Quality of life in patients with diabetic nephropathy: findings from the KNOW-CKD (Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease) cohort

Background Diabetic nephropathy (DN) can affect quality of life (QoL) because it requires arduous lifelong management. This study analyzed QoL differences between DN patients and patients with other chronic kidney diseases (CKDs). Methods The analysis included subjects (n = 1,766) from the KNOW-CKD (Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease) cohort who completed the Kidney Disease Quality of Life Short Form questionnaire. After implementing propensity score matching (PSM) using factors that affect the QoL of DN patients, QoL differences between DN and non-DN participants were examined. Results Among all DN patients (n = 390), higher QoL scores were found for taller subjects, and lower scores were found for those who were unemployed or unmarried, received Medical Aid, had lower economic status, had higher platelet counts or alkaline phosphatase levels, or used clopidogrel or insulin. After PSM, the 239 matched DN subjects reported significantly lower patient satisfaction (59.9 vs. 64.5, p = 0.02) and general health (35.3 vs. 39.1, p = 0.04) than the 239 non-DN subjects. Scores decreased in both groups during the 5-year follow-up, and the scores in the work status, sexual function, and role-physical domains were lower among DN patients than non-DN patients, though those differences were not statistically significant. Conclusion Socioeconomic factors of DN were strong risk factors for impaired QoL, as were high platelet, alkaline phosphatase, and clopidogrel and insulin use. Clinicians should keep in mind that the QoL of DN patients might decrease in some domains compared with non-DN CKDs

Prevalence and detection of low-allele-fraction variants in clinical cancer samples

Accurate detection of genomic alterations using high-throughput sequencing is an essential component of precision cancer medicine. We characterize the variant allele fractions (VAFs) of somatic single nucleotide variants and indels across 5095 clinical samples profiled using a custom panel, CancerSCAN. Our results demonstrate that a significant fraction of clinically actionable variants have low VAFs, often due to low tumor purity and treatment-induced mutations. The percentages of mutations under 5% VAF across hotspots in EGFR, KRAS, PIK3CA, and BRAF are 16%, 11%, 12%, and 10%, respectively, with 24% for EGFR T790M and 17% for PIK3CA E545. For clinical relevance, we describe two patients for whom targeted therapy achieved remission despite low VAF mutations. We also characterize the read depths necessary to achieve sensitivity and specificity comparable to current laboratory assays. These results show that capturing low VAF mutations at hotspots by sufficient sequencing coverage and carefully tuned algorithms is imperative for a clinical assay

Comparative Analysis of Voltage Control in Battery Power Converters for Inverter-Based AC Microgrids

A microgrid is a micro-power system composed of local distributed generators, energy storage systems, loads, and other components in a local power network. Because renewable energy sources show relatively large output power variation, the integration of distributed generators in a microgrid often requires the installation of a large-scale energy storage system. The energy storage system is connected to a local AC bus via the DC/AC converter with an output inductor-capacitor (LC) filter. The energy storage system power converters generally form the local AC bus voltage. This grid-forming operation requires fast and robust voltage control to properly maintain a stable energy flow and high power quality in the local AC bus. In this paper, two major voltage control schemes—double-loop control and direct voltage control—are analytically compared, and their effects on the power quality of the microgrid are illustrated. The dynamic performance is compared through simulations and experimental results

Design and Field Tests of an Inverted Based Remote MicroGrid on a Korean Island

In this paper, we present the results of an economic feasibility study and propose a system structure to test and maintain electrical stability. In addition, we present real operation results after constructing a remote microgrid on an island in South Korea. To perform the economic feasibility study, a commercial tool called HOMER was used. The developed remote microgrid consists of a 400 kW wind turbine (WT) generator, 314 kW photovoltaic (PV) generator, 500 kVA × 2 grid forming inverter, 3 MWh lithium ion battery, and an energy management system (EMS). The predicted renewable energy fraction was 91% and real operation result was 82%. The frequency maintaining rate of the diesel power plants was 57% but the remote microgrid was 100%. To improve the operating efficiency of the remote microgrid, we investigated the output range of a diesel generator

Metastable defect curing by alkaline earth metal in chalcogenide thin-film solar cells

This study investigates the use of an alkaline earth metal precursor (MgF2) to enhance the performance of chalcogenide-based Cu(In,Ga)Se2 (CIGS) solar cells with a chemically bath deposited-Zn(O,S) (CBD-Zn(O,S)) buffer layer via post-deposited treatment (PDT). The optimal substrate temperature and layer thickness are 570 °C and 5 nm, and the light soaking (LS) treatment does not be required in this condition. The morphological properties and chemical reaction at the p-n junction of CIGS/CBD-Zn(O,S) are examined as a function of MgF2 PDT layer thickness. As the MgF2 PDT layer thickness increases, the CIGS surface becomes rough with vigorously agglomerated Cu clusters owing to the substantially high substrate temperature, which increases the incorporation of In-Se bonds and the oxygenation rate of MgF2. Density functional theory (DFT) clarifies the improved cell efficiency without the need for LS treatment (MgF2 PDT, 5 nm) by calculating the defect-related electronic behavior. The MgF2 phase effectively passivates metastable defect Cu-Se vacancy defects (VCu-Se), related to the LS effect without the additional formation of deep-level defect states into the CIGS bandgap. Moreover, VCu-Se states exert the most influence on the LS effect, and the control of defect states in the CIGS layer (not the buffer layer) is crucial for cell efficiency