Browsing by Author "Garcia, Cristian"

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    An Overview of Microgrids Challenges in the Mining Industry
    (2020) Gómez, Juan S.; Rodriguez, Jose; Garcia, Cristian; Tarisciotti, Luca; Flores-Bahamonde, Freddy; Pereda Torres, Javier Eduardo; Nuñez Retamal, Felipe Eduardo; Cipriano, Aldo; Salas, Juan Carlos
    The transition from fossil fuels to renewable energies as power sources in the heavy industries is one of the main climate change mitigation strategies. The carbon footprint in mining is related to its inherent extraction process, its high demand of electric power and water, and the use of diesel. However, considering its particular power requirements, the integration of microgrids throughout the whole control hierarchy of mining industry is an emergent topic. This paper provides an overview of the opportunities and challenges derived from the synergy between microgrids and the mining industry. Bidirectional and optimal power flow, as well as the integration of power quality have been identified as microgrid features that could potentially enhance mining processes. Recommendations pertaining to the technological transition and the improvement of energy issues in mining environments are also highlighted in this work.
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    Early Obesity: Risk Factor for Fatty Liver Disease
    (LIPPINCOTT WILLIAMS & WILKINS, 2020) Cuzmar, Valeriau; Alberti, Gigliola; Uauy, Ricardo; Pereira, Ana; Garcia, Cristian; De Barbieri, Florencia; Corvalan, Camila; Santos, Jose L.; Mericq, Veronica; Villarroel, Luis; Gana, Juan Cristobal
    Nonalcoholic fatty liver disease (NAFLD), defined as fat accumulation greater than 5% in hepatocytes, may progress to fibrosis or cirrhosis later in life. NAFLD prevalence in adolescents has increased significantly in direct relation with obesity prevalence. Fatty liver has become the most frequent indication for liver transplantation in adults. Objective: The aim of the study was to identify anthropometric variables during the first 10 years of life associated to the risk of developing NAFLD in adolescence. Methods: Longitudinal cohort study 'Growth and Obesity Chilean Cohort Study' (GOCS) consisting of 513 children born in 2002 to 2003, with yearly anthropometric data collected over a 10-year period. The presence of intrahepatic fat in the livers of subjects 14 to 16 years of age was determined using abdominal ultrasound. In addition, elastography was performed on all participants with ultrasound evidence of NAFLD. Results: 9.7% of the participants presented findings compatible with NAFLD. After 2 years of age, obesity significantly and progressively increased the probability of NAFLD occurrence in adolescence. Obesity at 5 years of age was associated with the highest OR for NAFLD, reaching values of 8.91 (95% CI 3.03-16.11). Among participants with NAFLD, those with altered liver elasticity (>= 7 kPa) had greater weight, BMIz-score, waist and hip circumference, and altered liver enzymes (P < 0.05). Conclusion: The risk of developing NAFLD in adolescence increases progressively with early obesity starting at age 2 years.
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    Osteoporosis in children with severe congenital neutropenia: Bone mineral density and treatment with bisphosphonates
    (LIPPINCOTT WILLIAMS & WILKINS, 2006) Borzutzky, Arturo; Reyes, Maria Loreto; Figueroa, Valeria; Garcia, Cristian; Cavieres, Mirta
    A high incidence of decreased bone mineral density (BMD) has been described in patients with severe congenital neutropenia (SCN). The objectives of the study are to describe changes in BMD in children with SCN treated with granulocyte colony-stimulating factor and evaluate the response to treatment with bisphosphonates in those two had osteoporosis. A prospective open-label study was performed evaluating BMD and metabolism in 9 Chilean patients with SCN, administrating bisphosphonates in those with osteoporosis. Follow-up ranged between 7 months and 3.5 years. Six out of 9 patients had reduced BMD on initial assessment: 3 had osteoporosis (z score < - 2) and 3, had osteopenia (z score < - 1). Four children presented vertebral fractures. Two presented osteopenia on follow-up without Clinical Symptoms. Five patients were treated with biphosphonates, increasing their BMD z Score (mean increase 1.2. range 0.27 to 2.62). z Score of hydroxyproline/ creatinine ratios, which was elevated in 4 patients with osteoperosis, decreases during treatment (mean decrease 2.18, range 1.56 to 2.53). Four patients remodeled and reexpanded fractured vertebrae during treatment. No side effects of bisphosphonate were seen on follow-up. Osteoporosis is an important comorbidity in SCN patients probably due to an increased bone resorption. Bisphosphonates seem to be an effective treatment for osteoporosis in these patients.