APPLICATION OF IMAGE-BASED HIGH CONTENT ANALYSIS FOR THE SCREENING OF BIOACTIVE NATURAL PRODUCTS

Each bioactive compound induces phenotypic changes in target cells that can be made visible by labelling selected molecules of the cells with fluorescent dyes and/or directly observed under the high-throughput microscope. A comparison of the cellular phenotype induced by a compound of interest with known cellular targets allows predicting its mode of action. Over the past 15 years, high-throughput microscopy has been one of the fastest growing fields in cell biology. When combined with automated multiparametric image and data analysis, it is referred to as high-content screening (HCS). Whilst HCS has been successfully applied to the bioactivity characterization of natural products, recent studies used automated microscopy and software to increase speed and to reduce subjective interpretation. In 2017, Institute of Natural Products Chemistry (INPC-VAST) has been equipped with a HCS platform (Olympus Scan^R) that designed for fully automated image acquisition and analysis of biological samples to visually inspect the cellular morphology induced by hit compounds as well as to discriminate from false positives. Accordingly, this short review covers the concepts of HCS and its application in screening of biologically active natural products whose molecular targets could be identified through such approaches

Factors Affecting Youtube Acceptance For Student Learning Needs

This study was conducted to demonstrate the factors that influence Vietnamese students’ acceptance of YouTube for educational purposes. Qualitative and quantitative research methods are combined to test the research hypotheses. Research data was collected using quota sampling, with a sample size of 306 students studying at universities in Vietnam. Structural equation modeling (SEM) helps demonstrate that five factors positively affect the intention to use YouTube for student learning needs. These factors include performance expectancy, effort expectancy, hedonic motivation, social influence, and flexibility. Furthermore, research has demonstrated the positive impact of intentional use on the behavioral usage of YouTube for the educational requirements of Vietnamese students. The study provides a valuable reference for educational administrators and researchers

Determinants of Customer Intentions to Use Self-Service Technology-Based Options for Recoveries

