604 research outputs found

    Patterns and predictors of engagement in peer support among homeless veterans with mental health conditions and substance use histories

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    OBJECTIVES: Patterns and predictors of engagement in peer support services were examined among 50 previously homeless veterans with co-occurring mental health conditions and substance use histories receiving services from the Veterans Health Administration supported housing program. METHOD: Veteran peer specialists were trained to deliver sessions focusing on mental health and substance use recovery to veterans for an intended 1-hr weekly contact over 9 months. Trajectories of peer engagement over the study\u27s duration are summarized. A mixed-effects log-linear model of the rate of peer engagement is tested with three sets of covariates representing characteristics of the veterans. These sets were demographics, mental health and substance use status, and indicators of community participation and support. RESULTS: Data indicate that veterans engaged with peers about once per month rather than the intended once per week. However, frequency of contacts varied greatly. The best predictor of engagement was time, with most contacts occurring within the first 6 months. No other veteran characteristic was a statistically significant predictor of engagement. Older veterans tended to have higher rates of engagement with peer supporters. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: Planners of peer support services could consider yardsticks of monthly services up to 6 months. Peer support services need a flexible strategy with varying levels of intensity according to need. Peer support services will need to be tailored to better engage younger veterans. Future research should consider other sources of variation in engagement with peer support such as characteristics of the peer supporters and service content and setting

    Political brand image: an investigation into the operationalisation of the external orientation of David Cameron’s Conservative brand

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    This paper seeks to address the limited understanding of how to operationalise the external brand image of a political brand. More specifically, this research critically assesses the transfer potential of the six variables of brand image by Bosch, Venter, Han and Boshoff to deconstruct the UK Conservative Party brand from the perspective of young people aged 18–24 years during the 2010 UK General Election campaign. This research demonstrates the applicability of the six variables otherwise known as the ‘brand image framework’ to the political environment. However, the application of the brand image framework in its original conceptualisation proved problematic. Many of the brand image variables were clarified, rearticulated and simplified to address the political context. This refined conceptualisation provided an in-depth understanding of how to investigate the political brand image of David Cameron’s Conservative Party. This study addresses the paucity of research that operationalises external brand image and provides practitioners and academics within and beyond the context of political branding a mechanism to understand the external orientation of brands. This research may also be used by political and non-political brands as a basis to explore external brand image and compare its consistency with internal brand identity

    Political branding: sense of identity or identity crisis? An investigation of the transfer potential of the brand identity prism to the UK Conservative Party

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    Brands are strategic assets and key to achieving a competitive advantage. Brands can be seen as a heuristic device, encapsulating a series of values that enable the consumer to make quick and efficient choices. More recently, the notion of a political brand and the rhetoric of branding have been widely adopted by many political parties as they seek to differentiate themselves, and this has led to an emerging interest in the idea of the political brand. Therefore, this paper examines the UK Conservative Party brand under David Cameron’s leadership and examines the applicability of Kapferer’s brand identity prism to political branding. This paper extends and operationalises the brand identity prism into a ‘political brand identity network’ which identifies the inter-relatedness of the components of the corporate political brand and the candidate political brand. Crucial for practitioners, this model can demonstrate how the brand is presented and communicated to the electorate and serves as a useful mechanism to identify consistency within the corporate and candidate political brands

    Radiofrequency cardiac ablation with catheters placed on opposing sides of the ventricular wall: Computer modelling comparing bipolar and unipolar modes

