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In the present work, both direct and inverse problems are considered for a Fisher-type fractional diffusion equation, which is proposed to describe the phenomenon of cell migration. For the direct problem, a solution is given via the Fourier method and the Laplace transform. On the other hand, we solved the inverse problem from a Bayesian statistical framework using a set of data that are the result of a cell migration experiment on a wound closure assay. We estimated the parameters of the mathematical model via Markov Chain Monte Carlo methods.

Abstract Leptin is an adipokine secreted by adipose tissue, which promotes tumor progression by activating canonical signaling pathways such as MAPK/ERK. Recent studies have shown that leptin induces autophagy, and this process is involved in leptin-induced characteristics of malignancy. Autophagy is an intracellular degradation process associated with different hallmarks of cancer, such as cell survival, migration, and metabolic reprogramming. However, its relationship with metabolic reprogramming has not been clearly described. The purpose of this study was to determine the role of leptin-induced autophagy in cancer cell metabolism and its association with cellular proliferation and migration in breast cancer cells. We used ER+/PR+ and triple-negative breast cancer cell lines treated with leptin, autophagy inhibition, or mitochondrial metabolism inhibitors. Our results show that leptin induces autophagy, increases proliferation, mitochondrial ATP production and mitochondrial function in ER+/PR+ cells. Importantly, autophagy was required to maintain metabolic changes and cell proliferation driven by leptin. In triple-negative cells, leptin did not induce autophagy or cell proliferation but increased glycolytic and mitochondrial ATP production, mitochondrial function, and cell migration. In triple negative cells, autophagy was required to support metabolic changes and cell migration, and autophagy inhibition decreased cellular migration similar to mitochondrial inhibitors. In conclusion, leptin-induced autophagy supports mitochondrial metabolism in breast cancer cells as well as glycolysis in triple negative cells. Importantly, leptin-induced mitochondrial metabolism promoted cancer cell migration.

Breast cancer is the most common invasive neoplasm and the leading cause of cancer death in women worldwide. The main cause of mortality in cancer patients is invasion and metastasis, where the epithelial-mesenchymal transition (EMT) is a crucial player in these processes. Pharmacological therapy has plants as its primary source, including isoflavonoids. Brazilin is an isoflavonoid isolated from Haematoxilum brasiletto that has shown antiproliferative activity in several cancer cell lines. In this study, we evaluated the effect of Brazilin on canonical markers of EMT such as E-cadherin, vimentin, Twist, and matrix metalloproteases (MMPs). By Western blot, we evaluated E-cadherin, vimentin, and Twist expression and the subcellular localization by immunofluorescence. Using gelatin zymography, we determined the levels of secretion of MMPs. We used Transwell chambers coated with matrigel to determine the in vitro invasion of breast cancer cells treated with Brazilin. Interestingly, our results show that Brazilin increases 50% in E-cadherin expression and decreases 50% in vimentin and Twist expression, MMPs, and cell invasion in triple-negative breast cancer (TNBC) MDA-MB-231 and to a lesser extend in MCF7 ER+ breast cancer cells. Together, these findings position Brazilin as a new molecule with great potential for use as complementary or alternative treatment in breast cancer therapy in the future.

The present work presents an investigation of the effects of xanthan gum (XG) and soy lecithin (SL) on the physicochemical stability, fatty acid profile (FAP), and antioxidant capacity (AC) of macadamia nut-based beverages with thermal treatment (TT), as well as physicochemical changes during storage and sensorial acceptability. An extreme vertices mixture design was used, varying the macadamia nut, SL, and XG. The results show that adding XG and SL decreased the Sauter (D[3,2]) and Brouckere (D[4,3]) diameters of particles in macadamia beverages and increased the zeta potential (ZP), which represents greater stability. After applying TT in beverages, D[3,2], D[4,3], and ZP increased. After processing and TT, the FAP and fat nutritional indices changed due to reducing SFA and PUFA and increasing MUFA relative to macadamia nut. No significant difference (p ≥ 0.05) was observed in the FAP of beverages with and without TT. The AC determined by DPPH and ABTS decreased in most beverages upon TT application. During storage for two months, the beverage particle size increased, there was a decrease in brightness, and no significant difference (p ≥ 0.05) was observed in ZP. Sensory analysis showed that the most stable beverage was not the most acceptable due to its viscosity.