Service firms continually seek innovative ways to meet customer needs while improving efficiencies. Self-service technologies (SSTs) (i.e., ATM, self-service checkouts in supermarkets, and self-check-in at airports) have offered solutions that enable such benefits. Unfortunately, while SSTs can provide tremendous benefits for services, they also inevitably fail. SST failures present a unique challenge to service firms because problems generally happen without the presence of service personnel. To counter this problem, a different form of recovery has emerged – SST-based recovery, which refers to SST-facilitated recovery in which customers fix the SST failure by themselves, using a self-service technological interface (e.g., help-guide, virtual onscreen assistant, autonomous robot, chatbot). SST-based recovery is a highly suitable recovery solution for the SST context where service personnel availability is often limited. SST-based recovery also introduces a very different kind of service experience to the traditional employee-led recovery (i.e., increased customer responsibility, highly technological-based, low employee presence), therefore it is difficult to apply the knowledge from the existing service recovery literature in traditional contexts to the SST-based recovery context. This form of recovery has also received limited attention from marketing scholars despite the growing importance of it to service managers. Thus, more research with a specific focus on SST-based recovery is required to provide a better understanding of this form of recovery. Centred on SST-based recovery, this thesis contributes to the current literature by improving the understanding of customer response to SST-based recovery. It provides a framework for the way in which customers’ perception of the SST-based recovery shapes their intentions towards the recovery option. The thesis consists of three self-contained, but interrelated, papers. In paper 1, a conceptual framework is presented, which extends the stress and coping theory to delineate the process of customer cognitive appraisal and its role in shaping customer intention towards using SST-based recovery. Specifically, the framework proposes failure appraisal and recovery appraisal as two components of the customer cognitive appraisal process. The framework also puts a specific focus on customer emotions, which are posited to result from failure appraisal and directly influence intentions towards SST-based recovery. Finally, relevant individual characteristics that influence customer failure and recovery appraisals are also identified and discussed. Managerial implication and an agenda for future research are provided in the paper. Building on the conceptual development in paper 1, paper 2 takes a narrower focus and empirically tests a model of customer intentions to use SST-based recovery, as a result of the customer’s perceived control and risk. Drawing on control theory, perceived control is proposed to be a key factor in customers’ decision towards using SST-based recovery. The central proposition is that customers who perceive a heightened level of control towards the SST-based recovery believe that they can exert power over the process and outcome of SST-based recovery, and will show a greater intention towards the recovery option. Furthermore, when customers believe that they have control over the SST-based recovery, this reduces perceived risk, which, in turn, increases intentions to use the SST-based recovery process. Results from an online panel database provides support for the research model. The theoretical and managerial implications of this study are discussed. Consistent with paper 2, paper 3 further explores the role of perceived control as a key factor in a customer’s decision to use SST-based recovery. The findings from paper 2 are expanded on through an investigation of the dual impact of personal control, a state of being, and the contextual circumstance of perceived control of the SST recovery process. Drawing on learned helplessness theory, the study’s proposition is that customers who have a low degree of personal control will exhibit a low perception of control towards SST-based recovery; the opposite is true for individuals with a high degree of personal control. In turn, the customer’s perception of control over SST-based recovery will have a positive impact on efficiency and positive anticipated emotions associated with SST-based recovery, both of which ultimately drive customer intention towards the recovery option. The empirical results support the research model. By investigating both the antecedent and the impact of perceived control of SST-based recovery, this paper enriches understanding of this essential concept in the SST recovery context. Additionally, the identification of personal control as an important predictor of customer perception of control towards SST-based recovery provides the first step in the application of individual difference variables that can aid SST managers in managing customer perception in the SST recovery domain. The collected data were analysed through SPSS, PROCESS, and SmartPLS. The empirical results provided by paper 2 and 3 indicate that perceived control, risk, efficiency and positive emotions have a direct impact on customer intentions towards using SST-based recovery. Perceived risk, efficiency, and positive emotions demonstrate mediating effects on the relationship between perceived control and intentions towards using SST-based recovery. Additionally, personal control exhibits a positive effect on perceived control. Overall, the conceptual framework (paper 1) together with the empirical results (paper 2 and 3) unravel the processes by which SST customers come to their recovery decisions. The research sheds light on the set of variables that shape customer intentions to use SST-based recovery following SST failures and, in particular, the importance of a customer’s perceived control of the SST-based recovery process. The current thesis highlights the need for a customer-focused perspective in explaining customer decision-making on using SST-based recovery. Service firms can utilise the research findings to improve their recovery strategies and derive successful tactics for encouraging customer use of SST-based recovery.Thesis (Ph.D.) -- University of Adelaide, Business School, 202

Sulfilimines et sulfoximines énantiomériquement pures : synthèse et applications en catalyse

