Regulatory Agent Research Articles

La compra eficiente en los territorios: un gran reto para el mercado de compra pública colombiano en un ambiente ampliamente regulado

The public procurement market is consolidated as the new paradigm to understand transactions between public authorities and the private sector to meet their needs. This makes the economic perspective of this discipline revolve around providing measures that seek the efficiency of the market. This text argues that such efficiency is achieved when the precise roles of the regulatory agent and the purchasing agent whose objectives are different but their harmonious collaboration is what generates the environment of commercial normality are identified and assigned; this position is explained through an analysis of the Colombian case with the risks to efficiency represented by a regulation directed exclusively from the central sector and an institutional measure is proposed to mitigate them.

FTO promotes gefitinib-resistance by enhancing PELI3 expression and autophagy in non-small cell lung cancer

The established recognition of N6-methyladenosine (m6A) modification as an indispensable regulatory agent in human cancer is widely accepted. However, the understanding of m6A's role and the mechanisms underlying its contribution to gefitinib resistance is notably limited. Herein, using RT-qPCR, Western blot, Cell proliferation and apoptosis, as well as RNA m6A modification assays, we substantiated that heightened FTO (Fat Mass and Obesity-associated protein) expression substantially underpins the emergence of gefitinib resistance in NSCLC cells. This FTO-driven gefitinib resistance is hinged upon the co-occurrence of PELI3 (Pellino E3 Ubiquitin Protein Ligase Family Member 3) expression and concurrent autophagy activation. Manipulation of PELI3 expression and autophagy activation, including its attenuation, was efficacious in both inducing and overcoming gefitinib resistance within NSCLC cells, as validated in vitro and in vivo. In summary, this study has successfully elucidated the intricate interplay involving FTO-mediated m6A modification, its consequential downstream effect on PELI3, and the concurrent involvement of autophagy in fostering the emergence of gefitinib resistance within the therapeutic context of NSCLC.

TIPRL, a Potential Double-edge Molecule to be Targeted and Re-targeted Toward Cancer.

The target of rapamycin (TOR) proteins exhibits phylogenetic conservation across various species, ranging from yeast to humans, and are classified as members of the phosphatidylinositol kinase (PIK)-related kinase family. Multiple serine/threonine (Ser/Thr) protein phosphatases (PP)2A, PP4, and PP6, have been recognized as constituents of the TOR signaling pathway in mammalian cells. The protein known as TOR signaling pathway regulator-like (TIPRL) functions as a regulatory agent by impeding the activity of the catalytic subunits of PP2A. Various cellular contexts have been postulated for TIPRL, encompassing the regulation of mechanistic target of rapamycin (mTOR) signaling, inhibition of apoptosis and biogenesis, and recycling of PP2A. According to reports, there has been an observed increase in TIPRL levels in several types of carcinomas, such as non-small-cell lung carcinoma (NSCLC) and hepatocellular carcinomas (HCC). This review aims to comprehensively examine the significance of the Tor pathway in regulating apoptosis and proliferation of cancer cells, with a specific focus on the role of TOR signaling and TIPRL in cancer.

Estimation of Dissolved Organic Carbon Using Sentinel-2 in the Eutrophic Lake Ebinur, China

Dissolved organic carbon (DOC) in lakes, as a regulatory agent and light-absorbing compound, is a key component of the global carbon cycling in lacustrine ecosystems. Hence, continuous monitoring of the DOC concentration in arid regions is extremely important. This study utilizes the QAA-CDOM semi-analytical model, which has good accuracy in retrieving the CDOM (colored dissolved organic matter) concentration of Lake Ebinur. We chose to invert the CDOM time-series data from May to October during the 2018–2022 period. A DOC estimation model was then established using the linear regression approach based on the CDOM inversion data and the field DOC measurements. In general, the DOC concentration in Lake Ebinur exhibited an increasing trend from 2018 to 2022, typically lower in May and higher in June. When comparing the average values of DOC in Lake Ebinur for the same months across different years, it can be observed that the month of September exhibits the greatest variability, whereas June shows the least variability. In sum, this study successfully retrieved CDOM concentrations for a saline lake within an arid region and developed a DOC estimation model, thereby providing a reference for investigating carbon cycling in typical lakes of arid areas.

