The Effect of Calcium Ions on Mechanosensation and Neuronal Activity in Proprioceptive Neurons

Proprioception of all animals is important in being able to have coordinated locomotion. Stretch activated ion channels (SACs) transduce the mechanical force into electrical signals in the proprioceptive sensory endings. The types of SACs vary among sensory neurons in animals as defined by pharmacological, physiological and molecular identification. The chordotonal organs within insects and crustaceans offer a unique ability to investigate proprioceptive function. The effects of the extracellular environment on neuronal activity, as well as the function of associated SACs are easily accessible and viable in minimal saline for ease in experimentation. The effect of extracellular [Ca2+] on membrane properties which affect voltage-sensitivity of ion channels, threshold of action potentials and SACs can be readily addressed in the chordotonal organ in crab limbs. It is of interest to understand how low extracellular [Ca2+] enhances neural activity considering the SACs in the sensory endings could possibly be Ca2+ channels and that all neural activity is blocked with Mn2+. It is suggested that axonal excitability might be affected independent from the SAC activity due to potential presence of calcium activated potassium channels (K(Ca)) and the ability of Ca2+ to block voltage gated Na+ channels in the axons. Separating the role of Ca2+ on the function of the SACs and the excitability of the axons in the nerves associated with chordotonal organs is addressed. These experiments may aid in understanding the mechanisms of neuronal hyperexcitability during hypocalcemia within mammals

The Effect of Calcium Ions on Mechanosensation and Neuronal Activity in Proprioceptive Neurons

Proprioception of all animals is important in being able to have coordinated locomotion. Stretch activated ion channels (SACs) transduce the mechanical force into electrical signals in the proprioceptive sensory endings. The types of SACs vary among sensory neurons in animals as defined by pharmacological, physiological and molecular identification. The chordotonal organs within insects and crustaceans offer a unique ability to investigate proprioceptive function. The effects of the extracellular environment on neuronal activity, as well as the function of associated SACs are easily accessible and viable in minimal saline for ease in experimentation. The effect of extracellular [Ca2+] on membrane properties which affect voltage-sensitivity of ion channels, threshold of action potentials and SACs can be readily addressed in the chordotonal organ in crab limbs. It is of interest to understand how low extracellular [Ca2+] enhances neural activity considering the SACs in the sensory endings could possibly be Ca2+ channels and that all neural activity is blocked with Mn2+. It is suggested that axonal excitability might be affected independent from the SAC activity due to potential presence of calcium activated potassium channels (K(Ca)) and the ability of Ca2+ to block voltage gated Na+ channels in the axons. Separating the role of Ca2+ on the function of the SACs and the excitability of the axons in the nerves associated with chordotonal organs is addressed. These experiments may aid in understanding the mechanisms of neuronal hyperexcitability during hypocalcemia within mammals

Structural Equation Modeling to Analyze the Critical Driving Factors and Paths for Off-site Construction in China

© 2017 Korean Society of Civil Engineers and Springer-Verlag GmbH Germany, part of Springer Nature Off-site Construction (OSC) is an alternative to conventional construction. However, China lags behind developed countries in terms of its OSC development. The chief goal of this study is to demonstrate the critical driving forces and solutions that promote OSC development. A total of 21 hypotheses are established to present the interrelations among eight driving forces. Based on 176 valid responses from developers in mainland China, a structural equation model is built to explore the key solutions and the critical driving forces. Most driving forces, such as Pursuit of Sustainable Competitiveness (PSC), Governmental Policies and Regulations (GPR), Technological Innovation (TI), Corporate Social Responsibility (CSR), and Construction Market Demand (CMD), can affect a Corporation’s Willingness and Behavior (CWB) in adopting OSC through two mediating factors, namely, Economic Benefits (EB) and social and environmental benefits. The findings highlight five main driving solutions to promote OSC, namely, “PSC ? EB ? CWB,” “PSC ? TI ? EB ? CWB,” “GPR ? TI ? EB ? CWB,” “GPR ? CSR ? CWB,” and “GPR ? CMD ? CWB.” Governments and project clients are also identified as important players in the development of OSC in China. These results provide a valuable reference for the government to understand the underlying interrelationships among the driving forces and key solutions to the development of OSC in China

Innovation in small, project-based construction firms

Relevant literature is synthesized to provide a holistic picture of our current knowledge of innovation in small, project-based firms, highlighting significant gaps in the broad areas of ‘focus and outcome’, ‘organizational capabilities’, ‘context’ and ‘process’. Research findings from fieldwork focused on the construction industry are offered to address these gaps. In particular, a consensus model is given of the organizational factors dynamically at play. It is shown that typically the innovations of small, projectbased firms are closely tied to their operational activities and are pushed forward by owners who utilize very scarce resources to make progress in the interstices of normal business. This leads to an emphasis on taking up established technologies through ‘learning on the job’. Growth per se is not an important target. The motivation to act is generally to get past a survival mode of operating and to achieve stability by satisfying clients. These characteristics contrast with large organizations, especially in terms of the role of the owner, the close focus on niche markets and the lack of slack resources to innovate in parallel with normal business. It is hoped that these results will be of interest to other sectors where small, project-based firms operate