81 research outputs found

    1,4-Cycloaddition of Anthracenes and Practical Method for the Synthesis of Chiral Diamino Alcohols

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    The dissertation presents the Diels-Alder reactions of electron-rich 9,10-unsubstituted anthracenes. DMAD is a unique dienophile being able to give 1,4-cycloadditions. The exclusive 1,4-cycloadduct was obtained from the reaction of DMAD and 1,5-bis(pyrrolidin-1-yl)anthracene in 78% yield, the highest yield for the 1,4-cycloaddition of 9,10-unsubstituted anthracenes. The work also describes a practical method for the synthesis of chiral diamino alcohols with up to two chiral centres through the hydrolysis of 2-imidazolines. By applying this approach, Phaol was synthesised in large scale and in high yield (71% total yield from (S)-phenylalaninol). The catalytic activity in the asymmetric Michael reaction of 2-nitropropane and α,β-unsaturated enones of (S)-2-(((S)-2-amino-3-phenylpropyl)amino)-3-phenylpropan-1-ol, a diamino alcohol prepared in gram scale, was screened. In addition, the catalytic activity in the MVK-based MBH reaction of the two 2-imidazolines (1R, 2S)-1-((S)-4-(tert-butyl)-2-(4-methoxyphenyl)-4,5-dihydro-1H-imidazol-1-yl)-2,3-dihydro-1H-inden-2-ol and (1R, 2S)-1-((S)-4-(tert-butyl)-2-(3,4,5-trimethoxyphenyl)-4,5-dihydro-1H-imidazol-1-yl)-2,3-dihydro-1H-inden-2-ol was tested

    A Passivity-based Control Combined with Sliding Mode Control for a DC-DC Boost Power Converter

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    In this paper, a passivity-based control combined with sliding mode control for a DC-DC boost power converter is proposed. Moreover, a passivity-based control for a DC-DC boost power converter is also proposed. Using a co-ordinate transformation of state variables and control input, a DC-DC boost power converter is passive. A new plant is zero-state observable and the equilibrium point at origin of this plant is asymptotically stable. Then, a passivity-based control is applied to this plant such that the capacitor voltage is equal to the desired voltage. Additionally, the sliding mode control law is chosen such that the derivative of Lyapunov function is negative semidefinite. Finally, a passivity-based control combined with sliding mode control law is applied to this plant such that the capacitor voltage is equal to the desired voltage. The simulation results of the passivity-based control, the sliding mode control and the passivity-based control combined with sliding mode control demonstrate the effectiveness and show that the capacitor voltage is kept at the desired voltage when the desired voltage, the input voltage E and the load resistor R are changed. The results show that compared with the passivity-based control, the passivity-based control combined with sliding mode control has better performance such as shorter settling time, 8.5 ms when R changes and it has smaller steady-state error, which is indicated by the value of integral absolute error (IAE), 0.0679 when the desired voltage changes. The paper has limitations such as the assumed circuit parameters

    Gene Family Abundance Visualization based on Feature Selection Combined Deep Learning to Improve Disease Diagnosis

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    Advancements in machine learning in general and in deep learning in particular have achieved great success in numerous fields. For personalized medicine approaches, frameworks derived from learning algorithms play an important role in supporting scientists to investigate and explore novel data sources such as metagenomic data to develop and examine methodologies to improve human healthcare. Some challenges when processing this data type include its very high dimensionality and the complexity of diseases. Metagenomic data that include gene families often have millions of features. This leads to a further increase of complexity in processing and requires a huge amount of time for computation. In this study, we propose a method combining feature selection using perceptron weight-based filters and synthetic image generation to leverage deep-learning advancements in order to predict various diseases based on gene family abundance data. An experiment was conducted using gene family datasets of five diseases, i.e. liver cirrhosis, obesity, inflammatory bowel diseases, type 2 diabetes, and colorectal cancer. The proposed method provides not only visualization for gene family abundance data but also achieved a promising performance level

    Seed Health and Quality of Rice Seeds Produced by Farmer and Growing in Cho Moi District, An Giang Province, Vietnam

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    This study was conducted at Laboratory in An Giang University; the varieties examined were collected from farmer households in 2018 – they were varieties that the farmer stored for the next crop (Winter-Spring) from Autumn-Winter crop in Cho Moi district, An Giang Province, Vietnam. The research evaluated the quality of seed rice, which is provided and planted by the farmer. As a result, this study showed that almost all of the varieties of seed rice from farmer households indicated the ratio of filled-grain, the germination, and the determination of seedling healthy, which are lower than certified variation. Besides, the samples of seed rice from farmer household have more infected fungal; especially the samples with higher in a filled-grain ratio is less infected by fungi, there were 12 types of seed borne-fungi in rice varieties from the farmer (in Cho Moi district), included: Alternaria padwickii, Rhizoctonia solani, Aspergillus oryzae, Bipolaris oryzae, Cercospora janseana, Curvularia lunata, Fusarium moniliforme, Pyricularia oryzae, Sarocladium oryzae, Tilletia barclayana, Fusarium graminearum, and Ustilaginoidea viren

