The interface between the polar LaAlO3 and nonpolar SrTiO3 layers has been shown to exhibit various electronic and magnetic phases such as two dimensional electron gas, superconductivity, magnetism and electronic phase separation. These rich phases are expected due to the strong interplay between charge, spin and orbital degree of freedom at the interface between these complex oxides, leading to the electronic reconstruction in this system. However, until now all of these new properties have been studied extensively based on the interfaces which involve a polar LaAlO3 layer. To investigate the role of the A and B cationic sites of the ABO3 polar layer, here we study various combinations of polar/nonpolar oxide (NdAlO3/SrTiO3, PrAlO3/SrTiO3 and NdGaO3/SrTiO3) interfaces which are similar in nature to LaAlO3/SrTiO3 interface. Our results show that all of these new interfaces can also produce 2DEG at their interfaces, supporting the idea that the electronic reconstruction is the driving mechanism for the creation of the 2DEG at these oxide interfaces. Furthermore, the electrical properties of these interfaces are shown to be strongly governed by the interface strain and strong correlation effects provided by the polar layers. Our observations may provide a novel approach to further tune the properties of the 2DEG at the selected polar/nonpolar oxide interfaces.

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We report evolution of the two-dimensional electron gas behavior at the NdAlO 3 /SrTiO 3 heterointerfaces with varying thicknesses of the NdAlO 3 overlayer. The samples with a thicker NdAlO 3 show strong localizations at low temperatures and the degree of localization is found to increase with the NdAlO 3 thickness. The T -1/3 temperature dependence of the sheet resistance at low temperatures and the magnetoresistance study reveal that the conduction is governed by a two-dimensional variable range hopping mechanism in this strong localized regime. We attribute this thickness dependence of the transport properties of the NdAlO 3 /SrTiO 3 interfaces to the interface strain induced by the overlayers. 2The discovery of the two dimensional electron gas (2DEG) at the LaAlO 3 /SrTiO 3 oxide hetero interface 1 has made this material system a primary candidate for applications in oxide electronics. This system has further triggered the interest of the community as novel phenomena, such as superconductivity and magnetism, 2-5 were observed at this interface and furthermore these properties were shown to be sensitive to the external parameters such as O 2 deposition pressure 6 and strain effects 7 at the interface. One of the characteristic features of the 2DEG is the overlayer thickness dependence 8,9 of its conductivity, where a thickness dependent metal to insulator transition (MIT) transition was observed at a critical thickness of LaAlO 3 overlayer.Furthermore, a weak to strong localization 10,11 and magnetic Kondo behavior 6 were reported in thicker samples, suggesting that a variety of conduction mechanisms were operating at these interfaces. Moreover the superconductivity at these interfaces was also shown to be sensitive to the thickness 2 of the over layer where the localization is suggested to be minimum. Very recently, we reported the formation of 2DEG at various polar/nonpolar oxide interfaces 12showing a stronger localization of 2DEG compared to that at the LaAlO 3 /SrTiO 3 interfaces. This stronger localization can possibly give rise to different transport properties, and thus its dependence on the overlayer thickness is very crucial to be investigated. LaAlO 3 /SrTiO 3 . 9 However, a significant observation can be made for the low temperature transport for the thicker NdAlO 3 /SrTiO 3 samples, i.e. below 15 K the variation in R s is more distinct indicating a different type of transport mechanism operating at low temperatures. Figure 2b shows the temperature dependenence of n s and  for the corresponding samples. For the thicker samples the n s decreases in the temperature range of 300-20 K, can be attributed to the localization of activated charge carriers at the interface. significantly towards the low temperatures, which is further evidence for strong localization in these samples. The low temperature behavior of R s , n s and  confirms the strong localization of carriers associated with a change of transport mechanism at low temperatures.In general, the observed low temperature sharp upturns in R ...

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This paper presents a system that is able to automatically identify, segment, and track the cross-section of the internal jugular vein (IJV) and the common carotid artery (CCA) in an ultrasound image feed during a central venous catheter (CVC) placement procedure. The goal is to provide assistance to the practitioner in order to decrease the probability of complications stemming from inadvertent punctures of the CCA during the procedure. In the system, a modified Star algorithm is implemented to segment and track the blood vessel throughout an ultrasound video feed. A novel algorithm based on a cascading classifier is used to identify the location of the IJV and the CCA for two main tasks: (1) selecting the initial seed point at the start of tracking and (2) validating the segmentation results at each subsequent frame. The classifier uses shape features (vessel area, ellipse fitting error, vessel depth, vessel eccentricity) and pixel-based features (pixel intensity and the histogram of oriented gradients descriptor) to differentiate between vessel and non-vessel structures and also differentiate between the IJV and the CCA. Evaluated on a database of 800 ultrasound images containing the cross-section of both vessels, the cascading classifier was able to identify the IJV and the CCA in 92.25% and 85.13% of the images respectively without any initialization from the user at a maximum processing rate of 40.65 frames per second. This allows identification to be conducted in real-time with existing ultrasound machines.