Оптимизация нормированной переходной функции линейной цепи, описываемой характеристическим уравнением 4-го порядка

Определение параметров усилительной схемы, обеспечивающих наилучшую форму переходной характеристики, является одной из наиболее сложных задач усилительной техники. При наличии нескольких варьируемых параметров, т. е. при характеристических уравнениях выше второй степени, задача значительно усложняется и случайным варьированием или машинным перебором сочетаний параметров решить ее чрезвычайно трудно. С целью значительного сокращения усилий и времени, затрачиваемых на решение подобных задач, разработаны алгоритм и методика определения с помощью цифровых ЭВМ оптимальных значений коэффициентов коррекции переходных функций линейных целей, описываемых характеристическими уравнениями 2-й и 4-й степеней, при заданных значениях первого и второго выбросов. Приведены графики, иллюстрирующие ре­зультаты вычислений

Модифицирование матриксов из поли-L-молочной кислоты импульсным сильноточным электронным пучком

We describe the synthesis, characterisation and surface-modification of magnetic narroparticles and a poly(N-isopropylacrylamide) microgel, followed by the assembly and characterisation of magnetic nanoparticles on the microgel. To facilitate this deposition, the surface of the microgel is first modified via the layer-by-layer assembly of polyelectrolytes. One advantage of this concept is that it allows an independent optimization and fine tuning of the magnetic and thermoresponsive properties of individual components (nanoparticles and microgels) before assembling them so that the hybrid core-shell structure retains all the individual properties. The,decisive parameter when exploiting the thermoresponsive and magnetic properties in such hybrid core-shell structures is the amount of heat transfer from the magnetic core onto the thermosensitive (loaded) microgel (for the subsequent heat-triggered release of drugs). Inductive heat study reveals that the heat generated by the magnetic narroparticles is sufficient to cause the collapse of the microgel above its volume phase transition temperature. Successful confinement of positively and negatively charged magnetic nanoparticles between polyelectrolyte layers is achieved using the layer-by-layer deposition onto the microgel. Dynamic light scattering measurements show (i) the presence of each layer successfully deposited, (ii) the preservation of thermoresponsivity in the coated microgel, and (iii) that the magnetic nanoparticles do not get detached during the phase transition of the microgel. Electrophoresis measurements confirm charge reversal at every stage of layering of polycations, polyanions and magnetic nanoparticles. This unique combination of thermoresponsivity and magnetism opens up novel perspectives towards remotely controlled drug carriers. (c) 200

SAVER: Surface Autonomous Vehicle for Emergency Rescue

The design, fabrication, and testing of an unmanned surface vehicle for the NASA Micro-G NExT SAVER challenge. This device features a radio direction finding phase array to autonomously navigate to an emergency distress beacon to deliver emergency supplies

High resolution remote sensing of densely urbanised regions : a case study of Hong Kong

2008-2009 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Application of problem-based learning approach in the teaching of end of life care and its enlightenment

2011-2012 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Comparative efficacy and safety of statin and fibrate monotherapy: A systematic review and meta-analysis of head-to-head randomized controlled trials

OBJECTIVE: To assess whether in adults with dyslipidemia, statins reduce cardiovascular events, mortality, and adverse effects when compared to fibrates. METHODS: Systematic review and meta-analysis of head-to-head randomized trials of statin and fibrate monotherapy. MEDLINE, EMBASE, Cochrane, WHO International Controlled Trials Registry Platform, and ClinicalTrials.gov were searched through October 30, 2019. Trials that had a follow-up of at least 28 days, and reported mortality or a cardiovascular outcome of interest were eligible for inclusion. Efficacy outcomes were cardiovascular mortality and major cardiovascular events. Safety outcomes included myalgia, serious adverse effects, elevated serum creatinine, and elevated serum alanine aminotransferase. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using the Mantel-Haenszel fixed-effect model, and heterogeneity was assessed using the I2 statistic. RESULTS: We included 19 eligible trials that directly compared statin and fibrate monotherapy and reported mortality or a cardiovascular event. Studies had a limited duration of follow-up (range 10 weeks to 2 years). We did not find any evidence of a difference between statins and fibrates for cardiovascular mortality (OR 2.35, 95% CI 0.94-5.86, I2 = 0%; ten studies, n = 2657; low certainty), major cardiovascular events (OR 1.15, 95% CI 0.80-1.65, I2 = 13%; 19 studies, n = 7619; low certainty), and myalgia (OR 1.32, 95% CI 0.95-1.83, I2 = 0%; ten studies, n = 6090; low certainty). Statins had less serious adverse effects (OR 0.57, 95% CI 0.36-0.91, I2 = 0%; nine studies, n = 3749; moderate certainty), less elevations in serum creatinine (OR 0.17, 95% CI 0.08-0.36, I2 = 0%; six studies, n = 2553; high certainty), and more elevations in alanine aminotransferase (OR 1.43, 95% CI 1.03-1.99, I2 = 44%; seven studies, n = 5225; low certainty). CONCLUSIONS: The eligible randomized trials of statins versus fibrates were designed to assess short-term lipid outcomes, making it difficult to have certainty about the direct comparative effect on cardiovascular outcomes and mortality. With the exception of myalgia, use of a statin appeared to have a lower incidence of adverse effects compared to use of a fibrate

