1,793 research outputs found

    Charge Symmetry Violation Effects in Pion Scattering off the Deuteron

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    We discuss the theoretical and experimental situations for charge symmetry violation (CSV) effects in the elastic scattering of pi+ and pi- on deuterium (D) and 3He/3H. Accurate comparison of data for both types of targets provides evidence for the presence of CSV effects. While there are indications of a CSV effect in deuterium, it is much more pronounced in the case of 3He/3H. We provide a description of the CSV effect on the deuteron in terms of single- and double- scattering amplitudes. The Delta-mass splitting is taken into account. Theoretical predictions are compared with existing experimental data for pi-d scattering; a future article will speak to the pi-three nucleon case.Comment: 16 pages of RevTeX, 7 postscript figure

    The development of advanced practice roles: implications in the international nursing community

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    This article examined the critical elements that have been identified in the development of advanced practice roles of nurses in four countries: Brazil, Thailand, the United Kingdom and the United States of America. Several socio-political and professional forces were examined for possible insights and ways in which they may have shaped the development and evolution of the roles of advanced practice nurses (APNs). These forces were: the socio-political environment; the health needs of society; the health workforce supply and demand; governmental policy and support; intra- and interprofessional collaboration; the development of nursing education; and documentation of effectiveness of the advanced role. The development of APN roles in the four social systems was reviewed to illustrate how socio-political and professional forces may have shaped nursing roles in each health care delivery system. Commonalities and distinguishing features across the four health and social systems were analysed to assess the predictive forces that may be identified as advanced roles in nursing have evolved in the global community.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74797/1/j.1466-7657.2001.00065.x.pd

    Differentiation of Prostate Cancer from Normal Tissue in Radical Prostatectomy Specimens by Desorption Electrospray Ionization and Touch Spray Ionization Mass Spectrometry.

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    Radical prostatectomy is a common treatment option for prostate cancer before it has spread beyond the prostate. Examination for surgical margins is performed post-operatively with positive margins reported to occur in 6.5 – 32% of cases. Rapid identification of cancerous tissue during surgery could improve surgical resection. Desorption electrospray ionization (DESI) is an ambient ionization method which produces mass spectra dominated by lipid signals directly from prostate tissue. With the use of multivariate statistics, these mass spectra can be used to differentiate cancerous and normal tissue. The method was applied to 100 samples from 12 human patients to create a training set of MS data. The quality of the discrimination achieved was evaluated using principal component analysis - linear discriminant analysis (PCA-LDA) and confirmed by histopathology. Cross validation (PCA-LDA) showed >95% accuracy. An even faster and more convenient method, touch spray (TS) mass spectrometry, not previously tested to differentiate diseased tissue, was also evaluated by building a similar MS data base characteristic of tumor and normal tissue. An independent set of 70 non-targeted biopsies from six patients was then used to record lipid profile data resulting in 110 data points for an evaluation dataset for TS-MS. This method gave prediction success rates measured against histopathology of 93%. These results suggest that DESI and TS could be useful in differentiating tumor and normal prostate tissue at surgical margins and that these methods should be evaluated intra-operatively

    Oncologic outcomes and prognostic impact of urothelial recurrences in patients undergoing segmental and total ureterectomy for upper tract urothelial carcinoma

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    INTRODUCTION: We evaluated the impact of urothelial recurrences in a cohort of patients undergoing segmental (SU) and total ureterectomy (TU) as an alternative to nephroureterectomy (NU) for upper tract urothelial carcinoma. METHODS: Between 1999 and 2012, patients who underwent SU, TU and NU for treatment of upper tract urothelial carcinoma were evaluated. Demographic, surgical, pathologic and oncologic data were collected. Recurrence-free (RFS) and disease-specific survival (DSS) were analyzed using Kaplan-Meier and multivariable Cox methods. RESULTS: A total 141 patients were evaluated, 35 underwent SU, 10 TU and 96 NU. Patients who underwent TU were more likely to have bilateral disease (p < 0.01), solitary kidney (p < 0.01), and multifocal disease (p = 0.01). Organ-confined (p < 0.01) and low-grade disease (p < 0.01) were more common in the TU and SU groups compared with NU. At a median follow-up of 56.9 months (range: 0.2-181.1) disease relapse occurred in 88 (55.3%) patients. Localized recurrence occurred in 31.1% of SU/TU group compared to 27.1% (p = 0.62) of the NU group. Neither total nor segmental ureterectomy demonstrated significantly worse RFS (p = 0.26 and p = 0.81), CSS (p = 0.96 and p = 0.52) or overall survival (p = 0.59 and p = 0.55) compared with complete NU. Localized urothelial recurrence did not confer increased risk of cancer-specific (p = 0.73) or overall mortality (p = 0.39). The paper's most important limitations include its retrospective nature and its relatively small number of patients. CONCLUSION: No significant survival differences were demonstrated between surgical approaches for upper tract urothelial cancer. Localized urothelial recurrence after surgical treatment for upper tract urothelial cancer does not affect mortality in this population. TU with ileal-substitution may provide an alternative option for patients with extensive ureteral disease and poor renal function

    Ambient ionization mass spectrometric analysis of human surgical specimens to distinguish renal cell carcinoma from healthy renal tissue

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    Touch spray - mass spectrometry (TS-MS) is an ambient ionization technique (ionization of unprocessed samples in the open air) that may find intraoperative applications in quickly identifying the disease state of cancerous tissues and in defining surgical margins. In this study, TS-MS was performed on fresh kidney tissue (~1–5 cm3), within one hour of resection, from 21 human subjects afflicted by renal cell carcinoma (RCC). The preliminary diagnostic value of TS-MS data taken from freshly resected tissue was evaluated. Principal component analysis (PCA) of the negative ion mode (m/z 700–1000) data provided separation between RCC (16 samples) and healthy renal tissue (13 samples). Linear discriminant analysis (LDA) on the PCA compressed data estimated sensitivity (true positive rate) and specificity (true negative rate) of 98% and 95%, respectively, based on histopathological evaluation. The results indicate that TS-MS might provide rapid diagnostic information in spite of the complexity of unprocessed kidney tissue and the presence of interferences such as urine and blood. Desorption electrospray ionization imaging (DESI-MSI) in the negative ionization mode was performed on the tissue specimens after TS-MS analysis as a reference method. The DESI imaging experiments provided phospholipid profiles (m/z 700–1000) that also separated RCC and healthy tissue in the PCA space, with PCA-LDA sensitivity and specificity of 100% and 89%, respectively. The TS and DESI loading plots indicated that different ions contributed most to the separation of RCC from healthy renal tissue (m/z 794 [PC 34:1+Cl]− and 844 [PC 38:4+Cl]− for TS vs. m/z 788 [PS 36:1-H]− and 810 [PS 38:4-H]− for DESI), while m/z 885 ([PI 38:4-H]−) was important in both TS and DESI. The prospect, remaining hurdles, and future work required for translating TS-MS into a method of intraoperative tissue diagnosis is discussed.

    TeV Observations of the Variability and Spectrum of Markarian 501

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    Markarian 501 is only the second extragalactic source to be detected with high statistical certainty at TeV energies; it is similar in many ways to Markarian 421. The Whipple Observatory gamma-ray telescope has been used to observe the AGN Markarian 501 in 1996 and 1997, the years subsequent to its initial detection. The apparent variability on the one-day time-scale observed in TeV gamma rays in 1995 is confirmed and compared with the variability in Markarian 421. Observations at X-ray and optical wavelengths from 1997 are also presented.Comment: 4 pages, 2 figures, to appear in proceedings of 25th ICRC (Durban
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