Spire stimulates nucleation by Cappuccino and binds both ends of actin filaments.

The actin nucleators Spire and Cappuccino synergize to promote actin assembly, but the mechanism of their synergy is controversial. Together these proteins promote the formation of actin meshes, which are conserved structures that regulate the establishment of oocyte polarity. Direct interaction between Spire and Cappuccino is required for oogenesis and for in vitro synergistic actin assembly. This synergy is proposed to be driven by elongation and the formation of a ternary complex at filament barbed ends, or by nucleation and interaction at filament pointed ends. To mimic the geometry of Spire and Cappuccino in vivo, we immobilized Spire on beads and added Cappuccino and actin. Barbed ends, protected by Cappuccino, grow away from the beads while pointed ends are retained, as expected for nucleation-driven synergy. We found that Spire is sufficient to bind barbed ends and retain pointed ends of actin filaments near beads and we identified Spire's barbed-end binding domain. Loss of barbed-end binding increases nucleation by Spire and synergy with Cappuccino in bulk pyrene assays and on beads. Importantly, genetic rescue by the loss-of-function mutant indicates that barbed-end binding is not necessary for oogenesis. Thus, increased nucleation is a critical element of synergy both in vitro and in vivo

From Farm to Fork: an Assessment of Collaborative Supply Relationships to Underpin Food Tourism

Internationally, the food sector appears to be thriving and has excellent growth prospects. In a tourism context food is considered as a major element of tourism strategy, it is accepted as a primary motivator in destination choice and related tourist desires for sense of the authentic. In Ireland, food production, distribution, marketing and food tourism are the combined remit of a number of policy bodies. In a competitive economic environment, policy makers advocate the cultivation of food culture through greater supply chain collaboration as a means to improving product quality, customer satisfaction and competitiveness. This paper presents the findings of an in-depth consultation process with a wide sample of stakeholder groups to propose a framework of tangible recommendations to enhance direct supply chain relationships in food tourism and food service operations. It is envisaged that this research will act as a reference point for policy makers to guide, support, facilitate and assist hospitality industry and food producers to collaborate and form sustainable strategic relationships to support food tourism

Dynamic Haloscope Scanning for Axion Dark Matter Searches

The axion is a well-motivated dark matter candidate, and numerous laboratory searches are currently underway to detect signatures of its interaction with the standard model. In this thesis, I show how recent advances in the data analysis enable a novel method of optimization: the scanning protocol. I begin by creating an open-source software package to simulate haloscope detector scanning. Using the flexibility provided by Bayesian statistical methods and testing on the simulation suite, I develop a dynamic scanning algorithm. A preliminary version of this algorithm enables a 10% speedup in generating axion exclusions with no cost to experimental overhead. This technique is also naturally compatible with machine learning techniques for optimization, and I have taken the preliminary steps to begin training a reinforcement learning model.</p

Impact of Mandatory Diversity Training: Lessons from a Private University

Attendance at diversity training programs is often dictated by management, and participants find themselves caught between their genuine desire to broaden their understanding of the subject and resentment at being forced to do so. The outcomes of these mandatory training programs have not been systematically assessed. This study looks at the cognitive, attitudinal, and behavioral impacts of attending such a program and finds valuable lessons learned and cautious room for optimism

Long-term controlled delivery of rhBMP-2 from collagen-hydroxyapatite scaffolds for superior bone tissue regeneration.

The clinical utilization of recombinant human bone morphogenetic protein 2 (rhBMP-2) delivery systems for bone regeneration has been associated with very severe side effects, which are due to the non-controlled and non-targeted delivery of the growth factor from its collagen sponge carrier post-implantation which necessitates supraphysiological doses. However, rhBMP-2 presents outstanding regenerative properties and thus there is an unmet need for a biocompatible, fully resorbable delivery system for the controlled, targeted release of this protein. With this in mind, the purpose of this work was to design and develop a delivery system to release low rhBMP-2 doses from a collagen-hydroxyapatite (CHA) scaffold which had previously been optimized for bone regeneration and recently demonstrated significant healing in vivo. In order to enhance the potential for clinical translation by minimizing the design complexity and thus upscaling and regulatory hurdles of the device, a microparticle and chemical functionalization-free approach was chosen to fulfill this aim. RhBMP-2 was combined with a CHA scaffold using a lyophilization fabrication process to produce a highly porous CHA scaffold supporting the controlled release of the protein over the course of 21days while maintaining in vitro bioactivity as demonstrated by enhanced alkaline phosphatase activity and calcium production by preosteoblasts cultured on the scaffold. When implanted in vivo, these materials demonstrated increased levels of healing of critical-sized rat calvarial defects 8weeks post-implantation compared to an empty defect and unloaded CHA scaffold, without eliciting bone anomalies or adjacent bone resorption. These results demonstrate that it is possible to achieve bone regeneration using 30 times less rhBMP-2 than INFUSE®, the current clinical gold standard; thus, this work represents the first step of the development of a rhBMP-2 eluting material with immense clinical potential

