Magnetic fields generated by human and animal organs, such as the heart, brain and nervous system carry information useful for biological and medical purposes. These magnetic fields are most commonly detected using cryogenically-cooled superconducting magnetometers. Here we present the first detection of action potentials from an animal nerve using an optical atomic magnetometer. Using an optimal design we are able to achieve the sensitivity dominated by the quantum shot noise of light and quantum projection noise of atomic spins. Such sensitivity allows us to measure the nerve impulse with a miniature room-temperature sensor which is a critical advantage for biomedical applications. Positioning the sensor at a distance of a few millimeters from the nerve, corresponding to the distance between the skin and nerves in biological studies, we detect the magnetic field generated by an action potential of a frog sciatic nerve. From the magnetic field measurements we determine the activity of the nerve and the temporal shape of the nerve impulse. This work opens new ways towards implementing optical magnetometers as practical devices for medical diagnostics.The magnetic field generated around a signaling nerve fiber is of key interest both from a basic scientific and a clinical point of view. The transmembrane potentials have been extensively measured with electrophysiological techniques. Magnetic field measurements are insensitive to the transmembrane currents as the fields from the opposite currents in and out of the membrane cancel. Instead, magnetic field measurements allow for a true measurement of the axon's axial net current, which is the depolarizing wavefront driving the action potential. Magnetic field recordings also allow for non-invasive measurements of the conduction velocity of peripheral nerves 1 which is necessary for diagnostics of multiple sclerosis, myotonia and intoxication in patients.The magnetic field of a nerve impulse was first measured by Wikswo et al. 2 using a combination of a superconducting SQUID magnetometer and a toroidal pick-up coil through which the nerve had to be pulled. This method is not compatible with in vivo diagnostics and yields the magnetic field values which are much higher than that in an animal because the return currents in the surrounding tissue are not measured. Here we are able to detect the nerve impulse with the sensor placed beside the nerve, several millimeters away, the setting compatible with in vivo studies. Detection of nerve impulses with a magnetometer based on Nitrogen-Vacancy centers in diamond has recently been reported 3 . Such magnetometers seem promising for magnetic field microscopy applications where the magnetometer can be placed at micrometer distance or closer to the biological object.Sensitivity of atomic magnetometers 4 improves with the number of atoms sensing the field, which for vapor magnetometers is defined by volume and temperature. For example, femtoTesla sensitivity has been achieved with magnetometers operating at a temperature of seve...

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With the economic restructuring during the 1980s and 1990s in Hong Kong, most manufacturing plants were relocated to China and many industrial buildings were left neglected or vacant. At the same time, owing to limited land supply, a shortage of affordable housing has been a problem in Hong Kong for many years. Adaptive reuse of industrial buildings may be a way of solving this problem. However, adaptive reuse is not an easy decision because there are many factors affecting adaptive reuse. Therefore, this paper examines the current situation of adaptive reuse of industrial buildings in Hong Kong and identifies a list of factors affecting the adaptive reuse of industrial buildings. Six factors are considered Critical Success Factors (CSFs). Based on a Principal Component Analysis, 33 factors are grouped into eight principal components, namely, sustainability, economics and finance, the market, changeability, location and neighborhood, culture and public interests, legal and regulatory matters, and the physical condition of the building. The identified CSFs and principal factors provide a useful reference for various stakeholders to have a clear understanding of the adaptive reuse of industrial buildings in Hong Kong, especially for the government to review current policies of adaptive reuse.

Poly(3-hexylthiophene) (P3HT) monolayer has been investigated by scanning tunneling microscopy (STM). The monolayer was dominated by three kinds of ordered structure (I, II, and III), where the thiophene main chains lied parallel to one another, but high resolution STM images revealed that the arrangement of the hexyl side chains was different. In structure I, the hexyl side chains tilted at ~60° with respect to the main chain, and the interchain distance (distance between two parallel neighboring backbones) was ~1.41 nm. In structure II, the interchain distance was significantly larger at ~1.52 nm, and the hexyl side chains were liquid-like. Structure III exhibited similar interchain distance as structure II, but the hexyl side chains were perpendicular to the main chain and were interdigitated. In addition to these ordered domains, individual poly(3-hexylthiophene) chains in various special configurations were observed, and their unfolding into more stable structures was tracked by dynamic STM, which provides evidence that P3HT is a relatively flexible polymer.