173 research outputs found

    A New Concept for a Laser-Based Ultrasonic Phased Array Receiver Using Photo-emf Detection

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    The virtues of laser-based ultrasound [1], LBU, in general, and phased-array generation and detection in particular, have been appreciated for many years. The ability to improve the spatial resolution of an imaging system, coupled with the potential reduction in local laser intensity at a given location on a component to avoid surface damage while still realizing enhanced performance, represent but two motivating factors that have driven the community to seek methods by which to realize phased-array processing. There has been much activity in demonstrating that phased-array generation of ultrasound can lead to an enhanced directivity of the ultrasound as well as to a decrease (or, increase) in the bandwidth of the generated ultrasound (if desired), be it in the bulk or along the surface of components. Examples of such phased-array generationtechniques (either in the thermoelastic or ablative regimes) include illumination of several discrete spots or locus of points with pulsed lasers [1] on the surface of a workpiece (simultaneously or sequentially), be it a line, an annular ring, or a plurality of spots — or illumination of a scanning pattern of lines along the surface of a sample, the so-called phase-velocity scanning technique [2]. By extension of the phased-array generation concept, one is led to consider the notion of laser-based, phased-array detectionof ultrasound [3]. By reciprocity, this can lead to a receiver of higher resolution relative to a single location for the optical sensing of the ultrasound, as well as to a reduction in the local laser fluence required to achieve a given spatial performance. Moreover, one can, in principle, combine the two modes of phased-array excitation and detection to realize even greater resolution capabilities, which one may refer to as “product processing.” In this case, one has, in essence, a focusing transmitter and an imaging detector, both functioning in concert

    Brain health: time matters in multiple sclerosis

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    publisher: Elsevier articletitle: Brain health: time matters in multiple sclerosis journaltitle: Multiple Sclerosis and Related Disorders articlelink: http://dx.doi.org/10.1016/j.msard.2016.07.003 content_type: article copyright: © 2016 Oxford PharmaGenesis Ltd. Published by Elsevier B.V

    Assessment at Antiretroviral Clinics during TB Treatment Reduces Loss to Follow-Up among HIV-Infected Patients

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    A South African township clinic where loss to follow-up during TB treatment may prevent HIV-infected TB patients from receiving life-saving ART.To determine factors associated with loss to follow-up during TB treatment.Regression analyses of a cohort of ART-eligible TB patients who commenced TB treatment and were followed for 24 weeks.Of 111 ART-eligible TB patients, 15 (14%) died in the ensuing 24 weeks. Of the remaining 96 TB patients, 11 (11%) were lost to follow-up. All TB patients lost to follow-up did not initiate ART. Of 85 TB patients in follow-up, 62 (73%) initiated ART 56 days after TB diagnosis (median, IQR 33-77 days) and 31 days after initial assessment at an ART clinic (median, IQR: 18-55 days). The median duration from TB diagnosis to initial assessment at an ART clinic was 19 days (IQR: 7-48 days). At 24 weeks, 6 of 85 (7%) TB patients who presented to an ART clinic for assessment were lost to follow-up, compared to 5 of 11 (45%) TB patients who did not present to an ART clinic for assessment. Logistic regression analysis (adjusted odds ratio = 0.1, 95% confidence interval [95% CI]: 0.03-0.66) and our Cox proportional hazards model (hazard ratio = 0.2, 95% CI: 0.04-0.68) confirmed that assessment at an ART clinic during TB treatment reduced loss to follow-up.Assessment at antiretroviral clinics for HIV care by trained health-care providers reduces loss to follow-up among HIV-infected patients with TB

    Presentation and Outcome of Tuberculous Meningitis in a High HIV Prevalence Setting

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    Mycobacterium tuberculosis is a common, devastating cause of meningitis in HIV-infected persons. Due to international rollout programs, access to antiretroviral therapy (ART) is increasing globally. Starting patients with HIV-associated tuberculous meningitis (TBM) on ART during tuberculosis (TB) treatment may increase survival in these patients. We undertook this study to describe causes of meningitis at a secondary-level hospital in a high HIV/TB co-infection setting and to determine predictors of mortality in patients with TBM.A retrospective review of cerebrospinal fluid findings and clinical records over a six-month period (March 2009-August 2009). Definite, probable and possible TBM were diagnosed according to published case definitions.TBM was diagnosed in 120/211 patients (57%) with meningitis. In 106 HIV-infected patients with TBM, six-month all-cause mortality was lower in those who received antiretroviral therapy (ART) during TB treatment; hazard ratio = 0.30 (95% CI = 0.08-0.82). Factors associated with inpatient mortality in HIV-infected patients were 1) low CD4(+) count at presentation; adjusted odds ratio (AOR) = 1.4 (95% confidence interval [CI] = 1.03-1.96) per 50 cells/µL drop in CD4(+) count and, 2) higher British Medical Research Council TBM disease grade (2 or 3 versus 1); AOR = 4.8 (95% CI = 1.45-15.87).Starting ART prior to or during TB treatment may be associated with lower mortality in patients with HIV-associated TBM. Advanced HIV and worse stage of TBM disease predict in-hospital mortality in patients presenting with TBM

