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Dual-output hybrid converter based on the modular universal dcac/dc converter
(Nature Research, 2026) Gutiérrez Escalona, Javier; González Antúnez, José Javier; Roncero Clemente, Carlos; Matiushkin, Oleksandr; Pires, V. Fernão; Romero Cadaval, Enrique; Universidad de Extremadura. Departamento de Ingeniería Eléctrica, Electrónica y Automática; Tallinn University of Technology. Estonia; Instituto Politécnico de Setúbal. Portugal
With the increasing integration of renewable energy resources into modern electrical power systems, the development of distributed hybrid microgrids is becoming increasingly attractive because of their ability to operate in islanded mode and the coexistence of ac and dc buses. Power electronic converters, as critical technologies for these systems, increasingly require greater standardization and modularity. In this context, the modular universal converter topology emerged with the capability of operating as either a dc-dc or a dc-ac three-phase converter by featuring the same power stage with simple reconfiguration. This paper advances the MUC concept by introducing a modular dual-output hybrid converter that supplies a three-phase four-wire ac port and a regulated dc bus simultaneously using a single power-conversion stage, thereby replacing the conventional dual-output configuration based on separate dc-dc and dc-ac stages. The proposed architecture employs a modular arrangement of identical buck-boost cells in which three cells synthesize dc-biased sinusoidal phase voltages, while a fourth cell regulates the dc output and establishes the ac neutral by directly tying the neutral point to the positive dc terminal, enabling a common ground reference without galvanic isolation. Compared with previous MUC proposals that supply either ac or dc, the proposed converter delivers both simultaneously without reconfiguration. Simulation and laboratory measurements verify the converter operation using a regulated 200 V dc bus at a switching frequency of 62.5 kHz, demonstrating simultaneous delivery of 1 kW to the three-phase ac port and 800 W to the dc port with balanced sinusoidal ac waveforms, stable dc regulation, and fast, well-damped responses under both ac and dc load steps. These results demonstrate the feasibility of the proposed converter as a modular, single-stage dual-output solution for hybrid microgrids.
Comparative prognostic value of neutrophil-albumin-related ratios to predict mortality in dogs with acute pancreatitis
(Elsevier, 2025) Díaz González, Alba; Cristóbal Verdejo, José Ignacio; Espadas González, Lorena; Martínez Zafra, Carlos; Pérez Merino, Eva María; Universidad de Extremadura. Departamento de Medicina Animal
The prognostic value of hematological ratios incorporating neutrophils and albumin as key factors in the pathophysiology and outcome of acute pancreatitis (AP) in dogs needs assessment. This study compared the predictive power of the neutrophil count-to-lymphocyte ratio (NLR), neutrophil count-to-albumin ratio (NAR), neutrophil percentage-to-albumin ratio (NPAR), and NLR-to-albumin ratio (NLR-Alb) for in-hospital mortality in dogs with AP. This retrospective cohort study included 128 dogs with AP (59.37 % survivors / 40.63 % non-survivors) and 40 healthy dogs. NLR, NAR, NPAR, and NLR-Alb were calculated upon admission. Logistic regression and the area under the receiver-operating characteristic curve (AUROC) evaluated their predictive value. All markers were significantly higher in non-surviving dogs with AP than in survivors. A one-point increase in NLR, NLR-Alb, and NAR increased the mortality risk by 4 %, 12 %, and 16 %, respectively. The AUROC, sensitivity, and specificity at the cutoff for each marker were:.622, 62.75 %, and 61 % for NLR;.708, 64.7 %, and 75.3 % for NAR;.609, 78.4 %, and 44.2 % for NPAR;.649, 82.4 %, and 45.4 % for NLR-Alb. Values above their cutoffs increased the mortality risk by 2.42, 5.6, 2.87, and 3.69-fold, respectively. In conclusion, NAR can better predict outcomes in dogs with AP than NLR. NLR-Alb is also superior to NLR but exhibits low specificity in identifying non-survivors. NPAR offers no prognostic advantage over other markers. Using these markers to predict mortality may improve treatment efficiency in dogs with AP.
