Classification of CT brain images based on deep learning networks

While Computerised Tomography (CT) may have been the first imag-ing tool to study human brain, it has not yet been implemented into clinical decision making process for diagnosis of Alzheimers disease (AD). On the other hand, with the nature of being prevalent, inexpensive and non-invasive, CT does present diagnostic features of AD to a great ex-tent. This study explores the significance and impact on the application of the burgeoning deep learning techniques to the task of classification of CT brain images, in particular utilising convolutional neural network (CNN), aiming at providing supplementary information for the early di-agnosis of Alzheimers disease. Towards this end, three categories of CT images (N=285) are clustered into three groups, which are AD, Lesion (e.g. tumour) and Normal ageing. In addition, considering the character-istics of this collection with larger thickness along the direction of depth (z) (∼3-5mm), an advanced CNN architecture is established integrating both 2D and 3D CNN networks. The fusion of the two CNN networks is subsequently coordinated based on the average of Softmax scores obtained from both networks consolidating 2D images along spatial axial directions and 3D segmented blocks respectively. As a result, the classification ac-curacy rates rendered by this elaborated CNN architecture are 85.2%, 80% and 95.3% for classes of AD, Lesion and Normal respectively with an average of 87.6%. Additionally, this improved CNN network appears to outperform the others when in comparison with 2D version only of CNN network as well as a number of state of the art hand-crafted approaches. As a result, these approaches deliver accuracy rates in percentage of 86.3, 85.6+-1:10, 86.3+-1:04, 85.2+-1:60, 83.1+-0:35 for 2D CNN, 2D SIFT, 2DKAZE, 3D SIFT and 3D KAZE respectively. The two major contributions of the paper constitute a new 3-D approach while applying deep learning technique to extract signature information rooted in both 2D slices and 3D blocks of CT images and an elaborated hand-crated approach of 3D KAZE

A new approach to estimation of non-isotropic scale factors for correction of MR distortion.

Purpose: When performing image-guided neurosurgery, MR images are widely applied for the planning of surgical path. However, a MR image sometimes suffers geometry distortion, limiting the surgical outcome. Correction of geometry distortions are thus performed prior to the surgical operation, which is normally in the reference of CT images. Usually distortions can be system inherent, e.g., field inhomogeneity, or patient induced, such as wearing implantable devices, and are detected using the fiducial markers from a head frame. By registration of the markers located from both MR and CT images, it is expected the distorted or transformed parameters from MR images can be found. As such, most existing approaches apply the work developed by Arun et al to locate translate and rotate matrixes using least-squares technique, which however does not take scale transformation into account and has since been extended to include an isotropic scaling. In our study, it is found that the scale factors are not the same along 3 axial directions of a MR image, i.e, with nonisotropic scale, necessitating the need to find scale matrix as well as the other transformation matrixes

Formation of Enhanced Uniform Chiral Fields in Symmetric Dimer Nanostructures

Chiral fields with large optical chirality are very important in chiral molecules analysis, sensing and other measurements. Plasmonic nanostructures have been proposed to realize such super chiral fields for enhancing weak chiral signals. However, most of them cannot provide uniform chiral near-fields close to the structures, which makes these nanostructures not so efficient for applications. Plasmonic helical nanostructures and blocked squares have been proved to provide uniform chiral near-fields, but structure fabrication is a challenge. In this paper, we show that very simple plasmonic dimer structures can provide uniform chiral fields in the gaps with large enhancement of both near electric fields and chiral fields under linearly polarized light illumination with polarization off the dimer axis at dipole resonance. An analytical dipole model is utilized to explain this behavior theoretically. 30 times of volume averaged chiral field enhancement is gotten in the whole gap. Chiral fields with opposite handedness can be obtained simply by changing the polarization to the other side of the dimer axis. It is especially useful in Raman optical activity measurement and chiral sensing of small quantity of chiral molecule

Partially linear censored quantile regression

Censored regression quantile (CRQ) methods provide a powerful and flexible approach to the analysis of censored survival data when standard linear models are felt to be appropriate. In many cases however, greater flexibility is desired to go beyond the usual multiple regression paradigm. One area of common interest is that of partially linear models: one (or more) of the explanatory covariates are assumed to act on the response through a non-linear function. Here the CRQ approach of Portnoy (J Am Stat Assoc 98:1001–1012, 2003) is extended to this partially linear setting. Basic consistency results are presented. A simulation experiment and unemployment example justify the value of the partially linear approach over methods based on the Cox proportional hazards model and on methods not permitting nonlinearity

