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On the Role of Switch Output Capacitance on Passive Balancing Within the Flying Capacitor Multilevel Converter
Get PDFFlying capacitor multilevel (FCML) converters typically rely on natural balancing to achieve a balanced distribution of flying capacitor voltages. The mechanisms by which the flying capacitor voltages are able to balance have been extensively studied and theoretically there are certain combinations of level count and duty cycle at which the flying capacitor voltages do not balance. Although the flying capacitor voltages should diverge from the balanced distribution, in practice this behavior is rarely observed. To resolve this discrepancy between FCML converter theory and experiment, this article analyzes the impact of switch output capacitance on the flying capacitor voltage balancing dynamics, and illustrates that this capacitance has a naturally balancing effect. The additional mechanism of switch output capacitance induced balancing is analytically described and compared against experimental results on several FCML converter prototypes
Dermatology education in U.S. ophthalmology residency: a survey of the program directors.
Get PDFBACKGROUND: Many ocular conditions have associated dermatological findings. However, the inclusion of dermatology education in U.S. Ophthalmology residency programs remains limited. This study aims to characterize dermatology education in U.S. ophthalmology residency programs through program directors (PDs) opinions. METHOD: The authors designed and electronically distributed a national survey in August 2022 to PDs of 124 ophthalmology residency programs. The survey instruments examined the availability and characteristics of dermatology rotation, the PDs perceptions of such rotation, and their perspectives on trainees dermatology knowledge. Descriptive statistics were used to summarize survey responses. Sample t-tests were used to compare responses between PDs from programs with and without dermatology rotation. RESULTS: 49 PDs (39.5%) responded to the survey. Most programs (n = 27 [61.4%]) did not offer dermatology rotations and, of these programs, most (n = 15 [83.3%]) did not consider increasing dermatology exposure important. 57.1% (n = 8) of PDs at residency programs with dermatology rotation considered such education beneficial for their trainees. Most PDs do not consider their residents comfortable with procedures such as laser or cryotherapy, procedures relevant to ocular care. CONCLUSION: Dermatology rotations were uncommon among U.S. ophthalmology residencies. Perceptions towards dermatology education varied among PDs, with those from programs with dermatology rotation expressing more favorable opinions
α-Synuclein Seed Amplification Assay Amplification Parameters and the Risk of Progression in Prodromal Parkinson Disease
Get PDFObjectivesTools are needed to evaluate the risk of developing Parkinson disease (PD) in at-risk populations. In this study, we examine differences in alpha-synuclein seed amplification assay (αSyn-SAA) qualitative results and amplification parameters between nonmanifesting carriers (NMCs) of PD-related pathogenic variants, prodromal PD, and PD and the risk of developing a synucleinopathy in participants with prodromal PD.MethodsCross-sectional and longitudinal CSF αSyn-SAA results from participants in the Parkinson's Progression Markers Initiative were analyzed. αSyn-SAA positivity and amplification parameters (maximum fluorescence [Fmax], time-to-threshold [TTT], time-to-50% Fmax [T50], and area under the curve [AUC]) were compared between NMCs, participants with prodromal PD, and participants with PD, and their relationship with the likelihood of phenoconversion in participants with prodromal PD was investigated.ResultsSamples from 1,027 participants were analyzed (159 healthy controls [HCs], 247 NMCs, 96 participants with prodromal PD, and 525 participants with PD). TTT and T50 were faster, and AUC was higher in αSyn-SAA+ participants with prodromal PD and PD than αSyn-SAA+ NMCs and HC participants (Kruskal-Wallis χ2 = 4.15-13.96, p < 0.0002-0.04). Participants with prodromal PD with positive αSyn-SAA tests and faster TTT had higher rates of phenoconversion (log-rank p = 0.001 and log-rank test-for-trend p < 0.0001). There were no changes in 48 participants with prodromal PD with longitudinal assays.DiscussionαSyn-SAA positivity and faster seed amplification are associated with a greater risk of developing PD in at-risk individuals and may aid in predicting phenoconversion
Iterative Intraperitoneal Chemotherapy in Gastric Cancer Peritoneal Carcinomatosis.
