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Sample records for 3he-mri study lacunarity

  1. {sup 3}He-MRI in follow-up of lung transplant recipients

    Energy Technology Data Exchange (ETDEWEB)

    Gast, Klaus Kurt; Zaporozhan, Julia; Ley, Sebastian; Biedermann, Alexander; Knitz, Frank; Eberle, Balthasar; Schmiedeskamp, Joerg; Heussel, Claus-Peter; Mayer, Eckhard; Schreiber, Wolfgang Guenter; Thelen, Manfred; Kauczor, Hans-Ulrich [Department of Radiology, Johannes Gutenberg University Hospital, Langenbeckstrasse 1, 55131, Mainz (Germany)

    2004-01-01

    The aim of this study was to evaluate the possible contribution of {sup 3}He-MRI to detect obliterative bronchiolitis (OB) in the follow-up of lung transplant recipients. Nine single- and double-lung transplanted patients were studied by an initial and a follow-up {sup 3}He-MRI study. Images were evaluated subjectively by estimation of ventilation defect area and quantitatively by individually adapted threshold segmentation and subsequent calculation of ventilated lung volume. Bronchiolitis obliterans syndrome (BOS) was diagnosed using pulmonary function tests. At {sup 3}He-MRI, OB was suspected if ventilated lung volume had decreased by 10% or more at the follow-up MRI study compared with the initial study. General accordance between pulmonary function testing and {sup 3}He-MRI was good, although subjective evaluation of {sup 3}He-MRI underestimated improvement in ventilation as obtained by pulmonary function tests. The {sup 3}He-MRI indicated OB in 6 cases. According to pulmonary function tests, BOS was diagnosed in 5 cases. All diagnoses of BOS were also detected by {sup 3}He-MRI. In 2 of these 5 cases, {sup 3}He-MRI indicated OB earlier than pulmonary function tests. The results support the hypothesis that {sup 3}He-MRI may be sensitive for early detection of OB and emphasize the need for larger prospective follow-up studies. (orig.)

  2. Hyperpolarised 3He MRI and 81mKr SPECT in chronic obstructive pulmonary disease

    International Nuclear Information System (INIS)

    During recent years, magnetic resonance imaging (MRI) using hyperpolarised (HP) 3He gas has emerged as a promising new method for the imaging of lung ventilation. However, systematic comparisons with nuclear medicine techniques have not yet been performed. The aim of this study was to compare ventilation imaging methods in 26 patients with chronic obstructive pulmonary disease (COPD) and nine lung healthy volunteers. HP 3He MRI, 81mKr single-photon emission computed tomography (SPECT), high-resolution computed tomography (HRCT) and pulmonary function tests were performed. The three scans were scored visually as percentage of non-ventilated/diseased lung, and a computer-based objective measure of the ventilated volume in HP 3He MRI and 81mKr SPECT and an emphysema index in HRCT were calculated. We found a good correlation between HP 3He MRI and 81mKr SPECT for both visual defect score (r=0.80, p81mKr SPECT (the score on HP 3He MRI was one-third less than that on 81mKr SPECT), but the difference was reduced after normalisation for different breathing depths (HP 3He MRI at total lung capacity; 81mKr SPECT at tidal breathing at functional residual capacity). HP 3He MRI provides detailed ventilation distribution images and defect scores are comparable on HP 3He MRI and 81mKr SPECT. Additionally, new insights into the regional pulmonary microstructure via the apparent diffusion coefficient measurements are provided by HP 3He MRI. HP 3He MRI is a promising new diagnostic tool for the assessment of ventilation distribution. (orig.)

  3. 3He-MRI of pulmonary ventilation: First clinical applications

    International Nuclear Information System (INIS)

    Purpose of the study is the visualisation of normal pulmonary ventilation in healthy volunteers and the evaluation of abnormalities in patients with different lung diseases using 3He magnetic resonance imaging (3He-MRI). Material und methods: Hyperpolarised 3He gas (V=300 ml, p=3x105 Pa, polarised to 35-45% by optical pumping, provided in special glass cells) was inhaled by eight healthy volunteers and ten patients with different lung diseases. A 3 D FLASH sequence (TR=11.8 ms; TE=5 ms; matrix 144x256, FOV 350 mm, section thickness 7-10 mm, coronal orientation) was performed in a single breath-hold (22-42 s). Clinical and radiological examinations were available for correlation. Results: The studies were successfully carried out in 8/8 volunteers and in 8/10 patients. The central airways were constantly visualised with intermediate to high signal instensity. The lung parenchyma of volunteers with normal ventilatory function showed rather homogeneous intermediate to high signal, whereas patients with chronic abstructive lung disease and/or pneumonia presented severe signal inhomogeneitises. Space-occupying lesions and pleural effusion caused large areas with little or no signal. The represented the lesion and adjacent ventilatory disturbances whose extent had not been presumed from chest X-ray or CT. The spatial resolution was higher than in ventilation scintigraphy. Conclusion: 3He MRI is a promising new modality for the assessment of pulmonary ventilation and its anormalies. (orig.)

  4. Oxygen-sensitive {sup 3}He-MRI in bronchiolitis obliterans after lung transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Gast, Klaus K. [Klinikum der Johannes Gutenberg-Universitaet, Klinik und Poliklinik fuer diagnostische und interventionelle Radiologie, Mainz (Germany); Biedermann, Alexander [Klinikum der Johannes Gutenberg-Universitaet, 3. Medizinische Klinik, Pulmonologie, Mainz (Germany); Herweling, Annette [Klinikum der Johannes Gutenberg-Universitaet, Klinik fuer Anaesthesiologie, Mainz (Germany); Schreiber, Wolfgang G. [Klinikum der Johannes Gutenberg-Universitaet, Klinik und Poliklinik fuer diagnostische und interventionelle Radiologie, MR-Physik, Mainz (Germany); Schmiedeskamp, Joerg [Max-Planck-Institut fuer Polymerforschung, Mainz (Germany); Mayer, Eckhard [Klinikum der Johannes Gutenberg-Universitaet, Klinik fuer Herz-, Thorax- und Gefaesschirurgie, Mainz (Germany); Heussel, Claus P. [Abteilung fuer Radiologie, Thoraxklinik Heidelberg, Heidelberg (Germany); Markstaller, Klaus; Eberle, Balthasar [Inselspital/Universitaetsspital, Klinik fuer Anaesthesiologie, Bern (Switzerland); Kauczor, Hans-Ulrich [Radiologie, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg (Germany)

    2008-03-15

    Oxygen-sensitive {sup 3}He-MRI was studied for the detection of differences in intrapulmonary oxygen partial pressure (pO{sub 2}) between patients with normal lung transplants and those with bronchiolitis obliterans syndrome (BOS). Using software developed in-house, oxygen-sensitive {sup 3}He-MRI datasets from patients with normal lung grafts (n = 8) and with BOS (n = 6) were evaluated quantitatively. Datasets were acquired on a 1.5-T system using a spoiled gradient echo pulse sequence. Underlying diseases were pulmonary emphysema (n = 10 datasets) and fibrosis (n = 4). BOS status was verified by pulmonary function tests. Additionally, {sup 3}He-MRI was assessed blindedly for ventilation defects. Median intrapulmonary pO{sub 2} in patients with normal lung grafts was 146 mbar compared with 108 mbar in patients with BOS. Homogeneity of pO2 distribution was greater in normal grafts (standard deviation pO2 34 versus 43 mbar). Median oxygen decrease rate during breath hold was higher in unaffected patients (-1.75 mbar/s versus -0.38 mbar/s). Normal grafts showed fewer ventilation defects (5% versus 28%, medians). Oxygen-sensitive {sup 3}He-MRI appears capable of demonstrating differences of intrapulmonary pO2 between normal lung grafts and grafts affected by BOS. Oxygen-sensitive {sup 3}He-MRI may add helpful regional information to other diagnostic techniques for the assessment and follow-up of lung transplant recipients. (orig.)

  5. Progression of emphysema in a 12-month hyperpolarized 3He-MRI study: lacunarity analysis provided a more sensitive measure than standard ADC analysis

    DEFF Research Database (Denmark)

    Diaz, Sandra; Casselbrant, Ingrid; Piitulainen, Eeva;

    2009-01-01

    subject was imaged at two lung volumes: functional residual capacity (FRC) and FRC plus 15% of total lung capacity. Means and standard deviations of apparent diffusion coefficients (ADCs) were calculated from coronal images of the entire lung and correlated with pulmonary function test results...

  6. Longitudinal assessment of treatment effects on pulmonary ventilation using 1H/3He MRI multivariate templates

    Science.gov (United States)

    Tustison, Nicholas J.; Contrella, Benjamin; Altes, Talissa A.; Avants, Brian B.; de Lange, Eduard E.; Mugler, John P.

    2013-03-01

    The utitlity of pulmonary functional imaging techniques, such as hyperpolarized 3He MRI, has encouraged their inclusion in research studies for longitudinal assessment of disease progression and the study of treatment effects. We present methodology for performing voxelwise statistical analysis of ventilation maps derived from hyper­ polarized 3He MRI which incorporates multivariate template construction using simultaneous acquisition of IH and 3He images. Additional processing steps include intensity normalization, bias correction, 4-D longitudinal segmentation, and generation of expected ventilation maps prior to voxelwise regression analysis. Analysis is demonstrated on a cohort of eight individuals with diagnosed cystic fibrosis (CF) undergoing treatment imaged five times every two weeks with a prescribed treatment schedule.

  7. Hyperpolarised {sup 3}He MRI and {sup 81m}Kr SPECT in chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Stavngaard, Trine [Copenhagen University Hospital, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet (Denmark); Copenhagen University Hospital, Danish Research Centre for Magnetic Resonance, Hvidovre (Denmark); Soegaard, Lise Vejby; Hanson, Lars G. [Copenhagen University Hospital, Danish Research Centre for Magnetic Resonance, Hvidovre (Denmark); Mortensen, Jann; Berthelsen, Anne Kiil [Copenhagen University Hospital, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet (Denmark); Schmiedeskamp, Joerg [Johannes Gutenberg Universitaet, Institut fuer Physik, Mainz (Germany); Dirksen, Asger [Gentofte University Hospital, Department of Respiratory Medicine, Hellerup (Denmark)

    2005-04-01

    During recent years, magnetic resonance imaging (MRI) using hyperpolarised (HP) {sup 3}He gas has emerged as a promising new method for the imaging of lung ventilation. However, systematic comparisons with nuclear medicine techniques have not yet been performed. The aim of this study was to compare ventilation imaging methods in 26 patients with chronic obstructive pulmonary disease (COPD) and nine lung healthy volunteers. HP {sup 3}He MRI, {sup 81m}Kr single-photon emission computed tomography (SPECT), high-resolution computed tomography (HRCT) and pulmonary function tests were performed. The three scans were scored visually as percentage of non-ventilated/diseased lung, and a computer-based objective measure of the ventilated volume in HP {sup 3}He MRI and {sup 81m}Kr SPECT and an emphysema index in HRCT were calculated. We found a good correlation between HP {sup 3}He MRI and {sup 81m}Kr SPECT for both visual defect score (r=0.80, p<0.0001) and objective estimate of ventilation (r=0.45, p=0.0157). In addition, both scans were well correlated with reference methods for the diagnosis of emphysema (pulmonary function test and HRCT). The defect scores were largest on {sup 81m}Kr SPECT (the score on HP {sup 3}He MRI was one-third less than that on {sup 81m}Kr SPECT), but the difference was reduced after normalisation for different breathing depths (HP {sup 3}He MRI at total lung capacity; {sup 81m}Kr SPECT at tidal breathing at functional residual capacity). HP {sup 3}He MRI provides detailed ventilation distribution images and defect scores are comparable on HP {sup 3}He MRI and {sup 81m}Kr SPECT. Additionally, new insights into the regional pulmonary microstructure via the apparent diffusion coefficient measurements are provided by HP {sup 3}He MRI. HP {sup 3}He MRI is a promising new diagnostic tool for the assessment of ventilation distribution. (orig.)

  8. Two-dimensional and three-dimensional oxygen mapping by 3He-MRI validation in a lung phantom

    International Nuclear Information System (INIS)

    The aim of this study was to validate oxygen-sensitive 3He-MRI in noninvasive determination of the regional, two- and three-dimensional distribution of oxygen partial pressure. In a gas-filled elastic silicon ventilation bag used as a lung phantom, oxygen sensitive two- and three-dimensional 3He-MRI measurements were performed at different oxygen concentrations which had been equilibrated in a range of normal and pathologic values. The oxygen partial pressure distribution was determined from 3He-MRI using newly developed software allowing for mapping of oxygen partial pressure. The reference bulk oxygen partial pressure inside the phantom was measured by conventional respiratory gas analysis. In two-dimensional measurements, image-based and gas-analysis results correlated with r=0.98; in three-dimensional measurements the between-methods correlation coefficient was r=0.89. The signal-to-noise ratio of three-dimensional measurements was about half of that of two-dimensional measurements and became critical (below 3) in some data sets. Oxygen-sensitive 3He-MRI allows for noninvasive determination of the two- and three-dimensional distribution of oxygen partial pressure in gas-filled airspaces. (orig.)

  9. Hyperpolarized 3He MRI and 81mKr SPECT in chronic obstructive pulmonary disease

    DEFF Research Database (Denmark)

    Stavngaard, Trine; Søgaard, Lise; Mortensen, J;

    2005-01-01

    was to compare ventilation imaging methods in 26 patients with chronic obstructive pulmonary disease (COPD) and nine lung healthy volunteers. METHODS: HP 3He MRI, 81mKr single-photon emission computed tomography (SPECT), high-resolution computed tomography (HRCT) and pulmonary function tests were performed....... The three scans were scored visually as percentage of non-ventilated/diseased lung, and a computer-based objective measure of the ventilated volume in HP 3He MRI and 81mKr SPECT and an emphysema index in HRCT were calculated. RESULTS: We found a good correlation between HP 3He MRI and 81mKr SPECT for both...... visual defect score (r=0.80, pKr SPECT (the score on HP 3He MRI...

  10. (3)He MRI in healthy volunteers: preliminary correlation with smoking history and lung volumes.

    Science.gov (United States)

    Guenther, D; Eberle, B; Hast, J; Lill, J; Markstaller, K; Puderbach, M; Schreiber, W G; Hanisch, G; Heussel, C P; Surkau, R; Grossmann, T; Weiler, N; Thelen, M; Kauczor, H U

    2000-06-01

    MRI with hyperpolarized helium-3 ((3)He) provides high-resolution imaging of ventilated airspaces. The first aim of this (3)He-study was to compare observations of localized signal defects in healthy smokers and non-smokers. A second aim was to describe relationships between parameters of lung function, volume of inspired (3)He and signal-to-noise ratio. With Ethics Committee approval and informed consent, 12 healthy volunteers (seven smokers and five non-smokers) were studied. Imaging was performed in a 1.5 T scanner using a two-dimensional FLASH sequence at 30V transmitter amplitude (TR/TE/alpha = 11 ms/4.2 ms/microprocessor-controlled delivery device and imaged during single breath-holds. Images were evaluated visually, and scored using a prospectively defined 'defect-index'. Signal-to-noise ratio of the images were correlated with localization, (3)He volumes and static lung volumes. Due to poor image quality studies of two smokers were not eligible for the evaluation. Smokers differed from non-smokers in total number and size of defects: the 'defect-index' of smokers ranged between 0.8 and 6.0 (median = 1.1), that of non-smokers between 0.1 and 0.8 (median = 0.4). Intraindividually, an anteroposterior gradient of signal-to-noise ratio was apparent. Signal-to-noise ratio correlated with the estimated amount of hyperpolarization administered (r = 0. 77), but not with static lung volumes. We conclude that (3)He MRI is a sensitive measure to detect regional abnormalities in the distribution of ventilation in clinically healthy persons with normal pulmonary function tests.

  11. Improved Technique for Measurement of Regional Fractional Ventilation by Hyperpolarized 3He MRI

    OpenAIRE

    Emami, Kiarash; Kadlecek, Stephen J.; Woodburn, John M.; Zhu, Jianliang; Yu, Jiangsheng; Vahdat, Vahid; Pickup, Stephen; Ishii, Masaru; Rizi, Rahim R.

    2010-01-01

    Quantitative measurement of regional lung ventilation is of great significance in assessment of lung function in many obstructive and restrictive pulmonary diseases. A new technique for regional measurement of fractional ventilation using hyperpolarized 3He MRI is proposed, addressing the shortcomings of an earlier approach that limited its use to small animals. The new approach allows for the acquisition of similar quantitative maps over a shortened period and requires substantially less 3He...

  12. Simultaneous measurement of pulmonary partial pressure of oxygen and apparent diffusion coefficient by hyperpolarized 3He MRI

    OpenAIRE

    Yu, Jiangsheng; Law, Michelle; Kadlecek, Stephen; Emami, Kiarash; Ishii, Masaru; Stephen, Michael; Woodburn, John M.; Vahdat, Vahid; Rizi, Rahim R.

    2009-01-01

    Hyperpolarized 3He (HP 3He) MRI shows promise to assess structural and functional pulmonary parameters in a sensitive, regional and non-invasive way. Structural HP 3He MRI has applied the apparent diffusion coefficient (ADC) for the detection of disease-induced lung microstructure changes at the alveolar level, and HP 3He pulmonary partial pressure of oxygen (pO2) imaging measures the oxygen transfer efficiency between the lung and blood stream. Although both parameters are affected in chroni...

  13. Validity of apparent diffusion coefficient hyperpolarized 3He-MRI using MSCT and pulmonary function tests as references

    DEFF Research Database (Denmark)

    Diaz, Sandra; Casselbrant, Ingrid; Piitulainen, Eeva;

    2008-01-01

    . Correlations between mean ADC and EI and 15th percentile were both r=0.90 and for MLD r=0.59. There was higher correlation between mean ADC and %predicted DLCO (r=0.90) than between EI and %predicted DLCO (r=0.76). CONCLUSION: HP (3)He-MRI correlates well with density measurements from MSCT and agrees better...

  14. A software tool for analysis and quantification of regional pulmonary ventilation using dynamic hyperpolarised-3He-MRI

    International Nuclear Information System (INIS)

    Purpose: 3He-MRI is able to visualize the regional distribution of lung ventilation with a temporal and spatial resolution so far unmatched by any other technique. The main of the study was the development of a new software tool for quantification of dynamic ventilation parameters in absolute physical units. Materials and Methods: During continuous breathing, a bolus of hyperpolarized 3He (300 ml) was applied at inspiration and a series of 168 coronal projection images simultaneously acquired using a 2D FLASH-sequence. Postprocessing software was developed to analyze the 3He distribution in the lung. After correction for lung motion, several ventilation parameters (rise time, delay time, 3He amount and 3He peak flow) were calculated. Due to normalization of signal intensities, these parameters are presented in absolute physical units. The data sets were analyzed on a ROI basis as well as on a pixel-by-pixel basis. Results: Using the developed software, the measurements were analyzed in 6 lung-healthy volunteers, in one patient after lung transplantation, and in one patient with lung emphysema. The volunteers' parameter maps of the pixel-based analysis showed an almost homogeneous distribution of the ventilation parameters within the lung. In the parameter maps of both patients, regions with poor ventilation were observed. Conclusion: The developed software permits an objective and quantitative analysis of regional lung ventilation in absolute physical units. The clinical significance of the parameters, however, has to be determined in larger clinical studies. The software may become valuable in grading and following pulmonary function as well as in monitoring any therapy. (orig.)

  15. Functional {sup 3}He-MRI of the lungs; Funktionelle {sup 3}He-MRT der Lunge

    Energy Technology Data Exchange (ETDEWEB)

    Gast, K.K.; Wolf, U. [Universitaetsmedizin der Johannes-Gutenberg-Universitaet Mainz, Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie, Mainz (Germany)

    2009-08-15

    Pulmonary diseases have a high health-related and economic significance. {sup 3}He-MRI is an alternative imaging method which can detect ventilatory disturbances with a high sensitivity. The application of different pulse sequences allows static and dynamic assessment of ventilation and bronchial gas flow, non-invasive measurement of intrapulmonary oxygen partial pressure and quantification of pulmonary parenchyma destruction and overinflation. Generally, the method is applicable for obstructive and restrictive ventilatory disturbances but initial approaches also exist for vascular pulmonary diseases. Specific clinical applications remain to be determined but {sup 3}He-MRI is an excellent instrument for the assessment of physiologic and pathophysiologic interrelations in the distribution of ventilation. (orig.) [German] Lungenerkrankungen haben einen hohen gesundheitlichen und volkswirtschaftlichen Stellenwert. Die {sup 3}He-MRT ist eine alternative bildgebende Methode, die sensitiv Ventilationsstoerungen nachweisen kann. Ueber unterschiedliche Pulssequenzen koennen Ventilation und Gasfluesse statisch und dynamisch dargestellt, der intrapulmonale Sauerstoffpartialdruck nichtinvasiv gemessen und die Destruktion und Ueberblaehung des Lungenparenchyms quantifiziert werden. Prinzipiell ist die Methode fuer die Untersuchung obstruktiver und restriktiver Ventilationsstoerungen anwendbar, Ansaetze existieren jedoch auch fuer vaskulaere Lungenerkrankungen. Spezifische klinische Anwendungen fuer die {sup 3}He-MRT muessen noch erarbeitet werden, sie ist jedoch ein hervorragendes Instrument zur Untersuchung physiologischer und pathophysiologischer Zusammenhaenge bei der Ventilationsverteilung. (orig.)

  16. Hyperpolarised 3He MRI versus HRCT in COPD and normal volunteers: PHIL trial

    DEFF Research Database (Denmark)

    van Beek, E J R; Dahmen, A M; Stavngaard, T;

    2009-01-01

    ) and age-matched never-smokers. All diagnostic studies were completed in 94 subjects (52 with COPD; 13 with alpha(1)-ATD; 29 healthy subjects; 63 males; and 31 females; median age 62 yrs). The consensus assessment of radiologists, blinded for other test results, estimated nonventilated lung volume (HP...

  17. Emphysematous changes and normal variation in smokers and COPD patients using diffusion 3He MRI

    International Nuclear Information System (INIS)

    Introduction: This study aims to quantify global and regional changes of diffusive motion of 3He gas within the lung, as determined by hyperpolarized 3He MR apparent diffusion coefficient (ADC) measurement, in non-smokers, smokers and chronic obstructive pulmonary disease (COPD) patients. Methods: Age-matched groups of six healthy non-smokers, five healthy smokers and five patients with COPD. The experiments were performed with approval from the local Research Ethics Committee. Diffusion imaging was performed following hyperpolarized 3He gas inhalation, producing ADC maps. Mean and standard deviation of the ADCs were used to compare the subject groups and assess regional variations within individuals. Results: The intra-individual standard deviation of ADC in the healthy smokers was significantly larger than that of the non-smoking group (P < 0.02). Compared to the non-smoking group, COPD patients had significantly higher mean and standard deviation of ADC (P < 0.01). The mean ADC in the anterior half of the chest was systematically higher than in the posterior half in the healthy non-smoking subject group. Discussion: This study suggests that there are regional trends in the ADC values of healthy volunteers that may have implications for the clinical interpretation of ADC values. Less homogeneous ADC values have been detected in asymptomatic smokers, indicative of damage to the distal air spaces

  18. Analysis of acute ischemic stroke presenting classic lacunar syndrome. A study by diffusion-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Terai, Satoshi; Ota, Kazuki; Tamaki, Kinya [Hakujyuji Hospital, Fukuoka (Japan)

    2002-03-01

    We retrospectively assessed the pathophysiological features of acute ischemic stroke presenting ''classic'' lacunar syndrome by using diffusion-weighted imaging (DWI). Subjects were 16 patients who were admitted to our hospital within 24 hours of stroke onset and underwent DWI examination on admission. These were divided into three categorical groups; pure motor hemiplegia (PMH) in 8, sensorimotor stroke (SMS) in 7, and dysarthria-clumsy hand syndrome (DCHS) in 1. The fresh responsible lesions were identified by DWI in the perforating territory in 7 patients with PMH and 7 with SMS. Four (one had two possible response lesions; pons and corona radiata) and five patients in the respective groups were diagnosed as lacunar infarction on admission (the largest dimension of the lesion measuring smaller than 15 mm). On the contralateral side to the neurological symptoms, DWI revealed high intensities in cortex, subcortical white matter, and anterior and posterior border zones in the remaining one patient with PMH and in the precentral arterial region in one with DCHS. They were diagnosed as atherothrombotic infarction resulting from the occlusion of the internal carotid artery and cerebral embolism due to atrial fibrillation, respectively. Three patients with PMH showed progressive deterioration after admission and follow-up DWI study in an acute stage revealed enlargement of heir ischemic lesions. The present study suggests that DWI is a useful imaging technique for diagnosis of clinical categories and observation for pathophsiological alteration in the acute ischemic stroke patients with ''classic'' lacunar syndrome. Our results also indicate a necessity to be aware that various types of fresh ischemic lesions other than a single lacune might possibly be developing in cases with this syndrome. (author)

  19. A comparative study of symptoms in multiple lacunar state and MRI findings

    International Nuclear Information System (INIS)

    A multiple lacunar state is considered to cause gait disturbance, pseudobulbar palsy, or silent stroke. In the present study, these symptoms is multiple lacunar state and the incidences of abnormal findings on magnetic resonance imaging (MRI) were investigated comparatively. Thirty-eight patients (23 males and 15 females; average age 73.6 y.o.) with ischemic cerebral lesions on T2 weighted images of MRI were studied. In the group with gait disturbance only, the incidences of widening of the ventricular system and periventricular hyperintensity (PVH) around the frontal horn were significantly high compared with the group with silent stroke (p<0.01, p<0.005; respectively), and hyperintensity area of the semioval center were demonstrated prominently in the regions perfused by anterior cerebral artery. In the group with pseudobulbar palsy only, the incidences of PVH around the posterior part of the lateral ventricle and hyperintensity area of the basal ganglion region were significantly high as compared with the group with silent stroke (p<0.01, p<0.05; respectively), and hyperintensity area of the semioval center were demonstrated prominently in the regions perfused by middle cerebral artery. (author)

  20. Clinical study on magnetic resonance imaging of lacunar infarcts and cerebrovascular high-risk group

    Energy Technology Data Exchange (ETDEWEB)

    Hironaka, Masatoshi (Hiroshima Univ. (Japan). School of Medicine)

    1990-04-01

    Magnetic resonance imaging (MRI) study was performed in 32 patients with recent lacunar stroke. T2-weighted images showed ischemic lesions more clearly than T1-weighted images. Sixty-six percent of 32 patients had periventricular lesions. Eighty-four percent had subcortical white matter lesions. Sixty-nine percent had lesions in basal ganglia. Twenty-eight percent had lesions in brainstem. Periventricular lesions were revealed symmetrically. On the other hand, lesions in other areas were not detected symmetrically. Severe periventricular lesions on MRI were similar to those of Binswanger's disease. Patients with severe periventricular lesions had often hypertension. Moreover, two of them had dementia. Twenty-three patients with transient ischemic attack had less remarkable lesions than patients with lacunar stroke. Thirty-seven patients with a history of cerebrovascular risk factors (hypertension, diabetes mellitus) had severer lesions compared with normal controls. Sixty-one percent of controls, who had no cerebrovascular symptoms and signs, had MRI lesions. These results suggest that MRI is useful for detection of cerebral ischemic lesions with no associated clinical symptoms or signs. (author).

  1. Clinical study on magnetic resonance imaging of lacunar infarcts and cerebrovascular high-risk group

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) study was performed in 32 patients with recent lacunar stroke. T2-weighted images showed ischemic lesions more clearly than T1-weighted images. Sixty-six percent of 32 patients had periventricular lesions. Eighty-four percent had subcortical white matter lesions. Sixty-nine percent had lesions in basal ganglia. Twenty-eight percent had lesions in brainstem. Periventricular lesions were revealed symmetrically. On the other hand, lesions in other areas were not detected symmetrically. Severe periventricular lesions on MRI were similar to those of Binswanger's disease. Patients with severe periventricular lesions had often hypertension. Moreover, two of them had dementia. Twenty-three patients with transient ischemic attack had less remarkable lesions than patients with lacunar stroke. Thirty-seven patients with a history of cerebrovascular risk factors (hypertension, diabetes mellitus) had severer lesions compared with normal controls. Sixty-one percent of controls, who had no cerebrovascular symptoms and signs, had MRI lesions. These results suggest that MRI is useful for detection of cerebral ischemic lesions with no associated clinical symptoms or signs. (author)

  2. Dynamic cerebral autoregulation and cerebrovascular reactivity: a comparative study in lacunar infarct patients

    International Nuclear Information System (INIS)

    The major purpose of this study was to simultaneously evaluate dCA before and shortly after cerebral vasodilatation evoked by infusion of acetazolamide (ACZ). It was questioned if and to what degree dCA was changed after ACZ infusion. Using 15 mg kg−1 ACZ infusion cerebrovascular reactivity (CVR) was assessed in 29 first ever lacunar stroke patients (19 M/10 F). During the CVR-test, the electrocardiogram, non-invasive finger arterial blood pressure (ABP) and middle cerebral artery blood flow velocity (CBFV) were recorded. DCA based on spontaneous blood pressure variations was evaluated in 24 subjects by linear transfer function analysis. Squared coherence, gain and phase angle in the frequency range of autoregulation (0.04–0.16 Hz) were compared before and after ACZ infusion. After ACZ infusion, median phase angle decreased significantly (p < 0.005 Wilcoxon) to 0.77 rad compared to a pre-test baseline value of 1.05 rad, indicating less efficient dCA due to ACZ. However, post-test phase values are still mostly within the normal range. Poor and statistically non-significant correlations were found between CVR and absolute dCA phase angle. It can be concluded that CVR testing with body weight adjusted infusion of ACZ lowers dCA performance but by no means exhausts dCA, suggesting that in this way maximal CVR is not determined. Characterizing dCA based on transfer function analysis of ABP to CBFV needs no provocation and adverse patient effects are minimal. The poor correlation between CVR and dCA phase angle supports an interpretation that CVR and dCA study different mechanisms of cerebrovascular control

  3. Models and Applications of in Vivo Lung Morphometry with Hyperpolarized 3He MRI in a Mild COPD Population

    Science.gov (United States)

    Quirk, James D.; Sukstanskii, Alexander L.; Gierada, David S.; Woods, Jason C.; Conradi, Mark S.; Yablonskiy, Dmitriy A.

    2008-12-01

    Hyperpolarized 3He diffusion MRI is increasingly used to non-invasively quantify local alveolar structure changes, such as those from Chronic Obstructive Pulmonary Disease (COPD). Previously, we described an in vivo lung morphometry technique that decouples the helium apparent diffusion coefficient (ADC) into components oriented along the longitudinal (DL) and transverse (DT) axes of the acinar airways. Herein, we discuss our recent expansion of this theory, which relates the anisotropy of the MRI diffusion signal to the geometrical parameters of the acinar airways. We demonstrate the utility of this model in human studies and compare the measured airway radii with prior ex vivo experiments.

  4. Multifractal modelling and 3D lacunarity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hanen, Akkari, E-mail: bettaieb.hanen@topnet.t [Laboratoire de biophysique, TIM, Faculte de Medecine (Tunisia); Imen, Bhouri, E-mail: bhouri_imen@yahoo.f [Unite de recherche ondelettes et multifractals, Faculte des sciences (Tunisia); Asma, Ben Abdallah, E-mail: asma.babdallah@cristal.rnu.t [Laboratoire de biophysique, TIM, Faculte de Medecine (Tunisia); Patrick, Dubois, E-mail: pdubois@chru-lille.f [INSERM, U 703, Lille (France); Hedi, Bedoui Mohamed, E-mail: medhedi.bedoui@fmm.rnu.t [Laboratoire de biophysique, TIM, Faculte de Medecine (Tunisia)

    2009-09-28

    This study presents a comparative evaluation of lacunarity of 3D grey level models with different types of inhomogeneity. A new method based on the 'Relative Differential Box Counting' was developed to estimate the lacunarity features of grey level volumes. To validate our method, we generated a set of 3D grey level multifractal models with random, anisotropic and hierarchical properties. Our method gives a lacunarity measurement correlated with the theoretical one and allows a better model classification compared with a classical approach.

  5. Vitamin B12 and Progression of White Matter Lesions. A 2-Year Follow-Up Study in First-Ever Lacunar Stroke Patients

    OpenAIRE

    van Overbeek, Ellen C.; Staals, Julie; van Oostenbrugge, Robert J.

    2013-01-01

    In cross-sectional studies periventricular white matter lesions (WML) were related to low plasma levels of vitamin B12. Whether low vitamin B12 levels are also related to progression of WML is still unknown. We studied baseline vitamin B12 levels and its association with progression of WML over 2 years of follow-up in first-ever lacunar stroke patients. In 107 first-ever lacunar stroke patients in whom baseline brain MRI and vitamin B12 status were available, we obtained a follow-up brain MRI...

  6. Development and application of methods to quantify spatial and temporal hyperpolarized 3He MRI ventilation dynamics: preliminary results in chronic obstructive pulmonary disease

    Science.gov (United States)

    Kirby, Miranda; Wheatley, Andrew; McCormack, David G.; Parraga, Grace

    2010-03-01

    Hyperpolarized helium-3 (3He) magnetic resonance imaging (MRI) has emerged as a non-invasive research method for quantifying lung structural and functional changes, enabling direct visualization in vivo at high spatial and temporal resolution. Here we described the development of methods for quantifying ventilation dynamics in response to salbutamol in Chronic Obstructive Pulmonary Disease (COPD). Whole body 3.0 Tesla Excite 12.0 MRI system was used to obtain multi-slice coronal images acquired immediately after subjects inhaled hyperpolarized 3He gas. Ventilated volume (VV), ventilation defect volume (VDV) and thoracic cavity volume (TCV) were recorded following segmentation of 3He and 1H images respectively, and used to calculate percent ventilated volume (PVV) and ventilation defect percent (VDP). Manual segmentation and Otsu thresholding were significantly correlated for VV (r=.82, p=.001), VDV (r=.87 p=.0002), PVV (r=.85, p=.0005), and VDP (r=.85, p=.0005). The level of agreement between these segmentation methods was also evaluated using Bland-Altman analysis and this showed that manual segmentation was consistently higher for VV (Mean=.22 L, SD=.05) and consistently lower for VDV (Mean=-.13, SD=.05) measurements than Otsu thresholding. To automate the quantification of newly ventilated pixels (NVp) post-bronchodilator, we used translation, rotation, and scaling transformations to register pre-and post-salbutamol images. There was a significant correlation between NVp and VDV (r=-.94 p=.005) and between percent newly ventilated pixels (PNVp) and VDP (r=- .89, p=.02), but not for VV or PVV. Evaluation of 3He MRI ventilation dynamics using Otsu thresholding and landmark-based image registration provides a way to regionally quantify functional changes in COPD subjects after treatment with beta-agonist bronchodilators, a common COPD and asthma therapy.

  7. A software program for quantitative analysis of alveolar oxygen partial pressure (pAO2) with oxygen-sensitive 3He-MRI

    International Nuclear Information System (INIS)

    Purpose: To develop a software tool for quantitative analysis of alveolar oxygen partial pressure (pAO2) as well as its time course during apnea. Material and Methods: T1-relaxation times of hyperpolarized 3He are reduced by paramagnetic oxygen rendering 3He-MRI sensitive to oxygen and thus allowing the assessment of the local oxygen partial pressure in the pulmonary airspaces. Oxygen-related relaxation and loss of polarization by RF-excitation can be discriminated by acquiring two image series with varying interscan delay and/or flip angles. Software was developed to calculate the pAO2 and the decay rate in user-defined regions of interest (ROIs) automatically. Moreover, parameter maps can be calculated. In addition to the analysis of 2-dimensional data sets, the software allows the evaluation of 3-dimensional measurements for the first time. Artifacts due to lung motion were reduced by implementing a motion correction algorithm. Results: The software was successfully applied to data sets from healthy volunteers and from patients with various lung diseases. The parameter maps demonstrated a more homogeneous distribution of pAO2 for the volunteers than for the patients. A regional increase in pAO2 was found in a few patients. Conclusion: the described software allows the absolute quantification of pAO2 as well as its variation over time. In the future therefore, the software may gain importance for detecting mis-matches between ventilation and perfusion, e.g., in patients with pulmonary embolism or chronic obstructive lung diseases. (orig.)

  8. Osteocyte lacunar properties in rat cortical bone

    DEFF Research Database (Denmark)

    Bach-Gansmo, Fiona Linnea; Weaver, James C.; Jensen, Mads Hartmann;

    2015-01-01

    Recently, the roles of osteocytes in bone maintenance have gained increasing attention. Osteocytes reside in lacunae that are interconnected by canaliculi resulting in a vast cellular network within the mineralized bone matrix. As the structure of the lacuno-canalicular network is highly connected......-species but also inter-site variation in lacunar properties. Here, osteocyte lacunae in rat cortical bone have been studied using synchrotron radiation micro computed tomography (SR μCT) and backscattered electron (BE) microscopy. Quantitative lacunar geometric characteristics are reported based on the synchrotron...... radiation data, differentiating between circumferential lamellar bone and a central, more disordered bone type. From these studies, no significant differences were found in lacunar volumes between lamellar and central bone, whereas significant differences in lacunar orientation, shape and density values...

  9. Fractal dimension and lacunarity analysis of mammographic patterns in assessing breast cancer risk related to HRT treated population: a longitudinal and cross-sectional study

    Science.gov (United States)

    Karemore, Gopal; Nielsen, Mads

    2009-02-01

    Structural texture measures are used to address the aspect of breast cancer risk assessment in screening mammograms. The current study investigates whether texture properties characterized by local Fractal Dimension (FD) and Lacunarity contribute to asses breast cancer risk. FD represents the complexity while the Lacunarity characterize the gappiness of a fractal. Our cross-sectional case-control study includes mammograms of 50 patients diagnosed with breast cancer in the subsequent 2-4 years and 50 matched controls. The longitudinal double blind placebo controlled HRT study includes 39 placebo and 36 HRT treated volunteers for two years. ROIs with same dimension (250*150 pixels) were created behind the nipple region on these radiographs. Box counting method was used to calculate the fractal dimension (FD) and the Lacunarity. Paired t-test and Pearson correlation coefficient were calculated. It was found that there were no differences between cancer and control group for FD (P=0.8) and Lacunarity (P=0.8) in crosssectional study whereas earlier published heterogeneity examination of radiographs (BC-HER) breast cancer risk score separated groups (p=0.002). In the longitudinal study, FD decreased significantly (Pbreast cancer risk, nor show good sensitivity to HRT.

  10. Lacunar fractal photon sieves

    OpenAIRE

    Gimenez, Fernando; Furlan, Walter D.; Monsoriu, Juan A.

    2007-01-01

    We present a new family of diffractive lenses whose structure is based on the combination of two concepts: photon sieve and fractal zone plates with variable lacunarity. The focusing properties of different members of this family are examined. It is shown that the sieves provide a smoothing effect on the higher order foci of a conventional lacunar fractal zone plate. However, the characteristic self-similar axial response of the fractal zone plates is always preserved.

  11. Physical and structural studies of chemical Vapor deposited lacunar neodymium manganite thin films

    Directory of Open Access Journals (Sweden)

    Oumezzine M.

    2012-06-01

    Full Text Available Lacunar Nd1-xMnO3-δ thin films were successfully deposited by a liquid source metal-organic MOCVD technique on (001 SrTiO3 (STO, LaAlO3 (LAO and Si substrates. Optimal growth conditions are reported. TEM and X-ray diffraction characterisations reveal that the thin films grown on STO and LAO substrates are single crystalline layers epitaxially grown on the top of the substrates. The relationship between the crystallographic orientation of the films and those of the substrates were determined. Magnetic transition temperatures (Tc of the as-grown STO films, deduced from Squid Magnetometer measurements, are compared to the corresponding bulk values (typically 100K. Our magnetic measurements also suggest a complicated magnetic behavior close to the one observed in bulk samples: magnetization curves obtained under different applied magnetic fields indicate a possible reverse of the magnetization sign at low temperatures.

  12. Clinical evaluation of β-TCP in the treatment of lacunar bone defects: A prospective, randomized controlled study

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhen; Guo, Zheng [Department of Orthopaedics, Xijing hospital, Fourth Military Medical University, Xi' an 710032 (China); Bai, Hua [Department of Toxicology, Faculty of Preventive Medicine, Fourth Military Medical University, Xi' an 710032 (China); Li, Jing; Li, Xiangdong [Department of Orthopaedics, Xijing hospital, Fourth Military Medical University, Xi' an 710032 (China); Chen, Guojing, E-mail: guojing_chen@sohu.com [Department of Orthopaedics, Xijing hospital, Fourth Military Medical University, Xi' an 710032 (China); Lu, Jianxi [Department of Orthopaedics, Shanghai Ninth People' s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 710048 (China)

    2013-05-01

    The aim of this study was to investigate the potential wide application of beta tricalcium phosphate (β-TCP) only for bone defects as compared to allograft. 95 patients with a solitary bone cyst were randomly assigned to the treatment. A new radiographic scoring system was employed to calculate the biodegradation of bone graft and to evaluate the influence of multiple factors. At an average of 28.43 months after surgery, a radiographic semi-quantitative analysis revealed that the degradation rates of β-TCP and the allograft were comparable (p > 0.05). Age, complication, packing methods and granule diameters have a significant influence on β-TCP degradation. The loose packing method and 3–5 mm granule size should be employed in clinical practice. A histological analysis of biopsy showed that β-TCP supported the growth of fibrous tissue, vascular tissue, as well as bone tissue into the implants. The results proved that single β-TCP is an advantageous alternative to allografts for lacunar bone defect repair and would well guide the design and clinical application of the β-TCP. - Highlights: ► Single beta-TCP was used only for bone defect as compared to allograft. ► Beta-TCP shows similar performance as allografts in degradation rates. ► Age, complication, packing methods and granules diameters influence beta-TCP degradation. ► Loose packing method should be employed in clinical practice. ► The degradation of the beta-TCP tends to be better in young patients.

  13. MRI findings on lacunar infarction with no clinical symptoms

    International Nuclear Information System (INIS)

    The purpose of this study was to examine how lacunar infarction developed and what its characteristics were. As this disease had little noticeable clinical symptoms and is likely to draw less attention than other types of cerebrovascular diseases like panhemispheric infarction, it's difficult to make an early diagnosis of it or treat it successfully. The subjects in this study were 196 people who showed no clinical symptoms and took a MRI test. When the MRI test data were analyzed, signal intensity and the part where that disease was detected were primarily taken into account. As a result, it's found that 116 people had no lacunar infarction and 80 people suffered from that disease, including 13 with very mild lacunar infarction, 41 with mild lacunar infarction and 26 with lacunar infarction. However, very mild and mild lacunar infarction could not be viewed as clinically significant cases, and only 26 people, which accounted for 13 percent of the subjects, should be considered to be diagnosed with lacunar infarction. The most common part where that disease was found was white matter and basal ganglia, regardless of gender. Accordingly, those who are exposed to health hazards such as hypertension or diabetes should take a MRI test to prevent cerebrovascular diseases that might be caused by those illnesses

  14. MRI findings on lacunar infarction with no clinical symptoms

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ham Gyum [Ansan College, Ansan (Korea, Republic of)

    2003-12-15

    The purpose of this study was to examine how lacunar infarction developed and what its characteristics were. As this disease had little noticeable clinical symptoms and is likely to draw less attention than other types of cerebrovascular diseases like panhemispheric infarction, it's difficult to make an early diagnosis of it or treat it successfully. The subjects in this study were 196 people who showed no clinical symptoms and took a MRI test. When the MRI test data were analyzed, signal intensity and the part where that disease was detected were primarily taken into account. As a result, it's found that 116 people had no lacunar infarction and 80 people suffered from that disease, including 13 with very mild lacunar infarction, 41 with mild lacunar infarction and 26 with lacunar infarction. However, very mild and mild lacunar infarction could not be viewed as clinically significant cases, and only 26 people, which accounted for 13 percent of the subjects, should be considered to be diagnosed with lacunar infarction. The most common part where that disease was found was white matter and basal ganglia, regardless of gender. Accordingly, those who are exposed to health hazards such as hypertension or diabetes should take a MRI test to prevent cerebrovascular diseases that might be caused by those illnesses.

  15. Correlative factors of cognitive impairment in patients with lacunar infarcts

    Institute of Scientific and Technical Information of China (English)

    Zhang Qiujuan; Yao Xiaoxin; Guo Youmin; Zhang Gejuan; Yang Junle

    2007-01-01

    Objective To study the relationships between cognitive impairment in patients with lacunar infarcts and quantitative CT measures and to determine the independent correlative factors of cognitive impairment. Methods Neuropsychological examination was conducted for 128 patients with acute lacunar infarct. Number, location, and volume of infarcts, cerebral atrophy index and severity of white matter lesions (WMLs) were measured and recorded. Results The number of lacunar infarcts in cognitive impairment (CI) group was significantly larger than that in cognitive normal (CN) group. Mean width of sulcus and sylvian fissure, index of frontal horn and ventricular-brain ratio (VBR) were significantly different in both groups. There were more patients with 3 grades or 4 grades WMLs in CI group (62%) than those in CN group (22%). The total volume of lacunar infarcts showed no statistically significant difference. Logistic regression analysis indicated that the number of lacunar infarcts in frontal subcortex and thalamus, the volume of infarcts in anterior periventricular white matter, width of cerebral sulcus and sylvian fissure were correlated with cognitive impairment respectively. Additionally, age and education were correlative factors of cognitive impairment in patients with lacunar infarct. Conclusion Correlative factors of cognitive impairment in patients with lacunar infarct are not merely one feature, but a combination of infarct features (number, location, and volume), cortical atrophy and host factors (age and education).

  16. Enlarged perivascular spaces and lacunar infarction Cerebral magnetic resonance evaluation

    Institute of Scientific and Technical Information of China (English)

    Weihong Yan; Jing Fang; Cuijuan Zhou

    2008-01-01

    BACKGROUND:Previous studies have demonstrated that enlarged perivascular spaces(EPVS)arg a result of microvaseular disease.To date,there age few reports about the relationship between EPVS and lacunar infarction.OBJECTIVE:To investigate whether EPVS is associated with lacunar infarction on the basis of cerebral magnetic resonance(MR)examination,clinical symptoms and signs,and past medical history of patients.DESIGN,TIME AND SETTING:Case contrast analysis was performed at the Department of Neurology,Shanghai Ninth People's Hospital from January 2007 to January 2008.PARTICIPANTS:Sixty-eight patients with lacunar infarction were admired to the Department of Neurology of Shanghai Ninth People's Hospital,including 37 cases with first-ever infarction,and 31 with infarction recurrence.In addition,53 healthy people were selected as controls.METHODS:All participants underwent past medical history investigation,nervous system examination.and cranial MR.The subjects were assessed using the JMW rating scale to identify the EPVS grade.MAIN OUTCOME MEASURES:EPVS scores of patients and controls;risk factors for cerebral vascular disease in patients with first-ever or recurrence of lacunar infarction.RESULTS:The EPVS grade from lacunar infarction patients was significantly higher than of the control group(P<0.05).The EPVS grade in patients with recurring lacunar infarction was significantly higher than in patients with first-ever infarction(P<0.05).In addition,hypertension incidence in patients with recurring lacunar infarction was significantly higher than in patients wim first-ever infarction (P<0.05).CONCLUSION:Results indicate that EPVS is related to the incidence of lacunar infarction.Earlier screening of EPVS.and the evaluation of EPVS severity,is of great importance to control the risk factors for cerebral vascular disease and to prevent lacunar infarction.

  17. Accumulation of MRI markers of cerebral small vessel disease is associated with decreased cognitive function. A study in first-ever lacunar stroke and hypertensive patients.

    Directory of Open Access Journals (Sweden)

    Marjolein eHuijts

    2013-11-01

    Full Text Available Background – White matter lesions (WMLs, asymptomatic lacunar infarcts, brain microbleeds (BMBs and enlarged perivascular spaces (EPVS have been identified as silent lesions due to cerebral small vessel disease (cSVD. All these markers have been individually linked to cognitive functioning, but are also strongly correlated with each other. The combined effect of these markers on cognitive function has never been studied and would possibly provide more useful information on the effect on cognitive function. Methods – Brain MRI and extensive neuropsychological assessment were performed in 189 patients at risk for cSVD (112 hypertensive patients and 77 first-ever lacunar stroke patients. We rated the presence of any asymptomatic lacunar infarct, extensive WMLs, any deep BMB, and moderate to extensive EPVS in the basal ganglia. The presence of each marker was summed to an ordinal score between 0 and 4. Associations with domains of cognitive function (memory, executive function, information processing speed and overall cognition were analyzed with correlation analyses. Results – Correlation analyses revealed significant associations between accumulating cSVD burden and decreased performance on all cognitive domains (all p≤.001. Results remained significant for information processing speed (r=-.181, p=.013 and overall cognition (r=-.178, p=.017, after correction for age and sex. Testing of trend using linear regression analyses revealed the same results. Discussion – We tested a new approach to capture total brain damage resulting from cSVD and found that accumulation of MRI burden of cSVD is associated with decreased performance on tests of information processing speed and overall cognition, implying that accumulating brain damage is accompanied by worse cognitive functioning.

  18. Lacunar infarcts: no black holes in the brain are benign.

    Science.gov (United States)

    Norrving, Bo

    2008-08-01

    Lacunar infarcts--small subcortical infarcts that result from occlusion of a single penetrating artery--account for about one quarter of all ischaemic strokes. However, there are many diagnostic pitfalls, and causes other than penetrating small vessel disease in up to one third of cases. Recent studies have shown that the prognosis after lacunar infarcts is not benign; the risk of recurrent stroke is no lower than for other ischaemic stroke subtypes, and there is an increased risk for cognitive decline, dementia and death in the long term. Furthermore, silent small vessel disease in the brain at the time of an index stroke has significant prognostic implications. In the acute phase, response to intravenous thrombolysis appears to be similar to other subtypes of ischaemic strokes. Antiplatelet drugs, careful blood pressure control, statins and modification of lifestyle risk factors are key elements in secondary prevention after lacunar infarcts. PMID:18644908

  19. Lacunar strokes: a single institutional experience

    Directory of Open Access Journals (Sweden)

    Osama Shukir Muhammed Amin

    2013-08-01

    Full Text Available Abstract: Objective: Lacunar ischemic strokes comprise approximately 25% of all ischemic strokes. We compared the risk factors and clinical pattern of this type of stroke between males and females. Methods: This observational study involved 50 consecutive patients with their first-ever lacunar stroke and was conducted at the department of neurology of Sulaimaniya general teaching hospital, Iraq from December 1, 2010 to March 1, 2013. Patients’ risk factors, clinical presentation, and strokes’ patterns were noted and a comparison was made between males and females. Results: Males (64% outnumbered females (36% with a male to female ration of 1.7. The mean age of males was 63 years while it was 61 years in females. Although hypertension was more common in females than in males, diabetes and smoking were more common in the latter group; however, there were no statistically significant differences between the 2 genders in terms of hypertension (P-value <0.3 and diabetes (P-value < 0.07 while smoking was strongly associated with male gender (P-value<0.0001. Pure motor hemiparesis, ataxic hemiparesis, pure sensory stroke, and dysarthria-clumsy hand syndrome were more common in males; only senori-motor stroke revealed a statistically significant difference in favor males (P-value<0.0001; 95% CI -1.7 to 19.2. There was no statistically significant difference in terms of which side of the brain was infarcted between males and females (P-value<0.4. Conclusion: Males around the age of 63 years were the main target for these lacunar strokes. Cigarette smoking and sensorimotor strokes were significantly associated with male gender. [Cukurova Med J 2013; 38(4.000: 659-666

  20. Risk Factors for Silent Lacunar Infarction in Patients with Transient Ischemic Attack.

    Science.gov (United States)

    Li, Ying; Liu, Nan; Huang, Yonghua; Wei, Wei; Chen, Fei; Zhang, Weiwei

    2016-01-01

    BACKGROUND Lacunar infarctions represent 25% of ischemic strokes. Lacunar stroke and transient ischemic attack (TIA) share a number of symptoms. This study aimed to assess the potential risk factors for lacunar infarction in patients with TIA. MATERIAL AND METHODS This was a retrospective study performed at the Beijing Military General Hospital in patients with TIA admitted between March 2010 and December 2011. Patients were grouped according to lacunar vs. no lacunar infarction. All patients were diagnosed using diffusion-weighted imaging (DWI) on brain magnetic resonance imaging (MRI). Brain angiography (computed tomography and MRI) was used to measure intracranial stenosis. Carotid artery stenosis was measured by ultrasound. RESULTS Patients with TIA and lacunar infarction (n=298) were older than those without lacunar infarction (n=157) (69.4±10.0 vs. 58.9±9.0 years, Pdiabetes (32.6% vs. 21.0%, P=0.010), hyperlipidemia (53.4% vs. 29.3%, P<0.001), carotid stenosis (73.2% vs. 40.1%, P<0.001), and intracranial stenosis (55.6% vs. 31.9%, P<0.001), but a lower frequency of alcohol drinking (8.1% vs. 14.0%, P=0.045). Lacunar infarction mostly involved the anterior circulation (62.8%). Multivariate analysis showed that age (odds ratio (OR)=1.085, 95% confidence interval (95%CI): 1.054-1.117, P<0.001), hypertension (OR=1.738, 95%CI: 1.041-2.903, P=0.035), hyperlipidemia (OR=2.169, 95%CI: 1.307-3.601, P=0.003), and carotid stenosis (OR=1.878, 95%CI: 1.099-3.206, P=0.021) were independently associated with lacunar infarction. CONCLUSIONS Age, hypertension, hyperlipidemia, and carotid stenosis were independently associated with silent lacunar infarction in patients with TIA. PMID:26864634

  1. The correlation between cognitive function and cerebral white matter lesions/insulin resistance in patients with lacunar infarction:a clinical study of 184 cases

    Institute of Scientific and Technical Information of China (English)

    张琼予

    2013-01-01

    Objective To investigate the correlation between cognitive function and cerebral white matter lesions(WML)/insulin resistance(IR) in patients with stroke.Methods Between May 2011 and October 2011,the clin-ical data of 184 in-patients with lacunar infarction were

  2. Lacunar infarction:a hemodynamic analysis of 102 cases

    Institute of Scientific and Technical Information of China (English)

    张春玲

    2006-01-01

    Objective To study cerebrovascular lesion and lacunar infarction (LI) and to explore the pathogenesis of LI based on neuroradiological imaging. Methods Brain MRI,CT angiography (CTA) and CT perfusion (CTP) were performed in all 102 patients with LI. Results MRI showed single LI in 3 cases, multiple LI in 99 cases. CTA showed severe stenosis or occlusion of internal

  3. Alterations of mass density and 3D osteocyte lacunar properties in bisphosphonate-related osteonecrotic human jaw bone, a synchrotron µCT study.

    Directory of Open Access Journals (Sweden)

    Bernhard Hesse

    Full Text Available Osteonecrosis of the jaw, in association with bisphosphonates (BRONJ used for treating osteoporosis or cancer, is a severe and most often irreversible side effect whose underlying pathophysiological mechanisms remain largely unknown. Osteocytes are involved in bone remodeling and mineralization where they orchestrate the delicate equilibrium between osteoclast and osteoblast activity and through the active process called osteocytic osteolysis. Here, we hypothesized that (i changes of the mineralized tissue matrix play a substantial role in the pathogenesis of BRONJ, and (ii the osteocyte lacunar morphology is altered in BRONJ. Synchrotron µCT with phase contrast is an appropriate tool for assessing both the 3D morphology of the osteocyte lacunae and the bone matrix mass density. Here, we used this technique to investigate the mass density distribution and 3D osteocyte lacunar properties at the sub-micrometer scale in human bone samples from the jaw, femur and tibia. First, we compared healthy human jaw bone to human tibia and femur in order to assess the specific differences and address potential explanations of why the jaw bone is exclusively targeted by the necrosis as a side effect of BP treatment. Second, we investigated the differences between BRONJ and control jaw bone samples to detect potential differences which could aid an improved understanding of the course of BRONJ. We found that the apparent mass density of jaw bone was significantly smaller compared to that of tibia, consistent with a higher bone turnover in the jaw bone. The variance of the lacunar volume distribution was significantly different depending on the anatomical site. The comparison between BRONJ and control jaw specimens revealed no significant increase in mineralization after BP. We found a significant decrease in osteocyte-lacunar density in the BRONJ group compared to the control jaw. Interestingly, the osteocyte-lacunar volume distribution was not altered after

  4. Changing patterns of residential segregation in a prismatic metropolis: a lacunarity-based study in Houston, 1980 – 2000

    OpenAIRE

    Sui, Daniel Z.; X Ben Wu

    2006-01-01

    The role of race versus class in shaping residential segregation patterns has been a contentious issue in segregation studies for decades. Despite the voluminous, interdisciplinary literature, scholars have reported conflicting evidence on the role of race versus class in residential segregations. We attribute the current inconclusive literature partially to the failure to consider scale explicitly in residential segregation measures, and partially to the growing complexity of a multiethnic m...

  5. Fractal analysis: fractal dimension and lacunarity from MR images for differentiating the grades of glioma.

    Science.gov (United States)

    Smitha, K A; Gupta, A K; Jayasree, R S

    2015-09-01

    Glioma, the heterogeneous tumors originating from glial cells, generally exhibit varied grades and are difficult to differentiate using conventional MR imaging techniques. When this differentiation is crucial in the disease prognosis and treatment, even the advanced MR imaging techniques fail to provide a higher discriminative power for the differentiation of malignant tumor from benign ones. A powerful image processing technique applied to the imaging techniques is expected to provide a better differentiation. The present study focuses on the fractal analysis of fluid attenuation inversion recovery MR images, for the differentiation of glioma. For this, we have considered the most important parameters of fractal analysis, fractal dimension and lacunarity. While fractal analysis assesses the malignancy and complexity of a fractal object, lacunarity gives an indication on the empty space and the degree of inhomogeneity in the fractal objects. Box counting method with the preprocessing steps namely binarization, dilation and outlining was used to obtain the fractal dimension and lacunarity in glioma. Statistical analysis such as one-way analysis of variance and receiver operating characteristic (ROC) curve analysis helped to compare the mean and to find discriminative sensitivity of the results. It was found that the lacunarity of low and high grade gliomas vary significantly. ROC curve analysis between low and high grade glioma for fractal dimension and lacunarity yielded 70.3% sensitivity and 66.7% specificity and 70.3% sensitivity and 88.9% specificity, respectively. The study observes that fractal dimension and lacunarity increases with an increase in the grade of glioma and lacunarity is helpful in identifying most malignant grades.

  6. Tunneling in quantum superlattices with variable lacunarity

    Energy Technology Data Exchange (ETDEWEB)

    Villatoro, Francisco R. [Departamento de Lenguajes y Ciencias de la Computacion, Universidad de Malaga, E-29071 Malaga (Spain); Monsoriu, Juan A. [Departamento de Fisica Aplicada, Universidad Politecnica de Valencia, E-46022 Valencia (Spain)], E-mail: jmonsori@fis.upv.es

    2008-05-19

    Fractal superlattices are composite, aperiodic structures comprised of alternating layers of two semiconductors following the rules of a fractal set. The scattering properties of polyadic Cantor fractal superlattices with variable lacunarity are determined. The reflection coefficient as a function of the particle energy and the lacunarity parameter present tunneling curves, which may be classified as vertical, arc, and striation nulls. Approximate analytical formulae for such curves are derived using the transfer matrix method. Comparison with numerical results shows good accuracy. The new results may be useful in the development of band-pass energy filters for electrons, semiconductor solar cells, and solid-state radiation sources up to THz frequencies.

  7. A software program for quantitative analysis of alveolar oxygen partial pressure (p{sub A}O{sub 2}) with oxygen-sensitive {sup 3}He-MRI; Ein Auswerteprogramm zur quantitativen Analyse von Messungen des alveolaeren Sauerstoffpartialdrucks (p{sub A}O{sub 2}) mit der sauerstoffsensitiven {sup 3}He-MR-Tomographie

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, F.; Gast, K.K.; Schreiber, W.G. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Radiologie; Eberle, B.; Markstaller, K. [Universitaet Mainz (Germany). Klinik fuer Anaesthesiologie; Schmiedeskamp, J. [Mainz Univ. (Germany). Inst. fuer Physik; Bluemler, P. [Max-Planck-Institut fuer Polymerforschung, Mainz (Germany); Kauczor, H.-U. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Radiologie; Deutsches Krebsforschungszentrum, Heidelberg (Germany)

    2004-10-01

    Purpose: To develop a software tool for quantitative analysis of alveolar oxygen partial pressure (p{sub A}O{sub 2}) as well as its time course during apnea. Material and Methods: T{sub 1}-relaxation times of hyperpolarized {sup 3}He are reduced by paramagnetic oxygen rendering {sup 3}He-MRI sensitive to oxygen and thus allowing the assessment of the local oxygen partial pressure in the pulmonary airspaces. Oxygen-related relaxation and loss of polarization by RF-excitation can be discriminated by acquiring two image series with varying interscan delay and/or flip angles. Software was developed to calculate the p{sub A}O{sub 2} and the decay rate in user-defined regions of interest (ROIs) automatically. Moreover, parameter maps can be calculated. In addition to the analysis of 2-dimensional data sets, the software allows the evaluation of 3-dimensional measurements for the first time. Artifacts due to lung motion were reduced by implementing a motion correction algorithm. Results: The software was successfully applied to data sets from healthy volunteers and from patients with various lung diseases. The parameter maps demonstrated a more homogeneous distribution of p{sub A}O{sub 2} for the volunteers than for the patients. A regional increase in p{sub A}O{sub 2} was found in a few patients. Conclusion: the described software allows the absolute quantification of p{sub A}O{sub 2} as well as its variation over time. In the future therefore, the software may gain importance for detecting mis-matches between ventilation and perfusion, e.g., in patients with pulmonary embolism or chronic obstructive lung diseases. (orig.)

  8. An interactive mapping tool for visualizing lacunarity of laser scanned point clouds

    Science.gov (United States)

    Kania, Adam; Székely, Balázs

    2016-04-01

    Lacunarity, a measure of the spatial distribution of the empty space in a certain model or real space over large spatial scales, is found to be a useful descriptive quantity in many fields using imagery, including, among others, geology, dentistry, neurology. Its application in ecology was suggested more than 20 years ago. The main problem of its application was the lack of appropriate high resolution data. Nowadays, full-waveform laser scanning, also known as FWF LiDAR, provides the tool for mapping the vegetation in unprecedented details and accuracy. Consequently, the lacunarity concept can be revitalized, in order to study the structure of the vegetation in this sense as well. Calculation of lacunarity, even if it is done in two dimensions (2D), is still has its problems: on one hand it is a number-crunching procedure, on the other hand, it produces 4D results: at each 3D point it returns a set of data that are function of scale. These data sets are difficult to visualize, to evaluate, and to compare. In order to solve this problem, an interactive mapping tool has been conceptualized that is designed to manipulate and visualize the data, lets the user set parameters for best visualization or comparison results. The system is able to load large amounts of data, visualize them as lacunarity curves, or map view as horizontal slices or in 3D point clouds coloured according to the user's choice. Lacunarity maps are presented as a series of (usually) horizontal profiles, e.g. rasters, which cells contain color-mapped values of selected lacunarity of the point cloud. As lacunarity is usually analysed in a series of successive windows sizes, the tool can show a series of rasters with sequentially animated lacunarity maps calculated for various window sizes. A very fast switching of colour schemes is possible to facilitate rapid visual feedback to better understand underlying data patterns exposed by lacunarity functions. In the comparison mode, two sites (or two areas

  9. Fractal Dimension and Lacunarity analysis of mammographic patterns in assessing breast cancer risk related to HRT treated population

    DEFF Research Database (Denmark)

    Karemore, Gopal Raghunath; Nielsen, Mads

    2009-01-01

    the complexity while the Lacunarity characterize the gappiness of a fractal. Our cross-sectional case-control study includes mammograms of 50 patients diagnosed with breast cancer in the subsequent 2-4 years and 50 matched controls. The longitudinal double blind placebo controlled HRT study includes 39 placebo......  Structural texture measures are used to address the aspect of breast cancer risk assessment in screening mammograms. The current study investigates whether texture properties characterized by local Fractal Dimension (FD) and Lacunarity contribute to asses breast cancer risk. FD represents....... It was found that there were no differences between cancer and control group for FD (P=0.8) and Lacunarity (P=0.8) in cross-sectional study whereas earlier published heterogeneity examination of radiographs (BC-HER) breast cancer risk score separated groups (p=0.002). In the longitudinal study, FD decreased...

