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High Positive (high + positive)

Distribution by Scientific Domains
Medical Sciences75%

Terms modified by High Positive

  • high positive correlation
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  • high positive end-expiratory pressure
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  • high positive predictive value
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    Selected Abstracts

    Fatigue of Lead Zirconate Titanate Ceramics II: Sesquipolar Loading

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2007
    Nina Balke
    Piezoelectric actuators generally are driven with unipolar electric load cycles. Although the obtainable strain is increased by small excursions into the negative field regime, this type of load cycle is rarely considered, as its long-time reliability has been questioned. Here, we investigate the degradation of lead zirconate titanate during cycling between high positive and low negative electric fields. Measurements of the large and small signal parameters are used to quantify changes of the material. The fatigue behavior shifts from one best described with existing models of unipolar fatigue to bipolar-like fatigue with increasing field amplitude. [source]

    Role of pleural viscosity in the differential diagnosis of exudative pleural effusion

    RESPIROLOGY, Issue 2 2007
    Ozkan YETKIN
    Objective and background: Determining the aetiology of an effusion involves assessing if it is an exudate or a transudate. However, a reliable test for determining the aetiology of a pleural effusion is lacking. Pleural viscosity has a high sensitivity and specificity and a high positive and negative predictive value for discriminating exudative and transudative pleural effusions. The aim of this study was to use pleural fluid viscosity to discriminate between various aetiologies of exudative effusions, namely malignant, parapneumonic and tuberculous. Methods: Seventy consecutive patients (24 women, 46 men, mean age = 67 years) with exudative pleural effusion due to pneumoniae in 24 patients, tuberculous pleurisy in 21 and lung cancer in 25 were studied prospectively. Measurements of pleural fluid and plasma viscosity were performed using Brookfield DV-II viscometer. Results: Pleural viscosity and pleural LDH were highest in the tuberculous pleurisy patients and lowest in the lung cancer patients. Pleural viscosity ,1.57 was found to be indicative of tuberculous pleurisy with a sensitivity of 100% and specificity of 95%. Pleural viscosity <1.39 was found to be indicative of lung cancer with a sensitivity of 100% and specificity of 94%. Pleural viscosity was significantly correlated with pleural albumin (r = 0.34, P = 0.004), protein (r = 0.40, P = 0.001), LDH (r = 0.70, P < 0.001) and plasma viscosity (r = 0.44, P < 0.001), having the most significant value with pleural LDH. Conclusion: The pleural fluid viscosity of patients with parapneumonic, tuberculous and malignant effusions are significantly different from each other. Among these groups, tuberculous effusions had the highest viscosity, and malignant effusions from lung cancer the lowest. [source]

    Diagnosis of common dermatophyte infections by a novel multiplex real-time polymerase chain reaction detection/identification scheme

    BRITISH JOURNAL OF DERMATOLOGY, Issue 4 2007
    M. Arabatzis
    Summary Background, In the absence of a functional dermatophyte-specific polymerase chain reaction (PCR), current diagnosis of dermatophytoses, which constitute the commonest communicable diseases worldwide, relies on microscopy and culture. This combination of techniques is time-consuming and notoriously low in sensitivity. Objectives, Recent dermatophyte gene sequence records were used to design a real-time PCR assay for detection and identification of dermatophytes in clinical specimens in less than 24 h. Patients and methods, Two assays based on amplification of ribosomal internal transcribed spacer regions and on the use of probes specific to relevant species and species-complexes were designed, optimised and clinically evaluated. One assay was for detecting the Trichophyton mentagrophytes species complex plus T. tonsurans and T. violaceum. The second assayed for the T. rubrum species complex, Microsporum canis and M. audouinii. Results, The analytical sensitivity of both assays was 0·1 pg DNA per reaction, corresponding to 2·5,3·3 genomes per sample. The protocol was clinically evaluated over 6 months by testing 92 skin, nail and hair specimens from 67 patients with suspected dermatophytosis. Real-time PCR detected and correctly identified the causal agent in specimens from which T. rubrum, T. interdigitale, M. audouinii or T. violaceum grew in culture, and also identified a dermatophyte species in an additional seven specimens that were negative in microscopy and culture. Conclusions, This highly sensitive assay also proved to have high positive and negative predictive values (95·7% and 100%), facilitating the accurate, rapid diagnosis conducive to targeted rather than empirical therapy for dermatophytoses. [source]

    Procalcitonin-reduced sensitivity and specificity in heavily leucopenic and immunosuppressed patients

    BRITISH JOURNAL OF HAEMATOLOGY, Issue 1 2001
    M. Svaldi
    Procalcitonin (PCT) has proven to be a very sensitive marker of sepsis for non-leucopenic patients. Little is known about its relevance in immunosuppressed and leucopenic adults. Four hundred and seventy-five PCT determinations were carried out in 73 haematological patients: on 221 occasions the white blood cell (WBC) count was <,1·0 × 109/l and on 239 occasions it was >,1·0 × 109/l leucocytes. Patients were classified as: non-systemic infected controls (n = 280), patients with bacteraemia (n = 32), sepsis (n = 30), severe sepsis (n = 3), septic shock (n = 3) and systemic inflammatory response syndrome (SIRS) (n = 62). When the WBC count was >,1·0 × 109/l, gram-negative bacteria induced higher PCT levels (median 9·4 ng/ml) than gram-positives (median 1·4 ng/ml). In cases with a WBC <,1·0 × 109/l, PCT levels were similar for gram-negative and gram-positive bacteria (1·1 ng/ml versus 0·85 ng/ml). Regardless of the leucocyte count, the median PCT level in bacteraemia cases always remained <,0·5 ng/ml. In heavily leucopenic situations, PCT levels were never >,2 ng/ml even in the sepsis and severe sepsis/septic shock groups, whereas a WBC count >,1·0 × 109/l resulted in median PCT values of 4·1 ng/ml and 45 ng/ml respectively. The positive predictive value for sepsis (cut-off 2 ng/ml) was 93% in cases of WBC count >,1·0 × 109/l, but only 66% in leucopenic conditions. The negative predictive value (cut-off 0·5 ng/ml) was 90% when the WBC count was >,1·0 × 109/l and 63% in leucopenic conditions. Procalcitonin is an excellent sepsis marker with a high positive- and negative-predictive value in patients with WBC count >,1·0 × 109/l, but it does not work satisfactorily below this leucocyte count. [source]