Microstructural evolution of epitaxial dielectric films derived from chemical precursors

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1995.Includes bibliographical references (leaves 138-150).by Man Fai Ngg.Ph.D

A metaheuristic-based framework for index tracking with practical constraints

Recently, numerous investors have shifted from active strategies to passive strategies because the passive strategy approach affords stable returns over the long term. Index tracking is a popular passive strategy. Over the preceding year, most researchers handled this problem via a two-step procedure. However, such a method is a suboptimal global-local optimization technique that frequently results in uncertainty and poor performance. This paper introduces a framework to address the comprehensive index tracking problem (IPT) with a joint approach based on metaheuristics. The purpose of this approach is to globally optimize this problem, where optimization is measured by the tracking error and excess return. Sparsity, weights, assets under management, transaction fees, the full share restriction, and investment risk diversification are considered in this problem. However, these restrictions increase the complexity of the problem and make it a nondeterministic polynomial-time-hard problem. Metaheuristics compose the principal process of the proposed framework, as they balance a desirable tradeoff between the computational resource utilization and the quality of the obtained solution. This framework enables the constructed model to fit future data and facilitates the application of various metaheuristics. Competitive results are achieved by the proposed metaheuristic-based framework in the presented simulation

A BERT Framework to Sentiment Analysis of Tweets

Sentiment analysis has been widely used in microblogging sites such as Twitter in recent decades, where millions of users express their opinions and thoughts because of its short and simple manner of expression. Several studies reveal the state of sentiment which does not express sentiment based on the user context because of different lengths and ambiguous emotional information. Hence, this study proposes text classification with the use of bidirectional encoder representations from transformers (BERT) for natural language processing with other variants. The experimental findings demonstrate that the combination of BERT with CNN, BERT with RNN, and BERT with BiLSTM performs well in terms of accuracy rate, precision rate, recall rate, and F1-score compared to when it was used with Word2vec and when it was used with no variant

Long-term prognostic impact of cardiovascular comorbidities in patients with prostate cancer receiving androgen deprivation therapy: A population-based competing risk analysis.

Our study investigated how adverse cardiovascular outcomes are impacted by cardiovascular comorbidities in patients with prostate cancer treated by androgen deprivation therapy (ADT). Using prospective, population-based data, all Hong Kong patients with prostate cancer who received ADT during 1 January 1993 to 3 March 2021 were identified and followed up for the endpoint of cardiovascular hospitalization/mortality until 31 September 2021, whichever earlier. Multivariable competing risk regression was used to compare the endpoint's cumulative incidence between different combinations of major cardiovascular comorbidities (heart failure [HF], myocardial infarction [MI], stroke and/or arrhythmia), with noncardiovascular death as competing event. Altogether, 13 537 patients were included (median age 75.9 [interquartile range 70.0-81.5] years old; median follow-up 3.3 [1.5-6.7] years). Compared to those with none of prior HF/MI/stroke/arrhythmia, the incidence of the endpoint was not different in those with only stroke (subhazard ratio [SHR] 1.06 [95% confidence interval (CI): 0.92-1.23], P = .391), but was higher in those with only HF (SHR 1.67 [1.37-2.02], P < .001), arrhythmia (SHR 1.63 [1.35-1.98], P < .001) or MI (SHR 1.43 [1.14-1.79], P = .002). Those with ≥2 of HF/MI/stroke/arrhythmia had the highest incidence of the endpoint (SHR 1.94 [1.62-2.33], P < .001), among whom different major cardiovascular comorbidities had similar prognostic impacts, with the number of comorbidities present being significantly prognostic instead. In conclusion, in patients with prostate cancer receiving ADT, the sole presence of HF, MI or arrhythmia, but not stroke, may be associated with elevated cardiovascular risks. In those with ≥2 of HF/MI/stroke/arrhythmia, the number of major cardiovascular comorbidities may be prognostically more important than the type of comorbidities. [Abstract copyright: © 2023 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.

Synergistic Cytotoxic Effects of Ganoderma lucidum

Bacillus Calmette-Guérin (BCG) is conventionally used as an adjuvant immunotherapy to reduce the recurrence of bladder cancer. To address the issues of efficacy and safety, an ethanol extract of Ganoderma lucidum (GLe) was evaluated for its interaction with BCG. In a model of premalignant human uroepithelial cells (HUC-PC), GLe exerted immediate cytotoxic effects while BCG showed a delayed response, given that both were immunological active in inducing the secretion of interleukin (IL)-6, IL-8, and monocyte chemotactic protein-1 (MCP-1). Synergistic cytotoxic effects were observed when cells were either coincubated with both drugs or firstly preincubated with GLe. Synergism between GLe and BCG was demonstrated to achieve a complete cytostasis in 24 hours, and such effects were progressed in the subsequent 5 days. However, the pretreatment of GLe resulted in suppression of IL-6, IL-8, and MCP-1 secretions without affecting the cytotoxicity. Given that numerous proinflammatory cytokines are associated with the high side effects toll of BCG, results herein suggested the potential implications of GL to supplement the BCG immunotherapy in bladder cancer, for better efficacy and reducing side effects