    Independent prognostic value of angiogenesis and the level of plasminogen activator inhibitor type 1 in breast cancer patients

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    Tumour angiogenesis and the levels of plasminogen activator inhibitor type I (PAI-I) are both informative prognostic markers in breast cancer. In cell cultures and in animal model systems, PAI-I has a proangiogenic effect. To evaluate the interrelationship of angiogenesis and the PAI-I level in breast cancer, we have evaluated the prognostic value of those factors in a total of 228 patients with primary, unilateral, invasive breast cancer, evaluated at a median follow-up time of 12 years. Microvessels were immunohistochemically stained by antibodies against CD34 and quantitated by the Chalkley counting technique. The levels of PAI-I and its target proteinase uPA in tumour extracts were analysed by ELISA. The Chalkley count was not correlated with the levels of uPA or PAI-I. High values of uPA, PAI-I, and Chalkley count were all significantly correlated with a shorter recurrence-free survival and overall survival. In the multivariate analysis, the uPA level did not show independent prognostic impact for any of the analysed end points. In contrast, the risk of recurrence was independently and significantly predicted by both the PAI-I level and the Chalkley count, with a hazard ratio (95% CI) of 1.6 (1.01-2.69) and 1.4 (1.02-1.81), respectively. For overall survival, the Chalkley count, but not PAI-I, was of significant independent prognostic value. The risk of death was 1.7 (1,30-2.15) for Chalkley counts in the upper tertile compared to the lower one. We conclude that the PAI-I level and the Chalkley count are independent prognostic markers for recurrence-free survival in patients with primary breast cancer, suggesting that the prognostic impact of PAI-I is not only based on its involvement in angiogenesis. (C) 2003 Cancer Research UK

    Occurrence and Treatment of Bone Atrophic Non-Unions Investigated by an Integrative Approach

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    Recently developed atrophic non-union models are a good representation of the clinical situation in which many nonunions develop. Based on previous experimental studies with these atrophic non-union models, it was hypothesized that in order to obtain successful fracture healing, blood vessels, growth factors, and (proliferative) precursor cells all need to be present in the callus at the same time. This study uses a combined in vivo-in silico approach to investigate these different aspects (vasculature, growth factors, cell proliferation). The mathematical model, initially developed for the study of normal fracture healing, is able to capture essential aspects of the in vivo atrophic non-union model despite a number of deviations that are mainly due to simplifications in the in silico model. The mathematical model is subsequently used to test possible treatment strategies for atrophic non-unions (i.e. cell transplant at post-osteotomy, week 3). Preliminary in vivo experiments corroborate the numerical predictions. Finally, the mathematical model is applied to explain experimental observations and identify potentially crucial steps in the treatments and can thereby be used to optimize experimental and clinical studies in this area. This study demonstrates the potential of the combined in silico-in vivo approach and its clinical implications for the early treatment of patients with problematic fractures

    Increased expression of urokinase plasminogen activator and its cognate receptor in human seminomas

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    <p>Abstract</p> <p>Background</p> <p>The urokinase plasminogen activating system (uPAS) is implicated in neoplastic progression and high tissue levels of uPAS components correlate with a poor prognosis in different human cancers. Despite that, relative few studies are available on the expression and function of the uPAS components in human seminomas. In the present study we characterized the expression of the urokinase plasminogen activator (uPA), its cognate receptor (uPAR) and the uPA inhibitors PAI-1 and PAI-2 in normal human testis and seminomas.</p> <p>Methods</p> <p>The expression of the above genes was evaluated by means of quantitative RT-PCR, western blot, zymographic analysis and immunohistochemistry.</p> <p>Results</p> <p>Quantitative RT-PCR analysis of 14 seminomas demonstrated that uPA and uPAR mRNAs were, with respect to control tissues, increased in tumor tissues by 3.80 ± 0.74 (p < 0.01) and 6.25 ± 1.18 (p < 0.01) fold, respectively. On the other hand, PAI-1 mRNA level was unchanged (1.02 ± 0.24 fold), while that of PAI-2 was significantly reduced to 0.34 ± 0.18 (p < 0.01) fold. Western blot experiments performed with protein extracts of three seminomas and normal tissues from the same patients showed that uPA protein levels were low or undetectable in normal tissues and induced in tumor tissues. On the same samples, zymographic analysis demonstrated increased uPA activity in tumor tissue extracts. Western blot experiments showed that also the uPAR protein was increased in tumor tissues by 1.83 ± 0.15 fold (p < 0.01). The increased expression of uPA and uPAR was further confirmed by immunohistochemical staining performed in 10 seminomas and autologous uninvolved peritumoral tissues. Finally, variation in the mRNA level of PAI-1 significantly correlated with tumor size.</p> <p>Conclusions</p> <p>We demonstrated the increased expression of uPA and uPAR in human seminomas with respect to normal testis tissues, which may be relevant in testicular cancer progression.</p
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