Sulfoximines belong to a family of compounds with various application areas. They are used as auxiliaries or ligands for asymmetric synthesis and classified as high potential groups in biologically active compounds. Fluorinated sulfoximines are even more scarce and difficult to access, but special properties induced by fluorine, have attracted particular attention. They have been successfully used as (per)-fluoroalkylating reagent or as super-electron-withdrawing groups. However, there are only a few examples of fluorinated sulfoximines in bioactive compounds. To our knowledge, S-perfluoroalkylated sulfoximines have never been used as ligands of metals or organocatalysts so far.The Thesis focuses on the synthesis and functionalization of fluorinated sulfoximines for the preparation of chiral ligands and/or organocatalysts. It is divided into three chapters.The first chapter deals with the synthesis of enantiopure fluorinated sulfoximines and sulfilimines. During our synthesis, several methods were used, for example, separation of diastereoisomers by using camphorsulphonic acid, and the asymmetric oxidation of Kagan, Modena, Uemura as well as the asymmetric oxidizing imination. The SFC (Supercritical Fluid Chromatography) semi-preparative permits to separate the different enantiomers of fluorinated sulfilimines. Oxidation of sulfilimines led to the formation of enantiopure sulfoximines in good yields. These sulfilimines and sulfoximines are stable retaining their absolute configuration. Optical characteristics were measured and their structures were determined by X-ray diffractions. The second chapter focuses mainly on the N-functionalization of sulfoximines and their developments as organocatalysts and/or ligands for catalysis. Coupling reaction of free sulfoximines with halogenated aromatic under microwave activation led to the formation of products in good yields within short reaction time. This development has also been used to prepare chiral ligands/ organocatalysts. These new chiral fluorinated sulfoximines have been applied in catalytic processes for Friedel-Crafts reaction, Biginelli transformation and as Shibata’s asymmetric trifluoromethylation reagent. We also showed that these compounds may be used as chiral ligands or organocatalysts in Mukaiyama reaction or in Diels-Alder cycloaddition affording products in good yields.The last chapter is based on the functionalization of fluorinated sulfoximines by an ortholithiation reaction. In this part, we have demonstrated that the fluorinated sulfoximine function acts as ortho-directing group. This allowed us to access a wide variety of new ortho-substituted sulfoximine structures. Ortho-derivatives were used as reagents in Sonogashira reaction, in the preparation of novel trifluoromethylation reagents and in the synthesis of some biologically active compound analogues.Les sulfoximines sont une famille de composés dont les domaines d’applications sont très variés. Elles sont utilisées comme auxiliaires, ou ligands pour la synthèse asymétrique et répertoriées comme groupements à forts potentiels dans des composés biologiquement actifs. Les sulfoximines fluorées sont bien plus rares et difficiles d’accès, mais de par les propriétés spéciales induites par le fluor, ont récemment attirées l’attention. Elles ont notamment été utilisées avec succès en tant que réactifs de (per)-fluoroalkylation ou comme groupements super-électroattracteurs. Cependant, il n’y a que de rares exemples de sulfoximines fluorées dans des composés bioactifs. De plus, à notre connaissance, les S-perfluoroalkyl sulfoximines n’ont encore jamais été utilisées comme ligands de métaux ou organocatalyseurs.La thèse porte sur le développement de la synthèse et la fonctionnalisation des sulfoximines fluorées pour la préparation de ligands et d’organocatalyseurs, notamment en version énantiopures. Elle est divisée en 3 chapitres.Le premier chapitre porte sur la synthèse des sulfoximines et des sulfilimines fluorées énantiopures. Sur différentes étapes de la synthèse de ces composés, plusieurs méthodes ont été utilisées, par exemple, la séparation de diastéréoisomères par l’acide de camphorsulphonique, l’oxydation asymétrique de Kagan, Modena, Uemura et aussi l’imination oxydante asymétrique. La CFS (Chromatographie par Fluide Supercritique) semi-préparative a permis de séparer les différents énantiomères des sulfilimines fluorées. L’oxydation des sulfilimines a permis d’obtenir les sulfoximines énantiopures avec de bons rendements. Ces sulfilimines et sulfoximines ont des configurations absolues stables, leurs caractéristiques optiques ont été mesurées ainsi que leurs structures ont été déterminées par diffraction des rayons-X. Le deuxième chapitre est principalement axé sur la N-fonctionnalisation des sulfoximines et leurs développements comme ligands et organocatalyseurs pour la catalyse. Nous avons pu montrer que l’utilisation des micro-ondes pour activer le couplage entre les sulfoximines libres et les aromatiques halogénés permettait d’obtenir de bons résultats et même de diminuer le temps de réaction par rapport à la méthode de chauffage conventionnel. Ce développement a également été utilisé pour préparer des ligands/organocatalyseurs chiraux. Ces nouveaux ligands, sulfoximines fluorées chirales, ont été appliqués dans des procédés de catalyse pour la réaction de Friedel-Crafts, de Biginelli et même comme réactif de Shibata asymétrique pour la trifluoromethylation. Nous avons montré également que ces composés peuvent être utilisés comme ligands ou organocatalyseurs chiraux dans la réaction de Mukaiyama ou de cycloaddition de Diels-Alder conduisant aux produits avec de bons rendements.Le dernier chapitre est basé sur la fonctionnalisation des sulfoximines fluorées par une réaction inédite d’ortholithiation. Dans cette partie, nous démontrons que la fonction sulfoximine fluorée joue le rôle de groupe ortho-directeur. Cela nous a permis d’accéder à une grande variété de sulfoximines orthosubstituées aux structures totalement nouvelles. Les produits dérivés ortho ont été utilisés comme réactifs dans de nombreuses réactions: dans la réaction de Sonogashira, dans la préparation de nouveaux réactif de trifluorométhylation et dans la synthèse d’analogues de composés biologiquement actifs