The Sweet Surrender: How Myeloid Cell Metabolic Plasticity Shapes the Tumor Microenvironment

Immune cells are one of the most versatile cell types, as they can tailor their metabolic activity according to their required function. In response to diverse environmental cues, immune cells undergo metabolic reprogramming to support their differentiation, proliferation and pro-inflammatory effector functions. To meet a dramatic surge in energetic demand, immune cells rewire their metabolism to utilize aerobic glycolysis. This preferential use of glycolysis even under aerobic conditions is well established in tumor cells, and is known as the “Warburg effect.” Tumor cells avidly use glucose for aerobic glycolysis, thereby creating a nutrient-starved microenvironment, outcompeting T cells for glucose, and directly inhibiting T-cell anti-tumoral effector function. Given that both immune and tumor cells use similar modes of metabolism in the tumor stroma, it is imperative to identify a therapeutic window in which immune-cell and tumor-cell glycolysis can be specifically targeted. In this review, we focus on the Warburg metabolism as well as other metabolic pathways of myeloid cells, which comprise a notable niche in the tumor environment and promote the growth and metastasis of malignant tumors. We examine how differential immune-cell activation triggers metabolic fate, and detail how this forbidding microenvironment succeeds in shutting down the vigorous anti-tumoral response. Finally, we highlight emerging therapeutic concepts that aim to target immune-cell metabolism. Improving our understanding of immunometabolism and immune-cell commitment to specific metabolic fates will help identify alternative therapeutic approaches to battle this intractable disease

Bioavailable testosterone predicts a lower risk of Alzheimer’s disease in older men: a 1-year cohort study

Oral Presentationpublished_or_final_versionThe 15th Annual Research Conference of the Department of Medicine, The University of Hong Kong, Hong Kong, 16 January 2010. In Hong Kong Medical Journal, 2010, v. 16, suppl. 1, p. 16, abstract no. 1

Effect on Baby-Friendly Hospital Steps When Hospitals Implement a Policy to Pay for Infant Formula

Background: The Baby-Friendly Hospital Initiative requires hospitals to pay market price for infant formula. No studies have specifically examined the effect of hospitals paying for infant formula on breastfeeding mothers' exposure to Baby-Friendly steps. Objectives: To investigate the effect of hospitals implementing a policy of paying for infant formula on new mothers' exposure to Baby-Friendly steps and examine the effect of exposure to Baby-Friendly steps on breastfeeding rates. Methods: We used a repeated prospective cohort study design. We recruited 2 cohorts of breastfeeding mother-infant pairs (n = 2470) in the immediate postnatal period from 4 Hong Kong public hospitals and followed them by telephone up to 12 months postpartum. We assessed participants' exposure to 6 Baby-Friendly steps by extracting data from the medical record and by maternal self-report. Results: After hospitals began paying for infant formula, new mothers were more likely to experience 4 out of 6 Baby-Friendly steps. Breastfeeding initiation within the first hour increased from 28.7% to 45%, and in-hospital exclusive breastfeeding rates increased from 17.9% to 41.4%. The proportion of mothers who experienced all 6 Baby-Friendly steps increased from 4.8% to 20.5%. The risk of weaning was progressively higher among participants experiencing fewer Baby-Friendly steps. Each additional step experienced by new mothers decreased the risk of breastfeeding cessation by 8% (hazard ratio = 0.92; 95% CI, 0.89-0.95). Conclusion: After implementing a policy of paying for infant formula, breastfeeding mothers were exposed to more Baby-Friendly steps, and exposure to more steps was significantly associated with a lower risk of breastfeeding cessation.postprin