months. It is unclear if such patients would benefit from longer treatment, as there appears to be an increased risk of recurrence after anticoagulation is stopped. In a randomized prospective study of 64 patients admitted to King Hussein Medical city, Amman, Jordan, who developed a first episode of venous thromboembolism, 32 patients were given warfarin for 24-months, while 32 patients stopped anticoagulation after completion of 6-months of therapy. Our goal was to determine the effects of extended anticoagulation on rates of recurrence of symptomatic venous thromboembolism and bleeding. The patients were followed for 12-months after stopping anticoagulation. After 24-months, 7 of the 32 patients (21%) who had standard anticoagulation for 6-months had a recurrent episode of thromboembolism compared to one of the 32 patients who received anticoagulation for 24 months (3%). Extended warfarin therapy for 24-months has resulted in an absolute risk reduction of 0.1% (p<0.05). This translates into 8 patients having to be treated for 24-months to avoid one recurrence without increasing the risk of major bleeding. Two patients in each group (6%) had major nonfatal bleeding, all 4 bleeding episodes occurring within the first 3-months of anticoagulation. After 36-months of follow up, the recurrence rate of extended warfarin therapy was only 3 patients (9%), which is a 43% relative reduction in recurrence of thromboembolism compared to standard therapy for 6-months. Patients with first episodes of idiopathic venous thromboembolism have an increased risk of recurrent venous thromboembolism and should be treated with oral anticoagulants for longer than 6-months, probably 24-months. (author)

  16. Using the Logarithmic Concentration Diagram, Log "C", to Teach Acid-Base Equilibrium

    Science.gov (United States)

    Kovac, Jeffrey

    2012-01-01

    Acid-base equilibrium is one of the most important and most challenging topics in a typical general chemistry course. This article introduces an alternative to the algebraic approach generally used in textbooks, the graphical log "C" method. Log "C" diagrams provide conceptual insight into the behavior of aqueous acid-base systems and allow…

  17. Stewart analysis of apparently normal acid-base state in the critically ill

    NARCIS (Netherlands)

    Moviat, M.; Boogaard, M. van den; Intven, F.; Voort, P. van der; Hoeven, H. van der; Pickkers, P.

    2013-01-01

    PURPOSE: This study aimed to describe Stewart parameters in critically ill patients with an apparently normal acid-base state and to determine the incidence of mixed metabolic acid-base disorders in these patients. MATERIALS AND METHODS: We conducted a prospective, observational multicenter study of

  18. The acid-base resistant zone in three dentin bonding systems.

    Science.gov (United States)

    Inoue, Go; Nikaido, Toru; Foxton, Richard M; Tagami, Junji

    2009-11-01

    An acid-base resistant zone has been found to exist after acid-base challenge adjacent to the hybrid layer using SEM. The aim of this study was to examine the acid-base resistant zone using three different bonding systems. Dentin disks were applied with three different bonding systems, and then a resin composite was light-cured to make dentin disk sandwiches. After acid-base challenge, the polished surfaces were observed using SEM. For both one- and two-step self-etching primer systems, an acid-base resistant zone was clearly observed adjacent to the hybrid layer - but with differing appearances. For the wet bonding system, the presence of an acid-base resistant zone was unclear. This was because the self-etching primer systems etched the dentin surface mildly, such that the remaining mineral phase of dentin and the bonding agent yielded clear acid-base resistant zones. In conclusion, the acid-base resistant zone was clearly observed when self-etching primer systems were used, but not so for the wet bonding system.

  19. A knowledge based advisory system for acid/base titrations in non-aqueous solvents

    NARCIS (Netherlands)

    Bos, M.; van der Linden, W.E.

    1996-01-01

    A computer program was developed that could advice on the choice of solvent and titrant for acid/base titrations in nonaqueous media. It is shown that the feasibility of a titration in a given solvent can be calculated from solvent properties and intrinsic acid/base properties of the sample

  20. Acid-base properties of the surface of the α-Al2O3 suspension

    Science.gov (United States)

    Ryazanov, M. A.; Dudkin, B. N.

    2009-12-01

    The distribution of the acid-base centers on the surface of α-Al2O3 suspension particles was studied by potentiometric titration, and the corresponding p K spectra were constructed. It was inferred that the double electric layer created by the supporting electrolyte substantially affected the screening of the acid-base centers on the particle surface of the suspension.

  1. Canonical Pedagogical Content Knowledge by Cores for Teaching Acid-Base Chemistry at High School

    Science.gov (United States)

    Alvarado, Clara; Cañada, Florentina; Garritz, Andoni; Mellado, Vicente

    2015-01-01

    The topic of acid-base chemistry is one of the oldest in general chemistry courses and it has been almost continuously in academic discussion. The central purpose of documenting the knowledge and beliefs of a group of ten Mexican teachers with experience in teaching acid-base chemistry in high school was to know how they design, prepare and…

  2. Mixed acid-base disorder secondary to topiramate use in traumatic brain injury

    Directory of Open Access Journals (Sweden)

    S Golla

    2016-01-01

    Full Text Available We report a case of a man with traumatic brain injury. He was started on to prophylactic topiramate which led to a mixed acid-base disorder. He had severe metabolic acidosis secondary to renal tubular acidification defect and respiratory alkalosis secondary to hyperventilation. Withdrawal of the offending drug led to the prompt resolution of the acid-base disturbance.

  3. A Comparative Study of French and Turkish Students' Ideas on Acid-Base Reactions

    Science.gov (United States)

    Cokelez, Aytekin

    2010-01-01

    The goal of this comparative study was to determine the knowledge that French and Turkish upper secondary-school students (grades 11 and 12) acquire on the concept of acid-base reactions. Following an examination of the relevant curricula and textbooks in the two countries, 528 students answered six written questions about the acid-base concept.…

  4. Collaborative Strategies for Teaching Common Acid-Base Disorders to Medical Students

    Science.gov (United States)

    Petersen, Marie Warrer; Toksvang, Linea Natalie; Plovsing, Ronni R.; Berg, Ronan M. G.

    2014-01-01

    The ability to recognize and diagnose acid-base disorders is of the utmost importance in the clinical setting. However, it has been the experience of the authors that medical students often have difficulties learning the basic principles of acid-base physiology in the respiratory physiology curriculum, particularly when applying this knowledge to…

  5. High School Students' Understanding of Acid-Base Concepts: An Ongoing Challenge for Teachers

    Science.gov (United States)

    Damanhuri, Muhd Ibrahim Muhamad; Treagust, David F.; Won, Mihye; Chandrasegaran, A. L.

    2016-01-01

    Using a quantitative case study design, the "Acids-Bases Chemistry Achievement Test" ("ABCAT") was developed to evaluate the extent to which students in Malaysian secondary schools achieved the intended curriculum on acid-base concepts. Responses were obtained from 260 Form 5 (Grade 11) students from five schools to initially…

  6. Thai Grade 11 Students' Alternative Conceptions for Acid-Base Chemistry

    Science.gov (United States)

    Artdej, Romklao; Ratanaroutai, Thasaneeya; Coll, Richard Kevin; Thongpanchang, Tienthong

    2010-01-01

    This study involved the development of a two-tier diagnostic instrument to assess Thai high school students' understanding of acid-base chemistry. The acid-base diagnostic test (ABDT) comprising 18 items was administered to 55 Grade 11 students in a science and mathematics programme during the second semester of the 2008 academic year. Analysis of…

  7. Computed tomographic manifestations of abdominal and pelvic venous collaterals

    International Nuclear Information System (INIS)

    Pagani, J.J.; Thomas, J.L.; Bernardino, M.E.

    1982-01-01

    Obstruction of blood flow through the inferior vena cava and portal vein may produce venous collaterals. These include the paravertebral venous system and its communications with the ascending lumbar veins and azygous/hemiazygous system; gonadal, periureteric, and other retroperitoneal veins; abdominal wall veins; hemorrhoidal venous plexus; and the portal venous system. The anatomic location of these vessels is discussed. Computed tomography demonstrates them as round or tubular structures that are isodens when compared with other venous structures following contrast material administration. Techniques of examination and methods of differentiation of these vascular structures from other abnormalities, especially lymphadenopathy, are discussed

  8. Entanglement in a parametric converter

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Su-Yong; Qamar, Shahid; Lee, Hai-Woong; Zubairy, M Suhail [Center for Quantum Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan)], E-mail: shahid_qamar@pieas.edu.pk, E-mail: zubairy@physics.tamu.edu

    2008-07-28

    In this paper, we consider a parametric converter as a source of entangled radiation. We examine recently derived conditions (Hillery and Zubairy 2006 Phys. Rev. Lett. 96 050503, Duan et al 2000 Phys. Rev. Lett. 84 2722) for determining when the two output modes in a parametric converter are entangled. We show that for different initial field states, the two criteria give different conditions that ensure that the output states are entangled. We also present an input-output calculation for the entanglement of the output field.

  9. Peripheral venous malformations and pulmonary hypertension: A case report and literature review

    Directory of Open Access Journals (Sweden)

    Nambakam Tanuja Subramanyam

    2015-01-01

    Full Text Available Extensive pure peripheral venous malformations are rare. We report occurrence of peripheral venous malformations associated with pulmonary hypertension in a middle-aged male, who had nodular, irregular, soft, compressible, painless, non-pulsatile swellings over dependant positions such as forearms, hands, axilla, and genitalia, with overgrowth of hands and fingers enlarging slowly since early childhood. He had right ventricular failure signs. Plain films showed soft-tissue mass with diffuse calcifications (phleboliths. Doppler study showed low flow vascular channels, compressible hypoechoic lesions along with occasional hyperechoeic lesion corresponding with phleboliths. Magnetic resonance imaging (MRI, T1-weighted showed polypoidal mass with heterogenous hypo to intermediate signal with no flow voids. T2-weighted MRI showed high-signal intensity mass. Computed tomography (CT pulmonary angiogram showed pulmonary hypertension, no thrombi or vascular malformation. He was treated with angiotensin-converting enzyme inhibitors, diuretics, amiodarone, antiplatelets, and venous stockings. Specific therapy such as sclerosis and surgical resection could not be done as he was discharged against medical advice.

  10. Normal venous anatomy and physiology of the lower extremity.

    Science.gov (United States)

    Notowitz, L B

    1993-06-01

    Venous disease of the lower extremities is common but is often misunderstood. It seems that the focus is on the exciting world of arterial anatomy and pathology, while the topic of venous anatomy and pathology comes in second place. However, venous diseases such as chronic venous insufficiency, leg ulcers, and varicose veins affect much of the population and may lead to disability and death. Nurses are often required to answer complex questions from the patients and his or her family about the patient's disease. Patients depend on nurses to provide accurate information in terms they can understand. Therefore it is important to have an understanding of the normal venous system of the legs before one can understand the complexities of venous diseases and treatments. This presents an overview of normal venous anatomy and physiology.

  11. AC-DC PFC Converter Using Combination of Flyback Converter and Full-bridge DC-DC Converter

    Directory of Open Access Journals (Sweden)

    Moh. Zaenal Efendi

    2014-06-01

    Full Text Available This paper presents a combination of power factor correction converter using Flyback converter and Full-bridge dc-dc converter in series connection. Flyback converter is operated in discontinuous conduction mode so that it can serve as a power factor correction converter and meanwhile Full-bridge dc-dc converter is used for dc regulator. This converter system is designed to produce a 86 Volt of output voltage and 2 A of output current. Both simulation and experiment results show that the power factor of this converter achieves up to 0.99 and meets harmonic standard of IEC61000-3-2. Keywords: Flyback Converter, Full-bridge DC-DC Converter, Power Factor Correction.

  12. Current-to-frequency converter

    Energy Technology Data Exchange (ETDEWEB)

    Glowacki, S W [Institute of Nuclear Research, Warsaw (Poland)

    1981-07-15

    A current-to-frequency converter covering the range from 3 x 10/sup -10/ A up to 3 x 10/sup -5/ A of the input current is described. The circuit operates with nuclear detectors featuring a high internal resistance.

  13. Materials for thermionic energy converters

    NARCIS (Netherlands)

    Wolff, L.R.; Hermans, J.M.; Adriaansen, J.K.M.; Gubbels, G.H.M.; Vincenzini, P.

    1987-01-01

    This paper deals with the design and construction of a combustion heated Thermionic Energy Converter (TEC). Main components of this TEC are: 1. A ''Hot Shell'' protecting the TEC from the combustion environment 2. A ''Ceramic Seal'' electrically insulating the emitter from the collector 3. A

  14. Smart AD and DA Converters

    NARCIS (Netherlands)

    Roermund, van A.H.M.; Hegt, J.A.; Harpe, P.J.A.; Radulov, G.I.; Zanikopoulos, A.; Doris, K.; Quinn, P.J.

    2005-01-01

    In this paper, a concept is proposed to solve the problems related to the embedding of AD and DA converters in system-on-chips, FPGAs or other VLSI solutions. Problems like embedded testing, yield, reliability and reduced design space become crucial bottlenecks in the integration of high-performance

  15. Charge-pump voltage converter

    Science.gov (United States)

    Brainard, John P [Albuquerque, NM; Christenson, Todd R [Albuquerque, NM

    2009-11-03

    A charge-pump voltage converter for converting a low voltage provided by a low-voltage source to a higher voltage. Charge is inductively generated on a transfer rotor electrode during its transit past an inductor stator electrode and subsequently transferred by the rotating rotor to a collector stator electrode for storage or use. Repetition of the charge transfer process leads to a build-up of voltage on a charge-receiving device. Connection of multiple charge-pump voltage converters in series can generate higher voltages, and connection of multiple charge-pump voltage converters in parallel can generate higher currents. Microelectromechanical (MEMS) embodiments of this invention provide a small and compact high-voltage (several hundred V) voltage source starting with a few-V initial voltage source. The microscale size of many embodiments of this invention make it ideally suited for MEMS- and other micro-applications where integration of the voltage or charge source in a small package is highly desirable.

  16. Comparison of two analyzers to determine selected venous blood analytes of Quaker parrots (Myiopsitta monachus).

    Science.gov (United States)

    Rettenmund, Christy L; Heatley, J Jill; Russell, Karen E

    2014-06-01

    Point of care devices can assess electrolyte, blood gas, biochemical, and hematologic values in a critical care setting. Although these devices are commonly used in humans and companion mammals, few studies have assessed their use in avian species. This study compares electrolyte, hemoglobin (Hgb), hematocrit (Hct), acid-base, and venous blood gas parameters between the i-STAT and IRMA TruPoint blood gas analysis systems for 35 Quaker parrots. Agreement between the two analyzers and the effect of gender, time lag between sample analysis, and cartridge expiration were evaluated. Male birds had increased Hgb and Hct compared with females, independent of analyzer method. In expired i-STAT cartridges, only glucose significantly increased. Packed cell volume determined by centrifugation was higher than Hct, as calculated by either analyzer. The analyzers had good agreement for total carbon dioxide, bicarbonate, pH, and Hgb, fair agreement for potassium (K), ionized calcium (iCa), venous partial pressure of carbon dioxide, and base excess, and poor agreement for sodium (Na), venous partial pressure of oxygen (PO2), and oxygen saturation (SO2). Values for Na, iCa, PO2, and SO2 were significantly higher on the IRMA than the i-STAT, while K was significantly lower on the IRMA when compared with the i-STAT. The time lag between sample analyses on the i-STAT and IRMA did not be correlate to any analyte changes. Despite these differences, both the i-STAT and the IRMA appear to be acceptable clinical tools in avian critical care, although reference ranges for each analyzer should be created.

  17. Evaluation of hepatic venous pulsatility and portal venous velocity with doppler ultrasonography during the puerperium

    Energy Technology Data Exchange (ETDEWEB)

    Pekindil, Goekhan [Department of Radiology, Trakya University School of Medicine, 22030 Edirne (Turkey); Varol, Fuesun G. [Department of Obstetrics and Gynecology, Trakya University School of Medicine, 22030 Edirne (Turkey); Ali Yuece, M. [Department of Obstetrics and Gynecology, Trakya University School of Medicine, 22030 Edirne (Turkey); Yardim, Turgut [Department of Obstetrics and Gynecology, Trakya University School of Medicine, 22030 Edirne (Turkey)

    1999-03-01

    Objective: The aim of this study is to evaluate pregnancy-induced changes of hepatic venous pulsatility and portal venous velocity in the puerperium and to determine if these changes disappeared by the end of the puerperium. Methods and material: Healthy normal volunteers (90) were examined on the 2nd and 7th days of puerperium and between the 6th and 8th weeks postpartum. Doppler waveform patterns were obtained in the middle hepatic vein and main portal vein. The hepatic venous pulsatility was named as normal, damped or flat. Results: On the 2nd day postpartum, the hepatic vein pulsatility was shown as normal in 8 (26%), damped in 11 (37%) and flat in 11 (37%) cases. On the 7th day postpartum, 15 (50%) cases had normal, 9 (30%) cases had dampened, and 6 (20%) cases had still flat pattern. The majority of the cases (60%) displayed normal hepatic venous pulsatility in the 6th and 8th weeks of puerperium, whereas 23% had still dampened and 17% had flat patterns. There was a trend toward normal pulsatility with increasing puerperal age. The mean portal venous velocity was still higher than the non-pregnant levels and did not showed significant alterations during puerperium. Conclusion: This study emphasised that, since pregnancy-induced alterations in hepatic venous pulsatility and portal venous velocity had not completely returned to normal in most cases until the end of the puerperium, these physiological changes should be considered whenever hepatic and portal systems are interpreted with Doppler sonography during the puerperal period.

  18. Evaluation of hepatic venous pulsatility and portal venous velocity with doppler ultrasonography during the puerperium

    International Nuclear Information System (INIS)

    Pekindil, Goekhan; Varol, Fuesun G.; Ali Yuece, M.; Yardim, Turgut

    1999-01-01

    Objective: The aim of this study is to evaluate pregnancy-induced changes of hepatic venous pulsatility and portal venous velocity in the puerperium and to determine if these changes disappeared by the end of the puerperium. Methods and material: Healthy normal volunteers (90) were examined on the 2nd and 7th days of puerperium and between the 6th and 8th weeks postpartum. Doppler waveform patterns were obtained in the middle hepatic vein and main portal vein. The hepatic venous pulsatility was named as normal, damped or flat. Results: On the 2nd day postpartum, the hepatic vein pulsatility was shown as normal in 8 (26%), damped in 11 (37%) and flat in 11 (37%) cases. On the 7th day postpartum, 15 (50%) cases had normal, 9 (30%) cases had dampened, and 6 (20%) cases had still flat pattern. The majority of the cases (60%) displayed normal hepatic venous pulsatility in the 6th and 8th weeks of puerperium, whereas 23% had still dampened and 17% had flat patterns. There was a trend toward normal pulsatility with increasing puerperal age. The mean portal venous velocity was still higher than the non-pregnant levels and did not showed significant alterations during puerperium. Conclusion: This study emphasised that, since pregnancy-induced alterations in hepatic venous pulsatility and portal venous velocity had not completely returned to normal in most cases until the end of the puerperium, these physiological changes should be considered whenever hepatic and portal systems are interpreted with Doppler sonography during the puerperal period

  19. Impedance interactions in bidirectional cascaded converter

    DEFF Research Database (Denmark)

    Tian, Yanjun; Loh, Poh Chiang; Chen, Zhe

    2016-01-01

    A cascaded converter is built by connecting one elementary converter to another. Output impedance of one converter will therefore interact with input impedance of the other converter. This interaction will change when power flow reverses. To compare this difference, an investigation is performed...

  20. Converter Monitoring Unit for Retrofit of Wind Power Converters

    DEFF Research Database (Denmark)

    Rannestad, Bjorn; Maarbjerg, Anders Eggert; Frederiksen, Kristian

    2018-01-01

    A Converter Monitoring Unit (CMU), which will enable condition monitoring of wind turbine converters is presented in this paper. Reducing the cost of corrective maintenance by means of condition monitoring is a way of lowering Operation & Maintenance (O&M) costs for wind turbine systems....... The CMU must be able to detect a broad range of failure modes related to Insulated Gate Bipolar Transistor (IGBT) power modules and associated gate drives. IGBT collector-emitter on-state voltage (vceon) and current (ic) is sampled in the CMU and used for detection of emerging failures. A new method...... for compensation of unwanted inductive voltage drop in the vceon measurement path is presented, enabling retrofitting of CMUs in existing wind turbines. Finally, experimental results obtained on a prototype CMU are presented. Experimentally the vceon dependency to IGBT junction temperature and deterioration...

  1. Structure and functioning of the acid-base system in the Baltic Sea

    Science.gov (United States)

    Kuliński, Karol; Schneider, Bernd; Szymczycha, Beata; Stokowski, Marcin

    2017-12-01

    The marine acid-base system is relatively well understood for oceanic waters. Its structure and functioning is less obvious for the coastal and shelf seas due to a number of regionally specific anomalies. In this review article we collect and integrate existing knowledge of the acid-base system in the Baltic Sea. Hydrographical and biogeochemical characteristics of the Baltic Sea, as manifested in horizontal and vertical salinity gradients, permanent stratification of the water column, eutrophication, high organic-matter concentrations and high anthropogenic pressure, make the acid-base system complex. In this study, we summarize the general knowledge of the marine acid-base system as well as describe the peculiarities identified and reported for the Baltic Sea specifically. In this context we discuss issues such as dissociation constants in brackish water, different chemical alkalinity models including contributions by organic acid-base systems, long-term changes in total alkalinity, anomalies of borate alkalinity, and the acid-base effects of biomass production and mineralization. Finally, we identify research gaps and specify limitations concerning the Baltic Sea acid-base system.

  2. Lower extremity arterial and venous ulcers.

    Science.gov (United States)

    Sieggreen, Mary

    2005-06-01

    The prevalence of peripheral arterial disease in the general population is high, but the awareness of primary care providers of the disease process is low. The disease is not recognized by primary care providers. Early recognition and treatment of venous diseases that progress to postphlebotic syndrome, such as after a deep vein thrombosis, will prevent venous ulcers that add considerable expense to the health care system. Vascular assessment, including routine ABI measurement of patients who are in risk categories for vascular disease will identify those patients so that prevention programs can be put into place early. Major contributions to the understanding and management of leg ulcers and wound healing have been made in the last decade. However, there is still confusion as to the exact mechanism behind ulcer development and the best method to manage, cure,and prevent these ulcers has yet to be found.

  3. Epidural venous stasis in spinal stenosis

    International Nuclear Information System (INIS)

    Kaiser, M.C.; Capesius, P.; Poos, D.; Gratia, G.; Roilgen, A.; Sandt, G.

    1984-01-01

    Computed tomography permits reliable demonstration of the spinal canal and its contents. Measurements of the sagittal diameter of the bony canal do not take into consideration size, shape and state of intraspinal soft tissue structures, i.e. the thecal sac and its own contents, epidural fat and blood circulation pattern. Three particularly illustrative cases were selected in which obvious epidural venous engorgement was visualized in association with spinal stenosis. The authors think that epidural venous stasis occuring in segmental spinal stenosis is a CT sign of clinically significant narrowing of the neural canal. Accurate recognition of the type of lumbar stenosis together with epidural blood flow alterations permits a better understanding of the existing lesions. Thus, a more precise and specific surgical approach is possible. (orig.)

  4. Deep venous thrombophlebitis following aortoiliac reconstructive surgery

    International Nuclear Information System (INIS)

    Reilly, M.K.; McCabe, C.J.; Abbott, W.M.; Brewster, D.C.; Moncure, A.C.; Reidy, N.C.; Darling, R.C.

    1982-01-01

    One hundred patients undergoing elective aortic surgery were scanned prospectively for development of deep venous thrombosis (DVT). The incidence of DVT in this population was 13%. Eleven patients showed only calf vein thrombosis on venography, whereas two had occlusive iliofemoral thrombus. The correlation between venous Doppler ultrasound and venography was 80%. More importantly, Doppler examination correctly identified both patients with occlusive thrombus. Fibrinogen scanning was associated with a false-positive rate of 31%. Only one patient suffered a nonfatal pulmonary embolus. Fibrinogen scanning has an unacceptably high false-positive rate; however, Doppler ultrasound will identify significant occlusive thrombus without a high false-positive rate. The low incidence of pulmonary emboli does not warrant such definitive measures as prophylactic vena caval interruption

  5. Cerebral venous thrombosis associated with sildenafil intake

    International Nuclear Information System (INIS)

    Miranda Hernández, José Luis; Fernández Cué, Leda; Garzón Cutiño, Lisbel; Gómez Viera, Nelson; Pérez Esquivel, Lianet

    2016-01-01

    A 59 year-old male patient with a history of hypertension and regular consumption of sildenafil entered the service because of acute stroke and headache seizure. Physical examination detected left hemiplegia. By skull nuclear gadolinium magnetic resonance, an expansive lesion is observed which caught heterogeneously contrast. Possible diagnosis of high-grade brain glioma was raised. Right frontoparietal craniotomy was performed and a tumor lesion was not visualized. After ruling out the presence of high-grade glioma, the diagnosis of hemorrhagic venous infarction was assessed. CT angiography and clotting was made to rule out prothrombotic states to justify this disease entity. Special hematology studies were within normal values. The case was concluded as a venous sinus thrombosis associated with the use of sildenafil. (author)

  6. Parametric study of laser photovoltaic energy converters

    Science.gov (United States)

    Walker, G. H.; Heinbockel, J. H.

    1987-01-01

    Photovoltaic converters are of interest for converting laser power to electrical power in a space-based laser power system. This paper describes a model for photovoltaic laser converters and the application of this model to a neodymium laser silicon photovoltaic converter system. A parametric study which defines the sensitivity of the photovoltaic parameters is described. An optimized silicon photovoltaic converter has an efficiency greater than 50 percent for 1000 W/sq cm of neodymium laser radiation.

  7. Bidirectional dc-to-dc Power Converter

    Science.gov (United States)

    Griesbach, C. R.

    1986-01-01

    Solid-state, series-resonant converter uses high-voltage thyristors. Converter used either to convert high-voltage, low-current dc power to lowvoltage, high current power or reverse. Taking advantage of newly-available high-voltage thyristors to provide better reliability and efficiency than traditional converters that use vacuum tubes as power switches. New converter essentially maintenance free and provides greatly increased mean time between failures. Attractive in industrial applications whether or not bidirectional capability is required.

  8. The controversy on chronic cerebrospinal venous insufficiency

    Directory of Open Access Journals (Sweden)

    Paolo Zamboni

    2013-08-01

    Full Text Available The objective of this review is to analyze the actual scientific controversy on chronic cerebrospinal venous insufficiency (CCSVI and its association with both neurodegenerative disorders and multiple sclerosis (MS. We revised all published studies on prevalence of CCSVI in MS patients, including ultrasound and catheter venography series. Furthermore, we take into consideration other publications dealing with the pathophysiologic consequences of CCSVI in the brain, as well as ecent data characterizing the pathology of the venous wall in course of CCSVI. Finally, safety and pilot data on effectiveness of endovascular CCSVI treatment were further updated. Studies of prevalence show a big variability in prevalence of CCSVI in MS patients assessed by established ultrasonographic criteria. This could be related to high operator dependency of ultrasound. However, 12 studies, by the means of more objective catheter venography, show a prevalence >90% of CCSVI in MS. Global hypo-hypoperfusion of the brain, and reduced cerebral spinal fluid dynamics in MS was shown to be related to CCSVI. Postmortem studies and histology corroborate the 2009 International Union of Phlebology (UIP Consensus decision to insert CCSVI among venous malformations. Finally, safety of balloon angioplasty of the extracranial veins was certainly demonstrated, while prospective data on the potential effectiveness of endovascular treatment of CCSVI support to increase the level of evidence by proceeding with a randomized control trial (RCT. Taking into account the current epidemiological data, including studies on catheter venography, the autoptic findings, and the relationship between CCSVI and both hypo-perfusion and cerebro-spinal fluid flow, we conclude that CCSVI can be definitively inserted among the medical entities. Research is still inconclusive in elucidating the CCSVI role in the pathogenesis of neurological disorders. The controversy between the vascular and the

  9. Epidemiology of cancer-related venous thromboembolism

    OpenAIRE

    Wun, Ted; White, Richard H.

    2009-01-01

    Recent studies have better defined the epidemiology of venous thromboembolism (VTE) in cancer patients. The incidence is highest in patients who have metastatic disease at the time of presentation and who have fast growing, biologically aggressive cancers associated with a poor prognosis. The incidence is also high in patients with haematological cancers. Other specific risk factors that affect the incidence of VTE include undergoing invasive neurosurgery, the number of underlying chronic co-...

  10. Bilateral Pneumothoraces Following Central Venous Cannulation

    OpenAIRE

    Pazos, F.; Masterson, K.; Inan, C.; Robert, J.; Walder, B.

    2009-01-01

    We report the occurrence of a bilateral pneumothoraces after unilateral central venous catheterization of the right subclavian vein in a 70-year-old patient. The patient had no history of pulmonary or pleural disease and no history of cardiothoracic surgery. Two days earlier, she had a median laparotomy under general and epidural anaesthesia. Prior to the procedure, the patient was hemodynamically stable and her transcutaneous oxygen saturation was 97% in room air. We punctured the right ...