Trends and driving forces of China's virtual land consumption and trade

Land resources are important for China’s rapid economic development, especially for food and construction. China’s land resources are under tremendous pressures, and therefore land use is increasingly displaced to other parts of the world. This study analyses the evolution and driving forces of China’s land consumption from 1995 to 2015. The main results show that China’s land footprint increased from 8.8% of the global land resources under human use in 1995 to 15.7% in 2015. China’s domestic land resources are mainly used for serving domestic consumption. Moreover, China needs to import virtual land from foreign countries to satisfy 30.8% of its land demand. Among the three land use types of cropland, grassland and forests, grassland had the largest fraction in China’s land footprint from 1995 to 2000, while forest has become the largest one since 2000. China’s virtual land trade experienced a sharp increase in net imports from 9.4E + 04 km2 in 1995 to 3.4E + 06 km2 in 2015. Observing China’s virtual land network by a cluster analysis, this study concludes that China keeps tight relationships with Australia, Japan, Brazil and Korea for its cropland consumption, and Canada, USA, Mexico, Australia, Korea and Japan are relevant for its grassland consumption. In addition, decomposition analysis results show that affluence is the major driving factor for China’s land consumption, while changes in land use intensity could mitigate some of the related effects. Lastly, policy recommendations are proposed so that China can move toward sustainable land management

Understanding the effect of elastic wheels on an urban railway system using a new wheel–rail coupling vibration model

In order to control the wheel–rail coupling vibration of an urban railway system, a combined elastic wheel damping structure is proposed where the key parameters that determine the structural damping and thereby control the vibration of the railway system are explored. The vertical acceleration of the elastic wheels is obtained for a range of stiffness coefficients as the wheel moves on an irregular track, which is calculated by the (Formula presented.) method in the time domain. The results show that the vertical acceleration changes with a V-shaped trend, with an increase of wheel stiffness coefficient, which allows the optimum stiffness coefficient for minimum vertical acceleration of the elastic wheel to be obtained. It is observed that when attempting to suppress wheel vibration, an elastic wheel with a larger stiffness coefficient is needed as the degree of track irregularity reduces. This paper provides new insights into the effect of wheel elasticity on vibration characteristics, and thereby provides directions to improve ride quality and passenger comfort.</p

Local trace formulae and scaling asymptotics in Toeplitz quantization, II

In the spectral theory of positive elliptic operators, an important role is played by certain smoothing kernels, related to the Fourier transform of the trace of a wave operator, which may be heuristically interpreted as smoothed spectral projectors asymptotically drifting to the right of the spectrum. In the setting of Toeplitz quantization, we consider analogues of these, where the wave operator is replaced by the Hardy space compression of a linearized Hamiltonian flow, possibly composed with a family of zeroth order Toeplitz operators. We study the local asymptotics of these smoothing kernels, and specifically how they concentrate on the fixed loci of the linearized dynamics.Comment: Typos corrected. Slight expository change

Raman Spectroscopy Study of alpha-, beta-, gamma-NaxCoO2 and gamma-(Ca,Sr)xCoO2

Raman spectroscopy measurements have been performed on alpha-, beta-, gamma-NaxCoO2 phases differing in their stacking of CoO6 octahedra along the c-axis direction. The results demonstrate that, in general, there are five active phonons for gamma-Na0.75CoO2, two Raman active phonons for alpha-NaCoO2, and four Raman active phonons for beta-NaCoO2. We have also performed Raman scattering measurements on several gamma-(Ca,Sr)xCoO2 (0.15 <= x <= 0.35) samples which show well-defined intercalated Ca/Sr-ordering. The experimental data show that the intercalated cation ordering could result in visible alterations on Raman spectral structures. The observations of the spectral changes along with the variation of the CoO6 stacking, as well as the intercalated Sr/Ca ordering suggest that the interlayer interaction plays an important role for understanding the lattice dynamics in this layered system.Comment: 23 pages, 5 figures, Physical Review B, in pres