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Andrei Damian, Marian Alexandru and Tiberiu Catalina

Abstract

In view of the recent preoccupation at worldwide level, for the integration of the solar systems components within the building skin, we made a numerical investigation in order to assess the opportunity to implement a long string of solar panels along a horizontal or vertical building surface.The study analyses deals with the phenomenon of self-shading, which appears in the case of medium and large solar systems that use solar panels placed one behind the other, along the same row (individual string), but also under the shape of parallel rows (parallel strings). The study creates a mathematical instrument for the evaluation of the shaded surface depending on the location of the panels and the relative position of the Sun. The shading-caused energy loss is analysed along the one-year period, for each of the 12 months, while the panels are considered either placed on a horizontal surface such as a building terrace, or on a vertical surface, such as a building facade. The simulations are made for six Romanian cities located in different climatic zones, characterized by different levels of solar radiation.

Open access

Alexandru Bobe, Wladimir G. Boskoff and Marian G. Ciucă

Abstract

In this article we introduce three centro-affine invariant functions in Minkowski spaces. Tzitzeica curves and Tzitzeica surfaces may be defined in this new context. Our main results allow us to understand the connections between Tzitzeica curves and surfaces in Minkowski spaces and the original Tzitzeica curves and surfaces from the Euclidian space

Open access

Roxana Buzas, Alexandru Florin Rogobete, Sonia Elena Popovici, Tudor Mateescu, Teodora Hoinoiu, Virgiliu-Bogdan Sorop, Tiberiu Bratu, Marian Ticlea, Calin Marius Popoiu and Dorel Sandesc

Abstract

Worldwide, cardiovascular diseases (CVDs) represent one of the main causes of morbidity and mortality, and acute coronary syndromes are responsible for a large number of sudden cardiac deaths. One of the main challenges that still exist in this area is represented by the early detection and targeted monitoring of the pathophysiology involved in CVDs. During the last couple of years, researchers have highlighted the importance of molecular and epigenetic mechanisms involved in the initiation and augmentation of CVDs, culminating in their most severe form represented by acute myocardial infarction. One of the most studied molecular factors involved in this type of pathology is represented by nuclear transcription factor kappa B (NF-κB), as well as the involvement of microRNAs (miRNAs). It has been suggested that miRNAs can also be involved in the complex process of atheromatous plaque vulnerabilization that leads to an acute cardiac event. In this review paper, we describe the most important molecular mechanisms involved in the pathogenesis of CVDs and atheromatous plaque progression and vulnerabilization, which include molecular mechanisms dependent on NF-κB. For this paper, we used international databases (PubMed and Scopus). The keywords used for the search were “miRNAs biomarkers”, “miRNAs in cardiovascular disease”, “NF-κB in cardiovascular disease”, “molecular mechanism in cardiovascular disease”, and “myocardial NF-κB mechanisms”. Numerous molecular reactions that have NF-κB as a trigger are involved in the pathogenesis of CVDs. Moreover, miRNAs play an important role in initiating and aggravating certain segments of CVDs. Therefore, miRNAs can be used as biomarkers for early evaluation of CVDs. Furthermore, in the future, miRNAs could be used as a targeted molecular therapy in order to block certain mechanisms responsible for inducing CVDs and leading to acute cardiovascular events.