  11. Parenchymal abnormalities associated with developmental venous anomalies

    Energy Technology Data Exchange (ETDEWEB)

    San Millan Ruiz, Diego; Gailloud, Philippe [Johns Hopkins Hospital, Division of Interventional Neuroradiology, Baltimore, MD (United States); Delavelle, Jacqueline [Geneva University Hospital, Neuroradiology Section, Department of Radiology and Medical Informatics, Geneva (Switzerland); Yilmaz, Hasan; Ruefenacht, Daniel A. [Geneva University Hospital, Section of Interventional Neuroradiology, Department of Clinical Neurosciences, Geneva (Switzerland); Piovan, Enrico; Bertramello, Alberto; Pizzini, Francesca [Verona City Hospital, Service of Neuroradiology, Verona (Italy)

    2007-12-15

    To report a retrospective series of 84 cerebral developmental venous anomalies (DVAs), focusing on associated parenchymal abnormalities within the drainage territory of the DVA. DVAs were identified during routine diagnostic radiological work-up based on magnetic resonance imaging (MRI) (60 cases), computed tomography (CT) (62 cases) or both (36 cases). Regional parenchymal modifications within the drainage territory of the DVA, such as cortical or subcortical atrophy, white matter density or signal alterations, dystrophic calcifications, presence of haemorrhage or a cavernous-like vascular malformation (CVM), were noted. A stenosis of the collecting vein of the DVA was also sought for. Brain abnormalities within the drainage territory of a DVA were encountered in 65.4% of the cases. Locoregional brain atrophy occurred in 29.7% of the cases, followed by white matter lesions in 28.3% of MRI investigations and 19.3% of CT investigations, CVMs in 13.3% of MRI investigations and dystrophic calcification in 9.6% of CT investigations. An intracranial haemorrhage possibly related to a DVA occurred in 2.4% cases, and a stenosis on the collecting vein was documented in 13.1% of cases. Parenchymal abnormalities were identified for all DVA sizes. Brain parenchymal abnormalities were associated with DVAs in close to two thirds of the cases evaluated. These abnormalities are thought to occur secondarily, likely during post-natal life, as a result of chronic venous hypertension. Outflow obstruction, progressive thickening of the walls of the DVA and their morphological organization into a venous convergence zone are thought to contribute to the development of venous hypertension in DVA. (orig.)

  12. Congenital pseudoarthrosis associated with venous malformation

    International Nuclear Information System (INIS)

    Al-Hadidy, A.; Haroun, A.; Al-Ryalat, N.; Hamamy, H.; Al-Hadidi, S.

    2007-01-01

    Congenital pseudoarthrosis is a pathologic entity that may be isolated, or may be associated with neurofibromatosis. We report the case of a 3-year-old female with congenital pseudoarthrosis involving the right tibia and fibula. Magnetic resonance imaging (MRI) and complementary magnetic resonance angiogram (MRA) revealed a lobulated mass with vivid enhancement, which led to the diagnosis of venous malformation. This is the first report of congenital pseudoarthrosis caused by the presence of a vascular malformation. (orig.)

  13. Congenital pseudoarthrosis associated with venous malformation

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hadidy, A.; Haroun, A.; Al-Ryalat, N. [Jordan University Hospital, Radiology Department, P.O. Box 340621, Amman (Jordan); Hamamy, H. [Endocrinology and Genetics, National Center for Diabetes, Amman (Jordan); Al-Hadidi, S. [Jordan University Hospital, Departments of Orthopedics, Amman (Jordan)

    2007-06-15

    Congenital pseudoarthrosis is a pathologic entity that may be isolated, or may be associated with neurofibromatosis. We report the case of a 3-year-old female with congenital pseudoarthrosis involving the right tibia and fibula. Magnetic resonance imaging (MRI) and complementary magnetic resonance angiogram (MRA) revealed a lobulated mass with vivid enhancement, which led to the diagnosis of venous malformation. This is the first report of congenital pseudoarthrosis caused by the presence of a vascular malformation. (orig.)

  14. Inflammation and peripheral venous disease. The San Diego Population Study.

    Science.gov (United States)

    Cushman, M; Callas, P W; Allison, M A; Criqui, M H

    2014-09-02

    The inflammatory response to healing in venous thrombosis might cause vein damage and post-thrombotic syndrome. Inflammation may also be involved in venous insufficiency apart from deep-vein thrombosis. We studied the association of inflammation markers with venous insufficiency in a general population sample. We characterised 2,404 men and women in a general population cohort for peripheral venous disease and its severity using physical exam, symptom assessment, and venous ultrasound. Inflammation markers, C-reactive protein (CRP), fibrinogen, interleukin 1-beta (IL-1-beta), IL-8, IL-10, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin, monocyte chemoattractant-1 (MCP-1) and vascular endothelial cell growth factor (VEGF) were compared in 352 case participants with peripheral venous disease and 352 controls with no venous abnormalities frequency matched to cases by age, sex and race. Associations were also evaluated including a subset of 108 cases of severe venous disease, as previously defined. Odds ratios (95% CI), for peripheral venous disease for biomarkers in the top quartile (adjusting for age, race, sex, body mass index and history of venous thrombosis) were 1.8 (1.1-3.0), 1.6 (1.0-2.5) and 1.5 (0.9-2.3) for CRP, fibrinogen and IL-10, respectively. Associations were larger considering cases of severe venous disease, with odds ratios for these three analytes of 2.6 (1.2-5.9), 3.1 (1.3-7.3) and 2.2 (1.1-4.4), and for IL-8: 2.4 (1.1-5.2). There was no association of IL-1-beta, ICAM-1, VCAM-1, E-selectin, MCP-1 or VEGF with overall cases or severe venous disease. In conclusion, a subset of inflammation markers were associated with increased risk of peripheral venous disease, suggesting potential therapeutic targets for treatment.

  15. Current concepts in repair of extremity venous injury.

    Science.gov (United States)

    Williams, Timothy K; Clouse, W Darrin

    2016-04-01

    Extremity venous injury management remains controversial. The purpose of this communication is to offer perspective as well as experiential and technical insight into extremity venous injury repair. Available literature is reviewed and discussed. Historical context is provided. Indication, the decision process for repair, including technical conduct, is delineated. In particular, the authors' experiences in both civilian and wartime injury are used for perspective. Extremity venous injury repair was championed within data from the Vietnam Vascular Registry. However, patterns of extremity venous injury differ between combat and civilian settings. Since Vietnam, civilian descriptive series opine the benefits and potential complications associated with both venous injury repair and ligation. These surround extremity edema, chronic venous insufficiency, thromboembolism, and limb loss. Whereas no clear superiority in either approach has been identified to date, there appears to be no increased risk of pulmonary embolism or chronic venous changes with repair. Newer data from the wars in Iraq and Afghanistan and meta-analysis have reinforced this and also have suggested limb salvage benefit for extremity venous repair in combined arterial and venous injuries in modern settings. The patient's physiologic state and associated injury drive five triage categories suggesting vein injury management. Vein repair thrombosis occurs in a significant proportion, yet many recanalize and possibly have a positive impact on limb venous return. Further, early decompression favors reduced blood loss, acute edema, and inflammation, supporting collateral development. Large soft tissue injury minimizing collateral capacity increases the importance of repair. Constructs of repair are varied with modest differences in patency. Venous shunting is feasible, but specific roles remain nebulous. An aggressive posture toward extremity venous injury repair seems justified today because of the likely

  16. Ethanol sclerotherapy of peripheral venous malformations

    Energy Technology Data Exchange (ETDEWEB)

    Rimon, U. E-mail: rimonu@sheba.health.gov.il; Garniek, A.; Galili, Y.; Golan, G.; Bensaid, P.; Morag, B

    2004-12-01

    Background: venous malformations are congenital lesions that can cause pain, decreased range of movement, compression on adjacent structures, bleeding, consumptive coagulopathy and cosmetic deformity. Sclerotherapy alone or combined with surgical excision is the accepted treatment in symptomatic malformations after failed treatment attempts with tailored compression garments. Objectives: to report our experience with percutaneous sclerotherapy of peripheral venous malformations with ethanol 96%. Patients and methods: 41 sclerotherapy sessions were performed on 21 patients, aged 4-46 years, 15 females and 6 males. Fourteen patients were treated for painful extremity lesions, while five others with face and neck lesions and two with giant chest malformations had treatment for esthetic reasons. All patients had a pre-procedure magnetic resonance imaging (MRI) study. In all patients, 96% ethanol was used as the sclerosant by direct injection using general anesthesia. A minimum of 1-year clinical follow-up was performed. Follow-up imaging studies were performed if clinically indicated. Results: 17 patients showed complete or partial symptomatic improvement after one to nine therapeutic sessions. Four patients with lower extremity lesions continue to suffer from pain and they are considered as a treatment failure. Complications were encountered in five patients, including acute pulmonary hypertension with cardiovascular collapse, pulmonary embolus, skin ulcers (two) and skin blisters. All patients fully recovered. Conclusion: sclerotherapy with 96% ethanol for venous malformations was found to be effective for symptomatic improvement, but serious complications can occur.

  17. Ethanol sclerotherapy of peripheral venous malformations

    International Nuclear Information System (INIS)

    Rimon, U.; Garniek, A.; Galili, Y.; Golan, G.; Bensaid, P.; Morag, B.

    2004-01-01

    Background: venous malformations are congenital lesions that can cause pain, decreased range of movement, compression on adjacent structures, bleeding, consumptive coagulopathy and cosmetic deformity. Sclerotherapy alone or combined with surgical excision is the accepted treatment in symptomatic malformations after failed treatment attempts with tailored compression garments. Objectives: to report our experience with percutaneous sclerotherapy of peripheral venous malformations with ethanol 96%. Patients and methods: 41 sclerotherapy sessions were performed on 21 patients, aged 4-46 years, 15 females and 6 males. Fourteen patients were treated for painful extremity lesions, while five others with face and neck lesions and two with giant chest malformations had treatment for esthetic reasons. All patients had a pre-procedure magnetic resonance imaging (MRI) study. In all patients, 96% ethanol was used as the sclerosant by direct injection using general anesthesia. A minimum of 1-year clinical follow-up was performed. Follow-up imaging studies were performed if clinically indicated. Results: 17 patients showed complete or partial symptomatic improvement after one to nine therapeutic sessions. Four patients with lower extremity lesions continue to suffer from pain and they are considered as a treatment failure. Complications were encountered in five patients, including acute pulmonary hypertension with cardiovascular collapse, pulmonary embolus, skin ulcers (two) and skin blisters. All patients fully recovered. Conclusion: sclerotherapy with 96% ethanol for venous malformations was found to be effective for symptomatic improvement, but serious complications can occur

  18. Endovascular treatment of intracranial venous sinus thrombosis

    International Nuclear Information System (INIS)

    Xu Shubin; Liang Zhihui; Cui Jinguo; Tian Huiqin; Li Liang; Chen Feng

    2009-01-01

    Objective: To evaluate the clinical efficacy and safety of endovascular treatment for intracranial venous sinus thrombosis. Methods: Ten patients with intracranial venous sinus thrombosis, confirmed by CT, MRI, MRV and / or DSA and encountered during the period of Aug. 2005-Aug. 2007, were treated with endovascular management after they failed to respond to anticoagulant therapy. Of ten patients, intravenous thrombolysis and mechanical thrombus maceration were carried out in 6, while intravenous thrombolysis, mechanical thrombus maceration together with intra-arterial thrombolysis were employed in 4. After the treatment, the anticoagulant therapy continued for 6 months. The patients were followed up for 12-29 months (mean 21 months). Results: After the treatment, the clinical symptoms and signs were completely or partially relieved in eight patients, including disappearance of headache (n=6) and relive of headache (n=2). No obvious improvement was found in one patient and linguistic function disturbance was seen in the remaining one. Lumbar puncture showed that the cerebrospinal fluid pressure returned to normal in all patients. Neither recurrence of thrombosis nor new symptom of neuralgic dysfunction was observed. No procedure-related intracranial or systemic hemorrhagic complications occurred both during and after the operation. Conclusion: Endovascular treatment is an effective and safe procedure for the potentially catastrophic intracranial venous thrombosis. (authors)

  19. Developmental venous anomaly in the newborn brain

    International Nuclear Information System (INIS)

    Horsch, S.; Govaert, P.; Cowan, F.M.; Benders, M.J.N.L.; Groenendaal, F.; Vries, L.S. de; Lequin, M.H.; Saliou, G.

    2014-01-01

    Cerebral developmental venous anomaly (DVA) is considered a benign anatomical variant of parenchymal venous drainage; it is the most common vascular malformation seen in the adult brain. Despite its assumed congenital origin, little is known about DVA in the neonatal brain. We report here the first cohort study of 14 neonates with DVA. Fourteen infants (seven preterm) with DVA diagnosed neonatally using cranial ultrasound (cUS) and magnetic resonance imaging (MRI) from three tertiary neonatal units over 14 years are reviewed. DVA was first detected on cUS in 6 and on MRI in 8 of the 14 infants. The cUS appearances of DVA showed a focal fairly uniform area of increased echogenicity, often (86 %) adjacent to the lateral ventricle and located in the frontal lobe (58 %). Blood flow in the dilated collector vein detected by Doppler ultrasound (US) varied between cases (venous flow pattern in ten and arterialized in four). The appearance on conventional MRI was similar to findings in adults. Serial imaging showed a fairly constant appearance to the DVAs in some cases while others varied considerably regarding anatomical extent and flow velocity. This case series underlines that a neonatal diagnosis of DVA is possible with carefully performed cUS and MRI and that DVA tends to be an incidental finding with a diverse spectrum of imaging appearances. Serial imaging suggests that some DVAs undergo dynamic changes during the neonatal period and early infancy; this may contribute to why diagnosis is rare at this age. (orig.)

  20. Developmental venous anomaly in the newborn brain

    Energy Technology Data Exchange (ETDEWEB)

    Horsch, S. [Erasmus MC-Sophia Children' s Hospital, Department of Neonatology, Rotterdam (Netherlands); Helios Klinikum Berlin-Buch, Department of Neonatology, Berlin (Germany); Govaert, P. [Erasmus MC-Sophia Children' s Hospital, Department of Neonatology, Rotterdam (Netherlands); Cowan, F.M. [Hammersmith Hospital, Department of Paediatrics, Imperial College Healthcare NHS Trust, London (United Kingdom); Benders, M.J.N.L.; Groenendaal, F.; Vries, L.S. de [University Medical Centre Utrecht, Wilhelmina Children' s Hospital, Department of Neonatology, Utrecht (Netherlands); Lequin, M.H. [Erasmus MC/Sophia Children' s Hospital, Department of Paediatric Radiology, Rotterdam (Netherlands); Saliou, G. [University Hospital, Department of Neuroradiology, Le Kremlin-Bicetre (France)

    2014-07-15

    Cerebral developmental venous anomaly (DVA) is considered a benign anatomical variant of parenchymal venous drainage; it is the most common vascular malformation seen in the adult brain. Despite its assumed congenital origin, little is known about DVA in the neonatal brain. We report here the first cohort study of 14 neonates with DVA. Fourteen infants (seven preterm) with DVA diagnosed neonatally using cranial ultrasound (cUS) and magnetic resonance imaging (MRI) from three tertiary neonatal units over 14 years are reviewed. DVA was first detected on cUS in 6 and on MRI in 8 of the 14 infants. The cUS appearances of DVA showed a focal fairly uniform area of increased echogenicity, often (86 %) adjacent to the lateral ventricle and located in the frontal lobe (58 %). Blood flow in the dilated collector vein detected by Doppler ultrasound (US) varied between cases (venous flow pattern in ten and arterialized in four). The appearance on conventional MRI was similar to findings in adults. Serial imaging showed a fairly constant appearance to the DVAs in some cases while others varied considerably regarding anatomical extent and flow velocity. This case series underlines that a neonatal diagnosis of DVA is possible with carefully performed cUS and MRI and that DVA tends to be an incidental finding with a diverse spectrum of imaging appearances. Serial imaging suggests that some DVAs undergo dynamic changes during the neonatal period and early infancy; this may contribute to why diagnosis is rare at this age. (orig.)

  1. Venous access: options, approaches and issues

    International Nuclear Information System (INIS)

    Asch, M.R.

    2001-01-01

    Venous access is an essential part of medical practice. It is needed to obtain blood samples to make the diagnosis and to administer fluids or medicines as part of treatment. Although relatively new in the history of medicine, the placement and maintenance of the various venous access devices now occupies a significant portion of many vascular and interventional radiology practices. Thus, it is important to have a thorough understanding of these devices and their uses. The first long-term venous access devices were used in 1973. These were placed via a surgical cut-down on the subclavian vein. In 1982, the first subcutaneous implantable ports were described. These procedures were initially performed by surgeons, but over the last 5-10 years, both the insertion and management of these devices has shifted to interventional radiologists. Peripherally inserted central catheter (PICC) lines have almost completely supplanted the use of standard central lines (Fig. 1). A number of factors have facilitated this - namely, ready and less expensive room access, outpatient procedure and radiologists' accessibility and familiarity with image-guidance procedures and catheters and guide wires. (author)

  2. An Alternative to Synthetic Acid Base Indicator-Tagetes Erecta Linn

    OpenAIRE

    *A. Elumalai; M. C. Eswariah; M. K. Chinna; B. A. Kumar

    2012-01-01

    The present work highlights the use of the methanolic extract of the flowers of Tagetes erecta as an acid-base indicator in acid-base titrations. This natural indicator is easy to extract as well as easily available. Indicators used in titration show well marked changes of colour in certain intervals of pH. Most of these indicators are organic dyes and are of synthetic origin. Today synthetic indicators are the choice of acid-base titrations. But due to environmental pollution, availability a...

  3. Acid-base equilibrium. A thermodynamic study of formation and stability of the Bi-2223 phase

    International Nuclear Information System (INIS)

    Xi, Z.; Zhou, L.

    1993-01-01

    A general acid-base equilibrium theory was proposed to explain the formation and stability of the Bi-2223 phase based on the Lewis acid base theory and principle of metallurgical physical chemistry. The acid-base nature of oxide was defined according to the electrostatic force between cation and oxygen anion. A series of experimental facts were systematically explained based on the theory: substitution of Bi for Ca in the Pb-free 2223 phase, and the effect of substitution of the high-valent cation for Bi 3+ ; oxygen-pressure atmosphere, and the heat-schocking technique on the formation and stability of the 2223 phase. 14 refs., 2 tabs

  4. Acid-Base and Electrolyte Disorders in Patients with and without Chronic Kidney Disease: An Update.

    Science.gov (United States)

    Dhondup, Tsering; Qian, Qi

    2017-12-01

    Kidneys play a pivotal role in the maintenance and regulation of acid-base and electrolyte homeostasis, which is the prerequisite for numerous metabolic processes and organ functions in the human body. Chronic kidney diseases compromise the regulatory functions, resulting in alterations in electrolyte and acid-base balance that can be life-threatening. In this review, we discuss the renal regulations of electrolyte and acid-base balance and several common disorders including metabolic acidosis, alkalosis, dysnatremia, dyskalemia, and dysmagnesemia. Common disorders in chronic kidney disease are also discussed. The most recent and relevant advances on pathophysiology, clinical characteristics, diagnosis, and management of these conditions have been incorporated.

  5. A REVIEW ON ACID BASE STATUS IN DAIRY COWS: IMPLICATIONS OF DIETARY CATION-ANION BALANCE

    Directory of Open Access Journals (Sweden)

    D. Afzaal, M. Nisa, M. A. Khan and M. Sarwar

    2004-10-01

    Full Text Available The acid base status of a dairy cow is maintained within a narrow range. The key mechanisms involving blood, cells and lungs, perform this function. Although other minerals have an impact on acid base metabolism, the minerals used in dietary cation-anion balance (DCAB namely sodium (Na, potassium (K and chloride (Cl have the greatest effect. Hence, acid base status implicates other biological functions of dairy cows. Low DCAB prepartum reduces the incidence of milk fever and increases the productivity by simmering down the severity of hypocalcaemia. High DCAB diets have proved to increase dry mater and water intake and production and to mitigate the effects of heat stress.

  6. Radiated EMI from power converters

    Directory of Open Access Journals (Sweden)

    Arnautovski-Toševa Vesna

    2005-01-01

    Full Text Available With the continuous increase of switching frequency together with the ongoing trend to higher complexity and functionality, power converters as a part of electronic systems have raised more and more electromagnetic energy pollution to the local system environment. In the same time, stringent demands are imposed on the designers of new circuits that electromagnetic interference (EMI has to be suppressed at its source before it is allowed to propagate into other circuits and systems. In this paper, the authors present a full-wave numerical method for calculation and simulation of electromagnetic field radiated by power converter circuitry. The main objective is to analyze the layout geometry in order to obtain competitive PCB layout that will enable suitably attenuated level of the radiated electric field to safe level. By this it would be possible to ensure reliable operation of the sensitive electronic components in the proximity.

  7. Vibration converter with magnetic levitation

    Science.gov (United States)

    Gladilin, A. V.; Pirogov, V. A.; Golyamina, I. P.; Kulaev, U. V.; Kurbatov, P. A.; Kurbatova, E. P.

    2015-05-01

    The paper presents a mathematical model, the results of computational and theoretical research, and the feasibility of creating a vibration converter with full magnetic levitation in the suspension of a high-temperature superconductor (HTSC). The axial and radial stability of the active part of the converter is provided by the interaction of the magnetic field of ring-shaped permanent magnets and a hollow cylinder made of the ceramic HTSC material. The force is created by a system of current-carrying coils whose magnetic field is polarized by permanent magnets and interacts with induced currents in the superconducting cylinder. The case of transition to the superconducting state of HTSC material in the field of the permanent magnets (FC mode) is considered. The data confirm the outlook for the proposed technical solutions.

  8. Human cerebral venous outflow pathway depends on posture and central venous pressure

    DEFF Research Database (Denmark)

    Gisolf, J; van Lieshout, J J; van Heusden, K

    2004-01-01

    and central venous pressure (CVP) on the distribution of cerebral outflow over the internal jugular veins and the vertebral plexus, using a mathematical model. Input to the model was a data set of beat-to-beat cerebral blood flow velocity and CVP measurements in 10 healthy subjects, during baseline rest......Internal jugular veins are the major cerebral venous outflow pathway in supine humans. In upright humans the positioning of these veins above heart level causes them to collapse. An alternative cerebral outflow pathway is the vertebral venous plexus. We set out to determine the effect of posture...... and a Valsalva manoeuvre in the supine and standing position. The model, consisting of 2 jugular veins, each a chain of 10 units containing nonlinear resistances and capacitors, and a vertebral plexus containing a resistance, showed blood flow mainly through the internal jugular veins in the supine position...

  9. Status of advanced bremsstrahlung converters

    International Nuclear Information System (INIS)

    Halbleib, J.A.

    1980-01-01

    This paper is an attempt to review the somewhat ill-defined area of advanced converter research in a more or less chronological fashion. Section 2 reviews the early B/sub z/ work that was motivated by the CASINO project. More recent work makes liberal use of technology from ICF research using REBs is discussed in Sec. 3. Section 4 discusses possible directions for future research, some of which are being actively pursued at Sandia National Laboratories (SNL) and elsewhere

  10. Computerized simulation of converter process

    Energy Technology Data Exchange (ETDEWEB)

    Jalkanen, H; Suomi, M L; Wallgren, M [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Metallurgy

    1997-12-31

    Converter process is essentially an oxidising refining process aiming in addition to (1) the primary refining action, decarburisation of high carbon iron melt, also to (2) maximal elimination of impurity elements, especially silicon, phosphorus and sulphur, (3) melting of substantial amounts of scrap using the extra heat released in oxidation reactions and (4) to exact final steel temperature control, optimal for further treatments. `Quantitative modelling of such a complex non-stationary chemical process as oxygen converting necessitates extensive formulation of chemical and thermal evolution of the process in connection with the technological properties of the reactor and the process control measures. A comprehensive converter simulation program like CONSIM-3. 1 and its preceding versions that is based on the theoretical and practical knowledge on the process can be used for (1) educating specialists and smelter personnel, (2) planning of the blowing programs, (3) developing and testing of process control systems and after some elaboration and restructuring (4) it can be integrated to static or dynamic process control systems. (orig.) SULA 2 Research Programme; 10 refs.

  11. Computerized simulation of converter process

    Energy Technology Data Exchange (ETDEWEB)

    Jalkanen, H.; Suomi, M.L.; Wallgren, M. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Metallurgy

    1996-12-31

    Converter process is essentially an oxidising refining process aiming in addition to (1) the primary refining action, decarburisation of high carbon iron melt, also to (2) maximal elimination of impurity elements, especially silicon, phosphorus and sulphur, (3) melting of substantial amounts of scrap using the extra heat released in oxidation reactions and (4) to exact final steel temperature control, optimal for further treatments. `Quantitative modelling of such a complex non-stationary chemical process as oxygen converting necessitates extensive formulation of chemical and thermal evolution of the process in connection with the technological properties of the reactor and the process control measures. A comprehensive converter simulation program like CONSIM-3. 1 and its preceding versions that is based on the theoretical and practical knowledge on the process can be used for (1) educating specialists and smelter personnel, (2) planning of the blowing programs, (3) developing and testing of process control systems and after some elaboration and restructuring (4) it can be integrated to static or dynamic process control systems. (orig.) SULA 2 Research Programme; 10 refs.

  12. Development of a Compact Matrix Converter

    Directory of Open Access Journals (Sweden)

    J. Bauer

    2009-01-01

    Full Text Available This paper deals with the development of a matrix converter. Matrix converters belong to the category of direct frequency converters. A converter does not contain DC-link and the output voltage is provided by direct switching of voltage from the input phases. This is enabled by 9 bidirectional switches, which are provided by anti-serial connection of 18 IGBT transistors. The absence of a DC-link is great advantage of the matrix converter, but it also increases the requirements on the converter control. For this reason a new prototype of a matrix converter is being developed with sophisticated modern components (FPGA, Power PC equipped in the control part of the converter. The converter will be used for testing new control algorithms and commutation methods. 

  13. Core content for training in venous and lymphatic medicine.

    Science.gov (United States)

    Zimmet, Steven E; Min, Robert J; Comerota, Anthony J; Meissner, Mark H; Carman, Teresa L; Rathbun, Suman W; Jaff, Michael R; Wakefield, Thomas W; Feied, Craig F

    2014-10-01

    The major venous societies in the United States share a common mission to improve the standards of medical practitioners, the educational goals for teaching and training programs in venous disease, and the quality of patient care related to the treatment of venous disorders. With these important goals in mind, a task force made up of experts from the specialties of dermatology, interventional radiology, phlebology, vascular medicine, and vascular surgery was formed to develop a consensus document describing the Core Content for venous and lymphatic medicine and to develop a core educational content outline for training. This outline describes the areas of knowledge considered essential for practice in the field, which encompasses the study, diagnosis, and treatment of patients with acute and chronic venous and lymphatic disorders. The American Venous Forum and the American College of Phlebology have endorsed the Core Content. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  14. Compression therapies for chronic venous leg ulcers: interventions and adherence

    Directory of Open Access Journals (Sweden)

    Latz CA

    2015-01-01

    Full Text Available Christopher A Latz,1 Kellie R Brown,2 Ruth L Bush11Texas A&M Health Science Center College of Medicine, Bryan, TX, USA; 2Medical College of Wisconsin, Milwaukee, WI, USAAbstract: Compression therapy has been the mainstay for the treatment of lower extremity edema, venous insufficiency, and particularly, venous ulcerative disease. Though modern surgical treatments exist, none are completely effective without good compressive options to allow for decreased swelling and better oxygenation of damaged tissues. This review article will describe the pathophysiology and presentation of lower extremity venous ulcerations, as well as current options for compression therapy. The benefits, along with the major pitfall of nonadherence, will also be discussed.Keywords: venous disease, chronic venous insufficiency, venous ulceration

  15. When acid-base titrations are carried out in unusual conditions

    Directory of Open Access Journals (Sweden)

    Domenico De Marco

    2012-12-01

    Full Text Available Uncommon aspects in acid-base titrations are presented, which occur in titrations between both mono- and/or poly-functional acid and bases but are rarely introduced in ordinary analytical chemistry courses.

  16. Efficacy of pretreating oil palm fronds with an acid-base mixture catalyst.

    Science.gov (United States)

    Jung, Young Hoon; Park, Hyun Min; Park, Yong-Cheol; Park, Kyungmoon; Kim, Kyoung Heon

    2017-07-01

    Oil palm fronds are abundant but recalcitrant to chemical pretreatment. Herein, an acid-base mixture was applied as a catalyst to efficiently pretreat oil palm fronds. Optimized conditions for the pretreatment were a 0.1M acidic acid-base mixture and 3min ramping to 190°C and 12min holding. The oil palm fronds pretreated and washed with the acid-base mixture exhibited an enzymatic digestibility of 85% by 15 FPU Accellerase 1000/g glucan after 72h hydrolysis, which was significantly higher than the enzymatic digestibilities obtained by acid or alkali pretreatment alone. This could be attributed to the synergistic actions of the acid and base, producing an 87% glucose recovery with 100% and 40.3% removal of xylan and lignin, respectively, from the solids. Therefore, an acid-base mixture can be a feasible catalyst to deconstruct oil palm fronds for sugar production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Going Beyond, Going Further: The Preparation of Acid-Base Titration Curves.

