A New Optimization Algorithm for Single Hidden Layer Feedforward Neural Networks

Feedforward neural networks are the most commonly used function approximation techniques in neural networks. By the universal approximation theorem, it is clear that a single-hidden layer feedforward neural network (FNN) is sufficient to approximate the corresponding desired outputs arbitrarily close. Some researchers use genetic algorithms (GAs) to explore the global optimal solution of the FNN structure. However, it is rather time consuming to use GA for the training of FNN. In this paper, we propose a new optimization algorithm for a single-hidden layer FNN. The method is based on the convex combination algorithm for massaging information in the hidden layer. In fact, this technique explores a continuum idea which combines the classic mutation and crossover strategies in GA together. The proposed method has the advantage over GA which requires a lot of preprocessing works in breaking down the data into a sequence of binary codes before learning or mutation can apply. Also, we set up a new error function to measure the performance of the FNN and obtain the optimal choice of the connection weights and thus the nonlinear optimization problem can be solved directly. Several computational experiments are used to illustrate the proposed algorithm, which has good exploration and exploitation capabilities in search of the optimal weight for single hidden layer FNNs

Temporal trends and patterns of infective endocarditis in a Chinese population:A territory-wide study in Hong Kong (2002-2019)

BACKGROUND: The characteristics of infective endocarditis (IE) in Asians are poorly understood. Therefore, we aim to describe the epidemiological trends and clinical features of IE in Hong Kong. METHODS: All patients with incident IE from 2002–2019 in a territory-wide clinical database in Hong Kong were identified. We studied the age- and sex-adjusted and one-year mortality of IE between 2002 and 2019 and identified significant contributors to 1-year all-cause death using the attributable fraction. We used propensity score and inverse propensity of treatment weighting to study the association of surgery with mortality. FINDINGS: A total of 5139 patients (60.4 ± 18.2years, 37% women) were included. The overall incidence of IE was 4.9 per 100,000 person-year, which did not change over time (P = 0.17). Patients in 2019 were older and more comorbid than those in 2002. The one-year crude mortality rate was 30% in 2002, which did not change significantly over time (P = 0.10). Between 2002 and 2019, the rate of surgery increased and was associated with a 51% risk reduction in 1-year all-cause mortality (Hazard Ratio 0.49 [0.28–0.87], P = 0.015). Advanced age (attributable fraction 19%) and comorbidities (attributable fraction 15%) were significant contributors to death. INTERPRETATION: The incidence of IE in Hong Kong did not change between 2002 and 2019. Patients with IE in 2019 were older and had more comorbidities than those in 2002. Mortality of IE remains persistently high in Hong Kong. Together, these data can guide public health strategies to improve the outcomes of patients with IE. FUNDING: This work was supported by Sanming Project of Medicine in Shenzhen, China [No. SZSM201911020] and HKU-SZH Fund for Shenzhen Key Medical Discipline [No. SZXK2020081]

Sex-based differences in risk of ischaemic stroke or systemic embolism after BNT162b2 or CoronaVac COVID-19 vaccination in patients with atrial fibrillation: a self-controlled case series and nested case-control study

AIMS: Patients with atrial fibrillation (AF) have a higher risk of ischemic stroke or systemic embolism with a greater risk for female patients. This study aims to evaluate the risk of ischemic stroke or systemic embolism and bleeding following COVID-19 vaccination in patients with AF and the sex differences. METHODS AND RESULTS: Self-controlled case series (SCCS) analysis was conducted to evaluate the risk of ischemic stroke or systemic embolism and bleeding following BNT162b2 or CoronaVac in patients with AF, using the territory-wide electronic medical records from the Hospital Authority and vaccination records from the Department of Health in Hong Kong. Patients with a primary diagnosis of ischemic stroke or systemic embolism or bleeding in the inpatient setting between February 23, 2021 and March 31, 2022 were included. A nested case-control analysis was also conducted with each case randomly matched with ten controls according to sex, age, Charlson comorbidity index and date of hospital admission. Conditional Poisson regression was used in the SCCS analysis and conditional logistic regression was used in nested case-control analysis to assess the risks and all analyses were stratified by sex and type of vaccines. Among 51 158 patients with AF, we identified an increased risk of ischemic stroke or systemic embolism after the first dose of BNT162b2 in SCCS analysis during 0-13 days (incidence rate ratio 6.60[95% CI 1.51-28.77]) and 14-27 days (6.53[95% CI 1.31-32.51]), and nested case-control analysis during 0-13 days (adjusted odds ratio 6.21 [95% CI 1.14-33.91]) and 14-27 days (5.52 [95% CI 1.12-27.26]) only in female patients. The increased risk in female patients following the first dose of CoronaVac was only detected during 0-13 days (3.88 [95% CI 1.67-9.03]) in the nested case-control analysis. No increased risk of ischemic stroke or systemic embolism was identified in male patients and no increased risk of bleeding was detected in all patients with AF for both vaccines. An increased risk of ischemic stroke or systemic embolism after COVID-19 was also observed in both females (17.42 [95% CI 5.08-59.73]) and males (6.63 [95% CI 2.02-21.79]). CONCLUSIONS: The risk of ischemic stroke or systemic embolism after COVID-19 vaccination was only increased in female patients with AF. However, as the risk after COVID-19 was even higher, proactive uptake of COVID-19 vaccines is recommended to prevent the potential severe outcomes after infection

