New reactive power compensation strategies for railway infrastructure capacity increasing

In AC railway electrification systems, the impact of reactive power flow in the feeding voltage magnitude is one aspect contributing to the quality of supply degradation. Specifically, this issue results in limitations in the infrastructure capacity, either in the maximum number of trains and in maximum train power. In this paper, two reactive power compensation strategies are presented and compared, in terms of the theoretical railway infrastructure capacity. The first strategy considers a static VAR compensator, located in the neutral zone and compensating the substation reactive power, achieving a maximum capacity increase up to 50% without depending on each train active power. The second strategy adapts each train reactive power, achieving also a capacity increase around 50%, only with an increase of the train apparent power below 10%. With a smart metering infrastructure, the implementation of such compensation strategy is viable, satisfying the requirements of real-time knowledge of the railway electrification system state. Specifically, the usage of droop curves to adapt in real time the compensation scheme can bring the operation closer to optimality. Thus, the quality of supply and the infrastructure capacity can be increased with a mobile reactive power compensation scheme, based on a smart metering framework.This research was funded by FCT (Fundação Ciência e Tecnologia) under grant PD/BD/128051/2016.This research is also associated with the Shift2Rail In2Stempo project (grant 777515)

Association between GSTM1, GSTT1, and GSTP1 variants and the risk of end stage renal disease

Introduction: There are some evidences indicating DNA damage by oxidant and mutant agents has an essential role in the chronic renal failure and end stage renal disease (ESRD). To investigate the possible association of GSTs variants with ESRD, we investigated the frequency of GST- T1, M1, and P1 genotypes, and the level of malondialdehyde (MDA) in patients with ESRD.Materials and methods: The present case-control study consisted of 136 ESRD patients treated with maintenance hemodialysis and 137 gender- and age-matched, unrelated healthy controls from the population of west of Iran. The GST- T1, M1, and P1 genotypes were determined in all individuals using multiplex-PCR and PCR-RFLP. The level of MDA was measured by high-performance liquid chromatography (HPLC).Results: We found that GSTM1 and GSTT1 null genotypes (GSTT1-/GSTM1-) increased the risk of ESRD by 1.8 times (p<0.001) and the increased risk of ESRD for GSTM-null (T1+-M1-) genotype was 3.04 times (p=0.002). ESRD patients carriers the GST (GSTM1-null+GSTT1-null+GST-null) genotypes compared to GST normal genotype increased the risk of ESRD by 3.3 (p<0.001) times. ESRD patients carriers of GST-null, GSTM1-null, and GSTT1-null genotypes had greater MDA concentration compared with the same genotypes of control subjects. Our results indicated that the GST-null allele (GSTT1-null/GSTM1-null) is a risk factor for ESRD and carriers of this allele have high levels of MDA.Conclusion: Our findings indicate that oxidative stress, impairment of the antioxidant system and abnormal lipid metabolism may play a role in the pathogenesis and progression of ESRD and its related complications. These data suggest that patients with ESRD are more susceptible to vascular diseases

Biochemical and genetic analysis of butyrylcholinesterase (BChE) in a family, due to prolonged neuromuscular blockade after the use of succinylcholine

Butyrylcholinesterase (BChE) is a plasma enzyme that catalyzes the hydrolysis of choline esters, including the muscle-relaxant succinylcholine and mivacurium. Patients who present sustained neuromuscular blockade after using succinylcholine usually carry BChE variants with reduced enzyme activity or an acquired BChE deficiency. We report here the molecular basis of the BCHE gene underlying the slow catabolism of succinylcholine in a patient who underwent endoscopic nasal surgery. We measured the enzyme activity of BChE and extracted genomic DNA in order to study the promoter region and all exons of the BCHE gene of the patient, her parents and siblings. PCR products were sequenced and compared with reference sequences from GenBank. We detected that the patient and one of her brothers have two homozygous mutations: nt1615 GCA > ACA (Ala539Thr), responsible for the K variant, and nt209 GAT > GGT (Asp70Gly), which produces the atypical variant A. Her parents and two of her brothers were found to be heterozygous for the AK allele, and another brother is homozygous for the normal allele. Sequence analysis of exon 1 including 5′UTR showed that the proband and her brother are homozygous for –116GG. The AK/AK genotype is considered the most frequent in hereditary hypocholinesterasemia (44%). This work demonstrates the importance of defining the phenotype and genotype of the BCHE gene in patients who are subjected to neuromuscular block by succinylcholine, because of the risk of prolonged neuromuscular paralysis