    Science.gov (United States)

    McClendon, Michael

    1984-01-01

    Background information, list of materials needed, and procedures used are provided for a simple technique for generating mechanically plotted acid-base titration curves. The method is suitable for second-year high school chemistry students. (JN)

  18. [Venous thrombosis associated with central venous catheter use in patients with cancer].

    Science.gov (United States)

    Iglesias Rey, Leticia; Fernández Pérez, Isaura; Barbagelata López, Cristina; Rivera Gallego, Alberto

    2015-01-01

    The use of central venous catheters for various applications (administration of chemotherapy, blood products and others) in patients with cancer is increasingly frequent. The association between thrombosis and catheter use has been fully established but aspects such as its causes, diagnosis, prophylaxis and treatment have not. We describe a case of thrombosis in a patient with cancer treated with chemotherapy who carried a central venous catheter. We also perform a review of the risk factors, the role of the prophylaxis and the treatment. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

  19. Venous Return and Clinical Hemodynamics: How the Body Works during Acute Hemorrhage

    Science.gov (United States)

    Shen, Tao; Baker, Keith

    2015-01-01

    Venous return is a major determinant of cardiac output. Adjustments within the venous system are critical for maintaining venous pressure during loss in circulating volume. This article reviews two factors that are thought to enable the venous system to compensate during acute hemorrhage: 1) changes in venous elastance and 2) mobilization of…

  20. Complexity in Acid?Base Titrations: Multimer Formation Between Phosphoric Acids and Imines

    OpenAIRE

    Malm, Christian; Kim, Heejae; Wagner, Manfred; Hunger, Johannes

    2017-01-01

    Abstract Solutions of Br?nsted acids with bases in aprotic solvents are not only common model systems to study the fundamentals of proton transfer pathways but are also highly relevant to Br?nsted acid catalysis. Despite their importance the light nature of the proton makes characterization of acid?base aggregates challenging. Here, we track such acid?base interactions over a broad range of relative compositions between diphenyl phosphoric acid and the base quinaldine in dichloromethane, by u...

  1. Amino acid-based dithiazines: synthesis and photofragmentation of their benzaldehyde adducts.

    Science.gov (United States)

    Kurchan, Alexei N; Kutateladze, Andrei G

    2002-11-14

    Alpha-amino acids and GABA are functionalized with dithiazine rings via reaction with sodium hydrosulfide in aqueous formaldehyde. The resulting dithiazines are lithiated at -78 degrees C and reacted with benzaldehyde furnishing amino acid-based 2,5-bis-substituted dithiazines. These adducts undergo externally sensitized photofragmentation with quantum efficiency comparable to that of the parent dithiane adducts, thus offering a novel approach to amino acid-based photolabile tethers. [reaction: see text

  2. Respiratory Adaptations in Acid-base Disturbances: Role of Cerebral Fluids,

    Science.gov (United States)

    1979-06-19

    The respiratory and metabolic components of acid-base homeostasis are defined. A quantitative empirical description of the (incomplete) mutual...literature. Respiratory adaptations in steady acid-base disturbances of metabolic origin (hyperventilation with hypocapnia in primary metabolic acidosis, and...hypoventilation with hypercapnia in metabolic alkalosis ) are analyzed as a function of the acidity of the cerebral fluids (cerebrospinal and cerebral interstitial fluid). (Author)

  3. A Clinical Approach to the Diagnosis of Acid-Base Disorders

    OpenAIRE

    Bear, Robert A.

    1986-01-01

    The ability to diagnose and manage acid-base disorders rapidly and effectively is essential to the care of critically ill patients. This article presents an approach to the diagnosis of pure and mixed acid-base disorders, metabolic or respiratory. The approach taken is based on using the law of mass-action equation as it applies to the bicarbonate buffer system (Henderson equation), using sub-classifications for diagnostic purposes of causes of metabolic acidosis and metabolic alkalosis, and ...

  4. An unusual cause of hydrocephalus: aqueductal developmental venous anomaly

    Energy Technology Data Exchange (ETDEWEB)

    Yagmurlu, Banu; Fitoz, Suat; Atasoy, Cetin; Erden, ilhan [Ankara University School of Medicine, Department of Radiology, Ankara (Turkey); Deda, Gulhis; Unal, Ozlem [Ankara University School of Medicine, Division of Pediatric Neurology, Ankara (Turkey)

    2005-06-01

    Vascular malformations are infrequent causes of aqueductal stenoses, developmental venous anomaly (DVA) being the rarest among them. DVAs, also known as venous angiomas, are congenital in origin and characterized by dilatation of vessels in the superficial and deep venous system. Although they are usually clinically silent, they can be complicated by hemorrhage, seizures and neurologic deficits. Herein, we report MR imaging findings of a 7-year-old girl whose hydrocephalus was due to an abnormal vein coursing through the aqueduct. (orig.)

  5. Massive hydrothorax with malpositioned central venous catheter – Ultrasound detection

    Directory of Open Access Journals (Sweden)

    Neha Hasija

    2016-04-01

    Full Text Available Radioimaging is the gold standard for confirmation of the position of central venous catheter as well as its related complications. Use of ultrasound has been proven in guiding central venous cannulations, and it can also be used in detecting related complications. We report a case of a 2 year old child with hydrothorax causing desaturation due to malpositioned central venous catheter diagnosed by ultrasound in the delay for getting a radiograph.

  6. Simulation Results of Double Forward Converter

    Directory of Open Access Journals (Sweden)

    P. Vijaya KUMAR

    2009-12-01

    Full Text Available This work aims to find a better forward converter for DC to DC conversion.Simulation of double forward converter in SMPS system is discussed in this paper. Aforward converter with RCD snubber to synchronous rectifier and/or to current doubleris also discussed. The evolution of the forward converter is first reviewed in a tutorialfashion. Performance parameters are discussed including operating principle, voltageconversion ratio, efficiency, device stress, small-signal dynamics, noise and EMI. Itscircuit operation and its performance characteristics of the forward converter with RCDsnubber and double forward converter are described and the simulation results arepresented.

  7. Venous ulcers of the lower limb: Where do we stand?

    Directory of Open Access Journals (Sweden)

    Chatterjee S Sasanka

    2012-01-01

    Full Text Available Venous ulcers are the most common ulcers of the lower limb. It has a high morbidity and results in economic strain both at a personal and at a state level. Chronic venous hypertension either due to primary or secondary venous disease with perforator paucity, destruction or incompetence resulting in reflux is the underlying pathology, but inflammatory reactions mediated through leucocytes, platelet adhesion, formation of pericapillary fibrin cuff, growth factors and macromolecules trapped in tissue result in tissue hypoxia, cell death and ulceration. Duplex scan with colour flow is the most useful investigation for venous disease supplying information about patency, reflux, effects of proximal and distal compression, Valsalva maneuver and effects of muscle contraction. Most venous disease can be managed conservatively by leg elevation and compression bandaging. Drugs of proven benefit in venous disease are pentoxifylline and aspirin, but they work best in conjunction with compression therapy. Once ulceration is chronic or the patient does not respond to or cannot maintain conservative regime, surgical intervention treating the underlying venous hypertension and cover for the ulcer is necessary. The different modalities like sclerotherapy, ligation and stripping of superficial varicose veins, endoscopic subfascial perforator ligation, endovenous laser or radiofrequency ablation have similar long-term results, although short-term recovery is best with radiofrequency and foam sclerotherapy. For deep venous reflux, surgical modalities include repair of incompetent venous valves or transplant or transposition of a competent vein segment with normal valves to replace a post-thrombotic destroyed portion of the deep vein.

  8. Pregnancy-related venous thromboembolism and risk of occult cancer

    DEFF Research Database (Denmark)

    Tarp Hansen, Anette; Veres, Katalin; Horváth-Puhó, Erzsébet

    2017-01-01

    The cancer risk during the first year after a pregnancy-related venous thromboembolism episode is higher than expected.An aggressive search for cancer in women with pregnancy-related venous thromboembolism is probably not warranted, due to low absolute risk.......The cancer risk during the first year after a pregnancy-related venous thromboembolism episode is higher than expected.An aggressive search for cancer in women with pregnancy-related venous thromboembolism is probably not warranted, due to low absolute risk....

  9. Percutaneous transfemoral repositioning of malpositioned central venous catheters.

    Science.gov (United States)

    Hartnell, G G; Roizental, M

    1995-04-01

    Central venous catheters inserted by blind surgical placement may not advance into a satisfactory position and may require repositioning. Malpositioning via surgical insertion is common in patients in whom central venous catheters have previously been placed, as these patients are more likely to have central venous thrombosis and distortion of central venous anatomy. This is less of a problem when catheter placement is guided by imaging; however, even when insertion is satisfactory, central venous catheters may become displaced spontaneously after insertion (Fig. 1). Repositioning can be effected by direct manipulation using guidewires or tip-deflecting wires [1, 2], by manipulation via a transfemoral venous approach [3-5], and by injection of contrast material or saline [6]. Limitations of the direct approach include (1) the number and type of maneuvers that can be performed to effect repositioning when anatomy is distorted, (2) difficulty in accessing the catheter, and (3) the risk of introducing infection. Moreover, these patients are often immunosuppressed, and there is a risk of introducing infection by exposing and directly manipulating the venous catheter. Vigorous injection of contrast material or saline may be unsuccessful for the same reasons: It seldom exerts sufficient force to reposition large-caliber central venous catheters and may cause vessel damage or rupture if injection is made into a small or thrombosed vessel. We illustrate several alternative methods for catheter repositioning via a transfemoral venous approach.

  10. Quantitative acid-base physiology using the Stewart model. Does it improve our understanding of what is really wrong?

    NARCIS (Netherlands)

    Derksen, R.; Scheffer, G.J.; Hoeven, J.G. van der

    2006-01-01

    Traditional theories of acid-base balance are based on the Henderson-Hasselbalch equation to calculate proton concentration. The recent revival of quantitative acid-base physiology using the Stewart model has increased our understanding of complicated acid-base disorders, but has also led to several

  11. Auxiliary resonant DC tank converter

    Science.gov (United States)

    Peng, Fang Z.

    2000-01-01

    An auxiliary resonant dc tank (ARDCT) converter is provided for achieving soft-switching in a power converter. An ARDCT circuit is coupled directly across a dc bus to the inverter to generate a resonant dc bus voltage, including upper and lower resonant capacitors connected in series as a resonant leg, first and second dc tank capacitors connected in series as a tank leg, and an auxiliary resonant circuit comprising a series combination of a resonant inductor and a pair of auxiliary switching devices. The ARDCT circuit further includes first clamping means for holding the resonant dc bus voltage to the dc tank voltage of the tank leg, and second clamping means for clamping the resonant dc bus voltage to zero during a resonant period. The ARDCT circuit resonantly brings the dc bus voltage to zero in order to provide a zero-voltage switching opportunity for the inverter, then quickly rebounds the dc bus voltage back to the dc tank voltage after the inverter changes state. The auxiliary switching devices are turned on and off under zero-current conditions. The ARDCT circuit only absorbs ripples of the inverter dc bus current, thus having less current stress. In addition, since the ARDCT circuit is coupled in parallel with the dc power supply and the inverter for merely assisting soft-switching of the inverter without participating in real dc power transmission and power conversion, malfunction and failure of the tank circuit will not affect the functional operation of the inverter; thus a highly reliable converter system is expected.

  12. Electromechanical converters for electric vehicles

    Science.gov (United States)

    Ambros, T.; Burduniuc, M.; Deaconu, S. I.; Rujanschi, N.

    2018-01-01

    The paper presents the analysis of various constructive schemes of synchronous electromechanical converters with permanent magnets fixed on the rotor and asynchronous with the short-circuit rotor. Various electrical stator winding schemes have also been compared, demonstrating the efficiency of copper utilization in toroidal windings. The electromagnetic calculus of the axial machine has particularities compared to the cylindrical machine, in the paper is presented the method of correlating the geometry of the cylindrical and axial machines. In this case the method and recommendations used in the design of such machines may be used.

  13. Power electronics converters and regulators

    CERN Document Server

    Dokić, Branko L

    2015-01-01

    This book is the result of the extensive experience the authors gained through their year-long occupation at the Faculty of Electrical Engineering at the University of Banja Luka. Starting at the fundamental basics of electrical engineering, the book guides the reader into this field and covers all the relevant types of converters and regulators. Understanding is enhanced by the given examples, exercises and solutions. Thus this book can be used as a textbook for students, for self-study or as a reference book for professionals.

  14. Predictors of Venous Thromboembolic Events Associated with Central Venous Port Insertion in Cancer Patients

    Directory of Open Access Journals (Sweden)

    Christine Hohl Moinat

    2014-01-01

    Full Text Available Insertion of central venous port (CVP catheter in the cancer population is associated with increased incidence of venous thromboembolic events (VTE. However, trials have shown limited benefit of antithrombotic treatment to prevent catheter-related venous thrombosis. This prospective observational cohort study was designed to assess the incidence of VTE closely related to CVP implantation in patients with cancer and undergoing chemotherapy, and to identify a high risk subgroup of patients. Between February 2006 and December 2011, 1097 consecutive cancer patients with first CVP implantation were included. Catheter-related VTE were defined as deep venous thrombosis in the arm, with or without pulmonary embolism (PE, or isolated PE. The incidence of CVP-associated VTE was 5.9% (IC95 4.4–7.3% at 3 months, and 11.3% (IC95 9.4–13.2% at 12 months. The incidence of any VTE was 7.6% (IC95 6.0–9.3% at 3 months, and 15.3% (IC95 13.1–17.6% at 12 months. High Khorana risk score and lung cancer were significant predictors of 3 month VTE. In conclusion, this large cohort study of patients with first CVP catheter implantation confirms the high incidence of VTE associated with the CVP implantation and allow identifying high risk patients who may benefit from thromboprophylaxis.

  15. Diagnosis and endovascular treatment of multiple cerebral venous and venous sinuses thrombosis

    International Nuclear Information System (INIS)

    Li Baomin; Zhang Ji; Yin Ling; Huang Xusheng; Jiang Jinli; Liu Jun; Lang Senyang; Zhou Dingbiao; Zhu Ke

    2000-01-01

    Objective: Eighty-five cases with multiple cerebral venous and venous sinuses thrombosis including the diagnosis and endovascular therapy were reported. Methods: The long T2 and short T1 signals in the related regions of multiple venous sinuses on MRI and prolonged blood circulation time of the brain with tortuous dilatation of vein in angiography were the important characteristics for the diagnosis. Of the 85 cases, the treatment procedures were consisted of injecting urokinase intermittently via common carotid artery and intra-sinus contact thrombolysis as well as warfarin intake orally. Results: Intracranial pressure of 80 cases reduced down between 230 and 300 mm H 2 O, and clinical deficits were markedly improved within 10 days. Re-angiography of 18 cases revealed recanalization partly in 5 cases and circulation time appeared near normal i 8 cases during one week after therapy. Conclusions: Combined intraarterial thrombolysis consecutively with general anticoagulation for the treatment of multiple thrombosis in cerebral venous sinuses may be one of the effective means

  16. Direct oral anticoagulants and venous thromboembolism

    Directory of Open Access Journals (Sweden)

    Massimo Franchini

    2016-09-01

    Full Text Available Venous thromboembolism (VTE, consisting of deep vein thrombosis and pulmonary embolism, is a major clinical concern associated with significant morbidity and mortality. The cornerstone of management of VTE is anticoagulation, and traditional anticoagulants include parenteral heparins and oral vitamin K antagonists. Recently, new oral anticoagulant drugs have been developed and licensed, including direct factor Xa inhibitors (e.g. rivaroxaban, apixaban and edoxaban and thrombin inhibitors (e.g. dabigatran etexilate. This narrative review focusses on the characteristics of these direct anticoagulants and the main results of published clinical studies on their use in the prevention and treatment of VTE.

  17. Pulmonary arterio-venous micro fistulae - Diagnostic

    International Nuclear Information System (INIS)

    Ebram, J.C.

    1989-01-01

    Four patients with pulmonary arterio-venous micro-fistulae - of which two were male (50%) - the ages varying from 10 to 43 (X sup(∼) = 22,7), were studied at the Cardiology Centre of the 6th Ward of Santa Casa da Misericordia Hospital in Rio de Janeiro. They were all basically suffering from Manson's Schistosomiasis, the hepato-splenic form in 3 cases (75%) and the Rendu Osler Weber disease with juvenile cirrhosis in 1 case (25%). All four of them had portal hypertension. The individual cases were clinically evaluate with X-rays, scintillographic and hemodynamic tests. (author)

  18. OAM mode converter in twisted fibers

    DEFF Research Database (Denmark)

    Usuga Castaneda, Mario A.; Beltran-Mejia, Felipe; Cordeiro, Cristiano

    2014-01-01

    We analyze the case of an OAM mode converter based on a twisted fiber, through finite element simulations where we exploit an equivalence between geometric and material transformations. The obtained converter has potential applications in MDM. © 2014 OSA.......We analyze the case of an OAM mode converter based on a twisted fiber, through finite element simulations where we exploit an equivalence between geometric and material transformations. The obtained converter has potential applications in MDM. © 2014 OSA....

  19. A new concept of thermionic converter

    International Nuclear Information System (INIS)

    Musa, G.

    1978-10-01

    The parameters of a new type of thermionic converter which has a number of concentric electrodes, is computed. The obtained theoretical efficiency of this new type of converter is nearly the efficiency of the ideal thermionic converter. The obtained results are explained by the reduction of the radiation loss from the emitter due to the electrode configuration. Efficiencies as high as 20% are expected from this type of converter now in construction. (author)

  20. Congenital Retinal Macrovessel and the Association of Retinal Venous Malformations With Venous Malformations of the Brain.

    Science.gov (United States)

    Pichi, Francesco; Freund, K Bailey; Ciardella, Antonio; Morara, Mariachiara; Abboud, Emad B; Ghazi, Nicola; Dackiw, Christine; Choudhry, Netan; Souza, Eduardo Cunha; Cunha, Leonardo Provetti; Arevalo, J Fernando; Liu, T Y Alvin; Wenick, Adam; He, Lingmin; Villarreal, Guadalupe; Neri, Piergiorgio; Sarraf, David

    2018-04-01

    Congenital retinal macrovessel (CRM) is a rarely reported venous malformation of the retina that is associated with venous anomalies of the brain. To study the multimodal imaging findings of a series of eyes with congenital retinal macrovessel and describe the systemic associations. In this cross-sectional multicenter study, medical records were retrospectively reviewed from 7 different retina clinics worldwide over a 10-year period (2007-2017). Patients with CRM, defined as an abnormal, large, macular vessel with a vascular distribution above and below the horizontal raphe, were identified. Data were analyzed from December 2016 to August 2017. Clinical information and multimodal retinal imaging findings were collected and studied. Pertinent systemic information, including brain magnetic resonance imaging findings, was also noted if available. Of the 49 included patients, 32 (65%) were female, and the mean (SD) age at onset was 44.0 (20.9) years. A total of 49 eyes from 49 patients were studied. Macrovessel was unilateral in all patients. Color fundus photography illustrated a large aberrant dilated and tortuous retinal vein in all patients. Early-phase frames of fluorescein angiography further confirmed the venous nature of the macrovessel in 40 of 40 eyes. Optical coherence tomography angiography, available in 17 eyes (35%), displayed microvascular capillary abnormalities around the CRM, which were more evident in the deep capillary plexus. Of the 49 patients with CRM, 39 (80%) did not illustrate any evidence of ophthalmic complications. Ten patients (20%) presented with retinal complications, typically an incidental association with CRM. Twelve patients (24%) were noted to have venous malformations of the brain with associated magnetic resonance imaging. Of these, location of the venous anomaly in the brain was ipsilateral to the CRM in 10 patients (83%) and contralateral in 2 patients (17%), mainly located in the frontal lobe in 9 patients (75%). Our study has

  1. Venous pump of the calf: a study of venous and muscular pressures.

    Science.gov (United States)

    Alimi, Y S; Barthelemy, P; Juhan, C

    1994-11-01

    Little data are available concerning the relation between the muscular pumping mechanism and the variation of superficial and deep venous pressure during normal action of the calf pump; therefore we undertook this study to determine the pressure values in three compartments of the calf and in the deep and the superficial venous system and to establish correlation between muscular and venous pressure. Nine healthy young women with a mean age of 23 years (range 19 to 28 years) were examined. In the same calf, a muscular catheter was placed in the deep posterior compartment (DPC), in the superficial posterior compartment (SPC), and in the anterior tibial compartment (ATC), and a vascular catheter was placed in the popliteal vein and in the greater saphenous vein (GSV). The five lines of pressure were simultaneously recorded in the following situations: at rest, during Valsalva maneuver, foot flexion, and foot extension. The situation was studied with the patient in the following positions: decubitus, sitting, standing, and squatting. A final continuous recording was carried out after the patient had been walking for 5 minutes. Mean values with standard errors of muscular and venous pressure were established in each situation. At rest and during Valsalva maneuver, the muscular pressures did not vary, whereas venous pressures increased significantly when the patient was sitting and standing. On the other hand, squatting was associated with a rise in the muscular and vein pressures. Foot flexion entailed a significant increase in the ATC pressure and a rise in the GSV pressure, whereas foot extension caused the DPC pressure to rise without venous pressure modifications. Walking was associated with an alternating increase in the DPC, SPC, GSV and popliteal vein pressures when the foot was compressed to floor followed by a significant decrease when the foot pressure was released. The variations in the deep and superficial venous pressures when the patient is sitting and

  2. Developmental venous anomalies with capillary stain: a subgroup of symptomatic DVAs?

    NARCIS (Netherlands)

    Roccatagliata, Luca; van den Berg, René; Soderman, Michael; Boulin, Anne; Condette-Auliac, Stéphanie; Rodesch, Georges

    2012-01-01

    Intracranial developmental venous anomalies (DVAs) are considered benign vascular dispositions; they are asymptomatic in the vast majority of cases. They represent extreme variations of the venous drainage and may rarely be responsible for focal venous ischemia leading to neurological dysfunction.

  3. Altered Venous Function during Long-Duration Spaceflights

    Directory of Open Access Journals (Sweden)

    Jacques-Olivier Fortrat

    2017-09-01

    Full Text Available Aims: Venous adaptation to microgravity, associated with cardiovascular deconditioning, may contribute to orthostatic intolerance following spaceflight. The aim of this study was to analyze the main parameters of venous hemodynamics with long-duration spaceflight.Methods: Venous plethysmography was performed on 24 cosmonauts before, during, and after spaceflights aboard the International Space Station. Venous plethysmography assessed venous filling and emptying functions as well as microvascular filtration, in response to different levels of venous occlusion pressure. Calf volume was assessed using calf circumference measurements.Results: Calf volume decreased during spaceflight from 2.3 ± 0.3 to 1.7 ± 0.2 L (p < 0.001, and recovered after it (2.3 ± 0.3 L. Venous compliance, determined as the relationship between occlusion pressure and the change in venous volume, increased during spaceflight from 0.090 ± 0.005 to 0.120 ± 0.007 (p < 0.01 and recovered 8 days after landing (0.071 ± 0.005, arbitrary units. The index of venous emptying rate decreased during spaceflight from −0.004 ± 0.022 to −0.212 ± 0.033 (p < 0.001, arbitrary units. The index of vascular microfiltration increased during spaceflight from 6.1 ± 1.8 to 10.6 ± 7.9 (p < 0.05, arbitrary units.Conclusion: This study demonstrated that overall venous function is changed during spaceflight. In future, venous function should be considered when developing countermeasures to prevent cardiovascular deconditioning and orthostatic intolerance with long-duration spaceflight.

  4. Spectrometric analog-to-digital converter

    International Nuclear Information System (INIS)

    Ormandzhiev, S.I.; Jordanov, V.T.

    1988-01-01

    Converter of digit-by-digit counterbalancing with slipping dial with number of channels equal to total number of states of the main digital-to-analog converter of digit-by-digit counterbalancing systems is presented. Algorithm for selection of digital-to-analog converters, which must be used by means of computer is suggested

  5. A novel series-resonant converter topology

    NARCIS (Netherlands)

    Tilgenkamp, N.V.; Haan, de S.W.H.; Huisman, H.

    1987-01-01

    A converter topology based on the principles of seriesresonant (SR) power conversion is described in which the input and output of this converter have one terminal in common, and the transformer is omitted. Both the underlying theory and associated waveforms are presented. The converter is suitable

  6. Radiographic signs of non-venous placement of intended central venous catheters in children

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Erin C. [Boston Children' s Hospital, Department of Radiology, Boston, MA (United States); Taylor, George A. [Boston Children' s Hospital, Department of Radiology, Boston, MA (United States); Harvard Medical School, Department of Radiology, Boston, MA (United States)

    2016-02-15

    Central venous catheters (CVCs) are commonly used in children, and inadvertent arterial or extravascular cannulation is rare but has potentially serious complications. To identify the radiographic signs of arterial placement of CVCs. We retrospectively reviewed seven cases of arterially malpositioned CVCs on chest radiograph. These cases were identified through departmental quality-assurance mechanisms and external consultation. Comparison of arterial cases was made with 127 age-matched chest radiographs with CVCs in normal, expected venous location. On each anteroposterior (AP) radiograph we measured the distance of the catheter tip from the right lateral border of the thoracic spine, and the angle of the vertical portion of the catheter relative to the midline. On each lateral radiograph we measured the angle of the vertical portion of each catheter relative to the anterior border of the thoracic spine. When bilateral subclavian catheters were present, the catheter tips were described as crossed, overlapping or uncrossed. On AP radiographs, arterially placed CVCs were more curved to the left, with catheter tip positions located farther to the left of midline than normal venous CVCs. When bilateral, properly placed venous catheters were present, all catheters crossed at the level of the superior vena cava (SVC). When one of the bilateral catheters was in arterial position, neither of the catheters crossed or the inter-catheter crossover distance was exaggerated. On lateral radiographs, there was a marked anterior angulation of the vertical portion of the catheter (mean angle 37 ± 15 standard deviation [SD] in arterial catheters versus 5.9 ± 8.3 SD in normally placed venous catheters). Useful radiographic signs suggestive of unintentional arterial misplacement of vascular catheters include leftward curvature of the vertical portion of the catheter, left-side catheter tip position, lack of catheter crossover on the frontal radiograph, as well as exaggerated

  7. Human cerebral venous outflow pathway depends on posture and central venous pressure

    Science.gov (United States)

    Gisolf, J; van Lieshout, J J; van Heusden, K; Pott, F; Stok, W J; Karemaker, J M

    2004-01-01

    Internal jugular veins are the major cerebral venous outflow pathway in supine humans. In upright humans the positioning of these veins above heart level causes them to collapse. An alternative cerebral outflow pathway is the vertebral venous plexus. We set out to determine the effect of posture and central venous pressure (CVP) on the distribution of cerebral outflow over the internal jugular veins and the vertebral plexus, using a mathematical model. Input to the model was a data set of beat-to-beat cerebral blood flow velocity and CVP measurements in 10 healthy subjects, during baseline rest and a Valsalva manoeuvre in the supine and standing position. The model, consisting of 2 jugular veins, each a chain of 10 units containing nonlinear resistances and capacitors, and a vertebral plexus containing a resistance, showed blood flow mainly through the internal jugular veins in the supine position, but mainly through the vertebral plexus in the upright position. A Valsalva manoeuvre while standing completely re-opened the jugular veins. Results of ultrasound imaging of the right internal jugular vein cross-sectional area at the level of the laryngeal prominence in six healthy subjects, before and during a Valsalva manoeuvre in both body positions, correlate highly with model simulation of the jugular cross-sectional area (R2 = 0.97). The results suggest that the cerebral venous flow distribution depends on posture and CVP: in supine humans the internal jugular veins are the primary pathway. The internal jugular veins are collapsed in the standing position and blood is shunted to an alternative venous pathway, but a marked increase in CVP while standing completely re-opens the jugular veins. PMID:15284348

  8. Molten-salt converter reactors

    International Nuclear Information System (INIS)

    Perry, A.M.