  10. Occlusive lesions of carotid and intracranial arteries in patients with symptomatic lacunar infarction. Evaluation by MR angiography

    International Nuclear Information System (INIS)

    The purpose of this study is to elucidate the prevalence and degree of occlusive lesions of carotid and intracranial arteries in patients with symptomatic lacunar infarction. We performed carotid and intracranial MR angiography, and T2-weighted MRI on 65 patients with symptomatic lacunar infarction. Stenosis of more than 25% narrowing of the diameter was found in 12 patients (18.5%) in the extracranial carotid arteries and in 14 patients (21.5%) in the intracranial arteries. Most of the stenotic lesions were mild. Multiple logistic regression analysis showed that age was significant and independent predictor for carotid artery stenosis, and that diabetes mellitus was predictor for intracranial artery stenosis. The incidence of intracranial artery stenosis was statistically higher in patients with a symptomatic lacunar infarctions in subcortical white matter area on T2-weighted MRI than in patients without such lesions. Coexistence of carotid artery stenosis should be suspected in aged patients with symptomatic lacunar infarction, and the possibility of intracranial artery stenosis should be considered in patients with diabetes mellitus or asymptomatic lacunar infarctions in subcortical white matter area. (author)

  11. Correlative factors of cognitive impairment in patients with lacunar infarcts

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Patients with lacunar infarcts are thought tohave an increased risk of cognitive i mpair ment anddementia[1].Cognitive i mpair ment is a predictor ofpoor functional outcome in stroke survivors[2].However,in patients with lacunar infarcts,thepathway leading to cognitive i mpair ment is notclear.According to the lacunar hypothesis,cogni-tive i mpair ment results fromincreased number andvolume of lacunes,especially whenlocated strategi-cally within frontal subcortical loops[3];while Feinet al[4]found that cogn...

  12. A lacunarity-based approach to evaluate Martian surfaces

    Science.gov (United States)

    Székely, Balázs; Kania, Adam; Magyar, Zoltán

    2016-04-01

    Terrestrial planets show great variety in terms of geomorphological patterns: the surface is shaped on one hand by the various phases of asteroid bombardment, on the other hand internal and external processes create or have created landform elements at various scales. This richness in forms have already been considered in terms of fractal or multifractal analyses, resulting in various considerations. However, so far the counterpart of the fractal analysis, the lacunarity analysis has been seldom carried out. Lacunarity, a measure of the spatial distribution of the empty space in a certain model or real space over large spatial scales, is found to be a useful descriptive quantity in many fields using imagery. Lacunarity can be calculated in various dimensions; in most of the cases 2D calculation is performed. Our project also aims at calculating 2D lacunarity curves, however, we also use digital terrain models (DTMs) of the planet Mars, introducing partly the third dimension into the calculation. DTMs are converted to horizontal slices of the topography and these slices are then treated as images. The lacunarity analysis is performed on these stacks of images resulting in large amount of lacunarity curves. These curves can be compared locally or regionally, and the set of curves can be used for more global comparisons. Our preliminary results show that characteristic differences can be detected between various Martian surface types, i.e. the lacunarity results, similar to fractal dimensions, have a certain descriptive power. As this type of lacunarity analysis provide larger amount of descriptors (multiple lacunarity functions) than the fractal dimension values and the scale of analysis (area of interest taken into account in the computing) can be selected according to the needs, it seems to be possible to create lacunarity libraries for general use. In this preliminary phase of the project tools and techniques are tested to compare effectively the resulting

  13. Prospective study of disturbance of intelligence of patients with lacunar stroke%腔隙性脑梗死患者智能障碍的前瞻性研究

    Institute of Scientific and Technical Information of China (English)

    陈湛愔; 陈逢俭; 梁秀竹

    2003-01-01

    Aim To find the regularity of disturbance of intelligence through prospective study of patients with lacunar stroke.Methods 186 patients with lacunar stroke recruited in Department of Neurology of Affiliated Central Hospital of Guangdong Medical College entered this study,51 cases were combined with slight aphemia and most of them achieved obvious improvement within one week after hopitalization,and aphasis was not seen in others.The symptoms of limb paralysis of all the patients were slight and the muscular strengths were all above grade IV,which were improved obviously within one week.Then all the 186 cases were measured with adult intelligence table and multiple correlation analysis was done according to sex,age,job and education extent of patients and image characteristics.Results The intelligence of 130 patients with lacunar stroke was lower than normal and accounted for 70% of 186 cases.51 cases belonged to severe disturbance of intelligence(VIQ< 69) and accounted for 27.4% .The relationship between education extent and disturbance of intelligence presented significant negative correlation(r=-0.6307,P=0.001).The cerebral infarction in left - side basal ganglion,area of corona radiata and left - side temporal lobe could easily cause disturbance of intelligence(r=-0.217,P=0.003) than right side.Binswanger syndrome was the important reason leading to disturbance of intelligence(r=-0.2677,P< 0.001).Conclusion Different lesion locus often leads to obviously different extent of disturbance of intelligence.Left hemisphere lesion could easily cause disturbance of intelligence,especially left basal ganglion and temporal lobe.The disturbance of intelligence of patients with multiple locus is severer than that with single locus.In addition,single infracortical cava stroke can cause obvious disturbance of intelligence.The disturbance of intelligence caused by sex,age and job has no correlation with that caused by infracortical cava stroke,but it presents negative

  14. Fractal and Lacunarity Analyses: Quantitative Characterization of Hierarchical Surface Topographies.

    Science.gov (United States)

    Ling, Edwin J Y; Servio, Phillip; Kietzig, Anne-Marie

    2016-02-01

    Biomimetic hierarchical surface structures that exhibit features having multiple length scales have been used in many technological and engineering applications. Their surface topographies are most commonly analyzed using scanning electron microscopy (SEM), which only allows for qualitative visual assessments. Here we introduce fractal and lacunarity analyses as a method of characterizing the SEM images of hierarchical surface structures in a quantitative manner. Taking femtosecond laser-irradiated metals as an example, our results illustrate that, while the fractal dimension is a poor descriptor of surface complexity, lacunarity analysis can successfully quantify the spatial texture of an SEM image; this, in turn, provides a convenient means of reporting changes in surface topography with respect to changes in processing parameters. Furthermore, lacunarity plots are shown to be sensitive to the different length scales present within a hierarchical structure due to the reversal of lacunarity trends at specific magnifications where new features become resolvable. Finally, we have established a consistent method of detecting pattern sizes in an image from the oscillation of lacunarity plots. Therefore, we promote the adoption of lacunarity analysis as a powerful tool for quantitative characterization of, but not limited to, multi-scale hierarchical surface topographies. PMID:26758776

  15. MRI findings in patients with multiple lacunar infarcts manifesting hyperactive-type delirium

    Energy Technology Data Exchange (ETDEWEB)

    Arahata, Yutaka; Motegi, Yoshimasa; Furuse, Masahiro (Nakatsugawa Municipal General Hospital, Gifu (Japan)); Watanabe, Masaki; Takahashi, Akira

    1994-04-01

    MRI studies were carried out on 69 patients with multiple lacunar infarcts: 32 had hyperactive-type delirium and the other 37 were non-delirious controls. Between the two groups, there were no statistically significant differences in mean age and sex distribution. In the corona radiata and basal ganglia, the number of infarcts did not differ between the two groups. However, the extent of thalamic infarcts and periventricular hyperintensity (PVH), the maximal width of the third ventricle and Evans' ratio among the delirious patients were significantly larger than those in the controls. In conclusion, thalamic lesions and diffuse advanced PVH may have an intimate correlation in the development of hyperactive-type delirium in patients with multiple lacunar infarcts. (author).

  16. Biomaterial porosity determined by fractal dimensions, succolarity and lacunarity on microcomputed tomographic images

    Energy Technology Data Exchange (ETDEWEB)

    N' Diaye, Mambaye [LUNAM Université, GEROM Groupe Etudes Remodelage Osseux et bioMatériaux-LHEA, IRIS-IBS Institut de Biologie en Santé, CHU d' Angers, 49933 ANGERS Cedex (France); Degeratu, Cristinel [LUNAM Université, GEROM Groupe Etudes Remodelage Osseux et bioMatériaux-LHEA, IRIS-IBS Institut de Biologie en Santé, CHU d' Angers, 49933 ANGERS Cedex (France); University Politehnica of Bucharest, Faculty of Applied Chemistry and Materials Science, Department of Bioresources and Polymer Science, Calea Victoriei 149, 010072, Sector 1, Bucharest (Romania); Bouler, Jean-Michel [Inserm UMR 791, LIOAD, University of Nantes, 44000 Nantes (France); Chappard, Daniel, E-mail: daniel.chappard@univ-angers.fr [LUNAM Université, GEROM Groupe Etudes Remodelage Osseux et bioMatériaux-LHEA, IRIS-IBS Institut de Biologie en Santé, CHU d' Angers, 49933 ANGERS Cedex (France)

    2013-05-01

    Porous structures are becoming more and more important in biology and material science because they help in reducing the density of the grafted material. For biomaterials, porosity also increases the accessibility of cells and vessels inside the grafted area. However, descriptors of porosity are scanty. We have used a series of biomaterials with different types of porosity (created by various porogens: fibers, beads …). Blocks were studied by microcomputed tomography for the measurement of 3D porosity. 2D sections were re-sliced to analyze the microarchitecture of the pores and were transferred to image analysis programs: star volumes, interconnectivity index, Minkowski–Bouligand and Kolmogorov fractal dimensions were determined. Lacunarity and succolarity, two recently described fractal dimensions, were also computed. These parameters provided a precise description of porosity and pores' characteristics. Non-linear relationships were found between several descriptors e.g. succolarity and star volume of the material. A linear correlation was found between lacunarity and succolarity. These techniques appear suitable in the study of biomaterials usable as bone substitutes. Highlights: ► Interconnected porosity is important in the development of bone substitutes. ► Porosity was evaluated by 2D and 3D morphometry on microCT images. ► Euclidean and fractal descriptors measure interconnectivity on 2D microCT images. ► Lacunarity and succolarity were evaluated on a series of porous biomaterials.

  17. Location of lacunar infarcts correlates with cognition in a sample of non-disabled subjects with age-related white-matter changes: the LADIS study

    DEFF Research Database (Denmark)

    Benisty, S; Gouw, A A; Porcher, R;

    2009-01-01

    OBJECTIVES: In cerebral small vessel disease, white-matter hyperintensities (WMH) and lacunes are both related to cognition. Still, their respective contribution in older people remains unclear. The purpose of this study is to assess the topographic distribution of lacunes and determine whether i...

  18. 维生素B12与腔隙性梗死后抑郁的相关性分析%Study on the association of Vitamin B12 and depression secondary to lacunar cerebral infarction

    Institute of Scientific and Technical Information of China (English)

    唐劭年; 任兰振; 胡宗继; 刘立雄

    2014-01-01

    目的:对维生素B12与腔隙性梗死后抑郁存在的相关性进行探讨。方法将我院2011-01-2013-01收治的腔隙性梗死患者798例分为对照组708例与观察组90例,对照组无抑郁症,观察组存在抑郁症(根据汉密尔顿抑郁量表判定),对比并分析2组患者的维生素B12水平。结果对照组血清维生素B12平均浓度为(178.6±20.7)pmol/L ,维生素B12缺乏197例(27.9%),观察组,血清维生素 B12平均浓度(141.7±19.7)pmol/L ,维生素 B12缺乏60例(66.7%),2组比较差异均有统计学意义( P<0.05)。结论维生素B12缺乏与腔隙性梗死后抑郁存在着相关性,腔隙性梗死并抑郁患者的维生素B12水平较普通腔隙性梗死患者更低,维生素B12缺乏情况较为明显,在治疗过程中适当补充维生素B12可以让患者的抑郁症状得到缓解,并可提升腔隙性梗死的治疗效果,促进患者恢复。%Objective To investigate the relevance between vitamin B12 and depression after lacunar cerebral infarc-tion.Methods Seventy hundred and ninety-eight patients with lacunar cerebral infarction admitted to our hospital from January 2011 to January 2011 were divided into control group(708 cases) and observation group (90 cases) ,no depression in control group patients ,the observation group patients had depression (judged according to the Hamilton depression rating scale ) ,vita-min B12 levels of patients in the two groups were analyzed and compared.Results The mean concentration of serum vitamin B12 of the control group was(178.6 ± 20.7)pmol/L ,the number of patients with vitamin B12 deficiency was 197 ,the ratio of which was 27.9% ;In the observation group ,the mean concentration of serum vitamin B12 was(141.7 ± 19.7)pmol/L ,the number of patients with vitamin B12 deficiency was 60 ,the ratio of which was 66.7%.The difference between the two groups had statisti-cal significance (P<0.05). Conclusion There is

  19. Preliminary analysis of osteocyte lacunar density in long bones of tetrapods: all measures are bigger in sauropod dinosaurs.

    Directory of Open Access Journals (Sweden)

    Koen W H Stein

    Full Text Available Osteocytes harbour much potential for paleobiological studies. Synchrotron radiation and spectroscopic analyses are providing fascinating data on osteocyte density, size and orientation in fossil taxa. However, such studies may be costly and time consuming. Here we describe an uncomplicated and inexpensive method to measure osteocyte lacunar densities in bone thin sections. We report on cell lacunar densities in the long bones of various extant and extinct tetrapods, with a focus on sauropodomorph dinosaurs, and how lacunar densities can help us understand bone formation rates in the iconic sauropod dinosaurs. Ordinary least square and phylogenetic generalized least square regressions suggest that sauropodomorphs have lacunar densities higher than scaled up or comparably sized mammals. We also found normal mammalian-like osteocyte densities for the extinct bovid Myotragus, questioning its crocodilian-like physiology. When accounting for body mass effects and phylogeny, growth rates are a main factor determining the density of the lacunocanalicular network. However, functional aspects most likely play an important role as well. Observed differences in cell strategies between mammals and dinosaurs likely illustrate the convergent nature of fast growing bone tissues in these groups.

  20. Hemodynamic factors may play a critical role in neurological deterioration occurring within 72 hrs after lacunar stroke.

    Directory of Open Access Journals (Sweden)

    Yen-Chu Huang

    Full Text Available BACKGROUND: Whether a perfusion defect exists in lacunar infarct and whether it is related to early neurological deterioration (END is still under debate. The aim of this study was to evaluate whether END in lacunar infarct is related to a perfusion defect using diffusion-weighted imaging (DWI, diffusion tensor imaging (DTI and perfusion MR imaging. METHODS: One hundred and forty-one consecutive patients had an MRI scan within 30 hours after onset of symptoms and 43 patients with acute lacunar infarct and classic lacunar syndrome were recruited. The MRI sequences included DWI, DTI and cerebral blood flow (CBF maps to respectively represent the topographic locations of acute infarcts, the corticospinal tract and perfusion defects. The END was defined in reference to the National Institute of Health Stroke Scale (NIHSS as an increase ≧2 within 72 hours. Cohen's Kappa coefficient was used to examine the reliability between the 2 image readers. A multivariate logistic regression model was constructed adjusting for baseline variables. RESULTS: Ten out of the 43 patients had END. Patients having END was significantly associated with lower chances of favorable and good outcomes at 3 months (p = 0.01 and p = 0.002, respectively. END was predicted when the non-core hypoperfused area overlapped on the corticospinal tract, which is defined as the expected END profile. Cohen's Kappa coefficient between the 2 image readers to define images of expected END profiles was 0.74. In 15 patients with expected END profile, 9 had END clinically, whereas 28 patients had no expected END profile, and only 1 patient had END (p<0.0001. After adjusting for sex, the expected END profile was still associated with END (odds ratio, 42.2; p = 0.002. CONCLUSION: Our study demonstrated that the END in acute lacunar stroke is likely related to the transformation of non-core hypoperfused area into infarction in the anatomy of corticospinal tracts.

  1. Poromicromechanics reveals that physiological bone strains induce osteocyte-stimulating lacunar pressure.

    Science.gov (United States)

    Scheiner, Stefan; Pivonka, Peter; Hellmich, Christian

    2016-02-01

    Mechanical loads which are macroscopically acting onto bony organs, are known to influence the activities of biological cells located in the pore spaces of bone, in particular so the signaling and production processes mediated by osteocytes. The exact mechanisms by which osteocytes are actually able to "feel" the mechanical loading and changes thereof, has been the subject of numerous studies, and, while several hypotheses have been brought forth over time, this topic has remained a matter of debate. Relaxation times reported in a recent experimental study of Gardinier et al. (Bone 46(4):1075-1081, 2010) strongly suggest that the lacunar pores are likely to experience, during typical physiological load cycles, not only fluid transport, but also undrained conditions. The latter entail the buildup of lacunar pore pressures, which we here quantify by means of a thorough multiscale modeling approach. In particular, the proposed model is based on classical poroelasticity theory, and able to account for multiple pore spaces. First, the model reveals distinct nonlinear dependencies of the resulting lacunar (and vascular) pore pressures on the underlying bone composition, highlighting the importance of a rigorous multiscale approach for appropriate computation of the aforementioned pore pressures. Then, the derived equations are evaluated for macroscopic (uniaxial as well as hydrostatic) mechanical loading of physiological magnitude. The resulting model-predicted pore pressures agree very well with the pressures that have been revealed, by means of in vitro studies, to be of adequate magnitude for modulating the responses of biological cells, including osteocytes. This underlines that osteocytes may respond to many types of loading stimuli at the same time, in particular so to fluid flow and hydrostatic pressure. PMID:26220453

  2. 腔隙性脑梗死患者脑微出血与血清同型半胱氨酸的相关性研究%The Study of Cerebral Microbleeds and Homocysteine in Lacunar Infarction

    Institute of Scientific and Technical Information of China (English)

    张金; 郝冬琳; 何国平

    2014-01-01

    目的:分析腔隙性脑梗死患者脑微出血(CMB)与血清同型半胱氨酸(Hcy)的关系。方法选择急性腔隙性脑梗死患者85例,行MR SWI序列检查,根据CMB的数量,分为轻度(1个CMB)、中度(4个CMB)、重度CMB(10个以上CMB)组。记录患者临床特点,检测患者血清Hcy水平,分析Hcy与CMB的关系。结果85例急性腔隙性脑梗死患者中,有CMB 35例(41.2%),其中轻度CMB组5例、中度CMB组10例、重度CMB组20例。血清同型半胱氨酸:CMB轻度组(14.2±3.1)μmol·L-1,中度组(17.5±2.6)μmol·L-1,重度组(19.0±3.8)μmol·L-1,方差分析发现,组间比较差异有统计学意义(F=4.579,P=0.019);CMB重度组血清Hcy水平高于轻度及中度组(P<0.05);Spearm相关分析发现CMB病变程度与血清Hcy水平呈正相关(r=0.768,P<0.001)。结论血清Hcy与腔隙性脑梗死患者的CMB有关,Hcy是CMB可能的危险因素;Hcy可以作为脑小血管病损伤的标志物之一,对CMB诊断和治疗有重要意义。%Aim To investigate the associations between the presence of cerebral microbleeds (CMB) and homocysteine (Hcy) in lacunar infarction. Methods Eighty five lacunar infarction patients were enrolled. All patients received cranial magnetic resonance imaging included susceptibility-weighted imaging at the ifrst week. The serum levels of Hcy were detected in patients. Results Among a total of 85 patients, 35(41.2%) patients were detected with CMB. The Hcy levels were (14.2±3.1) μmol·L-1 in mild CMB group, (17.5±2.6)μmol·L-1 in moderate CMB group, (19.0±3.8)μmol·L-1 in severe CMB group, and there were signiifcant differences by analysis of variance (F=4.579,P=0.019). The Hcy levels in severe CMB group were higher than that of mild and moderate CMB group (P<0.05). Spearm analysis indicated that the severity of CMB was positively related with Hcy levels (r=0.768, P<0.001). Conclusion CMB have a relatively high prevalence in lacunar infarction. Hcy is

  3. Lacunarity of geophysical well logs in the Cantarell oil field, Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Arizabalo, Ruben Dario [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico); Oleschko, Klavdia [Centro de Geociencias, Universidad Nacional Autonoma de Mexico, Juriquilla, Queretaro (Mexico); Korvin, Gabor [King Fahd University, Dhahran (Saudi Arabia); Lozada, Manuel [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico); Castrejon, Ricardo [Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico); Ronquillo, Gerardo [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico)

    2006-04-15

    Lacunarity and fractal variations in geophysical well logs are associated with stratigraphic and petrophysical properties of the naturally fractured Cantarell field in the Gulf of Mexico. Neutron porosity (NPHI), density (RHOB, DRHO, PEF), resistivity (LLD, LLS, MSFL), natural radioactivity (GR, CGR, URAN, POTA, THOR) and caliper (CALI) logs are studied. The resistivity logs yielded remarkably high lacunarity values, especially in the hydrocarbon source- and reservoir rocks. Lacunarity {delta} was found to depend on the resolution and radial depth of penetration of the logging method. It systematically increased in the following order: {delta}(RHOB) < {delta}(CALI) < {delta}(PEF) < {delta}(URAN) < {delta}(GR) < {delta}(NPHI) < {delta}(POTA) < {delta}(CGR) < {delta}(THOR) < {delta}(MSFL) < {delta}(DRHO) < {delta}(LLS) < {delta}(LLD). [Spanish] En este trabajo fueron analizadas las variaciones fractales y de lagunaridad de los registros geofisicos de pozo, con el fin de asociarlos con las propiedades estratigraficas y petrofisicas del yacimiento naturalmente fracturado de Cantarell, en el Golfo de Mexico. Los registros considerados fueron: porosidad neutron (NPHI), densidad (RHOB, DRHO, PEF), resistividad (LLD, LLS, MSFL), radiactividad natural (GR, CGR, URAN, POTA, THOR) y caliper (CALI). Los registros de resistividad produjeron valores de lagunaridad notablemente altos, especialmente en las rocas generadoras y almacenadoras, a diferencia de los demas registros, cuya homogeneidad de traza implico una baja lagunaridad. Los resultados indican que la lagunaridad observada depende de la resolucion y profundidad radial de penetracion del metodo geofisico estudiado y aumenta sistematicamente en el siguiente orden: {delta}(RHOB) < {delta}(CALI) < {delta}(PEF) < {delta}(URAN) < {delta}(GR) < {delta}(NPHI) < {delta}(POTA) < {delta}(CGR) < {delta}(THOR) < {delta}(MSFL) < {delta}(DRHO) < {delta}(LLS) < {delta}(LLD).

  4. The cast imaging of the osteon lacunar-canalicular system and the implications with functional models of intracanalicular flow.

    Science.gov (United States)

    Pazzaglia, Ugo E; Congiu, Terenzio

    2013-02-01

    A casting technique with methyl-methacrylate (MMA) was applied to the study of the osteon lacunar-canalicular network of human and rabbit cortical bone. The MMA monomer infiltration inside the vascular canals and from these into the lacunar-canalicular system was driven by capillarity, helped by evaporation and the resulting negative pressure in a system of small pipes. There was uniform, centrifugal penetration of the resin inside some osteons, but this was limited to a depth of four to five layers of lacunae. Moreover, not all of the osteon population was infiltrated. This failure can be the result of one of two factors: the incomplete removal of organic debris from the canal and canalicular systems, and lack of drainage at the osteon external border. These data suggest that each secondary osteon is a closed system with a peripheral barrier (represented by the reversal line). As the resin advances into the osteon, the air contained inside the canalicula is compressed and its pressure increases until infiltration is stopped. The casts gave a reliable visualization of the lacunar shape, position and connections between the lacunae without the need for manipulations such as cutting or sawing. Two systems of canalicula could be distinguished, the equatorial, which connected the lacunae (therefore the osteocytes) lying on the same concentric level, and the radial, which established connections between different levels. The equatorial canalicula radiated from the lacunar border forming ramifications on a planar surface around the lacuna, whereas the radial canalicula had a predominantly straight direction perpendicular to the equatorial plane. The mean length of the radial canalicula was 40.12 ± 10.26 μm in rabbits and 38.4 ± 7.35 μm in human osteons; their mean diameter was 174.4 ± 71.12 nm and 195.7 ± 79.58 nm, respectively. The mean equatorial canalicula diameter was 237 ± 66.04 nm in rabbit and 249.7 ± 73.78 nm in human bones, both significantly larger (P

  5. Late Onset Bipolar Disorder due to a Lacunar State

    OpenAIRE

    Elena Antelmi; Margherita Fabbri; Lucia Cretella; Maria Guarino; Andrea Stracciari

    2014-01-01

    Objective. To describe a patient with a new onset bipolar disorder (BD) type II, secondary to a lacunar state. Background. Poststroke BD is rare and mainly associated with lesion in the prefrontal-striatal-thalamic circuit. Materials and Methods. A 51-year-old woman came to our attention for a mood disorder of recent onset. At 49, she had suffered acute left-sided limb weakness that improved spontaneously four days later. Arterial hypertension was subsequently diagnosed. After 6 months, she b...

  6. Cheyne-Stokes Respiration in Patients with First-Ever Lacunar Stroke

    Directory of Open Access Journals (Sweden)

    Marc Bonnin-Vilaplana

    2012-01-01

    Full Text Available The aim of this single-center prospective study was to assess the presence of Cheyne-Stokes respiration (CSR and CSR-related variables in 68 consecutive patients with radiologically proven first-ever lacunar stroke undergoing a respiratory sleep study using a portable respiratory polygraph within the first 48 hours of stroke onset. CSR was diagnosed in 14 patients (20.6%. Patients with CSR as compared with those without CSR showed a significantly higher mean (standard deviation, SD apnea-hypopnea index (AHI (34.9 (21.7 versus 18.5 (14.4, P=0.001 and central apnea index (13.1 (13.8 versus 1.8 (3.4, P=0.0001 as well as higher scores of the Barthel index and the Canadian Neurological scale as a measure of stroke severity, and longer hospital stay. CSR was present in one of each five patients with lacunar stroke. The presence of CSR was associated with a trend towards a higher functional stroke severity and worse prognosis.

  7. The Association Between Specific Substances of Abuse and Subcortical Intracerebral Hemorrhage versus Ischemic Lacunar Infarction

    Directory of Open Access Journals (Sweden)

    Emma H Kaplan

    2014-09-01

    Full Text Available Background: Hypertension damages small vessels, resulting in both lacunar infarction and subcortical intracerebral hemorrhage (ICH. Substance abuse has also been linked to small vessel pathology. This study explores whether the use of specific substances (eg., cocaine, tobacco is associated with subcortical ICH over ischemia in hypertensive individuals.Methods: Patients with hypertension, admitted with lacunar infarcts (measuring 1 drink per day (women, >2 drinks per day (men. Logistic regression was performed with ICH as the dependent variable comparing those presenting with ICH to those presenting with ischemia.Results: Of the 580 patients included in analysis, 217 (37% presented with ICH. The average age was similar between the two groups (64.7 versus 66.3 years. Illicit/controlled drug use was associated with a significantly increased risk of ICH over stroke in unadjusted models (25% versus 15%, p=0.02, with the largest effect seen in users ≥65 years old (not statistically significant. Smoking was associated with ischemia over ICH in a dose-dependent manner: any history of smoking OR 1.84, CI 1.19-2.84; current use OR 2.23, CI 1.37-3.62; heavy use OR 2.48, CI 1.50-4.13. Alcohol use was not preferentially associated with either outcome (p=0.29.Conclusions: In hypertensive patients, tobacco use is associated with an increased risk of subcortical ischemia compared to ICH; while use of illicit/controlled substances appears to be predictive of hemorrhage.

  8. Late Onset Bipolar Disorder due to a Lacunar State

    Directory of Open Access Journals (Sweden)

    Elena Antelmi

    2014-01-01

    Full Text Available Objective. To describe a patient with a new onset bipolar disorder (BD type II, secondary to a lacunar state. Background. Poststroke BD is rare and mainly associated with lesion in the prefrontal-striatal-thalamic circuit. Materials and Methods. A 51-year-old woman came to our attention for a mood disorder of recent onset. At 49, she had suffered acute left-sided limb weakness that improved spontaneously four days later. Arterial hypertension was subsequently diagnosed. After 6 months, she began to suffer from alternating brief periods of expansive and elevated mood with longer periods of depressed mood, with a suicide attempt. We performed extensive laboratory and instrumental investigations, as well as, psychiatric consultation, and a cognitive assessment, which was repeated 9 months later. Results. Brain magnetic resonance disclosed leukoaraiosis and a lacunar state of the basal ganglia. Transcranial Doppler showed a patent foramen ovale. A psychiatric consultation led to the diagnosis of BP type II. Neuropsychological evaluation detected deficits in attention/executive functions, verbal fluency, and memory. Nine months later, after specific psychiatric therapy, the psychiatric symptoms were remarkably improved. Conclusion. Our case sheds light on the role of the basal ganglia in mood disorders and the importance of ruling out brain injury in late onset BP.

  9. Lacunar stroke in a teenager after minor head trauma: case report and literature review.

    Science.gov (United States)

    Zwank, Michael D; Dummer, Benjamin W; Danielson, Levi T; Haake, Bret C

    2014-09-01

    Ischemic strokes in children and young adults are fortunately rare. Contrasted with adult ischemic strokes, pediatric stroke etiologies vary greatly and are often unknown. Childhood lacunar strokes and trauma-induced strokes represent particularly uncommon subsets and have been reported infrequently in the literature. It is unique to find a combination of the 2-a lacunar stroke induced by trauma. Underreporting of these trauma-induced ischemic strokes could be responsible for perpetuating the lack of recognition. Here we present a lacunar stroke in a young woman associated with a water sport accident and explore relevant literature encircling deep brain ischemia coinciding with trauma.

  10. Millennium Simulation Dark Matter Haloes: Multi-fractal and Lacunarity Analysis with Homogeneity Transition

    CERN Document Server

    Chacón-Cardona, César A

    2012-01-01

    We investigate from the fractal viewpoint the way in which the dark matter is grouped at z = 0 in the Millennium dark matter cosmological simulation. The determination of the cross to homogeneity in the Millennium Simulation data is described from the behaviour of the fractal dimension and the lacunarity. We use the sliding window technique to calculate the fractal mass-radius dimension, the pre-factor F and the lacunarity of this fractal relation. Besides, we determinate the multi-fractal dimension and the lacunarity spectrum, including their dependence with radial distance. This calculations show a radial distance dependency of all the fractal quantities, with heterogeneity clustering of dark matter haloes up to depths of 100 Mpc/h. The dark matter haloes clustering in the Millennium Simulation shows a radial distance dependency, with two regions clearly defined. The lacunarity spectrum for values of the structure parameter q >= 1 shows regions with relative maxima, revealing the formation of clusters and v...

  11. EVALUATION OF VERTICAL LACUNARITY PROFILES IN FORESTED AREAS USING AIRBORNE LASER SCANNING POINT CLOUDS

    Directory of Open Access Journals (Sweden)

    B. Székely

    2016-06-01

    Logarithms of lacunarity functions show canopy-related variations, we analysed these variations along transects. The spatial variation can be related to forest properties and ecology-specific aspects.

  12. Multimodal magnetic resonance imaging for assessing lacunar infarction after proximal middle cerebral artery occlusion in a canine model

    Institute of Scientific and Technical Information of China (English)

    LU Shan-shan; LIU Sheng; ZU Qing-quan; XU Xiao-quan; WANG Jian-wei; YU Jing; SUN Lei; SHI Hai-bin

    2013-01-01

    Background A new lacunar infarction model was recently established in beagle dogs through proximal middle cerebral artery (MCA) occlusion by thrombus.This study aimed to characterize the model by multimodal magnetic resonance imaging (MRI) and to investigate its potential role for the future stroke research.Methods The left proximal MCA was embolized with an autologous thrombus in six beagles.Diffusion-weighted imaging (DWl) and T2-weighted imaging (T2Wl) were performed every half hour during the first six hours after occlusion,followed by three time points at 12 hours,24 hours,and one week.Perfusion-weighted imaging (PWl) and magnetic resonance angiography (MRA) were carried out at six hours,24 hours and one week.The PWI-DWl mismatch ratio was defined as (PWI-DWI)/DWI ischemic volume.Results Lacunar infarcts induced by MCA occlusion were located in the left caudate nucleus and internal capsule.All the lesions could be detected within two hours by DWI.Lesion volume on DWI increased in a time dependent manner,from (87.19±67.16) mm3 at one hour up to (368.98±217.05) mm3 at 24 hours (P=-0.009),while that on PWI gradually decreased from (7315.00±2054.38) mm3 at six hours to (4900.33±1319.71) mm3 at 24 hours and (3334.33±1195.11) mm3 at one week (P=0.002).The mismatch ratio was 41.93±22.75 at six hours after ischemia,showing "extensive mismatch",and decreased to 18.10+13.74 at 24 hours (P=0.002).No MCA recanalization was observed within 24 hours after MCA occlusion.Conclusions Lacunar infarction induced by proximal MCA occlusion could be detected early by DWI and was characterized by extensive PWI-DWI mismatch.Multimodal MRI is useful to demonstrate the natural evolution of PWI-DWI mismatch.This ischemic model could be further used for investigating early thrombolysis in lacunar stroke showing extensive mismatch.

  13. The relation between prognosis and nocturnal blood pressure variation in hypertensive patients with lacunar infarct%夜间血液变化与高血压腔隙性脑梗死发后及预后的相关性分析

    Institute of Scientific and Technical Information of China (English)

    张微微; 黄勇华; 李娟; 冯军

    2001-01-01

    Objective We conducted a study using MRI and ambulatory blood pressure monitoring(ABPM) to determine whether an inapporpriately low nocturnal blood pressure,or an excess fall in nocturnal blood pressure,might be responsible for lacunar infarct.Method ABPM and Casul blood pressure(CBP) were examined in 35 hypertentives with lacunar infarct( LI) and 33 hypertentives without lacunar infarct as control group.Results There is no significant difference of CBP between two groups.But the mean nighttime systolic blood pressure(nSBP) and diastolic blood pressure(nDBP) in patients with lacunar infarct were significantly smaller than in patients without lacunar infarct.The ratio of nSBP/dSBP and nDBP/dDBP in SI were smaller than in control group respectively.Conclusions The results indicate that an inappropriately low nocturnal blood pressure,or an excessive fall in nocturnal blood pressure,is associated with lacunar infarct.It is necessary not only to controlhigh blood pressure but also to pay attention to circadian changes of blood pressure during the course of anti-hypertensive treatment.

  14. The usefulness of diffusion-weighted/fluid-attenuated inversion recovery imaging in the diagnostics and timing of lacunar and nonlacunar stroke

    Energy Technology Data Exchange (ETDEWEB)

    Witkowski, Grzegorz; Sienkiewicz-Jarosz, Halina [Institute of Psychiatry and Neurology, 1st Department of Neurology, Warsaw (Poland); Piliszek, Agnieszka; Ryglewicz, Danuta [Central Clinical Hospital of the Ministry of Interior, Department of Radiology, Warsaw (Poland); Skierczynska, Agnieszka; Poniatowska, Renata [Institute of Psychiatry and Neurology, Department of Radiology, Warsaw (Poland); Dorobek, Malgorzata; Filipek-Gliszczynska, Anna [Central Clinical Hospital of the Ministry of Interior, Department of Neurology, Warsaw (Poland); Walecki, Jerzy [Polish Academy of Science, Mossakowski Medical Research Centre, Warsaw (Poland)

    2014-10-15

    The DWI/FLAIR mismatch is a potential radiological marker for the timing of stroke onset. The aim of the study was to assess if the DWI/FLAIR mismatch can help to identify patients with both lacunar and nonlacunar acute ischemic stroke within 4.5 h of onset. A retrospective study was performed in which the authors analysed data from 86 ischemic lacunar and nonlacunar stroke patients with a known time of symptom onset, imaged within the first 24 h from stroke onset (36 patients <4.5 h, 14 patients 4.5-6 h, 15 patients 6-12 h, and 21 patients 12-24 h). Patients underwent the admission CT and MR scan. The presence of lesions was assessed in correlation with the duration of the stroke. The time from stroke onset to neuroimaging was significantly shorter in patients with an ischemic lesion visible only in the DWI (mean 2.78 h, n = 24) as compared to patients with signs of ischemia also in other modalities (mean 8.6 h, n = 62) (p = 0.0001, Kruskal-Wallis ANOVA). The DWI/FLAIR mismatch was characterised by a global sensitivity of 58 %, specificity 94 %, PPV 87.5 %, and NPV 76 % in identifying patients in the 4.5 h thrombolysis time window. For lacunar strokes (n = 20), these parameters were as follows: sensitivity 50 %, specificity 92.8 %, PPV 75 %, and NPV 81.2 %. The presence of acute ischemic lesions only in DWI can help to identify both lacunar and nonlacunar stroke patients who are in the 4.5 h time window for intravenous thrombolysis with high specificity. (orig.)

  15. The usefulness of diffusion-weighted/fluid-attenuated inversion recovery imaging in the diagnostics and timing of lacunar and nonlacunar stroke

    International Nuclear Information System (INIS)

    The DWI/FLAIR mismatch is a potential radiological marker for the timing of stroke onset. The aim of the study was to assess if the DWI/FLAIR mismatch can help to identify patients with both lacunar and nonlacunar acute ischemic stroke within 4.5 h of onset. A retrospective study was performed in which the authors analysed data from 86 ischemic lacunar and nonlacunar stroke patients with a known time of symptom onset, imaged within the first 24 h from stroke onset (36 patients <4.5 h, 14 patients 4.5-6 h, 15 patients 6-12 h, and 21 patients 12-24 h). Patients underwent the admission CT and MR scan. The presence of lesions was assessed in correlation with the duration of the stroke. The time from stroke onset to neuroimaging was significantly shorter in patients with an ischemic lesion visible only in the DWI (mean 2.78 h, n = 24) as compared to patients with signs of ischemia also in other modalities (mean 8.6 h, n = 62) (p = 0.0001, Kruskal-Wallis ANOVA). The DWI/FLAIR mismatch was characterised by a global sensitivity of 58 %, specificity 94 %, PPV 87.5 %, and NPV 76 % in identifying patients in the 4.5 h thrombolysis time window. For lacunar strokes (n = 20), these parameters were as follows: sensitivity 50 %, specificity 92.8 %, PPV 75 %, and NPV 81.2 %. The presence of acute ischemic lesions only in DWI can help to identify both lacunar and nonlacunar stroke patients who are in the 4.5 h time window for intravenous thrombolysis with high specificity. (orig.)

  16. Recurrence of lacunar stroke and blood pressure control. Kanagawa REALITY

    International Nuclear Information System (INIS)

    Information on the background and status of recurrence realities of lacunar infarction (LI) is still limited. We investigated 856 patients started to treat from 1997 to 2000, in whom a diagnosis of first-ever symptomatic LI was detected by MRI were enrolled, excluding possible cardiogenic embolic stroke or branch atheromatous disease using medical records in 14 institutions in Kanagawa, retrospectively. Recurrent cerebrovascular events (CVEs) occurred in 96 patients (11%) and the annual incidence was 4.8%. The mean systolic blood pressure (SBP) just before recurrence of CVEs was significantly higher than the mean SBP at final follow-up in recurrence-free patients (P<0.001). As the result of multivariate analysis performed after adjusting for following risk factors, antiplatelet therapy, a high SBP just before the end of follow-up, the presence of diabetes mellitus, and a modified Rankin scale≥5 were independent prognostic factors related to recurrence of CVEs. The recurrence rates of CVEs or LI were decreased by lowering of the SBP and diastolic blood pressure (DBP) just before the end of follow-up. Our analyses provide no evidence of a J-curve relationship between BP level and a recurrence after first-ever symptomatic LI. (author)

  17. Detection of lacunar infarction in brain CT-scans: No evidence of bias from accompanying patient information

    International Nuclear Information System (INIS)

    Interobserver agreement in assessing brain CT-scans is, in general, high. The extent, however, to which such agreement is caused by bias through knowledge of other clinical details remains uncertain. The hypothesis that observers are somehow prejudiced before assessing ambiguous, CT-scans in this particular situation was tested. Sixteen neurologists and 16 radiologists volunteered to interpret two ambiguous brain CT-scans, with regard to the presence or absence of a lacunar infarct in the region of the internal capsule. The scans were accompanied by 'patient' information that was or was not suggestive of a stroke. These scans were camouflaged by a variety of other scans, to be assessed in the same way, to mask the purpose of the study. I was assumed that the observers, in their assessments of the scans, would somehow let their ratings of the likelihood of a lacunar infarction in or near the internal capsule be subject to the accompanying information. Results showed lower ratings produced by neurologists (i.e., less likelihood of an infarction) than by radiologists in the majority of all assessments, but no bias by the accompanying information. (orig.)

  18. Lacunar Infarction Associated with Anabolic Steroids and Polycythemia: A Case Report

    Directory of Open Access Journals (Sweden)

    George W.J. Harston

    2014-02-01

    Full Text Available Lacunar infarction is traditionally ascribed to lipohyalinosis or microatheroma. We report the case of 40-year-old man, without traditional risk factors for ischemic stroke, who presented to the Emergency Department with recurrent episodes of transient right-sided weakness and paresthesia. Lacunar infarction was confirmed on diffusion-weighted MRI and blood tests showed a marked polycythemia. Quantitative magnetic resonance perfusion imaging demonstrated dramatically abnormal perfusion throughout both cerebral hemispheres, and transcranial Doppler revealed reduced cerebral artery velocities, both consistent with the proposed mechanism of hyperviscosity. His symptoms settled with treatment of the polycythemia and workup did not find another cause of ischemic stroke. We propose that hyperviscosity secondary to steroid-induced polycythemia caused ischemia in this case and not lipohyalinosis or microatheroma, to which lacunar disease is commonly attributed.

  19. Magnetic resonance imaging of lacunar infarcts in the basal ganglionic area

    International Nuclear Information System (INIS)

    During the previous 2 years, 88 patients have been diagnosed as having lacunar infarcts in the basal ganglioa ( a total of 157 lesions) on magnetic resonance imaging (MRI):42 patients had a single lesion and 46 patients had multiple lesions (2 lesions in 25 patients, 3 lesions in 14, and 4 or more lesions in 7). Seventy-seven lesions (49%) were smaller than 5 mm in diameter, and the others ranged from 5 mm to 15 mm. According to the regional relations to the internal capsule, the lesions were classified as lateral (57 lesions), anterior (36), superior (34), posterior (26), and inferior (4). Lesions of posterior, anterior, superior, and inferior types were associated with severer hemisparetic state, an abnormally slow gait, a sensory disturbance of numbness, and a depressive state, respectively. Forty five lesions (28%) were asymptomatic. Cat scanning failed to deliniate 47 lesions (30%) that were detected on MRI. Twenty three lesions were both asymptomatic and undistinguished on CT, which consisted of the superior type (10), anteior type (7), lateral type (5), and posterior type (one). Twenty four lesions were symptomatic, but were undistinguished on CT, suggesting that MRI is superior to CT in detecting the lacunar infarcts in the basal ganglionic area. Lacunar infarcts in both acute and chronic stages tended to be larger on T2-weighted images than T1-weighted images. In 7 patients who had neither history of hypertension, diabetes mellitus, or cardiac emboli nor CT evidence, MRI was capable of detecting lacunar infarcts. (N.K.)

  20. Contribution to the determination of the double angular and energy differential neutron albedo. Application to the propagation in lacunar medium

    International Nuclear Information System (INIS)

    This thesis deals with the neutrons propagation by reflection on the vacuum-matter interfaces of a lacunar medium, to control the direct irradiation risk. The more efficient method to simulate this propagation is the use of reflection coefficients (albedo). The first part of the work deals with the generation of albedo for various materials. The Monte Carlo method has been chosen and a new estimator has been developed and validated in the Monte Carlo transport code TRIPOLI4. This estimator is based on the neutrons transport simulation in the matter, to calculate in each collision point the double differential reflexions probability. The second part deals with the implementing of an interpolation module of the generated albedo in a library. These differential albedo of neutrons allow the study of the neutrons propagation by multi-reflections and the accurate calculation of the equivalent dose rate generated by the neutrons reflections. (A.L.B.)

  1. Evaluation of Vertical Lacunarity Profiles in Forested Areas Using Airborne Laser Scanning Point Clouds

    Science.gov (United States)

    Székely, B.; Kania, A.; Standovár, T.; Heilmeier, H.

    2016-06-01

    The horizontal variation and vertical layering of the vegetation are important properties of the canopy structure determining the habitat; three-dimensional (3D) distribution of objects (shrub layers, understory vegetation, etc.) is related to the environmental factors (e.g., illumination, visibility). It has been shown that gaps in forests, mosaic-like structures are essential to biodiversity; various methods have been introduced to quantify this property. As the distribution of gaps in the vegetation is a multi-scale phenomenon, in order to capture it in its entirety, scale-independent methods are preferred; one of these is the calculation of lacunarity. We used Airborne Laser Scanning point clouds measured over a forest plantation situated in a former floodplain. The flat topographic relief ensured that the tree growth is independent of the topographic effects. The tree pattern in the plantation crops provided various quasi-regular and irregular patterns, as well as various ages of the stands. The point clouds were voxelized and layers of voxels were considered as images for two-dimensional input. These images calculated for a certain vicinity of reference points were taken as images for the computation of lacunarity curves, providing a stack of lacunarity curves for each reference points. These sets of curves have been compared to reveal spatial changes of this property. As the dynamic range of the lacunarity values is very large, the natural logarithms of the values were considered. Logarithms of lacunarity functions show canopy-related variations, we analysed these variations along transects. The spatial variation can be related to forest properties and ecology-specific aspects.

  2. Organ and tissue level properties are more sensitive to age than osteocyte lacunar characteristics in rat cortical bone

    Directory of Open Access Journals (Sweden)

    Nina Kølln Wittig

    2016-06-01

    Full Text Available Modeling and remodeling induce significant changes of bone structure and mechanical properties with age. Therefore, it is important to gain knowledge of the processes taking place in bone over time. The rat is a widely used animal model, where much data has been accumulated on age-related changes of bone on the organ and tissue level, whereas features on the nano- and micrometer scale are much less explored. We investigated the age-related development of organ and tissue level bone properties such as bone volume, bone mineral density, and load to fracture and correlated these with osteocyte lacunar properties in rat cortical bone. Femora of 14 to 42-week-old female Wistar rats were investigated using multiple complementary techniques including X-ray micro-computed tomography and biomechanical testing. The body weight, femoral length, aBMD, load to fracture, tissue volume, bone volume, and tissue density were found to increase rapidly with age at 14–30 weeks. At the age of 30–42 weeks, the growth rate appeared to decrease. However, no accompanying changes were found in osteocyte lacunar properties such as lacunar volume, ellipsoidal radii, lacunar stretch, lacunar oblateness, or lacunar orientation with animal age. Hence, the evolution of organ and tissue level properties with age in rat cortical bone is not accompanied by related changes in osteocyte lacunar properties. This suggests that bone microstructure and bone matrix material properties and not the geometric properties of the osteocyte lacunar network are main determinants of the properties of the bone on larger length scales.

  3. The prevalence of lacunar infarct decreases with aging in the elderly: a case-controlled analysis

    Directory of Open Access Journals (Sweden)

    Cai Z

    2016-05-01

    Full Text Available Zhiyou Cai,1 Wenbo He,1 Chuan-yong Peng,2 Jin Zhou,2 Qi-lan Xu,2 Zong-shan Wu2 1Department of Neurology, Renmin Hospital, Hubei University of Medicine, Shiyan Renmin Hospital, Shiyan, Hubei Province, 2The Examination Center of Magnetic Resonance Imaging, the Lu’an Affiliated Hospital of Anhui Medical University, Lu’an People’s Hospital, Lu’an, Anhui Province, People’s Republic of China Background and purpose: Lacunar infarct (LI is well known as a heterogeneous primary disorder of cerebral small vessel. Compelling results have demonstrated that age is a risk factor to the prevalence of LI. However, the relationship between age and the prevalence of LI remains obscure. It is essential to note the relationship between age and the prevalence of LI through more clinical data. Methods: A total of 3,500 patients were included in the case-controlled study. All data were collected from the Examination Center of Magnetic Resonance Imaging, Lu’an People’s Hospital from January 2014 to December 2015. A primary discharge diagnosis of LI was done, and all subjects were evaluated as retrospective data. The relationship between the risk factors and the prevalence of diabetes and the relationship between age and the prevalence of diabetes was analyzed. A chi-square test was used to analyze the associations between different variables. A one-way analysis of variance was used to test the equality of three or more means at one time by using variances. Statistical significance was defined as a P-value of <0.05. Results: The one-way analysis of variance demonstrated that the prevalence of LI increased with age before 60 years and decreased with age after 69 years. The same results were found in both the male and the female subjects. These results showed that the age-related risk factors (hypertension, diabetes, cerebral infarct, cardiovascular diseases, smoking, and drinking have no relationship with the prevalence of LI on the basis of age. There is

  4. Xueshuantong improves cerebral blood perfusion in elderly patients with lacunar infarction

    Institute of Scientific and Technical Information of China (English)

    Qifeng Gui; Yunmei Yang; Shihong Ying; Minming Zhang

    2013-01-01

    A total of 64 patients with acute lacunar infarction were enrolled within 24 hours of onset. The patients received conventional therapy (antiplatelet drugs and hypolipidemic drugs) alone or conventional therapy plus 450 mg Xueshuantong once a day. The main ingredient of the Xueshuantong lyophilized powder used for injection was Panax notoginseng saponins. Assessments were made at admission and at discharge using the National Institutes of Health Stroke Scale, the Activity of Daily Living and the Mini-Mental State Examination. Additionally, the relative cerebral blood flow, relative cerebral blood volume and relative mean transit time in the region of interest were calculated within 24 hours after the onset of lacunar infarction, using dynamic susceptibility contrast magnetic resonance perfusion imaging technology. Patients underwent a follow-up MRI scan after 4 weeks of treatment. There was an improvement in the Activity of Daily Living scores and a greater reduction in the scores on the National Institutes of Health Stroke Scale in the treatment group than in the control group. However, the Mini-Mental State Examination scores showed no significant differences after 4 weeks of treatment. Compared with the control group, the relative cerebral blood flow at discharge had increased and showed a greater improvement in the treatment group. Furthermore, there was a reduction in the relative mean transit time at discharge and the value was lower in the treatment group than in the control group. The experimental findings indicate that Xueshuantong treatment improves neurological deficits in elderly patients with lacunar infarction, and the mechanism may be related to increased cerebral perfusion.

  5. Capsular warning syndrome and crescendo lacunar strokes after atherosclerotic stenosis of the recurrent artery of Heubner.

    Science.gov (United States)

    Cohen, José E; Rabinstein, Alejandro; Gomori, John M; Leker, Ronen R

    2012-12-01

    The stereotype of repetitive transient cerebral ischemia causing unilateral motor, sensory, or sensorimotor deficits that simultaneously affect the face, arm, and leg, clinically localized to the internal capsule, fits with the description of capsular warning syndrome (CWS). A high proportion of individuals with these symptoms develop subsequent capsular stroke, despite various proposed preventative measures. It has been postulated that the mechanism for such strokes is that of small-vessel single-penetrator disease. We present a patient with repetitive CWS intermingled with crescendo capsular strokes secondary to recurrent artery of Heubner disease. This report causally links CWS-crescendo lacunar strokes and Heubner artery atherosclerotic disease (intracranial branch atheromatous disease).

  6. Clinical Study on the Treatment of Lacunar Infarction of Qi Deficiency and Collateral Stasis Type by Quyu Buqi Decoction%祛瘀补气汤治疗气虚络瘀型腔隙性脑梗死临床研究

    Institute of Scientific and Technical Information of China (English)

    王志理

    2012-01-01

    目的:探讨祛瘀补气汤治疗气虚络瘀型腔隙性脑梗死的临床疗效.方法:腔隙性脑梗死(气虚络瘀型)患者165例,采用随机数字表法,依据就诊先后顺序分为治疗组105例,对照组60例.所有患者治疗期间均给予基础治疗.对照组采用血塞通注射液400 mg加入体积分数5%葡萄糖注射液250 mL中(高血糖患者使用体积分数0.9%生理盐水250 mL)缓慢静脉滴注,每日1次.治疗组采用祛瘀补气汤(方药组成:黄芪60 g,当归15 g,赤芍15 g,川芎10 g,桃仁10 g,红花15 g,水蛭10 g,地龙10 g,石菖蒲15 g,鸡血藤30 g,杜仲15 g,牛膝15 g)治疗,每日1剂,水煎服.两组均14 d为1个疗程,2个疗程后统计疗效.结果:对照组60例,痊愈24例,显效15例,有效14例,无效7例,有效率为88.33%;治疗组105例,痊愈67例,显效25例,有效10例,无效3例,有效率为97.14%.两组有效率比较,x2=5.205,P=0.023<0.05,差异有统计学意义.结论:祛瘀补气汤治疗气虚络瘀型腔隙性脑梗死临床疗效显著.%Objective:To discuss the clinical effects of Quyu Buqi Decoction on the treatment of lacunar infarction of qi deficiency and collateral stasis type. Methods: 165 patients of lacunar infarction (with the type of qi deficiency and collateral stasis) were divided into the treatment group(105 cases) and the control group(60 cases) by the method of random number table according to the sequence of treatment. All patients were given basic treatment during treatment. Patients in the control group were treated by slow intravenous drip of Xueshuantong injection plus 250 mL of 5% of GS(replaced by 250 mL of NS for patients of hyperglycemia) ,once a day. Patients in the treatment group were treated by Quyu Buqi Decoction( Recipe components: Astragalus 60 g, Angelica 15 g.red peony root 15 g,hemlock parsley 10 g, walnuts 10 g,safflower 15g,the leech 10 g,earthworm 10 g,the iris 15 g,the Millettia 30 g,the eucommia 15 g,Achyran-thes 15 g) for resolving stasis

  7. Correlation study between cerebral microbleeds and early neurological deterioration in patients with first-onset acute lacunar stroke%首发急性腔隙性脑梗死患者脑微出血与早期神经功能恶化的关联研究

    Institute of Scientific and Technical Information of China (English)

    韩忠奎; 任明山; 夏元亮; 锁六军

    2015-01-01

    Objective The predictive indexes which affect early neurological deterioration ( END) of patients with acute la-cunar stroke still remain unclear .The purpose of the article was to investigate the correlation between the location and numbers of cere -bral microbleeds (CMBs) and END in patients with first-onset lacunar stroke. Methods 217 patients with acute lacunar stroke hos-pitalized in Anhui Provincial Hospital within 24 hours after occurrence from Mar 2009 to May 2012 were prospectively enrolled .All pa-tients underwent susceptibility-weighted imaging MRI right after admission , followed by the investigation on the relationship of the loca-tion and numbers of CMBs and END . Results END occurred in 76 (35.0%) patients.Among these patients, there were 33 positive cases with CMBs (43.3%).There were no significant difference in END incidence between positive group and negative group (P=0.173).In the comparison of the numbers of CMBs foci , patients with more than 5 foci were more prone to END (P=0.005).Logistic regression analysis showed there was relation between CMBs foci numbers>5 and END (OR=3.14, 95% CI: 1.22 ~8.13), and there was no relation between CMBs foci numbers≤5 and END ( OR=1.12, 95%CI:0.53~2.37)as to CMBs negative patients.No signifi-cant relationship was found in CMBs location and END occurrence ( P>0.05). Conclusion The distribution of CMBs foci has nothing to do with early neurological fluctuation .However , more than 5 CMBs foci might be the independent prediction cause of END .%目的:急性腔隙性脑梗死患者早期神经功能恶化( early neurological deterioration , END)的影响预测指标目前尚不明确。文中拟探讨首发急性腔隙性脑梗死患者脑微出血病灶的位置、数量与END的联系。方法选取2009年3月至2012年5月发病24 h内收治于安徽省立医院神经内科的急性腔隙性脑梗死患者217例。所有患者完成磁共振磁敏感成像检查,探讨微出血病灶的位置

  8. Validity of apparent diffusion coefficient hyperpolarized 3He-MRI using MSCT and pulmonary function tests as references

    DEFF Research Database (Denmark)

    Diaz, Sandra; Casselbrant, Ingrid; Piitulainen, Eeva;

    2008-01-01

    PURPOSE: To compare apparent diffusion coefficient (ADC) measurements from hyperpolarized (HP) helium ((3)He)-magnetic resonance imaging (MRI) with quantitative data from multislice Computed Tomography (CT) (MSCT) of the whole lungs and pulmonary function tests (PFT). MATERIALS AND METHODS: Twenty...

  9. Multifractal analysis and lacunarity spectrum of the galaxies of the ninth Sloan Digital Sky Survey (SDSS) data release

    CERN Document Server

    Chacón-Cardona, César A

    2012-01-01

    In this work, we develop a statistical analysis of the large-scale clustering of matter in the Universe from the fractal point of view using galaxies from the Ninth Sloan Digital Sky Survey (SDSS) Data Release (DR9). From the total set of galaxies, a magnitude-limited sample of galaxies with redshifts in the range 0 < z < 0.15 was created. The sample covers the largest completely connected area of the celestial sphere within the catalogue, with limits in right ascension from 120 to 240 degrees and declination from 0 to 60 degrees, which is a region that includes the largest galactic samples that have been studied from the fractal viewpoint to date. The sample contains 164,168 galaxies. Using the sliding-window technique, the multifractal dimension spectrum and its dependence on radial distance are determined. This generalisation of the concept of fractal dimension is used to analyse large-scale clustering of matter in complex systems. Likewise, the lacunarity spectrum, which is a quantity that complemen...

  10. Experimental determination of the permeability in the lacunar-canalicular porosity of bone.

    Science.gov (United States)

    Gailani, Gaffar; Benalla, Mohammed; Mahamud, Rashal; Cowin, Stephen C; Cardoso, Luis

    2009-10-01

    Permeability of the mineralized bone tissue is a critical element in understanding fluid flow occurring in the lacunar-canalicular porosity (PLC) compartment of bone and its role in bone nutrition and mechanotransduction. However, the estimation of bone permeability at the tissue level is affected by the influence of the vascular porosity in macroscopic samples containing several osteons. In this communication, both analytical and experimental approaches are proposed to estimate the lacunar-canalicular permeability in a single osteon. Data from an experimental stress-relaxation test in a single osteon are used to derive the PLC permeability by curve fitting to theoretical results from a compressible transverse isotropic poroelastic model of a porous annular disk under a ramp loading history (2007, "Compressible and Incompressible Constituents in Anisotropic Poroelasticity: The Problem of Unconfined Compression of a Disk," J. Mech. Phys. Solids, 55, pp. 161-193; 2008, "The Unconfined Compression of a Poroelastic Annular Cylindrical Disk," Mech. Mater., 40(6), pp. 507-523). The PLC tissue intrinsic permeability in the radial direction of the osteon was found to be dependent on the strain rate used and within the range of O(10(-24))-O(10(-25)). The reported values of PLC permeability are in reasonable agreement with previously reported values derived using finite element analysis (FEA) and nanoindentation approaches. PMID:19831477

  11. Clinically unsuspected intracranial hemorrhage as revealed by MR imaging in patients with multiple lacunar infarcts

    International Nuclear Information System (INIS)

    Between April 1987 and March 1989, high-field MR imaging was performed in 33 consecutive patients with multiple lacunar infarctions. Although they had no history of hemorrhagic stroke, 17 patients had low-signal intensity areas on T2-weighted images. The low-signal intensity areas were divided into two types: (I) areas more than 1 cm in the maximum diameter (9 patients) and (II) areas measuring as small as 2-3 mm in diameter (8 patients). Three patients had both types of low-signal intensity. For type I, the putamen, thalamus, and right temporal white matter were shown as low-signal intensities in 6, 2, and one patient, respectively. Low-signal intensity for type II was restricted to areas in or near the infarct lesions. Lesions of the putamen or thalamus, as shown in the group of type I, were considered to represent chronic hematoma probably due to previously undiagnosed cerebral hemorrhage. The group of type II seemed to have hemorrhagic infarction. A mean age of the onset of initial symptoms was 55.9 years in the group of type I and 58.6 years in the group of type II. Regarding blood pressure, there was no significant difference between the groups. T2-weighted imaging showed a tendency for low-signal intensity areas in younger patients with hypertension. Thus, MRI imaging may be useful in clinically diagnosing unsuspected intracranial hemorrhage in patients with multiple lacunar infarctions. (N.K.)

  12. Clinically unsuspected intracranial hemorrhage as revealed by MR imaging in patients with multiple lacunar infarcts

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Shuji; Kawamura, Junichiro; Nakamura, Michikazu; Yamamoto, Toru; Miki, Yukio (Tenri Hospital, Nara (Japan))

    1990-07-01

    Between April 1987 and March 1989, high-field MR imaging was performed in 33 consecutive patients with multiple lacunar infarctions. Although they had no history of hemorrhagic stroke, 17 patients had low-signal intensity areas on T2-weighted images. The low-signal intensity areas were divided into two types: (I) areas more than 1 cm in the maximum diameter (9 patients) and (II) areas measuring as small as 2-3 mm in diameter (8 patients). Three patients had both types of low-signal intensity. For type I, the putamen, thalamus, and right temporal white matter were shown as low-signal intensities in 6, 2, and one patient, respectively. Low-signal intensity for type II was restricted to areas in or near the infarct lesions. Lesions of the putamen or thalamus, as shown in the group of type I, were considered to represent chronic hematoma probably due to previously undiagnosed cerebral hemorrhage. The group of type II seemed to have hemorrhagic infarction. A mean age of the onset of initial symptoms was 55.9 years in the group of type I and 58.6 years in the group of type II. Regarding blood pressure, there was no significant difference between the groups. T2-weighted imaging showed a tendency for low-signal intensity areas in younger patients with hypertension. Thus, MRI imaging may be useful in clinically diagnosing unsuspected intracranial hemorrhage in patients with multiple lacunar infarctions. (N.K.).

  13. Evaluation of 3D tensor tractography of pyramidal tract depicted by 3T MRI in patients with lacunar infarcts. For prediction of motor function outcome

    International Nuclear Information System (INIS)

    3D tensor tractography (DTT) has been applied to central nervous system (CNS) diseases to depict neuronal fibers. In this study with 3 tesla MRI, we have evaluated DTT to predict outcome of motor function in patients with lacunar infarcts. Fifteen patients with New lacunar infarcts, underwent DTTs with at least one in the acute (mean 1.4 days) and another in the subacute phase (mean 18.7 days). Patients were separated to 2 groups, recovery and non-recovery. Patients in former group had almost complete recovery in motor function 3 month later, while those to latter had a residual hemiparesis. Motor function was assessed with MMT score, which was uniquely stratefied into 12 levels by a modified MMT (manual muscle testing) protocol. DTT was implemented with 3 tesla MRI (Signa Excite; GE) and analyzed with dTV. IISR which was produced by the Department of Radiology, Tokyo University. The pyramidal tract was delineated by setting each region of interest (ROI), with the cerebral peduncle as the seed point and the motor cortex as the target point. The number of pyramidal fibers was identified as drawn lines obtained from a result display. The ratio of the number of fibers (RF) was calculated based on the number of fibers in the injured side relative to the number of fibers in the intact side x 100. In acute phase mean RFs the recovery (70.8±21.6%) and non-recovery (63.5±23.4%) groups were not significantly different. RF of recovery group in subacute phase was 100.5±28.3%, which was significantly higher with that in acute phase, meanwhile there was no significance difference between RFs of non-recovery group in two phases. In addition there was a significant correlation (R2=0.89) between MMT score 3 month later and RF in subacute phase in all patients group. There seems to be a correlation between long-term recovery of motor function and increased numbers in pyramidal fibers defected by DTT. Therefore, DTT may have a potential use in predicting the outcome of patients

  14. 腔隙性卒中后疲劳与认知障碍和抑郁的相关性:回顾性病例系列研究%Correlation between fatigue and cognitive impairment and depression in patients with lacunar stroke: a retrospective case series study

    Institute of Scientific and Technical Information of China (English)

    王明红; 艾清龙

    2012-01-01

    目的 探讨腔隙性卒中后疲劳与认知障碍和抑郁的相关性.方法 纳入2009年9月至2010年11月期间住院的103例腔隙性卒中患者,采用疲劳量表-14(Fatigue Scale,FS-14)、疲劳严重程度量表(Fatigue Severity Scale,FSS-9)评价卒中后疲劳,简易精神状态检查量表(Mini-Mental State Examinat ion,MMSE)和蒙特利尔认知评估量表(Montreal Cognitive Assessment,MoCA)评价认知功能,抑郁自评量表(Self-Rating Depression Scale,SDS)和汉密尔顿抑郁量表(Hamilton Depression Scale,HAMD)评价抑郁情况.结果 通过不同量表评定,分别有34例(33.01%) (FSS-9)和45例(43.69%)(FS-14)存在疲劳.在根据FSS-9评分确定的34例疲劳患者中,有20例存在认知损害,26例存在抑郁,16例同时存在认知损害和抑郁.Pearson相关分析显示,FS-14评分与MMSE评分(r=-0.307,P =0.002)和MoCA评分(r=-0.457,P=0.000)呈显著负相关,而与SDS评分(r=0.368,P=0.000)和HAMD评分(r=0.526,P=0.000)呈显著正相关;FSS-9评分亦与MMSE评分(r=-0.292,P=0.003)和MoCA评分(r=-0.340,P=0.000)呈显著负相关,而与SDS评分(r=0.403,P=0.000)和HAMD评分(r=0.564,P=0.000)呈显著正相关.结论 腔隙性卒中患者的疲劳、认知损害和抑郁发生率均较高,疲劳与认知损害和抑郁之间存在一定的相关性.%Objective To investigate the correlation between fatigue and cognitive impairment and depression after lacunar stroke.Methods A total of 103 patients with lacunar infarction admitted from September 2009 to November 2010 were enrolled.Post-stroke fatigue was evaluated with the Fatigue Scale (FS-14) and the Fatigue Severity Scale (FSS-9); cognitive function was evaluated with the mini-mental state examination (MMSE) and the Montreal cognitive assessment (MoCA); and depression was evaluated with the self-rating depression scale (SDS) and the Hamilton Depression Rating Scale (HAMD).Results There were 34 patients (33.01%) (FSS-9) and 45 patients (43.69%) (FS-14) had fatigue

  15. Carbonic anhydrase levels and internal lacunar CO/sub 2/ concentrations in aquatic macrophytes

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, C.I.