Plaque Psoriasis (PP) and periodontitis are inflammatory disorders with a bidirectional association. They both have a qualitatively similar immune-modulatory cascade, cytokine profile, and a recently described dysbiosis. Different oral bacterial species compositions in the periodontal pocket might play a role in the development of PP. To describe the subgingival microbiota of the Mexican population with PP and the periodontal conditions. Subjects were divided into two groups: periodontal health (PH) (PH-non-PP, PH-PP) and periodontitis (PD) (P-non-PP, PD-PP). Following clinical examination, the patients were classified into three groups according to the degree of psoriasis as measured by the Psoriasis Area Severity Index (PASI) and the periodontal status according to the parameters of the American Academy of Periodontology (AAP). Subgingival microbiota samples of each patient were used to determine 40 species of periodontal bacteria by checkerboard DNA-DNA hybridization. IL-2 and IL-6 were measured by ELISA. Of the forty-eight patients with PP, 21 patients had PH and 27 patients had PD. PD-PP group has a significant increase in the percentage of plaque, gingival redness, pocket probing depth, and clinical attachment loss (P 5 related to periodontitis with the predominance of Actinomyces periodontal, irrespective of their periodontal condition. Finally, the severity of psoriasis could be unbalanced in subgingival microbiota and increase the risk to develop periodontitis.

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype due to its greater invasive capacity and non-response to hormone therapy. Several species of the Ficus genus have been used as an alternative to traditional medicine against malignant diseases. Previously, leaf extracts from Ficus crocata (Miq.) Mart. ex Miq. (F. crocata) showed antiproliferative activity in vitro against breast and cervical tumor cells without having a cytotoxic effect on non-tumor cell lines. The purpose of the study was to evaluate the effect of hexane (Hex-EFc), dichloromethane (Dic-EFc), and acetone (Ace-EFc) extracts from F. crocata on the proliferative and invasive capacity of breast cancer cells MCF-7 and MDA-MB-231. Materials and methods: The phytochemical profile was carried out by gas chromatography-mass spectrometry (GC-MS). Cell proliferation, migration, and invasion were determined by MTT, wound closure, and transwell assays, respectively. MMPs activity was analyzed using gelatin zymography, and fluorescence microscopy was used to visualize F-actin distribution. Results: Hex-EFc, Dic-EFc, and Ace-EFc showed cytotoxic activity on MDA-MB-231 tumor cells and, to a lesser extent, on MCF-7 cells, without presenting cytotoxicity at the same concentrations in MCF-10A non-tumor cells. Dic-EFc and Ace-EFc (5–10 μg/mL) reduced the migration capacity of MCF-7 and MDA-MB-231 cells. Interestingly, exposure to Dic-EFc and Ace-EFc (5–10 μg/mL) inhibited the invasive ability of MDA-MB-231 cells, reducing the secretion and activity of MMP-2 and MMP-9, as well as the F-actin distribution. Conclusions: Dic-EFc and Ace-EFc at low concentrations decreased breast cancer cell proliferation and invasiveness, mainly of MDA-MB-231 cells. The above supports the potential use of compounds from leaf extracts of F. crocata in neoadjuvant therapy to reduce the progression of breast cancer tumors, mainly triple-negative tumors.

Background and Objectives: REST (RE1-silencing transcription factor) diminution is associated with transcriptional relaxation, neuropeptide overexpression, and phenotype redefinition in neuroendocrine cancers, but this effect has barely been studied in cervical cancer (CC). We previously reported reduced expressions of REST in samples with premalignant lesions and CC; however, the transcriptional consequences for neural genes associated with reduced REST expression in CC are unknown. Therefore, the objective of this work was to evaluate the expression of neuronal genes in cancerous cells with reduced expression levels of REST. Materials and Methods: Here, we monitored levels of REST by immunostaining along the premalignant lesions and in invasive cervical squamous cell carcinoma (SCC) and endocervical adenocarcinoma (ADC) in tissue samples from female patients from southern Mexico and the derivative cell lines SiHa and HeLa, respectively. Next, we selected REST target genes in silico and explored the effect of REST silencing by RT-PCR in siRNA-treated HeLa cells. Results: The results show a REST diminution in premalignant lesions, SCC, ADC, and cancerous cell lines. Further REST silencing in HeLa cells altered the expression of genes containing the RE1 (Restrictive Element 1) sequence, including CgA (chromogranin A), CHRNβ2 (cholinergic receptor nicotinic β 2 subunit), BDNF (brain-derived neurotrophic factor), CRF (corticotropin-releasing factor), and RASSF1A (Ras association domain family 1). Conclusions: This work provides preliminary evidence of the role of REST loss in the transcriptional regulation of its target genes in HeLa cells, which could have positive implications for the search for new biomarkers of cervical cancer.