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    Purpose: The aim of this study was to compare the efficacy of bipolar (BM) vs. unipolar (UM) mode of radiofrequency ablation (RFA) in terms of creating transmural lesions across the interventricular septum (IVS) and ventricular free wall (VFW). Materials and methods: We built computational models to study the temperature distributions and lesion dimensions created by BM and UM on IVS and VFW during RFA. Two different UM types were considered: sequential (SeUM) and simultaneous (SiUM). The effect of ventricular wall thickness, catheter misalignment, epicardial fat, and presence of air in the epicardial space were also studied. Results: Regarding IVS ablation, BM created transmural and symmetrical lesions for wall thicknesses up to 15 mm. SeUM and SiUM were not able to create transmural lesions with IVS thicknesses >= 12.5 and 15 mm, respectively. Lesions were asymmetrical only with SeUM. For VFW ablation, BM also created transmural lesions for wall thicknesses up to 15 mm. However, with SeUM and SiUM transmurality was obtained for VFW thicknesses <= 7.5 and 12.5 mm, respectively. With the three modes, VFW lesions were always asymmetrical. In the scenario with air or a fat tissue layer on the epicardial side, only SiUM was capable of creating transmural lesions. Overall, BM was superior to UM in IVS and VFW ablation when the catheters were not aligned. Conclusions: Our findings suggest that BM is more effective than UM in achieving transmurality across both ventricular sites, except in the situation of the epicardial catheter tip surrounded by air or placed over a fat tissue layer.This work received financial support from the Spanish 'Plan Nacional de I+D+I del Ministerio de Ciencia e Innovacion' (TEC2011-27133-C02-01), and from the Universitat Politecnica de Valencia (PAID-06-11 Ref. 1988). A. Gonzalez-Suarez is the recipient of a Grant VaLi+D (ACIF/2011/194) from the Generalitat Valenciana, Spain. The authors alone are responsible for the content and writing of the paper.González Suárez, A.; Trujillo Guillen, M.; Koruth, J.; D'avila, A.; Berjano, E. (2014). Radiofrequency cardiac ablation with catheters placed on opposing sides of the ventricular wall: Computer modelling comparing bipolar and unipolar modes. International Journal of Hyperthermia. 30(6):372-384. https://doi.org/10.3109/02656736.2014.949878S372384306SIVAGANGABALAN, G., BARRY, M. A., HUANG, K., LU, J., POULIOPOULOS, J., THOMAS, S. P., … KOVOOR, P. (2010). Bipolar Ablation of the Interventricular Septum is More Efficient at Creating a Transmural Line than Sequential Unipolar Ablation. Pacing and Clinical Electrophysiology, 33(1), 16-26. doi:10.1111/j.1540-8159.2009.02602.xNagashima, K., Watanabe, I., Okumura, Y., Ohkubo, K., Kofune, M., Ohya, T., … Hirayama, A. (2011). Lesion Formation by Ventricular Septal Ablation With Irrigated Electrodes. Circulation Journal, 75(3), 565-570. doi:10.1253/circj.cj-10-0870D’ Avila, A., Houghtaling, C., Gutierrez, P., Vragovic, O., Ruskin, J. N., Josephson, M. E., & Reddy, V. Y. (2004). Catheter Ablation of Ventricular Epicardial Tissue. Circulation, 109(19), 2363-2369. doi:10.1161/01.cir.0000128039.87485.0bDukkipati, S. R., d’ Avila, A., Soejima, K., Bala, R., Inada, K., Singh, S., … Reddy, V. Y. (2011). Long-Term Outcomes of Combined Epicardial and Endocardial Ablation of Monomorphic Ventricular Tachycardia Related to Hypertrophic Cardiomyopathy. Circulation: Arrhythmia and Electrophysiology, 4(2), 185-194. doi:10.1161/circep.110.957290Sosa, E., Scanavacca, M., d’ Avila, A., Oliveira, F., & Ramires, J. A. F. (2000). Nonsurgical transthoracic epicardial catheter ablation to treat recurrent ventricular tachycardia occurring late after myocardial infarction. Journal of the American College of Cardiology, 35(6), 1442-1449. doi:10.1016/s0735-1097(00)00606-9Nagashima, K., Watanabe, I., Okumura, Y., Sonoda, K., Kofune, M., Mano, H., … Hirayama, A. (2012). Epicardial Ablation With Irrigated Electrodes. Circulation Journal, 76(2), 322-327. doi:10.1253/circj.cj-11-0984Berjano, E. J. (2006). BioMedical Engineering OnLine, 5(1), 24. doi:10.1186/1475-925x-5-24Abraham, J. P., & Sparrow, E. M. (2007). A thermal-ablation bioheat model including liquid-to-vapor phase change, pressure- and necrosis-dependent perfusion, and moisture-dependent properties. International Journal of Heat and Mass Transfer, 50(13-14), 2537-2544. doi:10.1016/j.ijheatmasstransfer.2006.11.045Jo, B., & Aksan, A. (2010). Prediction of the extent of thermal damage in the cornea during conductive keratoplasty. Journal of Thermal Biology, 35(4), 167-174. doi:10.1016/j.jtherbio.2010.02.004HAINES, D. E., & WATSON, D. D. (1989). Tissue Heating During Radiofrequency Catheter Ablation: A Thermodynamic Model and Observations in Isolated Perfused and Superfused Canine Right Ventricular Free Wall. Pacing and Clinical Electrophysiology, 12(6), 962-976. doi:10.1111/j.1540-8159.1989.tb05034.xZhao, G., Zhang, H.