    Facile Template In-Situ Fabrication of ZnCo2O4 Nanoparticles with Highly Photocatalytic Activities under Visible-Light Irradiation

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    High specific surface area ZnCo2O4 nanoparticles were prepared via a sacrificial template accelerated hydrolysis by using nanoparticles of ZnO with highly polar properties as a template. The obtained ZnCo2O4 nanoparticles were characterized by the method of scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area measurements, Transmission electron microscopy (TEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The obtained nanoparticles were performed as a photocatalyst for the degradation of methylene blue in aqueous solution under visible irradiation. The photocatalytic degradation rate of methylene blue onto the synthesized ZnCo2O4 was higher than that of commercial ZnO and synthesized ZnO template. Copyright © 2019 BCREC Group. All rights reserved

    Состояние провоспалительного цитокинового звена у больных с нестабильной стенокарадией и сахарным диабетом 2-го типа в зависимости от функционального класса хронической сердечной недостаточности

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    Проанализировано состояние провоспалительного звена цитокинов у больных с нестабильной стенокардией (НС) и сопутствующим сахарным диабетом (СД) 2−го типа в зависимости от функционального класса хронической сердечной недостаточности (ХСН). Нарастание проявлений сердечной декомпенсации у больных с НС и СД 2−го типа ассоциируется с высокой активностью провоспалительного цитокинового звена, представленного фактором некроза опухолей−α и интерлейкином−6. Повышение функционального класса ХСН характеризуется увеличением инсулинорезистентности у больных с НС и СД 2−го типа.Проаналізовано стан прозапальної ланки цитокінів у хворих із нестабільною стенокардією (НС) та супутнім цукровим діабетом (ЦД) 2−го типу залежно від функціонального класу хронічної серцевої недостатності (ХСН). Наростання проявів серцевої декомпенсації у хворих із НС та СД 2−го типу асоціюється з високою активністю прозапальної цитокінової ланки, представленої фактором некрозу пухлин−α та інтерлейкіном−6. Підвищення функціонального класу ХСН характеризується зростанням інсулінорезистентності у хворих із НС та ЦД 2−го типу.The state of pro−inflammatory cytokines in patients with unstable angina (UA) and associated type 2 diabetes mellitus (DM) was analyzed depending on the functional class of chronic heart failure (CHF). The increase in manifestations of cardiac decompensation in patients with UA and type 2 DM is associated with high activity of pro−inflammatory cytokine level represented by tumor necrosis factor−β and interleukin−6. Increase of functional class of CHF is characterized by increased insulin resistance in patients with UA and type 2 DM

    Kinetics of neutralizing antibodies against Omicron variant in Vietnamese healthcare workers after primary immunization with ChAdOx1-S and booster immunization with BNT162b2

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    We studied the development and persistence of neutralizing antibodies against SARS-CoV-2 ancestral strain, and Delta and Omicron (BA.1 and BA.2) variants in Vietnamese healthcare workers (HCWs) up to 15 weeks after booster vaccination. We included 47 HCWs, including group 1 (G1, N = 21) and group 2 (G2; N = 26) without and with breakthrough Delta variant infection before booster immunization, respectively). The study participants had completed primary immunization with ChAdOx1-S and booster vaccination with BNT162b2. Neutralizing antibodies were measured using a surrogate virus neutralization assay. Of the 21 study participants in G1, neutralizing antibodies against ancestral strain, Delta variant, BA.1, and BA.2 were (almost) abolished at month 8 after the second dose, but all had detectable neutralizing antibodies to the study viruses at week 2 post booster dose. Of the 26 study participants in G2, neutralizing antibody levels to BA.1 and BA.2 were significantly higher than those to the corresponding viruses measured at week 2 post breakthrough infection and before the booster dose. At week 15 post booster vaccination, neutralizing antibodies to BA.1 and BA.2 dropped significantly, with more profound changes observed in those without breakthrough Delta variant infection. Booster vaccination enhanced neutralizing activities against ancestral strain and Delta variant compared with those induced by primary vaccination. These responses were maintained at high levels for at least 15 weeks. Our findings emphasize the importance of the first booster dose in producing cross-neutralizing antibodies against Omicron variant. A second booster to maintain long-term vaccine effectiveness against the currently circulating variants merits further research

    Wearable devices for remote monitoring of hospitalized patients with COVID-19 in Vietnam

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    Patients with severe COVID-19 disease require monitoring with pulse oximetry as a minimal requirement. In many low- and middle- income countries, this has been challenging due to lack of staff and equipment. Wearable pulse oximeters potentially offer an attractive means to address this need, due to their low cost, battery operability and capacity for remote monitoring. Between July and October 2021, Ho Chi Minh City experienced its first major wave of SARS-CoV-2 infection, leading to an unprecedented demand for monitoring in hospitalized patients. We assess the feasibility of a continuous remote monitoring system for patients with COVID-19 under these circumstances as we implemented 2 different systems using wearable pulse oximeter devices in a stepwise manner across 4 departments
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