Endogenous bank regulation and supervision: Long term implications

The role of bank regulation and supervision (RS) on financial stability and welfare has been subject to ongoing research, especially since the Great Recession. RS is expected to help eliminate the adverse selection and moral hazard problems that are abundant in financial transactions. In this paper, we present a general equilibrium model that is augmented by either a bank regulatory and supervisory agent who chooses the level of RS by maximizing bank profits, or by a macroprudential agent who minimizes non-performing loans (NPL). We compare the long-term outcomes of these scenarios and show that minimizing NPL is feasible for a larger and economically more viable range of parameter values than the alternatives. Moreover, for a comparable set of parameter combinations, the optimal choice of RS that minimizes NPL leads to both higher levels of steady state income and lower interest spreads as compared to RS that maximizes bank profits.

Can Pheromones Contribute to Phylogenetic Hypotheses? A Case Study of Chrysomelidae.

Pheromones mediate species-level communication in the search for mates, nesting, and feeding sites. Although the role of pheromones has long been discussed by various authors, their existence was not proven until the mid-twentieth century when the first sex pheromone was identified. From this finding, much has been speculated about whether this communication mechanism has acted as a regulatory agent in the process of speciation, competition, and sexual selection since it acts as an intraspecific barrier. Chrysomelidae is one of the major Phytophaga lineages, with approximately 40,000 species. Due to this immense diversity the internal relationships remain unstable when analyzed only with morphological data, consequently recent efforts have been directed to molecular analyses to establish clarity for the relationships and found their respective monophyly. Therefore, our goals are twofold 1) to synthesize the current literature on Chrysomelidae sex pheromones and 2) to test whether Chrysomelidae sex pheromones and their chemical structures could be used in phylogenetic analysis for the group. The results show that, although this is the first analysis in Chrysomelidae to use pheromones as a phylogenetic character, much can be observed in agreement with previous analyses, thus confirming that pheromones, when known in their entirety within lineages, can be used as characters in phylogenetic analyses, bringing elucidation to the relationships and evolution of organisms.

Prognostic Significance of PD-L2 Expression in Association with Neutrophil-to-Lymphocyte Ratio in Urothelial Carcinoma of the Bladder.

The prognostic significance of tumoral programmed death-ligand 2 (PD-L2) expression in urothelial bladder cancer (UBCs) is under-investigated , although it can potentially to become a regulatory agent of cancer immunity. In the search for supporting biomarkers, the neutrophil-to-lymphocyte ratio (NLR) as a readily available surrogate marker of immune status has been associated with clinical outcomes and other prognostic factors in various types of cancer. Here we evaluate the prognostic ability of baseline NLR in addition to PD-L2 expression in bladder cancer. We used a retrospective cohort of UBCs patients from the authors' institutions. We classified patients according to their PD-L2 and NLR levels. We associated the prognostic outcome of each group with disease-free survival (DFS) and overall survival (OS). Thirty patients had a tumor with positive PD-L2 expression. We found no significant correlation between PD-L2 expression and NLR. PD-L2 status failed to provide a significant prognostic impact (disease-free survival [DFS] and overall survival [OS] rate at 5 years, 42.85% in PD-L2-high versus 65.75% in PD-L2-low patients; p = 0.057, 42.85% in PD-L2-high patients versus 62.5% in PD-L2-low patients; p = 0.112, respectively). NLR status also failed to exhibit a significant prognostic impact (DFS and OS rate at 5 years, 44.44% in PD-L2-high versus 66.66% in PD-L2-low patients; p = 0.232, 55.55% in PD-L2-high versus 71.43% in PD-L2-low patients; P = 0.894, respectively). When PD-L2 status and NLR status were combined, the NLR-low and PD-L2-low were significant factors to predict a favorable disease-free survival (hazard ratio, 4.525 [95% confidence interval, 1.020 to 20.080]; P = 0.047. However, the multivariate analysis failed to show it as an independent factor. These findings suggest that the prognostic impact of PD-L2 expression could be affected by the NLR status.

Truncated-semaphorin3A is a potential regulatory molecule to restore immune homeostasis in immune-mediated diseases.

