Single-Switch Differential Power Processing PWM Converter to Enhance Energy Yield of Photovoltaic Panels under Partial Shading

The partial shading on a photovoltaic (PV) panel consisting of multiple substrings poses serious issues of decreased energy yield and occurrence of multiple maximum power points (MPPs). Although various kinds of differential power processing (DPP) converters have been proposed to prevent the partial shading issues, multiple switches and/or magnetic components in proportion to the number of substrings are necessary, hence increasing the circuit complexity and volume. This chapter proposes a novel single-switch DPP PWM converter to achieve simplified circuit. The proposed DPP converter is essentially the combination of a forward/flyback resonant inverter (FFRI) and voltage multiplier (VM). The fundamental operation analysis is performed, and the current sensorless control strategy suitable for the proposed DPP converter is also discussed. A 30-W prototype of the proposed DPP converter was built, and various kinds of experimental verification tests were performed emulating partial shading conditions. With the proposed DPP converter, local MPPs of a partially shaded PV panel were successfully eliminated, and energy yield was significantly enhanced, demonstrating the efficacy and performance of the proposed DPP converter

LLC Resonant Voltage Multiplier-Based Differential Power Processing Converter Using Voltage Divider with Reduced Voltage Stress for Series-Connected Photovoltaic Panels under Partial Shading

Partial shading on photovoltaic (PV) strings consisting of multiple panels connected in series is known to trigger severe issues, such as reduced energy yield and the occurrence of multiple power point maxima. Various kinds of differential power processing (DPP) converters have been proposed and developed to prevent partial shading issues. Voltage stresses of switches and capacitors in conventional DPP converters, however, are prone to soar with the number of panels connected in series, likely resulting in impaired converter performance and increased circuit volume. This paper proposes a DPP converter using an LLC resonant voltage multiplier (VM) with a voltage divider (VD) to reduce voltage stresses of switches and capacitors. The VD can be arbitrarily extended by adding switches and capacitors, and the voltage stresses can be further reduced by extending the VD. Experimental verification tests for four PV panels connected in series were performed emulating partial shading conditions in a laboratory and outdoor. The results demonstrated the proposed DPP converter successfully precluded the negative impacts of partial shading with mitigating the voltage stress issues

Usefulness of fetal magnetic resonance imaging for postnatal management of congenital lung cysts: prediction of probability for emergency surgery

Abstract Background Emergency rescue lung resection is rarely performed to treat congenital lung cysts (CLCs) in neonates. Many reports have described fetal CLC treatment; however, prenatal predictors for postnatal respiratory failure have not been characterized. We hypothesized that fetal imaging findings are useful predictors of emergency surgery. Methods We retrospectively studied patients with CLC who underwent lung surgery during the neonatal period in our hospital between January 2001 and December 2015. The demographic data, fetal imaging findings, and intra- and postoperative courses of patients who underwent emergency surgery (Em group) were compared with those of patients who received elective surgery, i.e., non-emergency surgery (Ne group). Results The Em group and Ne group included 7 and 11 patients, respectively. No significant difference was noted in gestational age, time at prenatal diagnosis, birth weight, and body weight at surgery. The volumes of contralateral lung per thoracic volume were significantly smaller in the Em group than in the Ne group (p = 0.0188). Mediastinal compression was more common in the Em group (7/7) than in the Ne group (4/11) (p = 0.0128). Conclusions This is the report describing neonatal emergency lobectomy in patients with CLC evaluated by fetal MRI using the lung volume ratio and mediastinal shift. In patients with CLC, mediastinal shift and significant decreases in contralateral lung volumes during the fetal stages are good prenatal predictors of postnatal emergency lung resection

Proton pump inhibitors and potassium competitive acid blockers decrease pembrolizumab efficacy in patients with metastatic urothelial carcinoma

Abstract We elucidated the efficacy of gut microbiome–altering drugs on pembrolizumab efficacy in patients with metastatic urothelial carcinoma (mUC). Clinical data were analyzed retrospectively from 133 patients with mUC who received second-line pembrolizumab therapy between January 2018 and January 2021, following failed platinum-based chemotherapy. We evaluated the effects of gut microbiome–altering drugs (proton pump inhibitors [PPI]/potassium-competitive acid blockers [P-CAB], H2 blockers, antibiotics, non-steroidal anti-inflammatory drugs [NSAIDs], metformin, antipsychotics, steroids, and opioids), taken by patients within 30 days before/after pembrolizumab treatment, on progression-free survival (PFS) and overall survival (OS). Fifty-one patients received PPI/P-CAB (37/14, respectively); H2 blockers, 7; antibiotics, 35; NSAIDs, 22; antipsychotics, 8; metformin, 3; steroids, 11; and opioids, 29. Kaplan–Meier curves revealed PPI or P-CAB users showed shorter PFS than non-PPI-P-CAB users (p = 0.001, p = 0.005, respectively). Multivariate analysis highlighted PPI/P-CAB use as the only independent prognostic factor for disease progression (hazards ratio: 1.71, 95% confidence interval: 1.14–2.07, p = 0.010) but not death (p = 0.177). Proton pump inhibitors/potassium-competitive acid blockers may decrease the efficacy of pembrolizumab therapy for mUC, possibly via gut microbiome modulation