The cost for covering active power losses makes a significant item in transmission system operators (TSO) annual budgets, and still it received limited attention in the existing literature. The focus ...of accurate power loss forecasting and procurement is of high increase during the past 2 years due to spikes in electricity prices, making the cost of covering the active power losses a dominant factor of TSO operational costs. This paper presents practical aspects of the highly accurate models for transmission loss forecast in the day ahead time frame for the Croatian transmission system. The contributions are two‐fold: 1) Practical insights into usable TSO data are provided, filling a critical research gap and a foundational literature review is established on transmission loss forecasting. 2) A novel method utilizing only electricity transit data as input which outperforms existing practices is presented. For this, several algorithms such as gradient boosted decision tree model (XGB), support vector regressors, multiple linear regression and fully connected feedforward artificial neural networks are developed, and implemented and validated on data obtained from the Croatian TSO. The results show that the XGB model outperforms current TSO model by 32% for 4 months of comparison and TSCNET's commercial solution by 25% during a year‐long testing period. The developed XGB model is also implemented as a software tool and put into everyday operation with the Croatian TSO.
This paper presents practical aspects of the of highly accurate models for transmission loss forecast in the day ahead time frame. In the first part of the paper, multiple sources of available data which could be used for developing the prediction models are discussed, while in the second part, a novel method is proposed based only on electricity transit data as inputs by using real data of the Croatian transmission system operators. The results show the model outperforms existing practices and commercially available solutions by at least 25% MAPE. The developed model is also implemented as a software tool and put into everyday operation with the Croatian transmission system operator.
Olive pomace is a valuable secondary raw material rich in polyphenols, left behind after the production of olive oil. The present study investigated the protective effect of a polyphenolic extract ...from olive pomace (OPE) on cell viability and antioxidant defense of cultured human HepG2 cells submitted to oxidative stress induced by
-butylhydroperoxide (tBOOH). The investigation considered possible matrix effects, impact of gastrointestinal digestion and cyclodextrin (CD) encapsulation. Pre-treatment of cells with OPE prevented cell damage and increased intracellular glutathione but did not affect the activity of glutathione peroxidase and superoxide dismutase. OPE matrix significantly enhanced cell protective effects of major antioxidants, such as hydroxytyrosol (HTS), while cyclodextrin encapsulation enhanced activity of OPE against intracellular reactive oxygen species (ROS) accumulation. The obtained results show that OPE is more potent antioxidant in comparison to equivalent dose of main polyphenols (HTS and TS) and that increasing solubility of OPE polyphenols by CD encapsulation or digestion enhances their potential to act as intracellular antioxidants. Antioxidative protection of cells by OPE was primarily achieved through direct radical-scavenging/reducing actions rather than activation of endogenous defense systems in the cell.
Process of transmission planning needs to provide the location and type of solution that will ensure quality and security of supply network users. Taking into account the stated requirements, the ...transmission network (TN) must have satisfactory electricity transmission capacities (TC) and it is necessary to determine the technical solutions at an acceptable financial cost. In this paper, a model will be presented how to determine the location and type of investment, taking into account the connection of future power plants, users, development plans of neighbouring countries and the energy strategy of Europe. The model evaluates the possibilities of implementation of high-temperature low sag conductors (HTLS) and compacted overhead transmission lines (OHL) on the existing infrastructure or construction of new transmission lines in the same right of way. The main idea of the presented model is to investigate the influence of a proposed investment based on measurement data taking into account losses and TC of the TN as important factors. In order to increase TC taking into consideration TN losses, a number of possible technical solutions will be investigated.
This paper presents an advanced model for monitoring losses on a 400 kV over-head transmission line (OHL) that can be used for measured data verification and loss assessment. Technical losses are ...unavoidable physical effects of energy transmission and can be reduced to acceptable levels, with a major share of technical losses on transmission lines being Joule losses. However, at 400 kV voltage levels, the influence of the electrical corona discharge effect and current leakage can have significant impact on power loss. This is especially visible in poor weather conditions, such as the appearance of fog, rain and snow. Therefore, loss monitoring is incorporated into exiting business process to provide transmission system operators (TSO) with the measure of losses and the accurate characterization of measured data. This paper presents an advanced model for loss characterization and assessment that uses phasor measurement unit (PMU) measurements and combines them with end-customer measurements. PMU measurements from the algorithm of differential protection are used to detect differential currents and angles, and this paper proposes further usage of these data for determining the corona losses. The collected data are further processed and used to calculate the amount of corona losses and provide accurate loss assessment and estimation. In each step of the model, cross verification of the measured and calculated data is performed in order to finally provide more accurate loss assessment which is incorporated into the current data acquisition and monitoring systems.