Statin use and mortality risk in Asian patients with prostate cancer receiving androgen deprivation therapy: A population-based cohort study

Background This study aimed to examine the associations between the use of statins concurrent with androgen deprivation therapy (ADT) and the risks of mortality in Asian patients diagnosed with prostate cancer (PCa). Methods Adult patients (≥18 years old) diagnosed with PCa who were receiving any form of ADT and were being treated at public hospitals in Hong Kong from December 1999 to March 2021 were retrospectively identified, with follow-up conducted until September 2021. Patients who had received medical castration for <180 days without subsequent bilateral orchidectomy, those who had used statins concurrently with ADT for <180 days, and those with missing baseline total cholesterol levels were excluded. Statin users were defined as individuals who had used statins for ≥180 days concurrent with ADT, while non-users were those who had not used any statins. PCa-related mortality was the primary outcome, while all-cause mortality served as the secondary outcome. Inverse probability treatment weighting was employed to balance the covariates. Results A total of 4920 patients were included, consisting of 2578 statin users and 2342 non-users (mean age 76.1 ± 8.2 years). Over a mean follow-up period of 4.2 ± 3.3 years, it was observed that statin users had significantly lower risks of both PCa-related mortality (weighted hazard ratio [wHR] 0.56 [95% confidence interval (CI) 0.48, 0.65], p < 0.001) and all-cause mortality (wHR 0.57 [95% CI 0.51, 0.63], p < 0.001), regardless of the type of ADT used. Notably, these associations were more pronounced among patients with less advanced PCa, as indicated by the absence of androgen receptor antagonist or chemotherapy usage (p value for interaction <0.001 for both outcomes). Conclusion(s) The use of statins concurrent with ADT was associated with reduced mortality risks among Asian patients with PCa. These findings suggest the need for additional research to explore the potential role of statins in the treatment of PCa patients

Metformin use and hospital attendance-related resources utilization among diabetic patients with prostate cancer on androgen deprivation therapy: A population-based cohort study

Background Androgen deprivation therapy (ADT), used increasingly in the treatment of prostate cancer (PCa), negatively influences glycemic control in diabetes and is associated with an increased risk of diabetes complications where hospitalization commonly ensues. Metformin could decrease the metabolic consequences of ADT and enhance its effect. This study examined the association of metformin use with healthcare resources utilization among diabetic, PCa patients receiving ADT. Methods Diabetic adults with PCa on ADT in Hong Kong between December 1999 and March 2021 were identified. Patients with <6 months of concurrent metformin and ADT use were excluded. All included patients were followed up until September 2021. The outcomes were hospital attendances and related costs. Results In total, 1,284 metformin users and 687 non-users were studied. Over 8,045 person-years, 9,049 accident and emergency (A&E), and 21,262 inpatient attendances, with 11,2781 days of hospitalization were observed. Metformin users had significantly fewer A&E attendances (incidence rate ratio (IRR): 0.61 [95% confidence interval 0.54–0.69], p < 0.001), inpatient attendances (IRR: 0.57 [0.48–0.67], p < 0.001), and days of hospitalization (IRR: 0.55 [0.42–0.72], p < 0.001). Annual attendance costs were lower for metformin users than non-users (cost ratio: 0.28 [0.10–0.80], p = 0.017). Conclusions Metformin use was associated with decreased hospital attendances, days of hospitalization, and associated costs, which could help reduce healthcare resource utilization following ADT in the treatment of PCa

Temporal trends in cardiovascular burden among patients with prostate cancer receiving androgen deprivation therapy: a population-based cohort study

Background Although androgen deprivation therapy (ADT) is associated with cardiovascular risks, the extent and temporal trends of cardiovascular burden amongst patients with prostate cancer receiving ADT are unclear. Methods This retrospective cohort study analyzed adults with PCa receiving ADT between 1993–2021 in Hong Kong, with follow-up until 31/9/2021 for the primary outcome of major adverse cardiovascular events (MACE; composite of cardiovascular mortality, myocardial infarction, stroke, and heart failure), and the secondary outcome of mortality. Patients were stratified into four groups by the year of ADT initiation for comparisons. Results Altogether, 13,537 patients were included (mean age 75.5 ± 8.5 years old; mean follow-up 4.7 ± 4.3 years). More recent recipients of ADT had more cardiovascular risk factors and used more cardiovascular or antidiabetic medications. More recent recipients of ADT had higher risk of MACE (most recent (2015–2021) vs least recent (1993–2000) group: hazard ratio 1.33 [1.11, 1.59], P = 0.002; Ptrend < 0.001), but lower risk of mortality (hazard ratio 0.76 [0.70, 0.83], P < 0.001; Ptrend < 0.001). The 5-year risk of MACE and mortality for the most recent group were 22.5% [20.9%, 24.2%] and 52.9% [51.3%, 54.6%], respectively. Conclusions Cardiovascular risk factors were increasingly prevalent amongst patients with prostate cancer receiving ADT, with increasing risk of MACE despite decreasing mortality