    1975-01-01

    Molten-salt reactors appear to have substantial promise as advanced converters. Conversion ratios of 0.85 to 0.9 should be attainable with favourable fuel cycle costs, with 235 U valued at $12/g. An increase in 235 U value by a factor of two or three ($10 to $30/lb. U 3 O 8 , $75/SWU) would be expected to increase the optimum conversion ratio, but this has not been analyzed in detail. The processing necessary to recover uranium from the fuel salt has been partially demonstrated in the MSRE. The equipment for doing this would be located at the reactor, and there would be no reliance on an established recycle industry. Processing costs are expected to be quite low, and fuel cycle optimization depends primarily on inventory and burnup or replacement costs for the fuel and for the carrier salt. Significant development problems remain to be resolved for molten-salt reactors, notably the control of tritium and the elimination of intergranular cracking of Hastelloy-N in contact with tellurium. However, these problems appear to be amenable to solution. It is appropriate to consider separating the development schedule for molten-salt reactors from that for the processing technology required for breeding. The Molten-Salt Converter Reactor should be a useful reactor in its own right and would be an advance towards the achievement of true breeding in thermal reactors. (author)

  9. Hybrid thermionic-photovoltaic converter

    Energy Technology Data Exchange (ETDEWEB)

    Datas, A. [Instituto de Energía Solar, Universidad Politécnica de Madrid, 28040 Madrid (Spain)

    2016-04-04

    A conceptual device for the direct conversion of heat into electricity is presented. This concept hybridizes thermionic (TI) and thermophotovoltaic (TPV) energy conversion in a single thermionic-photovoltaic (TIPV) solid-state device. This device transforms into electricity both the electron and photon fluxes emitted by an incandescent surface. This letter presents an idealized analysis of this device in order to determine its theoretical potential. According to this analysis, the key advantage of this converter, with respect to either TPV or TI, is the higher power density in an extended temperature range. For low temperatures, TIPV performs like TPV due to the negligible electron flux. On the contrary, for high temperatures, TIPV performs like TI due to the great enhancement of the electron flux, which overshadows the photon flux contribution. At the intermediate temperatures, ∼1650 K in the case of this particular study, I show that the power density potential of TIPV converter is twice as great as that of TPV and TI. The greatest impact concerns applications in which the temperature varies in a relatively wide range, for which averaged power density enhancement above 500% is attainable.

  10. Amino acid-based formula as a rescue strategy in feeding very-low-birth-weight infants with intrauterine growth restriction.

    Science.gov (United States)

    Raimondi, Francesco; Spera, Anna Maria; Sellitto, Maria; Landolfo, Francesca; Capasso, Letizia

    2012-05-01

    Very-low-birth-weight (VLBW) neonates may develop severe intolerance to standard preterm formula especially if they are associated with intrauterine growth restriction (IUGR). We tested the hypothesis that these infants may tolerate an elemental, amino acid-based formula as a rescue feeding strategy. In a prospective, case-control pilot study, we enrolled VLBW IUGR infants enterally fed with standard preterm formula (SPF) at daily increments of 16 mL/kg. If gastric residuals accounted for >70% of milk feed in the previous 24 hours, then feedings were temporarily withheld and then resumed with amino acid formula (AAF) increased at the same speed. Cases on AAF were compared to controls on SPF and with cases themselves while on SPF. Primary outcome was the time to reach full enteral feedings. Secondary outcomes were time on parenteral nutrition, time on central venous catheter, and formula tolerability based on the amount of gastric residual volume. Sixty-four infants (22 cases) were enrolled. Although during the total duration of nutrition, cases had worse primary and secondary outcomes, when on AAF, cases were comparable to controls in time to full enteral feeding (14.4 vs 14 days), time on parenteral nutrition, and time on central venous catheter. Cases on AAF and controls had similar gastric residual volumes. At day 3 after AAF introduction, cases had a significantly reduced number (%) of gastric residual volume >5 mL/kg over total number of feedings (5.6 vs 1.5%; P Growth at 12 months of corrected age was also comparable. In our population of VLBW IUGR newborns with severe feeding intolerance, a short course on AAF was a safe and effective means of nutritional rescue.

  11. Thrombophilia in children with venous thromboembolic disease.

    Science.gov (United States)

    Revel-Vilk, Shoshana; Kenet, Gili

    2006-01-01

    Venous thromboembolic events (VTEs) in children are usually associated with underlying clinical conditions such as central venous line, cancer and cardiac diseases. The objective of this review is to present the importance of thrombophilia to the occurrence of childhood VTE. The reported prevalence of thrombophilia in children with VTE varies extremely between 10% and 78% in different registries. The variation in the reported prevalence most probably reflects differences in the clinical characteristics of the children studied and differences in study designs. The initial management of children with thrombophilia and VTE is similar to those individuals who do not have a specific inherited thrombophilic risk factor, except in the rare events of homozygous deficiencies of prothrombotic coagulation proteins. The impact of thrombophilic markers on long-term therapy and outcome of children with VTE has not been completely clarified. According to the current guidelines for thrombophilia, all children with VTE should be tested for a full panel of genetic and acquired prothrombotic traits. However, re-evaluation of co-morbid risk factors other than thrombophilic markers and careful consideration of the prognostic value of thrombophilic markers might help to change future attitude from the rigidity of current guidelines to more rational schemes.

  12. MRI and CT in cerebral venous thrombosis

    International Nuclear Information System (INIS)

    Surur, Alberto; Marangoni, Alberto; Devallis, Juan P.; Galvez, Vasco; Marchegiani, Silvio; Galletti, Cayetano; Martin, Juan J.

    2004-01-01

    Purpose: The veno-occlusive encephalic disease is a neurologic disorder of difficult clinic diagnostic almost always. This clinic situation presents a high morbi-mortality range without an early and precise diagnostic. With the use of Helical Computed Tomography (HCT) and Angio Magnetic Resonance Image (AMRI) the diagnosis has became more effective in the encephalic venous thrombosis. Methods: Fourteen patients with clinical suspicion on encephalic venous thrombosis using non-invasive techniques as HCT and AMRI were studied. Results: In all these cases we were able to arrive at the exact etiologic diagnostic using these techniques associated to the clinics findings, without needing the use of another invasive method like Angiography. Conclusion: The results were satisfactory for definitive diagnosis, without Angiography. When a patient has a high suspicion of veno-occlusive disease the neuro radiologic examination in the urgency is a very important fact and using HCT and AMRI as the first examinations techniques it is possible to obtain good results without most aggressive techniques. (author)

  13. Knowledge and practice of prophylaxis of deep venous thrombosis ...

    African Journals Online (AJOL)

    2015-09-03

    Sep 3, 2015 ... Kesieme, et al.: Knowledge and practice of prophylaxis of deep venous thrombosis: A survey. 171. Nigerian Journal of Clinical Practice • Mar-Apr 2016 • Vol 19 • Issue 2. Introduction. Venous thromboembolism (VTE) is an important but preventable cause of morbidity and mortality among surgical patients.

  14. Counteracting venous stasis during acute lower leg immobilization.

    NARCIS (Netherlands)

    Poelkens, F.; Thijssen, D.H.J.; Kersten, B.T.P.; Scheurwater, H.; Laarhoven, E.W. van; Hopman, M.T.E.

    2006-01-01

    AIM: During lower limb immobilization, patients are at risk to develop deep venous thrombosis. Recently, a water-pad was developed that should counteract venous stasis. The water-pad, located under the plaster, mobilizes water from the foot to the calf during weight bearing and, thereby, imitates

  15. Septic Mesenteric Venous Thrombophlebitis: A Rare Complication of Acute Appendicitis

    Directory of Open Access Journals (Sweden)

    Stylianos Kykalos

    2011-01-01

    Full Text Available Mesenteric venous thrombophlebitis represents a very rare complication of acute appendicitis. Based on the findings of a 45-year-old patient with mesenteric venous thrombophlebitis due to acute appendicitis, we herein describe the diagnostic difficulties and therapeutic options in this uncommon disease. The treatment in our case consisted of simple appendectomy and perioperative anticoagulation therapy.

  16. Rivaroxaban or Aspirin for Extended Treatment of Venous Thromboembolism

    NARCIS (Netherlands)

    Weitz, Jeffrey I.; Lensing, Anthonie W. A.; Prins, Martin H.; Bauersachs, Rupert; Beyer-Westendorf, Jan; Bounameaux, Henri; Brighton, Timothy A.; Cohen, Alexander T.; Davidson, Bruce L.; Decousus, Hervé; Freitas, Maria C. S.; Holberg, Gerlind; Kakkar, Ajay K.; Haskell, Lloyd; van Bellen, Bonno; Pap, Akos F.; Berkowitz, Scott D.; Verhamme, Peter; Wells, Philip S.; Prandoni, Paolo; Bianchi, Alessandra; Brighton, Tim; Carroll, Patrick; Chong, Beng; Chunilal, Sanjeev; Coughlin, Paul; Curnow, Jennifer; Jackson, David; Tran, Huyen; Ward, Chris; Brodmann, Marianne; Kyrle, Paul; Marschang, Peter; Petkov, Ventzislav; Hainaut, Philippe; Jordens, Paul; Vandekerkhof, Jos; Wautrecht, Jean-Claude; Annichino-Bizzacchi, Joyce; Correa, Joao; Cukier, Alberto; Freire, Antonio; Pereira, Adamastor; Porto, Carmen; Sacilotto, Roberto; Vasconcelos Costa, Agenor; Della Siega, Anthony; Dolan, Sean; Le Gal, Gré goire; Middeldorp, Saskia

    2017-01-01

    BACKGROUND Although many patients with venous thromboembolism require extended treatment, it is uncertain whether it is better to use full- or lower-intensity anticoagulation therapy or aspirin. METHODS In this randomized, double-blind, phase 3 study, we assigned 3396 patients with venous

  17. Regular sports activities decrease the risk of venous thrombosis

    NARCIS (Netherlands)

    van Stralen, K. J.; le Cessie, S.; Rosendaal, F. R.; Doggen, C. J. M.

    2007-01-01

    BACKGROUND: Stasis of the blood has been postulated as a major cause of venous thrombosis. However, little is known about the effect of stimulating the blood flow in order to prevent venous thrombosis through, for example, sports activities. OBJECTIVES: In a large population-based case-control study

  18. Thrombin Avtivable Fibrinolysis Inhibitor in Venous and Arterial Thrombosis

    NARCIS (Netherlands)

    E.L.E. de Bruijne

    2011-01-01

    textabstractVenous and arterial thromboses are major causes of morbidity and mortality. Venous thrombosis is the result of pathological occlusive clot formation in the veins. It occurs mainly in the deep veins of the leg (deep vein thrombosis), from which parts of the clot frequently embolize to the

  19. Edoxaban versus warfarin for the treatment of symptomatic venous thromboembolism

    NARCIS (Netherlands)

    Büller, Harry R; Décousus, Hervé; Grosso, Michael A; Mercuri, Michele; Middeldorp, Saskia; Prins, Martin H; Raskob, Gary E; Schellong, Sebastian M; Schwocho, Lee; Segers, Annelise; Shi, Minggao; Verhamme, Peter; Wells, Phil; Kamphuisen, P.W.

    2013-01-01

    BACKGROUND: Whether the oral factor Xa inhibitor edoxaban can be an alternative to warfarin in patients with venous thromboembolism is unclear. METHODS: In a randomized, double-blind, noninferiority study, we randomly assigned patients with acute venous thromboembolism, who had initially received

  20. Edoxaban versus Warfarin for the Treatment of Symptomatic Venous Thromboembolism

    DEFF Research Database (Denmark)

    Büller, Harry R; Décousus, Hervé; Grosso, Michael A

    2013-01-01

    Whether the oral factor Xa inhibitor edoxaban can be an alternative to warfarin in patients with venous thromboembolism is unclear.......Whether the oral factor Xa inhibitor edoxaban can be an alternative to warfarin in patients with venous thromboembolism is unclear....

  1. Deep venous thrombosis like puerperium complication: two cases

    International Nuclear Information System (INIS)

    Martin Gomez, J.I.; Larena Iturbe, J.A.; Zuazo Ojeda, M.A.; Pena Sarnago, J.M.

    1994-01-01

    Deep venous thrombosis, especially that of the ovarian vein, is a rare, potentially fatal complication that can present during the puerperium, its clinical diagnosis is not easy, thus dangerously delaying specific treatment. Two cases are presented of deep venous thrombosis diagnosed on the basis of computerized tomography (CT) in puerperal patients with symptoms of postpartum pain and fever. (Author) 9 refs

  2. Mechanical thrombectomy: an alternative for treating cerebral venous sinus thrombosis.

    Science.gov (United States)

    Izura Gómez, Marta; Misis Del Campo, Maite; Puyalto de Pablo, Paloma; Castaño Duque, Carlos

    2018-01-01

    We report the use of mechanical venous thrombectomy in 2 cases of cerebral venous sinus thrombosis in which the usual first-choice treatment with systemic anticoagulants was contraindicated. Our aim is to present this treatment as an alternative to consider when anticoagulants therapy is too risky or is contraindicated in critically ill patients.

  3. Valuing Convertible Bonds Based on LSRQM Method

    Directory of Open Access Journals (Sweden)

    Jian Liu

    2014-01-01

    Full Text Available Convertible bonds are one of the essential financial products for corporate finance, while the pricing theory is the key problem to the theoretical research of convertible bonds. This paper demonstrates how to price convertible bonds with call and put provisions using Least-Squares Randomized Quasi-Monte Carlo (LSRQM method. We consider the financial market with stochastic interest rates and credit risk and present a detailed description on calculating steps of convertible bonds value. The empirical results show that the model fits well the market prices of convertible bonds in China’s market and the LSRQM method is effective.

  4. Complexity in Acid-Base Titrations: Multimer Formation Between Phosphoric Acids and Imines.

    Science.gov (United States)

    Malm, Christian; Kim, Heejae; Wagner, Manfred; Hunger, Johannes

    2017-08-10

    Solutions of Brønsted acids with bases in aprotic solvents are not only common model systems to study the fundamentals of proton transfer pathways but are also highly relevant to Brønsted acid catalysis. Despite their importance the light nature of the proton makes characterization of acid-base aggregates challenging. Here, we track such acid-base interactions over a broad range of relative compositions between diphenyl phosphoric acid and the base quinaldine in dichloromethane, by using a combination of dielectric relaxation and NMR spectroscopy. In contrast to what one would expect for an acid-base titration, we find strong deviations from quantitative proton transfer from the acid to the base. Even for an excess of the base, multimers consisting of one base and at least two acid molecules are formed, in addition to the occurrence of proton transfer from the acid to the base and simultaneous formation of ion pairs. For equimolar mixtures such multimers constitute about one third of all intermolecular aggregates. Quantitative analysis of our results shows that the acid-base association constant is only around six times larger than that for the acid binding to an acid-base dimer, that is, to an already protonated base. Our findings have implications for the interpretation of previous studies of reactive intermediates in organocatalysis and provide a rationale for previously observed nonlinear effects in phosphoric acid catalysis. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  5. Electrolyte and Acid-Base Disturbances in End-Stage Liver Disease: A Physiopathological Approach.

    Science.gov (United States)

    Jiménez, José Víctor; Carrillo-Pérez, Diego Luis; Rosado-Canto, Rodrigo; García-Juárez, Ignacio; Torre, Aldo; Kershenobich, David; Carrillo-Maravilla, Eduardo

    2017-08-01

    Electrolyte and acid-base disturbances are frequent in patients with end-stage liver disease; the underlying physiopathological mechanisms are often complex and represent a diagnostic and therapeutic challenge to the physician. Usually, these disorders do not develop in compensated cirrhotic patients, but with the onset of the classic complications of cirrhosis such as ascites, renal failure, spontaneous bacterial peritonitis and variceal bleeding, multiple electrolyte, and acid-base disturbances emerge. Hyponatremia parallels ascites formation and is a well-known trigger of hepatic encephalopathy; its management in this particular population poses a risky challenge due to the high susceptibility of cirrhotic patients to osmotic demyelination. Hypokalemia is common in the setting of cirrhosis: multiple potassium wasting mechanisms both inherent to the disease and resulting from its management make these patients particularly susceptible to potassium depletion even in the setting of normokalemia. Acid-base disturbances range from classical respiratory alkalosis to high anion gap metabolic acidosis, almost comprising the full acid-base spectrum. Because most electrolyte and acid-base disturbances are managed in terms of their underlying trigger factors, a systematic physiopathological approach to their diagnosis and treatment is required.

  6. Increased venous thrombosis incidence in pregnancies after in vitro fertilization

    DEFF Research Database (Denmark)

    Hansen, Anette Tarp; Kesmodel, U S; Juul, S

    2014-01-01

    STUDY QUESTION Is venous thrombosis risk increased in pregnancies after in vitro fertilization? SUMMARY ANSWER The venous thrombosis incidence was significantly increased in pregnancies after in vitro fertilization; especially in the first trimester and in the first 6 weeks post-partum. WHAT...... IS KNOWN ALREADY In vitro fertilization without pregnancy is not associated with increased venous thrombosis incidence. STUDY DESIGN, SIZE, DURATION This national register-based cohort study covered the period from 1995 to 2005. PARTICIPANTS/MATERIALS, SETTING, METHODS All Danish pregnancies conceived...... by in vitro fertilization (n = 18 787) were included. Venous thrombosis incidence rates in pregnancies after in vitro fertilization were compared with venous thrombosis incidence rates in reference pregnancies, by calculating incidence rate ratios. MAIN RESULTS AND THE ROLE OF CHANCE In total, 48 cases were...

  7. Determination of intestinal viability by Doppler ultrasonography in venous infarction.

    Science.gov (United States)

    Cooperman, M; Martin, E W; Carey, L C

    1980-01-01

    The accuracy of Doppler ultrasound in predicting the viability of ischemic intestine secondary to venous obstruction was assessed. Twenty loops of ischemic intestine were created in dogs by temporarily obstructing venous return from the bowel. Doppler arterial flow signals within the intestine quickly disappeared following venous occlusion. In ten segments, arterial signals promptly returned following release of venous occlusion. Nine of these ten segments were viable at reoperation 24 hours later. In ten segments, no arterial signals could be detected following release of venous occlusion, and only one segment proved to be viable. Doppler ultrasound findings were far more accurate in distinguishing between viable and nonviable intestine thatn were clinical guides to intestinal viability. PMID:7352777

  8. Converting pest insects into food

    DEFF Research Database (Denmark)

    Offenberg, Hans Joachim; Wiwatwittaya, Decha

    2010-01-01

    Canopy dwelling weaver ants (Oecophylla spp.) are used to control a variety of pests in a number of tropical tree crops. What is less familiar is the existence of commercial markets where these ants and their brood are sold for (i) human consumption, (ii) pet food or (iii) traditional medicine...... on management, 32-115 kg ant brood (mainly new queens) was harvested per ha per year without detrimental effect on colony survival and worker ant densities. This suggest that ant biocontrol and ant harvest can be sustainable integrated in plantations and double benefits derived. As ant production is fuelled...... by pest insects, problematic pests are converted into food and additional earnings. To assess the profitability of providing additional food for the ants, O. smaragdina food conversion efficiency (ECI) was estimated in the laboratory. This estimate suggests the feeding of weaver ants in ant farms...

  9. Efficiency of Capacitively Loaded Converters

    DEFF Research Database (Denmark)

    Andersen, Thomas; Huang, Lina; Andersen, Michael A. E.

    2012-01-01

    This paper explores the characteristic of capacitance versus voltage for dielectric electro active polymer (DEAP) actuator, 2kV polypropylene film capacitor as well as 3kV X7R multi layer ceramic capacitor (MLCC) at the beginning. An energy efficiency for capacitively loaded converters...... is introduced as a definition of efficiency. The calculated and measured efficiency curves for charging DEAP actuator, polypropylene film capacitor and X7R MLCC are provided and compared. The attention has to be paid for the voltage dependent capacitive load, like X7R MLCC, when evaluating the charging...... polypropylene film capacitor can be the equivalent capacitive load. Because of the voltage dependent characteristic, X7R MLCC cannot be used to replace the DEAP actuator. However, this type of capacitor can be used to substitute the capacitive actuator with voltage dependent property at the development phase....

  10. THE AZYGOS VENOUS SYSTEM AND ITS ANATOMICAL VARIATIONS

    Directory of Open Access Journals (Sweden)

    Madiki Sudhakara Rao

    2016-06-01

    Full Text Available AIMS AND OBJECTIVES Azygos veins are important cavocaval and portacaval junctions, which form a collateral circulation in caval vein occlusion and in portal hypertension, cirrhosis of liver. The unpaired azygos venous system consists of azygos vein, hemiazygos vein and accessory azygos vein. This system of veins, along with its mediastinal, bronchial and oesophageal tributaries drains most of the body wall of trunk, namely posterior abdominal and thoracic wall. Anatomical variations of this unpaired azygos venous system are clinically important. AIMS To study and report the occurrence of anatomical variations of the unpaired azygos venous system in the region of East Godavari District, Andhra Pradesh (India. METHODS The present study was carried out in the Department of Anatomy, KIMS & RF, Amalapuram and G.S.L. Medical College, Rajahmundry over a period of 2 years. The present study was conducted on 60 cadavers (irrespective of age and sex. The entire course of the azygos venous system in these 60 cadavers was carefully observed and documented. RESULTS Anatomical variations were present in 16.66% of cases, out of which three distinct types were identified. 6.6% exhibited two separate azygos venous systems with no communications, 5% with communication between the left brachiocephalic vein and the azygos vein and 5% presence of post-aortic venous channels. CONCLUSION Variations of azygos venous system may be wrongly dubbed as aneurysm, lymphadenopathy or other abnormalities while reporting a CT scan of mediastinum. Venous anomalies are also detected only during surgery. The most troublesome intraoperative hazard is haemorrhage, which is mainly of venous origin. To avoid such situations is to have an awareness and knowledge of the expected venous anomalies.

  11. Cerebrofacial venous metameric syndrome (CVMS) 3: Sturge-Weber syndrome with bilateral lymphatic/venous malformations of the mandible

    International Nuclear Information System (INIS)

    Ramli, N.; Sachet, M.; Bao, C.; Lasjaunias, P.

    2003-01-01

    We present a case of Sturge-Weber syndrome with a bilateral lymphatic/venous malformation of the mandible. Modern biology suggests an explanation for such a case. The classification of cerebrofacial venous metameric syndromes (CVMS) enables us to recognise this lesion as involving the most caudal of the cranial metamere (CVMS 3). (orig.)

  12. Venous, Arterialized-Venous, or Capillary Glucose Reference Measurements for the Accuracy Assessment of a Continuous Glucose Monitoring System

    NARCIS (Netherlands)

    Kropff, Jort; van Steen, Sigrid C.; deGraaff, Peter; Chan, Man W.; van Amstel, Rombout B. E.; DeVries, J. Hans

    2017-01-01

    Background: Different reference methods are used for the accuracy assessment of continuous glucose monitoring (CGM) systems. The effect of using venous, arterialized-venous, or capillary reference measurements on CGM accuracy is unclear. Methods: We evaluated 21 individuals with type 1 diabetes

  13. Systemic treatments for the prevention of venous thrombo-embolic events in paediatric cancer patients with tunnelled central venous catheters

    NARCIS (Netherlands)

    Schoot, Reineke A.; Kremer, Leontien C. M.; van de Wetering, Marianne D.; van Ommen, Cornelia H.

    2013-01-01

    Venous thrombo-embolic events (VTEs) occur in 2.2% to 14% of paediatric cancer patients and cause significant morbidity and mortality. The malignant disease itself, the cancer treatment and the presence of central venous catheters (CVCs) increase the risk of VTE. The primary objective of this review

  14. Penile venous surgery for treating erectile dysfunction: Past, present, and future perspectives with regard to new insights in venous anatomy

    Directory of Open Access Journals (Sweden)

    Cheng-Hsing Hsieh

    2016-06-01

    Full Text Available In the physiologic model of normal erectile function, a healthy veno-occlusive mechanism is essential to initiate and maintain a rigid erection. The surgical treatment of patients with venous leakage, which is synonymous with corporoveno-occlusive dysfunction (CVOD, was based on the decreased venous outflow during the erection process. The initial reports of short-term results were promising, but the long-term benefits of penile venous ligation surgery were limited. Most clinical guideline panels concluded that surgeries performed in an attempt to limit the venous outflow of the penis were not recommended. Consequently, this surgery was nearly abandoned in most medical societies worldwide. These unfavorable postoperative outcomes seemed attributable to the indispensable usage of electrocautery and insufficient venous management, based on conventional penile venous anatomy. Advances in better understanding of human penile venous anatomy has enabled the development of refined penile venous stripping surgery. The thorough stripping surgery is an even more radical procedure, which is an even more radical procedure, and seems to be a viable option for the treatment of CVOD, however, there is still a need for further study with well-defined diagnostic criteria, and standardized patient and partner outcome assessment.

  15. Effect of acute acid loading on acid-base and calcium metabolism

    DEFF Research Database (Denmark)

    Osther, Palle J

    2006-01-01

    OBJECTIVE: To investigate the acid-base and calcium metabolic responses to acute non-carbonic acid loading in idiopathic calcium stone-formers and healthy males using a quantitative organ physiological approach. MATERIAL AND METHODS: Five-h ammonium chloride loading studies were performed in 12...... male recurrent idiopathic calcium stone-formers and 12 matched healthy men using a randomized, placebo-controlled, cross-over design. Arterialized capillary blood, serum and urine were collected hourly for measurement of electrolytes, ionized calcium, magnesium, phosphate, parathyroid hormone and acid-base...... status. Concentrations of non-metabolizable base (NB) and acid (NA) were calculated from measured concentrations of non-metabolizable ions. RESULTS: The extracellular acid-base status in the stone-formers during basal conditions and acid loading was comparable to the levels in the healthy controls...

  16. Potentiometric Measurement of Transition Ranges and Titration Errors for Acid/Base Indicators

    Science.gov (United States)

    Flowers, Paul A.

    1997-07-01

    Sophomore analytical chemistry courses typically devote a substantial amount of lecture time to acid/base equilibrium theory, and usually include at least one laboratory project employing potentiometric titrations. In an effort to provide students a laboratory experience that more directly supports their classroom discussions on this important topic, an experiment involving potentiometric measurement of transition ranges and titration errors for common acid/base indicators has been developed. The pH and visually-assessed color of a millimolar strong acid/base system are monitored as a function of added titrant volume, and the resultant data plotted to permit determination of the indicator's transition range and associated titration error. Student response is typically quite positive, and the measured quantities correlate reasonably well to literature values.

  17. Imaging Characteristics of Venous Parenchymal Abnormalities.

    Science.gov (United States)

    Arnoux, Audrey; Triquenot-Bagan, Aude; Andriuta, Daniela; Wallon, David; Guegan-Massardier, Evelyne; Leclercq, Claire; Martinaud, Olivier; Castier-Amouyel, Mélody; Godefroy, Olivier; Bugnicourt, Jean-Marc

    2017-12-01

    There are few published data on the patterns of parenchymal imaging abnormalities in a context of cerebral venous thrombosis (CVT). The objectives of the present study were to describe the patterns of parenchymal lesions associated with CVT and to determine the lesion sites. We included 44 consecutively hospitalized patients with CVT and parenchymal lesions on magnetic resonance imaging. The diagnosis of CVT had been confirmed by magnetic resonance imaging/magnetic resonance venography. Magnetic resonance imaging patterns for CVT were retrospectively analyzed with regard to the lesion's type, shape, and site. The most frequent stroke subtype was hemorrhagic ischemia (in 56.8% of cases), followed by intracerebral hematoma (in 22.72% of cases) and nonhemorrhagic ischemia (in 20.45% of cases). Although there were no significant differences between these 3 groups with regard to the clinical and radiological characteristics, we observed a nonsignificant trend ( P =0.08) toward a shorter time interval between hospital admission and magnetic resonance imaging for nonhemorrhagic stroke. The CVT parenchymal abnormalities were centered on 6 main foci and were related to the site of venous occlusion: (1) the inferior parietal lobule (n=20; 44.5%), associated mainly with occlusion of the transverse sinus (n=10) or pure cortical veins (n=10); (2) the inferior and posterior temporal regions (n=10; 22.75%), associated mainly with occlusion of the transverse sinus (n=9); (3) the parasagittal frontal region (n=6; 13.6%), associated mainly with occlusion of the superior sagittal sinus (n=4) or the transverse sinus (n=4); (4) the thalamus (n=5; 11.3%) associated with occlusion of the straight sinus (n=5); (5) the cerebellar hemisphere (n=2; 4.5%), associated in both cases with occlusion of the transverse sinus; and (6) the deep hemispheric regions (n=3; 6.8%), associated with occlusion of the superior sagittal sinus in all cases. Parenchymal lesions caused by CVT display specific

  18. VENOUS INSUFFICIENCY AND THROMBOEMBOLIC DISEASE IN BARIATRIC SURGERY PATIENTS

    Directory of Open Access Journals (Sweden)

    Bonno van BELLEN

    2013-09-01

    Full Text Available Context Morbid obesity is associated with various co-morbidities, including chronic venous insufficiency. Bariatric surgery is the only effective treatment for morbid obesity, but with potential risks and possible complications, including venous thromboembolism. Objective To determine the prevalence of clinical and ultrasonographic signs of chronic venous insufficiency in morbid obese patients in preparation for bariatric surgery and the incidence of post-operative venous thromboembolic disease. Methods Patients on work-up for bariatric surgery of Centro Terapêutico Especializado em Fígado (CETEFI and Pro-Gastro surgical teams of the Hospital Beneficência Portuguesa de São Paulo were included. The analysed data were pre-operative findings for venous insufficiency (CEAP - clinical, etiological, anatomical, physiopathologic - classification and venous ultrassonographic findings, type of surgery (open or laparoscopic, abdominal circumference, body mass index (BMI and post-operative ultrassonography search for venous insufficiency and deep venous thrombosis. Results Between March 2007 and December 2009, 95 patients candidates for bariatric surgery had clinical and duplex scan evaluation of the lower limbs venous system. Of the 95 patients, 53 were submitted to the surgical procedure. There was a predominance of women (77.9%, the average age was 38.5 years, average preoperative weight 124.6 kg and average BMI of 45.5 kg/m2. Regarding obesity, 16.8% were obese, and 83.1% were morbidly obese. In relation to the venous findings, 86.3% of the patients did fit CEAP classification less than 3 and 13.7% greater than or equal to 3. Among the post-operative complications, there were four cases of wound infection. Three patients developed post-operative distal venous thrombosis (7.5%, but no one had clinically manifested pulmonary embolism. Conclusion No relation between BMI, CEAP classification and venous ultrassonographic findings were found. Although

  19. Acid-Base Properties of Azo Dyes in Solution Studied Using Spectrophotometry and Colorimetry

    Science.gov (United States)

    Snigur, D. V.; Chebotarev, A. N.; Bevziuk, K. V.

