Tallinn University of Technology

About: Tallinn University of Technology is a education organization based out in Tallinn, Estonia. It is known for research contribution in the topics: European union & Computer science. The organization has 3688 authors who have published 10313 publications receiving 145058 citations. The organization is also known as: Tallinn Technical University & Tallinna Tehnikaülikool.

Greenhouse gas emission reduction perspectives in the Baltic States in frames of EU energy and climate policy

Abstract: The goal of this paper is to estimate the perspectives of the Baltic States: Estonia, Latvia and Lithuania on meeting the new European Union climate commitments, i.e., to reduce greenhouse gas emissions by 20% to the year 2020 in comparison with 1990. This ambitious target could be reached based on other EU climate and energy package commitments: increase of the share of renewables and improvement of energy efficiency as tools for fulfilling the GHG emissions reduction target. The paper gives an overview on the current situation and future plans of the Baltic States in the field of energy efficiency, consumption of renewables and reduction of GHG emissions.

Towards Efficient Wireless Body Area Network Using Two-Way Relay Cooperation

Abstract: The fabrication of lightweight, ultra-thin, low power and intelligent body-borne sensors leads to novel advances in wireless body area networks (WBANs). Depending on the placement of the nodes, it is characterized as in/on body WBAN; thus, the channel is largely affected by body posture, clothing, muscle movement, body temperature and climatic conditions. The energy resources are limited and it is not feasible to replace the sensor's battery frequently. In order to keep the sensor in working condition, the channel resources should be reserved. The lifetime of the sensor is very crucial and it highly depends on transmission among sensor nodes and energy consumption. The reliability and energy efficiency in WBAN applications play a vital role. In this paper, the analytical expressions for energy efficiency (EE) and packet error rate (PER) are formulated for two-way relay cooperative communication. The results depict better reliability and efficiency compared to direct and one-way relay communication. The effective performance range of direct vs. cooperative communication is separated by a threshold distance. Based on EE calculations, an optimal packet size is observed that provides maximum efficiency over a certain link length. A smart and energy efficient system is articulated that utilizes all three communication modes, namely direct, one-way relay and two-way relay, as the direct link performs better for a certain range, but the cooperative communication gives better results for increased distance in terms of EE. The efficacy of the proposed hybrid scheme is also demonstrated over a practical quasi-static channel. Furthermore, link length extension and diversity is achieved by joint network-channel (JNC) coding the cooperative link.

Effect of methionine-35 oxidation on the aggregation of amyloid-β peptide.

Abstract: Aggregation of Aβ peptides into amyloid plaques is considered to trigger the Alzheimer’s disease (AD), however the mechanism behind the AD onset has remained elusive It is assumed that the insoluble Aβ aggregates enhance oxidative stress (OS) by generating free radicals with the assistance of bound copper ions The aim of our study was to establish the role of Met35 residue in the oxidation and peptide aggregation processes Met35 can be readily oxidized by H 2 O 2 The fibrillization of Aβ with Met35 oxidized to sulfoxide was three times slower compared to that of the regular peptide The fibrils of regular and oxidized peptides looked similar under transmission electron microscopy The relatively small inhibitory effect of methionine oxidation on the fibrillization suggests that the possible variation in the Met oxidation state should not affect the in vivo plaque formation The peptide oxidation pattern was more complex when copper ions were present: addition of one oxygen atom was still the fastest process, however, it was accompanied by multiple unspecific modifications of peptide residues Addition of copper ions to the Aβ with oxidized Met35 in the presence of H 2 O 2 , resulted a similar pattern of nonspecific modifications, suggesting that the one-electron oxidation processes in the peptide molecule do not depend on the oxidation state of Met35 residue Thus, it can be concluded that Met35 residue is not a part of the radical generating mechanism of Aβ–Cu(II) complex

Elevated blood plasma antioxidant status is favourable for achieving IVF/ICSI pregnancy.

Abstract: The aim of the study was to determine the roles of intrafollicular and systemic oxidative stress and antioxidant response in ovarian stimulation and intracytoplasmic sperm injection (ICSI) outcomes. For this purpose, 102 ICSI patients undergoing controlled ovarian stimulation were enrolled and samples were collected on the day of follicle puncture. Total peroxide (TPX) concentrations and total antioxidant response (TAR) were measured in follicular fluid and blood plasma, and an oxidative stress index (OSI) was calculated based on these two parameters. Urinary concentrations of 8-iso-prostaglandin F2a (F2IsoP) were measured. Elevated intrafollicular oxidative stress was positively correlated with ovarian stimulation outcome: less FSH per retrieved oocyte was used, more oocytes were collected and higher serum oestradiol concentrations were measured in patients with higher follicular OSI. However, high urinary F2IsoP related to lower embryo quality and F2IsoP was also elevated in smoking patients. Patients with endometriosis had lower follicular antioxidant status. Most importantly, higher systemic blood TAR was significantly favourable for achieving clinical pregnancy (P=0.03). In conclusion, the findings suggest clear associations between oxidative stress, antioxidant status and several aspects of ovarian stimulation and IVF/ICSI outcome, including pregnancy rate. Several oxygen-dependent biochemical reactions produce reactive oxygen species as by-products that may eventually lead to oxidative stress, which is detrimental to cells and tissues. Total antioxidant status, on the other hand, comprises several agents that balance the excess of these reactive oxygen species and reduce potential damage to the body. The aim of the current work was to study this balance in 102 patients participating in an ICSI programme and to examine the degree to which total peroxide content and antioxidant status influence infertility and pregnancy outcome. During the study, several tests were performed to characterize oxidative stress levels in ovarian follicular fluid, blood plasma and urine. We found a significantly higher oxidative stress environment in the ovary when compared with blood plasma. This suggests a prominent role of oxidative stress in the ovaries of these patients. The elevated oxidative stress levels were correlated to a higher number of oocytes that could be obtained via the procedure and to a lower amount of FSH needed to mature the oocytes, suggesting that oxidative stress, to some degree, is favourable for hormone stimulation outcome. A high level of lipid peroxidation products in the urine, another marker of oxidative stress, was observed in smokers and this marker was elevated in patients with embryos that had lower developmental potential. A higher overall antioxidant status in blood plasma was advantageous for achieving pregnancy.