Abstract Malignant transformation and progression in cancer is associated with the altered expression of multiple miRNAs, which are considered as post-transcriptional regulators of genes participating in various cellular processes. Although, it has been proposed that miR-23b-3p acts as a tumor suppressor in cervical cancer (CC), not all the pathways through which it alters the cellular processes have been described. The present study examines whether miR-23b-3p directly represses the c-Met expression and that consequently modifies the proliferation, migration and invasion of C33A and CaSki cells. c-Met has five microRNA response elements (MREs) for miR-23b-3p in the 3′-UTR region. The ectopic overexpression of miR-23b-3p significantly reduces c-Met expression in C33A and CaSki cells. The overexpression of miR-23b-3p reduces proliferation, migration and invasion of CaSki cells and the proliferation and invasion in C33A cells. In CaSki cells, the activation of Gab1 and Fak, downstream of c-Met, is reduced in response to the overexpression of miR-23b-3p. Together, the results in the present study indicate that miR-23b-3p is a tumor suppressor that modulates the progression of CC via post-transcriptional regulation of the c-Met oncogene.

Breast cancer is the most common invasive neoplasia, and the second leading cause of the cancer deaths in women worldwide. Mammary tumorigenesis is severely linked to obesity, one potential connection is leptin. Leptin is a hormone secreted by adipocytes, which contributes to the progression of breast cancer. Cell migration, metalloproteases secretion, and invasion are cellular processes associated with various stages of metastasis. These processes are regulated by the kinases FAK and Src. In this study, we utilized the breast cancer cell lines MCF7 and MDA-MB-231 to determine the effect of leptin on FAK and Src kinases activation, cell migration, metalloprotease secretion, and invasion. We found that leptin activates FAK and Src and induces the localization of FAK to the focal adhesions. Interestingly, leptin promotes the activation of FAK through a Src- and STAT3-dependent canonical pathway. Specific inhibitors of FAK, Src and STAT3 sho wed that the effect exerted by leptin in cell migration in breast cancer cells is dependent on these proteins. Moreover, we established that leptin promotes the secretion of the extracellular matrix remodelers, MMP-2 and MMP-9 and invasion in a FAK and Src-dependent manner. Our findings strongly suggest that leptin promotes the development of a more aggressive invasive phenotype in mammary cancer cells.

In the present work, the total phenolic content (TPC), total flavonoids content (TFC), antioxidant activity, and phenolic profile from pulp (PU) and peel (PE) extracts obtained from the ciricote (Cordia dodecandra A. DC.) fruit by ultrasound-assisted extraction (UAE) in immature (IM), semimature (SM), and mature (MM) stages were investigated. The effect of the diameter of the ultrasonic probe in the IM stage was also evaluated. The TPC and antioxidant activity in IM fruit extracts by UAE increased up to 11.01 and 23.82 times, respectively, compared to the maceration method. The main phenolic compounds in the PE of IM fruit identified by UPLC-DAD-ESI-MS/MS were quantified as caffeic acid, rutin, and rosmarinic acid, distributed as 45.82, 41.45, and 12.72%, respectively. The PE extracts of IM fruit obtained with the 3 mm diameter probe had 1.27, 2.44, and 1.37 times the TPC (19.93 ± 0.28 mg GAE (Gallic equivalents) g−1 dw), TFC (34.85 ± 4.99 mg RE (Rutin equivalents) g−1 dw), and antioxidant activity (122.09 ± 17.09 µTE (Trolox equivalents) g−1 (DPPH)), respectively, compared to those obtained with a 13 mm diameter probe. The results obtained suggest the use of the ciricote native fruit as a source of bioactive compounds, directly as fresh fruit or processed, thus helping to increase its production and consumption.

Excess body weight and obesity have become significant risk factors for cancer development. During obesity, adipose tissue alters its biological function, deregulating the secretion of bioactive factors such as hormones, cytokines, and adipokines that promote an inflammatory microenvironment conducive to carcinogenesis and tumor progression. Adipokines regulate tumor processes such as apoptosis, proliferation, migration, angiogenesis, and invasion. Additionally, it has been found that they can modulate autophagy, a process implicated in tumor suppression in healthy tissue and cancer progression in established tumors. Since the tumor-promoting role of autophagy has been well described, the process has been suggested as a therapeutic target in cancer. However, the effects of targeting autophagy might depend on the tumor type and microenvironmental conditions, where circulating adipokines could influence the role of autophagy in cancer. Here, we review recent evidence related to the role of adipokines in cancer cell autophagy in an effort to understand the tumor response in the context of obesity under the assumption of an autophagy-targeting treatment.