POROSIMETRY BY DOUBLE-RANDOM MULTIPLE TREE STRUCTURING IN VIRTUAL CONCRETE

Two different porosimetry methods are presented in two successive papers. Inspiration for the development came from the rapidly-exploring random tree (RRT) approach used in robotics. The novel methods are applied to virtual cementitious materials produced by a modern concurrent algorithm-based discrete element modeling system, HADES. This would render possible realistically simulating all aspects of particulate matter that influence structure-sensitive features of the pore network structure in maturing concrete, namely size, shape and dispersion of aggregate and cement particles. Pore space is a complex tortuous entity. Practical methods conventionally applied for assessment of pore size distribution may fail or present biased information. Among them, mercury intrusion porosimetry and 2D quantitative image analysis are popular. The mathematical morphology operator “opening” can be applied to sections and even provide 3D information on pore size distribution, provided isotropy is guaranteed. Unfortunately, aggregate grain surfaces lead to pore anisotropy. The presented methods allow exploration of pore space in the virtual material, after which pore size distribution is derived from star volume measurements.  In addition to size of pores their continuity is of crucial importance for durability estimation. Double-random multiple tree structuring (DRaMuTS), presented herein, and random node structuring (RaNoS) provide such information. The latter method will be introduced in a next issue of IA&S

A 6DOF super element for nonlinear analysis of composite frames with partial interaction and semi-rigid connections

This paper presents a displacement-based finite element formulation for nonlinear analysis of steel - concrete composite planar frames subjected to combined action of gravity and lateral loads. A 6DOF super element is proposed for modeling composite beam, allowing for partial interaction between the steel beam and the concrete slab, semi-rigid nature of beam to column composite connection and material nonlinearity. The load control method and the displacement control method are utilized for tracing the structural equilibrium paths, and the direct method is utilized for solving the nonlinear problem. Numerical examples, concerning a two-span continuous composite beam, a portal composite frame and a six-storey composite frame, are performed. The results are compared with experience data or theoretical results from other studies and are discussed for influences of the factors mentioned above on behaviour of composite beams and composite frames

Application correlation algorithm to create a new critical depth equation for gradually varied flow in trapezoidal channel using teaching–learning and studying

The critical depth is a hydraulic factor of the flow, it plays a particularly important role in studying and designing for open channels, especially during identification of water surfaces and analyzing to determine the phenomenon of a hydraulic jump in open channel. In practice, when calculating the critical depth, only the rectangular and isosceles triangle channels have the theory equation, in other circumstances in calculating by semi empirical equations. This paper presents the general method to compute the critical depth of trapezoidal channel, the case study methodology was chosen to analyze the application of existing formulas and then offering a new equation to compute the critical depth based on the optimization algorithm in MS Excel software. This new equation will help to obtain more accurate result, which relative error of the equation is less than 0.61%, this equation has a simple structure, easy to calculate with small errors to meet the conditions to quickly calculate the critical depth, this equation is also suitable for teaching–learning and studying in the field of hydraulics

Suicide attempt in a rural area of Vietnam: Incidence, methods used and access to mental health care

OBJECTIVES: The study aims to determine the incidence of suicide attempt, describe the methods used, and assess use of health care services including mental health care after suicide attempt in a rural area of Vietnam. METHODS: All suicide attempters (104) during 2003-2007 were listed, diagnosed and re-evaluated by trained physicians according to the research criteria of the WHO Multicentre Study of Attempted Suicide. All attempters were interviewed by trained medical staff to investigate methods used, socio-demographic characteristics and use of health services. RESULTS: The yearly incidence was 10.2 per 100000 person-years, 10.6 per 100000 in males and 9.8 per 100000 in females. 99% of cases committed suicide attempt by poisoning, 62.6% by pesticides and 36.3% by pharmaceutical drugs. 34.3% reported having been in contact with somatic care and 13.2% had received mental health care. Among those who reported some treatment received, 47.5% had been in contact with official health care services, 8.1% had pharmacy keepers' consultation or were treated by traditional healers and 4% reported self treatment. CONCLUSION: The incidence of suicide attempt was lower in this population compared to other settings. While the majority of attempters use pesticides, many had used psychotropic drugs. Contact with mental health services following the attempt was very limited in this setting. Suicide prevention for this high risk group should focus on reducing access to pesticides and psychotropic drugs. Mental health services should be made more accessible in rural areas