    2018-03-01

    Colorimetry and spectrophotometry with chemometric data processing were used to study the acid-base properties of azo dyes in aqueous solution. The capabilities of both methods were compared. Ionization constants of all the functional groups of the azo compounds studied could be determined relative to the change in the specific color difference depending on the acidity of the medium. The colorimetric functions of ion-molecular forms of azo compounds used as an analytical signal allow us to obtain complete information on the acid-base equilibrium in a wide acidity range.

  20. Design, synthesis and structure of new potential electrochemically active boronic acid-based glucose sensors

    DEFF Research Database (Denmark)

    Norrild, Jens Chr.; Søtofte, Inger

    2002-01-01

    In the course of our investigations on new boronic acid based carbohydrate sensors three new boronic acids 3, 7 and 11 containing a ferrocene moiety were synthesised. Their design includes an intramolecular B-N bonding motif in order to facilitate binding at physiological pH. We report the synthe......In the course of our investigations on new boronic acid based carbohydrate sensors three new boronic acids 3, 7 and 11 containing a ferrocene moiety were synthesised. Their design includes an intramolecular B-N bonding motif in order to facilitate binding at physiological pH. We report...

  1. Mobile Clinical Decision Support System for Acid-base Balance Diagnosis and Treatment Recommendation.

    Science.gov (United States)

    Mandzuka, Mensur; Begic, Edin; Boskovic, Dusanka; Begic, Zijo; Masic, Izet

    2017-06-01

    This paper presents mobile application implementing a decision support system for acid-base disorder diagnosis and treatment recommendation. The application was developed using the official integrated development environment for the Android platform (to maximize availability and minimize investments in specialized hardware) called Android Studio. The application identifies disorder, based on the blood gas analysis, evaluates whether the disorder has been compensated, and based on additional input related to electrolyte imbalance, provides recommendations for treatment. The application is a tool in the hands of the user, which provides assistance during acid-base disorders treatment. The application will assist the physician in clinical practice and is focused on the treatment in intensive care.

  2. Nucleic Acid-based Detection of Bacterial Pathogens Using Integrated Microfluidic Platform Systems

    Directory of Open Access Journals (Sweden)

    Carl A. Batt

    2009-05-01

    Full Text Available The advent of nucleic acid-based pathogen detection methods offers increased sensitivity and specificity over traditional microbiological techniques, driving the development of portable, integrated biosensors. The miniaturization and automation of integrated detection systems presents a significant advantage for rapid, portable field-based testing. In this review, we highlight current developments and directions in nucleic acid-based micro total analysis systems for the detection of bacterial pathogens. Recent progress in the miniaturization of microfluidic processing steps for cell capture, DNA extraction and purification, polymerase chain reaction, and product detection are detailed. Discussions include strategies and challenges for implementation of an integrated portable platform.

  3. Mutagenicity of irradiated solutions of nuclei acid bases and nucleosides in Salmonella typhimurium

    International Nuclear Information System (INIS)

    Wilmer, J.; Schubert, J.

    1981-01-01

    Solutions of nucleic acid bases, nucleosides and a nucleotide, saturated with either N 2 , N 2 O or O 2 , were irradiated and tested for mutagenicity towards Salmonella typhimurium, with and without pre-incubation. Irradiated solutions of the nuclei acid bases were all non-mutagenic. Irradiated solutions of the nucleosides showed mutagenicity in S. typhimurium TA100 (pre-incubation assay). Generally, the mutagenicity followed the order: N 2 O > N 2 > O 2 . The results show that the formation of mutagenic radiolytic products is initiated by attack of mainly solutions of the nucleotide thymidine-5'-monophosphate, no mutagenicity could be detected. (orig.)

  4. Acid-base status after whole-body irradiation in dairy cows

    International Nuclear Information System (INIS)

    Schaefer, M.; Koch, F.; Dyrba, W.; Kirbach, M.

    1989-01-01

    Whole-body irradiation using 9 MeV X-rays of a linear accelerator of 10 clinically healthy lactating cows aged between 3.5 and 8 years produced an acute radiation syndrome in the LD 100/30 range. Blood analysis 1 day after irradiation showed a compensated metabolic acidosis with a low renal net acid-base excretion and hyerphosphaturia. Later the acid-base status indicated a differently marked metabolic alkalosis. In the main reaction period acidotic disturbances occurred, which partially were camouflaged by respiratory alkalosis. (author)

  5. [Disorders of the acid-base balance and the anion gap].

    Science.gov (United States)

    Kimmel, Martin; Alscher, Mark Dominik

    2016-10-01

    The regulation of the acid-base balance and pH is critical for the organism. The most important buffer system is CO 2 / HCO 3 - . The kidney controls systemic bicarbonate and therefore the metabolic regulation and the lung is relevant for respiratory regulation by an effective CO 2 elimination. There are four acid-base disorders with two metabolic and two respiratory disorders (acidosis and alkalosis). The anion gap enables a further workup of metabolic acidosis. © Georg Thieme Verlag KG Stuttgart · New York.

  6. Essentials in the diagnosis of acid-base disorders and their high altitude application.

    Science.gov (United States)

    Paulev, P E; Zubieta-Calleja, G R

    2005-09-01

    This report describes the historical development in the clinical application of chemical variables for the interpretation of acid-base disturbances. The pH concept was already introduced in 1909. Following World War II, disagreements concerning the definition of acids and bases occurred, and since then two strategies have been competing. Danish scientists in 1923 defined an acid as a substance able to give off a proton at a given pH, and a base as a substance that could bind a proton, whereas the North American Singer-Hasting school in 1948 defined acids as strong non-buffer anions and bases as non-buffer cations. As a consequence of this last definition, electrolyte disturbances were mixed up with real acid-base disorders and the variable, strong ion difference (SID), was introduced as a measure of non-respiratory acid-base disturbances. However, the SID concept is only an empirical approximation. In contrast, the Astrup/Siggaard-Andersen school of scientists, using computer strategies and the Acid-base Chart, has made diagnosis of acid-base disorders possible at a glance on the Chart, when the data are considered in context with the clinical development. Siggaard-Andersen introduced Base Excess (BE) or Standard Base Excess (SBE) in the extracellular fluid volume (ECF), extended to include the red cell volume (eECF), as a measure of metabolic acid-base disturbances and recently replaced it by the term Concentration of Titratable Hydrogen Ion (ctH). These two concepts (SBE and ctH) represent the same concentration difference, but with opposite signs. Three charts modified from the Siggaard-Andersen Acid-Base Chart are presented for use at low, medium and high altitudes of 2500 m, 3500 m, and 4000 m, respectively. In this context, the authors suggest the use of Titratable Hydrogen Ion concentration Difference (THID) in the extended extracellular fluid volume, finding it efficient and better than any other determination of the metabolic component in acid-base

  7. Expression of the Components of the Renin-Angiotensin System in Venous Malformation

    Directory of Open Access Journals (Sweden)

    Sam eSiljee

    2016-05-01

    Full Text Available Background Venous malformation (VM is the most common form of vascular malformation, consisting of a network of thin-walled ectatic venous channels with deficient or absent media. This study investigated the expression of the components of the renin-angiotensin system (RAS, namely (prorenin receptor (PRR, angiotensin converting enzyme (ACE, angiotensin II receptor 1 (ATIIR1 and angiotensin II receptor 2 (AIITR2 in subcutaneous (SC and intramuscular (IM VM. Materials and Methods SC (n=7 and IM (n=7 VM were analyzed for the expression of PRR, ACE, ATIIR1, and ATIIR2 using 3,3-diaminobenzidine (DAB and immunofluorescent (IF immunohistochemical (IHC staining and NanoString gene expression analysis. Results IHC staining showed expression of PRR, ACE, ATIIR1 and faint expression of ATIIR2 in the endothelium of SC and IM VM. Furthermore, ATIIR2 was expressed by cells away from the endothelium in both SC and IM VM lesions examined. NanoString analysis demonstrated the presence of PRR, ACE and ATIIR1 but not ATIIR2.Conclusions The presence of PRR, ACE, ATIIR1 and potentially ATIIR2, in both SC and IM VM suggests a role for the RAS in the biology of VM. This novel finding may lead to a mechanism-based therapy for VM.

  8. Deep Venous Thrombosis Associated With Inferior Vena Cava Abnormalities And Hypoplastic Kidney In Siblings

    Directory of Open Access Journals (Sweden)

    Duicu Carmen

    2016-06-01

    Full Text Available Congenital inferior vena cava anomalies have a reduced frequency in general population, many times being an asymptomatic finding. Patients caring such anomalies are at risk to develop deep vein thrombosis. In this paper, we present 2 siblings with deep venous thrombosis and inferior vena cava abnormalities, with a symptomatic onset at similar age. The inferior vena cava abnormality was documented by an angio-CT in each case. The thrombophilic workup was negative. Patients were treated with conservative therapy: low molecular weight heparin anticoagulants converted later to oral anticoagulant with resolution of symptoms and disappearance of the thrombus. Finally, in the absence of any risk factor in a young patient admitted with deep vein thrombosis investigations to exclude inferior vena cava anomalies are mandatory.

  9. Primary prophylaxis of venous thromboembolism in children.

    Science.gov (United States)

    Cole, Catherine H

    2010-06-01

    Venous thromboembolism (VTE) is rare in children and young adolescents, and occurs predominantly in those with congenital heart disease in whom guidelines exist for VTE prophylaxis. For other paediatric patients, the rarity of the event makes writing an evidence-based clinical practice guideline difficult because each of the known risk factors contributes only a small increase in risk. Thrombophilia screening is controversial because few results assist with prediction of likely thrombosis and may not alter recommendations for prophylaxis. Recent publications highlight the importance of non-pharmacological prevention of VTE in children and adolescents undergoing surgery and the importance of liaison among surgeon, anaesthetist and haematologist. This annotation was written with the aim of collating current evidence for VTE prophylaxis and emphasising the need for further research in vulnerable subgroups.

  10. Bilateral Pneumothoraces Following Central Venous Cannulation

    Science.gov (United States)

    Pazos, F.; Masterson, K.; Inan, C.; Robert, J.; Walder, B.

    2009-01-01

    We report the occurrence of a bilateral pneumothoraces after unilateral central venous catheterization of the right subclavian vein in a 70-year-old patient. The patient had no history of pulmonary or pleural disease and no history of cardiothoracic surgery. Two days earlier, she had a median laparotomy under general and epidural anaesthesia. Prior to the procedure, the patient was hemodynamically stable and her transcutaneous oxygen saturation was 97% in room air. We punctured the right pleural space before cannulation of the right subclavian vein. After the procedure, the patient slowly became hemodynamically instable with respiratory distress. A chest radiograph revealed a complete left-side pneumothorax and a mild right-side pneumothorax. The right-side pneumothorax became under tension after left chest tube insertion. The symptoms finally resolved after insertion of a right chest tube. After a diagnostic work-up, we suspect a congenital “Buffalo chests” explaining bilateral pneumothoraces and a secondary tension pneumothorax. PMID:19901997

  11. Venous thromboembolism prophylaxis in plastic surgery

    DEFF Research Database (Denmark)

    Nielsen, Lea Juul; Matzen, Steen H

    2017-01-01

    BACKGROUND: Venous thromboembolism is a well-documented complication of surgery, including plastic surgery. However, few consensus guidelines on thromboembolism prophylaxis exist in plastic surgery and, thus, the different approaches in the public as well as the private clinics in Denmark were...... investigated using a web-based survey. METHODS: Forty-two clinics were contacted and 45% responded. RESULTS: The collected data reveals a lack of consensus in plastic surgery in Denmark, not only regarding the use of mechanical and chemical prophylaxis, but also which type of prophylaxis to apply, the duration...... of prophylaxis, and how to risk stratify the patients. CONCLUSION: The development of a guideline, based on plastic surgical data, using a validated risk assessment model, which combines the surgical risk with the patient related risk and recommends guidelines for mechanical as well as chemoprophylaxis...

  12. [The diagnostic scores for deep venous thrombosis].

    Science.gov (United States)

    Junod, A

    2015-08-26

    Seven diagnostic scores for the deep venous thrombosis (DVT) of lower limbs are analyzed and compared. Two features make this exer- cise difficult: the problem of distal DVT and of their proximal extension and the status of patients, whether out- or in-patients. The most popular score is the Wells score (1997), modi- fied in 2003. It includes one subjective ele- ment based on clinical judgment. The Primary Care score 12005), less known, has similar pro- perties, but uses only objective data. The pre- sent trend is to associate clinical scores with the dosage of D-Dimers to rule out with a good sensitivity the probability of TVP. For the upper limb DVT, the Constans score (2008) is available, which can also be coupled with D-Dimers testing (Kleinjan).

  13. Systemic Venous Inflow to the Liver Allograft to Overcome Diffuse Splanchnic Venous Thrombosis

    Directory of Open Access Journals (Sweden)

    Cristian Lupascu

    2015-01-01

    Full Text Available Diffuse splanchnic venous thrombosis (DSVT, formerly defined as contraindication for liver transplantation (LT, is a serious challenge to the liver transplant surgeon. Portal vein arterialisation, cavoportal hemitransposition and renoportal anastomosis, and finally combined liver and small bowel transplantation are all possible alternatives to deal with this condition. Five patients with preoperatively confirmed extensive splanchnic venous thrombosis were transplanted using cavoportal hemitransposition (4x and renoportal anastomosis (1x. Median follow-up was 58 months (range: 0,5 to 130 months. Two patients with previous radiation-induced peritoneal injury died, respectively, 18 days and 2 months after transplantation. The three other patients had excellent long-term survival, despite the fact that two of them needed a surgical reintervention for severe gastrointestinal bleeding. Extensive splanchnic venous thrombosis is no longer an absolute contraindication to liver transplantation. Although cavoportal hemitransposition and renoportal anastomosis undoubtedly are life-saving procedures allowing for ensuring adequate allograft portal flow, careful follow-up of these patients remains necessary as both methods are unable to completely eliminate the complications of (segmental portal hypertension.

  14. Central venous stenosis among hemodialysis patients is often not associated with previous central venous catheters.

    Science.gov (United States)

    Kotoda, Atsushi; Akimoto, Tetsu; Kato, Maki; Kanazawa, Hidenori; Nakata, Manabu; Sugase, Taro; Ogura, Manabu; Ito, Chiharu; Sugimoto, Hideharu; Muto, Shigeaki; Kusano, Eiji

    2011-01-01

    It is widely assumed that central venous stenosis (CVS) is most commonly associated with previous central venous catheterization among the chronic hemodialysis (HD) patients. We evaluated the validity of this assumption in this retrospective study. The clinical records from 2,856 consecutive HD patients with vascular access failure during a 5-year period were reviewed, and a total of 26 patients with symptomatic CVS were identified. Combined with radiological findings, their clinical characteristics were examined. Only seven patients had a history of internal jugular dialysis catheterization. Diagnostic multidetector row computed tomography angiography showed that 7 of the 19 patients with no history of catheterization had left innominate vein stenosis due to extrinsic compression between the sternum and arch vessels. These patients had a shorter period from the time of creation of the vascular access to the initial referral (9.2 ± 7.6 months) than the rest of the patients (35.5 ± 18.6 months, p = 0.0017). Our findings suggest that cases without a history of central venous catheterization may not be rare among the HD patients with symptomatic CVS. However, those still need to be confirm by larger prospective studies of overall chronic HD patients with symptomatic CVS.

  15. Duplex correlation phlebography in venous mapping of the upper limbs for artery venous fistulas for hemodialysis

    International Nuclear Information System (INIS)

    Esperon Percovich, A.; Lopez Chapuis, D.; Velverdu, M.; Curi, J.; Sciuto, F.; Velverdu, M.; Curi, J.

    1995-01-01

    When clinical evaluation is not enough,the evaluation of the venous condition of the upper limbs for the realization of angio access for hemodialysis is classically based on phlebography,an invasive,risky method.the appear rance of non invasive techniques such as eco Doppler(duplex) makes it necessary to do research in order to determine the utility of the method and define its indications.The authors analyse 35 venous mappings of the upper limbs by phlebography and duplex and compare its results for the different venous regions.They come to the conclusion that duplex presented the best performance for the hum ero axillary subclavian region,detecting thrombosis with a sensitivity of 100% a specificity of 97% positive predictive value of 50% and negative predictive value of 100%.For superficial axis (radial and superficial ulnar,basilic and cephalic)there is low sensitivity for the determination of presence and permeability of the axis but 100% specificity.Duplex was not useful for the description of veins in order to determine utility for Avf.Finally,the authors make recommendations as regards indications of these para clinical tests [es

  16. The Role of Inflammation in Venous Thromboembolism

    Directory of Open Access Journals (Sweden)

    Brian R. Branchford

    2018-05-01

    Full Text Available Venous thromboembolism (VTE, comprising deep vein thrombosis (DVT, and pulmonary embolism (PE, is becoming increasingly recognized as a cause of morbidity and mortality in pediatrics, particularly among hospitalized children. Furthermore, evidence is accumulating that suggests the inflammatory response may be a cause, as well as consequence, of VTE, but current anticoagulation treatment regimens are not designed to inhibit inflammation. In fact, many established clinical VTE risk factors such as surgery, obesity, cystic fibrosis, sepsis, systemic infection, cancer, inflammatory bowel disease, and lupus likely modulate thrombosis through inflammatory mediators. Unlike other traumatic mechanisms of thrombosis involving vascular transection and subsequent exposure of subendothelial collagen and other procoagulant extracellular matrix materials, inflammation of the vessel wall may initiate thrombosis on an intact vein. Activation of endothelial cells, platelets, and leukocytes with subsequent formation of microparticles can trigger the coagulation system through the induction of tissue factor (TF. Identification of biomarkers to evaluate VTE risk could be of great use to the clinician caring for a patient with inflammatory disease to guide decisions regarding the risk:benefit ratio of various types of potential thromboprophylaxis strategies, or suggest a role for anti-inflammatory therapy. Unfortunately, no such validated inflammatory scoring system yet exists, though research in this area is ongoing. Elevation of C-reactive protein, IL-6, IL-8, and TNF-alpha during a response to systemic inflammation have been associated with increased VTE risk. Consequent platelet activation enhances the prothrombotic state, leading to VTE development, particularly in patients with other risk factors, most notably central venous catheters.

  17. [Association between venous thrombosis and dyslipidemia].

    Science.gov (United States)

    García Raso, Aránzazu; Ene, Gabriela; Miranda, Carolina; Vidal, Rosa; Mata, Raquel; Llamas Sillero, M Pilar

    2014-07-07

    Venous and arterial thrombosis, despite being historically considered as distinct conditions, share certain risk factors. Dyslipidemia is a clinical condition with a relatively high prevalence in the population and has been associated with an increased thrombotic risk. Lipids and lipoproteins modulate the expression and/or function of thrombotic, fibrinolytic and rheological factors. We have developed a descriptive, retrospective, comparative, cross-sectional study including a group of 313 patients with venous thromboembolism (VTE). We collected basic demographic data, cardiovascular risk factors and thrombotic complications. All patients were subjected to a lipid profile study with determination of total cholesterol, high density lipoprotein cholesterol (cHDL), low density lipoprotein cholesterol (cLDL) and triglycerides. The multivariable analysis showed that dyslipidemia was a risk factor for VTE (odds ratio [OR] 3.87, 95% confidence interval [95% CI] 2.72-5.56; P<.0001). Of a total of 313 patients included in the study, 31% (n=97) had a recurrent thrombotic event and 23% (n=72) developed post-thrombotic syndrome. cHDL levels below 35 mg/dl and cLDL levels higher than 180 mg/dl represented risk factors for the development of recurrent thrombosis, OR 3.12 (95% CI 1.35-7.74; P=.008) and OR 2.35 (95% CI 1.24-4.45; P=.008), respectively, and post-thrombotic syndrome, OR 3.44 (95% CI 1.43-8.83; P=.005) and OR 2.35 (95% CI 1.24-4.45; P=.008). Our study confirmed the association between dyslipidemia and VTE and showed a risk of thrombosis nearly 4 times higher in individuals with this disease. In addition, alterations in the lipid profile were also related to a higher prevalence of thrombotic complications, recurrence and post-thrombotic syndrome. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  18. Hepatic venous pressure gradients measured by duplex ultrasound

    International Nuclear Information System (INIS)

    Tasu, J.-P.; Rocher, L.; Peletier, G.; Kuoch, V.; Kulh, E.; Miquel, A.; Buffet, C.; Biery, M.

    2002-01-01

    AIMS: The hepatic venous pressure gradient is a major prognostic factor in portal hypertension but its measurement is complex and requires invasive angiography. This study investigated the relationship between the hepatic venous pressure gradient and a number of Doppler measurements, including the arterial acceleration index. METHOD: We measured the hepatic venous pressure gradient in 50 fasting patients at hepatic venography. Immediately afterwards, a duplex sonographic examination of the liver was performed at which multiple measurements and indices of the venous and arterial hepatic vasculature were made. RESULTS: Hepatic arterial acceleration was correlated directly with the hepatic venous pressure gradient (r = 0.83, P -2 provided a positive predictive value of 95%, a sensitivity of 65% and a specificity of 95% for detecting patients with severe portal hypertension (hepatic venous pressure gradient > 12 mmHg). A correlation between the hepatic venous pressure gradient and the congestion index of the portal vein velocity (r = 0.45,P = 0.01) and portal vein velocity (r = 0.40,P = 0.044), was also noted. CONCLUSION: Measuring the hepatic arterial acceleration index may help in the non-invasive evaluation of portal hypertension. Tasu, J.-P. et al. (2002)

  19. Venous anomalies and abnormalities of the posterior fossa

    International Nuclear Information System (INIS)

    Goulao, A.; Alvarez, H.; Garcia Monaco, R.; Pruvost, P.; Lasjaunias, P.

    1990-01-01

    The authors report a series of 16 patients with venous anomalies or abnormalities of the posterior fossa studied by angiography, CT and/or MRI. We believe that so-called 'venous angioma' are extreme anatomic variants that drain normal territories, and we prefer to call them developmental venous anomalies (DVA). Posterior fossa DVA, like the supra-tentorial ones are classified according to their drainage into deep and superficial type. They are exclusively located in the cerebellum or tectum. In 4 cases DVA was an incidental finding, in 3 an associated cerebral venous malformation (CVM) was found and felt to be the cause of the symptoms and only in one (Trigeminal pain) was a link between both suspected. Cavernous venous malformation (CVM) were found in frequent association with DVA (27%). 4 cases were single and 2 multiple. 5 CVM were located in the brain stem and 3 in the cerebellum. The clinical and radiological files were reviewed and a direct relationship between symptoms and localization was found in all patients with CVM. In 2 cases venous dysplasia was found: 1 Sturge-Weber and 1 First branchial arch syndrome. Both posterior fossa venous abnormalities were incidental findings. (orig.)

  20. Cardiovascular Pressures with Venous Gas Embolism and Decompression

    Science.gov (United States)

    Butler, B. D.; Robinson, R.; Sutton, T.; Kemper, G. B.

    1995-01-01

    Venous gas embolism (VGE) is reported with decompression to a decreased ambient pressure. With severe decompression, or in cases where an intracardiac septal defect (patent foramen ovale) exists, the venous bubbles can become arterialized and cause neurological decompression illness. Incidence rates of patent foramen ovale in the general population range from 25-34% and yet aviators, astronauts, and deepsea divers who have decompression-induced venous bubbles do not demonstrate neurological symptoms at these high rates. This apparent disparity may be attributable to the normal pressure gradient across the atria of the heart that must be reversed for there to be flow potency. We evaluated the effects of: venous gas embolism (0.025, 0.05 and 0.15 ml/ kg min for 180 min.) hyperbaric decompression; and hypobaric decompression on the pressure gradient across the left and right atria in anesthetized dogs with intact atrial septa. Left ventricular end-diastolic pressure was used as a measure of left atrial pressure. In a total of 92 experimental evaluations in 22 dogs, there were no reported reversals in the mean pressure gradient across the atria; a total of 3 transient reversals occurred during the peak pressure gradient changes. The reasons that decompression-induced venous bubbles do not consistently cause serious symptoms of decompression illness may be that the amount of venous gas does not always cause sufficient pressure reversal across a patent foramen ovale to cause arterialization of the venous bubbles.

  1. Postoperative deep venous thrombosis in Japan. Incidence and prophylaxis

    International Nuclear Information System (INIS)

    Inada, K.; Shirai, N.; Hayashi, M.; Matsumoto, K.; Hirose, M.

    1983-01-01

    The incidence of postoperative deep venous thrombosis was investigated using the iodine-125-fibrinogen method in 256 patients undergoing major surgery. Deep venous thrombosis was found in 49 patients (15.3 percent), and nonfatal pulmonary embolism developed in one of seven patients in whom the thrombus extended to the popliteal vein. The same investigation was performed in 110 patients who wore a graduated compression stocking on one leg, with the other leg serving as a control. Deep venous thrombosis was found in 4 of 110 stockinged legs (3.6 percent) and in 16 of 110 control legs (14.5 percent). The incidence of deep venous thrombosis decreased significantly in patients who wore the stocking. An increase in femoral venous flow velocity was found in the stockinged legs by the Doppler method. The mean velocity of venous return by xenon-133 clearance was significantly greater in the stockinged legs than in the control legs. These findings were considered to support the efficacy of graduated compression stockings for the prevention of deep venous thrombosis

  2. Hepatic venous pressure gradients measured by duplex ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Tasu, J.-P.; Rocher, L.; Peletier, G.; Kuoch, V.; Kulh, E.; Miquel, A.; Buffet, C.; Biery, M

    2002-08-01

    AIMS: The hepatic venous pressure gradient is a major prognostic factor in portal hypertension but its measurement is complex and requires invasive angiography. This study investigated the relationship between the hepatic venous pressure gradient and a number of Doppler measurements, including the arterial acceleration index. METHOD: We measured the hepatic venous pressure gradient in 50 fasting patients at hepatic venography. Immediately afterwards, a duplex sonographic examination of the liver was performed at which multiple measurements and indices of the venous and arterial hepatic vasculature were made. RESULTS: Hepatic arterial acceleration was correlated directly with the hepatic venous pressure gradient (r = 0.83, P < 0.0001) and with the Child-Pugh score (r = 0.63, P < 0.0001). An acceleration index cut-off value of 1 m.s{sup -2} provided a positive predictive value of 95%, a sensitivity of 65% and a specificity of 95% for detecting patients with severe portal hypertension (hepatic venous pressure gradient > 12 mmHg). A correlation between the hepatic venous pressure gradient and the congestion index of the portal vein velocity (r = 0.45,P = 0.01) and portal vein velocity (r = 0.40,P = 0.044), was also noted. CONCLUSION: Measuring the hepatic arterial acceleration index may help in the non-invasive evaluation of portal hypertension. Tasu, J.-P. et al. (2002)

  3. Circular waveguide mode converters at 140 GHz

    International Nuclear Information System (INIS)

    Trulsen, J.; Woskoboinikow, P.; Temkin, R.J.