Autophagy is an intracellular recycling process active in eukaryotic cells that involves the formation of an autophagosome which delivers cytoplasmic components to the lysosome for degradation. This process occurs at low rates under basal conditions, but it can be induced by diverse types of stress such as starvation, hypoxia, metabolic disorders or in response to hormones, including leptin. Leptin is considered a pro-tumorigenic protein whose circulating levels have been related to bad prognosis in obese breast cancer patients. It has been recently demonstrated that leptin can induce autophagy in cancer cell lines from different tissues, suggesting that autophagy could modulate the pro-tumorigenic effects associated with leptin. In this study, the role of autophagy in leptin-induced proliferation, migration, apoptosis and ERK phosphorylation in breast cancer cell lines was evaluated. Although leptin differentially induced autophagy in the breast cancer cell lines tested, autophagy inhibition reduced leptin-induced cell proliferation in MCF7 cells and decreased cell migration, ERK activation, and impaired morphological changes in both cell lines. Our data demonstrates an important role for basal autophagy or leptin-induced autophagy in leptin-induced migration and ERK phosphorylation in breast cancer cell lines, suggesting a potential use for the inhibition of autophagy in breast cancer associated with obesity.

Abstract Background Cervical cancer (CC) is the fourth cause of mortality by neoplasia in women worldwide. The use of immunomarkers is an alternative tool to complement currently used algorithms for detection of cancer, and to improve selection of therapeutic schemes. Aberrant expression of Ezrin and E-cadherin play an important role in tumor invasion. In this study we analyzed Ezrin and E-cadherin expression in liquid-based cervical cytology samples, and evaluated their potential use as prognostic immunomarkers. Methods Immunocytochemical staining of Ezrin and E-cadherin was performed in cervical samples of 125 patients. The cytological or histological diagnostic was performed by Papanicolaou staining or H&E staining, respectively. HPV genotyping was determined using INNO-LIPA Genotyping Extra kit and the HPV physical status by in situ hybridization. Ezrin expression in HaCaT, HeLa and SiHa cell lines was determined by immunocytochemistry, immunofluorescence and Western blot. Results High Ezrin expression was observed in cervical cancer samples (70%), samples with multiple infection by HR-HPV (43%), and samples with integrated viral genome (47%). High Ezrin expression was associated with degree of SIL, viral genotype and physical status. In contrast, low E-cadherin expression was found in cervical cancer samples (95%), samples with multiple infection by HR-HPV/LR-HPV (87%) and integrated viral genome (72%). Low E-cadherin expression was associated with degree of SIL and viral genotype. Interestingly, Ezrin nuclear staining was associated with degree of SIL and viral genotype. High Ezrin expression, high percent of nuclear Ezrin and low E-cadherin expression behaved as risk factors for progression to HSIL and cervical cancer. Conclusions Ezrin and E-cadherin expression profile in cervical cytology samples could be a potential prognostic marker, useful for identifying cervical lesions with a high-risk of progression to cervical cancer.

Pertussis-like syndrome and whooping cough-like illness are the terms used to refer to the indistinguishable signs and symptoms of whooping cough in the absence of laboratory tests to confirm the presence of the bacteria that causes it. Although there are no reported cases in Cuba, it is important to keep paying attention to the most representative symptoms of this disease, since there has recently been a resurgence of whooping cough in the world. Therefore, it is relevant to present the case of a patient with a two-week history of upper respiratory symptoms and dry cough. These symptoms intensified, so she attended the emergency service of her health area.

Epithelial−mesenchymal transition (EMT) is a reversible cellular process, characterized by changes in gene expression and activation of proteins, favoring the trans-differentiation of the epithelial phenotype to a mesenchymal phenotype. This process increases cell migration and invasion of tumor cells, progression of the cell cycle, and resistance to apoptosis and chemotherapy, all of which support tumor progression. One of the signaling pathways involved in tumor progression is the MAPK pathway. Within this family, the ERK subfamily of proteins is known for its contributions to EMT. The ERK subfamily is divided into typical (ERK 1/2/5), and atypical (ERK 3/4/7/8) members. These kinases are overexpressed and hyperactive in various types of cancer. They regulate diverse cellular processes such as proliferation, migration, metastasis, resistance to chemotherapy, and EMT. In this context, in vitro and in vivo assays, as well as studies in human patients, have shown that ERK favors the expression, function, and subcellular relocalization of various proteins that regulate EMT, thus promoting tumor progression. In this review, we discuss the mechanistic roles of the ERK subfamily members in EMT and tumor progression in diverse biological systems.

