Modeling of composite beams and plates for static and dynamic analysis

A rigorous theory and corresponding computational algorithms was developed for a variety of problems regarding the analysis of composite beams and plates. The modeling approach is intended to be applicable to both static and dynamic analysis of generally anisotropic, nonhomogeneous beams and plates. Development of a theory for analysis of the local deformation of plates was the major focus. Some work was performed on global deformation of beams. Because of the strong parallel between beams and plates, the two were treated together as thin bodies, especially in cases where it will clarify the meaning of certain terminology and the motivation behind certain mathematical operations

Liver Sinusoid on a Chip: Long-Term Layered Co-Culture of Primary Rat Hepatocytes and Endothelial Cells in Microfluidic Platforms

We describe the generation of microfluidic platforms for the co-culture of primary hepatocytes and endothelial cells; these platforms mimic the architecture of a liver sinusoid. This paper describes a progressional study of creating such a liver sinusoid on a chip system. Primary rat hepatocytes (PRHs) were co-cultured with primary or established endothelial cells in layers in single and dual microchannel configurations with or without continuous perfusion. Cell viability and maintenance of hepatocyte functions were monitored and compared for diverse experimental conditions. When primary rat hepatocytes were co-cultured with immortalized bovine aortic endothelial cells (BAECs) in a dual microchannel with continuous perfusion, hepatocytes maintained their normal morphology and continued to produce urea for at least 30 days. In order to demonstrate the utility of our microfluidic liver sinusoid platform, we also performed an analysis of viral replication for the hepatotropic hepatitis B virus (HBV). HBV replication, as measured by the presence of cell-secreted HBV DNA, was successfully detected. We believe that our liver model closely mimics the in vivo liver sinusoid and supports long-term primary liver cell culture. This liver model could be extended to diverse liver biology studies and liver-related disease research such as drug induced liver toxicology, cancer research, and analysis of pathological effects and replication strategies of various hepatotropic infectious agents

NBSymple, a double parallel, symplectic N-body code running on Graphic Processing Units

We present and discuss the characteristics and performances, both in term of computational speed and precision, of a numerical code which numerically integrates the equation of motions of N 'particles' interacting via Newtonian gravitation and move in an external galactic smooth field. The force evaluation on every particle is done by mean of direct summation of the contribution of all the other system's particle, avoiding truncation error. The time integration is done with second-order and sixth-order symplectic schemes. The code, NBSymple, has been parallelized twice, by mean of the Computer Unified Device Architecture to make the all-pair force evaluation as fast as possible on high-performance Graphic Processing Units NVIDIA TESLA C 1060, while the O(N) computations are distributed on various CPUs by mean of OpenMP Application Program. The code works both in single precision floating point arithmetics or in double precision. The use of single precision allows the use at best of the GPU performances but, of course, limits the precision of simulation in some critical situations. We find a good compromise in using a software reconstruction of double precision for those variables that are most critical for the overall precision of the code. The code is available on the web site astrowww.phys.uniroma1.it/dolcetta/nbsymple.htmlComment: Paper composed by 29 pages, including 9 figures. Submitted to New Astronomy

Noninvasive in vivo imaging of diabetes-induced renal oxidative stress and response to therapy using hyperpolarized 13C dehydroascorbate magnetic resonance.

Oxidative stress has been proposed to be a unifying cause for diabetic nephropathy and a target for novel therapies. Here we apply a new endogenous reduction-oxidation (redox) sensor, hyperpolarized (HP) (13)C dehydroascorbate (DHA), in conjunction with MRI to noninvasively interrogate the renal redox capacity in a mouse diabetes model. The diabetic mice demonstrate an early decrease in renal redox capacity, as shown by the lower in vivo HP (13)C DHA reduction to the antioxidant vitamin C (VitC), prior to histological evidence of nephropathy. This correlates with lower tissue reduced glutathione (GSH) concentration and higher NADPH oxidase 4 (Nox4) expression, consistent with increased superoxide generation and oxidative stress. ACE inhibition restores the HP (13)C DHA reduction to VitC with concomitant normalization of GSH concentration and Nox4 expression in diabetic mice. HP (13)C DHA enables rapid in vivo assessment of altered redox capacity in diabetic renal injury and after successful treatment

Joint Blind Motion Deblurring and Depth Estimation of Light Field

Removing camera motion blur from a single light field is a challenging task since it is highly ill-posed inverse problem. The problem becomes even worse when blur kernel varies spatially due to scene depth variation and high-order camera motion. In this paper, we propose a novel algorithm to estimate all blur model variables jointly, including latent sub-aperture image, camera motion, and scene depth from the blurred 4D light field. Exploiting multi-view nature of a light field relieves the inverse property of the optimization by utilizing strong depth cues and multi-view blur observation. The proposed joint estimation achieves high quality light field deblurring and depth estimation simultaneously under arbitrary 6-DOF camera motion and unconstrained scene depth. Intensive experiment on real and synthetic blurred light field confirms that the proposed algorithm outperforms the state-of-the-art light field deblurring and depth estimation methods

