Automated solution-phase synthesis of β-mannans

In order to provide a strategy which could produce the biologically important beta-mannans in a highly efficient and economical way, this dissertation illustrates the development of the automated solution-phase synthesis of different beta-mannans including the fungal beta-1,2-mannans by using both oxidation-reduction and beta-directing mannuronate strategies, and also reveals a new strategy for beta-mannan synthesis by reduction of mannuronate esters to alcohols. The following chapter shows the power of this automated solution-phase method to create beta-1,4-mannuronate and beta-1,4-mannan oligomers up to hexasaccharides. The subsequent chapter demonstrates the application of this new beta-mannan synthesis strategy for the synthesis of the insect N-glycan terminal trimannosides for fluorous microarray and isothermal titration calorimetry (ITC) studies to investigate the binding affinity of the pea enation mosaic virus (PEMV) in the aphid digestion system for clues to the virus transmission pathway of the virus in these notorious pests. Finally, the automated solution-phase synthesis of beta-1,6-mannan and beta-1,3-mannan oligomers presents the scope of the automated solution-phase synthesis of beta-mannans and its potential for synthesizing other oligosaccharides containing this challenging linkage

Development of High-Productivity Continuous Ethanol Production using PVA-Immobilized Zymomonas mobilis in an Immobilized-Cells Fermenter

Ethanol as one of renewable energy was being considered an excellent alternative clean-burning fuel to replace gasoline. Continuous ethanol fermentation systems had offered important economic advantages compared to traditional systems. Fermentation rates were significantly improved, especially when continuous fermentation was integrated with cell immobilization techniques to enrich the cells concentration in fermentor. Growing cells of Zymomonas mobilis immobilized in polyvinyl alcohol (PVA) gel beads were employed in an immobilized-cells fermentor for continuous ethanol fermentation from glucose. The glucose loading, dilution rate, and cells loading were varied in order to determine which best condition employed in obtaining both high ethanol production and low residual glucose with high dilution rate. In this study, 20 g/L, 100 g/L, 125 g/L and 150 g/L of glucose concentration and 20% (w/v), 40% (w/v) and 50% (w/v) of cells loading were employed with range of dilution rate at 0.25 to 1 h-1. The most stable production was obtained for 25 days by employing 100 g/L of glucose loading. Meanwhile, the results also exhibited that 125 g/L of glucose loading as well as 40% (w/v) of cells loading yielded high ethanol concentration, high ethanol productivity, and acceptable residual glucose at 62.97 g/L, 15.74 g/L/h and 0.16 g/L, respectively. Furthermore, the dilution rate of 4 hour with 100 g/L and 40% (w/v) of glucose and cells loading was considered as the optimum condition with ethanol production, ethanol productivity and residual glucose obtained were 49.89 g/L, 12.47 g/L/h, and 2.04 g/L, respectively. This recent study investigated ethanol inhibition as well. The present research had proved that high sugar concentration was successfully converted to ethanol. These achieved results were promising for further study

Existence theorems for a crystal surface model involving the p-Laplace operator

The manufacturing of crystal films lies at the heart of modern nanotechnology. How to accurately predict the motion of a crystal surface is of fundamental importance. Many continuum models have been developed for this purpose, including a number of PDE models, which are often obtained as the continuum limit of a family of kinetic Monte Carlo models of crystal surface relaxation that includes both the solid-on-solid and discrete Gaussian models. In this paper we offer an analytical perspective into some of these models. To be specific, we study the existence of a weak solution to the boundary value problem for the equation - \Delta e^{-\mbox{div}\left(|\nabla u|^{p-2}\nabla u\right)}+au=f, where $p>1, a>0$ are given numbers and $f$ is a given function. This problem is derived from a crystal surface model proposed by J.L.~Marzuola and J.~Weare (2013 Physical Review, E 88, 032403). The mathematical challenge is due to the fact that the principal term in our equation is an exponential function of a p-Laplacian. Existence of a suitably-defined weak solution is established under the assumptions that $p\in(1,2], \ N\leq 4$, and $f\in W^{1,p}$. Our investigations reveal that the key to our existence assertion is how to control the set where -\mbox{div}\left(|\nabla u|^{p-2}\nabla u\right) is $\pm\infty$

Nocturnal CPAP improves walking capacity in COPD patients with obstructive sleep apnoea

BACKGROUND: Exercise limitation is an important issue in patients with chronic obstructive pulmonary disease (COPD), and it often co-exists with obstructive sleep apnoea (overlap syndrome). This study examined the effects of nocturnal continuous positive airway pressure (CPAP) treatment on walking capacity in COPD patients with or without obstructive sleep apnoea. METHODS: Forty-four stable moderate-to-severe COPD patients were recruited and completed this study. They all underwent polysomnography, CPAP titration, accommodation, and treatment with adequate pressure. The incremental shuttle walking test was used to measure walking capacity at baseline and after two nights of CPAP treatment. Urinary catecholamine and heart rate variability were measured before and after CPAP treatment. RESULTS: After two nights of CPAP treatment, the apnoea-hypopnoea index and oxygen desaturation index significantly improved in both overlap syndrome and COPD patients, however these changes were significantly greater in the overlap syndrome than in the COPD group. Sleep architecture and autonomic dysfunction significantly improved in the overlap syndrome group but not in the COPD group. CPAP treatment was associated with an increased walking capacity from baseline from 226.4 ± 95.3 m to 288.6 ± 94.6 m (P < 0.05), and decreased urinary catecholamine levels, pre-exercise heart rate, oxygenation, and Borg scale in the overlap syndrome group. An improvement in the apnoea-hypopnoea index was an independent factor associated with the increase in walking distance (r = 0.564). CONCLUSION: Nocturnal CPAP may improve walking capacity in COPD patients with overlap syndrome. TRIAL REGISTRATION: NCT0091426