Fundamento: el estudio de la violencia desde la perspectiva de género aporta una nueva lectura en el comportamiento de las mujeres que rompen o no con relaciones abusivas. Objetivo: caracterizar desde la perspectiva de género a las mujeres que han sido maltratadas por su pareja. Métodos: estudio descriptivo, realizado en el policlínico Área V del municipio Cienfuegos en el año 2010. Fueron estudiadas 21 mujeres que denunciaron el delito y 42 maltratadas que no lo denunciaron, pertenecientes al mismo consultorio. Las variables analizadas fueron: edad, nivel educacional, color de la piel, tipología de la violencia, móvil para denunciar o no, tipificación, estereotipo, identidad y roles de género, tiempo de la relación violenta, percepción del apoyo de los grupos mediatizadores y del equipo básico de salud, reacciones emocionales y trastornos psicofisiológicos. Resultados: al analizar las variables para cada grupo, no se encontraron diferencias significativas en cuanto a las características identificativas, tiempo de la relación violenta y percepción del apoyo del equipo básico de salud. Sí fueron significativas estadísticamente las diferencias halladas con respecto al tipo de violencia, identidad genérica, patrones estereotipados, desempeño de roles, reacciones emocionales negativas, y percepción de los grupos mediatizadores. Conclusiones: el maltrato conyugal repercute de manera negativa en la salud de las mujeres que sufren de violencia íntima, fundamentalmente en las que no denuncian el delito.

Background: Low-grade squamous intraepithelial lesions (LSIL) are the earliest lesions of the uterine cervix, the persistence and integration of high-risk human papillomavirus (HR-HPV) as type 16, which promotes the development of more aggressive lesions. Aim: To select more aggressive lesions with tendency to progress to invasive cervical cancer. Materials and Methods: A total of 75 cytological specimens in liquid base (Liqui-PREP) were analyzed: 25 specimens were with no signs of SIL (NSIL) and without HPV; 25 NSIL with HPV-16, and 25 with both LSIL and HPV-16. The expression of Ki-67, telomerase, and viral E6 was evaluated by immunocytochemistry; and the detection of viral DNA was done by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLPs) for genotyping or sequencing of HPV-16. The physical state of HPV-16 was evaluated by in situ hybridization with amplification with tyramide. Results: Of the total group, 58.6% had LSIL associated with persistence and of these 59.3% was associated with integrated state of HPV as intense expression of E6, Ki-67 (P = 0.013, P = 0.055) has except for the expression of telomerase present a non-significant association (P

La educación en el trabajo es la forma fundamental de organización del proceso docente educativo en los años de estudio superiores de las carreras de la Educación Médica Superior. Durante este proceso se adoptan distintas formas organizativas docentes, y es la interconsulta docente-asistencial una de ellas. Se realizó una revisión sobre la metodología de esta forma organizativa, en la que se hace énfasis en las características, objetivos, etapas y funciones del docente. La interconsulta docente-asistencial debe ser preparada, organizada y dirigida por el profesor interconsultante. Se realiza principalmente en el consultorio médico de la familia. Consta de varias etapas: organización exhaustiva de la actividad, etapa previa de preparación por parte del Equipo Básico de Salud, presentación del paciente, análisis colectivo (trabajo docente en cascada) y conclusiones. Esta actividad desarrollada en la Atención Primaria de Salud con estas características, ha de propiciar la formación y desarrollo de habilidades y conocimientos necesarios para el desempeño de los profesionales. La interconsulta docente-asistencial se adentra en la enseñanza y aplicación del método clínico durante el proceso formativo del personal médico, en el que el profesor desempeña un papel importante al demostrar la importancia de este, al fomentar los principios éticos, de forma tal que forme parte de la práctica profesional y de su futuro desempeño.

