81 research outputs found
Analysis of Direct Torque Control using Space Vector Modulation for Three Phase Induction Motor
This paper presents the results of an investigation into the suitability of a Direct Torque Control of three phase Induction motor. It is considered as an alternative to the field oriented control (FOC) or vector control technique. They aim to control effectively the torque and flux. Direct Torque Control (DTC) uses an induction motor model to predict the voltage required to achieve a desired output torque. By using only current and voltage measurements, it is possible to estimate the instantaneous stator flux and output torque. An induction motor model is then used to predict the voltage required to drive the flux and torque to the demanded values within a fixed time period. This calculated voltage is then synthesized using Space Vector Modulation (SVM). Torque control of an induction machine based on DTC strategy has been developed and a comprehensive study is described. The performance of this control method has been demonstrated by simulations performed using a versatile simulation package, Matlab
Estudios mediáticos y fenómenos migratorios: una revisión sistemática de la literatura desde 2011 hasta 2021
Hacía falta un estado del arte que describiera los principales enfoques, resultados, métodos y teorías de la investigación académica en comunicación sobre el fenómeno migratorio durante la última década. Este análisis bibliométrico de 196 artículos en 37 revistas mayoritariamente escritas en español identificó las publicaciones principales en comunicación que han aportado al entendimiento de las migraciones. Los resultados de esta revisión de la literatura muestran que quienes trabajan en los medios atribuyen las fallas de su oficio a la falta de preparación y a la ausencia de manuales deontológicos; que la calidad de los productos mediáticos sobre la migración tiende a ser pobre; y que la literatura sobre las audiencias documenta los efectos de los medios y la percepción de los públicos receptores de migración. Esos hallazgos sugieren que existe un sesgo académico hacia los fenómenos migratorios latinoamericanos desde perspectivas interseccionales; que hacen falta acercamientos etnográficos a los procesos de creación mediática; que la investigación sobre los productos resulta repetitiva; y que, mientras los estudios sobre las audiencias europeas abundan, los de públicos migrantes escasean. La discusión invita a comprobar esas hipótesis y a incluir más voces latinoamericanas en la conversación global sobre las migraciones
Overexpression of TC-PTP in murine epidermis attenuates skin tumor formation
T-cell protein tyrosine phosphatase (TC-PTP), encoded by Ptpn2, has been shown to function as a tumor suppressor during skin carcinogenesis. In the current study, we generated a novel epidermal-specific TC-PTP-overexpressing (K5HA.Ptpn2) mouse model to show that TC-PTP contributes to the attenuation of chemically induced skin carcinogenesis through the synergistic regulation of STAT1, STAT3, STAT5, and PI3K/AKT signaling. We found overexpression of TC-PTP increased epidermal sensitivity to DMBA-induced apoptosis and it decreased TPA-mediated hyperproliferation, coinciding with reduced epidermal thickness. Inhibition of STAT1, STAT3, STAT5, or AKT reversed the effects of TC-PTP overexpression on epidermal survival and proliferation. Mice overexpressing TC-PTP in the epidermis developed significantly reduced numbers of tumors during skin carcinogenesis and presented a prolonged latency of tumor initiation. Examination of human papillomas and squamous cell carcinomas (SCCs) revealed that TC-PTP expression was significantly reduced and TC-PTP expression was inversely correlated with the increased grade of SCCs. Our findings demonstrate that TC-PTP is a potential therapeutic target for the prevention of human skin cancer given that it is a major negative regulator of oncogenic signaling
A Mathematical Model to Optimize the Neoadjuvant Chemotherapy Treatment Sequence for Triple-Negative Locally Advanced Breast Cancer
Background: Triple-negative locally advanced breast cancer is an aggressive tumor type. Currently, the standard sequence treatment is applied, administering anthracyclines first and then a taxane plus platinum. Clinical studies for all possible treatment combinations are not practical or affordable, but mathematical modeling of the active mitotic cell population is possible. Our study aims to show the regions with the tumor’s most substantial cellular population variation by utilizing all possible values of the parameters () that define the annihilatory drug capacity according to the proposed treatment.
Method: A piecewise linear mathematical model was used to analyze the cell population growth by applying four treatments: standard sequences of 21 days (SS21) and 14 days (SS14), administering anthracyclines first, followed by a taxane plus platinum, and inverted sequences of 21 days (IS21) and 14 days (IS14), administering a taxane plus platinum first then anthracyclines.
Results: The simulation showed a higher effect of IS14 over SS14 when the rate of drug resistance was larger in the cell population during DNA synthesis (G1 and S) compared to cells in mitosis (G2 and M). However, if the proportion of resistant cells in both populations was equivalent, then treatments did not differ.
