162 research outputs found

    Anthrapyrazole cysteinyl peptides as inhibitors of AP-1 transcription factor binding.

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    Synthesis of peptides anchored to DNA by intercalating chromophores can incorporate the design principle of the naturally occurring peptide based antibiotics. This work is concerned with the synthesis of DNA anchored cysteinyl peptides designed to be potentially nucleotide sequence specific with possible affinity for the AP-l transcription site. Previous work has shown that anthraquinones and anthrapyrazoles (APZs) substituted with cationic side groups are excellent DNA intercalating agents. In this work a series of APZ analogues has been synthesised which are coupled onto the amino terminus of varying peptide sequences. Three derivatives of APZs were prepared namely 2-, 2,5- and 2,7-substituted. Eight short polypeptides (see below), all varying slightly in sequence but all containing the KCR motif (with one exception where a Cys was replaced with Ser) were combined with the APZ chromophore to give a series of intercalator-peptide molecules. Peptides were synthesised using the Fmoc strategy on a solid phase peptide synthesizer (SPPS). The peptides were then isolated by reversed-phase HPLC using a water: acetonitrile gradient. Characterisation of the peptides was carried out by matrix assisted laser desorption ionisation (MALDI) mass spectrometry and two dimensional nmr (i.e. COSY and NOESy). Anthraquinone linked peptide ligands were also synthesised using similar synthetic routes, and tested for their activity. Coupling of the two components was achieved via activation of the carboxylic acid group using PyBOP or via formation of a reactive aziridinium ion. All intercalator-peptides prepared were examined for their DNA binding properties. The methods included the effect of intercalator-peptides on the thermal denaturation of DNA and the competitive displacement of ethidium by fluorimetry. It was shown that the APZ binds to DNA by intercalation. Peptides prepared were: H2N-A-K-C-R-A-C02H; H2N-A-K-C-R-A-CONH2; H2N-A-K-S-R-A-CONH2; H2N-A-K-C-R-N-A-CONH2; H2N-A-K-C-R-K-A-CONH2; H2N-A-K-C-R-N-R-A-CONH2; H2N-A-K-C-R-K-R-ACONH2; H2N-A-A-K-C-R-A-A-CONH2. The biological activities of the intercalatorpeptides were then investigated using an electrophoretic mobility shift assay (EMSA), making use of cell nuclear extracts rich in AP-l and also c-Jun homodimer recombinant proteins. It was shown that most of the intercalatorpeptides were capable of inhibiting AP-l (fos/jun) heterodimer protein from binding to the AP-l DNA consensus sequence. Importantly, the intercalatorpeptides showed superior activity over the intercalator or peptide moieties alone. The order of binding affinity was intercalator-peptide> intercalator» peptide

    An Empirical Study of Affective Commitment: the Case of Machinery Enterprises in Hochiminh City

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    The study aims to investigate the impact of participation in decision-making (PDM) and perceived organizational support (POS) on affective commitment in machinery enterprises. The study applies structural equation modeling (SEM) to test the research hypotheses. The authors surveyed 220 employees who work in machinery enterprises to collect data for the research. The study results indicate that both PDM and POS positively impact affective commitment. The findings provide empirical evidence to support the theoretical models that PDM and POS have a positive effect on affective commitment. The findings have implications for management theory: PDM and POS are the key antecedents of affective commitment. The findings also have implications for practical management in the machinery enterprises that managers should practice both PDM and POS to increase affective commitment

    Treatment of landfill leachate through struvite precipitation and nitrogen removal bacteria and poly-phosphate bacteria (in-pots experiment)

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    Abstract— Landfill leacheate is a type of wastewater which contains large amounts of nitrogen and phosphorus, therefore it needed to be treated before releasing to directly to the environment. The combination between struvite precipitation and nitrogen removal and poly-P bacteria into wastewater for landfill leachate treatment has been found to be a cost-effective practive, a viable technology in terms of environmental protection and sustainability, especially in the developing-countries. For optimum struvite crystallization from landfill leachate, the Mg:PO4 molar ratio as (1.2:1) was used, the pH of reaction was adjusted to 9 and the sample was stirred continously during 40 minutes. The supernatant sample was then added 1% nitrogen removal bacteria (Pseudomonas stutzeri D3b strain) and 1% poly-P bacteria (Kurthia sp. TGT1013L strain), 5 g glucose/L and aeration 12/24h during 3 days, ammonium concentration reduced significantly from 1076 mg/L to 1.5 mg/L and orthophosphate concentration decreased noticeably from 24.91 mg/L to 7.6 mg/L

    Development of a nutritional model to define the energy and protein requirements of cobia, Rachycentron canadum