Increasing use of nano-enabled products provides many benefits in various industrial processes and medical applications, but it also raises concern about release of nanoparticles (NPs) into the ...environment and subsequent human exposure. While potential toxicity of individual NPs types has been well described in scientific literature, exposure and health-related effects of nanomixtures has been poorly described. This study aimed to evaluate the combined effect of silver (AgNP) and polystyrene NPs (PSNP) on the human macrophages. AgNP are one of the most commercialized NPs due to efficient antimicrobial activity, while PSNP are ubiquitous in terrestrial and aquatic environments due to plastic pollution and degradation of polystyrene-based products. Differentiated monocytic cell line THP-1 were used as an in vitro model of human macrophages. Multiple aspects of cellular response to AgNP-PSNP nanomixture were analyzed including cell death, induction of apoptosis, oxidative stress response, expression of pro- and anti-inflammatory cytokines, and nanomechanical properties of cells. NPs uptake was visualized by confocal microscopy and quantified using flow cytometry. Results show that nanomixture increased apoptosis and cell death, expression of IL-6, IL-8 and TNFa, oxidative stress and mitochondrial dysfunction in cells compared to AgNP and PSNP applied as single treatments, indicating mixture additive action. Anti-inflammatory cytokines IL1b, IL-4 and IL-10 were not affected by combined exposure compared to single NPs. Visualization of NPs uptake and internalization showed that AgNP and PSNP were localized mostly in cytoplasm, with small fraction of AgNP translocated into cell nuclei, which explain increased number of double-stranded DNA breaks following exposure of cells to AgNPs alone or in the mixture. Study outcomes represent clear warnings on the human co-exposure to AgNP and PSNP that needs to be implemented in risk assessment approaches towards toxic-free environment.
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•Response of human macrophages to nanomixture was evaluated.•Nanomixture consisted of silver (AgNP) and polystyrene nanoparticles (PSNP).•Nanomixture showed increased toxicity compared to AgNP and PSNP.•Nanomixture increased oxidative stress, apoptosis and inflammatory response in macrophages.
Safe and successful bioapplications of metallic nanoparticles depend on their physicochemical characteristics, in particular their surface properties. This study aimed to investigate how different ...surface functionalization of silver nanoparticles (AgNP) affect their interaction with mammalian liver cells with regard to cytotoxicity, genotoxicity and mechanism of cellular uptake. Differentially coated AgNP were prepared by surface functionalization using sodium bis(2-ethylhexyl)-sulfosuccinate (AOTAgNP), cetyltrimethylammonium bromide (CTABAgNP), poly(vinylpyrrolidone) (PVPAgNP), poly-l-lysine (PLLAgNP), and bovine serum albumin (BSAAgNP). Data showed varying toxic potential of differentially coated AgNP. All AgNP types demonstrated concentration dependent effects on cytotoxicity and genotoxicity in HepG2 cells. Cytotoxic potential of differentially coated AgNP followed the order of BSAAgNP > PLLAgNP > CTABAgNP > AOTAgNP > PVPAgNP. Exposure of HepG2 cells to non-cytotoxic concentrations (up to 10 mg Ag/L) of AgNP for 24 h induced primary DNA damage as evaluated by alkaline comet assay. The highest increase in both comet tail length and tail intensity was produced by PLLAgNP followed by AOTAgNP, while CTABAgNP appeared to be least damaging. The main uptake mechanisms of AgNP were macropinocytosis and clathrin-mediated endocytosis. The study findings contribute to the criteria that should be considered in evaluating the biocompatibility and safety of novel nanomaterials.
•Surface functionalization affects cellular toxicity and uptake of silver nanoparticles (AgNP).•All AgNP demonstrated dose response cyto- and genotoxicity in HepG2 cells.•All AgNP were taken up by macropinocytosis and clathrin-mediated endocytosis.
