Vascular calcification is closely associated with cardiovascular-related mortality,particularly high-risk of occurring this disease is in patients suffering from hypertension.Vascular calcification involves the active...Vascular calcification is closely associated with cardiovascular-related mortality,particularly high-risk of occurring this disease is in patients suffering from hypertension.Vascular calcification involves the active deposition of calcium and other mineral substances in the vascular wall.In blood vessels,intimal calcification is related to atherosclerosis,whereas medial calcification is a non-occlusive process that increases vascular stiffness and reduces vascular compliance.In the valves,calcification of the leaflets can change the mechanical properties of the tissue and result in stenosis.Cardiovascular diseases are being lead significant health risk worldwide and its estimated 30%of deaths.Synthetic drugs can help in the treatment of cardiovascular disease but they have limited efficacy and carry substantial risks.High risk and narrow margin of safety of synthetic drugs growing our interest to explore the different plants with specific medicinal properties in treatment of different cardiovascular disorders including hypertension,atherosclerosis,cardiac arrest and heart failure.Plants like Daucus carota,Nerium oleander,Amaranthus,Terminalia arjuna,and Picrorhiza kurroa contain phytochemicals like tea flavonoids,polyphenols,plant sterols,and terpenoids that can prevent low density lipoprotein cholesterol oxidation,inhibit cholesterol synthesis and promote vasodilation.Researchers has identified many medicinal herbs and their chemical components that show potential in alleviating vascular calcification via antioxidant mechanisms.In this study,we briefly discuss the role of vascular calcification in the pathophysiology of cardiac diseases.Utilizing the efficacy of these natural molecules will lead to the development of new treatment methods for chronic heart disease associated with vascular calcification.展开更多
A compliant tower is modeled as a partially dry, partially tapered, damped Timoshenko beam with the superstructure modeled as an eccentric tip mass, and a non-classical damped boundary at the base. The foundation is m...A compliant tower is modeled as a partially dry, partially tapered, damped Timoshenko beam with the superstructure modeled as an eccentric tip mass, and a non-classical damped boundary at the base. The foundation is modeled as a combination of a linear spring and a torsional spring, along with parallel linear and torsional dampers(Kelvin-Voigt model). The superstructure adds to the kinetic energy of the system without affecting the potential energy, thereby reducing the natural frequencies. The weight of the superstructure acts as an axial compressive load on the beam, reducing its natural frequencies further. The empty space factor due to the truss-type structure of the tower is included. The effect of shear deformation and rotary inertia are included in the vibration analysis; with the non-uniform beam mode-shapes being a weighted sum of the uniform beam mode-shapes satisfying the end condition. The weights are evaluated by the Rayleigh-Ritz(RR) method, and verified using finite element method(FEM). The weight of the superstructure acts as an axial compressive load on the beam. Kelvin-Voigt model of structural damping is included.A part of the structure being underwater, the virtual added inertia is included to calculate the wet natural frequencies. A parametric study is done for various magnitudes of tip mass and various levels of submergence. The computational efficiency and accuracy of the Rayleigh-Ritz method, as compared to the FEA, has been demonstrated. The advantage of using closed-form trial functions is clearly seen in the efficacy of calculating the various energy components in the RR method.展开更多
文摘Vascular calcification is closely associated with cardiovascular-related mortality,particularly high-risk of occurring this disease is in patients suffering from hypertension.Vascular calcification involves the active deposition of calcium and other mineral substances in the vascular wall.In blood vessels,intimal calcification is related to atherosclerosis,whereas medial calcification is a non-occlusive process that increases vascular stiffness and reduces vascular compliance.In the valves,calcification of the leaflets can change the mechanical properties of the tissue and result in stenosis.Cardiovascular diseases are being lead significant health risk worldwide and its estimated 30%of deaths.Synthetic drugs can help in the treatment of cardiovascular disease but they have limited efficacy and carry substantial risks.High risk and narrow margin of safety of synthetic drugs growing our interest to explore the different plants with specific medicinal properties in treatment of different cardiovascular disorders including hypertension,atherosclerosis,cardiac arrest and heart failure.Plants like Daucus carota,Nerium oleander,Amaranthus,Terminalia arjuna,and Picrorhiza kurroa contain phytochemicals like tea flavonoids,polyphenols,plant sterols,and terpenoids that can prevent low density lipoprotein cholesterol oxidation,inhibit cholesterol synthesis and promote vasodilation.Researchers has identified many medicinal herbs and their chemical components that show potential in alleviating vascular calcification via antioxidant mechanisms.In this study,we briefly discuss the role of vascular calcification in the pathophysiology of cardiac diseases.Utilizing the efficacy of these natural molecules will lead to the development of new treatment methods for chronic heart disease associated with vascular calcification.
文摘A compliant tower is modeled as a partially dry, partially tapered, damped Timoshenko beam with the superstructure modeled as an eccentric tip mass, and a non-classical damped boundary at the base. The foundation is modeled as a combination of a linear spring and a torsional spring, along with parallel linear and torsional dampers(Kelvin-Voigt model). The superstructure adds to the kinetic energy of the system without affecting the potential energy, thereby reducing the natural frequencies. The weight of the superstructure acts as an axial compressive load on the beam, reducing its natural frequencies further. The empty space factor due to the truss-type structure of the tower is included. The effect of shear deformation and rotary inertia are included in the vibration analysis; with the non-uniform beam mode-shapes being a weighted sum of the uniform beam mode-shapes satisfying the end condition. The weights are evaluated by the Rayleigh-Ritz(RR) method, and verified using finite element method(FEM). The weight of the superstructure acts as an axial compressive load on the beam. Kelvin-Voigt model of structural damping is included.A part of the structure being underwater, the virtual added inertia is included to calculate the wet natural frequencies. A parametric study is done for various magnitudes of tip mass and various levels of submergence. The computational efficiency and accuracy of the Rayleigh-Ritz method, as compared to the FEA, has been demonstrated. The advantage of using closed-form trial functions is clearly seen in the efficacy of calculating the various energy components in the RR method.