    1979-01-01

    Carbonic anhydrase levels were examined in a variety of aquatic macrophytes from different habitats. In general, carbonic anhydrase levels increased across the habitat gradient such that activities were low in submersed aquatic macrophytes and high in emergent macrophytes with floating-leaved and free-floating plants exhibiting intermediate activities. Internal lacunar CO/sub 2/ concentrations were analyzed in relation to carbonic anhydrase activities. There was no correlation between these two parameters. Internal CO/sub 2/ concentrations ranged from low to high in submersed macrophytes, but were low in floating-leaved and emergent macrophytes. The observed internal CO/sub 2/ concentrations are discussed in relation to the individual morphologies of the plants and the environments in which they occurred.

  16. Deterioration of pre-existing hemiparesis brought about by subsequent ipsilateral lacunar infarction.

    Science.gov (United States)

    Ago, T; Kitazono, T; Ooboshi, H; Takada, J; Yoshiura, T; Mihara, F; Ibayashi, S; Iida, M

    2003-08-01

    Mechanisms of post-stroke recovery are still poorly understood. Recent evidence suggests that cortical reorganisation in the unaffected hemisphere plays an important role. A 59 year old man developed a small lacunar infarct in the left corona radiata, which then caused marked deterioration in a pre-existing left hemiparesis that had resulted from an earlier right putaminal haemorrhage. Functional magnetic resonance imaging showed that the paretic left hand grip activated the ipsilateral left motor areas, but not the right hemispheric motor areas. This suggests that partial recovery of the left hemiparesis had been brought about by cortical reorganisation of the left hemisphere and intensification of the uncrossed corticospinal tract. The subsequent small infarct may have damaged the uncrossed tract, thereby causing the pre-existing hemiparesis to deteriorate even further.

  17. Correlation between cerebral microbleeds and cognitive impairment in patients with lacunar infarction and/or leukoaraiosis: a retrospective case series study%腔隙性梗死和(或)脑白质疏松患者脑微出血与认知损害的相关性:回顾性病例系列研究

    Institute of Scientific and Technical Information of China (English)

    詹羽; 刘煜敏

    2015-01-01

    Objective To detect the distribution of cerebral microbleeds (CMBs) in patients with lacunar infarction (LI) and/or leukoaraiosis (LA) and to analyze the correlation between the CMB related risk factors and cognitive impairment.Methods Thirty-eight patients with LI and/or LA were divided into either a CMB group or a non-CMB group according to the findings of susceptibility weighted imaging.The number of CMB lesions was recorded.Mini-mental state examination (MMSE) and Montreal cognitive assessment (MoCA) were used to conduct cognitive function tests,and the patients were also divided into a cognitive impairment group and a non-cognitive impairment group according to the MoCA scores.The demographic and clinical data in each group were compared.The independent risk factors for CMBs and cognitive impairment were identified.Results Thirteen patients had 58 CMBs in the CMB group.Their distributions were as follows:36 CMBs in basal ganglia and thalamus,14 in cortical and subcortical regions,3 in brain stem,and 5 in cerebellum.There were 25 patients in the non-CBM group,26 in the cognitive impairment group,and 12 in the non-cognitive impairment group.There were significant differences in age and the proportions of hypertension,taking antithrombotic drugs and the patients with LA between the CMB group and the non-CMB group (all P < 0.05).Multivariable logistic regression analysis showed that only age was an independent risk factor for CMBs (odds ratio 1.103,95% confidence interval 1.034-1.454; P =0.045).MMSE (26.92±2.87vs.29.00± 1.44; t=2.452,P=0.027) and MoCA (21.62±3.36vs.25.04 ± 2.59; t =-3.493,P =0.001) scores in the CMB group were significantly lower than those in the non-CMB group.There was only significant difference in the number of CMBs between the cognitive impairment group and the non-cognitive impairment group (2.08-± 3.64 vs.0.33 ±0.78; t =-1.629,P =0.010).Multivariate logistic regression analysis showed that only the number of CMBs was an

  18. Immobilization and long-term recovery results in large changes in bone structure and strength but no corresponding alterations of osteocyte lacunar properties

    DEFF Research Database (Denmark)

    Bach-Gansmo, Fiona Linnea; Wittig, Nina Kølln; Brüel, Annemarie;

    2016-01-01

    whether osteocyte lacunar properties change during immobilization and subsequent recovery. A rat cortical bone model with negligible Haversian remodeling effects was used, with temporary immobilization of one hindlimb induced by botulinum toxin. Several complementary techniques covering multiple length...

  19. 腔隙性脑梗死在原发性高血压患者危险分层中的意义%The significance of lacunar infarction in the risk stratification of essential hyertension

    Institute of Scientific and Technical Information of China (English)

    姚保明

    2011-01-01

    Objective: To study the significance of lacunar infarction in the risk stratification of essential hypertension. Methods: 214 patients with essential hypertension were divided into CLI group (lacunar infarction group), ACC group (related clinical conditions group) and TOD group (target organ damage group), then the damage degree of heart, renal and fundus of the three groups were compared. Results: The damage degree of heart, renal and fundus between CLI group and ACC group showed significant difference (ρ<0.01), the damage degree of heart, renal and fundus between CLI group and TOD group showed no significant difference (ρ>0.05). Conclusion: The lacunar infarction is index of risk stratification of essential hypertension, it shows the damage of heart, renal and fundus, the degree is similar to TOD, and should be the classification of TOD.%目的:探讨腔隙性脑梗死在原发性高血压危险分层中的意义.方法:241例原发性高血压患者被分为CLI组(腔隙性脑梗死组)、ACC组(相关临床情况组)和TOD组(靶器官损害组),比较三组间心、肾、眼底损害程度.结果:CLI组与ACC组间的心、肾及眼底损害程度比较,差异有统计学意义(P<0.01),CLI组与TOD组比较,差异无统计学意义(P>0.05).结论:腔隙性脑梗死作为原发性高血压危险分层中的指标,提示患者出现心、肾、眼底损害,其程度与TOD组相似,宜归为TOD组.

  20. Maximum entropy, fractal dimension and lacunarity in quantification of cellular rejection in myocardial biopsy of patients submitted to heart transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Neves, L A [Universidade Estadual Paulista, IGCE, DEMAC, Rio Claro, SP (Brazil); Oliveira, F R; Peres, F A [Faculdade de Tecnologia de Sao Jose do Rio Preto, Sao Jose do Rio Preto, SP (Brazil); Moreira, R D; Moriel, A R; De Godoy, M F [Faculdade de Medicina de Sao Jose do Rio Preto, FAMERP, Sao Jose do Rio Preto, SP (Brazil); Murta Junior, L O, E-mail: laneves@rc.unesp.br [Universidade de Sao Paulo, FFCLRP, Depto Computacao e Matematica, Ribeirao Preto (Brazil)

    2011-03-01

    This paper presents a method for the quantification of cellular rejection in endomyocardial biopsies of patients submitted to heart transplant. The model is based on automatic multilevel thresholding, which employs histogram quantification techniques, histogram slope percentage analysis and the calculation of maximum entropy. The structures were quantified with the aid of the multi-scale fractal dimension and lacunarity for the identification of behavior patterns in myocardial cellular rejection in order to determine the most adequate treatment for each case.

  1. Spatial dispersion and clustering of soil structure through lacunarity of X-ray CT images of soil macropore volumes

    Science.gov (United States)

    San José Martínez, Fernando; Caniego, Javier; García-Gutiérrez, Carlos

    2016-04-01

    Lacunarity can be seen as a scale dependent measure of heterogeneity or texture ―in terms of image analysis― that was first introduced to quantify different patterns of dispersion and clustering that display geometrical objects with the same fractal dimension. Notwithstanding, lacunarity functions have been revealed as means to measure the deviation of object's geometrical structure from translational invariance beyond self-similarity and fractal geometry. In this work, we will explore how lacunarity quantifies different patterns of dispersion and clustering of different geometrical structures of soil macropore volumes imaged by X-ray computed tomography. Samples extracted from columns were collected at the experimental farm "Finca La Grajera" in La Rioja (Spain), property of La Rioja Regional Government (northern Spain). The vineyard selected was established in 1996. During the 1996 to 2004 period, the soil management was conventional tillage. Before the vineyard was established in 1996, a pasture-legume-cereal rotation was used. In 2004 an experiment was established with different types of soil cover management in between. On December 2010 columns were extracted vertically by percussion drilling between rows of the vineyard.

  2. Assessment of diffusional anisotropy of the corpus callosum in patients with multiple lacunar infarcts. Relationship between the apparent diffusion coefficient ratio and global cognitive impairment

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, Makiko; Hayashi, Hiromitsu; Amano, Yasuo; Takagi, Ryo; Nakahara, Madoka; Kumazaki, Tatsuo [Nippon Medical School, Tokyo (Japan); Cho, Keiichi; Okada, Susumu

    1998-06-01

    The purpose of the present study is to evaluate diffusional anisotropy of white matter in patients with multiple lacunar infarcts using diffusion-weighted echo-planar imaging (DW-EPI), and to examine the relationship between diffusional anisotropy and global cognitive ability as assessed by the mini-mental status examination (MMSE). In particular, we focused on the parameter changes for the corpus callosum as a marker for disconnection of the associative cortices. Twenty-nine patients divided into 2 cognitive level groups (low MMSE, n=16; high MMSE, n=13) and 8 normal controls were examined with a GE 1.5 T Horizon system. Three series of DW-EPI images were obtained using the following epidw{sub g}{center_dot}psd{sup TM} sequence: TR/TE=6500/120 ms, single shot, 6.5 mm slice thickness and 1.5 mm gap transaxial sections of the whole brain, with b-factors of 0 and 710 along each x- and y-axial direction. The parametric maps for apparent diffusion coefficient (ADC) in each direction, ADC(x) and ADC(y), and their rate map (ADC rate=ADC(x)/ADC(y)) were created on a pixel-by-pixel basis. ROI data were extracted from images of the corpus callosum and bilateral optic radiata. As a result, the ADC(x) was markedly larger for corpus callosum than that for optic radiata, whereas the ADC(y) showed an inverse trend, attributable to regional differences of diffusional anisotropy. In corpus callosum, however, the ADC(y) values were observed to increase with the level of disease severity, resulting in a decrease of the ADC rate. Notably, there was a significant difference between the three groups for callosal genu, with a slight positive correlation between the ADC rate and the MMSE scores. Our study suggests that a relationship exists between the reduction of diffusional anisotropy in callosal genu and the global cognitive impairment seen in patients with multiple lacunar infarcts. (K.H.)

  3. Histomorphometric, fractal and lacunarity comparative analysis of sheep (Ovis aries), goat (Capra hircus) and roe deer (Capreolus capreolus) compact bone samples.

    Science.gov (United States)

    Gudea, A I; Stefan, A C

    2013-08-01

    Quantitative and qualitative studies dealing with histomorphometry of the bone tissue play a new role in modern legal medicine/forensic medicine and archaeozoology nowadays. This study deals with the differences found in case of humerus and metapodial bones of recent sheep (Ovis aries), goat (Capra hircus) and roedeer (Capreolus capreolus) specimens, both from a qualitative point of view, but mainly from a quantitative perspective. A novel perspective given by the fractal analysis performed on the digital histological images is approached. This study shows that the qualitative assessment may not be a reliable one due to the close resemblance of the structures. From the quantitative perspective (several measurements performed on osteonal units and statistical processing of data),some of the elements measured show significant differences among 3 species(the primary osteonal diameter, etc.). The fractal analysis and the lacunarity of the images show a great deal of potential, proving that this type of analysis can be of great help in the separation of the material from this perspective. PMID:24068686

  4. Organ and tissue level properties are more sensitive to age than osteocyte lacunar characteristics in rat cortical bone

    DEFF Research Database (Denmark)

    Wittig, Nina; Bach-Gansmo, Fiona Linnea; Birkbak, Mie Elholm;

    2016-01-01

    Modeling and remodeling induce significant changes of bone structure and mechanical properties with age. Therefore, it is important to gain knowledge of the processes taking place in bone over time. The rat is a widely used animal model, where much data has been accumulated on age-related changes...... orientation with animal age. Hence, the evolution of organ and tissue level properties with age in rat cortical bone is not accompanied by related changes in osteocyte lacunar properties. This suggests that bone microstructure and bone matrix material properties and not the geometric properties...

  5. Modeling fluorescence recovery after photobleaching in loaded bone: potential applications in measuring fluid and solute transport in the osteocytic lacunar-canalicular system.

    Science.gov (United States)

    Zhou, Xiaozhou; Novotny, John E; Wang, Liyun

    2008-12-01

    Solute transport through the bone lacunar-canalicular system is essential for osteocyte viability and function, and it can be measured using fluorescence recovery after photobleaching (FRAP). The mathematical model developed here aims to analyze solute transport during FRAP in mechanically loaded bone. Combining both whole bone-level poroelasticity and cellular-level solute transport, we found that load-induced solute transport during FRAP is characterized by an exponential recovery rate, which is determined by the dimensionless Strouhal (St) number that characterizes the oscillation effects over the mean flows, and that significant transport occurs only for St values below a threshold, when the solute stroke displacement exceeds the distance between the source and sink (the canalicular length). This threshold mechanism explains the general flow behaviors such as increasing transport with increasing magnitude and decreasing frequency. Mechanical loading is predicted to enhance transport of all tracers relative to diffusion, with the greatest enhancement for medium-sized tracers and less enhancement for small and large tracers. This study provides guidelines for future FRAP experiments, based on which the model can be used to quantify bone permeability, solute-matrix interaction, and flow velocities. These studies should provide insights into bone adaptation and metabolism, and help to treat various bone diseases and conditions. PMID:18810639

  6. The use of fractal dimension and lacunarity in the characterization of mast cell degranulation in rainbow trout (Onchorhynchus mykiss).

    Science.gov (United States)

    Manera, M; Dezfuli, B S; Borreca, C; Giari, L

    2014-11-01

    Fractal analysis is a reliable method for describing, summarizing object complexity and heterogeneity and has been widely used in biology and medicine to deal with scale, size and shape management problems. The aim of present survey was to use fractal analysis as a complexity measure to characterize mast cells (MCs) degranulation in a rainbow trout ex vivo model (isolated organ bath). Compound 48/80, a condensation product of N-methyl-p-methoxyphenethylamine with formaldehyde, was adopted as MCs degranulation agent in trout intestinal strips. Fractal dimension (D), as a measure of complexity, 'roughness' and lacunarity (λ), as a measure of rotational and translational invariance, heterogeneity, in other words, of the texture, were compared in MCs images taken from intestinal strips before and after compound 48/80 addition to evaluate if and how they were affected by degranulation. Such measures were also adopted to evaluate their discrimination efficacy between compound 48/80 degranulated group and not degranulated group and the results were compared with previously reported data obtained with conventional texture analysis (image histogram, run-length matrix, co-occurrence matrix, autoregressive model, wavelet transform) on the same experimental material. Outlines, skeletons and original greyscale images were fractal analysed to evaluate possible significant differences in the measures values according to the analysed feature. In particular, and considering outline and skeleton as analysed features, fractal dimensions from compound 48/80 treated intestinal strips were significantly higher than the corresponding untreated ones (paired t and Wilcoxon test, p fractal dimension and lacunarity values registered according to the analysed feature (greyscale obtained values were, on average, lower than those obtained from outlines and skeletons; General Linear Model, p Fractal analysis proved to be a reliable and objective method for the characterization of MCs

  7. Hyperpolarized 3helium magnetic resonance ventilation imaging of the lung in cystic fibrosis: comparison with high resolution CT and spirometry

    International Nuclear Information System (INIS)

    The purpose of this study was to compare hyperpolarized 3helium magnetic resonance imaging (3He MRI) of the lungs in adults with cystic fibrosis (CF) with high-resolution computed tomography (HRCT) and spirometry. Eight patients with stable CF prospectively underwent 3He MRI, HRCT, and spirometry within 1 week. Three-dimensional (3D) gradient-echo sequence was used during an 18-s breath-hold following inhalation of hyperpolarized 3He. Each lung was divided into six zones; 3He MRI was scored as percentage ventilation per lung zone. HRCT was scored using a modified Bhalla scoring system. Univariate (Spearman rank) and multivariate correlations were performed between 3He MRI, HRCT, and spirometry. Results are expressed as mean±SD (range). Spirometry is expressed as percent predicted. There were four men and four women, mean age=31.9±9 (20-46). Mean forced expiratory volume in 1 s (FEV)1=52%±29 (27-93). Mean 3He MRI score=74%±25 (55-100). Mean HRCT score=48.8±24 (13.5-83). The correlation between 3He MRI and HRCT was strong (R=±0.89, p3He MRI; 3He MRI correlated better with FEV1 and forced vital capacity (FVC) (R=0.86 and 0.93, p3He MRI correlates strongly with structural HRCT abnormalities and is a stronger correlate of spirometry than HRCT in CF. (orig.)

  8. Effect of observational holes and borders on lacunarity and fractality measurements in a galaxy catalogue

    CERN Document Server

    García-Farieta, Jorge E

    2016-01-01

    Cosmological observations reveal that the Universe contains a hierarchy of galaxy clustering with a transition to homogeneity on large scales according to the $\\Lambda$CDM model. Some observational estimates suggest that the Universe behaves as a multifractal object, where galactic clustering is based on generalisation of the dimension in metric spaces. From this point of view, we study the spatial distribution of points by simulating galaxies on large scales in the Universe with samples from the Sloan Digital Sky Survey (SDSS), including observational holes in the masks. We build homogeneous samples following the radial selection function using the "shuffle" method for a main sample of $3,273,548$ points limited to the redshift range $0.0020$ and percentages of holes near $40\\%$, $r_H$ is displaced on scales on the order of $120~Mpc/h$. Hole percentages between $10\\%$ and $30\\%$ show an $r_H$ of $70-90~Mpc/h$, and for percentages below $10\\%$, $r_H$ decreases to become equal to the $r_H$ value of the SDSS-BO...

  9. Free radical scavenger, edaravone, reduces the lesion size of lacunar infarction in human brain ischemic stroke

    Science.gov (United States)

    2011-01-01

    Background Although free radicals have been reported to play a role in the expansion of ischemic brain lesions, the effect of free radical scavengers is still under debate. In this study, the temporal profile of ischemic stroke lesion sizes was assessed for more than one year to evaluate the effect of edaravone which might reduce ischemic damage. Methods We sequentially enrolled acute ischemic stroke patients, who admitted between April 2003 and March 2004, into the edaravone(-) group (n = 83) and, who admitted between April 2004 and March 2005, into the edaravone(+) group (n = 93). Because, edaravone has been used as the standard treatment after April 2004 in our hospital. To assess the temporal profile of the stroke lesion size, the ratio of the area [T2-weighted magnetic resonance images (T2WI)/iffusion-weighted magnetic resonance images (DWI)] were calculated. Observations on T2WI were continued beyond one year, and observational times were classified into subacute (1-2 months after the onset), early chronic (3-6 month), late chronic (7-12 months) and old (≥13 months) stages. Neurological deficits were assessed by the National Institutes of Health Stroke Scale upon admission and at discharge and by the modified Rankin Scale at 1 year following stroke onset. Results Stroke lesion size was significantly attenuated in the edaravone(+) group compared with the edaravone(-) group in the period of early and late chronic observational stages. However, this reduction in lesion size was significant within a year and only for the small-vessel occlusion stroke patients treated with edaravone. Moreover, patients with small-vessel occlusion strokes that were treated with edaravone showed significant neurological improvement during their hospital stay, although there were no significant differences in outcome one year after the stroke. Conclusion Edaravone treatment reduced the volume of the infarct and improved neurological deficits during the subacute period, especially

  10. Correlation analysis between the carotid artery ather osclerosis severity of patients with lacunar infarct and the level of serum uric acid, high-sensitivity C-reactive protein

    Directory of Open Access Journals (Sweden)

    WANG Shu

    2013-01-01

    Full Text Available Background Nowadays, clinical practice shows that the number of patients with cerebral infarction increases year by year in young and middle-aged adults with unclear causes. This paper aims to investigate the correlation between the level of serum uric acid (UA, high-sensitivity C-reactive protein (hsCRP and the degree of carotid atherosclerosis by detecting the level of UA, hsCRP and carotid intima-media thickness (IMT in young and middle-aged patients with lacunar infarct. Methods By using Holland Philips HT-11 color Doppler ultrasonic diagnostic apparatus with linear type probe and 7.50MHz frequency, IMT of end-diastolic distal and bifurcation of arteria carotis communis and proximal internal carotid artery were measured respectively on 186 patients with definitely diagnosed lacunar infarct. As a result, average values were taken as the IMT values. IMT < 1.00 mm was regarded as negative result and 1.00 mm ≤IMT < 1.20 mm was thickening of carotid artery intima. Carotid artery plaque formation was regarded with echo structure existing in the lumen or abnormal blood flow deficits into the lumen, or local IMT ≥1.20 mm at vertical and horizontal scan. At the same time, the levels of UA and hsCRP were detected, and correlation analysis was made between them and IMT. Results The values of UA, hsCRP and IMT in the case group were higher than that in the control group (P = 0.000. The differences among the case subgroups including IMT thickening group, plaque formation group and IMT normal group were statistically significant (P < 0.01, for all. There was linear correlation between the levels of UA, hsCRP and IMT ( r = 0.923, P = 0.000; r = 0.955, P = 0.008. Conclusion UA and hsCRP involve in the formation of atherosclerosis plaque and play an important role in the first-onset lacunar infarct patients without hypertension and other risk factors.

  11. Chronic kidney disease, 24-h blood pressure and small vessel diseases are independently associated with cognitive impairment in lacunar infarct patients

    International Nuclear Information System (INIS)

    Although the relationships between chronic kidney disease (CKD) and cognitive impairment (CI) have been highlighted, the etiology of CI in CKD remains uncertain. Subjects comprised 224 consecutive patients with symptomatic lacunar infarction who underwent magnetic resonance imaging and ambulatory blood pressure monitoring (ABPM). Diurnal blood pressure (BP) patterns were categorized into three groups: dippers, non-dippers and risers. Lacunar infarcts (LIs), including both symptomatic and silent and diffuse white matter lesions (WMLs), were graded into three grades according to their degree. The results of kidney function were evaluated using estimated glomerular filtration rate (eGFR), categorized into three groups: stage 1, >60; stage 2, 30-60; and stage 3, -1 per 1.73 m2. There were 44 patients with CI. Confluent WMLs, including WML 2 and WML 3, were found in 36 patients (81.8%), and multiple lacunae including LI 2 and LI 3 were found in 30 patients (68.1%) with CI. Age >75 years (odds ratio (OR), 5.5; P-1 per 1.73 m2 (OR, 2.9; P-1 per 1.73 m2 (OR, 23.8; P75 years (OR, 4.1; P-1 per 1.73 m2 (OR, 3.7; P-1 per 1.73 m2 (OR, 8.7; P<0.05) were independently associated with WML grade 3. Extensive small vessel diseases, CKD and non-dipping status were independently associated with CI. CKD appears to mainly contribute to vascular CI, whereas possibilities of overlapping with other mechanisms such as degenerative CI cannot be excluded. Strict night time BP control and renoprotective treatment may be warranted to prevent CI. (author)

  12. 血管紧张素转换酶基因多态性与高血压病早期腔隙性脑梗死的关系%Relationships between angiotensin-converting enzyme gene polymorphism and lacunar infarction in early stage of essential hypertension

    Institute of Scientific and Technical Information of China (English)

    徐岩; 毛建华

    2003-01-01

    AIM:To investigate the relationships between angiotensin converting enzyme gene polymorphism and lacunar infarction in patients with essential hypertension.METHODS:Polymerase chain reaction(PCR) was used to determine the genotypes for an insertion/deletion polymorphism of 287 pb fragment of ACE gene in 50 healthy persons,50 patients with simple essential hypertension and 30 patients with essential hypertension and lacunar infarction.RESULTS:There was no significant difference of genotype and allele between healthy persons and patients with simple essential hypertension;but there was significant difference of D allele and DD genotype of ACE gene between esential hypertensive patients with lacunar infarction and patients with simple essential hypertension and healthy persons.CONCLUSION:There is a significant relation between ACE gene polymorphism and essential hypertensive patients with lacunar infarction.

  13. Correlation between lacunar infarction and glomeruar filtration rate in elderly patients%老年患者腔隙性脑梗死与肾小球滤过率的关系

    Institute of Scientific and Technical Information of China (English)

    李娜; 李辉; 胡新国; 程玲; 吴卫平; 管维平

    2012-01-01

    [Objective To study the correlation between lacunar infarction(LI) and glomeruar filtration rate(GFR) in elderly patients. Methods One hundred and twenty-seven MRI-confirmed male LI patients aged ≥80 years were divided into single lesion group(n = 35) and multiple lesion group(w = 92) according to the number of lesions. Following clinical data were collected,including 24 hdynamic blood pressure,age,BMI,and history of smoking,alcohol dinking,hypertension,diabetes mellitus,heart disease,and serum creatinine(SCr) and blood-lipid levels. GFR was estimated according to the Cockcroft-Gault equation. Correlation between GFR and LI level was analyzed by multiple logistic regression analysis. Results The SCr level was significantly higher while the GFR was significantly lower in multiple lesion group with its GFR <60 ml/(min ? 1. 73 m2) than in single lesion group(P<0. 05). Logistic regression analysis showed that the low GFR was closely correlated with the LI level, and the lower the GFR was, the higher the incidence of LI was (OR = 2. 14,P = 0. Oil). Conclusion Low GFR is an important risk factor for LI in elderly patients and can thus be used as a warning factor for LI.%目的 探讨老年(≥80岁)患者腔隙性脑梗死(lacunar infarction,LI)与肾小球滤过率(glomeruar filtration rate,GFR)的相关性.方法 选择经头颅MRI证实的老年男性LI患者127例,根据病灶数目分为单发组35例和多发组92例.采集患者的24 h动态血压、年龄、体重指数、吸烟、饮酒、血清肌酐、高血压、血脂、糖尿病、心脏病等临床资料,采用Cockcroft-Gault公式估算GFR.采用多因素logistic回归分析LI与GFR的相关性.结果 与单发组比较,多发组患者血清肌酐、GFR<60 ml/(min·1.73 m2)明显升高(P<0.01),GFR明显降低(P<0.05).logistic回归分析显示,GFR降低与LI的发生密切相关(P<0.05),GFR降低越严重,LI发生率越高(OR=2.14,P=0.011).结论 GFR降低可能为老年LI的重要危险因素,或可成为LI的预警因素.

  14. Hyperpolarized {sup 3}helium magnetic resonance ventilation imaging of the lung in cystic fibrosis: comparison with high resolution CT and spirometry

    Energy Technology Data Exchange (ETDEWEB)

    McMahon, Colm J.; Dodd, Jonathan D.; Skehan, Stephen J.; Masterson, James B. [St. Vincent' s University Hospital, Department of Radiology, Dublin (Ireland); Hill, Catherine; Woodhouse, Neil; Wild, Jim M.; Fichele, Stan [Royal Hallamshire Hospital, The Unit of Academic Radiology, University of Sheffield, Sheffield (United Kingdom); Gallagher, Charles G. [St. Vincent' s University Hospital, Department of National Referral Centre for Adult Cystic Fibrosis, Dublin (Ireland); Beek, Edwin J.R. van [Royal Hallamshire Hospital, The Unit of Academic Radiology, University of Sheffield, Sheffield (United Kingdom); University of Iowa, Department of Radiology, Carver College of Medicine, Iowa City, IA (United States)

    2006-11-15

    The purpose of this study was to compare hyperpolarized {sup 3}helium magnetic resonance imaging ({sup 3}He MRI) of the lungs in adults with cystic fibrosis (CF) with high-resolution computed tomography (HRCT) and spirometry. Eight patients with stable CF prospectively underwent {sup 3}He MRI, HRCT, and spirometry within 1 week. Three-dimensional (3D) gradient-echo sequence was used during an 18-s breath-hold following inhalation of hyperpolarized {sup 3}He. Each lung was divided into six zones; {sup 3}He MRI was scored as percentage ventilation per lung zone. HRCT was scored using a modified Bhalla scoring system. Univariate (Spearman rank) and multivariate correlations were performed between {sup 3}He MRI, HRCT, and spirometry. Results are expressed as mean{+-}SD (range). Spirometry is expressed as percent predicted. There were four men and four women, mean age=31.9{+-}9 (20-46). Mean forced expiratory volume in 1 s (FEV){sub 1}=52%{+-}29 (27-93). Mean {sup 3}He MRI score=74%{+-}25 (55-100). Mean HRCT score=48.8{+-}24 (13.5-83). The correlation between {sup 3}He MRI and HRCT was strong (R={+-}0.89, p<0.001). Bronchiectasis was the only independent predictor of {sup 3}He MRI; {sup 3}He MRI correlated better with FEV{sub 1} and forced vital capacity (FVC) (R=0.86 and 0.93, p<0.01, respectively) than HRCT (R={+-}0.72 and {+-}0.81, p<0.05, respectively). This study showed that {sup 3}He MRI correlates strongly with structural HRCT abnormalities and is a stronger correlate of spirometry than HRCT in CF. (orig.)

  15. Contribution to the determination of the double angular and energy differential neutron albedo. Application to the propagation in lacunar medium; Contribution a la determination de l'albedo doublement differentiel en angle et en energie des neutrons. Application a la propagation dans les milieux lacunaires

    Energy Technology Data Exchange (ETDEWEB)

    Litaize, O

    2000-07-01

    The goal of this thesis is to study the neutron propagation by reflection from lacunar medium interfaces. The most efficient method to calculate this type of propagation is to use the concept of albedo. Actual version of NARCISSE code uses a simple formulation of angular differential albedos and so, can only treat single reflections. Multiple reflections treatment needs the knowledge of neutron spectrum after reflection. This energetic information is contained in double angular and energy differential albedos. The first step of this study consists to generate these albedos for various materials. Several methods have been tested and the Monte Carlo method was retained. A new estimator has been developed and validated in the Mote Carlo transport code TRIPOLI-4. It computes, during the simulation of the neutron history, the angular and energy reflection probability at each collision site. The second step consists to generate an interpolation scheme and albedo libraries for various materials. A new version of NARCISSE was developed to use these libraries and the interpolation module. Spectrum and dose rates comparisons were made between codes to validate these albedos. The neutron propagation by multiple reflections can be studied now, by using this new version of Narcisse. (author)

  16. Iris Feature Extraction Algorithm Using Vertically Expanded Blanket Dimension and Lacunarity%基于毯子维和缺项的虹膜特征提取算法

    Institute of Scientific and Technical Information of China (English)

    刘凯; 周卫东; 王玉

    2011-01-01

    Iris feature extraction is important in iris recognition. An iris feature extraction algorithm is proposed by using combination of blanket dimension and lacunarity. Because Human iris texture is characterized by fractal geometry due to its rich self-similarity and abundant variation, vertically expanded blanket dimension is employed to represent iris texture variation and radial pattern at different resolution levels. Lacunarity is introduced to extract iris features that have different texture and fractal patterns but have same fractal dimension value. The combination of blanket dimension and lacunarity in iris feature extraction can embody the minute change of texture information comprehensively, and improve the capacity of iris classification. The experimental results on the CASIA-IrisV3-Interval iris database show that the combination of blanket dimension and lacunarity can extract iris textural features accurately and effectively, and high performance for iris recognition is achieved by using those features.%虹膜特征提取是虹膜识别的一个关键环节.文中提出一种毯子维和缺项相结合的虹膜特征提取算法.利用虹膜纹理的自相似和丰富的变化细节所具有的分形几何特性,采用纵向扩展毯子维表达不同分辨能力下虹膜纹理的变化及其辐射排列特点.通过引入缺项进一步提取不同纹理和分形表现却具有相同分形维数的虹膜特征.两者的结合能够更加全面地反映虹膜纹理的细腻变化.将归一化虹膜图像灰度值的毯子维及缺项用于虹膜分类,提高对虹膜的分类能力.针对CASIA-IrisV3-Interval数据库的仿真结果表明,纵向扩展毯子维结合缺项能够有效、快速提取虹膜的纹理信息,所获得的特征具有高的虹膜识别性能.

  17. Mechanisms of cognitive impairment in cerebral small vessel disease: multimodal MRI results from the St George's cognition and neuroimaging in stroke (SCANS study.

    Directory of Open Access Journals (Sweden)

    Andrew J Lawrence

    Full Text Available Cerebral small vessel disease (SVD is a common cause of vascular cognitive impairment. A number of disease features can be assessed on MRI including lacunar infarcts, T2 lesion volume, brain atrophy, and cerebral microbleeds. In addition, diffusion tensor imaging (DTI is sensitive to disruption of white matter ultrastructure, and recently it has been suggested that additional information on the pattern of damage may be obtained from axial diffusivity, a proposed marker of axonal damage, and radial diffusivity, an indicator of demyelination. We determined the contribution of these whole brain MRI markers to cognitive impairment in SVD. Consecutive patients with lacunar stroke and confluent leukoaraiosis were recruited into the ongoing SCANS study of cognitive impairment in SVD (n = 115, and underwent neuropsychological assessment and multimodal MRI. SVD subjects displayed poor performance on tests of executive function and processing speed. In the SVD group brain volume was lower, white matter hyperintensity volume higher and all diffusion characteristics differed significantly from control subjects (n = 50. On multi-predictor analysis independent predictors of executive function in SVD were lacunar infarct count and diffusivity of normal appearing white matter on DTI. Independent predictors of processing speed were lacunar infarct count and brain atrophy. Radial diffusivity was a stronger DTI predictor than axial diffusivity, suggesting ischaemic demyelination, seen neuropathologically in SVD, may be an important predictor of cognitive impairment in SVD. Our study provides information on the mechanism of cognitive impairment in SVD.

  18. Analysis of the intracranial lesions, cerebrovascular conditions and lacunar infarction in patients with migraine%偏头痛与脑血管发育异常、脑白质变性、脑腔梗关系分析

    Institute of Scientific and Technical Information of China (English)

    赵轶; 席刚明

    2014-01-01

    目的:观察偏头痛患者脑血管情况及颅内病变情况。方法:以住院偏头痛患者为研究对象、同一时期无偏头痛患者为对照,进行神经影像学比较。结果:58例偏头痛患者中,有脑腔梗病灶19例(32.76%),有脑白质变性17例(29.31%),有脑血管异常37例(63.79%)。61例对照组中有脑腔梗病灶9例(14.75%),有脑白质变性5例(8.20%),有脑血管异常13例(21.31%)。2组比较差异均有统计学意义(P<0.05)。结论:偏头痛与脑白质病变、脑腔梗有关,血管因素可能参与偏头痛的发作。%Objective:To obtain the intracranial lesions and cerebrovascular conditions in patients with migraine.Methods:Patient with migraine collected from the hospitalized were compared with patients with non-migraine in their neurimaging findings.Results:Among 58 patients with migraine, 19 had a or more lacunar infarctions;17 had white matter lesions and 37 had cerebrovascular abnormalities, while 61 patients with non-migraine had 9 lacunar infarctions, 5 white matter lesions and 13 cerebrovascular abnormalities. They were all signiifcantly different(P<0.05).Conclusion:Migraine was associated with the white matter lesions and lacunar infarction, while vascular factors may be involved in the migraine.

  19. 早期护理干预在腔隙性脑梗死认知功能康复的效果研究%Effect of early nursing intervention on cognitive function rehabilitation in patients with lacunar cerebral infarction

    Institute of Scientific and Technical Information of China (English)

    黄紫霞; 刘剑平; 李辉; 钟京梅; 徐柳

    2015-01-01

    目的 探讨早期护理干预对腔隙性脑梗死患者认知功能障碍康复的效果.方法 选择90例符合纳入标准的腔隙性脑梗死住院患者,使用中文版蒙特利尔认知评估(MoCA)量表进行认知功能障碍评分,将评分< 26分的患者随机分为实验组和对照组,对照组给予常规的认知康复护理,干预组予制定个体化认知功能康复护理以及手指操训练3个月,在15天、1月、2月、3月分别对两组进行认知功能康复测评.结果 实验组MoCA量表得分及视空间与执行功能、注意、抽象等认知功能评分在分组、时间、时间和分组的交互作用上差异均有统计学意义(P<0.05),记忆、定向两项在时间、时间和分组的交互作用上差异有统计学意义(P<0.05),分组与康复时间存在交互效应,随着时间的推进,两组干预效果差异有统计学意义.语言、命名方面两组差异无统计学意义(P>0.05).结论 早期护理干预对腔隙性脑梗死认知功能障碍的患者认知康复有良好的效果,值得推广.%Objective To explore the effect of early nursing intervention on cognitive function rehabilitation in patients with lacunar cerebral infarction.Methods 90 inpatients meeting the inclusion criteria of lacunar cerebral infarction were selected.Chinese version of Montreal cognitive assessment (MoCA) scale were used to evaluate cognitive dysfunction.The patients whose MoCA scores were below 26 were randomly divide into an experimental group and a control group.The control group received conventional cognitive rehabilitation nursing care,and the experimental group individualized rehabilitation nursing care and cognitive function finger exercise training for 3 months.Cognitive function rehabilitation evaluation was carried out in both group 15 days and 1,2,and 3 months from then.Results There were statistical differences in MoCA score and the scores of visual space,executive,attentiona,and abstract functions in

  20. 维生素B12与腔隙性脑梗塞后抑郁的关联研究%Association of Vitamin B12 with Depression after Lacunar Stroke

    Institute of Scientific and Technical Information of China (English)

    李中春; 呙登俊; 江霞

    2013-01-01

    OBJECTIVE To explore the association of serum vitamin B12 with depression after lacunar stroke.METHODS Between June 2009 and June 2012,829 patients with lacunar stroke,according to Hamilton depression scale score,were divided into two groups:group with depression and group without depression.The concentration of serum vitamin B 12 and the ratio of vitamin B12 deficiency were compared.The relationship between Hamilton depression scale score and the concentration of serum vitamin B 12 in the group with depression was analyzed by the curve-fitting method.RESULTS The group without depression contained 750 cases and the mean concentration of serum vitamin B12 of this group was (172.5±20.4)pmol·L-1.There were 212 cases in the group without depression which were considered as vitamin B 12 deficiency.The group with depression contained 79 cases and the mean concentration of serum vitamin B12 of this group was (139.1±18.2)pmol·L-1.There were 53 cases in the group with depression which were considered as vitamin B12 deficiency.There were significant differences in the concentration of serum vitamin B 12 and the ratio of vitamin B 12 deficiency(P<0.000 1).Inverse curve reflected the relationship between Hamilton depression scale score and the concentration of serum vitamin B 12 in the group with depression.CONCLUSION Depression after lacunar stroke is related to vitamin B12 deficiency.%目的 探讨血清维生素B12与腔隙性脑梗塞后抑郁之间关系.方法 2009年6月—2012年6月腔隙性脑梗塞患者共829例,使用汉密尔顿抑郁量表将患者分为两组:无抑郁组和抑郁组,比较两组间血清维生素B12浓度和维生素B12缺乏者的比例.在抑郁组内对汉密尔顿抑郁量表评分和血清维生素B12浓度进行曲线拟合.结果 无抑郁组患者750例,血清维生素B12平均浓度为(172.5±20.4)pmol·L-1,其中维生素B12缺乏者212例.抑郁组79例,血清维生素B12平均浓度为(139.1± 18.2)pmol·L-1,

  1. Correlation between cardio-ankle vaxcular index and lacunar infarction risk in elderly patients with hypertension%老年高血压患者心踝血管指数与腔隙性脑梗死风险相关性研究

    Institute of Scientific and Technical Information of China (English)

    王晓兵; 张薇; 田国祥; 陈初

    2013-01-01

    目的探讨老年高血压患者心踝血管指数(cardio-ankle vascuIar index,CAVI)与腔隙性脑梗死(LAC)相关性。方法纳入2010年1~2013年1月老年高血压患者193例,按CAVI值分为CAVI≥9.0组(n=110)和CAVI<9.0组(n=83),分析CAVI值与腔隙性脑梗死发生率的相关性。结果CAVI≥9.0组与CAVI<9.0组患者LAC发病率分别为17.3%和6.0%,差异有统计学意义(P<0.05)。Logistic回归分析显示,CAVI≥9.0组LAC的发生率是CAVI<9.0组的2.85倍(P<0.05)。结论 CAVI有助于评估老年高血压患者发生LAC风险。%Objective To discuss the correlation between cardio-ankle vascular index (CAVI) and lacunar infarction in elderly patients with hypertension. Methods The elderly patients with hypertension (n=193) were chosen from Jan. 2010 to Jan. 2013, and then divided into CAVI group 1 (CAVI≥9.0, n=110) and CAVI group 2 (CAVI<9.0, n=83). The correlation between CAVI and incidence of lacunar infarction was analyzed. Results The incidence of lacunar infarction was 17.3%in CAVI group 1 and 6.0%in CAVI group 2 (P<0.05). Logistic regression analysis showed that the incidence of lacunar infarction in CAVI group 1 was 2.85 times of that in CAVI group 2 (P<0.05). Conclusion CAVI can be used for reviewing the risk of lacunar infarction in elderly patients with hypertension.

  2. Carotid artery wall stiffness is increased in patients with small vessel disease: A case-control study

    OpenAIRE

    Salihović-Hajdarević Denisa; Pavlović Aleksandra M.; Smajlović Dževdet; Podgorac Ana; Jovanović Zagorka; Švabić-Međedović Tamara; Čovičković-Šternić Nadežda

    2016-01-01

    Introduction. Cerebral ischemic small-vessel disease (SVD), causing lacunar infarcts and white matter hyperintensities on brain magnetic resonance imaging (MRI), is a progressive disease associated with an increased risk of stroke, dementia and death. Increased arterial stiffness has been associated with ischemic stroke and cerebral SVD independently of common vascular risk factors. Objective. The aim of the study was to analyze arterial stiffness in our pa...

  3. 腔隙性脑梗死患者早期认知功能与脑血流动力学的改变%The changes of early cognitive function and cerebral hemodynamics in patients with lacunar cerebral infarction

    Institute of Scientific and Technical Information of China (English)

    李慧英; 郑晓风; 杨淑贞; 甄伟兰; 杨明宇; 梅飞来; 陈湘

    2015-01-01

    Objective Toinvestigatethechangesofcognitiveimpairmentandcerebralhemodynamics inpatientswithacutelacunarcerebralinfarctionwithin2weeksafteronset.Methods Nineteenpatients with lacunar cerebral infarction (a patient group)were consecutive enrolled in the study. Twenty-three sex-and age-matched inpatients without ischemic cerebrovascular disease or healthy volunteers of outpatient department over the same period were used as a control group. The cerebral hemodynamic features were evaluated with transcranial Doppler (TCD)"breath-holding test" and single photon emission computed tomography (SPECT)"resting + adenosine stress imaging". Simultaneously,the neuropsychological tests were performed,the Montreal cognitive assessment (MoCA)was performed including executive capacity, structural capacity,memory (including auditory memory,visual memory,and logic memory ),information processing speed,and visual-spatial ability. Results (1 )There were no significant differences in the years of education,hypertension,diabetes,hyperlipidemia,coronary heart disease,and smoking between the 2 groups (all P>0. 05). Compared with the control group,there were significant differences in the MoCA score,visual memory,executive function,structural capacity,and information processing speed of the patient group (all P<0. 05). (2)19 patients completed the SPECT resting + load test (12 in the control group and 7 in the patient group). There were significant differences in the uptake ratio (UR)in the right basal ganglia (8. 91[-2. 48 - 5. 87]and -6. 21 [-10. 39 - 5. 42 respectively])and left frontal lobe UR (11. 62 [2. 93-16. 87]and 1. 04 [-10. 17- 3. 82]respectively)between the patient group and the control group (P<0. 05). (3)26 patients completed the breath-holding test + head-up tilt table test (n=13 in each group]. The vascular motor reactivities were 13 ± 5 on the left and 21 ± 7 on the right, and the breath-holding indexes were 0. 66 ± 0. 26 on the left and 1. 0 ± 0. 4 on the right in the

  4. 68例腔隙性脑梗死MRI表现与血脂变化的相关性研究%The correlation of magnetic resonance imaging and lipid levels in 68 cases of lacunar infarction

    Institute of Scientific and Technical Information of China (English)

    田力; 赵一蓉; 刘翠芳

    2014-01-01

    目的:探讨腔隙性脑梗死(LI)的MRI表现与血脂变化的相关性。方法回顾性分析68例LI患者的MRI表现及其血脂水平,选取62例同期住院就诊的非心脑血管疾病患者为对照组,应用多元Logistic回归分析LI的M RI表现与血脂变化的相关关系。结果 L I患者M RI共检出299个腔隙性病灶,其中梗死病灶位于左侧大脑半球58个(19.40%),右侧大脑半球26个(8.70%),双侧基底节区73个(24.41%),丘脑27个(9.03%),侧脑室旁放射冠54个(18.06%),脑干39个(13.04%),小脑22个(7.36%)。LI患者的TC、TG、LDL-C和Ox-LDL水平显著增高(P<0.05),而HDL-C的水平明显低于对照组(P<0.05)。多元Logistic回归分析显示TC、TG、LDL-C、HDL-C和Ox-LDL对LI的相对危险度分别为1.56、1.27、1.39、1.46和1.44。结论 LI患者的M RI表现与血脂水平有一定程度的相关性,血脂水平升高可能是L I的重要危险因素。%Objective To explore relationship between magnetic resonance imaging (MRI) performance and lipid levels in pa-tients with lacunar infarction (LI) .Methods 68 patients with LI were retrospectively analyzed ,62 cases patients without heart ce-rebrovascular disease in the same period were choosen as control group ,the multivariate logistic regression was used to analyze the relationship between MRI performance ,the changed level of lipid .Results A total of 299 lacunar lesions were detected by MRI ,in which there were 58(19 .40% )in the left cerebral hemisphere ,26(8 .70% ) in the right hemisphere ,73(24 .41% ) in the bilateral basal ganglia ,27 (9 .03% ) in thalamus ,54 (18 .06% ) in the lateral ventricles corona radiata ,39 (13 .04% ) in brainstem ,and 22 (7 .36% ) in cerebellum .TC ,TG ,LDL-C and Ox-LDL levels in LI patients were significantly higher than the controls (P<0 .05) , while HDL-C levels were significantly lower than the controls (P<0

  5. CT 与 MRI 对腔隙性梗死的诊断价值分析%Analysis of compared CT with MRI in diagnosis value of lacunar infarction

    Institute of Scientific and Technical Information of China (English)

    严补生

    2015-01-01

    目的:比较C T与M RI对腔隙性梗死的诊断价值。方法选择腔隙性梗死患者40例为研究对象,均于入院3 h内行急诊螺旋CT及MRI检查。以临床诊断为准,观察CT 与MRI对腔隙性梗死病灶数量及部位诊断情况。比较CT 与MRI对发病<24 h、24~72 h、>72 h患者脑内病灶及径线<5 mm、5~10 mm和>10~15 mm病灶检出情况。结果(1)脑梗死病灶分布于额叶6例,顶叶6例,颞叶6例,枕叶4例,基底节区8例,丘脑3例,脑干3例,小脑4例。40例患者中,C T共显示21例患者存在脑梗死病灶,共显示病灶45处。M RI共显示38例患者存在脑梗死病灶,共显示病灶79处。M RI对脑梗死病灶检出率显著高于C T ,差异具有统计学意义( P<0.05)。(2)M RI对<24 h、24~72 h脑梗死病灶的检出率显著高于CT ,差异具有统计学意义(P<0.05)。两者在>72 h病灶的检出中,差异无统计学意义(P>0.05)。(3)其中MRI对径线<5 mm及5~10 mm腔隙性梗死病灶检出率显著高于CT ,差异具有统计学意义(P<0.05)。在病灶径线10~15 mm病灶的检出中,MRI及CT比较差异无统计学意义(P>0.05)。结论在腔隙性梗死的诊断中,MRI较CT更具有优势。%Objective To compare the value of CT and MRI in diagnosis of lacunar infarction.Methods 40 cases with la‐cunar cerebral infarction as the objects ,which were detected by spiral CT and MRI examination within 3 h admitted to our hos‐pital. Lesion number and site of cerebral lacunar infarction by CT and MRI were observed.The onset of cerebral infarction within 24 h ,between 24 h and 72 h ,more than 72 h;and diameter less than 5 mm ,between 5 mm and 10 mm ,between >10 and 15 mm detected by CT and MRI were compared.Results 6 cases of cerebral infarction lesions located in frontal lobe ,6 ca‐ses in parietal lobe ,6 cases in temporal lobe ,4 cases in occipital lobe ,8 cases in basal ganglia

  6. Relationship between Cerebral Microbleeds and White Matter Lesions and Lacunar ;Infarcts%脑微出血与脑白质病变及腔隙性梗死关系研究

    Institute of Scientific and Technical Information of China (English)

    高中宝; 赵杏丽; 王振福; 杨扬; 管锦群; 王婷; 吴卫平

    2015-01-01

    目的探讨脑微出血(cerebral microbleeds,CMBs)与脑白质病变(white matter lesions,WML)及腔隙性梗死(lacunar infarcts,LI)的关系。  方法连续纳入2010年2月至2012年2月解放军总医院南楼神经内科病房根据病史及头颅影像学检查确诊患有脑血管病或具有高血压、糖尿病、高脂血症等脑血管病危险因素者217例。采用G E公司1.5T磁共振成像行头颅常规序列及T2*血管加权成像(T2 star weighted angiography,SWAN)序列扫描。记录深部及皮层部位CMBs病灶数,按照Fazekas评分和Scheltens改良量表将脑室旁白质高信号(peri-ventricular hyperintensities,PVH)和深部白质高信号(deep white matter hyperintensities,DWMH)分别评分,根据病灶数量评估LI的严重程度分析CMBs与PVH、DWMH及LI的关系。  结果随着PVH和DWMH评分的升高,CMBs的检出率分别由41.8%(PVH=1)及40.8%(DWMH=1)升高至68.8%(PVH=3)及76.9%(DWMH=3);随着LI数量的增加,CMBs的检出率由46.3%升高至75%。深部CMBs与PVH及DWMH的严重程度有较强相关性(rs=0.345,P<0.001;rs=0.346,P<0.001),与LI亦显著相关(rs=0.281,P<0.001);而皮层CMBs与PVH及DWMH严重程度仅呈弱相关(rs=0.219,P=0.001;rs=0.189,P=0.005),与LI无显著相关性。  结论深部CMBs与脑室旁及深部脑白质病变、LI相关。%Objective To investigate the relationship between cerebral microbleeds(CMBs) and white matter lesions(WML) and lacunar infarcts(LI). Methods The identiifed population inculded 217 patients with cerebral vascular disease or related risk factors admitted to the Department of Geriatric Neurology of the PLA General Hospital between February, 2010 and February, 2012. Routine sequence and T2 star weighted angiography sequence of magnetic resonance imaging were performed with 1.5 Tesla machine maded by General Electric company. The number of CMBs in deep and

  7. 皮层下动脉硬化性脑病100例临床CT分析%CT and MRI T2WI, and FLAIR and DWI in diagnostic value of cerebral lacunar infarction and its prognosis analysis

    Institute of Scientific and Technical Information of China (English)

    罗青毅; 邹习忠; 冉强; 董志鹏

    2014-01-01

    目的:探讨皮层下动脉硬化性脑病颅脑ct诊断的意义和价值。方法结合我院临床诊断为皮层下动脉硬化性脑病, ct表现为侧脑室周围脑白质脱髓鞘改变的100例病例,按Goto分类法,将侧脑室前角周围脑白质脱髓鞘改变程度不同分为三型的标准,进行临床和影像综合分析。结果按Goto分类法Ⅰ型和Ⅱ型63例,临床表现轻,Ⅲ型37例,症状重,常偏瘫和言语不清,ct表现伴有脑萎缩(96例),腔隙性脑梗死(74例),伴大面积脑梗死(8例)、脑出血(7例)、脑积水和蛛网膜下腔积液(12例)。结论 ct检查对皮层下动脉硬化性脑病的诊断具有重要的价值,对于临床在预防、诊断和治疗皮层下动脉硬化性脑病方面具有重要意义。%Objectiveto explore the value of ct in diagnosis of subcortical arteriosclerotic encephalopathy (sae). Methods100 patients were deifnitely diagnosed as SAE by clinic. CT showed low density of surrounding bilateral ventricle. Demyelinating encephalopathy of frontal horn of bilateral ventricle were divided into three types according to the classiifcation of Goto.Results clinical presentations showed mild in typesⅠ andⅡ in 63 patients, severe symptoms were found in 37 patients, including hemiplegia, and barylalia. ct appeared cerebral atrophy in 96 patients; cerebral lacunar infarction in 74; diffuse cerebral infarction in 8; hemorrhage in 7; and hydrocephalus and hydrops of subarachnoid space in 12.Conclusion ct was very valuable on diagnosis and evaluation of subcortical arteriosclerotic encephalopathy.

  8. Numerical simulation of osteocyte cell in response to directional mechanical loadings and mechanotransduction analysis: Considering lacunar-canalicular interstitial fluid flow.

    Science.gov (United States)

    Joukar, Amin; Niroomand-Oscuii, Hanieh; Ghalichi, Farzan

    2016-09-01

    The osteocyte cell is a bone cell that also functions as a bone mechanosensor. In this work, a three-dimensional (3D) fluid-structure interaction (FSI) model of an osteocyte cell under different mechanical loading conditions was used to obtain a better understanding of osteocyte cell behavior under different physiological conditions. In the current study, both fluid and solid parts of osteocyte cell were considered in order to allow for more accurate results. Five different loading conditions have been applied to the osteocyte cell, and consequently the different interstitial fluid flow velocities and shear stresses have been investigated. Furthermore, using a mathematical model, the change in the stimulus function value with shear stress and NO enzyme was revealed. This work suggests that changes in osteocyte morphology and direction of loadings affect cell stimulation. It was found that cell is mostly stimulated and expanded in the direction experiencing the most shear stress. Finally, the amount of cell stimulation was shown quantitatively and there was strong dependency between stimulus function, shear stress, calcium, and NO concentration. PMID:27393805

  9. Clinical analysis of homocysteine, hypersensitive C-reactive protein and cognitive function in patients with early acute lacunar infarction%腔隙性脑梗死早期患者同型半胱氨酸、高敏C反应蛋白及认知功能的临床分析

    Institute of Scientific and Technical Information of China (English)

    王莹; 李慧英; 甄伟兰; 梅飞来

    2015-01-01

    目的:探讨腔隙性脑梗死早期患者认知功能的特点以及同型半胱氨酸(Hcy)、高敏C反应蛋白(hs-CRP)与认知功能障碍的相关性。方法选取2014年5月~2015年4月在北京航天总医院就诊的患者或体检者共50例,其中26例腔隙性脑梗死患者作为病例组,24例同期住院的无缺血性脑卒中患者或门诊健康志愿者作为对照组,测定两组Hcy和hs-CRP的含量,分析两项指标与腔隙性脑梗死的关系;对受试者进行全面的神经心理学测试,包括蒙特利尔认知评估量表(MoCA)、视空间能力、记忆力(包括听觉记忆、视觉记忆和逻辑记忆)、执行能力、结构能力、信息处理速度检查等,比较两组测试结果有无差别,分析影响腔隙性脑梗死的相关因素,并分析血浆Hcy和hs-CRP水平与受试者MoCA得分的相关性。结果病例组血浆Hcy和hs-CRP水平较对照组显著增高,差异有统计学意义(P<0.05);病例组MoCA评分视觉记忆、听觉记忆(即刻记忆、长延迟回忆)、执行能力、结构能力(积木测试、画钟测试)、视空间能力较对照组显著降低,差异有统计学意义(P<0.05)。影响腔隙性脑梗死的相关因素包括高脂血症、冠心病、高hs-CRP(P<0.05)。血浆Hcy和hs-CRP水平与受试者MoCA得分呈负相关,差异有统计学意义(r=-0.327、-0.117,P=0.021、0.397)。结论血浆Hcy和hs-CRP增高可能是腔隙性脑梗死的危险因素;腔隙性脑梗死患者早期已经存在不同程度的认知功能障碍,且与高Hcy和高hs-CRP存在一定的相关性。%Objective To investigate the features of cognitive function of patients with early acute lacunar infarction and the correlation of homocysteine (Hcy), high-sensitivity C-reactive protein (hs-CRP) and cognitive dysfunction. Methods Fifty cases of patients or physical examinees in the Department of Neurology of Beijing Aerospace General Hospital from May 2014 to April 2015 were

  10. The cognitive changes in patients with lacunar infarction after antery-intervention therapy%腔隙性脑梗死患者介入治疗术后认知功能变化

    Institute of Scientific and Technical Information of China (English)

    赵秀芹; 赵冰; 夏章勇; 杨华; 张凤娥; 郭存举; 曲怀谦

    2012-01-01

    Objective To explore the characteristics of the cognitive changes in patients with lacunar infarction(LI) after carotid artery stenting(CAS).Methods Neuropsychological tests were conducted in 43 patients with LI and carotid stenosis before and 1 month,6 months,12 months after CAS and the scores were compared with those of 41 healthy cases.Results Compared with control group,MMSE scores ( 26.33 ± 1.94),memory and executive function in therapy group lowered obviously.There was statistical difference (P< 0.05 or P< 0.01 ).Compared with before CAS,MMSE scores of 1 month (27.17±2.15),6 months (27.17 ±2.15),12 months (28.15±1.98) after CAS,memory and executive function in therapy group were all better obviously.There was statistical difference (P<0.05 or P<0.01).Conclusion In acute stage of patients with LI (with in 1 week),most cognitive impairment was severe. Most cognition disorders was improved to normal level 12 months after CAS.The mechanism may be associated with the improvement of chronic cerebral insufficiency.%目的 探讨腔隙性脑梗死患者介入治疗术后认知的功能变化特点.方法 43例伴颈动脉狭窄的腔隙性脑梗死患者分别于术前及术后1个月、6个月、12个月进行神经心理学测验,并与41例正常人比较.结果 与对照组比较,治疗组患者术前简易智能状态检查量表( MMSE)评分[(26.33±1.94)分]、记忆力、执行能力均降低,差异有统计学意义(P<0.05或P<0.01).与术前比较,治疗组患者MMSE评分术后1月[(27.17 ±2.15)分]、术后6月[(27.78±2.12)分]、术后12月[(28.15±1.98)分],及记忆力、执行能力大都明显改善,差异有统计学意义(P<0.05或P<0.01).结论 腔隙性脑梗死患者急性期(发病1周内)大部分认知功能损害较重,介入治疗12月后大都恢复正常,其机制可能与慢性脑供血不足的改善有关.

  11. 腔隙性梗死和脑白质病变患者的认知损害%Cognitive impairment in patient with lacunar infarct and white matter lesion

    Institute of Scientific and Technical Information of China (English)

    张永红; 王海峰; 王新; 张莉; 邢成名

    2014-01-01

    目的 探讨腔隙性梗死(lacunar infarct,LI)和脑白质病变(white matter lesion,WML)患者认知损害的特征及其危险因素.方法 纳入年龄65 ~ 75岁的LI和WML住院患者,收集其人口统计学和临床资料.LI和WML通过MRI确诊.采用蒙特利尔认知评估量表(Montreal Cognitive Assessment,MoCA)评价认知功能.采用抑郁自评量表和汉密尔顿焦虑量表排除抑郁和焦虑患者.根据MoCA总分将患者分为认知损害组和认知功能正常组,比较两组人口统计学和临床资料.采用多变量logistic回归分析确定认知损害的独立危险因素.对LI和WML的认知损害特征进行比较.结果 共纳入130例LI或WML患者.其中,92例存在认知损害,38例认知功能正常;85例存在LI,45例存在WML;男性53例,女性77例.单变量分析显示,认知损害组受教育年限[(7.54±4.65)年对(11.29±3.17)年;t=4.286,P=0.001]显著性低于认知正常组,而高血压(54.6%对16.2%;x2=4.477,P=0.018)、高脂血症(53.1%对16.2%;x2=5.263,P =0.044)、糖尿病(46.9%对10.8%;x2=3.827,P=0.017)以及LI(43.8%对21.5%;x2=3.928,P=0.015)和WML(26.9%对7.7%;x2=4.072,P=0.009)的构成比显著性高于认知正常组.多变量logistic回归分析显示,受教育年限[优势比(odds ratio,OR)1.305,95%可信区间(confidence interval,CI)1.104 ~7.975;P=0.001]、糖尿病(OR 1.328,95% CI 1.292~3.422;P=0.015)、高血压(OR1.978,95%CI1.034~5.443;P=0.028)、LI(OR 1.224,95% CI1.004 ~2.007;P=0.013)和WML(OR 1.489,95% CI 1.202~3.778;P=0.010)是认知损害的独立危险因素.WML组MoCA总分[(21.61±5.33)分对(19.19±7.07)分;t=1.841,P=0.038]以及立方体复制[(0.43±0.50)分对(0.31 ±0.47)分;t=1.104,P=0.010]、画钟实验[(2.53 ±0.89)分对(2.04±1.22)分;t=2.229,P=0.008]、字母辨别[(0.85±0.36)分对(0.62±0.50)分;t=2.585 P=0.000]和100连续减7[(2.62±0.79)分对(2.19±1.17)分;=2.113;P=0.001]得分均显著性低于LI组.结论 LI和WML患者均常伴

  12. Clinical study of cerebral infarction in hemodialysis patients

    International Nuclear Information System (INIS)

    Stroke is one of the leading causes of death in patients undergoing chronic dialysis. However, few clinical studies have so far examined stroke, especially brain infarction, under such conditions. We retrospectively evaluated the clinical features and risk factors for brain infarction in 33 patients undergoing hemodialysis (hemodialysis, 29 patients; continuous ambulatory peritoneal dialysis, 4 patients; male:female ratio, 25:8) between May 2003 and August 2006. The mean age was 68.5±10.9 (mean±standard deviation (SD)) years. The basal renal diseases were chronic glomerulonephritis (n=16), diabetes mellitus (n=10) and other diseases (n=7). The mean duration of maintenance dialysis before the onset of stroke was 5.6±5.2 years. All 33 patients developed brain infarction, including the atherothrombotic (n=13), lacunar (n=9) and cardioembolic (n=11) types. The complications included a high frequency of hypertension (79%) in all groups, diabetes mellitus (36%) and atrial fibrillation (21%). Four of the patients, 2 with lacunar and 2 with atherothrombotic infarction, developed brain infarction within 3 hours after hemodialysis. Hemodynamic changes might have caused the infarction in these patients. The proportion of patients with a modified Rankin Scale grade of 4-6 at discharge was 42%, and the mortality rate was high (15%). The prognosis of brain infarction was poorer in patients with hemodialysis than in those without. (author)

  13. Asymptomatic ischemic cerebral lesions; MRI study on a high risk group

    Energy Technology Data Exchange (ETDEWEB)

    Udaka, Fukashi; Fushimi, Hisako; Kishino, Bunichiro; Kameyama, Masakuni (Sumitomo Hospital, Osaka (Japan))

    1988-11-01

    For the purpose of studying the incidence, pathomorphology and etiology of asymptomatic ischemic cerebral lesions, we carried out a brain MRI study on 65 patients with diabetes mellitus accompanied with hypertension who are thought to belong to a high risk group of ischemic cerebrovascular diseases. Excluding the abnormality of tendon reflex due to diabetic neuropathy, sixty percent of the total patients had some mild neurological signs and symptoms, most of them was discrepancy in tendon reflex. The percentage of the patients in whom MRI disclosed some abnormalities was as high as 70%, they were lacunar stroke, multiple lacunar state, cortical infarct, and patchy high signal lesions visible only in the T{sub 2} weighted image. Lacunes or these patchy high signal lesions (considered to be the dilatation of the perivascular space or true lacunes) tended to be found along the border zone or the terminal zone. These results indicate that asymptomatic patients in whom MRI discloses the abnormalities should be considered as candidates for the future onset of multi-infarct. (author).

