Restoration of Atmospheric Turbulence Degraded Video using Kurtosis Minimization and Motion Compensation

In this thesis work, the background of atmospheric turbulence degradation in imaging was reviewed and two aspects are highlighted: blurring and geometric distortion. The turbulence burring parameter is determined by the atmospheric turbulence condition that is often unknown; therefore, a blur identification technique was developed that is based on a higher order statistics (HOS). It was observed that the kurtosis generally increases as an image becomes blurred (smoothed). Such an observation was interpreted in the frequency domain in terms of phase correlation. Kurtosis minimization based blur identification is built upon this observation. It was shown that kurtosis minimization is effective in identifying the blurring parameter directly from the degraded image. Kurtosis minimization is a general method for blur identification. It has been tested on a variety of blurs such as Gaussian blur, out of focus blur as well as motion blur. To compensate for the geometric distortion, earlier work on the turbulent motion compensation was extended to deal with situations in which there is camera/object motion. Trajectory smoothing is used to suppress the turbulent motion while preserving the real motion. Though the scintillation effect of atmospheric turbulence is not considered separately, it can be handled the same way as multiple frame denoising while motion trajectories are built.Ph.D.Committee Chair: Mersereau, Russell; Committee Co-Chair: Smith, Mark; Committee Member: Lanterman, Aaron; Committee Member: Wang, May; Committee Member: Tannenbaum, Allen; Committee Member: Williams, Dougla

A structural multi-mechanism constitutive equation for cerebral arterial tissue

AbstractA structural multi-mechanism constitutive equation is developed to describe the nonlinear, anisotropic, inelastic mechanical behavior of cerebral arterial tissue. Elastin and collagen fibers are treated as separate components (mechanisms) of the artery. Elastin is responsible for load bearing at low strain levels while the collagen mechanism is recruited for load bearing at higher strain levels. This work builds on an earlier model in which both the elastin and collagen mechanisms are represented by isotropic response functions [Wulandana, R., Robertson, A.M., 2005. An inelastic multi-mechanism constitutive equation for cerebral arterial tissue. Biomech. Model. Mechan. 4 (4), 235–248]. Here, the anisotropic material response of the wall is introduced through the collagen mechanism which is composed of helically distributed families of fibers. The orientation of these families is described using either a finite number of fiber orientations or a fiber distribution function. The fiber orientation or dispersion function can be prescribed directly from arterial histology data, or, taking a phenomenological approach, based on data fitting from bi-axial measurements. The activation of the collagen mechanism is specified using a new fiber strain based activation criterion. The multi-mechanism constitutive equation is applied to the simple case of cylindrical inflation and material constants are determined based on available inelastic experimental data for cerebral arteries. While the proposed model captures all features of this inelastic data, there is a pressing need for further experiments to refine the model

Salicylic acid collaborates with gene silencing to tomato defense against tomato yellow leaf curl virus (TYLCV)

Antiviral research in plants has been focused on RNA silencing (i.e. RNA interference), and several studies suggest that salicylic acid (SA)-mediated resistance is a key part of plant antiviral defense. However, the antiviral defense mechanism of SA-mediation is still unclear, and several recent studies have suggested a connection between SA-mediated defense and RNA silencing, which needs further characterization in TYLCV infection. In this study, both SA-mediated defense and the RNA silencing mechanism were observed to play an important role in the antiviral response against TYLCV. First, we found that SA application enhanced the resistance to TYLCV in tomato plants. The expression of RNA-silencing-related genes, such as SlDCL1, SlDCL2, SlDCL4, SlRDR2, SlRDR3a, SlRDR6a, SlAGO1, and SlAGO4, were significantly triggered by exogenous SA application and inoculation with TYLCV, respectively. Furthermore, silencing of SlDCL2, SlDCL4 in tomato resulted in attenuated resistance to TYLCV, and reduced the expression of defense-related genes (SlPR1 and SlPR1b) in SA-mediated defense after infection with TYLCV, particularly in SlDCL2/SlDCL4-silenced plants. Taken together, we conclude that SA collaborates with gene silencing in tomato defense against TYLCV

Structural multi-mechanism model with anisotropic damage for cerebral arterial tissues and its finite element modeling

A structural multi-mechanism constitutive equation is proposed to describe the anisotropic and damage behavior of cerebral arterial tissue. The arterial tissue is modeled as a non-linear, incompressible and inelastic material. In this model, new deformation criteria are proposed for the recruitment of collagen fibers and degradation of internal elastic lamina (IEL), two important features of early stage aneurysm formation. This structural anisotropic model is formulated by modifying a previous multi-mechanism model to include the fibrous nature of collagen fibers and incorporates morphological information such as fiber orientation and dispersion. An anisotropic damage model is included to characterize tissue weakening and softening before failure of the IEL, ground matrix or collagen fibers. Two possible damage mechanisms are formulated in this model: mechanical damage dependent on material strains and enzymatic damage induced by hemodynamic stresses. The elastin/ground matrix and collagen fibers are treated as separate components of arteries. The elastin and ground matrix, which are represented by an isotropic response, bear loads at low strain level, and degrade gradually due to damage or disrupt due to eventual failure. The collagen fibers are recruited into load-bearing and subfailure damage at higher strain levels. Two approaches are considered for modeling their anisotropic behavior. In the first, they are characterized by the anisotropic behavior of N fibers. In the second, the collagen fibers are arranged in two helically oriented families with dispersion in their orientation. The fiber distribution is modeled by an orientation density function or distribution parameter. The fiber orientation and dispersion can be prescribed from arterial histology studies, or identified from stress-strain response as structural parameters. Pressure inflation test data for cerebral arteries are used to evaluate the constitutive model. It is found to fit the mechanical response of uniaxial test well. There is a need for additional experimental data to further evaluate and develop this model. The constitutive model is implemented in commercial finite element analysis package for numerical computation. The numerical implementation is validated by analytical solutions. The numerical model is used for the study of arterial microstructural behavior in complex biomechanical procedure of angioplasty surgery