The effectiveness of different health education strategies in people with pre-diabetes: A randomized controlled trial

Background. People with pre-diabetes often lack knowledge of their risks of developing diabetes. In one of our previous study, Multi-Approach Health Education was shown evidence to be effective on health behavior of reducing risks of developing diabetes. However, which one approach is really effective and efficient need further investigation. Purpose. To examine the effects of different intervention strategies on diabetes prevention knowledge, exercise, dietary behavior, and physiological indicators for people with pre-diabetes. Methods. This was a randomly controlled trial. People who received health examination and were found fasting blood glucose higher than normal, between 100 - 125 mg/dl in 2011 were recruited. Three types of intervention were randomly assigned to 3 groups respectively. The control group (n=51) received a health education lecture. One experimental group (n=48) received the identical lecture plus telephone encouragement. The second experimental group (n=41) received the identical lecture plus a health reminder poster in their daily life. The outcomes were evaluated for the change in knowledge of diabetes prevention, exercise behavior, dietary behavior, and physiological outcomes at 6 and 12 weeks after the lecture of three groups, respectively. Results. Three intervention strategies were equally efficacious at inducing positive behavioral changes but overall the magnitudes of physiological changes were the same. In general, the maximum change in parameters was achieved after 6 weeks and maintained in the second 6 weeks of the study. Conclusions. Educating people with pre-diabetes about their condition can have a positive effect upon their health behaviors. However, education lecture coupled with a telephone follow up or plus educational posters were found no more effective than lecture alone. The lecture alone of health education may be enough for people with pre-diabetes, but the long term effect needs further investigation

GCNs-Net: A Graph Convolutional Neural Network Approach for Decoding Time-resolved EEG Motor Imagery Signals

Towards developing effective and efficient brain-computer interface (BCI) systems, precise decoding of brain activity measured by electroencephalogram (EEG), is highly demanded. Traditional works classify EEG signals without considering the topological relationship among electrodes. However, neuroscience research has increasingly emphasized network patterns of brain dynamics. Thus, the Euclidean structure of electrodes might not adequately reflect the interaction between signals. To fill the gap, a novel deep learning framework based on the graph convolutional neural networks (GCNs) was presented to enhance the decoding performance of raw EEG signals during different types of motor imagery (MI) tasks while cooperating with the functional topological relationship of electrodes. Based on the absolute Pearson's matrix of overall signals, the graph Laplacian of EEG electrodes was built up. The GCNs-Net constructed by graph convolutional layers learns the generalized features. The followed pooling layers reduce dimensionality, and the fully-connected softmax layer derives the final prediction. The introduced approach has been shown to converge for both personalized and group-wise predictions. It has achieved the highest averaged accuracy, 93.056% and 88.57% (PhysioNet Dataset), 96.24% and 80.89% (High Gamma Dataset), at the subject and group level, respectively, compared with existing studies, which suggests adaptability and robustness to individual variability. Moreover, the performance was stably reproducible among repetitive experiments for cross-validation. To conclude, the GCNs-Net filters EEG signals based on the functional topological relationship, which manages to decode relevant features for brain motor imagery

Green tea extract supplementation ameliorates CCl4-induced hepatic oxidative stress, fibrosis, and acute-phase protein expression in rat

Background/PurposeWe evaluated the long-term effects of green tea extract (GTE) supplementation on oxidative stress, biliary acute phase protein expression, and liver function in CCl4-induced chronic liver injury.MethodsWe evaluated the antioxidant activity of GTE in comparison with those of vitamin C, vitamin E, and β-carotene in vitro by using an ultrasensitive chemiluminescence analyzer. Chronic liver injury was induced by intraperitoneally administering carbon tetrachloride (CCl4) (1mL/kg body weight, twice weekly) to female Wistar rats for 8 weeks. The effects of low (4mg/kg body weight per day) and high (20mg/kg body weight per day) doses of intragastric GTE on CCl4-induced liver dysfunction and fibrosis were examined by measuring the bile and blood reactive oxygen species levels and biochemical parameters by using Western blot and two-dimensional polyacrylamide gel electrophoresis techniques.ResultsGTE has greater scavenging activity against O2–, H2O2, and Hypochlorous acid (HOCl) in vitro than vitamin C, vitamin E, and β-carotene do. In vivo, CCl4 markedly increased bile and blood reactive oxygen species production, lipid accumulation, number of infiltrated leukocytes, fibrosis, hepatic hydroxyproline content, and plasma alanine aminotransferase and aspartate aminotransferase activities, and reduced plasma albumin levels. Two-dimensional polyacrylamide gel electrophoresis revealed that CCl4 increased the acute-phase expression of six biliary proteins and decreased hepatic B-cell lymphoma 2 (Bcl-2), catalase, and CuZn superoxide dismutase protein expression. GTE supplementation attenuated CCl4-enhanced oxidative stress, levels of biochemical parameters, pathology, and acute-phase protein secretion, and preserved antioxidant/antiapoptotic protein expression.ConclusionGTE supplementation attenuates CCl4-induced hepatic oxidative stress, fibrosis, acute phase protein excretion, and hepatic dysfunction via the antioxidant and antiapoptotic defense mechanisms