Protecting backaction-evading measurements from parametric instability

Noiseless measurement of a single quadrature in systems of parametrically coupled oscillators is theoretically possible by pumping at the sum and difference frequencies of the two oscillators, realizing a backaction-evading (BAE) scheme. Although this would hold true in the simplest scenario for a system with pure three-wave mixing, implementations of this scheme are hindered by unwanted higher-order parametric processes that destabilize the system and add noise. We show analytically that detuning the two pumps from the sum and difference frequencies can stabilize the system and fully recover the BAE performance, enabling operation at otherwise inaccessible cooperativities. We also show that the acceleration demonstrated in a weak signal detection experiment [PRX QUANTUM 4, 020302 (2023)] was only achievable because of this detuning technique.Comment: 7 pages, 3 figure

Hypoxia-mimicking bioactive glass/collagen glycosaminoglycan composite scaffolds to enhance angiogenesis and bone repair.

One of the biggest challenges in regenerative medicine is promoting sufficient vascularisation of tissue-engineered constructs. One approach to overcome this challenge is to target the cellular hypoxia inducible factor (HIF-1α) pathway, which responds to low oxygen concentration (hypoxia) and results in the activation of numerous pro-angiogenic genes including vascular endothelial growth factor (VEGF). Cobalt ions are known to mimic hypoxia by artificially stabilising the HIF-1α transcription factor. Here, resorbable bioactive glass particles (38 μm and 100 μm) with cobalt ions incorporated into the glass network were used to create bioactive glass/collagen-glycosaminoglycan scaffolds optimised for bone tissue engineering. Inclusion of the bioactive glass improved the compressive modulus of the resulting composite scaffolds while maintaining high degrees of porosity (\u3e97%). Moreover, in vitro analysis demonstrated that the incorporation of cobalt bioactive glass with a mean particle size of 100 μm significantly enhanced the production and expression of VEGF in endothelial cells, and cobalt bioactive glass/collagen-glycosaminoglycan scaffold conditioned media also promoted enhanced tubule formation. Furthermore, our results prove the ability of these scaffolds to support osteoblast cell proliferation and osteogenesis in all bioactive glass/collagen-glycosaminoglycan scaffolds irrespective of the particle size. In summary, we have developed a hypoxia-mimicking tissue-engineered scaffold with pro-angiogenic and pro-osteogenic capabilities that may encourage bone tissue regeneration and overcome the problem of inadequate vascularisation of grafts commonly seen in the field of tissue engineering

Association of excessive precipitation and agricultural land use with honey bee colony performance

Context From landscape variables to weather, multiple environmental factors affect honey bees and other pollinators. Detailed honey bee colony assessments in a variety of landscape and weather conditions offer the opportunity to develop a mechanistic understanding of how landscape composition, configuration, and weather are associated with colony nutrition, demography, and productivity. Objectives Our objective was to test if weather and landscape characteristics (e.g., agricultural versus forested land use) are associated with different honey bee colony outcomes (foraged nectar mass, foraged pollen mass, pupal population size, and adult population size change). Methods We collected detailed colony measurements on over 450 honey bee colonies over four years across an agricultural-to-forested land use gradient in Michigan, USA. Results We found that higher than normal precipitation in the preceding spring and fall was negatively correlated with colony size change and with foraged nectar mass, respectively. Sites surrounded by less agricultural land and more forested land also had fewer pupae by the end of summer. Conclusions These inter-dependent colony metrics offer insights into environmental-plant-pollinator dynamics. Our finding that extreme weather events, associated with climate change, are negatively correlated with colony performance point to likely lagged effects of weather on pollinator floral resources. Landscapes managed with climate-resilient, temporally continuous floral resources are likely to support pollinators. Capturing extreme weather phenomena in field studies is a valuable way to investigate the associations between land use, climate change and biological systems. However, caution should be taken in overinterpreting observational studies, so further research is needed