Attributions of emission-reduction and meteorological conditions to typical heavy pollution episodes in a cold metropolis, northeast China

Heavy pollution episodes frequently occurred in winter in northeast China due to the multiple anthropogenic emissions coupled with adverse meteorological conditions, which increased the difficulty of environmental pollution control. To better enact strategies for mitigating air pollution in the post-pandemic era, daily pollutant concentration monitoring and meteorological data were used to evaluate the changes and meteorological factors of air pollutants before (2019) and during (2020) the lockdown in Harbin City, northeast China. Moreover, typical pollution episodes under COVID-19 lockdown were identified, and their emission sources, meteorology conditions, and regional pollution transportation were analyzed. The results showed significant decreases in NO2, PM10 and CO, while O3 increased, and no differences in PM2.5 and SO2 during the lockdown compared with non-lockdown periods. It indicated that reduced activities of transportation resulted in reductions of NO2 concentrations by 16%, and stationary emission sources were less affected. Correlation between PM2.5 and O3 tended to change from positive to negative as the threshold of PM2.5 = 90 μg m−3, with the main controlling factor changed from their common gaseous precursors to meteorological conditions (temperature <0°C and wind speed <2 m s−1). Pollution days were concentrated in the COVID-19 lockdown period with PM2.5 as the primary pollutant. SO2 dominant pollution and PM2.5 dominant pollution were distinguished from six sustained heavy pollution events. PM2.5 and SO2 played essential roles in SO2 dominant pollution, which derived from local emissions of coal combustion and firework discharge. PM2.5 dominant pollution might be chemical transformed from coal burning, vehicle exhaust, and other secondary precursors, which was affected and aggravated by CO, NO2, high relative humidity and low wind speed affected by local emission and long-distance transport

Genome-Wide Association Studies Identified Three Independent Polymorphisms Associated with α-Tocopherol Content in Maize Kernels

Tocopherols are a class of four natural compounds that can provide nutrition and function as antioxidant in both plants and animals. Maize kernels have low α-tocopherol content, the compound with the highest vitamin E activity, thus, raising the risk of vitamin E deficiency in human populations relying on maize as their primary vitamin E source. In this study, two insertion/deletions (InDels) within a gene encoding γ-tocopherol methyltransferase, Zea mays VTE4 (ZmVTE4), and a single nucleotide polymorphism (SNP) located ∼85 kb upstream of ZmVTE4 were identified to be significantly associated with α-tocopherol levels in maize kernels by conducting an association study with a panel of ∼500 diverse inbred lines. Linkage analysis in three populations that segregated at either one of these three polymorphisms but not at the other two suggested that the three polymorphisms could affect α-tocopherol content independently. Furthermore, we found that haplotypes of the two InDels could explain ∼33% of α-tocopherol variation in the association panel, suggesting ZmVTE4 is a major gene involved in natural phenotypic variation of α-tocopherol. One of the two InDels is located within the promoter region and associates with ZmVTE4 transcript level. This information can not only help in understanding the underlying mechanism of natural tocopherol variations in maize kernels, but also provide valuable markers for marker-assisted breeding of α-tocopherol content in maize kernels, which will then facilitate the improvement of maize as a better source of daily vitamin E nutrition

Cardiovascular Autonomic Neuropathy Is an Independent Risk Factor for Left Ventricular Diastolic Dysfunction in Patients with Type 2 Diabetes

Aim. This study aimed to evaluate the association between cardiovascular autonomic neuropathy (CAN) and left ventricular diastolic dysfunction (LVDD) in type 2 diabetes patients. Methods. 315 type 2 diabetes patients from inpatients of Drum Tower Hospital were included and classified into no CAN (NCAN), possible CAN (PCAN), and definite CAN (DCAN) based on cardiovascular autonomic reflex tests. The left ventricular diastolic function was assessed by tissue Doppler imaging echocardiography. Results. The distribution of NCAN, PCAN, and DCAN was 11.4%, 51.1%, and 37.5%, respectively. The proportion of LVDD increased among the groups of NCAN, PCAN, and DCAN (39.4%, 45.3%, and 68.0%, = 0.001). Patients with DCAN had higher filling pressure ( / ratio) (10.9 ± 2.7 versus 9.4 ± 2.8, = 0.013) and impaired diastolic performance ( ) (6.8 ± 1.7 versus 8.6±2.4, = 0.004) compared with NCAN. CAN was found to be an independent risk factor for LVDD from the multivariate regression analysis (OR = 1.628, = 0.009, 95% CI 1.131-2.344). Conclusions. Our results indicated that CAN was an independent risk marker for the presence of LVDD in patients with diabetes. Early diagnosis and treatment of CAN are advocated for preventing LVDD in type 2 diabetes