Using Nyquist or Nyquist-Like Plot to Predict Three Typical Instabilities in DC-DC Converters

By transforming an exact stability condition, a new Nyquist-like plot is proposed to predict occurrences of three typical instabilities in DC-DC converters. The three instabilities are saddle-node bifurcation (coexistence of multiple solutions), period-doubling bifurcation (subharmonic oscillation), and Neimark bifurcation (quasi-periodic oscillation). In a single plot, it accurately predicts whether an instability occurs and what type the instability is. The plot is equivalent to the Nyquist plot, and it is a useful design tool to avoid these instabilities. Nine examples are used to illustrate the accuracy of this new plot to predict instabilities in the buck or boost converter with fixed or variable switching frequency.Comment: Submitted to an IEEE journal in 201

Biola Hour Highlights, 1976 - 04

Old Age by Al Sanders Lessons from the Word by Charles Swindoll Will We Know Our Loved Ones in Heaven? by Lehman Strauss Revelation by Lloyd Anderson Panel Discussion with Richard Chase, Charles Feinberg, and Samuel Sutherlandhttps://digitalcommons.biola.edu/bhhs/1026/thumbnail.jp

EQUIP: Implementing chronic care principles and applying formative evaluation methods to improve care for schizophrenia: QUERI Series

<p>Abstract</p> <p>Background</p> <p>This paper presents a case study that demonstrates the evolution of a project entitled "Enhancing QUality-of-care In Psychosis" (EQUIP) that began approximately when the U.S. Department of Veterans Affairs' Quality Enhancement Research Initiative (QUERI), and implementation science were emerging. EQUIP developed methods and tools to implement chronic illness care principles in the treatment of schizophrenia, and evaluated this implementation using a small-scale controlled trial. The next iteration of the project, EQUIP-2, was further informed by implementation science and the use of QUERI tools.</p> <p>Methods</p> <p>This paper reports the background, development, results and implications of EQUIP, and also describes ongoing work in the second phase of the project (EQUIP-2). The EQUIP intervention uses implementation strategies and tools to increase the adoption and implementation of chronic illness care principles. In EQUIP-2, these strategies and tools are conceptually grounded in a stages-of-change model, and include clinical and delivery system interventions and adoption/implementation tools. Formative evaluation occurs in conjunction with the intervention, and includes developmental, progress-focused, implementation-focused, and interpretive evaluation.</p> <p>Results</p> <p>Evaluation of EQUIP provided an understanding of quality gaps <it>and </it>how to address related problems in schizophrenia. EQUIP showed that solutions to quality problems in schizophrenia differ by treatment domain and are exacerbated by a lack of awareness of evidence-based practices. EQUIP also showed that improving care requires creating resources for physicians to help them easily implement practice changes, plus intensive education as well as product champions who help physicians use these resources. Organizational changes, such as the addition of care managers and informatics systems, were shown to help physicians with identifying problems, making referrals, and monitoring follow-up. In EQUIP-2, which is currently in progress, these initial findings were used to develop a more comprehensive approach to implementing and evaluating the chronic illness care model.</p> <p>Discussion</p> <p>In QUERI, small-scale projects contribute to the development and enhancement of hands-on, action-oriented service-directed projects that are grounded in current implementation science. This project supports the concept that QUERI tools can be useful in implementing complex care models oriented toward evidence-based improvement of clinical care.</p

Fecal occult blood and fecal calprotectin as point-of-care markers of intestinal morbidity in Ugandan children with Schistosoma mansoni infection.