  14. 载荷强度对受载胫骨中骨陷窝-骨小管系统内溶质输运速率影响%The influence from load strength on solute transport rate of lacunar-canalicular system in loaded tibia

    Institute of Scientific and Technical Information of China (English)

    王玉琨; 樊黎霞

    2015-01-01

    目的 利用有限元法研究载荷强度对受载胫骨中骨陷窝-骨小管系统(lacunar-canalicular system,LCS)内溶质输运速率的影响.方法 基于成年鼠胫骨的micro-CT扫描图像,利用Mimics、Hypermesh、FEBio等软件建立其胫骨有限元模型,且视为均质的两相-溶质材料.通过设置3组不同扩散率(3、15、30μm2/s)的溶质和载荷强度(0.2、2.0、5.0 N),得到输运速率和溶质扩散率以及载荷强度之间的关系.对比光脱色荧光恢复(fluorescence recovery after photobleaching,FRAP)实验数据与有限元法得到的结果,分析载荷刺激对输运增强率的影响.结果 输运速率均随着扩散率和载荷强度的增大而增大.通过与FRAP实验的数据进行比对发现,有限元法得到的结果基本符合溶质运移规律.结论 研究结果可为研究皮质骨深层区域的力响应以及流动性提供一定基础,也为进一步揭示骨再生机制提供借鉴.

  15. Effect of early nursing intervention on cognitive and compliance of cognitive function rehabilitation in patients with lacunar infarction%早期护理干预对腔隙性脑梗死患者认知功能康复认知及依从性的影响

    Institute of Scientific and Technical Information of China (English)

    黄紫霞; 刘剑平

    2013-01-01

    目的 探讨早期护理干预对腔隙性脑梗死患者认知功能障碍康复认知及依从性的影响.方法 选择61例初次发病的腔隙性脑梗死住院患者,使用中文版蒙特利尔认知评估(MoCA)量表进行认知功能障碍评分,将评分<26分的患者随机分为实验组和对照组,对照组(31例)给予常规的认知康复护理,实验组(30例)在常规的康复护理基础上实施早期护理干预3个月,即根据患者情况制定个体化认知功能康复训练以及手指操训练,在干预前、后两组进行认知康复治疗的认知情况比较,在干预1,2,3个月后对两组进行认知功能康复治疗的依从性进行调查.结果 护理干预前,两组的认知功能康复认知状况分别得分(4.8±0.68)和(4.8±0.54),差异无统计学意义(P>0.05),干预后2周实验组和对照组的认知功能康复认知状况得分分别为(15.7±2.65),(11.5 ±1.87)分,差异有统计学意义(t=7.088,P<0.01);经护理干预3个月后,实验组的认知功能康复治疗的依从性在1,2,3个月均显著高于对照组,差异均有统计学意义(P<0.05).结论 对腔隙性脑梗死认知功能障碍的患者进行早期护理干预可以显著提高认知功能康复治疗的依从性.%Objective To investigate the effect of early nursing intervention on cognitive and compliance of cognitive function rehabilitation in patients with lacunar infarction.Methods 61 patients with lacunar infarction were chosen and Montreal cognitive assessment (MoCA) was used to evaluate their cognitive dysfunction.Those who scored less than 26 were randomly divided into the experimental group and the control group.The control group was given conventional cognitive rehabilitation nursing,while the experimental group was given early nursing intervention for 3 months in addition,which included developing individual rehabilitation exercise and finger operation training according to patients' conditions.Two weeks after intervention

  16. Correlation analysis between the carotid artery atherosclerosis severity of patientswith lacunar infarct and the level of serum uric acid, high - sensitivity C - reactiveprotein%血清尿酸、超敏C-反应蛋白与腔隙性脑梗死患者颈动脉粥样硬化程度的相关分析

    Institute of Scientific and Technical Information of China (English)

    王姝

    2013-01-01

    Background Nowadays, clinical practice shows that the number of patients with cerebral infarction increases year by year in young and middle-aged adults with unclear causes. This paper aims to investigate the correlation between the level of serum uric acid (UA), high - sensitivity C-reactive protein (hsCRP) and the degree of carotid atherosclerosis by detecting the level of UA, hsCRP and carotid intima-media thickness (IMT) in young and middle-aged patients with lacunar infarct. Methods By using Holland Philips HT-11 color Doppler ultrasonic diagnostic apparatus with linear type probe and 7.50 MHz frequency, IMT of end - diastolic distal and bifurcation of arteria carotis communis and proximal internal carotid artery were measured respectively on 186 patients with definitely diagnosed lacunar infarct. As a result, average values were taken as the IMT values. IMT < 1.00 mm was regarded as negative result and 1.00 mm ≤ IMT < 1.20 mm was thickening of carotid artery intima. Carotid artery plaque formation was regarded with echo structure existing in the lumen or abnormal blood flow deficits into the lumen, or local IMT ≥ 1.20 mm at vertical and horizontal scan. At the same time, the levels of UA and hsCRP were detected, and correlation analysis was made between them and IMT. Results The values of UA, hsCRP and IMT in the case group were higher than that in the control group (P = 0.000). The differences among the case subgroups including IMT thickening group, plaque formation group and IMT normal group were statistically significant (P<0.01, for all). There was linear correlation between the levels of UA, hsCRP and IMT (r = 0.923, P = 0.000; r = 0.955, P = 0.008). Conclusion UA and hsCRP involve in the formation of atherosclerosis plaque and play an important role in the first - onset lacunar infarct patients without hypertension and other risk factors.%研究背景 中青年脑梗死患者呈逐年增加趋势,病因尚不明确.通过对中青年腔隙性脑梗

  17. Hyperpolarized {sup 3}He magnetic resonance imaging: Preliminary evaluation of phenotyping potential in chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Mathew, Lindsay, E-mail: lmathew@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Department of Medical Biophysics, University of Western Ontario, London (Canada); Kirby, Miranda, E-mail: mkirby@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Department of Medical Biophysics, University of Western Ontario, London (Canada); Etemad-Rezai, Roya, E-mail: Roya.EtemadRezai@lhsc.on.ca [Department of Medical Imaging, University of Western Ontario (Canada); Wheatley, Andrew, E-mail: awheat@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); McCormack, David G., E-mail: David.McCormack@lhsc.on.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Division of Respirology, Department of Medicine, University of Western Ontario, London (Canada); Lawson Health Research Institute, London (Canada); Parraga, Grace, E-mail: gep@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Department of Medical Biophysics, University of Western Ontario, London (Canada); Department of Medical Imaging, University of Western Ontario (Canada); Lawson Health Research Institute, London (Canada)

    2011-07-15

    Rationale and objectives: Emphysema and small airway obstruction are the pathological hallmarks of chronic obstructive pulmonary disease (COPD). The aim of this pilot study in a small group of chronic obstructive pulmonary disease (COPD) patients was to quantify hyperpolarized helium-3 ({sup 3}He) magnetic resonance imaging (MRI) functional and structural measurements and to explore the potential role for {sup 3}He MRI in detecting the lung structural and functional COPD phenotypes. Materials and methods: We evaluated 20 ex-smokers with stage I (n = 1), stage II (n = 9) and stage III COPD (n = 10). All subjects underwent same-day plethysmography, spirometry, {sup 1}H MRI and hyperpolarized {sup 3}He MRI at 3.0 T. {sup 3}He ventilation defect percent (VDP) was generated from {sup 3}He static ventilation images and {sup 1}H thoracic images and the {sup 3}He apparent diffusion coefficient (ADC) was derived from diffusion-weighted MRI. Results: Based on the relative contribution of normalized ADC and VDP, there was evidence of a predominant {sup 3}He MRI measurement in seven patients (n = 3 mainly ventilation defects or VDP dominant (VD), n = 4 mainly increased ADC or ADC dominant (AD)). Analysis of variance (ANOVA) showed significantly lower ADC for subjects with predominantly elevated VDP (p = 0.02 compared to subjects with predominantly elevated ADC; p = 0.008 compared to mixed group) and significantly decreased VDP for subjects with predominantly elevated ADC (p = 0.003, compared to mixed group). Conclusion: In this small pilot study, a preliminary analysis shows the potential for {sup 3}He MRI to categorize or phenotype COPD ex-smokers, providing good evidence of feasibility for larger prospective studies.

  18. Hyperpolarized 3He magnetic resonance imaging: Preliminary evaluation of phenotyping potential in chronic obstructive pulmonary disease

    International Nuclear Information System (INIS)

    Rationale and objectives: Emphysema and small airway obstruction are the pathological hallmarks of chronic obstructive pulmonary disease (COPD). The aim of this pilot study in a small group of chronic obstructive pulmonary disease (COPD) patients was to quantify hyperpolarized helium-3 (3He) magnetic resonance imaging (MRI) functional and structural measurements and to explore the potential role for 3He MRI in detecting the lung structural and functional COPD phenotypes. Materials and methods: We evaluated 20 ex-smokers with stage I (n = 1), stage II (n = 9) and stage III COPD (n = 10). All subjects underwent same-day plethysmography, spirometry, 1H MRI and hyperpolarized 3He MRI at 3.0 T. 3He ventilation defect percent (VDP) was generated from 3He static ventilation images and 1H thoracic images and the 3He apparent diffusion coefficient (ADC) was derived from diffusion-weighted MRI. Results: Based on the relative contribution of normalized ADC and VDP, there was evidence of a predominant 3He MRI measurement in seven patients (n = 3 mainly ventilation defects or VDP dominant (VD), n = 4 mainly increased ADC or ADC dominant (AD)). Analysis of variance (ANOVA) showed significantly lower ADC for subjects with predominantly elevated VDP (p = 0.02 compared to subjects with predominantly elevated ADC; p = 0.008 compared to mixed group) and significantly decreased VDP for subjects with predominantly elevated ADC (p = 0.003, compared to mixed group). Conclusion: In this small pilot study, a preliminary analysis shows the potential for 3He MRI to categorize or phenotype COPD ex-smokers, providing good evidence of feasibility for larger prospective studies.

  19. Lacunar thalamic stroke with pure cerebellar and proprioceptive deficits.

    OpenAIRE

    Gutrecht, J A; Zamani, A A; D N Pandya

    1992-01-01

    Case reports of two patients with cerebellar ataxia and proprioceptive sensory loss are presented. MRI of the brain revealed lesions of the ventroposterior part of the thalamus. These patients illustrate clinically the anatomical independence of cerebellar and sensory pathways in the thalamus. We suggest that the ataxic deficit is caused by interruption of cerebellar outflow pathways in the thalamus and not secondary to sensory deafferentation.

  20. Application Value of Montreal Cognitive Assessment in Lacunar Infarction Patients with Cognitive Impairment%蒙特利尔认知评估量表对腔隙性脑梗死患者认知功能障碍的评估价值研究

    Institute of Scientific and Technical Information of China (English)

    肖桂荣; 孙新芳; 章燕幸; 赵宏军; 桂小红

    2012-01-01

    目的 探讨蒙特利尔认知评估量表(Montreal Cognitive Assessment,MoCA)(中文版)在腔隙性脑梗死患者认知功能障碍评估中的应用价值.方法 首先采用中文版简易智能状态量表(Mini-Mental State Examination,MMSE)对确诊为腔隙性脑梗死患者进行筛选,然后对经过受教育程度矫正后MMSE得分正常的患者采用中文版MoCA进行评分,使用26分作为分界值.MoCA<26分者纳入腔隙性脑梗死认知功能障碍组(LI-CI组),MoCA≥26分者纳入腔隙性脑梗死认知功能正常组(LI-NC组).比较两组患者MoCA评分、MMSE评分及MoCA各个认知领域得分情况.结果 MMSE得分正常的患者有53%(50/94)MoCA评分<26分,这些患者的认知功能与MoCA评分≥26分的患者比较,差异有统计学意义﹙P<0.01﹚;LI-CI组在视空间功能与执行功能、命名、抽象、延迟回忆认知领域方面得分低于LI-NC组,差异均有统计学意义(P<0.05).结论 MoCA在筛查腔隙性脑梗死患者认知障碍方面可能比MMSE更为敏感,对于MMSE评分正常MoCA评测异常的患者认知损害主要表现在视空间与执行功能、命名、延迟记忆以及抽象等方面.%Objective To analyze the application value of Montreal Cognitive Assessment (MoCA) ( Chinese version ) in detecting cognitive impairment in patients with lacunar infarction (LI). Methods The patients confirmed with LI were first screened by Mini - Mental State Examination ( MMSE) , and patients having normal MMSE score were further assessed by MoCA after education adjustment (26 as the cut - off score). The patients with MoCA score less than 26 were selected as cognitive im-paired LI - CI group and the patients with more than 26 were selected as normal control LI - NC group. MoCA score, MMSE score and scores of each cognitive field of MoCA were compared between the two groups. Results 53% (50/94) Li patients with nor-mal MMSE score had MoCA socre < 26, and these patients' cognitive function

  1. Quantitative imaging of alveolar recruitment with hyperpolarized gas MRI during mechanical ventilation

    OpenAIRE

    Cereda, Maurizio; Emami, Kiarash; Kadlecek, Stephen; Xin, Yi; Mongkolwisetwara, Puttisarn; Profka, Harrilla; Barulic, Amy; Pickup, Stephen; Månsson, Sven; Wollmer, Per; Ishii, Masaru; Deutschman, Clifford S.; Rizi, Rahim R.

    2010-01-01

    The aim of this study was to assess the utility of 3He MRI to noninvasively probe the effects of positive end-expiratory pressure (PEEP) maneuvers on alveolar recruitment and atelectasis buildup in mechanically ventilated animals. Sprague-Dawley rats (n = 13) were anesthetized, intubated, and ventilated in the supine position (4He-to-O2 ratio: 4:1; tidal volume: 10 ml/kg, 60 breaths/min, and inspiration-to-expiration ratio: 1:2). Recruitment maneuvers consisted of either a stepwise increase o...

  2. Pattern of hospitalized-stroke patients in ASEAN countries an ASNA stroke epidemiological study

    Directory of Open Access Journals (Sweden)

    Jusuf Misbach

    2001-03-01

    Full Text Available To better understanding the demographic characteristics, admission time, clinical pattern, risk factors, stroke type, length of stay, and discharge outcome of hospitalized acute stroke patients in ASEAN member countries, ASEAN   Neurological Association (ASNA formed a Standing Commiltee for Stroke in 1996 and this is the first ASNA Stroke Epidemiological Study using the same stroke protocol. This prospective hospital based study was conducted in seven ASEAN countries (Brunei, Indonesia, Malaysia, Philippines, Singapore, Thailand, and Vietnam by participating neurologists from October 1996 to March 1997. Of the 3723 consecutive hospitalized stroke patients (2030 males and 1660 females from 44 participating hospitals in this study ie Brunei (n=53, Indonesia (n=2065, Malaysia (n=300,Philippines (n=545,Singapore (n=232, Thailand (n=244 and Vietnam (n=284, the mean age was 59.0 ± 13,8 years 16% of patients were younger than 45 years and 37% of patients were older than 65 years. There were no significant differences in age at onset among stroke subjects except in Vietnam (younger and Singapore (older. The sex distribution showed a slight higher prevalence of women in Singapore and in the age group > 64 years. The mean adrnission time was 41.5 ± 87.0 hours, 19% of patients were admitted within 3 hours, 29% within 6 hours and 66% more than 6 hours (delayed admission especially in Malaysia and Singapore (80% and 77% respectively. Motor disability was the most prevalent clinical feature in all countries and carotid bruit was the rarest (1%. Hypertension was the most common risk factor (68% in all countries, followed by TIA (35%, smoking, diabetes mellitus, ischnemic heart disease and hypercholesterolemia. CT scan was performed on 76% of subjects. The diagnostic classification was non lacunar anterior circulation (32%, lacunar infarction (14%, hemorrhagic stroke (26%, SAH (4%. Mean length of stay was 11.4 ± 11.8 days. Most of the patients

  3. [Descriptive study of cerebrovascular accidents in Douala, Cameroon].

    Science.gov (United States)

    Chiasseu, Mbeumi M T; Mbahe, S

    2011-10-01

    A cerebrovascular accident or stroke is a sudden-onset cerebral deficit of vascular origin lasting more than 24 hours. These events represent the second leading cause of death in the world and take a particularly heavy toll in third world countries. The purpose of this study was to describe cerebrovascular lesions (type, location, size) as well as patient age and gender in Cameroon. Brain CT-scan and MRI findings from 50 stroke patients admitted to two health centers in Douala were reviewed. Data showed that 74% of patients were over 50 years of age, the 51-60 year group being the most affected. Patients were male in 64% of cases. Ischemic stroke accounted for 60% of cases versus 40% for hemorrhagic stroke. The most affected sites were the sylvian territory site in ischemic stroke and the temporal lobe in hemorrhagic stroke, acconting for 43.3% and 35% of cases respectively. The median size of ischemic and hemorrhagic lesions were 2.81 cm3, and 26.98 cm3 respectively. Hemorrhagic stroke and lacunar infarcts were more common in this sample. Discrepancies between results at the two hospitals may be due to the use of different imaging techniques. Indeed, MRI is known to be more sensitive than CT-scan for acute detection of stroke lesions. PMID:22235625

  4. An exploratory intervention study suggests clinical benefits of training in chronic stroke to be paralleled by changes in brain activity using repeated fMRI

    Directory of Open Access Journals (Sweden)

    Landsmann B

    2016-01-01

    Full Text Available Barbara Landsmann,1,2 Daniela Pinter,2 Eva Pirker,1,2 Gerald Pichler,3 Walter Schippinger,3 Elisabeth M Weiss,1 Gabriel Mathie,2 Thomas Gattringer,2 Franz Fazekas,2 Christian Enzinger2,4 1Institute of Psychology, University of Graz, Graz, Austria; 2Department of Neurology, Medical University of Graz, Graz, Austria; 3Albert Schweitzer Clinic Graz, Graz, Austria; 4Division of Neuroradiology, Department of Radiology, Medical University of Graz, Graz, Austria Purpose: Previous studies demonstrated changes in sensorimotor network activation over time after stroke that have been interpreted as partly compensatory. Locomotor and balance trainings may improve both mobility and cognition even in chronic stroke and thereby impact on cerebral activation patterns. We here aimed at testing these assumptions in an exploratory study to inform subsequent larger intervention studies. Patients and methods: Eight patients (73.3±4.4 years with a chronic lacunar stroke (mean interval 3.7 years after the acute event with a range from 2 to 4 years and residual leg paresis leading to gait disturbance received a guided 5-week training focusing on mobility, endurance, and coordination. Before and afterward, they underwent clinical, neuropsychological, and gait assessments and brain MRI at 3 T including a functional ankle movement paradigm. Sixteen healthy controls (HCs; 68.8±5.4 years followed the same protocol without intervention. Results: After training, patients had improved in mobility, memory, and delayed recall of memory. While cerebral activations in HC remained completely unaltered, patients showed increased activations in the right precentral gyrus, the right and left superior frontal gyri, and the right frontal lobe, with bipedal ankle movements after training. Conclusion: In this exploratory study of chronic stroke, we found not only significant effects of physical training on mobility but also distinct aspects of cognition already with a small number of

  5. In-hospital cerebrovascular complications following orthotopic liver transplantation: A retrospective study

    Directory of Open Access Journals (Sweden)

    Liang Zhijian

    2008-12-01

    Full Text Available Abstract Background Cerebrovascular complications are severe events following orthotopic liver transplantation (OLT. This study aimed to observe the clinical and neuroimaging features and possible risk factors of in-hospital cerebrovascular complications in the patients who underwent OLT. Patients and methods We retrospectively reviewed 337 consecutive patients who underwent 358 OLTs. Cerebrovascular complications were determined by clinical and neuroimaging manifestations, and the possible risk factors were analyzed in the patients with intracranial hemorrhage. Results Ten of 337 (3.0% patients developed in-hospital cerebrovascular complications (8 cases experienced intracranial hemorrhage and 2 cases had cerebral infarction, and 6 of them died. The clinical presentations were similar to common stroke, but with rapid deterioration at early stage. The hematomas on brain CT scan were massive, irregular, multifocal and diffuse, and most of them were located at brain lobes and might enlarge or rebleed. Infarcts presented lacunar and multifocal lesions in basal gangliar but with possible hemorrhagic transformation. The patients with intracranial hemorrhage had older age and a more frequency of systemic infection than non-intracranial hemorrhage patients. (P = 0.011 and 0.029, respectively. Conclusion Posttransplant cerebrovascular complications have severe impact on outcome of the patients who received OLT. Older age and systemic infection may be the possible risk factors of in-hospital intracranial hemorrhage following OLT.

  6. Risk and Determinants of Dementia in Patients with Mild Cognitive Impairment and Brain Subcortical Vascular Changes: A Study of Clinical, Neuroimaging, and Biological Markers—The VMCI-Tuscany Study: Rationale, Design, and Methodology

    Directory of Open Access Journals (Sweden)

    Anna Poggesi

    2012-01-01

    Full Text Available Dementia is one of the most disabling conditions. Alzheimer’s disease and vascular dementia (VaD are the most frequent causes. Subcortical VaD is consequent to deep-brain small vessel disease (SVD and is the most frequent form of VaD. Its pathological hallmarks are ischemic white matter changes and lacunar infarcts. Degenerative and vascular changes often coexist, but mechanisms of interaction are incompletely understood. The term mild cognitive impairment defines a transitional state between normal ageing and dementia. Pre-dementia stages of VaD are also acknowledged (vascular mild cognitive impairment, VMCI. Progression relates mostly to the subcortical VaD type, but determinants of such transition are unknown. Variability of phenotypic expression is not fully explained by severity grade of lesions, as depicted by conventional MRI that is not sensitive to microstructural and metabolic alterations. Advanced neuroimaging techniques seem able to achieve this. Beside hypoperfusion, blood-brain-barrier dysfunction has been also demonstrated in subcortical VaD. The aim of the Vascular Mild Cognitive Impairment Tuscany Study is to expand knowledge about determinants of transition from mild cognitive impairment to dementia in patients with cerebral SVD. This paper summarizes the main aims and methodological aspects of this multicenter, ongoing, observational study enrolling patients affected by VMCI with SVD.

  7. Characteristics of alveolar bone associated with physiological movement of molar in mice: a histological and histochemical study.

    Science.gov (United States)

    Matsuda, Kie; Haga-Tsujimura, Maiko; Yoshie, Sumio; Shimomura-Kuroki, Junko

    2014-01-01

    Mouse molars undergo distal movement, during which new bone is formed at the mesial side of the tooth root whereas the preexisting bone is resorbed at the distal side of the root. However, there is little detailed information available regarding which of the bones that surround the tooth root are involved in physiological tooth movement. In the present study, we therefore aimed to investigate the precise morphological differences of the alveolar bone between the bone formation side of the tooth root, using routine histological procedures including silver impregnation, as well as by immunohistochemical analysis of alkaline phosphatase and tartrate-resistant acid phosphatase activity, and immunohistochemical analysis of the expression of the osteocyte markers dentin matrix protein 1, sclerostin, and fibroblast growth factor 23. Histochemical analysis indicated that bone formation by osteoblasts and bone resorption by osteoclasts occurred at the bone formation side and the bone resorption side, respectively. Osteocyte marker immunoreactivity of osteocytes at the surface of the bone close to the periodontal ligament differed at the bone formation and bone resorption sides. We also showed different specific features of osteocytic lacunar canalicular systems at the bone formation and bone resorption sides by using silver staining. This study suggests that the alveolar bone is different in the osteocyte nature between the bone formation side and the bone resorption side due to physiological distal movement of the mouse molar.

  8. Application of Diffusion Tensor Imaging Parameters to Detect Change in Longitudinal Studies in Cerebral Small Vessel Disease.

    Directory of Open Access Journals (Sweden)

    Eva Anna Zeestraten

    Full Text Available Cerebral small vessel disease (SVD is the major cause of vascular cognitive impairment, resulting in significant disability and reduced quality of life. Cognitive tests have been shown to be insensitive to change in longitudinal studies and, therefore, sensitive surrogate markers are needed to monitor disease progression and assess treatment effects in clinical trials. Diffusion tensor imaging (DTI is thought to offer great potential in this regard. Sensitivity of the various parameters that can be derived from DTI is however unknown. We aimed to evaluate the differential sensitivity of DTI markers to detect SVD progression, and to estimate sample sizes required to assess therapeutic interventions aimed at halting decline based on DTI data. We investigated 99 patients with symptomatic SVD, defined as clinical lacunar syndrome with MRI confirmation of a corresponding infarct as well as confluent white matter hyperintensities over a 3 year follow-up period. We evaluated change in DTI histogram parameters using linear mixed effect models and calculated sample size estimates. Over a three-year follow-up period we observed a decline in fractional anisotropy and increase in diffusivity in white matter tissue and most parameters changed significantly. Mean diffusivity peak height was the most sensitive marker for SVD progression as it had the smallest sample size estimate. This suggests disease progression can be monitored sensitively using DTI histogram analysis and confirms DTI's potential as surrogate marker for SVD.

  9. LACUNAR CONSTRUCTIONS “NOUN+ARTICLE” IN PUBLICIST-ORAL SPEECH OF ENGLISH AND GREEK

    Directory of Open Access Journals (Sweden)

    Fomenko L. N.

    2015-04-01

    Full Text Available This article describes some interesting facts of Modern English and Greek Grammar and pay our attention to extension of constructions “noun + article” without article in publicist-oral speech, where it should be. Our observations show some phenomena of evolution of system “noun + article”. This article is due to some cases of using articles, which we can’t often find in traditional native and foreign normal grammars. In English Grammar the ellipsis of article meets stylistic and syntax’s requirements. But there isn’t such limitation in Greek Grammar, that’s why on the one hand, we qualify the ellipsis of article as a realization of category determinacyindeterminacy, and on the other hand, we can see the generalization of the meaning of article. Illustrative materials are newspapers’ articles of classical British dialectical English and Dimotiki (oral New Greek.There are not only main rules of articles in periodical and oral speech, but also the meaning of nouns, which we can understand from surrounding context and geographical position, also as a style of periodical publications

  10. Significance of Haemodynamic and Haemostatic Factors in the Course of Different Manifestations of Cerebral Small Vessel Disease: The SHEF-CSVD Study—Study Rationale and Protocol

    Directory of Open Access Journals (Sweden)

    Jacek Staszewski

    2013-01-01

    Full Text Available Rationale. This paper describes the rationale and design of the SHEF-CSVD Study, which aims to determine the long-term clinical and radiological course of cerebral small vessel disease (CSVD and to evaluate haemostatic and haemodynamic prognostic factors of the condition. Design. This single-centre, prospective, non-interventional cohort study will follow 150 consecutive patients with different clinical manifestations of CSVD (lacunar ischaemic stroke, vascular dementia, vascular parkinsonism or spontaneous deep, intracerebral haemorrhage and 50 age- and sex-matched controls over a period of 24 months. The clinical and radiological course will be evaluated basing on a detailed neurological, neuropsychological and MRI examinations. Haemodynamic (cerebral vasoreactivity, 24 h blood pressure control and haemostatic factors (markers of endothelial and platelet dysfunction, brachial artery flow-mediated dilatation test will be determined. Discussion. The scheduled study will specifically address the issue of haemodynamic and haemostatic prognostic factors and their course over time in various clinical manifestations of CSVD. The findings may aid the development of prophylactic strategies and individualised treatment plans, which are critical during the early stages of the disease.

  11. Structure Analysis and Classification of Precipitation Cells by Fractal Geometry

    Institute of Scientific and Technical Information of China (English)

    Nafissa Azzaz; Boualem Haddad

    2014-01-01

    This paper analyzes the possibility to discriminate between convective precipitation and stratiform precipitation. This study aims to improve the measurement of rainfall from teledetection data obtained both on the ground and in space. For this, two parameters, fractal dimension and fractal lacunarity, are considered. To calculate the fractal dimension, we use the approach of box-counting and show that the fractal dimension differs between convectives cells and stratiforms ones. And then the fractal lacunarity parameter is calculated by using the sliding boxes algorithm. The study for all the regions shows that precipitation cells can be described by different lacunarities whatever the scale of analysis. We deduce that the two parameters, fractal dimension and fractal lacunarity, can be used to classify precipitations in convective regime and stratiform regime.

  12. Diabetes and hypertension markedly increased the risk of ischemic stroke associated with high serum resistin concentration in a general Japanese population: the Hisayama Study

    Directory of Open Access Journals (Sweden)

    Kawamura Ryoichi

    2009-11-01

    Full Text Available Abstract Background Resistin, secreted from adipocytes, causes insulin resistance in mice. The relationship between resistin and coronary artery disease is highly controversial, and the information regarding resistin and ischemic stroke is limited. In the present study, the association between serum resistin concentration and cardiovascular disease (CVD was investigated in a general Japanese population. Methods A total of 3,201 community-dwelling individuals aged 40 years or older (1,382 men and 1,819 women were divided into quintiles of serum resistin, and the association between resistin and CVD was examined cross-sectionally. The combined effect of either diabetes or hypertension and high serum resistin was also assessed. Serum resistin was measured using ELISA. Results Compared to those without CVD, age- and sex-adjusted mean serum resistin concentrations were greater in subjects with CVD (p = 0.002 or ischemic stroke (p Conclusion Elevated serum resistin concentration appears to be an independent risk factor for ischemic stroke, especially lacunar and atherothrombotic infarction in the general Japanese population. The combination of high resistin and the presence of either diabetes or hypertension increased the risk of ischemic stroke.

  13. A CLINICAL STUDY OF STROKE IN YOUNG

    Directory of Open Access Journals (Sweden)

    Kumbha Thulasi Ram

    2015-02-01

    Full Text Available NTRIDUCTION : Stroke is one of the important causes of morbidity and mortality all over the world. Incidence of stroke steadily increases with age. Experts are concerned of the emerging stroke epidemic in India. Stroke affecting the young has potentially devastating consequence son the individual and his family. Certain risk factors are unique to the young. I t needs more studies for identification and modification of risk factors. The study aims to evaluate clinical features, risk factors, etiology and mortality of stroke in young patients. METHODS : 74 young patients satisfying the inclusion criteria were included in this study. A detailed history was taken from young stroke patients, systemic examination and required investigations were done. Data was collected in standardized proforma and analysed. RESULTS: Stroke in young accounts for 7.95% of stroke cases of all age groups. The mean age of the patients was 34.66 ± 7.48 years. Among 74 patients, 47(63.51% were male and 27(36.49% were female. Seizures, decreased consciousness, speech involvement and motor deficit were observed in 33.78%, 44.59%, 22.97% and 100% of cases respectively. 82.43% patients had ischemic and 17.57% patients had hemorrhagic stroke. Among ischemic stroke, large artery atherosclerosis was 16.21%, tuberculous meningoencephalitis with vasculitis was 16.21%, lacunar stroke was 10.81%, CVT was 10.81% and cardio embolic stroke was 6.76%. Smoking (59.45%, alcoholism (58.10%, hypertension (43.24%, coronary artery disease (8.10%, diabetes mellitus (10.81%, elevated total cholesterol (25.67%, elevated low density lipo proteins (22.97%, elevated triglycerides (27.02% and low HDL (22.97% were important risk factors. Carotid doppler was abnormal in 9.45% of patients. 6.76% patients had mitral stenosis in echocardiogram. Low protein C and protein S were found in 1.35% of patients. Eight (10.81% patients died during the hospital stay. INTERPRETATION AND CONCLUSIONS: The major risk

  14. Pattern and Rate of Cognitive Decline in Cerebral Small Vessel Disease: A Prospective Study.

    Directory of Open Access Journals (Sweden)

    Andrew J Lawrence

    Full Text Available Cognitive impairment, predominantly affecting processing speed and executive function, is an important consequence of cerebral small vessel disease (SVD. To date, few longitudinal studies of cognition in SVD have been conducted. We determined the pattern and rate of cognitive decline in SVD and used the results to determine sample size calculations for clinical trials of interventions reducing cognitive decline.121 patients with MRI confirmed lacunar stroke and leukoaraiosis were enrolled into the prospective St George's Cognition And Neuroimaging in Stroke (SCANS study. Patients attended one baseline and three annual cognitive assessments providing 36 month follow-up data. Neuropsychological assessment comprised a battery of tests assessing working memory, long-term (episodic memory, processing speed and executive function. We calculated annualized change in cognition for the 98 patients who completed at least two time-points.Task performance was heterogeneous, but significant cognitive decline was found for the executive function index (p<0.007. Working memory and processing speed decreased numerically, but not significantly. The executive function composite score would require the smallest samples sizes for a treatment trial with an aim of halting decline, but this would still require over 2,000 patients per arm to detect a 30% difference with power of 0.8 over a three year follow-up.The pattern of cognitive decline seen in SVD over three years is consistent with the pattern of impairments at baseline. Rates of decline were slow and sample sizes would need to be large for clinical trials aimed at halting decline beyond initial diagnosis using cognitive scores as an outcome measure. This emphasizes the importance of more sensitive surrogate markers in this disease.

  15. Posture-Dependent Human 3He Lung Imaging in an Open Access MRI System: Initial Results

    CERN Document Server

    Tsai, L L; Li, C -H; Rosen, M S; Patz, S; Walsworth, R L

    2007-01-01

    The human lung and its functions are extremely sensitive to orientation and posture, and debate continues as to the role of gravity and the surrounding anatomy in determining lung function and heterogeneity of perfusion and ventilation. However, study of these effects is difficult. The conventional high-field magnets used for most hyperpolarized 3He MRI of the human lung, and most other common radiological imaging modalities including PET and CT, restrict subjects to lying horizontally, minimizing most gravitational effects. In this paper, we briefly review the motivation for posture-dependent studies of human lung function, and present initial imaging results of human lungs in the supine and vertical body orientations using inhaled hyperpolarized 3He gas and an open-access MRI instrument. The open geometry of this MRI system features a "walk-in" capability that permits subjects to be imaged in vertical and horizontal positions, and potentially allows for complete rotation of the orientation of the imaging su...

  16. Study on the Prevalence and Corelation of Carotid Atherosclerosis in Stroke Patients

    Institute of Scientific and Technical Information of China (English)

    Wei Hua; Wang Yongjun; Yah Zhenying

    2000-01-01

    Objective To assess the prevalence and severity of carotid atherosclerosis in stroke patients and the risk factors of carotid atherosclerosis. Methods Two hundred fifty-one ischemic stroke patients,46 ccrcbral hemorrhagc patients and 96 control subjects were entercd into this study. Sonographic assessment of the extracranial carotid arteries was performed in all patients. Diametcr. IMT, plaques and percentage ratio of lumen stenosis were observcd. Results (1)The prevalence of carotid plaqucs was prominent in stroke patients than the control subjects(63.0%vs 36.5%). (2)The prevalencc of lumen stenosis>50% in ischemic stroke patients was higher than the cerebral hemorrhage patients and control subjects (15.6% vs 4.3%. 2.1%).(3) The prevalence of severe carotid artery stcnosis(>75%) was promincnt in aged 61~70 years old patients.(4)Our data revealed 30% of the cortical infarction subgroup, 17.5%of the subcortical infarction subgroup, 17% of the lacunar infarction subgroup,8% of the vcrtibral-basilar artery infarction subgroup.2.8% of thc CT normal subgroup possessed carotid stcnosis >50%. (5)Age, diabetes mellitus and ApoAl(inversely) were independent predictors of the extracranial carotid atherosclcrosis. Discusssion (Ⅰ)There is close relation between extracraniai carotid atherosclerosis and ischemic cerebrovascular disease.(2)The extent of serious carotid artery stcnosis in aged patients was lower.(3)Thc severity of extracranial carotid artery atherosclerosis was prominent in patients with conical infarction. Conclusion There is a high prevalence of extracranial carotid atherosclerosis in Chinese stroke patients.

  17. Progression of Emphysema Evaluated by MRI Using Hyperpolarized 3He (HP 3He) Measurements in Patients with Alpha-1-Antitrypsin (A1AT) Deficiency Compared with CT and Lung Function Tests

    Energy Technology Data Exchange (ETDEWEB)

    Stavngaard, T.; Vejby Soegaard, L. (Danish Research Center for Magnetic Resonance, Copenhagen Univ. Hospital Hvidovre, Hvidovre (Denmark)); Batz, M. (Inst. of Physics, Johannes Gutenberg Univ., Mainz (Germany)); Schreiber, L.M. (Dept. of Interventional and Diagnostic Radiology, Johannes Gutenberg Univ. Medical School, Mainz (Germany)); Dirksen, A. (Dept. of Respiratory Medicine, Gentofte Hospital, Univ. of Copenhagen, Copenhagen (Denmark))

    2009-11-15

    Background: The progression of emphysema is traditionally measured by pulmonary function test, with forced expiratory volume in 1 s (FEV1) being the most accepted and used measurement. However, FEV1 is insensitive in detecting mild/slow progression of emphysema because of low reproducibility as compared to yearly decline. Purpose: To investigate the progression of emphysema over a period of 2 years using diffusion-weighted hyperpolarized (HP) 3He magnetic resonance imaging (MRI) in patients with alpha-1-antitrypsin (A1AT) deficiency. Material and Methods: Nine patients with severe A1AT deficiency were studied over a period of 2 years (baseline, year 1, and year 2) with HP 3He MRI using apparent diffusion coefficient (ADC), lung function tests (FEV1 and carbon monoxide lung diffusion capacity [DL,CO]), and computed tomography (CT) using densitometric parameters (15th percentile density [CT-PD15] and relative area of emphysema below -910 HU [CT-RA-910]). Results: Seven patients were scanned three times, one patient two times, and one patient only at baseline. The mean increase in ADC values from first to last HP 3He MR scanning was 3.8% (0.014 cm2/s [SD 0.024 cm2/s]; not significant). The time trends for FEV1, DL,CO, CT-PD15, and CT-RA-910 were all statistically significant. We found a high correlation between ADC and DL,CO (P<0.001). Conclusion: This pilot study indicates the possible use of nonionizing HP 3He MRI for monitoring the progression of emphysema. However, in the future, larger studies are needed to confirm these preliminary results

  18. Progression of Emphysema Evaluated by MRI Using Hyperpolarized 3He (HP 3He Measurements in Patients with Alpha-1-Antitrypsin (A1AT) Deficiency Compared with CT and Lung Function Tests

    International Nuclear Information System (INIS)

    Background: The progression of emphysema is traditionally measured by pulmonary function test, with forced expiratory volume in 1 s (FEV1) being the most accepted and used measurement. However, FEV1 is insensitive in detecting mild/slow progression of emphysema because of low reproducibility as compared to yearly decline. Purpose: To investigate the progression of emphysema over a period of 2 years using diffusion-weighted hyperpolarized (HP) 3He magnetic resonance imaging (MRI) in patients with alpha-1-antitrypsin (A1AT) deficiency. Material and Methods: Nine patients with severe A1AT deficiency were studied over a period of 2 years (baseline, year 1, and year 2) with HP 3He MRI using apparent diffusion coefficient (ADC), lung function tests (FEV1 and carbon monoxide lung diffusion capacity [DL,CO]), and computed tomography (CT) using densitometric parameters (15th percentile density [CT-PD15] and relative area of emphysema below -910 HU [CT-RA-910]). Results: Seven patients were scanned three times, one patient two times, and one patient only at baseline. The mean increase in ADC values from first to last HP 3He MR scanning was 3.8% (0.014 cm2/s [SD 0.024 cm2/s]; not significant). The time trends for FEV1, DL,CO, CT-PD15, and CT-RA-910 were all statistically significant. We found a high correlation between ADC and DL,CO (P3He MRI for monitoring the progression of emphysema. However, in the future, larger studies are needed to confirm these preliminary results

  19. Assessment of lung disease in children with cystic fibrosis using hyperpolarized 3-Helium MRI: comparison with Shwachman score, Chrispin-Norman score and spirometry

    International Nuclear Information System (INIS)

    This study assesses the feasibility of hyperpolarized 3-Helium MRI in children with cystic fibrosis (CF) and correlates the findings with standard clinical parameters based on chest radiograph (CXR) and pulmonary function tests (PFT). An uncontrolled, observational study in eighteen children with cystic fibrosis aged 5 - 17 years (median 12.1 years), with different severity of disease was carried out. All subjects underwent routine clinical assessment including PFT and standard auxology; CXR was obtained and Shwachman and Chrispin-Norman scores calculated. Hyperpolarized 3-He magnetic resonance imaging (MRI) was carried out using a spin-exchange polarizer and a whole body 1.5 T scanner. Ventilation distribution images were obtained during a 21-second breath-hold and scored according to previously defined criteria. Spearman's non-parametric correlations test was performed to assess for statistical significance at the p<0.05 level. The children tolerated the procedure well. No desaturation events were observed during 3-He MRI. A significant, albeit moderate, correlation was found between MRI score and FEV1% predicted (r=-0.41; p=0.047) and FVC% predicted (r=-0.42; p=0.04), while there were trends of correlations between Shwachman score and MRI score (r=-0.38; p=0.06) and Shwachman score and FEV1% predicted (r=0.39; p=0.055). The feasibility of hyperpolarized 3-He MRI in children with CF was demonstrated. MRI appears to be able to demonstrate functional lung changes, although correlations with routine clinical tests are only moderate to poor. This non-ionising radiation technique could be useful for monitoring lung disease and assessing therapy in this patient population. (orig.)

  20. Assessment of lung disease in children with cystic fibrosis using hyperpolarized 3-Helium MRI: comparison with Shwachman score, Chrispin-Norman score and spirometry

    Energy Technology Data Exchange (ETDEWEB)

    Beek, Edwin J.R. van [University of Sheffield, Unit of Academic Radiology, Sheffield (United Kingdom); University of Iowa, Department of Radiology, Carver College of Medicine, Iowa City (United States); University of Iowa, Department of Radiology, Iowa City, IA (United States); Hill, Catherine; Woodhouse, Neil; Fichele, Stanislao; Fleming, Sally; Wild, Jim M. [University of Sheffield, Unit of Academic Radiology, Sheffield (United Kingdom); Howe, Bridget; Bott, Sandra; Taylor, Christopher J. [University of Sheffield, Academic Unit of Child Health, Sheffield (United Kingdom)

    2007-04-15

    This study assesses the feasibility of hyperpolarized 3-Helium MRI in children with cystic fibrosis (CF) and correlates the findings with standard clinical parameters based on chest radiograph (CXR) and pulmonary function tests (PFT). An uncontrolled, observational study in eighteen children with cystic fibrosis aged 5 - 17 years (median 12.1 years), with different severity of disease was carried out. All subjects underwent routine clinical assessment including PFT and standard auxology; CXR was obtained and Shwachman and Chrispin-Norman scores calculated. Hyperpolarized 3-He magnetic resonance imaging (MRI) was carried out using a spin-exchange polarizer and a whole body 1.5 T scanner. Ventilation distribution images were obtained during a 21-second breath-hold and scored according to previously defined criteria. Spearman's non-parametric correlations test was performed to assess for statistical significance at the p<0.05 level. The children tolerated the procedure well. No desaturation events were observed during 3-He MRI. A significant, albeit moderate, correlation was found between MRI score and FEV1% predicted (r=-0.41; p=0.047) and FVC% predicted (r=-0.42; p=0.04), while there were trends of correlations between Shwachman score and MRI score (r=-0.38; p=0.06) and Shwachman score and FEV1% predicted (r=0.39; p=0.055). The feasibility of hyperpolarized 3-He MRI in children with CF was demonstrated. MRI appears to be able to demonstrate functional lung changes, although correlations with routine clinical tests are only moderate to poor. This non-ionising radiation technique could be useful for monitoring lung disease and assessing therapy in this patient population. (orig.)

  1. Cerebral Small Vessel Disease and Risk of Death, Ischemic Stroke, and Cardiac Complications in Patients With Atherosclerotic Disease The Second Manifestations of ARTerial disease-Magnetic Resonance (SMART-MR) Study

    NARCIS (Netherlands)

    M.M.A. Conijn; R.P. Kloppenborg; A. Algra; W.P.T.M. Mali; L.J. Kappelle; K.L. Vincken; Y. van der Graaf; M.I. Geerlings

    2011-01-01

    Background and Purpose-Cerebral small vessel disease may be related to vascular and nonvascular pathology. We assessed whether lacunar infarcts and white matter lesions on MRI increased the risk of vascular and nonvascular death and future vascular events in patients with atherosclerotic disease. Me

  2. Quantitative {sup 1}H and hyperpolarized {sup 3}He magnetic resonance imaging: Comparison in chronic obstructive pulmonary disease and healthy never-smokers

    Energy Technology Data Exchange (ETDEWEB)

    Owrangi, Amir M., E-mail: aowrangi@robats.ca [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Canada N6A 5K8 (Canada); Graduate Program in Biomedical Engineering, The University of Western Ontario, London (Canada); Wang, Jian X., E-mail: jxwang@robats.ca [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Canada N6A 5K8 (Canada); Applied Science Laboratories, General Electric Healthcare (Canada); Wheatley, Andrew, E-mail: awheat@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Canada N6A 5K8 (Canada); McCormack, David G., E-mail: David.Mccormack@lhsc.on.ca [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Canada N6A 5K8 (Canada); Division of Respirology, Department of Medicine, The University of Western Ontario, London (Canada); Parraga, Grace, E-mail: gparraga@robats.ca [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Canada N6A 5K8 (Canada); Graduate Program in Biomedical Engineering, The University of Western Ontario, London (Canada); Department of Medical Imaging, The University of Western Ontario, London (Canada); Department of Medical Biophysics, The University of Western Ontario, London (Canada)

    2014-01-15

    Objective: The aim of this study was to quantitatively evaluate the relationship between short echo time pulmonary {sup 1}H magnetic resonance imaging (MRI) signal intensity (SI) and {sup 3}He MRI apparent diffusion coefficients (ADC), high-resolution computed tomography (CT) measurements of emphysema, and pulmonary function measurements. Materials and methods: Nine healthy never-smokers and 11 COPD subjects underwent same-day plethysmography, spirometry, short echo time ((TE) = 1.2 ms) {sup 1}H and diffusion-weighted hyperpolarized {sup 3}He MRI (b = 1.6 s/cm{sup 2}) at 3.0 T. In addition, for COPD subjects only, CT densitometry was also performed. Results: Mean {sup 1}H SI was significantly greater for never-smokers (12.1 ± 1.1 arbitrary units (AU)) compared to COPD subjects (10.9 ± 1.3 AU, p = 0.04). The {sup 1}H SI AP-gradient was also significantly greater for never-smokers (0.40 AU/cm, R{sup 2} = 0.94) compared to COPD subjects (0.29 AU/cm, R{sup 2} = 0.968, p = 0.05). There was a significant correlation between {sup 1}H SI and {sup 3}He ADC (r = −0.58, p = 0.008) and significant correlations between {sup 1}H MR SI and CT measurements of emphysema (RA{sub 950}, r = −0.69, p = 0.02 and HU{sub 15}, r = 0.66, p = 0.03). Conclusions: The significant and moderately strong relationship between {sup 1}H SI and {sup 3}He ADC, as well as between {sup 1}H SI and CT measurements of emphysema suggests that these imaging methods and measurements may be quantifying similar tissue changes in COPD and that pulmonary {sup 1}H SI may be used to monitor emphysema as a complement to CT and noble gas MRI.

  3. Quantitative 1H and hyperpolarized 3He magnetic resonance imaging: Comparison in chronic obstructive pulmonary disease and healthy never-smokers

    International Nuclear Information System (INIS)

    Objective: The aim of this study was to quantitatively evaluate the relationship between short echo time pulmonary 1H magnetic resonance imaging (MRI) signal intensity (SI) and 3He MRI apparent diffusion coefficients (ADC), high-resolution computed tomography (CT) measurements of emphysema, and pulmonary function measurements. Materials and methods: Nine healthy never-smokers and 11 COPD subjects underwent same-day plethysmography, spirometry, short echo time ((TE) = 1.2 ms) 1H and diffusion-weighted hyperpolarized 3He MRI (b = 1.6 s/cm2) at 3.0 T. In addition, for COPD subjects only, CT densitometry was also performed. Results: Mean 1H SI was significantly greater for never-smokers (12.1 ± 1.1 arbitrary units (AU)) compared to COPD subjects (10.9 ± 1.3 AU, p = 0.04). The 1H SI AP-gradient was also significantly greater for never-smokers (0.40 AU/cm, R2 = 0.94) compared to COPD subjects (0.29 AU/cm, R2 = 0.968, p = 0.05). There was a significant correlation between 1H SI and 3He ADC (r = −0.58, p = 0.008) and significant correlations between 1H MR SI and CT measurements of emphysema (RA950, r = −0.69, p = 0.02 and HU15, r = 0.66, p = 0.03). Conclusions: The significant and moderately strong relationship between 1H SI and 3He ADC, as well as between 1H SI and CT measurements of emphysema suggests that these imaging methods and measurements may be quantifying similar tissue changes in COPD and that pulmonary 1H SI may be used to monitor emphysema as a complement to CT and noble gas MRI

  4. Cortical changes in cerebral small vessel diseases: a 3D MRI study of cortical morphology in CADASIL

    Energy Technology Data Exchange (ETDEWEB)

    Jouvent, E.; Bousser, M.G.; Chabriat, H. [CHU Lariboisiere, AP HP, INSERM, UMR 740, Dept Neurol, Lariboisiere (France); Jouvent, E.; Bousser, M.G.; Chabriat, H. [Univ Paris 07, F-75221 Paris 05 (France); Porcher, R. [Hop St Louis, AP-HP, Dept Biostat, St Louis (France); Viswanathan, A. [Massachusetts Gen Hosp, Dept Neurol, Boston, MA 02114 (United States); Viswanathan, A. [Massachusetts Gen Hosp, Clin Trials Unit, Boston, MA 02114 (United States); Viswanathan, A. [Harvard Univ, Sch Med, Boston, MA (United States); O' Sullivan, M.; Dichgans, M. [Univ Munich, Klinikum Grosshadern, Dept Neurol, D-81377 Munich (Germany); Guichard, J.P. [CHU Lariboisiere, AP-HP, Dept Neuroradiol, Lariboisiere (France)

    2008-07-01

    Brain atrophy represents a key marker of disease progression in cerebrovascular disorders. The 3D changes of cortex morphology occurring during the course of small vessel diseases of the brain (SVDB) remain poorly understood. The objective of this study was to assess the changes affecting depth and surface area of cortical sulci and their clinical and radiological correlates in a cohort of patients with cerebral autosomal dominant arteriolopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a genetic SVDB. Data were obtained from a series of 69 CADASIL patients. Validated methods were used to determine depth and surface area of four cortical sulci. The ratio of brain to intracranial cavity volumes (brain parenchymal fraction-BPF), volume of lacunar lesions (LL) and of white matter hyper-intensities, number of cerebral micro-haemorrhages, and mean apparent diffusion coefficient were also measured. Association between depth and surface area of the cortical sulci and BPF, clinical status and subcortical MRI lesions were tested. Depth and surface area of cortical sulci obtained in 54 patients were strongly correlated with both cognitive score and disability scales. Depth was related to the extent of subcortical lesions, surface area was related only to age. In additional analyses, the depth of the cingular sulcus was independently associated with the volume of LL (P 0.001), and that of the superior frontal sulcus with the mean apparent diffusion coefficient (P 0.003). In CADASIL, important morphological changes of cortical sulci occur in association with clinical worsening,extension of subcortical tissue damage and progression of global cerebral atrophy. These results suggest that the examination of cortical morphology may be of high clinical relevance in SVDB. (authors)

  5. Five-year prognosis after mild to moderate ischemic stroke by stroke subtype: a multi-clinic registry study.

    Directory of Open Access Journals (Sweden)

    Yumei Lv

    Full Text Available BACKGROUND AND PURPOSE: Mild to moderate ischemic stroke is a common presentation in the outpatient setting. Among the various subtypes of stroke, lacunar infarction (LI is generally very common. Currently, little is known about the long-term prognosis and factors associated with the prognosis between LI and non-LI. This study aims to compare the risk of death and acute cardiovascular events between patients with LI and non-LI, and identify potential risk factors associated with these outcomes. METHODS: A total of 710 first-ever ischemic stroke patients (LI: 474, non-LI: 263 from 18 clinics were recruited consecutively from 2003 to 2004. They were prospectively followed-up until the end of 2008. Hazard ratios and 95% confidence intervals were calculated using multivariable Cox proportional hazards regression. RESULTS: After a 5-year follow up, 54 deaths and 96 acute cardiovascular events occurred. Recurrent stroke was the most common cause of death (19 cases, 35.18% and new acute cardiovascular events (75 cases, 78.13%. There were no significant differences between patients with LI and non-LI in their risks of death, new cardiovascular events, and recurrent stroke after adjusting for age, sex, hypertension, diabetes, cardiac diseases, body mass index, dyslipidemia, smoking, alcohol consumption, ADL dependence, and depressive symptoms. Among the modifiable risk factors, diabetes, hypertension, ADL dependency, and symptoms of depression were independent predictors of poor outcomes in patients with LI. In non-LI patients, however, no modifiable risk factors were detected for poor outcomes. CONCLUSION: Long-term outcomes did not differ significantly between LI and non-LI patients. Detecting and managing vascular risk factors and depression as well as functional rehabilitation may improve the prognoses of LI patients.

  6. Studies on intracranial collateral circulation with multi-slice CT angiography in patients with symptomatic cerebral artery stenosis

    Directory of Open Access Journals (Sweden)

    Shu-qing ZHOU

    2011-06-01

    Full Text Available Objective To explore the features of intracranial collateral circulation in patients with symptomatic cerebral artery stenosis.Method Ninety-four patients with ischemic cerebrovascular disease admitted from Apr.2004 to Jun.2009 were involved in present study.All the patients were examined with cerebral multi-slice CT angiography,and the features of cerebral artery stenosis and intracranial collateral circulation were evaluated using maximum intensity projection(MIP and volume rendering(VR images of CT angiography.Result Of the 94 patients involved,48 were diagnosed as cerebral artery stenosis,including 29 cases of cerebral infarction,18 of transient ischemic attack(TIA and 1 of moyamoya disease(MMD.Among the 14 cases of severe cerebral artery stenosis or occlusion,cerebral infarction was found in 6 cases with lesser intracranial collateral vessels(including massive cerebral infarction in 4 cases and watershed infarction in 2 cases,and focal infarction of central semi-ovale in 1 case and TIA in 7 cases were found with abundant intracranial collateral vessels.Multiple lacunar infarction was found in 22 cases of mild or moderate cerebral artery stenosis,but there was no significant correlation between the stenosed arteries and infarction sites.Abundant intracranial collateral vessels were found in one patient with Moyamoya disease but no infarction was observed.Conclusions Intracranial collateral circulation plays an important role of compensation in patients with severe cerebral artery stenosis or occlusion.Cerebral angiography with multi-slice CT is of great significance in evaluation of cerebral artery stenosis and intracranial collateral circulation.

  7. Brain MRI findings of carbon disulfide poisoning

    International Nuclear Information System (INIS)

    To evaluate the findings of brain MRI in patients with carbon disulfide poisoning. Ninety-one patients who had suffered carbon disulfide poisoning [male:female=87:4; age, 32-74 (mean 53.3) years] were included in this study. To determine the extent of white matter hyperintensity (Grade 0-V) and lacunar infarction, T2-weighted MR imaging of the brain was performed. T2-weighted images depicted white matter hyperintensity in 70 patients (76.9%) and lacunar infarcts in 27 (29.7%). In these patients, the prevalent findings at T2-weighted MR imaging of the brain were white matter hyperintensity and lacunar infarcts. Disturbance of the cardiovascular system by carbon disulfide might account for these results

  8. Infarction in the territory of the anterior cerebral artery: clinical study of 51 patients

    Directory of Open Access Journals (Sweden)

    Oliveres Montserrat

    2009-07-01

    Full Text Available Abstract Background Little is known about clinical features and prognosis of patients with ischaemic stroke caused by infarction in the territory of the anterior cerebral artery (ACA. This single centre, retrospective study was conducted with the following objectives: a to describe the clinical characteristics and short-term outcome of stroke patients with ACA infarction as compared with that of patients with ischaemic stroke due to middle cerebral artery (MCA and posterior cerebral artery (PCA infarctions, and b to identify predictors of ACA stroke. Methods Fifty-one patients with ACA stroke were included in the "Sagrat Cor Hospital of Barcelona Stroke Registry" during a period of 19 years (1986–2004. Data from stroke patients are entered in the stroke registry following a standardized protocol with 161 items regarding demographics, risk factors, clinical features, laboratory and neuroimaging data, complications and outcome. The characteristics of these 51 patients with ACA stroke were compared with those of the 1355 patients with MCA infarctions and 232 patients with PCA infarctions included in the registry. Results Infarctions of the ACA accounted for 1.3% of all cases of stroke (n = 3808 and 1.8% of cerebral infarctions (n = 2704. Stroke subtypes included cardioembolic infarction in 45.1% of patients, atherothrombotic infarction in 29.4%, lacunar infarct in 11.8%, infarct of unknown cause in 11.8% and infarction of unusual aetiology in 2%. In-hospital mortality was 7.8% (n = 4. Only 5 (9.8% patients were symptom-free at hospital discharge. Speech disturbances (odds ratio [OR] = 0.48 and altered consciousness (OR = 0.31 were independent variables of ACA stroke in comparison with MCA infarction, whereas limb weakness (OR = 9.11, cardioembolism as stroke mechanism (OR = 2.49 and sensory deficit (OR = 0.35 were independent variables associated with ACA stroke in comparison with PCA infarction. Conclusion Cardioembolism is the main cause of

  9. The poro-viscoelastic properties of trabecular bone: a micro computed tomography-based finite element study.

    Science.gov (United States)

    Sandino, Clara; McErlain, David D; Schipilow, John; Boyd, Steven K

    2015-04-01

    Bone is a porous structure with a solid phase that contains hydroxyapatite and collagen. Due to its composition, bone is often represented either as a poroelastic or as a viscoelastic material; however, the poro-viscoelastic formulation that allows integrating the effect of both the fluid flow and the collagen on the mechanical response of the tissue, has not been applied yet. The objective of this study was to develop a micro computed tomography (µCT)-based finite element (FE) model of trabecular bone that includes both the poroelastic and the viscoelastic nature of the tissue. Cubes of trabecular bone (N=25) from human distal tibia were scanned with µCT and stress relaxation experiments were conducted. The µCT images were the basis for sample specific FE models, and the stress relaxation experiments were simulated applying a poro-viscoelastic formulation. The model considers two scales of the tissue: the intertrabecular pore and the lacunar-canalicular pore scales. Independent viscoelastic and poroelastic models were also developed to determine their contribution to the poro-viscoelastic model. All the experiments exhibited a similar relaxation trend. The average reaction force before relaxation was 9.28 × 10(2)N (SD ± 5.11 × 10(2)N), and after relaxation was 4.69 × 10(2)N (SD ± 2.88 × 10(2)N). The slope of the regression line between the force before and after relaxation was 1.92 (R(2)=0.96). The poro-viscoelastic models captured 49% of the variability of the experimental data before relaxation and 33% after relaxation. The relaxation predicted with viscoelastic models was similar to the poro-viscoelastic ones; however, the poroelastic formulation underestimated the reaction force before relaxation. These data suggest that the contribution of viscoelasticity (fluid flow-independent mechanism) to the mechanical response of the tissue is significantly greater than the contribution of the poroelasticity (fluid flow-dependent mechanism). PMID:25591049

  10. Cerebral Microbleeds and White Matter Hyperintensities in Cognitively Healthy Elderly: A Cross-Sectional Cohort Study Evaluating the Effect of Arterial Stiffness

    Directory of Open Access Journals (Sweden)

    Anna-Märta Gustavsson

    2015-05-01

    Full Text Available Background: Arterial stiffness reflects the ageing processes in the vascular system, and studies have shown an association between reduced cognitive function and cerebral small vessel disease. Small vessel disease can be visualized as white matter hyperintensities (WMH and lacunar infarcts but also as cerebral microbleeds on brain magnetic resonance imaging (MRI. We aimed to investigate if arterial stiffness influences the presence of microbleeds, WMH and cognitive function in a population of cognitively healthy elderly. Methods: The study population is part of the Swedish BioFinder study and consisted of 208 individuals without any symptoms of cognitive impairment, who scored >27 points on the Mini-Mental State Examination. The participants (mean age, 72 years; 59% women underwent MRI of the brain with visual rating of microbleeds and WMH. Arterial stiffness was measured with carotid-femoral pulse wave velocity (cfPWV. Eight cognitive tests covering different cognitive domains were performed. Results: Microbleeds were detected in 12% and WMH in 31% of the participants. Mean (±standard deviation, SD cfPWV was 10.0 (±2.0 m/s. There was no association between the presence of microbleeds and arterial stiffness. There was a positive association between arterial stiffness and WMH independent of age or sex (odds ratio, 1.58; 95% confidence interval, 1.04-2.40, p 0.05. Cognitive performance was not associated with microbleeds, but individuals with WMH performed slightly worse than those without WMH on the Symbol Digit Modalities Test (mean ± SD, 35 ± 7.8 vs. 39 ± 8.1, p Conclusions: Arterial stiffness was not associated with the presence of cerebral microbleeds or cognitive function in cognitively healthy elderly. However, arterial stiffness was related to the presence of WMH, but the association was attenuated when multiple adjustments were made. There was a weak negative association between WMH and performance in one specific test of attention

  11. Change over time in brain computed tomographic and magnetic resonance imaging findings in healthy elderly persons. A 10 year prospective study

    International Nuclear Information System (INIS)

    Early detection, treatment and prevention of dementia have become increasingly important as the population ages. I have performed a follow-up study of changes in the brains of healthy elderly persons with computed tomography (CT) and magnetic resonance imaging (MRI) since 1982. One hundred thirty-three healthy elderly volunteers were first examined in 1982 with CT or MRI, electroencephalography, the Benton Visual Retention Test (BVRT), blood pressure measurement, and interview. Subsequent examinations were done in 1986, 1989, and 1992. On CT, microinfarctions were found in 15.0% of subjects in 1982 and in 13.0% in 1986, and periventricular lucency (PVL) was found in 6.0% and 8.3%. The most frequent findings were vascular changes, which were observed in six persons (5.6%), followed by PVL, which was found in four persons (3.7%). Thus, vascular changes became more pronounced during the follow-up period. Lesions with high signal intensity on T2-weighted images (T2HSI) were found in 69.5% of subjects and increased in prevalence with age in the 1989 study. Such T2HSI lesions were found most frequently in the basal ganglia (61.9%), followed by the thalamus (39.0%), parietal lobe (37.0%), temporal lobe (12.7%), and the pons (8.5%). Of these lesions, lacunar infarctions showed low signal intensity on T1-weighted images and were found in 24.6% of subjects; their prevalence also increased with age. Results of BVRT were closely correlated with T2HSI lesions, suggesting that T2HSIs lesions may affect cognitive function. By 1992, 10 years after the start of the study, 34 (25.6%) of subjects had died and 19 (14.3%) had become demented. Subjects were divided into surviving and dead groups and dementia and non-dementia groups. Findings on CT and BVRT in this study have provided clear clinical indices of death and dementia, especially maximal width of third ventricule in impairment of the diagnosis of dementia. (author)

  12. Land-Use and Land-Cover Mapping Using a Gradable Classification Method

    Directory of Open Access Journals (Sweden)

    Keigo Kitada

    2012-05-01

    Full Text Available Conventional spectral-based classification methods have significant limitations in the digital classification of urban land-use and land-cover classes from high-resolution remotely sensed data because of the lack of consideration given to the spatial properties of images. To recognize the complex distribution of urban features in high-resolution image data, texture information consisting of a group of pixels should be considered. Lacunarity is an index used to characterize different texture appearances. It is often reported that the land-use and land-cover in urban areas can be effectively classified using the lacunarity index with high-resolution images. However, the applicability of the maximum-likelihood approach for hybrid analysis has not been reported. A more effective approach that employs the original spectral data and lacunarity index can be expected to improve the accuracy of the classification. A new classification procedure referred to as “gradable classification method” is proposed in this study. This method improves the classification accuracy in incremental steps. The proposed classification approach integrates several classification maps created from original images and lacunarity maps, which consist of lacnarity values, to create a new classification map. The results of this study confirm the suitability of the gradable classification approach, which produced a higher overall accuracy (68% and kappa coefficient (0.64 than those (65% and 0.60, respectively obtained with the maximum-likelihood approach.

