Probing Cellular Dynamics with a Chemical Signal Generator

Observations of material and cellular systems in response to time-varying chemical stimuli can aid the analysis of dynamic processes. We describe a microfluidic “chemical signal generator,” a technique to apply continuously varying chemical concentration waveforms to arbitrary locations in a microfluidic channel through feedback control of the interface between parallel laminar (co-flowing) streams. As the flow rates of the streams are adjusted, the channel walls are exposed to a chemical environment that shifts between the individual streams. This approach can be used to probe the dynamic behavior of objects or substances adherent to the interior of the channel. To demonstrate the technique, we exposed live fibroblast cells to ionomycin, a membrane-permeable calcium ionophore, while assaying cytosolic calcium concentration. Through the manipulation of the laminar flow interface, we exposed the cells' endogenous calcium handling machinery to spatially-contained discrete and oscillatory intracellular disturbances, which were observed to elicit a regulatory response. The spatiotemporal precision of the generated signals opens avenues to previously unapproachable areas for potential investigation of cell signaling and material behavior

The Relative Merits of Posterior Surgical Treatments for Multi-Level Degenerative Cervical Myelopathy Remain Uncertain: Findings from a Systematic Review.

OBJECTIVES: To assess the reporting of study design and characteristics in multi-level degenerative cervical myelopathy (DCM) treated by posterior surgical approaches, and perform a comparison of clinical and radiographic outcomes between different approaches. METHODS: A literature search was performed in Embase and MEDLINE between 1995-2019 using a sensitive search string combination. Studies were selected by predefined selection criteria: Full text articles in English, with >10 patients (prospective) or >50 patients (retrospective), reporting outcomes of multi-level DCM treated by posterior surgical approach. RESULTS: A total of 75 studies involving 19,510 patients, conducted worldwide, were identified. Laminoplasty was described in 56 studies (75%), followed by laminectomy with (36%) and without fusion (16%). The majority of studies were conducted in Asia (84%), in the period of 2016-2019 (51%), of which laminoplasty was studied predominantly. Twelve (16%) prospective studies and 63 (84%) retrospective studies were identified. The vast majority of studies were conducted in a single centre (95%) with clear inclusion/exclusion criteria and explicit cause of DCM. Eleven studies (15%) included patients with ossification of the posterior longitudinal ligament exclusively with cohorts of 57 to 252. The clinical and radiographic outcomes were reported with heterogeneity when comparing laminoplasty, laminectomy with and without fusion. CONCLUSIONS: Heterogeneity in the reporting of study and sample characteristics exists, as well as in clinical and radiographic outcomes, with a paucity of studies with a higher level of evidence. Future studies are needed to elucidate the clinical effectiveness of posterior surgical treatments

Food System Resilience: Concepts, Issues, and Challenges

Food system resilience has multiple dimensions. We draw on food system and resilience concepts and review resilience framings of different communities. We present four questions to frame food system resilience (Resilience of what? Resilience to what? Resilience from whose perspective? Resilience for how long?) and three approaches to enhancing resilience (robustness, recovery, and reorientation—the three “Rs”). We focus on enhancing resilience of food system outcomes and argue this will require food system actors adapting their activities, noting that activities do not change spontaneously but in response to a change in drivers: an opportunity or a threat. However, operationalizing resilience enhancement involves normative choices and will result in decisions having to be negotiated about trade-offs among food system outcomes for different stakeholders. New approaches to including different food system actors’ perceptions and goals are needed to build food systems that are better positioned to address challenges of the future

Molecular imaging of inflammation and intraplaque vasa vasorum: A step forward to identification of vulnerable plaques?

Current developments in cardiovascular biology and imaging enable the noninvasive molecular evaluation of atherosclerotic vascular disease. Intraplaque neovascularization sprouting from the adventitial vasa vasorum has been identified as an independent predictor of intraplaque hemorrhage and plaque rupture. These intraplaque vasa vasorum result from angiogenesis, most likely under influence of hypoxic and inflammatory stimuli. Several molecular imaging techniques are currently available. Most experience has been obtained with molecular imaging using positron emission tomography and single photon emission computed tomography. Recently, the development of targeted contrast agents has allowed molecular imaging with magnetic resonance imaging, ultrasound and computed tomography. The present review discusses the use of these molecular imaging techniques to identify inflammation and intraplaque vasa vasorum to identify vulnerable atherosclerotic plaques at risk of rupture and thrombosis. The available literature on molecular imaging techniques and molecular targets associated with inflammation and angiogenesis is discussed, and the clinical applications of molecular cardiovascular imaging and the use of molecular techniques for local drug delivery are addressed

Exploring adaptive capacity to phosphorus challenges through two United Kingdom river catchments

Phosphorus (P) is a critical natural resource for food production, but one that is subject to global supply vulnerabilities. P is also responsible for endemic eutrophication in waterbodies due to poor stewardship in the food chain. Catchments are natural social-ecologically bounded systems for P use in agriculture and water management. Stakeholders, such as farmers, water and sewerage service companies, local authorities, and environmental organisations mediate catchment adaptive capacity to P supply risks and P pollution in waterbodies. Adaptive capacity at this level has been insufficiently explored in addressing the P challenge, yet is essential to it. We address this gap by exploring through a qualitative study of stakeholders in two United Kingdom catchments. Our results suggest that the awareness and relevance of P-supply challenges is low in catchments, but the problem of waterbody vulnerability to excess P is of greater concern. Our findings highlight the roles in adaptive capacity of entrenched practices; knowledge and training activities and organisations; stakeholder cooperation and synergy; funding, infrastructure, and technology; the governance environment; and time needed to draw down P. We find that farmers and water companies are especially important to adaptive capacity as they directly interact with P flows. We therefore suggest that catchment adaptive capacity would be significantly improved through a well-supported, and expanded package of existing efforts such as providing scientific evidence of catchment P dynamics; training; payments; more empowered local governance. This effort would support catchment stakeholders to adopt effective P-stewardship practices within a multi-decade integrated catchment management strategy

Exploring adaptive capacity to phosphorus challenges through two United Kingdom river catchments

Phosphorus (P) is a critical natural resource for food production, but one that is subject to global supply vulnerabilities. P is also responsible for endemic eutrophication in waterbodies due to poor stewardship in the food chain. Catchments are natural social-ecologically bounded systems for P use in agriculture and water management. Stakeholders, such as farmers, water and sewerage service companies, local authorities, and environmental organisations mediate catchment adaptive capacity to P supply risks and P pollution in waterbodies. Adaptive capacity at this level has been insufficiently explored in addressing the P challenge, yet is essential to it. We address this gap by exploring through a qualitative study of stakeholders in two United Kingdom catchments. Our results suggest that the awareness and relevance of P-supply challenges is low in catchments, but the problem of waterbody vulnerability to excess P is of greater concern. Our findings highlight the roles in adaptive capacity of entrenched practices; knowledge and training activities and organisations; stakeholder cooperation and synergy; funding, infrastructure, and technology; the governance environment; and time needed to draw down P. We find that farmers and water companies are especially important to adaptive capacity as they directly interact with P flows. We therefore suggest that catchment adaptive capacity would be significantly improved through a well-supported, and expanded package of existing efforts such as providing scientific evidence of catchment P dynamics; training; payments; more empowered local governance. This effort would support catchment stakeholders to adopt effective P-stewardship practices within a multi-decade integrated catchment management strategy