    1986-01-01

    A unified derivation of the coupled mode equations for circular waveguide is presented. Also, approximate design criteria for TE/sub 0n/ to TE/sub 0n'/ axisymmetric, TE 01 to TE 11 wriggle, and TE 01 to TM 11 bend converters are reviewed. Numerically solving the coupled mode equations, an optimized set of mode converters has been designed for conversion of a 2 millimeter wave TE 03 mode into TE 11 . This set consists of axisymmetric TE 03 to TE 02 and TE 02 to TE 01 converters followed by a wriggle TE 01 to TE 11 converter. This mode converter set was fabricated and tested using a 3 kW, 137 GHz gyrotron. A TE 11 mode purity of better than 97% was achieved. The TE 01 to TE 11 wriggle converter was experimentally optimized for a measured conversion efficiency of better than 99% not including ohmic losses

  4. Venous and Arterial Thromboses: Two Sides of the Same Coin?

    Science.gov (United States)

    Lippi, Giuseppe; Favaloro, Emmanuel J

    2018-04-01

    Arterial and venous thromboses are sustained by development of intraluminal thrombi, respectively, within the venous and arterial systems. The composition and structure of arterial and venous thrombi have been historically considered as being very different. Arterial thrombi (conventionally defined as "white") have been traditionally proposed to be composed mainly of fibrin and platelet aggregates, whilst venous thrombi (conventionally defined as "red") have been proposed as mostly being enriched in fibrin and erythrocytes. This archaic dichotomy seems ever more questionable, since it barely reflects the pathophysiology of thrombus formation in vivo. Both types of thrombi are actually composed of a complex fibrin network but, importantly, also contain essentially the same blood-borne cells (i.e., red blood cells, leukocytes, and platelets), and it is only the relative content of these individual elements that differ between venous and arterial clots or, otherwise, between thrombi generated under different conditions of blood flow and shear stress. Convincing evidence now suggests that either white or red intracoronary thrombi may be present in patients with myocardial infarction and, even more importantly, red thrombi may be more prone to distal embolization during percutaneous coronary intervention than those with lower content of erythrocytes. Conversely, it is now accepted that components traditionally considered to be involved "only" in arterial thrombosis are also represented in venous thrombosis. Thus, platelets comprise important components of venous clots, although they may be present in lower amounts here than in arterial thrombi, and von Willebrand factor is also represented in both arterial and venous thrombi. Of importance, such evidence thus supports the concept that adjunctive treatment normally associated to prevention of arterial thrombosis (e.g., aspirin) may have a role also in prevention and treatment of venous thrombosis. Thieme Medical

  5. ENDOVASCULAR TREATMENT FOR DISORDERS OF THE VENOUS SYSTEM

    Directory of Open Access Journals (Sweden)

    A. G. Osiev

    2015-01-01

    Full Text Available The annual rate of deep vein thrombosis in general population is from 5 to 9 cases per 10 000, whereas for venous thromboembolism (deep vein thrombosis and pulmonary embolism taken together amounts to 14 cases per 10 000. To improve longterm results of therapy for thrombosis of deep veins of the lower extremities, it is important to restore venous function and outflow. Anticoagulant therapy with low weight or non-fractionated heparin preparations remains the most widely used method of management. However, total or partial thrombosis resolution under anticoagulant treatment is achieved only in 4 and 14% of cases, respectively. Thrombolysis allows for early resorption of the thrombus by means of a minimally invasive procedure with lower risk of complication. After the venous flow is restored, the aim of treatment is to prevent damage to the venous valves, venous hypertension and repeated thrombosis with development of the post-thrombotic syndrome. Compared to anticoagulation, systemic thrombolysis has the benefit of more rapid clot resorption and less damage to the venous valve. One of its serious limitations is a high bleeding risk related to higher doses of the drug administered through a peripheral vein catheter. Therefore, selective intra-clot administration of thombolytics (direct catheter thrombolysis has been suggested as an alternative. For more effective therapy with the use of lower doses of thrombolytics, the so called pharmaco-mechanical thrombectomy has been developed. Venous stenosis hindering the venous outflow is frequently seen after direct catheter or pharmaco-mechanical thrombolysis. Angioplasty with stent placement is recommended in the cases with residual venous abnormality after successful thrombolysis and thrombectomy. 

  6. Efeito do tempo após a ingestão de leite sobre o equilíbrio ácido-básico de bezerros Effect of the time after milk feeding on the acid-base balance of calves

    Directory of Open Access Journals (Sweden)

    J.A.N. Lisbôa

    2003-12-01

    Full Text Available Blood pH, carbon dioxide and oxygen partial pressures, bicarbonate, total carbon dioxide, base excess, standard bicarbonate and oxygen saturation concentrations were measured by blood gas analyses in a study of assessment of the acid-base status in young calves. Venous blood samples were taken from 80 healthy female Holstein calves, from four to 30 days of age. The calves were divided in two groups based on the interval between the morning milk feeding and the blood sample collection (up to 30 minutes or over two hours. Greater alkali reserve and higher carbon dioxide pressure values were observed later than 2h after milk feeding, supporting the influence of the diet on the acid-base balance of calves during the milk feeding phase.

  7. Ocean floor mounting of wave energy converters

    Science.gov (United States)

    Siegel, Stefan G

    2015-01-20

    A system for mounting a set of wave energy converters in the ocean includes a pole attached to a floor of an ocean and a slider mounted on the pole in a manner that permits the slider to move vertically along the pole and rotate about the pole. The wave energy converters can then be mounted on the slider to allow adjustment of the depth and orientation of the wave energy converters.

  8. Vacuum-insulated catalytic converter

    Science.gov (United States)

    Benson, David K.

    2001-01-01

    A catalytic converter has an inner canister that contains catalyst-coated substrates and an outer canister that encloses an annular, variable vacuum insulation chamber surrounding the inner canister. An annular tank containing phase-change material for heat storage and release is positioned in the variable vacuum insulation chamber a distance spaced part from the inner canister. A reversible hydrogen getter in the variable vacuum insulation chamber, preferably on a surface of the heat storage tank, releases hydrogen into the variable vacuum insulation chamber to conduct heat when the phase-change material is hot and absorbs the hydrogen to limit heat transfer to radiation when the phase-change material is cool. A porous zeolite trap in the inner canister absorbs and retains hydrocarbons from the exhaust gases when the catalyst-coated substrates and zeolite trap are cold and releases the hydrocarbons for reaction on the catalyst-coated substrate when the zeolite trap and catalyst-coated substrate get hot.

  9. The determination of acid-base properties of polymer surfaces by XPS: Present status and future prospects

    International Nuclear Information System (INIS)

    Chehimi, M.M.; Delamar, M.; Shahidzadeh-Ahmadi, N.; Arefi-Khonsari, F.; Amouroux, J.; Watts, J.F.

    1996-01-01

    The use of the molecular probe technique in conjunction with X-ray photoelectron spectroscopy (XPS) for the assessment of acid-base properties of polymer surfaces is reviewed. The method is based on the determination of the concentration and chemical shifts of Lewis acids (bases) sorbed in polymers of basic (acidic) character. In the case of chloroform (Lewis acid) sorbed in polymers of Lewis basic character, C12p binding energy is linearly correlated with ΔH AB , the heat of acid-base complex formation chloroform-polymer. This relationship has been used to determine the acid-base properties of poly(phenylene oxide), a homopolymer, and ammonia plasma-treated polypropylene. This work shows that XPS can now indeed be used to quantitatively assess the acid-base properties of modified polymer surfaces and perhaps be extended to map acid-base properties of polymer surfaces at the micron or submicron scale. copyright 1996 American Institute of Physics

  10. Semi-automatic logarithmic converter of logs

    International Nuclear Information System (INIS)

    Gol'dman, Z.A.; Bondar's, V.V.

    1974-01-01

    Semi-automatic logarithmic converter of logging charts. An original semi-automatic converter was developed for use in converting BK resistance logging charts and the time interval, ΔT, of acoustic logs from a linear to a logarithmic scale with a specific ratio for subsequent combining of them with neutron-gamma logging charts in operative interpretation of logging materials by a normalization method. The converter can be used to increase productivity by giving curves different from those obtained in manual, pointwise processing. The equipment operates reliably and is simple in use. (author)

  11. Multilevel converters for 10 MW Wind Turbines

    DEFF Research Database (Denmark)

    Ma, Ke; Blaabjerg, Frede

    2011-01-01

    Several promising multi-level converter configurations for 10 MW Wind Turbines both with direct drive and one-stage gear box drive using Permanent Magnet Synchronous Generator (PMSG) are proposed, designed and compared. Reliability is a crucial indicator for large scale wind power converters...... that the three-level and five-level H-bridge converter topologies both have potential to achieve improved thermal performances compared to the three-level Neutral-Point-Clamped converter topology in the wind power application....

  12. Commutation Processes in Multiresonant ZVS Bridge Converter

    Directory of Open Access Journals (Sweden)

    Miroslaw Luft

    2008-01-01

    Full Text Available The analysis of the multiresonant ZVS DC/DC bridge converter is presented. The control system of the converter is basedon the method of frequency control at the constant time of transistor turn-off with a phase shift. The operation of the circuit is givenand the operating range of the converter is defined where ZVS switching operation is assured. Control characteristics are given andthe converter’s efficiency is defined. The circuit’s operation is analysed on the basis of results of the converter simulation tests using Simplorer programme.

  13. Hypodense bubbles in acute extradural haematomas following venous sinus tear

    International Nuclear Information System (INIS)

    Chee, C.P.; Habib, Z.A.

    1991-01-01

    Between January 1982 and December 1989, 12 patients with 13 acute extradural haematomas as a result of injury involving the venous sinuses were treated by the first author. The CT scan apperances in 6 cases were remarkable in that there were large bubbles of low density in the hyperdense haematomas and liquid blood was found during the operation. The possible underlying pathophysiological changes that gave rise this appearance are discussed. The CT scan appearance and the proximity of the clot to the venous sinuses should alert the neurosurgeon to the high probabilities of venous sinus tear such that proper treatment can be offered. (orig.)

  14. Hypodense bubbles in acute extradural haematomas following venous sinus tear

    Energy Technology Data Exchange (ETDEWEB)

    Chee, C.P.; Habib, Z.A. (Malaya Univ. Hospital, Kuala Lumpur (Malaysia). Neurosurgical and Radiological Services)

    1991-04-01

    Between January 1982 and December 1989, 12 patients with 13 acute extradural haematomas as a result of injury involving the venous sinuses were treated by the first author. The CT scan apperances in 6 cases were remarkable in that there were large bubbles of low density in the hyperdense haematomas and liquid blood was found during the operation. The possible underlying pathophysiological changes that gave rise this appearance are discussed. The CT scan appearance and the proximity of the clot to the venous sinuses should alert the neurosurgeon to the high probabilities of venous sinus tear such that proper treatment can be offered. (orig.).

  15. Traumatic dural venous sinus thrombosis: A Mini Review

    Directory of Open Access Journals (Sweden)

    Moscote-Salazar Luis Rafael

    2016-09-01

    Full Text Available The dural venous sinus thrombosis is a benign disease, representing about 1% of cerebral vascular events. In some cases the development of the disease increased intracranial pressure or symptomatic epilepsy. The development towards a dural venous sinus thrombosis is rare, but is a condition to be considered before the development of ischemic vascular events and a history of recent head trauma. Intracranial hematomas or skull fractures can lead to the establishment of obstructive pathology of the dural venous sinuses. The knowledge of this entity is necessary for the critical care staff and neurosurgery staff.

  16. Acute Mesenteric Venous Thrombosis with a Vaginal Contraceptive Ring

    Directory of Open Access Journals (Sweden)

    Wesley Eilbert

    2014-07-01

    Full Text Available Mesenteric venous thrombosis is a rare cause of abdominal pain, which if left untreated may result in bowel infarction, peritonitis and death. The majority of patients with this illness have a recognizable, predisposing prothrombotic condition. Oral contraceptives have been identified as a predisposing factor for mesenteric venous thrombosis in reproductive-aged women. In the last fifteen years new methods of hormonal birth control have been introduced, including a transdermal patch and an intravaginal ring. In this report, we describe a case of mesenteric venous thrombosis in a young woman caused by a vaginal contraceptive ring. [West J Emerg Med. 2014;15(4:395-397.

  17. Arterial versus venous lactate: a measure of sepsis in children.

    Science.gov (United States)

    Samaraweera, Sahan Asela; Gibbons, Berwyck; Gour, Anami; Sedgwick, Philip

    2017-08-01

    This study assessed the agreement between arterial and venous blood lactate and pH levels in children with sepsis. This retrospective, three-year study involved 60 PICU patients, with data collected from electronic or paper patient records. The inclusion criteria comprised of children (≤17 years old) with sepsis and those who had a venous blood gas taken first with an arterial blood gas taken after within one hour. The lactate and pH values measured through each method were analysed. There is close agreement between venous and arterial lactate up to 2 mmol/L. As this value increases, this agreement becomes poor. The limits of agreement (LOA) are too large (±1.90 mmol/L) to allow venous and arterial lactate to be used interchangeably. The mean difference and LOA between both methods would be much smaller if derived using lactate values under 2.0 mmol/L. There is close agreement between arterial and venous pH (MD = -0.056, LOA ± 0.121). However, due to extreme variations in pH readings during sepsis, pH alone is an inadequate marker. A venous lactate ≤2 mmol/L can be used as a surrogate for arterial lactate during early management of sepsis in children. However, if the value exceeds 2 mmol/L, an arterial sample must confirm the venous result. What is known: • In children with septic shock, a blood gas is an important test to show the presence of acidosis and high lactic acid. Hyperlactataemia on admission is an early predictor of outcome and is associated with a greater mortality risk. • An arterial sample is the standard for lactate measurement, however getting a sample may be challenging in the emergency department or a general paediatric ward. Venous samples are quicker and easier to obtain. Adult studies generally advise caution in replacing venous lactate values for the arterial standard, whilst paediatric studies are limited in this area. What is new: • This is the first study assessing the agreement between arterial and peripheral venous

  18. Re-Evaluation of Acid-Base Prediction Rules in Patients with Chronic Respiratory Acidosis

    Directory of Open Access Journals (Sweden)

    Tereza Martinu

    2003-01-01

    Full Text Available RATIONALE: The prediction rules for the evaluation of the acid-base status in patients with chronic respiratory acidosis, derived primarily from an experimental canine model, suggest that complete compensation should not occur. This appears to contradict frequent observations of normal or near-normal pH levels in patients with chronic hypercapnia.

  19. The Effect of Voluntary Ventilation on Acid-base Responses to a Moo Duk Tkow Form.

    Science.gov (United States)

    Hetzler, Ronald K.; And Others

    1989-01-01

    Results are reported from a study that investigated the acid-base and lactate reponses to voluntary integration of breathing and exercise movements during beginning level form Ki Cho I, performed at competitive intensities. Findings suggest that respiratory compensation does not occur and that respiratory acidosis may contribute to metabolic…

  20. Intracellular pH regulation by acid-base transporters in mammalian neurons

    Science.gov (United States)

    Ruffin, Vernon A.; Salameh, Ahlam I.; Boron, Walter F.; Parker, Mark D.

    2014-01-01

    Intracellular pH (pHi) regulation in the brain is important in both physiological and physiopathological conditions because changes in pHi generally result in altered neuronal excitability. In this review, we will cover 4 major areas: (1) The effect of pHi on cellular processes in the brain, including channel activity and neuronal excitability. (2) pHi homeostasis and how it is determined by the balance between rates of acid loading (JL) and extrusion (JE). The balance between JE and JL determine steady-state pHi, as well as the ability of the cell to defend pHi in the face of extracellular acid-base disturbances (e.g., metabolic acidosis). (3) The properties and importance of members of the SLC4 and SLC9 families of acid-base transporters expressed in the brain that contribute to JL (namely the Cl-HCO3 exchanger AE3) and JE (the Na-H exchangers NHE1, NHE3, and NHE5 as well as the Na+- coupled HCO3− transporters NBCe1, NBCn1, NDCBE, and NBCn2). (4) The effect of acid-base disturbances on neuronal function and the roles of acid-base transporters in defending neuronal pHi under physiopathologic conditions. PMID:24592239

  1. Approach to acid-base disorders – a clinical chemistry perspective

    African Journals Online (AJOL)

    Table 1. Simple acid-base disorders. Disorder. pH. pCO2. HCO3. -. Clinical examples. Respiratory acidosis ... Lactic acidosis or diabetic ketoacidosis and vomiting. Triple disorder: .... Renal tubular acidosis type 1 and 2. Ureteral diversion to ...

  2. Soluble adenylyl cyclase is an acid-base sensor in epithelial base-secreting cells.

    Science.gov (United States)

    Roa, Jinae N; Tresguerres, Martin

    2016-08-01

    Blood acid-base regulation by specialized epithelia, such as gills and kidney, requires the ability to sense blood acid-base status. Here, we developed primary cultures of ray (Urolophus halleri) gill cells to study mechanisms for acid-base sensing without the interference of whole animal hormonal regulation. Ray gills have abundant base-secreting cells, identified by their noticeable expression of vacuolar-type H(+)-ATPase (VHA), and also express the evolutionarily conserved acid-base sensor soluble adenylyl cyclase (sAC). Exposure of cultured cells to extracellular alkalosis (pH 8.0, 40 mM HCO3 (-)) triggered VHA translocation to the cell membrane, similar to previous reports in live animals experiencing blood alkalosis. VHA translocation was dependent on sAC, as it was blocked by the sAC-specific inhibitor KH7. Ray gill base-secreting cells also express transmembrane adenylyl cyclases (tmACs); however, tmAC inhibition by 2',5'-dideoxyadenosine did not prevent alkalosis-dependent VHA translocation, and tmAC activation by forskolin reduced the abundance of VHA at the cell membrane. This study demonstrates that sAC is a necessary and sufficient sensor of extracellular alkalosis in ray gill base-secreting cells. In addition, this study indicates that different sources of cAMP differentially modulate cell biology. Copyright © 2016 the American Physiological Society.

  3. Characterization of Brønsted acid-base complexes by ¹⁹F DOSY.

    Science.gov (United States)

    Subramanian, Hariharaputhiran; Jasperse, Craig P; Sibi, Mukund P

    2015-03-20

    A (19)F DOSY protocol for the determination of formula weights for acid-base complexes in solution has been developed. (19)F internal standards were chosen and were used to evaluate the formula weights of complexes in solution using simple diffusion coefficient (D)-formula weight (FW) analysis. This method has potential applications in characterization of reactive intermediates in catalytic asymmetric reactions.

  4. Evaluation of the number of ionogenic groups of inulinase by acid-base titration.

    Science.gov (United States)

    Kovaleva, T A; Holyavka, M G; Rezvan, S G; Kozhedub, S V

    2008-06-01

    Acid base titration showed that Aspergillus awamori inulinase includes 178 asparaginic and glutamic acid residues, 20 histidine, 10 serine, and 34 lysine and tyrosine residues. Denaturation temperature for this enzyme was calculated using analysis of the proportion of stabilizing and destabilizing amino acids in the molecule.

  5. Acid-base titration curves in an integrated computer learning environment

    NARCIS (Netherlands)

    Heck, A.; Kędzierska, E.; Rodgers, L.; Chmurska, M.

    2008-01-01

    The topic of acid-base reactions is a regular component of many chemistry curricula that requires integrated understanding of various areas of introductory chemistry. Many students have considerable difficulties understanding the concepts and processes involved. It has been suggested and confirmed

  6. Determining surface areas of marine alga cells by acid-base titration method.

    Science.gov (United States)

    Wang, X; Ma, Y; Su, Y

    1997-09-01

    A new method for determining the surface area of living marine alga cells was described. The method uses acid-base titration to measure the surface acid/base amount on the surface of alga cells and uses the BET (Brunauer, Emmett, and Teller) equation to estimate the maximum surface acid/base amount, assuming that hydrous cell walls have carbohydrates or other structural compounds which can behave like surface Brönsted acid-base sites due to coordination of environmental H2O molecules. The method was applied to 18 diverse alga species (including 7 diatoms, 2 flagellates, 8 green algae and 1 red alga) maintained in seawater cultures. For the species examined, the surface areas of individual cells ranged from 2.8 x 10(-8) m2 for Nannochloropsis oculata to 690 x 10(-8) m2 for Dunaliella viridis, specific surface areas from 1,030 m2.g-1 for Dunaliella salina to 28,900 m2.g-1 for Pyramidomonas sp. Measurement accuracy was 15.2%. Preliminary studies show that the method may be more promising and accurate than light/electron microscopic measurements for coarse estimation of the surface area of living algae.

  7. The Acid-Base Titration of a Very Weak Acid: Boric Acid

    Science.gov (United States)

    Celeste, M.; Azevedo, C.; Cavaleiro, Ana M. V.

    2012-01-01

    A laboratory experiment based on the titration of boric acid with strong base in the presence of d-mannitol is described. Boric acid is a very weak acid and direct titration with NaOH is not possible. An auxiliary reagent that contributes to the release of protons in a known stoichiometry facilitates the acid-base titration. Students obtain the…

  8. The incidence of electrolyte and acid-base abnormalities in critically ...

    African Journals Online (AJOL)

    Background: Electrolytes and acid-base disorders are common challenges seen in the intensive care unit (ICU) resulting in difficulty in weaning patients off the ventilator, prolonged admission periods, preventable cardiac arrhythmias and cardiac arrest. These require prompt lab results most of which are done serially, ...

  9. Maternal and Fetal Acid-Base Chemistry: A Major Determinant of ...

    African Journals Online (AJOL)

    Very small changes in pH may significantly affect the function of various fetal organ systems, such as the central nervous system, and the cardiovascular system with associated fetal distress and poor Apgar score. Review of existing data on maternal-fetal acid-base balance in pregnancy highlight the factors that are ...

  10. Lewis Acid-Base Properties of a Low Carbon Aluminium Killed Steel ...

    African Journals Online (AJOL)

    An important factor in achieving maximum adhesion of a particular coating system to the substrate lies in the proper preparation of the substrate prior to the application of paint. The Lewis acid-base properties of the outer metal surface play a determinant role in many of these applications, and the chemical reactions involved ...

  11. Nutrient intake, acid base status and weight gain in water buffalo ...

    African Journals Online (AJOL)

    The impact of different dietary levels of sodium bicarbonate (NaHCO3) on nutrient intake, acid-base status, nitrogen balance and weight gain was examined in growing male buffalo (Bubalus bubalis) calves exposed to hot summer conditions. In a complete randomized block design 60 animals of similar age and weight ...

  12. 78 FR 36698 - Microbiology Devices; Reclassification of Nucleic Acid-Based Systems for Mycobacterium tuberculosis

    Science.gov (United States)

    2013-06-19

    .... FDA-2013-N-0544] Microbiology Devices; Reclassification of Nucleic Acid-Based Systems for... workshop, FDA agreed to consider this issue further and subsequently convened a meeting of the Microbiology... Health After considering the information discussed by the Microbiology Devices Panel during the June 29...

  13. 77 FR 16126 - Microbiology Devices; Reclassification of Nucleic Acid-Based Systems for Mycobacterium tuberculosis

    Science.gov (United States)

    2012-03-19

    .... FDA-2012-N-0159] Microbiology Devices; Reclassification of Nucleic Acid-Based Systems for... convened a meeting of the Microbiology Devices Panel of the Medical Devices Advisory Committee (Microbiology Devices Panel) on June 29, 2011 (Ref. 2). Although not a formal reclassification meeting, panel...

  14. Isoelectric Point, Electric Charge, and Nomenclature of the Acid-Base Residues of Proteins

    Science.gov (United States)

    Maldonado, Andres A.; Ribeiro, Joao M.; Sillero, Antonio

    2010-01-01

    The main object of this work is to present the pedagogical usefulness of the theoretical methods, developed in this laboratory, for the determination of the isoelectric point (pI) and the net electric charge of proteins together with some comments on the naming of the acid-base residues of proteins. (Contains 8 figures and 4 tables.)

  15. Stereoselective assembly of amino acid-based metal-biomolecule nanofibers.

    Science.gov (United States)

    Wu, Hong; Tian, Chunyong; Zhang, Yufei; Yang, Chen; Zhang, Songping; Jiang, Zhongyi

    2015-04-14

    A series of amino acid-based metal-biomolecule nanofibers are fabricated through a coordination-directed assembly process. The chirality and carbon chain length of the amino acids exert a pronounced influence on the assembly process. This study may be extended to design diverse kinds of 1-D metal-biomolecule frameworks (MBioFs).

  16. Effect of acute metabolic acid/base shifts on the human airway calibre.

    NARCIS (Netherlands)

    Brijker, F.; Elshout, F.J.J. van den; Heijdra, Y.F.; Bosch, F.H.; Folgering, H.T.M.

    2001-01-01

    Acute metabolic alkalosis (NaHCO(3)), acidosis (NH(4)Cl), and placebo (NaCl) were induced in 15 healthy volunteers (12 females, median age 34 (range 24-56) years) in a double blind, placebo controlled study to evaluate the presence of the effects on airway calibre. Acid-base shifts were determined

  17. Acid-base indicator properties of dyes from local plants I: Dyes from ...

    African Journals Online (AJOL)

    DR. MIKE HORSFALL

    Acid-base indicator properties of dyes from local plants I: Dyes from Basella alba. (Indian spinach) and ... solution, which change colour immediately after the equivalence point has .... The pH ranges over which the dyes change colour were ...

  18. Interactive Computer-Assisted Instruction in Acid-Base Physiology for Mobile Computer Platforms

    Science.gov (United States)

    Longmuir, Kenneth J.

    2014-01-01

    In this project, the traditional lecture hall presentation of acid-base physiology in the first-year medical school curriculum was replaced by interactive, computer-assisted instruction designed primarily for the iPad and other mobile computer platforms. Three learning modules were developed, each with ~20 screens of information, on the subjects…

  19. 'Chronic cerebrospinal venous insufficiency' in multiple sclerosis. Is multiple sclerosis a disease of the cerebrospinal venous outflow system?

    International Nuclear Information System (INIS)

    Wattjes, M.P.; Doepp, F.; Bendszus, M.; Fiehler, J.

    2011-01-01

    Chronic impaired venous outflow from the central nervous system has recently been claimed to be associated with multiple sclerosis (MS) pathology. This resulted in the term chronic cerebrospinal venous insufficiency (CCSVI) in MS. The concept of CCSVI is based on sonography studies showing that impaired venous outflow leading to pathological reflux is almost exclusively present in MS patients but not in healthy controls. Based on these findings, a new pathophysiological concept has been introduced suggesting that chronic venous outflow obstruction and venous reflux in the CNS result in pathological iron depositions leading to inflammation and neurodegeneration. The theory of CCSVI in MS has rapidly generated tremendous interest in the media and among patients and the scientific community. In particular, the potential shift in treatment concepts possibly leading to an interventional treatment approach including balloon angioplasty and venous stent placement is currently being debated. However, results from recent studies involving several imaging modalities have raised substantial concerns regarding the CCSVI concept in MS. In this review article, we explain the concept of CCSVI in MS and discuss this hypothesis in the context of MS pathophysiology and imaging studies which have tried to reproduce or refute this theory. In addition, we draw some major conclusions focusing in particular on the crucial question as to whether interventional treatment options are expedient. In conclusion, the present conclusive data confuting the theory of CCSVI in MS should lead to reluctance with respect to the interventional treatment of possible venous anomalies in MS patients. (orig.)

  20. Protocol for the realization of venous mapping by chronic venous insufficiency in lower limbs under sonographic guide

    International Nuclear Information System (INIS)

    Blanco Rojas, Diego Jose

    2013-01-01

    The current state of knowledge is reviewed with respect to the realization of lower limbs venous mapping. Venous mapping is obtained by the use of color and spectral Doppler ultrasound. Doppler ultrasound has provided a precise graphical representation of the superficial and deep venous systems. The performance of the venous mapping is considered essential for the correct handling of venous diseases. The anatomical and pathophysiological basic concepts are defined to realize the sonographic assessment of the veins of the lower limbs. The required technical aspects are revised for the realization of sonographic exploration of the patient with venous insufficiency. Sonographic findings are characterized to support the diagnostic of venous insufficiency of the lower limbs. The CEAP (clinical-etiologic-anatomic-pathophysiologic) classification is utilized to differentiate forms and degrees of severity of the disorder, and has allowed an interinstitutional comparison in clinical studies, the evaluation of treatment and monitoring of patients. A proposal is designed to perform reports that have served of guide surgical to vascular surgeons [es

  1. [Development and practice evaluation of blood acid-base imbalance analysis software].

    Science.gov (United States)

    Chen, Bo; Huang, Haiying; Zhou, Qiang; Peng, Shan; Jia, Hongyu; Ji, Tianxing

    2014-11-01

    To develop a blood gas, acid-base imbalance analysis computer software to diagnose systematically, rapidly, accurately and automatically determine acid-base imbalance type, and evaluate the clinical application. Using VBA programming language, a computer aided diagnostic software for the judgment of acid-base balance was developed. The clinical data of 220 patients admitted to the Second Affiliated Hospital of Guangzhou Medical University were retrospectively analyzed. The arterial blood gas [pH value, HCO(3)(-), arterial partial pressure of carbon dioxide (PaCO₂)] and electrolytes included data (Na⁺ and Cl⁻) were collected. Data were entered into the software for acid-base imbalances judgment. At the same time the data generation was calculated manually by H-H compensation formula for determining the type of acid-base imbalance. The consistency of judgment results from software and manual calculation was evaluated, and the judgment time of two methods was compared. The clinical diagnosis of the types of acid-base imbalance for the 220 patients: 65 cases were normal, 90 cases with simple type, mixed type in 41 cases, and triplex type in 24 cases. The accuracy of the judgment results of the normal and triplex types from computer software compared with which were calculated manually was 100%, the accuracy of the simple type judgment was 98.9% and 78.0% for the mixed type, and the total accuracy was 95.5%. The Kappa value of judgment result from software and manual judgment was 0.935, P=0.000. It was demonstrated that the consistency was very good. The time for software to determine acid-base imbalances was significantly shorter than the manual judgment (seconds:18.14 ± 3.80 vs. 43.79 ± 23.86, t=7.466, P=0.000), so the method of software was much faster than the manual method. Software judgment can replace manual judgment with the characteristics of rapid, accurate and convenient, can improve work efficiency and quality of clinical doctors and has great

  2. Partial anomalous pulmonary venous return in patients with pulmonary hypertension

    International Nuclear Information System (INIS)

    Sung, Won-kyung; Au, Virginia; Rose, Anand

    2012-01-01

    Anomalous pulmonary venous return is an uncommon congenital malformation, and may be partial or total. Partial anomalous pulmonary venous return (PAPVR) is more common than total anomalous pulmonary venous return, and is often associated with other congenital cardiac anomalies. Whilst many patients with PAPVR remain asymptomatic, some may present in later age with symptoms related to left-to-right shunt, right heart failure and pulmonary hypertension. We report two cases of PAPVR detected on Computed Tomography Pulmonary Angiogram (CTPA) for the work up of pulmonary hypertension. The cases demonstrate that, although uncommon, partial anomalous pulmonary venous return can be a contributing factor to pulmonary hypertension and pulmonary veins should be carefully examined when reading a CTPA study.