Sex-based differences in risk of ischaemic stroke or systemic embolism after BNT162b2 or CoronaVac COVID-19 vaccination in patients with atrial fibrillation: a self-controlled case series and nested case-control study

AimsPatients with atrial fibrillation (AF) have a higher risk of ischaemic stroke or systemic embolism, with a greater risk for female patients. This study aims to evaluate the risk of ischaemic stroke or systemic embolism and bleeding following COVID-19 vaccination in patients with AF and the sex differences.Methods and resultsSelf-controlled case series (SCCS) analysis was conducted to evaluate the risk of ischaemic stroke or systemic embolism and bleeding following BNT162b2 or CoronaVac in patients with AF, using the territory-wide electronic medical records from the Hospital Authority and vaccination records from the Department of Health in Hong Kong. Patients with a primary diagnosis of ischaemic stroke, systemic embolism, or bleeding in the inpatient setting between 23 February 2021 and 31 March 2022 were included. A nested case-control analysis was also conducted with each case randomly matched with 10 controls according to sex, age, Charlson comorbidity index, and date of hospital admission. Conditional Poisson regression was used in the SCCS analysis, and conditional logistic regression was used in the nested case-control analysis to assess the risks, and all analyses were stratified by sex and type of vaccines. Among 51 158 patients with AF, we identified an increased risk of ischaemic stroke or systemic embolism after the first dose of BNT162b2 in SCCS analysis during 0-13 days [incidence rate ratio 6.60, 95% confidence interval (CI) 1.51-28.77] and 14-27 days (6.53, 95% CI 1.31-32.51), and nested case-control analysis during 0-13 days (adjusted odds ratio 6.21, 95% CI 1.14-33.91) and 14-27 days (5.52, 95% CI 1.12-27.26) only in female patients. The increased risk in female patients following the first dose of CoronaVac was only detected during 0-13 days (3.88, 95% CI 1.67-9.03) in the nested case-control analysis. No increased risk of ischaemic stroke or systemic embolism was identified in male patients, and no increased risk of bleeding was detected in all patients with AF for both vaccines. An increased risk of ischaemic stroke or systemic embolism after COVID-19 was also observed in both females (17.42, 95% CI 5.08-59.73) and males (6.63, 95% CI 2.02-21.79).ConclusionsThe risk of ischaemic stroke or systemic embolism after COVID-19 vaccination was only increased in female patients with AF. However, as the risk after COVID-19 was even higher, proactive uptake of COVID-19 vaccines is recommended to prevent the potential severe outcomes after infection

A New Optimization Algorithm for Single Hidden Layer Feedforward Neural Networks

Feedforward neural networks are the most commonly used function approximation techniques in neural networks. By the universal approximation theorem, it is clear that a single-hidden layer feedforward neural network (FNN) is sufficient to approximate the corresponding desired outputs arbitrarily close. Some researchers use genetic algorithms (GAs) to explore the global optimal solution of the FNN structure. However, it is rather time consuming to use GA for the training of FNN. In this paper, we propose a new optimization algorithm for a single-hidden layer FNN. The method is based on the convex combination algorithm for massaging information in the hidden layer. In fact, this technique explores a continuum idea which combines the classic mutation and crossover strategies in GA together. The proposed method has the advantage over GA which requires a lot of preprocessing works in breaking down the data into a sequence of binary codes before learning or mutation can apply. Also, we set up a new error function to measure the performance of the FNN and obtain the optimal choice of the connection weights and thus the nonlinear optimization problem can be solved directly. Several computational experiments are used to illustrate the proposed algorithm, which has good exploration and exploitation capabilities in search of the optimal weight for single hidden layer FNNs