  13. Relation of cerebral small-vessel disease and brain atrophy to mild Parkinsonism in the elderly.

    Science.gov (United States)

    Reitz, Christiane; Trenkwalder, Claudia; Kretzschmar, Konrad; Roesler, Andreas; V Eckardstein, Arnold; Berger, Klaus

    2006-11-01

    The association between cerebral small-vessel disease, brain atrophy, and the risk and severity of mild parkinsonian signs (MPS) remains unclear. The objective of this study is to examine the effect of lacunar brain infarcts, cerebral white matter lesions (WMLs), and cortical atrophy on the risk and severity of MPS. This study is a cross-sectional community-based cohort study comprising 268 subjects, 65 to 83 years of age, residing in the Augsburg region of southern Germany, and without contraindications for magnetic resonance imaging (MRI) of the brain. Main outcome measures. Subcortical and periventricular WMLs, lacunar brain infarcts, and cortical atrophy determined using a standardized MRI protocol developed for the Rotterdam Scan Study and an established rating scale. MPS, assessed in a standardized neurological examination and based on the Unified Parkinson's Disease Rating Scale motor scale. Lacunar brain infarcts and large subcortical white matter lesions were associated with an elevated risk of resting tremor. More severe cortical atrophy was related to an increased risk of rigidity and bradykinesia. In a linear regression analysis relating each individual MRI measurement with the severity of MPS, the number of lacunar brain infarcts and the degree of brain atrophy were correlated with the severity of resting tremor, whereas the size of subcortical and periventricular WMLs was correlated with the severity of rigidity. A higher degree of brain atrophy was associated with increased severity of either cardinal sign. In our study, presence and volume of lacunar brain infarcts, cerebral WMLs, and cortical atrophy were associated with the risk as well as severity of MPS. Determining the presence of these brain changes using brain imaging might contribute to identify persons at risk for MPS.

  14. Impact of Non-Invasively Induced Motor Deficits on Tibial Cortical Properties in Mutant Lurcher Mice.

    Directory of Open Access Journals (Sweden)

    Alena Jindrová

    Full Text Available It has been shown that Lurcher mutant mice have significantly altered motor abilities, regarding their motor coordination and muscular strength because of olivorecebellar degeneration. We assessed the response of the cross-sectional geometry and lacuno-canalicular network properties of the tibial mid-diaphyseal cortical bone to motor differences between Lurcher and wild-type (WT male mice from the B6CBA strain. The first data set used in the cross-sectional geometry analysis consists of 16 mice of 4 months of age and 32 mice of 9 months of age. The second data set used in the lacunar-canalicular network analysis consists of 10 mice of 4 months of age. We compared two cross-sectional geometry and four lacunar-canalicular properties by I-region using the maximum and minimum second moment of area and anatomical orientation as well as H-regions using histological differences within a cross section. We identified inconsistent differences in the studied cross-sectional geometry properties between Lurcher and WT mice. The biggest significant difference between Lurcher and WT mice is found in the number of canaliculi, whereas in the other studied properties are only limited. Lurcher mice exhibit an increased number of canaliculi (p < 0.01 in all studied regions compared with the WT controls. The number of canaliculi is also negatively correlated with the distance from the centroid in the Lurcher and positively correlated in the WT mice. When the Lurcher and WT sample is pooled, the number of canaliculi and lacunar volume is increased in the posterior Imax region, and in addition, midcortical H-region exhibit lower number of canaliculi, lacuna to lacuna distance and increased lacunar volume. Our results indicate, that the importance of precise sample selection within cross sections in future studies is highlighted because of the histological heterogeneity of lacunar-canalicular network properties within the I-region and H-region in the mouse cortical

  15. Two and three-dimensional segmentation of hyperpolarized 3He magnetic resonance imaging of pulmonary gas distribution

    Science.gov (United States)

    Heydarian, Mohammadreza; Kirby, Miranda; Wheatley, Andrew; Fenster, Aaron; Parraga, Grace

    2012-03-01

    A semi-automated method for generating hyperpolarized helium-3 (3He) measurements of individual slice (2D) or whole lung (3D) gas distribution was developed. 3He MRI functional images were segmented using two-dimensional (2D) and three-dimensional (3D) hierarchical K-means clustering of the 3He MRI signal and in addition a seeded region-growing algorithm was employed for segmentation of the 1H MRI thoracic cavity volume. 3He MRI pulmonary function measurements were generated following two-dimensional landmark-based non-rigid registration of the 3He and 1H pulmonary images. We applied this method to MRI of healthy subjects and subjects with chronic obstructive lung disease (COPD). The results of hierarchical K-means 2D and 3D segmentation were compared to an expert observer's manual segmentation results using linear regression, Pearson correlations and the Dice similarity coefficient. 2D hierarchical K-means segmentation of ventilation volume (VV) and ventilation defect volume (VDV) was strongly and significantly correlated with manual measurements (VV: r=0.98, phierarchical K-means segmentation of VV and VDV was also strongly and significantly correlated with manual measurements (VV: r=0.98, psemi-automated segmentation of 3He MRI gas distribution provides a way to generate novel pulmonary function measurements.

  16. Leaf anatomy of Gaillardia cabrerae (Asteraceae: Basic plan and comparative study of two contrasting habitat populations Anatomía foliar de Gaillardia cabrerae (Asteraceae: plan básico y estudio comparativo de dos poblaciones de hábitats contrastantes

    Directory of Open Access Journals (Sweden)

    Laura Beinticinco

    2011-06-01

    Full Text Available This study evaluates the leaf anatomy pattern of Gaillardia cabrerae Covas, an exclusive endemic camephyte from the Lihué Calel National Park, province of La Pampa, Argentina. Leaf cross sections and peelings of plants growing in two different populations were used to determine the basic leaf anatomy patterns and to estimate the influence of growth conditions in the two microhabitats. The analysis showed differences in epidermal cells area, stomata density and main diameter, lacunar parenchyma cells and central vascular bundle diameter and palisade parenchyma cells dimensions. These aspects might be reflecting environmental conditions of the populations, especially sun exposure and soil moisture. The results provide information on the relationship of the species to its environment, which could be used in the establishment of conservation policies.Gaillardia cabrerae Covas es un caméfito endémico del Parque Nacional Lihué Calel. En este estudio se evalúan características anatómicas de individuos de dos poblaciones provenientes de diferentes microhábitats de las Sierras de Lihué Calel. La información proporcionada es importante para entender las condiciones de vida de la especie y provee información inherente para establecer planes de conservación. Mediante cortes transversales y la técnica de peeling fue posible determinar el plan básico de la anatomía foliar y también verificar diferencias significativas en el área de células epidérmicas, densidad estomática, diámetro mayor de los estomas, diámetro de células del parénquima lagunar y del haz vascular central y en las dimensiones de las células del parénquima en empalizada. Las condiciones ambientales a las cuales estas poblaciones están sometidas, especialmente la exposición solar y la humedad del suelo son posibles factores que podrían explicar las diferencias detectadas en la anatomía foliar para ambas poblaciones.

  17. Clinical study of the relationship between arteriosclerosis obliterans (ASO) and cerebral infarction

    International Nuclear Information System (INIS)

    To clarify the relationship between arteriosclerosis obliterans (ASO) and cerebral infarction (CI), brain CT was performed and the risk factors for atherosclerosis were assessed. Thirty-five male and 5 female patients with intermittent claudication and/or leg ulceration were angiographically diagnosed as having ASO. According to CT findings, these patients were divided into three groups [no low-density areas (NLDA), hemorrhage, and infarction (CI)]. CI was subdivided as lacunar, cortical, and watershed infarction. Thirteen patients were in the NLDA group and 26 in the CI group (17 lacunar, 3 cortical and 6 mixed infarcts), indicating a CI incidence of 65%. Comparing the risk factors of the CI group with those of the NLDA group, hypertension (53.8%), diabetes (34.6%), and cigarette smoking (69.2%) was often seen in the CI group, although hypercholesterolemia (53.8%) and ischemic heart disease (42.3%) was the same in both groups. Multivariate analysis revealed that smoking had the strongest effect on the occurrence of CI in ASO patients. Furthermore, the number of combined risk factors (hypertension, diabetes, smoking, hypercholesterolemia) had a significant positive correlation with cortical infarction. As to the chronological relationship between the onset of ASO and CI, CI was present in 14 of 27 ASO patients on CT when the ischemic leg symptoms appeared, while symptomatic cortical infarction preceded ASO in 5 patients. CI patients increased gradually over a decade to 26 out of 40, among whom 16 patients with lacunae had silent infarcts. These findings suggested that ASO is frequently associated with CI, not only due to atherosclerosis of the main trunks of the cerebral vessels, but also due to arteriolosclerosis of the perforating arteries. (author)

  18. Calcium Response in Osteocytic Networks under Steady and Oscillatory Fluid Flow

    OpenAIRE

    Lu, X. Lucas; Huo, Bo; Park, Miri; Guo, X. Edward

    2012-01-01

    The fluid flow in the lacunar-canalicular system of bone is an essential mechanical stimulation on the osteocyte networks. Due to the complexity of human physical activities, the fluid shear stress on osteocyte bodies and processes consists of both steady and oscillatory components. In this study, we investigated and compared the intracellular calcium ([Ca2+]i) responses of osteocytic networks under steady and oscillatory fluid flows. An in vitro osteocytic network was built with MLO-Y4 osteo...

  19. Matrix-dependent adhesion mediates network responses to physiological stimulation of the osteocyte cell process

    OpenAIRE

    Wu, Danielle; Schaffler, Mitchell B.; Weinbaum, Sheldon; SPRAY, DAVID C.

    2013-01-01

    Osteocytes are bone cells that form cellular networks that sense mechanical loads distributed throughout the bone tissue. Interstitial fluid flow in the lacunar canalicular system produces focal strains at localized attachment sites around the osteocyte cell process. These regions of periodic attachment between the osteocyte cell membrane and its canalicular wall are sites where pN-level fluid-flow induced forces are generated in vivo. In this study, we show that focally applied forces of thi...

  20. Stroke and sleep-disordered breathing: A relationship under construction.

    Science.gov (United States)

    Parra, Olga; Arboix, Adrià

    2016-02-16

    The association between sleep-disordered breathing (SDB) and cardiovascular risk has been the focus of attention in recent years. Sleep disorders are emerging risk factors for cardiovascular disease and have been related to the whole spectrum of stroke, including transient ischemic attack, ischemic cerebral infarction and intracerebral haemorrhage. It has been shown that lacunar stroke or lacunar infarctions affecting the internal capsule or the protuberance are associated with a higher frequency of SDB. Acute stroke patients with associated SDB have a worse prognosis and a higher mortality as compared to patients with first-ever stroke without SDB. Preliminary studies provide evidence of the usefulness of treatment with continuous positive airway pressure when SDB is present in stroke patients. PMID:26881189

  1. Evaluation of geometric features as biomarkers of diabetic retinopathy for characterizing the retinal vascular changes during the progression of diabetes.

    Science.gov (United States)

    Leontidis, Georgios; Al-Diri, Bashir; Wigdahl, Jeffrey; Hunter, Andrew

    2015-01-01

    Diabetic retinopathy (DR) has been widely studied and characterized. However, until now, it is unclear how different features, extracted from the retinal vasculature, can be associated with the progression of diabetes and therefore become biomarkers of DR. In this study, a comprehensive analysis is presented, in which four groups were created, using eighty fundus images from twenty patients, who have progressed to DR and they had no history of any other diseases (e.g. hypertension or glaucoma). The significance of the following features was evaluated: widths, angles, branching coefficient (BC), angle-to-BC ratio, standard deviations, means and medians of widths and angles, fractal dimension (FD), lacunarity and FD-to-lacunarity ratio, using a mixed model analysis of variance (ANOVA) design. All the features were measured from the same junctions of each patient, using an automated tool. The discriminative power of these features was evaluated, using decision trees and random forests classifiers. Cross validation and out-of-bag error were used to evaluate the classifiers' performance, calculating the area under the ROC curve (AUC) and the classification error. Widths, FD and FD-to-Lacunarity ratio were found to differ significantly. Random forests had a superior performance of 0.768 and 0.737 in the AUC for the two cases of classification, namely three-years-pre-DR/post-DR and two-years-pre-DR/post-DR respectively.

  2. Relationships between personality traits, medial temporal lobe atrophy and white matter lesion in subjects suffering from mild cognitive impairment

    Directory of Open Access Journals (Sweden)

    Emmanuelle eDuron

    2014-07-01

    Full Text Available Mild Cognitive Impairment (MCI is a heterogeneous cognitive status that can be a prodromal stage of Alzheimer‘s disease (AD. It is particularly relevant to focus on prodromal stages of AD such as MCI, because pathophysiological abnormalities of AD start years before the dementia stage. Medial temporal lobe atrophy (MTL resulting from AD lesions and cerebrovascular lesions (i.e. white matter lesions (WML, lacunar strokes and strokes are often revealed concurrently on Magnetic Resonance Imaging (MRI in MCI subjects. Personality changes have been reported to be associated with MCI status and early AD. More specifically, an increase in neuroticism and a decrease in conscientiousness have been reported, suggesting that higher and lower scores, respectively in neuroticism and conscientiousness are associated with an increased risk of developing the disease. However, personality changes have not been studied concomitantly with pathological structural brain alterations detected on MRI in patients suffering from MCI. Therefore, the objective of the present study was to assess the relationship between MTL atrophy, WML, lacunar strokes and personality traits in such patients. The severity of WML was strongly associated with lower levels of conscientiousness and higher levels of neuroticism. Conversely, no association was detected between personality traits and the presence of lacunar strokes or MTL atrophy. Altogether, these results strongly suggest that personality changes occurring in a MCI population, at high risk of AD, are associated with WML, which can induce executive dysfunctions, rather than with MTL atrophy.

  3. Cerebral blood flow single-photon emission tomography with 123I-IMP in vascular dementia

    International Nuclear Information System (INIS)

    Cerebral blood flow differences between patients with vascular dementia, patients with multiple lacunar infarction without cognitive dysfunction, and age-matched controls were examined. Thirty four patients with vascular dementia (VD) were selected from consecutive referrals to the Memory Clinic at Narita Memorial Hospital. All the patients had routine assessment including history, physical and neurological examinations, neuropsychological assessment, blood tests, EEG, head MRI, and single photon emission computed tomography (SPECT). All of them fulfilled the NINDS-AIREN diagnostic criteria for vascular dementia. Thirty nine patients with multiple lacunar infarction without cognitive dysfunction and 110 age-matched controls were included in this study. Mean cerebral blood flow (mCBF) and regional cerebral blood flow (rCBF) were measured using N-isopropyl-P-123I-iodoamphetamine (123I-IMP) and SPECT imager. The mCBF in VD was 27.6±5.3 ml/100 g/min, while those in the control group and multiple lacunar infarction without cognitive dysfunction were 36.6±6.1 ml/100 g/min and 32.5±5.5 ml/100 g/min, respectively. The patients with VD demonstrated significantly reduced mCBF and rCBF in twenty regions including both cerebellar hemispheres as compared with those of the control group. Although there was no significant rCBF differences in bilateral inferior occipital regions and the right cerebellar hemisphere between patients with VD and multiple lacunar infarction without cognitive dysfunction, we could find significant lower rCBF in the remaining brain areas. In spite of the severity of VD, the diffuse decrease of cerebral blood flow was recognized in all patients with VD. (author)

  4. 手掌侧单孔入路微创治疗腕管综合征的解剖学研究%Anatomic study of the volar single-aperture approach of endoscopic carpal tunnel release

    Institute of Scientific and Technical Information of China (English)

    魏瑞鸿; 庄永青; 叶凤清; 姜浩力; 熊洪涛; 方锡池; 张轩

    2015-01-01

    Objective To report the palmar approach and surgical method for the view to provide anatomical data for the volar single-aperture approach of endoscopic carpal tunnel release(ECTR). Methods 16 specimens of fresh adult upper limb were used to observe and measure the anatomical structures in the carpal tunnel and palm. 6 specimens of fresh adult upper limb were used randomly to simulate the operation that divided the flexor retinaculum and released the median nerve of ECTR by one-point technique in palm. Results The best entrance point in palm of ECTR: Draw a parallel line along the thumb in the maximal abduction position to the ulnar side, and draw a axis between the middle finger and the ring finger;Mark the intersection of the lines, and then take an incision in the ulnar aspect about 1cm away from the intersection. Surgical plane was the lacunar space between the superficial fascia and palmar aponeursis. Conclusion Our study confirms that ECTR by one-point technique in palm is safe and feasible. It’s practical for surgeons to adopt the surgical approach of ECTR and avoid damage during severance offlexor retinaculum and relief of the median nerve under endoscope.%目的:报道手掌侧单孔入路微创治疗腕管综合征的解剖入路及手术方法,为手掌侧入路微创治疗腕管综合征手术提供解剖学基础。方法选取16例新鲜成人上肢标本,解剖观测腕管及手掌的相关解剖结构。选取6例新鲜成人上肢标本进行模拟手术,镜视下切开屈肌支持带并进行神经外膜松解。结果手术入路点为拇指呈最大外展位,沿掌指关节尺侧取一平行线,与中、环指间的长轴线交叉点处向尺侧1cm处,操作层面为浅筋膜层与掌腱膜间的腔隙。结论手掌侧单孔入路微创治疗腕管综合征是安全可行的,在镜视下可彻底切开屈肌支持带并进行神经外膜松解,有利于术者进行操作及减轻术中损伤。

  5. Pulmonary studies

    International Nuclear Information System (INIS)

    Radionuclide studies of the lung are described, as regards perfusion studies, ventilation studies and physiological considerations. The four principal applications for radionuclide studies of the lungs are outlined and the uses of these discussed in relation to particular entities including pulmonary embolic disease, congestive heart failure, asthma, acute, nonasthmatic, bronchial obstruction, chronic pulmonary disease and cancer. (Auth./C.F.)

  6. Feasibility of image registration and intensity-modulated radiotherapy planning with hyperpolarized helium-3 magnetic resonance imaging for non-small-cell lung cancer

    OpenAIRE

    Ireland, Rob H.; Bragg, Chris M; McJury, Mark; Woodhouse, Neil; Fichele, Stan; van Beek, Edwin J. R.; Wild, Jim M.; Hatton, Matthew Q.

    2007-01-01

    PURPOSE: To demonstrate the feasibility of registering hyperpolarized helium-3 magnetic resonance images ((3)He-MRI) to X-ray computed tomography (CT) for functionally weighted intensity-modulated radiotherapy (IMRT) planning.METHODS AND MATERIALS: Six patients with non-small-cell lung cancer underwent (3)He ventilation MRI, which was fused with radiotherapy planning CT using rigid registration. Registration accuracy was assessed using an overlap coefficient, calculated as the proportion of t...

  7. Cystometric study

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003904.htm Cystometric study To use the sharing features on this page, please enable JavaScript. Cystometric study measures the amount of fluid in the bladder ...

  8. 腔隙性脑梗死患者脑微出血与循环内皮微粒的相关性研究%Correlation between cerebral microbleeds and circulating endothelial microparticles in lacunar stroke patients

    Institute of Scientific and Technical Information of China (English)

    孔德燕

    2015-01-01

    目的 探讨腔隙性脑梗死患者脑微出血(CMB)与血浆内皮微粒(EMP)的关系.方法 选择首次发病3个月后的腔隙性脑梗死患者84例,根据磁敏感检测结果分为CMB组33例和无CMB组51例,收集2组患者的临床基线资料,并通过流式细胞仪检测其血浆CD31+/CD42-EMP水平.结果 CMB组EMP水平明显高于无CMB组[(451.93±94.46)×106/Lvs (310.93±55.47)×106/L,P=0.000].CMB严重程度与EMP呈正相关(r=0.817,P=0.000).二分类logistic回归分析显示,在控制了年龄、高血压、纤维蛋白原等混杂因素影响后,EMP升高仍是影响CMB发病的危险因素.结论血浆EMP升高是影响CMB发病的独立危险因素,EMP检测可作为临床预测脑梗死患者是否合并CMB的指标.

  9. Analysis on the correlation of cerebral microbleeds and post-stroke depression in lacunar stroke%脑微出血与腔隙性脑梗死患者卒中后抑郁的相关性分析

    Institute of Scientific and Technical Information of China (English)

    牛晓波; 缑元冲; 郭旭亮

    2015-01-01

    目的 探讨脑微出血(CMB)与腔隙性脑梗死(LI)患者卒中后抑郁的相关性.方法 选择腔隙性脑梗死患者216例,进行老年抑郁量表(GDS)评测,≥5分为存在抑郁,分为抑郁组和无抑郁组.记录两组CMB总数量及脑叶CMB、深部CMB、幕下CMB及左右半球CMB数量,分析两组CMB数量与部位、人口学资料、临床资料及影像学资料的关系.结果 两组在脑叶CMB及左半球CMB、女性、美国国立卫生研究院卒中量表(NIHSS)评分、脑白质病变(WML)、深部LI及左半球LI等方面比较差异有统计学意义(P<0.05).多因素分析提示脑叶CMB是卒中后抑郁(PSD)的独立危险因素(OR=5.843,P=0.040).结论 脑叶CMB及左半球CMB为PSD危险因素,其他危险因素包括女性、较严重的神经功能缺损、脑白质病变、LI特别是深部及左半球LI.

  10. Análisis comparativo de la leucoaraiosis en la enfermedad de Alzheimer, enfermedad de Binswanger y los infartos lacunares. Estudio por resonancia magnética convencional y espectroscópica

    OpenAIRE

    Valencia Calderón, Carlos Justo

    2002-01-01

    El avance en los sistemas sanitarios, en los conocimientos médicos y lasmejoras en la calidad de vida, han contribuido a que la expectativa de vida delas personas en los países desarrollados pueda superar los 80 años. Esto hapermitido observar el aumento de la frecuencia de enfermedades comunes enla tercera edad, de las cuales, una de las más relevantes es la demencia.Las dos etiologías más frecuentes de la demencia son la degenerativa, con laenfermedad de Alzheimer (EA) como causa principal...

  11. Análisis comparativo de la leucoaraiosis en la enfermedad de Alzheimer, la enfermedad de Binswanger y los infartos lacunares. Estudio por resonancia magnética convencional y espectroscópica

    OpenAIRE

    Valencia Calderón, Carlos Justo

    2002-01-01

    Descripció del recurs: 5 novembre 2002 Consultable des del TDX Títol obtingut de la portada digitalitzada El avance en los sistemas sanitarios, en los conocimientos médicos y lasmejoras en la calidad de vida, han contribuido a que la expectativa de vida delas personas en los países desarrollados pueda superar los 80 años. Esto hapermitido observar el aumento de la frecuencia de enfermedades comunes enla tercera edad, de las cuales, una de las más relevantes es la demencia.Las dos eti...

  12. Correlation Between Brain Lacunar Infarction And Insulin - Resistance In elderly%老年人脑腔隙梗死与胰岛素抵抗关系的临床研究

    Institute of Scientific and Technical Information of China (English)

    余玲玲; 陈治卿; 陈健; 周乃珍; 卓越; 李永忠; 梁立新; 林伯庚; 林纯毅

    2003-01-01

    目的探讨老年人脑腔隙梗死(腔梗)与胰岛素抵抗(IR)的关系.方法对354例受试者行空腹血糖(FPG)、甘油三脂(THG)、总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)检测.采用放免法测定空腹胰岛素(FIN).评估机体胰岛素抵抗(HOMA-IR),并计算其体重指数(BMI).将腔梗组按无、有高血压及高TG/低HDL分为Ⅰ、Ⅱ两组.结果腔梗组与健康对照组比较TG,TC、LDL、FPG、FIN、HOMA-IR有非常显著差异(P<0.01).在校正年龄、性别、BMI后老年人腔梗仍有显著的IR,且不受高血压和高TG的影响.结论老年人腔梗较健康老人有明显的IR.高TG、高LDL、IR是影响老年人腔梗的可能是独立的危险因素,老年人腔梗与IR关系密切,呈正相关.

  13. Case Studies

    International Nuclear Information System (INIS)

    Proven options available to Sri Lanka for large scale electricity generation in the future are coal-fired thermal, oil-fired thermal and Nuclear. Four case studies for groups participated are indicated. Case study for group 1 is comparison of the three options by taking into consideration the capital and recurrent expenditure involved. Environmental effects of the three options are also given. Case study for group 2 is economic comparison of three renewable energy based power generation system. Case study for group 3 is based on energy conservation, efficiency, improvement and demand management. Assuming that a continuous saving of 20 MW of demand from 1996 onwards is effective two projects are suggested to achieve this result. Case study for group 4 is a feasibility study for hydro power development of the Kukule Ganga (river) in Sri Lanka. Participants are required to evaluate one of the three optional development concepts which are technically feasible

  14. Studying Zooarchaeology

    Science.gov (United States)

    Moore, Molly; Wolf, Deborah; Butler, Virginia L.

    2012-01-01

    Children often associate the study of bones with dinosaurs or crime scenes. This unit introduces students to "zooarchaeology," the study of animal remains from archaeological sites. Students in grades 3-5 engage in hands-on activities examining bones, shells, and other "hard parts" of animals. They use their observations as a starting point for…

  15. Study of nanosensor systems for hypertension associated cerebrovascular and cardiovascular disorders

    Science.gov (United States)

    Ramasamy, Mouli; Varadan, Vijay K.

    2015-04-01

    Hypertension and hypertension associated cerebrovascular and cardiovascular diseases are on a rise. At-least 970 million people in the world and Seventy percent of the American adults are affected by high blood pressure, also known as hypertension. Even though blood pressure monitoring systems are readily available, the number of people being affected has been increasing. Most of the blood pressure monitoring systems require cumbersome approaches. Even the noninvasive techniques have not lowered the number of people affected nor did at-least increase the user base of these systems. Uncontrolled or untreated hypertension may lead to various cerebrovascular disorders including stroke, hypertensive crisis, lacunar infarcts intracerebral damage, microaneurysm, and cardiovascular disorders including heart failure, myocardial infraction, and ischemic heart disease. Hypertension is rated as the one of the most important causes of premature death in spite of the technical advances in biomedical technology. This paper briefs a review of the widely adopted blood pressure monitoring methods, research techniques, and finally, proposes a concept of implementing nanosensors and wireless communication for real time non-invasive blood pressure monitoring.

  16. Initial Study

    DEFF Research Database (Denmark)

    Torp, Kristian

    2009-01-01

    Congestion is a major problem in most cities and the problem is growing (Quiroga, 2000) (Faghri & Hamad, 2002). When the congestion level is increased the drivers notice this as delays in the traffic (Taylor, Woolley, & Zito, 2000), i.e., the travel time for the individual driver is simply...... increased. In the initial study presented here, the time it takes to pass an intersection is studied in details. Two major signal-controlled four-way intersections in the center of the city Aalborg are studied in details to estimate the congestion levels in these intersections, based on the time it takes...

  17. Floodplain Study

    Data.gov (United States)

    Montgomery County of Maryland — The purpose of a floodplain study is to establish the 100-year floodplain limits within or near a development in order to preserve the natural resources within the...

  18. Actuarial Studies

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Office of the Actuary in the Centers for Medicare and Medicaid Services (CMS) from time to time conducts studies on various aspects of the Medicare and Medicaid...

  19. Feasibility study

    International Nuclear Information System (INIS)

    The feasibility study itself examines the technical, economic and financial implications of a nuclear power station in depth so as to make sure that nuclear power is the right course to take. This means that it is quite an expensive operation and it is to avoid wasting this money that a pre-feasibility study is carried out. This preliminary study should eliminate cases where the electrical system cannot absorb the capacity of a nuclear station of commercial size, where other sources of power such as hydro-electricity, gas or cheap coal would make nuclear obviously uneconomic or where no suitable sites exist. If this first rather simple survey shows that nuclear power is a credible solution to a utilities need for electricity or heat production plant, then the next stage is a full feasibility study. (orig./TK)

  20. Studying Sideways

    DEFF Research Database (Denmark)

    Plesner, Ursula

    2011-01-01

    inequalities in relation to the people we study. This article argues that not all types of social scientific research interviews benefit from an à priori problematization of power and control, ethics and equality, or emancipation. From a constructivist perspective, the article seeks to displace...... the methodological concern with power related to the ideas of studying up or down and introduce another set of concerns in relation to producing good empirical material when we “study sideways.” The argument is based on analyses of interview situations from a concrete research project, where researcher...... and researched share professional background to some degree, where negotiations replace a researcher-imposed dialogue, and where the circulation of shared or common concepts messes up an orderly division between researchers’ vocabulary and interviewees’ vocabularies. It is proposed that when we study sideways...

  1. Nonlinear analysis of drainage systems to examine surface deformation: an example from Potwar Plateau (Northern Pakistan

    Directory of Open Access Journals (Sweden)

    F. Shahzad

    2010-03-01

    Full Text Available We devise a procedure in order to characterize the relative vulnerability of the Earth's surface to tectonic deformation using the geometrical characteristics of drainage systems. The present study focuses on the nonlinear analysis of drainage networks extracted from Digital Elevation Models in order to localize areas strongly influenced by tectonics. We test this approach on the Potwar Plateau in northern Pakistan. This area is regularly affected by damaging earthquakes. Conventional studies cannot pinpoint the zones at risk, as the whole region is characterized by a sparse and diffuse seismicity. Our approach is based on the fact that rivers tend to linearize under tectonic forcing. Thus, the low fractal dimensions of the Swan, Indus and Jehlum Rivers are attributed to neotectonic activity. A detailed textural analysis is carried out to investigate the linearization, heterogeneity and connectivity of the drainage patterns. These textural aspects are quantified using the fractal dimension, as well as lacunarity and succolarity analysis. These three methods are complimentary in nature, i.e. objects with similar fractal dimensions can be distinguished further with lacunarity and/or succolarity analysis. We generate maps of fractal dimensions, lacunarity and succolarity values using a sliding window of 2.5 arc minutes by 2.5 arc minutes (2.5'×2.5'. These maps are then interpreted in terms of land surface vulnerability to tectonics. This approach allowed us to localize several zones where the drainage system is highly structurally controlled on the Potwar Plateau. The region located between Muree and Muzaffarabad is found to be prone to destructive events whereas the area westward from the Indus seems relatively unaffected. We conclude that a nonlinear analysis of the drainage system is an efficient additional tool to locate areas likely to be affected by massive destructing events affecting the Earth's surface and therefore threaten human

  2. Writing Study and Grammar Study

    Institute of Scientific and Technical Information of China (English)

    马青

    2013-01-01

    This study is undertaken to describe,classify and analyze the problems in Chinese college students’ writing of CET-4 through contrastive analysis,statistical analysis and error analysis.The main problems appearing in CET-4 writing are the wrong usage of words,sentence structures and the lack of coherence.Meanwhile it proves grammar study plays an important and basic role in CET-4 writing.

  3. Reaction of cobalt molybdophosphate with alcoholic solutions of tetraethoxysilane and oxozirconium(IV) chloride

    International Nuclear Information System (INIS)

    Interaction of cobalt molybdophosphate with alcohol solutions of tetraethoxysilane and oxozirconium chloride was studied using the methods of IR spectroscopy and thermal analysis with an aim of ascertaining the potentiality of the reagents application for production of thermochrome materials. It was ascertained that as a results of interaction between cobalt molybdophosphate and tetraethoxysilane solution the heteropolyanion [PMo12O40]3- was transformed into lacunar form [HxPMo11O39]7-x. The hydrolysis processes occurring in compositions with oxozirconium chloride does not permit stabilizing the structure of the heteropolycompound responsible for thermochrome transitions

  4. Security studies

    International Nuclear Information System (INIS)

    Full text: Security studies constitute one of the major tools for evaluating the provisions implemented at facilities to protect and control Nuclear Material against unauthorized removal. Operators use security studies to demonstrate that they are complying with objectives set by the Competent Authority to counter internal or external acts aimed at unauthorized removal of NM. The paper presents the context of security studies carried out in France. The philosophy of these studies is based on a postulated unauthorized removal of NM and the study of the behavior of the systems implemented to control and protect NM in a facility. The potential unauthorized removal of NM usually may take place in two stages. The first stage involves the sequence leading to handling of the NM. It occurs inside the physical barriers of a facility and may include action involving the documents corresponding to Material Control and Accounting systems. At this stage it is possible to limit the risk of unauthorized removal of NM by means of detection capabilities of the MC and A systems. The second stage is more specific to theft and involves removing the NM out of the physical barriers of a facility in which they are being held, notably by affecting the Physical Protection System. Operators have to study, from a quantity and time lapse point of view, the ability of the installed systems to detect unauthorized removal, as well as the possibility of tampering with the systems to mask unlawful operations. Operators have also to analyze the sequences during which NM are accessed, removed from their containment and further removed from the facility in which they are stored. At each stage in the process, the probability of detection and the time taken to carry out the above actions have to be estimated. Of course, these two types of studies complement each other. Security studies have begun, in France, for more than fifteen years. Up to now more than fifty security studies are available in the

  5. Fractal analysis of the structural complexity of the connective tissue in human carotid bodies

    Science.gov (United States)

    Guidolin, Diego; Porzionato, Andrea; Tortorella, Cinzia; Macchi, Veronica; De Caro, Raffaele

    2014-01-01

    The carotid body (CB) may undergo different structural changes during perinatal development, aging, or in response to environmental stimuli. In the previous literature, morphometric approaches to evaluate these changes have considered quantitative first order parameters, such as volumes or densities, while changes in spatial disposition and/or complexity of structural components have not yet been considered. In the present study, different strategies for addressing morphological complexity of CB, apart from the overall amount of each tissue component, were evaluated and compared. In particular, we considered the spatial distribution of connective tissue in the carotid bodies of young control subjects, young opiate-related deaths and aged subjects, through analysis of dispersion (Morisita's index), gray level co-occurrence matrix (entropy, angular second moment, variance, correlation), and fractal analysis (fractal dimension, lacunarity). Opiate-related deaths and aged subjects showed a comparable increase in connective tissue with respect to young controls. However, the Morisita's index (p < 0.05), angular second moment (p < 0.05), fractal dimension (p < 0.01), and lacunarity (p < 0.01) permitted to identify significant differences in the disposition of the connective tissue between these two series. A receiver operating characteristic (ROC) curve was also calculated to evaluate the efficiency of each parameter. The fractal dimension and lacunarity, with areas under the ROC curve of 0.9651 (excellent accuracy) and 0.8835 (good accuracy), respectively, showed the highest discriminatory power. They evidenced higher level of structural complexity in the carotid bodies of opiate-related deaths than old controls, due to more complex branching of intralobular connective tissue. Further analyses will have to consider the suitability of these approaches to address other morphological features of the CB, such as different cell populations, vascularization, and innervation

  6. Study protocol

    DEFF Research Database (Denmark)

    Thorsteinsson, Troels; Helms, Anne Sofie; Adamsen, Lis;

    2013-01-01

    of first-line cancer therapy. Secondary endpoints are quality of life measured by validated questionnaires and interviews, and physical performance. RESPECT includes a multimodal intervention program, including ambassador-facilitated educational, physical, and social interventions. The educational......Background During cancer treatment children have reduced contact with their social network of friends, and have limited participation in education, sports, and leisure activities. During and following cancer treatment, children describe school related problems, reduced physical fitness......, and problems related to interaction with peers. Methods/design The RESPECT study is a nationwide population-based prospective, controlled, mixed-methods intervention study looking at children aged 6-18 years newly diagnosed with cancer in eastern Denmark (n = 120) and a matched control group in western Denmark...

  7. Treatability studies

    DEFF Research Database (Denmark)

    Bennedsen, Lars Rønn; Studds, Phil

    developed a mobile test unit including equipment for both standard and more advanced oxidation test directly on the site. The remediation techniques included are electrochemical oxidation, photochemical/photocatalytic oxidation, ozone, Fenton’s, permanganate, and persulfate among others. A versatile...... construction of the test unit makes it possible to combine different techniques in order to obtain more aggressive and effective remediation technologies, e.g. UV/ozone or electrochemical/H2O2. Actual case study data is presented to illustrate the benefits of in situ treatability tests prior to full scale......The fundamental information that a well-designed treatability study can provide is essential to the success of all remediation systems. Over the past years several new techniques for in situ and on site remediation of contaminated soil and groundwater have been used with varying degrees of success...

  8. Invisibility Studies

    DEFF Research Database (Denmark)

    Invisibility Studies explores current changes in the relationship between what we consider visible and what invisible in different areas of contemporary culture. Contributions trace how these changes make their marks on various cultural fields and investigate the cultural significance...... of these developments, such as transparency and privacy in urban architecture and the silent invasion of surveillance technologies into everyday life. The book contends that when it comes to the changing relationship of the visible and the invisible, the connection between seeing and not being seen is an exchange...... conditioned by physical and social settings that create certain possibilities for visibility and visuality, yet exclude others. The richness and complexity of this cultural framework means that no single discipline or interdisciplinary approach could capture it single-handedly. Invisibility Studies begins...

  9. Studying Adolescence

    OpenAIRE

    Richter, Linda M.

    2006-01-01

    Young people in their teens constitute the largest age group in the world, in a special stage recognized across the globe as the link in the life cycle between childhood and adulthood. Longitudinal studies in both developed and developing countries and better measurements of adolescent behavior are producing new insights. The physical and psychosocial changes that occur during puberty make manifest generational and early-childhood risks to development, in the form of individual differences in...

  10. The Relationship between C-Reactive Protein Level and Discharge Outcome in Patients with Acute Ischemic Stroke

    Science.gov (United States)

    Geng, He-Hong; Wang, Xin-Wang; Fu, Rong-Li; Jing, Meng-Juan; Huang, Ling-Ling; Zhang, Qing; Wang, Xiao-Xiao; Wang, Pei-Xi

    2016-01-01

    Previous studies showed that C-reactive protein (CRP), an inflammatory marker, was associated with stroke severity and long-term outcome. However, the relationship between the acute-phase CRP level and discharge outcome has received little attention. We prospectively studied 301 patients with acute ischemic stroke (over a period of two weeks) from two hospital stroke wards and one rehabilitation department in Henan, China. Patients’ demographic and clinical data were collected and evaluated at admission. Poor discharge outcome was assessed in patients at discharge using the Modified Rankin Scale (MRS > 2). Multivariate logistic regression analysis was performed to determine the risk factors of poor discharge outcome after adjusting for potential confounders. Poor discharge outcome was observed in 78 patients (25.9%). Univariate analyses showed that factors significantly influencing poor discharge outcome were age, residence, recurrent acute ischemic stroke, coronary heart disease, the National Institutes of Health Stroke Scale (NIHSS) score at admission, non-lacunar stroke, time from onset of stroke to admission, CRP, TBIL (total bilirubin), direct bilirubin (DBIL), ALB (albumin), FIB (fibrinogen) and D-dimer (p < 0.05). After adjusting for age, residence, recurrent ischemic stroke, coronary heart disease, NIHSS score at admission, lacunar stroke, time from onset of stroke to admission, CRP, TBIL, DBIL, ALB, FIB and D-dimer, multivariate logistic regression analyses revealed that poor outcome at discharge was associated with recurrent acute ischemic stroke (OR, 2.115; 95% CI, 1.094–4.087), non-lacunar stroke (OR, 2.943; 95% CI, 1.436–6.032), DBIL (OR, 1.795; 95% CI, 1.311–2.458), and CRP (OR, 4.890; 95% CI, 3.063–7.808). In conclusion, the CRP level measured at admission was found to be an independent predictor of poor outcome at discharge. Recurrent acute ischemic stroke, non-lacunar stroke and DBIL were also significantly associated with discharge

  11. Study protocol

    DEFF Research Database (Denmark)

    Madsen, Helle Østergaard; Dam, Ole Henrik; Hageman, Ida

    2012-01-01

    yields a Global Seasonal Score and a prevalence of SAD. Outcomes from the two groups will be compared. Moreover, outcomes from subgroups of the visually impaired population will be compared. ETHICS AND DISSEMINATION: The study is approved by the Danish Data Protection Agency. Results will be published...... in persons with severe visual impairments or blindness and to compare the results to a control group without visual impairments. Moreover, the authors wish to investigate whether SAD is correlated to the degree of impairment or to the diagnosis. METHODS AND ANALYSIS: 2781 persons with visual impairments...

  12. SOCIOLOGICAL STUDIES

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    PAPER Post-Sociology: Exploration and Reflection Xie Lizhong Abstract: "Post-Sociology" refers to a new perspective which is different from tradi- tional perspectives of social studies. "Post-Social History" and "Pluralistic Discourse Analysis" could be seen as its two specific examples. "Discourse Constructivism" and "Pluralism" are the two core concepts of "Post-Sociology". That encouraging people to realize that all "social reality" including our experiences, thoughts and speech are just a "discoursive reality" constructed by social actors under the guidance and constraints of certain discourse system, is the major significance of "PostSociology". Some critics on "Post-Sociology" are misunderstandings, while others couldn't stand to strict analysis.

  13. Conceptual study

    International Nuclear Information System (INIS)

    This appendix is a compendium of topical reports prepared for the Hanford Nuclear Energy Center: Status Report: Conceptual Fuel Cycle Studies for the Hanford Nuclear Energy Center; Selection of Heat Disposal Methods for a Hanford Nuclear Energy Center; Station Service Power Supply for a Hanford Nuclear Energy Center (HNEC); Impact of a Hanford Nuclear Energy Center on Ground Level Fog and Humidity; A Review of Potential Technology for the Seismic Characterization of Nuclear Energy Centers; Reliability of Generation at a Hanford Nuclear Energy Center (HNEC); Meteorological Evaluation of Multiple Reactor Contamination Probabilities for a Hanford Nuclear Energy Center; Electric Power Transmission for a Hanford Nuclear Energy Center (HNEC); The Impact of a Hanford Nuclear Energy Center on Cloudiness and Insolation; and A Licensing Review for an HNEC

  14. Conceptual study

    Energy Technology Data Exchange (ETDEWEB)

    Harty, H.

    1978-09-01

    This appendix is a compendium of topical reports prepared for the Hanford Nuclear Energy Center: Status Report: Conceptual Fuel Cycle Studies for the Hanford Nuclear Energy Center; Selection of Heat Disposal Methods for a Hanford Nuclear Energy Center; Station Service Power Supply for a Hanford Nuclear Energy Center (HNEC); Impact of a Hanford Nuclear Energy Center on Ground Level Fog and Humidity; A Review of Potential Technology for the Seismic Characterization of Nuclear Energy Centers; Reliability of Generation at a Hanford Nuclear Energy Center (HNEC); Meteorological Evaluation of Multiple Reactor Contamination Probabilities for a Hanford Nuclear Energy Center; Electric Power Transmission for a Hanford Nuclear Energy Center (HNEC); The Impact of a Hanford Nuclear Energy Center on Cloudiness and Insolation; and A Licensing Review for an HNEC.

  15. Systems studies

    International Nuclear Information System (INIS)

    The Systems Studies Activity had two objectives: (1) to investigate nontechnical barriers to the deployment of biomass production and supply systems and (2) to enhance and extend existing systems models of bioenergy supply and use. For the first objective, the Activity focused on existing bioenergy markets. Four projects were undertaken: a comparative analysis of bioenergy in Sweden and Austria; a one-day workshop on nontechnical barriers jointly supported by the Production Systems Activity, the development and testing of a framework for analyzing barriers and drivers to bioenergy markets; and surveys of wood pellet users in Sweden, Austria and the U.S.A. For the second objective, two projects were undertaken. First, the Activity worked with the Integrated Bioenergy Systems (IBS) Activity of IEA Bioenergy Task XIII to enhance the BioEnergy Assessment Model (BEAM). This model is documented in the final report of the IBS Activity. The Systems Studies Activity contributed to enhancing the feedstock portion of the model by developing a coherent set of willow, poplar, and switchgrass production modules relevant to both the U.S.A. and the U.K. The Activity also developed a pretreatment module for switchgrass. Second, the Activity sponsored a three-day workshop on modelling bioenergy systems with the objectives of providing an overview of the types of models used to evaluate bioenergy and promoting communication among bioenergy modelers. There were nine guest speakers addressing different types of models used to evaluate different aspects of bioenergy, ranging from techno-economic models based on the ASPEN software to linear programming models to develop feedstock supply curves for the U.S.A. The papers from this workshop have been submitted to Biomass and Bioenergy and are under editorial review 8 refs, 10 tabs

  16. Systems Studies

    Energy Technology Data Exchange (ETDEWEB)

    Graham, R.L.

    1998-03-17

    The Systems Studies Activity had two objectives: (1) to investigate nontechnical barriers to the deployment of biomass production and supply systems and (2) to enhance and extend existing systems models of bioenergy supply and use. For the first objective, the Activity focused on existing bioenergy markets. Four projects were undertaken: a comparative analysis of bioenergy in Sweden and Austria; a one-day workshop on nontechnical barriers jointly supported by the Production Systems Activity; the development and testing of a framework for analyzing barriers and drivers to bioenergy markets; and surveys of wood pellet users in Sweden, Austria and the US. For the second objective, two projects were undertaken. First, the Activity worked with the Integrated BioEnergy Systems (TBS) Activity of TEA Bioenergy Task XIII to enhance the BioEnergy Assessment Model (BEAM). This model is documented in the final report of the IBS Activity. The Systems Studies Activity contributed to enhancing the feedstock portion of the model by developing a coherent set of willow, poplar, and switchgrass production modules relevant to both the US and the UK. The Activity also developed a pretreatment module for switchgrass. Second, the Activity sponsored a three-day workshop on modeling bioenergy systems with the objectives of providing an overview of the types of models used to evaluate bioenergy and promoting communication among bioenergy modelers. There were nine guest speakers addressing different types of models used to evaluate different aspects of bioenergy, ranging from technoeconomic models based on the ASPEN software to linear programming models to develop feedstock supply curves for the US. The papers from this workshop have been submitted to Biomass and Bioenergy and are under editorial review.

  17. A case of thalamic hemorrhage-induced diaschisis

    Institute of Scientific and Technical Information of China (English)

    Gang Yao; Yuhong Man; Xijing Mao; Tingmin Yu

    2011-01-01

    Diaschisis refers to a disturbance (inhibition or facilitation) of function in an area remote from the site of a primary brain lesion. Previous studies have confirmed that regional cerebral blood flow and metabolism are noticeably decreased in an infarct region. Transient excessive perfusion appears in the ischemic penumbra, and diaschisis occurs in an area remote from the lesion site, showing decreased regional cerebral blood flow and metabolism. Mirror diaschisis refers to a decrease in oxygen metabolism and blood flow in the "mirror image area" to the infarct regions in the contralateral hemisphere. In this study, a patient with right thalamic hemorrhage was affected with right arm and leg numbness. At 4 months before onset, magnetic resonance imaging of the head demonstrated lacunar infarcts in the left thalamus; therefore the right arm and leg numbness was not associated with lacunar infarcts in the left thalamus. At 8 days following onset, magnetic resonance imaging reexamination did not reveal the focus that could induce right arm and leg numbness and weakness. Thus, it is suggested in this study that the onset of this disease can be explained by mirror diaschisis. That is, right thalamic hemorrhage leads to decreased blood flow and metabolic disturbance in the contralateral thalamus, resulting in right arm and leg numbness.

  18. Age-related reduction of chromatin fractal dimension in toluidine blue - stained hepatocytes.

    Science.gov (United States)

    Pantic, Igor; Petrovic, Danica; Paunovic, Jovana; Vucevic, Danijela; Radosavljevic, Tatjana; Pantic, Senka

    2016-07-01

    In this study, we proposed a hypothesis that chromatin of mouse hepatocytes exhibits age-related reduction of fractal dimension. This hypothesis was based on previously published works demonstrating that complexity of biological systems such as tissues, decreases during the process of physiological aging. Liver tissue was obtained from 24 male mice divided into 3 age groups: 10-days-old (young, juvenile), 210-days-old (adult) and 390-days-old. The tissue was stained using a modification of toluidine blue (nucleic acid - specific) staining method. A total of 480 chromatin structures (20 for each animal) were analyzed. For each structure, the values of fractal dimension, lacunarity, textural angular second moment and inverse difference moment were calculated using ImageJ software and its plugins. The results indicated the age-related reduction in fractal dimension and increase in lacunarity (p<0.01). Fractal dimension is a potentially good indicator of age associated changes in chromatin structure. To our knowledge, this is the first study to show that fractal complexity of hepatocyte chromatin decreases during the process of physiological aging. Fractal analysis as a method could be useful in detection of small age-related changes in chromatin distribution not otherwise visible with naked eye on conventional tissue micrographs. PMID:27412950

  19. Assessment of intra and extra cranial atherosclerosis in coronary artery disease. Advantage of MRI/MRA

    International Nuclear Information System (INIS)

    The incidence of arteriosclerosis has increased in recent years as the aging population has grown. We carried out the present study to investigate the association of internal carotid arteriosclerosis, sclerosis of intracranial main arteries, and cerebral arteriolosclerosis to coronary arteriosclerosis using MRI and MRA in a total of 133 consecutive patients (107 males and 26 females), who visited our hospital with a main complaint of chest pain. We also examined serum lipids and the presence or absence of hypertension and/or diabetes. Coronary arteriosclerosis underlying atherosclerotic lesions was correlated with internal carotid arteriosclerosis, serum cholesterol and low HDL cholesterol level. As characteristic findings of this study, lacunar infarction (LI), which is thought to represent cerebral arteriolosclerosis, was not only significantly correlated with age and hypertension, but increased also lacunar infarcts in number as the number of affected coronary branches increased. Examination of the cases of severe coronary artery disease with MRI/MRA was thought to be able to predict the occurrence of cerebrovascular disorder after CABG and to be useful for the selection of a therapeutic regimen, such as PTCA and MID-CABG. (author)

  20. Assessment of intra and extra cranial atherosclerosis in coronary artery disease. Advantage of MRI/MRA

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, Hirohide; Oda, Yoshinori; Hirai, Akio; Ibukiyama, Chiharu; Utsugi, Osamu [Tokyo Medical Coll. (Japan)

    1999-02-01

    The incidence of arteriosclerosis has increased in recent years as the aging population has grown. We carried out the present study to investigate the association of internal carotid arteriosclerosis, sclerosis of intracranial main arteries, and cerebral arteriolosclerosis to coronary arteriosclerosis using MRI and MRA in a total of 133 consecutive patients (107 males and 26 females), who visited our hospital with a main complaint of chest pain. We also examined serum lipids and the presence or absence of hypertension and/or diabetes. Coronary arteriosclerosis underlying atherosclerotic lesions was correlated with internal carotid arteriosclerosis, serum cholesterol and low HDL cholesterol level. As characteristic findings of this study, lacunar infarction (LI), which is thought to represent cerebral arteriolosclerosis, was not only significantly correlated with age and hypertension, but increased also lacunar infarcts in number as the number of affected coronary branches increased. Examination of the cases of severe coronary artery disease with MRI/MRA was thought to be able to predict the occurrence of cerebrovascular disorder after CABG and to be useful for the selection of a therapeutic regimen, such as PTCA and MID-CABG. (author)

  1. Asymptomatic ischemic cerebral lesions

    International Nuclear Information System (INIS)

    For the purpose of studying the incidence, pathomorphology and etiology of asymptomatic ischemic cerebral lesions, we carried out a brain MRI study on 65 patients with diabetes mellitus accompanied with hypertension who are thought to belong to a high risk group of ischemic cerebrovascular diseases. Excluding the abnormality of tendon reflex due to diabetic neuropathy, sixty percent of the total patients had some mild neurological signs and symptoms, most of them was discrepancy in tendon reflex. The percentage of the patients in whom MRI disclosed some abnormalities was as high as 70%, they were lacunar stroke, multiple lacunar state, cortical infarct, and patchy high signal lesions visible only in the T2 weighted image. Lacunes or these patchy high signal lesions (considered to be the dilatation of the perivascular space or true lacunes) tended to be found along the border zone or the terminal zone. These results indicate that asymptomatic patients in whom MRI discloses the abnormalities should be considered as candidates for the future onset of multi-infarct. (author)

  2. Study on the clinical usefulness of magnetic resonance imaging in cases of multiple cerebral infarction

    International Nuclear Information System (INIS)

    The clinical significance of MRI in thrombotic multiple cerebral infarction was examined in 9 patients having recent lacunar stroke. Recent infarct was identified on Gd-enhanced MRI in 4 patients. For patients multiple small infarction, Gd-enhanced MRI made it possible to differentiate recent from other lesions. To clarify the significance of periventricular high intensity lesion (PVH) on T2-weighted MRI, hemodynamic and neuropsychologic examinations were carried out in 41 patients with multiple cerebral infarction. All the patients had PVH, which was classified into three grades as follows: grade I (n=16) showing only a thin high intensity band along the body of lateral ventricles; grade 2 (n=15) showing a definite high intensity area around the lateral ventricles; grade 3 (n=10) showing diffuse thick and irregular foci around the whole ventricle. In these patients, rCBF was measured by 133Xe inhalation methods. Initial slope index was significantly higher in patients with grade 3 than those with grade I. Mini-mental state test score was significantly higher in patients with grade l than those with grade 2 and 3. Progression of PVH may be related with the reduction of the cerebral circulation and mental function in cases of multiple cerebral infarction. Ischemic and hemorrhagic lesions can be distinguished by MRI, because old intracerebral hemorrhage appear as hypointensity areas with or without hyperintensity area on T2w images. In 92 patients with multiple infarction, MRI was used to evaluate the incidence and distribution of coexisting old intracerebral hemorrhage. Old hemorrhage were found in 15 patients (16.3%). locating the site where hypertensive hemorrhage commonly occurred. High-field MRI is useful for assessing the coexistence of hemorrhage in hypertensive patients with multiple cerebral infarction. (N.K.)

  3. Study on the clinical usefulness of magnetic resonance imaging in cases of multiple cerebral infarction

    Energy Technology Data Exchange (ETDEWEB)

    Miyashita, Kotaro (Niigata Univ. (Japan). Brain Research Inst.)

    1991-09-01

    The clinical significance of MRI in thrombotic multiple cerebral infarction was examined in 9 patients having recent lacunar stroke. Recent infarct was identified on Gd-enhanced MRI in 4 patients. For patients multiple small infarction, Gd-enhanced MRI made it possible to differentiate recent from other lesions. To clarify the significance of periventricular high intensity lesion (PVH) on T2-weighted MRI, hemodynamic and neuropsychologic examinations were carried out in 41 patients with multiple cerebral infarction. All the patients had PVH, which was classified into three grades as follows: grade I (n=16) showing only a thin high intensity band along the body of lateral ventricles; grade 2 (n=15) showing a definite high intensity area around the lateral ventricles; grade 3 (n=10) showing diffuse thick and irregular foci around the whole ventricle. In these patients, rCBF was measured by {sup 133}Xe inhalation methods. Initial slope index was significantly higher in patients with grade 3 than those with grade I. Mini-mental state test score was significantly higher in patients with grade l than those with grade 2 and 3. Progression of PVH may be related with the reduction of the cerebral circulation and mental function in cases of multiple cerebral infarction. Ischemic and hemorrhagic lesions can be distinguished by MRI, because old intracerebral hemorrhage appear as hypointensity areas with or without hyperintensity area on T2w images. In 92 patients with multiple infarction, MRI was used to evaluate the incidence and distribution of coexisting old intracerebral hemorrhage. Old hemorrhage were found in 15 patients (16.3%). locating the site where hypertensive hemorrhage commonly occurred. High-field MRI is useful for assessing the coexistence of hemorrhage in hypertensive patients with multiple cerebral infarction. (N.K.).

  4. Clinicoradiological study on 59 patients with pure motor hemiparesis due to corona radiata infarcts

    International Nuclear Information System (INIS)

    To evaluate the clinicoradiological findings of patients with small infarction at the level of the corona radiata, such patients were divided into three groups: Group A (facio-lingual weakness), Group B (arm-dominant weakness) and Group C (leg-dominant weakness). The anteroposterior position and maximum diameter of the radiata infarcts were assessed by axial T2-weighted imaging. In total, 59 consecutive patients (42 men and 17 women) were selected. The frequency of radiata infarct is 9.4% among cerebral infarct patients. The male/female ratio was 1.3. The mean age (SD) was 68.9 (9.5) years. The number of patients was 23 in Group A, 19 in Group B and 17 in Group C. Group B patients needed aid in their daily life, when compared to Group A and Group C. The cerebrovascular risk profiles demonstrated hypertension in 43 patients (72.9%), diabetes mellitus in 15 (25.4%), current smoking in 22 (37.3%), dyslipidemia in 16 (27.1%) and arterial fibrillation in 11 (18.6%). The clinical subtypes revealed 48 patients with lacunar infarct and 11 with cardiogenic emboli. The somatotopical distribution of motor fibers of Groups A to C was arranged in antero-posterior order. There were 24 patients with right lesions and 35 with left lesions. The size of the left infarcts was significantly smaller than that of the right infarcts. The clinical outcome of patients with arm-dominant weakness was relatively poor as compared to that of patients with dysarthria or leg-dominant weakness. The neuroradiological data suggest that left radiata infarct is smaller and more frequent than right infarct. (author)

  5. An analysis of Methylenetetrahydrofolate reductase and Glutathione S-transferase omega-1 genes as modifiers of the cerebral response to ischemia

    Directory of Open Access Journals (Sweden)

    Sen Souvik

    2009-07-01

    Full Text Available Abstract Background Cerebral ischemia involves a series of reactions which ultimately influence the final volume of a brain infarction. We hypothesize that polymorphisms in genes encoding proteins involved in these reactions could act as modifiers of the cerebral response to ischemia and impact the resultant stroke volume. The final volume of a cerebral infarct is important as it correlates with the morbidity and mortality associated with non-lacunar ischemic strokes. Methods The proteins encoded by the methylenetetrahydrofolate reductase (MTHFR and glutathione S-transferase omega-1 (GSTO-1 genes are, through oxidative mechanisms, key participants in the cerebral response to ischemia. On the basis of these biological activities, they were selected as candidate genes for further investigation. We analyzed the C677T polymorphism in the MTHFR gene and the C419A polymorphism in the GSTO-1 gene in 128 patients with non-lacunar ischemic strokes. Results We found no significant association of either the MTHFR (p = 0.72 or GSTO-1 (p = 0.58 polymorphisms with cerebral infarct volume. Conclusion Our study shows no major gene effect of either the MTHFR or GSTO-1 genes as a modifier of ischemic stroke volume. However, given the relatively small sample size, a minor gene effect is not excluded by this investigation.

  6. Cerebral hemodynamic dysfunction in parkinsonian patients

    Directory of Open Access Journals (Sweden)

    Mirjana Vladetić

    2009-02-01

    Full Text Available Aim The purpose of this investigation was to determine the cerebral hemodynamics in patients withparkinsonism and the influence of hemodynamic dysfunction in developing the lacunar infarcts.Methods Fifty patients with the signs of parkinsonism were included in this study. The patients weredevided into two subgroups depending on whether they had vascular parkinsonism (VP (N-22 or idiopathicParkinson disease (N-28. The control group consisted of 30 patients who had ischemic stroke.The conventional transcranial dopler sonography was performed to evaluate the cerebral blood flow.To evaluate the cognitive impairment we performed the mini mental state examination to patients withparkinsonism.Results Patients with vascular parkinsonism have greater cognitive disturbances than patients withParkinson disease. In most of the parkinsonian patients the cerebral blood flow was decreased and themicroangiopathy was present.Conclusion In most patients with parkinsonism, the cerebral blood flow was decreased as a consequenceof microangiopathy. In our opinion, this led to lacunar infarction in VP patients, but can also bea risk factor for developing the same changes in patients with idiopathic Parkinson disease.

  7. Aortic stiffness is associated with cardiac function and cerebral small vessel disease in patients with type 1 diabetes mellitus: assessment by magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Elderen, Saskia G.C. van; Brandts, A.; Westenberg, J.J.M.; Grond, J. van der; Buchem, M.A. van; Kroft, L.J.M.; Roos, A. de [Leiden University Medical Center, Department of Radiology, Leiden (Netherlands); Tamsma, J.T.; Romijn, J.A.; Smit, J.W.A. [Leiden University Medical Center, Department of Endocrinology, Leiden (Netherlands)

    2010-05-15

    To evaluate, with the use of magnetic resonance imaging (MRI), whether aortic pulse wave velocity (PWV) is associated with cardiac left ventricular (LV) function and mass as well as with cerebral small vessel disease in patients with type 1 diabetes mellitus (DM). We included 86 consecutive type 1 DM patients (49 male, mean age 46.9 {+-} 11.7 years) in a prospective, cross-sectional study. Exclusion criteria included aortic/heart disease and general MRI contra-indications. MRI of the aorta, heart and brain was performed for assessment of aortic PWV, as a marker of aortic stiffness, systolic LV function and mass, as well as for the presence of cerebral white matter hyperintensities (WMHs), microbleeds and lacunar infarcts. Multivariate linear or logistic regression was performed to analyse the association between aortic PWV and outcome parameters, with covariates defined as age, gender, mean arterial pressure, heart rate, BMI, smoking, DM duration and hypertension. Mean aortic PWV was 7.1 {+-} 2.5 m/s. Aortic PWV was independently associated with LV ejection fraction (ss= -0.406, P = 0.006), LV stroke volume (ss=-0.407, P = 0.001), LV cardiac output (ss= -0.458, P = 0.001), and with cerebral WMHs (P < 0.05). There were no independent associations between aortic stiffness and LV mass, cerebral microbleeds or lacunar infarcts. Aortic stiffness is independently associated with systolic LV function and cerebral WMHs in patients with type 1 DM. (orig.)

  8. Aortic stiffness is associated with cardiac function and cerebral small vessel disease in patients with type 1 diabetes mellitus: assessment by magnetic resonance imaging

    International Nuclear Information System (INIS)

    To evaluate, with the use of magnetic resonance imaging (MRI), whether aortic pulse wave velocity (PWV) is associated with cardiac left ventricular (LV) function and mass as well as with cerebral small vessel disease in patients with type 1 diabetes mellitus (DM). We included 86 consecutive type 1 DM patients (49 male, mean age 46.9 ± 11.7 years) in a prospective, cross-sectional study. Exclusion criteria included aortic/heart disease and general MRI contra-indications. MRI of the aorta, heart and brain was performed for assessment of aortic PWV, as a marker of aortic stiffness, systolic LV function and mass, as well as for the presence of cerebral white matter hyperintensities (WMHs), microbleeds and lacunar infarcts. Multivariate linear or logistic regression was performed to analyse the association between aortic PWV and outcome parameters, with covariates defined as age, gender, mean arterial pressure, heart rate, BMI, smoking, DM duration and hypertension. Mean aortic PWV was 7.1 ± 2.5 m/s. Aortic PWV was independently associated with LV ejection fraction (ss= -0.406, P = 0.006), LV stroke volume (ss=-0.407, P = 0.001), LV cardiac output (ss= -0.458, P = 0.001), and with cerebral WMHs (P < 0.05). There were no independent associations between aortic stiffness and LV mass, cerebral microbleeds or lacunar infarcts. Aortic stiffness is independently associated with systolic LV function and cerebral WMHs in patients with type 1 DM. (orig.)