Get PDFBackground/objectives: Despite the incremental improvement of survival with systemic therapy in metastatic gastric cancer (GC), the outcomes of patients with peritoneal carcinomatosis (PC) remain poor. The limited effectiveness of systemic therapy is attributed to the blood-peritoneal barrier and anarchic intra-tumoral circulation, which reduce the penetration of systemic therapy. Approaches that incorporate intraperitoneal (IP) chemotherapy, in addition to systemic therapies, may be a viable alternate strategy. Therefore, we provide a review of biology of gastric cancer peritoneal metastasis and evidence for bidirectional iterative IP chemotherapy in GCPC. Methods: A comprehensive search in PubMed, Scopus, Embase, Web of Science, Google Scholar, and ClinicalTrials.gov was performed to find the relevant articles and ongoing phase II/III clinical trials in iterative IP chemotherapy in GCPC. Results: Intraperitoneal (IP) chemotherapy leverages the blood-peritoneal barrier to allow for the administration of high concentrations of chemotherapy directly to the peritoneal metastases, with a significant reduction in the systemic toxicity and enhanced drug efficacy against peritoneal metastasis. This pharmacokinetic advantage of IP chemotherapy can be further enhanced by additional measures such as heat or aerosolization. There are three IP chemotherapy approaches, namely, heated intraperitoneal chemotherapy (HIPEC), pressurized intraperitoneal aerosolized chemotherapy (PIPAC), and normothermic intraperitoneal chemotherapy (NIPEC). Recent evidence suggests that iterative IP chemotherapy combined with systemic therapy may offer significant survival benefits for patients with peritoneal metastasis. Furthermore, bidirectional treatment approaches may also increase the chances of surgical resection and survival. Conclusions: IP chemotherapy plays a pivotal role in the management of gastric carcinomatosis, particularly in combination with cytoreduction in highly selected patients. The combination of systemic and regional control may increase the chances of surgical resection and may ultimately lead to significant survival benefits
Role of imaging in the diagnosis and management of mixed epithelial and stromal tumors of the kidney: Case series and comprehensive review.
Get PDFMixed epithelial and stromal tumor (MEST) of the kidney is a rare benign neoplasm composed of both stromal and epithelial components. MEST is mainly seen in adults with a strong predilection for perimenopausal women with history of hormone replacement therapy. While MEST is generally benign, there are reported cases of malignant transformation and adverse clinical outcomes. This case series will present 7 cases of this rare renal neoplasm with emphasis on radiological imaging as an important tool in the guidance of clinical management. Considering the rarity of this tumor and its variable presentation, understanding the radiological features on multiple modalities can guide appropriate clinical and surgical management of MEST patients
Imagining Coat‐Hangers and Pills: A Qualitative Exploration of Abortion Beliefs and Attitudes in Hostile Policy Contexts in the United States
Get PDFObjectiveWe explored awareness of and attitudes about the safety of various methods people use to attempt to end a pregnancy without medical assistance, which we refer to in this study collectively as self-managed abortion (SMA).MethodsIn 2020, we invited individuals living in eight United States (US) states considered "hostile" to abortion rights or with a history of criminalizing abortions performed outside the formal healthcare system to participate in semi-structured telephone interviews regarding their attitudes toward these practices. We analyzed coded transcripts for content and themes.ResultsWe interviewed 54 individuals. Participants perceived methods of ending a pregnancy on one's own to have a high potential for complications, often evoking "coat hanger" abortions. Participants also frequently referenced methods such as physical trauma, herbs, teas, alcohol, or other drugs. Very few participants reported awareness of medication abortion pills. When asked about the safety of SMA in the context of self-sourcing these medications, participants considered pills safer and more acceptable than other SMA methods, while still fearing incorrect use and complications. Others believed that SMA could offer greater reproductive autonomy, less stigma, and a safer physical and psychological experience than facility-based abortion care.ConclusionIn 2020, most participants perceived SMA as involving unsafe practices and did not include use of medication abortion pills. Future research should document how beliefs and attitudes have been influenced by the expansion in telemedicine provision of medication abortion, the implementation of new state abortion bans, and the promulgation of Shield Laws
RUNX2 promotes fibrosis via an alveolar-to-pathological fibroblast transition
Get PDFA hallmark of pulmonary fibrosis is the aberrant activation of lung fibroblasts into pathological fibroblasts that produce excessive extracellular matrix1-3. Thus, the identification of key regulators that promote the generation of pathological fibroblasts can inform the development of effective countermeasures against disease progression. Here we use two mouse models of pulmonary fibrosis to show that LEPR+ fibroblasts that arise during alveologenesis include SCUBE2+ alveolar fibroblasts as a major constituent. These alveolar fibroblasts in turn contribute substantially to CTHRC1+POSTN+ pathological fibroblasts. Genetic ablation of POSTN+ pathological fibroblasts attenuates fibrosis. Comprehensive analyses of scRNA-seq and scATAC-seq data reveal that RUNX2 is a key regulator of the expression of fibrotic genes. Consistently, conditional deletion of Runx2 with LeprcreERT2 or Scube2creERT2 reduces the generation of pathological fibroblasts, extracellular matrix deposition and pulmonary fibrosis. Therefore, LEPR+ cells that include SCUBE2+ alveolar fibroblasts are a key source of pathological fibroblasts, and targeting Runx2 provides a potential treatment option for pulmonary fibrosis