Epitaxy-like protective layers for high-performance low-cost Au/Pd/Ni preplated Cu alloy leadframes

In this paper, we report the performance, the crystal microstructure, and defects of Au/Pd/Ni/Cu preplated lead frames (PPF). The wire pull test, the solderability test, and high-resolution transmission electron microscopy (HRTEM) are employed to characterize the PPFs in order to understand the relationship between performance and microstructure. The electroplated PPFs are composed of Au (3 nm)/Pd (5 to 15 nm)/Ni (0.7 mu m)/Cu substrate. We optimize the electroplating profile and determine the minimum thickness of the Pd layer with the PPF performance satisfying the industry standards. Further increasing the Pd layer thickness beyond the critical thickness will not enhance the performance more, but increase the product cost. With the optimized electroplating profile, the electroplated Au layer is epitaxially deposited on the I'd layer, and so does the Pd layer on the Ni layer. The interface between the Au and Pd layers is in general coherent in spite of the about 4.8\% mismatch strain between the An and Pd lattices because the Au layer thickness is only 3 nm small. Misfit dislocations and nanotwins are present at the interface between the I'd and Ni layers, which are generated to release the about 10.4\% misfit strain between the Pd and Ni lattices

Recurrent respiratory papillomatosis (RRP) of tracheobronchial tree presenting as lung collapse with malignant transformation after a decade

Recurrent respiratory papillomatosis is a rare disease caused by HPV infection. We hereby report a patient with recurrent respiratory papillomatosis of the tracheobronchial tree with no laryngeal involvement who remained clinically stable for more than 10 years but then developed malignant transformation with metastases.A 61-year-old lady with good past health presented to our department in 2010 because of chronic cough for years. Chest X-ray showed reduced left lung volume. Bronchoscopy showed multiple nodules over left main bronchus and left upper lobe progressing to involve the posterior trachea and left lower lobe. Biopsy revealed squamous papilloma with mild dysplasia. She refused surgical intervention. She remained relatively stable until November 2022 when she developed left chest pain. CT showed features of malignant transformation with local invasion and metastases. Fine needle aspiration suggested squamous cell carcinoma. She succumbed in December 2022.Bronchoscopy should be considered in the investigation of unexplained chronic cough so that this rare disease can be detected at an early stage. The disease may not require intervention if uncomplicated. Despite clinical stability for a prolonged period, close monitoring for malignant transformation is warranted indefinitely

Association of time to prostate-specific antigen nadir and logarithm of prostate-specific antigen velocity after progression in metastatic prostate cancer with prior primary androgen deprivation therapy

We investigated the association of time to prostate-specific antigen nadir (TTPN) and logarithm of prostate-specific antigen velocity after progression Log(PSAVAP) in metastatic prostate cancer with prior primary androgen deprivation therapy (ADT). All metastatic prostate cancer patients treated with primary ADT from 2000 to 2009 were reviewed. Patients who developed disease progression were included in the subsequent analyses. Patients were categorized into three groups according to their TTPN: TTPN of 17 months. We compared the Log(PSAVAP) between the different TTPN groups using Mann-Whitney U-test and Kruskal-Wallis test. Further multiple linear regression analyses on Log(PSAVAP) were performed to adjust for other potential confounding factors. Among 419 patients who were treated with primary ADT, 306 patients developed disease progression with a median follow-up of 28 months. Longer TTPN was associated with lower Log(PSAVAP) (P = 0.008) within all subgroup analyses (TTPN of 17 months, P= 0.009; and TTPN of 17 months, P= 0.001). Upon multiple linear regression analyses, baseline PSA (regression coefficient 0.001, P= 0.045), PSA nadir (regression coefficient 0.002, P= 0.040), and TTPN (regression coefficient −0.030, P= 0.001) were the three factors that were significantly associated with Log(PSAVAP). In conclusion, a longer TTPN was associated with lower Log(PSAVAP) in metastatic prostate cancer patients following primary ADT. TTPN cut-offs at 3 months and 17 months appeared to have prognostic significance in predicting Log(PSAVAP). TTPN may serve as a good prognostic indicator in deciding the treatment strategy in patients with disease progression