692 research outputs found

    Premixed turbulent flame calculation

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    The importance of turbulent premixed flames in a variety of applications has led to a substantial amount of effort towards improving the understanding of these flames. Although these efforts have increased the understanding, many questions still remain. The use of direct numerical simulation (DNS) in solving these questions is examined

    Unique characterisation of Langerhans cells in the spleen of the African catfish (Clarias gariepinus)

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    The African catfish (Clarias gariepinus) has increasingly become an economically important food source especially in Africa, Asia and Europe, with exports extending to countries throughout the world. In the last 25 years, aquaculture of this species has been particularly effective with large increases in production and this is in part due to the catfish being highly resistant to disease. In order to further understand the immune system of the catfish, the spleen was investigated using a number of staining, immunohistochemical, light and transmission electron microscope techniques in order to verify the histological features of this organ. The gross histological features of the spleen confirmed the presence of a capsule containing numerous collagen fibers surrounded the spleen of the African catfish. Melanomacrophage centers, lymphocytes and surrounding arterial vessels were the main components of the white pulp whilst the red pulp contained sinusoids, capillaries and splenic cords of erythrocytes, macrophages and lymphocytes. Transmission electron microscopy identified Langerhans-like cells which were irregular to ovoid in shape with an electron lucent cytoplasm. The cells were characterized by the presence of numerous Birbeck-like granules, varying in shape from oval, round, rod to racket shaped granules. In total, three types of Birbeck-like granules were identified. The first type had heterogenic content, the second type were cored granules and the third type were racket shaped granules. Some of the racket shaped granules were enlarged and contained granular content. The Langerhans-like cells were further identified and characterised by showing a positive reaction with antibodies to S100 and CD1a. The existence of Langerhans-like cells within the spleen helps to identify the components of the immune system within the African catfish

    Flecainide Toxicity Resulting in Pacemaker Latency and Intermittent Failure to Capture

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    BACKGROUND Flecainide is a class Ic antiarrhythmic agent used in the treatment of supraventricular and ventricular arrhythmias. It is associated with a potent adverse effect profile; however, the effects of flecainide toxicity in the setting of a pacemaker have not been well described. We describe a unique case of flecainide toxicity secondary to acute kidney injury in the setting of a dual-chamber pacemaker, resulting in ventricular capture latency and intermittent failure to capture. CASE REPORT The patient was a 91-year-old female with a history of atrial fibrillation maintained in sinus rhythm on flecainide, who presented complaining of purple visual disturbances and syncope. She was found to be hypotensive and bradycardic, with a heart rate between 30 to 40 beats per minute. Lab work was notable for creatinine at 2.12 mg/dL. A 12-lead ECG demonstrated atrial and ventricular pacing with severely widened QRS complex and a significant latency between the pacemaker ventricular spike and the ventricular capture. The pacemaker was interrogated, revealing a significant increase in ventricular threshold from 0.75 V at 0.5 ms at baseline to 5.0 V at 1 ms to obtain consistent capture. After multiple boluses of IV sodium bicarbonate, the QRS acutely narrowed, latency interval improved, and consistent pacing capture was achieved. The flecainide level drawn on arrival was 3.09 mcg/mL. CONCLUSIONS Flecainide increases the ventricular capture threshold for pacemakers. Toxicity in these patients may present with pacemaker ventricular capture latency or failure to capture

    Varieties of Limited Access Orders: The nexus between politics and economics in hybrid regimes

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    This article advances our understanding of differences in hybrid stability by going beyond existing regime typologies that separate the study of political institutions from the study of economic institutions. It combines the work of Douglass North, John Wallis, and Barry Weingast (NWW) on varieties of social orders with the literature on political and economic regime typologies and dynamics to understand hybrid regimes as Limited Access Orders (LAOs) that differ in the way dominant elites limit access to political and economic resources. Based on a measurement of political and economic access applied to seven postā€Soviet states, the article identifies four types of LAOs. Challenging NWW's claim, it shows that hybrid regimes can combine different degrees of political and economic access to sustain stability. Our typology allows to form theoretical expectations about the kinds of political and/or economic changes that will move different types of LAOs toward more openness or closure

    Disease Control and Prevention

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    ā€” i ā€” Some thoughts about traumatic brain injury (TBI) dataā€¦ ā€¦People are uneducated about traumatic brain injury. They donā€™t recognize it when it happens to them or their loved ones; they donā€™t know the extent of the public health problemā€¦. This is my dream for people who will sustain a traumatic brain injury: ā€¦.At the time the TBI is diagnosed,ā€¦the injured person receives information about the consequences of traumatic brain injury and sources of education and support. ā€¦.All traumatic brain injuries will be counted, including mild TBIs. The Centers for Disease Control and Prevention will develop

    Ethnic In-Group Favoritism Among Minority and Majority Groups: Testing the Self-Esteem Hypothesis Among Preadolescents

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    The self-esteem hypothesis in intergroup relations, as proposed by social identity theory (SIT), states that successful intergroup discrimination enhances momentary collective self-esteem. This hypothesis is a source of continuing controversy. Furthermore, although SIT is increasingly used to account for childrenā€™s group attitudes, few studies have examined the hypothesis among children. In addition, the hypothesisā€™s generality makes it important to study among children from different ethnic groups. The present study, conducted among Dutch and Turkish preadolescents, examined momentary collective self-feelings as a consequence of ethnic group evaluations. The results tended to support the self-esteem hypothesis. In-group favoritism was found to have a self-enhancing effect among participants high in ethnic identification. This result was found for ethnic majority (Dutch) and minority (Turkish) participants.

    Morphology, adipocyte size, and fatty acid analysis of dairy cattle digital cushions, and the effect of body condition score and age

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    The digital cushion is an essential part of maintaining a healthy foot, working to dissipate foot strike and body weight forces and lameness from claw horn disruption lesions. Despite the importance of the digital cushion, little is known about the basic anatomy, adipocyte morphology, and fatty acid composition in relation to age, limb position, and body condition score. In total, 60 claws (from 17 cows) were selected and collected from a herd, ensuring that body condition score data and computed micro-tomography were known for each animal. Digital cushion tissue underwent histological staining combined with stereology, systematic random sampling, and cell morphology analysis, in addition to lipid extraction followed by fatty acid analysis. The results describe digital cushion architecture and adipocyte sizes. Adipocyte size was similar across all 4 claws (distal left lateral and medial and distal right lateral and medial) and across the ages (aged 2ā€“7 yr); however, animals with body condition score of 3.00 or more at slaughter had a significantly increased cell size in comparison to those with a score of less than 2.50. Of 37 fatty acid methyl esters identified, 5 differed between either the body condition score or different age groups. C10:0 capric acid, C14:0 myristic acid, C15:0 pentadecanoic acid, and C20:0 arachidic acid percentages were all lesser in lower body condition score cows, whereas C22:1n-9 erucic acid measurements were lesser in younger cows. Saturated fatty acid, monounsaturated fatty acid, and polyunsaturated fatty acid percentages were not altered in the different claws, ages, or body condition score groups. Triglyceride quantities did not differ for claw position or age but had decreased quantities in lower body condition score animals. Digital cushion anatomy, cellular morphology, and fatty acid composition have been described in general and also in animals with differing ages, body condition scores, and in the differing claws. Understanding fat deposition, mobilization, and composition are essential in not only understanding the roles that the digital cushion plays but also in preventing disorders and maintaining cattle health and welfare
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