Molecular Dynamic Simulation Model for the Growth of Thin Films in The Structure Zone Model

A two dimensional molecular dynamic (atomistic) simulation model was used to investigate the relationship between the nano-structure and the deposition parameters; namely, substrate temperature, deposition rate, angle of incidence, surface roughness. Qualitative agreements with the predictions of the structure zone model (SZM) and the theoretical results of Srolovitze and coworkers (1988), as well as expectations through changes in the activated processes during film growth due to changes in deposition parameters (Grovenor and coworkers (1984)) are obtained. It is shown that by enhancing the atomic mobility (i.e., increasing the substrate temperature or/and lowering the deposition rate) films of higher density with fewer voids are produced. By increasing the deposition angle, the nano-structure of the film changes from a dense film with few voids, to a nano-structure with columns/boundless inclined with the same angle ( β ) towards the incidence atoms with elongated voids. The angle β increases with increasing the deposition angle (α ), and in agreement with the tangent rule (Dirks and Leamy (1977)). The angle of bundles (or the angle of the formation of the voids between atomic bundles), and columnar structure are caused by shadowing effects. Results showed that β decreases slowly with increasing surface mobility (i.e., increasing the substrate temperature or/and reducing the deposition rate). In general, the model provides almost all predicted results and agrees well with observation

Medicinal plants and atherosclerosis: A review on molecular aspects

Atherosclerosis is an inflammatory vascular disease that is characterized by progressive accumulation of cholesterol in the arterial walls and it is a major cause of cardiovascular disease. Issues related to the side effects of synthetic drugs have in recent times, led to the misuse of drugs, a lack of patient consultations, and consequently, a disruption in meticulous disease control. Therefore, a new insight into medicinal plants has recently emerged and much research has been conducted on these herbs in an attempt to prepare novel naturally based drugs. The aim of this review article was to scrutinize the molecular mechanisms of medicinal plants possessing effectiveness against atherosclerosis. To conduct the review, electronic searches were performed to retrieve potentially relevant publications, indexed within internet databases and reference textbooks concerning the effects and underlying molecular mechanisms of plants or their constituents used to treat atherosclerosis. Overall, medicinal plants facilitate atherosclerosis treatment through a variety of mechanisms which include the regulation of expression of inflammatory factors, stimulation of peroxisome proliferator-activated receptors (PPARs), inhibition of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMG-CoA reductase), promotion of ATP-binding cassette transporter A1 (ABCA1) as well as ATP-binding cassette transporter G (ABCG), facilitation of adiponectin activity, reduction of sterol regulatory element-binding proteins (SREBPs) and antioxidant activity. An increased perception of these herbal mechanistic links is an important prelude to the design of novel plant based drugs