  9. Fractal analysis and Gray level co-occurrence matrix method for evaluation of reperfusion injury in kidney medulla.

    Science.gov (United States)

    Pantic, Igor; Nesic, Zorica; Paunovic Pantic, Jovana; Radojević-Škodrić, Sanja; Cetkovic, Mila; Basta Jovanovic, Gordana

    2016-05-21

    Fractal analysis and Gray level co-occurrence matrix method represent two novel mathematical algorithms commonly used in medical sciences as potential parts of computer-aided diagnostic systems. In this study, we tested the ability of these methods to discriminate the kidney medullar tissue suffering from reperfusion injury, from normal tissue. A total of 320 digital micrographs of Periodic acid-Schiff (PAS) - stained kidney medulla from 16 Wistar albino mice (20 per animal), were analyzed using National Institutes of Health ImageJ software (NIH, Bethesda, MD) and its plugins. 160 micrographs were obtained from the experimental group with induced reperfusion injury, and another 160 were obtained from the controls. For each micrograph we calculated the values of fractal dimension, lacunarity, as well as five GLCM features: angular second moment, entropy, inverse difference moment, GLCM contrast, and GLCM correlation. Discriminatory value of the parameters was tested using receiver operating characteristic (ROC) analysis, by measuring the area below ROC curve. The results indicate that certain features of GLCM algorithm have excellent discriminatory ability in evaluation of damaged kidney tissue. Fractal dimension and lacunarity as parameters of fractal analysis also had a relatively good discriminatory value in differentiation of injured from the normal tissue. Both methods have potentially promising application in future design of novel techniques applicable in cell physiology, histology and pathology. PMID:26964774

  10. MRI and pathological examination of post-mortem brains: the problem of white matter high signal areas

    Energy Technology Data Exchange (ETDEWEB)

    Scarpelli, M. (Inst. of Pathological Anatomy and Histopathology, Ancona Univ. (Italy)); Salvolini, U. (Magnetic Resonance Research Unit, Ancona Univ. (Italy)); Diamanti, L. (Inst. of Pathological Anatomy and Histopathology, Ancona Univ. (Italy)); Montironi, R. (Inst. of Pathological Anatomy and Histopathology, Ancona Univ. (Italy)); Chiaromoni, L. (Magnetic Resonance Research Unit, Ancona Univ. (Italy)); Maricotti, M. (Magnetic Resonance Research Unit, Ancona Univ. (Italy))

    1994-07-01

    We examined 21 brains from individuals more than 65 years of age by MRI and neuropathological methods to study the frequency and morphology of white matter changes. There were 16 brains from neurologically normal subjects (Group 1) while the remaining 5 (Group 2) had neurological disturbances. In Group 1 MRI showed high signal areas in the periventricular white matter in 12 brains and in the deep white matter in 9. All had focal areas, with confluent zones in 4; 3 cystic infarcts were also detected. Neuropathology in this Group showed periventricular changes of variable extent in all cases, vacuolated myelin around the perivascular spaces in 14 and degenerate myelin in 4. Macroscopic inspection showed 3 cystic lacunar infarcts, while areas of recent infarction were present on histology in 2. Four of the Group 2 brains had periventricular MRI changes; high signal areas in deep white matter were focal in 2 and confluent in 1. Cystic infarcts were detected in 3 cases. Neuropathology showed periventricular changes in all the brains; in 4 myelin around the perivascular spaces was vacuolated while degenerate myelin was demonstrated in 1. There were also old (1) and recent (2) lacunar infarcts. (orig.)

  11. Racial Differences by Ischemic Stroke Subtype: A Comprehensive Diagnostic Approach

    Directory of Open Access Journals (Sweden)

    Sarah Song

    2012-01-01

    Full Text Available Background. Previous studies have suggested that black populations have more small-vessel and fewer cardioembolic strokes. We sought to analyze racial differences in ischemic stroke subtype employing a comprehensive diagnostic workup with magnetic resonance-imaging-(MRI- based evaluation including diffusion-weighted imaging (DWI. Methods. 350 acute ischemic stroke patients admitted to an urban hospital with standardized comprehensive diagnostic evaluations were retrospectively analyzed. Ischemic stroke subtype was determined by three Trial of Org 10172 in Acute Stroke Treatment (TOAST classification systems. Results. We found similar proportions of cardioembolic and lacunar strokes in the black and white cohort. The only subtype category with a significant difference by race was “stroke of other etiology,” more common in whites. Black stroke patients were more likely to have an incomplete evaluation, but this did not reach significance. Conclusions. We found similar proportions by race of cardioembolic and lacunar strokes when employing a full diagnostic evaluation including DWI MRI. The relatively high rate of cardioembolism may have been underappreciated in black stroke patients when employing a CT approach to stroke subtype diagnosis. Further research is required to better understand the racial differences in frequency of “stroke of other etiology” and explore disparities in the extent of diagnostic evaluations.

  12. On the fractal distribution of primes and prime-indexed primes by the binary image analysis

    Science.gov (United States)

    Cattani, Carlo; Ciancio, Armando

    2016-10-01

    In this paper, the distribution of primes and prime-indexed primes (PIPs) is studied by mapping primes into a binary image which visualizes the distribution of primes. These images show that the distribution of primes (and PIPs) is similar to a Cantor dust, moreover the self-similarity with respect to the order of PIPs (already proven in Batchko (2014)) can be seen as an invariance of the binary images. The index of primes plays the same role of the scale for fractals, so that with respect to the index the distribution of prime-indexed primes is characterized by the self-similarity alike any other fractal. In particular, in order to single out the scale dependence, the PIPs fractal distribution will be evaluated by limiting to two parameters, fractal dimension (δ) and lacunarity (λ), that are usually used to measure the fractal nature. Because of the invariance of the corresponding binary plots, the fractal dimension and lacunarity of primes distribution are invariant with respect to the index of PIPs.

  13. Fostering Effective Studying and Study Planning with Study Questions

    Science.gov (United States)

    Wilhelm, Pascal; Pieters, Jules M.

    2007-01-01

    In a course on biological psychology and neuropsychology, study questions were provided that also appeared as test questions in the course exam. This method was introduced to support students in active processing and reproduction of the study texts, and study planning. Data were gathered to test the hypothesis that study question use would be…

  14. Quantitative imaging of alveolar recruitment with hyperpolarized gas MRI during mechanical ventilation.

    Science.gov (United States)

    Cereda, Maurizio; Emami, Kiarash; Kadlecek, Stephen; Xin, Yi; Mongkolwisetwara, Puttisarn; Profka, Harrilla; Barulic, Amy; Pickup, Stephen; Månsson, Sven; Wollmer, Per; Ishii, Masaru; Deutschman, Clifford S; Rizi, Rahim R

    2011-02-01

    The aim of this study was to assess the utility of (3)He MRI to noninvasively probe the effects of positive end-expiratory pressure (PEEP) maneuvers on alveolar recruitment and atelectasis buildup in mechanically ventilated animals. Sprague-Dawley rats (n = 13) were anesthetized, intubated, and ventilated in the supine position ((4)He-to-O(2) ratio: 4:1; tidal volume: 10 ml/kg, 60 breaths/min, and inspiration-to-expiration ratio: 1:2). Recruitment maneuvers consisted of either a stepwise increase of PEEP to 9 cmH(2)O and back to zero end-expiratory pressure or alternating between these two PEEP levels. Diffusion MRI was performed to image (3)He apparent diffusion coefficient (ADC) maps in the middle coronal slices of lungs (n = 10). ADC was measured immediately before and after two recruitment maneuvers, which were separated from each other with a wait period (8-44 min). We detected a statistically significant decrease in mean ADC after each recruitment maneuver. The relative ADC change was -21.2 ± 4.1 % after the first maneuver and -9.7 ± 5.8 % after the second maneuver. A significant relative increase in mean ADC was observed over the wait period between the two recruitment maneuvers. The extent of this ADC buildup was time dependent, as it was significantly related to the duration of the wait period. The two postrecruitment ADC measurements were similar, suggesting that the lungs returned to the same state after the recruitment maneuvers were applied. No significant intrasubject differences in ADC were observed between the corresponding PEEP levels in two rats that underwent three repeat maneuvers. Airway pressure tracings were recorded in separate rats undergoing one PEEP maneuver (n = 3) and showed a significant relative difference in peak inspiratory pressure between pre- and poststates. These observations support the hypothesis of redistribution of alveolar gas due to recruitment of collapsed alveoli in presence of atelectasis, which was also supported by

  15. Marked pericardial inhomogeneity of specific ventilation at total lung capacity and beyond

    DEFF Research Database (Denmark)

    Sun, Yanping; Butler, James P; Lindholm, Peter;

    2009-01-01

    We measured regional ventilation at 1l above functional residual capacity (FRC+1L) and total lung capacity (TLC) in three normal subjects and four elite breath-hold divers, and above TLC after glossopharyngeal insufflation (TLC+GI) in the divers. Hyperpolarized (3)He MRI was used to map the local...... ventilation per unit volume over the entire lung. At TLC and above, there was markedly increased regional ventilation of the lungs in the pericardial region compared with the relatively uniform ventilation throughout the rest of the lung. The distribution of fractional ventilation regionally was relatively...

  16. Hyperpolarized 3He apparent diffusion coefficient MRI of the lung: reproducibility and volume dependency in healthy volunteers and patients with emphysema

    DEFF Research Database (Denmark)

    Diaz, S.; Casselbrant, I.; Piitulainen, E.;

    2008-01-01

    PURPOSE: To measure the apparent diffusion coefficient (ADC) of hyperpolarized (HP) (3)He gas using diffusion weighted MRI in healthy volunteers and patients with emphysema and examine the reproducibility and volume dependency. MATERIALS AND METHODS: A total of eight healthy volunteers and 16...... in mean ADC with increased inhaled gas volume was observed in both groups. CONCLUSION: Mean ADC and SD of HP (3)He MRI is reproducible and discriminates well between healthy controls and patients with emphysema at the higher gas volume. This method is robust and may be useful to gain new insights...

  17. Case Study: Writing a Journal Case Study

    Science.gov (United States)

    Prud'homme-Genereux, Annie

    2016-01-01

    This column provides original articles on innovations in case study teaching, assessment of the method, as well as case studies with teaching notes. This month's issue describes incorporating a journal article into the classroom by first converting it into a case study.

  18. Building Transdisciplinary Environmental Studies

    DEFF Research Database (Denmark)

    Holm, Jesper

    2006-01-01

    Conceptual analytical-methodological conceptualization of crossdisciplinary sustainability studies......Conceptual analytical-methodological conceptualization of crossdisciplinary sustainability studies...

  19. German Studies in America. German Studies Notes.

    Science.gov (United States)

    Sander, Volkmar; Osterle, Heinz D.

    This volume contains two papers, "German Studies in America," by Volkmar Sander, and "Historicism, Marxism, Structuralism: Ideas for German Culture Courses," by Heinz D. Osterle. The first paper discusses the position of German studies in the United States today. The greatest challenge comes from low enrollments; therefore, German departments must…

  20. 2001-2011

    DEFF Research Database (Denmark)

    Poggesi, Anna; Pantoni, Leonardo; Inzitari, Domenico;

    2011-01-01

    they are associated, in cross-sectional surveys, with various disturbances and, in follow-up studies, with poor prognosis. The Leukoaraiosis And DISability (LADIS) study has contributed substantially to this body of knowledge. LADIS is a European multicenter collaboration that was started in 2001 with the aim...... of assessing the independent role of WMC in predicting disability in subjects aged 65-84. The main results of the LADIS study have been released in 2009 with the demonstration that severe WMC more than double the risk of transition from an autonomous to a dependent status after 3 years of follow-up. The LADIS...... study has also contributed more focused substudies assessing the possible role of WMC in the decline of cognitive and motor performances, depressive symptoms associated with aging and cerebrovascular diseases, urinary disturbances, and also the role of other brain lesions (lacunar infarcts, cerebral...

  1. Mechanisms of osteocyte stimulation in osteoporosis.

    Science.gov (United States)

    Verbruggen, Stefaan W; Vaughan, Ted J; McNamara, Laoise M

    2016-09-01

    Experimental studies have shown that primary osteoporosis caused by oestrogen-deficiency results in localised alterations in bone tissue properties and mineral composition. Additionally, changes to the lacunar-canalicular architecture surrounding the mechanosensitive osteocyte have been observed in animal models of the disease. Recently, it has also been demonstrated that the mechanical stimulation sensed by osteocytes changes significantly during osteoporosis. Specifically, it was shown that osteoporotic bone cells experience higher maximum strains than healthy bone cells after short durations of oestrogen deficiency. However, in long-term oestrogen deficiency there was no significant difference between bone cells in healthy and normal bone. The mechanisms by which these changes arise are unknown. In this study, we test the hypothesis that complex changes in tissue composition and lacunar-canalicular architecture during osteoporosis alter the mechanical stimulation of the osteocyte. The objective of this research is to employ computational methods to investigate the relationship between changes in bone tissue composition and microstructure and the mechanical stimulation of osteocytes during osteoporosis. By simulating physiological loading, it was observed that an initial decrease in tissue stiffness (of 0.425GPa) and mineral content (of 0.66wt% Ca) relative to controls could explain the mechanical stimulation observed at the early stages of oestrogen deficiency (5 weeks post-OVX) during in situ bone cell loading in an oestrogen-deficient rat model of post-menopausal osteoporosis (Verbruggen et al., 2015). Moreover, it was found that a later increase in stiffness (of 1.175GPa) and mineral content (of 1.64wt% Ca) during long-term osteoporosis (34 weeks post-OVX), could explain the mechanical stimuli previously observed at a later time point due to the progression of osteoporosis. Furthermore, changes in canalicular tortuosity arising during osteoporosis were shown

  2. Mechanisms of osteocyte stimulation in osteoporosis.

    Science.gov (United States)

    Verbruggen, Stefaan W; Vaughan, Ted J; McNamara, Laoise M

    2016-09-01

    Experimental studies have shown that primary osteoporosis caused by oestrogen-deficiency results in localised alterations in bone tissue properties and mineral composition. Additionally, changes to the lacunar-canalicular architecture surrounding the mechanosensitive osteocyte have been observed in animal models of the disease. Recently, it has also been demonstrated that the mechanical stimulation sensed by osteocytes changes significantly during osteoporosis. Specifically, it was shown that osteoporotic bone cells experience higher maximum strains than healthy bone cells after short durations of oestrogen deficiency. However, in long-term oestrogen deficiency there was no significant difference between bone cells in healthy and normal bone. The mechanisms by which these changes arise are unknown. In this study, we test the hypothesis that complex changes in tissue composition and lacunar-canalicular architecture during osteoporosis alter the mechanical stimulation of the osteocyte. The objective of this research is to employ computational methods to investigate the relationship between changes in bone tissue composition and microstructure and the mechanical stimulation of osteocytes during osteoporosis. By simulating physiological loading, it was observed that an initial decrease in tissue stiffness (of 0.425GPa) and mineral content (of 0.66wt% Ca) relative to controls could explain the mechanical stimulation observed at the early stages of oestrogen deficiency (5 weeks post-OVX) during in situ bone cell loading in an oestrogen-deficient rat model of post-menopausal osteoporosis (Verbruggen et al., 2015). Moreover, it was found that a later increase in stiffness (of 1.175GPa) and mineral content (of 1.64wt% Ca) during long-term osteoporosis (34 weeks post-OVX), could explain the mechanical stimuli previously observed at a later time point due to the progression of osteoporosis. Furthermore, changes in canalicular tortuosity arising during osteoporosis were shown

  3. Infarctions in the vascular territory of the posterior cerebral artery: clinical features in 232 patients

    Directory of Open Access Journals (Sweden)

    Parra Olga

    2011-09-01

    Full Text Available Abstract Background Ischemic stroke caused by infarction in the territory of the posterior cerebral artery (PCA has not been studied as extensively as infarctions in other vascular territories. This single centre, retrospective clinical study was conducted a to describe salient characteristics of stroke patients with PCA infarction, b to compare data of these patients with those with ischaemic stroke due to middle cerebral artery (MCA and anterior cerebral artery (ACA infarctions, and c to identify predictors of PCA stroke. Findings A total of 232 patients with PCA stroke were included in the "Sagrat Cor Hospital of Barcelona Stroke Registry" during a period of 19 years (1986-2004. Data from stroke patients are entered in the stroke registry following a standardized protocol with 161 items regarding demographics, risk factors, clinical features, laboratory and neuroimaging data, complications and outcome. The characteristics of these 232 patients with PCA stroke were compared with those of the 1355 patients with MCA infarctions and 51 patients with ACA infarctions included in the registry. Infarctions of the PCA accounted for 6.8% of all cases of stroke (n = 3808 and 9.6% of cerebral infarctions (n = 2704. Lacunar infarction was the most frequent stroke subtype (34.5% followed by atherothrombotic infarction (29.3% and cardioembolic infarction (21.6%. In-hospital mortality was 3.9% (n = 9. Forty-five patients (19.4% were symptom-free at hospital discharge. Hemianopia (odds ratio [OR] = 6.43, lacunar stroke subtype (OR = 2.18, symptom-free at discharge (OR = 1.92, limb weakness (OR = 0.10, speech disorders (OR = 0.33 and cardioembolism (OR = 0.65 were independent variables of PCA stroke in comparison with MCA infarction, whereas sensory deficit (OR = 2.36, limb weakness (OR = 0.11 and cardioembolism as stroke mechanism (OR = 0.43 were independent variables associated with PCA stroke in comparison with ACA infarction. Conclusions Lacunar stroke is

  4. Esophagram (Barium Swallow Study)

    Science.gov (United States)

    ... esophagram is a study that is completed in radiology. The test evaluates the esophagus. The esophagus is ... to wear. The study is completed in a radiology (x-ray/fluoroscopy) room. If a child is ...

  5. 522 Postmarket Surveillance Studies

    Data.gov (United States)

    U.S. Department of Health & Human Services — The 522 Postmarket Surveillance Studies Program encompasses design, tracking, oversight, and review responsibilities for studies mandated under section 522 of the...

  6. FEMA DFIRM Study Info

    Data.gov (United States)

    Minnesota Department of Natural Resources — This table contains details about the study such as the study name, datum, projection, etc. There is normally only one record in this table for each Flood Insurance...

  7. Current Research Studies

    Science.gov (United States)

    ... Home > Explore CCFA Research > Current Research Studies Current Research Studies Email Print + Share The Crohn’s & Colitis Foundation ... online. Learn more about CCFA Partners. CCFA Clinical Research Alliance The Clinical Research Alliance is a network ...

  8. Excellence in Social Studies.

    Science.gov (United States)

    Durfee, David A.

    1986-01-01

    Discusses a strategy for unifying and improving the social studies curriculum through an "outcomes sought" approach. Outlines eight measurable qualities students completing social studies should have achieved. Discusses implications of this approach. (LP)

  9. The Study of Algae

    Science.gov (United States)

    Rushforth, Samuel R.

    1977-01-01

    Included in this introduction to the study of algae are drawings of commonly encountered freshwater algae, a summary of the importance of algae, descriptions of the seven major groups of algae, and techniques for collection and study of algae. (CS)

  10. Post-Approval Studies

    Data.gov (United States)

    U.S. Department of Health & Human Services — The CDRH Post-Approval Studies Program encompasses design, tracking, oversight, and review responsibilities for studies mandated as a condition of approval of a...

  11. Chemical Industry Bandwidth Study

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2006-12-01

    The Chemical Bandwidth Study provides a snapshot of potentially recoverable energy losses during chemical manufacturing. The advantage of this study is the use of "exergy" analysis as a tool for pinpointing inefficiencies.

  12. Future Circular Collider Study

    CERN Document Server

    Benedikt, Michael

    2014-01-01

    This presentation has been given during the 1st EuCARD-2 annual meeting. It contains: • Motivation & scope • Parameters & design challenges • Study organization, study time line • Preparing global FCC collaboration • Summary

  13. Medicinsk forbedring: study drugs

    OpenAIRE

    Holm Sørensen, Camilla; Juul Asmussen, Melanie; Constantin, Liv; Haugtved, Claire Rigmor

    2015-01-01

    This study investigates medical optimization regarding cognitive enhancement. Study drugs are performance-enhancing drugs that people use in terms of optimizing cognitive skills. The use of study drugs has turned out to have a beneficial effect when it comes to perform in stressful situations for example an examination. The purpose of our project is to analyze central arguments for and against the use of study drugs. We analyze two arguments for and three arguments that express a statem...

  14. CISSP study guide

    CERN Document Server

    Conrad, Eric; Feldman, Joshua; Riggins, Kevin

    2011-01-01

    "The Eleventh Hour CISSP Study Guide" is keyed to the latest CISSP exam. This book is streamlined to include only core certification information and is presented for ease of last-minute studying. Main objectives of the exam are covered concisely with key concepts highlighted. This is the only guide you need for last-minute studying. This title answers the toughest questions and highlights core topics. This title can be paired with any other study guide so you are completely prepared.

  15. Social Psychoanalytic Disability Studies

    Science.gov (United States)

    Goodley, Dan

    2011-01-01

    This paper explores connections and tensions between psychoanalysis and disability studies. The first part of the paper considers contemporaneous engagements with the psyche by a number of disability studies writers. These scholars have remained accountable to a politicised disability studies but have pushed for critical encounters with the…

  16. Defining (Conceptualizing) Social Studies.

    Science.gov (United States)

    Shaver, James P.

    1990-01-01

    Critiques James Barth, Robert Barr, and Sam Shermis' three social studies traditions theory and National Commission on Social Studies task force report. Argues first falsely splits essential social studies components; second creates a curricular hodgepodge. Highlights need to consider values as both affective and cognitive and to create…

  17. Humanities, Digital Humanities, Media studies, Internet studies

    DEFF Research Database (Denmark)

    Brügger, Niels

    Todays expanding digital landscape constitutes an important research object as well as the research environment for the Humanities at the beginning of the 21st century. Taking this state of affairs as a starting point this inaugural lecture presents a vision for how the digital affects the interp......Todays expanding digital landscape constitutes an important research object as well as the research environment for the Humanities at the beginning of the 21st century. Taking this state of affairs as a starting point this inaugural lecture presents a vision for how the digital affects...... the interplay between four areas which until now to a certain extent have been separated: Traditional Hu- manities, Digital Humanities, Media studies, and Internet studies. The vision is followed by an outline of how it can be unfolded in concrete activities, in the form of research projects, research...

  18. Study deep geothermal energy; Studie dypgeotermisk energi

    Energy Technology Data Exchange (ETDEWEB)

    Havellen, Vidar; Eri, Lars Sigurd; Andersen, Andreas; Tuttle, Kevin J.; Ruden, Dorottya Bartucz; Ruden, Fridtjof; Rigler, Balazs; Pascal, Christophe; Larsen, Bjoern Tore

    2012-07-01

    The study aims to analyze the potential energy with current technology, challenges, issues and opportunities for deep geothermal energy using quantitative analysis. It should especially be made to identify and investigate critical connections between geothermal potential, the size of the heating requirements and technical solutions. Examples of critical relationships may be acceptable cost of technology in relation to heating, local geothermal gradient / drilling depth / temperature levels and profitability. (eb)

  19. Studying Engineering Practice

    DEFF Research Database (Denmark)

    Buch, Anders

    2015-01-01

    The study of engineering practices has been the focus of Engineering Studies over the last three decades. Theses studies have used ethnographic and grounded methods in order to investigate engineering practices as they unfold in natural settings - in workplaces and engineering education. However......, engineering studies have not given much attention to conceptually clarifying what should be understood by 'engineering practices' and more precisely account for the composition and organization of the entities and phenomena that make up the practices. This chapter investigates and discusses how a 'practice...... will draw out some methodological consequences and discuss the ramifications of a practice theoretical approach for Engineering Studies....

  20. 4-D segmentation and normalization of 3He MR images for intrasubject assessment of ventilated lung volumes

    Science.gov (United States)

    Contrella, Benjamin; Tustison, Nicholas J.; Altes, Talissa A.; Avants, Brian B.; Mugler, John P., III; de Lange, Eduard E.

    2012-03-01

    Although 3He MRI permits compelling visualization of the pulmonary air spaces, quantitation of absolute ventilation is difficult due to confounds such as field inhomogeneity and relative intensity differences between image acquisition; the latter complicating longitudinal investigations of ventilation variation with respiratory alterations. To address these potential difficulties, we present a 4-D segmentation and normalization approach for intra-subject quantitative analysis of lung hyperpolarized 3He MRI. After normalization, which combines bias correction and relative intensity scaling between longitudinal data, partitioning of the lung volume time series is performed by iterating between modeling of the combined intensity histogram as a Gaussian mixture model and modulating the spatial heterogeneity tissue class assignments through Markov random field modeling. Evaluation of the algorithm was retrospectively applied to a cohort of 10 asthmatics between 19-25 years old in which spirometry and 3He MR ventilation images were acquired both before and after respiratory exacerbation by a bronchoconstricting agent (methacholine). Acquisition was repeated under the same conditions from 7 to 467 days (mean +/- standard deviation: 185 +/- 37.2) later. Several techniques were evaluated for matching intensities between the pre and post-methacholine images with the 95th percentile value histogram matching demonstrating superior correlations with spirometry measures. Subsequent analysis evaluated segmentation parameters for assessing ventilation change in this cohort. Current findings also support previous research that areas of poor ventilation in response to bronchoconstriction are relatively consistent over time.

  1. Event studies in Turkey

    Directory of Open Access Journals (Sweden)

    Ulkem Basdas

    2014-09-01

    Full Text Available The primary goal of this paper is to review the event studies conducted for Turkey to in order to identify the common components in their designs. This paper contributes to the existing literature by reviewing all event studies for Turkey for the first time, but more importantly; this review leads to the upcoming event studies on Turkey by highlighting main components of a proper design. Based on the review of 75 studies, it is observed that event studies generally choose BIST-100 (formerly, ISE-100 market index and market adjusted returns with the parametric tests. In general, the studies prefer to rely on one type of model to calculate abnormal returns without discussing the selection of the underlying model. Especially for the event studies focusing on the impact of political events or macroeconomic announcements in Turkey, there is a risk of clustering due to the application of same event date for all observations.

  2. Usefulness of the second derivative of the finger photoplethysmogram for assessment of end-organ damage: the J-SHIPP study.

    Science.gov (United States)

    Tabara, Yasuharu; Igase, Michiya; Okada, Yoko; Nagai, Tokihisa; Miki, Tetsuro; Ohyagi, Yasumasa; Matsuda, Fumihiko; Kohara, Katsuhiko

    2016-07-01

    Early detection of pathological changes in the vasculature is required to identify individuals at risk of cardiovascular diseases. Noninvasive measurement of the second derivative of photoplethysmogram (SDPTG) might aid in evaluating vascular aging. Here we clarified the diagnostic significance of four SDPTG indices for end-organ damage. A total of 1613 community residents (65±10 years) were enrolled. Changes in blood flow volume at the forefinger were measured by photoplethysmography. SDPTG was computationally calculated from the plethysmogram, and the height of five peaks (a-e) on the SDPTG was measured. Carotid intima-media thickness (IMT), brachial-to-ankle pulse wave velocity (baPWV) and silent cerebral lesions were used as indices of end-organ damage. Multivariate analysis identified age, sex, systolic blood pressure and heart rate as strong determinants for the evaluated SDPTG indices, namely b/a, d/a and aging index ([b-d-c-e]/a). In addition, poor glycemic control and carotid IMT were also weakly associated with the SDPTG indices. Compared with other established risk factors, however, the association between the SDPTG indices and carotid IMT was weak or insignificant (b/a: β=0.069, P=0.002; d/a: β=-0.009, P=0.669; and aging index: β=0.047, P=0.037). Further, no significant association was noted between the SDPTG indices and silent lacunar infarction (b/a: P=0.111; d/a: P=0.263; and aging index: P=0.167) and periventricular hyperintensity (b/a: P=0.587; d/a: P=0.254; and aging index: P=0.429). Although the SDPTG indices evaluated here might represent structural and functional changes in arteries, they exhibited limited diagnostic significance for pathophysiological changes in large arteries, as well as small vessel diseases of the brain. PMID:26911232

  3. Cross-cultural studies using a modified mini mental test for healthy subjects and patients with various forms of vascular dementia.

    Science.gov (United States)

    Thajeb, Peterus; Thajeb, Teguh; Dai, Daofu

    2007-03-01

    Existing neuropsychological tests are often complex and time-consuming. We designed a modified Mini Mental Test (MMT) battery for clinical assessment of the global and regional higher cortical functions of the brain. We tested its applicability in healthy subjects with different ethnic, cultural and educational backgrounds. The usefulness of our MMT as a tool for the clinical evaluation of patients with various forms of vascular dementia was determined. The MMT comprises five subtests, including clinical evaluations of: (A) orientation (6 points); (B) attention, right-left discrimination, speech, and calculation (20); (C) immediate recall, and recent and remote memory retrieval (10); (D) praxis (10); and (E) visuospatial orientation, agnosia, hemianopsia, and visual hemineglect (14). The MMT was administered to 100 healthy subjects from two different ethnic backgrounds (Indonesian and Chinese/Taiwanese) and diverse cultural and educational backgrounds, and to 61 patients with various forms of vascular dementia. MMT scores were significantly lower in healthy subjects with a low level of education regardless of their ethnic background (p<0.001). Patients with vascular dementia had much lower MMT scores than did the comparable age-adjusted normal controls (p<0.001). Of the patients with vascular dementia, those with Binswanger's disease had the lowest MMT scores (25.5+/-28.9), followed by those with large cerebral infarcts (48.0+/-7.1), cerebral haemorrhage (49.0+/-8.5), and multiple lacunar infarctions (55.0+/-0.5) (P<0.001). With a cut-off point of 33/55 (partial score/total score), the sensitivity and positive predictive value of the MMT were 0.98 and 0.94, respectively. The MMT is a simple and useful tool for clinical assessment of the cognitive functions of healthy subjects and patients with or without vascular dementia. It can be used for individuals with different ethnic, cultural and educational backgrounds. PMID:17258132

  4. Cross-cultural studies using a modified mini mental test for healthy subjects and patients with various forms of vascular dementia.

    Science.gov (United States)

    Thajeb, Peterus; Thajeb, Teguh; Dai, Daofu

    2007-03-01

    Existing neuropsychological tests are often complex and time-consuming. We designed a modified Mini Mental Test (MMT) battery for clinical assessment of the global and regional higher cortical functions of the brain. We tested its applicability in healthy subjects with different ethnic, cultural and educational backgrounds. The usefulness of our MMT as a tool for the clinical evaluation of patients with various forms of vascular dementia was determined. The MMT comprises five subtests, including clinical evaluations of: (A) orientation (6 points); (B) attention, right-left discrimination, speech, and calculation (20); (C) immediate recall, and recent and remote memory retrieval (10); (D) praxis (10); and (E) visuospatial orientation, agnosia, hemianopsia, and visual hemineglect (14). The MMT was administered to 100 healthy subjects from two different ethnic backgrounds (Indonesian and Chinese/Taiwanese) and diverse cultural and educational backgrounds, and to 61 patients with various forms of vascular dementia. MMT scores were significantly lower in healthy subjects with a low level of education regardless of their ethnic background (p<0.001). Patients with vascular dementia had much lower MMT scores than did the comparable age-adjusted normal controls (p<0.001). Of the patients with vascular dementia, those with Binswanger's disease had the lowest MMT scores (25.5+/-28.9), followed by those with large cerebral infarcts (48.0+/-7.1), cerebral haemorrhage (49.0+/-8.5), and multiple lacunar infarctions (55.0+/-0.5) (P<0.001). With a cut-off point of 33/55 (partial score/total score), the sensitivity and positive predictive value of the MMT were 0.98 and 0.94, respectively. The MMT is a simple and useful tool for clinical assessment of the cognitive functions of healthy subjects and patients with or without vascular dementia. It can be used for individuals with different ethnic, cultural and educational backgrounds.

  5. Translation Studies: an overview

    Directory of Open Access Journals (Sweden)

    Cristina García de Toro

    2008-04-01

    Full Text Available The article briefly outlines the main schools and approaches that make up the current landscape of Translation Studies. The purpose of this paper is to offer an introduction to translation theory for those who are beginning their studies in this field or whose knowledge of Translation Studies is tangential. The article starts with a few preliminary matters, such as the question of what Translation Studies is and how the discipline has been mapped out. Then it moves on to examine the theoretical considerations that have been developed since the second half of the 20th century, with special attention being paid to the most recent decades. In this section, which is devoted to theoretical considerations, I will review some of the fundamental issues from a theories of equivalence and comparisons between languages; b functionalist theories; c discursive approaches; d polysystem theory, descriptive studies and norms; e cultural studies; f philosophical theories; g latest contributions to the field of Translation Studies; and h interdisciplinary and integrating approaches. Keywords: translation studies, contemporary theories, linguistic approaches, descriptive studies, cultural studies.

  6. International user studies

    DEFF Research Database (Denmark)

    Nielsen, Lene; Madsen, Sabine; Jensen, Iben;

    the countries/regions they operate in. Instead, they focus on a few strategic markets. International user studies tend to be large-scale studies that involve the effort of many both internal and external/local human resources. The studies typically cover 2-4 countries/regions and many end users in each country...... a company’s general attitude and approach to (1) international markets and (2) user studies. Lastly, we present the theoretical ideas and concepts about culture that has informed the research....

  7. Studies on seismic waves

    Institute of Scientific and Technical Information of China (English)

    张海明; 陈晓非

    2003-01-01

    The development of seismic wave study in China in the past four years is reviewed. The discussion is divided into several aspects, including seismic wave propagation in laterally homogeneous media, laterally heterogeneous media, anisotropic and porous media, surface wave and seismic wave inversion, and seismic wave study in prospecting and logging problems. Important projects in the current studies on seismic wave is suggested as the development of high efficient numerical methods, and applying them to the studies of excitation and propagation of seismic waves in complex media and strong ground motion, which will form a foundation for refined earthquake hazard analysis and prediction.

  8. Contemporary American Chinese Studies

    Institute of Scientific and Technical Information of China (English)

    Qiu Huafei

    2008-01-01

    The rise of modern American scholarship on China was largely attributed to the establishment of the American Joint Committee on Contemporary China (JCCC) in 1959 which sponsored all kinds of activities to promote Chinese studies, ranging from institutional support and financial resources to training courses. Since then, American study of China has entered into a period of sustainability that features academic and group-oriented research. It has become a mainstream discipline in American social science studies.1 There are some distinctive differences between early sinology and modern Chinese Studies: the latter is much more concentrated on the study of issues, comparative historical studies, and contemporary Chinese society. American Chinese studies stresses empirical research, textual data, and the application of theory to practice.Shanghai. He was a Fulbright visiting professor at State University of New York at Geneseo from 2006-2007. This treatise is one of a series of studies for China's National Research Foundation of Philosophy and Social Science (05BGJ012), "American Chinese Studies."

  9. Why Study in Australia?

    Institute of Scientific and Technical Information of China (English)

    丁丽丽

    2014-01-01

    Going overseas to pursue further studies is even more generalized in recent years. Students are open to a variety of op-tions to decide which country to go and which university to choose. Why wouldn’t you want to study with some of the best minds in the world? Australia is a leading global education power, with world’s best educators and facilities. It also provides both local and international students with a variety of quality study options. This essay presents some of the important reasons why in-ternational students should study in Australia in regard to education quality, affordable fees, government support, multiple cultures and immigration policies.

  10. Project management case studies

    CERN Document Server

    Kerzner, Harold R

    2013-01-01

    A new edition of the most popular book of project management case studies, expanded to include more than 100 cases plus a ""super case"" on the Iridium Project Case studies are an important part of project management education and training. This Fourth Edition of Harold Kerzner''s Project Management Case Studies features a number of new cases covering value measurement in project management. Also included is the well-received ""super case,"" which covers all aspects of project management and may be used as a capstone for a course. This new edition:Contains 100-plus case studies drawn from re

  11. Research Studies & Networks

    Science.gov (United States)

    These epidemiological studies may assist in evaluating associations between certain pharmaceuticals and disease risk and contain detailed information on pharmaceutical use and disease risk, including cancer.

  12. Information society studies

    CERN Document Server

    Duff, Alistair S

    2013-01-01

    We are often told that we are ""living in an information society"" or that we are ""information workers."" But what exactly do these claims mean, and how might they be verified? In this important methodological study, Alistair S. Duff cuts through the rhetoric to get to the bottom of the ""information society thesis."" Wide-ranging in coverage, this study will be of interest to scholars in information science, communication and media studies and social theory. It is a key text for the newly-unified specialism of information society studies, and an indispensable guide to the future of this disc

  13. Obtaining the borders of urban areas

    CERN Document Server

    Comin, Cesar Henrique; Costa, Luciano da Fontoura

    2015-01-01

    The access to an ever increasing amount of information in the modern world gave rise to the development of many quantitative indicators about urban regions in the globe. Therefore, there is a growing need for a precise definition of how to delimit urban regions, so as to allow proper respective characterization and modeling. Here we present a straightforward methodology to automatically detect urban region borders. The method is based on the density of street crossings around a single seed point associated to the urban area of interest. We exemplify the potential of the methodology by characterizing the geometry and topology of 21 urban regions obtained from 8 distinct countries. The geometry is studied by employing the lacunarity measurement, which is associated to the regularity of holes contained in a pattern. The topology is analyzed by associating the betweenness centrality of the streets with their respective class, such as motorway or residential, obtained from a database.

  14. A diffusion-based approach to obtaining the borders of urban areas

    Science.gov (United States)

    Henrique Comin, Cesar; Nascimento Silva, Filipi; da Fontoura Costa, Luciano

    2016-05-01

    The access to an ever increasing amount of information in the modern world gave rise to the development of many quantitative indicators about urban regions in the globe. Therefore, there is a growing need for a precise definition of how to delimit urban regions, so as to allow proper respective characterization and modeling. Here we present a straightforward methodology to automatically detect urban region borders around a single seed point. The method is based on a diffusion process having street crossings and terminations as source points. We exemplify the potential of the methodology by characterizing the geometry and topology of 21 urban regions obtained from 8 distinct countries. The geometry is studied by employing the lacunarity measurement, which is associated to the regularity of holes contained in a pattern. The topology is analyzed by associating the betweenness centrality of the streets with their respective class, such as motorway or residential, obtained from a database.

  15. Thermal properties of composite materials: a complex systems approximation

    Science.gov (United States)

    Carrillo, J. L.; Bonilla, Beatriz; Reyes, J. J.; Dossetti, Victor

    We propose an effective media approximation to describe the thermal diffusivity of composite samples made of polyester resin and magnetite inclusions. By means of photoacoustic spectroscopy, the thermal diffusivity of the samples were experimentally measured. The volume fraction of the inclusions was systematically varied in order to study the changes in the effective thermal diffusivity of the composites. For some samples, a static magnetic field was applied during the polymerization process, resulting in anisotropic inclusion distributions. Our results show a significant difference in the thermal properties of the anisotropic samples, compared to the isotropic randomly distributed. We correlate some measures of the complexity of the inclusion structure with the observed thermal response through a multifractal analysis. In this way, we are able to describe, and at some extent predict, the behavior of the thermal diffusivity in terms of the lacunarity and other measures of the complexity of these samples Partial Financial Support by CONACyT México and VIEP-BUAP.

  16. Lipid Transport through the Fetoplacental Barrier by the Fatty Acid-Binding Proteins in Pregnant Women with Herpes Virus Infection in the third Trimester

    Directory of Open Access Journals (Sweden)

    Michael T. Lucenko, PhD, ScD

    2012-12-01

    Full Text Available In this study, the transport of the long chain polyunsaturated fatty acids (LCPUFAs from the lacunar blood through the syncytiotrophoblast of the placental villi to the fetal cord blood via a saturable protein-mediated mechanism by the heart-type fatty acid-binding proteins (H-FABPs has been examined. Exacerbation of the herpes simplex viruses (HSV-1 in the third trimester of gestation reduces the delivery of the fatty acid-binding proteins to the syncytiotrophoblast. During exacerbation of the HSV-1 infection, the selective transfer of the LCPUFAs across the syncytiotrophoblast basal plasma membrane into the fetal cord blood was observed. The supply of anti-inflammatory ω-3 PUFAs was reduced; however, the inflow of inflammatory arachidonic acid and other ω-6 PUFAs into the fetal blood was increased.

  17. Magnetic resonance in neuroborreliosis

    International Nuclear Information System (INIS)

    Magnetic resonance (MR) is commonly used in diagnosing infections of the central nervous system. The aim of the study is to evaluate central nervous system changes in neuroborreliosis patients. MR examinations were performed in 44 patients with clinical symptoms, epidemiology and laboratory tests results of neuroborreliosis. Abnormalities were detected in 22 patients. Most of them presented cortico-subcortical atrophy (86%). In 9 cases foci of increased signal in T2-weighted and FLAIR images were observed in white matter. They were single or multiple, located subcorticaly and paraventriculary. In 2 subjects areas of increased signal were found in the brain stem. Central nervous system abnormalities detected with MR are not specific for Lyme disease. They can suggest demyelinating lesions and/or gliosis observed in many nervous system disorders (SM, ADEM, lacunar infarcts). (author)

  18. Using Fractal and Local Binary Pattern Features for Classification of ECOG Motor Imagery Tasks Obtained from the Right Brain Hemisphere.

    Science.gov (United States)

    Xu, Fangzhou; Zhou, Weidong; Zhen, Yilin; Yuan, Qi; Wu, Qi

    2016-09-01

    The feature extraction and classification of brain signal is very significant in brain-computer interface (BCI). In this study, we describe an algorithm for motor imagery (MI) classification of electrocorticogram (ECoG)-based BCI. The proposed approach employs multi-resolution fractal measures and local binary pattern (LBP) operators to form a combined feature for characterizing an ECoG epoch recording from the right hemisphere of the brain. A classifier is trained by using the gradient boosting in conjunction with ordinary least squares (OLS) method. The fractal intercept, lacunarity and LBP features are extracted to classify imagined movements of either the left small finger or the tongue. Experimental results on dataset I of BCI competition III demonstrate the superior performance of our method. The cross-validation accuracy and accuracy is 90.6% and 95%, respectively. Furthermore, the low computational burden of this method makes it a promising candidate for real-time BCI systems. PMID:27255798

  19. Luminescence study of spodumene

    International Nuclear Information System (INIS)

    A comparative study is made of the luminescence of five kinds of spodumene from Minas Gerais, Brazil, studied previously by optical absorption spectroscopy. Natural gemstones are used which, in the course of the experiments, were irradiated with X-rays. (L.C.)

  20. Prolactinomas : clinical studies

    NARCIS (Netherlands)

    Kars, Marleen

    2008-01-01

    Prolactinoma are treated with dopamine agonists, which are effective in reducing prolactin and tumor size. Studies reporting clinical and radiological outcome are scarce. The study described in chapter 2, assesses long-term outcome in patients treated with dopamine agonists for macroprolactinoma. An

  1. Home Study Advertising Handbook.

    Science.gov (United States)

    Lambert, Michael P., Ed.; Welch, Sally R., Ed.

    This handbook contains a collections of nine articles on the subject of direct-response advertising. The handbook gives advice on how to create effective advertisements for home study courses. The nine articles are the following: "Overview of Home Study Advertising in the 1990s" (Michael P. Lambert); "Ad Features that Sell" (Nancie E. Robertson);…

  2. Intrapreneurship - An International Study

    NARCIS (Netherlands)

    Bosma, N.S.; Stam, E.; Wennekers, A.R.M.

    2010-01-01

    This paper presents the first results of a novel international comparative study of intrapreneurship, i.e., employees developing new business activities for their employer. This study is based on an exploratory investigation in the framework of the Global Entrepreneurship Monitor 2008, in which elev

  3. Managerial Accounting. Study Guide.

    Science.gov (United States)

    Plachta, Leonard E.

    This self-instructional study guide is part of the materials for a college-level programmed course in managerial accounting. The study guide is intended for use by students in conjuction with a separate textbook, Horngren's "Accounting for Management Control: An Introduction," and a workbook, Curry's "Student Guide to Accounting for Management…

  4. A Social Studies Imperative.

    Science.gov (United States)

    Engle, Shirley H.

    1985-01-01

    Despite all the technology at educators' disposal, the field of social studies is more uncertain of its goals and more intellectually confused than ever before. The failure to deal in a rigorous and uncluttered way with current social problems is one of the most unconscionable defects in the social studies today. (RM)

  5. E-study

    Institute of Scientific and Technical Information of China (English)

    刘洪毓

    2002-01-01

    The rapid development in inforrnation technology is set to make the average home a virtual (实质上的) university campus. E-study (or online study), the latest trend in distance education, could leave university traditions suchas attending lectures,

  6. Studies of Personality Disorders

    DEFF Research Database (Denmark)

    Ronningstam, Elsa; Simonsen, Erik; Oldham, John M;

    2014-01-01

    The past 25 years have shown major advances in the studies of personality disorders. This collaborative article by the presidents, past and present, of ISSPD reflects on the progress within several significant areas of studies, i.e., assessment, neuroscience, treatment, prevention, advocacy...

  7. Fusion energy studies

    International Nuclear Information System (INIS)

    Current experimental efforts are aimed toward developing cryosorption vacuum pumps for removing unburned fuel and impurities from the plasma, studying deep-bed sorption pumps for roughing and transfer operations, investigating methods for recovery of tritium bred in blankets of lithium or lithium alloys, and studying containment of tritium that permeates metal walls

  8. Simulation in International Studies

    Science.gov (United States)

    Boyer, Mark A.

    2011-01-01

    Social scientists have long worked to replicate real-world phenomena in their research and teaching environments. Unlike our biophysical science colleagues, we are faced with an area of study that is not governed by the laws of physics and other more predictable relationships. As a result, social scientists, and international studies scholars more…

  9. MY ENGLISH STUDY

    Institute of Scientific and Technical Information of China (English)

    孙岩; Roxanne; Lees

    2003-01-01

    I am a student of Yanshan University, majoring in English. I have studied English for a long time, which is full of (and have encountered some) special experiences (in my studies). After graduation from (a) junior (middle) school, I did not go to senior (middle) school for

  10. What Are Sleep Studies?

    Science.gov (United States)

    ... Events Spokespeople Email Alerts E-Newsletters About NHLBI Organization NHLBI Director Budget, Planning, & Legislative Advisory Committees Contact Us FAQs Home » Health Information for the Public » Health Topics » Sleep Studies Explore Sleep Studies What Are... Types Who Needs ...

  11. Studying Human Origins

    NARCIS (Netherlands)

    Corbey, Raymond; Roebroeks, Wil

    2001-01-01

    This history of human origin studies covers a wide range of disciplines. This important new study analyses a number of key episodes from palaeolithic archaeology, palaeoanthropology, primatology and evolutionary theory in terms of various ideas on how one should go about such reconstructions and wha

  12. CDC's Cervical Cancer Study

    Science.gov (United States)

    ... in Cancer Moonshot Stay Informed CDC’s Cervical Cancer Study Language: English Español (Spanish) Recommend on Facebook Tweet ... year. As part of CDC’s Cervical Cancer (Cx3) Study, we surveyed a sample of both health care ...

  13. The CAIRO4 study

    DEFF Research Database (Denmark)

    de Wilt, Johannes H W; Verhoef, Cornelis; Punt, Cornelis J A;

    2016-01-01

    stages of the disease. We here propose a randomized trial in order to demonstrate that resection of the primary tumour improves overall survival. METHODS/DESIGN: The CAIRO4 study is a multicentre, randomized, phase III study of the Dutch Colorectal Cancer Group (DCCG). Patients with synchronous...

  14. The CAIRO4 study

    DEFF Research Database (Denmark)

    't Lam-Boer, Jorine; Mol, Linda; Verhoef, Cornelis;

    2015-01-01

    stages of the disease. We here propose a randomized trial in order to demonstrate that resection of the primary tumour improves overall survival. METHODS/DESIGN: The CAIRO4 study is a multicentre, randomized, phase III study of the Dutch Colorectal Cancer Group (DCCG). Patients with synchronous...

  15. Study Groups in Denmark

    DEFF Research Database (Denmark)

    Hjorth, Poul G.

    2007-01-01

    Since 1998 European Study Groups have been held in Denmark, and Danish companies from LEGO and NOVO to very small high-tech firms have participated. I briefly describe the history, the organisation and the format of the Danish Study Groups, and highlight a few problem solutions....

  16. Energy conversion alternatives study

    Science.gov (United States)

    Shure, L. T.

    1979-01-01

    Comparison of coal based energy systems is given. Study identifies and compares various advanced energy conversion systems using coal or coal derived fuels for baselaoad electric power generation. Energy Conversion Alternatives Study (ECAS) reports provede government, industry, and general public with technically consistent basis for comparison of system's options of interest for fossilfired electric-utility application.

  17. Get Oriented: Study Japan.

    Science.gov (United States)

    Parramore, Barbara M.

    1981-01-01

    Recommends that students in social studies classes be exposed to a study of Japan because of the wide array of contrasts possible between Japan and the United States. Information is presented on Japan's modernization, global status, language, decision-making processes, and ancient traditions. (DB)

  18. English Intonation Studies.

    Science.gov (United States)

    Lewis, Jack Windsor

    This paper is a critical survey of the work of various linguists in the field of English intonation studies. Crystal's work is cited as being particularly influential in the author's work. It is argued that there is a lack of progress in this field because of a preoccupation on the part of scholars with their own studies and their application and…

  19. Pacific Studies: Quo Vadis?

    Directory of Open Access Journals (Sweden)

    Anne Holden Rønning

    2014-02-01

    Full Text Available Looking back to the past this paper discusses why Pacific studies and in particular Australasian studies became an area of interest in tertiary education in Europe. What subject areas initiated these studies, and how do past legacies shape the present? With cutbacks in higher education over the past two decades the future of interdisciplinary studies and the humanities looks bleak. At the same time due to global business and increased political communication across borders there is a vibrant interest in and need for such studies among businesses and students. For most Europeans the literature of settler countries, with their European legacy, makes access to ways of thought and culture easier than studies of countries with other mythological backgrounds. In today’s multicultural environment such studies can provide knowledge for an understanding of other cultures and increase tolerance of the ‘other’. Area studies have relevance to our situation in Europe with increased migrancy, not least as a result of Schengen and EU regulations.

  20. Single Policy Study

    DEFF Research Database (Denmark)

    Kronsell, Annica; Manners, Ian James

    2015-01-01

    Single policy studies are the most common form of European Union (EU) research. Single policy studies are widely used to understand the role of the EU in a wide variety of sectors, together with their development over time, and often offer public policy prescriptions. This chapter discusses...... the relevance of single policy studies in EU research and give examples of how such research can be designed and carried out. The chapter reviews three examples of single policy studies using different methods based on EU environmental policy, the EU biofuels directive, and the EU Common Security and Defence...... Policy (CSDP). The examples are illustrative of how single policy studies can be designed to use different approaches in the analysis: multiple streams approach to policy-making; a comparative hypothesis testing; and feminist institutional theory....

  1. Effective Physics Study Habits

    Science.gov (United States)

    Zettili, Nouredine

    2011-04-01

    We discuss the methods of efficient study habits and how they can be used by students to help them improve learning physics. In particular, we deal with ideas pertaining to the most effective techniques needed to help students improve their physics study skills. These ideas were developed as part of Project IMPACTSEED (IMproving Physics And Chemistry Teaching in SEcondary Education), an outreach grant funded by the Alabama Commission on Higher Education. This project is motivated by a major pressing local need: A large number of high school physics teachers teach out of field. In the presentation, focus on topics such as the skills of how to develop long term memory, how to improve concentration power, how to take class notes, how to prepare for and take exams, how to study scientific subjects such as physics. We argue that the student who conscientiously uses the methods of efficient study habits will be able to achieve higher results than the student who does not; moreover, a student equipped with the proper study skills will spend much less time to learn a subject than a student who has no good study habits. The underlying issue here is not the quantity of time allocated to the study efforts by the student, but the efficiency and quality of actions. This work is supported by the Alabama Commission on Higher Education as part of IMPACTSEED grant.

  2. China's India Studies

    Institute of Scientific and Technical Information of China (English)

    Liu Qian

    2008-01-01

    Over the past 50 years, with the improvement of relationship between India and China, the scope of India studies in China's IR research has been broadened and the new areas of studies are being explored. The research agenda of India studies has already extended to the areas like economy, society, culture, security, national strategy and their impact on both bilateral and international relations. In this situation, the focuses of India studies in China's IR research can be mainly identified as follows: reviews on India's social, political and economic systems; analysis on the national strategy and foreign policy; Sino-Indian relations; India's relations with some international organizations. However, even though many fresh progresses have been made in India studies, the India studies in China's IR research still lag far behind the study of other important countries like the U.S., UK, Russia and Japan, and more problems and challenges will face in the coming future. The paper believes that a fuller understanding of India probably will not make China and India close friends, but it definitely will help to prevent them from becoming fierce enemies.

  3. The correlation between lacunes and microbleeds on magnetic resonance imaging in consecutive 180 patients

    International Nuclear Information System (INIS)

    Microbleeds on T2*-weighted magnetic resonance imaging (MRI) represent a hemorrhagic type of small vessel disease. Small vessel disease causes both intracerebral hemorrhages and lacunar infarctions. We studied clinical background and MRI findings of the patients to clarify the correlation between microbleeds and lacunes. This study consisted of 180 consecutive patients who underwent brain MRI using 1.5T system in our hospital for a year. We obtained T2*-weighted gradient-echo imaging as well as T1 and T2-weighted images. We statistically identified the factors related to the presence of microbleeds in all patients. The distribution of lacunes and microbleeds on MRI was compared to clarify the correlation of the lesions in the patients who had both lesions. The overall prevalence of microbleeds was 41.1% (74 of 180 patients). Logistic regression analysis indicated that previous stroke, leukoaraiosis and lacunes were significantly correlated with microbleeds. In the patients who have both microbleeds and lacunes, lesions are tended to locate in thalamus and basal ganglia, especially incidence of lacunes are significantly greater compared with other regions. Thirty-six of 398 lesions (9.05%) diagnosed as lacunes with T1- and T2-weighted imaging were demonstrated as microbleeds with T2*-weighted gradient-echo imaging. Lacunes, leukoaraiosis as a hypertensive change on MRI had statistically significant correlation with the presence of microbleeds. T2*-weighted gradient-echo imaging should be included in the imaging protocol for cerebrovascular disease, because T1- and T2-weighted imaging recognizing some of the microbleeds as lacunar infarction. (author)

  4. Arctic Ground Squirrels Limit Bone Loss during the Prolonged Physical Inactivity Associated with Hibernation.

    Science.gov (United States)

    Wojda, Samantha J; Gridley, Richard A; McGee-Lawrence, Meghan E; Drummer, Thomas D; Hess, Ann; Kohl, Franziska; Barnes, Brian M; Donahue, Seth W

    2016-01-01

    Prolonged disuse (e.g., physical inactivity) typically results in increased bone porosity, decreased mineral density, and decreased bone strength, leading to increased fracture risk in many mammals. However, bears, marmots, and two species of ground squirrels have been shown to preserve macrostructural bone properties and bone strength during long seasons of hibernation while they remain mostly inactive. Some small hibernators (e.g., 13-lined ground squirrels) show microstructural bone loss (i.e., osteocytic osteolysis) during hibernation, which is not seen in larger hibernators (e.g., bears and marmots). Arctic ground squirrels (Urocitellus parryii) are intermediate in size between 13-lined ground squirrels and marmots and are perhaps the most extreme rodent hibernator, hibernating for up to 8 mo annually with body temperatures below freezing. The goal of this study was to quantify the effects of hibernation and inactivity on cortical and trabecular bone properties in arctic ground squirrels. Cortical bone geometrical properties (i.e., thickness, cross-sectional area, and moment of inertia) at the midshaft of the femur were not different in animals sampled over the hibernation and active seasons. Femoral ultimate stress tended to be lower in hibernators than in summer animals, but toughness was not affected by hibernation. The area of osteocyte lacunae was not different between active and hibernating animals. There was an increase in osteocytic lacunar porosity in the hibernation group due to increased lacunar density. Trabecular bone volume fraction in the proximal tibia was unexpectedly greater in the hibernation group than in the active group. This study shows that, similar to other hibernators, arctic ground squirrels are able to preserve many bone properties during hibernation despite being physically inactive for up to 8 mo. PMID:27082526

  5. Danish Rural Eye Study

    DEFF Research Database (Denmark)

    Høeg, Tracy Beth; Ellervik, Christina; Buch, Helena;

    2016-01-01

    PURPOSE: To examine the frequency and causes of visual impairment (VI) in a select population of Danish adults. METHODS: A total of 3843 adults aged 20-94 years from the Danish General Suburban Population Study (GESUS) were included in the population-based, cross-sectional ophthalmological study......, Danish Rural Eye Study (DRES). All DRES participants received a comprehensive general health examination preceding their eye examination, including measurement of best-corrected visual acuity (BCVA) for each eye, bilateral 45° retinal fundus photographs and further ophthalmological examination where...... indicated. RESULTS: Overall, 3826 of 3843 participants (99.6%) had bilateral visual acuity measurements. The overall frequency of VI (BCVA

  6. Entrepreneurship and Process Studies

    DEFF Research Database (Denmark)

    Hjorth, Daniel; Holt, Robin; Steyaert, Chris

    2015-01-01

    Process studies put movement, change and flow first; to study processually is to consider the world as restless, something underway, becoming and perishing, without end. To understand firms processually is to accept but also – and this is harder perhaps – to absorb this fluidity, to treat...... and potential of processual approaches to studying, researching and practising entrepreneurship. The articles in the issue attest to an increasing sensitivity to processual thinking. We argue that appreciating entrepreneurial phenomena processually opens up the field to an understanding of entrepreneurship...

  7. Gold induced apoptsis study

    DEFF Research Database (Denmark)

    Laustsen, Christoffer

    2008-01-01

    in silico methods are here proposed for apoptosis studies and for AMG studies.   Methods   MR - heating of high concentration micrometer gold and low concentration nano gold.   CSLM of ethidum bromide stained cell lines, with and witout gold and automated image processing.   AMG gold uptake study...... the low energy radio frequencies. If the method is demonstrated to be feasible, next step is testing in cell line trials.   Confocal microscopy experiments on cells are very hard to do reliable and reproducible statistic on, due to the fact that that it’s user counting which makes the data. Automatic...

  8. American Studies in Romania

    Directory of Open Access Journals (Sweden)

    Ioana Luca

    2006-01-01

    Full Text Available American Studies at the University of BucharestThe idea of teaching American Studies and founding a program in American Studies was first voiced in the long meetings of faculty and students held at the University of Bucharest soon after the collapse of the communist regime. The proposal was one of many that reflected the spirit of reform and hope for radical changes at the outset of Romania’s transition to democracy. The absence of institutional structures other than English departments and t...

  9. Building Transdisciplinary Environmental Studies

    DEFF Research Database (Denmark)

    Holm, Jesper

    department (Dept. of Environment, Technology and Social Studies, Roskilde University), and has originally in another version been presented in the book “Miljøregulering - tværvidenskabelige studier (Environmental Regulation. Interdisciplinary Studies)” (Holm, Kjærgård & Pedersen eds. 1997, in Danish) written......We will in this paper approach the challenge of building integrated environmental studies by presenting a crude frame of analysis which take into account both the physical aspects and the social-discursive articulations of environmental problems. This framework partly mirrors the approach of our...

  10. Pavement Subgrade Performance Study

    DEFF Research Database (Denmark)

    Zhang, Wei; Ullidtz, Per; Macdonald, Robin

    1998-01-01

    The report describes the second test in the Danish Road Testing Machine (RTM) under the International Pavement Subgrade Performance Study. Pavement response was measured in different layers, and compared to different theroretical values. Performance in terms of plastic strains, rutting...

  11. Thyroid function study

    International Nuclear Information System (INIS)

    A short revision of thyroid physiology is done. The radioisotopes of common use in thyroid investigation and the choice of the most appropriated ones are discussed. A table showing radioisotopes frequently used in this study, with their main characteristics is presented. Among several isotopic assays in thyroid propaedeutics, those that refer to the function study, topographic studies and tests 'in vitro' are pointed out. Exploration methods 'in vivo' are treated, such as: thyroid uptake; urinary excretion; thyroid scintigraphy, with scintigraphic imagings; stimulation test by TSH; suppression test; pbi; clearance test with perchlorate; iodine deficiency test and thyroid study with technetium. 'In vitro' proofs like triiodothyronine (T3) and thyroxine (T4) assays, as well as free thyroxine index, are treated. At last, the therapeutics by Iodine 131 is commented and emphasis is given to its application on the treatment of hyperthyroidism and thyroid carcinoma

  12. Sleep studies (image)

    Science.gov (United States)

    During a sleep study the sleep cycles and stages of sleep are monitored. Electrodes are placed to monitor continuous recordings of brain waves, electrical activity of muscles, eye movement, respiratory ...

  13. Comparative Packaging Study

    Science.gov (United States)

    Perchonok, Michele; Antonini, David

    2008-01-01

    This viewgraph presentation describes a comparative packaging study for use on long duration space missions. The topics include: 1) Purpose; 2) Deliverables; 3) Food Sample Selection; 4) Experimental Design Matrix; 5) Permeation Rate Comparison; and 6) Packaging Material Information.

  14. Accelerator research studies

    International Nuclear Information System (INIS)

    The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under contract number AC05-85ER40216-8, is currently in the third year of its three-year funding cycle. This Renewal Proposal requests DOE support for the next three-year period from June 1, 1991 to May 31, 1994. It documents the progress made during the past year and outlines the proposed research program for the next three years. The program consisted of the following three tasks: Task A, ''Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams,'' Task B, ''Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams,'' Task C, ''Study of a Gyroklystron High-Power Microwave Source for Linear Colliders.'' These tasks will be discussed in this paper

  15. Exploratory studies, 1988

    International Nuclear Information System (INIS)

    This report discusses the following topics: accelerator physics for the ALS; SSC support; machine investigations; mathematical techniques in particle dynamics; APIARY: B-factory studies; and two-beam accelerators and bright electron sources

  16. Accelerator research studies

    International Nuclear Information System (INIS)

    The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER40642, is currently in the first year of a three-year funding cycle. The program consists of the following three tasks: TASK A, Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams, TASK B, Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams; TASK C, Study of a Gyroklystron High-power Microwave Source for Linear Colliders. In this report we document the progress that has been made during the past year for each of the three tasks

  17. Innovation and Entrepreneurship Studies

    DEFF Research Database (Denmark)

    Landström, Hans; Åström, Fredrik; Harirchi, Gouya

    2015-01-01

    As we have moved towards a more knowledge intensive society, innovation and industrial dynamics have grown in importance over the last 40-50 years. We are frequently using concepts such as innovation and entrepreneurship, and the way we perceive and define these concepts will to a high extent...... and entrepreneurship. This study we elaborate on the question: Can innovation and entrepreneurship be seen as one or two fields of research? We will elaborate on this issue by comparing the core works in innovation and entrepreneurship studies respectively, as identified by Fagerberg et al. (Research Policy 41...... innovation and entrepreneurship studies can be considered as two fields or parts of a single broader scientific field, sharing and contributing to the same knowledge base? The studies by Fagerberg et al. and Landström et al. are based on two unique databases consisting of all references in twelve “state...

  18. The Black Studies Boondoggle

    Science.gov (United States)

    Long, Richard A.

    1970-01-01

    Indicates tendencies dangerous to the basic purpose of Black Studies, and identifies four external challeges--imperialism, paternalism, nihilism, and materialism. An internal challenge is considered to be the use of European and Establishment constructs to analyze black reality. (DM)

  19. Progress in Aridification Studies

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ A national key project entitled "Predictive study of aridification in northern China in association with life-supporting environment changes" has recently passed the appraisal of a panel organized by the Ministry of Science & Technology in Beijing.

  20. Upper Kenai Corridor Study

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Upper Kenai Corridor study describes and evaluates the Upper Kenai River and the land which embraces it. It also places the river corridor in its regional...

  1. Mobile OS Comparative Study

    OpenAIRE

    Joseph, Jyothy; K, Shinto Kurian

    2013-01-01

    In the fast growing mobile revolutionary era, many operating systems are playing vital role in present market. This study is intending to identify the apt and secure mobile based on mobile operating systems capability and user requirements.

  2. PPB | Study Team

    Science.gov (United States)

    The Pleuropulmonary Blastoma (PPB) DICER1 Syndrome Study team is made up of researchers from the National Cancer Institute, Children¹s National Medical Center, the International Pleuropulmonary Blastoma Registry, and Washington University in St. Louis.

  3. Schoolground Soil Studies.

    Science.gov (United States)

    Doyle, Charles

    1978-01-01

    Outlined are simple activities for studying soil, which can be conducted in the schoolyard. Concepts include soil profiles, topsoil, soil sizes, making soil, erosion, slope, and water absorption. (SJL)

  4. Accelerator research studies

    International Nuclear Information System (INIS)

    The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER40642, is currently in the second year of a three-year funding cycle. The program consists of the following three tasks: TASK A, ''Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams,'' (P.I., M. Reiser); TASK B, ''Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams,'' (Co-P.I.'s, W.W. Destler, M. Reiser, M.J. Rhee, and C.D. Striffler); TASK C, ''Study of a Gyroklystron High-Power Microwave Source for Linear Colliders,'' (Co-P.I.'s, V.L. Granatstein, W. Lawson, M. Reiser, and C.D. Striffler). In this report we document the progress that has been made during the past year for each of the three tasks

  5. The Study of Matter.

    Science.gov (United States)

    Campbell, Peter

    2000-01-01

    Reviews the booklet "The Study of Matter" produced by the Institute of Physics as part of their Shaping the Future series. This booklet is designed for teachers of chemistry, physics, design and technology, and biology. (Author/CCM)

  6. Accelerator research studies

    International Nuclear Information System (INIS)

    This progress report for the Accelerator Research Studies program at the University of Maryland covers the second year (June 1, 1989 to May 31, 1990) of the current three-year contract period from June 1, 1988 to May 31, 1991, funded by the Department of Energy under Contract No. AC05-85ER40216. The research program is divided into three separate tasks, as follows: the study of Transport and Longitudinal Compression of Intense, High-Brightness Beams; the study of Collective Ion Acceleration by Intense Electron Beams and Pulse-Powered Plasma Focus; the study of Microwave Sources and Parameter Scaling for High-Frequency Linacs. This report consists of three sections in which the progress for each task is documented separately. An introduction and synopsis is presented at the beginning of the progress report for each task

  7. Chamberino Floodplain Management Study

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The Dona Ana County Flood Commission requested the United States Department of Agriculture's Natural Resources Conservation Service to conduct a study of the...