Deep Depth From Focus

Depth from focus (DFF) is one of the classical ill-posed inverse problems in computer vision. Most approaches recover the depth at each pixel based on the focal setting which exhibits maximal sharpness. Yet, it is not obvious how to reliably estimate the sharpness level, particularly in low-textured areas. In this paper, we propose `Deep Depth From Focus (DDFF)' as the first end-to-end learning approach to this problem. One of the main challenges we face is the hunger for data of deep neural networks. In order to obtain a significant amount of focal stacks with corresponding groundtruth depth, we propose to leverage a light-field camera with a co-calibrated RGB-D sensor. This allows us to digitally create focal stacks of varying sizes. Compared to existing benchmarks our dataset is 25 times larger, enabling the use of machine learning for this inverse problem. We compare our results with state-of-the-art DFF methods and we also analyze the effect of several key deep architectural components. These experiments show that our proposed method `DDFFNet' achieves state-of-the-art performance in all scenes, reducing depth error by more than 75% compared to the classical DFF methods.Comment: accepted to Asian Conference on Computer Vision (ACCV) 201

Hyperpolarized 13C Spectroscopic Evaluation of Oxidative Stress in a Rodent Model of Steatohepatitis.

Nonalcoholic fatty liver disease (NAFLD) has become highly prevalent, now considered the most common liver disease in the western world. Approximately one-third of patients with NASH develop non-alchoholic steatohepatitis (NASH), histologically defined by lobular and portal inflammation, and accompanied by marked oxidative stress. Patients with NASH are at increased risk for cirrhosis and hepatocellular carcinoma, and diagnosis currently requires invasive biopsy. In animal models of NASH, particularly the methionine-choline deficient (MCD) model, profound changes are seen in redox enzymes and key intracellular antioxidants. To study antioxidant status in NASH non-invasively, we applied the redox probe hyperpolarized [1-13C] dehydroascorbic acid (HP DHA), which is reduced to Vitamin C (VitC) rapidly in the normal liver. In MCD mice, we observed a significant decrease in HP DHA to VitC conversion that accompanied hepatic fat deposition. When these animals were subsequently placed on a normal diet, resonance ratios reverted to those seen in control mice. These findings suggest that HP DHA, a potentially clinically translatable imaging agent, holds special promise in imaging NASH and other metabolic syndromes, to monitor disease progression and response to targeted therapies

Relationship of Wyoming Big Sagebrush Cover to Herbaceous Vegetation

We measured 328 sites in northern, central, and southern Montana and northern Wyoming during 2003 to test the relationship of herbaceous cover to Wyoming big sagebrush (Artemisia tridentata wyomingensis) cover. Long term annual precipitation at all sites was approximately 31 cm. Sagebrush and total herbaceous cover varied from 5 to 45 percent and 3.5 to 55 percent, respectively. Simple linear regression was the best fit model for predicting herbaceous cover from sagebrush cover using the highest Ra2 values as the model selection criteria. In northern Montana, herbaceous vegetation was predicted by sagebrush cover with the following model: Y = 37.4 – 0.61X (Ra2 = 0.16, P \u3c 0.001, n = 87). In central Montana, the model was Y = 14.0 – 0.00X (Ra2 = 0.00, P = 1.0, n = 155). In southern Montana, the model was Y = 35.9 – 0.39X (Ra2 = 0.14, P \u3c 0.001, n = 86). When all sites were combined, the best fit model was Y = 23.7 – 0.15X (Ra2 = 0.01, P \u3c 0.061, n = 328). This analysis determined that only 1 percent of the variation in herbaceous vegetation cover was associated with Wyoming big sagebrush cover. Management suggestions to reduce Wyoming big sagebrush in order to increase herbaceous production for greater sage-grouse (Centrocercus urophasianus) or livestock do not appear to be biologically sound. Keywords: Artemisia tridentata wyomingensis, line intercept, grass cover, Centrocercus urophasianus, forb cover, greater sage-grouse, sage-grouse habitat

Fine Scale Nest Site Selection of Greater Sage-Grouse In The Centennial Valley, Montana

The purpose of this study was to determine fine scale nest site selection of greater sage-grouse (Centrocercus urophasianus) in the Centennial Valley, MT. A total of ninety nests were found during 2014-2015 using radio-collared sage-grouse. Vegetation surveys were conducted at nests and random sites that measured the nest shrub and the cover available within 3m of the nest. Length of the branch over the nest (Lgth.LB), average axis width of the nest shrub (AvgAxis), lateral cover of the nest shrub (LCShrub), aerial cover of the nest shrub (ACShrub), and height of the lower branch over the nest (Ht.LB) were the habitat variables that received the most support. All habitat variables that were included in the top model were nest shrub morphological characteristics and cover provided by the nest shrub. Therefore, there is strong support that sage-grouse in the Centennial Valley are selecting nest sites based on the morphology of the nest shrub and the cover provided by that nest shrub. None of the habitat variables associated with herbaceous cover received much support for inclusion in our models. On average, residual cover (i.e. grass from previous year) provided concealment for only 4% of the nest bowl. The relative probability of a shrub being selected for a nest site is maximized when Lgth.LB >75cm long, AvgAxis >130cm wide, LCShrub >80%, and ACShrub > 70%. Managers should focus on conserving mountain big sagebrush (Artemisia tridentata ssp. vaseyana) and three-tip sagebrush (Artemisia tripartita) habitats because they were more likely to meet those shrub characteristics