-F., Guo, X.-J., Luo, D.-W., & Gao, D.-Y. (2007). Effect of blood flow and metabolism on multidimensional heat transfer during cryosurgery. Medical Engineering & Physics, 29(2), 205-215. doi:10.1016/j.medengphy.2006.03.005Chang, I. A., & Nguyen, U. D. (2004). BioMedical Engineering OnLine, 3(1), 27. doi:10.1186/1475-925x-3-27Whitney, J., Carswell, W., & Rylander, N. (2013). Arrhenius parameter determination as a function of heating method and cellular microenvironment based on spatial cell viability analysis. International Journal of Hyperthermia, 29(4), 281-295. doi:10.3109/02656736.2013.802375Pearce, J. A. (2013). Comparative analysis of mathematical models of cell death and thermal damage processes. International Journal of Hyperthermia, 29(4), 262-280. doi:10.3109/02656736.2013.786140Doss, J. D. (1982). Calculation of electric fields in conductive media. Medical Physics, 9(4), 566-573. doi:10.1118/1.595107Watanabe, I., Nuo, M., Okumura, Y., Ohkubo, K., Ashino, S., Kofune, M., … Hirayama, A. (2010). Temperature-Controlled Cooled-Tip Radiofrequency Ablation in Left Ventricular Myocardium. International Heart Journal, 51(3), 193-198. doi:10.1536/ihj.51.193Yokoyama, K., Nakagawa, H., Wittkampf, F. H. M., Pitha, J. V., Lazzara, R., & Jackman, W. M. (2006). Comparison of Electrode Cooling Between Internal and Open Irrigation in Radiofrequency Ablation Lesion Depth and Incidence of Thrombus and Steam Pop. Circulation, 113(1), 11-19. doi:10.1161/circulationaha.105.540062Kumar, P., Mounsey, J. P., Gehi, A. K., Schwartz, J. D., & Chung, E. H. (2013). Use of a closed loop irrigated catheter in epicardial ablation of ventricular tachycardia. Journal of Interventional Cardiac Electrophysiology, 38(1), 35-42. doi:10.1007/s10840-013-9799-1Schutt, D., Berjano, E. J., & Haemmerich, D. (2009). Effect of electrode thermal conductivity in cardiac radiofrequency catheter ablation: A computational modeling study. International Journal of Hyperthermia, 25(2), 99-107. doi:10.1080/02656730802563051Gopalakrishnan, J. (2002). A Mathematical Model for Irrigated Epicardial Radiofrequency Ablation. Annals of Biomedical Engineering, 30(7), 884-893. doi:10.1114/1.1507845Suárez, A. G., Hornero, F., & Berjano, E. J. (2010). Mathematical Modeling of Epicardial RF Ablation of Atrial Tissue with Overlying Epicardial Fat. The Open Biomedical Engineering Journal, 4(1), 47-55. doi:10.2174/1874120701004020047Haemmerich, D., Chachati, L., Wright, A. S., Mahvi, D. M., Lee, F. T., & Webster, J. G. (2003). Hepatic radiofrequency ablation with internally cooled probes: effect of coolant temperature on lesion size. IEEE Transactions on Biomedical Engineering, 50(4), 493-500. doi:10.1109/tbme.2003.809488Koruth, J. S., Dukkipati, S., Miller, M. A., Neuzil, P., d’ Avila, A., & Reddy, V. Y. (2012). Bipolar irrigated radiofrequency ablation: A therapeutic option for refractory intramural atrial and ventricular tachycardia circuits. Heart Rhythm, 9(12), 1932-1941. doi:10.1016/j.hrthm.2012.08.001González-Suárez, A., Trujillo, M., Burdío, F., Andaluz, A., & Berjano, E. (2012). Feasibility study of an internally cooled bipolar applicator for RF coagulation of hepatic tissue: Experimental and computational study. International Journal of Hyperthermia, 28(7), 663-673. doi:10.3109/02656736.2012.716900Agah, R., Gandjbakhche, A. H., Motamedi, M., Nossal, R., & Bonner, R. F. (1996). Dynamics of temperature dependent optical properties of tissue: dependence on thermally induced alteration. IEEE Transactions on Biomedical Engineering, 43(8), 839-846. doi:10.1109/10.508546Haines, D. E. (2011). 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    Mathematical Modeling of Epicardial RF Ablation of Atrial Tissue with Overlying Epicardial Fat