Regulatory molecules have recently been recognized for their beneficial effects in the treatment of immune-mediated diseases, rather than using cytotoxic immune-suppressing drugs, which are associated with many unwanted side effects. Semaphorin3A (sema3A), a unique regulatory master of the immune system, was shown to be decreased in the serum of systemic lupus erythematosus (SLE) patients, in association with disease severity. Later, we were able to show its extremely beneficial effect in treating lupus nephritis in the NZB/W mice model. The mechanisms by which sema3A maintains its regulatory effect is by binding the regulatory receptor CD72 on B cells, thereby reducing the threshold of BCR signaling on B cells and reducing the production of pro-inflammatory cytokines. The aim of this study was to generate a stable sema3A molecule, easy to produce with a higher binding capacity to CD72 receptor rather than to Neuropilin-1 (NRP-1) receptor, which is expressed in many cell types. Using the crystallographic structure of parental sema3A, we synthesized a new secreted (shorter) sema3A derivative, which we called truncated sema3A (T-sema3A). The new molecule lacked the NRP-1 binding domain (the C-terminal site) and has an artificial dimerization site at position 257 (serine residue was exchanged with a cysteine residue). To facilitate the purification of this molecule we added Histidine epitope tag in frame upstream to a stop codon. This construct was transfected using a viral vector to 293HEK cells to generate cells stably expressing T-sema3A. T-sema3A is shown to be with a higher binding ability to CD72 than to NRP-1 as demonstrated by a homemade ELISA. In addition, T-sema3A was shown to be a regulatory agent which can induce the expression of IL-10 and TGF-β and reduce the secretion of pro-inflammatory cytokines such as IL-6, IFN-γ, and IL-17A from human T and B-lymphocytes. Keeping this in mind, T-sema3A is highly effective in maintaining immune homeostasis, therefore, becoming a potential agent in restoring the regulatory status of the immune system in immune-mediated diseases.

Disclosure policy design and regulatory agent behavior

AbstractMandatory disclosure promotes self‐regulation of product quality but may also provide incentives for firms to manipulate disclosed information. Collection of quality information by inspectors protects against direct manipulation, but firms may attempt to unduly influence inspectors. In Las Vegas, Nevada, food‐service health inspections are numerically scored, with health code violations from three categories carrying prescribed demerit amounts. For disclosure however, numeric scores are coarsened into letter grades, which may encourage lobbying of inspectors to under‐report violations near threshold scores. Beginning in 2013, the demerit amount prescribed for each good‐practices violation was reduced from 1 to 0; whereas the letter‐grade scale and penalties prescribed for major and critical violations (3 and 5 demerits each) remained unchanged. Exploiting this removal of scoring implications from good‐practices violations, coupled with the discontinuous punishment severity inherent in letter‐grade disclosure, I find that inspectors significantly under‐reported good‐practices violations prior to 2013—by 31%–90% in some cases—when those violations were likely to affect letter grades. Without careful design, disclosure policies supplementing inspection programs may inadvertently undermine the regulatory efforts they were meant to support.

Manipulating chromatin architecture in C. elegans

BackgroundNucleosome-mediated chromatin compaction has a direct effect on the accessibility of trans-acting activators and repressors to DNA targets and serves as a primary regulatory agent of genetic expression. Understanding the nature and dynamics of chromatin is fundamental to elucidating the mechanisms and factors that epigenetically regulate gene expression. Previous work has shown that there are three types of canonical sequences that strongly regulate nucleosome positioning and thus chromatin accessibility: putative nucleosome-positioning elements, putative nucleosome-repelling sequences, and homopolymeric runs of A/T. It is postulated that these elements can be used to remodel chromatin in C. elegans. Here we show the utility of such elements in vivo, and the extreme efficacy of a newly discovered repelling sequence, PRS-322.ResultsIn this work, we show that it is possible to manipulate nucleosome positioning in C. elegans solely using canonical and putative positioning sequences. We have not only tested previously described sequences such as the Widom 601, but also have tested additional nucleosome-positioning sequences: the Trifonov sequence, putative repelling sequence-322 (PRS-322), and various homopolymeric runs of A and T nucleotides.ConclusionsUsing each of these types of putative nucleosome-positioning sequences, we demonstrate their ability to alter the nucleosome profile in C. elegans as evidenced by altered nucleosome occupancy and positioning in vivo. Additionally, we show the effect that PRS-322 has on nucleosome-repelling and chromatin remodeling.

Cell viability and collagen metabolism of MCF-7 breast cancer cells are affected by carbon monoxide released from CORM-2.