Dental caries in primary and permanent teeth in children's worldwide, 1995 to 2019: a systematic review and meta-analysis

Background: Early childhood caries (ECC) is a type of dental caries in the teeth of infants and children that is represented as one of the most prevalent dental problems in this period. Various studies have reported different types of prevalence of dental caries in primary and permanent teeth in children worldwide. However, there has been no comprehensive study to summarize the results of these studies in general, so this study aimed to determine the prevalence of dental caries in primary and permanent teeth in children in different continents of the world during a systematic review and meta-analysis. Methods: In this review study, articles were extracted by searching in the national and international databases of SID, MagIran, IranMedex, IranDoc, Cochrane, Embase, ScienceDirect, Scopus, PubMed, and Web of Science (ISI) between 1995 and December 2019. Random effects model was used for analysis and heterogeneity of studies was evaluated by using the I2 index. Data were analyzed by using the Comprehensive Meta-Analysis (Version 2) software. Findings: In this study, a total of 164 articles (81 articles on the prevalence of dental caries in primary teeth and 83 articles on the prevalence of dental caries in permanent teeth) were entered the meta-analysis. The prevalence of dental caries in primary teeth in children in the world with a sample size of 80,405 was 46.2% (95% CI: 41.6–50.8%), and the prevalence of dental caries in permanent teeth in children in the world with a sample size of 1,454,871 was 53.8% (95% CI: 50–57.5%). Regarding the heterogeneity on the basis of meta-regression analysis, there was a significant difference in the prevalence of dental caries in primary and permanent teeth in children in different continents of the world. With increasing the sample size and the year of study, dental caries in primary teeth increased and in permanent teeth decreased. Conclusion: The results of this study showed that the prevalence of primary and permanent dental caries in children in the world was found to be high. Therefore, appropriate strategies should be implemented to improve the aforementioned situation and to troubleshoot and monitor at all levels by providing feedback to hospitals

Gold Metallization of Silicon by Galvanic Displacement

There are several microelectronic processes which are based on gold due to its unique physical and chemical properties. Adhesion of gold films which are deposited by galvanic displacement is investigated by microindentation measurements. For investigation, load-displacement tests are performed on gold nanostructures which are deposited onto mono (100) and polycrystalline silicon in sulfite solutions. Composite hardness model for soft film on hard substrate is used to analyze the results. Gold films growth and composite Vickers microhardness are influenced by the adhesion of the gold film to silicon, as a function of different electrolytes and silicon substrates. The higher composite hardness and more extended deformation zone at the film/substrate lead to stronger adhesion. For the same film thickness, the composite hardness of films which are deposited onto mono silicon is higher than films on poly silicon. The effect of cysteine as additive on adhesion and microhardness measurements is emphasized

Nanostructured Gold For Immobilization Of Thioaniline Functionalized Glucose Oxidase And Au Nanoparticles By Electropolymerization

Sensors are devices composed of an active sensing material with a signal transducer. Electrochemical sensors have more advantages over the others because the electrodes can sense the analyte that is present in the host without doing any damage to the host system. The immobilization of a protein on a metallic transducer can be a crucial step in the development of bionanodevices that find applications in the field of biomaterials, biocoatings, biofuel cells, etc. In the present study, we show the immobilization by electropolymerization of thioaniline functionalized glucose oxidase and Au nanoparticles on nanostructured gold films prepared by electrodeposition and compared to sputtered gold. This enzyme is employed in the preparation of biosensors of biomedical interest. The goodness of the Au film for enzyme binding is evaluated by comparison of the enzyme activity and of the interval of linearity for the determination of glucose concentration