Struvite formation associated with the microalgae biofilm matrix of a rotating algal biofilm reactor (RABR) during nutrient removal from municipal wastewater.

Struvite was observed within the microalgae biofilm matrix of an outdoor, pilot-scale rotating algal biofilm reactor (RABR) designed to remove nitrogen and phosphorus from municipal anaerobic digester filtrate. The bottom layer of cells (2.5-month growth) and two top layers of cells (1-week and 2.5-month growth) were evaluated on east- and west-facing sides of the RABR. Sun orientation and shading effects of upper biofilm layers impacted the species composition and microalgae content of the bottom biofilm layers. Struvite formed within the microalgae biofilm matrix, and a higher struvite content appeared to be correlated with a higher microalgae content. The highest struvite content (expressed as %wt. of total solids) was observed in the east- and west-facing bottom layers of growth and west-facing 1-week growth (5.0%, 4.3%, and 4.1%, respectively). The lowest struvite content was observed in east- and west-facing 2.5-month growth and east-facing 1-week growth (1.1%, 1.5%, and 1.1%, respectively). Despite RABR influent component ion molar ratios with potential for various magnesium and calcium precipitates, microalgae biofilm provided pH and nucleation sites favorable to struvite precipitation. This evaluation is the first in the refereed literature the authors are aware of that reports on the association of struvite formation in the presence of a microalgae biofilm.

The effect of vasoactive agents on post-pressure hyperemia.

The cutaneous hyperemic response following the release of direct pressure occlusion lasts much longer than the short-term hyperemia that occurs after proximal arterial occlusion. Post-pressure hyperemia may be an important mechanism to prevent pressure induced injury to the skin. The role of vasoactive mediators in modulating post-pressure hyperemia is unknown. In an effort to better understand this phenomenon, we performed an initial study using microdialysis infusion to measure the effect of several known mediators of vascular response on post-pressure hyperemia. A vise clamp was used to apply direct occlusive pressure to a laser Doppler sensor on the skin surface overlying the microdialysis fiber. Skin blood flow was measured continuously pre, during and post-occlusion while infusing the vasoactive substance or control phosphate buffer. Angiotensin II, Calcitonin gene related peptide and histamine had minimal effect on post pressure blood flow. Conversely, prostaglandin E1, prostaglandin E2, and L-NAME diminished the early phase of the post-occlusion hyperemic response. Perhaps the most profound effect we observed was the decrease in post-occlusive blood flow due to administration of epinephrine, dopamine and prostaglandin F2alpha. In contrast, adenosine and caffeine augmented blood flow post occlusion. In this initial survey study, we have demonstrated differential effects of various vascular mediators on the post-pressure hyperemic phenomenon. Our findings may lead to the development of agents to prevent pressure sores by augmenting the skin blood flow response to locally applied pressure.

All aboard: users' experiences of adapted paddling programs.

PURPOSE: Research has yet to examine the experiences of paddle boarders, or of kayakers with disabilities other than spinal cord injuries. The goal of this study was to explore the experiences of kayakers and paddle boarders in two adaptive paddling programs. METHOD: Participants were children and adults requiring physical, cognitive, and/or psychosocial supports. Using an ethnographic approach, participant observations (n = 24) and semi-structured interviews (n = 11) were completed. Data were analyzed thematically. RESULT: We identified three main themes. "Different Strokes" described the personal meaning participants ascribed to aspects of paddling, including valuing fun, exercise and relaxation. "Turning the Tide" illustrated the process of becoming a paddler, from doubting capacity to feeling competent. "Headwinds" explored paddlers' interactions with the broader social, institutional, and economic environments, such as inadequate funding and program aversion to risk. CONCLUSIONS: Programs offering a variety of adaptive paddle boarding and kayaking configurations enable paddlers to make valued choices about their participation. In addition to providing equipment and support to meet paddlers' functional abilities, program developers and clinicians should also consider individual preferences for exercise, socialization, risk taking, self-presentation of disability, and independence.IMPLICATIONS FOR REHABILITATIONPeople living with physical, cognitive, and/or psychosocial impairments perceive kayaking and paddle boarding as meaningful activities offering opportunities to exercise, have fun, achieve goals, socialize, and/or relax on the water.Kayakers and paddle boarders value equipment options that meet their physical and disability-disclosure preferences.Despite the existence of adaptive paddling programs, participation may be restricted by program availability, risk management policies, and leisure funding.