Carbon monoxide (CO), despite its reputation as a deadly poison, is being recognized as a powerful physiological regulatory agent with potential anti-cancer properties. To harness the potential of CO towards a safe therapy, CO-Releasing Molecules (CO-RMs) have been developed. In the present study, the effects of tricarbonyldichlororuthenium(II) dimer (CORM-2) on MCF-7 breast cancer cell cultures were evaluated, with particular regard to mechanisms affecting collagen biosynthesis. In our model, CORM-2 exerted dose-dependent cytotoxic and antiproliferative effects, i.e., attenuated cell viability, induced apoptosis and reduced autophagy. Collagen biosynthesis was significantly reduced, with signs of the involvement of nuclear factor kappa B, integrin β1, insulin-like growth factor 1 and proline metabolism as the probable underlying mechanism. No effects of CO-depleted CORM-2 were found, thereby demonstrating that CORM-2 activity is associated with carbon monoxide. Additionally, it was found that CORM-2 had no influence on control fibroblasts cultures. Our results confirm both the cytotoxic and collagen-related properties of CO-releasing molecule in a breast cancer cell culture, and therefore serve to encourage further research in a pre-clinical setting. To the best of our knowledge, this study is the first to attempt to relate the effects of CORM-2 on cell viability and collagen metabolism in a cancer cell culture.

Investigation of Curcumin-Loaded OA400 Nanoparticle's Effect on the Expression of E6 and E7 Human Papilloma-Virus Oncogenes and P53 and Rb Factors in HeLa Cell Line.

Curcumin, a compound derived from the root of the Curcuma longa, has been confirmed as an anticancer, chemoprotective, and gene/protein regulatory agent. Nanoformulation of curcumin has been developed to increase its targeting efficiency, solubility, controlled release, and physical and chemical stability. This study investigated the effect of new nano-type curcumin, oleic acid-derived dendrosome (OA400 nanoparticles), on the expression of E6 and E7 human papillomavirus oncogenes and P53 and Rb factors in the HeLa cell line. After preparing nano-curcumin by mixing OA400 nano-carrier and curcumin, its effect was considered on the human cervical cancer cell line (HeLa cell line RRID: CVCL_003) and normal fibroblast cells. MTT assay and flow cytometry were used to evaluate cell viability and apoptosis. Furthermore, real-time RT-PCR and western blot analyses assessed RNA and protein expression of E6, E7, P53, and Rb. Statistical analyses were performed by GraphPad Prism 7 software. The nanoformulation of curcumin could reduce the expression of E6 and E7 oncogenes and increase P53 and Rb tumor suppressors in HeLa cancerous cells at 15 μM concentration; however, it had no significant effect on the viability of normal fibroblast cells. On the other hand, curcumin altered the expression of these genes at a 50-μM concentration. Gene and protein expression analysis indicated the up-regulation of P53 and Rb factors and the down-regulation of E6 and E7 under the influence of nano-curcumin treatment more than curcumin. These data indicate the potential of curcumin-loaded OA400 nanoparticles to be considered as a treatment option in cervical cancer investigations.

“If We Changed Clothes, Sir, We Could Get Things Back to Normal”

“If We Changed Clothes, Sir, We Could Get Things Back to Normal”

The Ruthless Wealth of Health: Power Dynamics of Hospital Industry in Sulu Province

The people in Sulu usually go to hospitals and seek medical treatment when they are already in a severe condition that doctors can no longer cure and help. The qualitative method using focus group discussion and workshop conduct was employed, and the most appropriate sampling design is purposive. Four participants were invited and represented the actors from the regularity agent, supply side, demand side, and alternative substitute. Sixteen participants purposively drew and shared their opinions in the workshop. Findings show that the actors involved in the regulatory framework created by Republic Act of the Philippines and the policies and regulations were all done at the national level; the hospital director, administration, health provider, external suppliers together with the hospital and medical facilities, equipment, buildings, and services comprised the supply side in the hospital industry; the markets of the health services were the entire citizen of Sulu; alternative substitute like the traditional medicines and procedures like hilot were accepted by the Tausug. Lastly, all the interactions displayed by the different actors coming from the regulatory agent, supply side, demand side, and the alternative substitute described the nature and performance of the hospital industry in Sulu. Nonetheless, producing a climate of quality health care service.

Review on ecological interactions of the Cochliomyia hominivorax fly and assessment of the possible impacts of its eradication in Uruguay

Controlling a pest species raises questions about the harmful effects its eradication could cause in ecosystems. Currently, in Uruguay are being analyzed strategies to eradicate the New World Screwworm (NWS), Cochliomyia hominivorax (Diptera: Calliphoridae), an obligatory ectoparasite that causes myiasis in warm-blooded vertebrates, including humans. The loss of a species implies a risk of secondary extinctions and cascading effects that depend on the ecological function of the species and the capacity of the rest of the species with which it interacts to compensate for its loss. To assess the ecological impact of the NWS eradication, we analyzed its ecological redundancy, its effect as an indirect regulatory agent for other species, and its participation in critical ecosystem functions. We conclude that the NWS presents high functional redundancy in most ecological interactions. It does not play an essential role as a regulatory agent of other species and does not play an important role in critical ecosystem functions. Without ignoring the information gaps that certainly exist about the ecological interactions network of the NWS in Uruguay, we estimate that its eradication is unlikely to cause secondary extinctions or cascading effects in the networks it integrates. In order to timely detect possible impacts during the course of the program, it is recommended to monitor the ecosystems using indicators related to direct and indirect partners in the ecological interactions of the NWS.

