It takes a village to break up a match: a systemic analysis of formal youth mentoring relationship endings

BACKGROUND Although early closure of formal youth mentoring relationships has recently begun to receive some attention, more information about factors that contribute to premature endings, and how those factors interact, is needed so that empirically-based program practices can be developed and disseminated to prevent such endings and to ensure that youth reap the benefits mentoring can provide. OBJECTIVE This qualitative interview study applies a systemic model of youth mentoring relationships (Keller in J Prim Prev 26:169–188, 2005a) to the study of mentoring relationship endings in community-based mentoring matches to understand why these matches ended. METHOD Mentors, parents/guardians and program staff associated with 36 mentoring matches that had ended were interviewed about their experiences of these relationships and their understanding of why they had ended. Thematic analysis of the interview transcripts and mentoring program case notes for each match followed by systemic modeling of the relationships yielded three major findings. RESULTS A strong mentor–youth relationship is necessary but not sufficient for match longevity. The mentor–youth relationship, even when relatively strong, is unlikely to withstand disruptions in other relationships in the system. Agency contextual factors, such as program practices and policies and staffing patterns, have a critical role to play in sustaining mentoring matches, as they directly influence all of the relationships in the mentoring system. CONCLUSION These findings highlight the importance of considering not just the mentoring dyad but also the parent/guardian and program context when trying to prevent match closures. They also point to several program practices that may support longer mentoring relationships.Accepted manuscrip

Optimal MRI sequences for 68Ga-PSMA-11 PET/MRI in evaluation of biochemically recurrent prostate cancer.

BackgroundPET/MRI can be used for the detection of disease in biochemical recurrence (BCR) patients imaged with 68Ga-PSMA-11 PET. This study was designed to determine the optimal MRI sequences to localize positive findings on 68Ga-PSMA-11 PET of patients with BCR after definitive therapy. Fifty-five consecutive prostate cancer patients with BCR imaged with 68Ga-PSMA-11 3.0T PET/MRI were retrospectively analyzed. Mean PSA was 7.9 ± 12.9 ng/ml, and mean PSA doubling time was 7.1 ± 6.6 months. Detection rates of anatomic correlates for prostate-specific membrane antigen (PSMA)-positive foci were evaluated on small field of view (FOV) T2, T1 post-contrast, and diffusion-weighted images. For prostate bed recurrences, the detection rate of dynamic contrast-enhanced (DCE) imaging for PSMA-positive foci was evaluated. Finally, the detection sensitivity for PSMA-avid foci on 3- and 8-min PET acquisitions was compared.ResultsPSMA-positive foci were detected in 89.1% (49/55) of patients evaluated. Small FOV T2 performed best for lymph nodes and detected correlates for all PSMA-avid lymph nodes. DCE imaging performed the best for suspected prostate bed recurrence, detecting correlates for 87.5% (14/16) of PSMA-positive prostate bed foci. The 8-min PET acquisition performed better than the 3-min acquisition for lymph nodes smaller than 1 cm, detecting 100% (57/57) of lymph nodes less than 1 cm, compared to 78.9% (45/57) for the 3-min acquisition.ConclusionPSMA PET/MRI performed well for the detection of sites of suspected recurrent disease in patients with BCR. Of the MRI sequences obtained for localization, small FOV T2 images detected the greatest proportion of PSMA-positive abdominopelvic lymph nodes and DCE imaging detected the greatest proportion of PSMA-positive prostate bed foci. The 8-min PET acquisition was superior to the 3 min acquisition for detection of small lymph nodes

Steady-state activation and modulation of the synaptic-type α1β2γ2L GABAA receptor by combinations of physiological and clinical ligands

The synaptic α1β2γ2 GAB

Fluid dynamics of biological and mechanical olfaction

The sense of smell is critical to a number of animals, from moths all the way to the largest mammal on land, the elephant. Despite these animals ranging across eight orders of magnitude in body mass, there are commonalities in their methods for bringing odor molecules to their sensors. Understanding the olfaction of animals can also inspire the design of autonomous smelling machines, which are currently limited in their speed and sensitivity. Most previous work on olfaction has focused on the neuroscience of animal olfaction or the algorithms involved in processing data from machine olfaction. In this dissertation, we focus on the fluid mechanics of olfaction. We used a combined experimental and theoretical approach, with particular emphasis on building machines that can mimic the olfaction of animals. We show that many animals have a hierarchical structure to their olfaction systems, either antenna or nasal cavities, that increase their surface area to improve the chance of odor deposition. Animals optimize their olfaction with behaviors varying from sniffing to angling their antenna obliquely to the wind. Both methods slow down the air near the sensing surfaces, which increases the number of molecules that can deposit by diffusion.Ph.D