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    The efficacy of treating atrial fibrillation by RF ablation on the epicardial surface is currently under question due to the presence of epicardial adipose tissue interposed between the ablation electrode and target site (atrial wall). The problem is probably caused by the electrical conductivity of the fat (0.02 S/m) being lower than that of the atrial tissue (0.4-0.6 S/m). Since our objective is to improve epicardial RF ablation techniques, we planned a study based on a two-dimensional mathematical model including an active electrode, a fragment of epicardial fat over a fragment of atrial tissue, and a section of atrium with circulating blood. Different procedures for applying RF power were studied, such as varying the frequency, using a cooled instead of a dry electrode, and different modes of controlling RF power (constant current, temperature and voltage) for different values of epicardial fat thickness. In general, the results showed that the epicardial fat layer seriously impedes the passage of RF current, thus reducing the effectiveness of atrial wall RF ablation

    NuSTAR and Chandra observations of new X-ray transients in the central parsec of the Galaxy

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    We report NuSTAR and Chandra observations of two X-ray transients, SWIFT J174540.7−-290015 (T15) and SWIFT J174540.2−-290037 (T37), which were discovered by the Neil Gehrels Swift Observatory in 2016 within r∼1r\sim1 pc of Sgr A*. NuSTAR detected bright X-ray outbursts from T15 and T37, likely in the soft and hard states, with 3-79~keV luminosities of 8×10368\times10^{36} and 3×10373\times10^{37} erg/s, respectively. No X-ray outbursts have previously been detected from the two transients and our Chandra ACIS analysis puts an upper limit of LX≲2×1031L_X \lesssim 2 \times10^{31} erg/s on their quiescent 2-8 keV luminosities. No pulsations, significant QPOs, or type I X-ray bursts were detected in the NuSTAR data. While T15 exhibited no significant red noise, the T37 power density spectra are well characterized by three Lorentzian components. The declining variability of T37 above ν∼10\nu \sim 10 Hz is typical of black hole (BH) transients in the hard state. NuSTAR spectra of both transients exhibit a thermal disk blackbody, X-ray reflection with broadened Fe atomic features, and a continuum component well described by Comptonization models. Their X-ray reflection spectra are most consistent with high BH spin (a∗≳0.9a_{*} \gtrsim 0.9) and large disk density (ne∼1021n_e\sim10^{21} cm−3^{-3}). Based on the best-fit ionization parameters and disk densities, we found that X-ray reflection occurred near the inner disk radius, which was derived from the relativistic broadening and thermal disk component. These X-ray characteristics suggest the outbursting BH-LMXB scenario for both transients and yield the first BH spin measurements from X-ray transients in the central 100 pc region.Comment: 15 pages, 7 figures, accepted for publication in Ap

    Insulin-like growth factor-binding protein-2 promotes prostate cancer cell growth via IGF-dependent or -independent mechanisms and reduces the efficacy of docetaxel

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    Background: The development of androgen independence, chemo-, and radioresistance are critical markers of prostate cancer progression and the predominant reasons for its high mortality. Understanding the resistance to therapy could aid the development of more effective treatments. Aim: The aim of this study is to investigate the effects of insulin-like growth factor-binding protein-2 (IGFBP-2) on prostate cancer cell proliferation and its effects on the response to docetaxel. Methods: DU145 and PC3 cells were treated with IGFBP-2, insulin-like growth factor I (IGF-I) alone or in combination with blockade of the IGF-I receptor or integrin receptors. Cells were also treated with IGFBP-2 short interfering ribonucleic acid with or without a PTEN (phosphatase and tensin homologue deleted on chromosome 10) inhibitor or docetaxel. Tritiated thymidine incorporation was used to measure cell proliferation and Trypan blue cell counting for cell death. Levels of IGFBP-2 mRNA were measured using RT-PCR. Abundance and phosphorylation of proteins were assessed using western immunoblotting. Results: The IGFBP-2 promoted cell growth in both cell lines but with PC3 cells this was in an IGF-dependent manner, whereas with DU145 cells the effect was independent of IGF receptor activation. This IGF-independent effect of IGFBP-2 was mediated by interaction with β-1-containing integrins and a consequent increase in PTEN phosphorylation. We also determined that silencing IGFBP-2 in both cell lines increased the sensitivity of the cells to docetaxel. Conclusion: The IGFBP-2 has a key role in the growth of prostate cancer cells, and silencing IGFBP-2 expression reduced the resistance of these cells to docetaxel. Targeting IGFBP-2 may increase the efficacy of docetaxel.7 page(s
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