Conclusions: When resistance is considerable, IS14 is more efficient than SS14, reducing the tumor population to a minimum
Reversible Keap1 inhibitors are preferential pharmacological tools to modulate cellular mitophagy
Mitophagy orchestrates the autophagic degradation of dysfunctional mitochondria preventing their pathological accumulation and contributing to cellular homeostasis. We previously identified a novel chemical tool (hereafter referred to as PMI), which drives mitochondria into autophagy without collapsing their membrane potential (ΔΨm). PMI is an inhibitor of the protein-protein interaction (PPI) between the transcription factor Nrf2 and its negative regulator, Keap1 and is able to up-regulate the expression of autophagy-associated proteins, including p62/SQSTM1. Here we show that PMI promotes mitochondrial respiration, leading to a superoxide-dependent activation of mitophagy. Structurally distinct Keap1-Nrf2 PPI inhibitors promote mitochondrial turnover, while covalent Keap1 modifiers, including sulforaphane (SFN) and dimethyl fumarate (DMF), are unable to induce a similar response. Additionally, we demonstrate that SFN reverses the effects of PMI in co-treated cells by reducing the accumulation of p62 in mitochondria and subsequently limiting their autophagic degradation. This study highlights the unique features of Keap1-Nrf2 PPI inhibitors as inducers of mitophagy and their potential as pharmacological agents for the treatment of pathological conditions characterized by impaired mitochondrial quality control
An Essential Mesenchymal Function for miR-143/145 in Intestinal Epithelial Regeneration
SummaryDownregulation of the miR-143/145 microRNA (miRNA) cluster has been repeatedly reported in colon cancer and other epithelial tumors. In addition, overexpression of these miRNAs inhibits tumorigenesis, leading to broad consensus that they function as cell-autonomous epithelial tumor suppressors. We generated mice with deletion of miR-143/145 to investigate the functions of these miRNAs in intestinal physiology and disease in vivo. Although intestinal development proceeded normally in the absence of these miRNAs, epithelial regeneration after injury was dramatically impaired. Surprisingly, we found that miR-143/145 are expressed and function exclusively within the mesenchymal compartment of intestine. Defective epithelial regeneration in miR-143/145-deficient mice resulted from the dysfunction of smooth muscle and myofibroblasts and was associated with derepression of the miR-143 target Igfbp5, which impaired IGF signaling after epithelial injury. These results provide important insights into the regulation of epithelial wound healing and argue against a cell-autonomous tumor suppressor role for miR-143/145 in colon cancer
Effectiveness of laughter therapy on anxiety and depression in hospitalized patients: a systematic review and meta-analysis
Objective: To verify the effectiveness of laughter therapy on anxiety and depression in hospitalized patients. Methods: A systematic review of experimental studies and quasi-experimental studies was carried out after being registered in the PROSPERO database (CRD42020138934). The search was performed in September 2022 in PubMed, Web of Science, Lilacs, Cochrane Library and Scopus. Inclusion criteria were: a) hospitalized patients who experienced anxiety or depression and who underwent at least one session of laughter therapy, b) studies with outcomes of laughter therapy on anxiety and depression. The studies were selected in two stages: by reading the titles and abstracts of the studies, and by reading the full papers that met the eligibility criteria. The risk of bias of the studies was assessed using the RoB 2 and ROBINS-I tools. The quality of the evidence synthesis was measured by GRADE. Results: 4,472 studies were found and 15 of them were included. Laughter therapy was shown to be effective in reducing anxiety and depression in both hospitalized children and adults. Ten were randomized controlled trials (nine of them were at high risk of bias) and five were quasi-experimental studies. Meta-analysis showed significant improvement in anxiety (mean difference = -10.55, 95% CI: -19.97, -1.14, p 0.03, I² = 84%) and depression (mean difference = -2.43, 95% CI: -3.63, -1.24, p <0.0001, I² =0%). Conclusion: According to the findings of this study, it was verified that laughter therapy seems to be more effective than standard care for reducing anxiety and depression in hospitalized patients. However, further studies with low risk of bias are required
Serum carotenoids and Pediatric Metabolic Index predict insulin sensitivity in Mexican American children