Although a very-low-calorie diet (VLCD) is considered safe and has demonstrated benefits among other types of diets, data are scarce concerning its effects on improving health and weight loss in ...severely obese patients. As part of the personalized weight loss program developed at the Duga Resa Special Hospital for Extended Treatment, Croatia, we evaluated anthropometric, biochemical, and permanent DNA damage parameters (assessed with the cytochalasin B-blocked micronucleus
assay-CBMN) in severely obese patients (BMI ≥ 35 kg m
) after 3-weeks on a 567 kcal, hospital-controlled VLCD. This is the first study on the permanent genomic (in)stability in such VLCD patients. VLCDs caused significant decreases in weight (loss), parameters of the lipid profile, urea, insulin resistance, and reduced glutathione (GSH). Genomic instability parameters were lowered by half, reaching reference values usually found in the healthy population. A correlation was found between GSH decrease and reduced DNA damage. VLCDs revealed susceptible individuals with remaining higher DNA damage for further monitoring. In a highly heterogeneous group (class II and III in obesity, differences in weight, BMI, and other categories) consisting of 26 obese patients, the approach demonstrated its usefulness and benefits in health improvement, enabling an individual approach to further monitoring, diagnosis, treatment, and risk assessment based on changing anthropometric/biochemical VLCD parameters, and CBMN results.
Imidacloprid is a neonicotinoid insecticide that acts selectively as an agonist on insect nicotinic acetylcholine receptors. It is used for crop protection worldwide, as well as for non-agricultural ...uses. Imidacloprid systemic accumulation in food is an important source of imidacloprid exposure. Due to the undisputable need for investigations of imidacloprid toxicity in non-target species, we evaluated the effects of a 28-day oral exposure to low doses of imidacloprid (0.06 mg/kg b. w./day, 0.8 mg/kg b. w./day and 2.25 mg/kg b. w./day) on cholinesterase activity, oxidative stress responses and primary DNA damage in the blood and brain tissue of male Wistar rats. Exposure to imidacloprid did not cause significant changes in total cholinesterase, acetylcholinesterase and butyrylcholinesterase activities in plasma and brain tissue. Reactive oxygen species levels and lipid peroxidation increased significantly in the plasma of rats treated with the lowest dose of imidacloprid. Activities of glutathione-peroxidase in plasma and brain and superoxide dismutase in erythrocytes increased significantly at the highest applied dose. High performance liquid chromatography with UV diode array detector revealed the presence of imidacloprid in the plasma of all the treated animals and in the brain of the animals treated with the two higher doses. The alkaline comet assay results showed significant peripheral blood leukocyte damage at the lowest dose of imidacloprid and dose-dependent brain cell DNA damage. Oral 28-day exposure to low doses of imidacloprid in rats resulted in detectable levels of imidacloprid in plasma and brain tissue that directly induced DNA damage, particularly in brain tissue, with slight changes in plasma oxidative stress parameters.
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•Male Wistar rats were orally exposed to low doses of imidacloprid for 28 days.•Detectable levels of imidacloprid were found in plasma and brain tissue.•Imidacloprid induced slight changes in oxidative stress parameters.•Primary DNA damage was dose-dependent in brain cells.
Skin protection against ultraviolet (UV) radiation is necessary to reduce sunburn damage (erythema) and has been recognized as an important preventive measure against the development of cancer. Many ...sun-blocking pharmaceutical products are based on titanium dioxide nanomaterials (TiO
2
NMs) due to their UV barrier properties. This study aimed to assess if the UV protective efficiency of TiO
2
NMs depends on their shape. We prepared TiO
2
nanowires (TNW), TiO
2
nanotubes (TNT), and TiO
2
nanoplates (TNP) and tested their effects on human keratinocytes before and after UVB irradiation under in vitro exposure settings. The UVB radiation was applied at the dose equivalent to the UV component observed in one medial erythemal dose. The biological effects of TiO
2
NMs on nonirradiated and UVB-irradiated keratinocytes were observed by means of cell viability, genotoxicity, and inflammatory response. The obtained results clearly showed that the effects of TiO
2
NMs in vitro, either cytotoxic or protective, depend on their shape. These observations highlight the beneficial properties of nanomaterials that can improve the quality and efficacy of nano-enabled products only if the safe-by-design concept has been implemented during the innovation process.
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