Introduction: Diabetes mellitus is a significant health problem worldwide, since it is one of the most frequent non-transmissible diseases as for the variety and intensity of complications associated with it. Objective: To assess some physical, psychic and social aspects related with life quality of these patients. Methods: A descriptive, cross-sectional study was developed in the in the Centre for Care and Education of Diabetic Patients, between 2006 and 2007. The universe was formed by 148 diabetic patients (type II) that received ambulatory assistance in that institution. Variables: age, sex, years suffering from that disease, associated diseases and nutritional assessment according to the body mass index. Results: There was grater incidence of females, most of the patients were between 40 and 59 years; it was significant the association of diabetes with hypertension, mainly in overweight patients. Life quality was poorer with more years of diseases evolution, the obese patients and those with peripheral vascular disease. Conclusion: Even when life quality of diabetic patients is not generally deteriorated, there is a negative disposition towards the disease.

En el artículo se realiza un análisis de dos sensores que se aplican en energías renovables (eólica y solar),obteniéndose una ley de control óptima. Para las fuentes energéticas elegidas se proponen técnicas de altafrecuencia de conmutación y eficiencia. Para la validación de los resultados se emplean técnicas desimulación digital In this article we make an analysis of two sensors applied in renewable energies (wind and solar),obtaining an ideal law of control. For the chosen energetic sources there appear technologies of highfrequency of commutation and of high efficiency. Technologies of digital simulation validate the results.

En este artículo, se prueba de manera virtual, un controlador basado en lógica difusa para un sistema híbrido degeneración de energía. La simulación digital emplea como herramienta el Labview, obteniéndose resultadosgráficos descriptivos de la acción del controlador, así como la interfaz gráfica representativa del comportamientodel sistema. In this article is tested a virtual controller using fuzzy logic for a hybrid system of power generation.LABVIEW is used as a digital simulation tool obtaining descriptive graphical results of the action of the driveras well as a graphical interface of the behavior of the system.

Se presenta el caso de una paciente femenina de 32 años de edad que consulta al ginecólogo por presentar dolor mantenido de mediana intensidad en hipogastrio y crisis de sepsis urinaria repetida. Se comprobó la presencia de un cuerpo extraño (dispositivo intrauterino) en la vejiga, mediante la realización de endoscopia y por esta vía se logró extraer. Actualmente la paciente está asintomáticaA 32 year-old female patient who visits the gynecologist due to a mantained pain of moderate intensity in the hypogastrium and repeated crises of urinary sepsis is presented. The presence of a foreign body (intrauterine device) in the urinary bladder is proved by endoscopy, which is also used to extract it. At present, the patient is asymptomatic

We present a linear time-varying Luenberger observer (LTVLO) using compartmental models to estimate the unmeasurable states in patients with type 1 diabetes. The proposed LTVLO is based on the linearization in an operation point of the virtual patient (VP), where a linear time-varying system is obtained. LTVLO gains are obtained by the selection of the asymptotic eigenvalues where the observability matrix is assured. The estimation of the unmeasurable variables is done using Ackermann's methodology. The Lyapunov approach is used to prove the stability of the time-varying proposal. In order to evaluate the proposed methodology, we designed three experiments: 1) VP obtained with Bergman's minimal model; 2) VP obtained with Hovorka's model; and 3) real patient data set. For both experiments 1) and 2), it is applied a meal plan to the VP, where the dynamic response of each state model is compared with the response of each variable of the time-varying observer. Once the observer is obtained in experiment 2), the proposal is applied to experiment 3) with data extracted from real patients, and the unmeasurable state space variables are obtained with the LTVLO. LTVLO methodology has the feature of being updated each time instant to estimate the states under a known structure. The results are obtained using simulation with MATLAB and Simulink. The LTVLO estimates the unmeasurable states from in silico patients with high accuracy by means of the update of Luenberger gains at each iteration. The accuracy of the estimated state space variables is validated through thefit parameter.

On this paper, a robust velocity controller applied to a three-phase squirrel-cage induction motor under variable load conditions is designed. The induction motor drives an induction generator representing the load which freely delivers the generated power to the utility grid. The closed-loop scheme is designed at αβ coordinate frame and is based on the linearization block control technique in combination with the super-twisting algorithm. The controlled output variables are the angular mechanical velocity and the square modulus of rotor flux linkages. The motor reference velocity is set up by a pulse train above the synchronous velocity and, consequently, the impelled induction machine operates in generator mode; meanwhile, the reference of rotor flux square modulus varies according to load condition of the induction motor. In order to estimate the non-measurable variables, both a rotor flux linkages observer and a load torque observer are designed. For the first one, a non-linear state observer using first order sliding modes is applied at αβ coordinate frame and, for the second one, a Luenberger reduced asymptotic observer is used. The validation of the robustness for the proposed velocity controller is performed in a real-time experiment using a work-bench.