FIXED-POLE ACTIVE PI FILTER DESIGN FOR HIGH FREQUENCY NONLINEAR PLL MODELS

A Phase-locked loop (PLL) is a basic control system that attempts to produce an output waveform that can match with the input reference signal in the shortest time possible. A filter is one of the main components in the PLL blocks, and it plays a very important role to determine the range of input frequency that can ensure the system stays in a locked condition. This paper focuses on designing a fixed-pole active PI filter which is suitable for high-frequency PLL-based circuits such as those used in clock generators. As PLL is bound to fall out of lock due to the nonlinear effects from its phase detector, a new approach is introduced in this work which is to combine the linear and nonlinear control method to ensure stability. Having had the phase margin specified a priori, it is shown by simulation that the allowable range of input frequency such that the system remains locked can be expanded

Angiopoietin-like 4: a decade of research

The past decade has seen a rapid development and increasing recognition of ANGPTL4 (angiopoietin-like 4) as a remarkably multifaceted protein that is involved in many metabolic and non-metabolic conditions. ANGPTL4 has been recognised as a central player in various aspects of energy homoeostasis, at least in part, via the inhibitory interaction between the coiled-coil domain of ANGPTL4 and LPL (lipoprotein lipase). The fibrinogen-like domain of ANGPTL4 interacts and activates specific integrins to facilitate wound healing, modulates vascular permeability, and regulates ROS (reactive oxygen species) level to promote tumorigenesis. The present review summarizes these landmark findings about ANGPTL4 and highlights several important implications for future clinical practice. Importantly, these implications have also raised many questions that are in urgent need of further investigations, particularly the transcription regulation of ANGPTL4 expression, and the post-translation cleavage and modifications of ANGPTL4. The research findings over the past decade have laid the foundation for a better mechanistic understanding of the new scientific discoveries on the diverse roles of ANGPTL4

There is detectable variation in the lipidomic profile between stable and progressive patients with idiopathic pulmonary fibrosis (IPF)

Background Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial lung disease characterized by fibrosis and progressive loss of lung function. The pathophysiological pathways involved in IPF are not well understood. Abnormal lipid metabolism has been described in various other chronic lung diseases including asthma and chronic obstructive pulmonary disease (COPD). However, its potential role in IPF pathogenesis remains unclear. Methods In this study, we used ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) to characterize lipid changes in plasma derived from IPF patients with stable and progressive disease. We further applied a data-independent acquisition (DIA) technique called SONAR, to improve the specificity of lipid identification. Results Statistical modelling showed variable discrimination between the stable and progressive subjects, revealing differences in the detection of triglycerides (TG) and phosphatidylcholines (PC) between progressors and stable IPF groups, which was further confirmed by mass spectrometry imaging (MSI) in IPF tissue. Conclusion This is the first study to characterise lipid metabolism between stable and progressive IPF, with results suggesting disparities in the circulating lipidome with disease progression

Gastroesophageal reflux and antacid therapy in IPF: analysis from the Australia IPF Registry

BACKGROUND AND OBJECTIVE:Gastroesophageal reflux disease (GORD) is highly prevalent in idiopathic pulmonary fibrosis (IPF) and may play a role in its pathogenesis. Recent IPF treatment guidelines suggest that all patients with IPF be considered for antacid therapy. However, emerging evidence suggests that antacid therapy does not improve IPF patient outcomes and may increase the risk of pulmonary infection. METHODS:Using prospectively collected data from the Australian IPF Registry including use of antacid therapy, GORD diagnosis and GORD symptoms, the relationship of these GORD variables to survival and disease progression was assessed. The severity of GORD symptoms using the frequency scale for symptoms of GORD (FSSG) and its relationships to outcomes was also assessed for the first time in an IPF cohort. RESULTS:Five hundred eighty-seven (86%) of the 684 patients in the Australian IPF Registry were eligible for inclusion. Patients were mostly male (69%), aged 71.0 ± 8.5 years with moderate disease (FVC 81.7 ± 21.5%; DLco 48.5 ± 16.4%). Most patients were taking antacids (n = 384; 65%), though fewer had a diagnosis of GORD (n = 243, 41.4%) and typical GORD symptoms were even less common (n = 171, 29.1%). The mean FSSG score was 8.39 ± 7.45 with 43% (n = 251) having a score > 8. Overall, there was no difference in survival or disease progression, regardless of antacid treatment, GORD diagnosis or GORD symptoms. CONCLUSIONS:Neither the use of antacid therapy nor the presence of GORD symptoms affects longer term outcomes in IPF patients. This contributes to the increasing evidence that antacid therapy may not be beneficial in IPF patients and that GORD directed therapy should be considered on an individual basis to treat the symptoms of reflux.Helen E. Jo, Tamera J. Corte, Ian Glaspole, Christopher Grainge, Peter M. A. Hopkins ... Peter A. Bampton ... et al

The Cholecystectomy As A Day Case (CAAD) Score: A Validated Score of Preoperative Predictors of Successful Day-Case Cholecystectomy Using the CholeS Data Set

Background Day-case surgery is associated with significant patient and cost benefits. However, only 43% of cholecystectomy patients are discharged home the same day. One hypothesis is day-case cholecystectomy rates, defined as patients discharged the same day as their operation, may be improved by better assessment of patients using standard preoperative variables. Methods Data were extracted from a prospectively collected data set of cholecystectomy patients from 166 UK and Irish hospitals (CholeS). Cholecystectomies performed as elective procedures were divided into main (75%) and validation (25%) data sets. Preoperative predictors were identified, and a risk score of failed day case was devised using multivariate logistic regression. Receiver operating curve analysis was used to validate the score in the validation data set. Results Of the 7426 elective cholecystectomies performed, 49% of these were discharged home the same day. Same-day discharge following cholecystectomy was less likely with older patients (OR 0.18, 95% CI 0.15–0.23), higher ASA scores (OR 0.19, 95% CI 0.15–0.23), complicated cholelithiasis (OR 0.38, 95% CI 0.31 to 0.48), male gender (OR 0.66, 95% CI 0.58–0.74), previous acute gallstone-related admissions (OR 0.54, 95% CI 0.48–0.60) and preoperative endoscopic intervention (OR 0.40, 95% CI 0.34–0.47). The CAAD score was developed using these variables. When applied to the validation subgroup, a CAAD score of ≤5 was associated with 80.8% successful day-case cholecystectomy compared with 19.2% associated with a CAAD score >5 (p < 0.001). Conclusions The CAAD score which utilises data readily available from clinic letters and electronic sources can predict same-day discharges following cholecystectomy

Perforation of the large bowel during colonoscopy in Singapore

American Surgeon565285-288AMSU

How I do it: Laparoscopic cholecystectomy

10.1007/BF02391087Journal of Hepato-Biliary-Pancreatic Surgery13309-313JHBS

Interstitial lung disease in Sjogren's syndrome

Sjogrens syndrome (SS), whether primary, or secondary to other autoimmune rheumatic diseases, is classically associated with the sicca complex of keratoconjunctivits and xerostomia. However, extraglandular manifestations are also relatively common, affecting up to 25% of patients. In this article, we discuss respiratory system involvement in SS, with a focus on interstitial lung disease (ILD). We review the histopathologic variants, clinical features, diagnosis and treatment of SS-ILD. Novel and emerging diagnostic and prognostic biomarkers for SS-ILD are also discussed. We offer an approach to the management of SS-ILD including possible goals of therapy. We conclude by highlighting areas for future research.Mandana Nikpour, Susanna M. Proudman, Nicole S. Goh and Haralampos M. Moutsopoulo