  8. Techno-economic Study

    DEFF Research Database (Denmark)

    Sigurdsson, Halldór Matthias; Point, J.C.; Million, P.

    A techno-economic model for analysing and comparing broadband deployment strategies has been established. The resulting simulation model can compare Capital Expenditure (CAPEX) of dominating broadband technologies in different types of demographic areas. The study reveals the competitiveness and...

  9. Exploratory studies, 1988

    Energy Technology Data Exchange (ETDEWEB)

    1989-05-01

    This report discusses the following topics: accelerator physics for the ALS; SSC support; machine investigations; mathematical techniques in particle dynamics; APIARY: B-factory studies; and two-beam accelerators and bright electron sources.

  10. Prolactinomas: clinical studies

    OpenAIRE

    Kars, Marleen

    2008-01-01

    Prolactinoma are treated with dopamine agonists, which are effective in reducing prolactin and tumor size. Studies reporting clinical and radiological outcome are scarce. The study described in chapter 2, assesses long-term outcome in patients treated with dopamine agonists for macroprolactinoma. An increased risk of cardiac valve disease has been reported in patients treated with cabergoline for Parkinson’s disease. Stimulation of serotonin receptors on cardiac valves by dopamine agonists re...

  11. Thermoluminescence studies in geology

    International Nuclear Information System (INIS)

    Even though the phenomenon of thermoluminescence is well studied, particularly over last 3 decades, its potentialities in the field of geology have not been adequately evaluated. In this report several useful applications of TL in mineralogy, petrogenesis, stratigraphy, tectonics, ore-prospecting and other branches have been identified with particular emphasis to the Indian scene. Important areas in the country that may provide the basic material for such studies are indicated at the end along with brief geological or mineralogical accounts. (auth.)

  12. Zambia country study

    Energy Technology Data Exchange (ETDEWEB)

    1999-09-01

    The Zambia Country Study, which was part of the Danida-funded project Climate Change Mitigation in Southern Africa: Phase 2, aimed at methodological development, national mitigation analysis and institutional capacity building in Zambia. The study comprised the following five elements: Comprehensive evaluation of national social and economic development framework for climate change; Baseline scenario(s) projection(s); Mitigation scenario(s) projection(s); Macro-economic assessment; Implementation Issues. (au) 17 refs.

  13. Waarom Jesus-studies?

    OpenAIRE

    P.A. Geyser

    2000-01-01

    Why Jesus studies? Present-day historical Jesus studies are the epistemological product of what has become known as the New Historicism. The aim of the article is to emphasize two aspects of the New Historicism as epistemological approach. The one aspect focuses on the profitability of this endeavour and the other on the historical nature of the New Historicism. As far as profitability is concerned, the social standing and identity of the researcher are emphasized. Among otherthings, the soci...

  14. Construction 'Work Study'

    OpenAIRE

    Kumaraswamy, Mohan

    2002-01-01

    One element of the CIVCAL project Web-based resources containing images, tables, texts and associated data relating to approaches to 'Construction Work Study'. This is defined as 'A management service based on those techniques, particularly Method Study and Work Measurement, which are used in examining human work in all its contexts, and which lead to systematic investigation of all the resources and factors affecting the efficiency and economy of the situation being reviewed, in order ...

  15. Vitrification melter study

    International Nuclear Information System (INIS)

    This report presents the results of a study performed to identify the most promising vitrification melter technologies that the Department of Energy (EM-50) might pursue with available funding. The primary focus was on plasma arc systems and graphite arc melters. The study was also intended to assist EM-50 in evaluating competing technologies, formulating effective technology strategy, developing focused technology development projects, and directing the work of contractors involved in vitrification melter development

  16. Cerebral perfution studies

    International Nuclear Information System (INIS)

    For detecting in precocious form a coronary disease is necessary to aply a diagnostic techniques. The main considerations to be indicated in the present work are: physiological considerations, myocardial perfusion studies with radiotracers such as Talio 201, 99mTc, MIBI, 99mTc-Teboroxima, 99mTc-Fosfinas, instrumentation for obtain good images, proceedings protocols, studies interpretation, standards, SPECT, anomalies standards, coronary diseases

  17. Workshop I: Gender Studies

    Science.gov (United States)

    Hennessey, Eden; Kurup, Anitha; Meza-Montes, Lilia; Shastri, Prajval; Ghose, Shohini

    2015-12-01

    Participants in the Gender Studies workshop of the 5th IUPAP International Conference on Women in Physics discussed the gender question in science practice from a policy perspective, informed by investigations from the social science disciplines. The workshop's three sessions—"Equity and Education: Examining Gender Stigma in Science," "A Comparative Study of Women Scientists and Engineers: Experiences in India and the US," and "Toward Gender Equity Through Policy: Characterizing the Social Impact of Interventions—are summarized, and the resulting recommendations presented.

  18. Rotordynamic Stability Case Studies

    OpenAIRE

    Choudhury Pranabesh

    2004-01-01

    In this article case studies are presented involving rotordynamic instability of modern high-speed turbomachinery relating the field data to analytical methods. The studies include oil seal related field problems, instability caused by aerodynamic cross-coupling in high-pressure, high-speed compressors, and hydrodynamic bearing instability resulting in subsynchronous vibration of a high-speed turbocharger. It has been shown that the analytical tools not only help in problem diagnostics, bu...

  19. Tanzania country study

    International Nuclear Information System (INIS)

    An objective of this study is to analyse the role of the land use sectors of Tanzania (especially forestry) on mitigation of greenhouse gases. Specific emphasis is placed on the relationship between forestry and energy supply from biomass. This is a follow up study on an earlier effort which worked on mitigation options in the country without an in-depth analysis of the forestry and land use sectors. (au)

  20. The CIMESTRA study

    DEFF Research Database (Denmark)

    Hetland, Merete L; Hørslev-Petersen, Kim

    2012-01-01

    Treatment of early rheumatoid arthritis (RA) include aiming at disease control with early use of methotrexate (MTX) in monotherapy or in combination with glucocorticoids or other disease-modifying drugs (DMARDs). The CIMESTRA study applied an aggressive treatment with DMARD and intra......-articular injections of glucocorticoids (i.a. GC) to control disease activity. This paper reviews the results of the five years' study....

  1. The CIMESTRA study

    DEFF Research Database (Denmark)

    Hetland, Merete L; Hørslev-Petersen, Kim

    2013-01-01

    Treatment of early rheumatoid arthritis (RA) include aiming at disease control with early use of methotrexate (MTX) in monotherapy or in combination with glucocorticoids or other disease-modifying drugs (DMARDs). The CIMESTRA study applied an aggressive treatment with DMARD and intra......-articular injections of glucocorticoids (i.a. GC) to control disease activity. This paper reviews the results of the five years' study....

  2. Tanzania country study

    Energy Technology Data Exchange (ETDEWEB)

    Meena, H.E. [Centre for Energy, Environment, Science and Technology, Dar es Salaam (Tanzania, United Republic of)

    1998-10-01

    An objective of this study is to analyse the role of the land use sectors of Tanzania (especially forestry) on mitigation of greenhouse gases. Specific emphasis is placed on the relationship between forestry and energy supply from biomass. This is a follow up study on an earlier effort which worked on mitigation options in the country without an in-depth analysis of the forestry and land use sectors. (au)

  3. Constellation Commodities Studies Summary

    Science.gov (United States)

    Dirschka, Eric

    2011-01-01

    Constellation program was NASA's long-term program for space exploration. The goal of the commodities studies was to solicit industry expertise in production, storage, and transportation required for future use and to improve efficiency and life cycle cost over legacy methods. Objectives were to consolidate KSC, CCAFS and other requirements; extract available industry expertise; identify commercial opportunities; and establish synergy with State of Florida partnerships. Study results are reviewed.

  4. American Studies in Finland

    OpenAIRE

    Jopi Nyman

    2005-01-01

    Since its establishment in 1996, the Finnish American Studies Association has sought to promote the field of American Studies in Finland by organizing conferences, events and by increasing networking amongst its scattered membership (ca. 35) working at various universities and other higher education institutions. The current President of the Association is Dr Jopi Nyman (University of Joensuu) and its Secretary is Dr Ari Helo (University of Helsinki). While currently only the University of He...

  5. Impact studies at Winfrith

    International Nuclear Information System (INIS)

    Analytical and experimental studies of subsonic impacts on nuclear reactor plant structures have been in progress at Winfrith since 1977. These studies have examined the behaviour of concrete and metal structures under the impact of missiles typifying those derived either from the plant itself or from external sources, such as crashing aircraft. During 1986 the Winfrith programme was expanded to include studies of the behaviour of radioactive materials transport containers under impact conditions. This report initially describes the experimental facilities available for impact studies at Winfrith. These include both compressed air guns, capable of delivering payloads of up to 65 kg at sonic velocity or payloads up to 2 tonnes at speeds up to 45 ms-1, and drop test facilities for impact testing of models, up to full-scale radioactive materials transport flasks, at relatively low speeds. Supporting facilities include a small concrete manufacturing laboratory to produce concrete targets. Assessments of the resistance of concrete or metal structures to impact damage are performed using empirical or semi-empirical correlations, derived from data obtained in well-characterised experiments, or using structural dynamics finite element codes. The codes used by the analysts and the computing facilities available for impact analysis work are described. Finally the current programme of impact studies is reviewed, recent progress is summarised and future plans outlined. (author)

  6. Laboratory microfusion capability study

    International Nuclear Information System (INIS)

    The purpose of this study is to elucidate the issues involved in developing a Laboratory Microfusion Capability (LMC) which is the major objective of the Inertial Confinement Fusion (ICF) program within the purview of the Department of Energy's Defense Programs. The study was initiated to support a number of DOE management needs: to provide insight for the evolution of the ICF program; to afford guidance to the ICF laboratories in planning their research and development programs; to inform Congress and others of the details and implications of the LMC; to identify criteria for selection of a concept for the Laboratory Microfusion Facility and to develop a coordinated plan for the realization of an LMC. As originally proposed, the LMC study was divided into two phases. The first phase identifies the purpose and potential utility of the LMC, the regime of its performance parameters, driver independent design issues and requirements, its development goals and requirements, and associated technical, management, staffing, environmental, and other developmental and operational issues. The second phase addresses driver-dependent issues such as specific design, range of performance capabilities, and cost. The study includes four driver options; the neodymium-glass solid state laser, the krypton fluoride excimer gas laser, the light-ion accelerator, and the heavy-ion induction linear accelerator. The results of the Phase II study are described in the present report

  7. Photovoltaics information user study

    Energy Technology Data Exchange (ETDEWEB)

    Belew, W.W.; Wood, B.L.; Marie, T.L.; Reinhardt, C.L.

    1980-10-01

    The results of a series of telephone interviews with groups of users of information on photovoltaics (PV) are described. These results, part of a larger study on many different solar technologies, identify types of information each group needed and the best ways to get information to each group. The report is 1 of 10 discussing study results. The overall study provides baseline data about information needs in the solar community. It covers these technological areas: photovoltaics, passive solar heating and cooling, active solar heating and cooling, biomass energy, solar thermal electric power, solar industrial and agricultural process heat, wind energy, ocean energy, and advanced energy storage. An earlier study identified the information user groups in the solar community and the priority (to accelerate solar energy commercialization) of getting information to each group. In the current study only high-priority groups were examined. Results from seven PV groups respondents are analyzed in this report: DOE-Funded Researchers, Non-DOE-Funded Researchers, Researchers Working for Manufacturers, Representatives of Other Manufacturers, Representatives of Utilities, Electric Power Engineers, and Educators.

  8. Analysis on risk factors of short-term poor outcome among different subtypes of acute cerebral infarction

    International Nuclear Information System (INIS)

    Objective: to investigate the risk factors of short-term poor outcome among patients suffering from acute cerebral infarction who had different subtypes of cerebral infarction. Methods: A total of 3231 acute cerebral infarction patients were included in the present study. Data on demographic characteristics, life style, risk factors, history of cardiovascular disease, admission blood pressure, and clinical outcome at discharge were collected for all participants. Poor outcome was defined as NIHSS ≥10 at discharge or death occurring during hospitalization. The association between poor outcome of cerebral infarction and risk factors was analyzed by using multiple logistic models. Results: Incidence rate of poor outcome is the highest in the patients with cerebral embolism, next in patients with cerebral thrombosis and the lowest in patients with lacunar infarction. Cerebral thrombosis was positively associated with smoking (OR: 1.228; 95% CI: 1.013∼1.637), dyslipidemia (OR: 1.264; 95% CI: 1.081∼1.478), and a history of diabetes mellitus (OR: 1.371; 95% CI: 1.075∼1.747); cerebral embolism was positively associated with a history of atrial fibrillation (OR: 3.131; 95% CI: 1.206∼8.128) and a history of rheumatic heart disease (OR: 5.601; 95% CI: 1.561∼20.091); lacunar infarction is positively associated with alcohol consumption, (OR: 1.428; 95% CI: 1.063∼1.919). Conclusion: The incidence rate of poor outcome is the highest in the patients with cerebral embolism among three subtypes of cerebral infarction, there are different risk factors of poor outcome for three subtypes of cerebral infarction. (authors)

  9. Diversity and abundance of invertebrate epifaunal assemblages associated with gorgonians are driven by colony attributes

    KAUST Repository

    Curdia, Joao

    2015-03-20

    The present study aimed to explicitly quantify the link between the attributes of shallow-water gorgonian colonies (Octocorallia: Alcyonacea) and the ecological patterns of associated non-colonial epifaunal invertebrates. Based on multiple regression analysis, we tested the contribution of several attributes (colony height, width, and area, fractal dimension as a measure of colony complexity, lacunarity as a measure of the heterogeneity, and “colonial” epibiont cover) to abundance and taxonomic richness of associated assemblages. The results highlight the variation in the response of epifaunal assemblages to the gorgonian colony characteristics. The nature and intensity of the relationships were gorgonian species-dependent and varied from one taxonomic group to another. For both gorgonian species analyzed, the strongest predictor of species richness and abundance of the epifaunal assemblages was “colonial” epibiont cover, possibly due to a trophic effect (direct or indirect enhancement of food availability) combined with the surface available for colonization (species–area effect). Although structural complexity is usually indicated as the main driver for rich and abundant coral-associated assemblages, no significant relationship was observed between fractal dimension and the community descriptors; lacunarity, which reflects the sizes of the inter-branch spaces, was only linked to taxonomic richness in the assemblages associated with Leptogorgia lusitanica. The validity of the paradigm that structural complexity enhances biodiversity may be scale-dependent. In the case of gorgonians, the effect of complexity at the “garden” level may be more relevant than at the individual colony level. This reinforces the need for the conservation of gorgonian aggregation areas as a whole in order to preserve host diversity and size structure. © 2015 Springer-Verlag Berlin Heidelberg

  10. The Effects of Stroke Type, Locus, and Extent on Long-Term Outcome of Gait Rehabilitation: The LEAPS Experience.

    Science.gov (United States)

    Nadeau, Stephen E; Dobkin, Bruce; Wu, Samuel S; Pei, Qinglin; Duncan, Pamela W

    2016-08-01

    Background Paresis in stroke is largely a result of damage to descending corticospinal and corticobulbar pathways. Recovery of paresis predominantly reflects the impact on the neural consequences of this white matter lesion by reactive neuroplasticity (mechanisms involved in spontaneous recovery) and experience-dependent neuroplasticity, driven by therapy and daily experience. However, both theoretical considerations and empirical data suggest that type of stroke (large vessel distribution/lacunar infarction, hemorrhage), locus and extent of infarction (basal ganglia, right-hemisphere cerebral cortex), and the presence of leukoaraiosis or prior stroke might influence long-term recovery of walking ability. In this secondary analysis based on the 408 participants in the Locomotor Experience Applied Post-Stroke (LEAPS) study database, we seek to address these possibilities. Methods Lesion type, locus, and extent were characterized by the 2 neurologists in the LEAPS trial on the basis of clinical computed tomography and magnetic resonance imaging scans. A series of regression models was used to test our hypotheses regarding the effects of lesion type, locus, extent, and laterality on 2- to 12-month change in gait speed, controlling for baseline gait speed, age, and Berg Balance Scale score. Results Gait speed change at 1 year was significantly reduced in participants with basal ganglia involvement and prior stroke. There was a trend toward reduction of gait speed change in participants with lacunar infarctions. The presence of right-hemisphere cortical involvement had no significant impact on outcome. Conclusions Type, locus, and extent of lesion, and the loss of substrate for neuroplastic effect as a result of prior stroke may affect long-term outcome of rehabilitation of hemiparetic gait. PMID:26498434

  11. Diversity and abundance of invertebrate epifaunal assemblages associated with gorgonians are driven by colony attributes

    Science.gov (United States)

    Cúrdia, João; Carvalho, Susana; Pereira, Fábio; Guerra-García, José Manuel; Santos, Miguel N.; Cunha, Marina R.

    2015-06-01

    The present study aimed to explicitly quantify the link between the attributes of shallow-water gorgonian colonies (Octocorallia: Alcyonacea) and the ecological patterns of associated non-colonial epifaunal invertebrates. Based on multiple regression analysis, we tested the contribution of several attributes (colony height, width, and area, fractal dimension as a measure of colony complexity, lacunarity as a measure of the heterogeneity, and "colonial" epibiont cover) to abundance and taxonomic richness of associated assemblages. The results highlight the variation in the response of epifaunal assemblages to the gorgonian colony characteristics. The nature and intensity of the relationships were gorgonian species-dependent and varied from one taxonomic group to another. For both gorgonian species analyzed, the strongest predictor of species richness and abundance of the epifaunal assemblages was "colonial" epibiont cover, possibly due to a trophic effect (direct or indirect enhancement of food availability) combined with the surface available for colonization (species-area effect). Although structural complexity is usually indicated as the main driver for rich and abundant coral-associated assemblages, no significant relationship was observed between fractal dimension and the community descriptors; lacunarity, which reflects the sizes of the inter-branch spaces, was only linked to taxonomic richness in the assemblages associated with Leptogorgia lusitanica. The validity of the paradigm that structural complexity enhances biodiversity may be scale-dependent. In the case of gorgonians, the effect of complexity at the "garden" level may be more relevant than at the individual colony level. This reinforces the need for the conservation of gorgonian aggregation areas as a whole in order to preserve host diversity and size structure.

  12. Fractal dimension of trabecular bone: comparison of three histomorphometric computed techniques for measuring the architectural two-dimensional complexity.

    Science.gov (United States)

    Chappard, D; Legrand, E; Haettich, B; Chalès, G; Auvinet, B; Eschard, J P; Hamelin, J P; Baslé, M F; Audran, M

    2001-11-01

    Trabecular bone has been reported as having two-dimensional (2-D) fractal characteristics at the histological level, a finding correlated with biomechanical properties. However, several fractal dimensions (D) are known and computational ways to obtain them vary considerably. This study compared three algorithms on the same series of bone biopsies, to obtain the Kolmogorov, Minkowski-Bouligand, and mass-radius fractal dimensions. The relationships with histomorphometric descriptors of the 2-D trabecular architecture were investigated. Bone biopsies were obtained from 148 osteoporotic male patients. Bone volume (BV/TV), trabecular characteristics (Tb.N, Tb.Sp, Tb.Th), strut analysis, star volumes (marrow spaces and trabeculae), inter-connectivity index, and Euler-Poincaré number were computed. The box-counting method was used to obtain the Kolmogorov dimension (D(k)), the dilatation method for the Minkowski-Bouligand dimension (D(MB)), and the sandbox for the mass-radius dimension (D(MR)) and lacunarity (L). Logarithmic relationships were observed between BV/TV and the fractal dimensions. The best correlation was obtained with D(MR) and the lowest with D(MB). Lacunarity was correlated with descriptors of the marrow cavities (ICI, star volume, Tb.Sp). Linear relationships were observed among the three fractal techniques which appeared highly correlated. A cluster analysis of all histomorphometric parameters provided a tree with three groups of descriptors: for trabeculae (Tb.Th, strut); for marrow cavities (Euler, ICI, Tb.Sp, star volume, L); and for the complexity of the network (Tb.N and the three D's). A sole fractal dimension cannot be used instead of the classic 2-D descriptors of architecture; D rather reflects the complexity of branching trabeculae. Computation time is also an important determinant when choosing one of these methods. PMID:11745685

  13. Data Resolution and Scale-dependent Fracture Clustering: Implications for Deformation Mechanisms

    Science.gov (United States)

    Roy, A.; Aydin, A.; Mukerji, T.; Cilona, A.

    2015-12-01

    Fracture spacing data collected from scanlines and wells at various resolutions are commonly analyzed for the purposes of aquifer and reservoir characterization. It has been previously found for a certain set of nested fracture networks with similar fractal dimensions that differences in scale of observation hence, resolution lead to differences in clustering. It remains however, to be established whether differences in resolution of fracture spacing data can lead to significant differences in clustering behavior for a wider range of datasets. Most studies on fracture analysis either consider the cumulative frequency of spacing data without regard to the actual sequence of the spacing values or compute an average spacing that may not delineate clustered fractures. The coefficient of variation parameter, Cv is often used to differentiate between clustered, random, and unclustered fractures in a scanline but does not address the issue of scale-dependent variations. Lacunarity is a parameter that has been previously used for quantifying the scale-dependent clustering of spatial patterns and recently, this technique has also been used for identifying scale-dependent pattern changes from scanline data. The current research illustrates the application of this technique for delineating differences between scale-dependent clustering attributes of data collected at various resolutions along the same scanline. Specifically, data were collected at different resolutions from two outcrop exposures, a cliff-section and pavement, of the Cretaceous turbititic sandstones of the Chatsworth Formation widely exposed in southern California (USA). For each scanline, low resolution aerial photographs and high resolution ground measurements are analyzed for scale-dependent clustering attributes. In terms of scale-dependent lacunarity, higher resolution data show larger values than their respective low-resolution counterparts. It is postulated that lower resolution data captures fracture

  14. Changes to the cell, tissue and architecture levels in cranial suture synostosis reveal a problem of timing in bone development

    Directory of Open Access Journals (Sweden)

    J Regelsberger

    2012-11-01

    Full Text Available Premature fusion of cranial sutures is a common problem with an incidence of 3-5 per 10,000 live births. Despite progress in understanding molecular/genetic factors affecting suture function, the complex process of premature fusion is still poorly understood. In the present study, corresponding excised segments of nine patent and nine prematurely fused sagittal sutures from infants (age range 3-7 months with a special emphasis on their hierarchical structural configuration were compared. Cell, tissue and architecture characteristics were analysed by transmitted and polarised light microscopy, 2D-histomorphometry, backscattered electron microscopy and energy-dispersive-x-ray analyses. Apart from wider sutural gaps, patent sutures showed histologically increased new bone formation compared to reduced new bone formation and osseous edges with a more mature structure in the fused portions of the sutures. This pattern was accompanied by a lower osteocyte lacunar density and a higher number of evenly mineralised osteons, reflecting pronounced lamellar bone characteristics along the prematurely fused sutures. In contrast, increases in osteocyte lacunar number and size accompanied by mineralisation heterogeneity and randomly oriented collagen fibres predominantly signified woven bone characteristics in patent, still growing suture segments. The already established woven-to-lamellar bone transition provides evidence of advanced bone development in synostotic sutures. Since structural and compositional features of prematurely fused sutures did not show signs of pathological/defective ossification processes, this supports the theory of a normal ossification process in suture synostosis – just locally commencing too early. These histomorphological findings may provide the basis for a better understanding of the pathomechanism of craniosynostosis, and for future strategies to predict suture fusion and to determine surgical intervention.

  15. Relationship between the chondrocyte maturation cycle and the endochondral ossification in the diaphyseal and epiphyseal ossification centers.

    Science.gov (United States)

    Pazzaglia, Ugo E; Congiu, Terenzio; Sibilia, Valeria; Pagani, Francesca; Benetti, Anna; Zarattini, Guido

    2016-09-01

    The chondrocyte maturation cycle and endochondral ossification were studied in human, fetal cartilage Anlagen and in postnatal meta-epiphyses. The relationship between the lacunar area, the inter-territorial fibril network variations, and calcium phosphorus nucleation in primary and secondary ossification centers were assessed using light microscopy and scanning electron microscopy (SEM) morphometry. The Anlage topographic, zonal classification was derived from the anatomical nomenclature of the completely developed long bone (diaphysis, metaphyses and epiphyses). A significant increase in the chondrocyte lacunar area was documented in the Anlage of epiphyseal zones 4 and 3 to zone 2 (metaphysis) and zone 1 (diaphysis), with the highest variation from zone 2 to zone 1. An inverse reduction in the intercellular matrix area and matrix interfibrillar empty space was also documented. These findings are consistent with the osmotic passage of free cartilage water from the interfibrillar space into the swelling chondrocytes, which increased the ion concentrations to a critical threshold for mineral precipitation in the matrix. The mineralized cartilage served as a scaffold for osteoblast apposition both in primary and secondary ossification centers and in the metaphyseal growth plate cartilage, though at different periods of bone Anlage development and with distinct patterns for each zone. All developmental processes shared a common initial pathway but progressed at different rates, modes and organization in diaphysis, metaphysis and epiphysis. In the ossification phase the developing vascular supply appeared to play a key role in determining the cortical or trabecular structure of the long bones. J. Morphol. 277:1187-1198, 2016. © 2016 Wiley Periodicals, Inc.

  16. Underground layout tradeoff study

    International Nuclear Information System (INIS)

    This report presents the results of a technical and economic comparative study of four alternative underground layouts for a nuclear waste geologic repository in salt. The four alternatives considered in this study are (1) separate areas for spent fuel (SF) and commercial high-level waste (CHLW); (2) panel alternation, in which SF and CHLW are emplaced in adjacent panels of rooms; (3) room alternation, in which SF and CHLW are emplaced in adjacent rooms within each panel; and (4) intimate mixture, in which SF and CHLW are emplaced in random order within each storage room. The study concludes that (1) cost is not an important factor; (2) the separate-areas and intimate-mixture alternatives appear, technically, to be more desirable than the other alternatives; and (3) the selection between the separate-areas and intimate mixture alternatives depends upon future resolution of site-specific and reprocessing questions. 5 refs., 6 figs., 12 tabs

  17. Seal design alternatives study

    International Nuclear Information System (INIS)

    This report presents the results from a study of various sealing alternatives for the WIPP sealing system. Overall, the sealing system has the purpose of reducing to the extent possible the potential for fluids (either gas or liquid) from entering or leaving the repository. The sealing system is divided into three subsystems: drift and panel seals within the repository horizon, shaft seals in each of the four shafts, and borehole seals. Alternatives to the baseline configuration for the WIPP seal system design included evaluating different geometries and schedules for seal component installations and the use of different materials for seal components. Order-of-magnitude costs for the various alternatives were prepared as part of the study. Firm recommendations are not presented, but the advantages and disadvantages of the alternatives are discussed. Technical information deficiencies are identified and studies are outlined which can provide required information

  18. Danish Rural Eye Study

    DEFF Research Database (Denmark)

    Høeg, Tracy B; Moldow, Birgitte; Ellervik, Christina;

    2015-01-01

    PURPOSE: To determine the prevalence of amblyopia in Denmark before and after the initiation of the Danish national preschool vision screening programme. METHODS: In a population-based cross-sectional study, 3826 participants of the Danish General Suburban Population Study (GESUS) aged 20 years...... and older from a Danish rural municipality received a complete general health examination and an ophthalmological interview and examination. This study included a comprehensive ophthalmologic interview, measurement of best corrected visual acuity (BCVA) in each eye, Hirschberg's test for strabismus and two...... 45-degree retinal fundus photographs of each eye. A complete ophthalmologic examination was performed when indicated. RESULTS: The prevalence of monocular visual impairment (MVI) was 4.26% (95% CI, 3.66-4.95, n = 163). Amblyopia was the most common cause, accounting for 33%. The prevalence...

  19. Waarom Jesus-studies?

    Directory of Open Access Journals (Sweden)

    P. A. Geyser

    2000-01-01

    Full Text Available Why Jesus studies? Present-day historical Jesus studies are the epistemological product of what has become known as the New Historicism. The aim of the article is to emphasize two aspects of the New Historicism as epistemological approach. The one aspect focuses on the profitability of this endeavour and the other on the historical nature of the New Historicism. As far as profitability is concerned, the social standing and identity of the researcher are emphasized. Among otherthings, the social interests of the researcher are taken into account. Concerning the historical nature of this kind of research, a distinction is drawn between the Jesus of history and the Jesus of faith. The aim of the article is to gain clarity on the relationship between the Jesus of history (pre-Easter and the Jesus of faith (post-Easter. J D Crossan's exposition of the reasons for Jesus studies is followed. He distinguishes three reasons: historical, ethical and theological.

  20. Dynamic lung transmission studies

    International Nuclear Information System (INIS)

    The aim of this study was to develop a non-invasive method for determining regional lungvolumes, which could replace bronchospirometry in routine clinical use. Transmission through the thorax of sup(99m)Tc-gammarays is measured by means of a gamma camera on line with a computer. The technique of measurement and data analysis is described and tested in several series of phantom studies. The results proved to be good: the mean difference with the real volumes was -4%. The error varied between -10% and +1. Transmission studies and bronchospirometry are compared in a group of 11 patients and there proved to be a good correspondence between the results of these methods. It is concluded that transmission experiments can determine the vital capacity of both lungs as a whole as accurately as spirometry and allows the measurement of vital capacity for each lung separately with the same accuracy as bronchospirometry. (Auth.)

  1. The Faroese IBD Study

    DEFF Research Database (Denmark)

    Hammer, Turid; Nielsen, Kari R.; Munkholm, Pia;

    2016-01-01

    Background and Aims: Inflammatory bowel diseases [IBDs] include Crohn’s disease [CD], ulcerative colitis [UC], and IBD unclassified [IBDU]. In 2010 and 2011, the ECCO-EpiCom study found the worldwide highest incidence of inflammatory bowel disease [IBD] in the Faroe Islands: 83 per 100 000...... [European Standard Population, ESP]. The present study assessed the long-term time trends in IBD incidence in the Faroese population. Methods: In this population-based study, data were retrieved from the National Hospital of the Faroe Islands and included all incident cases of CD, UC, and IBDU diagnosed...... between July 1960 and July 2014. Patients of all ages were included and diagnoses were defined according to the Copenhagen Diagnostic Criteria. Results: A total of 664 incident IBD patients were diagnosed: 113 with CD, 417 with UC, and 134 with IBDU. Of these, 51 [8%] were diagnosed with paediatric...

  2. Parylene C Aging Studies.

    Energy Technology Data Exchange (ETDEWEB)

    Achyuthan, Komandoor; Sawyer, Patricia Sue.; Mata, Guillermo Adrian; White II, Gregory Von; Bernstein, Robert

    2014-09-01

    Parylene C is used in a device because of its conformable deposition and other advantages. Techniques to study Parylene C aging were developed, and "lessons learned" that could be utilized for future studies are the result of this initial study. Differential Scanning Calorimetry yielded temperature ranges for Parylene C aging as well as post-deposition treatment. Post-deposition techniques are suggested to improve Parylene C performance. Sample preparation was critical to aging regimen. Short-term (%7E40 days) aging experiments with free standing and ceramic-supported Parylene C films highlighted "lessons learned" which stressed further investigations in order to refine sample preparation (film thickness, single sided uniform coating, machine versus laser cutting, annealing time, temperature) and testing issues ("necking") for robust accelerated aging of Parylene C.

  3. Epidemiological studies on syncope

    DEFF Research Database (Denmark)

    Ruwald, Martin Huth

    2013-01-01

    The epidemiology and prognosis of ''fainting'' or syncope has puzzled physicians over the years. Is fainting dangerous? This is a question often asked by the patient--and the answer is ''it depends on a lot of things''. The diverse pathophysiology of syncope and the underlying comorbidites of the...... from smaller studies from different clinical settings with wide differences in patient morbidity. Through the extensive Danish registries we examined the characteristics and prognosis of the patients hospitalized due to syncope in a nationwide study. The aims of the present thesis were to investigate...... thesis demonstrated that the ICD-10 discharge diagnosis could reliably identify a cohort of patients admitted for syncope and that the discharge code carried a high number of unexplained cases despite use of numerous tests. The last studies showed that syncope is a common cause for hospital contact in...

  4. NMR studies of metalloproteins.

    Science.gov (United States)

    Li, Hongyan; Sun, Hongzhe

    2012-01-01

    Metalloproteins represent a large share of the proteomes, with the intrinsic metal ions providing catalytic, regulatory, and structural roles critical to protein functions. Structural characterization of metalloproteins and identification of metal coordination features including numbers and types of ligands and metal-ligand geometry, and mapping the structural and dynamic changes upon metal binding are significant for understanding biological functions of metalloproteins. NMR spectroscopy has long been used as an invaluable tool for structure and dynamic studies of macromolecules. Here we focus on the application of NMR spectroscopy in characterization of metalloproteins, including structural studies and identification of metal coordination spheres by hetero-/homo-nuclear metal NMR spectroscopy. Paramagnetic NMR as well as (13)C directly detected protonless NMR spectroscopy will also be addressed for application to paramagnetic metalloproteins. Moreover, these techniques offer great potential for studies of other non-metal binding macromolecules.

  5. Study of electroweak interactions

    International Nuclear Information System (INIS)

    The experimental study of electroweak interactions at Virginia Tech is multifaceted and consists of three parts. The first consists of analysis of the final states of matter produced in electron-positron annihilations at center-of-mass energies √s = 60 GeV at the TRISTAN collider in Japan (AMY). The second is a sensitive search for rare electroweak processes through a study of μ+ → e+γ at the LAMPF facility at Los Alamos (MEGA). It also includes a precise measurement of the Michel ρ parameter (RHO). The third activity is a R ampersand D detector development and is a precursor to anticipated experiments at proposed Bo meson factories in this country and/or abroad. The physics goals are the study of CP violation in the Bo system and the determination of the values for Kobayashi-Maskawa matrix

  6. Studie-Units

    DEFF Research Database (Denmark)

    Koustrup, Pia

    2004-01-01

    Denne artikel sætter fokus på tilrettelæggelse af klinisk undervisning og læring, hvor et nyere begreb - studie-units er opstået inden for de sidste par år. Studie-unit er en organisationsform, som sygeplejen helt sikkert vil se en del mere til de næste par år frem i tiden. Artiklen inddrager den...... tyske didaktiker og filosof Wolfgang Klafki i diskussionen om indføring af studie-units. Klafki er valgt, fordi han indgående forholder sig til social læring, og finder læring i fællesskab med ligestillede nødvendigt for at dannelsen i et fag skal kunne lykkes...

  7. Study of iron fluorination

    International Nuclear Information System (INIS)

    This report deals with the action of fluorine on iron. Comprehensive descriptions are given of the particular technological methods and of the preparation of the reactants. This fluorination reaction has been investigated over a very broad range of temperature and pressure. A nucleation and growth phenomenon is described. The influence of a pollution of the gas phase by oxygen on the fluorination process is reported. The solid-state reaction between ferric fluoride and iron has been studied by calorimetry and hydrated fluorides βFeF3, 3 H2O and FeF3, H2O have been studied by Moessbauer effect. A special study has been made of the growth of iron deposits by thermal decomposition of gaseous iron fluorides. (author)

  8. Epidemiological studies on syncope

    DEFF Research Database (Denmark)

    Ruwald, Martin Huth

    2013-01-01

    The epidemiology and prognosis of ''fainting'' or syncope has puzzled physicians over the years. Is fainting dangerous? This is a question often asked by the patient--and the answer is ''it depends on a lot of things''. The diverse pathophysiology of syncope and the underlying comorbidites...... from smaller studies from different clinical settings with wide differences in patient morbidity. Through the extensive Danish registries we examined the characteristics and prognosis of the patients hospitalized due to syncope in a nationwide study. The aims of the present thesis were to investigate...... thesis demonstrated that the ICD-10 discharge diagnosis could reliably identify a cohort of patients admitted for syncope and that the discharge code carried a high number of unexplained cases despite use of numerous tests. The last studies showed that syncope is a common cause for hospital contact...

  9. Seal design alternatives study

    Energy Technology Data Exchange (ETDEWEB)

    Van Sambeek, L.L. [RE/SPEC Inc., Rapid City, SD (US); Luo, D.D.; Lin, M.S.; Ostrowski, W.; Oyenuga, D. [Parsons Brinckerhoff Quade & Douglas, Inc., San Francisco, CA (US)

    1993-06-01

    This report presents the results from a study of various sealing alternatives for the WIPP sealing system. Overall, the sealing system has the purpose of reducing to the extent possible the potential for fluids (either gas or liquid) from entering or leaving the repository. The sealing system is divided into three subsystems: drift and panel seals within the repository horizon, shaft seals in each of the four shafts, and borehole seals. Alternatives to the baseline configuration for the WIPP seal system design included evaluating different geometries and schedules for seal component installations and the use of different materials for seal components. Order-of-magnitude costs for the various alternatives were prepared as part of the study. Firm recommendations are not presented, but the advantages and disadvantages of the alternatives are discussed. Technical information deficiencies are identified and studies are outlined which can provide required information.

  10. Rockwell support studies

    International Nuclear Information System (INIS)

    The Rockwell Hanford Operations (RHO) supported ecological studies are designed to clarify ecosystem structure and functioning as pertaining to the management of radioactive waste control areas. To date, emphasis has been placed on characterizing the abiotic and biotic components of these areas, resulting in publication of over 20 PNL documents and several scientific articles pertinent to the 200 Area Waste Management Program. Results are reported from studies on the food habits of ground-dwelling beetles, mule deer, and American Coots inhabiting the areas, and the radiation dose received by rodents inhabiting waste management areas

  11. Case study - Argentina

    International Nuclear Information System (INIS)

    Antecedents and experience of nuclear activities in Argentina; the Atomic Energy Commission (CNEA). First development and research activities. Research reactors and radioisotopes plants. Health physics and safety regulations. - Feasibility studies for the first nuclear power plant. Awarding the first plant CNA I (Atucha I). Relevant data related to the different project stages. Plant performance. - Feasibility study for the second nuclear power plant. Awarding the second plant CNE (Central Nuclear Embalse). Relevant data related to established targets. Differences compared with the first station targets. Local participation. Plant performance. (orig./GL)

  12. Study of estuarine dynamics

    International Nuclear Information System (INIS)

    A case study of a shallow, well mixed fjord illustrates the use of radioactive and an activable tracer. An instantaneous injection of the rare earth lanthanum was used as an activable tracer to determine residence-time and internal recirculation in the fjord system. An instantaneous injection of bromine-82 was used to investigate tae bypass of water from a harbour area through a power plant cooling water system to a partly enclosed basin of the fjord. Instantaneous releases of bromine-82 were further used for short time studies of the primary spread and transport of river water discharged to the inner section of the fjord system. (Author)

  13. CCNA Wireless Study Guide

    CERN Document Server

    Lammle, Todd

    2010-01-01

    A complete guide to the CCNA Wireless exam by leading networking authority Todd Lammle. The CCNA Wireless certification is the most respected entry-level certification in this rapidly growing field. Todd Lammle is the undisputed authority on networking, and this book focuses exclusively on the skills covered in this Cisco certification exam. The CCNA Wireless Study Guide joins the popular Sybex study guide family and helps network administrators advance their careers with a highly desirable certification.: The CCNA Wireless certification is the most respected entry-level wireless certification

  14. Studies in neuroendocrine pharmacology

    Science.gov (United States)

    Maickel, R. P.

    1976-01-01

    The expertise and facilities available within the Medical Sciences Program section on Pharmacology were used along with informational input from various NASA sources to study areas relevant to the manned space effort. Topics discussed include effects of drugs on deprivation-induced fluid consumption, brain biogenic amines, biochemical responses to stressful stimuli, biochemical and behavioral pharmacology of amphetamines, biochemical and pharmacological studies of analogues to biologically active indole compounds, chemical pharmacology: drug metabolism and disposition, toxicology, and chemical methodology. Appendices include a bibliography, and papers submitted for publication or already published.

  15. Studies in Rheoencephalography (REG

    Directory of Open Access Journals (Sweden)

    Michael Bodo

    2010-01-01

    Full Text Available This article presents an overview of rheoencephalography (REG – electrical impedance measurements of the brain – and summarizes past and ongoing research to develop medical applications of REG for neuro-critical care and for primary prevention of stroke and cardiovascular disease. The availability of advanced electronics and computation has opened up the potential for use of REG technology as a noninvasive, continuous and inexpensive brain monitor for military and civilian applications. The clinical background information presented here introduces physiological and clinical environments where REG has potential for use in research and clinical settings. REG studies over the past three decades have involved in vitro and in vivo groups (animal and human, including more than 1500 measurements and related electronic and computational results and practical applications. In vitro studies helped researchers understand the flow/volume relationship between Doppler ultrasound and electrical impedance signals and supported development of REG data processing methods. In animal studies, REG was used to monitor the lower limit of cerebral blood flow (CBF autoregulation (AR using a newly developed algorithm. These animal studies also confirmed correlations between REG and measurements of carotid flow (CF and intracranial pressure (ICP. Human studies confirmed the applicability of REG for detecting cerebrovascular alteration, demonstrating the usefulness of REG in the field of stroke/cardio-vascular disease prevention. In these studies, REG was compared to known stroke risk factors and to results obtained using carotid ultrasound measurements. An intelligent REG system (Cerberus has been developed for primary stroke prevention. In these studies, the biologically relevant variables of the REG signal were pulse amplitude (minimum – maximum distance and duration of the anacrotic (rising portion of the REG pulse wave. The principal limitation of REG for

  16. Regional Studies Program

    International Nuclear Information System (INIS)

    Progress is reported on methodology studies with regard to hydrologic analysis; atmospheric transport; forest growth models; distribution of sensitive species; agricultural analysis; and environmental objectives in energy facility siting. National coal utilization assessment studies are reported with regard to technology characterization; air quality impacts; water resources; regional characterization; forest impacts; coal extraction impacts on sensitive animal species; and health impacts. The following special projects were carried out: water resource aspects of inexhaustible technology deployment; ecological constraints on the rapidly expanded use of coal; and U.S. coal and the global carbon problem

  17. DWPF Welder Parametric Study

    International Nuclear Information System (INIS)

    After being filled with glass, DWPF canistered waste forms will be welded closed using an upset resistance welding process. This final closure weld must be leaktight, and must remain so during extended storage at SRS. As part of the DWPF Startup Test Program, a parametric study (DWPF-WP-24) has been performed to determine a range of welder operating parameters which will produce acceptable welds. The parametric window of acceptable welds defined by this study is 90,000 + 15,000 lb of force, 248,000 + 22,000 amps of current, and 95 + 15 cycles* for the time of application of the current

  18. Reporting of teratology studies.

    Science.gov (United States)

    Barrow, Paul C; Reynaud, Lucie

    2013-01-01

    The regulatory toxicology report is an unusual document that requires a particular skill to write. The report must be clear, accurate, concise, and focused. A clear and direct writing style is required. The end-users of the report will hope to find the information they seek with as little effort as possible. Few, or none, will read the entire document. The author should aim to appease the user by obliging him to read as little text and turn as few pages as possible. This chapter gives tips and guidance on how to present the experimental data and write the narrative text in the final study report for a teratology study.

  19. Studying Reconfigurations of Discourse

    DEFF Research Database (Denmark)

    Lippert, Ingmar

    2014-01-01

    The stability of a discourse is not given but produced. It is achieved in the configuration of the dispositif. The paper approaches dispositif as a practical ongoing assembling of semiotic and material entities. The article presents an assemblage of theories, methods and methodologies that allow...... tracing how heterogeneous entities are (re)(con)figured to achieve performing a discourse's stability. Using mundane office practices that configure the corporate sustainability/carbon discourse as an example, the article spells out how qualitative data analysis, grounded theory and Science and Technology...... Studies approaches can be interwoven to pursue a grounded and generalisable ethnographic study of discourse....

  20. Critical cyberculture studies

    CERN Document Server

    Silver, David; Jones, Steve

    2006-01-01

    Starting in the early 1990s, journalists and scholars began responding to and trying to take account of new technologies and their impact on our lives. By the end of the decade, the full-fledged study of cyberculture had arrived. Today, there exists a large body of critical work on the subject, with cutting-edge studies probing beyond the mere existence of virtual communities and online identities to examine the social, cultural, and economic relationships that take place online. Taking stock of the exciting work that is being done and positing what cyberculture's future might look like, Criti

  1. Study and Move Forward

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Chairman Mao once said: "Good good study, day day up", which can be roughly deciphered as 'study hard,keep improving'. Chinese people still remember his advice, even in the days of market-oriented reform. Today, one of the utmost urgent tasks for Chinese students is to master the English language. Chinese students start learning English from the kindergarten and English testing is normally a must for most universities. With the Olympic Games coming to Beijing in 2008, the central government has another reason to call its people to master the most popular tongue on our planet.

  2. DWPF Welder Parametric Study

    Energy Technology Data Exchange (ETDEWEB)

    Plodinec, M.J.

    1998-11-20

    After being filled with glass, DWPF canistered waste forms will be welded closed using an upset resistance welding process. This final closure weld must be leaktight, and must remain so during extended storage at SRS. As part of the DWPF Startup Test Program, a parametric study (DWPF-WP-24) has been performed to determine a range of welder operating parameters which will produce acceptable welds. The parametric window of acceptable welds defined by this study is 90,000 + 15,000 lb of force, 248,000 + 22,000 amps of current, and 95 + 15 cycles* for the time of application of the current.

  3. Morphing Terminology Study

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Stuart J.; Brockman, Fred J.; Hart, Michelle L.; Engel, David W.; Valentine, Nancy B.; Calapristi, Augustin J.

    2010-06-28

    This study investigates methods of automatically identifying and characterizing significant transitions in term usage over time. Within scientific literature, the occurrence of terms reflects the use of technologies and techniques as well as the study of specific species and materials. Transitions in terminology usage may be a result of vocabulary standardization or specialization in which terms are replaced with their shorter form. They may also be a result of new applications, combinations, alternatives, or interests that result in the appearance of new or existing terminology in unexpected contexts.

  4. Studying facility siting

    Energy Technology Data Exchange (ETDEWEB)

    Weber, R.J. [PSRG Consultants Inc. (United States)

    2001-02-01

    The article relates to safety in facility siting and the many factors to be taken into account at an early planning stage. Outline flowcharts for analysing the process for a potential explosion show: Stage 1 -building and hazard identification; Stage 2 -building evaluation and Stage 3 -Risk management. A similar chart relates to analysis for a potential toxic release. A 68-point checklist of factors to be considered in a facility siting study is given. It is pointed out that apart from meeting regulatory requirements, a sound facility siting study can lead to more effective use of resources.

  5. WELL PURGING STUDY

    Science.gov (United States)

    Purging of wells with bailers has been a standard practice in the underground storage tank program as well as other groundwater regulatory programs for many years. Several studies in the Northeast and the West have shown that, under certain circumstances, samples collected witho...

  6. Dimethyl Ether Injection Studies

    DEFF Research Database (Denmark)

    Sorenson, Spencer C.; Glensvig, Michael; Abata, Duane L.

    1998-01-01

    in the same system. As a first attempt to simulate combustion of DME in Diesel engines, the results of the spray studies have been incorporated into a simplified spray combustion model. A turbulent jet structure was adjusted to fit the penetration rates of the observed sprays. The observed spray widths agreed...

  7. Case Studies in Biology.

    Science.gov (United States)

    Zeakes, Samuel J.

    1989-01-01

    A case study writing exercise used in a course on parasitology was found to be a powerful learning experience for students because it involved discipline-based technical writing and terminology, brought the students in as evaluators, applied current learning, caused interaction among all students, and simulated real professional activities. (MSE)

  8. COPEWORK - COPESTRESS Workplace Study

    DEFF Research Database (Denmark)

    Ladegaard, Yun Katrine; Netterstrøm, Bo; Langer, Roy

    2012-01-01

    "COPEWORK – COPESTRESS Workplace Study" er en undersøgelse af hvad der sker på arbejdspladser, når en medarbejder sygemeldes med stress. I undersøgelsen indgik 64 ledere og arbejdsmiljørepræsentanter fra fra 38 danske arbejdspladser. Alle arbejdspladser havde haft minimum én stresssygemeldt medar...

  9. Soil washing treatability study

    International Nuclear Information System (INIS)

    Soil washing was identified as a viable treatment process option for remediating soil at the FEMP Environmental Management Project (FEMP). Little information relative to the specific application and potential effectiveness of the soil washing process exists that applies to the types of soil at the FEMP. To properly evaluate this process option in conjunction with the ongoing FEMP Remedial Investigation/Feasibility Study (RI/FS), a treatability testing program was necessary to provide a foundation for a detailed technical evaluation of the viability of the process. In August 1991, efforts were initiated to develop a work plan and experimental design for investigating the effectiveness of soil washing on FEMP soil. In August 1992, the final Treatability Study Work Plan for Operable Unit 5: Soil Washing (DOE 1992) was issued. This document shall be referenced throughout the remainder of this report as the Treatability Study Work Plan (TSWP). The purpose of this treatability study was to generate data to support initial screening and the detailed analysis of alternatives for the Operable Unit 5 FS

  10. Repository seals requirements study

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-11-03

    The Yucca Mountain Site Characterization Project, managed by the Civilian Radioactive Waste Management System (CRWMS) Management and Operating Contractor (M and O) is conducting investigations to support the Viability Assessment and the License Application for a high-level nuclear waste repository at Yucca Mountain, Nevada. The sealing subsystem is part of the Yucca Mountain Waste Isolation System. The Yucca Mountain Site Characterization Project is currently evaluating the role of the sealing subsystem (shaft, ramp and exploratory borehole seals) in achieving the overall performance objectives for the Waste Isolation System. This report documents the results of those evaluations. This report presents the results of a repository sealing requirements study. Sealing is defined as the permanent closure of the shafts, ramps, and exploratory boreholes. Sealing includes those components that would reduce potential inflows above the repository, or that would divert flow near the repository horizon to allow vertical infiltration to below the repository. Sealing of such features as emplacement drifts was not done in this study because the current capability to calculate fracture flow into the drifts is not sufficiently mature. The objective of the study is to provide water or air flow performance based requirements for shafts, ramps, and exploratory boreholes located near the repository. Recommendations, as appropriate, are provided for developing plans, seals component testing, and other studies relating to sealing.

  11. Acid Rain Study Guide.

    Science.gov (United States)

    Hunger, Carolyn; And Others

    Acid rain is a complex, worldwide environmental problem. This study guide is intended to aid teachers of grades 4-12 to help their students understand what acid rain is, why it is a problem, and what possible solutions exist. The document contains specific sections on: (1) the various terms used in conjunction with acid rain (such as acid…

  12. Solid waste study

    International Nuclear Information System (INIS)

    The purpose of this document is to study the solid waste issues brought about by a Type C Investigation; ''Disposal of Inappropriate Material in the Los Alamos County Landfill'' (May 28, 1993). The study was completed in August 1995 by Coleman Research Corporation, under subcontract number 405810005-Y for Los Alamos National Laboratory (LANL). The study confirmed the issues identified in the Type C investigation, and also ascertained further issues or problems. During the course of this study two incidents involving hazardous waste resulted in the inappropriate disposal of the waste. An accidental spill, on June 8, 1995, at one of Laboratory buildings was not handled correctly, and ended up in the LAC Landfill. Hazardous waste was disposed of in a solid waste container and sent to the Los Alamos County Landfill. An attempt to locate the hazardous waste at the LAC Landfill was not successful. The second incident involving hazardous waste was discovered by the FSS-8, during a random dumpster surveillance. An interim dumpster program managed by FSS-8 discovered hazardous waste and copper chips in the solid waste, on August 9, 1995. The hazardous waste and copper chips would have been transported to the LAC Landfill if the audit team had not brought the problem to the awareness of the facility waste management personnel

  13. Studying health in Greenland

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Mulvad, Gert; Olsen, Jørn

    2003-01-01

    Health research in Greenland has contributed with several findings of interest for the global scientific community and has documented health problems and risk factors of importance for planning the local health care system. The study of how health develops in small, scattered communities during...

  14. Nuclear fuel cycle studies

    International Nuclear Information System (INIS)

    For the metal-matrix encapsulation of radioactive waste, brittle-fracture, leach-rate, and migration studies are being conducted. For fuel reprocessing, annular and centrifugal contactors are being tested and modeled. For the LWBR proof-of-breeding project, the full-scale shear and the prototype dissolver were procured and tested. 5 figures

  15. Steam explosion studies review

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Moon Kyu; Kim, Hee Dong

    1999-03-01

    When a cold liquid is brought into contact with a molten material with a temperature significantly higher than the liquid boiling point, an explosive interaction due to sudden fragmentation of the melt and rapid evaporation of the liquid may take place. This phenomenon is referred to as a steam explosion or vapor explosion. Depending upon the amount of the melt and the liquid involved, the mechanical energy released during a vapor explosion can be large enough to cause serious destruction. In hypothetical severe accidents which involve fuel melt down, subsequent interactions between the molten fuel and coolant may cause steam explosion. This process has been studied by many investigators in an effort to assess the likelihood of containment failure which leads to large scale release of radioactive materials to the environment. In an effort to understand the phenomenology of steam explosion, extensive studies has been performed so far. The report presents both experimental and analytical studies on steam explosion. As for the experimental studies, both small scale tests which involve usually less than 20 g of high temperature melt and medium/large scale tests which more than 1 kg of melt is used are reviewed. For the modelling part of steam explosions, mechanistic modelling as well as thermodynamic modelling is reviewed. (author)

  16. Rockwell support studies

    International Nuclear Information System (INIS)

    Studies performed for the Rockwell Hanford Operations (RHO) were designed to either (1) identify the role of biota in the uptake and transport of radionuclides from low-level waste managemnt areas or (2) design and/or evaluate methods for reducing biological transport of radionuclides away from waste management areas. The completion and publication of documents reporting the results of previous studies was also emphasized this fiscal year. Field studies were designed to characterize insect and plant communities occupying low-level waste management areas and to evaluate pond ecosystem response to herbicide application. Laboratory studies involved the examination of (1) germination response in plant species proposed for surface stabilization on burial grounds, (2) a synthetic polymer matrix as a carrier and delivery system for phytotoxins to act as a barrier to plant root penetration of shallow-land low-level waste burial sites, and (3) factors responsible for differences in radionuclide availability to plants resulting from the chemical equilibration of radionuclides occurring under field conditions

  17. Repository seals requirements study

    International Nuclear Information System (INIS)

    The Yucca Mountain Site Characterization Project, managed by the Civilian Radioactive Waste Management System (CRWMS) Management and Operating Contractor (M and O) is conducting investigations to support the Viability Assessment and the License Application for a high-level nuclear waste repository at Yucca Mountain, Nevada. The sealing subsystem is part of the Yucca Mountain Waste Isolation System. The Yucca Mountain Site Characterization Project is currently evaluating the role of the sealing subsystem (shaft, ramp and exploratory borehole seals) in achieving the overall performance objectives for the Waste Isolation System. This report documents the results of those evaluations. This report presents the results of a repository sealing requirements study. Sealing is defined as the permanent closure of the shafts, ramps, and exploratory boreholes. Sealing includes those components that would reduce potential inflows above the repository, or that would divert flow near the repository horizon to allow vertical infiltration to below the repository. Sealing of such features as emplacement drifts was not done in this study because the current capability to calculate fracture flow into the drifts is not sufficiently mature. The objective of the study is to provide water or air flow performance based requirements for shafts, ramps, and exploratory boreholes located near the repository. Recommendations, as appropriate, are provided for developing plans, seals component testing, and other studies relating to sealing

  18. NGLW RCRA Storage Study

    Energy Technology Data Exchange (ETDEWEB)

    R. J. Waters; R. Ochoa; K. D. Fritz; D. W. Craig

    2000-06-01

    The Idaho Nuclear Technology and Engineering Center (INTEC) at the Idaho National Engineering and Environmental Laboratory contains radioactive liquid waste in underground storage tanks at the INTEC Tank Farm Facility (TFF). INTEC is currently treating the waste by evaporation to reduce the liquid volume for continued storage, and by calcination to reduce and convert the liquid to a dry waste form for long-term storage in calcine bins. Both treatment methods and activities in support of those treatment operations result in Newly Generated Liquid Waste (NGLW) being sent to TFF. The storage tanks in the TFF are underground, contained in concrete vaults with instrumentation, piping, transfer jets, and managed sumps in case of any liquid accumulation in the vault. The configuration of these tanks is such that Resource Conservation and Recovery Act (RCRA) regulations apply. The TFF tanks were assessed several years ago with respect to the RCRA regulations and they were found to be deficient. This study considers the configuration of the current tanks and the RCRA deficiencies identified for each. The study identifies four potential methods and proposes a means of correcting the deficiencies. The cost estimates included in the study account for construction cost; construction methods to minimize work exposure to chemical hazards, radioactive contamination, and ionizing radiation hazards; project logistics; and project schedule. The study also estimates the tank volumes benefit associated with each corrective action to support TFF liquid waste management planning.

  19. Designing satisfaction studies

    DEFF Research Database (Denmark)

    Kristensen, Kai; Eskildsen, Jacob Kjær

    2007-01-01

    In the effect sampling method, presentation of researcher, the intro text, the order of questions in the questionnaire along with the number of categories in the rating scale is tested in relation to the design of satisfaction studies. Based on the analyses specific recommendations for designing...

  20. Study of Tools Interoperability

    NARCIS (Netherlands)

    Krilavičius, T.

    2007-01-01

    Interoperability of tools usually refers to a combination of methods and techniques that address the problem of making a collection of tools to work together. In this study we survey different notions that are used in this context: interoperability, interaction and integration. We point out relation

  1. Environmental Modification: A Study

    Science.gov (United States)

    Grinnell, Richard M., Jr.; Kyte, Nancy S.

    1975-01-01

    This study shows that environmental modification is a surprisingly intricate technique. This may account for its relatively low use and also for its more frequent use by MSW than non-MSW caseworkers. The findings indicate the need for further research on environmental modification. (Author)

  2. Steam explosion studies review

    International Nuclear Information System (INIS)

    When a cold liquid is brought into contact with a molten material with a temperature significantly higher than the liquid boiling point, an explosive interaction due to sudden fragmentation of the melt and rapid evaporation of the liquid may take place. This phenomenon is referred to as a steam explosion or vapor explosion. Depending upon the amount of the melt and the liquid involved, the mechanical energy released during a vapor explosion can be large enough to cause serious destruction. In hypothetical severe accidents which involve fuel melt down, subsequent interactions between the molten fuel and coolant may cause steam explosion. This process has been studied by many investigators in an effort to assess the likelihood of containment failure which leads to large scale release of radioactive materials to the environment. In an effort to understand the phenomenology of steam explosion, extensive studies has been performed so far. The report presents both experimental and analytical studies on steam explosion. As for the experimental studies, both small scale tests which involve usually less than 20 g of high temperature melt and medium/large scale tests which more than 1 kg of melt is used are reviewed. For the modelling part of steam explosions, mechanistic modelling as well as thermodynamic modelling is reviewed. (author)

  3. Social Studies: Grade 8.

    Science.gov (United States)

    Manitoba Dept. of Education, Winnipeg.

    This Manitoba (Canada) curriculum guide for eighth grade social studies students contains suggested teaching strategies and learning activities in four units covering: (1) life during prehistoric and early historic times; (2) ancient civilizations; (3) life in early modern Europe; and (4) life in the modern world. Each unit includes an overview,…

  4. Course Placement Study.

    Science.gov (United States)

    Fredericksen, Marlene; Slark, Julie

    Following the implementation of a matriculation plan at Rancho Santiago College (RSC), a study was conducted to examine the appropriateness of student course placement as assessed by faculty and students and to investigate faculty's perceptions of changes in students' skill level preparation over the past few years. Questionnaires were completed…

  5. Everglades Environmental Study Units.

    Science.gov (United States)

    Florida State Dept. of Education, Tallahassee. Office of Environment Education.

    These environmental study units consist of four modules and a tape-slide presentation on the Everglades National Park. Although not required for completion of the modules, the slide-tape presentation provides a resource for orientation of teachers and parents to camping experience for school children in an environmental education program. The four…

  6. Studying Ancient History.

    Science.gov (United States)

    Barrow, Robin

    1982-01-01

    Defends the value and relevance of the study of ancient history and classics in history curricula. The unique homogeneity of the classical period contributes to its instructional manageability. A year-long, secondary-level course on fifth-century Greece and Rome is described to illustrate effective approaches to teaching ancient history. (AM)

  7. SOFC interface studies

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Bay, Lasse; West, Keld;

    performance and inductive hysteresis phenomena often observed in SOFC kinetic studies (\\ref{TJ01}). Fig.\\,\\ref{cath_laser} shows the YSZ surface developed below a Pt point electrode polarised at -0.10\\, V at $1000^\\circ$C for a period of 85 days. The structural as well as the compositional changes in this and...

  8. Hostel User Study.

    Science.gov (United States)

    Allen, Phyllis

    Findings from a study of living accommodations for young people are given in the first part. Features are identified that are regarded as important by management and residents. Suggestions are made as to how user response may be predicted and the responses of the residents to eight schemes are examined in detail. Also considered are--(1) the…

  9. Shuttle Communications Blackout Study

    Science.gov (United States)

    Haben, R. L.; Budica, R. J.

    1983-01-01

    Space Shuttle Orbiter Entry Communications Blackout Study computer program models, investigates, and predicts communication blackout envelopes based on mission entry trajectory and associated data from tracking stations. Of interest to those designing and using communications systems susceptible to blackout. Program is readily adapted to predict entry communications blackout for any nonablative entry vehicle.

  10. The Study of Language

    Institute of Scientific and Technical Information of China (English)

    吴卞

    2007-01-01

    This paper analyses the study of language based on two aspects: structure and meaning.The paper first gives definition of language.Secondly,the paper summarizes the basic contents of phonology,morphology,syntax,semantics,and pragmatics.Then it focuses on the cooperative principle and the reasons why people violate the maxims and the functions of conversational implicature.

  11. A Study of Memoir.

    Science.gov (United States)

    Arnberg, Amy

    1999-01-01

    Describes a fifth-grade teacher's year-long unit of study on memoir. Addresses getting started, mini-lessons, drafting, and embellishment and voice. Notes that even reluctant writers became involved in writing memoirs and that the teacher followed her own advice and began writing a memoir about her grandmother. Appends a rubric for evaluating…

  12. Studying Aid: Some Methods

    NARCIS (Netherlands)

    D.R. Gasper (Des)

    2003-01-01

    textabstractINVESTIGATING IDEAS, IDEOLOGIES AND PRACTICES This paper presents some methods for trying to make sense of international aid and of its study.1 Some of the methods may be deemed ethnographic; the others are important partners to them, but rather different. In the course of discussing q

  13. Fusion energy studies

    International Nuclear Information System (INIS)

    The following topics are considered: (1) cryosorption vacuum pumping for fusion reactors, (2) TNS support studies, (3) tritium recovery from irradiated Li-Al and SAP, (4) actinide oxides, nitrides, and carbides, and (5) transition metal-actinide-C phase equilibria

  14. NGLW RCRA Storage Study

    International Nuclear Information System (INIS)

    The Idaho Nuclear Technology and Engineering Center (INTEC) at the Idaho National Engineering and Environmental Laboratory contains radioactive liquid waste in underground storage tanks at the INTEC Tank Farm Facility (TFF). INTEC is currently treating the waste by evaporation to reduce the liquid volume for continued storage, and by calcination to reduce and convert the liquid to a dry waste form for long-term storage in calcine bins. Both treatment methods and activities in support of those treatment operations result in Newly Generated Liquid Waste (NGLW) being sent to TFF. The storage tanks in the TFF are underground, contained in concrete vaults with instrumentation, piping, transfer jets, and managed sumps in case of any liquid accumulation in the vault. The configuration of these tanks is such that Resource Conservation and Recovery Act (RCRA) regulations apply. The TFF tanks were assessed several years ago with respect to the RCRA regulations and they were found to be deficient. This study considers the configuration of the current tanks and the RCRA deficiencies identified for each. The study identifies four potential methods and proposes a means of correcting the deficiencies. The cost estimates included in the study account for construction cost; construction methods to minimize work exposure to chemical hazards, radioactive contamination, and ionizing radiation hazards; project logistics; and project schedule. The study also estimates the tank volumes benefit associated with each corrective action to support TFF liquid waste management planning

  15. A Study in Frusteration

    Institute of Scientific and Technical Information of China (English)

    Hou Weili

    2012-01-01

    FOR the past few months. Du Wenhu, a consultant working in a vocational training center in Beijing, has been vexed by a problem that he can't solve. Du wonders whether he should send his daughter back to his hometown in east China's Shandong Province to attend high school there on her own, or let her continue her study in Beijing.