  3. Complication of Hemodialysis Access: A Case Report of Venous Hypertension

    Directory of Open Access Journals (Sweden)

    Sadegh Asadi

    2018-03-01

    Full Text Available Vascular access for dialysis is essential for these patients with end-stage renal disease, improvements in hemodialysis managment have lead to extended life expectancy. The creation and maintenance of hemoaccess occupies a significant portion of most vascular and general surgery practices.Venous hypertension due to arteriovenous fistula is usually secondary to venous outlet obstruction. Side to side proximal artery arteriovenous fistula serves as a certain cause of hemodialysis, but it is rarely reported as a peripheral venous hypertension cause. We are reporting a case with developed venous hypertension having dermal injuries in the arm. The patient underwent successful side-to-side radio cephalic fistula creation in the snuffbox a year ago.

  4. Splanchnic venous thrombosis driven by a constitutively activated ...

    African Journals Online (AJOL)

    Introduction: Splanchnic venous thrombosis (SVT) has varied etiology with Philadelphia-negative myeloproliferative neoplasms (MPNs) being the most frequent underlying prothrombotic factor. Hematological indices often remain within normal range because of portal hypertension and its sequelae, causing diagnostic ...

  5. Deep venous thrombosis and postthrombotic syndrome: invasive management.

    Science.gov (United States)

    Comerota, A J

    2015-03-01

    Invasive management of postthrombotic syndrome encompasses the two ends of the deep vein thrombosis spectrum, patients with acute iliofemoral deep vein thrombosis and those with chronic postthrombotic iliofemoral venous obstruction. Of all patients with acute deep vein thrombosis, those with involvement of the iliofemoral segments have the most severe chronic postthrombotic morbidity. Catheter-based techniques now permit percutaneous treatment to eliminate thrombus, restore patency, potentially maintain valvular function, and improve quality of life. Randomized trial data support an initial treatment strategy of thrombus removal. Failure to eliminate acute thrombus from the iliofemoral system leads to chronic postthrombotic obstruction of venous outflow. Debilitating chronic postthrombotic symptoms of the long-standing obstruction of venous outflow can be reduced by restoring unobstructed venous drainage from the profunda femoris vein to the vena cava. © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  6. deep venous thrombosis in patients with acute traumatic spinal cord ...

    African Journals Online (AJOL)

    endothelial injury (trauma) and immobility (venous stasis). DVT and ... pressure ulcers, spasticity and autonomic dysreflexia. (3). ... and its complications saves many lives. Accurate and ..... other chronic diseases and pre-existing risk factors.

  7. Fingertip replantations: importance of venous anastomosis and the clinical results.

    Science.gov (United States)

    Hasuo, Takaaki; Nishi, Genzaburo; Tsuchiya, Daiji; Otsuka, Takanobu

    2009-01-01

    Overall survival rate for 143 digits with complete amputation of the distal phalanx was 78%. Replanted digits that underwent venous anastomosis showed a very high survival rate of 93%. Loss of the distal interphalangeal joint function in subzone IV was significantly inferior to that in subzones II and III. Protective sensation was achieved in 96% of replanted digits. Sensory recovery in the absence of nerve repair was significantly worse for avulsion injury than for crush injury. Nail deformity tended to be increased for replanted digits in subzone III or with crush-type injury. Successful venous anastomosis appears to offer the best way to promote survival of replanted digits. If venous anastomosis is infeasible, a replanted digit can survive with any methods for venous drainage in subzones II and III, but does not survive in subzone IV. To minimise nail deformity, repair of the germinal matrix is necessary.

  8. Color-flow Doppler imaging in suspected extremity venous thrombosis

    International Nuclear Information System (INIS)

    Foley, W.D.; Middleton, W.D.; Lawson, T.L.; Hinson, G.W.; Puller, D.R.

    1987-01-01

    Color-flow Doppler imaging (CFDI) (Quanatum, 5 and 7.5 MHz, linear array) has been performed on 23 extremities (nine positive for venous thrombosis, 14 negative) with venographic correlation. CFDI criteria evaluated were venous color-flow respiratory variation, augmentation, compressibility, valve competence, and intraluminal echogenic filling defects. Both CFDI and venography were evaluated independently and prospectively. CFDI and venography agreed in all six cases of femoral vein thrombosis and eight of nine cases of popliteal vein thrombosis. CFDI was negative in one instance of recanalized popliteal vein thrombosis. Recanalized femoral vein thrombosis was documented in three patients by CFDI when the vein was nonopacified on conventional venography. CFDI provides a rapid and accurate assessment of the femoral popliteal venous system and can distinguish an occluded from a recanalized thrombus. Initial experience with auxiliary subclavian venous thrombus has produced equally accurate results

  9. [Venous thrombosis of atypical location in patients with cancer].

    Science.gov (United States)

    Campos Balea, Begoña; Sáenz de Miera Rodríguez, Andrea; Antolín Novoa, Silvia; Quindós Varela, María; Barón Duarte, Francisco; López López, Rafael

    2015-01-01

    Venous thromboembolism (VTE) is a complication that frequently occurs in patients with neoplastic diseases. Several models have therefore been developed to identify patient subgroups diagnosed with cancer who are at increased risk of developing VTE. The most common forms of thromboembolic episodes are deep vein thrombosis in the lower limbs and pulmonary thromboembolism. However, venous thrombosis is also diagnosed in atypical locations. There are few revisions of unusual cases of venous thrombosis. In most cases, VTE occurs in the upper limbs and in the presence of central venous catheters, pacemakers and defibrillators. We present the case of a patient diagnosed with breast cancer and treated with surgery, chemotherapy and radiation therapy who developed a thrombosis in the upper limbs (brachial and axillary). Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

  10. Central venous oxygen saturation during hypovolaemic shock in humans

    DEFF Research Database (Denmark)

    Madsen, P; Iversen, H; Secher, N H

    1993-01-01

    We compared central venous oxygen saturation and central venous pressure (CVP) as indices of the effective blood volume during 50 degrees head-up tilt (anti-Trendelenburg's position) induced hypovolaemic shock in eight healthy subjects. Head-up tilt increased thoracic electrical impedance from 31...... (28-36) (median and range) to 34 (30-40) Ohm, mean arterial pressure (MAP) from 79 (70-88) to 86 (80-99) mmHg, heart rate (HR) from 67 (56-71) to 99 (78-119) beats min-1 (p ....05) but thereafter remained stable. In contrast, central venous oxygen saturation showed a linear decrease with time from 0.75 (0.69-0.78) at rest to 0.60 (0.49-0.67) (p measurement of central venous oxygen saturation...

  11. Step-Up DC-DC converters

    DEFF Research Database (Denmark)

    Forouzesh, Mojtaba; Siwakoti, Yam P.; Gorji, Saman A.

    2017-01-01

    on the general law and framework of the development of next-generation step-up dc-dc converters, this paper aims to comprehensively review and classify various step-up dc-dc converters based on their characteristics and voltage-boosting techniques. In addition, the advantages and disadvantages of these voltage...

  12. Present trends in HVDC converter station design

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Lennart; Asplund, Gunnar; Bjorklund, Hans; Flisberg, Gunnar [ABB Power Systems AB, Ludvika (Sweden)

    1994-12-31

    HVDC converter station technology has developed rapidly to satisfy increasing requirements during past 10 - 15 years, but there has not been any dramatic changes since thyristor valves were introduced in the mid 70s. This paper describes some recent and expected future developments, that will substantiality change and simplify future converter stations. (author) 4 refs., 7 figs.

  13. Luminescent converter of neodymium laser radiation

    International Nuclear Information System (INIS)

    Ryba-Romanowski, W.; Golab, S.

    1992-01-01

    The new luminescent converter of neodymium laser radiation has been worked out. Activated inorganic compounds of ytterbium and erbium ions has been used as luminescent agent. The multi-component inorganic glass containing tellurium oxide as well as boron, sodium, magnesium and zinc oxides has been applied as a converter matrix

  14. Time-Interleaved Analog to Digital Converters

    NARCIS (Netherlands)

    Louwsma, S.M.; van Tuijl, Adrianus Johannes Maria; Nauta, Bram

    2010-01-01

    This book describes the research carried out by our PhD student Simon Louwsma at the University of Twente, The Netherlands in the field of high-speed Analogto- Digital (AD) converters. AD converters are crucial circuits for modern systems where information is stored or processed in digital form. Due

  15. Switched-mode converters (one quadrant)

    CERN Document Server

    Barrade, P

    2006-01-01

    Switched-mode converters are DC/DC converters that supply DC loads with a regulated output voltage, and protection against overcurrents and short circuits. These converters are generally fed from an AC network via a transformer and a conventional diode rectifier. Switched-mode converters (one quadrant) are non-reversible converters that allow the feeding of a DC load with unipolar voltage and current. The switched-mode converters presented in this contribution are classified into two families. The first is dedicated to the basic topologies of DC/DC converters, generally used for low- to mid-power applications. As such structures enable only hard commutation processes, the main drawback of such topologies is high commutation losses. A typical multichannel evolution is presented that allows an interesting decrease in these losses. Deduced from this direct DC/DC converter, an evolution is also presented that allows the integration of a transformer into the buck and the buck–boost structure. This enables an int...

  16. Controller for a wave energy converter

    Science.gov (United States)

    Wilson, David G.; Bull, Diana L.; Robinett, III, Rush D.

    2015-09-22

    A wave energy converter (WEC) is described, the WEC including a power take off (PTO) that converts relative motion of bodies of the WEC into electrical energy. A controller controls operation of the PTO, causing the PTO to act as a motor to widen a wave frequency spectrum that is usable to generate electrical energy.

  17. Full range ZVS DC-DC converter

    International Nuclear Information System (INIS)

    Upadhyay, Rinki; Badapanda, M.K.; Hannurkar, P.R.

    2011-01-01

    A 500 V, 24 Amp DC-DC converter with digital signal processor (DSP) based control and protection has been designed, fabricated and tested. Its power circuit consists of IGBT based single phase inverter bridge, ferrite transformer and diode rectifier. All IGBTs in the inverter bridge are operated in zero voltage switching (ZVS) mode to minimize switching losses thereby increasing the efficiency of the converter significantly. The efficiency of this converter is measured to be greater than 97% at full load. In a conventional full bridge inverter, typically ZVS is achieved under full load condition while at light load ZVS is lost. An auxiliary LC circuit has been intentionally incorporated in this converter to achieve ZVS even at light loaded conditions. Detailed simulation of the converter circuit is carried out and crucial waveforms have been presented in this paper. Microchip make dsPIC30F2020 DSP is employed to provide phase shifted PWMs to IGBTs in the inverter bridge. All the crucial parameters are also monitored by this DSP and in case of any unfavorable conditions, the converter is tripped off. Suitable experiments were carried out in this DC-DC converter under different loaded conditions and a close match between the simulated and experimental results were obtained. Such DC-DC converters can be connected in series or parallel for the development of solid state modular power supplies for various applications. (author)

  18. Passive Resonant Bidirectional Converter with Galvanic Barrier

    Science.gov (United States)

    Rosenblad, Nathan S. (Inventor)

    2014-01-01

    A passive resonant bidirectional converter system that transports energy across a galvanic barrier includes a converter using at least first and second converter sections, each section including a pair of transfer terminals, a center tapped winding; a chopper circuit interconnected between the center tapped winding and one of the transfer terminals; an inductance feed winding interconnected between the other of the transfer terminals and the center tap and a resonant tank circuit including at least the inductance of the center tap winding and the parasitic capacitance of the chopper circuit for operating the converter section at resonance; the center tapped windings of the first and second converter sections being disposed on a first common winding core and the inductance feed windings of the first and second converter sections being disposed on a second common winding core for automatically synchronizing the resonant oscillation of the first and second converter sections and transferring energy between the converter sections until the voltage across the pairs of transfer terminals achieves the turns ratio of the center tapped windings.

  19. Modeling and Simulation of Matrix Converter

    DEFF Research Database (Denmark)

    Liu, Fu-rong; Klumpner, Christian; Blaabjerg, Frede

    2005-01-01

    This paper discusses the modeling and simulation of matrix converter. Two models of matrix converter are presented: one is based on indirect space vector modulation and the other is based on power balance equation. The basis of these two models is• given and the process on modeling is introduced...

  20. [The unnecessary application of central venous catheterization in surgical patients].

    Science.gov (United States)

    Uemura, Keiko; Inoue, Satoki; Kawaguchi, Masahiko

    2018-04-06

    Perioperative physicians occasionally encounter situations where central venous catheters placed preoperatively turn out to be unnecessary. The purpose of this retrospective study is to identify the unnecessary application of central venous catheter placement and determine the factors associated with the unnecessary application of central venous catheter placement. Using data from institutional perioperative central venous catheter surveillance, we analysed data from 1,141 patients who underwent central venous catheter placement. We reviewed the central venous catheter registry and medical charts and allocated registered patients into those with the proper or with unnecessary application of central venous catheter according to standard indications. Multivariate analysis was used to identify factors associated with the unnecessary application of central venous catheter placement. In 107 patients, representing 9.38% of the overall population, we identified the unnecessary application of central venous catheter placement. Multivariate analysis identified emergencies at night or on holidays (odds ratio [OR] 2.109, 95% confidence interval [95% CI] 1.021-4.359), low surgical risk (OR=1.729, 95% CI 1.038-2.881), short duration of anesthesia (OR=0.961/10min increase, 95% CI 0.945-0.979), and postoperative care outside of the intensive care unit (OR=2.197, 95% CI 1.402-3.441) all to be independently associated with the unnecessary application of catheterization. Complications related to central venous catheter placement when the procedure consequently turned out to be unnecessary were frequently observed (9/107) compared with when the procedure was necessary (40/1034) (p=0.032, OR=2.282, 95% CI 1.076-4.842). However, the subsequent multivariate logistic model did not hold this significant difference (p=0.0536, OR=2.115, 95% CI 0.988-4.526). More careful consideration for the application of central venous catheter is required in cases of emergency surgery at night or on

  1. Venous hypertensive myelopathy associated with cervical spondylosis.

    Science.gov (United States)

    Okada, Seiji; Chang, Charles; Chang, Geraldine; Yue, James J

    2016-11-01

    Venous hypertensive myelopathy (VHM) results from spinal vascular malformations of arteriovenous shunting that increases spinal venous pressure, leading to congestive edema and neurologic dysfunction. There has been no report of VHM associated with cervical spondylotic myelopathy (CSM). The aim of this study was to report an extremely rare case of VHM likely due to CSM. This study is a case report and review of the literature. The patient was a 51-year-old man with CSM exhibiting relatively rapid neurologic deterioration with an abnormal expansion of a centromedullary hyperintense lesion on T2-weighted magnetic resonance imaging (MRI) in the absence of traumatic injury. Neurologic examination and radiologic imaging were taken by various means. The patient developed a cervical radiculopathy, followed by gait disturbance and motor weakness. The MRI of the cervical spine demonstrated spinal canal stenosis due to disc bulging and flavum hypertrophy at the C5/C6 and C6/C7 levels as well as hyperintense area over the C5-C7 levels on T2-weighted images. Although decompression surgery was planned, an acute inflammatory process such as transverse myelitis or demyelinating disease other than cord compression was also considered, and the patient received intravenous steroids. His walking improved for several days. However, his symptoms then became significantly worse, and he had difficulty walking. Subsequent MRI demonstrated marked progression of the T2 hyperintense lesion over the C4-T1 vertebral levels. Flow voids were also noted on the dorsal surface of the upper cervical cord on T2-weighted MRI. His lab work, medical history, and the local enhancement on contrast-enhanced MRI indicated low probability of spinal inflammatory diseases. Therefore, the decision was made to perform anterior cervical discectomy and fusion surgery on two levels. Following surgery, his symptoms improved promptly. Our case indicates that VHM could be caused by spondylotic cord compression in the

  2. Idiopathic versus secondary venous thromboembolism. Findings of the RIETE registry.

    Science.gov (United States)

    Pedrajas, J M; Garmendia, C; Portillo, J; Gabriel, F; Mainez, C; Yera, C; Monreal, M

    2014-10-01

    The Computerized Registry of Patients with Venous Thromboembolism (RIETE) is a prospective registry that consecutively includes patients diagnosed with venous thromboembolism. We compared the clinical presentation and response to anticoagulant treatment in patients with idiopathic venous thromboembolism (IVT) versus secondary venous thromboembolism (SVT, associated with a risk factor). We analyzed the differences in clinical characteristics, comorbidity, treatment and events during the first 3months after the diagnosis of venous thromboembolism in patients with IVT or SVT and according to their initial clinical presentation. A total of 39,921 patients with IVT (n=18,029; 45.1%) or SVT (n=21,892; 54.9%) were enrolled. The patients with IVT had a greater history of venous thromboembolism than those diagnosed with SVT (p<.001). The initial treatment was similar for the 2 groups, but more inferior vena cava filters were placed in the SVT group (p<.001). In the long term, low-molecular-weight heparin was used more often in the SVT group than in the IVT group. At 90days, bleeding, death and the recurrence of venous thromboembolism were significantly more frequent in the SVT group. The multivariate analysis confirmed that IVT was associated with fewer major (OR, 0.60; 95%CI, 0.50-0.61; p<.001) and fatal (OR, 0.41; 95%CI, 0.29-0.62; p<.001) bleedings, fewer relapses (OR, 0.58; 95%CI, 0.39-0.78; p<.001) and fewer fatal pulmonary embolisms (OR, 0.29; 95%CI, 0.12-0.52; p<.001). These differences were maintained in patients whose venous thromboembolism started with a pulmonary embolism or with deep vein thrombosis. IVT has a better prognosis than SVT at 90days of the diagnosis. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  3. ANKYLOSING SPONDYLITIS - AN ALARMING RISK OF VENOUS THROMBOEMBOLIC DISEASE

    OpenAIRE

    Dr. Darpanarayan Hazra; Dr. Shahid Mahdi; Dr. Amit Madan; Dr. Neeraj Bhalla

    2017-01-01

    Venous thrombo-embolic disease (VTE) is a potentially life threatening clinical event. Ankylosing spondylitis (AS) is a chronic inflammatory disease with a significantly increased risk of developing VTE. Management of acute proximal deep venous thrombosis (DVT) depends on the clinical status of the affected limb, extent of the thrombus and comorbidities of the patient. Semba and Dake introduced Catheter directed thrombolysis (CDT) to treat 21 patients of DVT in 1994. CDT is a life or limb sav...

  4. How to objectively assess jugular primary venous obstruction

    OpenAIRE

    Paolo Zamboni

    2014-01-01

    Last January The Lancet published the article by Traboulsee et al. Prevalence of extracranial venous narrowing on catheter venography in people with multiple sclerosis, their sibilings, and unrelated healthy controls: a blinded, case control study. These Authors confirmed the presence of chronic cerebrospinal venous insufficiency with a high prevalence of about 70% in the Canadian population, but without significant differences between patients and healthy controls, yet. However, they used a ...

  5. Total anomalous systemic venous drainage in left heterotaxy syndrome.

    Science.gov (United States)

    Khandenahally, Ravindranath S; Deora, Surender; Math, Ravi S

    2013-04-01

    Total anomalous systemic venous drainage is an extremely rare congenital heart defect. In this study we describe an 11-year-old girl who presented with a history of fatigue and central cyanosis that she had had since early childhood with unremarkable precordial examination results. Investigations revealed left heterotaxy with all systemic venous drainage to the left-sided atrium with non-compaction of the left ventricle.

  6. Sustained compression and healing of chronic venous ulcers.

    OpenAIRE

    Blair, S. D.; Wright, D. D.; Backhouse, C. M.; Riddle, E.; McCollum, C. N.

    1988-01-01

    STUDY OBJECTIVE--Comparison of four layer bandage system with traditional adhesive plaster bandaging in terms of (a) compression achieved and (b) healing of venous ulcers. DESIGN--Part of larger randomised trial of five different dressings. SETTING--Outpatient venous ulcer clinic in university hospital. PATIENTS--(a) Pressure exerted by both bandage systems was measured in the same 20 patients. (b) Healing with the four layer bandage was assessed in 148 legs in 126 consecutive patients (mean ...

  7. A novel power converter for photovoltaic applications

    Science.gov (United States)

    Yuvarajan, S.; Yu, Dachuan; Xu, Shanguang

    A simple and economical power conditioner to convert the power available from solar panels into 60 Hz ac voltage is described. The raw dc voltage from the solar panels is converted to a regulated dc voltage using a boost converter and a large capacitor and the dc output is then converted to 60 Hz ac using a bridge inverter. The ratio between the load current and the short-circuit current of a PV panel at maximum power point is nearly constant for different insolation (light) levels and this property is utilized in designing a simple maximum power point tracking (MPPT) controller. The controller includes a novel arrangement for sensing the short-circuit current without disturbing the operation of the PV panel and implementing MPPT. The switching losses in the inverter are reduced by using snubbers. The results obtained on an experimental converter are presented.

  8. Step-Up DC-DC converters

    DEFF Research Database (Denmark)

    Forouzesh, Mojtaba; Siwakoti, Yam P.; Gorji, Saman A.

    2017-01-01

    on the general law and framework of the development of next-generation step-up dc-dc converters, this paper aims to comprehensively review and classify various step-up dc-dc converters based on their characteristics and voltage-boosting techniques. In addition, the advantages and disadvantages of these voltage......DC-DC converters with voltage boost capability are widely used in a large number of power conversion applications, from fraction-of-volt to tens of thousands of volts at power levels from milliwatts to megawatts. The literature has reported on various voltage-boosting techniques, in which......-boosting techniques and associated converters are discussed in detail. Finally, broad applications of dc-dc converters are presented and summarized with comparative study of different voltage-boosting techniques....

  9. A review of Indirect Matrix Converter Topologies

    Directory of Open Access Journals (Sweden)

    Salem Rahmani

    2015-08-01

    Full Text Available Abstract—Matrix Converter (MC is a modern direct AC/AC electrical power converter without dc-link capacitor. MC is operated in four quadrant, assuring a control of the output voltage, amplitude and frequency. The matrix converter has recently attracted significant attention among researchers and it has become increasing attractive for applications of wind energy conversion, military power supplies, induction motor drives, etc. Recently, different MC topologies have been proposed and developed which have their own advantages and disadvantages. Matrix converter can be classified as direct and indirect structures. The direct one has been elaborated in previous work. In this paper the indirect MCs are reviewed. Different characteristics of the indirect MC topologies are mentioned to show the strengths and weaknesses of such converter topologies.

  10. Relationship between newborn Acid-Base status and umbilical cord morphology

    Directory of Open Access Journals (Sweden)

    Marssosi V

    2001-06-01

    Full Text Available ess the relationship between umbilical cord blood gases at birth and morphology of umbilical cord, in a prospective study of 200 consecutive term delivery, we investigated the relationship between umbilical cord morphology characteristics (umbilical crd length, number of vascular coil, coiling index and color of amniotic fluid and umbilical vessel blood gases. Statistically significant linear correlation was found between umblicial venous PH and the umbilical cord length (r=0.39, 95% CI 0.25, 0.53, P<0.03, umber of vascular coils (r=0.45 95% CI 0.31-0.59 P<0.012, and coiling index (r=0.34, 95% CI 0.12-0.48, P<0.04, and also negative linear correlation was found between umbilical venous partial pressure of carbon dioxide & of coli (r=0.3, 95% CI –0.44, -0.16 P<0.03. No relation was found between umbilical cord indices and meconium staining of amniotic fluid.Placental weight also correlated with umbilical cord length (r=0.17, 95% CI 0.03-0.31, P<0.03, but not with umbilical cord coils or coiling index.Umbilical venous pH is related to umbilical cord morphology but umbilical venous PCO2 was only related to the number of coils and umbilicat artery pH wa only related to the number of coils and not related to length or coiling index of umbilical cord morphology. The morphology of umbilical cord can affect maternal-fetal gas exchange

  11. Fish Intake and Venous Thromboembolism: A Systematic Literature Review.

    Science.gov (United States)

    Mattiuzzi, Camilla; Cervellin, Gianfranco; Franchini, Massimo; Lippi, Giuseppe

    2016-05-01

    Diet plays an important role in modulating the risk of arterial and venous thrombosis. Several lines of evidence attest that consumption of fish and its compounds, especially omega-3 fatty acids, may be effective to decrease the cardiovascular risk. Since the pathogenesis of arterial and venous thrombosis share some common aspects, we performed a systematic review of published clinical studies that investigated the association between fish intake and venous thrombosis. An electronic search was carried out in Medline, Scopus, and ISI Web of Science using the key words "fish" OR "seafood" AND "venous thromboembolism" OR "deep vein thrombosis" OR "pulmonary embolism", with no language or date restriction. Overall, 6 studies (5 prospective and 1 case-control) were finally identified. In only 1 small case-control study, a larger intake of total fish was found to be negatively associated with the risk of venous thromboembolism. No association was found in 4 large prospective studies, whereas a positive association was observed in the remaining. No substantial difference was also noticed between intake of fatty or lean fish. Taken together, the current epidemiological evidence does not support the existence of a significant effect of total fish consumption on the risk of venous thromboembolism. © The Author(s) 2015.

  12. Portal-venous gas unrelated to mesenteric ischemia

    International Nuclear Information System (INIS)

    Wiesner, Walter; Mortele, Koenraad J.; Ji, Hoon; Ros, Pablo R.; Glickman, Jonathan N.

    2002-01-01

    The aim of this study was to report on 8 patients with all different non-ischemic etiologies for portal-venous gas and to discuss this rare entity and its potentially misleading CT findings in context with a review of the literature. The CT examinations of eight patients who presented with intrahepatic portal-venous gas, unrelated to bowel ischemia or infarction, were reviewed and compared with their medical records with special emphasis on the pathogenesis and clinical impact of portal-venous gas caused by non-ischemic conditions. The etiologies for portal-venous gas included: abdominal trauma (n=1); large gastric cancer (n=1); prior gastroscopic biopsy (n=1); prior hemicolectomy (n=1); graft-vs-host reaction (n=1); large paracolic abscess (n=1); mesenteric recurrence of ovarian cancer superinfected with clostridium septicum (n=1); and sepsis with Pseudomonas aeruginosa (n=1). The clinical outcome of all patients was determined by their underlying disease and not negatively influenced by the presence of portal-venous gas. Although the presence of portal-venous gas usually raises the suspicion of bowel ischemia and/or intestinal necrosis, this CT finding may be related to a variety of non-ischemic etiologies and pathogeneses as well. The knowledge about these conditions may help to avoid misinterpretation of CT findings, inappropriate clinical uncertainty and unnecessary surgery in certain cases. (orig.)

  13. Visualization of coronary venous anatomy by cardiovascular magnetic resonance

    Directory of Open Access Journals (Sweden)

    Crean Andrew

    2009-08-01

    Full Text Available Abstract Background Coronary venous imaging with whole-heart cardiovascular magnetic resonance (CMR angiography has recently been described using developmental pulse sequences and intravascular contrast agents. However, the practical utility of coronary venous imaging will be for patients with heart failure in whom cardiac resynchronisation therapy (CRT is being considered. As such complementary information on ventricular function and myocardial viability will be required. The aim of this study was to determine if the coronary venous anatomy could be depicted as part of a comprehensive CMR protocol and using a standard extracellular contrast agent. Methods and Results Thirty-one 3D whole heart CMR studies, performed after intravenous administration of 0.05 mmol/kg gadolinium DTPA, were reviewed. The cardiac venous system was visualized in all patients. The lateral vein of the left ventricle was present in 74%, the anterior interventricular vein in 65%, and the posterior interventricular vein in 74% of patients. The mean maximum distance of demonstrable cardiac vein on the 3D images was 81.5 mm and was dependent on the quality of the 3D data set. Five patients showed evidence of myocardial infarction on late gadolinium enhancement (LGE images. Conclusion Coronary venous anatomy can be reliably demonstrated using a comprehensive CMR protocol and a standard extracellular contrast agent. The combination of coronary venous imaging, assessment of ventricular function and LGE may be useful in the management of patients with LV dysfunction being considered for CRT.

  14. Venous compression syndrome of internal jugular veins prevalence in patients with multiple sclerosis and chronic cerebro-spinal venous insufficiency.