Histidine phosphorylation in metalloprotein binding sites

Post-translational modifications (PTMs) are invaluable regulatory tools for the control of catalytic functionality, protein-protein interactions, and signaling pathways. Historically, the study of phosphorylation as a PTM has been focused on serine, threonine, and tyrosine residues. In contrast, the significance of mammalian histidine phosphorylation remains largely unexplored. This gap in knowledge regarding the molecular basis for histidine phosphorylation as a regulatory agent exists in part because of the relative instability of phosphorylated histidine as compared with phosphorylated serine, threonine and tyrosine. However, the unique metal binding abilities of histidine make it one of the most common metal coordinating ligands in nature, and it is interesting to consider how phosphorylation would change the metal coordinating ability of histidine, and consequently, the properties of the phosphorylated metalloprotein. In this review, we examine eleven metalloproteins that have been shown to undergo reversible histidine phosphorylation at or near their metal binding sites. These proteins are described with respect to their biological activity and structure, with a particular emphasis on how phosphohistidine may tune the primary coordination sphere and protein conformation. Furthermore, several common methods, challenges, and limitations of studying sensitive, high affinity metalloproteins are discussed.

A New Paradigm in the Relationship between Melatonin and Breast Cancer: Gut Microbiota Identified as a Potential Regulatory Agent.

Simple SummaryThe relationship between melatonin and breast cancer has been widely described. On the other hand, in recent years, an imbalance in the composition of the intestinal bacterial population has been linked as another possible trigger for this disease. Given that changes in the gut microbiota have been observed to stimulate the kinurenine pathway, reducing circulating melatonin levels, in this review, we summarize the relationship between circadian disruption and breast cancer, as well as the connection with dysbiosis as possible causing this pathology due to a series of changes that lead to an increase in circulating estrogen levels.In this review we summarize a possible connection between gut microbiota, melatonin production, and breast cancer. An imbalance in gut bacterial population composition (dysbiosis), or changes in the production of melatonin (circadian disruption) alters estrogen levels. On the one hand, this may be due to the bacterial composition of estrobolome, since bacteria with β-glucuronidase activity favour estrogens in a deconjugated state, which may ultimately lead to pathologies, including breast cancer. On the other hand, it has been shown that these changes in intestinal microbiota stimulate the kynurenine pathway, moving tryptophan away from the melatonergic pathway, thereby reducing circulating melatonin levels. Due to the fact that melatonin has antiestrogenic properties, it affects active and inactive estrogen levels. These changes increase the risk of developing breast cancer. Additionally, melatonin stimulates the differentiation of preadipocytes into adipocytes, which have low estrogen levels due to the fact that adipocytes do not express aromatase. Consequently, melatonin also reduces the risk of breast cancer. However, more studies are needed to determine the relationship between microbiota, melatonin, and breast cancer, in addition to clinical trials to confirm the sensitizing effects of melatonin to chemotherapy and radiotherapy, and its ability to ameliorate or prevent the side effects of these therapies.

Physiological effects of histamine on renal function in salt‐sensitive hypertension