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    This study assessed the protein and energy requirements of Cobia (Rachycentron canadum) using a bio-energetic factorial approach. Using a series of inter-related studies, several parameters were defined to enable the construction of a bio-energetic factorial model for this species. The studies included two controlled laboratory experiments and also extensive field-data collection from commercial and research farms in Vietnam. The devised model includes parameters for both maintenance and protein demands; the effect of fish live-weight on maintenance protein (LW0.697), lipid (LW0.972), and energy demands (LW0.815); the efficiencies of protein, lipid and energy utilisation at various protein, lipid and energy intake levels; and the variability in whole body composition with varying live-weight. The protein utilisation efficiencies (0.456·[protein intake]−0.445), lipid utilisation efficiencies (1.292·[lipid intake]−1.120) and energy utilisation efficiencies (0.651·[energy intake]−48.41) were similar to other carnivorous fish species. However, the maintenance requirements for both energy (74.3kJ/kgBW0.8/d−at 28°C) and protein (0.99g/kgBW0.7/d at 27.9°C) were about double to other species. Using this modelling approach it was possible to iteratively derive optimal dietary protein and energy specifications for this species

    The Impact of Social Media Marketing on Brand Awareness and Purchase Intention: Case Study of Vietnam's domestic fashion brands

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    The study aimed to examine the impact of social media marketing on brand awareness and purchase intention for Vietnamese domestic fashion brands. Quantitative research was conducted on 302 Vietnamese people of Generation Z. The questionnaire designed on Google forms was sent to research samples who were willing to participate. Research results determined the role and benefits of social media marketing in 2 aspects: (1) information about the brand of social media marketing on social networks and (2) brand engagement on social networks. Social media marketing has a positive impact on brand awareness and purchase intention of Vietnamese domestic fashion brands. In particular, brand information when communicating on social networks has a direct and positive impact on brand awareness and purchase intention. Brand engagement on social networks has a positive direct impact on brand awareness and a positive indirect impact on purchase intention through brand awareness. The research results show that Vietnamese domestic fashion brands do quite well in social media marketing, and are highly appreciated by the online community of generation Z in Vietnam. In the future, in order to improve brand awareness and purchase intention, Vietnamese domestic fashion brands need to pay attention to the brand information properties of social media marketing programs and need to invest more in brand engagement characteristics of social networks. Keywords: social media marketing, brand awareness, purchase intentio

    Effect of Silver Nanowire Dimension to Ammonia Adsorption of Graphene-silver Nanowires Hybrid

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    In this report, we study the effect of silver nanowires (AgNws) dimension to electrical properties of rGO/AgNws hybrid. The alteration of these electrical properties leads the difference of ammonia sensibility of the rGO/AgNws hybrid based sensing devices. When the rGO is accompanied by AgNws of different sizes from \sim 500$~\text{nm to } 10\;\mum, the ammonia sensitivity of these hybrids change from 60% to 340% alteration compared with the bare rGO material

    Determinants Influencing Entrepreneurial Intention in Hanoi, Vietnam

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    This research employed survey data from 204 students between two groups of  economics and technical majors in Hanoi city for assessing the impact levels of determinants on entrepreneurial intention. The results show that a number of determinants including Need for achievement, Self-efficacy, and Instrumental readiness have positive impacts on student’s entrepreneurial intention. Besides, this study is also to create a basis for  comparative students among different economics and technical majors, work exoperience, and gender. These findings are the basis to recommend policies and solutions to promote entrepreneurship movement in Vietnam. Keywords: Entrepreneurial intention, need for achievement, self-efficacy, instrumental readiness. DOI: 10.7176/EJBM/12-15-10 Publication date:May 31st 2020

    Factors Affecting Successful Quality Assurance Implementation in Vietnamese Higher Education: A Qualitative Study

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    Quality assurance and accreditation was officially introduced into the higher education system in Vietnam over ten years ago. It is evident that quality assurance has resulted in positive impacts on university management, teaching, learning and research activities. This paper aims to explore factors that aid the successful implementation of higher education quality assurance and accreditation in Vietnam. Through semi-structured interviews with 32 participants, this study identified a number of factors that contributed to quality assurance processes, including awareness of the importance of quality assurance, better institutional manager leadership, support of university lecturers, staff, and students, and the vital responsibility of internal quality assurance staff. These confirm that internal stakeholders play an important role in undertaking quality assurance programmes and activities

    Characterization of Ag-Doped p-Type SnO Thin Films Prepared by DC Magnetron Sputtering

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    Crystalline structure and optoelectrical properties of silver-doped tin monoxide thin films with different dopant concentrations prepared by DC magnetron sputtering are investigated. The X-ray diffraction patterns reveal that the tetragonal SnO phase exhibits preferred orientations along (101) and (110) planes. Our results indicate that replacing Sn2+ in the SnO lattice with Ag+ ions produces smaller-sized crystallites, which may lead to enhanced carrier scattering at grain boundaries. This causes a deterioration in the carrier mobility, even though the carrier concentration improves by two orders of magnitude due to doping. In addition, the Ag-doped SnO thin films show a p-type semiconductor behavior, with a direct optical gap and decreasing transmittance with increasing Ag dopant concentration
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