High concentrations of carotenoids are protective against cardiometabolic risk traits (CMTs) in adults and children. We recently showed in non-diabetic Mexican American (MA) children that serum α-carotene and β-carotene are inversely correlated with obesity measures and triglycerides and positively with HDL cholesterol and that they were under strong genetic influences. Additionally, we previously described a Pediatric Metabolic Index (PMI) that helps in the identification of children who are at risk for cardiometabolic diseases. Here, we quantified serum lycopene and β-cryptoxanthin concentrations in approximately 580 children from MA families using an ultraperformance liquid chromatography-photodiode array and determined their heritabilities and correlations with CMTs. Using response surface methodology (RSM), we determined two-way interactions of carotenoids and PMI on Matsuda insulin sensitivity index (ISI). The concentrations of lycopene and β-cryptoxanthin were highly heritable [h2 = 0.98, P = 7 × 10-18 and h2 = 0.58, P = 1 × 10-7]. We found significant (P ≤ 0.05) negative phenotypic correlations between β-cryptoxanthin and five CMTs: body mass index (- 0.22), waist circumference (- 0.25), triglycerides (- 0.18), fat mass (- 0.23), fasting glucose (- 0.09), and positive correlations with HDL cholesterol (0.29). In contrast, lycopene only showed a significant negative correlation with fasting glucose (- 0.08) and a positive correlation with HDL cholesterol (0.18). Importantly, we found that common genetic influences significantly contributed to the observed phenotypic correlations. RSM showed that increased serum concentrations of α- and β-carotenoids rather than that of β-cryptoxanthin or lycopene had maximal effects on ISI. In summary, our findings suggest that the serum carotenoids are under strong additive genetic influences and may have differential effects on susceptibility to CMTs in children
Serum Carotenoids and Pediatric Metabolic Index Predict Insulin Sensitivity in Mexican American Children
High concentrations of carotenoids are protective against cardiometabolic risk traits (CMTs) in adults and children. We recently showed in non-diabetic Mexican American (MA) children that serum α-carotene and β-carotene are inversely correlated with obesity measures and triglycerides and positively with HDL cholesterol and that they were under strong genetic influences. Additionally, we previously described a Pediatric Metabolic Index (PMI) that helps in the identification of children who are at risk for cardiometabolic diseases. Here, we quantified serum lycopene and β-cryptoxanthin concentrations in approximately 580 children from MA families using an ultraperformance liquid chromatography-photodiode array and determined their heritabilities and correlations with CMTs. Using response surface methodology (RSM), we determined two-way interactions of carotenoids and PMI on Matsuda insulin sensitivity index (ISI). The concentrations of lycopene and β-cryptoxanthin were highly heritable [h2 = 0.98, P = 7 × 10–18 and h2 = 0.58, P = 1 × 10–7]. We found significant (P ≤ 0.05) negative phenotypic correlations between β-cryptoxanthin and five CMTs: body mass index (− 0.22), waist circumference (− 0.25), triglycerides (− 0.18), fat mass (− 0.23), fasting glucose (− 0.09), and positive correlations with HDL cholesterol (0.29). In contrast, lycopene only showed a significant negative correlation with fasting glucose (− 0.08) and a positive correlation with HDL cholesterol (0.18). Importantly, we found that common genetic influences significantly contributed to the observed phenotypic correlations. RSM showed that increased serum concentrations of α- and β-carotenoids rather than that of β-cryptoxanthin or lycopene had maximal effects on ISI. In summary, our findings suggest that the serum carotenoids are under strong additive genetic influences and may have differential effects on susceptibility to CMTs in children
Guidelines on experimental methods to assess mitochondrial dysfunction in cellular models of neurodegenerative diseases
Neurodegenerative diseases are a spectrum of chronic, debilitating disorders characterised by the progressive degeneration and death of neurons. Mitochondrial dysfunction has been implicated in most neurodegenerative diseases, but in many instances it is unclear whether such dysfunction is a cause or an effect of the underlying pathology, and whether it represents a viable therapeutic target. It is therefore imperative to utilise and optimise cellular models and experimental techniques appropriate to determine the contribution of mitochondrial dysfunction to neurodegenerative disease phenotypes. In this consensus article, we collate details on and discuss pitfalls of existing experimental approaches to assess mitochondrial function in in vitro cellular models of neurodegenerative diseases, including specific protocols for the measurement of oxygen consumption rate in primary neuron cultures, and single-neuron, time-lapse fluorescence imaging of the mitochondrial membrane potential and mitochondrial NAD(P)H. As part of the Cellular Bioenergetics of Neurodegenerative Diseases (CeBioND) consortium ( www.cebiond.org ), we are performing cross-disease analyses to identify common and distinct molecular mechanisms involved in mitochondrial bioenergetic dysfunction in cellular models of Alzheimer's, Parkinson's, and Huntington's diseases. Here we provide detailed guidelines and protocols as standardised across the five collaborating laboratories of the CeBioND consortium, with additional contributions from other experts in the field
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