    Science.gov (United States)

    Mandolesi, Sandro; Niglio, Tarcisio; Orsini, Augusto; De Sio, Simone; d'Alessandro, Alessandro; Mandolesi, Dimitri; Fedele, Francesco; d'Alessandro, Aldo

    2016-01-01

    Analysis of the incidence of Venous Compression Syndrome (VCS) with full block of the flow of the internal jugular veins (IJVs) in patients with Multiple Sclerosis and Chronic cerebro-spinal venous insufficiency. We included 769 patients with MS and CCSVI (299 males, 470 females) and 210 controls without ms and ccsvi (92 males, 118 females). each subject was investigated by echo-color-doppler (ecd). morphological and hemodynamic ecd data were recorded by a computerized mem-net maps of epidemiological national observatory on ccsvi and they were analyzed by mem-net clinical analysis programs. VCS of IJVs occurs in 240 subjects affected by CCSVI and MS (31% of total) and in 12 controls (6% of total). The differences between the two groups are statistical significant (X² = 36.64, pCerebro-Spinal Venous Insufficiency, Multiple Sclerosis, Venous Compression Syndrome.

  15. Pulmonary Venous Obstruction in Cancer Patients

    Directory of Open Access Journals (Sweden)

    Chuang-Chi Liaw

    2015-01-01

    Full Text Available Background. We study the clinical significance and management of pulmonary venous obstruction in cancer patients. Methods. We conducted a prospective cohort study to characterize the syndrome that we term “pulmonary vein obstruction syndrome” (PVOS between January 2005 and March 2014. The criteria for inclusion were (1 episodes of shortness of breath; (2 chest X-ray showing abnormal pulmonary hilum shadow with or without presence of pulmonary edema and/or pleural effusion; (3 CT scan demonstrating pulmonary vein thrombosis/tumor with or without tumor around the vein. Results. Two hundred and twenty-two patients developed PVOS. Shortness of breath was the main symptom, which was aggravated by chemotherapy in 28 (13%, and medical/surgical procedures in 21 (9% and showed diurnal change in intensity in 32 (14%. Chest X-rays all revealed abnormal pulmonary hilum shadows and presence of pulmonary edema in 194 (87% and pleural effusion in 192 (86%. CT scans all showed pulmonary vein thrombosis/tumor (100% and surrounding the pulmonary veins by tumor lesions in 140 patients (63%. PVOS was treated with low molecular weight heparin in combination with dexamethasone, and 66% of patients got clinical/image improvement. Conclusion. Physicians should be alert to PVOS when shortness of breath occurs and chest X-ray reveals abnormal pulmonary hilum shadows.

  16. Bilateral Pneumothoraces Following Central Venous Cannulation

    Directory of Open Access Journals (Sweden)

    F. Pazos

    2009-01-01

    Full Text Available We report the occurrence of a bilateral pneumothoraces after unilateral central venous catheterization of the right subclavian vein in a 70-year-old patient. The patient had no history of pulmonary or pleural disease and no history of cardiothoracic surgery. Two days earlier, she had a median laparotomy under general and epidural anaesthesia. Prior to the procedure, the patient was hemodynamically stable and her transcutaneous oxygen saturation was 97% in room air. We punctured the right pleural space before cannulation of the right subclavian vein. After the procedure, the patient slowly became hemodynamically instable with respiratory distress. A chest radiograph revealed a complete left-side pneumothorax and a mild right-side pneumothorax. The right-side pneumothorax became under tension after left chest tube insertion. The symptoms finally resolved after insertion of a right chest tube. After a diagnostic work-up, we suspect a congenital “Buffalo chests” explaining bilateral pneumothoraces and a secondary tension pneumothorax.

  17. Unilateral papilledema in cerebral venous sinus thrombosis

    Directory of Open Access Journals (Sweden)

    Girish Baburao Kulkarni

    2017-01-01

    Full Text Available In the majority of patients with raised intracranial pressure, the papilledema is bilateral. Unilateral papilledema is rare in conditions causing intracranial hypertension, and it has been described in Foster–Kennedy syndrome and in some cases of idiopathic intracranial hypertension. It has never been reported in cerebral venous thrombosis. We report a young lady presenting with features of subacute onset of headache with seizures, on evaluation she had superior sagittal and bilateral lateral sinus thrombosis. The risk factors found on evaluation were Vitamin B12 deficiency and hyperhomocysteinemia. On optic fundus examination, she had swollen optic disc on the right side with normal fundus on the left side, confirmed with the orbital ultrasound B-scan and optic coherence tomography. Her magnetic resonance imaging showed features of raised intracranial pressure with thrombosis of the superior sagittal and bilateral lateral sinus thrombosis. She was treated with anticoagulation (heparin followed by oral anticoagulants, antiedema measures, and vitamin supplementation for hyperhomocysteinemia. She improved over time and was asymptomatic during follow-up. We discuss the possible mechanisms described in the literature for unilateral papilledema. This report highlights the need for carefully performing bilateral fundus examination so as not to miss the vision or life-threatening causes of a headache.

  18. Cerebral (31)P magnetic resonance spectroscopy and systemic acid-base balance during hypoxia in fetal sheep.

    NARCIS (Netherlands)

    Cappellen van Walsum, A.M. van; Rijpkema, M.J.P.; Heerschap, A.; Oeseburg, B.; Nijhuis, J.G.; Jongsma, H.W.

    2003-01-01

    The purpose of this study was to investigate cerebral energy metabolism and acid-base homeostasis during impaired oxygen supply in fetal sheep. Systemic acid-base balance was correlated with the sequence in changes of cerebral phosphorus metabolite ratios and intracellular pH. Phosphorus magnetic

  19. Compression of the posterior fossa venous sinuses by epidural hemorrhage simulating venous sinus thrombosis: CT and MR findings

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Sumit; Ramakrishnaiah, Raghu H.; Hegde, Shilpa V.; Glasier, Charles M. [University of Arkansas for Medical Sciences, Pediatric Radiology, Little Rock, AR (United States)

    2016-01-15

    Posterior fossa dural venous sinus thrombus is a well-described complication of head trauma, especially when fracture crosses the dural sinus grooves or in association with epidural hemorrhage. We have found that post-traumatic posterior fossa epidural hematoma compressing a dural venous sinus can mimic dural venous thrombus. To discuss the CT and MRI findings of posterior fossa epidural hemorrhages simulating sinus thrombosis, to make radiologists aware of this important imaging pitfall. We describe radiologic findings in four children in whom a posterior fossa epidural hemorrhage mimicked dural venous sinus thrombus. Routine CT head and CT venography were obtained on Toshiba volume and helical CT scanners. MRI and MR venography were performed on a Philips scanner. In all cases there was medial displacement and compression of the posterior fossa dural venous sinuses without intraluminal thrombosis. The epidural hemorrhage was seen tracking along sinus grooves in the occipital bone, peeling the dura containing the sinuses from the calvarium and compressing the sinus, simulating thrombosis on axial CT views. Both venous sinus thrombosis and posterior fossa epidural hemorrhages in children are well-described complications of head trauma. Posterior fossa epidural hemorrhage can mimic a sinus thrombus by compressing and displacing the sinuses. It is important to recognize this pitfall because treatment of a suspected thrombus with anticoagulation can worsen epidural hemorrhage. (orig.)

  20. Compression of the posterior fossa venous sinuses by epidural hemorrhage simulating venous sinus thrombosis: CT and MR findings

    International Nuclear Information System (INIS)

    Singh, Sumit; Ramakrishnaiah, Raghu H.; Hegde, Shilpa V.; Glasier, Charles M.

    2016-01-01

    Posterior fossa dural venous sinus thrombus is a well-described complication of head trauma, especially when fracture crosses the dural sinus grooves or in association with epidural hemorrhage. We have found that post-traumatic posterior fossa epidural hematoma compressing a dural venous sinus can mimic dural venous thrombus. To discuss the CT and MRI findings of posterior fossa epidural hemorrhages simulating sinus thrombosis, to make radiologists aware of this important imaging pitfall. We describe radiologic findings in four children in whom a posterior fossa epidural hemorrhage mimicked dural venous sinus thrombus. Routine CT head and CT venography were obtained on Toshiba volume and helical CT scanners. MRI and MR venography were performed on a Philips scanner. In all cases there was medial displacement and compression of the posterior fossa dural venous sinuses without intraluminal thrombosis. The epidural hemorrhage was seen tracking along sinus grooves in the occipital bone, peeling the dura containing the sinuses from the calvarium and compressing the sinus, simulating thrombosis on axial CT views. Both venous sinus thrombosis and posterior fossa epidural hemorrhages in children are well-described complications of head trauma. Posterior fossa epidural hemorrhage can mimic a sinus thrombus by compressing and displacing the sinuses. It is important to recognize this pitfall because treatment of a suspected thrombus with anticoagulation can worsen epidural hemorrhage. (orig.)

  1. Electromagnetic Compatibility of Matrix Converter System

    Directory of Open Access Journals (Sweden)

    S. Fligl

    2006-12-01

    Full Text Available The presented paper deals with matrix converters pulse width modulation strategies design with emphasis on the electromagnetic compatibility. Matrix converters provide an all-silicon solution to the problem of converting AC power from one frequency to another, offering almost all the features required of an ideal static frequency changer. They possess many advantages compared to the conventional voltage or current source inverters. A matrix converter does not require energy storage components as a bulky capacitor or an inductance in the DC-link, and enables the bi-directional power flow between the power supply and load. The most of the contemporary modulation strategies are able to provide practically sinusoidal waveforms of the input and output currents with negligible low order harmonics, and to control the input displacement factor. The perspective of matrix converters regarding EMC in comparison with other types of converters is brightly evident because it is no need to use any equipment for power factor correction and current and voltage harmonics reduction. Such converter with proper control is properly compatible both with the supply mains and with the supplied load. A special digital control system was developed for the realized experimental test bed which makes it possible to achieve greater throughput of the digital control system and its variability.

  2. Underwater noise from a wave energy converter

    DEFF Research Database (Denmark)

    Tougaard, Jakob

    A recent addition to the anthropogenic sources of underwater noise is offshore wave energy converters. Underwater noise was recorded from the Wavestar wave energy converter located at Hastholm, Denmark (57°7.73´N, 8°37.23´E). The Wavestar is a full-scale test and demonstration converter...... in full operation and start and stop of the converter. Median broad band (10 Hz – 20 kHz) sound pressure level (Leq) was 123 dB re. 1 Pa, irrespective of status of the wave energy converter (stopped, running or starting/stopping). The most pronounced peak in the third-octave spectrum was in the 160 Hz...... significant noise above ambient could be detected above the 250 Hz band. The absolute increase in noise above ambient was very small. L50 third-octave levels in the four bands with the converter running were thus only 1-2 dB above ambient L50 levels. The noise recorded 25 m from the wave energy converter...

  3. Acid-Base Behavior in Hydrothermal Processing of Wastes - Final Report

    International Nuclear Information System (INIS)

    Johnston, K.; Rossky, P.

    2000-01-01

    A major obstacle to development of hydrothermal oxidation technology has been a lack of scientific knowledge of chemistry in hydrothermal solution above 350 C, particularly acid-base behavior, and transport phenomena, which is needed to understand corrosion, metal-ion complexation, and salt precipitation and recovery. Our objective has been to provide this knowledge with in situ UV-visible spectroscopic measurements and fully molecular computer simulation. Our recent development of relatively stable organic UV-visible pH indicators for supercritical water oxidation offers the opportunity to characterize buffers and to monitor acid-base titrations. These results have important implications for understanding reaction pathways and yields for decomposition of wastes in supercritical water

  4. ENVIRONMENTAL LEARNING APPROACHES IN IMPROVING LEARNING OUTCOMES IN ACID-BASE SUBJECT

    Directory of Open Access Journals (Sweden)

    Rachmat Sahputra

    2016-03-01

    Full Text Available Learning in the understanding of acid-base chemistry in schools needs to be improved so research to determine differences in learning outcomes between students taught using environmental approaches and methods lectures in class XI SMA on acid-base subject needs to be done. In this study, using a quasi-experimental method using a data collection tool achievement test essay form. The test statistic results of the post-test learning has been obtained Asymp value. Sig (2-tailed 0,026 that showed the differences between students' learning outcomes with a control experimental class with effect size of 0.63 or much influence difference with the percentage 23.57% which indicated that the learning environment approach can improve learning outcomes of high school students.

  5. Bicarbonate sensing in mouse cortical astrocytes during extracellular acid/base disturbances

    Science.gov (United States)

    Naoshin, Zinnia; Defren, Sabrina; Schmaelzle, Jana; Weber, Tobias; Schneider, Hans‐Peter

    2017-01-01

    Key points The present study suggests that the electrogenic sodium–bicarbonate cotransporter, NBCe1, supported by carbonic anhydrase II, CAII, provides an efficient mechanism of bicarbonate sensing in cortical astrocytes. This mechanism is proposed to play a major role in setting the pHi responses to extracellular acid/base challenges in astrocytes.A decrease in extracellular [HCO3 −] during isocapnic acidosis and isohydric hypocapnia, or an increase in intracellular [HCO3 −] during hypercapnic acidosis, was effectively sensed by NBCe1, which carried bicarbonate out of the cells under these conditions, and caused an acidification and sodium fall in WT astrocytes, but not in NBCe1‐knockout astrocytes.Isocapnic acidosis, hypercapnic acidosis and isohydric hypocapnia evoked inward currents in NBCe1‐ and CAII‐expressing Xenopus laevis oocytes, but not in native oocytes, suggesting that NBCe1 operates in the outwardly directed mode under these conditions consistent with our findings in astrocytes.We propose that bicarbonate sensing of astrocytes may have functional significance during extracellular acid/base disturbances in the brain, as it not only alters intracellular pH/[HCO3 −]‐dependent functions of astrocytes, but also modulates the extracellular pH/[HCO3 −] in brain tissue. Abstract Extracellular acid/base status of the mammalian brain undergoes dynamic changes during many physiological and pathological events. Although intracellular pH (pHi) of astrocytes responds to extracellular acid/base changes, the mechanisms mediating these changes have remained unresolved. We have previously shown that the electrogenic sodium–bicarbonate cotransporter, NBCe1, is a high‐affinity bicarbonate carrier in cortical astrocytes. In the present study, we investigated whether NBCe1 plays a role in bicarbonate sensing in astrocytes, and in determining the pHi responses to extracellular acid/base challenges. We measured changes in intracellular H+ and Na+ in

  6. Optical Absorption and Electron Injection of 4-(Cyanomethylbenzoic Acid Based Dyes: A DFT Study

    Directory of Open Access Journals (Sweden)

    Yuehua Zhang

    2015-01-01

    Full Text Available Density functional theory (DFT and time-dependent density functional theory (TDDFT calculations were carried out to study the ground state geometries, electronic structures, and absorption spectra of 4-(cyanomethylbenzoic acid based dyes (AG1 and AG2 used for dye-sensitized solar cells (DSSCs. The excited states properties and the thermodynamical parameters of electron injection were studied. The results showed that (a two dyes have uncoplanar structures along the donor unit and conjugated bridge space, (b two sensitizers exhibited intense absorption in the UV-Vis region, and (c the excited state oxidation potential was higher than the conduction band edge of TiO2 photoanode. As a result, a solar cell based on the 4-(cyanomethylbenzoic acid based dyes exhibited well photovoltaic performance. Furthermore, nine dyes were designed on the basis of AG1 and AG2 to improve optical response and electron injection.

  7. Acid-Base Disorders in Patients with Chronic Obstructive Pulmonary Disease: A Pathophysiological Review

    Directory of Open Access Journals (Sweden)

    Cosimo Marcello Bruno

    2012-01-01

    Full Text Available The authors describe the pathophysiological mechanisms leading to development of acidosis in patients with chronic obstructive pulmonary disease and its deleterious effects on outcome and mortality rate. Renal compensatory adjustments consequent to acidosis are also described in detail with emphasis on differences between acute and chronic respiratory acidosis. Mixed acid-base disturbances due to comorbidity and side effects of some drugs in these patients are also examined, and practical considerations for a correct diagnosis are provided.

  8. The discovery of glycine and related amino acid-based factor Xa inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Kohrt, Jeffrey T.; Filipski, Kevin J.; Cody, Wayne L.; Bigge, Christopher F.; La, Frances; Welch, Kathleen; Dahring, Tawny; Bryant, John W.; Leonard, Daniele; Bolton, Gary; Narasimhan, Lakshmi; Zhang, Erli; Peterson, J. Thomas; Haarer, Staci; Sahasrabudhe, Vaishali; Janiczek, Nancy; Desiraju, Shrilakshmi; Hena, Mostofa; Fiakpui, Charles; Saraswat, Neerja; Sharma, Raman; Sun, Shaoyi; Maiti, Samarendra N.; Leadley, Robert; Edmunds, Jeremy J. (Naeja); (Pfizer)

    2010-12-03

    Herein, we report on the identification of three potent glycine and related amino acid-based series of FXa inhibitors containing a neutral P1 chlorophenyl pharmacophore. A X-ray crystal structure has shown that constrained glycine derivatives with optimized N-substitution can greatly increase hydrophobic interactions in the FXa active site. Also, the substitution of a pyridone ring for a phenylsulfone ring in the P4 sidechain resulted in an inhibitor with enhanced oral bioavailability.

  9. TREATMENT WITH AMINO-ACID-BASED FORMULA OF CHILDREN WITH ALIMENTARY ALLERGY TO COW MILK PROTEINS

    Directory of Open Access Journals (Sweden)

    E. I. Vishneva

    2012-01-01

    Full Text Available The prevalence of alimentary allergy in children of the 1st year of life is increasing overall. This kind of disorders involves different organs and tissues, and its clinical manifestations are not pathognomic. Among the most important allergens one of the key roles play cow milk proteins. Hypoallergenic formulas are recommended for the non-invasive dietary diagnostics and treatment. Amino-acid-based formulas meet the criteria of being hypoallergenic.

  10. Acid-base properties of 2-phenethyldithiocarbamoylacetic acid, an antitumor agent

    Science.gov (United States)

    Novozhilova, N. E.; Kutina, N. N.; Petukhova, O. A.; Kharitonov, Yu. Ya.

    2013-07-01

    The acid-base properties of the 2-phenethyldithiocarbamoylacetic acid (PET) substance belonging to the class of isothiocyanates and capable of inhibiting the development of tumors on many experimental models were studied. The acidity and hydrolysis constants of the PET substance in ethanol, acetone, aqueous ethanol, and aqueous acetone solutions were determined from the data of potentiometric (pH-metric) titration of ethanol and acetone solutions of PET with aqueous solidum hydroxide at room temperature.

  11. Acid-base and ion balance in fishes with bimodal respiration.

    Science.gov (United States)

    Shartau, R B; Brauner, C J

    2014-03-01

    The evolution of air breathing during the Devonian provided early fishes with bimodal respiration with a stable O2 supply from air. This was, however, probably associated with challenges and trade-offs in terms of acid-base balance and ionoregulation due to reduced gill:water interaction and changes in gill morphology associated with air breathing. While many aspects of acid-base and ionoregulation in air-breathing fishes are similar to water breathers, the specific cellular and molecular mechanisms involved remain largely unstudied. In general, reduced ionic permeability appears to be an important adaptation in the few bimodal fishes investigated but it is not known if this is a general characteristic. The kidney appears to play an important role in minimizing ion loss to the freshwater environment in the few species investigated, and while ion uptake across the gut is probably important, it has been largely unexplored. In general, air breathing in facultative air-breathing fishes is associated with an acid-base disturbance, resulting in an increased partial pressure of arterial CO2 and a reduction in extracellular pH (pHE ); however, several fishes appear to be capable of tightly regulating tissue intracellular pH (pHI ), despite a large sustained reduction in pHE , a trait termed preferential pHI regulation. Further studies are needed to determine whether preferential pHI regulation is a general trait among bimodal fishes and if this confers reduced sensitivity to acid-base disturbances, including those induced by hypercarbia, exhaustive exercise and hypoxia or anoxia. Additionally, elucidating the cellular and molecular mechanisms may yield insight into whether preferential pHI regulation is a trait ultimately associated with the early evolution of air breathing in vertebrates. © 2014 The Fisheries Society of the British Isles.

  12. [Evaluation of the Charing Cross Venous Ulcer Questionnaire in patients with chronic venous ulcers in Uruguay].

    Science.gov (United States)

    Tafernaberry, Gabriela; Otero, Gabriela; Agorio, Caroline; Dapueto, Juan J

    2016-01-01

    Chronic venous ulcers (CVU) represent a frequent condition, with difficult therapeutic approaches, that impact on patients’ quality of life, and generate an economic burden to patients and health systems. To perform the cultural adaptation and initial evaluation of the Charing Cross Venous Ulcer Questionnaire (CCVUQ) for Uruguay, and to study the health-related quality of life (HRQL) of patients with CVU. The translated and culturally adapted version of the CCVUQ was applied to a convenience sample of 50 patients. In addition, the PROMIS Global Health Survey was included in the assessment. Both questionnaires showed good internal consistency (Cronbach alfa > 0.70). A statistically significant association was observed between the CCVUQ total scores, its subscales and both dimensions of the PROMIS: Global Physical (GPH) and Global Mental Health (GMH) (rho ≥ 0.40). The CCVUQ mean score was 54.9 ± 42 points while GPH and GMH mean scores were 37.9 ± 29 points, and 43.1 ± 35.1 points respectively. Simple linear regression showed that patients with higher income reported better emotional well-being, while in younger patients, ulcers had a higher impact on Emotional Status and Cosmetics. The translated and adapted version of the CCVUQ was easy to comprehend and apply, showing good psychometric properties. When used in association with the PROMIS Global Health Measure it provides complementary information. HRQL was severely affected in the study sample.

  13. CAS - CERN Accelerator School: Power Converters

    CERN Document Server

    2015-01-01

    These proceedings collate lectures given at the twenty-eighth specialized course organised by the CERN Accelerator School (CAS). The course was held at the Hotel du Parc, Baden, Switzerland from 7 - 14 May 2014, in collaboration with the Paul Scherrer Institute. Following introductory lectures on accelerators and the requirements on power converters, the course covered components and topologies of the different types of power converters needed for particle accelerators. Issues of design, control and exploitation in a sometimes-hostile environment were addressed. Site visits to ABB and PSI provided an insight into state-of-the-art power converter production and operation, while topical seminars completed the programme.

  14. High-power converters and AC drives

    CERN Document Server

    Wu, Bin

    2017-01-01

    This new edition reflects the recent technological advancements in the MV drive industry, such as advanced multilevel converters and drive configurations. It includes three new chapters, Control of Synchronous Motor Drives, Transformerless MV Drives, and Matrix Converter Fed Drives. In addition, there are extensively revised chapters on Multilevel Voltage Source Inverters and Voltage Source Inverter-Fed Drives. This book includes a systematic analysis on a variety of high-power multilevel converters, illustrates important concepts with simulations and experiments, introduces various megawatt drives produced by world leading drive manufacturers, and addresses practical problems and their mitigations methods.

  15. Field Data Logger Prototype for Power Converters

    DEFF Research Database (Denmark)

    Chaudhary, Sanjay; Ghimire, Pramod; Thøgersen, Paul Bach

    2014-01-01

    and subsequent analysis of the data. This paper presents the development of a low cost prototype field data logger prototype using Raspberry PI and industrial sensors. The functionalities of the data logger prototype are described. An online rainflow count algorithm has been implemented as well.......Mission profile data is very important for the cost effective and reliable design of power converters. The converter design can be improved on the basis of actual field data. Actual mission profile data can be collected for the power converters using field data loggers over a long period of time...

  16. Synchronous Control of Modular Multilevel Converters

    DEFF Research Database (Denmark)

    Oleschuk, Valentin; Blaabjerg, Frede; Bose, Bimal K.

    2002-01-01

    A novel method of direct synchronous pulsewidth modulation (PWM) is applied for control of modular multilevel converters consisting from three standard triphase inverter modules along with an 0.33 p.u. output transformer. The proposed method provides synchronisation of the voltage waveforms...... for each module and the composed voltage at the output of the converter. Multilevel output voltage of the converter has quarter-wave symmetry during the whole range including the zone of overmodulation. Both continuous and discontinuous versions of synchronous PWM, based on vector approach...

  17. NaVirCept - Nucleic Acid-Based Anti-Viral Project

    International Nuclear Information System (INIS)

    Stephen, E. R.; Wong, J.; Van Loon, D.

    2007-01-01

    Vaccines are generally considered to be the most effective countermeasures to bacterial and viral diseases, however, licensed vaccines against many disease agents are either not available or their efficacies have not been demonstrated. Vaccines are generally agent specific in terms of treatment spectrum and are subject to defeat through natural mutation or through directed efforts. With respect to viral therapeutics, one of the major limitations associated with antiviral drugs is acquired drug resistance caused by antigenic shift or drift. A number of next-generation prophylactic and/or therapeutic measures are on the horizon. Of these, nucleic acid-based drugs are showing great antiviral potential. These drugs elicit long-lasting, broad spectrum protective immune responses, especially to respiratory viral pathogens. The Nucleic Acid-Based Antiviral (NaVirCept) project provides the opportunity to demonstrate the effectiveness of novel medical countermeasures against military-significant endemic and other viral threat agents. This project expands existing DRDC drug delivery capability development, in the form of proprietary liposome intellectual property, by coupling it with leading-edge nucleic acid-based technology to deliver effective medical countermeasures that will protect deployed personnel and the warfighter against a spectrum of viral disease agents. The technology pathway will offer a means to combat emerging viral diseases or modified threat agents such as the bird flu or reconstructed Spanish flu without going down the laborious, time-consuming and expensive paths to develop countermeasures for each new and/or emerging viral disease organism.(author)

  18. Acid-base chemistry of white wine: analytical characterisation and chemical modelling.

    Science.gov (United States)

    Prenesti, Enrico; Berto, Silvia; Toso, Simona; Daniele, Pier Giuseppe

    2012-01-01

    A chemical model of the acid-base properties is optimized for each white wine under study, together with the calculation of their ionic strength, taking into account the contributions of all significant ionic species (strong electrolytes and weak one sensitive to the chemical equilibria). Coupling the HPLC-IEC and HPLC-RP methods, we are able to quantify up to 12 carboxylic acids, the most relevant substances responsible of the acid-base equilibria of wine. The analytical concentration of carboxylic acids and of other acid-base active substances was used as input, with the total acidity, for the chemical modelling step of the study based on the contemporary treatment of overlapped protonation equilibria. New protonation constants were refined (L-lactic and succinic acids) with respect to our previous investigation on red wines. Attention was paid for mixed solvent (ethanol-water mixture), ionic strength, and temperature to ensure a thermodynamic level to the study. Validation of the chemical model optimized is achieved by way of conductometric measurements and using a synthetic "wine" especially adapted for testing.

  19. Elucidating the hard/soft acid/base principle: A perspective based on half-reactions

    International Nuclear Information System (INIS)

    Ayers, Paul W.; Parr, Robert G.; Pearson, Ralph G.

    2006-01-01

    A comprehensive analysis is presented for the acid-base double-exchange reaction as well as the associated acid-displacement and base-displacement 'half-reactions' with the goal of elucidating the meaning of the hard/soft acid/base (HSAB) principle and the conditions for its validity. When electron-transfer effects are important and other effects are negligible, the HSAB principle is driven by the surpassing stability of the soft acid/soft base product. When electrostatic effects dominate the reactivity, the HSAB principle is driven by the surpassing stability of the hard acid/hard base product. Because electron-transfer effects favor soft/soft interactions, while electrostatic effects favor hard/hard interactions, acid-base exchange reactions may be used to determine whether a reagent's reactivity is dominated by electron-transfer or by electrostatic effects. Because electron-transfer and electrostatic considerations separately favor the HSAB principle whenever the electronic chemical potentials of the acids and bases involved in the reaction are similar, our analysis provides strong support for the HSAB principle. The electronic chemical potential measures the intrinsic strength of acids and bases

  20. Biodegradation and Osteosarcoma Cell Cultivation on Poly(aspartic acid) Based Hydrogels.

    Science.gov (United States)

    Juriga, Dávid; Nagy, Krisztina; Jedlovszky-Hajdú, Angéla; Perczel-Kovách, Katalin; Chen, Yong Mei; Varga, Gábor; Zrínyi, Miklós

    2016-09-14

    Development of novel biodegradable and biocompatible scaffold materials with optimal characteristics is important for both preclinical and clinical applications. The aim of the present study was to analyze the biodegradability of poly(aspartic acid)-based hydrogels, and to test their usability as scaffolds for MG-63 osteoblast-like cells. Poly(aspartic acid) was fabricated from poly(succinimide) and hydrogels were prepared using natural amines as cross-linkers (diaminobutane and cystamine). Disulfide bridges were cleaved to thiol groups and the polymer backbone was further modified with RGD sequence. Biodegradability of the hydrogels was evaluated by experiments on the base of enzymes and cell culture medium. Poly(aspartic acid) hydrogels possessing only disulfide bridges as cross-links proved to be degradable by collagenase I. The MG-63 cells showed healthy, fibroblast-like morphology on the double cross-linked and RGD modified hydrogels. Thiolated poly(aspartic acid) based hydrogels provide ideal conditions for adhesion, survival, proliferation, and migration of osteoblast-like cells. The highest viability was found on the thiolated PASP gels while the RGD motif had influence on compacted cluster formation of the cells. These biodegradable and biocompatible poly(aspartic acid)-based hydrogels are promising scaffolds for cell cultivation.