Introduction . Histamine is a regulatory agent involved in the immune response, neurotransmission, and gastric acid secretion, and is produced and released from the mast cells and basophils. Elevated histamine levels and increased expression of histamine metabolizing enzymes have been reported in kidney diseases. The goal of this study is to provide insight into the physiological importance of the histamine-related pathways in salt-sensitive hypertension (SSH), a disease accompanied with inflammation-driven kidney damage. Methods . SSH was induced in Dahl Salt-Sensitive (DSS) rats by a 3-week long high salt diet challenge (HS, 4% NaCl); age-matched normal salt diet (NS, 0.4% NaCl) fed rats were used as a control group. To characterize the expression of histamine receptors, mast cells markers, and histamine metabolism-related enzymes, Western blot or IHC were performed on renal tissues collected from DSS rats maintained on HS or NS diets for 3 weeks. In order to test the effects of histamine receptor 2 (HR2) inhibition, he DSS rats were injected with a single daily i.p. dose of an HR2 blocker, ranitidine (RAN, 25mg/kg in saline) or saline (VEH), for 3 consecutive days before the switch to a HS diet, and at the end of the 21-day long HS challenge. Urine and water consumption were assessed in metabolic cages during hours 0-8 (acute), and 8-24 post-injections. At the end of the protocol, GFR was measured, and tissues were harvested. Results . Western blots revealed similar expression of the mast cell markers’ (FCER1A and tryptase) in NS and HS diet fed rats, however, we observed significantly lower histamine decarboxylase (HDC, p=0.002), and higher histamine N-methyltransferase (HNMT, p=0.035) levels in HS diet fed rats. Renal IHC revealed that expression of HR2 was downregulated, while HR3 and HR4 were upregulated in the collecting ducts of HS diet fed rats. In vivo experiments showed that RAN-administered rats on NS diet exhibited an acute (8-24 hr period) decrease in urine output and 24 h water intake on day 1 of injections (p=0.01). We observed trends for an increase in urinary electrolytes, and an overall increase in the excretion of osmolesin RAN vs VEH animals 24 hours post day 1 injection on the NS diet. Post HS challenge, electrolyte excretion, urine flow and water intake were similar between RAN and VEH animals. At the endpoint on HS, GFR between the groups was similar on day 3 post-injection. Conclusions . Differential expression of HRs, as well as changes in the enzymes responsible for histamine synthesis and metabolism between HS and NS fed rats, indicate a shift in the renal histaminergic tone during SSH development. Similar mast cell levels suggest an alternate, perhaps intrarenal, source of histamine. Our in vivo data show that inhibition of HR2 has effects on urine output and water consumption in SSH. Further research is required to discern the molecular pathways downstream of specific HRs, as well as the consequences of chronic administration of HR-specific pharmacology, in renal pathophysiology.

MECHANISMS FOR RISK ELIMINATION OF A COMPLIANCE TRAP IN THE BRAZILIAN TELECOMMUNICATIONS INDUSTRY

ABSTRACT Purpose: This study aims to analyze how the Brazilian National Communications Agency (Agência Nacional de Telecomunicações – Anatel) and cellular operators in Brazil used ceremonial and discursive practices to build enforcement and compliance actions, adopted during a period of crisis in the cellular sector industry in 2012 when the legitimacy of the respective regulatory model and the regulatory agent were challenged, shaping a compliance trap situation. Originality/value: The work fills a theoretical gap by associating the normative-cultural perspective of regulation associated with organizational institutionalism, based on the assertion that the relationship between regulator and regulated is interactive and not unidirectional, allowing that enforcement mechanisms represent political efforts, realigning the interests of the actors within their institutional environments. Design/methodology/approach: The case study research strategy with a qualitative approach is adopted, studying the 2012 crisis in the cellular sector industry, with the collection of data from documentary sources and semi-structured interviews with participants in the process. Findings: The results show that, in the compliance trap situation, symbolic criteria can appropriate the speeches, producing texts and practices in favor of legitimizing the enforcement mechanisms and the respective compliance responses in view of the audience. Therefore, the compliance trap risk on the regulatory agent is mitigated to the extent that ceremonial and discursive practices manifest themselves responsively and gain political and cultural support, reducing social pressure on the legitimacy of the regulation model.

Maintenance Schedule Optimization Applied to Large Hydroelectric Plants: Towards a Methodology Encompassing Regulatory Aspects

The maintenance schedule planning of hydro plant generating units is a subject of great interest to several agents in the energy industry. A correct approach for this problem can prevent the degradation of physical assets and minimize the probability of forced shutdowns of their equipment. In addition to these factors, due particularities of the Brazilian system, the operational strategies of its agents are also affected by the maintenance schedule of the generating units. This occurs due to the Availability Factor (AFA), which is directly influenced by the hours of maintenance performed at the plant and, in case of a performance below the stipulated in the concession contracts, it can lead to financial losses or administrative sanctions applied by the regulatory agent. With this motivation in mind, the present work proposes a methodology for Generator Maintenance Scheduling (GMS) of a hydroelectric plant, developing a mathematical model to determine the ideal moment to perform maintenance, considering operational restrictions and regulatory aspects of hydroelectric plants. The optimization methodology proposed for this problem is done through mixed-integer linear programming, where the integer variables consist of the operating state and start date of maintenance of each generating unit. In the end, to validate the proposed modeling, a case study is carried out for a real large plant in the Brazilian system.