BACKGROUND: Calprotectin is a calcium-binding cytoplasmic protein found in neutrophils and increasingly used as a marker of bowel inflammation. Fecal occult blood (FOB) is also a dependable indicator of bowel morbidity. The objective of our study was to determine the applicability of these tests as surrogate markers of Schistosoma mansoni intestinal morbidity before and after treatment with praziquantel (PZQ). METHODS: 216 children (ages 3-9 years old) from Buliisa District in Lake Albert, Uganda were examined and treated with PZQ at baseline in October 2012 with 211 of them re-examined 24 days later for S. mansoni and other soil transmitted helminths (STH). POC calprotectin and FOB assays were performed at both time points on a subset of children. Associations between the test results and infection were analysed by logistic regression. RESULTS: Fecal calprotectin concentrations of 150-300 µg/g were associated with S. mansoni egg patent infection both at baseline and follow up (OR: 12.5 P = 0.05; OR: 6.8 P = 0.02). FOB had a very strong association with baseline anemia (OR: 9.2 P = 0.03) and medium and high egg intensity schistosomiasis at follow up (OR: 6.6 P = 0.03; OR: 51.3 P = 0.003). Both tests were strongly associated with heavy intensity S. mansoni infections. There was a significant decrease in FOB and calprotectin test positivity after PZQ treatment in those children who had egg patent schistosomiasis at baseline. CONCLUSIONS: Both FOB and calprotectin rapid assays were found to correlate positively and strongly with egg patent S. mansoni infection with a positive ameloriation response after PZQ treatment indicative of short term reversion of morbidity. Both tests were appropriate for use in the field with excellent operational performance and reliability. Due to its lower-cost which makes its scale-up of use affordable, FOB could be immediately adopted as a monitoring tool for PC campaigns for efficacy evaluation before and after treatment

Performance characteristics of EUS for locoregional evaluation of ampullary lesions

Background The accuracy of EUS in the locoregional assessment of ampullary lesions is unclear. Objectives To compare EUS with ERCP and surgical pathology for the evaluation of intraductal extension and local staging of ampullary lesions. Design Retrospective cohort study. Setting Tertiary-care referral center. Patients All patients who underwent EUS primarily for the evaluation of an ampullary lesion between 1998 and 2012. Intervention EUS. Main Outcome Measurements Comparison of EUS sensitivity/specificity for intraductal and local extension with ERCP and surgical pathology by using the area under the receiver-operating characteristic (AUROC) curves and outcomes of the subgroup referred for endoscopic papillectomy. Results We identified 119 patients who underwent EUS for an ampullary lesion, of whom 99 (83%) had an adenoma or adenocarcinoma. Compared with ERCP (n = 90), the sensitivity/specificity of EUS for any intraductal extension was 56%/97% (AUROC = 0.77; 95% confidence interval [CI], 0.64-0.89). However, when using surgical pathology as the reference (n = 102), the sensitivity/specificity of EUS (80%/93%; AUROC = 0.87; 95% CI, 0.76-0.97) and ERCP (83%/93%; AUROC = 0.88; 95% CI, 0.77-0.99) were comparable. The overall accuracy of EUS for local staging was 90%. Of 58 patients referred for endoscopic papillectomy, complete resection was achieved in 53 (91%); in those having intraductal extension by EUS or ERCP, complete resection was achieved in 4 of 5 (80%) and 4 of 7 (57%), respectively. Limitation Retrospective design. Conclusions EUS and ERCP perform similarly in evaluating intraductal extension of ampullary adenomas. Additionally, EUS is accurate in T-staging ampullary adenocarcinomas. Future prospective studies should evaluate whether EUS can identify characteristics of ampullary lesions that appropriately direct patients to endoscopic or surgical resection. (Gastrointest Endosc 2015;81:380-8.

Primary PEComa of the bladder treated with primary excision and adjuvant interferon-alpha immunotherapy: a case report

BACKGROUND: Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal neoplasms of uncertain malignant potential, which have in common the co-expression of muscle and melanocytic immunohistochemical markers. CASE PRESENTATION: A 48-year-old man presented with dysuria, passage of urinary sediment and lower abdominal discomfort. A three centimeter mass was identified by cystoscopy in the posterior midline of the bladder. Computerized tomography suggested an enterovesical fistula. The patient underwent laparotomy, partial cystectomy and partial small bowel resection. Pathological examination revealed PEComa of the bladder. The patient underwent adjuvant interferon-α immunotherapy. Subsequent follow-up procedures, including cystoscopy and imaging, have not revealed evidence of recurrence. The patient is clinically free of disease 48 months after surgery. CONCLUSION: This case represents the second documented PEComa of bladder and demonstrates that adjuvant therapies, including anti-angiogenic and immunotherapy, may be considered for patients with locally advanced or metastatic genitourinary PEComa

Factors that influence the provision of good-quality routine antenatal services: a qualitative evidence synthesis of the views and experiences of maternity care providers [Protocol]

This is a protocol for a Cochrane Review (Qualitative). The objectives are as follows: - To identify the factors influencing the provision of quality ANC according to health care providers - To explore how these factors relate to, and help to explain the findings of, the related Cochrane intervention review