  16. Studying Variation in Tunes

    NARCIS (Netherlands)

    Janssen, B.; van Kranenburg, P.

    2014-01-01

    Variation in music can be caused by different phenomena: conscious, creative manipulation of musical ideas; but also unconscious variation during music recall. It is the latter phenomenon that we wish to study: variation which occurs in oral transmission, in which a melody is taught without the help

  17. Female Studies: No. 1.

    Science.gov (United States)

    Tobias, Sheila

    This document presents an anthology of syllabi of courses taught or proposed during 1969-70 in the field of Womens Studies. The courses originated in a variety of manners. In some colleges, students pressed for courses based on the insights and challenges of women's liberation material. In other institutions, faculty offered interdisciplinary…

  18. HIM Correlational Study

    Science.gov (United States)

    Powell, Evan R.

    1977-01-01

    This study uses two methods of analysis to examine the degree to which items within the cells of the Hill Interaction Matrix correlate. It is found that the table of specifications does not hold up. But the author recommends caution in interpreting this finding. (Author/BP)

  19. Translator Studies in Retrospect

    Institute of Scientific and Technical Information of China (English)

    郭勤

    2009-01-01

    The concern about translator has run for thousands of years on which many translators and translation scholars have made comments.A rough examination of the translator within translation studies at home and abroad is expounded in a loosely chronological way as follows.

  20. Eastern Frequency Response Study

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N.W.; Shao, M.; Pajic, S.; D' Aquila, R.

    2013-05-01

    This study was specifically designed to investigate the frequency response of the Eastern Interconnection that results from large loss-of-generation events of the type targeted by the North American Electric Reliability Corp. Standard BAL-003 Frequency Response and Frequency Bias Setting (NERC 2012a), under possible future system conditions with high levels of wind generation.

  1. Why Indigenous Nations Studies?

    Science.gov (United States)

    Porter, Robert; Yellow Bird, Michael

    2000-01-01

    The development of a new Indigenous Nations Studies program at the University of Kansas is described. Success depended on a critical mass of Indigenous and non-Indigenous faculty and students that had a sense of political and social justice and understood the need for institutional change. The biggest challenge was countering the entrenched…

  2. : Case studies: France

    OpenAIRE

    Bonerandi, Emmanuelle; Santamaria, Frédéric

    2005-01-01

    Case studies on territorial governance : urban region of Lyon (France) and the "Pays" policy (France) in the framework of the ESPON 2.3.2 project Études de cas sur la gouvernance territoriale : région urbaine de Lyon et politique des pays

  3. Studies in portal hypertension

    NARCIS (Netherlands)

    H.R. van Buuren (Henk)

    2002-01-01

    textabstractOur work focussed on one of the most frequent and serious complications of portal hypertension i.e. variceal bleeding. In particular, studies were initiated aimed at developing a more effective therapeutic strategy for the primary and secondary prevention of variceal bleeding. Aspects of

  4. Resources for Women's Studies.

    Science.gov (United States)

    Ridinger, Robert B.

    Over 120 bibliographies and other reference sources relevant to women's studies are identified in this annotated listing. Subjects include feminist scholarship, women in management, popular culture, autobiographies, other cultures and countries, history, lesbian women, women's education, the arts, politics, and rape. In addition to author, title,…

  5. Digital communications study

    Science.gov (United States)

    Boorstyn, R. R.

    1973-01-01

    Research is reported dealing with problems of digital data transmission and computer communications networks. The results of four individual studies are presented which include: (1) signal processing with finite state machines, (2) signal parameter estimation from discrete-time observations, (3) digital filtering for radar signal processing applications, and (4) multiple server queues where all servers are not identical.

  6. ADVANCED CUTTINGS TRANSPORT STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Ergun Kuru; Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Gerald Kane; Len Volk; Mark Pickell; Evren Ozbayoglu; Barkim Demirdal; Paco Vieira; Affonso Lourenco

    1999-10-15

    This report includes a review of the progress made in ACTF Flow Loop development and research during 90 days pre-award period (May 15-July 14, 1999) and the following three months after the project approval date (July15-October 15, 1999) The report presents information on the following specific subjects; (a) Progress in Advanced Cuttings Transport Facility design and development, (b) Progress report on the research project ''Study of Flow of Synthetic Drilling Fluids Under Elevated Pressure and Temperature Conditions'', (c) Progress report on the research project ''Study of Cuttings Transport with Foam Under LPAT Conditions (Joint Project with TUDRP)'', (d) Progress report on the research project ''Study of Cuttings Transport with Aerated Muds Under LPAT Conditions (Joint Project with TUDRP)'', (e) Progress report on the research project ''Study of Foam Flow Behavior Under EPET Conditions'', (f) Progress report on the instrumentation tasks (Tasks 11 and 12) (g) Activities towards technology transfer and developing contacts with oil and service company members.

  7. ADVANCED CUTTINGS TRANSPORT STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Troy Reed; Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Gerald Kane; Mark Pickell; Len Volk; Mike Volk; Barkim Demirdal; Affonso Lourenco; Evren Ozbayoglu; Paco Vieira; Lei Zhou

    2000-01-30

    This is the second quarterly progress report for Year 2 of the ACTS project. It includes a review of progress made in Flow Loop development and research during the period of time between Oct 1, 2000 and December 31, 2000. This report presents a review of progress on the following specific tasks: (a) Design and development of an Advanced Cuttings Transport Facility (Task 2: Addition of a foam generation and breaker system), (b) Research project (Task 6): ''Study of Cuttings Transport with Foam Under LPAT Conditions (Joint Project with TUDRP)'', (c) Research project (Task 7): ''Study of Cuttings Transport with Aerated Muds Under LPAT Conditions (Joint Project with TUDRP)'', (d) Research project (Task 8): ''Study of Flow of Synthetic Drilling Fluids Under Elevated Pressure and Temperature Conditions'', (e) Research project (Task 9): ''Study of Foam Flow Behavior Under EPET Conditions'', (f) Research project (Task 10): ''Study of Cuttings Transport with Aerated Mud Under Elevated Pressure and Temperature Conditions'', (g) Research on instrumentation tasks to measure: Cuttings concentration and distribution in a flowing slurry (Task 11), and Foam properties while transporting cuttings. (Task 12), (h) Development of a Safety program for the ACTS Flow Loop. Progress on a comprehensive safety review of all flow-loop components and operational procedures. (Task 1S). (i) Activities towards technology transfer and developing contacts with Petroleum and service company members, and increasing the number of JIP members. The tasks Completed During This Quarter are Task 7 and Task 8.

  8. ADVANCED CUTTINGS TRANSPORT STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Troy Reed; Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Gerald Kane; Mark Pickell; Len Volk; Mike Volk; Barkim Demirdal; Affonso Lourenco; Evren Ozbayoglu; Paco Vieira

    2000-10-30

    This is the first quarterly progress report for Year 2 of the ACTS project. It includes a review of progress made in Flow Loop development and research during the period of time between July 14, 2000 and September 30, 2000. This report presents information on the following specific tasks: (a) Progress in Advanced Cuttings Transport Facility design and development (Task 2), (b) Progress on research project (Task 8): ''Study of Flow of Synthetic Drilling Fluids Under Elevated Pressure and Temperature Conditions'', (c) Progress on research project (Task 6): ''Study of Cuttings Transport with Foam Under LPAT Conditions (Joint Project with TUDRP)'', (d) Progress on research project (Task 7): ''Study of Cuttings Transport with Aerated Muds Under LPAT Conditions (Joint Project with TUDRP)'', (e) Progress on research project (Task 9): ''Study of Foam Flow Behavior Under EPET Conditions'', (f) Initiate research on project (Task 10): ''Study of Cuttings Transport with Aerated Mud Under Elevated Pressure and Temperature Conditions'', (g) Progress on instrumentation tasks to measure: Cuttings concentration and distribution (Tasks 11), and Foam properties (Task 12), (h) Initiate a comprehensive safety review of all flow-loop components and operational procedures. Since the previous Task 1 has been completed, we will now designate this new task as: (Task 1S). (i) Activities towards technology transfer and developing contacts with Petroleum and service company members, and increasing the number of JIP members.

  9. STUDY OF ENTEROCUTANEOUS FISTULA

    Directory of Open Access Journals (Sweden)

    Arti

    2015-03-01

    Full Text Available BACKGROUND: A fistula is defined as abnormal communication between two epithelial surfaces . 1 Enterocutaneous fistula is defined as abnormal communication between hollow organ and skin. They are classified as congenital or acquired. We have excluded congenital and internal fistulas. We have also excluded esophageal, urinary, p ancreatic and biliary fistulas as their management is complex and differs significantly from enterocutaneous fistulas. AIM: 1. Study of aetiology, pathophysiology and management of enterocutaneous fistula. To evaluate previously laid principles of management of enterocutaneous fistula. 2. To assess the feasibility of early intervention safety and outcome as the conservative long term treatment appears to be cost prohibitive. 3. To study morbidity and mortality related to enterocutaneous fistula. MATERIAL AND METHODS: In all, 50 cases of enterocutaneous fistula were studied during a period from June 2012 to N ovember 2014 at a Government tertiary care C entre. Both, patients referred from other centres with post - operative fistulas and fistulas developed in this institute after surgeries or spontaneously were included in the study after fulfilling the inclusion and exclusion criteria. RESULT S : The maximum numbers of cases were between 39 - 48 years of age group. Spontaneous closure was achieved in 72.7% and surgical closure in 76.7% of the patients Vacuum assisted closure was achieved in 66.66% of the patients in whom VAC was used. Of the patients in whom octreotide was used closure was achieved in 66.66% of the patients. The association between serum albumin levels and fistula healing and between fistula output and mortality were statistically significant. Overall mortality in this study was 26% with 44.44% among referred cases and 15.625% among institutional cases.

  10. Studying bacterial multispecies biofilms

    DEFF Research Database (Denmark)

    Røder, Henriette Lyng; Sørensen, Søren Johannes; Burmølle, Mette

    2016-01-01

    The high prevalence and significance of multispecies biofilms have now been demonstrated in various bacterial habitats with medical, industrial, and ecological relevance. It is highly evident that several species of bacteria coexist and interact in biofilms, which highlights the need for evaluating...... the approaches used to study these complex communities. This review focuses on the establishment of multispecies biofilms in vitro, interspecies interactions in microhabitats, and how to select communities for evaluation. Studies have used different experimental approaches; here we evaluate the benefits...... and drawbacks of varying the degree of complexity. This review aims to facilitate multispecies biofilm research in order to expand the current limited knowledge on interspecies interactions. Recent technological advances have enabled total diversity analysis of highly complex and diverse microbial communities...

  11. E85 Dispenser Study

    Energy Technology Data Exchange (ETDEWEB)

    Moriarty, K.; Johnson, C.; Sears, T.; Bergeron, P.

    2009-12-01

    This study reviews E85 dispensing infrastructure advances and issues and evaluates the geographic concentration of flexible fuel vehicles (FFVs), E85 stations, ethanol production facilities, and E85 suppliers. Costs, space, financial incentives, and barriers to adding E85 fueling equipment at existing stations are also assessed. This study found that E85 is increasingly available in the U.S. in half of the states; however, the other half have minimal or no E85 fueling options. Despite these gains, E85 is only available at 1% of U.S. gasoline stations. Ethanol production reached 9.5 billion gallons in 2008, but less than 1% is consumed as E85. FFVs have not reached a significant concentration in any county, metropolitan area, or state.

  12. Southeast continental shelf studies

    Energy Technology Data Exchange (ETDEWEB)

    Menzel, D.W.

    1979-02-12

    Research efforts on the southeast continental shelf currently describe the manner in which fluctuations in Gulf Stream motion influence biological and chemical processes. Current meter arrays are maintained in the Georgia Bight and in Onslow Bay to describe general circulation patterns and to identify forcing functions. biological studies describe processes affecting temporal and spatial variations on the shelf and have attempted to track the biological history of intruded Gulf Stream water masses. Chemical studies examine the influence of both physical and biological variables on the distribution and fate of trace elements. The current state of knowledge is reviewed, the hypotheses developed and are described, a rationale for testing these hypotheses is given. 1 figure, 1 table.

  13. Heliostat cost optimization study

    Science.gov (United States)

    von Reeken, Finn; Weinrebe, Gerhard; Keck, Thomas; Balz, Markus

    2016-05-01

    This paper presents a methodology for a heliostat cost optimization study. First different variants of small, medium sized and large heliostats are designed. Then the respective costs, tracking and optical quality are determined. For the calculation of optical quality a structural model of the heliostat is programmed and analyzed using finite element software. The costs are determined based on inquiries and from experience with similar structures. Eventually the levelised electricity costs for a reference power tower plant are calculated. Before each annual simulation run the heliostat field is optimized. Calculated LCOEs are then used to identify the most suitable option(s). Finally, the conclusions and findings of this extensive cost study are used to define the concept of a new cost-efficient heliostat called `Stellio'.

  14. The New Modernist Studies

    Directory of Open Access Journals (Sweden)

    Douglas Mao

    2014-01-01

    Full Text Available The main task of this article is to describe the new situation of modernist studies at the turn of the 20th century and an attempt to position this description in a broader history of criticism of modernism in art. The transformations in the studies into modernist literature have been characterized here in three aspects: expanding the time frame (going beyond the basic period of modernism from the end of the 19th c. until 1930s, spatial dimension (abandonment of a privileged position of research into West European and American modernism in favour of a transnational perspective and vertical dimension (connected with the necessity to rethink the relationship high art-low art, and also the influence of mass media upon modernist literature.

  15. Objectivist case study research

    DEFF Research Database (Denmark)

    Ridder, Hanne Mette Ochsner; Fachner, Jörg

    2016-01-01

    be achieved through the use of objectivist case study research. The strength of the case study design is that it allows for uncovering or suggesting causal relationships in real-life settings through an intensive and rich collection of data. According to Hilliard (1993), the opposite applies for extensive......In order to comprehend the impact of music therapy or music therapy processes, a researcher might look for an approach where the topic under investigation can be understood within a broader context. This calls for a rich inclusion of data and consequently a limited number of participants and may...... designs, in which a small amount of data is gathered on a large number of subjects. With the richness of data, the intensive design is ―the primary pragmatic reason for engaging in single-case or small N research‖ (p. 374) and for working from an idiographic rather than a nomothetic perspective....

  16. NASA study grants

    Science.gov (United States)

    To expand human exploration of the Solar System, the Office of Exploration of the National Aeronautics and Space Administration has awarded 20 contracts for ideas, concepts, devices, systems, and trajectory, operation and implementation plans. Winning proposals came from five industry-related firms, two organizations in the space-support business, and thirteen universities; they were chosen from 115 entries.Geophysical studies to be supported include site characterization of the Oregon moonbase (Oregon L-5 Society, Inc., Oregon City), evolution of design alternatives for exploration of Mars by balloon (Titan Systems, Inc., San Diego, Calif.), design considerations of a lunar production plant (Boston University, Chestnut Hill, Mass.), planetary materials and resource utilization (Michigan Technological University, Houghton), Mars tethered sample return study (University of Colorado, Boulder), Teleprospector, a teleoperated robotic field geologist (University of New Mexico, Albuquerque), and the International Lunar Polar Orbiter (International Space University, Boston, Mass.).

  17. Options Study - Phase II

    Energy Technology Data Exchange (ETDEWEB)

    R. Wigeland; T. Taiwo; M. Todosow; W. Halsey; J. Gehin

    2010-09-01

    The Options Study has been conducted for the purpose of evaluating the potential of alternative integrated nuclear fuel cycle options to favorably address the issues associated with a continuing or expanding use of nuclear power in the United States. The study produced information that can be used to inform decisions identifying potential directions for research and development on such fuel cycle options. An integrated nuclear fuel cycle option is defined in this study as including all aspects of the entire nuclear fuel cycle, from obtaining natural resources for fuel to the ultimate disposal of used nuclear fuel (UNF) or radioactive wastes. Issues such as nuclear waste management, especially the increasing inventory of used nuclear fuel, the current uncertainty about used fuel disposal, and the risk of nuclear weapons proliferation have contributed to the reluctance to expand the use of nuclear power, even though it is recognized that nuclear power is a safe and reliable method of producing electricity. In this Options Study, current, evolutionary, and revolutionary nuclear energy options were all considered, including the use of uranium and thorium, and both once-through and recycle approaches. Available information has been collected and reviewed in order to evaluate the ability of an option to clearly address the challenges associated with the current implementation and potential expansion of commercial nuclear power in the United States. This Options Study is a comprehensive consideration and review of fuel cycle and technology options, including those for disposal, and is not constrained by any limitations that may be imposed by economics, technical maturity, past policy, or speculated future conditions. This Phase II report is intended to be used in conjunction with the Phase I report, and much information in that report is not repeated here, although some information has been updated to reflect recent developments. The focus in this Options Study was to

  18. Critical Digital Tourism Studies

    DEFF Research Database (Denmark)

    Gyimóthy, Szilvia; Munar, Ana María

    2013-01-01

    This paper advocates the need for a critical and cross-disciplinary research agenda on the field of digital technologies and tourism. The changing virtual landscape of tourism has received increased attention by tourism scholars. However, contemporary studies on information technologies (IT...... dimensions, ethics, and cultural values shaping digital tourism). This proposal contributes to increasing research reflexivity in understanding how tourism is enacted through digital worlds and how digital technologies evolve through tourism practices. Critical-thinking and socio-political engagement......) are approached mostly from a business administration perspective and informed by conceptual frameworks developed in management and marketing. IT studies in tourism are still at a stage similar to the first advocacy phase of tourism research in general (Jafari, 1990) and are seldom inspired by relevant...

  19. World Biofuels Study

    Energy Technology Data Exchange (ETDEWEB)

    Alfstad,T.

    2008-10-01

    This report forms part of a project entitled 'World Biofuels Study'. The objective is to study world biofuel markets and to examine the possible contribution that biofuel imports could make to help meet the Renewable Fuel Standard (RFS) of the Energy Independence and Security Act of 2007 (EISA). The study was sponsored by the Biomass Program of the Assistant Secretary for Energy Efficiency and Renewable Energy (EERE), U.S. Department of Energy. It is a collaborative effort among the Office of Policy and International Affairs (PI), Department of Energy and Oak Ridge National Laboratory (ORNL), National Renewable Energy Laboratory (NREL) and Brookhaven National Laboratory (BNL). The project consisted of three main components: (1) Assessment of the resource potential for biofuel feedstocks such as sugarcane, grains, soybean, palm oil and lignocellulosic crops and development of supply curves (ORNL). (2) Assessment of the cost and performance of biofuel production technologies (NREL). (3) Scenario-based analysis of world biofuel markets using the ETP global energy model with data developed in the first parts of the study (BNL). This report covers the modeling and analysis part of the project conducted by BNL in cooperation with PI. The Energy Technology Perspectives (ETP) energy system model was used as the analytical tool for this study. ETP is a 15 region global model designed using the MARKAL framework. MARKAL-based models are partial equilibrium models that incorporate a description of the physical energy system and provide a bottom-up approach to study the entire energy system. ETP was updated for this study with biomass resource data and biofuel production technology cost and performance data developed by ORNL and NREL under Tasks 1 and 2 of this project. Many countries around the world are embarking on ambitious biofuel policies through renewable fuel standards and economic incentives. As a result, the global biofuel demand is expected to grow very

  20. Botswana country study

    Energy Technology Data Exchange (ETDEWEB)

    1999-09-01

    This study was carried out in Botswana, Tanzania and Zambia as part of the project `Climate Change Mitigation in Southern Africa` funded by the Danish International Development Agency (Danida). The project was conducted parallel to the UNEP/GEF project `Economics of Greenhouse Gas Limitations` which involved 8 other developing countries and 2 regional projects in Latin America and the SADC region. The limitation of greenhouse gas (GHG) emissions is a complex issue, intimately connected with economic development at local, national, regional and global levels. Key economic sectors such as energy, agriculture, industry and forestry all produce GHGs, and are likely to be affected directly and indirectly by any mitigation policy. The UNEP Greenhouse Gas Abatement Costing Studies, initiated in 1991, attempted to address these complex issues, developing a methodological framework and testing it through practical application in ten countries. (EHS) 28 refs.

  1. Studies on provoked asthma

    International Nuclear Information System (INIS)

    A group of adult patients with perennial bronchial asthma has been studied as to lung perfusion and alveolar ventilation (81m-Kr) at rest and after provocation of an acute attack. Asthma was provoked by exercise and by histamine inhalation. After provocation the peak expiratory flow values were reduced to less than 80% of the base line values. Perfusion was often deranged. Regional ventilation changed rapidly after provocation and not always in the same fashion after exercise and histamine. During attacks lung volume increased. The expansion decreased (in parallel with increased peak expiratory flow) after inhalator of a #betta#-2 agonist (terbutaline). 81m-Kr offers unique opportunities for studying acute regional changes in alveolar ventilation. (Author)

  2. Fra studie til arbejdsliv

    DEFF Research Database (Denmark)

    Andersen, Line Palle

    2015-01-01

    Universitet (2009) som den første beskæftiget sig med udfordringerne ved overgangen fra studie til arbejdsliv. Undertegnede har i samarbejde med PhD-studerende Helle Bach Riis udført 25 kvalitative interviews blandt danske akademikere, der har været på arbejdsmarkedet ml ½-5 år. Vores undersøgelser bekræfter...... indenfor sit eget felt. Efter 3-4 år på arbejdsmarkedet er ens viden fra uddannelsen bearbejdet og integreret og en naturlig basis ved løsning af arbejdsopgaver. Både uddannelser, aftagerfeltet og kandidaten kan gøre en aktiv indsats, der gør overgangen fra studie til arbejdsliv nemmere. For uddannelsernes...

  3. Studying bilingual students’ literacy

    DEFF Research Database (Denmark)

    Laursen, Helle Pia

    2012-01-01

    contribute to lift the basic understanding of bilinguals’ literacy out of a disqualifying political discourse. Drawing on the ongoing study Sign of Language (Laursen, 2011), I reflect on how a social semiotic framework might help open new research perspectives on bilingual children’s literacy acquisition......In the official educational discourse in the Nordic countries literacy teaching has become a central and contested issue. In both public and political debate literacy seems to be constructed as a unified concept streamlined for administration and measurement (Prinsloo & Baynham, 2008...... by recognizing as well the child's agency and the micro-stories embedded in the creation of signs as the discursive macro-stories surrounding the meaning making processes. The longitudinal study Signs of Language (2008-2014) involves five multilingual classrooms and aims at getting insight into the children...

  4. Study on market policy

    International Nuclear Information System (INIS)

    In April 2007 the Dutch Minister of Economic Affairs promised the Lower House a study of the development of the public interests of quality, accessibility and efficiency after the introduction of market liberalization. In the debate on market liberalization in May 2007 the Minister complied with the Lower House?s request to include the consequences of the market liberalization operations on sectoral employment and labor conditions. This study addresses two questions: (1) Which developments occurred in the field of public interests quality, accessibility and efficiency and labor conditions since the introduction of market liberalization? and (2) What general findings and conclusions can be drawn from the implemented market liberalization policy in various sectors? What lessons can be learned for the future? Several sectors have been examined, including large energy users; renewable energy; energy market for medium users; energy (gas and electricity)

  5. Construction Management : Study Book

    OpenAIRE

    Ilveskoski, Olli; Niittymäki, Seppo

    2015-01-01

    This publication is a summary of the Construction Management course handscript. The objective is that as the students gets involved with the Construction Management of Building Projects they will learn Construction Management topics like Building Process, Production planning, Quantity Take Off, Cost Estimation, Scheduling, Work Safety and Quality Control. The study book has been in use in Construction Management courses in Häme University of Applied Sciences.

  6. Electron microscope studies

    International Nuclear Information System (INIS)

    This year our laboratory has continued to make progress in the design of electron-optical systems, in the study of structure-function relationships of large multi-subunit proteins, in the development of new image processing software and in achieving a workable sub-angstrom STEM. We present an algebraic approach to the symmetrical Einzel (unipotential) lens wherein we simplify the analysis by specifying a field shape that meets some preferred set of boundary or other conditions and then calculate the fields. In a second study we generalize this approach to study of three element electrostatic lenses of which the symmetrical Einzel lens is a particular form. The purpose is to develop a method for assisting in the design of a lens for a particular purpose. In our biological work we study a stable and functional dodecameric complex of globin chains from the hemoglobin of Lumbricus terrestris. This is a complex lacking the ''linker'' subunit first imaged in this lab and required for maintenance of the native structure. In addition, we do a complete work-up on the hemoglobin of the marine polychaete Eudistylia vancouverii demonstrating the presence of a hierarchy of globin complexes. We demonstrate stable field-emission in the sub-angstrom STEM and the preliminary alignment of the beam. We continue our exploration of a algorithms for alignment of sequences of protein and DNA. Our computer facilities now include four second generation RISC workstations and we continue to take increasing advantage of the floating-point and graphical performance of these devices

  7. Journal of Development Studies

    OpenAIRE

    Hou, X.H.

    2010-01-01

    This study uses cross-sectional time-series data to examine the relationship between wealth and child labour and schooling in Pakistan and finds that wealth is crucial in determining a child's activities, but is far from being a sufficient condition to enrol a child in school. This is particularly the case for rural girls. Nonparametric analysis shows a universal increase in school enrolment for rural girls from 1998-2006 and this increase is independent of wealth. Multinomial logit regressio...

  8. American Studies in Russia

    Directory of Open Access Journals (Sweden)

    Olga Antsyferova

    2006-01-01

    Full Text Available Interest in the USA, both general and specifically academic, has always existed in Russia, with its own ups and downs. But American studies as an academic discipline started gaining its popularity probably after WWII when there sporadically started to emerge the ever-increasing number of academic books, articles and dissertations in literary and historical research on the USA, the main centers of which were founded at the Academic Research Institute of the USA and Canada, headed by academicia...

  9. Internet Studies in Europe

    OpenAIRE

    O'Neil, Mathieu

    2013-01-01

    Internet studies have historically developed in the United States. The Oxford Internet Institute (OII), launched in 2001, was the first European Internet research department - rather than a research centre or programme in a disciplinary department, the OII was able to offer degrees. To some extent, OII has managed to create an analytical perspective distinct from the cyber-law focus of major US research centres such as Harvard's Berkman Centre for Internet and Society and the Annenberg School...

  10. Laser Initiated Actuator study

    Energy Technology Data Exchange (ETDEWEB)

    Watson, B.

    1991-06-27

    The program task was to design and study a laser initiated actuator. The design of the actuator is described, it being comprised of the fiber and body subassemblies. The energy source for all experiments was a Spectra Diode 2200-H2 laser diode. The diode is directly coupled to a 100 micron core, 0.3 numerical aperture fiber optic terminated with an SMA connector. The successful testing results are described and recommendations are made.

  11. American Studies in Hungary

    Directory of Open Access Journals (Sweden)

    Éva Federmayer

    2006-01-01

    Full Text Available The beginning of American Studies as an academic discipline at Hungarian colleges and universities is basically coterminous with the watershed years of 1989-1990 when the country made a radical shift from state socialism toward parliamentary democracy and a free economy. This political and economic about-face, which came hand in hand with the undermining of foundationalist certainties and the generation of new anxieties coincided, more or less, with the radical transformation that American St...

  12. Cytochemical studies in leukaemias

    Directory of Open Access Journals (Sweden)

    Batra Neelam

    1978-01-01

    Full Text Available One hundred cases of acute leukaemia were studied, by Romanowsky stains and by cytochemical stains such as Sudan Black B, Periodic Acid Schiff, Alkaline phosphatase and Peroxidase stains. Cases difficult to diagnose by Romanowsky stained smears were easily classified by these supplementary stains. Their importance as supplements to the routine Romanowsky staining in the diagnosis of leukaemia is emphasized and the division of acute lymphoblastic leukaemia based on these patterns is suggested.

  13. Decommissioning and decontamination studies

    International Nuclear Information System (INIS)

    The decommissioning of retired Hanford facilities requires careful consideration of environmentally-related factors. Applicable ecology programs have been designed to: develop the technology associated with burial ground stabilization, thereby minimizing biotic access and transport of radioactive wastes and, characterize present 300 Area burial grounds to ascertain the potential biotic transport of waste materials away from managed facilities. Results are reported from studies on the role of plants, small mammals, and ants as potential transport vectors of radionuclides from radioactive waste burial grounds

  14. Study of aeroball injuries.

    OpenAIRE

    Sinha, A; McGlone, R G; Montgomery, K.

    1997-01-01

    OBJECTIVE: To present the risks of aeroball, a new sport played by either two or four players on a trampoline court surrounded by specially constructed fabric walls, and to propose ways to increase awareness and reduce the incidence of injury, in particular, ankle injury. METHOD: A study was carried out to document the nature of aeroball related incidents, between 1991 and 1995, at Lancaster University Sports Centre. Lace-up ankle supports were introduced in April 1992, and their effect on th...

  15. Paraffin Oxidation Studies

    OpenAIRE

    Mrs. S. J. Purohit; Dr. Milind Pradhan

    2013-01-01

    The oxidation of paraffin has been studied with keen interest by several workers from all over the world; as oxidation leads to the introduction of various functional groups in hydrocarbon chains. Processes involving the Oxidation of Paraffin’s in the liquid phase, using air or oxygen are of great importance to industrialized economies because of their role in converting petroleum hydrocarbon feed stocks such as alkanes, olefins and aromatics into industrial organic chemicals important in the...

  16. Master Study: Ceramics

    Science.gov (United States)

    Clark, Kelly

    2004-01-01

    In painting and drawing classes, it is typical to ask students to work directly from a master. It is one way to study composition techniques, and to become familiar with classical style firsthand. In museums, easels are set up as artists work, not in an attempt to copy or plagiarize, but in an attempt to be part of history by participating in it.…

  17. Electroweak studies at TRISTAN

    International Nuclear Information System (INIS)

    The TRISTAN experiments have each accumulated about 60 pb-1 of data. Systematic analyses have been carried out on most of the available processes, including leptonic pair and multihadronic production as well as higher order processes. Here recent results on electroweak studies are reviewed by emphasizing those which seem to be in disagreement with the standard model. Although all the results are consistent with the theory, some show slight deviations from the theoretical expectations. (author)

  18. a prospective comparative study

    OpenAIRE

    Jäckel, Tanja

    2011-01-01

    Objective: To examine effectiveness and safety of homoeopathic vs. conventional treatment for children with atopic eczema in usual care. In a prospective multicentre comparative observational non-randomized study 135 patients (1-14 years old, homoeopathy n=48 vs. conventional n=87) with moderate atopic eczema were included. Treatment was left to the physicians´preferences in both groups. The primary endpoint was the SCORAD (SCOring Atopic Dermatitis) after 6 months. Secondary outcom...

  19. The Videofluorographic Swallowing Study

    OpenAIRE

    Martin-Harris, Bonnie; Jones, Bronwyn

    2008-01-01

    The evidence for the physiologic foundation and interpretation of the videofluorographic swallowing study (VFSS) is described. The purpose and clinical utility of VFSS are explained. Standardization of the VFSS procedure, protocol, interpretation and reporting is highlighted as a critical step in future clinical practice and in clinical research. Individualized, evidenced –based rehabilitation strategies are presented as key components that are systematically applied during the VFSS procedure...

  20. a numerical study

    OpenAIRE

    Sousa, Antonio C. M.

    2015-01-01

    This paper reports on a numerical study for steady flow and heat transfer distribution for a configuration relevant to Liquid Composite Molding, where agap between a porous substrate and the solid boundary of a mold cavity yieldsan edge flow. The flowwithin the porous domain is modeled by the Brinkman-Forchheimer formulation, and the edge flow itself is described by theNavier-Stokes equations. The cure of the fluid (resin) is simulated as a volumetric heat generation. The predictions are obta...

  1. Studying Aid: Some Methods

    OpenAIRE

    Gasper, Des

    2003-01-01

    textabstractINVESTIGATING IDEAS, IDEOLOGIES AND PRACTICES This paper presents some methods for trying to make sense of international aid and of its study.1 Some of the methods may be deemed ethnographic; the others are important partners to them, but rather different. In the course of discussing questions of aid policy and practice—such as: Should international development aid exist at all? How should aid be conducted? Should humanitarian relief be provided in conflict situations when it can ...

  2. Dynamic function studies

    International Nuclear Information System (INIS)

    Dynamic function studies can be defined as a measure of the variation of a quantity of a substance in an organ with time. Such studies are clinically useful only when the underlying physiological model is realistic. Usually the measurements are of three kinds: the uptake function, the transit function and the removal function. Sensitivity of these measurements can be enhanced in several clinical situations by intervention, such as exercise or drugs. It is possible to display a nuclear image in a variety of ways through computer manipulations which are justified only if based on a valid physiological model. The newer radiopharmaceuticals have also increased the range of functions that can be studied, especially in the case of the heart and the brain. Positron emission tomography (PET) images are fascinating but they are prohibitively expensive and routine clinical nuclear medicine will have to rely on information obtained with single photon emission computer tomography (SPECT). In the diagnosis of cancer, the instrument alone would not improve the diagnosis. It is necessary to have radiopharmaceuticals with a high degree of specificity of uptake. This can possibly be achieved with immunoscintigraphy. There also, the kinetics of uptake of the labelled antibody enable one to differentiate specific from non-specific uptake. The need for good reliable dynamic function studies is as great in the developing as in the developed countries, but a nuclear medicine specialist in a developing country would need more skills and experience because of the heavy odds against which one would be working. (author). 43 refs, 2 figs

  3. Speech Alarms Pilot Study

    Science.gov (United States)

    Sandor, Aniko; Moses, Haifa

    2016-01-01

    Speech alarms have been used extensively in aviation and included in International Building Codes (IBC) and National Fire Protection Association's (NFPA) Life Safety Code. However, they have not been implemented on space vehicles. Previous studies conducted at NASA JSC showed that speech alarms lead to faster identification and higher accuracy. This research evaluated updated speech and tone alerts in a laboratory environment and in the Human Exploration Research Analog (HERA) in a realistic setup.

  4. Family studies in glaucoma.

    OpenAIRE

    Rosenthal, A R; Perkins, E S

    1985-01-01

    Two groups of patients with a family history of chronic open-angle glaucoma were compared with a normal population of 5919 individuals studied during the Bedford Glaucoma Survey. The mean screening intraocular pressure was significantly raised in both groups with a family history of chronic open-angle glaucoma. The prevalence rate of a raised intraocular pressure was 3.81 times that found in the normal population. This relationship was maintained when age-dependent prevalence rates were evalu...

  5. Radiopharmaceuticals for cerebral studies

    International Nuclear Information System (INIS)

    For obtain good brain scintillation images in nuclear medicine must be used several radiopharmaceuticals. Cerebral studies give a tumors visual image as well as brain anomalities detection and are helpful in the diagnostic diseases . Are described in this work: a cerebrum radiopharmaceuticals classification,labelled compounds proceeding and Tc 99m good properties in for your fast caption, post administration and blood purification for renal way

  6. WEB PLAGIARISM: EMPIRICAL STUDY

    OpenAIRE

    Alexander E. Voiskounsky

    2009-01-01

    A questionnaire measuring web plagiarism (or academic cheating), worked out by Underwood and Szabo (2003) has been adapted and applied to the population of undergraduate science students in Russia. The students at four technical universities are questioned (N=292). The study shows the students perform webplagiarizing, i.e. take materials from the Internet and hand these materials in as their own assignments. Russian students are reportedly competent in the use of the Internet; they report to ...

  7. Indonesia country study

    Energy Technology Data Exchange (ETDEWEB)

    1999-09-01

    This study demonstrated the use of MARKAL model in carbon mitigation analysis for both energy and forestry sector. Four scenarios were used namely: 1. EbFb (baseline scenario). In this scenario, mitigation technologies in the energy sector were not included in the model and no target was set up for increasing net carbon uptake by forest activities. 2. EmFb. Mitigation technologies in the energy sector were included with the target of reducing cumulative net carbon emission by about 13% and activities in the forestry sectors were the same as those in baseline. 3. EbFm. Mitigation technologies in the energy sector were not included and the forestry activities were targeted to increase the carbon uptake so that the cumulative net carbon emission decreased by 13%. 4. EmFm. Mitigation technologies in the energy sector were included as well as forestry sector with target of reducing cumulative net carbon emission by about 35%. This study indicates that the MARKAL model has the potential to be used for mitigation analysis for both energy and forestry sectors. However, there are some limitations encountered during the study. The program is not able to accommodate the delayed emission from the forestry sector in a manner consistent to the treatment of emissions in the energy sector. In addition, there are some technical problems that still need to be resolved such as the inclusion of soil carbon uptake calculation in the model and the verification of carbon uptake calculation. In this study, all carbon uptakes was assumed to occur at the time of planting. (EHS) 37 refs.

  8. Corporate Governance. Case Studies

    OpenAIRE

    Manuel, Eduardo

    2007-01-01

    This paper pretends to do a theoretical approach of Corporate Governance, having as support some case studies about companies like Coca-Cola, Nokia, Microsoft, and Amazon.com. The methodology adopted for this work is based in information from these companies available in their websites and annual reports. I concluded that both companies show the corporate governance components according to their core business and their environmental business.

  9. Case study - Czechoslovakia

    International Nuclear Information System (INIS)

    In the lecture Case Study - Czechoslovakia with the sub-title 'Unified System of Personnel Preparation for Nuclear Programme in Czechoslovakia' the actual status and the current experience of NPP personnel training and preparation in Czechoslovakia are introduced. The above mentioned training system is presented and demonstrated by the story of a proxy person who is going to become shift engineer in a nuclear power plant in Czechoslovakia. (orig./HP)

  10. Food Fortification Stability Study

    Science.gov (United States)

    Sirmons, T. A.; Cooper, M. R.; Douglas, G. L.

    2016-01-01

    This study aims to assess the stability of vitamin content, sensory acceptability and color variation in fortified spaceflight foods over a period of 2 years. Findings will identify optimal formulation, processing, and storage conditions to maintain stability and acceptability of commercially available fortification nutrients. Changes in food quality are being monitored to indicate whether fortification affects quality over time (compared to the unfortified control), thus indicating their potential for use on long-duration missions.

  11. Heavy flavors study group

    International Nuclear Information System (INIS)

    The heavy flavor study group concentrated on three issues. First the investigation of an energy transverse trigger to be used to select out charm and beauty events. Second, in a dedicated high sensitivity two-body B experiment is it possible to ''tag'' the beauty particle. Third, the design of a photoproduction experiment that could accumulate 108 charm particles in a single Fermilab running period

  12. Electron microscope studies

    Energy Technology Data Exchange (ETDEWEB)

    Crewe, A.V.; Kapp, O.H.

    1991-06-01

    This year our laboratory has continued to make progress in the design of electron-optical systems, in the study of structure-function relationships of large multi-subunit proteins, in the development of new image processing software and in achieving a workable sub-angstrom STEM. We present an algebraic approach to the symmetrical Einzel (unipotential) lens wherein we simplify the analysis by specifying a field shape that meets some preferred set of boundary or other conditions and then calculate the fields. In a second study we generalize this approach to study of three element electrostatic lenses of which the symmetrical Einzel lens is a particular form. The purpose is to develop a method for assisting in the design of a lens for a particular purpose. In our biological work we study a stable and functional dodecameric complex of globin chains from the hemoglobin of Lumbricus terrestris. This is a complex lacking the linker'' subunit first imaged in this lab and required for maintenance of the native structure. In addition, we do a complete work-up on the hemoglobin of the marine polychaete Eudistylia vancouverii demonstrating the presence of a hierarchy of globin complexes. We demonstrate stable field-emission in the sub-angstrom STEM and the preliminary alignment of the beam. We continue our exploration of a algorithms for alignment of sequences of protein and DNA. Our computer facilities now include four second generation RISC workstations and we continue to take increasing advantage of the floating-point and graphical performance of these devices.

  13. The Study of Education.

    OpenAIRE

    Hogan, Padraig; Carr, Wilfred; Griffiths, Morwenna

    2007-01-01

    In 1996, a collection of essays edited by J.W. Tibble and titled The Study of Education was published in the UK. This contained contributions on philosophy of education (R.S. Peters), educational theory (P.H. Hirst), history of education (B. Simon), psychology of education (B. Morris), sociology of education (W. Taylor). In 1983, three of the same authors (Hirst, Peters, Simon), together with J. Nisbet (educational psychology) and B. Davies (sociology of education, contributed to a further co...

  14. Electroencephalographic studies of sleep

    Science.gov (United States)

    Webb, W. B.; Agnew, H. W., Jr.

    1975-01-01

    Various experimental studies on sleep are described. The following areas are discussed: (1) effect of altered day length on sleep, (2) effect of a partial loss of sleep on subsequent nocturnal sleep; (3) effect of rigid control over sleep-wake-up times; (4) sleep and wakefulness in a time-free environment; (5) distribution of spindles during a full night of sleep; and (6) effect on sleep and performance of swiftly changing shifts of work.

  15. Studies of Embodied Interaction

    OpenAIRE

    Stycke, Simon; Castillo Hansen, Frederikke; Debel, Niels; Heebøll, Lauge; Mohr, Markus

    2013-01-01

    The purpose of this project was to perform general studies on the phenomenon Embodied Interaction. Our motivation for doing this was the increasing interest, both creatively and commercially, in new ways to use our computer technologies in the tangible world, as well as in affecting the human perception. Embodied Interaction allows a person to use his body as an instrument in the world, and utilize his bodily presence and motions, to control software and hardware alike. By delv...

  16. Case Studies - Cervical Cancer

    Centers for Disease Control (CDC) Podcasts

    2010-10-15

    Dr. Alan Waxman, a professor of obstetrics and gynecology at the University of New Mexico and chair of the American College of Obstetricians and Gynecologists (ACOG) committee for the underserved, talks about several case studies for cervical cancer screening and management.  Created: 10/15/2010 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP), Division of Cancer Prevention and Control (DCPC).   Date Released: 6/9/2010.

  17. Purified water quality study

    Energy Technology Data Exchange (ETDEWEB)

    Spinka, H.; Jackowski, P.

    2000-04-03

    Argonne National Laboratory (HEP) is examining the use of purified water for the detection medium in cosmic ray sensors. These sensors are to be deployed in a remote location in Argentina. The purpose of this study is to provide information and preliminary analysis of available water treatment options and associated costs. This information, along with the technical requirements of the sensors, will allow the project team to determine the required water quality to meet the overall project goals.

  18. Tanzania country study

    Energy Technology Data Exchange (ETDEWEB)

    1999-09-01

    Objectives of this study are to analyse the role of the land use sectors of Tanzania (especially forestry) on mitigation of greenhouse gases. Specific emphasis is placed on the relationship between forestry and energy supply from biomass, as well as other forestry products. This is a follow up study on an earlier effort which worked on mitigation options in the country without and in-depth analysis of the forestry and land use sectors. Analysis of the mitigation scenario has been based on Comprehensive Mitigation Analysis (COMAP). This study has analysed the forestry and land use sector behaviour on the basis of the current policies on land and environment. Furthermore three scenarios have been developed on the basis of what is expected to happen in the sectors, the worse scenario being a catastrophic one where if things takes the business as usual trend then the forest resources will easily be depleted. The TFAP scenario takes into account the implementation of the current plans as scheduled while the mitigation scenario takes into account the GHG mitigation in the implementation of the plans. A Comprehensive Mitigation Analysis Process (COMAP) has been used to analyse the GHG and cost implications of the various programmes under the mitigation scenario. (au) 30 refs.

  19. 1970 British Cohort Study

    Directory of Open Access Journals (Sweden)

    Matt Brown

    2014-10-01

    Full Text Available The 1970 British Cohort Study (BCS70 is one of Britain’s world famous national longitudinal birth cohort studies, three of which are run by the Centre for Longitudinal Studies at the Institute of Education, University of London.  BCS70 follows the lives of more than 17,000 people born in England, Scotland and Wales in a single week of 1970. Over the course of cohort members lives, the BCS70 has collected information on health, physical, educational and social development, and economic circumstances among other factors. Since the birth survey in 1970, there have been nine ‘sweeps’ of all cohort members at ages 5, 10, 16, 26, 30, 34, 38 and most recently at 42. Data has been collected from a number of different sources (the midwife present at birth, parents of the cohort members, head and class teachers, school health service personnel and the cohort members themselves. The data has been collected in a variety of ways including via paper and electronic questionnaires, clinical records, medical examinations, physical measurements, tests of ability, educational assessments and diaries. The majority of BCS70 survey data can be accessed by bona fide researchers through the UK Data Service at the University of Essex.

  20. Review - Critical Han Studies

    Directory of Open Access Journals (Sweden)

    Zhiguo Ye

    2013-12-01

    Full Text Available Review of: Thomas Mullaney, James Leibold, Stéphane Gros, and Eric Armand Vanden Bussche (eds. 2012. Critical Han Studies: The History, Representation, and Identity of China's Majority. Berkeley, Calif: University of California Press. This path-breaking volume is an academic collaboration that emerged out of the "Critical Han Studies Conference and Workshop" at Stanford University in April 2008. Eleven scholars contributed to the question of what it means to be 'Han' in China, both historically and at present. Constituting over ninety percent of China's population, the Han are not only the largest ethnic group in China, but are also one of the largest categories of collective identity in the world. Despite this, the dominant Han group has so far eluded careful scholarly scrutiny, with the Han often referred to as an unmarked majority category in contemporary China. This volume challenges such conventional views by conceptualizing new interdisciplinary approaches to the question of Hanness. The eleven essays of the volume are divided into three themes: 'Han and China', 'The Problem of Han Origins', and 'The Problem of Han Formations'. The first theme, comprised of four essays, analyzes the ties that bind the category of Han to those of Chinese ethnicity, race, and polity. Kevin Carrico in "Recentering China: The Cantonese in and Beyond the Han" questions a single, unitary Hanness that he believes conceals "countless other perceived and imagined lines of differentiation" (25. The study examines how multiple identities...

  1. Andean region study

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-10-01

    New opportunities for climate change mitigation arising from a higher energy integration among Andean Pact nations were analysed within the framework of the UNEP/GEF Project. Apart from the search for regional mitigation actions, the study was mainly aimed at detecting methodological problems which arise when passing from a strictly national view to the co-ordination of regional actions to deal with climate change. In accordance with the available resources and data, and in view of the mainly methodological nature of the project, it was decided to analyse the opportunities to delve into the energy integration of the Region as regards electricity and natural gas industries and their eventual impact on the emission of greenhouse gases. Although possibilities of setting up electricity and natural gas markets are real, their impacts on GHG emission from the energy system would not prove substantially higher than those which the nations could achieve through the use of their own energy resources, in view that the Andean systems are competitive rather than complementary. More in-depth studies and detail information will be required - unavailable for the present study - to be able to properly evaluate all benefits associated with higher energy integration. Nevertheless, the supply of natural gas to Ecuador seems to be the alternative with the highest impact on GHG emission. If we were to analyse the supply and final consumption of energy jointly, we would most certainly detect additional mitigation options resulting from higher co-operation and co-ordination in the energy field. (EHS)

  2. SEDIMENTATION AND EROSION STUDIES

    Institute of Scientific and Technical Information of China (English)

    Chih Ted YANG

    2005-01-01

    @@ The river systems observed today is the cumulative result of surface, rill, and gully erosion, and sediment transport, scour, and deposition. The divisions of approach between these two related areas are man-made, and are not based on sound science. Most of the erosion studies are done by geologists and agricultural engineers who are concerned of the surface, rill, and gully erosion and the loss of agricultural land productivity. Hydraulic engineers are more interested in the study of sediment transport, scour, and deposition, and their impacts on river engineering and hydraulic structures in rivers and reservoirs. Erosion studies are often based on empirical relationships or field data to determinate the annual sediment yield from a watershed. On the other hand, hydraulic engineers focus their attention on solving equations based on assumed initial and boundary conditions with a time scale of days, hours, or seconds. Both approaches have their complementary strengths and weaknesses. It is important to provide a forum for specialists in both areas to communicate, exchange ideas, and learn from each other.

  3. The safeguards options study

    International Nuclear Information System (INIS)

    The Safeguards Options Study was initiated to aid the International Safeguards Division (ISD) of the DOE Office of Arms Control and Nonproliferation in developing its programs in enhanced international safeguards. The goal was to provide a technical basis for the ISD program in this area. The Safeguards Options Study has been a cooperative effort among ten organizations. These are Argonne National Laboratory, Brookhaven National Laboratory, Idaho National Engineering Laboratory, Lawrence Livermore National Laboratory, Los Alamos National Laboratory, Mound Laboratory, Oak Ridge National Laboratory, Pacific Northwest Laboratories, Sandia National Laboratories, and Special Technologies Laboratory. Much of the Motivation for the Safeguards Options Study is the recognition after the Iraq experience that there are deficiencies in the present approach to international safeguards. While under International Atomic Energy Agency (IAEA) safeguards at their declared facilities, Iraq was able to develop a significant weapons program without being noticed. This is because negotiated safeguards only applied at declared sites. Even so, their nuclear weapons program clearly conflicted with Iraq's obligations under the Nuclear Nonproliferation Treaty (NPT) as a nonnuclear weapon state

  4. The Hi Five study

    DEFF Research Database (Denmark)

    Johansen, Anette; Denbæk, Anne Maj; Bonnesen, Camilla Thørring;

    2015-01-01

    and almost none of them are conducted as randomized controlled trials. The overall aim of the Hi Five study was to develop, implement and evaluate a multi-component school-based intervention to improve hand hygiene and well-being and to reduce the prevalence of infections among school children...... in intervention schools by 20% compared to control schools. This paper describes the development and the evaluation design of Hi Five. METHODS/DESIGN: The Hi Five study was designed as a tree-armed cluster-randomized controlled trial. A national random sample of schools (n = 44) was randomized to one of two...... intervention groups (n = 29) or to a control group with no intervention (n = 15). A total of 8,438 six to fifteen-year-old school children were enrolled in the study. The Hi Five intervention consisted of three components: 1) a curriculum component 2) mandatory daily hand washing before lunch 3) extra cleaning...

  5. Operations dashboard: comparative study

    Science.gov (United States)

    Ramly, Noor Nashriq; Ismail, Ahmad Zuhairi; Aziz, Mohd Haris; Ahmad, Nurul Haszeli

    2011-10-01

    In this present days and age, there are increasing needs for companies to monitor application and infrastructure health. Apart from having proactive measures to secure their application and infrastructure, many see monitoring dashboards as crucial investment in disaster preparedness. As companies struggle to find the best solution to cater for their needs and interest for monitoring their application and infrastructure's health, this paper summarizes the studies made on several known off-the-shelf operations dashboard and in-house developed dashboard. A few criteria of good dashboard are collected from previous studies carried out by several researchers and rank them according to importance and business needs. The finalized criteria that will be discussed in later sections are data visualization, performance indicator, dashboard personalization, audit capability and alert/ notification. Comparative studies between several popular dashboards were then carried out to determine whether they met these criteria that we derived from the first exercise. The findings hopefully can be used to educate and provide an overview of selecting the best IT application and infrastructure operations dashboard that suit business needs, thus become the main contribution of this paper.

  6. The safeguards options study

    Energy Technology Data Exchange (ETDEWEB)

    Hakkila, E.A.; Mullen, M.F.; Olinger, C.T.; Stanbro, W.D. [Los Alamos National Lab., NM (United States); Olsen, A.P.; Roche, C.T.; Rudolph, R.R. [Argonne National Lab., IL (United States); Bieber, A.M.; Lemley, J. [Brookhaven National Lab., Upton, NY (United States); Filby, E. [Idaho National Engineering Lab., Idaho Falls, ID (United States)] [and others

    1995-04-01

    The Safeguards Options Study was initiated to aid the International Safeguards Division (ISD) of the DOE Office of Arms Control and Nonproliferation in developing its programs in enhanced international safeguards. The goal was to provide a technical basis for the ISD program in this area. The Safeguards Options Study has been a cooperative effort among ten organizations. These are Argonne National Laboratory, Brookhaven National Laboratory, Idaho National Engineering Laboratory, Lawrence Livermore National Laboratory, Los Alamos National Laboratory, Mound Laboratory, Oak Ridge National Laboratory, Pacific Northwest Laboratories, Sandia National Laboratories, and Special Technologies Laboratory. Much of the Motivation for the Safeguards Options Study is the recognition after the Iraq experience that there are deficiencies in the present approach to international safeguards. While under International Atomic Energy Agency (IAEA) safeguards at their declared facilities, Iraq was able to develop a significant weapons program without being noticed. This is because negotiated safeguards only applied at declared sites. Even so, their nuclear weapons program clearly conflicted with Iraq`s obligations under the Nuclear Nonproliferation Treaty (NPT) as a nonnuclear weapon state.

  7. Contemplative Media Studies

    Directory of Open Access Journals (Sweden)

    Kevin Healey

    2015-08-01

    Full Text Available The psychological and socio-economic implications of digital technologies call for scholarship that engages questions about the nature of human consciousness, the construction of the self and the ethics of technical development. In this article, I outline a framework for an approach called contemplative media studies. This approach incorporates several different scholarly threads, namely: via critical political-economic media scholarship, a focus on achieving social and economic justice through policy initiatives and structural reform; via media and religious scholarship, an interest in the religious dimensions of digital culture and the role of media in shaping religious identity; and via contemplative studies, an appreciation of the applicability of contemplative principles to research methods and theory. This framework allows us to examine the spiritual ideology that drives the construction of commercial digital platforms and to ask whether alternative platforms might better catalyze human development. Anchored in a critical commitment to socio-economic justice, contemplative media studies is aimed at articulating an ethically-responsive and economically-sustainable architecture of human flourishing.

  8. Celotex (Registered) Replacement Study

    Energy Technology Data Exchange (ETDEWEB)

    Couture, S; Hafner, R

    2002-10-01

    The AL-R8 is the pit storage container in most widespread use at Pantex. The AL-R8 container family consists of standard 20-in.-diameter steel drums, 30 to 60 in. in height, with insulation inserts made of Celotex{reg_sign}--a fiberboard product made from processed sugar cane. Celotex is an acceptable material for inserts in many radioactive material shipping and storage containers. It is a good shock mitigator/insulator, does a fair job in fire protection (when oxygen is excluded), shielding, and criticality, and is inexpensive and easily available. However, the fiberboard absorbs water in humid environments which, when combined with chemical residues in the fiberboard, forms corrosive compounds that can shorten the life of the container and affect container contents. To protect the contents from this potentially damaging environment, the AL-R8 SI was developed to isolate the contents within a sealed stainless steel vessel inside the AL-R8. Although the SI protected the contents, corrosion studies indicated the SI lid bolts might corrode over time and surveillance showed that areas of the outer drum were still subject to corrosion. To address this potential problem, DOE/Albuquerque sponsored bolt and Celotex replacement studies. The bolt replacement study was assigned to Mason and Hanger's Pantex Facility and this Celotex Replacement Study to Lawrence Livermore National Laboratory. The Celotex Replacement Study evaluated options for replacing Celotex with a material that is chemically compatible with the AL-R8 SI container. The evaluation was limited to materials either used previously in nuclear materials shipping and storage containers or materials with known properties in a low-radiation environment. This limitation was set to ensure that the long-term aging effect on the new material is known a priori. Initial material evaluations narrowed the material choices to foam and cork. Although cork performed better than foam in some tests, cork was considered a

  9. Portable treatment systems study

    Energy Technology Data Exchange (ETDEWEB)

    Sherick, M.J.; Schwinkendorf, W.E.; Bechtold, T.E.; Cole, L.T.

    1997-03-01

    In developing their Site Treatment Plans (STPs), many of the Department of Energy installations identified some form of portable treatment, to facilitate compliant disposition of select mixed low-level wastestreams. The Environmental Management Office of Science and Technology requested that a systems study be performed to better define the potential role of portable treatment with respect to mixed low-level waste, highlight obstacles to implementation, and identify opportunities for future research and development emphasis. The study was performed by first establishing a representative set of mixed waste, then formulating portable treatment system concepts to meet the required processing needs for these wastes. The portable systems that were conceptualized were evaluated and compared to a fixed centralized treatment alternative. The system evaluations include a life-cycle cost analysis and an assessment of regulatory, institutional, and technical issues associated with the potential use of portable systems. The results of this study show that when all costs are included, there are no significant cost differences between portable systems and fixed systems. However, it is also emphasized that many uncertainties exist that could impact the cost of implementing portable treatment systems. Portable treatment could be made more attractive through private sector implementation, although there is little economic incentive for a commercial vendor to develop small, specialized treatment capabilities with limited applicability. Alternatively, there may also be valid reasons why fixed units cannot be used for some problematic wastestreams. In any event, there are some site-specific problems that still need to be addressed, and there may be some opportunity for research and development to make a positive impact in these areas.

  10. Portable treatment systems study

    International Nuclear Information System (INIS)

    In developing their Site Treatment Plans (STPs), many of the Department of Energy installations identified some form of portable treatment, to facilitate compliant disposition of select mixed low-level wastestreams. The Environmental Management Office of Science and Technology requested that a systems study be performed to better define the potential role of portable treatment with respect to mixed low-level waste, highlight obstacles to implementation, and identify opportunities for future research and development emphasis. The study was performed by first establishing a representative set of mixed waste, then formulating portable treatment system concepts to meet the required processing needs for these wastes. The portable systems that were conceptualized were evaluated and compared to a fixed centralized treatment alternative. The system evaluations include a life-cycle cost analysis and an assessment of regulatory, institutional, and technical issues associated with the potential use of portable systems. The results of this study show that when all costs are included, there are no significant cost differences between portable systems and fixed systems. However, it is also emphasized that many uncertainties exist that could impact the cost of implementing portable treatment systems. Portable treatment could be made more attractive through private sector implementation, although there is little economic incentive for a commercial vendor to develop small, specialized treatment capabilities with limited applicability. Alternatively, there may also be valid reasons why fixed units cannot be used for some problematic wastestreams. In any event, there are some site-specific problems that still need to be addressed, and there may be some opportunity for research and development to make a positive impact in these areas

  11. [Lichen striatus. Epidemiologic study].

    Science.gov (United States)

    Sittart, J A; Pegas, J R; Sant'Ana, L A; Pires, M C

    1989-01-01

    The authors are showing a retrospective study of 53 cases of lichen striatus concerning sex, colour, age, place of lesions, associated diseases and period of the year of occurrence of the dermatosis. There was a larger number of cases in females of white race and age-between 2 and 5 years old. A greater occurrence was observed in the months of September and March which correspond to spring and summer. Adding the fact that there have been more cases in children, at times in brothers and the trend to spontaneous involution, the authors suggest the possibility of a virus as etiology to this entity. PMID:2666785

  12. IEA studies Middle East

    International Nuclear Information System (INIS)

    Oil production policy in most of the major producing countries of the Middle East looks likely to change as a result of financial constraints and pressures on demand. This -implicitly rather than explicitly - is perhaps the main conclusion to be drawn from the International Energy Agency's (IEA) magisterial study on Middle East oil and gas, in which the production capacities, energy development policies and the structural economic problems of six major oil and gas producers in the region are examined. ''Middle East Oil and Gas'' is available from the IEA/OECD Publications Service. (author)

  13. The DOMUS study protocol

    DEFF Research Database (Denmark)

    Nordly, Mie; Benthien, Kirstine Skov; Von Der Maase, Hans;

    2014-01-01

    is a controlled randomized clinical trial with a balanced parallel-group randomization (1:1). The planned sample size is 340 in- and outpatients treated at the Department of Oncology at Copenhagen University Hospital. Patients are randomly assigned either to: a) standard care plus SPC enriched with a...... cancer can be a powerful tool to improve patients' quality of life and support family/caregivers during the disease trajectory. The present study offers a model for achieving optimal delivery of palliative care in the patient's preferred place of care and attempt to clarify challenges. TRIAL REGISTRATION...

  14. Toxicological study of NTO

    Energy Technology Data Exchange (ETDEWEB)

    London, J.E.; Smith, D.M.

    1985-09-01

    The acute oral LD/sub 50/ values for NTO for mice and rats are greater than 5 g/kg. According to classical guidelines, the test material would be considered only slightly toxic or practically non-toxic in both species. Skin application studies in the rabbit with NTO demonstrated that it was mildly irritating cutaneously. With the scoring scheme, the rabbit eye test was considered negative; however, transient conjunctival and corneal irritation did result from the NTO application in several animals and one developed a chronic anterior uveitis. The material did not induce sensitization in the intradermal guinea pig assay. 6 refs., 1 tab.

  15. Soil organic matter studies

    International Nuclear Information System (INIS)

    A total of 77 papers were presented and discussed during this symposium, 37 are included in this Volume II. The topics covered in this volume include: biochemical transformation of organic matter in soils; bitumens in soil organic matter; characterization of humic acids; carbon dating of organic matter in soils; use of modern techniques in soil organic matter research; use of municipal sludge with special reference to heavy metals constituents, soil nitrogen, and physical and chemical properties of soils; relationship of soil organic matter and plant metabolism; interaction between agrochemicals and organic matter; and peat. Separate entries have been prepared for those 20 papers which discuss the use of nuclear techniques in these studies

  16. STUDYING COMPLEX ADAPTIVE SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    John H. Holland

    2006-01-01

    Complex adaptive systems (cas) - systems that involve many components that adapt or learn as they interact - are at the heart of important contemporary problems. The study of cas poses unique challenges: Some of our most powerful mathematical tools, particularly methods involving fixed points, attractors, and the like, are of limited help in understanding the development of cas. This paper suggests ways to modify research methods and tools, with an emphasis on the role of computer-based models, to increase our understanding of cas.

  17. NOx trade. Case studies

    International Nuclear Information System (INIS)

    Some of the questions with respect to the trade of nitrogen oxides that businesses in the Netherlands have to deal with are dealt with: should a business buy or sell rights for NOx emission; which measures must be taken to reduce NOx emission; how much must be invested; and how to deal with uncertainties with regard to prices. Simulations were carried out with the MOSES model to find the answers to those questions. Results of some case studies are presented, focusing on the chemical sector in the Netherlands. Finally, the financial (dis)advantages of NOx trade and the related uncertainties for a single enterprise are discussed

  18. Fish in Ecotoxicological Studies

    Directory of Open Access Journals (Sweden)

    Vesela Yancheva

    2015-06-01

    Full Text Available Water contamination (heavy metals, pesticides, POPs, etc. is a serious environmental issue which has been raising lots of attention in the last decades because it can destroy aquatic ecosystems and hence, reduce biodiversity. In the field of ecotoxicology it is of main interest to investigate what the effects of organic and inorganic toxicants on different biological organization (cell, tissue, organism, population are. Thus, many authors use different test organisms and particularly, fish. In the current study we aimed to present collected data from the last years which describe why fish is an appropriate species in terms of ecotoxicological research.

  19. Biodistribution studies: General aspects

    International Nuclear Information System (INIS)

    In accordance with the general guidelines for animal experiments, consideration should be given to the appropriateness of experimental procedures, species of animal used, and number of animals required. Biodistribution studies should be performed in a specially reserved area outside the radiopharmaceutical preparation area by staff well trained in the technique. In handling animals for experiments the guidelines issued by national and international agencies should be followed. Even though desirable, it may not be always practical for a small scale radiopharmacy to maintain an animal house. In such a case, cooperation with another institution or agency having appropriate facilities would be required

  20. Sweden's largest Facebook study

    OpenAIRE

    Denti, Leif; Barbopoulus, Isak; Nilsson, Ida; Holmberg, Linda; Thulin, Magdalena; Wendeblad, Malin; Andén, Lisa; Davidsson, Emelie

    2012-01-01

    The emergence of the Internet has made it easier for people to socially interact than ever before. Today, the most popular channel is Facebook with over 845 million users world wide. In Sweden, the number of users amount to approximately half of the population. We had two aims with this study. First, we investigate which areas of Facebook usage that Swedish Facebook users consider more important vis-a-vis less important. We were also interested in how users convey their persona through t... m...