HbA1c variability and cardiovascular events in patients with prostate cancer receiving androgen deprivation therapy

Androgen deprivation therapy (ADT) worsens glycaemic control and cardiovascular outcomes. The prognostic value of visit-to-visit HbA1c variability (VVHV) has been unexplored in prostate cancer (PCa) patients receiving ADT. To explore the effect of ADT on VVHV and the cardiovascular prognostic value of VVHV. PCa patients receiving ADT in Hong Kong between January 1, 1993 and March 31, 2021 were included in this retrospective cohort study. Those with fewer than three HbA1c results available within 3 yr after ADT initiation, <6 mo of ADT, missing baseline HbA1c, prior diagnosis of any component of major adverse cardiovascular events (MACEs), and MACEs occurring within 3 yr were excluded. Patients were followed up until September 31, 2021. The outcome was MACEs (composite of heart failure, myocardial infarction, stroke, and cardiovascular mortality). VVHV was calculated from HbA1c levels within 3 yr after and, separately where available, before ADT initiation using coefficient of variation (CV; standard deviation [SD] divided by mean) and average real variability (ARV; average difference between consecutive measurements). Altogether, 1065 patients were analysed (median age 74.4 yr old [interquartile range 68.3-79.5 yr]). In 709 patients with VVHV available before and after ADT initiation, VVHV increased after ADT initiation (  < 0.001), with 473 (66.2%) and 474 (66.9%) having increased CV and ARV, respectively. Over a median follow-up of 4.3 yr (2.8-6.7 yr), higher VVHV was associated with a higher risk of MACEs (adjusted hazard ratio [per SD] for CV 1.21 [95% confidence interval: 1.02, 1.43],  = 0.029; ARV 1.25 [1.06, 1.48],  = 0.008). Limitations included residual confounding and selection bias. In PCa patients receiving ADT, VVHV increased after ADT initiation. Higher VVHV was associated with an increased risk of MACEs. In prostate cancer patients receiving androgen deprivation therapy (ADT), glycaemic control is less stable after initiating ADT, which was associated with an increased cardiovascular risk. [Abstract copyright: © 2022 The Authors. Published by Elsevier B.V. on behalf of European Association of Urology.

Aberrant Transferrin and Ferritin Upregulation Elicits Iron Accumulation and Oxidative Inflammaging Causing Ferroptosis and Undermines Estradiol Biosynthesis in Aging Rat Ovaries by Upregulating NF-Κb-Activated Inducible Nitric Oxide Synthase: First Demonstration of an Intricate Mechanism

We report herein a novel mechanism, unraveled by proteomics and validated by in vitro and in vivo studies, of the aberrant aging-associated upregulation of ovarian transferrin and ferritin in rat ovaries. The ovarian mass and serum estradiol titer plummeted while the ovarian labile ferrous iron and total iron levels escalated with age in rats. Oxidative stress markers, such as nitrite/nitrate, 3-nitrotyrosine, and 4-hydroxy-2-nonenal, accumulated in the aging ovaries due to an aberrant upregulation of the ovarian transferrin, ferritin light/heavy chains, and iron regulatory protein 2(IRP2)-mediated transferrin receptor 1 (TfR1). Ferritin inhibited estradiol biosynthesis in ovarian granulosa cells in vitro via the upregulation of a nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and p65/p50-induced oxidative and inflammatory factor inducible nitric oxide synthase (iNOS). An in vivo study demonstrated how the age-associated activation of NF-κB induced the upregulation of iNOS and the tumor necrosis factor α (TNFα). The downregulation of the keap1-mediated nuclear factor erythroid 2-related factor 2 (Nrf2), that induced a decrease in glutathione peroxidase 4 (GPX4), was observed. The aberrant transferrin and ferritin upregulation triggered an iron accumulation via the upregulation of an IRP2-induced TfR1. This culminates in NF-κB-iNOS-mediated ovarian oxi-inflamm-aging and serum estradiol decrement in naturally aging rats. The iron accumulation and the effect on ferroptosis-related proteins including the GPX4, TfR1, Nrf2, Keap1, and ferritin heavy chain, as in testicular ferroptosis, indicated the triggering of ferroptosis. In young rats, an intraovarian injection of an adenovirus, which expressed iron regulatory proteins, upregulated the ovarian NF-κB/iNOS and downregulated the GPX4. These novel findings have contributed to a prompt translational research on the ovarian aging-associated iron metabolism and aging-associated ovarian diseases