Browsing by Author "Garcia, Cristian"

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    Infantile/Capillary Hemangioma of the Uterine Corpus: A Rare Cause of Abnormal Genital Bleeding
    (2022) Ralph, Constanza; Cuello, Mauricio A.; Merino, Paulina M.; De Barbieri, Florencia M.; Astudillo, Katya; Huete, Alvaro; Garcia, Cristian; Pomes, Cristian
    Background: Infantile hemangiomas are vascular anomalies. However, they rarely cause genital bleeding. Here, we present the case of a young female with an endocavitary hemangioma who presented with abnormal uterine bleeding (AUB).Case: The patient was an 8-year-old female with genital bleeding. Transabdominal pelvic ultrasound showed a 20-mm highly vascularized focal intrauterine endocavitary lesion. Vascular computerized tomography excluded vascular anomalies. Magnetic resonance imaging sug-gested a hemangioma. Minimally invasive open surgery was performed to remove the lesion. Subsequent pathology analyses confirmed an infantile/capillary hemangioma. Conclusions: Infantile hemangiomas are vascular anomalies that should be considered potential causes of AUB in early puberty. The study of these cases should include pelvic ultrasound and vascular magnetic resonance imaging. Experienced surgeons can successfully accomplish fertility-sparing surgical procedures. Summary: We describe an unusual case of peripubertal AUB caused by an endocavitary capillary hemangioma. Management included fertility-sparing surgery and the complete resolution of symptoms.
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    Model Predictive Control in Multilevel Inverters Part II: Renewable Energies and Grid Applications
    (2024) Norambuena, Margarita; Mora, Andres; Garcia, Cristian; Rodriguez, Jose; Aly, Mokhtar; Carnielutti, Fernanda; Pereda, Javier; Castillo, Cristian; Zhang, Zhenbin; Yaramasu, Venkata; Tarisciotti, Luca; Yin, Yafei
    This article presents the use of model predictive control (MPC) in multilevel inverters for some applications, such as, first, wind generation and, second, photovoltaics, showing that the particular restrictions of each of them can be very easily included in the control algorithm, which is an important advantage of this technique. Another application is in modular multilevel cascaded converters, where it is demonstrated that MPC can operate with very few calculations and fixed switching frequency. The second part of this article is dedicated to comparing MPC with linear control and pulsewidth modulation for multilevel inverters. The main comparison criteria are the switching losses, the distortion in the load current, and the number of commutations. The main conclusion is that MPC is a competitive alternative to linear control for application in multilevel inverters.
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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.