Studying neuroanatomy using MRI

The study of neuroanatomy using imaging enables key insights into how our brains function, are shaped by genes and environment, and change with development, aging, and disease. Developments in MRI acquisition, image processing, and data modelling have been key to these advances. However, MRI provides an indirect measurement of the biological signals we aim to investigate. Thus, artifacts and key questions of correct interpretation can confound the readouts provided by anatomical MRI. In this review we provide an overview of the methods for measuring macro- and mesoscopic structure and inferring microstructural properties; we also describe key artefacts and confounds that can lead to incorrect conclusions. Ultimately, we believe that, though methods need to improve and caution is required in its interpretation, structural MRI continues to have great promise in furthering our understanding of how the brain works

Relations between endomorphism rings, injectivity, surjectivity and uniserial modules

For a right module MR over a ring R, we consider the set I of all the endomorphisms \u3c6 E:= End(MR) that are not injective and the set K of all the endomorphisms \u3c6 that are not surjective. We prove that when MR is a uniserial module, then E/K is a left chain domain and E/I is a right chain domain. The technique we make use of to prove this can be applied to arbitrary modules MR, not-necessarily uniserial. When the endomorphisms \u3c6 are not in I (not in K), then left (right) divisibility in E corresponds to inclusion in the lattice (MR) of all submodules of MR. This allows to study factorizations of injective (surjective, respectively) endomorphisms of MR analyzing finite chains in the partially ordered set (MR)

A new tensor model for the measurement of diffusional anisotropy due to restricted diffusion

Diffusion Tensor Imaging (DTI, Basser et al 1994) is the most widely used technique to measure the diffusion properties of the human brain tissues in-vivo. Although datasets comprising 30 samples, all but one of which acquired at a single b-value, are enough to estimate the diffusion tensor, in recent yearsnumerous acquisition schemes featuring more general diffusion encodings have been proposed. In order to vary the b-value, it is necessary to change either the gradient strength (G) or the duration or separation of the diffusion pulses. In the case of unrestricted diffusion (e.g. Gaussian), the b-value is theonly parameter that determines the diffusion-weighting. Thus, the same level of diffusion sensitization, hence the same signal attenuation, can be obtained by varying the gradient strength or the effective diffusion time (tau). In more realistic cases of diffusion, e.g., within restricted media (such as cells)changing G and tau have different effects on the signal. In this work, we compared the effect of changing the tau and the gradient strength G on the reconstruction error, using two tensor models: DTI, which is appropriate only for unrestricted diffusion, and the Diffusion Imaging with Confinement Tensor(DICT, Yolcu et al., Afzali et al 2015), which is applicable to both restricted and unrestricted diffusion scenarios. singthe either model, it is possible to estimate clinically important features, such as the Mean Diffusivity, and the Fractional Anisotropy (Afzali et al 2015, Pierpaoli and Basser 1996)

The analysis of radial displacements occurring near the face of a circular opening in weak rock mass

The effect of opening size, rock properties and stress conditions on the radial displacements ahead and behind of the advancing face of a circular opening is one of the most important topics in civil and mining engineering. In this paper we develop a prediction system for radial displacements around the face of an opening by combining rock mass rating classification system, a three dimensional finite difference code and multiple regression modeling. Predictive equations and response surfaces for rock mass response are proposed. By using these equations and response surfaces, it is possible to assess radial displacements around the face and to construct the longitudinal deformation profile of a circular opening with different diameters excavated in weak rock mass under different stress conditions. The predictive equations were validated by means of statistical tests and analytical solution. Proposed response surfaces and equations can provide the basis of guiding the design and construction of underground openings. © 2010 Elsevier Ltd

Influence of CaO on the nanohardness behaviour of AZ63 magnesium alloys produced by mechanical alloying method

In this study we aimed to produce AZ63 magnesium alloys containing different amounts of CaO, to investigate the nanohardness behaviour of the resulting alloys. These alloys were produced by mechanical alloying under argon atmosphere. Magnesium based alloys with the initial CaO content of 0.1%, 0.3%, and 0.5% were produced by high-energy ball milling, followed by process that involved cold pressing and sintering. These alloys were characterized using scanning electron microscopy, scanning probe microscopy, X-ray diffraction, and nanoindentation methods. Unloading segments of nanoindentation curves were analyzed using Oliver-Pharr method. Experimental results show that measured nanohardness exhibits a peak load dependence. As a result, in these alloys the microstructure and nanohardness depend on the content of CaO

A Novel Tea factory waste metal-free catalyst as promising supercapacitor electrode for hydrogen production and energy storage: A dual functional material

In this study, the catalyst produced from tea factory waste (TFW) was used for the first time for hydrogen production by methanolysis of sodium borohydride (NaBH4). The produced material had a dual function as both catalyst and supercapacitor; therefore, it was named 'cap-cat'(capacitor-catalyst) by us. In this context, TFW was treated with acetic acid for 24 h at 80 degrees C. The sample was then subjected to combustion in the oven to synthesize the catalyst. Afterward, the most efficient TFW-CH3COOH catalyst was synthesized by evaluating different acid ratios, burning temperatures and times. The best conditions for the acetic acid ratio, burning temperature, and time were found out 3 M, 300 degrees C, and 60 min. The characterization of the catalyst was done using SEM-EDX, FTIR, XRD analysis. Hydrogen generation experiments from NaBH4 by methanolysis were performed at various catalyst concentrations in the range of 0.05-0.2 g, diverse NaBH4 ratio of 1 to 7.5%, and at different reaction temperatures (30-60 degrees C). The HGR of the synthesized catalyst was recorded as 3096.4, 8367.5, 11227.9, and 23,507 mLmin(-1)g(cat)(-1) for these temperatures (30, 40, 50, and 60 degrees C), respectively. Also the activation energy was calculated as 38.6 kJ mol(-1). Subsequently, the CV (cyclic voltammetry) and charge-discharge curves of the prototypes produced were substantially similar to the supercapacitor curves in the literature. Gravimetric capacitance was found to be 155F/g at a current density of 2 A/g